A focusing optical lens for laser refractive surgery

Abstract

This invention discloses a focusing optical lens for laser refractive surgery, comprising a lens body. Within the lens body, 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. The first lens has negative optical power, with a concave object-side surface and a flat image-side surface. The second lens has positive optical power, with a flat object-side surface and a convex image-side surface. The third lens has positive optical power, with a convex object-side surface and a flat image-side surface. The fourth lens has positive optical power, with a convex object-side surface and a flat image-side surface. The fifth lens has negative optical power, with a concave object-side surface and a flat image-side surface. The sixth lens has positive optical power, with a flat object-side surface and a convex image-side surface. Its structure is simple and its layout is reasonable, improving the uniformity of laser beam energy, resulting in higher energy density and a smaller focused spot.

Description

Technical Field

[0001] This invention relates to the field of optical lens technology, and in particular to a focusing optical lens for laser refractive surgery. Background Technology

[0002] In the medical field, femtosecond lasers, used as ultra-precise surgical scalpels, have been successfully applied in ophthalmology, including creating corneal flaps in excimer laser treatment for myopia and other corneal surgeries. In femtosecond laser corneal refractive surgery, the laser spot needs to be as small as possible, with an extremely short action time and very high instantaneous power. Femtosecond lasers are a new type of laser source with advantages such as high power, high precision, and minimal tissue damage, and have gradually become an important laser source in ophthalmic surgery, playing an irreplaceable role, especially in the treatment of refractive errors and cataracts. However, existing optical lenses suffer from uneven beam energy distribution when transmitting femtosecond lasers. This results in lower energy density and a larger focused spot when the laser acts on eye tissue. This not only affects the precision and efficiency of the surgery but may also cause unnecessary damage to surrounding tissues due to uneven energy distribution, thus affecting the surgical outcome and the patient's postoperative recovery. Therefore, developing more advanced optical lenses to improve beam energy distribution has become an important direction for improving the quality of femtosecond laser ophthalmic surgery. Summary of the Invention

[0003] To address the shortcomings of existing technologies, this invention provides a focusing optical lens for laser refractive surgery. It has a simple structure and reasonable layout, which improves the uniformity of laser beam energy, increases energy density, and reduces the focused spot size.

[0004] To achieve the above objectives, the present invention provides a focusing optical lens for laser refractive surgery, comprising 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 along the optical axis from the object plane to the image plane within the lens body. The first lens has negative optical power, its object-side surface is concave, and its image-side surface is planar. The second lens has positive optical power, its object-side surface is planar, and its image-side surface is convex. The third lens has positive optical power, its object-side surface is convex, and its image-side surface is planar. The fourth lens has positive optical power, its object-side surface is convex, and its image-side surface is planar. The fifth lens has negative optical power, its object-side surface is concave, and its image-side surface is planar. The sixth lens has positive optical power, its object-side surface is planar, and its image-side surface is convex.

[0005] The beneficial effects of this setup are as follows: The first lens, with its negative optical power, works in conjunction with the concave object side and the planar image side to uniformly expand the incident light beam within a specific range, laying a stable beam foundation for subsequent focusing stages and avoiding energy concentration deviations caused by an initially narrow beam. The second and third lenses, with their positive optical power and stepwise micro-focusing, gradually compress the beam divergence angle, preventing aberration accumulation caused by excessive focusing in a single pass and providing a buffer for the smooth transmission of high-power laser light, ensuring beam shape stability. The positive optical power design of the fourth lens is specifically designed to initially correct aberrations such as spherical aberration generated in the preceding stages. Through precise matching of surface curvature, it cancels the focusing deviation between edge and center rays, clearing obstacles for subsequent fine-tuning. The fifth lens actively introduces controllable aberrations using negative optical power, forming a complementary cancellation mechanism with preceding aberrations. By "correcting aberrations with aberrations," it optimizes the overall aberration balance, creating conditions for final high-precision focusing. The sixth lens, with positive optical power, completes the final beam convergence. Combining the morphology of the planar object's side and the convex image's side, it performs secondary correction of the system's accumulated aberrations, ensuring the consistency of the beam's focusing path. Through the synergistic effect of the lenses, and with the final calibration of the window lens, the laser spot is stably converged to a single point. This not only ensures that the central energy accounts for up to 80% of the total incident energy, guaranteeing the energy density required for the surgery, but also controls the diffusion spot radius within an ultra-fine range of 3.26μm, significantly improving the precision and safety of laser cutting and providing reliable optical protection for critical surgical steps such as corneal flap creation. Simultaneously, the reasonable spacing between the lenses results in high image quality and good stability. It helps adjust the optical path of the lens group, reducing higher-order spherical aberrations, coma, and other aberrations, thereby improving image quality. It allows sufficient space for light to spread between the lenses, helping to maintain image sharpness. This improves the performance and reliability of the optical system.

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

[0007] The advantages of this design are: reasonable structural arrangement, ensuring the effectiveness of the lens, ensuring the focusing effect of laser energy, improving the reliability of the structure, and achieving good performance.

[0008] As a further feature 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 advantages of this configuration are that it leverages the synergistic benefits of spherical and aspherical lenses. The first three lenses, along with the fifth and sixth lenses, are spherical lenses, which are easy to manufacture and have low cost, enabling basic beam expansion, focusing, and initial aberration control. The fourth lens is an even-order aspherical lens, which can accurately correct aberrations such as spherical aberration generated in the previous lenses. Its special curved surface allows for more consistent focusing of light rays from different angles, improving beam quality. This combination ensures stable basic optical functions while further optimizing the beam focusing effect and enhancing system performance by utilizing the high-precision correction capabilities of the aspherical lenses.

[0010] As a further feature of the present invention, the mirror body also includes an aperture stop and a filter; the aperture stop and the filter are positioned in front of the first lens.

[0011] The beneficial effects of this setup are as follows: The aperture stop and filter further optimize the quality of the incident beam. The aperture stop limits stray light from entering the optical system, precisely controls the beam aperture, and reduces aberrations caused by non-parallel rays at the edges, providing a cleaner beam source for subsequent lens expansion and focusing. The filter removes unwanted stray light and interfering wavelengths from the laser, ensuring a single wavelength and stable energy of the laser entering the lens group, avoiding additional stimulation of the corneal tissue by stray light. The synergistic effect of these two elements reduces the corrective stress on preceding optical components, making the aberration optimization effect of the six-stage lens group more significant, ultimately improving the focusing accuracy and energy concentration of the light spot. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the layout structure of the optical lens in an embodiment of the present invention;

[0013] Figure 2 This is a diffusion pattern from an embodiment of the present invention;

[0014] Figure 3 This is a field curvature / distortion diagram from an embodiment of the present invention;

[0015] Figure 4 This is a geometric ingress energy diagram according to an embodiment of the present invention;

[0016] Figure 5 This is a ray fan pattern of the light rays at 0° on the object surface according to an embodiment of the present invention;

[0017] Figure 6 This is a ray fan pattern of the light rays at 3.5° to the object plane according to an embodiment of the present invention;

[0018] Figure 7 This is a ray fan pattern of the object at 5° to the surface, according to an embodiment of the present invention. Detailed Implementation

[0019] This invention provides an embodiment of a focusing optical lens for laser refractive surgery, for example. Figure 1 and Figure 7 As shown, the system includes a mirror body. Within the mirror body, a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, a fifth lens L5, and a sixth lens L6 are sequentially arranged along the optical axis from the object plane to the image plane. The first lens L1 has negative optical power, its object-side surface is concave, and its image-side surface is flat. The second lens L2 has positive optical power, its object-side surface is flat, and its image-side surface is convex. The third lens L3 has positive optical power. The third lens L3 has a convex object-side surface and a flat image-side surface; the fourth lens L4 has a positive optical power, with a convex object-side surface and a flat image-side surface; the fifth lens L5 has a negative optical power, with a concave object-side surface and a flat image-side surface; and the sixth lens L6 has a positive optical power, with a flat object-side surface and a convex image-side surface. The beneficial effect of this configuration is that the first lens L1, with its negative optical power and concave object-side surface and flat image-side surface, can uniformly expand the incident light beam within a specific range, laying a stable beam foundation for subsequent focusing and avoiding energy concentration deviation caused by an initially narrow beam. The second and third lenses, with their positive optical power and stepwise micro-focusing, gradually compress the beam divergence angle, preventing aberration accumulation caused by excessively strong single focusing and providing a buffer for the smooth transmission of high-power laser light, ensuring the stability of the beam shape. The fourth lens, L4, is designed with positive optical power to initially correct aberrations such as spherical aberration generated in the preceding steps. Through precise matching of surface curvature, it cancels the focusing deviation between edge and central rays, clearing obstacles for subsequent fine-tuning. The fifth lens, L5, actively introduces controllable aberrations using negative optical power, forming a complementary cancellation mechanism with preceding aberrations. This "aberration-to-correction" approach optimizes overall aberration balance, creating conditions for final high-precision focusing. The sixth lens, L6, with positive optical power, completes the final beam convergence. Combining the morphology of the planar object's side and the convex image's side, it performs secondary correction of the system's accumulated aberrations, ensuring the consistency of the beam's focusing path. Through the synergistic effect of the lenses, along with the final calibration of the window lens, the laser spot is stably converged to a single point. This not only ensures that the central energy accounts for up to 80% of the total incident energy, guaranteeing the required energy density for the surgery, but also controls the diffusion spot radius within an ultra-fine range of 3.26 μm, significantly improving the precision and safety of laser cutting and providing reliable optical support for critical surgical steps such as corneal flap creation. Meanwhile, the well-designed spacing between the lenses results in high image quality and good stability. It helps adjust the optical path of the lens group, reducing higher-order aberrations such as spherical aberration and coma, thereby improving image quality. It also allows sufficient space for light to spread between the lenses, helping to maintain image sharpness. This enhances the performance and reliability of the optical system.

[0020] As a further feature of this embodiment, the entrance pupil diameter of the lens is 20mm, the operating wavelength of the lens is 1.03µm, the F-number of the lens is 2.6, the field of view of the lens is -5° to +5°, and the effective focal length of the lens is 52mm. The advantages of this configuration are: a reasonable structural arrangement, ensuring the lens's performance, guaranteeing the laser energy focusing effect, improving the reliability of the structure, and resulting in good performance.

[0021] As a further configuration of this 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-order aspherical lens. The advantages of this configuration are that it leverages the synergistic advantages of spherical and aspherical lenses. The first three lenses, along with the fifth and sixth lenses, are spherical lenses, which are easy to manufacture and have low cost, enabling basic beam expansion, focusing, and preliminary aberration control. The fourth lens L4, being an even-order aspherical lens, can accurately correct aberrations such as spherical aberration generated in the preceding process. Its special curved surface allows for more consistent focusing of light rays from different angles, improving beam quality. This combination, while ensuring the stability of basic optical functions, further optimizes the beam focusing effect and enhances system performance by utilizing the high-precision correction capability of the aspherical lens.

[0022] As a further feature of this embodiment, the lens body also includes an aperture stop and a filter; the aperture stop and the filter are positioned in front of the first lens L1. The beneficial effects of this configuration are: the aperture stop and filter further optimize the incident beam quality; the aperture stop limits stray light from entering the optical system, precisely controls the beam aperture, reduces aberrations caused by non-parallel rays at the edges, and provides a cleaner beam source for subsequent lens expansion and focusing. The filter filters out useless stray light and interfering wavelengths in the laser, ensuring that the laser wavelength entering the lens group is singular and the energy is stable, avoiding additional stimulation of the corneal tissue by stray light. The synergistic effect of both reduces the corrective stress on preceding optical elements, making the aberration optimization effect of the six-stage lens group more significant, ultimately improving the focusing accuracy and energy concentration of the light spot.

[0023] The relevant parameters of each lens in the optical lens provided in this embodiment are shown in Table 1:

[0024]

[0025] The above examples are merely one preferred embodiment of the present invention. Ordinary variations and substitutions made by those skilled in the art within the scope of the technical solution of the present invention are all included within the protection scope of the present invention.

Claims

1. A focusing optical lens for laser refractive surgery, characterized in that: The system includes 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 optical axis from the object plane to the image plane. The first lens has negative optical power, its object-side surface is concave, and its image-side surface is flat. The second lens has positive optical power, its object-side surface is flat, and its image-side surface is convex. The third lens has positive optical power, its object-side surface is convex, and its image-side surface is flat. The fourth lens has positive optical power, its object-side surface is convex, and its image-side surface is flat. The fifth lens has negative optical power, its object-side surface is concave, and its image-side surface is flat. The sixth lens has positive optical power, its object-side surface is flat, and its image-side surface is convex.

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

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

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