Touch panel and method for controlling same

• US 5,179,369 A
• Filed: 12/12/1991
• Issued: 01/12/1993
• Est. Priority Date: 12/06/1989
• Status: Expired due to Term

• Current Assignee: Vishay Dale Electronics (Vishay Intertechnology Incorporated)
• Original Assignee: Dale Electronics, Inc.
• Inventors: Veik, Thomas L., Person, Herman R.
• Primary Examiner(s): Weldon, Ulysses
• Assistant Examiner(s): FATAHI YAR, MAHMOUD
• Application Number:
  US07/806,143
• Time in Patent Office: 397 Days
• Field of Search: 340/706, 340/712, 178/18, 178/19, 341/20, 341/31, 250/221
• US Class Current: 345/175
• CPC Class Codes: G06F 3/0421 by interrupting or reflecting a light beam, e.g. optical touch-screen

Abstract

The touch panel mof the present invention comprises a plurality of beam emitter-detector pairs disposed around the perimeter of a video display area. The emitters direct energy beams toward the detectors which are located directly opposite across the display area from the emitters. A programmed central processor is connected to the emitters and is programmed to serquentially scan the emitters for actuating the emitters one at a time to create a modulated energy beam which is intermittently turned on and off for predetermined periods of time at a predetermined frequency. The detectors sense the modulated energy beams and create an electrical signal which is fed through a comparator and then to the central processor so that the central processor can analyze and determine the location of any blockage which appears on the screen.

Claims

1. A touch panel adapted to be connected to a host computer comprising:

a display area having a defined perimeter;

a plurality of beam emitter-detector pairs disposed around at least a portion of said perimeter of said display area;

said emitter-detector pairs each comprising an emitter adapted to be actuated to direct an energy beam, and a detector positioned across said display area opposite from said emitter for receiving said energy beam in response thereto;

central processor means separate from said host computer connected to said emitter-detector pairs;

computer program means within said central processor means for causing said central processor means to control the actuation and deactuation of said emitter-detector pairs one at a time sequentially to create a plurality of energy signals each of which comprises an actuated portion and a deactuated portion;

said computer program means being adapted to cause said central processor means to create a modulation signal for causing said actuated portions of said energy signals to be modulated at a predetermined frequency, whereby said emitters will emit a modulated energy beam during the time that they receive said modulation signal;

said detectors each being adapted to sense said modulated energy beam and create a first electrical beam signal whenever said modulated beam passes unobstructed from each of said emitters to each of said detectors, said detectors each creating a second electrical beam signal different from said first beam signal whenever there is an obstruction of said modulated beam between said emitter and said detector during said predetermined period of time;

blockage detection means connected to said detectors, and said central processor means for sending a blockage signal to said central processor means in response to said blockage detection means sensing said second signal;

said computer program means causing said central processor means to generate an output signal indicative of the location of said obstruction on said display area in response to receiving said blockage signal from said blockage detector means.

2. A touch panel according to claim 1 wherein said predetermined frequency is between 10 kilohertz and 500 kilohertz.

3. A touch panel according to claim 1 wherein said predetermined frequency is between 60 and 90 kilohertz.

4. A touch panel according to claim 1 wherein said blockage detection means comprises a comparator means for determining whether or not said first electrical beam signal or said second electrical beam signal is present at any given moment of time.

5. A method for controlling a touch panel system adapted to be connected to a host computer and adapted to locate the position of an object adjacent to a display surface, said method comprising:

placing a plurality of beam emitter-detector pairs around at least a portion of said perimeter of said display area, said emitter-detector pairs each comprising an emitter adapted to be actuated to direct an energy beam and a detector positioned across said display area opposite from said emitter for receiving said energy beam;

connecting a microprocessor separate from said host computer to said emitter-detector pairs;

programming said microprocessor with a computer program capable of causing said microprocessor to scan said emitter-detector pairs and to send an energy signal to each of said emitters;

using said computer program to cause said microprocessor to modulate a portion of said energy signal at a predetermined frequency and to send said energy signal to said emitters one at a time for causing said emitters to direct a modulated energy beam having said predetermined frequency toward said detectors;

using said detectors to create a first detector signal in response to receiving said modulated energy beam and a second detector signal whenever said object blocks said modulated energy beam;

using a blockage sensing means connected to said detectors for sending a blockage signal to said microprocessor in response to receiving said second detector signal;

using said computer program to analyze said blockage signal to cause said microprocessor to generate an output signal indicative of the location of said object in said display area in response to receiving said blockage signal form said blockage detector means.