Wedge Array Corrects LIDAR Spot Shading and Aberrations
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Solution Overview
Problem
Conventional LIDAR devices experience spot shading and aberrations due to differently sized areas of the transmission signal being deflected into the aperture of the transceiver lens, leading to gaps in the target distance between adjacent spots, especially at scanning angles, resulting in inefficient utilization of the field angle and reduced scanning accuracy.
Innovation Solution
The integration of a wedge array with a lens array in the optical system, where the wedge array is situated upstream or downstream of the lens array, deflects the beams to prevent spot shading and aberrations, ensuring the entire field angle is utilized without spot sections, and maintaining the exit angle unchanged, using wedge elements with varying angles and orientations to correct beam paths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If beam expansion is performed using microlens elements at a distance from the optical axis, then the system robustness against contamination and eye safety are improved, but spot shading and gaps appear in the target distance between adjacent spots
Solution Approach 1:
A wedge array is introduced as an intermediary optical element between the microlens array and the transceiver lens. The wedge array deflects the expanded beams back toward the optical axis, ensuring they properly reach the scanning area. This mediator resolves the contradiction by maintaining the beam expansion benefits while correcting the spot shading effect through controlled deflection.
Solution Approach 2:
The wedge array changes the propagation direction parameter of the beams by introducing controlled angular deviations. By varying the wedge angles across the array, the system adjusts the beam paths to compensate for the spot shading effect, ensuring uniform spot distribution in the target distance while maintaining the expanded beam configuration for robustness and safety.
2Area of stationary object
If the field angle of the lens system is fully utilized for scanning, then the scanning area coverage is improved, but spot shading occurs in the edge area of the lens system
Solution Approach 1:
The wedge array introduces asymmetric deflection angles that compensate for the symmetric spot shading pattern. By designing wedges with varying angles positioned at different locations in the array, the system creates asymmetric beam corrections that precisely counteract the symmetric spot shading effect, enabling full field angle utilization with uniform spot distribution.
3Manufacturing precision
If wedge elements are added to the optical system, then spot shading is eliminated, but the device complexity increases
Solution Approach 1:
The wedge array is integrated with the microlens array in a combined optical structure. By merging the beam expansion function of the microlens array with the beam deflection function of the wedge array, the system achieves spot shading elimination without requiring completely separate optical subsystems, thereby reducing overall device complexity while maintaining precision.
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 effectively eliminates spot shading and aberrations, allowing for efficient utilization of the transmission power and maintaining scanning accuracy across the entire field angle, ensuring that all beams reach the desired spot position without gaps, thereby enhancing the scanning performance of LIDAR devices.
Implementation Method 1
a wedge array situated upstream or downstream from the lens array in the radiation direction, which has a multitude of wedge elements... the beams may be influenced in such a way that a so-called spot section or a spot shading of the beams no longer occurs in the edge area of the lens system
Data Source
AI summary
An optical system is described, in particular for a LIDAR device, which includes a lens array having a multitude of microlenses and a lens system for deflecting beams out of a scanning area or into the scanning area, the lens system being situated in the beam path between the scanning area and the lens array, the system including at least one wedge array having a multitude of wedge elements situated upstream or downstream from the lens array in the radiation direction, a number of wedge elements equaling a number of microlenses. A LIDAR device is also described.