Optical waveguide substrate, light-emitting device, and electronic device

Abstract

An optical waveguide substrate (10) comprises a first core (11) and a base part (14) inside which the first core is positioned. The first core (11) has a first end surface (111) capable of emitting light in a first direction. The base part (14) has a first side surface (141) from which the first end surface is exposed, a first upper surface (142) connected to the first side surface, a second side surface (143) connected to the first upper surface and positioned below the first upper surface, and a first protrusion (144) positioned on the first upper surface. The first protrusion (144) is positioned below the first end surface (111). At least a portion of the first protrusion (144) is positioned between the first end surface (111) and the second side surface (143) in a plan view.

Description

Optical waveguide substrate, light-emitting device, and electronic device

[0001] The present disclosure relates to an optical waveguide substrate, a light-emitting device, and an electronic device.

[0002] Conventional optical waveguide substrates are described, for example, in Patent Document 1.

[0003] International Publication No. 2023 / 037702

[0004] The optical waveguide substrate according to the present disclosure includes a first core and a base. The first core has a first end face capable of emitting light in a first direction. The base has the first core located inside. The base has a first side face, a first upper face, a second side face, and a first convex portion. The first side face exposes the first end face. The first upper face is connected to the first side face. The second side face is connected to the first upper face and is located below the first upper face. The first convex portion is located on the first upper face. The first convex portion is located below the first end face. At least a part of the first convex portion is located between the first end face and the second side face in a plan view.

[0005] Furthermore, the light-emitting device according to the present disclosure includes an optical waveguide substrate, a first light-emitting element housed in a recess and emitting light incident on the first core, and a lid covering the recess.

[0006] Furthermore, the electronic device according to the present disclosure includes a light-emitting device and a display unit that performs display by the emitted light from the light-emitting device.

[0007] Perspective view of an optical waveguide substrate according to an embodiment of the present disclosure. Enlarged perspective view of main part A in FIG. 1. Side view of the optical waveguide substrate viewed from the first direction. Enlarged plan view of main part A in FIG. 1. Cross-sectional view taken at position B - B in FIG. 4. Cross-sectional view taken at position C - C in FIG. 4. Cross-sectional view at the same position as B - B in FIG. 3 in a modified example. Perspective view of a light-emitting device according to an embodiment of the present disclosure. Perspective view of an electronic device according to an embodiment of the present disclosure.

[0008] Embodiments of the present disclosure will be described below with reference to the drawings. However, for the sake of clarity, the drawings below are simplified to show only the main components necessary to describe the embodiments. Therefore, embodiments of the present disclosure may include any components not shown in the drawings. Furthermore, the drawings do not necessarily accurately represent the dimensional ratios of the actual components.

[0009] Regarding direction, the direction in which the first upper surface faces is defined as upward, and the opposite direction is defined as downward. Note that the direction in this disclosure does not mean the direction in which the device is actually used. For convenience, each direction is represented using a Cartesian coordinate system XYZ with upward being the positive side of the Z direction. In this disclosure, "plan view" means viewing from above (the positive side of the Z direction), and includes planar perspective.

[0010] In the following descriptions, expressions such as "constant," "orthogonal," "perpendicular," "parallel," and "equal" may be used. These expressions do not necessarily strictly mean "constant," "orthogonal," "perpendicular," "parallel," or "equal," respectively, and may allow for deviations such as manufacturing precision or installation precision. Numerical ranges indicated using "~" include the numbers before and after them as the lower and upper limits, respectively.

[0011] In optical waveguide substrates, there is a need to improve the quality of emitted light. Furthermore, even when light-emitting elements are not being emitted, there is a need for easy alignment of lenses and mirrors.

[0012] The optical waveguide substrate, light-emitting device, and electronic device disclosed herein can improve the quality of emitted light and facilitate the alignment of lenses and mirrors even when the light-emitting element is not emitting light.

[0013] [Optical waveguide substrate] As shown in Figures 1 to 7, the optical waveguide substrate 10 comprises a first core 11 and a base portion 14 in which the first core 11 is located. The first core 11 has a first end face 111 from which light can be emitted in a first direction (X direction). The base portion 14 has a first side surface 141 from which the first end face 111 is exposed, a first upper surface 142 connected to the first side surface 141, a second side surface 143 connected to the first upper surface 142 and located below the first upper surface 142, and a first protrusion 144 located on the first upper surface 142.

[0014] The first protrusion 144 is located below the first end face 111 (on the negative side in the Z direction). In other words, the uppermost part of the first protrusion 144 is located below the lowermost part of the first end face 111 (on the negative side in the Z direction). Also, as shown in Figure 4, at least a portion of the first protrusion 144 is located between the first end face 111 and the second side surface 143 in a plan view.

[0015] The first protrusion 144 is positioned, at least in part, between the first end face 111 and the second side surface 143 in a plan view, thereby scattering stray light from the light emitted from the first end face 111. This reduces the possibility that unwanted stray light will disrupt the beam shape of the light emitted from the first end face 111. For this reason, the optical waveguide substrate 10 of this disclosure having the first protrusion 144 can improve the quality of the light emitted from the first end face 111. Furthermore, because the first protrusion 144 is positioned between the first end face 111, which is the light emission end, and the second side surface 143, the light emission point is more easily visible even when no light is incident on the first core 11. This makes it easier to align lenses or mirrors that are to be installed at the light emission point.

[0016] As shown in Figures 1 to 4, the optical waveguide substrate 10 may further include a second core 12 and a third core 13 inside the base 14. The second core 12 may have a second end face 121 from which light can be emitted in a first direction. The third core 13 may have a third end face 131 from which light can be emitted in a first direction.

[0017] As shown in Figures 1 to 4, the first core 11, the second core 12, and the third core 13 may be arranged in this order inside the base 14. While not particularly limited, for example, the first core 11 may be used for blue light, the second core 12 for red light, and the third core 13 for green light. Alternatively, for example, the first core 11 may be used for green light, the second core 12 for red light, and the third core 13 for blue light. Furthermore, any or all of the first core 11, second core 12, and third core 13 may be used as cores that transmit light other than visible light, such as ultraviolet or infrared light.

[0018] As shown in Figure 3, the width w2 of the second end face 121 may be narrower than the width w1 of the first end face 111. This makes it easier to match the beam diameter of the red light at a point of equal distance from the output end face to the beam diameter of the green or blue light when the second core 12 is used for red light and the first core 11 is used for green or blue light. This is because red light has a longer wavelength than green and blue light, so the divergence angle of the output light tends to be larger at the output end face. Matching the beam diameter of the red light at a point of equal distance from the output end face to the beam diameter of the green or blue light makes it easier to adjust the resolution appropriately. In this disclosure, the divergence angle can also be referred to as the spread angle.

[0019] Similarly, the width w2 of the second end face 121 may be narrower than the width w3 of the third end face 131. This makes it easier to adjust the resolution when the second core 12 is used for red light and the third core 13 is used for green or blue light.

[0020] As shown in Figures 1 to 4, if the optical waveguide substrate 10 has a second core 12, the base portion 14 may have a second protrusion 145 located on the first upper surface 142. Similarly, if the optical waveguide substrate 10 has a third core 13, the base portion 14 may have a third protrusion 146 located on the first upper surface 142.

[0021] As shown in Figures 1 to 3, the second protrusion 145 may be located below the second end face 121. In other words, the uppermost part of the second protrusion 145 may be located below the lowest part of the first end face 111 (on the negative side in the Z direction). Similarly, the third protrusion 146 may be located below the third end face 131. In other words, the uppermost part of the third protrusion 146 may be located below the lowest part of the first end face 111 (on the negative side in the Z direction).

[0022] As shown in Figure 3, the width w5 of the second protrusion 145 may be narrower than the width w4 of the first protrusion 144. The width w6 of the third protrusion 146 may be wider than the width w5 of the second protrusion 145.

[0023] As shown in Figures 1 to 4, at least a portion of the second protrusion 145 may be located between the second end face 121 and the second side surface 143 in a plan view. Similarly, at least a portion of the third protrusion 146 may be located between the third end face 131 and the second side surface 143 in a plan view. This improves the quality of light emitted from the second end face 121 and the third end face 131. Furthermore, since the light emission point is more easily visible even when no light is incident on the second core 12 and the third core 13, it becomes easier to align lenses or mirrors that are to be installed at the light emission point.

[0024] As shown in Figures 1 to 7, the base portion 14 may have a substrate 15 having a second side surface 143 and a cladding 17 located on the substrate 15. In this case, the first core 11, the second core 12, and the third core 13 may be located within the cladding 17.

[0025] The substrate 15 may be made of conductive silicon, or it may be an insulating ceramic or resin. Examples of ceramics include aluminum oxide sintered bodies, mullite sintered bodies, silicon carbide sintered bodies, aluminum nitride sintered bodies, silicon nitride sintered bodies, and glass ceramic sintered bodies. Examples of resins include epoxy resin, polyimide resin, polyester resin, acrylic resin, phenolic resin, and fluororesin.

[0026] The cladding 17 and each core material may be light-transmitting materials. Specifically, the cladding 17 and each core material may be, for example, glass, resin, etc. More specifically, the cladding 17 material may be silicon dioxide (SiO₂). ２ ) and the material of each core may be silicon oxynitride (SiON), also known as silicon oxynitride. The refractive index of each core is greater than the refractive index of the cladding 17. The difference in refractive index between each core and the cladding 17 depends on the structure of each core, such as its shape, but can be set to, for example, 0.01 to 2.0. This provides an optical waveguide in which light propagates along each core.

[0027] As shown in Figure 7, the base portion 14 may have an insulating layer 16 between the substrate 15 and the cladding 17. The insulating layer 16 may be located across the entire surface between the substrate 15 and the cladding 17, or only in a portion thereof. The material of the insulating layer 16 may be glass, resin, ceramic, etc. The material of the insulating layer 16 may also be the same as the material of the cladding 17. In this case, the insulating layer 16 and the cladding 17 may be integrated.

[0028] The first side surface 141 may be composed of cladding 17 and substrate 15, as shown in Figure 2, or it may be composed of cladding 17 alone. Also, if the base 14 has an insulating layer 16 between substrate 15 and cladding 17, the first side surface 141 may be composed of cladding 17 alone, or it may be composed of cladding 17 and insulating layer 16, or it may be composed of cladding 17, insulating layer 16 and substrate 15.

[0029] The first upper surface 142 may be composed of a substrate 15, an insulating layer 16, or a cladding 17, as shown in Figure 2.

[0030] The first protrusion 144 may consist of one layer or multiple layers. The first protrusion 144, which consists of multiple layers, may have, for example, a first upper layer 144a and a first lower layer 144c, as shown in Figures 2, 5, and 7, and may further have a first intermediate layer 144b located between the first upper layer 144a and the first lower layer 144c, as shown in Figure 7. The fact that the first protrusion 144 is composed of multiple layers makes it easier to see the first protrusion 144 and facilitates high-precision alignment of the lens or mirror with respect to the first core 11.

[0031] Similar to the first protrusion 144, the second protrusion 145 and the third protrusion 146 may each consist of one layer or multiple layers. The second protrusion 145, which consists of multiple layers, may have, for example, a second upper layer 145a and a second lower layer 145c, as shown in Figures 2, 5, and 7, and may further have a second intermediate layer 145b located between the second upper layer 145a and the second lower layer 145c, as shown in Figure 7. The third protrusion 146, which consists of multiple layers, may have, for example, a third upper layer 146a and a third lower layer 146c, as shown in Figures 2, 5, and 7, and may further have a third intermediate layer 146b located between the third upper layer 146a and the third lower layer 146c, as shown in Figure 7. Since the second protrusion 145 and the third protrusion 146 are each composed of multiple layers, the visibility of the second protrusion 145 and the third protrusion 146 is easily improved, and high-precision alignment of the lens or mirror with respect to the second core 12 and the third core 13 can be made easier.

[0032] The first protrusion 144, the second protrusion 145, and the third protrusion 146 can be formed, for example, as the remaining portion when a part of the exit end side of the base 14 is removed by etching, blasting, or the like. Therefore, the material of the first protrusion 144, the second protrusion 145, and the third protrusion 146 may be the same as the material of the base 14. Also, the materials of the first protrusion 144, the second protrusion 145, and the third protrusion 146 may be the same as each other.

[0033] For example, if the base 14 has a cladding 17, at least a portion of the material of the first protrusion 144 may be the same as the material of the cladding 17. The portion of the first protrusion 144 whose material is the same as the cladding 17 can be formed by removing a portion of the cladding 17. Because at least a portion of the material of the first protrusion 144 is the same as the material of the cladding 17, even if the substrate 15 is prone to reflecting light, stray light is more easily scattered by the portion of the first protrusion 144 whose material is the same as the cladding 17. This can further improve the quality of the emitted light. Similarly, if the base 14 has a cladding 17, at least a portion of the second protrusion 145 and at least a portion of the third protrusion 146 may be the same as the material of the cladding 17.

[0034] In the embodiments shown in Figures 1 to 7, the portion of the first protrusion 144 whose material is the same as that of the cladding 17 is, for example, the first upper layer 144a. The portion of the second protrusion 145 whose material is the same as that of the cladding 17 is, for example, the second upper layer 145a. The portion of the third protrusion 146 whose material is the same as that of the cladding 17 is, for example, the third upper layer 146a. In addition, the entire material of each of the first protrusion 144, the second protrusion 145, and the third protrusion 146 may be the same as the material of the cladding 17.

[0035] Furthermore, for example, if the base 14 has a substrate 15, at least a portion of the material of the first protrusion 144 may be the same as the material of the substrate 15. A portion of the first protrusion 144 whose material is the same as that of the substrate 15 can be formed by removing a portion of the substrate 15. By removing a portion of the substrate 15 to form a portion of the first protrusion 144, the visibility of the first protrusion 144 tends to be improved. This can make high-precision alignment of lenses and mirrors easier. Similarly, if the base 14 has a substrate 15, at least a portion of the second protrusion 145 and at least a portion of the third protrusion 146 may be the same as the material of the substrate 15.

[0036] In the embodiments shown in Figures 1 to 7, the portion of the first protrusion 144 whose material is the same as that of the substrate 15 is, for example, the first lower layer 144c. The portion of the second protrusion 145 whose material is the same as that of the substrate 15 is, for example, the second lower layer 145c. The portion of the third protrusion 146 whose material is the same as that of the substrate 15 is, for example, the third lower layer 146c. In addition, the entire material of each of the first protrusion 144, the second protrusion 145, and the third protrusion 146 may be the same as the material of the substrate 15.

[0037] Furthermore, for example, if the base portion 14 has an insulating layer 16, at least a portion of the material of the first protrusion 144 may be the same as the material of the insulating layer 16. A portion of the first protrusion 144 whose material is the same as that of the insulating layer 16 can be formed by scraping off a portion of the insulating layer 16. Similarly, if the base portion 14 has an insulating layer 16, at least a portion of the second protrusion 145 and at least a portion of the third protrusion 146 may be the same as the material of the insulating layer 16.

[0038] In the embodiment shown in Figure 6, the portion of the first protrusion 144 whose material is the same as that of the insulating layer 16 is, for example, the first intermediate layer 144b. The portion of the second protrusion 145 whose material is the same as that of the insulating layer 16 is, for example, the second intermediate layer 145b. The portion of the third protrusion 146 whose material is the same as that of the insulating layer 16 is, for example, the third intermediate layer 146b. Note that in each of the first protrusion 144, the second protrusion 145, and the third protrusion 146, the entire material may be the same as that of the insulating layer 16.

[0039] As shown in Figures 1 to 7, the first protrusion 144 may be connected to the first side surface 141. This makes it less likely for unexpected reflections to occur when light leaks into the gap between the first protrusion 144 and the first side surface 141. This can further improve the quality of the emitted light. Also, if a portion of the material of the first protrusion 144 is the same as the material of the cladding 17, and the first protrusion 144 is connected to the first side surface 141, the cladding 17 will partially extend in the X direction from the first side surface 141. This increases the contact area between the cladding 17 and the component located beneath it (e.g., the substrate 15 or the insulating layer 16), which can improve the bonding strength. Similarly, the second protrusion 145 and the third protrusion 146 may be connected to the first side surface 141.

[0040] In a plan view, the first protrusion 144 may be connected to the second side surface 143. This may make it easier to precisely align the lens or mirror with respect to the first core 11. Similarly, the second protrusion 145 and the third protrusion 146 may be connected to the second side surface 143.

[0041] As shown in Figure 4, in a plan view, the entirety of the first protrusion 144 may be located between the first end face 111 and the second side surface 143. In this case, the width and position of the first protrusion 144 will be close to the width and position of the first end face 111. This may make it easier to precisely align the lens or mirror with respect to the first core 11. Similarly, the entirety of the second protrusion 145 and the entirety of the third protrusion 146 may be located between the first end face 111 and the second side surface 143.

[0042] As shown in Figures 1 and 4, the first core 11 may have a first linear portion 112 that extends in a first direction and connects to a first end face 111. This makes it easier to stabilize the beam shape and light intensity distribution of the light emitted from the first end face 111, thereby improving the quality of the emitted light. Similarly, the second core 12 may have a second linear portion 122 that extends in a first direction and connects to a second end face 121. The third core 13 may have a third linear portion 132 that extends in a first direction and connects to a third end face 131.

[0043] As shown in FIG. 4, the first convex portion 144 may be linear and extend in the first direction. This can make it easier to perform highly accurate alignment of the lens and the mirror with respect to the first core 11. Particularly when the first core 11 has the first straight portion 112, since the first convex portion 144 extends linearly in the first direction, the first convex portion 144 extends on the extension line of the first straight portion 112, so that highly accurate alignment of the lens and the mirror can be further facilitated. Similarly, the second core 12 and the third core 13 may be linear and extend in the first direction.

[0044] As shown in FIG. 4, in a plan view, the entire first convex portion 144 may be located within the range of the extension line of the first straight portion 112. When the entire first convex portion 144 is located within the range of the extension line of the first straight portion 112 in a plan view, the width and position of the first convex portion 144 are close to the width and position of the first end face 111. This can make it easier to perform highly accurate alignment of the lens and the mirror with respect to the first core 11. The range within the extension line of the first straight portion 112 means the region between two extension lines when both side surfaces along the first direction of the first straight portion 112 are virtually extended in the first direction in a plan view. Similarly, in a plan view, the entire second convex portion 145 may be located within the range of the extension line of the second straight portion 122. In a plan view, the entire third convex portion 146 may be located within the range of the extension line of the third straight portion 132.

[0045] As shown in FIG. 3, the distance d1 from the uppermost part of the first convex portion 144 to the lowermost part of the first end face 111 may be larger than the distance d2 from the first upper face 142 to the uppermost part of the first convex portion 144. Thereby, the light emitted from the first end face 111 is less likely to enter the first convex portion 144 immediately after being emitted from the first end face 111. As a result, the possibility that the efficiency of the light emitted from the first core 11 decreases, the first convex portion 144 interferes with the light emitted from the first core 11, or stray light further occurs can be reduced, and the quality of the light emitted from the first core 11 can be further improved. Similarly, the distance from the uppermost part of the second convex portion 145 to the lowermost part of the second end face 121 may be larger than the distance from the first upper face 142 to the uppermost part of the second convex portion 145. The distance from the uppermost part of the third convex portion 146 to the lowermost part of the third end face 131 may be larger than the distance from the first upper face 142 to the uppermost part of the third convex portion 146.

[0046] As shown in FIG. 2 and the like, the cladding 17 may have a first protruding portion 171 that protrudes above the first core 11, a second protruding portion 172 that protrudes above the second core 12, and a third protruding portion 173 that protrudes above the third core 13. Note that the cladding 17 does not necessarily have to have the above-described protruding portions, and the upper surface of the cladding 17 may be flat.

[0047] As shown in FIG. 4, in a plan view, the entire first convex portion 144 may be located within the range of the extension line of the first protruding portion 171. Thereby, highly accurate alignment of a lens or a mirror with respect to the first core 11 can be made easier. The range within the extension line of the first protruding portion 171 refers to the region between two extension lines when both side surfaces of the first protruding portion 171 along the first direction are virtually extended in the first direction in a plan view. Similarly, in a plan view, the entire second convex portion 145 may be located within the range of the extension line of the second protruding portion 172. In a plan view, the entire third convex portion 146 may be located within the range of the extension line of the third protruding portion 173.

[0048] As shown in Figure 4, in a plan view, the first side surface 141 may be parallel to the second side surface 143. This can make it easier to precisely align lenses and mirrors with respect to the first core 11. In particular, when the first straight section 112 of the first core 11 is perpendicular to the first side surface 141, the first direction (X direction), which is the direction of light emission, and the second side surface 143 are perpendicular, which can make it easier to precisely align lenses and mirrors with respect to the first core 11. In this disclosure, "parallel" allows for deviations in manufacturing accuracy, installation accuracy, etc. For example, even if the first side surface 141 and the second side surface 143 are tilted by about 2° in a plan view, they are still considered to be parallel.

[0049] In a plan view, the first side surface 141 does not have to be parallel to the second side surface 143. For example, if the first core 11 has a first linear portion 112 and the first linear portion 112 is inclined with respect to the first side surface 141, the first direction (X direction), which is the direction of light emission, is inclined with respect to the first side surface 141. In this case, by making the second side surface 143 perpendicular to the first direction (X direction), which is the direction of light emission, rather than parallel to the first side surface 141, it may be easier to precisely align lenses and mirrors with respect to the first core 11. The angle between the direction in which the first linear portion 112 extends and the first direction (X direction), which is the direction of light emission, may be changed according to the inclination angle between the first linear portion 112 and the first side surface 141 and the refractive index of the first core 11.

[0050] If the optical waveguide substrate 10 has a second core 12, the second end face 121 of the second core 12 does not necessarily have to be exposed to the first side surface 141. Similarly, if the optical waveguide substrate 10 has a third core 13, the third end face 131 of the third core 13 does not necessarily have to be exposed to the first side surface 141. The exit-side surface of the cladding 17 may be stepped, having a first side surface 141 where the first end face 111 is exposed, another side surface where the second end face 121 is exposed, and another side surface where the third end face 131 is exposed.

[0051] As shown in Figure 1, the cladding 17 may have recesses 174 for housing light-emitting elements that emit light incident on the first core 11. The incident end faces of each core may be exposed on the inner wall of the recess 174. The recess 174 opens upward (positive side in the Z direction) of the cladding 17. The recess 174 does not have to open downward (negative side in the Z direction) of the cladding 17, and may penetrate the cladding 17 in the Z direction. If the recess 174 penetrates the cladding 17 in the Z direction, the aforementioned insulating layer 16 that the optical waveguide substrate 10 may have may be exposed on the bottom surface of the recess 174. The shape of the recess 174 may be rectangular in plan view, or it may be any other shape. The optical waveguide substrate 10 having the recess 174 can be used as a package for housing light-emitting elements.

[0052] The optical waveguide substrate 10 may have a box-like structure surrounding the base portion 14. The box-like structure surrounds, for example, all sides of the base portion 14 except the top (positive side in the Z direction). The material of the box-like structure may be silicon, ceramic, resin, etc. The box-like structure may have windows located in the direction of emission of light from each core. The windows-like structures may be simply members that transmit light, or they may be members that can convert the emitted light into parallel light instead of lenses.

[0053] The first core 11, the second core 12, and the third core 13 each have multiple incident end faces but one exit end face, and may be combined wave paths with a confluence point in the middle of each optical path, or they may be independent non-combined wave paths without a confluence point in the middle of each optical path, as shown in Figure 1. Also, some cores may be combined wave paths and the remaining part may be non-combined wave paths. The shape of the cross-section of each core perpendicular to the direction in which each core extends may be rectangular, trapezoidal, or any other shape.

[0054] The heights of the first core 11, the second core 12, and the third core 13 may all be uniform and identical. This facilitates adjustment of the cross-sectional area of ​​each core. The heights of the first core 11, the second core 12, and the third core 13 may be, for example, 2 to 10 μm. The heights of the first protrusion 144, the second protrusion 145, and the third protrusion 146 may be, for example, 2 to 10 μm, which is about the same as the thickness of each core. The heights of the first projection 171, the second projection 172, and the third projection 173 may be, for example, 2 to 10 μm, which is about the same as the thickness of each core. In this disclosure, "height" refers to the dimension in the Z direction.

[0055] [Light-emitting device] As shown in Figure 8, the light-emitting device 20 may include an optical waveguide substrate 10, a first light-emitting element 21 that emits light incident on the first core 11, and a cover 25. The light-emitting device 20 may further include a second light-emitting element 22 that emits light incident on the second core 12, a third light-emitting element 23 that emits light incident on the third core 13, a plurality of electrodes 24, and a lens 26.

[0056] The first light-emitting element 21, the second light-emitting element 22, and the third light-emitting element 23 may be, for example, laser diodes (LDs). Each light-emitting element emits light at a predetermined wavelength, and light can be incident on the incident end face of each core. As shown in Figure 8, if the cladding 17 of the optical waveguide substrate 10 has a recess 174, the first light-emitting element 21, the second light-emitting element 22, and the third light-emitting element 23 may be housed in the recess 174.

[0057] Multiple electrodes 24 can be connected to the first light-emitting element 21, the second light-emitting element 22, and the third light-emitting element 23. If the cladding 17 has recesses 174, the electrodes 24 may extend from the inside to the outside of the recesses 174, as shown in Figure 8. The material of the electrodes 24 may be Ti, Pt, Au, Al, etc. Each light-emitting element and each electrode 24 can be electrically connected by, for example, a brazing material, a conductive adhesive, a bonding wire, etc.

[0058] The cover 25 may be positioned above each light-emitting element. As shown in Figure 8, if the cladding 17 has recesses 174, the cover 25 may be positioned on the cladding 17, covering each light-emitting element so as to seal the inside of the recesses 174. If the optical waveguide substrate 10 has a box-shaped structure surrounding the base 14, the cover 25 may be positioned on the box-shaped structure, covering each light-emitting element.

[0059] The lid 25 may be flat or concave, opening to the bottom surface (the lower surface in the Z direction) as shown in Figure 8. The lid 25 may have minute notches corresponding to the first protrusion 171, second protrusion 172, and third protrusion 173 of the cladding 17.

[0060] The material of the lid 25 may be, for example, glass, silicon, or metal. Examples of glass include quartz, borosilicate, and sapphire. Examples of metals include aluminum, copper, iron, and alloys such as Fe-Ni-Co. If the material of the lid 25 is metal, the lid 25 may have a plating layer on its surface. Examples of materials for the plating layer include gold and nickel.

[0061] An annular conductor may be positioned between the cover 25 and the optical waveguide substrate 10. By joining the cover 25 and the optical waveguide substrate 10 with the conductor in between, the airtightness is improved compared to when they are directly joined with a resin-based adhesive.

[0062] As shown in Figure 8, the lens 26 may be positioned in the direction of emission of light from the optical waveguide substrate 10. The lens 26 may be, for example, a convex lens, a diffracting lens, a rod lens, a ball lens, etc. The lens 26 may also be a component that has the function of converting the light emitted from the optical waveguide substrate 10 into parallel light.

[0063] [Electronic Device] The electronic device 30 may include a light-emitting device 20 and a display unit 31 that displays information using light emitted from the light-emitting device 20. The electronic device 30 may be, for example, AR glasses, a head-up display, a projector, etc.

[0064] For example, if the electronic device 30 is AR glasses, as shown in Figure 9, the electronic device 30 may further include temples 32 and a control unit 33. In this case, the light-emitting device 20 may be located inside the temples 32. The temples 32 may be bendable or not. If they are bendable, the light-emitting device 20 does not need to emit light when bent.

[0065] The display unit 31 may include a scanning mirror 311 and a light guide unit 312. The scanning mirror 311 is, for example, a MEMS (Micro-Electro Mechanical Systems) mirror and scans the light emitted from the light-emitting device 20. The scanned light is input to a light guide plate, half mirror, etc., of the light guide unit 312. The scanning mirror 311 may be located inside the arbor 32.

[0066] The light guide unit 312 may have a light guide plate or a half mirror as described above, and may be capable of projecting incident light onto the user's eyeball. The light guide unit 312 may also be light-transmitting. For example, the light guide unit 312 may be configured to be a waveguide type, a half mirror type, etc., so that the projected image can be seen by overlapping it with the actual image transmitted through the display unit 31. If the light guide unit 312 is a half mirror type, the light guide unit 312 may be separated from the glass surface. The light guide unit 312 may be transparent or it may be colored to block a portion of the transmitted light.

[0067] The projected image data is not particularly limited, but may be received from an external source via wireless communication or the like, or it may be generated by the control unit 33 based on measurement results from sensors equipped in the AR glasses. Furthermore, the image data received from an external source and the image data generated by the control unit 33 may be used in combination.

[0068] The control unit 33 includes, for example, a CPU, RAM, non-volatile memory, etc., and performs control processing related to image display. In addition to the above, the control unit 33 may also include an LD driver for controlling the LD, a MEMS driver for scanning and controlling the MEMS mirror, etc. The control unit 33 may be located inside or on the side of the lanyard 32, or it may be located outside the lanyard 32 via a cable.

[0069] The glass surface including the light guide 312 may be separate on the left and right sides, as shown in Figure 9, or it may be a single surface. The glass surface may have a large curved surface, especially in the case of a half-mirror system.

[0070] The AR glasses electronic device 30 may also be a head-mounted display having a band, support, etc. for being attached to a person's head instead of the temples 32.

[0071] The electronic device 30 may also include a communication unit, a battery, etc. If the electronic device 30 is AR glasses, the communication unit, battery, etc. may be located inside or on the side of the temple 32, or they may be located outside the temple 32 via a cable.

[0072] The following are further examples of embodiments of the optical waveguide substrate, light-emitting device, and electronic device relating to this disclosure.

[0073] (1) One embodiment of an optical waveguide substrate according to the present disclosure comprises a first core and a base. The first core has a first end face from which light can be emitted in a first direction. The base houses the first core. The base has a first side surface, a first upper surface, a second side surface, and a first protrusion. The first side surface exposes the first end face. The first upper surface is connected to the first side surface. The second side surface is connected to the first upper surface and is located below the first upper surface. The first protrusion is located on the first upper surface. The first protrusion is located below the first end face. At least a portion of the first protrusion is located between the first end face and the second side surface in a plan view.

[0074] (2) One embodiment of the optical waveguide substrate according to the present disclosure is the optical waveguide substrate of (1) above, wherein the base comprises a substrate and a cladding. The substrate has a second side surface. The cladding is located on the substrate. At least a portion of the material of the first protrusion is the same as the material of the cladding.

[0075] (3) One embodiment of the optical waveguide substrate according to the present disclosure is the optical waveguide substrate described in (2) above, wherein at least a portion of the material of the first protrusion is the same as the material of the substrate.

[0076] (4) One embodiment of the optical waveguide substrate according to the present disclosure is an optical waveguide substrate according to any of (1) to (3) above, wherein the first protrusion is connected to the first side surface.

[0077] (5) One embodiment of the optical waveguide substrate according to the present disclosure is an optical waveguide substrate according to any of (1) to (4) above, wherein in a plan view, the entirety of the first protrusion is located between the first end face and the second side surface.

[0078] (6) One embodiment of the optical waveguide substrate according to the present disclosure is an optical waveguide substrate according to any of (1) to (5) above, wherein in a plan view, the first protrusion is connected to the second side surface.

[0079] (7) One embodiment of the optical waveguide substrate according to the present disclosure is an optical waveguide substrate according to any of (1) to (6) above, wherein the first core has a first straight portion that extends in the first direction and connects to the first end face.

[0080] (8) One embodiment of the optical waveguide substrate according to the present disclosure is an optical waveguide substrate according to any of (1) to (7) above, wherein the first protrusion is linear and extends in the first direction.

[0081] (9) One embodiment of the optical waveguide substrate according to the present disclosure is an optical waveguide substrate according to any of (1) to (8) above, wherein in a plan view, the entirety of the first protrusion is located within the range of the extension of the first straight portion.

[0082] (10) One embodiment of the optical waveguide substrate according to the present disclosure is an optical waveguide substrate according to any of (1) to (9) above, wherein the distance from the top of the first protrusion to the bottom of the first end face is greater than the distance from the first top surface to the top of the first protrusion.

[0083] (11) One embodiment of an optical waveguide substrate according to the present disclosure is an optical waveguide substrate according to any of (1) to (10) above, wherein the base comprises a substrate and a cladding. The substrate has the second side surface. The cladding is located on the substrate. The cladding has a first projection that protrudes above the first core, and in a plan view, the entirety of the first projection is located within the range of the extension of the first projection.

[0084] (12) One embodiment of an optical waveguide substrate according to the present disclosure is an optical waveguide substrate according to any of (1) to (11) above, comprising a second core having a second end face capable of emitting light in the first direction, located inside the base. The base has a second protrusion located on the first upper surface. The second protrusion is located below the second end face. At least a portion of the second protrusion is located between the second end face and the second side surface in a plan view. The width of the second end face is narrower than the width of the first end face. The width of the second protrusion is narrower than the width of the first protrusion.

[0085] (13) One embodiment of an optical waveguide substrate according to the present disclosure is an optical waveguide substrate according to any of (1) to (12) above, wherein the base comprises a substrate and a cladding. The substrate has a second side surface. The cladding is located on the substrate. The cladding has recesses for housing light-emitting elements that emit light incident on the first core.

[0086] (14) One embodiment of the light-emitting device according to the present disclosure comprises the optical waveguide substrate described in (13) above, a first light-emitting element housed in the recess and emitting light incident on the first core, and a cover that covers the recess.

[0087] (15) One embodiment of the electronic device relating to the present disclosure comprises the light-emitting device described in (14) above, and a display unit that displays information using light emitted from the light-emitting device.

[0088] Furthermore, details shown in the embodiments described above may be modified as appropriate without departing from the spirit of this disclosure. The scope of this disclosure includes the scope of the invention as described in the claims and its equivalents. Various combinations of each embodiment are not limited to the examples of embodiments described above. Combinations of each embodiment are also possible.

[0089] 10 Optical waveguide substrate 11 First core 111 First end face 112 First straight section 12 Second core 121 Second end face 122 Second straight section 13 Third core 131 Third end face 132 Third straight section 14 Base 141 First side surface 142 First top surface 143 Second side surface 144 First protrusion 144a First upper layer 144b First middle layer 144c First lower layer 145 Second protrusion 145a Second upper layer 145b Second middle layer 145c Second lower layer 146 Third protrusion 146a Third upper layer 146b Third middle layer 146c Third lower layer 15 Substrate 16 Insulating layer 17 Cladding 171 First projection 172 Second projection 173 Third protrusion 174 Recess 20 Light-emitting device 21 First light-emitting element 22 Second light-emitting element 23 Third light-emitting element 24 Electrode 25 Cover 26 Lens 30 Electronic device 31 Display unit 311 Scanning mirror 312 Light guide unit 32 Handle 33 Control unit

Claims

1. An optical waveguide substrate comprising: a first core having a first end face capable of emitting light in a first direction; and a base in which the first core is located, wherein the base has a first side surface on which the first end face is exposed; a first upper surface connected to the first side surface; a second side surface connected to the first upper surface and located below the first upper surface; and a first protrusion located on the first upper surface, wherein the first protrusion is located below the first end face, and at least a portion of the first protrusion is located between the first end face and the second side surface in a plan view.

2. The optical waveguide substrate according to claim 1, wherein the base comprises a substrate having the second side surface and a cladding located on the substrate, and at least a portion of the material of the first protrusion is the same as the material of the cladding.

3. The optical waveguide substrate according to claim 2, wherein at least a portion of the material of the first protrusion is the same as the material of the substrate.

4. The optical waveguide substrate according to any one of claims 1 to 3, wherein the first protrusion is connected to the first side surface.

5. In a plan view, the entirety of the first protrusion is located between the first end face and the second side surface, as described in any one of claims 1 to 4.

6. In a plan view, the first protrusion is connected to the second side surface, as described in any one of claims 1 to 5.

7. The optical waveguide substrate according to any one of claims 1 to 6, wherein the first core has a first linear portion extending in the first direction and connected to the first end face.

8. The optical waveguide substrate according to any one of claims 1 to 7, wherein the first protrusion is linear and extends in the first direction.

9. In a plan view, the entirety of the first protrusion is located within the range of the extension of the first straight section, as described in any one of claims 1 to 8.

10. The optical waveguide substrate according to any one of claims 1 to 9, wherein the distance from the top of the first protrusion to the bottom of the first end face is greater than the distance from the first upper surface to the top of the first protrusion.

11. The optical waveguide substrate according to any one of claims 1 to 10, wherein the base comprises a substrate having the second side surface and a cladding located on the substrate, the cladding having a first projection projecting above the first core, and in a plan view, the entirety of the first projection is located within the range of the extension of the first projection.

12. An optical waveguide substrate according to any one of claims 1 to 11, comprising a second core having a second end face capable of emitting light in the first direction, wherein the base has a second protrusion located on the first upper surface, the second protrusion is located below the second end face, at least a portion of the second protrusion is located between the second end face and the second side surface in a plan view, the width of the second end face is narrower than the width of the first end face, and the width of the second protrusion is narrower than the width of the first protrusion.

13. The optical waveguide substrate according to any one of claims 1 to 12, wherein the base comprises a substrate having the second side surface and a cladding located on the substrate, and the cladding has recesses for housing light-emitting elements that emit light incident on the first core.

14. A light-emitting device comprising: an optical waveguide substrate according to claim 13; a first light-emitting element housed in the recess and emitting light incident on the first core; and a cover covering the recess.

15. An electronic device comprising: a light-emitting device according to claim 14; and a display unit that displays information using light emitted from the light-emitting device.

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