RU52489U1 - LIGHT LIGHT - Google Patents

Abstract

A fast lens can be used in night vision devices. The lens contains three components, the first of which, along the rays, is a two-lens gluing of biconvex and biconcave lenses, the second and third components are positive and negative menisci, convex to the object, and certain ratios of the radii of the biconvex lens and the positive meniscus are fulfilled.

EFFECT: obtaining a lens with a relative aperture of 1: 1.6.

Description

The utility model relates to the field of optoelectronic technology and can be used in night vision devices.

A well-known photographic lens is a high-aperture four-lens anastigmat “Tair-11A” containing three components, the first of which along the rays is a two-lens gluing of biconvex and biconcave lenses, the second and third components are positive and negative menisci, convex to the object (Yakovlev A.F. "Optical Instruments. Catalog", "Lenses", volume 12, part II, "Engineering" 1978, p. 19). The relative aperture of the lens is 1: 2.8, the focal length is 135 mm, the resolving power in the center is 44 ln / mm, along the edge of the field is 24 ln / mm.

A similar lens of the “Tair” type is known (Pat. RU 2 239 212 C2, published on October 27, 04), which differs from the above in that the second lens in the gluing is made concave and, moreover, the following relationships hold:

The relative aperture of such a lens can reach 1: 2.2, as, for example, with the Tair-41 lens (A. Yakovlev, “Optical Instruments. Catalog”, vol. 12 part I, “Mechanical Engineering” 1978, p. .75).

The closest to the proposed utility model is the Tair-11A lens (see above).

The objective of the utility model is to increase the lens aperture.

The technical result due to the task is achieved by the fact that in a fast lens containing three components, the first of which along the rays is a two-lens gluing of biconvex and biconcave lenses, the second and third components are positive and negative menisci, convex to the object, the following ratios:

where

R ₁ and R ₂ are the radii of a biconvex lens, R ₄ and R ₅ are the radii of a positive meniscus.

The indicated ratio of the radii can increase the lens aperture and achieve a relative aperture of 1: 1.6.

The drawing shows an optical diagram of the lens. It has three components: 1 - two-lens gluing of biconvex and biconcave lenses, 2 - positive meniscus, convex to the object, 3 - negative meniscus, convex to the object.

The design parameters of the lens embodiment are as follows:

Radii Thickness Glass mark Surface diameters R1 = 121.9 75 d1 = 17.0 T K14 R2 = -83.56 74,4 d2 = 4.2 TF5 R3 = 731.1 72.5 d3 = 6.4 R4 = 57.81 69.6 d4 = 14.25 T K14 R5 = 190.55 66.1 d5 = 23.45

R6 = 25.0 40.5 d6 = 9.15 K8 R7 = 17.579 30,4

Ratios:

R ₁ / IR ₂ I = 1.45

IR ₂ I / R ₄ = 1.45

R ₄ / R ₅ = 0.3

This lens has the following parameters:

- focal length 120.0 mm: - relative hole 1: 1.6; - diameter of the entrance pupil 75 mm; - angle of view 7 ° 30 ' - linear field of view 18.0 mm

The image quality of the lens is characterized by its frequency response.

So, for a frequency of N = 20 ln / mm, the image contrast is of the order of:

- for a point on the axis - 0.8 - for the middle of the field of view - 0.6 (meridional and sagittal section) - for the edge of the field of view - 0.4 (meridional and sagittal section)

The design parameters of other versions with extreme or close to them values of the declared ratios of the radii are as follows:

Option 2

Radii Thickness R ₁ = 136.9 d ₁ = 17.0 R ₂ = -76.06 f '= 120.2 mm d ₂ = 4.2 rel. open 1: 1.6 R ₃ = 1100.1 d ₃ = 6.4 R ₄ = 57.81 d ₄ = 14.25 R ₅ = 220.55 d ₅ = 23.45 R ₆ = 25 d ₆ = 9.15 R ₇ = 17.579

Option 3

Radii Thickness R ₁ = 99.23 d ₁ = 16.86 R ₂ = -94.27 f '= 124.3 mm d ₂ = 3.0 rel. open 1: 1.6 R ₃ = 474.64 d ₃ = 6.826 R ₄ = 58.3 d ₄ = 15,225 R ₅ = 150.72 d ₅ = 24.87 R ₆ = 26.6 d ₆ = 8.55 R ₇ = 18.3

Glass brands and surface diameters are the same as the main version.

Image quality (HRX) for a frequency of N = 20 ln / mm is:

Option 2 Option 3 - for axis point 0.75 0.545 - for the middle of the field of view (meridional and sagittal section) 0.46 and 0.56 0.46 and 0.49 - for the edge of the field of view (meridional and sagittal section) 0.38 0.36 and 0.42

The lens is designed to work in night devices. It gives an image of objects on the photocathode of the image intensifier tube. Therefore, it is designed for all variants together with a protective plate of a tube with a thickness of 1 mm and a plate of a photocathode with a thickness of 1.2 mm located near the focal plane of the lens.

Claims (3)

A high-speed lens containing three components, the first of which along the rays is a two-lens gluing of biconvex and biconcave lenses, the second and third components are positive and negative menisci, convex to the object, characterized in that the relations 1.0 <R ₁ / | R ₂ | <1.8 1.2 <| R ₂ | / R ₄ <1.6 0.25 <R ₄ / R ₅ <0.45, where R ₁ and R ₂ are the radii of a biconvex lens, mm; R ₄ and R _{5 are the} radii of a positive meniscus, mm.