Rotatable Mirror Assembly With Flexible Mounting For LIDAR

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Solution Overview

Problem

Optical scanning systems, such as LIDAR, face challenges with rotating mirrors that are affected by inertial forces and thermal changes, leading to potential deformation and loss of reflective properties due to rigid coupling methods.

Innovation Solution

A rotatable mirror assembly with a housing and reflective surfaces coupled in a non-rigid manner, allowing limited freedom of movement to accommodate thermal expansion and external forces, using female and male coupling parts or springs to maintain reflective geometry while minimizing mass and strain.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If rigid coupling methods are used to attach reflective surfaces to the housing, then structural stability is improved, but thermal expansion causes deformation and loss of reflective properties

Engineering Contradiction:

Improvestructural stabilityVSAvoidreflective properties

Core Design Contradiction:

Stability of the object's compositionVSManufacturing precision

Solution Approach 1:

The patent uses flexible mounting structures (such as elastic elements, flexible clips, or compliant mechanisms) to couple the reflective surfaces to the housing. These flexible connections allow the reflective surfaces to move slightly with thermal expansion while maintaining their attached state, preventing both detachment and excessive deformation that would occur with rigid coupling.

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The patent employs materials or structures with variable mechanical properties that can adapt to thermal changes. For example, using materials with different thermal expansion coefficients or structures that change stiffness with temperature allow the coupling to remain stable across temperature ranges, accommodating expansion without causing deformation of the reflective surfaces.

Inventive Principle:

Principle #35Parameter changes

2Weight of moving object

If lightweight materials are used for the mirror assembly, then mass is reduced, but tolerance to external inertial forces and environmental changes decreases

Engineering Contradiction:

ImprovemassVSAvoidtolerance to external forces

Core Design Contradiction:

Weight of moving objectVSReliability

Solution Approach 1:

The patent employs composite material structures that combine lightweight materials (such as aluminum alloys, carbon fiber reinforced polymers, or titanium) with sufficient mechanical strength and thermal stability. These composite structures achieve low mass while maintaining the necessary rigidity and environmental tolerance for reliable operation under external inertial forces and temperature variations.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent designs the mirror assembly with dynamic characteristics that allow it to respond to external forces. This may include flexible mounting structures that can absorb inertial forces, damping elements that reduce vibration, or structures that maintain their functional geometry despite dynamic loading, thereby achieving reliability without requiring excessive mass.

Inventive Principle:

Principle #15Dynamics

3Adaptability or versatility

If reflective surfaces are allowed freedom of movement to accommodate thermal expansion, then environmental tolerance is improved, but structural stability deteriorates

Engineering Contradiction:

Improveenvironmental toleranceVSAvoidstructural stability

Core Design Contradiction:

Adaptability or versatilityVSStability of the object's composition

Solution Approach 1:

The patent employs flexible mounting structures (such as elastic elements, flexible clips, or compliant mechanisms) to couple the reflective surfaces to the housing. These flexible connections allow the reflective surfaces to move slightly with thermal expansion while maintaining their attached state, preventing both detachment and excessive deformation that would occur with rigid coupling.

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

Inventive Principle:

Principle #15Dynamics

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 provides a lightweight, environmentally tolerant mirror assembly that maintains reflective properties and stability under varying conditions, reducing the risk of deformation and improving performance in applications like autonomous vehicles.

Implementation Method 1

the reflective surfaces may experience thermal expansion based on changes in the ambient temperature, which may crack or deform the mirror depending on the construction of the mirror assembly

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentUS11536809B1Rotatable mirror assemblies

Publication Date: 2022.12.27 WAYMO LLC

AI summary

Rotatable mirror assemblies and light detection and ranging systems containing rotatable mirror assemblies are described herein. An example rotatable mirror assembly may include (1) a housing having a top end, a bottom end, and a longitudinal axis intersecting the top and bottom ends, and (2) a set of reflective surfaces, where each reflective surface in the set is coupled to the top end of the housing and the bottom end of the housing such that each reflective surface possesses limited freedom of movement with respect to the housing.