Optical glass
Description
A fine grade of Glass used in microsopes, telescopes, binoculars, cameras, and other items requiring visual acuity. Primary patents for making optical glass were made in 1798 by P.L. Guinand, a Swiss inventor. Commercial processes for making consistent quality glass were developed in the mid 19th century when the Chance brothers in England introduced the melt-stirring process. Concurrent work in Germany by the Zeiss Company, Ernst Abbe, and Otto Schott established Jena Glass Works as a major supplier of optical glass. Optical glass is clear, flawless, and has a very controlled refractive index. Flint glass produces a higher refractive index and dispersive power while Soda-lime glass, or Crown glass, produces a lower refractive index and lower dispersive power. Optical glasses are cooled slowly and sometimes annealed for months to minimize distortions. Optical glass is used for the manufacture of optical systems using optical lenses, prisms or mirrors such as microscopes, telescopes, cameras, binoculars and spectroscopic instruments.
Synonyms and Related Terms
crystal; lens; eyeglass; magnifying glass; flint glass
Physical and Chemical Properties
- Insoluble in all solvents except hydrofluoric acid.
- Density = 3.86 g/ml
- Refractive index = 1.65
- Glass transition temperature - ~540 C
- Warm to touch compared to minerals
Resources and Citations
- Wikipedia: Optical glass (Access Oct. 2023)
- Encyclopedia Britannica, http://www.britannica.com Comment: "industrial glass" [Accessed May 5, 2004].
- Edward Reich, Carlton J. Siegler, Consumer Goods: How to Know and Use Them, American Book Company, New York City, 1937
- Random House, Webster's Encyclopedic Unabridged Dictionary of the English Language, Grammercy Book, New York, 1997
- The American Heritage Dictionary or Encarta, via Microsoft Bookshelf 98, Microsoft Corp., 1998