18,519
edits
Sunglasses: Difference between revisions
From ScoutWiki, For Everyone, Everywhere involved with Scouting and Guiding...
m
Robot: Automated text replacement (-\[\[(Glass)\]\] +\1)
m (Robot: Automated text replacement (-\[\[(Rubber)\]\] +\1)) |
m (Robot: Automated text replacement (-\[\[(Glass)\]\] +\1)) |
||
| Line 48: | Line 48: | ||
Corrective lenses can be darkened to serve the same purpose, or secondary clip-on dark lenses can be placed in front of the regular lenses. Some lenses graually darken with bright light and lighten in darkness. These are known as [[photochromic lens]]es. | Corrective lenses can be darkened to serve the same purpose, or secondary clip-on dark lenses can be placed in front of the regular lenses. Some lenses graually darken with bright light and lighten in darkness. These are known as [[photochromic lens]]es. | ||
Sunglass lenses are made from either | Sunglass lenses are made from either glass or plastic. Plastic lenses are typically made from [[Polymethyl methacrylate|acrylic]], [[polycarbonate]], or [[CR-39]]. Glass lenses have the best optical clarity and scratch resistance, but are heavier than plastic lenses. They can also shatter or break on impact. Plastic lenses are lighter than glass lenses, but are more prone to scratching. They do however, offer more resistance to shattering than glass. Polycarbonate lenses are the lightest, and are also almost shatterproof, making them good for impact protection. <!--They are probably more expensive, though. Right?--> CR-39 lenses are the most common plastic lenses, due to their low weight, high scratch resistanc, low transparency for ultraviolet and infrared radiation, and other advantageous properties. | ||
For sunglasses that also include vision correction, see also [[corrective lens]]. | For sunglasses that also include vision correction, see also [[corrective lens]]. | ||
