Optical modules and optical connector cables

Abstract

This optical module comprises: a substrate; an optical element; and an optical coupling module. The substrate has a glass cloth formed of glass threads serving as weft and warp. The outer edge of the substrate has a rectangular shape delimited by a pair of first lateral surfaces along a predetermined direction and a pair of second lateral surfaces along a direction perpendicular to the predetermined direction. The optical coupling module is optically coupled to the optical element. The weft is inclined with respect to the first and second lateral surfaces. The warp is inclined with respect to the first and second lateral surfaces. A cavity is formed in the substrate. At least a portion of the optical coupling module is housed in the cavity. A lateral surface of the cavity includes an inclined region that is inclined with respect to the extension direction of the weft and the extension direction of the warp.

Description

Technical Field

[0004] ,

[0001] The present disclosure relates to an optical module and an optical connector cable. This application claims priority based on Japanese Application No. 2021-128994 filed on August 5, 2021, and incorporates all the descriptions described in the above Japanese application.

Background Art

[0002] Patent Document 1 discloses an optical component as an example of an optical module including a substrate on which an optical element is mounted and an optical coupling module optically coupled to the optical element. In the optical module, light emitted from an optical fiber held by the optical coupling module is incident on the optical element mounted on the substrate through the optical coupling module.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

[0004] The optical module of this disclosure comprises a substrate, an optical element, and an optical coupling module. The substrate has a glass cloth inside, composed of glass threads as weft and warp threads. The outer edge of the substrate, when viewed from the thickness direction, has a rectangular shape defined by a pair of first sides along a predetermined direction and a pair of second sides along a direction perpendicular to the predetermined direction. The optical element is mounted on the substrate. The optical coupling module is configured to optically couple with the optical element. The weft threads are inclined with respect to the first and second sides when viewed from the thickness direction of the substrate. The warp threads are inclined with respect to the first and second sides when viewed from the thickness direction of the substrate. The substrate has a cavity formed therein that is recessed from the first main surface of the substrate toward the second main surface of the substrate, having a bottom. At least a portion of the optical coupling module is housed in the cavity. The sides of the cavity include inclined regions that are inclined with respect to the direction of extension of the weft threads and the direction of extension of the warp threads when viewed from the thickness direction of the substrate.

[0005] The optical module of this disclosure comprises a substrate, an optical element, and an optical coupling module. The substrate has a glass cloth inside, composed of glass threads as weft and warp threads. The outer edge of the substrate, when viewed from the thickness direction, has a rectangular shape defined by a pair of first sides along a predetermined direction and a pair of second sides along a direction perpendicular to the predetermined direction. The optical element is mounted on the substrate. The optical coupling module is configured to optically couple with the optical element. The weft threads are along the first sides when viewed from the thickness direction of the substrate. The warp threads are along the second sides when viewed from the thickness direction of the substrate. The substrate has a cavity formed therein that is recessed from the first main surface of the substrate toward the second main surface of the substrate, having a bottom. At least a portion of the optical coupling module is housed in the cavity. The sides of the cavity include inclined regions that are inclined with respect to the direction of extension of the weft threads and the direction of extension of the warp threads when viewed from the thickness direction of the substrate. [Brief explanation of the drawing]

[0006] [Figure 1] Figure 1 is a perspective view showing the end of an optical connector cable according to one embodiment. [Figure 2]Figure 2 is a perspective view showing the end of an optical connector cable with the protective material removed. [Figure 3] Figure 3 is a plan view of the optical module as seen from above the first main surface of the substrate. [Figure 4] Figure 4 is a plan view of the optical module as seen from above the second main surface of the substrate. [Figure 5] Figure 5 is a cross-sectional view of the optical module when it is cut along the VV line shown in Figure 3. [Figure 6] Figure 6 is an enlarged view of the area enclosed by the dashed line A shown in Figure 5. [Figure 7] Figure 7 is a perspective view showing the substrate used in the optical module shown in Figure 3. [Figure 8] Figure 8 is an enlarged view of the area enclosed by the dashed line B shown in Figure 7. [Figure 9] Figure 9 is a schematic diagram of the substrate shown in Figure 7. [Figure 10] Figure 10 is a plan view of the portion of the substrate shown in Figure 7 where a cavity has been formed. [Figure 11] Figure 11 is a plan view of the optical coupling module housed in the cavity shown in Figure 7. [Figure 12] Figure 12 is a plan view of the optical coupling module housed in the cavity according to the second embodiment. [Figure 13] Figure 13 is a schematic diagram of the substrate according to the second embodiment. [Figure 14] Figure 14 is a plan view of the portion of the substrate in the second embodiment in which a cavity is formed. [Figure 15] Figure 15 shows the second cavity related to the first modified example. [Figure 16] Figure 16 shows the second cavity related to the second modified example. [Figure 17] Figure 17 shows the second cavity according to the third modified example. [Modes for carrying out the invention]

[0007] [Issues this disclosure aims to address] The optical module disclosed in Patent Document 1 has a structure in which an optical coupling module is mounted on a substrate. As a result, the overall thickness of the optical module increases by the thickness of the substrate and the optical coupling module. Therefore, in order to make the optical module thinner, a cavity is formed in the substrate that is recessed from one main surface to the other main surface, and at least a part of the optical coupling module is housed inside the cavity.

[0008] However, when forming a cavity in a substrate, a portion of the glass cloth provided within the substrate may protrude from the side of the cavity into the cavity, potentially hindering the mounting of the optical coupling module. Furthermore, if glass threads protruding from the side of the cavity are present in the optical path (for example, between the lens of the optical coupling module and the optical element mounted on the substrate), light transmission may be obstructed. Therefore, there is a need for the development of an optical module that can improve the mountability of the optical coupling module and enable more appropriate light transmission.

[0009] The purpose of this disclosure is to provide an optical module and an optical connector cable that can improve the implementability of optical coupling modules and enable proper transmission of light.

[0010] [Effects of this disclosure] According to this disclosure, the implementability of the optical coupling module can be improved, and optical transmission can be performed more appropriately.

[0011] [Description of Embodiments in this Disclosure] First, the content of the embodiments of the present disclosure will be listed and described. A light module according to an embodiment includes a substrate, an optical element, and an optical coupling module. The substrate has a glass cloth formed with glass yarns as weft and warp inside. The outer edge when viewed from the thickness direction of the substrate has a rectangular shape defined by a pair of first side surfaces along a predetermined direction and a pair of second side surfaces along a direction orthogonal to the predetermined direction. The optical element is mounted on the substrate. The optical coupling module is configured to be optically coupled to the optical element. The weft is inclined with respect to the first side surface and the second side surface when viewed from the thickness direction of the substrate. The warp is inclined with respect to the first side surface and the second side surface when viewed from the thickness direction of the substrate. A cavity that recesses from the first main surface of the substrate toward the second main surface is formed in the substrate so as to have a bottom. At least a part of the optical coupling module is accommodated in the cavity. The side surface of the cavity includes an inclined region that is inclined with respect to the extending direction of the weft and the extending direction of the warp when viewed from the thickness direction of the substrate.

[0012] In this light module, the side surface of the cavity includes an inclined region. Since this inclined region is inclined with respect to the extending direction of the weft and the extending direction of the warp when viewed from the thickness direction of the substrate, it is difficult for the glass yarns to protrude from the inclined region into the cavity. Therefore, the amount of glass yarns protruding from the side surface of the cavity into the cavity can be suppressed as compared with the case where the entire side surface of the cavity is along the weft or the warp. Thereby, it is suppressed that the accommodation of the optical coupling module is hindered by the glass yarns protruding into the cavity, and the mounting property of the optical coupling module is improved. Further, it is suppressed that the glass yarns exist on the optical path (for example, between the lens of the optical coupling module and the optical element), and the light transmission is performed more appropriately.

[0013] As an embodiment, the cavity may include a first cavity and a second bottom located closer to the second main surface than the first bottom of the first cavity, and a second cavity having an opening area smaller than that of the first cavity. Each of the side surfaces of the first cavity and the side surface of the second cavity may include an inclined region. The optical coupling module has a lens that optically couples with the optical element, and the lens may be housed in the second cavity. In this case, only the cavity portion that mainly houses components such as the lens, which is likely to protrude from the lower surface of the optical coupling module, is made deeper, and the other portions are made shallower than that, so that the area of the entire cavity can be made smaller. As a result, even in a configuration where a cavity is provided in the substrate, the strength of the substrate can be maintained.

[0014] An optical module according to an embodiment includes a substrate, an optical element, and an optical coupling module. The substrate has a glass cloth inside formed with glass yarns as weft and warp. The outer edge when viewed from the thickness direction of the substrate has a rectangular shape defined by a pair of first side surfaces along a predetermined direction and a pair of second side surfaces along a direction orthogonal to the predetermined direction. The optical element is mounted on the substrate. The optical coupling module is configured to optically couple with the optical element. The weft is along the first side surface when viewed from the thickness direction of the substrate. The warp is along the second side surface when viewed from the thickness direction of the substrate. A cavity is formed in the substrate, recessing from the first main surface of the substrate toward the second main surface so as to have a bottom. At least a part of the optical coupling module is housed in the cavity. The side surface of the cavity includes an inclined region that is inclined with respect to the extending direction of the weft and the extending direction of the warp when viewed from the thickness direction of the substrate.

[0015] In this optical module, the sides of the cavity include a sloped region. This sloped region is inclined with respect to the extension directions of the weft and warp threads of the glass filaments when viewed from the thickness direction of the substrate, making it difficult for the glass filaments to protrude into the cavity from the sloped region. Therefore, compared to a case where the entire side of the cavity is aligned with the weft or warp threads, the amount of glass filaments protruding from the side of the cavity into the cavity can be suppressed. This reduces the obstruction of the optical coupling module's housing by protruding glass filaments into the cavity, improving the mountability of the optical coupling module. Furthermore, the presence of glass filaments in the optical path is suppressed, resulting in more appropriate light transmission.

[0016] In one embodiment, the cavity may include a first cavity and a second cavity having a smaller opening area than the first cavity, and including a second bottom located closer to the second main surface than the first bottom of the first cavity. The side surface of the second cavity may include a sloped region. The optical coupling module has a lens that optically couples with an optical element, and the lens may be housed in the second cavity. In this case, the cavity portion mainly housing components such as lenses that tend to protrude from the bottom surface of the optical coupling module can be made deeper, while other parts can be made shallower, thereby reducing the overall cavity area. As a result, the strength of the substrate can be maintained even when a cavity is provided in the substrate.

[0017] In one embodiment, the inclined region may be a curved surface when viewed from the thickness direction of the substrate. The outer edge of the cavity when viewed from the thickness direction of the substrate may have an elliptical or sectoral shape defined by the side surface of the cavity. In this case, a cavity having a side surface including the inclined region can be easily formed with a simple configuration.

[0018] In one embodiment, the outer edge of the cavity, when viewed from the thickness direction of the substrate, may have a rhombic or triangular shape defined by the side surface of the cavity. In this case, a cavity having a side surface including a sloping region can be easily formed with a simple configuration.

[0019] In one embodiment, the angle between the inclined region and the direction of extension of the weft threads, when viewed from the thickness direction of the substrate, may be between 10° and 80°. The angle between the inclined region and the direction of extension of the warp threads, when viewed from the thickness direction of the substrate, may be between 10° and 80°. In this case, it is possible to more reliably prevent the glass threads from protruding from the inclined region into the cavity. As a result, the mountability of the optical coupling module is further improved, and light transmission is performed more appropriately.

[0020] In one embodiment, the optical coupling module may have a holding portion that holds the end of the optical fiber that is optically coupled to the optical element via the optical coupling module. In this case, since the end of the optical fiber is properly held by the holding portion of the optical coupling module, it becomes possible to achieve more precise optical coupling between the optical element and the optical fiber.

[0021] In one embodiment, a through-hole may be formed in the cavity, extending from the bottom through to the second main surface. The optical element may be mounted on the second main surface such that it overlaps with the through-hole when viewed from above. In this case, the optical coupling module and the optical element mounted on the second main surface of the substrate can be optically coupled via the simple configuration of the through-hole.

[0022] An optical connector cable according to one embodiment comprises one of the optical modules described above and at least one optical fiber cable. The optical fiber cable has an optical fiber. The optical fiber cable is attached to the optical module so that the optical fiber is optically coupled to an optical element via an optical coupling module. Similar to the optical module described above, this optical connector cable can improve the mountability of the optical coupling module and enable proper transmission of light.

[0023] [Details of the embodiments of this disclosure] Specific examples of optical modules and optical connector cables relating to this disclosure are described below with reference to the drawings. This disclosure is not limited to these examples, but is as indicated by the claims, and all changes within the meaning and scope of the claims are intended to be included. In the description of the drawings, identical elements are denoted by the same reference numerals, and redundant descriptions are omitted.

[0024] <First Embodiment> An optical connector cable 1 according to one embodiment will be described with reference to Figures 1 and 2. Figure 1 is a perspective view showing the end of the optical connector cable 1 according to one embodiment. Figure 2 is a perspective view showing the end of the optical connector cable 1 with the protective member 20 removed. For the purposes of this description, the width direction of the end of the optical connector cable 1 will be referred to as direction X, the extension direction of the end as direction Y, and the thickness direction of the end as direction Z. In this embodiment, directions X, Y, and Z are orthogonal to each other.

[0025] The optical connector cable 1 is a cable used, for example, to send and receive optical signals between devices. As shown in Figures 1 and 2, the optical connector cable 1 comprises an optical fiber cable 10, a protective member 20, and an optical module 30. Although Figures 1 and 2 show one end of the optical fiber cable 10, the other end of the optical fiber cable 10 may have a similar configuration.

[0026] As shown in Figure 2, the optical fiber cable 10 has a plurality of optical fibers 11 and a cable sheath 12. Each optical fiber 11 is a component for transmitting optical signals. Most of each optical fiber 11 is housed inside the cable sheath 12. The tip portion of each optical fiber 11 is exposed outside the cable sheath 12. The plurality of optical fibers 11 are arranged in a one-dimensional manner along direction X. Inside the cable sheath 12, all the optical fibers 11 are housed together in close proximity to each other. On the other hand, outside the cable sheath 12, the plurality of optical fibers 11 branch into bundles of several (four to six in this embodiment), and the ends of each bundle are held by each optical coupling module 50. Each optical fiber 11 has, for example, a glass fiber and a coating resin. The glass fiber includes, for example, a core and a cladding surrounding the core. Each optical fiber 11 may be a single-mode optical fiber (SMF) or a multimode optical fiber (MMF).

[0027] As shown in Figure 1, the protective member 20 is a member that has a flattened shape that extends along directions X and Y. The optical module 30 is housed inside the protective member 20. The protective member 20 protects the optical module 30 from external impacts, etc. The protective member 20 has a laminated structure consisting of an inner layer 21 and an outer layer 22 that covers the inner layer 21. The inner layer 21 is made of, for example, metal. The outer layer 22 is made of, for example, resin. At the tip of the optical connector cable 1, a part of the inner layer 21 is exposed from the outer layer 22. The exposed portion of the inner layer 21 is inserted, for example, into a receptacle provided in the device to which the optical connector cable 1 is connected.

[0028] Next, the optical module 30 will be described with reference to Figures 3 to 6. Figure 3 is a plan view of the optical module 30 as seen from above the first main surface 41 of the substrate 40. Figure 4 is a plan view of the optical module 30 as seen from above the second main surface 42 of the substrate 40. Figure 5 is a cross-sectional view of the optical module 30 when it is cut along the VV line shown in Figure 3. Figure 6 is an enlarged view of the portion enclosed by the dashed line A shown in Figure 5. The optical module 30 comprises a substrate 40, a plurality of optical coupling modules 50, a plurality of optical elements 60, and a plurality of ICs 61.

[0029] The substrate 40 is a plate-shaped member on which various optical and electronic elements are mounted. The substrate 40 is a multilayer substrate composed of multiple resin layers laminated together, or a single-layer substrate composed of one resin layer. The resin layers are made of, for example, epoxy resin, polyimide resin, or fluororesin. In this embodiment, the thickness direction of the substrate 40 coincides with direction Z. The substrate 40 has a pair of side surfaces 40a, 40b (first side surfaces) and a pair of side surfaces 40c, 40d. When viewed from direction Z, the side surfaces 40a, 40b are aligned with direction X (a predetermined direction). When viewed from direction Z, the side surfaces 40c, 40d are aligned with direction Y (a direction perpendicular to the predetermined direction). When viewed from direction Z, the outer edge of the substrate 40 is rectangular, defined by the pair of side surfaces 40a, 40b and the pair of side surfaces 40c, 40d. That is, the substrate 40 is a rectangular substrate. The substrate 40 has a first main surface 41 and a second main surface 42 that are opposite each other in direction Z. The thickness of the substrate 40 may be 0.2 mm or more and 0.8 mm or less.

[0030] The substrate 40 has at least one glass cloth 70 inside. The glass cloth 70 is a woven fabric composed of glass threads as warp and weft threads. In Figures 3 and 4, only a portion of the glass cloth 70 is shown for ease of explanation, but in this embodiment, the glass cloth 70 is provided over the entire area of ​​the substrate 40 when viewed from direction Z. That is, the outer edge of the glass cloth 70 when viewed from direction Z coincides with the outer edge of the substrate 40. If the substrate 40 is a multilayer substrate, the glass cloth 70 may be provided on each of the multiple resin layers constituting the substrate 40. In this embodiment, the substrate 40 is a multilayer substrate, and multiple glass cloths 70 are stacked in direction Z. The detailed configuration of the glass cloth 70 will be described later.

[0031] Inside the substrate 40, various wirings (not shown) are provided for electrically connecting IC 61 and other electronic components. In the following description, the end where side surface 40a is located in direction Y may be referred to as the front end of the optical module 30, and the end where side surface 40b is located may be referred to as the base end of the optical module 30. Also, the surface where the first main surface 41 is located in direction Z may be referred to as the top surface of the optical module 30, and the surface where the second main surface 42 is located may be referred to as the bottom surface of the optical module 30.

[0032] As shown in Figure 3, the first main surface 41 is a surface aligned with directions X and Y, and has a rectangular shape in plan view. Multiple patterns 41a, which are metal films, are provided in the region of the first main surface 41 near the side surface 40a. Each pattern 41a may be connected to the IC 61, for example, via wiring in the substrate 40. On the other hand, multiple optical coupling modules 50 are mounted in a line along direction X in the region of the first main surface 41 near the side surface 40b.

[0033] As shown in Figure 4, the second main surface 42 is a surface aligned with directions X and Y, and has a rectangular shape in plan view. Multiple optical elements 60 and multiple ICs 61 are mounted in the region of the second main surface 42 near the side surface 40b. In Figure 4, for ease of explanation, each optical element 60 is shown with a dashed line. Each optical element 60 is a light-receiving element such as a photodiode (PD). The light-receiving surface of each optical element 60 faces the optical coupling module 50. Each optical element 60 overlaps with each through-hole 48a provided in the substrate 40 when viewed from above (in direction Z) on the second main surface 42. As a result, the optical elements 60 can receive light from the optical coupling module 50, which is facing them across the substrate 40, through the through-hole 48a. The opening area of ​​the through-hole 48a on the second main surface 42 is smaller than the surface area of ​​the surface of the optical element 60 facing the second main surface 42 in order to position the optical element 60 on the second main surface 42. Each IC 61 is an integrated circuit that controls the operation of the optical element 60. Each IC 61 may be connected to the optical element 60 via, for example, wiring or bonding wires in the substrate 40. In this embodiment, one IC 61 is connected to three optical elements 60. By placing the IC 61 close to the optical elements 60 (for example, adjacent to them), the communication speed between the IC 61 and the optical elements 60 can be maintained at a high level.

[0034] The optical coupling module 50 is a component that optically couples the optical fiber 11 and the optical element 60. The optical coupling module 50 is made of a material that transmits light emitted from the optical fiber 11 (for example, glass or a light-transmitting resin). As shown in Figure 3, the optical coupling module 50 has a substantially rectangular shape when viewed from direction Z. The optical coupling module 50 has a front surface 50a and a pair of side surfaces 50b. The front surface 50a is a surface that aligns with directions X and Z and connects the pair of side surfaces 50b. Each side surface 50b is a surface that aligns with directions Y and Z.

[0035] Furthermore, as shown in Figure 5, the optical coupling module 50 has a groove 51, an upper surface 52, a lower surface 53, a stopper surface 54, a mirror 55, and a lens 56. The groove 51 is a V-groove (a groove forming a V shape in the XZ cross section) extending along the direction Y, and is a holding part that holds the end of the optical fiber 11. The groove 51 defines the position of the optical fiber 11 relative to the optical coupling module 50 and prevents misalignment of the optical fiber 11 in the direction X. The end of the optical fiber 11 placed in the groove 51 is fixed to the groove 51 by, for example, an adhesive. The adhesive may be, for example, an ultraviolet-curable adhesive, or a light-transmitting adhesive that transmits light L emitted from the optical fiber 11. The shape of the groove 51 is not limited to a V-groove. The shape of the groove 51 may be, for example, a U-groove with a rounded bottom, or a rectangular groove having a bottom surface along the directions X and Y. The retaining portion (groove portion 51 in this embodiment) that holds the end of the optical fiber 11 does not necessarily have to be provided on the optical coupling module 50. For example, the groove portion 51 may be provided on a separate component different from the optical coupling module 50. If the groove portion 51 is provided on a separate component, for example, the optical coupling module 50 may have a pair of protrusions, and the separate component on which the groove portion 51 is provided may have a pair of recesses, and the optical coupling module 50 and the separate component may be connected by each protrusion of the optical coupling module 50 fitting into each recess of the separate component.

[0036] The upper surface 52 is located on the upper part of the optical coupling module 50 and is aligned with directions X and Y. The upper surface 52 is located closer to the tip surface 50a of the optical coupling module 50 relative to the groove 51. The upper surface 52 is provided with a recess whose surface functions as a mirror 55. The lower surface 53 is located on the lower part of the optical coupling module 50 and is aligned with directions X and Y.

[0037] The abutment surface 54 is the surface that the tip of the optical fiber 11 abuts against, and is aligned with directions X and Z. The abutment surface 54 connects the end of the groove 51 and the end of the upper surface 52 in direction Y. Light L emitted from the optical fiber 11 passes through the abutment surface 54 and enters the mirror 55. The abutment surface 54 and the tip of the optical fiber 11 do not have to be in direct contact. A light-transmitting adhesive or refractive index matching agent that transmits light L may be present between the abutment surface 54 and the tip of the optical fiber 11.

[0038] The mirror 55 is a component that changes the propagation direction of light L emitted from the optical fiber 11. The mirror 55 is positioned at an angle to the XY plane and the XZ plane, respectively. The mirror 55 receives light L emitted from the optical fiber 11 along direction Y and reflects the light L toward the lens 56 so that it is aligned with direction Z. The incident optical axis and the reflected optical axis of the light L may be perpendicular to each other, for example. The light L reflected by the mirror 55 enters the optical element 60 through the lens 56 and the through hole 48a.

[0039] The lens 56 is a component that optically couples with the optical element 60. The lens 56 is provided on a portion of the optical coupling module 50 that protrudes toward the second principal surface 42 in direction Z. As shown in Figure 6, the lens 56 faces the optical element 60 in direction Z and has a surface that curves convexly toward the optical element 60. The focal point F of the lens 56 is located inside the optical element 60, rather than on its surface. The lens 56 focuses the light L reflected by the mirror 55 and directs it into the optical element 60. Various parameters of the lens 56 (e.g., surface shape, size, material, etc.) are optimized so that the focal point F of the lens 56 is located inside the optical element 60.

[0040] Next, the detailed configuration of the substrate 40 will be described with reference to Figures 7 and 8. Figure 7 is a perspective view showing the substrate 40. Figure 8 is an enlarged view of the portion enclosed by the dashed line B shown in Figure 7. For convenience of explanation, the optical coupling module 50 is not shown in Figures 7 and 8. As shown in Figure 7, a plurality of cavities 43 are formed in the substrate 40. Each cavity 43 is a recess that extends from the first main surface 41 toward the second main surface 42. An optical coupling module 50 is housed inside each cavity 43. The plurality of cavities 43 are arranged in a line along direction X. The number of cavities 43 may be the same as or greater than the number of optical coupling modules 50 mounted on the substrate 40. In this embodiment, the same number of cavities 43 as the number of optical coupling modules 50 (four) are formed. Each cavity 43 may be formed, for example, by counterboring. Between adjacent cavities 43, beam portions 43a are provided that extend from the inside to the outside of the substrate 40 along the direction Y. The beam portions 43a are shaped to rise from the first bottom portion 45 of each cavity 43 toward the first main surface 41 of the substrate 40.

[0041] Each cavity 43 includes a first cavity 44 and a second cavity 47. The first cavity 44 is a recess that constitutes most of the cavity 43 and has a first bottom 45 and a side surface 46. The first bottom 45 is the portion on which the optical coupling module 50 is placed, and in this embodiment, it is a surface along directions X and Y. When viewed from direction Z, the outer edge of the first bottom 45 has a rectangular shape with a longer side along direction Y. The first bottom 45 is large enough to accommodate the entire optical coupling module 50. Placing the optical coupling module 50 on the first bottom 45 includes not only cases where the optical coupling module 50 is placed in direct contact with the first bottom 45, but also cases where the optical coupling module 50 is placed on the first bottom 45 via other materials such as adhesive.

[0042] The first bottom portion 45 has a pair of positioning holes 45a, as shown in Figure 8. Each positioning hole 45a is a hole that penetrates from the first bottom portion 45 toward the second main surface 42 (see Figure 4). The pair of positioning holes 45a function as a positioning mechanism for the optical coupling module 50 relative to the cavity 43. For example, the optical coupling module 50 may be provided with a pair of protrusions corresponding to the pair of positioning holes 45a, and the optical coupling module 50 may be placed so that each of the pair of protrusions fits into each of the pair of positioning holes 45a, thereby suitably optically coupling the lens 56 (see Figure 5). The number of positioning holes 45a may be one, but the formation of two or more positioning holes 45a allows for more precise positioning of the optical coupling module 50. Each positioning hole 45a does not need to penetrate from the first bottom portion 45 toward the second main surface 42; it may be a non-through hole with a bottom surface.

[0043] The configuration of the positioning mechanism used to position the optical coupling module 50 is not limited to the positioning hole 45a. For example, marks may be provided on both the first bottom portion 45 and the optical coupling module 50, and the optical coupling module 50 may be placed at a position where the marks overlap, thereby suitably optically coupling the lens 56 of the optical coupling module 50 and the optical element 60. In this case, in order to make the marks provided on the first bottom portion 45 visible through the optical coupling module 50, the material of the optical coupling module 50 may be a material that transmits visible light (for example, glass or a light-transmitting resin).

[0044] Side surface 46 is the surface connecting the first bottom 45 and the first main surface 41. Side surface 46 is the surface that rises from the outer edge of the first bottom 45 toward the first main surface 41 of the substrate 40. Side surface 46 defines the outer edge of the first cavity 44 when viewed from direction Z. Side surface 46 may be parallel to direction Z or it may be inclined. Side surface 46 includes side surface 46a and a pair of side surfaces 46b. Side surface 46a is the surface located at the end of the first cavity 44 closer to side surface 40a, as shown in Figure 7, and connects the pair of side surfaces 46b. Side surface 46a is aligned with direction X when viewed from direction Z. The corner where side surface 46a and the first bottom 45 intersect may have a rounded shape.

[0045] The pair of side surfaces 46b are faces opposite each other in direction X. Each side surface 46b is aligned with direction Y when viewed from direction Z. The corners where each side surface 46b intersects with the first bottom 45 may have a rounded shape. Furthermore, the end of the first cavity 44 near side surface 40b does not have a side surface. That is, the cavity 43 is open at side surface 40b. This allows the optical coupling module 50 to be housed inside the cavity 43 through this opening. Also, with the optical coupling module 50 housed in the cavity 43, the optical fiber 11 connected to the optical coupling module 50 can be led out of the cavity 43 through this opening.

[0046] As shown in Figure 8, the second cavity 47 is a recess provided in the first bottom 45 of the first cavity 44. The second cavity 47 is formed to extend along direction X. The second cavity 47 has a smaller opening area than the first cavity 44. The opening area of ​​the second cavity 47 is the opening area at the first bottom 45, and the opening area of ​​the first cavity 44 is the opening area at the first main surface 41. The second cavity 47 has a second bottom 48 and a side surface 49. The second bottom 48 is located closer to the second main surface 42 than the first bottom 45. In this embodiment, the second bottom 48 is a surface along directions X and Y. When viewed from direction Z, the outer edge of the second bottom 48 has a rectangular shape with a longer side along direction X. A portion of the optical coupling module 50 (the portion where the lens 56 is formed) is placed on the second bottom portion 48 (see Figure 5). The lens 56 is housed in the second cavity 47.

[0047] Multiple through holes 48a are formed in the second bottom portion 48. In this embodiment, two round holes and one elongated hole are formed as through holes 48a for each second cavity 47. The number and shape of the through holes 48a are not limited and may be appropriately changed depending on the number or shape of the optical elements 60 mounted on the second main surface 42. As shown in Figure 6, the through holes 48a penetrate from the second bottom portion 48 to the second main surface 42. Light L from the lens 56 toward the optical elements 60 passes through the inside of the through holes 48a. The through holes 48a have a tapered shape in which the inner diameter decreases from the second bottom portion 48 toward the second main surface 42. The inner diameter and taper angle of the through holes 48a are optimized to a size that does not obstruct the path of light L. The through holes 48a may also be straight through holes with a constant inner diameter.

[0048] Side surface 49 is the surface connecting the second bottom 48 and the first bottom 45. Side surface 49 is the surface rising from the outer edge of the second bottom 48 toward the first bottom 45. Side surface 49 defines the outer edge of the second cavity 47 when viewed from direction Z. Side surface 49 may be parallel to direction Z or it may be inclined. Side surface 49 includes a pair of side surfaces 49a and a pair of side surfaces 49b. The pair of side surfaces 49a are surfaces facing each other in direction Y. Each side surface 49a connects to the pair of side surfaces 49b. Each side surface 49a is aligned with direction X when viewed from direction Z. The corners where each side surface 49a intersects with the second bottom 48 may have a rounded shape. The pair of side surfaces 49b are surfaces facing each other in direction X. Each side surface 49b is aligned with direction Y when viewed from direction Z. The corners where each side surface 49b intersects with the second bottom portion 48 may have an R-shape.

[0049] The glass cloth 70 will be described in detail with reference to Figure 9. Figure 9 is a schematic diagram of the substrate 40. Figure 9 shows the substrate 40 before the multiple cavities 43 are formed. In Figure 9, the various components such as the optical element 60 and IC 61 provided on the substrate 40 are not shown.

[0050] As shown in Figure 9, a glass cloth 70 is provided inside the substrate 40. The glass cloth 70 is a woven fabric composed of glass threads 71 ​​as weft threads 72 and warp threads 73. The glass cloth 70 has a mesh-like sheet structure. In the glass cloth 70, the weft threads 72 and warp threads 73 intersect each other regularly. The weaving density of the weft threads 72 and the weaving density of the warp threads 73 are, for example, 50 threads / 25 mm or more and 100 threads / 25 mm or less. The glass threads 71 ​​that make up the weft threads 72 and warp threads 73 consist of bundles of glass filaments of, for example, several hundred threads (for example, 100 to 500 threads). The diameter of each glass filament is, for example, several micrometers (for example, 1 micrometer to 10 micrometers). In Figure 9, for the sake of explanation, the spacing between the weft threads 72 and the warp threads 73 is shown to be larger than the actual spacing.

[0051] The weft thread 72 is inclined with respect to directions X and Y when viewed from direction Z. That is, the weft thread 72 is inclined with respect to sides 40a, 40b and sides 40c, 40d when viewed from direction Z. The angle (acute angle) between the extending direction of the weft thread 72 and sides 40a, 40b when viewed from direction Z may be, for example, 10° or more and 80° or 40° or more and 50° or less. In this embodiment, the angle between the extending direction of the weft thread 72 and sides 40a, 40b is 45°. Similarly, the angle (acute angle) between the extending direction of the weft thread 72 and sides 40c, 40d when viewed from direction Z may be, for example, 10° or more and 80° or 40° or more and 50° or less. In this embodiment, the angle between the extending direction of the weft thread 72 and sides 40c, 40d The angle formed by them is 45°.

[0052] The warp threads 73 are inclined with respect to directions X and Y when viewed from direction Z. That is, the warp threads 73 are inclined with respect to sides 40a, 40b and sides 40c, 40d when viewed from direction Z. The angle (acute angle) between the direction of extension of the warp threads 73 and sides 40a, 40b when viewed from direction Z may be, for example, 10° to 80° or 40° to 50°. In this embodiment, the angle between the direction of extension of the warp threads 73 and sides 40a, 40b is 45°. Similarly, the angle (acute angle) between the direction of extension of the warp threads 73 and sides 40c, 40d when viewed from direction Z may be, for example, 10° to 80° or 40° to 50°. In this embodiment, the angle between the direction of extension of the warp threads 73 and sides 40c, 40d is 45°.

[0053] A cavity 43 is formed in the substrate 40 on which the glass cloth 70 is placed, for example, by counterboring. The relationship between the cavity 43 and the glass cloth 70 will be explained with reference to Figure 10. Figure 10 is a plan view of the portion of the substrate 40 where the cavity 43 is formed. In Figure 10, for the sake of explanation, the spacing between the weft threads 72 and the warp threads 73 is shown to be larger than the actual spacing. Also, in Figure 10, the portion of the glass cloth 70 provided inside the substrate 40 that overlaps with the cavity 43 is not shown, but in reality, glass cloth 70 is also provided between the first bottom portion 45 and the second bottom portion 48 and the second main surface 42 (see Figure 5).

[0054] As described above, the first cavity 44 has a side surface 46a and a pair of side surfaces 46b. Side surface 46a is aligned with direction X when viewed from direction Z. Therefore, side surface 46a is inclined with respect to the extending direction of the weft 72 and the extending direction of the warp 73 when viewed from direction Z. Side surface 46b is aligned with direction Y when viewed from direction Z. Therefore, side surface 46b is inclined with respect to the extending direction of the weft 72 and the extending direction of the warp 73 when viewed from direction Z.

[0055] Side surface 46 includes an inclined region S1 that, when viewed from direction Z, is inclined with respect to the extending direction of the weft 72 and the extending direction of the warp 73. In this embodiment, the entire areas of side surfaces 46a and 46b constitute the inclined region S1. The angle (acute angle) between the inclined region S1 and the extending direction of the weft 72 when viewed from direction Z may be, for example, 10° or more and 80° or less, and in this embodiment, it is 45° as an example. Also, the angle (acute angle) between the inclined region S1 and the extending direction of the warp 73 when viewed from direction Z may be, for example, 10° or more and 80° or less, or 40° or more and 50° or less. In this embodiment, the angle between the inclined region S1 and the extending direction of the warp 73 is 45°.

[0056] The second cavity 47 has a pair of sides 49a and a pair of sides 49b. Side 49a is aligned with direction X when viewed from direction Z. Therefore, side 49a is inclined with respect to the extending direction of the weft 72 and the extending direction of the warp 73 when viewed from direction Z. Side 49b is aligned with direction Y when viewed from direction Z. Therefore, side 49b is inclined with respect to the extending direction of the weft 72 and the extending direction of the warp 73 when viewed from direction Z.

[0057] The side surface 49 includes an inclined region S2 that, when viewed from direction Z, is inclined with respect to the extending direction of the weft 72 and the extending direction of the warp 73. In this embodiment, the entire areas of side surfaces 49a and 49b constitute the inclined region S2. The angle (acute angle) between the inclined region S2 and the extending direction of the weft 72 when viewed from direction Z may be, for example, 10° or more and 80° or less, and in this embodiment, it is 45° as an example. Also, the angle (acute angle) between the inclined region S2 and the extending direction of the warp 73 when viewed from direction Z may be, for example, 10° or more and 80° or less, or 40° or more and 50° or less. In this embodiment, the angle between the inclined region S2 and the extending direction of the warp 73 is 45°.

[0058] Referring to Figures 5 and 11, the configuration in which the optical coupling module 50 is housed in the cavity 43 will be described. Figure 11 is a plan view of the optical coupling module 50 housed in the cavity 43. In Figure 11, as in Figure 10, the spacing between the weft threads 72 and the warp threads 73 is shown to be larger than the actual spacing, and the portion of the glass cloth 70 provided inside the substrate 40 that overlaps with the first bottom 45 and the second bottom 48 is omitted from the illustration.

[0059] As shown in Figure 5, the optical coupling module 50 is mostly housed in the first cavity 44, and the portion where the lens 56 is provided (the portion protruding downward along direction Z) is housed in the second cavity 47. The portion of the optical fiber 11 located on the substrate 40 (the mounting portion) extends along the first main surface 41 of the substrate 40. The central axis of the mounting portion is located inside the cavity 43. The end of the optical fiber 11 extends straight along the side surface 40b of the substrate 40 without bending.

[0060] The depth D1 of the first cavity 44 is optimized, for example, according to the thickness T of the optical coupling module 50. Here, the depth D1 is the distance from the first main surface 41 to the first bottom 45 in the thickness direction (direction Z) of the substrate 40. The thickness T is the distance from the top surface 52 to the bottom surface 53 in direction Z. The depth D1 may be more than half the thickness T of the optical coupling module 50. In this embodiment, the depth D1 is more than half the thickness of the substrate 40 (distance from the first main surface 41 to the second main surface 42). When the thickness of the substrate 40 is 10, the depth D1 may be, for example, 6 or more and 8 or less. The larger the depth D1, the more of the optical coupling module 50 is housed in the cavity 43, so the optical module 30 can be made thinner. In this embodiment, the upper surface 52 is located outside the cavity 43 (above the first main surface 41), but the depth D1 may be made even larger so that the upper surface 52 is located inside the cavity 43 (at the same height as the first main surface 41 or below the first main surface 41).

[0061] The depth D2 of the second cavity 47 is greater than the depth D1. Here, the depth D2 is the distance from the first main surface 41 to the second bottom 48 in the thickness direction of the substrate 40. When the thickness of the substrate 40 is 10, the depth D2 may be, for example, between 7 and 9. The depth D2 may be optimized according to, for example, the thickness T of the optical coupling module 50.

[0062] As shown in Figure 11, in this embodiment, the entire optical coupling module 50 is placed on the substrate 40. The entire optical coupling module 50 does not have to be placed on the substrate 40; a part of the optical coupling module 50 may be placed outside the substrate 40 (at a position that does not overlap with the substrate 40 in direction Z). For example, the base end portion of the optical coupling module 50 (the lower portion in Figure 10) may be placed outside the substrate 40.

[0063] The optical coupling module 50 is housed in the cavity 43 such that a gap 80 is provided between the side surface 46 and the optical coupling module 50. Specifically, a gap 81 is provided between the front surface 50a and the side surface 46a, and gaps 82 are provided between each side surface 50b and each side surface 46b. The width W1 of the gap 81 in direction Y may be, for example, 50 μm or more and 500 μm or less. The width W2 of the gap 82 in direction X may be, for example, 50 μm or more and 750 μm or less. The width W2 may be greater than the width W1.

[0064] The optical coupling module 50 is fixed to the substrate 40 using adhesive 85. The adhesive 85 is placed between the bottom surface 53 and the first bottom portion 45, as shown in Figure 5. To prevent the optical path of light L from being obstructed by the adhesive 85, the adhesive 85 does not need to be placed inside the second cavity 47. Also, the adhesive 85 is placed in the gap 81, as shown in Figure 11. The adhesive 85 is applied to the first bottom portion 45, and the optical coupling module 50 is placed on top of the applied adhesive 85. As a result, the adhesive 85 is spread out, for example by the weight of the optical coupling module 50, and flows into the gaps 81 and 82. The adhesive 85 is, for example, an ultraviolet-curable adhesive or a light-transmitting adhesive. The amount of adhesive 85 applied per optical coupling module 50 is, for example, 1 mg to 10 mg.

[0065] As described above, in the optical module 30 and optical connector cable 1 according to this embodiment, the sides 46 and 49 of the cavity 43 include inclined regions S1 and S2. Since the inclined regions S1 and S2 are inclined with respect to the extending direction of the weft thread 72 and the extending direction of the warp thread 73 when viewed from direction Z, the glass thread 71 is less likely to protrude from the inclined regions S1 and S2 into the interior of the cavity 43. Therefore, compared to the case where the entire area of ​​the sides 46 and 49 of the cavity 43 is aligned with the weft thread 72 or warp thread 73, the amount of glass thread 71 protruding from the sides 46 and 49 of the cavity 43 into the interior of the cavity 43 can be suppressed. As a result, the housing of the optical coupling module 50 is less likely to be hindered by the glass thread 71 protruding into the cavity 43, and the mountability of the optical coupling module 50 is improved. Furthermore, the presence of glass thread 71 on the optical path (for example, between the lens 56 and the optical element 60) is suppressed, and the transmission of light L is performed more appropriately.

[0066] In the above embodiment, the angle between the inclined regions S1 and S2 and the extending direction of the weft thread 72 when viewed from direction Z may be between 10° and 80°. The angle between the inclined regions S1 and S2 and the extending direction of the warp thread 73 when viewed from direction Z may be between 10° and 80°. In this case, it is possible to more reliably prevent the glass thread 71 from protruding from the sides 46 and 49 of the cavity 43 into the interior of the cavity 43. As a result, the mountability of the optical coupling module 50 is further improved, and the transmission of light L is performed more appropriately.

[0067] In the above embodiment, the optical coupling module 50 has a groove 51 (holding portion) that holds the end of the optical fiber 11 which is optically coupled with the optical element 60 via the optical coupling module 50. In this case, the end of the optical fiber 11 is properly held by the groove 51 of the optical coupling module 50, so that the optical coupling between the optical element 60 and the optical fiber 11 can be made more precise.

[0068] In the above embodiment, a through-hole 48a is formed in the cavity 43, penetrating from the second bottom portion 48 to the second main surface 42. The optical element 60 is mounted on the second main surface 42 such that, when viewed from above (in direction Z), it overlaps with the through-hole 48a. In this case, the optical coupling module 50 and the optical element 60 mounted on the second main surface 42 of the substrate 40 can be optically coupled via the simple configuration of the through-hole 48a.

[0069] In the above embodiment, the cavity 43 has a first cavity 44 closer to the first main surface 41 and a second cavity 47 having a second bottom 48 located closer to the second main surface 42 than the first bottom 45 of the first cavity 44. In this case, the cavity portion (second cavity 47 portion) that mainly accommodates components such as the lens 56 which tend to protrude from the lower surface 53 of the optical coupling module 50 can be made deeper, while the other portion (first cavity 44 portion) can be made shallower, thereby making the overall area of ​​the cavity 43 smaller. As a result, the strength of the substrate 40 can be maintained even when a cavity 43 is provided in the substrate 40.

[0070] <Second Embodiment> The optical module 130 according to the second embodiment will be described with reference to Figures 12 to 14. Figure 12 is a plan view of the optical coupling module 50 housed in the cavity 143 according to the second embodiment. Figure 13 is a schematic diagram of the substrate 140 according to the second embodiment. Figure 13 shows the substrate 140 before the formation of the multiple cavities 143. Figure 14 is a plan view of the portion of the substrate 140 according to the second embodiment in which the cavities 143 are formed. In the following description, the differences from the optical module 30 according to the first embodiment will be mainly described, and similar points will be omitted from the explanation.

[0071] In the second embodiment, the orientation of the glass cloth 170 on the substrate 140 and the configuration of the second cavity 147 differ from those of the first embodiment. Other configurations of the second embodiment are the same as those of the first embodiment. As shown in Figure 13, the substrate 140 has a pair of sides 140a, 140b and a pair of sides 140c, 140d. Each side 140a, 140b is aligned with direction X (a predetermined direction) when viewed from direction Z. Each side 140c, 140d is aligned with direction Y (a direction perpendicular to the predetermined direction) when viewed from direction Z. The outer edge of the substrate 140 when viewed from direction Z is rectangular, defined by the sides 140a, 140b and sides 140c, 140d. Glass cloth 170 is provided inside the substrate 140.

[0072] The glass cloth 170 has weft threads 172 and warp threads 173. The weft threads 172 extend along direction X. That is, when viewed from direction Z, the weft threads 172 run along sides 140a and 140b and intersect sides 140c and 140d at right angles. The warp threads 173 extend along direction Y. That is, when viewed from direction Z, the warp threads 173 run along sides 140c and 140d and intersect sides 140a and 140b at right angles.

[0073] As shown in Figure 14, cavities 143 are formed in the substrate 140, for example, by counterboring. Multiple cavities 143 are formed in the substrate 140, similar to the cavity 43 in the first embodiment. Each of the multiple cavities 143 houses an optical coupling module 50. The cavity 143 has a first cavity 144 and a second cavity 147. The configuration of the first cavity 144 is the same as that of the first cavity 44. The first cavity 144 has a first bottom 145 and a side surface 146. The first bottom 145 is the surface on which the optical coupling module 50 is placed, and in this embodiment, it is aligned with directions X and Y. The side surface 146 includes a side surface 146a and a pair of side surfaces 146b. Side surface 146a is aligned with direction X when viewed from direction Z. Side surface 146b is aligned with direction Y when viewed from direction Z.

[0074] The second cavity 147 has a second bottom 148 and a side surface 149. Similar to the first embodiment, a portion of the optical coupling module 50 (the portion where the lens 56 shown in Figure 5 is formed) is placed on the second bottom 148. The second bottom 148 is aligned with directions X and Y. The outer edge of the second bottom 148, viewed from direction Z, has a rhombic shape. One axis of symmetry of the rhombic shape aligns with direction X, and the other axis of symmetry aligns with direction Y.

[0075] Side surface 149 is the surface connecting the second bottom 148 and the first bottom 145. Side surface 149 is the surface rising from the outer edge of the second bottom 148 toward the first bottom 145. Side surface 149 may be parallel to direction Z or it may be inclined. Side surface 149 includes sides 149a, 149b, 149c, and 149d. Each side surface 149a, 149b, 149c, and 149d, when viewed from direction Z, is the second bottom 148 It follows the edges of the rhombic shape exhibited by the outer edge. As a result, the outer edge of the second cavity 147, when viewed from direction Z, exhibits a rhombic shape defined by the side surface 149. Each side surface 149a, 149b, 149c, and 149d is inclined with respect to directions X and Y when viewed from direction Z.

[0076] The side surface 149 of the second cavity 147 includes an inclined region S2 that, when viewed from direction Z, is inclined with respect to the extending direction of the weft 172 (direction X) and the extending direction of the warp 173 (direction Y). In this embodiment, the entire area of ​​each side surface 149a, 149b, 149c, and 149d constitutes the inclined region S2. The angle between the inclined region S2 and the extending direction of the weft 172 when viewed from direction Z may be, for example, 10° to 80° or 40° to 50°. Similarly, the angle between the inclined region S2 and the extending direction of the warp 173 when viewed from direction Z may be, for example, 10° to 80° or 40° to 50°.

[0077] As described above, in the optical module 130 according to this embodiment, the side surface 149 of the second cavity 147 includes a sloped region S2. When viewed from direction Z, the sloped region S2 is sloped with respect to the extending direction of the weft 172 and the extending direction of the warp 173 of the glass yarn 171, so the glass yarn 171 is less likely to protrude from the sloped region S2 into the interior of the second cavity 147. Therefore, compared to the case where the entire surface 149 of the side surface 149 of the second cavity 147 is aligned with the weft 172 or warp 173, the amount of glass yarn 171 protruding from the side surface 149 of the second cavity 147 into the interior of the second cavity 147 can be suppressed. As a result, the housing of the optical coupling module 50 is less likely to be hindered by the glass yarn 171 protruding into the second cavity 147, and the mountability of the optical coupling module 50 is improved. Furthermore, the presence of the glass thread 171 in the optical path (for example, between the lens 56 and the optical element 60) is suppressed, allowing for more appropriate transmission of light L.

[0078] In the above embodiment, the outer edge of the second cavity 147, when viewed from direction Z, has a rhombic shape defined by the side surface 149. In this case, the second cavity 147 having a side surface 149 including the inclined region S2 can be easily formed with a simple configuration.

[0079] <First variation> The shape of the second cavity according to the second embodiment is not limited to the shape described above. For example, as shown in the first modified example in Figure 15, the outer edge of the second cavity 247 when viewed from direction Z may have a triangular shape defined by the side surface 249. The details of the second cavity 247 according to the first modified example will be described with reference to Figure 15.

[0080] The second cavity 247 has a second bottom 248 and a side surface 249. A portion of the optical coupling module 50 (the portion on which the lens 56 shown in Figure 5 is formed) is placed on the second bottom 248. The second bottom 248 is oriented along directions X and Y. The outer edge of the second bottom 248, when viewed from direction Z, has a triangular shape.

[0081] Side surface 249 is the surface connecting the second base 248 and the first base 145. Side surface 249 is the surface rising from the outer edge of the second base 248 toward the first base 145. Side surface 249 may be parallel to direction Z or it may be inclined. Side surface 249 includes sides 249a, 249b, and 249c. Each side surface 249a, 249b, and 249c is aligned with the sides of the triangular shape formed by the outer edge of the second base 248 when viewed from direction Z. Side surface 249a is aligned with direction X when viewed from direction Z. Side surfaces 249b and 249c are inclined with respect to directions X and Y when viewed from direction Z. That is, in this modified example, sides 249b and 249c constitute an inclined region S2 that is inclined with respect to the extending direction of the weft 172 and the extending direction of the warp 173.

[0082] In this modified example, the same effects as those of the second embodiment described above are achieved. Furthermore, in this modified example, the outer edge of the second cavity 247, when viewed from direction Z, has a triangular shape defined by the side surface 249. In this case, the second cavity 247 having a side surface 249 including the inclined region S2 can be easily formed with a simple configuration.

[0083] <Second variation> Furthermore, as shown in the second modified example in Figure 16, the outer edge of the second cavity 347, when viewed from direction Z, may have an elliptical shape defined by the side surface 349. Details of the second cavity 347 according to the second modified example will be described with reference to Figure 16.

[0084] The second cavity 347 has a second bottom 348 and a side surface 349. A portion of the optical coupling module 50 (the portion on which the lens 56 shown in Figure 5 is formed) is placed on the second bottom 348. The second bottom 348 is aligned with directions X and Y. When viewed from direction Z, the outer edge of the second bottom 348 has an elliptical shape. The major axis of the ellipse is aligned with direction X, and the minor axis is aligned with direction Y.

[0085] The side surface 349 is the surface connecting the second base 348 and the first base 145. The side surface 349 is the surface rising from the outer edge of the second base 348 toward the first base 145. The side surface 349 may be parallel to direction Z or it may be inclined. When viewed from direction Z, the side surface 349 follows the elliptical edge exhibited by the outer edge of the second base 348. In this modified example, the region of the side surface 349 that is inclined with respect to directions X and Y (the region excluding the vertex portion of the ellipse) constitutes an inclined region S2 that is inclined with respect to the extension direction of the weft 172 and the extension direction of the warp 173. The inclined region S2 in this modified example is a curved surface when viewed from direction Z.

[0086] In this modified example, the same effects as those of the second embodiment described above are achieved. Furthermore, in this modified example, the inclined region S2 is a curved surface when viewed from direction Z. The outer edge of the second cavity 347 when viewed from direction Z has an elliptical shape defined by the side surface 349. In this case, the second cavity 347 having the side surface 349 including the inclined region S2 can be easily formed with a simple configuration.

[0087] <Third variation> Furthermore, as shown in the third modified example in Figure 17, the outer edge of the second cavity 447 when viewed from direction Z may have a sector shape defined by the side surface 449. Details of the second cavity 447 according to the third modified example will be described with reference to Figure 17.

[0088] The second cavity 447 has a second bottom 448 and a side surface 449. A portion of the optical coupling module 50 (the portion on which the lens 56 shown in Figure 5 is formed) is placed on the second bottom 448. The second bottom 448 is aligned with directions X and Y. The outer edge of the second bottom 448, when viewed from direction Z, has a fan shape.

[0089] Side surface 449 is the surface connecting the second bottom 448 and the first bottom 145. Side surface 449 is the surface rising from the outer edge of the second bottom 448 toward the first bottom 145. Side surface 449 may be parallel to direction Z or it may be inclined. When viewed from direction Z, side surface 449 follows the sector-shaped edge of the outer edge of the second bottom 448. Side surface 449 includes side surface 449a and side surface 449b. When viewed from direction Z, side surface 449a follows direction X. When viewed from direction Z, side surface 449b is a curved surface connecting the two ends of side surface 449a in direction X. In this modified example, the region of the side surface 449b that is inclined with respect to directions X and Y (the region excluding the vertex of side surface 449b and the portion intersecting with side surface 449a) constitutes an inclined region S2 that is inclined with respect to the extension direction of the weft thread 172 and the extension direction of the warp thread 173. In this modified example, the inclined region S2 is a curved surface when viewed from direction Z.

[0090] In this modified example, the same effects as those of the second embodiment described above are achieved. Furthermore, in this modified example, the inclined region S2 is a curved surface when viewed from direction Z. The outer edge of the second cavity 447 when viewed from direction Z has a sector shape defined by the side surface 449. In this case, the second cavity 447 having the side surface 449 including the inclined region S2 can be easily formed with a simple configuration.

[0091] Although embodiments of the present disclosure have been described in detail above, the present disclosure is not limited to the above embodiments and can be applied to various embodiments. For example, in the above embodiments, the optical modules 30 and 130 are configured to cause light L emitted from the optical fiber 11 to be incident on the optical element 60, but they may also be configured to cause light emitted from the optical element 60 to be incident on the optical fiber 11. In this case, the optical element 60 may be a light-emitting element such as a VCSEL (Vertical Cavity Surface Emitting Laser). The light emitted from the optical element 60 may be converted into collimated light (parallel light) by the lens 56, reflected by the mirror 55, and then incident on the optical fiber 11.

[0092] In the above embodiment, the substrates 40 and 140 may be rectangular substrates with rounded corners. In the second embodiment, the side surface 146 of the first cavity 144 may include an inclined region S1 that is inclined with respect to the extending direction of the weft 172 and the extending direction of the warp 173. In this case, the outer edge of the first cavity 144, when viewed from the thickness direction (direction Z) of the substrate 140, may have a rhombus, triangular, elliptical, or sector shape defined by the side surface 146. [Explanation of symbols]

[0093] 1… Optical connector cable 10… Fiber optic cable 11… Fiber optic 12…Cable sheath 20… Protective component 21…Inner layer 22…outer layer 30,130… Optical Modules 40,140… circuit board 40a,40b,40c,40d,140a,140b,140c,140d…side 41…First main surface 41a...Pattern 42...Second main surface 43,143... Cavity 43a...beam part 44,144…First Cavity 45,145…1st bottom 45a…Positioning hole 46,46a,46b,146,146a,146b…side 47,147,247,347,447…Second Cavity 48,148,248,348,448…Second bottom 48a...Through hole 49,49a,49b,149,149a,149b,149c,149d,249,249a,249b,249c,349,449,449a,449b…side 50…Optical coupling module 50a... Tip surface 50b…side 51… Groove 52…Top surface 53…Bottom surface 55...Miller 56... Lens 60…Optical element 61…IC 70,170... glass cloth 71,171... glass thread 72,172...weft threads 73,173... warp threads 80, 81, 82… gaps 85…Adhesive F…Focus L…Light S1,S2…slope area W1…width W2...Width

Claims

1. A substrate having a glass cloth inside, composed of glass threads as the weft and warp threads, wherein the outer edge of the substrate, when viewed from the thickness direction, is rectangular in shape, defined by a pair of first sides along a predetermined direction and a pair of second sides along a direction perpendicular to the predetermined direction, The optical element mounted on the aforementioned substrate, An optical coupling module configured to optically couple with the aforementioned optical element, Equipped with, The weft thread is inclined with respect to the first and second sides when viewed from the thickness direction of the substrate. The warp threads are inclined with respect to the first and second sides when viewed from the thickness direction of the substrate. The substrate has a cavity formed therein that is recessed from the first main surface of the substrate toward the second main surface of the substrate, having a bottom, and at least a part of the optical coupling module is housed in the cavity. The side surface of the cavity includes an inclined region that, when viewed from the thickness direction of the substrate, is inclined with respect to the direction of extension of the weft threads and the direction of extension of the warp threads. The cavity comprises a first cavity and a second cavity having a smaller opening area than the first cavity, which includes a second bottom located closer to the second main surface than the first bottom of the first cavity. The optical coupling module has an upper surface and a lower surface that face each other in the thickness direction of the substrate, The distance from the first main surface to the first bottom in the thickness direction of the substrate is more than half the distance from the top surface to the bottom surface in the thickness direction of the substrate. Optical module.

2. Each of the sides of the first cavity and the second cavity includes the inclined region. The optical module according to claim 1.

3. The optical coupling module has a lens that optically couples with the optical element, The lens is housed in the second cavity. The optical module according to claim 1 or claim 2.

4. The optical coupling module comprises a holding portion for holding a plurality of optical fibers, and a mirror for converting the propagation direction of light emitted from the plurality of optical fibers, The holding portion and the mirror are located between the upper surface and the lower surface. The optical module according to claim 1 or claim 2.

5. A substrate having a glass cloth inside, composed of glass threads as the weft and warp threads, wherein the outer edge of the substrate, when viewed from the thickness direction, is rectangular in shape, defined by a pair of first sides along a predetermined direction and a pair of second sides along a direction perpendicular to the predetermined direction, The optical element mounted on the aforementioned substrate, An optical coupling module configured to optically couple with the aforementioned optical element, Equipped with, The weft thread, when viewed from the thickness direction of the substrate, is aligned with the first side surface. The warp threads are aligned with the second side surface when viewed from the thickness direction of the substrate. The substrate has a cavity formed therein that is recessed from the first main surface of the substrate toward the second main surface of the substrate, having a bottom, and at least a part of the optical coupling module is housed in the cavity. The side surface of the cavity includes an inclined region that, when viewed from the thickness direction of the substrate, is inclined with respect to the direction of extension of the weft threads and the direction of extension of the warp threads. The cavity comprises a first cavity and a second cavity having a smaller opening area than the first cavity, which includes a second bottom located closer to the second main surface than the first bottom of the first cavity. The optical coupling module has an upper surface and a lower surface that face each other in the thickness direction of the substrate, The distance from the first main surface to the first bottom in the thickness direction of the substrate is more than half the distance from the top surface to the bottom surface in the thickness direction of the substrate. Optical module.

6. The side surface of the second cavity includes the inclined region, The optical coupling module has a lens that optically couples with the optical element, The lens is housed in the second cavity. The optical module according to claim 5.

7. The aforementioned inclined region is a curved surface that is curved when viewed from the thickness direction of the substrate. The optical module according to claim 5 or claim 6.

8. When viewed from the thickness direction of the substrate, the outer edge of the cavity has an elliptical or sectoral shape defined by the side surface. The optical module according to claim 5 or claim 6.

9. When viewed from the thickness direction of the substrate, the outer edge of the cavity has a rhombic or triangular shape defined by the side surface. The optical module according to claim 5 or claim 6.

10. The optical coupling module comprises a holding portion for holding a plurality of optical fibers, and a mirror for converting the propagation direction of light emitted from the plurality of optical fibers, The holding portion and the mirror are located between the upper surface and the lower surface. The optical module according to claim 5 or claim 6.

11. When viewed from the thickness direction of the substrate, the angle between the inclined region and the direction of extension of the weft thread is 10° or more and 80° or less. When viewed from the thickness direction of the substrate, the angle between the inclined region and the direction of extension of the warp threads is 10° or more and 80° or less. The optical module according to claim 1 or claim 2.

12. The optical coupling module has a holding portion that holds the end of an optical fiber that is optically coupled to the optical element via the optical coupling module. The optical module according to claim 1 or claim 2.

13. The cavity has a through hole formed therein that penetrates from the bottom to the second main surface. The optical element is mounted on the second main surface such that, when viewed from above, the second main surface overlaps with the through hole. The optical module according to claim 1 or claim 2.

14. A substrate having a glass cloth inside, composed of glass threads as the weft and warp threads, wherein the outer edge of the substrate, when viewed from the thickness direction, is rectangular in shape, defined by a pair of first sides along a predetermined direction and a pair of second sides along a direction perpendicular to the predetermined direction, Multiple optical elements mounted on the aforementioned substrate, Multiple optical coupling modules configured to optically couple with each of the aforementioned multiple optical elements, Equipped with, The weft thread is inclined with respect to the first and second sides when viewed from the thickness direction of the substrate. The warp threads are inclined with respect to the first and second sides when viewed from the thickness direction of the substrate. The substrate has a plurality of cavities formed therein that are recessed from the first main surface of the substrate toward the second main surface of the substrate, each of which houses one of the plurality of optical coupling modules. Each of the sides of the plurality of cavities includes an inclined region that, when viewed from the thickness direction of the substrate, is inclined with respect to the direction of extension of the weft threads and the direction of extension of the warp threads. Each of the plurality of cavities comprises a first cavity and a second cavity having a smaller opening area than the first cavity, with the second bottom being located closer to the second main surface than the first bottom of the first cavity. Each of the aforementioned optical coupling modules has an upper surface and a lower surface that face each other in the thickness direction of the substrate, The distance from the first main surface to the first bottom in the thickness direction of the substrate is more than half the distance from the top surface to the bottom surface in the thickness direction of the substrate. Optical module.

15. Each of the plurality of optical coupling modules has a holding portion for holding a plurality of optical fibers and a mirror for changing the propagation direction of light emitted from the plurality of optical fibers, The holding portion and the mirror are located between the upper surface and the lower surface. The optical module according to claim 14.

16. The optical module according to claim 1 or claim 2, A fiber optic cable having at least one optical fiber, An optical connector cable in which the optical fiber cable is attached to the optical module such that the optical fiber is optically coupled to the optical element via the optical coupling module.

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