JP2019153723A - Light source module - Google Patents

Abstract

To provide a light source module with high vehicle environment and high reliability against heat generation.SOLUTION: The light source module 1 is formed by integrally mounting a luminous element (a micro LED) 10 on a driver IC 20, and the luminous element 10 and the driver IC are sealed with resin 50 under a state where a luminous surface 11 of the luminous element 10 is exposed. The driver IC20 is mounted on a base 30 and installed on a heat sink 111. Desirably, there is provided an attachment 40 electrically connected with the base 30 for electrical connection with an external power supply and control system.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a light source module having a structure in which a light emitting element such as an LED (light emitting diode), particularly a chip type light emitting element, is mounted on a driver IC (integrated circuit).

  In recent years, it has been proposed to apply LED arrays, particularly light-emitting elements composed of semiconductors such as micro LEDs, to display devices. Also, in a vehicle lamp, the use of this type of light emitting element as a light source has been studied. When such a light emitting element is used as a light source, the light emitting element formed on a chip of a required size is mounted on a driver IC for driving the light emitting element, and the two are integrated to constitute a light source module. It is preferable.

  For example, Patent Document 1 discloses a technique for configuring a light emitting display device by mounting an LED array as a light emitting element on a driver IC. Here, the LED array is flip-chip mounted on the upper surface of the driver IC to integrate them.

JP 11-214753 A

  In an apparatus including a normal semiconductor chip, the semiconductor chip is sealed and packaged with resin, ceramic, or the like in order to improve reliability. However, since it is necessary to emit light from the surface of the light emitting element chip, that is, the light emitting surface, it is difficult to package. Japanese Patent Application Laid-Open No. H10-228561 does not describe the packaging of the light emitting element chip and the driver IC integrally.

  Thus, when a light source module is configured including a light emitting element, it is difficult to package with a resin or ceramic. Therefore, when an unpackaged light source module is applied to a vehicle lamp, there arises a problem that it is difficult to maintain reliability against severe vehicle environments such as temperature, humidity, vibration, and impact.

  Further, even if a light emitting element or a driver IC is packaged, heat generation of the light emitting element becomes a problem. There is a possibility that heat dissipation generated by packaging the light emitting element is hindered by the package. If the heat radiation is not sufficient, the light emitting element such as an LED has a problem that the light emission characteristic is deteriorated by so-called thermal runaway, and the reliability of the light source module is lowered.

  An object of the present invention is to provide a light source module with improved reliability against vehicle environment and heat generation.

  The present invention is a light source module including a chip-shaped light emitting element and a driver device for driving the light emitting element, and the light emitting element is integrally mounted on the driver device, and the light emitting surface of the light emitting element is exposed. In the state, the light emitting element and the driver device are sealed with a sealing material.

  In the present invention, it is preferable to include a base on which the driver IC is mounted, the base is attached to a heat sink, and the sealing material is disposed on the base. Moreover, it is preferable that an attachment that is electrically connected to the wiring of the base is provided, and that the attachment is provided with a connector that is electrically connected to an external power supply / control system.

  According to the present invention, by sealing the light emitting element and the driver device with a sealing material, the light source module can be protected from the vehicle environment and reliability can be improved even when the light source module is applied to a vehicle. In the case of resin sealing, by mounting a driver measure with a light emitting element mounted on a base and fixing the base to a heat sink, the heat radiation effect of the light source module can be enhanced and the reliability can be increased.

Sectional drawing of the headlamp to which the light source module is applied. FIG. 3 is a cross-sectional view of the light source module according to the first embodiment. FIG. 3 is a schematic partial exploded perspective view of the light source module according to the first embodiment. The schematic diagram explaining the circuit structure of micro LED and driver IC. Sectional drawing of the light source module of Embodiment 2. FIG. Sectional drawing of the light source module of Embodiment 3. FIG.

(Embodiment 1)
Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic sectional view of an automobile headlamp to which a light source module of the present invention is applied. A lamp unit 110 is housed in the lamp housing 100 of the headlamp HL, and is supported by the lamp body 101. The light emitted from the lamp unit 110 is transmitted through the translucent cover 102 of the lamp housing 100 and is irradiated to the front area of the automobile.

  The lamp unit 110 includes the light source module 1 according to the present invention. By controlling the light emission of the light source module 1, some areas are shielded from light so as not to dazzle oncoming cars and preceding cars, and other areas. It is configured as a lamp unit capable of ADB (Adaptive Driving Beam) control that illuminates a wide area.

  The lamp unit 110 includes a heat sink 111 that fixes and supports the light source module 1 and a projection lens 112 that projects light emitted from the light source module 1 onto a front area of the automobile. The projection lens 112 is supported by a cylindrical lens holder 113 supported by the heat sink 111.

  A power source / control system 200 is connected to the light source module 1. The power supply / control system 200 includes a power supply unit 201 that supplies power to the light source module 1 using the in-vehicle battery 202 as a power supply, and a control unit 210 that controls a current supplied to the light source module 1. The power supply unit 201 is constituted by, for example, a DC-DC switching converter. Here, the control unit 210 is composed of a control ECU equipped in an automobile. An imaging camera 211 as a monitoring sensor is connected to the control ECU 210. The current of the light source module 1 is controlled based on an external image captured by the imaging camera 211, and the ADB control described above is executed.

  2 is a sectional view of the light source module 1, and FIG. 3 is a partially exploded schematic perspective view thereof. In the following, the vertical direction is based on FIG. 2, but this vertical direction corresponds to the front-rear direction along the optical axis Lx of the lamp unit 110 in FIG. The light source module 1 includes a chip-shaped light emitting element 10, a driver IC (integrated circuit device) 20 on which the light emitting element 10 is mounted, and a base 30 on which the driver IC 20 is mounted. The base 30 is fixed to the heat sink 111 of the lamp unit 110.

  The light emitting element 10 includes a chip-like LED array in which a plurality of LEDs are integrally arranged, here, a micro LED. A plurality of LEDs are arranged on the upper surface of the micro LED 10, and the upper surface of the micro LED is configured as a light emitting surface 11. A plurality of mounting bumps 12 are disposed on the lower surface of the micro LED 10. These mounting bumps 12 are connected to the plurality of LEDs, respectively, and are arranged in a grid of n × m (n and m are integers of 2 or more) here.

  The driver IC 20 is configured as a semiconductor device in which a plurality of transistor elements are monolithically formed as will be described later. The plurality of transistor elements constitute a current drive circuit that supplies a drive current to each of the plurality of LEDs constituting the micro LED 10. A plurality of mounting pads 21 are disposed on the upper surface of the driver IC 20 by a conductive film, and a plurality of mounting bumps 22 are formed on the lower surface. The mounting pads 21 are arranged corresponding to the mounting bumps 12 of the micro LED 10, and the conductive bumps 22 are arranged along the periphery of the driver IC 20.

  The base 30 is formed in a flat plate shape with an insulating material having high thermal conductivity, for example, ceramics such as aluminum nitride and aluminum oxide. The base 30 is fixed with its lower surface in close contact with the upper surface of the heat sink 111. A conductive pattern having a required shape is formed on the upper surface of the base 30. This conductive pattern is disposed in the central region of the upper surface of the base 30 to provide electrical connection between a plurality of mounting pads 31 for mounting the driver IC 20 and an attachment 40 described later disposed in the peripheral region of the upper surface. An input / output pad 32 for performing the connection and a connecting portion 33 for electrically connecting the mounting pad 31 and the input / output pad 32 to each other are provided. The mounting pads 31 are arranged corresponding to the mounting bumps 22 of the driver IC 20.

  In the light source module 1, the driver IC 20 is mounted on the upper surface of the base 30 by a flip chip method. That is, the mounting bumps 22 on the lower surface of the driver IC 20 are joined to the mounting pads 31 on the upper surface of the base 30, so that they are integrated and electrically connected to each other. Further, the micro LED 10 is mounted on the driver IC 20 by a flip chip method. That is, the mounting bumps 12 on the lower surface of the micro LED 10 are joined to the mounting pads 21 on the upper surface of the driver IC 20 so that they are integrated and electrically connected to each other.

  Then, as shown in FIG. 2, the sealing resin 50 is applied to the upper surface of the micro LED 10, that is, the region excluding the light emitting surface 11, here, the region that completely covers the driver IC 20 from the side surface region of the micro LED 10. A package is formed in which these regions are sealed with the resin 50. Here, silicone is used as the sealing resin 50. The resin 50 seals the upper surface of the base 30, but does not adhere to the peripheral region of the upper surface of the base 30, that is, the region where the input / output pad 32 is formed. Reference numeral 32 denotes an exposed state.

  As a process for sealing the resin 50, for example, a resin potting method in which a sol-like resin is applied so as to cover the driver IC 20 while being discharged from a nozzle (not shown) and then cured can be employed. Alternatively, a mold frame (not shown) is temporarily placed on the base 30 so as to surround the driver IC 20, and then the mold frame is filled with a fluid resin and cured, and then the mold frame is removed. May be. Alternatively, a method in which a resin formed in advance in a predetermined shape is bonded so as to cover the driver IC 20 with an adhesive or the like. In any case, any method may be used as long as the driver IC is sealed in a liquid-tight or air-tight state with resin.

  Further, an attachment 40 is fixed to the upper surface of the heat sink 111 so as to surround the base 30. The attachment 40 is formed as a rectangular frame 41 by an insulating material such as a resin, and is fixed to the heat sink 111 with screws 43 at support pieces 42 provided at a plurality of locations on the lower edge of the frame 41. . Further, a top plate provided with an opening window so as not to affect the light emitted from the micro LED 10, in other words, a ceiling plate 44, is formed on the upper edge portion of the frame 41. A connector housing 45 having a rectangular tube shape that is open toward the side is integrally formed in a part of the circumferential direction.

  In addition, a conductive material such as metal is integrally formed on the frame 41 by, for example, insert molding. A part of the conductive material is arranged in the connector housing 45 and is configured as a connector terminal 46 for electrical connection to an external connector (not shown). A plurality of other portions of the conductive material are arranged in the circumferential direction along the inner surface of the flange plate 44, and are configured as contact pieces 47 whose tips protrude and extend downward. The connector terminal 46 and the contact piece 47 are electrically connected to each other.

  By fixing the attachment 40 to the heat sink 111, the contact piece 47 is brought into contact with the input / output pad 32 exposed to the peripheral region of the base 30 by its own elasticity, and is electrically connected to each other. Further, the connector terminal 46 is electrically connected to an external connector fitted to the connector housing 45. The external connector is electrically connected to the power supply unit 201 and the control ECU 210 shown in FIG. 1, and the power supply / control system 200 is electrically connected to the light source module 1 by being electrically connected to the connector terminal 46.

  FIG. 4 is a schematic diagram showing an example of the circuit configuration of the micro LED 10 and the driver IC 20. A plurality of LEDs are arranged in the micro LED 10 as described above, and power is supplied from the power supply unit 201 via the mounting bump 12, the mounting pad 21, and the mounting pad 22. The driver IC 20 is configured as a current drive circuit, for example, a current mirror circuit including transistors Tr1 and Tr2. The driver IC 20 controls the base current of the transistor Tr3 by a control signal output from the control ECU 210 via the mounting bumps 22, and the current The operation of the mirror circuit is turned on and off, and the current of the transistor Tr2 is controlled. As a result, the current supplied to the LEDs connected to the transistor Tr2 is controlled, and the light emission of each LED is controlled individually or collectively at a predetermined number.

  As shown in FIG. 1, when the light source module 1 of this embodiment is fixed to the heat sink 111, the light emitting surface 11 of the micro LED 10 is directed to the front of the lamp unit 110. Then, the light emission of the plurality of LEDs of the micro LED 10 is controlled by the control of the control ECU 210, and the light emitted from each LED is projected onto the front area of the automobile by the projection lens 112. Although a detailed description is omitted, since the plurality of LEDs correspond to the respective parts of the front area of the automobile, the front area corresponding to the emitted LED is irradiated with light, and illumination with a required light distribution is executed. Is done.

  Therefore, another vehicle existing in the front area of the vehicle, that is, a preceding vehicle or an oncoming vehicle is detected by the imaging camera 211 shown in FIG. 1, and a required control signal is output from the control ECU 210 to the driver IC 20 based on this detection. The driver IC 20 extinguishes or dimmes the LED corresponding to the area where the detected other vehicle is present among the LEDs of the micro LED 10, so that the other area is brightly illuminated without being dazzled. Control is executed.

  In the light source module 1, the micro LED 10 and the driver IC 20 are hermetically or liquid-tightly sealed with a resin 50 so as not to interfere with the light emission of the micro LED 10, so that the package is configured. Can be protected from severe external environment. That is, suitable ADB control can be realized by protecting the LED of the micro LED 10 and the transistor element of the driver IC 20 from temperature change, humidity change, vibration, impact, etc., and performing stable current control.

  In addition, the driver IC 20 and the micro LED 10 are covered with the frame 41 and the cover 44 of the attachment 40 within a range that does not affect the light emission from the micro LED 10, so that the external area is protected from external impact. It is also effective in protecting the environment.

  The micro LED 10 generates heat as it emits light, but the heat on the light emitting surface side is radiated through the opening window of the attachment 40 and dissipated. Further, the heat on the opposite lower surface side is transferred from the driver IC 20 to the base 30 and further transferred to the heat sink 111 to be radiated. Since the base 30 is made of ceramics having high thermal conductivity, a high heat dissipation effect is obtained, and thermal reliability in the micro LED 10 and the driver IC 20 is ensured.

(Embodiment 2)
FIG. 5 is a cross-sectional view of the light source module 1A according to the second embodiment. Main parts having the same configurations as those of the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted. The driver IC 20 is mounted on the base 30A fixed to the heat sink 111 of the lamp unit, and the micro LED 10 is mounted on the upper surface of the driver IC 20. Further, the driver IC 20 and the micro LED 10 are packaged with a sealing resin 50, and are electrically connected to the base 30 by an attachment 40A fixed to the heat sink 111.

  Here, in Embodiment 2, the base 30 </ b> A is formed in a shallow dish container shape having a peripheral wall 34. A required conductive pattern is formed by a conductive film on the inner surface side of the base 30A, the mounting pads 31 are disposed on the inner bottom surface of the base 30A by this wiring pattern, and the input / output pads 32 are disposed on the upper surface of the peripheral wall 34. Has been. The height dimension of the base 30 </ b> A is set so that the upper surface of the peripheral wall 34 is at a height position substantially equal to or slightly lower than the light emitting surface of the micro LED 10.

  As in the first embodiment, the driver IC 20 and the micro LED 10 are mounted and mounted on the inner bottom surface of the base 30A. The mounting and mounting configurations in these are the same as those in the first embodiment. The inside including the inner bottom surface of the base 30 </ b> A is filled with a sealing resin 50, and the entire driver IC 20 and the peripheral area of the micro LED 10 are sealed by the resin 50.

  In the second embodiment, since the package of the micro LED 10 and the driver IC 20 can be realized by filling the container-shaped base 30A with the sealing resin 50, compared with the resin sealing process in the first embodiment. Sealing can be performed easily. Further, the resin 50 does not lose its shape due to impact or vibration, and the reliability of the package is improved. Furthermore, since the contact area between the resin 50 and the base 30A can be made larger than that in the first embodiment, a part of the heat generated in the micro LED 10 is transferred to the base through the resin 50. The heat dissipation effect can be further increased by increasing the heat dissipation effect as compared with the first mode.

(Embodiment 3)
FIG. 6 is a cross-sectional view of the light source module 1B of the third embodiment. The third embodiment corresponds to a modification of the second embodiment, and the driver IC 20 has no mounting bump formed on the lower surface, and a bonding pad 23 is disposed on the periphery of the upper surface. In addition, the base 30B has a two-stage peripheral wall 34, and a mounting pad 31 is formed on the upper surface on the inner low side, and an input / output pad 32 is formed on the upper surface on the outer high side.

  The driver IC 20 is mounted on the inner bottom surface of the base 30B by bonding or bonding, and the bonding pad 23 and the mounting pad 31 of the base 30B are electrically connected by a bonding wire 24. The base 30B is filled with a sealing resin 50 as in the second embodiment, and the micro LED 10, the driver IC 20, and the bonding wire 24 are sealed to form a package.

  The attachment 40B has substantially the same configuration as that of the second embodiment, and the connector electrode 46 and the contact piece 47 are formed by a conductive material insert-molded in the frame body 41. Further, the attachment 40B is provided with a cover 48 made of a conductive material so as to cover the flange plate 44. The cover 48 is provided independently of the conductive material forming the contact piece 47. The front end of the cover 48 extends to the vicinity of the periphery of the micro LED 10 and functions as a shield that electromagnetically shields at least the upper region of the driver IC 20. The cover 48 may be extended to the outer surface of the peripheral wall 34, which is advantageous in electromagnetically shielding the side region of the driver IC 20 as well.

  In the third embodiment, since the micro LED 10, the driver IC 20, and the bonding wire 24 are sealed by the package resin 50, these are protected from the external environment and the reliability is improved. In the third embodiment, when the transistor element of the current control circuit configured in the driver IC 20 illustrated in FIG. 4 is configured by a MOS transistor, the MOS transistor is externally connected by an electromagnetic shielding effect in the cover 48. It can be protected from electromagnetic waves and static electricity. As a result, the electrical reliability of the driver IC 20 can be improved.

  In the present invention, each of the embodiments described above exemplifies a micro LED as a light emitting element, but may be a light source module in which an LED array, a semiconductor laser, an organic EL, and the like are mounted on a driver IC. In addition, the light emitting element and the driver IC in the present invention are not limited to one each, and may be a light source module including a plurality of light emitting elements and a driver IC, and these may be packaged integrally or individually. It may be configured.

  In the present invention, the configuration for electrical connection to the input / output pads provided on the base is not necessarily the configuration using the attachment described in the embodiment. For example, a connector is provided on the base and an external power supply / control is provided. It may be configured to be electrically connected to the system.

  In the present invention, the driver IC may be configured as a hybrid IC in which an electronic component is mounted on an insulating substrate. Further, the driver IC is not only provided with a circuit for driving a current supplied to the light emitting element, but also supplied to the light emitting element. A configuration including a part of a control circuit for controlling electric power may be used.

1 Light source module 10 Light emitting element (micro LED)
20 Driver IC (Driver Device)
30, 30A, 30B Base 40, 40A, 40B Attachment 50 Resin (sealing material)
111 Heat Sink 200 Power Supply / Control System 201 Power Supply Unit 210 Control ECU

Claims (8)

  A light source module comprising a chip-like light emitting element and a driver device for driving the light emitting element, wherein the light emitting element is integrally mounted on the driver device, wherein the light emitting surface of the light emitting element is exposed. A light source module, wherein a light emitting element and the driver device are sealed with a sealing material.   The light source module according to claim 1, further comprising a base on which the driver device is mounted, the base being attached to a heat sink, and the sealing material being disposed on the base.   The light source module according to claim 1, wherein the driver device is configured as a driver IC in which a circuit for driving a light emitting element is integrated, and the light emitting element is mounted on the driver IC by a flip chip.   The light source module according to claim 3, wherein the base includes a wiring electrically connected to the driver IC, and is electrically connected to an external power supply / control system via the wiring.   The light source module according to claim 4, further comprising an attachment electrically connected to the wiring of the base, and the attachment including a connector electrically connected to the external power supply / control system.   6. The light source module according to claim 3, wherein the driver IC is mounted on the base by flip chip.   6. The light source module according to claim 3, wherein the driver IC is mounted on the base by wire bonding. The light source module according to claim 1, wherein the sealing material is a resin material.

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