US3816792A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Cathode ray tube high speed electromagnetic deflection system
Assignee: Honeywell Inc
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Filing: 1972-12-21
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Granted: 1974-06-11
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Expires: 1992-12-21
Abstract
Abstract A cathode ray tube dual mode electromagnetic beam deflection control system including an amplifier for driving a deflection coil and means for switching between linear and resonant nonlinear operational modes. In the linear mode, the yoke current is controlled to precisely follow an applied input deflection voltage by comparing the input voltage with a feedback voltage representative of the yoke current. In the non-linear mode, a capacitor is connected in circuit with the coil and the coilcapacitor circuit is simultaneously effectively disconnected from the amplifier output to enable resonant discharge between the coil and capacitor for fast beam retrace.
Inventors
- 👤 J Spencer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 14:36
CPC Classifications
H; H03; H03K; H03K4/00; H03K4/06; H03K4/08; H03K4/48; H03K4/60; H03K4/69; H03K4/693; H03K6/00; H03K6/02
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
272 words
A cathode ray tube dual mode electron beam deflection control system which may be switched to operate in either a linear or a resonant non-linear mode, comprising a deflection coil, an amplifier coupled to the deflection coil and responsive to an input signal representative of desired motion of the beam for supplying current to the deflection coil in linear mode operation, a capacitor switchably coupled in current flowing circuit connection with the deflection coil, bidirectional switching means responsive to an applied mode switching signal for coupling the capacitor in current flowing circuit connection with the deflection coil in non-linear mode operation and decoupling the capacitor from current flowing circuit connection with the deflection coil and the amplifier in linear mode operation, additional switching means responsive to the mode switching signal for effectively disconnecting the amplifier from the deflection coil in non-linear mode operation, and a source of electrical potential, said bidirectional switching means including electrically controllable semiconductor switching means and unidirectional current conductive means connected in parallel and coupled at one end to the capacitor and at the other end to a source of electrical potential with said unidirectional current conductive means poled relative to the electrical potential source so as to be reverse biased in both the linear mode and during an initial part of the non-linear mode for which the semiconductor switching means is in a conductive condition in response to the mode switching signal and thereafter forward biased during the remaining part of the non-linear mode to maintain the capacitor in current flowing circuit connection with the deflection coil irrespective of the conductive state of the semiconductor switching means.
Claim 2
Dependent Claim
272 words
A cathode ray tube dual mode electron beam deflection control system which may be switched to operate in either a linear or a resonant non-linear mode, comprising a deflection coil, an amplifier coupled to the deflection coil and responsive to an input signal representative of desired motion of the beam for supplying current to the deflection coil in linear mode operation, a capacitor switchably coupled in current flowing circuit connection with the deflection coil, bidirectional switching means responsive to an applied mode switching signal for coupling the capacitor in current flowing circuit connection with the deflection coil in non-linear mode operation and decoupling the capacitor from current flowing circuit connection with the deflection coil and the amplifier in linear mode operation, additional switching means responsive to the mode switching signal for effectively disconnecting the amplifier from the deflection coil in non-linear mode operation, and a source of electrical potential, said bidirectional switching means including electrically controllable semiconductor switching means and unidirectional current conductive means connected in parallel and coupled at one end to the capacitor and at the other end to a source of electrical potential with said unidirectional current conductive means poled relative to the electrical potential source so as to be reverse biased in both the linear mode and during an initial part of the non-linear mode for which the semiconductor switching means is in a conductive condition in response to the mode switching signal and thereafter forward biased during the remaining part of the non-linear mode to maintain the capacitor in current flowing circuit connection with the deflection coil irrespective of the conductive state of the semiconductor switching means.
Claim 3
Dependent Claim
39 words
The apparatus of claim 1 wherein the additional switching means comprises a semiconductor switching element connected to the amplifier output stage for setting the output stage in a non-conductive open circuit condition in response to the mode switching signal.
Claim 4
Dependent Claim
59 words
The apparatus of claim 2 including an impedance element connected in series with the deflection coil for providing a voltage representative of the current flowing therethrough to be fed back to the input of the amplifier for comparison with the input signal to maintain the current supplied by the amplifier proportional to the input signal in the linear mode.
Claim 5
Dependent Claim
111 words
The apparatus of claim 1 wherein the semiconductor switching means comprises a transistor having its collector coupled to the capacitor and its emitter coupled to the potential source so as to be responsive to the mode switching signal to operate in a normal forward biased condition during the initial part of the non-linear mode and in a low current gain mode during the remaining part of the non-linear mode as a consequence of high forward bias existing across the transistor base to collector junction at that time whereby current flow through the capacitor and deflection coil then occurs predominantly through the uni-directional current conductive means connected in parallel with the transistor.
Claim 6
Dependent Claim
94 words
The apparatus of claim 4 wherein the amplifier includes a push-pull output stage having first and second sections operating such that the first section controls positive current to the deflection coil for one polarity of the Input signal and the second section controls negative current to the deflection coil for the opposite polarity of the input signal, and further includes additional unidirectional current conductive means connected intermediate the deflection coil and the output of one section for blanking therefrom the high voltage spike produced at the deflection coil upon switching to the non-linear mode.
Claim 7
Dependent Claim
42 words
The apparatus of claim 5 wherein the additional switching means comprises a transistor switching element coupled to the output of the other push-pull section for diverting drive signal therefrom upon being driven into a saturated conductive condition by the mode switching signal.
Claim 8
Dependent Claim
69 words
The apparatus of claim 6 including an impedance connected in series with the deflection coil for providing a voltage representative of the current flowing therethrough to be fed back to the input of the amplifier for comparison with the input signal to derive an error signal equal to the difference between the input and feedback signals for controlling the current supplied by said amplifier means in the linear mode.
References Cited (Backward Citations)
US3541385A
Cited
US3602768A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-06-10 | 1977-12-10 | 1978-06-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-06-10 | 1981-12-10 | 1982-06-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-06-10 | 1985-12-10 | 1986-06-11 | $7700.00 | Window Closed / Lapsed |