HIGH-APERTURE LENS OBJECTIVE Russian patent published in 2009 - IPC G02B9/64 

FIELD: physics; optics.

SUBSTANCE: objective can be used in devices with a CCD photodetector and a spherical cowling. The objective has two groups of lenses on a beam path consisting of five and three lenses respectively. The first group comprises a first positive single convex-concave lens, fourth positive and fifth single biconcave lens. The second group comprises a sixth lens in form of a single positive meniscus, whose concave side faces the object, a seventh negative lens and an eight positive convex-concave lens, whose convex side faces the object. When the object is placed behind the spherical cowling with displacement from its optical axis, the optical axis of the sixth lens can be displaced from the optical axis of the objective in the direction of the optical axis of the spherical cowling, behind which the objective is placed, by a value Y₆=(0.1-1)·Y, where Y is displacement of the optical axis of the objective from the optical axis of the spherical cowling, and the ratio of focal distances satisfies the expression: f₆=(10-20)·F_ob, where f₆ is focal distance of the sixth lens; F_ob is the focal distance of the objective.

EFFECT: quality image when optical axis of the objective is displaced from the optical axis of the spherical cowling.

2 cl, 1 dwg