ESD DETECTION ON A TOUCH INPUT DEVICE

• US 20150309608A1
• Filed: 06/11/2015
• Published: 10/29/2015
• Est. Priority Date: 09/10/2012
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: BENBASAT, Ari Y., WESTERMAN, Wayne Carl, SHIH, David H. C., LIN, Albert, O'CONNOR, Sean E.
• Granted Patent: US 10,203,783 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G06F 3/041 Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means
• CPC Class Codes: G06F 3/04182 Filtering of noise external to the device and not generated by digitiser components
• CPC Class Codes: G06F 3/0425 using a single imaging device like a video camera for tracking the absolute position of a single or a plurality of objects with respect to an imaged reference surface, e.g. video camera imaging a display or a projection screen, a table or a wall surface, on which a computer generated image is displayed or projected tracking a projected light spot to determine a position on a display surface G06F3/0386
• 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 touch sensitive device that detects the occurrence of an electrostatic discharge event on the device by analyzing an acquired touch image for characteristics associated with the occurrence of an ESD event is provided. An acquired touch image is analyzed for characteristics that differentiate it from a touch image generated by a user input and are correlated with an expected touch image generated by an ESD event.

Claims

1. A method for detecting an occurrence of an ESD event on a touch input device, the method comprising:

applying stimulation signals to a plurality of drive lines of a touch sensor panel;

acquiring a touch image of the touch sensor panel wherein the touch image comprises a plurality of sensed values based on the stimulation signals, the sensed values including an ESD value corresponding to and ESD event and touch values corresponding to one or more touch events;

differentiating the ESD event from the touch events by determining if a magnitude of the EDS values exceeds a predetermined threshold, wherein touch events have touch values lower than the predetermined threshold.

2. The method of claim 1, further comprising removing capacitive shielding from the touch input device to permit more energy from the ESD event to be coupled to the touch input device.

3. A method for detecting an occurrence of an ESD event on a touch input device, the method comprising:

applying stimulation signals to a plurality of drive lines of a touch sensor panel;

acquiring a touch image of the touch sensor panel wherein the touch image comprises a plurality of sensed values based on the stimulation signals, the sensed values including an ESD value corresponding to and ESD event and touch values corresponding to one or more touch events;

differentiating the ESD event from the touch events by determining if a magnitude of the EDS values is lower than a predetermined threshold, wherein touch events have touch values higher than the predetermined threshold.

4. The method of claim 3, further comprising applying capacitive shielding to the touch input device to permit less energy from the ESD event to be coupled to the touch input device.

5. A touch sensitive device capable of detecting the occurrence of an ESD event, the device comprising:

a touch sensor panel capable of applying stimulation signals to a plurality of drive lines of the touch sensor panel,

a processor capable of

acquiring a touch image of the touch sensor panel, wherein the touch image comprises a plurality of sensed values based on the stimulation signals, the sensed values including an ESD value corresponding to and ESD event and touch values corresponding to one or more touch events; and

differentiating the ESD event from the touch events by determining if a magnitude of the EDS values exceeds a predetermined threshold, wherein touch events have touch values lower than the predetermined threshold.

6. A touch sensitive device capable of detecting the occurrence of an ESD event, the device comprising:

a touch sensor panel capable of applying stimulation signals to a plurality of drive lines of the touch sensor panel,

a processor capable of

acquiring a touch image of the touch sensor panel, wherein the touch image comprises a plurality of sensed values based on the stimulation signals, the sensed values including an ESD value corresponding to and ESD event and touch values corresponding to one or more touch events; and

differentiating the ESD event from the touch events by determining if a magnitude of the EDS values is lower than a predetermined threshold, wherein touch events have touch values higher than the predetermined threshold.

7. A method for detecting an occurrence of an ESD event on a touch input device, the method comprising:

configuring a specific feature of the touch input device that correspond to selected drive lines among a plurality of drive lines on the touch input device;

applying stimulation signals to the plurality of drive lines of a touch sensor panel;

acquiring a touch image of the touch sensor panel wherein the touch image comprises a plurality of sensed values based on the stimulation signals, the sensed values including an ESD value corresponding to and ESD event and touch values corresponding to one or more touch events; and

differentiating the ESD event from the touch events by determining if the sensed values occur only on the selected drive lines.

8. The method of claim 7 wherein the specific feature establishes a sense signal pathway to sensor circuitry of the touch input device.

9. The method of claim 7, wherein the specific feature comprises bondpads corresponding to the selected drive lines.

10. The method of claim 9, wherein the plurality of drive lines form rows and the selected drive lines comprise every other row of drive lines.

11. A touch sensitive device capable of detecting the occurrence of an ESD event, the device comprising:

a touch sensor panel capable of applying stimulation signals to a plurality of drive lines of the touch sensor panel,

a processor capable of

acquiring a touch image of the touch sensor panel, wherein the touch image comprises a plurality of sensed values based on the stimulation signals, the sensed values including an ESD value corresponding to and ESD event and touch values corresponding to one or more touch events; and

differentiating the ESD event from the touch events by determining if the sensed values occur only on the selected drive lines.

12. The touch sensitive device of claim 11, wherein the specific feature establishes a sense signal pathway to sensor circuitry of the touch input device

13. The touch sensitive device of claim 11, wherein the specific feature comprises bondpads corresponding to the selected drive lines.

14. The touch sensitive device of claim 13, wherein the plurality of drive lines form rows and the selected drive lines comprise every other row of drive lines.