Panasonic Liquid Crystal Display Co., Ltd.

Japan Display Inc.

Hitachi Displays, Ltd.

Hitachi, Ltd.

Hitachi Device Engineering Co., Ltd.

Other

Kazutaka Goto

Atsushi Hasegawa

Toshio Miyazawa

Iwao Takemoto

Masahiro Maki

Masashiro Maki

Hiroaki Asuma

A display driving circuit having a shift register is formed on the display panel. The shift register includes a first stage having first and second transistors and a second stage having a third and fourth transistor. A voltage of a control electrode of the first transistor is boosted by a voltage of a first pulse line changing from low to high. In an On state, the second transistor connects the control electrode of the first transistor and a constant voltage line. A voltage of a control electrode of the third transistor is boosted by a voltage of a second pulse line changing from low to high. In an On state, the fourth transistor connects the control electrode of the third transistor and a constant voltage line. The fourth transistor is switched on by a signal from the first stage.

Active matrix display device

A driving circuit for driving a display panel includes a dynamic ratioless shift register which is operated in a stable manner and can expand the degree of freedom of design. In the dynamic ratioless shift register which is provided with thin film transistors having semiconductor layers made of p-Si on a substrate surface, a node which becomes the floating state is connected to a fixed potential through a capacitance element.

A display device includes a dynamic ratioless shift register which is operated in a stable manner and can expand the degree of freedom of design. In the dynamic ratioless shift register which is provided with thin film transistors having semiconductor layers made of p-Si on a substrate surface, a node which becomes the floating state is connected to a fixed potential through a capacitance element.

The present invention provides a display device which can achieve the high breakdown voltage proof property, the enhancement of reliability or the expansion of the designing/process tolerance of transistors by the improvement of a circuit. A display device includes a plurality of pixels and a drive circuit which drives the plurality of pixels. The drive circuit includes a p-type first transistor which has a first electrode thereof connected to a first power source line to which a reference voltage V1 is applied, a p-type second transistor which has a first electrode thereof connected to a second electrode of the first transistor and a second electrode thereof connected to an output terminal thereof, an n-type third transistor which has a first electrode thereof connected to a second power source line to which a reference voltage V2 is applied, and an n-type fourth transistor which has a first electrode thereof connected to a second electrode of the third transistor and a second electrode thereof connected to an output terminal thereof. A first bias voltage Vcp is applied to a control electrode of the second transistor and a second bias voltage Vcn is applied to a control electrode of the fourth transistor. Further, a relationship V2&#x3c;Vcp&#x3c;V1 and a relationship V2&#x3c;Vcn&#x3c;V1 are satisfied.

Display device

A display device includes sub-pixels, video lines, a drive circuit and switch groups. The video lines are divided into plural blocks each composed of m video lines, m being an integer of 2 or more. The drive circuit outputs m gray scale voltages time-sequentially. Each of the switch groups corresponding to one of the blocks is composed of first to mth switches, receives the m gray scale voltages from the drive circuit, and then supplies them to the m video lines in a time-division multiplexed fashion. The mth switch is turned on last during a writing time for writing the m gray scale voltages into the sub-pixels, and Tq&#x3c;Tm, where Tm and Tq are times during which the mth switch and a qth switch of the first to (m&#x2212;1)th switches are turned on, respectively, and q is an integer of from 1 to (m&#x2212;1).

Display device employing a time-division-multiplexed driver

A display device includes a dynamic ratio less shift register which is operated in a stable manner and can expand the degree of freedom of design. In the dynamic ratio less shift register which is provided with thin film transistors having semiconductor layers made of p-Si on a substrate surface, a node which becomes the floating state is connected to a fixed potential through a capacitance element.

Growing community of inventors

Mobara, Japan

Kazutaka Goto