Computer graphics processing and selective visual display system – Plural physical display element control system – Display elements arranged in matrix
Reexamination Certificate
1997-05-01
2001-06-05
Saras, Steven (Department: 2675)
Computer graphics processing and selective visual display system
Plural physical display element control system
Display elements arranged in matrix
C345S088000
Reexamination Certificate
active
06243067
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a liquid crystal projector having a light source, a liquid crystal panel, and a projector lens.
An example of a conventional liquid crystal projector is shown in
FIG. 9
from Japanese Laid-open Patent Publication NO. 5-313115.
FIG. 9
is a structural diagram depicting the basic concept of a liquid crystal projector. In
FIG. 9
, a power source
10
of a liquid crystal projector main body supplies electric power to a light source driving power source
20
. The light source driving power source
20
converts the electric power supplied from the power source
10
into a state optimum for driving a light source
30
, and supplies the electric power to the light source
30
. As the light source
30
, a halogen lamp or the like is used. A condenser lens
40
is used to condense the rays of light from the light
30
, and to transform the rays into parallel light. The transformed rays of light are fed into a liquid crystal panel
50
, which functions as an image forming unit to form an image. The image is later magnified by a projector lens
60
, and a magnified image is projected on a screen
70
.
In the conventional constitution, as shown in
FIG. 9
, since the light efficiency of the light source is extremely low, the image becomes dark when a large image is projected. Accordingly, by using a plurality of light sources, a method for producing a brightness sensation of a large image hag been proposed. However, the problem in this case is that the electric power consumed by one light source is as much as hundreds of watts. Therefore, when plural light sources are lit up or put out simultaneously, the stress to load fluctuations of the power source feeding electric power to the light sources is large, which may lead to breakdown of power source or the like.
SUMMARY OF THE INVENTION
The liquid crystal projector of the present invention comprises plural light sources, a liquid crystal panel for modulating the light emitted from the lighting light source out of the plural light sources, corresponding to image information, and a projector lens for projecting a light image modulated by the liquid crystal panel. Each one of the plural light sources emits light sequentially in time. The emitted light is modulated by the liquid crystal panel, and a light image is produced. The light image is projected by a projector lens. The liquid crystal panel is a valve for controlling the transmission of light.
With this arrangement, the fluctuation width of the load of the power source supplying electric power to the light source is decreased, the occurrence of troubles, such as a breakdown of the power source or light source is prevented, and a bright image is obtained.
In the present invention, preferably, when a switch of a power source is switched on, each one of the plural light sources starts emitting light sequentially delayed in time. Such a constitution has the advantage of a providing a bright image without fluctuations in power and breakdowns of the power and light sources.
The liquid crystal projector, according to the present invention further comprises, plural light-source-driving-power-sources connected to the plural light sources individually, and light-source-lighting-control-means for sending a light-source-lighting-control-signal to the plural light-source-driving-power-sources, whereby each one of the plural light sources lights up or emits light sequentially by means of the light-source-lighting-control-means.
Another liquid crystal projector, according to the present invention comprises, plural light sources, a liquid crystal panel for modulating the light emitted from the plural light sources corresponding to image information, and a projector lens for projecting a light image modulated by the liquid crystal panel. At least two of the plural light sources emits light alternately. This arrangement provides the advantage of improving the life of the light sources.
In the present invention, the light-source-lighting-control-means is a delay circuit, and each one of the plural light sources lights up sequentially by the delay circuit, which provides time controlled signals to each of the light-source-driving-power-sources.
As a variation, the light-source-lighting-control-means is a counter circuit that provides time controlled signals to each of the light-source-driving-power-sources.
In another variation, the light-source-lighting-control-means is a programmed microcomputer that provides time controlled signals to each of the light-source-driving-power-sources.
The present invention provides the advantages of decreasing the fluctuation width of the load of the power source for supplying electric power up to the light source, preventing the occurrence of troubles such as the breakdown of the power source or light source, and results in a bright image.
The invention itself, together with further objects and attendant advantages, will best be understood by reference to the following detailed description taken in conjunction with the accompanying figures.
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patent: 4739396 (1988-04-01), Hyatt
patent: 4907862 (1990-03-01), Suntola
patent: 5121233 (1992-06-01), Spencer et al.
patent: 5337068 (1994-08-01), Stewart et al.
patent: 5392140 (1995-02-01), Ezra et al.
patent: 5491525 (1996-02-01), Yamasaki et al.
patent: 5495150 (1996-02-01), Zawislak et al.
patent: 5502490 (1996-03-01), Takanashi et al.
patent: 5796376 (1998-08-01), Banks
patent: 5798864 (1998-08-01), Sekiguchi
patent: 5-313115 (1993-11-01), None
patent: 6-60833 (1994-08-01), None
Mukai Kazuo
Noguchi Toshiyuki
Alphonse Fritz
Matsushita Electric - Industrial Co., Ltd.
McDermott & Will & Emery
Saras Steven
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