RU2053530C1 - Objective with removed entrance pupil - Google Patents

Abstract

FIELD: optical instrument engineering. SUBSTANCE: objective has five components. The first one is made in form of positive double-glued lens. The second one is single biconcave lens. The third component is single positive lens. The fourth one is biconvex lens. The fifth positive component is glued of biconcave and biconvex lenses. Entrance pupil of objective is removed in relation to its first surface, and aperture diaphragm is disposed in the objective. EFFECT: improved reliability of operation. 2 dwg, 1 tbl

Description

 The invention relates to optical instrumentation, namely to lenses with a remote pupil, and can be used to build a television survey complex.

A known lens with a remote entrance pupil having high image quality [1] The lens contains five components: the first single negative meniscus, the second positive double-glued, the third and fourth positive menisci, the fifth positive and glued from a biconvex and negative meniscus lenses. The lens has a relative aperture of 1: 5.6, an angular field of 20 ^° . The small relative aperture of the lens does not allow constructing an optical device based on it, operating in twilight conditions of illumination.

 The closest technical solution to the invention is an optical system [2] containing five components: the first single, positive lens, the second biconcave lens, the third positive meniscus facing concavity to the object, the fourth positive lens glued from biconvex and meniscus lenses, the fifth is made in the form of a single negative meniscus convex to the subject. The entrance pupil of the optical system is located near the first surface of the first component.

The optical system has a relative aperture of the order of 1: 5.6 and an angular field of 20 ^° . A small relative aperture prevents the construction of a television complex based on this optical system that operates in twilight lighting conditions. The absence of a pupil does not allow placing the light control device in it, which is necessary to maintain a constant level of illumination of the image, combined with the screen of a television camera.

 The aim of the invention is to increase the relative aperture while increasing the angular field and removing the entrance pupil.

 This goal is achieved by the fact that in the lens with a remote entrance pupil containing five components, the first of which is positive, the second biconcave lens, the third positive meniscus facing concavity to the object, the fourth positive lens and the fifth meniscus facing concavity to the image, the first component is made in the form of a double-glued lens, the fourth in the form of a single biconvex lens, and the fifth meniscus, made positive, glued from a biconvex and biconcave lens.

 Figure 1 presents a schematic optical diagram of a lens with a remote entrance pupil; figure 2 aberration of the lens.

 The lens contains five components from lenses 1-7. The first component is a positive lens glued from biconvex and plano-concave lenses 1 and 2. The second component is a single biconcave lens 3. The third component is a single positive meniscus 4. The fourth biconvex lens 5. The fifth component is positive and glued from biconvex 6 and biconcave 7 lenses. An aperture diaphragm 8 is placed in front of the lens in the plane of its entrance pupil.

The lens has the following optical characteristics: focal length 14 mm, relative aperture 1: 1.4, linear field of view 2 y '11 mm (angular field 43 ^° ). The lens is achromatized in the spectral region from 450 to 750 nm and corrected for a wavelength of λ 546 nm. The entrance pupil of the lens is 0.5 mm from the first surface.

 The table shows the design parameters of the lens.

The diameter of the scattering circle at a point on the axis is 0.033 mm and the transverse coma does not exceed 0.17%. For a field point y 'of 3.05 nm, longitudinal astigmatism does not exceed 0.03 mm and distortion does not exceed 2%. In the zone of 0.8 of the angular field ( y '4.4 mm) astigmatism and distortion do not exceed 0.06 mm and 5% respectively
The achieved correction of lens aberration provides a high contrast transfer coefficient within the entire angular field. At a spatial frequency of 40 mm ^-1 in the center of the field, the contrast transfer coefficient is T 0.72. In the zone equal to 0.8 of the angular field, the coefficient T is 0.51 in the meridional plane and 0.57 in the sagittal plane.

 The proposed lens with a remote entrance pupil was used to build a fast optical-mechanical device for panoramic panoramic viewing of a television complex operating in a wide range of illumination levels at the entrance pupil, from 30 to 150,000 lux. To maintain constant illumination on a television camera in the plane of the remote entrance pupil placed a light control device from an amplitude filter and an adjustable diaphragm. Stand-alone placement of the dimming device provided ease of assembly, alignment of the lens and control of its optical parameters. The presence of a remote entrance pupil also determined the minimum dimensions of the protective glass and the block of prisms.

Claims (1)

 LENS WITH EXTENDED ENTRANCE PUPIL, containing five components, the first of which is positive, the second is a biconcave lens, the third is a positive meniscus facing concavity to the subject, the fourth is a positive lens and the fifth is the meniscus facing concavity to the image, characterized in that the first component made in the form of a double-glued lens, the fourth in the form of a single biconvex lens, and the fifth meniscus is made positive, glued from a biconvex and biconcave lens.

Images