Femtosecond laser for ophthalmic surgery employing a resonant scanner with improved laser spot distribution uniformity

Abstract

In a femtosecond ophthalmic laser system that employs a high frequency resonant scanner to generate laser scan lines and employs an XY scanner and a Z scanner to move the scan lines in a patient's eye to perform eye surgery, a beam blocking member is placed near an internal focal plane of the optical system to block some of the beam paths in the beam paths, thereby truncating the laser scan lines at both ends. This eliminates closely spaced or overlapping laser focal spots near the ends of the scan lines. The beam blocking member has a plate-like shape with one or more apertures of different shapes or sizes, and the beam blocking member is movable in a lateral direction to different positions to block different amounts of scan lines.

Description

[0001] Cross-reference to related applications

[0002] This application claims priority to U.S. Provisional Application No. 63 / 607260, filed December 7, 2023, the contents of which are expressly incorporated herein by reference. Background Technology

[0003] This invention relates to ophthalmic laser systems, and more specifically, to femtosecond ophthalmic laser systems using a resonant scanner.

[0004] Femtosecond laser systems are used to perform laser-assisted ophthalmic surgery by creating incisions in eye tissues such as the cornea. For femtosecond lasers using very high pulse repetition rates (e.g., 5 MHz to 20 MHz), a fast scanning system is required to distribute the focal spot of the laser pulses to create a laser cutting pattern in the eye tissue. Two types of high-speed scanning systems have been described. One type of system uses a multifaceted polygonal mirror that rotates at high speed. This scanning method requires a large, high-speed motor supported by a ball-bearing rotating spindle, which can cause system vibration. Furthermore, the multifaceted polygonal mirror can introduce varying amounts of wavefront aberration into the laser beam, resulting in differences between the different scan lines produced by different faces.

[0005] Another type of scanning system uses a high-speed resonant scanning mirror to generate fast scan lines. One such system is described in jointly owned U.S. Patent Application Publications Nos. US20160374857 and US20190110926. The frequency of the resonant scanning mirror is typically between 0.5 kHz and 20 kHz, for example, between 7 kHz and 9 kHz. Different scan line lengths can be obtained by applying different voltages to the resonant scanning mirror. For example, 400 μm, 600 μm, and 900 μm scan lines can be used for different tissue incision segments. The resonant scanning mirror is a mechanical oscillator that is non-reactive, thus eliminating all external vibrations, and it has no vulnerable parts. This resonant scanning mirror has a proven long operating life of billions of continuous scan cycles (equivalent to a service life of ten years or more under normal conditions). Summary of the Invention

[0006] This invention relates to a femtosecond ophthalmic laser system employing a resonant scanner that produces improved uniformity of laser spot distribution along the scan line.

[0007] Additional features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from that description, or may be learned by practice of the invention. The objects and other advantages of the invention will be realized and obtained by means of the structures particularly pointed out in the written description, its claims, and the accompanying drawings.

[0008] To achieve the above objectives, the present invention provides an ophthalmic laser system comprising: a laser device configured to generate a pulsed laser beam having multiple laser pulses; a high-frequency scanner configured to scan the laser beam back and forth at a predefined frequency to form multiple scanning laser beams at different angles; a first set of optical elements and a second set of optical elements configured to focus the scanning laser beam through an internal focal plane located between the first set of optical elements and the second set of optical elements to form multiple external focal spots forming laser scanning lines, each set of optical elements including one or more lenses. A mirror; and a beam blocking member located near an inner focal plane, wherein the beam blocking member has a plate-like shape and defines one or more apertures; a mechanical support and moving structure configured to support and move the beam blocking member in a transverse direction perpendicular to the optical axes of the first set of optical elements and the second set of optical elements, wherein the one or more apertures of the beam blocking member are configured to block a portion of the plurality of scanning laser beams to eliminate a portion of the outer focal spot at both ends of the laser scanning line, and the beam blocking member is configured to move to different positions in the transverse direction to block different portions of the plurality of scanning laser beams.

[0009] In another aspect, the present invention provides a method implemented in an ophthalmic laser system, the method comprising: generating a pulsed laser beam having a plurality of laser pulses by a laser device; scanning the laser beam back and forth at a predefined frequency by a high-frequency scanner to form a plurality of scanning laser beams at different angles; focusing the scanning laser beams through an internal focal plane located between the first and second sets of optical elements to form a plurality of external focal spots forming a laser scanning line by means of a first set of optical elements and a second set of optical elements, each set of optical elements including one or more lenses; blocking a portion of the plurality of scanning laser beams by means of a beam blocking member located near the internal focal plane to eliminate a portion of the external focal spots at both ends of the laser scanning line, wherein the beam blocking member has a plate-like shape and defines one or more apertures; and supporting the beam blocking member in a transverse direction perpendicular to the optical axes of the first and second sets of optical elements by means of a mechanical support and a movable structure and moving the beam blocking member to different positions to block different portions of the plurality of scanning laser beams.

[0010] It should be understood that the foregoing general description and the following detailed description are merely exemplary and illustrative, and are intended to provide further explanation of the claimed invention. Attached Figure Description

[0011] Figures 1A to 1C This schematically illustrates a portion of the optical system of an ophthalmic laser system and the principle of scan line truncation (blocking).

[0012] Figure 2A and Figure 2B A portion of the optical system of an ophthalmic laser system with a wedge-shaped beam-blocking component is schematically illustrated.

[0013] Figures 3A to 3F An example of the shape of a beam-blocking component in a plan view is shown.

[0014] Figure 4 Another method for photo-induced breakage at both ends of a control scan line according to an alternative embodiment of the invention is illustrated schematically.

[0015] Figure 5 Another method for photo-induced breakage at both ends of a control scan line according to another alternative embodiment of the invention is illustrated schematically.

[0016] Figure 6 This is a block diagram illustrating a surgical ophthalmic laser system in which embodiments of the present invention can be implemented.

[0017] Figure 7 This is another illustration of a surgical ophthalmic laser system in which embodiments of the present invention can be implemented. Detailed Implementation

[0018] Figure 6 and Figure 7 An example is a surgical ophthalmic laser system in which embodiments of the present invention can be implemented. For example... Figure 6 As shown, the system 10 for forming an incision in tissue 12 of a patient's eye includes, but is not limited to: a laser 14 capable of generating a pulsed laser beam; an energy control module 16 for changing the pulse energy of the pulsed laser beam; a fast scan line motion control module 20 for generating a fast scan line of the pulsed laser beam (described in more detail later); a controller 22; and a slow scan line motion control module 28 for moving and delivering the laser scan line to the tissue 12. The controller 22 (such as a processor operating suitable control software) is operatively coupled to the fast scan line motion control module 20, the slow scan line motion control module 28, and the energy control module 16 to guide the scan line of the pulsed laser beam along a scan pattern on or within the tissue 12. In this embodiment, the system 10 also includes a beam splitter 26 and an imaging device 24 coupled to the controller 22 of a feedback control mechanism (not shown) for the pulsed laser beam. Other feedback methods may also be used. In one embodiment, the pulse pattern can be summarized in machine-readable data in the form of a treatment table on a tangible storage medium. The treatment table can be adjusted based on feedback input to controller 22 from an automatic image analysis system in response to feedback data provided from a monitoring system feedback system (not shown).

[0019] Laser 14 may include a femtosecond laser capable of providing a pulsed laser beam that can be used for optical procedures such as localized photo-induced fracturing (e.g., laser-induced optical breakdown). Localized photo-induced fracturing can be positioned on or beneath the surface of tissue or other materials to produce high-precision material processing. For example, a micro-optical scanning system can be used to scan the pulsed laser beam to create incisions in the material, form lobes in the material, form pockets within the material, form removable structures in the material, etc. The term "scanning" refers to the movement of the focus of the pulsed laser beam along a desired path or in a desired pattern.

[0020] In other embodiments, laser 14 may include a laser source configured to deliver an ultraviolet laser beam comprising a plurality of ultraviolet laser pulses capable of optically decomposing one or more intraocular targets within the eye.

[0021] While the laser system 10 can be used for photoaltering a variety of materials (e.g., organic, inorganic, or combinations thereof), it is suited for ophthalmic applications in some embodiments. In these cases, focusing optics direct a pulsed laser beam toward the eye (e.g., onto or within the cornea) to achieve plasma-mediated (e.g., non-UV) photoalblation of superficial tissues, or to direct the pulsed laser beam into the corneal stroma to achieve intrastromal photoruption of the tissue. In these embodiments, the surgical laser system 10 may also include a lens to alter the shape of the cornea (e.g., flatten or bend) before scanning the pulsed laser beam toward the eye.

[0022] Figure 7 Another exemplary diagram of the laser system 10 is shown. Figure 7Components of a laser delivery system are shown, including a portable XY scanner (or portable XY stage) 28 comprising a miniaturized femtosecond laser system. In this embodiment, system 10 uses a femtosecond oscillator or a low-energy laser based on a fiber optic oscillator. This allows the laser to be made smaller. Laser-tissue interaction is in a low-density plasma mode. An exemplary set of laser parameters for such a laser includes pulse energies in the range of 40 nJ to 100 nJ and pulse repetition rates (or “repetition rates”) in the range of 2 MHz to 40 MHz. A fast Z-scanner 25 and a resonant scanner 21 guide the laser beam to a scan line rotator 23. When used in ophthalmic procedures, system 10 also includes a patient interface design with a fixed cone nose 31 and a contact lens 32 that engages with the patient’s eye. A beam splitter may be placed inside the cone 31 of the patient interface to allow imaging of the entire eye via visualization optics. In some implementations, system 10 may use: an optics with a numerical aperture (NA) of 0.6, which will produce a full-width at half maximum (FWHM) focal spot size of 1.1 µm; and a resonant scanner 21 that produces scan lines from 0.2 mm to 1.2 mm, wherein the XY scanner scans the resonant scan lines to a 1.0 mm field of view. A prism 23 (e.g., a Duff prism or a Pekun prism, etc.) allows the resonant scan lines to rotate in any direction in the XY plane. A fast Z scanner 25 sets the incision depth. A slow scan line motion control module employs a movable XY stage 28 that carries an objective 27 with Z-scanning capability, referred to as a slow Z scanner because it is slower than the fast Z scanner 25. The movable XY stage 28 moves the objective to achieve scanning of the laser scan line in both the X and Y directions. The objective changes the depth of the laser scan line in the tissue. An energy control and auto-Z module 16 may include appropriate components to control the laser pulse energy, including attenuators, etc. It may also include an automated Z-module that uses a confocal or non-confocal imaging system to provide depth reference. The miniaturized femtosecond laser system 10 can be a benchtop system, allowing the patient to sit upright during treatment. This eliminates the need for certain opto-robotic arm mechanisms and significantly reduces the complexity, size, and weight of the laser system. Alternatively, the miniaturized laser system can be designed as a conventional femtosecond laser system in which the patient is treated while lying down.

[0023] Using the system described above, beam scanning can be achieved using a "fast scan, slow sweep" scanning scheme, also referred to herein as the fast scan line scheme. This scheme consists of two scanning mechanisms: first, using a high-frequency fast scanner (e.g., Figure 7The laser system 10 employs a resonant scanner 21 to scan the beam back and forth to produce short, fast scan lines; secondly, the fast scan lines are slowly swept by much slower X, Y, and Z scanning mechanisms (e.g., a movable XY stage 28 and an objective 27 with slow Z scanning, and a fast Z scanner 25). In some examples, the laser system 10 uses an 8 kHz (e.g., between 7 kHz and 9 kHz, or more generally, between 0.5 kHz and 20 kHz) resonant scanner 21 to produce fast scan lines of about 1 mm (e.g., between 0.9 mm and 1.1 mm, or more generally, between 0.2 mm and 1.2 mm) and a scan speed of about 25 m / sec, as well as X, Y, and Z scanning mechanisms with scan speeds (sweeping speeds) less than about 0.1 m / sec. The fast scan lines may be perpendicular to the beam propagation direction, i.e., parallel to the XY plane. The slow-scan trajectory can be any three-dimensional curve plotted by an X-scanning device, a Y-scanning device, and a Z-scanning device (e.g., an XY scanner 28 and a fast Z scanner 25). The advantage of the "fast scan, slow sweep" scanning scheme is that it uses only small-field-of-view optics (e.g., a field-of-view diameter of 1.5 mm) capable of achieving high focusing quality at a relatively low cost. Larger surgical fields of view (e.g., a field-of-view diameter of 10 mm or greater) are achieved using an XY scanner, and these fields of view are unrestricted.

[0024] In the laser system described above, due to the nature of the resonant scanning motion, the mirror angle, as a function of time, is sinusoidal. Therefore, at or near the inflection points, the scanning speed is zero or close to zero. Since the point-to-point spacing of the scanning laser spot within the eye tissue is proportional to the scanning speed, the laser spots can approach each other and overlap near the inflection points at both ends of the scan line. This high spatial density of the laser spot in the eye tissue can lead to the generation of excessive bubbles within the tissue, resulting in an undesirable opaque bubble layer and redundant laser pulse deposition in the eye.

[0025] To address this problem, embodiments of the present invention provide systems and methods for eliminating closely spaced or overlapping laser focal spots caused by resonant scanners used in femtosecond laser systems. This improvement enhances the spatial uniformity of the laser spot distribution and reduces unwanted opaque bubble layer formation, excessive bubbles, and redundant laser pulse deposition during ophthalmic surgeries such as corneal refractive surgery. Preferred embodiments of the present invention provide systems and methods for physically blocking laser spots near both ends of the resonant scan line.

[0026] Figures 1A to 1C This schematically illustrates a portion of the optical system of an ophthalmic laser system and the principle of scan line truncation (blocking). Figure 1AThe corresponding laser beam path (laser device not shown) is illustrated for a specific rotation angle of the resonant scanning mirror. This part of the optical system includes the resonant scanning mirror 41 (corresponding to...). Figure 7 The system includes a resonant scanner 21, a first set of optical elements 42, and a second set of optical elements 43. Each set of optical elements includes one or more lenses and may include part of the objective lens assembly of the laser system.

[0027] like Figure 1A As shown, the incoming laser beam (parallel beam) is reflected by the resonant scanning mirror 41 into a scanning beam at a specific angle, and is focused by the first set of optical elements 42 onto an internal focal point located on the internal focal plane P of the optical system. The diverging laser beam emitted from the internal focal point is focused by the second set of optical elements 43 into an external focal spot F, which is located within the eye tissue during eye surgery.

[0028] The first set of optical elements 42 and the second set of optical elements 43 may be located, for example, Figure 7 The fast scan line movement control module 20 and / or the movable XY stage 28 in the laser system shown are used. In one embodiment, one or more lenses of the first set of optics 42 and one or more lenses of the second set of optics 42 form a beam expander for the fast scan line movement control module 20 to generate a parallel beam; another portion of the second set of optics 43 includes an objective lens located on the movable XY stage 28, which focuses the parallel beam into an outer focal spot F.

[0029] Figure 1B The laser beam path for the full scanning range of the resonant scanning mirror 41 is shown without beam obstruction. Each scanning beam, corresponding to a specific rotation angle of the resonant scanning mirror 41, is focused by a first set of optics 42 onto an internal focal point on an internal focal plane P, and the diverging beam beyond the internal focal plane P is focused by a second set of optics 43 into an external focal spot F in the eye tissue. As the resonant mirror 41 rotates back and forth within its scanning range, the scanning beam is focused through multiple internal focal points into multiple external focal spots F, thereby forming a scanning line in the eye tissue. Higher focal spot density at the ends of the scanning line is undesirable.

[0030] Figure 1C A portion of the optical system of an ophthalmic laser system is shown, wherein a beam-blocking member 44 is placed on or near the inner focal plane P to block the peripheral region of the beam path. Therefore, while the resonant scanning mirror 41 is still scanning its full scanning angle range, the beam in the peripheral region of the inner focal plane P is blocked and cannot pass through, thus eliminating the high-density laser focal spots at both ends of the scan line.

[0031] In a preferred embodiment, the length of the blocked scan line accounts for approximately 1% to 10% at each end of the scan line.

[0032] The beam blocking member 44 should be located on or near the inner focal plane. An important design consideration is to completely block the beam, but not to allow the laser power density on the beam blocking material to be too high, causing material damage. Therefore, the beam blocking member can be located at a predetermined small distance from the inner focal plane P (in the direction of the optical axis) to reduce the power density of the laser beam incident on the beam blocking member. For example, the beam blocking member can be placed at a location where the diameter of the laser focal spot formed on the beam blocking member by the first set of optical elements 42 is between 10 μm and 20 μm, such as approximately 15 μm.

[0033] In a preferred embodiment, the beam-blocking material of the beam-blocking member 44 is a long-life material capable of withstanding high laser power densities, such as ceramics and other high-bandgap materials, or a bulk material with a high-power optical coating. Another consideration is that when blocking femtosecond laser pulses, the beam-blocking material should not deposit its own material, thus contaminating other optical components. Figure 2A An optical system with a beam-blocking member 44F is schematically illustrated, wherein the surface portion 441 (beam-blocking surface) interacting with the incoming laser beam is coated with a high-power, durable optical coating, such as a multilayer dielectric glass coating with high reflectivity, a silver metallic coating with high reflectivity, or a ceramic material. The body of the beam-blocking member 44F may be formed of glass or other suitable materials.

[0034] In some embodiments, the beam blocking member 44 is shaped and positioned such that the angle of incidence of the incoming laser beam on the beam blocking surface of the beam blocking member is reduced by the amount of reflected laser beam (which may cause laser instability) that returns to the laser device through the optical system. Figure 2B A portion of the optical system with a beam-blocking member 44G is schematically illustrated, wherein the beam-blocking surface 441 is disposed at an inclined (non-perpendicular) angle relative to the optical axis of the first set of optical elements 42. A suitable angle may depend on other parameters of the optical system. In a preferred example, the beam-blocking surface 441 is approximately 5 degrees or greater relative to the direction perpendicular to the optical axis.

[0035] Preferably, the cross-sectional shape of the beam blocking member 44 (in the cross-section through the optical axis of the optical system) is such that the edge blocking the laser beam is a tapered shape (wedge shape) terminating at the edge of a blade, so as to effectively block the beam to be blocked and keep other beams intact, such as... Figure 2A and Figure 2BAs shown (note that the coating on the beam-blocking surface is exaggerated in the accompanying drawings for emphasis). It should be noted that the wedge shape does not need to be thin; the beam-blocking member can have any wedge angle, as long as the orientation of the beam-blocking member on the non-beam-facing side avoids blocking any beam. In fact, a relatively thick wedge may be advantageous because it increases the heat capacity of the beam-blocking portion.

[0036] In some embodiments, the beam blocking member 44 is a plate-like (flat or curved) shape with one or more holes. Figures 3A to 3F Some examples of the shape of a beam-blocking member are shown in a planar view (i.e., viewed along the optical axis). Figure 3A A blocking member 44A with a rectangular aperture (slit) is shown. This blocking member can be used to generate a scan line of a fixed length determined by the length of the slit (in this view, the laser scan line extends in the horizontal direction). Figure 3C and Figure 3E Blocking members 44C and 44E, each with several rectangular apertures (slits) of different lengths, are shown for generating scan lines of different lengths. The beam blocking members can be moved, including translated and / or rotated, to select different slits for blocking, thereby adjusting the length of the resulting laser scan line.

[0037] Figure 3B A blocking member 44B with a triangular hole is shown, which is formed as a sliding variable hole. The blocking member can move up and down to select the effective length of the hole used for blocking (in this view, the laser scan line extends horizontally), thereby adjusting the length of the resulting laser scan line. The sliding variable hole may alternatively have a trapezoidal shape or other non-rectangular shape.

[0038] Figure 3D A blocking member 44D with an elliptical aperture is shown, which is formed as a rotatable aperture. The blocking member can be positioned such that the center of the aperture is at the optical axis, and rotated about the optical axis to select the effective length of the aperture used for blocking, thereby adjusting the length of the resulting laser scan line. The rotatable aperture may alternatively have a polygonal shape or other non-circular shape.

[0039] Figures 3B to 3E Each example in the examples has a fixed-size hole, where the baffle moves as a whole to select the resulting scan line length.

[0040] Figure 3F A beam-blocking member 44F is shown that uses an adjustable iris aperture similar to that in a camera. The adjustable iris aperture can be formed by multiple overlapping blades around the center of the aperture, wherein the blades can rotate to change the aperture size. The blades may be coated with...

[0041] Figures 3B to 3F The exemplary hole shapes shown are not limiting; other hole shapes or combinations of the shapes described above may be used.

[0042] In the above example, the inner edge of the hole (at least the edge used to block the laser beam) is preferably tapered to form a cutting edge in a cross-sectional view, such as... Figure 2A and Figure 2B Those shown. Furthermore, the plate of the beam-blocking member is preferably buckled or bent, such that the portion of the plate near the edge of the aperture (i.e., the portion blocking the laser beam) forms a non-perpendicular angle relative to the optical axis, such as... Figure 2B As shown.

[0043] The beam blocking member described above provides adjustability to allow the formation of laser scan lines of different lengths and can be adjusted within a short transition period (e.g., less than 150 ms) so that the transition does not significantly slow down the femtosecond laser surgery.

[0044] A mechanical support and moving structure 45 is provided to support and move the beam blocking member 44. The mechanical support and moving structure 45 can be implemented by any suitable structure, including but not limited to one or more of linear actuators, stepper motors, support rails, gears, and other suitable mechanical linkages. When using an adjustable iris aperture, the mechanical support and moving structure 45 is part of the adjustable iris aperture assembly. The mechanical support and moving structure 45 is controlled by a controller (e.g., a computer, microprocessor, etc.) of the ophthalmic laser system. The mechanical support and moving structure 45 and the controller 46 are... Figure 2B The illustration is shown in the figure.

[0045] The controller synchronously controls the laser device 14, the resonant scanner 21, the scan line rotator 23, the mechanical support and moving structure 45, the XY scanner 28, and the Z scanners 25 and 27 according to the programmed scanning pattern to scan laser scan lines in the patient's eye, thereby performing eye surgery.

[0046] Figure 4An alternative method for controlling photo-induced breakage at both ends of a scan line is schematically illustrated. In this method, a real-time feedback signal indicating the speed of the resonant scanner 41, provided by the drive electronics 411 of the resonant scanner, is used to control the laser pulse repetition rate. This is achieved by controlling the frequency of the pulse selector in the laser control board of the laser device 47. To eliminate photo-induced breakage near the ends of the scan line, the laser repetition rate is increased to a predetermined high repetition rate within a defined time interval around the inflection point of the scan line. In this state, the laser generates laser pulses with a high pulse repetition rate but a low pulse energy. The lower pulse energy ensures that at the location where the laser pulse is delivered to the tissue, the pulse energy is below the tissue's photo-induced breakage threshold (the energy at which the laser pulse begins to cause photo-induced breakage of the tissue), and therefore does not result in any tissue cutting. This eliminates photo-induced breakage near the ends of the scan line. Alternatively, the laser pulse repetition rate can be reduced to a predetermined low repetition rate within a defined time interval around the inflection point of the scan line, thus reducing the number of pulses at the ends of the scan line. Figure 4 In the diagram, the laser beams at both ends of the scan line are schematically shown with dashed lines to indicate the elimination or reduction of photo-induced cracking.

[0047] The predetermined high and low repetition rates depend on the characteristics of the laser device 47 and the optical system between the laser and the eye, and can be determined by those skilled in the art using conventional methods. Mechanisms for adjusting the laser pulse repetition rate are also known in the art.

[0048] Figure 5 An alternative method for eliminating laser pulses at both ends of a scan line is schematically illustrated. In this method, a real-time feedback signal indicating the speed of the resonant scanner 41, provided by the drive electronics 411 of the resonant scanner, is used to control an external pulse selector device (e.g., an acousto-optic module) 48, which can reject (e.g., deflect) or allow laser pulses to pass based on the speed of the resonant scanner. The pulse selector device is controlled to reject pulses within a defined time interval around the inflection point of the scan line. Figure 5 In the image, the laser beams at both ends of the scan line are schematically shown with dashed lines to indicate that they are not present.

[0049] It should be noted that other parameters of the laser scan line can also be controlled and adjusted; such adjustments, combined with the scan line truncation described above, can achieve various additional desired results. For example, by increasing or decreasing the scan amplitude of the resonant scanner, the scan line length and the overall point-to-point spacing can be increased or decreased before truncation. In this case, by using a fixed truncation aperture, the length of the truncated scan line remains constant, while the point-to-point spacing is modified and optimized to achieve tissue incisions.

[0050] It will be apparent to those skilled in the art that various modifications and variations can be made to the ophthalmic laser system of the present invention without departing from the spirit or scope of the invention. Therefore, the present invention is intended to cover various modifications and variations falling within the scope of the appended claims and their equivalents.

Claims

1. An ophthalmic laser system, comprising: A laser device configured to generate a pulsed laser beam having multiple laser pulses; A high-frequency scanner configured to scan the laser beam back and forth at a predefined frequency to form multiple scanning laser beams at different angles; A first set of optical elements and a second set of optical elements are configured to focus the scanning laser beam through an internal focal plane located between the first set of optical elements and the second set of optical elements into a plurality of external focal spots forming a laser scanning line, each set of optical elements including one or more lenses; A beam blocking member located near the inner focal plane, wherein the beam blocking member has a plate-like shape and defines one or more holes; and A mechanical support and moving structure is configured to support and move the beam blocking member in a transverse direction perpendicular to the optical axes of the first set of optical elements and the second set of optical elements. The beam blocking member has one or more holes configured to block a portion of the plurality of scanning laser beams to eliminate a portion of the outer focal spot at both ends of the laser scanning line, and the beam blocking member is configured to move to different positions in the lateral direction to block different portions of the plurality of scanning laser beams.

2. The ophthalmic laser system according to claim 1, wherein, The beam blocking member is configured to move to different positions in the lateral direction to block 1% to 10% of the plurality of scanning laser beams.

3. The ophthalmic laser system according to claim 1, wherein, The beam blocking member is located at a certain distance from the internal focal plane, such that the diameter of the laser focal spot formed by the first set of optical elements on the beam blocking member is between 10 μm and 20 μm.

4. The ophthalmic laser system according to claim 1, wherein, The beam blocking member is formed of ceramic material or coated with a high-power optical coating on the surface facing the first set of optical elements.

5. The ophthalmic laser system according to claim 1, wherein, A portion of the surface of the beam blocking member facing the first set of optical elements is positioned at a non-perpendicular angle relative to the optical axis.

6. The ophthalmic laser system according to claim 1, wherein, One or more edges of the one or more holes of the beam blocking member have a tapered shape terminating at the edge of a blade.

7. The ophthalmic laser system according to claim 1, wherein, The one or more holes are selected from the group consisting of: multiple linear slits of different lengths arranged in parallel to each other, multiple linear slits of different lengths arranged in non-parallel to each other, polygonal holes, and elliptical holes.

8. The ophthalmic laser system according to claim 1, further comprising: An XY scanner, configured to deflect the pulsed laser beam, the XY scanner being separate from the high-frequency scanner; Z-scanner, the Z-scanner being configured to modify the depth of the focal point of the pulsed laser beam; and A controller configured to control the laser device, the high-frequency scanner, the XY scanner, and the mechanical support and moving structure.

9. A method implemented in an ophthalmic laser system, comprising: A pulsed laser beam with multiple laser pulses is generated by a laser device. The laser beam is scanned back and forth at a predefined frequency using a high-frequency scanner to form multiple scanning laser beams at different angles; The scanning laser beam is focused into multiple external focal spots forming laser scanning lines by a first set of optical elements and a second set of optical elements through an internal focal plane located between the first set of optical elements and the second set of optical elements. Each set of optical elements includes one or more lenses. A portion of the plurality of scanning laser beams is blocked by a beam blocking member located near the inner focal plane to eliminate a portion of the outer focal spot at both ends of the laser scanning line, wherein the beam blocking member has a plate-like shape and defines one or more holes; as well as The beam blocking member is supported in a transverse direction perpendicular to the optical axes of the first and second sets of optical elements by means of mechanical support and a movable structure, and the beam blocking member is moved to different positions to block different parts of the plurality of scanning laser beams.

10. The method according to claim 9, wherein, The beam blocking member is configured to move to different positions in the lateral direction to block 1% to 10% of the plurality of scanning laser beams.

11. The method according to claim 9, wherein, The beam blocking member is located at a certain distance from the internal focal plane, such that the diameter of the laser focal spot formed by the first set of optical elements on the beam blocking member is between 10 μm and 20 μm.

12. The method according to claim 9, wherein, The beam blocking member is formed of ceramic material or coated with a high-power optical coating on the surface facing the first set of optical elements.

13. The method according to claim 9, wherein, A portion of the surface of the beam blocking member facing the first set of optical elements is positioned at a non-perpendicular angle relative to the optical axis.

14. The method according to claim 9, wherein, One or more edges of the one or more holes of the beam blocking member have a tapered shape terminating at the edge of a blade.

15. The method according to claim 9, wherein, The one or more holes are selected from the group consisting of: multiple linear slits of different lengths arranged in parallel to each other, multiple linear slits of different lengths arranged in non-parallel to each other, polygonal holes, and elliptical holes.

16. The method of claim 9, further comprising: The pulsed laser beam is deflected by an XY scanner; The depth of the multiple external focal spots is modified using a Z-scanner; as well as The laser device, the high-frequency scanner, the XY scanner, the Z scanner, and the mechanical support and moving structure are controlled synchronously by a controller.

17. An ophthalmic laser system, comprising: A laser device configured to generate a pulsed laser beam having multiple laser pulses; A high-frequency scanner configured to scan the laser beam back and forth at a predefined frequency to form multiple scanning laser beams at different angles; A first set of optical elements and a second set of optical elements, configured to focus the scanning laser beam through an internal focal plane located between the first and second sets of optical elements into a plurality of external focal spots forming a laser scanning line, each set of optical elements including one or more lenses; and An adjustable iris aperture, located near the internal focal plane, comprises multiple movable blades. The adjustable iris aperture is configured to block a portion of the plurality of scanning laser beams to eliminate a portion of the external focal spot at both ends of the laser scanning line, and to change the size of the aperture to block different portions of the plurality of scanning laser beams.

18. The ophthalmic laser system according to claim 17, wherein, The size of the aperture is configured to be adjusted to block 1% to 10% of the plurality of scanning laser beams.

19. The ophthalmic laser system according to claim 17, wherein, The movable blade is located at a certain distance from the internal focal plane, such that the diameter of the laser focal spot formed by the first set of optical elements on the adjustable iris aperture is between 10 μm and 20 μm.

20. The ophthalmic laser system according to claim 17, wherein, A portion of the surface of the adjustable iris aperture facing the first set of optical elements is set at a non-perpendicular angle relative to the optical axis.

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