US4404499A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Circuit for minimizing edge hooking in television camera pickup tubes
Assignee: Ampex Corp
•
Filing: 1981-03-30
•
Granted: 1983-09-13
•
Expires: 2001-03-30
Abstract
Abstract Selected additional voltages are utilized to modify the respective horizontal and vertical sawtooth waveforms which generate the horizontal and vertical electron beam scans in a photoelectric tube. The added voltages are selectively applied during the respective horizontal and vertical blanking intervals, whereby the speed of the scan is doubled, tripled, etc., during the blanking intervals. Since the time available during blanking is still the same, increasing the speed of the beam scan causes the beam to scan correspondingly further into the non-scanned target portion. Thus, corresponding greater distances into the surrounding target are discharged which, in turn, circumvents charge bleeding into the active picture area, thereby precluding edge hooking.
Inventors
- 👤 John O. Ryan
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 16:03
CPC Classifications
H; H04; H04N; H04N23/00; H04N23/40
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
88 words
A circuit for minimizing edge hooking in a photoelectric tube having a scanning electron beam and a scanned active picture area within a non-scanned tube target area, wherein the scanning electron beam describes a horizontal and vertical scan raster across the active picture area in response to means for generating horizontal and vertical sawtooth waveforms, comprising the combination of; overscan voltage means integral with the means for generating sawtooth waveforms for selectively increasing the velocity of the electron beam scan only during the horizontal and vertical blanking intervals.
Claim 2
Dependent Claim
88 words
A circuit for minimizing edge hooking in a photoelectric tube having a scanning electron beam and a scanned active picture area within a non-scanned tube target area, wherein the scanning electron beam describes a horizontal and vertical scan raster across the active picture area in response to means for generating horizontal and vertical sawtooth waveforms, comprising the combination of; overscan voltage means integral with the means for generating sawtooth waveforms for selectively increasing the velocity of the electron beam scan only during the horizontal and vertical blanking intervals.
Claim 3
Dependent Claim
45 words
The circuit of claim 1 wherein; the overscan voltage means applies a selected voltage waveform to the sawtooth waveforms during the conventional horizontal and vertical blanking pulse intervals to provide the selective increase in velocity of scan during the respective horizontal and vertical blanking intervals.
Claim 4
Dependent Claim
24 words
The circuit of claim 2 wherein; the scan velocity during the blanking interval is greater than the scan velocity during the active picture interval.
Claim 5
Dependent Claim
39 words
The circuit of claim 3 wherein the overscan voltage means includes; means for supplying DC pulses to the means for generating the sawtooth waveforms during the respective blanking intervals to increase the slope of the waveform during these intervals.
Claim 6
Dependent Claim
44 words
The circuit of claim 4 wherein the overscan voltage means includes; a selected resistance coupled to the input of the means for generating the sawtooth waveforms; and DC pulse generating means coupled to the resistance and responsive to the horizontal and vertical blanking pulses.
Claim 7
Dependent Claim
36 words
The circuit of claim 4 wherein the overscan voltage means includes; a waveform generator responsive to the blanking pulses; and adder means coupled to the waveform generator and to the means for generating the sawtooth waveforms.
Claim 8
Dependent Claim
37 words
The circuit of claim 6 wherein; the waveform generator includes means for supplying a sinewave of selected configuration to the sawtooth waveform during the blanking interval to increase the velocity of the beam scan during the interval.
Claim 9
Independent Claim
92 words
A method for minimizing edge hooking in a photoelectric tube having a scanning electron beam and a scanned active picture area within a non-scanned tube target, wherein charge buildup in the non-scanned portion circumjacent the scanned active picture area causes charge bleeding from the former into the latter, comprising the steps of; generating horizontal and vertical sawtooth waveforms in response to a respective DC input voltage; and adding additional overscan voltage to the sawtooth waveforms during respective blanking intervals to selectively increase the slope of the sawtooth ramp during the blanking interval.
Claim 10
Independent Claim
92 words
A method for minimizing edge hooking in a photoelectric tube having a scanning electron beam and a scanned active picture area within a non-scanned tube target, wherein charge buildup in the non-scanned portion circumjacent the scanned active picture area causes charge bleeding from the former into the latter, comprising the steps of; generating horizontal and vertical sawtooth waveforms in response to a respective DC input voltage; and adding additional overscan voltage to the sawtooth waveforms during respective blanking intervals to selectively increase the slope of the sawtooth ramp during the blanking interval.
Claim 11
Dependent Claim
29 words
The method of claim 8 wherein the step of adding further comprises; applying blanking pulses to the DC input pulses in symmetry therewith to provide the increase in slope.
Claim 12
Dependent Claim
53 words
The method of claim 8 wherein the step of adding further comprises the steps of; producing selected DC pulses corresponding to the overscan voltages during the respective horizontal and vertical blanking intervals; applying the selected DC pulses to the respective DC input voltage to provide the increase in slope during the blanking intervals.
Claim 13
Dependent Claim
55 words
The method of claim 8 wherein the step of adding further comprises the steps of; producing selected voltage sinewaves corresponding to the overscan voltages during the respective horizontal and vertical blanking intervals; and adding the selected voltage sinewaves to respective horizontal and vertical sawtooth waveforms during the blanking intervals to provide the increase in slope.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1986-09-12 | 1987-03-14 | 1987-09-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-09-12 | 1991-03-14 | 1991-09-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-09-12 | 1995-03-14 | 1995-09-13 | $7700.00 | Window Closed / Lapsed |