INFRARED TOUCH SCREEN DEVICE AND MULTIPOINT LOCATING METHOD THEREOF

• US 20120218230A1
• Filed: 11/02/2010
• Published: 08/30/2012
• Est. Priority Date: 11/05/2009
• Status: Abandoned Application

• Current Assignee: Shanghai Jingjing Electronic Technology Company Limited
• Original Assignee: Shanghai Jingjing Electronic Technology Company Limited
• Inventors: Zhao, Lei, Zhang, Yuming
• Application Number:
  US13/508,125
• Publication Number:
  US 20120218230A1
• Time in Patent Office: Days
• US Class Current: 345/175
• CPC Class Codes: G06F 2203/04104 Multi-touch detection in digitiser, i.e. details about the simultaneous detection of a plurality of touching locations, e.g. multiple fingers or pen and finger
• CPC Class Codes: G06F 3/0421 by interrupting or reflecting a light beam, e.g. optical touch-screen

Abstract

An infrared touch screen device and a multi-touch locating method thereof are provided. On the touch screen, large angle infrared emitting elements and infrared receiving element are used to realize the axis scanning of multi-angle by an optimized sampling and processing circuit. After the data processing of removing ambient light, normalization and so on for original data of the axis scanning, the logic axis touch information is generated, and a luminance map of the current frame is generated according to the information. Multiple valid touch regions are recognized by contrast with a theoretical touch luminance map. Then a tracing algorithm of image is used, and a multi-touch event is outputted finally. The touch device is simple, reliable and accurate and has wide range application.

Claims

1. An infrared touch screen device, comprising:

infrared transmission units having greater transmission angle ranges and infrared reception units having greater reception angle ranges, adapted for performing axis scanning along various angles to obtain original axis scanning data, wherein the original axis scanning data are processed by removing environmental lights and normalization to generate logical touch data which is followed by processing the logical touch data to form a practical brightness map of current frame and comparing the practical brightness map with a theoretical brightness map to determine touch regions successively.

2. The infrared touch screen device according to claim 1, further comprising multiple sets of analog signal processing devices.

3. The infrared touch screen device according to claim 1, further comprising multiple analog digital converter devices.

4. The infrared touch screen device according to claim 1, wherein the infrared reception units are continually supplied with electricity, or supplied with electricity in groups.

5. A method for positioning multiple touch points on an infrared touch screen, comprising:

predetermining scanning axes and scanning angles corresponding to the scanning axes, and initializing hardware of an infrared touch screen device;

creating an image which has a same resolution in magnitude as that of a touch screen, and initializing brightness of each pixel point as 0;

successively performing axis scannings in different angles in a scanning period, obtaining logical touch data groups of the axes by data processing to the axis scanning data, such as substraction of environmental lights and normalization, wherein each logical touch data group includes a starting positions of an axis scanning region of an touch point and a width of axis scanning region of the touch point, and the logical touch data group has following formats;

a starting position 1, a width 1, a starting position 2, a width 2 . . . , a starting position N, a width N, N is a natural number;

or a starting position 1, an ending position 1, a starting position 2, an ending position 2 . . . , a starting position N, an ending position N;

or other similar formats indicating these logical information, N is a natural number;

finding parallelogram axis scanning regions according to logical touch data groups (including the axis angles, starting positions, and widths) obtained in the step 3 in the image created in the step 2, and forming a practical brightness map after successively processing all logical touch data groups, wherein a logical touch information group corresponds to a parallelogram axis scanning region, and at each time after finding a parallelogram axis scanning region, brightness of pixel points in the parallelogram axis scanning region is increased by 1;

calculating theoretical brightness of each pixel when is in touched state to create a theoretical brightness map; and

comparing the practical brightness map with theoretical brightness map to determine touch regions, wherein the region whose theoretical brightness is equal to it'"'"'s practical brightness is a touch region where the touch event happens.

6. The method according to claim 5, further comprising:

obtaining different blob information of the touch regions at different frames, and determining types of the touch events by combination a tracking algorithm with analyzing the blob information.

7. The method according to claim 5, wherein the infrared transmission units and infrared reception units are arranged along a length direction or a width direction of the touch screen in the infrared touch screen device.