Phase-Based Touch Sensing for Accurate Hover And Pressure Detection
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Solution Overview
Problem
Existing sensors struggle to detect touch events, such as hover and pressure, with low latency and accuracy, especially in non-contact scenarios, and fail to effectively differentiate between various touch states without physical contact.
Innovation Solution
The implementation of frequency-orthogonal signaling techniques, including frequency-division multiplexing and code-division multiplexing, combined with phase shifting of signals, allows for the detection of touch events through capacitive sensors, enabling the differentiation of touch states and improving signal-to-noise ratio, even in non-contact situations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If frequency-orthogonal signaling techniques are implemented, then measurement precision and signal-to-noise ratio are improved, but device complexity increases
Solution Approach 1:
The patent segments the sensing system into multiple independent frequency channels, each handling specific touch event detection. By dividing the sensing bandwidth into orthogonal frequency components, the system can process multiple touch states simultaneously without interference, improving measurement precision while managing complexity through modular frequency-based segmentation
Solution Approach 2:
The patent changes the frequency parameter of sensing signals to create orthogonal signaling channels. By varying frequency parameters across different sensing channels and using phase shifting techniques, the system achieves better signal differentiation and noise rejection, thereby improving touch event detection accuracy without requiring fundamentally new hardware architectures
2Reliability
If phase shifting of signals is applied, then signal-to-noise ratio and touch state differentiation are improved, but device complexity increases
Solution Approach 1:
The patent applies periodic phase shifting to sensing signals, where the phase of transmitted signals is modulated at specific periodic intervals. This periodic phase modulation creates distinct signal patterns for different touch states, enabling reliable differentiation between hover, contact, and pressure events while using well-established periodic signal processing techniques
Solution Approach 2:
The patent implements feedback mechanisms where the received signals are analyzed for phase relationships, and this information is fed back to adjust and refine touch state classification. The system uses phase difference feedback to continuously optimize the differentiation between various touch states, improving reliability through adaptive signal processing
3Adaptability or versatility
If capacitive sensors are used for non-contact detection, then hover detection capability is improved, but measurement precision for pressure detection deteriorates
Solution Approach 1:
The patent makes the capacitive sensing system universal by enabling it to perform multiple functions: both non-contact hover detection and contact pressure measurement. Through frequency-orthogonal signaling and phase analysis, the same sensor infrastructure can distinguish between different touch modes (hover vs. contact) and measure different parameters (proximity distance vs. applied pressure) with appropriate precision for each function
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 enables fast and accurate detection of touch events with low latency, improving the sensitivity and resolution of touch sensing systems, allowing for precise measurement of proximity, area, and pressure without requiring physical contact.
Implementation Method 1
A sensor, such as a capacitive sensor, may be used to detect changes in capacitance that occur when a conductive or capacitive object, such as a user's finger, a stylus, or another object approaches or touches the sensor
Data Source
AI summary
A person or object is infused with a signal. The infused signal has a phase relationship with the signals that are transmitted from and used by a touch sensor, controller or wearable. The phase relationship of the infused signal is used in order to increase the ability of receivers at or on the touch sensor, controller or wearable to measure and determine touch events, such as hover.