Touch Detection Device with Correction Electrode for Noise Reduction
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Solution Overview
Problem
Existing touch detection devices, particularly electrostatic capacitance type, face challenges in accurately detecting object approaches or touches due to variations in input detection signals, leading to reduced detection accuracy and potential false detections caused by noise or changes in power sources and temperature.
Innovation Solution
A touch detection device that includes a drive unit supplying an excitation signal with variable magnitude to a first electrode, a detection unit coupled to a second electrode, and an element with electrostatic capacitance, which corrects output values from the second electrode using simultaneous output values from both the second electrode and the element, thereby improving detection accuracy by synchronizing the excitation signal and correction processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If drive voltages are sequentially supplied to drive lines and then to correction electrode, then correction of input detection signal is achieved, but time difference occurs between object detection and correction, reducing detection accuracy
Solution Approach 1:
The correction electrode is driven simultaneously with the drive lines during the same timing, eliminating the time delay between detection and correction. This preliminary synchronization ensures that correction data is available when needed for accurate object detection without sequential processing delays.
Solution Approach 2:
The system uses the correction electrode to provide real-time feedback on signal variations, which are then used to correct the input detection signal immediately. This feedback mechanism operates concurrently with the detection process, maintaining detection accuracy while eliminating time differences between measurement and correction.
2Measurement precision
If correction electrode and correction detection electrode are provided on positions having no influence of finger touching, then variation in input detection signal is corrected, but device complexity increases
Solution Approach 1:
The correction electrode serves multiple functions: it detects signal variations caused by environmental factors (temperature, power source changes) and simultaneously provides correction data for the entire touch detection system. This multi-functional approach reduces the need for separate correction mechanisms and minimizes overall device complexity.
Solution Approach 2:
The system monitors changes in electrical parameters (capacitance, impedance) of the correction electrode to detect environmental variations. By tracking these parameter changes in real-time, the system can correct detection signals without adding complex hardware, using software-based compensation algorithms that respond to measured parameter variations.
3Device complexity
If electrostatic capacitance type touch detection is used, then configuration is simple and power consumption is low, but detection accuracy is reduced due to noise and environmental variations
Solution Approach 1:
The correction electrode acts as an intermediary that measures environmental noise and variations separately from the main detection electrodes. By capturing these干扰 factors through the correction electrode, the system can subtract or compensate for their effects on the detection signal, maintaining the simplicity of the electrostatic capacitance design while improving accuracy through noise cancellation.
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
The solution enhances the reliability of touch detection by accurately correcting output values and reducing noise influences, leading to improved detection accuracy and suppression of false positives, even in environments with varying power sources and temperatures.
Implementation Method 1
an element that electrically couples the drive unit and the detection unit, receives the excitation signal from the drive unit, and has a predetermined size of electrostatic capacitance
Data Source
AI summary
According to an aspect, a touch detection device includes a drive unit that supplies an excitation signal having at least variable magnitude to a first electrode at a predetermined period for detecting approach or a touch of an object; a detection unit electrically coupled to a second electrode provided to be opposed to the first electrode to detect approach or a touch of the object according to an output value from the second electrode; and an element that electrically couples the drive unit and the detection unit, receives the excitation signal from the drive unit, and has a predetermined size of electrostatic capacitance. The touch detection device corrects an output value from the second electrode by using an output value from the element and the output value from the second electrode obtained at the same timing.