JP2016004850A - On-vehicle laser light source unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an on-vehicle laser light source unit capable of preventing deterioration of a semiconductor chip that emits laser light, and that can be miniaturized.SOLUTION: An on-vehicle laser light source unit 100 is provided with first to third semiconductor chips 20-22 that emit laser light with different wavelengths. Each semiconductor chip 20-22 is mounted as a bare chip on a bottom face 12 of a hollow part 11 of a ceramic package 10. The hollow part 11 of the ceramic package 10 is provided with: first to third wavelength selection devices 30-32 that selectively transmit or reflect light with a predetermined wavelength of respective laser light emitted from the respective semiconductor chips 20-22 to combine the respective laser light; and a collimator lens 40 that makes the laser light combined by the respective wavelength selection devices 30-32 parallel and emits it to the exterior. The hollow part 11 of the ceramic package 10 is sealed with a metal lid 60.

Description

  The present invention relates to an in-vehicle laser light source unit.

  Conventionally, a laser light source unit as an image display device has been proposed in Patent Document 1, for example. Specifically, a semiconductor chip that emits red laser light and a semiconductor chip that emits green laser light are mounted on a case formed of a resin or the like, and are configured to emit blue laser light. A configuration in which a CAN package is fixed to a case has been proposed. The CAN package is disposed in a through hole provided in the wall of the case.

JP 2011-91396 A

  However, in the above-described conventional technology, since the two semiconductor chips and the CAN package are accommodated in one case, the outside air containing moisture in the case via the boundary between the CAN package and the case. Will invade. For this reason, there exists a problem that the humidity in a case will rise and a semiconductor chip will deteriorate. Deterioration of the semiconductor chip is not preferable because it leads to lowering of the brightness of the laser light and non-lighting. Therefore, a structure for sealing the semiconductor chip in the case is desired.

  In an in-vehicle environment where the laser light source unit is mounted on a vehicle and used, the laser light source unit is likely to be exposed to high temperatures. Since the semiconductor chip has low heat resistance, it is necessary to cool the laser light source unit. However, the configuration using the semiconductor laser of the CAN package increases the size of the laser light source unit, increases the cooling capacity of the cooling mechanism, and increases the heat dissipation capacity. There is a problem of increase. Therefore, downsizing of the laser light source unit is desired.

  An object of the present invention is to provide a vehicle-mounted laser light source unit that can prevent deterioration of a semiconductor chip that emits laser light and can be downsized.

  In order to achieve the above object, the invention according to claim 1 is an in-vehicle laser light source unit mounted on a vehicle, and is characterized by the following points.

  That is, a plurality of semiconductor chips (20, 21, 22) that irradiate laser beams having different wavelengths are provided. The ceramic package (10) has a bottomed shape having a hollow portion (11), and a plurality of semiconductor chips (20, 21, 22) are bare-chip mounted on the bottom surface (12) of the hollow portion (11). I have.

  In addition, wavelength selective elements (30, 31) that synthesize laser beams by selectively transmitting or reflecting light of a predetermined wavelength among the laser beams irradiated from the plurality of semiconductor chips (20, 21, 22). 32) and a collimating lens (40) for emitting laser light synthesized by the wavelength selection elements (30, 31, 32) to the outside as parallel light.

  Furthermore, it is equipped with the plate-shaped cover part (60, 61) which seals the hollow part (11) of a ceramic package (10) by being fixed to the opening end (14) of a ceramic package (10). And

  According to this, since each semiconductor chip (20, 21, 22) is sealed in the hollow portion (11) of the ceramic package (10), it is possible to block each semiconductor chip (20, 21, 22) from the outside air. it can. In addition, since the material itself of the ceramic package (10) hardly allows the outside air to pass through the hollow portion (11), the airtightness of the hollow portion (11) can be maintained for a long period of time. Thus, since each semiconductor chip (20, 21, 22) is not influenced by outside air, it is possible to prevent the deterioration of each semiconductor chip (20, 21, 22).

  Furthermore, since all the semiconductor chips (20, 21, 22) are bare-chip mounted on the ceramic package (10) without using the CAN package, the ceramic package (10) can be reduced in size. Thereby, the whole vehicle-mounted laser light source unit can be reduced in size.

  In addition, the code | symbol in the bracket | parenthesis of each means described in this column and the claim shows the correspondence with the specific means as described in embodiment mentioned later.

It is a top view of the vehicle-mounted laser light source unit which concerns on 1st Embodiment of this invention. It is II-II sectional drawing of FIG. It is sectional drawing which showed the mounting structure of the vehicle-mounted laser light source unit. It is a top view of the vehicle-mounted laser light source unit which concerns on 2nd Embodiment of this invention. It is sectional drawing of the vehicle-mounted laser light source unit which concerns on 3rd Embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following embodiments, the same or equivalent parts are denoted by the same reference numerals in the drawings.

(First embodiment)
Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. The laser light source unit according to the present embodiment is mounted on a vehicle and is used as a light source for a laser head-up display or a projector.

  As shown in FIGS. 1 and 2, the in-vehicle laser light source unit 100 includes a ceramic package 10, first to third semiconductor chips 20 to 22, first to third wavelength selection elements 30 to 32, a collimating lens 40, A photodiode 50 and a metal lid 60 are provided.

  The ceramic package 10 is a bottomed shape having a hollow portion 11, that is, a box-shaped case. The ceramic package 10 accommodates the semiconductor chips 20 to 22, the wavelength selection elements 30 to 32, the collimating lens 40, and the photodiode 50 in the hollow portion 11.

  The ceramic package 10 is configured, for example, by laminating and firing a plurality of ceramic substrates. The ceramic package 10 includes a wiring pattern (not shown) provided at the bonding portion of each ceramic substrate, and a conductor part such as a pad or a pin (not shown) provided on the outer wall surface and electrically connected to the wiring pattern. Yes. The semiconductor chips 20 to 22 and the photodiode 50 are electrically connected to the wiring pattern.

  The first to third semiconductor chips 20 to 22 are light sources that irradiate laser beams having different wavelengths. Each semiconductor chip 20 to 22 is bare-chip mounted on the bottom surface 12 of the hollow portion 11 of the ceramic package 10. And each semiconductor chip 20-22 irradiates a laser beam according to the signal input from the outside, respectively.

  The first semiconductor chip 20 is formed so as to emit blue laser light having a specific wavelength. The second semiconductor chip 21 is configured to emit green laser light as laser light having a wavelength different from that of the first semiconductor chip 20. The third semiconductor chip 22 is configured to emit red laser light as laser light having a wavelength different from that of the first semiconductor chip 20 and the second semiconductor chip 21.

  In this embodiment, since each semiconductor chip 20-22 is arrange | positioned in the same row | line | column, there exists a merit that it is easy to carry out a bare chip mounting to the ceramic package 10, irradiating a laser beam. Further, since the laser beams of the respective semiconductor chips 20 to 22 are optical paths reflected by the respective wavelength selection elements 30 to 32, there is an advantage that the characteristics of the respective semiconductor chips 20 to 22 can be easily obtained.

  The first to third wavelength selection elements 30 to 32 synthesize the laser beams by selectively transmitting or reflecting light of a predetermined wavelength among the laser beams irradiated from the semiconductor chips 20 to 22. It is. Each wavelength selection element 30-32 is comprised as a filter which selectively reflects or permeate | transmits a laser beam, for example with the thin film formed in the board | substrate.

  The first wavelength selection element 30 is disposed opposite to the first semiconductor chip 20. The first wavelength selection element 30 reflects the blue laser light emitted from the first semiconductor chip 20 toward the collimating lens 40 side.

  The second wavelength selection element 31 is disposed opposite to the second semiconductor chip 21. The second wavelength selection element 31 transmits the blue laser light from the first wavelength selection element 30 and reflects the green laser light emitted from the second semiconductor chip 21 toward the collimator lens 40 side. As described above, the second wavelength selection element 31 combines the blue and green laser beams.

  The third wavelength selection element 32 is disposed to face the third semiconductor chip 22. The third wavelength selection element 32 transmits the blue and green laser lights from the second wavelength selection element 31 and reflects the red laser light emitted from the third semiconductor chip 22 toward the collimator lens 40 side. . As described above, the third wavelength selection element 32 plays a role of combining blue, green, and red laser beams and guiding them to the collimating lens 40.

  The collimating lens 40 emits the laser light synthesized by the wavelength selection elements 30 to 32 to the outside of the ceramic package 10 as parallel light. The collimating lens 40 is fixed to the inner wall via a low-melting glass (not shown) so as to emit laser light from the through hole 13 provided in the side wall of the ceramic package 10.

  The photodiode 50 is housed in the hollow portion 11 of the ceramic package 10 and detects the state of the laser light by receiving the laser light transmitted or reflected by the third wavelength selection element 32. In the present embodiment, the photodiode 50 is disposed at a position facing the third wavelength selection element 32 on the inner wall of the ceramic package 10. The photodiode 50 is electrically connected to a wiring pattern formed in the ceramic package 10.

  According to such an arrangement, the photodiode 50 receives a slight amount of laser light reflected and transmitted by the third wavelength selection element 32. That is, the photodiode 50 receives all the blue, green, and red laser beams. The photodiode 50 outputs a detection signal corresponding to the intensity of the received laser beam to the outside.

  According to this, it becomes possible to perform feedback control such as color balance for each of the semiconductor chips 20 to 22 in accordance with the detection result of the photodiode 50. Thus, the output adjustment of each semiconductor chip 20-22 can be performed in real time according to the temperature characteristic of a laser beam using the photodiode 50. FIG.

  The metal lid 60 is a plate-like lid component that closes the opening of the ceramic package 10. As shown in FIG. 2, the metal lid 60 seals the hollow portion 11 of the ceramic package 10 by being fixed to the open end 14 of the ceramic package 10. The metal lid 60 is resistance welded to the open end 14 of the ceramic package 10.

  In the present embodiment, the hollow portion 11 is filled with any of nitrogen, oxygen, and vacuum. That is, each semiconductor chip 20-22, each wavelength selection element 30-32, the photodiode 50, and the collimating lens 40 are sealed. Thus, since the hollow part 11 is satisfy | filled with any of nitrogen, oxygen, and a vacuum, each semiconductor chip 20-22 arrange | positioned in the hollow part 11 is made not to receive to the influence of the moisture contained in external air. be able to.

  Further, since the metal lid 60 is made of metal formed of Kovar or the like, it also serves to block light. Therefore, since light does not enter the hollow portion 11 of the ceramic package 10 from the outside by the metal lid 60, it is possible to suppress a decrease in the accuracy of the laser light emitted from the collimating lens 40 to the outside.

  The above is the overall configuration of the in-vehicle laser light source unit 100 according to the present embodiment. The in-vehicle laser light source unit 100 is arranged on the dashboard, ceiling, etc. of the vehicle so as to irradiate image light toward the front window.

  Next, a mounting structure of the in-vehicle laser light source unit 100 will be described. As shown in FIG. 3, the in-vehicle laser light source unit 100 is mounted on one surface 210 of the circuit board 200. The circuit board 200 is a printed board, a ceramic board, a flexible board, or the like. On one surface 210 of the circuit board 200, an IC chip and an electronic component (not shown) for controlling the semiconductor chips 20 to 22 are mounted.

  The Peltier element 300 is mounted on the other surface 220 of the circuit board 200 opposite to the one surface 210. The Peltier element 300 serves to cool the in-vehicle laser light source unit 100. A heat dissipation mechanism 400 is disposed on the opposite side of the Peltier element 300 from the circuit board 200. The heat dissipation mechanism 400 plays a role of cooling the heat generated by the Peltier element 300, and includes, for example, a heat sink, a refrigerant mechanism, an air cooling mechanism, and a water cooling mechanism. As described above, the in-vehicle laser light source unit 100 can be incorporated into the cooling structure.

  As described above, in the present embodiment, the semiconductor chips 20 to 22 are sealed in the hollow portion 11 of the ceramic package 10. Thereby, each semiconductor chip 20-22 can be shielded from outside air. In addition, the material itself of the ceramic package 10 is difficult to pass outside air through the hollow portion 11. Thereby, the airtightness of the hollow part 11 of the ceramic package 10 can be maintained over a long period of time. In particular, when cooling with the Peltier element 300 or the like, the semiconductor chips 20 to 22 are sealed, so that the semiconductor chips 20 to 22 can be prevented from dew condensation.

  In this way, the semiconductor chips 20 to 22 can be prevented from being affected by the outside air due to the airtightness of the ceramic package 10. Therefore, deterioration of each semiconductor chip 20-22 can be prevented.

  Further, the in-vehicle laser light source unit 100 according to the present embodiment accommodates all the semiconductor chips 20 to 22 without using the CAN package. For this reason, the ceramic package 10 can be reduced in size, and the whole vehicle-mounted laser light source unit can be reduced in size. And since the vehicle-mounted laser light source unit 100 is miniaturized, the cooling capacity can be minimized, and the heat dissipation structure can be minimized. That is, the entire system using the in-vehicle laser light source unit 100 can be downsized.

  In addition, regarding the correspondence between the description of the present embodiment and the description of the claims, the metal lid 60 corresponds to a “lid” in the claims.

(Second Embodiment)
In the present embodiment, parts different from the first embodiment will be described. As shown in FIG. 4, the first semiconductor chip 20 is disposed on the optical path connecting the second wavelength selection element 31, the third wavelength selection element 32, and the collimating lens 40. That is, in the present embodiment, the first wavelength selection element 30 is not provided in the configuration of the first embodiment.

  Therefore, the second wavelength selection element 31 transmits the blue laser light emitted from the first semiconductor chip 20 and reflects the green laser light emitted from the second semiconductor chip 21. The third wavelength selection element 32 transmits the blue and green laser light from the second wavelength selection element 31 and reflects the red laser light emitted from the third semiconductor chip 22 to collimate the laser light. Guide to lens 40.

  As described above, the on-vehicle laser light source unit 100 may be configured not to include the first wavelength selection element 30. In this configuration, the space for arranging the first wavelength selection element 30 does not have to be taken into consideration, so that the ceramic package 10 can be further reduced in size.

  Regarding the correspondence between the description of the present embodiment and the description of the claims, the second wavelength selection element 31 corresponds to the “first wavelength selection element” in the claims, and the third wavelength selection element 32. Corresponds to the “second wavelength selection element” in the claims.

(Third embodiment)
In the present embodiment, parts different from the first and second embodiments will be described. As shown in FIG. 5, the in-vehicle laser light source unit 100 includes a transparent glass lid 61 that seals the hollow portion 11 of the ceramic package 10. The glass lid 61 is fixed to the open end 14 of the ceramic package 10 with a low melting point glass or the like. FIG. 5 is a cross-sectional view corresponding to the II-II cross section of FIG.

  Thereby, since the hollow part 11 of the ceramic package 10 can be visually recognized through the glass lid 61 from the outside, it is easy to confirm whether each of the semiconductor chips 20 to 22 is normally irradiating laser light. Can be provided.

  In addition, regarding the correspondence between the description of the present embodiment and the description of the claims, the glass lid 61 corresponds to the “lid portion” of the claims.

(Other embodiments)
The configuration of the in-vehicle laser light source unit 100 shown in each of the above embodiments is merely an example, and is not limited to the configuration described above, and may be another configuration that can realize the present invention. For example, the arrangement position of the photodiode 50 is not limited to the position shown in the above embodiments, and may be arranged at other positions. The number of photodiodes 50 is not limited to one, and may be provided corresponding to each of the semiconductor chips 20-22. On the other hand, the photodiode 50 is not an essential component, and may be configured without the photodiode 50.

  Further, the arrangement positions of the semiconductor chips 20 to 22 are not limited to the arrangement positions shown in the above embodiments. For example, the arrangement positions of the first semiconductor chip 20 and the third semiconductor chip 22 may be reversed. In this case, the arrangement positions of the wavelength selection elements 30 to 32 may also correspond to the semiconductor chip. Further, the laser light is not limited to red, green, and blue, and other colors may be used.

  The configuration for cooling the in-vehicle laser light source unit 100 is not limited to the configuration shown in FIG. For example, the Peltier element 300 may be sandwiched between the in-vehicle laser light source unit 100 and the circuit board 200.

DESCRIPTION OF SYMBOLS 10 Ceramic package 11 Hollow part 12 Bottom face 14 Open end 20-22 Semiconductor chip 30-32 Wavelength selection element 40 Collimating lens 60 Metal lid (lid part)

Claims (7)

An in-vehicle laser light source unit mounted on a vehicle,
A plurality of semiconductor chips (20, 21, 22) for irradiating laser beams of different wavelengths;
A ceramic package (10) having a bottomed shape having a hollow portion (11), wherein the plurality of semiconductor chips (20, 21, 22) are bare-chip mounted on a bottom surface (12) of the hollow portion (11); ,
Wavelength selection elements (30, 31, 22) that combine laser beams by selectively transmitting or reflecting light of a predetermined wavelength among the laser beams irradiated from the plurality of semiconductor chips (20, 21, 22). 32)
A collimating lens (40) for emitting the laser beam synthesized by the wavelength selection element (30, 31, 32) to the outside as parallel light;
Plate-like lid portions (60, 61) for sealing the hollow portion (11) of the ceramic package (10) by being fixed to the open end (14) of the ceramic package (10);
An in-vehicle laser light source unit comprising: As the plurality of semiconductor chips, a first semiconductor chip (20) that irradiates a laser beam having a specific wavelength and a second semiconductor chip (21) that irradiates a laser beam having a wavelength different from that of the first semiconductor chip (20). And a third semiconductor chip (22) for irradiating a laser beam having a wavelength different from that of the first semiconductor chip (20) and the second semiconductor chip (21),
The wavelength selection element is:
A first wavelength selection element (30) for reflecting the laser light emitted from the first semiconductor chip (20);
A second wavelength selection element (31) that transmits the laser light from the first wavelength selection element (30) and reflects the laser light emitted from the second semiconductor chip (21);
A third wavelength that transmits the laser light from the second wavelength selection element (31) and reflects the laser light emitted from the third semiconductor chip (22) to guide the laser light to the collimating lens (40); A selection element (32);
The in-vehicle laser light source unit according to claim 1, comprising: As the plurality of semiconductor chips, a first semiconductor chip (20) that irradiates a laser beam having a specific wavelength and a second semiconductor chip (21) that irradiates a laser beam having a wavelength different from that of the first semiconductor chip (20). And a third semiconductor chip (22) for irradiating a laser beam having a wavelength different from that of the first semiconductor chip (20) and the second semiconductor chip (21),
The wavelength selection element is:
A first wavelength selection element (31) that transmits the laser light emitted from the first semiconductor chip (20) and reflects the laser light emitted from the second semiconductor chip (21);
A second wavelength that transmits the laser light from the first wavelength selection element (31) and reflects the laser light emitted from the third semiconductor chip (22) to guide the laser light to the collimating lens (40). A selection element (32);
The in-vehicle laser light source unit according to claim 1, comprising:   A photodiode that detects the state of the laser beam by receiving the laser beam that is housed in the hollow portion (11) of the ceramic package (10) and that is transmitted or reflected by the wavelength selection element (30 to 32). The in-vehicle laser light source unit according to any one of claims 1 to 3, further comprising (50).   The in-vehicle laser light source unit according to any one of claims 1 to 4, wherein the lid is a metal lid (60) made of metal.   The in-vehicle laser light source unit according to any one of claims 1 to 4, wherein the lid portion is a glass lid (61).   The in-vehicle laser light source unit according to any one of claims 1 to 6, wherein the hollow portion (11) is filled with any one of nitrogen, oxygen, and vacuum.

Images