LiDAR Diffractive Structure Angled Window Packaging
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Solution Overview
Problem
Existing LiDAR systems face challenges in compact packaging behind steeply-inclined transparent surfaces due to the need for optical axes to be angled significantly, which complicates the design and increases physical dimensions.
Innovation Solution
The use of diffractive structures, such as gratings, to fold the optical axis and redirect beams through a transparent window at angles greater than 30° relative to the normal, combined with wavelength tuning and scanning mechanisms, allows for compact packaging and efficient scanning across a wide field of view.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If LiDAR systems are mounted behind steeply-inclined transparent surfaces, then packaging efficiency is improved, but optical axis alignment becomes more complex
Solution Approach 1:
A diffractive optical element is introduced as an intermediary component between the LiDAR assembly and the transparent window. This element modifies the optical path to compensate for the angular deviation caused by mounting behind the inclined window, thereby simplifying the overall optical alignment requirements while maintaining compact packaging
Solution Approach 2:
The patent utilizes angular dimension manipulation by mounting the LiDAR assembly at a steep angle (e.g., 45 degrees) relative to the transparent window, and compensates by controlling the exit beam angle to be within 10 degrees of normal. This dimensional transformation allows compact packaging while maintaining simple optical alignment
2Adaptability or versatility
If the optical axis is angled significantly to pass through the transparent window, then mounting flexibility is improved, but beam scanning precision deteriorates
Solution Approach 1:
The patent changes the angular parameters of the optical system by controlling the exit beam angle to be within 10 degrees of normal to the transparent window, while allowing the internal LiDAR assembly to be mounted at steep angles. This parameter transformation maintains mounting flexibility while preserving beam scanning precision
Solution Approach 2:
The diffractive optical element acts as a mediator that decouples the mounting angle from the beam exit angle, allowing the LiDAR assembly to be mounted at flexible steep angles while the diffractive element ensures the exit beams maintain precise angular control within 10 degrees of normal
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 enables compact and efficient depth sensing by allowing LiDAR systems to be mounted behind steeply-inclined surfaces, such as windshields, while ensuring dense coverage of the field of view through angular and wavelength scanning, thereby improving the packaging and operational efficiency of the systems.
Implementation Method 1
A diffractive structure is mounted approximately parallel to the transparent window and positioned to intercept the one or more beams emitted by the LiDAR assembly and turn the beam axis to pass through the transparent window at an angle greater than 30° relative to a normal to a surface of the transparent window
Implementation Method 2
The depth value at each pixel in the depth map is derived from the difference between the emission time of the outgoing pulse and the arrival time of the reflected radiation from the corresponding point in the scene, which is referred to as the 'time of flight' of the optical pulses
Data Source
AI summary
Sensing apparatus includes a transparent window and a LiDAR assembly, including a beam source, which is configured to emit one or more beams of optical radiation along a beam axis, and which is configured to scan the one or more beams over an angular range about the beam axis. A diffractive structure is mounted approximately parallel to the transparent window and positioned to intercept the one or more beams emitted by the LiDAR assembly and turn the beam axis to pass through the transparent window at an angle greater than 30° relative to a normal to a surface of the transparent window.