Sharp Kabushiki Kaisha Corporation

Hiroshi Kishishita

Hisashi Uede

Toshihiro Ohba

Kinichi Isaka

Masashi Kawaguchi

Yoshihiro Endo

Etsuo Mizukami

Akio Inohara

Atsushi Sakamoto

Shigeyuki Harada

Hiroyuki Shimoyama

Noriaki Nakamura

Shuji Inada

Yoshiharu Kanatani

Yoshiyuki Kokuhata

Ikuo Ogawa

Kyoichi Yamamoto

Kazuo Shoji

Mikio Takeda

Yoshito Yamashita

Hiroyuki Kawabata

Takaaki Horita

Hisashi Ueda

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 method of manufacturing a thin film electroluminescent (EL) device in which an electron beam is directed to a pellet of a substance containing an additive agent, and the substance is evaporated and deposited on a substrate and a change per unit time of the growing deposit is monitored by a sensor, comprising the steps of (1) controlling energy of the electron beam in accordance with an output of the sensor during a first time interval for adjusting an evaporation rate of the substance to a specified rate, (2) maintaining the controlled energy of the electron beam constant during a second time interval, larger than the first time interval and alternatively repeating steps (1) and (2).

Method of manufacturing thin film EL device utilizing a shutter

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

There is provided a vapor deposition method for depositing a deposition material of an evaporation source on a substrate while a temperature of the substrate is uniformly kept. The method is implemented in a vapor deposition apparatus in which the evaporation source comprising the deposition material is opposed to the substrate in a vacuum chamber, a heater for heating the substrate is provided across the substrate from the evaporation source in the vacuum chamber and an equalizing plate is provided between the substrate and the heater. In addition, the equalizing plate is larger in size than the substrate and its thermal conductivity is 200 W.multidot.m.sup.-1 .multidot.K.sup.-1 or more and an infrared energy emissivity is 0.2 or more.

Vapor deposition method and apparatus for producing an EL thin film of

A display unit includes a thin film EL display panel, a scanning side switching circuit connected to a scanning side electrode, a data side switching circuit connected to a data side electrode, a scanning side drive circuit which outputs a high voltage pulse to the scanning side switching circuit and a data side drive circuit which outputs a signal voltage to the data side switching circuit. It further includes a device for decreasing a pulse width of a high voltage pulse supplied from the scanning side drive circuit to the scanning side switching circuit in accordance with an increase of the level of a high voltage generated by a high voltage power supply in the scanning side drive circuit.

Display unit having brightness control function

In a display device having a plurality of scanning-side electrodes arranged in one direction, a plurality of data-side electrodes arranged in a second direction intersection the first direction, and dielectric layers interposed therebetween, a modulated voltage the magnitude of which is varied according to the emission or non-emission of light is applied to the data-side electrodes, while applying a write voltage in line sequential fashion to the scanning-side electrodes, thereby performing the display control. In such a display device, the polarity of the voltage applied between the data-side electrode and the scanning-side electrode corresponding to the picture element to be driven for light emission is reversed one or more times during the period in which the write voltage is being applied to the scanning-side electrode. This serves to reduce the modulated voltage and the write voltage, thus contributing to the reduction in power consumption. Even when the modulated voltage or the write voltage is reduced, the desired brightness of emitted light can be obtained. In the case of not lowering the modulated voltage or the write voltage, it is possible to further enhance the brightness of emitted light.

Method and apparatus for driving a capacitive flat matrix display panel

A thin film EL display device is described which comprises a group of parallel scanning electrodes, a group of parallel data electrodes laid so as to extend perpendicular to the group of the scanning electrodes, and an EL layer disposed between the respective groups of the scanning and data electrodes. Each of the electrodes of at least one of the groups of the scanning and data electrodes which apply a writing voltage to the EL layer is connected with a driver circuit of high voltage breakdown characteristic having only a push-pull function or a pull-up and pull-down function. This driver circuit employs thyristors as switching elements.

Thin film el display device

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 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

A thin-film EL element is manufactured by forming a silicon nitride or silicon oxynitride film for a first dielectric layer by sputtering and a silicon nitride or silicon oxynitride film for a second dielectric layer by plasma chemical vapor deposition so that the element's resistance against moisture and mass productivity can be improved.

Method of manufacturing a thin-film electroluminescent display element

A thin film EL element has a glass substrate, a pair of electrode layers formed on this glass substrate, and an electroluminescent layer sandwiched between these electrode layers. The glass substrate is of non-alkali type and has volume resistivity of 10.sup.6 ohm-cm or greater at 600.degree. C., alkali content of 0.5 wt % or less, and strain point of 600.degree. C. or higher.

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Nara, Japan

Hiroshi Kishishita