Transparent Optical Article With Blue-Light Cutoff and Color Balance
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Solution Overview
Problem
Existing optical articles fail to provide sufficient protection against harmful blue light and UV light while maintaining good aesthetics, transparency, and color perception, often sacrificing either cost or appearance to meet blue light cut-off standards.
Innovation Solution
A transparent optical article comprising a thermoplastic substrate with a non-fluorescent UV absorber and a fluorescing dye that blocks blue light and UV light, featuring a spectral transmission curve with a cut-off wavelength of 400 nm and an inflection point with a slope greater than 6%/nm, along with a fluorescence level below 2% from 415 nm to 445 nm, and a color balancing agent to maintain aesthetics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a yellow dye is incorporated into the optical element to block blue light from 400 nm to 460 nm, then blue light protection is improved, but the lens exhibits excessive yellowness and poor aesthetics
Solution Approach 1:
The patent applies color balancing agents (cyan and green dyes) to counteract the yellow coloration caused by the blue light blocking dye. This creates a multi-dye system where the yellow dye blocks blue light while cyan and green dyes balance the color to maintain visual transparency and aesthetic appearance, resolving the contradiction between protection and appearance.
Solution Approach 2:
The patent uses a composite approach by combining multiple dyes (yellow for blue light blocking, cyan and green for color balancing) within the optical element. This composite dye system achieves both blue light protection and maintained aesthetics, overcoming the limitation of using a single yellow dye that provides protection but degrades appearance.
2Object-affected harmful factors
If the cut-off wavelength is increased to 400 nm to meet CNIS standards, then blue light protection is improved, but the slope at inflection point decreases and aesthetics are compromised
Solution Approach 1:
The patent optimizes the concentration ratios of multiple dyes to achieve the desired spectral characteristics. By carefully adjusting the parameters of dye concentrations (yellow dye at 0.01-0.1 wt%, cyan and green dyes at optimized ratios), the patent achieves both the 400 nm cut-off wavelength requirement and maintains a sufficient slope at the inflection point while preserving aesthetics.
3Illumination intensity
If optical brighteners are incorporated to balance color, then aesthetics are improved, but UV absorbers interfere with the fluorescence emission and blue light protection is reduced
Solution Approach 1:
The patent extracts or eliminates the optical brightener component from the system. Instead of using optical brighteners that would interfere with UV absorption and fluorescence, the patent achieves color balancing solely through cyan and green dyes, thereby maintaining both aesthetic appearance and effective blue light protection without the interference problem.
4Illumination intensity
If multiple dyes are used to maintain color neutrality, then aesthetics are improved, but the manufacturing complexity and cost increase
Solution Approach 1:
The patent applies different dyes with specific functions at different spectral regions: yellow dye for blue light blocking (400-460 nm), cyan and green dyes for color balancing in the visible range. This localized functional assignment optimizes each dye's contribution while maintaining overall color neutrality and simplifying the formulation approach.
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 effectively blocks harmful blue light and UV light, maintaining high transparency and acceptable color perception, meeting CNIS blue light cut-off standards while being cost-effective and easy to implement industrially.
Implementation Method 1
at least one UV absorber
Implementation Method 2
at least one fluorescing dye at least partially inhibiting transmission of light having a wavelength ranging from 400 nm to 500 nm
Implementation Method 3
the transparent optical article has an average fluorescence as determined according to the standard ASTM E1247 lower than or equal to 2% in the range from 415 nm to 445 nm
Data Source
AI summary
The invention relates to a transparent optical article comprising a thermoplastic substrate, at least one UV absorber, and at least one fluorescing dye at least partially inhibiting transmission of light having a wavelength ranging from 400 to 500 nm, wherein the spectral transmission curve of said transparent optical article has a light cut-off wavelength higher than or equal to 400 nm and an inflection point at a wavelength ranging from 400 to 450 nm, and the slope at said inflection point is higher than or equal to 6%/nm.