Sanyo Electric Co., Ltd.

Masatoshi Sato

Kazumasa Takai

Hitoshi Yasuda

Tomonori Matsumuro

The invention provides an organic EL display device usable for both negative and positive polarity video signals. The organic EL display device of the invention has a polarity switching circuit switching a polarity of a digital video signal. In a case where a display panel is made for a negative polarity video signal, when a negative digital video signal is inputted, this polarity switching circuit lets the negative polarity digital video signal pass therethrough without inverting its polarity. When a positive polarity digital video signal is inputted, this polarity switching circuit inverts a polarity of the positive polarity digital video signal and inverts and switches reference data for a white level and reference data for a black level in order to obtain an accurate inverted image. An output of the polarity switching circuit is converted into an analog video signal through a first D/A converter and outputted to the display panel.

Self-emission type display device

This invention provides a clock switching circuit that can switch clocks without causing a hazard or a distortion of a duty ratio of the clocks. The clock switching circuit of this invention includes a first synchronization circuit that synchronizes a clock selection signal with a first clock, a second synchronization circuit that synchronizes with a second clock the clock selection signal that has been synchronized with the first clock by the first synchronization circuit and a clock selection circuit that outputs '1', that is a high level, in synchronization with the clock selection signal that has been synchronized with the first clock by the first synchronization circuit and after that selects the second clock in synchronization with the clock selection signal that has been synchronized with the second clock by the second synchronization circuit.

Growing community of inventors

Gifu, Japan

Masatoshi Sato