Rotatable LiDAR Mirror Coupling for Thermal Expansion Mismatch
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Solution Overview
Problem
Existing LIDAR systems face issues with undesirable deformations and temperature-dependent mismatches in the coefficient of thermal expansion (CTE) between the mirror body and shaft, leading to irregular light direction and reduced scanning accuracy.
Innovation Solution
A rotatable mirror assembly is designed with a multi-sided structure having a different CTE than the shaft, coupled by flexible support members to accommodate thermal expansion, maintaining reflective surface flatness and improving scanning accuracy over a wide angle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a rigid coupling is used between the shaft and mirror body, then structural stability is improved, but thermal expansion mismatch causes deformation and reduces scanning accuracy
Solution Approach 1:
The patent changes the physical parameters of the support members by selecting materials with specific thermal expansion coefficients that match or compensate for the mismatch between the shaft and mirror body. This allows the support members to accommodate thermal expansion differences while maintaining structural stability and scanning accuracy across a wide temperature range.
Solution Approach 2:
The support members act as intermediary elements between the shaft and the mirror body. Rather than directly coupling the two components, the support members mediate the connection, allowing for relative movement and thermal expansion accommodation while maintaining the structural relationship between the shaft and mirror assembly.
2Ease of manufacture
If a single-material construction is used for the shaft and mirror body, then manufacturing simplicity is improved, but thermal expansion mismatch causes irregular light direction
Solution Approach 1:
The patent employs composite material construction where the support members are made from materials with specific thermal expansion properties that differ from both the shaft and mirror body materials. This composite approach allows each component to be manufactured from optimal materials while the assembly as a whole maintains thermal stability and reliable light direction.
3Adaptability or versatility
If the mirror assembly is designed for broad scanning angle, then coverage area is improved, but thermal deformation increases and reduces precision
Solution Approach 1:
The patent addresses thermal deformation in broad-scanning mirror assemblies by changing the thermal parameters of the support members. The support members are designed with material properties that allow them to expand and contract with temperature changes, compensating for thermal deformation and maintaining scanning precision across wide angular ranges and varying temperatures.
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 solution ensures stable and precise light direction over a broad scanning angle, minimizing deformations and maintaining reflective surface flatness, enhancing the LIDAR system's performance and accuracy.
Implementation Method 1
The elastic support members are configured to accommodate a thermal expansion or contraction between the shaft and the rotatable structure
Implementation Method 2
A rotatable mirror assembly is designed with a multi-sided structure having reflective surfaces... configured to rotate so as to direct laser light around an environment
Data Source
AI summary
The present disclosure relates to optical devices and systems, specifically those related to light detection and ranging (LIDAR) systems. An example device includes a shaft defining a rotational axis. The shaft includes a first material having a first coefficient of thermal expansion. The device also includes a rotatable mirror disposed about the shaft. The rotatable mirror includes a multi-sided structure having an exterior surface and an interior surface. The multi-sided structure includes a second material having a second coefficient of thermal expansion. The second coefficient of thermal expansion is different from the first coefficient of thermal expansion. The multi-sided structure also includes a plurality of reflective surfaces disposed on the exterior surface of the multi-sided structure. The multi-sided structure yet further includes one or more support members coupled to the interior surface and the shaft.