Koninklijke Philips Corporation N.v.

Hosiden Corporation

Nippon Telegraph and Telephone Corporation

Takeo Kamiya

Masaru Yasui

Yukio Takahashi

Hidetoshi Watanabe

Tadaaki Masumori

Tadamichi Kawada

Tadao Nakamura

Masanori Hosomichi

The device has an LCD panel , a digital circuit and an analog circuit which generate display signals to be supplied to the LCD panel , and has functions of normal mode and stand-by mode in a status where electric power is supplied from a power source . In the normal mode, a multivalued display signal which can represent gradation levels is generated and supplied to the LCD panel , while in the stand-by mode, a binary display signal which does not represent gradation levels is generated and supplied to the LCD panel

LCD device

The liquid crystal driving circuit device has AC generating means ( ) for generating an alternating current component of a drive signal, a capacitive element ( ) with one terminal connected with said AC generating means, current limitation means ( ) with one terminal connected with the other terminal of the capacitive element ( ), and DC generating means ( ), for generating a direct current component of the drive signal, said DC generating means having an output connected to another terminal of the current limitation means ( ). The capacitive element ( ) eliminates the direct current component of an output signal from the AC generating means ( ), and the current limitation means ( ) limits a current caused by a voltage difference between a voltage at the other terminal of the capacitive element ( ) and a voltage at the output. Further, an amplitude value of the alternating current component from the AC generating means and an amplitude of the alternating current component of a signal from the DC generating means ( ) are approximately the same.

LCD drive circuit

Liquid crystal display AC-drive method and liquid crystal display using

An input analog image signal is sampled by first and second A/D converters, using first and second sampling clocks of the same period, to obtain digital gradation data. In the case of a double definition display mode, the first and second sampling clocks are made 180.degree. out of phase with each other and the output of the first A/D converter is delayed for one-half period, by which its timing is brought into agreement with that of the output of the second A/D converter, thus obtaining a pair of digital gradation data. In the case of a standard definition display mode, the first and second sampling clocks of the same phase are used to obtain the outputs of the first and second A/D converters as a pair of digital gradation data. The pair of digital gradation data Da and Db is converted by a signal processing part into a pair of analog gradation data Aa and Ab, which is subjected to a serial-to-parallel conversion by a source driver to be supplied in parallel to data lines. In the double definition display mode the gate driver sequentially drives odd-numbered row lines in odd-numbered frames and even-numbered row lines in even-numbered frames. In the standard definition display mode every two adjacent row lines are simultaneously driven in a sequential order.

Liquid crystal display device capable of selecting display definition

Growing community of inventors

Kobe, Japan

Takeo Kamiya