Beam Splitting Device for Multiple-Spot Laser Refractive Surgery
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Solution Overview
Problem
Existing refractive ophthalmic surgery apparatus using laser radiation face challenges such as inferior focusing ability, complex optics, and non-concentric spot paths due to beam splitting and focusing issues, leading to undesired energy distribution and increased complexity.
Innovation Solution
A beam splitting device that divides the processing beam into primary and secondary beams without changing the beam cross section, introducing an angle of separation between them, and is positioned near the pupil to maintain aperture integrity, allowing for adjustable and synchronized control of spot paths to prevent intersection, using elements like phase gratings or segmented plates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the processing beam is split into multiple partial beams by lenses, then the treatment time is shortened by processing larger partial areas simultaneously, but the beam cross section at the lenses becomes smaller causing inferior focusing ability and larger spots
Solution Approach 1:
The beam splitting device divides the processing beam into multiple partial beams (e.g., three beams) that are spatially separated, allowing simultaneous processing of multiple spots. This segmentation enables parallel processing to reduce treatment time while maintaining proper beam characteristics for each spot.
Solution Approach 2:
The invention introduces beam separation in a spatial dimension by creating angular divergence between partial beams. This dimensional approach allows multiple spots to be processed simultaneously without compromising the cross-sectional area and focusing ability of individual beams.
2Productivity
If lenses are used to split the beam into partial beams, then multiple spots are generated, but convergent beams form with foci located within the optical system causing high field strengths and undesired effects
Solution Approach 1:
The beam splitting device extracts and separates the processing beam into multiple partial beams with angular divergence, preventing the formation of convergent beams with foci within the optical system. This extraction of the beam splitting function from traditional lens-based systems eliminates the harmful convergent effects.
Solution Approach 2:
The beam splitting device acts as an intermediary element that divides the beam into multiple paths with angular separation, serving as a mediator between the laser source and the processing spots. This intermediary function prevents direct convergence of beams within the optical system while still achieving multiple spot generation.
3Productivity
If a beam splitting device is introduced to generate multiple foci, then processing speed increases, but the device complexity increases due to additional optics and focusing elements
Solution Approach 1:
The beam splitting device is designed to perform multiple functions: it divides the beam into multiple partial beams, introduces angular divergence to separate the beams spatially, and maintains proper beam characteristics for focusing. This multi-functionality reduces the need for additional separate optical elements, thereby limiting complexity increase.
4Productivity
If a fixed offset between individual spots is generated anterior to the scanner, then beam splitting is achieved, but a spiral scan results in non-concentric paths with points of intersection
Solution Approach 1:
The invention introduces dynamic control of the beam splitting device to adjust the offset between individual spots. This dynamic adjustment allows the system to maintain concentric spot paths during spiral scanning by compensating for the fixed offset, preventing path intersections while maintaining proper spot separation.
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 solution enables efficient and controlled generation of multiple focus spots in the cornea without the drawbacks of existing technologies, ensuring consistent spot size and preventing optical breakthroughs, while allowing for both single-spot and multiple-spot processing modes.
Implementation Method 1
The beam splitting device preferably comprises a diffractively effective element, which may be provided as a phase grating
Data Source
AI summary
An apparatus for refractive ophthalmic surgery by laser radiation including a source of radiation which emits a processing beam a beam path for focusing and scanning. The beam path focuses the processing beam into a cornea of an eye and shifts a position of a focus therein. A beam splitting device generates several foci in the cornea and divides the processing beam into a primary beam and at least one secondary beam. The primary and secondary beams have substantially the same cross section as the processing beam which is incident on the beam splitting device and the beam-splitting device introduces a separation between the primary and secondary beams. The primary and secondary beams expand in the beam path. A contact glass induces a pre-defined geometric boundary surface at the cornea.