Pressure Sensor Strain Amplification via Neutral Axis Shift
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Solution Overview
Problem
Existing pressure sensors, such as capacitive and piezoelectric ceramic sensors, require high precision in design and assembly, leading to increased costs and limited adoption due to complex structural requirements and high processing accuracy needs.
Innovation Solution
A pressure sensor utilizing a pressure sensitive plate with a thickness of 0.2–3 mm and a low Young's modulus of up to 120 GPa, which amplifies pressure strain signals by shifting the bending neutral axis and enhancing curvature changes, allowing for easier detection of deformations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If capacitive sensors are used to detect pressure through distance changes, then pressure information can be obtained, but high processing accuracy and assembly accuracy are required
Solution Approach 1:
The patent replaces capacitive sensing (which requires precise distance control and high assembly accuracy) with strain gauge sensing on a pressure-sensitive plate. The strain gauges directly measure mechanical deformation, eliminating the need for precise capacitive gap control and complex assembly tolerances while maintaining pressure detection capability
Solution Approach 2:
The patent changes the measurement parameter from capacitive distance change to strain deformation. By using strain gauges that directly measure the deformation of the pressure-sensitive plate, the system achieves pressure measurement without requiring high assembly accuracy, as strain gauges are tolerant to mounting variations
2Measurement precision
If piezoelectric ceramic sensors are used to measure pressure through transient voltage changes, then pressure measurement is achieved, but uniform piezoelectric ceramic pieces are required and special installation methods are needed, greatly increasing cost
Solution Approach 1:
The patent replaces expensive piezoelectric ceramic sensors with inexpensive strain gauge sensors. Strain gauges are much cheaper to manufacture and install, eliminating the need for costly piezoelectric ceramic pieces and special installation procedures, while still providing accurate pressure measurement capability
Solution Approach 2:
The patent substitutes piezoelectric ceramic sensing with strain gauge sensing. This replacement eliminates the need for uniform piezoelectric ceramic pieces and special installation methods, significantly reducing manufacturing cost and simplifying the installation process while maintaining pressure measurement functionality
3Measurement precision
If a pressure sensitive plate with larger thickness is selected, then the bending neutral axis shifts and curvature changes are enhanced, amplifying the strain signal, but the plate becomes less flexible
Solution Approach 1:
The patent optimizes the thickness parameter of the pressure-sensitive plate to achieve signal amplification. By selecting a specific thickness range, the plate's neutral axis shifts sufficiently to amplify strain signals while maintaining adequate flexibility for practical applications, resolving the trade-off between signal amplification and flexibility
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
The solution improves detection sensitivity and reduces the complexity and cost of pressure sensor design, enabling more distinctive deformation detection under the same conditions and facilitating easier installation and wider applicability.
Implementation Method 1
the pressure sensitive plate is made of elastic material having a Young's modulus not larger than 120 GPa
Implementation Method 2
the bending neutral axis of the pressure sensing plate (that is, the zero strain line when the strain changes from positive to negative) is drastically shifted, so that the curvature changes on the pressure sensing plate caused by the bending is enhanced
Implementation Method 3
a deformation may be sensed only when it occurs on the surface directly opposite to the pressing surface, therefore, under the same conditions, the deformation of a thicker pressure sensing plate is more distinctive than the deformation of a thinner pressure sensing plate, thus the deformation caused by pressure is more distinctive as well, the strain signals detected by the strain sensing unit are amplified
Data Source
AI summary
The invention disclosed is a pressure sensor, comprising: a pressure sensing plate and a strain sensing unit which are arranged in a stacked manner, wherein the thickness of the pressure sensing plate is 0.2 3 mm, and the material of the pressure sensing plate is an elastic material with a Young's modulus not greater than 120 GPa. Also disclosed is a display apparatus, comprising a panel, a pressure sensing plate and a strain sensing unit which are arranged in a stacked manner in sequence, wherein the thickness of the pressure sensing plate is 0.2 3 mm, and the material of the pressure sensing plate is an elastic material with a Young's modulus not greater than 120 GPa. Also disclosed is an electronic device comprising the pressure sensor, and an electronic device comprising the display apparatus. The pressure sensor, the display apparatus and the electronic device disclosed can magnify the size of pressure and deformation, so that a pressure deformation signal can be detected using a relatively small pressure, and detection precision is improved.