Touch Panel Calibration Using Panel-Wide Capacitance Variation
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Solution Overview
Problem
Existing touch detection devices for capacitance-type touch panels require frequent recalibration, which is inefficient and can lead to incorrect calibration due to temporary changes in base capacitances, such as those caused by conductive materials, leading to improper detection of capacitance changes.
Innovation Solution
A touch detection device with a calibration part that adjusts the capacitance detection range based on predetermined levels of change and variation in base capacitances, performing calibration only when significant changes occur across the entire panel, avoiding temporary changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If calibration is performed every time the touch detection device is activated, then the touch detection accuracy is maintained, but the device complexity and processing load increase significantly
Solution Approach 1:
The patent changes the parameter of calibration frequency from fixed (every activation) to variable (based on actual capacitance change detection). The calibration part detects whether base capacitance has changed beyond a threshold before triggering calibration, allowing the system to adapt calibration timing to actual needs rather than following a rigid schedule.
2Measurement precision
If calibration is performed frequently, then touch detection accuracy is maintained, but unnecessary recalibration occurs when base capacitances have not changed significantly
Solution Approach 1:
The patent implements feedback by having the calibration part continuously monitor base capacitance values and compare them against previously stored calibration data. When the monitored capacitance change exceeds a predetermined threshold, the system triggers calibration; otherwise, it skips calibration. This feedback mechanism prevents unnecessary calibration operations.
3Adaptability or versatility
If the measurement range is set wide to include expected capacitance changes, then adaptability improves, but measurement precision decreases when base capacitance changes greatly due to temporary conductive materials
Solution Approach 1:
The patent makes the measurement range dynamic by adjusting it based on detected base capacitance changes. The calibration part monitors capacitance variations and dynamically resets the measurement range to appropriately include the new base capacitance level while maintaining optimal precision for detecting touch-induced changes.
Data Source
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AI summary
"A touch detection device, a touch panel device, and a touch detection device calibration method" for performing calibration in a situation where performing calibration is appropriate are provided. With a detected capacitance of each electrode regarded as a parasitic capacitance of the electrode, when a sum of amounts of changes in the parasitic capacitances of electrodes is greater than a predetermined threshold value and a variation index value indicating the magnitude of variation in the parasitic capacitances of the electrodes is less than a predetermined threshold value, a calibration controller calibrates each detection circuit of a sense block so as to detect the capacitance of each electrode while setting the parasitic capacitance of the electrode at a center level.