Capacitive sensing using discrete lighting elements
First Claim
1. A processing system for a capacitive input device, comprising:
- a first interface coupled to at least one first electrode of at least one lighting element;
a second interface coupled to at least one second electrode of the at least one lighting element spaced apart from the at least one first electrode;
a controller, coupled to the first interface and the second interface, configured to;
forward-bias the at least one lighting element during first time periods to provide illumination;
discharge capacitance of the at least one lighting element between the at least one first electrode and the at least one second electrode during second time periods;
drive the at least one first electrode with a modulated voltage relative to a reference voltage while guarding the at least one second electrode during third time periods; and
receive at least one resulting signal from the at least one first electrode during the third time periods to measure absolute capacitance; and
a determination module, coupled to the controller, configured to determine presence of at least one input object in a sensing region based on changes in the absolute capacitance of each of the at least one first electrode.
3 Assignments
0 Petitions
Accused Products
Abstract
An example processing system for a capacitive input device includes a first interface coupled to at least one first electrode of at least one lighting element and a second interface coupled to at least one second electrode of the at least one lighting element spaced apart from the at least one first electrode. A controller is configured to: forward-bias the at least one lighting element during first time periods to provide illumination; drive the at least one first and the at least one second electrodes with substantially the same voltage during second time periods; and drive the at least one first electrode with a modulated voltage relative to a reference voltage while guarding the at least one second electrode during third time periods to measure capacitance. A determination module is configured to determine presence of at least one input object in a sensing region based on changes in the capacitance.
-
Citations
17 Claims
-
1. A processing system for a capacitive input device, comprising:
-
a first interface coupled to at least one first electrode of at least one lighting element; a second interface coupled to at least one second electrode of the at least one lighting element spaced apart from the at least one first electrode; a controller, coupled to the first interface and the second interface, configured to; forward-bias the at least one lighting element during first time periods to provide illumination; discharge capacitance of the at least one lighting element between the at least one first electrode and the at least one second electrode during second time periods; drive the at least one first electrode with a modulated voltage relative to a reference voltage while guarding the at least one second electrode during third time periods; and receive at least one resulting signal from the at least one first electrode during the third time periods to measure absolute capacitance; and a determination module, coupled to the controller, configured to determine presence of at least one input object in a sensing region based on changes in the absolute capacitance of each of the at least one first electrode. - View Dependent Claims (2, 3, 4, 5, 6, 7)
-
-
8. A capacitive sensing system, comprising:
-
an input device including at least one lighting element having at least one first electrode spaced apart from at least one second electrode; and a processing system having a first interface coupled to the at least one first electrode and a second interface coupled to the at least one second electrode, the processing system including; a controller, coupled to the first interface and the second interface, configured to; forward-bias the at least one lighting element during first time periods to provide illumination; discharge capacitance of the at least one lighting element between the at least one first electrode and the at least one second electrode during second time periods; drive the at least one first electrode with a modulated voltage relative to a reference voltage while guarding the at least one second electrode during third time periods; and receive at least one resulting signal from the at least one first electrode during the third time periods to measure absolute capacitance; and a determination module, coupled to the controller, configured to determine presence of at least one input object in a sensing region based on changes in the absolute capacitance of each of the at least one first electrode. - View Dependent Claims (9, 10, 11, 12)
-
-
13. A method of controlling at least one lighting element for illumination and capacitive sensing, the at least one lighting element comprising at least one first electrode spaced apart from at least one second electrode, the method comprising:
-
forward-biasing the at least one lighting element during first time periods to provide illumination; discharging capacitance of the at least one lighting element between the at least one first electrode and the at least one second electrode during second time periods; driving the at least one first electrode with a modulated voltage relative to a reference voltage while guarding the at least one second electrode during third time periods; receiving at least one resulting signal from the at least one first electrode during the third time periods to measure absolute capacitance; and determining presence of at least one input object in a sensing region based on changes in the absolute capacitance of each of the at least one first electrode. - View Dependent Claims (14, 15, 16, 17)
-
Specification