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

• US 8,139,045 B2
• Filed: 05/10/2007
• Issued: 03/20/2012
• Est. Priority Date: 12/15/2006
• Status: Active Grant

• Current Assignee: LG Display Co., Ltd.
• Original Assignee: LG Display Co., Ltd.
• Inventors: Jang, Hyung Uk, Bae, Sang Hyuck, Shim, Yeon Shim
• Primary Examiner(s): Hjerpe, Richard
• Assistant Examiner(s): Okebato, Sahlu
• Application Number:
  US11/798,124
• Publication Number:
  US 20080143690A1
• Time in Patent Office: 1,776 Days
• Field of Search: 345/173, 345/175, 178 1801- 1803, 178/18.09, 178/18.11, 178/19.05
• 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 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, the processor including;

a memory that stores a plurality of compensation angles in a range of 0 to 90 degrees corresponding to each of the plurality of cameras; and

an adder connected to the output terminal of the look-up-table, which adds the compensation angle from the memory to a measurement angle inclusive of the distortion amount caused by lens aberration,

wherein the processor is operated in synchronization with a timing controller by a timing signal,

wherein the compensation angles ‘

θ

error’

are defined by steps comprising;

calculating an accurate measurement angle θ

using θ

=arc tan(A), wherein A is an actual touch area;

calculating a mis-recognized measurement angle θ

′

using the following equations;

A′

=c×

(A×

sin(90−

θ

)

θ

′

=arc tan(A′

)

calculating the compensation angle using θ

error=θ

−

θ

′

wherein ‘

c’

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

c≦

1.

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. 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 0 to 90 degrees corresponding to each of the plurality of cameras, the method comprising:

operating in synchronization between a processor and a timing controller by a timing signal;

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, by adding at least one of the compensation angles from a memory to a measurement angle inclusive of the distortion amount caused by lens aberration,

wherein the compensation angles ‘

θ

error’

are defined by steps comprising;

calculating an accurate measurement angle θ

using θ

=arc tan(A), wherein A is an actual touch area;

calculating a mis-recognized measurement angle θ

′

using the following equations;

A′

=c×

(A×

sin(90−

θ

)

θ

′

=arc tan(A′

)

calculating the compensation angle using θ

error=θ

−

θ

′

wherein ‘

c’

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

c≦

1.

5. The method of claim 4, wherein the compensation angles are symmetric with respect to 45 degrees.

6. The method of claim 4, wherein each of the compensation angles characterizes a distortion at the corresponding angle with respect to an axis of the corresponding camera.

7. 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:

operating in synchronization between a processor and a timing controller by a timing signal;

capturing a first captured image of a touched first reference on a surface of the display panel using the first capture device wherein the first reference has first and second reference angles relative to the first and second 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;

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, and

adding at least one of the first and second compensation angles from a memory to a measurement angle inclusive of the distortion amount caused by lens aberration,

wherein the compensation angles ‘

θ

error’

are defined by steps comprising;

calculating an accurate measurement angle θ

using θ

=arc tan(A), wherein A is an actual touch area;

calculating a mis-recognized measurement angle θ

′

using the following equations;

A′

=c×

(A×

sin(90−

θ

)

θ

′

=arc tan(A′

)

calculating the compensation angle using θ

error=θ

−

θ

′

wherein ‘

c’

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

c≦

1.

8. The method of claim 7, further comprising fitting the first and second compensation angles to a substantially polynomial curve.

9. The method of claim 8, further comprising storing a plurality of coefficients corresponding to the substantially polynomial curve in a rewritable storage part.

10. 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 0 to 90 degrees corresponding to each of the plurality of cameras, the method comprising:

operating in synchronization between a processor and a timing controller by a timing signal;

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;

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, and

adding at least one of the compensation angle from a memory to a measurement angle inclusive of the distortion amount caused by lens aberration,

wherein the compensation angles ‘

θ

error’

are defined by steps comprising;

calculating an accurate measurement angle θ

using θ

=arc tan(A), wherein A is an actual touch area;

calculating a mis-recognized measurement angle θ

′

using the following equations;

A′

=c×

(A×

sin(90−

θ

)

θ

′

=arc tan(A′

)

calculating the compensation angle using θ

error=θ

−

θ

′

wherein ‘

c’

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

c≦

1.

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

operating in synchronization between a processor and a timing controller by a timing signal;

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, and

adding the compensation angle from a memory to a measurement angle inclusive of the distortion amount caused by lens aberration,

wherein the compensation angles ‘

θ

error’

are defined by steps comprising;

calculating an accurate measurement angle θ

using θ

=arc tan(A), wherein A is an actual touch area;

calculating a mis-recognized measurement angle θ

′

using the following equations;

A′

=c×

(A×

sin(90−

θ

)

θ

′

=arc tan(A′

)

calculating the compensation angle using θ

error=θ

−

θ

′

wherein ‘

c’

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

c≦

1.