Patent US4340910A successfully refreshed from Google Patents.
US4340910A
Expired / Lapsed
US
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CRT Spot suppression circuit
Assignee: GTE Sylvania Inc
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Filing: 1979-09-24
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Granted: 1982-07-20
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Expires: 1999-09-24
Abstract
Abstract In a CRT system having a cathode coupled to a source of first potential voltage and a control grid biased negatively with respect to the cathode, means coupled between a source of second potential voltage and control grid for superimposing negative-going transitions in the second potential voltage upon the control grid so as to suppress the appearance of spots upon the face of the CRT subsequent to the de-energization of that system.
Inventors
- 👤 Silverio A. Valdes
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 23:18
CPC Classifications
H; H04; H04N; H04N3/00; H04N3/10; H04N3/16; H04N3/24
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
92 words
In a cathode ray tube system having a reference electrode coupled to a source of first potential voltage and a control electrode biased negatively with respect to the first potential voltage, spot-suppressing means coupled to a source of second potential voltage and the control electrode for superimposing negative-going transitions in the second potential voltage upon the control electrode so as to suppress spots on the face of the cathode ray tube system when that system is de-energized, said spot-suppressing means comprising breakdown means coupled between the reference electrode and the control electrode.
Claim 2
Dependent Claim
92 words
In a cathode ray tube system having a reference electrode coupled to a source of first potential voltage and a control electrode biased negatively with respect to the first potential voltage, spot-suppressing means coupled to a source of second potential voltage and the control electrode for superimposing negative-going transitions in the second potential voltage upon the control electrode so as to suppress spots on the face of the cathode ray tube system when that system is de-energized, said spot-suppressing means comprising breakdown means coupled between the reference electrode and the control electrode.
Claim 3
Dependent Claim
22 words
Spot-suppressing means as defined in claim 1 comprising a capacitance coupled between the source of second potential voltage and the control electrode.
Claim 4
Dependent Claim
20 words
Spot-suppressing means as defined in claim 2 further comprising diode means coupled between the control electrode and a reference potential.
Claim 5
Dependent Claim
15 words
Spot-suppressing means as defined in claim 3 wherein said breakdown means comprises a zener diode.
References Cited (Backward Citations)
DE2423726A1
Cited
US4056758A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1985-07-19 | 1986-01-18 | 1986-07-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-07-19 | 1990-01-18 | 1990-07-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-07-19 | 1994-01-18 | 1994-07-20 | $7700.00 | Window Closed / Lapsed |