Variable-Transmission Eyewear Lens With Rear UV Screening Layer

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Solution Overview

Problem

Conventional eyeglass lenses do not provide effective protection across all lighting conditions and UV and visible frequencies, and lack aesthetic versatility.

Innovation Solution

A multilayer lens design with a photochromatic layer positioned in front of a UV filter layer, allowing for adjustable tint and enhanced protection, featuring a photochromatic layer with transmittance between 10-60% and 80-95% in activated and deactivated states, respectively, and a UV filter with less than 0.5% transmittance in the 280-400 nm range.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If traditional eyeglasses or sunglasses are used, then vision correction or UV protection is provided, but they cannot adapt to changing light conditions and require multiple pairs for different environments

Engineering Contradiction:
Improveadaptability to light conditionsVSAvoidnumber of lens layers
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent combines multiple lens functionalities into a single variable transmission lens. The first and second lenses are merged into one integrated lens structure that provides both the refractive power for vision correction and the variable transmission capability for adapting to different light conditions, eliminating the need for separate prescription glasses and sunglasses

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The variable transmission lens serves multiple functions simultaneously: it provides vision correction through its refractive properties, adapts transmission levels in response to ambient light conditions, and protects against excessive light exposure. This multi-functionality allows a single lens to replace multiple specialized lenses

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

2Adaptability or versatility

If photochromic material is used to enable lenses to darken in UV light, then adaptability to light conditions is improved, but the lenses require prolonged exposure to darken and cannot be used in vehicles with windshields that block UV

Engineering Contradiction:
Improveresponse time to light conditionsVSAvoiddelayed response and UV blocking interference
Core Design Contradiction:
Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The patent changes the operational parameter of the light-sensitive material from UV-responsive to visible light-responsive. By selecting a material that responds to visible wavelengths rather than UV wavelengths, the lens can darken rapidly in response to ambient light conditions and function effectively inside vehicles where windshields block UV radiation

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent substitutes the photochromic mechanism (which requires UV exposure and slow chemical reaction) with a different light-sensitive mechanism that responds to visible light. This substitution enables faster response times and eliminates dependence on UV penetration, allowing the lens to function in vehicular environments

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

3Ease of operation

If electrochromic material is used to enable electronic control of transmission, then precise control is achieved, but power consumption increases and liquid crystal materials require significant power to maintain state

Engineering Contradiction:
Improvecontrol precisionVSAvoidpower consumption
Core Design Contradiction:
Ease of operationVSUse of energy by moving object

Solution Approach 1:

The patent employs a materials system that is self-regulating and does not require continuous external power. The light-sensitive material automatically adjusts the lens transmission based on ambient light conditions without needing electronic control signals or power input to maintain its state, eliminating the high power consumption associated with electrochromic and liquid crystal materials

Inventive Principle:
Principle #25Self-service

4Adaptability or versatility

If variable transmission lenses are made thicker to incorporate multiple functionalities, then adaptability and protection are improved, but aesthetics and comfort are compromised

Engineering Contradiction:
Improvefunctional integrationVSAvoidlens thickness
Core Design Contradiction:
Adaptability or versatilityVSShape

Solution Approach 1:

The patent merges multiple functional layers into a single integrated lens structure with uniform thickness. By combining the vision correction functionality and variable transmission functionality into one lens rather than layering separate lenses, the design achieves full functionality without increasing overall lens thickness, thereby maintaining aesthetic appearance and佩戴 comfort

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

Ensures consistent protection across varying lighting conditions while offering a visually appealing aesthetic change based on the photochromatic layer's activation state.

Implementation Method 1

The variable transmission lens may be made with a base lens and a light-sensitive material overlaid on the base lens. The light-sensitive material may be a photochromic material, an electrochromic material, a liquid crystal material, or other materials known to provide variable light transmission properties in response to ambient light conditions.

Methodology Applied
Scientific EffectPhotochromism: Photochromism

Data Source

PatentEP3698207B1Eyewear with variable transmission lens
Publication Date: 2026.04.29 LUXOTTICA SRL
  • EP3698207B1 patent drawingFigure 1
  • EP3698207B1 patent drawingFigure 2~3
  • EP3698207B1 patent drawingFigure 4A~5B

AI summary

A lens for sunglasses includes a convex front surface, functionally directed toward an item to be viewed, and a concave rear surface, functionally directed toward the eye of a person who is wearing the eyeglasses. The lens further includes a photochromatic layer, proximate to the front surface, and a screening layer defining a UV filter, proximate to the rear surface and arranged between the rear surface and the photochromatic layer. The photochromatic layer is in the range of wavelengths comprised between 380 nm and 780 nm and has a transmittance comprised between 10% and 60%, in an activated state thereof, and a wavelength comprised between 80% and 95%, in a deactivated state thereof. The screening layer has a transmittance lower than 0.5% in the range of wavelengths comprised between 280 nm and 400 nm.