DETERMINING TOUCH DATA FOR ONE OR MORE OBJECTS ON A TOUCH SURFACE
First Claim
1. A method in a touch-sensing apparatus, said apparatus comprising a light transmissive panel that defines a touch surface and an opposite surface, a light source arrangement for providing sheets of light inside the panel, wherein each sheet comprises light that propagates by internal reflection between the touch surface and the opposite surface from an incoupling site to an outcoupling site, said apparatus further comprising a light sensor arrangement for detecting light reaching the outcoupling site, wherein the touch-sensing apparatus is configured such that one or more objects touching the touch surface causes a local attenuation of at least two sheets of light, said method comprising the steps of:
- obtaining at least one projection signal which is indicative of a spatial distribution of light within said outcoupling site;
processing said at least one projection signal for identification of signal profiles representing said attenuation;
identifying, based on the signal profiles, one or more candidate touch areas on the touch surface;
processing said at least one projection signal to reconstruct a two-dimensional distribution of signal values within said one or more candidate touch areas; and
determining touch data for the or each object by processing the reconstructed signal values within the candidate touch areas.
1 Assignment
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Accused Products
Abstract
A touch-sensing apparatus comprises a light transmissive panel, in which sheets of light are propagated by internal reflection between a touch surface and an opposite surface from an incoupling site to an outcoupling site. The touch-sensing apparatus is configured such that objects touching the touch surface cause a local attenuation of at least two sheets of light. A light sensor arrangement is optically connected to the outcoupling site to measure transmitted light energy. A data processor is connected to the light sensor arrangement and configured to execute a touch determination process. The process operates on at least one projection signal which is indicative of a spatial distribution of light within the outcoupling site.
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Citations
22 Claims
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1. A method in a touch-sensing apparatus, said apparatus comprising a light transmissive panel that defines a touch surface and an opposite surface, a light source arrangement for providing sheets of light inside the panel, wherein each sheet comprises light that propagates by internal reflection between the touch surface and the opposite surface from an incoupling site to an outcoupling site, said apparatus further comprising a light sensor arrangement for detecting light reaching the outcoupling site, wherein the touch-sensing apparatus is configured such that one or more objects touching the touch surface causes a local attenuation of at least two sheets of light, said method comprising the steps of:
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obtaining at least one projection signal which is indicative of a spatial distribution of light within said outcoupling site; processing said at least one projection signal for identification of signal profiles representing said attenuation; identifying, based on the signal profiles, one or more candidate touch areas on the touch surface; processing said at least one projection signal to reconstruct a two-dimensional distribution of signal values within said one or more candidate touch areas; and determining touch data for the or each object by processing the reconstructed signal values within the candidate touch areas. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
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20. A device for determining touch data for one or more objects on a touch surface included in a touch-sensing apparatus, said touch-sensing apparatus comprising a light transmissive panel that defines the touch surface and an opposite surface, a light source arrangement for providing sheets of light inside the panel, wherein each sheet comprises light that propagates by internal reflection between the touch surface and the opposite surface from an incoupling site to an outcoupling site, a light sensor arrangement for detecting light reaching the outcoupling site, wherein the touch-sensing apparatus is configured such that each object touching the touch surface locally attenuates at least two sheets of light, said device comprising:
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an element for obtaining at least one projection signal which is indicative of a spatial distribution of light within said outcoupling site; an element for processing said at least one projection signal for identification of signal profiles representing said attenuation; an element for identifying, based on the signal profiles, one or more candidate touch areas on the touch surface; an element for processing said at least one projection signal to reconstruct a two-dimensional distribution of signal values within said one or more candidate touch areas; and an element for determining touch data for the or each object by processing the reconstructed signal values within the candidate touch areas.
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21. (canceled)
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22. A method in a touch-sensing apparatus, said apparatus comprising a light transmissive panel that defines a touch surface and an opposite surface, a light source arrangement for providing sheets of light inside the panel, wherein each sheet comprises light that propagates by internal reflection between the touch surface and the opposite surface from an incoupling site to an outcoupling site, said apparatus further comprising a light sensor arrangement for detecting light reaching the outcoupling site, wherein the touch-sensing apparatus is configured such that one or more objects touching the touch surface causes a local attenuation of at least two sheets of light, said method comprising the steps of:
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obtaining at least one projection signal which is indicative of a spatial distribution of light within said outcoupling site; processing said at least one projection signal for identification of signal profiles representing said attenuation; determining, for each signal profile, an attenuation path across the touch surface, wherein the attenuation path has a width which is determined based on the signal profile; identifying, as a function of a set of thus-determined attenuation paths, one or more candidate touch areas on the touch surface; and determining touch data for the or each object based on the candidate touch areas.
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Specification