Refractive Polygon Beam Steering for Wider LiDAR Field of View
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Solution Overview
Problem
Conventional polygon reflectors in LIDAR systems limit the field of view and duty cycle due to the incident light beam being coplanar with the reflective facet, restricting the collection of useful return beam data and reducing operational efficiency.
Innovation Solution
A refractive beam-steering assembly using a polygon deflector with facets that refract the incident light beam from within the deflector, allowing for enhanced field of view and duty cycle by rotating the deflector about an axis and utilizing an optic for collimating the beam on each facet.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a conventional polygon reflector is used with coplanar incident beam and reflective facet, then the structure is simple, but the field of view and duty cycle are limited
Solution Approach 1:
The patent inverts the conventional reflection geometry by using refraction instead of reflection. The incident beam enters the polygon deflector from within its interior, and the facets refract the beam outward. This inversion of the optical path allows the beam to access a wider angular range beyond the coplanar limitation of reflective facets, thereby expanding the field of view without proportionally increasing structural complexity.
Solution Approach 2:
The patent changes the optical parameter from reflection to refraction. By utilizing the refractive properties of the polygon deflector material and controlling the angle of incidence from within the deflector, the system achieves a broader effective angular range. The refraction angle can be independently controlled from the facet orientation, providing additional degrees of freedom to expand the field of view while maintaining a compact structure.
2Productivity
If a conventional polygon reflector is used, then the mechanical structure is simple, but the duty cycle is reduced due to restricted return beam data collection
Solution Approach 1:
By inverting the optical geometry from external reflection to internal refraction, the patent enables the detector array to collect return beam data from a wider angular range. The refractive facets direct reflected light from targets into the detector array more effectively, reducing data loss and improving the proportion of useful measurements, thereby increasing the duty cycle.
Solution Approach 2:
The polygon deflector acts as an intermediary optical element that actively shapes and directs the beam path. By positioning the beam source and detector array within the interior of the deflector, the system uses the deflector's refractive facets as mediators to optimize the collection of return beam data, ensuring that more reflected light reaches the detectors and improving overall system productivity.
3Productivity
If the incident beam is coplanar with the reflective facet, then the optical path is simple, but the operational efficiency is reduced
Solution Approach 1:
The patent changes the fundamental optical parameter from reflection to refraction, and repositions the beam source from external to internal. This allows the system to achieve better operational efficiency by capturing more return beam data within each rotation cycle. The increased efficiency is achieved through optimized light collection geometry rather than through complex additional optical components, maintaining relative simplicity while improving performance.
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 refractive beam-steering assembly expands the field of view and duty cycle, enabling more effective data collection and improving the operational efficiency of LIDAR systems, particularly in applications like autonomous vehicles and optical ranging.
Implementation Method 1
The optic is configured to collimate a first beam to be incident on a particular facet of the plurality of facet
Implementation Method 2
The particular facet of the plurality of facets is configured to refract the first beam in the first plane between a first angle and a second angle as the polygon deflector rotates about the first axis to output a second beam
Data Source
AI summary
A LIDAR apparatus can include a polygon deflector that includes a plurality of facets. The LIDAR apparatus can include a motor rotatably coupled to the polygon deflector. The motor is configured to rotate the polygon deflector about a first axis orthogonal to a first plane. The LIDAR apparatus can include an optic positioned within an interior of the polygon deflector. The optic collimates a first beam to be incident on a particular facet of the plurality of facet. The particular facet of the plurality of facets refracts the first beam in the first plane between a first angle and a second angle as the polygon deflector rotates about the first axis to output a second beam.