Light source device and light emission emblem

Abstract

To provide a light source device capable of excellent heat dissipation of a light emission element as a light source and capable of suppressing a heat load even when a plurality of light emission elements are close to each other, and to provide a light emission emblem including the light source device.SOLUTION: The present invention provides a light source device 1 comprising: light emission devices 10a and 10b in which a light emission element 14 as a light source is mounted to an element substrate 11; and a circuit board 20 to which the light emission devices 10a and 10b are mounted. In each of the light emission devices 10a and 10b, the element substrate 11 comprises: an electrode pad 12 connected to the light emission element 14; and a heat transfer pad 13 insulated from the light emission element 14. The circuit board 20 includes a circuit pad 22 connected to the electrode pad 12 of the light emission devices 10a and 10b, and a heat dissipation pad 23 insulated from the electrode pad 12 of the light emission devices 10a and 10b, and the heat transfer pads 13 of the light emission devices 10a and 10b are commonly connected to the heat dissipation pad 23 of the circuit board 20.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a light source device and a light-emitting emblem. [Background technology]

[0002] Conventionally, a technique has been known in which a plurality of light-emitting elements are mounted close to each other to bring the plurality of light-emitting elements closer to a point light source (see Patent Document 1). Patent Document 1 discloses a method of mounting a plurality of light-emitting elements close to each other, utilizing the self-alignment effect that occurs when a bonding member is heated and melted. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-153134 Summary of the Invention [Problem to be solved by the invention]

[0004] However, when a plurality of light emitting elements, which are heat sources, are located close to each other, the heat load on the light emitting elements increases due to the heat from the adjacent light emitting elements, accelerating the deterioration of the light emitting elements.

[0005] The object of the present invention is to provide a light source device that has excellent heat dissipation properties for the light-emitting element that serves as the light source, and that can reduce thermal load even when multiple light-emitting elements are located close to each other, and an illuminating emblem equipped with such a light source device. [Means for solving the problem]

[0006] In order to achieve the above object, one aspect of the present invention provides the following light source device.

[0007] [1] A light source device comprising: a plurality of light emitting devices, each having a light emitting element mounted on an element substrate as a light source; and a circuit board on which the plurality of light emitting devices are mounted; in each of the plurality of light emitting devices, the element substrate comprises an electrode pad connected to the light emitting element and a heat transfer pad insulated from the light emitting element; the circuit board comprises circuit pads connected to the electrode pads of the plurality of light emitting devices and heat dissipation pads insulated from the electrode pads of the plurality of light emitting devices; and the heat transfer pads of the plurality of light emitting devices are commonly connected to the heat dissipation pad of the circuit board. [2] The light source device according to [1] above, wherein the plurality of light emitting devices are arranged so that the distance between the heat transfer pads is closer than the distance between the electrode pads. [3] The light source device described in [1] or [2] above, wherein the heat dissipation pad includes a first pad provided on the mounting surface of the circuit board for the plurality of light-emitting devices and a second pad provided on the surface behind the mounting surface. [4] The light source device according to [3] above, wherein the first pad and the second pad are connected through a via that penetrates the circuit board. [5] The light source device according to [1] or [2] above, wherein among the plurality of light emitting devices, some light emitting devices have a different lighting timing from the other light emitting devices. [6] The light source device according to [5] above, wherein the some light emitting devices and the other light emitting devices have different emission wavelengths. [7] The light source device described in [1] above, wherein the heat dissipation pad has a band-like planar shape, and the plurality of light emitting devices include a plurality of first light emitting devices lined up along the length of the planar shape on one side of the width of the planar shape of the heat dissipation pad, and a plurality of second light emitting devices lined up along the length of the planar shape on the other side of the width of the planar shape of the heat dissipation pad, and each of the plurality of first light emitting devices and the plurality of second light emitting devices are electrically connected in series via a plurality of the circuit pads lined up along the length of the planar shape. [8] The light source device according to [7] above, wherein the plurality of first light emitting devices and the plurality of second light emitting devices have different amounts of heat generation. [9] A light-emitting emblem comprising the light source device described in [7] above and an ornament having a light-transmitting region for transmitting light emitted from the light source device from the back side to the front side, wherein in the light source device, the plurality of light-emitting devices are arranged side by side along the edge of the circuit board so that the plurality of first light-emitting devices are located on the inside and the plurality of second light-emitting devices are located on the outside.

[10] The light-emitting emblem according to [9] above, wherein the heat generation amount of the plurality of first light-emitting devices is higher than the heat generation amount of the plurality of second light-emitting devices.

[11] A luminous emblem as described in [9] or

[10] above, wherein the CIE standard spectral luminous efficiency for photopic vision at the emission peak wavelength of the first light-emitting device is higher than the CIE standard spectral luminous efficiency for photopic vision at the emission peak wavelength of the second light-emitting device, and the CIE standard spectral luminous efficiency for scotopic vision at the emission peak wavelength of the second light-emitting device is higher than the CIE standard spectral luminous efficiency for scotopic vision at the emission peak wavelength of the first light-emitting device.

[12] A light source device comprising: a plurality of light emitting devices, each having a light emitting element mounted on an element substrate as a light source; and a circuit board on which the plurality of light emitting devices are mounted; in each of the plurality of light emitting devices, the element substrate has an anode electrode pad and a cathode electrode pad connected to the light emitting element; each of the plurality of light emitting devices is arranged so that a first electrode pad, which is one of the anode electrode pad and the cathode electrode pad, is closer to a light emitting center position of the plurality of light emitting devices than a second electrode pad, which is the other of the anode electrode pad and the cathode electrode pad; and the first electrode pads of the plurality of light emitting devices are commonly connected to a single first circuit pad provided on the circuit board.

[13] The light source device according to

[12] above, wherein the plurality of light emitting devices are three or more of the light emitting devices.

[14] The light source device according to

[12] or

[13] above, wherein the distance between any two of the plurality of light emitting devices is 0.5 mm or less.

[15] A light source device as described in

[12] or

[13] above, wherein in each of the plurality of light-emitting devices, the element substrate has a heat transfer pad insulated from the light-emitting element, and the heat transfer pads of the plurality of light-emitting devices are commonly connected to the first circuit pad. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a light source device that has excellent heat dissipation properties for the light-emitting element that is the light source, and that can reduce thermal load even when multiple light-emitting elements are located close to each other, and an illuminating emblem that is equipped with this light source device. [Brief explanation of the drawings]

[0009] [Figure 1] Fig. 1(a) is a vertical cross-sectional view of a light source device according to a first embodiment of the present invention, and Fig. 1(b) is a schematic diagram showing the positional relationship in a planar direction of an electrode pad, a heat transfer pad, a light emitting element, and a heat dissipation pad of a circuit board of a light emitting device. [Figure 2] 2(a) to 2(c) are vertical cross-sectional views showing modified examples of the light source device according to the first embodiment of the present invention. [Figure 3] 3(a) and 3(b) are vertical cross-sectional views showing modified examples of the light source device according to the first embodiment of the present invention. [Figure 4] 4(a) to 4(c) are schematic diagrams showing examples of arrangement patterns of a plurality of light emitting devices. [Figure 5] 5(a) to 5(c) are schematic diagrams showing other examples of arrangement patterns of a plurality of light emitting devices. [Figure 6] FIG. 6 is a schematic diagram showing a specific example of an arrangement in which a plurality of light emitting devices are arranged in a line. [Figure 7] FIG. 7 is a vertical cross-sectional view of a light-emitting emblem that uses a light source device in which a plurality of light-emitting devices are arranged in a line. [Figure 8] FIG. 8(a) is a plan view of a circuit board used in the light-emitting emblem, and FIG. 8(b) is an enlarged view of the part surrounded by a circle R shown in FIG. 8(a). [Figure 9] Fig. 9(a) is a vertical cross-sectional view of a light source device according to a second embodiment of the present invention, and Fig. 9(b) is a schematic diagram showing the positional relationship in a planar direction between electrode pads and light-emitting elements of a light-emitting device, and circuit pads of a circuit board. [Figure 10]Fig. 10(a) is a schematic diagram showing an example of an arrangement pattern of three light emitting devices according to the second embodiment of the present invention, and Fig. 10(b) is a schematic diagram showing an example of an arrangement pattern of four light emitting devices according to the second embodiment of the present invention. [Figure 11] 11(a) to 11(c) are schematic diagrams showing examples of other arrangement patterns of the light emitting device according to the second embodiment of the present invention. [Figure 12] Fig. 12(a) is a vertical cross-sectional view of a modified example of the light source device according to the second embodiment of the present invention, and Fig. 12(b) is a schematic diagram showing the positional relationship in the planar direction of the electrode pads, heat transfer pads, and light emitting elements of the light emitting device, and the circuit pads of the circuit board. [Figure 13] Fig. 13(a) is a schematic diagram showing an example of an arrangement pattern of three light emitting devices according to a modified example of the second embodiment of the present invention, and Fig. 13(b) is a schematic diagram showing an example of an arrangement pattern of four light emitting devices according to a modified example of the second embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0010] [First embodiment] 1(a) is a vertical cross-sectional view of a light source device 1 according to a first embodiment of the present invention. The light source device 1 includes a plurality of light emitting devices 10 (10a, 10b) each having a light emitting element 14 as a light source mounted on an element substrate 11, and a circuit board 20 on which the plurality of light emitting devices 10 are mounted.

[0011] The light emitting device 10 is a surface-mounted light emitting device (SMD). In each of the light emitting devices 10, the element substrate 11 includes an electrode pad 12 connected to the light emitting element 14 and a heat transfer pad 13 insulated from the light emitting element 14.

[0012] The circuit board 20 includes circuit pads 22 connected to the electrode pads 12 of the plurality of light emitting devices 10, and heat dissipation pads 23 insulated from the electrode pads 12 of the plurality of light emitting devices 10.

[0013] The heat transfer pads 13 of the plurality of light emitting devices 10 are commonly connected to a heat dissipation pad 23 of the circuit board 20 .

[0014] The element substrate 11 of the light emitting device 10 is a circuit board having a circuit to which the light emitting element 14 is connected. The light emitting element 14 is typically an LED (light-emitting diode) chip, but other light emitting elements such as an LD (laser diode) chip may also be used as the light emitting element 14. The element substrate 11 is an insulating substrate whose base material is an insulating material such as alumina or AlN.

[0015] The electrode pads 12 and the heat transfer pads 13 are made of a metal such as Au, etc. The electrode pads 12 and the heat transfer pads 13 can be formed, for example, using the same material in the same process.

[0016] The plate-shaped base material 21 of the circuit board 20 is made of an insulating material such as glass epoxy.

[0017] The circuit pads 22 and the heat dissipation pads 23 are made of a metal such as Cu, etc. The circuit pads 22 and the heat dissipation pads 23 can be formed, for example, using the same material and in the same process.

[0018] 1(a), light emitting devices 10a and 10b are exemplified as the plurality of light emitting devices 10, and the heat transfer pads 13 of the light emitting devices 10a and 10b are commonly connected to one heat dissipation pad 23. In the light source device 1, the number of the plurality of light emitting devices 10 whose heat transfer pads 13 are commonly connected to one heat dissipation pad 23 is not particularly limited.

[0019] The electrode pads 12 of the light emitting device 10 and the circuit pads 22 of the circuit board 20 are connected via a bonding material 31 made of solder such as SnAgCu. The heat transfer pads 13 of the light emitting device 10 and the heat dissipation pads 23 of the circuit board 20 are connected via a bonding material 32 made of solder such as SnAgCu. The surface of the circuit board 20 is covered with an insulating resist 33, for example.

[0020] The electrode pads 12 of the light emitting device 10, the bonding material 31, and the circuit pads 22 of the circuit board 20 are electrically connected to the light emitting elements 14, and are conductive when the light emitting device 10 is in operation.

[0021] On the other hand, the heat transfer pad 13 of the light emitting device 10, the bonding material 32, and the heat dissipation pad 23 of the circuit board 20 are components for dissipating heat from the light emitting element 14, and are not electrically connected to the light emitting element 14 and are not conductive when the light emitting device 10 is operating.

[0022] Heat generated by the operation of the light emitting element 14 is transmitted from the light emitting element 14 to the heat transfer pad 13, the bonding material 32, and the heat dissipation pad 23 in this order, and is dissipated to the circuit board 20 side.

[0023] FIG. 1(b) is a schematic diagram showing the positional relationship in the planar direction of the electrode pads 12, heat transfer pads 13, and light emitting elements 14 of the light emitting devices 10a and 10b, and the heat dissipation pads 23 of the circuit board 20. As shown in FIG.

[0024] In order to dissipate heat from the light emitting element 14, the heat transfer pad 13 and the bonding material 32, and the bonding material 32 and the heat dissipation pad 23 overlap in a plane. In order to dissipate heat from the light emitting element 14 more efficiently, it is preferable that the entire surface of the heat transfer pad 13 facing the bonding material 32 is covered with the bonding material 32, and the entire surface of the bonding material 32 facing the heat dissipation pad 23 is covered with the heat dissipation pad 23. The area of ​​the heat dissipation pad 23 can be made large as long as it does not come into contact with pads or wiring, such as the circuit pad 22, on the circuit board 20 that are electrically connected to the light emitting element 14.

[0025] The plurality of light emitting devices 10 are preferably arranged so that the distance between their heat transfer pads 13 is closer than the distance between their electrode pads 12. In other words, the heat transfer pads 13 of the plurality of light emitting devices 10 are preferably located toward the center of the arrangement of the plurality of light emitting devices 10 (toward the light emitting center position C of the plurality of light emitting devices 50). Here, the light emitting center of the plurality of light emitting devices 50 is the center of the entire light emitting region of the plurality of light emitting devices 50, and the light emitting center position C is at the center of the light emitting elements 14 of the plurality of light emitting devices 50.

[0026] For example, in the example shown in Figures 1(a) and (b), both heat transfer pads 13 are located on the central side of the arrangement of the light emitting devices 10a and 10b (on the side of the light emitting center position C of the light emitting devices 10a and 10b), and the electrode pad 12 is located on the side away from the center.

[0027] In this case, by disposing one heat dissipation pad 23 between a plurality of light emitting devices 10, the heat transfer pads 13 of the plurality of light emitting devices 10 can be commonly connected to the pad.

[0028] Furthermore, in this case, even when multiple light-emitting devices 10 are arranged so that the light-emitting elements 14 are close to each other in order to reduce the light-emitting area, as shown in Figures 1(a) and (b), heat can be efficiently dissipated through the heat transfer pad 13 arranged near the center of the arrangement of the multiple light-emitting devices 10, thereby suppressing deterioration of the light-emitting elements 14 due to thermal load.

[0029] In the example shown in Figures 1(a) and (b), the light-emitting devices 10a and 10b are arranged so that the light-emitting elements 14 face each other closely, and the light-emitting area is a relatively narrow region centered on the light-emitting center position C located halfway between the two light-emitting elements 14.

[0030] The smaller light-emitting area reduces uneven brightness and color of the light source device 1. Furthermore, the smaller light-emitting area improves the light-collection efficiency on the light control components when the light source device 1 is used in combination with light-guiding components, light-receiving components, and other light control components.

[0031] In order to reduce the light-emitting area of ​​the light source device 2 by bringing the light-emitting elements 14 of the plurality of light-emitting devices 10 closer to each other, the interval between the plurality of light-emitting devices 10 (the interval between any two light-emitting devices 10 among the plurality of light-emitting devices 10) is preferably 0.5 mm or less, more preferably 0.3 mm or less, and even more preferably 0.1 mm or less. The light-emitting devices 10 may also be in contact with each other.

[0032] The heat dissipation pads provided on the circuit board 20 preferably include heat dissipation pads 24 provided on the surface behind the mounting surface, in addition to heat dissipation pads 23 provided on the mounting surface of the circuit board 20 on which the plurality of light emitting devices 10 are mounted. By using heat dissipation pads 24, the heat dissipation effect from the back surface of the circuit board 20 can be improved.

[0033] When using the heat dissipation pad 24, connecting the heat dissipation pad 23 and the heat dissipation pad 24 through vias 25 that penetrate the circuit board 20 allows efficient heat transfer to the heat dissipation pad 24, thereby further improving the heat dissipation effect from the back surface of the circuit board 20. The area of ​​the heat dissipation pad 24 can be increased as long as it does not come into contact with pads or wiring, such as the circuit pads 22, on the circuit board 20 that are electrically connected to the light emitting element 14. The number of vias 25 can also be increased depending on the area of ​​the heat dissipation pad 23.

[0034] The via 25 may be a film that covers the inner surface of a via hole that penetrates the circuit board 20, but is preferably a film that fills the via hole in order to further improve thermal conductivity. The via 25 is made of a metal such as Cu.

[0035] The light source device 1 can be used in combination with a rod-shaped light guide, for example, as a light source device used in an instrument panel inside a vehicle. In this case, the light source device 1 is placed at one or both ends of the rod-shaped light guide, and emits light toward the inside of the light guide.

[0036] As described above, the light source device 1 has a plurality of light emitting devices 10 arranged so that the light emitting elements 14 are close to each other, and can emit light with a small light emitting area and high light emission intensity.

[0037] Therefore, sufficient brightness can be obtained even when the light source device 1 is disposed at only one end of a rod-shaped light guide. Furthermore, in ceiling lighting or the like extending in the longitudinal direction of a vehicle, even when the light guide has a length of 50 cm or more, or even 1 meter or more, sufficient brightness can be obtained by using the light source device 1.

[0038] 2(a) to 2(c) and 3(a) and 3(b) are vertical cross-sectional views showing modified examples of the light source device 1. FIG.

[0039] 2(a), the circuit board 20 may include a non-conductive pad 21b therein. In this case, the circuit board 20 is composed of a base material 21a made of an insulating material and the non-conductive pad 21b. The non-conductive pad 21b is not electrically connected to the light-emitting element 14 and is not conductive when the light-emitting device 10 is in operation.

[0040] The non-conductive pad 21b is made of a metal such as Cu and has a higher thermal conductivity than the base material 21a. Therefore, by using the non-conductive pad 21b, heat generated in the light emitting element 14 and the light emitting device 10 can be effectively dissipated. The non-conductive pad 21b is preferably in contact with the vias 25 to facilitate heat transfer from the vias 25. The area of ​​the non-conductive pad 21b can be increased as long as it does not come into contact with wiring and vias inside or on the side of the circuit board 20 that are electrically connected to the light emitting element 14. The number of vias 25 can also be increased depending on the area of ​​the heat dissipation pad 23.

[0041] 2(b), the circuit board 20 may be a single-sided board having a wiring pattern provided on only one side. Even in this case, heat generated by the light-emitting element 14 and the light-emitting device 10 can be effectively dissipated.

[0042] Furthermore, as shown in FIG. 2(c), when an insulating layer 34 is provided on the surface of the circuit board 20, which is a single-sided board, and the base material 21 is insulated from the light-emitting element 14, a conductive material, for example, a metal such as Al having high thermal conductivity, can be used as the material for the base material 21.

[0043] 3(a), in the light emitting device 10, the light emitting element 14 may be sealed with a sealing material 15. The sealing material 15 is made of a resin such as silicone.

[0044] 3(b), a wavelength conversion member 16 containing a phosphor may be disposed on the light emitting element 14 and sealed with a sealing material 15. For example, by setting the emission color of the light emitting element 14 to blue and the fluorescent color of the wavelength conversion member 16 to yellow, white light can be extracted from the light source device 1.

[0045] Wavelength conversion member 16 is, for example, a transparent resin such as silicone with phosphor particles dispersed in it. In this case, it is preferable that sealing material 15 is made of a light-reflecting material such as white silicone resin, and that the upper surface of wavelength conversion member 16 is exposed and not covered by sealing material 15.

[0046] 4(a) to 4(c) are schematic diagrams showing examples of arrangement patterns of a plurality of light emitting devices 10. Figures 4(a) to 4(c) mainly show the positional relationship in the planar direction of the heat transfer pads 13 and light emitting elements 14 of the light emitting devices 10a, 10b, and 10c, and the heat dissipation pad 23 of the circuit board 20.

[0047] 4(a) to 4(c) all show an example in which the heat transfer pads 13 of three light emitting devices 10 (10a, 10b, 10c) are connected to one common heat dissipation pad .

[0048] In the example shown in Figures 4(a) to (c), light emitting devices 10a, 10b, and 10c are arranged so that each light emitting element 14 faces closely, and the light emitting area is a relatively narrow area centered on light emitting center position C located halfway between the three light emitting elements 14.

[0049] 5(a) to 5(c) are schematic diagrams showing other examples of arrangement patterns of a plurality of light emitting devices 10. Figures 5(a) to 5(c) mainly show the positional relationship in the planar direction between the light emitting elements 14 of the light emitting devices 10a and 10b and the heat dissipation pads 23 of the circuit board 20.

[0050] 5(a) to 5(c), the light emitting devices 10a and 10b are turned on at different timings. That is, during operation of the light source device 1, there is a period when one of the light emitting devices 10a and 10b is turned on while the other is turned off. Note that even in the examples shown in FIGS. 1 to 4, there may be a period when one of the light emitting devices 10a and 10b is turned on while the other is turned off.

[0051] The timing of lighting of the light emitting devices 10a and 10b is controlled by, for example, a control unit mounted on the vehicle and mainly composed of a microcomputer.

[0052] The heat transfer pads 13 of the light emitting devices 10a and 10b are commonly connected to one heat dissipation pad 23. In the example shown in FIG. 5(a), the heat transfer pads 13 of one light emitting device 10a and one light emitting device 10b are commonly connected to one heat dissipation pad 23. In the example shown in FIG. 5(b), the heat transfer pads 13 of two light emitting devices 10a and two light emitting devices 10b are commonly connected to one heat dissipation pad 23. In the example shown in FIG. 5(c), the heat transfer pads 13 of four light emitting devices 10a and four light emitting devices 10b are commonly connected to one heat dissipation pad 23.

[0053] In this case, the light-emitting device 10a or the light-emitting device 10b that is turned off does not emit heat, and therefore, only the light-emitting device that is turned on can use the heat dissipation pad 23. Therefore, compared to when the light-emitting device 10a and the light-emitting device 10b are connected to separate heat dissipation pads 23, the area of ​​the heat dissipation pad 23 that can be used for heat dissipation is larger, allowing for more efficient heat dissipation.

[0054] That is, when some of the light emitting devices 10 have different lighting timings than the other light emitting devices 10, heat can be efficiently dissipated by commonly connecting the heat transfer pads 13 of those light emitting devices 10 to a single heat dissipation pad 23. This allows, for example, a larger amount of power to be supplied to the light emitting devices 10, thereby improving the brightness of the light source device 1.

[0055] For example, some of the light emitting devices 10 that have different lighting timings have different emission wavelengths from the other light emitting devices 10, and lighting is switched based on the visibility of the emitted light colors.

[0056] In this case, in the example shown in Figures 5(a) to (c), the emission wavelengths of the light-emitting element 14a of the light-emitting device 10a and the light-emitting element 14b of the light-emitting device 10b are different, and lighting is switched based on the visibility of the emission colors of the light-emitting devices 10a and 10b.

[0057] Specifically, when the environment in which the light source device 1 is used is bright (for example, greater than 1000 lx), the light emitting device 10a, which emits light with a long dominant wavelength (for example, green light) that has excellent visibility in photopic vision, is turned on, and when the environment in which the light source device 1 is used is dark (for example, 1000 lx or less), the light emitting device 10b, which emits white light or light with a short dominant wavelength (for example, blue light) that has excellent visibility in scotopic vision, is turned on.

[0058] In this case, for example, the brightness of the environment in which the light source device 1 is used is measured by an illuminance sensor, and based on the brightness value measured by the illuminance sensor, the above-mentioned control unit turns on either the light-emitting device 10a or the light-emitting device 10b.

[0059] Furthermore, the control unit may turn on either light emitting device 10a or light emitting device 10b in conjunction with the on / off of an in-vehicle device such as a headlamp.

[0060] As shown in FIGS. 5(a) to 5(c), when light emitting devices 10 with different emission wavelengths are arranged evenly in a plane, uniform surface light emission can be achieved regardless of which one is turned on.

[0061] Furthermore, when the light source device 1 is used as the light source for a light-emitting emblem, light-emitting devices 10 with different emission wavelengths may be arranged in a desired pattern to emit light in a desired shape.

[0062] Furthermore, for example, when the light source device 1 includes light emitting devices 10 each having a different emission wavelength, the light source devices 1 may be disposed at one end or both ends of a rod-shaped light guide.

[0063] Fig. 6 is a schematic diagram showing a specific example of an arrangement in which a plurality of light emitting devices 10 are arranged linearly. Fig. 6 mainly shows the planar positional relationship of the electrode pads 12a, 12b, heat transfer pad 13, and light emitting element 14 of the light emitting device 10 (10x, 10y), as well as the circuit pad 22 and heat dissipation pad 23 of the circuit board 20. Hereinafter, the light source device 1 having a configuration in which a plurality of light emitting devices 10 are arranged linearly, as exemplified in Fig. 6, will be referred to as light source device 1a.

[0064] In the light source device 1a, the heat dissipation pad 23 has a strip-like planar shape. The plurality of light emitting devices 10 includes a plurality of first light emitting devices 10x arranged along the length direction L of the planar shape on one side (upper side in FIG. 6) of the width direction W of the planar shape of the heat dissipation pad 23, and a plurality of second light emitting devices 10y arranged along the length direction L on the other side (lower side in FIG. 6) of the width direction W of the heat dissipation pad 23.

[0065] The heat transfer pads 13 of the plurality of light emitting devices 10 (10x, 10y) are commonly connected to one heat dissipation pad 23. Therefore, as with the other light source devices 1 according to the present embodiment described above, even when the plurality of light emitting devices 10 are arranged so that the light emitting elements 14 are close to each other, heat can be efficiently dissipated via the heat transfer pad 13, and deterioration of the light emitting elements 14 due to thermal load can be suppressed.

[0066] Furthermore, the plurality of first light emitting devices 10x and the plurality of second light emitting devices 10y are electrically connected in series via the plurality of circuit pads 22 arranged along the length direction L of the heat dissipation pad 23.

[0067] That is, one electrode pad 12a and the other electrode pad 12b of the first light-emitting device 10x on both sides are electrically connected by one circuit pad 22. Similarly, one electrode pad 12a and the other electrode pad 12b of the second light-emitting device 10y on both sides are electrically connected by one circuit pad 22.

[0068] In this case, no complex wiring is required to supply current to the electrode pads 12 (12a, 12b) of the plurality of light emitting devices 10, which increases the degree of freedom in the placement positions of the plurality of light emitting devices 10 on the circuit board 20. Furthermore, since the variation in current flowing through the individual light emitting devices 10 is smaller when the plurality of light emitting devices 10 are connected in series than when they are connected in parallel, the variation in brightness is small among the plurality of first light emitting devices 10x and the plurality of second light emitting devices 10y connected in series.

[0069] Here, one of the electrode pads 12a and 12a is the anode-side electrode pad 12, and the other is the cathode-side electrode pad 12. Hereinafter, the anode-side electrode pad 12 will be referred to as the anode electrode pad, and the cathode-side electrode pad 12 will be referred to as the cathode electrode pad. In all of the first light-emitting devices 10x, if the anode electrode pad is electrode pad 12a, the cathode electrode pad will be electrode pad 12b, and if the cathode electrode pad is electrode pad 12a, the anode electrode pad will be electrode pad 12b. Similarly, in all of the second light-emitting devices 10y, if the anode electrode pad is electrode pad 12a, the cathode electrode pad will be electrode pad 12b, and if the cathode electrode pad is electrode pad 12a, the anode electrode pad will be electrode pad 12b.

[0070] It is not necessary for all of the first light-emitting devices 10x and all of the second light-emitting devices 10y included in the light source device 1a to be connected in series; it is sufficient for the light source device 1a to include a plurality of first light-emitting devices 10x connected in series and a plurality of second light-emitting devices 10y connected in series. For example, the light source device 1a may include a plurality of groups in which a plurality of first light-emitting devices 10x are connected in series and these groups are connected in parallel, and similarly, a plurality of groups in which a plurality of second light-emitting devices 10y are connected in series and these groups are connected in parallel. In this case, the circuit input voltage can be reduced compared to when all of the first light-emitting devices 10x and all of the second light-emitting devices 10y included in the light source device 1a are connected in series.

[0071] When the heat generation amounts of the plurality of first light-emitting devices 10x and the plurality of second light-emitting devices 10y are different, the heat load of the light-emitting elements 14 in the entire plurality of light-emitting devices 10 can be reduced by arranging the one with the greater heat generation amount in an area of ​​the circuit board 20 with high heat dissipation properties.

[0072] For example, when the first light emitting device 10x and the second light emitting device 10y differ in at least one of the light emission intensity (light emission intensity of the light emitting element 14) and the light emission wavelength (light emission wavelength of the light emitting element 14), or when the number of the plurality of first light emitting devices 10x differs from the number of the plurality of second light emitting devices 10y, the heat generation amounts of the plurality of first light emitting devices 10x and the plurality of second light emitting devices 10y differ.

[0073] Fig. 7 is a vertical cross-sectional view of a light-emitting emblem 40 that uses a light source device 1a in which a plurality of light-emitting devices 10 are linearly arranged. In Fig. 7, the electrode pads 12, heat transfer pads 13, light-emitting elements 14, circuit pads 22, heat dissipation pads 23, wiring on the circuit board 20, etc. are not shown.

[0074] The luminous emblem 40 is attached to an exterior panel of a vehicle such as an automobile, for example, a grille, a bumper, a garnish, etc. The luminous emblem 40 is typically attached to an exterior panel at the front of the vehicle, such as a front grille, but may also be attached to the rear of the vehicle.

[0075] The light-emitting emblem 40 includes a light source device 1a and a plate-like ornament 41 having a light-transmitting region for transmitting light emitted from the light source device 1a from a back surface 412 side to a front surface 411 side.

[0076] By extracting the light emitted from the light source device 1a to the outside through the light transmitting area of ​​the ornament 41, the design of the emblem provided on the ornament 41 can be illuminated and displayed.

[0077] In the example shown in FIG. 7, the entire ornament 41 is made of a material such as acrylic resin that transmits the light emitted from the light emitting device 10 (10a, 10b), and the entire ornament 41 serves as the light-transmitting region described above.

[0078] The ornament 41 has a groove 410 on the back surface 412, which has a pattern of an emblem design.

[0079] The back surface 412 of the ornament 41 may be subjected to decorative processing for the emblem (for example, coloring, half mirror processing, pattern printing, etc.).

[0080] Fig. 8(a) is a plan view of the circuit board 20 used in the light-emitting emblem 40, and Fig. 8(b) is an enlarged view of the area surrounded by the circle R shown in Fig. 8(a). Note that Fig. 8(a) omits illustration of the light-emitting element 14, circuit pads 22, heat dissipation pads 23, wiring on the circuit board 20, etc.

[0081] In the light source device 1a used in the light-emitting emblem 40, the multiple light-emitting devices 10 are arranged side by side along the edge 201 of the circuit board 20 so that the multiple first light-emitting devices 10x are located on the inside (towards the center of the circuit board 20) and the multiple second light-emitting devices 10y are located on the outside (towards the edge 201 of the circuit board 20).

[0082] The plurality of light emitting devices 10 may be continuously arranged in a ring shape along the edge 201 of the circuit board 20, or may be divided into several groups and arranged intermittently along the edge 201 of the circuit board 20. In addition, in a section where the plurality of light emitting devices 10 are continuously arranged, one heat dissipation pad 23 may be used, or as shown in Fig. 5(c), a plurality of heat dissipation pads 23 separated in the length direction L may be used.

[0083] In the light-emitting emblem 40, the operations (turning on, turning off, etc.) of the multiple light-emitting devices 10 (10x, 10y) are controlled by a light-emitting control unit (not shown). The light-emitting control unit is mainly composed of a microcomputer and is included in, for example, an on-board ECU (Electronic Control Unit).

[0084] In the example shown in FIG. 8( a ), the planar shape of the circuit board 20 is elliptical, and the plurality of light emitting devices 10 are arranged in a ring shape along the edge 201 of the elliptical circuit board 20 .

[0085] As described above, the plurality of first light emitting devices 10x and the plurality of second light emitting devices 10y are electrically connected in series via the plurality of circuit pads 22 arranged along the length of the heat dissipation pad 23. This allows the plurality of light emitting devices 10 to be arranged even in a narrow area near the edge 201 of the circuit board 20.

[0086] As described above, it is not necessary for all of the first light emitting devices 10x and second light emitting devices 10y included in the light source device 1a to be connected in series, and it is sufficient that the light source device 1a includes a plurality of first light emitting devices 10x connected in series and a plurality of second light emitting devices 10y connected in series. For example, the light source device 1a may include a plurality of groups in which a plurality of first light emitting devices 10x are connected in series and these groups are connected in parallel, and similarly, the light source device 1a may include a plurality of groups in which a plurality of second light emitting devices 10y are connected in series and these groups are connected in parallel.

[0087] When multiple light emitting devices 10 are arranged along the edge 201 of the circuit board 20, the area on the inside of the multiple light emitting devices 10 is larger than the outside of the multiple light emitting devices 10, making it easier for heat to escape. Therefore, when the multiple light emitting devices 10 include multiple types of light emitting devices 10 with different heat values, the multiple light emitting devices 10 can be arranged so that the heat value of the multiple first light emitting devices 10x is higher than the heat value of the multiple second light emitting devices 10y, thereby reducing the thermal load on the light emitting elements 14 in the multiple light emitting devices 10 as a whole.

[0088] For example, even when the plurality of light-emitting devices 10 includes two types of light-emitting devices 10 that emit light in different colors and therefore have different heat values, it is preferable to arrange the plurality of light-emitting devices 10 so that the heat value of the plurality of first light-emitting devices 10x arranged on the inside is higher than the heat value of the plurality of second light-emitting devices 10y arranged on the outside. In this case, for example, the plurality of light-emitting devices 10 can be arranged so that the CIE standard spectral luminous efficiency for photopic vision at the emission peak wavelength of the first light-emitting devices 10x is higher than the CIE standard spectral luminous efficiency for photopic vision at the emission peak wavelength of the second light-emitting devices 10y, and the CIE standard spectral luminous efficiency for scotopic vision at the emission peak wavelength of the second light-emitting devices 10y is higher than the CIE standard spectral luminous efficiency for scotopic vision at the emission peak wavelength of the first light-emitting devices 10x.

[0089] The CIE standard spectral luminous efficiencies for photopic and scotopic vision mentioned above represent the degree of brightness for each wavelength perceived by the human eye in bright and dark places, respectively (see JIS Z 8785:2019).

[0090] In the above case, the light emitted by the first light-emitting device 10x is perceived as brighter than the light emitted by the second light-emitting device 10y in a bright place, so the first light-emitting device 10x is made to emit light in a bright place. Conversely, the light emitted by the second light-emitting device 10y is perceived as brighter than the light emitted by the first light-emitting device 10x in a dark place, so the second light-emitting device 10y is made to emit light in a dark place.

[0091] Generally, humans perceive the brightness of light from light-emitting elements such as LEDs less readily in bright places than in dark places. Therefore, the first light-emitting device 10x, which emits light in bright places, is required to have a higher output than the second light-emitting device 10y, which emits light in dark places, which may result in a larger amount of heat generation. Therefore, by arranging the multiple light-emitting devices 10 so that the CIE standard spectral luminous efficiency for photopic vision at the emission peak wavelength of the first light-emitting device 10x is higher than the CIE standard spectral luminous efficiency for photopic vision at the emission peak wavelength of the second light-emitting device 10y, and the CIE standard spectral luminous efficiency for scotopic vision at the emission peak wavelength of the second light-emitting device 10y is higher than the CIE standard spectral luminous efficiency for scotopic vision at the emission peak wavelength of the first light-emitting device 10x, the thermal load of the light-emitting elements 14 in the multiple light-emitting devices 10 as a whole can be reduced.

[0092] In this case, the emitted light colors of the first light-emitting device 10x and the second light-emitting device 10y are, for example, green and white, respectively. That is, green light has a higher CIE standard spectral luminous efficiency for photopic vision at its peak emission wavelength than white light, and white light has a higher CIE standard spectral luminous efficiency for scotopic vision at its peak emission wavelength than green light.

[0093] The light-emitting emblem 40 may include an illuminance sensor that detects the brightness of the surrounding area. In this case, the light-emitting control unit can light up any of the plurality of first light-emitting devices 10x and the plurality of second light-emitting devices 10y based on the brightness value measured by the illuminance sensor.

[0094] Furthermore, the light emission control unit may turn on any of the plurality of first light emitting devices 10x and the plurality of second light emitting devices 10y in conjunction with the turning on and off of vehicle headlamps, for example.

[0095] In addition to the light source device 1a and the ornament 41, the light-emitting emblem 40 includes, for example, a light guide plate 42 that guides light emitted from the multiple light-emitting devices 10 of the light source device 1a to the back surface 412 of the ornament 41, a decorative sheet 43 installed between the light guide plate 42 and the ornament 41, a housing 44 for accommodating the light source device 1a, the light guide plate 42, and the sheet 43, and an annular frame body 45 attached to surround the periphery of the ornament 41.

[0096] The light guide plate 42 takes in light emitted from the plurality of light emitting devices 10 through recesses 421 provided in a portion of the light source device 1a facing the plurality of light emitting devices 10. Then, the light propagating within the light guide plate 42 is reflected by recesses 422 provided on the surface (bottom surface) on the light source device 1a side, and emitted from the surface (top surface) on the ornament 41 side. The light guide plate 42 is made of a material, such as acrylic resin, that transmits light emitted from the light emitting devices 10 (10x, 10y).

[0097] The sheet 43 is a sheet that has been subjected to decorative processing for the emblem (for example, coloring, half-mirror processing, pattern printing, etc.) The sheet 43 is made of a material that transmits light emitted from the light-emitting devices 10 (10x, 10y), such as polycarbonate resin.

[0098] It is preferable that at least one of the decorative processing on the sheet 43 and the decorative processing on the back surface 412 of the ornament 41 is provided with adjusted light transmittance, etc., so that the multiple light-emitting devices 10 are difficult to see from the front surface 411 side of the ornament 41.

[0099] The housing 44 has a bottom plate 441 that is the mounting surface to the vehicle, and side walls 442 that surround the bottom plate 441. The planar shape of the bottom plate 441 corresponds to the planar shape of the circuit board 20, and the light source device 1a is accommodated in an area on the bottom plate 441 that is surrounded by the side walls 442. The ornament 41 is fixed to the upper end of the side walls 442 by welding or adhesive. The housing 44 is made of an opaque synthetic resin such as AES resin.

[0100] As described above, the configuration of the luminous emblem 40 need only be such that the light emitted from the light source device 1a is extracted to the outside through the light-transmitting area of ​​the ornament 41, thereby illuminating and displaying the design of the emblem provided on the ornament 41. The specific configuration is not limited to that shown in Figure 7, and various known luminous emblem configurations can be used.

[0101] (Effects of the first embodiment) In the light source device 1, 1a according to the first embodiment of the present invention, the heat transfer pads 13 of the plurality of light emitting devices 10 are commonly connected to the heat dissipation pad 23 of the circuit board 20, and therefore the heat dissipation of the light emitting elements 14, which are the light source, is excellent, and the thermal load can be reduced even when the plurality of light emitting elements 14 are close to each other.

[0102] Furthermore, in the light source device 1a according to the first embodiment of the present invention, the plurality of first light emitting devices 10x and the plurality of second light emitting devices 10y are connected in series, so that complicated wiring is not required to supply current to the electrode pads 12 (12a, 12b) of the plurality of light emitting devices 10. This allows for a high degree of freedom in the placement positions of the plurality of light emitting devices 10 on the circuit board 20. For example, in a light emitting emblem 40 using the light source device 1a, the plurality of light emitting devices 10 can be placed even in a narrow area near the edge 201 of the circuit board 20.

[0103] Second Embodiment The second embodiment of the present invention differs from the first embodiment in that the heat load of the light source device is reduced by not using a heat dissipation pad on the circuit board. Note that the description of the same points as in the first embodiment will be omitted or simplified.

[0104] 9(a) is a vertical cross-sectional view of a light source device 2 according to a second embodiment of the present invention. The light source device 2 includes a plurality of light emitting devices 50 (50a, 50b) each having a light emitting element 14 mounted on an element substrate 11 as a light source, and a circuit board 60 on which the plurality of light emitting devices 50 are mounted.

[0105] The light emitting device 50 differs from the light emitting device 10 according to the first embodiment in that it does not include a heat transfer pad 13. In each of the plurality of light emitting devices 50, the element substrate 11 includes an electrode pad 12 connected to the light emitting element 14. Hereinafter, the anode-side electrode pad 12 will be referred to as an anode electrode pad, and the cathode-side electrode pad 12 will be referred to as a cathode electrode pad.

[0106] In the light source device 2, one of the anode electrode pad and the cathode electrode pad (electrode pad 12a) is arranged closer to the light-emitting center position C of the plurality of light-emitting devices 50 than the other (electrode pad 12b). In all the light-emitting devices 50, when the anode electrode pad is electrode pad 12a, the cathode electrode pad is electrode pad 12b, and when the cathode electrode pad is electrode pad 12a, the anode electrode pad is electrode pad 12b.

[0107] The circuit board 60 includes circuit pads 22a connected to the electrode pads 12a of the plurality of light emitting devices 50, and circuit pads 22b connected to the electrode pads 12b of the plurality of light emitting devices 50. The electrode pads 12a of the plurality of light emitting devices 50 are commonly connected to one circuit pad 22a provided between the plurality of light emitting devices 50 on the circuit board 60. The circuit pad 22a is not a plurality of pads connected by wiring, but is a single continuous pad.

[0108] Fig. 9(b) is a schematic diagram showing the planar positional relationship between the electrode pads 12a, 12b and the light emitting element 14 of the light emitting devices 50a, 50b, and the circuit pad 22a of the circuit board 60. For example, when the light source device 2 is cut vertically along the cutting line AA shown in Fig. 9(b), the cross section shown in Fig. 9(a) appears.

[0109] In the example shown in Figures 9(a) and (b), both electrode pads 12a are located on the central side of the arrangement of the light-emitting devices 50a and 50b (towards the light-emitting center position C of the light-emitting devices 50a and 50b), and electrode pad 12b is located on the side away from the center.

[0110] Heat generated by the operation of the light emitting element 14 is mainly transmitted in this order from the light emitting element 14 to the electrode pad 12a, the bonding material 31, and the circuit pad 22a, and is then dissipated to the circuit board 60. Because the circuit pad 22a is one continuous wide pad, heat can be efficiently dissipated from the vicinity of the light emission center position C where heat from the light emitting element 14 is concentrated. Therefore, the light source device 2 has excellent thermal properties and reliability.

[0111] Furthermore, in this case, as shown in Figures 9(a) and (b), even if multiple light-emitting devices 50 are arranged so that the light-emitting elements 14 are close to each other in order to reduce the light-emitting area, heat can be efficiently dissipated through the electrode pads 12a arranged toward the center of the arrangement of the multiple light-emitting devices 50, thereby suppressing deterioration of the light-emitting elements 14 due to thermal load.

[0112] In the example shown in Figures 9(a) and (b), the light emitting devices 50a and 50b are arranged so that each light emitting element 14 is close to the light emitting center position C, and the light emitting area of ​​the light source device 2 is a relatively narrow area centered on the light emitting center position C located halfway between the two light emitting elements 14.

[0113] The smaller light-emitting area reduces uneven brightness and color of the light source device 2. Furthermore, the smaller light-emitting area improves the light-collection efficiency on the light control components when the light source device 2 is used in combination with the light-guiding components, light-receiving components, and other light control components.

[0114] In order to reduce the light-emitting area of ​​the light source device 2 by bringing the light-emitting elements 14 of the plurality of light-emitting devices 50 closer to each other, the interval between the plurality of light-emitting devices 50 (the interval between any two light-emitting devices 50 among the plurality of light-emitting devices 50) is preferably 0.5 mm or less, more preferably 0.3 mm or less, and even more preferably 0.1 mm or less. The light-emitting devices 50 may also be in contact with each other.

[0115] Furthermore, heat dissipation can be performed particularly efficiently when the light-emitting intensities of the multiple light-emitting devices 50 can be individually controlled. For example, when one of the light-emitting devices 50a and 50b is turned off, the turned-off device does not generate heat, so essentially only the turned-on device can use the circuit pad 22a for heat dissipation. Therefore, compared to when the light-emitting devices 10a and 10b are connected to independent pads, the area of ​​the pads available for heat dissipation is larger, allowing for more efficient heat dissipation. Similarly, when there is a difference in the light-emitting intensities of the light-emitting devices 50a and 50b, the device with the weaker light-emitting intensity generates less heat, so the heat from the device with the stronger light-emitting intensity can be efficiently dissipated to the circuit pad 22a.

[0116] 9(a), it is preferable that the circuit pads 22a provided on the circuit board 60 are connected to circuit pads 26a provided on the surface behind the mounting surface of the circuit board 60. By using the circuit pads 26a, it is possible to improve the heat dissipation effect from the back surface of the circuit board 60.

[0117] In order to further improve the heat dissipation effect, it is preferable that the circuit pads 22b are connected to circuit pads 26b provided on the surface behind the mounting surface of the circuit board 60, as shown in FIG. 9(a).

[0118] When circuit pads 26a and 26b are used, it is preferable that circuit pads 22a and 26a, and circuit pads 22b and 22b are connected via vias 25 that penetrate circuit board 60. In this case, heat is efficiently transferred to circuit pads 26a and 26b, and the heat dissipation effect from the back surface of circuit board 60 can be further improved.

[0119] The electrode pad 12a and the bonding material 31, and the bonding material 31 and the circuit pad 22a overlap in a plane in order to dissipate heat from the light emitting element 14. In order to dissipate heat from the light emitting element 14 more efficiently, it is preferable that the entire surface of the electrode pad 12a facing the bonding material 31 is covered with the bonding material 31, and that the entire surface of the bonding material 31 facing the circuit pad 22a is covered with the circuit pad 22a.

[0120] 9(a) and 9(b), light emitting devices 50a and 50b are illustrated as examples of the plurality of light emitting devices 50, and the electrode pads 12a of the light emitting devices 50a and 50b are commonly connected to a single circuit pad 22a. In the light source device 2, the number of the plurality of light emitting devices 50 whose electrode pads 12a are commonly connected to a single circuit pad 22a is, for example, two to four. If the number of the plurality of light emitting devices 50 is four or less, it is relatively easy to arrange the plurality of light emitting devices 50 so that each light emitting element 14 is close to the light emission center position C in order to reduce the light emission area. In addition, generally, the more light emitting elements are arranged closely, the greater the thermal load of the light emitting elements. Therefore, for example, when there are three or more light emitting devices 50 whose electrode pads 12a are commonly connected to a single circuit pad 22a, the effect of the light source device 2 in reducing the thermal load of the light emitting elements 14 becomes more significant.

[0121] Fig. 10(a) is a schematic diagram showing an example of an arrangement pattern of three light emitting devices 50a to 50c used as the plurality of light emitting devices 50. Fig. 10(b) is a schematic diagram showing an example of an arrangement pattern of four light emitting devices 50a to 50d used as the plurality of light emitting devices 50. Figs. 10(a) and 10(b) mainly show the positional relationship in the planar direction of each of the electrode pads 12a and light emitting elements 14 of the plurality of light emitting devices 50, and the circuit pads 22a of the circuit board 60.

[0122] In the example shown in Figures 10(a) and (b), multiple light-emitting devices 50 are arranged so that each light-emitting element 14 is close to the light-emitting center position C, and the light-emitting area is a relatively narrow region centered on the light-emitting center position C, which is located in the middle of the multiple light-emitting elements 14.

[0123] The light source device 2 may be configured such that the circuit board 60 is made up of a base material 21a made of an insulating material and a non-conductive pad 21b, as in the light source device 1 shown in FIG. 2(a).

[0124] In the light source device 2, when the circuit board 60 is a single-sided board like the light source device 1 shown in FIG. 2(c), an insulating layer 34 may be provided on the surface of the circuit board 60.

[0125] The light source device 2 may be configured such that the light emitting element 14 is sealed with a sealing material 15 in a light emitting device 50, like the light source device 1 shown in FIG. 3(a).

[0126] 3(b), the light source device 2 may have a wavelength conversion member 16 containing a phosphor disposed on the light emitting element 14 and sealed with a sealing material 15. For example, by setting the emission color of the light emitting element 14 to blue and the fluorescence color of the wavelength conversion member 16 to yellow, white light can be extracted from the light source device 2.

[0127] In the light source device 2, the emission colors of the multiple light emitting devices 50 may be the same or different. For example, when three light emitting devices 50 are used, the emission colors of all three light emitting devices 50 may be white, or the emission colors of the three light emitting devices 50 may be red, blue, and green (RBG), respectively. Alternatively, two light emitting devices 50 may have the same emission color and the remaining light emitting device 50 may have a different emission color. Furthermore, when the emission colors of the multiple light emitting devices 50 are different, power can be supplied to one light emitting device 50 to make the light source device 2 emit a single color, or power can be supplied to multiple light emitting devices 50 to make the light source device 2 emit a mixed color.

[0128] Furthermore, according to this embodiment, it is possible to provide a lighting device, for example, an in-vehicle lighting device, that includes a light source device 2 that can emit monochromatic light, mixed-color light, white light, etc. using a plurality of light-emitting devices 50, and a light-guiding component that guides the light emitted from the light source device 2.

[0129] The arrangement of the electrode pads 12a and 12b in the light-emitting device 50 is not particularly limited. For example, in the examples shown in Figures 9 and 10, the electrode pads 12a and 12b are arranged in the short direction of the planar shape of the element substrate 11, but the electrode pads 12a and 12b may also be arranged in the long direction of the planar shape of the element substrate 11. Figures 11(a) to 11(c) are schematic diagrams showing examples of arrangement patterns of two to four light-emitting devices 50 when the electrode pads 12a and 12b are arranged in the long direction of the planar shape of the element substrate 11.

[0130] (Variation) 12(a) is a vertical cross-sectional view of a light source device 3 which is a modified example of the light source device 2 according to the second embodiment of the present invention. The light source device 3 differs from the light source device 2 in that it uses a plurality of light emitting devices 10 (10a, 10b) each having a heat transfer pad 13 provided on an element substrate 11.

[0131] In each of the plurality of light emitting devices 10, the element substrate 11 includes electrode pads 12 (12a, 12b) connected to the light emitting elements 14 and heat transfer pads 13 insulated from the light emitting elements 14.

[0132] In the light source device 3, similarly to the light source device 2, the electrode pad 12a, which is one of the anode electrode pad and the cathode electrode pad, is arranged closer to the light emission center position C of the plurality of light emitting devices 50 than the other electrode pad 12b.

[0133] The circuit board 20 has circuit pads 22 (22a, 22b) connected to the electrode pads 12 (12a, 12b) of the plurality of light emitting devices 10. The electrode pads 12a and heat transfer pads 13 of the plurality of light emitting devices 10 are commonly connected to one circuit pad 22a provided between the plurality of light emitting devices 10 on the circuit board 20.

[0134] Fig. 12(b) is a schematic diagram showing the planar positional relationship between the electrode pads 12a, 12b, heat transfer pad 13, and light emitting element 14 of the light emitting devices 10a, 10b, and the circuit pad 22a of the circuit board 20. For example, when the light source device 3 is cut vertically along the cutting line BB shown in Fig. 12(b), the cross section shown in Fig. 12(a) appears.

[0135] In the example shown in Figures 12(a) and (b), both electrode pads 12a are located on the central side of the arrangement of the light-emitting devices 10a and 10b (towards the light-emitting center position C of the light-emitting devices 10a and 10b), and electrode pad 12b is located on the side away from the center.

[0136] Heat generated by the operation of the light emitting element 14 is dissipated to the circuit board 20 mainly through a path that travels from the light emitting element 14 to the electrode pad 12a, the bonding material 31, and the circuit pad 22a in this order, and a path that travels from the light emitting element 14 to the heat transfer pad 13, the bonding material 32, and the circuit pad 22a in this order. Because the circuit pad 22a is one continuous wide pad, heat can be efficiently dissipated from the vicinity of the light emission center position C where heat from the light emitting element 14 is concentrated. Therefore, the light source device 3 has excellent thermal properties and reliability.

[0137] In order to dissipate heat from the light-emitting element 14, the electrode pad 12a and the bonding material 31, the bonding material 31 and the circuit pad 22a, the heat transfer pad 13 and the bonding material 32, and the bonding material 32 and the circuit pad 22a overlap in a plane. In order to dissipate heat from the light-emitting element 14 more efficiently, it is preferable that the entire surface of the electrode pad 12a facing the bonding material 31 is covered with the bonding material 31 and the entire surface of the bonding material 31 facing the circuit pad 22a is covered with the circuit pad 22a, and it is also preferable that the entire surface of the heat transfer pad 13 facing the bonding material 32 is covered with the bonding material 32 and the entire surface of the bonding material 32 facing the circuit pad 22a is covered with the circuit pad 22a.

[0138] 12(b), in the light emitting device 10, it is preferable that the light emitting element 14 is arranged on the element substrate 11 so that the area overlapping with the heat transfer pad 13 is larger than the area overlapping with the two electrode pads 12 (12a, 12b) in a plan view. This allows heat to be efficiently dissipated from the heat transfer pad 13, which is dedicated to heat dissipation.

[0139] In FIGS. 12(a) and 12(b), light-emitting devices 10a and 10b are shown as examples of the plurality of light-emitting devices 10, and the electrode pads 12a and heat-transfer pads 13 of the light-emitting devices 10a and 10b are commonly connected to a single circuit pad 22a. In the light source device 3, the number of the plurality of light-emitting devices 10 whose electrode pads 12a and heat-transfer pads 13 are commonly connected to a single circuit pad 22a may be, for example, two to four. If the number of the plurality of light-emitting devices 10 is four or less, it is relatively easy to arrange the plurality of light-emitting devices 50 so that each light-emitting element 14 is close to the light-emitting center position C in order to reduce the light-emitting area. Furthermore, generally, the more light-emitting elements are arranged closely, the greater the thermal load of the light-emitting elements. Therefore, for example, when there are three or more light-emitting devices 10 whose electrode pads 12a and heat-transfer pads 13 are commonly connected to a single circuit pad 22a, the effect of the light source device 2 in reducing the thermal load of the light-emitting elements 14 becomes more significant.

[0140] Fig. 13(a) is a schematic diagram showing an example of an arrangement pattern of three light emitting devices 10a to 10c used as the plurality of light emitting devices 10. Fig. 13(b) is a schematic diagram showing an example of an arrangement pattern of four light emitting devices 10a to 10d used as the plurality of light emitting devices 10. Figs. 13(a) and 13(b) mainly show the positional relationship in the planar direction of the electrode pads 12a, heat transfer pads 13, and light emitting elements 14 of each of the plurality of light emitting devices 10, and the circuit pads 22a of the circuit board 20.

[0141] In the example shown in Figures 13(a) and (b), multiple light-emitting devices 10 are arranged so that each light-emitting element 14 is close to the light-emitting center position C, and the light-emitting area is a relatively narrow region centered on the light-emitting center position C, which is located in the middle of the multiple light-emitting elements 14.

[0142] (Effects of the second embodiment) In the light source device 2 according to the second embodiment of the present invention, the electrode pads 12a of the plurality of light emitting devices 50 are commonly connected to the circuit pads 22a of the circuit board 60, and therefore the light emitting elements 14, which are the light source, have excellent heat dissipation properties, and the thermal load can be reduced even when the plurality of light emitting elements 14 are located close to each other.

[0143] Similarly, in the light source device 3, the electrode pads 12a and heat transfer pads 13 of the multiple light emitting devices 10 are commonly connected to the circuit pads 22a of the circuit board 20, so that the light emitting elements 14, which are the light source, have excellent heat dissipation properties, and the thermal load can be reduced even when multiple light emitting elements 14 are close to each other.

[0144] Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments and various modifications can be made without departing from the spirit of the invention. Furthermore, the components of the above-described embodiments can be combined in any manner without departing from the spirit of the invention.

[0145] Furthermore, the above-described embodiments do not limit the scope of the invention as claimed, and it should be noted that not all of the combinations of features described in the embodiments are necessarily essential to the means for solving the problems of the invention. [Explanation of symbols]

[0146] 1, 2, 3 Light source device 10a, 10b, 10c, 10d Light-emitting device 11 Element substrate 12, 12a, 12b electrode pads 13 Heat transfer pad 14 Light-emitting element 20 Circuit Board 22, 22a, 22b Circuit pads 23, 24 Heat dissipation pad 25 Beer 50a, 50b, 50c, 50d Light-emitting device 60 Circuit Board 1a Light source device 10x, 10y light emitting device 40 Luminous Emblem 41 Ornaments

Claims

1. a plurality of light emitting devices each having a light emitting element mounted on an element substrate as a light source; a circuit board on which the plurality of light emitting devices are mounted; Equipped with In each of the plurality of light emitting devices, the element substrate includes an electrode pad connected to the light emitting element and a heat transfer pad insulated from the light emitting element, the circuit board includes circuit pads connected to the electrode pads of the plurality of light-emitting devices and heat dissipation pads insulated from the electrode pads of the plurality of light-emitting devices, the heat transfer pads of the plurality of light emitting devices are commonly connected to the heat dissipation pad of the circuit board; Light source device.

2. The plurality of light emitting devices are arranged such that the distance between the heat transfer pads is shorter than the distance between the electrode pads. The light source device according to claim 1 .

3. the heat dissipation pads include first pads provided on a mounting surface of the circuit board on which the plurality of light emitting devices are mounted, and second pads provided on a surface behind the mounting surface; 3. The light source device according to claim 1.

4. the first pad and the second pad are connected through a via that penetrates the circuit board; The light source device according to claim 3 .

5. Among the plurality of light emitting devices, some light emitting devices have lighting timings different from other light emitting devices.

3. The light source device according to claim 1.

6. the partial light-emitting device and the other light-emitting device have different emission wavelengths; The light source device according to claim 5 .

7. The heat dissipation pad has a strip-like planar shape, the plurality of light emitting devices include a plurality of first light emitting devices arranged along the length direction of the planar shape on one side of the width direction of the planar shape of the heat dissipation pad, and a plurality of second light emitting devices arranged along the length direction of the planar shape on the other side of the width direction of the planar shape of the heat dissipation pad, the plurality of first light emitting devices and the plurality of second light emitting devices are electrically connected in series via the plurality of circuit pads arranged along the length direction of the planar shape; The light source device according to claim 1 .

8. the plurality of first light-emitting devices and the plurality of second light-emitting devices have different amounts of heat generation; The light source device according to claim 7 .

9. The light source device according to claim 7 ; an ornament having a light transmitting region for transmitting light emitted from the light source device from the back surface side to the front surface side; Equipped with In the light source device, the plurality of light emitting devices are arranged side by side along an edge of the circuit board such that the plurality of first light emitting devices are located on an inner side and the plurality of second light emitting devices are located on an outer side. Luminous emblem.

10. the heat generation amount of the plurality of first light-emitting devices is higher than the heat generation amount of the plurality of second light-emitting devices; 10. The luminous emblem according to claim 9.

11. a CIE standard spectral luminous efficiency for photopic vision at an emission peak wavelength of the first light-emitting device is higher than a CIE standard spectral luminous efficiency for photopic vision at an emission peak wavelength of the second light-emitting device; a CIE standard spectral luminous efficiency for scotopic vision at an emission peak wavelength of the second light-emitting device is higher than a CIE standard spectral luminous efficiency for scotopic vision at an emission peak wavelength of the first light-emitting device; 11. The luminous emblem according to claim 9 or 10.

12. a plurality of light emitting devices each having a light emitting element mounted on an element substrate as a light source; a circuit board on which the plurality of light emitting devices are mounted; Equipped with In each of the plurality of light-emitting devices, the element substrate includes an anode electrode pad and a cathode electrode pad connected to the light-emitting element, each of the plurality of light emitting devices is arranged such that a first electrode pad, which is one of the anode electrode pad and the cathode electrode pad, is closer to a light emitting center position of the plurality of light emitting devices than a second electrode pad, which is the other of the anode electrode pad and the cathode electrode pad; the first electrode pads of the plurality of light emitting devices are commonly connected to one first circuit pad provided on the circuit board; Light source device.

13. the plurality of light-emitting devices are three or more of the light-emitting devices; The light source device according to claim 12.

14. the distance between any two of the plurality of light-emitting devices is 0.5 mm or less; 14. The light source device according to claim 12 or 13.

15. In each of the plurality of light emitting devices, the element substrate includes a heat transfer pad insulated from the light emitting element, the heat transfer pads of the plurality of light emitting devices are commonly connected to the first circuit pad; 14. The light source device according to claim 12 or 13.

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