KR101314516B1 - Imaging lens system for day and night sight - Google Patents

Abstract

PURPOSE: An imaging lens system for combined day and night sight obtains clear images in a wide range from visible to near-infrared bands while having a large angle of view and bright brightness. CONSTITUTION: An imaging lens system (1000) for combined day and night sight includes an object lens system (100), a reticle lens (200), and a relay lens system (300) in order from an object side. The object lens system includes a first lens group (10) and a second lens group (20) in order from the object side. The first lens group is formed in a structure having positive refraction power. The second lens group has the positive refraction power and is formed in the form of a convex meniscus. The reticle lens is formed in the form of a flat surface with a reticle pattern. The relay lens system includes a fourth lens group (40) and a fifth lens group (50). The fourth lens group is formed in the structure having the positive refraction power. The fifth lens group has negative refraction power in the form of the convex meniscus to the object side and is formed in the structure of a symmetric Gaussian lens system. [Reference numerals] (AA) Nighttime optical portion; (BB) Daytime optical portion

Description

Imaging lens system for day and night sighting {Imaging lens system for day and night sight}

The present invention relates to an imaging lens system for a collimator, and more particularly, to an imaging lens system for a day / night combined scope.

Daytime optical equipment is an optical equipment that uses abundant daylight, and is relatively easy to manufacture by simply consisting of optical elements such as glass or plastic and light fixtures, and general binoculars, telescopes, and sight glasses.

On the other hand, nighttime optical equipment, unlike daytime optical equipment that uses visible light during the day, uses a stray light amplification method or a thermal imaging method for detecting infrared rays (heat) to check an image even in a dark environment at night. In particular, the stray light amplification type optical equipment forms an image converted into a bright image by using the photoelectric effect, electron number amplification, all-optical effect, etc. It is a device for aiming and has been made in various forms such as binocular telescopes and sights. However, stray light-amplified optical equipment cannot be used during the day because the equipment is damaged during the day when the light intensity is high. Therefore, if you need to use the optical equipment consecutively during the day and at night, carry the day and night optical equipment separately. There has been inconvenience.

Therefore, in order to overcome this problem, various types of day and night combined equipment have been developed. For example, in the case of the day and night scope, the objective lens is used in common, and the relay unit or the eyepiece unit is replaced, or the lens system is composed of two paths, day and night, and the light path is switched by the shutter. In the case of replacing the conventional relay or eyepiece, the field of view of the imaging optical system is small and dark. When the aperture of the objective lens system is designed to be 50 mm or more, light of the outer angle occurs and the resolution is difficult, which makes it difficult to identify the remote object and the night. There was a problem in that the performance in the night mode is significantly lower than the single sight scope. The light path switching method can be easily changed from day mode to night mode, but it is difficult to change quickly, and it is inconvenient because it is large and heavy because it uses two lens parts from the relay part to the eyepiece part.

Moreover, in the case of nighttime optical equipment, the spectral band of the illumination light due to the background scattering of the sky at night observation ranges from the blue wavelength to the near infrared region, and its luminescence intensity increases continuously in the long wavelength direction. Since the photocathode response spectrum band is approximately 500 nm to 900 nm, the chromatic aberration of the imaging lens system also needs to be corrected in the wide wavelength band from the visible to the near infrared region.

Accordingly, an object of the present invention is to provide an imaging lens system commonly used for both day and night scopes that can solve the above problems, and provides a bright imaging lens system having a large viewing angle (10 degrees or more) and a small number of fs (f number 1.5 or less). It is.

It is another object of the present invention to provide a day and night imaging lens system that can correct chromatic aberration and other aberrations for a wide wavelength band from visible to near infrared, and can provide appropriate resolution according to the characteristics of the image amplification tube used. will be.

In order to achieve these and other objects, the imaging optical system for day and night scope according to one feature of the present invention is composed of an objective lens system, a mesh lens, and a relay lens system in order from the object side.

The objective lens system is in order from an object side,

A first lens group having an overall positive refractive power;

It consists of a second lens group having a positive refractive power as a whole in the form of a meniscus convex toward the object side,

The mesh lens is a planar lens in which a mesh pattern is engraved.

Relay lens system

A fourth lens group having overall positive refractive power;

A fifth lens group having a generally negative refractive power in the form of a meniscus convex toward the object side and having a Gaussian symmetric lens system structure;

A sixth lens group having a generally positive refractive power in a meniscus shape concave toward the object side and having a Gaussian symmetric lens system structure; And

It consists of a seventh lens group having a positive refractive power as a whole in the form of a meniscus convex toward the object side.

At this time, each lens group satisfies the following equation.

-1.50 ≤ F1 / f ≤ -1.90,

-1.50 ≤ F2 / f ≤ -1.90,

-0.20 ≤ F4 / f ≤ -0.30,

0.25 ≤ F5 / f ≤ 0.30,

-0.20 ≤ F6 / f ≤ -0.25,

-0.50 ≤ F7 / f ≤ -0.60

Where f is the effective focal length of the entire objective lens system,

F1, F2, F4, F5, F6, and F7 are effective focal lengths of the first to seventh lens groups, respectively.

The first lens group preferably comprises a meniscus triple lens convex toward the object side, including a convex first lens, a biconcave second lens, and a convex meniscus third lens.

It is preferable that a 2nd lens group consists of the 4th lens of the convex form on the object side, and the 5th lens of the biconcave form.

The mesh lens is formed by joining a sixth lens and a seventh lens of a planar shape, and a mesh pattern is engraved on the bonding surface between the sixth and seventh lenses, and the mesh pattern is formed on the focal plane of the objective lens system. .

The fourth lens group preferably comprises an eighth lens of meniscus shape concave toward the object side and a ninth biconvex lens.

The fifth lens group preferably includes a tenth lens of convex shape, an eleventh lens of cationic form, and a twelfth lens of cationic form.

The sixth lens group preferably includes the thirteenth lens of the meniscus shape concave toward the object side, and the fourteenth and fifteenth lenses of the double-fold lens type with an air layer.

The seventh lens group preferably includes a sixteenth lens having a convex meniscus shape and a seventeenth lens having a concave shape.

Day and night scope imaging lens system according to the present invention is applied to the method of using the day and night eyepiece replacement is possible to obtain a clear image in a wide band from the visible light to the near infrared band with a large angle of view and bright brightness. In other words, combining day and night eyepieces with the imaging lens system provides the functions of daytime and nighttime sights, provides a wide viewing angle over a wide range of wavelengths, reduces aberrations that can affect performance, and reduces low F and high You can get bright and clear images with MTF values.

1 is a view showing an optical unit including an imaging lens system of day and night scope according to an embodiment of the present invention,
2 is a view showing an imaging lens system of day and night scope according to the present invention,
3 is a graph illustrating a modulation transfer function (MTF) of an imaging lens system according to an exemplary embodiment of the present invention.

DETAILED DESCRIPTION Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 shows an optical part of the day and night sight, and the optical part of the day and night sight can be used as daytime optics and night vision by replacing the eyepiece system used. That is, the optical unit of the day and night collimator consists of an imaging lens system 1000 and an eyepiece system 2000, and the imaging lens system 1000 includes an objective lens system 100, a reticulated lens 200, and a relay lens system 300. The daytime optics are used by combining the daytime eyepiece system 400 to the imaging lens system 1000, and the nighttime optics are used by combining the image amplification tube 500 and the nighttime eyepiece system 600 to the imaging lens system 1000.

1 and 2, an imaging lens system 1000 according to the present invention will be described. The objective lens system 100 of the imaging lens system 100 according to the present invention includes two lens groups, and the reticle lens 200 includes one lens group, and the relay lens system 300 includes four lens groups.

First, the objective lens system 100 is composed of a first lens group 10 and a second lens group 20, the first lens group 10 of the convex lens, concave lens and convex meniscus convex toward the object side. It consists of a first lens 1, a second lens 2, a third lens 3 in the form of a triple lens form and has a positive refractive power as a whole. The first lens 3 to the third lens 3 are formed in close proximity. The second lens 2 is made of a high refractive index, high dispersion glass material having a refractive index of 1.8 or more and a dispersion coefficient of 25.5 or less, and the third lens 3 is made of a low refractive index or low dispersion glass material of a refractive index of 1.55 or less, a dispersion coefficient of 55.5 or more. Preferably, low refractive crown glass having a refractive index of about 1.5 can be used.

At this time, the effective focal length F1 of the first lens group 10 satisfies the following equation.

-1.50 ≤ F1 / f ≤ -1.90,

Where f is the effective focal length of the entire objective lens system.

The second lens group 20 has a positive refractive power as a whole in the form of a meniscus convex toward the object side. The second lens group 20 is composed of a convex fourth lens 4 and a fifth lens 5 in the form of a concave, and has a form in which a meniscus lens convex toward the object side is separated. At this time, the fourth lens 4 convex toward the object side reduces the length of the lens system and the fifth lens 5 which is the concave lens serves to straighten the image surface curvature. The fifth lens 5 is preferably made of a high refractive index, high dispersion glass material having a refractive index of 1.8 or more and a dispersion coefficient of 25.5 or less. In the case of forming an imaging lens system with a slightly lower resolution, the second lens group may be composed of one meniscus convex toward the object side.

At this time, the effective focal length F2 of the second lens group 20 satisfies the following equation.

-1.50 ≤ F2 / f ≤ -1.90,

The mesh lens 200 is formed of a third lens group 30, and the third lens group 30 is formed by bonding a sixth lens 6 and a seventh lens 7 having a planar shape in which a mesh pattern is engraved. An elaborate mesh pattern is formed on the surface where the sixth lens 6 is bonded to the seventh lens 7, and the mesh pattern is positioned on the first focal plane which is the focal position of the objective lens system 100.

In this case, the sixth lens 6 is made of a low refractive index, low dispersion glass material having a refractive index of 1.55 or less and a dispersion coefficient of 55.55 or more, and is preferably manufactured using a soft material (C12, BK7, etc.) so as to easily etch a wire pattern. The seventh lens 7 uses a high refractive index and high dispersion glass material having a refractive index of 1.8 or more and a dispersion coefficient of 25.5 or less to prevent the light from spreading.

Since the mesh pattern is formed on the joint surface of the sixth lens 6 and the seventh lens 7, no dust or foreign matter penetrates into the focal plane, and thus a clean image free of foreign matter or dust can be obtained even when the scope is used for a long time. have. In addition, the engraved reticulated pattern is engraved with white paint, and then illuminated with various light sources such as LEDs, LDs or other radioactive light emitting materials from the lens outer diameter to obtain a vivid and vivid net pattern without light scattering or bleeding. Thus, aiming at a dark environment or a black object becomes very easy.

The relay lens system 300 is composed of the fourth lens group 40 to the seventh lens group 70, and serves to reverse the external image and transfer the mesh pattern image to the second focal plane. At this time, the image formed on the second focal plane by the relay lens system 300 has aberration corrected and there is no image curvature or distortion. The image formed at the second focal position is connected at the focal plane of the image amplification tube 500 and the night eyepiece system 600 of the night optical unit to form a night image, or is connected to the daytime eyepiece system 400 and the focal plane at daytime. Make a video. Therefore, it is possible to obtain a clear and clear image day and night by replacing and connecting the eyepiece system. The magnification of the relay lens system 300 is 1 times, and the image diameter is designed in consideration of the specification of the image amplification tube 500, and is generally 18 mm.

The fourth lens group 40 is composed of an eighth lens, a meniscus lens concave toward the object side, and a biconvex ninth lens, and serves as a field lens to prevent spreading the light beam that passes through the objective lens system focus inwardly. do. The fourth lens group 40 may be configured in one piece as long as the spread of light rays is small without affecting resolution or other aberrations.

At this time, the effective focal length F4 of the fourth lens group 40 satisfies the following equation.

-0.20 ≤ F4 / f ≤ -0.30,

The fifth lens group 50 is a Gaussian symmetrical lens system structure, and includes a tenth lens 10, an eleventh lens 11, and a twelfth lens 12 in the form of convex, amphipathic, and biconcave convex toward the object. It has negative refractive power in the form of meniscus. The twelfth lens 12 is preferably made of a high refractive index, high dispersion glass material having a refractive index of 1.8 or more and a dispersion coefficient of 25.5 or less.

At this time, the Gaussian symmetry lens may be appropriately divided into several lenses according to the viewing angle and required resolution of the imaging optical system. If the lens system having a magnification of about 4 degrees with a viewing angle of 10 degrees, it is necessary to separate it into three to four sheets to obtain the required performance.

At this time, the effective focal length F5 of the fifth lens group 50 satisfies the following equation.

0.25 ≤ F5 / f ≤ 0.30,

The sixth lens group 60 is a Gaussian symmetric lens system structure and includes a thirteenth lens of a meniscus shape concave toward the object side and a meniscus shape concave toward the object side, and an air layer in the form of a typical achromatic lens. 14 and fifteenth lenses, and have a positive refractive power as a whole. In this case, the 14th and 15th lenses use print glass and crown glass.

At this time, the effective focal length F6 of the sixth lens group 60 satisfies the following equation.

-0.20 ≤ F6 / f ≤ -0.25,

The seventh lens group 70 includes a sixteenth lens 16 convex in the form of a meniscus convex toward the object side and a seventeenth lens 17 in the form of a concave, and has a positive refractive power, and separates the convex meniscus lens. If a somewhat lower resolution is required in the form, it may be composed of one convex meniscus. The seventeenth lens 17 is preferably made of a low refractive index, low dispersion glass material having a refractive index of 1.55 or less and a dispersion coefficient of 55.5 or more.

At this time, the effective focal length F7 of the seventh lens group 70 satisfies the following equation.

-0.50 ≤ F7 / f ≤ -0.60

In addition, in consideration of the thickness of the protective glass window 510 of the image amplifying tube 500 in the seventh lens group 70, it should be designed to have a long post focal length of 10 mm or more.

Examples according to the present invention are shown in Table 1 below.

if Radius of curvature (mm) Thickness or spacing (dn) (mm) Effective diameter (mm) Refractive index Dispersion coefficient r1 101.8 9.7 65 1.68 55.5 r2 -498.7 2.8 65 r3 -211.6 3.3 63 1.85 23.8 r4 322.2 0.5 63 r5 84.5 7.6 61 1.52 64.2 r6 302.3 85 61 r7 32.5 7 36 1.68 55.5 r8 ∞ 9 36 r9 -87.7 2.8 24 1.81 25.5 r10 67.5 17 24 r11 ∞ 2 20 1.52 58.6 r12 ∞ 6 20 1.85 23.8 r13 ∞ 10 20 r14 -20.4 7 22 1.65 58.4 r15 -16.6 5.5 25 r16 93.5 6 25 1.65 58.4 r17 -33.5 One 24 r18 24.0 5 22 1.65 58.4 r19 -189.9 2 22 r20 -31.1 2 20 1.69 31.2 r21 126.9 3.3 20 r22 -17.5 3 20 1.81 25.5 r23 131.4 3.3 20 r24 -92.6 5 22 1.64 60.2 r25 -17.3 2.6 22 r26 86.8 2 22 1.69 31.2 r27 19.9 One 2 r28 21.7 5 22 1.65 58.4 r29 -64.8 5.8 22 r30 17.5 6 22 1.65 58.4 r31 -153.8 7.4 22 r32 -17.3 2 20 1.52 59.0 r33 45.0 9.9 20 r34 ∞ 18

In this embodiment, the effective focal length of the entire imaging lens system is 100 mm, the main wavelength which is the basis for all analysis and numerical calculation is 700 nm, and the aberration can be corrected to the region of 550 to 850 nm. In addition, the focal plane of the imaging lens system of Table 1 becomes the rear surface of the protective glass window 510 of the image amplifier tube 500.

In addition, when the imaging lens system of the present invention is used together with the image amplification tube 500 having a diameter of 18 mm, the viewing angle is about ± 5 °, so that the viewing lens has a wide viewing angle as an aiming mirror, and the F number has a brightness of 1.5 or less.

Furthermore, the imaging lens system of the present invention was designed to be 34 lp / mm in consideration of the resolution arc angle of the human eye for 1 minute. 3 is a graph of a modulation transfer function (MTF) of the imaging lens system according to the present embodiment. In the graph, the vertical axis represents the standardized modulation transfer function value, and the horizontal axis represents the resolution (lp / mm). (A) to (c) in FIG. 3 indicate when the viewing angles are 0 °, ± 2.5 °, and ± 5 °, respectively, T is the meridional direction resolution, S is the nodular surface direction resolution, and the curve indicated by the dotted line is The diffraction limit is shown.

As described above, when combined with the day and night eyepieces combined day and night vision lens system according to the present invention provides a function as a day and night scope. In addition, it provides a wide viewing angle over a wide wavelength band, reduces aberrations that can affect performance, and obtains bright and clear images with low F and high MTF values.

Although the technical features of the present invention have been described above with reference to specific embodiments, those skilled in the art to which the present invention pertains can make various changes and modifications within the scope of the technical idea according to the present invention. It is obvious.

1000: imaging lens system
2000: eyepiece system
100: objective lens system
200: mesh lens
300: relay lens system
400: daytime eyepiece system
500: video amplifier
600: night eyepiece system
10-70: 1st lens group-7th lens group

Claims (15)

An imaging lens system for both day and night vision, comprising an objective lens system, a reticulated lens, and a relay lens system in order from an object side,
The objective lens system is in order from the object side,
A first lens group having an overall positive refractive power;
Second lens group having a generally positive refractive power in the form of a meniscus convex toward the object side
/ RTI >
The mesh lens is a flat lens engraved with a mesh pattern,
The relay lens system
A fourth lens group having overall positive refractive power;
A fifth lens group having a generally negative refractive power in the form of a meniscus convex toward the object side and having a Gaussian symmetric lens system structure;
A sixth lens group having a generally positive refractive power in a meniscus shape concave toward the object side and having a Gaussian symmetric lens system structure; And
Seventh lens group having positive refractive power as a whole in the form of meniscus convex toward the object side
/ RTI >
Each lens group is
-1.50 ≤ F1 / f ≤ -1.90,
-1.50 ≤ F2 / f ≤ -1.90,
-0.20 ≤ F4 / f ≤ -0.30,
0.25 ≤ F5 / f ≤ 0.30,
-0.20 ≤ F6 / f ≤ -0.25,
-0.50 ≤ F7 / f ≤ -0.60
(Where f is the effective focal length of the entire objective lens system,
F1, F2, F4, F5, F6, and F7 represent effective focal lengths of the first to seventh lens groups, respectively.)
Day and night aiming imaging system. The method of claim 1,
The first lens group includes a first lens having a convex shape, a second lens having a concave shape, and a third lens having a convex meniscus shape. Imaging lens system for day and night sighting. The method of claim 1,
The second lens group is a day and night imaging lens system characterized in that it comprises a fourth lens of the convex shape toward the object side and a fifth lens of the biconcave shape. The method of claim 1,
The mesh lens is formed by bonding a sixth lens and a seventh lens of a planar shape, and a mesh pattern for day and night scopes, characterized in that the mesh pattern is engraved on the bonding surface between the sixth lens and the seventh lens. The method of claim 1,
The imaging lens system for day and night scopes, characterized in that the mesh pattern of the mesh lens is formed on the focal plane of the objective lens system. The method of claim 1,
The fourth lens group includes an eighth lens having a meniscus shape concave toward the object side, and a biconvex ninth lens. The method of claim 1,
The fifth lens group includes a convex shape tenth lens, an elliptical shape eleventh lens, and a diorama shaped twelfth lens. The method of claim 1,
And said sixth lens group comprises a thirteenth lens of a meniscus shape concave toward the object side, and a fourteenth and fifteenth lenses of a double-fold lens type with an air layer. The method of claim 1, wherein
The seventh lens group includes a sixteenth lens having a meniscus shape convex toward the object side, and a seventeenth lens having a concave shape. The method according to any one of claims 2, 3, 4, and 7,
At least one of the second lens, the fifth lens, the seventh lens, and the twelfth lens is formed of a glass material having a refractive index of 1.8 or more and a dispersion coefficient of 25.5 or less. The method according to any one of claims 2 and 4, wherein
At least one of the third lens, the sixth lens, and the seventeenth lens is formed of a glass material having a refractive index of 1.55 or less and a dispersion coefficient of 55.5 or more. 5. The method of claim 4,
The sixth lens is a glass material having a refractive index of 1.55 or less and a dispersion coefficient of 55.5 or more.
The seventh lens is an imaging lens system for day and night scopes, characterized in that made of a glass material having a refractive index of 1.8 or more, dispersion coefficient of 25.5 or less. 10. The method according to any one of claims 1 to 9,
At least one of the lenses constituting the fifth lens group and the sixth lens group is an achromatic lens (achromatic lens), day and night imaging lens system. 10. The method according to any one of claims 1 to 9,
Combined lens system for day and night vision, characterized in that to use the imaging lens system for daytime sighting by combining the daytime eyepiece system or to combine the nighttime eyepiece system. 10. The method according to any one of claims 1 to 9,
When using as a night vision sighting, day and night aiming imaging system, characterized in that the image amplification tube is coupled between the imaging lens system and the eyepiece system.

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