Vibrated Polarizing Beam Splitter for Return Light Detection
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Solution Overview
Problem
Polarizing beam splitters in LIDAR systems cause loss of return light due to reflection of light with the same polarization state, reducing the effectiveness of light detection.
Innovation Solution
A vibrated polarizing beam splitter is actuated between two angles to optimize light transmission and reflection based on polarization state, ensuring maximum light reaches the detector.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a polarizing beam splitter is used to reflect emitted light and transmit return light, then the system can address parallax issues and separate emission/detection paths, but approximately half of the return light is lost due to polarization-dependent reflection
Solution Approach 1:
The polarizing beam splitter is made dynamically adjustable by incorporating a motor or actuator mechanism that can change its angular orientation. This allows the device to switch between different operational modes: reflecting emitted light toward the scan mirror while transmitting return light to the detector. The dynamic adjustment resolves the contradiction by enabling the same component to optimize for different light paths at different times.
Solution Approach 2:
The invention changes the angular parameter of the polarizing beam splitter to control its optical behavior. By adjusting the angle of the beam splitter, the system can maximize transmission of return light while maintaining effective reflection of emitted light. This parameter change allows the system to overcome the fixed 50% light loss inherent in static polarizing beam splitter configurations.
2Reliability
If the polarizing beam splitter is fixed at a single angle, then the device structure is simple and stable, but it cannot simultaneously optimize both emission reflection and return light transmission
Solution Approach 1:
The system transitions from a static to a dynamic configuration by adding a motorized adjustment mechanism. This allows the polarizing beam splitter to be repositioned between predetermined angles corresponding to different operational phases (emission vs. detection). The dynamic capability enables optimized performance without requiring multiple separate components.
Solution Approach 2:
The polarizing beam splitter is adjusted periodically between different angular positions synchronized with the LIDAR operating cycle. During the emission phase, the beam splitter is positioned to optimize reflected light direction; during the detection phase, it is repositioned to maximize transmitted light to the detector. This periodic adjustment resolves the contradiction by allowing optimal performance at different times without requiring complex simultaneous multi-function 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
The solution enhances light detection by allowing nearly all return light to be transmitted to the detector, improving the system's ability to collect data from the environment.
Implementation Method 1
The polarizing beam splitter may reflect s polarized light and allow p polarized light to pass through
Implementation Method 2
The polarizing beam splitter may be used to reflect emitted light from the emitter towards a scan mirror
Data Source
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Figure 1B
Figure 1C
AI summary
A vibrated polarizing beam splitter for improved return light is disclosed. An example method may involve emitting, by an emitter, a first light pulse, and reflecting, by a polarizing beam splitter in a first position, the first light pulse, wherein the polarizing beam splitter is at a first angle of incidence in the first position. The example method may also involve adjusting, subsequent to the polarizing beam splitter reflecting the first light pulse, a position of the polarizing beam splitter from the first position to a second position, wherein the polarizing beam splitter is at a second angle of incidence in the second position. The example method may also involve transmitting, by the polarizing beam splitter, a return light pulse through the polarizing beam splitter, the return light pulse based on the first light pulse. The example method may also involve detecting, by a detector, the return light pulse.