Dynamic focusing scanning system

Abstract

The invention relates to the technical field of laser processing, and provides a dynamic focusing scanning system. The dynamic focusing scanning system comprises a dynamic focusing module, a light beam deflection module and a field lens focusing module which are sequentially arranged in the optical axis direction. The dynamic focusing module comprises a front convex lens group, a diaphragm and a rear convex lens group, the optical axis of the front convex lens group coincides with the optical axis of the rear convex lens group, and the center of the diaphragm is located on the optical axis of the front convex lens group; the front convex lens group is configured to focus the input collimated light to form a light spot, the diaphragm is located at a focus point of the front convex lens group, and the rear convex lens group is configured to expand a light beam passing through the diaphragm; the light beam deflection module is configured to deflect the light beam emitted from the rear convex lens group; the field lens focusing module is configured to focus the light beam emitted from the light beam deflection module to a focal plane. According to the invention, the diaphragm can be used for filtering the return light, so that the dynamic focusing scanning system is protected, and the damage to the dynamic focusing scanning system is reduced or avoided.

Description

Technical Field

[0001] The present application relates to the field of laser processing technology, and more specifically, to a dynamic focusing scanning system. Background Art

[0002] In the field of laser processing, dynamic focusing scanning systems are widely used because they can achieve flexible laser focusing in three-dimensional space. Dynamic focusing scanning systems are mainly divided into two categories: front focusing systems and rear focusing systems. The front focusing system mainly realizes laser scanning in three-dimensional space through the cooperation of dynamic focusing modules and XY deflection galvanometers, but it has high control requirements for the optical and mechanical structure, large differences in spot size, and limited processing accuracy, so it is mainly suitable for rough processing scenarios. The rear focusing system mainly achieves high-precision planar or quasi-three-dimensional scanning through the coordinated work of dynamic focusing modules, XY deflection galvanometers and F-theta field mirrors, and is widely used in the field of fine processing. However, when using the rear focusing system to process some materials (such as metals), the dynamic focusing scanning system may be damaged.

[0003] It should be noted that the information disclosed in the above background technology section is only used to enhance the understanding of the background of this application, and therefore may include information that does not constitute prior art known to ordinary technicians in this field. Summary of the Invention

[0004] The purpose of the embodiments of the present application is to provide a dynamic focusing scanning system, which aims to solve the technical problem in the related art that the dynamic focusing scanning system may be damaged when processing some materials (such as metals).

[0005] To achieve the above objectives, the technical solution adopted in this application is:

[0006] The present application provides a dynamic focusing scanning system, which includes a dynamic focusing module, a beam deflection module and a field lens focusing module arranged in sequence along the optical axis;

[0007] The dynamic focusing module includes a front convex lens group, an aperture and a rear convex lens group, the optical axis of the front convex lens group coincides with the optical axis of the rear convex lens group, and the center of the aperture is located on the optical axis of the front convex lens group;

[0008] The front convex lens group is configured to focus the input collimated light to form a light spot, the aperture is located at the focusing point of the front convex lens group, and the rear convex lens group is configured to expand the light beam passing through the aperture;

[0009] The beam deflection module is configured to deflect the light beam emitted from the rear convex lens group;

[0010] The field lens focusing module is configured to focus the light beam emitted from the light beam deflecting module onto a focal plane.

[0011] In one possible design, the front convex lens group includes a first lens;

[0012] The rear convex lens group includes a second lens and a third lens;

[0013] The nominal distance between the front convex lens group and the rear convex lens group is the sum of the focal lengths of the front convex lens group and the rear convex lens group, and the rear convex lens group is configured to be movable along the optical axis within a preset range;

[0014] When the rear convex lens group moves along the optical axis, the optical axis of the rear convex lens group always coincides with the optical axis of the front convex lens group.

[0015] In one possible design, the beam deflection module includes a galvanometer, which includes a first deflecting reflector and a second deflecting reflector. The first deflecting reflector and the second deflecting reflector are configured orthogonally. The first deflecting reflector is configured to deflect the light beam in the X direction, and the second deflecting reflector is configured to deflect the light beam in the Y direction.

[0016] In a possible design, the field lens focusing module includes multiple lenses, and the multiple lenses are arranged in sequence along the optical axis.

[0017] In a possible design, the field lens focusing module includes three lenses, and along the optical axis direction, the three lenses are sequentially a fourth lens, a fifth lens, and a sixth lens;

[0018] The fourth lens is a convex lens, the fifth lens is a concave lens, and the sixth lens is a convex lens.

[0019] In a possible design, the field lens focusing module includes four lenses, and along the optical axis direction, the four lenses are sequentially a fourth lens, a fifth lens, a sixth lens, and a seventh lens;

[0020] The fourth lens is a concave lens, the fifth lens is a concave lens, the sixth lens is a convex lens, and the seventh lens is a convex lens.

[0021] In a possible design, the focal length of the front convex lens group is 16.5 mm-17.0 mm, and the focal length of the rear convex lens group is 51.5 mm-52.0 mm; the preset range is -2.0 mm to 2.0 mm.

[0022] In one possible design, the first lens is a plano-convex lens or a biconvex lens;

[0023] The second lens is a biconvex lens, and the third lens is a convex-concave lens;

[0024] The light-through hole of the aperture is a circular through hole, and the maximum radius of the light-through hole is 0.1 mm-0.2 mm.

[0025] In one possible design, the total focal length of the field lens focusing module is 98 mm-102 mm, and the full field angle of the field lens focusing module is 50°.

[0026] In one possible design, the beam deflection module includes a galvanometer, a MEMS mirror, or a prism.

[0027] The beneficial effects of the dynamic focus scanning system provided by this application are mainly:

[0028] In the present application, the dynamic focusing scanning system sets an aperture between the front convex lens group and the rear convex lens group, so that the aperture can filter the forward stray light near the focused light spot. In addition, the reflected light generated by highly reflective materials (such as metal or high-reflective coating) can also be filtered, thereby protecting the dynamic focusing scanning system and reducing or avoiding damage to the dynamic focusing scanning system. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the embodiments or descriptions of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0030] Figure 1 Schematic diagram of the optical path structure of the dynamic focusing scanning system provided in an embodiment of the present application;

[0031] Figure 2 is a structural diagram of a dynamic focusing module provided in an embodiment of the present application;

[0032] Figure 3 Schematic diagram of the return light of the optical path structure in the related art;

[0033] Figure 4 Schematic diagram of the returned light of the optical path structure in the embodiment of the present application.

[0034] Description of main reference numerals:

[0035] 10. Dynamic focusing module; 12. F-theta field lens; 101. Dynamic focusing module; 102. Beam deflection module; 103. Field lens focusing module; 104. Front convex lens group; 105. Rear convex lens group; 106. Aperture; 107. First lens; 108. Second lens; 109. Third lens; 112. Fourth lens; 113. Fifth lens; 114. Sixth lens; 115. Seventh lens. DETAILED DESCRIPTION

[0036] In order to make the technical problems, technical solutions and beneficial effects to be solved by this application more clearly understood, this application is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0037] It should be noted that when an element is referred to as being “fixed on” or “disposed on” another element, it may be directly on the other element or indirectly on the other element. When an element is referred to as being “connected to” another element, it may be directly connected to the other element or indirectly connected to the other element.

[0038] It should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing this 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 cannot be understood as a limitation on this application.

[0039] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. Throughout the description of this application, "plurality" means two or more, unless otherwise specifically defined.

[0040] In order to illustrate the technical solution of the present application, a detailed description is given below with reference to specific drawings and embodiments.

[0041] Figure 3 Schematic diagram of the return light of the optical path structure in the related art, wherein: Figure 3 The XY deflection galvanometer is not shown in the figure. Figure 3As shown, in the related art, the dynamic focusing scanning system is widely used because it can achieve flexible laser focusing in three-dimensional space. The dynamic focusing scanning system is mainly divided into two categories: front focusing system and rear focusing system. The front focusing system mainly realizes laser scanning in three-dimensional space through the cooperation of the dynamic focusing module and the XY deflection galvanometer, but it has high control requirements on the optical-mechanical structure, large differences in spot size, and limited processing accuracy, so it is mainly suitable for rough processing scenarios. The rear focusing system mainly achieves high-precision planar or quasi-three-dimensional scanning through the coordinated work of the dynamic focusing module 10, the XY deflection galvanometer and the F-theta field mirror 12, and is widely used in the field of fine processing. However, during the processing process using the rear focusing system, the reflected light L generated by highly reflective materials (such as metals or high-reflective coatings) may cause damage to the dynamic focusing scanning system. The reflected light L may cause overheating, performance degradation or even permanent damage to the optical components, seriously affecting the stability and service life of the system; see Figure 3 As shown, a large amount of the returned light L still passes through the dynamic focusing module 10, so the returned light L may interfere with the normal optical path of the laser beam, causing a decrease in beam quality, a decrease in focusing accuracy or a deviation in the scanning position, affecting the processing quality.

[0042] To this end, the present application provides a dynamic focusing scanning system to solve the problems in the related art. The dynamic focusing scanning system is described in detail below with reference to the accompanying drawings.

[0043] Figure 1 Schematic diagram of the optical path structure of the dynamic focusing scanning system provided in an embodiment of the present application; Figure 2 is a structural diagram of a dynamic focusing module provided in an embodiment of the present application; Figure 4 This is a schematic diagram of the return light of the optical path structure in the embodiment of the present application, combined with Figure 1 、 Figure 2 and Figure 4As shown, in one or more embodiments, the present application provides a dynamic focusing scanning system, which is a post-focusing system, which can be applied to the field of brittle material processing, such as laser cutting, laser marking, etc. The dynamic focusing scanning system includes a dynamic focusing module 101, a beam deflection module 102 and a field lens focusing module 103, which are sequentially arranged along the optical axis. The dynamic focusing module 101 includes a front convex lens group 104, an aperture 106 and a rear convex lens group 105. The optical axis of the front convex lens group 104 coincides with the optical axis of the rear convex lens group 105, and the center of the aperture 106 is located on the optical axis of the front convex lens group 104. The front convex lens group 104 is configured to focus the input collimated light to form a light spot. The aperture 106 is located at the focal point of the front convex lens group 104, and the rear convex lens group 105 is configured to expand the light beam passing through the aperture 106. The beam deflection module 102 is configured to deflect the light beam emitted from the rear convex lens group 105. The field lens focusing module 103 is configured to focus the light beam emitted from the beam deflection module 102 to the focal plane. It should be noted that Figure 4 The beam deflection module 102 is not shown.

[0044] In the embodiment of the present application, the dynamic focusing scanning system is provided with an aperture 106 between the front convex lens group 104 and the rear convex lens group 105. In this way, the aperture 106 can filter the forward stray light near the focus spot. Figure 4 As shown, the reflected light L generated by highly reflective materials (such as metal or highly reflective coating) can also be filtered by the aperture 106. When passing through the aperture 106, most of the reflected light L is filtered, thereby protecting the dynamic focus scanning system and reducing or avoiding damage to the dynamic focus scanning system. In addition, since the reflected light L is suppressed or eliminated, it is beneficial to ensure processing quality and improve scanning accuracy.

[0045] In some embodiments, direct light is prepared to be output by a laser, and the beam deflection module 102 can deflect the light beam in two directions, for example, the light beam can be deflected in the X direction and the Y direction, thereby realizing scanning control in the XY two-dimensional plane. The field lens focusing module 103 can also eliminate the flat field aberration during the focusing process, thereby ensuring that light with different incident angles in the entire scanning area can be focused on the same focal plane, thereby improving the scanning accuracy. It should be noted that in some other possible embodiments, the dynamic focusing scanning system can also include a Faraday isolator, and the Faraday isolator is located at the front end of the dynamic focusing module 101, that is, in the direction of the optical axis, the dynamic focusing module 101 is located between the Faraday isolator and the aperture 106, which can reduce the damage of the return light L to the laser.

[0046] Combine Figure 1 and Figure 2As shown, in some embodiments, the convex lens group 104 includes a first lens 107; the first lens 107 is a plano-convex lens. The plano-convex lens can effectively converge and shape the light beam, reduce spherical aberration, and improve the focusing quality of the central area. Exemplarily, the convex side of the plano-convex lens faces the light source, that is, the convex side faces the direction of the collimated light entering the convex lens group 104, or it can be said that the convex side faces away from the aperture 106, and the flat side of the plano-convex lens faces the aperture 106. The focal length of the convex lens group 104 is 16.5mm-17.0mm. For example, the focal length of the convex lens group 104 can be 16.5mm, 16.7mm, 16.9mm or 17.0mm.

[0047] It should be noted that, in some other possible embodiments, the first lens 107 may also be a biconvex lens. In other possible embodiments, the front convex lens group 104 may further include an eighth lens, which may be a biconvex lens and located between the first lens 107 and the aperture 106. This helps to reduce damage to the laser caused by the return light L.

[0048] In some embodiments, the aperture 106 has a circular aperture. This aperture can control the propagation range of the light beam, reduce the aberration contribution of marginal light, and block off-axis return light L, scattered light, or other non-main light path light. The maximum radius of the aperture is 0.1 mm to 0.2 mm. For example, the maximum radius of the aperture can be 0.1 mm, 0.15 mm, or 0.2 mm. It should be noted that in other possible embodiments, the aperture 106 can also have an elliptical or rectangular aperture.

[0049] Combine Figure 1 and Figure 2 As shown, in some embodiments, the rear convex lens assembly 105 includes a second lens 108 and a third lens 109. Exemplarily, after the light beam passes through the aperture 106, the light beam passes through the second lens 108 and the third lens 109 in sequence. The second lens 108 is a biconvex lens, and the third lens 109 is a convex-concave lens, with the concave side of the convex-concave lens facing the second lens 108 and the convex side of the convex-concave lens facing away from the second lens 108. The second lens 108 can bring the light rays diverging from the aperture 106 closer to the optical axis, which helps control the direction of the main light rays of the image. The third lens 109 helps offset or optimize aberrations.

[0050] In some embodiments, the focal length of the rear convex lens group 105 is 51.5 mm-52.0 mm; illustratively, the focal length of the rear convex lens group 105 can be 51.5 mm, 51.7 mm, 51.9 mm or 52.0 mm.

[0051] In some embodiments, the nominal distance between the front convex lens group 104 and the rear convex lens group 105 is the sum of the focal lengths of the front convex lens group 104 and the rear convex lens group 105. The rear convex lens group 105 is configured to be movable along the optical axis within a preset range; during movement of the rear convex lens group 105 along the optical axis, the optical axis of the rear convex lens group 105 always coincides with the optical axis of the front convex lens group 104. For example, the nominal distance is a designed reference distance, and the rear convex lens group 105 can be moved along the optical axis to achieve a focusing function. The preset range is -2.0 mm to 2.0 mm, for example, the preset range can be -1.5 mm to 1.5 mm, with the positive direction along the direction of propagation of the collimated light being the positive direction and the negative direction against the direction of propagation of the collimated light being the negative direction. When the rear convex lens group 105 is at 0 mm, the distance between the front convex lens group 104 and the rear convex lens group 105 is the sum of the focal lengths of the front convex lens group 104 and the rear convex lens group 105. When the rear convex lens group 105 moves from 0 mm to 1.5 mm, it indicates that the rear convex lens group 105 moves in the positive direction. Similarly, when the rear convex lens group 105 moves from 0 mm to -1.5 mm, it indicates that the rear convex lens group 105 moves in the negative direction. It should be noted that since the rear convex lens group 105 can move within a preset range, for example, within the range of -1.5 mm to 1.5 mm, the image-side focal length of the field lens focusing module 103 can be adjusted within a range of 5 mm before and after the ideal focal length.

[0052] In some embodiments, the beam deflection module 102 includes a galvanometer, which includes a first deflection reflector and a second deflection reflector. The first deflection reflector and the second deflection reflector are arranged orthogonally. The first deflection reflector is configured to deflect the light beam in the X direction, and the second deflection reflector is configured to deflect the light beam in the Y direction. This can achieve scanning control in the XY two-dimensional plane. Exemplarily, the center point of the first deflection reflector coincides with the center of the optical axis, and the center point of the second deflection reflector coincides with the center of the optical axis. The deflection angle range of the first deflection reflector is -25° to 25°. The deflection angle range of the second deflection reflector is -25° to 25°.

[0053] It should be noted that, in some other possible implementations, the beam deflection module 102 may also include a MEMS mirror or a prism to achieve beam deflection.

[0054] In some embodiments, the field lens focusing module 103 includes multiple lenses, which are arranged in sequence along the optical axis. Exemplarily, the number of lenses in the field lens focusing module 103 can be three, four, or five.

[0055] See also Figure 1As shown, in one embodiment, the field lens focusing module 103 includes four lenses. Along the optical axis, the four lenses are, in order, a fourth lens 112, a fifth lens 113, a sixth lens 114, and a seventh lens 115. The fourth lens 112 is a concave lens, the fifth lens 113 is a concave lens, the sixth lens 114 is a convex lens, and the seventh lens 115 is a convex lens. Exemplarily, the total focal length of the field lens focusing module 103 is 98 mm to 102 mm, for example, 98 mm, 100 mm, or 102 mm. The full field of view of the field lens focusing module 103 is 50°, so the field of view of the field lens focusing module 103 ranges from -25° to 25°. The scanning range of the field lens focusing module 103 is from -35 mm to 35 mm, meaning that the scanning range in the X direction is from -35 mm to +35 mm, and the scanning range in the Y direction is from -35 mm to +35 mm.

[0056] It should be noted that, in some other possible implementations, the field lens focusing module 103 may include three lenses. Along the optical axis, the three lenses are the fourth lens 112, the fifth lens 113 and the sixth lens 114 in sequence; the fourth lens 112 is a convex lens, the fifth lens 113 is a concave lens, and the sixth lens 114 is a convex lens.

[0057] The above description is merely an optional embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present application shall be included in the scope of protection of the present application.

Claims

1. A dynamic focus scanning system, characterized in that: It includes a dynamic focusing module, a beam deflection module and a field lens focusing module which are sequentially arranged along the optical axis direction; The dynamic focusing module includes a front convex lens group, an aperture and a rear convex lens group, the optical axis of the front convex lens group coincides with the optical axis of the rear convex lens group, and the center of the aperture is located on the optical axis of the front convex lens group; The front convex lens group is configured to focus the input collimated light to form a light spot, the aperture is located at the focusing point of the front convex lens group, and the rear convex lens group is configured to expand the light beam passing through the aperture; The beam deflection module is configured to deflect the light beam emitted from the rear convex lens group; The field lens focusing module is configured to focus the light beam emitted from the light beam deflecting module onto a focal plane.

2. The dynamic focus scanning system according to claim 1, wherein: The front convex lens group includes a first lens; The rear convex lens group includes a second lens and a third lens; The nominal distance between the front convex lens group and the rear convex lens group is the sum of the focal lengths of the front convex lens group and the rear convex lens group, and the rear convex lens group is configured to be movable along the optical axis within a preset range; When the rear convex lens group moves along the optical axis, the optical axis of the rear convex lens group always coincides with the optical axis of the front convex lens group.

3. The dynamic focusing scanning system according to claim 1 or 2, wherein: The beam deflection module includes a galvanometer, which includes a first deflecting reflector and a second deflecting reflector. The first deflecting reflector and the second deflecting reflector are arranged orthogonally. The first deflecting reflector is configured to deflect the light beam in the X direction, and the second deflecting reflector is configured to deflect the light beam in the Y direction.

4. The dynamic focus scanning system according to claim 3, wherein: The field lens focusing module includes multiple lenses, and the multiple lenses are arranged in sequence along the optical axis direction.

5. The dynamic focus scanning system according to claim 4, wherein: The field lens focusing module includes three lenses, and along the optical axis direction, the three lenses are the fourth lens, the fifth lens and the sixth lens in sequence; The fourth lens is a convex lens, the fifth lens is a concave lens, and the sixth lens is a convex lens.

6. The dynamic focus scanning system according to claim 4, wherein: The field lens focusing module includes four lenses, and along the optical axis direction, the four lenses are the fourth lens, the fifth lens, the sixth lens and the seventh lens in sequence; The fourth lens is a concave lens, the fifth lens is a concave lens, the sixth lens is a convex lens, and the seventh lens is a convex lens.

7. The dynamic focus scanning system according to claim 2, wherein: The focal length of the front convex lens group is 16.5mm-17.0mm, and the focal length of the rear convex lens group is 51.5mm-52.0mm; the preset range is -2.0mm to 2.0mm.

8. The dynamic focus scanning system according to claim 2, wherein: The first lens is a plano-convex lens or a biconvex lens; The second lens is a biconvex lens, and the third lens is a convex-concave lens; The light-through hole of the aperture is a circular through hole, and the maximum radius of the light-through hole is 0.1 mm-0.2 mm.

9. The dynamic focus scanning system according to claim 6, wherein: The total focal length of the field lens focusing module is 98mm-102mm, and the full field angle of the field lens focusing module is 50°.

10. The dynamic focus scanning system according to claim 1 or 2, characterized in that: The beam deflection module includes a galvanometer mirror, a MEMS mirror or a prism.

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