Touch panel system and method for distinguishing multiple touch inputs

• US 7,254,775 B2
• Filed: 10/03/2001
• Issued: 08/07/2007
• Est. Priority Date: 10/03/2001
• Status: Expired due to Fees

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Hagermoser, Edward S., Schulz, Stephen C., Cordeiro, Craig A., Taylor, Gordon F., Moshrefzadeh, Robert S., Peterson, Richard A. Jr., Hauck, Karl P., Geaghan, Bernard O., Hatin, Paul M., Hart, James J.
• Primary Examiner(s): Kincaid; Kristine
• Assistant Examiner(s): Ke; Peng
• Application Number:
  US09/970,474
• Publication Number:
  US 20030063073A1
• Time in Patent Office: 2,134 Days
• Field of Search: 715/701, 715/702, 715/863, 715/856, 715/857, 715/858, 715/859, 715/860, 715/861, 715/862, 345/173, 345/179, 178/18.01
• US Class Current: 715/701
• CPC Class Codes: G06F 2203/04104 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 Class Codes: G06F 3/0416 Control or interface arrangements specially adapted for digitisers
• CPC Class Codes: G06F 3/0488 using a touch-screen or digitiser, e.g. input of commands through traced gestures

Abstract

Touch panel systems and methods are disclosed that can distinguish temporally overlapping touch inputs from single touch inputs so that valid touch position coordinates can be determined. Touch panel systems and methods of the present invention can distinguish overlapping touches by comparing signal magnitudes to specified thresholds, by comparing the rates of change of signal magnitudes or measured positions to determined parameters, by locating the proximity a calculated location to icons or other such active areas, and the like. Because touch panel systems and methods of the present invention can discriminate single touches from double touches, they can be used in multiple user applications such as multiplayer games as well as in applications that may be subject to rapidly successive or overlapping touch inputs.

Claims

1. A method for distinguishing between two or more temporally overlapping touch inputs in a touch screen system comprising:

(a) measuring signals caused by the two or more touch inputs;

(b) measuring positional data for the touch inputs;

(c) determining whether any of the signals exceeds a minimum threshold for a single touch input;

(d) determining whether any of the signals exceeds a maximum threshold for a single touch input;

(e) Calculating and reporting to the touch screen system a touch location using positional data that corresponds to any of the signals that exceeds the minimum threshold but that does not exceed the maximum threshold; and

Wherein different minimum and maximum threshold values can be assigned to different users.

2. The method of claim 1, further comprising the step of subtracting the positional data used in step (e) from positional data corresponding to any of the signals that exceeds the maximum threshold to calculate a touch location unreported by step (e).

3. The method of claim 1, further comprising determining which portions of the total signal correspond to touch-down, hold, and lift-off events of the two or more overlapping touch inputs.

4. The method of claim 1, further comprising the step of calculating and reporting a touch location when two sequential performances of steps (a) through (e) both result in no touch location being reported due n the signals exceeding the maximum threshold.

5. The method of claim 1, wherein at least one of the minimum and maximum thresholds are determined from a calibration step.

6. The method of claim 1, wherein the minimum and maximum thresholds comprise preset values.

7. The method of claim 1, wherein at least one of the minimum and maximum thresholds are updated during normal use of the touch screen system.

8. The method of claim 1, wherein at least one of the minimum and maximum thresholds are updated based on user touches within a designated region.

9. The method of claim 1, wherein the total signal is a total electrical current measurement.

10. The method of claim 1, wherein the touch screen system comprises a capacitive touch screen.

11. The method of claim 1, wherein the touch screen system comprises a resistive touch seven.

12. The method of claim 1, wherein the touch screen system comprises a force-based touch screen.

13. The method of claim 1, wherein a touch location is reported in step (e) only if the touch location calculated in step (e) is contained within an area of the touch screen designated as a valid touch area.