Laser Beam Measuring Device With Coinciding Focal Lens System
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Solution Overview
Problem
Existing methods for measuring focused laser beams, such as those used in ophthalmic laser surgery, face significant measurement errors due to the dependency of magnification scale on beam diameter, especially when using single magnification lenses for beams with varying waist diameters.
Innovation Solution
A measuring device employing a magnification lens system with at least two lenses in series, where each pair has coinciding focal points, along with an electronic image sensor and adjustable components to ensure a constant magnification scale, allowing precise determination of the laser beam's waist diameter and beam profile.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single magnification lens is used to measure laser beams with varying waist diameters, then the measurement setup is simple, but the magnification scale becomes dependent on beam diameter leading to significant measurement errors
Solution Approach 1:
The patent divides the single magnification lens into a system of multiple lenses (at least two lenses with coinciding focal points). This segmentation allows the magnification scale to become independent of beam diameter, as each lens contributes to the overall magnification in a way that compensates for variations in waist diameter, thereby resolving the measurement error problem while maintaining reasonable system complexity
Solution Approach 2:
The patent changes the optical parameters of the magnification system by using multiple lenses with specific focal point arrangements. This parameter change transforms the magnification characteristic from being diameter-dependent to diameter-independent, enabling accurate measurements across different beam sizes without requiring complex adjustment mechanisms
2Measurement precision
If a magnification lens system with multiple lenses is used to achieve constant magnification scale, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent designs the magnification lens system to serve multiple functions: it provides constant magnification for different beam diameters, maintains a fixed magnification scale, and enables accurate determination of various beam parameters (waist diameter, divergence, diffraction index). This multi-functionality justifies the increased device complexity by delivering comprehensive measurement capabilities from a single system configuration
Solution Approach 2:
The patent uses an electronic image sensor to capture an optical copy of the magnified laser beam. This copying approach allows non-contact measurement and enables digital processing of beam parameters, which compensates for the increased optical complexity by providing automated analysis and reducing the need for manual measurement procedures
3Measurement precision
If longitudinal adjustment means are added to simultaneously adjust lenses and image sensor, then measurement accuracy is improved, but device complexity and ease of operation are affected
Solution Approach 1:
The patent introduces longitudinal adjustment means that enable dynamic positioning of the lenses and image sensor along the beam path. This dynamic adjustment capability allows the system to adapt to different measurement scenarios and maintain optimal focus positioning, thereby improving measurement precision while providing the flexibility needed for various beam conditions
Solution Approach 2:
The patent employs an electronic image sensor that captures the magnified beam image, which can be used for feedback-based alignment optimization. By analyzing the captured image quality and beam parameters, the system can guide the longitudinal adjustment process to achieve optimal positioning, reducing the skill level required for manual alignment while maintaining high measurement accuracy
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 enables precise measurement of the laser beam's waist diameter and profile, reducing measurement errors and providing accurate determination of beam parameters like divergence and diffraction index, regardless of the beam's waist diameter.
Implementation Method 1
a magnification lens system with at least two lenses disposed in series in the beam path of the laser beam, wherein each pair of successive lenses of the magnification lens system has coinciding focal points
Implementation Method 2
an electronic image sensor disposed behind the magnification lens system at a focal point thereof, for capturing an image of the magnified laser beam
Data Source
AI summary
According to an embodiment, a measuring device for measuring a laser beam comprises a magnification lens system with a total of two lenses which are arranged in series in the beam path of the laser beam and whose foci are coinciding, as well as a camera which is arranged behind the two lenses in the focus of the last lens and includes an electronic image sensor which generates an electronic image of the magnified laser beam. The lenses together with the camera are adjustable along the beam path relative to a reference point of the measuring device, for the purpose of locating the beam waist of the laser beam and of determining a diameter profile of the laser beam. The measuring device further comprises an adapter enclosing the beam path for coupling the measuring device to a laser system which provides the laser beam. The adapter forms an abutment surface or the laser system, which is axially directed with respect to a beam axis of the laser beam, and permits the measuring device to be coupled in situ at the installation site of the laser system.