TOUCH SCREEN DISPLAY UNIFORMITY

• US 20160266693A1
• Filed: 03/09/2016
• Published: 09/15/2016
• Est. Priority Date: 03/09/2015
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: CHEN, Yu Cheng, OSAWA, Hiroshi, LIN, Shang-Chih, YEH, Shin-Hung, GHARGHI, Majid, YAMASHITA, Keitaro, JAMSHIDI-ROUDBARI, Abbas, CHANG, Shih-Chang, CHANG, Ting-Kuo
• Granted Patent: US 10,048,788 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G02F 1/13338 Input devices, e.g. touch panels
• CPC Class Codes: G02F 1/1343 Electrodes reflective electrodes G02F1/133553
• CPC Class Codes: G06F 3/0412 Digitisers structurally integrated in a display
• CPC Class Codes: G06F 3/0418 for error correction or compensation, e.g. based on parallax, calibration or alignment
• CPC Class Codes: G06F 3/0443 using a single layer of sensing electrodes

Abstract

Improvement of visual uniformity of an integrated touch screen display is provided. A touch screen can include common electrodes separated by gaps in a Vcom layer. To improve visual non-uniformity in the display resulting from the gaps, a first set of semi-transparent dummy features (primary-dummy features) can be formed on a second layer at the locations of the gaps, and a second set of dummy features (supplementary-dummy features) can also be formed on the second layer or another layer to mitigate low spatial resolution of the primary-dummy features and/or non-uniform spacing of the primary-dummy features. In some examples, holes or slits can be formed in the Vcom layer at areas of the supplementary-dummy features to further improve visual uniformity.

Claims

1. A touch screen comprising:

a plurality of common electrodes formed of a first conductive material;

a plurality of dummy features, including;

a set of primary-dummy features formed of a second conductive material, and

a set of supplementary-dummy features formed of a third conductive material;

wherein;

at least one of the primary-dummy features is disposed so as to overlap with one or more gaps between the plurality of common electrodes, and

at least one of the supplementary-dummy features is disposed so as to make a distance between one or more adjacent pairs of the plurality of dummy features equal in a first direction.

2. The touch screen of claim 1, wherein the distance between the one or more adjacent pairs of the plurality of dummy features is less than a smallest distance between any of one or more immediately adjacent pairs of primary-dummy features in the first direction.

3. The touch screen of claim 1, wherein the length of two or more of the set of supplementary-dummy features in a second direction, perpendicular to the first direction, is equal.

4. The touch screen of claim 1, wherein a subset of the set of supplementary-dummy features are aligned in a second direction perpendicular to the first direction, and a distance in a second direction between one or more immediately adjacent pairs of the subset of supplementary-dummy features is equal.

5. The touch screen of claim 4, wherein the distance in the second direction between the one or more adjacent pairs of the subset of supplementary-dummy features is the same as a distance between a pair of common electrodes immediately adjacent in the second direction.

6. The touch screen of claim 4, wherein the subset of supplementary-dummy features are all located on a single common electrode and the subset of supplementary-dummy features includes multiple supplementary-dummy features.

7. The touch screen of claim 1, wherein one or more of the supplementary-dummy features is coupled to one of the plurality of common electrodes.

8. The touch screen of claim 1, wherein the set of primary-dummy features is coupled to one another in a border area of the touch screen.

9. The touch screen of claim 1, wherein one or more of the set of primary-dummy features is coupled to a ground.

10. The touch screen of claim 1, wherein one or more of the set of primary-dummy features is electrically floating.

11. The touch screen of claim 1, wherein a first plurality of common electrodes form one or more drive lines and a second plurality of common electrodes form one or more sense lines.

12. The touch screen of claim 11, wherein a first plurality of supplementary-dummy features are coupled to the one or more drive lines and a second plurality of supplementary-dummy features are coupled to the one or more sense lines.

13. The touch screen of claim 1, wherein one or more common electrodes of the plurality of common electrodes includes a plurality of holes.

14. The touch screen of claim 13, wherein one or more supplementary-dummy features of the set of supplementary-dummy features is disposed as to be over one or more of the plurality of holes.

15. The touch screen of claim 13, wherein a pair of holes of the plurality of holes is separated in the first direction by a distance equal to the distance between the one or more adjacent pairs of the plurality of dummy features.

16. The touch screen of claim 13, wherein:

the plurality of holes each have a rectangular shape and are formed as to each have a first width;

the one or more gaps each have a second width; and

the first width is equal to the second width.

17. The touch screen of claim 13, further comprising a first common electrode, the first common electrode including a first and second hole of the plurality of holes, wherein:

the first and second hole are aligned in a second direction orthogonal to the first;

a first supplementary-dummy feature of the set of supplementary-dummy features is disposed over the first and second hole; and

the first supplementary-dummy feature is coupled to the first common electrode at a location between the first and second hole.

18. The touch screen of claim 1, wherein the first conductive material is the same as the second conductive material.

19. The touch screen of claim 1, wherein the second conductive material is the same as the third conductive material.

20. The touch screen of claim 1 further comprising a plurality of pixel electrodes formed of the second conductive material and on a same layer as the plurality of dummy features.

21. The touch screen of claim 1 further comprising a plurality of common voltage lines formed of the second conductive material and on a same layer as the plurality of dummy features.

22. The touch screen of claim 1, wherein the plurality of common electrodes are configured to operate as touch sensing elements during a touch sensing phase and to operate as elements of a display during a display phase.

23. A method of forming a touch screen, comprising:

on a first layer, depositing a first conductive material to form a plurality of common electrodes;

on a second layer, depositing a second conductive material to form a set of primary-dummy features;

on the second layer, depositing a third conductive material to form a set of supplementary-dummy features parallel to the primary-dummy features;

wherein;

each of the primary-dummy features is disposed over one or more gaps between the plurality of common electrodes, and

each of the supplementary-dummy features is disposed over at least a portion of the common electrodes.

24. The method of claim 23, wherein a smallest distance between any two immediately adjacent primary-dummy features is larger than a smallest distance between any two immediately adjacent primary-dummy features or supplementary-dummy features.

25. The method of claim 23, wherein depositing the third conductive material on the second layer includes forming two supplementary-dummy features, both of which at least partially overlap a same common electrode.

26. The method of claim 25, wherein the two supplementary-dummy features are parallel in a first direction and separated by a distance in a second direction, perpendicular to the first direction.

27. The method of claim 25, wherein the two supplementary-dummy features are aligned in a first direction along a length of the two supplementary-dummy features.

28. The method of claim 23, wherein one or more supplementary-dummy features are coupled to one or more common electrodes.

29. The method of claim 23, further comprising, on the second layer, depositing the second conductive material to form one or more display pixel elements.

30. The method of claim 23, further comprising, on the second layer, depositing the second conductive material to form one or more common voltage lines.

31. The method of claim 23, wherein:

the first conductive material is deposited such that one or more of the plurality of common electrodes each include a plurality of holes in the first conductive material; and

one or more of the supplementary-dummy features is disposed over one or more of the plurality of holes.

32. The method of claim 31, wherein one or more of the plurality of holes is of a rectangular shape having a length and a width, the length running parallel to the supplementary-dummy features, and the width being equal to a width of each of the one or more gaps between the plurality of electrodes.