Capacitive Lid State Detection for Foldable Devices
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Solution Overview
Problem
Existing methods for detecting the state of foldable electronic devices, such as PCs, using Hall sensors are costly, complex, and prone to false detections due to magnetic interference and proximity-based measurements rather than real contact detection.
Innovation Solution
The use of differential charge variation sensors, integrated into the device, which detect environmental electric and electrostatic charge variations to determine the open or closed state by measuring the contact between the sensors, eliminating the need for Hall sensors and magnets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If Hall sensors and magnets are used to detect the state of the foldable device, then the detection function is achieved, but the device structure becomes more complex and cost increases
Solution Approach 1:
The patent removes the Hall sensor and magnet components from the device structure, extracting only the essential detection function through a simplified capacitive sensing approach using the touchscreen controller, thereby reducing structural complexity while maintaining detection capability
Solution Approach 2:
The patent replaces the mechanical magnetic field detection system (Hall sensor + magnet) with an electrical capacitive sensing system that uses the existing touchscreen controller to detect lid position through changes in capacitance, eliminating the need for separate magnetic components
2Reliability
If Hall sensors and magnets are used to detect the state of the foldable device, then the detection function is achieved, but the overall cost of the device increases
Solution Approach 1:
The patent makes the touchscreen controller perform multiple functions: it serves both as the user interface for touch input and as the sensing mechanism for detecting lid state, thereby eliminating the need for dedicated Hall sensors and magnets and reducing overall component cost
Solution Approach 2:
The patent enables the touchscreen controller to self-serve the dual purpose of user interaction and environmental sensing (lid position detection), removing the need for additional specialized components and reducing manufacturing complexity and cost
3Reliability
If Hall sensors are used to detect the state of the foldable device, then the detection function is achieved, but magnetic interference occurs affecting the PC compass and causing unwanted effects
Solution Approach 1:
The patent replaces the magnetic field-based detection system with an electrical capacitive sensing system that detects lid position through changes in capacitance values, completely eliminating magnetic fields and thus removing interference with the PC compass and other magnetic-sensitive components
4Reliability
If Hall sensors are used to detect the state of the foldable device, then the detection function is achieved, but false detections occur when the screen is close but not in actual contact with the keyboard
Solution Approach 1:
The patent monitors changes in capacitance values over time and uses threshold-based detection to distinguish between near-contact and actual contact states, thereby improving measurement precision and eliminating false detections that occur with proximity-based magnetic sensing
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 method accurately detects the state of the device without the drawbacks of Hall sensors, reducing complexity and cost while ensuring precise contact detection, thereby enhancing user experience and device functionality.
Implementation Method 1
differential acquisition, through charge variation sensors, of charge variation signals indicative of environmental electric and/or electrostatic charge variations induced on said charge variation sensors
Data Source
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Figure 3A~3D
AI summary
Detection method (50) of a first or second state of a foldable electronic device (10) comprising a first and a second hardware element (12; 14) tiltable to each other and accommodating a first and a second electrode (20b; 22b) which are in contact with each other when the foldable electronic device is in the first state and at a distance from each other otherwise. The detection method (50) is performed by a control unit (23) of the foldable electronic device and comprises the steps of: acquiring (S10) a first and a second charge variation signal indicative of environmental electric/electrostatic charge variations detected by the first and second electrodes; generating (S12) a differential signal (SD) indicative of a difference between the first (SQ1) and the second (SQ2) charge variation signals; generating (S14, S16, S18, S20), as a function of the differential signal (SD), one or more feature signals (ST); and generating (S22), as a function of the one or more feature signals (ST), a contact signal (Sc) indicative of the first or second states of the foldable electronic device (10) .