What does "optical lens" mean

Optical lenses are lenses made of optical glass. The definition of optical glass is glass that has specific requirements for optical properties such as refractive index, dispersion, transmittance, spectral transmittance and light absorption, and has uniform optical properties. Glass that can change the direction of light propagation and alter the relative spectral distribution of ultraviolet, visible or infrared light. Narrowly defined, optical glass refers to colorless optical glass. In a broad sense, optical glass also includes colored optical glass, laser glass, quartz optical glass, radiation-resistant glass, UV-infrared optical glass, fiber optical glass, acousto-optic glass, magneto-optic glass and photochromic glass. Optical glass can be used to manufacture lenses, prisms, mirrors and Windows in optical instruments. Components made of optical glass are key elements in optical instruments.

Optical glass is made by mixing oxides of high-purity silicon, boron, sodium, potassium, zinc, lead, magnesium, calcium, barium, etc. in a specific formula, melting them at high temperature in a platinum crucible, and stirring them evenly with ultrasonic waves to remove air bubbles. Then, cool it down slowly over a long period of time to prevent the glass block from developing internal stress. After cooling, the glass blocks must be measured by optical instruments to check whether their purity, transparency, uniformity, refractive index and dispersion rate meet the specifications. Qualified glass blocks are heated and forged to form optical lens blanks.