Computer graphics processing and selective visual display system – Display driving control circuitry – Display power source
Patent
1993-04-28
1999-01-26
Lao, Lun-Yi
Computer graphics processing and selective visual display system
Display driving control circuitry
Display power source
345508, 264707, G09G 318
Patent
active
058643362
DESCRIPTION:
BRIEF SUMMARY
FIELD OF ART
The present invention relates to a liquid crystal display device in personal computers and more particularly relates to a liquid crystal display device equipped with an electric power consumption-reduction function, and providing stable display.
BACKGROUND OF THE INVENTION
Use of lap-top or notebook type personal computers or word-processors, etc., is being developed widely because of their portability. However, there is a common problem with compact type personal computers, that is, the electric power consumption. More specifically, these kinds of personal computers or word-processors, etc., use batteries as a portable power source, but these batteries allow the machine to operate normally for only two to five hours.
To deal with this, there are various measures taken for reducing the electric power consumption in this kind of personal computer.
One example for this measure is that if data is not input from the keyboard for a predetermined time, the operation of the CPU is stopped automatically and the display is turned off so as to reduce the electric power consumption. FIG. 1 shows a block diagram of a display device equipped with this kind of automatic display stop system together with a central processing unit (to be referred to as CPU hereinafter). Here, a display portion comprises a display controller or display image generating means 103 connected to a CPU 101 through a bus line 102, a first image display memory means 104 including a video memory (to be called a VRAM) and a liquid crystal display device (LCD) 107. A T1 measurement circuit 111 starts to measure a constant period of time T1 by means of a counter at the time an interrupt signal INTR 121 input into the CPU 101 changes from high level to low level. If the measurement circuit has finished counting the predetermined time from the count start without receiving a next interrupt signal, the circuit generates a count-up signal 113. With this, a display cut-off circuit 122, in accordance with the count-up signal 113 sent from the T1 measurement circuit 111, sets a signal 114 to high level to cut off the display. In other words, the measurement circuit 111 and the display cut-off circuit 122 constitute an electric power consumption mode switching means 108. Accordingly, the transmission of LCD data 115 and LCD drive signals 116 to a LCD is stopped. A display drive circuit 123, synchronized with the INTR 121 set to a high level after the display cut-off or in the course of counting, sets a signal 112 to high level, resets the counting and causes a signal 114 to be set to low level to operate the display. In FIG. 1, reference numerals 109 and 110 denote a power source and an external input means such as a keyboard, etc., respectively.
The conventional automatic display cut-off system, however, has a problem that if input has not been made for a predetermined period of time, the display is turned off, even when a user is looking at the display.
The present invention is to solve the problem and provide a personal computer or word-processor with which a user can take time to think, and which still prevents battery consumption.
DISCLOSURE OF THE INVENTION
In order to achieve the above object of the present invention, the present invention provides a liquid crystal display device having a technical structure as follows. That is, a display device is composed of a power source, a central processing means, a liquid crystal display means, a display image generating means, a first image display storage means, a display image data controlling means, an electric power consumption mode switching means, external input means and the like. In this arrangement the liquid crystal display device comprises the display image data controlling means which is equipped with a second image display storage means and which, in the normal electric power consumption mode, displays on the liquid crystal display means the display image data generated by the display image generating means via the first image display storage means and in the low electric power
REFERENCES:
patent: 4481382 (1984-11-01), Villa-Real
patent: 4483599 (1984-11-01), MacRae et al.
patent: 5059961 (1991-10-01), Cheng
patent: 5287298 (1994-02-01), Urushima
patent: 5327503 (1994-07-01), Kiyohara
patent: 5349688 (1994-09-01), Nguyen
patent: 5410714 (1995-04-01), Yorimoto et al.
patent: 5493685 (1996-02-01), Zenda
patent: 5515080 (1996-05-01), Nakamura et al.
<<Battery Powered Data Entry Unit>> by L.D. Foster I.B.M. Technical Disclosure Bulletin. vol. 15 No. 11 Apr. 1973 pp. 3437-3438.
Citizen Watch Co. Ltd.
Lao Lun-Yi
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