Patent US3976990A successfully refreshed from Google Patents.
US3976990A
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US
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Apparatus and method for offsetting selected characters of a character display
Assignee: AT&T Teletype Corp
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Filing: 1974-12-20
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Granted: 1976-08-24
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Expires: 1994-12-20
Abstract
Abstract An apparatus is disclosed for displaying subscript and superscript characters on the screen of a cathode ray tube. The encoded characters are selectively read from a memory which also provides two extended level outputs relating to the subscript and superscript features. In response to the readout of a superscript character from memory, a superscript signal, at the related extended memory output, is fed to an amplifier which, in turn, drives a superscript coil positioned about the neck of the cathode ray tube. This superscript coil generates a flux which reacts with the flux generated by the tube's vertical deflection coil during readout of the selected character thereby raising the position of that character on the screen. Correspondingly, a subscript signal at the related extended memory output results in the generation of a magnetic flux which reacts the vertical deflection coil field during readout of the selected character thereby lowering the position of that character on the screen.
Inventors
- 👤 Gary R. Haak
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 23:50
CPC Classifications
G; G09; G09G; G09G1/00; G09G1/04; G09G5/00; G09G5/22; G09G5/30; Y; Y10; Y10S; Y10S400/00; Y10S400/904
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
248 words
An apparatus for displaying a plurality of characters at a plurality of possible predetermined locations on a display screen comprising: readout means providing an encoded character signal serving to determine a character to be displayed at one of said predetermined locations on the screen, means for providing an offset signal in response to the presence of a selected encoded character from said readout means; means responsive to said offset signal for shifting the location of the display of said selected character from its predetermined row location on the display screen so as to render visually distinct said selected character with respect to at least some of the normally displayed characters in the related row; said display screen forming a portion of a cathode ray tube and the electron beam being in the form of a cathode ray beam impinging the screen of the cathode ray tube, a main vertical deflection coil having a predetermined inductance, the magnetic field of which controls said cathode ray beam during the generation of a character row upon the cathode ray tube screen; and said character offset means including a minor vertical deflection coil having an inductance of a value less than said main vertical deflection coil inductance, said minor vertical deflection coil producing a second relatively constant magnetic field interacting with the magnetic field created by said main vertical deflection coil during the writing of said selected character so as to offset said selected character from its related row of corresponding characters.
Claim 2
Independent Claim
248 words
An apparatus for displaying a plurality of characters at a plurality of possible predetermined locations on a display screen comprising: readout means providing an encoded character signal serving to determine a character to be displayed at one of said predetermined locations on the screen, means for providing an offset signal in response to the presence of a selected encoded character from said readout means; means responsive to said offset signal for shifting the location of the display of said selected character from its predetermined row location on the display screen so as to render visually distinct said selected character with respect to at least some of the normally displayed characters in the related row; said display screen forming a portion of a cathode ray tube and the electron beam being in the form of a cathode ray beam impinging the screen of the cathode ray tube, a main vertical deflection coil having a predetermined inductance, the magnetic field of which controls said cathode ray beam during the generation of a character row upon the cathode ray tube screen; and said character offset means including a minor vertical deflection coil having an inductance of a value less than said main vertical deflection coil inductance, said minor vertical deflection coil producing a second relatively constant magnetic field interacting with the magnetic field created by said main vertical deflection coil during the writing of said selected character so as to offset said selected character from its related row of corresponding characters.
Claim 3
Dependent Claim
26 words
The apparatus of claim 1 wherein said second magnetic field aids the magnetic field produced by said main vertical deflection coil thereby producing a superscript character.
Claim 4
Dependent Claim
26 words
The apparatus of claim 1 wherein said second magnetic field opposes the magnetic field produced by said main vertical deflection coil thereby producing a subscript character.
Claim 5
Dependent Claim
49 words
The apparatus of claim 2 which further includes a subscript vertical deflection coil having an inductance of a value less than said main vertical deflection coil and producing a third magnetic field which opposes the magnetic field generated by said main vertical deflection coil thereby producing a subscript character.
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) | 1979-08-24 | 1980-02-23 | 1980-08-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-08-24 | 1984-02-23 | 1984-08-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-08-24 | 1988-02-23 | 1988-08-24 | $7700.00 | Window Closed / Lapsed |