Laser Pulse Energy Detection Circuitry for Eye Surgery
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Solution Overview
Problem
Existing methods for cutting materials, such as tissue during eye surgery, often result in rougher surfaces and require cumbersome patient interfaces, leading to increased intraocular pressure and variability in tissue cutting.
Innovation Solution
The development of an improved laser system that includes a pulsed laser, a scanning module for precise optical breakdown control, and energy detector circuitry to accurately measure the energy of each pulse, allowing for adjustments to improve treatment accuracy and repeatability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If mechanical cutting tools (chisels, knives, scalpels) are used to cut tissue, then the cutting process is simple and direct, but the surface quality becomes rougher and less ideal
Solution Approach 1:
The patent replaces mechanical cutting tools with a pulsed laser system that uses optical breakdown to cut tissue. The laser delivers high peak power pulses that create plasma channels through optical breakdown, enabling precise cutting without mechanical contact. This substitution of mechanical energy with optical energy allows for smoother surfaces and more precise control while maintaining cutting effectiveness.
2Productivity
If short pulsed lasers with very high pulse repetition rates are used to cut tissue, then cutting speed is improved, but energy measurement becomes difficult and less accurate
Solution Approach 1:
The patent divides the detection of high repetition rate laser pulses into multiple discrete time bins using a multi-channel detector system. Each detector channel is assigned to a specific time window, allowing the system to resolve and measure individual pulses even at very high repetition rates. This temporal segmentation enables accurate energy measurement of each pulse while maintaining high productivity.
Solution Approach 2:
The patent employs dynamic timing adjustments and flexible detector gating that can adapt to different pulse repetition rates. The system dynamically configures its detection windows and integration times to match the laser pulse characteristics, enabling accurate measurement across a wide range of operating conditions while maintaining high cutting speed.
3Device complexity
If conventional laser energy monitoring is used, then the system is simpler, but treatment accuracy and repeatability are reduced
Solution Approach 1:
The patent implements a feedback system where the energy of each laser pulse is measured by the detector and used to adjust subsequent pulses. The system monitors pulse-to-pulse energy variations and provides real-time feedback to the laser control, enabling automatic compensation for energy drift and ensuring consistent treatment accuracy. This closed-loop control significantly improves reliability while maintaining reasonable system complexity.
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 more accurate and repeatable energy measurement of pulsed lasers, reducing reliance on patient interfaces, minimizing gas formation during laser cutting, and achieving smoother, more uniform cuts in tissue.
Implementation Method 1
A first light energy detector 76A to measure laser beam energy and a second light energy detector 76B to measure laser beam energy
Implementation Method 2
A first integrator 232 and a second integrator 234 in the energy detector circuitry 230
Data Source
AI summary
A photo detector is selectively coupled to a first integrator or a second integrator with switching circuitry when the laser pulses. An integration time of the signal from the photo detector can be substantially greater than an amount of time between successive laser beam pulses in order to provide an accurate measurement of each laser beam pulse of a high repetition rate pulsed laser. The laser may comprise a clock coupled to an optical switch of the laser system, and control circuitry can control switching and coupling of the detector to the first integrator or the second integrator in response to the clock signal. The first integrator and the second integrator can be selectively coupled to an output such that the first integrator or the second integrator is coupled to the output of the energy detection circuitry when the other integrator is coupled to the detector.