ESD detection on a touch input device

• US 10,203,783 B2
• Filed: 06/11/2015
• Issued: 02/12/2019
• Est. Priority Date: 09/10/2012
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Shih, David H. C., Lin, Albert, O'Connor, Sean E., Benbasat, Ari Y., Westerman, Wayne Carl
• Primary Examiner(s): Giesy, Adam R.
• Application Number:
  US14/737,395
• Publication Number:
  US 20150309608A1
• Time in Patent Office: 1,342 Days
• Field of Search: 324679
• 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 plurality of sensed values including at least one of an ESD value corresponding to an ESD event and one or more touch values corresponding to one or more touch or proximity events;

for each of the plurality of sensed values in the touch image, categorizing the sensed value as being an ESD event when the sensed value is greater than a pre-determined threshold and categorizing the sensed value as being one or more touch events when the sensed value does not exceed the pre-determined threshold; and

when the sensed value is categorized as being an ESD event, ignoring the touch or proximity event acquired during the occurrence of the ESD event.

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 plurality of sensed values including at least one of an ESD value corresponding to an ESD event and one or more touch values corresponding to one or more touch or proximity events;

for each of the plurality of sensed value in the touch image, categorizing the sensed value as being an ESD event when the sensed value is less than a pre-determined threshold and categorizing the sensed value as being one or more touch events when the sensed value is not less than the pre-determined threshold; and

when the sensed value is categorized as being an ESD event, ignoring the touch or proximity event acquired during the occurrence of the ESD event.

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, and

a processor configured for;

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 plurality of sensed values including at least one of an ESD value corresponding to an ESD event and one or more touch values corresponding to one or more touch or proximity events;

for each of the plurality of sensed values in the touch image, categorizing the sensed value as being an ESD event when the sensed value is greater than a pre-determined threshold and categorizing the sensed value as being one or more touch events when the sensed value does not exceed the pre-determined threshold; and

when the sensed value is categorized as being an ESD event, ignoring the touch or proximity event acquired during the occurrence of the ESD event.

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, and

a processor configured for;

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 plurality of sensed values including at least one of an ESD value corresponding to an ESD event and one or more touch values corresponding to one or more touch or proximity events;

for each of the plurality of sensed value in the touch image, categorizing the sensed value as being an ESD event when the sensed value is less than a pre-determined threshold and categorizing the sensed value as being one or more touch events when the sensed value is not less than the pre-determined threshold; and

when the sensed value is categorized as being an ESD event, ignoring the touch or proximity event acquired during the occurrence of the ESD event.

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

applying stimulation signals to the plurality of drive lines of a touch sensor panel wherein a first group of the plurality of drive lines has a specific feature and a second group of drive lines does not have the specific feature;

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 plurality of sensed values including at least one of an ESD value corresponding to an ESD event and one or more touch values corresponding to one or more touch or proximity events;

differentiating the ESD event from the touch events by determining when the sensed values occur only on the first group of drive lines; and

ignoring the touch or proximity event acquired during the occurrence of the ESD event.

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 first group of drive lines.

10. The method of claim 9, wherein the plurality of drive lines form rows and the first group of 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 wherein a first group of the plurality of drive lines includes specific structures separate from the plurality of drive lines and a second group of drive lines does not have the specific structures, and

a processor configured for;

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 plurality of sensed values including at least one of an ESD value corresponding to an ESD event and one or more touch values corresponding to one or more touch or proximity events;

differentiating the ESD event from the touch events by determining when the sensed values originate only from the first group of drive lines; and

ignoring the touch or proximity event acquired during the occurrence of the ESD event.

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

13. The touch sensitive device of claim 11, wherein the specific structures comprise bondpads corresponding to the first group of drive lines.

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