Lidar Diffractive Element Multi-Wavelength Beam Steering
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Solution Overview
Problem
Existing LIDAR systems face limitations in angular scanning due to sensitivity to vibrations, inhomogeneous scanning angles, and the need for intermittent observation of directions, requiring a compromise between scanning precision, speed, and amplitude.
Innovation Solution
A LIDAR system that simultaneously emits radiation at multiple distinct wavelengths, using a diffractive optical component to direct the radiation in different directions within the same xz plane, and an optical detection system with photodiodes to generate signals from these wavelengths, allowing for simultaneous observation of multiple directions and robust measurement of radial speed and position without moving parts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If mechanical scanning is used to scan space with an optical beam, then the LIDAR can cover a large area and adjust scanning direction, but the system becomes highly sensitive to vibrations and accelerations
Solution Approach 1:
The patent replaces mechanical scanning systems with a diffractive optical element that uses interference of light waves to steer the beam. Instead of moving mirrors or mechanical components, the system uses phase modulation of light passing through the diffractive element to change beam direction, eliminating mechanical parts and their associated vibration sensitivity.
Solution Approach 2:
The diffractive optical element acts as an intermediary between the laser source and the target scene. It modulates the light waves passing through it to achieve beam steering without direct mechanical movement, using optical interference patterns to redirect light in desired directions while remaining stationary and vibration-resistant.
2Reliability
If interference optical system is used to deflect the optical beam, then the system has no moving parts, but it cannot obtain large angular scan on two axes
Solution Approach 1:
The patent extends the scanning capability from one dimension to two dimensions by using a diffractive optical element with phase modulation capabilities in both horizontal and vertical directions. The element creates interference patterns that can steer the beam across a two-dimensional angular space, overcoming the single-axis limitation of conventional interference systems.
Solution Approach 2:
The system uses dynamic phase modulation of the light waves passing through the diffractive element to achieve large angular scans. By varying the phase distribution across the element, the beam can be steered to different angles without mechanical movement, enabling both wide coverage and fine positioning.
3Area of stationary object
If scanning is performed to observe different directions, then the LIDAR can cover multiple areas, but each direction is observed intermittently rather than continuously
Solution Approach 1:
The patent enables simultaneous observation of multiple directions by using a diffractive optical element that can maintain beam steering to multiple angles at the same time. Unlike sequential scanning that moves the beam from one direction to another, this system can illuminate and detect multiple spatial zones concurrently, providing continuous monitoring of the entire coverage area.
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 simultaneous observation of multiple directions, reducing sensitivity to vibrations and allowing for precise measurement of radial speed and position, overcoming the constraints of existing scanning methods.
Implementation Method 1
a diffractive optical component configured to direct the radiation emitted by the laser source towards the scene to be observed in a different direction for each said wavelength simultaneously
Implementation Method 2
the photodiode(s) generate a signal comprising the beats of the wavelengths of the radiation reflected by the scene to be observed with the radiation at the wavelength λ 0
Implementation Method 3
The principle is then to use an interference optical assembly to direct the light in a given direction in space according to the wavelength. Generally speaking, this involves separating the optical signal into several points and imposing a phase shift between these points. The interference between the signals coming from these points is constructive in a given direction.
Implementation Method 4
an optical system configured to direct onto the photodiode(s) laser radiation emitted by said or another laser source and having a wavelength λ 0 different from said n wavelengths λ i
Data Source
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AI summary
LIDAR system (10) comprising at least one laser source (1) and an optical detection system (6) for detecting a radiation beam emitted by the laser source and reflected by a scene to be observed, characterised in that: - the laser source is suitable for emitting simultaneously at n>1 separate wavelengths λi, i∈[1,n]; - the LIDAR system also comprises a diffractive optical component (2) configured to direct the radiation beam (4) emitted by the laser source to the scene to be observed in a different direction for each said wavelength in a simultaneous manner, the directions being located in the same plane xz; and - the optical detection system comprises at least one photodiode (5) arranged so as to be illuminated by the radiation beam reflected by the scene to be observed, as well as an optical system (7), which is configured to direct a laser radiation beam (3) emitted by said or another laser source and has a wavelength λ0 which is different from said n wavelengths λi, to the one or more photodiodes, such that the one or more photodiodes generate a signal comprising the beats of the wavelengths of the radiation beam reflected by the scene to be observed with the radiation beam having wavelength λ0.