Computer graphics processing and selective visual display system – Display driving control circuitry – Display power source
Reexamination Certificate
1998-11-12
2001-02-06
Liang, Regina (Department: 2774)
Computer graphics processing and selective visual display system
Display driving control circuitry
Display power source
C345S102000
Reexamination Certificate
active
06184875
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a display apparatus designed to operate in a power-saving fashion that is adapted to the input image signal.
2. Related Background Art
Known power-saving techniques for display apparatus include DPMS (Display Power Management Signaling) of the VESA (Video Electronics Standard Association). In projectors using image display devices, the light source lamp is normally turned off if no input signal has been received for a certain period of time.
In some display apparatus for video cam coders, the image being displayed is blacked out if no keys have been operated for a certain period of time.
As a result of the recent development of multi-media communication systems, there is a strong demand for display apparatus having a large and bright display screen and compatible with various input signals including NTSC signals and other television signals as well as image signals from computers. Metal halide lamps having a high output power and high pressure mercury lamps are being popularly used for large and bright display screens. Although power is reliably saved by turning off the light source lamp, it takes a considerable time for such a lamp to restore the proper brightness after it is turned on once again. Of the display apparatus compatible with various input signals, some meet the power-saving standards such as DPMS for signals from personal computers while the others do not. Additionally, no power-saving standards are currently provided for television signals and it is not possible for display apparatus to effectively meet the requirement of power-saving by a single operation such as turning off the light source lamp.
SUMMARY OF THE INVENTION
Therefore, a first object of the present invention is to provide a display apparatus with which a plurality of power-saving operations can selectively be used according to the input image signal.
A second object of the present invention is to provide a display apparatus make adapted to a power-saving operation that can be used when there is no incoming image signal and also when the input image signal has a frequency out of the frequency range with which the apparatus is adapted to display images.
A third object of the present invention is to provide a display apparatus that can selectively be driven in a plurality of power-saving modes depending on the resolution of the input image signal.
A fourth object of the present invention is to provide a display apparatus having a plurality of image input terminals to be selectively used in corresponding respective power-saving modes.
According to the invention, the above objects of the invention are achieved by providing a display apparatus comprising a CPU, an image display device, a light source for irradiating the image display device, a circuit for turning on/off the light source, a means for determining the resolution of the input image signal, a first switching means for turning on/off the power supply to the circuit components except the light source turning on/off circuit and a second switching means for turning on/off the power supply to the light source turning on/off circuit and adapted to operate in a first power-saving mode for opening the circuits by means of the first switching means after an appropriately selectable first predetermined period of time and also open the circuits by means of the second switching means after an appropriately selectable second predetermined period of time or in a second power-saving mode for opening the first and second switching means by a combination of the polarity of the input horizontal synchronizing signal and that of the input vertical synchronizing signal, the first power-saving mode and the second power-saving mode being able to be selectively used.
Preferably, the first power-saving mode is used when the absence of image signal is detected and when the input image signal has a frequency out of the frequency range with which the apparatus is adapted to display images.
Preferably, the first power-saving mode or the second power-saving mode can be selectively used for a plurality of input image signals with different resolutions.
Still preferably, a display apparatus according to the invention comprises a plurality of image signal input terminals and the first power-saving mode or the second power-saving mode can be selectively used for each of the input terminals.
With a display apparatus according to the invention, all the circuits except the CPU and the light source turning on/off circuit are opened by means of the first switching means after an appropriately selectable first predetermined period of time the light source turning on/off circuit is opened by means of the second switching means after an appropriately selectable second predetermined period of time when the first power-saving mode is selected, whereas the first and second switching means are opened by a combination of the polarity of the input horizontal synchronizing signal and that of the input vertical synchronizing signal when the second power-saving mode is selected.
REFERENCES:
patent: 5313225 (1994-05-01), Miyadera
patent: 6005559 (1999-12-01), Miyamoto
patent: 6020879 (2000-02-01), Nakabayashi
patent: 6078302 (2000-06-01), Suzuki
U.S. application No. 08/466,750, filed June 6, 1995.
U.S. application No. 08/655,893, filed May 31, 1996.
Canon Kabushiki Kaisha
Fitzpatrick ,Cella, Harper & Scinto
Liang Regina
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