阅读说明：本技术 发光模块 (Light emitting module ) 是由 山崎力 于 2018-10-18 设计创作，主要内容包括：发光模块(1)具备基板(2)、面发光元件(3)以及光波导路(5)。阵列型的面发光元件(3)具有多个光源(3A),并且安装于基板(2)。光波导路(5)以覆盖多个光源(3A)的状态安装于面发光元件(3)。光波导路(5)在径向上具有折射率分布且沿轴向延伸。光波导路(5)使从面发光元件(3)射出的多个光线(R)会聚。(A light-emitting module (1) is provided with a substrate (2), a surface-emitting element (3), and an optical waveguide (5). The array-type surface-emitting element (3) has a plurality of light sources (3A) and is mounted on a substrate (2). The optical waveguide (5) is mounted on the surface light emitting element (3) in a state of covering the plurality of light sources (3A). The optical waveguide (5) has a refractive index distribution in the radial direction and extends in the axial direction. The optical waveguide (5) converges a plurality of light rays (R) emitted from the surface light-emitting element (3).)

1. A light-emitting module is characterized by comprising:

a substrate;

an array-type surface light emitting element provided on the substrate and having a plurality of light sources; and

an optical waveguide that is attached to the surface light emitting element so as to cover the plurality of light sources, has a refractive index distribution in a radial direction, and extends in an axial direction,

wherein the optical waveguide converges the plurality of light rays emitted from the surface light emitting element.

2. The lighting module of claim 1,

the optical waveguide has a lens at an exit end from which the light is emitted.

3. Light emitting module according to claim 1 or 2,

the optical waveguide is constituted by an optical fiber having a refractive index distribution core and formed of a resin material.

4. The lighting module according to any one of claims 1 to 3,

when a distance between an antinode portion where a plurality of light rays spread and a node portion where the plurality of light rays converge is Li and a protrusion dimension from the nearest antinode portion to the emission end of the optical waveguide is Lo, the protrusion dimension Lo is set to a value satisfying a relationship of Li/3< Lo < Li.

Technical Field

The present invention relates to a light emitting module that emits light.

Background

Patent document 1 describes a fiber lens including a multimode pigtail (Pigtail fiber) and a refractive lens. The fiber lens can condense light from a light source such as a laser diode at a focusing point by a refractive lens, for example, and can perform efficient optical coupling.

Disclosure of Invention

In the fiber lens described in patent document 1, a refractive lens is connected to a multimode pigtail. However, the refractive lens needs to be formed in a hyperbolic shape or an approximately hyperbolic shape, for example, so that the manufacturing cost is easily increased. In addition, the refractive lens and the multimode pigtail require a sufficiently high precision in positional alignment, and therefore there is a problem that it is difficult to connect them. In addition, in the fiber lens described in patent document 1, a multimode pigtail is used to input light to a refractive lens or a GRIN lens. Therefore, the overall shape tends to be larger than when light is directly incident on the lens.

The present invention has been made in view of the above-described problems of the prior art, and an object of the present invention is to provide a light emitting module that can be miniaturized and can output high-intensity light.

In order to solve the above problem, a light emitting module according to the present invention includes: a substrate; an array-type surface light emitting element provided on the substrate and having a plurality of light sources; and an optical waveguide that is attached to the surface light emitting element so as to cover the plurality of light sources, has a refractive index distribution in a radial direction, and extends in an axial direction, wherein the optical waveguide converges a plurality of light beams emitted from the surface light emitting element.

According to the present invention, it is possible to realize miniaturization and output high-intensity light.

Drawings

Fig. 1 is a sectional view showing a light emitting module of a first embodiment of the present invention.

Fig. 2 is a perspective view showing a surface light emitting element.

Fig. 3 is a sectional view showing a light emitting module of a second embodiment of the present invention.

Detailed Description

The light emitting module according to the embodiment of the present invention will be described in detail below with reference to the drawings.

Fig. 1 and 2 show a light-emitting module 1 according to a first embodiment of the present invention. The light emitting module 1 includes a substrate 2, a surface light emitting element 3, and an optical waveguide 5.

The substrate 2 is a flat plate formed using an insulating material. For example, a printed wiring board or a ceramic substrate is used as the substrate 2. The substrate 2 may be a multilayer substrate in which a plurality of electrode layers and insulating layers are alternately stacked. A surface light emitting element 3 is mounted on a surface 2A (one main surface) of the substrate 2. An electrode 4 is formed on the back surface 2B (the other main surface) of the substrate 2. The electrode 4 is electrically connected to the surface light emitting element 3. Therefore, a driving current is supplied to the surface light emitting element 3 from the outside through the electrode 4.

The surface light emitting element 3 is formed of, for example, an array type Vertical Cavity Surface Emitting Laser (VCSEL). The surface light emitting element 3 includes a plurality of (e.g., 9) light sources 3A (light emitting portions). The light sources 3A are located on the surface of the surface light emitting element 3, and are arranged in an array of 3 rows and 3 columns, for example. These light sources 3A emit light simultaneously. The light source 3A emits near infrared light in a 850nm band, for example. The light source 3A outputs light (light R) along the thickness direction of the surface light emitting element 3. The surface light emitting element 3 is mounted on the surface 2A of the substrate 2 by a bonding method such as a wire bonding technique. The number of the light sources 3A included in the surface light-emitting element 3 is not limited to 9, and may be 2 to 8, or may be 10 or more. The light source 3A may output light of other wavelengths.

The optical waveguide 5 is formed of a refractive index distribution type optical fiber. The optical waveguide 5 is constituted by an optical fiber having a refractive index distribution core 6 and formed of a resin material. The optical waveguide 5 may be formed using a material other than resin, such as a glass material.

The optical waveguide 5 includes a core 6 having a high refractive index and a cladding 7 having a low refractive index. The optical waveguide 5 is formed in a cylindrical shape. The core 6 is formed in a cylindrical shape and is positioned at the axial center of the optical waveguide 5. The cladding 7 is formed in a cylindrical shape, is located radially outward of the core 6, and covers the outer peripheral surface of the core 6.

The optical waveguide 5 has a refractive index distribution in the radial direction and extends in the axial direction along the central axis O. Specifically, the refractive index of the core 6 of the optical waveguide 5 is highest at the center position in the radial direction, and gradually (for example, in proportion to the square of the radius) becomes lower as going to the radially outer side. At this time, the light ray R incident on the position of the central axis O in the axial direction travels straight along the central axis O inside the optical waveguide 5. On the other hand, the light ray R incident in the axial direction at a position deviated from the central axis O propagates inside the optical waveguide 5 in a meandering manner so as to repeatedly approach and depart from the central axis O. Therefore, the optical waveguide 5 propagates the light incident from the incident end 5A to the emission end 5B while repeating the convergence and the diffusion.

The optical waveguide 5 has a length dimension of about 2mm to 4mm in the axial direction. At this time, a node portion a where the plurality of light rays R converge and an antinode portion B where the plurality of light rays R diffuse are formed in the optical waveguide 5. The node portions a and the antinode portions B are alternately arranged in the axial direction. The distance Li between the node portion a and the antinode portion B is determined by, for example, the refractive index distribution in the core 6, the wavelength of light propagating, and the like. The emission end 5B of the optical waveguide 5 is a flat surface orthogonal to the axial direction of the optical waveguide 5. The emission end 5B of the optical waveguide 5 is not limited to a flat surface, and may be a hemispherical surface that protrudes in a hemispherical shape toward the outside (emission direction), for example.

The emission end 5B of the optical waveguide 5 is disposed at a position protruding from the nearest antinode portion B by a predetermined protrusion dimension Lo. That is, the emission end 5B of the optical waveguide 5 is disposed at a position halfway from the antinode portion B to the node portion a. At this time, the projecting dimension Lo is set in a range greater than 1/3 of the spacing dimension Li and smaller than the spacing dimension Li (Li/3< Lo < Li). Thereby, the light propagating through the optical waveguide 5 is emitted from the emission end 5B in a state of being inclined to converge. Therefore, the light emitted from the emission end 5B is converged around the emission end 5B to form a spot S.

The optical waveguide 5 is attached to the surface light emitting element 3 using a bonding portion 8 formed of, for example, a transparent adhesive. The core 6 has a size covering all the light sources 3A of the area light emitting element 3. Therefore, light (light ray R) from all the light sources 3A of the surface light emitting element 3 is incident on the core 6. As long as the range is within which light (light rays R) from all the light sources 3A of the surface light-emitting element 3 can be incident, it is not necessary to strictly align the center of the core 6 with the center of the surface light-emitting element 3.

The light emitting module 1 according to the first embodiment of the present invention has the above-described configuration, and the operation thereof will be described below.

First, when a driving current is supplied to the surface light emitting element 3 through the electrode 4, the plurality of light sources 3A of the surface light emitting element 3 emit light. These light sources 3A output light rays R along the thickness direction of the substrate 2. At this time, the output surface (surface) of the surface light emitting element 3 is covered with the optical waveguide 5. Therefore, the light rays R from all the light sources 3A are incident on the core 6 of the optical waveguide 5. The light ray R incident on the incident end 5A of the optical waveguide 5 propagates in the axial direction of the optical waveguide 5 while repeating convergence and diffusion inside the optical waveguide 5. The light propagating through the optical waveguide 5 is emitted from the emission end 5B in a state of being inclined to converge. Thereby, the light output from the plurality of light sources 3A of the surface light emitting element 3 is converged around the emission end 5B of the optical waveguide 5 to form the point S.

In the light emitting module 1 of the present embodiment, the optical waveguide 5 converges the plurality of light rays R emitted from the surface light emitting element 3. Thus, the optical waveguide 5 converges the plurality of light rays R emitted from the plurality of light sources 3A of the surface light emitting element 3, and therefore, high-intensity light can be output from the optical waveguide 5. Further, since the surface emitting element 3 is mounted on the incident end 5A of the optical waveguide 5, it is not necessary to use a multimode pigtail as in the conventional technique, and the light emitting module 1 can be downsized.

The optical waveguide 5 is formed of an optical fiber having a refractive index distribution core 6 and made of a resin material. Therefore, the degree of freedom of the refractive index distribution can be increased, and therefore the optical waveguide 5 can be formed in accordance with the size of the surface light emitting element 3.

The emission end 5B of the optical waveguide 5 is disposed at a position protruding from the nearest antinode portion B by a predetermined protrusion dimension Lo. The protrusion dimension Lo is set in a range larger than 1/3 of the spacing dimension Li from the antinode portion B to the node portion a and smaller than the spacing dimension Li (Li/3< Lo < Li). Thereby, the light propagating through the optical waveguide 5 is emitted from the emission end 5B in a state of being inclined to converge. Therefore, the light emitted from the emission end 5B is converged around the emission end 5B to form a spot S.

Next, a second embodiment of the present invention will be described with reference to fig. 3. In a second embodiment, the optical waveguide includes a lens at a position of an emission end from which the light is emitted. In the second embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and descriptions thereof are omitted.

The light emitting module 11 of the second embodiment includes the substrate 2, the surface light emitting element 3, and the optical waveguide 12, as in the first embodiment. The optical waveguide 12 is formed in the same manner as the optical waveguide 5 of the first embodiment. Therefore, the optical waveguide 12 includes a core 13 and a cladding 14 similar to the core 6 and the cladding 7 of the first embodiment. The surface light emitting element 3 is mounted on the incident end 12A of the optical waveguide 12 via the joint 8.

The lens 15 is attached to the emission end 12B of the optical waveguide 12. In this case, the emission end 12B of the optical waveguide 12 need not be located at the halfway position from the antinode portion B to the node portion a of the optical waveguide 12, and may be located at the antinode portion B of the optical waveguide 12. The lens 15 is formed in a hemispherical shape protruding outward (in the emission direction), for example. At this time, the lens 15 is formed by using the surface tension of the resin material when the molten resin material adheres to the emission end 12B of the optical waveguide 12. After that, the resin material is cured to fix the lens 15 to the optical waveguide 12. The lens 15 is not limited to being formed by surface tension, and for example, a separately molded convex lens may be bonded to the emission end 12B of the optical waveguide 12, or a ball lens may be attached to the emission end 12B of the optical waveguide 12 by a jig or the like.

Accordingly, also in the second embodiment configured as described above, substantially the same operational effects as those in the first embodiment described above can be obtained. The optical waveguide 12 includes a lens 15 at a position of an emission end 12B from which the light ray R is emitted. Thus, the plurality of light rays R emitted from the plurality of light sources 3A of the surface light emitting element 3 can be converged by the lens 15. As a result, the light can be condensed to the diffraction limit.

The specific numerical values described in the above embodiments are examples, and are not limited to the illustrated values. These numerical values are set as appropriate, for example, according to the specification of the application object.

It is needless to say that the above embodiments are examples, and the structures described in the different embodiments may be partially replaced or combined.

Next, the invention included in the above-described embodiments will be described. The light emitting module of the present invention is characterized by comprising: a substrate; an array-type surface light emitting element provided on the substrate and having a plurality of light sources; and an optical waveguide that is attached to the surface light emitting element so as to cover the plurality of light sources, has a refractive index distribution in a radial direction, and extends in an axial direction, wherein the optical waveguide converges a plurality of light beams emitted from the surface light emitting element.

In this way, the optical waveguide can output high-intensity light from the optical waveguide because the optical waveguide converges a plurality of light beams emitted from a plurality of light sources of the surface light emitting element. Further, since the surface light emitting element is mounted on the incident end of the optical waveguide, it is not necessary to use a connector, and the light emitting module can be downsized.

In the present invention, the optical waveguide has a lens at a position of an exit end from which the light is emitted. In this way, the plurality of light beams emitted from the plurality of light sources of the surface light emitting element can be converged by the lens. As a result, the light can be condensed to the diffraction limit.

In the present invention, the optical waveguide is constituted by an optical fiber having a refractive index distribution core and formed of a resin material. This can increase the degree of freedom of the refractive index distribution, and thus an optical waveguide can be formed according to the size of the surface light emitting element.

In the present invention, when a distance between an antinode portion where a plurality of light rays spread and a node portion where the plurality of light rays converge is Li and a projection size from the nearest antinode portion to an emission end of the optical waveguide is Lo, the projection size Lo is set to a value satisfying a relationship of Li/3< Lo < Li. Thus, the light propagating through the optical waveguide is emitted from the emission end in a state of being inclined to converge. Therefore, the light emitted from the emission end is converged around the emission end and forms a spot.

Description of the reference numerals

1. 11: a light emitting module; 2: a substrate; 3: a surface light emitting element; 3A: a light source; 5. 12: an optical waveguide; 5A, 12A: an incident end; 5B, 12B: an exit end; 15: a lens.