Proximity Gesture Circuit With Selective Electrode Activation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current touch and proximity sensing technologies face challenges such as high manufacturing costs due to excessive die area requirements, susceptibility to non-linearity in capacitance, and performance limitations, particularly in achieving high resolution with fewer channels and lower ADC resolution, while also dealing with parasitic sensitivity issues in analog oscillators.
Innovation Solution
A self-starting transmitter-detector assembly that activates and strongly couples a transmitter signal to nearby objects, using a proximity-activated gesture circuit and capacitive sensor systems with loop filters and feedback control loops to detect impedance changes, allowing for high-resolution sensing with fewer channels and reduced component count, and operating in multiple modes to minimize parasitic sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional touch and proximity sensing technologies are used, then sensing functionality is achieved, but manufacturing costs increase due to excessive die area requirements
Solution Approach 1:
The sensing system is divided into multiple receiver electrodes that can be selectively activated. Instead of using all electrodes simultaneously, the system segments the sensing task across multiple channels that are activated only when needed, reducing the active die area and associated parasitic effects while maintaining sensing resolution.
Solution Approach 2:
The system employs periodic activation of transmitter and receiver electrodes in alternating phases. During non-measurement phases, electrodes are deactivated or placed in high-impedance states, allowing the system to periodically sample capacitance values without continuous signal transmission, thereby reducing average power consumption and parasitic influence.
2Measurement precision
If conventional capacitive sensing is used, then touch detection is achieved, but performance is limited by susceptibility to non-linearity in capacitance
Solution Approach 1:
The system implements feedback control by continuously monitoring capacitance measurements and adjusting electrode activation states accordingly. When capacitance changes indicate a touch event or proximity condition, the feedback mechanism triggers appropriate electrode activation to maintain measurement accuracy and compensate for non-linear capacitance variations.
Solution Approach 2:
The system dynamically changes operating parameters such as electrode activation states, measurement frequencies, and impedance levels based on detected conditions. By adapting these parameters in response to capacitance measurements, the system maintains optimal performance across varying touch and proximity scenarios, reducing susceptibility to non-linearity.
3Measurement precision
If analog oscillators are used for sensing, then capacitance measurement is achieved, but parasitic sensitivity issues arise
Solution Approach 1:
The system extracts and removes the oscillator functionality from continuous operation, activating it only during brief measurement intervals. By taking the oscillating signal out of continuous operation and confining it to specific measurement phases, the system minimizes the time during which parasitic effects can influence the measurement, while still achieving accurate capacitance detection when needed.
Solution Approach 2:
The oscillator is activated periodically rather than continuously, with measurement phases alternating with idle or high-impedance phases. This periodic operation reduces the cumulative impact of parasitic effects on the measurement system, as parasitic capacitances have less time to accumulate and influence the reading during each measurement cycle.
4Measurement precision
If high-resolution sensing is achieved with conventional systems, then measurement precision improves, but device complexity increases due to more channels and higher ADC resolution requirements
Solution Approach 1:
The high-resolution sensing task is segmented across multiple receiver electrodes that share a common measurement pathway. Instead of requiring each channel to independently achieve high resolution, the system segments the spatial sensing task across multiple electrodes while using time-division or selective activation to process their signals through shared high-resolution ADC resources, reducing overall device complexity.
Solution Approach 2:
The receiver electrodes and associated circuitry are designed to serve multiple functions: they can be selectively activated for different measurement zones, they can operate in both active reception and high-impedance isolation modes, and they share common signal processing resources. This multi-functionality allows high-resolution sensing across multiple channels while using a single or fewer ADC resources, reducing device complexity.
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 high-resolution capacitive sensing with lower electronic instrumentation complexity, reducing manufacturing costs and performance limitations, while maintaining sensitivity and accuracy in detecting touch and proximity events.
Implementation Method 1
a method and system for sensing impedance change in the local space between electrodes
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
A proximity-activated gesture circuit includes an activation receiver electrode, a transmitter electrode, additional receiver electrodes, a control circuit, and a signal processor circuit. The control circuit is configured to activate the transmitter electrode and additional receiver electrodes when a capacitance measurement by the activation receiver electrode reaches a threshold. The signal processor circuit is configured to interpret measurements from the additional receiver electrodes as a gesture.