Laser Radar Device Multi-Layer Scanning with Tilted Polygon Mirror
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Solution Overview
Problem
Conventional laser radar devices face increased costs and size issues when performing multi-layer scanning in the vertical direction, as they require multiple photodetectors and mirror surfaces, which are expensive and bulky, especially for long-distance applications.
Innovation Solution
The use of multiple light beams with different output angles and a polygon mirror with tilted mirror surfaces allows for multi-layer scanning in the vertical direction without increasing the number of photodetectors or mirror surfaces, maintaining a compact and cost-effective design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple photodetectors are arranged in the vertical direction to achieve multi-layer scanning, then the detection capability in the vertical direction is improved, but the cost and device size are significantly increased
Solution Approach 1:
The patent merges the functions of multiple photodetectors into a single photodetector by combining optical scanning in the horizontal direction with electronic processing of reflected light signals. The single photodetector receives light reflected from multiple vertical layers through temporal and spatial separation, eliminating the need for multiple physical photodetector elements arranged vertically.
Solution Approach 2:
The patent transitions from a vertical arrangement of multiple photodetectors to a horizontal optical scanning approach. By introducing temporal dimension (sequential detection) and spatial dimension (horizontal beam scanning), the system achieves multi-layer detection capability without increasing vertical device complexity.
2Adaptability or versatility
If the number of mirror surfaces in the polygon mirror is increased to divide the detection area into more layers, then the multi-layer scanning capability is improved, but the size of the polygon mirror and the whole device is enlarged
Solution Approach 1:
The patent combines horizontal optical scanning with temporal signal processing to achieve vertical layer differentiation. Instead of using multiple mirror surfaces to redirect light to different detectors, the system uses a single scanning mirror that sequentially illuminates different vertical layers while the photodetector and processing system differentiate layers through timing and signal analysis.
Solution Approach 2:
The patent replaces the mechanical solution of multiple mirror surfaces with an optical-electronic hybrid approach. The vertical layer differentiation is achieved through electronic processing of light signals detected in sequence, substituting mechanical complexity (multiple mirrors) with optical scanning and electronic control.
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 approach enables efficient multi-layer scanning in the vertical direction with reduced costs and device size, allowing for accurate detection over multiple ranges without the need for additional photodetectors or mirror surfaces, thus maintaining a compact and affordable laser radar device.
Implementation Method 1
a photodetector such as a photodiode that receives the laser light which is reflected by the object in front of the vehicle, and that converts it into a voltage signal
Implementation Method 2
an optical receiver including an optical element such as a lens that guides the reflected light toward the photodetector
Implementation Method 3
a polygon mirror or a galvanometer mirror has been used as the optical scanner. By scanning a laser beam by a mirror device
Data Source
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AI summary
Disclosed is a laser radar device including a modulated light beam generator that emits light beams to a target, a photodetector that receives reflected light; a reflected light condenser that condenses the reflected light; a rotator that rotates around a rotation axis; and mirrors included in the rotator that scan the light beams, and guide the reflected light to the reflected light condenser, wherein an angular detection range in a vertical direction is divided into a plurality of layers, wherein mirror surfaces of the mirrors are tilted by corresponding tilt angles relative to the rotation axis, the tilt angles being different from each other, wherein the modulated light beam generator emits the light beams in the vertical direction, the light beams having different emission angles, and wherein a difference between the emission angles corresponds to the angular detection range of one layer in the vertical direction.