Kabushiki Kaisha Suwa Seikosha

Seiko Epson Kabushiki Kaisha

Satoru Yazawa

Minoru Hosokawa

Koichi Oguchi

Masayuki Ikeda

Mitsuo Nagata

Kenichi Endo

Yoichi Wakai

Shunji Banda

Hiroaki Ikejiri

Yoshiro Uchikawa

Masahide Isuda

The present invention provides, in an active matrix liquid crystal display device of the type including non-linear elements, for the application of an ON pulse-width modulation signal by the data line driving circuit at the rearward end of each selected period, during which the voltage corresponding to the duty-cycle of the selected signal is applied to the liquid crystal layer. The result is accurate reproduction of gray-scale images in the display under conditions of high duty-cycle driving. Further, cross-talk between columns caused by the data signal is controlled by supplying a signal voltage which eliminates the residual charges in the liquid crystal layer at the end of each selected period.

Liquid crystal video display device having pulse-width modulated 'ON'

A liquid crystal display device wherein display elements are arranged in a matrix display on a substrate and the display is driven in response to external display signals is provided. The display device includes a thin film layer having a rugged diffusing surface and an opposed transparent electrode plate spaced apart from the thin film layer. A guest-host liquid crystal material including a pleochroic dye is utilized. The thin film layer may be a metal film such as, aluminum, an aluminum alloy, silver or a silver alloy having a rugged surface for providing a diffused white surface formed by vaccum evaporation, sputtering, heat-treatment, recrystallization or etching.

Liquid crystal display device having diffusely reflective picture

A liquid crystal display device including an opaque reflective electrode on the lower plate of the device is provided. The surface of the electrode is a rugged surface wherein the average angle of inclination of an inclined plane passing through the inclined regions of the rugged surface is 30 degrees or less with respect to a horizontal plane coinciding with the surface of the lower plate. The area where the angle of inclination of the rugged portions is greater than 40 degrees occupies 30% or less of the surface area of the electrode. The average pitch of the rugged regions of the electrode surface is greater than 3 .mu.m and the depth of the rugged region is about 0.2 .mu.m on the average, but less than 5 .mu.m. The opaque electrode is formed from a metal having a reflectance of 80% or more with respect to incident light entering from a direction substantially vertical to the lower plate. The electrode is preferably an aluminum electrode and the rugged surface is obtained by first depositing an insulating layer of SiO.sub.2 by CVD and selectively etching the layer of SiO.sub.2 at an angle of between 0 degrees and 30 degrees to form a rugged surface. Alternatively, the SiO.sub.2 layer is treated by plasma spray and a resist is applied thereto. A widened viewing angle for a display utilizing a polarizer and a guest-host liquid crystal or a colored liquid crystal is obtained by utilizing the rugged electrode in accordance with the invention.

Liquid crystal display device

A matrix liquid crystal display circuit includes a selecting transistor connected to the picture element and a capacitor for each picture element of the matrix. The other picture element and capacitor terminals connect to common electrodes and the transistor gates in each row connect to a common electrode. In each column a common source line connects to the sources of the transistors and a signal sampling circuit periodically applies an image signal to the source line of each column in sequence. No amplification is used between the sampling circuit and the transistor sources. Metallic leads serve as the source lines, but other circuits and components are integrated on a common substrate.

Liquid crystal display system

A matrix liquid crystal display circuit operates on a level of AC voltage equal to the voltage required for DC drive. The circuit includes a selecting transistor connected to the picture element and a capacitor for each picture element of the matrix. The capacitor in each row connects to a common electrode and the transistor gates in each row connect to a common electrode. The voltage level of the common capacitor electrode is shifted periodically relative to a reference voltage in order to invert the image signal polarity across the picture element and produce an AC drive. Inverted image signals of similar voltage level are alternately sampled.

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Suwa, Japan

Satoru Yazawa