Laser Focus Positioning Accuracy Test Using Disposable Transparent Plate
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Solution Overview
Problem
Current methods for testing the positioning accuracy of femtosecond laser devices used in laser surgery, particularly for the human eye, lack a straightforward and documentable method to ensure precise alignment of the laser focus, which is critical for high-precision machining operations.
Innovation Solution
A process involving a test object transparent to laser radiation, where pulsed focused laser radiation is applied to create enduring machining structures, allowing for the assessment of focus positioning accuracy in the z-direction, with discoloration zones or cut surfaces that can be visually or camera-detected for evaluation, and reference markings for calibration verification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional testing methods using photodetectors and plasma sparks are employed, then the positioning accuracy can be examined, but the testing process becomes complex and difficult to document
Solution Approach 1:
The patent employs a disposable test object (transparent plate or block) that is used once for testing and then discarded. This eliminates the need for complex, expensive, reusable testing equipment like photodetectors and plasma spark systems. The test object contains reference markings that are permanently altered during testing, providing self-documentation of the test results without requiring complex measurement devices.
Solution Approach 2:
The patent creates a physical copy of the test results by generating enduring machining structures (discoloration zones, cut surfaces) directly in the test object. These structures serve as permanent records of the positioning accuracy, replacing complex electronic documentation systems. The reference markings in the test object act as a physical copy that can be visually inspected and archived.
2Loss of information
If enduring machining structures are generated in the test object, then the test results become documentable and archivable, but the testing process requires additional setup and materials
Solution Approach 1:
The test object itself performs the documentation function by containing reference markings that are permanently altered during testing. The machining structures generated in the test object serve as self-documenting evidence of the test results. This eliminates the need for separate documentation systems, cameras, or data storage devices, as the test object becomes its own record-keeping medium.
Solution Approach 2:
The test object is pre-prepared with reference markings (such as grid patterns, lines, or specific geometric features) before the testing process. These pre-existing markings provide a known reference framework that allows for straightforward comparison and documentation of the laser positioning accuracy. The preliminary setup of reference markings simplifies the actual testing process by providing built-in measurement references.
3Measurement precision
If a test object with reference markings is used, then the positioning accuracy in the z-direction can be accurately assessed, but the test object fabrication becomes more complex
Solution Approach 1:
The test object is made from homogeneous transparent material (such as glass, plastic, or acrylic) that is uniform in composition and optical properties. This homogeneity ensures consistent laser interaction throughout the material and simplifies fabrication, as the material can be obtained from standard manufacturing sources without requiring complex multi-component construction. The uniform material properties make the reference markings and machining structures predictable and measurable.
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 method provides a simple and reliable means to determine the positioning accuracy of the laser focus, enabling the user to verify compliance with precision requirements and potentially enabling or disabling the laser device for eye treatments based on test results, with the added benefit of a long-term archivable test record.
Implementation Method 1
fs laser radiation is employed... which is able to bring about a laser-induced optical breakthrough at the focus and, resulting from this, a photodisruption
Data Source
AI summary
A process is proposed for testing a laser device that has been set up to emit pulsed focused laser radiation, the focal position of which is adjustable both in and across the direction of propagation of the laser radiation. The laser device includes a contact element that is transparent to the laser radiation, with an abutment surface for abutment of an object to be machined. Within the scope of the process, a test object that is transparent to the laser radiation at least in a machining region is applied onto the abutment surface of the contact element. Then laser radiation is beamed into the test object bearing against the abutment surface and in the process the focal position is moved in accordance with a predetermined test pattern, in order to generate enduring machining structures in the test object.