What is BK7 material?

What is BK7 material?

BK7 is a high quality optical glass that is used whenever the additional benefits of fused silica are not required. Since BK7 performs well in all chemical tests, and no additional or special handling is required, costs of manufacturing are reduced.

What material has the lowest index of refraction that is used for spectacle lenses?

CR-39
CR-39 has the lowest index of refraction of all currently used spectacle lens materials, so lenses made of CR-39 are thicker than those made from other materials.

What is the refractive index of polycarbonate?

1.59
Polycarbonate lenses have a refractive index of 1.59. Polycarbonates have a great ability to resist impact and are even lighter that high-index plastic lens.

What is a BK7 prism?

The less expensive BK-7 prisms have squared-off, non-circular exit pupils. The design of the prisms can affect the quality of the exit pupil. The BK7 prism typically found in lower priced binoculars produces an exit pupil with shaded (blurred) edges, whereas the BAK4 prism has a perfectly round exit pupil.

Is BK7 fused silica?

It has excellent resistance to non-fluorinated acids, solvents and plasmas. Heraeus and Nikon both produce extremely high grade (pure) Fused Silica glasses that exhibit excellent ultraviolet and infrared performance. Bk7 is a barium borosilicate glass known for its high transmission and clean, clear appearance.

What is N BK7 glass?

N-BK7 is a very pure universal optical glass made by SCHOTT. It is one of the most standard glass types used to produce high-quality optics, mainly for the visible spectrum. The relatively hard borosilicate crown material consists of the purest raw ingredients.

What lens material is best?

polycarbonate
When eye safety is a concern, polycarbonate or Trivex lenses usually are the best choice for your eyeglasses, sunglasses and sports eyewear. These lenses are significantly more impact-resistant than other lenses and: Are noticeably lighter and thinner than regular plastic lenses.

Which is better CR-39 or polycarbonate?

In comparison to polycarbonate, CR-39 provides vastly superior optics, rating just one rung below the material with the highest ABBE value: crown glass. If you choose CR-39 lenses you commonly find that UV-protection comes at an added cost because, unlike polycarbonate, they aren’t inherently UV-protected.

Is Bak-4 better than bak7?

For binoculars, spotting scopes, and monoculars, BaK-4 is generally preferable to BK-7 or K9 as it has a higher refractive index and, when used in a well-designed overall optical system, provides higher levels of image quality than would a prism assembly of the same type made with BK-7 or K9 glass.

Which is better Porro or BAK4?

BAK-4 prisms are considered the best type of Porro prism as they are made of superior optical glass to produce clearer images. BK-7 prisms are also used, usually in lower priced binoculars. These are satisfactory, but inferior to the BAK-4 prisms.

Is BK7 a borosilicate glass?

Bk7 is a barium borosilicate glass known for its high transmission and clean, clear appearance. These characteristics make Borofloat more costly than float glass, but borosilicates retain shape and handle thermal shock better than other, less expensive glasses.

What is BK7 glass used for?

BK-7 OPTICAL GLASS. BK7 is a high quality optical glass that is used whenever the additional benefits of fused silica are not required. Since BK7 performs well in all chemical tests, and no additional or special handling is required, costs of manufacturing are reduced.

What are the advantages of BK7?

Since BK7 performs well in all chemical tests, and no additional or special handling is required, costs of manufacturing are reduced. It is a relatively hard material with extremely low bubble and inclusion content, while providing excellent transmittance through-out the visible and near infrared spectra and down to 350 nm in the ultraviolet.

What type of optical glass does Glass Dynamics use?

For all standard optical glass components, or when optical glass is generically requested for custom elements, Glass Dynamics uses normal high quality BK7 optical glass. OPTIMUM TRANSMISSION RANGE 350nm – 2.0µm

Which optical glasses have the best transmission in the NUV?

Crown glasses tend to have better transmission in the NUV than do flint glasses. Flint glasses, because of their high index, feature higher Fresnel reflection loss and thus should always be specified with an anti-reflection (AR) coating. Figure 1: Sample Optical Glass Transmittance Curves