JP2004233387A - Projection device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To more efficiently cool a liquid crystal panel in a projection device. <P>SOLUTION: The projection device is equipped with a light source 1 and the liquid crystal panel 7 irradiated with light from the light source 1 and provided with polarizing plates 73, 74 in a cabinet 2. The liquid crystal panel 7 is constructed by sealing in liquid crystal molecules between transparent substrates 70, 71 and is attached to a radiator 4. The substrates 70, 71 of the liquid crystal panel 7 are directly held between a pair of the radiators 4, 5, and the polarizing plates 73, 74 are respectively disposed inside each of the radiators 4, 5. Also an additional optical member 8 is disposed so as to be placed opposite to the polarizing plate 73 inside the radiator 4 in addition to the polarizing plate 73. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a projection device that displays an image on a screen.
[0002]
[Prior art]
FIG. 5 is a plan view showing the inside of a conventional projection device (for example, see Patent Document 1). A light source (1) is provided in the cabinet (2), and the indeterminate polarized light emitted from the light source (1) is reflected by a reflector (10) and travels straight. On the optical path from the light source (1), a lens array body (3) (30) configured by arranging a plurality of convex lenses vertically and horizontally, dichroic mirrors (60) (61) inclined with respect to the optical path, R, Three liquid crystal panels (7) (7a) (7b) corresponding to the three primary colors G and B and total reflection mirrors (62) (63) (64) (65) are provided. A color combining prism (66) and a projection lens (6) are provided at the front end of the cabinet (2), and a screen (20) is provided in front of the cabinet (2) so as to face the projection lens (6). Have been.
[0003]
The dichroic mirror (60) on the side of the light source (1) allows only red light to pass therethrough, and the passed light is reflected by the total reflection mirror (65) to irradiate the liquid crystal panel (7) for red light. On the other hand, of the light reflected by the dichroic mirror (60), green light is reflected by the dichroic mirror (61), and the reflected light illuminates the liquid crystal panel (7a) for green light. The blue light that has passed through the dichroic mirror (61) is reflected by the total reflection mirrors (63) and (64) and then irradiates the blue light liquid crystal panel (7b). Light that has passed through the liquid crystal panels (7), (7a), and (7b) for red light, green light, and blue light enters the color combining prism (66). An image corresponding to each of red, blue and green lights is synthesized by the color synthesizing prism (66), and is projected onto the screen (20) by the projection lens (6).
[0004]
Since the temperature of the liquid crystal panel (7) rises in response to the light from the light source (1), it needs to be cooled. FIG. 6 is an exploded perspective view of a structure for air-cooling the liquid crystal panel (7), and FIG. 7 is a cross-sectional view of FIG. 6 cut along a plane including the line AA. The liquid crystal panel (7) is sandwiched between radiators (4) formed with a number of fins (40) (40), and polarizing plates (73) (74) are attached to the outside of the radiators (4). As is well known, the liquid crystal panel (7) transmits only one of the indeterminate polarized lights from the light source (1). As is well known, the liquid crystal panel (7) is formed by stacking transparent substrates (70) and (71) and sealing liquid crystal molecules (not shown) between the substrates (70) and (71).
The liquid crystal panel (7) is generally housed in a metal frame (78) as shown in FIG.
[0005]
[Patent Document 1]
JP-A-2000-147472 (FIG. 1)
[0006]
[Problems to be solved by the invention]
In recent years, higher brightness of a projected image has been demanded, and a higher output has been demanded of the light source (1). Specifically, a brightness of about 4000 lumens, which is about 20 times that of 7 to 8 years ago, is required. Therefore, the temperature of the liquid crystal panel (7) irradiated to the light source (1) is easily increased, and a more effective cooling structure is required.
The applicant has studied the cooling structure in various ways, and found that the heat transfer efficiency was reduced by attaching the heat radiator (4) to the metal frame (78).
An object of the present invention is to cool a liquid crystal panel more efficiently.
[0007]
[Means for solving the problem]
The substrates (70) and (71) of the liquid crystal panel (7) are directly sandwiched between the pair of heat radiators (4) and (5), and the polarizing plates (73) and (74) are placed in the respective heat radiators (4) and (5). Is provided.
[0008]
[Action and effect]
Since the substrates (70) and (71) are directly sandwiched between the heat radiators (4) and (5), compared with the conventional structure in which the liquid crystal panel (7) is held via the frame (78). , Heat conduction efficiency is improved. Thereby, the liquid crystal panel (7) can be cooled more efficiently, and the output of the light source (1) can be increased.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
(overall structure)
Hereinafter, an example of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a plan view showing the inside of the projection device. A light source (1) is provided at the rear end of the cabinet (2), and the indeterminate polarized light emitted from the light source (1) is reflected by the reflector (10) and travels straight. On the optical path from the light source (1), a cut filter (11) for removing ultraviolet rays and infrared rays, a lens array body (3) (30) constituted by arranging a plurality of convex lenses vertically and horizontally, A polarization beam splitter (85) that emits light in accordance with either a wave or an S wave, dichroic mirrors (60) and (61) that are inclined with respect to the optical path, and three liquid crystal panels corresponding to the three primary colors of R, G, and B ( 7) (7a) (7b) and total reflection mirrors (62) (64) (65) are provided.
A projection lens (6) is provided at a front end of the cabinet (2), and a screen (20) is provided in front of the cabinet (2) so as to face the projection lens (6). The optical path from the dichroic mirrors (60) and (61) to the projection lens (6) is the same as the conventional one.
[0010]
The present embodiment is characterized in that the liquid crystal panel (7) is cooled. FIG. 2 is a plan view of the radiators (4) and (5) for cooling the liquid crystal panels (7), (7a) and (7b), and FIG. 3 is a front view of FIG.
The three liquid crystal panels (7), (7a) and (7b) are attached to the base plate (9) attached to the respective surfaces of the color combining prism (66) via the emission side radiator (5). The emission-side heat radiator (5) is formed by arranging a number of fins (40) (40) side by side, and an emission-side polarizing plate (73) is provided inside.
An incident side radiator (4) is attached to the opposite side of the output side polarizing plate (5) with the liquid crystal panels (7), (7a) and (7b) interposed therebetween. A side polarizing plate (74) is provided. The liquid crystal panel (7) is sandwiched between both radiators (4) and (5), and the radiators (4) and (5) are fixed by screws (54). An axial flow type fan (55) is provided below the color combining prism (66) and the liquid crystal panels (7), (7a) and (7b), and the liquid crystal panels (7), (7a) and (7b) are air-cooled. . The fan (55) may be a sirocco fan instead of an axial fan.
[0011]
In order to attach the liquid crystal panels (7) (7a) (7b) to the color combining prism (66), the following procedure is performed. First, the center of the screen of the liquid crystal panel (7a) for green light is made to coincide with the optical axis of the color combining prism (66), and the base plate (9) and the emission side radiator (5) are fixed with solder or an adhesive.
Next, the convergence adjustment and the back focus adjustment of the liquid crystal panel (7) for red light are performed with reference to the display screen of the liquid crystal panel (7a) for green light. Here, the convergence adjustment means that the liquid crystal panel (7) for red light is moved up and down and rotated in a plane perpendicular to the optical axis, and the optical axis of the liquid crystal panel (7) is changed to the liquid crystal panel for green light. (7a) refers to adjustment to match the optical axis. In addition, the back focus adjustment refers to an adjustment for finely adjusting the distance from the projection lens (6) to the liquid crystal panel (7) to accurately project an image on the screen (20) (see Japanese Patent No. 3357843).
After the convergence adjustment and the back focus adjustment, the base plate (9) and the emission side radiator (5) are fixed by solder or an adhesive. Similarly, for the blue light liquid crystal panel (7b), after the convergence adjustment and the back focus adjustment, the base plate (9) and the emission-side heat radiator (5) are fixed with solder or an adhesive. Either the liquid crystal panel (7b) for blue light or the liquid crystal panel (7) for red light may be adjusted first.
[0012]
Each of the polarizing plates (73) and (74) is formed of a member having a high thermal conductivity such as sapphire glass, and the thermal conductivity is set to 40 to 45 W / mK. The radiators (4) and (5) are made of aluminum die-cast, and have a relatively high thermal conductivity of about 200 W / mK. The polarizing plates (73) and (74) are bonded to the radiators (4) and (5) with a high thermal conductive silicon-based adhesive to enhance the heat radiation effect.
[0013]
As shown in FIG. 4, an additional optical member (8) may be provided in addition to the polarizing plates (73) and (74) in the incident side radiator (4) and the exit side radiator (5). The optical member (8) faces the polarizing plates (73) and (74) substantially in parallel with an interval of 1-2 mm. The optical member (8) corresponds to, for example, an additional polarizing plate or a viewing angle widening film. Here, the viewing angle widening film is an optical compensation film in which the orientation angle of the liquid crystal molecules sealed therein changes continuously along the thickness direction of the film. The image looks sharp even when viewed diagonally from the front. Discotic liquid crystals having a disc shape can be used as the liquid crystal molecules sealed in the viewing angle widening film.
In FIG. 4, for convenience of explanation, only a liquid crystal panel (7a) corresponding to green light is shown, but a radiator (7) (7b) attached to liquid crystal panels (7) (7b) corresponding to red light and blue light is illustrated. 4) An optical member (8) may be provided in (5).
[0014]
Since the substrates (70) and (71) are directly sandwiched between the heat radiators (4) and (5), the liquid crystal panel (7) is held via the frame (78) as in the related art. , Heat conduction efficiency is improved. As a result, the liquid crystal panel (7) can be cooled more efficiently, and the output of the light source (1) can be increased.
[0015]
The description of the above embodiments is intended to explain the present invention, and should not be construed as limiting the invention described in the claims or reducing the scope thereof. Further, the configuration of each part of the present invention is not limited to the above-described embodiment, and it is needless to say that various modifications can be made within the technical scope described in the claims.
[Brief description of the drawings]
FIG. 1 is a plan view showing the inside of a projection device.
FIG. 2 is a plan view of a radiator that cools a liquid crystal panel.
FIG. 3 is a front view of FIG. 2;
FIG. 4 is a plan view of another radiator.
FIG. 5 is a plan view showing the inside of a conventional projection device.
FIG. 6 is an exploded perspective view of a structure for air-cooling a liquid crystal panel.
FIG. 7 is a cross-sectional view of FIG. 6 cut along a plane including line AA.
FIG. 8 is a perspective view of a conventional liquid crystal panel.
[Explanation of symbols]
(1) Light source (2) Cabinet (4) Heat radiator (5) Heat radiator (7) Liquid crystal panel (9) Fan

Claims (2)

A cabinet (2) includes a light source (1) and a liquid crystal panel (7) irradiated with light from the light source (1) and having polarizing plates (73) and (74), and the liquid crystal panel (7) is transparent. The liquid crystal molecules are sealed between the transparent substrates (70) and (71), and the projection device is mounted on the heat radiator (4).
The substrates (70) and (71) of the liquid crystal panel (7) are directly sandwiched between the pair of heat radiators (4) and (5), and the polarizing plates (73) and (74) are placed in the respective heat radiators (4) and (5). A projection device, which is provided. 2. The projection device according to claim 1, wherein a further optical member (8) is provided in the radiator (4), (5) in addition to the polarizing plate (73) so as to face the polarizing plate (73). 3. .

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