Concave Mirror Illumination for Accurate Skin And Hair Inspection

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Solution Overview

Problem

Existing devices for inspecting human body portions, such as skin or hair, are costly and cumbersome due to the use of multiple lenses to collimate light sources, which are not fully satisfactory.

Innovation Solution

The device employs a concave mirror to reflect and collimate emitted luminous radiation, eliminating the need for individual lenses and reducing cost and bulkiness while providing accurate illumination and good color rendering.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If multiple lenses are used to collimate light from each light source, then accurate inspection is achieved, but device cost and complexity increase

Engineering Contradiction:
Improveinspection accuracyVSAvoiddevice complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent merges the collimation function from multiple individual lenses into a single shared concave mirror that serves all light sources. This consolidation maintains the necessary collimated illumination for accurate inspection while dramatically reducing the number of optical components and overall device complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The concave mirror performs a universal collimation function for multiple light sources simultaneously, rather than requiring dedicated lenses for each source. This multi-functional approach achieves accurate inspection across all illumination points without proportionally increasing component count.

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

2Measurement precision

If multiple lenses are used to collimate light from each light source, then accurate inspection is achieved, but device size increases

Engineering Contradiction:
Improveinspection accuracyVSAvoiddevice size
Core Design Contradiction:
Measurement precisionVSVolume of moving object

Solution Approach 1:

The patent consolidates multiple lens assemblies into a single concave mirror structure, reducing the overall volume occupied by optical components. The shared mirror approach eliminates redundant lens housings and mounting structures, thereby decreasing device size while preserving inspection accuracy.

Inventive Principle:
Principle #5Merging (Combining)

3Measurement precision

If multiple lenses are used to collimate light from each light source, then accurate inspection is achieved, but manufacturing cost increases

Engineering Contradiction:
Improveinspection accuracyVSAvoidmanufacturing cost
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent reduces manufacturing cost by merging multiple lens components into a single concave mirror. This consolidation decreases the number of parts that need to be manufactured, inventoried, and assembled, while also reducing the total optical material required. The single mirror can be manufactured more economically than multiple precision lenses.

Inventive Principle:
Principle #5Merging (Combining)

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 achieves accurate inspection with reduced cost and size, while minimizing specular glare and enhancing color rendering for captured data processing.

Implementation Method 1

the at least one concave mirror being configured to reflect the emitted luminous radiation produced by at least one of the light sources in a reflected luminous radiation

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 2

the reflected luminous radiation being collimated toward the observation window so as to illuminate the human body portion

Methodology Applied
Scientific EffectCollimation: Lens

Data Source

PatentEP4440416B1Device for inspecting a human body portion and associated method
Publication Date: 2026.02.11 LOREAL SA
  • EP4440416B1 patent drawingFigure 1
  • EP4440416B1 patent drawingFigure 2
  • EP4440416B1 patent drawingFigure 3

AI summary

Device for inspecting a human body portion and associated method This device for inspecting a human body portion (12) comprises: - a frame (14), defining an observation window (26); - an optical sensor, configured to capture a measurement luminous radiation (C) from the human body portion (12), and - an illumination arrangement, configured to illuminate the human body portion (12), the illumination arrangement comprising at least one light source (30), each light source (30) being configured to produce an emitted luminous radiation (A). The illumination arrangement comprises at least one concave mirror (32) configured to reflect the emitted luminous radiation (A) produced by at least one of the light sources (30) in a reflected luminous radiation (B), the reflected luminous radiation (B) being collimated toward the observation window (26) so as to illuminate the human body portion (12).