Internal splicing large-view-field long-wave infrared lens and imaging method

Abstract

The invention relates to the technical field of internally-spliced large-view-field long-wave infrared lenses, in particular to an internally-spliced large-view-field long-wave infrared lens and an imaging method.The internally-spliced large-view-field long-wave infrared lens comprises a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens and a detector which are sequentially arranged in the light incidence direction; the right side surface of the sixth lens is an image surface, and the detector is obtained by splicing a plurality of detection unit arrays; by optimizing the design of the lenses, the requirements of large view field and large aperture are met at the same time, a one-time imaging structural form is adopted, the axial size is short, the distortion is small, the imaging quality is good, the energy concentration ratio is high, the structure is simple, and the stability is high.

Description

Technical Field

[0001] The present invention relates to the technical field of internally spliced ​​large-field-of-view long-wave infrared mirrors, and in particular to an internally spliced ​​large-field-of-view long-wave infrared lens and an imaging method. Background Art

[0002] Infrared optical systems are a type of passive detection optical system with obvious functions. Such systems can detect, locate and continuously track objects and targets that emit infrared rays under infrared background radiation and other interference. Therefore, they have broad application prospects in target search, early warning detection, forest fire prevention and other fields.

[0003] The ability of an optical lens to search and detect targets depends on the optical system's field of view, while its target detection capability depends on the optical system's aperture. Furthermore, a large field of view and high resolution are conflicting requirements. Therefore, achieving both a large field of view and high resolution requires a detector with a large target surface. Meanwhile, achieving high detection capability requires a large aperture. These design requirements for a large field of view, large relative aperture, and large target surface significantly increase the complexity of optical system design. Summary of the Invention

[0004] The purpose of the present invention is to provide an internally spliced ​​large-field-of-view long-wave infrared lens and an imaging method to solve the technical problem that the current long-wave infrared lens is difficult to meet the requirements of a large field of view, a large relative aperture and a large target surface.

[0005] The present invention solves the above-mentioned technical problems by: An internally spliced ​​large-field-of-view long-wave infrared lens comprises a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, and a detector, which are sequentially arranged along the incident direction of light. The left side of the first lens is an object plane, the right side of the sixth lens is an image plane, and the detector is obtained by splicing a plurality of detection unit arrays.

[0006] It is further defined that the first lens has positive optical power curved toward the image side, the second lens has negative optical power curved toward the image side, the third lens has negative optical power curved toward the image side, the fourth lens has positive optical power curved toward the object side, the fifth lens has negative optical power curved toward the object side, and the sixth lens has positive optical power curved toward the object side.

[0007] It is further defined that the first lens is a Ge lens, the second lens is a Ge lens, the third lens is an IRG27 lens, the fourth lens is a meniscus ZnS lens, the fifth lens is a meniscus ZnS lens, and the sixth lens is a meniscus IRG23 lens.

[0008] It is further defined that the front surface of the first lens is spherical, and the back surface is a diffractive aspherical surface; the front surface of the second lens is aspherical, and the back surface is aspherical; the front surface of the third lens is spherical, and the back surface is aspherical; the front surface of the fourth lens is aspherical, and the back surface is spherical; the front surface of the fifth lens is aspherical, and the back surface is aspherical; the front surface of the sixth lens is aspherical, and the back surface is aspherical.

[0009] It is further defined that the conic coefficient of the first lens is -0.85, and the conic coefficient of the aspheric surface of the rear surface of the second lens is -5.71×10 -5 The cone coefficient of the third lens is -3.24, the cone coefficient of the fourth lens is 100, and the cone coefficient of the aspheric surface of the rear surface of the sixth lens is -0.52.

[0010] It is further defined that the air gap between the first lens and the second lens is 26.35mm~32.21mm, the air gap between the second lens and the third lens is 0.90mm~1.10mm, the air gap between the third lens and the fourth lens is 12.97mm~15.85mm, the air gap between the fourth lens and the fifth lens is 21.28mm~26.00mm, the air gap between the fifth lens and the sixth lens is 4.50mm~5.50mm, and the air gap between the sixth lens and the detector is 3.73mm~4.55mm.

[0011] It is further defined that the thickness of the first lens is 27 mm to 33 mm, the thickness of the second lens is 10.95 mm to 13.39 mm, the thickness of the third lens is 15.23 mm to 18.61 mm, the thickness of the fourth lens is 21.46 mm to 26.22 mm, the thickness of the fifth lens is 9.86 mm to 12.05 mm, and the thickness of the sixth lens is 27 mm to 33 mm.

[0012] It is further defined that the resolution of the detection unit is 1280 pixels×1024 pixels, and the size of a single pixel is 25 μm×25 μm.

[0013] It is further defined that the number of the detection units is six, and the resolution of the detector is 2560 pixels×3072 pixels.

[0014] A method for imaging an internally spliced ​​large-field-of-view long-wave infrared lens utilizes the aforementioned internally spliced ​​large-field-of-view long-wave infrared lens, wherein light sequentially passes through a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens to form an image on a detector.

[0015] The beneficial effects of the present invention are: The present invention meets the requirements of large field of view and large aperture by optimizing the design between lenses, adopts a one-time imaging structure, has a short axial size, small distortion, good imaging quality, high energy concentration, simple structure and high stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a structural diagram of the spliced ​​large-field-of-view long-wave infrared lens in the present invention; Figure 2 This is a schematic plan view of the detector of the present invention; Figure 3 This is an MTF curve diagram of the optical system with a spatial frequency of 20lp / mm according to the present invention; Figure 4 is a distortion curve diagram of the present invention; Figure 5 This is an enclosing circle energy curve diagram of the optical system of the present invention.

[0017] In the figure, 1 is the first lens; 2 is the second lens; 3 is the third lens; 4 is the fourth lens; 5 is the fifth lens; 6 is the sixth lens; and 7 is the detector. DETAILED DESCRIPTION

[0018] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0019] Example 1 refer to Figure 1 The present invention provides an internally spliced ​​large-field-of-view long-wave infrared lens, comprising a lens barrel and an optical system arranged in the lens barrel. The optical system comprises a first lens 1, a second lens 2, a third lens 3, a fourth lens 4, a fifth lens 5, a sixth lens 6 and a detector 7, which are sequentially arranged along the incident direction of light. The left side of the first lens 1 is an object plane, the right side of the sixth lens 6 is an image plane, and the detector 7 is obtained by splicing a plurality of detection unit arrays.

[0020] To further illustrate, the first lens 1 is a meniscus Ge lens with positive focal power bending toward the image side, the second lens 2 is a meniscus Ge lens with negative focal power bending toward the image side, the third lens 3 is a meniscus IRG27 lens with negative focal power bending toward the image side, the fourth lens 4 is a meniscus ZNS lens with positive focal power bending toward the object side, the fifth lens 5 is a meniscus ZNS lens with negative focal power bending toward the object side, and the sixth lens 6 is a meniscus IRG23 lens with positive focal power bending toward the object side.

[0021] Among them, the meniscus Ge lens with positive focal length bent toward the image side converges the large-field light entering the optical system, and the meniscus Ge lens with negative focal length bent toward the image side and the meniscus IRG27 lens with negative focal length bent toward the image side diverge the converged light, so that the aberrations of the large-field optical system are better balanced.

[0022] The meniscus ZNS lens with positive optical power bending toward the object, the meniscus ZNS lens with negative optical power bending toward the object, and the meniscus IRG23 lens with positive optical power bending toward the object are all bent toward the object, and have a symmetrical structure with the first lens 1, the second lens 2 and the third lens 3. They have good correction performance for spherical aberration, chromatic aberration and coma, and converge the light again to form an image on the detector 7.

[0023] The air gap between the first lens 1 and the second lens 2 is 26.35mm~32.21mm, the air gap between the second lens 2 and the third lens 3 is 0.90mm~1.10mm, the air gap between the third lens 3 and the fourth lens 4 is 12.97mm~15.85mm, the air gap between the fourth lens 4 and the fifth lens 5 is 21.28mm~26.00mm, the air gap between the fifth lens 5 and the sixth lens 6 is 4.50mm~5.50mm, and the air gap between the sixth lens 6 and the detector 7 is 3.73mm~4.55mm.

[0024] The thickness of the first lens 1 is 27 mm to 33 mm, the thickness of the second lens 2 is 10.95 mm to 13.39 mm, the thickness of the third lens 3 is 15.23 mm to 18.61 mm, the thickness of the fourth lens 4 is 21.46 mm to 26.22 mm, the thickness of the fifth lens 5 is 9.86 mm to 12.05 mm, and the thickness of the sixth lens 6 is 27 mm to 33 mm.

[0025] Example 2 Based on the internally stitched large field of view long-wave infrared lens described in Example 1, this embodiment provides an internally stitched large field of view long-wave infrared lens. The relevant parameters of the first lens 1, the second lens 2, the third lens 3, the fourth lens 4, the fifth lens 5 and the sixth lens 6 are shown in Table 1: Table 1 Lens parameters of the internally spliced ​​large field of view long-wave infrared lens

[0026]

[0027] Among them, K is the cone coefficient, A, B and C are all even-order aspheric coefficients, that is, high-order correction terms; C1, C2, C3 and C4 are diffraction surface phase coefficients.

[0028] refer to Figure 2In order to increase the target surface size and improve the imaging quality, the detector 7 can be obtained by splicing multiple detection unit arrays.

[0029] The resolution of the detection unit is 1280 pixels × 1024 pixels, the size of a single pixel is 25 μm × 25 μm, and the number of detection units can be selected to be six. By splicing the six detection units, the resolution of the detector 7 is 2560 pixels × 3072 pixels.

[0030] As a result, the internally stitched large-field-of-view long-wave infrared lens recorded in this embodiment has a focal length of 216 mm, an entrance pupil diameter of 160 mm, an F number of 1.35, a field of view of 20°×16.8°, and is suitable for a large-target infrared detector with a high resolution of 3072 pixels×2560 pixels and a single pixel size of 25 μm×25 μm. The total length is 342 mm, meeting the requirements of large field of view, large target surface, and large relative aperture.

[0031] refer to Figure 3 In this embodiment, at a spatial frequency of 20 lp / mm, the MTF is better than 0.4, and the image quality is good.

[0032] refer to Figure 4 and Figure 5 In this embodiment, 80% of the energy of the enclosing circle is concentrated in two pixels, and the distortion is less than 0.1%, which has good imaging quality and meets the requirements for target detection.

[0033] Example 3 This embodiment provides an imaging method for an internally stitched large-field-of-view long-wave infrared lens. Based on the internally stitched large-field-of-view long-wave infrared lens described in Example 2, light passes through the first lens 1, the second lens 2, the third lens 3, the fourth lens 4, the fifth lens 5 and the sixth lens 6 in sequence to complete imaging on the detector 7.

[0034] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, it should be understood by those skilled in the art that the technical solutions described in the aforementioned embodiments may still be modified, or some or all of the technical features thereof may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the present invention.

Claims

1. An internally spliced ​​large field of view long-wave infrared lens, characterized in that: The invention comprises a first lens (1), a second lens (2), a third lens (3), a fourth lens (4), a fifth lens (5), a sixth lens (6) and a detector (7) which are sequentially arranged along the incident direction of light, wherein the left side of the first lens (1) is an object plane, the right side of the sixth lens (6) is an image plane, and the detector (7) is obtained by splicing a plurality of detection unit arrays.

2. The internally spliced ​​large field of view long-wave infrared lens according to claim 1, characterized in that: The first lens (1) has a positive focal length and is bent toward the image side; the second lens (2) has a negative focal length and is bent toward the image side; the third lens (3) has a negative focal length and is bent toward the image side; the fourth lens (4) has a positive focal length and is bent toward the object side; the fifth lens (5) has a negative focal length and is bent toward the object side; and the sixth lens (6) has a positive focal length and is bent toward the object side.

3. The internally spliced ​​large field of view long-wave infrared lens according to claim 1, characterized in that: The first lens (1) is a Ge lens, the second lens (2) is a Ge lens, the third lens (3) is an IRG27 lens, the fourth lens (4) is a meniscus ZnS lens, the fifth lens (5) is a meniscus ZnS lens, and the sixth lens (6) is a meniscus IRG23 lens.

4. The internally spliced ​​large field of view long-wave infrared lens according to claim 1, characterized in that: The front surface of the first lens (1) is a spherical surface, and the rear surface is a diffraction aspheric surface; the front surface of the second lens (2) is an aspheric surface, and the rear surface is an aspheric surface; the front surface of the third lens (3) is a spherical surface, and the rear surface is an aspheric surface; the front surface of the fourth lens (4) is an aspheric surface, and the rear surface is a spherical surface; the front surface of the fifth lens (5) is an aspheric surface, and the rear surface is an aspheric surface; the front surface of the sixth lens (6) is an aspheric surface, and the rear surface is an aspheric surface.

5. The internally spliced ​​large field of view long-wave infrared lens according to claim 1, characterized in that: The conic coefficient of the first lens (1) is -0.85, and the conic coefficient of the aspheric surface of the rear surface of the second lens (2) is -5.71×10 -5 The cone coefficient of the third lens (3) is -3.24, the cone coefficient of the fourth lens (4) is 100, and the cone coefficient of the aspheric surface of the rear surface of the sixth lens (6) is -0.

52.

6. The internally spliced ​​large field of view long-wave infrared lens according to claim 1, characterized in that: The air gap between the first lens (1) and the second lens (2) is 26.35 mm to 32.21 mm, the air gap between the second lens (2) and the third lens (3) is 0.90 mm to 1.10 mm, the air gap between the third lens (3) and the fourth lens (4) is 12.97 mm to 15.85 mm, the air gap between the fourth lens (4) and the fifth lens (5) is 21.28 mm to 26.00 mm, the air gap between the fifth lens (5) and the sixth lens (6) is 4.50 mm to 5.50 mm, and the air gap between the sixth lens (6) and the detector (7) is 3.73 mm to 4.55 mm.

7. The internally spliced ​​large field of view long-wave infrared lens according to claim 1, characterized in that: The thickness of the first lens (1) is 27 mm to 33 mm, the thickness of the second lens (2) is 10.95 mm to 13.39 mm, the thickness of the third lens (3) is 15.23 mm to 18.61 mm, the thickness of the fourth lens (4) is 21.46 mm to 26.22 mm, the thickness of the fifth lens (5) is 9.86 mm to 12.05 mm, and the thickness of the sixth lens (6) is 27 mm to 33 mm.

8. The internally spliced, large-field-of-view, long-wave infrared lens according to any one of claims 1 to 7, characterized in that: The resolution of the detection unit is 1280 pixels×1024 pixels, and the size of a single pixel is 25 μm×25 μm.

9. The internally spliced ​​large field of view long-wave infrared lens according to claim 8, characterized in that: The number of the detection units is six, and the resolution of the detector (7) is 2560 pixels×3072 pixels.

10. An internally spliced ​​large field of view long-wave infrared lens imaging method, characterized in that: By using the internally spliced ​​large-field-of-view long-wave infrared lens as described in claim 7, light passes through the first lens (1), the second lens (2), the third lens (3), the fourth lens (4), the fifth lens (5) and the sixth lens (6) in sequence and forms an image on the detector (7).

Images