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The resulting glass code is the value of n d − 1 rounded to three digits, followed by V d rounded to three digits, with all decimal points ignored. For example, BK7 has n d = 1.5168 and V d = 64.17, giving a six-digit glass code of 517642. [1] Consequently, a linear approximation for the refractive index dispersion close that wavelength is ...
Glasses, also known as eyeglasses or spectacles, are vision eyewear with clear or tinted lenses mounted in a frame that holds them in front of a person's eyes, typically utilizing a bridge over the nose and hinged arms, known as temples or temple pieces, that rest over the ears for support.
The first commercial use of CR-39 monomer (ADC) was to help create glass-reinforced plastic fuel tanks for the B-17 bomber aircraft in World War II, reducing the weight and increasing the range of the bomber. After the war, the Armorlite Lens Company in California is credited with manufacturing the first CR-39 eyeglass lenses in 1947.
To combat fake solar eclipse glasses, the American Paper Optics team created the Core Four elements of eclipse glasses to look out for to ensure your safety during the solar event.
Zenni Optical mail order. Zenni Optical was founded in 2003 by Tibor Laczay and Julia Zhen. [1] [2] Before being renamed to Zenni Optical when it began offering $7 and $8 glasses, the company was named 19dollareyeglasses.com. [3] [4] [5] Around 2014, co-founder Zhen acquired the building occupied by the Marin Independent Journal to house Zenni. [6]
Upon the release of the printing press and the mass adoption of literature, larger sectors of the population began to buy into eyewear to assist with reading. Eyewear frames around this time were mainly made of animal bones, horns and fabric; the implementation of wire frames in the 16th century further allowed glasses to be mass-produced.
Inexpensive lenses may have deviations of form as large as several wavelengths (λ, 2λ, etc.). More typical industrial lenses would have deviations no larger than a quarter wavelength (λ/4). Precision lenses for use in applications such as lasers, interferometers, and holography have surfaces with a tenth of a wavelength (λ/10) tolerance or ...
The AN6531 Comfort Cable aviator sunglasses frame kept being issued by the U.S. military as No. MIL-G-6250 glasses after World War II with different lenses as Type F-2 (arctic) and Type G-2 aviator sunglasses but fitted with darker lenses until their substitute, the Type HGU-4/P aviator sunglasses, became available in the late 1950s.