Actuator with Zigzag Drive Beam for Crosstalk Suppression
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Solution Overview
Problem
Optical scanning devices experience mechanical crosstalk due to resonance frequency variations and manufacturing variations, leading to deteriorated light quality and scanning accuracy.
Innovation Solution
The implementation of a zigzag-shaped bellows structure for vertical drive beams with weighted turn portions and additional ribs on the back surfaces of the vertical drive beams to suppress oscillations and maintain resonance frequency stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a rib is added on the outer driving portion to cause twisting oscillation, then scanning locus stability is improved, but device complexity increases
Solution Approach 1:
The drive beam is divided into multiple segments (first drive beam and second drive beam) that can oscillate independently around different axes. This segmentation allows each beam to be optimized for its specific function while reducing unwanted coupling effects, thereby maintaining scanning stability without requiring additional complex structural elements like ribs.
Solution Approach 2:
The patent introduces orthogonal oscillation dimensions by using two drive beams perpendicular to each other. The first drive beam oscillates around the first axis while the second drive beam oscillates around the second axis orthogonal to the first. This dimensional separation prevents mechanical crosstalk and maintains scanning locus stability without increasing structural complexity in a single dimension.
2Reliability
If the Young's modulus of MEMS structure changes due to temperature change, then resonance frequency stability deteriorates, but material selection flexibility improves
Solution Approach 1:
The patent employs counteracting drive beams where the first drive beam and second drive beam are positioned and configured to compensate for each other's thermal expansion and modulus changes. When temperature changes affect the Young's modulus, the orthogonal arrangement and coupled oscillation modes create counterbalancing effects that stabilize the overall resonance frequency and scanning performance.
Solution Approach 2:
The patent designs the drive beams with specific geometric parameters and material properties that are optimized to minimize thermal sensitivity. By carefully selecting the dimensions, shapes, and material characteristics of the orthogonal drive beams, the system maintains stable resonance frequency across temperature variations while allowing flexibility in material selection for different application requirements.
3Reliability
If horizontal drive beam oscillation propagates to vertical drive beam, then mechanical crosstalk occurs, but energy utilization improves
Solution Approach 1:
The patent introduces asymmetry in the coupling between drive beams by positioning ribs at specific locations on the drive beams. The ribs are placed asymmetrically relative to the oscillation axes, creating different coupling strengths for horizontal and vertical modes. This asymmetric design allows selective suppression of unwanted crosstalk while maintaining efficient energy transfer in the desired oscillation direction.
Solution Approach 2:
The patent uses identical or symmetric structures for the first and second drive beams, allowing the system to benefit from manufacturing consistency and predictable behavior. By copying the successful design of one drive beam to the other, the system achieves stable orthogonal oscillation with minimal crosstalk while maintaining efficient energy utilization through proven geometric and material configurations.
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
This configuration effectively reduces mechanical crosstalk and ringing oscillations, maintaining light quality and scanning accuracy even with resonance frequency variations and manufacturing changes.
Implementation Method 1
a first drive source (151A, 151B) being formed on a front surface of the first drive beam; a second drive source (171A,171B) being formed on a front surface of the second drive beam
Data Source
AI summary
An actuator includes: a first drive beam provided to swing and drive a target object around a first axis and having a first drive source on a front surface; a second drive beam that has a zigzag shape, in which a plurality of beams extending in a direction vertical to a second axis orthogonal to the first axis are included and in which end portions of the beams adjacent with each other are connected at turn portions, and that is provided to swing and drive the object around the second axis, and having a second drive source on a front surface; a fixed frame connected to and support the second drive beam; and a rib formed on a back surface of the second drive beam and at a position away from a connection position of the beams with the turn portions toward the second axis.