SU934431A1 - Zoom lens - Google Patents

Description

(54) LENS WITH A VARIABLE FOCUS DISTANCE

one

The invention relates to optical instrumentation, namely photographic lenses, and can be used in various photographic devices, especially optical television transmission cameras, where wide-angle lenses with large magnification of focal length are required.

And there are rigid lenses with variable focal length, containing four components, two external ones of which are fixed, and internal ones are mounted for movement along the optical axis Cl.

These lenses can be used as a whole in a number of cases; however, their optical scheme does not allow obtaining a multiplicity of changes in focal length over 20 sharp deterioration of image quality with an increase in the interval of change in focal distances.

The closest to the present invention is a lens with a large range of focal lengths and a relatively short length, which contains four components, of which the first positive and fourth negative are fixed, the second negative and third positive components are mounted with the possibility of moving along the optical axis, due to the movement of which the focal distance changes, the second component moving along a linear

Claims (2)

10 (screw) guide, and the third along a non-linear cam guide. The first component consists of a two-glued and a single meniscus and a positive pattern installed in front of them, the concavity facing the image plane, the second consists of a negative meniscus and a two-glued lens, supplemented by a negative lens, the third component is made of a double convex glued lens, glued and single meniscus, the fourth component of two glued and a single negative lens G2. The disadvantage of this lens is the fact that the design of its second component does not allow to obtain an angular field of view in the system over and a multiplicity of over 20 due to the sharp increase in field aberrations. The purpose of the invention is to expand the range of changes in focal lengths and increase the angular field of view of the system. The goal is achieved by the fact that in a lens containing a first non-movable component made of two single lenses and a double-glued meniscus installed between them, a third component, a full two dual-glued and single lenses mounted with a possibility of movement along the optical axis, and a fourth component , made of two color-glued and negative lenses installed between them, the second component is made in the form of successively installed negative two-glued meniscus concave toward the flat the image bone, flat-concave, double-glued and single double-concave lenses, the refractive index of the material of the glued lenses exceeding 1.74. The figure shows the optical scheme of the lens. The lens consists of four components 1-4. Component 1 is made from two single lenses 5 and 6 and a double-glued meniscus 7 installed between them. 74. Component 3 consists of two two-glued lenses 11 and 12 and a single lens 13, and component 4 is made of two two-glued lenses 14 and 15 and a single lens 16 located between them. Components 1 and 4 are fixedly mounted, components 2 and 3 are mixed simultaneously along the optical axis moreover, component 2 moves linearly, and component 3 moves along a non-linear cam guide. At the minimum focal distance, the movable component 2 approaches the stationary component 1, and the movable component 3 to the stationary component 4. As the moving components 2 and 3 approach, the focal distance of the system takes on a maximum value. Simultaneous movement of components 2 and 3 ensures the constancy of the image plane for all values of focal lengths. The above construction of component 2 makes it possible to significantly reduce field aberrations and thereby increase the multiplicity of changes in focal lengths to 30 and an angular field of view of ao 680. Claims of the invention A lens with a variable focal distance containing four components, one of which is fixed two single lenses and a double-glued meniscus installed between them, the third component is made of two double-glued and single lenses mounted for movement along the optical axis, and four The second component is made of two double-glued and negative lenses installed between them, characterized in that, in order to expand the interval of change of focal lengths and increase the angular field of view, the second component is made in the form of successively established negative / shielded meniscus facing the image plane to two-glued and single double-coated lenses, and the index of refraction of the material of the glued lenses exceeds 1.74. Sources of information taken into account in the examination 1. The author's certificate of the USSR N 447661, cl. Q 02 B 15/00, 1971. 2. USSR author's certificate number ZZO413, cl. Q 02 B 15/16, 1971 (prototype).