Touch screen signal processing
First Claim
1. A touch detection method comprising:
- directing light from a plurality of sources across a surface of a screen, the screen configured for a user to touch and view an image on or through;
imaging (i) light traveling in a space above the front surface of said screen and (ii) a mirror image comprising light reflected from the surface of said screen using at least two cameras located so as not to receive direct light from the plurality of sources;
processing outputs of said cameras to detect the level of reflected light from an object in the space above the front surface of said screen and the level of light from said mirror image; and
determining a location of said object from the processed outputs of said cameras based on triangulation techniques.
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Accused Products
Abstract
A touch screen which uses light sources at one or more edges of the screen which directs light across the surface of the screen and at least two cameras having electronic outputs located at the periphery of the screen to receive light from said light sources. A processor receives the outputs of said cameras and employs triangulation techniques to determine the location of an object proximate to said screen. Detecting the presence of an object includes detecting at the cameras the presence or absence of direct light due to the object, using a screen surface as a mirror and detecting at the cameras the presence or absence of reflected light due to an object. The light sources may be modulated to provide a frequency band in the output of the cameras.
75 Citations
21 Claims
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1. A touch detection method comprising:
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directing light from a plurality of sources across a surface of a screen, the screen configured for a user to touch and view an image on or through; imaging (i) light traveling in a space above the front surface of said screen and (ii) a mirror image comprising light reflected from the surface of said screen using at least two cameras located so as not to receive direct light from the plurality of sources; processing outputs of said cameras to detect the level of reflected light from an object in the space above the front surface of said screen and the level of light from said mirror image; and determining a location of said object from the processed outputs of said cameras based on triangulation techniques. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A touch detection system comprising:
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a screen configured for a user to touch and view an image on or through; a plurality of light sources at one or more edges of said screen and configured to direct light across the surface of said screen; at least two cameras having outputs, each camera located at the periphery of said screen and positioned to image light traveling in the space above the front of said screen and light reflected from said screen, the light reflected from said screen representing a mirror image of the space above the front of said screen; and at least one processor configured to employ triangulation techniques and said outputs to determine whether the processed outputs indicate the presence of an object proximate to said screen and, if so, the location of said object; wherein the location comprises the distance of said object from the front of said screen. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20, 21)
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Specification