LENS Russian patent published in 2010 - IPC G02B9/34 

FIELD: physics.

SUBSTANCE: lens comprises four components and aperture diaphragm arranged in front of the first component. The first component is a double-glued lens that consists of convexo-convex and concavo-concave lenses. The second component is a double-glued meniscus that consists of convexo-convex and concavo-concave lenses. The third component is a convexo-convex lens. The fourth component is a negative meniscus inverted with its concave surface to space of objects. Distance between the second and third, third and fourth components makes at least 0.38 and 0.2 of lens focus distance accordingly. Convexo-convex lenses of the first, second and third components are arranged of glass with refractory index of at least 1.61. Negative meniscus of the fourth component is made of glass with refractory index of at least 1.8. Difference of Abbe number of convexo-convex and concavo-concave lenses of the first component makes at least 25.

EFFECT: higher image quality.

6 dwg