Laser Device Testing via Transparent Test Object

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Solution Overview

Problem

Current methods for testing the positioning accuracy of femtosecond laser devices used in eye surgery lack simplicity and reliability, particularly in ensuring the focus positioning accuracy in the propagation direction, which is critical for precise procedures like LASIK treatments.

Innovation Solution

A method involving a transparent test object with optically contrasting discoloration structures is used to verify the focus positioning accuracy by generating permanent processing structures, allowing for easy evaluation of the laser device's calibration through visual or camera-based inspection, where the discoloration structures are created using a specified test pattern that indicates whether the focus position is within or outside a predetermined puncture area.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If complex testing methods with multiple measurement devices are used to verify focus positioning accuracy, then measurement precision is improved, but device complexity increases

Engineering Contradiction:
Improvefocus positioning accuracyVSAvoidtesting system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent creates permanent processing structures (copies) in the test object that replicate the focus trajectory. These structures serve as tangible records of the laser focus path, allowing verification without complex measurement devices. The processing structures act as permanent copies or traces of the focus movement, enabling simple visual or optical inspection instead of complex real-time measurement systems.

Inventive Principle:
Principle #26Copying

Solution Approach 2:

The test object with optically contrasting discoloration structures serves as an intermediary medium between the laser device and the evaluation process. Instead of directly measuring focus position with complex sensors, the laser creates visible processing structures in the test object that mediate the verification process, allowing accurate assessment through simple optical inspection.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If permanent processing structures are created in the test object to document focus position, then reliability of test results is improved, but the test object is damaged

Engineering Contradiction:
Improvetest result reliabilityVSAvoidtest object damage
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The test object is designed as a disposable or replaceable component that can be easily replaced after testing. The permanent damage to the test object is acceptable because it is a low-cost item intended for single or limited use, allowing reliable testing without concern for preserving the test object itself.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Measurement precision

If the test method requires specialized equipment for evaluation, then measurement precision is improved, but ease of operation deteriorates

Engineering Contradiction:
Improvefocus positioning accuracyVSAvoidtest execution simplicity
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The patent uses optically contrasting discoloration structures that change the optical properties of the test object at the focus location. These color or transparency changes make the processing structures visible through simple optical inspection or camera systems, eliminating the need for specialized measurement equipment while maintaining accurate focus verification.

Inventive Principle:
Principle #32Color changes

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 straightforward and reproducible means to assess the laser device's positioning accuracy, ensuring compliance with stringent accuracy requirements of a few micrometers, thereby enabling safe and precise eye surgery procedures.

Implementation Method 1

ultra-short-pulse laser radiation with pulse durations in the femtosecond range (possibly down to the single-digit picosecond range), which can cause a laser-induced optical breakdown in the focus and, as a result, a photodisruption

Methodology Applied
Scientific EffectPhotodisruption: Photo-oxidation

Data Source

PatentEP2621661B1Method for testing a laser device
Publication Date: 2023.03.01 ALCON INC
  • EP2621661B1 patent drawingFigure 1
  • EP2621661B1 patent drawingFigure 2~4c
  • EP2621661B1 patent drawingFigure 4a~7b

AI summary

The invention relates to a method for testing a laser device (10) which is designed to provide focused, pulsed laser radiation, the focus position (18) of which can be varied both in and perpendicular to the direction of propagation of the laser radiation. The laser device comprises a contact element (30) which is transparent to the laser radiation and has a bearing surface (34) on which an object to be treated is placed. In the course of the method, a test object (36) which is transparent to laser radiation in at least one treatment area is placed against the bearing surface of the contact element. Laser radiation is then directed inside the test object that rests on the bearing surface, and the focus position is moved in accordance with a predefined test pattern in order to produce permanent treatment structures in the test object.