JP2024089718A - Light source device and vehicle lamp - Google Patents

Abstract

A light source device and a vehicle lamp are provided that are capable of suppressing the influence of heat generated when a light emitting element is driven on other electronic components.
[Solution] The light-emitting module has a substrate consisting of a second substrate portion having high thermal conductivity and integrated with a first substrate portion, a plurality of light-emitting elements arranged on the surface of the second substrate portion on one main surface of the substrate, and a sealing portion made of resin formed on the second substrate portion to seal the plurality of light-emitting elements, and the substrate is formed with a first wiring pattern including two wirings each arranged to straddle the first substrate portion and the second substrate portion at each of two corners that sandwich one side of a through hole on one main surface of the substrate and supplying power to at least one of the plurality of light-emitting elements, and a second wiring pattern including a wiring arranged to straddle the first substrate portion and the second substrate portion at a portion between the two corners of one side and supplying power to at least one of the plurality of light-emitting elements.
[Selected figure] Figure 3

Description

The present invention relates to a light source device and a vehicle lamp.

A light source device for use in vehicle lighting fixtures is disclosed. For example, Patent Document 1 discloses a vehicle lighting device having a light-emitting module in which light-emitting elements and electronic components for driving the light-emitting elements are arranged on the surface of a substrate, and a socket provided in contact with the underside of the substrate and equipped with fins for dissipating heat generated in the light-emitting module to the outside.

Patent document 2 also discloses a light source unit for vehicle lighting that includes a circuit board that is partially made of a heat transfer member and has wiring formed across the heat transfer member and elements other than the heat transfer member, a light emitting element disposed on the surface of the heat transfer member, and a sealing member made of resin that seals the light emitting element.

JP 2020-91994 A JP 2022-82076 A

One of the problems with the vehicle lighting device disclosed in Patent Document 1 is that heat generated when the light-emitting elements are driven is transferred through the substrate to the electronic components, causing the electronic components to overheat.

In addition, in the light source unit for vehicle lighting disclosed in Patent Document 2, when the resin that becomes the sealing member is thermally cured during manufacturing, the heat transfer member is deformed due to stress caused by the contraction of the resin, and one of the problems is that the wiring formed across the heat transfer member and parts other than the heat transfer member is broken.

The present invention has been made in consideration of the above points, and aims to provide a light source device and vehicle lamp that can prevent wiring breaks during manufacturing while suppressing the influence of heat generated when the light-emitting element is driven on other electronic components.

The light source device according to the present invention comprises a substrate including a first substrate portion having a through hole with a rectangular planar shape and a second substrate portion provided within the through hole so as to close the through hole and integrated with the first substrate portion, the second substrate portion having a higher thermal conductivity than the first substrate portion, a plurality of light-emitting elements arranged on a surface of the second substrate portion on one main surface of the substrate, and a sealing portion made of resin formed on the second substrate portion on one main surface of the substrate and sealing the plurality of light-emitting elements, and a light-emitting module having a sealing portion made of resin formed on the second substrate portion on the other main surface of the substrate of the light-emitting module. and a heat sink bonded to the second substrate portion, and the substrate is provided with a first wiring pattern including two wirings each arranged to straddle the first substrate portion and the second substrate portion at each of two corners sandwiching one side of the through hole on one main surface of the substrate, and supplying power to at least one of the plurality of light-emitting elements, and a second wiring pattern including a wiring arranged to straddle the first substrate portion and the second substrate portion at a portion between the two corners of the first side, and supplying power to at least one of the plurality of light-emitting elements.

1 is a perspective view showing a configuration of a light source device according to a first embodiment. FIG. 2 is an exploded perspective view showing the configuration of the light source device according to the first embodiment. FIG. 2 is an enlarged plan view of a portion of the light source device according to the first embodiment. 1 is a cross-sectional view of a light source device according to a first embodiment. 1 is a side view of a vehicle lamp as an example of use of a light source device according to a first embodiment.

The following describes in detail an embodiment of the present invention with reference to the drawings. Note that the same components in the drawings are given the same reference numerals, and descriptions of duplicated components are omitted.

The configuration of the light source device 100 according to the first embodiment will be described with reference to Figs. 1 and 2. Fig. 1 is a perspective view showing the configuration of the light source device 100 according to the first embodiment. Fig. 2 is an exploded perspective view showing the configuration of the light source device 100.

In Fig. 1 and Fig. 2, for ease of explanation, the XYZ axes are defined as the lengthwise axis (front-back direction) of the light source device 100 as the X axis, the widthwise axis (left-right direction) of the light source device 100 as the Y axis, and the heightwise axis (up-down direction) of the light source device 100 as the Z axis.

[Outline of light source device 100]
The light source device 100 includes a light emitting module 110 including a light emitting device, a housing holder 120 for housing the light emitting module 110, a heat sink 130 for dissipating heat generated in the light emitting module 110 to the outside, and a power supply connector 140 (see FIG. 2) for providing an electrical connection for supplying power from an external power source to the light emitting module 110.

[Light-emitting module 110]
First, a description will be given of the configuration of the light emitting module 110. The light emitting module 110 is composed of a substrate 11, and a light emitting device 12 and a driving element 13 provided on one of the main surfaces (front surface) of the substrate 11.

The substrate 11 is a plate-like body consisting of a first substrate portion 14 and a second substrate portion 15.

The first substrate portion 14 of the substrate 11 is an insulating portion having a substantially circular planar shape. The first substrate portion 14 has a through hole 14H in the center that has a rectangular planar shape and passes through the first substrate portion 14 in the lengthwise direction. The first substrate portion 14 is, for example, a multi-layer glass epoxy substrate (FR-4).

The second substrate portion 15 of the substrate 11 has a rectangular planar shape, is disposed in the through hole 14H with the same thickness as the first substrate portion 14, and is an insulating portion that is integrated with the first substrate portion 14. In other words, the second substrate portion 15 is provided so as to block the through hole 14H of the first substrate portion 14.

The second substrate portion 15 is made of a material with a higher thermal conductivity than the first substrate portion 14. For example, the second substrate portion 15 is an aluminum nitride (AlN) substrate with a thermal conductivity of 180 to 200 W/m·K, which is higher than the thermal conductivity of the glass epoxy substrate (first substrate portion 14) with a thermal conductivity of 0.25 to 0.45 W/m·K.

The light-emitting device 12 is provided on the front surface of the second substrate portion 15 and is configured to include a plurality of light-emitting elements. The specific configuration of the light-emitting device 12 will be described later.

The driving element 13 is provided on the front surface of the first substrate portion 14 and is an element used to drive each of the multiple light-emitting elements in the light-emitting device 12 using a signal from an external device, such as an integrated circuit (IC), a protective element, a capacitor, or a resistor.

Note that in Figures 1 and 2, the driving element 13 is merely shown diagrammatically to indicate that the driving element 13 is provided on the front surface of the first substrate portion 14, and the arrangement of the driving element 13 can be designed as appropriate.

In addition, on the front surface of the first substrate portion 14 and the second substrate portion 15, wiring is provided to connect to each of the multiple light-emitting elements to supply power, and wiring is provided to electrically connect each of the multiple light-emitting elements to the driving element 13, but these are omitted in Figures 1 and 2. The wiring provided on the top surface of the second substrate portion 15 and the surrounding top surface of the first substrate portion 14 will be described later.

[Storage holder 120]
Next, a description will be given of the configuration of the housing holder 120. The housing holder 120 is configured such that a base portion 17, a cylindrical wall portion 18, a module housing portion 19, and a socket portion 21 are integrated together.

The base portion 17 is a plate-like portion with a roughly circular planar shape.

The tube wall portion 18 is a cylindrical portion that protrudes forward from approximately the center of the front surface of the base portion 17. The tube wall portion 18 has four claw portions 18C that are spaced apart along the outer circumferential surface of the tube wall portion 18 and protrude from the outer circumferential surface in the height direction and width direction.

The module housing section 19 is a disk-shaped portion that is arranged to close the inside of the tube wall section 18 in a plan view. The module housing section 19 forms a housing space that houses the light-emitting module 110 by a front surface 19S of the module housing section 19 and the inner peripheral surface of the tube wall section 18 forward of the front surface 19S.

The module housing section 19 has a through hole 19H1 with a rectangular planar shape that passes through the module housing section 19 together with the base section 17 in the lengthwise direction, and a through hole 19H2 with a rectangular planar shape that is provided below the through hole 19H1 and passes through the module housing section 19 together with the base section 17 in the lengthwise direction. In a plan view, the through hole 19H2 is smaller in size than the through hole 19H1.

The socket portion 21 is a cylindrical portion that surrounds the through hole 19H2 on the rear surface of the base portion 17 and protrudes rearward from the rear surface of the base portion 17.

The storage holder 120 is made of an insulating resin material such as polyethylene terephthalate (PET), polybutylene terephthalate (PBT), or polyamide (PA). The storage holder 120 may be made of resin to which a filler with high thermal conductivity, such as ceramic, metal, or carbon black, has been added.

The O-ring 22, which has a circular planar shape, is attached to the housing holder 120 so as to be disposed along the outer circumferential surface of the cylindrical wall portion 18 and in contact with the front surface of the base portion 17. The O-ring 22 is a packing made of an elastic material such as rubber or silicone resin.

[Heat radiator 130]
Next, a description will be given of the configuration of the heat sink 130. The heat sink 130 is configured such that a base portion 24, a heat receiving portion 25, and heat sink fins 26 are integrated together.

The base portion 24 is a plate-like portion with a roughly circular planar shape.

The heat receiving section 25 is a generally rectangular parallelepiped portion that protrudes forward from approximately the center of the front surface of the base section 24. The front surface 25S of the heat receiving section 25 is a heat receiving surface that receives heat generated in the light emitting module 110.

The heat dissipation fins 26 are plate-shaped parts that protrude rearward from the rear surface of the base portion 24 and are arranged in a row in the width direction.

The heat sink 130 is made of a metal with high thermal conductivity, such as aluminum (Al), iron (Fe), or copper (Cu). As with the housing holder 120, the heat sink 130 can also be made of a resin material with improved thermal conductivity, such as PET, PBT, or PA, with the addition of a filler with high thermal conductivity, such as ceramic, metal, or carbon black, to an insulating resin material.

[Power supply connector 140]
Next, a description will be given of the configuration of the power supply connector 140. The power supply connector 140 is composed of an insulating main body 31 and a plurality of metallic lead terminals 32 that are fixed to the main body 31 while penetrating the main body 31 in the length direction and that are each provided in a row in the width direction.

Here, the combination of the light emitting module 110, the storage holder 120, the heat sink 130, and the power supply connector 140 will be described. The storage holder 120 and the heat sink 130 described above have a structure that can be integrated by insert molding the storage holder 120 and the heat sink 130. Specifically, the storage holder 120 and the heat sink 130 are fixed in a state in which the rear surface of the base portion 17 of the storage holder 120 and the front surface of the base portion 24 of the heat sink 130 face each other by fitting the heat receiving portion 25 of the heat sink 130 into the through hole 19H1 of the storage holder 120.

In addition, by integrating the housing holder 120 and the heat sink 130, the front surface 19S of the module housing section 19 and the front surface 25S of the heat receiving section 25 are arranged on the same plane. A seal material 28 made of resin is provided at the interface between the front surface 19S of the module housing section 19 and the front surface 25S of the heat receiving section 25 to ensure airtightness of the interface.

When the housing holder 120 and the heat sink 130 are integrated, the substrate 11 of the light emitting module 110 is attached to the front surface 25S of the heat receiving portion 25 of the heat sink 130 via a thermally conductive adhesive 29. In other words, the heat sink 130 is thermally connected to the light emitting module 110. The thermally conductive adhesive 29 is made of silicone resin containing, for example, alumina (Al ₂ O ₃ ) particles and flake graphite filler.

The main body 31 of the power supply connector 140 is inserted and fixed in the through hole 19H2 of the housing holder 120. By fixing the main body 31 of the power supply connector 140 in the through hole 19H2, the lead terminals 32 of the power supply connector 140 protrude from the front surface 19S of the module housing section 19 and the rear surface of the base section 17.

Each of the lead terminals 32 protruding from the front surface 19S of the module housing section 19 is inserted so as to pass through a terminal hole (not shown) provided in the first substrate portion 14 of the substrate 11 of the light-emitting module 110, and is fixed by soldering to the front surface of the first substrate portion 14. This joining electrically connects each of the lead terminals 32 to wiring (not shown) formed on the front surface of the first substrate portion 14.

In addition, each of the lead terminals 32 protruding from the rear surface of the base portion 17 is disposed within the socket portion 21 of the housing holder 120. The socket portion 21 containing the lead terminals 32 can be connected to, for example, an electrical plug provided on an external power source. Therefore, the light source device 100 is driven by supplying power from the external power source to the substrate 11 of the light-emitting module 110 via the lead terminals 32.

[Detailed configuration of the light emitting device and the vicinity of the light emitting device]
Here, a detailed configuration of the light emitting device 12 and the vicinity of the light emitting device 12 will be described with reference to Fig. 3 and Fig. 4. Fig. 3 is a plan view showing part A including the second substrate portion 15 of the light emitting module 110 in Fig. 1. Fig. 4 is a cross-sectional view taken along line 4-4 in Fig. 3.

In the following, to avoid complicating the explanation, the direction perpendicular to the substrate 11 will be described as the up-down direction. For example, the "front surface" of the substrate 11 in Figs. 1 and 2 will be described as the "top surface" of the substrate 11 in Figs. 3 and 4.

In addition, in FIG. 3, the sealing portion 52 shown in FIG. 4 has been omitted to avoid cluttering the illustration. In addition, in FIG. 3, the center line of the upper surface of the second substrate portion 15 that is parallel to a pair of opposing sides of the second substrate portion 15 is shown as center line CL1, and the center line of the upper surface of the second substrate portion 15 that intersects perpendicularly to center line CL1 is shown as center line CL2.

First, the detailed configuration of the substrate 11 on which the light emitting device 12 is arranged will be described. As described above, the substrate 11 is configured by integrating the first substrate portion 14 and the second substrate portion 15. Specifically, the first substrate portion 14 and the second substrate portion 15 are joined to each other by an adhesive layer 35 provided between the through hole 14H of the first substrate portion 14 and the second substrate portion 15.

The adhesive layer 35 is made of, for example, an insulating prepreg (epoxy resin containing glass fibers) that is used to laminate the core layers when manufacturing the first substrate portion 14 (glass epoxy substrate). Therefore, the first substrate portion 14 and the second substrate portion 15 are integrated and insulated from each other via the adhesive layer 35.

By providing the adhesive layer 35 between the first substrate portion 14 and the second substrate portion 15 in this manner, when heat generated during operation of the light-emitting element in the light-emitting device 12 is transmitted to the second substrate portion 15, the heat is less likely to be transmitted to the first substrate portion 14. In other words, it is possible to prevent the heat generated during operation of the light-emitting element from being transmitted to the driving element 13 provided on the upper surface of the first substrate portion 14.

A thermal diffusion film 37 made of a metal with high thermal conductivity, such as Cu, is formed on the underside of the substrate 11. The thermal diffusion film 37 covers the entire underside of the second substrate portion 15 and reaches the underside of the first substrate portion 14, with its outer edge formed along the outer edge of the through hole 14H. In other words, the thermal diffusion film 37 is formed slightly larger than the through hole 14H while blocking the through hole 14H in a plan view seen from a direction perpendicular to the underside of the substrate 11.

In other words, the thermal diffusion film 37 is formed only near the outer edge of the through hole 14H on the underside of the first substrate portion 14, and is not formed on most of the underside of the first substrate portion 14. Therefore, the thermal diffusion film 37 is hardly in contact with the first substrate portion 14, and there is almost no direct transfer of heat from the thermal diffusion film 37 to the first substrate portion 14.

Since the thermal diffusion film 37 is formed in this manner, when heat generated during operation of the light-emitting element in the light-emitting device 12 is transmitted to the thermal diffusion film 37 via the second substrate portion 15, the heat can be diffused toward the heat sink 130 while preventing the heat from being directly transmitted from the thermal diffusion film 37 to the first substrate portion 14. In other words, the thermal diffusion film 37 functions as a heat spreader.

The thermal diffusion film 37 also functions as a joint reinforcement material that increases the fixing strength between the first substrate portion 14 and the second substrate portion 15 during the manufacture of the light-emitting module 110.

As described above, the substrate 11 of the light-emitting module 110 is joined to the upper surface 25S of the heat-receiving portion 25 of the heat sink 130 via the thermally conductive adhesive 29. Therefore, the heat generated when the light-emitting element in the light-emitting device 12 is driven is dissipated by the heat sink 130 via the second substrate portion 15, the thermal diffusion film 37, and the thermally conductive adhesive 29.

Next, the detailed configuration of the light emitting device 12 will be described. The light emitting device 12 is composed of a first light emitting element 41 to a sixth light emitting element 46 arranged on the upper surface of the second substrate portion 15, a frame body 51 that surrounds each of the first light emitting element 41 to the sixth light emitting element 46, and a sealing portion 52 that seals each of the first light emitting element 41 to the sixth light emitting element 46.

The first light-emitting element 41 to the sixth light-emitting element 46 each have a rectangular planar shape, and the first light-emitting element 41 and the fourth light-emitting element 44, the second light-emitting element 42 and the third light-emitting element 43, and the fifth light-emitting element 45 and the sixth light-emitting element 46 are arranged so as to face each other at equal intervals from the center line CL1, with the center line CL1 in between.

That is, the first light-emitting element 41 and the fourth light-emitting element 44, the second light-emitting element 42 and the third light-emitting element 43, and the fifth light-emitting element 45 and the sixth light-emitting element 46 are each arranged so as to be linearly symmetrical with respect to the center line CL1.

The fifth light-emitting element 45 and the sixth light-emitting element 46 are arranged inward from the first light-emitting element 41 to the fourth light-emitting element 44 in a plan view and toward the center of the second substrate portion 15. The fifth light-emitting element 45 and the sixth light-emitting element 46 are smaller in size from a plan view than the first light-emitting element 41 to the fourth light-emitting element 44.

The first light-emitting element 41 to the sixth light-emitting element 46 are light-emitting diodes (LEDs) made of semiconductor layers including a light-emitting layer that emits light having a red wavelength. Each of the first light-emitting element 41 to the sixth light-emitting element 46 emits the red light emitted from the light-emitting layer from the top surface.

The frame 51 has an annular shape in a plan view, and is a cylindrical member surrounding each of the first light-emitting element 41 to the sixth light-emitting element 46 on the upper surface of the second substrate portion 15. The frame 51 has light reflectivity that reflects red light emitted from each of the first light-emitting element 41 to the sixth light-emitting element 46. The frame 51 is made of, for example, a silicone resin containing titanium oxide (TiO ₂ ).

The sealing portion 52 is a dome-shaped transparent sealing member that protrudes upward from the inside of the frame body 51 on the upper surface of the second substrate portion 15. The sealing portion 52 seals the first light-emitting element 41 to the sixth light-emitting element 46, as well as the wiring and wires arranged on the second substrate portion 15 to electrically connect them, in the space above the second substrate portion 15 inside the frame body 51.

The sealing portion 52 is made of a material, such as silicone resin, that is translucent to the red light emitted from each of the first light-emitting element 41 to the sixth light-emitting element 46. The shape of the sealing portion 52 does not have to be dome-shaped, and may have, for example, a flat surface parallel to the upper surface of the second substrate portion 15.

Next, the configuration of the wiring connected to each of the first light-emitting element 41 to the sixth light-emitting element 46 will be described. Hereafter, as shown in FIG. 3, the left and right sides of the top surface of the second substrate portion 15 will be referred to as sides 15YA and 15YB, respectively, and the top and bottom sides will be referred to as sides 15ZA and 15ZB, respectively. Also, area A shown in FIG. 3 will be divided into four areas by center lines CL1 and CL2, and the four areas will be described as a first section in which the first light-emitting element 41 is placed, a second section in which the second light-emitting element 42 is placed, a third section in which the third light-emitting element 43 is placed, and a fourth section in which the fourth light-emitting element 44 is placed.

On the upper surface of the second substrate portion 15 and the surrounding upper surface of the first substrate portion 14, the first wiring 61 to the eighth wiring 68 are formed, separated from each other by a distance that will not cause short circuits, and each wiring is made of highly electrically conductive copper (Cu) material with a gold (Au) plating applied to the surface.

The first wiring 61 extends across the first substrate portion 14 and the second substrate portion 15, covering the corner C1 of the second substrate portion 15 formed by the sides 15YA and 15ZB and its surrounding area. In other words, the first wiring 61 covers most of the first section, including the corner C1. The first wiring 61 is joined to a bottom electrode (not shown) provided on the bottom surface of the second light-emitting element 42.

The first wiring 61 is connected to one end of a bonding wire W, the other end of which is connected to an upper electrode (not shown) provided on the upper surface of the first light-emitting element 41. In other words, the first wiring 61 is electrically connected to the first light-emitting element 41 via the bonding wire W. For example, the bonding wire W is an Au wire.

The second wiring 62 extends across the first substrate portion 14 and the second substrate portion 15 while covering the corner C2 of the second substrate portion 15 formed by the side 15YB and the side 15ZB and its surrounding area. In other words, the second wiring 62 covers most of the second section, including the corner C2.

The second wiring 62 is connected to one end of a bonding wire W, the other end of which is connected to an upper surface electrode (not shown) arranged on the upper surface of the second light-emitting element 42. In other words, the second wiring 62 is electrically connected to the second light-emitting element 42 via the bonding wire W.

The third wiring 63 extends across the first substrate portion 14 and the second substrate portion 15, covering the corner C3 of the second substrate portion 15 formed by the sides 15YB and 15ZA and its surrounding area. The third wiring 63 is joined to a lower electrode (not shown) arranged on the lower surface of the fourth light-emitting element 44. In other words, the third wiring 63 covers most of the third section, including the corner C3.

The third wiring 63 is connected to one end of a bonding wire W, the other end of which is connected to an upper electrode (not shown) arranged on the upper surface of the third light-emitting element 43. In other words, the third wiring 63 is electrically connected to the third light-emitting element 43 via the bonding wire W.

The fourth wiring 64 extends across the first substrate portion 14 and the second substrate portion 15 while covering the corner C4 of the second substrate portion 15 formed by the sides 15YA and 15ZA and its surrounding area. In other words, the fourth wiring 64 covers most of the fourth section, including the corner C4.

The first wiring 61, second wiring 62, third wiring 63, and fourth wiring 64 each preferably cover at least 1/3 of each corner of the sides that make up corners C1, C2, C3, and C4 of each section (the lower half of side 15YA and the left half of side 15ZB, the right half of side 15ZB and the lower half of side 15YB, the upper half of side 15YB and the right half of side 15ZA, and the left half of side 15ZA and the upper half of side 15YA). It is preferable that they cover at least 1/2.

The fourth wiring 64 is connected to one end of a bonding wire W, the other end of which is connected to an upper surface electrode (not shown) arranged on the upper surface of the fourth light-emitting element 44. In other words, the fourth wiring 64 is electrically connected to the fourth light-emitting element 44 via the bonding wire W.

The fifth wiring 65 extends between the first wiring 61 and the fourth wiring 64 along the center line CL1, and straddles the first substrate portion 14 and the second substrate portion 15. In other words, the fifth wiring 65 is arranged straddling the side 15YA along the perpendicular bisector of the side 15YA. The fifth wiring 65 is joined to a lower electrode (not shown) arranged on the lower surface of the first light-emitting element 41. In other words, the fifth wiring 65 covers about 1/4 of the first section along the center line CL1.

The sixth wiring 66 extends between the second wiring 62 and the third wiring 63 along the center line CL1, and straddles the first substrate portion 14 and the second substrate portion 15. In other words, the sixth wiring 66 is arranged straddling the side 15YB along the perpendicular bisector of the side 15YB. The sixth wiring 66 is joined to a lower electrode (not shown) arranged on the lower surface of the third light-emitting element 43. The sixth wiring 66 is also electrically connected to the second wiring 62 via an internal wiring (not shown) provided inside the first substrate portion 14. In other words, the sixth wiring 66 covers about 1/4 of the third section along the center line CL1.

The fifth wiring 65 and the sixth wiring 66 are provided with a narrower width than each of the first wiring 61 to the fourth wiring 64. In other words, the first wiring 61 to the fourth wiring 64, which are larger in size in a plan view than the fifth wiring 65 and the sixth wiring 66, are respectively arranged at the corners C1 to C4 of the second substrate portion 15 and their respective peripheral areas.

As described above, the fifth wiring 65 is electrically connected to the first light-emitting element 41, the first wiring 61 is electrically connected to the first light-emitting element 41 and the second light-emitting element 42, the second wiring 62 is electrically connected to the second light-emitting element 42 and the sixth wiring 66, the sixth wiring 66 is electrically connected to the third light-emitting element 43, the third wiring 63 is electrically connected to the third light-emitting element 43 and the fourth light-emitting element 44, and the fourth wiring 64 is electrically connected to the fourth light-emitting element 44.

Therefore, the first wiring 61 to the sixth wiring 66 as the first wiring pattern electrically connect each of the first light-emitting element 41 to the fourth light-emitting element 44 in series. That is, the fifth wiring 65 serves as one end of the series connection of the first light-emitting element 41 to the fourth light-emitting element 44, and the fourth wiring 64 serves as the other end of the series connection.

The seventh wiring 67 extends between the second wiring 62 and the sixth wiring 66, stretching along the center line CL1 and straddling the first substrate portion 14 and the second substrate portion 15. In other words, the seventh wiring 67 is arranged straddling side 15YB along the perpendicular bisector of side 15YB. That is, the seventh wiring 67 covers a small portion of the second section along the center line CL1.

The seventh wiring 67 is formed to be narrower than each of the first wiring 61 to the sixth wiring 66. In addition, the seventh wiring 67 is joined to a lower electrode (not shown) arranged on the lower surface of the fifth light-emitting element 45.

The eighth wiring 68 extends between the second wiring 62 and the sixth wiring 66, extending along the center line CL1 so as to be adjacent to the seventh wiring 67, and straddling the first substrate portion 14 and the second substrate portion 15. In other words, the eighth wiring 68 is arranged straddling side 15YB along the perpendicular bisector of side 15YB. That is, the eighth wiring 68 covers a small portion of the third section along the center line CL1.

The eighth wiring 68 is formed to be narrower than each of the first wiring 61 to the sixth wiring 66. The eighth wiring 68 is also joined to a lower electrode (not shown) arranged on the lower surface of the sixth light-emitting element 46.

The fourth wiring 64 described above is connected to one end of a bonding wire W, the other end of which is joined to a top electrode (not shown) arranged on the top surface of the fifth light-emitting element 45, and the other end of a bonding wire W, the other end of which is joined to a top electrode (not shown) arranged on the top surface of the sixth light-emitting element 46. That is, the fourth wiring 64 is electrically connected to the fifth light-emitting element 45 and the sixth light-emitting element 46 via the bonding wire W.

As described above, the seventh wiring 67 is electrically connected to the fifth light-emitting element 45, and the fourth wiring 64 is electrically connected to the fifth light-emitting element 45. In addition, the eighth wiring 68 is electrically connected to the sixth light-emitting element 46, and the fourth wiring 64 is electrically connected to the sixth light-emitting element 46. A common voltage is applied to the seventh wiring 67 and the eighth wiring 68. Therefore, the seventh wiring 67 and the eighth wiring 68 as the second wiring pattern electrically connect the fifth light-emitting element 45 and the sixth light-emitting element 46 in parallel, respectively.

The light source device 100 in this embodiment is used, for example, as a light source for a rear combination lamp that combines a brake lamp and a tail lamp mounted on a vehicle. When used in this manner, for example, the first light-emitting element 41 to the fourth light-emitting element 44 connected in series are used as a brake lamp driven by a relatively large driving power, and the fifth light-emitting element 45 and the sixth light-emitting element 46 connected in parallel are used as a tail lamp driven by a relatively small driving power.

The fifth light-emitting element 45 and the sixth light-emitting element 46 as tail lights are driven in parallel, so even if the wiring of one of the light-emitting elements is broken, the other light-emitting element is guaranteed to light up. Furthermore, the power that should be supplied to the broken side is supplied to the other light-emitting element, so the lighting luminous flux is also guaranteed. Therefore, the fifth light-emitting element 45 and the sixth light-emitting element 46 as tail lights are light-emitting elements whose brightness is not impaired even if the wiring of one of them is broken.

The first light-emitting element 41 to the sixth light-emitting element 46 generate more heat when driven than the driving element 13. Therefore, by arranging the first light-emitting element 41 to the sixth light-emitting element 46 on the upper surface of the second substrate portion 15 (aluminum nitride substrate) which has a higher thermal conductivity than the first substrate portion 14 (glass epoxy substrate), the heat generated when the first light-emitting element 41 to the sixth light-emitting element 46 are driven can be efficiently dissipated via the second substrate portion 15 and the heat sink 130.

In addition, by placing the driving element 13 on the top surface of the first substrate portion 14 (glass epoxy substrate), which allows a high degree of freedom in wiring and is separated from the second substrate portion 15 by the adhesive layer 35, the heat generated when the first light-emitting element 41 to the sixth light-emitting element 46 are driven is less likely to directly affect the driving element 13. Therefore, it is possible to prevent the driving element 13 from overheating due to the heat.

When using a substrate 11 consisting of a first substrate portion 14 (glass epoxy substrate) and a second substrate portion 15 (aluminum nitride substrate), the thermal expansion coefficients of the two are different; specifically, the thermal expansion coefficient of the glass epoxy substrate is 14-15 ppm/°C, and the thermal expansion coefficient of the aluminum nitride substrate is 4.6 ppm/°C. Therefore, temperature changes during the manufacture of the light source device or in the usage environment may cause breaks in the wiring formed on the top surface of the substrate 11.

For example, when the resin filled in the frame 51 is thermally cured to form the above-mentioned sealing portion 52, the resin shrinks, generating a shrinkage stress that causes the upper surface of the second substrate portion 15, i.e., the aluminum nitride substrate, to shrink inward. This shrinkage stress can cause a misalignment between the first substrate portion 14 and the second substrate portion 15, or cause the second substrate portion 15 to deform away from the first substrate portion 14. This can cause a break in the wiring that straddles the first substrate portion 14 and the second substrate portion 15.

According to this embodiment, as described above, in a plan view, the first wiring 61 to the fourth wiring 64 are arranged across the first substrate portion 14 and the second substrate portion 15 while covering the corners C1 to C4 of the second substrate portion 15 and their respective peripheral areas. In other words, the first wiring 61 to the fourth wiring 64 each hold down the corners C1 to C4 of the second substrate portion 15 and their peripheral areas where deformation may be large.

In addition, since the first wiring 61 to the fourth wiring 64 each suppress the corners C1 to C4, deformation near the midpoints of the sides 15YA, 15YB, 15ZA, and 15ZB can be suppressed very slightly, making it possible to arrange thin wires across the midpoints of the sides. Therefore, the planar shape of the second substrate portion 15 is preferably rectangular rather than circular, and preferably has a rectangular shape that circumscribes the frame body 51.

Therefore, according to this embodiment, even if the second substrate portion 15 is subjected to shrinkage stress during resin hardening as described above, it is possible to prevent the second substrate portion 15 from deforming and causing a misalignment between the first substrate portion 14 and the second substrate portion 15, or the second substrate portion 15 from separating from the first substrate portion 14.

This also makes it possible to suppress deformation of the portion along the center line CL1 of the second substrate portion 15, so that even if a narrow wiring such as the seventh wiring 67 or the eighth wiring 68 is arranged across the first substrate portion 14 and the second substrate portion 15, breaks in the wiring can be suppressed.

Therefore, according to this embodiment, it is possible to prevent the wiring from being broken during the manufacture of the light source device 100, while suppressing the influence of heat generated during the operation of the light-emitting elements in the light-emitting module 110 on the driving elements.

[Method of manufacturing the light source device 100]
1 to 4, a method for producing the light source device 100 in this embodiment will be described. Note that, again, the direction perpendicular to the substrate 11 will be referred to as the up-down direction.

Before describing the light source device 100, a method for manufacturing the substrate 11 used in the embodiment will be described. First, a composite substrate is prepared in which the second substrate portion 15 is embedded and bonded via an adhesive layer 35 into the through-hole 14H of the first substrate portion 14 (multilayer substrate) with jumper wiring inside. Next, a Cu layer is formed on both surfaces of the composite substrate by electroless plating and electrolytic plating. The Cu layer can also be formed by hot pressing copper foil onto the substrate. After that, wiring including the first wiring 61 to the eighth wiring 68 is patterned on the upper surface, and a thermal diffusion film 37 is patterned on the lower surface (rear surface) to obtain the substrate 11.

First, a substrate 11 consisting of a first substrate portion 14 and a second substrate portion 15 is prepared, and a light-emitting device 12 is mounted on the upper surface of the second substrate portion 15 (step 1, light-emitting device mounting process).

Specifically, a solder paste solder consisting of AuSn particles is applied to the upper surface of the second substrate portion 15 of the substrate 11 on which various wiring is formed, and each of the first light-emitting element 41 to the sixth light-emitting element 46 is placed and heated. This causes the AuSn particles contained in the solder paste solder to melt and solidify, thereby bonding each of the first light-emitting element 41 to the sixth light-emitting element 46 to the upper surface of the second substrate portion 15.

After that, as shown in FIG. 3, bonding wires W are bonded to each of the first light-emitting element 41 to the sixth light-emitting element 46 and the wiring connected thereto, and a resin that will become the frame body 51 is applied so as to surround each of the first light-emitting element 41 to the sixth light-emitting element 46. Then, a transparent resin that will become the sealing portion 52 is injected into the frame body 51 so as to seal the first light-emitting element 41 to the sixth light-emitting element 46, the wiring connected thereto, and the bonding wires W, and the resin is thermally cured. This results in a light-emitting device 12 provided on the upper surface of the second substrate portion 15.

Next, the driving element 13 is mounted on the top surface of the first substrate portion 14 (step 2, driving element mounting process).

Specifically, a metal mask is applied to match the wiring pattern formed on the top surface of the first substrate portion 14, and after solder printing, each of the driving elements 13 is placed and reflow is performed. This allows the driving elements 13 to be mounted on the top surface of the first substrate portion 14. Through steps 1 and 2 described above, the light emitting module 110 in the light source device 100 of this embodiment is produced.

Finally, the light emitting module 110 produced in steps 1 and 2 above is combined with the housing holder 120, the heat sink 130, and the power supply connector 140 to produce the light source device 100 (step 3, light source device assembly process).

First, the heat receiving portion 25 of the heat sink 130 is inserted into the through hole 19H1 of the housing holder 120 to integrate the housing holder 120 and the heat sink 130. The power supply connector 140 is then inserted into the through hole 19H2 of the housing holder 120 and fixed in place.

Then, a sealant 28 is applied to the interface between the upper surface 19S of the module housing section 19 and the upper surface 25S of the heat receiving section 25, and a thermally conductive adhesive 29 is applied to the upper surface 25S of the heat receiving section 25. The light emitting module 110 is then attached and thermally cured (120°C for 1 h).

Then, the lead terminal 32 of the power supply connector 140 is inserted into a terminal hole (not shown) in the first board portion 14 of the board 11 and soldered to that portion, thereby electrically connecting the board 11 and the lead terminal 32. This makes it possible to supply power to the light emitting device 12 and the driving element 13. Finally, the O-ring 22 is attached in a state aligned with the outer circumferential surface of the cylindrical wall portion 18 of the housing holder 120. By carrying out the above steps 1 to 3, the light source device 100 of this embodiment can be produced.

In addition, in addition to the LEDs described above, light-emitting elements such as laser diodes (LDs) can be used for the light-emitting device 12 of the light source device 100 in this embodiment. Furthermore, the light emitted from each of the first light-emitting element 41 to the sixth light-emitting element 46 of the light-emitting device 12 is not limited to red light, but can be orange light or white light depending on the type of vehicle lamp used. For example, orange light is used when used as a direction indicator (turning lamp), and white light is used when used as a headlight (low beam, high beam) or a vehicle width lamp (position lamp).

In addition, in this embodiment, the substrate 11 has been described as being integrated with the second substrate portion 15 by being disposed within the through hole 14H of the first substrate portion 14, but the configuration is not limited to this. For example, the substrate 11 may be configured such that the second substrate portion 15 is disposed inside a recess formed by recessing a portion of the first substrate portion 14. Furthermore, the substrate 11 is not limited to being configured such that the first substrate portion 14 and the second substrate portion 15 are integrated via the adhesive layer 35 described above, but may also be configured such that they are directly fitted inside the through hole 14H or the recess.

[Example of use of light source device 100]
An example of use of the light source device 100 will be described below with reference to Fig. 5. Fig. 5 is a side view of a vehicle lamp 200 using the light source device 100. Note that in Fig. 5, for ease of explanation, only a cross section of a lamp housing 210 is shown.

The vehicle lamp 200 is composed of the above-mentioned light source device 100 and a lamp housing 210 attached to a storage holder 120 so as to cover the light-emitting module 110 of the light source device 100.

The lamp housing 210 has a cylindrical light source socket 71 that covers the cylindrical wall portion 18 of the storage holder 120, a hollow truncated cone-shaped reflector 72 that extends from the light source socket 71 toward the left in the figure and has an inner surface that is reflective to the red light emitted from the light source device 100, and a transparent outer lens 73 that is arranged to cover the opening of the reflector 72.

The lamp housing 210 is removably attached via an O-ring 22 by the light source socket 71 engaging and fixing with four claws 18C provided on the cylindrical wall portion 18 of the housing holder 120.

The vehicle lamp 200 configured in this manner is provided at each of the rear corners of the vehicle as a rear combination lamp that combines, for example, the brake lights (first light-emitting element 41 to fourth light-emitting element 44) and tail lights (fifth light-emitting element 45 to sixth light-emitting element 46) as described above.

In this embodiment, the light source device 100 is described as being used as a light source for a rear combination lamp, but the method of use is not limited to this. For example, the light source device 100 can be widely applied to vehicle lighting fixtures such as vehicle headlamps, vehicle width lamps (position lamps), auxiliary headlamps (sub-headlamps), front (rear) fog lamps, daytime running lights (DRL) lamps, lid lamps, tail lamps, brake lamps (stop lamps), back lamps, and turn signal lamps (blinker lamps).

REFERENCE SIGNS LIST 11 Substrate 12 Light emitting device 13 Driving element 14 First substrate portion 15 Second substrate portion 17, 24 Base portion 18 Cylindrical wall portion 19 Module accommodating portion 21 Socket portion 22 O-ring 24 Heat receiving portion 26 Heat dissipation fin 28 Sealing material 29 Thermally conductive adhesive 31 Main body portion 32 Lead terminal 100 Light source device 110 Light emitting module 120 Accommodating holder 130 Heat sink 140 Power supply connector 200 Vehicle lamp 210 Lamp housing

Claims (9)

a light-emitting module including a substrate including a first substrate portion having a through hole with a rectangular planar shape and a second substrate portion provided within the through hole so as to close the through hole and integrated with the first substrate portion, the second substrate portion having a higher thermal conductivity than the first substrate portion, a plurality of light-emitting elements disposed on a surface of the second substrate portion on one main surface of the substrate, and a sealing portion formed on the second substrate portion on one main surface of the substrate and made of a resin for sealing the plurality of light-emitting elements;
a heat sink joined to the second substrate portion on the other main surface of the substrate of the light emitting module;
The light source device is formed with a first wiring pattern on the substrate, the first wiring pattern including two wires each arranged to straddle the first substrate portion and the second substrate portion at each of two corners that sandwich one side of the through hole on one main surface of the substrate, and supplying power to at least one of the plurality of light-emitting elements, and a second wiring pattern including a wire arranged to straddle the first substrate portion and the second substrate portion in a portion between the two corners of the one side, and supplying power to at least one of the plurality of light-emitting elements. The light source device according to claim 1, characterized in that the plurality of light-emitting elements include a first light-emitting element and a second light-emitting element having a smaller driving power than the first light-emitting element, and the second wiring pattern supplies power to the second light-emitting element. The light source device according to claim 2, characterized in that the second wiring pattern extends along the perpendicular bisector of the first side in a portion that straddles the first substrate portion and the second substrate portion. The light source device according to claim 1 or 2, characterized in that the first wiring pattern further includes two wirings provided so as to straddle the first substrate portion and the second substrate portion at each of two corners that sandwich the other side opposite the one side of the through hole. The light source device according to claim 1 or 2, characterized in that the other main surface of the substrate has a metal film formed to cover the entire surface of the second substrate portion and reach the surface of the first substrate portion, and the outer edge of the metal film is aligned with the outer edge of the through hole. The light source device according to claim 1 or 2, characterized in that a driving element used to drive the plurality of light-emitting elements is mounted on the surface of the first substrate portion. The light source device according to claim 6, characterized in that the first substrate portion and the second substrate portion are separated by a resin material. The light source device according to claim 1 or 2, characterized in that the second substrate portion is made of aluminum nitride. The light source device according to claim 1 or 2,
a lamp housing connected to the light source device so as to cover the light emitting module and including a lens for transmitting light emitted from the light source device;
A vehicle lamp comprising:

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