Tohoku Pioneer Corporation

Pioneer Electronic Corporation

Other

Tohoku Pioneer Electronic Corporation

Takayoshi Yoshida

Masaki Murakata

Shinichi Ishizuka

Hideo Ochi

Masami Kimura

Katsuhiro Kanauchi

Teruichi Watanabe

Kazuhiko Sato

Shinobu Adachi

Yoichi Satake

Noriaki Kaneko

Shozaburo Sakaguchi

It is an object of the present invention to inhibit a collapse of a color balance possibly caused due to deterioration of self-emission elements when performing a color displaying by virtue of several different colors. A self-emission display apparatus comprises: a display element section consisting of self-emission elements; a monitor element section consisting of self-emission elements of different colors formed in the same manner as the self-emission elements of the display element section; a power supply circuit which supplies driving voltages to the display element section; monitor detecting units for detecting an operating state of the monitor element section; driving voltage control units which control driving voltages in accordance with a detected operating state; and a display control section for supplying display signal to the display element section. Further, the self-emission display apparatus has monitor control units which perform lighting controls of the foregoing different colors on the monitor element section, as well as a monitor load adjusting unit which adjusts a load state of each of the foregoing different colors in lighting control so as to maintain a color balance of the display element section.

Self-emission display apparatus and method of driving the same

In a light emitting display panel, a large number of light emitting display pixelsare arranged in a matrix pattern, and a monitoring element Ex is provided therein which can extract a voltage which corresponds to the forward voltage of EL elements Eon the display panel. By a signal from a current consumption detection sectionwhich detects current consumption in the light emitting display panel, a drive ratio control sectionperforms ON/OFF control of a transistor Trwhich is connected in series to the monitoring element Ex to control current provided from a constant current circuit. Thus, progression rates of agings of the monitoring element Ex and the EL elements Earranged in the display panel can be controlled to roughly coincide with each other, and a power loss generated in a light emission drive transistor Trin each pixelcan be restrained as much as possible.

Drive device of light emitting display panel

In a light emitting display device which is actively driven by TFTs, light emitting display pixels are driven efficiently. In a light emitting display panel, a large number of light emitting display pixelsare arranged in a matrix pattern and measuring pixelsare arranged forming a line along one dataline. A constant current is supplied from a constant current sourceto the measuring pixels, and the forward voltage VF of the EL element in the measuring pixelis obtained by a voltage detecting terminalThe value of the drive voltage supplied to the light emitting display pixelsis controlled based on the forward voltage VF. Thus, a drive TFT (Tr) constructing the light emitting display pixelcan drive an EL element Ein the state where a drop voltage (VD) of the degree by which a constant current characteristic can be ensured is ensured, and a power loss generated in the drive TFT can be effectively restrained.

Active drive type light emitting display device and drive control method thereof

Light-emitting elements disposed on a light-emitting display panel are driven by constant currents, and the forward direction voltages of the light-emitting elements are obtained by a sampling/holding circuit. Then, the voltage output from a drive voltage source composed of a DC-DC converter is controlled by the forward direction voltages obtained by the sampling/holding circuit. For example, in a case in which the light emission luminance of the light-emitting display panel is changed or in other case, a sampling and holding operation is executed by the sampling/holding circuit in response to a control signal from a sampling timing control circuit at intervals shorter than ordinary intervals. With this arrangement, when light emission luminance of a light-emitting display panel is changed, the gentle changing characteristics of the light emission luminance thereof can be improved.

Drive method of light-emitting display panel and organic EL display device

In a drive device for an active type light emitting display panel which can apply a reverse bias voltage to an EL element, in order to be able to compensate deterioration in light-emitting efficiency of the EL element accompanied by applying of the reverse bias voltage and the like, one pixelis composed of a controlling TFT (Tr), the driving TFT (Tr), a capacitor Cand the EL element ESwitching switches SWSWmutually enables a supplying state of a forward current to the EL element Eand an applying state of the reverse bias voltage to be selected. In one control form according to the present invention, when the applying state of the reverse bias voltage shifts to the supplying state of the forward current, by switching one switch first, the anode and cathode of the EL element Eare made to the same electrical potential to allow electrical charges to be discharged. Thus, charge of the forward current for a parasitic capacitance of the EL element Ecan be performed rapidly, and rising of the lighting operation of the EL element can be advanced.

Drive methods and drive devices for active type light emitting display panel

One pixel () is comprised of a controlling TFT (Tr), a TFT (Tr) functioning as a threshold voltage generating element, a TFT (Tr) functioning as a reset element, a driving TFT (Tr), a capacitor (C) holding the gate voltage of the driving TFT, a TFT (Tr) functioning as a current restraining means for being controlled so as to be OFF at a reset operation time, and an EL element (E). At the reset operation time in which a terminal voltage of the capacitor (C) is reset to a predetermined electrical potential, a current restraining means comprising the TFT (Tr) is controlled so as to prevent excess current due to an operation of the driving TFT (Tr) from being imparted to the EL element (E).

Active type light emitting display device

Light-emitting elements disposed on a light-emitting display panel are driven by constant currents, and the forward direction voltages of the light-emitting elements are obtained by a sampling/holding circuit. Then, the voltage output from a drive voltage source composed of a DC-DC converter is controlled by the forward direction voltages obtained by the sampling/holding circuit. For example, when the light-emitting display panel starts to be driven for light emission or when the light emission luminance of the light-emitting display panel that is being driven for light emission is to be increased, a control signal is sent from a light emission control circuit to a voltage forcibly changing circuit which supplies an output voltage increase command to the PWM circuit of the drive voltage source. With this arrangement, the rising-up property of the light-emitting display panel and the following property of luminance can be improved.

In an active-drive type pixel structure comprising at least TFT for control, TFT for drive, and a capacitor for charge retention, it can be easily inspected whether the functions of TFTs and the capacitor are normal or not. In an active-drive type pixel structure comprising TFT (Tr) for control, TFT (Tr) for drive, and a capacitor for charge retention, one terminal of a dummy load W for inspection is connected to a drain of the TFT for drive, and the other terminal of the load W is connected to a linefor inspection. By measuring an electric current Id obtained on the linefor inspection while changing a voltage supplied to a data line, it can be inspected whether the functions of TFTs and the capacitor are normal or not. The dummy load W is configured to be melted and cut by burning off the load W with a laser beam or by passing a predetermined electric current in the load W after completion of inspection.

Active-drive type pixel structure and inspection method therefor

Provided is a device for driving an active matrix type luminescent display panel, which can effectively apply a reverse bias voltage to a luminescent element via a drive TFT. A luminescent elementconstituting one pixelis light-up driven by a control TFTand a drive TFT. A serial circuit of the drive TFTand the luminescent elementis connected to a power source circuit via a switch Sand a switch S, whereby a state where a forward-directional current is supplied to the luminescent element or a state where a reverse bias voltage is applied to the luminescent element is selected. By using, as the control TFTand the drive TFT, TFT of the channel type of that is the same, it is possible to maintain the drive TFTto be in an 'on' state when having applied a reverse bias voltage to the luminescent element. By doing so, it becomes possible to effectively apply a reverse bias voltage to the luminescent element.

Device for driving luminescent display panel

In a drive unit for a luminescence display panel employing organic EL elements as light-emitting elements and capable of reducing power consumed by the display panel when a partial scan mode is selected, when the partial scan mode is selected by a scan mode switching mean, a control is performed so that the ratio of a drive period (D ), during which the light emission of the light-emitting elements is controlled, to a reset period (R ) set by a reset control means is increased as compared with a case in which the ordinary scan mode is selected. Thus, the momentary luminance of the light-emitting elements can be lowered by further reducing drive currents or drive voltages supplied to the respective light-emitting elements. Accordingly, it is possible to further reduce the power consumption of the luminescence display panel as well as to prevent the deterioration of the light-emitting elements, which contributes to extend the life of the light-emitting elements.

Drive unit for a luminescence display panel

A drive device for a light-emitting panel that is capable of adjusting the anode power source voltage to be applied to anode leads of the light-emitting panel to a suitable voltage value with low power consumption and in a reliable fashion. A prescribed anode lead of the anode leads of the light-emitting panel is designated as the anode lead that is to be the subject of detection. The voltage value on this anode lead which is the subject of detection is input as the forward voltage value only while display is being performed in accordance with prescribed information data to cause drive current to be supplied to at least the anode lead that is the subject of detection, and the anode power source voltage is adjusted in accordance with this forward voltage value.

Drive device for a light-emitting panel, and a portable terminal device including a light-emitting panel

There is specified an illumination drive line assigned to a capacitive luminescent element which is connected to a single scanning line and is to be illuminated in accordance with an input video signal during a scanning period. A first potential lower than an illumination threshold voltage of the capacitive luminescent element is applied to a single scanning line, and a second potential higher than the illumination threshold voltage is applied to the scanning lines other than the single scanning line. A drive current is supplied to the illumination drive line for forwardly applying a positive voltage higher than the illumination threshold voltage to the capacitive luminescent element to be illuminated. A third potential slightly lower than the illumination threshold voltage is applied to the drive lines other than the illumination drive line. During a reset period defined between scanning periods, the second potential is applied to all the scanning lines, and a fourth potential equal to the second potential is supplied to the drive line other than the non-reset drive line.

Luminescent display panel drive unit and drive method thereof

An apparatus for driving an electroluminescence device by supplying an alternating current to the electroluminescence device, the apparatus having: a direct voltage source; a constant voltage control device for generating a direct current having a constant voltage on the basis of an output of the direct voltage source; a constant current control device for generating a direct current having a constant current on the basis of the output of the direct voltage source; a selecting device for selecting either one of the direct current having the constant voltage and the direct current having the constant current; and a converting device for converting the selected direct current to the alternating current to be supplied to the electroluminescence device.

Apparatus for driving electroluminescence device and method of driving

The rotary magnetic head apparatus of this invention exhibits an optimum transfer characteristic similar to that in the conventional apparatuses even when the number of coil turns for the magnetic head is reduced to 10 or less. This is achieved by setting the number of secondary winding turns for the rotary transformer to 16 or less and by setting the number of primary winding turns for the rotary transformer in such a way that a product of a step-up ratio--defined as the number of secondary winding turns divided by the number of primary winding turns--and the number of coil turns will be around 50. This reduction in the number of turns of coil on the magnetic head, from 20 or 25 with the conventional apparatus to less than 10, results in a substantial reduction in the cost of magnetic head and therefore the rotary magnetic head apparatus.

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Yonezawa, Japan

Takayoshi Yoshida