RC matching in a touch screen

• US 9,367,188 B2
• Filed: 05/23/2014
• Issued: 06/14/2016
• Est. Priority Date: 05/23/2014
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Lee, Szu-Hsien, Yang, Byung Duk, Huang, Chun-Yao, Kim, Kyung Wook, Chang, Shih Chang
• Primary Examiner(s): Okebato, Sahlu
• Application Number:
  US14/286,718
• Publication Number:
  US 20150338951A1
• Time in Patent Office: 753 Days
• US Class Current: 1/1
• CPC Class Codes: G06F 3/04166 Details of scanning methods, e.g. sampling time, grouping of sub areas or time sharing with display driving Synchronisation with the driving of the display or the backlighting unit to avoid interferences generated internally G06F3/04184
• 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
• CPC Class Codes: Y10T 29/49107 Fuse making

Abstract

A touch screen. In some examples, the touch screen can comprise a first element coupled to a first sense connection, and a second element coupled to a second sense connection. In some examples, the first and second sense connections can be configured such that a load presented by the first sense connection and the first element is substantially equal to a load presented by the second sense connection and the second element. In some examples, the first and second sense connections can comprise detour routing configured such that a resistance of the first sense connection is substantially equal to a resistance of the second sense connection. In some examples, the first and second sense connections can be coupled to dummy routing configured such that a first capacitance presented by the first sense connection is substantially equal to a second capacitance presented by the second sense connection.

Claims

1. A touch screen comprising:

a first element of a plurality of elements, the first element coupled to a first sense connection;

a second element of the plurality of elements, the second element coupled to a second sense connection;

first dummy routing coupled to the first sense connection, the first dummy routing overlapping one or more elements of the plurality of elements; and

second dummy routing coupled to the second sense connection,

wherein the first and second sense connections and the first dummy routing are configured such that a load presented by the first sense connection and the first element is substantially equal to a load presented by the second sense connection and the second element, and

the first dummy routing and the second dummy routing are configured such that a first capacitance presented by the first sense connection is substantially equal to a second capacitance presented by the second sense connection.

2. The touch screen of claim 1, wherein:

the touch screen comprises a self-capacitance touch screen, and

the first and second elements comprise distinct touch pixel electrodes of the self-capacitance touch screen.

3. The touch screen of claim 1, wherein:

the first sense connection and the second sense connection are configured to couple the first element and the second element, respectively, to a location on the touch screen, and

the first element is disposed a first distance from the location on the touch screen, and the second element is disposed a second distance from the location on the touch screen, the first distance being different than the second distance.

4. The touch screen of claim 3, wherein the location comprises a flex circuit connection area.

5. The touch screen of claim 3, wherein the location comprises sense channels.

6. The touch screen of claim 1, wherein:

the first sense connection comprises a first detour routing,

the second sense connection comprises a second detour routing, and

the first detour routing and the second detour routing are configured such that a resistance of the first sense connection is substantially equal to a resistance of the second sense connection.

7. The touch screen of claim 6, wherein a total length of the first sense connection including the first detour routing substantially equals a total length of the second sense connection including the second detour routing.

8. The touch screen of claim 1, wherein the first and second capacitances each include:

a capacitance between the first sense connection and the second element,

a capacitance between the first dummy routing and the second element,

a capacitance between the second sense connection and the first element, and

a capacitance between the second dummy routing and the first element.

9. The touch screen of claim 1, wherein:

the first element overlaps with the second sense connection a first number of times,

the first element overlaps with the second dummy routing a second number of times,

the second element overlaps with the first sense connection a third number of times,

the second element overlaps with the first dummy routing a fourth number of times, and

a sum of the first and second numbers equals a sum of the third and fourth numbers.

10. The touch screen of claim 1, wherein the first dummy routing is configured so as to not alter a first resistance of the first sense connection, and the second dummy routing is configured so as to not alter a second resistance of the second sense connection.

11. The touch screen of claim 1, wherein:

the first sense connection comprises a first portion and a second portion, the first portion including a first number of lines, and the second portion including a second number of lines, different from the first number of lines, and

the second sense connection comprises a third portion and a fourth portion, the third portion including a third number of lines, and the fourth portion including a fourth number of lines, different from the third number of lines.

12. The touch screen of claim 11, wherein:

the first number equals the third number, and the second number equals the fourth number.

24. The touch screen of claim 1, wherein:

the first sense connection is disposed along a first axis on the touch screen between a first location and a second location,

the first sense connection is coupled to sense circuitry at the first location,

the first dummy routing is coupled to the first sense connection at the second location, and

the first dummy routing is disposed along the first axis.

25. The touch screen of claim 1, wherein:

the first sense connection comprises a first conductive trace pattern, and

the first dummy routing comprises a second conductive trace pattern, corresponding to the first conductive trace pattern.

26. The touch screen of claim 25, wherein:

the first sense connection comprises a first number of parallel first conductive traces, and

the first dummy routing comprises the first number of parallel second conductive traces.

27. The touch screen of claim 1, wherein:

the first and second sense connections and the first dummy routing are configured such that a resistive and capacitive load presented by the first sense connection and the first element is substantially equal to a resistive and capacitive load presented by the second sense connection and the second element.

28. The touch screen of claim 10, wherein:

the first sense connection is configured to conduct a DC electrical current, and

the first dummy routing is configured not to conduct a DC electrical current.

13. A method for fabricating a touch screen, the method comprising:

forming a first element of a plurality of elements;

forming a first sense connection coupled to the first element;

forming a second element of the plurality of elements;

forming a second sense connection coupled to the second element;

forming a first dummy routing coupled to the first sense connection, the first dummy routing overlapping one or more elements of the plurality of elements; and

forming second dummy routing coupled to the second sense connection,

wherein the first and second sense connections and the first dummy routing are configured such that a load presented by the first sense connection and the first element is substantially equal to a load presented by the second sense connection and the second element, and

the first dummy routing and the second dummy routing are configured such that a first capacitance presented by the first sense connection is substantially equal to a second capacitance presented by the second sense connection.

14. The method of claim 13, wherein:

the touch screen comprises a self-capacitance touch screen, and

the first and second elements comprise distinct touch pixel electrodes of the self-capacitance touch screen.

15. The method of claim 13, wherein:

the first sense connection and the second sense connection are configured to couple the first element and the second element, respectively, to a location on the touch screen, and

forming the first element comprises forming the first element disposed a first distance from the location on the touch screen, and forming the second element comprises forming the second element disposed a second distance from the location on the touch screen, the first distance being different than the second distance.

16. The method of claim 15, wherein the location comprises a flex circuit connection area.

17. The method of claim 13, wherein:

forming the first sense connection comprises forming the first sense connection including a first detour routing,

forming the second sense connection comprises forming the second sense connection including a second detour routing, and

the first detour routing and the second detour routing are configured such that a resistance of the first sense connection is substantially equal to a resistance of the second sense connection.

18. The method of claim 17, wherein a total length of the first sense connection including the first detour routing substantially equals a total length of the second sense connection including the second detour routing.

19. The method of claim 13, wherein the first and second capacitances each include:

a capacitance between the first sense connection and the second element,

a capacitance between the first dummy routing and the second element,

a capacitance between the second sense connection and the first element, and

a capacitance between the second dummy routing and the first element.

20. The method of claim 13, wherein:

the first element overlaps with the second sense connection a first number of times,

the first element overlaps with the second dummy routing a second number of times,

the second element overlaps with the first sense connection a third number of times,

the second element overlaps with the first dummy routing a fourth number of times, and

a sum of the first and second numbers equals a sum of the third and fourth numbers.

21. The method of claim 13, wherein the first dummy routing is configured so as to not alter a first resistance of the first sense connection, and the second dummy routing is configured so as to not alter a second resistance of the second sense connection.

22. The method of claim 13, wherein:

forming the first sense connection comprises forming the first sense connection including a first portion and a second portion, the first portion including a first number of lines, and the second portion including a second number of lines, different from the first number of lines, and

forming the second sense connection comprises forming the second sense connection including a third portion and a fourth portion, the third portion including a third number of lines, and the fourth portion including a fourth number of lines, different from the third number of lines.

23. The method of claim 22, wherein:

the first number equals the third number, and the second number equals the fourth number.

29. The method of claim 13, wherein

the first sense connection is disposed along a first axis on the touch screen between a first location and a second location,

the first sense connection is coupled to sense circuitry at the first location,

the first dummy routing is coupled to the first sense connection at the second location, and

the first dummy routing is disposed along the first axis.

30. The method of claim 13, wherein

the first sense connection comprises a first conductive trace pattern, and

the first dummy routing comprises a second conductive trace pattern, corresponding to the first conductive trace pattern.

31. The method of claim 30, wherein

the first sense connection comprises a first number of parallel first conductive traces, and

the first dummy routing comprises the first number of parallel second conductive traces.

32. The method of claim 13, wherein:

the first and second sense connections are configured such that a resistive and capacitive load presented by the first sense connection and the first element is substantially equal to a resistive and capacitive load presented by the second sense connection and the second element.

33. The method of claim 21, wherein:

the first sense connection is configured to conduct a DC electrical current; and

the first dummy routing is configured not to conduct a DC electrical current.