Piezoelectric Actuator Vibration Control for Charged Particle Beam Stability
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Solution Overview
Problem
Conventional charged particle beam irradiation apparatuses face challenges in suppressing vibrations caused by the movement of a stage, which can alter the beam trajectory and result in a large, heavy, and costly apparatus configuration due to the use of linear motors and their magnetic fields.
Innovation Solution
A compact and simple vibration control system using actuator units with piezoelectric elements that apply forces to counteract the inertial forces generated by the stage movement, maintaining the beam trajectory stability without the need for magnetic fields.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a linear motor is used to suppress vibrations caused by stage movement, then vibration suppression is achieved, but the apparatus becomes large, heavy, and costly due to magnetic field requirements
Solution Approach 1:
The patent replaces the linear motor (electromagnetic system) with a piezoelectric actuator system. The piezoelectric elements convert electrical energy directly to mechanical displacement through the piezoelectric effect, eliminating the need for magnetic fields. This substitution reduces apparatus size and weight while maintaining vibration suppression capability through direct mechanical coupling to the vibration-isolated table.
Solution Approach 2:
The patent extracts and eliminates the magnetic field generation component (linear motor) from the vibration suppression system. By using piezoelectric actuators instead, the system removes the harmful magnetic field that causes beam trajectory deviation, while retaining the essential vibration cancellation function through direct mechanical force application to the table.
2Stability of the object's composition
If a linear motor is used to cancel reaction force, then vibration suppression is achieved, but the apparatus configuration becomes large and heavy
Solution Approach 1:
The patent substitutes the complex linear motor system with a more compact piezoelectric actuator system. The piezoelectric elements can be integrated directly into the table structure, eliminating the need for separate motor assemblies, magnetic field shielding, and associated control infrastructure, thereby simplifying the overall apparatus configuration.
Solution Approach 2:
The piezoelectric elements are integrated within or directly coupled to the table structure, with the actuator units nested into the table's framework. This integration allows the vibration suppression system to be embedded within the existing apparatus structure rather than adding external components, reducing overall complexity.
3Stability of the object's composition
If a linear motor generates force to counteract reaction force, then vibration suppression is achieved, but magnetic field influences alter the charged particle beam trajectory
Solution Approach 1:
The patent replaces the electromagnetic linear motor with a piezoelectric actuator system that generates mechanical force without producing magnetic fields. The piezoelectric elements expand or contract in response to applied voltage, directly transmitting mechanical force to the table through curved plates and connectors, thereby eliminating magnetic field interference with the charged particle beam while maintaining vibration suppression.
Solution Approach 2:
The patent converts the limitation of piezoelectric materials (small displacement) into a benefit by using curved plates that amplify the small piezoelectric displacement into sufficient mechanical force for vibration suppression, while avoiding the harmful magnetic fields of linear motors.
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
Effectively suppresses vibrations in the charged particle beam irradiation apparatus, ensuring high accuracy and stability of the beam trajectory while reducing the apparatus size and manufacturing costs.
Implementation Method 1
a piezoelectric element provided on the curved plate and configured to change a curvature of the curved plate through expansion and contraction that occur due to application of a voltage
Data Source
AI summary
A charged particle beam irradiation apparatus according to an embodiment includes: an optical column; a stage; a mount supporting the stage; a chamber provided on the mount and supporting the optical column; a detector configured to detect movement of the stage; actuator units each including a curved plate, a piezoelectric element, and a connector connected configured to transmit a first force generated by a change of the curvature of the curved plate to the mount; and an actuator control circuit configured to control the voltage applied to the piezoelectric element of each of the actuator units based on movement information, so that the first force is transmitted from the actuator units to the mount against a second force acting on the mount due to the movement of the stage.