INPUT DEVICE WITH CAPACITIVE FORCE SENSOR AND METHOD FOR CONSTRUCTING THE SAME

• US 20100253645A1
• Filed: 04/03/2009
• Published: 10/07/2010
• Est. Priority Date: 04/03/2009
• Status: Active Grant

• Current Assignee: Synaptics Incorporated
• Original Assignee: Synaptics Incorporated
• Inventors: Bolender, Robert J.
• Granted Patent: US 9,024,907 B2
• Time in Patent Office: Days
• US Class Current: 345/174
• CPC Class Codes: G06F 2203/04105 Pressure sensors for measuring the pressure or force exerted on the touch surface without providing the touch position
• CPC Class Codes: G06F 3/0418 for error correction or compensation, e.g. based on parallax, calibration or alignment
• CPC Class Codes: G06F 3/0447 Position sensing using the local deformation of sensor cells

Abstract

Input devices which include a capacitive force sensor, along with methods of making and using such, are provided. The input device includes a structural component having first and second substantially opposing sides, a plurality of sensor electrodes located on the first side of the structural component, the plurality of sensor electrodes configured to capacitively sense positional information associated with user input in a sensing region, a first capacitive electrode located on the second side of the structural component, the first capacitive electrode being configured to capacitively couple to a second capacitive electrode that is separated from the first capacitive electrode by a gas and moveable relative to the first capacitive electrode, and a biasing member configured to be physically coupled to the structural component such that a force associated with the user input causes a change in a separation distance between the first and second capacitive electrodes based on the force.

Claims

1. An input device comprising:

a structural component having first and second substantially opposing sides;

a plurality of sensor electrodes located on the first side of the structural component, the plurality of sensor electrodes configured to capacitively sense positional information associated with user input in a sensing region;

a first capacitive electrode located on the second side of the structural component, the first capacitive electrode being configured to capacitively couple to a second capacitive electrode that is separated from the first capacitive electrode by a gas and moveable relative to the first capacitive electrode; and

a biasing member configured to be physically coupled to the structural component such that a force associated with the user input causes a change in a separation distance between the first and second capacitive electrodes based on the force.

2. The input device of claim 1, wherein the gas is air.

3. The input device of claim 1, further comprising a casing, wherein at least one of the first capacitive electrode and the second capacitive electrode is attached to the casing.

4. The input device of claim 1, further comprising a casing, wherein the biasing member is formed as part of the casing.

5. The input device of claim 1, wherein the biasing member comprises an elastomeric material, a metallic material, a polymeric material, or a combination thereof.

6. The input device of claim 1, wherein the biasing member is configured to provide a monotonic force-displacement response.

7. The input device of claim 1, further comprising a second biasing member configured to be physically coupled to the structural component, the second biasing member being configured to transmit the force associated with the user input and define the change in the separation distance between the first and second capacitive electrodes based on the force.

8. The input device of claim 1, further comprising one or more additional first capacitive electrodes located on the second side of the structural component, the one or more additional first capacitive electrodes being configured to capacitively couple to the second capacitive electrode.

9. The input device of claim 1, further comprising one or more additional first capacitive electrodes located on the second side of the structural component, the one or more additional first capacitive electrodes being configured to capacitively couple to one or more additional second capacitive electrodes, the one or more additional second capacitive electrodes being moveable relative to the one or more additional first capacitive electrode and separated from the one or more additional first capacitive electrodes by the gas.

10. A touch screen interface for an electronic device, the touch screen interface comprising:

a display screen having a viewing side and a non-viewing side; and

a sensing system proximate to the display screen, the sensing system comprising;

a plurality of sensor electrodes located on the viewing side of the display screen, the plurality of sensor electrodes configured to capacitively sense positional information associated with user input in a sensing region that at least partially overlaps the viewing side of the display screen;

a first capacitive electrode physically coupled to the non-viewing side of the display screen;

a second capacitive electrode spaced from the non-viewing side of the display screen and at least partially overlapping the first capacitive electrode, the second capacitive electrode being moveable relative to the first capacitive electrode and separated from the first capacitive electrode by a gas, wherein the second capacitive electrode is configured to capacitively couple to the first capacitive electrode; and

a biasing member configured to regulate a separation distance between the first and second capacitive electrodes such that a force associated with the user input and applied to the display screen causes the separation distance between the first and second capacitive electrodes to change based on the force.

11. The touch screen interface for an electronic device of claim 10, further comprising a processor in operable communication with the sensing system, the processor being configured to:

capacitively detect the change in the separation distance between the first and second capacitive electrodes; and

determine the force associated with the user input and applied to the display screen based on the change in the separation distance.

12. The touch screen interface for an electronic device of claim 11, wherein the processor is further configured to determine the positional information associated with the user input.

13. The touch screen interface for an electronic device of claim 12, wherein the processor is configured to determine the force associated with the user input and applied to the display screen based on the change in the separation distance by:

estimating the force using the change in the separation distance and the positional information associated with the user input.

14. The touch screen interface of claim 10, further comprising a casing coupled to the display screen, wherein at least one of the second capacitive electrode and the biasing member is attached to the casing.

15. The touch screen interface of claim 14, wherein the at least one of the second capacitive electrode and the biasing member is formed as part of the casing.

16. The touch screen interface of claim 10, further comprising a circuit assembly physically coupled to the display screen, the circuit assembly having a flexible portion configured to bend around the display screen, wherein the plurality of sensor electrodes and the first capacitive electrode are on the circuit assembly.

17. The touch screen interface of claim 10, wherein the biasing member is configured to have a monotonic force-displacement characteristic.

18. The touch screen interface of claim 10, further comprising at least one other biasing member physically coupled to the display screen, the biasing member and the at least one other biasing member configured to provide a monotonic force-displacement response to force applied to the display screen.

19. The touch screen interface of claim 10, further comprising:

one or more additional first capacitive electrodes located on the non-viewing side of the display screen, the one or more additional first capacitive electrodes being configured to capacitively couple to the second capacitive electrode.

20. The touch screen interface of claim 10, further comprising:

one or more additional second capacitive electrodes spaced from the non-viewing side of the display screen, the one or more additional second capacitive electrodes being separated from the first capacitive electrodes by the gas and being moveable relative to the first capacitive electrodes, wherein the one or more additional second capacitive electrodes are configured to capacitively couple to the first capacitive electrodes.

21. The touch screen interface of claim 10, further comprising:

one or more additional first capacitive electrodes located on the non-viewing side of the display screen; and

one or more additional second capacitive electrodes spaced from the non-viewing side of the display screen, the one or more additional second capacitive electrodes being separated from the one or more additional first capacitive electrodes by the gas and being moveable relative to the one or more additional first capacitive electrodes, wherein the one or more additional second capacitive electrodes are configured to capacitively couple to the one or more additional first capacitive electrodes.

22. The touch screen interface of claim 10, further comprising a tension-carrying feature configured to carry a predominant portion of tension applied to the display screen.

23. A method for constructing an input device comprising:

providing a circuit assembly having a flexible portion, the circuit assembly configured to physically couple to a structural component having first and second substantially opposing sides, the circuit assembly being further configured to bend around the structural component at the flexible portion thereof such that a first part of the circuit assembly at least partially overlaps the first side of the structural component and a second part of the circuit assembly at least partially overlaps the second side of the structural component;

disposing a plurality of sensor electrodes on the first part of the circuit assembly, the plurality of sensor electrodes being configured to capacitively sense positional information associated with user input in a sensing region; and

disposing a first capacitive electrode on the second part of the circuit assembly, the first capacitive electrode being configured to capacitively couple to a second capacitive electrode that is separated from the first capacitive electrode by a gas and moveable relative to the first capacitive electrode, wherein a separation distance between the first capacitive electrode and the second capacitive electrode is configured to be regulated by a biasing member configured to be physically coupled to the structural component such that a force associated with the user input causes a repeatable change in the separation distance between the first and second capacitive electrodes based on the force.

24. The method of claim 23, further comprising:

providing the structural component;

providing a display device assembly, the display device assembly comprising;

a casing; and

a display device moveable relative to the casing; and

physically coupling the second part of the circuit assembly to at least one of the display device and the casing.

25. The method of claim 23, further comprising:

providing the structural component; and

providing a casing comprising the second capacitive electrode.