JP2019067807A - Light source module and manufacturing method thereof - Google Patents

Abstract

To provide a light source module excellent in earthquake resistance and heat resistance.SOLUTION: A light source module includes an optical semiconductor 10 having leads 11, a pedestal base 20 for connecting the optical semiconductor mechanically, and a wiring board 30 for connecting the optical semiconductor electrically. The pedestal base includes a body 23 including a first portion 21 for placing the optical semiconductor on the upper side, and having a first hole 25 through which the lead penetrates, and legs extending downward on both sides from the first portion. The wiring board includes a flexible board 40 separating downward from the first portion, and placed in a first space 5 formed between the legs, where a second hole 42 for passing the lead is formed, and a support board 50 for supporting the flexible board, having rigidity higher than that of the flexible board, and with a third hole 53 larger than the second hole formed in a region facing the second hole.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a light source module on which an optical semiconductor having a lead is mounted and a method of manufacturing the same.

  Patent Document 1 describes that a technique for improving the heat dissipation of a light source is provided. The light source module of Patent Document 1 includes a light emitting element, a stem supporting the light emitting element, and a light source having a terminal having one end electrically connected to the light emitting element, and the other end of the terminal electrically connected. It is described that a wiring board for electrically connecting to the external power supply terminal, and a heat diffusion member disposed between the stem and the wiring board and thermally connected to the light emitting element are provided.

JP, 2016-170905, A

  For example, in light source modules for automotive applications, not only heat dissipation, but also mechanical and electrical stability in a predetermined temperature range are required.

  One embodiment of the present invention is a light source module including an optical semiconductor having a lead, a pedestal for mechanically connecting the optical semiconductor, and a wiring substrate for electrically connecting the optical semiconductor. The pedestal includes a main body having a first portion on which an optical semiconductor is mounted on the upper side and having a first hole through which the lead passes, and legs extending downward from both sides of the first portion. The wiring board is disposed downward from the first portion, and is disposed in a first space formed between the legs, and further, a flexible in which a second hole through which the lead passes is formed. A support substrate supporting a flexible substrate and having a rigidity higher than that of the flexible substrate, wherein the support substrate is formed with a third hole larger than the second hole in a region opposed to the second hole. .

  According to the present disclosure, mechanical and electrical stability in a predetermined temperature range can be improved.

The figure which shows a mode that the light source module was seen from diagonally upward. The figure which shows a mode that the light source module was seen from diagonally downward. The figure which expand | deploys and shows a light source module to components. The top view of a light source module. Sectional drawing of the light source module in the VV line | wire of FIG. FIG. 6A is a view showing a part of the manufacturing process of the light source module, and FIG. 6A shows a state in which the optical semiconductor is mounted on the upper surface of the main body of the base and the pressing plate with four corners bent is attached; The figure which shows the state which attached the optical semiconductor to the base in the state which attached the four corners of the holding plate on the upper surface and made the holding plate parallel to the upper surface of the main body. Fig.7 (a) is a top view of a press board, FIG.7 (b) is a side view of a press board.

  FIG. 1 is a perspective view of a light source module 1 according to an embodiment of the present invention as viewed from above. Further, FIG. 2 is a perspective view of the light source module 1 as viewed from the lower side, and FIG. 3 is a developed view of the light source module 1 into respective parts. Further, FIG. 4 shows the light source module 1 in a plane viewed from the upper side, and FIG. 5 shows a cross section taken along the line V-V shown in FIG.

  The light source module 1 includes an optical semiconductor 10 having a lead 11, a pedestal 20 for mechanically connecting the optical semiconductor 10, and a wiring substrate 30 for electrically connecting the optical semiconductor 10. The pedestal 20 has a main body 23, and the main body 23 has a first portion 21 having a first hole 25 on which the optical semiconductor 10 is mounted on the surface 21 a of the upper side 2 and the lead 11 penetrates; And a pair of legs 22 extending from the portion 21 downward to both sides 3. The wiring board 30 is separated downward from the surface 21 b of the lower side 3 of the first portion 21 of the main body 23 and is formed in a space (first space) 5 formed between the pair of leg portions 22 on both sides. Is located in The wiring substrate 30 includes a flexible substrate 40 in which a second hole 42 through which the lead 11 penetrates is formed, and a support substrate 50 which supports the flexible substrate 40 on the upper side 2 and is higher in rigidity than the flexible substrate 40. The support substrate 50 further includes a third hole 53 which is larger than the second hole 42 and provided in a region facing the second hole 42 of the flexible substrate 40. The support substrate 50 may support the flexible substrate 40 on the lower side 3.

  In the present specification, the upper side (upper side) 2 indicates the direction in which the optical semiconductor 10 is mounted with respect to the main body 23 of the pedestal 20, and the lower side (lower side) 3 indicates the direction opposite to the upper side 2. Therefore, the upper side 2 and the lower side 3 may be vertical directions along the vertical direction, and the second direction opposite to the front, rear, left or right, or the appropriate first direction regardless of the vertical direction. It may be a combination of

  The main body 23 of the pedestal 20 mechanically mounts the optical semiconductor 10 on a heat dissipation substrate (heat sink) (not shown) or other support substrate, such as a support substrate for vehicle lights, and transfers heat from the optical semiconductor 10 to the heat dissipation substrate It may also include the function of heat dissipation, mechanical and thermal interface. The main body 23 of the pedestal 20 is formed of a material having high mechanical rigidity and also good thermal conductivity, such as metal, typically aluminum or an alloy containing a plurality of other components. The main body 23 of the pedestal 20 has a substantially rectangular shape as viewed from the upper side 2, in which a first portion 21 for mounting the optical semiconductor 10 and a second portion 27 for mounting the wiring substrate 30 are connected in the longitudinal direction 4 It has become.

  The main body 23 further includes a mechanical connection portion (joint portion) 24 protruding outward from the leg portion 22 on the lower side 3 of the leg portion 22 provided on both sides of the first portion 21 and is a pedestal for a heat sink or the like. Twenty main bodies 23 can be attached. The joint portion 24 is provided with a plurality of holes 24 a for attaching screws or rivets. A cross section in a direction orthogonal to the longitudinal direction 4 of the first portion 21 of the main body 23 of the pedestal 20 is substantially Ω-shaped or substantially inverted U-shaped including the first portion 21, the legs 22 on both sides and the projecting joint 24. The space 5 for installing the wiring board 30 is formed inside.

  The second portion 27 connected to the longitudinal direction 4 of the first portion 21 is a wide portion in which the length (width) in the direction orthogonal to the longitudinal direction 4 with respect to the first portion 21 is wide, This portion mainly supports the wiring board 30. The second portion 27 includes a notch 28 in which a connector 48 described later can be fitted, and mounting holes 29 provided on both sides of the notch 28. The wiring board 30 is inserted through the mounting hole 29 by screws 39 or rivets. It can be fixed to the main body 23.

  The upper surface 21a of the first portion 21 is provided with a mounting base 21c for forming a flat surface in a state of being slightly protruded from the surrounding surface in a circular shape, and the cap 12 and the stem are provided on the mounting base 21c. An optical semiconductor 10 of the can package type having a cylindrical shape is mounted. A first hole 25 through which the lead 11 penetrates is provided so as to penetrate the mounting table 21 c including the first portion 21, and in the optical semiconductor 10, the lead 11 passes through the first hole 25 and the stem It mounts so that the back surface of 13 may closely_contact | adhere to the mounting base 21c.

  The light source module 1 further includes a pressing plate 60 for fixing the optical semiconductor 10 to the upper surface 21 a of the first portion 21, specifically to the mounting table 21 c. The optical semiconductor 10 is fixed to the first portion 21 of the main body 23 of the pedestal 20 via the pressing plate 60 by screws 65 or rivets. The pressing plate 60 is substantially square, and includes a hole 61 provided at the center, through which the cap 12 of the optical semiconductor 10 passes, and a cylindrical pressing portion 62 provided around the hole 61. The pressing portion 62 is a circular or cylindrical portion protruding upward 2 from the pressing plate 60 so as to be engaged with the upper end of the stem 13. The pressing plate 60 further includes pressing holes 63 provided in each of the four corners 64, and a screw 65 or a rivet is attached to the pressing hole 63, and the four corners 64 are attached to the main body 23, specifically the first portion 21. . At this time, the four corners 64 of the pressing plate 60 may be attached so as to be substantially parallel to the first surface 21 a.

  The wiring substrate 30 attached to the lower side 3 of the pedestal 20 is generally T-shaped, is formed on the lower side 3 of the main body 23, and is a narrow portion disposed in the first space 5 extending in the longitudinal direction 4 31 and a wide portion 32 connected to the narrow portion 31. The wide portion 32 corresponds to the second portion 27 of the main body 23, and is provided in the vicinity of both ends of the wide second portion 27 of the main body 23 with mounting holes 33 provided near both ends of the wide portion 32. The wiring board 30 and the main body 23 can be fixed by the screws 39 or rivets using the provided mounting holes 29.

  A mounting hole 34 is also provided in the vicinity of the tip of the narrow portion 31 of the wiring substrate 30, that is, on the opposite side of the wide portion 32. A mounting hole 26 is provided in the first portion 21 of the main body 23 at a position opposite to the mounting hole 34. Using these mounting holes 34 and 26, the wiring board 30 is formed by screws 39 or rivets. And the main body 23 can be fixed. Therefore, the wiring board 30 and the main body 23 of the pedestal 20 are located at one end (attachment holes 34 and 26) at one end of the longitudinal direction 4 and at two places orthogonal to the other end (attachment holes 33 and 29). It is fixed in three places in total.

  The wiring substrate 30 has a two-layer structure of the same flexible substrate 40 and a support substrate 50, which has a substantially T-shaped peripheral shape. The flexible substrate 40 and the support substrate 50 are bonded by a heat resistant resin such as an epoxy resin, and the flexible substrate 40 is backed by the support substrate 50. The flexible substrate 40 may be entirely (entirely) lined by the support substrate 50, and in particular, the periphery of the hole (third hole) 53 of the support substrate 50 through which the lead 11 passes is lined It is also good.

  The support substrate 50 is made of a member that is higher in rigidity and higher in thermal conductivity than the flexible substrate 40, mechanically supports the flexible substrate 40, and also functions as a heat sink that emits heat from the flexible substrate 40. An example of the support substrate 50 is a substrate made of the same metal as the main body 23, for example, aluminum. The support substrate 50 may have a thermal expansion coefficient (linear expansion coefficient) substantially the same as that of the main body 23 so as to expand and contract in accordance with the thermal expansion of the main body 23. A metal substrate which is the same material as the main body 23 is suitable as the support substrate 50.

  The flexible substrate (flexible printed circuit board) 40 is a highly flexible circuit board in which a predetermined circuit 45 is formed in an insulating thin resin such as polyimide, and is an optical semiconductor connected to the narrow portion 31 of the flexible substrate 40 10 and the connector 48 mounted on the wide portion 32 of the flexible substrate 40 are electrically connected. A thermistor 49 for monitoring the temperature is mounted on the flexible substrate 40 near the tip of the narrow portion 31. The circuit 45 includes a circuit 45a for connecting the optical semiconductor 10 and the connector 48, the thermistor 49, and the like. And a circuit 45 b for connecting the connector 48. The circuit 45 a connecting the optical semiconductor 10 and the connector 48 includes a pair of electrodes 46 extending along the narrow portion 31 so as to correspond to the pair of leads 11 of the optical semiconductor 10. A hole (second hole) 42 through which the lead 11 of the optical semiconductor 10 passes is provided.

  Flexible substrate 40 and support substrate 50 include mounting holes 33 and 34 provided at the same position. On the other hand, the supporting substrate 50 is larger than the second hole 42 so as to surround the pair of second holes 42 at a position opposite to the pair of second holes 42 to which the leads 11 of the flexible substrate 40 are attached. Of the wide third holes 53 of the Therefore, the portion around the second hole 42 of the flexible substrate 40 overlapping the third hole 53 of the support substrate 50 is not backed by the support substrate 50, and a comparison is made within the range of the third hole 53. Softly deform (distort, bend). On the other hand, in the portion of the support substrate 50 excluding the third holes 53, the flexible substrate 40 is lined with the support substrate 50, has high rigidity, and is mechanically connected to the main body 23 with high strength. Accordingly, the joint portion between the flexible substrate 40 and the lead 11 has a structure having high mechanical strength as a whole, flexibility locally, and flexibility in the axial direction of the lead 11 in particular.

  The diameter of the third hole 53 provided in the support substrate 50 is desirably larger than the diameter of the solder fillet 43 formed when the lead 11 is soldered to the flexible substrate 40. Interference between the solder fillet 43 and the support substrate 50 can be prevented, and the flexibility of the flexible substrate 40 can be utilized.

  In addition, since the support substrate 50 is stretched and shrunk by the temperature almost in the same manner as the main body 23, the flexible substrate 40 backed by the support substrate 50 is also stretched and shrunk in combination with the main body 23 as a whole. Therefore, in the flexible substrate 40, the position of the second hole 42 through which the lead 11 penetrates and the position of the optical semiconductor 10 mounted on the main body 23 move substantially in the same manner as the temperature rises and falls. The thermal expansion coefficient (linear expansion coefficient) of the flexible substrate 40 is generally larger than that of the metal body 23 and stress is likely to occur between the lead 11 and the flexible substrate 40. By lining up, the movement of the flexible substrate 40 can be made to substantially coincide with the movement of the lead 11 in the radial direction due to temperature, and the generation of stress can be suppressed.

  As shown in FIG. 5 using a cross section, in the can package type optical semiconductor 10, the semiconductor element is mounted on the heat radiation base 18 disposed on the stem 13 and fixed by the sealing glass 19. A lead 11 projects from the bottom of the stem 13. In the light source module 1 of this example, the lead 11 as the connection terminal is inserted into the connection hole (second hole) 42 of the flexible substrate 40 and the solder fillet 43 is formed by soldering, and the support substrate 50 as the backing plate. A third hole 53 larger than the diameter of the solder fillet 43 is provided in the. Accordingly, inside the third hole 53, the flexible substrate 40 is a flexible thin film, and can be slightly moved in the axial direction of the lead 11 as the connection terminal. With this structure, to the sealing glass 19 by the linear expansion coefficient difference (thermal expansion coefficient difference, thermal expansion coefficient difference) between the main body 23 of the pedestal 20, the lead 11, the sealing glass 19, and the stem (heat radiation table) 13. Can be reduced, and damage to the optical semiconductor 10 due to thermal stress can be suppressed. Furthermore, since the movement of the tip end portion of the lead 11 in the radial direction can be suppressed by the flexible substrate 40, it is also possible to suppress the breakage of the sealing glass 19 due to the vibration.

  On the other hand, the flexible substrate 40 can be backed by the support substrate 50 while being flexible, and can be kept flat. Therefore, when the light source module 1 is manufactured, the positional relationship between the lead 11 and the second hole 42 for connection of the flexible substrate 40 can be set with high accuracy, and alignment becomes easy. For this reason, this structure is also effective for automatic assembly of the light source module 1.

  Furthermore, if the main body 23 of the pedestal 20 and the support substrate 50 of the backing are made of the same metal and have the same coefficient of linear expansion, the displacement due to the temperature change of the lead 11 in the radial direction is reduced. The stress to the glass stop 19 can be further reduced. Therefore, damage to the optical semiconductor 10 due to thermal stress can be further suppressed.

  In the can package type optical semiconductor 10 that requires hermetic sealing, the lead 11 is fixed by the sealing glass 19 so as to fill the gap with the stem 13 in the portion where the lead 11 which is the connection terminal protrudes. High reliability is required for the light source module 1 including the optical semiconductor 10, the pedestal 20 for fixing the same, and the wiring substrate 30 solder-connected to the optical semiconductor 10 with the main body 23 of the pedestal 20 in between. It is important to secure the airtightness by preventing damage to the sealing glass 19 against temperature guarantee range and vibration conditions, and to obtain a flexible substrate structure corresponding to assembly by an automatic machine, and adopt the above structure Thus, damage to the sealing glass 19 can be suppressed while adopting the flexible substrate 40.

  In FIG. 6, in the method of manufacturing the light source module 1, the step of mounting the optical semiconductor 10 with the screw 65 via the pressing plate 60 on the upper surface 21 a of the first portion 21 of the main body 23 of the pedestal 20 is extracted and shown. There is. The screw 65 may be a rivet.

As shown in FIG. 7, the presser plate 60 is a substantially square, cylindrical presser portion 62 provided at the center, through which the cap 12 penetrates, and a shape relating to the upper end of the stem 13 of the optical semiconductor 10. The four corners 64 are formed so as to be curved upward to the center, including the pressing portions 62 and the pressing holes 63 provided at the four corners 64. The distance (pitch) L between the pressing holes 63 and the amount of warpage S may satisfy the following condition (1).
0 <S <0.02 × L (1)

  As shown in FIG. 6A, in the process of manufacturing the light source module 1, when mounting the optical semiconductor 10 on the first surface 21a on the upper side of the first portion 21 of the main body 23 of the pedestal 20, four corners 64 are provided. Is attached to the holding plate 60 in a state in which the holding plate 60 is warped to the side opposite to the first surface 21a so that the cylindrical holding portion 62 passes through the cap 12 and the upper end protruding inward of the holding portion 62 .

  Next, as shown in FIG. 6 (b), when securing the optical semiconductor 10 to the main body 23 through the holding plate 60 by tightening the screw 65 inserted into the holding hole 63, the four corners 64 Screw 65 is tightened into body 23 until it is approximately parallel to surface 21 a of 1). When the four corners 64 of the cylindrical pressing portion 62 bent upward with respect to the first surface 21 a are deformed until they become parallel to the first surface 21 a, the cylindrical pressing portion 62 follows the lower side. It deforms while being pulled, and presses the upper end of the stem 13 downward substantially toward the main body 23 along the circumference. Therefore, the optical semiconductor 10 can be stably mounted on the upper first surface 21 a of the main body 23 by the pressing plate 60, and the stem 13 can be fixed in close contact with the main body 23.

  In recent years, in automotive applications, which is one of the important applications of the light source module 1 including the optical semiconductor 10, the use environment is different from general lamps, the environmental temperature and vibration conditions are severe, and materials of different linear expansion coefficients Countermeasures for damage due to combination and vibration were urgently needed. In addition, when assembling the light source module 1 including the reduction of the defect rate and the optical semiconductor 10, it is necessary to consider the safety of the eyes of the worker, so that the automatic assembly is essential, and the countermeasure is also necessary.

  In the light source module 1, the optical semiconductor 10 can be stably attached to the main body 23 of the pedestal 20 in a state in which the stem 13 and the main body 23 are in close contact with each other. Further, the main body 23 and the T-shaped wiring substrate 30 are provided with mounting holes 26 and 34, 29 and 33 provided at three positions sandwiching the second holes 42 for attaching the leads 11 to the wiring substrate 30 in the front and rear. Thus, the wiring board 30 can be stably attached to the main body 23 so as not to vibrate. Therefore, even under severe vibration conditions, the leads 11 of the optical semiconductor 10 and the wiring substrate 30 can be stably attached with relatively little movement.

  Furthermore, as the wiring substrate 30, the flexible substrate 40 backed by the support substrate 50 which is a reinforcing plate is adopted, and the support substrate 50 is removed from the region where the lead 11 of the optical semiconductor 10 is inserted. Solder connection is made in the movable region of the flexible substrate 40. For this reason, in the expansion and contraction in the axial direction due to the difference between the thermal expansion coefficients (linear expansion coefficients) of the main body 23 of the pedestal 20 and the leads 11, the region of the flexible substrate 40 from which the backing of the support substrate 50 is removed is in the axial direction It is flexibly stretched and absorbed. Therefore, the influence of the stress due to the difference in the thermal expansion coefficient can be suppressed on the sealing glass 19 to which the lead 11 is fixed. Furthermore, since the radial movement of the tip portion of the lead 11 is suppressed by the elasticity of the flexible substrate 40, it is possible to prevent the root destruction of the sealing glass 19 due to the vibration.

  Further, by backing the flexible substrate 40 with the support substrate 50 made of the same metal as the main body 23, it is possible to suppress the occurrence of stress due to the difference in the coefficient of thermal expansion in the radial direction of the lead 11. Furthermore, by backing the flexible substrate 40 with the support substrate 50 having high heat dissipation, it becomes easy to dissipate the heat generated in the optical semiconductor 10 through the leads 11. Therefore, it is possible to provide the light source module 1 which has good heat dissipation, can stably exhibit performance in a wide temperature range, and has high vibration resistance.

  Furthermore, since the flexible substrate 40 is lined with the support substrate 50, the position of the second hole 42 of the flexible substrate 40 into which the lead 11 is inserted can be stably held at the time of manufacture, and the assembly by an automatic machine The light source module 1 which can respond can be provided.

DESCRIPTION OF SYMBOLS 1 light source module 10 optical semiconductor, 11 lead, 12 cap, 13 stem 20 pedestal, 21 1st part which mounts optical semiconductor, 22 leg parts, 23 main body 30 wiring board, 40 flexible substrate, 45a circuit, 45b circuit,
50 support substrate 60 pressure plate, 61 holes, 62 pressure portions

Claims (9)

An optical semiconductor having a lead;
A pedestal mechanically connecting the optical semiconductor;
And a wiring substrate for electrically connecting the optical semiconductor,
The base has a main body provided with a first portion on which the optical semiconductor is mounted on the upper side and having a first hole through which the lead passes, and a leg extending downward from both sides of the first portion. Including
The wiring board is disposed below the first portion and in a first space formed between the legs.
A flexible substrate formed with a second hole through which the lead passes;
A supporting substrate which supports the flexible substrate and has a rigidity higher than that of the flexible substrate, wherein a third hole larger than the second hole is formed in a region facing the second hole; Including, light source module. In claim 1,
The wiring substrate includes a narrow portion disposed in the first space, and a wide portion connected to the narrow portion.
The body includes a second portion corresponding to both ends of the wide portion,
The light source module, wherein the wiring substrate is fixed to the main body in at least three places of the vicinity of the tip of the narrow portion and the first portion and the vicinity of both ends of the wide portion and the second portion. . In claim 1 or 2,
The light source module, wherein the flexible substrate and the support substrate are T-shaped. In any one of claims 1 to 3,
The light source module, wherein the support substrate has a thermal conductivity higher than that of the flexible substrate. In any one of claims 1 to 4,
The thermal expansion coefficient of the support substrate is substantially the same as the thermal expansion coefficient of the main body, and the flexible substrate is backed by the support substrate at least around the third hole. In claim 5,
The light source module, wherein the support substrate is a substrate of the same material as the main body. In any one of claims 1 to 6, further,
A light source module, comprising a pressing plate for fixing the optical semiconductor to an upper first surface of the first portion via a screw or a rivet. In claim 7, further,
The optical semiconductor includes a cap and a stem,
The pressing plate is a substantially square cylindrical pressing portion provided at the center, and the pressing portion penetrates the cap, and the pressing portion relates to the upper end of the stem;
A light source module, comprising: pressing holes through which the screws or rivets are provided at four corners of the pressing plate, and the four corners are attached to the main body substantially parallel to the first surface by the screws or rivets. A method of manufacturing a light source module according to any one of claims 1 to 6, wherein
The light source module further includes a pressing plate that fixes the optical semiconductor to a first upper surface of the first portion via a screw or a rivet.
The optical semiconductor includes a cap and a stem,
The pressing plate is a substantially square tubular pressing portion provided at the center, through which the cap passes, and the pressing portion associated with the upper end of the stem;
And holding holes for passing the screws or rivets provided at four corners of the holding plate;
In the manufacturing method, when the optical semiconductor is mounted on the first portion of the main body, the main body of the main body with the screws or rivets has the four corners bent back to the side opposite to the first surface. And fixing the four corners substantially parallel to the first surface.

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