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US5532713A Expired / Lapsed US ⏱️ 0.0 years remaining

Driving method for liquid crystal device

Assignee: Canon Inc
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Filing: 1994-04-18
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Granted: 1996-07-02
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Expires: 2014-04-18
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Abstract

Abstract A liquid crystal device of the type comprising a pair of oppositely disposed electrode plates having thereon a group of scanning lines and a group of data lines, respectively, and a liquid crystal disposed between the pair of electrode plates so as to form a pixel at each intersection of the scanning lines and data lines, is driven by a driving method including the steps of applying a scanning selection voltage waveform including a scanning selection signal to a scanning line within one scanning period, and applying a data signal waveform to data lines within the one scanning period. The data signal waveform is composed to include (i) a data signal period for a data signal synchronized with the scanning selection signal and providing a time-integrated voltage of zero applied to an associate pixel within the period and (ii) an AC signal period for an AC signal providing a time-integrated voltage of zero applied to the associated pixel within the AC signal period. As a result, a pixel on a selected scanning line written in an optical state, particularly a halftone state, is not affected by data signals applied for writing in pixels on a subsequently selected scanning line regardless of a relaxation time exhibited by the liquid crystal at the time of switching thereof.

Inventors

  • 👤 Shinjiro Okada
  • 👤 Yutaka Inaba
  • 👤 Kazunori Katakura

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-11-08 02:54
CPC Classifications
G; G09; G09G; G09G3/00; G09G3/20; G09G3/34; G09G3/36; G09G3/3611; G09G3/3622; G09G3/3629; G09G3/3637; G09G2310/00; G09G2310/06; G09G2310/061; G09G2320/00; G09G2320/02; G09G2320/0209; G09G3/2007; G09G3/2014; G09G3/207

Claims Analysis

Total Claims: 6
Claim 1
Independent Claim 224 words
A driving method for a liquid crystal device of the type comprising a pair of oppositely disposed electrode plates having thereon a group of scanning lines and a group of data lines, respectively, and a liquid crystal disposed between the pair of electrode plates so as to form a pixel at each intersection of the scanning lines and data lines, said driving method comprising: selecting a scanning line from among the scanning lines and applying a scanning selection signal to the selected scanning line at a scanning selection period (C) in one scanning period; and applying a data signal to a data line for an associated pixel on the selected scanning line, said data signal including a first signal in a data signal period (C) synchronized with the scanning selection period (C), a second signal, for compensating for the first signal, in a period (B), and an AC signal in an AC period (A), so that the first signal and the second signal provide a time-integrated voltage of zero to the associate pixel, and the AC signal also provides a time-integrated voltage of zero applied to the associated pixel; and said first signal having a waveform varying depending on gradation data for the associated pixel, and said AC signal having a waveform varying depending on the first signal applied subsequent to the AC signal.
Claim 2
Dependent Claim 224 words
A driving method for a liquid crystal device of the type comprising a pair of oppositely disposed electrode plates having thereon a group of scanning lines and a group of data lines, respectively, and a liquid crystal disposed between the pair of electrode plates so as to form a pixel at each intersection of the scanning lines and data lines, said driving method comprising: selecting a scanning line from among the scanning lines and applying a scanning selection signal to the selected scanning line at a scanning selection period (C) in one scanning period; and applying a data signal to a data line for an associated pixel on the selected scanning line, said data signal including a first signal in a data signal period (C) synchronized with the scanning selection period (C), a second signal, for compensating for the first signal, in a period (B), and an AC signal in an AC period (A), so that the first signal and the second signal provide a time-integrated voltage of zero to the associate pixel, and the AC signal also provides a time-integrated voltage of zero applied to the associated pixel; and said first signal having a waveform varying depending on gradation data for the associated pixel, and said AC signal having a waveform varying depending on the first signal applied subsequent to the AC signal.
Claim 3
Dependent Claim 25 words
A method according to claim 1, wherein the AC signal period (A) is prior to the data signal period (C) in the one scanning period.
Claim 4
Dependent Claim 31 words
A method according to claim 1, wherein a preceding voltage pulse in the AC signal has a polarity which is different from that of an initial pulse in the second signal.
Claim 5
Dependent Claim 15 words
A method according to claim 1, wherein each pixel has regions of mutually different thresholds.
Claim 6
Dependent Claim 16 words
A method according to claim 1, wherein said liquid crystal is a chiral smectic liquid crystal.

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