Optics: image projectors – Composite projected image – Multicolor picture
Reexamination Certificate
2001-06-27
2004-04-27
Adams, Russell (Department: 2851)
Optics: image projectors
Composite projected image
Multicolor picture
C353S119000, C353S122000, C353S020000
Reexamination Certificate
active
06726330
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of Invention
The present invention relates to an electro-optical apparatus that includes a liquid crystal panel, and a projector that employs the electro-optical apparatus.
2. Description of Related Art
Projectors are known that separate a light beam emitted from a light source into beams of three colors, RGB, through a dichroic mirror, modulate the respective beams of colors on the basis of image information through three liquid crystal panels, synthesize the modulated light beams through a cross-dichroic prism, and expand and project a color image through a projection lens.
This type of projector is fabricated by combining components, including an inner case, a liquid crystal panel, a prism, and a projection lens. In the assembly process, where dust or fluff may electrostatically adhere to an image forming region of an electro-optical apparatus formed of liquid crystal panels, and the shadow of the dust or fluff may be projected onto a projection surface, leading to deterioration of image quality.
Furthermore, after the delivery of a product, when a user uses the product, minute dust passing through an air filter, or dust or fluff that has accumulated in the inner case during a manufacturing process, is blown up by a cooling fan and adheres to the liquid crystal panels. The shadow of the dust or fluff may also be projected on an image, leading to deterioration of image quality.
SUMMARY OF THE INVENTION
If dust or fluff adheres to an electro-optical apparatus after assembly as mentioned above, then it is necessary to disassemble a projector body to remove the dust or fluff by using various types of equipment, such as an air gun, a blower, and a dust collector, and reassemble the projector body thereafter. This is required because the gap between the liquid crystal panels constituting the electro-optical apparatus and the prism is so narrow that it is difficult to blow air in by an air gun or similar apparatus. Furthermore, the dust or fluff electrostatically adhering to the electro-optical apparatus cannot be easily removed, and it takes a long time to remove it. In addition, considerable equipment is necessary to remove dust or fluff.
Furthermore, in order to prevent the deterioration of image quality, it is substantially essential to provide the electro-optical apparatus with dust-proof glass to blur the shadow of dust projected onto an image. The dust-proof glass is used to shift the surface, to which dust or the like adheres, from the focal position of a projection lens so as to make the dust less conspicuous on a projection surface, even if dust or the like adheres to a surface (one surface or both surfaces) of a liquid crystal panel or the like.
Attempts to prevent the deterioration of image quality caused by dust or the like have been difficult because complicated work or considerable equipment is required and the number of components is increased in some cases, and manufacturing or maintenance costs are higher.
An object of the present invention is to provide an electro-optical apparatus and a projector that reduce such complicated work, considerable equipment, and an increase in the number of components, enable efficient manufacture and maintenance, and permit a reduction in manufacturing cost or maintenance cost.
To this end, according to the present invention, an electro-optical apparatus is provided that is equipped with a pair of substrates and an electro-optical element sandwiched between the pair of substrates. An antistatic layer is provided on the outer surface of at least one of the pair of substrates.
According to the present invention, since the antistatic layer is formed on the surface of the substrate, even if static electricity is generated on the surface of the substrate, the static electricity escapes to the exterior of the apparatus through the antistatic layer. Thus, electrification to the substrates of the electro-optical apparatus can be reduced, making it possible to minimize the adherence of dust, fluff, or the like to a surface of a substrate. This minimizes deterioration of images caused by the adherence of dust, fluff, or the like during a manufacturing process or during the use by a user.
Moreover, the above feature obviates the need for or simplifies the work required to remove dust, fluff, or the like from a substrate of an electro-optical apparatus and the need for equipment required therefor. Hence, the manufacture and maintenance of the electro-optical apparatus can be efficiently performed, and the cost required for the manufacture and maintenance can be reduced.
In addition, the need for dust-proof glass, which has hitherto been substantially essential, can be obviated. If the need for the dust-proof glass is obviated, then the number of components can be reduced, so that the manufacturing cost can be reduced from this respect also.
Furthermore, since the electrification to a substrate can be reduced, in the case of an electro-optical device equipped with a TFT (thin-film transistor) device or the like, the destruction of the TFT device attributable to electrical discharge can be prevented, and defects in a manufacturing process can be reduced.
In the above, in the present invention, the antistatic layer is preferably formed of an inorganic material. The inorganic material may be exemplified by a composition provided with silica and conductive particulates.
An organic material can be used for the antistatic layer; however, the organic material may cause a problem, such as deterioration or discoloration attributable to light. In contrast thereto, forming the antistatic layer by an inorganic material solves the problem with an organic material, making it possible to prevent the adherence of dust or fluff to a surface of a substrate over an extended period of time.
The conductive particulates include, for example, metals, such as Pd, Pt, Ru, Ag, Au, Ti, In, Cu, Cr, Fe, Zn, Sn, Ta, W, and Pb, or borides, such as HfB
2
, ZrB
2
, LaB
6
, CeB
6
, YB
4
, and GdB
4
, or carbides, such as TiC, ZrC, HfC, TaC, SiC, and WC, or nitrides, such as TiN, ZrN, and HfN, or semiconductors, such as Si and Ge, or carbon. An appropriate one can be selected from among the above.
Preferably, the antistatic layer has a resistance value ranging from 10
6
to 10
9
&OHgr;/□.
If the resistance value exceeds 10
9
&OHgr;/□, the electrical resistance will be excessively high, and the antistatic layer will no longer be able to sufficiently release electricity. This may prevent antistatic effect from being fully displayed.
A first projector in accordance with the present invention is provided with the electro-optical apparatus described above.
A second projector in accordance with the present invention is provided with a light source, a color separating optical system that separates a light beam emitted from the light source into a plurality of colors, a plurality of electro-optical apparatuses that modulate the color beams that have been separated by the color separating optical system, a prism that synthesizes the color beams that have been modulated by these electro-optical apparatuses, and a projection lens that projects light emitted from the prism, the electro-optical apparatuses having the construction described above.
In the projector according to the present invention, since the antistatic layer is formed on the surface of the substrate, even if static electricity is generated on the surface of the substrate, the static electricity escapes to the exterior of the apparatus through the antistatic layer. Thus, electrification to the surfaces of the substrates of the electro-optical apparatus can be reduced, making it possible to minimize the adherence of dust, fluff, or the like to the surface of a substrate. This minimizes deterioration of images caused by the adherence of dust, fluff, or the like during a manufacturing process or during the use by a user.
Moreover, the above feature obviates the need for or simplifies the work for removing dust, fluff, or the like from a substrate of an electro-optical appara
Adams Russell
Oliff & Berridg,e PLC
Seiko Epson Corporation
Sever Andrew
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