WO2019172240A1

WO2019172240A1 - Light source module

Info

Publication number: WO2019172240A1
Application number: PCT/JP2019/008601
Authority: WO
Inventors: 知幸市川
Original assignee: 株式会社小糸製作所
Priority date: 2018-03-06
Filing date: 2019-03-05
Publication date: 2019-09-12
Also published as: CN111801807A; JP2019153723A

Abstract

In this light source module (1) in which a light-emitting element (10) is integrally mounted to a driver IC (20), the light-emitting element (10) and the driver IC (20) are sealed with a resin (50) in a state in which a light-emitting surface (11) of the light-emitting element (10) is exposed.

Description

Light source module

The present disclosure 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.

Japanese Laid-Open Patent Publication No. 11-214753

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 the light emitting element chip. Japanese Patent Application Laid-Open No. H10-228561 does not describe the packaging of the light emitting element chip and the driver IC integrally.

As described above, when a light source module is configured to include a light emitting element, it is difficult to package with a resin or ceramic, so that it is conceivable to apply an unpackaged light source module to a vehicle lamp.
However, when an unpackaged light source module is applied to a vehicle lamp, there arises a problem that it is difficult to maintain reliability in a severe vehicle environment. The severe vehicle environment is, for example, temperature, humidity, vibration, impact, or the like.

Also, even if a light emitting element or a driver IC is packaged, heat generation of the light emitting element becomes a problem. In other words, heat dissipation generated by packaging the light emitting element may be hindered by the package. If the heat radiation of the light-emitting element is not sufficiently performed, the light-emitting element such as an LED has a problem that the light emission characteristic is lowered due to so-called thermal runaway, and the reliability of the light source module is lowered.

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

A light source module according to an aspect of the present disclosure includes a chip-shaped light emitting element and a driver device that drives the light emitting element, and the light emitting element is integrally mounted on the driver device, and the light emitting element includes: The light emitting element and the driver device are sealed with a sealing material with the light emitting surface exposed.

According to the present disclosure, by sealing the light emitting element and the driver device with the 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 the vehicle. Further, in the case of sealing with resin, by mounting the driver device on which the light emitting element is mounted on the base, and further fixing the base to the heat sink, the heat radiation effect of the light source module can be enhanced and the reliability can be increased.

It is sectional drawing of the headlamp to which the light source module is applied. 2 is a cross-sectional view of the light source module of Embodiment 1. FIG. FIG. 3 is an exploded perspective view of a schematic part of the light source module according to the first embodiment. It is a schematic diagram explaining the circuit structure of a light emitting element and the circuit structure of a driver IC. It is sectional drawing of the light source module of Embodiment 2. FIG. It is sectional drawing of the light source module of Embodiment 3. FIG.

(Embodiment 1)
Next, an embodiment of the present disclosure will be described with reference to the drawings. FIG. 1 is a schematic cross-sectional view of an automobile headlamp to which the light source module of the present disclosure 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 passes 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 disclosure. The lamp unit 110 controls the light emission of the light source module 1, thereby blocking ADB (Adaptive Driving Beam) control that blocks a part of the area so as not to dazzle the oncoming car and the preceding car and illuminates the other area over a wide area. Is possible.

The lamp unit 110 includes a heat sink 111, a projection lens 112, and a lens holder 113. The heat sink 111 fixedly supports the light source module 1. The projection lens 112 projects the light emitted from the light source module 1 onto the front area of the automobile. The projection lens 112 is supported by a cylindrical lens holder 113. The lens holder 113 is 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 and a control unit 210. The power supply unit 201 supplies power to the light source module 1 using the in-vehicle battery 202 as a power source. The controller 210 controls the current supplied to the light source module 1. The power supply unit 201 is configured by, for example, a DC-DC switching converter. In this example, the control unit 210 is composed of a control ECU provided in the automobile. An imaging camera 211 as a monitoring sensor is connected to the control unit 210. The control unit 210 controls the current of the light source module 1 based on the external image captured by the imaging camera 211, and executes the above-described ADB control.

FIG. 2 is a sectional view of the light source module 1. FIG. 3 is an exploded perspective view of a schematic part of the light source module 1. In the following, the vertical direction will be described with reference to FIG. The vertical direction in FIG. 2 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-like light emitting element 10, a driver IC (Integrated Circuit) 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 is composed of a chip-shaped LED array in which a plurality of LEDs are integrally arranged. The LED array is a micro LED in this example. A plurality of LEDs are arranged on the upper surface of the light emitting element 10. The upper surface of the light emitting element 10 is configured as a light emitting surface 11. A plurality of mounting bumps 12 are disposed on the lower surface of the light emitting element 10. These mounting bumps 12 are connected to a plurality of LEDs, respectively. The mounting bumps 12 are arranged in a two-dimensional shape of n × m (n and m are integers of 2 or more) in this example.

The driver IC 20 is an example of a driver device that drives a light emitting element. The driver IC 20 includes an integrated circuit in which a circuit for driving the light emitting element 10 is integrated. As will be described later, the driver IC 20 is configured as a semiconductor device in which a plurality of transistor elements are monolithically formed. The plurality of transistor elements constitute a current drive circuit that supplies a drive current to each of the plurality of LEDs constituting the light emitting element 10. The driver IC 20 has a plurality of mounting pads 21 formed on the upper surface by a conductive film and a plurality of mounting bumps 22 formed on the lower surface. The mounting pads 21 are arranged corresponding to the mounting bumps 12 of the light emitting element 10, and the mounting 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. An insulating material with high thermal conductivity is ceramics, such as aluminum nitride and aluminum oxide, for example. The base 30 is fixed to the heat sink 111 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. The conductive pattern includes a mounting pad 31 for mounting the driver IC 20, an input / output pad 32, and a connection portion 33 for electrically connecting the mounting pad 31 and the input / output pad 32 to each other. A plurality of mounting pads 31 are arranged in the central region of the upper surface of the base 30. The input / output pad 32 is disposed in a peripheral region on the upper surface of the base 30. The input / output pad 32 is electrically connected to an attachment 40 described later. The positions of the mounting pads 31 arranged on the upper surface of the base 30 correspond to the positions of the mounting bumps 22 of the driver IC 20.

In forming 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. As described above, the conductive pattern of the required shape of the base 30 (in this example, the mounting pad 31, the input / output pad 32, and the connecting portion 33) functions as a wiring that is electrically connected to the driver IC 20.
Further, the light emitting element 10 is mounted on the driver IC 20 by a flip chip method. That is, when the mounting bumps 12 on the lower surface of the light emitting element 10 are bonded to the mounting pads 21 on the upper surface of the driver IC 20, the two are integrated and electrically connected to each other.

Then, as shown in FIG. 2, a sealing resin 50 is deposited on a region excluding the light emitting surface 11 which is the upper surface of the light emitting element 10. In this example, a package is configured in which a region that completely covers the driver IC 20 from the side surface region of the light emitting element 10 is sealed with a sealing resin 50. In this example, the sealing resin 50 is silicone. The resin 50 seals the upper surface of the base 30, but is not deposited on the peripheral region of the upper surface of the base 30. That is, the resin 50 is not applied to the region where the input / output pad 32 is formed. Therefore, the input / output pad 32 is exposed from the resin 50. The light emitting element 10 and the driver IC 20 are sealed with a resin 50 as a sealing material in a state where the light emitting surface 11 of the light emitting element 10 is exposed.

For example, a resin potting method can be employed as the step of sealing the resin 50. The resin potting method is, for example, a 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. Alternatively, a mold frame (not shown) is temporarily placed on the base 30 so as to surround the driver IC 20, a resin having fluidity is filled in the mold frame, and the mold is removed after the resin is cured. May be. Alternatively, a method may be used in which a resin is formed in a predetermined shape in advance, and this resin is adhered so as to cover the driver IC 20 with an adhesive or the like. In any case, the step of sealing the resin may be performed by a method of sealing the driver IC in a liquid-tight or air-tight state with the resin.

Furthermore, the light source module 1 may include an attachment 40. In this example, the attachment 40 is fixed to the upper surface of the heat sink 111. The attachment 40 is formed as a rectangular frame 41 by an insulating material such as resin so as to surround the base 30. The attachment 40 is provided with support pieces 42 at a plurality of locations on the lower edge of the frame 41. The attachment 40 is fixed to the heat sink 111 with screws 43 in the support piece 42. A top plate is formed on the upper edge of the frame 41. An opening window is formed on the top plate so as not to affect the light emitted from the light emitting element 10. In other words, the top plate provided with the opening window formed in the frame body 41 forms the roof plate 44. Further, the attachment 40 has a connector housing 45 integrally formed with the frame body 41 at a part in the circumferential direction of the frame body 41. The connector housing 45 is formed in a rectangular tube shape that opens toward the side of the frame body 41 (leftward in FIG. 2).

The frame body 41 is formed with a plurality of conductive materials such as metal. The conductive material such as metal is formed so as to be integrated with the frame body 41 by, for example, insert molding. A part of the conductive material is configured as a plurality of connector terminals 46, and the other part of the conductive material is configured as a plurality of contact pieces 47. The connector terminal 46 is disposed in the connector housing 45. The connector terminal 46 is electrically connected to an external connector (not shown). Further, the plurality of contact pieces 47 are arranged in the circumferential direction along the inner surface of the flange plate 44, and are configured to be extended so that the tips thereof protrude downward. The contact piece 47 has elasticity. The connector terminal 46 and the contact piece 47 are electrically connected to each other.

When fixing the attachment 40 to the heat sink 111, the contact piece 47 of the attachment 40 contacts the input / output pad 32 of the base 30. At this time, the contact piece 47 is elastically deformed by the elasticity of the contact piece 47 and comes into contact with the input / output pad 32, and the contact piece 47 and the input / output pad 32 are electrically connected to each other. Further, an external connector (not shown) is fitted into the connector housing 45. Thereby, the connector terminal 46 is electrically connected to the external connector. The external connector is electrically connected to the power supply unit 201 and the control unit 210 shown in FIG. When the connector terminal 46 is electrically connected to the external connector, the power source / control system 200 is electrically connected to the light source module 1.

FIG. 4 is a schematic diagram illustrating an example of the circuit configuration of the light emitting element 10 and the circuit configuration of the driver IC 20. A plurality of LEDs are arranged in the light emitting element 10 as described above. The light emitting element 10 is supplied with power from the power supply unit 201 via the mounting bump 12, the mounting pad 21, and the mounting bump 22.
The driver IC 20 is configured as a current driving circuit. The driver IC 20 includes a current mirror circuit including, for example, transistors Tr1 and Tr2. This current mirror circuit is controlled by a control signal output from the control unit 210 via the mounting bump 22. Specifically, the base current of the transistor Tr3 is controlled to turn on / off the operation of the current mirror circuit, and the current of the transistor Tr2 is controlled. As a result, the current supplied to the LED connected to the transistor Tr2 is controlled, and the light emission of each LED is controlled individually or in batches at a predetermined number.

As shown in FIG. 1, when the light source module 1 is fixed to the heat sink 111, the light emitting surface 11 of the light emitting element 10 is directed to the front of the lamp unit 110. Then, the control unit 210 controls the driver IC 20 to control the light emission of the plurality of LEDs disposed on the upper surface of the light emitting element 10. The light emitted from each LED on the upper surface of the light emitting element 10 is projected onto the front area of the automobile by the projection lens 112. Although the detailed description is omitted, since the plurality of LEDs are respectively arranged so as to 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 the required light distribution is achieved. Illumination at is performed.

Then, the imaging camera 211 shown in FIG. 1 detects other vehicles existing in the front area of the automobile, that is, preceding vehicles and oncoming vehicles. The control unit 210 outputs a required control signal to the driver IC 20 based on the detection by the imaging camera 211. The driver IC 20 extinguishes or dims the LED corresponding to the area where the detected other vehicle is present among the LEDs on the upper surface of the light emitting element 10, thereby brightening the other area without dazzling the other vehicle. ADB control to illuminate is executed.

As described above, the light source module 1 according to this embodiment forms a package by sealing the light-emitting element 10 and the driver IC 20 with the resin 50 in an airtight or liquid-tight manner so as not to prevent light emission from the light-emitting element 10. ing. Therefore, the light emitting element 10 and the driver IC 20 can be protected from the severe external environment of the automobile. That is, by sealing the light emitting element 10 and the driver IC 20 to form a package, the LED of the light emitting element 10 and the transistor element of the driver IC 20 are protected from temperature change, humidity change, vibration, impact, and the like. Thereby, stable current control of the light source module 1 can be performed, and suitable ADB control can be realized.

Further, the driver IC 20 and the light emitting element 10 are covered in the surrounding area or the upper area by the frame body 41 and the cover plate 44 of the attachment 40 in a range that does not affect the emission of light from the light emitting element 10. Thereby, the surrounding area or the upper area can be protected from an external impact.

Of the heat generated by the light emission of the light emitting element 10, 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 of the heat generated by the light emission of the light emitting element 10 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 can be obtained. Since the base 30 dissipates heat, thermal reliability in the light emitting element 10 and the driver IC 20 is ensured.

(Embodiment 2)
Next, a light source module 1A according to Embodiment 2 of the present disclosure will be described with reference to the drawings. FIG. 5 is a cross-sectional view of the light source module 1A according to the second embodiment. In the light source module 1A according to the second embodiment, the same or equivalent parts as those of the light source module 1 according to the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.
A base 30A is fixed to the heat sink 111 of the lamp unit. A driver IC 20 is mounted on the base 30A. The light emitting element 10 is mounted on the upper surface of the driver IC 20. Further, the driver IC 20 and the light emitting element 10 are packaged with a sealing resin 50. The attachment 40A is fixed to the side of the heat sink 111 where the base 30A is fixed. Electrical connection to the base 30A is made by contact between the contact piece 47 of the attachment 40A and the input / output pad 32 of the base 30A.

In Embodiment 2, the base 30 </ b> A is formed in a shallow dish container shape having a peripheral wall 34. In other words, the base 30A is formed in a concave shape with the peripheral wall 34 convex in the side view of FIG. A required conductive pattern is formed on the base 30A by a conductive film. With this conductive pattern, a mounting pad 31 and an input / output pad 32 are formed on the base 30A. The mounting pad 31 is disposed on the inner bottom surface of the base 30A. The input / output pad 32 is disposed on the upper surface of the peripheral wall 34. The base 30 </ b> A has a dimension in the height direction of the base 30 </ b> A such that the upper surface of the peripheral wall 34 and the light emitting surface of the light emitting element 10 are substantially equal to each other, The dimension is set to a height that is slightly lower.

As in the first embodiment, the driver IC 20 and the light emitting element 10 are mounted and mounted on the inner bottom surface of the base 30A. The inside including the inner bottom surface of the base 30A is filled with a sealing resin 50. The resin 50 seals the entire driver IC 20 and the peripheral region of the light emitting element 10.

As described above, the light source module 1A of Embodiment 2 can realize the package of the light emitting element 10 and the driver IC 20 by filling the sealing resin 50 inside the container-like base 30A. For this reason, in the second embodiment, the driver IC 20 and the light emitting element 10 can be easily sealed as compared with the sealing step of the resin 50 in the first embodiment. In Embodiment 2, since the resin 50 is filled in the base 30A surrounded by the peripheral wall 34, the resin 50 does not lose its shape due to impact or vibration, and the reliability of the package is improved. Furthermore, in the second embodiment, the input / output pad 32 is formed on the peripheral wall 34, and the resin 50 can be filled in the whole of the container-like concave portion of the base 30A. Therefore, the contact area between the resin 50 and the base 30A is reduced. It can be larger than that in the first mode. For this reason, when part of the heat generated in the light emitting element 10 is transferred to the base 30A via the resin 50, the amount of heat transferred to the base 30A can be made larger than that in the first embodiment, and the heat dissipation effect is further enhanced. be able to.

(Embodiment 3)
Next, a light source module 1B according to Embodiment 3 of the present disclosure will be described with reference to the drawings. FIG. 6 is a cross-sectional view of the light source module 1B according to the third embodiment. The third embodiment corresponds to a modification of the second embodiment. In the light source module 1B according to the third embodiment, the same or equivalent parts as those of the light source module 1A according to the second embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.
In the third embodiment, the driver IC 20 has no mounting bump formed on the lower surface, and the bonding pad 23 is disposed on the periphery of the upper surface. Further, the base 30B has a peripheral wall 34 formed in two stages, a mounting pad 31 is formed on the upper surface of the inner lower peripheral wall 34, and an input / output pad 32 is formed on the upper surface of the outer higher peripheral wall 34. ing.

The driver IC 20 is mounted on the inner bottom surface of the base 30B by adhesion or bonding. The bonding pads 23 of the driver IC 20 and the mounting pads 31 of the base 30B are electrically connected by bonding wires 24. The base 30B is filled with a sealing resin 50 as in the second embodiment. That is, the resin 50 is filled inside the peripheral wall 34. The light emitting element 10, the driver IC 20, and the bonding wire 24 are sealed with a resin 50 filled inside the peripheral wall 34 to form a package.

The connector terminal 46 and the contact piece 47 are formed of a conductive material insert-molded in the frame 41 of the attachment 40B. The attachment 40B is provided with a cover 48 made of a conductive material. The cover 48 covers the cover plate 44. The cover 48 is provided independently of the conductive material forming the contact piece 47. The inner tip of the cover 48 is extended to the vicinity of the periphery of the light emitting element 10. The cover 48 functions as a shield that electromagnetically shields at least the upper region of the driver IC 20. Note that 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.

As described above, in the light source module 1B of the third embodiment, the light emitting element 10, the driver IC 20, and the bonding wire 24 are sealed by the package resin 50. Thereby, the light emitting element 10 and the driver IC 20 can be protected from the external environment, and the reliability of the light source module 1B is improved. In the light source module 1B of 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 electromagnetically shielded by the cover 48. The effect makes it possible to protect from external electromagnetic waves and static electricity. As a result, the electrical reliability of the driver IC 20 can be improved.

As mentioned above, although embodiment of this indication was described, the technical scope of this indication should not be interpreted limitedly by explanation of the above-mentioned embodiment. The above embodiment is merely an example, and it is understood by those skilled in the art that various modifications can be made within the scope of the invention described in the claims.
In the present disclosure, each embodiment described above exemplifies a micro LED as a light emitting element. However, the light emitting element mounted on the driver IC of the light source module of the present disclosure is not limited to the micro LED, and may be an LED array, a semiconductor laser, an organic EL, or the like. Further, the light emitting element and the driver IC in the present disclosure are not limited to one each. The light source module of the present disclosure may include a plurality of light emitting elements and a plurality of driver ICs. Further, the plurality of light emitting elements and the plurality of driver ICs may be configured to be integrally packaged, or may be configured to be individually packaged.

In the present disclosure, 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 above embodiment. For example, a connector may be provided on the base without providing an attachment, and the connector and an external power / control system may be electrically connected.

In the present disclosure, 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 may include not only a circuit for driving a current supplied to the light emitting element but also a part of a control circuit for controlling the power supplied to the light emitting element.

This application is based on Japanese Patent Application No. 2018-39229 filed on March 6, 2018, the contents of which are incorporated herein by reference.

Claims

A chip-like light emitting element;
A driver device for driving the light emitting element,
The light emitting element is integrally mounted on the driver device,
A light source module in which the light emitting element and the driver device are sealed with a sealing material in a state where the light emitting surface of the light emitting element is exposed.
A base on which the driver device is mounted;
The base is attached to a heat sink;
The light source module according to claim 1, wherein the sealing material is disposed on the base.
The driver device is a driver IC in which a circuit for driving the light emitting element is integrated,
The light source module according to claim 1, wherein the light emitting element is mounted on the driver device by a flip chip method.
A base on which the driver device is mounted;
The light source module according to claim 3, wherein the base includes wiring electrically connected to the driver device, and is electrically connected to an external power supply / control system via the wiring.
An attachment electrically connected to the wiring of the base;
The light source module according to claim 4, wherein the attachment includes a connector that is electrically connected to the external power supply / control system.
A base on which the driver device is mounted;
The light source module according to claim 3, wherein the driver device is mounted on the base by a flip chip method.
A base on which the driver device is mounted;
The light source module according to any one of claims 3 to 5, wherein the driver device is mounted on the base by wire bonding.
The light source module according to any one of claims 1 to 7, wherein the sealing material is a resin.