LIQUID CRYSTAL DISPLAY TO WHICH INFRARED RAYS SOURCE IS APPLIED AND MULTI-TOUCH SYSTEM USING THE SAME

• US 20090167656A1
• Filed: 12/23/2008
• Published: 07/02/2009
• Est. Priority Date: 12/31/2007
• Status: Active Grant

• Current Assignee: LG Display Co., Ltd.
• Original Assignee: LG Display Co., Ltd.
• Inventors: Yu, Byung-Chun, Jang, Hyung-Uk, Lee, Sang-Rae, Lim, Dae-San, AHN, In-Ho, Bae, Sang-Hyuck, Choi, Jong-Seong
• Granted Patent: US 8,624,810 B2
• Time in Patent Office: Days
• US Class Current: 345/87
• CPC Class Codes: G02F 1/13338 Input devices, e.g. touch panels
• CPC Class Codes: G02F 1/1336 Illuminating devices
• 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

There are provided a liquid crystal display (LCD) to which infrared rays (IR) light sources are applied and a multi-touch system using the same. The LCD to which IR light sources are applied includes a back light in which a plurality of lamp light sources and a plurality of IR light sources are repeatedly arranged in column and row directions, a diffusion plate and a plurality of optical sheets arranged on the back light, and an LCD panel provided on the back light to display an image using light incident from the back light.

Claims

1. A liquid crystal display (LCD) to which infrared rays (IR) light sources are applied, comprising:

a back light in which a plurality of lamp light sources and a plurality of IR light sources are repeatedly arranged in column and row directions;

a diffusion plate and a plurality of optical sheets arranged on the back light; and

an LCD panel provided on the back light to display an image using light incident from the back light.

2. The LCD as claimed in claim 1, wherein the lamp light source is selected from a light emitting diode (LED), electroluminescence (EL), a cold cathode fluorescent lamp (CCFL), and an external electrode fluorescent lamp (EEFL).

3. The LCD as claimed in claim 2, wherein, when the CCFL or the EEFL is used as the lamp light source, the plurality of IR light sources are repeatedly arranged together with one CCFL or EEFL.

4. The LCD as claimed in claim 2, wherein, when the LED light source is used as the lamp light source, one LED and one IR light source are repeatedly and alternately arranged in column and row directions.

5. The LCD as claimed in claim 2, wherein the LED light sources are repeatedly arranged in column and row directions in units of three R, G, and B LEDs and one IR light source.

6. The LCD as claimed in claim 1, wherein a touch panel is provided on the LCD panel.

7. A multi-touch system to which an LCD is applied, comprising:

the LCD including a back light in which a plurality of lamp light sources and a plurality of IR light sources are repeatedly arranged in column and row directions, an LCD panel provided on the back light to display an image using light incident from the back light, and a touch panel attached onto the LCD panel; and

a plurality of cameras that are provided on the LCD at edges and in which IR light incident from the IR light sources provided in the LCD is reflected by a touch object and the reflected IR light is incident to create a touch sense image.

8. The multi-touch system as claimed in claim 7, wherein the lamp light source is selected from a light emitting diode (LED), electroluminescence (EL), a cold cathode fluorescent lamp (CCFL), and an external electrode fluorescent lamp (EEFL).

9. The multi-touch system as claimed in claim 8, wherein, wherein, when the CCFL or the EEFL is used as the lamp light source, the plurality of IR light sources are repeatedly arranged together with one CCFL or EEFL.

10. The multi-touch system as claimed in claim 8, wherein, when the LED light source is used as the lamp light source, one LED and one IR light source are repeatedly and alternately arranged in column and row directions.

11. The multi-touch system as claimed in claim 8, wherein the LED light sources are repeatedly arranged in column and row directions in units of three R, G, and B LEDs and one IR light source.

12. The multi-touch system as claimed in claim 7, wherein an IR light transmission filter is provided in the LCD panel.