Piezoelectric Actuator Driving Device with Fault Isolation
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Solution Overview
Problem
Current piezoelectric actuators in semiconductor exposure apparatuses face challenges with insulation failure and short circuits due to wire migration, leading to system downtime and high replacement costs when a single actuator fails, as existing solutions are not suitable for maintaining precision positioning.
Innovation Solution
A driving device with a laminated piezoelectric actuator configuration that includes multiple units arranged in series, equipped with a failure detection system and switches to isolate faulty units from the driving circuit, allowing continuous operation by routing current to functional units.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If wire connection is used to apply voltage to piezoelectric ceramics in a laminated actuator, then the actuator can be driven, but insulation performance degrades due to wire migration causing short circuits
Solution Approach 1:
The patent extracts and removes the wire connection component from the system by adopting a wireless voltage application method. This eliminates the source of wire migration and insulation degradation, directly resolving the technical contradiction between maintaining insulation performance and preventing wire migration.
Solution Approach 2:
The patent replaces the mechanical wire connection system with an electrical field-based voltage application method. By using electric fields to apply voltage directly to the piezoelectric ceramics without physical wire contact, the system eliminates wire migration while maintaining actuator drive capability.
2Reliability
If a single piezoelectric actuator is used for positioning, then the structure is simple, but the system stops operation when the actuator fails
Solution Approach 1:
The patent segments the single piezoelectric actuator into multiple independent laminated units that can operate independently. Each unit has its own voltage application electrodes, allowing individual units to be activated or deactivated based on their operational status, thereby enabling continuous system operation even when some units fail.
Solution Approach 2:
The patent changes the operational parameter from a single actuator mode to a multi-unit selective activation mode. By controlling which laminated units are active through selective voltage application, the system can maintain positioning functionality with reduced capacity rather than complete failure, improving reliability without requiring a completely different structural approach.
3Reliability
If wire connection is used for voltage application, then the actuator can be driven, but failure occurs in wire connection leading to loss of function
Solution Approach 1:
The patent extracts and eliminates the wire connection component entirely by implementing a wireless voltage application system. This removes the source of connection failures while preserving the actuator's drive capability through direct electrical field application to the piezoelectric ceramics.
Solution Approach 2:
The patent introduces an intermediary electrical field mechanism to transfer voltage from the voltage application electrodes to the piezoelectric ceramics without direct wire contact. This intermediary field-based transmission method eliminates wire connection failures while maintaining effective voltage application for actuator operation.
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 continuous operation of the apparatus by isolating faulty laminated units, reducing the likelihood of complete system failure and increasing reliability, as the probability of overall failure decreases with the division of units, thus minimizing downtime and maintenance costs.
Implementation Method 1
a laminated piezoelectric actuator which has a plurality of laminated units arranged in series
Data Source
AI summary
A driving device includes a plurality of laminated units formed by alternately stacking piezoelectric element layers and electrode layers, a failure detecting unit configured to detect failure of the laminated units, a plurality of switches provided corresponding to the laminated units and configured to enable and disable current supply to the laminated units, and a driving circuit configured to supply a current for driving to a normal laminated unit of the laminated units, on the basis of an output from the failure detecting unit.