US3723749A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Driving circuit for liquid crystal displays
Assignee: Timex Group USA Inc
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Filing: 1972-04-14
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Granted: 1973-03-27
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Expires: 1992-04-14
Abstract
Abstract A driving circuit for liquid crystal displays is disclosed. The circuit comprises a single field effect transistor which operates in two different modes to drive the display. The field effect transistor (FET) is connected between a high voltage inverter and the display while a second high voltage inverter is also connected to the display. When input signals are fed to the FET, it acts as an inverter in one direction and as a source follower in the other direction driving the liquid crystal display with AC voltage.
Inventors
- 👤 R Shapiro
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 18:24
CPC Classifications
G; G09; G09G; G09G3/00; G09G3/04; G09G3/16; G09G3/18
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
79 words
A driving circuit for a liquid crystal display having a first and second terminal for receiving or transmitting signals which comprises: a first high voltage inverter connected to the first terminal of the display, a field effect transistor connected to the second terminal of the display, and a second high voltage inverter connected to the field effect transistor, said transistor controlling the operation of the display when the signal level of a control signal to the transistor is varied.
Claim 2
Dependent Claim
79 words
A driving circuit for a liquid crystal display having a first and second terminal for receiving or transmitting signals which comprises: a first high voltage inverter connected to the first terminal of the display, a field effect transistor connected to the second terminal of the display, and a second high voltage inverter connected to the field effect transistor, said transistor controlling the operation of the display when the signal level of a control signal to the transistor is varied.
Claim 3
Dependent Claim
34 words
A driving circuit in accordance with claim 1 wherein: the first high voltage rectifier and the second high voltage rectifier have unsymmetrical duty cycles to eliminate any DC bias across the liquid crystal display.
Claim 4
Dependent Claim
26 words
A driving circuit in accordance with claim 2 wherein: the field effect transistor has an off impedance substantially higher than that of the liquid crystal display.
Claim 5
Dependent Claim
58 words
A driving circuit for a liquid crystal numeric display comprising a plurality of segments which includes: a first and a second high voltage inverter having the segments connected in parallel therebetween, and a control element connected between each display and the second high voltage inverter and having an input to receive control signals to operate the corresponding segment.
Claim 6
Dependent Claim
58 words
A driving circuit for a liquid crystal numeric display comprising a plurality of segments which includes: a first and a second high voltage inverter having the segments connected in parallel therebetween, and a control element connected between each display and the second high voltage inverter and having an input to receive control signals to operate the corresponding segment.
Claim 7
Dependent Claim
16 words
A driving circuit in accordance with claim 4 wherein: the control elements are field effect transistors.
Claim 8
Dependent Claim
19 words
A driving circuit in accordance with claim 4 wherein: the control elements are n-channel or p-channel enhancement type MOSFETs.
Claim 9
Dependent Claim
65 words
A driving circuit for a liquid crystal display comprising: a first and a second high voltage inverter connected to the liquid crystal display, and a field effect transistor connected between one of the inverters and the display, said transistor acting as an inverter in one direction when input signals are fed thereto and as a source follower in the other direction thereby driving the display.
Claim 10
Dependent Claim
65 words
A driving circuit for a liquid crystal display comprising: a first and a second high voltage inverter connected to the liquid crystal display, and a field effect transistor connected between one of the inverters and the display, said transistor acting as an inverter in one direction when input signals are fed thereto and as a source follower in the other direction thereby driving the display.
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) | 1976-03-26 | 1976-09-25 | 1977-03-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-03-26 | 1980-09-25 | 1981-03-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-03-26 | 1984-09-25 | 1985-03-27 | $7700.00 | Window Closed / Lapsed |