Long-wave infrared and visible light dual-light fusion optical system

Abstract

The invention relates to the technical field of optical imaging, in particular to a long-wave infrared and visible light dual-light fusion optical system which comprises a diaphragm, a first lens, a second lens and a third lens which are coaxially arranged in sequence, the first lens and the second lens are both meniscus lenses, the meniscus direction is far away from the diaphragm, and the third lens is far away from the diaphragm. The third lens sequentially comprises a biconvex positive lens and a biconcave negative lens which are glued along the direction far away from the diaphragm; the combination of the first lens and the second lens is used for realizing target calibration of long-wave infrared light based on different object distances; the combination of the first lens, the second lens and the third lens is used for realizing target calibration of visible light based on different object distances. According to the optical system provided by the invention, calibration of a dual-light fusion optical product based on different object distance targets can be realized, coaxial and object distance sharing of long-wave infrared light and visible light is realized, errors caused by manual operation can be avoided, the calibration efficiency is improved, and meanwhile, the space required in the calibration process can be saved.

Description

Technical Field

[0001] The present invention relates to the technical field of optical imaging, and particularly to a long-wave infrared and visible light dual-light fusion optical system. Background Art

[0002] With the rapid development of infrared imaging technology, most temperature measurement products adopt far-infrared and visible light image fusion. In order to test the accurate calibration parameters of temperature measurement products with dual-light fusion function at different working distances and improve the accuracy and stability of dual-light fusion, usually during the production of temperature measurement products with dual-light fusion function, calibration based on target marks with different object distances for long-wave infrared light and visible light is carried out for each product respectively.

[0003] When the existing temperature measurement products with dual-light fusion function are produced and tested, it is necessary to hold the product by hand to capture and perform calibration tests such as long-wave infrared light and visible light on the target mark at a certain distance. This will generate certain human errors, and because the data of target marks at different far and near distances need to be calibrated, a large test space is required. Summary of the Invention

[0004] Aiming at the technical problem in the prior art that when manually holding a dual-light fusion device to calibrate the long-wave infrared light and visible light on the target mark respectively, human errors are easily generated and a large test space is required, the present invention provides a long-wave infrared and visible light dual-light fusion optical system. The optical system includes a diaphragm, a first lens, a second lens, and a third lens arranged coaxially in sequence. The first lens and the second lens are both meniscus lenses, and the meniscus direction is away from the diaphragm. The third lens includes a cemented biconvex positive lens and a biconcave negative lens in sequence along the direction away from the diaphragm. The combination of the first lens and the second lens is used to realize the calibration of the target mark with different object distances for long-wave infrared light. The combination of the first lens, the second lens, and the third lens is used to realize the calibration of the target mark with different object distances for visible light.

[0005] Further, the front surface of the first lens is a spherical surface, and the rear surface is a binary diffraction surface. The front surface and the rear surface of the second lens are both aspherical surfaces. The first surface, the second surface, the third surface, and the fourth surface of the third lens are all spherical surfaces.

[0006] Further, the surface type characteristics of the spherical surface are determined by the radius of curvature, thickness, and diameter. The surface type characteristics of the aspherical surface are determined by the radius of curvature, thickness, diameter, and the fourth-order aspherical coefficient, the sixth-order aspherical coefficient, the eighth-order aspherical coefficient, and the tenth-order aspherical coefficient. The influence of the fourth-order aspherical coefficient, the sixth-order aspherical coefficient, the eighth-order aspherical coefficient, and the tenth-order aspherical coefficient on the aspherical surface is defined by the following formula:

[0007]

[0008] Among them, Z is the position of the aspherical surface along the optical axis at a height r, which is the sagitta distance from the vertex of the aspherical surface; c is the reciprocal of the radius of curvature; r is the radial coordinate in the direction perpendicular to the optical axis; k is the conic constant; A, B, C, D, and E are the aspherical coefficients of the second order, fourth order, sixth order, eighth order, and tenth order respectively.

[0009] Further, the fourth-order, sixth-order, eighth-order, and tenth-order aspherical coefficients of the rear surface of the first lens are 1.5814E-06, -6.3228E-10, 6.2538E-13, and 2.0914E-16 in sequence; the fourth-order, sixth-order, eighth-order, and tenth-order aspherical coefficients of the front surface of the second lens are 2.4668E-06, -2.1104E-9, 1.9286E-12, and -2.6184E-16 in sequence; the fourth-order, sixth-order, eighth-order, and tenth-order aspherical coefficients of the rear surface of the second lens are 6.4869E-07, -7.6454E-10, 5.1640E-13, and -1.1102E-16 in sequence.

[0010] Further, the phase expression of the binary diffractive surface is:

[0011]

[0012] Among them, N is the number of polynomial coefficients, ρ is the normalized radial aperture coordinate, and Ai is the coefficient of the 2i-th power of ρ; M is the diffraction order, and M is taken as 1.

[0013] Further, when N is taken as 3, ρ 2 =-0.1085, ρ 4 =1.5025E-06, ρ 6 =-8.5779E-09.

[0014] Further, for the front surface of the first lens, its radius of curvature is -98.501 mm, its thickness is 10 mm, and its diameter is 49 mm; for the rear surface of the first lens, its radius of curvature is -92.061 mm, its thickness is 4.86 mm, and its diameter is 54 mm; for the front surface of the second lens, its radius of curvature is -66.283 mm, its thickness is 12 mm, and its diameter is 54 mm; for the rear surface of the second lens, its radius of curvature is -70.079 mm, its thickness is 9.54 mm, and its diameter is 60 mm; for the first surface of the third lens, its radius of curvature is 288.148 mm, its thickness is 8 mm, and its diameter is 60 mm; for the second surface of the third lens, its radius of curvature is -89.679 mm, its thickness is 6 mm, and its diameter is 60 mm; for the third surface of the third lens, its radius of curvature is -89.679 mm, its thickness is 6 mm, and its diameter is 60 mm; for the fourth surface of the third lens, its radius of curvature is 265.618 mm, its thickness is 431.93 mm, and its diameter is 60 mm.

[0015] Further, the field of view angle of this optical system is ±5°, the focal length is 400 mm, and the entrance pupil diameter is 40 mm.

[0016] Further, this optical system is applicable to long-wave infrared in the 8 μm - 12 μm band and visible light with wavelengths of 430 nm - 680 nm.

[0017] Further, this optical system realizes coaxial and common object distance for long-wave infrared light and visible light by adding or removing the third lens.

[0018] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0019] First, it is beneficial to avoid errors caused by manual operation and improve the calibration efficiency. The present invention realizes the target calibration of long-wave infrared light based on different object distances through the lens group composed of the first lens and the second lens, and realizes the target calibration of visible light based on different object distances through the lens group composed of the first lens, the second lens, and the third lens. Moreover, during the test process, coaxial and common object distance for long-wave infrared and visible light are achieved, that is, a target at the same position for the two bands is realized, avoiding errors caused by frequent manual movement of the dual-light fusion product or the target, which is more conducive to realizing automatic calibration and improving the calibration efficiency of the dual-light fusion product.

[0020] 2. Save the space required for testing. The present invention realizes the optical performance of a telephoto lens group for long-wave infrared with a wavelength of 8-12μm through the combination of a first lens and a second lens; realizes the optical performance of a telephoto lens group for visible light with a wavelength of 430nm-680nm through the combination of a first lens, a second lens and a third lens, and then moves the target to achieve testing at multiple object distances, so as to solve the problem of the large testing space required when calibrating a dual-light fusion product based on different object-distance targets in long-wave infrared and visible light. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only the embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained according to the provided drawings without creative efforts.

[0022] Figure 1 FIG. 1 is a schematic structural diagram of the application of a long-wave infrared and visible light dual-light fusion optical system to a dual-light fusion product based on target calibration;

[0023] Figure 2 FIG. 2 is a schematic diagram of a long-wave infrared and visible light dual-light fusion optical system provided by an embodiment of the present invention for realizing target calibration for long-wave infrared light;

[0024] Figure 3 FIG. 3 is a schematic diagram of a long-wave infrared and visible light dual-light fusion optical system provided by an embodiment of the present invention for realizing target calibration for visible light.

[0025] In the figure: 1, the first lens; 2, the second lens; 3, the third lens; 4, the target; 5, the dual-light fusion optical system; 6, the visible light lens; 7, the long-wave infrared objective lens. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0026] In order to make the purpose, technical solutions and advantages of the present invention clearer, the following will further describe the present invention in detail with reference to the drawings and embodiments. Obviously, the specific embodiments described here are only used to explain the present invention, which are part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0027] See Figures 1-3, A long-wave infrared and visible light dual-light fusion optical system includes a diaphragm, a first lens 1, a second lens 2, and a third lens 3 arranged coaxially in sequence. The first lens 1 and the second lens 2 are both meniscus lenses, and the meniscus directions are away from the diaphragm. The third lens 3 includes a cemented biconvex positive lens and a biconcave negative lens in sequence along the direction away from the diaphragm. The combination of the first lens 1 and the second lens 2 is used to achieve target calibration for long-wave infrared light based on different object distances. The combination of the first lens 1, the second lens 2, and the third lens 3 is used to achieve target calibration for visible light based on different object distances.

[0028] In practical applications, refer to Figure 1 The schematic structural diagram of a long-wave infrared and visible light dual-light fusion optical system shown in the figure is applied to the target calibration of a dual-light fusion product. The dual-light fusion optical system 5 is composed of a diaphragm, a first lens 1, a second lens 2, and a third lens 3 arranged coaxially in sequence. When testing an optical product with a dual-light fusion function, the optical product with the dual-light fusion function includes a visible light lens 6 and a long-wave infrared objective lens 7. The optical product with the dual-light fusion function, the dual-light fusion optical system 5, and the target 4 are arranged coaxially in sequence for calibrating the long-wave infrared light and the visible light based on targets with different object distances. In this way, the calibration process realizes the coaxial and co-object distance of the long-wave infrared and the visible light, that is, realizes a target at the same position for the two bands, avoids the errors caused by the artificial frequent movement of the dual-light fusion product or the target, is more conducive to realizing automatic calibration, and improves the calibration efficiency of the dual-light fusion product. Moreover, the teleconverter group formed by the combination of the first lens 1 and the second lens 2 realizes the optical performance of the long-wave infrared teleconverter; the teleconverter group formed by the combination of the first lens 1, the second lens 2, and the third lens 3 realizes the optical performance of the visible light teleconverter, and then the target is moved to realize the test of multiple object distances. In this way, the problem that a large test space is required when calibrating the dual-light fusion product for long-wave infrared and visible light based on targets with different object distances can be solved.

[0029] Furthermore, define the surface of the first lens 1 and the second lens 2 close to the diaphragm as the front surface, and the other surface as the rear surface. The front surface of the first lens 1 is a spherical surface, and the rear surface is a binary diffraction surface; the front surface of the second lens 2 is an aspherical surface, and the rear surface is an aspherical surface; define the surfaces that the light of the third lens 3 passes through in sequence along the direction away from the diaphragm as the first surface, the second surface, the third surface, and the fourth surface. The first surface of the third lens 3 is a spherical surface, the second surface is a spherical surface, the third surface is a spherical surface, and the fourth surface is a spherical surface.

[0030] Further, the surface profile characteristics of the above-mentioned lens are determined by the radius of curvature, thickness, and diameter; the surface profile characteristics of the above-mentioned aspherical lens are determined by the radius of curvature, thickness, diameter, and fourth-order aspherical coefficient, sixth-order aspherical coefficient, eighth-order aspherical coefficient, and tenth-order aspherical coefficient; the influence of the fourth-order aspherical coefficient, sixth-order aspherical coefficient, eighth-order aspherical coefficient, and tenth-order aspherical coefficient on the aspherical surface is defined by the following formula:

[0031]

[0032] Wherein, Z is the position of the aspherical surface along the optical axis at a height r, the sagitta distance from the vertex of the aspherical surface; c is the reciprocal of the radius of curvature; r is the radial coordinate in the direction perpendicular to the optical axis; k is the conic constant; A, B, C, D, and E are the second-order, fourth-order, sixth-order, eighth-order, and tenth-order aspherical coefficients respectively.

[0033] More specifically, the fourth-order, sixth-order, eighth-order, and tenth-order aspherical coefficients of the rear surface of the first lens are 1.5814E-06, -6.3228E-10, 6.2538E-13, and 2.0914E-16 in sequence; the fourth-order, sixth-order, eighth-order, and tenth-order aspherical coefficients of the front surface of the second lens are 2.4668E-06, -2.1104E-9, 1.9286E-12, and -2.6184E-16 in sequence; the fourth-order, sixth-order, eighth-order, and tenth-order aspherical coefficients of the rear surface of the second lens are 6.4869E-07, -7.6454E-10, 5.1640E-13, and -1.1102E-16 in sequence.

[0034] Specifically, the relevant parameters of the aspherical formula for the front surface of the first lens 1, the front surface of the second lens 2, and the rear surface of the second lens 2 are shown in Table 1 below.

[0035] Table 1

[0036] Serial number Category k A B C D E 1 Rear surface of the first lens 1 0 0 1.5814E-06 -6.3228E-10 6.2538E-13 2.0914E-16 2 Front surface of the second lens 2 0 0 2.4668E-06 -2.1104E-9 1.9286E-12 -2.6184E-16 3 Rear surface of the second lens 2 0 0 6.4869E-07 -7.6454E-10 5.1640E-13 -1.1102E-16

[0037] Further, the phase expression of the binary diffractive surface on the rear surface of the first lens 1 is:

[0038]

[0039] Wherein, N is the number of polynomial coefficients, ρ is the normalized radial aperture coordinate, and Ai is the coefficient of the 2i-th power of ρ; M is the diffraction order, and M is taken as 1.

[0040] When N is taken as 3, ρ 2 =-0.1085, ρ 4 =1.5025E-06, ρ 6 =-8.5779E-09.

[0041] Specifically, the relevant parameters of the binary diffraction surface are shown in Table II below.

[0042] Table II

[0043] Serial number Surface type M <![CDATA[ρ 2 > <![CDATA[ρ 4 > <![CDATA[ρ 6 > 1 Binary diffractive surface 1 -0.1085 1.5025E-06 -8.5779E-09

[0044] Furthermore, for the front surface of the first lens 1, its radius of curvature is -98.501 mm, its thickness is 10 mm, and its diameter is 49 mm; for the rear surface of the first lens 1, its radius of curvature is -92.061 mm, its thickness is 4.86 mm, and its diameter is 54 mm; for the front surface of the second lens 2, its radius of curvature is -66.283 mm, its thickness is 12 mm, and its diameter is 54 mm; for the rear surface of the second lens 2, its radius of curvature is -70.079 mm, its thickness is 9.54 mm, and its diameter is 60 mm; for the first surface of the third lens 3, its radius of curvature is 288.148 mm, its thickness is 8 mm, and its diameter is 60 mm; for the second surface of the third lens 3, its radius of curvature is -89.679 mm, its thickness is 6 mm, and its diameter is 60 mm; for the third surface of the third lens 3, its radius of curvature is -89.679 mm, its thickness is 6 mm, and its diameter is 60 mm; for the fourth surface of the third lens 3, its radius of curvature is 265.618 mm, its thickness is 431.93 mm, and its diameter is 60 mm.

[0045] Specifically, the surface types and relevant parameters of the first lens 1, the second lens 2, and the third lens 3 of the optical system provided in this embodiment are as shown in Table III below.

[0046] Table III

[0047]

[0048] Furthermore, the binary diffraction surface is a 2n-level step, where n is determined according to the diffraction efficiency and the actual manufacturing process difficulty. The binary diffraction surface is not limited to a 2-level step, but can be made into a 2n-level step, and the diffraction efficiency is related to the number of steps. The more steps, the higher the efficiency. For example, for a binary diffraction surface with 2-level steps, the first-order diffraction efficiency is 40.5%, and for a binary diffraction surface with 4-level steps, the first-order diffraction efficiency reaches 81.1%. However, as the number of steps increases, the process becomes relatively complex. Therefore, when designing, the number of steps can be determined according to the diffraction efficiency and the actual manufacturing process difficulty.

[0049] Furthermore, the field of view angle of this optical system is ±5°, the focal length is 400 mm, and the entrance pupil diameter is 40 mm.

[0050] Furthermore, this optical system is applicable to long-wave infrared in the 8 μm - 12 μm band and visible light with wavelengths of 430 nm - 680 nm.

[0051] Furthermore, the optical system realizes coaxial and co-object distance for long-wave infrared light and visible light by adding or removing the third lens. Specifically, when conducting a calibration test of visible light based on a target at a certain object distance for a dual-band fusion optical product, the third lens 3 is removed, and only the diaphragm and the lens group composed of the first lens 1 and the second lens 2 are retained to achieve the optical performance of a long-wave infrared teleconverter. Then, based on this object distance, the third lens 3 is added, and the diaphragm, the first lens 1, the second lens 2, and the third lens 3 are retained to achieve the optical performance of a visible light teleconverter. This process can realize coaxial and co-object distance for long-wave infrared light and visible light, enabling a target at the same position for both bands, and avoiding errors caused by frequent manual movement of the dual-band fusion product or the target. Then, the target is moved, and the above process is repeated to achieve the calibration of the dual-band fusion optical product for targets at different object distances.

[0052] The dual-band fusion optical system for long-wave infrared and visible light provided in this embodiment can realize the calibration of the dual-band fusion optical product based on targets at different object distances, achieve coaxial and co-object distance for long-wave infrared light and visible light, which is beneficial to avoiding errors caused by manual operation, improving the calibration efficiency, facilitating automatic calibration, and saving the space required for the calibration process.

[0053] The above embodiments only represent the preferred implementation modes of the present invention, and their descriptions are relatively specific and detailed. However, they should not be construed as limiting the scope of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the appended claims.

Claims

1. A long-wave infrared and visible light dual-light fusion optical system, characterized in that: The optical system includes an aperture, a first lens, a second lens, and a third lens which are coaxially arranged in sequence. The first lens and the second lens are both meniscus lenses, and the meniscus direction is far away from the aperture. The third lens includes a glued double convex positive lens and a double concave negative lens in sequence along the direction away from the aperture. The combination of the first lens and the second lens is used to realize target calibration based on different object distances for long-wave infrared light. The combination of the first lens, the second lens and the third lens is used to realize target calibration based on different object distances for visible light.

2. The long-wave infrared and visible light dual-light fusion optical system according to claim 1, characterized in that: The front surface of the first lens is a spherical surface, and the rear surface is a binary diffraction surface; the front surface and the rear surface of the second lens are both aspherical surfaces; the first surface, the second surface, the third surface and the fourth surface of the third lens are all spherical surfaces.

3. The long-wave infrared and visible light dual-light fusion optical system according to claim 2, characterized in that: The surface characteristics of the spherical surface are determined by the radius of curvature, thickness, and diameter; the surface characteristics of the aspherical surface are determined by the radius of curvature, thickness, diameter, and fourth-order aspherical coefficients, sixth-order aspherical coefficients, eighth-order aspherical coefficients, and tenth-order aspherical coefficients; the influence of the fourth-order aspherical coefficients, sixth-order aspherical coefficients, eighth-order aspherical coefficients, and tenth-order aspherical coefficients on the aspherical surface is defined by the following formula: Among them, Z is the position of the aspheric surface at a height r along the optical axis, and the distance vector height from the vertex of the aspheric surface; c is the inverse of the radius of curvature; r is the radial coordinate in the direction perpendicular to the optical axis; k is the quadratic curve constant; A, B, C, D, and E are the second-order, fourth-order, sixth-order, eighth-order, and tenth-order aspheric coefficients, respectively.

4. The long-wave infrared and visible light dual-light fusion optical system according to claim 3, characterized in that: The fourth-order, sixth-order, eighth-order and tenth-order aspheric coefficients of the back surface of the first lens are 1.5814E-06, -6.3228E-10, 6.2538E-13 and 2.0914E-16 respectively; the fourth-order, sixth-order, eighth-order and tenth-order aspheric coefficients of the front surface of the second lens are 2.4668E-06, -2.1104E-9, 1.9286E-12 and -2.6184E-16 respectively; the fourth-order, sixth-order, eighth-order and tenth-order aspheric coefficients of the back surface of the second lens are 6.4869E-07, -7.6454E-10, 5.1640E-13 and -1.1102E-16 respectively.

5. The long-wave infrared and visible light dual-light fusion optical system according to claim 2, characterized in that: The phase expression of the binary diffraction surface is: Where N is the number of polynomial coefficients, ρ is the normalized radial aperture coordinate, Ai is the coefficient of ρ raised to the power of 2i; M is the diffraction order, which is taken as 1.

6. The long-wave infrared and visible light dual-light fusion optical system according to claim 5, characterized in that: When N is 3, ρ 2 =-0.1085,ρ 4 =1.5025E-06,ρ 6 =-8.5779E-09.

7. The long-wave infrared and visible light dual-light fusion optical system according to claim 2, characterized in that: The radius of curvature of the front surface of the first lens is -98.501mm, the thickness is 10mm, and the diameter is 49mm; the radius of curvature of the rear surface of the first lens is -92.061mm, the thickness is 4.86mm, and the diameter is 54mm; the radius of curvature of the front surface of the second lens is -66.283mm, the thickness is 12mm, and the diameter is 54mm; the radius of curvature of the rear surface of the second lens is -70.079mm, the thickness is 9.54mm, and the diameter is 60mm; The first surface of the third lens has a curvature radius of 288.148 mm, a thickness of 8 mm and a diameter of 60 mm; the second surface of the third lens has a curvature radius of -89.679 mm, a thickness of 6 mm and a diameter of 60 mm; the third surface of the third lens has a curvature radius of -89.679 mm, a thickness of 6 mm and a diameter of 60 mm; the fourth surface of the third lens has a curvature radius of 265.618 mm, a thickness of 431.93 mm and a diameter of 60 mm.

8. The long-wave infrared and visible light dual-light fusion optical system according to claim 2, characterized in that: The optical system has a field of view of ±5°, a focal length of 400 mm, and an entrance pupil diameter of 40 mm.

9. The long-wave infrared and visible light dual-light fusion optical system according to claim 2, characterized in that: The optical system is suitable for long-wave infrared in the 8μm-12μm band and visible light in the 430nm-680nm wavelength.

10. The long-wave infrared and visible light dual-light fusion optical system according to claim 2, characterized in that: The optical system realizes the co-axis and object distance of long-wave infrared light and visible light by adding or removing the third lens.

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