Large-view-field infrared lens

Abstract

The invention provides a large-view-field infrared lens. The large-view-field infrared lens comprises a lens body, two front fixing sets arranged above the lens body, a fast reflecting mirror set arranged in the lens body and a relay set arranged on the right side of the lens body. The relay group is horizontally arranged, the included angle between the fast reflecting mirror group and the horizontal direction is 45 degrees, the two front fixing groups are inclined by 20 degrees relative to the vertical direction, and the included angle between the two front fixing groups is 40 degrees; according to the large-view-field infrared lens, a 1280 * 1024-at10 [mu] m medium-wave refrigeration type detector is used, the view field angle is larger than or equal to 84.5 degrees * 54.2 degrees, and the imaging performance is good; the F number of the optical system is 2.0, the light flux of the system is increased, and the sensitivity is improved; distortion is less than or equal to 1.0%; the lens is small in size and compact in structure, and the adjustment precision of the lens is improved; the optical athermalization design is adopted to eliminate thermal difference and chromatic aberration, and athermalization is achieved within the temperature range from-40 DEG C to 70 DEG C.

Description

Technical Field

[0001] The invention belongs to the technical field of infrared lenses, and in particular relates to an infrared lens with a large field of view. Background Art

[0002] In recent years, infrared thermal imaging systems have been widely used in military and security fields, and related technologies have developed rapidly. Due to the high detection and recognition rate of medium-wave infrared thermal imagers for characteristic targets, they can achieve all-weather real-time alert, and the demand for equipment in border defense, customs, airports and other places is increasing.

[0003] The search, detection and identification of characteristic targets require a large field of view, long focal length and large clear aperture. Generally, multiple thermal imagers are stitched together or multi-field thermal imagers are used, with long focal length identification and short focal length search and detection. These two methods are relatively large in size and weight, which is not conducive to modular integration. This patent designs a large-field-of-view infrared lens that quickly switches the left and right optical paths through a fast-reflection mirror group and uses a back-end processor for image stitching, which not only meets the requirements of a large field of view, long focal length and large clear aperture, but also reduces the structural size and weight. Summary of the invention

[0004] The purpose of the present invention is to design a large field of view infrared lens, adopt a secondary imaging system, achieve 100% cold aperture matching, reduce system stray light, effectively reduce volume and weight, design and control distortion, and improve the accurate output of detecting target position.

[0005] To this end, the wide-field-of-view infrared lens provided by the present invention comprises a lens body, two front fixed groups arranged above the lens body, a quick reflex mirror group arranged inside the lens body, and a relay group arranged on the right side of the lens body; the relay group is arranged horizontally, the quick reflex mirror group is at an angle of 45° to the horizontal direction, the two front fixed groups are arranged at an inclination of 20° relative to the vertical direction, and the angle between the two front fixed groups is 40°.

[0006] Furthermore, the fast-reflection mirror group drives the reflector to adjust its angle by rotating the motor, and the adjustment angle range of the fast-reflection mirror group is -10° to 10°.

[0008] Furthermore, the front fixed group includes a first lens group, a second lens group, a third lens group, and a seventh pressure ring. The first lens group includes a first lens, a first frame, and a first pressure ring. The first lens is arranged in the first frame, and the first pressure ring is arranged above the first lens; the second lens group includes a second lens, a second frame, and a second pressure ring. The second lens is arranged in the second frame, and the second pressure ring is arranged above the second lens; the third lens group includes a third lens, a third frame, and a third pressure ring. The third lens is arranged in the third frame, and the third pressure ring is arranged above the third lens.

[0009] Further, the relay group includes a fourth lens group, a fifth lens group, a sixth lens group, and an eighth pressure ring. The fourth lens group includes a fourth lens, a fourth lens frame, and a fourth pressure ring. The fourth lens is arranged in the fourth lens frame, and the fourth pressure ring is arranged above the fourth lens; the fifth lens group includes a fifth lens, a fifth lens frame, and a fifth pressure ring. The fifth lens is arranged in the fifth lens frame, and the fifth pressure ring is arranged above the fifth lens; the sixth lens group includes a sixth lens, a sixth lens frame, and a sixth pressure ring. The sixth lens is arranged in the sixth lens frame, and the sixth pressure ring is arranged above the sixth lens.

[0010] Furthermore, the right side of the relay group corresponds to the detector window, and a detector cold stop is arranged on the right side of the detector window.

[0011] The invention provides such a large-viewing-field infrared lens, which uses a 1280*1024@10μm medium-wave cooling detector, has a viewing angle of ≥84.5°x54.2°, and has good imaging performance under the required 50lp / mm; the F number of the optical system is 2.0, which increases the light throughput of the system and improves the sensitivity; the distortion is ≤1.0%; the lens has a small size and a compact structure; the lens design and adjustment adopts a centering process to improve the adjustment accuracy of the lens; an optical athermal design is adopted to eliminate thermal differences and chromatic aberrations, and athermalization is achieved within a temperature range of -40°C to +70°C.

[0012] The present invention is described in detail below with reference to the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 Schematic diagram of an optical system implemented in the present invention.

[0014] Figure 2 A schematic structural diagram of an implementation of the present invention.

[0015] Figure 3 A schematic cross-sectional view of the structure of the present invention.

[0016] Figure 4 A schematic diagram of the front fixing group structure implemented in the present invention.

[0017] Figure 5 A schematic diagram of the relay group structure implemented by the present invention.

[0018] In the figure: 1, front fixed group; 1-1, first lens group; 1-2, second lens group; 1-3, third lens group; 1-4, first lens; 1-5, first pressure ring; 1-6, second lens; 1-7, second pressure ring; 1-8, third lens; 1-9, third pressure ring; 1-10, first lens frame; 1-11, second lens frame; 1-12, third lens frame; 2, fast reflex mirror group; 2-1, 2-2, reflector; 3, relay group; 3-1, fourth lens group ; 3-2, fifth lens group; 3-3, sixth lens group; 3-4, fourth lens; 3-5, fourth pressure ring; 3-6, fifth lens; 3-7, fifth pressure ring; 3-8, sixth lens; 3-9, sixth pressure ring; 3-10, fourth lens frame; 3-11, fifth lens frame; 3-12, sixth lens frame; 4, lens body; 5, detector cold aperture; 6, detector window; 7, seventh pressure ring; 8, eighth pressure ring; 9, first lens mount; 10, second lens mount. DETAILED DESCRIPTION

[0019] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined purpose, the specific implementation methods, structural features and effects of the present invention are described in detail below in conjunction with the accompanying drawings and embodiments.

[0020] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0021] All features disclosed in this specification, or steps in all methods or processes disclosed, except mutually exclusive features and / or steps, can be combined in any manner.

[0022] Any feature disclosed in this specification (including any additional claims, abstract and drawings), unless otherwise stated, may be replaced by other equivalent or alternative features with similar purposes. That is, unless otherwise stated, each feature is only an example of a series of equivalent or similar features.

[0023] Example 1

[0024] In order to design a large field of view infrared lens, a secondary imaging system is used to achieve 100% cold aperture matching, reduce system stray light, effectively reduce volume and weight, design and control distortion, and improve the accurate output of the detected target position.

[0025] This embodiment provides a Figure 1 to Figure 5 The wide-field infrared lens shown is used in conjunction with a detector, and the resolution of the detector is 1280*1024; the wide-field infrared lens comprises a lens body 4, two front fixed groups 1 arranged above the lens body 4, the front fixed group 1 having positive optical focal length, a quick reflex mirror group 2 arranged in the lens body 4, the quick reflex mirror group 2 having a two-angle high-frequency positioning adjustment function; a relay group 3 arranged on the right side of the lens body 4, the relay group 3 also having positive optical focal length; the relay group 3 is arranged horizontally, the quick reflex mirror group 2 is at an angle of 45° with the horizontal direction, the two front fixed groups 1 are inclined 20° relative to the vertical direction, and the angle between the two front fixed groups 1 is 40°, the intersection of the optical axes of the two front fixed groups 1 coincides with the center points of the reflectors 2-1 and 2-2 of the quick reflex mirror group 2, respectively corresponding to the two angular positions of the quick reflex mirror 2, forming two optical paths, and sharing one relay group 3.

[0026] Furthermore, the quick reflex mirror group 2 adopts the GSM30 quick reflex mirror of Beijing Xunlai Optoelectronic Technology Co., Ltd. The quick reflex mirror group 2 drives the reflector to adjust the angle through the rotation of the motor, and the adjustment angle range is -10° to 10°; the quick reflex mirror group 2 completes the optical path folding and optical path switching, reducing the length and volume of the optical system. The quick reflex mirror group 2 drives the reflector through the rotation of the motor to achieve high-frequency adjustment and positioning functions of two angles, and its main function is to fix the optical path before switching.

[0027] Further, the front fixed group 1 includes a first lens group 1-1, a second lens group 1-2, a third lens group 1-3, and a seventh pressure ring 7. The first lens group 1-1, the second lens group 1-2, and the third lens group 1-3 are all arranged on a first lens seat 9 and fixed by the seventh pressure ring 7. The first lens group 1-1 includes a first lens 1-4, a first lens frame 1-10, and a first pressure ring 1-5. The first lens 1-4 is arranged in the first lens frame 1-10, and the first pressure ring 1-5 is arranged in the first The second lens group 1-2 includes a second lens 1-6, a second lens frame 1-11, and a second pressure ring 1-7. The second lens 1-6 is arranged in the second lens frame 1-11, and the second pressure ring 1-7 is arranged above the second lens 1-6. The third lens group 1-3 includes a third lens 1-8, a third lens frame 1-12, and a third pressure ring 1-9. The third lens 1-8 is arranged in the third lens frame 1-12, and the third pressure ring 1-9 is arranged above the third lens 1-8.

[0028] Further, the relay group 3 includes a fourth lens group 3-1, a fifth lens group 3-2, a sixth lens group 3-3, and an eighth pressure ring 8. The fourth lens group 3-1, the fifth lens group 3-2, and the sixth lens group 3-3 are all arranged on the second lens seat 10 and fixed by the eighth pressure ring 8. The fourth lens group 3-1 includes a fourth lens 3-4, a fourth lens frame 3-10, and a fourth pressure ring 3-5. The fourth lens 3-4 is arranged in the fourth lens frame 3-10, and the fourth pressure ring 3-5 is arranged in the fourth lens frame 3-10. The fifth lens group 3-2 includes a fifth lens 3-6, a fifth lens frame 3-11, and a fifth pressure ring 3-7. The fifth lens 3-6 is arranged in the fifth lens frame 3-11, and the fifth pressure ring 3-7 is arranged above the fifth lens 3-6. The sixth lens group 3-3 includes a sixth lens 3-8, a sixth lens frame 3-12, and a sixth pressure ring 3-9. The sixth lens 3-8 is arranged in the sixth lens frame 3-12, and the sixth pressure ring 3-9 is arranged above the sixth lens 3-8.

[0029] Furthermore, the right side of the relay group 3 corresponds to the detector window 6 , and a detector cold stop 5 is arranged on the right side of the detector window 6 .

[0030] Furthermore, the first lens 1-4 is a meniscus-shaped germanium negative lens with a concave surface facing the object side;

[0031] Furthermore, the second lens 1-6 is a meniscus positive lens with a concave surface facing the object, and the material is chalcogenide glass;

[0032] Further, the third lens 1-8 is a biconvex silicon positive lens;

[0033] Furthermore, the fourth lens 3-4 is a meniscus positive lens with a convex surface facing the object, and the material is chalcogenide glass;

[0034] Furthermore, the fifth lens 3-6 is a biconcave negative lens, and the material is zinc sulfide;

[0035] Furthermore, the sixth lens 3-8 is a biconvex positive lens, and the material is chalcogenide glass;

[0036] Furthermore, the fast-reflection mirror group 2 is located between the third lens and the fourth lens, and folds the optical path by 90°±20°;

[0037] Furthermore, among the working surfaces of the lens, the S1 surface of the first lens 1-4, the S4 surface of the second lens 1-6, the S5 surface of the third lens 1-8, the S8 surface of the fourth lens 2-4, the S10 surface of the fifth lens 3-6, and the S13 surface of the sixth lens 3-8 are aspherical surfaces, and the rest are spherical surfaces.

[0038] In the above lenses, the reflector is coated with a reflective film, and the other surfaces are coated with an anti-reflection film. Table 1 shows the optical structure parameters of the present invention.

[0039] Table 1 Optical structure parameters

[0040]

[0041]

[0042] The aspheric surfaces mentioned in the above lenses are all even-order aspheric surfaces, and their expressions are as follows:

[0043]

[0044] Where z is the distance vector height from the vertex of the aspheric surface when the aspheric surface is at a height of r along the optical axis, c represents the vertex curvature of the surface, which is equal to the inverse of the radius of curvature, c = 1 / r0, k is the cone coefficient, k = 0, α2, α3, α4, α5, α6 are high-order aspheric coefficients.

[0045] Table 2 shows the aspheric coefficients of surfaces S1, S4, S5, S8, S10, and S13:

[0046] Table 2 Aspheric coefficient table

[0047] surface <![CDATA[α2]]> <![CDATA[α3]]> <![CDATA[α4]]> <![CDATA[α5]]> <![CDATA[α6]]> S1 3.705e-4 -2.184e-06 1.174e-08 1.745e-10 -1.676e-12 S4 5.7e-05 -8.569e-08 -3.284e-10 6.17e-12 -2.004e-14 S5 -1.53e-05 1.437e-08 -2.248e-11 4.433e-13 -1.303e-15 S8 -3.726e-06 -5.533e-09 1.206e-11 -1.467e-14 4.732e-18 S10 7.371e-05 -1.159e-07 -5.309e-10 3.544e-12 -5.162e-15 S13 3.103e-05 -3.258e-08 6.797e-10 -7.852e-12 2.849e-14

[0048] In summary, the large-field-of-view infrared lens uses a 1280*1024@10μm medium-wave cooled detector with a field of view angle ≥84.5°x54.2°. At the required 50lp / mm, the imaging performance is good; the F number of the optical system is 2.0, which increases the system light throughput and improves sensitivity; the distortion is ≤1.0%; the lens is small in size and compact in structure; the lens design and adjustment adopts a centering process to improve the lens adjustment accuracy; the optical athermal design is used to eliminate thermal differences and chromatic aberrations, and athermalization is achieved within the temperature range of -40℃ to +70℃.

[0049] The above contents are further detailed descriptions of the present invention in combination with specific preferred embodiments, and it cannot be determined that the specific implementation of the present invention is limited to these descriptions. For ordinary technicians in the technical field to which the present invention belongs, several simple deductions or substitutions can be made without departing from the concept of the present invention, which should be regarded as falling within the scope of protection of the present invention.

Claims

1. A wide field of view infrared lens, characterized in that: The invention comprises a lens body (4), two front fixing groups (1) arranged above the lens body (4), a quick-reflex mirror group (2) arranged inside the lens body (4), and a relay group (3) arranged on the right side of the lens body (4); the relay group (3) is arranged horizontally, the angle between the quick-reflex mirror group (2) and the horizontal direction is 45 degrees, the two front fixing groups (1) are arranged at an angle of 20 degrees relative to the vertical direction, and the angle between the two front fixing groups (1) is 40 degrees.

2. The wide-field infrared lens according to claim 1, characterized in that: The quick-reflection mirror group (2) drives the reflector mirror to adjust its angle through the rotation of the motor, and the adjustment angle range of the quick-reflection mirror group (2) is -10° to 10°.

3. The wide field of view infrared lens as claimed in claim 1, characterized in that: The front fixed group (1) comprises a first lens group (1-1), a second lens group (1-2), a third lens group (1-3), and a seventh pressure ring (7); the first lens group (1-1) comprises a first lens (1-4), a first lens frame (1-10), and a first pressure ring (1-5); the first lens (1-4) is arranged in the first lens frame (1-10), and the first pressure ring (1-5) is arranged above the first lens (1-4); the second lens group (1-2) comprises a second lens (1-6 ), a second lens frame (1-11), and a second pressure ring (1-7), the second lens (1-6) is arranged in the second lens frame (1-11), and the second pressure ring (1-7) is arranged above the second lens (1-6); the third lens group (1-3) includes a third lens (1-8), a third lens frame (1-12), and a third pressure ring (1-9), the third lens (1-8) is arranged in the third lens frame (1-12), and the third pressure ring (1-9) is arranged above the third lens (1-8).

4. The wide-field infrared lens according to claim 1, characterized in that: The relay group (3) includes a fourth lens group (3-1), a fifth lens group (3-2), a sixth lens group (3-3), and an eighth pressure ring (8); the fourth lens group (3-1) includes a fourth lens (3-4), a fourth lens frame (3-10), and a fourth pressure ring (3-5); the fourth lens (3-4) is arranged in the fourth lens frame (3-10), and the fourth pressure ring (3-5) is arranged above the fourth lens (3-4); the fifth lens group (3-2) includes a fifth lens (3-6) , a fifth lens frame (3-11), and a fifth pressure ring (3-7), wherein the fifth lens (3-6) is arranged in the fifth lens frame (3-11), and the fifth pressure ring (3-7) is arranged above the fifth lens (3-6); the sixth lens group (3-3) comprises a sixth lens (3-8), a sixth lens frame (3-12), and a sixth pressure ring (3-9), wherein the sixth lens (3-8) is arranged in the sixth lens frame (3-12), and the sixth pressure ring (3-9) is arranged above the sixth lens (3-8).

5. The wide-field infrared lens according to claim 1, characterized in that: The right side of the relay group (3) corresponds to the detector window (6), and a detector cold stop (5) is arranged on the right side of the detector window (6).

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