Optical glass, preform, and optical element

Abstract

The present invention provides optical glass with a refractive index (nd) and Abbe number (vd) within a desired range, and preferably used for chromatic aberration correction, and a lens preform using the optical glass. The optical glass contains B203 component and component F in the composition converted to oxide. The preform and an optical element are formed by the above optical glass.

Description

technical field [0001] The present invention relates to optical glass, preform and optical element. Background technique [0002] Optical systems such as digital cameras and photographic equipment, to varying degrees, include bleeding known as aberrations. This aberration is classified into monochromatic aberration and chromatic aberration, and especially chromatic aberration strongly depends on the material properties of lenses used in the optical system. [0003] Usually, chromatic aberration is corrected by combining a low-dispersion convex lens and a high-dispersion concave lens, but this combination can only correct aberrations in the red and green regions, leaving aberrations in the blue region. The aberration of the irremovable blue region is called secondary spectrum. In order to correct the secondary spectrum, it is necessary to perform an optical design that adds the movement of the g-line (435.835 nm) in the blue region. At this time, the partial dispersion rat...

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Problems solved by technology

[0003] Usually, chromatic aberration is corrected by combining a low-dispersion convex lens and a high-dispersion concave lens, but only the aberrations in the red and green regions can be corrected by the above combination, and the aberrations in the blue region remain

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