Diffractive Optical Elements for Fractional Skin Treatment

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Solution Overview

Problem

Fractional laser treatments with diffractive beam splitters are effective for generating zones of injury promoting neocollagenesis and improving wrinkles but have limited tissue coverage for pigmentation, as highly focused beams provide less than 5% coverage.

Innovation Solution

Combining an axicon diffractive optic with a diffractive beam splitter to create coaxial laser beams with ring-shaped and central energy distributions, allowing adjustable ratios of energy distribution to enhance tissue coverage for pigmentation while maintaining focused beams for wrinkle treatment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If highly focused laser beams are used for fractional skin treatment, then wrinkle treatment effectiveness is improved, but tissue coverage for pigmentation deteriorates (less than 5% coverage)

Engineering Contradiction:
Improvewrinkle treatment effectivenessVSAvoidtissue coverage area
Core Design Contradiction:
Manufacturing precisionVSArea of stationary object

Solution Approach 1:

The laser beam is segmented into multiple beamlets arranged in a matrix pattern, where each beamlet provides focused treatment. This segmentation allows the system to cover a larger treatment area while maintaining focused beam characteristics for wrinkle treatment effectiveness.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention transitions from single-beam or simple array patterns to a two-dimensional matrix arrangement of beamlets. This dimensional expansion increases the covered tissue area while preserving the focused nature of individual beams through proper optical design.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Manufacturing precision

If diffractive beam splitter is used to generate multiple beamlets, then wrinkle treatment is improved, but pigmentation treatment coverage remains limited

Engineering Contradiction:
Improvewrinkle treatment precisionVSAvoidtreatment versatility for different skin issues
Core Design Contradiction:
Manufacturing precisionVSAdaptability or versatility

Solution Approach 1:

Different regions of the treatment pattern provide different quality characteristics. The matrix of beamlets creates zones with varying fluence and spot sizes, allowing simultaneous optimization for wrinkle treatment (focused beams) and pigmentation treatment (broader coverage areas) within the same treatment field.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The optical system is designed to perform multiple functions: treating wrinkles through focused beam delivery and treating pigmentation through expanded tissue coverage. The same beam splitting and focusing mechanism adapts to address different dermatological concerns with a single device configuration.

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

3Manufacturing precision

If lens is placed after diffractive beam splitter to focus beams, then focused spots are achieved, but separation angle and spot pitch are fixed by design

Engineering Contradiction:
Improvespot focusing precisionVSAvoidadjustability of treatment parameters
Core Design Contradiction:
Manufacturing precisionVSAdaptability or versatility

Solution Approach 1:

The optical system incorporates adjustable elements that allow dynamic modification of beam separation angles and spot pitches. This enables the treatment pattern to be adapted for different clinical indications, skin types, and treatment depths while maintaining precise focusing through controllable optical parameters.

Inventive Principle:
Principle #15Dynamics

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 combination improves tissue coverage for pigmentation while maintaining effective treatment of wrinkles and fine lines, allowing for a single treatment session to address both issues with adjustable treatment areas and fluence.

Implementation Method 1

One of the diffractive optical elements (DOE) such as an axicon, provides two coaxial laser beams. One of the laser beams has a ring cross section and the other coaxial laser beam is a central beam

Methodology Applied
Scientific EffectDiffraction: Diffraction

Implementation Method 2

Another diffractive optical element such as a beam splitter, splits the two coaxial laser beams into a plurality of beamlets

Methodology Applied
Scientific EffectDiffraction: Diffraction

Implementation Method 3

A lens arranged to receive the plurality of the laser beams and to focus them in a skin treatment plane

Methodology Applied
Scientific EffectOptical focusing: Focusing

Data Source

PatentEP3391938B1A device for skin treatment
Publication Date: 2021.03.17 CANDELA CORP
  • EP3391938B1 patent drawingFigure 1~2
  • EP3391938B1 patent drawingFigure 3~4

AI summary

A device and a method for fractional skin treatment. The device employs two diffractive optical elements. One of the diffractive optical elements provides two coaxial laser beams and another diffractive optical element splits the two coaxial laser beams into a plurality of beamlets. A lens arranged to receive the plurality of the laser beams and to focus them in a skin treatment plane. The lens forms an image where each of the beamlets is imaged as a spot with a high intensity central area and a lower intensity area surrounding the central area.