Interleaved Touch Sensor Electrodes for Linear Capacitive Interpolation
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Solution Overview
Problem
Existing touch sensor technologies require interpolation resistors or impedance elements between active lines, leading to increased fabrication costs and non-linearity, which affect sensitivity and accuracy.
Innovation Solution
The use of interpolation electrode patterning that eliminates impedance elements by creating a bi-linear fall-off in sensitivity through the structure of electrodes, rather than through impedance elements, allowing for a simpler fabrication process and improved linearity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If interpolation resistors or impedance elements are used between active lines, then sensitivity fall-off can be achieved, but fabrication costs increase and non-linearity occurs
Solution Approach 1:
The patent removes interpolation resistors and impedance elements from the touch sensor structure, replacing them with a purely capacitive grid architecture. This extraction eliminates the sources of non-linearity and fabrication complexity while maintaining the necessary sensitivity fall-off through capacitive coupling alone
Solution Approach 2:
The patent substitutes the mechanical/electrical impedance-based sensitivity control with a purely capacitive field-based approach. By using intersecting row and column electrodes that create capacitive coupling, the system achieves sensitivity modulation without physical impedance elements, thereby improving linearity and simplifying fabrication
2Measurement precision
If interpolation resistors are used between active lines, then sensitivity control is achieved, but manufacturing costs increase
Solution Approach 1:
The patent merges the functions of sensitivity control and position detection into a single capacitive grid structure. The intersecting row and column electrodes simultaneously provide both the sensitivity fall-off and the touch position detection, eliminating the need for separate interpolation resistors and reducing manufacturing costs
Solution Approach 2:
The capacitive grid electrodes serve multiple functions: they detect touch position, control sensitivity through their geometric arrangement, and provide the interpolation function traditionally performed by resistors. This multi-functionality reduces component count and fabrication complexity
3Measurement precision
If impedance elements are used to create sensitivity fall-off, then touch detection is enabled, but power consumption increases
Solution Approach 1:
The patent replaces impedance-based signal conditioning with capacitive coupling, which inherently provides the necessary signal modulation without the continuous power consumption associated with active impedance elements. The capacitive grid uses passive electric field interactions to achieve touch detection
Data Source
AI summary
Interpolation electrode patterning for capacitive-grid touch sensor is provided herein. Provided is a device that includes multiple column electrodes that include a first column electrode divided into a plurality of first column sub-electrodes and at least a second column electrode divided into a plurality of second column sub-electrodes. The first column electrode and the second column electrode are adjacent column electrodes. Further, first column sub-electrodes of the plurality of first column sub-electrodes are interleaved with second column sub-electrodes of the plurality of second column sub-electrodes in a first direction. A first layer of the device comprises the multiple column electrodes and a second layer of the device comprises the multiple row electrodes.