Liquid crystal display

• US 20090315840A1
• Filed: 12/29/2008
• Published: 12/24/2009
• Est. Priority Date: 06/24/2008
• Status: Active Grant

• Current Assignee: LG Display Co., Ltd.
• Original Assignee: LG Display Co., Ltd.
• Inventors: Park, Shinkwon, Lee, Minkyung, Park, Changkeun, Choo, Kyohyuck, Do, Miyoung, Lee, Deuksu, Moon, Suhwan, Kim, Ilho, Kim, Taehwan
• Granted Patent: US 8,355,006 B2
• Time in Patent Office: Days
• US Class Current: 345/173
• CPC Class Codes: G02F 1/13338 Input devices, e.g. touch panels
• CPC Class Codes: G02F 1/133528 Polarisers
• CPC Class Codes: G06F 3/0412 Digitisers structurally integrated in a display
• CPC Class Codes: G06F 3/042 by opto-electronic means

Abstract

A liquid crystal display is disclosed. The liquid crystal display includes a liquid crystal display panel including a pixel array and touch sensors, a transparent conductive layer on one substrate of the liquid crystal display panel transmitting display light, a polarizing plate on the transparent conductive layer, a driving voltage supply circuit, and a signal transmitting unit electrically connecting the transparent conductive layer to the driving voltage supply circuit. A portion of the transparent conductive layer is connected to a ground level voltage source. The driving voltage supply circuit generates a driving voltage required to perform light sensing operations of the touch sensors during a touch period based on changes in an amount of surface charge of the transparent conductive layer depending on whether or not the polarizing plate is touched.

Claims

1. A liquid crystal display comprising:

a liquid crystal display panel including a pixel array that displays an image and touch sensors that sense a touch position depending on an amount of receiving light;

a transparent conductive layer on one substrate of the liquid crystal display panel transmitting display light, a portion of the transparent conductive layer being connected to a ground level voltage source;

a polarizing plate on the transparent conductive layer;

a driving voltage supply circuit to generate a driving voltage required to perform light sensing operations of the touch sensors during a touch period based on changes in an amount of surface charge of the transparent conductive layer depending on whether or not the polarizing plate is touched; and

a signal transmitting unit to electrically connect the transparent conductive layer to the driving voltage supply circuit.

2. The liquid crystal display of claim 1, wherein when a user touches the polarizing plate with his or her finger, the polarizing plate serves as a dielectric to form an equivalent capacitor between the user'"'"'s finger and the transparent conductive layer,

wherein the amount of surface charge of the transparent conductive layer has a different value during touch and non-touch operations.

3. The liquid crystal display of claim 1, wherein the polarizing plate includes a conductive layer and a dielectric layer between the conductive layer and the one substrate of the liquid crystal display panel,

wherein when a user touches the polarizing plate with his or her finger, the dielectric layer serves as a dielectric to form an equivalent capacitor between the conductive layer and the transparent conductive layer,

wherein the amount of surface charge of the transparent conductive layer has a different value during touch and non-touch operations.

4. The liquid crystal display of claim 1, wherein the signal transmitting unit includes:

a touch output pad on another substrate of the liquid crystal display panel;

a conductive tape to electrically connect the transparent conductive layer to one surface of the touch output pad;

a printed circuit board on which the driving voltage supply circuit is mounted; and

a flexible wiring film to electrically connect another surface of the touch output pad to the printed circuit board.

5. The liquid crystal display of claim 1, wherein the signal transmitting unit includes:

a printed circuit board on which the driving voltage supply circuit is mounted; and

a flexible wiring film to electrically connect the transparent conductive layer to the printed circuit board.

6. A liquid crystal display comprising:

a liquid crystal display panel including a pixel array that displays an image and touch sensors that sense a touch position depending on an amount of receiving light;

a first transparent conductive layer on one substrate of the liquid crystal display panel transmitting display light, the transparent conductive layer being connected to a ground level voltage source;

a polarizing plate on the first transparent conductive layer;

a second transparent conductive layer that is formed on the polarizing plate to be exposed to the outside, the first and second transparent conductive layers being on opposite sides of the polarizing plate;

a driving voltage supply circuit to generate a driving voltage required to perform light sensing operations of the touch sensors during a touch period based on changes in an amount of surface charge of the second transparent conductive layer depending on whether or not the second transparent conductive layer is touched; and

a signal transmitting unit to electrically connect the second transparent conductive layer to the driving voltage supply circuit.

7. The liquid crystal display of claim 6, wherein when a user touches the second transparent conductive layer with his or her finger, the polarizing plate serves as a dielectric to form an equivalent capacitor between the first and second transparent conductive layers,

wherein the amount of surface charge of the second transparent conductive layer has a different value during touch and non-touch operations.

8. The liquid crystal display of claim 6, wherein the signal transmitting unit includes:

a touch output pad on another substrate of the liquid crystal display panel;

a conductive tape to electrically connect the second transparent conductive layer to one surface of the touch output pad;

a printed circuit board on which the driving voltage supply circuit is mounted; and

a flexible wiring film to electrically connect another surface of the touch output pad to the printed circuit board.

9. The liquid crystal display of claim 6, wherein the signal transmitting unit includes:

a printed circuit board on which the driving voltage supply circuit is mounted; and

a flexible wiring film to electrically connect the second transparent conductive layer to the printed circuit board.

10. A liquid crystal display comprising:

a liquid crystal display panel including a pixel array that displays an image and touch sensors that sense a touch position depending on an amount of receiving light;

a polarizing plate on one substrate of the liquid crystal display panel transmitting display light, the polarizing plate including a conductive layer;

a driving voltage supply circuit to generate a driving voltage required to perform light sensing operations of the touch sensors during a touch period based on changes in an amount of surface charge of the conductive layer depending on whether or not the polarizing plate is touched; and

a signal transmitting unit to electrically connect the conductive layer to the driving voltage supply circuit.

11. The liquid crystal display of claim 10, wherein when a user touches the polarizing plate with his or her finger, a dielectric layer on the conductive layer serves as a dielectric to form an equivalent capacitor between the user'"'"'s finger and the conductive layer,

wherein the amount of surface charge of the conductive layer has a different value during touch and non-touch operations.

12. The liquid crystal display of claim 10, wherein the signal transmitting unit includes:

a touch output pad on another substrate of the liquid crystal display panel;

a conductive tape to electrically connect the conductive layer to one surface of the touch output pad;

a printed circuit board on which the driving voltage supply circuit is mounted; and

a flexible wiring film to electrically connect another surface of the touch output pad to the printed circuit board.

13. The liquid crystal display of claim 10, wherein the signal transmitting unit includes:

a printed circuit board on which the driving voltage supply circuit is mounted; and

a flexible wiring film to electrically connect the conductive layer to the printed circuit board.