Liquid crystal display

• US 20100156825A1
• Filed: 09/03/2009
• Published: 06/24/2010
• Est. Priority Date: 12/18/2008
• Status: Active Grant

• Current Assignee: LG Display Co., Ltd.
• Original Assignee: LG Display Co., Ltd.
• Inventors: Bae, Sanghyuck, Sohn, Minho, Choi, Jongseong, Jang, Hyunguk, Yu, Byungchum, Lee, Sangrae, Han, Jaejung
• Granted Patent: US 8,269,740 B2
• Time in Patent Office: Days
• US Class Current: 345/173
• CPC Class Codes: G06F 2203/04808 Several contacts: gestures triggering a specific function, e.g. scrolling, zooming, right-click, when the user establishes several contacts with the surface simultaneously; e.g. using several fingers or a combination of fingers and pen
• 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
• CPC Class Codes: G06F 3/0488 using a touch-screen or digitiser, e.g. input of commands through traced gestures

Abstract

A multi-touch sensing method and apparatus are described. The multi-touch sensing method includes: storing, in a memory, coordinate values of a first dead zone and coordinate values of a second dead zone existing between first and second pair of image sensors, respectively; calculating coordinate values of touch points from images obtained by the first and second pairs of image sensors; comparing the coordinate values of the touch point and the coordinate values of the dead zones to identify the location of the dead zone to which the touch point belongs; selecting the coordinate values calculated in the third step if the coordinate values of the touch point belong to the first dead zone; and selecting the coordinate values calculated in the second step if the coordinate values of the touch point belong to the second dead zone.

Claims

1. A multi-touch sensing method, comprising:

(A) storing, in a memory, coordinate values of a first dead zone existing between a first pair of image sensors and coordinate values of a second dead zone existing between a second pair of image sensors;

(B) calculating coordinate values of a touch point from images obtained by the first pair of image sensors;

(C) calculating the coordinate values of the touch point from images obtained by the second pair of image sensors;

(D) comparing the coordinate values of the touch point and the coordinate values of the dead zones to identify a location of the dead zone to which the touch point belongs;

(E) selecting the coordinate values calculated in the third step if the coordinate values of the touch point belong to the first dead zone; and

(F) selecting the coordinate values calculated in step B if the coordinate values of the touch point belong to the second dead zone.

2. The multi-touch sensing method of claim 1, wherein the first pair of image sensors includes first and second image sensors, and the second pair of image sensors includes the first image sensor and a third image sensor.

3. The multi-touch sensing method of claim 1, wherein, as a result of calculations of the A and B steps, steps C to F are processed if there exists only one coordinate value calculated from the images of the first and second pairs of image sensors.

4. The multi-touch sensing method of claim 2, further comprising:

deleting coordinate values of a virtual image among the coordinate values, if it is judged that there exists a plurality of coordinate values which are calculated from the images of the first and second pairs of image sensors as a result of calculation of the first and second steps, wherein the C to F steps are processed after the virtual image is eliminated.

5. The multi-touch sensing method of claim 4, wherein the deleting of coordinate values of a virtual image comprises:

calculating angle values of the touch points from an image obtained from the third image sensor and storing the angle value in the memory;

calculating angle values between the coordinate values calculated in the B step and the third image sensor; and

comparing the angle values of the touch points stored in the memory with the angle values between the coordinate values calculated in the B step and the third image sensor and selecting the touch points having a smaller difference therebetween.

6. A multi-touch sensing apparatus, comprising:

first and second pairs of image sensors installed in the vicinity of the corners of a touch surface;

a memory for storing coordinate values of a first dead zone existing between the first pair of image sensors and coordinate values of a second dead zone existing between the second pair of image sensors; and

a multi-touch processor which calculates coordinate values of a touch point from images obtained by the first pair of image sensors and coordinate values of the touch point from images obtained by the second pair of image sensors, compares the coordinate values of the touch point and the coordinate values of the dead zones to identify a location of the dead zone to which the touch point belongs as a result of comparison, selects the coordinate values calculated from the images obtained by the second pair of image sensors if the coordinate values of the touch point belong to the first dead zone, and selects the coordinate values calculated from the images obtained by the first pair of image sensors if the coordinate values of the touch point belong to the second dead zone.

7. The multi-touch sensing apparatus of claim 6, wherein the first pair of image sensors includes first and second image sensors, and the second pair of image sensors includes the first image sensor and a third image sensor.

8. The multi-touch sensing apparatus of claim 6, wherein, as a result of calculating the coordinate values of the touch point from images obtained by the first pair of image sensors and the coordinate values of the touch point from images obtained by the second pair of image sensors, if there exists only one coordinate value, the multi-touch processor compares the coordinate values of the touch point and the coordinate values of the dead zones to identify the location of the dead zone to which the touch point belongs as a result of comparison, selects the coordinate values calculated from the images obtained by the second pair of image sensors if the coordinate values of the touch point belong to the first dead zone, and selects the coordinate values calculated from the images obtained by the first pair of image sensors if the coordinate values of the touch point belong to the second dead zone.

9. The multi-touch sensing apparatus of claim 7, wherein, as a result of calculating the coordinate values of the touch point from images obtained by the first pair of image sensors and the coordinate values of the touch point from images obtained by the second pair of image sensors, the multi-touch processor eliminates coordinate values of a virtual image among the coordinate values if there exists a plurality of coordinate values calculated from the images of the first and second pairs of image sensors.

10. The multi-touch sensing apparatus of claim 9, wherein the multi-touch processor:

calculates angle values of the touch points from an image obtained from the third image sensor and storing the angle values in the memory;

calculates angle values between the coordinate values of the touch point from images obtained by the first pair of image sensors and the third image sensor; and

compares the angle values of the touch points stored in the memory with the angle values between the coordinate values of the touch point from images obtained by the first pair of image sensors and the third image sensor, and selects the touch points having a smaller difference therebetween.