JP2004126421A - Projective display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To sharply reduce dust or the like stuck to an optical element part without damaging cooling performance in a projective display device. <P>SOLUTION: In the projective display device provided with a light source device, an illumination device, an optical element part including a liquid crystal light bulb and a polarizing plate, and a suction fan for picking up outside air for cooling the optical element part, a sponge-like angular dust removing filter 9 is arranged in an air passage 2 disposed between the suction fan 2 and the optical element part, furthermore , a filter for altermative dust removals in drawing in fan's open air intake . <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a cooling mechanism for an optical element used in a projection display device such as a liquid crystal projector.
[0002]
[Prior art]
Projection type display devices such as liquid crystal projectors are widely used for presentations at companies, classes at schools, information display applications at public facilities, etc. by enlarging not only natural images but also characters, tables and graphics. There is a growing need for projection display means. In recent years, in addition to demands for downsizing and weight reduction of devices, demands for higher luminance and higher definition of a screen in order to improve display performance are increasing.
[0003]
2. Description of the Related Art In a projection display device such as a liquid crystal projector, light from a lamp, which is a light source, is condensed by a lens, guided to R, G, B and other liquid crystal panels through mirrors and multi-lenses, and passed through a polarizing plate. , The polarization plane is rotated according to the video signal, and the light emitted from the liquid crystal panel is passed through a polarizing plate to form R, G, and B images. Thereafter, the R, G, and B images are combined into one by a prism, and enlarged and displayed as a color image via a projection lens. The optical elements such as R, G, and B liquid crystal light valves, polarizing plates, and prisms are configured as one unit (optical element unit), and are the most important units of the liquid crystal projector.
[0004]
In recent years, there has been a strong demand for higher brightness of liquid crystal projectors. For this reason, the brightness of a screen has been improved by increasing the aperture ratio of a liquid crystal light valve or increasing the brightness of a lamp as a light source.
[0005]
The optical element section including the liquid crystal light valve, the polarizing plate, and the like is composed of a polarizing substrate, a driving IC, glass, a liquid crystal cell, and the like. When the apparatus is used, the heat energy emitted from the light source and the heat emitted from itself are used. And it gets hotter. If the temperature of the optical element portion rises excessively, problems such as a decrease in the performance of the liquid crystal light valve and a shortened life will occur. Therefore, a cooling mechanism for keeping the optical element portion at a constant temperature is required.
[0006]
A polarizing plate is arranged on the incident side of the liquid crystal panel to obtain linearly polarized light from natural light from the light source, and a polarizing plate is separately arranged on the exit side for converting the rotation of the polarization plane of the liquid crystal panel into light intensity. Are disposed. The polarizer absorbs about 60% of the light and converts the absorbed light into heat energy, so the polarizer itself becomes hot. Therefore, a cooling mechanism is required to maintain the performance of the polarizing plate. As described above, in the projection display device, a mechanism for intensively cooling the optical element unit is indispensable, but an air cooling system that can be realized at low cost is generally adopted as the cooling mechanism.
[0007]
As the above air cooling system, there is an air cooling system that includes an intake fan that sucks in outside air, and two air guide paths that send the sucked outside air to the optical element unit and the light source device, respectively, so that the outside air is directly applied to the optical element unit ( See, for example, Patent Document 1.
[0008]
There is also a type in which outside air sucked from an intake fan is passed only through a metal filter provided in a hole of a metal plate cooled by a Peltier element, whereby cooling air is efficiently supplied to a liquid crystal panel. (See, for example, Patent Document 2).
[0009]
Further, there is also a device in which dust contained in the outside air is removed by passing the sucked outside air through a charging filter (for example, see Patent Document 3).
[0010]
In addition, there is a filter that rotatably supports a filter that filters dust contained in sucked outside air, and reduces the number of filter replacements by sequentially using a portion of the filter that is not clogged (for example, Patent Document 4).
[0011]
[Patent Document 1]
JP 2001-133885 A [Patent Document 2]
JP 2000-267190 A [Patent Document 3]
JP 2002-174855 A [Patent Document 4]
Japanese Patent Application Laid-Open No. 9-200664
[Problems to be solved by the invention]
In the cooling mechanism described in Patent Literature 1, a filter for removing dust contained in the outside air is disposed at the suction port of the intake fan. However, if the filter is fine, a sufficient amount of the outside air cannot be sucked and the cooling performance is low. You will need to use something very coarse as it will be damaged. For this reason, very small dust cannot be removed, and if outside air is directly applied to the optical element, they adhere to the optical element. In addition, during use of the device, a current flows through the liquid crystal light valve of the optical element portion, and the device is always charged. Therefore, the liquid crystal light valve absorbs dust and dust having a size of 1 μm or less, so that the amount of dust and dust attached increases accordingly. The attached dust is enlarged and projected through the lens, appears largely on the display screen, and is recognized as deterioration in image quality.
[0013]
The cooling mechanism described in Patent Documents 2, 3, and 4 also has a structure in which the outside air sucked is blown directly to the optical element portion, and it is difficult to achieve both cooling performance and dust removal performance in Patent Document 1 described above. Have the same problem as the cooling mechanism of the above.
[0014]
The present invention has been made in view of the above problems, and an object of the present invention is to make it possible to significantly reduce dust, dust, and the like adhering to an optical element portion without impairing cooling performance in a projection display device. To provide a projection display device with high image quality and long life.
[0015]
[Means for Solving the Problems]
An object of the present invention is to provide a projection display device including a light source device, a lighting device, an optical element unit including a liquid crystal light valve and a polarizing plate, and an intake fan for taking in outside air for cooling the optical element unit. This is achieved by providing, for example, a sponge-like square filter in the air guide passage disposed between the two.
[0016]
The above object is also achieved in a projection display device including a light source device, a lighting device, an optical element unit including a liquid crystal light valve and a polarizing plate, and an intake fan that takes in outside air for cooling the optical element unit. A first dust removal filter is provided at the intake port, and a sponge-shaped square second dust removal filter, for example, is provided in an air guide passage provided between the intake fan and the optical element portion. It is achieved by providing.
[0017]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 is a perspective view showing a configuration of a cooling mechanism of a projection display device according to an embodiment of the present invention, and FIG. 2 is a top view thereof. The cooling mechanism of the present embodiment includes an intake fan 1 that takes in outside air, and a wind guide path 2 that guides outside air taken from the intake fan 1 to an optical element unit 3.
[0018]
The optical element section 3 includes a liquid crystal light valve 3a for G color, a liquid crystal light valve 3b for B color, a liquid crystal light valve 3c for R color, and a prism that combines light of each color from these liquid crystal light valves and sends the light to the projection lens 6. As an integrated unit. Polarizing plates are disposed between the liquid crystal light valves 3a, 3b, 3c and the prism 4, respectively.
FIG. 3A shows an example of the arrangement of the filter 9 in the air duct 2. FIG. 3B is a perspective view in which the wall of the air guide path 2 is partially cut so that the arrangement state is easy to see.
[0019]
FIG. 4A is a perspective view illustrating the configuration of the entire optical engine of the projection display device according to the present embodiment. As shown in FIG. 1, the optical engine includes a light source device 5, an intake fan 7 for taking in outside air for cooling the light source device 5, a projection lens 6, an intake fan 1 for taking in outside air for cooling the optical element unit 3, an exhaust fan 10, The lighting unit 8 is included. FIG. 4B is a view of the optical engine viewed from the back. As shown in FIG. 4B, the air guide path 2 concentrates the outside air sucked by the intake fan 1 on the optical element unit 3 that is weak to heat. It is arranged to spray.
[0020]
Next, the operation of the projection display device of the present embodiment will be described. The light emitted from the lamp in the light source device 5 passes through the illumination unit 8 composed of a lens, a mirror, and the like, reaches the optical element unit 3, is separated into R, G, and B colors, and is separated into R, G, and B colors. The light enters the liquid crystal light valves 3a, 3b, 3c, respectively. As described above, the optical element unit 3 includes a liquid crystal light valve and a polarizing plate, and a voltage output as a video signal from a built-in IC is applied to the liquid crystal light valve, and the polarizing plate absorbs about 60% of light. As a result, thermal energy is accumulated in the optical element portion and becomes hot.
[0021]
Therefore, the intake fan 1 is rotated, and the optical element is cooled by the sucked outside air. In the present embodiment, the air guide path 2 has a largely curved shape of approximately 90 degrees in order to guide the sucked outside air smoothly and concentrate it on the optical element portion 3. Further, since the filter 9 for removing dust, dust and the like contained in the outside air is installed in the air guide path 2, impurities such as dust and dust contained in the sucked outside air are removed.
[0022]
The outside air purified by the filter 9 becomes air for cooling the optical element. Further, at this time, if fins or the like for dividing the air flow are provided so that the cooling air is applied to both of the opposed liquid crystal light valves, the optical element section 3 can be cooled more effectively. Of course, since impurities such as dust and dirt are removed from the cooling air by the filter 9, dust and dirt do not adhere to the liquid crystal light valve.
[0023]
As described above, in the present embodiment, the sucked outside air travels in the horizontal direction and enters the filter 9, where impurities such as dust and dirt contained in the outside air are blocked, and the purified outside air flows out of the filter 9. To move vertically to cool the liquid crystal light valve. The filter 9 has a role of removing impurities, and it is necessary to have a sufficient impurity removing ability. However, if the amount of air passing through the filter 9 is small, the temperature of the liquid crystal light valve becomes high, which affects the life. It is also necessary to have For this reason, in the present embodiment, a sponge-shaped square filter excellent in both the impurity removing ability and the passing air volume is used, and both high impurity removing ability and high cooling ability are achieved.
[0024]
In addition, the removal ability (absorption rate of dust, dust, etc.) of the sponge type filter 9 varies depending on the hole opening efficiency (expansion ratio), dimensions such as length, width, thickness, etc. Can be set accordingly. In the present embodiment, a dust removal filter may be provided at the outside air intake of the suction fan 1, and in that case, the dust removal capability is further improved.
[0025]
【The invention's effect】
According to the present invention, since the dust removal filter having both the impurity removing ability and the passing air volume is provided in the air guide path provided between the intake fan and the optical element, the cooling performance is impaired. It is possible to greatly reduce dust, dust, and the like adhering to the optical element portion without providing a projection display device with high image quality and long life.
[Brief description of the drawings]
FIG. 1 is a perspective view illustrating a configuration of a cooling mechanism of a projection display device according to an embodiment of the present invention.
FIG. 2 is a top view illustrating a configuration of a cooling mechanism of the projection display device according to the embodiment of the present invention.
FIG. 3 is a diagram illustrating a filter arranged in an air guide path of the projection display device according to the embodiment of the present invention.
FIG. 4 is a perspective view illustrating an overall configuration of an optical engine of the projection display device according to the embodiment of the present invention.
[Explanation of symbols]
Reference Signs List 1 intake fan, 2 air guide path, 3a G color liquid crystal light valve, 3b B color liquid crystal light valve, 3c R color liquid crystal light valve, 4 prism, 5 light source device, 6 projection lens, 7 lamp cooling fan, 8 lighting unit, 9 filters, 10 exhaust fans.

Claims (4)

A light source device, a lighting device, an optical element portion including a liquid crystal light valve and a polarizing plate, and a projection display device including an intake fan that takes in outside air for cooling the optical element portion,
A projection display device, wherein a dust removal filter is provided in an air guide passage provided between the intake fan and the optical element unit. The projection display device according to claim 1, wherein the dust removing filter is a sponge-shaped square filter. A light source device, a lighting device, an optical element portion including a liquid crystal light valve and a polarizing plate, and a projection display device including an intake fan that takes in outside air for cooling the optical element portion,
A first dust removal filter is provided at an outside air intake of the intake fan, and a second dust removal filter is provided within an air guide path provided between the intake fan and the optical element unit. A projection display device characterized by the above-mentioned. 4. The projection display device according to claim 3, wherein the second dust removal filter is a sponge-shaped square filter. 5.

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