Scanning system for touch screen keyboards
First Claim
1. A touch screen keyboard system for a display panel, comprising:
- a plurality of spaced-apart light emitters positioned along at least one edge of said display panel;
a plurality of spaced-apart light detectors positioned along an edge of said display panel opposite said light emitters;
power means for selectively energizing each of said light emitters in response to an activation signal applied to each of said light emitters;
detector means for enabling an output form at least one predetermined light detector while a respective light emitter is being energized, and for determining whether light from the energized light emitter is being received by said enabled light detector; and
control means for generating a pseudo random activation signal for each of said light emitters thereby energizing said light emitters in the pseudo random manner to reduce the probability that an external light source operating in close proximity will operate in synchronism and thus interfere with said touch screen.
1 Assignment
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Accused Products
Abstract
A touch screen control system having a plurality of light emitter and detector pairs positioned on opposite sides of a touch screen display. The emitters and detectors are controlled by a microprocessor-based control system that energizes each of the light emitters in a pseudorandom manner. Before each light emitter is energized, the intensity of ambient light is measured by its associated light detector, and the ambient temperature is also measured by a temperature sensor. The intensity at which the light emitter is then energized is controlled as a function of ambient light and temperature. The control system generates a bitmap identifying beams from each light emitter to its associated detector that are obscured during each of several scans of the light emitter/detector pairs. In order to reject false receptions of light from an obscured light emitter beam, the control system processes the bitmap through a predetermined voting procedure. The control system is thus able to minimize the effect of interfering light sources on the performance of the touch screen.
86 Citations
19 Claims
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1. A touch screen keyboard system for a display panel, comprising:
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a plurality of spaced-apart light emitters positioned along at least one edge of said display panel; a plurality of spaced-apart light detectors positioned along an edge of said display panel opposite said light emitters; power means for selectively energizing each of said light emitters in response to an activation signal applied to each of said light emitters; detector means for enabling an output form at least one predetermined light detector while a respective light emitter is being energized, and for determining whether light from the energized light emitter is being received by said enabled light detector; and control means for generating a pseudo random activation signal for each of said light emitters thereby energizing said light emitters in the pseudo random manner to reduce the probability that an external light source operating in close proximity will operate in synchronism and thus interfere with said touch screen. - View Dependent Claims (2, 3, 4)
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5. A touch screen keyboard system for a display panel, comprising:
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a plurality of spaced-apart light emitters positioned along at least one edge of said display panel to form part of said touch screen keyboard system; a plurality of spaced-apart light detectors positioned along an edge of said display panel opposite said light emitters to form part of said touch screen keyboard system; power control means for selectively energizing each of said light emitters in response to an activation signal applied to each of said light emitters, said power control means energizing each of said light emitters at an intensity corresponding to a respective intensity control signal; detector means for enabling an output from at least one predetermined light detector while a respective light emitter is being energized, and for determining whether light from the energized light emitter is being received by said light detector; and compensation means for generating each of said intensity control signals as a function of the intensity of ambient light so that the intensity of light emitted by said light emitters is a function of the intensity of ambient light. - View Dependent Claims (6, 7, 8, 9, 10, 11, 12, 13)
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14. A touch screen keyboard system for a display panel, comprising:
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a plurality of spaced-apart light emitters positioned along at least one edge of said display panel; a plurality of spaced-apart light detectors positioned along an edge of said display panel opposite said light emitters; power means for selectively energizing each of said light emitters in response to an activation signal applied to each of said light emitters; detector means for enabling at least one predetermined light detector while a respective light emitter is being energized, and for determining whether light from the energized light emitter is being received by said enabled light detector; control means for straining said light emitter/light detector pairs by generating an activation signal for each of said light emitters; memory means connected to said detector means to record whether light from each of said light emitters is being received by a respective light detector during a predetermined number of scans of said light emitter/light detector pairs; and processing means operatively connected to said memory means for providing an indication that an area of said display panel corresponding to a predetermined light emitter/light detector pair has been activated only if light from the light emitter in said pair has not been received by the respective light detector in said pair during a plurality of successive scans of said light emitter/light detector pairs.
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15. A method of scanning a touch screen keyboard system having a plurality of spaced-apart light emitters positioned along at least one edge of a display panel and a plurality of spaced-apart light detectors positioned along an edge of said display panel opposite said light emitters, said method comprising:
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pseudo randomly energizing each of said light emitters, and determining if light from each energized light emitters is being received by a corresponding light detector so that the probability that a plurality of touch screen keyboard systems operating in close proximity will operate in synchronism and thus interfere with each other is reduced. - View Dependent Claims (16)
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17. A method of scanning a touch screen keyboard system having a plurality of spaced-apart light emitters positioned along at least one edge of a display panel and a plurality of spaced-apart light detectors positioned along an edge of said display panel opposite said light emitters, said method comprising:
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selectively energizing each of said light emitters at an intensity that is a function of the intensity of ambient light; enabling an output from at least one predetermined light detector while a respective light emitter is being energized; and determining whether light from the energized light emitter is being received by said enabled light detector. - View Dependent Claims (18)
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19. A method of scanning a touch screen keyboard system having a plurality of spaced-apart light emitters positioned along at least one edge of a display panel and a plurality of spaced-apart light detectors positioned along an edge of said display panel opposite said light emitters, said method comprising:
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selectively energizing each of said light emitters; enabling an output from at least one predetermined light detector while a respective light emitter is being energized; determining whether light from the energized light emitter is being received by said enabled light detector; recording whether light from each of said light emitters is being received by a respective light detector during a predetermined number of scans of said light emitter/light detector pairs; and providing an indication that an area of said display panel corresponding to a predetermined light emitter/light detector pair has been activated only if light from the light emitter in said pair has not been received by the respective light detector in said pair during a plurality of successive scans of said light emitter/light detector pairs.
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Specification