US5243262A
Expired / Lapsed
US
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Method and apparatus for compensating alternating electrical fields present at the front surface of a cathode picture tube
Assignee: Tandberg Data Storage AS
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Filing: 1991-12-17
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Granted: 1993-09-07
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Expires: 2011-12-17
Abstract
Abstract A method and apparatus for compensating the alternating electrical fields present at the front surface of a cathode ray picture tube wherein the high-voltage signal supplied to the high-voltage terminal of the tube is tapped to extract an alternating voltage signal therefrom, and the alternating voltage signal is inverted and amplified and then applied to a suitable external electrode placed in the proximity of the picture tube. The external electrode can be a framing band, an aquadag region or a ring electrode, among other things. Furthermore, combination of these electrodes can be employed.
Inventors
- 👤 Tor Moen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 21:58
CPC Classifications
H; H01; H01J; H01J29/00; H01J29/003; H01J29/98; H01J2229/00; H01J2229/0007; H01J2229/0015
Claims Analysis
Total Claims: 28
Claim 1
Independent Claim
111 words
A method of compensating the alternating electrical field resulting at the front surface of a cathode ray picture tube having an EHT terminal to which a high-voltage signal is supplied from a high-voltage signal generator, comprising the steps of: (a) sensing an alternating voltage signal at the EHT terminal; (b) inverting and amplifying the sensed signal; (c) transmitting the inverted and amplified sensed signal to at least one electrode positioned in the immediate vicinity of the picture tube to generate a compensating field; and (d) compensating the alternating electrical field at the front surface of the picture tube with the compensating field generated by said transmitted inverted and amplified sensed signal.
Claim 2
Independent Claim
111 words
A method of compensating the alternating electrical field resulting at the front surface of a cathode ray picture tube having an EHT terminal to which a high-voltage signal is supplied from a high-voltage signal generator, comprising the steps of: (a) sensing an alternating voltage signal at the EHT terminal; (b) inverting and amplifying the sensed signal; (c) transmitting the inverted and amplified sensed signal to at least one electrode positioned in the immediate vicinity of the picture tube to generate a compensating field; and (d) compensating the alternating electrical field at the front surface of the picture tube with the compensating field generated by said transmitted inverted and amplified sensed signal.
Claim 3
Dependent Claim
20 words
The method of claim 1 comprising the further step of controlling the gain of the amplification of the sensed signal.
Claim 4
Dependent Claim
25 words
The method of claim 1 comprising the further step of filtering the sensed signal to remove any DC voltage signals prior to inversion and amplification.
Claim 5
Dependent Claim
25 words
The method claim 1 comprising the step of transmitting the inverted and amplified sensed signal to an aquadag region of the cathode ray picture tube.
Claim 6
Dependent Claim
34 words
The method of claim 1 wherein the step of sensing comprises tapping into a connecting line coupling the high-voltage signal generator and the EHT terminal by means of a sleeve surrounding the connecting line.
Claim 7
Dependent Claim
43 words
The method of claim 1 wherein the step of transmitting the inverted and amplified sensed signal to at least one electrode comprises transmitting the inverted and amplified sensed signal to two or more electrodes positioned in the immediate vicinity of the picture tube.
Claim 8
Dependent Claim
120 words
An arrangement for compensating the alternating electrical field resulting at the front surface of a cathode ray picture tube having an EHT terminal to which a high-voltage signal is supplied by a high-voltage signal generator electrically connected thereto, comprising: (a) at least one electrode positioned externally in the immediate proximity of the picture tube; (b) a signal tap between the high voltage signal generator and the EHT terminal of the picture tube; and (c) an inverting amplifier having an input coupled to the signal tap and an output coupled to the electrode so that the alternating electrical field at the front surface of the cathode ray tube is compensated by the inverse of a signal present at the EHT terminal.
Claim 9
Dependent Claim
120 words
An arrangement for compensating the alternating electrical field resulting at the front surface of a cathode ray picture tube having an EHT terminal to which a high-voltage signal is supplied by a high-voltage signal generator electrically connected thereto, comprising: (a) at least one electrode positioned externally in the immediate proximity of the picture tube; (b) a signal tap between the high voltage signal generator and the EHT terminal of the picture tube; and (c) an inverting amplifier having an input coupled to the signal tap and an output coupled to the electrode so that the alternating electrical field at the front surface of the cathode ray tube is compensated by the inverse of a signal present at the EHT terminal.
Claim 10
Dependent Claim
14 words
The arrangement of claim 7 wherein the gain of the inverting amplifier is controllable.
Claim 11
Dependent Claim
19 words
The arrangement of claim 7 wherein the external electrode is positioned outside the front surface of the picture tube.
Claim 12
Dependent Claim
21 words
The arrangement of claim 9 wherein the external electrode that at least partially surrounds the front surface of the picture tube.
Claim 13
Dependent Claim
22 words
The arrangement of claim 7 wherein the external electrode comprises a ring electrode arranged outside the front surface of the picture tube.
Claim 14
Dependent Claim
18 words
The arrangement of claim 7 wherein the external electrode comprises a framing band that surrounds the picture tube.
Claim 15
Dependent Claim
17 words
The arrangement of claim 7 wherein the external electrode comprises an aquadag region of the picture tube.
Claim 16
Dependent Claim
35 words
The arrangement of claim 7 wherein the signal tap comprises a metallic sleeve that at least partially surrounds a connecting line coupling the high-voltage signal generator to the EHT high-voltage terminal of the picture tube.
Claim 17
Dependent Claim
13 words
The arrangement of claim 14 wherein the metallic sleeve is made of copper.
Claim 18
Dependent Claim
33 words
The arrangement of claim 7 further comprising a low-pass filter positioned between the high-voltage signal generator and the EHT terminal, to which low pass filter the input of the inverting amplifier is connected.
Claim 19
Dependent Claim
49 words
The arrangement of claim 16 wherein the input of the inverting amplifier is coupled to the low-pass filter by means of a capacitor and an output of the inverting amplifier is coupled to the output of the low-pass filter to provide feedback to the input of the inverting amplifier.
Claim 20
Dependent Claim
30 words
The arrangement of claim 7 comprising two or more electrodes positioned externally in the immediate vicinity of the picture tube to which the output of the inverting amplifier is coupled.
Claim 21
Dependent Claim
92 words
A cathode ray picture tube construction comprising: a cathode picture tube having an EHT high-voltage signal terminal; a high-voltage signal generator coupled to the EHT terminal; at least one external electrode positioned in the immediate proximity of the picture tube; and an inverting amplifier having an input coupled to an output of the high-voltage signal generator and an output coupled to the external electrode such that a signal present at the EHT terminal is inverted and used to compensate an alternating signal present at the front of the cathode ray picture tube.
Claim 22
Dependent Claim
92 words
A cathode ray picture tube construction comprising: a cathode picture tube having an EHT high-voltage signal terminal; a high-voltage signal generator coupled to the EHT terminal; at least one external electrode positioned in the immediate proximity of the picture tube; and an inverting amplifier having an input coupled to an output of the high-voltage signal generator and an output coupled to the external electrode such that a signal present at the EHT terminal is inverted and used to compensate an alternating signal present at the front of the cathode ray picture tube.
Claim 23
Dependent Claim
29 words
The cathode ray picture tube construction of claim 19 further comprising a filter coupled between the input of the inverting amplifier and the output of the high-voltage signal generator.
Claim 24
Dependent Claim
26 words
The cathode ray picture tube construction of claim 19 wherein the external electrode comprises a ring electrode arranged outside the front surface of the picture tube.
Claim 25
Dependent Claim
21 words
The cathode ray picture tube of claim 19 wherein the external electrode comprises a framing band that surrounds the picture tube.
Claim 26
Dependent Claim
21 words
The cathode ray picture tube of the claim 19 wherein the external electrode comprises an aquadag region of the picture tube.
Claim 27
Dependent Claim
43 words
The cathode ray picture tube of claim 19 further comprising a metallic sleeve positioned about a connecting line that couples the output of the high-voltage signal generator to the EHT terminal, the input of the inverting amplifier being coupled to the metallic sleeve.
Claim 28
Dependent Claim
33 words
The cathode ray picture tube of claim 19 comprising two or more external electrodes positioned in the immediate vicinity of the picture tube to which the output of the inverting amplifier is coupled.
References Cited (Backward Citations)
US4636911A
Cited
US5151635A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1996-09-06 | 1997-03-08 | 1997-09-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-09-06 | 2001-03-08 | 2001-09-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-09-06 | 2005-03-08 | 2005-09-07 | $7700.00 | Window Closed / Lapsed |