阅读说明：本技术 颜色转换元件 (Color conversion element ) 是由 明田孝典 本多洋介 岸田贵司 平野徹 于 2019-07-23 设计创作，主要内容包括：颜色转换元件(1)包括：基板(2)；荧光部(3),其配置于基板(2)上,接收来自外部的激光(L)并放出与该激光(L)不同的颜色的光；反射层(4),其层叠于荧光部(3)的基板(2)侧的主面,由介电体多层膜形成；以及接合部(5),其介于反射层(4)与基板(2)之间,将反射层(4)与基板(2)接合,接合部(5)在与荧光部(3)的被激光(L)照射的照射区域(R)的至少局部在俯视时重叠的位置具有使反射层(4)暴露的空气层(53)。(The color conversion element (1) comprises: a substrate (2); a fluorescent part (3) which is arranged on the substrate (2), receives an external laser beam (L) and emits light of a color different from that of the laser beam (L); a reflective layer (4) which is laminated on the main surface of the fluorescent part (3) on the substrate (2) side and is formed of a dielectric multilayer film; and a bonding section (5) which is interposed between the reflective layer (4) and the substrate (2) and bonds the reflective layer (4) and the substrate (2), wherein the bonding section (5) has an air layer (53) which exposes the reflective layer (4) at a position which overlaps at least a part of an irradiation region (R) of the fluorescent section (3) irradiated with the laser light (L) in a plan view.)

1. A color conversion element in which, in a color conversion element,

the color conversion element includes:

a substrate;

a fluorescent portion disposed on the substrate, receiving laser light from outside, and emitting light of a color different from that of the laser light;

a reflective layer laminated on the main surface of the fluorescent part on the substrate side and formed of a dielectric multilayer film; and

a bonding portion interposed between the reflective layer and the substrate to bond the reflective layer and the substrate,

the bonding portion has an air layer exposing the reflective layer at a position overlapping at least a part of an irradiation region of the fluorescent portion irradiated with the laser light in a plan view.

2. The color conversion element according to claim 1,

a recess is provided in a position on the principal surface of the substrate on the fluorescent-light-side, the position overlapping at least a part of the irradiation region in a plan view, and the air layer is provided via the recess.

3. The color conversion element according to claim 1,

a recess group formed of a plurality of recesses is provided on a main surface of the substrate on the fluorescent-light-side at a position at least partially overlapping the irradiation region in a plan view, and the air layer is provided via the recess group.

4. The color conversion element according to any one of claims 1 to 3,

the joint has a communication hole that communicates the air layer with the outside.

5. The color conversion element according to any one of claims 1 to 4,

the fluorescent portion and the reflective layer are formed in a ring shape in a plan view,

the bonding portion bonds only the outer peripheral portion of the reflective layer located outside the irradiation region to the substrate.

6. The color conversion element according to any one of claims 1 to 5,

the fluorescent portion is disposed on the substrate in a posture in which a normal direction of a main surface of the fluorescent portion on the substrate side is inclined with respect to an incident direction of the laser beam to the fluorescent portion.

7. The color conversion element according to claim 6,

the angle formed by the normal direction and the incident direction is an angle equal to or greater than a critical angle between air and the fluorescent portion.

8. The color conversion element according to any one of claims 1 to 7,

the fluorescent portion is formed by arranging a plurality of sheet-like single sheets containing at least one phosphor in a planar manner.

9. The color conversion element according to any one of claims 1 to 8,

the fluorescent moiety is embedded in the substrate so that at least a part of a side surface of the fluorescent moiety is in contact with the substrate.

Technical Field

The present invention relates to a color conversion element in which a fluorescent portion is laminated on a substrate.

Background

For example, in a phosphor wheel (color conversion element) used in a projection apparatus such as a projector, a technique of bonding a fluorescent portion and a substrate with a thermally conductive adhesive in order to improve heat dissipation has been disclosed (for example, see patent document 1). Further, by laminating a reflective layer on the principal surface of the substrate on the fluorescent portion side, the light from the fluorescent portion is reflected by the reflective layer, thereby improving the conversion efficiency.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2016-99566

Disclosure of Invention

Problems to be solved by the invention

In recent years, further improvement in conversion efficiency of color conversion of the color conversion element is desired.

Accordingly, an object of the present invention is to provide a color conversion element capable of improving conversion efficiency.

Means for solving the problems

The color conversion element according to an aspect of the present invention includes: a substrate; a fluorescent part disposed on the substrate, receiving laser light from outside, and emitting light of a color different from that of the laser light; a reflective layer laminated on the main surface of the fluorescent part on the substrate side and formed of a dielectric multilayer film; and a bonding portion interposed between the reflective layer and the substrate, the bonding portion bonding the reflective layer and the substrate, the bonding portion having an air layer exposing the reflective layer at a position overlapping at least a part of an irradiation region of the fluorescent portion irradiated with the laser light in a plan view.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the color conversion element of the present invention, the conversion efficiency can be improved.

Drawings

Fig. 1 is a schematic diagram showing a schematic configuration of a color conversion element according to an embodiment.

Fig. 2 is a sectional view obtained by observing a sectional plane including line II-II of fig. 1.

Fig. 3 is a cross-sectional view showing a schematic configuration of a color conversion element according to modification 1.

Fig. 4 is a cross-sectional view showing a schematic configuration of a color conversion element according to modification 2.

Fig. 5 is a plan view showing a schematic configuration of a color conversion element according to modification 3.

Fig. 6 is a cross-sectional view showing a schematic configuration of a color conversion element according to modification 3.

Fig. 7 is a cross-sectional view showing a schematic configuration of a color conversion element according to modification 4.

Fig. 8 is a cross-sectional view showing a schematic configuration of a color conversion element according to modification 5.

Fig. 9 is a schematic diagram showing a schematic configuration of an illumination device according to modification 6.

Detailed Description

Hereinafter, a color conversion element according to an embodiment of the present invention will be described with reference to the drawings. The embodiments described below are all preferred specific examples of the present invention. Accordingly, the numerical values, shapes, materials, constituent elements, arrangement and connection forms of the constituent elements, and the like shown in the following embodiments are examples, and the present invention is not limited thereto. Therefore, among the components of the following embodiments, components not described in the independent claims representing the uppermost concept of the present invention are described as arbitrary components.

The drawings are schematic and not necessarily strictly illustrated. In the drawings, the same constituent members are denoted by the same reference numerals.

Hereinafter, embodiments will be described.

Fig. 1 is a schematic diagram showing a schematic configuration of a color conversion element according to an embodiment. Fig. 2 is a sectional view obtained by observing a sectional plane including line II-II of fig. 1.

The color conversion element 1 is a phosphor wheel used in a projection apparatus such as a projector. In the projection apparatus, a semiconductor laser element that emits laser light L having a wavelength of blue-violet to blue (430 to 490nm) to the color conversion element 1 is provided as a light source unit. The color conversion element 1 emits white light using the laser light L emitted from the light source unit as excitation light. The color conversion element 1 will be specifically described below.

As shown in fig. 1 and 2, the color conversion element 1 includes a substrate 2, a fluorescent portion 3, a reflective layer 4, and a bonding portion 5. In fig. 1 and 2, the laser light L is indicated by dotted hatching. In the color conversion element 1, a region irradiated with the laser light L is referred to as an irradiation region R. The irradiation region R is fixed, but relatively moves in the circumferential direction on the color conversion element 1 due to the rotation of the color conversion element 1.

The substrate 2 is, for example, a circular substrate in a plan view, and has a through hole 21 formed in the center thereof. The substrate 2 is rotationally driven by a rotation shaft in the projection apparatus being attached to the through hole 21.

The substrate 2 has a thermal conductivity higher than that of the fluorescent part 3. This enables heat conducted from the fluorescent portion 3 to be efficiently released from the substrate 2. Specifically, the substrate 2 is made of Al or Al₂O₃And a metal material such as AlN, Fe, Ti, etc. The substrate 2 may be made of a material other than a metal material as long as the thermal conductivity is higher than that of the fluorescent portion 3. Examples of the material other than the metal material include Si, ceramics, sapphire, graphite, and the like.

The substrate 2 has 1 main surface 22 formed flat, and the fluorescent moiety 3 is disposed on the main surface 22 side.

The fluorescent portion 3 has a uniform wall thickness throughout. The fluorescent portion 3 includes, for example, particles (phosphor particles 34) of a phosphor excited by the laser light L to emit fluorescence in a dispersed state, and the phosphor particles 34 emit fluorescence by irradiation with the laser light L. Therefore, the first main surface 31 of the fluorescent portion 3 on the opposite side to the substrate 2 serves as a light-emitting surface. In the present embodiment, the normal direction of the second main surface 32 on the substrate 2 side of the fluorescent portion 3 substantially coincides with the incident direction of the laser light L to the fluorescent portion 3. "substantially coincident" is an expression that includes not only perfect coincidence but also an error to the extent of several percent. The first main surface 31 of the fluorescent portion 3 may be formed to have a fine uneven shape as a whole. Specifically, the surface roughness of the first main surface 31 may be larger than a predetermined value. Thus, in the fluorescent portion 3, the first main surface 31 has a low reflectance, and therefore, light extraction efficiency and light trapping efficiency can be improved.

The fluorescent part 3 is formed in a ring shape as a whole in a plan view. The fluorescent section 3 is formed by annularly arranging a plurality of sheet-like single pieces 33 having a uniform thickness. The plurality of single sheets 33 have the same shape and the same kind. Specifically, the single piece 33 is formed in a trapezoidal shape in plan view. The single sheet 33 may have any shape as long as it is a sheet. Examples of the other planar shapes of the single piece 33 include a rectangular shape, a triangular shape, and other polygonal shapes.

Adjacent single sheets 33 substantially coincide with each other at their adjacent sides. At least one phosphor particle 34 is contained in a single sheet 33. In the present embodiment, the single sheet 33 emits white light, and contains 3 kinds of phosphor particles 34, i.e., a red phosphor that emits red light, a yellow phosphor that emits yellow light, and a green phosphor that emits green light, at an appropriate ratio, by irradiation with the laser light L.

The type and properties of the phosphor particles 34 are not particularly limited, but a relatively high output laser beam L is used as excitation light, and therefore, it is desirable that the heat resistance is high. The type of the base material 35 that holds the phosphor particles 34 in a dispersed state is not particularly limited, but a base material 35 having high transparency to the wavelength of the excitation light and the light emitted from the phosphor particles 34 is desirable. Specifically, the substrate 35 may be made of glass, ceramic, or the like. The fluorescent portion 3 may be a polycrystal or a monocrystal formed of 1 kind of fluorescent material.

The reflecting layer 4 that reflects the laser light L and the light emitted from the phosphor particles 34 is laminated with a uniform thickness on the entire back surface (main surface facing the bonding portion 5) of each segment 33.

As described above, the reflective layer 4 is laminated on the back surface of each individual piece 33. That is, the reflective layer 4 is laminated on the main surface of the fluorescent section 3 on the substrate 2 side. The reflective layer 4 has a uniform wall thickness throughout. The reflective layer 4 is a dielectric multilayer film. The dielectric multilayer film is formed by alternately laminating a transparent dielectric material having a high refractive index (n is 2.0 to 3.0) and a transparent dielectric material having a low refractive index (n is 1.0 to 1.9). The dielectric multilayer film can realize desired reflection characteristics by adjusting the refractive index of the material and the thickness of the dielectric multilayer film. Specifically, in the dielectric multilayer film forming the reflective layer 4, the refractive index of the material and the thickness of the dielectric multilayer film are adjusted so that the reflectance with respect to the laser light L and the light emitted from the phosphor particles 34 is increased. The reflective layer 4 is laminated on the back surface of each individual piece 33 by, for example, sputtering, vapor deposition, or the like.

The bonding portion 5 is interposed between the reflective layer 4 and the substrate 2, and bonds the reflective layer 4 and the substrate 2. Specifically, the joint portion 5 is formed of a resin adhesive such as silicone resin. After the bonding portion 5 is applied to the main surface 22 of the substrate 2, the reflective layer 4 of each segment 33 is bonded to the bonding portion 5, and the respective segments 33 form the fluorescent portion 3 in an annular shape in a plan view on the substrate 2. In this state, the reflective layer 4 of each single piece 33 is also formed in a ring shape in plan view similarly to the fluorescent portion 3.

The joint 5 includes a first joint 51 and a second joint 52. The first and second engaging portions 51 and 52 have a uniform wall thickness. The first joint portion 51 and the second joint portion 52 are formed in concentric annular shapes arranged with a predetermined interval in the radial direction. The first joint portion 51 has a smaller diameter than the second joint portion 52, and is disposed inward of the second joint portion 52. The first bonding portion 51 bonds the inner peripheral portion of the reflective layer 4 located inward of the irradiation region R to the substrate 2.

On the other hand, the second joining portion 52 has a larger diameter than the first joining portion 51, and is disposed outside the first joining portion 51. The second bonding portion 52 bonds the outer peripheral portion of the reflective layer 4 located outward of the irradiation region R to the substrate 2.

An annular air layer 53 concentric with the first joint portion 51 and the second joint portion 52 is formed between the first joint portion 51 and the second joint portion 52. The centers of the first engaging portion 51, the second engaging portion 52, and the air layer 53 are the rotation centers of the color conversion element 1. Since the first joint 51 and the second joint 52 are each a single continuous member in the circumferential direction, the air layer 53 is sealed by the first joint 51 and the second joint 52.

The air layer 53 exposes the reflective layer 4 and the substrate 2. That is, the reflective layer 4 and the substrate 2 are in contact with air through the air layer 53.

The air layer 53 is disposed at a position overlapping at least a part of the irradiation region R in a plan view. In the present embodiment, the air layer 53 is formed to receive the entire position and size of the irradiation region R in a plan view. As described above, since the air layer 53 is annular around the rotation center of the color conversion element 1, the air layer 53 always overlaps the irradiation region R in a plan view when the color conversion element 1 rotates.

[ operation of projection apparatus ]

Next, the operation of the projection apparatus will be described.

When the laser light L is emitted from the light source of the projection apparatus, the color conversion element 1 is rotated and driven, and the laser light L is received by the fluorescent portion 3. In the fluorescent portion 3, a part of the laser light L is directly irradiated to the phosphor particles 34. A part of the laser light L not directly irradiated to the phosphor particles 34 is reflected by the reflective layer 4 and irradiated to the phosphor particles 34. The laser light L having reached the phosphor particles 34 is converted into white light by the phosphor particles 34 and emitted. A part of the white light emitted from the phosphor particles 34 is directly emitted outward from the fluorescent portion 3. Another part of the light emitted from the phosphor particles 34 is reflected by the reflective layer 4 and emitted outward from the fluorescent portion 3.

Here, in the reflective layer 4 formed of a dielectric multilayer film, there is a small amount of light transmitted through the reflective layer 4. To cope with this, an air layer 53 is provided in the joint portion 5. Specifically, as described above, the air layer 53 is disposed directly below the reflective layer 4 in the irradiation region R. The critical angle θ c in this case is expressed by the following formula (1) according to snell's law.

θc＝arcsin(n2/n1)···(1)

Here, when the refractive index n1 of the fluorescent portion 3 as the incident medium is 1.8 and the refractive index n2 of the air layer 53 as the target medium is 1.0, the critical angle θ c becomes 33.8 degrees. The thicknesses of the adhesive layer and the reflective layer 4 are very small compared to the thickness of the fluorescent portion 3 and the thickness of the air layer 53, and the influence is small, and therefore, the calculation of the critical angle θ c is ignored.

On the other hand, a case is assumed where the air layer 53 is not provided in the joint 5. That is, in the irradiation region R, the bonding portion 5 may be disposed directly below the reflective layer 4, and the reflective layer 4 may not be exposed. In this case, when the refractive index n1 of the fluorescent portion 3 as the incident medium is 1.8 and the refractive index n2 of the junction 5 as the target medium is 1.4 (refractive index when the junction 5 is made of silicone resin), the critical angle θ c becomes 51.1 degrees.

As described above, in the present embodiment, the critical angle θ c can be made smaller than in the case where the air layer 53 is not provided in the joint 5. In other words, the range of the incident angle of total reflection (90 degrees- θ c) can be increased. As described above, not only the laser light L directly enters the reflective layer 4, but also the white light emitted from each phosphor particle 34 enters the reflective layer 4. The incident angle of the white light on the reflective layer 4 is various, but if the range of the incident angle of the total reflection is increased, more white light can be totally reflected. Therefore, the reflectance of the reflective layer 4 as a dielectric multilayer film can be improved.

[ Effect and the like ]

As described above, the color conversion element 1 of the present embodiment includes: a substrate 2; a fluorescent part 3 disposed on the substrate 2, receiving laser light L from the outside and emitting light of a color different from that of the laser light L; a reflective layer 4 laminated on the main surface of the fluorescent portion 3 on the substrate 2 side and composed of a dielectric multilayer film; and a bonding portion 5 interposed between the reflective layer 4 and the substrate 2, the bonding portion bonding the reflective layer 4 and the substrate 2, the bonding portion 5 having an air layer 53 exposing the reflective layer 4 at a position overlapping at least a part of an irradiation region R of the fluorescent portion 3 irradiated with the laser light L in a plan view.

Accordingly, since the air layer 53 overlaps at least a part of the irradiation region R in a plan view, the range of the incident angle of total reflection (90 degrees — θ c) can be increased as compared with the case where the air layer 53 is not provided. Therefore, the reflectance of the reflective layer 4 as a dielectric multilayer film can be improved, and the conversion efficiency can be improved.

In particular, in the present embodiment, since the air layer 53 is formed to receive the position and size of the entire irradiation region R in a plan view, the reflectance can be improved for the entire irradiation region R. That is, the conversion efficiency can be further improved.

The fluorescent portion 3 is formed by arranging a plurality of sheet-like individual pieces 33 containing at least one kind of phosphor (phosphor particles 34) in a planar manner.

Thus, the fluorescent portion 3 is formed of a plurality of individual pieces 33 arranged in a planar shape, and therefore stress applied during heating can be dispersed. This can suppress deformation of the fluorescent portion 3 when receiving the laser light L. Therefore, the positional relationship between the fluorescent portion 3 and the air layer 53 can be stabilized, and stable reflection characteristics can be maintained.

Here, in the case of the fluorescent portion integrally formed as a whole, if the shape is annular in plan view, stress concentration is less likely to be received, and the above-described defects are likely to occur. However, when the fluorescent portion 3 is formed by annularly disposing the plurality of single pieces 33 as in the present embodiment, stress can be dispersed, and thus a high stress relaxation effect can be obtained.

In the above-described embodiment, the case where the fluorescent moiety 3 is formed of a plurality of individual pieces 33 is exemplified. However, the fluorescent portion may be an integral body integrally molded.

[ modification 1]

Next, modification 1 will be described. Fig. 3 is a cross-sectional view showing a schematic configuration of a color conversion element 1A according to modification 1, and specifically corresponds to fig. 2. In the following description, the same reference numerals are given to the same parts as those of the color conversion element 1 of the embodiment, and the description thereof is omitted, and only different parts will be described.

In the above embodiment, the case where the main surface 22 of the substrate 2 is flat is exemplified. In modification 1, a case where the concave portion 25a is formed on the main surface 22a of the substrate 2a is exemplified.

Specifically, the concave portion 25a is disposed at a position on the main surface 22a of the substrate 2a, which overlaps at least a part of the irradiation region R in a plan view. In the present embodiment, the recess 25a is formed to receive the entire position and size of the irradiation region R in a plan view. The concave portion 25a is formed in an annular shape centering on the rotation center of the color conversion element 1 in a plan view. That is, the recessed portion 25a may be referred to as a continuous groove portion having an annular shape in plan view. The recess 25a is formed in a rectangular shape in cross section. An air layer 53a is provided through the recess 25 a. The cross-sectional shape of the recess 25a may be arbitrary.

A part of the joint portion 5a flows into the concave portion 25a at the time of manufacture. The air layer 53a can be reliably formed at a position overlapping the irradiation region R in plan view by the local inflow recess 25a of the joint portion 5 a. In fig. 3, a state in which a part of the joint portion 5a flows into the entire recess 25a is shown, but the joint portion 5a may be divided in the recess 25 a. In either case, the air layer 53a exposing the reflective layer 4 can be reliably formed by the presence of the recess 25 a.

[ modification 2]

Next, modification 2 is explained. Fig. 4 is a cross-sectional view showing a schematic configuration of a color conversion element 1B according to modification 2, and specifically corresponds to fig. 2. In the following description, the same reference numerals are given to the same parts as those of the color conversion element 1 of the embodiment, and the description thereof is omitted, and only different parts will be described.

In the above embodiment, the case where the main surface 22 of the substrate 2 is flat is exemplified. In modification 1, a case is exemplified in which a concave portion group 251b formed of a plurality of concave portions 25b is formed on the main surface 22b of the substrate 2 b.

Specifically, the concave portion group 251b is disposed at a position on the main surface 22b of the substrate 2a, which overlaps at least a part of the irradiation region R in a plan view. In the present embodiment, the concave portion group 251b is formed to have a position and a size to receive the entire fluorescent portion 3 in a plan view. Therefore, the entire irradiation region R overlaps the concave portion group 251b in a plan view. An air layer 53b is provided by the concave portion group 251 b.

The concave portion group 251b is formed in an annular shape centered on the rotation center of the color conversion element 1 in a plan view. Here, each of the concave portions 25b forming the concave portion group 251b is formed in a concentric annular shape centering on the rotation center of the color conversion element 1 in a plan view. The cross-sectional shape of each concave portion 25b is formed in a triangular shape. The cross-sectional shape of each concave portion 25b may be arbitrary. The cross-sectional shape of each concave portion 25b may be different.

During manufacturing, the first joint 51b and the second joint 52b of the joint 5b are applied to the concave portion group 251 b. At this time, in the boundary portion of the air layer 53b, the mountain portion between the adjacent concave portions 25b becomes a wall, and the first joint portion 51b and the second joint portion 52b are blocked from entering inward. Therefore, the air layer 53b can be reliably ensured. Further, the first engaging portion 51b and the second engaging portion 52b are respectively formed continuously with the plurality of concave portions 25 b. That is, the contact area of the first joint portion 51b and the substrate 2b and the contact area of the second joint portion 52b and the substrate 2b can be increased. This can improve heat dissipation and adhesion, and can improve the reliability of the color conversion element 1B.

[ modification 3]

Next, modification 3 is explained. Fig. 5 is a plan view schematically showing the structure of a color conversion element 1C according to modification 3, and specifically corresponds to fig. 1. Fig. 6 is a cross-sectional view showing a schematic configuration of a color conversion element 1C according to modification 3, and specifically corresponds to fig. 2. In the following description, the same reference numerals are given to the same parts as those of the color conversion element 1 of the embodiment, and the description thereof is omitted, and only different parts will be described.

In the above embodiment, the case where the air layer 53 is sealed by the first bonding part 51 and the second bonding part 52 of the bonding part 5 is exemplified. In modification 3, a case where the air layer 53c is not sealed will be described.

Specifically, in the joint portion 5c of modification 3, a pair of communication holes 511c are formed at positions facing each other across the center of the first joint portion 51 c. The pair of communication holes 511c extend in the radial direction and penetrate the first joint portion 51 c. On the other hand, a pair of communication holes 521c are formed at positions facing each other across the center of the second joint portion 52 c. The pair of communication holes 521c extend in the radial direction and penetrate the second joint portion 52 c. The pair of communication holes 511c of the first joint 51c and the pair of communication holes 521c of the second joint 52c are arranged on the same straight line. The air layer 53c communicates with the outside through the communication holes 511c and 521 c.

Since the joint 5c has the communication holes 511c and 521c for communicating the air layer 53c with the outside, the communication holes 511c and 521c can be used as air channels. For example, even if the air in the air layer 53c is heated and expanded during the irradiation with the laser light L or during the manufacturing, the air can be released to the outside through the communication holes 511c and 521 c. That is, the shape of the air layer 53c can be kept constant. Therefore, peeling of the bonding portion 5C due to the change in shape of the air layer 53C can be suppressed, and the reliability of the color conversion element 1C can be improved. The number and the position of the through holes may be arbitrary.

[ modification 4]

Next, modification 4 will be described. Fig. 7 is a cross-sectional view showing a schematic configuration of a color conversion element 1D according to modification 4, and specifically corresponds to fig. 2. In the following description, the same reference numerals are given to the same parts as those of the color conversion element 1 of the embodiment, and the description thereof is omitted, and only different parts will be described.

In the above embodiment, the case where the bonding portion 5 bonds the outer peripheral portion of the reflective layer 4 located outward of the irradiation region R to the substrate 2 and bonds the inner peripheral portion of the reflective layer 4 located inward of the irradiation region R to the substrate 2 is exemplified. In modification 4, a case will be described in which the bonding portion 5d bonds only the outer peripheral portion of the reflective layer 4 located outward of the irradiation region R to the substrate 2.

Specifically, the joining portion 5d is formed in an annular shape in plan view so as to join the outer peripheral portion of the reflection layer 4 located outward of the irradiation region R to the substrate 2. Therefore, the entire portion inward of the joint portion 5d becomes the air layer 53 d. In this case, the space between the inner peripheral portion of the reflective layer 4 located inward of the irradiation region R and the substrate 2 can be regarded as a via hole. That is, the same effects as those in the case where the communication holes 511c and 521c are provided can be obtained.

In addition, in the case where the color conversion member 1D is a phosphor wheel, the color conversion member 1D rotates, but since the engaging portions 5D are provided only on the outer peripheral portion of the color conversion member 1D, even if a centrifugal force due to the rotation acts, a stable state can be maintained with a small number of engaging portions 5D. That is, the amount of the adhesive used can be suppressed.

[ modification 5]

Next, modification 5 will be described. Fig. 8 is a cross-sectional view showing a schematic configuration of a color conversion element 1E according to modification 5, and specifically corresponds to fig. 2. In the following description, the same reference numerals are given to the same parts as those of the color conversion element 1 of the embodiment, and the description thereof is omitted, and only different parts will be described.

In the above embodiment, the case where the first main surface 31 and the second main surface 32 of the fluorescent moiety 3 are not inclined with respect to the main surface 22 of the substrate 2 is exemplified. In modification 5, a case where the first main surface 31 and the second main surface 32 of the fluorescent moiety 3 are inclined with respect to the main surface 22e of the substrate 2e will be described. Since the fluorescent portion 3, the reflective layer 4, and the bonding portion 5 of modification 5 are the same as those of the above embodiment except for the posture thereof with respect to the substrate 2e, they are described with the same reference numerals.

Specifically, a concave portion 29e for accommodating the fluorescent portion 3, the reflective layer 4, and the bonding portion 5 is formed on the main surface 22e of the substrate 2e of modification 5. The recess 29e is formed in an annular shape centered on the rotation center in a plan view. The recessed portion 29e has a recessed shape in cross section in which the bottom surface is inclined outward with respect to the main surface 22e of the substrate 2e and the inner peripheral surface and the outer peripheral surface are orthogonal to the bottom surface. By housing the fluorescent portion 3, the reflective layer 4, and the bonding portion 5 in the recess 29e, the fluorescent portion 3, the reflective layer 4, and the bonding portion 5 are inclined with respect to the main surface 22e of the substrate 2 e. Specifically, the first joint portion 51 of the joint portion 5 is stacked on the inner peripheral portion of the bottom surface of the recess 29e, and the second joint portion 52 is stacked on the outer peripheral portion of the bottom surface of the recess 29 e. An air layer 53 is formed between the first joint 51 and the second joint 52. By laminating the reflective layer 4 and the bonding portion 5 on the first bonding portion 51 and the second bonding portion 52, the first main surface 31 and the second main surface 32 of the fluorescent portion 3 are parallel to the bottom surface of the recess 29 e. That is, the fluorescent portion 3 is embedded in the concave portion 29e in a posture inclined outward with respect to the main surface 22e of the substrate 2 e. Part of the fluorescent part 3 protrudes from the recess 29e, but the other part is embedded in the recess 29 e. The inner surface and the outer surface of the fluorescent part 3 are in contact with the substrate 2e in the recess 29 e. This allows heat to be conducted to the substrate 2e from the inner surface and the outer surface of the fluorescent portion 3.

The fluorescent portion 3 is disposed on the substrate 2e in a posture in which a normal direction N of the second main surface 32 of the fluorescent portion 3 on the substrate 2e side is inclined with respect to an incident direction I in which the laser light L is incident on the fluorescent portion 3. At this time, the angle α formed by the normal direction N and the incident direction I is equal to or larger than the critical angle θ c between the air and the fluorescent portion 3. Therefore, the laser light L is incident on the fluorescent portion 3 at an incident angle of total reflection, and thus the reflectance at the reflective layer 4 can be increased.

In this way, the fluorescent portion 3 is disposed on the substrate 2e in a posture in which the normal direction N of the main surface (second main surface 32) of the fluorescent portion 3 on the substrate 2e side is inclined with respect to the incident direction I in which the laser light L is incident on the fluorescent portion 3.

Accordingly, the normal direction N of the second main surface 32 of the fluorescent portion 3 is inclined with respect to the incident direction I of the laser light L, and therefore the laser light L can be easily totally reflected by the reflective layer 4. This increases the reflectance at the reflective layer 4, and thus can improve the conversion efficiency.

The angle α formed by the normal direction N and the incident direction I is equal to or greater than the critical angle θ c between the air and the fluorescent portion 3.

This allows the laser light L to enter the fluorescent section 3 at an incident angle of total reflection, and thus the reflectance of the reflective layer 4 can be reliably increased. Thus, the conversion efficiency can be further improved.

The fluorescent portion 3 is embedded in the substrate 2e so that at least a part of the side surface thereof is in contact with the substrate 2 e.

This allows heat to be conducted from the inner surface and the outer surface, which are the side surfaces of the fluorescent portion 3, to the substrate 2e, thereby further improving heat dissipation.

In modification 5, the case where the fluorescent portion 3, the reflective layer 4, and the bonding portion 5 are inclined outward with respect to the main surface 22e of the substrate 2e is exemplified, but these members may be inclined inward.

In modification 5, the case where the fluorescent portion 3 is inclined with respect to the main surface 22e of the substrate 2e, so that the normal direction N of the second main surface 32 on the substrate 2e side of the fluorescent portion 3 is inclined with respect to the incident direction I of the laser light L into the fluorescent portion 3 is exemplified. However, the incident direction of the laser light L may be inclined with respect to the second main surface 32 of the fluorescent portion 3 and the normal direction N may be inclined with respect to the incident direction I.

In modification 5, the fluorescent portion may be integrally molded as a single piece.

[ modification 6]

In the above embodiment, the case where the color conversion element 1 is applied to the projection apparatus is exemplified, but the color conversion element can also be applied to the illumination apparatus. In this case, the color conversion element does not rotate, and therefore may not be wheel-shaped. An example of a color conversion element applied to an illumination device is described below.

Fig. 9 is a schematic diagram showing a schematic configuration of an illumination device 100 according to modification 6. As shown in fig. 9, the illumination device 100 includes a light source section 101, a light guide member 102, and a color conversion element 1F.

The light source section 101 generates laser light L1 and supplies the laser light L1 to the color conversion element 1F via the light guide member 102. For example, the light source 101 is a semiconductor laser device that emits laser light L1 having a wavelength of blue-violet to blue (430 to 490 nm). The light guide member 102 is a light guide member that guides the laser light L1 emitted from the light source unit 101 to the color conversion element 1F, and is, for example, an optical fiber or the like.

The substrate 2F of the color conversion element 1F is rectangular in plan view, and the reflective layer 4F and the fluorescent portion 3F are laminated on one main surface 22F thereof with the bonding portion 5F interposed therebetween. The fluorescent portion 3f is formed in a rectangular shape in a plan view, and a reflective layer 4f formed of a dielectric multilayer film is laminated on the entire main surface of the substrate 2 f. The joining portion 5f is formed in a frame shape continuous with the outer peripheral edge of the fluorescent portion 3 f. Thus, an air layer 53f exposing the reflective layer 4f is formed inside the joint portion 5 f. The air layer 53f is disposed at a position overlapping the irradiation region R1 of the laser beam L1 in a plan view.

In this way, in the illumination device 100 of modification 6, the air layer 53f exposes the reflective layer 4f at a position overlapping at least a part of the irradiation region R1 of the fluorescent portion 3f in a plan view. Therefore, the range of the incident angle of total reflection (90 degrees- θ c) can be increased as compared with the case where the air layer 53f is not provided. Therefore, the reflectance of the reflective layer 4f as the dielectric multilayer film can be improved, and the conversion efficiency can be improved.

In addition, in the color conversion element applied to the illumination device, the fluorescent portion may be formed of a plurality of individual pieces.

[ other embodiments ]

The illumination device of the present invention has been described above based on the above embodiment and modifications, but the present invention is not limited to the above embodiment and modifications.

For example, a reflection suppression layer such as an AR coating layer may be laminated on the first main surface 31 on the light emission side of the fluorescent section 3. This can improve the light extraction efficiency.

In the above-described embodiment, the case where the entire fluorescent portion 3 is formed of the single piece 33 that emits white light is exemplified. However, when the fluorescent portion emits light of a plurality of colors, the portion of the fluorescent portion 3 that emits each color may be formed of a single sheet of the same kind. For example, a case is assumed where 3 layers of red, green, and blue fluorescent moieties are arranged in a planar manner. The red fluorescent moiety is formed of a plurality of single sheets of the same kind containing a red phosphor. The blue fluorescent moiety is formed of a plurality of single pieces of the same kind including the blue phosphor. The green fluorescent portion is formed of a plurality of single pieces of the same kind containing the green phosphor.

Further, embodiments obtained by applying various modifications to the embodiments as will be understood by those skilled in the art, and embodiments obtained by arbitrarily combining the constituent elements and functions of the embodiments and modified examples 1 to 3 without departing from the spirit of the present invention are also included in the present invention.

Description of the reference numerals

1. 1A, 1B, 1C, 1D, 1E, 1F, color conversion elements; 2. 2a, 2b, 2e, 2f, a substrate; 3. 3f, a fluorescent moiety; 4. 4f, a reflective layer; 5. 5a, 5b, 5c, 5d, 5f, a joint; 21. a through hole; 22. 22a, 22b, 22e, 22f, main faces; 25a, 25b, 29e, recess; 32. a second main surface (main surface); 53. 53a, 53b, 53c, 53d, 53f, an air layer; 251b, a set of recesses; 511c, 521c, a communication hole; I. an incident direction; l, L1, laser; n, normal direction; r, R1, irradiation area.