Laser Beam Profiler Using Polarization-Compensated Prisms
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Solution Overview
Problem
Existing laser beam profiling technologies fail to accurately measure the profile of a focused laser beam applied to a workpiece due to aging-induced shifts in optical elements and overlapping measurement beams, leading to inaccurate results.
Innovation Solution
A laser beam profiler unit with a magnifying optical system, paired transmission prisms, and an image capturing element that attenuates and magnifies the focused laser beam without returning it to the processing optical system, allowing for accurate measurement of the intensity distribution and shape of the laser beam applied to the workpiece.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the focused laser beam is measured directly, then the measurement should reflect the actual beam applied to the workpiece, but the beam cannot be returned to the processing optical system without causing overlapping and ghosting that reduces measurement accuracy
Solution Approach 1:
The patent extracts the focused laser beam from the processing optical system by using a beam splitter positioned at the focal point. The beam splitter separates the measured beam path from the processing beam path, allowing the beam to be diverted to the measurement system without returning to or overlapping with the processing optical system, thereby eliminating ghosting effects
Solution Approach 2:
The patent introduces a beam splitter as an intermediary optical element that mediates between the focused laser beam and the measurement system. The beam splitter redirects the beam to the measurement path while allowing the processing beam path to remain unaffected, preventing overlapping and ghosting between measurement and processing beams
2Illumination intensity
If the laser beam is attenuated using transmission prisms, then the beam intensity is reduced for safe measurement, but polarization-dependent attenuation may cause measurement errors
Solution Approach 1:
The patent combines two transmission prisms with orthogonal polarization orientations to create a polarization-compensated attenuation system. One prism attenuates S-polarized light while the other attenuates P-polarized light, and their combined effect provides uniform attenuation for both polarization states, eliminating measurement errors caused by polarization-dependent attenuation
Solution Approach 2:
The patent uses transmission prisms with asymmetric polarization characteristics, where each prism is oriented to preferentially attenuate one polarization state. By arranging them orthogonally, the asymmetric attenuation of individual prisms combines to produce symmetric, polarization-independent overall attenuation
3Measurement precision
If the spot diameter is increased for better measurement resolution, then the intensity distribution can be measured more accurately, but the beam must be magnified which adds optical complexity
Solution Approach 1:
The patent designs the magnifying optical system to serve multiple functions: it magnifies the spot diameter for improved measurement resolution, maintains the beam's intensity distribution profile, and interfaces with the existing beam splitter and transmission prism system. This multi-functionality justifies the added optical complexity by providing comprehensive measurement capabilities
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
Enables precise measurement of the focused laser beam's intensity distribution and shape without ghosting, ensuring accurate application of the laser to the workpiece by attenuating and magnifying the beam effectively.
Implementation Method 1
the first transmission prism and the second transmission prism serve as paired transmission prisms, one of the paired transmission prisms attenuates P-polarized light of the laser beam at a higher attenuation rate, and the other of the paired transmission prisms attenuates S-polarized light of the laser beam at a higher attenuation rate
Implementation Method 2
a second transmission prism for further attenuating a laser beam reflected by the first transmission prism
Implementation Method 3
a magnifying optical system for magnifying a spot diameter of the laser beam oscillated from the laser oscillator and focused by a condensing lens
Implementation Method 4
an image capturing element for detecting the laser beam reflected by the second transmission prism
Data Source
AI summary
A laser beam profiler unit for measuring an intensity distribution of a laser beam oscillated from a laser oscillator includes a magnifying optical system for magnifying a spot diameter of the laser beam oscillated from the laser oscillator and focused by a condensing lens, a first transmission prism for attenuating the laser beam, a second transmission prism for further attenuating a laser beam reflected by the first transmission prism, an image capturing element for detecting the laser beam reflected by the second transmission prism, and an analyzer for analyzing an intensity distribution of a spot of the laser beam from data of the laser beam detected by the image capturing element.