Adaptive Touch Detecting Circuit for Interconnection Length Compensation
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Solution Overview
Problem
Existing touch panel control circuits face challenges in accurately detecting touch signals due to variations in interconnection lengths, leading to signal attenuation and reduced detection accuracy, especially for sensor capacitors farther from the detector.
Innovation Solution
A touch detecting circuit that adapts to interconnection lengths by varying detection characteristics, such as threshold values and resistance, to compensate for differences in time constants and improve signal detection sensitivity across all sensor capacitors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a fixed detection threshold is used for all sensor capacitors, then the detection circuit is simple, but detection accuracy deteriorates for sensor capacitors at different distances due to signal attenuation
Solution Approach 1:
The patent applies local quality by setting different detection threshold values for sensor capacitors based on their specific interconnection lengths. The detection threshold is adjusted locally for each sensor capacitor group according to its distance from the detector, compensating for signal attenuation variations and improving detection accuracy without requiring a completely complex adaptive system.
Solution Approach 2:
The patent changes the detection threshold parameter according to interconnection length. By categorizing sensor capacitors into groups based on their distance from the detector and assigning different threshold values to each group, the system adapts to signal attenuation effects while maintaining a relatively simple implementation structure.
2Measurement precision
If the detection threshold is increased to compensate for signal attenuation, then detection sensitivity improves for distant sensor capacitors, but noise interference also increases
Solution Approach 1:
The patent applies local quality by setting different detection threshold values for sensor capacitors based on their specific interconnection lengths. The detection threshold is adjusted locally for each sensor capacitor group according to its distance from the detector, compensating for signal attenuation variations and improving detection accuracy without requiring a completely complex adaptive system.
Solution Approach 2:
The patent uses partial action by applying compensation only to the extent necessary for each distance group. Rather than uniformly increasing the threshold for all sensors (which would excessively amplify noise), the threshold is increased partially and selectively only for sensor capacitors that require compensation due to their specific interconnection lengths, thereby maintaining optimal signal-to-noise ratio.
3Measurement precision
If separate detection parameters are set for each sensor capacitor, then detection accuracy is maximized, but the number of parameters and circuit complexity increases significantly
Solution Approach 1:
The patent applies local quality by setting different detection threshold values for sensor capacitors based on their specific interconnection lengths. The detection threshold is adjusted locally for each sensor capacitor group according to its distance from the detector, compensating for signal attenuation variations and improving detection accuracy without requiring a completely complex adaptive system.
Solution Approach 2:
The patent uses universality by creating a standardized detection parameter setting method that can be applied to all sensor capacitors through categorization. Instead of designing unique parameters for each individual sensor, a universal approach is adopted where sensor capacitors are grouped by interconnection length and assigned standardized threshold values, reducing the total number of parameters while maintaining detection accuracy.
Solution Approach 3:
The patent uses partial action by applying compensation only to the extent necessary for each distance group. Rather than uniformly increasing the threshold for all sensors (which would excessively amplify noise), the threshold is increased partially and selectively only for sensor capacitors that require compensation due to their specific interconnection lengths, thereby maintaining optimal signal-to-noise ratio.
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 enables stable detection of signals from sensor capacitors at varying distances, enhancing touch detection accuracy and reducing noise interference, thereby improving overall touch panel performance.
Implementation Method 1
a pulse-shaped AC drive voltage is repetitively applied to a sensor capacitor from the Y electrode, and electric charges corresponding to a capacitance value of the sensor capacitor at that time are transmitted and are accumulatively added by an integration circuit connected to the X electrode, thereby detecting a capacitance value of the sensor capacitor
Implementation Method 2
The circuit elements are also configured to vary a detection characteristic corresponding to a sensor electrode associated with the sensor capacitor based on an interconnection length to the sensor electrode to compensate for variation in time constants for different sensor capacitors
Data Source
AI summary
A touch detecting circuit is allowed to adaptively operate in accordance with an interconnection length to a sensor capacitor of an object to be detected. For example, the touch detecting circuit has a configuration capable of adjusting a threshold value for determination touch and non-touch or a configuration capable of adjusting detection sensitivity of a detection circuit that is connected to the sensor capacitor. For example, the touch detecting circuit has a configuration which includes an adjustment resistor that is connected in series to a signal line for input from the sensor capacitor at an input portion of the detection circuit, and which is capable of performing adjustment to cancel a difference in an interconnection resistance from a sensor capacitor on a far end side to a sensor capacitor on a near end side.