ESD detection on a touch input device

Patent metadata

Field	Value
Publication number	US-10203783-B2
Application number	US-201514737395-A
Country	US
Kind code	B2
Filing date	Jun 11, 2015
Priority date	Sep 10, 2012
Publication date	Feb 12, 2019
Grant date	Feb 12, 2019

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.

First claim

What is claimed is:

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.

Assignees

• Apple Inc

Inventors

• Shih David H C
• Lin Albert
• O'Connor Sean E
• Benbasat Ari Y
• Westerman Wayne Carl

Classifications

• G06F3/0425

  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 title

• G06F3/044

  by capacitive means · CPC title

• G06F3/041 Primary

  Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means · CPC title

• G06F3/0446 Primary

  using a grid-like structure of electrodes in at least two directions, e.g. using row and column electrodes · CPC title

• G06F3/04182

  Filtering of noise external to the device and not generated by digitiser components · CPC title