Encapsulated Pressure Sensor Fluid-Force Transmission
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Solution Overview
Problem
Conventional force sensors, such as semiconductor and metallic strain gauges, face challenges in achieving high precision and sensitivity, particularly in detecting low forces like those applied in active styluses, which are essential for accurate pressure measurement in applications like smart pens and robotic gripping devices.
Innovation Solution
The development of encapsulated pressure sensors featuring a pressure sensing surface attached to a mounting substrate, surrounded by a deformable encapsulating member filled with a fluid, where the deformation of the member increases fluid pressure proportional to the applied force, allowing for sensitive force detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional force sensors (semiconductor strain gauges) are used, then high precision is achieved, but the device size becomes relatively large
Solution Approach 1:
The patent combines a pressure sensor with a deformable encapsulating member filled with fluid to create an integrated force sensing system. The pressure sensor and fluid-filled chamber work together as a unified structure, where the deformable member transmits force through fluid pressure to the sensor, achieving compact force measurement without requiring separate large-scale strain gauge components
Solution Approach 2:
The patent uses a fluid-filled deformable encapsulating member to transmit applied force as pressure changes to the pressure sensor. This pneumatic/hydraulic transmission mechanism allows force measurement in a compact form factor, as fluid pressure can be sensed accurately without requiring the deformable member or sensor housing to be large
2Volume of moving object
If metallic strain gauge force sensors are used, then compact size is achieved, but sensitivity is diminished
Solution Approach 1:
The patent introduces a fluid-filled deformable encapsulating member as an intermediary between the applied force and the pressure sensor. This intermediary amplifies the force signal by converting mechanical deformation into fluid pressure changes, which the pressure sensor can detect with high sensitivity, thereby enhancing sensitivity without increasing sensor size
Solution Approach 2:
The patent changes the measurement parameter from direct mechanical strain (as in strain gauges) to fluid pressure. The deformable encapsulating member converts applied force into pressure changes in the enclosed fluid, and the pressure sensor detects these pressure variations with high sensitivity, achieving superior force detection capability in a compact form
3Measurement precision
If conventional force sensors are used in active stylus, then force sensing capability is limited, but power consumption is an issue
Solution Approach 1:
The patent replaces conventional mechanical strain gauge systems with a pressure-based sensing system. The deformable encapsulating member transmits force as fluid pressure, and the pressure sensor (which can be a low-power MEMS device) converts pressure to electrical signals, achieving both improved low-force detection accuracy and reduced power consumption compared to traditional mechanical strain measurement systems
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 provides high sensitivity and low power consumption, enabling effective detection of forces in the range of 0-300 grams, enhancing the accuracy of applications like active styluses and robotic gripping devices.
Implementation Method 1
an external force applied to the encapsulating member will cause a deformation of the encapsulating member and will increase the fluid pressure that is sensed by the pressure sensing surface of the pressure sensor
Implementation Method 2
a pressure sensor (e.g., an absolute pressure sensor) having a pressure sensing surface... outputs a signal indicating a pressure sensed by the pressure sensing surface
Data Source
AI summary
An encapsulated pressure sensor includes a pressure sensor having a pressure sensing surface and a mounting surface. The mounting surface is attached to a mounting substrate. A fluid contacts the pressure sensing surface of the pressure sensor. A deformable encapsulating member is attached to the mounting substrate and encapsulates the pressure sensor and the fluid.