WIDE-ANGLE EYEPIECE Russian patent published in 2017 - IPC G02B25/04 

FIELD: physics.

SUBSTANCE: eyepiece contains four optical components. The first negative eyepiece component from the image plane side is made as a plano-concave lens, the second positive one - as a plano-convex lens, wherein the flat surfaces of the lens face the image plane. The third positive component consists of the biconvex and plano-concave lenses glued together. The refractive gluing surface is convex to the exit pupil, and the fourth positive component consists of the negative meniscus lens and the biconvex lens glued together. The refractive gluing surface is concave to the exit pupil. The negative lenses of the first, the third and the fourth eyepiece components are made of glass such as "heavy flint". The positive lenses of the second and the third components are made of glass such as "extra-heavy crown", the positive lens of the fourth component oriented to the observer's eye, - of glass such as "heavy crown". The eyepiece has a real focus plane at the distance of about 0.17f' from the first flat surface, where mesh or crosshairs can be installed. The eyepiece has an angular view field of 76° (in the exit pupil area), the exit pupil distance from the last ophthalmic lens surface of about 0.49f' and the relative aperture of less than 1:4 with a focal length of 15-25 mm.

EFFECT: improving the image quality of the view field edge zones by reducing the residual aberrations and increasing chromaticity, decreasing the eyepiece aberrations in the exit pupil, which reduces vignetting the view field edge zones and enhances comfort when observing the objects located at the view field edges.

2 cl, 6 dwg, 1 tbl