Light-emitting device

Abstract

To provide a light-emitting device capable of keeping light emitted from a main lens within a target quality range.SOLUTION: A light source device includes a plurality of light-emitting elements containing a first light-emitting element and a second light-emitting element, and a case which seals the plurality of light-emitting elements, and has a translucent region through which light emitted from the plurality of light-emitting elements is transmitted, a plurality of main lenses which cover at least a part of the translucent region, and includes a first main lens for collimating or converging light emitted from the first light-emitting element, and a second main lens for collimating or converging light emitted from the second light-emitting element, and a plurality of sub-lenses which are arranged inside the case, and includes a first sub-lens located on an optical path between the first light-emitting element and the first main lens, and a second sub-lens located on an optical path between the second light-emitting element and the second main lens.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present disclosure relates to a light emitting device including a plurality of light emitting elements and a plurality of lenses. [Background technology]

[0002] Patent Document 1 discloses a light emitting device including a plurality of semiconductor laser elements and a lens array. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2007-019301 A Summary of the Invention [Problem to be solved by the invention]

[0004] Patent Document 1 discloses that when the positions of the light-emitting regions of two semiconductor laser elements have mounting errors, the parallelism of collimated light can be improved by adjusting the tilt angle of the lens array. However, it is difficult to sufficiently improve the adjustment accuracy by only adjusting the tilt angle of the lens array. There is a demand for a light-emitting device that can further improve the adjustment accuracy. [Means for solving the problem]

[0005] In one embodiment, the light emitting device of the present disclosure includes a plurality of light emitting elements including a first light emitting element and a second light emitting element; The present invention comprises: a case that seals the plurality of light-emitting elements, the case having a light-transmitting region that transmits light emitted from the plurality of light-emitting elements; a plurality of main lenses that cover at least a portion of the light-transmitting region, the plurality of main lenses including a first main lens that collimates or converges light emitted from the first light-emitting element and a second main lens that collimates or converges light emitted from the second light-emitting element; and a plurality of sub-lenses arranged inside the case, the plurality of sub-lenses including a first sub-lens located on an optical path between the first light-emitting element and the first main lens, and a second sub-lens located on an optical path between the second light-emitting element and the second main lens. Effect of the Invention

[0006] The above-described light emitting device makes it possible to keep the light emitted from the main lens within a target quality range. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is a diagram showing a schematic configuration example of a light emitting device having a plurality of light emitting elements and a plurality of collimating lenses but no secondary lens. [Diagram 2] FIG. 2 is a schematic diagram showing an example in which a light emitting device without a secondary lens includes a plurality of light emitting elements each emitting light with a different divergence angle. [Diagram 3] FIG. 3 is a diagram showing an example of a basic configuration of a light emitting device according to the present disclosure. [Figure 4A] FIG. 4A is a perspective view showing a light emitting device according to the first embodiment of the present disclosure. [Figure 4B] FIG. 4B is a perspective view showing the inside of the light emitting device according to the first embodiment. [Diagram 5] FIG. 5 is a diagram showing (a) the top surface as viewed from the positive direction of the Z axis, (b) a side surface as viewed from the positive direction of the X axis, and (c) a side surface as viewed from the positive direction of the Y axis of the light emitting device in the first embodiment. [Figure 6] FIG. 6 is a cross-sectional view showing the light emitting device according to the first embodiment. [Figure 7]FIG. 7 is a plan view showing the internal configuration of the light emitting device according to the first embodiment. [Figure 8] FIG. 8 is a perspective view showing an example of a lens array that can be used in the light emitting device according to the first embodiment. [Figure 9A] FIG. 9A is a perspective view showing a light emitting device according to the second embodiment of the present disclosure. [Figure 9B] FIG. 9B is a perspective view showing the inside of the light emitting device according to the second embodiment. [Figure 10] FIG. 10 is a diagram showing (a) the top surface as viewed from the positive direction of the Z axis, (b) a side surface as viewed from the positive direction of the X axis, and (c) a side surface as viewed from the positive direction of the Y axis of a light emitting device in the second embodiment. [Figure 11] FIG. 11 is a cross-sectional view showing a light emitting device according to the second embodiment. [Figure 12] FIG. 12 is a plan view showing the internal configuration of the light emitting device according to the second embodiment. [Figure 13A] FIG. 13A is a perspective view showing a light emitting device according to a third embodiment of the present disclosure. [Figure 13B] FIG. 13B is a perspective view showing the inside of the light emitting device according to the third embodiment. [Figure 14] FIG. 14 is a diagram showing (a) the top surface as viewed from the positive direction of the Z axis, (b) a side surface as viewed from the positive direction of the X axis, and (c) a side surface as viewed from the positive direction of the Y axis of a light emitting device in the third embodiment. [Figure 15] FIG. 15 is a cross-sectional view showing a light emitting device according to the third embodiment. [Figure 16] FIG. 16 is a plan view showing the internal configuration of the light emitting device according to the third embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Before describing the embodiments of the present disclosure, the findings of the present inventors and the technical background thereof will be described.

[0009] First, with reference to FIG. 1 and FIG. 2, some problems that may occur in a light emitting device in which light emitted from a plurality of light emitting elements is collimated or focused by a plurality of lenses will be described.

[0010] FIG. 1 is a diagram showing a schematic configuration example of a light emitting device 100P including a plurality of laser diodes 110 and a plurality of lenses 140. The light emitting device 100P does not include a secondary lens, that is, the lens that the light L emitted from the laser diode 110 first reaches is the lens 140. The lens 140 in this example is an optical element that collimates the light L emitted from the laser diode 110. In this case, the light emitting device 100P is designed with the intention that the light emitted from each lens 140 is collimated into a substantially parallel beam. Therefore, the design position and orientation of each laser diode 110 are determined so that the "light emitting region" on the output end surface of the laser diode 110 coincides with or near the focus of the lens 140, and the center of the light L is perpendicularly incident on the light incident surface of the lens 140. The light emitting region of the laser diode is also called an emitter region. Hereinafter, the design position of the light emitting region may be called a "target position". The target position of the light-emitting region of the laser diode 110 does not necessarily have to completely coincide with the focal point of the lens 140, and can be determined so as to form a desired light beam. For example, in order to control the beam shape of the collimated light L, a position slightly away from the focal point may be intentionally set as the target position, and the light-emitting region may be disposed at the target position. Even in such a case, it is required to accurately dispose the light-emitting region of the laser diode 110 at the design position, i.e., the target position, determined based on the optical design.

[0011] When the laser diodes 110 are mounted, the positions of the laser diodes 110 may deviate from the target positions. Such deviations may occur due to variations in mounting the laser diodes 110. If the laser diodes 110 deviate from the designed positions, such as when the light-emitting regions deviate from the target positions, the direction and / or spread angle of the light transmitted through the lens 140 may deviate from the designed range. In the example of FIG. 1, the light-emitting regions of the laser diodes 110 deviate from the target positions, so that the light beams transmitted through the lens 140 are not collimated as designed, and the direction and spread angle of the light beams deviate from the targets.

[0012] The positional deviation of the laser diode 110 may occur separately for each laser diode 110. If the position or orientation of each lens 140 can be adjusted to match the position of the light-emitting region after mounting the laser diode 110, a desired collimated light may be obtained. However, if each lens 140 is fixed to a common member or integrally formed from the same material, such individual adjustment cannot be performed. Also, if the lens 140 is fixed on a light-transmitting member of a package, the movable range of the adjustable lens 140 becomes narrow, so that the positional deviation of the light-emitting region may not be corrected by only adjusting the position of each lens 140.

[0013] FIG. 2 is a diagram showing an example in which a plurality of laser diodes 110 included in the light emitting device 100P each emit light L with a different divergence angle. As in FIG. 1, the light emitting device 100P in FIG. 2 does not include a secondary lens. The divergence angle of the light L emitted by the laser diode 110 is not uniform, for example, when the laser diode 110 emits light of different colors. In this case, the structure and size of the laser diode 110 may differ from each other, so the divergence angle of the emitted light may differ. In such a case, the beam diameter of the light beam transmitted through the lens 140 may become non-uniform. If the focal length of the lens 140 is changed according to the type of the laser diode 110 to make the beam diameter of the collimated light closer to uniform, it is necessary to increase the size of the light emitting device 100P in the optical axis direction.

[0014] Such a problem is not limited to the laser diode 110, but can occur when combining various light emitting elements and lenses.

[0015] <Basic configuration> Hereinafter, an embodiment of the present disclosure will be described. First, with reference to FIG. 3, an example of a basic configuration of a light-emitting device common to the embodiments described below will be described. FIG. 3 is a diagram showing a schematic configuration example of a light-emitting device. For reference, these drawings show an X-axis, a Y-axis, and a Z-axis that are perpendicular to each other. The orientation of the light-emitting device during use is arbitrary and is not limited by the orientation of the light-emitting device shown in the drawings.

[0016] The light emitting device 100 includes a plurality of light emitting elements 10 including a first light emitting element 10A and a second light emitting element 10B, and a case 20 sealing the plurality of light emitting elements 10. The light emitting elements 10 may be hermetically sealed by the case 20. As shown in the example described later, the number of the light emitting elements 10 is not limited to two, and may be three or more. An example of the light emitting element 10 may be a laser element such as an edge-emitting semiconductor laser element or a vertical cavity surface emitting laser element (VCSEL). As such a laser element, a laser diode (LD) having a semiconductor layer may be used. The light emitting element 10 may be a light emitting element such as a light emitting diode (LED) that emits non-coherent light. The light emitting element 10 is preferably a laser element. This is because the laser light emitted by the laser element has a higher linearity than the light emitted by the LED, and a larger proportion of the light can be irradiated onto the lens. The light emitting region of the light emitting element 10 is a region of the surface of the light emitting element 10 from which the light L is emitted. When the light emitting element 10 is a laser element, the light emitting region of the light emitting element 10 refers to a region from which a laser beam is emitted. The light emitted from the light-emitting element 10 is, for example, visible light. The wavelength of the light is not limited to the visible light range, and may be in the infrared or ultraviolet range. Furthermore, the multiple light-emitting elements 10 may each emit light in a different wavelength range, or may emit light of a different color. In the example of FIG. 3, the peak wavelength of the light emitted from the first light-emitting element 10A is different from the peak wavelength of the light emitted from the second light-emitting element 10B.

[0017] The case 20 has a light-transmitting region 30 that transmits the light L emitted from the multiple light-emitting elements 10. The light-transmitting region 30 is, for example, glass. The case 20 may also be called a package. A specific configuration example of the case 20 will be described later.

[0018] The light emitting device 100 includes a plurality of main lenses 40 covering at least a portion of the light transmitting region 30. The plurality of main lenses 40 include a first main lens 40A that collimates or converges the light L emitted from the first light emitting element 10A, and a second main lens 40B that collimates or converges the light L emitted from the second light emitting element 10B. In the illustrated example, the main lens 40 is a collimating lens.

[0019] Furthermore, the light emitting device 100 includes a plurality of sub lenses 50 disposed inside the case 20. The plurality of sub lenses 50 include a first sub lens 50A located on the optical path between the first light emitting element 10A and the first main lens 40A, and a second sub lens 50B located on the optical path between the second light emitting element 10B and the second main lens 40B. For this reason, the light emitted from the first light emitting element 10A is incident on the first main lens 40A after passing through the first sub lens 50A. The first sub lens 50A performs an auxiliary function of the first main lens 40A, and the combination of the first main lens 40A and the first sub lens 50A can realize the desired collimation or convergence. Similarly, the light emitted from the second light emitting element 10B is incident on the second main lens 40B after passing through the second sub lens 50B. The second secondary lens 50B performs a supplementary function to the second primary lens 40B, and the combination of the second primary lens 40B and the second secondary lens 50B may achieve a desired collimation or convergence. Therefore, the lens shape of the primary lens 40 may be different from the lens shape when the secondary lens 50 is not used.

[0020] In Fig. 3, the light L is represented diagrammatically by the region enclosed by two dashed lines. The intensity of the light L, such as a laser beam, can be approximately represented by, for example, a Gaussian distribution in a plane perpendicular to the propagation direction of the center of the light L. The diameter of such a beam of light L is, for example, 1 / e 2 The beam diameter may be defined by the size of the region having a light intensity equal to or greater than e, where e is Napier's constant (approximately 2.71). The beam diameter may also be defined by other criteria.

[0021] Each of the multiple secondary lenses 50 may be mounted in the case 20 independently of each other. Therefore, the position and orientation of each secondary lens 50 may be adjusted without being restricted by each other. Note that in FIG. 3, for simplicity, the illustration of the member supporting the secondary lens 50 is omitted. Each secondary lens 50 may be fixed to the case 20 directly or indirectly.

[0022] The position and orientation of the first sub-lens 50A are determined according to the position and orientation of the first light-emitting element 10A after the first light-emitting element 10A is mounted in the case 20. Similarly, the position and orientation of the second sub-lens 50B are determined according to the position and orientation of the second light-emitting element 10B after the second light-emitting element 10B is mounted in the case 20. Each of the multiple sub-lenses 50 can perform a function of compensating for a position and / or orientation shift of the multiple light-emitting elements 10. In addition, even if there is no mounting shift in the multiple light-emitting elements 10, each of the multiple sub-lenses 50 can also perform a function of adjusting the beam diameter or beam convergence point position that may differ based on differences in characteristics such as the wavelength and spread angle of the light emitted from the multiple light-emitting elements 10. From these functions, the sub-lens 50 may be called a correction lens or an adjustment lens.

[0023] The adjustment of the position and orientation of each secondary lens 50 may be performed while measuring the light L transmitted through the secondary lens 50 with a device such as a beam profiler while emitting light L from the light emitting element 10. For example, when the secondary lens 50 is fixed to the case 20 with ultraviolet curing resin, the above adjustment is performed with the uncured ultraviolet curing resin interposed between the secondary lens 50 and the case 20. Then, after determining the position and orientation of the secondary lens 50, ultraviolet light may be irradiated onto the resin while the position and orientation of the secondary lens 50 is held by a jig or holding device to harden the resin. Instead of using resin, a bonding material containing a metal that softens or melts when heated may be used. Adjusting the direction and / or spread angle of the light L emitted from the light emitting device 100 by mounting the secondary lens 50 with the light L emitted from the light emitting element 10 in this manner may be called "active alignment". After such active alignment is completed, the primary lens 40 is mounted.

[0024] Light L corrected by the secondary lens 50 is incident on the primary lens 40. This makes it possible to keep the light emitted from the primary lens 40 within a target quality range. This quality includes the light propagation direction, spread angle, and size. "Keeping within a target quality range" means that one or more of these fall within the target range, and it is preferable that all of them fall within the target range.

[0025] Furthermore, even if a lens array is used in which a plurality of main lenses 40 are linked together, it is possible to obtain a plurality of light beams each having a target quality by adjusting the position to the extent possible for a lens array.

[0026] In FIG. 3, the main lens 40 is fixed directly or indirectly to the case 20 outside the case 20. If the main lens 40 is arranged inside the case 20, the light collimated or converged by the main lens 40 passes through the light-transmitting region 30 and is taken out to the outside of the case 20. In that case, the possibility of the light being refracted in the light-transmitting region 30 and deteriorating the beam quality cannot be excluded. For this reason, as shown in FIG. 3, it is preferable to attach the main lens 40 to the outside of the case 20. This makes it possible to avoid such deterioration of the beam quality. On the other hand, the secondary lens 50 is arranged inside the case 20, not outside. The light L emitted by the light-emitting element 10 diffuses over a wide range as it moves away from the light-emitting region. By arranging the secondary lens 50 inside the case 20, the secondary lens 50 can be brought closer to the light-emitting region of the light-emitting element 10, so that a correction effect can be obtained by the secondary lens 50 of a smaller size than when it is arranged outside the case 20. This is therefore advantageous for miniaturizing the light-emitting device 100.

[0027] <First embodiment> The first embodiment will be described below with reference to FIGS. 4A to 8. FIG.

[0028] First, a schematic configuration of the light emitting device 100 in the first embodiment will be described with reference to Fig. 4A, Fig. 4B, Fig. 5(a), Fig. 5(b), and Fig. 5(c). Fig. 4A is a perspective view showing the exterior of the light emitting device 100 in the first embodiment. Fig. 4B is a perspective view showing the inside of the light emitting device 100 in the first embodiment. Fig. 5(a), Fig. 5(b), and Fig. 5(c) are diagrams showing the top view of the light emitting device 100 in the first embodiment as viewed from the positive direction of the Z axis, the side view as viewed from the positive direction of the X axis, and the side view as viewed from the positive direction of the Y axis, respectively.

[0029] The light emitting device 100 in the first embodiment includes a plurality of light emitting elements 10 including a first light emitting element 10A, a second light emitting element 10B, and a third light emitting element 10C, and a case 20 that seals the plurality of light emitting elements 10.

[0030] In the arrangement example of FIG. 4B, light is emitted from each of the light-emitting elements 10A, 10B, and 10C in the negative direction of the Y axis. Three reflectors R that reflect the light emitted from the three light-emitting elements 10 in the positive direction of the Z axis are arranged inside the case 20. Also, as shown in FIG. 4A, the case 20 has a cover 32 including a light-transmitting region that transmits the light reflected by the reflector R. In this example, the entire cover 32 is made of a light-transmitting material and functions as a light-transmitting region. A part of the cover 32, rather than the entire cover 32, may function as a light-transmitting region. The light-emitting device 100 includes a plurality of main lenses 40 that cover at least a part of the cover 32, i.e., a first main lens 40A, a second main lens 40B, and a third main lens 40C, and a plurality of sub-lenses 50 that are arranged inside the case 20, i.e., a first sub-lens 50A, a second sub-lens 50B, and a third sub-lens 50C. In this example, multiple secondary lenses 50 are disposed between the multiple light emitting elements 10 and the reflector R, respectively.

[0031] Next, the configuration of the light emitting device 100 in the first embodiment will be described in detail with reference to Fig. 6, Fig. 7, and Fig. 8. Fig. 6 is a cross-sectional view showing the light emitting device 100 in the first embodiment. Fig. 7 is a plan view showing the internal configuration of the light emitting device 100, with the illustration of the cover 32 and the main lens 40 omitted. Fig. 8 is a perspective view showing an example of the configuration of a lens array 400 that the light emitting device 100 can be equipped with.

[0032] As shown in FIG. 6, the case 20 of the light emitting device 100 has a base 22 that supports the light emitting elements 10, and a cover 32 that covers the light emitting elements 10. The cover 32 may be made of a light-transmitting material such as sapphire. The cover 32 has, for example, a plate made of a light-transmitting material. A metal layer may be provided on the surface of the plate. The base 22 includes a bottom 24 on which the multiple light emitting elements 10 are arranged, and a frame 26 that surrounds the multiple light emitting elements 10. The cover 32 on which the main lens 40 is placed is supported by the frame 26.

[0033] The base 22 has an electrode structure for electrically connecting the light-emitting element 10 to an external power source, and the light-emitting element 10 is electrically connected to this electrode structure. Therefore, the base 22 also plays a role in electrically connecting the light-emitting element 10 to an external power source. The base 22 may be formed from a composite of an insulating material and a conductive material. The base 22 has, for example, an insulating ceramic body and a conductive metal portion that functions as an electrode.

[0034] In the example shown in FIG. 6, the frame 26 has a step between the cover 32 and the bottom 24. At least a part of the electrode structure for connecting the light emitting element 10 to an external power source may be formed on the surface 28 of the step. A part of the electrode structure may be a via electrode penetrating the base 22. The electrode structure and the light emitting element 10 may be electrically connected by, for example, a wire. In FIG. 6, the wire is omitted. In FIG. 7, six wires 60 are diagrammatically illustrated. These wires 60 electrically connect the conductive layer, which is a part of the electrode structure formed on the surface 28 of the step, to each light emitting element 10. In FIG. 7, the wires 60 are illustrated as straight lines, but the wires 60 may be curved or bent.

[0035] In the example of FIG. 6, each light-emitting element 10 is fixed to a submount 12, and the submount 12 is fixed to the base 22. The submount 12 can be omitted from the configuration of the light-emitting device 100. The submount 12 can be formed of a material having a higher thermal conductivity than that of the base 22 in order to enhance heat dissipation. The light-emitting region of the light-emitting element 10 is on the reflector R side, and light L is emitted from the light-emitting region toward the reflector R. In FIG. 6, the optical axis (center) of the light L is diagrammatically shown by a straight arrow. A secondary lens 50 is disposed between the light-emitting region of the light-emitting element 10 and the reflector R. As described above, the position of the secondary lens 50 is adjusted to compensate for the deviation of the light-emitting element 10 from the target position, and then fixed to the base 22. This "compensation" does not necessarily mean that the focal point of the lens system consisting of the combination of the primary lens 40 and the secondary lens 50 and the light-emitting region of the light-emitting element 10 are strictly aligned. "Compensation" includes adjusting the position and / or orientation of the secondary lens 50 so that the position of this focal point is relatively closer to the light-emitting area of ​​the light-emitting element 10 than would be the case if the secondary lens 50 were not present.

[0036] The position and orientation of each of the secondary lenses 50 are preferably such that the focal point defined by the pair of the primary lens 40 and the secondary lens 50 coincides with the light-emitting area of ​​the light-emitting element 10. This allows the light L transmitted through each of the secondary lenses 50 to be collimated or converged by the corresponding primary lens 40 more reliably. In addition, it is preferable that at least one of the primary lens 40 and the secondary lens 50 is not a lens array in which multiple lenses are connected, but is an individual lens component in which multiple lenses are each independent. This allows the range in which the focal point defined by the pair of the primary lens 40 and the secondary lens 50 can be adjusted to be expanded compared to when both are lens arrays. This makes it easier to match the focal point with the light-emitting area of ​​the light-emitting element 10.

[0037] The reflector R has a light reflecting surface on at least one side. The light reflecting surface is inclined with respect to the bottom surface of the reflector R, and reflects the light L from the light emitting element 10 toward the transmission area. The reflector R is preferably formed from a material that is resistant to heat in order to receive the light emitted from the light emitting element 10. The light reflecting surface may be formed from a layer of a material with high reflectivity. The main body portion of the reflector R may be formed from glass such as quartz or BK7 (borosilicate glass), a metal such as aluminum, or Si. The light reflecting surface may be formed from a metal layer and / or a dielectric multilayer film.

[0038] The secondary lens 50 preferably has a shape that allows bonding to the base 22, for example, a rectangular parallelepiped shape. The secondary lens 50 has a curved surface as a part of the lens shape. This curved surface may be convex or concave. The secondary lens 50 may be formed from glass such as BK7 or B270. The primary lens 40 may also be formed from glass such as BK7 or B270. As shown in FIG. 4A, the primary lens 40 includes three primary lenses 40A, 40B, and 40C arranged in the X-axis direction. As long as the shape of each of the primary lenses 40A, 40B, and 40C has a lens-shaped portion having a spherical or aspherical surface in the portion through which the light L passes, the shape of the other portion is arbitrary. In FIG. 4A, the lens-shaped portion of the primary lens 40 is a convex portion protruding upward from the plate-shaped portion. Densely arranging the multiple convex portions of the primary lens 40 is beneficial for miniaturizing the light-emitting device 100. The distance between each of the multiple convex portions of the main lens 40 can be made smaller than the width of one convex portion in the X-axis direction, for example.

[0039] The main lenses 40A, 40B, and 40C may be bonded to the cover 32 as individual lens components, or may be fixed to the cover 32 as a single integrated lens array. FIG. 8 is a perspective view showing a configuration example of a lens array 400 in which the main lenses 40A, 40B, and 40C are connected. The lens array 400 is a one-piece body having a structure in which the main lenses 40A, 40B, and 40C are closely arranged in the X-axis direction. There may be gaps between the first main lens 40A and the second main lens 40B, and between the second main lens 40B and the third main lens 40C, or the three main lenses 40A, 40B, and 40C may be connected without gaps.

[0040] As shown in FIG. 6, the main lens 40 may be fixed to the cover 32 via a bonding layer 34. The bonding layer 34 may be made of, for example, an ultraviolet curing resin. The lens array 400 shown in FIG. 8 may also be fixed to the cover 32 via a similar bonding layer. In the lens array 400, the relative positions of the main lenses 40A, 40B, and 40C are fixed, so there is no need to separately fix each of the main lenses 40A, 40B, and 40C to the cover 32. The lens array 400 has the advantage of being easy to mount, since it is handled as an integrated component.

[0041] The light emitted by the multiple light emitting elements 10 may be different colors. For example, blue, green, and red light may be used. In the first embodiment, the first light emitting element 10A, the second light emitting element 10B, and the third light emitting element 10C are a green semiconductor laser element that emits a green laser beam, a blue semiconductor laser element that emits a blue laser beam, and a red semiconductor laser element that emits a red laser beam, respectively. All of them are end-emission types.

[0042] The blue semiconductor laser element emits a laser beam having a peak wavelength of 430 nm to 480 nm, and may be 450 nm to 470 nm. The green semiconductor laser element emits a laser beam having a peak wavelength of 500 nm to 550 nm, and may be 520 nm to 540 nm. The red semiconductor laser element emits a laser beam having a peak wavelength of 620 nm to 660 nm, and may be 630 nm to 650 nm. The blue semiconductor laser element and the green semiconductor laser element may be mainly made of a nitride semiconductor. Examples of nitride semiconductors include GaN, InGaN, and AlGaN. The red semiconductor laser element may be mainly made of a gallium arsenide-based semiconductor. When a laser element is used as the light-emitting element 10, the stronger the light energy, the more easily dust particles in the atmosphere will adhere to the light-emitting surface of the laser element during operation due to the light-collecting effect. If dust particles adhere to the light-emitting surface, the light output may decrease. The shorter the wavelength of the laser beam is, and the higher the light output is, the higher the light energy is. For this reason, when a laser element that emits a laser beam of green or a shorter wavelength is adopted as the light emitting element 10, it is preferable that the light emitting element 10 is hermetically sealed by the case 20. If the light emitting element 10 is packaged in a hermetically sealed manner by the case 20, it is possible to prevent external dust from entering the case 20, thereby reducing the possibility of dust or the like adhering to the light emitting surface of the laser element.

[0043] The characteristics of the red semiconductor laser element may be more susceptible to temperature fluctuations than those of the blue and green semiconductor laser elements. In addition, the blue semiconductor laser element has a better power conversion efficiency than the green semiconductor laser element, and therefore generates less heat than the green semiconductor laser element. For this reason, it is desirable to place the green semiconductor laser element away from the red semiconductor laser element. In this embodiment, as shown in FIG. 7, the blue semiconductor laser element (second light-emitting element 10B) is placed between the red semiconductor laser element (third light-emitting element 10C) and the green semiconductor laser element (first light-emitting element 10A). As a result, the light-emitting characteristics of the red semiconductor laser element (third light-emitting element 10C) are stabilized.

[0044] A semiconductor element other than the light-emitting element 10 may be disposed inside the case 20. For example, a protection circuit element such as a Zener diode that suppresses the reverse voltage applied to each light-emitting element 10 to a predetermined level or less, and / or a light detection element such as a photodiode that monitors the intensity of the light L may be disposed.

[0045] In the first embodiment, the secondary lens 50 can be disposed in a position close to the light-emitting region of the light-emitting element 10, so that the light L emitted from the light-emitting region is incident on the secondary lens 50 before it spreads widely. This allows the size of the secondary lens 50 to be reduced. In addition, by adjusting the position of the secondary lens 50 within the case 20, the positional deviation of the light-emitting region can be corrected. The shape and size of the secondary lens 50 are not limited to the example shown in the figure. In addition, in the case where the beam size of the light L from the multiple light-emitting elements 10 on the light incidence surface of the main lens 40 becomes uneven without the secondary lens 50, the secondary lens 50 can be used to adjust the beam size of each light L to make it closer to uniform.

[0046] <Second embodiment> The second embodiment will now be described with reference to FIGS. 9A to 12. FIG.

[0047] First, a schematic configuration of a light emitting device 100 in the second embodiment will be described with reference to Fig. 9A, Fig. 9B, Fig. 10(a), Fig. 10(b), and Fig. 10(c). Fig. 9A is a perspective view showing the light emitting device in the second embodiment. Fig. 9B is a perspective view showing the inside of the light emitting device in the second embodiment. Fig. 10(a), Fig. 10(b), and Fig. 10(c) are views showing the top view of the light emitting device in Fig. 9A as viewed from the positive direction of the Z axis, the side view as viewed from the positive direction of the X axis, and the side view as viewed from the positive direction of the Y axis, respectively.

[0048] The light emitting device 100 in the second embodiment includes a plurality of light emitting elements 10 including a first light emitting element 10A, a second light emitting element 10B, and a third light emitting element 10C, and a case 20 that seals the plurality of light emitting elements 10, similar to the light emitting device 100 in the first embodiment described above. The difference from the first embodiment is in the configuration of a plurality of secondary lenses 50 arranged inside the case 20. This point will be described in detail below.

[0049] 9B, the light emitting device 100 of the second embodiment includes a first sub-lens 50A, a second sub-lens 50B, and a third sub-lens 50C. In the second embodiment, the multiple sub-lenses 50 are each disposed between the cover 32 and the reflector R.

[0050] Next, the configuration of the secondary lens 50 in the light emitting device 100 in the second embodiment will be described with reference to Figures 11 and 12. Figure 11 is a cross-sectional view showing the light emitting device 100 in the second embodiment. Figure 12 is a plan view showing the internal configuration of the light emitting device 100 in the second embodiment, with the illustration of the cover 32 and the main lens 40 omitted.

[0051] 11, also in the second embodiment, the case 20 of the light emitting device 100 has a base 22 that supports the multiple light emitting elements 10, a reflector R supported by the base 22, and a cover 32 that covers the multiple light emitting elements 10. The base 22 includes a bottom 24 on which the multiple light emitting elements 10 and the reflector R are arranged, and a frame 26 that surrounds the multiple light emitting elements 10. The cover 32 on which the main lens 40 is placed is supported by the frame 26. As the main lens 40, the lens array 400 of FIG. 8 may be adopted.

[0052] 11, the frame 26 has two steps between the cover 32 and the bottom 24. At least a part of the electrode structure for connecting the light-emitting element 10 to an external power supply may be formed on surface 28A, which is one of the surfaces constituting the lower step. In the second embodiment, each of the multiple secondary lenses 50 is supported by surface 28B, which is one of the surfaces constituting the upper step of the frame 26.

[0053] The wires are omitted in Figures 11 and 12. The light emitting device 100 in the second embodiment also includes the electrode structure and wires described in the first embodiment, and the description thereof will not be repeated here.

[0054] As shown in FIG. 12, each of the secondary lenses 50A, 50B, and 50C has a flat extension 52 that expands like a plate and a convex portion having a curved surface as a lens-shaped portion. The convex portion functions as a lens. Each of the secondary lenses 50A, 50B, and 50C is an individual component, and is formed from, for example, a glass material. Each of the secondary lenses 50A, 50B, and 50C has a substantially rectangular shape in a plan view, and its size in the Y-axis direction has a length that spans from the left part to the right part of the surface 28B of the frame portion 26. Before being fixed to the frame portion 26, each of the secondary lenses 50A, 50B, and 50C can slide in the X-axis direction with both ends supported by the surface 28B of the frame portion 26. In this state, each of the secondary lenses 50A, 50B, and 50C can also slide in the Y-axis direction. In order to enable such sliding in the Y-axis direction, the distance L1 in the Y-axis direction of the side extending in the positive direction of the Z-axis from the outer end of the surface 28B is longer than the length L2 of each of the secondary lenses 50A, 50B, and 50C. The distance L1 may be rephrased as the distance from the left end of the left part of the surface 28B to the right end of the right part of the surface 28B. The difference in length, L1-L2, defines the upper limit of the movable amount in the Y-axis direction of the secondary lenses 50A, 50B, and 50C. L1-L2 may be set in an appropriate range depending on the size of the light-emitting device 100. L2 may be set, for example, to be 0.5 times or more and 0.95 times or less of L1. L1-L2 may be set, for example, to be about 0.02 mm to 3 mm. Since the surface 28B supports both ends of the secondary lenses 50A, 50B, and 50C, the distance L3 in the Y-axis direction of the side extending in the negative direction of the Z-axis from the inner end of the surface 28B is shorter than the length L2 of each of the secondary lenses 50A, 50B, and 50C. The distance L3 may be rephrased as the distance from the right end of the left part of the surface 28B to the left end of the right part of the surface 28B. L3 may be set to, for example, 0.5 to 0.95 times L2. The difference between these lengths, L2-L3, may be set to, for example, about 0.02 mm to 3 mm.

[0055] In the second embodiment, when the secondary lenses 50A, 50B, and 50C are fixed to the frame portion 26, they can be slid two-dimensionally along the surface 28B of the step portion, making it easy to adjust the positions of the secondary lenses 50A, 50B, and 50C.

[0056] When adjusting the positions of the secondary lenses 50A, 50B, and 50C in the Z-axis direction, the thickness of the bonding layer provided between the surface 28B of the step portion and the lower surfaces of the secondary lenses 50A, 50B, and 50C may be adjusted.

[0057] As described for the first embodiment, when the secondary lenses 50A, 50B, 50C are fixed to the case 20 with ultraviolet curing resin, adjustment is performed with uncured ultraviolet curing resin interposed between the undersides of the secondary lenses 50A, 50B, 50C and the surface 28B of the step portion. Then, after determining the positions and orientations of the secondary lenses 50A, 50B, 50C, the resin is cured by irradiating it with ultraviolet light while holding the position and orientation of each secondary lens 50 with a jig or holding device.

[0058] In the light emitting device 100 of the second embodiment, each of the multiple secondary lenses 50 is supported by a step portion of the frame portion 26. This allows the secondary lenses 50 to be disposed above the light emitting element 10 and the reflector R, which has the advantage of making it easier to handle the individual secondary lenses 50A, 50B, and 50C and facilitating positioning in the XY plane. On the other hand, the movable distance when adjusting the position of the secondary lens 50 along the light propagation direction, i.e., the optical axis direction, can be made larger in the first embodiment than in the second embodiment. In addition, the first embodiment is more advantageous in terms of miniaturization. This is because in the second embodiment, the distance from the light emitting region of the light emitting element 10 to the corresponding secondary lens 50 is relatively long, and the size of the convex portion having the lens function of the secondary lens 50 is relatively large.

[0059] In each of the above-described embodiments, the light emitting device 100 includes the reflector R, but the reflector R is not an essential element.

[0060] <Embodiment 3> The third embodiment will be described below with reference to Figures 13A to 16. The light emitting device 100 in the third embodiment does not include a reflector R.

[0061] First, a schematic configuration of a light emitting device 100 in the third embodiment will be described with reference to Fig. 13A, Fig. 13B, Fig. 14(a), Fig. 14(b), and Fig. 14(c). Fig. 13A is a perspective view showing the light emitting device in the third embodiment. Fig. 13B is a perspective view showing the inside of the light emitting device in the third embodiment. Fig. 14(a), Fig. 14(b), and Fig. 14(c) are diagrams showing the top view of the light emitting device in the third embodiment as viewed from the positive direction of the Z axis, the side view as viewed from the positive direction of the X axis, and the side view as viewed from the positive direction of the Y axis, respectively.

[0062] The light emitting device 100 in the third embodiment also includes a plurality of light emitting elements 10 including a first light emitting element 10A, a second light emitting element 10B, and a third light emitting element 10C, and a case 20 that seals the plurality of light emitting elements 10, as in the first and second embodiments. However, the light emitting device 100 in the third embodiment does not include a reflector R. Light emitted from the plurality of light emitting elements 10 arranged inside the case 20 is extracted from the side of the case 20. This point will be described in detail below. The case 20 has a lid portion 70 that covers the frame portion 26. In FIG. 13B, the lid portion 70 and the main lens 40 are omitted.

[0063] As shown in FIG. 13A, the light emitting device 100 of this embodiment includes a first main lens 40A, a second main lens 40B, and a third main lens 40C fixed to a cover 32 located on a side surface of the case 20. The light emitting device 100 also includes a first sub lens 50A, a second sub lens 50B, and a third sub lens 50C inside the case 20. In the third embodiment, the first sub lens 50A is located on the optical path between the first light emitting element 10A and the first main lens 40A. The second sub lens 50B is located on the optical path between the second light emitting element 10B and the second main lens 40B. The third sub lens 50C is located on the optical path between the third light emitting element 10C and the third main lens 40C.

[0064] Next, the configuration of the light emitting device 100 in the third embodiment will be further described with reference to Fig. 15 and Fig. 16. Fig. 15 is a cross-sectional view showing the light emitting device 100 in the third embodiment. Fig. 16 is a plan view showing the internal configuration of the light emitting device 100, with the lid portion 70 omitted.

[0065] 15, in the third embodiment, an opening 26X is formed on a side surface of the case 20, specifically, in a part of the frame portion 26. The opening 26X of the frame portion 26 is closed by a cover 32. The main lens 40 is fixed to the frame portion 26 by a bonding layer 34. The main lens 40 may be fixed to the cover 32.

[0066] Light L is emitted in the positive direction of the Y axis from each of the light emitting elements 10A, 10B, and 10C. Three secondary lenses 50 are arranged inside the case 20 so as to transmit the light emitted from the three light emitting elements 10.

[0067] The lid portion 70 does not need to have a light-transmitting material, but the cover 32 does. At least the portion of the cover 32 that transmits the light L is made of a light-transmitting material. The light L transmitted through each of the three secondary lenses 50 is collimated or focused by the corresponding primary lens 40. The adjustment and fixation of each secondary lens 50 can be performed by the method described for the first embodiment. The light-emitting device 100 in the third embodiment also includes the electrode structure and wires 60 described above.

[0068] According to the third embodiment, the light emitting device 100 does not require a reflector, so the number of components is reduced, and the size of the light emitting device 100 can be reduced.

[0069] The above-described embodiments are merely examples of light-emitting devices for embodying the technical ideas of the present invention, and the present invention is not limited thereto. In addition, the present disclosure does not specify the members shown in the claims to the members of each embodiment. The dimensions, materials, shapes, relative positions, etc. of the components described in each embodiment are merely illustrative examples, and are not intended to limit the scope of the present invention, unless otherwise specified. Each element constituting the present invention may be configured with the same material so that multiple elements are shared by one material, or conversely, the function of one material may be shared by multiple materials. [Industrial Applicability]

[0070] The light emitting device of the present disclosure can be used as a light source for projectors, vehicle headlights, lighting devices, communication devices, laser processing devices, and the like. [Explanation of symbols]

[0071] 10: light emitting element, 20: case, 30: light-transmitting member, 40: main lens, 50: secondary lens, 100: light emitting device

Claims

1. a plurality of light emitting elements, each of which is a laser element; one or more reflectors; A base including a bottom portion on which the plurality of light-emitting elements and the one or more reflectors are arranged, and a frame portion surrounding the plurality of light-emitting elements in a top view; A plate-shaped cover joined to an upper surface of the frame; a lens array joined to an upper surface of the cover, the lens array including a plate-shaped portion and a plurality of lens-shaped portions protruding upward from the plate-shaped portion, the plurality of lens-shaped portions being integrated; Equipped with the frame portion has a first outer side surface, a second outer side surface opposite to the first outer side surface, a first inner side surface on the first outer side surface side, and a second inner side surface on the second outer side surface side and facing the first inner side surface, the first outer surface, the second outer surface, the first inner surface, and the second inner surface intersect with the top surface; The plurality of light-emitting elements emit light in a first direction that is a direction from a light exit surface to the first outer surface, the one or more reflectors are disposed at positions farther away from the plurality of light-emitting elements in the first direction and reflect light emitted from the plurality of light-emitting elements; the cover has a first side surface facing the same direction as the first outer side surface and a second side surface facing the same direction as the second outer side surface, and is joined to the frame portion such that a distance from the first outer side surface to the first side surface in the first direction is smaller than a distance from the second outer side surface to the second side surface in the first direction; The lens array is a light emitting device in which the lens shaped portions are positioned closer to the first outer surface than to the second outer surface, and light reflected by the one or more reflectors passes through the multiple lens shaped portions (excluding a form in which the distance from the first outer surface to the first inner surface is smaller than the distance from the second outer surface to the second inner surface).

2. A light-emitting device as described in claim 1, wherein, in the first direction, a ratio of the distance from the first inner surface to the first side surface to the distance from the first outer surface to the first inner surface is greater than a ratio of the distance from the second inner surface to the second side surface to the distance from the second outer surface to the second inner surface.

3. The light emitting device according to claim 1 , wherein a distance from the first inner surface to the first side surface in the first direction is greater than a distance from the second inner surface to the second side surface.

4. The plurality of light emitting elements include a first light emitting element, a second light emitting element, and a third light emitting element, 4. The light emitting device according to claim 1, wherein the plurality of lens shaped portions include a first lens shaped portion through which light emitted from the first light emitting element passes, a second lens shaped portion through which light emitted from the second light emitting element passes, and a third lens shaped portion through which light emitted from the third light emitting element passes.

5. The light emitting device according to claim 1 , wherein a bonding layer that bonds the cover and the lens array is made of an ultraviolet curing resin.

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