Light and thin reflective infrared and laser common-caliber detection device based on free-form surface

Abstract

The invention discloses a light and thin reflective infrared and laser common-caliber detection device based on a free-form surface. The light and thin reflective infrared and laser common-caliber detection device comprises an optical system and an imaging processing unit, wherein the optical system comprises a first reflecting mirror, a second reflecting mirror, a third reflecting mirror, a fourth reflecting mirror and a spectroscope; the imaging processing unit comprises a laser imaging module and an infrared imaging module; a light beam emitted by an object side is sequentially reflected by the first reflector, the second reflector, the third reflector and the fourth reflector and then enters the spectroscope, the light beam penetrating through the spectroscope is an infrared light beam, the light beam reflected by the spectroscope is a laser light beam, and the infrared light beam is collected by the infrared imaging module to obtain an infrared image. The laser beam is collected by the laser imaging module to obtain a laser image. According to the invention, the coaxial four-mirror optical system can be realized only by processing the two optical curved surfaces, so that the installation and adjustment difficulty is greatly reduced.

Description

Technical Field

[0001] This invention belongs to the field of optical design technology, and particularly relates to a thin and light reflective infrared and laser co-aperture detection device based on freeform surfaces. Background Technology

[0002] With technological advancements, single-mode guided detection devices can no longer meet various requirements. Therefore, combining two or more detection methods to form a common-aperture structure is a future technological trend.

[0003] Existing coplanar structures are conventional curved surface structures, which have large volumes and are difficult to implement in terms of coplanar design. Summary of the Invention

[0004] The technical problem solved by this invention is to overcome the shortcomings of the prior art and provide a thin and light reflective infrared and laser co-aperture detection device based on freeform surfaces. Only two optical surfaces need to be processed to realize a coaxial four-reflector optical system, which greatly reduces the volume and realizes co-planar design.

[0005] The objective of this invention is achieved through the following technical solution: a thin and light reflective infrared and laser co-aperture detection device based on a freeform surface, comprising: an optical system and an imaging processing unit; wherein, the optical system includes a first reflecting mirror, a second reflecting mirror, a third reflecting mirror, a fourth reflecting mirror, and a beam splitter; the imaging processing unit includes a laser imaging module and an infrared imaging module; a beam emitted from an object is reflected sequentially by the first, second, third, and fourth reflecting mirrors and then enters the beam splitter; the beam passing through the beam splitter is an infrared beam, and the beam reflected by the beam splitter is a laser beam; the infrared beam is acquired by the infrared imaging module to obtain an infrared image, and the laser beam is acquired by the laser imaging module to obtain a laser image.

[0006] In the aforementioned thin and light reflective infrared and laser co-aperture detection device based on freeform surfaces, the first reflector and the third reflector are fabricated together, and the second reflector and the fourth reflector are fabricated together.

[0007] In the aforementioned thin and light reflective infrared and laser co-aperture detection device based on freeform surfaces, the first reflector is a freeform surface, and the expression of the freeform surface of the first reflector is an XY polynomial.

[0008] In the aforementioned thin and light reflective infrared and laser co-aperture detection device based on freeform surfaces, the expression for the freeform surface of the first reflector is obtained through the following formula:

[0009]

[0010] Where 1≤i1+j1≤p1, c1 is the curvature of the first surface, and k1 is the coefficient of the first conic surface. denoted as the coefficient of the first monomial, z1 as the freeform surface of the first mirror, x1 as the x-axis coordinate of the freeform surface of the first mirror, y1 as the y-axis coordinate of the freeform surface of the first mirror, i1 as the order of x1, j1 as the order of y1, and p1 as the total number of orders.

[0011] In the aforementioned thin and light reflective infrared and laser co-aperture detection device based on freeform surfaces, the curvature c1 of the first surface is -21.5873734, the coefficient k1 of the first conic surface is -3.366318987, and A 1,0 A 0,1 A 2,0 A 1,1 A 0,2 A 3,0 A 2,1 A 1,2 A 0,3 A 3,1 A 1,3 A 5,0 A 4,1 A 3,2 A 2,3 A 1,4 A 0,5 A 5,1 A 3,3 A 1,5 A 7,0 A 6,1 A 5,2 A 4,3 A 3,4 A 2,5 A 1,6 A 0,7 A 7,1 A 5,3 A 3,5 and A 1,7 All are 0, A 4,0 -2.5926667×10 -5 A 2,2 -5.4917130×10 -5 A 0,4 -2.7507727×10 -5 A 6,0 It is 6.5125100×10 -8 A 4,2 It is 1.8037743×10 -7 A 2,4 It is 1.6738553×10 -7 A 0,6 It is 5.7029393×10-8 A 8,0 -8.6854564×10 -11 A 6,2 -2.6105990×10 -10 A 4,4 -3.3020108×10 -10 A 2,6 -2.2259432×10 -10 A 0,8 -5.9966078×10 -11 .

[0012] In the aforementioned thin and light reflective infrared and laser co-aperture detection device based on freeform surfaces, the second reflector is an aspherical surface, and the aspherical expression of the second reflector is a Qcon aspherical surface.

[0013] In the aforementioned thin and light reflective infrared and laser co-aperture detection device based on freeform surfaces, the aspherical expression of the second reflector is obtained through the following formula:

[0014]

[0015] Where c2 is the curvature of the second surface, and k2 is the coefficient of the second conic surface. Let z1 be the coefficient of the first Qcon monomial, z2 be the aspherical surface of the second mirror, x2 be the x-coordinate of the aspherical surface of the second mirror, and y2 be the y-coordinate of the aspherical surface of the second mirror. Let Qcon be the monomial of the aspherical surface of the second reflecting mirror, and i2 be... The order of the second order is p2, where p2 is the total number of second-order numbers.

[0016] In the aforementioned thin and light reflective infrared and laser co-aperture detection device based on freeform surfaces, the curvature c2 of the second surface is -14.3131384160788, the coefficient k2 of the second conic surface is -6.5068231590525, B4 is -0.429928016748411, B6 is 0.0550634272535595, and B8 is -0.00883102206390734.

[0017] In the aforementioned thin and light reflective infrared and laser co-aperture detection device based on freeform surfaces, the third reflector is a freeform surface, and the expression of the freeform surface of the third reflector is an XY polynomial.

[0018] In the aforementioned thin and light reflective infrared and laser co-aperture detection device based on freeform surfaces, the expression for the freeform surface of the third reflector is obtained through the following formula:

[0019]

[0020] Where 1≤i3+j3≤p3, c3 is the curvature of the third surface, and k3 is the coefficient of the third conic surface. denoted as the coefficient of the second monomial, z3 is the freeform surface of the third mirror, x3 is the x-axis coordinate of the freeform surface of the third mirror, y3 is the y-axis coordinate of the freeform surface of the third mirror, i3 is the order of x3, j3 is the order of y3, and p3 is the total number of third orders.

[0021] In the aforementioned thin and light reflective infrared and laser co-aperture detection device based on freeform surfaces, the curvature c3 of the third surface is -78.140192441664, and the coefficient k3 of the third conic surface is -51.9656952095324. 1,0 C 0,1 C 2,0 C 1,1 C 0,2 C 3,0 C 2,1 C 1,2 C 0,3 C 3,1 C 1,3 C 5,0 C 4,1 C 3,2 C 2,3 C 1,4 C 0,5 C 5,1 C 3,3 C 1,5 C 7,0 C 6,1 C 5,2 C 4,3 C 3,4 C 2,5 C 1,6 C 0,7 C 7,1 C 5,3 C 3,5 and C 1,7 All are 0, C 4,0 C is -0.000288034. 2,2 C is -0.00038278. 0,4 C is -0.000191294. 6,0 It is 4.4284207×10 -6 C 4,2 It is 8.4452445×10 -6 C 2,4 It is 8.5006743×10 -6 C 0,6It is 2.8046137×10 -6 C 8,0 -3.141648×10 -8 C 6,2 -9.1503124×10 -8 C 4,4 -1.3921181E×10 -7 C 2,6 -9.6029122E×10 -8 C 0,8 -2.3423771E×10 -8 .

[0022] In the above-mentioned thin and light reflective infrared and laser co-aperture detection device based on freeform surfaces, the fourth reflector is an aspherical surface, and the aspherical expression of the fourth reflector is a Qcon aspherical surface.

[0023] In the aforementioned thin and light reflective infrared and laser co-aperture detection device based on freeform surfaces, the aspherical expression of the fourth reflecting mirror is obtained through the following formula:

[0024]

[0025] Where c4 is the curvature of the fourth surface, and k4 is the coefficient of the fourth conic surface. Let z be the coefficient of the second Qcon monomial, z4 be the aspherical surface of the fourth mirror, x4 be the x-coordinate of the aspherical surface of the fourth mirror, and y4 be the y-coordinate of the aspherical surface of the second mirror. Let Qcon be the monomial of the aspherical surface of the fourth reflecting mirror, and i4 be... The order of the fourth order is p4, where p4 is the total number of fourth-order numbers.

[0026] In the aforementioned thin and light reflective infrared and laser co-aperture detection device based on freeform surfaces, the curvature c4 of the fourth surface is -19.8403666137685, the coefficient k4 of the fourth conic surface is 23.1103650732508, D4 is 0.00470536626329708, D6 is 0.00747362453983489, and D8 is 0.000288154262594372.

[0027] Compared with the prior art, the present invention has the following advantages:

[0028] (1) The present invention uses a total reflection imaging system to avoid the effects of color difference;

[0029] (2) In order to achieve high-performance infrared imaging, the present invention adopts a coaxial four-mirror scheme and at the same time imposes special constraints on the position of the curved surface, so that the primary three mirrors and the secondary four mirrors can be processed together. In this way, only the processing of two optical curved surfaces is needed to realize the coaxial four-mirror optical system, which greatly reduces the difficulty of assembly and adjustment. Attached Figure Description

[0030] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0031] Figure 1 This is a block diagram of the imaging unit principle provided in an embodiment of the present invention;

[0032] Figure 2 This is a schematic diagram of the infrared laser common aperture imaging system provided in an embodiment of the present invention;

[0033] Figure 3 This is a schematic diagram of the integrated fabrication of the infrared laser common aperture imaging system provided in the embodiment of the present invention;

[0034] Figure 4 This is an MTF curve of the infrared laser common aperture imaging system provided in an embodiment of the present invention. Detailed Implementation

[0035] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the disclosure to those skilled in the art. It should be noted that, unless otherwise specified, the embodiments and features described herein can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0036] The common-aperture structure can significantly reduce the size and weight of the seeker head and simplify the structural composition. For applications requiring both infrared and laser detection, and with miniaturization as the goal, this invention adopts a common-aperture scheme for infrared and laser. Freeform surfaces, due to their high degree of design freedom, can greatly reduce the system size and the number of optical components. Simultaneously, the common-aperture structure can significantly reduce the size and weight of the detection device and simplify the structural composition. Current common-aperture imaging schemes do not utilize freeform surfaces; this invention combines the advantages of freeform surfaces and the common-aperture design to realize a total internal reflection, lightweight, thin, and lightweight infrared and laser common-aperture composite detection device.

[0037] Figure 2 This is a schematic diagram of an infrared laser common aperture imaging system provided in an embodiment of the present invention, as shown below. Figure 2 As shown, this thin and light reflective infrared and laser co-aperture detection device based on freeform surfaces includes an optical system and an imaging processing unit. The optical system includes a first reflector 1, a second reflector 2, a third reflector 3, a fourth reflector 4, and a beam splitter 5; the imaging processing unit includes a laser imaging module 7 and an infrared imaging module 6.

[0038] The light beam emitted by the object is reflected sequentially by the first, second, third and fourth reflecting mirrors and then enters the beam splitter. The light beam that passes through the beam splitter is an infrared light beam, and the light beam reflected by the beam splitter is a laser light beam. The infrared light beam is acquired by the infrared imaging module to obtain an infrared image, and the laser light beam is acquired by the laser imaging module to obtain a laser image.

[0039] like Figure 3 As shown, the first and third reflectors are manufactured together, and the second and fourth reflectors are manufactured together.

[0040] The first reflector is a freeform surface, and the expression for the freeform surface of the first reflector is an XY polynomial. The expression for the freeform surface of the first reflector is obtained through the following formula:

[0041]

[0042] Where 1≤i1+j1≤p1, c1 is the curvature of the first surface, and k1 is the coefficient of the first conic surface. Let be the coefficients of the first monomial, z1 be the freeform surface of the first mirror, x1 be the x-axis coordinate of the freeform surface of the first mirror, y1 be the y-axis coordinate of the freeform surface of the first mirror, i1 be the order of x1, j1 be the order of y1, and p1 be the total number of orders. The origin is the center of the surface of the first mirror, the x-axis is perpendicular to the paper and pointing inwards, the z-axis is parallel to the paper and in the same direction as the optical axis, and the y-axis is perpendicular to both the x-axis and z-axis.

[0043] The curvature c1 of the first surface is -21.5873734, the coefficient k1 of the first conic surface is -3.366318987, and A 1,0 A 0,1 A 2,0 A 1,1 A 0,2 A 3,0 A 2,1 A 1,2 A 0,3 A 3,1 A 1,3 A 5,0 A 4,1A 3,2 A 2,3 A 1,4 A 0,5 A 5,1 A 3,3 A 1,5 A 7,0 A 6,1 A 5,2 A 4,3 A 3,4 A 2,5 A 1,6 A 0,7 A 7,1 A 5,3 A 3,5 and A 1,7 All are 0, A 4,0 The value is -2.5926667E-05, A 2,2 The value is -5.4917130E-05, A 0,4 The value is -2.7507727E-05, A 6,0 It is 6.5125100E-08, A 4,2 It is 1.8037743E-07, A 2,4 For 1.6738553E-07, A 0,6 For 5.7029393E-08, A 8,0 The value is -8.6854564E-11, A 6,2 For -2.6105990E-10, A 4,4 -3.3020108E-10, A 2,6 The value is -2.2259432E-10, A 0,8 It is -5.9966078E-11.

[0044] The second reflector is an aspherical surface, and its aspherical expression is Qcon aspherical. The aspherical expression of the second reflector is obtained through the following formula:

[0045]

[0046] Where c2 is the curvature of the second surface, and k2 is the coefficient of the second conic surface. Let z1 be the coefficient of the first Qcon monomial, z2 be the aspherical surface of the second mirror, x2 be the x-coordinate of the aspherical surface of the second mirror, and y2 be the y-coordinate of the aspherical surface of the second mirror. Let Qcon be the monomial of the aspherical surface of the second reflecting mirror, and i2 be... The order of the second mirror is p2, where p2 is the total number of second orders. The origin is the center of the surface of the second mirror, the x-axis is perpendicular to the paper and pointing inwards, the z-axis is parallel to the paper and in the same direction as the optical axis, and the y-axis is perpendicular to both the x-axis and z-axis.

[0047] The curvature c2 of the second surface is -14.3131384160788, the coefficient k2 of the second conic surface is -6.5068231590525, B4 is -0.429928016748411, B6 is 0.0550634272535595, and B8 is -0.00883102206390734.

[0048] The third reflecting mirror is a freeform surface, and the expression of the freeform surface of the third reflecting mirror is an XY polynomial. The expression of the freeform surface of the third reflecting mirror is obtained through the following formula:

[0049]

[0050] Where 1≤i3+j3≤p3, c3 is the curvature of the third surface, and k3 is the coefficient of the third conic surface. Let be the coefficients of the second monomial, z3 be the freeform surface of the third mirror, x3 be the x-axis coordinate of the freeform surface of the third mirror, y3 be the y-axis coordinate of the freeform surface of the third mirror, i3 be the order of x3, j3 be the order of y3, and p3 be the total number of third orders. The origin is the center of the surface of the third mirror, the x-axis is perpendicular to the paper and points inward, the z-axis is parallel to the paper and in the same direction as the optical axis, and the y-axis is perpendicular to both the x-axis and z-axis.

[0051] The curvature c3 of the third surface is -78.140192441664, and the coefficient k3 of the third conic surface is -51.9656952095324. 1,0 C 0,1 C 2,0 C 1,1 C 0,2 C 3,0 C 2,1 C 1,2 C 0,3 C 3,1 C 1,3 C 5,0 C 4,1 C 3,2 C 2,3 C 1,4 C 0,5 C 5,1 C 3,3 C 1,5 C 7,0 C 6,1 C 5,2 C 4,3C 3,4 C 2,5 C 1,6 C 0,7 C 7,1 C 5,3 C 3,5 and C 1,7 All are 0, C 4,0 C is -0.000288034. 2,2 C is -0.00038278. 0,4 C is -0.000191294. 6,0 It is 4.4284207E-06, C 4,2 It is 8.4452445E-06, C 2,4 It is 8.5006743E-06, C 0,6 It is 2.8046137E-06, C 8,0 The value is -3.1416489E-08, C 6,2 -9.1503124E-08, C 4,4 The value is -1.3921181E-07, C 2,6 -9.6029122E-08, C 0,8 It is -2.3423771E-08.

[0052] The fourth reflecting mirror is an aspherical surface, and the aspherical surface expression of the fourth reflecting mirror is Qcon aspherical surface.

[0053] The aspherical expression of the fourth reflecting mirror is obtained by the following formula:

[0054]

[0055] Where c4 is the curvature of the fourth surface, and k4 is the coefficient of the fourth conic surface. Let z be the coefficient of the second Qcon monomial, z4 be the aspherical surface of the fourth mirror, x4 be the x-coordinate of the aspherical surface of the fourth mirror, and y4 be the y-coordinate of the aspherical surface of the second mirror. Let Qcon be the monomial of the aspherical surface of the fourth reflecting mirror, and i4 be... The order of the fourth mirror is p4, where p4 is the total number of fourth-order mirrors. The origin is the center of the surface of the fourth mirror, the x-axis is perpendicular to the paper and pointing inwards, the z-axis is parallel to the paper and in the same direction as the optical axis, and the y-axis is perpendicular to both the x-axis and z-axis.

[0056] The curvature of the fourth surface c4 is -19.8403666137685, the coefficient of the fourth conic surface k4 is 23.1103650732508, D4 is 0.00470536626329708, D6 is 0.00747362453983489, and D8 is 0.000288154262594372.

[0057] The infrared detection system in this embodiment operates in the long-wavelength band, while laser detection typically uses the short-wavelength infrared band. In addition to considering intensity issues in high-speed environments, the filtering and transmission characteristics of optical materials also need to be taken into account. To achieve the optical design of the infrared laser common-aperture imaging system, this scheme selects a total internal reflection imaging system to avoid the influence of chromatic aberration. To achieve high-performance infrared imaging, a coaxial four-mirror scheme is adopted, with special constraints added to the curved surface positions, allowing the primary three mirrors and secondary four mirrors to be fabricated as a single unit. This means that only two optical curved surfaces need to be fabricated to realize the coaxial four-mirror optical system, greatly reducing the assembly and adjustment difficulty.

[0058] The optical detection device consists of an optical system and an imaging processing unit. The optical system comprises four reflecting mirrors and a beam splitter (the first and third mirrors are fabricated as a single unit, and the second and fourth mirrors are fabricated as a single unit). After receiving a light beam emitted from an object, the beam is reflected sequentially by the four reflecting mirrors and then enters the beam splitter. The beam splitter, a plane mirror, divides the beam into two paths: a transmitted infrared beam and a reflected laser beam. The imaging processing unit includes a laser imaging module, an infrared imaging module, and an interface module.

[0059] The optical design of this system employs a progressive optimization strategy. First, an initial coaxial four-reflector spherical system is established. After setting relevant constraints, the system gradually evolves from spherical surfaces to quadric surfaces, ultimately using Q-type polynomial aspherical surfaces. Q-type polynomial aspherical surfaces can improve the surface profile of the aspherical surface by controlling its root-mean-square dip deviation or root-mean-square slope, which is beneficial for aberration correction. Considering fabrication performance, 8th-order Q-type polynomial aspherical surfaces are used for the four reflecting surfaces, achieving image quality close to the diffraction limit.

[0060] Based on the 8th-order Q-type polynomial, freeform surfaces are used to further reduce the size of the optical system. Freeform surfaces are used for the first and third reflectors, achieving lightweight and high integration of the optical imaging system. In the design, manufacturing, and measurement of freeform surfaces, it is necessary to determine the mathematical description of the optical freeform surface. Currently, there are various mathematical descriptions for optical freeform surfaces. The XY polynomial freeform surface is a relatively classic description method. Its expression is a superposition of quadratic surfaces and XY polynomials. The p-order XY polynomial freeform surface is shown in the following equation.

[0061]

[0062] Where c is the surface curvature, k is the conic surface coefficient, and A i,j These are the coefficients of the XY monomials. XY polynomial freeform surfaces are simple in form and can describe continuous surfaces without axes of rotational symmetry, making them convenient for fitting freeform surfaces. This surface has a high degree of freedom; an 8th-order XY polynomial freeform surface contains 46 degrees of freedom. It can be seen that freeform surfaces, as complex unconventional continuous surfaces without axes of rotational symmetry, have more variables in their mathematical expressions compared to traditional surfaces such as spheres, quadrics, and aspherics, providing a large number of design degrees of freedom for optical design. This allows freeform surfaces to describe surfaces of various shapes and possesses excellent beam control capabilities, improving the performance of optical systems. Furthermore, compared to off-axis reflection systems designed using spheres and aspherics, using freeform surfaces can significantly reduce system size and improve image quality.

[0063] In the aforementioned infrared laser common-aperture imaging system, a beam splitter is added in front of the image to separate the incident light into short-wave infrared and long-wave infrared beams, enabling semi-active laser detection and long-wave infrared imaging respectively, thus meeting the requirements of multi-mode guidance. During optical design, specific constraints are incorporated to ensure that the edge extensions of the primary mirror and the three mirrors are similar, allowing the primary mirror and the three mirrors to be fabricated together; similarly, the edge extensions of the secondary mirror and the fourth mirror are similar, allowing the secondary mirror and the four mirrors to be fabricated together. This way, the infrared laser common-aperture imaging system only requires the fabrication of two mirrors, significantly reducing assembly complexity.

[0064] The imaging processing unit includes a laser imaging module, an infrared imaging module, and an interface module. To reduce size and weight, the three imaging modules share a single FPGA processor, and the external interface uses a CamLink interface. The block diagram of the imaging unit is shown below. Figure 1 As shown in the figure. This embodiment utilizes semi-active laser and infrared imaging for target acquisition, identification, and tracking. At long range, it is necessary to combine the target's attitude information and trajectory to achieve image-based target acquisition and tracking. At medium and short ranges, target matching, target identification, and tracking are achieved.

[0065] The specifications of the infrared laser common aperture imaging system in this embodiment are as follows: Spectral range: The reflective system can accept any wavelength band. Currently, it is planned to use a long-wave infrared detector and a short-wave infrared laser detector; Focal length: 68.00 mm; Aperture: 30 mm; Field of view: 3°×3°; F number: 2.27.

[0066] The first mirror of the optical system is a freeform surface, expressed as an XY polynomial, as shown in the following equation.

[0067]

[0068] Where 1≤i1+j1≤p1, c1 is the curvature of the first surface, and k1 is the coefficient of the first conic surface.

[0069] The surface coefficients are shown in the table below:

[0070]

[0071]

[0072] The second mirror in this optical system is an aspherical surface, expressed as Qcon aspherical, as shown in the following formula:

[0073]

[0074] The surface coefficients are shown in the table below:

[0075] Serial Number item numerical values 1 curvature c -14.3131384160788 2 Conic surface constant k -6.5068231590525 3 <![CDATA[B4]]> -0.429928016748411 4 <![CDATA[B6]]> 0.0550634272535595 5 <![CDATA[B8]]> -0.00883102206390734

[0076] The third mirror in this optical system is a freeform surface, expressed as an XY polynomial, as follows:

[0077]

[0078] The surface coefficients are shown in the table below:

[0079]

[0080]

[0081] The fourth mirror in this optical system is an aspherical surface, expressed as Qcon aspherical, as shown in the following formula:

[0082]

[0083] The surface coefficients are shown in the table below:

[0084] Serial Number item numerical values 1 <![CDATA[Curvature c4]]> -19.8403666137685 2 <![CDATA[Conical surface constant k4]]> 23.1103650732508 3 <![CDATA[D4]]> 0.00470536626329708 4 <![CDATA[D6]]> 0.00747362453983489 5 <![CDATA[D8]]> 0.000288154262594372

[0085] The final MTF curve of the optical system is as follows: Figure 4 As shown, the imaging quality is close to the diffraction limit.

[0086] This embodiment uses a total internal reflection imaging system to avoid the influence of chromatic aberration. In order to achieve high-performance infrared imaging, this embodiment adopts a coaxial four-mirror scheme. At the same time, special constraints are added to the position of the curved surface, so that the primary three mirrors and the secondary four mirrors can be fabricated together. In this way, only the fabrication of two optical curved surfaces is required to realize the coaxial four-mirror optical system, which greatly reduces the difficulty of assembly and adjustment.

[0087] Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make possible changes and modifications to the technical solutions of the present invention by utilizing the methods and techniques disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solutions of the present invention shall fall within the protection scope of the technical solutions of the present invention.

Claims

1. A thin and light reflective infrared and laser co-aperture detection device based on freeform surfaces, characterized in that... include: Optical system and imaging processing unit; wherein, The optical system includes a first reflecting mirror, a second reflecting mirror, a third reflecting mirror, a fourth reflecting mirror, and a beam splitter; The imaging processing unit includes a laser imaging module and an infrared imaging module; The light beam emitted by the object is reflected sequentially by the first, second, third and fourth reflecting mirrors and then enters the beam splitter. The light beam that passes through the beam splitter is an infrared light beam, and the light beam reflected by the beam splitter is a laser light beam. The infrared light beam is acquired by the infrared imaging module to obtain an infrared image, and the laser light beam is acquired by the laser imaging module to obtain a laser image.

2. The thin and light reflective infrared and laser co-aperture detection device based on freeform surfaces according to claim 1, characterized in that: The first and third reflectors are manufactured together, and the second and fourth reflectors are manufactured together.

3. The thin and light reflective infrared and laser co-aperture detection device based on freeform surfaces according to claim 1, characterized in that: The first reflector is a freeform surface, and the expression of the freeform surface of the first reflector is an XY polynomial.

4. The thin and light reflective infrared and laser co-aperture detection device based on freeform surfaces according to claim 3, characterized in that: The expression for the freeform surface of the first reflecting mirror is obtained through the following formula: Where 1≤i1+j1≤p1, c1 is the curvature of the first surface, and k1 is the coefficient of the first conic surface. denoted as the coefficient of the first monomial, z1 as the freeform surface of the first mirror, x1 as the x-axis coordinate of the freeform surface of the first mirror, y1 as the y-axis coordinate of the freeform surface of the first mirror, i1 as the order of x1, j1 as the order of y1, and p1 as the total number of orders.

5. The thin and light reflective infrared and laser co-aperture detection device based on freeform surfaces according to claim 4, characterized in that: The first surface curvature c1 is -21.5873734, and the first conic surface coefficient k1 is -3.366318987, A -5 , -5 , -8 , -10 , 5,3 , -7 , -10 , 1,6 , 6,0 , 8,0 , 2,2 , 2,4 , 0,8 , 3,5 , 4,4 , 0,7 , -5 , -11 , 1,7 , -7 , -10 , -8 , 7,1 , 6,2 , 0,4 , 0,6 , 4,0 , 4,2 , 2,6 , A 0,1 , A 2,0 , A 1,1 , A 0,2 , A 3,0 , A 2,1 , A 1,2 , A 0,3 , A 3,1 , A 1,3 , A 5,0 , A 4,1 , A 3,2 , A 2,3 , A 1,4 , A 0,5 , A 5,1 , A 3,3 , A 1,5 , A 7,0 , A 6,1 , A 5,2 , A 4,3 , A 3,4 , A 2,5 , A 1,6 , A 0,7 , A 7,1 , A 5,3 , A 3,5 and A 1,7 are all 0, A 4,0 is -2.5926667×10 <00,00034>, A 2,2 is -5.4917130×10 -5 , A 0,4 is -2.7507727×10 -5 , A 6,0 , A is 6.5125100×10 -8 , A 4,2 is (1.8037743×10 -7 , A 2,4 is 1,6738553×10 -7 , A 0,6 is 5.7029393×10 -8 , A 8,0 is -8.6854564×10 -11 , A 6,2 is -2.6105990×10 -10 , A 4,4 is -3.3020108×10 -10 , A 2,6 is -2.2259432×10 -10 , A 0,8 -5.9966078×10 -11 .

6. The thin and light reflective infrared and laser co-aperture detection device based on freeform surfaces according to claim 1, characterized in that: The second reflector is an aspherical surface, and the expression for the aspherical surface of the second reflector is Qcon aspherical surface; The aspherical expression of the second reflecting mirror is obtained by the following formula: Where c2 is the curvature of the second surface, and k2 is the coefficient of the second conic surface. Let z1 be the coefficient of the first Qcon monomial, z2 be the aspherical surface of the second mirror, x2 be the x-coordinate of the aspherical surface of the second mirror, and y2 be the y-coordinate of the aspherical surface of the second mirror. Let Qcon be the monomial of the aspherical surface of the second reflecting mirror, and i2 be... The order of the second order is p2, where p2 is the total number of second-order numbers.

7. The thin and light reflective infrared and laser co-aperture detection device based on freeform surfaces according to claim 6, characterized in that: The curvature c2 of the second surface is -14.3131384160788, the coefficient k2 of the second conic surface is -6.5068231590525, B4 is -0.429928016748411, B6 is 0.0550634272535595, and B8 is -0.00883102206390734.

8. The thin and light reflective infrared and laser co-aperture detection device based on freeform surfaces according to claim 1, characterized in that: The third reflecting mirror is a freeform surface, and the expression of the freeform surface of the third reflecting mirror is an XY polynomial; The expression for the freeform surface of the third reflecting mirror is obtained through the following formula: Where 1≤i3+j3≤p3, c3 is the curvature of the third surface, and k3 is the coefficient of the third conic surface. denoted as the coefficient of the second monomial, z3 is the freeform surface of the third mirror, x3 is the x-axis coordinate of the freeform surface of the third mirror, y3 is the y-axis coordinate of the freeform surface of the third mirror, i3 is the order of x3, j3 is the order of y3, and p3 is the total number of third orders.

9. The thin and light reflective infrared and laser co-aperture detection device based on freeform surfaces according to claim 8, characterized in that: The curvature c3 of the third surface is -78.140192441664, and the coefficient k3 of the third conic surface is -51.9656952095324. 1,0 C 0,1 C 2,0 C 1,1 C 0,2 C 3,0 C 2,1 C 1,2 C 0,3 C 3,1 C 1,3 C 5,0 C 4,1 C 3,2 C 2,3 C 1,4 C 0,5 C 5,1 C 3,3 C 1,5 C 7,0 C 6,1 C 5,2 C 4,3 C 3,4 C 2,5 C 1,6 C 0,7 C 7,1 C 5,3 C 3,5 and C 1,7 All are 0, C 4,0 C is -0.000288034. 2,2 C is -0.00038278. 0,4 C is -0.000191294. 6,0 It is 4.4284207×10 -6 C 4,2 It is 8.4452445×10 -6 C 2,4 It is 8.5006743×10 -6 C 0,6 It is 2.8046137×10 -6 C 8,0 -3.141648×10 -8 C 6,2 -9.1503124×10 -8 C 4,4 -1.3921181E×10 -7 C 2,6 -9.6029122E×10 -8 C 0,8 -2.3423771E×10 -8 .

10. The thin and light reflective infrared and laser co-aperture detection device based on freeform surfaces according to claim 1, characterized in that: The fourth reflecting mirror is an aspherical surface, and the aspherical surface expression of the fourth reflecting mirror is Qcon aspherical surface; The aspherical expression of the fourth reflecting mirror is obtained by the following formula: Where c4 is the curvature of the fourth surface, and k4 is the coefficient of the fourth conic surface. Let z be the coefficient of the second Qcon monomial, z4 be the aspherical surface of the fourth mirror, x4 be the x-coordinate of the aspherical surface of the fourth mirror, and y4 be the y-coordinate of the aspherical surface of the second mirror. Let Qcon be the monomial of the aspherical surface of the fourth reflecting mirror, and i4 be... The order of the fourth order, p4 is the total number of fourth-order numbers; The curvature of the fourth surface c4 is -19.8403666137685, the coefficient of the fourth conic surface k4 is 23.1103650732508, D4 is 0.00470536626329708, D6 is 0.00747362453983489, and D8 is 0.000288154262594372.

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