Optical Assembly Reference Beam for LiDAR Thermal Drift
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Integrated optical assemblies in laser radar systems face challenges in maintaining accurate beam focus and correcting for changes in the scanning reflector's orientation or refractive index due to thermal expansion, which can introduce errors in measurement data.
Innovation Solution
The optical assembly produces a reference beam that traverses the scanning reflector multiple times, allowing for the detection of changes in the reflector's orientation or refractive index, enabling correction for these changes and minimizing errors by using a collimated reference signal that is refocused on the source, thereby stabilizing the measurement beam.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the scanning reflector is made moveable to adjust beam focus, then the adaptability of the optical assembly is improved, but the stability of the reflector's orientation is worsened, leading to measurement errors
Solution Approach 1:
The patent implements a feedback mechanism by producing a reference beam that traverses the scanning reflector multiple times and comparing it with the measurement beam. This allows the system to detect orientation changes of the scanning reflector and compensate for them, thus maintaining measurement accuracy despite the reflector's moveability for focus adjustment.
Solution Approach 2:
The reference beam acts as an intermediary that carries information about the scanning reflector's orientation changes. By introducing this reference beam that interacts with the same reflector, the system can indirectly measure and correct for orientation drift without affecting the primary measurement function.
2Measurement precision
If the scanning reflector is positioned precisely for optimal focus, then the measurement precision is improved, but the device complexity increases due to alignment requirements
Solution Approach 1:
The system performs self-alignment and self-correction by using the reference beam to automatically detect and compensate for misalignments of the scanning reflector. This eliminates the need for complex external alignment procedures and reduces the burden on operators to achieve precise positioning.
Solution Approach 2:
The reference beam is produced and compared with the measurement beam in advance to detect any orientation changes of the scanning reflector before they affect the measurement accuracy. This preliminary detection allows for proactive correction rather than reactive adjustment.
3Device complexity
If thermal expansion of the scanning reflector is not compensated, then the device complexity is reduced, but the measurement precision deteriorates due to refractive index changes
Solution Approach 1:
The reference beam provides continuous feedback about thermal expansion effects on the scanning reflector's refractive index and orientation. By comparing the reference beam with the measurement beam, the system can detect thermal drift and compensate for it, maintaining measurement precision without requiring complex active thermal control systems.
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 ensures high accuracy and stability of the measurement beam, allowing for precise data collection and correction of errors caused by thermal changes or misalignment of the scanning reflector, enhancing the reliability of the laser radar system.
Implementation Method 1
a lens, a scanning reflector and a fixed reflector that are oriented relative to each other such that a beam from the light source is reflected by the scanning reflector
Implementation Method 2
a beam from the light source is reflected by the scanning reflector to the fixed reflector, and reflected light from the fixed reflector is reflected again by the scanning reflector
Implementation Method 3
the scanning reflector that is preferred in the present invention is a corner cube that also functions as a retroreflector (because of the manner in which it reflects and transmits light, as it redirects the light)
Implementation Method 4
the optical assembly produces a reference beam that is related to the optical characteristics of the scanning reflector, or to changes in position or orientation of the scanning reflector relative to the source
Data Source
AI summary
An integrated optical assembly is provided, with enhancements that are particularly useful when the integrated optical assembly forms part of a laser radar system. The integrated optical assembly produces a reference beam that is related to the optical characteristics of a scanning reflector, or to changes in position or orientation of the scanning reflector relative to a source. Thus, if the scanning reflector orientation were to shift from its intended orientation (due e.g. to thermal expansion) or if characteristics of the scanning reflector (e.g. the index of refraction of the scanning reflector) were to change on account of temperature changes, the reference beam can be used to provide data that can be used to account for such changes. In addition, if the scanning reflector were to be positioned in an orientation other than the orientation desired, the reference beam can be used in identifying and correcting that positioning.