Canon Kabushiki Kaisha

Other

Junichiro Kanbe

Kazuharu Katagiri

Shigeru Shirai

Shinjiro Okada

Tsutomu Toyono

Keishi Saitoh

Kyosuke Ogawa

Tadaji Fukuda

Nagao Hosono

Yutaka Inaba

Yoichi Osato

Tohru Takahashi

Syuzo Kaneko

Teruo Misumi

Kazuo Yoshinaga

Shuzo Kaneko

Akihiro Mouri

Miki Tamura

Hideaki Takao

Masaru Kamio

Nobuyuki Sekimura

Tatsuo Murata

Yoshiki Kikuchi

Akira Tsuboyama

Yasuyuki Tamura

Shunji Nakamura

Yukio Hanyu

Osamu Taniguchi

Kozo Arao

Hideyuki Kawagishi

Masanobu Asaoka

Nobuyuki Miyake

Hideyuki Sugioka

Shinichi Nakamura

Takao Takiguchi

Hiroshi Inoue

Shigeru Ohno

Toru Takahashi

Takashi Moriyama

Isamu Shimizu

Takeshi Togano

Katsumi Kurematsu

Masahiko Enari

Yoshio Takasu

Eiichi Inoue

Yoshiyuki Osada

Yujiro Ando

Hatsuo Tajima

Masaki Kuribayashi

Masashi Suda

Hitoshi Shindo

Yukitoshi Ohkubo

Toshihiko Nakazawa

Shusei Tsukada

A layer of discotic liquid crystal having a molecular structure including a disk-shaped core and plural side chains connected to the core is disposed in contact with a substrate boundary provided with a homeotropic alignment power for aligning the side chains of the discotic liquid crystal molecules vertically to the boundary, whereby a uniform columnar structure vertical to the substrate of the discotic liquid crystal is formed. As a result, a discotic liquid crystal device having a stable homeotropic monodomain alignment can be formed from a wide scope of discotic liquid crystal materials.

Discotic liquid crystal device and alignment method therefor

A driving method for an optical modulation device is applicable to driving of an optical modulation device, e.g. a liquid crystal device having a matrix electrode arrangement comprising a group of scanning electrodes, a group of signal electrodes oppositely spaced from the group of scanning electrodes, and an optical modulation material (e.g. a liquid crystal) showing bistability with respect to an electric filed applied thereto disposed between the groups of scanning electrodes and signal electrodes. The driving method is featured by applying a voltage allowing the liquid crystal having bistability to be oriented to a first stable state (one optically stable state) between a selected scanning electrode of the group of scanning electrodes and a selected signal electrode of the group of signal electrodes, and by applying a voltage allowing the liquid crystal having bistability to be oriented to a second stable state (the other optically stable state) between the selected scanning electrodes and non-selected signal electrodes; or by applying a voltage allowing the optical modulation material having bistabity to be oriented to a first stable state between a selected scanning electrode and the group of signal electrodes, applying a voltage allowing the liquid crystal oriented to the first stable state to be oriented to a second stable state between the selected scanning electrode and a selected signal electrode, and applying a voltage set to a value between a threshold voltage -V.sub.th2 (for the second stable state) and a threshold voltage V.sub.th1 (for the first stable state) between non-selected scanning electrodes and the group of signal electrodes.

Method of driving optical modulation device

A liquid crystal apparatus comprises a liquid crystal device comprising a group of scanning electrodes and a group of signal electrodes intersecting each other to form an electrode matrix, and a chiral smectic liquid crystal disposed in a non-helical alignment state so as to form a picture element at each intersection of the scanning electrodes and the signal electrodes. Drive means are provided for: (a) applying a scanning selection signal and a scanning non-selection signal to the scanning electrodes, the scanning selection signal comprising a voltage of one polarity and a voltage of the other polarity, respectively with reference to a voltage level of the scanning nonselection signal, and being applied in a period for selecting one scanning electrode, (b) in a period of applying the voltage of one polarity, applying signals to the signal electrodes for causing one orientation state of the chiral smectic liquid crystal, so as to non-selectively erase the picture elements on a scanning electrode to which the scanning selection signal is applied, and (c) periodically applying the scanning selection signal to the scanning electrodes.

A driving method for an optical modulation device comprising matrix picture elements each formed at intersecting points of scanning lines and data lines between which a bistable optical modulation material represented by a ferroelectric liquid crsytal is interposed. The driving method comprises an erasure step of applying a voltage signal orienting the optical modulation material to the first stable state between the scanning and data lines, at all or a part of the matrix picture elements, and a writing step of sequentially applying a scanning selection signal to the scanning lines and applying an information orientation signal orienting the optical modulation material to the second stable state to the data lines in phase with the scanning selection signal.

Driving method for optical modulation device

An optical modulation device comprises scanning electrodes and signal electrodes disposed opposite to and intersecting with the signal electrodes, and an optical modulation material disposed between the electrodes, a pixel being formed at each intersection of the electrodes and showing a contrast depending on the polarity of a voltage applied thereto. The device is driven by a method comprising, in a writing period for writing in all or prescribed pixels among the pixels on a selected scanning electrode, a first phase for applying a voltage of one polarity having an amplitude exceeding a first threshold voltage of the optical modulation material to the all or prescribed pixels, and a second phase for applying a voltage of the other polarity having an amplitude exceeding a second threshold voltage of the optical modulation material to a selected pixel and applying a voltage not exceeding the threshold voltages of the optical modulation material to the other pixels, respectively among the all or prescribed pixels. The duration of a continually applied voltage of the same polarity applied to a pixel on a scanning electrode is 2.5 times the duration of the first phase in the writing period at the maximum.

A liquid crystal apparatus includes a liquid crystal device having a group of scanning lines and a group of signal lines intersecting each other to form a matrix of picture elements, and a chiral smectic liquid crystal disposed so as to form the picture elements. The device is driven by: (a) applying a scanning selection signal and a scanning non-selection signal to the scanning lines, the scanning selection signal comprising a voltage of one polarity and a voltage of the other polarity, respectively with reference to a voltage level of the scanning non-selection signal, (b) applying a data signal having a voltage determined according to an environmental temperature for causing one orientation state of the chiral smectic liquid crystal selectively to the signal lines in a period of applying the voltage of one polarity to a scanning line and applying a data signal having a voltage determined according to an environmental temperature for causing another orientation state of the chiral smectic liquid crystal selectively to the signal lines in a period of applying the voltage of the other polarity to the scanning line, and (c) periodically applying the scanning selection signal to the scanning lines.

A liquid crystal apparatus includes a liquid crystal device having a group of scanning lines and a group of signal lines intersecting each other to form a matrix of picture elements, and a chiral smectic liquid crystal disposed so as to form the picture elements. The device is driven by: (a) applying a scanning selection signal and a scanning non-selection signal to the scanning lines, (b) applying data signals having a predetermined voltage determined according to an environmental temperature and including a gradation data signal to the signal lines so as to provide a selected picture element at an intersection of a selected scanning line receiving the scanning selection signal and a selected signal electrode with a ratio between an area occupied with one orientation state and an area occupied by another orientation state, respectively of the chiral smectic liquid crystal, depending on given gradation data, and (c) periodically applying the scanning selection signal to the scanning lines.

A liquid crystal apparatus includes a liquid crystal device having a group of scanning electrodes and a group of signal electrodes intersecting each other to form an electrode matrix, and a chiral smectic liquid crystal having a threshold voltage varying depending on a voltage pulse width disposed so as to form a picture element at each intersection of the scanning electrodes and the signal electrodes. The electrodes are driven by (a) applying a scanning selection signal and a scanning non-selection signal to the scanning electrodes, (b) applying data signals to the signal electrodes so as to apply a voltage to a selected picture element at an intersection of a selected scanning electrode receiving the scanning selection signal and a selected signal electrode, the voltage applied to the selected picture element being at least two times a voltage applied to a non-selected picture element at an intersection of a non-selected scanning electrode receiving the scanning non-selection signal and a selected or non-selected signal electrode, (c) periodically applying the scanning selection signal to the scanning electrodes, and (d) setting a voltage level of the voltage according to a local environmental temperature.

A driving method for an optical modulation device is applicable to driving of an optical modulation device, e.g. a liquid crystal device having a matrix electrode arrangement comprising a group of scanning electrodes, a group of signal electrodes oppositely spaced from the group of scanning electrodes, and an optical modulation material (e.g. a liquid crystal) showing bistability with respect to an electric filed applied thereto disposed between the groups of scanning electrodes and signal electrodes. The driving method is featured by applying a voltage allowing the liquid crystal having bistability to be oriented to a first stable state (one optically stable state) between a selected scanning electrode of the group of scanning electrodes and a selected signal electrode of the group of signal electrodes, and by applying a voltage allowing the liquid crystal having bistability to be oriented to a second stable state (the other optically stable state) between the selected scanning electrodes and non-selected signal electrodes.

A driving method for an optical modulation device comprising matrix picture elements each formed at intersecting points of scanning lines and data lines between which a bistable optical modulation material represented by a ferroelectric liquid crystal is interposed. The driving method comprises an erasure step of applying a voltage signal orienting the optical modulation material to the first stable state between the scanning and data lines, at all or a part of the matrix picture elements, and a writing step of sequentially applying a scanning selection signal to the scanning lines and applying an information orientation signal orienting the optical modulation material to the second stable state to the data lines in phase with the scanning selection signal.

A liquid crystal device having a cell structure comprising a pair of base plates and a smectic liquid crystal having cholesteric phase at a higher temperature side; the ratio (P/d) of the spiral pitch of the cholesteric phase (P) to the spacing between the pair of base plates (d) is 0.5 or more.

Liquid crystal device

A liquid crystal device is constituted by (a) a pair of base plates each having an orientation control film thereon, and (b) a liquid crystal composition interposed between the base plates. The liquid crystal composition comprises a mixture including at least one liquid crystal compound which has a temperature range in which it shows chiral smectic phase and at least one optically active substance which does not have a temperature range in which it shows chiral smectic phase. The liquid crystal composition has a temperature range in which it shows cholesteric phase and is placed in chiral smectic phase which has been formed through cholesteric phase on temperature decrease. The liquid crystal composition comprises liquid crystal molecules having long axes forming a pre-tilt in the chiral smectic phase.

Liquid crystal device with composition containing optically active

Growing community of inventors

Yokohama, Japan

Junichiro Kanbe