Picosecond Laser Apparatus for Tattoo Removal

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Solution Overview

Problem

Current systems capable of delivering short pulse duration and high energy laser pulses for treating skin pigmentations, such as tattoos, are complex and expensive, making them impractical for widespread use.

Innovation Solution

A method and apparatus for generating pulsed laser energy with pulse durations of up to 500 picoseconds and energy outputs of 200 to 800 millijoules per pulse, utilizing a resonator with a Pockels cell and polarizer to achieve photomechanical disruption of pigment particles, eliminating the need for multiple lasers and additional modelocking devices.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If current systems capable of delivering short pulse duration and high energy laser pulses are used for treating skin pigmentations, then photomechanical disruption of pigment particles is achieved, but device complexity and cost increase significantly

Engineering Contradiction:
Improvephotomechanical disruption effectivenessVSAvoidsystem complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines the modelocking function and amplification function into a single laser apparatus. The modelocking mechanism generates short pulse durations (picosecond range) while the same apparatus amplifies these pulses to high energy levels (hundreds of millijoules), eliminating the need for separate lasers and amplifier stages required by conventional systems

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The laser apparatus performs multiple functions simultaneously: it generates modelocked pulses with picosecond duration, amplifies these pulses to high energy, and delivers them for photomechanical disruption of pigment particles. This multi-functional design replaces what previously required multiple specialized devices

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

2Power

If multiple lasers and amplifier stages are used to achieve short pulse duration and high energy output, then sufficient energy for photomechanical disruption is obtained, but the system becomes too complex and expensive for practical use

Engineering Contradiction:
Improvelaser energy outputVSAvoidnumber of laser stages
Core Design Contradiction:
PowerVSDevice complexity

Solution Approach 1:

The patent merges the modelocking stage and amplification stage into a single integrated laser apparatus. The modelocking mechanism establishes picosecond pulse duration while the same apparatus amplifies these pulses to high energy levels, eliminating the need for multiple separate laser stages and amplifier components

Inventive Principle:
Principle #5Merging (Combining)

3Productivity

If conventional laser systems with multiple components are deployed, then high energy pulses can be generated, but the cost and complexity make them impractical for widespread tattoo removal applications

Engineering Contradiction:
Improvetreatment effectivenessVSAvoidsystem cost
Core Design Contradiction:
ProductivityVSEase of manufacture

Solution Approach 1:

The patent combines multiple functional components into a single laser apparatus that performs modelocking, pulse amplification, and delivery. This integration reduces the number of components that need to be manufactured, assembled, and maintained, thereby reducing overall system cost while preserving treatment effectiveness

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The laser apparatus serves multiple purposes: generating picosecond pulses, amplifying them to high energy, and delivering them for pigment particle disruption. This multi-functionality eliminates the need for separate specialized devices, reducing manufacturing complexity and cost

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 solution effectively disrupts and removes pigment particles through photomechanical processes, facilitating efficient treatment of tattoos and other skin lesions with reduced complexity and cost, utilizing a simplified apparatus that generates high-energy pulses suitable for photomechanical treatment.

Implementation Method 1

A method and apparatus for generating pulsed laser energy with pulse durations of up to 500 picoseconds and energy outputs of 200 to 800 millijoules per pulse, utilizing a resonator with a Pockels cell and polarizer

Methodology Applied
Scientific EffectPockels effect: Pockels Effect

Implementation Method 2

The use of even shorter pulses, however, results in a change from photothermal to photomechanical processes. The latter mechanism is invoked by applying laser pulses having a duration that is below the acoustic transit time of a sound wave through targeted particles. This causes pressure to build up in the particles

Methodology Applied
Scientific EffectPhotomechanical effect:

Data Source

PatentEP3985810B1Method for the use of a picosecond laser apparatus for removing skin tattoos
Publication Date: 2024.10.16 CYNOSURE INC
  • EP3985810B1 patent drawingFigure 1
  • EP3985810B1 patent drawingFigure 2
  • EP3985810B1 patent drawingFigure 3A~3B

AI summary

Apparatuses and methods are disclosed for applying laser energy having desired pulse characteristics, including a sufficiently short duration and/or a sufficiently high energy for the photomechanical treatment of skin pigmentations and pigmented lesions, both naturally-occurring (e.g., birthmarks), as well as artificial (e.g., tattoos). The laser energy may be generated with an apparatus having a resonator with the capability of switching between a modelocked pulse operating mode and an amplification operating mode. The operating modes are carried out through the application of a time-dependent bias voltage, having waveforms as described herein, to an electro-optical device (e.g., a Pockels cell) positioned along the optical axis of the resonator.