Input device with force sensing

• US 9,057,653 B2
• Filed: 05/11/2010
• Issued: 06/16/2015
• Est. Priority Date: 05/11/2010
• Status: Active Grant

• Current Assignee: Synaptics Incorporated
• Original Assignee: Synaptics Incorporated
• Inventors: Schediwy, Richard R., Bolender, Robert J., Schwartz, Adam, Day, Shawn P., Norby, Fritz
• Primary Examiner(s): EURICE, MICHAEL
• Application Number:
  US12/777,829
• Publication Number:
  US 20110278078A1
• Time in Patent Office: 1,862 Days
• Field of Search: 178/18.01, 178/18.03, 178/18.06, 178/20.01, 345/173, 345/174, 345/178, 345/156, 738/626.26, 737/80, 702/41, 702/104, 324/661, 200/600
• US Class Current: 1/1
• 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 including a force sensor and a touchpad, the input device comprising:

a first force electrode disposed on a first substrate;

a second force electrode coupled to a second substrate, the second force electrode overlapping the first force electrode to form a first variable capacitance;

a third force electrode disposed on the first substrate;

a fourth force electrode coupled to the second substrate, the fourth force electrode overlapping the third force electrode to form a second variable capacitance;

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

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

the touchpad comprising a first plurality of capacitive sensor electrodes disposed on the first substrate, the first plurality of capacitive sensor electrodes configured to detect objects in a sensing region disposed between the first opening and the second opening; and

a processing system conductively coupled to the first force electrode, the second force electrode, the third force electrode, the fourth force electrode, and the first plurality of capacitive sensor electrodes, the processing system configured to determine a first capacitance value of the first variable capacitance and a second capacitance value of the second variable capacitance, the processing system being further configured to determine force information using the first and second capacitance values;

wherein the processing system is further configured to determine positional information of objects in the sensing region using the first plurality of capacitive sensor electrodes.

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

3. 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.

4. The input device of claim 1, wherein the processing system is further configured to determine the first variable capacitance by driving the first force electrode with a first sensing signal modulated relative a system ground, driving the second force electrode with a constant potential, and measuring the first variable capacitance from the first force electrode.

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

6. The input device of claim 5,

wherein the processing system is further configured to determine the first variable capacitance by driving the first force electrode with a sensing signal modulated relative a system ground, receiving a resulting signal on the second force electrode, and determining the first variable capacitance from the second force electrode.