Liquid crystal display device associated with touch panel and method for fabricating the same

• US 8,610,859 B2
• Filed: 06/09/2011
• Issued: 12/17/2013
• Est. Priority Date: 06/10/2010
• Status: Active Grant

• Current Assignee: LG Display Co., Ltd.
• Original Assignee: LG Display Co., Ltd.
• Inventors: Kim, Tae-Hwan, Kim, Tae-Hoon
• Primary Examiner(s): Stahl, Mike
• Application Number:
  US13/156,953
• Publication Number:
  US 20110304571A1
• Time in Patent Office: 922 Days
• Field of Search: None
• US Class Current: 349/139
• CPC Class Codes: G02F 1/13338 Input devices, e.g. touch panels
• CPC Class Codes: G06F 2203/04103 Manufacturing, i.e. details related to manufacturing processes specially suited for touch sensitive devices
• CPC Class Codes: G06F 3/0412 Digitisers structurally integrated in a display
• CPC Class Codes: G06F 3/0445 using two or more layers of sensing electrodes, e.g. using two layers of electrodes separated by a dielectric layer
• CPC Class Codes: G06F 3/0446 using a grid-like structure of electrodes in at least two directions, e.g. using row and column electrodes

Abstract

The present invention relates to a liquid crystal display device associated with a touch panel, the device includes a liquid crystal panel having opposite first and second substrates, and a liquid crystal layer formed between the first and second substrates, a plurality of driving electrodes arranged on an outer surface of the second substrate in one direction spaced from one another, a first polarizing plate formed on the outer surface of the second substrate including the driving electrodes, a third substrate opposite to the first polarizing plate, and a plurality of sensing electrodes formed on a surface of the third substrate opposite to the first polarizing plate perpendicular to the driving electrodes spaced from one another.

Claims

1. A liquid crystal display device associated with a touch panel, the device comprising:

a liquid crystal panel having opposite first and second substrates, and a liquid crystal layer formed between the first and second substrates;

a plurality of driving electrodes arranged on an outer surface of the second substrate in one direction spaced from one another;

a first polarizing plate formed on the outer surface of the second substrate including the driving electrodes;

a third substrate opposite to the first polarizing plate;

a plurality of sensing electrodes formed on a surface of the third substrate opposite to the first polarizing plate perpendicular to the driving electrodes spaced from one another;

driving pad electrodes formed at an edge of the outer surface of the second substrate connected to the driving electrodes with first routing lines respectively, and a first FPC (Flexible Printed Circuit) connected to the driving pad electrodes; and

sensing pad electrodes formed on a surface of the third substrate opposite to the first polarizing plate connected to the sensing electrodes with second routing lines respectively, and a second FPC connected to the sensing pad electrodes.

2. The device as claimed in claim 1, wherein both the driving electrodes and the sensing electrodes are transparent electrodes.

3. The device as claimed in claim 1, wherein the driving electrodes have sheet resistance of below 100Ω

/□

.

4. The device as claimed in claim 1, wherein the driving electrodes have a square wave applied thereto in succession.

5. The device as claimed in claim 4, wherein the square wave includes two potential levels of a constant voltage and a ground voltage.

6. The device as claimed in claim 1, wherein the first FPC and the second FPC are connected to a driving circuit board of the liquid crystal panel.

7. The device as claimed in claim 6, wherein the first FPC and the second FPC are connected to the driving circuit board of the liquid crystal panel through connectors, respectively.

8. The device as claimed in claim 1, further comprising a touch driving IC included to the first FPC or the second FPC.

9. The device as claimed in claim 6, further comprising a touch driving IC included to the driving circuit board of the liquid crystal panel.

10. The device as claimed in claim 1, further comprising a protective film on the third substrate.

11. The device as claimed in claim 10, wherein the protective film is a glass substrate or an insulating transparent film.

12. The device as claimed in claim 1, wherein the third substrate is a glass substrate.

13. The device as claimed in claim 1, wherein the third substrate is an insulating transparent film.

14. The device as claimed in claim 1, further comprising an adhesive layer disposed between the third substrate and the first polarizing plate.

15. The device as claimed in claim 1, further comprising a closed loop of adhesion paste formed at an edge of the first polarizing plate between the third substrate and the first polarizing plate.

16. The device as claimed in claim 1, further comprising a second polarizing plate on an outer surface of the first substrate.

17. The device as claimed in claim 1, further comprising a thin film transistor array on an inner surface of the first substrate, and color filter array on an inner surface of the second substrate.

18. A method for fabricating a liquid crystal display device associated with a touch panel, the method comprising the steps of:

forming a plurality of driving electrodes in one direction spaced from one another by depositing a transparent electrode on one surface of a first substrate and patterning the transparent electrode;

turning over the first substrate, and performing a color filter array step on the other surface of the first substrate;

forming a thin film transistor array on a second substrate;

forming a liquid crystal panel by bonding the first and second substrates after forming a liquid crystal layer between the first and second substrates;

forming a first polarizing plate on the one surface of the first substrate to cover the driving electrodes;

forming a plurality of sensing electrodes on one surface of a third substrate in a direction perpendicular to the driving electrodes spaced from one another; and

bonding the third substrate to the first polarizing plate such that the one surface of the third substrate having the sensing electrodes formed thereon is opposite to the first polarizing plate.

19. The method as claimed in claim 18, further comprising the step of forming a second polarizing plate on an outer surface of the second substrate.