Piezoelectric Droplet Ejecting Head Residual Oscillation Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing droplet ejecting heads with piezoelectric actuators face challenges in increasing ejecting speed without unintended solution dispensing, leading to inaccurate target dropping amounts due to residual pressure oscillations.
Innovation Solution
The droplet ejecting head employs a specific electrical signal waveform that changes voltage levels to control pressure chamber volume, synchronizing with the natural oscillation period of the actuator to ensure complete ejection and prevent residual oscillations, using a waveform that transitions from a first voltage to a second, then a third voltage, and back to the first, to accurately control the ejection process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the ejecting speed is increased by controlling pressure changes in the pressure chamber, then the productivity is improved, but residual pressure oscillations cause unintended solution dispensing and reduce manufacturing precision
Solution Approach 1:
The patent applies periodic action by controlling the piezoelectric actuator to change pressure in the pressure chamber in a periodic manner synchronized with the natural oscillation period of the actuator. The drive circuit changes voltage levels at specific time points corresponding to the oscillation period, creating controlled periodic pressure changes that ensure complete droplet ejection while preventing residual oscillations and unintended dispensing.
Solution Approach 2:
The patent implements feedback control by using a drive circuit that monitors and responds to the oscillation state of the piezoelectric actuator. The circuit changes voltage levels based on the natural oscillation period, adjusting the pressure control timing to eliminate residual oscillations and ensure precise droplet ejection, thereby maintaining dispensing accuracy at high ejecting speeds.
2Device complexity
If a simple voltage control signal is used for the actuator, then the device complexity is reduced, but the reliability of precise droplet ejection is compromised due to residual oscillations
Solution Approach 1:
The patent uses periodic action in the control signal by applying voltage level changes that coincide with the natural oscillation period of the piezoelectric actuator. The drive circuit transitions between first, second, and third voltage levels at time points corresponding to the oscillation period, creating a periodic control pattern that ensures reliable and complete droplet ejection without introducing excessive device complexity.
Solution Approach 2:
The patent applies parameter changes by dynamically adjusting the voltage level parameters of the control signal. The drive circuit changes the voltage from a first level to a second level and then to a third level at specific time points during the oscillation period, optimizing the pressure control parameters to achieve reliable droplet ejection while maintaining manageable device complexity.
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 accurate and efficient dispensing of target solution amounts at higher speeds, preventing unintended ejections and ensuring precise droplet control, thereby improving the reliability and speed of fluid dispensing in biological and pharmaceutical applications.
Implementation Method 1
The actuator may be a piezoelectric actuator that has a structure having a nozzle that ejects droplets
Implementation Method 2
the time period being equal to a primary natural oscillation period of the actuator when the pressure chamber and the nozzle are filled with solution
Data Source
AI summary
A droplet ejecting head includes a board, a pressure chamber, a nozzle, and an actuator configured to cause a pressure change in the pressure chamber in response to an electrical signal supplied from a drive circuit. The drive circuit is configured to set the electrical signal at a first voltage level, change the electrical signal to a second voltage level, set the electrical signal to a third voltage level during a time period after changing the electrical signal from the first voltage level to the second voltage level, the time period being equal to a primary natural oscillation period of the actuator when the pressure chamber and the nozzle are filled with solution, and set the electrical signal to the first voltage level after the time period has elapsed. The third voltage level is between the first and second voltage levels or equal to the second voltage level.