Fujitsu Corporation

Masami Oda

Kazuhiro Takahara

Tadahisa Yamaguchi

Akira Yamamoto

Hisashi Yamaguchi

Munehiro Haraguchi

Hiroshi Murakami

Fumitaka Asami

Masafumi Itokazu

Takayuki Hoshiya

Ken-ichi Nakabayashi

Tetsuo Aoki

Michiya Oura

A liquid crystal display has a liquid crystal layer, first and second electrodes, and a third electrode. The liquid crystal layer is inserted between the first and second electrodes to define liquid crystal cells. The third electrode is capacitively coupled with one of the first and second electrodes. A correction voltage for correcting distortion of a waveform for driving one of the first and second electrodes is applied to the third electrode, to keep an effective voltage applied to the liquid crystal cells unchanged and improve the display quality of the liquid crystal display. Therefore, the liquid crystal display of the present invention can correct distortion of a common voltage and prevent crosstalk.

Active matrix liquid crystal display and method of driving the same

In a driving device of an active matrix type liquid crystal display unit including a liquid crystal display panel, a scan driver, and a data driver, a data voltage controlling apparatus is provided to achieve digital multiple gray-scale levels with little flickering. The data voltage controlling apparatus supplies the data driver with a combination of two different data voltages picked up from a plurality of digital data voltages previously set. The combination of two different data voltages are, for example, a combination of different waveforms, a combination of negative level and positive level, and a combination of two different voltages having at least a voltage difference. Further, a division of T-V characteristics and an exchange of data voltages are carried out to reduce the flickering.

Apparatus for controlling data voltage of liquid crystal display unit to achieve multiple gray-scale

Disclosed is a liquid-crystal display having the capability of a tablet which offers high image quality and a high response speed. An active matrix type liquid-crystal display having the capability of a tablet comprises: an active matrix type liquid-crystal display composed of a device substrate having a plurality of scan electrodes, a plurality of data electrodes, a plurality of pixel electrodes, and a plurality of switching devices, and an opposed substrate holding a liquid crystal in cooperation with the device substrate; a voltage detector that when brought into contact with a display surface of the liquid-crystal display, detects pulses, which are applied consecutively to the scan electrodes and data electrodes, through electrostatic coupling between the detector and the scan electrodes or between the detector and the data electrodes and that outputs a detected signal; and a position detector for detecting a contact position of the detector on the basis of the detected signal. Herein, the device substrate is situated on the side of the observer of the display. The positions of data electrodes lying in the vicinity of a stylus are detected during a data electrode position detection period defined as a period during which no pulses are applied to scan electrodes. Positions of scan electrodes lying in the vicinity of the stylus are identified by detecting display scanning pulses that are applied consecutively to a plurality of scan electrodes in order to cause the switching devices to conduct consecutively during a display data writing period.

Liquid-crystal display having the capability of a tablet

A data driver circuit of TFT-LCD having a plurality of power source voltage terminals with different voltage levels, an output terminal for providing a voltage to the TFT-LCD, a plurality of analog switches with load resistances provided between one of the source voltage terminals and the output terminal and having a switching terminal, and a voltage selection circuit for transmitting an ON signal to a selected one or more of the respective switching terminals of the analog switches. When an individual analog switch is turned ON, the corresponding source voltage value is supplied to the output terminal of the driver circuit and when two or more analog switches are selectively turned on, a combination of the voltage levels of the respective source voltage is associated with those switches which are turned ON is produced as the driver circuit output voltage, thereby affording a greater number of gray levels as the driver circuit output voltage levels than the number of power source voltage levels.

Data driver circuit of liquid crystal display for achieving digital

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Kawasaki, Japan

Masami Oda