Touch Detection Sensing Apparatus

• US 20110074738A1
• Filed: 05/19/2009
• Published: 03/31/2011
• Est. Priority Date: 06/18/2008
• Status: Abandoned Application

• Current Assignee: Sansheng Intellectual Education Technology Co., Ltd.
• Original Assignee: Sansheng Intellectual Education Technology Co., Ltd.
• Inventors: Liu, Xinbin, Liu, Jianjun, Ye, Xinlin
• Application Number:
  US12/922,079
• Publication Number:
  US 20110074738A1
• Time in Patent Office: Days
• US Class Current: 345/175
• CPC Class Codes: G06F 3/0428 by sensing at the edges of the touch surface the interruption of optical paths, e.g. an illumination plane, parallel to the touch surface which may be virtual sensing beam interruptions in a planar beam grid of an optical touch-screen G06F3/0421

Abstract

A touch detection sensing apparatus is disclosed, which comprises: at least one image capturing device, at least one reflection mirror and an image processing circuit. The at least one image capturing device is used to capture an image of a touch object in a detected screen and an image of a virtual image of the touch object in the at least one reflection mirror. The image processing circuit can calculate a position of the touch object based on the image of the touch object and the image of the virtual image of the touch object in a reflection mirror captured by an image capturing device.

Claims

1. A touch detection sensing apparatus for detecting a position of a touch object on a detected screen, comprising:

at least one reflection mirror, wherein a reflection surface of each reflection mirror is towards the detected screen, such that the detected screen can be imaged as a virtual image in the at least one reflection mirror;

at least one image capturing device for capturing an image of the touch object on the detected screen and capturing an image of the virtual image of the touch object in the reflection mirror, wherein an overlapping of respective field of view of the at least one image capturing device covers the whole detected screen; and

an image processing circuit that receives image data captured by the at least one image capturing device and calculates the position of the touch object on the detected screen based on the image of the touch object and the image of the virtual image of the touch object in a reflection mirror captured by the image capturing device.

2. The touch detection sensing apparatus of claim 1, which only comprises one image capturing device and one reflection mirror, the field of view of the image capturing device covers the whole detected screen and the whole image of the detected screen in the reflection mirror.

3. The touch detection sensing apparatus of claim 2, wherein the detected screen is of a rectangle shape, and wherein the reflection mirror is of a strip shape which extends along one edge of the rectangle longitudinally, and a longitudinal length of the reflection mirror at least equals to that of the one edge of the rectangle.

4. The touch detection sensing apparatus of claim 3, wherein the image capturing device is disposed at a corner of the rectangle, and the reflection mirror is located on an edge opposite to one of the two edges forming the corner.

5. The touch detection sensing apparatus of claim 1, which comprises two image capturing devices and one reflection mirror, wherein the field of view or effective field of view of each image capturing device only covers a portion of the detected screen, and the overlapping of the fields of view or effective fields of view of the two image capturing devices covers the whole detected screen,

when the touch object appears in the common field of view or effective field of view of the two image capturing devices, the image processing circuit calculates the position of the touch object on the detected screen based on the image of the touch object captured by the two image capturing devices;

when the touch object appears in the field of view or effective field of view covered only by one image capturing device, the image processing circuit calculates the position of the touch object in the detected screen based on the image of the touch object and the image of the virtual image of the touch object in the reflection mirror captured by the one image capturing device.

6. The touch detection sensing apparatus of claim 5, wherein the detected screen is of a rectangle shape, and wherein the reflection mirror is of a strip shape which extends along one edge of the rectangle longitudinally, and a longitudinal length of the reflection mirror equals to that of the one edge of the rectangle.

7. The touch detection sensing apparatus of claim 6, wherein the two image capturing devices are disposed at two corners of the rectangle respectively, and the reflection mirror is installed on an edge which is not the edges forming the corner where the image capturing device is disposed.

8. The touch detection sensing apparatus of claim 6, wherein the edge where the reflection mirror is located is a long edge of the rectangle.

9. The touch detection sensing apparatus of claim 1, which comprises two image capturing devices and two reflection mirrors, wherein the field of view of each image capturing device does not cover the whole detected screen, the overlapping of the fields of view of the two image capturing devices covers the whole detected screen.

10. The touch detection sensing apparatus of claim 9, wherein the detected screen is of a rectangle shape, and wherein both reflection mirrors are of a strip shape and are disposed on two opposite edges of the rectangle respectively and extend along the two edges, a length of each reflection mirror at least equals to a length of the corresponding edge.

11. The touch detection sensing apparatus of claim 10, wherein when the touch object appears in the common field of view of the two image capturing devices, the image processing circuit calculates the position of the touch object on the detected screen based on the image of the touch object captured by the two image capturing devices;

when the touch object appears in the field of view covered only by one image capturing device, the image processing circuit calculates the position of the touch object on the detected screen based on the image of the touch object and the image of the virtual image of the touch object in a reflection mirror captured by the one image capturing device.

12. The touch detection sensing apparatus of claim 11, wherein the two image capturing devices are disposed at two adjacent corners of the rectangle respectively, and wherein the two reflection mirrors are installed on two opposite edges that are not common for the two corners where the image capturing devices are disposed.

13. The touch detection sensing apparatus of claim 12, wherein the reflection mirrors are disposed on short edges of the rectangle.

14. The touch detection sensing apparatus of claim 11, wherein the two reflection mirrors are disposed on the long edges of the rectangle, and wherein the two image capturing devices are disposed on two edges adjacent to the edges of the rectangle where the two reflection mirrors are installed respectively.

15. The touch detection sensing apparatus of claim 1, wherein when the image processing circuit calculates the position of the touch object on the detected screen based on the image of the touch object and the image of the virtual image of the touch object in a reflection mirror captured by an image capturing device, the image processing circuit uses the following formulas:

y₁=xtgα

2y₂+y₁=xtgβ

y₁+y₂=H+y₀

wherein an origin of a coordinate system used by the above formulas is a vertex of field angle of the image capturing device, two coordinate axes are parallel to two adjacent edges of the rectangular detected screen respectively;

angle α

is an angle between a line from the touch object to the vertex of the field angle of the image capturing device and the coordinate axis in parallel with the reflection mirror;

angle β

is an angle between a line from the virtual image of the touch object in the reflection mirror to the vertex of the field angle of the image capturing device and the coordinate axis in parallel with the reflection mirror;

y₀ is a distance from an edge of the detected screen opposite to the reflection mirror to the coordinate axis in parallel with the reflection mirror;

y₁ is a distance from the touch object to the coordinate axis in parallel with the reflection mirror;

y₂ is a distance from the touch object to the reflection mirror.

16. The touch detection sensing apparatus of claim 1, wherein the image capturing device is a camera.

17. The touch detection sensing apparatus of claim 16, wherein a photoelectric sensor chip in the camera is a line array photosensitive chip.

18. The touch detection sensing apparatus of claim 6, wherein the two image capturing devices are disposed on different planes in parallel with the detected screen respectively.

19. The touch detection sensing apparatus of claim 1, wherein at least one infrared light source is disposed on an edge of the detected screen, so as to emit infrared light toward the detected area.

20. The touch detection sensing apparatus of claim 19, wherein four infrared light sources are disposed so as to illuminate the detected screen from four directions.

21. The touch detection sensing apparatus of claim 19, wherein each of the infrared light sources comprises an infrared light-emitting tube.

22. The touch detection sensing apparatus of claim 21, wherein a concave lens is disposed in front of each of the infrared light sources.

23. The touch detection sensing apparatus of claim 19, wherein each of the infrared light sources comprises a plurality of infrared light-emitting tubes arranged in a sector.

24. The touch detection sensing apparatus of claim 19, wherein an infrared color filter is disposed on an optical path before each of the image capturing devices.

25. The touch detection sensing apparatus of claim 1, wherein the detected screen is a touch area of a touch screen.

26. The touch detection sensing apparatus of claim 11, wherein the two image capturing devices are disposed on different planes in parallel with the detected screen respectively.