Capacitive Touch Sensor Edge Area Threshold Segmentation
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Solution Overview
Problem
As display monitors in devices like mobile phones and digital cameras become larger, there is a higher likelihood of fingers accidentally touching the screen, leading to unintended actions due to the proximity of fingers holding the device to the touch panel, causing erroneous operations.
Innovation Solution
A capacitive touch sensor system with a processor and controller that distinguishes between intended touch inputs and unintended proximity by setting different capacitance thresholds for the edge and central areas of the sensor, ignoring or disabling processing for unintended touches in the edge area to prevent erroneous operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the display monitor is made larger to improve ease of viewing, then the viewing area increases, but the likelihood of fingers accidentally touching the screen increases causing erroneous operations
Solution Approach 1:
The touch sensor is divided into multiple detection areas with different thresholds: a first detection area (edge region) with a first threshold and a second detection area (central region) with a second threshold. This segmentation allows different sensitivity levels in different regions of the touch sensor.
Solution Approach 2:
Different threshold values are assigned to different regions of the touch sensor. The edge region has a higher threshold to prevent false detection of fingers holding the device, while the central region has a lower threshold to maintain sensitivity for intentional touches. This local differentiation resolves the contradiction between large display size and operation accuracy.
2Device complexity
If a single threshold is used for the entire touch sensor to maintain simplicity, then the device complexity is reduced, but erroneous operations occur when fingers are near the screen edge
Solution Approach 1:
The touch sensor detection areas are segmented into multiple regions (first detection area and second detection area) with different threshold characteristics. This segmentation enables the system to distinguish between fingers holding the device (edge region) and intentional touch operations (central region).
Solution Approach 2:
Different threshold values are applied locally to different regions of the touch sensor. The edge region uses a higher threshold to ignore proximity fingers, while the central region uses a lower threshold for sensitive detection. This local quality differentiation maintains reliability without excessive complexity.
3Measurement precision
If the threshold for touch detection is lowered to improve sensitivity, then touch detection accuracy improves, but unintended actions occur when fingers are close to the screen
Solution Approach 1:
The touch sensor employs different threshold values for different regions: a lower second threshold in the central detection area for high sensitivity to intentional touches, and a higher first threshold in the edge detection area to filter out proximity fingers. This local quality approach resolves the contradiction between sensitivity and reliability.
Solution Approach 2:
The detection areas are segmented into edge region and central region with different threshold characteristics. This segmentation allows the central region to maintain high sensitivity (lower threshold) while the edge region prevents false detections (higher threshold), resolving the contradiction between measurement precision and reliability.
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
Effectively prevents erroneous operations by accurately differentiating between intended touch inputs and unintended proximity, ensuring accurate user interactions even when fingers are close to the screen edge.
Implementation Method 1
a capacitive touch sensor including a sensor area, a processor configured to perform, upon detection by the capacitive touch sensor of a capacitance increase greater than or equal to a first threshold
Data Source
AI summary
A touch sensor driver circuit drives a capacitive touch sensor to detect the presence of an operation performed with a conductive member and detects a position of the operation. A controller performs processing corresponding to the operation on the touch sensor with the conductive member. In a case where detection of a capacitance greater than or equal to a threshold in an edge area of a sensor area of the capacitive touch sensor and a touch operation in a central area that is the sensor area excluding the edge area occur at the same time, the controller ignores the touch operation.