In-situ detection of touchscreen panel shorts

• US 8,810,532 B2
• Filed: 04/22/2011
• Issued: 08/19/2014
• Est. Priority Date: 04/22/2011
• Status: Active Grant

• Current Assignee: PixArt Imaging Incorporated
• Original Assignee: PixArt Imaging Incorporated
• Inventors: Narasimhan, Sarangan, Gil, Mercedes E.
• Primary Examiner(s): HARRIS, DOROTHY H
• Application Number:
  US13/092,642
• Publication Number:
  US 20120268413A1
• Time in Patent Office: 1,215 Days
• Field of Search: 345/174
• US Class Current: 345/173
• CPC Class Codes: G06F 2203/04103 Manufacturing, i.e. details related to manufacturing processes specially suited for touch sensitive devices
• CPC Class Codes: G06F 3/0418 for error correction or compensation, e.g. based on parallax, calibration or alignment
• CPC Class Codes: G06F 3/044 by capacitive means
• 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

A test system for testing a capacitive-sense touchscreen is disclosed. Specifically, the test system may be incorporated within a controller that is also used to control operations of the touchscreen. The controller may include an Integrated Circuit and the test system may correspond to a test capacitor embedded into the Integrated Circuit.

Claims

1. A touchscreen controller, comprising:

one or more controlling components configured to control operations of a touchscreen or portions thereof by sensing a user input at the touchscreen and providing one or more outputs to a host processor indicative of the user input; and

one or more testing components configured to test the touchscreen or elements thereof for faults;

wherein the one or more testing components comprise a switch matrix configured to selectively couple and uncouple sense electronics to drive electronics;

wherein the one or more controlling components comprise instructions for detecting changes in measurements obtained from electric signals received at the sense electronics and converting the detected changes to user input data and wherein the one or more testing components comprises a test capacitor integrated within the controller;

wherein the switch matrix is further configured to selectively couple and uncouple the test capacitor to the sense electronics;

wherein the switch matrix is further configured to selectively couple and uncouple the test capacitor to the drive electronics; and

wherein the test capacitor is configured to be connected in parallel between a drive line in the drive electronics and a sense line in the sense electronics when corresponding drive line switches and sense line switches in the switch matrix are closed.

3. The controller of claim 1, wherein the one or more testing components comprises an electrical coupling mechanism and instructions configured to execute a touchscreen testing process by selectively coupling and uncoupling the electrical coupling mechanism to drive lines and sense lines passing through the touchscreen.

4. An Integrated Circuit comprising the controller of claim 1.

2. The controller of claim, wherein the test capacitor comprises a capacitance at least twice as large as a mutual capacitance created between a drive line in the drive electronics and a sense line in the sense electronics when the drive line is driven.

5. An apparatus configured to control a touchscreen by detecting user input at the touchscreen and generating one or more electrical signals indicative of the detected user input, the apparatus comprising:

testing components configured to test a touch-sensitive panel of the touchscreen for faults;

wherein the one or more testing components comprise a switch matrix configured to selectively couple and uncouple sense electronics to drive electronics;

wherein the testing components include the drive electronics electrically connected to drive lines in the touch-sensitive panel;

wherein the testing components further include the sense electronics electrically connected to sense lines in the touch-sensitive panel;

wherein the testing components further include a coupling mechanism connectable to the drive electronics and sense electronics via the switch matrix; and

wherein the coupling mechanism is configured to be connected in parallel between a drive line in the drive electronics and a sense line in the sense electronics when corresponding drive line switches and sense line switches in the switch matrix are closed.

6. The apparatus of claim 5, wherein the switch matrix is configured to individually connect the coupling mechanism between each drive line in the touch-sensitive panel and each sense line in the touch-sensitive panel.

7. The apparatus of claim 5, wherein the testing components further comprise instructions configured to perform a testing process that controls whether the coupling mechanism is connected to a particular drive or sense line by controlling whether a switch in the switch matrix is open or closed.

8. The apparatus of claim 7, further comprising memory which stores the instructions as firmware.

9. A user device comprising the apparatus of claim 5.

10. A method for detecting faults in at least one of a touchscreen and a touch-sensitive panel, comprising:

retrieving instructions from a touchscreen controller to begin a testing process;

connecting test electronics incorporated within the touchscreen controller between at least one of a drive/sense line pair, drive/drive line pair, and sense/sense line pair and selectively coupling and uncoupling sense electronics to the drive electronics via a switch matrix to determine whether a fault exists in the at least one of a touchscreen and touch-sensitive panel;

measuring electrical signal outputs across the test electronics at the touchscreen controller; and

based on the measured electrical signal outputs, determining whether the at least one of a touchscreen and touch-sensitive panel comprises a fault;

wherein the connecting step comprises connecting electrical coupling means in parallel across a first drive line and a first sense line.

11. The method of claim 10, wherein measuring electrical signal outputs comprises determining a first voltage or current reading at a first sense line, determining a second voltage or current reading at a second sense line, and comparing the first and second readings.

12. The method of claim 10, wherein the touchscreen comprises a capacitive-sense touchscreen and wherein the touch-sensitive panel comprises electrically conductive traces of Indium Tin Oxide (ITO) laid down on a substrate.

13. The method of claim 10, further comprising connecting the test electronics across at least one of (i) a plurality of drive lines, (ii) a plurality of sense lines, and (iii) a plurality of drive/sense line pairs.

14. The method of claim 10, further comprising sequentially testing different drive/sense line pairs by sequentially connecting the test electronics across different drive lines and sense lines.