Dual-Axis Piezoelectric Actuator for Optical Scanning
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Solution Overview
Problem
Existing optical scanners that use torsional resonators require two actuators to perform both main and sub-scanning, leading to increased cost and size due to the limited axis of rotation of the mirror.
Innovation Solution
An actuator design that includes a mass portion supported by elastic and beam portions with piezoelectric elements, utilizing a voltage superimposing mechanism to drive the mass portion to rotate about two intersecting axes, allowing for both main and sub-scanning with a single scanner.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single actuator with one pair of spring portions is used, then the device complexity is reduced, but the mirror can only rotate about one axis, requiring two actuators for both main and sub-scanning
Solution Approach 1:
The single actuator is segmented into two independent vibration systems: a first vibration system with a first pair of spring portions for main scanning, and a second vibration system with a second pair of spring portions for sub-scanning. This segmentation allows each system to independently control rotation about a different axis while using a single integrated actuator structure.
Solution Approach 2:
The actuator is designed with multi-functionality by incorporating both the first and second vibration systems within a single device. The first vibration system performs main scanning while the second vibration system performs sub-scanning, allowing one actuator to replace what would traditionally require two separate actuators.
2Adaptability or versatility
If two actuators are used to perform both main and sub-scanning, then the scanning capability is complete, but the cost and size increase
Solution Approach 1:
The patent merges two separate actuator functions into a single integrated actuator structure. The first vibration system (with first pair of spring portions) and the second vibration system (with second pair of spring portions) are combined in one actuator, allowing both main and sub-scanning to be performed by a single device rather than requiring two separate actuators.
3Device complexity
If a single actuator structure is used, then the size is reduced, but the mirror rotation is limited to one axis
Solution Approach 1:
The actuator extends from one-dimensional rotation to two-dimensional rotation by adding the second vibration system. The first vibration system provides rotation about a first axis, while the second vibration system provides rotation about a second axis that intersects the first axis, enabling two-dimensional scanning capability within a single actuator 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
Enables the actuator to rotate about two axes simultaneously, reducing cost and size while maintaining efficient scanning capabilities, and can be applied to optical scanners and image forming apparatuses.
Implementation Method 1
a piezoelectric element bonded on each of the beam portions; voltage applying means that applies voltage to each of the piezoelectric elements so that each of the beam portions is bended to be deformed
Implementation Method 2
a vibrating part having a pair of elastic portions supporting the mass portion
Data Source
AI summary
An actuator includes: a mass portion; a vibrating part having a pair of elastic portions supporting the mass portion; at least one pair of beam portions supporting the vibrating part; a piezoelectric element bonded on each of the beam portions; voltage applying means that applies voltage to each of the piezoelectric elements so that each of the beam portions is bended to be deformed so as to drive the vibrating part, in which the voltage applying means includes: a first voltage generating part that generates first voltage periodically changing with a first frequency; a second voltage generating part that generates second voltage periodically changing with a second frequency different from the first frequency; and a voltage superimposing part that superimposes the first voltage and the second voltage, and in which the voltage superimposed at the voltage superimposing part is applied to each of the piezoelectric elements to allow the mass portion to rotate about the first axis extending along the pair of elastic portions with the first frequency while rotating about the second axis intersecting with the first axis with the second frequency.