Helmet Visor Frame With LC Layer for Uniform Light Adaptation

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Solution Overview

Problem

Existing protective helmet visors fail to provide rapid and uniform light adaptation to varying ambient conditions due to mechanical stress-induced birefringence and low maximum brightness, especially with GH-type liquid crystal layers, and require bulky batteries for electrochromic solutions.

Innovation Solution

A protective helmet with a GH-type liquid crystal film controlled by an electronic board powered by a photovoltaic cell, integrated into a frame that stabilizes the LC layer against mechanical stress and ensures uniform transparency, combined with a structural lens for optimal light modulation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If GH-type liquid crystal layers are used in helmet visors, then light transmission and transparency are improved, but mechanical stress causes unwanted inhomogeneities and birefringence effects that compromise uniformity

Engineering Contradiction:
Improvelight transmissionVSAvoiduniformity of transparency
Core Design Contradiction:
Illumination intensityVSManufacturing precision

Solution Approach 1:

The patent applies a preliminary counteracting action by introducing a depolarizing filter specifically designed to compensate for and neutralize the birefringence effects and inhomogeneities that arise from mechanical stresses in the GH-type liquid crystal layer. This filter is integrated into the visor assembly before use, preemptively correcting the optical distortions that would otherwise compromise transparency uniformity.

Inventive Principle:
Principle #9Preliminary anti-action

Solution Approach 2:

The patent employs a composite structure combining multiple layers including the GH-type liquid crystal layer, a structural lens, a frame for mechanical support, and a depolarizing filter. This composite assembly works synergistically to maintain both high light transmission and uniform transparency, as each component addresses specific aspects of the optical performance while compensating for the weaknesses of others.

Inventive Principle:
Principle #40Composite materials

2Adaptability or versatility

If electrochromic lenses are used for automatic adaptation to ambient light, then light filtering capability is improved, but bulky batteries are required which increase device complexity

Engineering Contradiction:
Improveautomatic adaptation to ambient lightVSAvoidbulky batteries
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent replaces the electrochromic lens mechanism (which requires bulky batteries and electrical systems) with a mechanically simpler optical system using GH-type liquid crystals combined with a depolarizing filter. This substitution maintains the adaptability function through optical means rather than electrical actuation, thereby eliminating the need for large power sources and reducing overall device complexity.

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

3Adaptability or versatility

If photochromatic lenses are used, then light filtering is achieved, but reaction speed to rapid changes in brightness is too slow

Engineering Contradiction:
Improvelight filteringVSAvoidreaction speed to brightness changes
Core Design Contradiction:
Adaptability or versatilityVSSpeed

Solution Approach 1:

The patent changes the fundamental operating parameter of the optical system from photochemical reaction (in photochromatic lenses) to liquid crystal optical switching controlled by a depolarizing filter. This parameter change enables much faster response times to brightness changes, as the liquid crystal system can be controlled electronically or mechanically without relying on slow photochemical transformation processes.

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

The helmet provides rapid and uniform light adaptation with at least 60% visibility in bright conditions and up to 40% in dark conditions, maintaining comfort and reducing mechanical interference, without the need for bulky batteries.

Implementation Method 1

lenses that use layers of liquid crystals are known, and they are the only ones that are able to react quickly to changes in ambient light

Methodology Applied
Scientific EffectLiquid crystal optical modulation: Liquid Crystals

Implementation Method 2

Electrochromic lenses are known that typically use polymers that may change optical properties when a magnetic field is applied

Methodology Applied
Scientific EffectElectro-optic effect: Electro-Optic Effects

Implementation Method 3

A protective helmet with a GH-type liquid crystal film controlled by an electronic board powered by a photovoltaic cell

Methodology Applied
Scientific EffectPhotovoltaic effect: Photovoltaic Effect

Implementation Method 4

a frame that stabilizes the LC layer against mechanical stress and ensures uniform transparency

Methodology Applied
Scientific EffectMechanical stress resistance:

Implementation Method 5

protection from light is achieved simply through the use of pigments that cause the visor to transmit only a fraction of the incident light

Methodology Applied
Scientific EffectLight absorption and filtering: Absorption (EM radiation)

Data Source

PatentEP4346486B1Protective helmet equipped with visor with frame and LC layer
Publication Date: 2025.12.17 OUT OF SRL
  • EP4346486B1 patent drawingFigure 1~2
  • EP4346486B1 patent drawingFigure 3
  • EP4346486B1 patent drawingFigure 4~5

AI summary

A protective helmet (1) for practicing sports activities or using motorized vehicles, according to the present invention comprises a cap (2) equipped with a front opening (23), at the user's eye region, closed by a visor assembly (3). Said visor assembly (3) comprises: at least one at least partially transparent structural lens (41); a Guest-Host type liquid crystal LC film (43) adapted to modify its own transparency level, arranged behind the structural lens (41); at least one electrical source for powering the LC film (43); a frame (31) suitable for supporting the structural lens (41) and anchoring it to the cap (2), wherein said frame (31) follows at least partially the perimeter of said structural lens (41).