Pressure-sensing touch system utilizing total-internal reflection
First Claim
1. A pressure-sensing touch system for sensing an amount of pressure at a touch location of a touch event caused by a finger having a fingerprint, comprising:
- a single-layer transparent sheet having a monolithic body with a top surface, a bottom surface, and a perimeter that includes first and second edges, wherein the touch event occurs directly on the top surface at a touch event location, with the top surface having a surface roughness in the range from 100 microns to 300 microns either peak-to-valley or root mean square to enhance an optical contact between the fingerprint and the top surface;
at least one light source operably arranged either at the first edge or at the bottom surface adjacent the first edge of the single-layer transparent sheet and that emits light that is coupled into the single-layer transparent sheet so that the light travels only within the monolithic body of the single-layer transparent sheet via total internal reflection from the top and bottom surfaces only until the touch event and the optical contact between the fingerprint and the top surface at the touch event location causes a portion of the light to be scattered out of the single-layer transparent sheet, thereby defining an attenuated light beam that travels only within the monolithic body of the single-layer transparent sheet; and
at least one detector operably disposed either at the first edge, at the second edge or at the bottom surface adjacent the second edge of the single-layer transparent sheet to generate a detector electrical signal having a signal strength representative of a detected intensity of the attenuated light beam traveling only within the single-layer transparent sheet and that is incident upon the at least one detector, wherein the optical contact of the touch event causes a change in the detected light intensity that corresponds to a change in pressure applied at the touch event location.
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Accused Products
Abstract
A pressure-sensing touch system that utilizes total-internal reflection of light is disclosed. The touch system includes a transparent sheet having a surface. At least one light source and at least one detector are operably arranged relative to the transparent sheet respective to transmit light through the sheet and to detect the transmitted light. A touch event at the top surface of the transparent sheet causes light to scatter from the transparent sheet, thereby changing the amount of light received at the detector. Since the amount of scattered light generated at the touch event location is a function of the applied pressure at the touch event, the change in the detector signal is used to determine the relative amount of applied pressure. Embodiments that include multiple waveguides and channel waveguides, as well as force-sensing devices, are also disclosed.
122 Citations
19 Claims
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1. A pressure-sensing touch system for sensing an amount of pressure at a touch location of a touch event caused by a finger having a fingerprint, comprising:
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a single-layer transparent sheet having a monolithic body with a top surface, a bottom surface, and a perimeter that includes first and second edges, wherein the touch event occurs directly on the top surface at a touch event location, with the top surface having a surface roughness in the range from 100 microns to 300 microns either peak-to-valley or root mean square to enhance an optical contact between the fingerprint and the top surface; at least one light source operably arranged either at the first edge or at the bottom surface adjacent the first edge of the single-layer transparent sheet and that emits light that is coupled into the single-layer transparent sheet so that the light travels only within the monolithic body of the single-layer transparent sheet via total internal reflection from the top and bottom surfaces only until the touch event and the optical contact between the fingerprint and the top surface at the touch event location causes a portion of the light to be scattered out of the single-layer transparent sheet, thereby defining an attenuated light beam that travels only within the monolithic body of the single-layer transparent sheet; and at least one detector operably disposed either at the first edge, at the second edge or at the bottom surface adjacent the second edge of the single-layer transparent sheet to generate a detector electrical signal having a signal strength representative of a detected intensity of the attenuated light beam traveling only within the single-layer transparent sheet and that is incident upon the at least one detector, wherein the optical contact of the touch event causes a change in the detected light intensity that corresponds to a change in pressure applied at the touch event location. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A method of determining a relative amount of pressure applied by a finger having a fingerprint applied at a location of a touch event directly on a top surface of a single-layer transparent sheet having a monolithic body with first and second edges and a bottom surface, comprising:
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sending light from at least one light source through the monolithic body of the single-layer transparent sheet by total-internal reflection from the top and bottom surface only, with the top having a surface roughness in the range from 100 microns to 300 microns either peak-to-valley or root mean square to enhance an optical contact between the fingerprint and the top surface, and wherein the light source is arranged either at the first edge or at the bottom surface adjacent the first edge, wherein the light travels only through the monolithic body of the single-layer transparent sheet until the location of the touch event; scattering a portion of the light out of the single-layer transparent sheet by the optical contact between the fingerprint and the top surface, wherein the scattering is in proportion to the relative amount of pressure applied by the fingerprint at the touch location to define an attenuated light beam that travels only within the monolithic body of the single-layer transparent sheet; detecting the attenuated light beam with at least one detector arranged either at the first edge, at the second edge, or at the bottom surface adjacent the second edge, and generating a first detector electrical signal; and determining from the first detector electrical signal the amount of pressure applied by the implement at the location of the touch event. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19)
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Specification