Piezoelectric Touch Detection with Dynamic Force Adaptation
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Solution Overview
Problem
Existing touch user interfaces face challenges in accurately detecting the position of a finger, especially with varying force applications and movement, and capacitive detection is unreliable when users wear gloves.
Innovation Solution
A device with a surface featuring piezoelectric elements that convert mechanical stress into voltage, including both impulse and vibrational components, which are calculated by a computing device to determine the object's position with improved accuracy and reliability, and provide haptic feedback.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If piezoelectric elements are used to detect touch with varying force, then the device can detect light touches, but it becomes challenging to function reliably when greater force is applied
Solution Approach 1:
The system dynamically adjusts its detection parameters based on the detected force magnitude. When light touch is detected, the system uses high-gain amplification and low-frequency filtering to maximize sensitivity. When greater force is applied, the system automatically adjusts gain and filtering parameters to prevent saturation and maintain reliable detection across the full force range.
Solution Approach 2:
The patent changes detection parameters including amplification gain, filtering characteristics, and sampling rates based on the detected force level. This allows the system to optimize its response for both light touches (requiring high sensitivity) and heavier presses (requiring saturation prevention), resolving the contradiction between sensitivity and reliability under varying force conditions.
2Adaptability or versatility
If the finger moves on the surface, then the user can interact with different areas, but this movement causes challenges for accurate detection
Solution Approach 1:
The system performs preliminary detection of vibrational characteristics before the finger fully contacts and moves across the surface. By detecting the initial vibrational impulse and anticipating finger movement, the system can pre-adjust its detection window and sampling rate to maintain accurate position tracking throughout the movement, rather than reacting after position errors have occurred.
Solution Approach 2:
The system continuously monitors vibrational signals and provides real-time feedback to adjust position calculations. As the finger moves, the changing vibrational pattern is fed back to the detection algorithm, which dynamically updates the position estimate to compensate for movement-induced detection challenges, maintaining accuracy across the entire surface interaction.
3Reliability
If capacitive touch detection is used, then the interface can detect finger presence, but it does not function properly when the user is wearing gloves
Solution Approach 1:
The patent replaces capacitive detection (which relies on electrical properties and fails with gloves) with piezoelectric detection (which relies on mechanical stress). Piezoelectric elements generate electrical signals in response to mechanical deformation caused by finger pressure, a mechanism that works effectively through gloves since it detects the mechanical force rather than electrical charge, thus resolving the contradiction between reliability and adaptability to different operating conditions.
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
The solution enables precise and reliable touch detection and tracking, even with light touches and through gloves, by utilizing both impulse and vibrational components, and provides localized haptic feedback.
Implementation Method 1
a plurality of elements arranged on the second side of the surface, wherein each element in the plurality of elements is configured to: convert a mechanical stress in the element induced by a force exerted onto the first side of the surface by an object into a voltage
Data Source
AI summary
It is an object to provide a device that may detect touch. According to an embodiment, device comprises a surface comprising a first side and a second side. The device may further comprise a plurality of elements arranged on the second side of the surface. Each element in the plurality of elements may be configured to convert a mechanical stress in the element induced by a force exerted onto the first side of the surface by an object into a voltage. The device may further comprise a computing device electrically coupled to each element in the plurality of elements. The computing device may be configured to calculate a position of the object on the surface. A device, a method, and a computer program product are provided.