Sharp Kabushiki Kaisha Corporation

Shigeyuki Harada

Toshihiro Ohba

Hisashi Uede

Yoshiharu Kanatani

Hiroshi Kishishita

Atsushi Sakamoto

Yoshihide Fujioka

Kazuo Shoji

Kyoichi Yamamoto

Masashi Kawaguchi

Kinichi Isaka

Yosihide Fujioka

Makoto Kitahira

Noriko Temporin

Shohgo Yukawa

Atsushi Kiyohara

A discharge electrodefor generating ions and a high-voltage generating circuit unitthat supplies the discharge electrodewith a high voltage are housed in a housing. A discharge openingfor discharging the generated ions is formed in the housing. The housingis covered by an exterior case. The exterior caseis connected to the high-voltage generating circuit unitand functions as an induction electrode. A passage openingleading to the discharge openingis formed in the exterior case. An insulating sheetcovers the periphery of the passage openingin the exterior casefacing a space into which the ions are discharged so that the discharged ions do not attach to the exterior case. Decrease in the amount of discharged ions can be prevented while using a peripheral component of the discharge electrodeas the induction electrode.

Ion generating apparatus

A data side driving IC incorporates pull-up elements and pull-down elements to be applied with modulating voltages of &plus;&frac12;VM and &minus;&frac12;VM, respectively. A scanning side driving IC incorporates pull-up elements to be applied with a positive write voltage of &plus;VW from a positive voltage supply circuit, and pull-down elements to be applied with a negative write voltage of &minus;VW from a negative voltage supply circuit. Each data electrode is driven by a positive voltage of &plus;&frac12;VM or a negative voltage of &minus;&frac12;VM. Each scanning electrode is controlled so that it is applied with a positive write voltage of &plus;VW or a negative write voltage of &minus;VW or it assumes a ground potential or a floating potential. Since the data electrodes and the scanning electrodes can be driven with high symmetry of positive and negative polarities, the long-term reliability can be enhanced, while at the same time the peripheral circuitry can be simplified.

EL display apparatus

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 panel drive circuit capable of varying the drive voltage according to changes in the number of emitting picture elements.

Thin film EL display panel drive circuit

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

The present invention relates to a driving circuit of a thin film electroluminescent (EL) display, wherein a high withstand-voltage driver IC composed of a bi-directional switching element having push/pull function is connected with one or both of the scanning electrodes and the data electrodes of EL display, the bi-directional switching circuit for applying the writing voltage or the modulation voltage is applied with the pull up common line of each of the drivers IC and the pull down common line, a switch for extremely recovering, after the thin film EL element has emitted its light, the electric charge accumulated on the thin film EL display element, and a capacitor for accumulating the drawn out electric charge are disposed in the bi-directional switching circuit, and the modulation accumulation electric charge accumulated on the film EL display element after the light emission is accumulated on the capacitor, so that the modulation consumption power occupying the majority of the driving power without the damages to the conventional advantages may be reduced by 25% as compared with the conventional driving.

Driving circuit of thin membrane EL display apparatus

A drive circuit for a thin-film electroluminescent (EL) matrix display panel includes an odd side N-ch high voltage MOS driver, and an odd side P-ch high voltage MOS driver connected to odd number scanning electrodes of the thin-film electroluminescent (EL) matrix display panel. Even number scanning electrodes of the thin-film electroluminescent (EL) matrix display panel are connected to an even side N-ch high voltage MOS driver and an even side P-ch high voltage MOS driver. The four MOS drivers are effectively controlled to perform an alternating current driving of the thin-film electroluminescent (EL) matrix display panel. A source level switching circuit is connected to the odd side and even side N-ch high voltage MOS drivers so as to switch the source voltage in synchronization with the field driving of the thin-film electroluminescent (EL) matrix display panel.

Drive system for a thin-film el panel

A thin film EL display device wherein an EL layer is interposed between scanning side electrodes and data side electrodes which are arranged to cross one another. A data side driver IC, including switching elements for charging and discharging, is connected to the data side electrodes, and switching circuits for applying modulation voltage are connected to a pull-up common line of the data side driver IC. The switching circuits are provided with switches for removing the charge stored in the thin film EL device after the thin film EL device has emitted light and a capacitor for storing the removed charge, whereby the charge stored in the capacitor can be reused in the next light emission for the purpose of reducing power consumption.

Driving circuit for thin film EL display device

An EL (electroluminescent) panel driving system includes a display control circuit for producing, line by line, an image data. The image data of each line is defined by a combination of a HIGH level signal representing a spot illumination of the EL panel and a LOW level signal representing a non-illumination of a spot on the EL panel. The system further includes a pre-charge circuit and a pull-up charge circuit for providing a first range voltage to the EL panel at the beginning of each line scan operation to make the EL panel ready to illuminate, and a write-in circuit and a source level switching circuit for providing a second range voltage to the EL panel to permit the spot illumination of the EL panel in accordance with the HIGH level signals contained in the image data. These four circuits are turned on by four signals. The driving system also includes a detector that detects when no HIGH level signal are present in the image data of a line, an AND gate array for cutting off the four signals from the pre-charge circuit, pull-up circuit, write-in circuit, and source circuit, the four circuits are prevented from being actuated, thereby cutting off the power normally supplied during the blank line scanning to save power.

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Nara, Japan

Shigeyuki Harada