Method and device for detecting touch pad input
First Claim
1. A method for determining a location of an object substantially touching a touch pad, the touch pad having a plurality of surrounding edges, said method comprising:
- providing a light sheet comprising a plurality of light beams oriented to propagate in an air space over the touch pad such that the light sheet is partially blocked by the object when the object intrudes into the air space, wherein light intensity of the light sheet is spatially varying in such a manner that the light intensity of the partially blocked light sheet is dependent upon the location of the touching object, and wherein the light beams are provided by a first light providing structure disposed adjacent to a first surrounding edge and a second light providing structure disposed adjacent to a second surrounding edge opposite to the first surrounding edge, and wherein each of the first and second light providing structures has a longitudinal axis and further comprises a light source for providing a source beam along the longitudinal axis, and a plurality of partially reflecting surfaces distributed along the longitudinal axis to partially reflect the source beam for providing the light beams in the light sheet such that light intensity of the light beams varies along the longitudinal axis;
disposing a first light detecting structure behind the second light providing structure for measuring the light intensity of the light beams provided by the first light providing structure, wherein the measured light intensity is reduced when the light sheet is partially blocked by the object;
disposing a second light detecting structure behind the first light providing structure for further measuring the light intensity of the light beams provided by the second light providing structure, wherein the further measured light intensity is reduced when the light sheet is partially blocked by the object; and
calculating the location of the object based on the measured reduced intensity and the further measured reduced intensity.
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Accused Products
Abstract
A method and system for determining the location of an object touching a touch pad. A light source is used to provide a light beam and a plurality of reflecting surfaces are disposed along an edge of the touch pad to partially reflect the light beam in order to provide a light sheet over the touch pad, such that the reflected intensity varies monotonously along the edge. A detector structure is disposed on the opposite edge to measure the light intensity of the light sheet, part of which is blocked when the object touches the touch pad. The reduction in the measured light intensity is used to calculate the location of the touching object in one direction. A second light sheet and a corresponding detector structure can be used to determine the location of the touching object in a different direction.
80 Citations
21 Claims
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1. A method for determining a location of an object substantially touching a touch pad, the touch pad having a plurality of surrounding edges, said method comprising:
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providing a light sheet comprising a plurality of light beams oriented to propagate in an air space over the touch pad such that the light sheet is partially blocked by the object when the object intrudes into the air space, wherein light intensity of the light sheet is spatially varying in such a manner that the light intensity of the partially blocked light sheet is dependent upon the location of the touching object, and wherein the light beams are provided by a first light providing structure disposed adjacent to a first surrounding edge and a second light providing structure disposed adjacent to a second surrounding edge opposite to the first surrounding edge, and wherein each of the first and second light providing structures has a longitudinal axis and further comprises a light source for providing a source beam along the longitudinal axis, and a plurality of partially reflecting surfaces distributed along the longitudinal axis to partially reflect the source beam for providing the light beams in the light sheet such that light intensity of the light beams varies along the longitudinal axis; disposing a first light detecting structure behind the second light providing structure for measuring the light intensity of the light beams provided by the first light providing structure, wherein the measured light intensity is reduced when the light sheet is partially blocked by the object; disposing a second light detecting structure behind the first light providing structure for further measuring the light intensity of the light beams provided by the second light providing structure, wherein the further measured light intensity is reduced when the light sheet is partially blocked by the object; and calculating the location of the object based on the measured reduced intensity and the further measured reduced intensity. - View Dependent Claims (2, 3, 4, 5)
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6. A light detecting system for use in conjunction with a touch pad for determining a location of an object substantially touching the touch pad, the touch pad having a plurality of surrounding edges, said system comprising:
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a light sheet comprising a plurality of light beams oriented to propagate in an air space over the touch pad such that the light sheet is partially blocked by the object when the object intrudes into the air space, wherein light intensity of the light sheet is spatially varying in such a manner that the blocked intensity is dependent upon the location of the object, and wherein the light beams are provided by a first light providing structure disposed adjacent to a first surrounding edge and a second light providing structure disposed adjacent to a second surrounding edge opposite to the first surrounding edge, and wherein each of the first and second light providing structures has a longitudinal axis and further comprises a light source for providing a source beam along the longitudinal axis, and a plurality of partially reflecting surfaces distributed along the longitudinal axis to partially reflect the source beam for providing the light beams in the light sheet such that light intensity of the light beams varies along the longitudinal axis; a first light detecting structure disposed behind the second light providing structure for measuring the light intensity of the light beams provided by the first light providing structure trough the second light providing structure for providing a signal indicative of a first measured light intensity, wherein the first measured light intensity is reduced when the light sheet is partially blocked by the object; a second light detecting structure disposed behind the first light providing structure for measuring the light intensity of the light beams provided by the second light providing structure through the first light providing structure for providing a further signal indicative of a second measured light intensity, wherein the second measured light Intensity is reduced when the light sheet is partially blocked by the object; and a computation module, responsive to the signal and the further signal, for calculating the location of the object based on the first measured reduced intensity and the second measured reduced intensity. - View Dependent Claims (7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21)
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Specification