Methods for characterizing laser radiation in a laser processing system, aperture devices, and laser processing systems

Abstract

The present invention relates to a method for characterizing laser radiation (24) of a laser processing system (30). The method includes a) providing an aperture device (10) having a plurality of aperture openings (14) in a working plane (300) of the laser processing system (30) such that the aperture openings (14) extend within the working plane (300). The method further includes b) scanning the laser radiation (24) over the aperture device (10) along a scanning direction (200) parallel to the working plane (300) such that the laser radiation (24) at least partially sweeps across the aperture openings (14). The method further includes c) determining the energy of the laser radiation (24) transmitted through the aperture openings (14) during the scanning process, and d) determining the extent of the laser radiation (14) based on the energy transmitted through the first aperture opening (14a) of the plurality of aperture openings (14) based on the laser radiation (24), and determining the energy parameter based on the energy transmitted through the second aperture opening (14b) of the plurality of aperture openings (14) based on the laser radiation (24). Here, the first aperture opening (14a) has a predetermined extent along the scanning direction (200), which is smaller than the average diameter of the laser radiation (24) in the working plane (300). Furthermore, the second aperture opening (14b) has an extent that is larger than the laser radiation (24) in the working plane (300) and is designed to transmit the laser radiation (24) substantially completely.

Description

Technical Field

[0001] The claimed embodiments relate to methods for characterizing laser radiation from a laser processing system, aperture devices, and, particularly, laser processing systems for ophthalmic surgery. Therefore, the embodiments relate to the field of laser processing systems for ophthalmic surgery. Background Technology

[0002] Refractive errors in the human eye are usually attributed to defects in the eye's refractive properties. For example, this refractive error can be caused by corneal distortion. In many cases, the cause of the refractive error can be eliminated or reduced by ophthalmic procedures or refractive surgery. To perform such refractive surgical treatments, such as refractive corneal surgery, an excimer laser is typically used to remove material from the cornea to be corrected, thereby creating the desired refractive effect. Needless to say, the refractive correction must be performed very precisely to achieve satisfactory treatment results, where the correction achieves the desired refractive effect.

[0003] To achieve the required precision in removing material from the cornea using laser radiation from an excimer laser, and for regulatory reasons, the actual material removal needs to be periodically characterized or inspected, material removal is induced by laser radiation. Laser radiation is typically present in pulses, so material removal by laser radiation is typically calculated as material removal per laser pulse or "bombardment" or for a predetermined pulse sequence or bombardment sequence (number of laser pulses). In the case of continuously operating lasers, material removal per irradiation duration is calculated.

[0004] This characterization of material removal is often referred to as "fluence testing" because "fluence," or fluence, is the ratio between the laser pulse energy and the effective laser spot diameter. If the material strongly absorbs the laser, it is usually the most important characteristic variable for material removal, as is the case, for example, in the case of ultraviolet light from an excimer laser, in plastics or biological tissues.

[0005] Various excimer laser systems for refractive corneal correction are known in the prior art, such as those from the applicant's systems known as MEL80 and MEL90. In these and other systems, material removal checks can be periodically performed using a so-called fluidization paper, typically composed of a dyed paperboard to which a plastic film with a metal coating of known thickness is adhered. To check for material removal, a predetermined bombardment pattern is applied to the fluidization paper, wherein a specific number of pulses or bombardments, i.e., a specific bombardment ratio, is applied to different test sites on the fluidization paper. The resulting material removal on the corresponding test sites of the fluidization paper is then visually inspected, wherein for some predetermined bombardment sequences at or within the test sites, the metal-coated plastic film remains, while in other bombardment sequences, such as test sites with higher bombardment numbers corresponding to +4% flow rate, the metal-coated plastic film has been partially removed. In the test area where at least part of the metal-coated plastic film has been removed, the dyed cardboard arranged beneath the original metal-plastic film is at least partially visible. It is then inspected visually by the operator.

[0006] An alternative method for characterizing laser radiation involves processing a lens profile in a PMMA substrate using an excimer laser, specifically by removing material from the PMMA substrate accordingly. Subsequently, complex measurements are performed on the treated PMMA substrate, measuring the actual refractive effect of the treated PMMA substrate or its lens shape and comparing it to corresponding, predetermined target values. The treatment effect can then be inferred from possible deviations, and the laser radiation characterized. However, this method requires specialized measuring instruments and is highly expensive, making daily routine checks of laser radiation using this method economically impractical or infeasible. The execution of this method also requires a high level of technical expertise, and for this reason, it is typically entrusted to trained personnel, such as service technicians, and cannot be easily performed by ordinary operators. Therefore, this method is typically performed only during initial calibration, such as during system manufacturing or initial commissioning.

[0007] Methods for determining the size of laser radiation are also known in the prior art, wherein the laser radiation scans along a path on a reference edge, as described, for example, in US 6,559,934 B1. Furthermore, US 2002 / 0198515 A1 describes a method in which a structure having a slit or reference edge for adjustment or calibration purposes is used in the treatment plane for adjusting the laser system. Additionally, WO 01 / 87199 A2 describes an apparatus and method for measuring the energy and / or position of pulsed laser radiation, wherein the laser radiation is temporarily redirected onto a sensor.

[0008] In cases involving invisible processing lasers, such as those emitted in the ultraviolet or infrared spectral range, an additional aiming laser is typically required. The aiming laser must emit within the visible spectrum, and for laser safety reasons, it usually has a much lower intensity in the working plane than the processing laser. The aiming laser is typically spatially superimposed sufficiently well with the processing laser in the working plane, and this spatial superposition must be checked periodically for safety reasons. This superposition is usually visually checked by a physician, for example, by examining the superposition of the structures marked by the processing laser and the aiming laser on volumetric paper. Summary of the Invention

[0009] Therefore, the object of the present invention is to provide a method and an apparatus for reliably characterizing or inspecting processed lasers in a working plane, and to provide the possibility of automation. Here, characterization should in particular include flux and / or spatial calibration of laser parameters in the working plane.

[0010] Furthermore, the objective is to provide a method and apparatus for inspecting the superposition of processing lasers and aiming lasers and to provide the feasibility of automation.

[0011] The objective is achieved through the described embodiments. These embodiments relate to methods for characterizing laser radiation of a laser processing system, aperture devices, laser processing systems, devices for corneal refractive correction, excimer lasers, and devices for corneal refractive correction, having the features of the respective independent claims. Optional embodiments are described in the dependent claims and the specification.

[0012] The first embodiment relates to a method for characterizing laser radiation in a laser processing system. The method includes a) providing an aperture device having a plurality of aperture openings, i.e., two or more aperture openings, in a working plane of the laser processing system, such that the aperture openings extend within the working plane. The method further includes b) scanning laser radiation over the aperture device along a scanning direction parallel to the working plane, such that the laser radiation sequentially at least partially sweeps through at least two of the aperture openings. Furthermore, the method includes c) determining the energy of the laser radiation transmitted through the aperture openings during the scanning process, and d) determining the extent of the laser radiation along the scanning direction based on the determined energy transmitted through a first aperture opening of the plurality of aperture openings, and determining an energy parameter based on the determined energy transmitted through a second aperture opening of the plurality of aperture openings. Here, the first aperture opening has a predetermined extent along the scanning direction, which is smaller than the average diameter of the laser radiation in the working plane. Furthermore, the second aperture opening has an extent in the working plane that is larger than the laser radiation in the working plane and is designed to transmit the laser radiation substantially completely. Optionally, the laser radiation is used to scan the aperture opening, such that at most one aperture opening is scanned by the laser radiation at each time point, but multiple aperture openings are not scanned by the laser radiation simultaneously.

[0013] Another embodiment relates to an aperture device for characterizing laser radiation from a laser processing system, wherein the aperture device is arranged in the working plane of the laser processing system and includes an aperture having a plurality of aperture openings. Here, the aperture device includes: a first aperture opening having a predetermined extension along the scanning direction of the laser radiation that is smaller than the average diameter of the laser radiation to be inspected in the working plane; and a second aperture opening having a larger extension than the laser radiation to be inspected and designed to transmit the laser radiation substantially completely. Furthermore, the aperture device includes at least one photodetector arranged such that at least a portion of the laser radiation transmitted through the aperture openings in the working plane can be detected by means of the photodetector.

[0014] Another embodiment relates to a laser processing system for processing an object in a working plane by means of laser radiation. The laser processing system includes: a laser source for providing laser radiation; a deflection device capable of moving the laser radiation within the working plane perpendicular to the propagation direction of the laser radiation; and an aperture device according to an alternative embodiment. Here, the aperture device can be arranged in the laser processing system to characterize the laser radiation, such that the aperture opening is arranged in the working plane.

[0015] Another embodiment relates to a method for characterizing laser radiation in a laser processing system. The method includes: (a) providing an aperture device having an aperture opening in a working plane of the laser processing system, such that the aperture opening extends within the working plane, wherein the aperture device has at least two opening edges that are opposite each other at a predetermined distance and extend in parallel, the opening edges defining the aperture opening, and the aperture opening being larger than the laser radiation in the working plane and designed to transmit the laser radiation substantially completely. Furthermore, the method includes: (b) scanning the laser radiation over the aperture device along a scanning direction parallel to the working plane, such that the laser radiation sequentially and at least partially sweeps across a first opening edge of the two opening edges, the aperture opening, and a second opening edge of the two opening edges in time; and (c) determining the energy of the laser radiation transmitted through the aperture opening during the scanning process. Furthermore, the method includes (d) determining the spread of laser radiation along the scanning direction based on the curve of the energy transmitted when the laser radiation sweeps across the first opening edge and / or the second opening edge, and determining the energy parameters of the laser radiation transmitted substantially entirely through the aperture opening, and (e) determining the adjustment parameters of the laser processing system based on the laser radiation sweeping across the opening edges arranged at predetermined intervals.

[0016] Another embodiment relates to a method for characterizing laser radiation in a laser processing system. This other embodiment may optionally include the first embodiment. The method includes: determining energy parameters of the laser radiation. Furthermore, the method includes providing a calibration device in the working plane of the laser processing system, applying laser radiation to the calibration device under the same conditions as processing an object using laser radiation, and determining calibration parameters in the working plane by means of the calibration device. Furthermore, the method includes providing a calibration device in a control plane outside the working plane and deflecting the laser radiation such that laser radiation is applied to the calibration device in the control plane; and determining control parameters by means of the calibration device in the control plane. Furthermore, the method includes determining a deviation coefficient characterizing the deviation between the calibration parameters and the control parameters, and characterizing the laser radiation using the deviation coefficient by means of the calibration device in the control plane.

[0017] Another embodiment relates to a laser processing system for processing an object by means of laser radiation. The laser processing system includes an energy sensor designed to determine energy parameters of the laser radiation. Furthermore, the laser processing system includes a calibration device optionally arranged within a working plane of the laser processing system and subject to laser radiation, and also arranged within a control plane outside the working plane and subject to laser radiation; and a deflection element arranged in the radiation path of the laser radiation such that the deflection element deflects the laser radiation aligned to the working plane into the control plane. Here, the laser processing system is configured to: arrange the calibration device in the working plane and determine calibration parameters; arrange the calibration device in the control plane and determine control parameters; determine a deviation coefficient characterizing the deviation between the calibration parameters and the control parameters; and characterize the laser radiation on the control plane using the energy parameters and the deviation coefficient by means of the calibration device.

[0018] Another embodiment relates to a method for characterizing laser radiation, which can be used alternatively or in combination with the first embodiment described above, and can also be part of another embodiment of a method for characterizing laser radiation. The method includes applying laser radiation to a test object such that the laser radiation removes a portion of the material of the test object at a test site. Furthermore, the method includes determining the change in thickness of the test object at the test site due to the application of laser radiation.

[0019] Another embodiment relates to an apparatus for characterizing laser radiation. Here, the apparatus has a test object holder designed to provide a test object for applying laser radiation, such that a portion of the material of the test object can be removed at a test site by means of the laser radiation. Furthermore, the apparatus has a measuring device configured to determine the change in thickness of the test object at the test site caused by the applied laser radiation.

[0020] Another embodiment relates to an excimer laser that includes, according to an alternative embodiment, a device for characterizing laser radiation.

[0021] Another embodiment relates to a device for refractive corneal correction, which includes an excimer laser according to a preferred embodiment and / or a device for characterizing laser radiation according to a preferred embodiment.

[0022] Here, laser radiation is radiation emitted by a laser, optionally an excimer laser. Laser radiation does not necessarily have continuous linear or continuous wave radiation, but can also exist in a pulsed manner. Furthermore, laser radiation can also be characterized as collimated, and / or convergent, and / or divergent. Optionally, the laser radiation has electromagnetic radiation in the ultraviolet spectral range. Also optionally, the laser radiation has a center wavelength of approximately 193 nm. Optionally, the laser radiation is configured for corneal refractive correction and is optionally provided by an excimer laser. Particularly optionally, the laser radiation is provided by an ArF excimer laser. Here, the working laser radiation of the laser processing system is referred to as laser radiation. In addition to laser radiation, i.e., working laser radiation, according to optional embodiments, the laser processing system can also provide targeting laser radiation, which has lower energy and whose optical spectrum is optionally at least partially in the visible spectral range. However, it is always referred to as targeting laser radiation in distinction from laser radiation.

[0023] Characterization of laser radiation may optionally include characterization of the laser radiation profile and / or radiation size. Characterization may also optionally include characterization of energy (e.g., pulse energy and / or peak power and / or average power), and / or characterization of the energy of a predetermined sequence or number of pulses, and / or characterization of intensity and / or fluence (particularly in the working plane) and / or characterization of the material removal thereby achievable. Characterization may also optionally include characterization of the laser radiation focus, i.e., for example, the shape and / or profile and / or intensity of the focused laser radiation.

[0024] Here, an aperture device is a device or apparatus comprising an aperture having multiple aperture openings. For example, the aperture can be constructed in a planar shape, and the aperture openings can be constructed as recesses within the aperture. Here, apart from the aperture openings, the aperture is opaque to laser radiation and is optionally constructed such that the aperture will not be damaged by the application of laser radiation, which would compromise its opacity to laser radiation. The aperture openings are optionally completely transparent to laser radiation and are particularly optionally constructed as recesses or holes within the aperture. The aperture can be constructed as a single piece or in multiple pieces. In addition to the aperture, the aperture device can also have other elements. For example, the aperture device can have photodetectors and / or other elements, which can form, for example, fixed components of the aperture device.

[0025] Here, the working plane is the plane on which the laser processing system applies laser radiation to the object being processed, such as an eye. In other words, the laser processing system can be designed to: process the object being processed with laser radiation in the working plane and / or mark the incident point on the object being processed with aiming laser radiation. For example, the laser radiation and / or aiming laser radiation can be focused by the laser processing system onto the working plane. However, the working plane does not necessarily have to be a plane in a mathematical sense, although this can be the case according to some alternative embodiments. According to other alternative embodiments, the working plane can also be constructed as a curved surface, thereby representing a surface extending in three-dimensional space.

[0026] Here, the scanning of laser radiation along the scanning direction can optionally involve deflection of the laser radiation, causing the intersection of the laser radiation and the working plane to shift or move within the working plane along the scanning direction. For example, scanning can be accomplished using a deflection device that can move the laser radiation within a predetermined range within the working plane. Here, the scanning direction does not necessarily extend in a straight line, but can also follow a curved path or even a free-form curve. The scanning direction can also extend in multiple dimensions. Optionally, the scanning direction extends in a straight line in multiple scanning segments, wherein the scanning directions of each scanning segment can be different from each other, and can even be perpendicular to each other. Particularly optional, the scanning direction extends discontinuously and abruptly between processing points, so as to position the processing points for sequential processing as far apart as possible to reduce the thermal load on the processed object. However, optionally, the scanning direction extends entirely within the working plane.

[0027] According to another alternative embodiment, the scanning of the laser radiation above the aperture device can be achieved by optionally moving the aperture device vertically relative to the laser radiation. This provides the advantage that the laser radiation does not need to be deflected for characterization. Here, scanning the laser radiation above the aperture device along a scanning direction parallel to the working plane means that the laser radiation is deflected in one or more directions perpendicular to the optical axis of the laser radiation. Optionally, the distance between the working plane and the optical element (e.g., the scanning mirror) causing the deflection is large enough that possible projection effects are negligible when the laser radiation is deflected, i.e., during scanning, and especially for determining the flux.

[0028] Here, the fact that the laser radiation at least partially sweeps across the aperture opening means that not all of the aperture opening needs to be swept by the laser radiation. This also means that, optionally, the entire corresponding aperture opening does not need to be swept by the laser radiation, but the aperture opening can also have areas that are not swept by the laser radiation. For example, according to an alternative embodiment, the first aperture opening can be constructed in a slit shape, wherein the width of the slit is smaller than the laser radiation in the working plane, and the length of the slit is greater than the spread of the laser radiation in the working plane. Here, for example, such a slit-shaped aperture opening can be swept by the laser radiation such that the laser radiation sweeps across its entire width but not its entire length.

[0029] Here, the average diameter is optionally full width at half maximum (FWHM). Here, the extension of the laser radiation is optionally a radiation surface that, assuming a Gaussian radiation profile, contains 99.5% of the laser radiation power or energy. Here, the second aperture opening substantially completely transmits the laser radiation, meaning that the power or energy not transmitted by the second aperture opening, or blocked, does not exceed 0.5% of the total power or energy. This achieves that the attenuation of the laser radiation through the second aperture opening is negligible and optionally lower than the typical sensor signal-to-noise ratio.

[0030] Here, the energy parameters determined within the scope of this method may optionally be parameters characterizing the energy and / or power of the laser radiation. Optionally, the intensity and / or flux of the laser radiation in the working plane can be determined based on the specific spread of the laser radiation.

[0031] Optionally, the energy parameter characterizes the energy of the laser radiation and / or the power of the laser radiation and / or the energy of the laser pulse and / or the energy of a series of laser pulses.

[0032] Here, the calibration parameters determined within the scope of this method are parameters that enable the determination and / or expectation of material removal by laser radiation, particularly corneal removal when applied to the eye to be treated. The calibration parameters may specifically include, or achieve, the flux and / or intensity of the laser radiation in the working plane. Control parameters may optionally correspond to the calibration parameters, provided that the control parameters characterize the laser radiation in the control plane. Particularly optionally, the calibration parameters and control parameters can be directly compared to each other, such that the deviation coefficient may optionally represent a dimensionless variable that quantifies, on the one hand, the difference in value or absolute value or magnitude between the calibration parameters and on the other hand, the difference in value or absolute value or magnitude between the control parameters. Optionally, the determination of the calibration parameters includes determining the flux and / or intensity of the laser radiation in the working plane, wherein the determination of the control parameters includes determining the flux and / or intensity of the laser radiation in the control plane.

[0033] Here, the control plane is a plane in which control parameters are derived by means of a calibration device. Optionally, the control parameters in the control plane are derived in the same manner as the calibration parameters in the working plane. The control plane is arranged such that the calibration device can be positioned in the control plane only when the patient assumes the treatment position and the patient's eye is positioned in the working plane. Therefore, optionally, the control plane is arranged and / or the calibration device is provided in the control plane such that there is no spatial overlap between the calibration device provided in the control plane and the object being processed arranged in the working plane. Particularly optionally, the control plane is at least partially arranged within the laser processing system and / or the calibration device is arranged within the laser processing system when provided in the control plane. This provides the advantage of allowing the laser processing system to be constructed in a particularly compact manner.

[0034] The test object may optionally be a solid element from which material can be removed by laser ablation via laser radiation. Further optionally, the test object is designed to at least partially absorb the laser radiation so that ablation of the material is achieved by the absorbed energy incident in the form of laser radiation. In other words, the test object may optionally be made of an ultraviolet-ablable medium. Further optionally, the test object is made of a material that is at least partially transparent and optionally almost completely transparent to electromagnetic radiation in the visible and / or infrared spectral range. This enables the use of optical measurement methods based on visible and / or infrared wavelengths to determine changes in the thickness of the test object. Further optionally, the test object is constructed to have a surface that can be detected by means of a confocal colorimetric sensor, particularly after the surface has been treated with a UV laser.

[0035] Optionally, the test subject is at least partially made of polymethyl methacrylate (PMMA), which has a very high optical density in the ultraviolet spectral range, particularly at 193 nm, and high transparency, especially in the visible spectral range. Alternatively to or in addition to solid test subjects, test subjects having or composed of biological tissue, such as donor corneal portions and similar substances such as gels, can also be used. Particularly advantageous is that the test subject does not need to be moved or only moved very little between laser processing and measurement, and measurements can be performed very close in time after the application of laser irradiation, thus greatly reducing or eliminating the risk of shape changes in the test subject between processing and measurement.

[0036] Optionally, the determination of the thickness variation of the test object is performed in a constant test object position and / or orientation, such as when laser radiation is applied to the test object. In other words, optionally, the test object remains substantially still between the application of laser radiation and the determination of the thickness variation. "Substantially still" here means that the test object does not move relative to the laser radiation and / or relative to the measuring device, or the possible movement is so small that the determination of the thickness variation at the test site is not impaired. This also provides the advantage that the determination of the thickness variation can be reliably performed at the test site where laser radiation has been applied. Furthermore, it provides the advantage that test objects with unstable shapes and / or whose positionability cannot be reliably reproduced can also be reliably used.

[0037] Applying laser radiation to a test object may include exposing the test object to laser radiation such that the laser radiation is incident on the test object. Applying laser radiation to the test object may optionally be done for a specific irradiation duration, particularly when using a continuous-wave laser, but may also be done with a specific number of laser pulses when using a pulsed laser. It goes without saying that there is a relationship and / or correlation between material removal and irradiation duration or number of laser pulses when applying laser radiation to a test object. Optionally, the application may be performed in the same manner as when applying laser radiation to the cornea during corneal refractive correction, particularly with regard to environmental parameters such as UV-absorbing substances in the ambient air, i.e., air humidity, and / or radiation diameter and / or radiation power or pulse energy. Alternatively or additionally, the application to the test object may also be achieved with other radiation diameters and / or power and / or pulse energies.

[0038] Here, the test site is specifically a portion of the test object and / or on the test object that can be located on the surface of the test object or within the test object, i.e., within a volumetric region of the test object. The test site is a portion to which laser radiation is applied and where material removal occurs accordingly. Before laser radiation is applied to the test site, the test site can optionally correspond to an unchanged test object and be indistinguishable from other portions of the test object.

[0039] The advantage of this implementation is that the spread of laser radiation and the power or energy of the laser radiation can be measured directly in the working plane. This has the advantage that, without erroneous assumptions or influences, the flux of the laser radiation can be determined directly in the working plane, i.e., at the location where the laser radiation is applied to the object being processed, and in this way, particularly reliable characterization and possible adaptation of the laser radiation can be achieved. Therefore, this provides advantageous feasibility, for example, directly determining the flux, without, for example, having to perform energy or power measurements at other locations in the laser processing system and without having to determine the spread of the laser radiation outside the working plane, so as not to indirectly infer the flux through or inappropriate assumptions. It also provides the feasibility of optionally checking the precise location of the laser radiation and aiming at the precise location of the laser radiation, and optionally checking their superposition in the working plane. Therefore, the reliability of the characterization can be improved by this implementation.

[0040] Furthermore, the implementation provides the advantage that the characterization of laser radiation, particularly the determination of laser radiation flux, and the calibration of offset devices (e.g., scanners) can all be achieved using an aperture device. In other words, the implementation provides the advantage that multiple characterizations or inspections can be performed using an aperture device in the working plane, for which different equipment is typically required. In this way, the characterization or inspection or calibration of the laser processing system can be simplified in terms of hardware requirements and / or accelerated in terms of time consumption, thereby reducing procurement and / or operating costs and shortening maintenance time. This also provides the advantage that the precise location of the laser radiation and the precise location of the aiming laser radiation can be optionally checked, and their superposition in the working plane can be checked, thereby improving the safety of the high-precision laser processing system.

[0041] Furthermore, this offers the advantage that only one photodetector or energy sensor is required for characterization. This is particularly advantageous in that it allows for the selection of lower technical requirements for characterization compared to existing technologies and avoids potential discrepancies between measurements from multiple energy sensors typically used, thereby reducing the risk of characterization distortion.

[0042] Furthermore, the implementation method offers the advantage that the fluence or target fluence calibrated by the laser system can be stored as a variable related to the radiation diameter. This allows for calibration not to be performed separately for individual parameters, i.e., the spread and energy of the laser radiation—that is, separate calibrations monitoring energy and spot size individually—but rather to calibrate or characterize these two values ​​in combination, taking their correlation into account. This correlation could, for example, be that the fluence required for a specific removal volume can be determined based on a nonlinear function of the laser radiation spot size in the working plane.

[0043] The implementation also provides the advantage that the flux of the laser radiation in the working plane can be directly determined, and correspondingly, the flux can be monitored within predetermined tolerance boundaries within the characterized scope. In conventional, prior art methods, multiple power or energy parameters and magnitudes of the laser radiation are determined independently of each other, and their corresponding tolerance boundaries are checked; however, the flux in the working plane cannot be determined. This results in the corresponding tolerance boundaries for each parameter having to be chosen very narrowly in the prior art. According to some implementations, the flux can be determined, and possible predetermined tolerance boundaries can be checked, so that a combination of individual deviations in energy and in radiation diameter does not have to be incorrectly evaluated as erroneous, although the combination keeps the flux within tolerance.

[0044] Some implementations offer the advantage of optionally automating the characterization of laser radiation. For this purpose, it is particularly advantageous that the laser processing system is designed to independently or automatically arrange the aperture device in the working plane, and then independently or automatically remove it from the working plane again after the laser radiation characterization is performed.

[0045] The implementation provides the advantage of enabling laser radiation to be characterized using only a single calibration device, although multiple calibration devices can be used according to some implementations. Since a single calibration device is sufficient, deviations and distortions in the laser radiation characterization caused by differences between individual calibration devices can be avoided.

[0046] Furthermore, some implementations offer the advantage of allowing normal calibration to be performed initially in the working plane, and then, particularly during treatment or therapy, if the calibration device cannot be positioned in the working plane, the laser radiation can be temporarily characterized or monitored based on control and energy parameters by deflecting the laser radiation into the control plane. Although characterization in the control plane may not allow for true calibration, as calibration in the working plane is mandatory, for example, characterization in the control plane still provides valuable additional information about whether one or more parameters of the laser radiation have changed since the last calibration or characterization, and / or whether recalibration appears advantageous or necessary. In this way, the intervals between calibrations and / or characterizations in the working plane can be optionally extended, and / or a more regular characterization of the laser radiation can be achieved, especially during periods when the patient is already or still in the working plane.

[0047] Furthermore, some implementations offer the advantage that characterization can be performed particularly reliably because the calibration devices in the working plane and the control plane are optionally the last elements in the radiation path to the working plane or the control plane, and thus no additional optical elements are arranged in the radiation path when the laser radiation is applied to the object being treated or the eye to be treated, which are not taken into account when characterizing the laser radiation.

[0048] Some implementations offer the advantage of objectively characterizing laser radiation based on variations in the thickness of the test object, thereby achieving an objective characterization or evaluation of the laser radiation. This enables characterization to be performed more reliably than conventional characterization using volumetric paper, and allows for particularly precise adjustments to the laser or laser radiation that are optionally unaffected by or distorted by subjective impressions.

[0049] Furthermore, some implementations offer the advantage that laser radiation characterization can be performed automatically and independently by the laser or associated equipment. In particular, the provision, application, and / or evaluation (thickness determination) of the test object can be automated, thereby reducing the operator's workload. Particularly advantageously, multiple thickness variations can be determined for multiple applications at a single test site through material removal, enabling a high degree of safety or reliability in laser radiation characterization through averaging and / or statistics. According to an alternative implementation, the thickness variation is determined after each individual laser pulse in the pulse sequence.

[0050] Some implementations also offer the advantage that, from an economic point of view, characterization can be efficiently automated because the methods according to some implementations can be performed more cost-effectively than known prior art methods based on lens profile manufacturing and subsequent lens profile inspection.

[0051] Furthermore, some implementations offer the advantage that the characterization method can be integrated into laser devices (e.g., excimer lasers) and / or devices for corneal refractive correction by enabling the implementation of devices for characterizing laser radiation during planning and manufacturing. Alternatively, this provides the feasibility of retrofitting and / or extending existing excimer lasers and / or devices for corneal refractive correction with devices according to alternative implementations, wherein the existing excimer lasers and / or devices for corneal refractive correction do not have such devices for characterizing laser radiation.

[0052] Optionally, the aperture device further includes a third aperture opening with a plurality of aperture openings, the third aperture opening having a predetermined extension along the scanning direction and arranged at a predetermined distance from the first aperture opening along the scanning direction, wherein the predetermined extension is smaller than the average diameter of the laser radiation in the working plane. Optionally, the method further includes determining adjustment parameters of the laser processing system using the predetermined distance between the third aperture opening and the first aperture opening. This provides the advantage that scanning movement and / or, in particular, the deviation device used to perform scanning movement, can also be characterized and / or checked and / or calibrated. In particular, this is achieved by moving the laser radiation along the scanning direction such that it sweeps across the first and third aperture openings, wherein the laser radiation optionally moves directly and linearly from the first aperture opening to the third aperture opening. However, according to other embodiments, the laser radiation can move in a skipping manner, such that the laser radiation, for example, first sweeps across the first aperture opening, then jumps to and sweeps across the third aperture opening, and then jumps back to and sweeps across the second aperture opening. Then, it is possible to check, through the predetermined spacing between the first and third aperture openings, whether the scanning movement proceeds as preset, or whether there is a deviation between the rated and actual movement. For example, the presence of a deviation may be an indication of insufficient calibration and / or scanner magnification.

[0053] Optionally, the spread of laser radiation along the scanning direction is also determined based on the calculated energy transmitted through the multiple third aperture openings. Particularly optionally, determining the spread of laser radiation along the scanning direction includes averaging the spreads of the laser radiation calculated based on the first and third aperture openings. This provides the advantage of reducing measurement errors when necessary based on multiple measurements, thereby enabling a more reliable determination of the spread.

[0054] Optionally, laser radiation scanning is performed in both the first and second scanning sections, wherein the scanning direction in the first scanning section extends along a first dimension parallel to the working plane, and the scanning direction in the second scanning section extends along a second dimension parallel to the working plane. This provides the advantage that the spread of laser radiation along multiple scanning directions can be determined. Particularly optionally, the scanning directions extend in both scanning sections such that the spread of laser radiation in both dimensions of the working plane can be determined. Particularly optionally, the scanning direction in the first scanning section is perpendicular to the scanning direction in the second scanning section.

[0055] Optionally, the first aperture opening has a predetermined extension along the scanning direction in the first scanning segment. Furthermore, the aperture device may optionally have additional aperture openings with multiple aperture openings, the additional aperture openings having a predetermined extension along the scanning direction in the second scanning segment, the extension being smaller than the average diameter of the laser radiation in the working plane. In other words, for each scanning segment or for each of the two scanning directions, the aperture device has two aperture openings at a predetermined interval and with a predetermined extension (along the scanning direction), so that the two aperture openings are available for determining the extension in the two scanning directions or along the two scanning segments. In this way, the calibration and / or characterization of the scan movement can also be performed in two dimensions.

[0056] Optionally, the aperture opening having a predetermined extension along the scanning direction that is smaller than the average diameter of the laser radiation in the working plane has an extension no greater than 90%, more preferably no greater than 80%, even more preferably no greater than 70%, more preferably no greater than 60%, and most preferably no greater than 50% of the average diameter of the laser radiation in the working plane. Alternatively or additionally, the extension along the scanning direction corresponds to at least 1%, further preferably at least 5%, even more preferably at least 10%, more preferably at least 15%, and most preferably 20% of the average diameter of the laser radiation in the working plane. For example, the laser radiation in the working plane can have an average diameter (FWHM) of approximately 0.6 mm to 0.8 mm, wherein larger or smaller diameters can also be used. The extension of the aperture element can, for example, be between 0.1 mm and 0.4 mm along the scanning direction, and the aperture element has a predetermined extension along the scanning direction that is smaller than the average diameter of the laser radiation. The predetermined extensions of a plurality of aperture openings having a predetermined extension smaller than the average diameter of the laser radiation can independently have the same extension or size or have different extensions from each other.

[0057] Optionally, the plurality of aperture openings includes at least two aperture openings for each scanning segment. These at least two aperture openings have a predetermined extension along the respective scanning direction that is smaller than the average diameter of the laser radiation in the working plane, and are arranged relative to each other at a predetermined spacing along the respective scanning direction. This provides the advantage that the extension or diameter of the laser radiation along each scanning segment can be determined, and that the movement of the scanner movement or deviation device movement, i.e., the movement of the deflector used to move the laser radiation in the working plane, can be checked and / or calibrated according to the predetermined spacing of the aperture openings by, for example, sequentially scanning the two aperture openings with a coherent linear movement, and determining the required deflection and / or movement of the deflector for this purpose. In other words, it is optionally possible to determine in this way whether the actual induced scanning movement corresponds to the expected aiming scanning movement. If not, adjustment and / or calibration of the deflector may be advantageous or even necessary.

[0058] Optionally, this method involves checking the laser radiation, i.e., the working laser radiation of the laser processing system and optionally, the aiming laser radiation. The laser radiation is optionally the laser radiation used to perform laser processing on the object being processed in the working plane. Here, the laser radiation can have a center wavelength that is invisible to the human eye or only difficult to see, i.e., a center wavelength in the ultraviolet or infrared spectral range, which makes adjusting the laser radiation difficult. Therefore, it is advantageous to use aiming laser radiation to adjust the laser processing system, the aiming laser radiation optionally having a center wavelength in the visible spectral range. Optionally, the propagation directions of the laser radiation and the aiming laser radiation are coupled to each other such that they propagate along the same optical axis, and in this way, adjusting the laser processing system using the aiming laser radiation also causes adjustment of the laser radiation. This provides the advantage that the coupling between the laser radiation and the aiming laser radiation can be checked to ensure the reliability of adjusting the laser processing system using the aiming laser.

[0059] Optionally, the aperture device further includes one or more aiming laser detectors to detect the aiming laser radiation transmitted through the aperture opening and / or determine its energy and / or power. Here, the one or more aiming laser detectors can optionally be constructed separately from the photodetector used to detect the laser radiation. For example, the aiming laser detector can be constructed differently from the photodetector. For example, the aiming laser detector can optionally be constructed differently from the photodetector in terms of its sensor area and / or its spectral sensitivity. Particularly optionally, the photodetector is designed to detect laser radiation and is correspondingly coordinated to the wavelength in terms of spectral sensitivity and to the energy of the laser radiation in terms of the damage threshold, while the one or more aiming laser detectors can optionally be coordinated to the aiming laser radiation in terms of both spectral sensitivity and damage threshold.

[0060] Optionally, the method further includes determining the flux and / or intensity of the laser radiation in the working plane using the calculated spread and energy parameters of the laser radiation. For this purpose, it is advantageous, for example, to determine the spread of the laser radiation in two dimensions of the working plane. Determining the flux and / or intensity provides the advantage of directly determining parameters relevant to the removal of material to be induced, particularly for ophthalmic surgery, i.e., the removal of a portion of the cornea, and enabling particularly precise prediction of the desired removal of the object to be treated (e.g., the eye).

[0061] Optionally, the method includes adjusting the laser parameters and repeating steps b) through d) after adjusting the laser parameters. In other words, after an optional adjustment of the laser parameters or laser radiation, a check of the laser radiation is performed again. This provides the advantage that the results of the adjustments can be checked and it can be determined whether the adjustments made achieved the desired results and / or whether further adjustments to the laser radiation or laser processing system are desirable and / or advantageous and / or necessary.

[0062] Optionally, the aperture device is designed to absorb and / or reflect portions of laser radiation that are not transmitted through the aperture opening. Optionally, the aperture device is designed such that laser radiation is transmitted only through the aperture opening. Except for the aperture opening, the aperture device is optionally opaque to laser radiation. Here, the aperture device is optionally constructed such that applying laser radiation to the aperture device will not cause damage and / or destruction to the aperture device, which would impair its function. For example, the aperture device can be made at least partially of plastic and / or metal. For example, the aperture device can include optional black anodized metal to reduce the reflectivity of the aperture device, so as to, for example, avoid damage and / or injury and / or danger to people through laser radiation reflected by the aperture device. Alternatively, the surface of the aperture or aperture device can be constructed diffusingly, scattering incident light from the UV and / or visible and / or infrared (IR) spectral ranges into a large spatial angle. This provides the advantage that at least one aperture opening, particularly the central aperture, can be identified as the pupil in the eye tracker's IR image.

[0063] Optionally, the first aperture opening is slit-shaped, and the predetermined extension corresponds to a predetermined width of the slit. This provides the advantage that the aperture opening can have a very small and defined width along one dimension, and can be constructed along another dimension larger than the average diameter of the laser radiation. Thus, the transmission portion of the laser radiation is limited only along one dimension, for example, where a "strip" of the laser radiation is transmitted, such that although the width along the scanning direction is limited, the laser radiation is transmitted in the largest possible proportion along another dimension perpendicular to the scanning direction to obtain the best possible signal-to-noise ratio. Optionally, the aperture device has a plurality of slit-shaped aperture openings, each aperture opening having a predetermined width corresponding to a predetermined extension, and the aperture openings are arranged in pairs at a predetermined distance from each other.

[0064] Optionally, the second aperture is constructed as a circular aperture with an extension substantially corresponding to the extension of the laser radiation. The fact that the extension of the aperture opening substantially corresponds to the extension of the laser radiation means that, particularly when the laser radiation and the aperture opening are arranged concentrically, the laser radiation can be transmitted substantially completely through the aperture opening. This means that the power or energy not transmitted or blocked by the second aperture opening is less than 0.5% of the total power or energy. Here, the circular design of the aperture opening, for example, as a circular aperture, is particularly advantageous for matching the laser radiation, because the circular aperture optionally also has a circular cross-sectional shape in the working plane.

[0065] Alternatively, the aperture and photodetector are constructed parallel to each other, one above the other. This provides the advantage that the aperture can be constructed in a particularly compact manner, and correspondingly, it is particularly well-suited for arranging the aperture in the working plane. Here, optionally, arranging the aperture in the working plane means that the aperture and, in particular, the aperture opening are arranged in the working plane.

[0066] Optionally, the laser processing system is configured to: scan the laser radiation above the aperture device along a scanning direction parallel to the working plane using a deflection device, such that the laser radiation at least partially sweeps across the aperture opening. Furthermore, the laser processing system is configured to: determine the energy of the laser radiation transmitted through the aperture openings respectively during the scanning process using a photodetector. Additionally, the laser processing system is further configured to: determine the spread of the laser radiation along the scanning direction based on the energy transmitted through the first aperture opening, and determine the energy parameters of the laser radiation based on the energy transmitted through the second aperture opening.

[0067] Practically, the laser processing system is constructed as a laser treatment system for performing ophthalmic or refractive surgeries on the eye, particularly for refractive corneal surgeries.

[0068] Furthermore, according to an alternative embodiment, the aperture device according to one embodiment can be used to characterize the laser radiation of the laser processing device in both the working plane and the control plane (e.g., within the laser processing system). The method for characterization can also be performed such that calibration parameters in the working plane and control parameters in the control plane are determined.

[0069] Optionally, the method for characterizing the laser radiation of a laser processing system is implemented such that the method includes the following steps:

[0070] - Determine the energy parameters of the laser radiation;

[0071] - Provide a calibration device in the working plane of the laser processing system, and apply laser radiation to the calibration device under the same conditions as when processing the object using laser radiation;

[0072] - The calibration parameters are determined in the working plane using a calibration device;

[0073] - Provide a calibration device in a control plane outside the working plane and deflect the laser radiation so that laser radiation is applied to the calibration device in the control plane;

[0074] - The control parameters are determined in the control plane using a calibration device;

[0075] - Determine the deviation coefficient that characterizes the deviation between the calibration parameters and the control parameters;

[0076] - The laser radiation is characterized using the deviation coefficient and energy parameters with the aid of a calibration device in the control plane.

[0077] Here, the calibration device can include or be configured as an aperture device. Furthermore, the calibration parameters and / or control parameters can be determined using methods for characterizing the laser radiation of the laser processing system.

[0078] According to an alternative embodiment, the laser processing system can also be configured to characterize laser radiation in a working plane and a control plane. For this purpose, the laser processing system may optionally include an energy sensor designed to determine energy parameters of the laser radiation. Here, the laser processing system also includes: a calibration device selectively arranged in the working plane of the laser processing system and capable of applying laser radiation, and also arranged in a control plane outside the working plane and capable of applying laser radiation; and a deflection element arranged in the radiation path of the laser radiation such that the deflection element deflects the laser radiation oriented on the working plane into the control plane. Here, the laser processing system is designed to: arrange the calibration device in the working plane and determine calibration parameters, arrange the calibration device in the control plane and determine control parameters, determine a deviation coefficient characterizing the deviation between the calibration parameters and the control parameters, and characterize the laser radiation in the control plane using the energy parameters and the deviation coefficient by means of the calibration device.

[0079] Optionally, the calibration device provided in the control plane is a separately constructed calibration device from the calibration device provided in the working plane. In other words, according to an optional embodiment, two separate calibration devices are used or provided in the control plane and the working plane. This provides the advantage that the calibration device arranged in the control plane can be optionally held in position, while only the calibration device provided in the working plane must be removed from the working plane for eye treatment or handling of the object. The calibration devices can optionally be constructed in the same or even identical manner.

[0080] According to another alternative implementation, the same calibration device is used in both the working plane and the control plane. This provides the advantage that only one calibration device needs to be provided. Furthermore, this provides the advantage that deviations between calibration parameters and control parameters due to discrepancies between two separate calibration devices can be avoided.

[0081] Optionally, the control parameters are determined immediately after the calibration parameters are determined. This provides the advantage that deviations caused by temporal fluctuations in the laser processing system can be minimized.

[0082] Optionally, the energy parameters are determined at least during the determination of the calibration parameters and during the determination of the control parameters. More specifically, the determination of the energy parameters can be ongoing. This provides the advantage that variations derived from deviations in the laser radiation energy can be identified and taken into account when comparing the calibration parameters with the control parameters.

[0083] Optionally, the deflection of the laser radiation is achieved using only a single optical deflection element. In other words, the change in the radiation path of the laser radiation deflected from the working plane to the control plane is achieved solely by means of the deflection element. This provides the advantage that interference with the laser radiation is minimized, where interference can cause a deviation between the laser radiation provided in the working plane and the laser radiation provided in the control plane. Particularly optionally, the deflection element can be monitored and / or periodically checked, for example, by determining the reflectivity and / or transmittance of the deflection element. For example, laser radiation and / or other optical radiation can be used for this purpose.

[0084] Optionally, the laser processing system is designed to automatically switch the arrangement of the calibration device between the working plane and the control plane and / or automatically introduce deflection elements into and / or remove them from the laser radiation. This provides the advantage that only one calibration device is required, and optionally, the calibration and / or characterization of the laser radiation can be performed fully automatically.

[0085] Optionally, the calibration device is designed to provide measurements that are linearly scaled with the laser energy. For example, the calibration device can have an aperture assembly with an aperture and a photodetector, by means of which the flux and / or intensity of the laser radiation can be determined by scanning the laser radiation across one or more apertures. Here, it is advantageous that the measurement signal from the photodetector is linearly related to the energy and / or flux of the laser radiation.

[0086] Alternatively, the laser radiation is deflected into the control plane by means of a deflection element, which is introduced into the radiation path for this purpose. For example, the deflection element can be constructed as a mirror. According to another embodiment, the deflection element can also remain in the radiation path, and the laser radiation can be deflected into the control plane by means of a change in the orientation of the deflection mirror.

[0087] Optionally, the laser processing system is designed to independently move the calibration device or aperture device between the working plane and the control plane, for example by means of corresponding translation and / or pivoting devices. For example, the positional change is achieved such that the optical path lengths of the laser radiation to the working plane and the control plane are the same.

[0088] Optionally, the method includes a functional check of the photodetector to verify its functionality. For example, such a functional check can be performed based on secondary effects of the interaction between laser radiation and the detector, such as by utilizing the resulting fluorescence and / or temperature and / or mechanical shock waves and / or acoustic waves.

[0089] According to an optional embodiment, the aperture device has two first aperture openings, which are slit-shaped and extend parallel to each other. The width of the slit-shaped first aperture opening is smaller than the spread of the laser radiation in the working plane, such that the energy of the laser radiation transmitted through the respective aperture opening can be determined by scanning the laser radiation through the first aperture opening, and the spread of the laser radiation in the working plane can be determined therefrom. The two slit-shaped first aperture openings are arranged at a predetermined distance from each other, optionally at a predetermined distance from each other in a direction perpendicular to the longitudinal direction of the intermittent aperture openings. Furthermore, here, the deviation device or scanner of the laser processing system can be calibrated by sequentially scanning the two first aperture openings perpendicular to the longitudinal direction of the slits during movement. In addition, the aperture device according to the optional embodiment has another aperture opening, which is, for example, constructed as a circular aperture and has a shape and size such that when the laser radiation passes through the second aperture opening, the laser radiation is transmitted substantially completely through the second aperture opening, so that the energy or power of the laser radiation can be determined by means of the second aperture opening. Here, the photodetector is arranged such that a portion of the laser radiation transmitted through the corresponding aperture opening is incident on the photodetector and can be determined by the photodetector. The second aperture opening is optionally arranged between the two first aperture openings. Thus, the laser radiation can be guided in a single linear scanning movement, such that the laser radiation first sweeps across the slit-shaped first aperture opening, then the (circular aperture-shaped) second aperture opening, and subsequently across the slit-shaped second aperture opening. This allows the laser radiation spread (at the slit-shaped first aperture opening), the laser radiation energy (at the circular aperture-shaped second aperture opening), and the scanner calibration (based on movement over the two slit-shaped aperture openings) to be determined by a single scanning movement. The magnitude or target flux of the laser radiation in the working plane can be determined by the determined magnitude and energy of the laser radiation. Therefore, this embodiment provides the feasibility of performing flux determination and scanner calibration in a single process.

[0090] According to another optional embodiment, the aperture opening has: a slit-shaped aperture opening, the width of which is less than the spread of the laser radiation in the working plane; and a circular aperture opening, the circular aperture opening being larger than the spread of the laser radiation in the working plane, so as to determine the flux of the laser radiation in the working plane. Here, the aperture opening is arranged superimposed with a photodetector to determine the energy and flux of the laser radiation. Furthermore, the aperture device according to the embodiment has another slit-shaped aperture opening superimposed with a targeting laser detector, and by means of this other slit-shaped aperture opening, the measurement between the targeting laser radiation and the laser radiation can be realized. This embodiment provides the advantage that the determination of the laser radiation flux and the measurement between the laser radiation and the targeting laser radiation can be realized in one process in the working plane.

[0091] According to an optional implementation, the method further includes determining a target fluence. Here, the target fluence is a desired value for the fluence that should be used for processing by means of a laser processing system. The target fluence can be related to the focal size or spot size of the laser radiation in the working plane. For example, the method can therefore include determining the (actual) fluence, i.e., the actual value of the fluence, and determining the focal size or spread of the laser radiation in the working plane. If the fluence is outside the tolerance range, then, for example, readjustment or calibration of the laser processing system can be performed or recommended, such readjustment or calibration including, for example, changing the power and / or energy of the laser radiation to achieve the desired target fluence.

[0092] The target fluence can be optionally determined, for example, by first determining the radiation diameter *d* of the laser radiation in the working plane. Then, the target fluence is calculated from this diameter (from other known correlations). Furthermore, the energy of the laser radiation is measured. The current fluence of the laser radiation in the working plane is determined from the energy and the diameter *d*. The current fluence is compared to the target fluence. In the presence of deviations, for example, the laser parameters (typically the energy of the laser radiation) are adjusted so that the actual fluence and the target fluence are sufficiently well aligned, i.e., until below a predetermined tolerance boundary. In this process, the target fluence can therefore optionally be itself a variable, which is related to the parametric radiation diameter or extension of the laser radiation in the working plane.

[0093] Therefore, the target fluence can provide a wealth of information because calculating the target fluence from the radiation diameter optionally takes into account removal calibration (i.e., indicating "how much PMMA or corneal volume is removed at what radiation size and energy"). This information is optionally collected and predetermined independently of the methods described herein, making it possible to ensure accurate removal by means of fluence calibration.

[0094] For radiation diameters of 700 μm or 600 μm, example values ​​for the target fluence (FZiel) could be, for example:

[0095] FZiel (700μm) = 190mJ / cm 2

[0096] FZiel (600μm) = 240mJ / cm 2

[0097] The target fluence typically exhibits a nonlinear variation with the radiation diameter.

[0098] The optional determination of the target flux provides a certain flexibility with a diameter that has (slow) fluctuations (e.g., in the case of drift in the imaging system), so that the removal can be well calibrated because the radiation diameter and laser energy are fully taken into account.

[0099] The steps for optionally determining the target injection volume according to an alternative implementation method are described below by way of example:

[0100] 1) Determine the spread of the laser radiation (spot size d) and the energy E of the laser radiation in the working plane;

[0101] 2) Calculate the actual injection volume (actual injection volume) based on the spread (d) and energy E of the laser radiation.

[0102] 3) Calculate the target flux from the spread (d) of the laser radiation and the predetermined transformation;

[0103] 4) Compare the actual betting volume with the target betting volume and determine the feasible deviation;

[0104] 5) Check the necessity of laser processing system calibration based on feasible deviations, and perform calibration if necessary.

[0105] The alternative design schemes explained below relate in particular to alternative implementations that include applying laser radiation to the test object and determining the change in thickness of the test object at the test site caused by the applied laser radiation. This design scheme can optionally be combined with other methods for characterizing laser radiation.

[0106] According to one alternative embodiment, determining the change in thickness of the test object at the test site includes: measuring the thickness of the test object at the test site after laser irradiation is applied, and comparing the determined thickness with the thickness of the test object at the test site before laser irradiation is applied. The thickness of the test object at the test site can be known in advance and stored in the system, enabling a comparison between the thickness determined after application and the previously known thickness before application. This comparison can optionally be implemented by mathematically subtracting and / or comparing the determined thicknesses. Thus, the comparison can optionally be used to allow subsequent laser material processing, such as at the cornea of ​​the human eye, and / or to configure laser material processing or removal, for example, with regard to optimal processing parameters, such as laser pulse energy and / or number of laser pulses, laser spot size, and / or scanning pattern.

[0107] However, in order to achieve the desired accuracy of the thickness or thickness variation determination, for example, between 100 nm and 1 μm, depending on the alternative implementation, it is necessary that the thickness of the test object be known before applying laser radiation with the correspondingly high accuracy.

[0108] According to an optional embodiment, determining the thickness change of the test object at the test site further includes measuring the thickness of the test object at the test site before the application of laser radiation. According to this optional embodiment, in addition to determining the thickness of the test object after the application of laser radiation, it is possible to determine the thickness of the test object before the application of laser radiation. This provides the advantage that the thickness change caused by the application of laser radiation can be determined with particular reliability. Furthermore, this allows the use of test objects with unknown thicknesses and / or thicknesses whose specifications are not within the desired accuracy range, and / or the use of test objects with surface roughness significantly relative to the desired accuracy, thereby reducing the cost of providing the test objects and enabling laser radiation characterization in a particularly inexpensive manner.

[0109] According to an optional embodiment, the method further includes configuring the laser radiation for ongoing and / or subsequent material processing based on the determined thickness change of the test object at the test site caused by the applied laser radiation. In other words, optionally, the configuration and / or adjustment of the parameters of the laser radiation and / or other parameters of material removal by means of laser radiation are based on the laser radiation characterization performed. Particularly optionally, the laser radiation is characterized periodically, and possible adjustments are made to the parameters of the laser radiation and / or material removal method based on the characterization. If necessary, the characterization of the laser radiation can also require or advantageously cause interruption and / or termination of material removal by means of laser radiation. Alternatively or additionally, the laser radiation can be automatically adjusted and / or prompts can be output to the user indicating that adjusting the laser radiation and / or the equipment used for material removal would be advantageous or necessary.

[0110] According to one alternative implementation, the thickness variation of the test object at the test site is determined by means of optical thickness measurement. This offers the advantage that the determination can be performed particularly quickly and / or with high sensitivity. Furthermore, it is advantageous for the reliable automation of the determination of thickness and the evaluation of the determined thickness.

[0111] According to an optional embodiment, the optical measurement includes incident optical radiation onto the test object from a side of the test object opposite to the incident direction of the laser radiation. Furthermore, the optical measurement optionally includes detecting the reflection and / or scattering of the optical radiation at and / or within the test area of ​​the test object. In other words, the application of laser radiation to the test object can be performed on a first side of the test object, while the incident optical radiation used to determine the thickness of the test object is performed on an opposite side of the test object. Then, based on the reflection and / or scattering of the optical radiation incident at the surface of the test object that has been / is undergoing laser radiation application, the thickness of the test object at the test area can be determined or measured. This provides the advantage that optical measurements can be performed using a particularly simple and / or compact measurement structure.

[0112] According to one alternative implementation, the optical measurement includes measuring the thickness of the test object at the test site using at least one confocal colorimetric sensor. This allows for particularly accurate and rapid measurement of the test object's thickness. Furthermore, the use of one or more confocal colorimetric sensors reliably automates the characterization of the optical measurements and the evaluation of the measurement results to characterize laser radiation. For example, a confocal colorimetric sensor, such as those supplied by the manufacturer MIKROEPSILON, can be used for this purpose. The advantage of such a confocal colorimetric sensor is that it can be matched to the corresponding needs with a wide variety of sizes in terms of the measurement area and the achievable measurement accuracy, or can be selected accordingly. In particular, confocal colorimetric sensors with measurement accuracy up to 10 nm are available, enabling the sensor to achieve the accuracy required for corneal refractive correction when characterizing laser radiation.

[0113] According to one alternative embodiment, the laser radiation is provided as pulsed laser radiation, wherein the laser radiation is optionally applied to the test object such that a single laser pulse sequence, a series of laser pulses, or a series or multiple laser pulses having a specific number of laser pulses removes a portion of the material of the test object at the test site. Optionally, other laser pulse sequences are applied to the test object at other test sites. This provides the advantage that the characterization of the laser radiation can be achieved with particular precision because the amount of energy applied can be specified with particular accuracy according to the number of laser pulses.

[0114] In one alternative implementation, a sequence of laser pulses with different energies is applied to each test site. This allows for particularly precise characterization based on comparisons of the thickness of different test sites.

[0115] According to one alternative embodiment, the test object is at least partially made of PMMA. Optionally, the dimensions of the test object are determined such that one or more test sites can be arranged on it. For example, the test object can be much larger than a single test site. For example, the test object can be displaced relative to the laser radiation in a direction and / or plane perpendicular to the laser radiation propagation direction, and / or the laser radiation can be moved relative to the test object to apply laser radiation to other parts of the test object. According to one alternative embodiment, for example, the test object can be rotated perpendicular to the laser radiation propagation direction or optical axis to provide a separate test site for each pulse and / or each predetermined laser pulse series or pulse sequence. This provides the advantage of being able to use the test object multiple times and correspondingly reducing the necessity and / or frequency of switching test objects. Therefore, this provides the advantage of reducing maintenance work. It is advantageous, particularly for the optional reuse of test subjects between multiple corneal treatments, that the laser radiation is temporarily diverted from the treatment area of ​​the cornea and deflected onto the test subject in other locations, for example, by means of a folding lens, and that the test subject is folded into the usual corneal treatment area between treatments and / or optionally moved into the corneal treatment area in a motor-driven manner. The deviation between the laser focal position on the cornea and on the surface of the test subject should optionally be designed to be small in order to maintain similar treatment conditions, for example, such that the laser spot sizes may optionally deviate from each other by a factor of less than 2.

[0116] According to one alternative embodiment of the optional implementation, the device can be configured such that at least a portion of the test object can be scanned by means of a relative movement between the test object and at least one confocal colorimetric sensor, at least partially perpendicular to the optical axis of the test object, and the thickness at at least one test site can be determined therein. The relative movement can be achieved, for example, by movement of at least one confocal colorimetric sensor and / or the test object. By inducing relative motion and scanning at least a portion of the test object, the inspectable area can be significantly expanded. It can also be optionally achieved that the thickness in different removal zones or test sites is determined using the same confocal colorimetric sensor, wherein different bombardment numbers or laser pulse numbers and / or different radiation energies are applied to different test sites or removal zones. This facilitates determining the material removal per laser pulse or bombardment.

[0117] According to another alternative implementation, the optical axis of the confocal colorimeter is superimposed on the optical axis of the laser radiation, for example, by means of a beam splitter. This allows for the determination of material removal by each individual bombardment or laser pulse, even when processing the cornea of ​​a human eye. In this embodiment, it is advantageous to position the confocal colorimeter on the side of the test object or cornea where the laser radiation is incident.

[0118] According to an optional implementation, a device for characterizing laser radiation can be integrated into a laser system. Here, the device can optionally include means for automatically providing test objects. For example, multiple test objects can be stored in the device and / or in the laser system, and then used to characterize laser radiation when needed. Furthermore, the device and / or laser system can, for example, have a maintenance well from which used test objects can be removed and / or unused test objects can be reloaded. For example, one or more test objects can also be constructed in the form of a diaphragm strip and / or in the form of an adjustable and / or rotatable plastic disc, which provides multiple surfaces suitable for the test site by shifting and / or rotating or turning the optical axis perpendicular to the laser radiation. For example, the plastic disc can be constructed according to a CD type. This can reduce maintenance costs for replacing test objects. Optionally, in this way, thousands of processes for characterizing laser radiation can be performed before one or more test objects must be replaced.

[0119] According to an optional embodiment, the method for characterizing the laser radiation of a laser processing system may further include determining energy parameters of the laser radiation. Furthermore, the method may include: providing a calibration device in the working plane of the laser processing system, applying laser radiation to the calibration device under the same conditions as processing an object using laser radiation, and determining calibration parameters in the working plane using the calibration device. Furthermore, the method may include: providing a calibration device in a control plane outside the working plane and deflecting the laser radiation such that laser radiation is applied to the calibration device in the control plane, and determining control parameters in the control plane using the calibration device. Furthermore, the method according to an optional embodiment includes: determining a deviation coefficient characterizing the deviation between the calibration parameters and the control parameters, and characterizing the laser radiation using the energy parameters and the deviation coefficient using the calibration device in the control plane.

[0120] Furthermore, according to an optional embodiment, the device for corneal refractive correction includes a laser processing system for treating a subject by means of laser radiation processing, or a laser processing system configured as such. Here, the laser processing system includes an energy sensor designed to determine energy parameters of the laser radiation. Additionally, the laser processing system includes a calibration device selectively arranged in the working plane of the laser processing system and capable of applying laser radiation, and also capable of being arranged in a control plane outside the working plane and capable of applying laser radiation; and a deflection element arranged in the radiation path of the laser radiation such that the deflection element deflects the laser radiation oriented in the working plane to the control plane. Here, the laser processing system is designed to: arrange the calibration device in the working plane and determine calibration parameters; arrange the calibration device in the control plane and determine control parameters; determine a deviation coefficient characterizing the deviation between the calibration parameters and the control parameters; and characterize the laser radiation using the deviation coefficient and energy parameters by means of a control device in the control plane.

[0121] Here, the calibration apparatus may optionally be configured as, or include, a device for characterizing laser radiation according to a feasible embodiment. Specifically, the calibration apparatus includes a test object holder and a measuring device, wherein a test object is provided in the test object holder for characterizing the laser radiation.

[0122] According to an alternative embodiment, the method for characterizing laser radiation of a laser processing device or a device for refractive corneal correction can therefore be performed optionally in the working plane and also in the control plane, optionally inside the laser processing system.

[0123] According to an alternative embodiment, the calibration device arranged in the control plane is a separately constructed calibration device from the calibration device passing through the working plane. In other words, according to an alternative embodiment, two separate calibration devices are used or provided, one in the control plane and one in the working plane. This provides the advantage that the calibration device optionally arranged in the control plane can remain in place, and the calibration device passing only through the working plane must be removed from the working plane for eye treatment or handling of the object. The calibration devices can optionally be constructed of the same type or even identically.

[0124] According to another alternative implementation, the same calibration device is used in both the working plane and the control plane. This provides the advantage that only one calibration device needs to be provided. Furthermore, this provides the advantage that deviations between calibration parameters and control parameters caused by discrepancies between two separate calibration devices can be avoided.

[0125] Optionally, the control parameters are determined immediately after the calibration parameters are determined. This provides the advantage of minimizing deviations caused by time fluctuations in the laser processing system.

[0126] Optionally, the energy parameters are determined at least during the determination of calibration parameters and during the determination of control parameters. Particularly optionally, the energy parameters are determined continuously. This provides the advantage of being able to identify variations derived from deviations in the laser radiation energy and to take these variations into account when comparing calibration and control parameters.

[0127] Optionally, the deflection of the laser radiation is achieved using only a single optical deflection element. In other words, the change in the radiation path of the laser radiation from the working plane to the control plane is achieved solely by means of the deflection element. This provides the advantage that interference with the laser radiation, which could cause a deviation between the laser radiation provided in the working plane and the laser radiation provided in the control plane, is minimized. Particularly optionally, the deflection element can be monitored and / or periodically checked, for example, by determining its reflectivity and / or transmittance. For example, laser radiation and / or other optical radiation can be used for this purpose.

[0128] Optionally, the laser processing system is designed to: automatically switch the arrangement of the calibration device between the working plane and the control plane, and / or automatically introduce deflection elements into and / or remove them from the laser radiation. This provides the advantage that only one calibration device is required, and optionally, the calibration and / or characterization of the laser radiation can be performed fully automatically.

[0129] Optionally, the calibration device is designed to provide measurements that scale linearly with the laser energy. For example, the calibration device can be designed to determine the change in thickness and / or material removal of the test object caused by the application of laser radiation, wherein the material removal and / or change in thickness can optionally scale linearly with the laser radiation energy. Alternatively, the calibration device can have an aperture device with an aperture and a photodetector, by means of which the flux and / or intensity of the laser radiation can be determined by scanning the laser radiation on one or more apertures. Advantageously, the measurement signal from the photodetector is linearly related to the energy of the laser radiation.

[0130] Alternatively, the laser radiation is deflected into the control plane by means of a deflection element, which is introduced into the radiation path for this purpose. For example, the deflection element can be constructed as a mirror. According to another embodiment, the deflection element can also remain in the radiation path, and the laser radiation can be deflected into the control plane by means of a change in the orientation of the deflection mirror.

[0131] Optionally, the laser processing system is designed to move the calibration device independently between the working plane and the control plane, for example by means of corresponding translational and / or pivoting devices. For instance, the positional change is achieved such that the optical path lengths of the laser radiation to the working plane and the control plane are the same.

[0132] It goes without saying that the features and implementations explained above and below can be considered not only as disclosed in the separately explicitly proposed combinations, but also as other technically meaningful combinations and implementations. Attached Figure Description

[0133] Further details and advantages of the alternative implementations will now be explained in more detail with reference to the accompanying drawings, based on the following examples and alternative implementations.

[0134] The attached diagram shows:

[0135] Figures 1A to 1D A schematic diagram of an aperture device according to an optional embodiment is shown.

[0136] Figure 2A and 2B Two cross-sectional views of the aperture device according to an optional embodiment are shown.

[0137] Figure 3 illustrates an explanatory diagram of an alternative implementation for determining the spread of laser radiation.

[0138] Figure 4 A processing system according to an optional implementation is shown.

[0139] Figure 5 A schematic diagram of the aperture device according to the embodiment shown in Figure 2 is presented, along with further explanation.

[0140] Figure 6A and 6B The laser processing system 1000 is shown in two different operating modes for characterizing laser radiation 1002, according to an optional implementation.

[0141] Figure 7A and 7B A schematic diagram of the processing head 1020 of a laser processing system 1000 according to an optional embodiment is shown.

[0142] Figure 8A and 8B An apparatus for characterizing laser radiation is shown according to an optional embodiment.

[0143] Figure 9 A device for characterizing laser radiation during corneal refractive correction, according to an optional implementation, is shown.

[0144] Figures 10A to 10CDifferent alternative implementations of the test object are shown.

[0145] In the following figures, for simplicity, the same or similar elements in various embodiments are given the same reference numerals. Detailed Implementation

[0146] Figure 1A A top view of an aperture device 10 according to an alternative embodiment is shown schematically. In the top view, the aperture 12 of the aperture device 10 can be particularly identified, in which a plurality of aperture openings 14 are constructed. Specifically, slit-shaped aperture openings 14a belong to the aperture openings 14, and these slit-shaped aperture openings are constructed in pairs with a certain spacing 100a or 100b, and each has a predetermined width. According to the illustrated embodiment, the aperture openings 14a have the same thickness, and the spacings 100a and 100b are also designed to the same dimensions. However, this may differ according to other embodiments.

[0147] Furthermore, the aperture device 10 has another aperture opening 14b, which is constructed as a circular hole and is centrally arranged in the aperture 12 according to the illustrated embodiment. A slit-shaped aperture opening 14a is arranged around the central circular aperture opening 14b.

[0148] Photodetector 16 is positioned below aperture 12 (therefore in Figure 1A (Unidentifiable in the image), the detector surface 16 of the photodetector is superimposed on the aperture opening 14. According to the embodiment shown, the photodetector 16 has a circular detector surface, the circumferential boundary of which is indicated by dashed lines. The photodetector 16 is designed to detect laser radiation, i.e., the operating laser radiation, and determine the energy incident on the photodetector from the laser radiation. Therefore, the photodetector 16 is designed for the laser radiation wavelength. If laser radiation with wavelengths in the ultraviolet spectral range is used, the photodetector 16 may optionally also be designed for the corresponding wavelength of the ultraviolet spectral range or the operating radiation. The gridding, i.e., pixelation, of the photodetector 16 is not absolutely necessary, but it is certainly feasible. More precisely, it is sufficient that the laser radiation energy transmitted through one or more aperture openings 14 can be detected and determined by means of the photodetector.

[0149] Here, the photodetector 16 and the aperture opening 12 are arranged vertically to each other, such that all the aperture openings 14 are superimposed on the photodetector 16. When the corresponding aperture opening 14 is scanned by laser radiation, the energy transmitted through each aperture opening 14 is directed onto the photodetector 16 and can be detected by the photodetector.

[0150] Furthermore, the aperture device 10 according to the illustrated embodiment has two additional aperture openings 18 for targeting laser radiation. These aperture openings are also slit-shaped and arranged at a certain distance 100a from each other, wherein the slits have a predetermined extension or width. Because the targeting laser radiation typically has a different center wavelength than the working laser radiation, the photodetector 16 is not designed to detect the targeting laser radiation and / or determine its energy and / or power. Therefore, individual targeting laser detectors 20 are associated with the aperture openings 18, with the target laser detectors arranged below their respective aperture openings 18, as indicated by the dashed lines. One of the two aperture openings 18 extends vertically and has a predetermined width in the horizontal direction, while the other aperture opening 18 extends horizontally and has a predetermined width in the vertical direction. Thus, the extension of the target laser radiation in the working plane in two dimensions can be determined, referred to in the present case as the horizontal and vertical dimensions.

[0151] Thus, the aperture device can inspect and aim at laser radiation, even if they have completely different center wavelengths.

[0152] Here, the aperture device 10 is designed and constructed such that it can be arranged in the working plane of the laser processing system. In particular, it is therefore advantageous to select the size of the aperture device 10 so that it can be positioned even in potentially narrow spaces within the working plane.

[0153] Figure 1B An aperture device 10 according to another alternative embodiment is shown. The aperture device according to the alternative embodiment has two slit-shaped or slot-like aperture openings 14a, which are arranged parallel to each other at a predetermined spacing 100a. Here, the aperture openings 14a have a significantly smaller diameter or average width of the laser radiation in the working plane. Furthermore, the aperture device 10 has another aperture opening 14b, which is constructed as a circular aperture and larger than the laser radiation in the working plane, such that the laser radiation can be transmitted substantially entirely through the circular aperture opening 14b. Additionally, the aperture device 10 has a photodetector 16 disposed below the aperture 12, capable of detecting and probing the laser radiation passing through the aperture opening 12.

[0154] The aperture device 10 enables the determination of the laser radiation flux in the working plane and the calibration of the scanner in a single process. This can be achieved, for example, by scanning the laser radiation in a straight line starting from the left side via the aperture device, such that the laser radiation first sweeps across the left slit-shaped aperture opening 14a (perpendicular to the longitudinal axis of the aperture opening), then passes centrally through the circular aperture opening 14b, and further sweeps across the right slit-shaped aperture opening 14a. A scan in the opposite direction, i.e., from right to left, is also suitable. The magnitude or spread of the laser radiation in the working plane can be determined based on the laser radiation sweeping through the first and / or second slit-shaped aperture openings 14a. The energy or power of the laser radiation can be determined based on the laser radiation passing centrally through the circular aperture opening 14b, allowing the flux in the working plane to be determined from the determined information. Furthermore, the scanner movement can be calibrated based on the movement through the two slit-shaped aperture openings 14a, thus enabling the characterization of the laser radiation and the calibration of the scanner in a single process.

[0155] Optionally, the aperture device may also have two additional slit-shaped aperture openings 14a, arranged perpendicular to the other two slit-shaped aperture openings 14a (shown in dashed lines). The aperture openings can be used to determine the spread of laser radiation in the working plane (vertically in the figure) along another dimension, and can also be used to calibrate scanner movement along that direction.

[0156] Figure 1C An aperture device 10 according to another embodiment is shown, most of which corresponds to Figure 1B The embodiment shown differs from the one described above in that only one vertically extending, slit-shaped aperture opening 14a is constructed to determine the laser's spread, and instead, another vertically extending, slit-shaped aperture opening 18 is constructed to determine the aiming laser's spread. Therefore, the slit-shaped aperture opening 18 is also superimposed on the aiming laser detector 20, enabling the detection of the aiming laser radiation passing through the aperture opening 18 and the determination of the aiming laser radiation's spread in the working plane. This embodiment enables the characterization of the laser radiation flux and the correlation of the aiming laser radiation with the laser radiation in the working plane within a single process.

[0157] Figure 1DAnother alternative embodiment of the aperture device 10 is shown, characterized in particular by its simplicity. The aperture device 10 has only a single aperture opening 14, which is constructed as a rectangular aperture of a predetermined size. As in other embodiments, a photodetector 16 is arranged below the aperture opening 14 or the aperture 12, and the laser radiation passing through the aperture opening is directed onto the photodetector. In particular, the aperture opening 14 is characterized by having two opposing, parallel, and optionally linearly extending edges. Characterization of the laser radiation can be performed using the aperture device 10 according to this embodiment, for example, by guiding the laser radiation above the aperture device 10 in a working plane during a linear scanning movement, such that the laser radiation sweeps across the aperture opening 14. Here, the sweep can optionally be performed such that the movement of the laser radiation during the scan is perpendicular to the two opposing edges of the aperture opening 14. For example, this scanning movement can be performed horizontally or vertically in the aperture opening shown. On the one hand, the spread of laser radiation in the working plane can be determined by scanning the edge of the aperture opening 14, and on the other hand, the scanner can be calibrated (based on a predetermined spacing of the edge). Here, the aperture opening 14 is sized such that the laser radiation is transmitted substantially completely when it passes through the aperture opening 14 centrally. In this way, the energy or power of the laser radiation can also be determined by means of the photodetector 16. Therefore, the flux of laser radiation in the working plane can also be determined using the aperture opening according to this embodiment, and the scanner can be calibrated in the same process.

[0158] If the aiming laser radiation should also be used, then alternatively, another aperture 18 and the photodetector 20 arranged below it can be used to mutually calibrate the processing laser radiation and the aiming laser radiation as described above.

[0159] Figure 2A A schematic cross-sectional view along section line A-A' shown in Figure 1 illustrates an aperture arrangement 10 according to an alternative embodiment. Here, it can be identified that the aperture device has a support element 22 on which an aperture 12 is disposed at the top. The support element 22 supports the aperture 12 in the edge region and forms a cavity below the aperture 12 within the support element 22. A photodetector 16 is disposed in the cavity below the aperture 12 such that the photodetector or detector surface is superimposed on the aperture openings 14a and 14b located above it. If one of the aperture openings 14a and 14b is swept by laser radiation, at least a portion of the laser radiation is transmitted through the corresponding aperture opening 14a, 14b and strikes the photodetector 16 located below it. Here, the aperture 14b is selected in shape and size such that the laser radiation can be transmitted substantially completely. The aperture opening 14a... Figure 2AThe direction of the horizontal extension is significantly smaller than the average diameter of the laser radiation, so that the magnitude of the laser radiation can be determined by scanning through the corresponding aperture opening 14a.

[0160] Figure 2B Another schematic cross-sectional view along section line B-B' shown in Figure 1 is shown. This cross-section intersects laterally with aperture opening 18 and longitudinally with aperture opening 14a. Here it can be identified that aiming laser detectors 20 are arranged on corresponding cantilever arms of support element 22 below aperture opening 18, such that a portion of the aiming laser radiation, as it sweeps across the corresponding aperture opening 18, hits and can be detected by the aiming laser detector 20. According to the illustrated embodiment, the cantilever arm supporting the aiming laser detector 20 or support element 22 is superimposed on a photodetector 16 arranged below it. However, this is irrelevant, because at the illustrated location, the photodetector ultimately only needs to detect the working laser radiation energy transmitted through the aperture opening above it, which can pass unimpeded through aperture opening 14a and the cantilever arm of support element 22. In this way, a particularly compact and space-saving aperture device 10 can be provided, which can also be placed in a working plane with limited space.

[0161] By spaced apart from the aperture opening 12, the photodetector 16 is positioned recessed relative to the aperture 12, which is used to inspect laser radiation in the working plane. This is particularly advantageous for embodiments that focus laser radiation onto the working plane, as the laser radiation thus has a larger diameter in the plane of the photodetector 16 and strikes the photodetector 16 with a correspondingly lower intensity. This reduces the load on the photodetector 16 and / or allows the use of a photodetector 16 with a lower damage threshold. The recessed arrangement also provides the advantage that the emitted laser radiation has a larger diameter, resulting in a larger sensor surface for detecting the laser radiation, thereby improving accuracy and / or reducing sensitivity to local fluctuations in the sensor sensitivity of the photodetector.

[0162] On the other hand, the aiming laser detector 20 is positioned closer to the aperture 12 and thus closer to the working plane. However, since the aiming laser radiation typically has much lower power than the working laser radiation, there is no concern about damage to the aiming laser detector 20 even when positioned close to the working plane.

[0163] according to Figure 3A and 3B The following schematically explains how the spread of laser radiation 24 is determined according to an alternative implementation. Figure 3AA top view of the aperture opening 14a and laser radiation 24 is shown, the cross-section of which is symbolically represented by dashed lines. The laser radiation sweeps across the aperture opening 14a along a scanning direction 200. Here, the scanning direction 200 extends perpendicular to the longitudinal axis of the slit-shaped aperture opening 14a. The aperture opening 14a has a dimension along the scanning direction 200, i.e., its width, which is significantly smaller than the average diameter of the laser radiation 24. Therefore, during the sweep across the aperture 14a along the scanning direction 200, at different time points and at different relative positions of the laser radiation 24 with respect to the aperture opening 14a, a significantly larger portion of the energy or power of the laser radiation is transmitted through the aperture opening 14a, while the remaining portion is absorbed or reflected by the aperture 12.

[0164] exist Figure 3B The diagram shows an example graph of the detector signal of the photodetector 16 arranged below the aperture opening 14a, the detector signal being proportional to the transmitted energy. The detector signal is plotted on the y-axis in arbitrary units relative to the relative position of the laser radiation 24 with respect to the central axis of the aperture opening 14a, and on the x-axis. If the laser radiation reaches the aperture opening 24, the detector signal first rises at subsequent measurement points until it reaches its maximum value at position x0, where the midpoint of the laser radiation 24 lies on the central axis of the aperture opening 14a. If the laser radiation continues to move along the scanning direction 200, the detector signal decreases again. To reliably determine the spread of the laser radiation in the scanning direction, the scanning direction must extend perpendicular to the longitudinal axis of the aperture opening 14a. Therefore, the detector signal follows a curve symmetrical about position x0, which resembles a Gaussian bell curve and corresponds to the convolution of the laser radiation profile along the scanning direction with the slit width, enabling the determination of the radiation profile along the dimension of the scanning direction. For a finite-width aperture 14a, the actual expansion of the detector signal and the laser radiation 24 deviate from the ideal Gaussian curve. To determine the expansion of the laser radiation, the exact expansion or width of the aperture 14a is required. Then, the expansion of the laser radiation can be calculated as the sum of the error function erf(x). Furthermore, the average diameter (FWHM) is... Figure 3B It is drawn in the middle and represented by d.

[0165] Figure 4 A laser processing system 30 for ocular refractive surgery is shown according to an alternative embodiment. The laser processing system 30 is configured as a treatment instrument and is used, for example, to perform refractive correction at a patient's eye (not shown) by means of refractive surgery utilizing laser radiation or processing laser radiation 24. For this purpose, the laser processing system 30 has a laser or laser source 32 that emits laser radiation 24. The laser radiation 24 is configured to act on the cornea of ​​the eye to alter the refractive effect of the cornea.

[0166] The laser radiation 24, or processed laser radiation 24, output by laser 32 along optical axis A1, is directed onto beam splitter 34, which guides the laser radiation 24 onto a deflection unit 36 ​​configured as a deflection device 36. The deflection unit 36 ​​has two scanning mirrors 38 and 40, which are rotatable about mutually orthogonal axes, thereby deflecting the laser radiation 24 in two dimensions. An adjustable projection optics device 42 focuses the laser radiation 24 onto the object being treated, or onto or into the eye to be treated. Here, the projection optics device 42 has two lenses 44 and 46.

[0167] For treatment, the eye to be treated is positioned within the working plane 300, allowing the laser radiation to be focused onto the eyepiece. However, in Figure 4 In this design, an aperture device 10 is arranged in the working plane 300, which allows for the inspection of focused laser radiation. For eye treatment, the laser radiation can first be inspected using the aperture device 10, then the aperture device 10 can be removed, and eye treatment can then begin in the working plane. In this manner, the laser radiation can be inspected at locations where the laser radiation is also used for treatment or manipulation.

[0168] The laser processing system also includes a control unit 48. The control unit 14 optionally determines the position of the focal point 50 perpendicular to the optical axis A1 (via scanning mirrors 38 and 40) and along the direction of the optical axis A1. The control unit 14 also reads the detector 52, which serves, for example, as a monitoring unit and for monitoring the processing. Additionally, the laser processing system 30 can have other sensors and / or detectors, particularly internal energy sensors or energy detectors, however these are not shown in the figures. For example, an energy sensor can be arranged after the beam splitter 38 to determine the energy transmitted through the beam splitter. Furthermore, the control unit 48 is connected to the aperture device 10 and is designed to: in particular read and / or control the photodetector 16 and, optionally, the aiming laser detector 20. If the aperture device 10 is movably constructed and arranged, such that scanning the aperture opening with laser radiation can be achieved, for example, by displacing the aperture device 10 in the working plane, it is advantageous that a corresponding displacement unit is also connected to and controlled and / or adjusted by the control unit 48.

[0169] The following describes, by way of example, a method for inspecting laser radiation from a laser processing system, but the claimed implementation is not limited to this example.

[0170] The calibration of a laser system or the inspection of laser radiation is performed in multiple steps, but these steps can also be combined with fully parameterizable laser control in scanning mode:

[0171] a) Calibrate the offset device used to generate scan movement;

[0172] b) Determine the diameter of the laser radiation and calculate the target value of the laser radiation flux in the working plane for that diameter;

[0173] c) Measure the laser energy of the processed laser radiation and calculate the flux from the independent magnitudes of the laser radiation energy and the average diameter of the laser radiation. Compare the target value with the actual value;

[0174] d) Adapt energy and repeat b) and c).

[0175] e) Calibrate the laser radiation offset, which describes the position of the laser radiation in the working plane when the scanning mirror or offset device is in the neutral position.

[0176] f) Calibrate the aiming laser radiation offset;

[0177] g) Calibrate eye tracker offset.

[0178] The following explanation is for reference. Figure 5 conduct, Figure 5 This corresponds to the aperture arrangement according to the embodiment shown in Figure 2. For clarity, specific markings are assigned to each aperture opening, such as in... Figure 5 It can be identified in the text.

[0179] Step 1) Adjust the position and orientation of the aperture assembly, which includes the aperture, photodetector, and two aiming laser detectors, in the working plane so that the aperture assembly is positioned perpendicular to the incident direction of the laser radiation. Orientation can be achieved using typical adjustment aids for handling lasers. For example, adjustment aids are spacing lasers, camera image / video relays, and / or distance sensors.

[0180] Step 2) The laser radiation moves sequentially over the slit or aperture openings ExH1 and ExH2 with known step sizes ds. This yields an approximately Gaussian curve for each scan over one of the aperture openings. For both aperture openings, the following variables are derived by fitting a known convolution function from the intensity curves or detector signals and aperture geometry: center x0, average diameter d (FWHM). However, optionally, the amplitude A and offset y0 of the detector signal are not necessarily used, but are recorded for consistency checks.

[0181] Step 3) Compare the variable Distanz_H_Ist = x0(ExH2) - x0(ExH1) with the known spacing of the aperture slits ExH1 and ExH2 (spacing 100a in Figure 1), and then check the magnification factor gain_H = Distanz_HIst / Distanz_H_Soll for horizontal deflection using the scanner or offset device. If a deviation between the new and old gains exceeds a specific tolerance range, the magnification factor should be adjusted and steps 1-3 repeated.

[0182] Step 4) The variable Offset_Ex_H = x0(ExH2) + x0(ExH1) describes the offset between the centroid position of the laser radiation processing device and the center of the aperture in the scanner's neutral position. Compare this offset to the tolerance range. If a deviation exists, the sensor position should be checked using the mechanism in Step 1). If the position is correct, there is an off-center in the scanner or the offset device, and calibration should be stopped.

[0183] Step 5) Compare the average diameters of the laser radiation d(ExH1) and d(ExH2) individually with their tolerance ranges and preset values. This is to further calculate and form the average value dH. The target fluence Fsoll can be adapted from the value dH.

[0184] Step 6) Repeat steps 2 through 4 for the vertical line based on the aperture openings ExV1 and ExV2. This provides the values ​​dV, Offset_Ex_V, and gain_V.

[0185] Step 7) The processing laser radiation is redirected through a central aperture (14b in Figure 1) constructed as a circular aperture in a small area at or around the scanner's neutral position, and the transmitted energy is measured. This provides a measurement value E. Mess The measured value can be converted into the actual energy value using the sensor's own calibration coefficient. This provides the value E. ist .

[0186] Step 8) From E ist Calculate the actual injection volume F using the values ​​of dH and dV. ist Actual betting volume vs. target betting volume F soll A comparison is made. If there is a deviation between the actual injection volume and the target injection volume, the energy of the processing laser is adapted, and steps 2 to 7 are repeated using the new laser energy setting.

[0187] Step 9) Using an eye tracker, determine the offset of the central aperture opening ExL (14b in Figure 1) in the vertical and horizontal directions, which is constructed as a circular aperture, and determine the parameters Offset_Tracker_V and Offset_Tracker_H. Compare the offset with the tolerance range determined for this purpose.

[0188] Step 10) Scan the aiming laser over the VisH structure and evaluate the center of gravity x0. ist The position of (VisH). Because the scanner in step 3 is calibrated in the magnification factor, the difference between the target position and the actual position of the radiation centroid is obtained only from the offset of the aiming laser radiation: Offset_Vis_H = xO(VisH) - x0 soll (VisH). Offset_Vis_H is compared to the tolerance range defined for it.

[0189] Step 11) Repeat step 10 for the vertical direction. Offset_Vis_V.

[0190] Figure 6A and 6B A schematic diagram of a laser processing system 1000 according to an alternative implementation is shown, using two different operating modes characterizing laser radiation 1002.

[0191] Here, the laser processing system 1000 has a laser source 1004 that emits laser radiation 1002. This laser radiation first passes through a radiation shaping device 1006, in which the laser radiation 1002 is shaped to a desired form. After the radiation shaping device 1006, the laser radiation propagates through a deflection device 1008 or a scanning device, by which it can deflect the laser radiation 1002, allowing the laser radiation 1002 to move within a working plane 2000 or a control plane 2002 to perform the desired treatment on the object being processed, such as, for example, eye treatment. The radiation shaping device 1006 is optionally configured to focus the laser radiation 1002 onto the working plane 2000 or the control plane 2002.

[0192] Between the radiation shaping device 1006 and the deflection device 1008, a beam splitter 1010 is arranged in the radiation path of the laser radiation 1002. The beam splitter branches a small portion of the laser radiation 1002 or laser energy and delivers it to the internal energy sensor 1012. For example, the beam splitter 1010 can be configured such that it reflects approximately 10% of the laser radiation energy and delivers the remaining energy. Beam splitters with different ratios can also be used, as long as there is still sufficient energy delivered for treatment or processing in the working plane. The energy sensor 12 determines energy parameters based on the delivered portion of the laser radiation, from which the energy and / or power of the entire laser radiation can be derived. Optionally, the laser processing system is designed to continuously and / or periodically determine the energy parameters during operation of the laser processing system 1000 by means of the energy sensor 1012.

[0193] Figure 6A The diagram illustrates a laser processing system in a first operating mode for characterizing laser radiation 1002, wherein a calibration device 1014 is arranged in a working plane 2000 and calibration parameters are determined for characterizing laser radiation 1002. These calibration parameters enable the determination of the flux of laser radiation 1002 in the working plane 2000.

[0194] Figure 6B A laser processing system 1000 is shown in a second operating mode for characterizing laser radiation 1002, wherein a calibration device 1014 is arranged in a control plane 2002. The control plane 2002 also contains the calibration device 1014, which is located within the laser processing system 1000. Here, control parameters in the control plane 2002 are determined by means of the calibration device 1014. These control parameters can optionally be determined in the same manner as the calibration parameters, except that they are determined in the control plane 2002, not the working plane 2000. The control parameters can determine the flux of laser radiation 1002 in the control plane 2002. Here, laser radiation 1002 is deflected by a deflection element 1016, so that the laser radiation does not strike the working plane 2000 but strikes the control plane 2002. For this purpose, the deflection element 1016 can be configured as a mirror, for example, and moved from the laser processing system 1000 into the radiation path of laser radiation 1002. For example, the deflection element can be arranged displaceably or pivotally so that it can be moved into and out of the radiation path. After the control parameters are determined, the deflection element 1016 can be removed from the radiation path again so that the laser radiation 1002 can propagate into the working plane again.

[0195] Optionally, the determination of the control parameters is performed immediately after the determination of the calibration parameters in order to minimize the risk of changes during this period.

[0196] Based on the calibration and control parameters, the laser processing system 1000 can then determine the deviation coefficient, which allows the two parameters or their measured values, such as the calculated flux value, to be correlated.

[0197] Then, the laser processing system 1000 can perform the inspection of the laser radiation 1002 in the following manner: that is, only the control parameters are determined, the control parameters are compared with the target value, and the energy of the laser radiation 1002 is checked according to the energy parameters to see if the energy also corresponds to the target value. Thus, the inspection of the laser radiation 1002 can be achieved even if the working plane cannot be used to determine the calibration parameters.

[0198] In the processing mode that utilizes laser radiation to process the object, the deflection element 1016 is also arranged outside the radiation path, i.e., for example in... Figure 6AAs shown, however, in the processing mode, the calibration device 1014 is not arranged in the working plane 2000, but the processing object (not shown) is arranged in the working plane.

[0199] Figure 7A and 7B A schematic diagram of the processing head 1020 of a laser processing system 1000 according to an optional embodiment is shown with two operating modes for characterizing laser radiation 1002.

[0200] Here, the processing head 1020 is designed to emit laser radiation 1002, such that the laser radiation propagates along the optical axis A1 and is incident on the working plane 2000 or the control plane 2002.

[0201] Furthermore, the laser processing system 1000 has a device at the processing head 1020 such that the calibration device 1014 can be selectively arranged in the working plane 2000 and the control plane 2002, and the deflection element 1016 can be selectively positioned in or outside the radiation path or optical axis A1 of the laser radiation 1002. For this purpose, the device has a driver 1022 and a guide 1024 to move the deflection element 1016 from a position outside the radiation path (…). Figure 7A The position placed in the radiation path ( Figure 7B And vice versa.

[0202] Furthermore, the laser processing system 1000 has a pivoting device for pivoting the calibration device 1014 from the working plane 2000 to the control plane 2002 and vice versa. For example, for this purpose, the calibration device 1014 can be fixed at a pivot joint 1026 via an arm 1024, which is pivotable about the pivot joint 1026, as indicated by the curved arrow 2004. Clearly, the device is constructed and / or arranged such that laser radiation is not obstructed or blocked by the device or its components in any operating mode.

[0203] For example, in operating modes for processing objects or for processing eyes, the calibration device 1014 can pivot into the control plane and the deflection element 1015 can be arranged outside the radiation path.

[0204] The calibration of laser radiation 1002 of laser processing system 1000 is described below with reference to examples, but the claimed implementation is not limited to the following examples:

[0205] In particular, the following explanation relates to the association between calibration performed using a calibration device in the working plane (external location) and inspection performed using a calibration device in the control plane (internal location):

[0206] 1) First, the laser radiation is calibrated or characterized using a calibration device in the working plane (to determine calibration parameters) without the need for additional optical or deflection elements. Here, the energy parameter is also determined as a reference value (Eint, 0) for the internal energy sensor according to the calibration method, and the laser energy is adjusted until the actual fluence F. ist_extem Within the tolerance of the target injection volume (F) target，extern ).

[0207] 2) Next, the test is performed directly on the same calibration device, but in the control plane within the laser processing equipment, optionally at a constant working distance relative to the laser source aperture, and the control parameters are determined. This can be achieved, for example, by a rigid pivoting mechanism or by mechanical or magnetic stops. Here, additional optical elements are used as deflectors to completely redirect the laser radiation to the internal position of the calibration device in the control plane. The additional deflector (in the radiation direction) is arranged after the last optical element in the radiation path.

[0208] Using an internal flux measurement (which is explicitly not a calibration) under an energy setting that is fixed relative to the energy found in step 1) (i.e., at E... int，0 In the case of [the situation], determine the control parameters and provide the injection rate value F. ist，intern .

[0209] Due to the characteristics of the additional deflecting element, such as the reflectivity of the deflecting element constructed as a mirror, this fluence value differs from the fixed value F. target，extern From this, the deviation coefficient can be determined, and using the deviation coefficient, these effects can be calculated:

[0210] R=F ist，intern / F target，extern .

[0211] 3) Subsequently, the characterization of the laser radiation or the calibration of the laser system can be performed solely via an internal location (i.e., without placing the calibration device in an external location), i.e., via control parameters, wherein the target value of the flux is calculated via the deviation coefficient R determined in 2).

[0212] F target，intern =R F target，extern .

[0213] 4a) The calibration interval used to determine the deviation coefficient R (steps 1 and 2) can be determined such that no degradation of the additional deflection element affects the calibration accuracy (e.g., by determining an appropriate time interval / number of tests).

[0214] 4b) Ideally, possible degradation of the deflection element, such as a decrease in reflectivity, can be checked by continuously monitoring control parameters relative to the energy sensor in the laser arm, i.e., the energy parameter: this can optionally be done by continuously comparing the measurement signal F from the calibration device. ist，intern and E int，aktuell This is to be performed (in the case of a calibration device with continuous measurements, the calibration device cross-calibrates using the current measurements from an internal energy sensor).

[0215] 4c) Independently, potential degradation of the deflection element can be monitored in a different spectral range than that of the processing laser. For this purpose, measurements of the transmissivity or reflectivity of the deflection element can be performed regularly. Since degradation can typically occur in the optical element at this location, i.e., the last optical element before the working plane, at the coating side (caused by the processing laser) or through contamination, such as droplets of rinsing fluid from refractive surgery, it can also be determined in other spectral ranges. For example, degradation can be assessed by means of an illumination device and a camera and / or by using a scanned aiming laser, which is typically present in such systems.

[0216] Of course, it is possible to identify only the degradation in this manner, and quantification can be achieved using the methods proposed in 4b) or steps 1)-2). However, identification can be used alone to: deactivate the laser treatment system and / or terminate treatment and / or output corresponding instructions requiring examination.

[0217] Figure 8A A schematic diagram of the device 3010 used to characterize laser radiation is shown (see Figure 8B The apparatus 3010 has a test object holder 3012 that holds the test object 3014 in a predetermined position. Here, the test object holder 3012 is designed such that laser radiation can be incident from the side opposite to the test object holder 3012 onto the surface of the upper side 3014a of the test object 3014.

[0218] A sensor 3016, comprising a measuring device 3018 (not shown), is arranged below the test object 3014, on the side facing the test object holder 3012. In addition to the sensor 3016, the measuring device 3018 may also include other elements, such as control and / or evaluation units.

[0219] Sensor 3016 is configured as a confocal colorimetric sensor, constructed and arranged such that electromagnetic radiation in the visible and / or infrared spectral range is incident on the test object 3014 via the lower side 3014b along the optical axis 3100 of sensor 3016. This electromagnetic radiation is hereinafter referred to as the measurement light. The incident measurement light is focused, as is common in confocal colorimetric sensors, such that different spectral components or different wavelengths are focused using different focal lengths, and correspondingly, at different depths of penetration into the test object 3014. Typically, shorter wavelength spectral components are focused using a shorter focal length, while longer wavelength components are focused using a longer focal length, although other embodiments are equally suitable. The light cone of the focused measurement light is exemplarily shown by dashed lines.

[0220] Using sensor 3016, the thickness of the test object 3014 can be measured by detecting, evaluating, and comparing the proportions of light reflected and / or scattered at the lower side 3014b and the upper side 3014a. Since the different spectral components have different depths of penetration, the two reflections or scatterings at the upper side 3014a or lower side 3014b are different. Therefore, the distance between the reflecting plane or scattering plane and sensor 3016 can be determined from the different spectral compositions of the two reflections or scatterings, and the thickness of the test object 3014 can be calculated from this distance.

[0221] Needless to say, the test object 3014 must be at least partially, ideally almost completely, transparent to the measurement light. For example, the test object 3014 is constructed of polymethyl methacrylate (PMMA) because PMMA has suitable transparency to the measurement light and can also be processed by means of ultraviolet (UV) laser radiation.

[0222] The following portion of the test object 3014 is referred to as the test portion 3020, which is measured by the sensor 3016, or the thickness of the test object 3014 is determined at this portion. To determine the thickness of the test object 3014 also at other locations on the test object 3014 or at other test portions 3020, the test object 3014 can be scanned at least partially by means of relative movement between the test object 3014 and the sensor 3016. Here, the thickness of the test object 3014 is the spatial extension of the test object 3014 parallel to the optical axis 3100. The thickness can vary at different portions of the test object 3014. To measure the thickness at multiple test portions 3020, the sensor 3016 and / or the test object holder 3012 can move in one or preferably two dimensions perpendicular to the optical axis 3100, as indicated by arrows 3200 and 3300.

[0223] Figure 8B Showing according to Figure 8AThe apparatus of the embodiment is shown, wherein laser radiation 3022 is additionally shown, by means of which material removal is being performed or has been performed on the upper side 3014a of the test object 3014. Laser radiation 3022 optionally has a center wavelength in the ultraviolet spectral range (e.g., 193 nm). Optionally, laser radiation 3022 is provided by an argon fluoride (ArF) excimer laser, although other laser sources are also suitable for providing suitable laser radiation 3022.

[0224] According to the embodiment shown, laser radiation 3022 is incident on the test object 3014 along an optical axis 3102, wherein the optical axis 3102 of the laser radiation 3022 is parallel to the optical axis 3100 of the sensor 3016. According to other embodiments, the laser radiation can also be incident at different angles.

[0225] The test object 3014 is at least partially constructed of a material suitable for at least partially absorbing laser radiation. This achieves material removal at the test object 3014 by means of laser radiation 3022. As mentioned above, the test object is optionally constructed of PMMA because it has a high optical density in the ultraviolet spectral range and is also sufficiently transparent to the measurement light. Here, optionally, the thickness of the test object 3014 is selected such that after material removal, the thickness of the test object 3014 is sufficient to characterize the laser radiation 3022, so as to prevent the laser radiation from penetrating to the sensor 3016. Thus, damage at the sensor caused by laser radiation 3022 can be avoided.

[0226] If the position of the sensor 3016 and the focal position of its axis 3100 relative to the laser radiation 3022 and the position of its axis 3102 are known or preset, for example by a suitable stop at the laser above the test object holder 3012, then sufficient position of the test part 3020 relative to the laser radiation 3022 can be ensured before thickness measurement, for example, even if the test object 3014 is correctly inserted into the test object holder 3012.

[0227] Due to material removal by laser irradiation 3022, the thickness of the test object 3014 changes at the treated area. This thickness change can be determined using sensor 3016, for example, before and after treatment with laser irradiation 3022 and / or before and during treatment. Due to the high sensitivity of the confocal colorimetric sensor 16, thickness changes from 100 nm or even smaller can be selectively determined.

[0228] Optionally, for each test site 3020, material removal by laser radiation 3022 is performed with a predetermined number of bombardments or laser pulses. By varying the thickness of the test object 3014, the material removal per pulse or bombardment can be determined, since the number of bombardments or pulses applied to the test site 3020 is known. Other test sites 3020 can also be subjected to different numbers of pulses or bombardments to obtain additional measurement data by comparing material removal or thickness variations at different test sites, and to more reliably determine thickness variations.

[0229] Figure 9 Another embodiment is shown, wherein laser radiation (not shown) is characterized during application to the cornea 3024 of the human eye 3026. In other words, according to this alternative embodiment, the cornea 3024 functions as the test subject 3014 and can thus also be regarded as the test subject 3014 in the sense of this patent application.

[0230] According to this alternative embodiment, the cornea 3024 is refractively corrected by means of laser radiation (not shown), whereby the laser radiation is incident on the cornea 3024 along the optical axis 3102, as indicated by arrow 3104.

[0231] Beam splitter 3028 is positioned above cornea 3024 in the beam path of the laser radiation, i.e., on the optical axis 3102. According to this embodiment, the beam splitter is tilted at 45° relative to the optical axis 3102; other angles are also possible according to other embodiments. Optionally, beam splitter 3028 is almost completely transparent at the center wavelength of the laser radiation, allowing the laser radiation to pass through the beam splitter almost unimpeded without significant power loss.

[0232] Conversely, beam splitter 3028 may optionally be highly reflective of the wavelength of the measurement light emitted by confocal chromaticity sensor 3016. Alternatively or additionally, beam splitter 3028 can also be designed as a polarization beam splitter, which focuses the processing laser and measurement light of different polarizations together. According to an alternative embodiment, beam splitter 3028 is configured as a temporary foldable reflector for the measurement light, so as to enable the measurement or characterization of laser radiation 3022 between individual pulses or pulse sequences of laser radiation 3022.

[0233] According to this embodiment, the optical axis 3100 of the sensor 3016 is arranged perpendicular to the optical axis 3102 of the laser radiation. Here, the measurement light is directed onto the beam splitter 3028, which deflects the measurement light onto the test site 20 on the cornea 3024, where the test site is treated with laser radiation.

[0234] Light reflected and / or scattered at test site 3020 or cornea 3024 is also reflected by a beam splitter and projected back to sensor 3016. Sensor 3016 is then able to detect the projected measurement light. Measurement device 3018, which includes a control and evaluation unit 3032 in addition to the sensor, calculates the change in corneal thickness at test site 3020 based on the data obtained from the sensor, and is able to characterize the laser radiation based on this. Equally feasible position testing of the corneal surface relative to the focal point of sensor 3016 and / or laser radiation 3022 facilitates accurate processing and thickness measurement. If, in the event of an error, the cornea moves out of the predetermined working area on axis 3100, readjustment and / or suspension and / or at least interruption of laser processing and thickness measurement is possible.

[0235] Alternative embodiments are not shown, in which the sensor 3016 is positioned laterally to the incident laser radiation 3022 to measure the test site 3020 treated by the laser radiation 3022, without having to superimpose the light of the laser radiation 3022 and the sensor 3016 by means of optical components such that, for example, axes 3100 and 3102 form an angle to intersect at the test site 3020, or without intersecting by gradually displacing the sensor 3016 laterally to measure the test site 3020 previously treated by the laser radiation 3022. According to an alternative embodiment, the measuring device is also connected to a control device (not shown) for the laser source and can intervene in the laser source in an adjustable and / or controlled manner as needed, using data from the laser radiation characterization, for example, to increase and / or decrease the power of the laser radiation.

[0236] Therefore, the illustrated implementation allows for real-time characterization of laser radiation, which can be used to adjust the laser radiation.

[0237] Figures 10A to 10C Schematic diagrams are shown of various alternative implementations for providing test object 3014.

[0238] according to Figure 10A In one embodiment, multiple block-shaped test objects 3014 are arranged on a substrate 34. For example, the substrate 3034 can be constructed as a flexible film. For example, in this embodiment, the test objects 2014 are automatically conveyed to a test object holder by moving the substrate 3034, for example, via rollers.

[0239] according to Figure 10BIn the embodiment shown, the test object 3014 itself is constructed as a membrane 36. By appropriately tracking the membrane 36, different portions of the membrane can be used as test sites 3020. Here, the membrane 3036 should be chosen to be thick enough to prevent laser radiation 3022 from penetrating the membrane 3036 and to prevent laser radiation from hitting the sensor 3016 that may be arranged below the membrane.

[0240] according to Figure 10C In the embodiment shown, the test object 3014 is constructed in the form of a disk 3036, wherein the disk is significantly larger than a single test site 3020. By displacing and / or rotating the disk 36, different sites of the disk 3036 can be selected for applying laser radiation, thereby enabling multiple test sites 3020, optionally more than 1000 test sites 3020, to be placed on the test object 3014 or on the disk 3028.

[0241] List of reference numerals in the attached diagram:

[0242] 10. Aperture device

[0243] 12 aperture

[0244] 14, 14a, 14b: Aperture openings used for working laser radiation.

[0245] 16 Photodetectors

[0246] 18. Aperture opening for aiming laser radiation

[0247] 20 Aiming laser detector

[0248] 22 Load-bearing elements

[0249] 24 Laser radiation

[0250] 30 Laser processing system

[0251] 32 laser sources

[0252] 34 beam splitters

[0253] 36. Deviation device

[0254] 38 Scanning mirror

[0255] 40 Scanning mirror

[0256] 42 Projection Optical Device

[0257] 44 Lenses

[0258] 46 Lenses

[0259] 48 Control Unit

[0260] 50 Focuses

[0261] 52 Detectors used for monitoring the processing.

[0262] The predetermined spacing between the two aperture openings 14a of 100a and 100b

[0263] 200 Scanning direction

[0264] 300 working plane

[0265] 1000 Laser Processing System

[0266] 1002 laser radiation

[0267] 1004 laser source

[0268] 1006 Beamforming Device

[0269] 1008 Deviation Device

[0270] 1010 beam splitter

[0271] 1012 Energy Sensor

[0272] 1014 Calibration Device

[0273] 1016 Deflection Element

[0274] 1018 A device for moving a deflection element

[0275] 1020 processing head

[0276] 1022 drive

[0277] 1024 Guiding Device

[0278] 1026 Pivot joint

[0279] 1028 arms

[0280] 2000 working plane

[0281] 2002 Control Plane

[0282] 2004 Pivot Direction

[0283] 3010 Equipment for characterizing laser radiation

[0284] 3012 Test Object Retainer

[0285] 3014 Test Object

[0286] 3014a Top side of the test object

[0287] 3014b The bottom of the test object

[0288] 3016 sensor

[0289] 3018 Measuring Device

[0290] 3020 Test Site

[0291] 3022 laser radiation

[0292] 3024 cornea

[0293] 3026 eyes

[0294] 3028 beam splitter

[0295] 3032 Control and Evaluation Unit

[0296] 3034 substrate

[0297] 3036 membrane

[0298] 3038 disks

[0299] Optical axis of sensor 3100

[0300] 3102 Optical axis of laser radiation

[0301] 3200 Sensor Movement Direction

[0302] 3300 Test object retainer movement direction

[0303] AA' Cross-sectional orientation index

[0304] Indicators of BB' cross-sectional orientation

[0305] A1 is the optical axis of laser radiation.

Claims

1. A method for characterizing at least one laser radiation (24) of a laser processing system (30), the method comprising: a) An aperture device (10) having a plurality of aperture openings (14) is provided in the working plane (300) of the laser processing system (30), such that the aperture openings (14) extend within the working plane (300); b) Scan the laser radiation (24) above the aperture device (10) along a scanning direction (200) parallel to the working plane (300), such that the laser radiation (24) sequentially and at least partially sweeps through at least two aperture openings (14) in time. c) Calculate the energy of the laser radiation (24) transmitted through the aperture opening (14) during the scanning process; d) Determine the spread of the laser radiation (24) along the scanning direction (200) based on the energy transmitted through the first aperture (14a) of the plurality of aperture openings (14) obtained from the laser radiation (24), and determine the energy parameters of the laser radiation (24) based on the energy transmitted through the second aperture opening (14b) of the plurality of aperture openings (14) obtained from the laser radiation (24); The first aperture opening (14a) has a predetermined extension along the scanning direction (200) that is smaller than the average diameter of the laser radiation (24) in the working plane (300), and the second aperture opening (14b) has an extension that is larger than the laser radiation (24) in the working plane (300) and is designed to transmit the laser radiation (24) substantially completely.

2. The method according to claim 1, wherein, The aperture device (10) further includes a third aperture opening of a plurality of aperture openings (14), the third aperture opening having a predetermined extension along the scanning direction (200) smaller than the average diameter of the laser radiation (24) in the working plane (300), and the third aperture opening being arranged along the scanning direction (200) at a predetermined spacing (100a, 100b) from the first aperture opening (14a), and wherein the method further includes: - The adjustment parameters of the laser processing system (30) are determined by using a predetermined distance (100a, 100b) between the third aperture opening and the first aperture opening (14a).

3. The method according to claim 2, wherein, The spread of the laser radiation (24) along the scanning direction (200) is also determined based on the energy transmitted through the third aperture opening of the laser radiation (24), and optionally includes the average value of the spread of the laser radiation (24) formed based on the first aperture opening and the third aperture opening.

4. The method according to any one of claims 1 and 2, wherein, The laser radiation (24) is scanned in a first scanning section and a second scanning section, wherein the scanning direction (200) in the first scanning section extends along a first dimension parallel to the working plane (300), and the scanning direction (200) in the second scanning section extends along a second dimension parallel to the working plane (300).

5. The method according to claim 4, wherein, The first aperture opening (14a) has a predetermined extension along the scanning direction (200) in the first scanning section, and wherein the aperture device (10) has an additional aperture opening of a plurality of aperture openings (14), the additional aperture opening having a predetermined extension along the scanning direction (200) in the second scanning section that is smaller than the average diameter of the laser radiation (24) in the working plane (300).

6. The method according to claim 5, wherein, Multiple aperture openings (14) include at least two aperture openings for each scanning segment, the at least two aperture openings having a predetermined extension along the respective scanning direction that is smaller than the average diameter of the laser radiation (24) in the working plane (300), and arranged with a predetermined spacing (100a, 100b) between them along the respective scanning direction (200).

7. The method according to any one of claims 1 and 2, wherein, The laser radiation (24) and the aiming laser radiation of the laser processing system (30) are characterized by the method described above.

8. The method according to any one of claims 1 and 2, further comprising determining the flux and / or intensity of the laser radiation (24) in the working plane (300) using the calculated spread of the laser radiation (24) and the calculated energy parameters of the laser radiation (24).

9. The method according to any one of claims 1 and 2, further comprising adjusting the laser parameters and repeating steps b) to d) after adjusting the laser parameters.

10. An aperture device (10) for characterizing laser radiation (24) of a laser processing system (30), wherein, The aperture device (10) can be arranged in the working plane (300) of the laser processing system (30), and the aperture device includes: - An aperture (12) with multiple aperture openings (14); - A first aperture opening (14a) of a plurality of aperture openings (14), the first aperture opening having a predetermined extension along the scanning direction (200) of the laser radiation (24) smaller than the average diameter of the laser radiation (24) to be inspected in the working plane (300). - A second aperture (14b) of a plurality of aperture openings (14), the second aperture opening having an extension greater than the laser radiation (24) to be inspected, and designed to transmit the laser radiation (24) substantially completely. - At least one photodetector (16) is arranged such that at least a portion of the laser radiation (24) transmitted through the aperture opening (14) in the working plane (300) can be detected by means of the photodetector (16). The aperture device (10) has a plurality of slit-shaped aperture openings, each slit-shaped aperture opening having a predetermined width corresponding to a predetermined expansion, and the slit-shaped aperture openings are arranged in pairs with a predetermined spacing (100a, 100b) between them.

11. The aperture device (10) according to claim 10, wherein, The aperture device (10) is designed to absorb and / or reflect the portion of the laser radiation (24) that is not transmitted through the aperture opening (14).

12. The aperture device (10) according to claim 10 or 11, wherein, The first aperture opening (14a) is slit-shaped, and the predetermined extension corresponds to a predetermined width of the slit, and / or The second aperture opening (14b) is constructed as a circular hole and has an extension that substantially corresponds to the extension of the laser radiation (24).

13. The aperture device (10) according to any one of claims 10 and 11, wherein, The aperture (12) and the photodetector (16) are constructed in parallel, one above the other, and optionally, the aperture (12) and the aiming laser detector are constructed in parallel, one above the other.

14. A laser processing system (30) for processing an object in a working plane (300) by means of laser radiation (24), the laser processing system comprising: - A laser source (32) for providing laser radiation (24); - A deflection device (36) is capable of moving the laser radiation (24) within the working plane (300) perpendicular to the propagation direction of the laser radiation by means of the deflection device; - The aperture device (10) according to any one of claims 10 and 11, wherein the aperture device (10) is arranged in the laser processing system (30) for characterizing the laser radiation (24) such that the aperture opening (14) is arranged in the working plane (300).

15. The laser processing system (30) according to claim 14, wherein, The laser processing system (30) is configured to: - The laser radiation (24) is scanned above the aperture device (10) along a scanning direction (200) parallel to the working plane (300) by means of the offset device (36), such that the laser radiation (24) at least partially sweeps across the aperture opening (14). - The energy of the laser radiation (24) transmitted through the aperture opening (14) is determined during the scanning process by means of a photodetector (16); - The extent of the laser radiation (24) along the scanning direction (200) is determined based on the energy transmitted through the first aperture opening (14a) according to the laser radiation (24); and - The energy parameters of the laser radiation (24) are determined based on the energy transmitted through the second aperture opening obtained from the laser radiation (24).

16. The laser processing system (30) according to claim 15, wherein, The laser processing system (30) is configured as a laser treatment system for performing ophthalmic surgery on the eye.

17. A method for characterizing laser radiation (24) of a laser processing system (30), comprising: a) Provide an aperture device with an aperture opening in the working plane of the laser processing system, such that the aperture opening extends in the working plane, wherein the aperture device has at least two opening edges that are opposed at a predetermined distance and extend in parallel, the opening edges defining the aperture opening, and the aperture opening is larger than the laser radiation (24) in the working plane and is designed to transmit the laser radiation (24) substantially completely. b) Scan the laser radiation (24) on the aperture device along a scanning direction parallel to the working plane, such that the laser radiation (24) sequentially and at least partially sweeps over the first opening edge of the two opening edges, the aperture opening, and the second opening edge of the two opening edges in time; c) Determine the energy of the laser radiation (24) transmitted through the aperture opening during the scanning process; d) Determine the extent of the laser radiation (24) along the scanning direction based on the curve of the energy transmitted when the laser radiation (24) sweeps across the edge of the first opening and / or the edge of the second opening, and determine the energy parameters of the laser radiation (24) transmitted substantially entirely through the aperture opening; e) Determine the adjustment parameters of the laser processing system to calibrate the deviation device by scanning the edges of the openings arranged at predetermined intervals through the laser radiation (24).

18. An excimer laser comprising a device (3010) for characterizing laser radiation (24), said device having an aperture device (10) for characterizing laser radiation (24) of a laser processing system according to any one of claims 10 and 11.

19. A device for refractive corneal correction, comprising the excimer laser according to claim 18.

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