Diffractive Optics in Rotating LiDAR for High-Resolution Scanning

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Solution Overview

Problem

Current lidar systems require complex mechanisms to pivot the laser beam for horizontal and vertical scanning, increasing cost and installation difficulty, and existing systems using diffractive optical elements do not efficiently utilize the laser beam for high-resolution object detection.

Innovation Solution

A lidar unit with a diffractive optical element that splits the laser beam into a one-dimensional vector, allowing for scanning by rotating the housing along a non-orthogonal axis, and uses corresponding matrix patterns to emit and receive laser light spots for accurate time-of-flight analysis, reducing the need for additional scanning mechanisms.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If complex mechanisms such as microlenses or mirrors are used to pivot the laser beam for scanning, then the scanning function is achieved, but the device complexity and cost increase

Engineering Contradiction:
Improvescanning functionVSAvoidcomplexity of scanning mechanisms
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent replaces mechanical scanning mechanisms (microlenses, mirrors) with a diffractive optical element that uses optical diffraction to achieve beam steering. The DOE splits the laser beam into multiple beams through diffraction, eliminating the need for complex mechanical pivoting components while maintaining the scanning function.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent segments the single laser beam into multiple beams using the diffractive optical element. By dividing the beam into several parallel beams, the system achieves scanning capability without requiring complex mechanical mechanisms, as each diffracted beam can be independently directed.

Inventive Principle:
Principle #1Segmentation

2Measurement precision

If multiple laser emitters are used to achieve high resolution, then the detection precision improves, but the manufacturing cost and installation difficulty increase

Engineering Contradiction:
Improvedetection resolutionVSAvoidmanufacturing cost and installation difficulty
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent uses a single laser emitter and segments its output beam into multiple beams through the diffractive optical element. This approach achieves the effect of multiple emitters (improved detection precision) while using only one laser source, thereby reducing manufacturing cost and installation complexity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The diffractive optical element creates multiple copies of the laser beam through diffraction. Each diffracted beam is a copy of the original beam, allowing the system to simulate multiple emitters using a single physical laser source, thus reducing cost while maintaining precision.

Inventive Principle:
Principle #26Copying

3Ease of operation

If the axis of rotation is orthogonal to the beam splitting direction, then the scanning geometry is simplified, but the surface coverage efficiency decreases

Engineering Contradiction:
Improvescanning geometryVSAvoidsurface coverage efficiency
Core Design Contradiction:
Ease of operationVSProductivity

Solution Approach 1:

The patent employs a non-orthogonal arrangement where the rotation axis is intentionally angled relative to the beam splitting direction. This asymmetric configuration optimizes surface coverage efficiency by allowing the laser vectors to sweep across the target surface more effectively, improving productivity while maintaining manageable scanning geometry.

Inventive Principle:
Principle #4Asymmetry

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

Enables efficient, high-resolution object detection with reduced complexity and cost by eliminating the need for additional scanning mechanisms and optimizing laser light distribution for improved detection and evaluation.

Implementation Method 1

the first optic is configured to split the laser light along a second spatial direction

Methodology Applied
Scientific EffectDiffraction: Diffraction

Implementation Method 2

a laser light source (2), adapted to emit laser light (6a) along a first spatial direction (100)

Methodology Applied
Scientific EffectLaser: Laser

Implementation Method 3

the housing (10) is rotatable about an axis of rotation so that the laser light can be pivoted along a third spatial direction

Methodology Applied
Scientific EffectRotation:

Data Source

PatentEP4253998B1Lidar unit with diffractive optical element
Publication Date: 2026.01.28 ROBERT BOSCH GMBH
  • EP4253998B1 patent drawingFigure 1
  • EP4253998B1 patent drawingFigure 2~3

AI summary

The present invention comprises a lidar unit 1 having a laser light source 2, a receiving unit 3, a first optic 4, and a housing 10, wherein the laser light source 2 is arranged to emit a laser light 6a along a first spatial direction 100, the first optic 4 and the laser light source 2 are arranged in the housing 10 such that the laser light 6b is guided to the first optic 4 before leaving the housing 10, the receiving unit 3 is arranged to receive and evaluate the laser light 6c, the first optic 4 is arranged to split the laser light 6b along a second spatial direction 200, the second spatial direction 200 is not identical to the first spatial direction 100, the housing 10 is rotatable about an axis of rotation 300 so that the laser light 6c is pivotable along a third spatial direction 400, the third spatial direction 400 is not identical to the second spatial direction 200 and/or the axis of rotation 300 is not orthogonal to the second spatial direction 200, the first optic 4 is designed as a diffractive optical element, and the first optic 4 has a first matrix pattern 4a.