Prism Covering Device for Stray Light Reduction in Laser Distance Measurement
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Solution Overview
Problem
Measuring devices using light beams face challenges in reducing stray light, which degrades the precision of distance measurements, especially when using higher power lasers, as the dynamic range is not effectively expanded, leading to increased stray light and reduced usable light ratios.
Innovation Solution
A covering device is placed on the prism to prevent stray light generation and incidence on the receiver, specifically designed to minimize coverage of usable light while effectively blocking stray light, with configurations such as edge coverage, frame shapes, and antireflection coatings to maximize the ratio of usable to stray light.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If a higher power laser is used to measure greater distances, then the measurement range is extended, but the stray light increases proportionally, reducing the precision of the measured result
Solution Approach 1:
The patent extracts and removes the harmful stray light from the optical path by using a covering device that selectively blocks stray light while allowing usable light to pass through to the detector, thereby resolving the contradiction between extended measurement range and maintained precision
Solution Approach 2:
The covering device acts as an intermediary element positioned in the optical path between the prism and detector, selectively filtering stray light while transmitting usable light, thus enabling high-power laser operation without proportionally increasing stray light impact
2Productivity
If a prism is placed in the central area of the lens array to couple light into the optical axis, then light coupling efficiency is improved, but crosstalk effects and stray light generation increase
Solution Approach 1:
The covering device removes the harmful stray light generated by the prism by blocking it before it reaches the detector, while leaving the useful light path intact, thus resolving the contradiction between efficient light coupling and stray light reduction
Solution Approach 2:
The covering device applies selective blocking only in the specific regions where stray light is generated by the prism, rather than uniformly blocking all light paths, thereby maintaining high coupling efficiency while reducing stray light at its source
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 significantly reduces stray light incidence, enhancing the dynamic range and precision of distance measurements by minimizing interference from stray light while maintaining a high intensity of usable light, thus improving the accuracy of distance measurement devices.
Implementation Method 1
a prism (120) placed on one of the lenses (100a, 100b) with a slanted surface (130) for coupling of a light ray (115) from a light source (140) placed lateral to the optical axis (110) into the optical axis (110)
Implementation Method 2
a covering device (160) placed on the prism (120) for preventing incidence of stray light on the receiver (150)
Data Source
AI summary
A device for measurement by means of a light ray is equipped with a covering device for reducing stray light. The device comprises an array of lenses along an optical axis; a prism attached to one of the lenses with a slanted surface for coupling of the light ray incident from a light source placed lateral to the optical axis, onto the optical axis, so that the light ray can pass through the array of lenses along the optical axis; a receiver for receipt of a share of the light ray reflected by an object; and a covering device for at least one area of the prism that scatters a share of the light ray as stray light to the receiver.