Optical waveguide package

Abstract

This optical waveguide package is provided with: a substrate (9) having a first surface (8); a cladding layer (12), which is positioned on the first surface, has a second surface (10) that faces the first surface, and a third surface (11) that is positioned on the opposite side of the second surface, and which has an element mounting region (3) that opens on the third surface; a core (5) that is positioned within the cladding and has an incident surface (13) facing the element mounting region and an exit surface (15) exposed from an end surface of the cladding; and a side wall (16a) surrounding the element mounting region on the substrate. The side wall is formed of a plurality of materials having elastic coefficients different from each other.

Description

Technical Field

[0001] The present disclosure relates to optical waveguide packages. Background Art

[0002] Prior art literature

[0003] Patent Literature

[0004] Patent Document 1: Japanese Patent Application Laid-Open No. 10-054917

[0005] Patent document 2: Japanese Patent Application Publication No. 2007-328201. Summary of the invention

[0006] The optical waveguide package disclosed in the present invention comprises: a substrate having a first surface; a cladding located on the first surface and having a second surface opposite to the first surface and a third surface located on the opposite side of the second surface, the cladding having a component mounting area opened on the third surface; a core located in the cladding and having an incident surface facing the component mounting area and an exit surface exposed from the end face of the cladding; and a side wall at least partially surrounding the component mounting area on the substrate; the side wall is composed of a plurality of materials with different elastic coefficients. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] The objects, features, and advantages of the present disclosure will become more apparent from the following detailed description and the accompanying drawings.

[0008] Figure 1 This is an exploded perspective view showing a light emitting device including an optical waveguide package according to an embodiment of the present disclosure.

[0009] Figure 2 yes Figure 1 A top view of the light emitting device is shown.

[0010] Figure 3A It is along Figure 2 Cross-sectional view when observing along the cutting line IIIA-IIIA.

[0011] Figure 3B It is along Figure 2 Cross-sectional view when observing along the cutting line IIIB-IIIB.

[0012] Figure 4 Yes means Figure 1 A perspective view of a portion of an optical waveguide layer of an optical waveguide package is shown.

[0013] Figure 5 FIG. 1 is a plan view showing a light emitting device according to another embodiment of the present disclosure.

[0014] Figure 6It is a top view showing a light emitting device according to still another embodiment of the present disclosure.

[0015] Figure 7 It is a top view showing a light emitting device according to still another embodiment of the present disclosure.

[0016] Figure 8 It is a top view showing a light emitting device according to still another embodiment of the present disclosure.

[0017] Fig. 9 It is along Figure 8 Cross-sectional view when observing along the cutting line IX-IX.

[0018] Fig.10 It is a top view showing a light emitting device according to still another embodiment of the present disclosure. DETAILED DESCRIPTION

[0019] A conventional optical waveguide package is described in, for example, Patent Document 1. Patent Document 1 discloses a structure in which an optical waveguide is formed on a substrate, a groove is provided in a direction crossing the optical waveguide, and a light-shielding film is provided on the inner wall of the groove to prevent a radiation mode generated in the optical waveguide element from leaking into an optical fiber opposed to a light-emitting element in a cladding mode.

[0020] Another conventional optical waveguide package is described in, for example, Patent Document 2. Patent Document 2 discloses a structure in which a gap where one end of a core and an optical element are located is bonded to a lid to be hermetically sealed to obtain gas barrier properties.

[0021] In the prior art of the above-mentioned Patent Documents 1 and 2, since a cover is bonded to the element mounting region, the mounting region is deformed due to stress when the cover is bonded, resulting in a decrease in the optical coupling efficiency between the light emitting element and the waveguide. Therefore, an optical waveguide package is required that can reduce the decrease in the optical coupling efficiency between the light emitting element and the waveguide.

[0022] Figure 1 This is an exploded perspective view showing a light emitting device including an optical waveguide package according to an embodiment of the present disclosure. Figure 2 yes Figure 1 A top view of the light emitting device shown, Figure 3A It is along Figure 2 The cross-sectional view when observing the section line IIIA-IIIA, Figure 3B It is along Figure 2 In the following embodiments, the material constituting the side wall is described as a material having different elastic moduli and light refractive indices.

[0023] The optical waveguide package 2 of the present embodiment comprises: a substrate 9 having a first surface 8; a cladding 12 located on the first surface 8 and having a second surface 10 opposite to the first surface 8 and a third surface 11 located on the opposite side of the second surface 10, the cladding 12 having a component mounting region 3 opened on the third surface 11; a core 5 located in the cladding 12 and having an incident surface 13 facing the component mounting region 3 and an exit surface 15 exposed from an end surface 14 of the cladding 12; and a side wall 16a at least partially surrounding the component mounting region 3 on the substrate 9 and composed of a plurality of materials M1 and M2 having different elastic coefficients. The core 5 and the cladding 12 constitute an optical waveguide layer 19. The substrate 9 is composed of a rectangular plate-like body when viewed from above.

[0024] The light emitting device 1 includes: the aforementioned optical waveguide package 2, the light emitting element 4 located in the element mounting area 3, the lens 6 located on the optical path of the light emitted from the core 5, and, for example, a box-shaped cover 7 with one side open, which covers the element mounting area 3. The cover 7 is not limited to a box shape, and may be, for example, a plate shape, or may be in a different shape as appropriate.

[0025] Figure 4 Yes means Figure 1 3D view of a portion of the optical waveguide layer of the optical waveguide package shown in FIG. The optical waveguide layer 19 can be, for example, glass such as quartz, resin, etc. As the material constituting the optical waveguide layer 19, both can be glass or resin, and the core 5 and the cladding 12 can also be glass on one side and resin on the other side. The refractive index of the core 5 and the cladding 12 are different, and the refractive index of the core 5 is higher than the refractive index of the cladding 12. By utilizing this difference in refractive index, light is totally reflected at the interface between the core 5 and the cladding 12. That is, if the optical waveguide is made of a material with a high refractive index and surrounded by a material with a low refractive index, the light can be confined in the core 5 with a high refractive index.

[0026] The light emitting device 1 further comprises: a first electrode 20, which is located in the element mounting region 3 and carries the light emitting element 4; and a second electrode 21, which is connected to the first electrode 20 and extends from the element mounting region 3 to the outside. The lens 6 is located on the optical path of the light emitted from the core 5, and can collimate or focus the light emitted from the core 5. The lens 6 can be, for example, a plano-convex lens whose incident surface is a flat surface and whose exit surface is a convex surface.

[0027] The substrate 9 may be, for example, an organic wiring substrate in which a dielectric layer is formed of an organic material. The organic wiring substrate may be, for example, a printed wiring substrate, a build-up wiring substrate, a flexible wiring substrate, etc. Examples of organic materials used in the organic wiring substrate include epoxy resins, polyimide resins, polyester resins, acrylic resins, phenolic resins, and fluororesins.

[0028] The substrate 9 may be a ceramic wiring substrate in which the dielectric layer is composed of a ceramic material. Examples of ceramic materials used in the ceramic wiring substrate include alumina sintered bodies, mullite sintered bodies, silicon carbide sintered bodies, aluminum nitride sintered bodies, and glass ceramic sintered bodies. In addition, the material of the substrate 9 may be silicon, silicon dioxide, or silicon oxynitride (SiON) called silicon oxynitride.

[0029] The light emitting element 4 includes a light emitting element 4R that emits red light R, a light emitting element 4G that emits green light G, and a light emitting element 4B that emits blue light B. These light emitting elements 4R, 4G, 4B may be, for example, light emitting diodes (LEDs) or laser diodes (LDs). Each of the light emitting elements 4R, 4G, 4B is configured so that the emission ends of the respective color lights are opposite to the incident surfaces 13R, 13G, 13B of the core 5 that are exposed toward the element mounting area 3. The core 5 may also have: a plurality of split paths 41R, 41G, 41B having incident surfaces 13R, 13G, 13B; a combining section 17 where the plurality of split paths 41R, 41G, 41B meet; and a converging path 18 extending between the combining section 17 and the emission surface 15. The light emitting elements 4R, 4G, 4B are positioned in the element mounting region 3 so that the optical axes of the light emitting elements 4R, 4G, 4B coincide with the centers of the incident end faces 4a, 4b, 4c of the optical axis division paths 41a, 41b, 41c.

[0030] The element mounting region 3 may be a recess or a through hole opened on the third surface 11 of the cladding 12. In the present embodiment, the element mounting region 3 is a through hole penetrating from the third surface 11 of the cladding 12 to the second surface 10. In a plan view, on the third surface 11 of the cladding 12, the bonding material 22 is arranged in an annular shape so as to surround the opening of the element mounting region 3, and the cover 7 is bonded to the third surface 11 of the cladding 12 by the bonding material 22. The inside of the element mounting region 3 is hermetically sealed by the cover 7 to protect the light emitting element 4.

[0031] The cover 7 is made of a glass material such as quartz, borosilicate, sapphire, etc. The bonding material can be any material that can bond the cladding 12 to the cover 7 and make the two hermetically sealed, for example, Au-Sn-based, Sn-Ag-Cu-based solder, metal nanoparticle paste such as Ag or Cu, or glass paste, etc. can be used.

[0032] The core 5 of the present embodiment is made of silicon oxynitride (SiON) which is called silicon oxynitride, and the cladding 12 may be made of silicon oxide (SiO 2 ).

[0033] A plurality of materials M1, M2, ..., M having different elastic moduli from each otherm-1 、M m (m is a positive integer) includes a material having a refractive index difference Δn2 (=Δn1) which is the same as the refractive index difference Δn1 (=n11-n12) between the core 5 (refractive index n11) and the cladding 12 (refractive index n12). A plurality of materials M1, M2, ..., M1 having different elastic coefficients E from each other m-1 、M m The first refractive index material M1 having a first refractive index n1 and the second refractive index material M2 having a second refractive index n2 lower than the first refractive index n1 are included.

[0034] When the elastic coefficient of the core 5 is larger than that of the cladding 12, the shape-retaining force of the core 5 is more dominant than the shape-restoring force of the cladding 12 that is deformed due to the pressing force on the remaining structures other than the cover 7 due to the joining of the cover 7, etc., so that the deformation of the core 5 from the designed shape can be reduced and the specified shape can be reliably achieved. In addition, when the elastic coefficient of the core 5 is smaller than the elastic coefficient of the cladding 12, the deformation of the cladding 12 caused by the action of external force is small, and thus the deformation transmitted from the cladding 12 to the core 5 is also small. Since the deformation of the core 5 is small, the reduction in light transmission efficiency can be reduced. In this way, by forming the side wall 16a with a plurality of materials M1 and M2 having different elastic coefficients, it is possible to improve the resistance to stress caused by, for example, thermal deformation.

[0035] By using a plurality of materials with different elastic coefficients for a material having a refractive index difference Δn2 that is the same as the refractive index difference Δn1 between the core 5 and the cladding 12, it is possible to emit unnecessary light such as reflected light within the component mounting area 3 from the component mounting area 3 to the outside, thereby preventing unnecessary light from being incident on the core 5.

[0036] The first refractive index material M1 is located in the same height range as the incident surface 13 of the core 5 in the direction perpendicular to the first surface 8. That is, the first refractive index material M1 is located at the center of the side wall 16a behind the element mounting region 3. As a result, unnecessary light emitted slightly from the light emitting element 4 in the direction opposite to the incident surface of the core 5 is emitted from the element mounting region 3 to the outside through the first refractive index material M1, and thus, it is possible to prevent the unnecessary light from being reflected on the inner surface of the side wall 16a and the like and from being incident on the core 5 from the incident surface 13. In this case, since such unnecessary light is emitted from the element mounting region 3 to the outside, the first refractive index material M1 may be arranged to reach the outer surface from the inner surface of the side wall 16a.

[0037] The side wall 16a is made of a plurality of materials having different elastic coefficients. Therefore, even if a pressing force is applied to the side wall 16a from the cover 7 when the cover 7 is bonded to the side wall 16a, the pressing force is dispersed along the material with a high elastic coefficient to the entire side wall 16a, and the pressing force from the dispersed material with a high elastic coefficient is absorbed by the material with a low elastic coefficient, thereby reducing the deformation of the portion defining the element mounting region 3. Thus, the deformation of the substrate 9 can be reduced, the displacement of each light emitting element 4R, 4G, 4B relative to the incident surface 13R, 13G, 13B can be reduced, the reduction in the amount of light incident from each light emitting element 4R, 4G, 4B to each incident surface 13R, 13G, 13B can be reduced, and the reduction in light propagation efficiency can be reduced.

[0038] In addition, by forming at least one of the materials constituting the side wall 16 a having elastic moduli different from each other using the same material as the core 5 and the cladding 12 , the side wall 16 a can be easily manufactured.

[0039] Since the side wall 16a is a structure that partially surrounds the element mounting area 3 and is C-shaped at least in a plan view, the side wall 16a can be formed to avoid the area where the division paths 41R, 41G, and 41B of the core 5 are arranged. Therefore, both ends of the side wall 16a in the circumferential direction are located on the end surface 14 side of the incident surface 13 of the core 5, and it is possible to prevent the unnecessary light in the first refractive index material M1 that has passed through the side wall 16a from being mixed into the core 5 from the incident surface 13 of the core 5. In addition, when forming the side wall 16a, it is sufficient to reduce the influence of the pressure on the division paths 41R, 41G, and 41B, so that the side wall 16a can be easily formed. In addition, since the first refractive index material M1 is separated from the core 5, it is possible to prevent the unnecessary light that has passed through the first refractive index material M1 from being mixed into the core 5 not only from the incident surface 13 but also from the side.

[0040] Figure 5 1 is a top view of a light emitting device according to another embodiment of the present disclosure. In addition, the same reference numerals are given to the parts corresponding to the above-mentioned embodiments. The side wall 16b of the optical waveguide package 2b of the present embodiment is formed into a closed loop shape when viewed from above, and the side wall 16b is provided around the entire circumference of the element mounting area 3. The material of the side wall 16b is the same as that of the above-mentioned side wall 16a. With such a structure, the side wall 16b is also sandwiched between the respective division paths 41R, 41G, 41B of the core 5, and the pressing force when the cover 7 is joined, etc., on the respective division paths 41R, 41G, 41B can be alleviated.

[0041] Figure 61 is a top view of a light emitting device according to another embodiment of the present disclosure. In addition, the same reference numerals are given to portions corresponding to the aforementioned embodiments. The optical waveguide package 2c of the present embodiment is roughly formed into a closed loop when viewed from above, and is formed by separating a plurality of intervals ΔL in the direction in which the side wall 16c extends in the regions on both sides of the short side direction parallel to the direction in which the light emitting elements 4R, 4G, and 4B are arranged and in a region on the side opposite to the incident surfaces 13R, 13G, and 13B in the long side direction. With such a structure, even if the side wall 16c is thermally expanded due to the heat from the light emitting elements 4R, 4G, and 4B, the deformation caused by the thermal expansion can be absorbed by each interval ΔL, thereby reducing the deformation of the substrate 9 caused by the thermal expansion and reducing the reduction in the optical coupling efficiency to the core 5.

[0042] Figure 7 : is a top view of a light emitting device according to another embodiment of the present disclosure. In addition, the same figure marks are given to the parts corresponding to the aforementioned embodiments. The optical waveguide package 2d of the present embodiment has a side wall 16c that is roughly formed into a closed loop when viewed from above. The side wall 16c has a plurality of gaps 30 formed parallel to the long side direction in the areas on both sides of the short side direction parallel to the direction in which the light emitting elements 4R, 4G, and 4B are arranged and in an area on the side of the long side direction opposite to the incident surface 13R, 13G, and 13B. With such a structure, even if the side wall 16c is thermally expanded due to the heat from the light emitting elements 4R, 4G, and 4B, the deformation caused by the thermal expansion can be absorbed by each gap 30. Therefore, the deformation of the substrate 9 caused by the thermal expansion can be reduced, and the reduction in the optical coupling efficiency to the core 5 can be reduced.

[0043] Figure 8 is a top view showing a light emitting device according to another embodiment of the present disclosure, Fig. 9 It is along Figure 8 A cross-sectional view when observed along the cutting line IX-IX. In addition, the same figure marks are marked on the parts corresponding to the aforementioned embodiments. The optical waveguide package 2e of this embodiment has a side wall 16e formed in a closed loop when viewed from above. The side wall 16e is configured to surround the opening of the component mounting area 3 on the third surface 11 of the cladding 12. The thickness T of the side wall 16e is set to be greater than 0.1μm and less than 10μm, for example. The side wall 16e can also be bonded to the third surface 11 using a bonding material, for example. As the bonding material, for example, Au-Sn-based, Sn-Ag-Cu-based solder, metal nanoparticle paste such as Ag or Cu, or glass paste can be used. Through such a structure, it is possible to provide an optical waveguide package with excellent optical coupling efficiency and a light-emitting device using the optical waveguide package without significantly changing the structure of the existing optical waveguide package.

[0044] Fig.101 is a top view of a light emitting device according to another embodiment of the present disclosure. In addition, the same reference numerals are given to the parts corresponding to the above-mentioned embodiments, and repeated descriptions are omitted. In the present embodiment, the core 5 may also be composed of three independent cores 5R, 5G, and 5B. As in the above-mentioned embodiment, the incident surfaces 13R, 13G, and 13B of the three cores 5R, 5G, and 5B are arranged at positions corresponding to the light emitting elements 4R, 4G, and 4B in a manner that the centers of the three incident surfaces 13R, 13G, and 13B are consistent with the optical axes of the light emitting elements 4R, 4G, and 4B, and are separated from each other. The exit surfaces 15R, 15G, and 15B of the three cores 5R, 5G, and 5B are arranged close to each other, and the exit lights from the exit surfaces 15R, 15G, and 15B of the cores 5R, 5G, and 5B may also be emitted in parallel through a lens 6, for example. Between the incident surfaces 13R, 13G, 13B and the exit surfaces 15R, 15G, 15B, the three cores 5R, 5G, 5B may also be brought together in a close manner and extend in parallel to the exit surfaces 15R, 15G, 15B. In this case, an image formed by the exit lights from the three exit surfaces 15R, 15G, 15B may also be synthesized by an external device, for example.

[0045] In another embodiment, the light emitting element 4 is not limited to a light emitting diode, and may be, for example, an LD (Laser Diode), a VCSEL (Vertical Cavity Surface Emitting Laser), or the like.

[0046] In the above-mentioned embodiments, as the materials constituting the side walls 16a to 16e, the case where two materials, a first refractive index material M1 and a second refractive index material M2, which have different elastic coefficients, are used is described. However, in other embodiments of the present disclosure, three or more materials, M1, M2, ..., M3, M4, M5, M6, M7, M8, M9, M10, M11, M12, M13, M14, M15, M16, M17, M18, M19, M20, M21, M22, M33, M19, M23, M24, M35, M19, M25, M26, M36, M47, M58, M27, M28, M29, M37, M38, M49, M59, M60, M70, M80, M9, M10, M11, M12 m-1 、M m (m is a positive integer) to form a side wall.

[0047] According to the optical waveguide package of the present disclosure, it is possible to provide an optical waveguide package that reduces the decrease in optical coupling efficiency between a light emitting element and a waveguide.

[0048] The present disclosure can be implemented in the following configurations (1) to (6).

[0049] (1) An optical waveguide package, wherein:

[0050] have:

[0051] A substrate having a first surface;

[0052] a cladding layer located on the first surface and having a second surface opposite to the first surface and a third surface located on the opposite side of the second surface, the cladding layer having a component mounting region opened on the third surface;

[0053] a core located in the cladding and having an incident surface facing the element mounting region and an exit surface exposed from an end surface of the cladding; and

[0054] A side wall surrounding the component mounting area on the substrate;

[0055] The side wall is formed of a plurality of materials having different elastic coefficients from each other.

[0056] (2) The optical waveguide package according to (1) above, wherein:

[0057] At least one of the plurality of materials of the side wall includes a portion that is C-shaped in a plan view.

[0058] (3) The optical waveguide package according to (1) or (2) above, wherein:

[0059] The plurality of materials having different elastic moduli include a material having the same refractive index difference as that between the core and the cladding,

[0060] The plurality of materials having different elastic coefficients include: a first refractive index material having a first refractive index, and a second refractive index material having a second refractive index lower than the first refractive index.

[0061] The first refractive index material is located in the same height range as the incident surface of the core in a direction perpendicular to the first surface.

[0062] (4) The optical waveguide package according to (3) above, wherein:

[0063] The first refractive index material is configured to be separated from the core.

[0064] (5) The optical waveguide package according to any one of (1) to (4) above, wherein:

[0065] The side wall includes: a first material which is the same material as the core, and a second material which is the same material as the cladding and is arranged in a manner of sandwiching the first material.

[0066] The first material has a higher modulus of elasticity than the second material.

[0067] (6) The optical waveguide package according to any one of (1) to (4) above, wherein:

[0068] The side wall includes: a first material which is the same material as the core, and a second material which is the same material as the cladding and is arranged in a manner of sandwiching the first material.

[0069] The first material has a lower modulus of elasticity than the second material.

[0070] The embodiments of the present disclosure are described in detail above. In addition, the present disclosure is not limited to the above embodiments, and various changes and improvements can be made without departing from the scope of the present disclosure. Of course, all or part of the above embodiments can be combined within the scope of appropriate non-contradiction.

[0071] Description of Reference Numerals

[0072] 1 Lighting device

[0073] 2 Optical waveguide package

[0074] 3 Component mounting area

[0075] 4, 4R, 4G, 4B light emitting elements

[0076] 5. 5R, 5G, 5B fiber core

[0077] 6 lenses

[0078] 8 Side 1

[0079] 9 substrates

[0080] 10 Side 2

[0081] 11 Side 3

[0082] 12 layers

[0083] 13, 13R, 13G, 13B incident surface

[0084] 14 End face

[0085] 15 exit surface

[0086] 16a~16e side wall

[0087] 17 Combined Wave Department

[0088] 18 Huiju Road

[0089] 19 Optical waveguide layer

[0090] 20 first electrode

[0091] 21 Second electrode

[0092] 41R, 41G, 41B split road

[0093] M1 first refractive index material

[0094] M2 second refractive index material

Claims

1. An optical waveguide package, wherein: have: A substrate having a first surface; a cladding layer located on the first surface and having a second surface opposite to the first surface and a third surface located on the opposite side of the second surface, the cladding layer having a component mounting region opened on the third surface; a core located in the cladding and having an incident surface facing the element mounting area and an exit surface exposed from an end surface of the cladding; as well as A side wall at least partially surrounding the component mounting area on the substrate; The side wall is formed of a plurality of materials having different elastic coefficients from each other.

2. The optical waveguide package according to claim 1, wherein: At least one of the plurality of materials of the side wall includes a portion that is C-shaped in a plan view.

3. The optical waveguide package according to claim 1 or 2, wherein: The plurality of materials having different elastic moduli include a material having the same refractive index difference as that between the core and the cladding, The plurality of materials having different elastic coefficients include: a first refractive index material having a first refractive index, and a second refractive index material having a second refractive index lower than the first refractive index; The first refractive index material is located in the same height range as the incident surface of the core in a direction perpendicular to the first surface.

4. The optical waveguide package according to claim 3, wherein: The first refractive index material is configured to be separated from the core.

5. The optical waveguide package according to any one of claims 1 to 4, wherein The side wall includes: a first material which is the same material as the core, and a second material which is the same material as the cladding and is arranged in a manner of sandwiching the first material. The first material has a higher modulus of elasticity than the second material.

6. The optical waveguide package according to any one of claims 1 to 4, wherein: The side wall includes: a first material which is the same material as the core, and a second material which is the same material as the cladding and is arranged in a manner of sandwiching the first material. The first material has a lower modulus of elasticity than the second material.

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