Nec Corporation

Nippon Electric Co., Ltd.

Hiroshi Hada

Tsutomu Hirayama

Tsunekiyo Iwakawa

Kazunori Nishida

Tadashi Nakamura

Susumu Ohi

Muneo Maruyama

Masatake Baba

Tae Miyahara

Toshiro Wakabayashi

Toshihiko Ueno

Shigeki Okutani

Yoshihisa Hosono

An active matrix liquid display system where two scanning lines are successively selected within one horizontal scanning period, by which display voltages are written on pixels lined up in a horizontal direction, and the voltage supplied to a signal line when an even number display pixel is selected and the voltage supplied to a signal line when an odd number display pixel is selected are switched according to a gradation voltage generated from a gradation power source. Accordingly, when there is implemented a dot inversion drive in the active matrix liquid display system where there are less number of signal line drive circuits, and when a former stage pixel is subjected to modulation due to interpixel parasitic capacitance, it is possible to equalize an electric voltage of the former stage pixel being modulated as a latter stage pixel is being written with an electric voltage of the latter stage pixel, owing to revision of a gradation voltage of the former stage pixel.

Active-matrix display system with less signal line drive circuits

In a TN LCD, a prism lens film and a wave lens film are disposed on the incoming and outgoing sides of a liquid crystal panel, respectively, to obtain an image wide in visual angle and good in its quality. Thus, outgoing light having a sharp directivity, can be obtained from light emitted from a surface illuminant and having a gradually varying directional property by the prism lens film. Further, with a louver film provided in front of the prism lens film, all the light traveling in the diagonal direction can be cut off so that substantially parallel light enter the liquid crystal panel. Since the light in which a variation in retardation is next to nothing, is diffused by the wave lens film, a wide visual-angle representation free of a dependence on the visual angle can be obtained. In order to prevent the image from being turned white due to the reflection of external light and obtain an image of satisfactory quality, which is high in contrast ratio, the front surface of the wave lens film is coated with a multilayer film. Further, both surfaces of the liquid crystal panel and the wave lens film, which are opposed to each other, are coated with multilayer films. Furthermore, an improvement in performance can be carried out by providing a louver film between the prism lens film and the liquid crystal panel.

Transmissive liquid crystal display having prism lens film for light

A method for displaying an image with multilevel brightness by using an image display device in which an image is displayed by sequentially activating scan lines one by one, and one complete display image is formed by at least a plurality of continuous frames or fields. A brightness of the whole of the display screen is changed in units of one frame or field, so that each display pixel can have brightness levels which are respectively defined by combinations of brightness levels given by an input display data and brightness levels of the whole of the display screen.

Multilevel image display method and system

The invention provides voltage potential differences for selectively discharging cells in a plasma display device, with greater brightness and reduced power consumption. The plasma display device has orthogonally related electrodes sealed in an atmosphere of neon gas. When a predetermined potential is applied between two intersecting electrodes, the neon gas glows at the intersection. The predetermined potential is achieved by applying two pulse trains which have opposite phases and therefore oppositely going voltage polarities. The difference in the oppositely going peak voltages of the two pulse trains provides a firing potential at the selected intersection. To decrease the voltage causing an erroneous discharge, a short period of an extinction mode is introduced before an address mode. In another embodiment, to reduce power consumption, the cell at the intersection is fired at a high potential during an address mode and thereafter held in a glowing state by a greatly reduced voltage. Another embodiment produces a similar result by changing the frequency of driving pulses in the firing and the holding modes.

Plasma display apparatus

The invention provides voltage potential differences for selectively discharging cells in a plasma display device, with greater brightness and reduced power consumption. The plasma display device has orthogonally related electrodes sealed in an atmosphere of neon gas. When a predetermined potential is applied between two intersecting electrodes, the neon gas glows at the intersection. The predetermined potential is achieved by applying two pulse trains which have opposite phases and therefore oppositely going voltage polarities. The difference in the oppositely going peak voltages of the two pulse trains provides a firing potential at the selected intersection. To reduce power consumption, the cell at the intersection is fired at a high potential during an address mode and thereafter held in a glowing state by a greatly reduced voltage. Another embodiment produces a similar result by changing the frequency of driving pulses in the firing and the holding modes.

A pulse signal transistor circuit with an improved turn-off characteristic comprises a first pulse signal source connected to the base electrode of the transistor and a second pulse signal source connected to the emitter electrode of the transistor. The first and second pulse signals have the opposite phases, thereby enhancing the extinction of minority carriers stored in the base region of the transistor.

Pulse signal control circuits with improved turn-off characteristic

A first diode having a polarity opposite to the diode characteristic between the emitter and base electrodes is connected across these electrodes of a first transistor, a resistor having a high resistance is connected between the collector and the base electrodes of the first transistor and a first source of high reference potential is connected to the collector electrode. The collector electrode of a second transistor is connected to the base electrode of the first transistor and to a second diode and the emitter electrode of the second transistor is connected to a second source of low reference potential. A high frequency pulse signal is applied to the collector electrode of the second transistor through the second diode, and a pulse data signal containing a high frequency pulse signal synchronous with the first mentioned high frequency pulse is applied to the base electrode of the second transistor thereby producing an amplified pulse data signal containing a high frequency pulse signal corresponding to a data input signal on the emitter electrode of the first transistor.

Pulse signal control circuits

A plasma display system in which display cells in an external electrode type plasma display panel are forcibly fired at a predetermined period regardless of given display signals, which can greatly improve turn-on characteristics of a display without adversely affecting the display function.

Plasma display system

A circuit for driving one electrode group of a gas discharge display panel includes a plurality of PNP transistors and NPN transistors. The emitter electrodes of the PNP transistors are connected to a positive voltage source and the emitter electrodes of the NPN transistors are connected to ground. Diode means are connected between the collector electrodes of the PNP transistors and those of the NPN transistors across matrix points formed at the intersections of a first plurality of conductors connected respectively to the collector electrodes of the PNP transistors and a second plurality of conductors connected respectively to the collector electrodes of the NPN transistors. The individual electrodes of one electrode group of the gas discharge panel are connected to the diode means. The circuit also includes a first plurality of diodes and a second plurality of diodes connected to the first plurality of conductors and the second plurality of conductors, respectively.

Driving circuit for a gas discharge display panel

A plasma display panel comprising a plurality of electrodes between a pair of dielectric plates that form gas discharge cells is provided with an additional electrode on one of the dielectric plates to form additional gas discharge cells of an effective discharge area larger than the discharge areas of the cells for use in exhibiting a desired display. The effective discharge area may be enlarged either by the use of a wide additional electrode or by application to the additional electrode of a high-frequency voltage whose peak-to-peak value is higher than that of the high-frequency voltages supplied selectively across the display exhibiting cells.

Plasma display panel having additional discharge cells of a larger

A circuit for driving one electrode group of a gas discharge display panel includes a plurality of PNP transistors and NPN transistors. The emitter electrodes of the PNP transistors are connected to a positive voltage source and the emitter electrodes of the NPN transistors are connected to ground. Diode means are connected between the collector electrodes of the PNP transistors and those of the NPN transistors across matrix points formed at the intersections of a first plurality of conductors connected respectively to the collector electrodes of the PNP transistors and a second plurality of conductors connected respectively to the collector electrodes of the NPN transistors. The individual electrodes of the one electrode group of the gas discharge tube are connected to the diode means and grounded through capacitors, which may be included in the gas discharge display panel.

Growing community of inventors

Tokyo, Japan

Hiroshi Hada