Hybrid Capacitance Sensor Array for Finger Contact Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current proximity sensors, particularly those using self-capacitance, face challenges in accurately determining finger contact on a controller due to similar capacitive loading from varying finger sizes and distances, making it difficult to differentiate between a finger extended above the sensor and one in contact.
Innovation Solution
A system combining self-capacitance and mutual capacitance sensors is employed, with mutual capacitance sensors used to detect touch and set threshold limits for self-capacitance measurements, enabling more accurate proximity tracking and contact detection regardless of finger size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If self-capacitance sensors are used to detect finger proximity, then the sensor can detect objects at a distance, but it cannot accurately differentiate between a large object at far range and a smaller object at closer range due to similar capacitive loading
Solution Approach 1:
The patent combines self-capacitance sensors and mutual capacitance sensors into a hybrid sensor array. The self-capacitance sensors detect objects at a distance, while the mutual capacitance sensors provide reference measurements for objects in contact. By merging the data from both sensor types, the system can accurately differentiate between finger contact and proximity regardless of finger size variations.
Solution Approach 2:
The patent changes the measurement parameters by using two different capacitance measurement modes (self-capacitance and mutual capacitance) with different sensitivity characteristics. Self-capacitance measurements are used for proximity detection at larger distances, while mutual capacitance measurements are used for contact detection. The system dynamically adjusts which parameter set to use based on the detection state.
2Reliability
If only self-capacitance sensors are used, then the device structure remains simple, but the system cannot reliably determine finger contact due to similar capacitive loading from varying finger sizes and distances
Solution Approach 1:
The patent merges self-capacitance sensors and mutual capacitance sensors into a unified sensor array system. The self-capacitance sensors are positioned to detect proximity, while mutual capacitance sensors are positioned to detect contact. The combination of these two sensor types improves reliability without requiring a complete redesign of the device structure.
Solution Approach 2:
The sensor array is segmented into different functional zones: self-capacitance sensors for proximity detection and mutual capacitance sensors for contact detection. This segmentation allows each sensor type to operate in its optimal detection range, improving overall system reliability while maintaining manageable device complexity through modular sensor placement.
3Measurement precision
If mutual capacitance sensors are used alone, then contact detection is more accurate, but the system lacks the ability to track proximity at varying distances effectively
Solution Approach 1:
The patent makes the sensor array multi-functional by enabling both self-capacitance and mutual capacitance sensors to serve dual purposes. The self-capacitance sensors can detect both proximity and contact, while mutual capacitance sensors provide reference measurements for both states. This universality reduces the need for additional specialized sensors.
Solution Approach 2:
The patent combines the functionality of proximity detection and contact detection into a unified sensor system. By merging self-capacitance and mutual capacitance measurements, the system achieves precise proximity tracking at varying distances while maintaining accurate contact detection, eliminating the need for separate sensor systems 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 combination allows for precise detection of finger contact and proximity, overcoming the limitations of self-capacitance sensors by leveraging the exponential sensitivity drop-off with distance in mutual capacitance measurements for improved accuracy.
Implementation Method 1
Self-capacitive sensors are also known to those skilled in the art. When a sensor uses self-capacitance to measure proximity of an object to the self-capacitive sensor, it may be difficult to tell the difference between a large object at a far range and a smaller object that is at a closer range
Implementation Method 2
The CIRQUE® Corporation touchpad is a mutual capacitance-sensing device... When a pointing object creates imbalance because of capacitive coupling when the object approaches or touches a touch surface (the sensing area 18 of the touchpad 10), a change in capacitance occurs on the electrodes 12, 14
Data Source
AI summary
Systems and methods are disclosed for using a combination of mutual and self-capacitance sensors to determine when an object, such as a finger, has made contact with a controller, regardless of the size of the object.