Touch screen

Abstract

A method for determining the location of an object on a touch panel is provided. Initially, a pulse of terahertz radiation is transmitted through a touch panel, which formed of a dielectric material such that the pulse generates a evanescent field in a region adjacent to a touch surface of the touch panel. A reflected pulse is generated by an object located within the region adjacent to the touch surface of the touch panel, and a position of the object on the touch surface of the touch panel is triangulated at least in part from the reflected pulse.

1 . A method comprising:
 transmitting a pulse of terahertz radiation through a touch panel formed of a dielectric material such that the pulse generates a evanescent field in a region adjacent to a touch surface of the touch panel;   generating a reflected pulse from an object located within the region adjacent to the touch surface of the touch panel; and   triangulating a position of the object on the touch surface of the touch panel at least in part from the reflected pulse.   
     
     
         2 . The method of  claim 1 , wherein the step of triangulating further comprises:
 receiving the reflected pulse by a first receiver and a second receiver that are separated from one another by a distance; and   calculating the position of the object based at least in part on a first elapsed time between transmission and reception at the first receiver, a second elapsed time between transmission and reception at the second receiver, and the distance.   
     
     
         3 . The method of  claim 1 , wherein the reflected pulse further comprises a first reflected pulse, and wherein the step of triangulating further comprises:
 generating a second reflected pulse from a reflector included in the touch panel;   receiving the first and second reflected pulses by a receiver; and   calculating the position of the objected from the first and second reflected pulses.   
     
     
         4 . The method of  claim 3 , wherein the reflector is located along the periphery of the touch panel. 
     
     
         5 . The method of  claim 1 , wherein the pulse further comprises a first pulse, and wherein the reflected pulse further comprises a first reflected pulse, and wherein the first pulse is transmitted by a first transceiver, and wherein the method further comprises:
 transmitting a second pulse of terahertz radiation through a touch panel by a second transceiver; and   generating a second reflected pulse from an object located within the region adjacent to the touch surface of the touch panel.   
     
     
         6 . The method of  claim 5 , wherein the step of triangulating further comprises triangulating the location of the object on the touch surface of the touch panel from the first and second reflected pulses. 
     
     
         7 . An apparatus comprising:
 a touch panel formed of a dielectric material that is configured to carry terahertz radiation and having a touch surface; and   a touch controller that is optically coupled to touch panel, wherein the touch controller is configured to transmit a pulse of terahertz radiation through the touch panel so as to generate a evanescent field in a region adjacent to the touch surface, and wherein the touch controller is configured to receive a reflected pulse that is generated by an object located within the region, and wherein the touch controller is configured to triangulate a position of the object on the touch surface at least in part from the reflected pulse.   
     
     
         8 . The apparatus of  claim 7 , wherein the touch controller further comprises:
 a signaling circuit that is configured to generate and receive terahertz radiation; and   a control circuit that is coupled to the signal circuit.   
     
     
         9 . The apparatus of  claim 8 , wherein the signaling circuit further comprises:
 a transceiver;   a local oscillator that is coupled to the transceiver; and   a receiver circuitry that is coupled to the transceiver.   
     
     
         10 . The apparatus of  claim 9 , wherein the receiver circuitry further comprises an analog baseband circuit that averages the combined signal for a plurality of sampling periods within a digitization window to generate a plurality of averaged signals and that converts the plurality of averaged signals to a digital signal. 
     
     
         11 . The apparatus of  claim 10 , wherein the analog baseband circuit further comprises:
 a clock circuit;   a low noise amplifier (LNA) that is coupled to the summing circuit;   an averager that is coupled to the LNA and the clock circuit;   an analog-to-digital converter (ADC) that is coupled to the LNA and the clock circuit; and   an output circuit that is coupled to the ADC.   
     
     
         12 . The apparatus of  claim 11 , wherein the transmitter further comprises:
 a transmitter that is coupled to the local oscillator; and   a plurality of receivers that are spaced apart from one another and that are each coupled to the receiver circuitry.   
     
     
         13 . The apparatus of  claim 12 , wherein the touch panel further comprises a reflector. 
     
     
         14 . A method comprising:
 transmitting a pulse of terahertz radiation through a touch panel formed of a dielectric material such that the pulse generates a evanescent field in a region adjacent to a touch surface of the touch panel;   generating a plurality of reflected pulses, wherein a first reflected pulse is generated by a object located within the region adjacent to the touch surface of the touch panel; and   triangulating a position of the object on the touch surface of the touch panel at least in part from the plurality of reflected pulses.   
     
     
         15 . The method of  claim 14 , wherein the object further comprises a first object, and wherein the position further comprises a first position, and wherein a second reflected pulse of the plurality of reflected pulses is generated by a object located within the region adjacent to the touch surface of the touch panel and at a second location. 
     
     
         16 . The method of  claim 15 , wherein the step of triangulating further comprises:
 receiving the plurality of reflected pulses by a first receiver and a second receiver that are separated from one another by a distance; and   calculating the position of the object based at least in part on the plurality of reflected pulses.   
     
     
         17 . The method of  claim 16 , wherein a third reflected pulse of the plurality of reflected pulses is generated by a reflector. 
     
     
         18 . The method of  claim 17 , wherein the reflector is located along the periphery of the touch panel.