Piezoelectric Actuator Thermal Expansion Compensation
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Solution Overview
Problem
Existing optical scanners using twist vibrators in laser printers face issues with thermal expansion, leading to displacement of the reflection mirror and shifting of the rotation center axis, which affects desired scanning characteristics and miniaturization.
Innovation Solution
An actuator design incorporating a movable plate, supporter, and piezoelectric elements that elongate and contract to rotate the movable plate, with elastic members and axial members to maintain the rotation center axis constant, allowing for desired vibration characteristics and miniaturization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a pair of springs is used to link the reflection mirror and fixing frame, then the actuator can be assembled with simple components, but thermal expansion causes the first spring to be displaced from its desired position, reducing deformation due to thermal expansion and shifting the rotation center axis
Solution Approach 1:
The first spring is divided into two separate springs (second spring and third spring), each with distinct functions. The second spring provides the linking function while the third spring specifically compensates for thermal expansion, preventing rotation center axis shift and maintaining manufacturing precision.
2Volume of moving object
If the actuator structure is simplified for miniaturization, then device size is reduced, but thermal expansion influences cannot be effectively countered, affecting vibration characteristics
Solution Approach 1:
The spring system is segmented into multiple specialized springs that work together to counter thermal expansion while maintaining a compact structure. This segmentation allows each spring to be optimized for specific functions, ensuring vibration characteristic stability even in a miniaturized actuator.
Solution Approach 2:
The invention changes the parameters of the spring system by introducing multiple springs with different configurations and material properties. This allows the system to maintain desired vibration characteristics while compensating for thermal expansion effects in a miniaturized design.
3Stress or pressure
If the first spring is allowed to expand freely with thermal expansion, then thermal stress is reduced, but the displacement of the linking portion is hindered by the second spring, causing the first spring to buckle and the reflection mirror to shift
Solution Approach 1:
The spring system is segmented into multiple specialized springs that work together to counter thermal expansion while maintaining a compact structure. This segmentation allows each spring to be optimized for specific functions, ensuring vibration characteristic stability even in a miniaturized actuator.
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 actuator effectively reduces the impact of environmental temperature on the optical scanner, maintaining desired scanning characteristics and enabling miniaturization while ensuring stable rotation center axis alignment.
Implementation Method 1
a piezoelectric element to rotate the movable plate. The piezoelectric element elongated and contracted by an energization twists the pair of linking portions to rotate the movable plate
Implementation Method 2
each returned portion include a pair of elastic members that has an elongation shape and be capable of being elastically deformed
Implementation Method 3
Each of the pair of the linking portions includes an axial member extending from the movable plate and a returned portion that links the axial member and the supporter, and is formed so as to return to a side adjacent to the movable plate
Data Source
AI summary
An actuator, includes: a movable plate; a supporter to support the movable plate; a pair of linking portions to link the movable plate and the supporter so as to allow the movable plate to rotate relative to the supporter; and a piezoelectric element to rotate the movable plate. The piezoelectric element elongated and contracted by an energization twists the pair of linking portions to rotate the movable plate, and each of the pair of the linking portions includes an axial member extending from the movable plate and a returned portion that links the axial member and the supporter and is formed so as to return to a side adjacent to the movable plate.