推 KITAKITA:我印象中石英可穿UV，其他多少會擋....有人有光譜嗎？ 09/11 23:52
As to 精華區 7→1→5→18
http://en.wikipedia.org/wiki/Ultraviolet
看到Glass似忽可以「擋」紫外線，所以就翻了一下網路上的資料，
然後發現
Ordinary glass is partially transparent to UVA but is opaque to shorter
wavelengths while Silica or quartz glass, depending on quality, can be
transparent even to vacuum UV wavelengths. Ordinary window glass passes about
90% of the light above 350 nm, but blocks over 90% of the light below 300 nm
所以，其實擋不擋還是要看材質。
UVA, UVB, UVC etc來說，照文章意思好像是UVA擋一部份，UVB, UVC擋掉（視材質）。
但因為UVA最弱（以hν=能量而言）所以是有擋一些的作用。
Eye
High intensities of UVB light are hazardous to the eyes, and exposure can
cause welder's flash (photokeratitis or arc eye) and may lead to cataracts,
pterygium [9] [10], and pinguecula formation.
Protective eyewear is beneficial to those who are working with or those who
might be exposed to ultraviolet radiation, particularly short wave UV. Given
that light may reach the eye from the sides, full coverage eye protection is
usually warranted if there is an increased risk of exposure, as in high
altitude mountaineering. Mountaineers are exposed to higher than ordinary
levels of UV radiation, both because there is less atmospheric filtering and
because of reflection from snow and ice.
Ordinary, untreated eyeglasses give some protection. Most plastic lenses give
more protection than glass lenses, because, as noted above, glass is
transparent to UVA and the common acrylic plastic used for lenses is less so.
Some plastic lens materials, such as polycarbonate, inherently block most UV.
There are protective treatments available for eyeglass lenses that need it
which will give better protection. But even a treatment that completely
blocks UV will not protect the eye from light that arrives around the lens.
不過即使可以擋，對周圍的皮膚還是有傷害的。而且還是用塑膠的護目鏡為宜。
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※ 編輯: Ren 來自: 76.201.144.184 (09/11 23:28)