METHOD FOR PERFORMING A SYSTEM TEST OF A LASER PROCESSING SYSTEM, CONTROL UNIT AND LASER PROCESSING SYSTEM

Description

[0001] The present invention relates to a method for performing a system test of a laser processing system, a control unit, and a laser processing system. The invention thus lies particularly in the field of laser processing systems and especially in the field of ophthalmic laser processing systems for eye surgery.

[0002] Ophthalmic laser processing systems are therapeutic systems used in eye surgery. Their flawless operation is essential for successful treatment and for the safety of both the patient and the operator. This often requires automatic or semi-automatic verification of certain properties of the laser processing systems before treatment.

[0003] Proper functioning can also require achieving a certain level of accuracy during therapy. For this purpose, it is sometimes advantageous to implement targeted measures to improve accuracy. This is particularly true when changes to the laser processing system necessitate calibration. Such changes can be caused, for example, by external influences. These changes are especially prevalent when a laser processing system is combined with other medical devices or includes combinable accessories. For instance, the use of a patient interface in the form of a sterile consumable can introduce variability into the system, requiring calibration to compensate for this variability.

[0004] Therefore, before treating an eye with a laser processing system, one or more test procedures and / or system tests, which may include tests and / or calibrations, are often performed to ensure that the laser processing system functions safely and effectively. The individual tests and / or calibrations that comprise a system test are carried out sequentially.

[0005] A system test may include calibration, for example, if the use of the laser processing system involves interchangeable contact lenses that may vary in thickness, diameter, decentering (lateral offset relative to the optical axis), shape (radius of curvature), and / or other properties due to manufacturing tolerances. To improve the achievable precision of the laser processing system and the treatments performed with it, the determined parameters or results of a system test can be used to optimize the control signals for the scanning device.

[0006] There are various options for scheduling a system test or the individual tests and / or calibrations of a system test, for example, immediately after switching on the laser processing system and / or immediately before treatment. It is advantageous to perform all tests and / or calibrations of the system test immediately before using the laser processing system to treat an eye in order to minimize the time interval between the respective tests and / or calibrations and the treatment, during which undesirable changes can occur. Such undesirable changes can be caused, for example, by thermal drift, spontaneous component failures, mechanical changes, or changes in settings due to accidental contact and / or contamination of the contact lens and / or other components.However, performing all system tests and / or calibrations immediately before treatment conventionally requires the patient to be in a state ready for treatment for the entire duration of the system test. This can necessitate the patient remaining in an undesirable, constrained position for the entire duration of the system test, potentially requiring them to wear surgical gowns and / or an eyelid speculum, be medicated, and / or remain attached to the laser processing device, particularly the contact lens. If the system test is of a considerable length, this can negatively impact the patient's well-being or even cause stress.

[0007] WO2012 / 076031A1 describes a laser device for ophthalmic surgery, which is designed to perform a test run with the laser source switched off, in which the scan components, or at least some of them, are controlled according to a predefined test scan pattern. The actual setting state of at least some of the scan components can be measured to calculate the actual position of the beam focus.

[0008] US2002 / 193704A1 describes a device and system for the photodisruption of ocular tissue. This allows for calibration and, optionally, additional energy calibration or further calibration procedures.

[0009] US2007 / 173792A1 describes systems and devices for testing a laser ophthalmic surgery system. A calibration pattern is displayed, and the beam guidance system can also be calibrated with respect to its lateral deflection characteristics.

[0010] The object of the invention is therefore to reduce the time required for a system test of a laser processing system.

[0011] This problem is solved by a method for performing a system test of a laser processing system, a control unit, and a laser processing system with the features of the respective independent claim. Advantageous embodiments are the subject of the dependent claims and the following description.

[0012] In a first aspect, the invention relates to a method for performing a system test of a laser processing system according to claim 1. The method comprises performing a functional test of a control element of the laser processing system. Furthermore, the method comprises determining a variable parameter and ascertaining the influence of the determined variable parameter on an intended laser processing operation using the laser processing system. The performance of the functional test of the control element and the determination of the variable parameter overlap at least partially in time.

[0013] In a further aspect, the invention relates to a control unit for a laser processing system according to claim 14, wherein the control unit is configured to perform a functional test of the control element of the laser processing system as part of a system test of the laser processing system. Furthermore, the control unit is configured to determine a variable parameter and to ascertain the influence of the variable parameter on the intended execution of laser processing using the laser processing system. The control unit is also configured to perform the functional test of the control element and the determination of the variable parameter at least partially overlapping in time and to receive and / or evaluate the resulting measurement data and / or measurement results at least partially simultaneously.

[0014] In another aspect, the invention relates to a laser processing system comprising a control unit according to claim 15.

[0015] A system test is a procedure for verifying and / or ensuring the functionality of the laser processing system. The system test can comprise one or more tests and / or one or more calibrations. A system test can be performed within a continuous period or at several intervals. Optionally, a system test is designed to be automated, particularly by the laser processing system itself. However, according to some embodiments, system tests can also be performed with the assistance of an operator.

[0016] A test is a functional check of a control element using at least one sensor. A calibration is a measurement of one or more properties of a variable element and / or a variable component using at least one sensor, and the derivation of an adjustment of future control signals according to the measured values.

[0017] A laser processing system is a system that enables the processing of an object using laser radiation. In particular, a laser processing system can be configured as an ophthalmic laser processing system and used for the surgical processing or treatment of a human and / or animal patient's eye. Optionally, the laser processing system can be configured as a device for correcting myopia or hyperopia and / or astigmatism of an eye. Specifically, a laser processing system can include a laser source and / or receive a laser beam from an external, separate laser source. The laser source preferably includes, or is configured as, a femtosecond laser and / or a picosecond laser. According to other embodiments, however, the laser source can also include an excimer laser.The laser beam can preferably be provided as a pulsed laser beam, or also as a continuous wave (cw) laser beam.

[0018] A control element is an element that can be controlled and / or regulated. For example, the control element can represent an actuator. Optionally, the control element can be designed as or comprise a controllable optical element, such as an adaptive mirror and / or one or more movable mirrors. In particular, a control element can be designed to control the laser beam of the laser processing system, for example, by selectively deflecting the laser beam. For example, the control element can be designed as a laser beam scanner, i.e., a scanning device, by means of which the laser beam can be adjusted in its position and / or direction of propagation via one or more movable mirrors.

[0019] Determining a variable parameter involves obtaining information about its actual value and / or state, at least at the time of determination. The information obtained regarding the variable parameter is representative of its variable component. For example, this could include information about the actual design of elements and / or components that are subject to change. Alternatively or additionally, it could include other quantities that are not a property of the laser processing system, such as the position and / or orientation of the eye being treated.

[0020] The fact that performing the control's functional test and determining the variable parameter overlap at least partially in time means that they are not performed completely separately. In other words, this means that at least at one point in time, both the control's functional test and the variable parameter determination occur. Optionally, the two processes can also overlap completely, meaning that both begin and / or end at the same time, or that the control's functional test or the variable parameter determination begins and ends while the other process is still in progress.

[0021] The fact that the control unit can receive and / or evaluate the measurement data and / or results at least partially simultaneously means that the processing unit does not have to complete receiving and / or evaluating the first set of measurement data and / or results before receiving and / or evaluating the second set. In other words, multiple sets of measurement data and / or results can be received and / or processed by the control unit at least partially in parallel. This may place corresponding hardware demands on the control unit, particularly regarding processor performance and / or RAM, to enable the parallel reception and / or evaluation of multiple signals and / or data.

[0022] The invention offers the advantage that at least the functional testing of the control element, the determination of the variable parameter, and the assessment of its influence on the intended laser processing can be performed at least partially simultaneously, thus reducing the time required for the system test. In other words, a test and a calibration within the system test are performed at least partially concurrently. Therefore, the invention offers the advantage that a larger proportion, or even all, of the tests and / or calibrations of the system test can be performed immediately before using the laser system, without exceeding a timeframe acceptable to the patient and / or user.

[0023] The invention also offers the advantage that a division of tests and / or calibrations, which are carried out immediately before processing or treatment using the laser processing system, and other tests and / or calibrations, which are carried out at another time, is not absolutely necessary in order to limit the duration of the system test immediately before processing or treatment, in which a patient is already docked, to an acceptable level.

[0024] Furthermore, the invention offers the advantage that the waiting time the patient may have to remain docked before the start of treatment can be reduced, thus minimizing the patient's discomfort caused by the wait. Additionally, the dose of medication required for the treatment may be reduced, as the time interval between medication administration and the start of treatment can be shortened.

[0025] Optionally, the control element is configured as a scanning device for beam deflection. Specifically, the control element can be configured as a laser beam scanner (also referred to as a scanning device), an actuator, an acousto-optic modulator (AOM), an electro-optic modulator, and / or an adaptive mirror, or at least comprise one of these elements. Optionally, the functional testing of the control element includes a test of the scanning device using at least one control element sensor, or may consist of one of these sensors. A negative result of the test or functional check can then indicate a fault, whereby the control element and / or the sensor may be the cause of the fault. To increase the reliability of fault detection in the control element, two or more redundant sensors can optionally be used for the functional testing of the control element.This offers the advantage that the correct functioning of the scanning device for beam deflection can be reliably checked before the start of treatment.

[0026] Optionally, the test includes controlling the scanning device such that it is set according to a scan pattern to guide a laser beam along a predetermined scan path, whereby the setting of the scanning device for the respective deflection of the laser beam by the scanning device can be determined by means of the at least one control element sensor. For the purposes of this invention, a scan pattern is a sequence of control data that can be supplied to the scanning device to generate a sequence of beam guidance configurations. The scan path, on the other hand, is a sequence of virtual focus positions that results from the sequence of the associated beam guidance configurations, i.e., from the scan pattern. In other words, the scan pattern is a sequence of settings for the scanning device that allows the focus to be moved along the scan path.A virtual focus, also known as a virtual focus position, is a theoretical position of a laser focus that can be assigned to a specific configuration of the beam path and, in particular, the scanning device. The number of virtual focus positions can be greater than the number of actual focus positions, since not every configuration of the scanning device necessarily results in an actual focus. An actual focus, also known as an actual focus position, is the position of a laser focus created by laser radiation passing through a specific configured beam path (optics) and, in particular, a specifically configured scanning device. A variable beam path configuration can ensure that every actual focus position can be achieved with at least one specific configuration of the scanning device.

[0027] Guiding the laser beam means that the laser beam is deflected by the scanning device in such a way that the virtual and / or real focus is guided along the predefined scan path. It is irrelevant whether a laser beam actually strikes and is deflected by the scanning device when it is adjusted, i.e., whether a real focus is created, or whether the scanning device is adjusted without a laser beam striking it, and thus only a virtual focus is deflected. In other words, the adjustments and checks of the scanning device can also be carried out in such a way that no laser beam is actually deflected by the scanning device, but rather the suitability of the scanning device for the desired deflection of the laser beam is merely verified. This can be done, for example, using suitable sensors on the scanning device.In other words, guiding the laser beam along a predetermined scan pattern corresponds to the controlled creation of a scan path, i.e., a change in the position of the possibly focused laser beam within the plane or volume in which the object to be processed is illuminated by the laser beam. Accordingly, two different types of functional tests can be used for the scanning device. The first type involves only checking the configuration of the beam guidance, i.e., the mechanical mirror positions and the associated virtual focus positions. The second type involves checking the actual focus positions, for example, by optically detecting and evaluating a confocal back reflection of the respective actual focus.

[0028] Optionally, the laser beam can also be guided in a direction parallel to the optical axis, for example, by changing the position of the focus along the beam direction, such as by changing the convergence angle of the laser beam and / or the position of the focusing element. This allows the laser beam or focus to be guided along a three-dimensional scan path. The resulting scan path of the scan pattern can be continuous or interrupted. The scan path can also have multiple segments and / or multiple points onto which the laser beam is applied and optionally focused along a predetermined scan path, i.e., in a predetermined sequence. In other words, the test scan pattern is optionally configured such that the associated scan path covers all focus positions intended for a predetermined laser processing operation by the laser processing system.The laser beam positions are included. Optionally, the predetermined scan pattern can be selected such that the scan pattern is representative of the entire usable value range of the scanning device.

[0029] This offers the advantage that the test is universally applicable and does not need to be individually created for each planned treatment. A scan pattern can also be optionally selected so that the required test duration is shorter than any intended treatment. Testing the scanning device offers the advantage of verifying its functionality in deflecting the laser beam along the path predetermined for the planned treatment. Focusing the laser beam is optional. Therefore, there can be applications in which the laser beam is focused and other applications in which it is not. If focusing occurs, the at least one focusing element can be positioned upstream of the scanning device according to some embodiments and downstream according to other optional embodiments.Optionally, when using femtosecond lasers, the laser beam is focused only after the scanning device, i.e., after deflection. Optionally, when using excimer lasers, the laser beam is focused before the scanning device and the convergent laser beam is then deflected.

[0030] Optionally, the scan pattern is configured such that the laser beam, within the scan path belonging to the scan pattern, at least partially detects a reference object characterizing the variable parameter, and the variable parameter can be determined from a resulting signal. This offers the advantage that the detection of the reference object characterizing the variable parameter can be combined with the testing of the control element and can be processed accordingly during the functional check or test. This is possible for reference objects located in an area accessible to the laser beam, i.e., in the area that can be detected by the laser beam deflected by the scanning device.

[0031] Optionally, the signal resulting from the laser beam's detection of the reference object includes a reflected portion of the laser beam, a scattered portion, and / or an emission signal excited by the laser beam. This signal is detectable by a reference object sensor. For example, the reference object can reflect and / or scatter a portion of the incident laser beam, making the reflected and / or scattered portion detectable by the reference object sensor. This can be used, for instance, to verify the actual focus position relative to a reference object. This can be achieved, for example, by interface detection, as described in WO 2008 / 040436 A1. Optionally, the laser beam is only emitted at points along the predetermined scan path.In such configurations of the scan pattern, the laser processing system emits laser radiation where the laser beam at least partially captures the reference object. This is not contradicted by the fact that the laser source of the laser processing system optionally emits laser radiation even when the laser processing system is not emitting a laser beam. This is because the laser beam can be blocked and / or deflected within the laser processing system, and thus, while emitted by the laser source, is not applied by the laser processing system to a patient or an object to be processed. This offers the advantage that the test or functional check can be performed even when the patient is already docked to the laser processing system or an object to be processed is already docked to the laser processing system, particularly by checking the virtual focus position(s).The functional testing of the control element can be carried out, at least partially, without an emitted laser beam, for example by providing appropriate sensors that can determine the exact positioning and / or deflection and / or displacement and / or orientation of the control element even without being exposed to a laser beam.

[0032] Optionally, during functional testing of the control element, the laser beam is emitted at a power level below a threshold that poses no risk to or damage to the eye. The threshold for eye damage is the laser energy level below which no change to the material or tissue occurs in relation to the specific application. The threshold for eye damage is a safety threshold of laser energy below which no damage to the eye occurs, and in particular, no collateral damage to other parts of the eye not being treated, such as the lens and / or retina.Limiting the power to one of these power thresholds, preferably the threshold for eye hazard, offers the advantage that the functional testing of the control element can utilize the laser beam at least partially, while applying the laser beam to a patient's eye and / or an object being processed is harmless due to the power being below the threshold. In particular, this offers the advantage that the laser beam can be used during the functional testing of the control element to detect a provided reference object that characterizes the variable parameter.

[0033] The variable parameter can optionally characterize a variable element of the laser processing system, such as a patient docking unit and, in particular, a contact lens, a part of the optical system that is subject to changes, or a laser scanner and its control system, which may be subject to drift. Optionally, the variable parameter can characterize a property of the laser processing system and, in particular, a property of an interchangeable contact lens of the laser processing system. This can be, in particular, a geometric property of the contact lens. The variable parameter may be variable due to contact lens-dependent deviations that occur, for example, within the scope of manufacturing tolerances, whereby the deviations may nevertheless be significant enough that their consideration appears necessary to achieve the desired precision in laser treatment or laser processing.The variable parameters of a contact lens can include, for example, its thickness and / or diameter and / or centering (i.e., its lateral offset relative to the optical axis), and / or its shape, particularly its radius of curvature, and / or other geometric variations of the contact lens or parts thereof. By identifying the variable parameter and determining its influence on the intended laser processing, inaccuracies and reductions in precision due to the variable parameter can be reduced or even completely avoided. Variable configurations of components of the laser processing system or the eye itself can serve as reference objects, as can markings and / or marker elements from which stored information can be read, such as a barcode or a color marker.The contact lens surfaces (which exhibit variations between individual contact lenses) can serve as a reference object, represented by their variable shape. During the laser scanner test, the laser beam or focus can be guided in such a way that the laser beam intersects the contact lens surface along the scan path. The reflected and / or scattered portion of the laser beam is then detected by a reference object sensor and received and evaluated by the control unit. The contact lens surface is an optical interface that serves as a reference surface for the patient's eye, which is docked to the contact lens surface. In this docked state, the eye assumes the shape of this interface.Therefore, precise knowledge of the location of this interface relative to the laser focus position can be crucial for accurate processing of the cornea or other parts of the eye. The correlation of the signals detected by the reference object and the corresponding scanner positions, laser beam positions, and focus positions then allows for the determination of the geometric properties of the contact lens and thus the variable parameter. For example, a method described in patent application WO 2008 / 040436 A1 can be used for this purpose. The scan pattern along which the laser beam is moved during the scanning process of the contact lens can comprise or consist of a spiral scan path. For example, the scan path can be similar to or identical with a focus trajectory for a flap incision. Alternatively or additionally, a scan can be performed below the apex of the spherical interface.In this process, a plane of the actual focus positions can intersect the spherical interface in a circle. In other words, a confocal signal is generated in the form of a circle whose center coincides with the vertex of the interface and whose diameter, via a spherical cap shape given the known radius of curvature of the interface, indicates the height of the vertex.

[0034] Optionally, the contact lens can have one or more markings that serve as reference objects and contain information about the contact lens, such as its type, shape, and / or spatial arrangement. For example, the information can provide details about a contact lens type, its angular orientation, a shape-describing parameter, and / or a serial number, for example, by means of a barcode. The markings can provide information about the variable parameter, particularly through their spatial positioning and / or orientation within and / or on the contact lens. Alternatively or additionally, one or more reference objects can be provided that do not provide information through their positioning and / or orientation, but rather through other properties.For example, such reference objects can be designed as markers whose properties can be detected by the reference object sensor when they are detected by the laser beam. For example, the markers can provide a luminescence signal with a predetermined wavelength, so that corresponding information can be extracted from this wavelength or color. For example, the contact lens size can be indicated by a corresponding luminescence color code.

[0035] The control signals for the laser scanner can be configured so that they correspond exactly to those of a treatment for the x and y scanners. The z scanner is controlled slightly differently from a treatment, ensuring that the contact lens surface is reliably cut by the focal trajectory. The laser radiation is active during the system test but is optionally attenuated to a safe level (laser class 1). Further parameters of the laser radiation can be controlled and / or monitored during the system test, just as in the actual treatment (e.g., pulse picking). Optionally, a confocal optic with a photodiode sensor serves as the reference object sensor for the scanning process. A portion of the incident laser beam can first be reflected back from the contact lens surface into the incident laser beam and then diverted from the main path via a polarizing beam splitter.The detected signal can then be used to determine the variable parameter and to optimize the control signals for the laser scanner in order to increase the accuracy of the treatment.

[0036] Optionally, the variable parameter relates to a property of the eye being treated with the laser processing system, in particular a changing spatial position of the eye relative to the laser processing system. Optionally, a surface in the eye that reflects and / or scatters part of the laser beam serves as the reference object. For example, the iris and / or the retina and / or the cornea, or parts thereof, can represent such a surface. This offers the advantage that, during the functional testing of the control element, the orientation and / or positioning of the eye docked to the laser processing system can be determined.

[0037] Optionally, the variable parameter relates to a variable property of a measuring unit of the scanning device, in particular a signal conversion unit, wherein at least a part of an optical element in the beam path of the laser processing system with a known geometry serves as the reference object. For example, the known surface of the optical element serving as the reference object, such as the surface of a lens in the beam path of the laser beam, can be scanned by the laser beam or, optionally, by the focus of the laser beam, and the shape of the surface determined by the measuring unit can be compared with the known, actual shape. Any deviation due to the variable parameter can then be used to derive information for optimizing control signals for the control element, such as for the laser scanner or the scanning device, in order to at least partially compensate for the deviation.A corresponding optimization procedure can also be applied to other variable elements, provided that these have an influence on the control of the laser scanner.

[0038] Optionally, the procedure also includes checking at least one additional component of the laser processing system from the following list: a shutter unit, a pulse picker unit, or an attenuator unit. This offers the advantage that one or more of these additional tests can be performed at least partially concurrently with the other tests and / or calibrations, thus further reducing the overall duration of a system test.

[0039] Optionally, the procedure also includes checking the laser source, which can be a pulsed laser source such as a femtosecond laser, particularly with regard to at least one of the following parameters: pulse energy, peak intensity, pulse frequency, and pulse duration. This offers the advantage that checking the laser source can also be carried out at least partially simultaneously with tests and / or calibrations of the laser processing system, thus further reducing the overall duration of a system test.

[0040] Optionally, the procedure also includes a check of one or more safety devices of the laser processing system. This can optionally be performed after the variable parameter has been determined, but at least partially concurrently with the functional test of the control element. For this purpose, a shutter can optionally be placed in the laser beam path to prevent the laser beam from escaping. This allows the functionality of the shutter to be verified. Optionally, the elapsed time between the activation command to trigger the shutter and the complete blocking of the laser beam can be determined and compared with a reference value. A photodiode, for example, located behind the shutter, can be used as a sensor. Alternatively or additionally, the shutter can be designed at least partially as a mirror, so that when closed it directs the laser beam onto a photodiode.Alternatively or additionally, the photodiode can be designed as a non-linear sensor in order to also determine the peak intensity of the laser pulses.

[0041] Optionally, the results of a target / actual comparison of the scanner positions obtained during the system test are compared with predefined tolerance conditions. Adherence to these predefined tolerances may be required for the laser processing system to be released for treatment and / or processing. Optionally, the properties of the variable element determined during the system test are also compared with predefined tolerance conditions. Again, adherence to these predefined tolerances may be required for the laser processing system to be released for treatment and / or processing.

[0042] The properties of the variable element determined during the system test are optionally used to adapt the scanner control signals generated for subsequent laser treatment to these properties (e.g., adapting the scan pattern to the position and / or shape of the contact lens). Optionally, the scanner movements during the system test completely cover the treatment area that is possible or expected for the scanner. Optionally, the scanner movements during the system test include at least parts of the possible scan area that are representative of scanner movements that typically occur during treatment. Alternatively or additionally, the scanner movements during the system test include parts of the possible scan area that are representative of movements where the highest probability of malfunction is expected during treatment.

[0043] Optionally, additional sensors can be integrated into the laser processing system for system testing. According to optional configurations, it is possible to perform the system test while the laser optics are swiveled out of the treatment position. Depending on the configuration, this can lead to a transformation (e.g., rotation) of the function that connects the contact lens coordinate system to the scanner control signals. For example, if the system test determines the position of the contact lens front surface in order to adjust the scanner control signals for the subsequent treatment, the effect of the swiveling must be taken into account. A suitable sensor that measures the swiveling can be advantageous for this purpose.

[0044] Furthermore, one or more properties of one or more variable elements can optionally be measured. In the case of contact glass detection, for example, various contact glass surface parameters such as position, shape, boundaries, surface properties, and / or contamination can be determined.

[0045] Furthermore, an iterative determination of the properties of the changing element, i.e., the variable parameter, is optionally possible. Thus, the determination of variable parameters concerning the contact glass surface can include the following parts: Part 1: Measurement of the approximate position of the contact lens at three points. Part 2: Based on the results of Part 1, a more precise measurement of the shape is carried out along several lines.

[0046] The light reflected and / or scattered at a contact glass surface before reaching a contact glass detection unit, which serves as a reference object sensor, can, for example, follow the same path as the incident laser beam or a different path. For instance, confocal detection, as described in patent application WO 2009 / 146906 A2, can be used to detect the scattered and / or reflected portion of the laser beam. In the former case, a beam splitter can be used to separate the incident light from the reflected light. This beam splitter can optionally have a constant splitting ratio or utilize polarization effects. Furthermore, this beam splitter (and any associated elements such as wave plates) can optionally be removed from the beam path after system testing.Instead of attenuating the laser beam during the test, a beam trap behind the last relevant optical surface can optionally prevent the escape of intense laser radiation.

[0047] Optionally, further parameters relating to the contact glass can be recorded. Often, known properties are used as a positional reference. This allows the detection time or test duration to be kept short. For example, if the surface shape of the contact glass is known, three measuring points in space may be sufficient to determine the exact position of the contact glass surface.

[0048] The method and control unit are optionally also applicable to excimer lasers that do not produce a defined laser focus. This allows, for example, the correct positioning and / or size of a patient interface to be checked, and / or the scaling of a laser scanner's measuring unit. In this case, the conditions relating to the laser focus are eliminated and generally replaced by the (unfocused) laser beam. Detection of the reference object's position is then primarily possible laterally.

[0049] The laser source used during the system test does not necessarily have to be identical to the one used for the treatment, although this is the case in some optional embodiments.

[0050] The design of the detection unit for the reference object sensor can vary. For example, the reference object sensor can include a photodiode and / or a camera. In the case of a photodiode, this can be an optional component of confocal observation for contact glass detection. A camera could also detect scattered light from laser-etched markings in a contact glass.

[0051] The features and embodiments mentioned above and explained below are not only to be regarded as disclosed in the combinations explicitly mentioned, but are also covered by the disclosure content in other technically meaningful combinations and embodiments.

[0052] Further details and advantages of the invention will now be explained in more detail with reference to the following examples and preferred embodiments and the figures.

[0053] They show: Figure 1 shows a laser processing system 100 according to an optional embodiment; Figure 2 shows an explanation of the interaction of several components for a system test according to an optional embodiment.

[0054] For the sake of simplicity, identical or similar elements in the various embodiments are designated with the same reference numerals in the following figures.

[0055] Figure 1Figure 100 shows a schematic representation of a laser processing system 100 according to an optional embodiment, which is designed as a device for refractive surgery of an eye. The laser processing system 100 is thus designed as a treatment device and serves to perform refractive correction on a patient's eye 2 using a refractive surgery procedure with a laser beam. For this purpose, the device 100 includes a laser or laser source 3, which emits pulsed laser radiation. The pulse duration is, for example, in the femtosecond range, and the laser radiation acts on the cornea of ​​eye 2 to separate a lenticule from the surrounding cornea.

[0056] The laser beam or treatment beam 4 emitted by the laser source 3 along an optical axis A1 falls onto a beam splitter 5, which directs the laser beam 4 onto a control element 6, designed as a scanning device 6a. According to the illustrated embodiment, the scanning device 6a has two scan mirrors 7 and 8, which are rotatable about mutually orthogonal axes, so that the scanning device 6a deflects the treatment beam 4 two-dimensionally. An adjustable projection optic 9 focuses the treatment beam 4 onto or into the eye 2. The projection optic 9 has two lenses 10 and 11.

[0057] A contact lens 12 is positioned downstream of the lens 11 and is firmly connected to the lens 11, and thus to the laser processing system 100, via a holder H. The contact lens 12 rests against the cornea of ​​the eye 2. The optical combination of the contact lens 12 and the other optical components of the laser processing system 100 causes the treatment beam 4 to be focused at a focus 13 located in the cornea of ​​the eye 2.

[0058] The device 100 further comprises a control unit 14, which is specifically configured to control the scanning device 6a, the laser 3, and the projection optics 9. The control unit 14 is also configured to monitor the functionality of the device and, for this purpose, to perform a system test to verify the functionality of the laser processing system 100. For this purpose, the control unit 14 can subject elements of the laser processing system 100 to testing and / or calibration. In doing so, the control unit 14 can cause the elements of the laser processing system 100 to carry out predetermined processes, which are then monitored by suitable sensors and / or detectors.The measurement data used by the sensors and / or detectors are then fed back to the control unit 14 and can be used by it to check the functionality and for further control of the laser processing system 100.

[0059] Although only one control unit is shown in the embodiment depicted, according to other embodiments several control units can also be provided that perform the aforementioned tasks and / or other tasks.

[0060] The laser processing system 100 also includes a reference object sensor 17, which, according to the illustrated embodiment, serves to determine a variable parameter relating to the contact glass 12. The reference object sensor 17 is arranged in the area between the contact glass 12 and the lens 11 and is configured to detect parts of the incident laser beam reflected and / or scattered by the contact glass and to transmit the measurement results via a communication line 17a to the control unit 14 for further evaluation. According to other embodiments, the reference object sensor can also be arranged elsewhere. For example, the detector 15 can also serve as a confocal reference object sensor.A reference object 19 can, for example, be a marker within the contact glass, which backscatters and / or reflects a portion of the incident laser beam. Information about the variable parameter, such as the geometric dimensions and / or orientation of the contact glass 12, can then be determined from the backscattered and / or reflected portion of the laser beam. Alternatively or additionally, when detected by the laser beam, the reference object 19 can emit a luminescence signal, which can be detected by the same reference object sensor 17. The control unit 14 can then derive further information from this signal, such as the size of the contact glass. This can be done, for example, by evaluating the wavelength or color of the luminescence signal. The luminescence can be based on fluorescence and / or phosphorescence.

[0061] The control unit 14 further reads a detector 15 of the laser processing system 100, which detects radiation backscattered and / or reflected from the cornea, passing through the contact lens 12 and through the beam splitter 5 as backscatter 16. For this purpose, a confocal imaging of the backscattered backscatter 16 onto the detector 15 can be performed. According to an optional embodiment, this detector can also serve as a reference object sensor and determine a variable parameter relating to the eye 2. For example, information about the positioning and / or orientation of the eye 2 can be determined by the detector as a (further) variable parameter and transmitted to the control unit 14. The reference object 19 can be formed by a property of the cornea or from the interior of the eye 2.

[0062] A method for performing a system test of the laser processing system 100 according to an optional embodiment is described below using the following as an example. Figure 2 explained. Figure 2 The schematic representation shows the interaction of the laser source 3, the scanning device 6a, the reference object 19, the reference object sensor 17 and the control unit 14.

[0063] For example, a variable parameter characterizing the contact lens 12 is to be determined. The variable parameter to be determined within the system test is the precise position of the anterior corneal surface, which is influenced by the exact geometric dimensions of the contact lens 12. Due to variations between different eyes and the resulting changes in the variable parameter, precise determination of this parameter is advantageous for achieving a high degree of precision. Particularly when using non-aplaning contact lenses, the differences between individual eyes can significantly affect the achievable level of precision. However, due to manufacturing tolerances, even with aplaning contact lenses, slight variations can occur between otherwise identical contact lenses 12, which should be taken into account to achieve a high degree of precision.

[0064] To minimize the duration of the system test, the functional test of the scanning device 6, which serves as the control element, and the determination of the variable parameter (precise position of the anterior cornea; determined by a contact lens) are performed at least partially simultaneously, according to the described embodiment. The functional test of the scanning device 6a involves moving mirrors along a scan pattern to the positions required for the planned treatment and, optionally, to additional positions. For this purpose, the mirrors of the scanning device 6a can, for example, be equipped with suitable angle sensors. The measurement data from the angle sensors are transmitted to the control unit.Simultaneously, at the points in time when the scanning device is positioned along the scan path during functional testing such that a laser beam passing through it falls onto the reference object 19 located in the contact glass, the laser beam is released, allowing the reference object 19 to be detected by the laser beam. It should be noted that this occurs during the ongoing functional testing of the scanning device, meaning both processes are carried out simultaneously. The reference object 19 detected by the laser beam sends a signal to the reference object sensor 17. This signal can, for example, contain a reflected and / or scattered portion of the laser beam and / or a luminescence signal excited by the laser beam. The measurement data acquired by the reference object sensor 17 are then transmitted to the control unit 14 and evaluated by it.

[0065] The functionality thus includes, firstly, controlling the laser source 3 and the scanning device 6a for performing the system test, and secondly, at least partially simultaneously receiving measurement data acquired by the sensors of the scanning device (e.g., angle sensors of the mirrors) during the functional test and transmitted to the control unit, as well as receiving measurement data transmitted by the reference object sensor 17. The control unit 14 must therefore be designed to perform these multiple tasks simultaneously. In particular, the control unit 14 must be equipped with sufficient processor power and memory capacity. The control unit 14 can then perform a target-actual comparison based on the received and evaluated measurement data and compare the result with predetermined tolerance values.If the result of the system test determined by control unit 14 indicates that the laser processing system 100 is functioning correctly, the control unit can enable the laser processing system for treatment. If the result of the system test indicates that the laser processing system is not functioning properly, control unit 14 can prevent the treatment from being carried out and / or issue a corresponding warning to the user. Reference symbol list

[0066] 2 Eye 3 Laser 4 Laser beam 5 Beam splitter 6 Control element 6a Scan device 7 Scan mirror 8 Scan mirror 9 Projection optics 10 Lens 11 Lens 12 Contact glass 13 Focus 14 Control unit 15 Detector 16 Backlight 17 Reference object sensor 17a Communication line 19 Reference object 100 laser processing systems A1 optical axis

Claims

1. Method for carrying out a system test of a laser processing system (100), the method comprising the steps of: - carrying out a functional test of a control element (6) of the laser processing system (100), wherein the control element (6) is designed as a scanning device (6a) for beam deflection and the functional test of the control element (6) comprises or consists of a test of the scanning device (6a) by means of at least one control element sensor and the test comprises controlling the scanning device (6a) in such a way that the scanning device (6a) is set in accordance with a scanning pattern for guiding a laser beam (4) along a predetermined scanning path, wherein a respective setting of the scanning device (6a) for deflecting the laser beam (4) by way of the scanning device (6a) is ascertainable by means of the at least one control element sensor; and - ascertaining a variable parameter and determining an influence of the ascertained variable parameter on intended carrying out of laser processing by means of the laser processing system (100); characterized in that: - carrying out the functional test of the control element (6) and ascertaining the variable parameter overlap one another at least partly in time; and - the scanning pattern is designed in such a way that the laser beam (4) in the region of the scanning path at least partly detects a reference object (19) characterizing the variable parameter, and the variable parameter is ascertainable on the basis of a signal resulting therefrom.

2. Method according to Claim 1, wherein the scanning pattern is designed in such a way that the resulting scanning path comprises at least some of those focus positions which are provided for predetermined laser processing by way of the laser processing system (100).

3. Method according to Claim 1 or 2, wherein the signal resulting from the detection of the reference object (19) by the laser beam (14) comprises a reflected portion of the laser beam (4) and / or a scattered portion of the laser beam (4) and / or an emission signal excited by the laser beam (4), and wherein the signal is detectable by a reference object sensor (17).

4. Method according to any of the preceding claims, wherein the laser beam (4) is emitted only at such locations of the predetermined scanning path through the laser processing system (100) at which the laser beam (4) at least partly detects the reference object (19).

5. Method according to any of the preceding claims, wherein the laser beam (4) is emitted during the functional test of the control element (6) with a power which is below a power threshold for endangerment and / or processing of an eye (2).

6. Method according to any of the preceding claims, wherein the variable parameter concerns a property of the laser processing system (100).

7. Method according to Claim 6, wherein the variable parameter characterizes a geometric property of an exchangeable contact glass (12) of the laser processing system (100).

8. Method according to any of Claims 1 to 5, wherein the variable parameter concerns a property of an eye (2) to be treated by means of the laser processing system (100).

9. Method according to Claim 8, wherein the variable parameter concerns a variable spatial position of the eye (2) relative to the laser processing system (100), and wherein a surface in the eye (2) which reflects and / or scatters a part of the laser beam (14) serves as reference object (19).

10. Method according to any of Claims 1 to 5, wherein the variable parameter concerns a variable property of a measuring unit of the scanning device (6a), in particular of a signal conversion unit, and wherein at least one part of an optical element in the beam path of the laser processing system (100) with previously known geometry serves as reference object (19).

11. Method according to any of the preceding claims, furthermore comprising checking at least one further component of the laser processing system (100) from the following list: a shutter unit, a pulse picker unit, an attenuator unit.

12. Method according to any of the preceding claims, furthermore comprising checking the laser source (3) with regard to at least one parameter of the laser source (3).

13. Method according to Claim 12, wherein the laser source (3) is designed as a pulsed laser source and the pulsed laser source (3) is checked with regard to at least one of the following parameters: pulse energy, peak intensity, pulse frequency, and pulse duration.

14. Control unit (14) for a laser processing system (100), wherein the control unit (14) is configured, in the context of a system test of the laser processing system (100), - to carry out a functional test of the control element (6) of the laser processing system (100), wherein the control element (6) is designed as a scanning device (6a) for beam deflection and the functional test of the control element (6) comprises or consists of a test of the scanning device (6a) by means of at least one control element sensor and the test comprises controlling the scanning device (6a) in such a way that the scanning device (6a) is set in accordance with a scanning pattern for guiding a laser beam (4) along a predetermined scanning path, wherein a respective setting of the scanning device (6a) for deflecting the laser beam (4) by way of the scanning device (6a) is ascertainable by means of the at least one control element sensor; and - to ascertain a variable parameter and to ascertain an influence of the variable parameter on intended carrying out of laser processing by means of the laser processing system (100); characterized in that - the control unit (14) is furthermore configured to carry out the functional test of the control element (6) and the ascertaining of the variable parameter in a manner overlapping one another at least partly in time and to receive and / or to evaluate resultant measurement data and / or measurement results at least partly simultaneously; and - the scanning pattern is designed in such a way that the laser beam (4) in the region of the scanning path at least partly detects a reference object (19) characterizing the variable parameter, and the variable parameter is ascertainable on the basis of a signal resulting therefrom.

15. Laser processing system (100), comprising a control unit (14) according to Claim 14, wherein the laser processing system (100) is optionally designed as an apparatus for refractive surgery on an eye (2).