Scanning type optical system and design method

Abstract

The invention relates to the technical field of optical system design, in particular to a scanning type optical system and a design method.On the basis of an existing imaging or detecting system, a double-risky prism unit is additionally arranged, and an optical axis deflection model of the double-risky prism unit is established; deriving an optical axis direction vector and an optical axis scanning track based on a Snell law vector form; baF2 and D-ZLAF50 are glued to form a Lessli prism, and the achromatism of a wide spectrum of 400-1000nm is realized by optimizing a wedge angle and a material; and the double-riski prism unit is cascaded with an imaging or detection system, and the view field of the system is expanded by adjusting the rotation speed matching ratio. According to the invention, an optical axis deflection model and system design method of the double-Lessli prism are provided for the first time, large-view-field (60-degree) dynamic scanning is realized, and wide-spectrum achromatic design (400-1000nm) is considered.

Description

Technical Field

[0001] The present invention belongs to the technical field of optical system design, and particularly relates to a scanning optical system and a design method thereof. Background Art

[0002] A Risley prism is an optical element capable of deflecting and controlling light, and it has relatively wide applications in the field of light control and related optical imaging fields (such as lidar, biomedicine, optical communication, infrared countermeasure, machine vision, super-resolution imaging, etc.). In the field of lidar, by deflecting the laser light and combining corresponding control algorithms, laser light scanning within a certain range can be achieved. In addition, a rotating Risley prism system is also applied to optoelectronic tracking systems and imaging systems, which can control the deflection direction of the optical axis of the system according to the azimuth of the target and in combination with relevant control algorithms to achieve dynamic tracking of the target and dynamic scanning imaging within a large field of view. At the same time, in the field of biomedical imaging, a typical example is the endoscope system. The rotating Risley prism system can increase the depth of field by reducing the numerical aperture of the optical system, while improving the image quality and meeting the application requirements of large-field-of-view imaging of the endoscope system.

[0003] For the design of a scanning optical system based on a rotating Risley prism, the most important issues to consider are the chromatic aberration problem introduced by the Risley prism and the distortion problem caused by light deflection. For the distortion problem, according to the discussions among scholars in relevant research institutions, the method of image processing can already be used to correct the distortion problem caused by light refraction in the Risley prism. For the solution to chromatic aberration, methods such as gluing prisms, grating prisms, introducing binary surfaces, and introducing metasurfaces are usually adopted for the design of an achromatic system. However, currently, there is no relevant discussion and design on wide-band achromatism for the design method of a scanning optical system based on a rotating Risley prism. Among them, for the primary achromatic problem of the Risley prism, according to relevant literature research, in the prior art, relevant scholars have discussed and achieved an achromatic rotating Risley prism with a working band in the visible light band (deflection angles of 10° and 19.5°). However, for the achromatic rotating Risley prism designed by the above-mentioned relevant scholars, a wide-spectrum achromatic Risley prism is not considered. Therefore, wide-band achromatic design cannot be achieved, which greatly limits the application of the scanning optical system based on the rotating Risley prism in large-field-of-view and wide-spectrum scenarios. Summary of the Invention

[0004] In view of this, the present invention aims to provide a scanning optical system and a design method, which for the first time apply a rotating double Risley prism to the design of a scanning optical system, achieving a scanning design in a wide spectral range (400 nm - 1000 nm) and a large deflection range (15° - 18°), and obtaining a large-field-of-view and wide-spectral scanning optical system for space target detection.

[0005] To achieve the above object, the technical solution of the present invention is realized as follows: On the one hand, the present invention provides a scanning optical system, including: an optical system body for imaging or detecting, and a double Risley prism unit for regulating the deflection of the optical axis. The double Risley prism unit includes a first Risley prism and a second Risley prism with adjacent faces parallel to each other, and the first Risley prism and the second Risley prism can rotate coaxially; Both the first Risley prism and the second Risley prism are prepared by gluing with BaF 2 and D-ZLAF50 materials for achromatism in the 400 - 1000 nm band.

[0006] Preferably, the wedge angles of the first Risley prism and the second Risley prism are adjustable.

[0007] Preferably, the light deflection angle of the double Risley prism unit is in the range of 15° to 18°.

[0008] Preferably, the front surface of the first Risley prism is BaF 2 , and the rear surface is D-ZLAF50; the front surface of the second Risley prism is D-ZLAF50, and the rear surface is BaF 2 .

[0009] Preferably, the refractive index of the BaF 2 material is 1.47, and the Abbe number is 81.60; the refractive index of the D-ZLAF50 material is 1.80, and the Abbe number is 45.49.

[0010] On the other hand, the present invention provides a scanning optical system, including: Adding a double Risley prism unit for regulating the deflection of the optical axis on the optical system body for imaging or detecting. The double Risley prism unit includes a first Risley prism and a second Risley prism with adjacent faces parallel to each other, and the first Risley prism and the second Risley prism can rotate coaxially; Deriving the optical axis direction vector of the light after being processed by the double Risley prism unit based on the vector form of Snell's law, and obtaining the optical axis scanning trajectory according to the relative rotation angle of the first Risley prism and the second Risley prism; Designing the materials and wedge angles of the first Risley prism and the second Risley prism according to the field-of-view requirements of the scanning optical system.

[0011] Preferably, the front surface of the first Risley prism is BaF 2 , and the rear surface is D-ZLAF50; the front surface of the second Risley prism is D-ZLAF50, and the rear surface is BaF 2 .

[0012] Preferably, the field of view of the scanning optical system is equal to the field of view of the optical system body for imaging or detection plus twice the field of view of the double Risley prism unit.

[0013] Compared with the prior art, the present invention can achieve the following beneficial effects: The present invention first applies a rotating Risley prism to a scanning optical system, precisely controls the optical axis deflection by rotating the Risley prism, solves the problem of limited field of view of traditional scanning optical systems, and realizes the design of a scanning optical system with an ultra-wide spectrum in the working band of 400nm - 1000nm and a deflection ability of 15° - 18°, expanding the application of the Risley prism in the fields of space target detection imaging, light control, etc.

[0014] In addition, the present invention optimizes the design of the Risley prism, solves the problem that traditional Risley prisms cannot balance wide spectrum and achromatism, glues two materials of BaF 2 and D-ZLAF50 to prepare a Risley prism, effectively controls the chromatic aberration of the Risley prism in the working band of 400nm - 1000nm within a reasonable range, and then adjusts the wedge angle of the Risley prism, combined with the chromatic aberration requirements of a specific optical system, so that the light deflection angle of the double Risley prism unit can be controlled within the range of 15° - 18°, realizing the application of wide spectrum, large field of view, and low chromatic aberration. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The schematic embodiments and descriptions of the present invention are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings: Figure 1 is a structural diagram of a scanning optical system provided according to an embodiment of the present invention; Figure 2 is a schematic diagram of a method for designing a scanning optical system provided according to an embodiment of the present invention; Figure 3 is a schematic diagram of the rotation state 1 of a double Risley prism unit provided according to an embodiment of the present invention; Figure 4 is a schematic diagram of the rotation state 2 of a double Risley prism unit provided according to an embodiment of the present invention; Figure 5Schematic diagram of the rotation state 3 of the double Risley prism unit provided according to an embodiment of the present invention Figure 6 is the standard spot diagram of the double Risley prism unit in rotation state 1 provided according to an embodiment of the present invention; Figure 7 is the standard spot diagram of the double Risley prism unit in rotation state 2 provided according to an embodiment of the present invention; Figure 8 is the standard spot diagram of the double Risley prism unit in rotation state 3 provided according to an embodiment of the present invention; Figure 9 is the schematic diagram of the rotation state 1 (field of view 0° - 30°) of the scanning optical system of the cascaded optical system body provided according to an embodiment of the present invention; Figure 10 is the standard spot diagram of the scanning optical system of the cascaded optical system body in rotation state 1 provided according to an embodiment of the present invention; Figure 11 is the lateral chromatic aberration diagram of the scanning optical system of the cascaded optical system body in rotation state 1 provided according to an embodiment of the present invention; Figure 12 is the enclosed energy distribution diagram of the scanning optical system of the cascaded optical system body in rotation state 1 provided according to an embodiment of the present invention; Figure 13 is the relative illumination diagram of the scanning optical system of the cascaded optical system body in rotation state 1 provided according to an embodiment of the present invention; Figure 14 is the schematic diagram of the rotation state 2 (field of view -15° - 15°) of the scanning optical system of the cascaded optical system body provided according to an embodiment of the present invention; Figure 15 is the standard spot diagram of the scanning optical system of the cascaded optical system body in rotation state 2 provided according to an embodiment of the present invention; Figure 16 is the lateral chromatic aberration diagram of the scanning optical system of the cascaded optical system body in rotation state 2 provided according to an embodiment of the present invention; Figure 17 is the enclosed energy distribution diagram of the scanning optical system of the cascaded optical system body in rotation state 2 provided according to an embodiment of the present invention; Figure 18 is the relative illumination diagram of the scanning optical system of the cascaded optical system body in rotation state 2 provided according to an embodiment of the present invention; Figure 19Schematic diagram of the rotational state 3 (field of view -30° to 0°) of the scanning optical system of the cascaded optical system body provided according to an embodiment of the present invention.

[0016] The reference numerals therein include: Optical system body 1, double Risley prism unit 2, first Risley prism 21, second Risley prism 22, full field of view 3, partial field of view 4, chief ray of the central field of view 5, chief ray of the marginal field of view 6, vignetting phenomenon 7. Detailed implementation manners

[0017] In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and do not constitute a limitation to the present invention. Similar elements in different embodiments are labeled with related similar reference numerals. In the following embodiments, many details are described to enable a better understanding of the present invention. However, those skilled in the art can easily recognize that some of the features can be omitted in different situations, or can be replaced by other elements, materials, or methods. In some cases, some operations related to the present invention are not shown or described in the specification, which is to avoid the core part of the present invention being overwhelmed by excessive description. For those skilled in the art, it is not necessary to describe these related operations in detail, and they can fully understand the related operations according to the description in the specification and general technical knowledge in the art.

[0018] It should be noted that, without conflict, the embodiments and features in the embodiments of the present invention can be combined with each other to form various embodiments. At the same time, the steps or actions in the method description can also be adjusted in the order that can be obviously understood by those skilled in the art. Therefore, the various sequences in the specification and drawings are only for clearly describing a certain embodiment and do not mean that they are the necessary sequences, unless it is stated that a certain sequence must be followed.

[0019] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention. In addition, the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first", "second", etc. may explicitly or implicitly include one or more of such features. In the description of the present invention, unless otherwise specified, the meaning of "a plurality" is two or more.

[0020] In the description of the present invention, it should be noted that unless otherwise clearly defined and limited, the terms "mounted", "connected", "coupled" should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood through specific situations.

[0021] The present invention will be described in detail below with reference to the drawings and in conjunction with embodiments.

[0022] Please refer to Figure 1 , in an embodiment of the present invention, a scanning optical system is provided. The double-rotating Risley prism is applied to the existing optical system to design and construct a scanning optical system. Specifically, on the basis of the optical system body 1 for imaging or detection, a double Risley prism unit 2 is added. The double Risley prism unit 2 is composed of two coaxially placed and rotatable Risley prisms, namely the first Risley prism 21 and the second Risley prism 22. The adjacent faces of the first Risley prism 21 and the second Risley prism 22 are parallel to each other, and the first Risley prism 21 and the second Risley prism 22 rotate coaxially. Both the first Risley prism 21 and the second Risley prism 22 are wedge-shaped prisms. When light passes through the first Risley prism 21 and the second Risley prism 22, the light will be deflected. The deflection ability of the first Risley prism 21 and the second Risley prism 22 to light is mainly determined by the following two factors: First, the material of the Risley prism. Different materials have different refractive indices. The higher the refractive index of the material, the greater the deflection angle of the light in the Risley prism.

[0023] Second, the wedge angle of the Risley prism. The larger the wedge angle, the greater the deflection angle of the light. The wedge angles of the first Risley prism 21 and the second Risley prism 22 are adjustable.

[0024] By optimizing the material and wedge angle of the Risley prism, the deflection ability of the double Risley prism unit 2 to light can meet the scanning range requirements of the scanning optical system. During the relative rotation of the first Risley prism 21 and the second Risley prism 22, by adjusting the relative rotation angle of the first Risley prism 21 and the second Risley prism 22, the deflection angle of the light can be changed, thereby changing the scanning position of the light main axis and changing the instantaneous imaging field of view. When the initial angle difference and rotation speed ratio of the first Risley prism 21 and the second Risley prism 22 are specific, different scanning trajectories of the light main axis can be achieved. The double Risley prism unit 2 can precisely control the light in the system and scan the field of view to complete the construction of the scanning optical system. As the first Risley prism 21 and the second Risley prism 22 rotate relatively, the deflection angle of the optical axis of the optical fiber also changes, and the instantaneous imaging field of view also changes accordingly, that is, the local field of view 4 in a certain state when the first Risley prism 21 and the second Risley prism 22 rotate relatively, so as to be able to scan the field of view, and thus realize the scanning imaging or detection of a larger field of view.

[0025] In order to achieve achromatic design in a wide wavelength band, the embodiments of the present invention further optimize the preparation materials of the first Risley prism 21 and the second Risley prism 22, such as Figure 3 shown, both the first Risley prism 21 and the second Risley prism 22 adopt a glued mirror design, and the front surface of the first Risley prism 21 uses BaF 2 , and the rear surface uses D-ZLAF50; the front surface of the second Risley prism 22 uses D-ZLAF50, and the rear surface uses BaF 2 , so that the chromatic aberration of the first Risley prism 21 and the second Risley prism 22 in the working wavelength band of 400nm - 1000nm is controlled within a reasonable range, where BaF 2The refractive index of the (barium fluoride) material is 1.47, and the Abbe number is 81.60; the refractive index of the D-ZLAF50 (Chengdu Guangming Glass Material) material is 1.80, and the Abbe number is 45.49. Through this design, the chromatic aberration problem of the Risley prism in the wide wavelength range of 400nm - 1000nm is solved, and the light deflection angle of the double Risley prism unit 2 can reach more than 15°. The maximum deflection angle of the double Risley prism unit 2 is not equal to the maximum half field angle of the entire system (the deflection angle of the Risley prism is superimposed on the basis of the field of view of the optical system). The central field principal ray 5 in the incident light can be modulated by the double Risley prism unit 2, but due to the vignetting phenomenon 7, there will be a problem that the marginal field principal ray 6 deviates. For the vignetting phenomenon 7, the vignetting can be balanced by adjusting the structure, material, etc. of the first Risley prism 21 and the second Risley prism 22.

[0026] The field of view of the entire scanning optical system is the field of view angle of the optical system body 1 + the deflection angle of the double Risley prism unit 2 × 2. For example, if the field of view of the optical system body 1 is 30°, and the maximum deflection angle of the double Risley prism unit 2 is 15°, then the overall field of view after scanning of the scanning optical system is 60° (that is, the local field of view 4 is 30 degrees, and the overall field of view of the system is 60°). The design of the embodiment of the present invention effectively improves the scanning field of view, so the system can be applied to the design of a scanning optical system that combines a Risley prism with a small deflection angle and an optical system body 1 with a medium field of view. Through the overall cascaded optimization design of the double Risley prism unit 2 and the optical system body 1, the design of a scanning optical system with a large field of view can be realized.

[0027] After actual testing, the deflection angle of the double Risley prism unit 2 of the present invention is in the range of 15° to 18°. Therefore, the scanning optical system based on the double rotating Risley prism proposed in the embodiment of the present invention has advantages such as a large field of view (more than 60°) and a wide spectrum (400nm - 1000nm), and also takes into account the achromatic aberration design in the wide spectrum of 400nm - 1000nm.

[0028] For the above scanning optical system, the embodiment of the present invention also provides a method for designing a scanning optical system, including the following steps: On the basis of the optical system body 1 for imaging or detection, a double Risley prism unit 2 for regulating the deflection of the optical axis is added. The design of the structure and parameters of the optical system body 1 belongs to the prior art and will not be elaborated here. The embodiment of the present invention mainly designs the structure and parameters of the double Risley prism unit 2. The structural model of the double Risley prism unit 2 includes a first Risley prism 21 and a second Risley prism 22. The adjacent faces of the first Risley prism 21 and the second Risley prism 22 are parallel to each other, and the first Risley prism 21 and the second Risley prism 22 rotate coaxially.

[0029] Please refer to Figure 2 , and construct an optical axis deflection model of the double Risley prism unit 2 based on the structure of the double Risley prism unit 2. And based on the vector form of Snell's law, the optical axis direction vector of the light ray after being processed by the double Risley prism unit 2 is derived. Specifically, the deflection angle of the light ray after being processed by the double Risley prism unit 2 is expressed as , and the azimuth angle of the light ray is expressed as . Let the optical axis direction vector of the incident light ray be , and the wedge angles of the first Risley prism 21 and the second Risley prism 22 are respectively and , and their corresponding rotation angles are respectively expressed as and . The distance from the front surface of the first Risley prism 21 to the scanning trajectory plane (i.e., the plane of the full field of view 3) is D.

[0030] From the wedge angles and rotation angles of the first Risley prism 21 and the second Risley prism 22, the normal vectors of the inclined surfaces of the first Risley prism 21 and the second Risley prism 22 (i.e., the front surface of the first Risley prism 21 and the rear surface of the second Risley prism 22) can be obtained as follows: ; .

[0031] represents the normal vector of the inclined surface of the first Risley prism 21, represents the normal vector of the inclined surface of the second Risley prism 22.

[0032] The vector form of Snell's law is: ; .

[0033] Among them, and are the refractive indices corresponding to the two media at both ends of the interface respectively; , are the direction vectors of the incident light ray and the refracted light ray at both ends of the interface between the two media respectively; is the interface normal vector.

[0034] According to the above vector form of Snell's law, the optical axis direction vector of the light ray emerging from the first Risley prism 21 can be derived, specifically as follows: .

[0035] Since the adjacent faces (the rear surface of the first Risley prism 21 and the front surface of the second Risley prism 22) of the double Risley prism unit 2 are parallel to each other, light rays exit from the rear surface of the first Risley prism 21 and are transmitted into the front surface of the second Risley prism 22, without changing the optical axis direction vector of the light rays. Therefore, the optical axis direction vector of the light rays exiting from the second Risley prism 22 can be obtained. , and: ; .

[0036] Therefore, the optical axis direction vector of the light rays passing through the double Risley prism unit 2 can be obtained. Further, the optical axis scanning trajectory after the relative rotation of the first Risley prism 21 and the second Risley prism 22 can be obtained. The expression of the optical axis scanning trajectory is as follows: ; .

[0037] Where, represents the rotational angular velocity of the first Risley prism 21, represents the rotational angular velocity of the second Risley prism 22, represents the initial relative angular difference between the first Risley prism 21 and the second Risley prism 22; represents the distance between the left surface of the first Risley prism 21 and the plane where the full field of view 3 is located, that is, the distance from the surface of the first Risley prism 21 close to the optical system body 1 to the scanning trajectory plane, , , represent the cosine vector coordinates of the optical axis direction of the light rays passing through the double Risley prism unit 2.

[0038] Through the expression of the optical axis scanning trajectory, the optical axis scanning trajectories of the first Risley prism 21 and the second Risley prism 22 at different rotational speed ratios can be determined. Combining with the corresponding rotation control mechanism, the optimal speed ratio for achieving full field of view scanning can be determined.

[0039] According to the field of view requirements of the scanning optical system, the materials and wedge angles of the first Risley prism 21 and the second Risley prism 22 are further designed, that is, the wedge angles , and the refractive index of the material are determined.

[0040] To solve the chromatic aberration problem in the 400nm - 1000nm wide wavelength band, both the first Risley prism 21 and the second Risley prism 22 are made of BaF 2It is glued with D-ZLAF50, and the design scheme is verified by simulation in different rotation states, specifically as follows: Please refer to Figure 3 , Figure 4 and Figure 5 , the first Risley prism 21 and the second Risley prism 22 are tested in rotation state 1, rotation state 2, and rotation state 3. Among them, the focal length of the optical system body 1 participating in the imaging (or detection) of the entire system is 61 mm.

[0041] For the detailed design parameters of the first Risley prism 21 and the second Risley prism 22, please refer to Table 1. Since both the first Risley prism 21 and the second Risley prism 22 are made of two parts of materials glued together, for the convenience of expression, the front and back surfaces of the first part BaF 2 of the first Risley prism 21 are called surface 1 and surface 2, the front and back surfaces of the second part D-ZLAF50 of the first Risley prism 21 are called surface 3 and surface 4, and surface 2 and surface 3 are glued together; similarly, the front and back surfaces of the first part D-ZLAF50 of the second Risley prism 22 are called surface 5 and surface 6, and the front and back surfaces of the second part BaF 2 of the second Risley prism 22 are called surface 7 and surface 8, and surface 6 and surface 7 are glued together.

[0042] Table 1 Detailed design parameters of the rotating Risley prism

[0043] As Figure 6 , Figure 7 and Figure 8 , the corresponding standard spot diagrams are obtained by testing in three rotation states. It can be seen from the figure that the data design in Table 1 corrects the chromatic aberration in the 400 nm - 1000 nm wide wavelength band and controls it within a reasonable range. This design can be applied to the imaging field and beam control field in the 400 nm - 1000 nm wavelength band.

[0044] To realize the design of a large field of view, wide spectral scanning optical system for space target detection, the double Risley prism unit 2 and the existing optical system body 1 are cascaded to obtain a scanning optical system, and the overall scanning optical system is tested. The design parameters of the scanning optical system are shown in Table 2.

[0045] Table 2 Design parameters of the large field of view, wide spectral scanning optical system

[0046] The scanning optical system obtained by cascading the double Risley prism unit 2 and the optical system body 1 was further tested, and verification tests were carried out for rotation state 1 (field of view 0° - 30°), rotation state 2 (field of view -15° - 15°), and rotation state 3 (field of view -30° - 0°). The specific results are as follows: In Figure 9 the rotation state 1 (field of view 0° - 30°) as shown, the standard spot diagram of the scanning optical system as shown in Figure 10 , the lateral chromatic aberration diagram of the scanning optical system as shown in Figure 11 , the encircled energy distribution diagram of the scanning optical system as shown in Figure 12 , and the relative illumination diagram of the scanning optical system as shown in Figure 13 .

[0047] In Figure 14 the rotation state 1 (field of view -15° - 15°) as shown, the standard spot diagram of the scanning optical system as shown in Figure 15 , the lateral chromatic aberration diagram of the scanning optical system as shown in Figure 16 , the encircled energy distribution diagram of the scanning optical system as shown in Figure 17 , and the relative illumination diagram of the scanning optical system as shown in Figure 18 .

[0048] As Figure 19 shown, rotation state 3 is symmetric to rotation state 1. Since the optical system body 1 is selected as a rotationally symmetric optical system, the imaging quality in rotation state 3 is the same as that in rotation state 1. At the same time, by optimizing the optical system body 1, the overall imaging quality of the cascaded scanning optical system can be further improved.

[0049] For the specific parameter design of the optical system body 1, please refer to Table 3.

[0050] Table 3 Design Parameters of the Optical System Body 1

[0051] The above test results prove that the scanning optical system designed in the embodiment of the present invention has good imaging effects in different states in the working wavelength range of 400nm - 1000nm, realizes beam control with a large field of view and a wide wavelength range, and keeps the chromatic aberration of the system within the range meeting the design requirements. The scanning optical system of the present invention can not only be applied to the imaging field and the detection field, but also be used in the beam control field corresponding to the wavelength range (400nm - 1000nm).

[0052] In summary, the above description is only the preferred embodiment of this specification and is not intended to limit the protection scope of this specification. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of this specification shall be included within the protection scope of this specification.

[0053] The system, apparatus, module or unit described in one or more of the above embodiments can be specifically implemented by a computer chip or entity, or by a product with certain functions. A typical implementation device is a computer. Specifically, the computer can be, for example, a personal computer, a laptop computer, a cellular phone, a camera phone, a smart phone, a personal digital assistant, a media player, a navigation device, an email device, a game console, a tablet computer, a wearable device, or any combination of these devices.

[0054] It should also be noted that the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, commodity or device comprising a series of elements not only includes those elements, but also includes other elements not expressly listed, or further includes elements inherent to such process, method, commodity or device. Without further limitation, an element defined by the statement "comprising one..." does not exclude the existence of additional identical elements in the process, method, commodity or device comprising the said element.

[0055] Each embodiment in this specification is described in a progressive manner, and the same or similar parts among the embodiments can be referred to each other. Each embodiment focuses on the differences from other embodiments. In particular, for the system embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the description of the method embodiment.

[0056] The specific embodiments of this specification have been described above. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps recited in the claims can be performed in a different order than in the embodiments and still achieve the desired result. Additionally, the processes depicted in the figures do not necessarily require the particular order or sequential order shown to achieve the desired result. In certain embodiments, multitasking and parallel processing are also possible or may be advantageous.

Claims

1. A scanning optical system, comprising an optical system body for imaging or detection, characterized in that: Also includes: A double Risley prism unit, which is used to adjust the deflection of the optical axis, the double Risley prism unit comprises a first Risley prism and a second Risley prism whose adjacent surfaces are parallel to each other, and the first Risley prism and the second Risley prism can rotate coaxially; The first Risley prism and the second Risley prism are both made by gluing BaF2 and D-ZLAF50 materials, and are used for achromatic aberration in the 400-1000nm band.

2. The scanning optical system according to claim 1, wherein: The wedge angles of the first Risley prism and the second Risley prism are adjustable.

3. The scanning optical system according to claim 1, wherein: The light deflection angle of the double Risley prism unit is in the range of 15° to 18°.

4. The scanning optical system according to claim 1, wherein: The front surface of the first Risley prism is BaF2, and the rear surface is D-ZLAF50; the front surface of the second Risley prism is D-ZLAF50, and the rear surface is BaF2.

5. The scanning optical system according to claim 1, wherein: The refractive index of BaF2 material is 1.47 and the Abbe number is 81.60; the refractive index of D-ZLAF50 material is 1.80 and the Abbe number is 45.

49.

6. A scanning optical system design method, characterized in that: include: A double Risley prism unit for adjusting the deflection of the optical axis is added to the optical system body for imaging or detection, wherein the double Risley prism unit comprises a first Risley prism and a second Risley prism whose adjacent surfaces are parallel to each other, and the first Risley prism and the second Risley prism can rotate coaxially; Based on the vector form of Snell's law, the optical axis direction vector of the light after being processed by the double Risley prism unit is derived, and the optical axis scanning trajectory is obtained according to the relative rotation angle between the first Risley prism and the second Risley prism; The materials and wedge angles of the first Risley prism and the second Risley prism are designed according to the field of view requirements of the scanning optical system.

7. The scanning optical system design method according to claim 6, wherein: The front surface of the first Risley prism is BaF2, and the rear surface is D-ZLAF50; the front surface of the second Risley prism is D-ZLAF50, and the rear surface is BaF2.

8. The scanning optical system design method according to claim 6, wherein: The field of view of the scanning optical system is equal to the field of view of the optical system body for imaging or detection plus twice the field of view of the double Risley prism unit.

Images