A switched illumination laser beam shaping method and system

Abstract

The present application relates to the technical field of semiconductor photoelectric, in particular to a switching type illumination laser beam shaping method and system. The method comprises: setting at least one fixed lens group, the first biconvex lens is arranged at the end of the fixed lens group away from the light source, at least one first meniscus lens is arranged between the first biconvex lens and the other end of the fixed lens group; the light beam generated by the light source is shaped into a shaped light beam after entering the fixed lens group; the variable power lens group is also arranged between the fixed lens group and the light source, the second biconvex lens is arranged at the end of the variable power lens group close to the light source, at least one second meniscus lens is arranged between the second biconvex lens and the other end of the variable power lens group; the variable power lens group is moved between the light source and the fixed lens group, the shaped light beam with changed divergence angle is obtained, and the adjustable two-grade divergence angle laser beam is realized.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of semiconductor photoelectric technology, in particular to a switching type illumination laser beam shaping method and system. BACKGROUND

[0002] Laser night vision technology belongs to one of the active night vision technologies, and its core component is an auxiliary illumination laser. The auxiliary illumination laser has the advantages of long action distance and clear imaging. The laser output by the auxiliary illumination laser is a Gaussian beam, and the spot distribution is in a Gaussian distribution. The laser intensity of the illumination laser without processing is usually uniformly distributed, and therefore it is necessary to shape the illumination laser into a flat-top beam. In security applications, when observing at a short distance, the camera lens has a small focal length and a large field of view, and the illumination laser is required to cover most or even all of the field of view. When observing at a long distance, the illumination laser is required to have sufficient brightness to meet the requirement of clear imaging of the camera, and therefore the shaping optical system is required to have a divergence angle switching function.

[0003] In view of the above requirements, the present application provides a switching type illumination laser beam shaping method and system, which realizes the shaping of the illumination laser and the two-grade divergence angle adjustable laser beam. SUMMARY

[0004] The purpose of the present application is to solve the technical problem of different laser illumination coverage ranges at different distances. The present application provides a switching type illumination laser beam shaping method and system, which realizes two-grade divergence angle adjustable laser illumination and is applied to the field of security laser active illumination and other related fields, and has great engineering application value.

[0005] In order to achieve the above-mentioned purpose of the application, the present application provides the following technical scheme:

[0006] A switching type illumination laser beam shaping method, comprising:

[0007] At least one fixed lens group is provided, and a first double convex lens is arranged at one end of the fixed lens group away from a light source. At least one first meniscus lens is arranged between the first double convex lens and the other end of the fixed lens group.

[0008] The light source generates a shaped beam after the shaped beam is injected into the fixed lens group.

[0009] A movable variable power lens group is further included between the fixed lens group and the light source. A second double convex lens is arranged at one end of the variable power lens group close to the light source. At least one second meniscus lens is arranged between the second double convex lens and the other end of the variable power lens group.

[0010] The variable power lens group is moved between the light source and the fixed lens group to obtain the shaped beam with a changed divergence angle.

[0011] As a preferred technical solution of the present application, the concave surface of the first meniscus lens faces the light source.

[0012] As a preferred technical solution of the present application, the first meniscus lens comprises at least one positive meniscus lens and at least one first negative meniscus lens.

[0013] As a preferred technical solution of the present application, the first negative meniscus lens is arranged in a direction close to the light source, and the positive meniscus lens is arranged in a direction away from the light source.

[0014] As a preferred technical solution of the present application, the radius of curvature of the convex surface of the first lenticular lens close to the light source is greater than the radius of curvature of the convex surface away from the light source.

[0015] As a preferred technical solution of the present application, the second meniscus lens comprises at least one second negative meniscus lens.

[0016] As a preferred technical solution of the present application, the convex surface of the second meniscus lens faces the light source.

[0017] As a preferred technical solution of the present application, the radius of curvature of the convex surface of the second lenticular lens close to the light source is greater than the radius of curvature of the convex surface away from the light source.

[0018] As a preferred technical solution of the present application, the mechanical half-diameter of the first meniscus lens is greater than the mechanical half-diameter of the second meniscus lens.

[0019] The present application provides a switching type illumination laser beam shaping system, comprising:

[0020] At least one fixed lens group, one end of the fixed lens group away from the light source is provided with a first lenticular lens, and at least one first meniscus lens is arranged between the first lenticular lens and the other end of the fixed lens group.

[0021] And at least one movable zoom lens group, one end of the zoom lens group close to the light source is provided with a second lenticular lens, and at least one second meniscus lens is arranged between the second lenticular lens and the other end of the zoom lens group.

[0022] The zoom lens group is located between the light source and the fixed lens group.

[0023] Compared with the prior art, the present application has the following beneficial effects:

[0024] The shaping optical method and system provided by the application utilize simple spherical lens groups to homogenize Gaussian light beams into flat-top light beams; through movable variable magnification lens groups, laser beam intensity distribution and illumination laser far-field light intensity distribution are changed, far-field laser spot uniformity is high, and active illumination effect is better; two-grade switching is adopted, the variable magnification lens groups are cut in the optical path, the divergence angle of the illumination laser is changed under the condition that the laser intensity distribution is still flat-top distribution. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 is a ray diagram of a light beam shaping system with only fixed lens groups;

[0026] Figure 2 is Figure 1 is a far-field distribution diagram of corresponding illumination laser in acquisition software;

[0027] Figure 3 is a ray diagram of a light beam shaping system after moving in the variable magnification lens groups;

[0028] Figure 4 is Figure 3 is a far-field distribution diagram of corresponding illumination laser in acquisition software; DETAILED DESCRIPTION

[0029] In order to make the purpose, technical scheme and advantages of the embodiments of the application clearer, the technical scheme in the embodiments of the application will be described clearly and completely below with reference to the drawings. Obviously, the described embodiments are part of the embodiments of the application, rather than all the embodiments.

[0030] Therefore, the following detailed description of the embodiments of the application is not intended to limit the scope of the claimed application, but merely represents some embodiments of the application. Based on the embodiments in the application, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of protection of the application.

[0031] It should be noted that the embodiments in the application and the features and technical solutions in the embodiments can be combined with each other without conflict.

[0032] It should be noted that: similar reference numerals and letters represent similar items in the following drawings, therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0033] In the description of the present application, it should be noted that the terms "upper", "lower", and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship commonly used when the product of the present application is used, or the orientation or positional relationship commonly understood by those skilled in the art. Such terms are only for the convenience of describing the present application and simplifying the description, and are not intended to indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application. In addition, the terms "first", "second", and the like are only used to distinguish the description and cannot be understood as indicating or implying relative importance.

[0034] For example Figure 1 And Figure 3 The optical path schematic diagrams of the light beam shaping system provided by the present application under different gears are shown. The light beam shaping method of the switching type illumination laser provided by the present application is used to realize the light divergence angle switching process shown in the figure, and specifically includes:

[0035] The output of the to-be-shaped light beam is realized through the semiconductor laser fiber coupling technology. In the embodiment, the fiber core diameter is 220 μm, and the numerical aperture NA is 0.22.

[0036] For example Figure 1 As shown, at least one fixed lens group 6 is arranged, and a first double convex lens 5 is arranged at the end of the fixed lens group 6 away from the light source. At least one first meniscus lens group is arranged between the first double convex lens 5 and the other end of the fixed lens group 6. The to-be-shaped light beam generated by the light source is incident into the fixed lens group 6 to obtain a shaped light beam, for example Figure 2 As shown, the divergence angle of the shaped light beam is compressed to 0.9 mrad-1.0 mrad, and the far-field spot distribution is flat.

[0037] Since the to-be-shaped light beam emitted from the fiber end face is not limited by the cladding, the light will diverge in all directions. In some embodiments, as a preferred implementation, the concave surface of the first meniscus lens group is directed towards the light source, which is beneficial to reduce the spherical aberration of the meniscus lens and improve the uniformity of the emitted light beam. The first meniscus lens group includes at least one positive meniscus lens 4 arranged in the direction away from the light source and at least one first negative meniscus lens 3 arranged in the direction close to the light source. The first negative meniscus lens 3 is used to pre-disperse the converging light beam to reduce the situation that the first double convex lens 5 generates chromatic aberration or thermal distortion due to strong converging light. The positive meniscus lens 4 compresses the diameter of the to-be-shaped light beam, reduces the size of the light beam incident into the first double convex lens 5, thereby shortening the focal length of the system, which is beneficial to reduce the length of the optical axis direction of the system.

[0038] Preferably, the radius of curvature of the convex surface of the first biconvex lens 5 near the light source is greater than the radius of curvature of the convex surface away from the light source. Light rays enter from the convex surface with the lower refractive index and gradually converge inside the lens, which helps improve the uniformity of the light spot and ultimately shapes the converging beam into a flat-top beam. In this embodiment, the far-field distribution of the beam shaped by the fixed lens group 6 is, for example... Figure 2 As shown.

[0039] It should be noted that, as those skilled in the art will understand, the sign of the radius of curvature in this application is used to indicate the convex or concave direction of the surface toward the light, and not to indicate the magnitude of the radius of curvature; with the direction of light propagation as the reference, the radius of curvature of a surface convex toward the direction of light propagation is positive, and the radius of curvature of a surface convex away from the direction of light propagation is negative. Therefore, those skilled in the art should understand that the comparison of radii of curvature in this application is based on the absolute value of the radius of curvature.

[0040] In one embodiment, as shown in Table 1, all lenses in the fixed lens group 6 are spherical lenses made of H-ZLAF75A glass. Compared with aspherical lenses for beam shaping, the lens processing is less difficult and less expensive. Specifically, the first negative meniscus lens 3 has a concave radius of curvature of -113.448, a convex radius of curvature of -299.20, a thickness of 7.2 mm, and a mechanical half-diameter of 43.043; the positive meniscus lens 4 has a concave radius of curvature of -172.288, a convex radius of curvature of -99.50, a thickness of 10.0 mm, and a mechanical half-diameter of 51.463; the first biconvex lens 5 has a convex radius of curvature of 791.410 near the light source, a convex radius of curvature of -314.228 away from the light source, a thickness of 10.0 mm, and a mechanical half-diameter of 56.025.

[0041]

[0042] A movable zoom lens group 7 is also included between the fixed lens group 6 and the light source. A second biconvex lens 1 is positioned at one end of the zoom lens group 7 near the light source to initially compress the size of the diverging beam emitted from the optical fiber. At least one second meniscus lens group is positioned between the second biconvex lens 1 and the other end of the zoom lens group 7. The zoom lens group 7 is mounted on a one-dimensional translation stage with a positioning accuracy of 5 μm. For example... Figure 3 As shown, by moving the one-dimensional translation stage downwards, the zoom lens group 7 is moved between the light source and the fixed lens group 6, resulting in a shaped beam with a changed divergence angle, for example... Figure 4 As shown, the divergence angle of the shaped beam is compressed to 1.8 mrad - 1.9 mrad, and its far-field spot distribution exhibits a flat-topped distribution. The one-dimensional translation stage moves upward, moving the zoom lens group 7 out from between the light source and the fixed lens group 6, thus reducing the divergence angle of the shaped beam. In this embodiment, the far-field distribution of the shaped beam after passing through the zoom lens group 7 and the fixed lens group 6 is shown in the following example. Figure 4as shown.

[0043] As a preferred embodiment, the second meniscus lens group comprises at least one second negative meniscus lens 2 with a convex surface facing the light source, the light beam to be shaped is incident from the side with smaller curvature and is emitted from the side with larger curvature, which makes the process of outward divergence of the light beam more uniform and increases the divergence angle of the light beam entering the fixed lens group 6, thereby realizing two-step change of the divergence angle of the shaped light beam.

[0044] Preferably, the radius of curvature of the convex surface of the second double convex lens 1 close to the light source is greater than the radius of curvature of the convex surface away from the light source, which is conducive to improving the uniformity of the light spot.

[0045] Preferably, the mechanical half-diameter of the first meniscus lens group is greater than the mechanical half-diameter of the second meniscus lens group, so that the larger the effective optical aperture of the first meniscus lens group, the larger the coverage range of the light beam; after cooperating with the fixed lens group 6, the numerical aperture of the entire system is improved, and the divergence angle of the shaped light beam is increased.

[0046] In an embodiment, for example as shown in Table 2, all lenses of the variable lens group 7 are spherical lenses made of SILICA glass, which has lower difficulty in lens processing and lower cost compared with aspherical lenses for light beam shaping. Among them, the radius of curvature of the convex surface of the second double convex lens 1 close to the light source is 233.453, the radius of curvature of the convex surface away from the light source is -25.000, the thickness is 7.0mm, and the mechanical half-diameter is 12; the radius of curvature of the concave surface of the second negative meniscus lens 2 is 84.320, the radius of curvature of the convex surface is 203.200, the thickness is 8.5mm, and the mechanical half-diameter is 20.

[0047]

[0048] The application provides a switching type illumination laser beam shaping system, for example Figure 1 as shown, comprising: at least one fixed lens group 6, the fixed lens group 6 is provided with a first double convex lens 5 at one end away from the light source, and at least one first meniscus lens group is arranged between the first double convex lens 5 and the other end of the fixed lens group 6.

[0049] and at least one movable variable lens group 7, the variable lens group 7 is provided with a second double convex lens 1 at one end close to the light source, and at least one second meniscus lens group is arranged between the second double convex lens 1 and the other end of the variable lens group 7.

[0050] The variable lens group 7 is located between the light source and the fixed lens group 6.

[0051] The above examples are only used to illustrate the technical solutions described in the present application and do not limit the present application. Although the present application has been described in detail with reference to the above examples, the present application is not limited to the above specific embodiments. Therefore, any modification or equivalent replacement of the present application; and all technical solutions and improvements without departing from the spirit and scope of the application are all included in the scope of the claims of the present application.

Claims

1. A method of switching illumination laser beam shaping, characterized by, The application relates to a light shaping device, comprising: at least one fixed lens group, wherein a first double convex lens is arranged at one end of the fixed lens group away from a light source, and a positive meniscus lens away from the light source and a first negative meniscus lens close to the light source are arranged between the first double convex lens and the other end of the fixed lens group; a shaped light beam generated by the light source is injected into the fixed lens group to obtain a flat-top distributed shaped light beam; a movable variable lens group is further arranged between the fixed lens group and the light source, wherein a second double convex lens is arranged at one end of the variable lens group close to the light source, and a second negative meniscus lens with a convex surface facing the light source is arranged between the second double convex lens and the other end of the variable lens group; the variable lens group is moved between the light source and the fixed lens group to obtain the shaped light beam with a changed divergence angle.

2. The method of claim 1, wherein, The concave surface of the first negative meniscus lens faces the light source.

3. The method of claim 1, wherein, The first negative meniscus lens is arranged in a direction close to the light source, and the positive meniscus lens is arranged in a direction away from the light source.

4. The shaping method according to any one of claims 1 to 2, characterized in that, The radius of curvature of the convex surface of the first double convex lens close to the light source is greater than the radius of curvature of the convex surface away from the light source.

5. The method of claim 1, wherein, The convex surface of the second negative meniscus lens faces the light source.

6. The method of claim 1, wherein, The radius of curvature of the convex surface of the second double convex lens close to the light source is greater than the radius of curvature of the convex surface away from the light source.

7. The method of claim 1, wherein, The mechanical half-diameter of the first negative meniscus lens is greater than the mechanical half-diameter of the second negative meniscus lens.

8. A switched illumination laser beam shaping system, characterized by, The application relates to a light shaping device, comprising: at least one fixed lens group, wherein a first double convex lens is arranged at one end of the fixed lens group away from a light source, and a positive meniscus lens away from the light source and a first negative meniscus lens close to the light source are arranged between the first double convex lens and the other end of the fixed lens group; and at least one movable variable lens group, wherein a second double convex lens is arranged at one end of the variable lens group close to the light source, and a second negative meniscus lens with a convex surface facing the light source is arranged between the second double convex lens and the other end of the variable lens group; the variable lens group is arranged between the light source and the fixed lens group.

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