Push Amount Sensor Reference Potential Reset
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Solution Overview
Problem
Conventional touch input devices using piezoelectric sensors face precision issues in measuring push amounts due to changes in reference potential during repeated operations, leading to decreased measurement accuracy.
Innovation Solution
A touch input device with a piezoelectric sensor and a touch detecting sensor that integrates push signals and resets the reference potential based on touch state changes, using a push amount calculating unit that switches between integration and reset processing, ensuring a fixed reference potential and maintaining high precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If signal levels are integrated continuously without resetting reference potential, then the device structure is simple, but measurement precision deteriorates due to reference potential drift
Solution Approach 1:
The patent applies periodic action by resetting the reference potential at specific intervals triggered by touch detection. The push amount calculating unit periodically resets the reference potential to the current output signal level when a touch is detected, rather than continuously or never resetting. This periodic reset maintains measurement precision while avoiding unnecessary complexity.
Solution Approach 2:
The patent uses feedback by detecting the touch state and using this information to control the reference potential resetting. The push amount calculating unit monitors the touch detection signal and adjusts the reference potential accordingly - resetting when touch is detected and maintaining integration when no touch is present. This feedback mechanism ensures precise measurement while keeping processing logic simple and condition-based.
2Measurement precision
If reference potential is reset frequently, then measurement precision is maintained, but productivity deteriorates due to repeated resetting operations
Solution Approach 1:
The reference potential is reset periodically based on touch detection events rather than at fixed time intervals or continuously. This event-driven periodic action ensures precision is maintained only when necessary (during/after touches) while maximizing productivity during normal operation by avoiding unnecessary resets.
Solution Approach 2:
The system uses the touch detection signal itself to trigger the reference potential reset, making the system self-regulating. The touch detection unit automatically provides the trigger signal to the push amount calculating unit, which then resets the reference potential without external intervention. This self-service mechanism maintains precision while minimizing unnecessary processing operations.
3Measurement precision
If integration processing is continuous, then productivity is high, but measurement precision deteriorates due to accumulating errors from reference potential changes
Solution Approach 1:
The patent applies dynamics by making the processing mode (integration vs. reset) dynamic and adaptable based on touch state. The push amount calculating unit dynamically switches between continuous integration processing and reference potential reset processing according to real-time touch detection signals. This dynamic adjustment maintains measurement precision while keeping the processing switching logic simple and condition-based.
Solution Approach 2:
The system uses feedback from the touch detection unit to control the processing mode. When touch is detected, the feedback signal triggers a reset; when no touch is present, the feedback signal allows continuous integration. This simple feedback-based switching mechanism achieves precise measurement without complex processing control logic.
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 maintains high precision in detecting push amounts and touch positions, preventing erroneous detections by stabilizing the reference potential and integrating the push amount calculating unit with a bypass circuit or digital IC, resulting in improved measurement accuracy and device compactness.
Implementation Method 1
a piezoelectric sensor which outputs a push signal corresponding to a displacement amount obtained when an operation surface is pushed
Data Source
AI summary
A touch input device includes a touch panel, a push amount calculating unit and a touch detection signal generating unit. The touch panel includes piezoelectric and electrostatic sensors. The piezoelectric sensor outputs to the push amount calculating unit a push signal corresponding to a displacement amount obtained by pushing an operation surface. The electrostatic sensor outputs touch signals, corresponding to a touch and a non-touch, to a touch detection signal generating unit. The touch detection signal generating unit outputs to the push amount calculating unit the touch detection signals binarized according to the touch and non-touch state. The push amount calculating unit integrates differences between push signals and a reference potential during a touch state, generates a push amount detection signal and outputs the push amount detection signal. This unit resets a reference potential during a period in which a touch detection signal indicating a non-touch state is inputted.