Optical Lens

Optical lens is the lens made of optical glass. The definition of optical glass is the glass with uniform optical properties and specific requirements for optical properties such as refractive index, dispersion, transmittance, spectral transmittance and light absorption. Glass that can change the propagation direction of light and the relative spectral distribution of ultraviolet, visible or infrared light. In a narrow sense, optical glass refers to colorless optical glass; In a broad sense, optical glass also includes colored optical glass, laser glass, quartz optical glass, anti radiation glass, ultraviolet infrared optical glass, fiber optical glass, acoustooptic glass, magneto-optical glass and photochromic glass. Optical glass can be used to manufacture lenses, prisms, mirrors and windows in optical instruments. The components composed of optical glass are the key components in optical instruments.

The glass originally used to make lenses is the bumps on ordinary window glass or wine bottles. The shape is similar to the “crown”, from which the name of crown glass or crown plate glass comes. At that time, the glass was uneven and foam. In addition to the crown glass, there is another kind of flint glass with high lead content. Around 1790, Pierre Louis junnard, a Frenchman, found that stirring glass sauce could make glass with uniform texture. In 1884, Ernst Abbe and Otto Schott of Zeiss established Schott glaswerke Ag in Jena, Germany, and developed dozens of optical glasses within a few years. Among them, the invention of barium crown glass with high refractive index is one of the important achievements of Schott glass factory.

Optical glass is mixed with oxides of high-purity silicon, boron, sodium, potassium, zinc, lead, magnesium, calcium and barium according to a specific formula, melted at high temperature in a platinum crucible, stirred evenly with ultrasonic wave to remove bubbles; Then cool down slowly for a long time to avoid internal stress in the glass block. The cooled glass block must be measured by optical instruments to check whether the purity, transparency, uniformity, refractive index and dispersion index meet the specifications. The qualified glass block is heated and forged to form optical lens rough embryo.