Capacitive Touch Panel Defect Detection via Variable Integration Windows
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Solution Overview
Problem
Conventional capacitive sensing devices in touch panels are susceptible to damage from physical deformation and bending, leading to erroneous readings and false touch detections due to changes in electrode conductive properties, which existing technologies fail to efficiently mitigate.
Innovation Solution
The implementation of variable time receive electrode sensing current integration windows and computations to distinguish between normal and defective electrodes, with corrective operations to mitigate defects, thereby prolonging the sensing device's operation and reducing deleterious effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional capacitive sensing devices are used, then touch and hover detection can be performed, but the devices are susceptible to damage from physical deformation and bending, leading to erroneous readings and false touch detections
Solution Approach 1:
The system performs preliminary defect detection by analyzing electrode conductive properties before normal operation. The processor identifies defective electrodes through computations on sensing currents, and corrective operations are pre-configured to mitigate detected defects, preventing erroneous readings before they occur during normal touch detection
Solution Approach 2:
The system continuously monitors electrode conductive properties by analyzing sensing currents from receive electrodes. The processor compares measured currents against expected values and provides feedback to identify defective electrodes, enabling real-time detection and correction of damage from physical deformation
2Duration of action of stationary object
If electrode damage occurs, then the sensing device can still function, but it produces erroneous readings and false touch detections due to changes in conductive properties
Solution Approach 1:
The system extracts and identifies defective electrodes by analyzing sensing currents from individual receive electrodes. Once a defective electrode is identified through computations showing abnormal conductive properties, the system excludes that specific electrode from normal operation, removing its harmful influence on measurement precision while allowing the rest of the device to continue functioning
Solution Approach 2:
The system discards data from defective electrodes by identifying them through defect detection operations and excluding them from touch detection computations. This allows the sensing device to recover and maintain accurate measurements using only functional electrodes, preserving measurement precision despite physical damage
3Reliability
If defect detection and corrective operations are implemented, then accurate touch detection can be maintained, but the device complexity increases
Solution Approach 1:
The processor performs multiple functions using the same hardware resources: it drives transmit electrodes, receives sensing currents from receive electrodes, computes electrode conductive properties for defect detection, and executes corrective operations. This multi-functionality maintains reliability while minimizing additional device complexity by reusing existing components
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
This approach effectively detects defects in sensing devices and performs corrective operations to maintain accurate touch and hover detection, extending the lifespan and safe operation of capacitive sensing devices.
Implementation Method 1
capacitive sensing may be used to identify such touches and hovers based on capacitive measurements obtained from a sensing device
Data Source
AI summary
Systems, methods, and devices detect defects in touch panels. Methods include scanning, using a designated integration window, a plurality of electrodes of a sensing device to obtain a plurality of measurements and determining a plurality of variance values for the plurality of electrodes based on the plurality of measurements, the plurality of variance values identifying variances in the plurality of measurements between adjacent sense locations of the sensing device. Methods also include determining if a defect is present in the sensing device based, at least in part, on a comparison of the plurality of difference values with the plurality of threshold values.