Multi Position Detecting Method and Area Detecting Method in Infrared Rays Type Touch Screen

• US 20080304084A1
• Filed: 09/27/2007
• Published: 12/11/2008
• Est. Priority Date: 09/29/2006
• Status: Active Grant

• Current Assignee: Kil-Sun Kim, Nexio Company Limited
• Original Assignee: Kil-Sun Kim, Nexio Company Limited
• Inventors: Kim, Yong-Chul, Kim, Kil-Sun
• Granted Patent: US 7,688,455 B2
• Time in Patent Office: Days
• US Class Current: 356/614
• CPC Class Codes: G06F 3/0421 by interrupting or reflecting a light beam, e.g. optical touch-screen

Abstract

A method for detecting the coordinates of multiple touching objects on an infrared touch screen without errors and a method for detecting the area of the touched spot are provided. The coordinate detection method includes measuring and storing the maximum received level of a pair of infrared emitting and receiving elements, emission and reception of which is not impeded by any object, and initializing an index variable for identification of multiple touched spots, determining that the screen has been touched when a received level of a pair of infrared emitting and receiving elements, emission and reception of which is impeded by an object, is less than the maximum level, measuring the minimum level to detect center coordinates of the object, and reading an index variable for the center coordinates and determining that the center coordinates are new and setting an index variable for the center coordinates if no index variable is read for the center coordinates and storing the center coordinates and the index variable for the center coordinates. The area detection method also includes measuring received levels of three pairs of infrared emitting and receiving elements corresponding to the center and two ends of the object and measuring and storing X and Y-axis diameters of a spot touched by the object based on the measured levels, and measuring the area of the touched spot based on the diameters under the assumption that the spot is an oval.

Claims

1. A method for detecting the coordinates of multiple positions on an infrared touch screen of a touch panel including a plurality of X-axis infrared emitting and receiving elements and a plurality of Y-axis infrared emitting and receiving elements, the method comprising:

measuring and storing a maximum received optical level of a pair of infrared emitting and receiving elements, infrared emission and reception of which is not impeded by any object, and initializing an index variable used to identify multiple touched spots

determining that the touch screen has been touched when a received optical level of a pair of infrared emitting and receiving elements, infrared emission and reception of which is impeded by an object, is less than the maximum received optical level

measuring a minimum received optical level of the pair of infrared emitting and receiving elements to detect center coordinates of the object; and

reading an index variable for the center coordinates and determining that the center coordinates are new and setting an index variable for the center coordinates if no index variable is read for the center coordinates and storing the center coordinates and the index variable for the center coordinates.

2. The method according to claim 1, further comprising:

comparing each received optical level measured using the infrared emitting and receiving elements with the maximum received optical level and deleting all stored center coordinates and corresponding index variables if it is determined from the comparison that the touch screen has not been touched.

3. The method according to claim 1, further comprising:

determining that the center coordinates are continuous, if a spot corresponding to the stored center coordinates with the index variable set for the center coordinates has been moved at a movement speed less than a preset movement speed limit, and storing center coordinates of the spot after the movement, replacing the stored center coordinates, for the index variable.

4. The method according to claim 3, further comprising transmitting information, including an indicator of whether or not a spot on the touch panel has been touched or whether or not a touched spot has been released, indicators of whether or not each spot has been kept touched or has been released, index variables allocated respectively to touched spots, respective X and Y coordinates of touched spots, and the number of one or more measured objects, to an information device.

5. A method for detecting the area of a touched spot on an infrared touch screen of a touch panel including a plurality of X-axis infrared emitting and receiving elements and a plurality of Y-axis infrared emitting and receiving elements, the method comprising:

measuring and storing a maximum received optical level of a pair of infrared emitting and receiving elements, infrared emission and reception of which is not impeded by any object, and initializing an index variable used to identify multiple touched spots;

determining that the touch screen has been touched when a received optical level of a pair of infrared emitting and receiving elements, infrared emission and reception of which is impeded by an object, is less than the maximum received optical level

measuring a minimum received optical level of the pair of infrared emitting and receiving elements to detect center coordinates of the object; and

measuring a received optical level of a pair of infrared emitting and receiving elements placed on a center axis of the object, a received optical level of a pair of infrared emitting and receiving elements corresponding to a left end of the object, and a received optical level of a pair of infrared emitting and receiving elements corresponding to a right end of the object and measuring and storing an X-axis diameter and a Y-axis diameter of a spot touched by the object based on the measured levels and

measuring an area of the touched spot based on the measured X and Y-axis diameters under assumption that the spot is an oval.

6. The method according to claim 5, further comprising transmitting information, including an indicator of whether or not a spot on the touch panel has been touched or whether or not a touched spot has been released, indicators of whether or not each spot has been kept touched or has been released, index variables allocated respectively to touched spots, respective X and Y coordinates of touched spots, measured X and Y diameters of touched spots, and the number of one or more measured objects, to an information device.