CS255840B1 - Optical system of high-quality lens - Google Patents

Abstract

The solution concerns the creation of an optical system of a high-luminance objective, forming part of a tandem arrangement of objectives for X-ray television technology. It is formed by six optical elements, consisting of seven lenses, arranged so that the first element is formed by a connecting meniscus, the next element is a biconvex lens cemented with a biconcave lens, then follows a biconcave lens, then a biconvex lens and then a biconvex or planoconvex lens and finally a biconcave lens.

Description

The invention relates to an optical system of a high-luminance objective, forming part of a tandem arrangement of objectives for X-ray television technology, where it is used as a secondary objective, following on from the primary collimation objective and mediating the transmission of the image from the screen of the X-ray intensifier to the vidicon of the television camera.

Known lenses of this category with a relative aperture of 1:0.85 usually do not achieve the required uniformity of illumination, or they achieve it at the cost of a decrease in image quality. The relatively large air gap between the tandem lenses has a very adverse effect on the uniformity of illumination of the system. Only the maximum reduction of geometric vignetting of the high-speed lenses used will contribute to improving this situation. In doing so, it is necessary to take into account the ever-increasing requirements for image quality, which most known lenses do not meet.

The task was therefore to design a maximum seven-element, technologically undemanding optical system that would exhibit minimal geometric vignetting at a relative aperture of 1:0.85 and a field of view of 2alpha = 16° and the image quality should be characterized by high contrast for the required frequency of 30 lines per 1 mm. Another condition is to comply with the following dimensional requirements:

The total length of the optical system L < 1^6 f* the secant distance of the lens itself s’j> 0.07 f’, where f’ is the focal length of the optical system.

The correction state of the optical system needs to be optimized for the use of plane-parallel glass with a thickness of d = 2.3 and a refractive index of n = 1.489, which imitates the wall of the scanning tube.

This task is solved by the subject of the invention, which is an optical system of a high-luminance objective, forming part of a tandem arrangement of objectives for X-ray television technology, where it is used as a secondary objective, following on from the primary collimation objective and mediating the transmission of the image from the screen X-ray intensifier to the vidicon of the television camera.

The essence of the invention lies in the fact that this optical system is formed by a connecting meniscus, further cemented member, composed of a biconvex lens and a biconcave lens. Then follows a biconcave lens, another biconvex lens, a biconvex or plano-convex lens and a biconcave lens.

Some parameters of the optical system satisfy the following conditions:

f'>|f ₄ l > 0.8 f'

1.1 f'> f ₅ > 0.9 f ¹

0.9 f’ > f > 0.7 'f'

0.6 f ¹ ?|f ₇ l > 0.45 f', where:f' is the focal length f is the focal length of the entire optical system, f^ is the focal length of a biconcave lens £, f ₅ is the focal length of a biconvex lens £, fg is the focal length of a biconvex or plano lens £ and f? is the focal length of a biconcave lens Ί_.

The optical system of the high-speed lens according to the invention is technologically undemanding with a favorable ratio of diameters and radii for individual lenses, without the use of special types of optical glasses. At a relative aperture of 1:0.85, this optical system achieves a contrast of 0.8 for the center of the field of view and 0.4 for two-thirds of the field of view with a vignetting of less than 5%.

The structure of the optical system of the high-aperture lens is clear from the attached drawing.

Its first member, placed on the optical axis o, is a simple connecting meniscus £.

The second member is cemented from a biconvex lens £ and a biconcave lens'3.· Then follows a single-eared biconcave lens 4, a biconvex lens j>, a biconvex or planoconvex lens 6 and a biconcave lens 7. This is followed by a plane-parallel plate :8.

The following tables show the design parameters of two examples of optical systems according to the invention.

Example 1

R, = 59.99 X ^d i = . 11.50 1,622 87 60.0 ^R ? = 415,050 X from = 3.85 air R 57,280 3 d · = 18.30 1,622 87 60.0 ^R 4 = -100,925 From d. = 6.30 1,704 45 29.82 ^R with 152,070 3 0 ^huh ? = 5.85 air ^R fi = -89,950 From about ^d 4 = 4.10 1,723 11 29.82 ^R 7 with 63,960 ^e 8 = 9.15 air ^r r = 51,285 J 0 ^d 5 = 9.10 1,641 27 55.28 Rq = -111,680 y ^e 4 = 5.80 air ^R in = 32,209 and at ^d 6 = 10.75 1,661 51 50.57 ^R 11 = -446,650 About X X ^e 5 = 4.30 air R. y = -41,503 X of ^d 7 = 2.00 1,677 64 32.00 ^R n 5= 41,503 X X 2.00 air ^R 14 OO 6 days _ago 2.30 1,489 15 69.77 ^R 15 Both 8 f' = 58,513 n in ^R 1 = 59,690 e e X ^d l = 11.50 1,622 87 60.0 R, = 347.48 X from ^oh yeah 3.50 air R, 56,767 x 3 ^d 2 = 18.00 1,622 87 60.0 R, = -113,770 from ^d 3 = 6.00 1,704 45 29.82 R= = 135,872 3 0 ^e 9 from " 6.70 air ^R fi = -87,512 From 0 ^d 4 = 5.00 1,704 45 29.82 ^R 7 = 63,960 •i e-3 8.00 air ^R 8 = 51,515 About About ^d 5 = 9.60 1,622 87 60.0 Rq -105,660 y ^e u = 5.50 air ^R in = 29,380 X u d. = 10.30 1,641 27 55.28 ^R 11 WHAT 6 ^e 5 = 4.80 air R. y = -45,914 0 X Z ^d 7 2.00 1,671 58 32.85 R. = 38,920 X J ^e fi = 2.00 air ^R 14 = OO about ^dR time 2.30 1,489 15 69.77 ^R 15 = what 8

P = 58.236 where:

P is the focal length of the optical system,

R| to R^g are the radii of curvature of the individual lenses, to dg are the axial thicknesses of the individual lenses, to e^ are the air gaps between the individual optical elements, ηθ is the refractive index for the spectral line e and ^θ is the magnitude of the Abbe number.

In both examples of optical system designs, the design parameters of the radii of curvature, axial thicknesses of individual lenses, air gaps and refractive indices can be within tolerances of ±5%.

The optical system according to the invention is particularly suitable as part of a tandem arrangement of lenses for X-ray television technology.

Claims (5)

SUBJECT OF THE INVENTION 1. An optical system of a high-luminance objective, forming part of a tandem arrangement of objectives for X-ray television technology, where it is used as a secondary objective, following on from the primary collimating objective and mediating the image transmission from the side of the X-ray intensifier screen to the vidicon of the television camera, which is formed by six members, consisting of seven lenses, characterized in that the first member is formed by a connecting meniscus (1), the next member is a biconvex lens (2) cemented with a biconcave lens (3), then follows a biconcave lens (4), then a biconvex lens (5) and a biconvex or planoconvex lens (6) and a biconcave lens (7). 2. The optical system according to item 1, characterized in that its parameters have the following relationships: f' ><f ₄ > > 0.8 f' 1.1 f ’ > ^f 5 > 0.9 f' 0.9 f ’ > ^f 6 > 0.7 f' 0.6 f ’ > (f ₇ ) > 0.45 f where f’ f f is the focal length of the entire optical system, is the focal length of the biconcave lens (4), is the focal length of the biconvex lens (5), is the focal length of the biconvex or Planck lens (6) and is the focal length of the biconcave lens (7). '10 ^Λ 11 The optical system according to points 1 and 2, characterized in that it has the following parameters: n _rt In 59,999 415,050 57,280 100,925 152,070 -89,950 63,960 551,285 -111,680 32,209 -446,650 41,503 41,503 11.50 3.85 18.30 6.30 5.85 4.10 9.15 9.10 5.80 10.75 4.30 2.00 2.00 1,622 87 air 1,622 87 1,704 45 air 1,723 11 air 1,641 27 air 1,661 51 air 1,677 64 air 60.0 60.0 29.82 29.82 55.28 50.57 32.00 ^R 14 ^R 15 = 00 = 00 ^d 8 - 2.30 1,489 15 69.77 where: f' = 58,513, whereas ^R 1 ^{to R} 13 are radii curvature individual lenses, ^R 14' ^R 15 I am radii curvature planeparallel plates * d ₁ to dg are axial thicknesses of individual lenses and plane-parallel plates, ^e l ^{to e} 6 are air and the gaps between individual optical elements, no no is the refractive index for spectral line e and ^e is the size Abbe numbers, 4. Optical system according to points 1 and 2, characterized by* that has the following no no In ^R 1 = 59,690 ^d 1 11.50 1,622 87 60.0 R, = 347,480 1 £. ^e l = 3.50 air R, = 56,767 3 d 18.00 1,622 87 60.00 R, -113,770 from 4 d. = 6.00 1,704 45 29.82 R, = 135,872 3 3 ^θ 2 = 6.70 air ^r and -87,512 about ^d 4 = 5.00 1,704 H5 29.82 ^R 7 = 63,960 ‘i = 8.00 air ^R fi = 51,515 J about d. 9.60 1,622 87 60.00 ^Rq = -105,660 3 y ^e d = 5.50 air R _n n = 29,380 10 ^d 6 = 10.30 1,641 27 55.28 ^R 11 = ooo θΑ = 4.80 air ^R 1 0 = 45,914 3 12 ^d 7 = 2.00 1,671 58 32.85 ^R 1 Ί = 38,920 1 J ^e 6 2.00 air ^R 14 ooo ^d 8 = 2.30 1,489 15 69.77 ^R 15 = 00 where f' = 58,236, whereas ^R 1 ^{to R} 13 are radii curvature individual lenses, ^R 14' ^R 15 I am radii curvature plane-parallel plates, dj to άθ I am axial thicknesses of individual lenses and plane-parallel plates, e. to e, 1 6 I am air gaps between individual optical elements, no no is the refractive index for spectral line e and is the magnitude of the Abbe number