Force Sensor Assembly Using Pressure Decay and Gap Distance Sensors
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Solution Overview
Problem
Existing electronic devices face challenges in detecting the amount of force applied to touch-sensitive interfaces without using complex and expensive sensor arrays, which occupy significant space and increase device size.
Innovation Solution
The implementation of a force sensor assembly within the electronic device's internal volume, comprising a pressure decay sensor and a gap distance sensor, which detect changes in pressure and gap distance to calculate the applied force using a weighted combination of signals based on the exponential time constant of pressure decay.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If complex sensor arrays are used to detect force applied to touch-sensitive interfaces, then measurement precision is improved, but device complexity and size increase
Solution Approach 1:
The force sensor assembly is divided into two independent sensor types: a pressure decay sensor and a gap distance sensor. Each sensor measures different aspects of the touch interaction, and their signals are combined to achieve accurate force detection. This segmentation allows the system to maintain high measurement precision while avoiding the complexity of a single comprehensive sensor array.
Solution Approach 2:
The pressure decay sensor serves multiple functions: it detects both the magnitude of applied force and the characteristics of pressure decay over time. The gap distance sensor simultaneously measures both the distance to the touch-sensitive interface and the force applied. This multi-functionality reduces the need for separate specialized sensors, thereby reducing overall device complexity.
2Measurement precision
If complex sensor arrays are used to detect force applied to touch-sensitive interfaces, then measurement precision is improved, but the volume occupied by sensors increases
Solution Approach 1:
By segmenting the force detection function into two separate sensor types (pressure decay sensor and gap distance sensor), each sensor can be miniaturized and optimized for its specific measurement task. This segmentation allows the overall sensor assembly to occupy less volume than a comprehensive single sensor array would require.
Solution Approach 2:
The patent replaces complex mechanical sensor arrays with a combination of pressure decay sensing and capacitive gap distance sensing. The pressure decay sensor uses pressure changes in a sealed cavity to infer force, and the gap distance sensor uses capacitive changes to measure distance and force. This substitution reduces the mechanical complexity and volume of the sensor assembly.
3Measurement precision
If sensor arrays are used to detect force applied to touch-sensitive interfaces, then measurement precision is improved, but the space available for additional components is reduced
Solution Approach 1:
The force detection capability is segmented into two compact sensor types that can be arranged efficiently within the device housing. This segmentation allows the sensor assembly to occupy minimal internal volume while maintaining accurate force detection, thereby preserving more space for additional components.
Solution Approach 2:
The patent replaces bulk mechanical sensor arrays with compact pressure decay and capacitive gap distance sensors. These sensors require minimal space within the device housing, as they can be integrated into the existing structure without requiring large dedicated volumes, thus preserving internal space for other components.
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 solution allows for accurate and reliable detection of force applied to touch-sensitive interfaces without the need for extensive sensor arrays, thereby reducing device size and increasing available space for additional components.
Implementation Method 1
a pressure decay sensor disposed in the internal volume to detect an amount of force applied to the interface surface above a threshold
Implementation Method 2
The gap distance sensor can detect a change in a capacitance associated with the gap to detect the change in the distance
Data Source
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AI summary
An electronic device can include a housing and an interface component. The interface component can at least partially define an interface surface, and the interface component and the housing can define an internal volume. A force sensor assembly can be disposed in the internal volume to detect an amount of force applied to the interface surface. The force sensor assembly can include a pressure decay sensor and a gap distance sensor disposed opposite a surface of the interface component.