Optical Filter Sunglasses Local Transmission Maxima
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing optical filters for sunglasses with low transmittance in the 400-650 nm range effectively filter out harmful UV light but limit color perception and cause fatigue due to chromatic adaptation, while sports glasses with higher transmittance cause color distortions and fatigue from high fluctuation ranges.
Innovation Solution
An optical filter design with local transmission maxima and minima in specific wavelength ranges, a convex transmittance curve between 440-470 nm and 570-590 nm, and a saddle point between 600-620 nm, along with a further local minimum at 625-655 nm, to enhance color perception and reduce chromatic adaptation, using a plastic matrix with specific pigment concentrations for production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the transmittance is reduced to less than 20% in the 400-650 nm range to filter harmful UV light, then UV protection is improved, but color perception and color saturation are limited
Solution Approach 1:
The patent applies local quality by creating specific transmission maxima in certain wavelength ranges (blue: 440-470 nm, yellow: 570-590 nm, orange/red: 600-620 nm) while maintaining low overall transmittance. This selective transmission of specific color components preserves color perception and saturation even when total light transmission is limited to less than 20%.
Solution Approach 2:
The patent changes the transmittance parameter profile across different wavelength ranges by introducing specific transmission maxima and minima. The convex overall profile with controlled fluctuation range (less than 8%) optimizes the balance between UV protection and color perception by carefully adjusting transmittance parameters in different spectral regions.
2Loss of information
If the transmittance is increased to over 30% or 60% in the 400-650 nm range to improve color perception, then color saturation is improved, but the filter becomes unsuitable for sunglasses requiring lower transmittance
Solution Approach 1:
The patent resolves this contradiction by applying local quality - increasing transmittance only in specific wavelength ranges (blue, yellow, orange/red) while maintaining low overall transmittance. The transmission maxima in these specific bands provide sufficient color saturation without exceeding the 20% overall transmittance limit required for sunglasses.
Solution Approach 2:
The patent uses parameter changes by defining a convex overall transmittance profile with controlled fluctuation range. This mathematical constraint ensures that while local transmission maxima provide color saturation, the overall transmittance remains below 20% across the 400-650 nm range, satisfying sunglasses requirements.
3Measurement precision
If the transmittance curve has high fluctuation ranges and high local rates of change to amplify certain wavelengths, then visual acuity is improved, but color distortions increase leading to wearer fatigue
Solution Approach 1:
The patent applies parameter changes by introducing a convex overall transmittance profile with a controlled fluctuation range of less than 8%. This constraint on the rate of change prevents excessive local variations that cause color distortions, while still allowing transmission maxima to provide sufficient visual acuity. The balanced parameter profile reduces chromatic adaptation requirements and wearer fatigue.
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 design achieves improved color perception and reduced fatigue by maintaining low transmittance while increasing contrast and reducing color distortions, allowing for longer wear without eye strain.
Implementation Method 1
Optical filters for sunglasses are known from the prior art. These have a transmittance of less than 20% for light wavelengths up to 650 nm, particularly for reducing UV light that is harmful to the human eye
Implementation Method 2
the optical filters can be manufactured from a plastic matrix in which between 400 and 700 ppm of a UV filter pigment, between 33 and 98 ppm of a blue pigment, between 75 and 96 ppm of a yellow pigment, between 124 and 174 ppm of a red pigment, and between 37 and 115 ppm of a green pigment are dispersed
Data Source
AI summary
The invention relates to an optical filter for sunglasses with a transmittance of less than 20% for light wavelengths from 400 nm to 650 nm, the transmission spectrum (1, 2, 3) having a local transmission maximum (5, 6, 7) or (9, 10, 11) in the light wavelength range between 440 nm and 470 nm (4) and between 570 nm and 590 nm (8) respectively, and having a local transmission maximum in the light wavelength range between 600 nm and 620 nm (12). The transmittance has a substantially convex overall profile (16), with a variation of less than 8%, below the connection line of the local transmission maximum between 440 nm and 470 nm and the local transmission maximum (9, 10, 11) between 570 nm and 590 nm.