US4488818A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Watch with an analog display device the dial of which is formed by a liquid crystal display cell
Assignee: Asulab AG
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Filing: 1982-09-29
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Granted: 1984-12-18
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Expires: 2002-09-29
Abstract
Abstract A watch display comprises time display hands (3, 4) and a reflecting digital display (5) which acts as dial for the hands, the display being transparent under the effect of an electric field and opaque in the absence of the field.
Inventors
- 👤 Eric Saurer
- 👤 Fereydoun Gharadjedaghi
- 👤 Yves Ruedin
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 23:41
CPC Classifications
G; G04; G04G; G04G9/00; G04G9/0082; G04G9/0094
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
159 words
In a watch comprising time display hands adapted to be mechanically driven; and a digital display cell positioned behind said hands to form a dial for said hands, said digital display cell including a composite layer comprising at least one layer of liquid crystal and having display zones which respond to an electrical field provided in response to an external action by a modification of their opacity; a fluid-tight enclosure comprising a front plate, a rear plate and spacing and closing means which define a closed space containing the layer of liquid crystal; and light-reflecting and diffusing means disposed behind said composite layer; the improvement wherein said cell is of the type in which said composite layer is transparent under the effect of said field and opaque in the absence of the field, with the result that said layer has a uniformly opaque appearance in the absence of said field and thus forms itself the dial for said hands.
Claim 2
Dependent Claim
159 words
In a watch comprising time display hands adapted to be mechanically driven; and a digital display cell positioned behind said hands to form a dial for said hands, said digital display cell including a composite layer comprising at least one layer of liquid crystal and having display zones which respond to an electrical field provided in response to an external action by a modification of their opacity; a fluid-tight enclosure comprising a front plate, a rear plate and spacing and closing means which define a closed space containing the layer of liquid crystal; and light-reflecting and diffusing means disposed behind said composite layer; the improvement wherein said cell is of the type in which said composite layer is transparent under the effect of said field and opaque in the absence of the field, with the result that said layer has a uniformly opaque appearance in the absence of said field and thus forms itself the dial for said hands.
Claim 3
Dependent Claim
84 words
The watch of claim 1, wherein the composite layer comprises a first polarizer located in front of the layer of liquid crystal and a second polarizer located between the layer of liquid crystal and said light-reflecting and -diffusing means; the layer of liquid crystal has a helical structure the axis of which is substantially at a right angle to the plane of said layer, the angle of twist of the helix being 90°; and the axes of said polarizer are parallel to each other.
Claim 4
Dependent Claim
27 words
The watch of claim 1, wherein the composite layer further comprises a polarizer and the layer of liquid crystal comprises a nematic compound and a pleochroic dye.
Claim 5
Dependent Claim
14 words
The watch of claim 3, wherein said polarizer is adjacent to the light-reflecting means.
Claim 6
Dependent Claim
30 words
The watch of claim 1, wherein the layer of liquid crystal comprises a nematic compound, a pleochroic dye and a chiralic compound which induces a helical structure in said layer.
Claim 7
Dependent Claim
28 words
The watch of claims 3, 4 or 5, wherein the pleochroic dye has a relatively high coefficient of absorption for substantially all of the wave-lengths of visible light.
Claim 8
Dependent Claim
31 words
The watch of claim 3, 4 or 5 wherein said spacing and closing means comprises a bonding material and a pigmentation agent having substantially the same colour as the pleochroic dye.
Claim 9
Dependent Claim
24 words
The Watch of claims 1, 2, 3, 4 or 5 wherein the front plate carries a partly reflective layer on one of its surfaces.
Claim 10
Dependent Claim
28 words
The watch of claim 6 wherein said spacing and closing means comprises a bonding material and a pigmentation agent having substantially the same colour as the pleochroic dye.
Claim 11
Dependent Claim
19 words
The watch of claim 6 wherein the front plate carries a partly reflective layer on one of its surfaces.
Claim 12
Dependent Claim
19 words
The watch of claim 7 wherein the front plate carries a partly reflective layer on one of its surfaces.
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) | 1987-12-18 | 1988-06-18 | 1988-12-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-12-18 | 1992-06-18 | 1992-12-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-12-18 | 1996-06-18 | 1996-12-18 | $7700.00 | Window Closed / Lapsed |