Hair Removal Beam Position Correction Using Optical Feedback

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Solution Overview

Problem

Existing laser hair removal devices face errors between theoretical and actual irradiation positions due to mechanical factors, leading to ineffective hair treatment.

Innovation Solution

A hair removal device with an irradiation position control mechanism, imaging unit, and deviation amount detection unit to correct the actual irradiation position, using correction tables and statistical processing to ensure accurate light guidance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Extent of automation

If laser light is guided to a scheduled irradiation position using a mechanical control mechanism, then the irradiation process can be automated and directed to specific hair targets, but mechanical errors cause deviation between the scheduled position and actual irradiation position

Engineering Contradiction:
Improveautomated irradiation guidanceVSAvoidirradiation position accuracy
Core Design Contradiction:
Extent of automationVSManufacturing precision

Solution Approach 1:

The patent implements a feedback mechanism where an imaging unit captures the actual position of emitted laser light, compares it with the scheduled irradiation position, and automatically corrects deviations by adjusting the irradiation position control mechanism. This closed-loop control system continuously monitors and compensates for mechanical errors, maintaining high positioning accuracy despite automation.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent replaces purely mechanical position control with an optical feedback system. Instead of relying solely on mechanical precision of the irradiation position control mechanism, the system uses optical imaging to detect actual light position and automatically compensates for mechanical deviations, substituting mechanical precision requirements with optical measurement and automated correction.

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

2Productivity

If the entire skin is irradiated with strong light to cover all body hairs, then all hairs in the treatment area can be targeted, but treatment efficiency is poor and skin damage risks increase

Engineering Contradiction:
Improvehair removal efficiencyVSAvoidskin damage risk
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent applies local quality by determining optimal irradiation conditions (wavelength, intensity, pulse duration) based on local characteristics of each treatment area, including skin type, hair color, and hair thickness. This allows precise targeting of hairs with customized light parameters, improving efficiency while minimizing skin damage by avoiding uniform over-irradiation of entire skin areas.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent performs preliminary imaging and analysis of the treatment area to identify hair positions, skin characteristics, and optimal irradiation parameters before emitting laser light. This preliminary assessment enables precise targeting of only the necessary areas, improving treatment efficiency while reducing unnecessary skin exposure and damage risks.

Inventive Principle:
Principle #10Preliminary action

3Device complexity

If laser irradiation parameters are fixed regardless of hair root thickness, hair color, or skin characteristics, then the device structure is simple, but treatment effectiveness is not optimal

Engineering Contradiction:
Improveirradiation parameter controlVSAvoidhair removal effectiveness
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent implements dynamic parameter adjustment where irradiation conditions (wavelength, intensity, pulse duration) are automatically modified based on real-time detection of hair root thickness, hair color, and skin characteristics. This dynamic adaptation optimizes treatment effectiveness for each specific case while maintaining a relatively simple device structure through automated control algorithms.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes irradiation parameters (wavelength, intensity, pulse duration) according to detected hair and skin characteristics. By automatically adjusting these parameters based on imaging data, the system achieves optimal treatment effectiveness for varying hair types and skin conditions without requiring complex manual intervention or overly complicated device architecture.

Inventive Principle:
Principle #35Parameter changes

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

Ensures reliable and precise irradiation of hairs with beam light, improving treatment efficiency and reducing skin damage risks.

Implementation Method 1

an imaging unit configured to be able to image a predetermined region including the light emitted toward the irradiation scheduled position

Methodology Applied
Scientific EffectLight emission and detection: Light

Data Source

PatentEP4289378B1Hair removal device and irradiation position correction method
Publication Date: 2026.04.01 EIDEA INC
  • EP4289378B1 patent drawingFigure 1~2
  • EP4289378B1 patent drawingFigure 3
  • EP4289378B1 patent drawingFigure 4A~4B

AI summary

A hair removal device that performs hair removal treatment using light emitted from a light source, the hair removal device including: a light source unit including the light source; an irradiation position control mechanism configured to guide the light emitted from the light source unit to an irradiation scheduled position; an imaging unit configured to be able to image a predetermined region including the light emitted toward the irradiation scheduled position; and an irradiation position deviation amount detection unit configured to detect an irradiation position deviation amount between the irradiation scheduled position and a real irradiation position of the light, the hair removal device being configured to correct a guide position of the light by the irradiation position control mechanism by using the irradiation position deviation amount detected by the irradiation position deviation amount detection unit.