Semiconductor Energy Laboratory Co., Ltd.

Sharp Kabushiki Kaisha Corporation

Sharp Kabushiki Kaisha, Co., Ltd.

Munehiro Azami

Shou Nagao

Jun Koyama

Yoshifumi Tanada

Shunpei Yamazaki

Yutaka Shionoiri

Mitsuaki Osame

Tatsuya Arao

Kiyoshi Kato

Yukio Tanaka

Naoko Yano

Atsuo Isobe

Hiroshi Shibata

Yasushi Kubota

Hajime Washio

Chiho Kokubo

Aiko Shiga

Masaaki Hiroki

Tomoaki Atsumi

A pulse is inputted to TFTsandso that the TFTs would turn ON and then potential of a node a rises. When the potential of the node &#x3b1; reaches (VDD&#x2212;VthN), the node &#x3b1; became in a floating state. Accordingly, a TFTthen turns ON, and potential of an output node rises as a clock signal reaches the level H. On the other hand, potential of a gate electrode of the TFTfurther rises due to an operation of capacitanceas the potential of the output node rises, so that the potential of the output node would be higher than (VDD+VthN). Thus, the potential of the output node rises to VDD without voltage drop caused by a threshold of the TFT

Pulse output circuit, shift register and display device

A pulse is inputted to TFTsandso that the TFTs would turn ON and then potential of a node &#x3b1; rises. When the potential of the node &#x3b1; reaches (VDD&#x2212;VthN), the node &#x3b1; became in a floating state. Accordingly, a TFTthen turns ON, and potential of an output node rises as a clock signal reaches the level H. On the other hand, potential of a gate electrode of the TFTfurther rises due to an operation of capacitanceas the potential of the output node rises, so that the potential of the output node would be higher than (VDD+VthN). Thus, the potential of the output node rises to VDD without voltage drop caused by a threshold of the TFT

A circuit is provided which is constituted by TFTs of one conductivity type, and which is capable of outputting signals of a normal amplitude. When an input clock signal CKbecomes a high level, each of TFTs () is turned on to settle at a low level the potential at a signal output section (Out). A pulse is then input to a signal input section (In) and becomes high level. The gate potential of TFT () is increased to (VDD&#x2212;V thN) and the gate is floated. TFT () is thus turned on. Then CKbecomes low level and each of TFTs () is turned off. Simultaneously, CKbecomes high level and the potential at the signal output section is increased. Simultaneously, the potential at the gate of TFT () is increased to a level equal to or higher than (VDD+V thN) by the function of capacitor (), so that the high level appearing at the signal output section (Out) becomes equal to VDD. When SP becomes low level; CKbecomes low level; and CKbecomes high level, the potential at the signal output section (Out) becomes low level again.

Pulse output circuit, shift register, and display device

A light emitting device is provided which can prevent a change in gate voltage due to leakage or other causes and at the same time can prevent the aperture ratio from lowering. A capacitor storage is formed from a connection wiring line, an insulating film, and a capacitance wiring line. The connection wiring line is formed over a gate electrode and an active layer of a TFT of a pixel, and is connected to the active layer. The insulating film is formed on the connection wiring line. The capacitance wiring line is formed on the insulating film This structure enables the capacitor storage to overlap the TFT, thereby increasing the capacity of the capacitor storage while keeping the aperture ratio from lowering. Accordingly, a change in gate voltage due to leakage or other causes can be avoided to prevent a change in luminance of an OLED and flickering of screen in analog driving.

Light emitting device

A light emitting device is provided which can prevent a change in gate voltage due to leakage or other causes and at the same time can prevent the aperture ratio from lowering. A capacitor storage is formed from a connection wiring line, an insulating film, and a capacitance wiring line. The connection wiring line is formed over a gate electrode and an active layer of a TFT of a pixel, and is connected to the active layer. The insulating film is formed on the connection wiring line. The capacitance wiring line is formed on the insulating film. This structure enables the capacitor storage to overlap the TFT, thereby increasing the capacity of the capacitor storage while keeping the aperture ratio from lowering. Accordingly, a change in gate voltage due to leakage or other causes can be avoided to prevent a change in luminance of an OLED and flickering of screen in analog driving.

A novel driving method is provided in which source line inverting drive or dot inverting drive is performed for a case of driving a plurality of source lines by one D/A converter circuit in a source signal line driver circuit of an active matrix image display drive that corresponds to digital image signal input. In a first driving method of the present invention, two systems of grey-scale electric power supply lines are supplied to a source signal line driver circuit in order to obtain output having differing polarities from a D/A converter circuit, switches for connecting to the two systems of grey-scale electric power supply lines are prepared in each D/A converter circuit, the grey-scale electric power supply lines connected to each D/A converter circuit are switched in accordance with a control signal input to the switches, and source line inverting drive or dot inverting drive are performed.

Image display device and driving method thereof

There is provided a semiconductor device in which fabrication steps can be reduced by constructing a circuit using only TFTs of one conductivity type and in which a voltage amplitude of an output signal can be normally obtained. A capacitance () is provided between a gate and a source of a TFT () connected to an output node, and a circuit formed of TFTs () and () has a function to bring a node &#x3b1; into a floating state. When the node &#x3b1; is in the floating state, a potential of the node &#x3b1; is caused higher than VDD by using gate-source capacitance coupling of the TFT () through the capacitance (), thus an output signal having an amplitude of VDD&#x2212;GND can be normally obtained without causing amplitude attenuation due to the threshold value of the TFT.

Semiconductor device

A display device comprises a display panel composed of a pixel portion in which a plurality of TFTs are arranged in matrix, a source driver, and a gate driver, an image signal processing circuit for processing an image signal input from an external, and a control circuit for controlling the display panel and the image signal processing circuit. The image signal processing circuit corrects the image signal on the basis of a correction table. By feeding the display panel with the corrected image signal, the display device can provide a good quality image.

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Kanagawa, Japan

Munehiro Azami