OBJECTIVE Russian patent published in 2009 - IPC G02B9/34 

FIELD: instrument making.

SUBSTANCE: invention relates to optical instrument making and can be used in various optical devices, including, TV cameras incorporating a reception matrix. The objective consists of four lenses arranged along the beam, i.e. the first making the biconvex lens, the second making a biconcave lens, the third making a convexo-plane lens, the fourth making a convex-plane lens. The convexo-plane lens thickness-to-objective focal length ratio varies from 0.09 to 0.15. The following ratios exist in this case, i.e. 1.61 < n₁ = n₃ = n₄ <1.63, 1.6 < n₂ <1.673, where n₁, n₂, n₃, n₄ are the parametres of refraction of the material of the first, second, third and fourth lenses for line D. The third air interval-to-objective focal length ratio can make vary 0.001 to 001.

EFFECT: higher-quality image and ease of manufacture.

2 cl, 1 dwg