Sharp Kabushiki Kaisha Corporation

Sharp Corporation

Hisashi Uede

Toshihiro Ohba

Yasuhiko Inami

Yoshiharu Kanatani

Hiroshi Kishishita

Hiroshi Hamada

Keisaku Nonomura

Tomio Wada

Hiroshi Take

Masashi Kawaguchi

Hiroshi Nakauchi

Katubumi Koyanagi

Toshiaki Takamatsu

Kohzo Yano

Sadatoshi Takechi

Shigeyuki Harada

Kinichi Isaka

Hiroaki Kato

Yoshihiro Endo

Hiroshi Kinoshita

Fumiaki Funada

Masataka Matsuura

Tadanori Hishida

Kozo Yano

Shigehiro Minezaki

Akio Inohara

Atsushi Sakamoto

Shuji Inada

Yutaka Takafuji

Etsuo Mizukami

Keiichiro Shimizu

Kohhei Kishi

Yoshiyuki Kokuhata

Yoshihide Fujioka

Ikuo Ogawa

Yosihide Fujioka

Hisashi Yamaguchi

Shuichi Kozaki

Hiroshi Kuwagaki

Hiroyuki Shimoyama

Noriaki Nakamura

Syuichi Kozaki

Takeo Fujimoto

Kohei Kishi

Kazuo Shoji

Kiyoshi Sawae

Yoshito Yamashita

Kioichi Yamamoto

Heisaku Nonomura

Toshiaki Ishii

Takaaki Horita

Kinishi Isaka

Kyouichi Yamamoto

Yuji Ohno

In a display device such as a thin-film EL display device, etc. formed with a dielectric layer disposed between a plurality of scanning side electrodes and a plurality of data side electrodes in the direction for them intersecting to each other, a modulation voltage, varied according to gradation display data is applied to the data side electrodes, and a positive or negative writing voltage is applied to the scanning side electrodes in a line order for a gradation display different in brightness. Binary coded signals corresponding to each gradation of a gradation display are used as the gradation display data. The logical value of the binary coded signal is inverted according to the polarity of the writing voltage. Thus, a common gradation display can be performed from one binary coded signal for both the negative driving that applies a negative writing voltage and the positive driving that applies a positive writing voltage. As a result, by only by adding a data conversion circuit for inverting a binary coded signal, the function that converts the correspondence relation between the gradation to be displayed and the gradation display data depending on the negative driving or positive driving can be incorporated.

Method and apparatus for driving display device

A display device, such as thin film EL display device, is formed by interposing a dielectric layer between a plurality of scanning electrodes and a plurality of data electrodes which are arranged at right angles. Modulation voltage is varied in accordance to the display data, and is applied to the data electrodes. Further, a writing voltage is applied to the scanning electrodes in sequential line order, to thereby perform gradation display. Further, the writing voltage includes a ramp voltage, which varies with time. Thus, the peak of the current flowing through the luminescent layer of the picture element, as a current contributing to the luminescence, is suppressed to a low level. contributing to the luminescence, is suppressed to a low level. Accordingly, the energization period of the current is also elongated. Thus gradation display over multiple levels is made possible and a stable display of different gradation levels is enabled.

Method and apparatus for driving a display device

This invention relates to gradation display by a pulse width control method (PWM method) in every pixel in a capacitive display apparatus such as a liquid crystal display apparatus. The driving voltage applied to the electrodes is varied slowly, and the number of gradations of gradation display by the PWM method is increased. Since the capacitive display apparatus is used, for each electrode further from the drive circuit, the driving pulse is more influenced and its persisting duration is extended. As a result, even in identical gradation data, uneven colors may occur. The pulse width applied to the electrodes is gradually decreased as scanning of the electrodes sequentially occurs. Therefore, the brightness of the capacitive display apparatus may be made uniform over the entire screen surface.

Method and apparatus for driving capacitive display device

In accordance with the invention, gradation display is performed for each picture element in capacitive display apparatuses such as EL display apparatus by means of pulse width modulation. In doing so, pulse duration of the voltage applied to one group of electrodes among the a plurality of electrodes arranged in matrix is so set as to span over two scanning periods, during which another group of electrodes which are grouped into pairs each of two adjacent lines are scanned successively. This reduces the number of drive voltage charge and discharge cycles. Consequently power consumption of the display apparatus of PWM system can be controlled to a low level.

Method and apparatus for driving display apparatus

A method of driving a display device with a plurality of scanning side electrodes and a plurality of data side electrodes which are disposed in directions intersecting each other, and a dielectric layer interposed between the scanning side electrodes and the data side electrodes, and including steps of applying modulation voltages corresponding to display data to the data side electrodes, and also applying writing voltages of positive or negative polarity to the scanning side electrodes through line sequence, so as to cause picture elements composed of the dielectric layer to emit light. The driving method further includes steps of thinning out the display data, and applying a plurality of kinds of modulation voltages different in amplitude according to each frame, so as to cause the picture elements to effect gradation display of different brightness in multi-stages.

Method of driving a display device

A wiring circuit substrate comprises first circuit element means one one side of the substrate connected to electrode lines of X-Y matrix electrodes, respectively, and second circuit element means in the symmetrical position of the first circuit element means on the other side of the substrate connected to the electrode lines of the X-Y matrix electrodes, respectively, wherein each of leads of the first and the second circuit element means is connected to the output and input lines of the X-Y matrix electrodes via through holes, respectively. The first circuit element comprises integrated transisitors for driving the X-Y matrix electrodes. The second circuit element comprises integrated diodes for protecting an overcurrent in the X-Y matrix electrodes.

Symmetrical circuit arrangement for a X-Y matrix electrode

Electroluminescent display

A thin film EL display panel is composed of an EL layer placed between scanning electrodes and data side electrodes which are arranged at right angles to the scanning electrodes. A thin film EL display panel drive circuit includes a first and a second switching circuits connected to each of the scanning electrodes to apply voltages of negative and positive polarities, respectively, with respect to the voltage of the data side electrodes; and third and a fourth switching circuits connected to each of the data side electrodes to respectively charge and discharge the EL layer corresponding to the scanning electrode.

Thin film EL display panel drive circuit

A driving method of a thin film EL display unit and a driving circuit thereof comprising a thin film EL panel constituted by installing an EL layer between scanning-side electrodes and data-side electrodes and driver ICs which are connected respectively to the scanning-side electrodes and the data-side electrodes, wherein, on a drive which applies a write voltage positive to the data-side electrodes to the scanning-side electrodes, the scanning-side electrodes are raised once to a predetermined potential or higher, and thereafter the positive write voltage is applied thereto, and on a drive which applies a write voltage negative to the data-side electrodes to the scanning-side electrodes, the scanning-side electrodes are reduced once to a predetermined potential or lower, and thereafter the negative write voltage is applied thereto, which can reduce a maximum voltage applied to the scanning-side driver ICs.

Driving method of thin film EL display unit and driving circuit thereof

A thin-film EL display panel drive circuit capable of varying the drive voltage according to changes in the number of emitting picture elements.

A thin film electroluminescent (EL) display panel drive circuit includes first and second switching circuits for driving scanning electrodes of the panel in two fields, wherein odd numbered scanning electrodes are applied with a negative voltage polarity and even numbered scanning electrodes are provided with a positive voltage polarity in a first field, and the voltage polarities are reversed during the second field. Data signals are applied to data electrodes by a data electrode driver circuit which includes third and fourth switching circuits for providing selected data electrodes with a modulate voltage of a stepwise nature or ground, depending upon whether the selected data electrodes intersect with selected scanning electrodes having a negative or positive voltage polarity respectively. The stepwise modulation voltage is supplied by a control switching circuit which selectively supplies the third switching circuit with voltages of a first level, a second level and a floating level.

Thin film el display panel drive circuit

A driving method is described for thin film EL display devices having an EL layer interposed between scanning side electrodes and data side electrodes which are intersected to each other. The method comprises displaying frames formed by a line sequential drive in which voltage corresponding to display data is applied to the data side electrodes. Concurrently, write pulses which are negative and positive with respect to the data side electrodes are applied to the scanning side electrodes. Further the write pulses which are positive or negative with respect to the data side electrodes are applied to the scanning electrodes. The number of light emitting picture elements of the scanning side electrodes is previously detected from display data and the width of the write pulses, which are at least one of positive or negative is controlled in proportion to the number of the light emitting picture elements. Thus, the brightness of the light emitting picture elements is uniform due to the driving circuit thereof.

Driving method for thin film el display device and driving circuit

An aging drive method for a thin film EL panel includes the performing a preparatory step of short-circuiting all transparent electrodes by a first connecting line, short-circuiting every other metal electrodes by a second connecting line and short-circuiting the other metal electrodes by a third connecting line. Thereafter four fields are repeatedly periodically executed for a specified period of time to thereby cause all picture elements of the panel to luminesce for aging. Each of the four fields includes a first step of applying a first voltage across the first and second connecting lines and across the first and third connecting lines to charge all the picture elements. Further a second step is included of applying a second voltage across the second and third connecting lines while holding the transparent electrodes in a floating state. This causes luminescence of the picture elements of the metal electrodes short-circuited by the second or third connecting line, with the voltage resulting from the charge on the picture elements stored in the first step and with the second voltage. The four fields are different from one another in the combination of the polarities of the first and second voltages.

Method of driving thin film EL panel for aging

When driving a thin-film EL display panel having groups of two electrodes on opposing sides of a thin-film EL layer, a voltage is applied so that the polarity of the AC pulse applied to the intersection (picture element) of opposing electrodes is the reverse of the polarity of the AC pulse applied simultaneously or nearly simultaneously to adjacent or nearly adjacent picture elements. This drive method avoids flicker caused by differing luminance intensities resulting from alternating polarity in EL matrix-type displays.

Thin-film EL display panel drive

The preferred embodiment discloses a new thin-film EL display panel drive circuit using EL layers installed between the scan-side electrodes and the data-side electrodes aligned so as to allow them to cross one another, comprising: scan-side electrodes connected to the drain terminal of the N-ch high-voltage resistant driver having a grounded source terminal and also connected to the other drain terminal of the P-ch high-voltage resistant driver having a source terminal connected to the pull-up charge drive circuit and to the write drive circuit via the scan-side common bus line; and data-side electrodes connected to the drain terminal of the N-ch high-voltage resistant driver having a grounded source terminal and also having the anode common terminal connected to the cathode terminal of the diode array connected to the preliminary charge drive circuit via the data-side common bus line. By grounding the source terminal to the scan-side N-ch MOS ICs, some of the floating-output logic-circuit driving power sources and some of the logic signal transmission photo-couplers can be eliminated. This not only saves component elements conventionally needed for the P-N symmetric EL display panel drive circuits, but also securely suppresses noise interference, thus offering an indispensable technique giving an early and overall improvement over those thin-film EL display drive circuits thus far made available.

Thin-film EL display panel drive circuit

Growing community of inventors

Wakayama, Japan

Hisashi Uede