Optical glass, prefabricated member and optical element

Abstract

The invention aims to provide optical glass which has high refractivity, low chromatic dispersion and relatively high stability, a prefabricated member manufactured by the optical glass, and an optical element. The optical glass comprises the following components by mass relative to total mass of oxides: 8.0-40.0% of B2O3, 15.0-80.0% of Ln2O3, wherein Ln is more than one selected from a set which is composed of La, Gd, Y and Yb. Relative to the mass of the oxides except for an F component, the optical glass comprises 5.0-50.0% of the F component by mass. Furthermore the optical glass has refractivity (nd) in 1.20-1.80, and an Abbe number (nud) in 45-65.

Description

technical field [0001] The invention relates to an optical glass, a preform and an optical element. Background technique [0002] In recent years, the digitalization and high-definition of equipment using optical systems has been rapidly developing. The number of optical elements such as lenses and prisms used in the optical system, and the requirements for reducing the weight and miniaturization of the overall optical system are getting higher and higher. [0003] Among the optical glasses used in the manufacture of optical elements, especially those having a high refractive index (n) of 1.50 or more and 1.80 or less can realize the weight reduction and miniaturization of the overall optical system d ) and a high Abbe number (ν d ) glass with high refractive index and low dispersion becomes very high. In this regard, glass components represented by Patent Documents 1 to 3 are widely known. [0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-06388...

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Problems solved by technology

[0012] However, the glasses described in Patent Documents 1 to 3 have a small partial dispersion ratio even though they have high refractive index and low dispersion, and are not suitable for use as lenses for correcting secondary spectra.

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