Touch sensor that utilizes a touch area with a single conductive path
AssigneeNXP B.V.
InventorsThomas Suwald, Arne Burghardt
Life of this patent
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Abstract
It is disclosed a touch sensor (100,200,300,400,500,700) for sensing a user touch, comprising an electrically conductive structure (101) having an electrically conductive touch area (103) exposed to the environment; a first capacitor (115) having a first electrode (117) electrically connected with the conductive structure (101); a second capacitor (119) having a first electrode (121) connected to a second electrode (123) of the first capacitor (115); and a driver arrangement (125) connected to the first capacitor and the second capacitor and adapted to perform particular operation steps.
Claims15
A touch sensor for sensing a user touch, comprising:
- an electrically conductive structure having an electrically conductive touch area exposed to the environment and a single electrical output;
- a first capacitor having a first electrode electrically connected with the conductive structure by an electrical path between the single electrical output of the electrically conductive structure and the first electrode;
- a second capacitor having a first electrode connected to a second electrode of the first capacitor;
- and
- wherein the electrical path between the single electrical output of the electrically conductive structure and the first electrode of the first capacitor is the only electrical connection between the electrically conductive structure and the first and second capacitors;
- a driver arrangement connected to the first capacitor and the second capacitor and adapted to perform the operation steps:
- to supply a driving signal to the first capacitor to charge the first capacitor,
- to stop supplying the driving signal to the first capacitor, allowing a charge state of the first capacitor to be influenced by an object electrically contacting the touch area;
- to transfer a charge of the first capacitor to the second capacitor;
- and
- to measure the charge state of the second capacitor.
A method for sensing a user touch, comprising:
- supplying a driving signal to a first capacitor to charge the first capacitor, the first capacitor having a first electrode electrically connected to a single electrical output of a conductive structure by an electrical path;
- stopping supplying the driving signal to the first capacitor,
- touching an electrically conductive touch area exposed to the environment with a finger, the electrically conductive touch area being part of the conductive structure;
- allowing a charge state of the first capacitor to be influenced by the finger touching the electrically conductive touch area;
- transferring a charge of the first capacitor to a second capacitor having a first electrode connected to a second electrode of the first capacitor,
- wherein the electrical path between the single electrical output of the conductive structure and the first capacitor is the only electrical connection between the conductive structure and the first and second capacitors;
- and
- measuring the charge state of the second capacitor;
- the method in particular further comprising:
- indicating a user touch event, if the charge state of the second capacitor reaches or supersedes a charge state threshold.
Dependencies are inferred from the claim text.