US3833833A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Drive circuitry for light emitting film displays
Assignee: Individual
•
Filing: 1973-08-20
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Granted: 1974-09-03
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Expires: 1993-08-20
Abstract
Abstract Driving circuitry for multiplexed light emitting film displays is shown wherein the unselected segment electrodes of a segment matrix and/or the unselected digit electrodes are connected together to prevent establishment of floating complex seriesparallel capacitance networks which could otherwise drive certain of the unselected electrodes to emit unwanted light. Also, the polarity of the voltage applied to inductors forming part of the electrode drive circuits is reversed during each segment drive cycle to eliminate decrease of light intensity of a respectively fired electrode due to energy losses incurred in the inductors and in the display.
Inventors
- 👤 A Nelson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 21:53
CPC Classifications
H; H05; H05B; H05B44/00
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
191 words
A drive circuit for a capacitive light emitting film display wherein a phosphor film is interposed between a series oF main electrodes on one side and a series of groups of secondary electrodes on the other side, each of said groups being associated with a respective one of said main electrodes, comprising inductors connected in circuit with respective ones of the electrodes of one of said series, power supply means for applying an electrical potential for different ones of said main electrodes, said power supply means including a group of main switching devices connected in circuit with respective ones of said main electrodes; power supply means for applying an electrical potential to said secondary electrodes, said last mentioned power supply means including a group of secondary switching devices connected in circuit with respective ones of said secondary electrodes whereby, when any of said main switching devices and any of said secondary switching devices associated with a last mentioned main switching device are simultaneously turned off, energy stored in respective ones of said electrodes to cause light emission; at least one of said groups of switching devices having a common electrical connection.
Claim 2
Dependent Claim
191 words
A drive circuit for a capacitive light emitting film display wherein a phosphor film is interposed between a series oF main electrodes on one side and a series of groups of secondary electrodes on the other side, each of said groups being associated with a respective one of said main electrodes, comprising inductors connected in circuit with respective ones of the electrodes of one of said series, power supply means for applying an electrical potential for different ones of said main electrodes, said power supply means including a group of main switching devices connected in circuit with respective ones of said main electrodes; power supply means for applying an electrical potential to said secondary electrodes, said last mentioned power supply means including a group of secondary switching devices connected in circuit with respective ones of said secondary electrodes whereby, when any of said main switching devices and any of said secondary switching devices associated with a last mentioned main switching device are simultaneously turned off, energy stored in respective ones of said electrodes to cause light emission; at least one of said groups of switching devices having a common electrical connection.
Claim 3
Dependent Claim
20 words
A drive circuit according to claim 1 wherein both of said groups of switching devices have respective common electrical connections.
Claim 4
Dependent Claim
20 words
A drive circuit according to claim 2 wherein both of said groups of switching devices have a common electrical connection.
Claim 5
Dependent Claim
150 words
A drive circuit for a capacitive light emitting film display wherein a phosphor film is interposed between a main electrode on one side and a plurality of secondary electrodes on the other side, comprising inductors connected in circuit with respective ones of said secondary electrodes, power supply means for applying an electrical potential to said secondary electrodes, said power supply means including a main switching device connected in circuit with said main electrode; power supply means for applying an electrical potential to said inductors, said last mentioned power supply means including secondary switching devices connected in circuit with respective ones of said inductors whereby, when said main switching device and any of said secondary switching devices are simultaneously turned off, energy stored in respective ones of said inductors will be transferred to respective ones of said secondary electrodes to cause light emission; said switching devices having a common electrical connection.
Claim 6
Dependent Claim
150 words
A drive circuit for a capacitive light emitting film display wherein a phosphor film is interposed between a main electrode on one side and a plurality of secondary electrodes on the other side, comprising inductors connected in circuit with respective ones of said secondary electrodes, power supply means for applying an electrical potential to said secondary electrodes, said power supply means including a main switching device connected in circuit with said main electrode; power supply means for applying an electrical potential to said inductors, said last mentioned power supply means including secondary switching devices connected in circuit with respective ones of said inductors whereby, when said main switching device and any of said secondary switching devices are simultaneously turned off, energy stored in respective ones of said inductors will be transferred to respective ones of said secondary electrodes to cause light emission; said switching devices having a common electrical connection.
Claim 7
Dependent Claim
20 words
A drive circuit according to claim 4 comprising means for alternately applying different voltage potentials to said common electrical connection.
Claim 8
Dependent Claim
22 words
A drive circuit according to claim 4 comprising means for alternately applying voltage potentials of different polarities to said common electrical connection.
Claim 9
Dependent Claim
23 words
A drive circuit according to claim 5 comprising means for concurrently operating said last mentioned means and for turning off said switching devices.
Claim 10
Dependent Claim
164 words
A drive circuit for a capacitive light emitting film display wherein a phosphor film is interposed between a main electrode on one side and a plurality of secondary electrodes on the other side, comprising a main inductor connected in circuit with said main electrode, secondary inductors connected in circuit with respective ones of said secondary electrodes, power supply means for applying an electrical potential to said main inductor, said power means including a main switching device connected in circuit with said main inductor, power supply means for applying an electrical potential to said secondary inductors, said last mentioned power supply means including secondary switching devices connected in circuit with respective ones of said secondary inductors whereby, when said main switching device and any of said secondary switching devices are simultaneously turned off, energy stored in respective ones of said inductors will be transferred to respective ones of said electrodes to cause light emission, said main and secondary switching means having a common electrical connection.
Claim 11
Dependent Claim
164 words
A drive circuit for a capacitive light emitting film display wherein a phosphor film is interposed between a main electrode on one side and a plurality of secondary electrodes on the other side, comprising a main inductor connected in circuit with said main electrode, secondary inductors connected in circuit with respective ones of said secondary electrodes, power supply means for applying an electrical potential to said main inductor, said power means including a main switching device connected in circuit with said main inductor, power supply means for applying an electrical potential to said secondary inductors, said last mentioned power supply means including secondary switching devices connected in circuit with respective ones of said secondary inductors whereby, when said main switching device and any of said secondary switching devices are simultaneously turned off, energy stored in respective ones of said inductors will be transferred to respective ones of said electrodes to cause light emission, said main and secondary switching means having a common electrical connection.
Claim 12
Dependent Claim
34 words
A drive circuit according to claim 7 wherein said main inductor is connected in series with said main electrode and said secondary inductors are connected in series with respective ones of said secondary electrodes.
Claim 13
Dependent Claim
50 words
A drive circuit according to claim 8 wherein said main switching device comprises a switching transistor connected to a point intermediate said main inductor and said main electrode, and said secondary switching device comprises switching transistors connected to points intermediate said secondary inductors and respective ones of said secondary electrodes.
Claim 14
Dependent Claim
13 words
A drive circuit according to claim 10 comprising means for back-biasing said transistors.
Claim 15
Dependent Claim
22 words
A drive circuit according to claim 8 wherein said common electrical connection is connected to said first and second power supply means.
Claim 16
Dependent Claim
56 words
A drive circuit according to claim 8 wherein said main inductor is connected in circuit with said main electrode and said secondary inductors are connected in circuit with respective ones of said secondary electrodes to form resonant circuits, said common electrical connection being connected to a point intermediate said main inductor and said secondary switching devices.
Claim 17
Dependent Claim
197 words
A drive circuit for a capacitive light emitting film display wherein a phosphor film is interposed between a plurality of main electrodes on one side and a plurality of groups of secondary electrodes on the other side, each of said groups being associated with a respective one of said main electrodes, comprising main inductors connected in circuit with respective ones of said main electrodes, secondary inductors connected in circuit with respective ones of said secondary electrodes, power supply means for applying an electrical potential to different ones of said main electrodes, said power supply means including main switching devices connected in circuit with respective ones of said main electrodes; power supply means for applying an electrical potential to said secondary electrodes, said last mentioned power supply means including secondary switching devices connected in circuit with respective ones of said secondary electrodes whereby, when any of said main switching devices and any of said secondary switching devices associated with a said last mentioned main switching device are simultaneously turned off, energy stored in respective ones of said inductors will be transferred to respective ones of said electrodes to cause light emission; said inductors having a common electrical connection.
Claim 18
Dependent Claim
197 words
A drive circuit for a capacitive light emitting film display wherein a phosphor film is interposed between a plurality of main electrodes on one side and a plurality of groups of secondary electrodes on the other side, each of said groups being associated with a respective one of said main electrodes, comprising main inductors connected in circuit with respective ones of said main electrodes, secondary inductors connected in circuit with respective ones of said secondary electrodes, power supply means for applying an electrical potential to different ones of said main electrodes, said power supply means including main switching devices connected in circuit with respective ones of said main electrodes; power supply means for applying an electrical potential to said secondary electrodes, said last mentioned power supply means including secondary switching devices connected in circuit with respective ones of said secondary electrodes whereby, when any of said main switching devices and any of said secondary switching devices associated with a said last mentioned main switching device are simultaneously turned off, energy stored in respective ones of said inductors will be transferred to respective ones of said electrodes to cause light emission; said inductors having a common electrical connection.
Claim 19
Dependent Claim
18 words
A device according to claim 14 comprising means for alternately applying different voltage potentials to said secondary inductors.
Claim 20
Dependent Claim
25 words
A device according to claim 14 comprising means for changing said voltage potential applied to said secondary inductors when said switching devices are turned off.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-09-02 | 1978-03-04 | 1978-09-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-09-02 | 1982-03-04 | 1982-09-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-09-02 | 1986-03-04 | 1986-09-03 | $7700.00 | Window Closed / Lapsed |