Method for manufacturing an optical coupler, optical coupler, photoelectric conversion circuit module, and optical transceiver

Abstract

This optical coupler manufacturing method comprises: a preparation step for preparing a translucent substrate (11) having a first main surface (SU11) and a second main surface (SU 12) which are arranged in a first direction (DIR1); a first coating step for coating the first main surface (SU11) with a first photosensitive glass paste (12) containing a first filler (P1); a masking step for disposing a gray scale mask (10), which is formed with a binary pattern, on the second main surface (SU12); an exposure step for exposing the first photosensitive glass paste (12) by irradiating the second main surface (SU12) with ultraviolet rays; a developing step for developing the first photosensitive glass paste (12) by removing the gray scale mask (10) from the second main surface (SU12); and a curing step for curing the first photosensitive glass paste (12) by removing the translucent substrate (11) from the developed first photosensitive glass paste (12). The maximum length (r1) of the first filler (P1) is longer than the wavelength of the ultraviolet rays.

Description

Technical Field

[0001] The present invention relates to a method for manufacturing an optical coupler, an optical coupler, a photoelectric conversion circuit module, and an optical transceiver.

Background Art

[0002] For example, the grayscale mask described in Patent Document 1 is used for purposes such as manufacturing a microlens. The grayscale mask described in Patent Document 1 is composed of a plurality of adjacent pixels. One pixel has at least one unit region. The unit region is composed of a first region that is a light-transmitting region that transmits light and a second region that is a light-blocking region that does not transmit light. The light transmittance of the unit region is determined according to the area ratio of the light-transmitting region and the light-blocking region.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the manufacture of an optical coupler such as a microlens, when the grayscale mask described in Patent Document 1 is used as a photomask, due to the periodic structure of the light-transmitting region and the light-blocking region, light diffracts during exposure. The diffracted light is irradiated at a high level in a direction other than the target direction. Therefore, the photosensitive material is not exposed as designed, and the processing accuracy may decrease.

[0005] Therefore, an object of the present invention is to provide a method for manufacturing an optical coupler, an optical coupler, a photoelectric conversion circuit module, and an optical transceiver that can suppress a decrease in processing accuracy.

Means for Solving the Problems

[0006] A method for manufacturing an optical coupler according to one embodiment of the present invention is: A preparation step of preparing a translucent substrate having a first main surface and a second main surface aligned in a first direction, A first coating step of applying a first photosensitive glass paste containing a first filler to the first main surface, A masking step involves placing a grayscale mask formed by a binary pattern onto the second main surface, An exposure step of irradiating the second main surface with ultraviolet light to expose the first photosensitive glass paste, A developing step in which the grayscale mask is removed from the second main surface and the first photosensitive glass paste is developed, A curing step is performed to remove the light-transmitting substrate from the developed first photosensitive glass paste and to cure the first photosensitive glass paste, It is equipped with, The longest length of the first filler is longer than the wavelength of ultraviolet light.

[0007] When the longest length of the first filler is longer than the wavelength of ultraviolet light, the ultraviolet light diffracted by the grayscale mask is scattered by the first filler. As a result, diffracted light is not irradiated at a high level in directions other than the target direction. Therefore, this embodiment can suppress a decrease in processing accuracy.

[0008] A method for manufacturing an optical coupler according to one embodiment of the present invention is: A translucent substrate having a first main surface and a second main surface aligned in a first direction, comprising a preparation step for preparing a translucent substrate containing a third filler, A first coating step of applying a first photosensitive glass paste to the first main surface, A masking step involves placing a grayscale mask formed by a binary pattern onto the second main surface, An exposure step of irradiating the second main surface with ultraviolet light to expose the first photosensitive glass paste, A developing step in which the grayscale mask is removed from the second main surface and the first photosensitive glass paste is developed, A curing step is performed to remove the light-transmitting substrate from the developed first photosensitive glass paste and to cure the first photosensitive glass paste, It is equipped with, The longest length of the third filler is longer than the wavelength of ultraviolet light.

[0009] Even when the longest length of the third filler is longer than the wavelength of ultraviolet light, the ultraviolet light diffracted by the grayscale mask is scattered by the third filler. As a result, diffracted light is not irradiated at a high level in directions other than the target direction. Therefore, this embodiment can also suppress a decrease in processing accuracy.

[0010] An optical coupler according to one embodiment of the present invention is A photocoupler comprising a first photosensitive glass paste containing a first filler, The longest length of the first filler is longer than the wavelength of ultraviolet light irradiated onto the grayscale mask, which is formed by a binary pattern.

[0011] An optical coupler according to one embodiment of the present invention is A first glass portion comprising a first glass and a first filler mixed within the first glass, A second glass portion that includes at least a second glass and is connected to the first glass portion, It is equipped with, The second glass portion contains a second filler mixed within the second glass, and the content of the second filler in the second glass portion is lower than the content of the first filler in the first glass portion. Alternatively, the second glass portion does not include the second filler.

[0012] In this embodiment, the second glass part has no filler or has a lower filler content than the first glass part. However, when the first glass part is irradiated with ultraviolet light, the first filler in the first glass part having a relatively high content diffuses the diffracted light generated during manufacturing. As a result, the diffracted light is not irradiated at a high level in a direction other than the target direction. Therefore, this embodiment can also suppress a decrease in processing accuracy.

[0013] An optical coupler according to one embodiment of the present invention is a first glass part, a transmission part connected to the first glass part, and includes: The first glass part includes glass and a first filler mixed in the glass. The transmission part includes a medium and a second filler mixed in the medium. The longest length of the second filler is different from the longest length of the first filler.

[0014] In this embodiment, ultraviolet light is irradiated onto the first glass part or the transmission part having the filler with the longest length among the first glass part and the transmission part to diffuse the diffracted light. As a result, the diffracted light is not irradiated at a high level in a direction other than the target direction. Therefore, this embodiment can also suppress a decrease in processing accuracy.

Advantages of the Invention

[0015] According to the method for manufacturing an optical coupler, the optical coupler, the photoelectric conversion circuit module, and the optical transceiver according to the present invention, it is possible to suppress a decrease in processing accuracy.

Brief Description of the Drawings

[0016] [Figure 1] FIG. 1 is a perspective view of the optical coupler 1. [Figure 2] FIG. 2 is a cross-sectional view of the optical coupler 1 and the optical fiber 5. [Figure 3] FIG. 3 is a plan view of the optical coupler 1 viewed in the first direction DIR1. [Figure 4] Figure 4 is a flowchart showing the method for manufacturing the optical coupler 1. [Figure 5] Figure 5 is a cross-sectional view of the optical coupler 1 during manufacturing. [Figure 6] Figure 6 shows the pixels 15 of the grayscale mask 10. [Figure 7] Figure 7 shows a pattern in which the pixels 15 of the grayscale mask 10 are arranged in order of aperture ratio. [Figure 8] Figure 8 shows an example of a grayscale mask 10 corresponding to the optical coupler 1. [Figure 9] Figure 9 shows the light intensity distribution of a comparative example in the exposure process. [Figure 10] Figure 10 shows the light intensity distribution in the exposure process according to the first embodiment. [Figure 11] Figure 11 is a perspective view of the translucent substrate 11. [Figure 12] Figure 12 is a cross-sectional view of the optical coupler 1b and the optical fiber 5. [Figure 13] Figure 13 is a flowchart showing the method for manufacturing the optical coupler 1b. [Figure 14] Figure 14 is a cross-sectional view of the optical coupler 1b during manufacturing. [Figure 15] Figure 15 is a cross-sectional view of the optical coupler 1c and the optical fiber 5. [Figure 16] Figure 16 is a cross-sectional view of the optical coupler 1c during manufacturing. [Figure 17] Figure 17 is a cross-sectional view of the optical coupler 1d and the optical fiber 5. [Figure 18] Figure 18 is a perspective view of the photoelectric conversion circuit module 50 and the optical fiber 5. [Figure 19] Figure 19 is a cross-sectional view AA of the photoelectric conversion circuit module 50 and the optical fiber 5. [Figure 20] Figure 20 is a perspective view of the photoelectric conversion circuit module 50a and the optical fiber 5. [Figure 21] Figure 21 is a perspective view of the optical transceiver 100 and the optical fiber 5. [Modes for carrying out the invention]

[0017] [First Embodiment] [Structure of photocoupler 1] The optical coupler 1 according to the first embodiment of the present invention will be described below with reference to the drawings. Figure 1 is a perspective view of the optical coupler 1. In Figure 1, only a representative first filler P1 among the multiple first fillers P1 is given a reference numeral. Figure 2 is a cross-sectional view of the optical coupler 1 and the optical fiber 5. In Figure 2, the second sidewall portion 22 and the third sidewall portion 23 are omitted. Figure 3 is a plan view of the optical coupler 1 as seen in the first direction DIR1.

[0018] In this specification, directions are defined as follows: As shown in Figure 1, the direction in which the bottom portion 24 and the reflecting portion 3 are aligned in this order is defined as the first direction DIR1. The direction in which the reflecting portion 3 and the optical fiber fixing portion 4 are aligned in this order is defined as the second direction DIR2. The direction in which the second sidewall portion 22 and the third sidewall portion 23 are aligned in this order is defined as the third direction DIR3. The first direction DIR1, the second direction DIR2, and the third direction DIR3 are orthogonal to each other. However, the first direction DIR1, the second direction DIR2, and the third direction DIR3 in this specification are directions defined for the convenience of explanation and do not necessarily coincide with the first direction DIR1, the second direction DIR2, and the third direction DIR3 when the optical coupler 1 is in use.

[0019] The optical coupler 1 is a device for changing the direction of propagation of light emitted from a photoelectric conversion circuit or the like and outputting it to an optical fiber, or changing the direction of propagation of light emitted from an optical fiber and outputting it to a photoelectric conversion circuit or the like. In this embodiment, the case in which the optical coupler 1 changes the direction of propagation of light L emitted from a photoelectric conversion circuit or the like from a first direction DIR1 to a second direction DIR2 and outputs it to an optical fiber 5 will be described. As shown in Figure 2, the optical coupler 1 has an input surface S11 into which light L is incident in the first direction DIR1 and an output surface S12 into which light L is output in the second direction DIR2. Note that when the optical coupler 1 changes the direction of propagation of light L emitted from the optical fiber 5 from the opposite direction of the second direction DIR2 to the opposite direction of the first direction DIR1 and outputs it to a photoelectric conversion circuit or the like, the input surface and the output surface may be swapped. Note that the optical coupler 1 is an example of the "optical coupler" of the present invention. The "optical coupler" of the present invention may be a focusing lens or a microlens array, etc. The structure of the optical coupler 1 will be described in detail below.

[0020] As shown in Figure 1, the optical coupler 1 comprises a holding part 2, a reflecting part 3, and an optical fiber fixing part 4. The optical coupler 1 is integrally molded from glass containing a filler. Furthermore, the optical coupler 1 is a single component. Here, a single component means a component that has a structure that cannot be separated without damage. Therefore, for example, a component in which two resin pieces are fixed together with screws is not a single component. Note that the optical coupler 1 does not have to be integrally molded from glass containing a filler. Also, the optical coupler 1 does not have to be a single component.

[0021] The photocoupler 1 is integrally molded from a material containing glass M1 and a plurality of first fillers P1 mixed within the glass M1. The glass is amorphous and exhibits a glass transition phenomenon. Examples of glass include simple oxide glasses such as SiO2, B2O3, P2O5, GeO2, and AS3O3; silicate glasses such as Li2O-SiO2, Na2O-SiO2, and K2O-SiO2; aluminosilicate glasses such as Na2O-Al2O3-SiO2 and CaO-Al2O3-SiO2; borate glasses such as Li2O-B2O3 and Na2O-B2O3; aluminoborate glasses such as CaO-Al2O3-B2O3; and borosilicate glasses such as Na2O-Al2O3-B2O3-SiO2.

[0022] The multiple first fillers P1 are metal oxide particles such as crystalline silica, amorphous silica, alumina, magnesium oxide, titanium oxide, barium titanate, calcium titanate, or organic particles such as graphite. The first fillers P1 include fillers having an aspherical shape. The multiple first fillers P1 are dispersed throughout the glass M1. Note that the first fillers P1 do not necessarily include fillers having an aspherical shape. Furthermore, the multiple first fillers P1 may be uniformly dispersed throughout the glass M1, or they may be unevenly dispersed throughout the glass M1.

[0023] Let r1 be the longest length of each of the multiple first fillers P1. If each of the multiple first fillers P1 has a spherical shape, the longest length r1 of each of the multiple first fillers P1 is the diameter of the sphere. If each of the multiple first fillers P1 has an ellipsoid shape, the longest length r1 of each of the multiple first fillers P1 is the length along the major axis of the ellipsoid. Thus, the longest length r1 of each of the multiple first fillers P1 is the length in the longitudinal direction of the longest portion of each of the multiple first fillers P1. In this embodiment, the maximum value of the longest length r1 of each of the multiple first fillers P1 is longer than the wavelength λ of ultraviolet (UV), which will be described later. That is, there exists a first filler P1 having a longest length r1 that is longer than the wavelength λ of ultraviolet (UV).

[0024] The holding part 2 holds the reflective part 3 and the optical fiber fixing part 4, respectively. The holding part 2 is connected to the reflective part 3 and the optical fiber fixing part 4. The holding part 2 includes a first side wall portion 21, a second side wall portion 22, a third side wall portion 23, and a bottom portion 24. However, the holding part 2 does not necessarily have to include the first side wall portion 21, the second side wall portion 22, and the third side wall portion 23.

[0025] The first side wall portion 21 is connected to the second side wall portion 22, the third side wall portion 23, and the bottom portion 24, respectively. More specifically, the first side wall portion 21 has a shape that extends in the third direction DIR3. In this embodiment, the first side wall portion 21 has a plate shape. The end face of the first side wall portion 21 with respect to the third direction DIR3 is connected to the third side wall portion 23. The end face of the first side wall portion 21 in the opposite direction to the third direction DIR3 is connected to the second side wall portion 22. The end face of the first side wall portion 21 in the opposite direction to the first direction DIR1 is connected to the bottom portion 24. Note that the first side wall portion 21 does not necessarily have to have a plate shape.

[0026] The second side wall portion 22 is connected to the first side wall portion 21, the bottom portion 24, the reflecting portion 3, and the optical fiber fixing portion 4. More specifically, the second side wall portion 22 has a shape that extends in the second direction DIR2. In this embodiment, the second side wall portion 22 has a plate shape. A portion of the end face of the second side wall portion 22 with respect to the third direction DIR3 is connected to the end face of the first side wall portion 21 in the opposite direction to the third direction DIR3, the reflecting portion 3, and the optical fiber fixing portion 4. The end face of the second side wall portion 22 in the opposite direction to the first direction DIR1 is connected to the bottom portion 24. Note that the second side wall portion 22 does not necessarily have to have a plate shape.

[0027] The third side wall portion 23 is connected to the first side wall portion 21, the bottom portion 24, the reflecting portion 3, and the optical fiber fixing portion 4. More specifically, the third side wall portion 23 has a shape that extends in the second direction DIR2. In this embodiment, the third side wall portion 23 has a plate shape. A portion of the end face of the third side wall portion 23 in the direction opposite to the third direction DIR3 is connected to the end face of the first side wall portion 21 in the direction opposite to the third direction DIR3, the reflecting portion 3, and the optical fiber fixing portion 4. The end face of the third side wall portion 23 in the direction opposite to the first direction DIR1 is connected to the bottom portion 24. Note that the third side wall portion 23 does not necessarily have to have a plate shape.

[0028] The bottom portion 24 is connected to the first side wall portion 21, the second side wall portion 22, the third side wall portion 23, the reflecting portion 3, and the optical fiber fixing portion 4. More specifically, the bottom portion 24 has a plate shape. In this embodiment, the bottom portion 24 has a rectangular shape when viewed in the first direction DIR1. A portion of the end face of the bottom portion 24 with respect to the first direction DIR1 is connected to the end face of the first side wall portion 21 in the opposite direction of the first direction DIR1, the end face of the second side wall portion 22 in the opposite direction of the first direction DIR1, the end face of the third side wall portion 23 in the opposite direction of the first direction DIR1, the reflecting portion 3, and the optical fiber fixing portion 4. Note that the bottom portion 24 does not have to have a rectangular shape when viewed in the first direction DIR1.

[0029] As shown in Figure 2, the light L enters the optical coupler 1 from the end face S1 of the bottom 24 in the opposite direction to the first direction DIR1. Therefore, the end face S1 of the bottom 24 in the opposite direction to the first direction DIR1 includes the incident surface S11 of the optical coupler 1. The light L that enters the bottom 24 from the end face S1 in the opposite direction to the first direction DIR1 passes through the interior of the bottom 24 and enters the reflecting section 3.

[0030] Here, as shown in Figure 3, on the end face S1 of the bottom 24 in the direction opposite to the first direction DIR1, the region that overlaps with the reflecting portion 3 when viewed in the direction DIR1 is defined as region A1. Also, on the end face S1 of the bottom 24 in the direction opposite to the first direction DIR1, the region that does not overlap with the reflecting portion 3 when viewed in the direction DIR1 is defined as region A2. The end face S1 of the bottom 24 in the direction opposite to the first direction DIR1 includes both region A1 and region A2. Light L is incident on the optical coupler 1 from region A1 of the bottom 24. Therefore, region A1 is the incident surface S11. Region A2 is the mounting surface S21 for mounting the optical coupler 1 on a substrate when the optical coupler 1 is incorporated into a photoelectric conversion circuit module or the like. The end face S1 of the bottom 24 in the direction opposite to the first direction DIR1 includes the incident surface S11 and the mounting surface S21. In other words, the mounting surface S21 is in the same plane as the incident surface S11.

[0031] As shown in Figure 1, the reflective section 3 is connected to the second side wall 22, the third side wall 23, and the bottom 24, respectively. As shown in Figure 2, the reflective section 3 changes the direction of light L incident from the incident surface S11 from the first direction DIR1 to the second direction DIR2, and emits it out into one of the five optical fibers 5. The reflective section 3 includes a prism section 31 and five condensing lens sections 32. Note that the number of condensing lens sections 32 is not limited to five. Also, the reflective section 3 does not necessarily have to include condensing lens sections 32.

[0032] The prism section 31 is connected to the second side wall section 22, the third side wall section 23, and the bottom section 24, respectively. More specifically, in this embodiment, the prism section 31 has a right-angled isosceles triangular prism shape extending in the third direction DIR3. The prism section 31 has a prism section incident surface S2, a prism section reflection surface S3, a prism section exit surface S4, an end face with respect to the third direction DIR3, and an end face with respect to the opposite direction of the third direction DIR3. The end face of the prism section 31 with respect to the third direction DIR3 is connected to the third side wall section 23. The end face of the prism section 31 with respect to the opposite direction of the third direction DIR3 is connected to the second side wall section 22. Note that the prism section 31 does not necessarily have to have a right-angled isosceles triangular prism shape.

[0033] The prism section's incident surface S2 is the end face of the prism section 31 in the opposite direction to the first direction DIR1. The prism section's incident surface S2 is connected to the bottom section 24. Light L that has passed through the inside of the bottom section 24 enters the prism section 31 from the prism section's incident surface S2. Light L that has entered the prism section 31 from the prism section's incident surface S2 passes through the inside of the prism section 31.

[0034] The prism reflective surface S3 is at a 45-degree angle with the prism incident surface S2 and the prism exit surface S4 when viewed in the third direction DIR3. The end of the prism reflective surface S3 with respect to the first direction DIR1 is located in the second direction DIR2 from the end of the prism reflective surface S3 in the opposite direction to the first direction DIR1. The prism reflective surface S3 reflects the light L that has passed through the interior of the prism 31. As a result, the prism reflective surface S3 changes the direction of propagation of the light L from the first direction DIR1 to the second direction DIR2.

[0035] The five condensing lens sections 32 are provided on the reflective surface S3 of the prism section. The five condensing lens sections 32 are aligned in the third direction DIR3. The surface of the condensing lens sections 32 is aspherical. The condensing lens sections 32 pass through the interior of the prism section 31 and reflect light L whose direction of propagation vector contains a component of the first direction DIR1. As a result, the condensing lens sections 32 change the direction of propagation of light L from a direction containing a component of the first direction DIR1 to the second direction DIR2.

[0036] The prism section exit surface S4 is the end face of the prism section 31 with respect to the first direction DIR1. The prism section exit surface S4 is perpendicular to the prism section incident surface S2. The prism section exit surface S4 emits light L that has been reflected by the prism section reflecting surface S3 or the condensing lens section 32 and has passed through the interior of the prism section 31. The light L emitted from the prism section exit surface S4 travels in the first direction DIR1. The prism section exit surface S4 is the exit surface S12 of the optical coupler 1.

[0037] The optical fiber fixing section 4 fixes each of the five optical fibers 5. The optical fiber fixing section 4 is connected to the second side wall section 22, the third side wall section 23, and the bottom section 24, respectively. More specifically, the optical fiber fixing section 4 has a plate shape extending in the third direction DIR3. In this embodiment, the end face of the optical fiber fixing section 4 in the third direction DIR3 is connected to the third side wall section 23. The end face of the optical fiber fixing section 4 in the opposite direction to the third direction DIR3 is connected to the second side wall section 22. The end face of the optical fiber fixing section 4 in the opposite direction to the first direction DIR1 is connected to the bottom section 24.

[0038] As shown in Figure 1, the end face of the optical fiber fixing section 4 in the first direction DIR1 is provided with five V-shaped grooves G when viewed in the second direction DIR2. Each of the five grooves G has a shape that extends in the second direction DIR2. The five grooves G are aligned in the third direction DIR3. Each of the five optical fibers 5 is fixed to each of the five grooves G, as shown in Figure 2. The five optical fibers 5 are aligned in the third direction DIR3. Each of the five optical fibers 5 and the five focusing lens sections 32 are aligned in the second direction DIR2 when viewed in the first direction DIR1. Note that the end face of the optical fiber fixing section 4 in the first direction DIR1 does not necessarily have grooves G. Also, each of the five grooves G may have a U-shape when viewed in the second direction DIR2. Furthermore, the number of grooves G is not limited to five.

[0039] Each of the five optical fibers 5 has a shape that extends in the second direction DIR2. The end face of each of the five optical fibers 5 in the direction opposite to the second direction DIR2 faces the direction opposite to the second direction DIR2. The end face of each of the five optical fibers 5 in the direction opposite to the second direction DIR2 faces the prism exit surface S4 at a distance. As a result, the light L emitted from the prism exit surface S4 is incident on one of the five optical fibers 5.

[0040] [Manufacturing method for the optical coupler 1] Next, the manufacturing method of the optical coupler 1 will be described with reference to the drawings. Figure 4 is a flowchart of the manufacturing method of the optical coupler 1. Figure 5 is a cross-sectional view of the optical coupler 1 during manufacturing. Note that the second side wall portion 22 and the third side wall portion 23 are omitted in Figure 5. Figure 6 is a diagram showing the pixels 15 of the grayscale mask 10. Figure 7 is a diagram showing a pattern in which the pixels 15 of the grayscale mask 10 are arranged in order of aperture ratio. Figure 8 is an example of a grayscale mask 10 corresponding to the optical coupler 1.

[0041] First, as shown in Figure 5, a translucent substrate 11 having a first main surface SU11 and a second main surface SU12 aligned in the first direction DIR1 is prepared (preparation step, Figure 4: step ST1). The first main surface SU11 is located in the first direction DIR1 relative to the second main surface SU12. The translucent substrate 11 has a plate shape.

[0042] Next, the first photosensitive glass paste 12 is applied to the first main surface SU 11 of the translucent substrate 11 (first application step, Figure 4: step ST2). In this embodiment, the first photosensitive glass paste 12 is negative type. In the development step described later, the solubility of the exposed portion in the developer decreases. As a result, the exposed portion of the first photosensitive glass paste 12 remains. The first photosensitive glass paste 12 may also be positive type. In this case, in the development step described later, the solubility of the exposed portion in the developer increases. As a result, the unexposed portion of the first photosensitive glass paste 12 remains. The first photosensitive glass paste 12 includes glass M1 and a plurality of first fillers P1 mixed into the glass M1. In addition to glass M1 and the plurality of first fillers P1 mixed into the glass M1, the first photosensitive glass paste 12 may also include additives such as dispersants and light absorbers.

[0043] Next, a grayscale mask 10 is placed on the second main surface SU12 of the translucent substrate 11 (masking step, Figure 4: step ST3). The grayscale mask 10 is formed with a binary pattern. The grayscale mask 10 adjusts the light transmittance by controlling the aperture ratio. The grayscale mask 10 will be described in detail below.

[0044] As shown in Figure 6, the grayscale mask 10 has a configuration in which multiple pixels 15 are arranged adjacent to each other. Each pixel 15 has a unit region 16 and a runner region 17. The unit region 16 is square when viewed in the first direction DIR1. Furthermore, the unit region 16 is divided into four square-shaped sections A11, A12, A21, and A22. The runner region 17 is arranged around the unit region 16 when viewed in the first direction DIR1. The runner region 17 is a light-blocking region b that does not transmit light.

[0045] The unit region 16 is composed of an open (light-transmitting) light-transmitting region a and an closed (light-blocking) light-blocking region b. The aperture ratio (light transmittance) of the unit region 16 changes as the area ratio of the light-transmitting region a to the light-blocking region b changes.

[0046] For example, if all four square-shaped sections A11, A12, A21, and A22 are open, the aperture ratio of the unit region 16 is 100%. Also, if two square-shaped sections A12 and A21 are open, and two square-shaped sections A11 and A22 are not open, the area ratio of the light-transmitting region a to the light-shielding region b is 1:1, and the aperture ratio (light transmittance) of the unit region 16 is 50%. Furthermore, if all four square-shaped sections A11, A12, A21, and A22 are not open, the aperture ratio of the unit region 16 is 0%.

[0047] As shown in Figure 7, when unit regions 16 with aperture ratios from 0% to 100% in the grayscale mask 10 are arranged in this order in the second direction DIR2, the pattern of the grayscale mask 10 becomes a gradient. In Figure 7, unit regions 16 with aperture ratios differing by 10% are arranged in order, but by increasing the resolution of the aperture ratio, for example by arranging unit regions 16 with aperture ratios differing by 0.1%, the continuity of the light transmittance can be maintained. In this way, the grayscale mask 10 adjusts the light transmittance by controlling the aperture ratio.

[0048] As shown in Figure 8, the optical coupler 1 can be manufactured using the grayscale mask 10 by increasing the aperture ratio of the grayscale mask 10 corresponding to the first side wall portion 21, the second side wall portion 22, and the third side wall portion 23, and decreasing the aperture ratio of the grayscale mask 10 corresponding to the groove G.

[0049] Next, as shown in Figure 5, the second main surface SU12 of the translucent substrate 11 is irradiated with ultraviolet UV light to expose the first photosensitive glass paste 12 (exposure step, Figure 4: step ST4). The wavelength λ of ultraviolet UV light is longer than 10 nm and shorter than 380 nm. The exposure step causes the first photosensitive glass paste 12 to become photosensitive. In this embodiment, as described above, the maximum value of the longest length r1 of each of the multiple first fillers P1 is longer than the wavelength λ of ultraviolet UV light.

[0050] Next, the grayscale mask 10 is removed from the second main surface SU 12 of the translucent substrate 11, and the first photosensitive glass paste 12 is developed (development step, Figure 4: step ST5). More specifically, the first photosensitive glass paste 12 and the translucent substrate 11 are immersed in a developer solution. The development step removes the unexposed portion of the first photosensitive glass paste 12, leaving the exposed portion intact. After development, the first photosensitive glass paste 12 and the translucent substrate 11 are washed and dried.

[0051] Finally, the translucent substrate 11 is removed from the developed first photosensitive glass paste 12, and the first photosensitive glass paste 12 is cured (curing step, Figure 4: step ST6). More specifically, the first photosensitive glass paste 12 is fired and cured. After these steps, the photocoupler 1 is completed. Alternatively, as shown in Figure 5, grayscale masks 10 corresponding to multiple photocouplers 1 may be placed on the second main surface SU 12 of the translucent substrate 11, and after the first photosensitive glass paste 12 has cured, the cured first photosensitive glass paste 12 may be cut to complete multiple photocouplers 1.

[0052] [effect] The manufacturing method of the optical coupler 1 can suppress a decrease in processing accuracy. As a comparative example, a manufacturing method of an optical coupler without fillers will be described with reference to the drawings. Figure 9 shows the light intensity distribution of the comparative example in the exposure process. Figure 10 shows the light intensity distribution of the first embodiment in the exposure process. In Figures 9 and 10, ultraviolet (UV) light is laser light. Also, the beam diameter of the ultraviolet (UV) light is sufficiently small compared to the light transmission region a.

[0053] During the exposure process, ultraviolet (UV) light is diffracted by the periodic structure of the light-transmitting region a and light-blocking region b of the grayscale mask 10. If the first photosensitive glass paste 12 does not contain filler, as shown in Figure 9, high levels of light are distributed not only at position x1 in the second direction DIR2 of ultraviolet (UV) light. Therefore, high levels of ultraviolet (UV) light are also exposed to parts of the first photosensitive glass paste 12 other than position x1. In this embodiment, the first photosensitive glass paste 12 is negative type. Therefore, during the development process, parts of the first photosensitive glass paste 12 other than position x1 are more likely to remain. Thus, light distributed other than position x1 causes a decrease in processing accuracy.

[0054] Therefore, according to the manufacturing method of the photocoupler 1, the first photosensitive glass paste 12 contains a first filler P1. The longest length r1 of the first filler P1 is longer than the wavelength λ of ultraviolet (UV). As a result, the ultraviolet (UV) light diffracted by the periodic structure of the light-transmitting region a and light-blocking region b of the grayscale mask 10 is scattered by the first filler P1. Consequently, the light intensity distribution of ultraviolet (UV) light becomes a normal distribution with the strongest distribution at position x1, and the light intensity I(x) distributed at positions other than x1 becomes smaller than in the comparative example, as shown in Figure 10, preventing high levels of ultraviolet (UV) light from being irradiated at positions other than x1. Therefore, in the development process, it becomes less likely that portions of the first photosensitive glass paste 12 other than position x1 will remain. As a result, the manufacturing method of the photocoupler 1 can suppress a decrease in processing accuracy.

[0055] Furthermore, if the longest length r1 of the first filler P1 is less than or equal to the wavelength λ of ultraviolet (UV), the scattering of ultraviolet (UV) light is suppressed. Therefore, when using a grayscale mask 10 formed with a binary pattern, the longest length r1 of the first filler P1 is longer than the wavelength λ of ultraviolet (UV) light, which causes scattering of ultraviolet (UV) light and reduces the light intensity I(x) distributed at positions other than x1 in the second direction DIR2 of ultraviolet (UV) light.

[0056] Furthermore, according to the manufacturing method of the photocoupler 1, the content of the first filler P1 in the first photosensitive glass paste 12 can be reduced. More specifically, the first filler P1 includes fillers having a non-spherical shape. This allows for greater scattering of ultraviolet (UV) rays compared to the case where the first filler P1 contains only spherical fillers. As a result, according to the manufacturing method of the photocoupler 1, the content of the first filler P1 in the first photosensitive glass paste 12 can be reduced.

[0057] [First variation] [Structure of photocoupler 1a] The following describes an optical coupler 1a according to the first modified example of the present invention. Note that only the parts of the structure of the optical coupler 1a according to the first modified example that differ from the structure of the optical coupler 1 according to the first embodiment will be described, and the rest will be omitted.

[0058] In this modified example, the longest length r1 of each of the multiple first fillers P1 is less than the wavelength λ of ultraviolet light (UV). However, in this modified example, the longest length r1 of each of the multiple first fillers P1 may be greater than or equal to the wavelength λ of ultraviolet light (UV). Furthermore, in this modified example, the photocoupler 1a may not contain any first fillers P1. In this modified example, the photocoupler 1a corresponds to the "first glass portion" of the present invention.

[0059] [Manufacturing method for optical coupler 1a] Next, a method for manufacturing the optical coupler 1a according to the first modified example of the present invention will be described with reference to the drawings. Figure 11 is a perspective view of the translucent substrate 11. In Figure 11, only a representative third filler P3 among the multiple third fillers P3 is given a reference numeral. Regarding the method for manufacturing the optical coupler 1a according to the first modified example, only the parts that differ from the method for manufacturing the optical coupler 1 according to the first embodiment will be described, and the rest will be omitted.

[0060] The translucent substrate 11 includes a medium M2 and a plurality of third fillers P3 mixed within the medium M2. The medium M2 is, for example, a resin. The medium M2 may also be glass or the like.

[0061] The multiple third fillers P3 are metal oxide particles such as crystalline silica, amorphous silica, alumina, magnesium oxide, titanium oxide, barium titanate, calcium titanate, or organic particles such as graphite. The third fillers P3 include fillers with an aspherical shape. The multiple third fillers P3 are dispersed throughout the medium M2. Note that the third fillers P3 do not necessarily include fillers with an aspherical shape. Furthermore, the multiple third fillers P3 may be uniformly dispersed throughout the medium M2, or they may be unevenly dispersed throughout the medium M2.

[0062] Let r3 be the longest length of each of the multiple third fillers P3. If each of the multiple third fillers P3 has a spherical shape, the longest length r3 of each of the multiple third fillers P3 is the diameter of the sphere. If each of the multiple third fillers P3 has an ellipsoid shape, the longest length r3 of each of the multiple third fillers P3 is the length along the major axis of the ellipsoid. Thus, the longest length r3 of each of the multiple third fillers P3 is the length in the longitudinal direction of the longest part of each of the multiple third fillers P3. In this modified example, the maximum value of the longest length r3 of each of the multiple third fillers P3 is longer than the wavelength λ of ultraviolet (UV). Therefore, the maximum value of the longest length r3 of each of the multiple third fillers P3 is longer than the maximum value of the longest length r1 of each of the multiple first fillers P1. There exists a third filler P3 having a longest length r3 that is longer than the maximum value of the longest length r1 of the first filler P1.

[0063] In this modified example, it is not necessary to remove the translucent substrate 11 from the developed first photosensitive glass paste 12 during the curing process. That is, the translucent substrate 11 may be connected to the photocoupler 1a. In this case, the translucent substrate 11 corresponds to the "transmissive portion" of the present invention.

[0064] The manufacturing method for the photocoupler 1a described above also produces the same effects as the manufacturing method for the photocoupler 1. Furthermore, the manufacturing method for the photocoupler 1a allows for a reduction in the content of the first filler P1 in the first photosensitive glass paste 12. More specifically, the longest length r3 of the third filler P3 contained in the translucent substrate 11 is longer than the wavelength λ of ultraviolet (UV). As a result, the ultraviolet (UV) light diffracted by the periodic structure of the light-transmitting region a and light-shielding region b of the grayscale mask 10 is scattered by the third filler P3 contained in the translucent substrate 11. Consequently, the light intensity distribution of ultraviolet (UV) light becomes a normal distribution with the strongest distribution at position x1, and the light intensity I(x) distributed at positions other than x1 becomes smaller than in the comparative example, preventing high levels of ultraviolet (UV) light from being irradiated at positions other than x1. Therefore, in the development process, it becomes less likely that portions of the first photosensitive glass paste 12 other than position x1 will remain. This makes it possible to suppress a decrease in processing accuracy even when the content of the first filler P1 contained in the first photosensitive glass paste 12 is reduced. As a result, the method for manufacturing the photocoupler 1a makes it possible to reduce the content of the first filler P1 in the first photosensitive glass paste 12.

[0065] Furthermore, the manufacturing method for the optical coupler 1a can improve the processing accuracy of the optical coupler 1a. More specifically, the third filler P3 includes fillers having a non-spherical shape. This allows for greater scattering of ultraviolet (UV) light compared to the case where the third filler P3 contains only spherical fillers. Therefore, the manufacturing method for the optical coupler 1a can reduce the content of the third filler P3 in the translucent substrate 11. As a result, the manufacturing method for the optical coupler 1a can improve the processing accuracy of the optical coupler 1a.

[0066] [Second variation] [Structure of photocoupler 1b] Below, an optical coupler 1b according to a second modification of the present invention will be described with reference to the drawings. Figure 12 is a cross-sectional view of the optical coupler 1b and the optical fiber 5. Note that the second sidewall portion 22 and the third sidewall portion 23 are omitted in Figure 12. Regarding the structure of the optical coupler 1b according to the second modification, only the parts that differ from the structure of the optical coupler 1 according to the first embodiment will be described, and the rest will be omitted.

[0067] In this modified example, multiple first fillers P1 are included only in the bottom portion 24, while fillers are not included in the first sidewall portion 21, the second sidewall portion 22, the third sidewall portion 23, the reflecting portion 3, and the optical fiber fixing portion 4. Alternatively, multiple first fillers P1 may be included only in the end face S1 of the bottom portion 24 in the direction opposite to the first direction DIR1, and fillers may not be included in any other part of the bottom portion 24. In this modified example, the bottom portion 24 corresponds to the "first glass portion" of the present invention. Each of the first sidewall portion 21, the second sidewall portion 22, the third sidewall portion 23, the reflecting portion 3, and the optical fiber fixing portion 4 corresponds to the "second glass portion" or "transmissive portion" of the present invention. The "second glass portion" of the present invention includes at least glass.

[0068] [Manufacturing method for the optical coupler 1b] Next, a method for manufacturing the optical coupler 1b according to a second modified example of the present invention will be described with reference to the drawings. Figure 13 is a flowchart showing the method for manufacturing the optical coupler 1b. Figure 14 is a cross-sectional view of the optical coupler 1b during manufacturing. Note that the second side wall portion 22 and the third side wall portion 23 are omitted in Figure 14. Regarding the method for manufacturing the optical coupler 1b according to the second modified example, only the parts that differ from the method for manufacturing the optical coupler 1 according to the first embodiment will be described, and the rest will be omitted.

[0069] In this modified example, after the first coating step, a second photosensitive glass paste 13 without filler is applied to the first photosensitive glass paste 12 (second coating step, Figure 13: step ST21). In this modified example, the second photosensitive glass paste 13 is negative type. If the first photosensitive glass paste 12 is positive type, the second photosensitive glass paste 13 may also be positive type. In addition to glass, the second photosensitive glass paste 13 may contain additives such as dispersants and light absorbers. The second coating step may be performed after the masking step. The second coating step may be performed between the first coating step and the exposure step.

[0070] In the exposure process, ultraviolet light (UV) is irradiated onto the second main surface SU12 of the translucent substrate 11 to expose the first photosensitive glass paste 12 and the second photosensitive glass paste 13 (Figure 13: Step ST4). As a result of the exposure process, the first photosensitive glass paste 12 and the second photosensitive glass paste 13 are exposed to light.

[0071] In the developing process, the grayscale mask 10 is removed from the second main surface SU 12 of the translucent substrate 11, and the first photosensitive glass paste 12 and the second photosensitive glass paste 13 are developed (Figure 13: Step ST5). More specifically, the first photosensitive glass paste 12, the second photosensitive glass paste 13 and the translucent substrate 11 are immersed in a developer solution. Through the developing process, the exposed portions of the first photosensitive glass paste 12 and the second photosensitive glass paste 13 remain, while the unexposed portions are removed. After development, the first photosensitive glass paste 12, the second photosensitive glass paste 13 and the translucent substrate 11 are washed and dried.

[0072] In the curing process, the translucent substrate 11 is removed from the developed first photosensitive glass paste 12, and the first photosensitive glass paste 12 and the second photosensitive glass paste 13 are cured (Figure 13: Step ST6). More specifically, the first photosensitive glass paste 12 and the second photosensitive glass paste 13 are fired to cure them.

[0073] The manufacturing method of the photocoupler 1b described above also produces the same effects as the manufacturing method of the photocoupler 1. More specifically, in the exposure process, ultraviolet UV light is irradiated onto the second main surface SU12 of the translucent substrate 11. Therefore, because the longest length r1 of the first filler P1 contained in the first photosensitive glass paste 12 applied to the first main surface SU11 of the translucent substrate 11 is longer than the wavelength λ of ultraviolet UV light, the ultraviolet UV light diffracted by the periodic structure of the light transmission region a and light shielding region b of the grayscale mask 10 is scattered by the first filler P1. As a result, the light intensity distribution of ultraviolet UV light becomes a normal distribution with the strongest distribution at position x1, and the light intensity I(x) distributed at positions other than x1 becomes smaller than in the comparative example, so that high levels of ultraviolet UV light are not irradiated at positions other than x1. Therefore, in the development process, portions of the first photosensitive glass paste 12 and the second photosensitive glass paste 13 other than position x1 are less likely to remain. Therefore, even if the second photosensitive glass paste 13 applied to the first photosensitive glass paste 12 does not contain fillers, the same effect as the manufacturing method of the photocoupler 1 is achieved.

[0074] Furthermore, according to the method for manufacturing the photocoupler 1b, the second photosensitive glass paste 13 does not contain fillers. Therefore, the method for manufacturing the photocoupler 1b can improve the shape accuracy of the photocoupler 1b.

[0075] [Third variation] [Structure of optical coupler 1c] The optical coupler 1c according to a third modified example of the present invention will be described below. Figure 15 is a cross-sectional view of the optical coupler 1c and the optical fiber 5. Note that the second sidewall portion 22 and the third sidewall portion 23 are omitted in Figure 15. Regarding the structure of the optical coupler 1c according to the third modified example, only the parts that differ from the structure of the optical coupler 1b according to the second modified example will be described, and the rest will be omitted.

[0076] In this modified example, the bottom portion 24 includes glass M1 and a plurality of first fillers P1 mixed within the glass M1. Each of the first sidewall portion 21, second sidewall portion 22, third sidewall portion 23, reflective portion 3, and optical fiber fixing portion 4 includes glass M1 and a plurality of second fillers P2 mixed within the glass M1. The content of the second fillers P2 in each of the first sidewall portion 21, second sidewall portion 22, third sidewall portion 23, reflective portion 3, and optical fiber fixing portion 4 is lower than the content of the first fillers P1 in the bottom portion 24. Note that the content of the second fillers P2 in the bottom portion 24 other than the end face S1 in the opposite direction of the first direction DIR1 may be lower than the content of the first fillers P1 in the end face S1 in the opposite direction of the first direction DIR1.

[0077] The multiple second fillers P2 are metal oxide particles such as crystalline silica, amorphous silica, alumina, magnesium oxide, titanium oxide, barium titanate, calcium titanate, or organic particles such as graphite. The second fillers P2 include fillers with an aspherical shape. The multiple second fillers P2 are dispersed throughout the glass M1. Note that the second fillers P2 do not necessarily include fillers with an aspherical shape. Furthermore, the multiple second fillers P2 may be uniformly dispersed throughout the glass M1, or they may be unevenly dispersed throughout the glass M1.

[0078] [Manufacturing method for optical coupler 1c] Next, a method for manufacturing the optical coupler 1c according to a third modified example of the present invention will be described with reference to the drawings. Figure 16 is a cross-sectional view of the optical coupler 1c during manufacturing. Note that the second side wall portion 22 and the third side wall portion 23 are omitted in Figure 16. Furthermore, only the parts of the method for manufacturing the optical coupler 1c according to the third modified example that differ from the method for manufacturing the optical coupler 1b according to the second modified example will be described, and the rest will be omitted.

[0079] In this modified example, after the first coating step, a second photosensitive glass paste 13 containing a second filler P2 is applied to the first photosensitive glass paste 12 (second coating step). The content of the second filler P2 in the second photosensitive glass paste 13 is lower than the content of the first filler P1 in the first photosensitive glass paste 12. The second coating step may be performed after the masking step. The second coating step may be performed between the first coating step and the exposure step.

[0080] The method for manufacturing the photocoupler 1c described above also produces the same effects as the method for manufacturing the photocoupler 1b. More specifically, for the same reasons as in the method for manufacturing the photocoupler 1b, even if the content of the second filler P2 in the second photosensitive glass paste 13 applied to the first photosensitive glass paste 12 is lower than the content of the first filler P1 in the first photosensitive glass paste 12, the method produces the same effects as the method for manufacturing the photocoupler 1b.

[0081] Furthermore, according to the manufacturing method of the photocoupler 1c, the content of the second filler P2 in the second photosensitive glass paste 13 is lower than the content of the first filler P1 in the first photosensitive glass paste 12. Therefore, the manufacturing method of the photocoupler 1c can improve the shape accuracy of the photocoupler 1c.

[0082] [Fourth variation] [Structure of photocoupler 1d] The optical coupler 1d according to the fourth modification of the present invention will be described below with reference to the drawings. Figure 17 is a cross-sectional view of the optical coupler 1d and the optical fiber 5. Note that the second sidewall portion 22 and the third sidewall portion 23 are omitted in Figure 17. Regarding the structure of the optical coupler 1d according to the fourth modification, only the parts that differ from the structure of the optical coupler 1c according to the third modification will be described, and the rest will be omitted.

[0083] Let r2 be the longest length of each of the multiple second fillers P2. If each of the multiple second fillers P2 has a spherical shape, the longest length r2 of each of the multiple second fillers P2 is the diameter of the sphere. If each of the multiple second fillers P2 has an ellipsoid shape, the longest length r2 of each of the multiple second fillers P2 is the length along the major axis of the ellipsoid. Thus, the longest length r2 of each of the multiple second fillers P2 is the length in the longitudinal direction of the longest portion of each of the multiple second fillers P2. In this modified example, the maximum value of the longest length r2 of each of the multiple second fillers P2 is greater than 0 and less than or equal to the wavelength λ of ultraviolet light (UV). Therefore, the maximum value of the longest length r2 of each of the multiple second fillers P2 is shorter than the maximum value of the longest length r1 of each of the multiple first fillers P1. There exists a first filler P1 that has a longest length r1 that is longer than the maximum value of the longest length r2 of the second filler P2. The maximum value of the longest length r2 of each of the multiple second fillers P2 is different from the maximum value of the longest length r1 of each of the multiple first fillers P1.

[0084] [Manufacturing method for photocoupler 1d] The following describes the optical coupler 1d according to the fourth modified example of the present invention. Note that only the parts of the manufacturing method for the optical coupler 1d according to the fourth modified example that differ from the manufacturing method for the optical coupler 1c according to the third modified example will be described, and the rest will be omitted.

[0085] In this modified example, the maximum value of the longest length r2 of each of the multiple second fillers P2 contained in the second photosensitive glass paste 13 is greater than 0 and less than or equal to the wavelength λ of ultraviolet UV.

[0086] The method for manufacturing the photocoupler 1d described above also produces the same effects as the method for manufacturing the photocoupler 1c. More specifically, for the same reasons as the method for manufacturing the photocoupler 1c, even if the longest length r2 of the second filler P2 contained in the second photosensitive glass paste 13 applied to the first photosensitive glass paste 12 is longer than 0 and less than or equal to the wavelength λ of ultraviolet UV, the method produces the same effects as the method for manufacturing the photocoupler 1c.

[0087] Furthermore, according to the manufacturing method of the photocoupler 1d, the longest length r2 of the second filler P2 contained in the second photosensitive glass paste 13 is greater than 0 and less than or equal to the wavelength λ of ultraviolet UV. Therefore, the manufacturing method of the photocoupler 1d can improve the processing accuracy of the photocoupler 1d.

[0088] [Fifth variation] [Structure of the photoelectric conversion circuit module 50] The photoelectric conversion circuit module 50 according to the fifth modified example will be described below with reference to the drawings. Figure 18 is a perspective view of the photoelectric conversion circuit module 50 and the optical fiber 5. In Figure 18, only representative optical couplers 1, optical fibers 5, and optical waveguides OW from among the multiple optical couplers 1, multiple optical fibers 5, and multiple optical waveguides OW are given reference numerals. Figure 19 is a cross-sectional view AA of the photoelectric conversion circuit module 50 and the optical fiber 5.

[0089] As shown in Figure 18, the photoelectric conversion circuit module 50 comprises a plurality of optical couplers 1, a substrate 51, and a photoelectric conversion circuit 52. The plurality of optical couplers 1 and the photoelectric conversion circuit 52 are mounted on the substrate 51. The photoelectric conversion circuit 52 is located in the center of the substrate 51 when viewed in the first direction DIR1. The plurality of optical couplers 1 are located around the photoelectric conversion circuit 52 when viewed in the first direction DIR1. Each of the plurality of optical fibers 5 is fixed to the respective optical fiber fixing part 4 of the plurality of optical couplers 1. Note that the number of optical couplers 1 is not limited to a plurality, and may be one. Also, the photoelectric conversion circuit 52 does not have to be located in the center of the substrate 51 when viewed in the first direction DIR1. Also, the plurality of optical couplers 1 do not have to be located around the photoelectric conversion circuit 52 when viewed in the first direction DIR1. Furthermore, the photoelectric conversion circuit module 50 may include optical couplers 1a, 1b, 1c, or 1d instead of optical coupler 1.

[0090] The substrate 51 has a plate shape with two main surfaces aligned in the first direction DIR1. However, as shown in Figure 19, an optical waveguide OW and a mirror M are provided inside the substrate 51. The optical waveguide OW is provided between the photoelectric conversion circuit 52 and each of the multiple optical couplers 1. The mirror M is provided in the opposite direction to the first direction DIR1 from the reflecting section 3. The light L emitted from the photoelectric conversion circuit 52 passes through the optical waveguide OW.

[0091] Multiple optical couplers 1 are mounted on the main surface of the substrate 51 located in the first direction DIR1 of the two main surfaces. More specifically, the mounting surface S21 is mounted on the main surface of the substrate 51 located in the first direction DIR1 of the two main surfaces.

[0092] The photoelectric conversion circuit 52 is mounted on the main surface of the substrate 51 located in the first direction DIR1 of the two main surfaces. The photoelectric conversion circuit 52 converts an electrical signal into light incident on the optical coupler 1, or converts light emitted from the optical coupler 1 into an electrical signal. The case in which the photoelectric conversion circuit 52 converts an electrical signal into light incident on the optical coupler 1 will be explained below.

[0093] The photoelectric conversion circuit 52 converts an electrical signal into light L that is incident on each of the multiple optical couplers 1. The light L emitted from the photoelectric conversion circuit 52 travels through the optical waveguide OW in the second direction DIR2. The light L traveling through the optical waveguide OW in the second direction DIR2 is reflected by the mirror M. As a result, the direction of travel of the light L is changed from the second direction DIR2 to the first direction DIR1. Subsequently, the light L is incident on the incident surface S11 of the optical coupler 1, and the optical coupler 1 changes the direction of travel from the first direction DIR1 to the second direction DIR2, and it is emitted from the exit surface S12 of the optical coupler 1. As a result, the light L is incident on each of the five optical fibers 5.

[0094] The photoelectric conversion circuit module 50 described above also produces the same effect as the optical coupler 1.

[0095] [Sixth variation] [Structure of photoelectric conversion circuit module 50a] The photoelectric conversion circuit module 50a according to the sixth modification will be described below with reference to the drawings. Figure 20 is a perspective view of the photoelectric conversion circuit module 50a and the optical fiber 5. In Figure 20, only representative optical couplers 1 and optical fibers 5 among the multiple optical couplers 1 and multiple optical fibers 5 are given reference numerals. In addition, only the parts of the photoelectric conversion circuit module 50a according to the sixth modification that differ from the photoelectric conversion circuit module 50 according to the fifth modification will be described, and the rest will be omitted.

[0096] The photoelectric conversion circuit module 50a differs from the photoelectric conversion circuit module 50 in that the substrate 51 is a semiconductor substrate and the substrate 51 includes multiple light-emitting sections 53. The number of light-emitting sections 53 is not limited to multiple; it may be just one.

[0097] Each of the multiple light-emitting units 53 is, for example, a surface light-emitting element formed on the main surface of the substrate 51 located in the first direction DIR1 of the two main surfaces. Each of the multiple light-emitting units 53 is, for example, a VCSEL (Vertical Cavity Surface Emitting Laser). Each of the multiple light-emitting units 53 emits light L based on an electrical signal generated by the photoelectric conversion circuit 52. The light L emitted from each of the multiple light-emitting units 53 is incident on each of the multiple optical fibers 5 via each of the multiple optical couplers 1.

[0098] The photoelectric conversion circuit module 50a described above also produces the same effect as the photoelectric conversion circuit module 50.

[0099] [Seventh variation] [Structure of Optical Transceiver 100] The optical transceiver 100 will be described below with reference to the drawings. Figure 21 is a perspective view of the optical transceiver 100 and the optical fiber 5. In Figure 21, only a representative optical fiber 5 out of the five optical fibers 5 is given a reference numeral. Regarding the optical transceiver 100 according to the seventh modification, only the parts that differ from the photoelectric conversion circuit module 50a according to the sixth modification will be described, and the rest will be omitted.

[0100] The optical transceiver 100 differs from the photoelectric conversion circuit module 50a in that it has one optical coupler 1 and one optical emission unit 53.

[0101] The light L emitted from the light emission unit 53 enters each of the five optical fibers 5 via the optical coupler 1, or the light L emitted from each of the five optical fibers 5 enters the photoelectric conversion circuit 52 via the optical coupler 1.

[0102] The optical transceiver 100 described above also produces the same effect as the photoelectric conversion circuit module 50a.

[0103] [Other embodiments] The optical couplers according to the present invention are not limited to optical couplers 1, 1a, 1b, 1c, and 1d, but can be modified within the scope of the gist thereof. Furthermore, the structures of optical couplers 1, 1a, 1b, 1c, and 1d may be arbitrarily combined.

[0104] The photoelectric conversion circuit module according to the present invention is not limited to the photoelectric conversion circuit module 50 and the photoelectric conversion circuit module 50a, but can be modified within the scope of its gist. Furthermore, the structures of the photoelectric conversion circuit module 50 and the photoelectric conversion circuit module 50a may be arbitrarily combined.

[0105] The optical transceiver according to the present invention is not limited to optical transceiver 100, but can be modified within the scope of its gist.

[0106] The present invention has the following configuration.

[0107] (1) A preparation step of preparing a translucent substrate having a first main surface and a second main surface aligned in a first direction, A first coating step of applying a first photosensitive glass paste containing a first filler to the first main surface, A masking step involves placing a grayscale mask formed by a binary pattern onto the second main surface, An exposure step of irradiating the second main surface with ultraviolet light to expose the first photosensitive glass paste, A developing step in which the grayscale mask is removed from the second main surface and the first photosensitive glass paste is developed, A curing step is performed to remove the light-transmitting substrate from the developed first photosensitive glass paste and to cure the first photosensitive glass paste, It is equipped with, The longest length of the first filler is longer than the wavelength of ultraviolet light. A method for manufacturing an optical coupler.

[0108] (2) Between the first coating step and the exposure step, there is a second coating step of applying a second photosensitive glass paste to the first photosensitive glass paste. In the exposure step, the first photosensitive glass paste and the second photosensitive glass paste are exposed to light. In the development step described above, the first photosensitive glass paste and the second photosensitive glass paste are developed. In the curing step, the first photosensitive glass paste and the second photosensitive glass paste are cured. The second photosensitive glass paste contains a second filler, and the content of the second filler in the second photosensitive glass paste is lower than the content of the first filler in the first photosensitive glass paste. Alternatively, the second photosensitive glass paste may not contain the second filler. (1) A method for manufacturing the optical coupler described above.

[0109] (3) Between the first coating step and the exposure step, there is a second coating step of applying a second photosensitive glass paste containing a second filler to the first photosensitive glass paste. In the exposure step, the first photosensitive glass paste and the second photosensitive glass paste are exposed to light. In the development step described above, the first photosensitive glass paste and the second photosensitive glass paste are developed. In the curing step, the first photosensitive glass paste and the second photosensitive glass paste are cured. The longest length of the second filler is greater than 0 and less than or equal to the wavelength of ultraviolet light. (1) A method for manufacturing the optical coupler described above.

[0110] (4) The first filler includes a filler having a non-spherical shape. A method for manufacturing an optical coupler as described in any of (1) to (3).

[0111] (5) A translucent substrate having a first main surface and a second main surface aligned in a first direction, comprising a preparation step for preparing a translucent substrate containing a third filler, A first coating step of applying a first photosensitive glass paste to the first main surface, A masking step involves placing a grayscale mask formed by a binary pattern onto the second main surface, An exposure step of irradiating the second main surface with ultraviolet light to expose the first photosensitive glass paste, A developing step in which the grayscale mask is removed from the second main surface and the first photosensitive glass paste is developed, A curing step is performed to remove the light-transmitting substrate from the developed first photosensitive glass paste and to cure the first photosensitive glass paste, It is equipped with, The longest length of the third filler is longer than the wavelength of ultraviolet light. A method for manufacturing an optical coupler.

[0112] (6) The third filler includes a filler having a non-spherical shape. (5) A method for manufacturing the optical coupler described above.

[0113] (7) A photocoupler comprising a first photosensitive glass paste containing a first filler, The longest length of the first filler is longer than the wavelength of ultraviolet light irradiated onto the grayscale mask formed by the binary pattern. Optical coupler.

[0114] (8) A first glass portion comprising a first glass and a first filler mixed within the first glass, A second glass portion that includes at least a second glass and is connected to the first glass portion, It is equipped with, The second glass portion contains a second filler mixed within the second glass, and the content of the second filler in the second glass portion is lower than the content of the first filler in the first glass portion. Alternatively, the second glass portion does not include the second filler. Optical coupler.

[0115] (9) The first glass section and The transparent portion connected to the first glass portion, It is equipped with, The first glass portion comprises glass and a first filler mixed within the glass. The permeable portion comprises a medium and a second filler mixed within the medium. The longest length of the second filler is different from the longest length of the first filler. Optical coupler.

[0116] (10) The medium is glass. (9) The optical coupler described above.

[0117] (11) The first filler includes a filler having a non-spherical shape. (7) The optical coupler described in any of (10).

[0118] (12) The aforementioned transparent portion is a light-transmitting substrate. The optical coupler described in (9) or (10).

[0119] (13) The second filler includes a filler having a non-spherical shape. The optical coupler described in (12).

[0120] (14) (7) to (13) an optical coupler, circuit board and The substrate is equipped with a photoelectric conversion circuit, The photoelectric conversion circuit converts an electrical signal into light incident on the optical coupler, or converts light emitted from the optical coupler into an electrical signal. Photoelectric conversion circuit module.

[0121] (15) The substrate is a semiconductor substrate and includes a light-emitting portion that emits light, The optical coupler is mounted on the substrate, (14) The photoelectric conversion circuit module described above.

[0122] (16) (7) to (13) comprising an optical coupler, Optical transceiver. [Explanation of symbols]

[0123] 1,1a,1b,1c,1d: Optical coupler 2: Holding part 3:Reflector 4: Optical fiber fixing section 5: Fiber optic 10: Grayscale Mask 11: Transparent substrate 12: First photosensitive glass paste 13: Second photosensitive glass paste 15: pixels 16: Unit Domain 17: Runners Club 21: First side wall section 22: Second side wall section 23: Third side wall section 24: Bottom 31: Prism section 32: Focusing lens section 50,50a: Photoelectric conversion circuit module 51: Circuit board 52: Photoelectric conversion circuit 53: Light Emitting Section 100: Optical transceiver A1,A2:Area A11,A12,A21,A22: Square part DIR1: 1st direction DIR2:Second direction DIR3: Third direction G:Groove I: Light intensity L:Light M: Mirror M1: Glass M2: Medium OW: Optical waveguide P1: First filler P2: Second filler P3: Third filler S1: End face S11:Incidence surface S12: Output surface S2: Incident surface of the prism section S21: Implementation side S3: Reflecting surface of the prism section S4: Prism section emission surface SU11: 1st main surface SU12: Second main surface UV: Ultraviolet light a: Light transmission area b: Light shielding area

Claims

1. A preparation step of preparing a translucent substrate having a first main surface and a second main surface aligned in a first direction, A first coating step involves applying a first photosensitive glass paste containing a first filler to the first main surface, A masking step involves placing a grayscale mask, which is formed of a binary pattern having a periodic structure of light-transmitting regions and light-shielding regions, on the second main surface. An exposure step in which ultraviolet light is irradiated onto the second main surface to expose the first photosensitive glass paste, A developing step in which the grayscale mask is removed from the second main surface and the first photosensitive glass paste is developed, A curing step is performed to remove the light-transmitting substrate from the developed first photosensitive glass paste and to cure the first photosensitive glass paste, It is equipped with, The longest length of the first filler is longer than the wavelength of ultraviolet light, and is 380 nm or longer. A method for manufacturing an optical coupler.

2. Between the first coating step and the exposure step, there is a second coating step in which a second photosensitive glass paste is applied to the first photosensitive glass paste. In the exposure step, the first photosensitive glass paste and the second photosensitive glass paste are exposed to light. In the development step, the first photosensitive glass paste and the second photosensitive glass paste are developed. In the curing step, the first photosensitive glass paste and the second photosensitive glass paste are cured. The second photosensitive glass paste contains a second filler, and the content of the second filler in the second photosensitive glass paste is lower than the content of the first filler in the first photosensitive glass paste. Alternatively, the second photosensitive glass paste may not contain the second filler. A method for manufacturing an optical coupler according to claim 1.

3. Between the first coating step and the exposure step, there is a second coating step in which a second photosensitive glass paste containing a second filler is applied to the first photosensitive glass paste. In the exposure step, the first photosensitive glass paste and the second photosensitive glass paste are exposed to light. In the development step, the first photosensitive glass paste and the second photosensitive glass paste are developed. In the curing step, the first photosensitive glass paste and the second photosensitive glass paste are cured. The longest length of the second filler is greater than 0 and less than or equal to the wavelength of ultraviolet light. A method for manufacturing an optical coupler according to claim 1.

4. The first filler includes a filler having a non-spherical shape. A method for manufacturing an optical coupler according to any one of claims 1 to 3.

5. A light-transmitting substrate having a first main surface and a second main surface aligned in a first direction, comprising a preparation step for preparing a light-transmitting substrate containing a third filler, A first coating step involves applying a first photosensitive glass paste to the first main surface, A masking step involves placing a grayscale mask formed by a binary pattern onto the second main surface, An exposure step in which ultraviolet light is irradiated onto the second main surface to expose the first photosensitive glass paste, A developing step in which the grayscale mask is removed from the second main surface and the first photosensitive glass paste is developed, A curing step is performed to remove the light-transmitting substrate from the developed first photosensitive glass paste and to cure the first photosensitive glass paste, It is equipped with, The longest length of the third filler is longer than the wavelength of ultraviolet light. A method for manufacturing an optical coupler.

6. The third filler includes a filler having a non-spherical shape. A method for manufacturing an optical coupler according to claim 5.

7. A photocoupler comprising a first photosensitive glass paste containing a first filler, The longest length of the first filler is longer than the wavelength of ultraviolet light irradiated onto the grayscale mask formed by the binary pattern, and is 380 nm or longer. Optical coupler.

8. A plate-shaped bottom portion comprising a first glass and a first filler mixed within the first glass, A reflective portion including at least a second glass and connected to the bottom, An optical fiber fixing portion, which includes at least the second glass and is connected to the bottom, It is equipped with, The longest length of the first filler is 380 nm or more. The reflective portion and the optical fiber fixing portion each contain a second filler mixed in the second glass, and the content of the second filler contained in the second glass is lower than the content of the first filler contained in the bottom portion. Alternatively, the reflective portion and the optical fiber fixing portion each do not include the second filler. Optical coupler.

9. The reflective portion includes a reflective surface that reflects light that has passed through the bottom portion toward the optical fiber fixing portion, The optical coupler according to claim 8.

10. The first glass section and The transparent portion connected to the first glass portion, It is equipped with, The first glass portion comprises glass and a first filler mixed within the glass. The permeable portion comprises a medium and a third filler mixed within the medium. The longest length of the first filler is 380 nm or more. The longest length of the third filler is different from the longest length of the first filler. Optical coupler.

11. The medium is glass. The optical coupler according to claim 10.

12. The first filler includes a filler having a non-spherical shape. The optical coupler according to any one of claims 7 to 11.

13. The aforementioned transparent portion is a light-transmitting substrate. The optical coupler according to claim 10 or claim 11.

14. The third filler includes a filler having a non-spherical shape. The optical coupler according to claim 13.

15. An optical coupler according to any one of claims 7 to 11, circuit board and The substrate is equipped with a photoelectric conversion circuit, The photoelectric conversion circuit converts an electrical signal into light incident on the optical coupler, or converts light emitted from the optical coupler into an electrical signal. Photoelectric conversion circuit module.

16. The substrate is a semiconductor substrate and includes a light-emitting portion that emits light, The optical coupler is mounted on the substrate, The photoelectric conversion circuit module according to claim 15.

17. The optical coupler comprises the optical coupler according to any one of claims 7 to 11. Optical transceiver.

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