Fujitsu Corporation

Munehiro Haraguchi

Hiroshi Murakami

Akira Yamamoto

Kazuhiro Takahara

Keizo Morita

Koji Yoshioka

Masafumi Itokazu

Masami Oda

Takayuki Hoshiya

Tadahisa Yamaguchi

Tetsuya Kobayashi

Hisashi Yamaguchi

Yoshiya Kaneko

Ken-ichi Nakabayashi

Mitsuharu Nakazawa

A capacitor electrode is formed simultaneously with drain bus lines. This capacitor electrode is electrically connected to the contact of two TFT's through the medium of a contact hole. Then, an interlayer insulating film is formed on the entire face and a black matrix of such light blocking metal film as Ti is formed on the interlayer insulating film so as to overlie the channel parts and the contacts of the TFT's and the capacitor electrode. The capacitor electrode, the interlayer insulating film formed thereon, and the black matrix jointly form a capacitor.

Liquid crystal display device and process for production thereof

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

A liquid-crystal display device includes a substrate with a pixel area including a plurality of scanning buses, a plurality of data buses intersecting therewith and pixel transistors and pixel electrodes formed at the intersections therebetween; a scanning driver for energizing these scanning buses; and a data driver for presenting these data buses with data signals. A checkout circuit equipped with a plurality of checkout transistors connected to the corresponding data buses or scanning buses; an input bus for applying prescribed checkout signals to the plurality of checkout transistors; and an output bus for picking up the signals from the plurality of checkout transistors.

Liquid-crystal display device having checkout circuit

An active-matrix LCD causes no cross-talk even if the capacitance between a given cell and adjacent data lines is large. The LCD has a liquid crystal panel which has data lines arranged in parallel with one another, scan lines arranged orthogonally to the data lines, and liquid crystal cells arranged at the intersections of the data and scan lines, respectively. Each of the cells has a cell electrode and a switching device that is arranged between and connected to the cell electrode and a corresponding one of the data lines. The conduction of the switching device is controlled in response to a scan pulse applied to a corresponding one of the scan lines. The LCD also has a data driver for applying data signals to the data lines, respectively, so that the data signals are written to corresponding ones of the cells, and a scan driver for applying the scan pulse sequentially to the scan lines. The data driver applies positive and negative signals that are opposite to each other with respect to a reference level, to each of the data lines within the period of the scan pulse, to zero an effective voltage applied to each data line. As a result, a voltage sustained by any cell to which data has been written is not affected by voltages successively applied to a data line to which the cell is connected and a data line to which the cell is capacitively connected.

Active-matrix liquid crystal display and method of driving same

In a driver circuit of direct drive matrix type LCD panel, a quantity of ON-STATE cells (or OFF-STATE cells) displayed on the just previous scan electrode is counted and a quantity of ON-STATE cells (or OFF-STATE cells) to be displayed on a present scan electrode is also counted. A compensation voltage is generated according to a predetermined relation based on a difference of the two above-counted quantities, and is superposed onto drive voltages of unselected scan electrodes or of each of data electrodes, in a polarity that an undesirable spike voltage induced on unselected cell voltage is cancelled, in synchronization with selection of the present scan electrode. The compensation voltage may be generated according to a digital difference of the two quantities or to a change in an analog voltage representing the counted quantity. The above-described relation of the compensation voltage versus the counted quantity difference may be proportional or may be given with a predetermined specific relation to meet the panel characteristics. The compensation voltage may be a flat voltage during the period for selecting the single scan electrode or may be of a spike waveform. Amplitude of this spike is determined by the above-described predetermined relation. An irregular panel brightness caused from spike voltages induced from data electrode voltage application is cancelled.

Method and apparatus for driving a liquid crystal display panel

Growing community of inventors

Kawasaki, Japan

Munehiro Haraguchi