Refraction type rotating mirror scanning device with adjustable scanning amplitude

Abstract

The invention discloses a refraction type rotating mirror scanning device with an adjustable scanning amplitude. The device comprises a laser generation and angle adjustment module and a rotating mirror module, one end of a rotating shaft of the rotating mirror module is connected with a plurality of refractors which are arranged in a circumferential manner through a supporting mechanism, and the rotating shaft is driven by a motor to drive the refractors to rotate along the center of the supporting mechanism; and the laser generation and angle adjustment module is used for generating laser which enters the refraction lens and is also used for adjusting the incident angle of the laser. According to the invention, a traditional reflection path is replaced by a refraction light path, and a laser incident angle adjusting mechanism is combined, so that the scanning light can complete the expansion of a coverage area in a space in a more compact manner, and the adaptation capability of the device in a miniaturized high-integration-level application scene is greatly improved. In addition, as the change of the scanning amplitude can be dynamically adjusted in an electric control mode, the operation process is greatly simplified, the maintenance cost is reduced, and the use efficiency is improved.

Description

Technical Field

[0001] This invention belongs to the field of laser scanning technology, and particularly relates to a refractive rotating mirror scanning device with adjustable scanning amplitude. Background Technology

[0002] With the widespread application of laser technology in industrial processing, medical imaging, laser marking, 3D printing, and autonomous driving, the performance requirements of laser scanning systems continue to increase. As one of the core components, the configuration and performance of the laser scanning head directly affect the scanning speed, resolution, stability, and volume control of the overall system. Among them, the laser galvanometer scanning head has become a widely adopted structural form due to its high-precision control capabilities. However, laser galvanometers rely on highly sensitive electromagnetic control mechanisms and precision optical systems, making it difficult to balance high-frequency response and angular accuracy. Their complex structure also leads to a significant increase in manufacturing and maintenance costs. At the same time, such systems are extremely sensitive to the working environment; changes in temperature and humidity, dust interference, and mechanical vibration can all affect their long-term stability.

[0003] To improve scanning speed and structural compactness, laser rotating mirror scanning heads have emerged as another common solution. The rotating mirror achieves a wide range of beam deflection through its rotational structure, thereby increasing scanning efficiency per unit time. In high-speed scanning and large-angle coverage applications, the rotating mirror structure demonstrates strong adaptability due to its inherent mechanical advantages. However, traditional reflective rotating mirror structures often rely on multi-faceted prisms for light reflection and guidance. During high-speed rotation, abrupt changes in the reflection angle at the junctions of the various mirrors can lead to beam divergence and scattering problems, resulting in energy loss and decreased scanning accuracy. Furthermore, the strong scattering effect accumulates a large amount of heat during long-term operation, affecting not only the stability of the optical path but also requiring additional cooling devices for thermal management, thus increasing system complexity and energy consumption.

[0004] To reduce scattering issues, some technical solutions propose replacing reflective surfaces with refractive structures, attempting to achieve beam deflection through lens surface shape manipulation. These refractive rotating mirror devices have achieved some success in improving energy utilization and scattering control, and some technical literature has also proposed specific refractive surface design methods. However, existing refractive rotating mirror designs generally suffer from the following shortcomings: first, the scanning amplitude is fixed, making it difficult to adapt to the needs of laser scanning in various scenarios and with variable angles; second, the overall structure is large, making it difficult to deploy in applications with strict size and weight requirements (such as portable devices or vehicle-mounted systems); and third, achieving scanning angle changes still relies on replacing optical components or adjusting the mechanical structure, lacking flexibility and real-time adjustment capabilities.

[0005] In summary, existing laser scanning systems, regardless of whether they employ galvanometer or rotating mirror structures, face the challenge of balancing performance and structural design. In practical applications, ensuring high speed and high precision while simultaneously achieving structural compactness, low energy consumption, and dynamic adjustability of the scanning angle remains a crucial area requiring breakthroughs in the current technological field. Particularly in refractive rotating mirror scanning technology, a mature solution that achieves flexible adjustment of the scanning amplitude, a more compact structure, and stable optical path is still lacking. Summary of the Invention

[0006] To solve the above-mentioned technical problems, the present invention provides a refractive rotating mirror scanning device with adjustable scanning amplitude. Specifically, the technical solution is as follows: A refractive rotating mirror scanning device with adjustable scanning amplitude includes a laser generation and angle adjustment module and a rotating mirror module. The rotating mirror module includes a rotating shaft, one end of which is connected to a plurality of circumferentially arranged refractive lenses via a support mechanism. The other end of the rotating shaft is connected to a motor, which drives the rotating shaft to rotate the refractive lenses around the center of the support mechanism. The laser generation and angle adjustment module is located on one side of the rotating mirror module and is used to generate laser light that is incident on the refractive lenses included in the rotating mirror module, and also to adjust the incident angle of the laser light. The refractive lenses are used to refract the incident laser light to generate a laser scanning line.

[0007] Furthermore, the laser generation and angle adjustment module includes a laser generation module for generating and emitting laser light, and the laser generation module is also equipped with a pose adjustment mechanism for adjusting the pose of the laser generation module, thereby adjusting the emission position and angle of the laser light.

[0008] Preferably, the laser generation and angle adjustment module includes a laser generator for generating and emitting laser light. A reflector with angle adjustment function is provided on the laser emission path. The reflector is used to reflect the emitted laser light generated by the laser generator into the refractive lens included in the rotating mirror module.

[0009] Preferably, both the laser generator and the reflector are positioned on the central axis of the rotating mirror module, and the laser emitted by the laser generator is parallel to the central axis.

[0010] Furthermore, the surface of the refractive lens is a continuous smooth curved surface or a non-smooth irregular surface.

[0011] Preferably, the rotating mirror module includes eight refractive lenses, and the eight refractive lenses are connected end to end in a ring structure with the axis of rotation as the center.

[0012] Preferably, the eight refractive lenses are identical, and the upper surface contours of the eight refractive lenses connected end to end together form a circle with the axis of rotation as the center, and the lower surface contours of the eight refractive lenses together form a regular octagon with the axis of rotation as the center.

[0013] Furthermore, the refractive lens includes the following design steps: First, within the allowable range, the initial incident angle of the laser incident on the refractive lens and the initial rotation angle of the rotating mirror module are set. Based on the desired laser refraction position and refraction angle, the refraction path in the refractive lens is deduced by using the law of refraction, thereby determining the shape slope and thickness of the refractive lens at the laser incident point and exit point. Then, keeping the initial incident angle of the laser constant, the rotating mirror module is rotated to continuously change its rotation angle, thereby continuously changing the position of the laser incident point on the refracting lens. Each time the position is changed, the corresponding refraction path is deduced by using the law of refraction based on the desired refraction position and refraction angle, thereby determining the shape slope and thickness of the refracting lens at the corresponding laser incident and exit points. Next, the incident angle of the laser is changed. Each time it is changed, the rotating mirror module is continuously rotated. Based on the law of refraction and the desired laser refraction position and angle, the shape slope and thickness that the refraction lens should have at different positions are obtained in reverse. The shape and thickness of the entire refraction lens are discretely sampled. Finally, using the obtained discrete sampled values, the shape and thickness of the continuous and complete refractive lens are obtained through interpolation or fitting algorithms, thus completing the overall design of the refractive lens.

[0014] Compared to traditional laser galvanometer scanning heads that rely on complex electromagnetic drive systems and precision optical components, this invention, through the rational design of the curved surface features of the refractive rotating mirror lens and the introduction of a mechanism for adjusting the laser incident angle, allows the scanning system to flexibly adjust the scanning amplitude without replacing optical components, thereby effectively improving the system's versatility and adaptability. Furthermore, compared to reflective rotating mirror systems using multi-faceted prism structures, this invention avoids the scattering and energy loss problems caused by the sharp reflection of the beam at the junction of the multi-faceted mirrors during high-speed rotation, significantly improving light energy utilization and the thermal stability of the scanning process.

[0015] The structural design of this invention effectively reduces the system size while maintaining scanning accuracy and speed. By replacing the traditional reflection path with a refracted light path and combining it with a laser incident angle adjustment mechanism, the scanning light can expand the coverage area in a more compact manner in space, greatly improving the adaptability of the device in miniaturized and highly integrated applications. Furthermore, since the scanning amplitude can be dynamically adjusted electronically, frequent replacement of lenses or field lens components is unnecessary, greatly simplifying the operation process, reducing maintenance costs, and improving efficiency. Attached Figure Description

[0016] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used together with the embodiments of the invention to explain the invention and do not constitute a limitation thereof.

[0017] Figure 1 This is a cross-sectional schematic diagram of a refractive rotating mirror scanning device provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of the rotating mirror module structure provided in an embodiment of the present invention; Figure 3 yes Figure 2 An enlarged schematic diagram of part A in the middle; Figure 4 yes Figure 2 Enlarged schematic diagram of part B in the middle; Figure 5 This is a schematic diagram of a refractive rotating mirror scanning device with a reflector provided in an embodiment of the present invention.

[0018] The reference numerals in the attached figures are as follows: 1-rotation axis, 2-refracting lens, 201-upper surface, 202-lower surface, 3-support mechanism, 4-laser generating module, 5-emitting laser, 6-laser generator, 7-reflector. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, other embodiments obtained by those skilled in the art without creative effort are all within the scope of protection of the present invention.

[0020] This embodiment provides a refractive rotating mirror scanning device with adjustable scanning amplitude. The device mainly consists of a laser generating module and a rotating mirror module containing several refractive lenses. The laser generating module generates a scanning laser and directs it from one side of the rotating mirror module towards the refractive lenses within the module. The laser generating module also includes a pose adjustment mechanism to adjust its pose, thereby adjusting the emission position and angle of the scanning laser. The rotating mirror module includes a rotating shaft. One end of the shaft is connected to multiple circumferentially arranged refractive lenses via a support mechanism. The other end of the shaft is connected to a motor. Driven by the motor, the rotating shaft causes the refractive lenses to rotate around the center of the support mechanism. During the rotation of the rotating mirror module, the emitted laser from the laser generating module is incident on different refractive lenses or at different positions on the same refractive lens. Through the refraction of the lenses, a continuous laser scanning curve is formed. The scanning amplitude of the laser scanning curve can be flexibly set by adjusting the pose of the laser generating module.

[0021] For ease of understanding, Figure 1 The diagram provided is a schematic representation of the scanning device. It should be noted that this diagram is for illustrative purposes only and the actual device structure has been simplified and partially shown. Figure 1 (a) is a cross-sectional view, where the cross-section shown is the xy-plane of the spatial coordinate system, with O as the origin. The x-axis passes through the center of the rotation axis 1, the y-axis passes through the center of the refractive lens 2, and the z-axis is perpendicular to the xy-plane. The rotating mirror module actually includes multiple refractive lenses 2 (only two are shown in the figure). These multiple refractive lenses 2 are distributed in a circle via a support mechanism 3, the center of which is connected to the rotation axis 1. The emitted laser 5 generated by the laser generation module 4 is incident from the side onto the refractive lens 2 in the rotating mirror module. The vertical distance between the incident point and the laser emission point is G, and the vertical distance between the incident point and the rotation axis is R. After refraction, refracted rays are formed on the other side of the lens. These refracted rays will form scanning points on the projection surface, and a series of continuous scanning points constitute the scanning curve. The vertical distance between the laser emission point of the laser generation module and the y-axis is L, and the emission angle between the emitted laser 5 and the y-axis is θ. α Laser beams emitted at different exit angles can illuminate different positions within the refractive lens. The angle and position of the refracted light rays can be calculated using the law of refraction based on parameters such as the surface shape, material, and thickness of the refractive lens. Therefore, given a fixed design parameter for the refractive lens, the laser emission angle of the laser generation module can be adjusted. α To adjust the scanning amplitude of the scanning curve.

[0022] Figure 1 (b) is with Figure 1(a) A side view of the corresponding scanning device. In the figure, eight refractive lenses 2 are connected end to end in a ring structure with the rotation axis as the center by the support mechanism 3. The laser 5 generated by the laser generation module 4 is refracted out of the ring structure after passing through the refractive lenses.

[0023] The design process for a refractive lens can be briefly described as follows: First, set the initial laser emission angle within the allowable range of the emission angle. α 0. The initial rotation angle of the rotating mirror module is 0. At this time, the vertical distance G between the laser incident point on the refractive lens and the laser emission point on the laser generation module, as well as the vertical distance R between the laser incident point on the refractive lens and the rotation axis are obtained. Based on the desired refraction position and refraction angle, the refraction path in the lens is deduced by using the law of refraction, thereby determining the shape slope and thickness of the refractive lens at the laser incident point and emission point. Then, while maintaining the laser emission angle α With 0 unchanged, the rotating mirror module is rotated to continuously change its rotation angle, thereby continuously changing the position of the laser incident point on the refracting lens. Each time the position is changed, the refraction path is deduced by using the law of refraction based on the desired refraction position and refraction angle, thus determining the shape, slope and thickness of the refracting lens at the laser incident point and exit point. Next, the laser emission angle was continuously changed. α Each time a change is made, the rotating mirror module is continuously rotated according to the above method. Based on the law of refraction and the desired laser refraction position and angle, the shape slope and thickness that the refraction lens should have at different positions are obtained in reverse.

[0024] Since each adjustment of the exit angle or the reverse calculation of the rotating mirror yields the shape, slope and thickness that the refractive lens should have at discrete points, the continuous transformation and calculation of the above steps are equivalent to discretely modeling the shape (including the laser incident surface and the laser exit surface) and thickness of the entire refractive lens. Therefore, the shape and thickness of the continuous and complete refractive lens can be obtained through interpolation or fitting algorithms, thus completing the overall design of the refractive lens.

[0025] Figure 2 This diagram is for illustrative purposes only and represents a simplified and partial representation of the actual device structure, designed to meet specific needs. The rotating mirror module comprises a ring structure consisting of eight identical refractive lenses connected end-to-end. Figure 2The left side shows its front view (xy section), and the right side shows its side view (yz section). Each refractive lens includes an upper surface 201 (laser incident surface) and a lower surface 202 (laser exit surface). Notably, the upper surface contours of these eight refractive lenses collectively form a circle centered on the rotation axis, meaning each lens's upper surface contour is a 1 / 8 circle. The lower surface of each refractive lens is a plane with straight edges; therefore, the lower surface contours of these eight lenses collectively form a regular octagon centered on the rotation axis. In the figure, the laser is emitted at an angle... α The laser enters the refractive lens from the side of the rotating mirror module. As the rotating mirror module continues to rotate, the position of the laser entering the lens changes continuously, thus refracting a continuous laser scanning line on the other side of the lens.

[0026] The contours of the upper surface 201 and lower surface 202 of the refractive lens can be described, respectively, with respect to parameters using a method similar to polar coordinate expressions. r , α , θ The function is given by r, where r is the perpendicular distance from the contour point to the center of the rotation axis. θ The angle between the line connecting the contour point and the center of the rotation axis and the y-axis (rotation angle of the mirror). Since the refractive lens is symmetrical, the shape of the entire lens can be obtained by analyzing only half of the lens shape.

[0027] The contour expression of the upper surface 201 is:

[0028] The profile expression for the lower surface 202 is:

[0029] In the above formula N The number of refractive lenses. D 1 and D 2. This constitutes the allowable range of the laser emission angle. r 1 and r 2 can be a continuous function, or a continuous function with more than one degree of differentiation. When Time is polar coordinates The origin, Time is polar coordinates The origin.

[0030] As mentioned earlier, the shape of the upper surface 201 in the yz section is defined as a circle with the rotation axis as the center and a radius of... The arc, because it follows The angle changes, therefore in yz On a plane, it can be Written as: (1) Equation (1) is the equation for the y-direction of the laser incident point on the upper surface 201. This is represented by the radius of the circle 201 on the upper surface. A magnified view of point A on the refractive surface is shown below. Figure 3 , h The thickness at that location is shown in the figure, and the laser incident point is... xy The coordinates of the cross-section are: (2) Because this embodiment is designed so that the light rays at the laser incident point are parallel after refraction. y If the axis is oriented, then according to the law of refraction:

[0031]

[0032] Because of refraction, they are parallel y The requirements of the shaft, and ,available (3) Equation (3) is and The relationship is given by the slope of the mirror at the laser incident point: (4)

[0033] (5) In the above formula K Let be the integration constant, find . K Equation (2) can be substituted into : (6) From equation (6), we can obtain (7) In equation (6) The design value can be obtained from equations (3), (5), and (7). .

[0034] The coordinates of the point where the refracted light exits the lower surface after being refracted by the lens are: ,

[0035] Because in this embodiment, the light emission point refracted on the lower surface 202 is located at... xy The slope of the cross-section is set to 0, therefore the lower surface is parallel to the plane in this direction. xz Cross-section.

[0036] Next, we need to find the shape of the lower surface 202 of the lens parallel to the yz section: (8) Because the upper surface 201 is an arc, the laser light enters the lens directly onto the lower surface 202 without refraction on the upper surface 201, and the slope in the x-direction on the lower surface 202 is 0. A magnified view of point B on the refractive surface is shown below. Figure 4 The dotted line in the diagram represents the lower surface 2022, which has rotated. Sectional lines on the lower surface after the angle. For the transfer The scanning angle after the angle (this is a design requirement). From the law of refraction, we can obtain:

[0037]

[0038] And by Figure 4 achievable

[0039] On the yz section, the lens rotates The slope after that is

[0040]

[0041]

[0042] (9) The constant term in the above equation can be derived from when , get.

[0043] From equation (9), we can obtain That is, the shapes of the upper surface 201 and the lower surface 202 can be determined by the above. and In reality, if the laser spot is not a single point, the analysis can divide the spot into many points, calculate the surface shape of each point, and use these shapes as a reference to find the optimal lens surface. Alternatively, optical software can be used to optimize the analysis based on the results.

[0044] like Figure 5As shown, in some embodiments, to achieve the angle adjustment function of the incident laser, the aforementioned laser generating module and its configured pose adjustment mechanism are replaced with a simplified laser generator 6 and a reflector 7 with angle adjustment function set in the laser output optical path. In this case, the laser output direction of the laser generator 6 can remain parallel to the rotation axis of the rotating mirror module, and the angle of the laser incident on the rotating mirror module is controlled by adjusting the reflection angle of the reflector 7. The reflector 7 reflects the laser generated by the laser generator 6 into the refractive lens. As the angle of the reflector 7 changes, the laser enters different positions of the refractive lens, thereby changing the scanning amplitude due to the different lens profiles at different positions.

[0045] Whether it's the laser generation module and its configured pose adjustment mechanism, or the laser generator and the reflector with angle adjustment function, the laser angle illuminating the refractive lens can vary continuously or discontinuously, depending on the specific application scenario. The inner surface of the refractive lens can be a continuous smooth curved surface, or it can be designed as a non-smooth irregular surface, such as a stepped shape, according to the actual application requirements.

[0046] The technical solution of the present invention has now been described in conjunction with the preferred embodiments shown in the accompanying drawings. The present invention utilizes the lens refraction surface design to change the angle at which the laser enters the refractive lens, so that lasers with different incident angles have different maximum scanning angles after leaving the refractive lens. This allows the scanning amplitude of the scanning head to change with the incident angle, and the configuration of the present invention can also reduce the overall size of the rotating mirror scanning head.

[0047] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; under the concept of the present invention, the technical features of the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations of different aspects of the present invention as described above, which are not provided in detail for the sake of brevity; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A refractive rotating mirror scanning device with adjustable scanning amplitude, characterized in that, The system includes a laser generation and angle adjustment module and a rotating mirror module. The rotating mirror module includes a rotating shaft, one end of which is connected to a plurality of circumferentially arranged refractive lenses via a support mechanism. The other end of the rotating shaft is connected to a motor, which drives the rotating shaft to rotate the refractive lenses around the center of the support mechanism. The laser generation and angle adjustment module is located on one side of the rotating mirror module and is used to generate laser light that is incident on the refractive lenses included in the rotating mirror module. It is also used to adjust the incident angle of the laser light and the incident position on the refractive lenses. The refractive lenses are used to refract the incident laser light to generate a laser scanning line. The scanning amplitude of the laser scanning line changes with the laser incident angle and the shape of the lens at the incident position.

2. The refractive rotating mirror scanning device as described in claim 1, characterized in that, The laser generation and angle adjustment module includes a laser generation module for generating and emitting laser light, and the laser generation module is also equipped with a pose adjustment mechanism for adjusting the pose of the laser generation module, thereby adjusting the emission position and angle of the laser light.

3. The refractive rotating mirror scanning device as described in claim 1, characterized in that, The laser generation and angle adjustment module includes a laser generator for generating and emitting laser light. A reflector with angle adjustment function is provided on the laser emission path to reflect the emitted laser light generated by the laser generator into the refractive lens included in the rotating mirror module.

4. The refractive rotating mirror scanning device as described in claim 3, characterized in that, Both the laser generator and the reflector are located on the central axis of the rotating mirror module, and the laser emitted by the laser generator is parallel to the central axis.

5. The refractive rotating mirror scanning device as described in claim 1, characterized in that, The surface of the refractive lens is a continuous smooth curved surface or a non-smooth irregular surface.

6. The refractive rotating mirror scanning device as described in claim 1, characterized in that, The rotating mirror module includes eight refractive lenses, which are connected end to end in a ring structure with the axis of rotation as the center.

7. The refractive rotating mirror scanning device as described in claim 6, characterized in that, The eight refractive lenses are identical. The upper surface contours of the eight refractive lenses connected end to end together form a circle with the axis of rotation as the center, and the lower surface contours of the eight refractive lenses together form a regular octagon with the axis of rotation as the center.

8. The refractive rotating mirror scanning device according to any one of claims 1 to 6, characterized in that, The design steps of the refractive lens are as follows: First, within the allowable range, the initial incident angle of the laser incident on the refractive lens and the initial rotation angle of the rotating mirror module are set. Based on the desired laser refraction position and refraction angle, the refraction path in the refractive lens is deduced by using the law of refraction, thereby determining the shape slope and thickness of the refractive lens at the laser incident point and exit point. Then, keeping the initial incident angle of the laser constant, the rotating mirror module is rotated to continuously change its rotation angle, thereby continuously changing the position of the laser incident point on the refracting lens. Each time the position is changed, the corresponding refraction path is deduced by using the law of refraction based on the desired refraction position and refraction angle, thereby determining the shape slope and thickness of the refracting lens at the corresponding laser incident and exit points. Next, the incident angle of the laser is changed. Each time it is changed, the rotating mirror module is continuously rotated. Based on the law of refraction and the desired laser refraction position and angle, the shape slope and thickness that the refraction lens should have at different positions are obtained in reverse. The shape and thickness of the entire refraction lens are discretely sampled. Finally, using the obtained discrete sampled values, the shape and thickness of the continuous and complete refractive lens are obtained through interpolation or fitting algorithms, thus completing the overall design of the refractive lens.

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