Laser Refractive Index Planning With Closed-Loop Local Correction
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Solution Overview
Problem
Conventional refractive corrections, such as laser vision corrections and intraocular lens implantations, suffer from residual errors due to measurement inaccuracies, tissue variations, and patient-specific properties, necessitating subsequent corrections like spectacles or contact lenses, and current methods fail to precisely correct local refractive index variations.
Innovation Solution
A planning method and device for a laser processing apparatus that uses an indicator structure to characterize and define a target refractive index profile, determining a scanning pattern for pulsed laser radiation to achieve a desired refractive index change, with a closed-loop control system to adjust for deviations and ensure precise correction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional laser vision correction methods are used, then refractive error correction is achieved, but residual errors occur due to measurement inaccuracies and tissue variations
Solution Approach 1:
The patent implements a closed-loop control system where the actual refractive index change is measured using optical methods (e.g., wavefront sensing, OCT) and fed back to the control unit. The control unit then adjusts the laser processing parameters in real-time to compensate for deviations from the target profile, thereby resolving the contradiction between measurement precision and correction reliability.
Solution Approach 2:
The patent performs preliminary characterization of the indicator structure and pre-calculates the required laser scanning pattern before the actual correction process. This preliminary planning, combined with real-time monitoring, ensures that the refractive index change closely matches the target profile, addressing both measurement precision and reliability concerns.
2Ease of operation
If a single treatment method is used to correct refractive index, then the procedure is simple, but precise correction of local variations cannot be achieved
Solution Approach 1:
The patent divides the treatment into multiple controllable parameters including spatial scanning pattern, pulse duration, pulse energy, and repetition rate. Each parameter can be independently adjusted to create precise local refractive index changes, enabling complex correction profiles while maintaining operational simplicity through automated control.
Solution Approach 2:
The patent employs dynamic adjustment of laser processing parameters during the treatment process. The scanning pattern and pulse parameters are continuously adapted based on real-time feedback from the indicator structure characterization, allowing precise correction of local refractive index variations while keeping the overall procedure simple and automated.
3Manufacturing precision
If multiple treatment steps are implemented for correction, then refractive accuracy improves, but treatment time and complexity increase
Solution Approach 1:
The patent implements continuous monitoring and adjustment throughout the laser treatment process, eliminating the need for separate pre- and post-treatment measurement steps. The closed-loop control enables real-time optimization of the refractive index change, achieving high precision correction in a single continuous treatment rather than multiple discrete steps.
4Measurement precision
If indicator structure characterization is performed, then refractive index change can be precisely controlled, but additional measurement and control complexity is introduced
Solution Approach 1:
The patent introduces an indicator structure as an intermediary element that simplifies the measurement and control process. This indicator structure serves as a proxy for the actual tissue, enabling non-invasive optical characterization and feedback without requiring direct measurement of the treatment target, thereby reducing overall system complexity while maintaining high precision.
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 correction of refractive index variations, including local adjustments, reducing the need for subsequent corrections and improving accuracy by continuously monitoring and adapting the laser-induced refractive index change.
Implementation Method 1
the introduction of the pulsed radiation 2, 2′ results in this pulse energy changing the refractive index of the tissue, or else of an artificial optical element, at this point 17 in a targeted manner
Implementation Method 2
characterizing an actual behavior of an indicator structure in an examination zone arranged in an optical path downstream of the processing zone transilluminated by examination radiation
Data Source
AI summary
Planning methods and a planning device for generating control data for a control unit of a laser treatment device for changing a refractive index in the treatment zone of a transparent organic material, a laser treatment device, and a computer program product. The invention facilitates precise correction of the refractive index and thus adjusts the previously planned profile of the refractive index in the transparent organic material region to be treated during the treatment. Even highly locally limited refractive index variations are correctable. Data describing the actual behavior of the indicator structure in the examination zone are considered, and control data is output to the control unit at specified intervals during the treatment of the material in the treatment zone, wherein the last described behavior of the indicator structure in the examination zone is constantly used as new actual behavior of the indicator structure to ascertain the control data.