INPUT DEVICE WITH FORCE SENSING

• US 20110278078A1
• Filed: 05/11/2010
• Published: 11/17/2011
• Est. Priority Date: 05/11/2010
• Status: Active Grant

• Current Assignee: Synaptics Incorporated
• Original Assignee: Synaptics Incorporated
• Inventors: Bolender, Robert J., Nordby, Fritz, Day, Shawn P., Schwartz, Adam, Schediwy, Richard R.
• Granted Patent: US 9,057,653 B2
• Time in Patent Office: Days
• US Class Current: 178/18.06
• CPC Class Codes: G01L 1/146 for measuring force distributions, e.g. using force arrays G01L1/148 takes precedence
• 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 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 3/0446 using a grid-like structure of electrodes in at least two directions, e.g. using row and column electrodes
• CPC Class Codes: H03K 17/98 having a plurality of control members, e.g. keyboard

Abstract

Devices and methods are provided that utilize a first electrode disposed on a first substrate and a second electrode disposed on a second substrate, where the first electrode and the second electrode define at least part of a variable capacitance. A third substrate is arranged between the first substrate and the second substrate, the third substrate having an opening arranged such that at least a portion of the first electrode and the second electrode overlap the opening. A transmission element is provided that partially overlaps the opening. The transmission element is physically coupled to the second electrode such that a force biasing the transmission element causes the second electrode to deflect relative to the first electrode, thus changing the variable capacitance. A measurement of the variable capacitance may then be used to determine force information.

Claims

1. An input device comprising:

a first electrode disposed on a first substrate;

a second electrode coupled to a second substrate, the second electrode overlapping the first electrode, wherein the first electrode and the second electrode define at least part of a variable capacitance;

a third substrate having an opening, the third substrate arranged between the first substrate and the second substrate with the opening between at least a portion of the first electrode and at least a portion the second electrode; and

a transmission element physically coupled to the second substrate and configured such that force biasing the transmission element causes the second electrode to deflect relative to the first electrode and changes the variable capacitance.

2. The input device of claim 1 wherein the transmission element is configured to overlap at least a portion of the second electrode and wherein the transmission element is further dimensioned to at least partially overlap the opening.

3. The input device of claim 1 further comprising a processing system communicatively coupled to the first electrode and the second electrode, the processing system configured to determine a capacitance value of the variable capacitance and determine force information using the capacitance value.

4. The input device of claim 1 further comprising a vent, the vent facilitating gas flow when the second electrode is deflected relative to the first electrode.

5. The input device of claim 1 wherein the second substrate comprises polyimide, polyethylene terephthalate, or polycarbonate, and wherein the first substrate comprises a material selected from a group consisting of polyimide, polyethylene terephthalate, polycarbonate, fiberglass, poly(methyl methacrylate), and glass.

6. The input device of claim 1 further comprising a first plurality of capacitive sensor electrodes disposed on at least one of the first substrate, the second substrate, and the third substrate, the first plurality of capacitive sensor electrodes configured to detect objects in a sensing region.

7. The input device of claim 2 further comprising a third electrode capacitively coupled to both the first and second electrodes and communicatively coupled to the processing system, wherein the processing system is configured to determine a capacitance value of the variable capacitance by:

determining a capacitive coupling between at least two of the first, second and third sensor electrodes.

8. An input device comprising:

a first substrate;

a second substrate;

a third substrate arranged between the first substrate and the second substrate, the third substrate including a first opening;

a plurality of capacitive sensor electrodes, the plurality of capacitive sensor electrodes disposed on at least one substrate selected from the group consisting of the first substrate, the second substrate, and the third substrate, the plurality of capacitive sensor electrodes configured to detect objects in a sensing region;

a touch surface configured to be touched by objects in the sensing region;

a first force electrode disposed on the first substrate, the first force electrode at least partially overlapping the first opening in the third substrate;

a second force electrode disposed on the second substrate, the second force electrode at least partially overlapping the first opening in the third substrate, the first and second force electrodes defining at least part of a first variable capacitance; and

a transmission element physically coupled to the second force electrode and configured such that force applied to the touch surface transmits to the transmission element and deflects the second force electrode relative to the first force electrode, changing the first variable capacitance.

9. The input device of claim 8 further comprising a processing system coupled to the plurality of capacitive sensor electrodes, the first force electrode, and the second force electrode, the processing system configured to:

determine positional information for objects in the sensing region;

determine a first capacitance value of the first variable capacitance; and

determine force information for the force applied to the touch surface using the first capacitance value.

10. The input device of claim 8 further comprising a vent in at least one of the first, second and third substrates, the vent facilitating gas flow when the second force electrode is deflected relative to the first force electrode.

11. The input device of claim 8 wherein the transmission element is configured to fit within the first opening.

12. The input device of claim 8 wherein the second substrate comprises polyimide, polyethylene terephthalate, or polycarbonate, and wherein the first substrate comprises a material selected from a group consisting of polyimide, polyethylene terephthalate, polycarbonate, fiberglass, poly(methyl methacrylate), and glass.

13. The input device of claim 9 further comprising a set of routing traces disposed on at least one of the first substrate, the second substrate and the third substrate, the set of routing traces coupled to the plurality of capacitive sensor electrodes and the processing system.

14. The input device of claim 9 wherein the first force electrode is disposed at a first location of the first substrate, the input device further comprising:

a third force electrode disposed on the first substrate at a second location;

a fourth force electrode disposed on the second substrate, the fourth force electrode at least partially overlapping the third force electrode, the third force electrode and the fourth force electrode defining at least part of a second variable capacitance;

a second opening in the third substrate, wherein the second opening overlaps at least a portion of the third force electrode and at least a portion of the fourth force electrode;

a second transmission element, the second transmission element physically coupled to the fourth force electrode and configured such that the force applied to the touch surface transmits to the second transmission element and deflects the fourth force electrode relative to the third force electrode, changing the second variable capacitance; and

wherein the processing system is further configured to determine a second capacitance value of the second variable capacitance and determine the force information for the force applied to the touch surface using the second capacitance value.

15. The input device of claim 9 further comprising:

a third electrode disposed on the first substrate;

a fourth electrode disposed on the second substrate, the third electrode and the fourth electrode defining at least part of a second variable capacitance;

a second opening in the third substrate, wherein the second opening overlaps at least a portion of the third electrode and at least a portion the fourth electrode;

wherein the processing system is further configured to determine a second capacitance value of the second variable capacitance and use the second capacitance value for calibration of the determined force information.

16. An input device comprising:

a first substrate;

a second substrate;

a third substrate arranged between the first substrate and the second substrate, the third substrate including a first opening;

a first plurality of capacitive sensor electrodes disposed on the first substrate;

a second plurality of capacitive sensor electrodes disposed on the third substrate, where the first and second plurality of capacitive sensor electrodes are configured to capacitively detect objects in a sensing region;

a first force electrode disposed on the first substrate, the first force electrode at least partially overlapping the first opening in the third substrate;

a second force electrode disposed on the second substrate, the second force electrode at least partially overlapping the first opening in the third substrate;

wherein the first and second force electrodes define at least part of a first variable capacitance;

a transmission element physically coupled to the second force electrode and configured such that a force biasing the transmission element causes the second force electrode to deflect relative to the first force electrode changing the first variable capacitance, and wherein the transmission element allows a portion of the second substrate to move within the first opening; and

a processing system coupled to the first plurality of capacitive sensor electrodes, the second plurality of capacitive sensor electrodes, the first force electrode, and the second force electrode, wherein the processing system is configured to determine positional information for objects in the sensing region, and wherein the processing system is further configured to determine a first value of the first variable capacitance and determine force information relating to the force biasing the transmission element using the first value.

17. The input device of claim 16 further comprising a vent in at least one of the first, second and third substrates, the vent facilitating gas flow when the second force electrode is deflected relative to the first force electrode.

18. The input device of claim 16 wherein the second substrate comprises polyimide, polyethylene terephthalate, or polycarbonate, and wherein the first substrate comprises a material selected from a group consisting of polyimide, polyethylene terephthalate, polycarbonate, fiberglass, poly(methyl methacrylate), and glass.

19. The input device of claim 18 wherein the input device further comprises a set of routing traces disposed on the second substrate, the set of routing traces coupled to the first set of capacitive sensor electrodes, the second set of capacitive sensing electrodes, and the processing system.

20. A method for measuring user input, the method comprising:

determining a capacitance value of a variable capacitance defined at least in part by a first electrode disposed on a first substrate and a second electrode coupled to a second substrate, wherein the second electrode overlaps the first electrode, wherein a third substrate having an opening is arranged between the first substrate and the second substrate with the opening between at least a portion of the first electrode and at least a portion the second electrode, wherein the opening has an opening area, and wherein a transmission element is physically coupled to the second substrate; and

determining force information from the determined capacitance value about the force of a user input biasing the transmission element relative to the first electrode, causing the second electrode to deflect relative to the first electrode, and changing the variable capacitance;

generating an output indicating the force information; and

capacitively detecting at least one object in a sensing region with a first plurality of capacitive sensor electrodes disposed on at least one of the first substrate, the second substrate, and the third substrate.