Optics: image projectors – Housing
Reexamination Certificate
2001-10-26
2003-10-28
Dowling, William (Department: 2851)
Optics: image projectors
Housing
C353S057000, C353S061000
Reexamination Certificate
active
06637895
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a projection display provided with an optical unit to optically process the luminous flux emitted from a light source lamp unit and project the magnified image on a projection surface by a projection lens unit, a power source unit to feed the power to the optical unit, and an external case to store the optical unit and the power source unit.
2. Description of Related Art
A projection display provided with an optical unit to optically process the luminous flux emitted from a light source lamp unit and project the magnified image on a projection surface by a projection lens unit, a power source unit to feed the power to the optical unit, an external case to store the optical unit and the power source unit, and a plurality of circuit substrates to control the optical unit has been conventionally known.
The optical unit of the projection display is provided with a color separation optical system to separate the luminous flux emitted from a light source lamp into the luminous flux of the primary colors, a modulation system to emit each of the separated luminous flux as the modulated luminous flux based on the image information, and a color synthesis optical system to synthesize each modulated luminous flux and emit it to the projection lens unit, in addition to the light source lamp unit and the projection lens unit which are mentioned above.
The color separation optical system and the modulation system of the optical unit are stored and arranged together with the light source lamp unit in a light guide in which the prescribed optical path is secured. The light guide is split into an upper part and a lower part to hold the optical elements such as the color separation optical system from the upper part and the lower part.
The color synthesis optical system and the projection lens unit of the optical unit are mounted on a head plate provided with a vertical wall and a bottom wall extending in the horizontal direction from a lower end of the vertical wall. More specifically, a base end side of the projection lens unit is fixed to the vertical wall, the color synthesis optical system is arranged on the bottom wall, and the projection lens unit and the color synthesis optical system are integrated in a condition where the optical axes are aligned with each other through the vertical wall.
The head plate is fixed to the light guide by screwing the lower end part of the vertical wall to a lower light guide so that the modulated luminous flux is incident on the color synthesis optical system on the head plate from the modulation system in the light guide. In this projection display, it is strongly desired to integrate the system to facilitate the handling, and miniaturized to a minimum.
These projection displays have the following disadvantages.
(1) A cooling mechanism to cool a light source lamp, a power source unit and a circuit substrate which are stored in the external case is built in the above-mentioned projection display. The power source unit is cooled because the power source unit is provided with a primary side active filter, a power source, a ballast, etc., and the elements to be mounted thereon are the source of heat generation, a heat sink is fixed to each element to store the heat, and the heat sink is cooled.
However, the above-mentioned various kinds of optical systems must be mounted on the projection display to obtain the parallel luminous flux, and the ratio in volume of the optical system in the external case is increased. If the display is fully cooled, each component of the display can not be arranged too closely, raising a problem of limitation in miniaturization. Even if each component is arranged in a close contacting manner, there raises a problem that no efficient cooling can be performed.
(2) In the above-mentioned projection display, the head plate is connected to the light guide at the lower end part of the vertical wall, the distance between the connection part and the center of gravity of the projection lens unit is long, and the vertical wall can be deflected by the load of the projection lens unit to cause the deviation of the optical axis of the color synthesis optical system from the optical axis of the projection lens unit. Because the moment caused by the disturbance and impact at a part to which the projection lens unit is fixed generates the bending stress in a root part of the bottom wall and vertical wall of the head plate, the bending stress also has to deal with this problem. Thus, the vertical wall must be reinforced by providing a large number of ribs, raising a problem that the structure of the head plate is complicated.
SUMMARY OF THE INVENTION
The first object of the present invention is to provide a projection display capable of miniaturizing the display, and efficiently cooling the inside of the display in the projection display provided with an optical unit to optically process the luminous flux emitted from a light source lamp unit and project the magnified image on the projection surface by a projection lens unit, a power source unit to feed the power to the optical unit, and an external case to store said optical unit and said power source unit.
The second object of the present invention is to provide a projection display capable of simplifying the structure of a head plate in the above-mentioned projection display.
The first aspect of the present invention provides a projection display provided with an optical unit to optically process the luminous flux emitted from a light source lamp unit and project the magnified image on the projection surface by a projection lens unit, a power source unit to feed the power to the optical unit and a light source lamp unit, and an external case to store said optical unit and said power source unit, wherein in that an air inlet to suck the air for cooling from the outside of the display, and a discharge port to discharge the air inside the display outside are formed in said external case, one end part of said power source unit is arranged in the vicinity of said air inlet, an opening for suction to suck the air for cooling into said power source unit is provided in said one end part, an opening for discharge to discharge the air inside said power source unit is provided on the other end part of said power source unit, said light source lamp unit is arranged between the discharge port formed in said external case and an opening for discharge provided on the other end part of said power source unit, and the air to be discharged from the opening for discharge formed in the said other end part is distributed inside said light source lamp unit and utilized for the air for cooling said light source lamp.
In the first aspect of the invention, the power source unit is provided with the suction opening and the discharge opening, and the inside of the power source unit can be efficiently cooled independently from other parts, and the optical unit and the power source unit are closely arranged to miniaturize the display.
The above-mentioned opening for suction is preferably provided with a suction fan.
Because the air for cooling can be forcibly sucked inside the power source unit by the suction fan, the cooling efficiency inside the power source unit can be further improved.
The above-mentioned discharge port is preferably provided with a shielding means to cover the discharge port from the inside, and, for example, a shielding means of louver type which is formed by laminating a plurality of plate-shaped material having the length astride the discharge port is preferably adopted.
Because the shielding means is provided on the discharge port, no light is leaked from said discharge port even when the light source lamp unit is arranged in the vicinity of the discharge port, and convenience of the projection display is further improved.
Because the shielding means is formed of louver shape, the discharge from the discharge port is not shielded by the shielding means, and an appropriate discharge condition can be ensured.
Fur
Fujimori Motoyuki
Furuhata Mutsuya
Haba Shinji
Kuroda Akitoshi
Miyashita Kiyoshi
Dowling William
Oliff & Berridg,e PLC
Seiko Epson Corporation
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