polycarbonate

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polycarbonate

(pŏl″ē-kăr′bĭ-nāt, -nĭt) [″ + ″]
A transparent polymer used to manufacture eye protectors, shields, and other medical devices.
Medical Dictionary, © 2009 Farlex and Partners

Polycarbonate

A very strong type of plastic often used in safety glasses, sport glasses, and children's eyeglasses. Polycarbonate lenses have approximately 50 times the impact resistance of glass lenses.
Gale Encyclopedia of Medicine. Copyright 2008 The Gale Group, Inc. All rights reserved.

index of refraction

The ratio of the speed of light in a vacuum or in air, c, to the speed of light in a given medium, v. Symbol: n. Hence,
n = c/v
The speed of light in a given medium depends upon its wavelength. Consequently, the index of refraction varies accordingly, being greater for short wavelengths (blue) than for longer wavelengths (red). The index of refraction forms the basis of Snell's law, which quantitatively determines the deviation of light rays traversing a surface separating two media of different refractive indices. Syn. refractive index. Plural: indices. See dispersion; law of refraction; gradient-index lens; high index lens; speed of light; refractometer.
Table I3 Refractive indices of some transparent media at selected wavelengths
spectral lineGFDCA
OriginCalciumHydrogenSodiumHydrogenOxygen
wavelength (nm)430.8486.1589.3656.3759.4
aqueous or vitreous humour1.34401.34041.33601.33411.3317
crystalline lens1.43071.42591.42001.41751.4144
spectacle crown1.53481.52931.52301.52041.5163
dense flint1.63971.62901.61701.61221.6062

Table I4 Index of refraction n of various media for sodium light (λ = 589.3)
air1.00
water (at 20ºC)1.333
spectacle crown glass1.523
flint glass (dense)1.62
flint glass (extra dense)1.65-1.70
titanium oxide glass1.701
calcite crystal
ordinary ray1.658
extraordinary ray1.486
quartz crystal
ordinary ray1.544
extraordinary ray1.553
diamond2.42
Canada balsam1.53-1.54
CR-391.498
polycarbonate1.586
silicone rubber1.44
CAB1.47
PMMA1.49
HEMA1.43
hydrogel polymer
20% water content1.46-1.48
75% water content1.37-1.38
eye
tears1.336
cornea1.376
aqueous humour1.336
crystalline lens (average effect)1.42
vitreous humour1.336

plastic 

Various organic or synthetic materials (e.g. CR-39, HEMA, polymethyl methacrylate, polycarbonate, etc.) that can be transformed into solid shapes to make spectacle frames, contact lenses, ophthalmic lenses, etc. and can be made to have good optical surfaces, high light transmission and refractive indices and dispersions similar to that of crown or flint glass. See acetone; index of refraction; plastic spectacle frame.
Millodot: Dictionary of Optometry and Visual Science, 7th edition. © 2009 Butterworth-Heinemann
References in periodicals archive ?
"We want to bring Makrolon polycarbonate to more medical applications in China based on the proven successful cases in Europe and North America."
Bayer MaterialScience develops, produces and sells Makrolon polycarbonate sheets, Axpet and Vivak polyester sheets, as well as Bayloy high-quality plastic sheets.
The Bayer researchers set to work on Makrolon polycarbonate and succeeded in modifying it for the special requirements of manufacturing processes in the music industry.
Working with ACI Medical in San Marcos, CA, a medical device design and molding company, Terumo selected Makrolon Rx2530 polycarbonate resin, by Bayer Material Science, Pittsburgh, PA, as the material to be used for the EC junction.
The Sheffield, Mass., firm produces Makrolon, a polycarbonate sheet that combines toughness and flexibility, according to D.J.
Also available are posts with a Test Station Terminal Enclosure constructed of makrolon polycarbonate, with stainless steel hardware and 11 accessible terminals.
The lid is molded in Bayer's Makrolon polycarbonate.
Sheffield's new generation of laminates, featuring Makrolon AR hard-coat technology, assures long-lasting surface clarity and resistance to yellowing.
The monitor bezel, with an integrated Makrolon window, has a 14.57" X 10.83" viewing area designed for 19" diagonal screens.