JP5175458B2 - Liquid crystal panel unit and projection display device - Google Patents

Description

  The present invention relates to a liquid crystal panel unit and a projection display device, and more particularly to a liquid crystal panel and a cooling structure in the vicinity thereof.

  A projection display device using a liquid crystal panel as a light valve enlarges and projects an image formed by the liquid crystal panel. Specifically, the light incident on the liquid crystal panel is modulated for each pixel by the liquid crystal driven according to the video signal. The modulated light (image light) is projected onto a projection surface such as a screen via an optical system. Here, a part of the light incident on the liquid crystal panel causes a temperature rise of the liquid crystal panel. On the other hand, when the liquid crystal panel exceeds the allowable temperature, the operation becomes unstable or the life is shortened. Therefore, it is necessary to forcibly cool the liquid crystal panel. In particular, in recent years, as a result of promoting the miniaturization and high brightness of the projection display device, the heat density in the device has increased, and it is necessary to cool the liquid crystal panel efficiently.

Therefore, conventionally, the liquid crystal panel has been cooled by a forced air cooling method in which cooling air generated by an air cooling fan is supplied to the liquid crystal panel. For example, it has been common to arrange the outlet of the air duct near the liquid crystal panel unit and supply cooling air to the unit (particularly, the liquid crystal panel). In order to enhance the cooling effect, a technique has also been proposed in which a heat sink is provided on the liquid crystal panel and the generated heat is diffused into the heat sink. For example, Patent Document 1 discloses a heat conductive coupling member in which a light incident end face of a light modulation device (corresponding to the liquid crystal panel) is fixed to a first transparent heat dissipation plate, and a first transparent heat dissipation substrate is disposed on both sides thereof. The projector is fixed to a prism or a second transparent heat radiation plate fixed to the prism, and an air path is formed between the light modulator and the prism or the second transparent heat radiation plate. Is described. According to Patent Document 1, in the projector described above, the light modulation device is cooled by the air passing through the air path, and the heat of the light modulation device is conducted through the first transparent heat radiating plate and the heat conductive coupling member. It is said that the cooling efficiency is improved because the heat is radiated to the prism.
JP 2002-244214 A (page 4 [0026] to [0027], FIG. 5)

However, the structure around the liquid crystal panel disclosed in Patent Document 1 has the following problems.
(1) After the heat of the liquid crystal panel is diffused to the first transparent heat radiating plate, it is conducted to the prism by heat conduction through the heat conductive coupling member. However, the thermally conductive coupling member disclosed or suggested in Patent Document 1 is formed by joining the end faces of two thermally conductive coupling members. That is, there are a total of three members on the heat conduction path from the liquid crystal panel to the prism, that is, the first transparent heat radiating plate and the two heat conductive coupling members. Furthermore, when a 2nd transparent heat sink is arrange | positioned, a total of four members exist. Therefore, the heat conduction path from the liquid crystal panel to the prism is long, and the heat conduction efficiency is not good. In addition, since the plurality of members existing on the heat conduction path are discontinuous with each other, the heat conduction efficiency is further reduced. In short, even if the heat of the liquid crystal panel is diffused to the first transparent heat radiating plate, there is a possibility that a sufficient cooling effect cannot be obtained due to poor heat conduction efficiency thereafter.
(2) Also, since the liquid crystal panel and the prism are fixed, the degree of freedom in aligning and aligning the optical axes of both is greatly limited. In this regard, in Patent Document 1, one thermally conductive coupling member is fixed to the liquid crystal panel side, the other thermally conductive coupling member is fixed to the prism side, and the tip inclined surfaces of both coupling members are slid together. Thus, it is described that the optical axes of the liquid crystal panel and the prism are aligned. However, even if the tip inclined surfaces of the coupling member are slid relative to each other, only one-direction optical axis alignment can be realized. At least, it is impossible to align the prism with the prism by rotating the liquid crystal panel around the optical axis.

  An object of the present invention is to provide a liquid crystal panel unit having a structure capable of efficiently dissipating heat of a liquid crystal panel without impairing the degree of freedom of optical axis alignment and alignment, and a projection display device including the same And to provide.

One of the liquid crystal panel units according to the present invention includes a metal case including a front plate on which an incident window for receiving light is formed, and a rear plate on which an emission window for emitting light is formed, and the case. A liquid crystal panel housed in the body and illuminated by light incident from the incident window , a first glass substrate that is a light incident surface of the liquid crystal panel, and a second glass that is a light emitting surface of the liquid crystal panel Between the glass prayer, a liquid crystal panel provided with at least a liquid crystal layer, a transparent electrode and an alignment film, and between the front plate and the first glass substrate of the liquid crystal panel, and the liquid crystal panel is disposed on the optical path of light incident on the first and a larger transparent thermal diffusion plate than the outer diameter of the glass substrate, the first glass substrate of the liquid crystal panel, the entire surface thereof The heat diffusion plate is in contact with the light exit surface of the heat diffusion plate. Of the light incident surface, the area around the region where light is incident, all are in contact with the front plate, the surface area and volume of the heat diffusion plate is greater than the surface area and volume of the first glass substrate.

Another one of the liquid crystal panel unit of the present invention is a metal housing comprising a front plate on which an entrance window for light incidence is formed, and a back plate on which an exit window for light exit is formed, A liquid crystal panel housed in the casing and illuminated by light incident from the incident window , the first glass substrate being a light incident surface of the liquid crystal panel, and a first light emitting surface of the liquid crystal panel A liquid crystal panel provided with at least a liquid crystal layer, a transparent electrode and an alignment film between the two glass substrates, and between the back plate and the second glass substrate of the liquid crystal panel, and is disposed on the optical path of the light that will be emitted from the liquid crystal panel, and a said second larger translucent than the outer diameter of the glass substrate of the heat diffusion plate, the second glass substrate of the liquid crystal panel, The entire surface is in contact with the light incident surface of the thermal diffusion plate, Of the light emitting surface of the diffusing plate, the area around the area where light is emitted, all are in contact with the back plate, than the surface area and volume of the surface area and volume is the second glass substrate of the thermal diffusion plate Is also big .

Another one of the liquid crystal panel unit of the present invention is a metal housing comprising a front plate on which an entrance window for light incidence is formed, and a back plate on which an exit window for light exit is formed, A liquid crystal panel housed in the casing and illuminated by light incident from the incident window , the first glass substrate being a light incident surface of the liquid crystal panel, and a first light emitting surface of the liquid crystal panel A liquid crystal panel provided with at least a liquid crystal layer, a transparent electrode and an alignment film between the two glass substrates, and between the front plate and the first glass substrate of the liquid crystal panel, and The liquid crystal panel is disposed on the optical path of the light incident on the liquid crystal panel and is between the front plate and the heat diffusion plate, and a light transmissive heat diffusion plate larger than the outer diameter of the first glass substrate. And a Peltier element arranged avoiding the optical path of light incident on the And, the first glass substrate of the liquid crystal panel, the entire surface in contact with the light emitting surface of the heat diffusion plate, the light incident surface of the heat diffusion plate, the area around the region where light is incident , All of which are in contact with the heat absorbing surface of the Peltier element, the waste heat surface of the Peltier element is in contact with the front plate, and the surface area and volume of the heat diffusion plate are the surface area of the first glass substrate and Greater than volume .

Another one of the liquid crystal panel unit of the present invention is a metal housing comprising a front plate on which an entrance window for light incidence is formed, and a back plate on which an exit window for light exit is formed, A liquid crystal panel housed in the casing and illuminated by light incident from the incident window , the first glass substrate being a light incident surface of the liquid crystal panel, and a first light emitting surface of the liquid crystal panel A liquid crystal panel provided with at least a liquid crystal layer, a transparent electrode and an alignment film between the two glass substrates, and between the back plate and the second glass substrate of the liquid crystal panel, and The liquid crystal is disposed on the optical path of the light emitted from the liquid crystal panel, and has a translucent heat diffusion plate larger than the outer diameter of the second glass substrate, and between the back plate and the heat diffusion plate. Peltier arranged avoiding the optical path of light emitted from the panel And a child, the second glass substrate of the liquid crystal panel, the entire surface in contact with the light incident surface of the heat diffusion plate, the light emitting surface of the thermal diffusion plate, a region where light is emitted The entire surrounding area is in contact with the heat absorbing surface of the Peltier element, the waste heat surface of the Peltier element is in contact with the back plate, and the surface area and volume of the heat diffusion plate are the second glass. It is larger than the surface area and volume of the substrate .

  In another one of the liquid crystal panel units of the present invention, the light incident surface of the heat diffusing plate and the heat absorbing surface of the Peltier element are in contact with each other through a heat conductive sheet. In another liquid crystal panel unit of the present invention, the waste heat surface of the Peltier element and the front plate are in contact with each other through a heat conductive sheet.

  In another one of the liquid crystal panel units of the present invention, the light emitting surface of the heat diffusing plate and the heat absorbing surface of the Peltier element are in contact with each other through a heat conductive sheet. In another liquid crystal panel unit of the present invention, the waste heat surface of the Peltier element and the back plate are in contact with each other through a heat conductive sheet.

  The projection display device of the present invention is a projection display device that combines light modulated by a plurality of liquid crystal panel units with a prism, and projects the combined light via a projection lens. It is one of the liquid crystal panel units of the present invention.

  According to the present invention, a liquid crystal panel unit having a structure capable of efficiently dissipating heat of a liquid crystal panel without impairing the degree of freedom of optical axis alignment and alignment, and a projection display device including the same Is realized.

(Embodiment 1)
Hereinafter, an example of an embodiment of a projection display device of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic plan view showing the internal structure of the projection display apparatus of this example. In the case of the projection display device of this example, the constituent elements are accommodated in the outer case 1 that is divided into two parts. First, the arrangement state of main components in the outer case 1 will be outlined. Here, for convenience of explanation, the internal space of the exterior case 1 shown in FIG. 1 is divided into four in the vertical and horizontal directions, the upper right area on the paper is the first area, the upper left area is the second area, and the lower left area is the third area. The lower right area is defined as the fourth area.

  A power supply unit 10 is mainly disposed in the first area of the outer case 1. On the other hand, the optical engine 20 is mainly arranged in the second area to the fourth area. More specifically, the light source lamp 21 is disposed in the fourth area, and the projection lens 22 is disposed in the second area. The light emitted from the light source lamp 21 travels counterclockwise in the order of the fourth area, the third area, and the second area, and is emitted from the projection lens 22. In addition, an intake port (not shown) and intake fans (sirocco fans) 23 and 24 for taking outside air from the intake port are arranged in the second and third areas, respectively, and an exhaust port ( (Not shown) and an exhaust fan (axial fan) 25 for exhausting the air in the outer case 1 to the outside are arranged. The outside air introduced from each intake port by the intake fans 23 and 24 cools a predetermined object to be cooled while passing through a predetermined path in the exterior case 1, and is then exhausted from the exhaust port to the outside by the exhaust fan 25. The However, only the main components arranged in each area are outlined here. Elements other than the above elements may be arranged in each area, and an element is arranged across multiple areas. Sometimes it is done.

  FIG. 2 is a schematic diagram of the optical engine 20 provided in the projection display device of this example. The optical engine 20 includes an illumination optical system 31 including the above-described light source lamp 21 and an integrator optical system 30 that uniformizes the luminance distribution of light (illumination light) emitted from the light source lamp 21. In addition, a color separation optical system 40 that separates light emitted from the illumination optical system 31 into red, green, and blue color lights is provided. Further, three liquid crystal panel units 50R, 50G, and 50B prepared for each color light separated by the color separation optical system 40 and a cross dichroic prism that combines light modulated by the liquid crystal panel units 50R, 50G, and 50B ( XDP) 70 and a projection lens 22 for projecting light synthesized by XDP 70.

  The light source lamp 21 constituting the illumination optical system 31 is a high-pressure discharge lamp such as an ultra-high pressure mercury lamp, a xenon lamp, or a metal halide lamp. A reflector 32 is disposed around the light source lamp 21. The light emitted from the light source lamp 21 is reflected by the reflector 32 and enters the pair of lens arrays 33a and 33b, so that the luminance distribution is made uniform. Specifically, the front lens array 33a divides incident light to form a large number of secondary light source images. The formed secondary light source image is superimposed on the liquid crystal panel by the lens array 33b and the field lens 34 in the subsequent stage. A polarization conversion element 35 is disposed between the lens array 33b and the field lens 34, and the polarization direction of light incident on the field lens 34 is unified (in this example, it is unified to S-polarized light). .

  The color separation optical system 40 includes a blue reflection dichroic mirror 41, a green reflection dichroic mirror 42, and a reflection mirror 43. The light emitted from the integrator optical system 30 first enters the blue reflecting dichroic mirror 41. Of the light incident on the blue reflecting dichroic mirror 41, the blue light is reflected by the mirror 41, then deflected by the reflecting mirror 44 and incident on the liquid crystal panel unit 50B.

  On the other hand, of the green light and the red light transmitted through the blue reflecting dichroic mirror 41, the green light is reflected by the green reflecting dichroic mirror 42 disposed at the subsequent stage of the blue reflecting dichroic mirror 41 and enters the liquid crystal panel unit 50G. .

  The red light transmitted through the green reflecting dichroic mirror 42 is guided to the reflecting mirror 43 by the relay optical system arranged at the subsequent stage of the green reflecting dichroic mirror 42, is reflected by the mirror 43, and enters the liquid crystal panel unit 50R. The relay optical system is composed of two relay lenses 45 and 46 and one reflection mirror 47. In addition, condensing lenses 48R, 48G, and 48B are arranged in front of the respective liquid crystal panel units 50R, 50G, and 50B, and each color light is collimated by the respective condensing lenses 48R, 48G, and 48B. The light enters the corresponding liquid crystal panel units 50R, 50G, and 50B.

  Next, the structure of the liquid crystal panel units 50R, 50G, and 50B, which is a feature of the present invention, will be described. However, since the structures of the units 50R, 50G, and 50B are common, the structure will be described by taking the liquid crystal panel unit 50B as an example. 3 is an external perspective view of the liquid crystal panel unit 50B, FIG. 4 is an exploded perspective view thereof, and FIG. 5 is a sectional view thereof.

  As shown in FIG. 4, the liquid crystal panel unit 50 </ b> B holds the liquid crystal panel 52, a pair of glass plates (a heat diffusion plate 53 and a dustproof plate 54) disposed to face each other with the liquid crystal panel 52 interposed therebetween. And a metal casing 55 (FIG. 3).

  The liquid crystal panel 52 is provided with a liquid crystal, a transparent electrode, an alignment film, etc. between two opposing glass substrates 52a and 52b, and is electrically connected via a flexible cable 52c drawn out between the glass substrates 52a and 52b. When a signal is input, the liquid crystal is driven.

  The liquid crystal panel 52 is disposed between the heat diffusion plate 53 and the dustproof plate 54 facing each other. However, the thermal diffusion plate 53 also functions as a dustproof plate for protecting the liquid crystal panel 52 from scratches and dust. The thermal diffusion plate 53 and the dustproof plate 54 are fixed to the corresponding glass substrate with an adhesive having good thermal conductivity (for example, a silicon-based thermal conductive adhesive). Specifically, the heat diffusing plate 53 is closely fixed to the glass substrate 52a, and the dustproof plate 54 is firmly fixed to the glass substrate 52b. Here, the thermal diffusion plate 53 in close contact with the glass substrate 52a is sufficiently larger than the glass substrate 52a. Therefore, a rectangular frame-shaped non-overlapping region that does not overlap with the panel 52 is formed around the liquid crystal panel 52 on the heat diffusion plate 53 to which the liquid crystal panel 52 is fixed. On the other hand, the dustproof plate 54 in close contact with the glass substrate 52b has substantially the same size as the glass substrate 52b.

  The housing 55 is composed of a main body 56 and a back cover 57, and a liquid crystal panel 52, a heat diffusion plate 53, and a dustproof plate 54 are housed in a housing space formed therebetween. More specifically, the main body 56 is formed with an incident window 56a whose outer dimension is the same as or slightly larger than that of the heat diffusion plate 53 and slightly smaller than the glass substrate 52a of the liquid crystal panel 52 in the center. It has a front plate 56b and side walls 56c raised substantially vertically from the four sides of the front plate 56b.

On the other hand, the back cover 57 has a back plate 57b on which an exit window 57a having the same shape and dimensions as the entrance window 56a is formed, and a side wall 57c raised substantially vertically from two opposite sides of the back plate 57b. . The liquid crystal panel 52 to which the heat diffusion plate 53 and the dustproof plate 54 are fixed is disposed inside the main body 56, and the back cover 57 is covered from the rear of the dustproof plate 54, so that the space between the main body 56 and the back cover 57 is The liquid crystal panel 52 integrated with the heat diffusion plate 53 and the dustproof plate 54 is accommodated and held. The interval D ₁ between the opposing side walls 57 c of the back cover 57 is slightly smaller than the interval D ₂ between the opposing side walls 56 c of the main body 56. Therefore, when mounting the rear cover 57 to the body 56, cover the outside of the side wall 56c facing the body 56 a distance D ₁ of the between the opposing side walls 57c slightly widened. Then, the back cover 57 is fixed to the main body 56 by the elastic restoring force of the side wall 57c.

  Further, the height H of the opposing side wall 56c of the main body 56 is equal to or lower than the total thickness of the heat diffusion plate 53, the liquid crystal panel 52, and the dustproof plate 54. Therefore, when the heat diffusing plate 53, the liquid crystal panel 52, and the dustproof plate 54 are accommodated between the main body 56 and the back cover 57 as described above, the front plate 56b of the main body 56 is in close contact with the heat diffusing plate 53 and the back surface. The cover back plate 57 is in close contact with the dust proof plate 54. More specifically, in the heat diffusion plate 53, a region around a region illuminated by light incident from the incident window 56a of the main body 56 is in close contact with the front plate 56b. The region where the heat diffusing plate 53 is in close contact with the front plate 56b substantially coincides with the above-described non-overlapping region.

  Further, in this example, the front plate 56b of the main body 56 and the heat diffusing plate 53 which are in close contact with each other are bonded with an adhesive having good thermal conductivity (for example, a silicon-based thermal conductive adhesive). Further, the back plate 57b of the back cover 57 and the dust-proof plate 54 which are in close contact with each other are also bonded in the same manner. However, by fixing the main body 56 and the back cover 57 more firmly, the liquid crystal panel 52, the heat diffusion plate 53, and the dustproof plate 54 can be sandwiched and held therebetween. In this case, the front plate 56b and the heat diffusing plate 53 of the main body 56 and the back plate 57b and the dustproof plate 54 of the back cover 57 do not have to be bonded with an adhesive.

  Next, the behavior of light in the liquid crystal panel unit 50B will be described with reference to FIG. The liquid crystal panel unit 50B is arranged at a position and orientation in which light enters from the incident window 56a of the housing 55 (main body 56). That is, the light emitted from the condenser lens 48 </ b> B shown in FIG. 2 is applied to the front plate 56 b of the main body 56. At this time, the light spot irradiated on the front plate 56b is designed to be slightly larger than the incident window 56a. Even when the light irradiation position on the front plate 56b slightly deviates from the design value, the incident window The entire 56a is illuminated. The light incident from the incident window 56 a passes through the thermal diffusion plate 53 and enters the liquid crystal panel 52, and is modulated by the panel 52. The modulated light (image light) passes through the dustproof plate 54 and is emitted from the emission window 57a of the back cover 57 to the outside of the liquid crystal panel unit 50B.

  At this time, a part of the light incident on the liquid crystal panel 52 is lost inside and is converted into heat. The generated heat is diffused to the heat diffusion plate 53 and the dustproof plate 54 through the glass substrates 52 a and 52 b, further diffused to the housing 55, and radiated from the surface of the housing 55. Here, the entire surfaces of the glass substrates 52a and 52b are in close contact with the heat diffusion plate 53 or the dustproof plate 54, respectively, and the heat diffusion plate 53 and the dustproof plate 54 are in close contact with the metal casing 55, respectively. . Accordingly, since the heat conduction path from the liquid crystal panel 52 to the housing 55 is extremely short and the contact area between the members constituting the heat conduction path is large, the heat generated in the liquid crystal panel 52 can be efficiently accommodated in the housing. It can be conducted to 55 and dissipated. Furthermore, the heat diffusion plate 53 that is in close contact with the glass substrate 52a disposed on the light incident side of the liquid crystal panel 52 has a sufficiently large surface area and volume with respect to the glass substrate 52a. In addition, the entire surface of the non-overlapping region occupying most of the heat diffusion plate 53 is in close contact with the main body 56. As a result, the heat generated in the liquid crystal panel 52 can be more efficiently diffused to the heat diffusion plate 53, and the diffused heat can be radiated from the housing 55 more efficiently. In short, the present invention diffuses heat to the surroundings by enlarging the heat diffusion plate 53 in a direction not blocking light entering and exiting the liquid crystal panel 52 (a direction perpendicular to the optical axis), and the enlarged portion is made of metal. The essence is that the heat radiation efficiency is improved by directly contacting the housing 55. Accordingly, even if the heat diffusion plate 53 is disposed between the liquid crystal panel 52 and the back plate 57b, the light incident surface of the heat diffusion plate 53 is brought into contact with the glass substrate 52b, and the light emitting surface is brought into contact with the back plate 57b. Good. In this case, the dustproof plate 54 is disposed between the liquid crystal panel 52 and the front plate 56b.

  In addition, the material of the housing | casing 55, the thermal-diffusion board 53, and the dustproof board 54 is not limited to a specific thing. However, it is clear that a material having excellent thermal conductivity is desirable. In this example, aluminum is selected as the material of the housing 55, and quartz is selected as the material of the heat diffusion plate 53 and the dustproof plate 54. If sapphire is selected as the material of the thermal diffusion plate 53, the thermal diffusivity is further improved.

  The above is the main structure and operation of the liquid crystal panel unit 50B. As described above, the other liquid crystal panel units 50R and 50G shown in FIG. 2 have the same structure and operation. Here, light (image light) emitted from the liquid crystal panel units 50R, 50G, and 50B is synthesized by the XDP 70 and emitted from the projection lens 22. Further, the outside air introduced by the intake fan 23 shown in FIG. 1 is supplied to each of the liquid crystal panel units 50R, 50G, and 50B as cooling air.

  Further, the liquid crystal panel units 50R, 50G, and 50B constitute one independent structure. Specifically, the liquid crystal panel 52 and other components are held by the housing 55. Therefore, when the liquid crystal panel units 50R, 50G, and 50B are arranged in the outer case 1, the units 50R, 50G, and 50B are moved in an arbitrary direction so that the optical axes of the liquid crystal panel 52 and the XDP 70 are aligned and positioned. Can be combined. For example, the liquid crystal panel units 50R, 50G, and 50B can be attached to a base to which the liquid crystal panel units 50R, 50G, and 50B and the XDP 70 are fixed so that they can be displaced in any two or more directions. Further, the liquid crystal panel units 50R, 50G, and 50B can be attached to the arm fixed to the XDP 70 so as to be displaceable in any two or more directions.

(Embodiment 2)
Hereinafter, another example of the embodiment of the projection display device of the present invention will be described. The basic configuration of the projection display apparatus of this example is the same as that of the projection display apparatus of the first embodiment. The projection display apparatus of this example is different from the apparatus of the first embodiment only in the structure of the liquid crystal panel unit. Therefore, description of the common configuration is omitted, and only the liquid crystal panel unit will be described below. In the description of the liquid crystal panel unit, the same reference numerals are used for the common components, and detailed description thereof is omitted.

  FIG. 6 is an exploded perspective view of a liquid crystal panel unit 80 included in the projection display apparatus of this example, and FIG. 7 is a cross-sectional view thereof. The liquid crystal panel unit 80 is different from the liquid crystal panel units 50R, 50G, and 50B of the first embodiment in that a Peltier element 81 is interposed between the thermal diffusion plate 53 and the front plate 56b of the main body 56.

  The Peltier element 81 is formed in a rectangular frame shape in which a rectangular opening 85 for allowing light incident from the incident window 56a to pass therethrough, and heat conduction sheets 82 and 83 are provided on the heat absorption surface and the waste heat surface, respectively. Is provided. The thermal diffusion plate 53 is adhered to the surface of the thermal conductive sheet 82 with an adhesive having a good thermal conductivity (for example, a silicon-based thermal conductive adhesive), and the front plate 56b of the main body 56 is the same. It is adhered to the surface of the heat conductive sheet 83 by the adhesive. Accordingly, the heat generated in the liquid crystal panel 52 and diffused to the heat diffusion plate 53 is absorbed by the Peltier element 81 through the heat conductive sheet 82. Further, waste heat from the Peltier element 81 is diffused and dissipated to the main body 56 via the heat conductive sheet 83. However, if the Peltier element 81 and the liquid crystal panel 52 in which the heat diffusion plate 53 and the dustproof plate 54 are integrated are sandwiched and held by the main body 56 and the back cover 57, the fixing with the adhesive may be omitted. it can. Further, both or one of the heat conductive sheets 82 and 83 can be omitted as necessary. For example, when a sufficient heat dissipation effect is obtained by heat conduction through an adhesive, both or one of the heat conductive sheets 82 and 83 can be omitted.

  The power cable 84 of the Peltier element 81 is drawn to the outside through a notch formed in the side wall 56c of the main body 56. A flexible cable 52c for supplying an electric signal to the liquid crystal panel 52 is also drawn out from the notch. However, this point is common to the first embodiment.

  According to the liquid crystal panel unit 80 having the above structure, the heat generated in the liquid crystal panel 52 is forced to cause heat transfer by the Peltier element 81 and is cooled, so that the liquid crystal panel unit 50R of the first embodiment using only natural heat radiation. , 50G and 50B have higher heat dissipation. However, the liquid crystal panel units 50R, 50G, and 50B of Embodiment 1 have an advantage that they are suitable for thinning because the thickness is reduced by the amount that the Peltier element 81 is not provided. Further, by increasing the area of the heat diffusion plate 53 or increasing the thickness, it is possible to ensure the same heat dissipation as the liquid crystal panel unit 80 of this example. Here, the liquid crystal panel units 50R, 50G, and 50B of the first embodiment are thinner than the liquid crystal panel unit 80 of the present example because the Peltier element 81 is not provided. Therefore, even if the thickness of the thermal diffusion plate 53 is increased, the overall thickness can be suppressed to the same level.

  In addition, according to the present invention, a significant noise reduction can be realized by eliminating the need for a fan for cooling the liquid crystal panel or by weakening the cooling air. However, it is possible to obtain a higher cooling effect by supplying cooling air as in the conventional case.

  Note that the liquid crystal panel unit 80 of this example is thicker than the liquid crystal panel units 50R, 50G, and 50B of the first embodiment by the amount of the Peltier element 81. Therefore, it is obvious that the dimensions of the housing 55 are changed in correspondence with the increase in thickness. In the projection display device of this example, it goes without saying that the liquid crystal panel unit 80 is provided for each color light of R, G, and B.

  Further, in the present example, the light incident surface of the heat diffusing plate 53 is in contact with the heat absorbing surface of the Peltier element 81, and the waste heat surface of the Peltier element 81 is in contact with the front plate 56b. However, it is also possible to bring the light emission surface of the heat diffusion plate 53 into contact with the heat absorption surface of the Peltier element 81 and to bring the waste heat surface of the Peltier element 81 into contact with the back plate 57b. Furthermore, Peltier elements can be disposed on both the light incident surface and the light emitting surface of the thermal diffusion plate 53.

It is a top view which shows the structure of the projection type display apparatus of this invention. FIG. 2 is a schematic structural diagram of the optical engine shown in FIG. 1. It is an external appearance perspective view of the liquid crystal panel unit shown in FIG. It is a disassembled perspective view of the liquid crystal panel unit shown in FIG. It is sectional drawing of the liquid crystal panel unit shown in FIG. It is an external appearance perspective view of the liquid crystal panel unit shown in FIG. It is a disassembled perspective view which shows the modification of a liquid crystal panel unit.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Exterior case 10 Power supply unit 20 Optical engine 21 Light source lamp 22 Projection lens 23, 24 Intake fan 25 Exhaust fan 30 Integrator optical system 31 Illumination optical system 32 Reflector 33a, 33b Lens array 34 Field lens 35 Polarization conversion element 40 Color separation optical system 41 Blue reflective dichroic mirror 42 Green reflective dichroic mirror 43, 44, 47 Reflective mirror 45, 46 Relay lens 50R, 50G, 50B Liquid crystal panel unit 52 Liquid crystal panel 52a, 52b Glass substrate 52c Flexible cable 53 Thermal diffusion plate 54 Dustproof plate 55 Housing Body 56 Main body 56a Incident window 56b Front plate 56c Side wall 57 Back cover 57a Outgoing window 57b Rear plate 57c Side wall 70 XDP
80 LCD panel unit 81 Peltier element 82, 83 Thermal conduction sheet 84 Power cable

Claims (9)

A metal housing including a front plate on which an incident window for light incidence is formed, and a rear plate on which an emission window for light emission is formed;
A liquid crystal panel housed in the casing and illuminated by light incident from the incident window, the first glass substrate being a light incident surface of the liquid crystal panel, and a first light emitting surface of the liquid crystal panel A liquid crystal panel provided with at least a liquid crystal layer, a transparent electrode and an alignment film between the two glass substrates;
Between the front plate and the first glass substrate of the liquid crystal panel, and disposed on the optical path of light incident on the liquid crystal panel, the transparent diameter is larger than the outer diameter of the first glass substrate. And a light heat diffusion plate,
The entire surface of the first glass substrate of the liquid crystal panel is in contact with the light exit surface of the heat diffusion plate,
The area around the light incident area of the light incident surface of the heat diffusing plate is all in contact with the front plate,
A liquid crystal panel unit, wherein a surface area and a volume of the heat diffusion plate are larger than a surface area and a volume of the first glass substrate. A metal housing including a front plate on which an incident window for light incidence is formed, and a rear plate on which an emission window for light emission is formed;
A liquid crystal panel housed in the casing and illuminated by light incident from the incident window, the first glass substrate being a light incident surface of the liquid crystal panel, and a first light emitting surface of the liquid crystal panel A liquid crystal panel provided with at least a liquid crystal layer, a transparent electrode and an alignment film between the two glass substrates;
It is located between the back plate and the second glass substrate of the liquid crystal panel and on the optical path of the light emitted from the liquid crystal panel, and is larger than the outer diameter of the second glass substrate. A translucent heat diffusion plate,
The entire surface of the second glass substrate of the liquid crystal panel is in contact with the light incident surface of the heat diffusing plate,
The area around the area where light is emitted from the light exit surface of the heat diffusion plate is all in contact with the back plate,
The liquid crystal panel unit, wherein a surface area and a volume of the heat diffusion plate are larger than a surface area and a volume of the second glass substrate. A metal housing including a front plate on which an incident window for light incidence is formed, and a rear plate on which an emission window for light emission is formed;
A liquid crystal panel housed in the casing and illuminated by light incident from the incident window, the first glass substrate being a light incident surface of the liquid crystal panel, and a first light emitting surface of the liquid crystal panel A liquid crystal panel provided with at least a liquid crystal layer, a transparent electrode and an alignment film between the two glass substrates;
Between the front plate and the first glass substrate of the liquid crystal panel, and disposed on the optical path of light incident on the liquid crystal panel, the transparent diameter is larger than the outer diameter of the first glass substrate. A light heat diffusion plate;
Between the front plate and the heat diffusion plate, having a Peltier element arranged to avoid the optical path of light incident on the liquid crystal panel,
The entire surface of the first glass substrate of the liquid crystal panel is in contact with the light exit surface of the heat diffusion plate,
The area around the light incident surface of the light incident surface of the heat diffusing plate is all in contact with the heat absorbing surface of the Peltier element,
The waste heat surface of the Peltier element is in contact with the front plate,
A liquid crystal panel unit, wherein a surface area and a volume of the heat diffusion plate are larger than a surface area and a volume of the first glass substrate. A metal housing including a front plate on which an incident window for light incidence is formed, and a rear plate on which an emission window for light emission is formed;
A liquid crystal panel housed in the casing and illuminated by light incident from the incident window, the first glass substrate being a light incident surface of the liquid crystal panel, and a first light emitting surface of the liquid crystal panel A liquid crystal panel provided with at least a liquid crystal layer, a transparent electrode and an alignment film between the two glass substrates;
It is located between the back plate and the second glass substrate of the liquid crystal panel and on the optical path of the light emitted from the liquid crystal panel, and is larger than the outer diameter of the second glass substrate. A translucent heat diffusion plate;
Between the back plate and the heat diffusion plate, having a Peltier element arranged to avoid the optical path of the light emitted from the liquid crystal panel,
The entire surface of the second glass substrate of the liquid crystal panel is in contact with the light incident surface of the heat diffusing plate,
The area around the area where light is emitted from the light emission surface of the heat diffusion plate is all in contact with the heat absorption surface of the Peltier element,
The waste heat surface of the Peltier element is in contact with the back plate,
The liquid crystal panel unit, wherein a surface area and a volume of the heat diffusion plate are larger than a surface area and a volume of the second glass substrate.   The liquid crystal panel unit according to claim 3, wherein the light incident surface of the heat diffusing plate and the heat absorbing surface of the Peltier element are in contact via a heat conductive sheet.   The liquid crystal panel unit according to claim 3 or 5, wherein the waste heat surface of the Peltier element and the front plate are in contact with each other through a heat conductive sheet.   The liquid crystal panel unit according to claim 4, wherein a light emission surface of the heat diffusion plate and a heat absorption surface of the Peltier element are in contact with each other through a heat conductive sheet.   The liquid crystal panel unit according to claim 4 or 7, wherein a waste heat surface of the Peltier element and the back plate are in contact with each other through a heat conductive sheet. A projection display device that combines light modulated by a plurality of liquid crystal panel units with a prism, and projects the combined light through a projection lens,
A projection display device, wherein the liquid crystal panel unit is the liquid crystal panel unit according to any one of claims 1 to 8.

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