RU2351968C1 - Wide-angle objective with large lens aperture - Google Patents

Abstract

FIELD: physics; optics.

SUBSTANCE: objective contains seven optical components and aperture diaphragm located between fifth and sixth components. First component - positive, second - subzero, executed in the form of meniscus converted by incurvation to image. Third - subzero, and fourth - subzero also is conglutinated from biconcave and convexo-convex lenses. Fifth is executed in the form of convexo-convex lens. Sixth is executed in the form of single biconcave lens. Seventh is made in the form of the plus meniscus converted by incurvation to the object. After the seventh component the eighth component executed in the form of convexo-convex lens, ninth component - positive and conglutinated of the subzero meniscus converted by incurvation to image, and the plus lens, tenth builder executed in the form of the subzero meniscus, converted by protuberance to the image, and the eleventh component executed plus and conglutinated from convexo-convex and biconcave lenses are in addition entered.

EFFECT: increase of angular field of vision of objective, angular aperture magnification, improvement of image quality.

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Description

The invention relates to wide-angle lenses with a large relative aperture and can be used, for example, with charge-coupled devices (CCD) to obtain visual information about the object observed through the lens.

A wide-angle telephoto lens [1] is known, including five components, the first of which is a positive meniscus facing a convex surface to the object, the second and third are negative menisci, the fourth is glued from a negative meniscus and a biconvex lens, and the fifth component is glued from a positive and negative meniscus and the sixth component is a biconvex lens. The lens has good aberration correction, a significant angular field of view in water 2ω = 90 ° (in air 2ω = 141 °).

The disadvantages of this lens are: insufficient relative aperture (1: 2.8).

Known fast lens "Electron-1" [2], containing eight components, the first of which is glued from a negative meniscus and a biconvex lens, the second is a biconvex lens, the third is a positive meniscus, the fourth is glued from a positive and negative meniscus, fifth is a meniscus, sixth is a positive meniscus, the seventh is a biconvex lens, and the eighth is a biconcave lens. The lens has a large relative aperture (1: 0.75).

The disadvantage of the lens is the small field of view (2Y = 180 mm) and a significant deterioration in image quality when moving from the center to the edge of the field of view (from 0 mm to 180 mm).

A known lens [3], which contains seven optical components, the first two of which are negative menisci, the third is glued from a biconcave and biconvex lenses, the fourth is a biconvex lens, the fifth is glued from a negative and biconvex lens, the sixth is made in the form of a biconvex lens, and its first surface along the optical radiation is made non-spherical, and the seventh component is made in the form of a plane-parallel plate. The lens has a large relative aperture (1: 0.8), a significant angle of field of view (2ω = 62.3 °).

The disadvantages of the lens are: insufficient field of view angle, the presence of a low-tech lens with a non-spherical surface.

The article [4] sets out the principles for constructing schemes of wide-angle lenses. A technique for choosing a circuit diagram of the lens corresponding to the given technical parameters is proposed. The author has proposed photographic and projection lenses developed according to the proposed technique. As a basic system, a planar lens scheme was adopted. Its disadvantage is poor light distribution. The basic system was supplemented with corrective elements of wide-angle lenses "Mir" and "Russar". By introducing correctional-power lens components into the base system, the main lens planes were taken out in the direction of the image plane to increase S ′ F ′ and the value of negative distortion was reduced. Created by this technique and closest to the claimed invention in its technical essence is the construction of a photographic lens (Fig. 1), mentioned in the article.

The copyright certificate for the invention was obtained for this lens [5]. The lens contains an aperture diaphragm and seven optical components, of which the first is positive, the second and third are negative menisci facing the concavity to the image, the fourth component is positive, the fifth is the negative meniscus facing the concavity to the image, and the sixth is the positive meniscus facing the concavity to object and glued from a biconcave and biconvex lens, the seventh component is biconvex, and the aperture diaphragm is located between the fifth and sixth components. The lens with the stated characteristics has good image quality, good uniformity of light distribution over the image. The disadvantages of the lens are: insufficient angular field of view (2ω = 53 °), insufficient value of the relative aperture (1: 1.4).

The latter invention is adopted as a prototype.

The technical result of the invention is to increase the angular field of view of the lens, increase the relative aperture, improve image quality.

The specified technical result is achieved in that in a wide-angle lens with a large relative aperture containing an aperture diaphragm and seven optical components located along the radiation from the object to the image, the first of which is positive, the second is negative, made in the form of a meniscus facing concavity to image, the third negative, fourth and fifth components, the sixth is negative, the seventh is positive, and the aperture diaphragm is located between the fifth and sixth components, h the fourth component is made negative in strength and glued from two lenses, the first of which is biconcave, the second is biconvex, the fifth component is positive in the form of a biconvex lens, the sixth component is made in the form of a single biconcave lens, the seventh component is made in the form of a meniscus facing concavity to object, and after the seventh component, an eighth component is additionally introduced, made in the form of a biconvex lens, the ninth component, positive in strength and made of glued from two lenses, is not the second of which is the negative meniscus facing concavity to the image, the second is the positive, tenth component made in the form of a negative meniscus convex to the image and the eleventh component is positive in strength and glued from two lenses, the first of which is positive biconvex, the second - negative biconcave.

Figure 1 presents the optical scheme of the proposed lens, and figure 2 is a graph of frequency-contrast characteristics that show a significant improvement in image quality for the central part of the field of view of the lens (Y1 to Y5), with virtually no deterioration in image quality for extreme and medium parts of the visual field (from Y2 to Y4). Where Y1 = 0, Y2 = Ymax, Y3 = 0.7Ymax, Y4 = 0.5Ymax, Y5 = 0.4Ymax.

The proposed wide-angle lens with a large relative aperture contains eleven components located along the radiation from the object to the image, the first 1 of which is positive, the second 2 is negative, made in the form of a meniscus facing concavity to the image, the third 3 is negative, the fourth 4 and the fifth 5 components, the sixth 6 is negative, the seventh 7 is positive, and the aperture diaphragm 12 is located between the fifth 5 and sixth 6 components. The fourth 4 component is negative in strength and glued from two lenses, the first 4A of which is biconcave, the second 4B is biconvex, the fifth 5 component is positive in the form of a biconvex lens, the sixth component 6 is made in the form of a single biconcave lens, the seventh 7 component made in the form of a meniscus facing concavity to the object. After the seventh 7 component, the eighth 8 component, made in the form of a biconvex lens, the ninth 9 component, positive in strength and glued from two lenses, the first 9A of which is the negative meniscus facing the concavity to the image, the second 9B is positive, the tenth 10 is additionally introduced the component made in the form of a negative meniscus convex to the image and the eleventh 11 component made positive in strength and glued from two lenses, the first 11A of which is positive biconvex, oraya 11B - negative biconcave.

The lens works as follows. The luminous flux from the object sequentially passes all the components to the aperture diaphragm 12, which cuts out the useful part corresponding to the relative aperture from the entire stream, passes all the components after the aperture diaphragm 12 and forms an image in the image plane of the lens in which the optical radiation receiver is mounted, for example, CCD matrix.

Modified and additional components of the lens compared to the prototype allow to solve the following tasks: performing the fourth 4 components with a negative force reduces the light diameter of the lenses located in front of it, while increasing the angular field of view of the lens, and also makes a positive value for the aberration of the field curvature in the overall contribution components of the lens, and the implementation of this component bonded from two lenses 4A and 4B allows you to adjust the spherochromatic aberration and chromatism aberration increased of reading. The implementation of the fifth 5 component biconvex allows you to adjust the higher orders of spherical aberration. The implementation of the sixth 6 component in the form of a single biconcave lens allows you to adjust spherical aberration, curvature of the field of view, astigmatism and coma aberration. The implementation of the seventh 7 component in the form of a positive meniscus facing concavity to the object, allows you to adjust the aberration of astigmatism and to develop a relative aperture of the lens. The eighth 8 component, made in the form of a biconvex lens, develops a relative aperture of the lens. The ninth 9 component, positive in strength and made by gluing from two lenses, the first 9A of which is the negative meniscus facing the concavity to the image, the second 9B is positive, corrects aberrations of spherochromatism, spherical, and chromaticity increase. The tenth 10 component, made in the form of a negative meniscus, convex to the image, corrects the curvature and astigmatism of the visual field. And the eleventh 11 component, made positive in strength and glued from two lenses, the first 11A of which is positive biconvex, the second 11B - negative biconcave corrects distortion aberrations, position chromaticity and magnification, and aberrations of wide inclined beam beams.

The applicant has developed a prototype lens having a focal length of 21.7 mm, an angular field of 2ω = 82 °, a relative aperture of 1: 1.06.

The applicant made prototypes of the proposed lens, which confirmed the improvement of the required characteristics.

Information sources

1. A.S. USSR No. 1649492, 1989, Wide-angle hydro lens.

2. Photographic optics, D. Volosov, M., Art, 1978, pp. 458-459.

3. US Patent No. 5724195, 08.16.1996, Fast super wide-angle lens system.

4. Article: Synthesis of a fast wide-angle photographic lens with an enlarged rear focal segment, author Kozodoy VV, “Instrument-Making”, State. RF Committee on Higher Education, News of Higher Education Institutions, Volume 37, February 1994, No. 2, pp. 72-74.

5. A.S. USSR No. 1663596, 1989, Fast lens (prototype).

Claims (1)

A wide-angle lens with a large relative aperture, containing an aperture diaphragm and seven optical components located along the radiation from the object to the image, the first of which is positive, the second is negative, made in the form of a meniscus facing concavity to the image, the third is negative, fourth the fifth component, the sixth is negative, the seventh is positive, and the aperture diaphragm is located between the fifth and sixth components, characterized in that the fourth component is made it is negative in strength and glued from two lenses, the first of which is biconcave, the second is biconvex, the fifth component is positive in the form of a biconvex lens, the sixth component is made in the form of a single biconcave lens, the seventh component is made in the form of a meniscus facing concavity to the object, after the seventh component, the eighth component, made in the form of a biconvex lens, the ninth component, positive in strength and made of glued from two lenses, the first of which is negative, is additionally introduced enisk facing concave to the image, the second - positive, tenth component configured as a negative meniscus which is convex to the image, and the eleventh component configured positive strength and glued of two lenses, the first of which the positive biconvex, the other - negative biconcave.

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