US5136404A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Liquid crystal writing slate with improved light-transmission retention
Assignee: GOLDEN BOOKS PUBLISHING COMPANY Inc
•
Filing: 1990-08-09
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Granted: 1992-08-04
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Expires: 2010-08-09
Abstract
Abstract A liquid crystal display device includes a base supporting a laminate which has an LC-layer (liquid crystal layer) formed of polymeric material holding micro-volumes of liquid crystal material, and a conductive layer on one surface of the LC-layer, the other surface of the LC-layer being substantially conductor-free, and apparatus for transitory application of potential through the LC-layer to the conductive layer to produce an image. The LC-layer has at least about 50% by weight of the polymeric material and less than 50% of the liquid crystal material by weight of the LC-layer, and the duration of image retention after transitory application of potential ceases is significantly extended.
Inventors
- 👤 Frederick E. Nobile
- 👤 John F. Harris, III
- 👤 Gary S. Silverman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 02:08
CPC Classifications
G; G02; G02F; G02F1/00; G02F1/01; G02F1/13; G02F1/133; G02F1/13306; G02F1/1333; G02F1/1334
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
145 words
In a device of the type having a liquid crystal layer providing two light-modulating characteristics, the improvement comprising: a laminate having an LC-layer with first and second surfaces and formed of polymeric material holding micro-volumes of liquid crystal material, and a conductive layer along the first surface, the second surface conductor-free on or along an image-accepting region of the laminate; movable means for selective transitory application of electrical potential through the LClayer to the conductive layer; and the LC-layer comprising at least 50% of the polymeric material and less than 50% of the liquid crystal material by weight of the LC-layer, the polymeric material having a volume resistivity of at least about 10 15 ohm-centimeters, whereby the laminate has charge-retaining capabilities such that a light-modulating characteristic formed on the image-accepting region by transitory application of potential thereto persists for an extended duration following such application.
Claim 2
Dependent Claim
145 words
In a device of the type having a liquid crystal layer providing two light-modulating characteristics, the improvement comprising: a laminate having an LC-layer with first and second surfaces and formed of polymeric material holding micro-volumes of liquid crystal material, and a conductive layer along the first surface, the second surface conductor-free on or along an image-accepting region of the laminate; movable means for selective transitory application of electrical potential through the LClayer to the conductive layer; and the LC-layer comprising at least 50% of the polymeric material and less than 50% of the liquid crystal material by weight of the LC-layer, the polymeric material having a volume resistivity of at least about 10 15 ohm-centimeters, whereby the laminate has charge-retaining capabilities such that a light-modulating characteristic formed on the image-accepting region by transitory application of potential thereto persists for an extended duration following such application.
Claim 3
Dependent Claim
13 words
The device of claim 1 wherein the LC-layer is a polymer-dispersed liquid crystal.
Claim 4
Dependent Claim
10 words
The device of claim 2 wherein the laminate is flexible.
Claim 5
Dependent Claim
32 words
The device of claim 1 wherein the LC-layer comprises at least about 60% of the polymeric material and less than about 40% of the liquid crystal material by weight of the LC-layer.
Claim 6
Dependent Claim
22 words
The device of claim 1 wherein the laminate further includes a non-conductive overlayer on the second surface, whereby the LC-layer is protected.
Claim 7
Dependent Claim
11 words
The device of claim 5 wherein the non-conductive overlayer is polyester.
Claim 8
Dependent Claim
20 words
The device of claim 1 wherein the polymer is selected from the group consisting of polyvinyl acetates, acrylics and urethanes.
Claim 9
Dependent Claim
12 words
The device of claim 7 wherein the polymer is an acrylic resin.
Claim 10
Dependent Claim
22 words
The device of claim 8 wherein the laminate further includes a non-conductive overlayer on the second surface, whereby the LC-layer is protected.
Claim 11
Dependent Claim
11 words
The device of claim 9 wherein the non-conductive overlayer is polyester.
Claim 12
Dependent Claim
24 words
The device of claim 1 wherein the conductive layer is transparent, whereby the laminate transmits light therethrough in one of said two visual characteristics.
Claim 13
Dependent Claim
44 words
The device of claim 1 wherein the means for application of potential comprises: a voltage source; power supply means electrically attached to the voltage source for providing said electrical potential; and means for extending the potential from the power supply to the second surface.
Claim 14
Dependent Claim
33 words
The device of claim 12 wherein the extending means comprises: an applicator having a conductive region for contact with the laminate; and a flexible electrical cord connecting the applicator to the power supply.
Claim 15
Dependent Claim
39 words
The device of claim 12 wherein the extending means comprises an exposed surface electrically connected to the power supply, whereby a person's body contacting the exposed surface can extend the potential from the power supply to the second surface.
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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) | 1995-08-04 | 1996-02-03 | 1996-08-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-08-04 | 2000-02-03 | 2000-08-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-08-04 | 2004-02-03 | 2004-08-04 | $7700.00 | Window Closed / Lapsed |