SPECTROMETER LENS WITH OFFSET PUPIL Russian patent published in 2025 - IPC G02B13/14 

FIELD: optics.

SUBSTANCE: invention relates to optical instrument-making and can be used in spectrometers. Lens of the spectrometer with an offset pupil consists of four elements. First element is a single plane-convex lens, the focal distance f1 of which satisfies condition 1.7<f1/f13<2.2, where f13 is focal distance of group consisting of first three elements. Second and third elements are glued together and form a composite lens whose focal distance f23 satisfies the following conditions: 0.35<f23/f13 and 2.21<n3+0.0176V3<2.27, where n3 is the refraction index of the material of the third element, v3 is the Abbe index for the material of the third element for spectral line d (0.5875618 mcm). Fourth element has a nonzero optical power and is a plane-concave lens whose focal distance f4 satisfies condition 0.85<|f4/f13|<1.15.

EFFECT: lens of the spectrometer with an extended pupil has improved performance characteristics with high image quality in the near infrared range.

1 cl, 6 dwg, 2 tbl