Optical lens for laser surgery

Abstract

This invention relates to the field of optical objective lens technology specifically designed for medical applications, specifically to an optical lens for laser surgery, comprising ten lenses arranged sequentially along the optical axis from the object side to the image side: a first lens with negative optical power, a second lens with positive optical power, a third lens with positive optical power, a fourth lens with positive optical power, a fifth lens with negative optical power, a sixth lens with negative optical power, a seventh lens with positive optical power, an eighth lens with negative optical power, a ninth lens with negative optical power, and a tenth lens with positive optical power. This invention solves the problem of low energy density in the prior art.

Description

Technical Field

[0001] This invention relates to the field of optical objective technology specifically designed for medical applications, and more particularly, to an optical lens for laser surgery. Background Technology

[0002] Femtosecond lasers are lasers emitted in pulses with durations on the order of femtoseconds, representing the shortest pulses achievable by humans under experimental conditions. Femtosecond lasers are used in ophthalmic surgery and are hailed as "another revolution in refractive surgery" following wavefront aberration technology. Current laser surgery equipment for the human body primarily uses near-infrared lasers as its light source. However, due to the wavelength range of infrared light, the diffraction limit, according to optical principles, often results in a tendency for the energy application point of the laser spot to be relatively large, leading to low energy density. Summary of the Invention

[0003] The purpose of this application is to provide an optical lens for laser surgery that solves the problem of low energy density in the prior art.

[0004] The technical solution of this application:

[0005] This invention provides an optical lens for laser surgery, comprising ten lenses arranged sequentially along the optical axis from the object side to the image side: a first lens with negative optical power, its object side being concave and its image side being convex; a second lens with positive optical power, both its object side and image side being convex; a third lens with positive optical power, both its object side and image side being convex; a fourth lens with positive optical power, its object side being convex and its image side being concave; a fifth lens with negative optical power, its object side being convex and its image side being concave; a sixth lens with negative optical power, its object side being concave and its image side being convex; a seventh lens with positive optical power, its object side being convex and its image side being planar; an eighth lens with negative optical power, its object side being planar and its image side being concave; a ninth lens with negative optical power, its object side being convex and its image side being concave; and a tenth lens with positive optical power, its object side being convex and its image side being concave.

[0006] Preferably, the effective focal length of the optical lens is 62.5mm.

[0007] Preferably, the system f-number of the optical lens is 1.25.

[0008] Preferably, the entrance pupil diameter of the optical lens is 50mm.

[0009] Preferably, the total optical length of the optical lens is 160mm.

[0010] Preferably, the field of view of the optical lens is -4.5 to +4.5 degrees.

[0011] Preferably, the optical lens is used for a femtosecond laser with a wavelength of 1030nm.

[0012] Preferably, the scanning range of the optical lens is a circular range with a diameter of 10 mm.

[0013] The technical solution of this application has at least the following advantages and beneficial effects:

[0014] This invention provides an optical lens for laser surgery, comprising: a first lens for beam expansion within a certain range; second, third, and fourth lenses for micro-focusing of the beam; fifth and sixth lenses, through their negative focal length, generating a large amount of reverse spherical aberration, which cancels out and neutralizes the positive spherical aberration generated by the front lens; seventh and eighth lenses further converging the light by mutually focusing and neutralizing spherical aberration; and ninth and tenth lenses, using crescent-shaped lenses, comprehensively correcting astigmatism and field curvature. This optical lens enables the laser energy at the center of the laser spot to reach 80% of the total incident laser energy, achieving full utilization of laser energy, improving the precision of cutting operations, and solving the problem of low energy density in existing technologies. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the structure of an optical lens provided in an embodiment of the present invention;

[0016] Figure 2 A schematic diagram of incident light rays at a high field of view tilt angle provided in an embodiment of the present invention;

[0017] Figure 3 A schematic diagram of zero-field-of-view parallel incident light rays provided in an embodiment of the present invention;

[0018] Figure 4 A diagram showing the first field of view of an optical lens provided in an embodiment of the present invention;

[0019] Figure 5 A second field-of-view point array diagram of an optical lens provided in an embodiment of the present invention;

[0020] Figure 6 A diagram showing the third field of view of an optical lens provided in an embodiment of the present invention;

[0021] Figure 7 This is a first optical path difference curve diagram of an optical lens provided in an embodiment of the present invention;

[0022] Figure 8 The second optical path difference curve of the optical lens provided in the embodiment of the present invention;

[0023] Figure 9The third optical path difference curve of the optical lens provided in the embodiment of the present invention;

[0024] Figure 10 A circle-in energy fraction curve of an optical lens provided in an embodiment of the present invention;

[0025] Figure 11 A field curvature curve diagram of an optical lens provided in an embodiment of the present invention;

[0026] Figure 12 MTF value data diagram of an optical lens provided in an embodiment of the present invention;

[0027] Figure 13 A simplified diagram illustrating the usage of the optical lens provided in an embodiment of the present invention. Detailed Implementation

[0028] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] Example 1

[0030] Please refer to Figures 1-11 This invention provides an optical lens for laser surgery, comprising ten lenses arranged sequentially along the optical axis from the object side to the image side: a first lens E1 with negative optical power, its object side S1 being concave and its image side S2 being convex; a second lens E2 with positive optical power, its object side S3 and its image side S4 both being convex; a third lens E3 with positive optical power, its object side S5 and its image side S6 both being convex; a fourth lens E4 with positive optical power, its object side S7 being convex and its image side S8 being concave; and a fifth lens E5 with negative optical power, its object side S9 being convex. The sixth lens E6, with negative optical power, has an object-side surface S11 that is concave and an image-side surface S12 that is convex; the seventh lens E7, with positive optical power, has an object-side surface S13 that is convex and an image-side surface S14 that is flat; the eighth lens E8, with negative optical power, has an object-side surface S15 that is flat and an image-side surface S16 that is concave; the ninth lens E9, with negative optical power, has an object-side surface S17 that is convex and an image-side surface S18 that is concave; and the tenth lens E10, with positive optical power, has an object-side surface S19 that is convex and an image-side surface S20 that is concave.

[0031] It is worth noting that the first lens E1, with its negative optical power, expands the light beam within a certain range; the second lens E2, the third lens E3, and the fourth lens E4 each perform a minor focusing effect on the beam; the fifth lens E5 and the sixth lens E6, through their own negative optical power, generate a large amount of reverse spherical aberration, which cancels out and neutralizes the positive spherical aberration generated by the front lens; the seventh lens E7 and the eighth lens E8 further converge the light beam by mutually focusing and neutralizing spherical aberration; and the ninth lens E9 and the tenth lens E10, using crescent-shaped lenses, comprehensively correct astigmatism and field curvature. Existing laser surgical equipment for the human body uses lenses that act on infrared light, which produce severe coma and field curvature for light with a certain angle of inclination. The light spot produced by existing lenses also exhibits significant diffusion due to the oblique incident light. The focused spot produced by the optical lens provided in this embodiment is close to the theoretical diffraction limit range, with a spot diameter of 3 micrometers. This not only enables the spot to scan within a circular area with a diameter of 1 centimeter, but also prevents significant dispersion of the spot due to oblique incident light. Furthermore, it allows the laser energy at the center of the spot to reach 80% of the total laser incident energy, enabling full utilization of laser energy, improving the precision of cutting operations, solving the problem of low energy density in existing technologies, and also solving the problem of significant dispersion of oblique incident light in existing technologies.

[0032] It should be noted that the window lens G1 in this embodiment is specifically the bio-interface protection window lens G1 of the optical lens, and its thickness is preferably 2mm. The aperture stop ST in this embodiment is specifically an aperture stop, used to control the size of the light-receiving range of the entire optical lens.

[0033] Please refer to Figures 1-3 Existing precision focusing lenses often use aspherical lenses, which are difficult to manufacture due to their high precision and limited mass production range. The optical lens provided in this embodiment uses ten lenses. By increasing the number of lenses, aberration correction is achieved through light propagation between lenses made of the same material, providing more variables. On the other hand, the optical power required for precise light convergence is evenly distributed among the lenses, reducing the use and reliance on aspherical lenses, minimizing the lens's dependence on deformable lenses, and reducing the difficulty of manufacturing and mass production.

[0034] The lens in this optical lens can effectively scan within a centimeter range through a relatively large deflection angle. This means the optical lens provided in this embodiment can also serve as a special laser lithography focusing lens, making its application primarily focused on applications where laser light propagates freely in space and converges inside a transparent object with a certain refractive index, such as the cornea of ​​a biological eye. It can perform scanning and cutting operations on a plane of a certain depth on an object without damaging its surface.

[0035] All 10 lenses in the optical lens provided in this embodiment are made of C79-80 colorless and transparent borosilicate glass. The relevant parameters of each lens in the optical lens provided in this embodiment are shown in Table 1.

[0036]

[0037]

[0038] Table 1

[0039] Example 2

[0040] Based on Embodiment 1, an optical lens for laser surgery is provided, specifically: the effective focal length of the optical lens is 62.5 mm. The system f-number of the optical lens is 1.25. The entrance pupil diameter of the optical lens is 50 mm. The total optical length of the optical lens is 160 mm. The field of view of the optical lens is -4.5 to +4.5 degrees. The optical lens is used with a 1030 nm femtosecond laser. The scanning range of the optical lens is a circular area with a diameter of 10 mm.

[0041] It should be noted that the F-number of an optical system refers to the ratio of the effective focal length to the entrance pupil diameter. The total optical length of the lens described in this embodiment is the distance from the aperture stop to the protective window lens G1.

[0042] In this embodiment, S22 to S23 represent a surface simulation of the human cornea by the optical lens, indicating effective focal imaging at a depth of 0.1 mm below the corneal epithelium. The simulated human cornea has a refractive index of approximately 1.376 and an Abelian number of 55.

[0043] Existing lens assemblies for planar scanning offer a wide scanning range and minimal aberrations even with large tilt angles. However, these lens assemblies suffer from large converging spots and excessive depth of field. Given the high precision requirements of ophthalmic surgery, existing planar scanning lens assemblies cannot be directly applied to ophthalmic procedures. The optical lens provided in this embodiment is used for laser converging in femtosecond laser refractive surgery. The converged laser spot is designed to be as small as possible to minimize the depth of field, thereby improving surgical precision and reducing laser power usage.

[0044] Please refer to the details. Figures 4-6The point plots for fields of view 1, 2, and 3 were obtained with a scaling factor of 20 and the centroid as the reference. The data in the figures show that the diffraction-limited size of the light spot is 1.571 micrometers. When the beam is incident at no tilt angle, its image plane height is also centered. The effective energy spot radius is 0.326 micrometers, and the geometric radius is 0.464 micrometers. Each figure shows the image plane height and the effective energy spot radius and geometric radius at each point when the beam is incident at different tilt angles. The maximum tilt angle is 4.5 degrees, the image plane height is 4.85 millimeters, and the effective energy spot radius is 1.721 micrometers. Table 2 shows the RMS radius and GEO radius parameters for the point plots for fields of view 1, 2, and 3.

[0045] Field of view Number One No. 2 No. 3 RMS radius 0.326 0.677 1.721 GEO radius 0.464 2.539 5.551

[0046] Table 2

[0047] Please refer to Figures 7-9 As shown in the data, the wavefront aberrations in each field of view do not exceed one wavelength. This means that wavefront aberrations exceeding one wavelength would cause mutually canceling interference effects, impacting the experiment. Specifically, wavefront aberrations less than one wavelength improve the uniformity of laser beam energy and reduce internal interference. It should be noted that... Figures 7-9 The optical path difference curves shown were all generated with a maximum scaling factor of ±1 wave.

[0048] Please refer to Figure 10 As shown in the figure, under low to medium field of view, the effective laser energy reaches 80% within a 1.5-micrometer radius centered on the center of the spot. The energy within a 1.5-micrometer radius centered on the center of the outermost edge of the scanning range also reaches 60%, indicating that the optical lens provided in this embodiment has good energy utilization.

[0049] Please refer to Figure 11 The parameters obtained from the field curvature curve are: the maximum field of view is 4.5000 degrees, the legend corresponds to the wavelength, and the data in the figure shows that the optical lens provided in this embodiment has a sagittal field curvature of 0.0066 mm and a meridional field curvature of 0.0067 mm. The final field curvature size is 0.0066 mm, which means that the focal plane of the maximum field of view is only 6 micrometers different from the focal plane of the center.

[0050] Please refer to Figure 12 The data in the figure shows that when the spatial frequency of all incident angles reaches 200 line pairs per millimeter, it is greater than 0.5. When the lens resolution reaches 200 line pairs per millimeter, it can distinguish line pairs with a spacing of five micrometers.

[0051] Existing optical focusing lenses are primarily designed for applications involving observation or application to the surface of objects. In the application scenario of the optical lens provided in this embodiment, the laser beam needs to penetrate through a glass slide and a biological cornea of ​​a certain thickness to act within the cornea. Existing optical focusing lenses, due to their application point within the cornea, generate additional aberrations, leading to an enlarged beam spot and other issues, making them unsuitable for ophthalmic surgery.

[0052] Please refer to Figure 13 Since the optical lens provided in this embodiment is used on a femtosecond laser, too many lenses will produce group velocity delay dispersion, causing broadening of the femtosecond laser and reducing its characteristic high pulse energy. Therefore, in use, negative dispersion broadening of the laser beam is required before it passes through the lens to neutralize the positive dispersion effect produced by the lens.

[0053] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An optical lens for laser surgery, characterized in that, There are ten lenses in total, arranged along the optical axis from the object side to the image side as follows: The first lens with negative optical power has a concave object side and a convex image side. The second lens with positive optical power has convex surfaces for both its object side and its image side. A third lens with positive optical power has both its object-side surface and its image-side surface as convex surfaces. The fourth lens with positive optical power has a convex object side and a concave image side. The fifth lens with negative optical power has a convex object side and a concave image side. The sixth lens with negative optical power has a concave object side and a convex image side. The seventh lens with positive optical power has a convex object-side surface and a flat image-side surface; The eighth lens has a negative optical power, with a flat object side and a concave image side. The ninth lens with negative optical power has a convex object side and a concave image side. The tenth lens has positive optical power, with a convex object side and a concave image side.

2. The optical lens for laser surgery according to claim 1, characterized in that, The effective focal length of the optical lens is 62.5mm.

3. An optical lens for laser surgery according to claim 1, characterized in that, The system f-number of the optical lens is 1.

25.

4. An optical lens for laser surgery according to claim 1, characterized in that, The entrance pupil diameter of the optical lens is 50mm.

5. An optical lens for laser surgery according to claim 1, characterized in that, The total optical length of the optical lens is 160mm.

6. An optical lens for laser surgery according to claim 1, characterized in that, The field of view of the optical lens is -4.5 to +4.5 degrees.

7. An optical lens for laser surgery according to claim 1, characterized in that, The optical lens is used for a 1030nm femtosecond laser.

8. An optical lens for laser surgery according to claim 7, characterized in that, The scanning range of the optical lens is a circular area with a diameter of 10mm.

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