Acne Laser System Flat Top Beam Shaping
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Solution Overview
Problem
Current laser systems for acne treatment emit wavelengths that are not optimal for selective photothermolysis, leading to thermal heating of surrounding tissues and potential damage, and existing solutions are limited by power and intensity distribution issues, as well as the need for cryogen cooling.
Innovation Solution
A laser system emitting at 1726 nm with a flat top intensity distribution and sufficient power (>30 W) to achieve a fluence of 50 J/cm², ensuring selective treatment of sebaceous glands without cryogen gas, using a combination of optical fibre laser sources and an optical fibre combiner to transform Gaussian to flat top intensity profiles, ensuring stable fluence and adequate penetration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If laser systems operate at conventional wavelengths (585-595 nm, 1450 nm, 1540 nm), then the treatment can be performed with existing devices, but the absorption coefficient of water exceeds that of lipids causing thermal heating of surrounding tissues and potential damage
Solution Approach 1:
The patent changes the fundamental parameter of laser wavelength from conventional values (585-595 nm, 1450 nm, 1540 nm) to the specific range of 1690-1750 nm, where the absorption coefficient of lipids exceeds that of water. This parameter change enables selective photothermolysis of sebaceous glands while minimizing thermal damage to surrounding tissues.
2Object-affected harmful factors
If cryogen spray cooling is used to protect surrounding tissue, then thermal damage is reduced, but the device operation and control are considerably complicated and costs increase
Solution Approach 1:
The patent extracts and eliminates the cryogen spray cooling system from the laser device, achieving thermal protection of surrounding tissues through wavelength selection alone. By operating at 1690-1750 nm where lipid absorption exceeds water absorption, the system inherently protects surrounding tissues without requiring additional cooling mechanisms, thereby simplifying device operation and control.
3Reliability
If existing Raman Fiber Laser sources are used, then laser radiation at 1708 nm can be produced, but the power output (maximum 30 W) is insufficient to guarantee effective treatment of sebaceous glands
Solution Approach 1:
The patent merges multiple Raman Fiber Laser sources (at least two, preferably three or more) to achieve the required power output for effective acne treatment. By combining the output of multiple 30 W sources, the system reaches the necessary power levels while maintaining the optimal wavelength for selective lipid photothermolysis.
4Ease of manufacture
If laser beam has Gaussian intensity distribution, then the laser source is simpler to implement, but the intensity distribution is not uniform causing uneven treatment and potential hot spots
Solution Approach 1:
The patent introduces a beam shaping optical system as an intermediary between the Gaussian laser source and the treatment area. This system transforms the Gaussian intensity profile into a flat-top profile, ensuring uniform energy distribution across the treatment field and eliminating hot spots while maintaining system implementability.
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 reduces thermal damage to surrounding tissues, increases penetration depth, and minimizes side effects like erythema and hyperpigmentation, while maintaining stable fluence and depth over time, ensuring effective acne treatment without cryogen-induced thermal shocks.
Implementation Method 1
the absorption coefficient of the lipids, found in abundance in the sebaceous gland, is lower than the absorption coefficient of water... In the spectral region ranging from 1690 nm to 1750 nm. In particular at 1726 nm the absorption coefficient of the lipids is 10 cm−1 while the absorption coefficient of the water is 5 cm−1
Implementation Method 2
Due to the phenomenon of selective photothermolysis (Selective Photothermolysis: Precise Microsurgery by Selective Absorption of Pulsed Radiation, Science, 220:524-527 1983), the sebaceous gland must be reached by a dose of energy (fluence) for a time not exceeding the heat diffusion time, 0.1 sec, and such as to induce a temperature increase sufficient enough to destroy it without causing damage to the surrounding tissues
Implementation Method 3
using a combination of optical fibre laser sources and an optical fibre combiner to transform Gaussian to flat top intensity profiles
Implementation Method 4
A laser system emitting at 1726 nm with a flat top intensity distribution and sufficient power (>30 W) to achieve a fluence of 50 J/cm², ensuring selective treatment of sebaceous glands
Data Source
AI summary
A laser system for selective treatment of acne comprising: at least two laser sources (10) having wavelength ranging from 1690 to 1750 nm which supply a first and a second laser beam respectively; a first multi-mode optical fibre (18) having a length equal to or greater than 5 m receiving said first laser beam; a second multi-mode optical fibre (18) having a length equal to or greater than 5 m receiving said second laser beam; an optical combiner (20) receiving said first and second optical fibre (18) and supplying a third laser beam to a third optical fibre (21); said third optical fibre (21) having a length equal to or greater than 5 m; said third optical fibre (21) receives said third laser beam and supplies, at its output, a fourth laser beam; a fourth optical fibre (24) which receives said fourth laser beam; a handpiece (27) associated with said fourth optical fibre (24); said fourth laser beam having a distribution intensity variance lower than or equal to 15% with respect to the mean rated value, a diameter greater than 2.5 mm, and a maximum available fluence greater than 30 J/cm2.