Ultrasonic Fluidic Device Impedance Control for Standing Wave Stability
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Solution Overview
Problem
Existing fluidic devices that perform acoustic focusing of fine particles in fluids face instability due to temperature changes, which affect the generation of standing waves, making it difficult to maintain consistent particle convergence.
Innovation Solution
A fluidic device with a controller that measures the impedance of an ultrasonic transmission part while changing the drive frequency of the drive signal within a predetermined range, specifies a drive frequency at which impedance is a local maximum, and sets this frequency as the optimal drive frequency for the ultrasonic transmission part, ensuring stable standing wave generation even with temperature changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a standing wave is generated using a fixed drive frequency, then the device structure is simple, but the standing wave generation becomes unstable due to temperature changes
Solution Approach 1:
The patent implements a feedback control mechanism where the controller continuously monitors the drive frequency and adjusts it based on the relationship between frequency and standing wave generation conditions. When temperature changes occur, the system detects the shift in optimal frequency and automatically compensates by adjusting the drive frequency, thereby maintaining stable standing wave generation without requiring complex hardware modifications
Solution Approach 2:
The patent changes the operational parameter (drive frequency) dynamically in response to environmental conditions (temperature changes). By adjusting the drive frequency based on the predetermined relationship between frequency and standing wave generation, the system adapts to temperature variations and maintains reliable particle convergence without increasing device complexity
2Reliability
If the drive frequency is adjusted to compensate for temperature changes, then the standing wave generation stability is improved, but the control complexity increases
Solution Approach 1:
The system performs self-adjustment by automatically modifying the drive frequency in response to temperature changes without requiring external intervention. The controller autonomously monitors conditions and adjusts parameters to maintain optimal standing wave generation, making the system self-regulating and easy to operate while ensuring consistent particle convergence
Solution Approach 2:
The patent establishes a predetermined relationship between drive frequency and standing wave generation conditions before actual operation. This pre-characterization allows the system to quickly determine the appropriate frequency adjustment for given temperature conditions, enabling automatic compensation without complex real-time calculations or user intervention
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 approach allows for stable generation of standing waves and effective particle convergence, enabling consistent separation of fine particles in fluids despite temperature variations, and can be applied to various fluids such as water and blood.
Implementation Method 1
an ultrasonic wave generated by the piezoelectric element is transmitted into the channel via the channel substrate
Implementation Method 2
a standing wave is generated in a fluid in the channel
Implementation Method 3
a piezoelectric element provided at the channel substrate
Implementation Method 4
The controller measures impedance of the ultrasonic transmission part at a time when the ultrasonic transmission part is driven
Data Source
AI summary
A fluidic device includes: a channel that extends along a first axis and through which a fluid flows; an ultrasonic transmission part that is disposed at the channel and transmits an ultrasonic wave into the channel along a second axis orthogonal to the first axis in response to an input of a drive signal; and a controller that controls the ultrasonic transmission part. The controller measures impedance of the ultrasonic transmission part at a time when the ultrasonic transmission part is driven while changing a drive frequency of the drive signal within a predetermined range, specifies a drive frequency at which the impedance is a local maximum and sets the drive frequency at which the impedance is a local maximum as a first drive frequency, and inputs the drive signal of the first drive frequency to the ultrasonic transmission part.