SU473145A1 - Projection three-component lens - Google Patents

Description

(54) PROJECTION THREE-COMPONENT LENS

one

The invention relates to optical instrumentation and can be used, for example, in precision measurement systems for processing photographs from bubble chambers.

A three-component telecentric objective beam is known, comprising a front component in the form of a single negative meniscus reversed to the image plane, an internal positive component of a symmetrical type, and a rear single positive component located in close proximity to the image plane. However, its structural complexity is noted. In addition, the presence of a large number of lenses in a known lens increases the light loss and makes it difficult to assemble and adjust the lens.

The proposed lens is characterized in that the internal component is made in the form of a single two positive and negative lenses located between them, and the positive component in the form of a single meniscus with its concavity facing the image plane. In this case, the ratio of the optical powers of the components satisfies the condition

I I: 2: 1: 2 // g: -,

where n is the refractive index of the material of the first and third components, and the distance

between the main planes of the front and inner components is chosen equal to n-1. Such an embodiment of the lens provides a high image quality with a significant simplification of the lens design.

The drawing shows the optical layout of the proposed lens.

The lens consists of three components (front negative 1, internal 2 n positive 3). The front component is made in the form of a meniscus with a concavity facing component 2, which is a three-lens system. In this case, the internal component consists of two identical

positive lenses 4 and 5 and located

between them is a double-curved lens 6, i.e.

is a strictly symmetric

trip.let, working with the increase-1-.

The positive component in the lens is made in the form of a meniscus with a concavity facing the image plane 7.

The distance between the main planes of meniscus 1 and component 2 is chosen equal to

- 1 (is the refractive index of the material of the first and third components), which makes it possible to arrange the concave surface of the meniscus 1 conceptually to the entrance pupil of 8 comg per 2, i.e., to ensure the isoplanatism of the meniscus 1.

The ratio of the optical powers of the components must satisfy the condition / ф1 /: ф2:: 2 / ": 1 /". The fulfillment of this condition in combination with the isoplanatism of the meniscus 1 and the symmetry of the internal component 2 ensures the elimination of the curvature of the image without introducing coma and assigmatism. Since the triplet 2, due to its symmetry, does not introduce distortion either, and the distortion introduced by meniscus 1 can be corrected by an appropriate form of the positive component 3, the proposed lens has a small distortion across the entire field, i.e. it is orthoscopic.

Chromatic aberrations, if necessary, can be directed in a known manner - the selection of lens materials.

Subject invention

A three-component projection lens with a telecentric beam path, containing the front component in the form of a single negative meniscus, facing by its concavity to the image plane, the internal positive component of a symmetric type and the rear positive single component,

located in close proximity to the image plane, characterized in that, in order to simplify the construction, the internal component is made of a single two positive and located between

them a negative lens, and the rear component is made in the form of a single meniscus, facing by concavity to the image plane, while the ratio of the optical forces of the front, internal and rear components

respectively, equal to l: Vn-Vn, and the distance between the main planes of the front and inner component is chosen -1, where n is the refractive index of the material of the first and third components.

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