Resistive touch sensor system and method

Patent metadata

Field	Value
Publication number	US-9465477-B2
Application number	US-201414499001-A
Country	US
Kind code	B2
Filing date	Sep 26, 2014
Priority date	Sep 27, 2013
Publication date	Oct 11, 2016
Grant date	Oct 11, 2016

Abstract

A resistive touch sensor system and method incorporating an interpolated sensor array is disclosed. The system and method utilize a touch sensor array (TSA) configured to detect proximity/contact/pressure (PCP) via a variable impedance array (VIA) electrically coupling interlinked impedance columns (IIC) coupled to an array column driver (ACD), and interlinked impedance rows (IIR) coupled to an array row sensor (ARS). The ACD is configured to select the IIC based on a column switching register (CSR) and electrically drive the IIC using a column driving source (CDS). The VIA conveys current from the driven IIC to the IIC sensed by the ARS. The ARS selects the IIR within the TSA and electrically senses the IIR state based on a row switching register (RSR). Interpolation of ARS sensed current/voltage allows accurate detection of TSA PCP and/or spatial location.

First claim

What is claimed is:

1. A resistive touch sensor system comprising:
(a) touch sensor array (TSA);
(b) array column driver (ACD);
(c) column switching register (CSR);
(d) column driving source (CDS);
(e) array row sensor (ARS);
(f) row switching register (RSR);
(g) analog to digital converter (ADC); and
(h) computing control device (CCD);
wherein:
said TSA comprises a variable impedance array (VIA) comprising VIA columns and VIA rows;
said VIA comprises a first layer having a top side and a bottom side;
said first layer comprises a force sensing material;
said VIA comprises a second layer having a top side and a bottom side;
said second layer comprises exposed coplanar drive electrodes;
said second layer further comprises coplanar sense electrodes;
said VIA is configured to electrically couple a plurality of interlinked impedance columns (IIC) within said TSA with a plurality of interlinked impedance rows (IIR) within said TSA;
said IIC further comprises a plurality of individual column impedance elements (ICIE) electrically connected in series between said drive electrodes;
said IIR further comprises a plurality of individual row impedance elements (IRIE) electrically connected in series between said sense electrodes;
said ACD is configured to select said IIC within said TSA based on said CSR;
said ACD is configured to electrically drive said selected IIC using said CDS;
said CDS is configured to power one or more of said drive electrodes while driving one or more of said drive electrodes to ground potential;
said ARS is configured to select said IIR within said TSA based on said RSR while simultaneously driving one or more of said sense electrodes to ground potential;
said ADC is configured to sense the electrical state of said selected IIR and convert said electrical state to a sensed digital value (SDV);
said electrical state is determined by the sum of current contributions of variable impedance elements within said VIA, where the current contribution of each of said variable impedance elements is determined by a voltage divider formed between the columns of said VIA, a current divider formed between the rows of said VIA, and the state of said each of said variable impedance elements, to produce a sensed current for a given row-column intersection with said VIA; and
said CCD is configured to sample said SDV from said ADC at a plurality of positions within said TSA to form a touch sensor matrix (TSM) data structure.

2. The resistive touch sensor system of claim 1 wherein said drive electrodes reside on said top side of said second layer, said sense electrodes reside on said bottom side of said second layer, and vias interconnect said sense electrodes to conductive pads on said top side of said second layer.

3. The resistive touch sensor system of claim 1 wherein said sense electrodes reside on said top side of said second layer, said drive electrodes reside on said bottom side of said second layer, and vias interconnect said drive electrodes to conductive pads on said top side of said second layer.

4. The resistive touch sensor system of claim 1 wherein said sense electrodes comprise an upper surface and a lower surface, and said upper surface of said sense electrodes are planar.

5. The resistive touch sensor system of claim 1 wherein the row/column pitch of said drive electrodes and said sense electrodes is 1 mm.

6. The resistive touch sensor system of claim 1 wherein said drive electrodes and said sense electrodes form a rectangle pattern.

7. The resistive touch sensor system of claim 1 wherein said drive electrodes and said sense electrodes form an interdigitated finger pattern.

8. The resistive touch sensor system of claim 1 wherein said drive electrodes and said sense electrodes form a rectangle pattern with every other column flipped.

9. The resistive touch sensor system of claim 1 wherein said drive electrodes and said sense electrodes form an interdigitated finger pattern with every other column flipped.

10. The resistive touch sensor system of claim 1 wherein said drive electrodes and said sense electrodes form a diamond pattern.

11. The resistive touch sensor system of claim 1 wherein said drive electrodes and said sense electrodes form a non-rectangular force sensor array.

12. The resistive touch sensor system of claim 1 wherein said first layer comprises a thin layer having a high per-square resistance to bulk resistance ratio.

13. The resistive touch sensor system of claim 1 wherein said VIA comprises sensor elements having a resistance greater than that of the IIR impedances and the IIC impedances.

14. The resistive touch sensor system of claim 1 wherein said first layer comprises a force sensing layer that is segmented with segments aligning to force sensing elements within said VIA.

15. The resistive touch sensor system of claim 1 wherein said first layer comprises a polymer loaded with conductive particles.

16. The resistive touch sensor system of claim 1 wherein said first layer comprises a force sensing layer that is patterned.

17. The resistive touch sensor system of claim 1 wherein said first layer comprises a force sensing layer that is patterned with a random or pseudo-random pattern.

18. The resistive touch sensor system of claim 1 wherein said second layer comprises traces that further comprise a force sensing material.

19. The resistive touch sensor system of claim 1 wherein said first layer comprises a force sensing layer having material selected from a group consisting of: conductive rubber; conductive foam; conductive plastic; KAPTON® loaded with conductive particles; conductive ink; a mixture of conductive particles with insulating particles; and carbon particles mixed with a polymer.

20. The resistive touch sensor system of claim 1 wherein said second layer comprises conductive traces that are coated with gold plating.

21. The resistive touch sensor system of claim 1 wherein said second layer comprises conductive traces that are coated with an electroless nickel gold (ENIG) plating.

22. The resistive touch sensor system of claim 1 wherein said second layer comprises conductive traces that are coated with a screen printed carbon.

23. The resistive touch sensor system of claim 1 wherein said second layer comprises a rigid printed circuit board (PCB).

24. The resistive touch sensor system of claim 1 wherein said second layer comprises a rigid printed circuit board (PCB) comprising FR4 material.

25. The resistive touch sensor system of claim 1 wherein said second layer comprises a flexible printed circuit board (PCB).

26. The resistive touch sensor system of claim 1 wherein said second layer comprises a printed circuit board (PCB) formed using an additive printed electronics process.

27. The resistive touch sensor system of claim 1 wherein said second layer comprises mechanically drilled vias.

28. The resistive touch sensor system of claim 1 wherein said second layer comprises laser drilled vias.

29. The resistive touch sensor system of claim 1 wherein said second layer comprises filled vias.

30. The resistive touch sensor system of claim 1 wherein said second layer comprises vias formed by openings in a printed dielectric layer.

31. The resistive touch sensor system of claim 1 wherein said second layer compr

Assignees

• Sensel Inc

Inventors

• Rosenberg Ilya Daniel
• Zarraga John Aaron

Classifications

• G06F2203/04103

  Manufacturing, i.e. details related to manufacturing processes specially suited for touch sensitive devices · CPC title

• G06F2203/04106

  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 title

• G06F2203/04104

  Multi-touch detection in digitiser, i.e. details about the simultaneous detection of a plurality of touching locations, e.g. multiple fingers or pen and finger · CPC title

• G06F3/044

  by capacitive means · CPC title

• G06F3/045

  using resistive elements, e.g. a single continuous surface or two parallel surfaces put in contact · CPC title