Method of fabricating touch panel

• US 8,674,953 B2
• Filed: 04/27/2010
• Issued: 03/18/2014
• Est. Priority Date: 12/21/2009
• Status: Active Grant

• Current Assignee: AU Optronics Corporation
• Original Assignee: AU Optronics Corporation
• Inventors: Lu, Ying-Chi, Huang, Shu-Hui, Chou, Shih-Po, Lee, Seok-Lyul
• Primary Examiner(s): Eisen, Alexander
• Assistant Examiner(s): MISHLER, ROBIN J
• Application Number:
  US12/768,716
• Publication Number:
  US 20110148780A1
• Time in Patent Office: 1,421 Days
• Field of Search: 345137-178
• US Class Current: 345/173
• CPC Class Codes: G06F 2203/04103 Manufacturing, i.e. details related to manufacturing processes specially suited for touch sensitive devices
• CPC Class Codes: G06F 2203/04111 Cross over in capacitive digitiser, i.e. details of structures for connecting electrodes of the sensing pattern where the connections cross each other, e.g. bridge structures comprising an insulating layer, or vias through substrate
• 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
• CPC Class Codes: H05K 2201/0326 Inorganic, non-metallic conductor, e.g. indium-tin oxide [ITO]
• CPC Class Codes: H05K 2203/0568 Resist used for applying paste, ink or powder
• CPC Class Codes: H05K 3/061 Etching masks
• CPC Class Codes: H05K 3/4685 Manufacturing of cross-over conductors
• CPC Class Codes: Y10T 29/49124 On flat or curved insulated base, e.g., printed circuit, etc.

Abstract

A method of fabricating touch panel includes the following steps. A base is provided. A first transparent conductive layer is formed on the base. A first screen printing process is performed to form a first patterned sacrificial layer on the first transparent conductive layer, and the first patterned sacrificial layer is used to pattern the first transparent conductive layer to form a patterned sensing pad layer. A second screen printing process is carried out to form a patterned insulating layer. A second transparent conductive layer is formed on the base. A third screen printing process is performed to form a second patterned sacrificial layer, and the second patterned sacrificial layer is used to pattern the second transparent conductive layer to form a patterned bridge line layer.

Claims

1. A method of fabricating a touch panel, comprising:

providing a base comprising a sensing region;

forming a first transparent conductive layer made of an amorphous metal oxide in the sensing region of the base;

patterning the first transparent conductive layer to form a patterned sensing pad layer by performing a first screen printing process using a first patterned sacrificial layer;

performing a first annealing process to transform the amorphous metal oxide of the first transparent conductive layer into a polycrystalline metal oxide;

forming a patterned insulating layer in the sensing region of the base by performing a second screen printing process;

forming a second transparent conductive layer in the sensing region of the base; and

patterning the second transparent conductive layer to form a patterned bridge line layer by performing a third screen printing process using a second patterned sacrificial layer.

2. The method of claim 1, wherein the step of patterning the first transparent conductive layer comprises forming a patterned etching resistance layer served as the first patterned sacrificial layer, and performing a first etching process to remove the first transparent conductive layer which is not covered by the patterned etching resistance layer.

3. The method of claim 1, wherein the step of patterning the first transparent conductive layer comprises forming a patterned etching paste layer served as the first patterned sacrificial layer, and removing the first transparent conductive layer below the patterned etching paste layer by using the patterned etching paste layer.

4. The method of claim 1, wherein the step of patterning the second transparent conductive layer comprises forming a patterned etching resistance layer served as the second patterned sacrificial layer, and performing a second etching process to remove the second transparent conductive layer which is not covered by the patterned etching resistance layer.

5. The method of claim 1, wherein the step of patterning the second transparent conductive layer comprises forming a patterned etching paste layer served as the second patterned sacrificial layer, and removing the second transparent conductive layer below the patterned etching paste layer by using the patterned etching paste layer.

6. The method of claim 1, comprising the sequential steps of:

(a) providing the base comprising the sensing region;

(b) forming the first transparent conductive layer in the sensing region of the base;

(c) patterning the first transparent conductive layer to form the patterned sensing pad layer by performing the first screen printing process using the first patterned sacrificial layer;

(d) forming the patterned insulating layer in the sensing region of the base by performing the second screen printing process;

(e) forming the second transparent conductive layer in the sensing region of the base; and

(f) patterning the second transparent conductive layer to form the patterned bridge line layer by performing the third screen printing process using the second patterned sacrificial layer.

7. The method of claim 1, comprising the sequential steps of:

(a) providing the base comprising the sensing region;

(b) forming the second transparent conductive layer in the sensing region of the base;

(c) patterning the second transparent conductive layer to form the patterned bridge line layer by performing the third screen printing process using the second patterned sacrificial layer;

(d) forming the patterned insulating layer in the sensing region of the base by performing the second screen printing process;

(e) forming the first transparent conductive layer in the sensing region of the base; and

(f) patterning the first transparent conductive layer to form the patterned sensing pad layer by performing the first screen printing process using the first patterned sacrificial layer.

8. The method of claim 1, further comprising performing a second annealing process after forming the patterned bridge line layer.

9. The method of claim 1, wherein the patterned sensing pad layer comprises a plurality of sensing pads, a gap is disposed between two adjacent sensing pads, and the gap is substantially between 30 micrometers and 500 micrometers.

10. The method of claim 1, wherein the patterned insulating layer comprises a plurality of insulating islands, the patterned bridge line layer comprises a plurality of bridge lines, and each of the insulating islands is corresponding to each of the bridge lines respectively.

11. The method of claim 10, wherein a line width of each of the bridge lines is substantially between 50 micrometers and 500 micrometers.

12. The method of claim 10, wherein each of the insulating islands comprises a side edge, and each of the bridge lines comprises a side edge, and a distance between a side edge of each of the insulating islands and a side edge of each of the bridge lines corresponding to the side edge of each of the insulating islands is substantially between 50 micrometers and 500 micrometers.

13. The method of claim 1, further comprising performing a fourth screen printing process to form a plurality of connecting conductive wires in a peripheral region of the base, wherein the connecting conductive wires are electrically connected to the patterned sensing pad layer.

14. The method of claim 13, wherein a line width of each of the connecting conductive wires is substantially between 10 micrometers and 300 micrometers, and a thickness of each of the connecting conductive wires is substantially between 1 micrometer and 10 micrometers.

15. The method of claim 1, wherein the base comprises a display panel.

16. The method of claim 1, wherein the base comprises an auxiliary substrate.

17. The method of claim 16, further comprising pasting the auxiliary substrate onto a display panel.

18. The method of claim 1, wherein the base comprises a glass substrate.

19. The method of claim 18, further comprising assembling the glass substrate and another substrate into a touch display panel.