US4601544A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Nematic liquid crystal storage display device
Assignee: Nokia Bell Labs
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Filing: 1985-10-17
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Granted: 1986-07-22
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Expires: 2005-10-17
Abstract
Abstract A bistable nematic liquid crystal display cell is electrically switched between topologically equivalent, asymmetric horizontal states. The cell includes upper and lower parallel substrates, upper and lower topographically textured tilt alignment surfaces on the corresponding substrates, and nematic liquid crystal material between the substrates. In an active region of the cell, the tilt alignment surfaces form an unequal reverse tilt boundary condition. In an isolation region surrounding the active region of the cell, the tilt alignment surfaces are formed to avoid the reverse tilt boundary condition.
Inventors
- 👤 Julian Cheng
- 👤 Robert N. Thurston
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 06:29
CPC Classifications
G; G02; G02F; G02F1/00; G02F1/01; G02F1/13; G02F1/137; G02F1/139; G02F1/1391
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
114 words
A liquid crystal display cell capable of being switched to a first state under the influence of a first electric potential and to a second state under the influence of a second electric potential, switching between said first state and said second state being in the absence of movement of a disclination in said display cell, the cell comprising first and second substrates, and a nematic liquid crystal material having orientational directors disposed between both substrates, the cell comprising means integrally connected to each substrate for preferentially attracting an inversion layer of orientational directors to be substantially adjacent and parallel to the first substrate so that the directors are aligned in the first state.
Claim 2
Dependent Claim
114 words
A liquid crystal display cell capable of being switched to a first state under the influence of a first electric potential and to a second state under the influence of a second electric potential, switching between said first state and said second state being in the absence of movement of a disclination in said display cell, the cell comprising first and second substrates, and a nematic liquid crystal material having orientational directors disposed between both substrates, the cell comprising means integrally connected to each substrate for preferentially attracting an inversion layer of orientational directors to be substantially adjacent and parallel to the first substrate so that the directors are aligned in the first state.
Claim 3
Dependent Claim
89 words
The display cell as defined in claim 1 wherein the attracting means includes, on at least a portion of an interior surface of each substrate, a topographically textured surface uniformly tilted with respect to the adjacent substrate normal by an acute surface tilt angle, the tilt angle for the topographically textured surface on the first substrate being greater than and of opposite polarity to the tilt angle for the topographically textured surface on the second substrate so that both topographically textured surfaces form an unequal reverse tilt boundary condition.
Claim 4
Dependent Claim
24 words
The display cell as defined in claim 2 wherein each topographically textured surface has an azimuthal bias with respect to a predetermined reference line.
Claim 5
Dependent Claim
52 words
The display cell as defined in claim 3 wherein the topographically textured surface on the first substrate has an azimuthal bias angle which is in the range from -90 degrees to +90 degrees, exclusively, and wherein the topographically textured surface on the second substrate has an azimuthal bias angle of 0 degrees.
Claim 6
Dependent Claim
152 words
A liquid crystal display cell capable of being switched to a first state under the influence of a first electric potential and to a second state under the influence of a second electric potential, switching between said first state and said second state being in the absence of movement of a disclination in said display cell, the cell comprising first and second substrates, and a nematic liquid crystal material having orientational directors disposed between both substrates, the cell comprising first means integrally connected to each substrate for preferentially attracting an inversion layer of orientational directors to be substantially adjacent and parallel to the first substrate so that the directors are aligned in the first state, and the cell comprising second means integrally connected to each substrate for preferentially attracting the inversion layer to be substantially adjacent and parallel to the second substrate so that the directors are aligned in the second state.
Claim 7
Dependent Claim
152 words
A liquid crystal display cell capable of being switched to a first state under the influence of a first electric potential and to a second state under the influence of a second electric potential, switching between said first state and said second state being in the absence of movement of a disclination in said display cell, the cell comprising first and second substrates, and a nematic liquid crystal material having orientational directors disposed between both substrates, the cell comprising first means integrally connected to each substrate for preferentially attracting an inversion layer of orientational directors to be substantially adjacent and parallel to the first substrate so that the directors are aligned in the first state, and the cell comprising second means integrally connected to each substrate for preferentially attracting the inversion layer to be substantially adjacent and parallel to the second substrate so that the directors are aligned in the second state.
Claim 8
Dependent Claim
87 words
The display cell as defined in claim 5 wherein the first attracting means includes, on a first portion of an interior surface of each substrate, a topographically textured surface uniformly tilted with respect to the adjacent substrate normal by an acute surface tilt angle, the angle for the topographically textured surface on the first substrate being greater than and of opposite polarity to the angle for the topographically textured surface on the second substrate so that both topographically textured surfaces form an unequal reverse tilt boundary condition.
Claim 9
Dependent Claim
24 words
The display cell as defined in claim 6 wherein each topographically textured surface has an azimuthal bias with respect to a predetermined reference line.
Claim 10
Dependent Claim
49 words
The display cell as defined in claim 7 wherein the topographically textured surface on the first substrate has an azimuthal bias angle in the range from -90 degrees to +90 degrees, exclusively, and the topographically textured surface on the second substrate has an azimuthal bias angle of 0 degrees.
Claim 11
Dependent Claim
81 words
The display cell as defined in claim 8 wherein the second attracting means includes, on a second portion of the interior surface of the second substrate surrounding the first portion, a topographically textured surface uniformly tilted with respect to the adjacent substrate normal by an acute surface tilt angle, the angle on the second portion of the surface being of opposite polarity to the angle on the first portion of the same surface so that an orientational discontinuity is formed thereon.
Claim 12
Dependent Claim
69 words
The display cell as defined in claim 8 wherein the second attracting means includes, on a second portion of the interior surface of each substrate surrounding each first portion, a topographically textured surface both uniformly tilted with respect to the adjacent substrate normal by an acute surface tilt angle and having an azimuthal bias with respect to the topographically textured surface on the first portion of the same substrate.
Claim 13
Dependent Claim
42 words
The display cell as defined in claim 10 wherein the azimuthal bias for the second portion of the interior surface of the first substrate is greater than the azimuthal bias for the second portion of the interior surface of the second substrate.
References Cited (Backward Citations)
US4333708A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-07-21 | 1990-01-20 | 1990-07-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-07-21 | 1994-01-20 | 1994-07-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-07-21 | 1998-01-20 | 1998-07-22 | $7700.00 | Window Closed / Lapsed |