Reconfigurable Touch Sensor Circuit Topology for Proximity Detection
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Solution Overview
Problem
Touch sensor panels face limitations in detecting proximity events due to their constrained ability to sense beyond a limited range, and existing technologies struggle to efficiently switch between mutual capacitance and self-capacitance modes while minimizing parasitic noise from proximal electronics.
Innovation Solution
A touch sensor panel configured to switch between mutual capacitance and self-capacitance modes by reusing common circuitry, where drive lines act as sense electrodes in one configuration and sense lines act as sense electrodes in another, with the use of switches to interleave sensing modes and mitigate parasitic noise through driven shielding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Difficulty of detecting and measuring
If mutual capacitance topology is used for proximity detection, then detection capability is improved, but device complexity increases due to additional circuitry requirements
Solution Approach 1:
The patent makes existing drive lines and sense lines serve dual purposes: in mutual capacitance mode, drive lines drive signals and sense lines sense capacitance changes; in self-capacitance mode, the same lines are reconfigured where driven shield lines provide shielding while the same circuitry performs sensing functions. This multi-functionality eliminates the need for separate dedicated shielding circuitry.
Solution Approach 2:
The patent combines the shielding function with the existing driven shield lines that are already part of the mutual capacitance architecture. By reconfiguring these existing lines to provide active shielding during self-capacitance mode, the patent merges two functions (shielding and signal transmission) into a single integrated system, reducing overall device complexity.
2Difficulty of detecting and measuring
If self-capacitance configuration is used to extend detection range, then detection range is improved, but measurement precision deteriorates due to parasitic noise from proximal electronics
Solution Approach 1:
The patent applies preliminary anti-action by configuring driven shield lines to actively counteract parasitic noise before it can interfere with measurements. The shield lines are pre-configured with opposite polarity signals that cancel out the electromagnetic interference from proximal electronics, thereby protecting the weak capacitive signals from noise contamination.
Solution Approach 2:
The driven shield lines act as intermediaries between the noisy environment and the sensitive capacitive sensing elements. These shield lines intercept and divert parasitic noise away from the measurement circuitry, mediating the interaction between external interference and the internal sensing system to preserve signal integrity.
3Adaptability or versatility
If separate circuitry is used for mutual capacitance and self-capacitance modes, then adaptability is improved, but device complexity increases
Solution Approach 1:
The patent implements dynamic reconfiguration of the circuit topology using switch elements that can change the connectivity and functional role of each line based on the operating mode. The same physical infrastructure dynamically adapts its configuration: lines are switched between drive and sense roles, and shield lines are activated or deactivated based on whether mutual or self-capacitance mode is active, eliminating the need for separate dedicated circuitry for each mode.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables efficient detection of touch and proximity events across a wider range while minimizing the number of electrical components and parasitic noise, allowing the panel to operate effectively in both capacitance modes with reduced complexity and noise interference.
Implementation Method 1
Mutual capacitance touch sensor panels can be formed from a matrix of drive and sense lines of a substantially transparent conductive material
Implementation Method 2
The lines are often arranged orthogonally on a substantially transparent substrate
Implementation Method 3
minimizing parasitic noise caused by proximal electronics
Data Source
AI summary
A touch sensor panel configured to switch between a mutual capacitance touch sensing architecture and a self-capacitance touch sensing architecture is provided. The touch sensor panel includes circuitry that can switch the configuration of touch electrodes to act as either drive lines in a mutual capacitance configuration or as sense electrodes in a self-capacitance configuration. The touch sensor panel also includes circuitry that can switch the configuration of touch electrodes to act as either sense lines in a mutual capacitance configuration or as sense electrode in a self-capacitance configuration. By splitting a self-capacitance touch mode into a drive line self-capacitive mode and sense line self-capacitive mode, the touch sensor panel is able to reuse components thus requiring less space, weight and power.