RU2531851C2 - Afocal attachment for tv cameras and photographic cameras - Google Patents

Abstract

FIELD: physics, photography.

SUBSTANCE: afocal attachment consists of the first component as a single positive lens (1) and the second component as a single negative lens (4). The first component has an afocal correctional component of the single magnification located between the positive (1) and negative (4) lenses and designed as series located concavo-convex negative meniscus (2) and convex-concave positive meniscuses (3) with equal focal powers touching to each other with convex surfaces. Focal distances of menisci (2) and (3) are equal to the focal distance of the positive lens (1) of the first component: $$-f_2^{\text{'}}=f_3^{\text{'}}=f_1^{\text{'}}$$

. The distance between the positive lens (1) and the point of contact of surfaces of menisci (2) and (3) is equal to half of the focal distance of the positive lens (1): $$d_{\mathrm{1,2}}=\frac{1}{2}{f}_1^{\text{'}}$$

, the distance between the menisci (2) and (3) is equal to: d_2,3=0. The focal distance of the negative lens (4) of the second components is equal to: $$f_4^{\text{'}}=\frac{-f_1^{\text{'}}}{"Г"},$$

and it is located from the point of contact of surfaces of menisci (2) and (3) at the distance: $$d_{\mathrm{3,4}}=\frac{f_1^{\text{'}}}{2\text{'}\text{'}Г\text{'}\text{'}}\left(\text{'}\text{'}Г\text{'}\text{'}-2\right),$$

where "Г" - magnification of afocal attachment.

EFFECT: increase of resolution of objects at the expense of increase of angular magnification.

4 dwg, 3 tbl

Г - "Г"

Description

Field of Invention

The invention relates to the field of optical instrumentation, namely to afocal nozzles designed to increase the focal length of the lenses of television cameras and cameras in order to ensure high spatial resolution during registration of objects.

State of the art

Known 4-lens afocal nozzle with an angular magnification of 1.5 times for the lenses of cameras with the internal position of the entrance pupil (patent US 4171872 A, 23.10.1979, G02B 13/22).

The afocal nozzle contains a positive two-lens bonded component and a negative two-lens bonded component. The disadvantage of this nozzle is the relatively small, not exceeding 1.5 times, angular increase. To achieve large values of increase, the mass of the first glued component, made in the form of gluing two lenses, increases sharply.

The 5-fold Galilean telescopic system is known for observing objects by humans (Carmen Menchaca and Daniel Malacara Design of Galilean-type telescope systems, APPLIED OPTICS / Vol.27, No.17 / 1 September 1988, pp.3715-3718). A significant limitation when using this system as an afocal lens for photo and television lenses is the small exit pupil diameter not exceeding 8 mm.

The closest in technical essence is a 3-lens afocal nozzle with an angular magnification of G = 1.71 times, designed for camcorder lenses (patent RU 2067309 C1, 09/27/2006, G02B 15/12; it is also adopted as a prototype).

This afocal nozzle with an angular magnification of 1.71 times contains two components, the first positive component made in the form of a single biconvex lens, and the second negative component consists of a positive meniscus facing a concave surface to the object and a single negative lens.

. Относительное отверстие афокальной насадки определяется отношением диаметра выходного зрачка D_ВЫХ.ЗР к фокусному расстоянию второго (отрицательного) компонента насадки $$f_2^{\text{'}}$$

и для прототипа составляет $$A=\frac{D_{ВЫХ.ЗР.}}{f_2^{\text{'}}}=1:4$$

.The angular field in the image space of the prototype 2W ′ = 7 °. The angular field in the space of objects is determined by the increase in the nozzle and is for the prototype $$2W=\frac{2W\text{'}\text{'}}{G}={4.1}^{\circ }$$

. The relative aperture of the afocal nozzle is determined by the ratio of the diameter of the exit pupil D _OUT.ZR to the focal length of the second (negative) component of the nozzle $$f_2^{\text{'}\text{'}}$$

and for the prototype is $$A=\frac{D_{\mathrm{AT}SX.3R.}}{f_2^{\text{'}\text{'}}}=\mathrm{one}:\mathrm{four}$$

.

при W=0° составляет 2ΔW=0,26 угл.мин; при W=1,1° $$2\Delta W=\frac{2\Delta W\text{'}}{Г}=\mathrm{3,5}угл.мин.$$

и при W=2,05° соответственно 11 угл.мин.In addition, this afocal nozzle is designed to operate in the spectral range of 486 ... 610 nm. At the same time, the nozzle has a high angular resolution in the center of the field of view of the image space — the angular size of the scattering spot is 2ΔW ′ = 26 angular sec. = 0.44 angular min, but low resolution over the image field: at W ′ = 1.8 ° angular the size of the scattering spot is 2ΔW = 6 arcmin, and at W ′ = 3.5 ° it is, respectively, 2ΔW ′ = 19 arc min. In the space of objects angular resolution $$2\Delta W=\frac{2\Delta W\text{'}\text{'}}{G}$$

at W = 0 ° it is 2ΔW = 0.26 arcmin; at W = 1,1 ° $$2\Delta W=\frac{2\Delta W\text{'}\text{'}}{G}=\mathrm{3,5}\mathrm{at}gl.m\mathrm{and}n.$$

and at W = 2.05 °, respectively, 11 arcmin.

Table 1 for the prototype for different angular fields presents the values of the angular dimensions of the spots of scattering in the space of images and in the space of objects.

Table 1 Nozzle 1.7 times Image space Object Space W ′, angle 2ΔW ′, arcmin

угл.град. $$W=\frac{W\text{'}\text{'}}{G}$$

angle $$2\Delta W=\frac{2\Delta W\text{'}\text{'}}{G}$$

, min 0 0.5 0 0.3 1.8 6 1,1 3,5 3,5 19 2.05 eleven

This nozzle has the following disadvantages: low resolution over the image field and, due to the small angular increase, low resolution in the space of objects, as well as a small relative aperture.

You can increase the resolution in the space of objects by increasing the angular increase. However, the correction capabilities of the prototype are limited to an increase of 1.71 times.

Disclosure of invention

To eliminate these shortcomings in the afocal nozzle, consisting of two components, in which the first component is positive and made in the form of a single positive lens (1), and the second component is negative and made in the form of a single negative lens (4), in addition to the first component a single-magnification afocal correction component is introduced, located on the optical axis between the positive lens (1) and the negative lens (4), and made in the form of sequentially located along the rays a concave-convex negative meniscus (2) and a convex-concave positive meniscus (3) with equal optical powers touching convex surfaces, the focal lengths of menisci (2) and (3) being equal to the focal length of the positive lens (1) of the first component :

; $$-f_2^{\text{'}\text{'}}=f_3^{\text{'}\text{'}}=f_{\mathrm{one}}^{\text{'}\text{'}}$$

;

the distance between the positive lens (1) of the first component and the point of contact of the surfaces of the menisci (2) and (3) of the afocal correction component is equal to half the focal length of the positive lens (1) of the first component:

$${\mathrm{<figure-callout\; id="1"\; label="d"\; filenames="00000035.png,00000036.png"\; state="\{\{state\}\}"><figure-callout\; id="2"\; label="d"\; filenames="00000034.png,00000035.png"\; state="\{\{state\}\}">d</figure-callout></figure-callout>}}_{\mathrm{1,2}}=\frac{\mathrm{one}}{2}{f}_{\mathrm{one}}^{\text{'}\text{'}}$$

meniscus distance:

d _2,3 = 0;

the focal length of the negative lens (4) of the second component is equal to:

, $$f_{\mathrm{four}}^{\text{'}\text{'}}=\frac{-f_{\mathrm{one}}^{\text{'}\text{'}}}{G}$$

,

and it is removed from the point of contact of the surfaces of the menisci (2) and (3) of the afocal correctional component at a distance:

$$\begin{array}{l}{d}_{3.4}=f_{\mathrm{one}}^{\text{'}\text{'}}-{\mathrm{<figure-callout\; id="1"\; label="d"\; filenames="00000035.png,00000036.png"\; state="\{\{state\}\}">d</figure-callout>}}_{\mathrm{1,2}}-f_{\mathrm{four}}\text{'}\text{'}=f_{\mathrm{one}}^{\text{'}\text{'}}-\frac{f_{\mathrm{one}}^{\text{'}\text{'}}}{2}-\frac{f_{\mathrm{one}}^{\text{'}\text{'}}}{G}=\\ =\frac{f_{\mathrm{one}}^{\text{'}\text{'}}}{2G}\left(G-2\right)\end{array}$$

where G is the increase in the afocal nozzle.

These formulas are obtained without taking into account the thickness of the lenses, i.e. for thin optical components. For components with real thicknesses, these formulas are approximate.

Brief Description of the Drawings

Figure 1 presents the optical diagram of the afocal nozzle with a 5-fold angular magnification in accordance with the present invention.

Figure 2 shows the energy distribution E (W) in the angular scattering spot in the space of objects ΔW for the axial beam of rays W = 0 °.

Figure 3 shows the energy distribution E (W) in the angular scattering spot in the space of objects ΔW for an off-axis beam of rays W = 0.36 °.

Figure 4 shows the energy distribution E (W) in the angular spot of scattering in the space of objects ΔW for an off-axis beam of rays W = 0.7 °.

As an example of the proposed afocal nozzle is a nozzle 5-fold increase.

Parameters of nozzle components with a magnification of 5 times, calculated by the formulas for thin optical components:

focal length of the nozzle 1, 2, 3, 4:

f ′ = ∞;

the focal length of the positive lens (1) of the first component:

; $$f_{\mathrm{one}}^{\text{'}\text{'}}=216.5mm$$

;

the distance between the positive lens (1) of the first component and the point of contact of the surfaces of the menisci (2) and (3) of the afocal correction component (2, 3):

; $${\mathrm{<figure-callout\; id="1"\; label="d"\; filenames="00000035.png,00000036.png"\; state="\{\{state\}\}"><figure-callout\; id="2"\; label="d"\; filenames="00000034.png,00000035.png"\; state="\{\{state\}\}">d</figure-callout></figure-callout>}}_{\mathrm{1,2}}=\frac{\mathrm{one}}{2}{f}_{\mathrm{one}}^{\text{'}\text{'}}=108.25mm$$

;

focal length of the negative meniscus (2) of the afocal correctional component (2, 3):

; $$f_2^{\text{'}\text{'}}=-f_{\mathrm{one}}^{\text{'}\text{'}}=-216.5mm$$

;

focal length of the positive meniscus (3) of the afocal correctional component (2, 3):

; $$f_3^{\text{'}\text{'}}=f_{\mathrm{one}}^{\text{'}\text{'}}=216.5mm$$

;

distance between menisci (2) and (3):

d _2,3 = 0;

focal length of the afocal correctional component (2, 3):

f ′ _2,3 = ∞;

the distance between the point of contact of the surfaces of the menisci (2) and (3) of the afocal correctional component and the negative lens (4) of the second component:

; $$d_{3.4}=\frac{f_{\mathrm{one}}^{\text{'}\text{'}}}{2G}=\left(G-2\right)=64.95mm$$

;

the focal length of the negative lens (4) of the second component is equal to:

. $$f_{\mathrm{four}}^{\text{'}\text{'}}=\frac{-f_{\mathrm{one}}^{\text{'}\text{'}}}{G}=43.3mm$$

.

Table 2 presents the design parameters of the proposed nozzle, the optical scheme of which is shown in figure 1.

table 2 Surface number Radius of curvature Thickness Glass Light diameter one 109,516 23 OK4 126.5 2 -786.57 78.64 126.4 3 -87,375 5 TF10 72.6 four -181,765 0 73.1 5 46.952 8 Bf7 68.7 6 69,842 69.22 67.3 7 -239,785 four KF6 25.05 8 24,205 40 22.15 Exit pupil plane 17.6

Parameters of nozzle components with real thicknesses of elements: focal length of nozzle (1), (2), (3), (4):

; $$f\text{'}\text{'}=8.6\cdot {10}^{5}mm$$

;

the focal length of the positive lens (1) of the first component:

; $$f_{\mathrm{one}}^{\text{'}\text{'}}=216.5mm$$

;

the distance between the positive lens of the first component (1) and the point of contact of the surfaces of the menisci (2) and (3) of the afocal correction component (2, 3):

d _1.2 = 102 mm;

focal length of the negative meniscus (2) of the afocal correctional component (2, 3):

; $$f_2^{\text{'}\text{'}}=-213.4mm$$

;

focal length of the positive meniscus (3) of the afocal correctional component (2, 3):

; $$f_3^{\text{'}\text{'}}=218.9mm$$

;

distance between menisci (2) and (3):

d _2,3 = 0;

focal length of the afocal correctional component (2, 3):

; $${\mathrm{<figure-callout\; id="2"\; label="f"\; filenames="00000034.png,00000035.png"\; state="\{\{state\}\}">f</figure-callout>}}_{\mathrm{2,3}}^{\text{'}\text{'}}=-5054mm$$

;

the distance between the point of contact of the surfaces of the menisci (2) and (3) of the afocal correctional component and the negative lens (4) of the second component:

d _3.4 = 77 mm;

the focal length of the negative lens (4) of the second component is

; $$f_{\mathrm{four}}^{\text{'}\text{'}}=-43.7mm$$

;

an increase in the afocal nozzle

G = 5 ^x .

As follows from the given parameters of the nozzle components, they are close to theoretical parameters.

Calculation of the afocal nozzle 5-fold increase was carried out for the same angular fields in the image space as the prototype, but with an increased relative aperture:

spectral range Δλ = 486 ... 610 nm;

angular field in the space of images - 2W ′ = 7 °;

.relative hole $$A=\frac{D_{\mathrm{AT}SX.3R.}}{f_{\mathrm{four}}^{\text{'}\text{'}}}=\mathrm{one}:2.5$$

.

.Moreover, due to the angular increase in the proposed nozzle G = 5 ^{x the} angular field in the space of objects is $$2W=\frac{2W\text{'}\text{'}}{G}={1.4}^{\circ }$$

.

Figure 2, 3 and 4 presents graphs of the energy distribution in the angular spot scattering nozzles in the space of objects for angular fields W = 0 °, W = 0.36 ° and W = 0.1 °. From these graphs it follows that according to the energy level E = 0.7 in the space of objects, the angular size of the scattering spot at W = 0 ° is 2ΔW = 0.06 arc.min. (in the space of images 2ΔW ′ = 0.3 arcmin), at W = 0.36 ° it is equal to 2ΔW = 0.36 arcmin (in the space of images 2ΔW ′ = 1.8 arc min) and W = 0, 7 ° is equal to 2ΔW = 3 arcmin (in the space of images 2ΔW ′ = 15 arc min).

для заданного углового поля $$W=\frac{W\text{'}}{Г}$$

.Table 3 shows the values of the angular size of the scattering spot of the proposed nozzle 2ΔW in the image space for a given angular field W ′ and in the space of objects $$2\Delta W=\frac{2\Delta W\text{'}\text{'}}{G}$$

for a given angular field $$W=\frac{W\text{'}\text{'}}{G}$$

.

Table 3 Nozzle 5 times Image space Object Space W ′, angle 2ΔW ′, arcmin

, угл.град. $$W=\frac{W\text{'}\text{'}}{G}$$

, angle $$2\Delta W=\frac{2\Delta W\text{'}\text{'}}{G}$$

, min 0 oh s 0 0.06 1.8 1.8 0.36 0.36 3,5 fifteen 0.7 3

From a comparison of tables 1 and 3, it follows that in the space of objects, the angular resolution of the proposed nozzle of 5-fold increase in the center of the field is increased 5 times, in the middle of the field - almost 10 times, and at the edge of the field - almost 4 times. In this case, the relative aperture is increased 1.6 times, which confirms the positive effect of the present invention.

Professionals in the art will understand that with this approach to the technical task that this solution provides, afocal nozzles can also be obtained with a different magnification, in addition to the above 5-fold magnification, considered by a specific example - i.e. with this approach to the constructive implementation of the afocal nozzle, the above choice of certain lenses, the above choice of their specific focal lengths, the above choice of certain distances between them, but by changing the increase in the G afocal nozzle to a different number of times.

The presence of features that distinguish the proposed nozzle from the prototype confirms the compliance of this proposal with the criterion of "novelty", namely, such a combination of all the features of the device, not known from the scientific, technical and patent literature, indicates compliance with the criterion of "inventive step".

Claims (1)

An afocal nozzle consisting of two components, in which the first component is positive and made in the form of a single positive lens (1), and the second component is negative and made in the form of a single negative lens (4), characterized in that the first component is additionally introduced afocal correction component of a single increase, located on the optical axis between the positive lens (1) and the negative lens (4) and made in the form of concave-convex sequentially arranged along the rays negative meniscus (2) and convex-concave positive meniscus (3) with equal optical powers touching convex surfaces, and the focal lengths of menisci (2) and (3) are equal to the focal length of the positive lens (1) of the first component:
$$-f_2^{\text{'}\text{'}}=f_3^{\text{'}\text{'}}=f_{\mathrm{one}}^{\text{'}\text{'}}$$

;
the distance between the positive lens (1) of the first component and the point of contact of the surfaces of the menisci (2) and (3) of the afocal correction component is equal to half the focal length of the positive lens (1) of the first component:
$$d_{\mathrm{1,2}}=\frac{\mathrm{one}}{2}{f}_{\mathrm{one}}^{\text{'}\text{'}}$$

,
the distance between menisci (2) and (3) is equal to:
d _2,3 = 0;
the focal length of the negative lens (4) of the second component is equal to:
$$f_{\mathrm{four}}^{\text{'}\text{'}}=\frac{-f_{\mathrm{one}}^{\text{'}\text{'}}}{G}$$

,
and it is removed from the point of contact of the surfaces of the menisci (2) and (3) of the afocal correctional component at a distance:
$$d_{3.4}=\frac{f_{\mathrm{one}}^{\text{'}\text{'}}}{2G}\left(G-2\right)$$

,
where G is the increase in the afocal nozzle.

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