Multi-Key Force Sensing for Accurate Press Detection
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Solution Overview
Problem
Current algorithms for multi-key devices with force sensors fail to accurately identify the keys pressed by a user, especially when multiple keys are pressed simultaneously or when adjacent keys receive parasitic force signals, leading to incorrect activation of unintended keys.
Innovation Solution
A process that calculates transmission rate values between keys to isolate and remove parasitic forces, using a matrix to determine the actual pressing force applied by the user, allowing precise identification of the keys pressed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If force sensors are used to detect key activation, then the device can detect key presses, but adjacent keys receive parasitic force signals causing false activations
Solution Approach 1:
The patent segments the total force signal into individual key contributions by introducing transmission rate parameters. Each sensor's reading is decomposed into components from different keys based on pre-calculated transmission rates, allowing isolation of the actually pressed key from parasitic signals affecting adjacent keys.
Solution Approach 2:
The patent uses feedback by pre-calculating transmission rate matrices through experimental measurement. The system measures how force applied to each key distributes across all sensors, then uses this feedback information to correctly attribute sensor readings to the actual pressed keys, eliminating false activations.
2Adaptability or versatility
If multiple keys are pressed simultaneously, then the device should identify all pressed keys, but current algorithms incorrectly identify additional adjacent keys
Solution Approach 1:
The patent applies segmentation by decomposing the system of equations representing force distribution across keys and sensors. By solving the matrix equation F = T × S separately for each key contribution, the system can accurately identify multiple simultaneously pressed keys without false positives from adjacent key parasitic signals.
Solution Approach 2:
The patent changes the parameter representation from simple threshold-based detection to a matrix-based parameter system involving transmission rates. This parameter transformation allows the system to handle complex multi-key press scenarios by using the transmission rate matrix to correctly attribute force signals to their source keys.
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 process enables accurate determination of the keys pressed by the user, reducing false activations and improving the precision of key identification in multi-key devices.
Implementation Method 1
force sensors having a resistance sensitive to an applied force (FSR, Force Sensitive Resistor)
Data Source
AI summary
The invention relates to a process for determining the activation of at least one key of a multi-key device. The multi-key device comprises a plurality of keys K1 to Kn and a plurality of force sensors C1 to Cn, each force sensor C1 to Cn being associated respectively with a key K1 to Kn and able to provide a value representing a force which is applied to it. The process is characterized by the fact that it comprises the steps: obtaining values F′1 to F′n representing the force applied to each of the force sensors C1 to Cn; providing transmission rate values of a pressing force between the keys; removing the contribution of each of the force values F′1 to F′n from the pressing force transmitted between the keys using the transmission rate values provided; and determining values F1 to Fn representing the pressing force which has been applied by the user to the keys K1 to Kn.