Light source module

Abstract

To provide a technique capable of reducing the volume of a moisture-proof space for moisture-proof sealing of a light source module.SOLUTION: The light source module 100 includes a first laser 117 configured to emit red light, a second laser 118 configured to emit green light, a third laser 119 configured to emit blue light, an electronic cooling module 530 configured to adjust a temperature of the first laser 117, a first case 410 configured to accommodate the first laser 117, and a second case 420 configured to accommodate the second laser 118 and the third laser 119.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to an improved technology for a light source module. [Background technology]

[0002] 2. Description of the Related Art A light source module is used in various image display devices. 2. Description of Related Art A conventional technique for such a light source module is disclosed in Patent Document 1, for example.

[0003] The technology disclosed in Patent Document 1 configures a laser light source unit with a light source module (light source unit) that combines and emits laser light and an optical system (projection unit) that projects the laser light emitted from the light source module. Image display devices, such as color projectors, use three lasers (red, blue, and green). Due to the temperature-dependent light emission characteristics of these lasers, forced cooling using an electronic cooling module such as a Peltier element may be required. When forced cooling is performed, the cooling unit is cooled below the dew point temperature, and moisture-proof sealing is performed to trap dry air and prevent condensation from forming on the lasers. In the technology disclosed in Patent Document 1, the entire light source module, including the three lasers (red, blue, and green), is housed in a single sealed housing. Therefore, the entire light source module is moisture-proof sealed. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6606633 Summary of the Invention [Problem to be solved by the invention]

[0005] However, with the technology disclosed in Patent Document 1, as the size of the three lasers increases, the moisture-proof space inside the housing also inevitably becomes larger. If the moisture-proof space is large, fluctuations in the internal pressure of the moisture-proof space due to temperature changes will apply a large force to the sealing member, and the amount of water vapor remaining in the sealed space will increase. For this reason, it is necessary to reduce the sealed space.

[0006] The present invention has been made to solve the above problems, and an object of the present invention is to provide a technology that can reduce the volume of the moisture-proof space that seals the light source module against moisture. [Means for solving the problem]

[0007] The light source module in the first aspect includes a first laser configured to emit red light, a second laser configured to emit green light, a third laser configured to emit blue light, an electronic cooling module that adjusts the temperature of the first laser, a first case that houses the first laser, and a second case that houses the second laser and the third laser.

[0008] In a light source module according to a second aspect which may be dependent on the first aspect, the second case has a moisture permeable portion which allows water vapor to pass through.

[0009] A light source module according to a third aspect which may be dependent on the first or second aspect, further comprising: the first case has a transmission portion that transmits the red light and can seal the inside of the first case, The transmission portion is arranged to transmit the red light and allow it to enter the second case.

[0010] A fourth aspect of the light source module may be dependent on the third aspect, the second case includes a dichroic mirror that combines the green light, the blue light, and the red light; the dichroic mirror is disposed on an optical path of the red light incident from the transmission portion and is tilted with respect to an incident direction of the red light, a direction in which the red light is reflected by the dichroic mirror and travels is defined as a first direction, and a direction opposite to the first direction is defined as a second direction; The transmitting portion is inclined relative to the dichroic mirror so that the end in the first direction is spaced farther away from the dichroic mirror than the end in the second direction.

[0011] A light source module according to a fifth aspect which may be dependent on any of the first to fourth aspects, further comprising: a first heat sink that dissipates heat from the electronic cooling module, and a second heat sink that dissipates heat from the second laser and the third laser; The first heat sink and the second heat sink are arranged with a gap between them.

[0012] A light source module according to a sixth aspect which may be dependent on the fifth aspect, further comprising: further comprising an air-cooling fan that draws in air so that the air flows through the second heat sink and then the first heat sink; The cooling fan is provided on the end surface of the first heat sink opposite to the second heat sink. [Effects of the Invention]

[0013] According to the present invention, the volume of the moisture-proof space that seals the light source module in a moisture-proof manner can be reduced. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1A is an external view of an image display device including a light source module according to an embodiment, and FIG. 1B is a circuit diagram of the image display device shown in FIG. 1A. [Figure 2] 1B is a cross-sectional view of the light source module shown in FIG. 1A. [Figure 3] FIG. 3 is an enlarged view of part 3 of FIG. 2. DETAILED DESCRIPTION OF THE INVENTION

[0015] The present invention will be described below with reference to the accompanying drawings. The best mode described below is used to facilitate understanding of the present invention. Therefore, those skilled in the art should be aware that the present invention is not unduly limited by the embodiment described below.

[0016] 1A and 1B show an example of the appearance of an image display device 10 and an example of the internal configuration of a light source unit 100 and a projection unit 300. In the example of FIGS. 1A and 1B, the image display device 10 is an in-vehicle projection display system (in-vehicle projector) mounted on a vehicle (not shown). However, the image display device 10 of the present invention is not limited to an in-vehicle projection display system mounted on a vehicle (not shown).

[0017] In recent years, image display devices (vehicle-mounted projection display systems) have been required to have higher brightness in order to improve visibility. However, in order to make the light source shine brighter, it is necessary to efficiently dissipate the heat generated by the light source, and the size of heat sinks and other devices used for heat dissipation tends to increase. As a result, image display devices have become larger, and it is possible that they will no longer be able to be installed in the limited space of a vehicle or the like.

[0018] Therefore, in the present invention, the light source unit 100 and the projection unit 300 are separated and a separate image display device 10 (vehicle-mounted projection display system 10) is constructed by utilizing optical transmission technology using an optical fiber cable 220. Hereinafter, the light source unit 100 may be referred to as the "light source module 100." The optical fiber cable 220 may be simply referred to as the "optical fiber 220."

[0019] By separating the light source unit 100 and the projection unit 300, the light source unit 100, which dissipates a large amount of heat, can be installed in any available space in a vehicle, etc., while the projection unit 300, which forms the projected image, can be separated from the heat source and installed freely in an appropriate location, making it easier to install the image display device 10 in a vehicle.

[0020] On the other hand, after the light source unit 100 and the projection unit 300 are installed in an empty space in a vehicle or the like, it is necessary to connect the light source unit 100 and the projection unit 300 with the communication cable 210 and the optical fiber 220. After this work, it is necessary to determine whether the image display device 10 operates normally, and if an abnormal state is detected, it is necessary to take appropriate measures such as stopping the optical output and notifying the abnormality. However, the amount of light transmitted through the optical fiber 220 may vary greatly depending on the wiring condition of the optical fiber 220, the environmental temperature, etc., and under such circumstances, it is not easy to determine whether the state is normal or abnormal based only on the light receiving intensity of the light receiving unit 324 provided on the projection unit 300 side.

[0021] Therefore, in this embodiment, a light receiving unit 123 is also provided on the light source unit 100 side, and information on the actually measured received light intensity obtained from this light receiving unit 123 and information on the actually measured received light intensity obtained from the light receiving unit 324 on the projection unit side are obtained, and by using each piece of information to perform an abnormality determination process in a predetermined procedure, it becomes possible to detect abnormalities in the projection display system 10 caused by the wiring status of the optical fiber 220, the ambient temperature, etc.

[0022] A specific description will be given below with reference to the drawings.

[0023] 1A, image display device 10 has light source unit 100 and projection unit 300 arranged separately, and light source unit 100 and projection unit 300 are electrically connected via communication cable 210, and light for forming a projection image output by light source unit 100 is supplied to projection unit 300 via optical fiber 220, and a projection image is formed by projection unit 300. Note that communication cable 210 can be used to transmit power, control signals, video signals, etc.

[0024] The light source unit 100 has a control board 102, an integrated circuit device 103 including a microcontroller 110 (MCU 110: see FIG. 1B) as a first control unit mounted on the control board 102, and a plurality of mirrors 120-122 as optical elements. On the other hand, the projection unit 300 has a projection aperture (exit aperture) 323 and the like that projects (emits) display light for an image.

[0025] As shown in FIG. 1B, the light source unit 100 includes an MCU 110 as a first control unit, a serializer 112 (parallel / serial converter), a deserializer 114 (parallel / serial converter), an optical element driving unit 116 (LC driver), a plurality of optical elements 117-119 with different light colors (here, laser diodes corresponding to the colors R (red), G (green), and B (blue)), a plurality of mirrors 120-122, a first light receiving unit 123 (here, a first photodiode PD1 is used) that detects the light intensity of light for forming a projection image of each color output from the light source unit 125, an optical output interface 124, and a power circuit 130 (power supply circuit).

[0026] The MCU 110 is an integrated circuit device that integrates a processor that functions as a main CPU (host CPU) with peripheral circuits such as memory.

[0027] The MCU 110 is provided with a first light intensity measuring unit 111 that measures light intensity based on the actual measured values ​​(pd1(R'' / G'' / B'')) of light of each color of red (R), green (G), and blue (B) sent from the first light receiving unit (PD1) 123, and an abnormality determination unit 113.

[0028] An optical element section 125 is configured by a plurality of optical elements 117 to 119 that emit light of different colors, a plurality of mirrors 120 to 122, a first light receiving section (first photodiode PD1) 123, and an optical output interface .

[0029] The serializer 112 and the deserializer 114 form a first serial interface unit SIF1.

[0030] The projection unit 300 has a deserializer (serial / parallel converter) 312, a display controller (display control device) 313 as a second control unit, a serializer (parallel / serial converter) 314, an optical input interface 320, an optical modulation device (here, a DMD (digital mirror device) is used) 322, a second light receiving unit (here, a second photodiode PD2 is used) 324 that detects the light intensity of each color of light for forming a projection image sent via the optical fiber 220, and a power circuit (power supply circuit) 325.

[0031] The display controller 313 is a dedicated integrated circuit device that includes a sub-CPU (not shown) and performs display control in place of the MCU 110.

[0032] The display controller 313 is provided with a second light intensity measuring unit 315 that measures light intensity based on the actual measured values ​​of light of each color R, G, and B (pd2(R'' / G'' / B'')) sent from the second light receiving unit (PD2) 324.

[0033] The deserializer 312 and the serializer 314 form a second serial interface unit SIF2.

[0034] The optical modulation device 322 includes a main body 319 incorporating an optical modulation element, an input terminal 321 of the optical modulation device 322 to which video bitstream data VBSD supplied from the display controller 313 is input, and a projection port 323 for projecting display light for an image.

[0035] The optical input interface 320 receives light for forming a projection image transmitted from the light source unit 100 via the optical fiber 220, and supplies the received light (light of each color R, G, B) to the main body unit 319 of the optical modulation device 322.

[0036] Next, the contents of communication of video signals and control signals via the first serial interface unit SIF1 and the second serial interface unit SIF2 will be described.

[0037] The serial communication signals transmitted and received between the first serial interface unit SIF1 and the second serial interface unit SIF2 include, for example, a serial video signal (LVDS VideoS) transmitted from the light source unit 100 to the projection unit 300 using the LVDS (Low Voltage Differential Signal) transmission method, a light emission enable signal (LDE: specifically, LEDR / G / B LD Enable for each color) which is a signal that enables the light elements 117 to 119 to emit light and is transmitted from the light source unit 100 to the projection unit 300, and various communication signals (Communication S1, Communication S2).

[0038] Next, an example of various communication signals will be described. For example, a vehicle-side controller 90 mounted on a vehicle (not shown) can transmit various request commands C1 based on user settings to the MCU 110 of the light source unit 100.

[0039] Possible request commands include, for example, request commands to change the display brightness, change the color balance, change the image size, change the image position, correct projection distortion, turn the display on / off, and the like.

[0040] The MCU 110 sends the received request command as a communication signal C2 to the serializer 112, and the serializer 112 performs parallel / serial conversion on the received communication signal C2 to generate a communication signal Communication S1 and transmits this communication signal Communication S1 to the projection unit 300 via the communication cable 210. The deserializer 312 of the projection unit 300 performs serial / parallel conversion on the received communication signal Communication S1 to generate a communication signal C3 and sends this communication signal C3 to the display controller (second control unit) 313.

[0041] The display controller 313 performs processing in response to various requests from the MCU 110 of the light source unit 100, and generates a signal C4 indicating the result of the processing (for example, a signal indicating that the processing was successful, or a signal indicating a parameter value obtained as a result of the processing) and sends it to the serializer 314. The serializer 314 performs parallel / serial conversion on the communication signal C4 to generate a communication signal Communication S2, and transmits this communication signal Communication S2 to the light source unit 100 via the communication cable 210. The deserializer 114 of the light source unit 100 performs serial / parallel conversion on the received communication signal Communication S2 to generate a communication signal C5, and sends this communication signal C5 to the MCU 110.

[0042] In this way, the MCU 110 and the display controller 313 can transmit and receive various signals via the first and second serial interface units SF1 and SF2.

[0043] Next, transmission of the video signal will be described. The vehicle-side controller 90 transmits the video signal VideoS to the serializer 112 of the light source unit 100. The serializer 112 generates an LDVS-type video signal LDVS VideoS based on the received video signal VideoS and transmits it to the projection unit 300 via the communication cable 210. The deserializer 312 of the projection unit 300 converts the received LDVS-type video signal LDVS VideoS into a parallel-format digital video signal VD and sends the digital video signal VD to the display controller 313.

[0044] Next, the flow of signals related to the abnormality determination process will be described. The display controller 313 can transmit the actual measurement value (pd2) of the second light intensity measurement unit 315 to the light source unit 100 as light intensity information LI.

[0045] The light intensity information LI sent from the display controller 313 is converted from parallel to serial by the serializer 314 and transmitted to the light source unit 100 as light intensity information LI (Light Intesity) in serial format.

[0046] The deserializer 114 of the light source unit 100 performs serial / parallel conversion on the received serial-format light intensity information LI and transmits it as a communication signal C5 to the MCU 110 (more specifically, the abnormality determination unit 113), and in parallel with this, supplies the light intensity information LI to the optical element driving unit 116.

[0047] The abnormality determination unit 113, which receives the light intensity information LI, executes a predetermined process using the actual measurement value (pd2) at the second light receiving unit 324 (PD2) of the projection unit 300, and, if necessary, generates a light source drive value control signal PCR and sends it to the light element drive unit 110, thereby appropriately controlling the light emission intensity of the light elements 117 to 119 of each color.

[0048] Furthermore, the optical element driver 116 finely adjusts the light emission intensity of the optical elements 117-119 of each color so that the variation in the transmitted light intensity information LI (actual measurement value (pd2) at the second light receiving unit (PD2)) within a predetermined period falls within a predetermined level. This allows APC (Automatic Power Control) to be performed, which stabilizes the light output of the multiple optical elements 117-119 that emit different colors of light.

[0049] Furthermore, power supply PS is supplied from the vehicle-side controller 90 to the power circuit 130 of the light source unit 100. The power circuit 130 supplies a power supply voltage to the power circuit 325 of the projection unit 300 via the communication cable 210. The power circuit 325 supplies the power supply voltage to each unit within the projection unit 300.

[0050] As described above, each of the optical elements 117 to 119 is configured by a laser diode (also called a laser). Hereinafter, the optical element 117 configured to emit red light (R) may be referred to as the "first laser 117," the optical element 118 configured to emit green light (G) may be referred to as the "second laser 118," and the optical element 119 configured to emit blue light (B) may be referred to as the "third laser 119." All of the lasers 117 to 119 emit light in the same direction.

[0051] Furthermore, among the multiple mirrors 120 to 122, mirror 120 that reflects red light (R) emitted from first laser 117 may be referred to as the "first mirror 120," mirror 121 that reflects green light (G) emitted from second laser 118 may be referred to as the "second mirror 121," and mirror 122 that reflects blue light (B) emitted from third laser 119 may be referred to as the "third mirror 122."

[0052] Next, with reference to FIGS. 1A, 2 and 3, the housing structure and cooling structure for the plurality of lasers 117 to 119 will be described.

[0053] 2, second mirror 121 reflects the green light emitted from second laser 118. This second mirror 121 is disposed on the optical path of the green light incident from second laser 118, and is tilted with respect to the incident direction D1 of the green light.

[0054] Third mirror 122 transmits the green light emitted from second laser 118 and reflected by second mirror 121, and reflects the blue light emitted from third laser 119. Third mirror 122 is disposed on the optical path of the blue light incident from third laser 119, and is tilted with respect to the incident direction D2 of the blue light.

[0055] The first mirror 120 transmits the green light emitted from the second laser 118 and the blue light emitted from the third laser 119, and reflects the red light emitted from the first laser 117. In other words, the first mirror 120 is configured as a dichroic mirror that combines the green light, the blue light, and the red light. The first mirror 120 may also be referred to as the "dichroic mirror 120" as appropriate. The dichroic mirror 120 is disposed on the optical path of the red light incident from the first laser 117, is tilted with respect to the incident direction D3 of the red light, and faces the light receiving surface 124a of the light output interface 124.

[0056] All of the mirrors 120-122 and the optical output interface 124 are located on the same optical axis (on the same line). The second mirror 121 and the third mirror 122 are tilted in the same direction as the first mirror 120. Therefore, the optical output interface 124 can receive the light emitted from each of the lasers 117-119.

[0057] Here, the direction R1 in which the red light emitted from the first laser 117 travels after being reflected by the first mirror 120 (dichroic mirror 120) is referred to as the "first direction R1." The direction R2 opposite to the first direction R1 is referred to as the "second direction R2."

[0058] The second mirror 121 that reflects green light, the third mirror 122 that reflects blue light, and the first mirror 120 that reflects red light are arranged in this order in the first direction R1, i.e., toward the light receiving surface 124a of the light output interface 124. Correspondingly, the second laser 118 that emits green light, the third laser 119 that emits blue light, and the first laser 117 that emits red light are also arranged in this order in the first direction R1.

[0059] The lasers 117-119, the mirrors 120-122, and the optical output interface 124 are housed in a case 400. This case 400 is composed of a first case 410 that houses only the first laser 117, and a second case 420 that houses the second and third lasers 118, 119. The second case 420 further houses all of the mirrors 120-122 and the optical output interface 124. An internal space 421 (second housing space 421) of this second case 420 is sealed to prevent dust.

[0060] Generally, the first laser 117 dissipates more heat than the second and third lasers 118 and 119. For this reason, the temperature of the first laser 117 is adjusted by an electronic cooling module 530. This electronic cooling module 530 is preferably configured by a Peltier element 531 (Peltier module 531) that is small and lightweight and allows for easy temperature control of small components such as lasers.

[0061] When the temperature of the first laser 117 is adjusted, if the area of ​​the first laser 117 that should be cooled is exposed to humid air, condensation may occur, which may hinder normal operation of the first laser 117. In particular, water vapor molecules are smaller than dust. To address this, the internal space 411 (first storage space 411) of the first case 410 is moisture-proof sealed. By providing a moisture-proof seal, higher airtightness (hermetic sealing) can be ensured compared to a dust-proof seal. Dry air is trapped in the moisture-proof sealed first storage space 411.

[0062] The first storage space 411 is highly airtight due to the moisture-proof sealing. Moreover, the first case 410 is extremely small because it only needs to store the first laser 117. Therefore, the volume Vm of the first storage space 411 (moisture-proof space 411) that is to be moisture-proof sealed can be made as small as possible. This is extremely advantageous in terms of providing moisture-proof sealing to the first storage space 411.

[0063] As shown in FIG. 1A, the control board 102 and the integrated circuit device 103 are provided in a dustproof sealed state on the side of the case 400, but may be housed in the second housing space 421 of the second case 420.

[0064] The structure of the case 400 will now be described in detail.

[0065] First, the second case 420 will be described. 2, second case 420 is a rectangular box that has a dustproof sealed structure and is made up of a frame-shaped case main body 422 that penetrates from top to bottom, a flat bottom plate 423 (first plate 423) that closes one opening of case main body 422, and a flat top plate 424 (second plate 424) that closes the other opening of case main body 422. Optical output interface 124 is attached to the side of case main body 422.

[0066] A first heat dissipation plate 510 and a second heat dissipation plate 520 are attached to a top plate 424 of the second case 420 .

[0067] A portion of the first heat dissipation plate 510 protrudes from the top plate 424 into the first storage space 411, and the first laser 117 is provided in close proximity to the first heat dissipation plate 510. An electronic cooling module 530 and a sealing plate 540 are stacked in this order and fixed to the surface of the first heat dissipation plate 510 opposite the first laser 117. One end surface 541 of the sealing plate 540 is a flat exposed surface exposed from the top plate 424. At least one of the first heat dissipation plate 510, the electronic cooling module 530, and the sealing plate 540 is moisture-proof sealed to the top plate 424. One example of the moisture-proof sealing configuration is a sealing structure using a sealing member (not shown) such as a highly airtight adhesive or packing.

[0068] A portion of the second heat dissipation plate 520 protrudes from the top plate 424 into the second storage space 421, and the second and third lasers 118, 119 are individually and closely provided thereon. A surface 521 (one end surface 521) of the second heat dissipation plate 520 opposite the second and third lasers 118, 119 is a flat exposed surface exposed from the top plate 424.

[0069] In this way, all the lasers 117 to 119 are arranged in a row on the inner surface of the top panel 424 (the surface on the second storage space 421 side).

[0070] Furthermore, second case 420 has moisture-permeable portion 550 that can transmit water vapor generated in second storage space 421 but can prevent moisture from passing through. This moisture-permeable portion 550 has both waterproof properties that prevent moisture from entering from the outside and moisture permeability that allows moisture from second storage space 421 to pass through, and is made of, for example, a moisture-permeable waterproof sheet. Water vapor within second storage space 421 is dissipated to the outside from moisture-permeable portion 550.

[0071] Because water vapor in second storage space 421 tends to rise, in order to increase the moisture permeability of moisture permeable portion 550, it is preferable to provide moisture permeable portion 550 at the upper end of second case 420, for example, on top plate 424. Furthermore, in order to prevent moisture from entering second storage space 421 from the outside through moisture permeable portion 550, it is preferable to arrange moisture permeable portion 550 at the upper end of second case 420 and below first heat sink 560, which will be described later.

[0072] Furthermore, the light source module 100 has a first heat sink 560 that dissipates heat from the first laser 117, a second heat sink 570 that dissipates heat from the second laser 118 and the third laser 119, and an air-cooling fan 580 that dissipates heat from the first and second heat sinks 570 into the atmosphere.

[0073] The first heat sink 560 and the second heat sink 570 are arranged along the surface of the top plate 424 with a gap Cr between them, and are attached to the second case 420. Because there is a gap Cr between the first heat sink 560 and the second heat sink 570, an air layer exists in this gap Cr. The existence of this air layer makes it possible to prevent heat transfer between the first and second heat sinks 560, 570 as much as possible.

[0074] The first heat sink 560 is overlaid on the entire surface of the sealing plate 540 in a heat-transferable manner. Therefore, heat from the electronic cooling module 530 can be dissipated to the first heat sink 560. The second heat sink 570 is overlaid on the entire surface of the second heat dissipation plate 520 in a heat-transferable manner. Therefore, heat from the second laser 118 and the third laser 119 can be dissipated to the second heat sink 570. The first and second heat sinks 560, 570 are configured by, for example, a plate fin heat sink, a pin fin heat sink, or a corrugated fin heat sink.

[0075] An air intake 572 is provided on an end surface 571 of the second heat sink 570 opposite to the first heat sink 560. The air intake 572 is provided with a dustproof filter 573 such as a wire mesh.

[0076] The air-cooling fan 580 is provided on the end face 561 of the first heat sink 560 opposite to the second heat sink 570, and sucks in outside air Ar (air Ar) taken in from the intake port 572 so that it flows through the second heat sink 570 and then the first heat sink 560.

[0077] Outside air Ar (air Ar) drawn in by air-cooling fan 580 passes through dustproof filter 573 and enters second heat sink 570 from intake port 572. Heat generated by second and third lasers 118, 119 is transferred from second heat dissipation plate 520 to second heat sink 570 and dissipated by heat exchange with air Ar. Air Ar that has passed through second heat sink 570 enters first heat sink 560.

[0078] The heat generated by the first laser 117 is transmitted from the first heat dissipation plate 510 to the electronic cooling module 530 and dissipated, and then transmitted from the electronic cooling module 530 through the sealing plate 540 to the first heat sink 560, where it is further dissipated by heat exchange with the air Ar. The air Ar that has passed through the first heat sink 560 is dissipated into the atmosphere by the air-cooling fan 580.

[0079] Next, the first case 410 will be described. 3, it is preferable for the first case 410 to be housed in the second case 420 that includes the first laser 117 in order to achieve a compact and integrated case 400. For this purpose, the first case 410 is configured to cover the first laser 117 arranged on the top plate 424 of the second case 420 in a moisture-proof sealed manner.

[0080] More specifically, first case 410 is a rectangular box, and is provided integrally with top plate 424 of second case 420. That is, only top end 412 of first case 410 is open. This open top end 412 is closed and moisture-proof sealed by top plate 424. One example of the moisture-proof sealing configuration is a sealing structure using a sealing member (not shown) such as a highly airtight adhesive or packing. Bottom plate 413 of first case 410 is a flat plate-shaped portion that faces bottom plate 423 of second case 420 and reflective surface 120a of first mirror 120.

[0081] First case 410 includes a transmitting section 590 to transmit red light emitted from first laser 117 housed in first housing space 411 through first case 410 to first mirror 120. This transmitting section 590 is arranged to allow the red light emitted from first laser 117 to pass through first case 410 and enter second case 420 (second housing space 421). More specifically, this transmitting section 590 is a flat member such as a transparent glass plate provided on bottom plate 413 of first case 410, and is moisture-proof sealed to first case 410. One example of the moisture-proof sealing configuration is a sealing structure using a sealing member (not shown) such as a highly airtight adhesive or packing. As is clear from the above description, first case 410 is entirely moisture-proof sealed.

[0082] The first mirror 120 is disposed on the optical path of the red light incident from the first laser 117 after passing through the transmitting portion 590, and is tilted with respect to the incident direction D3 of the red light. A transmitting surface 591 of the transmitting portion 590 is a flat surface facing the reflecting surface 120a of the first mirror 120. The transmitting surface 591 of the transmitting portion 590 is tilted with respect to the reflecting surface 120a of the first mirror 120 so that an end 592 in the first direction R1 is spaced farther apart from the end 593 in the second direction R2. In other words, the transmitting surface 591 of the transmitting portion 590 widens with respect to the reflecting surface 120a of the first mirror 120 as it approaches the light receiving surface 124a of the light output interface 124 (as it approaches the first direction R1). The opening angle of the transmitting surface 591 of the transmitting portion 590 with respect to the reflecting surface 120a of the first mirror 120 is θ.

[0083] The above explanation can be summarized as follows.

[0084] As shown in FIG. 2, the light source module 100 includes a first laser 117 configured to emit red light, a second laser 118 configured to emit green light, a third laser 119 configured to emit blue light, an electronic cooling module 530 that adjusts the temperature of the first laser 117, a first case 410 that houses the first laser 117, and a second case 420 that houses the second laser 118 and the third laser 119.

[0085] In this way, only the first laser 117, which is forcibly cooled by the electronic cooling module 530, is housed in the first case 410. The first case 410 is compact because it houses only the first laser 117, separate from the second laser 118 and the third laser 119. The volume Vm of the moisture-proof space 411 (first housing space 411) that is sealed against moisture can be made as small as possible, making it easy to prevent moisture. Because the volume Vm of the moisture-proof space 411 is small, the force applied to the sealing member (not shown) due to internal pressure fluctuations caused by temperature changes is small, and the amount of water vapor remaining in the moisture-proof space 411 can be reduced.

[0086] Furthermore, as shown in FIG. 2, second case 420 has moisture permeable portion 550 that is capable of transmitting water vapor.

[0087] Therefore, water vapor generated in internal space 421 (second storage space 421) of second case 420 can be dissipated to the outside through moisture permeable portion 550. The amount of water vapor remaining in second storage space 421 can be reduced.

[0088] 3, first case 410 has a transmission section 590 that transmits red light and can seal the inside of first case 410 (first storage space 411). This transmission section 590 is arranged to transmit red light and allow it to enter second case 420 (second storage space 421).

[0089] First case 410 is sealed by transmitting portion 590 that transmits red light. Therefore, interior 411 (moisture-proof space 411, first storage space 411) of first case 410 can be made dustproof and moisture-proof. Even though first case 410 has a moisture-proof sealed configuration, red light emitted from first laser 117 stored in interior 411 of first case 410 can be efficiently incident on reflecting surface 120a of first mirror 120.

[0090] 3, the second case 420 further includes a dichroic mirror 120 (first mirror 120) that combines the green light, the blue light, and the red light. The dichroic mirror 120 is disposed on the optical path of the red light incident from the transmission portion 590 and is tilted with respect to the incident direction D3 of the red light. The direction R1 in which the red light travels after being reflected by the dichroic mirror 120 is defined as a first direction R1. The direction R2 opposite to the first direction R1 is defined as a second direction R2. The transmission portion 590 is tilted relative to the dichroic mirror 120 so that an end 592 in the first direction R1 is farther away from the dichroic mirror 120 than an end 593 in the second direction R2.

[0091] By using a simple configuration in which the transmitting portion 590 is tilted relative to the dichroic mirror 120, stray light caused by reflection of red light on the dichroic mirror 120 can be prevented as much as possible, and as a result, only light with a regular optical path can be incident on the optical output interface 124 as much as possible.

[0092] 2, the light source module 100 further includes a first heat sink 560 that dissipates heat from the electronic cooling module 530, and a second heat sink 570 that dissipates heat from the second laser 118 and the third laser 119. The first heat sink 560 and the second heat sink 570 are arranged with a gap Cr between them.

[0093] Since there is a gap Cr between the first heat sink 560 and the second heat sink 570, heat transfer therebetween can be prevented, and as a result, each of the lasers 117 to 119 can be cooled efficiently.

[0094] 2, the light source module 100 further includes an air-cooling fan 580 that draws in air Ar so that it flows through the second heat sink 570 and then the first heat sink 560. The air-cooling fan 580 is provided on an end surface 561 of the first heat sink 560 opposite to the second heat sink 570.

[0095] The air-cooling fan 580 flows air Ar through the first and second heat sinks 560 and 570, thereby forcibly and efficiently cooling each of the lasers 117 to 119. In particular, the relatively large amount of heat generated from the first laser 117 can be forcibly and efficiently cooled by the electronic cooling module 530, the first heat sink 560, and the air-cooling fan 580. Moreover, the second and third lasers 118 and 119, which generate less heat, can be air-cooled first by the second heat sink 570 and the air-cooling fan 580, and then the first laser 117, which generates more heat, can be air-cooled by the first heat sink 560 and the air-cooling fan 580. As a result, all of the lasers 117 to 119 can be cooled even more efficiently.

[0096] It should be noted that the present invention is not limited to the examples provided that the functions and effects of the present invention are achieved. [Industrial Applicability]

[0097] The light source module 100 of the present invention is suitable for use in a projection display system mounted on a vehicle. [Explanation of symbols]

[0098] 10 Image display device 100 Light Source Module 117 First Laser 118 Second Laser 119 Third Laser 120 Dichroic mirror (first mirror) 400 cases 410 Case 1 411 Internal space of the first case (first storage space, moisture-proof space) 420 Case 2 421 Second case internal space (second storage space) 530 Electronic Cooling Module 550 Breathable part 560 1st heat sink 561 End face opposite to the second heat sink 570 Second Heat Sink 580 air cooling fan 590 Transparent part 592 End of the first direction 593 End of the second direction Ar: Outside air Cr void D3 Incident direction of red light R1 1st direction R2 2nd direction Vm Volume of the first storage space (moisture-proof space)

Claims

1. a first laser configured to emit red light; a second laser configured to emit green light; a third laser configured to emit blue light; and a thermoelectric cooling module for adjusting the temperature of the first laser; a first case that houses the first laser; a second case that houses the second laser and the third laser; A light source module comprising:

2. The light source module according to claim 1 , wherein the second case has a moisture-permeable portion that allows water vapor to pass through.

3. the first case has a transmission portion that transmits the red light and can seal the inside of the first case, The light source module according to claim 1 , wherein the transmission portion is arranged to transmit the red light and allow the red light to enter the second case.

4. the second case includes a dichroic mirror that combines the green light, the blue light, and the red light; the dichroic mirror is disposed on an optical path of the red light incident from the transmission portion and is tilted with respect to an incident direction of the red light, a direction in which the red light is reflected by the dichroic mirror and travels is defined as a first direction, and a direction opposite to the first direction is defined as a second direction; The light source module according to claim 3 , wherein the transmissive portion is inclined with respect to the dichroic mirror so that an end in the first direction is spaced farther away from the dichroic mirror than an end in the second direction.

5. a first heat sink that dissipates heat from the electronic cooling module, and a second heat sink that dissipates heat from the second laser and the third laser; The light source module according to claim 1 , wherein the first heat sink and the second heat sink are arranged with a gap therebetween.

6. an air-cooling fan that draws in air so that the air flows through the second heat sink and then the first heat sink; The light source module according to claim 5 , wherein the cooling fan is provided on an end surface of the first heat sink opposite to the second heat sink.

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