What is Optical Glass?
The use of cold glass techniques is not limited to optical glass. However, optical glass is the perfect material to to take full advantage of advanced cold processes. Optical quality glass refers to the bubble free, striae* free, precision annealed** glass that is used in the optical industry. Each type of glass is formulated to have specific properties that allow it to meet criteria for its use. An example of a common use for optical glass would be professional camera lenses. Each lens may have multiple individual component lenses made of many different glasses shaped to varying curvatures and coated with thin vacuum films to create the perfect optics for a particular type of photography. Optical glass also is produced in color. The colored filters that can be purchased to place on a cameral lens are the most common use for these materials. More exotic color filters are also created, mostly for high technology and military uses. These glasses are usually made by the optical glass manu
Optical glass is a specialty glass product which is designed for use in optical devices such as telescopes, binoculars, eyeglasses, and so forth. This glass is formulated very precisely so that its properties are known, and it must be handled with care to ensure that it is free of impurities and produced in the right conditions. High quality optical glass can be quite expensive, as it requires a great deal of work to produce, and some of that work must be done by hand, especially in the case of custom pieces. People have been exploring optical glass since at least the 1600s, when glass workers began refining existing techniques to create glass which could be used to create lenses. These early lenses were used in simple microscopes and corrective vision devices. While the quality of this optical glass was not very good when compared to modern products, it did establish the fact that glass had a range of potential uses, and that refinement of glass making techniques could result in even
Optical glass, as with all glasses, is basically made of sand plus a few other bits and bobs, melted and then left to cool. Of course the devil is in the detail. There are well over 1000 optical glasses from 5 or 6 main manufacturers [Schott, Ohara, Hoya etc]. Many of these are essentially just different versions of the same glass, so there are probably about 1-200 actual glasses. Why so many – surely glass is glass? Well no. Those ‘bits and bobs’ make all the difference. Most people, for example know of Waterford crystal – this is a glass with a very high percentage of lead. That lead gives the glass its weight, but also a high index and dispersion which makes it so attractive when made into its final shape. Other additives impact on the materials in various ways. Each glass has a name, or more precisely, an identifier. One of the most common is known as BK7. Others include SF6 or LaKN6 – hardly inspiring – but crucial to the lens designer.
The French Reflection offers the option of optically ground mirror lenses. Optical glass is an optician’s lens that have been silvered and are hand ground to further enhance its magnification quality. Optical lens in either 3x or 7x OPT. glass provides distortion-free reflection of unparalleled clarity. Optical lens inset into optical glass mirror face for clearer, most evenly distributed illumination, Beveled edge for insert prevents refraction and distortion. For more information on magnifications and optical glass: Go to “The French Reflection Difference” and then click on the various magnifications to see the difference high quality wall mirrors can offer you.
The French Reflection offers the option of optically ground mirror lenses. Optical glass is an optician’s lens that have been silvered and are hand ground to further enhance its magnification quality. Optical lens in either 3x or 7x OPT. glass provides distortion-free reflection of unparalleled clarity. Optical lens inset into optical glass mirror face for clearer, most evenly distributed illumination, Beveled edge for insert prevents refraction and distortion. Go to “The French Reflection Difference” and then click on the various magnifications to see the difference a high quality wall mirror can offer you.
