Touch sensing using shadow and reflective modes
First Claim
1. A method of operating a touch panel system for detecting one or more objects in proximity with a touchable surface of a touch panel, the method comprising:
- scanning at least a portion of the touch panel to measure a level of ambient infrared radiation using at least one infrared sensor;
switching to a shadow mode of operation if a level of ambient infrared radiation exceeds a first threshold;
switching to a reflective mode of operation if the level of ambient infrared radiation does not exceed both the first threshold and a second threshold;
determining that a battery level is below a predetermined limit while the level of ambient infrared radiation exceeds the second threshold and not the first threshold;
switching to the shadow mode of operation after the battery level drops below the predetermined limit; and
switching to the reflective mode of operation after the battery level rises above the predetermined limit.
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Accused Products
Abstract
A touch panel is described which uses at least one infrared source and an array of infrared sensors to detect objects which are in contact with, or close to, the touchable surface of the panel. The panel may be operated in both reflective and shadow modes, in arbirary per-pixel combinations which change over time. For example, if the level of ambient infrared is detected and if that level exceeds a threshold, shadow mode is used for detection of touch events over some or all of the display. If the threshold is not exceeded, reflective mode is used to detect touch events. The touch panel includes an infrared source and an array of infrared sensors.
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Citations
10 Claims
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1. A method of operating a touch panel system for detecting one or more objects in proximity with a touchable surface of a touch panel, the method comprising:
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scanning at least a portion of the touch panel to measure a level of ambient infrared radiation using at least one infrared sensor; switching to a shadow mode of operation if a level of ambient infrared radiation exceeds a first threshold; switching to a reflective mode of operation if the level of ambient infrared radiation does not exceed both the first threshold and a second threshold; determining that a battery level is below a predetermined limit while the level of ambient infrared radiation exceeds the second threshold and not the first threshold; switching to the shadow mode of operation after the battery level drops below the predetermined limit; and switching to the reflective mode of operation after the battery level rises above the predetermined limit. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A touch panel system for detecting one or more objects in proximity with a touchable surface of the touch panel system, the touch panel system comprising:
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a touch panel having integrated therein infrared sensors distributed throughout the touch panel parallel to the touchable surface; at least one infrared source configured to illuminate objects through the touchable surface; and a control element arranged to; scan at least a portion of the touch panel to measure a level of ambient infrared radiation; switch to a shadow mode of operation if a level of ambient infrared radiation exceeds a first threshold; switch to a reflective mode of operation if the level of ambient infrared radiation does not exceed both the first threshold and a second threshold; determine that a battery level is below a predetermined limit while the level of ambient infrared radiation exceeds the second threshold and not the first threshold; switch to the shadow mode of operation after the battery level drops below the predetermined limit; and switch to the reflective mode of operation after the battery level rises above the predetermined limit. - View Dependent Claims (8, 9, 10)
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Specification