Rotating Aperture Laser Scanner for Low-Noise Beam Tracking
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Solution Overview
Problem
Existing laser scanners face issues with measurement errors and poor signal-to-noise ratios due to scatter reflections and complex synchronization requirements in the receiver's field of view, which are exacerbated by the need to position the laser transmitter or coupling mirror within the receiver's field of view, leading to obstructed view and signal loss.
Innovation Solution
A laser scanner design with a rotationally fixed receiver aperture and optical element that synchronizes the receiver's field of view with the deflected transmitting beam, eliminating the need for complex synchronization and reducing scatter reflections by separating the transmitting beam from the receiver's field of view, thereby improving signal-to-noise ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the receiver's field of view is made large to receive the reflected beam, then the receiving capability is improved, but the signal-to-noise ratio deteriorates due to more ambient light entering
Solution Approach 1:
The aperture diaphragm is mounted on the shaft to rotate synchronously with the optical element, making the receiver's field of view dynamic rather than static. This allows the field of view to track the deflected transmitting beam while maintaining a limited angular aperture, thus receiving the reflected beam effectively without admitting excessive ambient light.
2Volume of moving object
If the laser transmitter or coupling mirror is positioned within the receiver's field of view to save space, then the device compactness is improved, but the received signal strength deteriorates due to obstructed view
Solution Approach 1:
By making the aperture diaphragm rotate with the shaft, the receiver's field of view dynamically tracks the deflected transmitting beam. This allows the laser transmitter to be positioned within the nominal field of view area without causing obstruction, as the aperture only admits light from the specific angular position where the beam is deflected.
3Productivity
If the optical element rotates to deflect the transmitting beam, then the scanning function is achieved, but the receiving accuracy deteriorates due to lag angle causing beam drift out of field of view
Solution Approach 1:
The aperture diaphragm is mounted on the rotating shaft, creating a dynamic field of view that rotates synchronously with the optical element. This dynamic tracking compensates for the lag angle effect, ensuring the receiver's field of view continuously follows the deflected transmitting beam throughout the scanning motion.
Solution Approach 2:
The rotating aperture diaphragm acts as an intermediary between the stationary receiver body and the moving optical element. It transfers the angular position information from the optical element to the receiver's field of view, enabling synchronized tracking without complex mechanical linkages.
4Reliability
If the receiver's field of view is directed at the rotating optical element to receive the beam, then the receiving capability is improved, but the measurement accuracy deteriorates due to scatter reflections coupling into the receiver
Solution Approach 1:
The aperture diaphragm rotates with the shaft, creating a dynamic field of view that tracks the deflected beam. This allows the aperture to be positioned such that it only admits light from the specific angular position where the reflected beam passes, excluding scatter reflections from other directions while maintaining receiving capability.
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 design ensures improved reception properties with reduced measurement errors and enhanced signal-to-noise ratio by maintaining synchronized field of view without complex adjustments, allowing faster scanning and minimizing unwanted reflections.
Implementation Method 1
an optical element deflecting the transmitting beam which is either reflective or refracting
Implementation Method 2
an optical element deflecting the transmitting beam which is either reflective or refracting
Implementation Method 3
From time-of-flight measurements of the reflected beam, i.e., the received beam, the distances to the targets are determined
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
A laser scanner for scanning an environment (2) comprises a laser transmitter (3) for emitting a transmitting beam (4); a shaft (10) rotatable about a rotational axis (9); an optical element (5, 5') deflecting the transmitting beam (4), which is either reflective or refracting and is mounted on the shaft (10) in a rotationally fixed manner relative to it for fanning out the transmitting beam (4) along a conical shell (11) or conical shell segment; and a receiver (6) for receiving the transmitting beam (4) reflected from the environment (2) as a receiving beam (7); wherein the receiver (6) has an aperture diaphragm (13) which is mounted on the shaft (10) in a rotationally fixed manner relative to it in order to align the field of view (12) of the receiver (6) with the transmitting beam (4) deflected at the optical element (5, 5').