US4738515A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Driving method for liquid crystal device
Assignee: Canon Inc
•
Filing: 1986-08-01
•
Granted: 1988-04-19
•
Expires: 2006-08-01
Abstract
Abstract A driving method for a liquid crystal device of the type comprising arranged picture elements each comprising oppositely spaced electrodes, and a ferroelectric liquid crystal layer and a dielectric layer disposed between the electrodes, the ferroelectric liquid crystal layer having a resistance R(Ω) and a capacitance C 1 (F), the dielectric layer having a capacitance C 2 (F); wherein a driving voltage having a pulse duration ΔT(sec) set to satisfy the following formula (1) is applied to the picture elements: ##EQU1## wherein a is a coefficient satisfying the relationship of a<|-Va|/|V ON |, V ON is a value of voltage (volt) applied to a picture element at the time of writing, -Va is a value of voltage (volt) of a reverse polarity applied to the picture element after the application of the writing voltage V ON , b is a coefficient defined by the equation of b=|V 1 |/|V ON |, and V 1 is the inversion initiation voltage (volts) of the liquid crystal layer.
Inventors
- 👤 Shinjiro Okada
- 👤 Osamu Taniguchi
- 👤 Yutaka Inaba
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 13:43
CPC Classifications
G; G09; G09G; G09G3/00; G09G3/20; G09G3/34; G09G3/36; G09G3/3611; G09G3/3622; G09G3/3629; G09G2310/00; G09G2310/06; G09G2310/061
Claims Analysis
Total Claims: 25
Claim 1
Independent Claim
165 words
A driving method for a liquid crystal device of the type comprising arranged picture elements each comprising oppositely spaced electrodes, and a ferroelectric liquid crystal layer and a dielectric layer disposed between the electrodes, said ferroelectric liquid crystal layer having a resistance R(Ω) and a capacitance C 1 (F), said dielectric layer having a capacitance C 2 (F); wherein a driving voltage having a pulse duration ΔT(sec) set to satisfy the following formula (1) is applied to the picture elements: ##EQU7## wherein a is a coefficient satisfying the relationship of a<|-Va|/|V ON |, V ON is a value of voltage (volt) applied to a picture element at the time of writing, -Va is a value of voltage (volt) of a reverse polarity applied to the picture element after the application of the writing voltage V ON , b is a coefficient defined by the equation of b=|V 1 |/|V ON |, and V 1 is the inversion initiation voltage (volts) of the liquid crystal layer.
Claim 2
Dependent Claim
165 words
A driving method for a liquid crystal device of the type comprising arranged picture elements each comprising oppositely spaced electrodes, and a ferroelectric liquid crystal layer and a dielectric layer disposed between the electrodes, said ferroelectric liquid crystal layer having a resistance R(Ω) and a capacitance C 1 (F), said dielectric layer having a capacitance C 2 (F); wherein a driving voltage having a pulse duration ΔT(sec) set to satisfy the following formula (1) is applied to the picture elements: ##EQU7## wherein a is a coefficient satisfying the relationship of a<|-Va|/|V ON |, V ON is a value of voltage (volt) applied to a picture element at the time of writing, -Va is a value of voltage (volt) of a reverse polarity applied to the picture element after the application of the writing voltage V ON , b is a coefficient defined by the equation of b=|V 1 |/|V ON |, and V 1 is the inversion initiation voltage (volts) of the liquid crystal layer.
Claim 3
Dependent Claim
18 words
A driving method according to claim 1, wherein said ferroelectric liquid crystal is formed in a bistability condition.
Claim 4
Dependent Claim
25 words
A driving method according to claim 1, wherein said ferroelectric liquid crystal has a resistance in the range of 10 8 to 10 14 Ω.
Claim 5
Dependent Claim
21 words
A driving method according to claim 1, wherein said dielectric layer has a capacitance of 5.5×10 3 pF/cm 2 or above.
Claim 6
Dependent Claim
28 words
A driving method according to claim 1, wherein said dielectric layer has a capacitance in the range of 5.5×10 3 pF/cm 2 to 3.0×10 5 pF/cm 2 .
Claim 7
Dependent Claim
25 words
A driving method according to claim 1, wherein said dielectric layer has a capacitance of 9×10 3 pb/cm 2 to 5.5×10 4 pF/cm 2 .
Claim 8
Dependent Claim
97 words
A driving method according to claim 1, wherein said picture elements are arranged in a plurality of rows and columns, a driving voltage for providing a first display state based on a first orientation state of the ferroelectric liquid crystal is applied row by row and sequentially to all or a part of the picture elements on a row in a first phase, and a driving voltage for providing a second display state based on a second orientation state of the ferroelectric liquid crystal is applied to selected picture elements on the row in a second phase.
Claim 9
Dependent Claim
17 words
A driving method according to claim 7, which includes a third phase for applying an auxiliary signal.
Claim 10
Dependent Claim
93 words
A driving method according to claim 1, wherein said picture elements are arranged in a plurality of rows and columns, a driving voltage for providing a first display state based on a first orientation state of the ferroelectric liquid crystal is applied row by row and sequentially to selected picture elements on a row in a first phase, and a driving voltage for providing a second display state based on a second orientation state of the ferroelectric liquid crystal is applied to other selected picture elements on the row in a second phase.
Claim 11
Dependent Claim
17 words
A driving method according to claim 9, which includes a third phase for applying an auxiliary signal.
Claim 12
Dependent Claim
18 words
A driving method according to claim 1, wherein said ferroelectric liquid crystal is placed under a bistability condition.
Claim 13
Dependent Claim
18 words
A driving method according to claim 1, wherein said ferroelectric liquid crystal is a chiral smectic liquid crystal.
Claim 14
Dependent Claim
32 words
A driving method according to claim 12, wherein said chiral smectic liquid crystal is in chiral smectic C phase, H phase, I phase, J phase, K phase, G phase or F phase.
Claim 15
Dependent Claim
15 words
A driving method according to claim 1, wherein said coefficient a is 1/2 or less.
Claim 16
Dependent Claim
15 words
A driving method according to claim 1, wherein said coefficient a is 1/3 or less.
Claim 17
Dependent Claim
19 words
A driving method according to claim 1, wherein said coefficient b is in the range of 5/6 to 1.
Claim 18
Dependent Claim
19 words
A driving method according to claim 1, wherein said dielectric layer has been subjected to a uniaxial orientation treatment.
Claim 19
Dependent Claim
14 words
A driving method according to claim 17, wherein said uniaxial orientation treatment is rubbing.
Claim 20
Dependent Claim
33 words
A driving method according to claim 1, wherein said dielectric layer is a laminate of at least two dielectric layers, the upper one of which has been subjected to a uniaxial orientation treatment.
Claim 21
Dependent Claim
14 words
A driving method according to claim 19, wherein said uniaxial orientation treatment is rubbing.
Claim 22
Dependent Claim
16 words
A driving method according to claim 1, wherein said dielectric layer is a color filter layer.
Claim 23
Dependent Claim
43 words
A driving method according to claim 1, wherein said dielectric layer is a laminate of at least two dielectric layers, of which a lower dielectric layer is a color filter layer and the upper layer has been subjected to a uniaxial orientation treatment.
Claim 24
Dependent Claim
14 words
A driving method according to claim 22, wherein said uniaxial orientation treatment is rubbing.
Claim 25
Dependent Claim
24 words
A driving method according to claim 1, wherein said dielectric layer is a film of an inorganic insulating material or an organic insulating material.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-04-19 | 1991-10-19 | 1992-04-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-04-19 | 1995-10-19 | 1996-04-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-04-19 | 1999-10-19 | 2000-04-19 | $7700.00 | Window Closed / Lapsed |