Focusing optical lens for laser refractive surgery

Abstract

The invention discloses a focusing optical lens for laser refractive surgery, which comprises a lens body, a first lens, a second lens, a third lens, a fourth lens, a fifth lens and a sixth lens are sequentially arranged in the lens body from an object plane to an image plane of an optical axis, the first lens has negative focal power, the object side surface of the first lens is a concave surface, and the image side surface of the first lens is a plane; the second lens has positive focal power, the object side surface of the second lens is a plane, and the image side surface is a convex surface; the third lens has positive focal power, the object side surface is a convex surface, and the image side surface of the third lens is a plane; the fourth lens has positive focal power, the object side surface of the fourth lens is a convex surface, and the image side surface is a plane; the fifth lens has negative focal power, the object side surface of the fifth lens is a concave surface, and the image side surface of the fifth lens is a plane; the sixth lens has positive focal power, the object side surface of the sixth lens is a plane, and the image side surface of the sixth lens is a convex surface. The structure is simple, the layout is reasonable, the uniformity of laser beam energy is improved, the energy density is larger, and focusing light spots are smaller.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of optical lenses, in particular to a focusing optical lens for laser refractive surgery. BACKGROUND

[0002] In the medical field, femtosecond laser can be used as an ultra-precise surgical knife and has been successfully applied in the field of ophthalmology, used for making corneal flaps in excimer laser treatment of myopia, and other corneal surgeries. In the process of performing corneal refractive surgery, the focusing spot of the laser needs to be as small as possible, and the laser has a very short action time and a very high instantaneous power. Femtosecond laser is a new type of laser source with the advantages of high power, high precision, and no damage to tissues. It has gradually become an important laser source for ophthalmic surgery, especially in the treatment of refractive and cataract. However, the existing optical lens has the problem of uneven distribution of beam energy when transmitting femtosecond laser. This leads to a smaller energy density of the laser when acting on the ocular tissues, and a larger focusing spot. This not only affects the precision and efficiency of the surgery, but also may cause unnecessary damage to the surrounding tissues due to uneven energy distribution, thereby affecting the surgical effect and postoperative recovery of the patient. Therefore, developing more advanced optical lenses to improve the beam energy distribution has become an important direction to improve the quality of femtosecond laser ophthalmic surgery. SUMMARY

[0003] In view of the shortcomings of the prior art, the present application provides a focusing optical lens for laser refractive surgery, which has a simple structure, a reasonable layout, improves the uniformity of laser beam energy, has a larger energy density, and has a smaller focusing spot.

[0004] To achieve the above-mentioned purpose, the present application provides a focusing optical lens for laser refractive surgery, comprising a lens body, wherein a first lens, a second lens, a third lens, a fourth lens, a fifth lens and a sixth lens are sequentially arranged along the optical axis from the object plane to the image plane in the lens body, the first lens has a negative focal power, the object side surface of the first lens is a concave surface, and the image side surface of the first lens is a plane; the second lens has a positive focal power, the object side surface of the second lens is a plane, and the image side surface of the second lens is a convex surface; the third lens has a positive focal power, the object side surface of the third lens is a convex surface, and the image side surface of the third lens is a plane; the fourth lens has a positive focal power, the object side surface of the fourth lens is a convex surface, and the image side surface of the fourth lens is a plane; the fifth lens has a negative focal power, the object side surface of the fifth lens is a concave surface, and the image side surface of the fifth lens is a plane; and the sixth lens has a positive focal power, the object side surface of the sixth lens is a plane, and the image side surface of the sixth lens is a convex surface.

[0005] The beneficial effect of this arrangement is that, with this arrangement, the first lens with negative optical power, in conjunction with the concave object side and the flat image side, can evenly expand the incident light within a specific range, laying a stable beam foundation for the subsequent focusing link and avoiding the energy concentration deviation caused by the initial beam being too narrow. The second and third lenses, with their stepped micro-focusing of positive optical power, gradually compress the beam divergence angle, preventing the accumulation of aberrations caused by excessive single focusing, and providing a buffer for the smooth transmission of high-power lasers, ensuring the stability of the beam shape. The positive optical power design of the fourth lens is specifically designed to provide preliminary correction for aberrations such as spherical aberration generated in the previous link. By precisely matching the curvature of the surface, it offsets the focusing deviation between the edge light and the center light, clearing the way for subsequent fine control. The fifth lens uses negative optical power to actively introduce controllable aberrations, forming a complementary offset mechanism with the previous aberrations, and optimizing the overall aberration balance by "correcting aberrations with differences", creating conditions for the final high-precision focusing. The sixth lens, with its positive refractive power, completes the final convergence of the light beam. Combining the flat object-side and convex image-side morphologies, it provides secondary correction for the system's accumulated aberrations, ensuring a consistent beam focusing path. Through the synergistic effect of these lenses, combined with the final calibration of the window mirror, the laser spot is stably focused. Not only does the central energy account for 80% of the total incident energy, ensuring the required energy density for surgery, but the diffuse spot radius is also controlled within the ultra-fine range of 3.26μm. This significantly improves the precision and safety of laser cutting, providing reliable optical support for critical surgical procedures such as corneal flap creation. Furthermore, the optimal spacing between the lenses ensures high image quality and excellent stability. This helps adjust the optical path of the lens assembly, reducing aberrations such as high-order spherical aberration and coma, thereby improving image quality. This allows sufficient space for light to expand between the lenses, helping to maintain image clarity and enhance the performance and reliability of the optical system.

[0006] As a further configuration of the present invention, the entrance pupil diameter of the mirror is 20 mm, the working wavelength of the mirror is 1.03 um, the F number of the mirror is 2.6, the field of view angle of the mirror is -5°~+5°, and the effective focal length of the mirror is 52 mm.

[0007] The beneficial effects of such a setting are: reasonable structural arrangement, ensuring the use effect of the lens, ensuring the convergence effect of laser energy, improving the use reliability of the structure, and having a good use effect.

[0008] As a further configuration of the present invention, the first lens, the second lens, the third lens, the fifth lens, and the sixth lens are all spherical lenses, and the fourth lens is an even-order aspherical lens.

[0009] The beneficial effect of such an arrangement is that: in this way, the synergistic advantages of spherical and aspherical lenses can be achieved. The first three lenses and the fifth and sixth lenses are spherical lenses, which are easy to process and have low cost, and can complete the basic beam expansion, focusing and initial aberration control. The fourth lens adopts an even aspherical lens, which can accurately correct the spherical aberration and other aberrations generated in the previous steps. Its special curved surface can make the light rays of different angles focus more consistently, improving the beam quality. With such a combination, while ensuring the stability of the basic optical function, the high-precision correction capability of the aspherical lens is used to further optimize the spot focusing effect and enhance the system performance.

[0010] As a further arrangement of the present application, the mirror body further comprises an aperture stop and a filter; the aperture stop and the filter are arranged in front of the first lens.

[0011] The beneficial effect of such an arrangement is that: by arranging the aperture stop and the filter, the quality of the incident light beam can be further optimized. The aperture stop can limit the entry of stray light into the optical system, accurately control the beam aperture, and reduce the aberration caused by the edge non-parallel light, providing a purer light beam source for the subsequent lens expansion and focusing. The filter can filter out the stray light and interfering wavelengths in the laser, ensuring that the laser wavelength entering the lens group is single and the energy is stable, avoiding additional irritation of the corneal tissue by stray light. The synergistic effect of the two can reduce the correction pressure of the previous optical elements, making the aberration optimization effect of the six-level lens group more significant, and ultimately improving the spot focusing precision and energy concentration. BRIEF DESCRIPTION OF DRAWINGS

[0012] Figure 1 The layout structure of the optical lens of the embodiment of the present application is shown in the figure; Figure 2 The diffraction spot diagram of the embodiment of the present application is shown in the figure; Figure 3 The field curvature / distortion diagram of the embodiment of the present application is shown in the figure; Figure 4 The geometric circle-in energy diagram of the embodiment of the present application is shown in the figure; Figure 5 The light fan diagram of the embodiment of the present application at 0° on the object plane is shown in the figure; Figure 6 The light fan diagram of the embodiment of the present application at 3.5° on the object plane is shown in the figure; Figure 7 The light fan diagram of the embodiment of the present application at 5° on the object plane is shown in the figure. DETAILED DESCRIPTION

[0013] The present application provides an embodiment of a focusing optical lens for laser refractive surgery, which comprises a first lens, a second lens, a third lens, a fourth lens, a fifth lens and a sixth lens. Figure 1 and Figure 7As shown, the mirror body includes first lens L1, second lens L2, third lens L3, fourth lens L4, fifth lens L5 and sixth lens L6 arranged in sequence along the optical axis from the object plane to the image plane, the first lens L1 has negative focal power, the object side of the first lens L1 is concave, and the image side of the first lens L1 is flat; the second lens L2 has positive focal power, the object side of the second lens L2 is flat, and the image side of the second lens L2 is convex; the third lens L3 has positive focal power, the object side of the third lens L3 is convex, and the image side of the third lens L3 is flat; the fourth lens L4 has positive focal power, the object side of the fourth lens L4 is convex, and the image side of the fourth lens L4 is flat; the fifth lens L5 has negative focal power, the object side of the fifth lens L5 is concave, and the image side of the fifth lens L5 is flat; the sixth lens L6 has positive focal power, the object side of the sixth lens L6 is flat, and the image side of the sixth lens L6 is convex. The beneficial effects of such arrangement are: such arrangement, the first lens L1 with negative focal power cooperates with the concave object side and the flat image side, which can uniformly expand the incident light within a certain range, laying a stable light beam foundation for subsequent focusing, avoiding the energy concentration deviation caused by the initial light beam being too narrow. The second and third lenses gradually compress the beam divergence angle by means of the stepwise micro-focusing of positive focal power, which not only prevents the accumulation of aberration caused by excessive focusing at one time, but also provides a buffer for the smooth transmission of high-power laser, ensuring the stability of the light beam shape. The positive focal power design of the fourth lens L4 is specifically aimed at correcting the spherical aberration and other aberrations generated in the previous steps. Through the precise matching of the curvature of the curved surface, the focusing deviation of the edge light and the center light is offset, clearing the way for subsequent fine control. The fifth lens L5 actively introduces controllable aberration by using negative focal power, which forms a complementary cancellation mechanism with the previous aberration, optimizes the overall aberration balance through the "aberration correction" method, and creates conditions for the final high-precision focusing. The sixth lens L6 completes the final convergence of the light beam with positive focal power, and combines the flat object side and the convex image side to perform secondary correction on the comprehensive aberration accumulated by the system, ensuring the consistency of the light beam focusing path. Through the synergistic effect of the lenses and the final calibration of the window mirror, the laser spot can be stably converged at a point, not only making the central energy account for up to 80% of the total incident energy, ensuring the energy density required for surgery, but also controlling the diffraction spot radius in the ultra-fine range of 3.26μm, greatly improving the precision and safety of laser cutting, and providing reliable optical protection for key surgical steps such as corneal flap preparation. At the same time, the distance between the lenses is reasonably designed, the imaging quality is high, and the stability is good. It can help to adjust the optical path of the lens group, reduce high-order spherical aberration, coma and other aberrations, thereby improving the imaging quality. The light has enough space to expand between the lenses, which helps to maintain the clarity of the image. The performance and reliability of the optical system are improved.

[0014] As a further arrangement of the embodiment, the mirror body entrance pupil diameter is 20mm, the working wavelength of the mirror body is 1.03um, the F number of the mirror body is 2.6, the field of view angle of the mirror body is -5°~+5°, and the effective focal length of the mirror body is 52mm. The beneficial effects of such arrangement are: reasonable structural arrangement, guaranteed lens use effect, guaranteed laser energy convergence effect, improved structural use reliability, and good use effect.

[0015] As a further arrangement of the embodiment, the first lens L1, the second lens L2, the third lens L3, the fifth lens L5, and the sixth lens L6 are all spherical lenses, and the fourth lens L4 is an even aspheric lens. The beneficial effects of such arrangement are: the arrangement can exert the synergistic advantages of spherical and aspheric lenses. The first three lenses and the fifth and sixth lenses are spherical lenses, which are easy to process and have low cost, and can complete the basic beam expansion, focusing, and initial aberration control. The fourth lens L4 adopts an even aspheric lens, which can accurately correct the spherical aberration and other aberrations generated in the previous sequence. The special surface can make the focusing of light rays at different angles more consistent, improving the beam quality. With such collocation, the basic optical function is stable, and the high-precision correction ability of the aspheric lens is used to further optimize the spot focusing effect and enhance the system performance.

[0016] As a further arrangement of the embodiment, the mirror body further comprises an aperture stop and a filter; the aperture stop and the filter are arranged in front of the first lens L1. The beneficial effects of such arrangement are: the aperture stop and the filter can further optimize the incident beam quality. The aperture stop can limit stray light from entering the optical system, accurately control the beam aperture, and reduce the aberration caused by edge non-parallel light, providing a purer beam source for the subsequent lens expansion and focusing. The filter can filter out stray light and interfering wavelengths in the laser, ensuring that the laser wavelength entering the lens group is single and the energy is stable, avoiding additional irritation of the corneal tissue by stray light. The two work together to reduce the correction pressure of the previous optical elements, making the aberration optimization effect of the six-lens group more significant, and ultimately improving the spot focusing precision and energy concentration.

[0017] The related parameters of each lens in the optical lens provided by the embodiment are shown in Table 1: The above examples are only one of the preferred specific examples of the present application, and the usual changes and substitutions made by those skilled in the art within the scope of the technical solutions of the present application are all included in the protection scope of the present application.

Claims

1. A focusing optical lens for laser refractive surgery, characterized by: The optical microscope comprises a lens body, in which a first lens, a second lens, a third lens, a fourth lens, a fifth lens and a sixth lens are sequentially arranged along the object plane to the image plane of the optical axis, the first lens having a negative optical focal length, the object side surface of the first lens being a concave surface, and the image side surface of the first lens being a plane; the second lens having a positive optical focal length, the object side surface of the second lens being a plane, and the image side surface of the second lens being a convex surface; the third lens having a positive optical focal length, the object side surface of the third lens being a convex surface, and the image side surface of the third lens being a plane; the fourth lens having a positive optical focal length, the object side surface of the fourth lens being a convex surface, and the image side surface of the fourth lens being a plane; the fifth lens having a negative optical focal length, the object side surface of the fifth lens being a concave surface, and the image side surface of the fifth lens being a plane; the sixth lens having a positive optical focal length, the object side surface of the sixth lens being a plane, and the image side surface of the sixth lens being a convex surface.

2. The focusing optical lens for laser refractive surgery according to claim 1, characterized in that: The entrance pupil diameter of the mirror is 20 mm, the working wavelength of the mirror is 1.03 um, the F number of the mirror is 2.6, the field of view angle of the mirror is -5°~+5°, and the effective focal length of the mirror is 52 mm.

3. The focusing optical lens for laser refractive surgery according to claim 1, characterized in that: The first lens, the second lens, the third lens, the fifth lens, and the sixth lens are all spherical lenses, and the fourth lens is an even-order aspherical lens.

4. The focusing optical lens for laser refractive surgery according to claim 1, characterized in that: The lens body also includes an aperture stop and a filter; the aperture stop and the filter are placed in front of the first lens.

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