FMCW LIDAR Beam Steering Using Optical Gratings for Road Debris Detection

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Solution Overview

Problem

Current beam steering technologies for LIDAR systems in automotive applications are either mechanically unreliable, costly, or lack the necessary performance standards for semi-autonomous and autonomous vehicles.

Innovation Solution

The implementation of an optical grating array that uses a frequency-modulated continuous-wave (FMCW) pattern to achieve wide-angle beam steering without mechanical motion, leveraging photonic integrated circuitry for cost-effectiveness and high performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If mechanical beam steering is used in LIDAR systems, then beam steering capability is achieved, but reliability deteriorates due to mechanical unreliability

Engineering Contradiction:

Improvebeam steering capabilityVSAvoidmechanical reliability

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The patent replaces mechanical beam steering components with an optical grating array that uses diffraction to steer the laser beam. The grating array consists of multiple gratings with different orientations that can be selectively activated to change beam direction without any moving parts, thereby eliminating mechanical unreliability while maintaining beam steering capability.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The beam steering function is segmented into multiple independent optical gratings, each capable of steering the beam in a specific direction. By selectively activating different gratings based on the desired beam direction, the system achieves flexible beam steering without requiring a single complex mechanical steering mechanism, improving both reliability and operational flexibility.

Inventive Principle:

Principle #1Segmentation

2Measurement precision

If advanced beam steering technologies are implemented, then performance standards are met, but cost increases

Engineering Contradiction:

Improvedetection performanceVSAvoidmanufacturing cost

Core Design Contradiction:

Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent employs optical gratings that can be manufactured using standard semiconductor fabrication processes, making them relatively inexpensive compared to mechanical beam steering components. The gratings are static and have no moving parts, reducing assembly complexity and manufacturing costs while maintaining high detection performance through precise optical diffraction control.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

By replacing expensive mechanical beam steering mechanisms with statically fabricated optical gratings, the system achieves comparable or superior performance at lower cost. The gratings can be integrated into the LIDAR housing using standard manufacturing techniques, eliminating the need for precision mechanical assemblies and reducing overall system cost.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 provides a cost-effective, static, and functional beam steering mechanism that enhances the detection of anomalies on the road, improving the reliability and efficiency of LIDAR systems in automotive applications.

Implementation Method 1

A light that passes through the optical grating can be caused to diffract at an angle that is a function of a wavelength of the light

Methodology Applied

Scientific EffectDiffraction: Diffraction

Implementation Method 2

frequency-modulated continuous-wave (FMCW) pattern for road debris detection

Methodology Applied

Scientific EffectFrequency modulation: Phase Modulation

Implementation Method 3

LIDAR is a detection system that uses light waves to determine the range, angle, and/or velocity of objects

Methodology Applied

Scientific EffectLight reflection: Reflection

Data Source

PatentUS12292511B2Method for road debris detection using low-cost LIDAR

Publication Date: 2025.05.06 TOYOTA JIDOSHA KK

AI summary

Improved systems and methods are provided to implement anomaly detection. The method includes a FMCW LIDAR system that steers the laser beam of the LIDAR system via the wavelength tuning of a FMCW. The direction of the laser beam can be diffracted and controlled by the optical grating antennas which may diffract the laser beam as a function of wavelength. The method may also provide a LIDAR sensor with exhibits a controlled and wide-angle fill or output without the use of conventional mechanical mechanisms for scanning. The LIDAR system provides a cost-effective method to reduce scan dimensionality without sacrificing performance.