Touch surface with a compensated signal profile
First Claim
1. An apparatus for determining a location of at least one object on a touch surface, the apparatus comprising:
- a light transmissive panel defining the touch surface and an opposite surface;
an illumination arrangement configured to introduce light into the light transmissive panel for propagation by internal reflection between the touch surface and the opposite surface;
a light detection arrangement configured to receive the light propagating in the light transmissive panel; and
a processor unit configured to iteratively,determine a current signal profile of light received by the light detection arrangement,update, when a condition is met, a background signal profile of light received by the light detection arrangement,calculate a current compensated signal profile as a function of the background signal profile and the current signal profile, anddetermine, when the at least one object touches the touch surface and thereby attenuates the light propagating in the light transmissive panel, the location as a function of the current compensated signal profile.
1 Assignment
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Accused Products
Abstract
An apparatus, method and computer-readable medium for determining a location of at least one object on a touch surface of a light transmissive panel. The method comprises the steps of: introducing light into the panel for propagation by internal reflection between the touch surface and an opposite surface; receiving the light propagating in the panel; and iteratively i) determining a current signal profile of light received by the light detection arrangement, ii) updating, when a condition is met, a background signal profile of light received by the light detection arrangement, iii) calculating a current compensated signal profile as a function of the background signal profile and the current signal profile and iv) determining, when the object touches the touch surface and thereby attenuates the light propagating in the panel, the location as a function of the compensated signal profile.
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Citations
26 Claims
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1. An apparatus for determining a location of at least one object on a touch surface, the apparatus comprising:
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a light transmissive panel defining the touch surface and an opposite surface; an illumination arrangement configured to introduce light into the light transmissive panel for propagation by internal reflection between the touch surface and the opposite surface; a light detection arrangement configured to receive the light propagating in the light transmissive panel; and a processor unit configured to iteratively, determine a current signal profile of light received by the light detection arrangement, update, when a condition is met, a background signal profile of light received by the light detection arrangement, calculate a current compensated signal profile as a function of the background signal profile and the current signal profile, and determine, when the at least one object touches the touch surface and thereby attenuates the light propagating in the light transmissive panel, the location as a function of the current compensated signal profile. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24)
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25. A method for determining a location of at least one object on a touch surface of a light transmissive panel defining the touch surface and an opposite surface, the method comprising the steps of iteratively:
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determining a current signal profile of light received by a light detection arrangement after propagation in the light transmissive panel by internal reflection between the touch surface and the opposite surface; updating, when a condition is met, a background signal profile of light received by the light detection arrangement; calculating a current compensated signal profile as a function of the background signal profile and the current signal profile; and determining, when the at least one object touches the touch surface and thereby attenuates the light propagating in the light transmissive panel, the location as a function of the current compensated signal profile.
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26. A non-transitory computer-readable medium storing processing instructions that, when executed by a processing unit, cause the processing unit to perform a method for determining a location of at least one object on a touch surface of a light transmissive panel defining the touch surface and an opposite surface, the method comprising:
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determining a current signal profile of light received by a light detection arrangement after propagation in the light transmissive panel by internal reflection between the touch surface and the opposite surface; updating, when a condition is met, a background signal profile of light received by the light detection arrangement; calculating a current compensated signal profile as a function of the background signal profile and the current signal profile; and determining, when the at least one object touches the touch surface and thereby attenuates the light propagating in the light transmissive panel, the location as a function of the current compensated signal profile.
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Specification