Patent US4035834A successfully refreshed from Google Patents.
US4035834A
Expired / Lapsed
US
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Beam landing indicator for color cathode ray tube
Assignee: Panasonic Corp of North America
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Filing: 1976-04-12
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Granted: 1977-07-12
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Expires: 1996-04-12
Abstract
Abstract A system for quickly and easily making accurate purity and yoke adjustments of a color cathode ray tube of a television receiver utilizes a separate oscilloscope display of vector beam landing errors. Photocells, provided with filters to cause them to be responsive to selected colors, are placed in front of the cathode ray tube to produce output pulses once for each vertical scan of the beam in the cathode ray tube. A rotational beam landing shift at 15 Hertz is produced by a vertical and horizontal deflection field generated in synchronism with the vertical deflection signal of the cathode ray tube to cause a stepped deflection of the beam in a diamond pattern of up, right, down and left for each successive vertical field. Light variations sensed by the photocell pickup are converted to a 15 Hertz signal which is combined with a 15 Hertz reference signal to control the dot location on the oscilloscope display of the vector beam landing error. Purity adjustments and yoke adjustments then are made on the cathode ray tube by observing the oscilloscope display.
Inventors
- 👤 Anthony M. Drury
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 19:02
CPC Classifications
H; H04; H04N; H04N17/00; H04N17/04
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
104 words
A beam landing indicator system for a color cathode ray tube including in combination: first means for creating an auxiliary magnetic field for deflecting the electron beam in the cathode ray tube; second means coupled with said first means for changing said magnetic field according to a predetermined pattern; light sensing means located to sense light emitted from phosphors of one color from the cathode ray tube; and an oscilloscope, the deflection coils of which are coupled in circuit with said second means and said light sensing means for producing a vector indication of the beam landing adjustment of the color cathode ray tube.
Claim 2
Dependent Claim
104 words
A beam landing indicator system for a color cathode ray tube including in combination: first means for creating an auxiliary magnetic field for deflecting the electron beam in the cathode ray tube; second means coupled with said first means for changing said magnetic field according to a predetermined pattern; light sensing means located to sense light emitted from phosphors of one color from the cathode ray tube; and an oscilloscope, the deflection coils of which are coupled in circuit with said second means and said light sensing means for producing a vector indication of the beam landing adjustment of the color cathode ray tube.
Claim 3
Dependent Claim
38 words
The combination according to claim 1 wherein said second means causes the auxiliary magnetic field to be rotated according to said predetermined pattern and at a submultiple of the vertical scanning frequency of the color cathode ray tube.
Claim 4
Dependent Claim
42 words
The combination according to claim 1 further including control means coupling said light sensing means with said second means for effecting the rotation of the auxiliary magnetic field in synchronism with the scanning of the electron beam of the cathode ray tube.
Claim 5
Dependent Claim
33 words
The combination according to claim 3 wherein said rotation of the auxiliary magnetic field is effected at a submultiple of the vertical scanning frequency of the electron beam in said cathode ray tube.
Claim 6
Dependent Claim
128 words
The combination according to claim 1 wherein said light sensing means is responsive to light of a single predetermined color and is located approximately at the center of the display screen of the color cathode ray tube for producing output pulses at the vertical scanning rate of the electron beam in the cathode ray tube, said output pulses having an amplitude corresponding to the illumination of the phosphor dots on the screen of the cathode ray tube of said predetermined color, and further including means coupling said light sensing means with said second means for effecting a stepped rotation of the auxiliary magnetic field in synchronism with the scanning of the electron beam of the color cathode ray tube and at a submultiple of the vertical scanning frequency.
Claim 7
Dependent Claim
30 words
The combination according to claim 1 wherein said means for creating an auxiliary magnetic field comprises horizontal and vertical deflection coils mounted in close proximity to said light sensing means.
Claim 8
Independent Claim
120 words
A method of sensing and displaying electron beam landing errors of a color television cathode ray tube, comprising the steps of: subjecting the electron beam of the cathode ray tube to a rotational beam landing shift at a predetermined frequency; sensing variations in the emitted light from phosphors of a predetermined color on the face of the cathode ray tube; converting the sensed light variations to a signal of said predetermined frequency; combining said converted signal at said predetermined frequency with a reference signal at said predetermined frequency to produce vector indicia of the magnitude and direction of beam landing error; and displaying said vector indicia of beam landing error as a mark on the screen of a display oscilloscope.
Claim 9
Independent Claim
120 words
A method of sensing and displaying electron beam landing errors of a color television cathode ray tube, comprising the steps of: subjecting the electron beam of the cathode ray tube to a rotational beam landing shift at a predetermined frequency; sensing variations in the emitted light from phosphors of a predetermined color on the face of the cathode ray tube; converting the sensed light variations to a signal of said predetermined frequency; combining said converted signal at said predetermined frequency with a reference signal at said predetermined frequency to produce vector indicia of the magnitude and direction of beam landing error; and displaying said vector indicia of beam landing error as a mark on the screen of a display oscilloscope.
Claim 10
Dependent Claim
34 words
The method according to claim 7 wherein said rotational beam landing shift is produced at a frequency of 15 Hertz, wherein the sensed emitted light variations also are converted to a 15 Hertz signal.
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) | 1980-07-11 | 1981-01-10 | 1981-07-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-07-11 | 1985-01-10 | 1985-07-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-07-11 | 1989-01-10 | 1989-07-12 | $7700.00 | Window Closed / Lapsed |