Piezoelectric Actuator with Integrated Shear Mode Sensor
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Solution Overview
Problem
There is a demand for a simple actuator that can move an object by a small displacement with high precision, particularly in applications like scanning probe microscopes and semiconductor processing, where precise movement in the range of nanometers to picometers is required, but existing technologies lack effective solutions for precise motion measurement.
Innovation Solution
A piezoelectric actuator is developed, incorporating a position sensor with a piezoelectric element operating in shear mode and a position sensor that measures motion based on input voltages, using a combination of substrates with conductive layers and a driver circuit to adjust voltage magnitudes and phases, allowing for precise measurement of the movable member's position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a piezoelectric actuator is used to achieve small displacement with high precision, then movement precision is improved, but motion measurement capability is insufficient
Solution Approach 1:
The patent combines the piezoelectric element and position sensor into a single integrated actuator unit. The position sensor is disposed between the piezoelectric element and the movable member, allowing the actuator to both generate precise motion and measure its position simultaneously, thereby improving measurement precision and functionality without requiring separate measurement systems.
2Measurement precision
If a position sensor is added to the piezoelectric actuator, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The position sensor is integrated within the existing actuator structure, disposed between the piezoelectric element and movable member, rather than adding external measurement equipment. This merging approach enables position measurement functionality while minimizing additional structural complexity by utilizing the existing spatial arrangement of actuator components.
Solution Approach 2:
The integrated position sensor serves dual purposes: it measures the position of the movable member and also contributes to the overall structural integrity of the actuator assembly. This multi-functionality reduces the need for separate structural and measurement components, thereby limiting the increase in device complexity.
3Measurement precision
If multiple substrates with conductive layers are stacked for the position sensor, then measurement precision is improved, but manufacturing complexity increases
Solution Approach 1:
The position sensor is divided into multiple substrates stacked sequentially, with each substrate containing specific conductive layers for different measurement functions. This segmentation allows each layer to be optimized for its specific function while maintaining overall measurement precision, and enables modular manufacturing processes that can simplify fabrication compared to creating a single complex sensor structure.
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
The piezoelectric actuator achieves precise movement and measurement of the movable member with high accuracy, enabling precise displacement control in nanometer to picometer ranges, addressing the need for precise motion in various industrial applications.
Implementation Method 1
a piezoelectric element that is disposed between the fixed member and the movable member and configured to operate in a shear mode based on input voltages applied to the piezoelectric element and move the movable member relative to the fixed member
Implementation Method 2
a position sensor that is disposed between the piezoelectric element and the movable member and configured to measure a motion of the movable member
Data Source
AI summary
A piezoelectric actuator and a method of measuring a motion by using the piezoelectric actuator are provided. The piezoelectric actuator includes: a movable member that is disposed to face the fixed member; a piezoelectric element that is disposed between the fixed member and the movable member, and configured to operate in a shear mode based on input voltages applied to the piezoelectric element and move the movable member relative to the fixed member; and a position sensor that is disposed between the piezoelectric element and the movable member, and configured to measure a motion of the movable member.