Touchscreen Electrode Pressure Sensing and Temperature Compensation
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Solution Overview
Problem
Electronic devices that measure both touch position and pressure require a separate pressure detecting layer, increasing size, thickness, weight, and manufacturing costs.
Innovation Solution
An electronic device that detects touch position based on mutual capacitance and pressure magnitude based on resistance changes using the same electrodes, eliminating the need for a separate pressure detecting layer and compensating for temperature-induced resistance changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a separate pressure detecting layer is added to measure pressure magnitude, then pressure measurement capability is improved, but device size, thickness, weight, and manufacturing costs increase
Solution Approach 1:
The patent combines the pressure detection function with the existing touchscreen electrode layer by measuring resistance changes in the same electrodes used for touch position detection. This merging eliminates the need for a separate pressure detecting layer, thereby reducing device size, thickness, weight, and manufacturing costs while maintaining pressure measurement capability
Solution Approach 2:
The electrode layer is made multi-functional by enabling it to perform both touch position detection (through mutual capacitance measurement) and pressure magnitude detection (through resistance change measurement). This universal usage of the same component for multiple functions avoids adding extra hardware layers
2Measurement precision
If resistance change is used to detect pressure magnitude, then pressure measurement is enabled, but temperature-induced resistance changes cause measurement errors
Solution Approach 1:
The patent introduces a reference electrode that is not subjected to touch pressure but experiences the same temperature changes as the target electrode. This reference electrode serves as a mediator to measure temperature-induced resistance changes, which are then used to compensate for errors in the target electrode's resistance measurement, improving measurement reliability under temperature variation
Solution Approach 2:
The system implements a feedback mechanism where the resistance change of the reference electrode (representing temperature effect) is measured and used to compensate for the resistance change of the target electrode. This feedback loop enables the system to distinguish between resistance changes caused by pressure and those caused by temperature, maintaining measurement accuracy
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
Enables accurate measurement of pressure without additional hardware, reducing size, weight, and manufacturing costs while maintaining precise pressure detection.
Implementation Method 1
The electronic device may detect the change in the mutual capacitance due to the changed magnitude and detect the position of the touch based on the electrodes where mutual capacitance is changed
Implementation Method 2
detects the magnitude of the pressure of the touch based on a change in resistance due to pressure on the same electrodes
Implementation Method 3
A resistance change characteristic corresponding to a change in temperature of the target electrode may be substantially the same as a resistance change characteristic corresponding to a change in temperature of the reference electrode
Data Source
Figure 1
Figure 2~3A
Figure 3B~3C
AI summary
An electronic device is provided. The electronic device includes a sensor layer including a first channel including one or more first electrodes and a second channel including one or more second electrodes and a control circuit configured to detect touch information corresponding to an input of an external object to the sensor layer based on a change in capacitance between at least one of the one or more first electrodes and at least one of the one or more second electrodes and detect pressure information corresponding to the input based on a resistance changed by the input to at least one of the first channel or the second channel.