Birefringent Compound Lens for Faster Ophthalmic Laser Fragmentation
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Solution Overview
Problem
Current femtosecond laser systems for ophthalmic surgical procedures are limited by long procedure times, requiring efficient methods to reduce the duration of laser-assisted surgeries like LACS without compromising accuracy and patient experience.
Innovation Solution
A multifocal laser beam delivery system that utilizes a compound lens comprising a glass lens and a birefringent lens to split femtosecond laser pulses into ordinary and extraordinary beams, spatially and temporally separated, allowing for increased scanning rates and improved lens fragmentation efficiency without modifying the laser engine or scanner.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a single beam is delivered sequentially to create photodisruption, then the laser system maintains simple optics, but the procedure time is long
Solution Approach 1:
The patent divides a single laser beam into two separate beams using a beam splitter, allowing simultaneous delivery of laser pulses to different locations in the target tissue. This segmentation enables parallel processing, effectively doubling the productivity without requiring modification of the laser engine or scanner system.
Solution Approach 2:
The patent combines the optical paths of two laser beams through a compound lens system that focuses both beams to separate focal points in the target. This merging approach allows simultaneous photodisruption at multiple locations while maintaining a single laser source, resolving the contradiction between productivity improvement and device complexity.
2Speed
If laser pulses are delivered at high repetition rate, then the scanning speed increases, but shadowing effects from plasma bubbles increase and reduce precision
Solution Approach 1:
The patent separates the two laser beams in the spatial dimension by focusing them to different locations, and introduces temporal separation by delivering pulses alternately rather than simultaneously. This multi-dimensional separation strategy allows high scanning rates while minimizing shadowing effects, as the alternating pulse delivery ensures that plasma bubbles from one beam do not interfere with the other beam's focal spots.
3Productivity
If the laser beam is focused to a single spot, then the optics remain simple, but the fragmentation efficiency is limited
Solution Approach 1:
The patent uses a compound lens system that divides the single incoming laser beam into two separate focal spots within the target tissue. This segmentation allows simultaneous fragmentation at two locations, effectively doubling the fragmentation efficiency without requiring two separate laser sources or complex scanning modifications.
Solution Approach 2:
The patent introduces a beam splitter as an intermediary optical element that divides the laser beam into two paths, each leading to a separate focal point. This intermediary component enables enhanced fragmentation efficiency while maintaining compatibility with existing laser engines and scanners, avoiding the need for system-wide redesign.
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
The system effectively doubles the laser repetition rate and enhances fragmentation efficiency, reducing procedure times by up to 50% while maintaining precision and minimizing shadowing effects, and can be easily reconfigured for different ophthalmic procedures.
Implementation Method 1
a birefringent lens. The compound lens is arranged to receive the scanned beam and configured to split each laser pulse of the scanned beam into an ordinary pulse and an extraordinary pulse
Data Source
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Figure 3A
AI summary
An ophthalmic laser system includes a laser engine to generate a beam of femtosecond laser pulses, a laser scanner to scan each laser pulse of the beam in three dimensions according to a scan pattern, and a compound lens comprising a glass lens and a birefringent lens, the compound lens arranged to receive the scanned beam and configured to split each laser pulse of the scanned beam into an ordinary pulse and an extraordinary pulse, producing an ordinary beam comprising ordinary pulses and an extraordinary beam comprising extraordinary pulses.