Plastic Lens Composition for High HEV Blocking Stability
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Solution Overview
Problem
Existing plastic lenses have limitations in improving the High Energy Violet (HEV) cut rate, which is the percentage of cutting light with wavelengths between 400 nm and 420 nm, essential for eye protection.
Innovation Solution
A plastic lens using a polymerizable compound comprising xylene diisocyanate and polythiol, combined with a benzotriazole compound as an ultraviolet absorber, is developed to enhance the HEV cut rate, with specific proportions and thickness to prevent absorber precipitation and maintain lens quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional ultraviolet absorbers are used in plastic lenses, then ultraviolet rays below 400 nm are cut, but the HEV cut rate cannot be improved beyond a certain limit
Solution Approach 1:
The patent changes the chemical parameters of the ultraviolet absorber by specifying a benzotriazole compound with a particular molecular structure (Formula 1) where R represents specific alkyl groups. This structural parameter change enables the absorber to effectively cut HEV light while maintaining stability. The proportion parameter is also optimized to less than 0.62 parts by weight relative to 100 parts by weight of polymerizable compound, achieving high HEV cut rate without compromising lens performance
Solution Approach 2:
The patent creates a composite system by combining the benzotriazole compound ultraviolet absorber with specific polymerizable compounds (xylene diisocyanate and polythiol). This composite material approach allows the lens to achieve both high HEV cut rate and maintained optical properties, resolving the contradiction between harmful factor reduction and performance stability
2Object-affected harmful factors
If the proportion of ultraviolet absorber is increased to improve HEV cut rate, then more HEV light is blocked, but the absorber may precipitate and deteriorate lens quality
Solution Approach 1:
The patent optimizes the concentration parameter of the ultraviolet absorber to a specific range (less than 0.62 parts by weight per 100 parts by weight of polymerizable compound). This parameter optimization ensures sufficient HEV cut rate while preventing absorber precipitation and maintaining compositional stability, thus resolving the contradiction between blocking effectiveness and dissolution stability
Solution Approach 2:
The patent uses the polymerizable compound (specifically the combination of xylene diisocyanate and polythiol) as an intermediary medium that maintains the dissolution of the benzotriazole compound. This intermediary system allows the absorber to remain dissolved at effective concentrations without precipitating, resolving the stability contradiction
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 plastic lens achieves an HEV cut rate of not less than 94%, providing excellent eye protection by effectively blocking harmful high-energy visible light while maintaining lens appearance and transparency.
Implementation Method 1
a benzotriazole compound as an ultraviolet absorber... effectively blocking harmful high-energy visible light... HEV cut rate of not less than 94%
Data Source
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AI summary
Provided are a plastic lens and spectacles having a high HEV cut rate represented as 100-(average transmittance in a wavelength range of not less than 400 nm and not greater than 420 nm). [Solution] A plastic lens according to the present invention includes a plastic lens base material obtained as a result of curing of a polymerizable compound having mixed therein a benzotriazole compound represented by general formula (1) below. Spectacles according to the present invention is produced by using the above-described plastic lens as a plastic spectacle lens.