Patent US4549216A successfully refreshed from Google Patents.
US4549216A
Expired / Lapsed
US
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Focusing voltage output circuit for cathode ray tube
Assignee: Hitachi Ltd
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Filing: 1983-12-14
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Granted: 1985-10-22
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Expires: 2003-12-14
Abstract
Abstract In a focusing voltage output circuit for a cathode ray tube, a variable impedance circuit is connected in series with a variable resistor for adjustment of focusing voltage. The impedance of the variable impedance circuit is changed in response to a video luminance signal or a beam current to change the focusing voltage so as to optimize the focus tracking characteristic.
Inventors
- 👤 Ikuo Yuki
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 15:45
CPC Classifications
H; H04; H04N; H04N3/00; H04N3/10; H04N3/16; H04N3/26
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
100 words
In a focusing voltage output circuit for a cathode ray tube wherein focusing voltage derived from a fly-back transformer having a first output terminal for anode voltage of the cathode ray tube and a second output terminal for the focusing voltage, the improvement which comprises: an input terminal for receiving a video signal or a beam current flowing in said cathode ray tube; and a variable impedance circuit connected between said second output terminal and a focusing voltage output terminal wherein said variable impedance circuit changes its impedance with a magnitude of said input signal applied to said input terminal.
Claim 2
Dependent Claim
100 words
In a focusing voltage output circuit for a cathode ray tube wherein focusing voltage derived from a fly-back transformer having a first output terminal for anode voltage of the cathode ray tube and a second output terminal for the focusing voltage, the improvement which comprises: an input terminal for receiving a video signal or a beam current flowing in said cathode ray tube; and a variable impedance circuit connected between said second output terminal and a focusing voltage output terminal wherein said variable impedance circuit changes its impedance with a magnitude of said input signal applied to said input terminal.
Claim 3
Dependent Claim
43 words
A focusing voltage output circuit according to claim 1, further comprising a variable resistor for adjusting the focusing voltage wherein said variable resister and said variable impedance circuit are connected in series between said second output terminal and said focusing voltage output terminal.
References Cited (Backward Citations)
US4198592A
Cited
US4316128A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1988-10-21 | 1989-04-22 | 1989-10-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-10-21 | 1993-04-22 | 1993-10-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-10-21 | 1997-04-22 | 1997-10-22 | $7700.00 | Window Closed / Lapsed |