SU665284A1 - Variable focal length objective - Google Patents

Description

one

The invention relates to optics, and to lenses with variable focal length, and can be applied in color television reporting cameras and photographic devices.

A known lens with a variable focal distance, consisting of four components, in which the first component is fixed positive, the second and third components are negative with the possibility of movement along the optical axis, the fourth component is positive fixed (). The dimensions and weight of this lens are large for use in color television reporting cameras.

The technical solution closest to the invention is a lens with a variable focal distance consisting of four lyses 2. The first component of the lens is positive fixed, consists of hollow glued and single lenses, the second component is negative movable, consists of negative single and glued lenses the third component is a positive movable one made of three positive lenses, the second of which is double-glued, the fourth component is positive fixed, consists of a negative glued link PS, negative meniscus and positive glued lenses.

However, the design of this lens does not allow to transfer an image of an object with large angular dimensions and from close finite distance and does not allow to obtain a large back focal length to accommodate the color sans block does not provide telecentric beam paths in the image space required for uniform color reproduction over the field of view.

The purpose of the invention is to increase the field of view and rear focal length,

reduction of the final focusing distance with the simultaneous obtaining of small dimensions and lens weight.

This goal is achieved in that in a lens with a variable focal length,

containing four components, the first and fourth of which are positive and immobile, and the second negative of a single negative meniscus and a double-glued lens and the third positive of

two-glue and single lenses, mounted for movement along the optical axis, the first component is made of successively two negative and four positive lenses, the second positive

the lens is made in the form of a dzukhskleennogo meniscus, and the fourth component of two negative two-glued lenses, behind which a positive single meniscus, a two-glued lens and a two-glued meniscus are located.

Performing the first component allowed us to increase the Field of View of the lens and reduce the final focusing distance, and filling the fourth component provided a close to telecentric course of the rays in the image space and an increase in the back focal length.

The drawing shows the optical layout of the Lens.

A lens with a variable focal length contains four components 1-4, of which components 1 and 4 are non-movable, components 2 and 3 have the ability to move along the optical axis. The first component of the object consists of lenses 5-11, of which lenses 8 and 9 are glued, the fourth component is made of lenses, of which lenses 12 and 13, 14 and 15, 17 and 18 form three glued lenses 21, 22, 23, respectively, and lenses 19 and 20 - glued meniscus 24.

This system design allowed the creation of a variable focal length lens with a large initial field of view angle (67 °), a shorter focusing distance (0.5 m) and an increased rear focal length, while at the same time the lens has a small size and weight with satisfactory quality an image that allows it to be used in portable reporting chambers.

Formula of gain

A lens with a variable focal length, containing four components, the first and fourth of which are positive and stationary, and the second is negative of a single negative meniscus and a two-glued lens and the third is a positive of a two-glued and single lenses, which are mounted with an optical axis that differs the fact that, in order to increase the field of view and rear focal length, to reduce the final focusing distance with a simultaneous decrease in size and weight, the first component is made and two consecutive negative and four positive lens, said second positive lens is formed as a meniscus dvuhskleennogo,

and the fourth component consists of two negative two-glued lenses, behind which are located a positive single meniscus, a two-glued lens, and a two-glued meniscus.

Information sources,

taken into account in the examination

1. The patent of Germany No. 1289327, cl. 42h 6/02, 1970.

2. Authors certificate of USSR L 251858, cl. G 02B 1: 5/16, 1968.

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