US3579225A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Light probe circuit for persistent screen display system
Assignee: RCA Corp
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Filing: 1969-10-15
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Granted: 1971-05-18
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Expires: 1989-10-15
Abstract
Abstract The light sensed by a light ''''probe'''' or ''''pen'''' during each field displayed on a persistent screen causes a signal to be stored for a duration which is a fraction of the field time. The placing of the probe in a light sensing position causes a second signal of a duration at least equal to one field time to be stored and which starts at a time after the pen is placed in its light sensing position at which the next field starts. A circuit responsive to the concurrent presence of both stored signals produces an output pulse which may be employed to signal the computer associated with the light probe.
Inventors
- 👤 Robert John Clark
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 00:53
CPC Classifications
G; G06; G06F; G06F3/00; G06F3/01; G06F3/02
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
180 words
In a system having a cathode ray tube and a light probe which is activated when the area of the screen at which it is pointing produces light at greater than a given intensity, and in which the screen has sufficient persistence that an area energized by the electron beam continues to produce light at a level greater than said given intensity for not more than one field time, the improvement comprising, in combination: means responsive to the sensing of light by said light probe during each field time for storing a first signal only for the interval, during each field time, between the time light is sensed and the end of the field time; means responsive to the placing of said light probe in its light sensing position for storing a second signal having a duration at least equal to one field time and starting at the time, after the probe is placed in said position, at which the next field starts; and means responsive to the concurrent presence of said two stored signals for generating an output signal.
Claim 2
Dependent Claim
180 words
In a system having a cathode ray tube and a light probe which is activated when the area of the screen at which it is pointing produces light at greater than a given intensity, and in which the screen has sufficient persistence that an area energized by the electron beam continues to produce light at a level greater than said given intensity for not more than one field time, the improvement comprising, in combination: means responsive to the sensing of light by said light probe during each field time for storing a first signal only for the interval, during each field time, between the time light is sensed and the end of the field time; means responsive to the placing of said light probe in its light sensing position for storing a second signal having a duration at least equal to one field time and starting at the time, after the probe is placed in said position, at which the next field starts; and means responsive to the concurrent presence of said two stored signals for generating an output signal.
Claim 3
Dependent Claim
176 words
In a system having a display with a persistent screen and a light probe which is activated when the area of the screen at which it is pointing produces light at greater than a given intensity, and in which the screen has sufficient persistence that an area energized during one field time continues to produce light at a level greater than said given intensity for not more than one additional field time, the improvement comprising, in combination: means responsive to the sensing of light by said light probe during each field time for storing a first signal only for a fraction of each field time, starting at the time light is sensed; means responsive to the placing of said light probe in its light sensing position for storing a second signal having a duration of at least one field time and starting at the time, after the probe is placed in said position, at which the next field starts; and means responsive to the concurrent presence of said two stored signals for generating an output signal.
Claim 4
Dependent Claim
176 words
In a system having a display with a persistent screen and a light probe which is activated when the area of the screen at which it is pointing produces light at greater than a given intensity, and in which the screen has sufficient persistence that an area energized during one field time continues to produce light at a level greater than said given intensity for not more than one additional field time, the improvement comprising, in combination: means responsive to the sensing of light by said light probe during each field time for storing a first signal only for a fraction of each field time, starting at the time light is sensed; means responsive to the placing of said light probe in its light sensing position for storing a second signal having a duration of at least one field time and starting at the time, after the probe is placed in said position, at which the next field starts; and means responsive to the concurrent presence of said two stored signals for generating an output signal.
Claim 5
Dependent Claim
44 words
The combination claimed in claim 2, said means responsive to the sensing of light comprising a flip-flop which is set in response to the sensing of light and which is reset at the end of the field time in which the light is sensed.
Claim 6
Dependent Claim
52 words
The combination claimed in claim 2, said means responsive to the placing of said light probe in its light sensing position comprising a flip-flop which is set at the next field time after the probe is placed in the light sensing position and is reset no sooner than one field time later.
Claim 7
Dependent Claim
22 words
The combination claimed in claim 2, said means responsive to the concurrent presenCe of said two stored signals comprising an AND gate.
Claim 8
Dependent Claim
149 words
In a system having a display with a persistent screen and a light probe which is activated when the area of the screen at which it is pointing produces light at greater than a given intensity, and in which the screen has sufficient persistence that an area energized during one field time continues to produce light at a level greater than said given intensity for not more than one additional field time, the improvement comprising, in combination: means responsive to the sensing of light by said light probe during two successive field times, after the light probe has been placed in its light sensing position, for producing an output signal; and means responsive to the sensing of light by said light probe during less than two successive field times, after the light probe has been placed in said light sensing position, for preventing the production of said output signal.
Claim 9
Dependent Claim
149 words
In a system having a display with a persistent screen and a light probe which is activated when the area of the screen at which it is pointing produces light at greater than a given intensity, and in which the screen has sufficient persistence that an area energized during one field time continues to produce light at a level greater than said given intensity for not more than one additional field time, the improvement comprising, in combination: means responsive to the sensing of light by said light probe during two successive field times, after the light probe has been placed in its light sensing position, for producing an output signal; and means responsive to the sensing of light by said light probe during less than two successive field times, after the light probe has been placed in said light sensing position, for preventing the production of said output signal.
Claim 10
Dependent Claim
27 words
The combination claimed in claim 6, including means responsive to said output signal for signalling said system to display a selected frame of video on said display.
Claim 11
Dependent Claim
132 words
An information display system comprising in combination; a persistent screen; means for displaying on said screen a page of index characters and for refreshing the displayed characters at a rate sufficient to cause each character to remain visible during the intervals between which it is refreshed; means including a light pen for causing to be displayed on said screen in response to the receipt by the light pen of light from one of said characters, at the time said character is being refreshed, a frame of information called for by said character; and means for preventing the last-named means from displaying such a frame of information in response to the receipt by the light pen of light from one of said characters at a time other than when it is being refreshed.
Claim 12
Dependent Claim
132 words
An information display system comprising in combination; a persistent screen; means for displaying on said screen a page of index characters and for refreshing the displayed characters at a rate sufficient to cause each character to remain visible during the intervals between which it is refreshed; means including a light pen for causing to be displayed on said screen in response to the receipt by the light pen of light from one of said characters, at the time said character is being refreshed, a frame of information called for by said character; and means for preventing the last-named means from displaying such a frame of information in response to the receipt by the light pen of light from one of said characters at a time other than when it is being refreshed.
References Cited (Backward Citations)
US3189889A
Cited
US3440638A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-05-17 | 1974-11-16 | 1975-05-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-05-17 | 1978-11-16 | 1979-05-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-05-17 | 1982-11-16 | 1983-05-18 | $7700.00 | Window Closed / Lapsed |