Spectacle Lens Selective Blue Light Filtering for LED Headlight Glare
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Solution Overview
Problem
Spectacle lenses for car drivers fail to effectively reduce glare from modern LED and Xenon HID headlights while maintaining visibility of objects, as existing blue light filtering technologies either reduce object visibility or cause yellowish tint under daylight conditions.
Innovation Solution
A spectacle lens with selective light wavelength filter properties, including a spectral transmittance of 80-95% between 428 nm and 452 nm and 95-100% between 500 nm and 700 nm, using a substrate made from mineral or organic materials, with blue light attenuating properties achieved through dyes, pigments, or multilayer dielectric coatings, to minimize glare while preserving object visibility and color perception.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If blue light filtering coatings or dyes are applied to block wavelengths between 400-500 nm, then glare from LED and Xenon HID headlights is reduced, but object visibility and color perception deteriorate
Solution Approach 1:
The patent applies different optical properties to different wavelength ranges: the coating selectively blocks blue light (400-500 nm) while transmitting other visible wavelengths (500-700 nm) with high transmission (95-100%). This local differentiation of optical properties allows glare reduction in the blue spectrum while preserving overall visibility and color perception in the green-red spectrum.
Solution Approach 2:
The patent specifies precise transmittance parameters: 80-95% transmittance in the blue light range (428-452 nm) and 95-100% transmittance in the green-red range (500-700 nm). By controlling these quantitative parameters, the coating achieves optimal balance between glare reduction and visibility preservation.
2Object-affected harmful factors
If strong blue light blocking is implemented, then glare reduction improves, but yellowish tint appears under daylight conditions
Solution Approach 1:
The coating selectively targets only the blue light spectrum (400-500 nm) for attenuation while leaving the green (500-560 nm) and red (600-700 nm) portions of the spectrum unaffected. This selective local action prevents the overall yellowish tint that would result from blocking broader wavelength ranges, as the green and red components maintain natural color balance.
Solution Approach 2:
The patent defines specific transmittance ranges: 80-95% for blue light (428-452 nm) and 95-100% for green-red light (500-700 nm). These controlled parameter changes ensure sufficient glare reduction while maintaining color neutrality, preventing the yellowish cast that occurs with stronger or broader spectrum blocking.
3Object-affected harmful factors
If spectral transmittance in blue light range is reduced to 80-95%, then glare from LED headlights is minimized, but overall light transmission is compromised
Solution Approach 1:
The coating concentrates its optical action locally in the blue light spectrum (400-500 nm) where LED and Xenon HID headlights emit most of their glare-causing energy. By limiting the attenuation to this specific local wavelength range while maintaining high transmission (95-100%) in the green-red spectrum, the coating minimizes overall impact on light transmission efficiency.
Solution Approach 2:
The patent optimizes the transmittance parameters to achieve 80-95% in the blue range (sufficient for LED glare reduction) and 95-100% in the green-red range (maximizing overall transmission). This parameter optimization ensures adequate glare protection while minimizing compromise to overall light transmission efficiency.
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 significantly reduces glare from LED and Xenon HID headlights while ensuring objects remain visible and maintaining true color perception, with minimal darkening and residual reflection, enhancing driving safety and comfort.
Implementation Method 1
a first multilayer dielectric coating disposed on the front surface of the substrate. The front face of the spectacle lens exhibits a maximum reflectance in the visible spectrum at a wavelength of from 430 nm to 470 nm
Implementation Method 2
the front face of the spectacle lens exhibits a reflectance of from 2% to 18% reflectance at 400 nm, of from 5% to 30% reflectance at 450 nm, and of from 3% to 20% reflectance at 500 nm
Implementation Method 3
The substrate including at least one of a dye, a pigment and a tint absorbing light of all wavelengths in the wavelength range between 428 nm and 452 nm, in particular between 432 nm and 448 nm
Data Source
AI summary
A spectacle lens having a front surface intended to be fitted away from the eye. The spectacle lens includes a substrate made from mineral glass or an organic material. The spectacle lens has selective light wavelength filter properties. The selective light wavelength filter properties include a spectral transmittance between 80% and 95% for all wavelengths in a wavelength range between 428 nm and 452 nm for a light ray entering the spectacle lens on the front surface at an angle of incidence of 0°, a spectral transmittance between 95% and 100% for all wavelengths in a wavelength range between 500 nm and 700 nm for a light ray entering the spectacle lens on the front surface with an angle of incidence of 0° and a yellowness index of no more than 10 for a standard illuminant D65 and a standard observer function of 2° (D65/2°).