Touch Profiling on Capacitive-Touch Screens

• US 20140028605A1
• Filed: 07/26/2012
• Published: 01/30/2014
• Est. Priority Date: 07/26/2012
• Status: Abandoned Application

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Luo, Chenchi Eric, Borkar, Milind
• Application Number:
  US13/559,118
• Publication Number:
  US 20140028605A1
• Time in Patent Office: Days
• US Class Current: 345/174
• 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

Abstract

An embodiment of the invention provides a method and apparatus for determining what type of interaction is made with a capacitive touch screen. A capacitance sensor with the largest sensed capacitance in a group of capacitance sensors is determined. Next, a parametric surface is determined from the value of the largest sensed capacitance and the values of the sensed capacitances in the group of capacitance sensors. From the parametric surface, an interpolated peak capacitance, a curvature K at the interpolated peak and an orientation θ at the interpolated peak are determined. Based on the interpolated peak capacitance, the curvature K and the orientation θ, the type of interaction made with the capacitive-touch screen is identified.

Claims

1. A machine-implemented method of determining a type of interaction made with capacitive-touch screen comprising:

determining, using an electronic device, the capacitance sensor with the largest sensed capacitance in a group of capacitance sensors, wherein the group of capacitance sensors are located on the capacitive-touch screen;

wherein the capacitive-touch screen is located on an electronic device;

determining a parametric surface from the value of the largest sensed capacitance and the values of the sensed capacitances in the group of capacitance sensors;

determining coordinates (x₀, y₀, z₀) for an interpolated peak capacitance from the parametric surface,

determining a curvature K at the interpolated peak from the parametric surface; and

determining an orientation θ

at the interpolated peak capacitance from the parametric surface;

wherein the type of interaction made with the capacitive-touch screen is determined by the interpolated peak capacitance, the curvature K and the orientation θ

.

2. The method of claim 1 wherein the group of capacitance sensors comprises 9 capacitance sensors wherein the capacitance sensor with the largest sensed capacitance is adjacent to all 8 other capacitance sensors and all 8 other capacitance sensors have smaller sensed capacitances than the capacitance sensor with the largest capacitance.

3. The method of claim 1 wherein the type of interaction made with the capacitive-touch screen is a human palm when the magnitude of the interpolated peak capacitance is relatively low and the curvature K at the interpolated peak is relatively low.

4. The method of claim 1 wherein the type of interaction made with the capacitive-touch screen is a human finger when the magnitude of the interpolated peak capacitance is relatively high and the curvature K at the interpolated peak is relatively moderate.

5. The method of claim 1 wherein the type of interaction made with the capacitive-touch screen is a stylus when the magnitude of the interpolated peak capacitance is relatively high and the curvature K at the interpolated peak is relatively high.

6. The method of claim 1 wherein the parametric surface is defined by the following equation:

f(x,y)=Ax²+Bxy+Cy²+Dx+Ey+F.

7. The method of claim 1 wherein the coordinates (x₀, y₀, z₀) for an interpolated peak capacitance from the parametric surface can be calculated by solving the following equations:

8. The method of claim 1 wherein the curvature K at the peak of the parametric surface is defined by the following equation:

K=4AC−

B².

9. The method of claim 1 wherein the orientation θ

at the peak of the parametric surface is defined by the following equation;

10. The method of claim 1 wherein the electronic device is selected from a group consisting of a cellular phone, a hand-held personal computer, a tablet personal computer, a portable personal computer, a monitor and a television.

11. An electronic device comprising:

a peak finding circuit configured to determine a capacitance sensor with the largest sensed capacitance in a group of capacitance sensors, wherein the group of capacitance sensors are located on a capacitive-touch screen;

wherein the capacitive-touch screen is located on the electronic device;

a conic surface modeling circuit to determine a parametric surface from the value of the largest sensed capacitance and the values of the sensed capacitances in the group of capacitance sensors;

a peak information derivation circuit to determine coordinates (x₀, y₀, z₀) for an interpolated peak capacitance from the parametric surface, a curvature K at the interpolated peak capacitance from the parametric surface and an orientation θ

at the interpolated peak capacitance from the parametric surface;

wherein the type of interaction made with the capacitance-touch screen is determined by the interpolated peak capacitance, the curvature K and the orientation θ

.

12. The electronic device of claim 11 wherein the group of capacitance sensors comprises 9 capacitance sensors wherein the capacitance sensor with the largest sensed capacitance is adjacent to all 8 other capacitance sensors and all 8 other capacitance sensors have smaller sensed capacitances than the capacitance sensor with the largest capacitance.

13. The electronic device of claim 11 wherein the type of interaction made with the capacitive-touch screen is a human palm when the magnitude of the interpolated peak capacitance is relatively low and the curvature K at the interpolated peak is relatively low.

14. The electronic device of claim 11 wherein the type of interaction made with the capacitive touch screen is a human finger when the magnitude of the interpolated peak capacitance is relatively high and the curvature K at the interpolated peak is relatively moderate.

15. The electronic device of claim 11 wherein the type of interaction made with the capacitive touch screen is a stylus when the magnitude of the interpolated peak capacitance is relatively high and the curvature K at the interpolated peak is relatively high.

16. The electronic device of claim 11 wherein the parametric surface is defined by the following equation:

f(x,y)=Ax²+Bxy+Cy²+Dx+Ey+F.

17. The electronic device of claim 11 wherein the coordinates (x₀, y₀, z₀) for an interpolated peak capacitance from the parametric surface can be calculated by solving the following equations:

18. The electronic device of claim 11 wherein the curvature K at the peak of the parametric surface is defined by the following equation:

K=4AC−

B².

19. The electronic device of claim 11 wherein the orientation θ

at the peak of the parametric surface is defined by the following equation;

20. The electronic device of claim 11 wherein the electronic device is selected from a group consisting of a cellular phone, a hand-held personal computer, a tablet personal computer, a portable personal computer, a monitor and a television.

21. The electronic device of claim 11 wherein the peak finding circuit, the conic surface modeling circuit and the peak information derivation circuit are located on the same integrated circuit.