Capacitive Touch Sensor End-Portion Sensitivity Control
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Solution Overview
Problem
Touch detection sensitivity deteriorates at the end portions of electric capacity type touch sensors due to incomplete area contact, leading to inaccurate touch detection.
Innovation Solution
An electronic device with a control unit that sets different threshold values for electrodes at the end and center portions of a touch sensor array, allowing for precise touch detection by executing processes based on capacity values exceeding specific thresholds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single threshold value is used for all electrodes in the touch sensor, then the device structure is simple and easy to manufacture, but touch detection sensitivity deteriorates at the end portions of the sensor area
Solution Approach 1:
The patent applies local quality by setting different threshold values for different regions of the touch sensor. Specifically, a first threshold value is set for electrodes at the end portion of the sensor area, while a second threshold value (higher than the first) is set for electrodes at the center portion. This regional differentiation improves touch detection sensitivity at the end portions without unnecessarily complicating the overall system, as the threshold configuration is systematically organized by region.
2Measurement precision
If the sensor area is enlarged to ensure complete touch contact, then touch detection accuracy improves, but the device size increases and miniaturization is prevented
Solution Approach 1:
The patent changes the parameter of threshold values to compensate for the insufficient touch contact area at the end portions. By lowering the threshold value at the end portion electrodes compared to the center portion, the system achieves adequate touch detection accuracy without needing to enlarge the sensor area. This parameter adjustment allows the sensor to respond to smaller capacity changes that occur when fingers touch the edge regions.
3Reliability
If a higher threshold value is used to reduce false detections, then detection reliability improves, but touch detection sensitivity at end portions deteriorates
Solution Approach 1:
The patent applies local quality by differentiating threshold values between end portion electrodes and center portion electrodes. The end portion electrodes use a lower first threshold value to maintain sensitivity, while center portion electrodes use a higher second threshold value to ensure reliability. This spatially differentiated approach allows each region to have optimized detection characteristics suited to its specific operational requirements.
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
Enhances touch detection sensitivity and accuracy at the end portions of the sensor area, preventing deterioration in touch operation feeling and allowing for miniaturization of devices without enlarging the sensor area.
Implementation Method 1
The touch sensor of the electric capacity type discriminates the presence or absence of the touch input by setting the threshold value with respect to the change of the capacity value as a sensor output
Implementation Method 2
when an input by the finger or the like is detected, approaching and touching states of the finger are detected by using a difference value between the electric capacity value which is output from the electrode and the base line value
Data Source
AI summary
An electronic device having a plurality of electrodes arranged to detect a touch operation onto an operation plane has a control unit for effecting control such that in a case where a capacity of an electrode arranged at an end portion of an arrangement of the plurality of electrodes is equal to or greater than a first capacity, a process corresponding to the touch operation is executed, and in a case where a capacity of another electrode different from the electrode arranged at the end portion is equal to or greater than a second capacity greater than the first capacity, the process corresponding to the touch operation is executed.