US3898381A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Television display apparatus including a beam current clamping control circuit
Assignee: US Philips Corp
•
Filing: 1974-01-10
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Granted: 1975-08-05
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Expires: 1994-01-10
Abstract
Abstract A beam current clamping control circuit in which in case of a too large deviation of the desired value of the field frequency measured beam current an accelerated correction of this deviation is effected.
Inventors
- 👤 Willem Hendrik Amsen
- 👤 Paulus Joseph Maria Hovens
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 16:57
CPC Classifications
H; H04; H04N; H04N5/00; H04N5/14; H04N5/141
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
161 words
Television display apparatus including a beam current clamping control circUit having a beam current measuring circuit operable by a pulse generator and coupled to a television display tube for measuring, during at least part of a line scan time of a field blanking time a beam current reference level to be corrected, a level insertion circuit for inserting the reference level during the measuring time into a video signal to be applied to the television display tube and a level correction circuit coupled to an output of the measuring circuit and to a control electrode of the television display tube, the measuring circuit including a threshold circuit and a storage circuit, characterized in that the threshold circuit is a circuit which applies a signal to an output thereof when a too large beam current occurs, said output being coupled to an operation signal input of a circuit means for extending the charge correction time of the storage circuit per field period.
Claim 2
Dependent Claim
161 words
Television display apparatus including a beam current clamping control circUit having a beam current measuring circuit operable by a pulse generator and coupled to a television display tube for measuring, during at least part of a line scan time of a field blanking time a beam current reference level to be corrected, a level insertion circuit for inserting the reference level during the measuring time into a video signal to be applied to the television display tube and a level correction circuit coupled to an output of the measuring circuit and to a control electrode of the television display tube, the measuring circuit including a threshold circuit and a storage circuit, characterized in that the threshold circuit is a circuit which applies a signal to an output thereof when a too large beam current occurs, said output being coupled to an operation signal input of a circuit means for extending the charge correction time of the storage circuit per field period.
Claim 3
Dependent Claim
38 words
Television display apparatus as claimed in claim 1, characterized in that the circuit extending the charge correction time is a circuit means for increasing the measuring frequency, whereby a greater number of measurements per unit time is effected.
Claim 4
Dependent Claim
62 words
Television display apparatus as claimed in claim 1, characterized in that the circuit extending the charge correction time is a change-over switch a first input of which is coupled to an input of the measuring circuit, a second input is coupled to a beam current independent charging circuit coupled to a supply source and an output is coupled to the storage circuit.
Claim 5
Dependent Claim
30 words
Television display apparatus as claimed in claim 1, characterized in that the pulse generator includes a counting circuit having a feedback which can be switched on by the threshold circuit.
Claim 6
Dependent Claim
160 words
A beam current clamping control circuit for a television display tube comprising a beam current measuring circuit means for measuring during at least part of a line scan time of a field blanking time a beam current reference level to be corrected, a pulse generator coupled to said measuring circuit, a level insertion circuit means coupled to said pulse generator for inserting the reference level during the measuring time into a video signal to be applied to the television display tube, a level correction circuit coupled to an output of the measuring circuit, the measuring circuit including a threshold circuit means for coupling to said tube for applying a signal to an output thereof when a beam current above a selected value occurs, a storage circuit, and a circuit means for extending the charge correction time of the storage circuit per field period having an input coupled to said threshold circuit output and an output coupled to said storage circuit.
Claim 7
Dependent Claim
160 words
A beam current clamping control circuit for a television display tube comprising a beam current measuring circuit means for measuring during at least part of a line scan time of a field blanking time a beam current reference level to be corrected, a pulse generator coupled to said measuring circuit, a level insertion circuit means coupled to said pulse generator for inserting the reference level during the measuring time into a video signal to be applied to the television display tube, a level correction circuit coupled to an output of the measuring circuit, the measuring circuit including a threshold circuit means for coupling to said tube for applying a signal to an output thereof when a beam current above a selected value occurs, a storage circuit, and a circuit means for extending the charge correction time of the storage circuit per field period having an input coupled to said threshold circuit output and an output coupled to said storage circuit.
References Cited (Backward Citations)
US3558817A
Cited
US3602642A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-08-04 | 1979-02-03 | 1979-08-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-08-04 | 1983-02-03 | 1983-08-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-08-04 | 1987-02-03 | 1987-08-05 | $7700.00 | Window Closed / Lapsed |