Optical lens and laser processing system

Abstract

The embodiment of the utility model provides an optical lens and a laser processing system. The optical lens sequentially comprises a first lens, a second lens, a third lens, a fourth lens, a fifth lens and a sixth lens in the laser incidence direction, the first lens is a meniscus lens, the convex surface direction is consistent with the laser incidence direction, and the first lens has positive focal power; the second lens is a biconcave lens and has negative focal power; the third lens is a meniscus lens, the convex surface direction is consistent with the laser incident direction, and the third lens has positive focal power; the fourth lens is a meniscus lens, the convex surface direction is consistent with the laser incident direction, and the fourth lens has positive focal power; the fifth lens is a biconvex lens and has positive focal power; the sixth lens is a protection flat plate.

Description

TECHNICAL FIELD

[0001] The present specification relates to the field of optics, and in particular, to an optical lens and a laser processing system. BACKGROUND

[0002] Optical lenses play an important role in applications such as scanning marking, punching, etc. Optical lenses in the ultraviolet band have better effects in punching and edge cutting due to their shorter wavelength and higher energy. However, the dispersion of the ultraviolet band lens is more serious and difficult to control. In industrial applications, due to the inherent characteristics of the ultraviolet band, when the large-angle incident light spot is compressed to the size of use, the field curvature, distortion, and telecentricity in the image plane are difficult to control.

[0003] Therefore, it is necessary to provide an optical lens capable of effectively controlling the dispersion problem of the ultraviolet band lens and having low field curvature, low distortion, and high modulation transfer function. CONTENT OF THE INVENTION

[0004] One or more embodiments of the present specification provide an optical lens, which comprises, in order along a laser incident direction: a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens. The first lens is a meniscus lens with a convex surface direction consistent with the laser incident direction, and the first lens has a positive focal power. The second lens is a double-concave lens, and the second lens has a negative focal power. The third lens is a meniscus lens with a convex surface direction consistent with the laser incident direction, and the third lens has a positive focal power. The fourth lens is a meniscus lens with a convex surface direction consistent with the laser incident direction, and the fourth lens has a positive focal power. The fifth lens is a double-convex lens, and the fifth lens has a positive focal power. The sixth lens is a protective flat plate.

[0005] In some embodiments, a first curvature radius of the first lens is in a range of (-75) to (-65) mm, and a second curvature radius of the first lens is in a range of (-45) to (-35) mm. A third curvature radius of the second lens is in a range of (-35) to (-20) mm, and a fourth curvature radius of the second lens is in a range of 350 to 450 mm. A fifth curvature radius of the third lens is in a range of (-70) to (-60) mm, and a sixth curvature radius of the third lens is in a range of (-50) to (-40) mm. A seventh curvature radius of the fourth lens is in a range of (-1390) to (-1360) mm, and an eighth curvature radius of the fourth lens is in a range of (-60) to (-40) mm. A ninth curvature radius of the fifth lens is in a range of 155 to 175 mm, and a tenth curvature radius of the fifth lens is in a range of (-265) to (-245) mm.

[0006] In some embodiments, the first lens has a center thickness in the range of 2-4 mm, the second lens has a center thickness in the range of 7-9 mm, the third lens has a center thickness in the range of 7.5-10 mm, the fourth lens has a center thickness in the range of 20-25 mm, and the fifth lens has a center thickness in the range of 19-24 mm.

[0007] In some embodiments, the first lens has an outer diameter in the range of 28-35 mm, the second lens has an outer diameter in the range of 45-50 mm, the third lens has an outer diameter in the range of 58-65 mm, the fourth lens has an outer diameter in the range of 78-85 mm, the fifth lens has an outer diameter in the range of 88-95 mm, and the sixth lens has an outer diameter in the range of 88-95 mm.

[0008] In some embodiments, the first lens has a focal length to focal length of the optical lens ratio in the range of 1.6-1.8, the second lens has a focal length to focal length of the optical lens ratio in the range of (-0.4)-(-0.3), the third lens has a focal length to focal length of the optical lens ratio in the range of 2.4-2.6, the fourth lens has a focal length to focal length of the optical lens ratio in the range of 0.9-1.1, and the fifth lens has a focal length to focal length of the optical lens ratio in the range of 1.9-2.

[0009] In some embodiments, the first lens has a refractive index to Abbe number ratio in the range of 0.019-0.023, the second lens has a refractive index to Abbe number ratio in the range of 0.031-0.035, the third lens has a refractive index to Abbe number ratio in the range of 0.019-0.023, the fourth lens has a refractive index to Abbe number ratio in the range of 0.019-0.023, the fifth lens has a refractive index to Abbe number ratio in the range of 0.019-0.023, and the sixth lens has a refractive index to Abbe number ratio in the range of 0.019-0.023.

[0010] In some embodiments, the first lens has a center to center distance to the second lens in the range of 10-15 mm, the second lens has a center to center distance to the third lens in the range of 5-10 mm, the third lens has a center to center distance to the fourth lens in the range of 1-3 mm, the fourth lens has a center to center distance to the fifth lens in the range of 2-4 mm, and the fifth lens has a center to center distance to the sixth lens in the range of 3-7 mm.

[0011] In some embodiments, the maximum distortion of the optical lens is less than or equal to 1%, the modulation transfer function (MTF) of the optical lens is greater than or equal to 145@0.3, and the image-side telecentricity of the optical lens is less than 0.9°.

[0012] In some embodiments, the field curvature of the optical lens is less than or equal to 0.07 mm, the scan angle of the optical lens is 18.6°, the scan field of the optical lens is 50 mm x 50 mm, and the working distance of the optical lens is in the range of 140-150 mm.

[0013] One or more embodiments of the present specification provide a laser processing system, comprising a laser, a scan galvanometer, and an optical lens for laser processing, the optical lens being the optical lens according to any one of the embodiments, and the center wavelength of the laser being 343 nm. BRIEF DESCRIPTION OF DRAWINGS

[0014] The present specification will be further described in the manner of exemplary embodiments, which will be described in detail with reference to the accompanying drawings. These embodiments are not limiting, and in these embodiments, the same reference numbers represent the same structures, wherein:

[0015] Figure 1 is a structural schematic diagram of an optical lens according to some embodiments of the present specification;

[0016] Figure 2 is a light path schematic diagram of an optical lens according to some embodiments of the present specification;

[0017] Figure 3 is a field curvature diagram of an optical lens according to some embodiments of the present specification;

[0018] Figure 4 is an aberration analysis diagram of an optical lens according to some embodiments of the present specification;

[0019] Figure 5 is a field curvature MTF diagram of an optical lens according to some embodiments of the present specification. DETAILED DESCRIPTION

[0020] In order to more clearly illustrate the technical solutions of the embodiments of the present specification, the drawings required to be used in the embodiment description will be briefly introduced below. Obviously, the drawings in the following description are only some examples or embodiments of the present specification, and for those skilled in the art, the present specification can also be applied to other similar scenarios without creative labor. Unless it is obvious from the language environment or otherwise stated, the same reference numbers in the drawings represent the same structures or operations.

[0021] It should be understood that the terms “system,” “device,” “unit,” and / or “module” as used herein are merely different mechanisms by which different components, elements, parts, sections, or assemblies are implemented at different levels of abstraction. However, the terms can be replaced by other expressions if other words can achieve the same purpose.

[0022] As indicated in the specification and claims herein, unless the context clearly indicates otherwise, the words “a,” “an,” “the,” and / or “this” are not limited in scope to the singular, but include the plural. Generally, the terms “include,” “including,” and / or “comprising” are intended to be inclusive, and thus there can be other steps, elements, parts, sections, or assemblies not specifically mentioned.

[0023] Figure 1 is a structural schematic diagram of an optical lens according to some embodiments of the present specification.

[0024] Some embodiments of the present specification provide an optical lens. In some embodiments, as shown in Figure 1 from the laser incidence direction, the optical lens comprises, in sequence, a first lens 1, a second lens 2, a third lens 3, a fourth lens 4, a fifth lens 5, and a sixth lens 6.

[0025] In some embodiments, the first lens 1 is a meniscus lens. In some embodiments, along the laser incidence direction, one side of the first lens 1 is a convex surface, and the direction of the convex surface is consistent with the laser incidence direction, that is, the convex surface protrudes towards the laser incidence direction; the other side is a concave surface, and the concave surface is recessed towards the inside of the first lens 1.

[0026] Focal power represents the refractive ability of an optical system to an incident parallel light beam. The greater the value of the focal power, the more the parallel light beam is folded. When the focal power is greater than 0, it means that the incident parallel light beam is convergent when it is emitted; when the focal power is less than 0, it means that the incident parallel light beam is divergent when it is emitted; when the focal power is equal to 0, it means that the incident parallel light beam is still parallel when it is emitted.

[0027] In some embodiments, the first lens 1 has positive focal power, that is, the focal power of the first lens 1 is greater than 0, which means that the parallel light beam incident to the first lens 1 is convergent when it is emitted from the first lens 1.

[0028] By setting the first lens as a meniscus lens, the convex surface of which has a convergent effect, the aperture of the incident light beam can be initially reduced, and by setting the first lens to have positive focal power, the convergent effect is further enhanced, which helps to control the size of the light beam in the subsequent optical path.

[0029] In some embodiments, the second lens 2 is a biconcave lens, with a central thickness smaller than an edge thickness. In some embodiments, both sides of the second lens 2 are concave, i.e. both sides of the second lens 2 are recessed towards the interior of the second lens 2.

[0030] In some embodiments, the second lens 2 has a negative optical power, i.e. the optical power of the second lens 2 is smaller than 0, which means that a parallel light beam incident on the second lens 2 is divergent upon exiting the second lens 2.

[0031] By setting the second lens to have a negative optical power, it has a divergent effect, which can increase the range of light entering the lens. The use of a second lens with a negative optical power after a first lens with a positive optical power helps to correct chromatic aberration, especially in the ultraviolet band, and has a better effect on chromatic aberration correction.

[0032] In some embodiments, the third lens 3 is a meniscus lens with a convex side in the same direction as the laser incident direction, and the third lens 3 has a positive optical power. The third lens 3 has similar characteristics to the first lens 1 and will not be described again.

[0033] Through the convergent effect of the third lens, the aperture of the exiting light beam can be further controlled; the third lens, together with the first lens and the second lens, forms a positive optical power-negative optical power-positive optical power structure, which is conducive to beam shaping.

[0034] In some embodiments, the fourth lens 4 is a meniscus lens with a convex side in the same direction as the laser incident direction, and the fourth lens 4 has a positive optical power. The fourth lens 4 has similar characteristics to the first lens 1 and will not be described again.

[0035] Both the third lens and the fourth lens are lenses with positive optical power, which can further converge light, making the light entering the subsequent lens more gentle. The combination of multiple lenses with positive optical power is conducive to reducing the beam aperture.

[0036] In some embodiments, the fifth lens 5 is a biconvex lens, with a central thickness greater than an edge thickness. In some embodiments, both sides of the fifth lens 5 are convex, i.e. both sides of the fifth lens 5 are convex towards the exterior of the fifth lens 5.

[0037] In some embodiments, the fifth lens 5 has a positive optical power, i.e. the optical power of the fifth lens 5 is greater than 0, which means that a parallel light beam incident on the fifth lens 5 is convergent upon exiting the fifth lens 5.

[0038] By setting the fifth lens to be a biconvex lens, a strong convergent effect can be provided, which is conducive to final imaging. The fifth lens with positive optical power can further converge light, which is conducive to improving the convergence ability of the edge field of view and improving the relative luminance of the edge field of view.

[0039] In some embodiments, the sixth lens 6 is a protective flat. In some embodiments, the sixth lens 6 can be a flat lens, i.e., both surfaces of the sixth lens 6 are flat along the laser incident direction.

[0040] The sixth lens can serve as a sealing window to maintain the internal environment of the optical system. By providing the sixth lens, the subsequent optical elements or detectors can be protected from environmental pollution and mechanical damage. In addition, by providing a flat lens, additional optical thickness can be provided without changing the optical path, which helps to fine-tune the focal length and image plane position.

[0041] In some embodiments, each lens can be made of fused quartz, calcium fluoride, magnesium fluoride, silicon, germanium, zinc selenide, various optical colorless glasses, etc. After the production of each lens is completed, it can be coated according to needs through a vacuum coating process. For example, an anti-reflection coating is coated on the surface of the lens to reduce the reflection of the lens surface, thereby reducing the loss of light energy and making the image clearer.

[0042] The radius of curvature is used to describe the degree of change in the curvature of a curve. The radius of curvature is the inverse of the curvature.

[0043] In some embodiments, the first radius of curvature of the first lens 1 is in the range of (-75) to (-65) mm, and the second radius of curvature of the first lens 1 is in the range of (-45) to (-35) mm. In some embodiments, the first radius of curvature of the first lens 1 is in the range of (-72) to (-68) mm, and the second radius of curvature of the first lens 1 is in the range of (-42) to (-38) mm. In some embodiments, the first radius of curvature of the first lens 1 is in the range of (-71) to (-70) mm, and the second radius of curvature of the first lens 1 is in the range of (-41) to (-40) mm. In some embodiments, the first radius of curvature of the first lens 1 is in the range of (-70.28) to (-70.26) mm, and the second radius of curvature of the first lens 1 is in the range of (-39.09) to (-39.07) mm. In some embodiments, the first radius of curvature of the first lens 1 is (-70.27 ± 0.01) mm, and the second radius of curvature of the first lens 1 is (-39.08 ± 0.01) mm. It should be understood that in this specification, the two radii of curvature of a lens are the radius of curvature of the laser incident surface of the lens and the radius of curvature of the laser exit surface of the lens, respectively. For example, the first radius of curvature of the first lens 1 corresponds to the radius of curvature of the laser incident surface of the first lens 1, and the second radius of curvature corresponds to the radius of curvature of the laser exit surface of the first lens 1.

[0044] In some embodiments, the third radius of curvature of the second lens 2 is in the range of (-35) to (-20) mm, and the fourth radius of curvature of the second lens 2 is in the range of 350 to 450 mm. In some embodiments, the third radius of curvature of the second lens 2 is in the range of (-30) to (-25) mm, and the fourth radius of curvature of the second lens 2 is in the range of 380 to 400 mm. In some embodiments, the third radius of curvature of the second lens 2 is in the range of (-27.10) to (-27.08) mm, and the fourth radius of curvature of the second lens 2 is in the range of 389.84 to 390.00 mm. In some embodiments, the third radius of curvature of the second lens 2 is (-27.09 ± 0.01) mm, and the fourth radius of curvature of the second lens 2 is 389.92 ± 0.08 mm. Wherein the third radius of curvature corresponds to the radius of curvature of the laser incident surface of the second lens 2 (i.e. the surface close to the first lens 1), and the fourth radius of curvature corresponds to the radius of curvature of the laser exit surface of the second lens 2 (i.e. the surface away from the first lens 1).

[0045] In some embodiments, the fifth radius of curvature of the third lens 3 is in the range of (-70) to (-60) mm, and the sixth radius of curvature of the third lens 3 is in the range of (-50) to (-40) mm. In some embodiments, the fifth radius of curvature of the third lens 3 is in the range of (-68) to (-62) mm, and the sixth radius of curvature of the third lens 3 is in the range of (-48) to (-42) mm. In some embodiments, the fifth radius of curvature of the third lens 3 is in the range of (-66.48) to (-66.46) mm, and the sixth radius of curvature of the third lens 3 is in the range of (-46.16) to (-46.14) mm. In some embodiments, the fifth radius of curvature of the third lens 3 is (-66.47 ± 0.01) mm, and the sixth radius of curvature of the third lens 3 is (-46.15 ± 0.01) mm. Wherein the fifth radius of curvature corresponds to the radius of curvature of the laser incident surface of the third lens 3, and the sixth radius of curvature corresponds to the radius of curvature of the laser exit surface of the third lens 3.

[0046] In some embodiments, the seventh radius of curvature of the fourth lens 4 is in the range of (-1390) to (-1360) mm, and the eighth radius of curvature of the fourth lens 4 is in the range of (-60) to (-40) mm. In some embodiments, the seventh radius of curvature of the fourth lens 4 is in the range of (-1380) to (-1370) mm, and the eighth radius of curvature of the fourth lens 4 is in the range of (-53) to (-48) mm. In some embodiments, the seventh radius of curvature of the fourth lens 4 is in the range of (-1378.59) to (-1378.55) mm, and the eighth radius of curvature of the fourth lens 4 is in the range of (-51.10) to (-51.08) mm. In some embodiments, the seventh radius of curvature of the fourth lens 4 is (-1378.57 ± 0.2) mm, and the eighth radius of curvature of the fourth lens 4 is (-51.09 ± 0.01) mm. The seventh radius of curvature corresponds to the radius of curvature of the laser incident surface of the fourth lens 4, and the eighth radius of curvature corresponds to the radius of curvature of the laser exit surface of the fourth lens 4.

[0047] In some embodiments, the ninth radius of curvature of the fifth lens 5 is in the range of 155 to 175 mm, and the tenth radius of curvature of the fifth lens 5 is in the range of (-265) to (-245) mm. In some embodiments, the ninth radius of curvature of the fifth lens 5 is in the range of 160 to 170 mm, and the tenth radius of curvature of the fifth lens 5 is in the range of (-260) to (-250) mm. In some embodiments, the ninth radius of curvature of the fifth lens 5 is in the range of 167.27 to 167.37 mm, and the tenth radius of curvature of the fifth lens 5 is in the range of (-252.71) to (-252.61) mm. In some embodiments, the ninth radius of curvature of the fifth lens 5 is 167.32 ± 0.05 mm, and the tenth radius of curvature of the fifth lens 5 is (-252.66 ± 0.05) mm. The ninth radius of curvature corresponds to the radius of curvature of the laser incident surface (i.e., the surface close to the fourth lens 4) of the fifth lens 5, and the tenth radius of curvature corresponds to the radius of curvature of the laser exit surface (i.e., the surface away from the fourth lens 4) of the fifth lens 5.

[0048] By setting appropriate radii of curvature, the focal length of each lens can be accurately controlled to meet the needs of different application scenarios, thereby reducing field curvature and distortion to achieve low field curvature and low distortion of the optical lens.

[0049] In some embodiments, the center thickness of the first lens 1 is in the range of 2–4 mm, the center thickness of the second lens 2 is in the range of 7–9 mm, the center thickness of the third lens 3 is in the range of 7.5–10 mm, the center thickness of the fourth lens 4 is in the range of 20–25 mm, and the center thickness of the fifth lens 5 is in the range of 19–24 mm. In some embodiments, the center thickness of the first lens 1 is in the range of 2.5–2.8 mm, the center thickness of the second lens 2 is in the range of 7.5–8.5 mm, the center thickness of the third lens 3 is in the range of 8–9 mm, the center thickness of the fourth lens 4 is in the range of 21–23 mm, and the center thickness of the fifth lens 5 is in the range of 20–23 mm. In some embodiments, the center thickness of the first lens 1 is in the range of 2.9–3.1 mm, the center thickness of the second lens 2 is in the range of 7.9–8.1 mm, the center thickness of the third lens 3 is in the range of 8.88–9.08 mm, the center thickness of the fourth lens 4 is in the range of 22.03–22.23 mm, and the center thickness of the fifth lens 5 is in the range of 21.59–21.79 mm. In some embodiments, the center thickness of the first lens 1 is in the range of 2.99–3.01 mm, the center thickness of the second lens 2 is in the range of 7.99–8.01 mm, the center thickness of the third lens 3 is in the range of 8.97–8.99 mm, the center thickness of the fourth lens 4 is in the range of 22.12–22.14 mm, and the center thickness of the fifth lens 5 is in the range of 21.68–21.70 mm. In some embodiments, the center thickness of the first lens 1 is 3 ± 0.01 mm, the center thickness of the second lens 2 is 8 ± 0.01 mm, the center thickness of the third lens 3 is 8.98 ± 0.01 mm, the center thickness of the fourth lens 4 is 22.13 ± 0.01 mm, and the center thickness of the fifth lens 5 is 21.69 ± 0.01 mm.

[0050] Since different wavelengths of light refract at greater angles when passing through thicker materials, lenses with a larger center thickness usually produce greater chromatic aberration. By limiting the center thickness of the lens, each lens can be set to an appropriate thickness, thereby reducing dispersion.

[0051] In some embodiments, the outer diameter of the first lens 1 is in the range of 28-35mm, the outer diameter of the second lens 2 is in the range of 45-50mm, the outer diameter of the third lens 3 is in the range of 58-65mm, the outer diameter of the fourth lens 4 is in the range of 78-85mm, the outer diameter of the fifth lens 5 is in the range of 88-95mm, and the outer diameter of the sixth lens 6 is in the range of 88-95mm. In some embodiments, the outer diameter of the first lens 1 is in the range of 31-33mm, the outer diameter of the second lens 2 is in the range of 47-49mm, the outer diameter of the third lens 3 is in the range of 60-62mm, the outer diameter of the fourth lens 4 is in the range of 80-82mm, the outer diameter of the fifth lens 5 is in the range of 90-92mm, and the outer diameter of the sixth lens 6 is in the range of 90-92mm. In some embodiments, the outer diameter of the first lens 1 is 32mm, the outer diameter of the second lens 2 is 48mm, the outer diameter of the third lens 3 is 61mm, the outer diameter of the fourth lens 4 is 81mm, the outer diameter of the fifth lens 5 is 91mm, and the outer diameter of the sixth lens 6 is 91mm.

[0052] The larger the outer diameter of the lens, the more light rays can be captured, thereby improving the resolution of the system and providing clearer image details, but too large an outer diameter will increase the volume of the lens. Therefore, by controlling the outer diameter of the lens within the above suitable range, both the resolution and the volume of the lens can be considered.

[0053] In some embodiments, the ratio of the focal length of the first lens 1 to the focal length of the optical lens is in the range of 1.6-1.8, the ratio of the focal length of the second lens 2 to the focal length of the optical lens is in the range of (-0.4)-(-0.3), the ratio of the focal length of the third lens 3 to the focal length of the optical lens is in the range of 2.4-2.6, the ratio of the focal length of the fourth lens 4 to the focal length of the optical lens is in the range of 0.9-1.1, and the ratio of the focal length of the fifth lens 5 to the focal length of the optical lens is in the range of 1.9-2. In some embodiments, the ratio of the focal length of the first lens 1 to the focal length of the optical lens is 1.62, the ratio of the focal length of the second lens 2 to the focal length of the optical lens is (-0.38), the ratio of the focal length of the third lens 3 to the focal length of the optical lens is 2.5, the ratio of the focal length of the fourth lens 4 to the focal length of the optical lens is 1.0, and the ratio of the focal length of the fifth lens 5 to the focal length of the optical lens is 1.95.

[0054] In some embodiments, the focal length of the optical lens is in the range of 100-120mm, the focal length of the first lens 1 is in the range of 170-180mm, the focal length of the second lens 2 is in the range of (-45)-(-40)mm, the focal length of the third lens 3 is in the range of 270-280mm, the focal length of the fourth lens 4 is in the range of 100-120mm, and the focal length of the fifth lens 5 is in the range of 210-220mm. In some embodiments, the focal length of the optical lens is in the range of 105-115mm, the focal length of the first lens 1 is in the range of 175-180mm, the focal length of the second lens 2 is in the range of (-43)-(-41)mm, the focal length of the third lens 3 is in the range of 275-278mm, the focal length of the fourth lens 4 is in the range of 105-115mm, and the focal length of the fifth lens 5 is in the range of 212-216mm. In some embodiments, the focal length of the optical lens is 110mm, the focal length of the first lens 1 is 178mm, the focal length of the second lens 2 is (-42)mm, the focal length of the third lens 3 is 276mm, the focal length of the fourth lens 4 is 110mm, and the focal length of the fifth lens 5 is 214mm.

[0055] By setting the focal length of each lens in the above reasonable range, the optical performance is guaranteed, i.e., the optical lens has low field curvature, low distortion and high MTF performance, while reducing the number of lenses, reducing cost, and reducing the size and weight of the device.

[0056] Chromatic aberration (dispersion) is caused by different refraction angles of light rays of different wavelengths when passing through a lens, resulting in different colors of light rays being focused at different positions. Abbe number, also known as dispersion coefficient, is used to measure the degree of light dispersion of a transparent medium.

[0057] Figure 2 is a schematic diagram of the optical path of the optical lens according to some embodiments of the present specification. In some embodiments, by limiting the ratio of the refractive index and the Abbe number of the optical lens, light rays of different wavelengths are focused as much as possible on the same plane, as shown in Figure 2 , thereby reducing chromatic aberration; not only helps to reduce aberrations (such as spherical aberration, coma, astigmatism, etc.), but also improves the overall imaging quality and resolution of the system; ensures that the focal plane of the entire optical system is more uniform, avoids the shift of focal point caused by the difference in dispersion between different lenses, thereby improving the consistency and clarity of imaging.

[0058] In some embodiments, the ratio of the refractive index to the Abbe number of the first lens 1 is in the range of 0.019-0.023, the ratio of the refractive index to the Abbe number of the second lens 2 is in the range of 0.031-0.035, the ratio of the refractive index to the Abbe number of the third lens 3 is in the range of 0.019-0.023, the ratio of the refractive index to the Abbe number of the fourth lens 4 is in the range of 0.019-0.023, the ratio of the refractive index to the Abbe number of the fifth lens 5 is in the range of 0.019-0.023, and the ratio of the refractive index to the Abbe number of the sixth lens 6 is in the range of 0.019-0.023. In some embodiments, the ratio of the refractive index to the Abbe number of the first lens 1 is in the range of 0.021-0.022, the ratio of the refractive index to the Abbe number of the second lens 2 is in the range of 0.033-0.034, the ratio of the refractive index to the Abbe number of the third lens 3 is in the range of 0.021-0.022, the ratio of the refractive index to the Abbe number of the fourth lens 4 is in the range of 0.021-0.022, the ratio of the refractive index to the Abbe number of the fifth lens 5 is in the range of 0.021-0.022, and the ratio of the refractive index to the Abbe number of the sixth lens 6 is in the range of 0.021-0.022. In some embodiments, the ratio of the refractive index to the Abbe number of the first lens 1 is 1.45846 / 67.82, the ratio of the refractive index to the Abbe number of the second lens 2 is 1.54814 / 45.75, the ratio of the refractive index to the Abbe number of the third lens 3 is 1.45846 / 67.82, the ratio of the refractive index to the Abbe number of the fourth lens 4 is 1.45846 / 67.82, the ratio of the refractive index to the Abbe number of the fifth lens 5 is 1.45846 / 67.82, and the ratio of the refractive index to the Abbe number of the sixth lens 6 is 1.45846 / 67.82.

[0059] By limiting the ratio of the refractive index to the Abbe number to the above ranges, the design of the optical system can be simplified, the number and complexity of the lenses can be reduced, thereby reducing the cost and improving the reliability of the system.

[0060] In some embodiments, the distance between the center of the first lens 1 and the center of the second lens 2 is in the range of 10-15 mm, the distance between the center of the second lens 2 and the center of the third lens 3 is in the range of 5-10 mm, the distance between the center of the third lens 3 and the center of the fourth lens 4 is in the range of 1-3 mm, the distance between the center of the fourth lens 4 and the center of the fifth lens 5 is in the range of 2-4 mm, and the distance between the center of the fifth lens 5 and the center of the sixth lens 6 is in the range of 3-7 mm. In some embodiments, the distance between the center of the first lens 1 and the center of the second lens 2 is in the range of 10-12 mm, the distance between the center of the second lens 2 and the center of the third lens 3 is in the range of 6-8 mm, the distance between the center of the third lens 3 and the center of the fourth lens 4 is in the range of 1.5-2.5 mm, the distance between the center of the fourth lens 4 and the center of the fifth lens 5 is in the range of 2.5-3.5 mm, and the distance between the center of the fifth lens 5 and the center of the sixth lens 6 is in the range of 4-6 mm. In some embodiments, the distance between the center of the first lens 1 and the center of the second lens 2 is in the range of 11.22-11.42 mm, the distance between the center of the second lens 2 and the center of the third lens 3 is in the range of 7.16-7.36 mm, the distance between the center of the third lens 3 and the center of the fourth lens 4 is in the range of 1.9-2.1 mm, the distance between the center of the fourth lens 4 and the center of the fifth lens 5 is in the range of 2.9-3.1 mm, and the distance between the center of the fifth lens 5 and the center of the sixth lens 6 is in the range of 4.9-5.1 mm. In some embodiments, the distance between the center of the first lens 1 and the center of the second lens 2 is 11.32±0.1 mm, the distance between the center of the second lens 2 and the center of the third lens 3 is 7.26±0.1 mm, the distance between the center of the third lens 3 and the center of the fourth lens 4 is 2±0.1 mm, the distance between the center of the fourth lens 4 and the center of the fifth lens 5 is 3±0.1 mm, and the distance between the center of the fifth lens 5 and the center of the sixth lens 6 is 5±0.1 mm. It should be understood that the center of a lens refers to the optical center of the lens, i.e., the direction of the light rays passing through the center (or optical center) does not change.

[0061] The distance between the lenses affects the resolution of the system. Too large a distance can result in a long light path, increasing aberration; too small a distance can result in insufficient convergence of light, affecting the resolution. Some embodiments of the present specification optimize the distance between the lenses to maintain good contrast transfer at different spatial frequencies, thereby improving the resolution of the system. The distance between the lenses affects the contrast transfer capability of the system. Some embodiments of the present specification set appropriate distances between adjacent lenses to ensure that the light maintains good contrast during transmission between lenses, avoiding loss of contrast due to excessive scattering or reflection.

[0062] Figure 3is a field curvature graph of the optical lens according to some embodiments of the present specification, and the corresponding distortion type is F-theta distortion. In the graph, the horizontal axis represents the field curvature, and the unit is millimeter; and the vertical axis represents the scanning angle, and the unit is °.

[0063] In some embodiments, as shown in Figure 3 the field curvature of the optical lens designed according to the above embodiments is less than or equal to 0.07 mm, the scanning angle of the optical lens is 18.6°, the scanning range of the optical lens is 50 mm x 50 mm, and the focal length is 110 mm. The scanning range is equal to the focal length of the optical lens multiplied by the tangent value of its incident angle. In some embodiments, the working distance of the optical lens is in the range of 140-150 mm. The working distance refers to the distance between the one side of the sixth lens 6 away from the fifth lens 5 and the focal point of the light beam. In some embodiments, the working distance of the optical lens is 146.4 ± 0.5 mm.

[0064] The optical lens according to some embodiments of the present specification realizes low field curvature, large scanning angle and large scanning range.

[0065] Figure 4 is an aberration analysis graph of the optical lens according to some embodiments of the present specification. The corresponding distortion type is F-theta distortion. In the graph, the horizontal axis represents the F-theta relative distortion, and the unit is percent (%); and the vertical axis represents the scanning angle, and the unit is °.

[0066] In some embodiments, as shown in Figure 4 the maximum distortion of the optical lens designed according to the above embodiments is less than or equal to 1%, i.e., the maximum F-theta relative distortion of the optical lens is less than or equal to 1%.

[0067] Figure 5 is a field curvature MTF graph of the optical lens according to some embodiments of the present specification. In the graph, the horizontal axis represents the spatial frequency, and the unit is cycle / mm; and the vertical axis represents the optical transfer function (OTF) modulus, i.e., MTF. The OTF is a function of the spatial frequency, which is used to express the transfer function of the image and the transfer function of the phase. The MTF is used to describe the response and resolution of the imaging system in the spatial frequency range.

[0068] In some embodiments, as shown in Figure 5 the modulation transfer function (MTF) of the optical lens designed according to the above embodiments is greater than or equal to 145@0.3.

[0069] The image-side telecentricity of the optical lens designed according to the above-mentioned embodiments is less than 0.9°. Telecentricity is used to describe the angle of the chief ray deviating from the optical axis. The object-side telecentricity is defined by the position of the entrance pupil in the object side, and the image-side telecentricity can be defined by the exit pupil at infinity in the object side.

[0070] The optical lens of some embodiments of the present specification realizes low distortion, high MTF and small image-side telecentricity.

[0071] Some embodiments of the present specification provide a laser processing system, comprising a laser, a scanning galvanometer and an optical lens for laser processing.

[0072] The laser is a device for emitting laser. Example lasers include gas lasers, solid-state lasers, semiconductor lasers and dye lasers, etc.

[0073] The scanning galvanometer is a light path scanning device, which can be applied to laser scanning, laser pattern display, etc.

[0074] The optical lens is the optical lens of any one of the preceding embodiments, which will not be described again.

[0075] In some embodiments, the central wavelength of the laser is 343 nm. The central wavelength refers to the central position of the wavelength distribution of the laser output.

[0076] The laser processing system of some embodiments of the present specification uses an ultraviolet band of 343 nm, which has a shorter wavelength and higher energy, and is widely used in scanning marking, punching, edge cutting and other applications. By using an optical lens with low field curvature, low distortion and high MTF performance, the chromatic dispersion problem of the ultraviolet band lens is effectively solved.

[0077] The above has described the basic concepts, and it is obvious that the above detailed disclosure is only used as an example and does not limit the present specification. Although it is not explicitly stated here, those skilled in the art can make various modifications, improvements and corrections to the present specification. Such modifications, improvements and corrections are suggested in the present specification, so such modifications, improvements and corrections still belong to the spirit and scope of the exemplary embodiments of the present specification.

[0078] At the same time, the present specification uses specific words to describe the embodiments of the present specification. As "one embodiment", "an embodiment" and / or "some embodiments" means a certain feature, structure or characteristic related to at least one embodiment of the present specification. Therefore, it should be emphasized and noted that the "an embodiment" or "one embodiment" or "one alternative embodiment" mentioned in different places in the present specification does not necessarily refer to the same embodiment. In addition, some features, structures or characteristics in one or more embodiments of the present specification can be properly combined.

[0079] Furthermore, the order of the processing elements and sequences, unless otherwise specified, can be varied, and the use of numbering might be schematically shown with the understanding that the items being referred to are the same item in the description whether visited explicitly or not. Additionally, structures and functionality presented as separate components in example configurations can be implemented as a combined structure or component by affording additional functionality, and vice versa. For example, while functions are presented herein as being performed by a server, a mobile device, or a combination thereof, the functions can be performed by a single device or a combination of devices. Moreover, while implementation of the system components described above can be realized by hardware devices, the implementation can also be realized by software solutions, such as installing the described system on an existing server or mobile device.

[0080] Similarly, it is to be noticed that the term "comprising", used in the description, should not be interpreted as being restricted to the means listed thereafter; it does not exclude other elements or steps. It is thus to be interpreted as specifying the presence of the stated features, integers, steps or components as referred to, but does not preclude the presence or addition of one or more other features, integers, steps or components, or groups thereof. Moreover, it is understood that the word "a" or "an", as used in the context of the specification, should not be construed to close the number of elements or features. Use of the indefinite article "a" or "an" is thus to be interpreted as meaning "one or more". The terms "first", "second" and the like, do not denote any order, quantity, combination or hierarchy, but are used to distinguish one element from another, and are interchangeable under appropriate circumstances. The terms "comprise", "comprising", "comprises", "include", "including", "includes", "contain", "containing", "contains", "characterized by" and the like, are used herein to specify the presence of stated features, integers, steps or components but do not preclude the presence or addition of one or more other features, integers, steps, components, or groups thereof.

[0081] Every patent, patent application, publication, document, article, book, or other material cited in this specification is hereby incorporated by reference in its entirety for all purposes to the same extent as if each individual publication, document, article, book, or other material were specifically and individually indicated to be incorporated by reference in its entirety for its full disclosure and nothing contained in this incorporation by reference is to be construed as an admission that the application is not entitled to antedate such publication, document, article, book, or other material by virtue of prior application. In the event of inconsistencies between the disclosure of this specification and the disclosures of the materials incorporated by reference, the disclosure of this specification shall control.

[0082] Finally, it should be understood that the embodiments described herein are intended to be illustrative only and in no way limiting of the scope of the present disclosure. Alterations and modifications of the embodiments described herein are possible using the principles of the present disclosure. Accordingly, although embodiments have been described which can contain specific elements, these are only examples and are not intended to limit the scope, applicability or configuration of the disclosure in any way. Rather, the scope of the disclosure should be determined by the language of the claims and the equivalents thereof.

Claims

1. An optical lens characterized in that, The first lens, the second lens, the third lens, the fourth lens, the fifth lens and the sixth lens are arranged in sequence along the laser incidence direction, The first lens is a meniscus lens with the convex surface direction consistent with the laser incidence direction, and the first lens has a positive focal length; The second lens is a double-concave lens, and the second lens has a negative focal length; The third lens is a meniscus lens with the convex surface direction consistent with the laser incidence direction, and the third lens has a positive focal length; The fourth lens is a meniscus lens with the convex surface direction consistent with the laser incidence direction, and the fourth lens has a positive focal length; The fifth lens is a double-convex lens, and the fifth lens has a positive focal length; The sixth lens is a protective flat plate; The maximum distortion of the optical lens is less than or equal to 1%, the modulation transfer function (MTF) of the optical lens is greater than or equal to 145@0.3, and the image-side telecentricity of the optical lens is less than 0.9°.

2. The optical lens of claim 1, wherein, The first curvature radius of the first lens is in the range of (-75)~(-65) mm, and the second curvature radius of the first lens is in the range of (-45)~(-35) mm; The third curvature radius of the second lens is in the range of (-35)~(-20) mm, and the fourth curvature radius of the second lens is in the range of 350~450 mm; The fifth curvature radius of the third lens is in the range of (-70)~(-60) mm, and the sixth curvature radius of the third lens is in the range of (-50)~(-40) mm; The seventh curvature radius of the fourth lens is in the range of (-1390)~(-1360) mm, and the eighth curvature radius of the fourth lens is in the range of (-60)~(-40) mm; The ninth curvature radius of the fifth lens is in the range of 155~175 mm, and the tenth curvature radius of the fifth lens is in the range of (-265)~(-245) mm.

3. The optical lens of claim 1, wherein, The center thickness of the first lens is in the range of 2~4 mm, the center thickness of the second lens is in the range of 7~9 mm, the center thickness of the third lens is in the range of 7.5~10 mm, the center thickness of the fourth lens is in the range of 20~25 mm, and the center thickness of the fifth lens is in the range of 19~24 mm.

4. The optical lens of claim 1, wherein, The outer diameter of the first lens is in the range of 28~35 mm, the outer diameter of the second lens is in the range of 45~50 mm, the outer diameter of the third lens is in the range of 58~65 mm, the outer diameter of the fourth lens is in the range of 78~85 mm, the outer diameter of the fifth lens is in the range of 88~95 mm, and the outer diameter of the sixth lens is in the range of 88~95 mm.

5. The optical lens of claim 1, wherein, The ratio of the focal length of the first lens to the focal length of the optical lens is in the range of 1.6-1.8, the ratio of the focal length of the second lens to the focal length of the optical lens is in the range of (-0.4)-(-0.3), the ratio of the focal length of the third lens to the focal length of the optical lens is in the range of 2.4-2.6, the ratio of the focal length of the fourth lens to the focal length of the optical lens is in the range of 0.9-1.1, and the ratio of the focal length of the fifth lens to the focal length of the optical lens is in the range of 1.9-2.

6. The optical lens of claim 1, wherein, The ratio of the refractive index to the Abbe number of the first lens is in the range of 0.019-0.023, the ratio of the refractive index to the Abbe number of the second lens is in the range of 0.031-0.035, the ratio of the refractive index to the Abbe number of the third lens is in the range of 0.019-0.023, the ratio of the refractive index to the Abbe number of the fourth lens is in the range of 0.019-0.023, the ratio of the refractive index to the Abbe number of the fifth lens is in the range of 0.019-0.023, and the ratio of the refractive index to the Abbe number of the sixth lens is in the range of 0.019-0.

023.

7. The optical lens of claim 1, wherein, The distance between the center of the first lens and the center of the second lens is in the range of 10-15mm, the distance between the center of the second lens and the center of the third lens is in the range of 5-10mm, the distance between the center of the third lens and the center of the fourth lens is in the range of 1-3mm, the distance between the center of the fourth lens and the center of the fifth lens is in the range of 2-4mm, and the distance between the center of the fifth lens and the center of the sixth lens is in the range of 3-7mm.

8. The optical lens of any of claims 1-7, wherein, The field curvature of the optical lens is less than or equal to 0.07mm, the scan angle of the optical lens is 18.6°, the scan surface of the optical lens is 50mm*50mm, and the working distance of the optical lens is in the range of 140-150mm.

9. A laser processing system characterized by comprising: The optical lens comprises a laser, a scan mirror, and an optical lens for laser processing, the optical lens is the optical lens according to any one of claims 1-8, and the central wavelength of the laser is 343nm.

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