COMBINED FORCE AND TOUCH SENSOR
This disclosure generally provides input devices, processing systems and methods for touch and force sensing utilizing combination sensor conductors. The combination sensor conductors are configurable as capacitive sensor conductors and force sensor conductors via operation of a processing system.
1 . An input device comprising
an input surface;
a plurality of combination sensor conductors comprising:
a first combination sensor conductor configurable between being a first capacitive sensor conductor of a plurality of capacitive sensor conductors and a first force sensor conductor, the first capacitive sensor conductor and the first force sensor conductor sharing a same first conductive portion; and
a second combination sensor conductor configurable between being a second capacitive sensor conductor of the plurality of capacitive sensor conductors and a second force sensor conductor, the second capacitive sensor conductor and the second force sensor conductor sharing a same second conductive portion;
a display configured to display images through the input surface; and
a processing system communicatively coupled to the plurality of combination sensor conductors, the processing system configured to:
determine positional information for an input object present in a sensing region overlapping the input surface using at least the first capacitive sensor conductor of the plurality of capacitive sensor conductors; and
determine force applied to the input surface of the display by the input object based on a change in a first resistance across the first force sensor conductor and a change in a second resistance across the second force sensor conductor.
2 . The input device of claim 1 , wherein the processing system, when determining force applied to the input surface, is configured to determine force further based on the positional information of the input object.
3 . The input device of claim 1 , wherein the processing system, when determining force applied to the input surface, is configured to utilize a resistance across the first force sensor conductor as a baseline when processing the change in resistance across the second force sensor conductor.
4 . The input device of claim 1 , wherein the plurality of capacitive sensor conductors extend across the input surface in a parallel orientation.
5 . The input device of claim 1 , wherein the first and second force sensor conductors are substantially equal in length.
6 . The input device of claim 1 , wherein the first force sensor conductor comprises:
a routing trace extending across the input surface.
7 . The input device of claim 1 , wherein the second force sensor conductor is disposed proximate a center of the input surface, and wherein the first force sensor conductor is disposed proximate a perimeter of the input surface.
8 . A processing system for an input device, comprising:
a driver module configured to:
drive a plurality of combination sensor conductors during a first mode for capacitive sensing, the plurality of combination sensor conductors comprising:
a first combination sensor conductor configurable between being a first capacitive sensor conductor of a plurality of capacitive sensor conductors and a first force sensor conductor of a plurality of force sensor conductors, the first capacitive sensor conductor and the first force sensor conductor sharing a same first conductive portion; and
a second combination sensor conductor configurable between being a second capacitive sensor conductor of the plurality of capacitive sensor conductors and a second force sensor conductor of the plurality of force sensor conductors, the second capacitive sensor conductor and the second force sensor conductor sharing a same second conductive portion; and
drive at least the first and second force sensor conductors during a second mode; and
a receiver module configured to:
receive first resulting signals indicative of a position of the input object interfacing with an input surface of the input device while the driver module is operating in the first mode, and
receive second resulting signals indicative of a force of the input object interfacing with the input surface while the driver module is operating in the second mode.
9 . The processing system of claim 8 further comprising:
a determination module configured to determine the force of the input object interfacing with the input surface based on the second resulting signals, the second resulting signals indicative of a first change in resistance across the first force sensor conductor and of a second change in resistance across the second force sensor conductor.
10 . The processing system of claim 9 , wherein the determination module, when determining force applied to the input surface, is configured to determine force further based on the position of the input object interfacing with the input surface.
11 . The processing system of claim 9 , wherein the determination module, when determining force applied to the input surface, is configured to determine force based on:
a mapping of force versus displacement; and
a capacitive response of the plurality of combination sensor conductors.
12 . The processing system of claim 9 , wherein the determination module, when determining force applied to the input surface, is configured to utilize a resistance across the first force sensor conductor as a baseline for processing a resistance across the second force sensor conductor.
13 . The processing system of claim 8 further comprising:
switching circuitry operable to selectively couple an end of each of the first and second force sensor conductors to the receiver module.
14 . The processing system of claim 8 further comprising:
switching circuitry operable to simultaneously couple the second force sensor conductor and another force sensor conductor of the plurality of force sensor conductors to the driver module through a common routing.
15 . The processing system of claim 14 , wherein the second force sensor conductor and the another force sensor conductor are coupled in parallel.
16 . A method for sensing force and position using an input device, comprising:
driving a plurality of combination sensor conductors during a first mode, the plurality of combination sensor conductors comprising:
a first combination sensor conductor configurable between being a first capacitive sensor conductor of a plurality of capacitive sensor conductors and a first force sensor conductor of a plurality of force sensor conductors, the first capacitive sensor conductor and the first force sensor conductor sharing a same first conductive portion; and
a second combination sensor conductor configurable between being a second capacitive sensor conductor of the plurality of capacitive sensor conductors and a second force sensor conductor of the plurality of force sensor conductors, the second capacitive sensor conductor and the second force sensor conductor sharing a same second conductive portion; and
driving the first force sensor conductor of the plurality of the force sensor conductors during a second mode;
determining a position of an input object interfacing with an input surface of the input device from resulting signals comprising effects of at least one signal driven during the first mode on the plurality of combination sensor conductors; and
determining force of the input object applied to the input surface based on a first change in resistance across the first force sensor conductor and a second change in resistance across the second force sensor conductor occurring during the second mode.
17 . The method of claim 16 , wherein the determining force of the input object applied to the input surface comprises:
compensating for the position of the input object relative to the input surface.
18 . The method of claim 16 , wherein the determining force of the input object applied to the input surface comprises:
processing the second change in resistance across the second force sensor conductor relative to a baseline resistance of the first force sensor conductor.
19 . The method of claim 16 further comprising:
selectively coupling an end of each of the plurality of force sensor conductors to a receiver module.
20 . The method of claim 16 further comprising:
simultaneously coupling the second force sensor conductor and another force sensor conductor of the plurality of force sensor conductors to a driver module through a common routing.