US4701025A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Liquid crystal display device with driving method to eliminate blur due to frequency dependence
Assignee: Hitachi Ltd
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Filing: 1985-08-19
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Granted: 1987-10-20
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Expires: 2005-08-19
Abstract
Abstract Between a liquid crystal module and a control circuit for controlling said liquid crystal module, there are provided that a counter circuit for counting down a timing signal given by said control circuit and an exclusive-OR circuit whose inputs are square wave pulses delivered from said counter circuit and square wave pulses given by said control circuit with a period of twice the frame period. The polarity of voltages applied to liquid crystal module is reversed by square wave pulses delivered from the exclusive-OR circuit with frequency higher than the frame frequency.
Inventors
- 👤 Shyusuke Endo
- 👤 Naofumi Aoyama
- 👤 Toshihiko Yabuuchi
- 👤 Toshiyuki Sakuma
- 👤 Kiyoshige Kinugawa
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 15:26
CPC Classifications
G; G09; G09G; G09G3/00; G09G3/20; G09G3/34; G09G3/36; G09G3/3611; G09G3/3614
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
123 words
A liquid crystal display device comprising: a liquid crystal module including a liquid crystal display panel having a plurality of liquid crystal picture elements arranged in a matrix form, and driving circuits for applying driving signals to signal electrodes and to scanning electrodes of the liquid crystal display panel, respectively; a control circuit for controlling the operation of the liquid crystal module; first means for dividing frequency of a timing signal given by the control circuit and producing a first signal of lower frequency; and second means for inverting the first signal of lower frequency once per frame period and generating a second signal to reverse the polarity of voltages applied to liquid crystal display elements with frequency higher than the frame frequency.
Claim 2
Dependent Claim
123 words
A liquid crystal display device comprising: a liquid crystal module including a liquid crystal display panel having a plurality of liquid crystal picture elements arranged in a matrix form, and driving circuits for applying driving signals to signal electrodes and to scanning electrodes of the liquid crystal display panel, respectively; a control circuit for controlling the operation of the liquid crystal module; first means for dividing frequency of a timing signal given by the control circuit and producing a first signal of lower frequency; and second means for inverting the first signal of lower frequency once per frame period and generating a second signal to reverse the polarity of voltages applied to liquid crystal display elements with frequency higher than the frame frequency.
Claim 3
Dependent Claim
17 words
A liquid crystal display device according to claim 1, wherein the first means is a counter circuit.
Claim 4
Dependent Claim
23 words
A liquid crystal display device according to claim 1, wherein the timing signal is a latch signal for latching information data for display.
Claim 5
Dependent Claim
45 words
A liquid crystal display device according to claim 1, wherein the second means is an exclusive-OR circuit which is supplied, as its input, with square wave pulses obtained from the first means and with square wave pulses with a period of twice the frame period.
References Cited (Backward Citations)
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Cited
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-10-19 | 1991-04-20 | 1991-10-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-10-19 | 1995-04-20 | 1995-10-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-10-19 | 1999-04-20 | 1999-10-20 | $7700.00 | Window Closed / Lapsed |