Patent US4198630A successfully refreshed from Google Patents.
US4198630A
Expired / Lapsed
US
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Displays using thick film switches to control individual display elements
Assignee: Nortel Networks Ltd
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Filing: 1978-08-09
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Granted: 1980-04-15
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Expires: 1998-08-09
Abstract
Abstract Each element of a display operated in a scan mode is series connected to a thick film switch which sets a voltage threshold to isolate the element from periodic scan pulses unless coincident with an element selecting data pulse in which case the thick film switches and the element, for example, a nematic liquid crystal cell, operates.
Inventors
- 👤 Nur M. Serinken
- 👤 David R. Baraff
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 10:23
CPC Classifications
G; G02; G02F; G02F1/00; G02F1/01; G02F1/13; G02F1/132; G02F1/0147; G09; G09G; G09G3/00; G09G3/20; G09G3/34; G09G3/36; G09G3/3611; G09G3/367
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
96 words
A display cell comprising a plurality of display elements, each display element defined by a pair of spaced electrodes flanking a material whose optical transmissivity is dependent on potential difference applied thereacross, means for applying a potential difference between the electrodes of each element, a plurality of switch elements series-connected to respective display elements, each switch element comprising a thick film material having a large negative temperature coefficient of resistance in a predetermined switching temperature zone, wherein, in use, switch elements subjected to the predetermined threshold potential difference experience joule heating to said switching temperature zone.
Claim 2
Dependent Claim
96 words
A display cell comprising a plurality of display elements, each display element defined by a pair of spaced electrodes flanking a material whose optical transmissivity is dependent on potential difference applied thereacross, means for applying a potential difference between the electrodes of each element, a plurality of switch elements series-connected to respective display elements, each switch element comprising a thick film material having a large negative temperature coefficient of resistance in a predetermined switching temperature zone, wherein, in use, switch elements subjected to the predetermined threshold potential difference experience joule heating to said switching temperature zone.
Claim 3
Dependent Claim
16 words
A display cell as claimed in claim 1 in which said material is a liquid crystal.
Claim 4
Dependent Claim
29 words
A display cell as claimed in claim 2 in which the spaced electrodes and said thick film switches are formed on spaced transparent plates flanking a nematic liquid crystal.
Claim 5
Dependent Claim
53 words
A display cell as claimed in claim 2 in which said material is a cholesteric liquid crystal overlying a resistive material on a reflective substrate, the resistive material being adapted to undergo joule heating when said thick film switch switches whereby to heat the liquid crystal and so induce a transmissivity change therein.
Claim 6
Dependent Claim
18 words
A display cell as claimed in claim 1, in which said material comprises vanadium oxide (VO 2 ).
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) | 1983-04-15 | 1983-10-15 | 1984-04-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-04-15 | 1987-10-15 | 1988-04-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-04-15 | 1991-10-15 | 1992-04-15 | $7700.00 | Window Closed / Lapsed |