阅读说明：本技术 扩散体、照明单元和照明装置 (Diffuser, lighting unit and lighting device ) 是由 藤井佑辅 冈垣觉 于 2020-03-25 设计创作，主要内容包括：提供薄型且能够同时实现天空的再现性和颜色不均的抑制的扩散体、照明单元和照明装置。扩散体供第1光入射并出射散射光,扩散体是针对第1光表现出规定的散射能力的散射层(30)和透射第1光的透射层(40)层叠而成的,具有供第1光入射的光入射面(f21)和形成出射散射光的第1光出射面(f22)的主表面,光入射面形成于构成主表面的第1端部的端面,扩散体针对入射的第1光作为使其在散射层和透射层往复的导光路径发挥功能,散射层包含纳米级别的光学介质(302),使入射的第1光由纳米级别的光学介质散射而产生散射光,散射光的相关色温比第1光的相关色温高。(Provided are a diffuser, an illumination unit, and an illumination device that are thin and that can simultaneously achieve both sky reproducibility and color unevenness suppression. The diffuser is formed by laminating a diffusion layer (30) which can allow the 1 st light to enter and emit scattered light, the diffuser is formed by laminating a transmission layer (40) which can allow the 1 st light to pass through, and has a light incident surface (f21) which allows the 1 st light to enter and a main surface which forms a 1 st light emitting surface (f22) which emits the scattered light, the light incident surface is formed on the end surface of the 1 st end part which forms the main surface, the diffuser functions as a light guide path which enables the incident 1 st light to reciprocate between the diffusion layer and the transmission layer, the diffusion layer comprises a nano-level optical medium (302), the incident 1 st light is scattered by the nano-level optical medium to generate the scattered light, and the correlated color temperature of the scattered light is higher than the correlated color temperature of the 1 st light.)

1. A diffuser for receiving the 1 st light and emitting a scattered light,

the diffuser is formed by laminating a scattering layer exhibiting a predetermined scattering power with respect to the 1 st light and a transmission layer transmitting the 1 st light,

the diffuser has a light incident surface on which the 1 st light is incident and a main surface forming a 1 st light emitting surface from which the scattered light is emitted,

the light incident surface is formed on an end surface constituting a 1 st end portion of the main surface,

the diffuser functions as a light guide path for the incident 1 st light to reciprocate between the scattering layer and the transmission layer,

the scattering layer includes a nano-scale optical medium, the incident 1 st light is scattered by the nano-scale optical medium to generate the scattered light,

the scattered light has a correlated color temperature higher than that of the 1 st light.

2. The diffuser of claim 1,

the transmissive layer and the scattering layer are optically connected.

3. The diffuser of claim 1 or 2,

the transmission layer and the scattering layer are laminated in an axial direction parallel to a normal direction of the 1 st light exit surface.

4. The diffuser of any one of claims 1 to 3,

the difference in refractive index at line D between members constituting an interface existing between the scattering layer and the transmission layer is 0.5 or less.

5. The diffuser of any one of claims 1 to 4,

among the members constituting the interface between the scattering layer and the transmission layer, when a member on the incident side at the interface where the main light of the 1 st light first reaches is a 1 st member, a member on the emission side is a 2 nd member, the refractive index at the D line of the 1 st member is n1, the refractive index at the D line of the 2 nd member is n2, and R is n2/n1, 0.98 ≦ R ≦ 1.37 is satisfied.

6. The diffuser of any one of claims 1 to 5,

the diffuser is configured to guide the 1 st light to the light-guiding path, wherein the 1 st light is incident from the transmission layer to the scattering layer and from the scattering layer to the transmission layer via an interface between the transmission layer and the scattering layer, and the 1 st light is reflected by a surface facing the interface at each layer and guided to an end surface corresponding to the light-incident surface.

7. The diffuser of claim 6,

the reflection at the surface opposite to the interface is total reflection.

8. The diffuser of any one of claims 1 to 7,

the mean free path of the incident 1 st light is longer than the mean free path of light incident on a light exit body of the same size as the diffuser, which is composed of only a scattering layer having the same optical characteristics as the scattering layer, under the same conditions as the 1 st light.

9. The diffuser of any one of claims 1 to 8,

the nanoscale optical medium is a nanoparticle or composition having a nanoscale size, a pore, a concave portion on a surface, or a convex portion on a surface.

10. The diffuser of any one of claims 1 to 9,

the member constituting the scattering layer is coated on a surface of the base material constituting the transmission layer.

11. The diffuser of any one of claims 1 to 10,

the diffuser includes 2 or more regions of the major surface differing in the areal concentration of the nanoscale optical medium.

12. The diffuser of claim 11,

and a region having a smaller area concentration of the optical medium of nanometer order than other regions is included at a 2 nd end portion different from the 1 st end portion.

13. A lighting unit, characterized in that the lighting unit has:

a diffuser as claimed in any one of claims 1 to 12; and

a light source emitting the 1 st light.

14. An illumination device, characterized in that the illumination device has:

the lighting unit of claim 13; and

a frame body supporting the illumination unit.

15. The lighting device of claim 14,

the rear plate is provided as an opaque structure on the opposite side of the 1 st light emitting surface of the diffuser in the emission direction, which is the direction in which the scattered light is emitted.

16. The lighting device of claim 14 or 15,

an insolation expression unit including a light emitting surface for reproducing insolation is provided on the 1 st light emitting surface of the diffuser on the emission direction side which is a direction in which the scattered light is emitted.

17. The lighting device according to any one of claims 14 to 16,

the diffuser has a 2 nd light emitting surface which is disposed to face the light incident surface and emits light guided in the diffuser,

the lighting device further includes a light extraction unit that deflects the light emitted from the 2 nd light emission surface toward a space facing the 1 st light emission surface.

Technical Field

The invention relates to a diffuser, a lighting unit and a lighting device.

Background

As an example of an illumination device simulating a natural sky, there is an illumination system described in patent document 1. The lighting system described in patent document 1 includes a 1 st light source (2) and a lamp-like structure (10). The lamp-shaped structure (10) comprises a screen structure (14) and a bottom body (12), and the bottom body (12) is provided with a diffused light generating body (20). The diffused light generator (20) functions as a Rayleigh diffuser, substantially does not absorb in the visible light region, and diffuses wavelengths shorter than the long-wavelength component of the impinging light more efficiently. The 1 st light source (2) and the lampshade-like structure (10) are arranged in a dark box (16). The 1 st light source (2) is provided at a position offset in the vertical direction and the horizontal direction with respect to the center of the diffused light generator (20), and irradiates the upper surface of the diffused light generator (20) with an angle of about 60 degrees as a principal ray as a whole.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2015-207554

Disclosure of Invention

Problems to be solved by the invention

However, the illumination system described in patent document 1 has a problem that the 1 st light source (2) emitting strong directional light must be disposed at a position offset in the vertical direction and the horizontal direction with respect to the center of the diffused light generating body (20), and the thickness of the illumination device increases.

As a method for realizing a thin illumination device, it is effective to make light incident from an end of a diffuser (for example, the diffused light generator (20) or the like) that generates rayleigh scattering. However, in this structure, light having a high correlated color temperature is preferentially scattered during the period in which the light is guided. Therefore, color unevenness may occur on the emission surface depending on the light guiding distance in the diffuser.

In addition, if the particle concentration is reduced to reduce the scattering probability in the light guiding path, color unevenness can be reduced. However, in an illumination device that reproduces a color tone of a natural sky such as a blue sky (e.g., a transparent blue sky) by rayleigh scattering, it is necessary to adjust light by emitted scattered light so that a light emitting surface appears to be a natural sky, instead of diffusing or scattering only incident white light such as so-called white illumination. More specifically, in a light emitter that generates rayleigh scattering (for example, the diffused light generator (20) described above), it is necessary to scatter light of a blue wavelength at an appropriate ratio with respect to light of other wavelengths. This is because, by such dimming, the light exit body can be seen as a luminous body of a color tone of natural (having a profound feeling) sky.

In view of the above circumstances, an object of the present invention is to provide a diffuser, an illumination unit, and an illumination device that are thin and can suppress both reproducibility of the sky and color unevenness.

Means for solving the problems

The diffuser of the present invention is a diffuser which is formed by laminating a diffusion layer which exhibits a predetermined scattering ability with respect to the 1 st light and a transmission layer which transmits the 1 st light, and which has a light incident surface which is formed on an end surface constituting a 1 st end portion of the main surface and a main surface which forms a 1 st light emitting surface which emits the scattered light, and which is characterized in that the diffuser includes a nano-scale optical medium, and which generates the scattered light by scattering the incident 1 st light by the nano-scale optical medium, and the correlated color temperature of the scattered light is higher than the correlated color temperature of the 1 st light.

The lighting unit of the present invention is characterized in that the lighting unit includes: the above-mentioned diffuser; and a light source emitting a 1 st light.

In addition, the lighting device of the present invention is characterized by comprising: the above-described illumination unit; and a frame body supporting the illumination unit.

Effects of the invention

According to the present invention, it is possible to provide a diffuser, an illumination unit, and an illumination device that are thin and can suppress both reproducibility of the sky and color unevenness.

Drawings

Fig. 1 is a perspective view showing a schematic configuration of a lighting device according to embodiment 1.

Fig. 2 is a sectional view showing a schematic configuration of the lighting device according to embodiment 1.

Fig. 3 is a configuration diagram showing a schematic configuration of a light source according to embodiment 1.

Fig. 4 is a configuration diagram showing an example of arrangement of the light source in embodiment 1.

Fig. 5 is a perspective view showing an example of the diffuser of embodiment 1.

Fig. 6 is a perspective view showing an example of the diffuser of embodiment 1.

Fig. 7 is an explanatory view showing an example of guiding light Li and an example of generating light Ls in the diffuser in embodiment 1.

Fig. 8 is an explanatory diagram showing a relationship between an incident angle θ 2 and an output angle θ 3 of light at an interface of the 2-layer laminated structure.

Fig. 9 is a graph showing a relationship between θ 1 and θ 3 of the refractive index ratio R of the laminated structure shown in fig. 8.

Fig. 10 is an explanatory view showing another example of the lighting device of embodiment 1.

Fig. 11 is an explanatory diagram illustrating an example of the housing of embodiment 1.

Fig. 12 is an explanatory diagram illustrating an example of the diffuser of embodiment 1.

Fig. 13 is an explanatory diagram illustrating an example of the diffuser of embodiment 1.

Fig. 14 is an explanatory diagram illustrating an example of the diffuser of embodiment 1.

Fig. 15 is an explanatory view showing an example of guiding light Li and an example of generating light Ls in the diffuser in embodiment 1.

Fig. 16 is an explanatory diagram showing an example of guiding light Li and an example of generating light Ls in the diffuser in embodiment 1.

Fig. 17 is an explanatory view showing an example of guiding light Li and an example of generating light Ls in the diffuser in embodiment 1.

Fig. 18 is an explanatory diagram showing an example of guiding light Li and an example of generating light Ls in the diffuser in embodiment 1.

Fig. 19 is a diagram showing an example of the angular distribution of the intensity of scattered light by rayleigh scattering of a single particle in embodiment 1.

Fig. 20 is a structural diagram showing an example of a diffuser having a 1-layer structure as a comparative example.

Fig. 21 is a cross-sectional view showing an example of the configuration of the illumination device according to modification 1.

Fig. 22 is a perspective view showing an example of the configuration of the illumination device according to modification 2.

Fig. 23 is a cross-sectional view showing an example of the configuration of the illumination device according to modification 2.

Fig. 24 is a cross-sectional view showing an example of the configuration of the illumination device according to modification 3.

Fig. 25 is a cross-sectional view showing an example of the configuration of the illumination device according to modification 3.

Fig. 26 is a cross-sectional view showing an example of the configuration of the illumination device according to modification 3.

Fig. 27 is a perspective view showing an example of the configuration of the illumination device according to modification 3.

Fig. 28 is a perspective view showing a schematic configuration of the lighting device according to embodiment 2.

Fig. 29 is a perspective view showing a schematic configuration of the lighting device according to embodiment 3.

Fig. 30 is a sectional view showing a configuration example of a diffuser according to embodiment 3.

Detailed Description

Embodiments of a diffuser, an illumination unit, and an illumination device according to the present invention will be described below with reference to the drawings. The following embodiments are merely examples, and the embodiments can be appropriately combined and appropriately modified.

In the drawings below, the scale of the dimensions may be shown differently depending on the components. In the following embodiments, for ease of explanation, coordinate axes of an xyz rectangular coordinate system are shown in the drawings. In this case, the main emission direction, which is a direction in which the scattered light simulating the sky is mainly emitted from the light emitting body, is defined as the-y-axis direction. Further, a direction closer to the traveling direction of the light incident on the light emitting body among the directions perpendicular to the main emission direction is assumed to be the z-axis direction.

Here, the main emission direction may be changed to a normal direction of the main light emitting surface of the light emitter. The main light emitting surface is a specific surface of the light emitting surfaces of the light emitting body. More specifically, the main light-emitting surface may be a surface that is a surface from which illumination light of the light emitter is emitted, and is particularly desired to be viewed as a light-emitting surface simulating the sky.

For example, if the light emitting body is a plate-shaped light emitting body, the main light emitting surface is one of 2 surfaces (hereinafter, referred to as main surfaces) connected by a side surface. Here, the plate shape is a shape having 2 main surfaces connected with side surfaces. Hereinafter, in the plate shape, one of the 2 main surfaces connected by the side surface may be referred to as a 1 st surface, and the other may be referred to as a 2 nd surface. The plate-shaped side surface may be referred to as an end surface of the main surface.

Further, for example, if the light emitting body is a rod-shaped light emitting body, the main light emitting surface is 1 or a partial region in the side surface of the cylindrical body. Here, the bar shape is a cylindrical shape in which 2 bottom surfaces are connected with 1 or more side surfaces. In addition, the rod is a general term for a cylinder. In the rod shape, the side surface (outer surface of the side surface in the case of hollow) connected to 2 bases may be referred to as a main surface and the base may be referred to as an end surface, regardless of a column or a prism. When the main light emitting surface is formed in a partial region of the main surface (side surface of the columnar body) in the rod-shaped light emitter in order to distinguish the region in the main surface, the region may be referred to as a 1 st surface, and a region on the opposite side of the main surface from the region may be referred to as a 2 nd surface. Further, for example, when a window is provided, the main light emitting surface is a surface whose normal direction faces the inside of the room.

The main light emitting surface is not limited to a flat surface, and may include a curved surface or an inclined surface, for example. The main light emitting surface may be curved or inclined, for example, or may be a combination of such a flat surface, a curved surface, or an inclined surface. In the case where the main light emitting surface is other than the flat surface, the normal direction of the main light emitting surface may be the normal direction of the center portion or the normal direction of the tangential plane. In addition, when the main light emitting surface forms all outer edges in the yz cross section, such as when the side surface of the cylinder is the main light emitting surface, the main emission direction may be a normal direction at an arbitrary position in the main light emitting surface. In the following embodiments, the main emission direction is regarded as one of emission directions of illumination light in the illumination device 200.

Embodiment mode 1

Embodiment 1 will be described below with reference to the drawings.

< construction of illumination device 200 >

Fig. 1 and 2 are schematic configuration diagrams showing an example of an illumination device 200 according to embodiment 1. Fig. 1 is a perspective view showing a schematic configuration of the illumination device 200, and fig. 2 is a sectional view showing the schematic configuration of the illumination device 200.

The illumination device 200 has a light source 10 and a diffuser 20 as a light exit. Further, the diffuser 20 comprises a scattering layer 30 and a transmissive layer 40.

Hereinafter, the diffuser 20 and 1 or more light sources 10 provided in a pair with the diffuser 20 may be collectively referred to as an illumination unit 100. That is, the illumination unit 100 is a structure in which the light source 10 and the diffuser 20 are paired. Although not shown, the illumination device 200 may have a housing for supporting the illumination unit 100.

For convenience of explanation, the y-axis direction is the thickness direction (vertical direction) of the diffuser 20, the z-axis direction is the lateral direction (horizontal direction), and the x-axis direction is the vertical direction (front-rear direction).

In the example shown in fig. 2, the main light emitting surface is a surface f 22. In this example, light is made incident on the end face f21 of the end portion of the configuration face f22 of the diffuser 20 in the + z-axis direction, and scattered light generated by the scattering action of the diffuser 20 (more specifically, the scattering layer 30 included in the diffuser 20) on the light is emitted from the face f22, whereby the diffuser 20 is regarded as a light emitter that emits light close to the natural sky. The main light-emitting surface may be a partial region of the surface f 22. The main light-emitting surface may be formed on the surface f 22.

Hereinafter, the light incident on the end face of the diffuser 20 is sometimes referred to as light Li. The scattered light of the pseudo sky emitted from the diffuser 20 may be referred to as light Ls, scattered light Ls, or diffused light Ls. In the following, the light guided in the diffuser 20 may be referred to as light Lt or propagation light Lt. Here, "guiding" means propagating light incident into a certain medium along a predetermined optical path in the medium. Therefore, the light Lt does not include light scattered or absorbed in the diffuser 20.

As described later, the diffuser 20 is not limited to 1 emission surface for emitting the light Ls. For example, the light Ls can be emitted from the surface f23 opposite to the surface f 22.

Light Source 10

Fig. 3 is a configuration diagram showing a schematic configuration of a light source according to embodiment 1. Fig. 4 is a configuration diagram showing an example of arrangement of the light source according to embodiment 1. The light source 10 may also be an LED light source, for example. As shown in fig. 3, the light source 10 may have a substrate 12 and an LED element 13. In the example shown in fig. 3, there are a plurality of LED elements 13. Further, the LED elements 13 are arranged on the substrate 12. Here, the LED element is an example of a light emitting element.

The light source 10 is provided to face an end surface of an end portion of the surface f22 forming the main light emitting surface of the diffuser 20. For example, the light source 10 has a light emitting surface f11 that emits light Li that becomes incident light to the diffuser 20, and the light emitting surface f11 is disposed so as to face an end surface of an end portion of the surface f22 that forms the main light emitting surface of the diffuser 20.

As shown in fig. 4, the lighting device 200 may have a plurality of light sources 10 for 1 diffuser 20. Here, the unit of the light source 10 is a unit capable of independently performing on/off control, light emission amount control, or light emission color control. In addition, the illumination device 200 may be configured to have only 1 light source 10 for 1 diffuser 20 as the illumination unit 100.

Hereinafter, a group (including 1) of light sources or light emitting elements that emit incident light that generates the light Ls simulating the sky may be collectively referred to as a light source 10 for 1 diffuser 20. In addition, although the function of the light source that emits light Li is described below using the light source 10 as a subject, the function may be regarded as a function of 1 light source or 1 light-emitting element included in the illumination unit 100, or may be regarded as a function based on a combination of a plurality of light sources or a plurality of light-emitting elements.

As an example, in the configuration example of the light source 10 shown in fig. 3, each LED element 13 in the drawing may be regarded as 1 light source 10. In this case, the configuration of the light source 10 shown in fig. 3 (i.e., the configuration including the plurality of LED elements 13) does not prevent the 1 light source 10 corresponding to each LED element 13 in the drawing from being configured. In the arrangement example of the light sources 10 shown in fig. 4, each light source 10 in the drawing may be regarded as 1 LED element 13.

The light source 10 emits light Li as incident light to the diffuser 20. The light source 10 emits, for example, white light as light Li. The light source 10 may emit light of a predetermined correlated color temperature Tci as the light Li, for example.

The correlated color temperature Tci is, for example, 6500K. Further, the correlated color temperature Tci is, for example, 5000K. The correlated color temperatures of the light emitted by the light sources 10 may be the same or different.

The color of the light Li emitted from the light source 10 may be a color other than white. For example, the lighting unit 100 can include a white light source and a green light source as the light source 10. Further, the lighting unit 100 can include a white light source, a green light source, and an orange light source as the light source 10. Furthermore, the lighting unit 100 can comprise white light sources of different color temperatures as the light source 10. For example, the lighting unit 100 can include a white light source of a high color temperature and a white light source of a low color temperature as the light source 10.

Here, the difference between the color temperature of the white of the high color temperature and the color temperature of the white of the low color temperature is, for example, 8800K. The correlated color temperature of the white color of the high color temperature is, for example, 14400K. The high-color-temperature white has a correlated color temperature of, for example, 11500K or more. The correlated color temperature of white with a high color temperature is, for example, 19000K or less. The correlated color temperature of white of a low color temperature is, for example, 5600K. The low-color-temperature white has a correlated color temperature of, for example, 5500K or more. The correlated color temperature of white with a low color temperature is, for example, 6050K or less.

In addition, the light source 10 may be disposed so as to face 1 end surface of the end portion constituting the surface f22 forming the main light emitting surface as shown in fig. 4, or may be disposed so as to face 2 or more end surfaces constituting the end portion. In this case, the light source 10 of the present embodiment is considered to function as a light source that receives light Li from the end of 1 diffuser 20.

For example, the light source 10 (more specifically, the light-emitting surface f11 thereof) may be disposed so as to face at least 1 of end surfaces of the end portions of the surface f22 forming the main light-emitting surface of the diffuser 20. For example, the light sources 10 may be arranged in plural along at least 1 of end surfaces of end portions of the surface f22 forming the main light emitting surface of the diffuser 20.

Fig. 5 and 6 are perspective views showing an example of the diffuser 20. For example, in the case where the diffuser 20 has a rectangular plate shape as shown in fig. 5 and has 4 side surfaces (end surfaces f21a, f21b, f21c, f21d in the figure) and 2 main surfaces (1 st surface f22, 2 nd surface f23 in the figure) connected to the 4 side surfaces, the light source 10 may also be configured as follows. In fig. 5, the scattering layer 30 and the transmission layer 40 are not shown in the drawing, as the number of layers, the order of layers, and the thickness of the scattering layer 30 and the transmission layer 40 in the diffuser 20 are not limited.

For example, the light source 10 may be disposed to face the end face f21a of the diffuser 20. In this case, a plurality of light sources 10 may be arranged along the end face f21a of the diffuser 20. As an example, the light source 10 may be disposed to face the end face f21a and the end face f21b of the diffuser 20. In this case, a plurality of light sources 10 may be arranged along the end faces f21a and f21b of the diffuser 20. As an example, the light source 10 may be disposed to face the side face f21a, the end face f21b, and the end face f21c of the diffuser 20. In this case, a plurality of light sources 10 may be arranged along the end face f21a, the side face f21b, and the end face f21c of the diffuser 20. As an example, the light source 10 may be disposed to face the side face f21a, the end face f21b, the end face f21c, and the end face f21d of the diffuser 20. In this case, a plurality of light sources 10 may be arranged along the end face f21a, the end face f21b, the end face f21c, and the end face f21d) of the diffuser 20.

As an example, the light source 10 may be disposed to face at least one of the end face f21a, the end face f21b, the end face f21c, and the end face f21d of the diffuser 20. In this case, a plurality of light sources 1 may be arranged along at least one of the end face f21a, the end face f21b, the end face f21c, and the end face f21d of the diffuser 20.

In addition, the shape of the diffuser 20 is not limited to a rectangular plate shape. When the diffuser 20 has another shape, for example, the positional relationship between the end face and the light source may be applied to 1 of the end faces by replacing the end face with another end face opposite to the end face or another end face adjacent to the end face. Alternatively, for example, the positional relationship between the end face and the light source may be applied to a partial region of the side face to be connected, by replacing the partial region with another partial region located at a position facing the partial region or another partial region located at a position adjacent to the partial region.

For example, in the case where the diffuser 20 has a main light emitting surface formed on a rod-shaped side surface (main surface f22 in the figure) connected by 2 bottom surfaces (end surfaces f21a, f21b in the figure) as shown in fig. 6, the light source 10 may be arranged as follows.

For example, the light source 10 may be disposed to face the end face f21a of the diffuser 20. In this case, only 1 light source 10 may be arranged on the end face f21a of the diffuser 20, or a plurality of light sources may be arranged. For example, a plurality of light sources 10 may be arranged along the outer peripheral shape of the end surface f21a or uniformly in the plane. As an example, the light source 10 may be disposed to face the end face f21a and the end face f21b of the diffuser 20. In this case, only 1 light source 10 may be arranged on each of the end face f21a and the end face f21b of the diffuser 20, or a plurality of light sources may be arranged. For example, a plurality of light sources 10 may be arranged uniformly along the outer peripheral shape of the end face f21a and the end face f21b or in the plane of the end face.

Further, for example, considering ZEB (Zero Energy Building), light obtained by guiding external light (sunlight, etc.) may be used instead of the light Li from the light source 10. In the external light guide, a light-receiving member or a light guide that takes in external light and emits the external light in a predetermined direction can be used. As the light source 10, the illumination unit 100 may also have such a light-collecting member or light guide.

Diffuser 20

Next, the diffuser 20 will be described with reference to the drawings.

As shown in fig. 2, the diffuser 20 is a structure including the scattering layer 30 and the transmission layer 40, and has at least a 1 st surface (surface f22 in the figure) forming a main light-emitting surface and an end surface (surface f21 in the figure) constituting an end of the 1 st surface.

The main light-emitting area can also be a partial area of the 1 st surface. In addition, a main light emitting surface may also be formed on the 1 st surface. The incident surface is formed at the end of the No. 1 surface. The incidence surface is formed, for example, on an end surface constituting an end portion of the 1 st surface. The incidence surface may be a partial region of the end surface. Further, the incident surface may be formed on the end surface. The incident surface is formed at an end of the diffuser 20 in the z-axis direction, for example. When the diffuser 20 has a plate shape, the end portion includes a side surface having a plate shape. In the case where the diffuser 20 has a rod shape, the end portion includes a rod-shaped bottom surface.

The diffuser 20 may further have a 2 nd surface (surface f23 in the drawing) on the opposite side of the 1 st surface. Hereinafter, the 1 st surface is sometimes referred to as a front surface f22, and the end surface is sometimes referred to as a side surface f 21. In the case of having the 2 nd surface, the 2 nd surface is sometimes referred to as a back surface f 23.

Scattering layer 30

The scattering layer 30 is a layer that exhibits a prescribed scattering power with respect to the light Li. The scattering layer 30 includes, for example, a substrate 301 and particles 302.

Particles 302 are, for example, nanoparticles. "nanoparticles" are particles having a size on the order of nanometers (nm). Generally, nanoparticles are particles having a size of 1nm to several hundred nm. The particles 302 are, for example, particles having a particle diameter of the order of nanometers.

Particles 302 may be spherical or otherwise shaped.

The diffuser 20 can contain a variety of particles 302. In this case, the particle size of the particles 302 may be set to an average particle size.

The particles 302 are, for example, inorganic oxides. Inorganic oxides, e.g. ZnO, TiO₂、ZrO₂、SiO₂、Al₂O₃And the like.

The particles 302 scatter the light Li incident into the diffuser 20 to become light Ls. The particles 302 scatter the light Lt propagating through the diffuser 20 (more specifically, through the scattering layer 30) to become the light Ls.

The substrate 301 may also include particles 302, for example. Further, the particles 302 may be added to the base material 301. The particles 302 are dispersed in the base material 301, for example.

The substrate 301 is not particularly limited, but is, for example, a transparent material. The substrate 301 need not necessarily be transparent in all wavelengths of light Li. For example, the substrate 301 may have absorption at a specific wavelength among the wavelengths of light Li.

The transmittance (straight transmittance) of the base material 301 at a light guiding distance of 5mm is preferably 90% or more, more preferably 95% or more, and still more preferably 98% or more at the design wavelength. Here, the design wavelength may be a predetermined wavelength among wavelengths of the incident light. The design wavelength is not limited to 1 wavelength, and may be a plurality of wavelengths or a wavelength (band) having a width. For example, in the case where the incident light is white light, the design wavelength may be 1 or 2 or more wavelengths among 450nm, 550nm, and 650 nm. The design wavelength may be 3 wavelengths of 450nm, 550nm, and 650 nm.

The substrate 301 is, for example, a solid. The substrate 301 may be a resin plate using a thermoplastic polymer, a thermosetting resin, a photopolymerizable resin, or the like, for example. Further, as the resin sheet, an acrylic polymer, an olefin polymer, a vinyl polymer, a cellulose polymer, an amide polymer, a fluorine polymer, a urethane polymer, a silicone polymer, an imide polymer, or the like can be used. For example, the scattering layer 30 may be formed by performing a curing process while dispersing the particles 302 in the material before curing the base material 201.

The scattering layer 30 may be formed of a porous material, an organic molecule-dispersed material, an organic-inorganic hybrid material (also referred to as an organic-inorganic nanocomposite material), or a metal particle-dispersed material, which is produced by a sol-gel method, for example. For example, the scattering layer 30 may be an organic/inorganic hybrid resin, and may be a hybrid resin of a resin and an inorganic oxide, for example. In this case, the scattering layer 30 has, as a substance corresponding to the particles 302, an inorganic oxide generated by sol-gel curing on the basis of the material containing the inorganic oxide and the base material 301 of the organic compound. In the present invention, fine pores or the like generated by such a manufacturing process are also considered as the particles 302.

In addition, the scattering layer 30 may have fine irregularities smaller than the wavelength of blue light formed on the surface of the base material 301. In this case, the scattering layer 30 has fine concave or convex portions formed on the surface of the base material 301 as the particles 302. In this case, the maximum diameter of the concave portion or the convex portion is preferably on the order of nanometers (for example, 1nm to several hundred nm).

The scattering layer 30 may have a mechanism for generating rayleigh scattering, and the particles 302 and the base material 301 may not be clearly distinguished from each other in the scattering layer 30. The base material 301 is not limited to a solid, and may be a liquid, liquid crystal, or gel.

When light Li is incident on the scattering layer 30, the scattering layer 30 guides a part of the light. When light Li is incident on the scattering layer 30, the scattering layer 30 scatters a part of the light. When light Li is incident on the scattering layer 30, the scattering layer 30 causes a part of the light to be incident on the transmission layer 40 via the interface f 50. When light Lt enters the scattering layer 30 from the transmissive layer 40 via the interface f50, the scattering layer 30 guides part of the light, scatters part of the light, and enters the transmissive layer 40 again via the interface f50, as in the case of light Li.

Transmission layer 40

The transmissive layer 40 is a layer having a transmittance for light Li. Here, "transmissivity" refers to a property of light as an object passing through the inside of the medium. Examples of having transmissivity include the case where the medium transmits. In addition, the transmittance is not limited to the case where all of the incident light passes through. For example, the transmittance also includes a case where the amount of light passing through the inside of the medium is relatively large compared to the amount of light scattered or absorbed in the inside of the medium. The transmittance in the transmissive layer 40 can be evaluated by, for example, a straight transmittance, a haze value, or a mean free path of light Lt in the diffuser 20, which will be described later.

The transmissive layer 40 guides the incident light Li as light Lt by transmitting the light Li in the layer without scattering by particles or the like. The transmissive layer 40 is formed of, for example, a member having a transmittance for light Li. For example, the transmissive layer 40 may be formed of a member having a linear transmittance per unit distance at the design wavelength which is higher than at least the members (the base material 301 including the particles 302, etc.) constituting the scattering layer 30. In addition, this does not prevent the transmissive layer 40 from being formed of, for example, the same material as the base material 301.

The transmittance of the transmissive layer 40 at a light guiding distance of 5mm is preferably 90% or more, more preferably 95% or more, and still more preferably 99% or more at the design wavelength. Here, the transmittance of the transmissive layer 40 at the light guide distance of 5mm may be changed to the transmittance of a member (for example, the above-mentioned transparent material) constituting the transmissive layer 40 at the light guide distance of 5 mm.

In addition, in the case where the transmissive layer 40 is formed of the same material as the base material 301, the transmittance of the transmissive layer 40 at the light guiding distance of 5mm is the same as the transmittance of the base material 301 at the light guiding distance of 5 mm. However, in this case, when the transmittances at the light guiding distance of 5mm are compared among the members constituting the respective layers, the transmittance of the member constituting the transmissive layer 40 is higher than the transmittance of the member constituting the scattering layer 30 (the entire layer including the particles 302). When the haze values of the members constituting the respective layers are compared with each other, the haze value of the member constituting the transmissive layer 40 is lower than the haze value of the member constituting the scattering layer 30.

The transmissive layer 40 is, for example, a solid. The transmissive layer 40 is formed of a resin film using a thermoplastic polymer, a thermosetting resin, a photopolymerizable resin, or the like, for example. As the material of the acrylic polymer, the olefin polymer, or the vinyl polymer, for example, a cellulose polymer, an amide polymer, a fluorine polymer, a urethane polymer, a silicone polymer, or an imide polymer can be used as the resin film. The transmissive layer 40 is not limited to a solid, and may be a liquid, liquid crystal, or gel.

Light guide of light Li in diffuser 20

Fig. 7 is an explanatory diagram showing an example of guiding light Li and an example of generating light Ls in the diffuser 20. In this example, the diffuser 20 is incident with the light Li emitted by the light source 10. Furthermore, the diffuser 20 guides the incident light Li. The diffuser 20 guides the incident light Li as light Lt.

More specifically, the diffuser 20 causes the light Li emitted from the light source 10 to enter from the incident surface (the end surface f21a in the example in the figure), to be guided inside as light Lt, and causes a part thereof to be scattered by the particles 302 and the like (including not only nanoparticles but also a composition having a size of a nanometer level (a sol-gel cured oxide and the like), pores, and concave or convex portions on the surface. The nanoscale optical medium is not particularly limited as long as it is an optical medium (including an interface) in which rayleigh scattering or a rayleigh scattering-type scattering phenomenon occurs in the base material 301 with respect to the light Lt.

In the diffuser 20, for example, in the case of a main surface (2 surfaces of a plate shape or a side surface of a bar shape) or a hollow bar shape, the light Lt is repeatedly reflected on the outer surface and the inner surface of the side surface and guided. The reflection here is, for example, total reflection. Further, the light Lt travels (travels) to and from the scattering layer 30 and the transmission layer 40 via the interface f50 when being guided in the diffuser 20.

As shown in fig. 7, light Li incident into the diffuser 20 goes to and from the scattering layer 30 and the transmission layer 40 as light Lt, and travels in the + z-axis direction. Then, the light Li enters the scattering layer 30 as light Lt while being guided in the diffuser 20, and a part thereof is scattered by the particles 302 and the like to become light Ls. Then, at least a part of the light Ls is emitted from the main light emitting surface.

In this way, the diffuser 20 functions as a light guide path for the incident light Li to reciprocate in the scattering layer 30 and the transmission layer 40. More specifically, the scattering layer 30 and the transmission layer 40 form a light guiding path in the diffuser 20 that enables incident light Li to be alternately incident via the interface f 50.

In addition, in order to further improve the light use efficiency, the illumination unit 100 may be configured such that the optical axis of the light source 10 is inclined with respect to the z-axis of the diffuser 20. In this way, the amount of light Lt that is transmitted only straight through the transmissive layer 40 can be reduced. As a configuration for obtaining the same effect, a notch (see reference numeral 211 in fig. 7) or a prism, which deflects at least a part of light incident into the diffuser 20 in the outer circumferential direction, may be provided in the center of the incident surface of the diffuser 20.

Laminated structure of scattering layer 30 and Transmission layer 40

In the diffuser 20 of the present embodiment, the scattering layer 30 and the transmission layer 40 are laminated in, for example, an axial direction (y-axis direction in the drawing) parallel to the normal direction of the main light emitting surface, and are optically connected to each other.

Here, "optically connected" means that there is no air interface between the scattering layer 30 and the transmission layer 40. Therefore, a layer other than air may be included between the scattering layer 30 and the transmissive layer 40. For example, an adhesive, an antireflection film, or the like may be provided between the scattering layer 30 and the transmission layer 40. The reflection preventing film may be, for example, an optical film having a function of preventing the reflection of the light Lt at the interface f 50.

In addition, an "interface" is a boundary where a uniform phase contacts another uniform phase. Further, "surface" is the interface when the "other homogeneous phase" is a gas or a vacuum. For example, when the diffuser 20 is a solid, the surface of the diffuser 20 is the outer peripheral surface (outermost surface) of the diffuser 20.

In addition, the interface f50 is not limited to 1. For example, as illustrated in fig. 16 and 17 described later, in the case where the scattering layer 30 and the transmission layer 40 have a 3-layer or more laminated structure, or the like, 2 or more interfaces f50 may be present in the diffuser 20. In this case, too, in each interface f50, the scattering layer 30 and the transmissive layer 40 are optically connected to each other. Hereinafter, the interface existing between the scattering layer 30 and the transmission layer 40 is collectively referred to as an interface f 50.

In order to suppress reflection of the light Lt at the interface f50, it is preferable that the difference in refractive index between the members constituting the interface f50 (between the member constituting the scattering layer 30 and the member constituting the transmissive layer 40 in the example in the figure) be small.

For example, the difference in refractive index at the D-line (wavelength 587.56nm) between the member constituting the scattering layer 30 and the member constituting the transmissive layer 40 is 0.5 or less. The difference in refractive index is preferably 0.35 or less, more preferably 0.2 or less, and still more preferably 0.05 or less. Here, "the refractive index of the member constituting the scattering layer 30" can be rewritten as the refractive index of the base material 301. Similarly, when the member constituting the transmissive layer 40 includes not only the above-described transparent material (hereinafter referred to as the base material 401) but also particles, additives, and the like, "the refractive index of the member constituting the transmissive layer 40" can be rewritten to the refractive index of the base material 401. This is because the "homogeneous phase" in the portion mainly constituting the interface f50 is considered to be formed by the base material in the member constituting each layer. Therefore, the above refractive index difference may be a refractive index difference at the D line (wavelength 587.56nm) between the substrate 301 and the substrate 401.

In the case where a partition member is included between the scattering layer 30 and the transmission layer 40, the refractive index difference may be changed to a refractive index difference between the partition member and a member constituting the scattering layer 30 and a refractive index difference between the partition member and a member constituting the transmission layer 40.

In order to suppress reflection of the light Lt at the interface f50, for example, the ratio R of the refractive indices at the D-line (wavelength 587.56nm) between the member constituting the scattering layer 30 and the member constituting the transmissive layer 40 may be 1 or more. Here, ns is a refractive index of a D line of a member constituting the scattering layer 30, and nt is a refractive index of a D line of a member constituting the transmissive layer 40.

In the case of a configuration other than the configuration shown in fig. 7, the ratio R may be changed to n2/n 1. Here, n1 is the refractive index of the D line of the 1 st member located on the incident side in the interface f50 where the main light Lt first reaches, and n2 is the refractive index of the D line of the 2 nd member located on the exit side of the interface f 50. In addition, "mainly" means that, when the incident surface includes the end portion of the scattering layer 30 and the end portion of the transmission layer 40, the light having a stronger light amount is the 1 st light Lt and the 2 nd light Lt, when the light directly entering the transmission layer 40 and guided is the 1 st light Lt and the light directly entering the scattering layer 30 and guided is the 2 nd light Lt.

For example, when more light Li enters the transmissive layer 40 and the light amount of the 1 st light Lt > the light amount of the 2 nd light Lt, the main light Lt becomes the 1 st light Lt. In this case, the 1 st member located on the incident side when the 1 st light Lt first reaches the interface f50 is the transmissive layer 40, and the 2 nd member located on the exit side is the scattering layer 30. In the configuration shown in fig. 7, when the incident-side member (1 st member) of the interface f50, which the main light Lt reaches first, is not the transmissive layer 40, the ratio R may be set to n2/n1 according to the above definition, or the ratio R may be set to ns/nt after the light Li described later is not directly incident on the scattering layer 30.

FIG. 8 shows the incident angle θ of the light Lt at the interface f50 of the 2-layer stacked structure₂Angle of departure theta₃An explanatory diagram of the relationship of (1). Fig. 8 also shows an incident angle θ at an end face of the laminated structure of light₁Angle of incidence with the interface₂The relationship (2) of (c). In the example shown in fig. 8, when the light Lt travels from the 1 st layer having a refractive index of n1 to the 2 nd layer having a refractive index of n2, θ is calculated₂Beyond the angle of total reflection, light Lt is reflected at the interface and propagates only through layer 1.

If the refractive index of the 1 st component (the 1 st layer above) at the initial interface f50 (n1) is lower than the refractive index of the 2 nd component (the 2 nd layer above) (n2), i.e., n1<n2, the incident angle theta of n1 → n2₂The total reflection condition of (a) disappears and total reflection does not occur at any angle of incidence. However, depending on the angle of incidence θ₂And fresnel reflection is caused, the difference in refractive index between the two components is preferably small, and therefore the ratio R is preferably not too large. As the upper limit of the ratio R, for example1.37. That is, the ratio R is preferably 1.37 or less. Further, the ratio R is more preferably 1.2 or less.

The lower limit of the ratio R is, for example, 0.89. Thus, the ratio R may be 0.89R 1.37. The ratio R is more preferably 0.95 or more, and still more preferably 1 or more. By setting the ratio R in this way, it is possible to reduce the propagation of the light Lt only in the 1 st layer, or to reduce the amount of light of such light Lt.

FIGS. 9 (a) to (c) are θ representing the ratio R of the refractive indices of the laminated structure shown in FIG. 8₁And theta₃A graph of the relationship of (a). Here, fig. 9 (a) shows θ when the ratio R is 0.89₁And theta₃A graph of the relationship of (a). Fig. 9 (b) shows θ when the ratio R is 0.95₁And theta₃A graph of the relationship of (a). Fig. 9 (c) shows θ when the ratio R is 1.0₁And theta₃A graph of the relationship of (a). In fig. 9, (d) is θ representing when the ratio R is 1.2₁And theta₃A graph of the relationship of (a).

In each of the examples shown in fig. 9, θ is obtained₁And theta₂In the relation of (3), n1 is 1.49. As shown in (c) and (d) of FIG. 9, when the ratio R.gtoreq.1, the incident angle θ with the light Li₁Regardless, as long as the light Lt reaches the interface f50, the light Lt theoretically enters the 2 nd layer without being totally reflected by the 1 st layer. On the other hand, as shown in (a) and (b) of FIG. 9, at the ratio R<In the case of 1, the smaller the ratio R, the smaller the incident angle θ of the light Li for preventing the light Lt from being totally reflected at the interface f50₁The narrower the angular range of (other than the angular range represented by β on the graph) is. In the figure, β represents θ where light Lt is totally reflected at interface f50₁The angular range of (c).

For example, in the example shown in fig. 9 (a), when the ratio R is 0.89, light incident at an angle smaller than 43 ° with respect to the normal direction of the incident surface among the light Li is totally reflected at the interface f 50. Therefore, the light source 10 needs to make incident light Li having at least a component incident at an incident angle of 43 ° or more. For example, in the example shown in fig. 9 (b), when the ratio R is 0.95, light incident at an angle smaller than 28 ° with respect to the normal direction of the incident surface among the light Li is totally reflected by the interface f 50. Therefore, the light source 10 needs to make incident light Li having at least a component incident at an incident angle of 28 ° or more. In this case, the amount of light Lt that can avoid the total reflection condition may be increased by tilting the optical axis of the light source 10 or by changing the light distribution of the light Li by providing a lens between the light source 10 and the incident surface f 21.

On the other hand, as shown in (c) and (d) of FIG. 9, when the ratio R.gtoreq.1, there is no θ where the light Lt is totally reflected at the interface f50₁The angular range of (c). Therefore, the incident angle θ of the light Li can be determined in consideration of only the total reflection condition at the main surface₁The angular range of (c). However, in the ratio R>In the case of 1, it can be considered that a part of light directly incident on the 2 nd layer (in this case, a high refractive material layer) does not enter the 1 st layer but propagates only in the 2 nd layer. In addition, if the 2 nd layer is thin, the presence of such stray light can be ignored. However, for example, the following structure may be adopted so that light is not directly incident on the high refractive material layer or so that light Li is incident in an appropriate angle range.

For example, the optical axis of the light source 10 may be tilted so that the light Li enters only the low refractive material layer. As another example, as shown in fig. 10 (a), the lens 14 may be provided between the light source 10 and the diffuser 20 to change the light distribution of the light Li so that the light Li from the light source is incident only on the low refractive material layer. The lens 14 has a function of changing the divergence angle of the light Li emitted from the light source 10, for example. The lens 14 may be integrally provided on the light emitting surface f11 of the light source 10 (the end on the incident surface side of the diffuser 20). As another example, only the incident end (side surface on the light source side, etc.) of the low refractive index material layer may be brought close to the light source 10 side. In this case, when the transmissive layer 40 is a low refractive index material layer, as shown in fig. 10 (b), the lengths in the z-axis direction may be different between the transmissive layer 40 and the scattering layer 30. More specifically, a region (reference numeral 502 in the figure) where the scattering layer 30 is not laminated may be provided at an end portion on the incident surface side of the main surface of the transmission layer 40.

In the case where the partition member is included between the scattering layer 30 and the transmissive layer 40, the ratio R may be rewritten into a ratio of refractive indices between the partition member and the member constituting the scattering layer 30 and a ratio of refractive indices between the partition member and the member constituting the transmissive layer 40, as in the case of the refractive index difference. In this case, the ratio of the refractive index of the incident-side member to the refractive index of the emission-side member may be set between the members constituting the interface.

As the laminated structure of the scattering layer 30 and the transmissive layer 40, the diffuser 20 may be produced by, for example, applying a member (for example, the base material 301 including the particles 302) constituting the scattering layer 30 to a member (for example, the base material 401) constituting the transmissive layer 40. As an example of coating, a film containing the particles 302 may be coated on the substrate 401. As another example, a solution containing a material that forms a base of the member constituting the scattering layer 30 may be dip-coated or spin-coated on the base 401, and then subjected to curing treatment such as heating or light irradiation. In addition, the above coating includes dip coating or spin coating in a sol-gel method.

For example, the diffuser 20 may be formed by applying the scattering layer 30 to one or both of the 2 main surfaces of the plate-shaped member constituting the transmissive layer 40. The diffuser 20 may be formed by applying the member constituting the transmissive layer 40 to one or both of the 2 main surfaces of the plate-shaped member constituting the scattering layer 30. The diffuser 20 may be formed by applying the scattering layer 30 to the outer surface or the inner surface of the side surface of the rod-shaped member constituting the transmissive layer 40 or to both of them. The diffuser 20 may be formed by coating the outer surface or the inner surface of the side surface of the rod-shaped member constituting the scattering layer 30 or both of them with the member constituting the transmissive layer 40. In the case of a laminated structure having 3 or more layers, these coating treatments may be repeated.

The diffuser 20 may be produced by bonding a member constituting the transmissive layer 40 and a member constituting the scattering layer 30 with an adhesive or the like, for example. Here, the adhesive is, for example, an optical adhesive.

For example, the diffuser 20 may be formed by bonding a film-like member (for example, an optical film having a thickness of 0.5mm or less) constituting the scattering layer 30 to one or both of the main surfaces of the plate-like member constituting the transmissive layer 40. The diffuser 20 may be formed by bonding a film-like member constituting the transmissive layer 40 to one or both of the main surfaces of the plate-like member constituting the scattering layer 30. The diffuser 20 may be formed by attaching a film-like member constituting the scattering layer 30 to a side surface (outer surface of the side surface in the case of being hollow) of a rod-like member constituting the transmissive layer 40. The diffuser 20 may be formed by attaching a film-like member constituting the transmissive layer 40 to a side surface (outer surface of the side surface in the case of being hollow) of a rod-like member constituting the scattering layer 30. In the case of a laminated structure having 3 or more layers, the film-attaching process can be repeated.

In addition, when the scattering layer 30 and the transmissive layer 40 show fluidity, the diffuser 20 may include a container that houses the scattering layer 30 and the transmissive layer 40. The container may be configured to stack and store the scattering layer 30 and the transmissive layer 40 in a state in which they are in contact with each other (but not mixed), or may be configured to provide a partition member between the scattering layer 30 and the transmissive layer 40 and store the members of the respective layers in a space partitioned by the partition member. The transmissive layer 40 may be configured as a part of a container that houses the scattering layer 30. For example, the diffuser 20 may be configured such that a container formed of the members constituting the transmissive layer 40 is filled with the members constituting the scattering layer 30.

For example, the diffuser 20 may be formed by performing a nano-scale embossing process on the surface of the base material 301 constituting the scattering layer 30. In this case, in the thickness direction of the base material 301, the region where the surface is subjected to the embossing processing may be regarded as the scattering layer 30, and the other region may be regarded as the transmission layer 40. In this case, the transmissive layer 40 is composed of the base material 301.

As a constituent element other than the transmission layer 40 and the scattering layer 30, the diffuser 20 may be coated with a light-transmitting functional coating such as an antireflection coating, an antifouling coating, a heat-shielding coating, or a hydrophobic coating on at least 1 surface. In consideration of the functionality (impact resistance, water resistance, heat resistance, etc.) of an illumination device that can be used as a window function by exhibiting transparency, light transmittance, etc. at the time of being thin and being extinguished, or an illumination device used in a bathroom, etc., diffuser 20 may be configured to be sandwiched between 2 transparent members (e.g., glass plates), for example. In this case, the intermediate layer of the laminated glass may be regarded as the diffuser 20, or a laminated structure including the laminated glass may be regarded as the diffuser 20. In the former case, it can be said that the diffuser 20, which is a laminated structure of the transmissive layer 40 and the scattering layer 30, further has transparent members on the 1 st surface and the 2 nd surface. On the other hand, in the latter case, the laminated glass is regarded as the transmissive layer 40, and the diffuser 20 may be configured such that the scattering layer 30 is sandwiched between the transmissive layers 40 made of 2 transparent members.

In the case where the window function and the illumination function are simultaneously realized, the frame body is preferably opened in a part of a region on the 1 st surface of the diffuser 20 where at least the main light emitting surface is formed and a region on the 2 nd surface corresponding thereto (see fig. 11). In fig. 11, reference numeral 501 denotes a region forming a main light emitting surface on the surface f22 of the diffuser 20, and reference numeral 500 denotes a housing. In this example, the housing 500 has not only the opening (hereinafter referred to as the opening 501) corresponding to the region 501 on the front surface f22 but also the opening 501 on the rear surface f 23.

Further, as shown in fig. 2, the end face f21 forming the incident face can include an end face f31 of the scattering layer 30 and an end face f41 of the transmission layer 40. In this case, the incident surface may be formed on the end surface f31 of the scattering layer 30, may be formed on the end surface f41 of the transmissive layer 40, or may be formed on the end surface f31 of the scattering layer 30 and the end surface f41 of the transmissive layer 40. In other words, the light Li may enter from the end face f31 of the scattering layer 30 of the diffuser 20, may enter from the end face f41 of the transmission layer 40 of the diffuser 20, and may enter from a region including the end face f31 of the scattering layer 30 of the diffuser 20 and the end face f41 of the transmission layer 40. In any case, the light Li may be made incident on at least the end of the scattering layer 30 or the transmission layer 40 via a member constituting the incident surface.

The diffuser 20 may have a light guide end surface (e.g., a surface f21b in fig. 7) on which the light Lt reaches, on the opposite side of the end surface on which the incident surface is formed. The light guide end surface may be formed on an end surface on the opposite side in the z-axis direction of the end surface forming the incident surface, for example. The light guide end surface may include one or both of the surface of the scattering layer 30 and the surface of the transmission layer 40, as in the case of the incident surface.

Shape of diffuser 20

Next, several examples of the shape of the diffuser 20 will be shown. The diffuser 20 is, for example, plate-shaped. In addition, the plate shape is not limited to a flat plate shape. That is, the plate shape may be a shape having a curved main surface or an inclined main surface. For example, the diffuser 20 may have a curved shape of one or both of the front surface f22 and the back surface f23 (the 1 st surface and the 2 nd surface). When the front surface f22 and the back surface f23 are curved, the curvature directions of the front surface f22 and the back surface f23 may or may not coincide with each other. For example, both surfaces may be curved surfaces of a convex shape (outwardly convex shape). Further, for example, both surfaces may be curved surfaces of concave type (inwardly convex shape). For example, one surface may be a curved surface of a convex type, and the other surface may be a curved surface of a concave type. The relationship between the front surface f22 and the back surface f23 can be used as the relationship between the opposing side surfaces, for example. The surface (including the main surface) of the diffuser 20 may include a slope, a step, a recess, a projection, and the like.

As already described, the diffuser 20 is, for example, in the shape of a rod. In addition, the bar shape is not limited to the shape shown in fig. 6 in which the length or diameter of the waist circumference (the outer edge in the cross-sectional shape of the side surface) is constant in the extending direction of the column. Here, the extending direction of the column is, for example, the z-axis direction, i.e., the so-called height direction of the column when one bottom surface of the column is the surface f21a in fig. 5. The rod shape also includes a shape corresponding to a plate shape. In this case, the bottom surface of the columnar body corresponds to the main surface of the plate shape, and a bar shape in which at least one of the bottom surfaces is a main light emitting surface may be regarded as a plate shape. In this case, from the viewpoint of thinning, the length of the diffuser 20 in the thickness direction (y direction) is smaller than the length of the diffuser in the light guide direction (z direction) of the light Lt.

When the diffuser 20 has a bar shape, the extending direction of the column is defined as the z-axis direction. The y-axis direction, which is an axial direction parallel to the main emission direction, is a normal direction of the side surface of the column (main surface of the diffuser 20). Thus, the main light emitting surface becomes at least a part of the side surface of the column. The incident surface is at least one of the bottom surfaces of the pillars.

The shape of the diffuser 20 in plan view (shape on the xz plane in the drawing, hereinafter referred to as "frontal shape") is not particularly limited. For example, the front shape of the diffuser 20 may be a rectangular shape, a polygonal shape, a circular shape, a wine vessel shape, a wound shape, another shape connecting 2 or more straight lines, a shape connecting 2 or more circular arcs, a shape connecting 1 or more straight lines and 1 or more circular arcs, or the like.

The shape of the diffuser 20 when viewed from the side (the shape on the xy plane and the shape on the yz plane in the figure, hereinafter referred to as the side shape) is also not particularly limited. For example, the diffuser 20 may have a rectangular shape, a wine-bottle shape, a wound shape, another shape in which 4 or more straight lines including 2 straight lines facing each other are connected, or a shape in which 2 or more straight lines including 2 straight lines facing each other and 2 or more arcs are connected. Here, it should be noted that the side surface as the "diffuser" does not necessarily coincide with the side surface when regarded as the "pillar" (the side surface of a general pillar).

Next, as an example, the diffuser 20 of embodiment 1 will be described as having a plate shape.

The side face f21 (end face) is for light Li emitted by the light source 10 to enter. The side surface f21 is disposed, for example, so as to face the light-emitting surface 11 of the light source 10.

The front surface f22 (1 st surface) emits the light Ls scattered by the particles 302. Further, the front surface f22 may also emit the light Lt guided within the diffuser 20. For example, light guided in the diffuser 20 and reaching an end portion facing the incident surface may be deflected at the end portion or the like, and may be emitted from the front surface f22 as light for reproducing insolation.

The back surface f23 (the 2 nd surface) may emit the light Ls scattered by the particles 302. The back surface f23 may emit the light Lt guided in the diffuser 20. For example, light guided in the diffuser 20 and reaching an end portion facing the incident surface may be deflected at the end portion or the like to be emitted from the rear surface f23 to the outside for the purpose of preventing stray light.

The back surface f23 is opposite the front surface f 22. The light Lt incident on the diffuser 20 is reflected by the front surface f22 and the back surface f23 and guided. The light Lt is guided by, for example, total reflection. For example, light Lt is guided within diffuser 20.

Further, a surface (for example, a side surface) other than the front surface f22 and the back surface f23 may emit the light Ls scattered by the particles 302. The light Lt guided in the diffuser 20 may be emitted from a surface (for example, a side surface) other than the front surface f22 and the back surface f 23.

Fig. 12 to 14 are explanatory views showing examples of the diffuser 20. In each example in the drawings, the curvature and the inclination angle in the shape may be expressed to be larger than the actual one. As shown in fig. 12 (a), the diffuser 20 may be, for example, a flat plate. Here, the flat plate shape is a shape having 2 opposing flat surfaces (surfaces f23 and f24 in the figure) connected by side surfaces.

In addition, the plate shape is not limited to a flat plate shape. For example, one or both of the 1 st surface and the 2 nd surface of the diffuser 20 may be curved. For example, the diffuser 20 may be a curved surface in which one of the 1 st surface and the 2 nd surface is convex (convex outward) and the other surface is concave (convex inward) (see fig. 12 (b) to (e)). The examples shown in fig. 12 (b) and (c) are examples of the plate-shaped diffuser 20 in which the surface f22 forming the main light emitting surface is curved in a convex shape and the surface f23 on the opposite side is curved in a concave shape. Fig. 12 (b) shows an example having curvature in the xy section and yz section, and fig. 12 (c) shows an example having curvature only in the xy section. In the example shown in fig. 12 (b), the curvature of the xy cross section and the curvature of the yz cross section may be the same or different.

Although not shown, the diffuser 20 may be configured to have a curvature in the yz cross section and not have a curvature in the xy cross section. This structure corresponds to a structure in which the incident surface is rotated by 90 ° on the xz plane and the position of the incident surface is changed in the example shown in fig. 12 (c). Note that the difference in curvature in the plane is not particularly limited, and the position of the incident surface can be changed similarly in other examples.

The examples shown in fig. 12 (d) and (e) are examples of the plate-shaped diffuser 20 in which the surface f22 forming the main light emitting surface is curved in a concave shape and the surface f23 on the opposite side is curved in a convex shape. Fig. 12 (d) shows an example having a curvature in the xy section and the yz section, and fig. 12 (e) shows an example having a curvature in the xy section.

For example, both the 1 st surface and the 2 nd surface of the diffuser 20 may be curved surfaces having a convex shape (convex outward) (see (f) and (g) of fig. 12). This example also shows an example in which the y-axis thickness of the diffuser 20 is different. Although not shown, in the example shown in fig. 12 (f) and (g), the yz cross section may have a curvature, or only the yz cross section may have a curvature.

As shown in fig. 12 (g), the diffuser 20 may have a laminated structure of 3 or more layers. In this case, the stacking order is not particularly limited. Although the example shown in fig. 12 (g) is an example in which the scattering layers 30 having a constant thickness are stacked on 2 main surfaces of the transmission layers 40 having a constant thickness, the scattering layers 30 having a constant thickness may be stacked on the main surfaces of the transmission layers 40 having a constant thickness, for example.

For example, as shown in fig. 12 (h), in the diffuser 20 having a 2-layer structure, the scattering layer 30 having a non-constant thickness may be laminated on 1 main surface of the transmission layer 40 having a constant thickness. As shown in fig. 13 (h) described later, the diffuser 20 having a constant thickness may be formed by laminating a scattering layer 30 having an uneven thickness and a transmission layer 40 having an uneven thickness. As described above, the thickness of the entire diffuser 20, the number of stacked scattering layers 30 and transmissive layers 40 in the diffuser 20, and the thickness of each layer are not particularly limited.

The example shown in fig. 12 (h) is also an example in which the 2 nd surface is flat and the 1 st surface is curved. In this way, the diffuser 20 may be formed such that one of the 1 st surface and the 2 nd surface is flat and the other surface is curved (see (a) to (f) of fig. 13).

The examples shown in fig. 13 (a) to (d) have at least the back surface f23 parallel to the xz plane. In addition, although the example shown in fig. 13 (a) is an example in which the 1 st surface located at least in the-y-axis direction has curvature in the xy section, the 1 st surface located at least in the-y-axis direction may have curvature in the xy section and yz section as in the example shown in fig. 13 (b). Although not shown, the diffuser 20 may have a curvature only in the yz section at least on the 1 st surface located in the-y axis direction.

The examples shown in fig. 13 (c) and (d) are examples of the diffuser 20 having a shape in which the 2 nd surface located in the + y axis direction is flat and the surface (side surface) of the cylinder is cut out so as to have a side surface only at the end in the z axis direction. In the example shown in fig. 13 (c) and (d), the cut-out shape is also a bar shape. In this case, the surface constituting the side surface of the columnar body before cutting may be regarded as the 1 st surface (more specifically, the front surface f22) forming the main light emitting surface of the diffuser 20, and the surface corresponding to the cut surface may be regarded as the 2 nd surface (more specifically, the rear surface f 23).

The examples shown in fig. 12 (h) and fig. 13 (a) to (e) also include an example in which the flat back surface f23 is used as a reference surface and the front surface f22 is curved or inclined with respect to the reference surface. In this way, the diffuser 20 may have at least 1 main surface including a curved surface or an inclined surface with respect to the reference surface.

Here, the reference surface is, for example, a curved or inclined surface that defines the front surface or the back surface. Specifically, the plane (xz plane in the figure) may be perpendicular to the main emission direction (y-axis direction in the figure). The reference surface is, for example, a curved or inclined surface defining a side surface. Specifically, the surface (zy plane in the figure) perpendicular to the direction (z-axis direction) closer to the traveling direction of the light entering the light emitting body out of the directions perpendicular to the main emission direction, or the surface (yz plane in the figure) perpendicular to these 2 surfaces.

The reference surface is an example based on the traveling direction of light in the diffuser 20, but may be determined based on, for example, a wall or a ceiling to which the lighting device 200 is installed. For example, the reference surface may be a surface parallel or perpendicular to a surface of a wall or a ceiling as a setting destination of the lighting apparatus 200 (setting destination surface). In addition, when the installation destination surface is a curved surface, the reference surface may be a curved surface parallel to the installation destination surface or a cut surface (in this case, the reference surface is a flat surface) in the horizontal direction or the vertical direction at a position which is the center of the main light emitting surface after installation of the plate-shaped structure having a constant thickness in the normal direction with respect to the installation destination surface. In addition, more specifically, "the surface of the diffuser 20 is inclined with respect to the reference plane" means that the length in the direction perpendicular to the reference plane within the surface of the diffuser 20 is not fixed.

The diffuser 20 is not limited to the 1 st surface and the 2 nd surface, and the side surface may include a curved surface or an inclined surface. Thus, the length in the x-axis direction and the length in the z-axis direction of the diffuser 20 may or may not be fixed, not limited to the length (thickness) in the y-axis direction.

Note that, the example shown in fig. 13 (f) is an example in which the back surface f23 is curved with the flat front surface f22 as a reference surface. In this way, the diffuser 20 may also have the back side curved or inclined. The same applies to the case where the reference surface is an installation surface.

The example shown in fig. 13 (g) is an example in which the back surface f23 is inclined with the flat front surface f22 as a reference surface. Although not shown, the diffuser 20 may have the front surface f22 inclined with the flat back surface f23 as a reference surface.

The example shown in fig. 13 (h) is an example in which the diffuser 20 having a constant thickness is formed by laminating the scattering layer 30 and the transmission layer 40 having different thicknesses. As described above, in the diffuser 20, the thicknesses of the scattering layer 30 and the transmissive layer 40 are not particularly limited.

Further, for example, as shown in fig. 14, the diffuser 20 may have a rod shape. In addition, the rod shape is not limited to the cylindrical shape shown in fig. 14 (a). For example, the shape of the wine vessel may be a prism shape, a wine vessel shape, or a wound wire shape.

As shown in fig. 14, in the case of a rod shape, the diffuser 20 may have a layer structure that is oriented in the outer circumferential direction with a core of a column (hereinafter, also referred to as a rod core) as the center. When the diffuser 20 has a rod shape, an incident surface is formed on at least one of the bottom surfaces, and a main light emitting surface is formed on at least one or at least a partial region of the rod-shaped side surfaces.

For example, the examples shown in fig. 14 (a) to (c) are examples of the bar-shaped diffuser 20 extending in the extending direction without changing the dimension of the bottom surface, that is, the bar-shaped diffuser 20 in which the size of the xy cross section is fixed in the z-axis direction. Fig. 14 (a) shows an example in which the cross-sectional shape is circular, fig. 14 (b) shows an example in which the cross-sectional shape is triangular, and fig. 14 (c) shows an example in which the cross-sectional shape is quadrangular. The examples shown in fig. 14 (d) and (e) are examples of the bar-shaped diffuser 20 in which the side surfaces are curved with respect to a straight line parallel to the bar core. Fig. 14 (d) shows an example of a wine bottle shape, and fig. 14 (e) shows an example of a winding shape.

Although not shown, the rod shape may be hollow. For example, if a space exists in a part of the rod core, the diffuser 20 has a hollow rod shape. In addition, if there is no space in the rod core portion, the diffuser 20 has a solid (non-hollow) rod shape.

In the case of a rod shape, the number of layers may be 3 or more, and the order of lamination and the thickness of each layer are not particularly limited. For example, as illustrated in fig. 14 (a) to (e), the diffuser 20 may have the transmissive layer 40 disposed near the center and the scattering layer 30 disposed around the transmissive layer. For example, as illustrated in fig. 14 (f), the diffuser 20 may have the scattering layer 30 disposed near the center and the transmissive layer 40 disposed around the center.

In each of the above examples, the emission direction of the light Ls is not limited to the-y-axis direction. For example, if the diffuser 20 is a plate shape, the light Ls can be emitted from the back surface (2 nd surface). Further, for example, if the diffuser 20 is a bar shape, the light Ls can be emitted from all the surfaces forming the side surfaces of the pillar. In this way, the diffuser 20 may have 2 or more emission directions on the xy plane. For example, the diffuser 20 may be configured such that all directions of 360 degrees in the xy plane, which are radial directions, are defined as emission directions, or only some of the directions are defined as emission directions.

For example, when the light is emitted from only one main surface in the shape of a plate, or when the light is desired to be emitted from only a partial region of the main surface in the shape of a rod, for example, by providing a light absorber or a light reflector (not shown) on a part of the surface of the diffuser 20 (more specifically, a region on the surface other than the surface or the region desired to be emitted), it is possible to prevent such unnecessary light from being emitted.

For example, the surface of the diffuser 20 may be divided into a region where light Ls is emitted (hereinafter referred to as an emission region) and a region where light Ls is not emitted (hereinafter referred to as a non-emission region), and then the non-emission region may be covered with a light reflector or a light absorber. The same applies to the diffuser 20 other than the rod shape. In this case, the light reflector or the light absorber may or may not be in contact with the non-emission region. For example, the light reflector or the light absorber may be stacked on the non-emission region on the surface of the diffuser 20, or may be provided so as to face the non-emission region on the surface of the diffuser 20.

Although not shown, a part of the light Ls scattered in the scattering layer 30 can be light that travels alternately in the scattering layer 30 and the transmission layer 40 in the diffuser 20 as with the light Lt. In this case, the light Ls also becomes light that travels inside the diffuser 20 without being emitted from the surface of the diffuser 20, and is treated as light Lt.

Another light guide example of light Li in the diffuser 20

Fig. 15 to 17 are explanatory views showing another example of guiding light Li and an example of generating light Ls in the diffuser 20 according to embodiment 1. Fig. 15 is an explanatory diagram showing another example of guiding light Li and an example of generating light Ls in the diffuser 20 in which the scattering layer 30 is present on the back surface side in the yz cross section. Fig. 16 is an explanatory diagram showing another example of guiding light Li and an example of generating light Ls in the diffuser 20 in which the transmissive layer 40 is arranged between 2 scattering layers 30 in the yz cross section. Fig. 17 is an explanatory diagram showing another example of guiding light Li and an example of generating light Ls in the diffuser 20 in which the scattering layer 30 is arranged between 2 transmissive layers 40 in the yz cross section.

Thus, even if the stacking order and the number of stacks are different, the principle of generation of the light guiding path of the light Li and the light Ls is the same as the example shown in fig. 7.

In the case of a hollow rod shape, as shown in fig. 18, a laminated structure in which the scattering layer 30 and the transmission layer 40 corresponding to 2 diffusers 20 are arranged with a hollow in between in a cross section parallel to the z axis is sufficient. In this case, the outer surface of the side surface of the pillar is a front surface f22 (the 1 st surface forming the main light-emitting surface), and the inner surface is a rear surface f23 (the 1 st surface). In each stacked structure, light guiding similar to that shown in fig. 7, 10 to 14 may be performed. Although the light Ls may enter the opposing laminated structures through a hollow space, the light Ls may be emitted from the front surface f22 by traveling in the + y-axis direction or the-y-axis direction. The arrangement of the light sources 10 is not limited to the example in which a plurality of light sources 10 are arranged along the outer peripheral shape avoiding the hollow portion of the bottom surface as shown in fig. 18, and for example, in the case where the size of the hollow portion is much smaller than the irradiation range of the light sources 10, 1 light source 10 may be arranged on the rod core.

< effects of the illumination device 200 >

Rayleigh scattering

Next, rayleigh scattering, which is one of the scattering phenomena of light, will be described with reference to fig. 19. Fig. 19 is a diagram showing an example of the angular distribution of the intensity of scattered light by rayleigh scattering of a single particle 302 according to embodiment 1.

For example, light that collides with the particles 302 is described using light Li emitted from a light source. The light that collides with the particle 302 may be light Lt guided in the diffuser 20. The longitudinal axis Z is an axis parallel to the traveling direction of the light Li. The light Li travels in the + Z-axis direction. The horizontal axis X is an axis perpendicular to the vertical axis Z.

In the case where the particle diameter of the particles is smaller than the wavelength of visible light, rayleigh scattering occurs when light collides with the particles. The wavelength of visible light is, for example, in the range of 380nm to 780 nm. Specifically, when a size parameter α represented by the particle diameter d of the particle and the wavelength λ of light satisfies the following formula (1), rayleigh scattering occurs. In the equation, "·" represents a multiplication operation.

α<<π·d/λ…(1)

In rayleigh scattering, the scattering cross-sectional area σ is a parameter indicating the probability of scattering, and has a relationship of the following formula (2) with the particle diameter d and the wavelength λ of light.

σ∝d⁶/λ⁴…(2)

According to the equation (2), the scattering cross-sectional area σ in rayleigh scattering is inversely proportional to the 4 th power of the wavelength λ of light. Therefore, in rayleigh scattering, the probability of scattering is higher as the light having a shorter wavelength is shorter. Thus, it is understood from the formula (2) that blue light is more easily scattered than red light. The wavelength λ of blue light is, for example, 450 nm. The wavelength λ of red light is 650nm, for example.

Fig. 19 shows the intensity distribution of unpolarized scattered light. The particle diameter d of the particle 302 is 100 nm. The refractive index n of the particles 302 is 1.43. The refractive index of the substrate 301 is 1.33. The wavelength of the light is 450 nm.

As shown in fig. 19, in rayleigh scattering, the scattered light is emitted in all directions. Therefore, even if light is incident from the side face f21 of the diffuser 20, light can be extracted from the front surface f22 and the back surface f23 perpendicular to the side face f 21.

Generation of scattered light simulating sky

Next, the principle of generating scattered light simulating the sky (particularly, blue sky) will be described with reference to fig. 7 and 15 to 19. As shown in fig. 7 and 15 to 18, light Li emitted from the light source 10 enters from the side face f21 of the diffuser 20. The light Li incident from the side face f21 is guided to and from the scattering layer 30 and the transmission layer 40 in the diffuser 20 as light Lt. The incident light Lt is reflected at the front surface f22 and the back surface f23 of the diffuser 20.

When a part of the light Lt propagates through the diffuser 20, the light l collides with the particles 302 and the like included in the scattering layer 30 (or the travel path is blocked by the particles 302 and the like). The light Lt colliding with the particle 302 or the like is scattered in all directions (see fig. 19).

Of the scattered light, light incident on the front surface f22 at an incident angle of not more than the critical angle exits from the front surface f22 as light Ls. The critical angle is the smallest incident angle at which total reflection occurs when light travels from a place with a large refractive index to a place with a small refractive index.

Of the scattered light, light incident on the rear surface f23 at an incident angle of not more than the critical angle is emitted from the rear surface f23 as light Ls. The critical angle is the smallest incident angle at which total reflection occurs when light travels from a place with a large refractive index to a place with a small refractive index.

In this case, according to the formula (2), the probability of scattering light with shorter wavelength in rayleigh scattering is higher. Therefore, the correlated color temperature Tcs of the scattered light is higher than the correlated color temperature Tci of the incident light. For example, the correlated color temperature Tci is the correlated color temperature of the light Li emitted by the light source 10. For example, the correlated color temperature Tcs is the correlated color temperature of the light Ls.

In the case where the light Li has a spectral distribution in the entire region of visible light, the light of blue color is preferentially scattered. The light Li is, for example, white light. The light source 10 has, for example, a white LED. Therefore, by appropriately designing the light source 10 and the diffuser 20, the light Ls becomes a correlated color temperature showing blue close to the actual sky color.

Since the amount of light Ls depends on the amount of incident light Li, the amount of light of the light source 10 to be used is appropriately selected, so that the lighting device has sufficient brightness and can reproduce a sky color. Further, by appropriately designing the scattering layer 30, the thickness of the diffuser 20 can be reduced. For example, according to the structure of the present embodiment, the thickness of the diffuser 20 can be set to 100mm or less. For example, the thickness of the diffuser 20 may be 20mm or less, or may be 10mm or less. Further, for example, the thickness of the diffuser 20 may be 5mm or less. For example, when the size (length in the Y axis direction) of the light source 10 is small, or when the light Li is light having a small irradiation range on the incident surface, such as light emitted from a laser light source or condensed spot light, the thickness of the diffuser 20 may be 1mm or less.

In the above example, the front surface is divided into 2 parts as referred to as the front surface f22 and the back surface f23, but when the bar-shaped diffuser 20 has a main light emitting surface as the entire main surface (bar-shaped side surface), the front surface f22 may be rewritten as "a region in the main surface facing in the-y axis direction" and the back surface f23 may be rewritten as "a region in the main surface facing in the + y axis direction".

Effect of suppressing color unevenness based on 2-layer Structure

Fig. 20 is a structural diagram showing an example of a diffuser 90 having a 1-layer structure as a comparative example. The diffuser 90 shown in fig. 20 has only the scattering layer 30 of the present embodiment. That is, the diffuser 90 does not have the transmissive layer 40.

In rayleigh scattering, the probability of scattering is higher for light having a shorter wavelength. Therefore, the longer the light guide distance of the light Lt guided in the diffuser 90, the shorter wavelength component is attenuated more than the longer wavelength component. Therefore, for example, the correlated color temperature of the light Ls emitted from the region close to the incident surface f21 in the front surface f22 serving as the main light emitting surface is higher than the correlated color temperature of the light Ls emitted from the region distant from the incident surface f 21. This is because the light guide distance of the light Lt is longer in the distant region than in the near region, and the number of times the light Lt is scattered while being guided to the region is large.

Therefore, in the diffuser 90, as the light guide distance becomes longer, the short-wavelength component included in the guided light Lt is attenuated, and thus, it is known that the wavelength component of the light Lt changes to the longer wavelength side. Therefore, as for the light Ls generated from the light Lt, the longer the light guiding distance, the longer the long wavelength component increases. Therefore, in the diffuser 90, color unevenness is likely to occur in the light Ls in the main light emitting surface.

The distance that light propagating in the diffuser travels without being scattered is defined as the mean free path. A short mean free path means that the light guided in the diffuser is scattered by particles and the like more frequently. In other words, a short mean free path means that the color unevenness of the diffused light emitted from the diffuser is relatively large (compared to a case where the mean free path is long). In contrast, a longer mean free path means that the number of times light guided in the diffuser is scattered by particles or the like is smaller. In other words, a longer mean free path means that the color unevenness of the diffused light emitted from the diffuser is relatively small (compared to a shorter one).

In comparison with the structure shown in fig. 20, the diffuser 20 of the present embodiment has a laminated structure in which the scattering layer 30 and the transmissive layer 40 are optically connected. Therefore, the light Lt incident from the incident surface f21 of the diffuser 20 is guided by repeating total reflection, for example, on the main surface (the surfaces f22 and f23 in the drawing) of the diffuser 20. At this time, as shown in fig. 7 and the like, the light Lt travels between the scattering layer 30 and the transmission layer 40. That is, in the diffuser 20 of the present embodiment, the light Lt incident from the incident surface f21 travels to and from the scattering layer 30 and the transmission layer 40, and is repeatedly reflected and guided by the main surface of the diffuser 20. In the light guiding in the diffuser 20, no scattering occurs during the propagation in the transmissive layer 40. That is, of the light Lt traveling through the diffuser 20, all of the light Lt traveling through the transmissive layer 40 is a free path. Thus, the mean free path of the light Li in the diffuser 20 of the present embodiment with respect to the distance from the incident surface can be made longer than the mean free path in the diffuser 90 of the comparative example that does not have the transmissive layer 40 under the same conditions of the diffuser size, the particle concentration, and the like. This means that the diffuser 20 of the present embodiment can reduce the color unevenness in the main light emission plane of the light Ls, as compared with the configuration without the transmissive layer 40.

In the case where color unevenness is to be reduced in the structure shown in fig. 20, it is necessary to limit the length of the diffuser 90 or the concentration of the particles 302 to such an extent that the color unevenness is not noticeable. Alternatively, it is necessary to have a distribution in the concentration of the particles 302 contained in the base material 301 in the traveling direction of the light Lt. Specifically, the closer to the incident surface, the lower the particle concentration is, and the farther from the incident surface, the higher the particle concentration is. In contrast, according to the configuration of the diffuser 20 of the present embodiment, the effect of reducing color unevenness is obtained regardless of the length of the diffuser 20 and the scattering ability of the scattering layer 30, and even if the particle concentration does not have a distribution.

As described above, the diffuser 20 of the present embodiment is configured to reduce the color unevenness of the light Ls compared to a configuration without the transmissive layer 40 even in a thin configuration in which light is incident from the end of the diffuser 20 and is emitted in a direction perpendicular to the traveling direction of the light.

Further, according to the configuration of the present embodiment, for example, the thickness of the illumination device 200 including the housing can be set to 100mm or less. For example, the thickness of the lighting device 200 may be 50mm or less, or may be 30mm or less.

The ratio of the scattering layer 30 to the transmission layer 40 in the light guiding path of the light Lt and the ratio of the thicknesses of the scattering layer 30 and the transmission layer 40 in the diffuser 20 associated therewith are not particularly limited. The amount of the light Lt is determined appropriately according to the desired balance between the effect of reducing color unevenness and the amount of the light Lt. For example, when it is desired to further improve the effect of reducing color unevenness, the thickness of the transmissive layer 40 may be made larger than that of the scattering layer 30. In addition, when it is desired to increase the amount of light Lt, the thickness of the scattering layer 30 may be made larger than that of the transmission layer 40. Further, the case where at least a part of the light Lt is folded back at the light guide end face and reused as the light Lt guided in the diffuser 20 is not limited to this.

Further, according to the configuration of the present embodiment, by adjusting the refractive index difference between the members constituting the interface f50, reflection of the light Lt at the interface f50 can be suppressed, and the loss of chance to become the light Ls can be prevented, so that the effect of reducing the thickness and the color unevenness can be achieved while securing the light amount of the light Ls.

Further, according to the configuration of the present embodiment, for example, by applying a coating process, a film bonding process, or a rough process to a member constituting the scattering layer 30, such as the base material 401 constituting the transmissive layer 40, a diffuser capable of emitting the light Ls can be manufactured. Therefore, productivity can be improved as compared with a structure having only the scattering layer 30.

Day and night Effect based on color Change of light Source

As described above, the lighting device 200 can include a plurality of light sources 10 having different emission colors.

For example, the illumination device 200 may dynamically change the correlated color temperature (Tci) of the light Li by controlling each light source 10. This enables the correlated color temperature (Tcs) of the light Ls to be dynamically changed. For example, the illumination device 200 may control each light source 10 to dynamically change the light amount of the light Li. This enables the amount of light Ls to be dynamically changed.

By changing the correlated color temperature and the light amount of the light Li as incident light to the diffuser 20 in this way, the color of the sky can be changed over time by an observer who sees the light Ls. Moreover, a circadian rhythm can be produced.

"circadian rhythm" is a physiological phenomenon that fluctuates over a period of about 24 hours. It is present in most organisms such as animals and plants. Also commonly referred to as a "biological clock". In a strict sense, the circadian rhythm is inherently formed. However, the correction is made by external stimuli such as light, temperature, and food intake.

Rewriting of optical characteristics

The characteristics and optical characteristics of the diffuser 20 of the present embodiment can be directly regarded as those of a diffuser having a scattering ability of a 1-layer structure (for example, the diffuser 90) except for a portion contributing to an effect of extending the mean free path based on the laminated structure.

For example, the thickness of the diffuser 20 (the thickness of the stacked structure of the scattering layer 30 and the transmission layer 40) can be directly regarded as the thickness of the diffuser 90. The same applies to other features (shape example and peripheral structure). For example, the light guide path of the light Lt in the diffuser 20 can be directly regarded as the light guide path of the light Lt in the diffuser 90. The same applies to the optical path length. For example, an average refractive index, an average transmittance, and an average haze value (for example, a value obtained by weighted-averaging values of the respective layers in accordance with a ratio of the scattering layer 30 to the transmission layer 40 in the light guiding path of the light Lt) of the diffuser 20 can be regarded as a refractive index, a transmittance, and a haze value of the diffuser 90.

In addition, the particle concentration and the scattering efficiency of the diffuser 20 may be regarded as the particle concentration and the scattering efficiency of the diffuser 90 after the effect of extending the mean free path is provided.

The same applies to the opposite case. That is, the diffuser 20 of the present embodiment may also have the characteristics and optical characteristics that the diffuser 90 can have. In this case, the rewriting may be performed directly except for a portion that affects the effect of extending the mean free path based on the laminated structure, and the rewriting may be performed in consideration of the effect of extending the mean free path.

Other effects

The haze value (more specifically, the average haze value) in the thickness direction of the diffuser 20 is, for example, in the range of 0.005% to 30%. For example, when the illumination device 200 is used as a window, the haze of the diffuser 20 is suppressed within this range, and thus the window has sufficient transparency or light transmittance when the light source 10 is not lit, and when the light source 10 is lit, the color unevenness and brightness unevenness are reduced, and sufficient reproducibility of the sky color can be obtained.

The haze value is an index relating to transparency, and is obtained from the ratio of diffuse transmitted light to total light transmitted light. The haze value in the thickness direction is a ratio of diffuse transmission light emitted from the front surface f22 (or the rear surface f23) to total light transmission light when white light enters from the rear surface f23 (or the front surface f22) of the diffuser 20.

The lighting device 210 functions as a window by, for example, bringing the light source 10 into a non-lighting state in a fine day, and thus, for example, taking outside light into the room, and brings the light source 10 into a lighting state in a rainy day or a cloudy day, thereby, for example, functioning as a lighting device simulating a natural sky, and thus, providing a feeling of openness in a fine day to the room without depending on the weather.

In addition, not only in the rainy day or the cloudy day, but also in the case of strong sunshine, for example, the lighting device 210 may turn the back panel 52 off and turn the light source 10 on, thereby suppressing discomfort due to glare of sunshine and providing a feeling of opening the natural sky.

Further, according to the lighting device 200, not only is the feeling of opening the natural sky regardless of the weather provided, but also the lighting state and the non-lighting state are switched in accordance with the user operation, and thus, when the user desires to visually recognize the opposite side space, the light source can be set to the non-lighting state and the opposite side space can be visually recognized through the diffuser 20.

Further, in the lighting apparatus 200, if the diffuser 20 itself is made to be of a slide type, it is possible to simultaneously realize a function as a lighting apparatus simulating a natural sky and a window function capable of opening.

< modification 1>

Next, a modified example 1 of the illumination device of embodiment 1 will be described. In the following, the same reference numerals are given to the components common to the lighting device 200, and the description thereof will be omitted.

Fig. 21 is a cross-sectional view showing an example of the configuration of the illumination device 210 according to modification 1. The lighting device 210 has a back surface plate 52 on the basis of the light source 10 and the diffuser 20.

The back plate 52 is provided on the back surface side of the diffuser 20. The back plate 52 may be provided to face the back surface f23 of the diffuser 20. Preferably, the back plate 52 is located at a short distance from the diffuser 20.

The rear plate 52 is opaque, and the transmittance is preferably 50% or less, and more preferably 10% or less.

The back surface plate 52 is preferably a diffusion reflector, and more preferably a white diffusion reflector. The back panel 52 may also be a light absorber.

When the lighting device 210 is used as a window, the back panel 52 may be capable of changing the open/closed state. By providing the back plate 52 so as to be openable and closable, when the user desires to view the back space or to take in external light, the back plate 52 is opened, and the back space can be viewed through the diffuser 20 or external light can be taken in. The back panel 52 may be folded like a louver or a shutter, or may be stored in a window case, so that the open/closed state can be changed.

The rear plate 52 may be changed in shielding state according to a voltage applied to the rear plate 52, such as a liquid crystal shutter. The rear plate 52 may be changed in shielding state according to the voltage applied to the rear plate 52, such as a liquid crystal panel.

The back plate 52 may be supported in the housing 500 integrally with the diffuser 20. In this case, the back plate 52 may be supported so as to be openable and closable integrally with the diffuser 20.

Effect of the Back plate 52

When the light source 10 is turned on, the scattered light Ls is emitted not only from the front surface f22 but also from the rear surface f23 of the diffuser 20. For example, when the front surface f22 of the space divided by the wall on which the lighting device 210 is installed faces the side where the observer is located (hereinafter, the inside), the scattered light Ls emitted from the rear surface f23 toward the rear surface f23 (hereinafter, the outside) is lost without being visually recognized by the observer. In addition, when the illumination device 210 is used as a window, the outwardly emitted scattered light Ls may be light-damaged to people other than the observer.

By providing the rear plate 52 on the rear surface f23 side of the diffuser 20, the scattered light Ls emitted from the rear surface f23 of the diffuser 20 when the light source 10 is turned on can be prevented from being emitted outward. Further, by using a member that reflects the scattered light Ls emitted from the back surface f23, such as a diffusing reflector, as the back plate 52, the scattered light Ls emitted from the back surface f23 can be emitted from the front surface f22, and the light use efficiency of the lighting device 210 as a lighting device can be improved.

By providing the back plate 52 on the back surface side of the diffuser 20 in this way, the illumination device 210 having improved light utilization efficiency and the illumination device 210 having reduced light leakage to the back surface side can be realized.

< modification 2>

Next, a modified example 2 of the illumination device of embodiment 1 will be described. In the following, the same reference numerals are given to the components common to the illumination device 200 and the illumination device 210, and the description thereof is omitted.

Fig. 22 and 23 are explanatory views showing an example of the configuration of the illumination device 220 according to modification 2. Fig. 22 is a perspective view of the lighting device 220, and fig. 23 is a sectional view of the lighting device 220.

The lighting device 220 includes the sunshine expression unit 60 and the auxiliary light source 70 in addition to the light source 10 and the diffuser 20.

The insolation expression unit 60 is provided on the front surface f22 side of the diffuser 20. The solar radiation expression unit 60 has an incident surface f61 and an exit surface f 62. The incident surface f61 is, for example, a surface on the opposite side of the insolation expression unit 60 from the viewing side. The emission surface f62 is, for example, a surface on the viewing side of the solar radiation expression unit 60. Here, the viewing side is a side to which a user positioned on the main light emitting surface side of the diffuser 20 is viewed in a state where the lighting device 220 is provided, and the opposite side to viewing is an opposite side.

For example, the solar radiation expression unit 60 may be divided into a plurality of areas (in this example, the solar radiation expression units 60a, 60b, 60c, and 60d corresponding to the sides of the rectangular window area 501) for simplicity. The division example of the sunshine expression unit 60 is not limited to the above example.

For example, when the sunshine expression unit 60 is divided into a plurality of regions for the sake of simplicity, the incidence plane f61 and the emission plane f62 may be divided into a plurality of regions by the divided sunshine expression unit 60.

In the example shown in fig. 23, the sunshine expression units 60 are divided into 4, and are referred to as sunshine expression units 60a, 60b, 60c, and 60d, respectively. In this case, the incident surface f61 and the exit surface f62 may be divided into 4. Hereinafter, the incident surface of the insolation expression unit 60a is referred to as f61a, and the emission surface is referred to as f62 a. Similarly, the incident surface of the solar radiation expression unit 60b is referred to as f61b, the emission surface is referred to as f62b, the incident surface of the solar radiation expression unit 60c is referred to as f61c, the emission surface is referred to as f62c, the incident surface of the solar radiation expression unit 60d is referred to as f61d, and the emission surface is referred to as f62 d.

The auxiliary light source 70 is provided on the rear side of the solar radiation expression unit 60 (on the opposite side to the viewing side from the user). That is, the insolation expression unit 60 is provided with the auxiliary light source 70 on the incident surface 61 side. For example, the auxiliary light source 70 may be provided between the solar radiation expression unit 60 and the diffuser 20.

In the case where the sunshine expression unit 60 is divided into a plurality of regions for the sake of simplicity, the sunshine expression unit 60 includes the auxiliary light source 70 on the incident surface f61 side of at least one region.

The auxiliary light source 70 is, for example, an LED light source. Although not shown, the auxiliary light source 70 may include the substrate 72 and the LED element 73, as in the light source 10. In addition, the auxiliary light source 70 may be provided in plurality. In this case, the auxiliary light sources 70 may be arranged on the substrate 72, for example, as in the light source 10. In this case, it can be considered that a plurality of auxiliary light sources 70 are provided.

For example, when the insolation expression unit 60 is divided into a plurality of regions, at least 1 auxiliary light source 70 may be disposed in each region. For example, 2 or more auxiliary light sources 70 may be disposed in each region. For example, when the solar radiation expression unit 60 is provided so as to divide the polygonal window area 501, a plurality of auxiliary light sources 70 may be provided along each side of the window area 501.

The correlated color temperatures of the light emitted by the light sources may be the same or different.

The color of the light emitted from the auxiliary light source 70 may be a color other than white. When a plurality of auxiliary light sources 70 are provided, the auxiliary light sources 70 may include, for example, a white LED light source and an orange LED light source. The auxiliary light source 70 can include, for example, a white LED light source of a low color temperature and a white LED light source of a high color temperature.

The insolation expression unit 60 is made of, for example, a light diffuser. The light diffuser may be a light diffuser obtained by dispersing fine particles in the transparent member, or a light diffuser obtained by subjecting the surface of the transparent member to a surface treatment such as embossing.

The solar radiation expression unit 60 may be composed of, for example, a transparent member and a light diffuser. In this case, the light diffuser may be provided on the incident surface side of the transparent member, may be provided on the exit surface side, or may be provided on both sides. The light diffuser may be a film coating layer composed of a transparent base material and fine particles, or a diffusion sheet composed of a transparent base material and fine particles. The sunshine expression part 60 may be formed by coating or laminating such a light diffuser on the surface of the transparent member.

The light emitted from the auxiliary light source 70 enters the solar radiation expression unit 60 from the entrance surface f61 provided in the solar radiation expression unit 60, and is emitted as diffused light from the exit surface f 62. Thereby, the emission surface f62 of the insolation expression unit 60 emits light.

The insolation expression unit 60 may emit light over the entire emission surface f62, or may emit light only in a partial region. When the sunshine expression unit 60 is divided into a plurality of regions, light may be emitted for each region. The sunshine expression unit 60 may be configured to emit light in all regions, or may be configured to emit no light in some regions. The sunshine expression unit 60 may be configured to control lighting of a plurality of light sources provided as the auxiliary light source 70, for example, so that a part of the sunshine expression unit 60 is in a non-light emitting state. The sunshine expression unit 60 may emit light only in a part of the 1 region.

Further, the lighting device 220 may further include a back plate 52, as in the lighting devices 200 and 210.

Effect of solar radiation display section 60

By providing the sunshine expression unit 60 capable of emitting light on the emission side of the main light emitting surface of the diffuser 20, the observer has the following illusion: as if there is the sun on the back side of the diffuser 20, the sunshine of the sun is irradiated to the window frame. This improves the natural feeling felt by the observer when the lighting device 220 functions as lighting, and improves the sense of openness of the space. Further, by making the appropriate portion where sunlight is not irradiated non-luminous like an actual window, the natural feeling felt by the observer when the illumination device 220 functions as illumination is further improved.

< modification 3>

Next, a modified example 3 of the illumination device of embodiment 1 will be described. In the following, the same reference numerals are given to the components common to the illumination device 200, the illumination device 210, and the illumination device 220, and the description thereof will be omitted.

Fig. 24 to 27 are explanatory views showing an example of the configuration of the illumination device 230 according to modification 3. Fig. 24 to 26 are sectional views showing examples of the illumination device 230, and fig. 27 is a sectional view showing an example of the illumination device 230.

The illumination device 230 has a light folding portion 80 in addition to the light source 10, the diffuser 20, and the insolation expression portion 60.

The light folding portion 80 is provided on the side surface f21 of the diffuser 20. The light folding portion 80 is provided on at least one side surface f21 of the diffuser 20. The light folding portion 80 emits the light Lt guided in the diffuser 20 and reaching the light folding portion 80 toward the insolation expression portion 60. The light folding portion 80 changes the traveling direction of the light Lt. The light returning section 80 is an example of the deflecting section 80. Note that, although a broken-line arrow parallel to the Z-axis direction is shown as an arrow indicating the traveling direction of the light Lt in fig. 24 to 26, the light is guided in the same manner as in the above-described embodiment. That is, in this example, the light Lt is guided in the diffuser 20, and also travels to and from the scattering layer 30 and the transmission layer 40.

The light folding portion 80 may have a reflection surface f 81. In this case, the light folding unit 80 reflects the light reaching the light folding unit 80 toward the insolation expression unit 60 on the reflection surface f 81. The light refracting part 80 may have a function of changing the traveling direction in which light reaching the end surface opposite to the incident surface can be emitted toward the insolation expression part 60, and the specific form is not limited to the example shown in fig. 24.

The light whose traveling direction is changed by the light folding unit 80 is irradiated to the incident surface f61 of the insolation expression unit 60. This light enters the insolation expression unit 60 from the incident surface f61, exits from the exit surface f62, and becomes diffused light simulating insolation.

The reflecting surface f81 is a mirror surface, for example. The reflecting surface f81 is, for example, a diffuse reflecting surface. The reflecting surface f81 is provided by, for example, metal vapor deposition. The reflection surface f81 is provided by white coating, for example.

The light folding portion 80 may be formed by cutting a part of the side surface f21 of the diffuser 20, for example. At this time, the cut surface becomes the reflection surface f 81. The end of the diffuser 20 including the cut surface serves as a light folding portion 80. In this way, the diffuser 20 may include the light folding portion 80.

The light returning section 80 may be integrated with the diffuser 20 or may be separate.

In the illumination device 230, the auxiliary light source 70 may be further provided on the incidence surface f61 side of the solar radiation expression unit 60. The auxiliary light source 70 increases the amount of light emitted from the sunshine expression part 60.

The illumination device 230 and the other illumination devices may have the light sources 10 on 2 or more end surfaces. In this case, the illumination device may have the light source 10 on the opposite end surface, for example. In this case, for example, as shown in fig. 26, the illumination device 230 may be arranged such that the incident surface of the diffuser 20 and the light returning section 80 (reflection surface f81) alternate at the same end surface and alternate between the opposing end surfaces at the opposing end portions of the diffuser 20.

In addition, the incident surface of the diffuser 20 and the light returning section 80 (the reflection surface f81) are arranged along the end surface without a gap, but in this case, they may be arranged at different positions in the thickness direction of the diffuser 20. In this case, the light source 10 disposed on one end face may cause the light Li to enter so that the light Lt is guided from the entrance surface disposed on the end face to the light returning section 80 of the opposite end face.

Although not shown, 2 or more illumination units 100 may be stacked so that the traveling direction of light Li is different. In this way, the light sources 10 can be arranged in any 2 or more orientations with respect to the center of the diffuser 20. In this case, a plurality of light sources 10 may be provided corresponding to the region where the solar radiation expression unit 60 is provided.

Effect of light refracting portion 80

The light reflected by the light folding portion 80 is emitted from the insolation expression portion 60, and thus, the light guided by the diffuser 20 and emitted from the side surface f21 to be lost can be used, thereby improving the light use efficiency.

Further, for example, when the thickness of the illumination device 230 is not allowed to be increased by the presence of the insolation expression unit 60, the folded-back unit 80 may also serve as the insolation expression unit 60. For example, by providing the folded portion 80 on the side surfaces f21a, 21c, and 21d of the diffuser 20, the light folded portion 80 can also serve as the solar radiation expression portion 60. Fig. 27 is a perspective view showing an example of the illumination device 230 in which the light folding portion 80 (at least the reflection surface f81) also serving as the insolation expression portion 60 is provided on the side surface of the diffuser 20.

When the light returning section 80 also serves as the insolation expression section 60, the light returning section 80 may have a light scattering function in addition to the deflecting function. The light scattering function may be realized by applying a surface treatment such as embossing to the reflecting surface f 81. The light scattering function can be realized by, for example, adding a film having a reflection/diffusion property to the reflection surface f81 or by applying white paint. The light scattering function can be realized by including particles between the reflection surface f81 and the emission surface, for example. Further, the particles may be the particles 302 of the diffuser 20. In this case, it can be also expressed that the diffuser 20 also serves as the light folding section 80 and the insolation expression section 60. The diffuser 20 may include the light folding portion 80 and the insolation expression portion 60 as components.

The light returning section 80 may have a light scattering function for an emission surface (corresponding to an end of the front surface f22 of the diffuser 20 when formed integrally with the diffuser 20) from which the returned light is emitted, and hereinafter, referred to as an emission surface f82 when a region from which the returned light is emitted is shown. The light scattering function may be realized by applying a surface treatment such as embossing or coating with light diffusibility to the exit surface f82, or by applying a film with light diffusibility.

Although the example shown in fig. 27 is an example in which the folded portions 80 are provided on 3 side surfaces, the light folded portions 80 may be provided on all end surfaces by realizing the reflection surface f81 with a half mirror or the like.

Embodiment mode 2

Fig. 28 is an explanatory diagram illustrating an example of the configuration of the illumination device 240 according to embodiment 2. The illumination device 240 includes the light source 10, the diffuser 20, and the light extraction portion 80 a. In the following, the same reference numerals are given to the components common to the illumination device 200, the illumination device 210, the illumination device 220, and the illumination device 230, and the description thereof will be omitted.

In the illumination device 240, the diffuser 20 has the light incident surface 24 as a light incident portion, the light guide diffuser portion 251, the light guide portion 252, the front surface f22 and the back surface f23 as scattered light emitting portions (1 st light emitting surface), and the 2 nd light emitting surface 26 as a propagated light emitting portion. In this example, a portion of the diffuser 20 that contains a nano-scale optical medium such as a medium and light scattering particles (hereinafter, simply referred to as particles 302) and guides incident light to be scattered by the particles 302 to generate scattered light is referred to as a light guide diffusion portion 251. In the diffuser 20, a portion that does not include the particles 302 and guides the incident light without scattering is referred to as a light guide portion 252. The light guide diffusion portion corresponds to the scattering layer 30 of the above embodiment, and the light guide portion corresponds to the transmission layer 40 of the above embodiment.

Light emitted from the light emitting surface f11 of the light source 10 enters the light incident surface 24. The light guide diffusion portion 25 includes a substrate 301 as a medium and particles 302 present in the substrate 301. The light guide diffusion portion 251 guides incident light and scatters the incident light by the particles 302, thereby generating light Ls. The diffuser 20 has, for example, a light incident surface 24 at an end portion thereof, and a 2 nd light emitting surface 26 at an end portion thereof facing the light incident surface 24. The light source 10 is disposed at an end of the diffuser 20, and light emitted from the light emitting surface f11 of the light source 10 enters the inside of the diffuser 20 including the light guide diffuser 25 from the light incident surface 24.

The light Li entering the diffuser 20 is guided as light Lt inside the diffuser 20 and then emitted from the 2 nd light emission surface 26. Alternatively, while the light Li entering the diffuser 20 is guided as the light Lt inside the diffuser 20, the light is scattered by the particles 302 included in the light guide diffusion portion 251 of the diffuser 20 to become the light Ls, and is emitted from the front surface f22 or the like as the 1 st light emission surface. The light Li incident on the diffuser 20 is guided as light Lt inside the diffuser 20 and then emitted from the 2 nd light emission surface 26. Hereinafter, the light Lt emitted from the 2 nd light emission surface 26 may be referred to as light Lo. The correlated color temperature of the light (light Lo) emitted from the 2 nd light exit surface 26 is lower than the correlated color temperature of the light (light Ls) emitted from the front surface f 22. In fig. 28, a broken-line arrow parallel to the Z-axis direction is shown as an arrow indicating the traveling direction of the light Lt, but the light is guided in the same manner as in the above-described embodiment. That is, in this example, when the light Lt is guided in the diffuser 20, the light Lt also travels in the light guide diffusion portion 251 and the light guide portion 252.

Here, at least a part of the light Lo emitted from the 2 nd light emission surface 26 is emitted in the same direction as the light Ls (in the example of fig. 28, the direction is perpendicular to the light guiding direction, and the direction faces the space side of the front surface f22 as the main emission surface) by the light extraction portion 80a provided near the 2 nd light emission surface 26. The light extraction unit 80a has a function of directing the light Lo emitted from the 2 nd light emission surface 26 in a specific direction. In the example of fig. 28, the specific direction is a direction (Y direction) perpendicular to the light guiding direction, and is a direction toward the space facing the front surface f22, for example, a direction toward the viewing side. The specific direction may be, for example, a direction (+ Y direction) perpendicular to the light guiding direction and directed toward a space (opposite side to the viewing side) facing the back surface f 23.

The light extraction portion 80a is formed with, for example, lenses, mirrors, films, surface coatings, and the like, in order to control refraction, reflection, diffusion, transmission, and the like of the outgoing light (i.e., the light Lo guided inside the light guide diffusion portion 25 and emitted from the 2 nd light exit surface 26).

Specifically, the light Lo emitted from the 2 nd light emitting surface 26 is a scattered light having a width in an angular direction, and the light extraction portion 80a may be a mirror, and a reflecting surface of the mirror may have a curvature, in order to deflect the light in a specific direction to irradiate a space (a viewing side space or the like) located in the specific direction. With this configuration, the light reflected by the light extraction portion 80a is controlled to be substantially parallel light, and can travel in a specific direction, which is a direction toward the front surface f22 side.

In order to realize a structure that does not cause glare when the light extraction portion 80a is viewed from a person positioned on the front surface f22 side, it is preferable that the light extraction portion 80a has a diffusing function, for example. In this case, the light diffused by the light extraction portion 80a can be extracted on the front surface f22 side while suppressing glare felt by a human.

The light extraction section 80a may be provided as a modification of the light folding section 80, or may be provided separately from the light folding section 80.

Embodiment 3

Fig. 29 is a sectional view schematically showing the structure of an illumination device 250 according to embodiment 3. Next, the surface concentration of the particles 302 contained in the diffuser 20a (the number of particles 302 per unit area of the main light-emitting surface [ number/mm ]) was adjusted²]Corresponding to the main light-emitting surfaceThe number of particles 302 added in the diffuser 20a in the thickness direction per position) has a distribution.

As shown in fig. 29, the lighting device 250 includes the light source 10, the diffuser 20a, and the insolation expression unit 60 defining an area 501. In the following, the same reference numerals are given to the components common to the illumination device 200, the illumination device 210, the illumination device 220, the illumination device 230, and the illumination device 240, and the description thereof will be omitted.

The illumination device 250 adopts an edge-incident system in which the light source 10 is disposed so as to face the light incident surface 24, which is a side surface located at the end of the diffuser 20 a. Fig. 30 is a sectional view showing a configuration example of the diffuser 20a according to the present embodiment. As shown in fig. 30, the diffuser 20a has a light incident surface 24, a light guide diffuser portion 251a, a light guide portion 252b, and a front surface f22 and a rear surface f23 as the 1 st light emitting surface. In this example, the light guide diffusion portion 251a and the light guide portion 252b are stacked in the Y-axis direction.

Light emitted from the light emitting surface f11 of the light source 10 enters the light incident surface 24. The light guide diffusion portion 251a includes a substrate 201 as a medium and a plurality of particles 302 present in the substrate 201. The light guide diffusion portion 251a guides incident light and scatters the incident light by the particles 302, thereby generating light Ls. The light Ls exits through the opening 501. The light guide portions 252b form an interface f50 with the light guide diffusion portion 251a in the diffuser 20 a. When the light entering the diffuser 20a is guided inside the diffuser 20, the light enters and exits the light guide diffusion portion 251a and the light guide portion 252a via the interface f 50.

The diffuser 20a may have a region 27 in which the surface concentration of the particles 302 is low in the vicinity of at least 1 side surface (see fig. 30 (a)). As shown in fig. 29, when the area of the front surface f22 of the diffuser 20a is larger than the area of the opening 501 provided in the illumination device 250, the area density of the particles 302 in the region 27 that is not visible through the opening 501 is made lower than the area density of the particles 302 in the region 28 that is visible through the opening 501, whereby light emission from the region 27 can be suppressed, and the light utilization efficiency of the entire illumination device 250 can be improved. That is, since the probability of scattering at the light guiding and scattering portion 251a existing in the region 27 that is not visually recognized through the opening 501 can be suppressed, the light use efficiency is improved for the purpose of extracting desired blue light as illumination light from incident light, or for the purpose of extracting propagating light as illumination light or light simulating sunlight at the opposite end portion of the incident surface or the like.

The region 27 may be a region not having the light guide diffusion portion 251a (see fig. 30 (b)). For example, only light guide portion 252a may be provided in region 27 that is not visible through opening 501. In this way, light emission in the region 27 can be suppressed, and the light utilization efficiency of the entire lighting device 250 can be improved.

Since the region 27 that cannot be visually recognized through the opening 501 is not used for the purpose of emitting the scattered light Ls simulating a blue sky, the length Zd in the light guiding direction (Z direction) of the diffuser 20a other than this region 27 may be set to be substantially the length of the light guiding diffuser 251 a. As described above, when the region 27 is a region having no particles 302, the light incident surface 24 may not be provided at the end of the light guide diffusion 251 a. That is, the diffuser 20a may be configured such that light enters the light guide diffusion portion 251a via the region 27, or may be configured differently from the configuration shown in fig. 29. In addition, in order to control the intensity and direction of light to be guided with high accuracy, it is more preferable that the region 27 having no particles 302 be provided at an end portion other than the end portion where the light incident surface 24 is provided. For example, when the end provided with the light incident surface 24 is the 1 st end, the region 27 is more preferably provided at the 2 nd end of the diffuser 20a different from the 1 st end. For example, when the light incident surface 24 is provided on the side surface f21a in fig. 5, the diffuser 20a may be provided with the region 27 at the end on the side surface f21b side, the end on the side surface f21c side, and the end on the side surface f21d side. For example, when the light incident surface 24 is provided on the side surface f21a and the side surface f21b in fig. 5, the diffuser 20a may be provided with the region 27 at the end on the side surface f21c side and the end on the side surface f21d side.

Even in the area of the diffuser 20a that cannot be visually recognized through the opening 501, when the above-described other applications other than the application of supplying the scattered light or the like to the illumination expression unit 60 or the light folding unit 80 to emit the light simulating the blue sky are provided, the other applications are possibleThe area 27 may be absent and the area concentration of the particles 302 may be the same as or higher than that of the other area. In other words, in the present embodiment, the surface concentration of the particles 302 in the region where suppression of generation of scattered light or no generation of scattered light is desired can be made lower than that in other regions, regardless of whether or not the particles can be visually recognized through the opening 501. In addition, the area concentration [ pieces/mm ] of the particles 302 in a certain region of the main surface²]The concentration [ number/mm ] of the particles 302 in the light guide diffusion 251a existing on the region may be changed³]。

In the above embodiments, terms such as "parallel" and "perpendicular" may be used to indicate positional relationships between members or shapes of members. They represent ranges including manufacturing tolerances, assembly variations, and the like. Therefore, when the positional relationship or the shape is described in the claims, the range including the manufacturing tolerance, the assembling variation, and the like is included.

Further, the embodiments of the diffuser, the illumination unit, and the illumination device of the present invention are described above, but the diffuser, the illumination unit, and the illumination device of the present invention are not limited to these embodiments.

Description of the reference symbols

100: lighting unit

200. 210, 220, 230, 240: lighting device

10: light source

12: substrate

13: LED component (luminous element)

14: lens and lens assembly

20. 20 a: diffuser body

f 21: side (end face)

f 22: front surface (1 st surface)

f 23: back side (2 nd surface)

f 50: interface (I)

211: cut-out part

24: light incident surface

251. 251 a: light guide diffusion part

252. 252 a: light guide part

26: 2 nd light emitting surface

27. 28: region(s)

30: scattering layer

301: base material

302: particles

40: transmissive layer

401: base material

500: frame body

501: zone (Window zone)

502: region(s)

52: back panel

60: solar radiation display unit

70: auxiliary light source

72: substrate

73: LED component (luminous element)

80: light turning back part (deflection part)

80 a: light extraction unit

f 81: reflecting surface