JP6890248B2 - Cooling device and projection type image display device - Google Patents

Description

The present disclosure relates to a cooling device for cooling heat-generating components used inside a projection type image display device.

A projection type image display device using a digital micromirror device (hereinafter referred to as "DMD") as an optical modulation element is commercially available. With the high performance of projection type image display devices, high resolution and high brightness have been required. In order to increase the brightness, the DMD is irradiated with strong illumination light, and at this time, the temperature of the DMD rises due to the absorption of the light of the DMD. Therefore, the DMD is provided with a structure for cooling it.

Patent Document 1 discloses a cooling device that cools an image display element. This cooling device is composed of a heat sink, a ventilation duct, and a fan, thereby cooling the image display element.

Japanese Unexamined Patent Publication No. 2000-338603

The present disclosure provides a highly efficient cooling device that cools the heat generated by parts due to high brightness.

The cooling device in the present disclosure is coupled to a heat conductive base portion that is thermally connected to a heat generating portion, a heat pipe housed in the base portion, and a base portion so as to cover the heat pipe. It is provided with a fin portion having a plurality of fins.

The cooling device in the present disclosure is effective in improving the cooling efficiency of reducing the temperature of heat-generating components.

The figure which shows the structure of the projection type image display device which mounted the cooling device in Embodiment 1. The figure which shows the phosphor wheel used in the projection type image display device in Embodiment 1. External perspective view of the heat sink according to the first embodiment The perspective view which shows the disassembled state of the heat sink in Embodiment 1. The perspective view which shows the structure of the base part of the heat sink in Embodiment 1. The perspective view which shows the disassembled state of the base part of the heat sink and the heat pipe in Embodiment 1. The perspective view which shows the disassembled state of the base part of the heat sink and the heat pipe in Embodiment 2. The perspective view which shows the structure of the base part of the heat sink in Embodiment 2. Perspective view showing the configuration of the base portion of the heat sink in another embodiment.

Hereinafter, embodiments will be described in detail with reference to the drawings as appropriate. However, more detailed explanation than necessary may be omitted. For example, detailed explanations of already well-known matters and duplicate explanations for substantially the same configuration may be omitted. This is to avoid unnecessary redundancy of the following description and to facilitate the understanding of those skilled in the art.

It should be noted that the accompanying drawings and the following description are provided for those skilled in the art to fully understand the present disclosure, and are not intended to limit the subject matter described in the claims.

(Embodiment 1)
Hereinafter, the first embodiment will be described with reference to FIGS. 1 to 6.

[1-1. Configuration description]
[1-1-1. Overall configuration]
FIG. 1 is a diagram for explaining a configuration of an optical system of a projection type image display device 1 equipped with the cooling device of the present disclosure. For convenience of the following description, FIGS. 1 to 6 assume the XYZ Cartesian coordinate system shown in the figure.

First, the illumination optical system 20 of the projection type image display device 1 will be described. The laser light source 201, which is an excitation light source, is a blue semiconductor laser, and is composed of a plurality of semiconductor lasers in order to realize a high-luminance illumination device. In FIG. 1, five blue semiconductor lasers are shown juxtaposed as an example, but a plurality of blue semiconductor lasers are arranged on a plane in a matrix. The laser light, which is the excitation light emitted from each of the laser light sources 201, is collimated by the corresponding collimating lens 202. The light emitted from the collimated lens 202 is substantially parallel light. The total luminous flux of this parallel light is condensed by the lens 203, passes through the diffuser plate 204, and then is converted into substantially parallel light again by the lens 205. The laser luminous flux converted to substantially parallel light by the lens 205 is incident on the dichroic mirror 206 arranged at approximately 45 degrees with respect to the optical axis.

The diffusion plate 204 is a glass flat plate, and a diffusion surface having fine irregularities is formed on one surface. Further, the dichroic mirror 206 has a characteristic of reflecting light in the wavelength range of the blue semiconductor laser and transmitting light in other wavelength ranges.

The laser beam incident on the dichroic mirror 206 in the −Y direction in FIG. 1 is reflected by the dichroic mirror 206 and emitted in the −X direction in FIG. After that, the laser beam is focused by the lens 207 and the lens 208 to excite the phosphor formed in the phosphor wheel device 10.

As shown in the side view (a) of FIG. 2, the phosphor wheel device 10 includes a motor 101 and a rotating base material 102 made of a disk-shaped plate body that is rotationally driven around the rotation axis of the motor 101. Will be done.

As shown in the front view (b) of FIG. 2, the rotating base material 102 is red with a predetermined width W inside and outside the circumference on the circumference separated by a distance R1 from the center A of the rotation axis of the phosphor wheel. The phosphor portion 103, the green phosphor portion 104, and the opening 105 are formed.

When the laser light from the laser light source 201 is focused on the red phosphor unit 103 of the phosphor wheel device 10, the red phosphor unit 103 is excited and emits red light. Further, when the laser light from the laser light source 201 is focused on the green phosphor portion 104 of the phosphor wheel device 10, the green phosphor portion 104 is excited and emits green light. Further, the laser light from the laser light source 201 that concentrates on the opening 105 of the phosphor wheel device 10 passes through the phosphor wheel device 10.

Returning to FIG. 1, the red light and the green light obtained by the phosphor wheel device 10 are emitted from the phosphor wheel device 10 in the + X direction. The fluorescent light emitted in the −X direction by the red phosphor unit 103 and the green phosphor unit 104 is reflected by the rotating base material 102 and emitted in the + X direction. These red and green lights are parallelized by the lenses 208 and 207, pass through the dichroic mirror 206, are condensed by the condenser lens 217, and are incident on the rod integrator 218.

On the other hand, the blue light of the blue semiconductor laser that has passed through the opening 105 travels along the path of the lens 209, the lens 210, the mirror 211, the lens 212, the mirror 213, the lens 214, the mirror 215, and the lens 216, and is reflected by the dichroic mirror 206. , It is condensed by the condenser lens 217 and incident on the rod integrator 218. The lenses 212, 214, and 216 function as relay lenses.

The light emitted from the rod integrator 218 enters the TIR (total internal reflection) prism 235 composed of a pair of prisms of the first prism 233 and the second prism 234 through the lens 230, the lens 231 and the lens 232, and the light is emitted. In DMD (Digital Prismor Device) 236, which is a modulation element, incident light is modulated by a video signal and emitted as video light P. The lens 230 and 231 have a relay lens, and the lens 232 has a function of forming an image of light on the exit surface of the rod integrator 218 on the DMD 236.

The light emitted from the DMD 236 is incident on the projection lens 237, and the light emitted from the projection lens 237 is magnified and projected onto the screen as image light P. The projection lens 237 is an example of a projection optical system.

In the DMD 236, a part of the light incident on the DMD 236 changes to heat and generates heat. The DMD 236 is an example of a heat generating portion in a projection type image display device. The heat sink 300, which is thermally connected to the DMD 236 via the connecting member 330, cools the DMD 236. The heat sink 300 is an example of a cooling device, and although details will be described later, a base portion 310 for burying the heat pipes by integrally accommodating the plurality of heat pipes and a plurality of fins 322 on the base plate 321 are provided. It is provided with a fin portion 320 provided. In this embodiment, a cooling fan 390 is further provided. The heat generated by the DMD 236 is thermally conducted to the heat sink 300, and the fan 390 blows air to the heat sink 300 to dissipate the heat of the heat sink. The base portion 310 and the fin portion 320 constituting the heat sink 300 are made of aluminum. Further, the connecting member 330 integrally provided on the base portion 310 is also made of aluminum.

[1-1-2. Heat sink configuration]
3 is a perspective view of the heat sink 300 of FIG. 1, FIG. 4 is a perspective view showing a state in which the heat sink 300 is disassembled into a base portion 310 and a fin portion 320, and FIG. 5 is an enlarged perspective view of the base portion 310, FIG. Is a perspective view showing a state in which the heat pipes 340 and 350 are removed from the base portion 310.

The heat sink 300 is composed of a base portion 310, a fin portion 320, and a pair of heat pipes 340 and 350. The fin portion 320 is configured by planting a plurality of fins 322 made of thin aluminum plates at regular intervals on an aluminum base plate 321. The fin portion 320 can be formed by integrally molding the base plate 321 and the fin 322 by die-casting using a material such as aluminum.

As shown in FIGS. 4 to 6, the heat pipes 340 and 350 have two extending portions extending in the same direction (X direction) from both ends of the bottom portion and the bottom portion, and have an opening on the side facing the bottom portion. It forms a character shape. The two stretches have approximately the same length and are longer than the bottom. The cross section of the plane perpendicular to the direction in which the heat pipe extends is configured to have a substantially rectangular shape.

As shown in FIG. 6, the base portion 310 is provided with a pair of accommodating groove portions 360, 370 in which heat pipes 340 and 350 are embedded on one side of an aluminum plate body. The accommodating groove portions 360 and 370 are formed in a shape that allows surface contact with each other as much as possible when the heat pipes 340 and 350 are fitted. In the present embodiment, aluminum, which is a material having excellent thermal conductivity, is used for the base portion 310, but the base portion 310 is not limited to this, and may be made of, for example, copper. The solder alloy can be poured into the gap between the accommodating groove portions 360 and 370 and the heat pipes 340 and 350 to further strengthen the thermal connection between the accommodating groove portions 360 and 370 and the heat pipes 340 and 350.

The heat pipe 340 is fitted into the accommodating groove portion 360 of the base portion 310, and the heat pipe 350 is fitted and installed in the accommodating groove portion 370 of the base portion 310, whereby the heat pipes 340 and 350 are arranged alternately. Will be done. In other words, the accommodating groove portions 360 and 370 are formed so that the heat pipes 340 and 350 are juxtaposed in a staggered state. That is, as shown in FIGS. 4 to 6, the heat pipe 340 has an opening in the −X direction, the heat pipe 350 has an opening in the + X direction, and the opening directions (extending directions) are different from each other by 180 °. Arranged like this. Further, the pair of heat pipes 340 and 350 are juxtaposed in the Z direction so that the extending portions on the same side of each other are adjacent to each other.

As shown in FIG. 3, a connecting member 330 is provided on the surface of the base portion 310 opposite to the side on which the fin portion 320 is arranged (the side on which the heat pipes 340 and 350 are arranged). The connecting member 330 is mechanically and thermally connected to the DMD 236 and is integrally provided with the base portion 310 by aluminum. The position where the connecting member 330 is arranged is shown by the broken line in FIG. 5, and is arranged at a position where the heat pipe 340 and the heat pipe 350 are adjacent to each other and straddling the heat pipe 340 and the heat pipe 350. That is, the connecting member 330 is viewed from the normal direction of the surface on which the heat pipes 340 and 350 are juxtaposed (that is, the Y direction in which the connecting member 330 is arranged with respect to the base portion 310). It is arranged at a position where it overlaps with the extension portions adjacent to each other.

The surface of the base portion 310 on the accommodating groove forming side and the base plate 321 are joined and fixed so as to cover the heat pipe with silicon grease interposed therebetween. By this joining, the base plate 321 is thermally connected not only to the base portion but also to the heat pipe so as to abut. In this case, as shown in FIG. 4, the fin portion 320 is arranged with respect to the base portion 310 so that the direction in which the fins 322 are arranged is the same as the extending direction (X direction) of the heat pipes 340 and 350. However, it is not limited to this. The fin portion 320 may be arranged with respect to the base portion 310 so that the direction in which the fins 322 are lined up is the direction (Z direction) perpendicular to the extending direction of the heat pipes 340 and 350.

[1-2. Heat sink operation]
The illumination light focused by the lens 232 enters the TIR prism 235 and irradiates the DMD 236. The illumination light absorbed without being reflected by the DMD 236 changes to heat and conducts heat to the vicinity of the center of the base portion 310 of the heat sink 300 via the connecting member 330.

The heat conducted near the center of the base portion 310 is diffused by the heat pipes 340 and 350. The diffused heat is conducted to the base plate 321 of the fin portion 320, then is conducted to the fin 322, and is dissipated by the fan 390. The heat pipes 340 and 350 contain a working liquid inside a copper case, and when the working liquid receives heat, the heat pipes circulate and transfer heat in the heat pipe. The amount of heat transfer varies depending on the positional relationship between the part that dissipates heat and the direction of gravity. In the present embodiment, the heat pipes 340 and 350 have a U shape and are arranged alternately in order to suppress a difference in the amount of heat transfer depending on the installation direction of the heat sink (heat pipe).

Since the heat pipes 340 and 350 are arranged so as to be in close contact with the surface of the base portion 310 forming the accommodating groove portions 360 and 370, the heat absorbed by the heat pipes 340 and 350 is applied to the entire base portion 310. It diffuses and is efficiently dissipated by the fin portion 320.

[1-3. Effect, etc.]
As described above, in the present embodiment, the heat generated by the illumination light irradiating the DMD can be effectively diffused by the heat pipe, and the diffused heat can be electrically conducted to the fins, so that the heat is effectively dissipated. be able to. Further, even when the heat sink 300 is installed in the installation direction, for example, the Z axis is in the direction of gravity, high cooling capacity can be maintained and heat can be effectively dissipated.

(Embodiment 2)
Hereinafter, the second embodiment will be described with reference to FIGS. 7 and 8. In the second embodiment, the configuration of the base portion is different from that of the first embodiment, and the other configurations and operations are the same as those of the first embodiment. Therefore, the duplicate description thereof will be omitted. Further, also in the following description, it is assumed that the XYZ Cartesian coordinate system shown in FIGS. 7 and 8 is adopted.

FIG. 7 is a perspective view showing the base portion 380 used in the heat sink of the present embodiment together with the heat pipes 340 and 350, and FIG. 8 is a perspective view showing a state in which the heat pipes 340 and 350 are arranged on the base portion. is there.

The base portion 380 has a dish shape, and a pair of heat pipes 340 and 350 are arranged in close proximity to and alternately arranged in the accommodating recess 381. Although not shown in FIGS. 7 and 8, a connecting member 330 is provided on the opposite side of the accommodating recess 381 of the base portion 380, as in the case of the heat sink 300 shown in FIG. The base portion 380 and the connecting member 330 are made of aluminum. When the heat pipes 340 and 350 are arranged in the accommodation recess 381, the molten solder alloy is poured into the accommodation recess, and the space of the accommodation recess 381 is filled with the solder alloy to bury the heat pipes 340 and 350. After that, the storage recess 381 is joined so as to be covered with the base plate 321 of the fin portion 320. Here, the solder alloy is an example of a heat conductive material.

As a result, the heat generated by the DMD 236 is efficiently dissipated from the fin portion 320 as in the first embodiment.

(Other embodiments)
As described above, the first embodiment and the second embodiment have been described as examples of the techniques disclosed in the present application. However, the technique in the present disclosure is not limited to this, and can be applied to embodiments in which changes, replacements, additions, omissions, etc. are made. It is also possible to combine the components described in the first and second embodiments to form a new embodiment. Therefore, other embodiments will be illustrated below.

The arrangement of the pair of heat pipes is not limited to the examples shown in the first and second embodiments, and can be arranged as shown in FIG. 9, for example. That is, the heat pipes 341 and 351 may be arranged on the base portion 311 with one of the extending portions inserted into the openings of each other. In this case, in the heat pipes 341 and 351, the lengths of the two stretched portions extending from both sides of the bottom portion may be different as shown in FIG. 9, or may be configured to have the same length. By arranging the same heat pipes 341 and 351 in a staggered manner in this way, the heat sink exhibits a good heat dissipation effect regardless of the installation direction, as in the first and second embodiments.

In each embodiment, DMD has been described as an example of the heat generating portion. The heat generating portion is not limited to DMD. The back surface of the semiconductor laser case may be used as the heat generating portion.

Since the above-described embodiment is for exemplifying the technique in the present disclosure, various changes, replacements, additions, omissions, etc. can be made within the scope of claims or the equivalent scope thereof.

The present disclosure is applicable to a projection type image display device such as a projector.

1 Projection type image display device 20 Illumination optical system 201 Laser light source 202 Collimating lens 233 First prism 234 Second prism 235 TIR prism 236 DMD
300 Heat sink 310,311 Base part 320 Fin part 321 Base plate 322 Fin 330 Connection member 340,341,350,351 Heat pipe 360,370 Storage groove 380 Base part 381 Storage recess 390 Fan

Claims (4)

A plurality of thermally conductive bases that are thermally connected to the heat generating portion, heat pipes embedded in the bases, and the bases that are coupled to the bases so as to cover the heat pipes. With a fin part with fins,
A pair of the heat pipes are provided, each heat pipe has a U-shape, and the heat pipes are alternately arranged in the storage recesses provided in the base portion, and the space of the storage recess is made of a heat conductive material. A cooling device in which a certain solder alloy is filled and the heat pipe is embedded. When a connecting member is further provided on the side of the base portion opposite to the side to which the fin portion is connected, and the connecting member is viewed in a direction in which the connecting member is arranged with respect to the base portion. The cooling device according to claim 1, wherein the connecting member is arranged at a position where it overlaps with both of the pair of heat pipes. The cooling device according to claim 1, further comprising a fan that blows air to the fin portion. An illumination optical system including a light source, an optical modulation element that modulates the illumination light emitted from the illumination optical system with an image signal and emits an image light, and an enlarged projection of the image light emitted from the light modulation element. A projection type image display device comprising a projection optical system and a cooling device according to any one of claims 1 to 3, which is thermally connected to the light modulation element.

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