Eyeglass UV Protection Index Calculation
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Solution Overview
Problem
Existing methods for rating eyeglasses for UV protection do not adequately quantify the total UV radiation that enters the eye, failing to account for various exposure conditions, particularly when radiation is reflected from the eyeglass back face.
Innovation Solution
A method that calculates an index value by integrating spectral transmission and reflection values weighted for hazard and intensity over a UV wavelength range, combining these values using an addition formula to account for both transmission and reflection-based UV exposure, with optional adjustments for geometric and physiological parameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If only transmission value is used for rating UV protection, then the rating method is simple, but it fails to account for reflected UV radiation from the back face of the eyeglass
Solution Approach 1:
The patent combines multiple measurement components (transmission measurement and back-face reflection measurement) into a unified rating system. The total UV protection rating is calculated by integrating both the transmission value through the lens and the reflection value from the back face, providing a comprehensive assessment that accounts for all UV exposure pathways.
2Measurement precision
If transmission and reflection values are both measured and combined, then the UV protection rating becomes more accurate, but the measurement and calculation process becomes more complex
Solution Approach 1:
The patent divides the UV protection assessment into distinct measurable components: transmission measurement through the lens and reflection measurement from the back face. Each component is measured separately using specific optical pathways and then combined through a standardized calculation formula, making the complex process systematic and manageable.
Solution Approach 2:
The patent introduces an intermediary calculation framework that processes the raw transmission and reflection measurements into a unified protection rating. This intermediary step uses a standardized formula that combines the two measurement values with appropriate weighting, bridging the gap between separate measurements and the final comprehensive rating.
3Measurement precision
If the rating method accounts for multiple exposure conditions including reflection, then it quantifies total UV exposure more completely, but the ease of understanding the rating for customers decreases
Solution Approach 1:
The patent transforms complex multi-parameter measurements (transmission, reflection, angular dependencies) into a single simplified rating parameter that maintains scientific rigor while being easy to communicate. The final protection rating is expressed as a unified value that encapsulates all UV exposure pathways, allowing customers to compare different eyeglasses using a single number.
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
This method provides a comprehensive and easily understandable rating of UV protection efficiency, effectively quantifying the reduction in UV exposure for the eye, allowing for better selection of eyeglasses based on their UV protection capabilities.
Implementation Method 1
a first transmission value for each eyeglass in the UV wavelength range from 280 nm (nanometer) to 400 nm
Implementation Method 2
a second transmission value for each eyeglass in the blue wavelength range from 400 nm to 500 nm, and a further value for quantifying the amount of incident light that reaches the eye from around the frame
Data Source
AI summary
An index value is calculated for rating an eyeglass with respect to protection against UV hazard. The index value is based on an integrated UV transmission value through the eyeglass and an integrated UV reflection value related to a back face of the eyeglass. Thus, the index value takes into account actual wearing conditions where UV eye exposure is due either to transmission through the eyeglass or reflection on the eyeglass back face. Respective index values obtained for a set of eyeglasses allow easy sorting of the eyeglasses with respect to UV protection efficiency.