Metal Mirror Optical Deflector for LiDAR Vibration Resistance
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Solution Overview
Problem
Conventional LiDAR devices face challenges in securely mounting glass reflectors on rotatable members, balancing securing force with mirror flatness, which affects reliability against vibrations and impacts, especially when used as vehicle components.
Innovation Solution
An optical deflector with a metal-based mirror having reflective surfaces parallel to the rotating shaft, where the mirror is held using a jig with specific reference and contact surfaces to apply forces in multiple directions during cutting, ensuring secure attachment without deforming the mirror surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a glass reflector is firmly secured to a rotatable member with great securing force, then the reliability against vibration and impact is improved, but the mirror surface flatness deteriorates due to deformation
Solution Approach 1:
The patent changes the material parameter from glass to metal (aluminum alloy), which fundamentally alters the mechanical properties. Metal mirrors can be firmly secured with great securing force while maintaining surface flatness due to the material's higher strength-to-weight ratio and structural integrity, resolving the contradiction between reliability and manufacturing precision
Solution Approach 2:
The patent employs a composite structure consisting of a metal base material (aluminum alloy) combined with a reflective coating layer. This composite approach provides both the structural strength needed for firm securing against vibration and impact, and the optical properties required for maintaining mirror surface flatness and reflectivity
2Manufacturing precision
If a glass reflector is not firmly secured to keep mirror surface flatness, then the mirror surface flatness is maintained, but the reflector may be loosened by external vibration and impact
Solution Approach 1:
Changing the material from glass to metal allows for firm securing without surface deformation. The metal material's superior mechanical properties enable strong bonding forces that prevent loosening under vibration and impact while maintaining the mirror surface flatness through the material's structural rigidity
3Area of stationary object
If the mirror length is increased to improve optical performance, then the reflective surface area is increased, but the weight of the rotor increases affecting bearing durability
Solution Approach 1:
The patent changes the material density parameter by using aluminum alloy instead of glass. This allows the mirror to have a larger reflective surface area while maintaining lower weight, as aluminum alloy has approximately one-third the density of glass, thereby improving thrust bearing durability without compromising optical performance
Solution Approach 2:
The composite structure of metal base material with reflective coating enables large surface area mirrors to be constructed with optimized weight characteristics. The lightweight metal substrate provides sufficient structural support for large-area mirrors while minimizing rotor weight, thus protecting the thrust bearing from excessive load
Data Source
AI summary
An optical deflector includes a mirror rotatable around a rotating shaft of the optical deflector, the mirror including a base made of metal and a reflective surface, the reflective surface being parallel to an axial direction of the rotating shaft of the mirror. The mirror has a length that is twice a length from a center of the rotating shaft to the reflective surface, which is shorter than a length of the reflective surface in the direction of the rotating shaft.