TOUCHSCREEN WITH BRIDGED FORCE-SENSITIVE RESISTORS

• US 20130278542A1
• Filed: 04/23/2012
• Published: 10/24/2013
• Est. Priority Date: 04/23/2012
• Status: Active Grant

• Current Assignee: Snaptrack Incorporated (Qualcomm, Inc.)
• Original Assignee: Qualcomm MEMS Technologies Incorporated (Qualcomm, Inc.)
• Inventors: Stephanou, Philip Jason, Buchan, Nicholas Ian, Burns, David William, Lavery, Kristopher Andrew, Ganapathi, Srinivasan Kodaganallur
• Granted Patent: US 9,024,910 B2
• Time in Patent Office: Days
• US Class Current: 345/174
• CPC Class Codes: G06F 2203/04103 Manufacturing, i.e. details related to manufacturing processes specially suited for touch sensitive devices
• CPC Class Codes: G06F 2203/04106 Multi-sensing digitiser, i.e. digitiser using at least two different sensing technologies simultaneously or alternatively, e.g. for detecting pen and finger, for saving power or for improving position detection
• 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 3/0414 using force sensing means to determine a position
• CPC Class Codes: G06F 3/044 by capacitive means

Abstract

A touch sensor may include a digital resistive touch (DRT) sensor architecture that is substantially free of air gaps. The DRT touch sensor may include a layer of force-sensitive resistor (FSR) material on an array of row and column electrodes. The electrodes may be formed on a substantially transparent substrate. Near the intersection of each row and column, one or more thin transparent patterned conductive bridges may be situated above the FSR. The conductive bridges may be configured for electrical connection with row and column electrodes when force is applied to the conductive bridge or surface of the touch sensor. Some touch sensors may include both DRT and projected capacitive touch (PCT) functionality.

Claims

1. A touch sensor apparatus, comprising:

a substrate;

a plurality of first electrodes disposed on the substrate;

a dielectric layer disposed on the plurality of first electrodes;

a plurality of second electrodes disposed on the dielectric layer;

a plurality of intermediate conductors disposed on the dielectric layer and configured for electrical communication with the first electrodes through vias formed in the dielectric layer;

a layer of force-sensitive resistor (FSR) material disposed on the second electrodes and the intermediate conductors; and

a plurality of conductive bridges disposed on the FSR material, each of the conductive bridges being disposed above at least one of the intermediate conductors, wherein the FSR material is configured to form at least one substantially vertical electrical connection between one of the conductive bridges, one of the second electrodes, and one of the intermediate conductors when a force is applied to the FSR material.

2. The apparatus of claim 1, wherein the substrate is substantially transparent.

3. The apparatus of claim 1, further including a fixed resistor disposed between one of the intermediate conductors and one of the first electrodes.

4. The apparatus of claim 1, wherein an open region between the conductive bridges at least partially exposes a projected capacitive touch (PCT) area of the first electrodes and the second electrodes and wherein the touch sensor apparatus is configured for enabling the measurement of changes in mutual capacitance between the first electrodes and the second electrodes.

5. The apparatus of claim 4, wherein at least one of the first electrodes or the second electrodes includes a conductive portion in the exposed PCT area.

6. The apparatus of claim 1, wherein some of the conductive bridges are disposed, at least in part, above one of the second electrodes.

7. The apparatus of claim 1, wherein the conductive bridges are formed into at least one of islands, segmented strips, curvilinear stripes, curvilinear segments, diamond shapes, hollowed geometries, or framed geometries.

8. The apparatus of claim 1, wherein at least one of the first electrodes, the second electrodes, or the intermediate conductors include branches.

9. The apparatus of claim 8, wherein the branches are formed into at least one of L-shapes, spirals, or interdigitated shapes.

10. The apparatus of claim 8, wherein the intermediate conductor branches are interdigitated with first electrode branches or second electrode branches.

11. The apparatus of claim 1, wherein at least one of the first electrodes, the intermediate conductors, or the second electrodes is formed of a substantially transparent conductive material.

12. The apparatus of claim 1, wherein at least one of the first electrodes or the second electrodes includes a substantially transparent conductive material and a conductive metal.

13. The apparatus of claim 1, wherein at least a portion of one of the first electrodes or the second electrodes is formed of metal.

14. The apparatus of claim 1, further including a force-spreading layer disposed above the conductive bridges and the FSR material.

15. The apparatus of claim 1, further including conductive adhesive material disposed between the FSR material and at least one of the conductive bridges, the intermediate conductors, the second electrodes, a flexible layer, a dielectric layer, or a force-spreading layer.

16. The apparatus of claim 15, wherein the conductive adhesive material is substantially transparent.

17. The apparatus of claim 1, wherein the second electrodes include row electrodes and column electrodes, and wherein the first electrodes include jumpers configured to form electrical connections along at least one of the row electrodes or the column electrodes.

18. The apparatus of claim 1, further comprising:

a display;

a processor that is configured to communicate with the display, the processor being configured to process image data; and

a memory device that is configured to communicate with the processor.

19. The apparatus of claim 18, further comprising:

a driver circuit configured to send at least one signal to the display; and

a controller configured to send at least a portion of the image data to the driver circuit.

20. The apparatus of claim 18, further comprising:

an image source module configured to send the image data to the processor, wherein the image source module includes at least one of a receiver, a transceiver or a transmitter.

21. The apparatus of claim 18, further comprising:

an input device configured to receive input data and to communicate the input data to the processor.

22. The apparatus of claim 18, further comprising:

a touch controller configured for communication with the processor; and

routing wires configured for connecting at least one of the first electrodes or the second electrodes to the touch controller.

23. An apparatus, comprising:

substrate means;

first electrode means disposed on the substrate means;

dielectric means disposed on the first electrode means;

second electrode means disposed on the dielectric means;

intermediate conductor means disposed on the dielectric means and configured for electrical communication with the first electrode means;

force-sensitive resistor (FSR) means disposed on the second electrode means and the intermediate conductor means; and

conductive bridge means disposed on the FSR means and disposed above at least a portion of the intermediate conductor means, wherein the FSR means includes means for making at least one substantially vertical electrical connection between an instance of the conductive bridge means, an instance of the second electrode means, and an instance of the intermediate conductor means when a force is applied to the FSR means.

24. The apparatus of claim 23, further including fixed resistor means disposed between the intermediate conductor means and the first electrode means.

25. The apparatus of claim 23, wherein the conductive bridge means at least partially exposes a projected capacitive touch (PCT) area of the first electrode means and the second electrode means and wherein the apparatus is configured for measuring changes in mutual capacitance between the first electrode means and the second electrode means.

26. The apparatus of claim 25, wherein at least one of the first electrode means or the second electrode means includes a conductive portion in the exposed PCT area.

27. A method of fabricating a touch sensor apparatus, the method comprising:

forming a plurality of first electrodes on a substrate;

forming a dielectric layer on the plurality of first electrodes;

forming vias in the dielectric layer;

forming a plurality of second electrodes on the dielectric layer;

forming a plurality of intermediate conductors on the dielectric layer, the intermediate conductors being configured for electrical communication with the first electrodes through the vias;

disposing a layer of anisotropic force-sensitive resistor (FSR) material on the second electrodes and the intermediate conductors; and

forming a plurality of conductive bridges on the FSR material, each of the conductive bridges being disposed above at least one of the intermediate conductors, wherein the FSR material is configured to form at least one substantially vertical electrical connection between one of the conductive bridges, one of the second electrodes, and one of the intermediate conductors when a force is applied to the FSR material.

28. The method of claim 27, further including disposing a fixed resistor between one of the intermediate conductors and one of the first electrodes.

29. The method of claim 27, wherein an open region between the conductive bridges at least partially exposes a projected capacitive touch (PCT) area of the first electrodes and the second electrodes, further including configuring the touch sensor apparatus for measuring changes in mutual capacitance between the first electrodes and the second electrodes.

30. The method of claim 29, wherein at least one of the first electrodes or the second electrodes includes a conductive portion in the exposed PCT area.

31. The method of claim 30, wherein the conductive portion is formed, at least in part, of a conductive metal.

32. The method of claim 27, wherein forming the plurality of conductive bridges involves forming some of the conductive bridges to extend above at least one of the second electrodes.