Microwave Skin Treatment Apparatus with Waveguide Shielding

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Solution Overview

Problem

Existing skin treatment technologies using RF electromagnetic radiation and laser light face challenges in predicting and controlling the depth of heating, leading to uneven and unpredictable heating effects, which can cause hotspots and disrupt the healing process.

Innovation Solution

A skin treatment apparatus utilizing microwave frequency electromagnetic energy delivered through a waveguide with a microwave shield and cooling medium to achieve controlled, uniform heating or ablation at a predetermined depth below the skin surface, protecting the epidermis while targeting the dermis for treatments like skin tumors and collagen shrinkage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of moving object

If RF electromagnetic radiation is used for skin heating, then deep penetration into skin is achieved, but the depth of heating becomes difficult to predict and control

Engineering Contradiction:
Improvedepth of heating penetrationVSAvoidpredictability of heating depth
Core Design Contradiction:
Length of moving objectVSMeasurement precision

Solution Approach 1:

The patent changes the frequency parameter of electromagnetic radiation from RF range to microwave range (2.45 GHz specifically). This parameter change fundamentally alters the heating mechanism from dielectric heating with deep unpredictable penetration to a mechanism where the skin effect confines heating to a predictable depth determined by the skin depth formula, which is controllable through frequency selection

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent replaces the RF dielectric heating mechanism with microwave frequency electromagnetic heating that exploits the skin effect. This substitution changes the fundamental physics from volume-based dielectric heating to surface-confined heating where the effective depth is determined by electromagnetic penetration depth rather than thermal conduction, enabling precise depth control

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Temperature

If laser light is used for skin heating, then heating is concentrated in a small region, but hotspots are generated causing uneven heating

Engineering Contradiction:
Improveheating concentrationVSAvoiduniformity of heating
Core Design Contradiction:
TemperatureVSManufacturing precision

Solution Approach 1:

The patent changes the frequency parameter from laser (visible/near-infrared) to microwave frequency (2.45 GHz). This parameter change transforms the heating pattern from highly concentrated laser spots that create hotspots through localized absorption, to a more distributed microwave field that penetrates and heats tissue more uniformly while still maintaining depth control through the skin effect

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent applies microwave energy in a manner that creates different heating characteristics at different depths - the skin effect naturally creates a gradient where heating is most intense at the surface and decreases with depth, allowing controlled heating of specific layers without creating damaging hotspots that would occur with focused laser energy

Inventive Principle:
Principle #3Local quality

3Object-affected harmful factors

If cooling is applied to skin surface to prevent damage, then surface protection is achieved, but the conduction of heat is disrupted reducing heating effect

Engineering Contradiction:
Improvesurface damage preventionVSAvoidheating effect reduction
Core Design Contradiction:
Object-affected harmful factorsVSLoss of energy

Solution Approach 1:

The patent changes the heating mechanism from thermal conduction-dependent RF or laser heating to microwave frequency heating that exploits the skin effect. This parameter change allows the heating to be primarily electromagnetic in nature rather than relying on thermal conduction, so that surface cooling does not significantly reduce the heating effect at depth. The microwave energy directly heats the tissue through dielectric loss rather than requiring heat conduction from the surface

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses the skin effect itself as a natural intermediary that confines microwave energy to a specific penetration depth. This intermediary mechanism allows selective heating of subsurface tissue while the surface cooling serves its protective function without significantly interfering with the primary heating mechanism, as the heating occurs through electromagnetic energy absorption rather than thermal conduction

Inventive Principle:
Principle #24Intermediary (Mediator)

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 apparatus provides predictable and repeatable heating effects, enhancing the effectiveness of skin treatments by ensuring consistent penetration and minimizing damage to the skin's surface, thereby improving the healing process and treatment outcomes.

Implementation Method 1

a microwave source for generating microwave frequency electromagnetic energy

Methodology Applied
Scientific EffectMicrowave frequency electromagnetic energy: Microwave Radiation

Implementation Method 2

Skin appears as a dielectric medium to RF radiation. When RF radiation passes through the skin, heat is generated at and beneath the surface of the skin tissue.

Methodology Applied
Scientific EffectDielectric heating: Dielectric Heating

Implementation Method 3

Cooling can, for example, be achieved through the use of cryogenic sprays or thermo-electric cooling using Freon, tetrafluoroethane or other such refrigerants.

Methodology Applied
Scientific EffectThermo-electric cooling: Peltier Effect

Implementation Method 4

Cooling can, for example, be achieved through the use of cryogenic sprays

Methodology Applied
Scientific EffectCryogenic cooling: Cryogenics

Implementation Method 5

an applicator for mounting over a region of skin, the applicator comprising: an energy delivery structure for conveying the microwave electromagnetic energy

Methodology Applied
Scientific EffectWaveguide propagation: Waveguide

Data Source

PatentEP3756605B1Skin treatment apparatus
Publication Date: 2023.08.02 UNIV OF WALES BANGOR
  • EP3756605B1 patent drawingFigure 1
  • EP3756605B1 patent drawingFigure 2~3
  • EP3756605B1 patent drawingFigure 4

AI summary

Skin treatment apparatus comprising an energy applicator structure configured to establish heating or ablation at a predetermined and controllable (i.e. selectable) depth below a surface of skin tissue with which it is in contact. The applicator structure may receive a cooling medium and microwave frequency electromagnetic energy, which provide a combined treatment effect that results in heating or ablation in a zone beneath the skin surface. The applicator may be a waveguide (e.g. waveguide horn antenna) with internal shielding configured to provide a substantially uniform heating effect. The applicator may include a thermal camera to monitor treatment.