SYSTEM AND METHODS FOR DETERMINING OBJECT INFORMATION USING SELECTIVELY FLOATED ELECTRODES

• US 20130257784A1
• Filed: 03/29/2012
• Published: 10/03/2013
• Est. Priority Date: 03/29/2012
• Status: Active Grant

• Current Assignee: Synaptics Incorporated
• Original Assignee: Synaptics Incorporated
• Inventors: Vandermeijden, Tom R., Small, Jeffrey A.
• Granted Patent: US 9,665,214 B2
• Time in Patent Office: Days
• US Class Current: 345/174
• 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 3/0447 Position sensing using the local deformation of sensor cells

Abstract

The embodiments described herein provide devices and methods that facilitate improved sensor devices. In one embodiment, a capacitive input device is provided that includes a processing system, a plurality of sensing electrodes configured to sense objects in a sensing region, a conductor, and a shield layer comprising at least one shield electrode, where the at least one shield electrode is disposed between the plurality of sensing electrodes and the conductor. The processing system is configured to operate in a first mode and a second mode. When operating in the first mode the processing system is configured to determine position information for objects in the sensing region using the plurality of sensing electrodes. When operating in a second mode the processing system is configured to electrically float the at least one shield electrode and to determine force information for objects in the sensing region using the plurality of sensing electrodes.

Claims

1. A capacitive input device comprising:

a plurality of sensing electrodes configured to sense objects in a sensing region;

a conductor;

a shield layer comprising at least one shield electrode, the at least one shield electrode disposed between the plurality of sensing electrodes and the conductor;

a processing system coupled to the plurality of sensing electrodes and the at least one shield electrode, the processing system configured to;

operate in a first mode, wherein when operating in the first mode the processing system is configured to determine position information for objects in the sensing region using the plurality of sensing electrodes; and

operate in a second mode, wherein when operating in the second mode the processing system is configured to electrically float the at least one shield electrode and to determine force information for objects in the sensing region using the plurality of sensing electrodes.

2. The capacitive input device of claim 1 wherein when operating in the first mode:

the processing system is further configured to electrically drive the at least one shield electrode.

3. The capacitive input device of claim 1 wherein the processing system is configured to determine the force information for objects in the sensing region by determining a deflection response in resulting signals obtained using the plurality of sensing electrodes.

4. The capacitive input device of claim 1 wherein the processing system is further configured to operate in a third mode, wherein when operating in the third mode the processing system is configured to determine the force information for objects in the sensing region using resulting signals obtained using the at least one shield electrode.

5. The capacitive input device of claim 1 wherein the processing system is further configured to switch operation between the first mode and the second mode based at least in part on a determination of input object presence in the sensing region.

6. The capacitive input device of claim 1 wherein the processing system is further configured to switch operation between the first mode and the second mode based at least in part on a determination of noise in resulting signals obtained using the plurality of sensing electrodes.

7. The capacitive input device of claim 1 wherein the at least one shield electrode comprises a plurality of shield electrodes, wherein each of the plurality of shield electrodes are coupled to the processing system, wherein the processing system is configured to electrically float the at least one shield electrode by electrically selectively electrically floating at least one of the plurality of shield electrodes.

8. The capacitive input device of claim 1 further comprising a spacing layer disposed between the shield layer and the conductor, wherein the capacitive input device is configured such that a force applied by an input object to an input surface of the capacitive input device causes a deflection of the plurality of sensing electrodes and the shield layer relative to the conductor.

9. A sensor device comprising:

an input surface;

a plurality of transmitter electrodes and a plurality of receiver electrodes proximate to the input surface, the plurality of transmitter electrodes and the plurality of receiver electrodes configured to capacitively sense objects in a sensing region;

a shield layer comprising at least one shield electrode, the at least one shield electrode disposed proximate the plurality of transmitter electrodes and the plurality of receiver electrodes;

a display disposed proximate the shield layer, wherein the plurality of transmitter electrodes, the receiver electrodes, and the shield layer are configured to deflect toward the display in response to force applied by an input object to the input surface; and

a processing system coupled to the plurality of transmitter electrodes, the plurality of receiver electrodes, and the at least one shield electrode, the processing system configured to;

selectively operate in a first mode, wherein when operating in the first mode the processing system electrically drives the at least one shield electrode to an electrical potential while driving the plurality of transmitter electrodes and receiving first type resulting signals using the plurality of receiver electrodes;

selectively operate in a second mode, wherein when operating in the second mode the processing system electrically floats the at least one shield electrode while driving the plurality of transmitter electrodes, and receiving second type resulting signal using the plurality of receiver electrodes;

determine positional information for objects in the sensing region using at least the first type resulting signals; and

determine force information for objects in the sensing region using at least the second type resulting signals.

10. A processing system for a capacitive input device comprising:

a sensor module comprising sensor circuitry, the sensor module configured to;

selectively operate in a first mode and a second mode;

wherein;

while operating in the first mode, the sensor module is configured to drive a plurality of sensing electrodes configured to sense objects in a sensing region while driving a shield layer to generate resulting signals of a first type indicative of objects in the sensing region;

while operating in the second mode, the sensor module is configured to drive the plurality of sensing electrodes configured to sense objects in the sensing region while floating the shield layer to generate resulting signals of a second type indicative of objects in the sensing region;

a determination module configured to;

determine positional information for objects in the sensing region using at least one of the resulting signals of the first type and the resulting signals of the second type; and

determine force information for objects in the sensing region using at least the resulting signals of the second type.

11. The processing system of claim 10 wherein the determination module is configured to determine the force information for objects in the sensing region by determining a deflection response in the resulting signals of the second type.

12. The processing system of claim 10 wherein the sensor module is further configured to operate in a third mode, and while operating in the third mode the sensor module is configured to generate resulting signals of a third type, indicative of objects in the sensing region using signals from at least one shield electrode in the shield layer.

13. The processing system of claim 10 wherein the sensor module is further configured to switch operation between the first mode and the second mode based at least in part on a determination of input object presence in the sensing region.

14. The processing system of claim 10 wherein the sensor module is further configured to switch operation between the first mode and the second mode based at least in part on a determination of noise in at least one of the resulting signals of the second type.

15. The processing system of claim 10 wherein the shield layer comprises a plurality of shield electrodes, and wherein floating the shield layer while operating in the second mode comprises floating at least one of a plurality of shield electrodes in the shield layer.

16. A method for determining input information in a sensing region of a capacitive input device comprising:

driving a plurality of sensing electrodes configured to sense objects in the sensing region while driving a shield layer to generate resulting signals of a first type indicative of objects in the sensing region;

driving the plurality of sensing electrodes configured to sense objects in the sensing region while floating the shield layer to generate resulting signals of a second type indicative of objects in the sensing region;

determining positional information for objects in the sensing region using at least one of the resulting signals of the first type and the resulting signals of the second type; and

determining force information for objects in the sensing region using at least the resulting signals of the second type.

17. The method of claim 16 wherein the force information for objects in the sensing region is determined from a deflection response in the resulting signals of the second type.

18. The method of claim 16 further comprises selectively determining the positional information and the force information based on a determination of input object presence in the sensing region.

19. The method of claim 16 wherein the shield layer comprises a plurality of shield electrodes, and wherein floating the shield layer comprises selectively floating at least one of the plurality of shield electrodes in the shield layer.

20. The method of claim 16 further comprising switching between the driving the shield layer to floating the shield layer based at least in part on a determination of input object presence in the sensing region.