Capacitive Fold Angle Detection Using Differential Electrode Arrays
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Solution Overview
Problem
Conventional foldable devices do not effectively utilize capacitive sensors to detect the fold angle due to issues like temperature sensitivity and display-related errors, instead relying on dedicated gyroscopic, accelerometer, IR, or Hall sensors, which increase complexity and cost.
Innovation Solution
A system using a plurality of electrodes, including at least one first electrode and one second electrode positioned relative to the fold line, where the processing system obtains absolute capacitance measurements from these electrodes to determine the fold angle, canceling out interference effects and eliminating the need for additional sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If dedicated gyroscopic sensors and accelerometers are used to detect fold angle, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The existing capacitive sensor array, originally designed for touch detection, is made multi-functional by utilizing it for both touch input and fold angle detection. The same electrode structure serves dual purposes, eliminating the need for separate dedicated sensors and reducing overall device complexity while maintaining measurement capability.
Solution Approach 2:
The capacitive sensor array performs self-service by simultaneously executing its primary touch detection function and the secondary fold angle measurement function. The existing infrastructure serves itself for additional measurement tasks without requiring external dedicated components, thereby simplifying the system architecture.
2Measurement precision
If dedicated IR sensors or Hall sensors are used to detect closure, then measurement precision is improved, but manufacturing cost increases
Solution Approach 1:
The capacitive sensor array is utilized for multiple functions including touch detection, fold angle measurement, and closure detection. This multi-functionality eliminates the need for separate IR or Hall sensors, reducing component count and manufacturing costs while maintaining precise closure detection capability through the same sensor infrastructure.
3Device complexity
If capacitive sensors are used to detect fold angle, then device complexity is reduced, but measurement precision deteriorates due to temperature sensitivity and display interference
Solution Approach 1:
The harmful effects of temperature sensitivity and display interference are extracted and isolated from the measurement process. By using differential measurement techniques with specifically positioned electrodes, these interfering factors are separated and canceled out, leaving only the genuine fold angle signal for accurate detection.
Solution Approach 2:
The temperature sensitivity and display interference, which are normally harmful factors, are converted into beneficial reference signals. By measuring capacitance changes at multiple electrode positions and analyzing differential patterns, these environmental variations are transformed into useful information that helps cancel out noise and enhance the accuracy of fold angle detection.
4Measurement precision
If multiple electrodes are used for fold angle detection, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The capacitive sensor array is segmented into specific functional zones with electrodes positioned at different locations relative to the fold line. This segmentation allows different electrode groups to serve specific measurement purposes, enabling precise fold angle detection through coordinated reading of multiple segmented electrode signals while maintaining a structured and manageable configuration.
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
This approach allows for accurate and timely fold angle detection, reducing material costs, assembly labor, and simplifying design while avoiding display interference and temperature-related errors, thereby enhancing reliability and reducing the number of components.
Implementation Method 1
capacitive sensor(s) to detect a fold angle of the foldable device
Data Source
AI summary
A system for determining a fold angle of a foldable device includes a plurality of electrodes and a processing system. The plurality of electrodes includes at least one first electrode and at least one second electrode, wherein the at least one second electrode is farther from a fold line of the foldable device than the at least one first electrode. The processing system is configured to: obtain at least one first absolute capacitance measurement via the at least one first electrode and at least one second absolute capacitance measurement via the at least one second electrode; and determine a fold angle of the foldable device based on the at least one first absolute capacitance measurement and the at least one second absolute capacitance measurement.