US3665453A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Character generator employing pulsed beam interrogation of matrix
Assignee: COMPUFOTO Inc
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Filing: 1970-06-01
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Granted: 1972-05-23
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Expires: 1990-06-01
Abstract
Abstract A cathode ray tube character generator suitable for computer output microfilming employs pulsed beam interrogation of a selected sector of a character matrix according to a predetermined pattern. There is shown a tube having a phosphor plate producing stationary light spots for effectively dissecting a character on a matrix transparency that is external of the tube. The pattern of stationary light pulses is produced with high speed phosphor and digitally implemented deflection system, with each stationary light spot being judged on a digital on or off basis. High quality character generation at suitable rates results. The system provides improved signal to noise ratio for the signal produced from the character matrix; e.g. with a cathode ray tube light source, the system decreases noise which is realized to be related to microscopic variations in the phosphor surface. An implementation of the control system is shown as essentially a logic network, with transistor switching of various resistors in and out of the deflection coil circuit according to predetermined progression, with the light spot pattern being developed e.g., on a left to right, down, right to left down basis. Incremental shift of the deflection system from one setting to the next occurs with the beam blanked, and no change in setting occurs when the beam is unblanked. A cathode ray tube system identical to the character generator is used as the display tube for the microfilm camera, both controlled by a master clock, with delay of the pulses to the display tube. In both systems the beam unblank pulses are correlated with the clock pulses, and the falling edge of the clock pulses controls the next incremented setting of the deflection network.
Inventors
- 👤 Asger T Nielsen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 20:25
CPC Classifications
G; G06; G06K; G06K15/00; G06K15/02; G06K15/12; G06K15/1233
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
269 words
In a character generator comprising a cathode ray tube having an electron beam source, a character selection deflection system for directing the beam generally toward a selected one of a set of sectors of a beam receiving surface, said surface adapted to produce emissions, a character generating deflection system for directing the beam over the area of said selected sector, a character matrix having character forms positioned for exposure to emissions from corresponding sectors of said beam receiving surface, an emission-responsive element including circuitry for detecting the emissions from said surface as modified by the selected character form of said matrix, and a recording device operable in timed relation with said character generating deflection system and controlled by said responsive element to record the character, the improvement comprising a control system associated with said character generating deflection system for causing pulsed interrogation of the selected character form on said matrix, said control system including means operative after a sector has been selected for incrementally changing the input signal to said character generating deflection system to provide a series of predetermined deflection positions in number and spacing sufficient, together, to effectively cover the area of said sector, means for maintaining said electron beam blanked during change in said character generating deflection system from one position to the next in said series, and means for maintaining constant the position of said character generating deflection system while said beam is unblanked, said control system thereby adapted to cause each position on said sector to be exposed only to a stationary beam that forms an emission pulse for detection by said responsive device.
Claim 2
Dependent Claim
269 words
In a character generator comprising a cathode ray tube having an electron beam source, a character selection deflection system for directing the beam generally toward a selected one of a set of sectors of a beam receiving surface, said surface adapted to produce emissions, a character generating deflection system for directing the beam over the area of said selected sector, a character matrix having character forms positioned for exposure to emissions from corresponding sectors of said beam receiving surface, an emission-responsive element including circuitry for detecting the emissions from said surface as modified by the selected character form of said matrix, and a recording device operable in timed relation with said character generating deflection system and controlled by said responsive element to record the character, the improvement comprising a control system associated with said character generating deflection system for causing pulsed interrogation of the selected character form on said matrix, said control system including means operative after a sector has been selected for incrementally changing the input signal to said character generating deflection system to provide a series of predetermined deflection positions in number and spacing sufficient, together, to effectively cover the area of said sector, means for maintaining said electron beam blanked during change in said character generating deflection system from one position to the next in said series, and means for maintaining constant the position of said character generating deflection system while said beam is unblanked, said control system thereby adapted to cause each position on said sector to be exposed only to a stationary beam that forms an emission pulse for detection by said responsive device.
Claim 3
Dependent Claim
139 words
The character generator of claim 1 wherein saiD beam-receiving surface is a phosphor plate located at the end of said cathode ray tube, adapted to emit a spot of light when struck by said beam, said character matrix comprises a transparency located outside of said tube in a position to be illuminated by said light emissions at said various positions, and said responsive element is positioned on the side of said transparency opposite to that of said cathode ray tube and arranged to receive said light emission as modified by the character form selected by said beam, the cathode ray tube having characteristic variations in light spot intensity depending upon the position of said beam, and said responsive element having a detection threshold to enable detection of the light spot over the range of its characteristic variations in intensity.
Claim 4
Dependent Claim
76 words
The character generator of claim 1 wherein said deflection system comprises an X-deflection coil and circuit and a Y-character generating deflection coil and circuit, said control system comprises, for each deflection coil, an array of resistors, and a series of electronic switches arranged to insert and remove said resistors from supplying current to the respective deflection coil in accordance with a predetermined progression thereby to alter the current in the respective coil in a stepwise manner.
Claim 5
Dependent Claim
127 words
The character generator of claim 1 in which said character generating deflection system comprises a first deflection coil having a predetermined first number of settings and a second coil having a predetermined second number of settings, said control system including means for holding the setting for said first coil constant while causing the setting for the second coil to proceed through its full series of values, means thereupon to increase by one position the setting for said first coil, and means thereupon to cause the setting for the second coil to proceed in reverse order through its full series, thereby to effectively produce a series of left to right, down, right to left, down cycles of incremental progressions for covering the character form of the character matrix.
Claim 6
Dependent Claim
52 words
The character generator of claim 3 wherein said resistances and switches of each circuit define a deflection network capable of being switched into said circuit in accordance with a binary progression, a pulse generator and a binary counter arranged to count generated pulses and control said network in accordance with the count.
Claim 7
Dependent Claim
124 words
The character generator of claim 1 wherein said recorder comprises a cathode ray display tube having a character generating deflection system and a control system having a series of settings for pulsed operation of a stationary beam, a master clock controlling the timing of the advancing of the settings of the character generating deflection systems of both said tubes, means delaying the clock pulses applied to said display tube, an enable switch connected to be enabled by signals from said emission responsive element and said delayed clock pulses arranged to produce an unblank pulse on said display tube whenever said enable switch is activated by said responsive element, with said unblank pulse timed to occur prior to change in said character generating deflection settings.
Claim 8
Dependent Claim
37 words
The character generator of claim 1 in combination with a microfilm recorder, said character generator and recorder including means adapted to be controlled by signals representing the output of a computer to enable computer output microfilm recording.
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) | 1975-05-23 | 1975-11-22 | 1976-05-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-05-23 | 1979-11-22 | 1980-05-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-05-23 | 1983-11-22 | 1984-05-23 | $7700.00 | Window Closed / Lapsed |