A refractive rotating mirror scanning device with adjustable scanning amplitude

Abstract

This invention discloses a refractive rotating mirror scanning device with adjustable scanning amplitude. The device includes a laser generation and angle adjustment module and a rotating mirror module. The rotating mirror module has a rotating shaft at one end connected to multiple circumferentially arranged refractive lenses via a support mechanism. The rotating shaft is driven by a motor to rotate the refractive lenses around the center of the support mechanism. The laser generation and angle adjustment module generates laser light that is incident on the refractive lenses and also adjusts the incident angle of the laser. This invention replaces the traditional reflection path with a refractive light path and combines it with a laser incident angle adjustment mechanism, allowing the scanning light to expand the coverage area in a more compact manner in space, greatly improving the adaptability of the device in miniaturized, highly integrated applications. Furthermore, since the scanning amplitude can be dynamically adjusted via electronic control, the operation process is greatly simplified, maintenance costs are reduced, and efficiency is improved.

Description

Technical Field

[0001] This utility model belongs to the field of laser scanning technology, and in particular 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 requirements for size and weight (such as portable devices or vehicle-mounted systems); and third, achieving changes in the scanning angle 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. Utility Model Content

[0006] To solve the above-mentioned technical problems, this utility model provides a refractive rotating mirror scanning device with adjustable scanning amplitude. Specifically, the technical solution is as follows:

[0007] 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.

[0008] 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.

[0009] 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.

[0010] 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.

[0011] Furthermore, the surface of the refractive lens is a continuous smooth curved surface or a non-smooth irregular surface.

[0012] 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.

[0013] 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.

[0014] Furthermore, the refractive lens includes the following design steps:

[0015] 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.

[0016] 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.

[0017] 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.

[0018] 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.

[0019] 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.

[0020] This invention's structural design effectively reduces 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 device's adaptability to 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, significantly simplifying the operation process, reducing maintenance costs, and improving efficiency. Attached Figure Description

[0021] The accompanying drawings are provided to further understand the present invention and form part of the specification. They are used together with the embodiments of the present invention to explain the present invention and do not constitute a limitation thereof.

[0022] Figure 1 This is a cross-sectional schematic diagram of a refractive rotating mirror scanning device provided in an embodiment of the present invention;

[0023] Figure 2 This is a schematic diagram of the rotating mirror module structure provided in one embodiment of the present invention;

[0024] Figure 3 yes Figure 2 An enlarged schematic diagram of part A in the middle;

[0025] Figure 4 yes Figure 2 Enlarged schematic diagram of part B in the middle;

[0026] 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.

[0027] 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

[0028] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Other embodiments obtained by those skilled in the art based on the embodiments of this utility model without creative effort are all within the protection scope of this utility model.

[0029] 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.

[0030] 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 rotation axis 1, the y-axis passes through the center of 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 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, and these refracted rays will form scanning points on the projection surface. 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 α. Emitted lasers with different emission angles can illuminate different positions of 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 scanning amplitude of the scanning curve can be adjusted by changing the laser emission angle α of the laser generation module.

[0031] Figure 1 (b) is related to 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 by the support mechanism 3 with the rotation axis as the center. The laser 5 generated by the laser generation module 4 is refracted out of the ring structure after passing through the refractive lenses.

[0032] The design process for a refractive lens can be briefly described as follows:

[0033] First, within the allowable range of the emission angle, the initial laser emission angle α0 is set, and the initial rotation angle of the rotating mirror module is 0. The vertical distance G between the laser incident point on the refracting 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 refracting 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 refracting lens at the laser incident point and emission point.

[0034] Then, while keeping the laser emission angle α0 constant, the rotating mirror module is rotated so that its rotation angle changes continuously, thereby changing the position of the laser incident point on the refracting lens. Each time the position changes, 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 emission point.

[0035] Next, the laser emission angle α is continuously changed. Each time it is changed, 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.

[0036] Since each adjustment of the emission 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.

[0037] 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 the 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, thus the lower surface contours of the eight lenses collectively form a regular octagon centered on the rotation axis. In the diagram, the laser enters the refractive lens from the side of the rotating mirror module at an exit angle α. Because the rotating mirror module continuously rotates, the laser's entry position into the lens changes continuously, resulting in a continuous laser scanning line refracted on the other side of the lens.

[0038] The contours of the upper surface 201 and lower surface 202 of the refractive lens can be described as functions of parameters (r, α, θ) using a polar coordinate-like expression, where r is the perpendicular distance from the contour point to the center of the rotation axis, and θ is the angle between the line formed by the contour point and the center of the rotation axis and the y-axis (the 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.

[0039] The contour expression of the upper surface 201 is:

[0040] r1 = r 11 (θ)r 12 (α)0≤θ≤2π / N,D1≤α≤D2

[0041] The profile expression for the lower surface 202 is:

[0042] r2=r 21 (θ)r 22 (α)0≤θ≤2π / N,D1≤α≤D2

[0043] In the above formula, N represents the number of refracting lenses, D1 and D2 constitute the allowable range of the laser emission angle, and r1 and r2 can be continuous functions or continuous functions with derivatives of more than one degree. When θ = 0, it is the origin of the polar coordinate θ, and when α = 0, it is the origin of the polar coordinate α.

[0044] As mentioned earlier, the shape of the upper surface 201 in the yz section is a circular arc with radius R centered at the axis of rotation. Because it varies with angle α, r1 can be written as follows in the yz plane:

[0045]

[0046] Equation (1) is the equation for the y-direction of the laser incident point on the upper surface 201. R(α) represents the radius of the circle on the upper surface 201. A magnified view of point A on the refractive surface is shown below. Figure 3Where h is the thickness at that location, the coordinates of the laser incident point on the xy-section are as shown in the figure:

[0047] x=G(α)tanα-L, y=-R(α) (2)

[0048] Since this embodiment is designed so that the light rays at the laser incident point are parallel to the y-axis after refraction, the law of refraction states that:

[0049]

[0050] Due to the requirement that the refracted material be parallel to the y-axis, available

[0051] sinα=(n s -1)sinβ(α) (3)

[0052] Equation (3) is the relationship between α and β, and the slope of the mirror at the laser incident point is:

[0053]

[0054]

[0055] In the above formula, K is the integration constant. To find K, substitute equation (2) into α=D1:

[0056] r1cosD1=KcosD1=G(D1) (6)

[0057] From equation (6), we can obtain

[0058]

[0059] In equation (6), G(D1) is the design value, while r1 can be obtained from equations (3), (5) and (7).

[0060] The coordinates of the point where the refracted light exits the lower surface after being refracted by the lens are:

[0061] x=G(α)tanα-L, y=-Rh(α)

[0062] Because this embodiment sets the slope of the refracted light emission point on the lower surface 202 in the xy section to 0, the lower surface is parallel to the xz section in this direction.

[0063] Next, we need to find the shape of the lower surface 202 of the lens parallel to the yz section:

[0064] r2=r 21 (θ)r 22 (α) (8)

[0065] 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 In the diagram, the dashed line representing the lower surface 2022 is the cross-section of the lower surface after rotation by an angle θ. Θ(θ) is the scanning angle after rotation by an angle θ (this is a design requirement). From the law of refraction, we can obtain:

[0066] sinφ(θ)=n s sinγ(θ)

[0067]

[0068] And by Figure 4 achievable

[0069] γ(θ)=φ(θ)-Θ(θ)

[0070] The slope on the yz section after the lens is rotated by θ is...

[0071]

[0072]

[0073] The constant term in the above equation can be derived from the condition that when θ = 0, r² = r 21 (0)r 22 We obtain (α) = R(α) + h(α).

[0074] From equation (9), we can obtain r2, which means that the shapes of the upper surface 201 and the lower surface 202 can be obtained from r1 and r2 mentioned above. In reality, if the laser spot is not a single point, the spot can be divided into many points during analysis, and the surface shape of each point can be calculated. These shapes can be used as a reference to find the optimal lens surface, or optical software can be used to optimize the analysis results.

[0075] like Figure 5 As 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.

[0076] 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.

[0077] The technical solution of this utility model has now been described in conjunction with the preferred embodiments shown in the accompanying drawings. This utility model utilizes the lens refraction surface design to change the angle at which the laser enters the refractive lens, allowing lasers with different incident angles to have different maximum scanning angles after exiting the refractive lens. This enables the scanning amplitude of the scanning head to change with the incident angle, and the configuration of this utility model also reduces the overall size of the rotating mirror scanning head.

[0078] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and not to limit it; under the concept of this utility model, 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 this utility model as described above. For the sake of brevity, they are not provided in detail; although this utility model 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 positioned 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.

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