Micro Viscometer Using Segmented Thin Film Resonators
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Solution Overview
Problem
Existing viscometers face limitations in measuring viscosity accurately with small fluid volumes, particularly for gases, due to large size requirements and high error margins, and are restricted to low frequency measurements, making them unsuitable for liquids and gases with limited frequency applicability.
Innovation Solution
A micro viscometer design featuring a substrate with two chambers and a thin film, including actuating and sensing parts with piezoelectric layers, and a trench structure for electrical separation, allowing for precise viscosity measurement using resonant frequency analysis and capable of operating with minimal fluid volumes, including gases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a traditional viscometer design (Greenspan viscometer) is used, then gas viscosity measurement is enabled, but the device takes up much space and has high error margin (38% error)
Solution Approach 1:
The device is segmented into two separate chambers (first chamber and second chamber) connected by a narrow channel, allowing independent optimization of each chamber's function while maintaining compact overall size. This segmentation enables precise measurement with reduced fluid volume requirements.
Solution Approach 2:
The invention transitions from traditional large-scale 3D viscometer design to a micro-scale planar configuration using thin films and narrow channels. This dimensional scaling reduces the device volume significantly while maintaining measurement functionality through carefully designed micro-structures.
2Adaptability or versatility
If Helmholtz Resonator is applied for viscosity measurement, then gas viscosity can be measured, but the valid frequency section is limited only to low frequency domain (under 200 Hz)
Solution Approach 1:
The invention changes the operating parameters by designing the chamber volumes, channel dimensions, and thin film properties to support resonance at higher frequencies. By adjusting these physical parameters, the device extends its valid frequency range beyond the traditional low-frequency limitation while maintaining measurement accuracy through resonant frequency analysis.
3Adaptability or versatility
If crystal resonant sensor is used for viscosity measurement, then small quantity of reagent can be measured, but measurements are restricted to liquids and cannot measure gas viscosity
Solution Approach 1:
The device is designed with universal functionality to measure both liquid and gas viscosity using the same fundamental principle of resonant frequency analysis. The chamber-pressure sensor configuration can accommodate different fluid types without requiring separate measurement systems, achieving multi-functionality while maintaining compact size and low fluid volume requirements.
4Measurement precision
If capillary tube viscometer is used, then viscosity measurement is enabled, but large amount of liquid is required (dozen to hundreds of ml)
Solution Approach 1:
The measurement system is segmented into micro-scale chambers and channels that require minimal fluid volume. The narrow channel connecting the chambers creates sufficient flow resistance and pressure differential for accurate viscosity measurement using only microliter quantities of liquid, eliminating the need for large volumes required by traditional capillary tube viscometers.
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
Enables accurate viscosity measurement across a broader frequency domain, reducing error margins and accommodating both liquids and gases with minimal fluid requirements, while maintaining a compact size, thus overcoming the limitations of previous viscometer designs.
Implementation Method 1
an actuating part that disposed on the thin film corresponding to the first chamber; and a sensing part that disposed on the thin film corresponding to the second chamber, wherein at least one main trench is formed in between the first chamber and the second chamber
Implementation Method 2
a sensing part that disposed on the thin film corresponding to the second chamber
Implementation Method 3
Enables accurate viscosity measurement across a broader frequency domain
Implementation Method 4
power loss occurs that cause damping in the crystal resonant frequency
Data Source
AI summary
Disclosed is a micro viscometer comprising a substrate having a first chamber and a second chamber that are positioned at intervals; a thin film disposed on the substrate to cover the first chamber and the second chamber; an actuating part that disposed on the thin film corresponding to the first chamber; and a sensing part that disposed on the thin film corresponding to the second chamber, wherein at least one main trench is formed in between the first chamber and the second chamber.