A UV achromatic objective lens for laser microfluidics equipment processing head

Abstract

The invention discloses an ultraviolet achromatic objective lens for a processing head of a laser micro-jet device, belonging to the technical field of laser micro-jet devices. The processing head comprises a window, a water cavity and a nozzle, and the nozzle comprises a nozzle. The ultraviolet achromatic objective lens, the window, the water cavity and the nozzle are arranged in sequence along the optical axis direction of the ultraviolet achromatic objective lens. The ultraviolet achromatic objective lens is used to focus ultraviolet laser light into the water cavity and the nozzle. The ultraviolet achromatic objective lens comprises a first biconvex positive lens, a biconcave negative lens, a second biconvex positive lens and a meniscus positive lens group which are coaxially arranged in sequence. After being converged by the first biconvex positive lens, the ultraviolet laser light enters the biconcave negative lens, diverges through the biconcave negative lens, enters the second biconvex positive lens, converges through the second biconvex positive lens, enters the meniscus positive lens group, and converges through the meniscus positive lens group. After being converged by the meniscus positive lens group, the ultraviolet laser light sequentially passes through the window and the water cavity and enters the nozzle. Thus, the achromatic ability of the ultraviolet achromatic objective lens for ultraviolet laser light can be improved.

Description

Technical Field

[0001] The invention belongs to the technical field of laser micro-jet equipment, and in particular relates to an ultraviolet achromatic objective lens used for a processing head of a laser micro-jet equipment. Background Art

[0002] Laser microjet machining is a precision machining technology that uses a water jet to guide a laser beam to cut and drill holes in workpieces. Laser microjet equipment is a type of laser processing device that uses this technology. Typically, a laser microjet device consists of a mounting frame, a machining head, and a fixture. The machining head is mounted on the mounting frame for securement, while the fixture clamps the workpiece. Laser microjet is emitted from the machining head to perform laser machining on the workpiece in the fixture.

[0003] In the currently common laser microfluidics equipment suitable for ultraviolet laser processing, the processing head includes a laser emitter, an ultraviolet objective lens, and a coupling water chamber. The laser emitter is used to emit ultraviolet laser light, and the ultraviolet objective lens is used to focus the ultraviolet laser light into the coupling water chamber, which is used to provide a high-pressure water flow. The ultraviolet objective lens is a convex lens. With this structure, the ultraviolet laser light can be focused into the coupling water chamber through the convex lens, and then mixed with the high-pressure water flow in the coupling water chamber to form a water jet that impacts the surface of the workpiece. Under the guidance of the high-pressure water beam, the ultraviolet laser light in the water jet can penetrate the workpiece for processing. However, in the processing head of traditional laser microfluidics equipment, the ultraviolet objective lens has a weak ability to achromatize the ultraviolet laser light, which affects the imaging quality of the ultraviolet objective lens. Summary of the Invention

[0004] In order to solve the above problems existing in the prior art, the present invention provides a UV achromatic objective lens for a laser microfluidic device processing head. The technical problem to be solved by the present invention is achieved through the following technical solutions:

[0005] In a first aspect, the present invention provides an ultraviolet achromatic objective lens for a processing head of a laser microfluidic device, wherein the processing head includes a window, a water cavity, and a nozzle, wherein the nozzle includes a nozzle hole. The ultraviolet achromatic objective lens, the window, the water cavity, and the nozzle are sequentially arranged along the optical axis direction of the ultraviolet achromatic objective lens, and the ultraviolet achromatic objective lens is used to focus ultraviolet laser light into the water cavity and the nozzle hole.

[0006] The ultraviolet achromatic objective lens includes a first biconvex positive lens, a biconcave negative lens, a second biconvex positive lens and a meniscus positive lens group which are coaxially arranged in sequence. The ultraviolet laser is converged by the first biconvex positive lens and enters the biconcave negative lens. After being diverged by the biconcave negative lens, it enters the second biconvex positive lens. After being converged by the second biconvex positive lens, it enters the meniscus positive lens group. After being converged by the meniscus positive lens group, the ultraviolet laser passes through the window and the water cavity in sequence and enters the nozzle.

[0007] In one embodiment of the present invention, the absolute value of the radius of curvature of the upper surface of the first biconvex positive lens is smaller than the absolute value of the radius of curvature of the lower surface of the first biconvex positive lens, the absolute value of the radius of curvature of the upper surface of the second biconvex positive lens is smaller than the absolute value of the radius of curvature of the lower surface of the second biconvex positive lens, and the absolute value of the radius of curvature of the lower surface of the first biconvex positive lens is smaller than the absolute value of the radius of curvature of the upper surface of the second biconvex positive lens.

[0008] In one embodiment of the present invention, the meniscus positive lens group includes a first meniscus positive lens, a second meniscus positive lens, and a third meniscus positive lens;

[0009] A first biconvex positive lens, a biconcave negative lens, a second biconvex positive lens, a first meniscus positive lens, a second meniscus positive lens and a third meniscus positive lens are arranged in sequence. The ultraviolet laser is converged by the second biconvex positive lens and enters the first meniscus positive lens. After being converged by the first meniscus positive lens, it enters the second meniscus positive lens. After being converged by the second meniscus positive lens, it enters the third meniscus positive lens. After being converged by the third meniscus positive lens, the ultraviolet laser passes through the window and the water cavity in sequence and enters the spray hole.

[0010] In one embodiment of the present invention, the curvature radius of the upper surface of the first meniscus positive lens is greater than the curvature radius of the upper surface of the second meniscus positive lens, and the curvature radius of the lower surface of the first meniscus positive lens is greater than the curvature radius of the lower surface of the second meniscus positive lens.

[0011] In one embodiment of the present invention, the curvature radius of the upper surface of the second meniscus positive lens is greater than the curvature radius of the upper surface of the third meniscus positive lens, and the curvature radius of the lower surface of the second meniscus positive lens is greater than the curvature radius of the lower surface of the third meniscus positive lens.

[0012] In one embodiment of the present invention, the first biconvex positive lens has an upper surface curvature radius of 57.1 mm to 57.5 mm, a lower surface curvature radius of -59.4 mm to -59.0 mm, a refractive index of 1.44 to 1.48, and an Abbe number of 67.6 to 68.0;

[0013] The radius of curvature of the upper surface of the biconcave negative lens is -92.2mm~-91.8mm, the radius of curvature of the lower surface is 34.7mm~35.1mm, the refractive index is 1.60~1.64, and the Abbe number is 36.2~36.6;

[0014] The second biconvex positive lens has an upper surface curvature radius of 77.2 mm to 77.6 mm, a lower surface curvature radius of -113.5 mm to -113.1 mm, a refractive index of 1.42 to 1.46, and an Abbe number of 94.3 to 94.7.

[0015] The curvature radius of the upper surface of the first meniscus positive lens is 37.8mm~38.2mm, the curvature radius of the lower surface is 341mm~345mm, the refractive index is 1.42~1.46, and the Abbe number is 94.3~94.7;

[0016] The curvature radius of the upper surface of the second meniscus positive lens is 23.0mm~23.4mm, the curvature radius of the lower surface is 55.3mm~55.7mm, the refractive index is 1.44~1.47, and the Abbe number is 67.6~68.0;

[0017] The curvature radius of the upper surface of the third meniscus positive lens is 11.2mm~11.6mm, the curvature radius of the lower surface is 14.6mm~15.0mm, the refractive index is 1.44~1.47, and the Abbe number is 67.6~68.0.

[0018] In one embodiment of the present invention, the refractive index of the window is 1.44-1.47, and the Abbe number is 94.3-94.7; the refractive index of the water cavity is 1.31-1.35, and the Abbe number is 55.6-56.0.

[0019] In one embodiment of the present invention, the lens barrel is further provided with a first spacer, a second spacer, and a third spacer;

[0020] The first spacer is arranged between the first biconvex positive lens and the biconcave negative lens, the second spacer is arranged between the biconcave negative lens and the second biconvex positive lens, and the third spacer is arranged between the second biconvex positive lens and the first meniscus positive lens.

[0021] In one embodiment of the present invention, it further comprises a first pressing ring, a second pressing ring and a third pressing ring;

[0022] The first pressing ring and the first spacer ring are respectively arranged on both sides of the first biconvex positive lens, the second pressing ring is arranged between the first meniscus positive lens and the second meniscus positive lens, and the third pressing ring is arranged between the second meniscus positive lens and the third meniscus positive lens;

[0023] The first pressing ring, the second pressing ring and the third pressing ring are all connected to the inner wall of the lens barrel through threads.

[0024] In one embodiment of the present invention, the outer circumferential surfaces of the first pressure ring, the second pressure ring and the third pressure ring are respectively provided with a first external thread, a second external thread and a third external thread, and the inner wall of the lens barrel is respectively provided with a first internal thread, a second internal thread and a third internal thread, and the first external thread, the second external thread and the third external thread are respectively threadedly matched with the first internal thread, the second internal thread and the third internal thread.

[0025] In second aspect, the present invention provides a processing head for a laser microjet device, comprising a window, a water chamber, a nozzle and an ultraviolet achromatic objective lens provided in the above scheme, the nozzle comprising a nozzle, the ultraviolet achromatic objective lens, the window, the water chamber and the nozzle are arranged in sequence along the optical axis direction of the ultraviolet achromatic objective lens, and the ultraviolet achromatic objective lens is used to focus the ultraviolet laser.

[0026] In a third aspect, the present invention provides a laser micro-fluidic device, including a processing head of the laser micro-fluidic device provided by the above solution.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] In the above scheme of the present application, the ultraviolet achromatic objective lens is applied to the processing head of the laser microjet device, the processing head includes a window, a water chamber and a nozzle, the nozzle includes a nozzle, the ultraviolet achromatic objective lens, the window, the water chamber and the nozzle are arranged in sequence along the optical axis direction of the ultraviolet achromatic objective lens, and the ultraviolet achromatic objective lens is used to focus the ultraviolet laser into the water chamber and the nozzle; the ultraviolet achromatic objective lens includes a first biconvex positive lens, a biconcave negative lens, a second biconvex positive lens and a meniscus positive lens group that are coaxially arranged in sequence, the ultraviolet laser is converged by the first biconvex positive lens and enters the biconcave negative lens, diverges through the biconcave negative lens and enters the second biconvex positive lens, converges through the second biconvex positive lens and enters the meniscus positive lens group, and converges through the meniscus positive lens group and passes through the window and the water chamber in sequence to enter the nozzle. With this structure, the first biconvex positive lens can provide positive optical power, positive spherical aberration, and negative chromatic aberration; the biconcave negative lens can provide negative optical power, negative spherical aberration, and positive chromatic aberration; the second biconvex positive lens can provide positive optical power, positive spherical aberration, and negative chromatic aberration; and the meniscus positive lens group can provide positive optical power and negative chromatic aberration. In this way, through the mutual cooperation of the first biconvex positive lens, the biconcave negative lens, the second biconvex positive lens, and the meniscus positive lens group, dispersion compensation and optical power balance of the ultraviolet achromatic objective lens can be achieved, thereby correcting chromatic aberration and improving the achromatic ability and imaging quality of the ultraviolet achromatic objective lens.

[0029] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 Schematic diagram of an ultraviolet achromatic objective lens in an embodiment of the present invention;

[0031] Figure 2 Schematic diagram of the optical path of the ultraviolet achromatic objective lens in an embodiment of the present invention;

[0032] Figure 3 is a point diagram of the ultraviolet achromatic objective lens in an embodiment of the present invention;

[0033] Figure 4 is a light fan diagram of the ultraviolet achromatic objective lens in an embodiment of the present invention;

[0034] Figure 5 is an axial aberration diagram of the ultraviolet achromatic objective lens in an embodiment of the present invention;

[0035] Figure 6 Graph showing the optical transfer function of the ultraviolet achromatic objective lens according to an embodiment of the present invention.

[0036] Figure numerals: 1-first biconvex positive lens, 2-biconcave negative lens, 3-second biconvex positive lens, 4-first meniscus positive lens, 5-second meniscus positive lens, 6-third meniscus positive lens, 7-window, 8-water chamber, 9-nozzle, 10-first pressure ring, 11-first spacer ring, 12-second spacer ring, 13-third spacer ring, 14-second pressure ring, 15-third pressure ring, 16-lens barrel. DETAILED DESCRIPTION

[0037] The present invention will be further described in detail below with reference to specific examples, but the embodiments of the present invention are not limited thereto.

[0038] Example 1:

[0039] See Figure 1 and Figure 2 An embodiment of the present invention provides an ultraviolet achromatic objective lens for a processing head of a laser microjet device. The processing head includes a window 7, a water cavity 8 and a nozzle 9. The nozzle 9 includes a nozzle. The ultraviolet achromatic objective lens, the window 7, the water cavity 8 and the nozzle 9 are arranged in sequence along the optical axis direction of the ultraviolet achromatic objective lens. The ultraviolet achromatic objective lens is used to focus the ultraviolet laser into the water cavity 8 and the nozzle. The ultraviolet achromatic objective lens includes a first biconvex positive lens 1, a biconcave negative lens 2, a second biconvex positive lens 3 and a meniscus positive lens group that are coaxially arranged in sequence. The ultraviolet laser is converged by the first biconvex positive lens 1 and enters the biconcave negative lens 2. After being diverged by the biconcave negative lens 2, it enters the second biconvex positive lens 3. After being converged by the second biconvex positive lens 3, it enters the meniscus positive lens group. After being converged by the meniscus positive lens group, the ultraviolet laser passes through the window 7 and the water cavity 8 in sequence and enters the nozzle.

[0040] In some embodiments of the present application, ultraviolet laser light is generated by frequency-doubled infrared laser light. Its wavelength is shorter than that of infrared and green laser light, and its beam photon energy is higher, typically at a wavelength of 355 nm. Compared to infrared and green laser light, ultraviolet laser light has a stronger ionization effect on materials, significantly reducing the thermal effects of materials and lowering the risk of carbonization, microcracking, and thermal deformation.

[0041] In some embodiments of the present application, the first biconvex positive lens 1 is a lens structure with both surfaces being convex. The first biconvex positive lens 1 converges the light beam and provides positive optical power, positive spherical aberration, and negative chromatic aberration. Spherical aberration and chromatic aberration are both common aberration phenomena in optical systems. Spherical aberration includes positive spherical aberration and negative spherical aberration, while chromatic aberration includes positive chromatic aberration and negative chromatic aberration.

[0042] In some embodiments of the present application, the biconcave negative lens 2 is a lens structure with two concave surfaces. The biconcave negative lens 2 diverges the light beam and provides negative optical power, negative spherical aberration and positive chromatic aberration.

[0043] In some embodiments of the present application, the second biconvex positive lens 3 is a lens structure with two convex surfaces. The second biconvex positive lens 3 converges the light beam and provides positive optical power, positive spherical aberration and negative chromatic aberration.

[0044] In some embodiments of the present application, the meniscus positive lens group includes one or more meniscus positive lenses. The meniscus positive lens is a lens structure composed of two curved surfaces with similar curvature radii and has a meniscus shape. The meniscus positive lens has a converging effect on the light beam and provides positive optical power and negative chromatic aberration.

[0045] In some embodiments of the present application, the first biconvex positive lens 1, the biconcave negative lens 2, the second biconvex positive lens 3 and the meniscus positive lens group are coaxially arranged in sequence, which means that the first biconvex positive lens 1, the biconcave negative lens 2, the second biconvex positive lens 3 and the meniscus positive lens group are arranged in sequence along the optical axis direction of the first biconvex positive lens 1.

[0046] In some embodiments of the present application, the optical axis direction of the ultraviolet achromatic objective lens coincides with the axial direction of the nozzle, so that the focusing spot of the ultraviolet achromatic objective lens can be located at the nozzle, so that the ultraviolet laser can be directly ejected from the nozzle after being focused by the ultraviolet achromatic objective lens, thereby improving the processing quality of laser processing.

[0047] In some embodiments of the present application, the processing head of the laser micro-jet device further includes an ultraviolet laser emitter, which can emit ultraviolet laser light. The ultraviolet laser emitter and the first biconvex positive lens 1 are arranged opposite to each other.

[0048] In the above scheme of the present application, the ultraviolet achromatic objective lens is applied to the processing head of the laser microjet device, the processing head includes a window 7, a water cavity 8 and a nozzle 9, the nozzle 9 includes a nozzle, the ultraviolet achromatic objective lens, the window 7, the water cavity 8 and the nozzle 9 are arranged in sequence along the optical axis direction of the ultraviolet achromatic objective lens, and the ultraviolet achromatic objective lens is used to focus the ultraviolet laser into the water cavity 8 and the nozzle; the ultraviolet achromatic objective lens includes a first biconvex positive lens 1, a biconcave negative lens 2, a second biconvex positive lens 3 and a meniscus positive lens group which are coaxially arranged in sequence, the ultraviolet laser is converged by the first biconvex positive lens 1 and enters the biconcave negative lens 2, diverges through the biconcave negative lens 2 and enters the second biconvex positive lens 3, converges through the second biconvex positive lens 3 and enters the meniscus positive lens group, and converges through the meniscus positive lens group and passes through the window 7 and the water cavity 8 in sequence to enter the nozzle. With this structure, the first biconvex positive lens 1 can provide positive optical power, positive spherical aberration, and negative chromatic aberration; the biconcave negative lens 2 can provide negative optical power, negative spherical aberration, and positive chromatic aberration; the second biconvex positive lens 3 can provide positive optical power, positive spherical aberration, and negative chromatic aberration; and the meniscus positive lens group can provide positive optical power and negative chromatic aberration. Thus, through the mutual cooperation of the first biconvex positive lens 1, the biconcave negative lens 2, the second biconvex positive lens 3, and the meniscus positive lens group, dispersion compensation and optical power balance of the ultraviolet achromatic objective lens can be achieved, thereby correcting chromatic aberration and improving the achromatic capability and imaging quality of the ultraviolet achromatic objective lens.

[0049] In some embodiments of the present application, the absolute value of the radius of curvature of the upper surface of the first biconvex positive lens 1 is smaller than the absolute value of the radius of curvature of the lower surface of the first biconvex positive lens 1, the absolute value of the radius of curvature of the upper surface of the second biconvex positive lens 3 is smaller than the absolute value of the radius of curvature of the lower surface of the second biconvex positive lens 3, and the absolute value of the radius of curvature of the lower surface of the first biconvex positive lens 1 is smaller than the absolute value of the radius of curvature of the upper surface of the second biconvex positive lens 3. With this structure, when the absolute value of the radius of curvature of the upper surface of the first biconvex positive lens 1 is smaller than the absolute value of the radius of curvature of the lower surface of the first biconvex positive lens 1, the first biconvex positive lens 1 is an aspheric lens. The use of an aspheric lens can further correct the spherical aberration and chromatic aberration of the ultraviolet achromatic objective lens, thereby improving the processing quality and efficiency of laser processing. When the absolute value of the radius of curvature of the upper surface of the second biconvex positive lens 3 is smaller than the absolute value of the radius of curvature of the lower surface of the second biconvex positive lens 3, the second biconvex positive lens 3 is an aspheric lens. The use of an aspheric lens can further correct the spherical aberration and chromatic aberration of the ultraviolet achromatic objective lens, thereby improving the processing quality and efficiency of laser processing.

[0050] In some embodiments of the present application, the meniscus positive lens group includes a first meniscus positive lens 4, a second meniscus positive lens 5, and a third meniscus positive lens 6; a first biconvex positive lens 1, a biconcave negative lens 2, a second biconvex positive lens 3, a first meniscus positive lens 4, a second meniscus positive lens 5, and a third meniscus positive lens 6 are arranged in sequence, and the ultraviolet laser is converged by the second biconvex positive lens 3 and enters the first meniscus positive lens 4, and then converged by the first meniscus positive lens 4 and enters the second meniscus positive lens 5, and then converged by the second meniscus positive lens 5 and enters the third meniscus positive lens 6, and then converged by the third meniscus positive lens 6 and sequentially passes through the window 7 and the water cavity 8 into the nozzle. With this structure, the cooperation of the first meniscus positive lens 4, the second meniscus positive lens 5, and the third meniscus positive lens 6 can further correct chromatic aberration and improve the processing quality and efficiency of laser processing.

[0051] In some embodiments of the present application, the first meniscus positive lens 4 can converge the light beam and provide positive optical focal length and negative chromatic aberration; the second meniscus positive lens 5 can converge the light beam and provide positive optical focal length and negative chromatic aberration; the third meniscus positive lens 6 can converge the light beam and provide positive optical focal length and negative chromatic aberration.

[0052] In some embodiments of the present application, the radius of curvature of the upper surface of the first meniscus positive lens 4 is greater than the radius of curvature of the upper surface of the second meniscus positive lens 5, and the radius of curvature of the lower surface of the first meniscus positive lens 4 is greater than the radius of curvature of the lower surface of the second meniscus positive lens 5. With this structure, the first meniscus positive lens 4 and the second meniscus positive lens 5 can further optimize the propagation path of the laser, improve the focusing effect and achromatic effect of the ultraviolet achromatic objective lens on the ultraviolet laser, and further improve the processing quality and efficiency of laser processing.

[0053] In some embodiments of the present application, the radius of curvature of the upper surface of the second meniscus positive lens 5 is greater than the radius of curvature of the upper surface of the third meniscus positive lens 6, and the radius of curvature of the lower surface of the second meniscus positive lens 5 is greater than the radius of curvature of the lower surface of the third meniscus positive lens 6. With this structure, the second meniscus positive lens 5 and the third meniscus positive lens 6 can further optimize the propagation path of the laser, improve the focusing effect and achromatic effect of the ultraviolet achromatic objective lens on the ultraviolet laser, and further improve the processing quality and efficiency of laser processing.

[0054] In some embodiments of the present application, the ultraviolet achromatic objective lens further includes a lens barrel 16, within which are disposed a first spacer 11, a second spacer 12, and a third spacer 13; the first spacer 11 is disposed between the first biconvex positive lens 1 and the biconcave negative lens 2, the second spacer 12 is disposed between the biconcave negative lens 2 and the second biconvex positive lens 3, and the third spacer 13 is disposed between the second biconvex positive lens 3 and the first meniscus positive lens 4. This structure allows for greater stability during installation of the first biconvex positive lens 1, the biconcave negative lens 2, and the second biconvex positive lens 3.

[0055] In some embodiments of the present application, the first spacer 11 , the second spacer 12 and the third spacer 13 are all smooth metal rings.

[0056] In some embodiments of the present application, the ultraviolet achromatic objective lens further includes a first pressing ring 10, a second pressing ring 14, and a third pressing ring 15; the first pressing ring 10 and the first spacer 11 are respectively arranged on both sides of the first biconvex positive lens 1, the second pressing ring 14 is arranged between the first meniscus positive lens 4 and the second meniscus positive lens 5, and the third pressing ring 15 is arranged between the second meniscus positive lens 5 and the third meniscus positive lens 6; the first pressing ring 10, the second pressing ring 14, and the third pressing ring 15 are all threadedly connected to the inner wall of the lens barrel 16. With this structure, through the cooperation of the first pressing ring 10, the second pressing ring 14, and the third pressing ring 15 with the inner wall thread of the lens barrel 16, the first biconvex positive lens 1, the biconcave negative lens 2, the second biconvex positive lens 3, the first meniscus positive lens 4, the second meniscus positive lens 5, and the third meniscus positive lens 6 can be made more stable during installation.

[0057] In some embodiments of the present application, the outer circumferences of the first pressing ring 10, the second pressing ring 14, and the third pressing ring 15 are respectively provided with first external threads, second external threads, and third external threads, and the inner wall of the lens barrel 16 is respectively provided with first internal threads, second internal threads, and third internal threads, and the first external threads, second external threads, and third external threads are respectively threadedly engaged with the first internal threads, second internal threads, and third internal threads. This structure makes it easier to install the first pressing ring 10, the second pressing ring 14, and the third pressing ring 15.

[0058] In some embodiments of the present application, the first internal thread and the first external thread are threadedly matched, the second internal thread and the second external thread are threadedly matched, and the third internal thread and the third external thread are threadedly matched.

[0059] In some embodiments of the present application, the first pressure ring 10 , the first spacer ring 11 , the second spacer ring 12 , the third spacer ring 13 , the second pressure ring 14 and the third pressure ring 15 are sequentially arranged along the axial direction of the lens barrel 16 .

[0060] In some embodiments of the present application, the first pressing ring 10 , the second pressing ring 14 and the third pressing ring 15 are all metal rings provided with external threads.

[0061] In some embodiments of the present application, the inner wall of the lens barrel 16 is further provided with a first boss, a second boss, and a third boss. The first meniscus positive lens 4 is mounted on the first boss. When the first pressing ring 10 is threadedly engaged with the inner wall of the lens barrel 16, the first biconvex positive lens 1, the biconcave negative lens 2, the second biconvex positive lens 3, and the first meniscus positive lens 4 are sequentially pressed onto the first boss. The second meniscus positive lens 5 is mounted on the second boss. When the second pressing ring 14 is threadedly engaged with the inner wall of the lens barrel 16, the second meniscus positive lens 5 can be pressed onto the second boss. The third meniscus positive lens 6 is mounted on the third boss. When the third pressing ring 15 is threadedly engaged with the inner wall of the lens barrel 16, the third meniscus positive lens 6 can be pressed onto the third boss.

[0062] In some embodiments of the present application, the curvature radius of the upper surface of the first biconvex positive lens 1 is 57.1 mm to 57.5 mm, the curvature radius of the lower surface is -59.4 mm to -59.0 mm, the refractive index is 1.44 to 1.48, preferably 1.46, and the Abbe number is 67.6 to 68.0, preferably 67.8; the curvature radius of the upper surface of the biconcave negative lens 2 is -92.2 mm to -91.8 mm, and the curvature radius of the lower surface is -92.2 mm to -91.8 mm. The second biconvex positive lens 3 has a radius of curvature of the upper surface of 77.2 mm to 77.6 mm, a radius of curvature of the lower surface of -113.5 mm to -113.1 mm, a refractive index of 1.42 to 1.46, preferably 1.44, and an Abbe number of 94.3 to 94. 7, preferably 94.5; the curvature radius of the upper surface of the first meniscus positive lens 4 is 37.8mm~38.2mm, the curvature radius of the lower surface is 341mm~345mm, the refractive index is 1.42~1.46, preferably 1.44, and the Abbe number is 94.3~94.7, preferably 94.5; the curvature radius of the upper surface of the second meniscus positive lens 5 is 23.0mm~23.4mm, and the curvature radius of the lower surface is 55.3m m~55.7mm, the refractive index is 1.44~1.47, preferably 1.46, and the Abbe number is 67.6~68.0, preferably 67.8; the curvature radius of the upper surface of the third meniscus positive lens 6 is 11.2mm~11.6mm, the curvature radius of the lower surface is 14.6mm~15.0mm, the refractive index is 1.44~1.47, preferably 1.46, and the Abbe number is 67.6~68.0, preferably 67.8. With this structure, multiple tests are conducted to optimize the specific values ​​of the curvature radius, refractive index and Abbe number of the two surfaces of each lens, thereby further optimizing the optical path of the ultraviolet laser, avoiding the influence of the curvature radius, refractive index and Abbe number being too high or too low on the focusing effect of the ultraviolet achromatic objective lens on the ultraviolet laser, thereby improving the processing quality and processing efficiency of laser processing.

[0063] In some embodiments of the present application, the refractive index of the window 7 is 1.44-1.47, and the Abbe number is 94.3-94.7; the refractive index of the water cavity 8 is 1.31-1.35, and the Abbe number is 55.6-56.0. Through multiple tests, the specific values ​​of the refractive index and Abbe number of the window 7 and the water cavity 8 are optimized, thereby further optimizing the optical path of the ultraviolet laser, avoiding the impact of excessively high or low refractive index and Abbe number on the focusing effect of the processing head on the ultraviolet laser, and thus improving the processing quality and efficiency of laser processing.

[0064] Table 1 below shows the specific values ​​of the surface shape, curvature radius, thickness, refractive index, Abbe number and clear aperture of the first biconvex positive lens 1, the biconcave negative lens 2, the second biconvex positive lens 3, the first meniscus positive lens 4, the second meniscus positive lens 5, the third meniscus positive lens 6, the window 7 and the water cavity 8.

[0065] Table 1

[0066]

[0067] The present invention tested a UV achromatic objective lens based on the data in Table 1. The optical system had an entrance pupil diameter of 30 mm, a primary beam wavelength of 0.355 μm, and was composed of ultraviolet laser light. The secondary beam had a wavelength of 0.480 μm and was composed of blue light. The focal length of the optical system was 26 mm, and the image-side numerical aperture was 0.5.

[0068] Figure 3 The spot diagram of the UV achromatic objective lens in the first embodiment is shown, where the image plane is 0 mm, the object plane is 0 degrees, the root mean square radius (RMS) of the main beam and the side beam is 0.022 μm, the geostationary Earth Orbit Radius (GEO) is 0.047, the scale size is 0.1, and the reference ray is the main ray. Figure 3 It can be seen that the RMS radii of the main beam and the side beam are similar, and the focal points of the main beam and the side beam and the image plane are relatively concentrated. Therefore, the ultraviolet achromatic objective lens in the embodiment of the present invention has good imaging quality and focusing effect.

[0069] Figure 4 The diagram of the light fan aberration of the ultraviolet achromatic objective lens in the first embodiment is shown, where the object plane is 0 degrees, the maximum zoom ratio is 0.1 μm, Px and Py are normalized pupil coordinates, representing the horizontal and vertical coordinates of the light on the pupil plane, respectively, and ex and ey are the horizontal and vertical coordinates of the light on the image plane, respectively. The solid line represents the main beam with a wavelength of 355 nm, and the dotted line represents the secondary beam with a wavelength of 480 nm. Figure 4 It can be seen that the curves of the main beam and the side beam have a small degree of fluctuation and a small difference between the two. The maximum lateral aberration of the main beam and the side beam is only 0.1 μm. Therefore, the ultraviolet achromatic objective lens in the embodiment of the present invention has a small lateral aberration, good imaging quality, and good focusing effect.

[0070] Figure 5The focus shift diagram of the ultraviolet achromatic objective lens in the first embodiment is shown, wherein the pupil radius is 15 mm, the abscissa represents the axial aberration, the ordinate represents the normalized aperture height of the incident light, curve a represents the main beam with a wavelength of 355 nm, and curve b represents the secondary beam with a wavelength of 480 nm. Figure 5 As can be seen, the focal positions of the main beam and the secondary beam are close, with the axial focal position difference between the main beam and the secondary beam being approximately 0.6 μm. The focal depth of the UV laser with a beam quality of 1.3 under the UV achromatic objective lens is approximately 3.2 μm, fully meeting the achromatic aberration requirements for the UV laser and the illumination beam. Therefore, the UV achromatic objective lens of the embodiment of the present invention has low axial chromatic aberration, good imaging quality, and good focusing effect, achieving the purpose of achromatization.

[0071] Figure 6 The optical transfer function diagram of the ultraviolet achromatic objective lens in the first embodiment is shown, wherein the horizontal axis represents the spatial frequency and the vertical axis represents the optical transfer function (OTF) modulus. Figure 6 It can be seen that the modulation transfer function curve in this optical system has coincided with the diffraction limit, indicating that the aberration of this optical system is extremely small and fully meets the usage requirements.

[0072] Example 2:

[0073] This embodiment provides a processing head for a laser microjet device, including a window, a water chamber, a nozzle, and an ultraviolet achromatic objective lens as provided in the above scheme. The nozzle includes a nozzle hole, and the ultraviolet achromatic objective lens, the window, the water chamber, and the nozzle are arranged in sequence along the optical axis direction of the ultraviolet achromatic objective lens. The ultraviolet achromatic objective lens is used to focus the ultraviolet laser.

[0074] The beneficial effects of the second embodiment of the present invention and its various implementations can be analyzed with reference to the beneficial effects of the first embodiment and its various implementations, and will not be repeated here.

[0075] Example 3:

[0076] The present invention provides a laser micro-fluidic device, including a processing head of the laser micro-fluidic device provided in the above-mentioned embodiment 2.

[0077] The beneficial effects of the third embodiment of the present invention and its various implementations can be analyzed with reference to the beneficial effects of the first embodiment and its various implementations, and will not be repeated here.

[0078] In the description of the present invention, it should be understood that the terms "up", "down", "front", "back", "left", "right", "inside", "outside", etc., indicating directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, they should not be understood as limiting the present invention.

[0079] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature identified with "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, "plurality" means two or more, unless otherwise specifically defined.

[0080] In the present invention, unless otherwise expressly specified or limited, the terms "mounted," "connected," "connect," "fixed," etc. should be understood broadly. For example, they may refer to fixed connection, detachable connection, or integration; mechanical connection or electrical connection; direct connection or indirect connection through an intermediate medium; internal communication between two components or interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0081] The above is a further detailed description of the present invention in conjunction with specific preferred embodiments, and the specific implementation of the present invention should not be considered to be limited to these descriptions. For those skilled in the art of the present invention, without departing from the concept of the present invention, several simple deductions or substitutions can be made, which should be considered to fall within the scope of protection of the present invention.

Claims

1. A UV achromatic objective lens for a laser microfluidic device processing head, characterized in that: The processing head includes a window, a water cavity and a nozzle, the nozzle includes a nozzle hole, the ultraviolet achromatic objective lens, the window, the water cavity and the nozzle are arranged in sequence along the optical axis direction of the ultraviolet achromatic objective lens, and the ultraviolet achromatic objective lens is used to focus the ultraviolet laser into the water cavity and the nozzle hole; The ultraviolet achromatic objective lens includes a first biconvex positive lens, a biconcave negative lens, a second biconvex positive lens, and a meniscus positive lens group that are coaxially arranged in sequence. The ultraviolet laser is converged by the first biconvex positive lens and enters the biconcave negative lens. After being diverged by the biconcave negative lens, it enters the second biconvex positive lens. After being converged by the second biconvex positive lens, it enters the meniscus positive lens group. After being converged by the meniscus positive lens group, the ultraviolet laser sequentially passes through the window and the water cavity and enters the nozzle. wherein the absolute value of the radius of curvature of the upper surface of the first biconvex positive lens is smaller than the absolute value of the radius of curvature of the lower surface of the first biconvex positive lens, the absolute value of the radius of curvature of the upper surface of the second biconvex positive lens is smaller than the absolute value of the radius of curvature of the lower surface of the second biconvex positive lens, and the absolute value of the radius of curvature of the lower surface of the first biconvex positive lens is smaller than the absolute value of the radius of curvature of the upper surface of the second biconvex positive lens; Wherein, the meniscus positive lens group includes a first meniscus positive lens, a second meniscus positive lens and a third meniscus positive lens; The first biconvex positive lens, the biconcave negative lens, the second biconvex positive lens, the first meniscus positive lens, the second meniscus positive lens, and the third meniscus positive lens are arranged in sequence. The ultraviolet laser is converged by the second biconvex positive lens and enters the first meniscus positive lens. After being converged by the first meniscus positive lens, it enters the second meniscus positive lens. After being converged by the second meniscus positive lens, it enters the third meniscus positive lens. After being converged by the third meniscus positive lens, the ultraviolet laser sequentially passes through the window and the water cavity and enters the spray hole. The curvature radius of the upper surface of the first meniscus positive lens is greater than the curvature radius of the upper surface of the second meniscus positive lens, and the curvature radius of the lower surface of the first meniscus positive lens is greater than the curvature radius of the lower surface of the second meniscus positive lens. The curvature radius of the upper surface of the second meniscus positive lens is greater than the curvature radius of the upper surface of the third meniscus positive lens, and the curvature radius of the lower surface of the second meniscus positive lens is greater than the curvature radius of the lower surface of the third meniscus positive lens. The first biconvex positive lens has an upper surface curvature radius of 57.1 mm to 57.5 mm, a lower surface curvature radius of -59.4 mm to -59.0 mm, a refractive index of 1.44 to 1.48, and an Abbe number of 67.6 to 68.

0. The curvature radius of the upper surface of the biconcave negative lens is -92.2 mm to -91.8 mm, the curvature radius of the lower surface is 34.7 mm to 35.1 mm, the refractive index is 1.60 to 1.64, and the Abbe number is 36.2 to 36.6; The second biconvex positive lens has an upper surface curvature radius of 77.2 mm to 77.6 mm, a lower surface curvature radius of -113.5 mm to -113.1 mm, a refractive index of 1.42 to 1.46, and an Abbe number of 94.3 to 94.7; The first meniscus positive lens has an upper surface curvature radius of 37.8 mm to 38.2 mm, a lower surface curvature radius of 341 mm to 345 mm, a refractive index of 1.42 to 1.46, and an Abbe number of 94.3 to 94.7; The curvature radius of the upper surface of the second meniscus positive lens is 23.0 mm to 23.4 mm, the curvature radius of the lower surface is 55.3 mm to 55.7 mm, the refractive index is 1.44 to 1.47, and the Abbe number is 67.6 to 68.0; The curvature radius of the upper surface of the third meniscus positive lens is 11.2 mm to 11.6 mm, the curvature radius of the lower surface is 14.6 mm to 15.0 mm, the refractive index is 1.44 to 1.47, and the Abbe number is 67.6 to 68.

0.

2. The ultraviolet achromatic objective lens for a laser microfluidics processing head according to claim 1, characterized in that: The refractive index of the window is 1.44-1.47, and the Abbe number is 94.3-94.7; The refractive index of the water cavity is 1.31-1.35, and the Abbe number is 55.6-56.

0.

3. The ultraviolet achromatic objective lens for a laser microfluidics processing head according to claim 1, characterized in that: The lens barrel is provided with a first spacer, a second spacer and a third spacer; The first spacer is arranged between the first biconvex positive lens and the biconcave negative lens, the second spacer is arranged between the biconcave negative lens and the second biconvex positive lens, and the third spacer is arranged between the second biconvex positive lens and the first meniscus positive lens.

4. The ultraviolet achromatic objective lens for a laser microfluidics processing head according to claim 3, characterized in that: Also includes a first pressing ring, a second pressing ring and a third pressing ring; The first pressing ring and the first spacer ring are respectively arranged on both sides of the first biconvex positive lens, the second pressing ring is arranged between the first meniscus positive lens and the second meniscus positive lens, and the third pressing ring is arranged between the second meniscus positive lens and the third meniscus positive lens; The first pressing ring, the second pressing ring and the third pressing ring are all threadedly connected to the inner wall of the lens barrel.

5. The ultraviolet achromatic objective lens for a laser microfluidics processing head according to claim 4, characterized in that: The outer circumferential surfaces of the first pressing ring, the second pressing ring and the third pressing ring are respectively provided with a first external thread, a second external thread and a third external thread, and the inner wall of the lens barrel is respectively provided with a first internal thread, a second internal thread and a third internal thread, and the first external thread, the second external thread and the third external thread are respectively threadedly matched with the first internal thread, the second internal thread and the third internal thread.

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