Rotating Mirror Optical System for Radar Distortion Control
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Solution Overview
Problem
Conventional laser radars face challenges in suppressing longitudinal distortion and spot rotation while maintaining a wide view field range, which affects the precision of obstacle detection in applications like vehicle collision prevention.
Innovation Solution
A scanning optical system with a rotatable mirror unit featuring a first mirror surface inclined relative to the rotation axis and a second mirror surface, where the light flux is made longer in the sub scanning angle direction than in the scanning angle direction, and the intersection angle between the mirrors is optimized to satisfy the conditional expression |θ1−90|×|α|≤225, thereby controlling longitudinal distortion and spot rotation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the spot size is made larger in the sub scanning angle direction to increase the light projecting range, then the view field range is improved, but the resolving power deteriorates
Solution Approach 1:
The invention applies different spot size characteristics in different directions: the spot size is made longer in the sub scanning angle direction to expand the view field range, while maintaining a shorter spot size in the scanning angle direction to preserve resolving power. This directional differentiation of spot characteristics resolves the contradiction between view field range and resolving power.
2Measurement precision
If the number of scanning lines is increased to improve detection precision, then the measurement precision is improved, but the device complexity increases
Solution Approach 1:
The invention changes the spot size parameter directionally, making it longer in the sub scanning angle direction and shorter in the scanning angle direction. This parameter optimization allows achieving sufficient detection precision without necessarily increasing the number of scanning lines, thereby avoiding increased device complexity.
3Area of stationary object
If the scanning angle is increased to expand the detection range, then the view field range is improved, but longitudinal distortion and spot rotation increase
Solution Approach 1:
The invention optimizes the spot size characteristics locally in different directions to compensate for distortion effects. By making the spot longer in the sub scanning angle direction and shorter in the scanning angle direction, the system maintains more accurate spot positioning across a wider scanning range, reducing the impact of longitudinal distortion and spot rotation.
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 configuration effectively suppresses longitudinal distortion and spot rotation, maintaining a wide view field range and improving the resolving power of the radar system for precise obstacle detection.
Implementation Method 1
a light flux emitted from the light source is reflected on the first mirror surface of the mirror unit
Implementation Method 2
then, proceeds to the second mirror surface, further reflected on the second mirror surface, and projected so as to scan on the object
Data Source
AI summary
Scanning optical system, comprising a rotatable mirror unit including first and second mirror surfaces each inclining relative to a rotation axis, and a light projecting system including a light source which emits light flux toward an object through the mirror unit. The light flux is reflected on the first mirror surface, then to the second mirror surface, and projected so as to scan on the object correspondingly to rotation of the mirror unit. The mirror unit includes multiples pairs of the first and second mirror surfaces, and the respective intersection angles of the multiples pairs are different from each other. In one rotation of the mirror unit, light flux emitted from the light source is reflected on the second mirror surfaces, and is projected sequentially, thereby to scan a measurement range in which the object is measured. Length in a sub scanning direction of the light flux and intersection angles of the multiples pairs correspond to length in a sub scanning direction of the measurement range.