Light emitting device and projector

Abstract

To provide a light-emitting device capable of efficiently illuminating a region to be illuminated.SOLUTION: A light-emitting device comprises a base material and a plurality of resonance parts provided on a first surface of the base material. Each of the plurality of resonance parts includes a photonic crystal structure having a periodic structure. The plurality of resonance parts constitute a light-emitting region for emitting light resonating via the periodic structure and include a first resonance part and a second resonance part. A distance from the center of the light-emitting region to the second resonance part is longer than a distance from the center of the light-emitting region to the first resonance part. A resonant length of the second resonance part is longer than a resonant length of the first resonance part.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a light emitting device and a projector. [Background technology]

[0002] Light-emitting devices using photonic crystals have been known for some time. For example, Patent Document 1 listed below discloses a surface-emitting laser that includes a two-dimensional photonic crystal and a one-dimensional photonic crystal, and has a structure in which light propagating in the in-plane direction of the two-dimensional photonic crystal is reflected by the photonic band edge of the one-dimensional photonic crystal. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2009-43918 A Summary of the Invention [Problem to be solved by the invention]

[0004] It is being considered to construct a small projector using the above-mentioned surface light source. In this case, if the surface light source can be arranged in close proximity to the light modulation device, the light modulation device can be illuminated efficiently. However, in order to provide a space for cooling the light modulation device or a space for arranging various optical elements such as lenses, the surface light source and the light modulation device must be arranged at a predetermined distance from each other. For example, when the light modulation device is composed of a liquid crystal display element, a space for arranging a polarizing element is required between the surface light source and the liquid crystal display element.

[0005] If the light beam emitted from the surface light source is not a parallel light beam but a diverging light beam, the diameter and the outer shape of the light beam change as it moves away from the surface light source. Therefore, if the light modulation device is disposed at a position away from the surface light source, the outer shape of the light beam incident on the light modulation device is different from the outer shape of the light beam immediately after it is emitted from the surface light source. The shape of the image formation area of ​​the light modulation device is often rectangular, and even if the shape of the light emission area of ​​the surface light source is made rectangular accordingly, the outer shape of the light beam deforms in a direction approaching a circle as it moves away from the surface light source. As a result, there is a problem that the outer shape of the light beam does not match the shape of the image formation area of ​​the light modulation device, and the image formation area cannot be illuminated efficiently. [Means for solving the problem]

[0006] In order to solve the above problems, a light emitting device of one embodiment of the present invention comprises a substrate and a plurality of resonant portions provided on a first surface of the substrate, each of the plurality of resonant portions includes a photonic crystal structure having a periodic structure, the plurality of resonant portions form a light emitting region that emits light resonated by the periodic structure, and includes a first resonant portion and a second resonant portion, wherein the distance from the center of the light emitting region to the second resonant portion is longer than the distance from the center of the light emitting region to the first resonant portion, and the resonant length of the second resonant portion is longer than the resonant length of the first resonant portion.

[0007] In one embodiment of the light-emitting device of the present invention, the light-emitting region may have a plurality of divided regions concentrically divided from the center, the plurality of divided regions may include a first divided region and a second divided region, a plurality of the first resonating portions may be provided in the first divided region, a plurality of the second resonating portions may be provided in the second divided region, the resonance lengths of the first resonating portions in the first divided region may be equal to one another, and the resonance lengths of the second resonating portions in the second divided region may be equal to one another.

[0008] In the light emitting device according to one aspect of the present invention, the intensity distribution of the light flux emitted from the light emitting region may be higher at the periphery of the light emitting region than at the center of the light emitting region.

[0009] In the light emitting device according to one aspect of the present invention, the plurality of resonating portions may be provided on a first surface of the base via at least one intermediate base.

[0010] In one embodiment of the light-emitting device of the present invention, the at least one intermediate substrate may include a first intermediate substrate and a second intermediate substrate, the first resonating portion being provided on the first intermediate substrate, and the second resonating portion being provided on the second intermediate substrate.

[0011] In one embodiment of the light-emitting device of the present invention, the multiple resonating portions may include a plurality of the first resonating portions and a plurality of the second resonating portions, the multiple first resonating portions being provided on the first intermediate substrate, and the multiple second resonating portions being provided on the second intermediate substrate.

[0012] A projector of one embodiment of the present invention comprises an light emitting device of one embodiment of the present invention, an optical modulation device that modulates light emitted from the light emitting device in accordance with image information to generate image light, and a projection optical device that projects the image light emitted from the optical modulation device.

[0013] In the projector according to one aspect of the invention, the light emitting region may have a planar shape similar to a planar shape of an image forming region in the light modulation device.

[0014] The projector according to one aspect of the invention may further include a relay optical system provided between the light emitting device and the light modulation device.

[0015] The projector according to one aspect of the invention may further include a light guide provided between the light emitting device and the light modulation device. [Brief description of the drawings]

[0016] [Figure 1] FIG. 1 is a schematic configuration diagram of a projector according to a first embodiment. [Diagram 2]FIG. 2 is a plan view of the light emitting element according to the first embodiment. [Diagram 3] FIG. [Figure 4] 4 is a cross-sectional view of the resonator taken along line IV-IV in FIG. 3. [Diagram 5] 5 is a diagram showing a light distribution angle of light emitted from a resonator. FIG. [Figure 6] 11 is a diagram showing the light distribution angle of light emitted from a plurality of resonators located at different positions within a light-emitting region. FIG. [Figure 7] 4 is a diagram showing positions at which light emitted from a plurality of resonating portions reaches an image forming area of ​​the light modulation device. FIG. [Figure 8] 1A and 1B are diagrams illustrating the planar shape and intensity distribution of a light beam. [Figure 9] 11A and 11B are diagrams illustrating the planar shape and intensity distribution of a light beam in a light emitting device of a comparative example. [Figure 10] FIG. 11 is a plan view of a light emitting element according to a second embodiment. [Figure 11] 11 is a diagram showing the relationship between the distance from the center of the light-emitting region and the size of the resonance region. FIG. [Figure 12] FIG. 11 is a cross-sectional view of a light emitting device according to a third embodiment. [Figure 13] FIG. 13 is a cross-sectional view of a light emitting device according to a fourth embodiment. [Figure 14] FIG. 11 is a cross-sectional view of a light emitting device according to a modified example. [Figure 15] 2 is a cross-sectional view of a light emitting device showing a first configuration example of an electrode. [Figure 16] FIG. 4 is a cross-sectional view of a light emitting device showing a second configuration example of an electrode. [Figure 17] FIG. 13 is a schematic configuration diagram of a projector according to a fifth embodiment. [Figure 18] FIG. 13 is a schematic configuration diagram of a projector according to a sixth embodiment. [Figure 19] FIG. 1 is a perspective view showing a first example of a light guide. [Figure 20] FIG. 11 is a perspective view showing a second example of a light guide. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] [First embodiment] A first embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a schematic configuration diagram of a projector according to the present embodiment. In the drawings, the dimensions of the components may be shown on different scales in order to make the components easier to see.

[0018] 1, a projector 10 of this embodiment is a projection type image display device that projects an image onto a screen 11. The projector 10 includes a light emitting device 12, a light modulation device 13, and a projection optical device 14. The configuration of the light emitting device 12 will be described in detail later.

[0019] Hereinafter, the optical axis AX1 refers to the axis that coincides with the normal passing through the center of light-emitting region 12R in light-emitting device 12 and through which the chief ray of light flux L emitted from light-emitting region 12R passes. Below, the configuration of each part will be explained using an XYZ orthogonal coordinate system, with the X-axis being the axis parallel to the long side of light-emitting region 12R, which has a rectangular planar shape as viewed from the direction of optical axis AX1, the Y-axis being the axis parallel to the short side of the light-emitting region, and the Z-axis being the axis perpendicular to the X-axis and Y-axis. The Z-axis and optical axis AX1 are parallel to each other.

[0020] The light modulation device 13 modulates the light flux L emitted from the light emitting device 12 according to image information to generate image light. The light modulation device 13 has an incident side polarizing plate 16, a liquid crystal display element 17, and an exit side polarizing plate 18. When viewed from the Z-axis direction, the planar shape of the image forming region 17R of the liquid crystal display element 17 is rectangular. As described above, the planar shape of the light emitting region 12R of the light emitting device 12 is rectangular, and the planar shapes of the image forming region 17R and the light emitting region 12R are approximately similar to each other. The area of ​​the light emitting region 12R is the same as the area of ​​the image forming region 17R or slightly larger than the area of ​​the image forming region 17R.

[0021] The projection optical device 14 projects the image light emitted from the light modulation device 13 onto a projection surface such as a screen 11. The projection optical device 14 is composed of one or more projection lenses.

[0022] The light emitting device 12 will now be described. 1, the light emitting device 12 includes a light emitting element 20 and a heat sink 21. The light emitting element 20 has a first surface 20a and a second surface 20b, and emits a luminous flux L from the first surface 20a. The heat sink 21 is provided on the second surface 20b of the light emitting element 20 to dissipate heat generated by the light emitting element 20.

[0023] Fig. 2 is a plan view showing a schematic configuration of the light-emitting element 20. Fig. 3 is a plan view of the resonator unit 23. Fig. 4 is a cross-sectional view of the resonator unit 23 taken along line IV-IV in Fig. 3. Note that in Fig. 2, in order to make the drawing easier to see, only some of the resonator units 23 out of all the resonator units 23 included in the light-emitting region 12R are shown, and the other resonator units 23 are not shown.

[0024] 4, the light-emitting element 20 has a substrate 50 (base material), a laminate 51, a first electrode 52, and a second electrode 53. The laminate 51 has a reflective layer 55, a buffer layer 56, a photonic crystal structure 57, and a third semiconductor layer 58.

[0025] The substrate 50 is made of, for example, a silicon (Si) substrate, a gallium nitride (GaN) substrate, a sapphire substrate, or the like.

[0026] The reflective layer 55 is provided on the substrate 50. The reflective layer 55 is composed of, for example, a DBR (distribution Bragg reflector) layer. The reflective layer 55 is composed of, for example, a laminate in which AlGaN layers and GaN layers are alternately laminated, or a laminate in which AlInN layers and GaN layers are alternately laminated. The reflective layer 55 reflects light generated in a light emitting layer 66 (described later) of the photonic crystal structure 57 toward the second electrode 53 side.

[0027] In this specification, in the Z-axis direction which is the stacking direction of the laminate 51, when the light emitting layer 66 is used as a reference, the direction from the light emitting layer 66 to the second semiconductor layer 67 is described as "upward," and the direction from the light emitting layer 66 to the first semiconductor layer 65 is described as "downward." Furthermore, the "stacking direction of the laminate 51" is the direction in which the first semiconductor layer 65 and the light emitting layer 66 face each other, and hereinafter may be simply referred to as the "stacking direction."

[0028] The buffer layer 56 is provided on the reflective layer 55. The buffer layer 56 is made of a semiconductor material, for example, a Si-doped n-type GaN layer. In the example of Fig. 4, a mask layer 60 is provided on the buffer layer 56 for growing a film constituting a columnar section 62, which will be described later, in the manufacturing process of the light-emitting element 20. The mask layer 60 is made of, for example, a silicon oxide layer, a silicon nitride layer, or the like.

[0029] Photonic crystal structure 57 is a columnar structure provided on buffer layer 56. Photonic crystal structure 57 has a plurality of columnar portions 62 and a plurality of light propagation layers 63. Photonic crystal structure 57 can exhibit the effect of a photonic crystal, and confines light emitted by light emitting layer 66 in the in-plane direction of substrate 50 and emits it in the stacking direction. "In-plane direction of substrate 50" refers to a direction along a plane perpendicular to the stacking direction.

[0030] The planar shape of the photonic crystal structure 57 is a polygon, a circle, an ellipse, or the like. In this embodiment, as shown in Fig. 3, the planar shape of the photonic crystal structure 57 is a regular hexagon. The diameter of the photonic crystal structure 57 is on the order of nm, specifically, for example, 10 nm or more and 500 nm or less. As shown in Fig. 4, the columnar portion 62 is a nanostructure that constitutes the photonic crystal structure 57. The dimension of the photonic crystal structure 57 in the stacking direction, that is, the height H of the photonic crystal structure 57, is, for example, 0.1 µm or more and 5 µm or less.

[0031] Note that the "diameter of photonic crystal structure 57" refers to the diameter of a circle when the planar shape of photonic crystal structure 57 is a circle, and refers to the diameter of a minimum inclusive circle when the planar shape of photonic crystal structure 57 is not a circle. For example, when the planar shape of photonic crystal structure 57 is a polygon, the diameter of photonic crystal structure 57 is the diameter of the minimum circle that includes the polygon therein, and when the planar shape of photonic crystal structure 57 is an ellipse, the diameter of photonic crystal structure 57 is the diameter of the minimum circle that includes the ellipse therein.

[0032] The "center of photonic crystal structure 57" refers to the center of a circle when the planar shape of photonic crystal structure 57 is a circle, and refers to the center of a smallest including circle when the planar shape of photonic crystal structure 57 is a shape other than a circle. For example, when the planar shape of photonic crystal structure 57 is a polygon, the center of photonic crystal structure 57 is the center of the smallest circle that contains the polygon inside, and when the planar shape of photonic crystal structure 57 is an ellipse, the center of photonic crystal structure 57 is the center of the smallest circle that contains the ellipse inside.

[0033] As shown in FIG. 3, the photonic crystal structures 57 are arranged in a square lattice pattern on the buffer layer 56. The pitches Px, Py between two adjacent photonic crystal structures 57 are, for example, 1 nm or more and 500 nm or less. In the case of this embodiment, the pitch Px in the X-axis direction and the pitch Py in the Y-axis direction are equal to each other. In this manner, the photonic crystal structures 57 are arranged periodically at predetermined pitches Px, Py along the X-axis direction and the Y-axis direction which are orthogonal to each other. The pitch Px in the X-axis direction is the distance between the centers of two photonic crystal structures 57 adjacent to each other in the X-axis direction. The pitch Py in the Y-axis direction is the distance between the centers of two photonic crystal structures 57 adjacent to each other in the Y-axis direction. Note that the photonic crystal structures 57 do not necessarily have to be arranged in a square lattice pattern, and may be arranged in, for example, a rectangular lattice pattern, a triangular lattice pattern, or the like.

[0034] As shown in FIG. 4, the columnar section 62 has a first semiconductor layer 65, a light emitting layer 66, and a second semiconductor layer 67.

[0035] The first semiconductor layer 65 is provided on the buffer layer 56. The first semiconductor layer 65 is composed of, for example, an n-type GaN layer doped with Si.

[0036] The light emitting layer 66 is provided on the first semiconductor layer 65. The light emitting layer 66 is provided between the first semiconductor layer 65 and the second semiconductor layer 67. The light emitting layer 66 has a quantum well structure composed of, for example, a GaN layer and an InGaN layer. The light emitting layer 66 emits light when a current is injected through the first semiconductor layer 65 and the second semiconductor layer 67.

[0037] The second semiconductor layer 67 is provided on the light emitting layer 66. The second semiconductor layer 67 is a layer having a conductivity type different from that of the first semiconductor layer 65. The second semiconductor layer 67 is composed of, for example, a p-type GaN layer doped with Mg. The first semiconductor layer 65 and the second semiconductor layer 67 function as cladding layers having a function of confining light within the light emitting layer 66.

[0038] The light propagation layer 63 is provided between adjacent columnar portions 62. In the example of FIG. 4, the light propagation layer 63 is provided on the mask layer 60. The refractive index of the light propagation layer 63 is lower than the refractive index of the light emitting layer 66. The light propagation layer 63 is composed of, for example, a silicon oxide layer, an aluminum oxide layer, a titanium oxide layer, or the like. The light generated in the light emitting layer 66 propagates through the light propagation layer 63.

[0039] As shown in Fig. 3, one resonator unit 23 is composed of a plurality of photonic crystal structures 57 arranged in a square lattice pattern. Also, as shown in Fig. 2, the plurality of resonator units 23 are arranged spaced apart from one another on the first surface 50a of the substrate 50. In other words, no photonic crystal structure 57 is provided between adjacent resonator units 23. The plurality of resonator units 23 constitute a light-emitting region 12R that emits light resonated by the periodic structure of the photonic crystal structure 57.

[0040] In two adjacent resonators 23, light resonating in one resonator 23 does not reach the other resonator 23. The distance G between adjacent resonators 23 is greater than the wavelength of light generated in the light-emitting layer 66. This allows the adjacent resonators 23 to be configured such that light resonating in one resonator 23 does not reach the other resonator 23.

[0041] A light absorbing portion that absorbs light may be provided between adjacent resonators 23. The light absorbing portion is made of a material having a band gap narrower than the band gap corresponding to the light resonating in the resonator 23. Examples of this type of material include InGaN and InN. The light absorbing portion is made of a columnar or wall-shaped crystal provided between adjacent resonators 23, for example. This prevents light resonating in one resonator 23 from reaching the other resonator 23.

[0042] Alternatively, a light reflecting portion that reflects light may be provided between adjacent resonator units 23. For example, a light reflecting portion can be formed by providing a columnar structure having a smaller pitch or diameter than the photonic crystal structure 57 that constitutes the resonator units 23 between adjacent resonator units 23. This prevents light resonating in one resonator unit 23 from reaching the other resonator unit 23 between the adjacent resonator units 23.

[0043] In the light emitting device 12, a pin diode is formed by a stack of a p-type second semiconductor layer 67, a light emitting layer 66 that is not doped with impurities, and an n-type first semiconductor layer 65. The band gaps of the first semiconductor layer 65 and the second semiconductor layer 67 are larger than the band gap of the light emitting layer 66. When a forward bias voltage for the pin diode is applied between the first electrode 52 and the second electrode 53 to inject a current, recombination of electrons and holes occurs in the light emitting layer 66, causing light emission.

[0044] The light generated in the light emitting layer 66 is propagated through the light propagation layer 63 in the in-plane direction of the substrate 50 by the first semiconductor layer 65 and the second semiconductor layer 67. At this time, the light forms a standing wave due to the effect of the photonic crystal of the photonic crystal structure 57, and is confined in the in-plane direction of the substrate 50. The confined light receives gain in the light emitting layer 66 and oscillates as a laser. That is, the light generated in the light emitting layer 66 resonates in the in-plane direction of the substrate 50 by the photonic crystal structure 57, and oscillates as a laser. Specifically, the light generated in the light emitting layer 66 resonates in the in-plane direction of the substrate 50 in the resonator 23 composed of a plurality of photonic crystal structures 57, and oscillates as a laser. Thereafter, the +1st order diffracted light and -1st order diffracted light generated by the resonance travel in the stacking direction (Z-axis direction) as laser light.

[0045] Of the laser light that travels in the stacking direction, the laser light that travels toward the reflective layer 55 side is reflected by the reflective layer 55 and travels toward the second electrode 53 side. This allows the light emitting device 12 to emit light from the second electrode 53 side.

[0046] The third semiconductor layer 58 is provided on the photonic crystal structure 57. The third semiconductor layer 58 is made of, for example, a p-type GaN layer doped with Mg.

[0047] The first electrode 52 is provided on the buffer layer 56 on the side of the photonic crystal structure 57. The first electrode 52 may be in ohmic contact with the buffer layer 56. In the example of FIG. 3, the first electrode 52 is electrically connected to the first semiconductor layer 65 via the buffer layer 56. The first electrode 52 is one of the electrodes for injecting a current into the light-emitting layer 66. As the first electrode 52, for example, a laminated film in which a Ti layer, an Al layer, and an Au layer are laminated in this order from the buffer layer 56 side is used.

[0048] The second electrode 53 is provided on the third semiconductor layer 58. The second electrode 53 may be in ohmic contact with the third semiconductor layer 58. The second electrode 53 is electrically connected to the second semiconductor layer 67. In the example of FIG. 4, the second electrode 53 is electrically connected to the second semiconductor layer 67 via the third semiconductor layer 58. The second electrode 53 is the other electrode for injecting a current into the light emitting layer 66. For example, ITO (Indium Tin Oxide) is used as the second electrode 53. The second electrode 53 provided on one of the adjacent photonic crystal structures 57 and the second electrode 53 provided on the other are electrically connected by wiring (not shown).

[0049] FIG. 5 is a diagram showing the light distribution angle of the light L0 emitted from the resonator 23. As shown in FIG. As shown in FIG. 3, in a plan view, the length Dx of the resonance unit 23 in the X-axis direction and the length Dy of the resonance unit 23 in the Y-axis direction are equal. In this way, when the length Dx and the length Dy of the resonance unit 23 are equal, as shown in FIG. 5, the light distribution angle θx along the X-axis direction of the light L0 emitted from the resonance unit 23 and the light distribution angle θy along the Y-axis direction are equal. In other words, by comparing the light distribution angle θx along the X-axis direction of the light L0 emitted from the resonance unit 23 and the light distribution angle θy along the Y-axis direction, it is possible to confirm whether the length Dx and the length Dy are equal. When the planar shape of the resonance unit 23 is a rotationally symmetric shape such as a square or a regular hexagon as in this embodiment, the light distribution angle of the light L0 emitted from the resonance unit 23 is rotationally symmetric about the optical axis AX0 as shown in FIG. The light distribution angle is defined as the angle between a light ray emitted from one light-emitting point O and spreading outward most and a normal line passing through the light-emitting point O.

[0050] 3, in a plan view, the outer shape of the resonator unit 23 is a square corresponding to a figure enclosed by straight lines connecting the centers of the photonic crystal structures 57 located at the outermost periphery among the multiple photonic crystal structures 57 constituting one resonator unit 23. The light emitted from the light emitting layer 66 resonates in each of the X-axis direction and the Y-axis direction in which the multiple photonic crystal structures 57 are arranged at a constant pitch in the resonator unit 23. That is, the light L0 resonates in two resonance directions.

[0051] Therefore, the resonance length in the X-axis direction of the resonator 23 corresponds to the length Dx of a straight line connecting the centers of the multiple photonic crystal structures 57 aligned in the X-axis direction. Similarly, the resonance length in the Y-axis direction of the resonator 23 corresponds to the length Dy of a straight line connecting the centers of the multiple photonic crystal structures 57 aligned in the Y-axis direction. In this embodiment, since the outer shape of the resonator 23 is a square, the resonance length in the X-axis direction and the resonance length in the Y-axis direction of the resonator 23 are equal to each other. Hereinafter, the length Dx in the X-axis direction and the length Dy in the Y-axis direction of the resonator 23 may be collectively referred to as the size of the resonator 23.

[0052] 2, in light-emitting region 12R, sizes Dx, Dy of multiple resonance units 23 gradually increase from the center toward the periphery of light-emitting region 12R. In other words, the resonance length in the X-axis direction and the resonance length in the Y-axis direction of multiple resonance units 23 gradually increase from the center toward the periphery of light-emitting region 12R. Moreover, parameters such as diameter, height, pitch, and arrangement of photonic crystal structure 57 of each resonance unit 23 are the same for all resonance units 23.

[0053] Any of the resonating units 23 located closer to the center of the light-emitting region 12R is defined as a first resonating unit 23A, and any of the resonating units 23 located farther from the center of the light-emitting region 12R than the first resonating unit 23A is defined as a second resonating unit 23B. That is, the multiple resonating units 23 include the first resonating unit 23A and the second resonating unit 23B.

[0054] 2, the resonance unit 23 located at the center of the light-emitting region 12R is defined as the first resonance unit 23A, and the resonance unit 23 located fourth from the center of the light-emitting region 12R is defined as the second resonance unit 23B. In this case, the distance from the center of the light-emitting region 12R to the second resonance unit 23B is longer than the distance from the center of the light-emitting region 12R to the first resonance unit 23A, and the resonance length of the second resonance unit 23B is longer than the resonance length of the first resonance unit 23A.

[0055] In this embodiment, the resonance lengths of the multiple resonance units 23 located at the same distance from the center of the light-emitting region 12R are equal to each other. In Fig. 2, the curves connecting the multiple resonance units 23 having the same resonance length are shown as two-dot chain circles. There are many such circles, but Fig. 2 shows only three circles.

[0056] In this embodiment, the multiple resonators 23 having the same resonance length are arranged concentrically around the center of the light-emitting region 12R. That is, the ratio of the change in resonance length to the change in distance of the resonator 23 from the center of the light-emitting region 12R is constant in all directions as viewed from the center of the light-emitting region 12R. Note that the multiple resonators 23 having the same resonance length may be arranged, for example, in a concentric rectangular shape or a concentric elliptical shape around the center of the light-emitting region 12R. That is, the ratio of the change in resonance length to the change in distance of the resonator 23 from the center of the light-emitting region 12R may differ depending on the direction as viewed from the center of the light-emitting region 12R.

[0057] Due to the photonic crystal effect, the size of the resonator unit 23, i.e., the resonance length, affects the light distribution angle of the light L0 emitted from the resonator unit 23. Specifically, the larger the size of the resonator unit 23, the smaller the light distribution angle of the emitted light L0, and the smaller the size of the resonator unit 23, the larger the light distribution angle of the emitted light L0.

[0058] Fig. 6 is a diagram showing the light distribution angle of light L0 emitted from multiple resonator units 23 located at different positions P1, P2, P3, and P4 in the light-emitting region 12R. Fig. 6 shows only the light L0 emitted from the resonator units 23 located at four positions P1, P2, P3, and P4 aligned along the X-axis direction among the multiple resonator units 23 present in the light-emitting region 12R.

[0059] In the case of this embodiment, as described above, the size of the resonance portion 23, that is, the resonance length, gradually increases from the center to the periphery of the light-emitting region 12R. Therefore, as shown in FIG. 6, if the light distribution angle of the light L0 emitted from the resonance portion 23 at the position P1 is θ1, the light distribution angle of the light L0 emitted from the resonance portion 23 at the position P2 is θ2, the light distribution angle of the light L0 emitted from the resonance portion 23 at the position P3 is θ3, and the light distribution angle of the light L0 emitted from the resonance portion 23 at the position P4 is θ4, the magnitude relationship of these light distribution angles is θ1 > θ2 > θ3 > θ4. That is, the light distribution angle of the light L0 emitted from each resonance portion 23 gradually decreases from the center to the periphery of the light-emitting region 12R.

[0060] FIG. 7 is a diagram showing the positions where the light L0 emitted from each of the positions P1, P2, P3, and P4 in FIG. 6 reaches the image formation region 17R of the liquid crystal display element 17. As shown in FIG. 1, the light beam L emitted from the light-emitting device 12 passes through the incident-side polarizing plate 16 and enters the image formation region 17R of the liquid crystal display element 17 disposed at a position separated from the light-emitting device 12 by a distance Z1. At this time, assuming that the positions where the light L0 emitted from the resonance portions 23 at the positions P1, P2, P3, and P4 reach the image formation region 17R are the positions Q1, Q2, Q3, and Q4, respectively, and the distances from the center O1 of the image formation region 17R to each of the positions Q1, Q2, Q3, and Q4 are the distances R1, R2, R3, and R4, respectively, it is desirable that the magnitude relationship of these distances is R1 < R2 < R3 < R4. In other words, the arrival position of the light L0 emitted from the resonance portion 23 closer to the center of the light-emitting region 12R is preferably located inside without exceeding the arrival position of the light L0 emitted from the resonance portion 23 farther from the center of the light-emitting region 12R than the resonance portion 23.

[0061] Here, as a light-emitting device of a comparative example, assume a light-emitting device in which the light-emitting region has a plurality of resonance portions and the sizes (resonance lengths) of the plurality of resonance portions are the same. Note that the planar shape of the light-emitting region is a square. Fig. 9 is a diagram showing the cross-sectional shape perpendicular to the principal ray of the light beam L3 in the illuminated region and the intensity distribution in a light emitting device of a comparative example. The upper part of Fig. 9 shows the cross-sectional shape of the light beam L3, and the lower part of Fig. 9 shows the intensity distribution of the light beam. In addition to the cross-sectional shape of the light beam L3, the upper part of Fig. 9 also shows the intensity contour lines (isointensity lines).

[0062] In the light emitting device of the comparative example, the cross-sectional shape of the light flux L3 emitted from the square light emitting region changes from a square to a shape with rounded corners, as shown in Fig. 9. Also, the intensity distribution is high at the center of the illuminated region and low at the periphery of the illuminated region, and the intensity varies greatly depending on the position on the illuminated region.

[0063] In contrast, Fig. 8 is a diagram showing the cross-sectional shape perpendicular to the principal ray of the light beam L in the illuminated region and the intensity distribution in the light-emitting device 12 of this embodiment. The upper part of Fig. 8 shows the cross-sectional shape of the light beam L, and the lower part of Fig. 8 shows the intensity distribution of the light beam L. In addition to the cross-sectional shape of the light beam, the upper part of Fig. 8 also shows the intensity contour lines (isointensity lines). The dashed lines in the upper and lower parts of Fig. 8 show the cross-sectional shape and intensity distribution of the light beam L immediately after it is emitted from the light-emitting device 12. Here, for comparison with the comparative example, the planar shape of the light-emitting region 12R is assumed to be a square.

[0064] In the light-emitting device 12 of this embodiment, as shown in Fig. 8, the cross-sectional shape of the light flux L emitted from the light-emitting region 12R is not so rounded as in the comparative example, and is not so different from a square. In addition, the light emitted from the center of the light-emitting region 12R spreads widely, and the light emitted from the periphery of the light-emitting region 12R does not spread so much, so that the intensity distribution of the light flux L emitted from the light-emitting region 12R is slightly higher at the periphery of the light-emitting region 12R than at the center, but an intensity distribution with a substantially constant intensity is obtained regardless of the position on the illuminated region. In this way, the cross-sectional shape and intensity distribution of the light flux L immediately after emission from the light-emitting device 12 are sufficiently maintained even on the illuminated region.

[0065] As described above, according to the light emitting device 12 of the present embodiment, the resonance lengths of the multiple resonators 23 are made different and the light distribution angle is changed depending on the position on the light emitting region 12R, thereby making it possible to control the cross-sectional shape and intensity distribution of the light flux L in an illuminated region away from the light emitting device 12. In particular, in this embodiment, the light distribution angle of the light emitted from the resonators 23 located on the periphery of the light emitting region 12R is made smaller than the light distribution angle of the light emitted from the resonators 23 located in the center of the light emitting region 12R. Therefore, even on the image forming region 17R of the liquid crystal display element 17 away from the light emitting device 12, the cross-sectional shape of the light flux L immediately after emission from the light emitting device 12 can be sufficiently maintained.

[0066] As a result, according to the light emitting device 12 of the present embodiment, the cross-sectional shape of the emitted light flux L can be roughly matched to the shape of the image forming region 17R, thereby efficiently illuminating the light modulation device 13. Note that the cross-sectional shape of the light flux L changes depending on the light distribution angle and its distribution of the light flux L emitted from the light emitting device 12, the intensity and its distribution of the light flux L, the distance from the light emitting device 12, and the like.

[0067] Furthermore, since the projector 10 of the present embodiment is equipped with the light emitting device 12 that provides the above-mentioned effects, the light utilization efficiency is high and miniaturization is possible.

[0068] [Second embodiment] A second embodiment of the present invention will be described below with reference to FIG. The basic configuration of the light emitting device of the second embodiment is similar to that of the first embodiment, but the configuration of the multiple resonator units is different from that of the first embodiment, so a description of the entire light emitting device will be omitted. FIG. 10 is a plan view of the light emitting device according to the second embodiment. In FIG. 10, components common to those in FIG. 2 used in the first embodiment are given the same reference numerals, and description thereof will be omitted.

[0069] As shown in Fig. 10, in the light emitting device 30 of this embodiment, the light emitting region 30R has a plurality of divided regions that are divided concentrically and rectangularly from the center of the light emitting region 30R. In this embodiment, the plurality of divided regions include five divided regions, namely, a first divided region 30R1, a second divided region 30R2, a third divided region 30R3, a fourth divided region 30R4, and a fifth divided region 30R5, in that order from the center of the light emitting region 30R. Note that the "divided region" in the present invention does not mean that the components of the light emitting device 30 are physically divided, but means an individual region in which a plurality of resonating units 23 having the same size are arranged in the light emitting region 30R, as described later.

[0070] The multiple resonating units 23 include multiple first resonating units 23A, multiple second resonating units 23B, multiple third resonating units 23C, multiple fourth resonating units 23D, and multiple fifth resonating units 23E. The multiple first resonating units 23A are provided in the first division region 30R1. The multiple second resonating units 23B are provided in the second division region 30R2. The multiple third resonating units 23C are provided in the third division region 30R3. The multiple fourth resonating units 23D are provided in the fourth division region 30R4. The multiple fifth resonating units 23E are provided in the fifth division region 30R5.

[0071] In the present embodiment, as in the first embodiment, the planar shape of the resonator 23 is a square, and therefore the length Dx in the X-axis direction and the length Dy in the Y-axis direction of the resonator 23 are equal. Therefore, the length Dx in the X-axis direction and the length Dy in the Y-axis direction of the resonator 23 are collectively referred to as the size of the resonator 23. The size of the first resonator 23A is L1, the size of the second resonator 23B is L2, the size of the third resonator 23C is L3, the size of the fourth resonator 23D is L4, and the size of the fifth resonator 23E is L5.

[0072] The sizes of the plurality of resonance portions 23, that is, the resonance lengths, become longer from the center toward the periphery of the light-emitting region 30R. Therefore, the size relationship of the sizes of the respective resonance portions 23 is L1 < L2 < L3 < L4 < L5. Also, the sizes of the plurality of first resonance portions 23A within the first divided region 30R1, that is, the resonance lengths, are equal to each other, the sizes of the plurality of second resonance portions 23B within the second divided region 30R2, that is, the resonance lengths, are equal to each other, the sizes of the plurality of third resonance portions 23C within the third divided region 30R3, that is, the resonance lengths, are equal to each other, the sizes of the plurality of fourth resonance portions 23D within the fourth divided region 30R4, that is, the resonance lengths, are equal to each other, and the sizes of the plurality of fifth resonance portions 23E within the fifth divided region 30R5, that is, the resonance lengths, are equal to each other.

[0073] In the light-emitting device 12 of the first embodiment, the light-emitting region 12R is not divided, and the sizes of the plurality of resonance portions 23, that is, the resonance lengths, continuously become longer from the central portion toward the peripheral portion of the light-emitting region 12R. On the other hand, in the light-emitting device 30 of the present embodiment, the light-emitting region 30R is divided into a plurality of divided regions 30R1, 30R2, 30R3, 30R4, 30R5, and the closer the divided region is to the periphery of the light-emitting region 30R, the longer the sizes of the resonance portions 23 within the divided region, that is, the resonance lengths, are, and the sizes of the plurality of resonance portions 23 within each divided region, that is, the resonance lengths, are equal to each other. Simply put, in the light-emitting device 30 of the present embodiment, the sizes of the plurality of resonance portions 23, that is, the resonance lengths, become longer stepwise from the central portion toward the peripheral portion of the light-emitting region 30R. Other configurations of the light-emitting device 30 are the same as those of the first embodiment.

[0074] Also in the light-emitting device 30 of the present embodiment, since the shape of the light beam can be generally matched to the shape of the image formation region, the same effect as that of the first embodiment, such as being able to efficiently illuminate the optical modulation device, can be obtained.

[0075] Furthermore, in the present embodiment, since each of the divided regions 30R1, 30R2, 30R3, 30R4, and 30R5 is composed of resonator units 23 of the same size, it is easier to arrange a plurality of resonator units 23 at a higher density within the light-emitting region 30R than in the light-emitting device 12 of the first embodiment. This increases the packing rate of the resonator units 23 per light-emitting area, thereby increasing the light-emitting density.

[0076] In this embodiment, the light-emitting region 30R is divided into five divided regions 30R1, 30R2, 30R3, 30R4, and 30R5, but the light-emitting region 30R may be divided into more divided regions. The more the number of divisions, the more likely it is that the light-emitting device will have characteristics closer to those of the first embodiment in which the resonance length is continuously changed.

[0077] (Modification) Fig. 11 is a diagram showing the relationship between the distance from the center of the light emitting region and the size of the resonator, in which the horizontal axis represents the distance from the center of the light emitting region and the vertical axis represents the size of the resonator, i.e., the resonator length. 11, the graphs with symbols A and B correspond to the light emitting device 12 of the first embodiment, in which the size of the resonator changes continuously with the change in distance from the center of the light emitting region. In this case, the ratio of the change in size of the resonator to the change in distance from the center of the light emitting region may be constant regardless of the distance from the center of the light emitting region, as in the graph with symbol A, or may change depending on the distance from the center of the light emitting region, as in the graph with symbol B.

[0078] In Fig. 11, the graph C corresponds to the light emitting device 30 of the second embodiment, and the size of the resonator changes stepwise according to the change in distance from the center of the light emitting region. Also, as in the graph D, there may be some localized locations where the size of the resonator decreases as the position of the resonator moves away from the center. In this way, the size of the resonator does not necessarily have to increase monotonically with increasing distance from the center of the light emitting region, and it is sufficient that the size of the resonator increases in the peripheral side of the light emitting region compared to the resonator in the center side when viewed as a whole.

[0079] [Third embodiment] Hereinafter, a third embodiment of the present invention will be described with reference to FIG. The basic configuration of the light emitting device of the third embodiment is similar to that of the first embodiment, but the configuration relating to the base material is different from that of the first embodiment, so an overall description of the light emitting device will be omitted. FIG. 12 is a cross-sectional view of a light emitting device 40 according to the third embodiment. In FIG. 12, components common to those in the drawings used in the first embodiment are given the same reference numerals, and description thereof will be omitted.

[0080] As shown in FIG. 12, the light emitting device 40 of this embodiment includes a substrate 50 (base material), an intermediate substrate 41 (intermediate substrate), a laminate 51, a first electrode (not shown), and a second electrode 53. The laminate 51 includes a reflective layer 55, a buffer layer 56, a photonic crystal structure 57 (columnar structure), and a third semiconductor layer 58. The detailed configuration of the photonic crystal structure 57 is similar to that of the photonic crystal structure 57 of the first embodiment shown in FIG. 4. Although not shown, wiring is formed on each of the substrate 50 and the intermediate substrate 41, and the second electrode 53 is electrically connected to the wiring of the substrate 50 through the wiring formed on the intermediate substrate 41. In addition, the first electrode is electrically connected to the wiring of the substrate 50 through, for example, the wiring formed on the intermediate substrate 41. Alternatively, the first electrode may be electrically connected to the wiring of the substrate 50 from the rear surface of the intermediate substrate 41.

[0081] In this embodiment, the multiple resonating units 23 are provided on the first surface 50a of the substrate 50 via multiple intermediate substrates 41. That is, the multiple intermediate substrates 41 are provided on the first surface 50a of the substrate 50, and each of the multiple resonating units 23 is provided on each of the multiple intermediate substrates 41. The multiple intermediate substrates 41 include a first intermediate substrate 41A (first intermediate substrate) and a second intermediate substrate 41B (second intermediate substrate).

[0082] As in the first embodiment, the resonance unit 23 located at the center O of the light-emitting region 12R is referred to as the first resonance unit 23A, and the resonance unit 23 located away from the center O of the light-emitting region 12R is referred to as the second resonance unit 23B. The distance from the center of the light-emitting region 12R to the second resonance unit 23B is longer than the distance from the center of the light-emitting region 12R to the first resonance unit 23A, and the resonance length of the second resonance unit 23B is longer than the resonance length of the first resonance unit 23A. In the case of this embodiment, as in FIG. 4 shown in the first embodiment, the size of the resonance unit 23, i.e., the resonance length, gradually increases from the center to the periphery of the light-emitting region 12R.

[0083] In this embodiment, the first resonating unit 23A is provided on a first intermediate substrate 41A, and the second resonating unit 23B is provided on a second intermediate substrate 41B. That is, the first resonating unit 23A and the second resonating unit 23B are provided on different intermediate substrates 41A and 41B.

[0084] The intermediate substrate 41 is made of a material such as silicon (Si), gallium nitride (GaN), sapphire, etc. The substrate 50 is made of a material such as silicon (Si), gallium nitride (GaN), sapphire, aluminum nitride (AlN), silicon carbide (SiC), etc. The other configuration of the light emitting device 40 is similar to that of the first embodiment.

[0085] In this embodiment as well, since the shape of the light beam can be roughly matched to the shape of the image forming area, the same effect as in the first embodiment can be obtained, that is, the light modulation device can be efficiently illuminated.

[0086] Furthermore, according to the configuration of this embodiment, in the manufacturing process of the light emitting device 40, a method can be adopted in which, after each resonator unit 23 is formed on the intermediate substrate 41, each resonator unit 23 is transferred to a predetermined position on the substrate 50 together with the intermediate substrate 41. This allows the light emitting device 40 to be manufactured efficiently with a high yield.

[0087] [Fourth embodiment] Hereinafter, a fourth embodiment of the present invention will be described with reference to FIG. The basic configuration of the light emitting device of the fourth embodiment is similar to that of the second embodiment, but the configuration relating to the base material is different from that of the second embodiment, so a description of the entire light emitting device will be omitted. FIG. 13 is a cross-sectional view of a light emitting device 43 according to the fourth embodiment. In FIG. 13, components common to those in the previous embodiment are designated by the same reference numerals, and description thereof will be omitted.

[0088] As shown in FIG. 13, in the light emitting device 40 of this embodiment, similarly to the third embodiment, the multiple resonator units 23 are provided on the first surface 50a of the substrate 50 via the multiple intermediate substrates 41. That is, the multiple intermediate substrates 41 are provided on the first surface 50a of the substrate 50, and each of the multiple resonator units 23 is provided on each of the multiple intermediate substrates 41. The multiple intermediate substrates 41 include a first intermediate substrate 41A (first intermediate substrate) and a second intermediate substrate 41B (second intermediate substrate). In this embodiment, although not shown, wiring is formed on the substrate 50 and each of the multiple intermediate substrates 41, and the second electrode 53 of each of the multiple resonator units 23 is electrically connected to the wiring of the substrate 50 via the wiring formed on each of the multiple intermediate substrates 41. The first electrode is electrically connected to the wiring of the substrate 50, for example, via the wiring formed on the intermediate substrate 41. Alternatively, the first electrode may be electrically connected to the wiring of the substrate 50 from the rear surface of each of the multiple intermediate substrates 41.

[0089] In this embodiment, the light-emitting region 30R has a plurality of divided regions 30R1 and 30R2, similar to FIG. 10 of the second embodiment. In this embodiment, the plurality of divided regions include a first divided region 30R1 and a second divided region 30R2 in order from the center O of the light-emitting region 30R. The plurality of resonating units 23 include a plurality of first resonating units 23A and a plurality of second resonating units 23B. The plurality of first resonating units 23A are provided in the first divided region 30R1. The plurality of second resonating units 23B are provided in the second divided region 30R2. The size of the plurality of resonating units 23, i.e., the resonance length, is gradually increased from the center to the periphery of the light-emitting region 30R.

[0090] In this embodiment, the number of first intermediate substrates 41A provided in the first divided region 30R1 is the same as the number of first resonating units 23A. That is, one first resonating unit 23A is provided on one first intermediate substrate 41A. Similarly, the number of second intermediate substrates 41B provided in the second divided region 30R2 is the same as the number of second resonating units 23B. One second resonating unit 23B is provided on one second intermediate substrate 41B. The other configuration of the light emitting device 40 is similar to that of the first embodiment.

[0091] In this embodiment, the shape of the light beam can be roughly matched to the shape of the image forming area, so that the light modulation device can be efficiently illuminated, and the same effect as in the first embodiment can be obtained. Moreover, since a method can be adopted in which the resonator units 23 are formed on the intermediate substrate 41, the intermediate substrate 41 is cut out, and each resonator unit 23 is transferred together with the intermediate substrate 41 to a predetermined position on the substrate 50, the light emitting device 43 can be efficiently manufactured with a high yield, and the same effect as in the third embodiment can be obtained.

[0092] The light emitting device 43 of this embodiment may have the following modified configuration. FIG. 14 is a cross-sectional view of a light emitting device 45 according to a modified example. 14, in a light emitting device 45 of the modified example, a plurality of first resonator units 23A are provided on a single first intermediate substrate 41C, and a plurality of second resonator units 23B are provided on a single second intermediate substrate 41D. That is, in the light emitting device 45 of the modified example, a plurality of resonator units 23 having the same size are provided on a single intermediate substrate 41. The resonator units 23 are separated from each other by providing a gap between adjacent resonator units 23. In addition, a second electrode 53 located on an upper portion of a photonic crystal structure 57 is electrically connected between adjacent resonator units 23.

[0093] Moreover, the following two configuration examples may be adopted for the configuration of the first electrode and the second electrode. FIG. 15 is a cross-sectional view of a light emitting device 47 showing a first configuration example of the electrodes. As shown in FIG. 15, in the light emitting device 47 of the first configuration example, the second electrode 53 (p electrode) is formed on the upper surface of the photonic crystal structure 57 via a third semiconductor layer 58. The first electrode 71 (n electrode) is formed on the intermediate substrate 41 via a reflective layer 55 and a buffer layer 56. The first electrode 71 (n electrode) is electrically connected to a wiring 72 formed on the side of the intermediate substrate 41. The adjacent second electrodes 53 are electrically connected to each other by a wiring (not shown) made of, for example, an ITO layer. The connection between the first electrode 71 and the wiring 72 can be realized by patterning a metal film using, for example, a lift-off method.

[0094] FIG. 16 is a cross-sectional view of a light-emitting device 49 showing a second configuration example of the electrodes. As shown in FIG. 16, the position of the first electrode (n-electrode) of the light emitting device 49 of the second configuration example is different from that of the first configuration example. In the case of the second configuration example, a conductive material such as n-type GaN doped with Si is used as the intermediate substrate 74. In addition, an n-type reflective layer having conductivity, such as a DBR layer of n-type GaN / AlInN doped with Si, is used as the reflective layer 55. This allows the intermediate substrate 74 to have the function of the first electrode (n-electrode). The buffer layer 56 is composed of an n-type GaN layer doped with Si. The intermediate substrate 74 is disposed on the wiring 73 formed on the substrate 50. In addition, in the case of the second configuration example, it is necessary to use an insulating substrate such as an AlN substrate or a SiC substrate as the substrate 50.

[0095] In the second configuration example, unlike the first configuration example, there is no need to form the wiring 72 connected to the first electrode along the thickness direction of the intermediate substrate 41. This simplifies the mounting structure and mounting work when mounting the intermediate substrate 74 on the substrate 50. In addition, the arrangement density of the light-emitting elements can be increased, resulting in a light-emitting device with high luminous flux density.

[0096] [Fifth embodiment] In the following fifth and sixth embodiments, other configuration examples of the projector to which the light emitting device of the invention can be applied will be described. The basic configuration of the projectors of the fifth and sixth embodiments is substantially the same as that of the projector of the first embodiment. Therefore, a description of the basic configuration will be omitted, and only the differences will be described. FIG. 17 is a schematic configuration diagram of a projector according to the fifth embodiment. In FIG. 17, the same components as those in FIG. 1 used in the first embodiment are denoted by the same reference numerals, and the description thereof will be omitted.

[0097] As shown in FIG. 17, the projector 32 of the fifth embodiment further includes a relay optical system 33 provided between the light emitting device 12 and the light modulation device 13. The relay optical system 33 includes an incident side lens 34, a relay lens 35, and an exit side lens 36. The incident side lens 34 and the exit side lens 36 are configured to be optically conjugate with each other. As a result, the relay optical system 33 transmits the light beam image incident on the incident side lens 34, i.e., the intensity distribution of the light beam L, to the exit side lens 36 with the same size, or with an enlarged or reduced size, and emits the light beam from the exit side lens 36. FIG. 17 shows an example of the relay optical system 33 that transmits the light beam image by enlarging it.

[0098] Therefore, the intensity distribution of the light beam L illuminating the image forming region 17R of the liquid crystal display element 17 is approximately equal to the intensity distribution of the light beam L incident on the entrance-side lens 34. In other words, when illuminating the image forming region 17R with a light beam having a cross-sectional shape matching the image forming region 17R of the liquid crystal display element 17 and a substantially uniform intensity distribution, it is necessary to cause the light beam L, which has a different size from the light beam incident on the image forming region 17R but has the same cross-sectional shape and intensity distribution, to be incident on the entrance-side lens 34.

[0099] In the projector 32 of the present embodiment, the light emitting device 12 of the above embodiment is used, so that the light flux L can be efficiently incident on the relay optical system 33 arranged at a position away from the light emitting device 12.

[0100] By providing the projector 32 with the relay optical system 33, even if the size of the light emitting region 12R of the light emitting device 12 is significantly different from the size of the image forming region 17R of the liquid crystal display element 17, it is possible to easily form a light flux that matches the size of the image forming region 17R. In addition, since the light modulation device 13 can be disposed away from the light emitting device 12, the effect of heat emitted from the light emitting device 12 on the light modulation device 13 can be reduced.

[0101] Generally, light that has passed through an optical system such as the relay optical system 33 generates vignetting, with the intensity being high in the vicinity of the optical axis AX1 and decreasing as it moves away from the optical axis AX1. However, when the light-emitting device 12 of the above embodiment is used, as shown in Fig. 8, the intensity of the light emitted from the peripheral portion of the light-emitting region 12R is higher than the intensity of the light emitted from the center, so that the effect of vignetting caused by the relay optical system 33 is mitigated, and it is easy to obtain an image with less uneven brightness.

[0102] [Sixth embodiment] Fig. 18 is a schematic configuration diagram of a projector according to a sixth embodiment. Fig. 19 is a perspective view showing a first example of a light guide. Fig. 20 is a perspective view showing a second example of a light guide. In FIG. 18, the same components as those in FIG. 1 used in the first embodiment are denoted by the same reference numerals, and the description thereof will be omitted.

[0103] As shown in FIG. 18, a projector 38 of the sixth embodiment further includes a light guide 39 provided between the light emitting device 12 and the light modulation device 13.

[0104] As the light guide 39, for example, a light guide 39A made of a solid rod-shaped body made of a light-transmitting medium such as glass is used as shown in Fig. 19. Alternatively, as shown in Fig. 20, a light guide 39B made of a hollow tubular body in which a reflective mirror is arranged in a tubular shape with the reflective surface facing inward is used. Also, a light guide having the same opening size and shape at the entrance end and the exit end may be used, or a tapered light guide having an opening size that increases from the entrance end to the exit end, or a tapered light guide having an opening size that decreases from the entrance end to the exit end may be used.

[0105] The opening shapes of the incident end 39a and the exit end 39b of the light guide 39 are both rectangular and are set to be approximately similar to the light emitting region 12R of the light emitting device 12 and the image forming region 17R of the liquid crystal display element 17. The opening size of the incident end 39a of the light guide 39 is preferably the same as or slightly larger than the light emitting region 12R. The opening size of the exit end 39b of the light guide 39 is preferably the same as or slightly larger than the image forming region 17R of the liquid crystal display element 17.

[0106] In the projector 38 of the present embodiment, the light emitting device 12 of the above embodiment is used, so that the light flux L can be efficiently incident on the light guide 39 disposed at a position away from the light emitting device 12.

[0107] Furthermore, the light flux L incident on the light guide 39 is emitted with its intensity distribution homogenized by multiple reflections on the interface or inner wall surface of the light guide 39. This can further homogenize the intensity distribution of the light flux L, and the liquid crystal display element 17 can be efficiently illuminated by the light flux L having a substantially uniform intensity. Furthermore, since the light modulation device 13 can be disposed away from the light emitting device 12, the effect of heat generated from the light emitting device 12 on the light modulation device 13 can be reduced.

[0108] The technical scope of the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention. For example, in the above embodiment, it is assumed that the light emitting device emits a light flux of uniform intensity, but the present invention can also be applied to a light emitting device in which the emission intensity is not uniform within the light emitting region. By changing the light distribution angle of the light emitted from each resonator in consideration of the emission intensity of the light flux, the cross-sectional shape of the light flux can be controlled.

[0109] In the third and fourth embodiments, the first resonator is provided on the first intermediate substrate, and the second resonator is provided on the second intermediate substrate. Alternatively, a plurality of resonators including the first and second resonators may be provided on one intermediate substrate. In this case, the use of a substrate having high thermal conductivity, such as an AlN substrate or a SiC substrate, can promote heat dissipation from the light-emitting element, and thus the light-emitting efficiency and the amount of light emitted can be improved.

[0110] In the above embodiment, the light emitting layer is made of an InGaN material, but various semiconductor materials can be used as the light emitting layer depending on the wavelength of the emitted light. For example, AlGaN, AlGaAs, InGaAs, InGaAsP, InP, GaP, AlGaP, and other semiconductor materials can be used. In addition, the diameter or arrangement pitch of the photonic crystal structure can be changed as appropriate depending on the wavelength of the emitted light.

[0111] In the above embodiment, the photonic crystal structure is composed of a columnar structure protruding from the substrate, but the photonic crystal structure may have a plurality of holes arranged at a certain pitch in order to produce the photonic crystal effect. That is, each of the plurality of resonators may include a photonic crystal structure having a periodic structure, regardless of whether it is a columnar structure or holes.

[0112] In addition, the specific description of the shape, number, arrangement, material, etc. of each component of the light-emitting device and the projector is not limited to the above embodiment and can be changed as appropriate. In the above embodiment, an example was shown in which the light-emitting device according to the present invention is mounted on a projector using a transmissive liquid crystal display element as a light modulation device, but this is not limited to this. The light source device according to the present invention may be mounted on a projector using a reflective liquid crystal display element or a digital micromirror device as a light modulation device.

[0113] In the above embodiment, the light emitting device according to the present invention is mounted on a projector, but the present invention is not limited to this. The light emitting device according to the present invention can also be applied to lighting fixtures, automobile headlights, and the like. [Explanation of symbols]

[0114] Reference Signs List 10, 32, 38... projector, 12, 30, 40, 43, 45, 47, 49... light emitting device, 12R, 30R... light emitting region, 13... light modulation device, 17R... image forming region, 23... resonator, 23A... first resonator, 23B... second resonator, 23C... third resonator, 23D... fourth resonator, 23E... fifth resonator, 33... relay optical system, 39, 39A, 39B... light guide , 41,74...intermediate substrate (intermediate base material), 41A,41C...first intermediate substrate (first intermediate base material), 41B,41D...second intermediate substrate (second intermediate base material), 50...substrate (base material), 50a... First surface, 57...Photonic crystal structure, 30R1...First divided region, 30R2...Second divided region, 30R3...Third divided region, 30R4...Fourth divided region, 30R5...Fifth divided region.

Claims

1. A substrate; a plurality of resonating units provided on a first surface of the base material; each of the plurality of resonator units includes a photonic crystal structure having a periodic structure; the photonic crystal structure has a plurality of columnar portions and a light propagation layer provided between adjacent columnar portions of the plurality of columnar portions, Each of the plurality of columnar portions includes a first semiconductor layer, a second semiconductor layer having a conductivity type different from that of the first semiconductor layer, and a light emitting layer provided between the first semiconductor layer and the second semiconductor layer and including a quantum well structure; the light generated in the light emitting layer is propagated through the light propagation layer in an in-plane direction of the base material by the first semiconductor layer and the second semiconductor layer, and forms a standing wave due to the effect of the photonic crystal of the photonic crystal structure, and is confined in the in-plane direction; the trapped light is oscillated in the in-plane direction by the photonic crystal structure to produce laser oscillation, and +1st order diffracted light and −1st order diffracted light generated by resonance are emitted as laser light from the stacking direction of the columnar portion, the plurality of resonators constitute a light emitting region that emits light resonated by the photonic crystal structure, and include a first resonator and a second resonator; a distance from a center of the light emitting region to the second cavity portion is longer than a distance from the center of the light emitting region to the first cavity portion, A light emitting device, wherein a resonance length of the second resonance portion is longer than a resonance length of the first resonance portion.

2. The light emitting device according to claim 1 , wherein the photonic crystal structure is not provided between adjacent ones of the plurality of resonators.

3. The light emitting device according to claim 2 , further comprising a light absorbing portion provided between adjacent ones of the plurality of resonating portions and configured to absorb light.

4. The light emitting device according to claim 2 , further comprising a light reflecting portion provided between adjacent ones of the plurality of resonating portions and configured to reflect light.

5. The light emitting region has a plurality of divided regions that are concentrically divided from the center, The plurality of divided regions include a first divided region and a second divided region, A plurality of the first resonating portions are provided in the first divided region, and a plurality of the second resonating portions are provided in the second divided region, 5 . The light emitting device according to claim 1 , wherein the first resonating portions in the first division region have equal resonance lengths, and the second resonating portions in the second division region have equal resonance lengths.

6. The light emitting device according to claim 1 , wherein an intensity distribution of the light flux emitted from the light emitting region is higher at a periphery of the light emitting region than at a central portion of the light emitting region.

7. The light emitting device according to claim 1 , wherein the plurality of resonating portions are provided on the first surface of the base via at least one intermediate base.

8. The at least one intermediate substrate includes a first intermediate substrate and a second intermediate substrate; The first resonating portion is provided on the first intermediate base material, The light emitting device according to claim 7 , wherein the second resonator is provided on the second intermediate base material.

9. the plurality of resonating units include a plurality of the first resonating units and a plurality of the second resonating units, The plurality of first resonating units are provided on the first intermediate base material, The light emitting device according to claim 8 , wherein the plurality of second resonators are provided on the second intermediate base material.

10. A light emitting device according to any one of claims 1 to 9, a light modulation device that modulates the light emitted from the light emitting device in accordance with image information to generate image light; a projection optical device that projects the image light emitted from the light modulation device; A projector equipped with

11. The projector according to claim 10 , wherein a planar shape of the light emitting region is similar to a planar shape of an image forming region in the light modulation device.

12. The projector according to claim 10 , further comprising a relay optical system provided between the light emitting device and the light modulation device.

13. The projector according to claim 10 , further comprising a light guide provided between the light emitting device and the light modulation device.

Images