Tiltable Grating Out-Coupler for LIDAR Alignment

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Solution Overview

Problem

Aligning MEMS mirrors in LIDAR systems is challenging, leading to high interference and poor signal-to-noise ratios due to difficulties in properly aligning the mirrors for steering laser beams.

Innovation Solution

A grating out-coupler assembly with a tiltable surface suspended above a substrate, actuated to control the pitch of the surface, and a grating out-coupler supported by this surface, optically coupled to a photonic circuit, allowing for adjustable orientation and reduced alignment errors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a MEMS mirror is used to steer laser beams, then the LIDAR system can measure the range of objects, but proper alignment becomes difficult resulting in high interference and poor signal-to-noise ratio

Engineering Contradiction:
Improvesignal-to-noise ratioVSAvoidalignment difficulty
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The grating out-coupler is made tiltable through a suspension mechanism with actuators that can dynamically adjust its pitch angle. This dynamic adjustment capability allows the system to optimize alignment after fabrication and compensate for manufacturing tolerances, thereby improving signal-to-noise ratio without requiring extremely precise initial alignment

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The pitch angle of the grating out-coupler is changed as a可调 parameter to optimize system performance. By varying the pitch angle through actuator control, the system can achieve proper alignment conditions and maximize the signal-to-noise ratio, resolving the alignment difficulty issue

Inventive Principle:
Principle #35Parameter changes

2Loss of energy

If the grating out-coupler is fixed on the substrate, then the structure is simple, but alignment errors cannot be corrected leading to optical losses

Engineering Contradiction:
Improveoptical lossVSAvoidassembly structure
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The grating out-coupler is mounted on a tiltable surface with pitch control capability, transforming it from a fixed component to a dynamically adjustable one. This allows correction of alignment errors to minimize optical losses while the suspension and actuator mechanisms add necessary complexity to achieve this correction capability

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

A suspension mechanism acts as an intermediary between the substrate and the grating out-coupler. This intermediary layer provides the degrees of freedom needed for pitch adjustment while maintaining electrical and mechanical connections, enabling alignment correction without direct rigid mounting

Inventive Principle:
Principle #24Intermediary (Mediator)

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 solution improves signal-to-noise ratios and reduces optical losses by maintaining phase relationships across the signal, enhancing the resolution and accuracy of LIDAR systems.

Implementation Method 1

an actuator configured to selectively control a pitch of the tiltable surface

Methodology Applied
Scientific EffectMEMS actuation: Microelectromechanical Systems

Implementation Method 2

a grating out-coupler supported by the tiltable surface, optically coupled to a photonic circuit

Methodology Applied
Scientific EffectOptical coupling: Waveguide (optics)

Data Source

PatentEP3171198B1Systems and methods for tiltable grating out-couplers
Publication Date: 2020.06.10 THE BOEING CO
  • EP3171198B1 patent drawingFigure 1
  • EP3171198B1 patent drawingFigure 2
  • EP3171198B1 patent drawingFigure 3

AI summary

A grating out-coupler assembly is provided. The grating out-coupler assembly includes a substrate 110, a tiltable surface 104 suspended above the substrate 110, an actuator configured to selectively control a pitch of the tiltable surface 104, and a grating out-coupler supported by the tiltable surface 104.