Optics: image projectors – Temperature control
Reexamination Certificate
2002-11-14
2004-03-02
Dowling, William (Department: 2851)
Optics: image projectors
Temperature control
C353S060000, C353S122000
Reexamination Certificate
active
06698898
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a display device and a liquid crystal projector.
2. Description of the Prior Art
As a light source lamp for backlight provided on a rear surface of a liquid crystal panel inside a liquid crystal projector, a metal halide lamp or an extra-high pressure mercury lamp is used. Therefore, the light source lamp for backlight significantly increases in temperature. Accordingly, the liquid crystal projector is provided with a suction fan for cooling for cooling the light source lamp for backlight.
When dust or dirt enters the liquid crystal projector, a shadow occurs when video is projected. Accordingly, the performance of the liquid crystal projector is degraded. In order to prevent the dust or dirt from entering the liquid crystal projector, therefore, an air filter is arranged on the suction side of the suction fan for cooling.
When the air filter is clogged, the suction capabilities of the suction fan for cooling are deteriorated, so that the temperature inside the liquid crystal projector rises.
In order to prevent the air filter from being clogged, the air filter may be periodically cleaned. In products comprising an air filter, for example, a cleaning machine, the air filter may be cleaned at the time point where it is felt that a suction force is weakened. However, a problem caused by the clogging of the air filter in the liquid crystal projector does not immediately appear as a normal symptom. Accordingly, the cleaning thereof is neglected in many cases.
When the liquid crystal projector continues to be used in a state where the air filter is clogged, the temperature inside the liquid crystal projector rises to reach a defined temperature, the power is shut off, entering a stand-by mode. Under such use circumstances that the temperature inside the liquid crystal projector reaches the defined temperature by the clogging of the air filter, the liquid crystal panel is degraded by the rise in the temperature to the time when the temperature inside the liquid crystal projector reaches the defined temperature.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a display device and a liquid crystal projector capable of informing a user of the timing at which an air filter arranged on the suction side of a suction fan for cooling should be cleaned in order to prevent the liquid crystal projector from being used in a state where the air filter is clogged.
In a display device comprising a suction fan for cooling and an air filter arranged on the suction side of the suction fan for cooling, a first display device according to the present invention is characterized by comprising means for calculating, in a case where the suction fan for cooling is driven, the integrated value of time periods during which the suction fan for cooling is driven; and means for displaying a warning message for causing a user to clean the air filter when the integrated value of the time periods during which the suction fan for cooling is driven is not less than a predetermined value.
In a display device comprising a suction fan for cooling and an air filter arranged on the suction side of the suction fan for cooling, a second display device according to the present invention is characterized by comprising a circuit for calculating, in a case where the suction fan for cooling is driven, the integrated value of time periods during which the suction fan for cooling is driven; and a circuit for displaying a warning message for causing a user to clean the air filter when the integrated value of the time periods during which the suction fan for cooling is driven is not less than a predetermined value.
In a liquid crystal projector comprising a suction fan for cooling and an air filter arranged on the suction side of the suction fan for cooling, a first liquid crystal projector according to the present invention is characterized by comprising means for calculating, in a case where the suction fan for cooling is driven, the integrated value of time periods during which the suction fan for cooling is driven; and means for displaying a warning message for causing a user to clean the air filter when the integrated value of the time periods during which the suction fan for cooling is driven is not less than a predetermined value.
In a liquid crystal projector comprising a suction fan for cooling and an air filter arranged on the suction side of the suction fan for cooling, a second liquid crystal projector according to the present invention is characterized by comprising a circuit for calculating, in a case where the suction fan for cooling is driven, the integrated value of time periods during which the suction fan for cooling is driven; and a circuit for displaying a warning message for causing a user to clean the air filter when the integrated value of the time periods during which the suction fan for cooling is driven is not less than a predetermined value.
The foregoing and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings.
REFERENCES:
patent: 6254238 (2001-07-01), Takamatsu
patent: 6450646 (2002-09-01), Ono et al.
Nakamura Hisashi
Okino Toshiyuki
Terami Kouji
Dowling William
Rader & Fishman & Grauer, PLLC
Sanyo Electric Co,. Ltd.
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