Pulsed Laser System for Dermatology Using Temporal Modulation

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Solution Overview

Problem

Current dermatological laser systems face limitations in spatial resolution, are invasive, and pose risks of ablation and heating due to long, energetic pulses with low repetition frequencies, requiring multiple systems for various treatments.

Innovation Solution

A pulsed laser system with ultra-brief pulses (100 fs to 100 ps) at high repetition frequencies (1 kHz to 10 GHz), incorporating temporal and spatial modulation using acousto-optic modulators and beam scanning devices to reduce energy density on the skin, allowing for precise targeting and reduced heating.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If long, energetic laser pulses are used for dermatological treatment, then the laser can effectively treat various skin conditions, but the spatial resolution is limited and the risk of ablation and heating increases

Engineering Contradiction:
Improvetreatment effectivenessVSAvoidspatial resolution
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The patent segments the laser pulse in time by using high repetition frequency pulses (1 kHz to 10 GHz) with ultra-brief duration (100 fs to 100 ps), dividing the treatment into many short pulses rather than using few long pulses. This temporal segmentation allows precise spatial control while maintaining treatment effectiveness

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent employs periodic action through high repetition frequency laser pulses, delivering energy in rapid succession at controlled intervals. This periodic delivery enables cumulative heating effects for treatment effectiveness while the short pulse duration prevents excessive localized heating and ablation

Inventive Principle:
Principle #19Periodic action

2Manufacturing precision

If the laser spot is focused to increase spatial resolution, then the spatial resolution improves, but the laser intensity increases which further increases the risk of heating

Engineering Contradiction:
Improvespatial resolutionVSAvoidheating risk
Core Design Contradiction:
Manufacturing precisionVSTemperature

Solution Approach 1:

The patent maintains continuity of useful action by using high repetition frequency pulses that continuously deliver energy to the treatment area. This continuous action at high frequency allows the laser to maintain focused spatial resolution while the rapid pulse succession distributes thermal energy, preventing excessive temperature buildup at any single point

Inventive Principle:
Principle #20Continuity of useful action

Solution Approach 2:

The patent changes key parameters: pulse duration (ultra-brief 100 fs to 100 ps), repetition frequency (1 kHz to 10 GHz), and energy per pulse (≤10 microjoules). These parameter changes enable the laser to achieve high spatial resolution through focusing while the ultra-brief duration and high repetition rate control the thermal accumulation, reducing heating risk

Inventive Principle:
Principle #35Parameter changes

3Reliability

If low repetition rate laser pulses are used, then the energy per pulse can be high for effective treatment, but multiple treatment sessions are required reducing productivity

Engineering Contradiction:
Improvetreatment effectivenessVSAvoidnumber of treatment sessions
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent implements continuity of useful action through high repetition frequency pulsing, delivering many low-energy pulses in rapid succession (1 kHz to 10 GHz). This continuous energy delivery accumulates the therapeutic effect within a single treatment session, eliminating the need for multiple sessions and significantly improving productivity while maintaining treatment effectiveness

Inventive Principle:
Principle #20Continuity of useful action

4Adaptability or versatility

If a single laser system is designed to handle various dermatological treatments, then versatility improves, but the system complexity increases

Engineering Contradiction:
Improvetreatment varietyVSAvoidsystem complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent applies universality by designing a single laser system capable of performing multiple dermatological treatments including hair removal, skin rejuvenation, pigment spot removal, and tattoo removal. The high repetition frequency ultra-brief pulse technology serves as a universal mechanism that can be adapted to different treatment types by adjusting parameters such as wavelength, pulse energy, and scanning patterns, rather than requiring separate specialized systems for each application

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 achieves improved spatial resolution, reduced risk of heating, and increased efficiency with a single system capable of various dermatological treatments, focusing energy on a smaller area while maintaining safety and effectiveness.

Implementation Method 1

the time modulation means for the laser pulse beam include an acousto-optic modulator and an electrical generator, the acousto-optic modulator being disposed at the output of an optical amplifier system, the electrical generator being adapted to generate a radio-frequency signal applied to the electrodes of the acousto-optic modulator

Methodology Applied
Scientific EffectAcousto-optic effect: Acousto-optic Effect

Implementation Method 2

the optical amplifier system includes an optical pumping device and a current-voltage source

Methodology Applied
Scientific EffectOptical pumping:

Implementation Method 3

the use of laser pulses has many applications in the scientific, industrial, and medical fields. In dermatology, different lasers are used for many applications such as hair removal, skin rejuvenation, removal of pigment spots or tattoos

Methodology Applied
Scientific EffectPhotothermal effect:

Implementation Method 4

Most currently available lasers suitable for dermatological applications generate long, energetic pulses that induce a thermal photoablation effect

Methodology Applied
Scientific EffectPhotoablation: Laser Ablation

Data Source

PatentEP3849658B1Pulsed laser system for dermatological treatments
Publication Date: 2023.10.25 IRISIOME
  • EP3849658B1 patent drawingFigure 1~3
  • EP3849658B1 patent drawingFigure 4~7
  • EP3849658B1 patent drawingFigure 8

AI summary

The invention relates to a pulsed laser system for dermatological treatment, comprising a light source (1) suitable for emitting a light pulse beam (10) and an optical amplifier system (2) suitable for generating a laser pulse beam (20) at a first repetition frequency (F1). According to the invention, the duration (d) of a laser pulse (20) is between 100 femtoseconds and 100 picoseconds, the first repetition frequency (F1) is between 1 kHz and 10 GHz, each laser pulse having a quantity of energy less than or equal to 1 microjoule, and the pulsed laser system also comprises means for the temporal modulation of the laser pulse beam (20) and/or means for the spatial modulation of the laser pulse beam (20), said temporal and/or spatial modulation means being suitable for reducing the density of energy deposited on a surface to be treated and for generating a density of energy of between 0.0001 J/cm² and 0.01 J/cm².