A laser beam shaping device with long working distance

Abstract

The present invention discloses a laser beam shaping device with a long working distance, comprising a first aspheric lens and a second aspheric lens arranged in sequence along the incident direction of the light; along the incident direction of the light, the two surfaces of the first aspheric lens are the first curved surface and the second curved surface in sequence, and the two surfaces of the second aspheric lens are the third curved surface and the fourth curved surface in sequence, wherein the first curved surface is a plane, the second curved surface is an aspheric surface, the third curved surface is an aspheric surface, and the fourth curved surface is a plane. In the shaping device of the present invention, within the range of 200-600mm, the energy distribution of the flat-top light does not change significantly, so that the user does not need to precisely control the position of the workpiece to be processed when using the product, and the workpiece can be processed with flat light as long as it is within the nominal range, which greatly shortens the adjustment time; secondly, due to the long working distance, a shaper can be adapted to multiple different specifications of equipment from multiple manufacturers, which can greatly reduce or eliminate the customization cost caused by personalized equipment from different manufacturers.

Description

Technical Field

[0001] The invention relates to a laser beam shaping device with a long working distance, belonging to the field of beam shaping devices. Background Art

[0002] Laser processing uses the energy of light to reach a high energy density at the focal point after being focused by a lens, and relies on the photothermal effect for processing. Laser processing has the advantages of good processing quality, fast processing speed, small surface deformation, and low post-processing cost, and can process a variety of materials.

[0003] At present, the laser processing industry has increasingly strict control over thermal effects, and thus has increasingly strict requirements for the distribution of laser light energy, requiring the distribution of light energy on the processing surface to change from the original Gaussian distribution to a uniform (flat-top) distribution. Common beam shaping can ensure that the light energy distribution is a flat-top distribution within a relatively small depth (about 1-10mm). If it exceeds the range, the energy distribution will be deformed and cannot meet the required processing requirements. Summary of the invention

[0004] The present invention provides a laser beam shaping device with a long working distance, which improves the problem of small working range of common beam shapers, ensures that within the range of 200-600mm, the flat-top light energy distribution does not change significantly, and can meet the processing needs of customers.

[0005] In order to solve the above technical problems, the technical solutions adopted by the present invention are as follows:

[0006] A laser beam shaping device with a long working distance comprises a first aspheric lens and a second aspheric lens which are sequentially arranged along a light incident direction; along the light incident direction, two surfaces of the first aspheric lens are sequentially a first curved surface and a second curved surface, and two surfaces of the second aspheric lens are sequentially a third curved surface and a fourth curved surface, wherein the first curved surface is a plane, the second curved surface is an aspheric surface, the third curved surface is an aspheric surface, and the fourth curved surface is a plane.

[0007] The applicant has found through research that the shaping device with the above-mentioned specific structure can ensure that the flat-top light energy distribution does not change significantly within the range of 200-600mm, and can meet the processing needs of customers.

[0008] In order to further ensure the shaping effect, preferably, the curvature radius of the first curved surface is infinite, the curvature radius of the second curved surface is -31.085±0.2 mm, the curvature radius of the third curved surface is 36.272±0.2 mm, and the curvature radius of the fourth curved surface is infinite.

[0009] In order to further improve the shaping effect, the center thickness of the first aspheric lens is 5±0.05 mm, and the center thickness of the second aspheric lens is 5±0.05 mm.

[0010] In order to achieve beam shaping at a long working distance, preferably, the center distance between the first aspheric lens and the second aspheric lens is 150±0.2 mm.

[0011] The materials used for the first aspheric lens and the second aspheric lens are both optical fused quartz.

[0012] The above working wavelength is 1064nm.

[0013] The aspheric equations used by the first aspheric lens and the second aspheric lens are both:

[0014]

[0015] Among them, z is the vector height in the direction of the optical axis; c is the curvature (the inverse of the radius of curvature); k is the cone coefficient; r is the mirror coordinate of the coordinate axis, which satisfies r in the xy coordinate system. 2 =x 2 +y 2 ; a 1 , a 2 , a 3 , a 4 It is a dimensionless coefficient of a higher order term. It has no meaning alone.

[0016] The above-mentioned long working distance laser beam shaping device is used to change the energy distribution of the laser beam. Two aspheric lenses are used to shape the Gaussian beam. The uneven Gaussian light is changed by designing the corresponding uneven aspheric surface to change the propagation path of the beam, so that the energy at one end of the output shaper is evenly distributed. Then, the divergence angle of the output beam is corrected to ensure that the light energy in the range of 200-600mm does not change too much, thereby realizing long working distance beam shaping.

[0017] The technologies not mentioned in the present invention are all referred to the prior art.

[0018] The laser beam shaping device with a long working distance of the present invention has no obvious change in the energy distribution of the flat-top light within the range of 200-600mm, so that the user does not need to precisely control the position of the workpiece to be processed when using the product. As long as it is within the nominal range, the workpiece can be processed with flat light, which greatly shortens the adjustment time. Secondly, due to the long working distance, a shaper can be adapted to multiple different specifications of equipment from multiple manufacturers, which can greatly reduce or eliminate the customization cost caused by personalized equipment from different manufacturers. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a light path diagram of a laser beam shaping device with a long working distance in an embodiment;

[0020] Figure 2The energy distribution of the laser beam before shaping in the embodiment;

[0021] Figure 3 The energy distribution of the laser beam in the embodiment after being shaped by the long working distance laser beam shaping device of the present invention;

[0022] Figure 4 This is a rendering of the embodiment without adding a shaping device;

[0023] Figure 5 This is a diagram showing the effect of adding a long working distance laser beam shaping device of the present invention to an embodiment;

[0024] In the figure, 1 is a first aspheric lens, and 2 is a second aspheric lens. DETAILED DESCRIPTION

[0025] In order to better understand the present invention, the content of the present invention is further explained below in conjunction with the embodiments, but the content of the present invention is not limited to the following embodiments.

[0026] Example 1

[0027] like Figure 1 The long working distance laser beam shaping device shown includes a first aspheric lens and a second aspheric lens arranged in sequence along the incident direction of the light; along the incident direction of the light, the two surfaces of the first aspheric lens are the first curved surface and the second curved surface in sequence, and the two surfaces of the second aspheric lens are the third curved surface and the fourth curved surface in sequence, wherein the first curved surface is a plane, the second curved surface is an aspheric surface, the third curved surface is an aspheric surface, and the fourth curved surface is a plane.

[0028] The radius of curvature of the first curved surface is infinite, the radius of curvature of the second curved surface is -31.085mm, the radius of curvature of the third curved surface is 36.272mm, and the radius of curvature of the fourth curved surface is infinite; the center thickness of the first aspheric lens is 5mm, and the center thickness of the second aspheric lens is 5mm; the center distance between the first aspheric lens and the second aspheric lens is 150mm. The materials used for the first aspheric lens and the second aspheric lens are both optical fused quartz. The above optical system is installed in a 6061 aluminum lens holder.

[0029] The second and third curved surfaces are both aspherical surfaces, and the aspherical surface equations used are:

[0030]

[0031] Among them, z is the vector height in the direction of the optical axis; c is the curvature (the inverse of the radius of curvature); k is the cone coefficient; r is the mirror coordinate of the coordinate axis, which satisfies r in the xy coordinate system. 2 =x 2 +y 2 ; a 1 , a2 , a 3 , a 4 It is the coefficient of the higher-order term, dimensionless, and has no meaning alone.

[0032] Table 1 Lens parameters:

[0033]

[0034] The wavelength of the long working distance laser beam shaping device is 1064nm, and the incident Gaussian beam is 6mm (such as Figure 2 ), the output flat top beam is 10mm (such as Figure 3 ), the working distance can be within the range of 200-600mm. On the optical rail, the laser first passes through the beam expander to convert the Gaussian beam into a 6mm beam, then passes through the above-mentioned shaper, and finally uses the test board to receive the laser to check the effect, such as Figure 4-5 As shown, within the range of 200-600mm, the flat-top light energy distribution does not change significantly, which can meet the processing needs of customers.

Claims

1. A laser beam shaping device with a long working distance, characterized in that: It comprises a first aspheric lens and a second aspheric lens which are sequentially arranged along the incident direction of light; along the incident direction of light, two surfaces of the first aspheric lens are sequentially a first curved surface and a second curved surface, and two surfaces of the second aspheric lens are sequentially a third curved surface and a fourth curved surface, wherein the first curved surface is a plane, the second curved surface is an aspheric surface, the third curved surface is an aspheric surface, and the fourth curved surface is a plane; The radius of curvature of the first curved surface is infinite, the radius of curvature of the second curved surface is -31.085 mm, the radius of curvature of the third curved surface is 36.272 mm, and the radius of curvature of the fourth curved surface is infinite; The center thickness of the first aspheric lens is 5 mm, and the center thickness of the second aspheric lens is 5 mm; the center distance between the first aspheric lens and the second aspheric lens is 150 mm; The first aspheric lens and the second aspheric lens are made of optical fused quartz; the long working distance laser beam shaping device is installed in a 6061 aluminum lens holder; The second and third curved surfaces are both aspherical surfaces, and the aspherical surface equations used are: Among them, z is the vector height in the direction of the optical axis; c is the curvature (the inverse of the radius of curvature); k is the cone coefficient; r is the mirror coordinate of the coordinate axis, which satisfies r in the xy coordinate system. 2 =x 2 +y 2 ; a1, a2, a3, a4 are high-order coefficients, dimensionless, and meaningless alone; The values ​​of the cone coefficient k and the higher-order coefficients a1, a2, a3 and a4 of the first aspheric lens and the second aspheric lens are as follows: The operating wavelength of the long working distance laser beam shaping device is 1064nm.

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