Display device having multi-touch recognizing function and driving method thereof

• US 20080143690A1
• Filed: 05/10/2007
• Published: 06/19/2008
• Est. Priority Date: 12/15/2006
• Status: Active Grant

• Current Assignee: LG Display Co., Ltd.
• Original Assignee: LG Philips LCD Company Limited (LG Display Co., Ltd.)
• Inventors: Shim, Yeon Shim, Bae, Sang Hyuck, Jang, Hyung Uk
• Granted Patent: US 8,139,045 B2
• 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 display device having a multi-touch recognition function includes an integration module having a plurality of cameras integrated at an edge of a display panel; a look-up-table of a plurality of compensation angles in an range of about 0 to about 90 degrees corresponding to each of the plurality of cameras; and processor that detects a touch area using at least first and second images captured by the plurality of cameras, respectively, and compensates the detected touch area with one of the plurality of compensation angles.

Claims

1. A display device having a multi-touch recognition function, comprising:

an integration module having a plurality of cameras integrated at an edge of a display panel;

a look-up-table of a plurality of compensation angles in an range of about 0 to about 90 degrees corresponding to each of the plurality of cameras; and

a processor that detects a touch area using at least first and second images captured by the plurality of cameras, respectively, and compensates the detected touch area with one of the plurality of compensation angles.

2. The display device of claim 1, wherein the compensation angles are symmetric with respect to 45 degrees.

3. The display device of claim 1, wherein each of the compensation angles characterizes a distortion at the corresponding angle with respect to an axis of the corresponding camera.

4. The display device of claim 1, further comprising an adder for adding to detected touch area to the compensation angle.

5. A method of recognizing a multi-touch on a display device including an integration module having a plurality of cameras assembled with a display panel and a storage part for storing a plurality of compensation angles in an range of about 0 to about 90 degrees corresponding to each of the plurality of cameras, the method comprising:

capturing first and second images using the cameras;

detecting a touch area using the first and second images; and

compensating the detected touch area with one of the plurality of the compensation angles.

6. The method of claim 5, wherein the compensation angles are symmetric with respect to 45 degrees.

7. The method of claim 5, wherein each of the compensation angles characterizes a distortion at the corresponding angle with respect to an axis of the corresponding camera.

8. The method of claim 5, wherein the compensating includes adding the compensation angle to the detected touch area.

9. The method of claim 5, wherein the compensation angles ‘

θ

error’

are defined as below.

A=tan θ

A′

=c×

(A×

sin(90−

θ

)/sin(90−

0.5θ

))×

sin(90−

0.5θ

)

θ

′

=arc tan(A′

)

θ

error=θ

−

θ

′

Herein, ‘

A’

is an actual touch area being in an accurate measurement angle ‘

θ

’

, ‘

A′

’

is a mis-recognized touch area in the measurement angle ‘

θ

′

’

that a lens distortion is reflected, and ‘

c’

is a constant value, i.e., lens coefficient, representing a unique characteristic of lens having a value of 0<

c≦

1.

10. A method of recognizing a multi-touch on a display panel of display device including first and second capture devices assembled with the display panel, comprising:

selecting a first reference on a surface of the display panel, the first reference having first and second reference angles relative to the first and second capture devices;

touching the selected first reference;

capturing a first captured image of the touched first reference using the first capture device;

capturing a second captured image of the touched first reference using the second capture device;

detecting first and second contact angles of the touched first reference relative to the first and second capture devices, respectively, by a triangulation operation on a basis of the first and second captured images; and

computing first and second compensation angles corresponding to the first and second capture devices, respectively, in accordance with corresponding differences between the first and second reference angles and the first and second contact angles, respectively.

11. The method of claim 10, further comprising fitting the first and second compensation angles to a substantially polynomial curve.

12. The method of claim 11, further comprising storing a plurality of coefficients corresponding to the substantially polynomial curve in a rewritable storage part.

13. A method of recognizing a multi-touch on a display device including an integration module having a plurality of cameras assembled with a display panel and a storage part for storing a plurality of compensation angles in an range of about 0 to about 90 degrees corresponding to each of the plurality of cameras, the method comprising:

substantially simultaneously capturing first, second, third and fourth images using first, second, third and fourth cameras from the plurality of cameras;

detecting one or more touch area using the first and second images;

detecting the one or more touch area using the third and fourth images;

compensating the detected one or more touch area with compensation angles corresponding to the first, second, third and fourth cameras, respectively; and

verifying the one or more touch area detected using the first and second images with the one or more touch area detected using the third and fourth cameras.

14. A method of recognizing a multi-touch on a display panel of display device including a capture device assembled with the display panel, comprising:

selecting a reference on a surface of the display panel, the reference having a reference angle relative to the capture devices;

touching the selected reference;

capturing an image of the touched reference using the capture device;

calculating a touched angle of the touched reference using the captured image;

computing a compensation angle according to a difference between the touched angle and the reference angle.