Scheme for determining position of surface contact of cathode ray tube screen
First Claim
1. A system having a display device wherein an electron beam scans a screen associated with said display device, said system comprisingmeans for detecting, from the exterior of said display device, said electron beam as it scans past a first spot and a second spot on said screen, said first spot being in a predetermined fixed location on said screen, and said second spot being in a variable location different from said predetermined fixed location, andmeans for determining a time difference between the detection of said electron beam as it scans past the first and second spots.
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Accused Products
Abstract
A touch-screen scheme is employed in an arrangement wherein an inquiry and a choice of responses thereto are displayed on a CRT screen. In accordance with this scheme, a first touch-screen device is held against a predetermined spot on the screen. A selection is made by holding a second touch-screen device against the area of the screen corresponding to the desired response. When the electron beam which scans the CRT screen sweeps across the first and second touch-screen devices at different times, the two device generate two signal outputs. The touch-position or the selection is determined based on the time difference between the two signal outputs.
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Citations
34 Claims
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1. A system having a display device wherein an electron beam scans a screen associated with said display device, said system comprising
means for detecting, from the exterior of said display device, said electron beam as it scans past a first spot and a second spot on said screen, said first spot being in a predetermined fixed location on said screen, and said second spot being in a variable location different from said predetermined fixed location, and means for determining a time difference between the detection of said electron beam as it scans past the first and second spots.
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10. A system having a CRT screen which is scanned by an electron beam, said system comprising
means for displaying a plurality of choices on said CRT screen, each choice being associated with a different CRT screen location, means for selecting one of said choices, said selecting means being in close proximity to a first CRT screen location associated with the selected choice and also in close proximity to a second CRT screen location not associated with any of said plurality of choices. and means for providing an output signal representative of the selected choice, said providing means being responsive to said electron beam passing said first and second CRT screen locations.
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18. A method for use in a system having a display device wherein an electron beam scans a screen associated with said display device, said method comprising the steps of
detecting, from the exterior of said display device, said electron beam as it scans past a first spot and a second spot on said screen, said first spot being in a predetermined fixed location on said screen, and said second spot being in a variable location different from said predetermined fixed location, and determining a time difference between the detection of said electron beam as it scans past the first and second spots.
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27. A method for use in a system having a CRT screen which is scanned by an electron beam, said method comprising the steps of
displaying a plurality of choices on said CRT screen, each choice being associated with a different CRT screen location, selecting one of said choices, using a selecting apparatus which is disposed in close proximity to a first CRT screen location associated with the selected choice and and which is also disposed in close proxmity to a second CRT screen location not associated with any of said plurality of choices, and providing an output signal representative of the selected choice in response to said electron beam passing said first and second CRT screen locations.
Specification