RU31003U1 - Fast lens - Google Patents

Description

The proposed utility model relates to the field of lenses for night vision devices. Night vision devices make it possible to consider the surrounding space in low and low light conditions.

As an energy receiver, an electron-optical converter of the second generation (EOF) is used - a device that amplifies weak light signals incident on it by 10 to 10 times.

It is known that the lenses used for devices of this type should have the largest possible relative aperture and, at the same time, for convenience, a large field of view, which leads to a rather complicated design of the lens optics circuit. Since the spectral sensitivity of modern image intensifiers covers a wide spectral range of wavelengths - from X 0.4 μm to .9 μm, the task is to achieve a high degree of correction of mono- and chromic aberrations throughout the image field 1, 2, 3, 4, 5.

Closest to the claimed scheme is a lens 6, with a relative aperture .2, consisting of five components, the first of which is a single positive meniscus with a convex surface facing the object, the second consists

from the positive meniscus, convex

surface to the object, and the negative meniscus facing the concave surface to the aperture diaphragm placed in the air gap between the second and third components, the third component is made in the form of a glued lens facing the concave surface to the aperture diaphragm, the fourth and fifth components are single positive lenses facing steeper surfaces to each other.

A disadvantage of the known lens is as follows.

Despite the fact that the curvature of the field and astigmatism are well corrected in the lens, the aberrations for the point on the axis and for off-axis beams in the meridional and sagittal sections, especially chromatic ones, are very significant, which significantly reduces the image quality.

The main task that the utility model is aimed at is improving image quality by increasing the relative aperture to .1 and expanding the spectral range to

A, 0.4-0.9 microns.

The problem is solved using the proposed fast lens, which, like the prototype, includes five components, the first of which is a positive meniscus facing a convex surface to the object, the second, consisting of a positive and

ftt / 3 f; r

2 negative menisci, the third, made in the form of a glued lens,

facing the concave surface to the aperture diaphragm,

located between the second and third components, the fourth and fifth components are made in the form of biconvex positive lenses facing steeper surfaces to each other.

Unlike the prototype, two components are additionally introduced into the proposed lens, made in the form of positive menisci, one of which is installed between the first and second components, and the other behind the fifth component, while the optical powers of both additional components correspond to the following conditions: 0.10 ffo11. comp.b, 7 0-2090, the optical forces of the first, second and fourth components correspond to the following conditions:

0.30 pho: ф1,2,4 O.ZZfo, in addition, the thicknesses of the first, additional sixth component, fourth and fifth correspond to the following conditions: 0.10 / ph dl, don.comp. 6.4.5 0-12 / ph. and the lenses of the first, fourth and additional component 6, mounted between the first and second components, as well as the positive lenses of the second and third components are made of the same optical material with a refractive index and dispersion coefficient that satisfy the following conditions: 1.74 u 1.75.50 Vd 51, and additional component 7,

installed behind the fifth component, is made of optical material with a refractive index and a dispersion coefficient that satisfy the following conditions:

1.48 pad.Comp. 49

69 UIDOP.KOMP. 71,

where f is the optical power of the corresponding components,

fo - the optical power of the entire lens,

d-thickness of the respective components,

Pa, Vd is the refractive index and glass dispersion coefficient.

The essence of the proposed utility model is that, due to the introduction of additional components made in the form of positive menisci facing a convex surface towards the object, possessing a weak positive force and having radii close in magnitude and identical in sign, and placing one of between the first and second components, and the other after the fifth component, it became possible to correct the aberrations of a wide inclined beam for a sufficiently large spectral range while ensuring a high degree of uniformity of illumination in the image field: - with relative

hole .1 and angular field of view illuminance at

the edge of the field is 63% of the illumination in the center of the image.

Moreover, the introduced additional components practically do not introduce spherical aberration and astigmatism.

 60f

4

In the drawing, in FIG. 1 - presents an optical scheme of a fast lens.

The fast lens contains five components in series, the first of which is made in the form of a positive meniscus 1, with a convex surface facing the object, the second component 2, consisting of positive and negative menisci, the third component 3 is negative, glued from negative and positive lenses, the fourth component 4 and the fifth component 5 are made in the form of biconvex positive lenses.

Two additional components 6 and 7 are introduced into the lens, made in the form of positive menisci, one of which - component 6 is located between components 1 and 2, and the other component 7 is installed behind component 5. In the air gap between the second component 2 and the third component 3 is located aperture diaphragm 8.

Optical power of optional components 6 and 7,

comply with the following conditions:

0.10 pho dop. Comp. 6.7 0-20 pho, the optical powers of the first, second, and fourth components correspond to the following conditions:

O.ZOfo ф1,2,4 .35 фо, in addition, the thicknesses of the first, additional 6, fourth and fifth components correspond to the following conditions: 0.10 / фо di.additional set 6.4.5 .12 / фо, and the lenses of the first, fourth and an additional component 6 mounted between the first and second components, as well as the positive lenses of the second and third components are made of

the same optical material with a refractive index and a dispersion coefficient that satisfy the following conditions: 1.74 nj 1.75, 50 Vd 51, and the additional component 7 installed behind the fifth component is made of optical material with a refractive index and dispersion coefficient that satisfy the following conditions:

1.48 Payd.Comp. 49 69 Vdaon.KOMn. 71,

where f is the optical power of the corresponding components, ph is the optical power of the entire lens, d-thickness of the corresponding components, nd, Vd is the refractive index and glass dispersion coefficient.

The proposed lens works as follows.

The front group of lenses located in front of aperture diaphragm 8 and consisting of the first three components 1, 6, and 2 forms a weak positive system, which has positive distortion, significant negative astigmatism and field curvature, but it also reduces the aperture by a factor of 2.5 for the next group of lenses, located behind aperture diaphragm 8, consisting of components 3, 4 and 5. This group of components, which has significant optical power, works with a linear magnification close to (.5 and completely corrects aberrations for the center point of the item. Seventh component, possessing

. 6

low optical power, practically does not change the aberration for the axial point, but compensates for the coma and the positive curvature of the field, ensuring uniform image quality throughout the field.

The proposed scheme provides a fast lens with a relative aperture .1 for sufficiently

large spectral range (A.0.4-0.9 μm) upon reaching

a high degree of uniformity of illumination and image quality across the field.

The results of the calculation of a specific lens variant with a focal length, relative aperture .1 and angular

field views of 2 ° to 24 ° are given in the Appendix.

The proposed lens can be used in night vision devices, where increasing the relative aperture, expanding the spectral range and ensuring uniform image quality throughout the field significantly improves the operational properties of the device.

1. Patent 2. Patent 3. Patent 4. Patent 5. Patent 6. Patent sources US INFORMATION No. 4,448,497 M. Cl. G 02 B 9/62 USA No. 4,443,070 M. Cl. G 02 B 9/62 GDR No. 214946M. Cl. G 02 In Japan 11/34 No. 49-23891 M. Cl. G 02 In 9/62 of France No. 2119088 M. Cl. G 02 B 11/00 USA No. 4 363 643 M. Cl. G 02 B 9/62 - prototype. System-OB-V F

Axial

Radii dist.

CURVES

6.600

4,000

6.870

. 060

11.900 1.500

11. 000 8. 500

3.000 16. 000

. 060

7. 000

. 060

7.000

4,000

8.000 ITEM: Fell, BRAIA DIAFR. : ND Relative Relative Relative

System-OB-V F 60 1. 1

Pa.raxial characteristics F F 3F -61, 06064 61. 06064 23. 89970

S S S G (diopter) (MM) (MM) 0. 00000 20. 31015 20. 31015 System-OB-V F 60 1. 1 Beam dimensions 0 27. 73 27. 73 -. 45126 -. 45126 58.472

Refractive indices

Illuminated Marks of height drained L

70,000. 45000.90000

1.7759951.73053

1.7759951.73053

1.7759951.73053

1.695821, 65509

1.7 714091.67087

1.7759951 73053

1, 759951.73053

1.59999. 58009

1.4494791.48062

OPAL-PC

Work-RT

3H

SF

3H -40. 75049 84.960330.31015

SP

SF

(diopter)

(MM)

-61. 06064

58. 47221 -9. 27275

OPAL-PC Operation-RT 60 1. 1 2Vi 24 FILE MAiST.OV 2/12/2002 11: 02 ORAT.-PC CONSTRUCTION PARAMETERS OF THE OPTICAL SYSTEM size U. 00000 30. OOOdptr from input. pupil size Y 12. 50,000 (mm) 31. 000 (named after Gauss Square 8 3D. 0000 (mm) diaphragm height 15. 1000 (mm) size of the item.: 1.000. 707 upper vignetting. 000. 000 lower vignetting:. 000. 000 11Ри (.) LIFE -9. 273. 000. 000 100. 0 100. 0

System-OB-V G 60 1. 1 Aberrations of off-axis beams

Output coordinates Radius ()

I y -, V

LU

Sagittal section Beam 1. 000 48. 40 -12. 84. 02491 - 01807 866 40. 78 -12. 41. 01518 -. 02024

-. 01521

-. 00329. 707 32.39-12. 03 -. 00785. 500 22. 32 -11 70 -. 01282 Bunch 2

Sz.gittslny section -. 00384. 000 49.71-8. 83. 02204. 686 41. 87 -8. 53 -. 00337. 00484 -. 01175 -. 00103 -. 00186 -. 01387

OPAL-PC

(mm)

DX Dy 2 -

-eleven. 5842

24052 -. 04585. 08158-. 01244

17299 -. 04780. 08076-. 01407

10886 -. 04291. 03136-. 00843

05752 -. 03564. 01035-. 00034

-8. 2213

21581. 00989. 08129. 02580

System-OB-V F 60 1. 1 2W: r24

Frequency contrast response

Polychromatic Spread spectrum Ln. 450 LB. 900). 00 1 00 1. 00 1. 00 1. 00 1. 00

lOfrlib fff

ORA1.-WG

Work-MTF

Claims (1)

A fast lens, comprising five components, the first of which is a positive meniscus facing a convex surface to the object, the second consisting of positive and negative menisci, the third, made in the form of a glued lens, facing a concave surface to the aperture diaphragm located between the second and third components, the fourth and fifth components are made in the form of biconvex positive lenses facing steeper surfaces to each other, characterized in that the lens is additionally introduced The sixth and seventh components are made in the form of positive menisci, the sixth component is installed between the first and second components, and the seventh is behind the fifth component, and the optical powers of the additional sixth and seventh components correspond to the following conditions: 0.10φ ₀ ≤ φ _{add. komp.6,7} ≤ 0,20φ _0, the optical powers of the first, second and fourth components comply with the following conditions: 0,30φ ₀ ≤ φ _1,2,4 ≤ 0,35φ _0, moreover, the thickness of the first additional sixth, fourth and fifth terms correspond to the following: 0,10 / φ ₀ ≤ d _{1, to .komp.6,4.5} ≤ 0,12 / φ _0, a lens of the first, fourth and sixth additional component and the positive lens of the second and third components are made of the same optical material having a refractive index and dispersion coefficient, satisfying the following conditions: 1, 74 ≤ n _d ≤ 1.75, 50 ≤ ν _d ≤ 51, and the additional seventh component installed behind the fifth component is made of optical material with a refractive index and dispersion coefficient that satisfy the following conditions: 1.48 ≤ n _{add. 7} ≤ 1.49 69 ≤ ν _{d add.comp. 7} ≤ 71, where φ are the optical powers of the corresponding components; φ ₀ is the optical power of the entire lens; d is the thickness of the respective components; n _d , ν _d is the refractive index and glass dispersion coefficient.