Light source device and display device

Abstract

Reduces color unevenness in the light emitted from the light source device. [Solution] The light source device comprises a first semiconductor laser element for red light, a second semiconductor laser element for green light, a third semiconductor laser element for blue light, a planar optical wave circuit that optically couples with the first, second, and third semiconductor laser elements and emits red, green, and blue laser light from the same port, a lens positioned on the optical axis of the planar optical wave circuit and collimating the red, green, and blue laser light, and a translucent member positioned on the optical axis of the planar optical wave circuit and having a second light incident surface into which the red, green, and blue laser light emitted from the lens is incident, wherein the diffusion angle of the red laser light is greater than the diffusion angle of the green laser light and the diffusion angle of the blue laser light, and the second light incident surface has a first diffraction grating in a region where a portion of the red laser light overlaps and in a region where the green and blue laser light do not overlap, the pitch of which decreases as it moves from the center of the red laser light outward in at least one of the short axis and long axis directions of the red laser light.

Description

Technical Field

[0001] The present disclosure relates to a light source device and a display device.

Background Art

[0002] Conventionally, a light source device that emits laser light and a display device including the light source device are known. For example, Patent Document 1 discloses a light source module having a waveguide type planar optical circuit.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] An embodiment according to the present disclosure aims to reduce color unevenness of light emitted from a light source device.

Means for Solving the Problems

[0005] A light source device according to one embodiment of the present disclosure includes a support member having an upper surface, a first semiconductor laser element that emits red laser light and is positioned on the upper surface, a second semiconductor laser element that emits green laser light and is positioned on the upper surface, a third semiconductor laser element that emits blue laser light and is positioned on the upper surface, a planar optical wave circuit positioned on the upper surface that optically couples with the first semiconductor laser element, the second semiconductor laser element, and the third semiconductor laser element and emits the red laser light, the green laser light, and the blue laser light from the same port, and a device positioned on the upper surface, located on the optical axis of the planar optical wave circuit, having a first optical incident surface and a first optical emission surface, and emitting the red laser light, the green laser light, and the blue laser light The device comprises a collimating lens and a translucent member having a second light incident surface located on the optical axis of the planar optical wave circuit, to which the red laser light, the green laser light, and the blue laser light emitted from the lens are incident, and a second light emission surface from which the red laser light, the green laser light, and the blue laser light are emitted, wherein the diffusion angle of the red laser light is greater than the diffusion angle of the green laser light and the diffusion angle of the blue laser light, and the second light incident surface has a first diffraction grating in a region where a portion of the red laser light overlaps and in a region where the green laser light and the blue laser light do not overlap, the pitch of which decreases as it moves from the center of the red laser light outward in at least one of the short axis and long axis directions of the red laser light. [Effects of the Invention]

[0006] According to the embodiments of this disclosure, color unevenness of the light emitted from the light source device can be reduced. [Brief explanation of the drawing]

[0007] [Figure 1] This is a schematic perspective view showing the overall configuration of the light source device according to the first embodiment. [Figure 2] This is a first schematic perspective view showing the configuration of the lens and the surrounding light-transmitting member of the light source device according to the first embodiment. [Figure 3] This is a second schematic perspective view showing the configuration of the lens and the surrounding light-transmitting member of the light source device according to the first embodiment. [Figure 4] This is a schematic top view showing the configuration of the lens and light-transmitting member included in the light source device according to the first embodiment. [Figure 5] This is a schematic diagram of the lens of the light source device according to the first embodiment, viewed from the first light incident surface side. [Figure 6] This is a schematic diagram of the lens of the light source device according to the first embodiment, viewed from the first light emission surface side. [Figure 7] This figure shows the red laser light, green laser light, and blue laser light after passing through the first light-emitting surface of the lens provided in the light source device according to the first embodiment. [Figure 8] This figure shows the light intensity distribution along the VIII-VIII line in Figure 7. [Figure 9] This figure shows the red laser light, green laser light, and blue laser light before they pass through the second light incident surface of the light-transmitting member of the light source device according to the first embodiment. [Figure 10] This figure shows the red laser light, green laser light, and blue laser light after passing through the second light-emitting surface of the light-transmitting member of the light source device according to the first embodiment. [Figure 11] This figure shows the light intensity distribution along the XI-XI line in Figure 10. [Figure 12] This is a first schematic perspective view showing the configuration of the lens and the surrounding light-transmitting member of the light source device according to the second embodiment. [Figure 13] This is a second schematic perspective view showing the configuration of the lens and the surrounding light-transmitting member of the light source device according to the second embodiment. [Figure 14] This is a schematic top view showing the configuration of the lens and light-transmitting member included in the light source device according to the second embodiment. [Figure 15] This figure shows the red laser light, green laser light, and blue laser light after passing through the first light-emitting surface of the lens provided in the light source device according to the second embodiment. [Figure 16] This figure shows the light intensity distribution along the XVI-XVI line in Figure 15. [Figure 17]A diagram showing red laser light, green laser light, and blue laser light before passing through the second light incident surface of the light transmissive member included in the light source device according to the second embodiment. [Figure 18] A diagram showing red laser light, green laser light, and blue laser light after passing through the second light exit surface of the light transmissive member included in the light source device according to the second embodiment. [Figure 19] A diagram showing the light intensity distribution along the XIX-XIX line in FIG. 18. [Figure 20] A schematic perspective view of the light transmissive member included in the light source device according to the third embodiment as viewed from the second light incident surface side. [Figure 21] A schematic perspective view showing the light transmissive member included in the light source device according to the third embodiment as viewed from the second light exit surface side. [Figure 22] A schematic diagram showing the configuration of the display device according to the fourth embodiment.

Embodiments for Carrying Out the Invention

[0008] The light source device and the display device according to the embodiments of the present disclosure will be described in detail with reference to the drawings. However, the embodiments shown below are examples of the light source device and the display device for embodying the technical idea of the present disclosure, and are not limited thereto. In addition, the dimensions, materials, shapes, relative arrangements, etc. of the components described in the embodiments are not intended to limit the scope of the present disclosure only thereto, but are merely illustrative examples, unless there is a description to limit to a specific form. Note that the sizes, positional relationships, etc. of the members shown in each drawing may be exaggerated for clarity of explanation. Also, in the following description, the same names and reference numerals indicate the same or equivalent members, and detailed descriptions will be omitted as appropriate. "Arranging" is not limited to the case of direct contact, but also includes the case of arranging indirectly, for example, via other members.

[0009] In each drawing, as a direction expression, orthogonal coordinates including the X-axis, Y-axis, and Z-axis are used. The X-axis, Y-axis, and Z-axis are orthogonal to each other. The direction in which the arrow points in the X direction along the X-axis is denoted as the +X direction, and the opposite direction of the +X direction is denoted as the -X direction. The direction in which the arrow points in the Y direction along the Y-axis is denoted as the +Y direction, and the opposite direction of the +Y direction is denoted as the -Y direction. The direction in which the arrow points in the Z direction along the Z-axis is denoted as the +Z direction, and the opposite direction of the +Z direction is denoted as the -Z direction. However, the terms indicating these specific directions and positions are only used to make the relative directions and positions in the referenced drawing easier to understand. These direction expressions do not limit the orientation during the use of the light source device and the display device according to the embodiment. The orientation during the use of the light source device and the display device according to the embodiment is arbitrary.

[0010] In the embodiments shown below, "along the X-axis, Y-axis, and Z-axis" includes that the object has an inclination within a range of ±5 degrees with respect to these axes. "Along the X-axis, Y-axis, and Z-axis" preferably includes that the object has an inclination within a range of ±3 degrees or ±1 degree with respect to these axes. In the embodiment, each of "orthogonal" and "perpendicular" may include an error within ±5 degrees with respect to 90 degrees. Each of "orthogonal" and "perpendicular" preferably may include an error within ±3 degrees or within ±1 degree with respect to 90 degrees. "Plan view" means viewing an object from the normal direction of the light-transmitting member included in the light source device according to the embodiment, for example, the +Y direction.

[0011] [First Embodiment] <Configuration of the Light Source Device According to the First Embodiment> The configuration of the light source device according to the first embodiment will be described with reference to Figures 1 to 6. Figure 1 is a schematic perspective view showing the overall configuration of the light source device 100 according to the first embodiment. Figure 2 is a first schematic perspective view showing the configuration around the lens 4 and light-transmitting member 5 of the light source device 100. Figure 3 is a second schematic perspective view showing the configuration around the lens 4 and light-transmitting member 5 of the light source device 100. Figure 4 is a schematic top view showing the configuration around the lens 4 and light-transmitting member 5 of the light source device 100. Figure 5 is a schematic view of the lens 4 of the light source device 100 as seen from the first light incident surface 41 side. Figure 6 is a schematic view of the lens 4 of the light source device 100 as seen from the first light emission surface 42 side.

[0012] As shown in Figures 1 to 4, the light source device 100 includes a support member 1 having an upper surface 11, a first semiconductor laser element 21 that emits red laser light Lr and is positioned on the upper surface 11, a second semiconductor laser element 22 that emits green laser light Lg and is positioned on the upper surface 11, and a third semiconductor laser element 23 that emits blue laser light Lb and is positioned on the upper surface 11. The light source device 100 also includes a planar lightwave circuit (PLC) 3 positioned on the upper surface 11 that is optically coupled with the first semiconductor laser element 21, the second semiconductor laser element 22, and the third semiconductor laser element 23, and emits red laser light Lr, green laser light Lg, and blue laser light Lb from the same port. Furthermore, the light source device 100 is positioned on the upper surface 11 and on the optical axis 3C of the planar light wave circuit 3, and has a first light incident surface 41 and a first light emission surface 42, and has a lens 4 that collimates the red laser light Lr, the green laser light Lg, and the blue laser light Lb. In addition, the light source device 100 includes a light-transmitting member 5 positioned on the optical axis 3C of the planar light wave circuit 3, which has a second light incident surface 51 into which the red laser light Lr, the green laser light Lg, and the blue laser light Lb emitted from the lens 4 are incident, and a second light emission surface 52 that emits the red laser light Lr, the green laser light Lg, and the blue laser light Lb.

[0013] In this embodiment, the second light incident surface 51 has a first diffraction grating 53 in a region where a portion of the red laser light Lr overlaps, but where the green laser light Lg and blue laser light Lb do not overlap. The first diffraction grating 53 has a pitch that narrows as it extends from the center LC of the red laser light Lr outward in the direction of the short axis of the red laser light Lr. In the examples shown in Figures 1 to 4, the direction of the short axis of the red laser light Lr corresponds to the X direction.

[0014] In this specification, the beam diameter is defined as follows: The beam diameter is the total width up to the point where the laser light intensity becomes 5% when the peak intensity of the laser light is set to 100%. Therefore, the "region where a portion of the red laser light Lr overlaps and where the green laser light Lg and blue laser light Lb do not overlap" means the region where the red laser light Lr exists outside the beam diameter of the green laser light Lg and blue laser light Lb. Preferably, the beam diameter is the total width up to the point where the laser light intensity becomes 3% or 1% when the peak intensity of the laser light is set to 100%.

[0015] In the light source device 100, the material of the first semiconductor laser element 21 that emits red laser light Lr is different from the materials of the second semiconductor laser element 22 that emits green laser light Lg and the third semiconductor laser element 23 that emits blue laser light Lb. For example, the first semiconductor laser element 21 contains an arsenide semiconductor or a phosphide semiconductor, while the second semiconductor laser element 22 and the third semiconductor laser element 23 contain nitride semiconductors. The first semiconductor laser element 21, the second semiconductor laser element 22, and the third semiconductor laser element 23 are end-face emitting laser elements. Therefore, due to the differences in the material systems constituting the semiconductor laser elements, the effective refractive index of the semiconductor laser elements differs, and the height and lateral dimensions of the core also differ. In this case, the divergence angles of the red laser light Lr, the green laser light Lg, and the blue laser light Lb are different.

[0016] In the light source device 100, the diffusion angle of the red laser light Lr is larger than that of the green laser light Lg and the blue laser light Lb. As a result, the red laser light Lr emitted from the planar light wave circuit 3 has a larger divergence angle relative to the green laser light Lg and blue laser light Lb emitted from the planar light wave circuit 3. Consequently, a portion of the red laser light Lr emitted from the planar light wave circuit 3 is offset and does not overlap with the green laser light Lg and blue laser light Lb emitted from the planar light wave circuit 3. This offset may cause color unevenness in the light emitted from the light source device 100. Furthermore, if optical elements are provided outside the light source device 100 to correct this offset and ensure that each laser beam overlaps, the number of components constituting the light source device 100 will increase due to the placement of the optical elements. This increase in the number of components can lead to an increase in the overall size of the system. It is desirable for the optical axes of each laser beam to be close together at the time the laser beam is emitted from the light source device 100, as this facilitates coaxial design and contributes to miniaturization of the system.

[0017] In this embodiment, the first diffraction grating 53 of the translucent member 5 directs the red laser beam Lr inward, reducing the spread of the red laser beam Lr in the short axis direction. As a result, the red laser beam Lr overlaps with the green laser beam Lg and the blue laser beam Lb, respectively, reducing color unevenness of the light emitted from the light source device 100. Furthermore, since the laser beams can be superimposed without providing optical elements outside the light source device 100, the light source device 100 can be miniaturized.

[0018] The light source device 100 is a device that emits white laser light Lw, which is a mixture of red laser light Lr, green laser light Lg, and blue laser light Lb. The red laser light Lr is light with a peak wavelength in the range of 605 nm to 750 nm. The green laser light Lg is light with a peak wavelength in the range of 495 nm to 570 nm. The blue laser light Lb is light with a peak wavelength in the range of 420 nm to 494 nm. The white laser light Lw is light with a color temperature or correlated color temperature of 1000 K to 10000 K.

[0019] In the example shown in Figures 1 to 4, the light source device 100 has a submount 6 that supports a first semiconductor laser element 21, a second semiconductor laser element 22, and a third semiconductor laser element 23. The submount 6 is positioned on the upper surface 11 of the support member 1. The first semiconductor laser element 21, the second semiconductor laser element 22, and the third semiconductor laser element 23 are positioned on the upper surface 61 of the submount 6. The submount 6 includes wiring 62.

[0020] The support member 1 is manufactured by molding ceramics or metal using a mold, etc. In the light source device 100, the light-transmitting member 5 can also serve as the side surface of the support member 1, thus reducing the number of parts. The support member 1 may also be manufactured, for example, by injection molding a resin that has light-shielding properties against red laser light Lr, green laser light Lg, and blue laser light Lb. By using resin for the support member 1, costs can be reduced compared to using ceramics or metal.

[0021] It is preferable to use, for example, a III-V compound semiconductor for each of the first semiconductor laser element 21, the second semiconductor laser element 22, and the third semiconductor laser element 23. Examples of III-V compound semiconductors include those containing at least one of GaN, InGaN, AlGaN, GaAs, AlGaInP, InGaAsP, and AlGaAs. For the submount 6, for example, aluminum nitride, diamond, graphite, or silicon carbide can be used.

[0022] The support member 1 has a first side wall 12, a second side wall 13 opposite to the first side wall 12, and a third side wall 14. The third side wall 14 connects the first side wall 12 and the second side wall 13. The light-transmitting member 5 is located opposite to the third side wall 14 and is attached to the first side wall 12 and the second side wall 13. The support member 1 is sealed by a lid member 7 facing the upper surface 11.

[0023] The planar optical circuit 3 is manufactured, for example, by etching silica glass deposited on a silicon substrate. The lens 4 is manufactured, for example, by molding a resin material or glass material that is transparent to red laser light Lr, green laser light Lg, and blue laser light Lb.

[0024] Lens 4 has an aspherical first light incident surface 41. This allows for correction of wavefront aberration. As shown in Figure 5, the first light incident surface 41 includes a first refractive region 411 that reduces the wavefront aberration of red laser light Lr, and a second refractive region 412 that reduces the wavefront aberrations of green laser light Lg and blue laser light Lb, respectively. This reduces wavefront aberration. The first refractive region 411 and the second refractive region 412 have different amounts of sag.

[0025] As shown in Figure 6, the lens 4 includes a second diffraction grating 43 on the first light-emitting surface 42. The second diffraction grating 43 includes a first diffraction region 431 that diffracts red laser light Lr to reduce chromatic aberration, and a second diffraction region 432 that diffracts green laser light Lg and blue laser light Lb, respectively, to reduce chromatic aberration. The chromatic aberration of each color is reduced by the inclusion of the first diffraction region 431 and the second diffraction region 432 in the second diffraction grating 43. The diffraction grating has different periods in the first diffraction region 431 and the second diffraction region 432. Multiple grooves are formed in the diffraction grating, each having a period in the X direction and extending in the Z direction.

[0026] Furthermore, the second refraction region 412 is not limited to the wavefront aberrations of the green laser light Lg and the blue laser light Lb, and the wavefront aberration of at least one of the green laser light Lg and the blue laser light Lb may be reduced. The second diffraction region 432 is not limited to the green laser light Lg and the blue laser light Lb, and at least one of the green laser light Lg and the blue laser light Lb may be diffracted.

[0027] The magnitude of the refraction angle of light passing through a refraction region at a given wavelength and the magnitude of the diffraction angle of light passing through a diffraction region are different from each other. This is because the wavelength dependence of the refraction angle and the diffraction angle are inversely related. The refraction angle is larger as the wavelength decreases, and the diffraction angle is smaller as the wavelength decreases. Laser light passing through lens 4 passes through the first refraction region 411 or the second refraction region 412 of the first light incident surface 41, and each laser beam is refracted at a predetermined refraction angle for each color. At this time, the refraction angle differs for each color, and the diffraction angle is larger as the wavelength decreases. Next, the laser light passes through the first diffraction region 431 and the second diffraction region 432 of the first light emission surface 42, and each laser beam is diffracted at a predetermined diffraction angle for each color. At this time, the diffraction angle differs for each color, and the diffraction angle is smaller as the wavelength decreases. Therefore, by including the second diffraction grating 43 in the lens 4, the difference in deflection angle for each color (i.e., the difference in refraction angle for each color) caused by refraction in the first refractive region 411 and the second refractive region 412 is canceled out by diffraction at the second diffraction grating 43. As a result, the light source device 100 can correct the chromatic aberration of the red laser light Lr, green laser light Lg, and blue laser light Lb emitted from the lens 4.

[0028] The translucent member 5 has a first diffraction grating 53 on the second light incident surface 51 side. It may also have a metasurface 54 on the second light emission surface 52 side. The translucent member 5 is manufactured, for example, by etching glass that is translucent to red laser light Lr, green laser light Lg, and blue laser light Lb. In the examples shown in Figures 1 to 3, the translucent member 5 has a substantially rectangular shape in plan view. However, the shape of the translucent member 5 in plan view is not limited to a substantially rectangular shape and can be changed as appropriate.

[0029] The first diffraction grating 53 is provided in a region of the second light incident surface 51 that overlaps with at least a portion of the red laser light Lr in the short axis direction, and in a region that does not overlap with the green laser light Lg and the blue laser light Lb. The pitch of the first diffraction grating 53 narrows as you move outward in the short axis direction from the center LC of the red laser light Lr. In other words, it is a binary diffraction grating.

[0030] In the first diffraction grating 53 of the translucent member 5, the diffraction angle increases as the position of the elliptical beam in the incident laser light moves towards the outer periphery by narrowing the pitch of the diffraction grating. As a result, the outer rays of the red laser light Lr are deflected inward and overlap with the green laser light Lg and the blue laser light Lb.

[0031] The translucent member 5 may include, at least, a metasurface 54 in a region that overlaps with the red laser light Lr on the second light emission surface 52 and does not overlap with the green laser light Lg and the blue laser light Lb on the second light emission surface 52, wherein the refraction angle increases as it extends outward from the center LC of the red laser light Lr in the direction of the short axis of the red laser light Lr. The metasurface 54 is provided on the opposite side of the first diffraction grating 53.

[0032] In the metasurface 54 of the translucent member 5, the diameter and height of the wavelength-order-of-size cylinder are gradually changed so that the refraction angle increases as the position of the elliptical beam in the incident laser moves towards the outer periphery. The metasurface 54 is an optical component with a structure in which wavelength-order-of-size cells (e.g., cylinders) are patterned on a flat plate. The metasurface 54 contains wavelength-order-of-size cells in a narrow area. By changing the diameter and height of the cells depending on the position, the amount of phase shift of the light can be controlled and the direction of the light can be changed. The metasurface 54 is preferably positioned as follows: That is, it is preferably positioned on the second light emission surface 52 at a position where the peak intensity of the red laser light Lr is less than 1%. This reduces the loss of the red laser light and allows the red laser light Lr, green laser light Lg, and blue laser light Lb to be efficiently superimposed.

[0033] <Operation of the light source device> In the examples shown in Figures 1 to 6, the red laser light Lr emitted from the first semiconductor laser element 21, the green laser light Lg emitted from the second semiconductor laser element 22, and the blue laser light Lb emitted from the third semiconductor laser element 23 are each incident on the planar lightwave circuit 3. The red laser light Lr, green laser light Lg, and blue laser light Lb guided by the planar lightwave circuit 3 are emitted from the same port of the planar lightwave circuit 3.

[0034] The red laser beam Lr emitted from the planar lightwave circuit 3 is incident on the lens 4 and exits from the lens 4 after passing through the first refractive region 411 and the first diffracted region 431 of the lens 4. The green laser beam Lg and blue laser beam Lb emitted from the planar lightwave circuit 3 are also incident on the lens 4 and exit from the lens 4 after passing through the second refractive region 412 and the second diffracted region 432 of the lens 4. In the example shown in Figure 4, the green laser beam Lg and the blue laser beam Lb almost overlap in a top view, so their respective symbols are shown together.

[0035] A portion of the red laser light Lr emitted from lens 4 is incident on the translucent member 5, passes through the first diffraction grating 53 and the metasurface 54, and is emitted from the translucent member 5. On the other hand, another portion of the red laser light Lr emitted from lens 4 is incident on the translucent member 5, and is emitted from the translucent member 5 without passing through either the first diffraction grating 53 or the metasurface 54.

[0036] The green laser light Lg and blue laser light Lb emitted from lens 4 are incident on the translucent member 5, respectively, and are emitted from the translucent member 5 without passing through either the first diffraction grating 53 or the metasurface 54.

[0037] In the optical path from when the light enters the translucent member 5 until it is emitted from the translucent member 5, the colors of the red laser light Lr, green laser light Lg, and blue laser light Lb are mixed. The light source device 100 emits white laser light Lw, which is a mixture of the colors of the red laser light Lr, green laser light Lg, and blue laser light Lb.

[0038] The metasurface 54 of the translucent member 5 makes the red laser light Lr parallel. This reduces color unevenness in the light emitted from the light source device 100. In other words, the beam of the red laser light Lr can be emitted as collimated light while overlapping the green laser light Lg and the blue laser light Lb more than the overlap at the first light incident surface 41. Each laser beam is emitted from the planar optical wave circuit 3 with its optical axis aligned and passes through the lens 4 and the translucent member 5. The light source device 100 can emit white laser light Lw with an optical axis and beam diameter that are almost aligned.

[0039] <Operation of the light source device 100> The operation of the light source device 100 will be explained with reference to Figures 7 to 11. Figure 7 shows the red laser light Lr, green laser light Lg, and blue laser light Lb after passing through the first light emission surface 42 of the lens 4. Figure 8 shows the light intensity distribution along the line VIII-VIII in Figure 7. Figure 9 shows the red laser light Lr, green laser light Lg, and blue laser light Lb before passing through the second light incident surface 51 of the light-transmitting member 5. Figure 10 shows the red laser light Lr, green laser light Lg, and blue laser light Lb after passing through the second light emission surface 52 of the light-transmitting member 5. Figure 11 shows the light intensity distribution along the line XI-XI in Figure 10.

[0040] Figures 7, 9, and 10 schematically show the simulation results for red laser light (Lr), green laser light (Lg), and blue laser light (Lb) in a planar view. Figures 8 and 11 show the simulation results for the light intensity distribution.

[0041] The red laser light Lr shown in Figures 10 and 11 has a reduced portion that does not overlap with the green laser light Lg and blue laser light Lb in the short axis direction (X direction) compared to the red laser light Lr shown in Figures 7 and 8. This is because, as shown in Figure 9, when the red laser light Lr passes through the first diffraction grating 53, the component of the red laser light Lr that overlaps with the first diffraction grating 53 is directed inward. Furthermore, the component of the red laser light Lr that has passed through the first diffraction grating 53 passes through the metasurface 54, correcting its propagation direction, and resulting in a collimated red laser light Lr being extracted as a whole. As a result, in the light source device 100, the red laser light Lr overlaps with the green laser light Lg and blue laser light Lb, respectively, reducing color unevenness of the emitted light.

[0042] [Second Embodiment] Next, a display device according to the second embodiment will be described. Note that names and reference numerals identical to those used in the previously described embodiments indicate the same or identical components or configurations, and detailed explanations will be omitted as appropriate. This also applies to the embodiments described later.

[0043] <Configuration of the light source device according to the second embodiment> The configuration of the light source device according to the second embodiment will be described with reference to Figures 12 to 14. Figure 12 is a first schematic perspective view showing the configuration of the lens 4 and light-transmitting member 5 of the light source device 100a according to the second embodiment. Figure 13 is a second schematic perspective view showing the configuration of the lens 4 and light-transmitting member 5 of the light source device 100a. Figure 14 is a schematic top view showing the configuration of the lens 4 and light-transmitting member 5 of the light source device 100a.

[0044] In the light source device 100a according to this embodiment, the first diffraction grating 53a of the translucent member 5 is provided in a region of the second light incident surface 51 in the longitudinal direction where a portion of the red laser light Lr overlaps, and in a region where the green laser light Lg and the blue laser light Lb do not overlap. The pitch of the first diffraction grating 53a narrows as you move outward in the longitudinal direction from the center LC of the red laser light Lr. The metasurface 54a of the translucent member 5 is provided on the opposite side of the first diffraction grating 53a. These points differ between the light source device 100a and the light source device 100 according to the first embodiment. In the examples shown in Figures 12 to 14, the longitudinal direction corresponds to the Z direction.

[0045] In this embodiment, by reducing the spread of the red laser light Lr in the long axis direction, the red laser light Lr, green laser light Lg, and blue laser light Lb overlap. As a result, the color unevenness of the emitted light from the light source device 100a is reduced.

[0046] In this embodiment, the first refraction region 411 and the second refraction region 412 of the first light incident surface 41 are rotated by 90° compared to the first embodiment. That is, each region is aligned in the Z direction. Similarly, the first diffraction region 431 and the second diffraction region 432 of the first light emission surface 42 are also rotated by 90° compared to the first embodiment. That is, each region is aligned in the Z direction. The periodic direction of the diffraction grating formed in each region is the Z direction, and the grooves extend in the X direction.

[0047] <Operation of light source device 100a> The operation of the light source device 100a will be explained with reference to Figures 15 to 19. Figure 15 shows the red laser light Lr, green laser light Lg, and blue laser light Lb after passing through the first light emission surface 42 of the lens 4 of the light source device 100a. Figure 16 shows the light intensity distribution along the XVI-XVI line in Figure 15. Figure 17 shows the red laser light Lr, green laser light Lg, and blue laser light Lb before passing through the second light incident surface 51 of the light-transmitting member 5 of the light source device 100a. Figure 18 shows the red laser light Lr, green laser light Lg, and blue laser light Lb after passing through the second light emission surface 52 of the light-transmitting member 5 of the light source device 100a. Figure 19 shows the light intensity distribution along the XIX-XIX line in Figure 18.

[0048] Figures 15, 17, and 18 schematically show the simulation results for red laser light (Lr), green laser light (Lg), and blue laser light (Lb) in a planar view. Figures 16 and 19 show the simulation results for the light intensity distribution.

[0049] The red laser light Lr shown in Figures 18 and 19 has a reduced portion in the long axis direction (Z direction) that does not overlap with the green laser light Lg and the blue laser light Lb, compared to the red laser light Lr shown in Figures 15 and 16. As a result, in the light source device 100a, the red laser light Lr overlaps with the green laser light Lg and the blue laser light Lb, respectively, reducing color unevenness of the emitted light.

[0050] [Third Embodiment] Next, a display device according to the third embodiment will be described with reference to Figures 20 and 21. Figure 20 is a schematic perspective view of the light-transmitting member 5 of the light source device according to the third embodiment, viewed from the second light incident surface 51 side. Figure 21 is a schematic perspective view of the light-transmitting member 5 of the light source device according to the third embodiment, viewed from the second light emission surface 52 side.

[0051] In the light source device according to this embodiment, the second light incident surface 51 of the translucent member 5 has a first diffraction grating 53b in a region where a portion of the red laser light Lr overlaps and where the green laser light Lg and blue laser light Lb do not overlap, the pitch of which decreases as it moves outward from the center LC of the red laser light Lr in both the short axis direction and the long axis direction. Furthermore, the translucent member 5 includes at least a metasurface 54b in a region on the second light emission surface 52 that overlaps with the red laser light Lr and where the green laser light Lg and blue laser light Lb do not overlap, the refraction angle which increases as it moves outward from the center LC of the red laser light Lr in both the short axis direction and the long axis direction. These points differentiate the light source device according to this embodiment from the light source device 100 according to the first embodiment. In the examples shown in Figures 20 and 21, the short axis direction corresponds to the X direction, and the long axis direction corresponds to the Z direction.

[0052] In this embodiment, by reducing the spread of the red laser light Lr in both the short axis and long axis directions, the red laser light Lr, green laser light Lg, and blue laser light Lb overlap. This reduces color unevenness in the light emitted from the light source device.

[0053] In this embodiment, a vertical-cavity surface-emitting laser element can be used instead of an end-face-emitting semiconductor laser element. In this case, the shape of the laser beam emitted from the semiconductor laser element is approximately circular. Therefore, the short axis and long axis directions of the laser beam can be interpreted as the radial direction. The first diffraction grating 53b and the metasurface 54b contribute to the radial components in the direction parallel to and perpendicular to the upper surface 11 of the support member 1.

[0054] In the first to third embodiments, a configuration was described in which red laser light Lr, green laser light Lg, and blue laser light Lb are extracted from the Y direction, but the disclosure is not limited thereto. For example, a riser mirror may be placed on the upper surface 11 of the support member 1 to raise each laser beam. In this case, a part of the lid member 7 may be a translucent member 5 having a second light incident surface 51 and a second light emission surface 52, or the translucent member 5 may be placed on the light incident surface side or the light emission surface side of the lid member 7. In this case as well, the red laser light Lr, green laser light Lg, and blue laser light Lb are superimposed, reducing color unevenness of the light emitted from the light source device.

[0055] In the first to third embodiments, the light source device is not limited to a configuration including a first semiconductor laser element 21 that emits red laser light Lr, a second semiconductor laser element 22 that emits green laser light Lg, and a third semiconductor laser element 23 that emits blue laser light Lb. It can be applied when the diffusion angles of the laser light emitted from the first semiconductor laser element 21 and the laser light emitted from the second semiconductor laser element 22 are different. In other words, it can be applied even if there are only two semiconductor laser elements. By overlapping the first laser light and the second laser light, color unevenness of the light emitted from the light source device is reduced.

[0056] [Fourth Embodiment] Next, a display device according to the fourth embodiment will be described. Figure 22 is a schematic diagram showing the configuration of the display device 200 according to the fourth embodiment. The display device 200 according to this embodiment is a display device having a light source device 100 and a spatial modulator 210. The light source device 100 emits white laser light Lw. The spatial modulator 210 spatially modulates the white laser light Lw emitted from the light source device 100. The display device 200 displays an image using the white laser light emitted from the light source device 100.

[0057] In the example shown in Figure 22, the display device 200 is a head-mounted display (HMD) worn by an observer, which displays an image in a way that is visible to the observer. Note that the display device 200 is not limited to the light source device 100, and may also include the light source device 100a according to the second embodiment or the light source device according to the third embodiment.

[0058] In the example shown in Figure 22, the display device 200 includes a condensing lens 220 that transmits light modulated by a spatial modulator 210, and a light guide member 230 that guides the light that has passed through the condensing lens 220. Furthermore, the display device 200 includes a first HOE (Holographic Optical Device) 240 that couples light to the light guide member 230, and a second HOE 250 that causes light to be emitted from the light guide member 230.

[0059] The light source device 100, the spatial modulator 210, and the focusing lens 220 are arranged, for example, on the temples of the spectacle-type support. The light guide member 230, the first HOE 240, and the second HOE 250 are arranged on the frame of the spectacle-type support, or on spectacle lenses etc. arranged on the frame.

[0060] The spatial modulator 210 spatially modulates white laser light Lw to form image light Im, which constitutes an image that can be viewed by the wearer U of the display device 200. The image light Im passes through the focusing lens 220 and is incident on the light guide member 230. The image light Im incident on the light guide member 230 is deflected by the first HOE 240 and coupled to the light guide member 230. The image light Im coupled to the light guide member 230 is guided through the inside of the light guide member 230. Of the image light Im guided through the inside of the light guide member 230, the image light Im that reaches the second HOE 250 is deflected by the second HOE 250 and emitted from the light guide member 230. The image light Im emitted from the light guide member 230 is incident on the wearer U's eyes. The wearer U can view the image according to the incident image light Im.

[0061] The light source device 100 can reduce color unevenness of the light emitted from the light source device. As a result, the display device 200 can display a color image with reduced white light unevenness using white laser light Lw, which is a mixture of the colors of the first laser light L1, the second laser light L2, and the third laser light L3.

[0062] The display device 200 is not limited to an HMD, but may also be an AR (Augmented Reality) glass, a VR (Virtual Reality) glass, a projector, a head-up display (HUD), etc.

[0063] Although preferred embodiments have been described in detail above, the invention is not limited to the embodiments described above, and various modifications and substitutions can be made to the embodiments described above without departing from the scope of the claims.

[0064] The ordinal numbers, quantities, and other figures used in the description of the embodiments are all illustrative to specifically illustrate the technology of this disclosure, and this disclosure is not limited to the illustrative figures. Furthermore, the connection relationships between the components are illustrative to specifically illustrate the technology of this disclosure, and are not limited to the connection relationships that realize the functions of this disclosure.

[0065] The light source device of this disclosure can reduce color unevenness of the light emitted from the light source device. For this reason, the light source device of this disclosure can be suitably used as a light source device in various devices, apparatuses, or systems that use laser light. For example, the light source device of this disclosure can be suitably used as a light source device in display devices such as projectors and head-up displays, or head-mounted display devices. Furthermore, the light source device of this disclosure can also be used as a light source device and display device in lighting equipment, lighting systems such as smart lighting and energy-saving lighting, drawing devices mounted on vehicles and aircraft, spatial three-dimensional drawing devices, underwater drawing systems, etc.

[0066] The aspects of this disclosure are, for example, as follows: <Item 1> A support member having an upper surface; a first semiconductor laser element that emits red laser light and is positioned on the upper surface; a second semiconductor laser element that emits green laser light and is positioned on the upper surface; a third semiconductor laser element that emits blue laser light and is positioned on the upper surface; a planar optical wave circuit positioned on the upper surface that optically couples with the first semiconductor laser element, the second semiconductor laser element, and the third semiconductor laser element and emits the red laser light, the green laser light, and the blue laser light from the same port; a lens positioned on the upper surface, located on the optical axis of the planar optical wave circuit, having a first light incident surface and a first light emission surface, and collimating the red laser light, the green laser light, and the blue laser light; and The light source device comprises a light-transmitting member located on the optical axis of the planar optical circuit, having a second light incident surface into which the red laser light, the green laser light, and the blue laser light emitted from the lens are incident, and a second light emission surface from which the red laser light, the green laser light, and the blue laser light are emitted, wherein the diffusion angle of the red laser light is greater than the diffusion angle of the green laser light and the diffusion angle of the blue laser light, and the second light incident surface has a first diffraction grating in a region where a portion of the red laser light overlaps and in a region where the green laser light and the blue laser light do not overlap, the pitch of which decreases as it moves from the center of the red laser light outward in at least one of the short axis and long axis directions of the red laser light. <Item 2> The light-transmitting member is the light source device according to <Item 1>, wherein the translucent member includes at least a metasurface in the region overlapping with the red laser light on the second light-emitting surface and in the region not overlapping with the green laser light and the blue laser light on the second light-emitting surface, the refraction angle of which increases as it moves outward from the center of the red laser light in at least one of the short axis and long axis directions of the red laser light. <Item 3> The light source device according to <Item 2>, wherein the first diffraction grating is provided in at least the region in the short axis direction on the second light incident surface in which a portion of the red laser light overlaps and in the region in which the green laser light and the blue laser light do not overlap, the pitch of the first diffraction grating becomes narrower as the red laser light moves outward in the short axis direction from the center of the red laser light, and the metasurface is provided on the opposite side of the first diffraction grating. <Item 4> The light source device according to <Item 2>, wherein the first diffraction grating is provided in at least the region in the longitudinal direction of the second light incident surface in which a portion of the red laser light overlaps and in the region in which the green laser light and the blue laser light do not overlap, the pitch of the first diffraction grating becomes narrower as the red laser light moves outward in the longitudinal direction from the center of the red laser light, and the metasurface is provided on the opposite side of the first diffraction grating. <Item 5> The lens is a light source device according to any one of <Item 1> to <Item 4>, wherein the first light incident surface is aspherical. <Clause 6> The light source device according to <Clause 5> comprises a first refraction region that reduces the wavefront aberration of the red laser light and a second refraction region that reduces the wavefront aberration of at least one of the green laser light and the blue laser light. <Clause 7> The lens is a light source device according to any one of <Clause 1> to <Clause 6>, wherein the lens includes a second diffraction grating on the first light emitting surface. <Clause 8> The light source device according to any one of <Clause 1> to <Clause 7>, wherein the support member has a first side wall, a second side wall opposite to the first side wall, and a third side wall, the light-transmitting member is located opposite to the third side wall and attached to the first side wall and the second side wall, and the support member is sealed by a cover member facing the upper surface. <Item 9> A support member having an upper surface; a first semiconductor laser element that emits a first laser beam and is positioned on the upper surface; a second semiconductor laser element that emits a second laser beam and is positioned on the upper surface; a planar optical wave circuit positioned on the upper surface that optically couples the first semiconductor laser element and the second semiconductor laser element and emits the first laser beam and the second laser beam from the same port; a lens positioned on the upper surface, located on the optical axis of the planar optical wave circuit, having a first optical incident surface and a first optical emission surface, and collimating the first laser beam and the second laser beam; and the optical A light source device comprising a light-transmitting member located on the axis and having a second light incident surface into which the first laser beam and the second laser beam emitted from the lens are incident, and a second light emission surface from which the first laser beam and the second laser beam are emitted, wherein the diffusion angle of the first laser beam is greater than the diffusion angle of the second laser beam, and the second light incident surface has a first diffraction grating in a region where a portion of the first laser beam overlaps and in a region where the second laser beam does not overlap, the pitch of which decreases as it moves from the center of the first laser beam outward in at least one of the short axis and long axis directions of the first laser beam. <Item 10> A display device comprising a light source device as described in any one of <Item 1> to <Item 9> above, and a spatial modulator. [Explanation of Symbols]

[0067] 1. Support member 3. Planar optical wave circuit 3C optical axis 4 lenses 5 Translucent material 6 Submount 11 Top side 21. First Semiconductor Laser Element 22 Second semiconductor laser element 23 Third Semiconductor Laser Element 41 First light incidence surface 42 First light exit surface 43 Second diffraction grating 51 Second light incidence surface 52 Second light exit surface 53, 53a, 53b First diffraction grating 54, 54a, 54b Metasurface 61 Top surface 62 Wiring 100, 100a light source device 200 Display device 210 Spatial modulator 220 Focusing Lens 230 Light guide member 240 1st HOE 250 Second HOE 411 First refractive region 412 Second refractive region 431 First diffraction region 432 Second diffraction region Lr red laser light Lg green laser light Lb blue laser light Lw White Laser Light

Claims

1. A support member having an upper surface, A first semiconductor laser element that emits red laser light is positioned on the upper surface, A second semiconductor laser element that emits green laser light is positioned on the upper surface, A third semiconductor laser element that emits blue laser light is positioned on the upper surface, A planar optical wave circuit is arranged on the upper surface and optically coupled with the first semiconductor laser element, the second semiconductor laser element, and the third semiconductor laser element, and emits the red laser light, the green laser light, and the blue laser light from the same port. A lens is positioned on the upper surface, located on the optical axis of the planar optical wave circuit, having a first light incident surface and a first light emission surface, and collimating the red laser light, the green laser light, and the blue laser light. The light-transmitting member comprises a second light incident surface located on the optical axis of the planar light wave circuit, to which the red laser light, the green laser light, and the blue laser light emitted from the lens are incident, and a second light emission surface from which the red laser light, the green laser light, and the blue laser light are emitted, The diffusion angle of the red laser light is greater than the diffusion angle of the green laser light and the diffusion angle of the blue laser light. The light source device has a first diffraction grating in which the pitch narrows from the center of the red laser beam outward from at least one of the short axis and long axis directions of the red laser beam, in a region where a portion of the red laser beam overlaps and in a region where the green laser beam and the blue laser beam do not overlap.

2. The light source device according to claim 1, wherein the light-transmitting member includes at least a metasurface in the region overlapping with the red laser light on the second light-emitting surface and in the region not overlapping with the green laser light and the blue laser light on the second light-emitting surface, wherein the refraction angle increases as you move away from the center of the red laser light to at least one of the short axis and long axis directions of the red laser light.

3. The first diffraction grating is provided in at least the region in the short axis direction of the second light incident surface where a portion of the red laser light overlaps, and where the green laser light and the blue laser light do not overlap. As the red laser beam moves from the center outward in the short axis direction, the pitch of the first diffraction grating becomes narrower. The light source device according to claim 2, wherein the metasurface is provided on the opposite side of the first diffraction grating.

4. The first diffraction grating is provided in at least the region in the longitudinal direction of the second light incident surface where a portion of the red laser light overlaps, and in the region where the green laser light and the blue laser light do not overlap. As the red laser beam moves from the center outward in the direction of the long axis, the pitch of the first diffraction grating becomes narrower. The light source device according to claim 2, wherein the metasurface is provided on the opposite side of the first diffraction grating.

5. The light source device according to any one of claims 1 to 4, wherein the lens has an aspherical first light incident surface.

6. The light source device according to claim 5, wherein the first light incident surface comprises a first refractive region that reduces the wavefront aberration of the red laser light and a second refractive region that reduces the wavefront aberration of at least one of the green laser light and the blue laser light.

7. The light source device according to any one of claims 1 to 4, wherein the lens includes a second diffraction grating on the first light emitting surface.

8. The support member has a first side wall, a second side wall opposite to the first side wall, and a third side wall. The light-transmitting member is located on the opposite side of the third side wall and is attached to the first side wall and the second side wall. The light source device according to any one of claims 1 to 4, wherein the support member is sealed by a lid member facing the upper surface.

9. A support member having an upper surface, A first semiconductor laser element that emits a first laser beam is positioned on the upper surface, A second semiconductor laser element that emits a second laser beam is positioned on the upper surface, A planar optical wave circuit is arranged on the upper surface, optically coupling the first semiconductor laser element and the second semiconductor laser element, and emitting the first laser beam and the second laser beam from the same port, A lens is positioned on the upper surface, located on the optical axis of the planar optical wave circuit, having a first light incident surface and a first light emission surface, and collimating the first laser beam and the second laser beam. The light-transmitting member is located on the optical axis of the planar light wave circuit and has a second light incident surface into which the first laser beam and the second laser beam emitted from the lens are incident, and a second light emission surface from which the first laser beam and the second laser beam are emitted. The diffusion angle of the first laser beam is greater than the diffusion angle of the second laser beam, The light source device has a first diffraction grating in the region where a portion of the first laser beam overlaps and in the region where the second laser beam does not overlap, wherein the pitch of the first diffraction grating decreases as it moves from the center of the first laser beam outward in at least one of the short axis and long axis directions of the first laser beam.

10. A light source device according to any one of claims 1 to 4 and 9, A display device comprising a spatial modulator.

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