Laser Beam Direct Measurement and Error Budget
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Solution Overview
Problem
Refractive laser systems face challenges in maintaining the uniformity, size, and position of laser pulses during corneal ablation procedures, leading to deviations from desired treatment outcomes due to factors like humidity, plume effects, and laser hardware variability.
Innovation Solution
A beam splitter directs a fraction of the laser beam to UV light sensors for real-time monitoring of pulse profile, size, and position, allowing for feedback-controlled adjustments to ensure accurate delivery of subsequent pulses, using a beam profiler and processor to refine treatment plans based on measured parameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If real-time monitoring of laser beam parameters is implemented using beam splitters and UV sensors, then measurement precision and treatment accuracy are improved, but device complexity increases
Solution Approach 1:
A beam splitter is introduced as an intermediary component to divide the laser beam into two paths: one for treatment and one for real-time monitoring. This mediator enables simultaneous measurement of beam parameters (position, size, shape, uniformity) without interfering with the primary treatment function, resolving the contradiction between measurement precision and device complexity by adding a dedicated monitoring pathway rather than modifying the treatment system itself.
Solution Approach 2:
The system creates an optical copy of the laser beam through the beam splitter, directing a portion of the beam to UV sensors that generate electrical signals representing the beam's characteristics. This copying approach allows real-time monitoring of all critical parameters without requiring direct physical measurement at the treatment site, improving measurement precision while keeping the added complexity manageable through standardized sensor components.
2Reliability
If feedback control systems are added to compensate for laser pulse deviations, then treatment reliability is improved, but device complexity increases
Solution Approach 1:
A feedback control loop is implemented where UV sensors continuously monitor laser beam parameters during treatment, compare measured values against target specifications, and generate corrective signals to adjust subsequent pulses. This feedback mechanism compensates for deviations in position, size, shape, and uniformity caused by environmental factors (humidity, plume effects) or hardware variability, significantly improving treatment reliability while using established control algorithms to manage system complexity.
Solution Approach 2:
The system performs self-correction by automatically adjusting laser delivery parameters based on real-time measurements without requiring external intervention. The feedback control system monitors its own performance and makes autonomous adjustments to maintain treatment consistency, improving reliability while reducing the need for complex manual calibration and monitoring systems.
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 approach enables real-time compensation for energy fluctuations and position deviations, improving the predictability and accuracy of laser delivery, thereby enhancing clinical outcomes in refractive surgery.
Implementation Method 1
A beam splitter directs a fraction of the laser beam to UV light sensors for real-time monitoring of pulse profile, size, and position
Implementation Method 2
delivering a portion of the first laser pulse to a beam profiler and measuring a pulse profile of the first laser pulse with the beam profiler
Implementation Method 3
The camera-based imager may include a UV-to-visible converter plate, an image sensor, and a lens for focusing fluorescing light from a back of the UV-to-visible converter plate onto the image sensor
Data Source
AI summary
Embodiments of the present invention generally describe systems, devices, and methods for directly measuring pulse profiles during pulse delivery. In some embodiment, the pulse profiles may be measured while the pulse is delivered to ablate a material. Embodiments, may calculate ablation spot parameters based on the pulse profiles and may refine one or more subsequent laser pulses based on deviations from the calculated ablation spot parameters from desired ablation spot parameters. In some embodiments, a fluence profiler is provided. The fluence profiler may measure a pulse profile of a laser pulse from a portion of the laser pulse. The fluence profiler may utilize a UV radiation energy sensor device and a camera-based imager. The measurements from the UV radiation energy sensor device and the camera-based imager may be combined and scaled to provide a measured pulse profile that corresponds to the delivered pulse.