US5233459A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electric display device
Assignee: Massachusetts Institute of Technology
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Filing: 1991-03-06
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Granted: 1993-08-03
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Expires: 2011-03-06
Abstract
Abstract A bistable electrostatic light valve display in which a movable electrode is disposed opposite a fixed electrode and is biased to move in a preferred direction upon application of an electric field across the electrodes to produce a light valve or light shutter. In one embodiment, the movable electrode is restrained at one end and coils about the fixed end in a preferential roll direction. The bias is achieved by inducing anisotropic stress or anisotropic stiffness. In another embodiment, the moveable electrode is restrained at both ends and is biased upwardly by anisotropic stress or stiffening.
Inventors
- 👤 Carl O. Bozler
- 👤 Steven Rabe
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 03:59
CPC Classifications
G; G02; G02B; G02B26/00; G02B26/02; G02B26/08; G02B26/0816; G02B26/0833; G02B26/0841; G09; G09F; G09F9/00; G09F9/30; G09F9/37; G09F9/372; G01; G01J; G01J3/00; G01J3/02; G01J3/0205; G01J3/0232; H; H01; H01H; H01H1/00; H01H1/0036; H01H2001/0042; H01H59/00; H01H59/0009; H01H2059/0018; H01H2059/0081
Claims Analysis
Total Claims: 25
Claim 1
Independent Claim
113 words
An electrostatic light valve comprising: a) a fixed electrode formed on a substrate; b) a first high resistance layer on said fixed electrode; c) a movable electrode formed with an anisotropic stress in a predetermined direction and disposed adjacent said fixed electrode with a second high resistive layer formed between the movable electrode and the first high resistance layer; and d) wherein the fixed electrode, high resistance layers and movable electrode are portions of a monolithic thin film structure and the movable electrode is formed of two layers of metal, one of which is nearer the substrate and is formed with compressive stress and the other of which is formed with tensile stress.
Claim 2
Dependent Claim
113 words
An electrostatic light valve comprising: a) a fixed electrode formed on a substrate; b) a first high resistance layer on said fixed electrode; c) a movable electrode formed with an anisotropic stress in a predetermined direction and disposed adjacent said fixed electrode with a second high resistive layer formed between the movable electrode and the first high resistance layer; and d) wherein the fixed electrode, high resistance layers and movable electrode are portions of a monolithic thin film structure and the movable electrode is formed of two layers of metal, one of which is nearer the substrate and is formed with compressive stress and the other of which is formed with tensile stress.
Claim 3
Dependent Claim
27 words
The valve of claim 1 wherein the resistive layers have a thickness and the resistance of regions of the resistive layers perpendicular to the thickness is equal.
Claim 4
Dependent Claim
14 words
The valve of claim 2 wherein the thickness of the resistive layers is equal.
Claim 5
Dependent Claim
11 words
The valve of claim 1 wherein the movable electrode is corrugated.
Claim 6
Dependent Claim
25 words
The valve of claim 1 wherein the movable electrode is coiled in a roll after formation and is anisotropically stressed in the direction of roll.
Claim 7
Dependent Claim
15 words
The valve of claim 5 further including spacer rails between the fixed and movable electrode.
Claim 8
Dependent Claim
13 words
The valve of claim 6 wherein the rails extend along the roll direction.
Claim 9
Dependent Claim
13 words
The valve of claim 6 wherein the rails extend transverse the roll direction.
Claim 10
Dependent Claim
34 words
The valve of claim 1 wherein the movable electrode is formed of a film having compressive stress on a side facing the fixed electrode and tensile stress on an opposite side of the film.
Claim 11
Dependent Claim
37 words
The valve of claim 1 wherein the movable electrode is coiled in a roll and unrolls in a first direction when a voltage is applied across the electrodes and has anisotropic stress in the direction of roll.
Claim 12
Dependent Claim
24 words
The valve of claim 1 wherein the movable electrode is formed of a conductive film having a thickness of less than about 3000 Angstroms.
Claim 13
Dependent Claim
28 words
The valve of claim 1 wherein the fixed electrode is comprised of a thin layer of material from the group comprising indium, tin, gold, silver, platinum or tungsten.
Claim 14
Dependent Claim
24 words
The valve of claim 1 wherein the first high resistance layer is formed of material from the group comprising silicon dioxide or silicon nitride.
Claim 15
Dependent Claim
29 words
The valve of claim 1 wherein the net stress of the two layers of the movable electrode is low compared with the stress of each of said two layers.
Claim 16
Dependent Claim
26 words
The valve of claim 1 wherein the movable electrode is formed into a roll and an electric potential applied across the electrodes unrolls the movable electrode.
Claim 17
Dependent Claim
23 words
The valve of claim 1 wherein the two layers are formed of material from the group comprising tungsten, chromium, titanium, magnesium or aluminum.
Claim 18
Dependent Claim
30 words
The valve of claim 1 wherein the light valve is a monolithic structure formed of thin films and wherein the movable electrode is formed on the second high resistive layer.
Claim 19
Dependent Claim
118 words
An electrostatic light valve comprising: a) a fixed electrode formed on a substrate; b) a first high resistance layer on said fixed electrode; c) a movable electrode formed adjacent said fixed electrode and coiled in a roll after formation and anisotropically stressed in the direction of roll with a second high resistive layer formed between the movable electrode and the first high resistance layer: and d) wherein the fixed electrode, high resistance layers and movable electrode are portions of a monolithic thin film structure and the movable electrode is formed of two layers of metal, one of which is nearer the substrate and is formed with compressive stress and the other of which is formed with tensile stress.
Claim 20
Dependent Claim
118 words
An electrostatic light valve comprising: a) a fixed electrode formed on a substrate; b) a first high resistance layer on said fixed electrode; c) a movable electrode formed adjacent said fixed electrode and coiled in a roll after formation and anisotropically stressed in the direction of roll with a second high resistive layer formed between the movable electrode and the first high resistance layer: and d) wherein the fixed electrode, high resistance layers and movable electrode are portions of a monolithic thin film structure and the movable electrode is formed of two layers of metal, one of which is nearer the substrate and is formed with compressive stress and the other of which is formed with tensile stress.
Claim 21
Dependent Claim
27 words
The valve of claim 18 wherein the net stress of the two layers of metal is low compared with the stress of each of said two layers.
Claim 22
Dependent Claim
23 words
The valve of claim 18 wherein the two layers are formed of material from the group comprising tungsten, chromium, titanium, magnesium or aluminum.
Claim 23
Dependent Claim
15 words
The valve of claim 18 further including spacer rails between the fixed and movable electrode.
Claim 24
Dependent Claim
13 words
The valve of claim 21 wherein the rails extend along the roll direction.
Claim 25
Dependent Claim
13 words
The valve of claim 21 wherein the rails extend transverse the roll direction.
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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) | 1996-08-02 | 1997-02-01 | 1997-08-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-08-02 | 2001-02-01 | 2001-08-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-08-02 | 2005-02-01 | 2005-08-03 | $7700.00 | Window Closed / Lapsed |