LiDAR Beam Splitter with Selective Stray-Light Blocking
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Solution Overview
Problem
The presence of leading light within LiDAR systems affects detection accuracy due to stray light reflections, causing crosstalk and reducing the effectiveness of distance and direction measurements.
Innovation Solution
Incorporating a first extinction device between the beam splitter and receiver in the LiDAR, which blocks optical signals in non-primary optical path regions, thereby preventing stray light from reaching the receiver and improving detection accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a beam splitter is used to separate emission light and echo light in a TOF LiDAR system, then the LiDAR can perform distance and direction detection, but stray light reflections cause leading light that affects detection accuracy
Solution Approach 1:
A first extinction device is introduced as an intermediary component between the beam splitter and the detector. This extinction device specifically targets and blocks stray light in non-primary optical paths while allowing primary echo light to pass through, thereby eliminating leading light interference without affecting the main detection function
Solution Approach 2:
The optical path is segmented into primary optical paths (carrying valid echo light) and non-primary optical paths (carrying stray light). The first extinction device is positioned to selectively block only the non-primary paths, separating the useful signal from the harmful interference based on their different spatial distributions
2Object-affected harmful factors
If the surface transmittance of components in the light transmission path is less than 100%, then light reflection occurs causing leading light, but increasing transmittance is difficult to achieve
Solution Approach 1:
Instead of attempting to eliminate the inherent reflectivity of optical components (which would require achieving 100% transmittance), the invention accepts the reflection as inevitable and converts the harmful reflected light into a manageable problem by blocking it in specific non-primary optical paths using the first extinction device
Solution Approach 2:
The first extinction device serves as a mediator that handles the consequence of imperfect transmittance by selectively blocking reflected stray light, allowing the use of practical optical components with realistic transmittance values while still achieving high detection accuracy
3Object-affected harmful factors
If all optical paths are blocked to eliminate stray light, then leading light interference is removed, but echo light signal is also lost reducing detection performance
Solution Approach 1:
The first extinction device applies local quality control by blocking light only in specific non-primary optical path regions where stray light predominates, while leaving the primary optical paths unaffected. This localized approach eliminates interference without sacrificing detection signal
Solution Approach 2:
Instead of blocking all optical paths (excessive action), the first extinction device performs partial blocking only in non-primary regions. The patent specifies that the energy proportion of echo light in these non-primary regions is less than a first preset value, meaning the partial blocking action eliminates harmful stray light while preserving sufficient echo light signal for accurate detection
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 solution effectively reduces the influence of stray light, enhancing detection accuracy and eliminating detection blind spots for close-range objects by blocking non-primary optical path regions, thus improving overall LiDAR performance.
Implementation Method 1
the beam splitter comprises a light-transmitting portion and a light-reflecting portion connected to the light-transmitting portion, the light-transmitting portion is configured to receive the emission light emitted by the transmitter, and transmit the emission light to the target object outside the housing; the light-reflecting portion is configured to receive the echo light reflected by the target object outside the housing, and transmit the echo light to the receiver
Implementation Method 2
the first extinction device is configured to block the optical signal in the non-primary optical path regions from being transmitted to the receiver
Data Source
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AI summary
A LiDAR and a movable device are provided. The LiDAR includes a housing, a transmitter, a receiver, a beam splitter and a first extinction device. The beam splitter includes a light-transmitting portion and a light-reflecting portion. The first extinction device locates inside the housing and between the beam splitter and the receiver along the transmission path of echo light, and configured to block optical signals in non-primary optical path regions from being transmitted to the receiver. The first extinction device positioned between the beam splitter and the receiver can prevent stray light in the non-primary optical path regions from being received by the receiver, reducing the stray light's impacts on the detection results and improving the detection accuracy. Since echo light energy in non-primary optical path regions accounts for a small proportion, even if the receiver does not receive this light energy, it will hardly affect the LiDAR's detection performance.