VARIABLE FOCUS LENS, OPTICAL DEVICE, AND ZOOM LENS MANUFACTURING METHOD Russian patent published in 2019 - IPC G02B15/20 G02B15/16 

FIELD: optics.

SUBSTANCE: zoom lens comprises four lens groups, the first, third and fourth being positive, the second being negative. First lens group includes a lens bonded from negative and positive lenses, and a positive meniscus facing the object with its convex surface. All four groups move and the aperture stop moves with the third lens group. In the first, second, third versions νdp1 > 85.0, where νdp1 is the Abbe number of the positive lens of the first lens group located closer to the object. In the first version νdp2 > 70.0, where νdp2 is the Abbe number of the positive lens of the first lens group located closer to the image. In the second - the third lens group includes a positive lens, a lens bonded from positive and negative lenses, and a positive lens. In the third - the fourth lens group includes a lens bonded from positive and negative lenses. In the fourth version νdp1 ≥ 95.0, 0.05 < (- fG2) / fG1 ≤ 0.105, fG1, fG2 are the focal lengths of the first and second lens groups.

EFFECT: technical result is an increase in the zoom ratio, compactness and improved image quality and zooming.

13 cl, 24 dwg, 4 tbl