Optics: image projectors – Temperature control – Blower
Reexamination Certificate
1999-06-30
2001-03-20
Dowling, William (Department: 2851)
Optics: image projectors
Temperature control
Blower
Reexamination Certificate
active
06203159
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of Invention
The present invention relates to a projection display device, and particularly to a technique for miniaturizing a display device and cooling a modulator provided in the device with a good balance.
2. Description of Related Art
A conventional known projection display device comprises a light source lamp, an optical system for optically processing a light beam emitted from the light source to form an optical image corresponding to image information, a projection lens for enlarging and projecting the image formed by the optical system on a projection screen, and a power source for supplying power for driving the device. In such a projection display device, a modulator is generally arranged on a predetermined mounting surface.
Also, the projection display device is widely used for multimedia presentations in a conference, a society meeting, a trade show, and the like. A projection display device is maintained in a state where it is installed in a meeting room for presentations, and if required, it is sometimes carried in or transferred to another place after presentation, and stored therein. Therefore, it is necessary to improve portability in order to facilitate carrying, and thus further miniaturization is required.
In order to miniaturize the device, various components are closely arranged in the device, causing difficulties in a flow of cooling air sucked by a fan or the like. Therefore, means for effectively cooling the components, which generate heat, are provided. Particularly, since a modulator is easily heated, in order to cool the modulator, a cooling air intake is provided below the modulator, and an intake fan is arranged below the modulator to suck cooling air to force the modulator to be cooled.
However, the cooling air sent to the modulator by the intake fan is passed through the cooling air intake provided in the mounting surface from the outlet of the rotating intake fan, and is spirally blown, thereby causing the problem of producing nonuniformity in cooling of the modulator.
SUMMARY OF THE INVENTION
The present invention provides a projection display device permitting well-balanced cooling of a light modulator.
A projection display device of the present invention includes a light source; a light modulator for modulating light emitted from the light source; a projection optical system for projecting the light modulated by the light modulator; a mounting surface for mounting the light modulator thereon; a fan that supplies cooling air to the light modulator, the fan disposed on a side of the mounting surface opposite to a side on which the light modulator is mounted; and an air inlet that introduces cooling air to the light modulator at a position adjacent the mounting surface where the light modulator is mounted; the air inlet being comprised of first and second regions, the first region being opposite to the spiral direction of the cooling air supplied to the light modulator from the fan, the first region and the second region being on opposite sides of a line of intersection of the air inlet and a surface crossing the light modulator and the mounting surface at right angles, and including the center of the light modulator, the first region being wider than the second region.
In the present invention, the air inlet is enlarged to the side opposite to the air spiral, and the cooling air is blown from the enlarged portion, thereby achieving well-balanced cooling of the light modulator. This leads to the achievement of the object of the present invention.
A projection display device of the present invention also includes a plurality of light modulators for respectively modulating lights of a plurality of colors; a color synthesis optical system for synthesizing the light modulated by the light modulators; a projection optical system for projecting the light synthesized by the color synthesis optical system; the light modulators and the color synthesis optical system being mounted on a mounting surface; a fan that supplies cooling air to the light modulators, the fan being disposed on a side of the mounting surface opposite to a side where the light modulators and the color synthesis optical system are mounted, the cooling air being supplied by the fan in a spiral direction; and air inlets that introduce cooling air to each of the light modulators at a position adjacent the mounting surface where each of the light modulators is mounted; the air inlets being comprised of first and second regions, the first region being formed opposite to the spiral direction of the cooling air supplied to the light modulators from the fan, the first region being wider than the second region.
In the present invention, each of the air inlets is enlarged to the side opposite to the air spiral, and the cooling air is blown from the enlarged portions, thereby achieving well-balanced cooling of the light modulators and the color synthesis optical system.
The color synthesis optical system comprises a prism having a color synthesis film, and a plurality of the light modulators are preferably arranged opposite to the light incident surfaces of the prism.
In the present invention, the prism is also cooled by the cooling air from the air inlets with a good balance.
Also, a straightening vane is preferably provided in the air inlet, for arranging the flow of the cooling air.
In the present invention, the cooling air sucked by the intake fan is efficiently sent to the straightening vane, thereby efficiently cooling the light modulators and the color synthesis optical system with a good balance.
The straightening vane is preferably provided at a position of the line of intersection in the air inlet.
In the present invention, since the mounting position of the straightening vane is determined, the straightening vane can be mounted at a correct position.
The mounting surface is provided with a recessed portion for arranging the fan, and the straightening vane has substantially the same depth as the recessed portion.
In the present invention, the straightening vane does not interfere with mounting of the light modulators and the like.
In the present invention, the mounting surface and a head body having a vertical surface substantially perpendicular to the mounting surface are provided, and a plurality of columnar projections are provided on the vertical surface so that a projection lens which constitutes the projection optical system is preferably fixed on the basis of the ends surfaces of the projections.
In the present invention, in order to precisely position the projection lens, positioning may be performed by shaving the end surfaces of the projections without shaving the entire surface of the vertical surface, thereby decreasing the required labor.
REFERENCES:
patent: 5418586 (1995-05-01), Fujimori et al.
patent: 6007205 (1999-12-01), Fujimori
Dowling William
Oliff & Berridge PLC.
Seiko Epson Corporation
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