Touch panel assemblies and methods of manufacture

• US 9,304,347 B2
• Filed: 12/19/2012
• Issued: 04/05/2016
• Est. Priority Date: 02/27/2012
• Status: Expired due to Fees

• Current Assignee: Amazon Technologies, Inc. (Amazon.com, Inc.)
• Original Assignee: Amazon Technologies, Inc. (Amazon.com, Inc.)
• Inventors: Rowe, Gabriel Isaiah
• Primary Examiner(s): CHEN, WEN YING PATTY
• Application Number:
  US13/720,700
• Publication Number:
  US 20130235285A1
• Time in Patent Office: 1,203 Days
• Field of Search: 349/12
• US Class Current: 1/1
• CPC Class Codes: G02F 1/133331 Cover glasses
• CPC Class Codes: G02F 1/133351 Manufacturing of individual cells out of a plurality of cells, e.g. by dicing
• CPC Class Codes: G02F 1/13338 Input devices, e.g. touch panels
• CPC Class Codes: G02F 1/133514 Colour filters
• 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: H01L 33/58 Optical field-shaping elements

Abstract

A two layer touch panel structure utilizes direct-bonded touch panel and liquid crystal display (LCD) stackups for devices like tablets and computers. The top surface of a color filter and a receive conducting layer are placed close to the surface of the stackup. Placing a layer of conductive material on top of the color filter, on top of the polarizer, or on the cover glass can enable the process to be greatly simplified and cheaper than conventional processes, while maintaining excellent electrical and touch performance, and reducing ITO pattern visibility. Such a process also can utilize a large color filter, enabling significantly more pieces to be formed from a single stack and thus further improving efficiency and cost.

Claims

1. A method of forming a touch panel assembly, comprising:

depositing a layer of conductive material on a first surface of a glass sheet;

patterning the conductive material into a first set of electrodes;

forming a color filter layer on a second surface of the glass sheet, the second surface being opposite the first surface;

forming a thin film transistor (TFT) display layer;

connecting the thin film transistor (TFT) display layer to the color filter layer using an adhesive to form an intermediate stack;

injecting a layer of liquid crystal material into space between the TFT display layer and the color filter layer in the intermediate stack;

cutting a pattern into the intermediate stack in order to segment the intermediate stack into a plurality of cells;

bonding at least one electrical connector to the intermediate stack;

connecting a first polarizer to an upper surface of the intermediate stack and a second polarizer to a lower surface of the intermediate stack, the first polarizer having a first polarization oriented at approximately ninety degrees with respect to a second polarization of the second polarizer; and

connecting a top stack to the first polarizer to form a final stack, the top stack including at least a cover glass sheet and an upper patterned conductive layer, the upper patterned conductive layer forming a second set of electrodes.

2. The method of claim 1, further comprising:

laminating the final stack.

3. The method of claim 1, further comprising:

forming a floating electrode element between two electrodes of the first set of electrodes in the layer of conductive material, the floating electrode element being electrically isolated from the two electrodes.

4. The method of claim 1, wherein the depositing of the layer of conductive material on the first surface of the glass sheet is performed one of before or after forming the color filter layer on the second surface of the glass sheet.

5. A method of forming a touch panel assembly, comprising:

forming a pattern of electrodes in a layer of conductive material deposited on a first surface of a glass sheet;

forming a color filter layer on a second surface of the glass sheet, the second surface being opposite the first surface;

connecting a thin film transistor (TFT) display layer to the color filter layer to create an intermediate stack;

placing liquid crystal material between at least a portion of the TFT display layer and the color filter layer;

cutting a pattern into the glass sheet with the color filter layer and the TFT display layer in order to segment the glass sheet into a plurality of individual cells;

connecting at least one electrical connector to the intermediate stack;

connecting a first polarizer to an upper surface of the intermediate stack and a second polarizer to a lower surface of the intermediate stack, the first polarizer having a first polarization oriented at approximately ninety degrees with respect to a second polarization of the second polarizer; and

connecting a cover glass sheet to the connecting stack to form the touch panel assembly, the cover glass having formed thereon an upper patterned conductive layer forming a second set of electrodes.

6. The method of claim 5, further comprising:

laminating the touch panel assembly.

7. The method of claim 5, wherein connecting the at least one electrical connector to the intermediate stack includes connecting an electrical connector of the at least one electrical connector to one of the individual cells.

8. The method of claim 7, wherein each of the individual cells has a size corresponding to an associated type of display device.

9. The method of claim 5, wherein the pattern of electrodes includes a plurality of parallel strips formed into the layer of conductive material.

10. The method of claim 9, wherein the pattern of electrodes further includes a floating electrode element between a pair of the parallel strips.

11. The method of claim 10, further comprising:

adjusting a length to be used for the floating element, an increase in the length of the floating electrode reducing a likelihood of an electrical short between the pair of the parallel strips.

12. The method of claim 5, wherein the layer of conductive material comprises at least one of Indium Tin Oxide (ITO), Graphene, carbon nanotubes, or a metal mesh.

13. The method of claim 5, further comprising:

performing short testing on the pattern of electrodes before connecting at least the first polarizer.

14. A touch panel stack, comprising:

a cover glass layer;

a first polarizer positioned proximate a first surface of the cover glass layer;

a first set of electrodes formed on a second surface of the cover glass layer, the second surface being opposite the first surface;

a thin film transistor (TFT) display component;

a glass sheet positioned between the cover glass layer and the TFT display component, the glass sheet having a color filter layer formed thereon;

a liquid crystal layer between the glass sheet and the TFT display component;

a second polarizer proximate a first side of the TFT display component, the first side being opposite a second side of the TFT display component, the second side of the TFT display component being proximate the first polarizer;

a second set of electrodes positioned proximate at least one of the color filter layer, the glass sheet, or the second polarizer, wherein the second set of electrode is separated from the first set of electrodes; and

wherein at least one of the first set of electrodes or the second set of electrodes is patterned to include at least a pair of parallel strips separated by at least one floating electrode element, the at least one floating electrode element being electrically isolated from the pair of parallel strips.

15. The touch panel stack of claim 14, further comprising:

at least one connector for applying a voltage to at least one of the first set of electrodes or the second set of electrodes.

16. The touch panel stack of claim 14, further comprising:

at least one connector enabling control of a state of the liquid crystal layer, the state of the liquid crystal layer determining a transparency of the touch panel stack.

17. The touch panel stack of claim 14, wherein the touch panel stack is laminated.

18. The touch panel stack of claim 14, wherein at least one of the first set of electrodes or the second set of electrodes is formed from at least one of Indium Tin Oxide (ITO), Graphene, carbon nanotubes, or a metal mesh.

19. The touch panel stack of claim 14, wherein the first polarizer has a first polarization oriented at approximately ninety degrees with respect to a second polarization of the second polarizer.