Photoelastic touch-sensitive screen
First Claim
1. A touch-sensitive device comprisinga screen,means for generating and directing polarized signals having at least a predetermined polarization into said screen, said screen causing changes in the polarization of ones of said polarized signals which pass through a point on said screen at which a force is applied, andmeans responsive to said ones of said signals having changes in said polarization for determining the location of said point at which said force is applied on said screen.
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Accused Products
Abstract
A touch-sensitive device comprising a photoelastic screen having light reflecting edges and a unique light emitting/receiving module placed at two of the four corners of the screen advantageously determines the location at which a force is applied to the screen. Circularly and linearly polarized light focused into the photoelastic screen by the modules reflects off the edges of the screen and is returned to the modules where it is absorbed by a circular polarizer. The polarization of light passing through a point at which the screen is touched is changed thereby allowing these rays or signals to pass through each module'"'"'s absorber. The location as well as the magnitude and direction of the force imparted to the screen by the touch is then determined from the changes in the signals that pass through the absorber.
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Citations
20 Claims
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1. A touch-sensitive device comprising
a screen, means for generating and directing polarized signals having at least a predetermined polarization into said screen, said screen causing changes in the polarization of ones of said polarized signals which pass through a point on said screen at which a force is applied, and means responsive to said ones of said signals having changes in said polarization for determining the location of said point at which said force is applied on said screen.
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11. A touch-sensitive device comprising
a screen, means for focusing polarized signals from a source into said screen, said polarized signals having at least a predetermined polarization, said screen causing changes in the polarization of ones of said polarized signals when they pass through a point on said screen at which a force is applied, module means for receiving said ones of said polarized signals and for outputting signals indicative of the extent of said changes, said ones of said polarized signals entering said receiving means at an angle, and means responsive to changes in the level of said outputted signals for determining said angle and for determining the location of said applied force on said screen as a function of said angle.
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20. A method of locating a point on a body of photoelastic material at which a force is applied comprising the steps of
generating and directing polarized signals having at least a predetermined polarization into said photoelastic material, said material causing changes in the polarization of said signals which pass through said point, and determining the location of said point on said material as a function of said changes.
Specification