Hitachi, Ltd.

Hitachi Video and Information System, Inc.

Kohji Takahashi

Hiroyuki Mano

Shigeyuki Nishitani

Naruhiko Kasai

Isao Takita

Tsutomu Furuhashi

Toshio Futami

Toshio Tanaka

Masaaki Kitajima

Masaki Mega

Takeshi Tanaka

Nobutake Konishi

Hideki Kamimaki

Kiyokazu Nishioka

Tatsuhiro Inuzuka

Jun-ichi Ohwada

Satoshi Konuma

Koichi Isaji

Ono Kikuo

Bunichi Fujimaki

A dot matrix display system for multiple-tone displays, including a display device in which pixels are arrayed in a matrix shape, an LC (liquid-crystal) drive signal generator which converts color display data into LC display data, an 8-level data driver which selects one of 8-level voltages in accordance with the LC display data and then delivers the selected voltage, and an 8-level voltage generator by which the 8-level applied LC voltages to be applied to the pixels are produced so as to substantially make uniform color differences between the respectively adjacent tones of the multiple-tone displays. Owing to the substantially uniform color differences between the respectively adjacent tones, multiple-tone displays which are uniformly seen by the human eye can be obtained.

Multiple-tone display system

A dot matrix display system for multiple-tone displays, including a display device in which pixels are arrayed in a matrix shape, an LC (liquid-crystal) drive signal generator which converts color display data into LC display data, an 8-level data driver which selects one of 8-level voltages in accordance with the LC display data and then delivers the selected voltage, and an 8-level applied LC voltage generator by which the 8-level applied LC voltages to be applied to the pixels are produced so as to substantially make uniform color differences between the respectively adjacent tones of the multiple-tone displays. Owing to the substantially uniform color differences between the respectively adjacent tones, the multiple-tone displays which are uniformly seen by the human eye can be realized.

A liquid crystal halftone display system including a tone generator which, for pixels having P tones of K tones (1&lE;P&lE;K), alternately outputs first N-bit tone display data and second N-bit tone display data in successive frames at one of a first phase and a second phase. Within a block of pixels, the tone generator alternately inverts the phase of the N-bit tone display data at successive first pixels having different ones of the P tones within the block of pixels beginning at a left side of the block of pixels, and alternately inverts the phase of the N-bit tone display data at successive pixels having a same one of the P tones within the block of pixels beginning at the left side of the block of pixels.

Liquid-crystal halftone display system

A dot matrix display system for multiple-tone displays, comprising a display device in which pixels are arrayed in a matrix shape, an LC (liquid-crystal) drive signal generator which converts color display data into LC display data, an 8-level data driver which selects one of 8-level voltages in accordance with the LC display data and then delivers the selected voltage, and an 8-level applied LC voltage generator by which the 8-level voltages to be applied to the pixels are produced so as to substantially make uniform color differences between the respectively adjacent tones of the multiple-tone displays. Owing to the substantially uniform color differences between the respectively adjacent tones, multiple-tone displays which are uniformly seen by the human eye can obtained.

A dot matrix display system for multiple-tone displays, including a display device in which pixels are arrayed in a matrix shape, an LC (liquid-crystal) drive signal generator which converts color display data into LC display data, an 8-level data driver which selects one of 8-level voltages in accordance with the LC display data and then delivers the selected voltage, and an 8-level applied LC voltage generator by which the 8-level voltages to be applied to the pixels are produced so as to substantially make uniform color differences between the respectively adjacent tones of the multiple-tone displays. Owing to the substantially uniform color differences between the respectively adjacent tones, multiple-tone displays which are uniformly seen. by the human eye can be obtained.

A dot matrix display system for multiple-tone displays, including a display device in which pixels are arrayed in a matrix shape, an LC (liquid-crystal) drive signal generator which converts color display data into LC display data, an 8-level data driver which selects one of 8-level voltages in accordance with the LC display data and then delivers the selected voltage, and an 8-level applied LC voltage generator by which the 8-level voltages to be applied to the pixels are produced so as to substantially make uniform color differences between the respectively adjacent tones of the multiple-tone displays. Owing to the substantially uniform color differences between the respectively adjacent tones, multiple-tone displays which are uniformly seen by the human eye can be obtained.

A liquid-crystal display system includes a data driver, a scan driver, a liquid-crystal panel, a line memory (204 in FIG. 2) in which input display data (101) for representing any of display-ON, display-OFF and halftone every pixel are stored for, at least, one line, and a halftone pattern generator (200) by which liquid-crystal display data (106) to be applied to the data driver are generated using the contents of the line memory and the input display data. The halftone pattern generator generates ON data in response to the input display data representing the display-ON of the pixel; it generates OFF data in response to the input display data representing the display-OFF of the pixel; and it generates the ON data and the OFF data alternately in successive frames as halftone data in response to the input display data representing the halftone display of the pixel, and it also compares the input display data of a pertinent line and those of a preceding line every line so as to invert a phase of changing-over the ON data and the OFF data in accordance with a result of the comparison. Since the number of ON pixels (or pixels for either of first and second data) for the halftone display is substantially equalized every frame, flickering can be reduced irrespective of display patterns.

A liquid-crystal display device of a simple matrix type is permitted to present a liquid-crystal display of good display quality free from nonuniformity in display brightness. A method of driving a liquid-crystal display device wherein voltages which correspond to potential differences between scanning voltages from a Y drive circuit and display voltages from an X drive circuit are applied to liquid-crystal cells at intersection points between scanning electrodes (Y electrodes) and data electrodes (X electrodes), thereby presenting a display conforming to display data comprises the steps of providing a correction time period for correcting the display voltage to be output from the X drive circuit at least once every scanning period of one line, and outputting a correction voltage at a voltage level which is intermediate between a voltage level in an ON-display state and a voltage level in an OFF-display state instead of the display voltage from the X drive circuit within the correction time period.

Method of and apparatus for driving liquid-crystal display device

An information processing equipment capable of multicolor display, comprising a CPU; a display memory which stores display information therein; a display unit which displays the display information in multiple colors selected from a predetermined number of colors to-be-developed; a display control circuit which controls transfer of information between the CPU and the display memory, and which regularly reads out the display information stored in the display memory and then sends the read-out display information to the display unit; a mode selector which selects one of at least two modes consisting of a first mode and a second mode, and which produces selection information, wherein the first mode causes the display unit to develop a smaller number of multiple colors and to operate at a lower frequency, while the second mode causes the display unit to develop a large number of multiple colors and to operate at a higher frequency; a clock signal generator which generates a plurality of clock signals of unequal frequencies; a clock selector circuit which receives the selection information to select the clock signal of the frequency corresponding to the mode indicated by the selection information, from among the plurality of clock signals delivered from the clock signal generator, and which delivers the selected clock signal to, at least, the display control circuit; and a maximum-number-of-colors selector which is provided in, for example, the display unit, and which receives the selection information to control the number of colors to-be-developed that are to be displayed by the display unit, to the number corresponding to the mode indicated by the selection information.

Information processing equipment capable of multicolor display

A half tone liquid crystal display circuit is disclosed including a voltage divider using as a reference voltage a voltage which is approximately determined on the basis of a point of intersection of the extensions of straight lines along the gradients of brightness-voltage characteristics corresponding to at least two observation angles vertically different with respect to a liquid crystal display panel having a TFT active matrix structure to generate driving voltages for the half tone displays associated with a voltage varied to correspond to the observation angles; and a correcting voltage waveform generator for generating a dynamic observation angle correcting voltage varied in association with a vertical scanning operation corresponding to the difference in the vertical observation angles of a liquid crystal display frame. The half tone driving voltages generated by the voltage divider from the dynamic observation angle correcting voltage are subjected to level modulations.

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Mobara, Japan

Kohji Takahashi