In the previous article, we discussed “What is lens base bending?”. In this article, let’s talk about “What are NXT Lenses?”.
What are NXT Lenses?
NXT lenses are made of Trivex materials. Trivex (Chinese name: Ethyl Carbamate Polymer) was invented by PPG in 2001.
Characteristics of NXT lenses
Impact resistance is the main feature of the NXT lens. As a visual armor material originally used in the military field, Trivex has effective impact protection to the eye when it is most demanded. It is 10 times stronger than PC lenses in impact resistance and will last for life under normal use. It is the only explosion-proof safety lens on the market that can withstand external forces and turns.
Patented "color injection technology" :
Color representation is another important feature of NXT lenses. The biggest defect of the regular lens in dyeing is color aberration. The same color of the lens with different luminosity will produce different effects. The higher the refractive index, the serious the error. NXT lenses are a breakthrough in this respect. The patented "color injection technology" that infuses the color into the raw material gives the lens a natural color, ensuring that color aberrations are minimized and that they do not fade or change color over time or over long periods of use like other materials.
Abbe number and internal stress:
The Abbe number of NXT lenses made of Trivex is 43~45, which is close to CR39(58) and higher than PC lenses (29~32) and high folding lenses (32~41). At the same time, because the NXT lens is produced by the casting process, there is no stress in the finished lens, which further reduces the rainbow phenomenon, providing a guarantee for the clear visual effect and reducing eye fatigue.
The specific gravity of NXT lens is 1.11g/cm3, 16% lighter than CR39 (1.32g/cm3) and 10% lighter than PC tablet (1.22g/cm3). The Trivex 1.53NXT medium-fold lens is so light that it can float.
Limitations of NXT lenses
NXT lenses made from Trivex can't be cut by means of traditional edge cutting ways, requiring certain edge grinders, which has caused some problems for retail stores. Therefore, now NXT lenses are more used in some glasses, like sunglasses, protective goggles, and so on.
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