Wavelength-Selective Mirrors for Flash-Back Reduction in Ophthalmic Lasers
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Solution Overview
Problem
Laser-based ophthalmic treatments face challenges such as lengthy procedures, physician fatigue, patient discomfort, and distracting flash-back light due to unwanted green light leakage, which can be hazardous and uncomfortable for doctors.
Innovation Solution
A laser apparatus that selectively suppresses wavelength components on either side of the target wavelength using coated mirrors or filters, reducing unwanted light to a level comparable to white light illumination, thereby minimizing flash-back and ensuring safety and comfort for doctors during treatments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a laser safety filter is used to block coherent laser light from reaching the doctor, then the doctor is protected from eye damage, but the filter reduces color clarity and makes it difficult to see small color variations on the retina
Solution Approach 1:
The patent applies local quality by using wavelength-selective mirrors with different reflectivity characteristics at different wavelengths. The mirror is designed to reflect the treatment laser wavelength (514-580 nm) while transmitting unwanted flash-back wavelengths (400-500 nm and 600-700 nm), creating localized spectral selectivity that protects the doctor without compromising color clarity.
Solution Approach 2:
The patent changes the spectral parameters of the optical system by introducing mirrors with specific reflectivity curves that vary with wavelength. Instead of using a broad-band filter that uniformly blocks all wavelengths, the system uses wavelength-dependent reflectivity to selectively block only the harmful flash-back wavelengths while preserving the treatment laser and color information.
2Productivity
If multi-spot treatment is used to reduce treatment times, then productivity increases, but the complexity of directing laser energy to multiple locations increases
Solution Approach 1:
The patent segments the treatment process by using multiple independent laser diodes, each capable of delivering laser energy to different retinal locations simultaneously. This segmentation allows parallel treatment of multiple spots, increasing productivity while keeping each individual laser channel simple and independent.
Solution Approach 2:
The patent implements multi-functionality by designing a system where a single laser apparatus can perform both treatment laser delivery and aiming laser functions through wavelength-selective mirrors. The same optical path and delivery system handle multiple wavelengths and multiple treatment locations, reducing overall system complexity while maintaining high productivity.
3Device complexity
If diode lasers are used to generate the treatment laser beam, then the laser apparatus is more compact and cost-effective, but unwanted spontaneous emission light causes distracting flash-back to the doctor
Solution Approach 1:
The patent converts the harmful spontaneous emission light from the diode laser into a beneficial feature by using wavelength-selective mirrors to redirect this light into the delivery path. The mirror design ensures that while the spontaneous emission causes flash-back, the same optical path delivers the treatment laser to the patient's eye, turning the harmful byproduct into part of the therapeutic system.
Solution Approach 2:
The patent changes the spectral parameters by using mirrors with specific reflectivity curves that target the spontaneous emission wavelengths of the diode laser. The mirror reflectivity is optimized to block the harmful flash-back wavelengths while maintaining high transmission of the desired treatment laser wavelengths, thereby controlling the spectral output.
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 solution effectively reduces flash-back light by at least a factor of 5, making treatments less distracting and safer for doctors, while maintaining therapeutic effectiveness and high color clarity for the doctor's view of the retina.
Implementation Method 1
at least one of the one or more mirrors is coated with a coating such that light having the first target wavelength is reflected by the at least one mirror, and light having wavelengths within the first and second suppressing wavelength ranges is transmitted by the at least one mirror
Implementation Method 2
a treatment light source configured to generate a laser beam having a first target wavelength
Implementation Method 3
an aiming light source configured to generate an aiming light beam having a second target wavelength
Implementation Method 4
a laser safety filter is used. This safety filter is designed to block the coherent laser light of the treatment laser beam from reaching the doctor
Implementation Method 5
Laser coagulation requires the exposure of the retina to visible laser light and relies on the selective absorption in melanin and hemoglobin, typically at a wavelength range of 514-580 nanometers (nm), ie. visible green light, to achieve blood vessel coagulation
Data Source
AI summary
A laser apparatus for providing a treatment laser beam for photothermal ophthalmic treatment comprising a treatment light source configured to generate a laser beam having a first target wavelength and having a first output power, an aiming light source configured to generate an aiming light beam having a second target wavelength and having a second output power lower than the first output power wherein the laser apparatus is configured to selectively suppress a set of wavelength components of the laser beam generated by the treatment light source to create a treatment laser beam, the set of wavelength components having wavelengths within a first and/or second suppressing wavelength range, the first and/or second suppressing wavelength ranges being located on respective sides of the first target wavelength, and wherein the laser apparatus is further configured to output the treatment laser beam.