A three-field compact infrared optical telescope system

Abstract

The application discloses a three-view-field compact infrared optical telescope system, and belongs to the technical field of aerial infrared detection and investigation. The system comprises a secondary mirror, a primary mirror, a first eyepiece, a second eyepiece and a third eyepiece, and is composed of a small-view-field optical mode, a middle-view-field optical mode and a large-view-field optical mode. The small-view-field optical mode is composed of the secondary mirror, the primary mirror, the first eyepiece, the second eyepiece and the third eyepiece. The middle-view-field optical mode is composed of a middle-view-field first objective lens, a middle-view-field second objective lens, the primary mirror, the first eyepiece, the second eyepiece and the third eyepiece. The large-view-field optical mode is composed of a large-view-field first objective lens, a large-view-field second objective lens, the primary mirror, the first eyepiece, the second eyepiece and the third eyepiece. The primary mirror, the first eyepiece, the second eyepiece and the third eyepiece are an optical fixed group, and the secondary mirror, the middle-view-field first objective lens, the middle-view-field second objective lens, the large-view-field first objective lens and the large-view-field second objective lens are switching groups. The three-view-field compact infrared optical telescope system can realize switching among the three optical view-field modes by replacing the switching groups. The application takes into account the application requirements of the infrared optical detection field, such as small-view-field tracking, middle-view-field identification and large-view-field scanning, and improves the integration rate of the system.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of aviation infrared detection and investigation technology, and particularly relates to a three-view-field compact infrared optical telescope system. BACKGROUND

[0002] The infrared detection system is a high-efficiency modern detection means, and has been widely popularized in military and civilian fields. Especially under the condition of severe natural environment and interference of other systems, it still has very strong detection ability and accurate positioning ability. For the field of aviation detection and investigation, it can work as a passive radar, mainly provides detection and tracking of targets appearing in the scene; has thermal imaging performance, and can be used for day and night scene navigation or visual judgment.

[0003] In order to improve the detection distance and target recognition ability of the infrared detection system, it needs to have multi-view-field detection ability, and provide different detection spatial resolutions. The large-view-field detection is used for platform scanning target discovery, the middle-view-field detection is used for target recognition, and the small-view-field detection is used for target tracking. The multi-view-field detection requirement increases the complexity of the optical system, increases the volume and weight of the infrared detection load, reduces the system performance, and increases the system development cost.

[0004] At present, the main technical approach of the infrared detection system composite waveband detection is: one is to adopt discrete aperture optical design, and to adopt physical superposition of multiple optical lenses. The advantage of this technical approach is simple design, and the disadvantage is large volume and weight cost, which reduces the system performance; another technical approach is to adopt common telescope optical design. The advantage of this technical approach is compact structure, light weight and low cost, and the disadvantage is large design difficulty. SUMMARY

[0005] The technical problem to be solved is:

[0006] In order to avoid the shortcomings of the prior art, the present application provides a three-view-field compact infrared optical telescope system with compact structure and light weight, which provides multiple detection resolutions under the condition of limited volume space of the detection load, adopts three-view-field infrared telescope design, considers the application requirements of the infrared optical detection field of small-view-field tracking, middle-view-field identification and large-view-field scanning, improves the integration rate of the system, and reduces the development cost.

[0007] The technical scheme of the present application is: a three-view field compact infrared optical telescope system, comprising a secondary mirror, a primary mirror, a first eyepiece, a second eyepiece, a third eyepiece, a middle field first objective lens, a middle field second objective lens, a large field first objective lens, and a large field second objective lens, wherein the secondary mirror, the primary mirror, the first eyepiece, the second eyepiece, and the third eyepiece form a small field optical mode, the middle field first objective lens, the middle field second objective lens, the primary mirror, the first eyepiece, the second eyepiece, and the third eyepiece form a middle field optical mode, and the large field first objective lens, the large field second objective lens, the primary mirror, the first eyepiece, the second eyepiece, and the third eyepiece form a large field optical mode.

[0008] The primary mirror, the first eyepiece, the second eyepiece, and the third eyepiece are an optical fixed group, and the secondary mirror, the middle field first objective lens, the middle field second objective lens, the large field first objective lens, and the large field second objective lens are switching groups, and the three optical field modes are switched by replacing different switching groups.

[0009] A further technical scheme of the present application is that in the small field optical mode, light rays pass through the primary mirror, the secondary mirror, the first eyepiece, the second eyepiece, and the third eyepiece in sequence, the center distance between the secondary mirror and the primary mirror is 100 mm, the secondary mirror is a non-spherical mirror, and the primary mirror is a two-surface mirror, both of which are made of aluminum or other optical materials.

[0010] A further technical scheme of the present application is that the optical system data of the small field optical mode are as follows:

[0011]

[0012] A further technical scheme of the present application is that in the middle field optical mode, light rays pass through the middle field first objective lens, the middle field second objective lens, pass through the middle hole of the primary mirror, and then pass through the first eyepiece, the second eyepiece, and the third eyepiece in sequence, the center distance between the middle field first objective lens and the middle field second objective lens is 45 mm, the middle field first objective lens is a convex lens made of monocrystalline germanium, and the middle field second objective lens is a concave lens made of zinc sulfide.

[0013] A further technical scheme of the present application is that the optical system data of the middle field optical mode are as follows:

[0014]

[0015] A further technical scheme of the present application is that in the large field optical mode, light rays pass through the large field first objective lens, the large field second objective lens, pass through the middle hole of the primary mirror, and then pass through the first eyepiece, the second eyepiece, and the third eyepiece in sequence, the center distance between the large field first objective lens and the large field second objective lens is 15.72 mm, the large field first objective lens is a convex lens made of zinc selenide, and the large field second objective lens is a concave lens made of zinc sulfide.

[0016] A further technical solution of the present application is that the optical system data of the large field of view optical mode are as follows:

[0017]

[0018]

[0019] A further technical solution of the present application is that the center intervals between the first eyepiece, the second eyepiece and the third eyepiece are 2.85 mm and 10.53 mm respectively; the first eyepiece is a concave lens, and the material is chalcogenide glass; the second eyepiece is a convex lens, and the material is zinc selenide; and the third eyepiece is a concave lens, and the material is barium fluoride.

[0020] A further technical solution of the present application is that the magnification of the small field of view mode is 5.1 times, and the infrared field of view angle is 4.6°; the magnification of the medium field of view mode is 3.43 times, and the infrared field of view angle is 6.9°; and the magnification of the large field of view mode is 2.45 times, and the infrared field of view is 9.6°.

[0021] A further technical solution of the present application is that the detection wave band of the optical telescopic system is a long-wave infrared 8-10 mu m wave band.

[0022] Beneficial effects

[0023] The present application has the advantages that the three-field compact infrared optical telescopic system has the advantages of three-field mode design, compact structure, light weight and the like, provides multiple detection resolutions, and meets the infrared optical detection requirements of small field of view tracking, medium field of view identification and large field of view scanning, and can be widely applied to the fields of military and civilian photoelectric detection and detection.

[0024] 1. The three-field telescopic system design is realized by only switching the objective lens group between the Cassegrain telescope secondary mirror and the secondary imaging telescope, and the switching mode is simple. The total length of the system is less than 300 mm, and the structure is compact.

[0025] 2. The system has three detection field of view modes, the small field of view magnification is 5.1 times, and the infrared field of view angle is 4.6°; the medium field of view optical magnification is 3.43 times, and the infrared optical field of view is 6.9°; and the large field of view magnification is 2.45 times, and the infrared optical field of view is 9.6°.

[0026] 3. The eyepiece group design adopts the material combination of low thermal optical coefficient of chalcogenide glass, zinc selenide and barium fluoride, and the optical power distribution scheme is concave lens, convex lens and concave lens, which can cope with three field changes. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 It is a structural schematic diagram of the three-field compact infrared optical telescopic system.

[0028] Figure 2 is the transfer function MTF diagram of the three-view field compact infrared optical telescope system of the present application.

[0029] Figure 3 is the diffraction spot diagram of the three-view field compact infrared optical telescope system of the present application.

[0030] BRIEF DESCRIPTION OF DRAWINGS 1. secondary mirror, 2. primary mirror, 3. first eyepiece, 4. second eyepiece, 5. third eyepiece, 6. middle view field first objective, 7. middle view field second objective, 8. large view field first objective, 9. large view field second objective. DETAILED DESCRIPTION

[0031] The embodiments described below with reference to the drawings are exemplary and are intended to explain the present application, and cannot be understood as a limitation of the present application.

[0032] In the description of the present application, it is understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise" and the like indicate the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the indicated device or element must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation of the present application.

[0033] As shown in Figure 1 , the specific parameters of the three-view field compact infrared optical telescope system of the present embodiment are as follows:

[0034] (I) Small view field system

[0035] Magnification: 5.1 times;

[0036] Infrared view field: 4.6°;

[0037] (II) Middle view field system

[0038] Magnification: 3.43 times;

[0039] Long-wave infrared view field: 6.9°;

[0040] (III) Large view field system

[0041] Magnification: 2.45 times;

[0042] Long-wave infrared view field: 9.6°;

[0043] (IV) Working waveband: 8-10 μm.

[0044] The three-field compact infrared optical telescope system comprises a secondary mirror 1, a primary mirror 2, a first eyepiece 3, a second eyepiece 4, a third eyepiece 5, a middle-field first objective lens 6, a middle-field second objective lens 7, a large-field first objective lens 8, and a large-field second objective lens 9, and constitutes three optical field detection modes of a small field, a middle field and a large field: the small field mode adopts a Cassegrain configuration; the middle field and the large field both adopt a secondary imaging configuration. In the small field optical mode, light rays pass through the primary mirror 2, the secondary mirror 1, the first eyepiece 3, the second eyepiece 4 and the third eyepiece 5 in sequence to form a small field optical telescope system; in the middle field optical mode, light rays pass through the middle-field first objective lens 6, the middle-field second objective lens 7, pass through the middle hole of the primary mirror 2, pass through the first eyepiece 3, the second eyepiece 4 and the third eyepiece 5 to form a middle field optical telescope system; in the large field optical mode, light rays pass through the large-field first objective lens 8, the large-field second objective lens 9, pass through the middle hole of the primary mirror 2, pass through the first eyepiece 3, the second eyepiece 4 and the third eyepiece 5 to form a large field optical telescope system.

[0045] Further, the primary mirror 2, the first eyepiece 3, the second eyepiece 4 and the third eyepiece 5 are an optical fixed group, which keeps the optical parameters unchanged and the position fixed during the field switching process.

[0046] Further preferably, the secondary mirror 1, the middle-field first objective lens 6, the middle-field second objective lens 7, the large-field first objective lens 8 and the large-field second objective lens 9 are switching groups, which are used for switching between the three optical field modes.

[0047] Further preferably, the switching groups and the fixed group have an equal interval during the field switching process.

[0048] Further preferably, the center distance between the secondary mirror 1 and the primary mirror 2 is 100 mm, the secondary mirror 1 is a non-spherical mirror, and the primary mirror 2 is a two-surface mirror, both of which are made of aluminum or other optical materials.

[0049] Further preferably, the center distance between the middle-field first objective lens 6 and the middle-field second objective lens 7 is 45 mm, the middle-field first objective lens 6 is a convex lens made of monocrystalline germanium, and the middle-field second objective lens 7 is a concave lens made of zinc sulfide.

[0050] Further preferably, the center distance between the large-field first objective lens 6 and the large-field second objective lens 7 is 15.72 mm, the first objective lens 6 is a convex lens made of zinc selenide, and the second objective lens 7 is a concave lens made of zinc sulfide.

[0051] Further preferably, the center distances between the first eyepiece 3, the second eyepiece 4 and the third eyepiece 5 are 2.85 mm and 10.53 mm, respectively, the first eyepiece 3 is a concave lens made of a sulfur glass, the second eyepiece 4 is a convex lens made of zinc selenide, and the third eyepiece 5 is a concave lens made of barium fluoride.

[0052] Embodiment:

[0053] The following is a preferred embodiment of the present application

[0054] A three-field compact infrared optical telescope system is made, which detects long-wave infrared band 8-10 μm and has three field modes. Among them, the small field has a magnification of 5.1 times and an infrared field of 4.6°; the medium field has a magnification of 3.43 times and an infrared field of 6.9°; the large field has a magnification of 2.45 times and an infrared field of 9.6°.

[0055] Table 1 is the small field telescope parameters of the 120mm aperture optical system. See Figure 1 The small field adopts a Cassegrain telescope configuration, the secondary mirror 1 is aspherical, the primary mirror 2 is parabolic, the first eyepiece 3, the second eyepiece 4 and the third eyepiece 5 are plano-concave, convex and concave lenses respectively, and the materials are IRG24, zinc selenide and barium fluoride respectively.

[0056] Table 1:

[0057]

[0058] Table 2 is the medium field telescope parameters of the 80mm aperture optical system. See Figure 1 The medium field adopts a transmissive telescope configuration. The objective group includes the medium field first objective 6 and the medium field second objective 7, which are switched with the small field secondary mirror 1 for field switching. The first eyepiece 3, the second eyepiece 4 and the third eyepiece 5 are concave, convex and concave lenses respectively, and the materials are IRG24, zinc selenide and barium fluoride respectively.

[0059] Table 2:

[0060]

[0061]

[0062] Table 3 is the large field telescope parameters of the 57mm aperture optical system. See Figure 1 The large field adopts a transmissive telescope configuration. The objective group includes the large field first objective 8 and the large field second objective 9, which are switched with the small field secondary mirror 1 for field switching. The first eyepiece 3, the second eyepiece 4 and the third eyepiece 5 are fixed groups, and the parameters are consistent with those of the small field.

[0063] Table 3:

[0064]

[0065] Figure 2This is the MTF plot of a compact infrared optical telescope system with three fields of view. Figure 2 As shown, at 20 cycles / mm, the MTF of each field of view is greater than 0.4, approaching the diffraction limit. This ensures that the lens telescope can obtain high-resolution infrared image information.

[0066] Figure 3 This is a dot diagram of a compact, three-field-of-view infrared optical telescope system. (Example:) Figure 3 As shown, the blur spots in each field of view are all less than 12 μm, which is smaller than the pixel size of the long-wave infrared detector. This ensures image resolution and detection energy convergence, thus guaranteeing the target detection range.

[0067] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention without departing from the principles and spirit of the present invention.

Claims

1. A three field-of-view compact infrared optical telescopic system, characterized in that: The optical system comprises a secondary mirror, a primary mirror, a first eyepiece, a second eyepiece, a third eyepiece, a medium field first objective lens, a medium field second objective lens, a large field first objective lens and a large field second objective lens; the small field optical mode is formed by the secondary mirror, the primary mirror, the first eyepiece, the second eyepiece and the third eyepiece; the medium field optical mode is formed by the medium field first objective lens, the medium field second objective lens, the primary mirror, the first eyepiece, the second eyepiece and the third eyepiece; and the large field optical mode is formed by the large field first objective lens, the large field second objective lens, the primary mirror, the first eyepiece, the second eyepiece and the third eyepiece; The primary mirror, the first eyepiece, the second eyepiece and the third eyepiece are an optical fixed group, and the secondary mirror, the medium field first objective lens, the medium field second objective lens, the large field first objective lens and the large field second objective lens are switching groups; the switching between the three optical field modes is realized by replacing the switching groups; In the small field optical mode, light passes through the primary mirror, the secondary mirror, the first eyepiece, the second eyepiece and the third eyepiece in sequence; the center distance between the secondary mirror and the primary mirror is 100 mm; the secondary mirror is a non-spherical mirror; and the primary mirror is a second curved mirror, both of which are made of aluminum or other optical materials; In the medium field optical mode, light passes through the medium field first objective lens, the medium field second objective lens, the primary mirror, the first eyepiece, the second eyepiece and the third eyepiece in sequence; the center distance between the medium field first objective lens and the medium field second objective lens is 45 mm; the medium field first objective lens is a convex lens made of monocrystalline germanium; and the medium field second objective lens is a concave lens made of zinc sulfide; In the large field optical mode, light passes through the large field first objective lens, the large field second objective lens, the primary mirror, the first eyepiece, the second eyepiece and the third eyepiece in sequence; the center distance between the large field first objective lens and the large field second objective lens is 15.72 mm; the large field first objective lens is a convex lens made of zinc selenide; and the large field second objective lens is a concave lens made of zinc sulfide; The center distances between the first eyepiece, the second eyepiece and the third eyepiece are 2.85 mm and 10.53 mm respectively; the first eyepiece is a concave lens made of sulfur glass; the second eyepiece is a convex lens made of zinc selenide; and the third eyepiece is a concave lens made of barium fluoride.

2. The compact infrared optical telescope system of claim 1, wherein: The optical system data of the small field optical mode are as follows: 。 3. The compact infrared optical zoom system of claim 1, wherein: The optical system data of the medium field optical mode are as follows: 。 4. The compact infrared optical zoom system of claim 1, wherein: The optical system data of the large field optical mode are as follows: 。 5. The compact infrared optical zoom system of any of claims 1-4, wherein: The magnification of the small field mode is 5.1 times, and the infrared field of view is 4.6°; the magnification of the medium field mode is 3.43 times, and the infrared field of view is 6.9°; and the magnification of the large field mode is 2.45 times, and the infrared field of view is 9.6°.

6. The compact infrared optical zoom system of claim 5, wherein: The detection wave band of the optical telescopic system is the long-wave infrared 8 μm-10 μm wave band.

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