RU204540U1 - LENS - Google Patents

Abstract

The utility model relates to optical instrumentation, namely to lenses, and can be used as a lens with the formation of an image on a color CCD matrix and a photodetector. The lens consists of a first biconvex lens installed along the beam path, a negative meniscus glued from a biconvex lens and a biconcave lens, the first single negative meniscus facing the space of objects with a concave surface, the second biconvex lens, the second single negative meniscus facing the space of objects with a concave surface and a spectral dividing unit capable of separating radiation in the spectral range of wavelengths (430 ... 650) nm and radiation with wavelength (1540 ± 30) nm or (1060 ± 30) nm. The aperture diaphragm is located in front of the first biconvex lens. The sum of the optical powers of all single lenses and a double-glazed lens does not exceed 0.001 in absolute value. The distance between the first single meniscus and the second biconvex lens is not less than 0.18 of the lens focal length. The distance from the second biconvex lens to the second single meniscus is not less than 0.22 of the focal length of the lens. The declared lens provides an increase in the field of view, an increase in the scale of the image by increasing the focal length, improving the quality of images in the entire field of view in the spectral range (430 ... 650) nm , reducing the length of the lens from its first surface to the image plane to a value of no more than 1.05 of the focal length of the lens, expanding the functionality of the lens by separating radiation and using two receivers.

Description

The utility model relates to optical instrumentation, namely to lenses, and can be used as a lens with image formation on a color CCD matrix and a photodetector.

Known lens [1] of five components, the first component is made in the form of a biconvex lens, the second component is made in the form of a positive meniscus facing the convex surface of the object space, the third component is a biconvex lens, the fourth component is a biconvex lens and the fifth component is made in the form of a flat - a concave lens facing a flat surface to the space of objects. This lens design provides high quality images in a wide spectral range for spatial frequencies up to 100 mm ^-1 and for a field of view up to 13 °. However, the rear focal length of this lens design is 0.1 of the focal length of the lens, which does not allow placing a spectrum splitting unit on it.

The closest to the proposed lens is the lens [2], which consists of five components. The first component is made in the form of a biconvex lens, the second component is a meniscus glued from a biconvex and biconcave lenses, the third component is made in the form of a positive meniscus facing the convex surface to the space of objects, the fourth component is a negative meniscus facing the convex surface to the space of objects, the fifth component - biconvex lens, and the distance between the first and second components is not less than 0.25 of the focal length of the lens. The prototype has good image quality in the center of the field of view and for a field of view angle of no more than 2W = 5 ° with a lens focal length of up to 100 mm. In this design of the lens, the rear focal length is 0.44 of the lens focal length, which makes it possible to place a spectrum splitting unit on it, and the length of the lens from the first surface to the image plane is 1.45 of the lens focal length. However, when the focal length is increased over 100 mm and the angle of view is over 2W = 5 °, this design does not provide a sufficiently high image quality.

The task of the utility model is to increase the field of view, increase the scale of the image by increasing the focal length, improve the quality of images in the entire field of view in the spectral range (430 ... 650) nm, reduce the length of the lens from its first surface to the image plane to no more than 1.05 focal length of the lens, expanding the functionality of the lens by separating radiation and using two receivers.

The lens contains the first biconvex lens installed along the rays, the meniscus glued from the biconvex and biconcave lenses, the first single meniscus and the second single negative meniscus, as well as the second biconvex lens, unlike the prototype, the second biconvex lens is located between the first single meniscus and the second meniscus, a spectral dividing unit is introduced, located after the second single negative meniscus and made with the possibility of separating radiation in the spectral range of wavelengths (430 ... 650) nm and radiation with a wavelength of (1540 ± 30) nm or (1060 ± 30) nm, aperture a diaphragm located in front of the first biconvex lens, while the glued meniscus is negative, the first single meniscus is negative and faces the space of objects with a concave surface, the second single negative meniscus is directed by the concave surface to the space of objects, the sum of the optical forces of all single lenses and two The lens does not exceed 0.001 in absolute value, the distance between the first single negative meniscus and the second biconvex lens is not less than 0.18 of the focal length of the objective, and the distance from the second biconvex lens to the second single negative meniscus is not less than 0.22 of the focal length of the lens.

The choice of the location of the optical components, the distribution of optical forces between them in such a way that their sum does not exceed 0.001 in absolute value, made it possible to increase the field of view and correct the aberrations of wide oblique beams, thereby improving the quality of images over the field of view. The choice of the distance between the first single negative meniscus and the second biconvex lens located behind it is not less than 0.18 of the focal length of the objective, the choice of the distance from the second biconvex lens to the second single negative meniscus is not less than 0.22 of the focal length of the lens, as well as the implementation of a spectral splitting unit with the possibility of separation of radiation in the spectral range (430 ... 650) nm and radiation with a wavelength of (1060 ± 30) nm or (1540 ± 30) nm and its location after the second single negative meniscus, made it possible to increase the focal length of the lens while decreasing the distance from the first surface of the lens to the image plane to a value of no more than 1.05 of its focal length and improve the quality of images over the entire field and use it both for forming an image on a color CCD matrix and for registering the return radiation of a laser rangefinder on the photodetector site, optically coupled with the spectral-splitting edge spectrode casting block. The offered lens has:

- focal length 150 mm, relative aperture 1: 3, angle of view 2w = 9 °. The entrance pupil 50 mm in diameter coincides with the first surface of the lens. Polychromatic modulation transfer coefficients (T) for spatial frequency N = 45 mm ^-1 at a point on the axis not less than 0.58, at the edge of the field of view 2W = 9 ° not less than 0.4.

FIG. 1 shows the optical scheme of the proposed lens.

FIG. 2 shows the design parameters of the objective lenses and the glass characteristics, where R is the radius of curvature of the lens surfaces, D is the distance between the lens surfaces, n _e is the refractive index of the lens glasses for the e line (λ = 546 nm), v is the Abbe number for the e line.

FIG. 3 shows the graphs of the calculated polychromatic frequency-contrast characteristic (T) for a point on the axis and for a point at the edge of the field of view 2W = 9 °.

The lens (Fig. 1) consists of the first biconvex lens 1 installed in the direction of the beam, a negative meniscus glued from a biconvex lens 2 and a biconcave lens 3, a first single negative meniscus 4 facing the space of objects with a concave surface, a second biconvex lens 5, a second single negative meniscus 6, concave surface facing the space of objects and spectral dividing unit 7, made with the possibility of separating radiation in the spectral range of wavelengths (430 ... 650) nm and radiation with a wavelength of (1540 ± 30) nm or (1060 ± 30) nm. The aperture diaphragm is located in front of the first biconvex lens 1. The objective is designed with a light filter 8, which selects the spectral range (430… 650) nm.

The distance between the first single negative meniscus 4 and the second biconvex lens 5 is 28.4 mm, which is 0.19 of the focal length of the objective, the distance from the second biconvex lens 5 to the second single negative meniscus 6 is 35.15 mm, which is 0.22 focal length of the lens. The sum of the optical powers of the five components is:

ϕ = | ∑1 / f ' _i | = | 1 / 81.68 + 1 / (- 121.15) +1 / (- 103.46) + 1 / 90.41 +

+1 / (- 182.18) | = | -0.0001 |,

where f ' _I is the focal length of the component.

The length of the lens from the first surface to the image plane is 151.9 mm, which is 1.01 of the focal length of the lens.

The graphs of the polychromatic frequency-contrast characteristic for a point on the axis and for a point at the edge of the field of view 2W = 9 °, shown in Fig. 3, confirm that the lens has good image quality over the entire field in the spectral range (430 ... 650) nm and allows you to get a good image on a color matrix with a pixel size of 5.5 µm.

The lens works as follows: a parallel light beam with a field of view angle of 2W = 9 ° passes through the entrance pupil of the objective, 50 mm in diameter, coinciding with the first surface, and, refracting through the surfaces of the first biconvex lens 1, a negative meniscus glued from a biconvex lens 2 and biconcave lens 3, the first single negative meniscus 4, the second biconvex lens 5, the second single negative meniscus 6 falls into the spectro-splitting unit 7, which separates radiation with wavelengths λ = (430 ... 650) nm and radiation with a wavelength of λ = 1540 nm or λ = 1060 nm, passes through the light filter 8, and focuses in the image plane where the CCD matrix is located. A beam of rays with a wavelength of λ = 1540 nm or λ = 1060 nm is focused on the area of the photodetector.

Information sources

1. BY 14572 C1 (Foreign private production unitary enterprise "Beltex Optic" of the company "Saybir Optic" (BY)), published on February 28, 2011.

2. ЕА 007361 В1 (Scientific and Production Republican Unitary Enterprise "LEMT" (BY)), publication 27.10.2006.

Claims (1)

A lens containing a first biconvex lens installed in the direction of the rays, a meniscus glued from a biconvex and biconcave lenses, a first single meniscus and a second single negative meniscus, as well as a second biconvex lens, characterized in that the second biconvex lens is located between the first single meniscus and negative meniscus, a spectral dividing unit is introduced, located after the second single negative meniscus and made with the possibility of separating radiation in the spectral range of wavelengths (430 ... 650) nm and radiation with a wavelength of (1540 ± 30) nm or (1060 ± 30) nm, introduced an aperture diaphragm located in front of the first biconvex lens, while the glued meniscus is negative, the first single meniscus is negative and faces the object space with a concave surface, the second single negative meniscus faces the object space with a concave surface, the sum of the optical forces of all single lenses and two The lenticular lens does not exceed 0.001 in absolute value, the distance between the first single negative meniscus and the second biconvex lens is not less than 0.18 of the focal length of the objective, and the distance from the second biconvex lens to the second single negative meniscus is not less than 0.22 of the focal length of the lens.

Images