Patent US5048934A successfully refreshed from Google Patents.
US5048934A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of driving ferroelectric liquid crystal without timing conversion circuitry
Assignee: Sharp Corp
•
Filing: 1989-10-25
•
Granted: 1991-09-17
•
Expires: 2009-10-25
Abstract
Abstract In a method of driving a ferroelectric liquid crystal display panel, a non-selection voltage B is continuously applied to a scanning electrode L i from the time at which the selection voltage A is applied to the scanning voltage L i to the time at which the selection voltage A is again applied to the scanning electrode L i . Further, succeeding erasing voltage H is applied to the scanning electrode L i at the time N×t 0 before the application of the selection voltage A. Thereby, approximately the same effect as realized by the application of voltage -V g for P×t 0 can be provided on a pixel A ij . This occurs irrespective of whether a bright voltage D or a dark voltage E is applied to a signal electrode S j . Thus, the pixel A ij can be set to the dark memory state. At the time Q×t 0 before the application of the succeeding erasing voltage H to the scanning electrode L i , a compensation voltage G is applied. Thus, driving with no DC component left on the pixel A ij can be realized.
Inventors
- 👤 Takaji Numao
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 09:42
CPC Classifications
G; G09; G09G; G09G3/00; G09G3/20; G09G3/34; G09G3/36; G09G3/3611; G09G3/3622; G09G3/3629; G09G2310/00; G09G2310/06
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
269 words
A method of driving a liquid crystal display panel having a plurality of scanning electrodes (L i , i being a positive integer) arranged parallel to each other, signal electrodes (S j , j being a positive integer) arranged parallel to each other intersecting the plurality of scanning electrodes, a plurality of pixels, one formed at each scanning and signal electrode intersection, and a ferroelectric liquid crystal sealed between the plurality of scanning electrodes and the plurality of signal electrodes, comprising the steps of: applying a compensation voltage G, comprising a voltage which becomes positive for a predetermined time period, followed by a succeeding erasing voltage H, comprising a voltage which becomes negative for said predetermined time period, and thereafter applying a selection voltage A, comprising, in a first half of said predetermined time period, a negative voltage approximately equal to the succeeding erasing voltage H, and comprising in the second half of said predetermined time period, a positive voltage approximately equal to said compensation voltage G, to the scanning electrode L i corresponding to a pixel to be displayed out of said plurality of pixels; and applying a bright voltage D, comprising in said first half of said predetermined time period, a positive voltage approximately equal to said selection voltage A in the second half of the predetermined time period, and comprising in the second half of the predetermined time period, a negative voltage approximately equal to said selection voltage A in the first half of the predetermined time period, to the signal electrode corresponding to said pixel to be displayed, to thereby turn ON the corresponding pixel.
Claim 2
Independent Claim
269 words
A method of driving a liquid crystal display panel having a plurality of scanning electrodes (L i , i being a positive integer) arranged parallel to each other, signal electrodes (S j , j being a positive integer) arranged parallel to each other intersecting the plurality of scanning electrodes, a plurality of pixels, one formed at each scanning and signal electrode intersection, and a ferroelectric liquid crystal sealed between the plurality of scanning electrodes and the plurality of signal electrodes, comprising the steps of: applying a compensation voltage G, comprising a voltage which becomes positive for a predetermined time period, followed by a succeeding erasing voltage H, comprising a voltage which becomes negative for said predetermined time period, and thereafter applying a selection voltage A, comprising, in a first half of said predetermined time period, a negative voltage approximately equal to the succeeding erasing voltage H, and comprising in the second half of said predetermined time period, a positive voltage approximately equal to said compensation voltage G, to the scanning electrode L i corresponding to a pixel to be displayed out of said plurality of pixels; and applying a bright voltage D, comprising in said first half of said predetermined time period, a positive voltage approximately equal to said selection voltage A in the second half of the predetermined time period, and comprising in the second half of the predetermined time period, a negative voltage approximately equal to said selection voltage A in the first half of the predetermined time period, to the signal electrode corresponding to said pixel to be displayed, to thereby turn ON the corresponding pixel.
Claim 3
Dependent Claim
102 words
The method of driving a ferroelectric liquid crystal display panel of claim 1, further comprising the steps of: applying a dark voltage E, comprising in the first half of the predetermined time period, a positive voltage lower in value than the bright voltage D in the first half of the predetermined time period, and comprising in the second half of the predetermined time period, a negative voltage greater in value than said bright voltage D in the second half of the predetermined time period, to the signal electrode corresponding to said pixel to be displayed, to thereby turn OFF the corresponding pixel.
Claim 4
Dependent Claim
151 words
The method of driving a ferroelectric liquid crystal display panel of claim 2, further comprising the step of: applying a non-selection voltage B, comprising, in the first half of the predetermined time period, a positive voltage lower in value than said selection voltage A in the second half of the predetermined time period and higher in value than said dark voltage E in the first half of the predetermined time period, and comprising in the second half of the predetermined time period, a negative voltage higher in value than said selection voltage A in the first half of the predetermined time period and lower in value than the dark voltage E in the second half of the predetermined time period, to the scanning electrodes corresponding to the pixels other than said pixel to be displayed, whereby the pixels other than said pixel to be displayed are set to a non-selected state.
References Cited (Backward Citations)
US4904064A
Cited
JPS62141520A
Cited
US4808991A
Cited
US4903875A
Cited
JPS6311912A
Cited
JPS6346078A
Cited
US4938574A
Cited
US4878741A
Cited
US4925277A
Cited
JPS6486774A
Cited
US4922240A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1994-09-16 | 1995-03-18 | 1995-09-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-09-16 | 1999-03-18 | 1999-09-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-09-16 | 2003-03-18 | 2003-09-17 | $7700.00 | Window Closed / Lapsed |