LiDAR Optical Layout for Near-Range Defocus and Echo Loss
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Solution Overview
Problem
LiDAR systems designed for long-range detection often suffer from defocusing issues when detecting nearby targets due to a configuration that prioritizes distant targets, leading to reduced imaging clarity and target recognition capabilities.
Innovation Solution
The LiDAR system is redesigned with a receiving lens focal length of 40 mm ≤ fRX ≤ 80 mm, a beam splitter with a cylindrical interface, and a scanning module using multiple lasers and a rotating mirror with transition surfaces to enhance echo light reception and reduce optical loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the receiving lens focal length is reduced to 40-80mm, then the spot size on the receiving surface is reduced and more light energy is received, but the long-range detection capability may be compromised
Solution Approach 1:
The patent changes the focal length parameter of the receiving lens to a specific range (40-80mm) to optimize the spot size and light energy reception. This parameter adjustment resolves the contradiction by finding an optimal value that improves near-range detection while maintaining acceptable long-range performance through the overall optical system design.
2Loss of energy
If the beam splitter transmitting portion size is reduced, then the object height for the rear mirror group is reduced and spot energy is enhanced, but the detection light transmission may be insufficient
Solution Approach 1:
The patent applies local quality by creating a beam splitter with different regions having different properties: a light-transmitting portion for detection light and a light-reflecting portion for echo light. The interface between these portions is designed as a cylindrical surface with specific radial dimensions (10-12mm), optimizing the local light transmission and reflection characteristics to resolve the contradiction between spot energy enhancement and detection light transmission.
3Productivity
If the receiving lens focal length is reduced, then the spot size is reduced and receiving efficiency is improved, but the imaging clarity for distant targets may deteriorate
Solution Approach 1:
The patent optimizes the receiving lens focal length parameter within the range of 40-80mm to achieve a balance between spot size reduction and imaging quality. This parameter optimization improves light reception efficiency while maintaining acceptable imaging clarity through the integrated optical system design.
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 improves the energy and clarity of echo light detection across various ranges by ensuring more of the light spot is received on the detector, optimizing transceiver efficiency and reducing defocusing effects.
Implementation Method 1
the receiving lens satisfies a conditional formula: 40 mm≤fRX≤80 mm, wherein fRX is the effective focal length of the receiving lens... when the effective focal length of the receiving lens fRX is reduced, the size of the spot received on the receiving surface can be achieved to reduce the size of the spot, so that all or most of the spot can be received by the receiving surface, thereby enhancing the energy of the echoed light received by the receiver
Implementation Method 2
The beam splitter includes a light transmitting portion and a reflecting portion, and the reflecting part is provided at the periphery of the light-transmitting portion, the light-transmitting portion is used for transmitting the light, the light-transmitting part is configured to transmit the detected light, and the reflecting portion is configured to reflect the echo light
Data Source
AI summary
The present application discloses a LiDAR and a movable device. The LiDAR includes an emission module, a receiving module, a beam splitter and a scanning module. The receiving lens meets 40 mm≤fRX≤80 mm, where fRX is the effective focal length of the receiving lens. The beam splitter includes a light transmitting portion and a reflecting portion, the reflecting portion being disposed at the periphery of the light transmitting portion. The scanning module is configured to emit the detected light to the target object, and to transmit the echo light to the receiving module.