Optical Module Transverse Offset for Laser Rangefinder Sensor Protection
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Solution Overview
Problem
Monostatic or quasi-monostatic laser rangefinders are prone to damage due to high-intensity return radiation from targets like metal reflectors with three cube corner faces, exceeding the tolerance limits of their optical sensors, especially when the return radiation is retroreflected along the same path as the primary radiation.
Innovation Solution
An optical module with two reflector assemblies is attached in front of the optical outlet to transversely offset the primary radiation beam by 10-35 cm, ensuring the return radiation is directed away from the optical inlet, thereby reducing the power received by the sensor and preventing damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the optical inlet and outlet are superimposed or juxtaposed in monostatic or quasi-monostatic rangefinders, then the device simplicity and ease of transport are improved, but the sensor becomes vulnerable to damage from high-intensity retroreflected radiation
Solution Approach 1:
The patent introduces an optical module as an intermediary component between the optical outlet and the target. This module includes a first reflector that deflects the outgoing laser beam and a second reflector that deflects the returning beam, effectively mediating the optical path to prevent direct coupling between emission and reception while maintaining system compactness.
Solution Approach 2:
The patent transforms the monostatic configuration (zero separation) into a quasi-monostatic configuration by introducing transverse offsets through the optical module. The beam is displaced in the transverse dimension by the reflectors, creating effective separation between emission and reception paths without increasing the longitudinal footprint of the device.
2Measurement precision
If the optical sensor has high sensitivity to detect weak return radiation, then the detection capability is improved, but the sensor tolerance limit is exceeded by strong retroreflected radiation
Solution Approach 1:
The optical module acts as a mediator that differentially affects the outgoing and returning beams. The first reflector deflects the outgoing beam away from the optical axis, while the second reflector redirects the returning beam to the sensor. This intermediary system allows the sensor to receive weak scattered radiation while blocking strong direct retroreflections.
Solution Approach 2:
The patent applies different optical properties to different parts of the system. The optical module introduces localized beam manipulation through reflectors with specific orientations, creating different optical paths for emission and reception. This local differentiation allows the sensor to operate in a protected zone while maintaining high sensitivity.
3Object-affected harmful factors
If an optical module with reflectors is added to offset the beam, then the sensor protection is improved, but the device complexity increases
Solution Approach 1:
The optical module is segmented into distinct functional components: a first reflector for outgoing beam deflection and a second reflector for returning beam redirection. This segmentation allows each component to be optimized independently and simplifies the overall design by breaking down the complex beam manipulation task into manageable stages.
Solution Approach 2:
The optical module serves multiple functions simultaneously: it offsets the outgoing beam to prevent direct retroreflection, redirects the returning beam to the sensor, and maintains the compact monostatic form factor. This multi-functionality reduces the need for additional separate components, thereby limiting the increase in overall device complexity.
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 optical module effectively protects the sensor from damage by reducing the intensity of the return radiation to within safe limits without increasing the complexity or size of the rangefinder, maintaining the rangefinder's simplicity and ease of use.
Implementation Method 1
The optical module comprises two reflector assemblies which are arranged on a path of the laser beam of primary radiation emitted by the rangefinder equipped with the optical module, downstream of the optical outlet of the rangefinder, such that the primary radiation is reflected by one and then the other of the two reflector assemblies
Data Source
AI summary
An optical module (10) is attached in front of an optical outlet (21) of a monostatic or quasi-monostatic laser rangefinder (20), for the purpose of transversely offsetting a laser beam of primary radiation (F) emitted by the optical outlet. In this manner, the risk of damage to an optical sensor (23) of the rangefinder can be avoided.