Method and device for acquiring short-range large-breadth square uniform-beam laser spots
By combining a uniform beam assembly and a focusing lens with an XY two-dimensional beam spreader, the problem of uneven laser heating temperature field in the prior art is solved, and a large-format square uniform beam laser spot is achieved in the close range, meeting the demand for uniform heating.
Patent Information
- Application Number
- CN202510512463.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-23
- Publication Date
- 2025-06-24
AI Technical Summary
The existing laser heating technology is difficult to obtain large-format square uniform laser spots in close range, resulting in uneven heating temperature field and cannot meet the needs of uniform heating.
The laser beam is uniformly shaped, and combined with a focus lens and an XY two-dimensional beam spreader, the laser spot with uniform light field distribution is expanded into a two-dimensional large-format square uniform spot.
It achieves the acquisition of large-format square uniform beam laser spots within a short distance, ensures the uniformity of the heating area, and is suitable for large-format heating applications at a close distance.
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Figure CN120195889A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to a method and device for obtaining a near-range large-format square uniform laser spot, belonging to the field of laser technology. Background Art
[0002] Lasers have characteristics such as high directivity, high brightness, and high monochromaticity, and are widely used in many fields such as national defense and military, industrial processing, medical treatment, and information. The high directivity of the laser beam is one of the focuses of current laser applications, that is, the divergence angle of the laser beam is small, so as to obtain a high-brightness small spot on the surface of the target object.
[0003] Laser heating has a series of advantages such as fast heating speed, high heating temperature, and precise and controllable heating area, and has broad application prospects in industrial and scientific research such as object heating and drying. This application exactly hopes to obtain a large irradiation spot at a short distance. Existing laser heating mainly uses a laser beam to directly irradiate the object to be heated, so that the temperature of the object to be heated rises to the required temperature. Since the light field distribution of the laser beam presents a Gaussian distribution, strong in the center and weak at the edge, the heating temperature field is uneven and cannot meet the requirement of uniform heating. In some special application scenarios, such as short-distance heating and drying and material modification production lines, it is usually necessary to perform large-format heating within a distance of less than 2 meters. Under the premise of taking into account both function and efficiency, a large-format square uniform laser spot becomes the only solution. By splicing the spots, a larger-format uniform laser spot can be further obtained. Summary of the Invention
[0004] In order to solve the above problems, the present invention provides a method and device for obtaining a near-range large-format square uniform laser spot. A beam homogenizing component is used to homogenize and shape the laser beam to obtain a laser spot with a uniform light field distribution, and a focusing lens and an XY two-dimensional beam expander are combined to expand the laser spot with a uniform light field distribution into a two-dimensional large-format square uniform spot.
[0005] As shown in the attached Figure 1 ..., a method for obtaining a near-range large-format square uniform laser spot provided by the present invention has the following working process: The incident laser beam passes through the beam homogenizing component and the focusing lens to obtain a square laser spot with a uniform light field distribution near the focal plane of the focusing lens, and then passes through the XY two-dimensional beam expander to obtain a large-format square uniform spot; two sides of the square laser spot are respectively along the X direction and the Y direction, and the sizes of the aspherical cylindrical surface regions perpendicular to the ridge line direction on the X-direction and Y-direction beam expansion top surfaces in the XY two-dimensional beam expander are not less than the sizes of the spots incident on the corresponding top surfaces; the size of the large-format square uniform spot is determined by the distance from the projection surface to the XY two-dimensional beam expander and the beam expansion angle of the XY two-dimensional beam expander.
[0006] As shown in the attached Figure 1 ..., attached Figure 2 ..., attached Figure 3 ..., attachedFigure 4 and appendices Figure 5 As shown in Figure 5 , a device adopted by a method for obtaining a near-range large-format square-shaped beam-uniform laser spot includes a beam-uniform component, a focusing lens, and an XY two-dimensional beam expander; The beam-uniform component preferably adopts a beam-uniform diffraction element or a square-shaped beam-uniform optical fiber to beam-uniform and shape the incident laser beam into a spot with a uniform light field distribution in the vertical-axis cross-section; the beam-uniform diffraction element is a random phase zone plate array; the square-shaped beam-uniform optical fiber is a quartz optical fiber with a rectangular waveguide mode, a step-type refractive index distribution, and a square-shaped core; The focusing lens preferably adopts a positive lens made of quartz or K9 material to converge the light beam from the beam-uniform component onto the XY two-dimensional beam expander, and ensure that the size of the aspherical region on the two top surfaces of the XY two-dimensional beam expander perpendicular to the ridge line direction is not less than the spot size in the corresponding direction; The XY two-dimensional beam expander preferably adopts a two-dimensional Powell prism or a pair of Powell prisms to expand the incident small spot into a large square-shaped spot in the two-dimensional plane; the two-dimensional Powell prism is an optical element of a Powell prism with two top surfaces facing the incident light and ridge lines perpendicular to each other, the beam expansion angle is not less than 5°, and the size of the aspherical cylindrical region is not less than 3 mm × 5 mm; the pair of Powell prisms is composed of two Powell prisms with top surfaces facing the incident light and ridge lines perpendicular to each other, the distance between the two Powell prisms is not greater than 5 mm, the beam expansion angle is not less than 5°, and the size of the aspherical cylindrical region is not less than 3 mm × 5 mm.
[0007] Beneficial effects: The method and device for obtaining a near-range large-format square-shaped beam-uniform laser spot provided by the present invention adopt a beam-uniform component to beam-uniform and shape the incident laser beam to obtain a laser spot with a uniform light field distribution, and adopt the combination of a focusing lens and an XY two-dimensional beam expander to expand the laser spot with a uniform light field distribution into a two-dimensional large-format square-shaped uniform spot. Description of the Drawings
[0008] Figure 1 is a schematic diagram of a device for obtaining a near-range large-format square-shaped beam-uniform laser spot.
[0009] Figure 2 is a schematic diagram of a Powell prism.
[0010] Figure 3 is a schematic diagram of a pair of Powell prisms.
[0011] Figure 4 is a schematic diagram of a two-dimensional Powell prism.
[0012] Figure 5 is a three-dimensional effect diagram of a two-dimensional Powell prism. Detailed Embodiments
[0013] Embodiment 1: A method and device for obtaining a near-range large-format square-shaped beam-uniform laser spot.
[0014] As shown in the appendix Figure 1 A method for obtaining a near-range large-format square-shaped beam-uniform laser spot provided by the present invention has the following working process: The incident laser beam passes through a beam-uniform component and a focusing lens, and a square laser spot with a uniform light field distribution is obtained near the focal plane of the focusing lens. Then, after being expanded by an XY two-dimensional beam expander, a large-format square-shaped uniform spot is obtained; the two sides of the square laser spot are respectively along the X direction and the Y direction, and the sizes of the aspherical cylindrical surface regions perpendicular to the ridge line direction on the X-direction and Y-direction beam expansion top surfaces in the XY two-dimensional beam expander are not less than the sizes of the spots incident on the corresponding top surfaces; the size of the large-format square-shaped uniform spot is determined by the distance from the projection surface to the XY two-dimensional beam expander and the beam expansion angle of the XY two-dimensional beam expander.
[0015] As shown in the appendix Figure 1 and the appendix Figure 2 and the appendix Figure 3 and the appendix Figure 4 and the appendix Figure 5 A device adopted for a method for obtaining a near-range large-format square-shaped beam-uniform laser spot, the device includes a beam-uniform component, a focusing lens, and an XY two-dimensional beam expander; The beam-uniform component is a beam-uniform diffraction element or a square-shaped beam-uniform optical fiber, which reshapes the incident laser beam into a spot with a uniform light field distribution in the vertical axis cross-section; the beam-uniform diffraction element is a random phase zone plate array with an eight-step structure; the square-shaped beam-uniform optical fiber is a quartz optical fiber with a rectangular waveguide mode, a step-index distribution, and a square core, the core diameter of the optical fiber is 400μm×400μm, the numerical aperture NA of the optical fiber is 0.22, and the length of the optical fiber is 4 meters, which reshapes the incident light beam into a spot with a uniform light field distribution in the vertical axis cross-section; The focusing lens is a positive lens made of quartz or K9 material, which converges the light beam from the beam-uniform component onto the XY two-dimensional beam expander, and ensures that the sizes of the aspherical surface regions on the two top surfaces of the XY two-dimensional beam expander perpendicular to the ridge line direction are not less than the sizes of the spots in the corresponding directions; The XY two-dimensional beam expander is a two-dimensional Powell prism or a pair of Powell prisms, which is used to expand the incident square-shaped uniform small spot into a square-shaped uniform large spot in a two-dimensional plane; the two-dimensional Powell prism is an optical element of a Powell prism with two top surfaces facing the incident light and perpendicular ridge lines, the beam expansion angle is 45°, and the size of the aspherical cylindrical surface region is 3mm×6mm; the pair of Powell prisms is composed of two Powell prisms with top surfaces facing the incident light and perpendicular ridge lines, the distance between the two Powell prisms is not greater than 5mm, the beam expansion angle is 45°, and the size of the aspherical cylindrical surface region is 3mm×6mm.
[0016] Example 2: The beam homogenizing component is a beam homogenizing diffraction element, which homogenizes and shapes the incident laser beam into a spot with a uniform light field distribution in the vertical cross-section; the beam homogenizing diffraction element is a random phase zone plate array with an eight-step structure; the focusing lens is a positive lens made of quartz or K9 material, with a focal length of 50 mm; the rest is the same as in Example 1.
[0017] Example 3: The beam homogenizing component is a square beam homogenizing optical fiber, which homogenizes and shapes the incident laser beam into a square spot with a uniform light field distribution in the vertical cross-section; the square beam homogenizing optical fiber is a quartz optical fiber with a rectangular waveguide mode, a step-index distribution, and a square core, with a core diameter of 400 μm × 400 μm, a numerical aperture NA of 0.22, and a length of 4 meters; the focusing lens is a positive lens made of quartz or K9 material, with a focal length of 10 mm; the rest is the same as in Example 1.
[0018] Example 4: The XY two-dimensional beam expander is a two-dimensional Powell prism; the two-dimensional Powell prism is an optical element containing two Powell prism optical elements with their top surfaces facing the incident light and their ridge lines perpendicular to each other, with a beam expansion angle of 30° and a non-spherical cylindrical region size of 4 mm × 6 mm; the rest is the same as in Example 1.
[0019] Example 5: The XY two-dimensional beam expander is a pair of two-dimensional Powell prisms; the two-dimensional Powell prism is an optical element containing two Powell prism optical elements with their top surfaces facing the incident light and their ridge lines perpendicular to each other, with a spacing of 3 mm between the two Powell prisms, a beam expansion angle of 30°, and a non-spherical cylindrical region size of 4 mm × 6 mm; the rest is the same as in Example 1.
[0020] Finally, it should be noted that the above examples are only used to illustrate the technical solutions of the present invention and are not intended to limit them; although the present invention has been described in detail with reference to the foregoing examples, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing examples, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of each embodiment of the present invention.
Claims
1. A method for obtaining a large-format square uniform laser spot at a short distance, characterized in that The working process of the method is as follows: after the incident laser beam passes through the beam homogenizing component and the focusing lens, a square laser spot with uniform light field distribution is obtained near the focal plane of the focusing lens, and then a large-format square uniform spot is obtained after the beam is expanded by the XY two-dimensional beam expander; the two sides of the square laser spot are respectively along the X direction and the Y direction, and the size of the non-spherical cylindrical area of the top surface of the X-direction and Y-direction expansion in the XY two-dimensional beam expander that is perpendicular to the ridge direction is not less than the size of the spot incident on the corresponding top surface; the size of the large-format square uniform spot is determined by the distance from the projection surface to the XY two-dimensional beam expander and the expansion angle of the XY two-dimensional beam expander.
2. The device used in the method for obtaining a short-range large-format square uniform laser spot according to claim 1 is characterized in that The device includes a beam homogenizing assembly, a focusing lens and an XY two-dimensional beam expander; The beam homogenizing component is a beam homogenizing diffraction element or a square beam homogenizing optical fiber, which homogenizes the incident laser beam into a light spot with uniform light field distribution in the vertical axis section; the beam homogenizing diffraction element is a random phase zone plate array; the square beam homogenizing optical fiber is a quartz optical fiber with a rectangular waveguide mode, a step-type refractive index distribution, and a square core; The focusing lens is a positive lens made of quartz or K9 material, which converges the light beam from the beam homogenizing assembly onto the XY two-dimensional beam expander, and ensures that the size of the aspherical surface area on the two top surfaces of the XY two-dimensional beam expander in the direction perpendicular to the ridge line is not less than the spot size in the corresponding direction; The XY two-dimensional beam expander is a two-dimensional Powell face prism or a Powell prism pair.
3. A method for obtaining a short-range large-format square uniform laser spot as claimed in claim 1, characterized in that This method uses a focusing lens combined with an XY two-dimensional beam expander to expand a laser spot with uniform light field distribution into a two-dimensional large-format square uniform spot.
4. The device used in the method for obtaining a short-range large-format square uniform laser spot according to claim 2 is characterized in that The two-dimensional Powell face prism is a Powell face prism optical element with two top surfaces facing the incident light and ridges perpendicular to each other, a beam angle of not less than 5°, and a non-spherical cylindrical area size of not less than 3mm×5mm.
5. The device used in the method for obtaining a short-range large-format square uniform laser spot as claimed in claim 2, characterized in that The Powell prism pair is composed of two Powell prisms with their top surfaces facing the incident light and their ridges perpendicular to each other. The distance between the two Powell prisms is not greater than 5 mm, the beam angle is not less than 5°, and the size of the aspherical cylindrical area is not less than 3 mm×5 mm.