Optical device and method for mounting electronic component

Abstract

To provide an optical device capable of surely connecting wiring arranged along one surface of a substrate and a connection terminal of an electronic component spreading vertically to the one surface of the substrate without connection failure, and to provide a method of mounting the electronic component.SOLUTION: An optical device includes a laminated substrate in which a plurality of functional layers are laminated, and an optical component and an electronic component disposed on the laminated substrate, wherein the functional layers include at least a first functional layer on which the optical component is placed and a second functional layer which is disposed below the first functional layer and on which the electronic component is placed, a first wiring is provided on one surface of the first functional layer, and a second wiring is provided on one surface of the second functional layer. The connection terminal of the electronic component is electrically connected to both the first wiring and the second wiring via a conductive material.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an optical device and a method for mounting electronic components. [Background technology]

[0002] In recent years, augmented reality (AR) glasses and small projectors have been attracting attention, and small planar lightwave circuits (PLCs) using laser diodes are also attracting attention. These laser diodes are capable of displaying images with high energy efficiency.

[0003] For example, Patent Document 1 describes a light source with a monitoring function that can be used in a small projector. The light source with a monitoring function described in Patent Document 1 has a detection element using a semiconductor photodiode (PD). The semiconductor photodiode monitors the light output. The light source with a monitoring function described in Patent Document 1 adjusts the white balance based on the monitoring result of the light output.

[0004] Semiconductor photodiodes come in various types, including the axial lead type known as the CAN type, and the SMD (Surface Mount Device) type, which is mounted on a circuit board. When a semiconductor photodiode is to be housed in a small package for an optical device (light source module) such as a light source with monitoring functions, the CAN type is physically large and not suitable for miniaturization, so the SMD type is used.

[0005] SMD-type semiconductor photodiodes typically have a rectangular parallelepiped outer shape with a light-receiving surface on one side and connection terminals (electrode terminals) on the other opposite side. When the optical axis of the incident light is aligned with one surface of the mounting board, such SMD-type semiconductor photodiodes are mounted so that the light-receiving surface and connection terminals are perpendicular to the surface of the mounting board.

[0006] When mounting a semiconductor photodiode such as that described above on one surface of a mounting substrate, in order to electrically connect the wiring pattern extending along one surface of the mounting substrate and the connection terminals extending perpendicular to one surface of the mounting substrate, a conductive material is formed to fill the gaps between them using a conductive resin such as silver paste. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Publication No. 2018-180513 Summary of the Invention [Problem to be solved by the invention]

[0008] However, the conductive material that electrically connects the wiring pattern and the connection terminal of the semiconductor photodiode as described above has fluidity when formed, and therefore the cross section becomes smaller as the formed shape goes upward, such as a cone shape, and the contact area with the connection terminal of the semiconductor photodiode becomes smaller. This poses a problem in that poor electrical connection is likely to occur between the wiring pattern of the mounting board and the connection terminal of the semiconductor photodiode.

[0009] The present invention has been made in consideration of the above circumstances, and aims to provide an optical device and a method for mounting electronic components that can reliably connect wiring arranged along one surface of a substrate to connection terminals of electronic components that extend perpendicular to one surface of the substrate without causing connection failures. [Means for solving the problem]

[0010] An optical device according to one embodiment of the present invention is an optical device having a laminated substrate on which multiple functional layers are stacked, and optical and electronic components arranged on the laminated substrate, wherein the functional layer has at least a first functional layer on which the optical components are placed, and a second functional layer arranged below the first functional layer on which the electronic components are placed, a first wiring is provided on one surface of the first functional layer, a second wiring is provided on one surface of the second functional layer, and the connection terminals of the electronic components are electrically connected to both the first wiring and the second wiring via a conductive material.

[0011] According to the present invention, even if the connection terminals of the electronic component are mounted so as to extend perpendicularly to the extension direction of the second wiring that extends along one surface of the second functional layer, which is the mounting surface, poor connection of the connection terminals of the electronic component can be prevented. That is, by connecting the connection terminals to both the first wiring and the second wiring, which are wirings with the same function, via a conductive material, the continuity of the connection terminals can be ensured.

[0012] In one embodiment of the present invention, it is preferable that the first wiring and the second wiring are electrically connected by an interlayer connection wiring provided on the laminated substrate.

[0013] In one embodiment of the present invention, the first functional layer may have a component mounting hole formed therein that penetrates the first functional layer, and the electronic component may be mounted in the component mounting hole.

[0014] In one embodiment of the present invention, the conductive material may be interposed between an inner peripheral surface of the component mounting hole and the connection terminal.

[0015] In one embodiment of the present invention, the end of the first wiring may be located at a position set back from an inner circumferential surface of the component mounting hole.

[0016] In one embodiment of the present invention, an electrode recess may be formed in a position adjacent to an end of the wiring of the first functional layer, the electrode recess being cut out in a direction that widens the component mounting hole.

[0017] In addition, in one embodiment of the present invention, a component mounting recess that is recessed in the thickness direction may be formed in the area of ​​the second functional layer that is exposed from the component mounting hole, and a component fixing resin layer may be formed that fills the inside of the component mounting recess and contacts at least the bottom of the electronic component.

[0018] In addition, in one embodiment of the present invention, the conductive material may be a conductive resin.

[0019] In one embodiment of the present invention, the electronic component may be a light receiving element, the optical component may include an optical waveguide, and the light receiving element may receive at least a portion of the light propagating through the optical waveguide.

[0020] One embodiment of the present invention provides a method for mounting an electronic component on a laminated substrate having at least a first functional layer having a first wiring provided on one surface thereof, a second functional layer arranged below the first functional layer and having a second wiring provided on one surface thereof, and a component mounting hole that penetrates the first functional layer to expose one surface of the second functional layer. The method includes at least a mounting step of inserting the electronic component into the component mounting hole and positioning and mounting the electronic component on one surface of the second functional layer, and a connection step of providing a conductive material between one connection terminal of the electronic component and the first wiring and the second wiring to electrically connect them.

[0021] In addition, in one embodiment of the present invention, the connection process may be a process in which a conductive resin is used as the conductive material, and the conductive resin is filled between the connection terminal and the inner surface of the component mounting hole, thereby electrically connecting one connection terminal of the electronic component to the first wiring and the second wiring. [Effects of the Invention]

[0022] According to the present invention, it is possible to provide an optical device and a method for mounting electronic components that can reliably connect wiring arranged along one surface of a substrate to connection terminals of electronic components that extend perpendicular to one surface of the substrate without causing connection failures. [Brief explanation of the drawings]

[0023] [Figure 1] FIG. 1 is a perspective view showing the appearance of the inside of an optical device according to a first embodiment of the present invention as viewed from above. [Figure 2] FIG. 2 is a plan view showing the interior of the optical device of FIG. 1 as viewed from above. [Figure 3] FIG. 3 is a cross-sectional view of the laminated substrate constituting the optical device taken along the line AA' in FIG. [Figure 4] FIG. 4 is an enlarged perspective view of a main part showing a portion where an electronic component is mounted. [Figure 5] FIG. 5 is an enlarged cross-sectional view of a main part showing a portion where an electronic component is mounted. [Figure 6] FIG. 6 is a cross-sectional view showing the light source unit (optical device) of the second embodiment, taken along the line AA' in FIG. [Figure 7] FIG. 7 is an enlarged perspective view of a main part showing a portion where an electronic component is mounted. [Figure 8] FIG. 8 is an enlarged perspective view of a main part showing a mounting portion of electronic components in a light source unit (optical device) according to the third embodiment. [Figure 9] FIG. 9 is an enlarged perspective view of a main part showing a mounting portion of electronic components in a light source unit (optical device) according to the fourth embodiment. [Figure 10] FIG. 10 is a plan view showing the state in which electronic components are mounted on the circuit board shown in FIG. 9 and viewed from above. [Figure 11] FIG. 11 is an enlarged perspective view of a main part showing a mounting portion of electronic components in a light source unit (optical device) according to the fifth embodiment. [Figure 12] FIG. 12 is an enlarged perspective view of a main part of the state in which electronic components are mounted on the board shown in FIG. [Figure 13] FIG. 13 is an enlarged cross-sectional view of a main part of the light source unit of the fifth embodiment taken along the stacking direction. DETAILED DESCRIPTION OF THE INVENTION

[0024] An optical device and a method for mounting electronic components, which are embodiments of the present invention, will be described below with reference to the drawings. Note that the embodiments shown below are specifically described to provide a better understanding of the gist of the invention, and do not limit the present invention unless otherwise specified. Furthermore, the drawings used in the following description may show essential parts enlarged for convenience in order to make the features of the present invention easier to understand, and the dimensional proportions of each component may not necessarily be the same as those in reality.

[0025] (Optical device: first embodiment) In the following embodiments, a light source unit with a monitoring function (hereinafter sometimes referred to as a light source unit) that can be suitably used in AR glasses or a small projector will be described as an example of an optical device. Fig. 1 is an external perspective view showing the interior of an optical device according to a first embodiment of the present invention as viewed from above. Fig. 2 is a plan view showing the interior of the optical device as viewed from above. Fig. 3 is a cross-sectional view of a laminated substrate constituting the optical device, taken along line A-A' in Fig. 2.

[0026] The light source unit (optical device) 10 of this embodiment is a multiplexer that combines light of each of the three primary colors of light: red (R), green (G), and blue (B). Such an optical device 10 is used, for example, as a multiplexer mounted on a head-mounted display. The light source unit 10 has a laminated substrate 40, an LD (optical semiconductor element) 30 provided on the laminated substrate 40, a PLC (optical component) 50 which is an optical waveguide, and a light receiving element (electronic component) 60.

[0027] The laminated substrate 40 is formed by laminating multiple functional layers, seven functional layers 41 to 47 in this embodiment from bottom to top. Of these, functional layers 45 to 47 have a cavity portion 48 formed therein, with the interior being hollow and the periphery remaining wall-like. With this configuration, the laminated substrate 40 has a cavity structure in which the LD 30, the PLC 50, and the light-receiving element 60 are housed in the cavity portion 48. The upper open surface of the cavity portion 48 is closed by a lid (not shown) made of, for example, a metal plate. This lid may be fixed by resistance welding to a metal frame formed on the functional layer 47 by nickel-gold plating.

[0028] An opening 81, the surface of which is covered with a cover glass 82, is formed in one of the side walls that define the cavity 48. This opening 81 is a window that allows the three-color light (projection light) emitted from the main core of the PLC 50 to exit the cavity 48. The inside of the cavity 48 is kept airtight and is replaced with, for example, an inert gas. A collimating lens or the like may also be arranged inside the opening 81.

[0029] The LD (optical semiconductor element) 30 is composed of an LD 30-1 that emits red light, an LD 30-2 that emits green light, and an LD 30-3 that emits blue light. The LDs 30-1, 30-2, and 30-3 are arranged at predetermined intervals in a direction substantially perpendicular to the emission direction of the light emitted from each LD 30, and may be provided, for example, on the upper surface of a subcarrier.

[0030] Needless to say, LD30 can use light other than red (R), green (G), and blue (B) shown in this embodiment, and the order in which red (R), green (G), and blue (B) are mounted does not necessarily have to be this order and can be changed as appropriate. For example, red light having a peak wavelength of 605 nm or more and 750 nm or less can be used, green light having a peak wavelength of 495 nm or more and 570 nm or less can be used, and blue light having a peak wavelength of 405 nm or more and 494 nm or less can be used.

[0031] The multiple functional layers 41 to 47 that make up the laminated substrate 40 may be made of, for example, ceramic thin plates, which are dielectric materials. This allows the light source unit 10 to be formed as a ceramic package. Semi-cylindrical notches 11, known as casters, may be formed on the outer circumferential surface of the light source unit 10. When the light source unit 10 is fixed to a mounting board or the like by solder, for example, these notches allow the creeping of solder into the notches 11 to be visually confirmed, thereby improving the reliability of the mounting of the light source unit 10.

[0032] In this embodiment, of the multiple functional layers 41 to 47, the third functional layer from the bottom forms the second functional layer 43 that supports the light receiving element (electronic component) 60, and the fourth functional layer from the bottom forms the first functional layer 44 that supports the PLC (optical component) 50.

[0033] The PLC (optical component) 50 is formed using a quartz plate using a semiconductor process including well-known photolithography and dry etching used for forming fine structures such as integrated circuits. The PLC 50 includes main cores (optical waveguides) 51-1, 51-2, and 51-3 corresponding to the LDs 30-1, 30-2, and 30-3, respectively, sub-cores (optical waveguides) 52-1, 52-2, and 52-3 branching off midway through the main cores 51-1, 51-2, and 51-3, respectively, and a cladding 53 surrounding the main cores 51 and the sub-cores 52.

[0034] Then, the main cores 51-1, 51-2, and 51-3 branch into sub-cores 52-1, 52-2, and 52-3 along the light propagation direction, and then merge into one to form the multiplexed main core 51-4, which reaches the main output end 55 of the PLC 50. The main output end 55 of the multiplexed main core 51-4 faces the opening 81, and the main output light obtained by multiplexing the three color lights is output to the outside of the cavity 48 through, for example, a cover glass 82 of the opening 81.

[0035] Meanwhile, the sub-cores 52-1, 52-2, and 52-3 merge into one along the light propagation direction and reach a sub-output end 56 of the PLC 50 as a multiplexing sub-core 52-4. The sub-output end 56 of the multiplexing sub-core 52-4 is disposed opposite a light-receiving surface 61 of a light-receiving element (electronic component) 60 (described later), and light emitted from the sub-output end 56 enters the light-receiving element (electronic component) 60. In other words, the light-receiving element (electronic component) 60 is disposed so as to receive the light propagating through the multiplexing sub-core 52-4. The sub-output end 56 and the light-receiving surface 61 may be optically connected.

[0036] There are no particular limitations on the thickness of the clad 53 and the widthwise dimensions of the main core 51 and the sub-core 52. For example, the main core 51 and the sub-core 52 each having a widthwise dimension of about several microns are disposed in the clad 53 having a thickness of about 50 μm.

[0037] The main core 51, the sub-core 52, and the cladding 53 are made of, for example, quartz, and the refractive indexes of the main core 51 and the sub-core 52 are higher by a predetermined value than the refractive index of the cladding 53. As a result, light incident on each of the main core 51 and the sub-core 52 propagates through each core while being totally reflected at the interface between each core and the cladding 53. The main core 51 and the sub-core 52 may each be doped with an impurity such as germanium (Ge) in an amount corresponding to the aforementioned predetermined value.

[0038] In the PLC 50 configured as described above, the light beams output from the LDs 30-1, 30-2, and 30-3 enter the main cores (optical waveguides) 51-1, 51-2, and 51-3, respectively, and propagate toward the main output end 55. During this propagation, at least a portion of the propagating light beams is branched into the sub-cores 52-1, 52-2, and 52-3. The light beams propagating through the main cores 51-1, 51-2, and 51-3 are then combined and emitted as main output light from the main output end 55 of the combined main core 51-4.

[0039] On the other hand, the light beams demultiplexed from the main core 51 and propagating through the sub-cores 52-1, 52-2, and 52-3 are also multiplexed and emitted from the sub-emitting end 56 of the multiplexing sub-core 52-4. The sub-output light emitted from the sub-output end 56 is used as monitoring light for checking the light intensity and color tone of the main output light, for example, and is incident on a light receiving element (electronic component) 60 and photoelectrically converted.

[0040] The light receiving element (electronic component) 60 has, for example, a rectangular parallelepiped outer shape and is placed (mounted) on one surface 43a of the second functional layer 43 of the laminated substrate 40. In the mounted state, the light receiving element (electronic component) 60 has a light receiving surface 61 formed on one vertical surface 60a perpendicular to the one surface 43a of the second functional layer 43. Furthermore, a pair of connection terminals 62a, 62b is formed on the other vertical surface 60b opposite to the one vertical surface 60a. These connection terminals 62a, 62b may be flat metal plates that extend perpendicular to the one surface 43a of the second functional layer 43.

[0041] A component mounting hole 71 is formed in the first functional layer 44 of the laminated substrate 40, exposing one surface 43a of the second functional layer 43. The component mounting hole 71 is formed at a position overlapping the mounting position of the light receiving element 60, and the light receiving element 60 is mounted so as to pass through the component mounting hole 71. As a result, the connection terminals 62a, 62b are formed so as to extend parallel to the inner peripheral surface 71a of the component mounting hole 71 when the light receiving element 60 is mounted.

[0042] Furthermore, when the first functional layer 44 and the second functional layer 43 are located apart, for example, when one or more other functional layers are further stacked between the first functional layer 44 and the second functional layer 43, such component mounting holes 71 can also be formed to penetrate the first functional layer 44 and the other functional layers.

[0043] The second functional layer 43 is formed with a second wiring 74a electrically connected to one connection terminal 62a of the light receiving element 60, and a second wiring 74b electrically connected to the other connection terminal 62b of the light receiving element 60. The second wirings 74a and 74b are partially exposed from the first functional layer 44 in the opening region of the component mounting hole 71.

[0044] Meanwhile, the first functional layer 44 also has a first wiring 73a electrically connected to one connection terminal 62a of the light receiving element 60, and a first wiring 73b electrically connected to the other connection terminal 62b of the light receiving element 60 formed thereon.

[0045] The first wirings 73a, 73b and second wirings 74a, 74b may be, for example, tungsten wiring or molybdenum wiring, and may be formed to a thickness of about 5 μm to 30 μm. Alternatively, electroless nickel plating may be formed on the tungsten wiring or molybdenum wiring to a thickness of about 1 μm to 10 μm, and electroless gold plating may be further formed to a thickness of about 1 μm to 4 μm.

[0046] An interlayer connection wiring (via wiring) 75a that electrically connects the first wiring 73a and the second wiring 74a, and an interlayer connection wiring (via wiring) 75b that electrically connects the first wiring 73b and the second wiring 74b are formed in the first functional layer 44. These interlayer connection wirings (via wiring) 75a and 75b can be formed, for example, by forming through holes (via holes) in the first functional layer 44 and filling the insides of these through holes with a conductor.

[0047] As a result, the first wiring 73a and the second wiring 74a are wirings with the same function that branch into two. Similarly, the first wiring 73b and the second wiring 74b are wirings with the same function that branch into two.

[0048] As shown in the enlarged view of the main part in Figure 4, the first wirings 73a, 73b formed on one surface 44a of the first functional layer 44 are formed so that the wiring ends 73a1, 73b1 that are connected to the connection terminals 62a, 62b of the light receiving element 60, respectively, by the conductive material 77 described later are positioned facing the inner surface 71a of the component mounting hole 71.

[0049] As shown in the enlarged view of the main part in Figure 5, the connection terminal 62a of the light receiving element (electronic component) 60 is electrically connected to both the first wiring 73a formed in the first functional layer 44 and the second wiring 74a formed in the second functional layer 43 via a conductive material 77.

[0050] Similarly, the connection terminal 62b of the light receiving element (electronic component) 60 is electrically connected to both the first wiring 73b formed in the first functional layer 44 and the second wiring 74b formed in the second functional layer 43 via the conductive material 77.

[0051] The conductive material 77 is formed to fill the gap between the connection terminals 62a, 62b of the light-receiving element (electronic component) 60 extending in the stacking direction and the inner surface 71a of the component mounting hole 71, and at the bottom it contacts the second wirings 74a, 74b extending along one surface 43a of the second functional layer 43, and at the top it contacts and covers the wiring ends 73a1, 73b1 of the first wirings 73a, 73b extending along one surface 44a of the first functional layer 44, respectively.

[0052] Such conductive material 77 may be, for example, a conductive resin such as a silver paste made by mixing silver particles and a hardening resin, or a copper paste made by mixing copper particles and a hardening resin.

[0053] According to the light source unit (optical device) 10 of this embodiment having the above-described configuration, even if the connection terminals 62a, 62b of the light receiving element (electronic component) 60 are mounted so as to extend perpendicular to the extension direction of the second wiring 74a, 74b extending along one surface 43a of the second functional layer 43, which is the mounting surface, poor connection of the connection terminals 62a, 62b of the light receiving element (electronic component) 60 can be prevented.

[0054] That is, the continuity of the connection terminal 62a can be ensured by connecting one connection terminal 62a to both the first wiring 73a and the second wiring 74a, which are wirings having the same function, via the conductive material 77. Similarly, the continuity of the connection terminal 62b can be ensured by connecting one connection terminal 62b to both the first wiring 73b and the second wiring 74b, which are wirings having the same function, via the conductive material 77.

[0055] Furthermore, the conductive material 77 spreads into the narrow gap between the connection terminals 62a, 62b and the inner surface 71a of the component mounting hole 71, and the width of the conductive material 77 changes little in the vertical direction. Furthermore, the conductive material 77 is formed on the upper side so as to cover the wiring ends 73a1, 73b1 of the first wirings 73a, 73b, respectively, thereby ensuring a wide contact area with the first wirings 73a, 73b and the second wirings 74a, 74b, respectively, and ensuring reliable conductivity.

[0056] In this embodiment, the first functional layer 44 and the second functional layer 43 are formed as adjacent layers, but the first functional layer 44 and the second functional layer 43 may be located at a distance from each other, for example, one or more additional functional layers may be further stacked between the first functional layer 44 and the second functional layer 43.

[0057] In addition, in this embodiment, the second functional layer 43 constitutes the third layer from the bottom of the laminated substrate 40, and the first functional layer 44 constitutes the fourth layer, but the positions of the first functional layer and the second functional layer within the laminated substrate are not limited, as long as at least the second functional layer is arranged lower than the first functional layer.

[0058] (Optical device: second embodiment) A light source unit (optical device) according to a second embodiment of the present invention will be described below. Note that the same components as those in the first embodiment are given the same reference numerals, and redundant description will be omitted. Fig. 6 is a cross-sectional view showing a light source unit (optical device) of a second embodiment, taken along line AA' in Fig. 2. Fig. 7 is an enlarged perspective view of a main part showing a portion where electronic components are mounted.

[0059] In the light source unit (optical device) 110 of this embodiment, the light receiving element (electronic component) 160 placed (mounted) on the second functional layer 43 of the laminated substrate 40 has both a light receiving surface 161 and a pair of connection terminals 162a, 162b formed on one vertical surface 160a perpendicular to one surface 43a of the second functional layer 43. That is, the connection terminals 162a, 162b are formed on both sides of the light receiving surface 161.

[0060] Further, the second functional layer 43 is formed with a second wiring 74a electrically connected to one connection terminal 162a of the light receiving element 160, and a second wiring 74b electrically connected to the other connection terminal 162b of the light receiving element 160. The second wirings 74a and 74b are partially exposed from the first functional layer 44 in the opening region of the component mounting hole 71.

[0061] Meanwhile, the first functional layer 44 also has formed thereon a first wiring 73a electrically connected to one connection terminal 162a of the light receiving element 160, and a first wiring 73b electrically connected to the other connection terminal 162b of the light receiving element 160. These first wirings 73a and 73b are formed so as to extend to positions facing the component mounting hole 71 on the side facing one vertical surface 160a of the light receiving element (electronic component) 160.

[0062] In this embodiment, one connection terminal 162a of the light receiving element (electronic component) 160 is electrically connected to both the first wiring 73a formed in the first functional layer 44 and the second wiring 74a formed in the second functional layer 43 via the conductive material 77.

[0063] Similarly, the other connection terminal 162b of the light receiving element (electronic component) 160 is electrically connected to both the first wiring 73b formed in the first functional layer 44 and the second wiring 74b formed in the second functional layer 43 via the conductive material 77.

[0064] The conductive material 77 is formed to fill the gap between the connection terminals 162a, 162b of the light-receiving element (electronic component) 160 extending in the stacking direction and the inner surface 71a of the component mounting hole 71, and at the bottom it contacts the second wirings 74a, 74b extending along one surface 43a of the second functional layer 43, and at the top it contacts and covers the wiring ends 73a1, 73b1 of the first wirings 73a, 73b extending along one surface 44a of the first functional layer 44, respectively.

[0065] In this way, even when the light-receiving surface 161 of the light-receiving element (electronic component) 160 and the pair of connection terminals 162a, 162b are both formed on the same surface (one vertical surface 160a), the continuity of the connection terminal 62a can be ensured by connecting one connection terminal 162a to both the first wiring 73a and the second wiring 74a, which are wirings having the same function, via the conductive material 77. Similarly, the continuity of the connection terminal 62b can be ensured by connecting one connection terminal 162b to both the first wiring 73b and the second wiring 74b, which are wirings having the same function, via the conductive material 77.

[0066] (Optical device: third embodiment) A light source unit (optical device) according to a third embodiment of the present invention will be described below. Note that the same components as those in the first embodiment are given the same reference numerals, and redundant description will be omitted. FIG. 8 is an enlarged perspective view of a main part showing a mounting portion of electronic components in the light source unit (optical device) of this embodiment.

[0067] In the light source unit (optical device) 210 of this embodiment, the wiring ends 73a1, 73b1 of the first wirings 73a, 73b formed in the first functional layer 44, which face the component mounting hole 71, are formed to be positioned outwardly recessed from the inner circumferential surface 71a of the component mounting hole 71. The distance Δt between the inner circumferential surface 71a of the component mounting hole 71 and each end face of the wiring ends 73a1, 73b1 may be in the range of 0.1 mm to 0.5 mm, for example.

[0068] With the configuration of this embodiment, when the connection terminal of the light receiving element is electrically connected to both the first wiring 73a, 73b and the second wiring using conductive material, a gap is created, particularly between the inner surface 71a of the component mounting hole 71 and the wiring ends 73a1, 73b1 of the first wiring 73a, 73b, respectively, which increases the contact area of ​​the conductive material and makes it possible to more firmly fix the conductive material to these connection areas.

[0069] (Optical device: fourth embodiment) A light source unit (optical device) according to a fourth embodiment of the present invention will be described below. Note that the same components as those in the first embodiment are given the same reference numerals, and redundant description will be omitted. Fig. 9 is an enlarged perspective view of a main part showing a portion where electronic components are mounted in the light source unit (optical device) of this embodiment, and Fig. 10 is a plan view showing the state of Fig. 9 with electronic components mounted thereon as viewed from above.

[0070] In the light source unit (optical device) 310 of this embodiment, electrode recesses 311a, 311b are formed on each of the wiring ends 73a1, 73b1 of the first wirings 73a, 73b formed in the first functional layer 44, which face the component mounting hole 71 and are continuous with the inner surface 71a of the component mounting hole 71 and extend along the stacking direction.

[0071] The electrode recesses 311a and 311b are, for example, semi-cylindrical cutouts, and are formed from the wiring end portions 73a1 and 73b1 of the first wirings 73a and 73b, respectively, to the first functional layer .

[0072] According to the configuration of this embodiment, when the connection terminals 362a, 362b of the light receiving element (electronic component) 360 are electrically connected to both the first wirings 73a, 73b and the second wirings by the conductive material 77, the contact area with the conductive material 77 is increased, thereby ensuring conductivity between the connection terminals 362a, 362b of the light receiving element (electronic component) 360 and the first wirings 73a, 73b and the second wirings, and preventing poor connection.

[0073] Furthermore, when the conductive material 77 is formed, the conductive material 77 also flows into these electrode recesses 311a, 311b, thereby making it possible to further ensure electrical continuity between the first wirings 73a, 73b and the second wiring.

[0074] (Optical device: fifth embodiment) A light source unit (optical device) according to a fifth embodiment of the present invention will be described below. Note that the same components as those in the first embodiment are given the same reference numerals, and redundant description will be omitted. Fig. 11 is an enlarged perspective view of a main part showing a portion where electronic components are mounted in the light source unit (optical device) of this embodiment. Fig. 12 is an enlarged perspective view of the main part in a state where electronic components are mounted in Fig. 11. Fig. 13 is an enlarged cross-sectional view of the main part along the stacking direction of the light source unit of this embodiment.

[0075] In the light source unit (optical device) 410 of this embodiment, the first wirings 73aA, 73bA formed on the first functional layer 44 are formed so as to face one surface 71a1 of the inner surface 71a of the component mounting hole 71, and the first wirings 73aB, 73bB are formed so as to face the other surface 71a2 of the inner surface 71a of the component mounting hole 71.

[0076] The first functional layer 44 is provided with interlayer connection wirings (via wirings) 75a1 and 75b1 that electrically connect the second wirings 74a and 74b formed in the second functional layer 43, which is the layer below the first functional layer 44, to the first wirings 73aA and 73bA on one side, respectively. Similarly, the first functional layer 44 is provided with interlayer connection wirings (via wirings) 75a2 and 75b2 that electrically connect the second wirings 74a and 74b to the first wirings 73aB and 73bB on the other side, respectively.

[0077] With this configuration, the first wiring 73aA and the first wiring 73aB are electrically connected via the second wiring 74a and function as a series of wirings with the same function. Also, the first wiring 73bA and the first wiring 73bB are electrically connected via the second wiring 74b and function as a series of wirings with the same function.

[0078] On the other hand, the light receiving element (electronic component) 460 of this embodiment has a light receiving surface 461 and connection terminals 462a1 and 462b1 formed on both sides of the light receiving surface 461 on one vertical surface 460a perpendicular to one surface 43a of the second functional layer 43. On the other hand, connection terminals 462a2 and 462b2 are formed on the other vertical surface 460b of the light receiving element (electronic component) 460. Of these, the connection terminals 462a1 and 462a2 are terminals connected to each other and have the same electrical function, and the connection terminals 462b1 and 462b2 are terminals connected to each other and have the same electrical function.

[0079] Furthermore, bumps 465a and 465b are formed on the second wirings 74a and 74b formed on the second functional layer 43 in areas exposed from the component mounting holes 71. These bumps 465a and 465b can be formed by stacking a conductive metal such as gold, silver, a solder alloy, or tungsten, which forms the first wirings 73aA and 73bA and the second wirings 74a and 74b.

[0080] Conductive material 77 is formed to connect connection terminal 462a1, first wiring 73aA, and second wiring 74a, and also to connect connection terminal 462a2, first wiring 73aB, and second wiring 74a. Similarly, conductive material 77 is formed to connect connection terminal 462b1, first wiring 73bA, and second wiring 74b, and also to connect connection terminal 462b2, first wiring 73bB, and second wiring 74b.

[0081] That is, in light receiving element (electronic component) 460, 462a1 and connection terminal 462a2, which have electrically identical functions, are connected to first wiring 73aA and second wiring 74a, and first wiring 73aB and second wiring 74a, respectively, via conductive material 77. Also, 462b1 and connection terminal 462b2, which have electrically identical functions, are connected to first wiring 73bA and second wiring 74b, and first wiring 73bB and second wiring 74b, respectively, via conductive material 77. The conductive materials 77 are also connected to conductive bumps 465a and 465b formed on the second wirings 74a and 74b, respectively.

[0082] In this manner, in this embodiment, by forming a plurality of connection terminals with the same electrical function on the light receiving element (electronic component) 460 and further forming each connection terminal across the first wiring and the second wiring, it is possible to prevent connection failures of the light receiving element (electronic component) 460 even more reliably than in the previously described embodiments.

[0083] Furthermore, in the light source unit (optical device) 410 of this embodiment, a component mounting recess 481 recessed in the thickness direction of the second functional layer 43 is formed in a region of the second functional layer 43 that is exposed from the component mounting hole 71 and that is sandwiched between the second wiring 74a and the second wiring 73b. A component fixing resin layer 482 that fills the interior of this component mounting recess 481 and comes into contact with the bottom of the light receiving element (electronic component) 460 is formed.

[0084] With this configuration, when mounting the light receiving element 460, the light receiving element 460 can be fixed to the second functional layer 43 by the component fixing resin layer 482, and then each connection terminal of the light receiving element 460 can be electrically connected to the first wiring and the second wiring by each conductive material 77, thereby improving workability when mounting the light receiving element 460 and making the mounting work easier.

[0085] (Electronic component mounting method) Next, a method for mounting electronic components when forming the light source unit (optical device) 10 of the first embodiment (FIGS. 1 to 5) will be described. When mounting an electronic component, such as a light receiving element 60, on a laminated substrate 40 before the electronic component is mounted, the light receiving element 60 is first positioned and placed at a predetermined position on one surface 43a of the second functional layer 43 exposed through the component mounting hole 71 formed in the first functional layer 44 (mounting process).

[0086] At this time, it is also preferable to fix the bottom surface of the light-receiving element 60 and the surface 43a of the second functional layer 43 exposed between the second wiring 74a and the second wiring 74b using a resin such as an adhesive. As the adhesive, for example, a so-called die-bond material such as an epoxy-based material can be used. Specifically, after dispensing the die-bond material (adhesive), the light-receiving element 60 is placed and temporarily fixed, and then a conductive resin (described later) is filled in and thermally cured.

[0087] Next, a conductive resin such as silver paste is filled to fill the gap between the connection terminal 62a of the light receiving element 60 and the inner surface 71a of the component mounting hole 71, thereby forming a conductive material 77 that electrically connects the connection terminal 62a to the first wiring 73a and the second wiring 74a (connection process).

[0088] Similarly, conductive resin is filled to fill the gap between the connection terminal 62b of the light receiving element 60 and the inner surface 71a of the component mounting hole 71, forming a conductive material 77 that electrically connects the connection terminal 62b to the first wiring 73b and the second wiring 74b (connection process).

[0089] In this way, by electrically connecting one connection terminal 62a to both the first wiring 73a and the second wiring 74a, which are wirings having the same function, via conductive material 77 filled with conductive resin and hardened, the continuity of connection terminal 62a can be ensured. Similarly, by electrically connecting one connection terminal 62b to both the first wiring 73b and the second wiring 74b, which are wirings having the same function, via conductive material 77 filled with conductive resin and hardened, the continuity of connection terminal 62b can be ensured.

[0090] Although one embodiment of the present invention has been described above, this embodiment is presented as an example and is not intended to limit the scope of the invention. This embodiment can be embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. This embodiment and its modifications are included within the scope and spirit of the invention, as well as within the scope of the invention and its equivalents as defined in the claims. [Explanation of symbols]

[0091] 10 Light source unit (optical device) 40 Laminated board 41~47 Functional layer 43 Second functional layer 44 1st functional layer 60 Photodetector (electronic component) 62a, 62b connection terminals 73a,73b 1st wiring 74a, 74b Second wiring 77 Conductive materials

Claims

1. An optical device having a laminated substrate on which a plurality of functional layers are laminated, and optical components and electronic components arranged on the laminated substrate, the functional layer has at least a first functional layer on which the optical component is mounted and a second functional layer disposed below the first functional layer and on which the electronic component is mounted; a first wiring is provided on one surface of the first functional layer, and a second wiring is provided on one surface of the second functional layer; an optical device in which the connection terminal of the electronic component is electrically connected to both the first wiring and the second wiring via a conductive material;

2. The optical device according to claim 1 , wherein the first wiring and the second wiring are electrically connected by an interlayer connection wiring provided on the laminated substrate.

3. The optical device according to claim 1 , wherein the first functional layer has a component mounting hole formed therein, the component mounting hole penetrating the first functional layer, and the electronic component is mounted in the component mounting hole.

4. 4. The optical device according to claim 3, wherein the conductive material is interposed between an inner peripheral surface of the component mounting hole and the connection terminal.

5. The optical device according to claim 3 , wherein the end of the first wiring is located at a position recessed from an inner circumferential surface of the component mounting hole.

6. The optical device according to claim 3 , wherein an electrode recess is formed adjacent to an end of the wiring of the first functional layer, the electrode recess being cut out in a direction that expands the component mounting hole.

7. An optical device described in any one of claims 3 to 6, wherein a component mounting recess recessed in the thickness direction is formed in the area of ​​the second functional layer exposed from the component mounting hole, and a component fixing resin layer is formed to fill the inside of the component mounting recess and contact at least the bottom of the electronic component.

8. The optical device according to claim 1 , wherein the conductive material is a conductive resin.

9. 9. The optical device according to claim 1, wherein the electronic component is a light receiving element, the optical component includes an optical waveguide, and the light receiving element is optically connected to receive at least a portion of the light propagating through the optical waveguide.

10. 1. A method for mounting an electronic component on a laminated substrate having at least a first functional layer having a first wiring provided on one surface thereof, a second functional layer disposed below the first functional layer and having a second wiring provided on one surface thereof, and a component mounting hole penetrating the first functional layer to expose one surface of the second functional layer, a mounting step of inserting the electronic component into the component mounting hole and positioning and mounting the electronic component on one surface of the second functional layer; a connecting step of providing a conductive material between one connection terminal of the electronic component and the first wiring and the second wiring to electrically connect them.

11. 11. The electronic component mounting method according to claim 10, wherein the connection step uses a conductive resin as the conductive material, and fills the space between the connection terminal and the inner surface of the component mounting hole with the conductive resin to electrically connect one connection terminal of the electronic component to the first wiring and the second wiring.

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