Diode Laser Hair Removal Handpiece Thermal Management

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Solution Overview

Problem

Existing diode laser hair removal systems are cumbersome due to bulky cooling circuits, fixed laser power and wavelengths, and lack real-time feedback, leading to inefficient and potentially harmful treatments for both operators and users.

Innovation Solution

A diode laser hair removal system with a handpiece equipped with sensors and a control unit that provides real-time feedback, adjustable laser intensity, and modular wavelength capabilities, using optical fibers for efficient cooling and minimizing heat exposure, while allowing for remote data storage and customizable treatment plans.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a diode laser is mounted in the handpiece for hair removal treatment, then the treatment effectiveness is improved, but the handpiece temperature increases due to heat from the Peltier module and diode, causing discomfort and potential harm to the user

Engineering Contradiction:
Improvetreatment effectivenessVSAvoidhandpiece temperature
Core Design Contradiction:
ReliabilityVSTemperature

Solution Approach 1:

The system divides the laser cooling function into two separate locations: the diode laser is cooled in the control unit through liquid cooling circuits, while the handpiece uses a Peltier module for localized cooling of the treatment area. This segmentation allows each component to be optimized independently for its specific thermal management needs.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces an intermediary cooling system using liquid cooling circuits with inlet and outlet conduits that transfer heat away from the diode laser before it reaches the handpiece. This intermediary cooling mechanism acts as a heat buffer, preventing excessive heat transfer to the user's skin.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Temperature

If liquid cooling circuits are enclosed in the wiring connecting the control unit to the handpiece, then the diode laser can be cooled effectively, but the system complexity and device size increase significantly

Engineering Contradiction:
Improvediode laser coolingVSAvoidcooling circuit complexity
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The patent extracts the diode laser cooling function from the handpiece and relocates it to the control unit. The handpiece wiring is simplified to only include electrical connections and optical fiber for laser beam transmission, while the liquid cooling circuits remain exclusively in the control unit, reducing overall system complexity.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The cooling system is reorganized spatially by separating thermal management functions from the handheld component. The control unit handles all liquid cooling operations for the diode laser, while the handpiece focuses solely on delivering the laser beam and providing localized Peltier cooling, creating a clear functional separation between dimensions.

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

3Device complexity

If the diode laser and Peltier module are integrated in the handpiece, then the system structure is simplified, but the heat from the Peltier module's warm side heats the diode laser source, reducing cooling effectiveness

Engineering Contradiction:
Improvesystem structureVSAvoiddiode laser temperature
Core Design Contradiction:
Device complexityVSTemperature

Solution Approach 1:

The system segments the thermal management functions by location: the diode laser cooling is handled by liquid cooling circuits in the control unit, while the Peltier module for skin cooling is located in the handpiece. This spatial segmentation prevents thermal interference between the two cooling mechanisms.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The liquid cooling circuits act as an intermediary heat transfer system that removes heat from the diode laser at the source (in the control unit) before it can be transferred to the handpiece. This intermediary cooling prevents the warm side of the Peltier module from heating the diode laser.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Reliability

If multiple passages of the handpiece are made on the same skin area to ensure effective hair removal, then the treatment thoroughness is improved, but the user is exposed to excessive heat and potential skin damage

Engineering Contradiction:
Improvetreatment thoroughnessVSAvoidskin heat exposure
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The system incorporates temperature sensors that provide real-time feedback on skin temperature during treatment. This feedback mechanism allows the system to monitor thermal accumulation and adjust treatment parameters or pause between passages to prevent excessive heat buildup while ensuring adequate treatment coverage.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The treatment protocol uses periodic action by alternating between laser application passages and cooling intervals. The Peltier module provides continuous or periodic cooling during and between laser passages, allowing multiple treatments to be administered safely by removing heat between exposures.

Inventive Principle:
Principle #19Periodic action

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 offers a comfortable, efficient, and effective hair removal process with real-time quality assessment, reduced heat exposure, and customizable settings, enhancing treatment precision and user safety.

Implementation Method 1

the handpiece includes, among its internal components, some items comprising Peltier modules, each of them having a cold side facing the patient subject to the treatment, and a warm side facing the inner side of the handpiece itself

Methodology Applied
Scientific EffectPeltier effect: Peltier Effect

Implementation Method 2

there is the need to cool the diode, typically using gas, air or more frequently liquid circuits

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 3

cool the diode, typically using gas, air or more frequently liquid circuits, with a cooling liquid inlet conduit and an outlet conduit for the same liquid

Methodology Applied
Scientific EffectConvection: Convection

Implementation Method 4

System and method for guided hair removal using diode laser

Methodology Applied
Scientific EffectLaser emission: Laser

Data Source

PatentEP4003507B1System and method for guided hair removal using diode laser
Publication Date: 2023.08.30 CHIARIA SIMONE
  • EP4003507B1 patent drawingFigure 1
  • EP4003507B1 patent drawingFigure 2~2b
  • EP4003507B1 patent drawingFigure 3

AI summary

System (100) for guided hair removal using diode laser comprising: a handpiece (102) comprising: one position sensor (103); one haptic transducer (105); a couple of pressure sensors (106); a camera (108); a display (109); and an electronic control board (114) connected to the position sensor (103), to the haptic transducer (105), to the couple of pressure sensors (106), to the camera (108), to the display (109); and a control unit (101) comprising at least one laser diode (101a). The control unit (101) is connected to the handpiece (102) through connection means (110) comprising optical fibers, the couple of pressure sensors (106) is configured to activate a laser emission on a portion of the skin of a user, and the display (109) is configured to visualize the graphical plot of the displacement vector and the position of the handpiece (102) during a laser hair removal treatment.