Diffractive Optical Element Lidar Assembly for Compact Eye-Safe Design
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Solution Overview
Problem
Current LIDAR devices face challenges with eye safety, susceptibility to interruptions, and high manufacturing costs due to the use of micro-scanners with small mirror diameters, which limit the receiving aperture and require large detector surfaces for optimal signal detection.
Innovation Solution
An optical assembly utilizing a diffractive optical element, such as a hologram or diffraction grating, to deflect and bundle incoming light waves onto a smaller detector surface, reducing the need for large lens elements and enabling a more compact and cost-effective design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If micro-scanners with small mirror diameters are used, then the overall dimensions are reduced and the system is more compact, but the receiving aperture is limited and eye safety is compromised
Solution Approach 1:
The patent replaces the mechanical scanning system (rotating mirrors) with a fixed optical system using diffractive optical elements. The microlens array and diffraction grating work together to provide beam deflection without moving parts, eliminating the need for large rotating mirrors while maintaining eye safety through a larger effective aperture.
Solution Approach 2:
The patent uses a two-dimensional array of microlenses corresponding to a two-dimensional array of detector elements. This spatial arrangement in multiple dimensions allows the system to achieve large effective aperture area without requiring large individual mirror diameters, thus maintaining compactness while improving eye safety.
2Volume of moving object
If micro-scanners with small mirror diameters are used, then the system is more compact, but the system becomes susceptible to interruptions like rain or dust
Solution Approach 1:
By replacing the mechanical rotating mirror system with a static optical system comprising microlenses and diffraction gratings, the patent eliminates moving parts that are vulnerable to environmental interruptions. The fixed optical paths with multiple parallel channels maintain reliability in adverse conditions while keeping the system compact.
3Reliability
If complex receiving optics are used, then the light collection capability is improved, but a large surface detector is required which increases manufacturing costs
Solution Approach 1:
The patent divides the receiving optics into multiple independent channels, each with a microlens and corresponding detector element. This segmentation allows the use of many small, inexpensive detector elements instead of one large expensive detector, while collectively achieving the same light collection capability through parallel processing of light from different angular directions.
Solution Approach 2:
The patent maps the angular distribution of incoming light in two dimensions onto a two-dimensional detector array. Each detector element receives light from a specific angular range, and the collective array covers the full angular space. This dimensional mapping enables the use of small detector elements arranged in a 2D pattern rather than requiring a single large detector surface.
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 allows for a smaller detector surface while maintaining effective light collection and signal detection, reducing manufacturing costs and improving eye safety by using diffractive optical elements to focus and deflect light waves efficiently.
Implementation Method 1
at least one diffractive optical element with a planar extension is situated between the receiving optical system and the detector, and the at least one diffractive optical element includes a surface with a surface structure with at least one optical function
Data Source
AI summary
An optical assembly, for receiving light waves, includes a receiving optical system for focusing at least one incoming light wave onto a surface of a detector for detecting the at least one light wave, at least one diffractive optical element with a planar extension being situated between the receiving optical system and the detector, and the at least one diffractive optical element including a surface with a surface structure with at least one optical function. Furthermore, a LIDAR device includes an optical assembly of this type.