Oscillating Mirror Strain Sensor Isolation via Segmented Beam Design
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Solution Overview
Problem
Existing oscillating mirror elements with strain sensors face issues of excessive stress and unstable output due to the proximity of the strain sensor to the drive portion, leading to reduced scan characteristics and inaccurate displacement detection.
Innovation Solution
The oscillating mirror element design includes a dedicated sensor beam portion for the strain sensor, spaced apart from the drive portion, with a body portion that supports both the mirror and sensor beams, allowing for reduced stress application and improved displacement detection accuracy, while maintaining efficient drive force transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the strain sensor is arranged near the drive portion, then the structure is compact, but excessive stress is applied to the strain sensor causing unstable output
Solution Approach 1:
The base is divided into functionally independent beam portions: a mirror beam portion for supporting the oscillating mirror and a sensor beam portion for supporting the strain sensor. This segmentation allows the strain sensor to be positioned away from the drive portion, reducing stress exposure while maintaining structural integrity.
Solution Approach 2:
The sensor beam portion acts as an intermediary structure that couples the strain sensor to the base while isolating it from excessive stress generated by the drive portion. This intermediate structure enables stable stress detection without direct exposure to drive-induced stress fluctuations.
2Device complexity
If the strain sensor is bonded to the base with adhesive near the drive portion, then the structure is simple, but the adhesive causes attenuation of mirror oscillation
Solution Approach 1:
The base is segmented into separate mirror beam portion and sensor beam portion, allowing the strain sensor to be mounted on the sensor beam portion rather than directly on the mirror beam portion. This reduces adhesive-induced damping on the oscillating mirror while still enabling displacement detection.
Solution Approach 2:
The sensor beam portion is designed as a separate structural element that replicates the mechanical coupling function without directly interfering with the mirror oscillation. The strain sensor on the sensor beam portion detects displacements that are mechanically coupled to the mirror system, enabling indirect measurement with minimal damping.
3Reliability
If the strain sensor is spaced apart from the drive portion, then excessive stress is reduced, but the structure becomes more complex
Solution Approach 1:
The mirror beam portion and sensor beam portion are merged into a single integrated base structure, sharing common support elements. This integration maintains structural simplicity while enabling functional separation that protects the strain sensor from excessive stress.
Solution Approach 2:
The base structure serves multiple functions: supporting the oscillating mirror, mounting the strain sensor, and providing mechanical coupling between components. The unified base design achieves this multi-functionality without requiring additional complex mounting structures.
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 provides a stable output from the strain sensor with reduced energy loss and enhanced scan characteristics, enabling accurate detection of mirror displacement and improved projector performance.
Implementation Method 1
a strain sensor that detects the amount of displacement of the mirror portion
Data Source
AI summary
An oscillating mirror element includes a mirror portion, a drive portion that drives the mirror portion, a strain sensor capable of detecting an amount of displacement of the mirror portion, and a base including a mirror beam portion provided with the mirror portion, a sensor beam portion provided with the strain sensor, and a body portion that supports the mirror beam portion and the sensor beam portion and is provided with the drive portion.