Matrix sensor for image touch sensing

• US 8,970,537 B1
• Filed: 01/17/2014
• Issued: 03/03/2015
• Est. Priority Date: 09/30/2013
• Status: Expired due to Fees

• Current Assignee: Synaptics Incorporated
• Original Assignee: Synaptics Incorporated
• Inventors: Shepelev, Petr, Ludden, Christopher A., Lukanc, Jeffrey, Morein, Stephen L., Reynolds, Joseph Kurth, Semeraro, Greg P.
• Primary Examiner(s): Pervan, Michael
• Application Number:
  US14/158,254
• Time in Patent Office: 410 Days
• Field of Search: 178 1801- 1907, 345173-178
• US Class Current: 345/173
• CPC Class Codes: G06F 2203/04101 2.5D-digitiser, i.e. digitiser detecting the X/Y position of the input means, finger or stylus, also when it does not touch, but is proximate to the digitiser's interaction surface and also measures the distance of the input means within a short range in the Z direction, possibly with a separate measurement setup
• 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 2203/04106 Multi-sensing digitiser, i.e. digitiser using at least two different sensing technologies simultaneously or alternatively, e.g. for detecting pen and finger, for saving power or for improving position detection
• CPC Class Codes: G06F 2203/04107 Shielding in digitiser, i.e. guard or shielding arrangements, mostly for capacitive touchscreens, e.g. driven shields, driven grounds
• CPC Class Codes: G06F 2203/04111 Cross over in capacitive digitiser, i.e. details of structures for connecting electrodes of the sensing pattern where the connections cross each other, e.g. bridge structures comprising an insulating layer, or vias through substrate
• CPC Class Codes: G06F 2203/04112 Electrode mesh in capacitive digitiser: electrode for touch sensing is formed of a mesh of very fine, normally metallic, interconnected lines that are almost invisible to see. This provides a quite large but transparent electrode surface, without need for ITO or similar transparent conductive material
• CPC Class Codes: G06F 3/0412 Digitisers structurally integrated in a display
• CPC Class Codes: G06F 3/041662 using alternate mutual and self-capacitive scanning
• CPC Class Codes: G06F 3/04184 Synchronisation with the driving of the display or the backlighting unit to avoid interferences generated internally
• CPC Class Codes: G06F 3/0443 using a single layer of sensing electrodes
• CPC Class Codes: G06F 3/0445 using two or more layers of sensing electrodes, e.g. using two layers of electrodes separated by a dielectric layer
• CPC Class Codes: G06F 3/0448 Details of the electrode shape, e.g. for enhancing the detection of touches, for generating specific electric field shapes, for enhancing display quality

Abstract

Embodiments described herein include a display device having a capacitive sensing device, a processing system and a method for detecting presence of an input object using a capacitive sensing device, all of which include a grid electrode for improved absolute sensing. Other embodiments include a display device having a capacitive sensing device, a processing system and a method for detecting presence of an input object using a capacitive sensing device, wherein the capacitive sensing device includes a matrix of discrete sensor electrodes.

Claims

1. A display device having an integrated capacitive sensing device, the display device comprising:

a plurality of sensor electrodes, wherein each sensor electrode comprises at least one common electrode configured to be driven for display updating and capacitive sensing;

a grid electrode disposed between and separating a first sensor electrode and a second sensor electrode of the plurality of sensor electrodes, the first sensor electrode and the second sensor electrode separately circumscribed by the grid electrode, the grid electrode configured to shield the first sensor electrode and the second sensor electrode; and

a processing system coupled to the sensor electrodes and the grid electrode, the processing system is configured to, in a first processing mode, modulate the first sensor electrode and the second sensor electrode to acquire measurements of changes in absolute capacitance indicative of positional information for an input object in a sensing region of the capacitive sensing device based on the measurements.

2. The display device of claim 1, wherein the grid electrode comprises at least one common electrode.

3. The display device of claim 1, wherein the grid electrode is laterally spaced apart from the two sensor electrodes a distance corresponding to dimensions of the pixel elements.

4. The display device of claim 1, wherein the grid electrode overlaps the first sensor electrode and the second sensor electrode.

5. The display device of claim 1, wherein in the first processing mode an electrically floating common electrode is positioned between the first sensor electrode and the grid electrode.

6. The display device of claim 1, wherein the grid electrode is coplanar with the sensor electrodes.

7. The display device of claim 1, wherein the grid electrode is oriented in a plane parallel to a plane of the sensor electrodes.

8. The display device of claim 1, wherein the grid electrode is disposed between the plurality of sensor electrodes and a lens of the display device.

9. The display device of claim 1, wherein the grid electrode comprises a wire mesh.

10. The display device of claim 1, wherein the grid electrode of the capacitive sensing device is disposed on a color filter glass of the display device.

11. The display device of claim 1, wherein the grid electrode of the capacitive sensing device is aligned with a black mask of the display device.

12. The display device of claim 1, wherein the grid electrode comprises:

a plurality of segments which may be independently driven by the processing system.

13. The display device of claim 1, wherein modulating the first sensor electrode and the second sensor electrode comprises driving the first sensor electrode and the second sensor electrode with a modulated signal wherein the processing system is further configured to drive the grid electrode with a shielding signal that is similar in at least one of phase and amplitude to the modulated signal.

14. The display device of claim 1, wherein the processing system is further configured to drive the grid electrode with a shielding signal having a substantially constant voltage.

15. The display device of claim 1, wherein the processing system is configured to drive a transmitter signal onto the grid electrode and configured to receive from the plurality of sensor electrodes resulting signals comprising effects corresponding to the transmitter signal.

16. The display device of claim 1, wherein the sensor electrodes have a geometric shape substantially circumscribed by the grid electrode.

17. The display device of claim 1, wherein the first sensor electrode and the second sensor electrode, when operated in the first processing mode, are shielded by the grid electrode over a capacitive frame.

18. A processing system for an input device, the processing system comprising;

a sensor module, comprising sensor circuitry coupled to a grid electrode disposed between and separating a first sensor electrode and a second sensor electrode of a plurality of sensor electrodes, the first sensor electrode and the second sensor electrode separately circumscribed by the grid electrode, wherein each of the plurality of sensor electrodes comprises at least one common electrode configured to be driven for display updating and capacitive sensing, the sensor module configured to;

in a first mode of operation, modulate the first sensor electrode and the second sensor electrode to acquire measurements of changes in absolute capacitance between the first sensor electrode, the second sensor electrode and an input object and drive the grid electrode with a shielding signal configured to shield the first sensor electrode and the second sensor electrode.

19. The processing system of claim 18 further comprising a detection module configured to determine positional information for the input object based on the measurements of changes in absolute capacitance.

20. The processing system of claim 18, wherein the processing module is configured to, in a second mode of operation, drive a transmitter signal onto the grid electrode and configured to receive from the plurality of sensor electrodes resulting signals comprising effects corresponding to the transmitter signal.

21. The processing system of claim 18, wherein the processing module is configured to, in a second mode of operation, at least one of couple the grid electrode to a substantially constant voltage and electrically float the grid electrode;

and

wherein the processing module is configured to, in the second mode of operation, drive a transmitter signal onto the first sensor electrode of the plurality of sensor electrode and receive from the second sensor electrode of the plurality of sensor electrodes resulting signals comprising effects corresponding to the transmitter signal.

22. The processing system of claim 18, wherein the grid electrodes comprises at least one common electrode of a display device.

23. The processing system of claim 18, wherein the grid electrode is disposed between an active layer and a lens of the display device.

24. The processing system of claim 18, wherein the sensor module is configured to, in a second mode of operation, drive a second shielding signal onto the grid electrode, wherein the first shielding signal and the second shielding signal comprise varying voltage waveforms and wherein the varying voltage waveform of the first shielding signal comprises a higher amplitude than the varying voltage waveform of the second shielding signal.

25. The processing system of claim 18, wherein the sensor module is configured to, in a second mode of operation, drive a second shielding signal onto the grid electrode wherein one of the first shielding signals and the second shielding signals comprises a substantially constant voltage.

26. The processing system of claim 18, wherein the first sensor electrode and the second sensor electrode, when operated in the first processing mode, are shielded by the grid electrode over a capacitive frame.

27. A method for detecting presence of an input object using a capacitive sensing device, the capacitive sensing device having a grid electrode disposed between and separating a first sensor electrode and a second sensor electrode of a plurality of sensor electrodes, the first sensor electrode and the second sensor electrode separately circumscribed by the grid electrode, wherein each of the plurality of sensor electrodes comprises at least one common electrodes of a display device, the method comprising:

acquiring measurements of changes in absolute capacitive sensing by driving onto and receiving with the first sensor electrode while in a first mode of operation;

driving the grid electrode with a shielding signal while in the first mode of operation, the shielding signal to shield the first sensor electrode and the second sensor electrode; and

determining positional information based on the measurements of changes in absolute capacitive coupling.

28. The method of claim 27, wherein the grid electrode comprises at least one common electrode of the display device.

29. The method of claim 27, wherein driving onto and receiving with the first sensor electrode comprises driving the first sensor electrode with a modulated signal, and wherein the shielding signal and the modulated signal are substantially similar in at least one of amplitude and phase.

30. The method of claim 27 further comprising driving a transmitter signal onto the grid electrode and configured to receive from the plurality of sensor electrodes resulting signals comprising effects corresponding to the transmitter signal.

31. The method of claim 27, wherein driving the grid electrode with a shielding signal while in the first mode of operation shields the first sensor electrode and the second sensor electrode for a capacitive frame.