Long-wave infrared uncooled switchable dual field lens

Abstract

The utility model relates to optical technology field especially, and it is a kind of long-wave infrared uncooled switching type double field lens, including the front fixed group, switching group, rear fixed group are sequentially arranged with front fixed group along optical axis from object side to image side, still include long-wave uncooled detector, long-wave uncooled detector is located the side of rear fixed group, and long-wave uncooled detector and the optical axis direction of rear fixed group are identical, the first lens of first fixed group includes the material is germanium single crystal, the both sides of first lens surface are respectively provided with the first mirror surface of positive lens and the second mirror surface of aspherical surface, switching group includes the second lens of material is germanium single crystal and the third lens of material is germanium single crystal, rear fixed group includes the fourth lens of material is germanium single crystal and the fifth lens of material is lydian glass;The utility model uses switching type mode to carry out field of view conversion, optical structure is compact, switching speed is fast, can effectively find target and quickly identify target, with good application effect.

Description

Technical Field

[0001] This utility model relates to the field of optical technology, and in particular to a long-wave infrared uncooled switching dual-field lens. Background Technology

[0002] With the widespread application of long-wave infrared uncooled detectors in security monitoring, vehicle night vision, and industrial inspection, the requirements for the field-of-view adaptability of optical lenses are increasing. Traditional single-field-of-view lenses have the limitation of a fixed field of view, making it difficult to simultaneously meet the dual needs of large-field-of-view search and small-field-of-view detail observation. Existing dual-field-of-view switching solutions mostly use mechanical zoom or lens group replacement, which have problems such as complex structure, slow switching speed, and high cost. In addition, the optical design of the long-wave infrared band is limited by the difficulty of material selection and aberration correction. Existing dual-field-of-view lenses generally have defects such as insufficient thermal sensitivity and poor image quality stability, which affect the imaging effect of detectors in complex environments.

[0003] Therefore, there is an urgent need for a compact, efficient switching, and image-quality optimized dual-field-of-view lens to meet the requirements of uncooled detectors for rapid response and high-precision observation in dynamic scenes. This invention aims to solve the above-mentioned technical bottlenecks through innovative optical layout and switching mechanism. Utility Model Content

[0004] To overcome the shortcomings of existing dual-field-of-view lenses, such as insufficient thermal sensitivity and poor image quality stability, which affect the imaging performance of detectors in complex environments, a cut-in / cut-out dual-field-of-view lens adapted to long-wavelength uncooled detectors is proposed. Its operating wavelength is 8-12 micrometers, with focal lengths of 120mm and 240mm, and apertures of 0.85 and 0.95 respectively. It is adapted to uncooled detectors with a resolution of 640x512 and a pixel size of 12 micrometers. The total length of the optical system is 361.44mm, and the maximum aperture is 256mm. Unlike traditional axial switching field-of-view designs, the switching group in this design has a focal length of 120mm when cut into the optical axis and 240mm when cut out of the optical axis.

[0005] The technical solution of this utility model is: a long-wave infrared uncooled switching dual-field lens, which includes a front fixed group, a switching group and a rear fixed group arranged sequentially from the object side to the image side along the optical axis, and also includes a long-wave uncooled detector, which is located on the side of the rear fixed group, and the optical axis direction of the long-wave uncooled detector and the rear fixed group are consistent.

[0006] The front fixing group includes a first lens made of germanium single crystal, and a first mirror surface that is a positive lens and a second mirror surface that is an aspherical surface are respectively provided on both sides of the surface of the first lens;

[0007] The switching group includes a second lens made of germanium single crystal and a third lens made of germanium single crystal. The two sides of the surface of the second lens are respectively the third mirror surface of the diffraction surface and the fourth mirror surface of the aspherical surface. The two sides of the surface of the third lens are respectively the fifth mirror surface of the positive lens and the sixth mirror surface of the aspherical surface.

[0008] The rear fixed assembly includes a fourth lens made of germanium single crystal and a fifth lens made of sapphire glass. The fourth lens has a seventh mirror surface that is a positive lens and an eighth mirror surface that is a diffraction surface on both sides of its surface. The fifth lens has a ninth mirror surface that is a positive lens and a tenth mirror surface that is a diffraction surface on both sides of its surface.

[0009] The long-wavelength uncooled detector includes a protective window and an imaging surface made of germanium single crystal.

[0010] As a preferred option, the lens meets the following parameters:

[0011] EFL=120 / 240mm, F / #=0.85 / 0.95, total length of optical system including detector part=361.44mm, resolution of imaging plane 314 is 640x512, pixel size 12μmx12μm.

[0012] Preferably, the first lens is a meniscus with its convex surface facing the object side, the first lens surface is coated with a diamond-like carbon film, and the second lens surface is coated with an anti-reflective film.

[0013] Preferably, the switching group is used to change the focal length of the dual-field lens, the second lens is a meniscus with its concave surface facing the object side, the third lens is a biconvex lens, and anti-reflective coatings are applied to the third, fourth, fifth, and sixth mirror surfaces.

[0014] Preferably, the fourth lens is a meniscus with its convex surface facing the object, the fifth lens is a meniscus with its convex surface facing the object, and the seventh, eighth, ninth, and tenth mirror surfaces are all coated with anti-reflective coatings.

[0015] Preferably, the horizontal field of view of the lens is:

[0016]

[0017] Preferably, the aspherical surfaces in the lens element satisfy the following expression:

[0018]

[0019] in For an aspherical surface along the optical axis at a height of When the position is such that the distance from the vertex of the non-spherical surface is the sag, Represents the curvature at the vertices of the surface. The conic coefficient, , , , , It represents the higher-order aspheric coefficient.

[0020] Preferably, the diffraction surface in the lens element satisfies the following expression:

[0021]

[0022] in The phase of the diffraction plane. It is the planned radius of the diffraction surface. , is the phase coefficient of the diffraction surface.

[0023] The beneficial effects of this utility model are:

[0024] This long-wave infrared uncooled switching dual-field-of-view lens offers good imaging quality at both focal lengths. It features a compact structure, reasonable tolerances, simple assembly and adjustment, and is easy to mass-produce. In particular, it can cut in and out the lens group without changing the overall length of the optical system, thus achieving different focal length states. It uses a switching method to change the field of view, has a compact optical structure, and a fast switching speed. It can effectively detect and quickly identify targets, demonstrating excellent application performance. Attached Figure Description

[0025] Figure 1 The diagram shown is an optical system diagram of Embodiment 1 of the long-wave infrared uncooled switching dual-field-of-view lens of this utility model;

[0026] Figure 2 The image shown is the MTF diagram of the optical system of Embodiment 1 of the long-wave infrared uncooled switching dual-field-of-view lens of this utility model;

[0027] Figure 3 The diagram shown is a dot plot of the optical system of Embodiment 1 of the long-wave infrared uncooled switching dual-field-of-view lens of this utility model.

[0028] Figure 4 The image shown is a field curvature distortion diagram of the optical system of Embodiment 1 of the long-wave infrared uncooled switching dual-field-of-view lens of this utility model.

[0029] Figure 5 The diagram shown is an optical system diagram of Embodiment 2 of the long-wave infrared uncooled switching dual-field-of-view lens of this utility model;

[0030] Figure 6 The image shown is the MTF diagram of the optical system of Embodiment 2 of the long-wave infrared uncooled switching dual-field-of-view lens of this utility model;

[0031] Figure 7The diagram shown is a dot diagram of the optical system of Embodiment 2 of the long-wave infrared uncooled switching dual-field-of-view lens of this utility model.

[0032] Figure 8 The image shown is a field curvature distortion diagram of the optical system of the long-wave infrared uncooled switching dual-field lens of this utility model, according to Embodiment 2.

[0033] Explanation of reference numerals in the attached drawings: 110, first lens; S1, first mirror surface; S2, second mirror surface; 122, second lens; 124, third lens; S3, third mirror surface; S4, fourth mirror surface; S5, fifth mirror surface; S6, sixth mirror surface; 132, fourth lens; 134, fifth lens; S7, seventh mirror surface; S8, eighth mirror surface; S9, ninth mirror surface; S10, tenth mirror surface; 312, protective window; 314, imaging surface. Detailed Implementation

[0034] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0035] Example 1

[0036] Please see Figures 1-4 This utility model provides an embodiment with a focal length of 120mm: a long-wave infrared uncooled switching dual-field lens, including a front fixed group, a switching group, and a rear fixed group arranged sequentially along the optical axis from the object side to the image side, and also includes a long-wave uncooled detector, which is located on the side of the rear fixed group, and the optical axis direction of the long-wave uncooled detector and the rear fixed group are consistent.

[0037] The front fixing group includes a first lens 110 made of germanium single crystal, and a first mirror surface S1, which is a positive lens, and a second mirror surface S2, which is an aspherical surface, are respectively provided on both sides of the surface of the first lens 110.

[0038] The switching group includes a second lens 122 made of germanium single crystal and a third lens 124 made of germanium single crystal. The two sides of the surface of the second lens 122 are respectively the third mirror surface S3 of the diffraction surface and the fourth mirror surface S4 of the aspherical surface. The two sides of the surface of the third lens 124 are respectively the fifth mirror surface S5 of the positive lens and the sixth mirror surface S6 of the aspherical surface.

[0039] The rear fixed assembly includes a fourth lens 132 made of germanium single crystal and a fifth lens 134 made of glaze glass. The two sides of the surface of the fourth lens 132 are the seventh mirror surface S7 of the positive lens and the eighth mirror surface S8 of the diffraction surface, respectively. The two sides of the surface of the fifth lens 134 are the ninth mirror surface S9 of the positive lens and the tenth mirror surface S10 of the diffraction surface, respectively.

[0040] The long-wavelength uncooled detector includes a protective window 312 made of germanium single crystal and an imaging surface 314.

[0041] The lens meets the following parameters:

[0042] EFL=120 / 240mm, F / #=0.85 / 0.95, total length of optical system including detector part=361.44mm, resolution of imaging plane 314 is 640x512, pixel size 12μmx12μm.

[0043] The first lens 110 is a meniscus-shaped lens with its convex surface facing the object side. The first mirror surface S1 is coated with a diamond-like carbon film, and the second mirror surface S2 is coated with an anti-reflective film.

[0044] The switching group is used to change the focal length of the dual-field lens. The second lens 122 is a meniscus with its concave surface facing the object side, and the third lens 124 is a biconvex lens. Anti-reflective coatings are applied to the third mirror surface S3, the fourth mirror surface S4, the fifth mirror surface S5, and the sixth mirror surface S6.

[0045] The fourth lens 132 is a meniscus with its convex surface facing the object side, the fifth lens 134 is a meniscus with its convex surface facing the object side, and anti-reflective coatings are applied to the seventh mirror surface S7, the eighth mirror surface S8, the ninth mirror surface S9, and the tenth mirror surface S10.

[0046] Example 2

[0047] Please see Figures 5-8 This utility model provides an embodiment with a focal length of 240mm: a long-wave infrared uncooled switching dual field of view lens, including a front fixed group and a rear fixed group arranged sequentially along the optical axis from the object side to the image side, and also includes a long-wave uncooled detector, which is located on the side of the rear fixed group, and the optical axis direction of the long-wave uncooled detector and the rear fixed group are consistent.

[0048] The front fixing group includes a first lens 110 made of germanium single crystal, and a first mirror surface S1, which is a positive lens, and a second mirror surface S2, which is an aspherical surface, are respectively provided on both sides of the surface of the first lens 110.

[0049] The rear fixed assembly includes a fourth lens 132 made of germanium single crystal and a fifth lens 134 made of glaze glass. The two sides of the surface of the fourth lens 132 are the seventh mirror surface S7 of the positive lens and the eighth mirror surface S8 of the diffraction surface, respectively. The two sides of the surface of the fifth lens 134 are the ninth mirror surface S9 of the positive lens and the tenth mirror surface S10 of the diffraction surface, respectively.

[0050] The long-wavelength uncooled detector includes a protective window 312 made of germanium single crystal and an imaging surface 314.

[0051] The lens meets the following parameters:

[0052] EFL=120 / 240mm, F / #=0.85 / 0.95, total length of optical system including detector part=361.44mm, resolution of imaging plane 314 is 640x512, pixel size 12μmx12μm.

[0053] The first lens 110 is a meniscus-shaped lens with its convex surface facing the object side. The first mirror surface S1 is coated with a diamond-like carbon film, and the second mirror surface S2 is coated with an anti-reflective film.

[0054] The switching group is used to change the focal length of the dual-field lens. The second lens 122 is a meniscus with its concave surface facing the object side, and the third lens 124 is a biconvex lens. Anti-reflective coatings are applied to the third mirror surface S3, the fourth mirror surface S4, the fifth mirror surface S5, and the sixth mirror surface S6.

[0055] The fourth lens 132 is a meniscus with its convex surface facing the object side, the fifth lens 134 is a meniscus with its convex surface facing the object side, and anti-reflective coatings are applied to the seventh mirror surface S7, the eighth mirror surface S8, the ninth mirror surface S9, and the tenth mirror surface S10.

[0056] The optical structural parameters of the lens at focal lengths of 120mm and 240mm are shown in the table below:

[0057] ;

[0058] The aspherical surfaces mentioned in the five lenses above are all even-order aspherical surfaces, and their expressions are as follows:

[0059]

[0060] in For an aspherical surface along the optical axis at a height of When the position is such that the distance from the vertex of the non-spherical surface is the sag, Represents the curvature at the vertices of the surface. The conic coefficient, , , , , It represents the higher-order aspheric coefficient.

[0061] The aspherical coefficients of surfaces S2, S3, S4, S6, S8, and S10 are shown in the table below:

[0062] ;

[0063] The diffraction surfaces mentioned in the five lenses above are expressed as follows:

[0064]

[0065] in The phase of the diffraction plane. It is the planned radius of the diffraction surface. , is the phase coefficient of the diffraction surface.

[0066] The diffraction coefficients of S3, S8, and S10 are shown in the table below:

[0067] ;

[0068] The working principle is that of a dual-field-of-view lens adapted to long-wavelength uncooled detectors. Its working wavelength is 8-12 micrometers, with focal lengths of 120mm and 240mm, and apertures of 0.85 and 0.95 respectively. It is adapted to uncooled detectors with a resolution of 640x512 and a pixel size of 12 micrometers. The total length of the optical system is 361.44mm, and the maximum aperture is 256mm. Unlike the traditional axial switching field-of-view design, the focal length of this design is 120mm when the switching group is on the optical axis and 240mm when it is off the optical axis.

[0069] This embodiment is for illustrative purposes only and is not intended to limit the scope of the present invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the present invention, and these equivalent forms also fall within the scope defined by the appended claims.

Claims

1. A long-wave infrared uncooled switching dual-field-of-view lens, comprising a front fixed group, a switching group, and a rear fixed group arranged sequentially along the optical axis from the object side to the image side, characterized in that: It also includes a long-wavelength uncooled detector, which is located on the side of the rear fixed group, and the optical axis of the long-wavelength uncooled detector and the rear fixed group are aligned. The front fixing group includes a first lens (110) made of germanium single crystal. The first lens (110) has a first mirror surface (S1) which is a positive lens and a second mirror surface (S2) which is an aspherical surface on both sides of its surface. The switching group includes a second lens (122) made of germanium single crystal and a third lens (124) made of germanium single crystal. The two sides of the surface of the second lens (122) are the third mirror surface (S3) of the diffraction surface and the fourth mirror surface (S4) of the aspherical surface, respectively. The two sides of the surface of the third lens (124) are the fifth mirror surface (S5) of the positive lens and the sixth mirror surface (S6) of the aspherical surface, respectively. The rear fixed assembly includes a fourth lens (132) made of germanium single crystal and a fifth lens (134) made of glaze glass. The fourth lens (132) has a seventh mirror surface (S7) of positive lens and an eighth mirror surface (S8) of diffraction surface on both sides of its surface. The fifth lens (134) has a ninth mirror surface (S9) of positive lens and a tenth mirror surface (S10) of diffraction surface on both sides of its surface. The long-wavelength uncooled detector includes a protective window (312) made of germanium single crystal and an imaging surface (314).

2. The long-wave infrared uncooled switching dual-field-of-view lens according to claim 1, characterized in that: The lens meets the following parameters: EFL=120 / 240mm, F / #=0.85 / 0.95, total length of optical system including detector part=361.44mm, resolution of imaging plane (314) is 640x512, pixel size 12μmx12μm.

3. The long-wave infrared uncooled switching dual-field-of-view lens according to claim 1, characterized in that: The first lens (110) is a meniscus with its convex surface facing the object side. The first mirror surface (S1) is coated with a diamond-like carbon film, and the second mirror surface (S2) is coated with an anti-reflective film.

4. The long-wave infrared uncooled switching dual-field-of-view lens according to claim 1, characterized in that: The switching group is used to change the focal length of the dual field-of-view lens. The second lens (122) is a meniscus with its concave surface facing the object side, and the third lens (124) is a biconvex lens. Anti-reflective coatings are applied to the third mirror surface (S3), the fourth mirror surface (S4), the fifth mirror surface (S5), and the sixth mirror surface (S6).

5. The long-wave infrared uncooled switching dual-field-of-view lens according to claim 1, characterized in that: The fourth lens (132) is a meniscus with its convex surface facing the object side, the fifth lens (134) is a meniscus with its convex surface facing the object side, and anti-reflective coatings are applied to the seventh mirror (S7), the eighth mirror (S8), the ninth mirror (S9) and the tenth mirror (S10).

6. The long-wave infrared uncooled switching dual-field-of-view lens according to claim 1, characterized in that: The horizontal field of view of the lens is: .

7. A long-wave infrared uncooled switching dual-field-of-view lens according to claim 1, characterized in that: Aspherical surfaces in a lens element satisfy the following expression: ； in For an aspherical surface along the optical axis at a height of When the position is such that the distance from the vertex of the non-spherical surface is the sag, Represents the curvature at the vertices of the surface. The conic coefficient, , , , , It represents the higher-order aspheric coefficient.

8. A long-wave infrared uncooled switching dual-field-of-view lens according to claim 1, characterized in that: The diffraction planes in a lens element satisfy the following expression: ； in The phase of the diffraction plane. It is the planned radius of the diffraction surface. , is the phase coefficient of the diffraction surface.

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