Projected-capacitive (PCAP) touchscreen
Various configurations and arrangements for touchscreens are disclosed to accommodate for one or more optical discontinuities that can be present within these touchscreens. When the one or more optical discontinuities are present, these configurations and arrangements of the touchscreens present a single layer of transparent conductive material that can be difficult to perceive by a human eye when viewing the touchscreens. Additionally, various edge correction techniques are disclosed to adjust mutual capacitances along a perimeter of the touchscreens. These edge correction techniques adjust mutual capacitances such that the values of the mutual capacitances are substantially uniform throughout.
1. A method comprising:
providing a first and a second transparent substrate surface;
disposing first electrode patterns on the first transparent substrate surface using a fabrication process with an etch resolution, the first electrode patterns comprising: a first electrode pad and a first floating transparent island;
disposing second electrode patterns on the second transparent substrate surface using the fabrication process, the second electrode patterns comprising: a second electrode pad and a second floating transparent island,
wherein the first floating transparent island is horizontally between the second electrode pad and the second floating transparent island without a horizontal gap with the second electrode pad and the second floating transparent island, and the second floating transparent island is horizontally between the first electrode pad and the first floating transparent island without a horizontal gap with the first electrode pad and the first floating transparent island.
2. The method of claim 1 , wherein the fabrication process includes a screen printing process.
3. The method of claim 1 , wherein the etch resolution is approximately 200 microns.
4. The method of claim 1 , wherein the first and second transparent substrate surfaces comprise opposite surfaces of a transparent substrate.
5. The method of claim 4 , wherein the transparent substrate comprises a first transparent substrate and a second transparent substrate, the first transparent substrate attached to the second transparent substrate by respective opposing surfaces corresponding respectively to the first and second transparent substrate surfaces.
6. The method of claim 1 , wherein the first electrode pad comprises a diamond shape.
7. The method of claim 1 , wherein the first electrode patterns comprise a plurality of electrodes.
8. The method of claim 7 , wherein a center-to-center spacing between adjacent electrodes of the plurality of electrodes is substantially between 5 and 7 millimeters.
9. The method of claim 8 , wherein a width of the first floating transparent island is at least a factor of ten smaller than the center-to-center spacing.
10. The method of claim 1 , wherein the etch resolution ranges between 200 and 500 microns in width.
11. The method of claim 1 , wherein a first boundary of the first floating transparent island is substantially aligned horizontally with a boundary of the second electrode pad and a second boundary of the first floating transparent island is substantially aligned horizontally with a first boundary of the second floating transparent island, and
wherein a second boundary of the second floating transparent island is substantially aligned horizontally with a boundary of the first electrode pad.
12. The method of claim 1 , wherein the first and second electrode patterns are disposed to reduce optical discontinuities among the first and second electrode pads and the first and second floating transparent islands.