DE102014014565A1 - Producing cuts in a transparent material by means of optical radiation - Google Patents

Abstract

A method for producing cuts in a transparent material by means of optical radiation, wherein the optical radiation is focused in the material on a focus and the focus is moved along a trajectory, viewed perpendicular to a main direction of arrival of the radiation successively traversed trajectories are not on top of each other.

Description

The invention relates to a method for producing cuts in a transparent material by means of optical radiation, wherein the optical radiation is focused in the material on a focus and the focus is shifted along a trajectory.

The invention further relates to a method for generating control data for a laser device which generates sections in a transparent material by focusing optical radiation, wherein the control data provide a trajectory for a shift of a focus to the optical radiation in the material.

Finally, the invention relates to a processing device for producing cuts in a transparent material, wherein the processing device has a laser device, which is designed to produce cuts in a transparent material by focusing optical radiation, and a control device connected to the laser device which controls the laser device so that the laser device shifts a focus on optical radiation in the material along a trajectory.

Such methods or processing devices are known in the art. Particularly in the field of ophthalmology, such procedures and processing devices are used for interventions with which a defective vision is corrected. The cuts can be used, for example, to modify the cornea so that a defective vision is resolved. For example, methods are known in which a volume of the cornea is isolated and removed in order to modify the curvature and thus the imaging properties of the cornea for the correction of ametropia.

The generation of sections on the eye is also needed in cataract surgery. This operation removes a clouded eye lens. For this distance, it is beneficial to first slice the lens in the lens bag so that it can be removed by a surgically created small lateral access.

In these applications, as with other applications, optical radiation acts inside the material, such as the tissue that is transparent to the optical radiation. Usually, non-linear processes are used, which involve focusing machining radiation, usually pulsed laser radiation, into the material, ie. H. below the surface of the material. The generation of a cut surface happens then by the fact that the position of the focus is shifted in the material. In the understanding that this description is based on, the shift of the focus does not necessarily mean that radiation is also emitted into the focus at this point in time. In particular, when using pulsed laser radiation, the focus is continuously shifted and it will be delivered only at certain times during the focus shift laser radiation pulses. The corresponding optics or devices to focus shifts still work continuously, which is why the term "focus shift" here also the corresponding displacement of the point is understood, would be focused on the optical radiation, even if such radiation is not currently issued, for. B. between two laser pulses.

The high focusing of the laser radiation, d. H. a geometrically highly limited focus is of great importance for non-linear effects, since only then can the required power densities in the material be achieved. This applies both to non-linear processes in which a single focus already has an interaction, as well as to processes in which several laser radiation pulses emitted in succession interact to achieve a material-separating effect. In this regard, approaches are also known in which laser radiation pulses are emitted at a plurality of overlapping focal points and only in the overlap region does the interaction of the plurality of laser radiation pulses lead to material separation.

The required precise focusing of the laser radiation is understandably affected by the material through which the laser radiation is guided. Since, as already mentioned, the focus lies within the material when cutting surfaces are to be produced in the material, it is clear that cut surfaces with this principle can usually only be constructed in one direction opposite to the main direction of incidence of the laser radiation, ie from posterior to eye application to the anterior. Otherwise, material components in which material has already been separated, ie the cut surface is already partially built up, would disturb the passage of the laser radiation and thus the desired precise focusing. In other words, you have to cut based on the direction of incidence of the optical radiation deeper areas of the cut surface before higher lying areas of the cut surface can be generated.

Another problem which arises in the creation of cut surfaces by guiding a focus along a trajectory is the speed of the cut surface generation. The focus is usually deflected by means of a scanning device. Decelerating, repositioning or accelerating the scanning device can significantly increase the cutting edge production. In eye applications, this is not only troublesome for a patient, as the surgical procedure takes longer, with increasing time required for the Schnittflächenerzeugung also increases the cost, which must be taken to prevent unwanted eye movements.

This problem is particularly great when a sectioning of transparent material is to take place, ie intersecting cut surfaces are required. Due to the points of intersection and the fact that the cut surfaces must be built up in layers against the direction of incidence of the radiation, the braking, repositioning and acceleration of the scanning device leads to a very large extension of the cut surface generation.

Although in the prior art approaches are known to perform the deflection as continuously as possible, so as to dispense with braking and acceleration operations of the deflection as possible (see. DE 102008027358 A1 ), but these approaches are limited to very specific cutting geometries.

When creating cuts in the cornea or the lens, the formation of gas bubbles is unavoidable. The more complex the patterns are, the greater the danger that the gas bubbles will have negative effects and z. B. can lead to a capsule rupture. As time efficient, the in DE102011085047A1 proposed generation of cuts on trajectories of periodically intersecting Lissajous figures. However, in the sections routed from bottom to top on periodic paths, there is still the danger that gas bubbles will lead to negative effects due to the concentrated symmetrical pattern.

The invention is therefore based on the object, the method or the processing device of the type mentioned in such a way that when creating intersecting cut surfaces, a high production rate can be achieved and this leads to a better result than in the prior art.

This object is achieved according to the invention by a method for generating sections in a transparent material by means of optical radiation, wherein the optical radiation is focused in the material on a focus and the focus is moved along a trajectory, being perpendicular to a main direction of arrival of the radiation as Trajectory is a harmonic curve is used and wherein adjacent trajectories in the main incident direction of the radiation are not superimposed.

The object is likewise achieved according to the invention with a method for generating control data for a laser device which generates sections in a transparent material by focusing optical radiation, the control data defining a trajectory for shifting a focus of the optical radiation in the material, the control data thus that a harmonic curve is used perpendicular to a main direction of incidence of the radiation and that adjacent trajectories in the main direction of arrival of the radiation are not superimposed.

The object is also achieved according to the invention with a processing device for producing cuts in a transparent material, wherein the processing device has a laser device which is designed to produce cuts in a transparent material by focusing optical radiation and has a control device connected to the laser device which controls the laser device such that the laser device shifts a focus of the optical radiation in the material along a trajectory, wherein the control device controls the laser device such that a harmonic curve is used perpendicular to a main direction of incidence of the radiation and adjacent trajectories in the main direction of incidence Radiation does not lie on top of each other.

wobei γ →(t) die Bahnkurve, γ_x(t) die Schwingung in x-Richtung, γ_y(t) die Schwingung in y-Richtung und t die Zeit ist.It is therefore used as a basic figure, a trajectory, which forms perpendicular to the main incident direction of the radiation, a closed planar trajectory, which is generated by superposition of at least one harmonic oscillation in two orthogonal directions in space. Such a basic figure has as a general formula:

in which γ → (t) the trajectory, γ _x (t) is the oscillation in the x-direction, γ _y (t) is the oscillation in the y-direction and t is the time.

mit

als Drehwinkel, z₀ als Startwert für die z-Achse.This trajectory has the advantage that the deflection device, which is usually realized as a biaxial scanner, continues to operate in accordance with harmonic oscillations. Conventional scanning mirrors achieve their maximum operating speed precisely in this harmonic oscillation mode. Thus, the focus can be guided at maximum speed along the trajectory. To create the desired intersecting cut surfaces, an intersecting Trajectory used. In contrast to the prior art, the trajectories at different depths in the material are not exactly positioned one above the other. In order to realize this, the trajectories for different depths are not intermittent. Preferably, the non-periodicity of the successive execution of the basic figure is selected so that the basic figure rotates about its axis of symmetry after each execution. The general formula is

With

as angle of rotation, z ₀ as starting value for the z-axis.

als Verschiebewerte.Simultaneously with the rotation, the z-axis is preferably moved slowly through, so that after the basic figure, the next basic figure is offset both in the z-direction and rotated by a certain angle. This rotation of the cuts ensures that the gas bubbles are not all arranged one above the other and thus lead to a local overpressure. Preferably, the total rotation from the lower incision (beginning above the posterior capsule) to the upper incision (ending below the anterior capsule) is between 20 ° and 135 °, and more preferably 45 °, 60 °, 90 ° or 120 °. This rotation angle ensures on the one hand a sufficient distribution of the gas bubbles over the surface and on the other hand ensures a good removability of the resulting lens fragments. The angle around which the basic figure is rotated after each step in the direction of the z-axis is thus the angle of the total rotation divided by the number of z-steps. If the selected total rotation angle coincides with the count of the rotational symmetry of the basic figure at the end of the series execution, all the sub-sections forming the basic figure along the z-scan cover surface pieces which form a clearly recognizable contiguous surface in the projection (viewing direction of the surgeon) due to the blistering. The surgeon recognizes both the surgical progress, as well as the photodisruptive effect in the various tissue layers. With a count of 4 thus exactly 4 sectors of 90 ° are created and with a count of 6 6 sectors of 60 ° are created. Alternatively, a slow shift of the pattern in the x- or y-direction is possible. This can be done by slowly moving the scanners in x-direction or y-direction. Here is the general formula:

as shift values.

als x- und y-Komponente der Streckung. Dies ermöglicht die radialen Abmessungen der Grundfigur den Schnittanforderungen der aktuellen Ebene (z-Position) anzupassen. Ohne eine solche Anpassung müsste man Teile der Grundfigur im unerwünschten Gebiet ausblenden bzw. auf vollständiges Schneiden bis zum Rand in anderen Ebenen verzichten. Alternativ ist auch eine Veränderung der relativen Phase der Lage der Laserimpulse entlang der Grundfigur möglich. Allgemeine ergibt sich hier die Bahnkurve zu:

als relative Phasenänderung. Damit kann die Position der Laserimpulse zwischen zwei Grundfiguren z. B. so verändert werden, dass die Spots der einen Grundfigur jeweils genau in den Lücken der anderen liegen. Auf diese Weise wird die geometrische Nähe der Gasblasen auch benachbarter Hintereinanderausführungen der Grundfigur reduziert. Es liegt auch im Rahmen der Erfindung, die Grundfiguren durch gleichzeitiges Verschiebung, Rotieren und Strecken ineinander zu überführen indem die Scanner in x-Richtung und/oder y-Richtung in Amplitude und Phasenlage der beteiligten Frequenzkomponenten geeignet angesteuert werden.Preferably, the scanner motion on the lower cut starts off-axis and moves up so that the scanners cross the axis approximately in the center of the lens and continue to move upward in that direction. Alternatively, a slow extension or compression relative to the symmetry axis of the basic figure is possible. Here the trajectory is defined by:

as the x and y component of the stretch. This allows the radial dimensions of the basic figure to match the cutting requirements of the current plane (z-position). Without such an adaptation, you would have to hide parts of the basic figure in the undesirable area or dispense with complete cutting to the edge in other levels. Alternatively, a change in the relative phase of the position of the laser pulses along the basic figure is possible. General results here the trajectory to:

as relative phase change. Thus, the position of the laser pulses between two basic figures z. B. are changed so that the spots of a basic figure each lie exactly in the gaps of the other. In this way, the geometric proximity of the gas bubbles is also reduced adjacent successive embodiments of the basic figure. It is also within the scope of the invention, the basic figures by simultaneous displacement, rotation and stretching into each other by the scanner in the x-direction and / or y-direction in amplitude and phase of the participating frequency components are suitably controlled.

Furthermore, it is within the scope of the invention that, with a constant z-value, a rotation of the basic figure about its own axis is carried out in such a way that complete separation takes place in this plane (360 ° / index of symmetry). Preferably, this plane is located in the middle of the lens. As the individual webs are closer together in the center than at the edge of the lens, this procedure sets more spots in the center of the lens than at the edge. Therefore, with this approach, lenses, where as usual the center is harder, cut better. It is also within the scope of the invention to reduce the number of webs to such an extent that only in the center a complete separation takes place and in the edge region the plane is virtually only perforated. The number of selected webs must only be so great that easy removal of the lens material is ensured during the subsequent removal of the lens of the eye. The number of webs is preferably selected depending on the hardness of the lens. For example, fewer webs can be selected for soft lenses than for hard lenses. This ensures that the time required for each level is low. Alternatively, laser pulses could also be placed only in the interior of the lens. In addition, it is also possible to use completely separating basic figures in more than one plane and to produce in this way transverse to the optical axis several cut surfaces.

In all the variants according to the invention, trajectories worn at different depths are staggered relative to one another and the desired side cut surfaces are established, which will generally be oblique to the main incident direction of the radiation.

The trajectories can also be made larger than the area in which the cut surfaces are to be formed in the material. In the areas in which the trajectories extend beyond this range, the optical radiation is preferably switched off or deactivated with regard to its material-separating effect. This can be done for example by a deliberate defocusing, change of spectral parameters, attenuation of the pulse energy, extension of the pulse duration, etc. The rendering harmless of laser radiation pulses is already known in the prior art in another context.

For this purpose, it is favorable if an interface area is defined, the trajectories are made larger than the interface area and the optical radiation is switched off or modified on sections of the trajectories which are outside the interface area, so that it does not create sections in the transparent material. Similarly, in the processing apparatus, the control means controls the laser device in areas where the trajectories are outside a predetermined sectional area, so that the optical radiation is turned off or modified so as not to produce cuts in the transparent material.

This results after the complete execution of the cuts in general a crooked lattice structure which, however, has no negative influence on the actual meaning of the cuts, namely the division of the lens tissue into removable pieces.

The processing device preferably has a scanner device which has two scanning mirrors deflecting mutually crossed axes and a focus shifter displacing the focus perpendicular thereto and along the main direction of arrival, wherein the control device controls the focus shifter so that the focus position changes after passing through the basic figure a distance is shifted against the main direction of arrival, which causes a coherent material separation of the successive passes through the displaced, twisted, compressed or stretched basic figure.

It is understood that the features mentioned above and those yet to be explained below can be used not only in the specified combinations but also in other combinations or alone, without departing from the scope of the present invention. The description of method features for material separation or for generating control data likewise relates equally to a corresponding embodiment of the control device which controls the processing device. Conversely, features that are described with regard to the processing device, in particular its control device, equally relevant to the corresponding method for material processing or for generating control data.

The control data generation can be carried out separately, ie independently of the processing device. Of course, it requires appropriate knowledge of the processing device for which the control data is provided.

The invention will be explained in more detail for example with reference to the accompanying drawings, which also disclose characteristics essential to the invention. Show it:

1 a schematic representation of a treatment device for ophthalmological procedures, in particular for the correction of ametropia,

2 a schematic representation of the structure of the treatment device of 1 .

3 a schematic diagram for introducing pulsed laser radiation into the eye with the treatment device of 1 .

4 a schematic representation to illustrate a grid of cut surfaces, with the treatment device of 1 should be generated

5 a schematic representation to illustrate the generation of the schematically represented sectional area of 4 .

6 a representation similar to the 5 but with a boundary of cut surfaces on a working area and

7 a further illustration to illustrate the production of the schematically represented sectional area of 4 for a larger z-range.

1 shows a treatment device 1 for eye surgery. This can z. B an ophthalmological procedure are carried out, which corresponds to the in EP 1 159 986 A2 respectively. US 5,549,632 is similar. The treatment device 1 generated by means of treatment laser radiation 2 a material separation in transparent material. This material separation can, for. B. be a Schnittflächenerzeugung, in particular, the treatment device for ametropia correction, a change in an eye 3 a patient 4 cause. Defective vision may include hyperopia, myopia, presbyopia, astigmatism, mixed astigmatism (astigmatism with hyperopia in one direction and myopia in a direction perpendicular thereto), aspheric aberrations and higher order aberrations. The material separation may be used in the field of ophthalmology but also on other tissues of the eye, z. B. for sectioning the eye lens in cataract surgery. As far as subsequently reference is made to eye surgery, this is by way of example only and not to be understood as limiting.

The modules of the device 1 be controlled in the described embodiment of an integrated control unit, which, however, may of course be designed independently.

2 shows schematically the treatment device 1 , In this variant, it has at least three devices or modules. A laser device L outputs the laser beam 2 on the material, for. The eye 3 and adjusts the position of the focus in the material in three spatial directions x, y, z. The adjustment along the main incident direction of the optical radiation (z-axis) is referred to as z-axis adjustment, the x and y-axis adjustment is preferably perpendicular to the z-axis by scanner

The operation of the laser device L takes place fully automatically under the control of an integrated or separate control device C. The laser device L starts the deflection of the laser beam in response to a corresponding start signal 2 and thereby creates cut surfaces that are constructed in a manner to be described.

The controller C operates on control data either generated by or supplied to it. In the latter case, the in 2 is shown, the control data required for the operation of the control device C are previously supplied by a planning device P as a control data record on unspecified control lines. The determination or transmission of the control data takes place before the operation of the laser device L. Of course, the communication can also be wireless. Alternatively to a direct communication, it is also possible to arrange the planning unit P spatially separated from the laser unit L and to provide a corresponding data transmission channel.

In ophthalmology is preferred before use of the treatment device 1 the refractive error of the eye 3 measured with one or more measuring devices M. The measured values are then fed to the control device or the planning device P and form the basis for the control data generation. In particular, the position and / or extent of a region to be processed, in particular to be sectioned, can be measured.

The control device or the planning unit P generates the control data record from the measurement data that has been determined, for. B. for the eye to be treated. They are the planning unit P supplied via an interface S and come in the illustrated embodiment of a measuring device M, the patient's eye 4 measured before. Of course, the measuring device M in any way the corresponding measurement data to the planning device P or directly to the control device C transmit.

Preferably, the control data set is transmitted to the control device, and further preferably, an operation of the laser device L is blocked until a valid control data record is present at the laser device L. A valid control record may be a control record that is principally for use with the laser device L of the treatment device 1 suitable is. In addition, the validity can also be linked to the fact that further tests are passed, for example, if the tax record additionally contains information about the treatment device 1 , z. B. a device serial number, or the patient, for. As a patient identification number to match other information that has been read out, for example, at the treatment device or entered separately as soon as the patient is in the correct position for the operation of the laser device L.

The transmission of the measured data and / or the control data can be effected by means of memory chips (eg via USB or memory stick), magnetic memories (eg floppy disks), or other data carriers, by radio (eg WLAN, UMTS, Bluetooth) or wired (eg USB, Firewire, RS232, CAN bus, Ethernet etc.). A direct radio or wire connection has the advantage that the use of incorrect measurement data is excluded with the greatest possible certainty. This applies in particular if the transfer of the patient from the measuring device M or the measuring devices to the laser device L takes place by means of a bearing device (not shown in the figure) which cooperates with the measuring device M or the laser device L such that the respective devices recognize if the patient 4 in the respective position for measuring or introducing the laser radiation 2 is. With a transfer of the patient 4 from the measuring device M to the laser device L can at the same time also the transmission of measurement and refractive error data to the treatment device 1 respectively.

It is preferably ensured by suitable means that the control device or the planning device P is always the one to the patient 4 generated tax record and an erroneous use of an incorrect tax record for a patient 4 is as good as impossible.

The laser radiation 2 is focused in the described embodiment as a pulsed laser beam in the material, for. The eye 3 brought. The pulse duration generated by the laser device L is z. B. in the femtosecond range, and the laser radiation 2 acts by means of non-linear optical effects in the material, eg. As the eye lens or the cornea. The laser beam has z. B. 50 to 800 fs short laser pulses (preferably 100-400 fs) with a pulse repetition frequency between 10 kHz and 10 MHz. The type of material-separating effect that the treatment device 1 used with the laser radiation, but is not relevant to the following description, in particular, no pulsed laser radiation must be used. It is only essential that a focus of machining radiation 2 is shifted in the material along a trajectory.

The treatment device 1 forms a cut surface in the material whose shape depends on the pattern with which the laser pulse foci are arranged in the tissue. The pattern in turn depends on the trajectory along which the focus is shifted. It specifies target points for the focal position at which one or more laser pulses are emitted, and ultimately defines the shape and position of the cut surface.

A possible mode of action of the laser beam 2 is in 3 indicated schematically. He is by means of an unspecified optics of the laser device L in the material, eg. B. the cornea 5 or lens of the eye. This creates a focus in the material 6 in that the laser energy density is so high that in combination with the pulse length a non-linear effect occurs. For example, each pulse of the pulsed laser radiation 2 at the respective place of focus 6 an optical breakthrough in the material, eg. In the cornea 5 or produce lens which in 3 exemplified schematically by a plasma bubble. As a result, due to this laser pulse material, for. B. tissue separated. When a plasma bubble is formed, the tissue layer separation comprises a larger area than the spot which the focus 6 the laser radiation 2 although the conditions for generating the breakthrough are only achieved in focus. In order for an optical breakthrough to be generated by each laser pulse, the energy density, ie the fluence of the laser radiation, must be above a certain, pulse length-dependent threshold value. This connection is the expert from the example of DE 695 00 997 T2 known.

Alternatively, a material-separating effect by the pulsed laser radiation can also be generated in that a plurality of laser radiation pulses are emitted in one area, wherein for several laser radiation pulses, the spots 6 may overlap or even be spaced. It then act together several laser radiation pulses to achieve a tissue-separating effect. For example, the treatment device 1 to use the principle that in the WO 2007/042190 A2 is described.

The treatment device 1 generated in the cornea 5 or in the lens of the eye 3 sectioning the tissue by making cut surfaces as lattice (this is of course not limited to ophthalmology). Through this in 4 schematically illustrated grid is transparent material 1a be sectioned so that it can be removed.

In the transparent material 1a becomes a grid of cut surfaces 10 . 11 . 12 generated by the focus 6 the laser radiation 2 extending along a propagation direction 3a spreads, within the transparent material 1a along a trajectory 6a is moved. The trajectory 6a is chosen so that it is based on a basic figure the cut surfaces 10 . 11 and 12 follows and this leaves.

When controlling the laser device L, the control device C ensures that the cut surfaces 10 . 11 and 12 through the trajectory 6a only contrary to the main propagation direction 3a of the laser beam 2 being constructed. Otherwise, the focus would be 6 by already existing material separations (for example, cut surfaces) in the incident light cone 4a disturbed. This problem arises quite fundamentally in material separation by focused optical radiation and is particularly large at intersections in the application described by way of example 5a the cut surfaces 10 . 11 and 12 ,

The sectional area shown in dashed lines 12 clarifies that the trajectory 6a must be arranged at different height levels to the mentioned laser focus interference in the incident light cone 4a to avoid. The trajectory 6a is therefore designed so that they first all cut surfaces 10 . 11 and 12 operates in the lowest altitude level, ie in that height level, based on the main direction of incidence 3a farthest from the laser device L is removed. Were using the trajectory 6a the cut lines of all cut surfaces 10 . 11 and 12 Processed in this height level, the same is done for the next height level, based on the main direction of incidence 3a closer to the laser device L. This is the basic figure of the trajectory 6a but now modified so that they are not in the main arrival direction 3a lies above each other with the just trajectory trajectory.

For a better overview are in 5 exemplarily the individual trajectories 20 . 21 . 22 pictured with which the cut surfaces 10 11 . 12 out 4 be generated. As can be clearly seen, the trajectories are 20 . 21 . 22 not over each other, but are at an angle 25 offset to each other since the departure of the basic figure of the exemplified z-plane 7 has been modified to the next z-plane as described above.

In order to avoid a time-consuming braking and repositioning or accelerating the focus deflection, the in 4 schematically illustrated grid of cut surfaces by moving the biaxial deflection of the laser device L on a planar trajectory 23 generated in 6 is shown. The basic figure needs only with respect to the x- / y-deflection, ie along the main direction of incidence 3a seen, be given. Only in this view, a closed, so periodic trajectory 6a be given.

There are thus two variants: First, the trajectory 6a lie in a height level. Then the z-position of the focus remains 6 constant, as long as the basic figure is traversed, and the trajectory 6a is also closed in three-dimensional space. The control data or the control by the control device thus cause a closed trajectory in each height level 23 on which the focus is guided. This is hereafter as a variant 1 designated. On the other hand, the z-adjustment can adjust the position of the focus, while the basic figure is traversed. This is hereafter as a variant 2 designated. Unless explicitly stated on the distinction of these two variants, the statements made here apply to both variants.

The basic figure is preferably formed by a superposition harmonic oscillations, so that the x- / y-deflection can be moved continuously with harmonic sine or cosine movements. A high working speed is the result.

In sections 23 the trajectory 6a which are located outside the area in which the intended intersections are to be created (also in 6 is an example of the cut surface 10 drawn), the laser beam is darkened, ie turned off or deactivated with respect to its processing effect. Only in sections 24 the trajectory 6a which are located within the area in which cut surfaces are to be located, the laser radiation is active and separates tissue. 6 shows the sections 23 the trajectory 6a dotted, in which the laser beam is darkened. The sections 24 the trajectory 6a , in which the radiation causes a material separation, are drawn through.

6 shows the distance 8th between the altitude levels in which each of the basic figure is traversed. In contrast to the prior art, the desired sectioning of the transparent material 1a reachable even if the basic figure is slightly stretched or compressed in each height level, its origin is slightly shifted or twisted as at the angle 25 is shown by way of example.

For creating the cut surfaces 10 . 11 and 12 can according to variant 1 the trajectory 6a in each altitude level, a full pass (or as mentioned in the general part of the description, several passes) through the basic figure.

To create the cut surfaces, it is according to variant 2 but also possible, the deflection along the main direction of arrival 3a while performing the basic figure. The control device or the control data generated by the planning unit cause a z-adjustment of the focus 6 either in a short section of track, which then makes a transition from between two levels of altitude variation 1 represents, or a continuous z-adjustment of the focus 6 , Based on the above-mentioned equations, in which the scan path repeats with a base frequency f ₀ , the focus moves with continuous z-adjustment 6 the z-coordinate of the focus 6 in the time period 1 / f ₀ by the desired distance 8th , the superposed trajectory sections should have.

7 shows once again the conditions in a 4-digit basic figure, which is rotated by a small angle after each pass. If this angle is determined so that after passing through the entire z-range just a quarter circle (because of the 4-Zähligkiet the basic figure) by trajectories 24 is filled, it is easy to see that the attending physician can easily follow the progress of the division of the eye lens. If the entire surface with trajectories 24 the treatment is completed and the intended area of the eye lens is divided into removable pieces.

The following features can additionally be realized:
It is also possible to darken the laser radiation on certain sections of the trajectory within an area in which cut surfaces lie if the course of the trajectory on the basic figure in such areas does not correspond to a desired cutting pattern.

The height levels do not have to be levels in the mathematical sense. In particular, in the case of curvature of the field and / or processing of curved material, the height planes may be curved 2D males.

When driving scanners, one can determine and account for the amplitude attenuation and phase delay of the x / y deflectors by providing appropriate amplitude and phase control of the deflection drive at high frequencies.

The frequencies of the deflection on the basic figures can take into account the maximum distance of spots to be hit by successive laser pulses.

The pattern produced with the basic figure can of course be supplemented by further cutting elements, for example a cylinder jacket as an outer boundary of the machined volume range. To the through the cut surfaces 10 . 11 and 12 generated parts of the transparent material 1a also perpendicular to the propagation direction 3a In addition to sharing, even between individual height planes cut surfaces that are substantially perpendicular to the main direction of incidence 3a extend, are generated.

The cut surfaces produced by means of the basic figure can be used for the sectioning of eye tissue, for example the eye lens or the cornea of the eye. It is also possible to effect a targeted weakening of a material by the crossed cut surfaces. In the field of eye surgery, it may be z. B. to an intrastromal weakening of the cornea to influence the balance between intraocular pressure and corneal strength so that a desired change in shape of the corneal anterior surface is achieved.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102008027358 A1 [0011]
• DE 102011085047 A1 [0012]
• EP 1159986 A2 [0037]
• US 5549632 [0037]
• DE 69500997 T2 [0049]
• WO 2007/042190 A2 [0050]

Claims (15)

A method for producing cuts in a transparent material by means of optical radiation, wherein the optical radiation is focused in the material on a focus and the focus is moved along a trajectory, characterized in that a harmonic curve is used as seen perpendicular to a main incident direction of the radiation and wherein adjacent trajectories in the main direction of arrival of the radiation are not superimposed. A method for generating control data for a laser device which generates sections in a transparent material by focusing optical radiation, wherein the control data provide a trajectory for shifting a focus of the optical radiation in the material, characterized in that the control data are generated so that perpendicular is used to a main direction of arrival of the radiation, a harmonic curve is used and wherein adjacent trajectories in the main direction of arrival of the radiation are not superimposed. Method according to one of the preceding claims, characterized in that the focus is additionally displaced along the main direction of incidence of the radiation and against the main direction of incidence. Method according to one of the above claims, characterized in that adjacent trajectories are twisted against each other. Method according to one of the above claims, characterized in that adjacent trajectories are shifted from each other. Method according to one of the preceding claims, characterized in that adjacent trajectories are stretched against each other. Method according to one of the preceding claims, characterized in that adjacent trajectories are shifted in phase against each other. Method according to one of the preceding claims, characterized in that an interface area is defined, the trajectory is made larger than the interface area, and the optical radiation is switched off on sections of the trajectory that are switched off outside of the interface area or modified such that they do not intersect in the transparent material generated. Method according to one of the above claims, characterized in that the cuts are formed as an oblique lattice structure. A processing device for producing cuts in a transparent material, wherein the processing device comprises a laser device, which is adapted to produce cuts in a transparent material by focusing optical radiation, and a control device connected to the laser device, which controls the laser device such that the laser device shifts a focus of the optical radiation in the material along a trajectory, characterized in that the control device controls the laser device such that a harmonic curve is used perpendicular to a main incident direction of the radiation and adjacent trajectories in the main incident direction of the radiation are not superimposed. Machining apparatus according to claim 10, characterized in that the control device controls the laser device so that adjacent trajectories are rotated against each other and / or shifted from each other and / or stretched against each other and / or shifted from each other in one phase. Machining apparatus according to claim 10 or 11, characterized in that the control means, the laser device in areas where the trajectory is outside a predetermined Schnittflächenbereichs so controlled that the optical radiation is switched off or modified so that it does not produce cuts in the transparent material. Machining device according to claim 10, 11 or 12, characterized in that the control device controls the laser device so that the cuts are formed as a lattice structure. Machining device according to claim 13, characterized in that the control device between at least two height levels provides an intermediate plane lying parallel to the height levels and controls the laser device so that in the intermediate plane a continuous cut surface is formed. Machining device according to one of Claims 10 to 14, characterized in that the focus is shifted by means of a scanner device which has two scanning mirrors deflecting mutually crossed axes and a focus shifting device displacing the focus perpendicular thereto and along the main direction of arrival, the control device comprising Focusing device controls so that after a pass through the trajectory, the focus position is shifted by a distance against the main direction of arrival, which is a contiguous Material separation of the successive passes through the non-superimposed trajectories causes.

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