Transmission-type laser emission and detection common-aperture optical system and method

Abstract

The invention relates to a transmission-type laser emission and detection common-aperture optical system and method, and belongs to the technical field of laser systems. Comprising an imaging detection light path and a laser emission light path which share a lens group; the imaging detection light path is composed of a focusing transmitting mirror group, a fast reflecting mirror, a spectroscope and a fine television mirror group; wherein the focusing transmitting lens group comprises a primary lens, a first secondary lens and a second secondary lens, the primary lens has positive focal power, the object side surface of the primary lens is a convex surface, and the image side surface of the primary lens is a plane; the object side surface of the first secondary mirror is a convex surface, and the image side surface of the first secondary mirror is a concave surface; the object side surface of the second secondary mirror is a concave surface, and the image side surface of the second secondary mirror is a convex surface; the fine television lens group comprises a first imaging lens, a second imaging lens, a third imaging lens, a reflector, a fourth imaging lens, an imaging cemented lens and a fifth imaging lens; the imaging detection light path and the laser emission light path share the same aperture through the spectroscope. The imaging view field is improved, the design difficulty is reduced, and the manufacturing cost is high.

Description

Technical Field

[0001] The invention belongs to the technical field of axial flow fan production and manufacturing, and in particular relates to a transmission type laser emission and detection common aperture optical system and method. Background Art

[0002] The main working mode of the laser directional transmission system is based on the common aperture optical path of laser emission and detection. The detection optical path first accurately locates the target, and then focuses the laser on the target. In order to achieve this method, the traditional design of the common aperture optical path of laser emission and detection is often used in combination with an off-axis reflective beam expansion system and a precision tracking optical path. The laser emission and detection optical paths are focused over the entire working range through an off-axis secondary mirror. However, the off-axis reflective system destroys the rotational symmetry of the system and introduces various non-rotational symmetric aberrations, which affect the final imaging field of view and imaging quality of the detection system. In addition, the off-axis reflective system is sensitive to temperature, and low thermal expansion structural materials are required for assembly. The cost of structural parts and lenses is high, which is not conducive to application in small systems.

[0003] The patent with publication number CN115373122A discloses an optical system and design method for laser emission and imaging with common aperture. The system includes a front beam expansion telescope group, a dichroic mirror and a rear imaging group. The beam expansion telescope group is an off-axis two-reflection afocal Cassegrain system. The primary mirror and the secondary mirror are both parabolic surfaces. The focal points of the two mirrors coincide and there is no intermediate image point. The imaging system is an off-axis three-reflection imaging system with folded optical path. The primary mirror, the secondary mirror and the third mirror are all free-form surfaces. A plane reflector is inserted at the intermediate image point behind the secondary mirror to fold the optical path. The system adopts a total reflection design form, is insensitive to chromatic aberration, can meet the beam expansion and wide-band imaging requirements of lasers of different wavelengths, and has considerable versatility. Both the beam expansion system and the imaging system adopt a volume compression structure. The imaging system adopts a free-form surface shape and a common aperture design. Combined with the advantages of the light weight of the reflective system, the final system has a small volume, a large field of view and good image quality, and can be used for small mobile platforms.

[0004] The optical system in the prior art has at least the following problems during use:

[0005] The imaging field of view is not large enough, and the optical path system has high requirements for the installation environment, which increases the design difficulty. Summary of the invention

[0006] The present invention provides a transmission-type laser emission and detection common aperture optical system, which can greatly improve the imaging field of view. The optical path system has high requirements on the installation environment, thereby increasing the design difficulty.

[0007] In order to achieve the above object, the present invention is implemented by the following technical solutions:

[0008] A transmission-type laser emission and detection common aperture optical system, comprising an imaging detection optical path and a laser emission optical path with a common lens group; the imaging detection optical path is composed of a focusing emission lens group, a fast reflection mirror, a beam splitter, and a precision telescope group; wherein the focusing emission lens group comprises, in order from the object side to the image side: a main mirror, a first mirror, and a second mirror: the main mirror with positive optical power has a convex object side surface and a flat image side surface; the first mirror with negative optical power has a convex object side surface and a concave image side surface; the second mirror with negative optical power has a concave object side surface and a convex image side surface; the precision telescope group comprises, in order from the object side to the image side: a first imaging lens, a second imaging lens, a third imaging lens, a reflector, a fourth imaging lens, an imaging cemented lens, and a fifth imaging lens; the common aperture of the imaging detection optical path and the laser emission optical path is achieved through the beam splitter.

[0009] Furthermore, the first imaging lens with positive optical power has a convex object side surface and a concave image side surface; the second imaging lens with positive optical power has a convex object side surface and a concave image side surface; the third imaging lens with negative optical power has a concave object side surface and a concave image side surface; the fourth imaging lens with positive optical power has a convex object side surface and a convex image side surface; the imaging cemented lens with negative optical power has a concave object side surface and a convex image side surface; the fifth imaging lens with positive optical power has a convex object side surface and a concave image side surface.

[0010] Furthermore, the focusing emitting mirror group is of Galilean type, consisting of a spherical first mirror and a second mirror and an aspherical main mirror, and has no focus inside.

[0011] Furthermore, when used as an imaging optical system, the object to be observed in the distance is transmitted from the focusing transmitting mirror group through the main mirror, the first mirror, and the second mirror, and then enters the precision television mirror group through the fast reflection mirror and the beam splitter.

[0012] Furthermore, when used as a laser emission system, the laser is reflected by the beam splitter and the fast reflection mirror in sequence, enters the focusing emission mirror group, and passes through the secondary mirror, the primary mirror, and the main mirror in sequence before being emitted.

[0013] Furthermore, the half field angle of the optical system is less than or equal to 0.21°.

[0014] Furthermore, the operating wavelength of the laser emission link is 1065nm-1070nm.

[0015] Furthermore, the imaging detection link operates at a wavelength of 798 nm to 818 nm.

[0016] A method for constructing a transmission-type laser emission and detection common aperture optical system comprises the following steps:

[0017] S1. Design a beam expander telescope group of a common aperture system, adjust the installation order and focal position of the focusing transmitting mirror group and fix them;

[0018] S2, designing an imaging detection link, adjusting the installation order and focus position in the precision television lens group and fixing them;

[0019] S3, adding the beam splitter and the fast reflection mirror between the mirror groups constructed in S1 and S2, and combining the two parts of the optical path;

[0020] S4. Calibrate the optical path obtained in S3 and optimize the installation position.

[0021] The present invention provides a transmission-type laser emission and detection common aperture optical system and method. A laser emission optical system and a detection optical system are jointly constituted by a focusing emission mirror group, a fast reflection mirror, a beam splitter, and a precision telescope group. The common aperture of the optical path is achieved by the beam splitter. By optimizing the specific lens arrangement structure in the focusing emission mirror group and the precision telescope group, the production cost and design difficulty of the optical path system are further reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0023] Figure 1 A schematic structural diagram of a transmission-type laser emission and detection common aperture optical system provided by an embodiment of the present invention;

[0024] Figure 2 A transfer modulation function diagram of a transmission-type laser emission and detection common aperture optical system at 200 m provided by an embodiment of the present invention;

[0025] Figure 3 A transfer modulation function diagram of a transmission-type laser emission and detection common aperture optical system at 300 m provided by an embodiment of the present invention;

[0026] Figure 4 A transfer modulation function diagram of a transmission-type laser emission and detection common aperture optical system at 500 m provided by an embodiment of the present invention;

[0027] Figure 5 A transfer modulation function diagram of a transmission-type laser emission and detection common aperture optical system at 1000 m provided by an embodiment of the present invention;

[0028] Figure 6A transfer modulation function diagram of a transmission-type laser emission and detection common aperture optical system at 1500 m provided by an embodiment of the present invention;

[0029] Figure 7 The energy coefficient of the front telescope group at 30m for a transmission-type laser emission and detection common aperture optical system provided by an embodiment of the present invention;

[0030] Figure 8 A diagram of the energy coefficient of a transmission-type laser emission and detection common aperture optical system at a distance of 100 m for a front telescope group provided in an embodiment of the present invention;

[0031] Fig. 9 A diagram of the energy coefficient of a transmission-type laser emission and detection common aperture optical system at a distance of 500 m for a front telescope group provided by an embodiment of the present invention;

[0032] Fig.10 A diagram of the energy coefficient of the front telescope group at 1000m for a transmission-type laser emission and detection common aperture optical system provided by an embodiment of the present invention;

[0033] Fig.11 A RMSVS wavelength diagram of a front telescope in a transmission-type laser emission and detection common aperture optical system provided by an embodiment of the present invention;

[0034] Fig.12 This is an RMSVS field of view diagram of a front telescope in a transmission-type laser emission and detection common-aperture optical system provided in an embodiment of the present invention.

[0035] In the figure:

[0036] 10-focusing transmitting mirror group; 20-fast reflex mirror; 30-beam splitter; 40-precision telescope group; 101-primary mirror; 102-first primary mirror; 103-second secondary mirror; 401-first imaging lens; 402-second imaging lens; 403-third imaging lens; 404-reflecting mirror; 405-fourth imaging lens; 406-imaging cemented mirror; 407-fifth imaging lens. DETAILED DESCRIPTION

[0037] The embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0038] In the description of the present application, it should be understood that the terms "center", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply 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 understood as a limitation on the present application.

[0039] The terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, unless otherwise specified, "plurality" means two or more.

[0040] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense, for example, it can be welding, bolt connection, or riveting; it can be fixed connection, detachable connection, or integral connection; it can be mechanical connection or electrical connection; it can be directly connected or indirectly connected through an intermediate medium, or it can be internal communication between two components. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0041] Example:

[0042] Please refer to Figure 1 As shown, this embodiment provides a transmission-type laser emission and detection common aperture optical system, including an imaging detection optical path and a laser emission optical path with a common lens group; the imaging detection optical path is composed of a focusing emission lens group 10, a fast reflection mirror 20, a beam splitter 30, and a precision telescope group 40; wherein the focusing emission lens group 10 includes, from the object side to the image side, a main mirror 101, a first primary mirror 102, and a second secondary mirror 103 in order: the main mirror 101 with positive optical power, whose object side surface is convex and the image side surface is flat; the main mirror 101 with negative optical power, whose object side surface is convex and the image side surface is flat; The first mirror 102 with a high focal power has a convex object side and a concave image side; the second mirror 103 with a negative optical focal power has a concave object side and a convex image side; the precision telescope group 40 includes, from the object side to the image side, a first imaging lens 401, a second imaging lens 402, a third imaging lens 403, a reflecting mirror 404, a fourth imaging lens 405, an imaging cemented mirror 406, and a fifth imaging lens 407; the imaging detection optical path and the laser emission optical path share a common aperture through the beam splitter 30.

[0043] In this embodiment, the focusing emission lens group 10 is a transmission type, and the precision television passes through the imaging lens, imaging lens, imaging lens, reflector 404, imaging lens, imaging double glue mirror, imaging lens in sequence, and is imaged on the precision television detector. The imaging detection optical path is responsible for receiving the target light signal. The light signal enters the optical path from the focusing emission lens group 10, is reflected at the fast reflection mirror 20, passes through the beam splitter 30, and the precision television lens group 40 converges the light signal to the focal plane of the detector; the laser emission optical path is responsible for laser focusing emission, and the laser is reflected by the beam splitter 30 into the optical path, reflected at the fast reflection mirror 20, and emitted by the focusing emission lens group 10; wherein the focusing emission lens group 10, the fast reflection mirror 20, and the beam splitter 30 are all shared by sending and receiving, and the focusing emission lens group 10 focuses on both laser emission and imaging detection. The optical system has a compact size, a large field of view, and good image quality, and can be applied to a small laser directional transmission system.

[0044] Further, in some implementations of this embodiment, Figure 1 As shown, the first imaging lens 401 with positive optical power has a convex object side surface and a concave image side surface; the second imaging lens 402 with positive optical power has a convex object side surface and a concave image side surface; the third imaging lens 403 with negative optical power has a concave object side surface and a concave image side surface; the fourth imaging lens 405 with positive optical power has a convex object side surface and a convex image side surface; the imaging cemented lens 406 with negative optical power has a concave object side surface and a convex image side surface; the fifth imaging lens 407 with positive optical power has a convex object side surface and a concave image side surface.

[0045] Further, in some implementations of this embodiment, Figure 1 As shown, the focusing emitting mirror group 10 is of Galilean type, and is composed of a spherical first mirror 102 and a second mirror 103 and an aspherical primary mirror 101, and has no focus inside.

[0046] In this embodiment, the relevant parameters of each lens of the optical lens are shown in Table 1-1:

[0047] Table 1-1 Lens surface parameters

[0048]

[0049]

[0050] Further, in some implementations of this embodiment, Figures 1 to 12 As shown in , when used as an imaging optical system, the observed object in the distance is transmitted from the focusing transmitting lens group 10 through the main mirror 101, the first mirror 102, and the second mirror 103, and then passes through the fast reflection mirror 20 and the beam splitter 30 into the precision video lens group 40.

[0051] In this embodiment, the effective focal length of the imaging detection link is 600 mm. Figures 2 to 12 The data in the study show that the improved optical system has good imaging effect and the optical quality is close to the diffraction limit.

[0052] Further, in some implementations of this embodiment, Figure 1 As shown, when used as a laser emission system, the laser is reflected by the beam splitter 30 and the fast reflection mirror 20 in sequence, then enters the focusing emission mirror group 10 and passes through the secondary mirror 103, the primary mirror 102, and the main mirror 101 in sequence before being emitted.

[0053] In this embodiment, if Figures 2 to 12 As shown in , the beam expansion ratio of the laser launch link is 4.9, the improved optical quality is close to the diffraction limit, and the quality of the optical path is improved.

[0054] Further, in some implementations of this embodiment, Figure 1 As shown, the half field angle of the optical system is less than or equal to 0.21°.

[0055] Further, in some implementations of this embodiment, Figure 1 As shown, the operating wavelength of the laser transmission link is 1065nm-1070nm.

[0056] Specifically, at this working wavelength, we get Figures 7 to 10 Plot of the circled energy coefficients for different distances shown.

[0057] Further, in some implementations of this embodiment, Figure 1 As shown, the imaging detection link operates at a wavelength of 798nm-818nm.

[0058] Specifically, at this working wavelength, we get Figures 2 to 6 Transfer modulation function diagram for different distances shown.

[0059] A method for constructing a transmission-type laser emission and detection common aperture optical system comprises the following steps:

[0060] S1. Design a beam expander telescope group of a common aperture system, adjust the installation order and focal position of the focusing transmitting mirror group 10 and fix them;

[0061] S2, design the imaging detection link, adjust the installation order and focus position in the precision television lens group 40 and fix them;

[0062] S3, adding a beam splitter 30 and a fast mirror 20 between the mirror groups constructed in S1 and S2, and combining the two parts of the optical path;

[0063] S4. Perform optical path calibration and installation position optimization on the optical path obtained in S3.

[0064] In summary, when using a transmission-type laser emission and detection common aperture optical path, the optical lens groups at both ends, namely the focusing emission lens group 10 and the precision television lens group 40, are assembled separately, and then the light path is refracted through the fast reflection mirror 20 and the beam splitter 30 to reduce the influence of the environment on the light path, thereby improving the stability of the optical path system and the imaging quality.

[0065] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope of the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A transmission type laser emission and detection common aperture optical system, comprising: An imaging detection optical path and a laser emission optical path having a common lens group, characterized in that: The imaging detection optical path and the laser emission optical path are both composed of a focusing emission mirror group (10), a fast reflection mirror (20), a beam splitter (30), and a precision telescope group (40); The focusing transmitting mirror group (10) comprises, in order from the object side to the image side: a main mirror (101), a first secondary mirror (102), and a second secondary mirror (103): The primary mirror (101) has a positive optical power, the object side surface of which is a convex surface, and the image side surface of which is a flat surface; The first submirror (102) has a negative optical power, the object side surface of which is a convex surface, and the image side surface of which is a concave surface; The secondary mirror (103) has a negative optical power, the object side surface of which is a concave surface, and the image side surface of which is a convex surface; The precision telephoto lens group (40) comprises, in order from the object side to the image side: a first imaging lens (401), a second imaging lens (402), a third imaging lens (403), a reflector (404), a fourth imaging lens (405), an imaging cemented lens (406), and a fifth imaging lens (407); The beam splitter (30) is used to realize the common aperture of the imaging detection light path and the laser emission light path.

2. A transmission type laser emission and detection common aperture optical system according to claim 1, characterized in that: The first imaging lens (401) has positive optical power, and its object side surface is convex, and its image side surface is concave; The second imaging lens (402) has positive optical power, and its object side surface is convex, and its image side surface is concave; The third imaging lens (403) has a negative optical power, and its object side surface is a concave surface, and its image side surface is a concave surface; The fourth imaging lens (405) has positive optical power, and its object side surface is convex, and its image side surface is convex; The imaging cemented lens (406) has a negative optical power, the object side surface of which is a concave surface, and the image side surface of which is a convex surface; The fifth imaging lens (407) has positive optical power, and its object side surface is convex and its image side surface is concave.

3. A transmission type laser emission and detection common aperture optical system according to claim 2, characterized in that: The focusing emitting mirror group (10) is of Galilean type, and is composed of the spherical first mirror (102) and the second mirror (103) and the aspherical primary mirror (101), and has no focus inside.

4. A transmission type laser emission and detection common aperture optical system according to claim 3, characterized in that: When used as an imaging optical system, a distant object to be observed is transmitted from the focusing transmitting mirror group (10) through the main mirror (101), the first primary mirror (102), and the second secondary mirror (103), and then passes through the fast reflection mirror (20) and the beam splitter (30) and enters the precision telescope group (40).

5. A transmission type laser emission and detection common aperture optical system according to claim 4, characterized in that: When used as a laser emission system, the laser is reflected by the beam splitter (30) and the quick-reflection mirror (20) in sequence, then enters the focusing emission mirror group (10), and passes through the secondary mirror (103), the primary mirror (102), and the primary mirror (101) in sequence, before being emitted.

6. A transmission type laser emission and detection common aperture optical system according to claim 5, characterized in that: The half field angle of the optical system is less than or equal to 0.21°.

7. A transmission type laser emission and detection common aperture optical system according to claim 6, characterized in that: The operating wavelength of the laser transmission link is 1065nm-1070nm.

8. A transmission type laser emission and detection common aperture optical system according to claim 7, characterized in that: The imaging detection link operates at a wavelength of 798nm-818nm.

9. A method for constructing a transmission-type laser emission and detection common aperture optical system as claimed in claim 8, characterized in that: The following steps are involved: S1. Design a beam expander telescope group of a common aperture system, adjust the installation order and focal position of the focusing transmitting mirror group and fix them; S2, designing an imaging detection link, adjusting the installation order and focus position in the precision television lens group and fixing them; S3, adding the beam splitter and the fast reflection mirror between the mirror groups constructed in S1 and S2, and combining the two parts of the optical path; S4. Calibrate the optical path obtained in S3 and optimize the installation position.

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