Device and method for laser-radiating a workpiece blank for the production of a workpiece surface

Abstract

The present disclosure relates to a device (1) for laser-radiating a workpiece blank (3) for the production of a workpiece surface with a dimensional accuracy tolerance of below 5 µm, the device (1) comprising: - a rotary system (5) which is configured to clamp a workpiece blank (3) and rotate same at an adjustable rotating speed (ω) about a rotational axis (C), - a laser system (7) which is configured to direct a laser beam (9), pulsed at an adjustable laser pulse rate (f), onto or into a workpiece blank (3) rotated by means of the rotary system (5) and to focus said laser beam such that a laser focus (17) lies at a changeable radial distance (r) to the rotational axis (C) on or in the workpiece blank (3), - a control system (23) which is configured to control the laser focus (17) by changing the radial distance (r) of the laser focus (17) along a programmable radiation profile (21), wherein the control system (23) is further configured to adapt the laser pulse rate (f) of the laser system (7) and the rotational speed (ω) of the rotary system (5) depending on the radial distance (r) of the laser focus (17), wherein in a first range (A) of radial distances (r), the laser pulse rate (f) of the laser system (7) is adapted to the radial distance (r) of the laser focus (17) at preferably constant rotational speed (ω) of the rotary system (5) and in at least one second range (B, C, D, E) of radial distances (r), the rotational speed (ω) of the rotary system (5) is adapted to the radial distance (r) of the laser focus (17) at a preferably constant laser pulse rate (f) of the laser system (7).

Description

[0001] Applicant: InnoLite GmbH Title: Device and method for laser irradiation of a workpiece blank for producing a workpiece surface Our reference: INNP 3746 WO Description

[0001] The present disclosure relates to a device and a method for laser irradiation of a workpiece blank for producing a workpiece surface, as well as workpiece surfaces produced thereby. The workpiece surfaces should have a dimensional accuracy tolerance of less than 5 µm.

[0002] A workpiece blank can be processed in various ways using laser radiation in order to produce a workpiece surface of very high quality with high precision. On the one hand, a laser can be used to directly remove the material of the workpiece blank by means of laser ablation or laser evaporation. On the other hand, a laser can be used to expose the material of the workpiece blank during selective laser etching (SLE) in order to then chemically etch out the exposed areas. The present invention relates to laser irradiation 15 for laser ablation or laser evaporation as well as for SLE. The workpiece blank can in particular be a glass or glass-ceramic blank in order to produce a glass or glass-ceramic optic with an optically effective workpiece surface.Alternatively, the workpiece blank can be a wafer from semiconductor technology, a ceramic, a hard metal, or another material with a hard workpiece surface. Patent Attorneys Hemmer Lindfeld Frese INNP 3746 WO, 11 / 06 / 2024.

[0003] Laser ablation, or laser vaporization, is a well-known, single-step process for subtractive material processing. Ultrashort pulsed laser radiation is focused into or onto the volume of a workpiece. The pulse duration is in the range of a few femtoseconds or picoseconds. Due to the high intensity of the laser radiation in the focus area, a very rapid and locally limited temperature increase occurs there. Due to the relatively high local energy input density, the material of the workpiece is vaporized at the point of the laser focus.

[0004] SLE, on the other hand, is a well-known two-stage process for subtractive material processing. In the first stage, ultrashort pulsed laser radiation is focused into the volume of a workpiece transparent to the laser wavelength. The pulse duration is in the range of a few femtoseconds or picoseconds. Due to the high intensity of the laser radiation in the focus area, the laser energy is absorbed there due to multiphoton absorption. Due to the relatively high local energy input density, the chemical properties of the material at the point of the laser focus are modified, and the etching rate at the areas of the material exposed to the laser focus is increased by a factor of 20 compared to the non-exposed part of the material, for example, in the range of 100 to 1,000.Due to the selectively increased etching rate of the laser-exposed material, it can be preferentially removed from the exposed areas in a second step using a chemical etching process. The ratio of the etching rates between the laser-exposed and the non-exposed area is referred to as 25 selectivity. Acids or alkalis such as hydrofluoric acid (HF) or potassium hydroxide (KOH) are used as etching agents to remove the laser-exposed areas. Due to the possibility of performing laser processing without contact within the volume of a workpiece in the case of transparent materials of the workpiece blank, complex geometries with internal structures, such as microchannels, can be realized using the 30 SLE process. Patent Attorneys Hemmer Lindfeld Frese INNP 3746 WO, 11 / 06 / 2024 .

[0005] In conventional systems for laser irradiation of the workpiece using a laser beam directed onto the workpiece in the z-direction, the relative movement between the workpiece and the laser focus is achieved using xy linear axes, a galvanometer scanner, or a combination of both. With a galvanometer scanner, mirrors in the laser beam path are moved so that the laser beam scans an xy scan field. A major advantage of these systems is the geometric flexibility of the geometries, which can be created by meandering the beam across the scan field. However, the laser beam movements are discontinuous, i.e., the laser focus is decelerated and accelerated at reversal points in the xy plane. Especially with galvanometer scanners, the imageable scan fields are usually quite small, for example, in the range of a few millimeters, so that "stitching" is necessary for larger areas to be exposed.Stitching refers to the combination of multiple scan fields to expose a larger area. However, unwanted surface artifacts often occur at the transitions between the stitched scan fields.

[0006] Furthermore, in known laser irradiation systems, the feed rate of the laser focus in the xy plane is limited and is typically 200 mm / s. This limits the possible laser pulse rate due to local heat accumulation. The higher the feed rate of the laser focus in the xy plane, the shorter the dwell time of the laser focus at one point, so the laser pulse rate can be increased without locally overheating the workpiece. A higher feed rate of the laser focus in the xy plane would also have the advantage of reducing the total time required for laser irradiation of a workpiece, thus increasing productivity.

[0007] The limited feed rate of the laser focus in the xy plane over limited scan fields in known processes ultimately means that there are currently no inexpensive, mass-produced workpiece surfaces with a dimensional tolerance of less than 5 µm over an area of ​​at least 200 mm². However, these are urgently needed, for example, glass or glass-ceramic optics in the form of a Fresnel lens for photovoltaic concentrator modules. Photovoltaic concentrator modules, in which sunlight is concentrated and directed onto solar cells, have the advantage over conventional photovoltaic modules that less silicon is required per unit area. However, plastic Fresnel lenses are not durable enough for such applications.However, inexpensively manufactured workpiece surfaces with a dimensional tolerance of less than 5 µm over an area of ​​at least 200 mm² do not yet exist. A dimensional tolerance of less than 5 µm over an area of ​​at least 200 mm² is intended to mean that a peak-to-valley value (R) of 15 to 15 µm is achieved over the entire area of ​​at least 200 mm². t according to DIN EN ISO 4287) of 5 µm is not exceeded. Optics with such surfaces are also required in optical satellite communications, for example, for a Cassegrain telescope. But inexpensively manufactured workpiece surfaces with a dimensional tolerance 20 below 5 µm are also required in many other technical fields.

[0008] This results in the task of being able to produce workpiece surfaces with a dimensional tolerance of less than 5 µm on an area of ​​at least 200 mm² and with increased productivity in series.

[0009] According to a first aspect of the present disclosure, a device is provided to solve this problem for laser irradiation of a workpiece blank for producing a workpiece surface with a dimensional tolerance of less than 5 µm, the device comprising: - a rotating system configured to clamp a workpiece blank 30 and rotate it about a rotational axis at an adjustable speed, Patentanwälte Hemmer Lindfeld Frese INNP 3746 WO, 11 / 06 / 2024 - a laser system configured to direct a laser beam pulsed at an adjustable laser pulse rate onto or into a workpiece blank rotated by the rotating system and to focus it such that a laser focus is located at a variable radial distance from the rotational axis on or in the workpiece blank, - a control system configured toto control the laser focus by changing the radial distance of the laser focus along a programmable irradiation profile, wherein the control system is further configured to adapt the laser pulse rate of the laser system and the rotational speed of the rotary system as a function of the radial distance of the laser focus, wherein in a first range of radial distances the laser pulse rate of the laser system is adapted to the radial distance of the laser focus at a preferably constant rotational speed of the rotary system, and in at least a second range of radial distances the rotational speed of the rotary system is adapted to the radial distance of the laser focus at a preferably constant laser pulse rate of the laser system.

[0010] The turning system can essentially be a turning spindle known from machining, into which a cylindrical workpiece blank, for example, can be clamped. This allows workpiece blanks of almost any size to be exposed without stitching. The size of the workpiece surface to be produced is scalable without stitching and the associated loss of dimensional accuracy. The laser system can have a pulsed laser beam source and a laser beam path guide, preferably with two or more lenses. The laser beam preferably extends essentially parallel to and offset from the axis of rotation toward a front side of the workpiece blank facing the laser, so that the laser focus is located at an adjustable three-dimensional spatial point in or on the volume of the workpiece blank.Depending on whether laser ablation or exposure for SLE is involved, the material at the laser focus is vaporized or the material properties of the workpiece blank change there for SLE. For example, a glass or glass-ceramic blank can become milky and / or opaque as a side effect when exposed to SLE. The main effect is a change in the etching rate at the points, lines, or areas defined by the exposure profile within 5 of the volume of the workpiece blank along which the laser focus is guided.

[0011] By the polar kinematics used according to the invention in the xy-plane transverse to the axis of rotation running in the z-direction, ie via the polar coordinates ^^ = ^^2 + ^^2 as radial distance to the axis of rotation and10 ^^ = arctan as rotation angle position, where The preferably program-controlled speed of the rotary system allows the feed rate of the laser focus ^^ = ^^ × ^^ to be significantly increased compared to known laser scanners, for example, to several thousand mm / s. The laser pulse rate can be selected accordingly higher without locally overheating the workpiece blank. Furthermore, one is not limited to scan fields of a certain size and can irradiate large areas homogeneously without "stitching" and the associated surface artifacts. There are also far fewer braking and acceleration processes in the ^^ ^^ plane, so the laser beam guidance in the ^^ ^^ plane 20 is much more uniform than with meandering linear scanning in the xy plane. This allows for better dimensional accuracy over a larger area. Furthermore, the irradiation time per workpiece blank can be significantly reduced, which increases productivity and lowers production costs. 25

[0012] A further advantage of the polar kinematics used according to the invention compared to meandering linear scanning in the xy plane is the "stationary" laser beam, which is not moved via rotating mirrors. For example, acceleration and braking forces on the never massless mirrors regularly lead to deviations from the target position and / or speed of the laser focus during meandering linear scanning. In contrast, the optical axis of the laser system is fixed in the polar kinematics used according to the invention, thus avoiding many such negative influences on dimensional accuracy. 5

[0013] Preferably, a programmable path guidance along the irradiation profile, also called path planning, is carried out for the irradiation using CAM software based on 3D CAD data. For this purpose, the 3D CAD data can be broken down into levels, and the path data for the individual levels can be generated automatically. Using algorithms, the path planning can be optimized for traversing different irradiation profiles according to the cutting surfaces of the CAD model. Preferably, the "path guidance" is a programmed movement path through three-dimensional space, in which the feed rate of the laser focus along the movement path is defined at every point along the movement path. The volume to be traversed by the volume of the laser focus along the movement path forms the irradiation profile. The path guidance thus defines the irradiation profile in spatial terms.In terms of time, the path guidance defines at each point of the movement path the direction and the local feed rate at which the irradiation profile is traversed with the laser focus along the movement path. The same irradiation profile can therefore be traversed at different speeds or along different paths depending on the programmed path guidance. 25 .

[0014] The irradiation profile therefore defines the geometry of a workpiece surface that is cut directly from the workpiece blank by laser ablation or later etched out by SLE. Thus, the workpiece surface is preferably defined by what remains of the workpiece blank as the core and / or shell after laser cutting or etching out the irradiation profile. The polar kinematics used according to the invention is particularly suitable for machining rotationally symmetric workpiece surfaces, such as optical surfaces of spherical or aspherical lenses. Patent Attorneys Hemmer Lindfeld Frese INNP 3746 WO, 11 / 06 / 2024. Furthermore, non-rotationally symmetric irradiation profiles can also be irradiated by dynamically controlling the focus position of the laser beam, so that even non-rotationally symmetric workpiece surfaces can be produced.The irradiation profile can also define arbitrarily shaped lateral surfaces in order to achieve a correspondingly shaped cross-sectional format of the workpiece surface. For example, the workpiece blank can have a cylindrical shape with a circular cross-section, and the irradiation profile a polygonal cross-section. The diameter of the workpiece blank then only needs to be selected to be large enough so that the cross-sectional area of ​​the workpiece blank corresponds at least to the circumference completely enclosing the polygonal cross-section. Unneeded lateral or axial shell parts of the workpiece blank that lie outside the irradiated irradiation profile can then fall off after laser ablation or after etching, exposing the workpiece surface.Alternatively or additionally, the irradiation profile can define cores of the workpiece blank that are to be lost during laser cutting or etching, so that the workpiece surface can extend, among other things, into or over open cavities. The workpiece surface can therefore be curved and / or directed outward and / or inward. The workpiece surface can, for example, be or become at least partially coated with a reflective coating.

[0015] A challenge with the polar kinematics used according to the invention has been shown to be that the feed rate of the laser focus ^^ = ^^ × ^^ also becomes small at small radial distances ^^ =|^^| and the speed = | ^^| of the rotary system cannot be increased arbitrarily. However, with larger radial distances, the problem has been shown that high laser pulse rates of the laser system 30 cannot be adjusted arbitrarily. In order to achieve a high laser pulse rate in a first range of small radial distances, e.g., 0 ≤ ^^ ≤ ^^1 ,as well as in a second range of larger radial distances, e.g. ^^1≤ ^^ ≤ ^^2, to achieve a constant or specifically changed local laser energy input density across both ranges, the control system is designed according to the invention to adapt the laser pulse rate of the laser system and the speed of the rotary system as a function of the radial distance of the laser focus, wherein in the first range of smaller radial distances the laser pulse rate of the laser system is adapted to the radial distance of the laser focus at a preferably constant speed of the rotary system and in the second range of larger radial distances the speed of the rotary system is adapted to the radial distance of the laser focus at a preferably constant laser pulse rate of the laser system.The irradiation profile can be traversed with the laser focus either from the radial outside to the inside up to the rotation axis, or vice versa, from the rotation axis to the radial outside. It may also be useful to adapt both the rotational speed of the rotation system and the laser pulse rate of the laser system to the radial distance of the laser focus in the first range of smaller radial distances and / or in the second range of larger radial distances.

[0016] Optionally, the control system can be configured to keep a spatial laser pulse spacing on or in the workpiece blank constant over the first and the at least one second range of radial distances 20 or to change it in a targeted manner. The laser energy per laser pulse can thus remain unchanged and, thanks to the constant spatial laser pulse spacing, a constant local laser energy input density can be achieved over all ranges of radial distances, in particular up to the axis of rotation, i.e. ^^ = 0. However, if the laser energy per laser pulse changes with the laser pulse rate, it can be expedient to change the spatial laser pulse spacing on or in the workpiece blank in a targeted manner over the first and the at least one second range of radial distances.

[0017] Optionally, the control system can be configured to specifically change or adapt the laser energy per laser pulse of the laser system as a function of the radial distance of the laser focus, the speed of the rotating system, and / or the laser pulse rate. In particular, if the speed of the rotating system and / or the laser pulse rate of the laser system is changed during the transition between the first range of radial distances and the at least one second range of radial distances or during the transition between two second ranges of radial distances, it can be advantageous to specifically adapt the laser energy per laser pulse of the laser system. Alternatively or in addition to the laser energy per laser pulse of the laser system, an average laser power can be specifically changed or adapted as a function of the radial distance of the laser focus, the speed of the rotating system, and / or the laser pulse rate.This may be advantageous depending on the type and / or operating mode of the laser system.

[0018] Optionally, the control system can be configured to increase or decrease the laser pulse rate of the laser system 15 in the first range of radial distances proportionally with the radial distance of the laser focus. In the range of small radial distances from the rotation axis, the feed rate of the laser focus along the irradiation profile is correspondingly small, so that the laser pulses are spaced at a correspondingly high temporal interval in order to achieve a constant or freely definable spatial laser pulse spacing on or in the workpiece blank. In the first range of small radial distances, the laser pulse rate is therefore preferably scaled positively linearly with the radial distance. At the rotation axis, i.e. at ^^ = 0, the laser pulse rate is also zero. The upper limit ^^1 of the first range of small radial distances, e.g. 0 ≤ ^^ ≤ 25 ^^1, can be selected arbitrarily and programmed for path planning.Most suitable laser systems currently on the market allow continuous adjustment of the laser pulse rate only up to a certain upper limit. Therefore, the upper limit can be ^^ 1of the first range of small radial distances is determined by this limiting rate of the laser system. Patent Attorneys Hemmer Lindfeld Frese INNP 3746 WO, 11 / 06 / 2024

[0019] Optionally, the control system can be configured to reduce the speed of the rotary system in at least one second range of radial distances inversely with increasing radial distance or to increase it inversely with decreasing radial distance. 5 In the range of larger radial distances, the feed rate of the laser focus along the irradiation profile is correspondingly high, so that the speed is reduced accordingly in order to achieve a constant or freely definable spatial laser pulse spacing on or in the workpiece blank. The speed is therefore preferably scaled reciprocally to the radial distance in the second range 10 of larger radial distances. A lower limit of the second range of larger radial distances can be selected such that the speed is at a maximum of the speed range in which the speed is adjusted.An upper limit of the second range of larger radial distances can be selected accordingly so that the speed is at a minimum of the speed range in which the speed is adjusted. If the glass or glass ceramic to be manufactured requires larger radii, a further second range of even larger radial distances can be added radially outward, in which a suddenly higher laser pulse rate is set, so that in the radial distance range the speed can again be scaled reciprocally to the radial distance. Accordingly, there can be several second ranges of larger radial distances.

[0020] Optionally, the radial distances in the first range of radial distances can be smaller than in the at least one second range 25 of radial distances. Preferably, the first range of radial distances extends from the rotation axis to the second range of radial distances.

[0021] Optionally, a lower boundary of the at least one second region of larger radial distances can directly adjoin an upper boundary of the first region of smaller radial distances. Thus, the regions preferably adjoin one another seamlessly. Patent Attorneys Hemmer Lindfeld Frese INNP 3746 WO, 11 / 06 / 2024

[0022] Optionally, the control system can be configured to abruptly change the laser pulse rate at a transition between the first range of radial distances and the at least one second range of radial distances and to abruptly adjust the rotational speed of the rotary system 5, so that a spatial laser pulse spacing on or in the workpiece blank remains constant or changes in a targeted manner at the transition between the first range of radial distances and the at least one second range of radial distances. The radial traversing of the laser focus along the irradiation profile can preferably take place from the outside in, but if necessary also from the inside out. The term "abrupt" here refers to the change as a function of the radial distance of the laser focus. Over time, a "abrupt" change in the rotational speed can imply a certain adjustment time that the rotary system needs to increase or decrease the rotational speed 15.The laser beam can be stopped at the beginning of such an adjustment period, with the exact phase angle of the workpiece being recorded with the last laser pulse. The radial distance can also remain constant during the adjustment period. Once the rotary system has reached the target speed, the laser beam can be switched on again at the end of the adjustment period with a new laser pulse rate and precise timing, so that the first laser pulse after the adjustment period hits the workpiece at exactly the recorded phase angle.

[0023] Optionally, the control system can be configured to operate the 25 laser system in the first range of radial distances in a pulse-on-demand mode, also referred to as free-trigger mode, and to operate the laser system in the at least one second range of radial distances with an integer part of a reference laser pulse rate. The reference laser pulse rate can be, for example, 50 MHz to 30 MHz, so that in a so-called discrete partial pulse rate mode of the laser system, the laser pulse rate in the at least one second range of radial distances can be, for example, 50 / 1 = 50 MHz, 50 / 2 = 25 MHz, 50 / 3 = 16.67 MHz, 50 / 4 = 12.5 MHz, 50 / 5 = 10 MHz, 50 / 6 = 8.33 MHz, 50 / 7 = 7.14 MHz, 50 / 8 = 6.25 MHz, or 50 / 9 = 5.56 MHz. The laser system can be operated in a pulse-on-demand mode, for example, below a certain pulse rate, e.g., 5 MHz.In pulse-on-demand mode (=free-trigger mode), each individual laser pulse is freely triggered by a control signal from the control system. The advantage of pulse-on-demand mode is that the laser pulse rate can be reduced as required for small radial distances, for example, less than 5 mm from the rotational axis, without having to reduce the speed below a minimum speed. Pulse-on-demand mode is not suitable for larger radial distances in the second range, as only higher pulse rates can exploit a higher speed range to shorten the processing time. In discrete partial pulse rate mode, the laser pulse rate can only be adjusted in steps, but the speed can be continuously adjusted to the radial distance within a speed range.If the speed range for a discrete divider is exhausted, it is possible to switch to another discrete divider in order to fully utilize the speed range again. It may be useful to specifically set or adjust a laser energy per laser pulse in the laser system's pulse-on-demand mode and an average laser power of the laser system in the discrete partial pulse rate mode in order to achieve a constant local laser energy input density across all radial distance ranges. 25 .

[0024] Optionally, there may be several adjacent second ranges of radial distances and the control system may be configured to abruptly switch the laser pulse rate from one integer part of a reference laser pulse rate to another integer part of a reference laser pulse rate during the transition between the second ranges of radial distances and to abruptly adjust the rotational speed of the rotary system so that a spatial laser pulse distance on or in the workpiece blank remains constant or changes in a targeted manner during the transition between the second ranges of radial distances.

[0025] It has been found that after laser cutting or etching the irradiation profile, surface deviations on the workpiece surface with respect to a target geometry are sometimes measurable. These surface deviations can be above the desired maximum dimensional tolerance of 5 µm, for example, 15 µm or more on an optical surface with a 10 mm diameter. The surface deviations between the actual and target geometry after laser cutting or etching can have different causes and different characteristics. One can distinguish between low-frequency (shape), medium-frequency (waviness), and short-frequency defects (roughness). This applies particularly to workpiece surfaces with the highest demands on dimensional accuracy, such as the optical surfaces of refractive, reflective, or diffractive lenses.For some workpiece surfaces, the requirements for low-frequency errors (absolute form deviations) may be below 1 µm and medium-frequency errors (waviness) below 20 of 300 nm.

[0026] Undesired surface deviations can arise for the following reasons, among others. First, with SLE, the exposure time of the irradiation profile with the etching medium can be inhomogeneous. 25 Starting from an initial contact area with a specific etching rate, the etching medium can penetrate into the laser-exposed areas of the workpiece blank with increasing contact time. Although the etching rate for the surrounding glass or glass-ceramic in the non-laser-exposed area is significantly lower than in the laser-exposed area (approximately by a factor of 100-1000), this non-exposed material is also removed to a certain extent by the etchant. Accordingly, undesired, low-frequency and / or medium-frequency shape deviations of the final workpiece surface can occur.Secondly, in both laser ablation and SLE, the laser exposure parameters may need to be adjusted during the irradiation process, depending on the system. Adjusting the irradiation parameters can, in turn, affect the etching rate of the laser-exposed material. This results in laser-exposed areas within a workpiece with a different etching rate. Due to the inhomogeneous etching rate, contact with the etchant can cause shape deviations between the actual and target geometry. Thirdly, the irradiation profile can define one or more etching channels to shorten the process time and deliver the etchant more quickly to the workpiece areas to be etched. This can also lead to shape deviations between the actual and target geometry.Fourthly, both laser ablation and SLE 15 can result in spherical aberration due to the continuous tracking of the laser focus's penetration depth into the workpiece blank, which can change the caustic of the laser beam. The variable caustic shape can alter the absorption properties of the laser beam in the glass or glass-ceramic, which can also lead to surface deviations.

[0027] According to a further aspect of the present disclosure, in order to reduce undesirable surface deviations between the desired and actual geometry, a device is provided for exposing a glass or glass-ceramic blank for the production of a glass or glass-ceramic optic with a dimensional tolerance of less than 5 µm within the scope of a selective laser etching process (LSE), wherein the device comprises: - a rotation system configured to clamp a glass or glass-ceramic blank and rotate it about a rotation axis, - a laser system configured to direct a pulsed laser beam into a glass or glass-ceramic blank rotated by the rotation system and to focus it such that a laser focus is created. Patent Attorneys Hemmer Lindfeld Frese INNP 3746 WO,11 / 06 / 2024 with a local laser energy input density at a variable penetration depth in the direction of the rotation axis and at a variable radial distance from the rotation axis within the glass or glass-ceramic blank in order to cause material changes in the glass or glass-ceramic blank through the laser focus, - a control system which is configured to control the laser focus with a programmable path guidance along a programmable exposure profile within the glass or glass-ceramic blank by changing the penetration depth and the radial distance 10 (r) of the laser focus in the rotated glass or glass-ceramic blank, and - a correction system, wherein the correction system is configured to adapt the exposure profile and / or the path guidance and / or the local laser energy input density for a glass or glass-ceramic blank to be subsequently exposed in such a way that surface deviations,which are measurable on the glass or glass-ceramic optics after etching the exposure profile with respect to a target geometry, are reduced in a subsequently manufactured glass or glass-ceramic optic. 20 ,

[0028] According to this aspect of the invention, the correction system is thus intended to reduce such surface deviations by adapting the exposure profile, the path guidance, and / or the local laser energy input density for a glass or glass-ceramic blank to be subsequently exposed. Using an internal or external measuring system, the relevant optical surfaces on the etched glass or glass-ceramic optic can be measured to determine how much the actual geometry deviates from a target geometry. This can be done, for example, using a tactile or optical measuring point that is moved over the relevant optical surface of the etched glass or glass-ceramic optic.It should be noted at this point that the etching and measuring preferably take place externally from the exposure device, and data on the surface deviations are provided to the correction module of the exposure device. Alternatively, the measuring system can be part of the exposure device. It should be noted at this point that the irradiation profile for SLE can be referred to as an exposure profile, since the correspondingly exposed areas in the glass or glass-ceramic blank are later etched out.

[0029] Optionally, the laser system can further be configured to adjust the focusing of the laser beam depending on the penetration depth of the laser focus such that the local laser energy input density at the laser focus does not change by changing the penetration depth of the laser focus. This allows a change in the causticity of the laser beam caused by spherical aberration to be at least partially compensated, since the spherical aberration varies with the penetration depth of the laser focus. Certain parameters of this dynamic adjustment of the focusing of the laser beam to compensate for spherical aberration can be adjusted by the correction system if this allows measured surface deviations for glass or glass-ceramic optics to be subsequently manufactured to be reduced.

[0030] Optionally, the laser system can have at least two lenses and be configured to change the penetration depth of the laser focus by changing a distance between the at least two lenses. This is advantageous because it allows the rotation system and a laser beam source of the laser system to be fixedly arranged in the direction of the rotation axis. Changing the penetration depth of the laser focus can thus also be adjusted particularly quickly and precisely. A first of the two lenses has a smaller distance in the direction of the rotation axis from the glass or glass-ceramic blank than a second of the two lenses, whereby the position of the first lens in the direction of the rotation axis determines the penetration depth of the laser focus, and the position of the second lens in the direction of the rotation axis relative to the first lens determines the causticity of the laser focus. Patent Attorneys Hemmer Lindfeld Frese INNP 3746 WO, 11 / 06 / 2024

[0031] Optionally, the control system can also be configured to adjust a rotational speed of the rotary system and / or a pulse rate of the laser system depending on the radial distance of the laser focus from the rotational axis such that the local laser energy input density along the path guide is constant or can be specifically changed. This compensates for the effect of the path speed changing with the radial distance of the laser focus from the rotational axis at a specific angular speed. As long as the rotational speed can be adjusted within a certain range, the path speed, which corresponds to the feed rate of the laser focus, can be kept as constant as possible within this range by adjusting the rotational speed. For the most homogeneous exposure of the glass or glass-ceramic, high pulse-to-pulse stability of the pulse energy and duration of the laser beam is advantageous.A constant temporal and spatial pulse spacing for each exposure point within the exposure profile is also useful. Certain parameters of this dynamic adjustment of the rotational speed and / or laser pulse rate can be adjusted by the correction system to keep the local laser energy input density as constant as possible, provided this reduces measured surface deviations for subsequently manufactured glass or glass-ceramic optics.

[0032] In particular, the goal of a constant temporal and spatial pulse spacing is a technical challenge, since the feed rate of the laser focus along the movement path converges towards zero with decreasing distance from the rotation axis. For full-surface laser processing up to the rotation axis, the smallest path radius around the rotation axis is defined by the diameter of the laser beam or, in the case of track overlap, by a fraction of the laser beam diameter. Typical laser beam diameters for the SLE process are less than 10 µm. To achieve a constant feed rate of 1,000 mm / s, an unrealistically high speed of 3.2 × 10 5 Revolutions per second with the highest possible positioning accuracy are required. Patent Attorneys Hemmer Lindfeld Frese INNP 3746 WO, 11 / 06 / 2024

[0033] The laser system is therefore preferably configured to provide the pulsed laser beam with a variable laser pulse energy per laser pulse, wherein the control system is configured to control the local laser energy input density by changing the laser pulse rate and / or the laser pulse energy per laser pulse. For example, the laser system can have a basic laser pulse rate of 40 MHz. Then, in a first control mode, for example to reduce the local laser energy input density, only even or odd multiples of the laser pulse rate can be selected, e.g., every second pulse (20 MHz) or every fourth pulse (10 MHz), etc. Below a certain laser pulse rate, e.g., below 5 MHz, any pulses can be selected in a second control mode. The second control mode can therefore also be referred to as "pulse-on-demand mode" or "free-trigger mode."The pulse-on-demand mode is particularly useful for exposing areas very close to the rotation axis. In conjunction with a gradual change in the rotational speed, the pulse spacing can be kept relatively constant both spatially and temporally by changing the laser pulse rate. The control system is preferably programmable accordingly, with the correction system being able to adapt the control system programming accordingly if this reduces measured surface deviations for subsequently manufactured glass or glass-ceramic optics.

[0034] Optionally, the rotation system can be movable transversely to the rotation axis, and the control system can be configured to control the radial distance 30 of the laser focus by moving the rotation system transversely to the rotation axis. This has the advantage that the laser system can be spatially fixed. The exposure profile can be traversed from the inside out, i.e., with an increasing radial distance, or from the outside in, i.e., with a decreasing radial distance. Preferably, the radial distance is traversed only once in one direction when exposing an optical surface. The mass of the rotation system therefore needs little or no acceleration or deceleration transversely to the rotation axis during exposure, but can be moved transversely to the rotation axis at a uniform speed during exposure.An initial acceleration and / or a final braking process transverse to the rotation axis can take place outside of the exposure time, ie the laser system can be triggered accordingly to direct and focus the laser beam only in a specific time window onto the glass or glass-ceramic blank that is constantly moving past transverse to the rotation axis and rotated about the rotation axis.

[0035] Preferably, the laser focus is set in the vertical y-direction at the height of the rotation axis, so that only a linear movement of the laser focus in the x-direction and in the z-direction of the penetration depth parallel to the rotation axis relative to the glass or glass-ceramic blank is possible. The positioning of the laser focus in the x'y'-plane in the x'y'z' reference system of the rotated glass or glass-ceramic blank can be achieved by the known instantaneous position of the rotation angle ^^ with ^^′ = ^^′ ∙ cos( ^^′) and ^^′ = ^^′ ∙20 sin( ^^′), where ^^ ′ =^^′2 + ^^′2= ^^ = ^^, ^^ = 0, ^^ ′ = ^^ and ^^ ′ = ^^ ^^ ^^ ^^ ^^ ^^ ^^′ ^^′ = ― ^^.

[0036] Optionally, the exposure profile can define one optical surface or two opposing optical surfaces of the glass or glass-ceramic optic. The dimensional tolerance of less than 5 µm 25 is primarily required for the optical surface(s). The advantage of the SLE process over direct machining or direct laser ablation lies in the fact that two opposing optical surfaces of the glass or glass-ceramic optic can be exposed without having to remove the glass or glass-ceramic blank from the turning system. This ensures that the optical surfaces are always precisely aligned with each other. Patent Attorneys Hemmer Lindfeld Frese INNP 3746 WO, 11 / 06 / 2024

[0037] Optionally, the exposure profile can define at least one etching channel extending from the optical surface or from at least one of the two opposing optical surfaces to a front or back side of the glass or glass-ceramic blank. The etchant can then eat its way along the at least one etching channel during etching. The at least one etching channel is preferably arranged such that the etchant reaches the optical surface at as many points as possible at the same time, so that the time each surface point of the optical surface is exposed to the etchant is approximately the same. If there are multiple etching channels, these are distributed accordingly. The at least one etching channel preferably has an annular cross-section and preferably extends as a ring cylinder through the glass or glass-ceramic blank from the optical surface to the front or back side of the glass or glass-ceramic blank.

[0038] Optionally, the exposure profile can define a first optical surface of the glass or glass-ceramic optic and a second optical surface of the glass or glass-ceramic optic, with the first optical surface being further away from the laser system in the direction of the rotation axis than the second optical surface. The path guidance along the exposure profile is programmed such that the first optical surface is traversed by the laser focus before the second optical surface. The rear optical surface with the greater penetration depth for the laser focus is therefore preferably exposed first, followed by the front optical surface with the lower penetration depth. This is advantageous because the glass or glass-ceramic blank can become cloudy at the laser focus due to exposure.

[0039] Optionally, the exposure profile can define at least one first etching channel and at least one second etching channel, wherein the at least one first etching channel extends from the first optical surface to a rear side of the glass or glass-ceramic blank facing away from the laser system, and the at least one second etching channel extends from the second optical surface to a front side of the glass or glass-ceramic blank facing the laser system. The etching channels extend through a volume of the glass or glass-ceramic blank that is to be lost during etching and enable the most uniform etching time possible for both optical surfaces when the exposed glass or glass-ceramic blank is immersed in the etchant.Radially outward, one of the first etching channels and one of the second etching channels can form an outer surface that defines the cross-sectional shape 10 of the glass or glass-ceramic optic. The cross-sectional shape of the glass or glass-ceramic optic can be circular, polygonal, or of another shape.

[0040] Optionally, the exposure device can have a measuring system for measuring surface deviations with respect to a target geometry after etching the exposure profile, wherein the measuring system is configured to guide a tactile or optical measuring point over an optical surface of a glass or glass-ceramic optic clamped and rotated in the rotating system. The exposed glass or glass-ceramic blank is thus removed from the rotating system after exposure for etching, and the etched glass or glass-ceramic optic is then re-clamped to measure the surface deviations. The measuring point is guided over the optical surface essentially in the same way as the laser beam focus during exposure.

[0041] As an alternative to an internal measuring system, the exposure device can optionally have a data interface for receiving data on surface deviations with respect to a target geometry 30 after etching the exposure profile, which were measured using an external measuring system. This is particularly advantageous because the exposure device is then used efficiently and exclusively for the exposure of glass or glass-ceramic blanks in series. The feedback of data on surface deviations can be carried out regularly, preferably at the beginning of series production after each exposed glass or glass-ceramic blank, and later less frequently to check and maintain surface quality. 5

[0042] Optionally, the correction system can be integrated into the control system or installed on a computer separate from the control system. Regardless of whether the correction system is integrated into the control system or not, it provides a data set as output that defines an adjusted exposure profile and / or an adjusted 10 path and / or an adjusted local laser energy input density. The control system then converts this data set into control commands for the glass or glass-ceramic blank to be subsequently exposed and controls the exposure device accordingly. 15

[0043] According to a further aspect of the present disclosure, a method is provided for laser irradiating a workpiece blank for producing a workpiece surface with a dimensional tolerance of less than 5 µm, the method comprising: - rotating a workpiece blank clamped in a rotating system at an adjustable speed about a rotational axis, - directing and focusing a laser beam pulsed at an adjustable laser pulse rate into or onto the rotated workpiece blank by means of a laser system, such that a laser focus is located at a variable radial distance from the rotational axis on or in the workpiece blank, - controlling the laser focus along a programmable irradiation profile by changing the radial distance of the laser focus, - adjusting the laser pulse rate of the laser system and the speed of the rotating system depending on the radial distance of the laser focus,wherein in a first range of radial distances, the laser pulse rate of the laser system is adapted to the radial distance of the laser focus at a preferably constant speed of the rotary system, and in at least a second range of radial distances, the speed of the rotary system is adapted to the radial distance of the laser focus at a preferably constant laser pulse rate of the laser system. 5 ,

[0044] Optionally, a spatial laser pulse spacing on or in the workpiece blank can be kept constant over the first and at least one second range of radial distances. 10

[0045] Optionally, in the first range of radial distances, the laser pulse rate of the laser system can be increased or decreased proportionally with the radial distance of the laser focus.

[0046] Optionally, in the at least one second range of radial distances, the speed of the rotary system can be reduced inversely with increasing radial distance of the laser focus or increased inversely with decreasing radial distance of the laser focus.

[0047] Optionally, the radial distances in the first range of radial distances can be smaller than in the at least one second range of radial distances.

[0048] Optionally, a lower limit of the at least one second range of radial distances can directly adjoin an upper limit of the first range of radial distances.

[0049] Optionally, the laser pulse rate can be changed abruptly at a transition between the first range of radial distances and the at least one second range of radial distances, and the rotational speed of the rotary system can be adjusted abruptly, so that a spatial laser pulse spacing on or in the workpiece blank remains constant at the transition between the first range of radial distances and the at least one second range of radial distances. Patent Attorneys Hemmer Lindfeld Frese INNP 3746 WO, 11 / 06 / 2024

[0050] Optionally, the laser system can be operated in a pulse-on-demand mode in the first range of radial distances and the laser system can be operated in the at least one second range of radial distances with an integer part of a reference laser pulse rate 5.

[0051] Optionally, there may be several adjacent second ranges of radial distances and the laser pulse rate can be switched abruptly from one integer part of a reference laser pulse rate to another integer part of a reference laser pulse rate at the transition between the second ranges of radial distances and the speed of the rotary system can be adjusted abruptly so that a spatial laser pulse distance on or in the workpiece blank remains constant at the transition between the second ranges of radial distances.

[0052] According to a further aspect of the present disclosure, a method is provided for exposing a glass or glass-ceramic blank for the production of a glass or glass-ceramic optic with a dimensional tolerance of less than 5 µm in a selective laser etching process (LSE), the method comprising: - rotating a glass or glass-ceramic blank clamped in a rotating system about a rotation axis, - directing and focusing a pulsed laser beam into the rotated glass or glass-ceramic blank by means of a laser system, such that a laser focus with a local laser energy input density lies at a variable penetration depth in the direction of the rotation axis and at a variable radial distance from the rotation axis within the glass or glass-ceramic blank in order to effect material changes in the glass or glass-ceramic blank through the laser focus,- Controlling the laser focus with a programmable path guide along a programmable exposure profile within the glass or glass-ceramic blank by changing the penetration depth and the radial distance of the laser focus in the turned glass or glass-ceramic blank, and - Adapting the exposure profile and / or the path guide and / or the local laser energy input density for a glass or glass-ceramic blank to be subsequently exposed, so that surface deviations measured on the glass or glass-ceramic optic after etching the exposure profile with respect to a target geometry are reduced in a subsequently manufactured glass or glass-ceramic optic. 10 ,

[0053] Preferably, the method is carried out by means of a previously described exposure device.

[0054] Optionally, the process can be repeated iteratively until the measured surface deviations of the glass or glass-ceramic optics are below a dimensional tolerance of 5 µm, preferably below 2 µm. This can be achieved in just one or two iterations, so that only the first or second glass or glass-ceramic optic may not yet meet the dimensional tolerance requirements.

[0055] Optionally, the focus of the laser beam can be adjusted depending on the penetration depth of the laser focus so that the local laser energy input density at the laser focus does not change by changing the penetration depth of the laser focus. This compensates for a change in the causticity of the laser beam caused by spherical aberration, since the spherical aberration varies with the penetration depth of the laser focus.

[0056] Optionally, the penetration depth of the laser focus can be changed by changing the distance between at least two lenses of a laser system. This is advantageous because neither the rotation system nor a laser beam source of the laser system need to be moved in the direction of the rotation axis. Patent Attorneys Hemmer Lindfeld Frese INNP 3746 WO, 11 / 06 / 2024. This also allows the change in the penetration depth of the laser focus to be adjusted particularly quickly and precisely.

[0057] Optionally, a rotational speed of the rotary system and / or a pulse rate of the laser system can be adjusted depending on the radial distance of the laser focus from the rotation axis so that the local laser energy input density along the path guide is constant.

[0058] Optionally, the radial distance of the laser focus can be controlled by moving the rotation system transversely to the rotation axis. This has the advantage that the optical axis of the laser system can be spatially fixed. The exposure profile can be traversed from the inside out, i.e., with an increasing radial distance, or from the outside in, i.e., with a decreasing radial distance. 15 Preferably, the radial distance is only traversed once in one direction during exposure. The mass of the rotation system therefore needs little or no acceleration or deceleration transversely to the rotation axis during exposure, but can be moved at a constant speed transversely to the rotation axis during exposure. An initial acceleration and / or a final deceleration transversely to the rotation axis can take place outside of the exposure, i.e.The laser system can be triggered accordingly to direct and focus the laser beam only within a specific time window onto the glass or glass-ceramic blank, which is constantly moving past it transversely to the axis of rotation and rotated about the axis of rotation.

[0059] Optionally, the exposure profile can define one optical surface or two opposing optical surfaces of the glass or glass-ceramic optic. 30

[0060] Optionally, the exposure profile can define at least one etching channel extending from the optical surface of the glass or glass-ceramic optic to a front or back side of the glass or glass-ceramic blank. Patent Attorneys Hemmer Lindfeld Frese INNP 3746 WO, 11 / 06 / 2024

[0061] Optionally, the exposure profile can define a first optical surface of the glass or glass-ceramic optics and a second optical surface of the glass or glass-ceramic optics, wherein the first optical surface is further away from the laser system in the direction of the rotation axis than the second optical surface, wherein the path guidance along the exposure profile is programmed such that the first optical surface is traversed by the laser focus before the second optical surface. 10

[0062] Optionally, the exposure profile can define at least one first etching channel and at least one second etching channel, wherein the at least one first etching channel extends from the first optical surface to a rear side of the glass or glass-ceramic blank facing away from the laser system, wherein the at least one second etching channel extends from the second optical surface to a front side of the glass or glass-ceramic blank facing the laser system, wherein the path guidance along the exposure profile is programmed such that the at least one first etching channel is traversed by the laser focus before the first optical surface and the at least one second etching channel after the second optical surface.

[0063] According to a further aspect of the present disclosure, a method is provided for producing a glass or glass-ceramic optic with a dimensional tolerance of less than 5 µm by means of selective laser etching (LSE), the method comprising: - exposing a glass or glass-ceramic blank according to the previously described exposure method, - etching out the exposure profile, and - measuring the surface deviations of the glass or glass-ceramic optic after etching out the exposure profile with respect to a desired geometry. Patent Attorneys Hemmer Lindfeld Frese INNP 3746 WO, 11 / 06 / 2024

[0064] The measurement of surface deviations of the glass or glass-ceramic optic can be performed on the first glass or glass-ceramic optic(s) in a production run for each glass or glass-ceramic optic. Once the exposure profile and / or the path and / or the local laser energy input density have been adjusted so that the surface deviations are below the required dimensional tolerance, the measurement can only be performed randomly or discontinued when process conditions are stable. 10

[0065] Optionally, the glass or glass-ceramic blank can be removed from the rotating system for etching the exposure profile and the etched glass or glass-ceramic optic can be clamped back into the rotating system for measuring the surface deviations, whereby a tactile or optical measuring point is guided over an optical surface of the 15 glass or glass-ceramic optics clamped and rotated in the rotating system.

[0066] Alternatively, the glass or glass-ceramic blank can be removed from the rotary system for etching the exposure profile, and the surface deviations can be measured in a measuring system, preferably external to the exposure device, whereby data on the surface deviations are provided by the measuring system for adjusting the exposure profile and / or the path guidance and / or the local laser energy input density. 25

[0067] Optionally, the surface deviations of the glass or glass-ceramic optics can be corrected at least partially by laser ablation on an optical surface of the glass or glass-ceramic optics clamped and rotated in the rotation system. 30

[0068] According to a further aspect of the present disclosure, a glass or glass-ceramic optic is provided which is manufactured using a manufacturing method previously described by Patentanwälte Hemmer Lindfeld Frese INNP 3746 WO, 11 / 06 / 2024 with a dimensional accuracy tolerance below 5 µm.

[0069] Optionally, the glass or glass-ceramic optic can be designed rotationally symmetrical to the rotation axis, in particular in the form of a single-sided or double-sided spherical or aspherical lens. A major advantage of the exposure method disclosed herein is that the glass or glass-ceramic optic blanks can be exposed on both sides, with a front and a rear optical surface, each with a dimensional tolerance of less than 5 µm, since the glass or glass-ceramic blank does not have to be removed from the rotation system between exposures of the optical surfaces. Therefore, precise alignment of the optical surfaces to one another is guaranteed, which is particularly important and demanding in terms of manufacturing technology, especially for double-sided aspherical lenses.Therefore, the glass or glass-ceramic optic is preferably designed as a double-sided aspherical lens, in which one of the optical surfaces is arranged on the front and one on the back of the glass or glass-ceramic optic. 20 .

[0070] Optionally, the glass or glass-ceramic optics can be designed to be non-rotationally symmetrical to the axis of rotation, in particular in the form of a contact lens, a spectacle lens, an exposure optic, a mirror surface to be coated or a microstructured optic, wherein the glass or glass-ceramic optics has an optical surface on one or both sides.

[0071] Optionally, the glass or glass-ceramic optics can be designed in the form of a Fresnel lens and / or with a blazed grating or a diffractive surface structure. Such glass or glass-ceramic optics in the form of a Fresnel lens could be used, for example, for photovoltaic concentrator modules.

[0072] Optionally, the glass or glass-ceramic optic can have an optical front and an optical back, with at least one surface area of ​​the optical front and / or the optical back being coated with a reflective coating, preferably inwardly reflective. Such a glass or glass-ceramic optic can be used, for example, to provide a Cassegrain telescope for satellite communications. 5

[0073] Optionally, the at least one mirror-coated surface area of ​​the optical front side can be convexly curved when viewed from the inside and / or the at least one mirror-coated surface area of ​​the optical rear side can be concavely curved when viewed from the inside.

[0074] The glass or glass-ceramic optic according to the invention can be solid, so that the intended optical beam path between the optical surfaces on the front and back runs through the glass or glass-ceramic. The reflective coating then reflects into the glass or glass-ceramic. The advantage of a solid glass or glass-ceramic optic is its stability. The disadvantage is its high weight. However, the glass or glass-ceramic optic can also be manufactured as an open hollow form with at least one lost core during etching, so that the intended optical beam path between the optical surfaces on the front and back is essentially free of material. The reflective coating then reflects into the open cavity formed by the glass or glass-ceramic optic. The advantage of a hollow form is its reduced weight. The disadvantage is its lower stability.Therefore, a solid glass or glass-ceramic optic is suitable for stationary applications on the ground, while a hollow form could be advantageous for applications on a satellite.

[0075] The system disclosed herein is explained in more detail below with reference to the attached figures. They show: Patent Attorneys Hemmer Lindfeld Frese INNP 3746 WO, 11 / 06 / 2024 Fig. 1 shows a schematic plan view of an embodiment of an exposure device according to the present disclosure; Fig. 2a shows a schematic view of an embodiment of a glass or glass-ceramic blank during exposure; Fig. 2b shows a schematic view of an optical surface of an embodiment of a glass or glass-ceramic optic with spiral path guidance of the laser focus; Fig. 3 shows three exemplary diagrams showing the spatial laser pulse spacing along the irradiation profile, the rotational speed of the rotary system, and the laser pulse rate, each plotted against the radial distance; Figs. 4a, b show schematic views of an embodiment of a glass or glass-ceramic blank at different times during exposure;5a,b show schematic views of an embodiment of a glass or glass-ceramic blank at different times during exposure; Fig. 6a shows a schematic view of an embodiment of a glass or glass-ceramic optic when measuring surface deviations; Fig. 6b shows a schematic view of an embodiment of an adapted exposure profile for correcting the surface deviations according to Fig. 5a; Patent Attorneys Hemmer Lindfeld Frese INNP 3746 WO, 11 / 06 / 2024 Fig. 7a shows a schematic view of an embodiment of a glass or glass-ceramic blank with annular etching channels; Fig. 7b shows a schematic partial view of an embodiment of a glass or glass-ceramic blank with etching channels; Fig. 8a,b show schematic views of an embodiment of a glass or glass-ceramic blank with different penetration depths of the laser focus during exposure; Fig.9 shows a schematic flow diagram of an embodiment of a manufacturing method according to the present disclosure; Figs. 10a-f show schematic views of various embodiments of glass or glass-ceramic optics according to the present disclosure; and Figs. 11a-c show schematic views of further various embodiments of glass or glass-ceramic optics according to the present disclosure.

[0076] Fig. 1 shows an irradiation device 1 according to the invention during the irradiation of a workpiece blank in the form of a glass or glass-ceramic blank 3 in order to produce a glass or glass-ceramic optic with a workpiece surface that satisfies a dimensional tolerance of less than 5 µm by laser ablation or selective laser etching (LSE). The irradiation device 1 has a rotation system 5 in which the glass or glass-ceramic blank 3 is clamped and rotates it about a horizontal axis of rotation C. In each of the figures, a right-handed Cartesian coordinate system is shown in which the z-axis runs in the direction of the axis of rotation C and the x-axis runs horizontally transversely to the axis of rotation C. The y-axis runs vertically upwards. Patentanwälte Hemmer Lindfeld Frese INNP 3746 WO, 11 / 06 / 2024 Fig. 1 is therefore a plan view of the irradiation device 1 from above.The terms “radial outside” and “radial inside” refer to the x-axis, the terms “top” and “bottom” refer to the y-axis and the five terms “front”, “back”, “front-” and “back-” refer to the z-axis.

[0077] The irradiation device 1 also has a laser system 7, which directs a pulsed laser beam 9 onto the glass or glass-ceramic blank 3 rotated by the rotation system 5 and focuses it therein. The laser system 7 has a stationary laser beam source 11, which provides the pulsed laser beam 9 in the negative z-direction. The laser system 7 also has a laser beam path guide 13 with at least two lenses 15a, b. A first lens 15a of the two lenses 15a, b of the laser beam path guide 13 is a diverging lens, and the second lens 15b of the lenses 15a, b is a converging lens arranged in the beam path behind the diverging lens 15a, which focuses the expanded laser beam 9 in the glass and glass-ceramic blank 3 in a laser focus 17. The laser focus 17 is located at an adjustable penetration depth E, which is defined by the distance of the laser focus 17 in the z-direction from a front side 19 of the glass or glass-ceramic blank 3.In the illustrated embodiment 20 of the irradiation device 1, the rotation system 5 and thus the glass or glass-ceramic blank 3 clamped therein are arranged at a fixed z-position. The penetration depth E of the laser focus 17 is adjustable here by a linearly adjustable z-position of the laser beam path guide 13. Furthermore, the distance between the two lenses 15a,b within the laser beam path guide 13 is adjustable in order to adapt the focusing to the penetration depth E of the laser focus 17 and thus compensate for spherical aberration.

[0078] In the vertical y-direction, the laser focus 17 is fixed at the height of the horizontal rotation axis C. The vertical height of the rotation axis C in the y-direction is also constant. The laser focus 17 has an adjustable radial distance r from the rotation axis C in the x-direction because the rotation system 5 is mounted for linear movement in the direction of the x-axis. Patent Attorneys Hemmer Lindfeld Frese INNP 3746 WO, 11 / 06 / 2024

[0079] The laser focus 17 is thus located at a variable penetration depth E in the direction of the rotation axis C and at a variable radial distance r from the rotation axis C within the glass and glass-ceramic blank 3 in order to vaporize the material of the glass or glass-ceramic blank 3 during laser ablation or to effect material changes in the glass or glass-ceramic blank 3 in the laser focus 17 during SLE. Primarily, the material change for SLE means a significant increase in the etching rate by a factor of 100 to 1,000 compared to the areas of the glass or glass-ceramic blank 3 that are not irradiated with the laser focus 17. If the glass or glass ceramic optics to be produced from the glass or glass ceramic micro blank 3 are rotationally symmetrical, the irradiation can be carried out essentially independently of the current rotational angle position ^ of the glass or glass ceramic blank 3.For the production of non-rotationally symmetrical glass or glass-ceramic optics, however, the laser system 7 can be synchronized in time with the rotation system 5 such that a laser pulse is focused at the laser focus 17 at a very specific point in the volume of the glass or glass-ceramic microblank 3, which is clearly defined by the current penetration depth E, the current radial distance r from the rotation axis C, and the current rotation angle position ^. This makes it possible in principle to irradiate any desired irradiation profile 21 within the glass or glass-ceramic blank 3. In Fig. 1, a programmed irradiation profile 21 is shown as an example in dashed lines within the glass or glass-ceramic blank 3.

[0080] The irradiation device 1 further comprises a control system 23 configured to control the laser focus 17 with a programmable path guidance along the programmable irradiation profile 30 21 within the glass or glass-ceramic blank 3 by varying the penetration depth E and the radial distance r of the laser focus 17 in the rotated glass or glass-ceramic blank 3. For this purpose, the control system 23 is signal-connected to the laser system 7 and the rotary system 5 in order to control the laser system 7 and the rotary system 5 in a synchronized manner. The control system 23 determines the rotational speed ^ and the x-position of the rotary system 5, which determines the radial distance r, at any time during the irradiation. In addition, the control system 23 controls the current z-position of the laser beam path guide 13 and thus the penetration depth E of the laser focus 17.The control system 23 also controls the distance between the lenses 15a,b and the instantaneous pulse rate 10 of the laser beam source 11. As a result, the control system 23 also controls the instantaneous local laser energy input density at the laser focus 17.

[0081] Finally, in the embodiments shown in Fig. 1, the irradiation device 1 comprises a correction system 25, 25'. Fig. 1 simultaneously shows two possible embodiments, in which the correction system 25 is integrated into the control system 23 and in which the correction system 25' is installed as a correction system 25' on a computer 27 separate from the control system 23, for example, in a cloud. If the correction system 25' is installed externally from the control system 23, the control system 23 can have a data interface 29 to receive an adapted update from the correction system 25' for controlling the laser system 7 and the rotation system 5.Even in an embodiment in which the correction system 25 is integrated into the control system 23, the data interface 29 is useful for receiving data on surface deviations with respect to a desired geometry after etching the irradiation profile 21, which were measured by means of an external measuring system (not shown).

[0082] The correction system 25, 25' is configured to adapt the irradiation profile 21 and / or the path guidance and / or the local laser energy input density for a glass or glass-ceramic blank 3 to be subsequently exposed in such a way that surface deviations, which are measurable on the glass or glass-ceramic optic after etching the irradiation profile 21 with respect to a target geometry, are reduced in a subsequently manufactured glass or glass-ceramic optic. The etching of the irradiation profile 21 and the measurement of the surface deviations preferably take place externally of the irradiation device 1.

[0083] Fig. 2a shows the glass or glass-ceramic blank 3 alone and in more detail during irradiation with the laser focus 17. The glass or glass-ceramic blank 3 here has a circular-cylindrical shape with a front side 19, a rear side 31, and a lateral surface 33. The lateral surface 33 is clamped in a chuck (not shown here) of the rotary system 5. A core 35 of the glass or glass-ceramic blank 3 is provided to form the glass or glass-ceramic optic 35 to be produced after the irradiation profile 21 has been cut out or etched out. The glass or glass-ceramic optic 35 to be produced should later have a rear first optical surface 37 and a front second optical surface 39. In addition, the glass or glass-ceramic optic 35 to be produced should have a lateral surface 41.In order to expose the glass or glass-ceramic blank 3 within the scope of SLE for subsequent etching with the laser focus 17, the control system 23 is programmed with an exposure profile 21 that defines the areas to be exposed within the volume of the glass or glass-ceramic blank 3. In addition to the optical surfaces 37, 39 to be produced and the lateral surface 41 of the glass or glass-ceramic optics 35, the exposure profile 21 also defines etching channels 43a-d. The two rear first etching channels 43a,b extend from the rear first optical surface 37 in the shape of a circular cylinder shell backwards to the rear side 31 of the glass or glass-ceramic blank 3. The two front second etching channels 43c,d extend from the front second optical surface 39 in the shape of a circular cylinder shell forwards to the front side 19 of the glass or glass-ceramic blank 3.If the fully exposed glass or glass-ceramic blank 3 is immersed in a bath containing an etching medium, the etching medium eats away at the etching channels 43a, d along and across the surfaces 37, 39, and 41. The shell regions of the glass or glass-ceramic blank 3 located outside the core 35 are lost during etching. It should be noted at this point that if the irradiation profile 21 is cut out by laser ablation, no etching channels 43a-d are required.

[0084] Fig. 2a shows a situation in which the two rear first etching channels 43a,b have already been exposed for SLE and the rear first optical surface 37 is currently being exposed radially from the inside outwards. Since the laser focus 17 causes laser energy to be introduced into the glass or glass-ceramic, which leads to a desired material change, the material exposed with the laser focus 17 becomes milky as a side effect. It is therefore advisable to begin the exposure with the greatest penetration depth E and to successively reduce the penetration depth E over the exposure period. It is therefore advisable to first expose the rear first etching channels 43a,b, then the first rear optical surface 37, then the lateral surface 41, then the second front optical surface 39 and finally the front, second etching channels 43c,d.The lateral surface 41 could also be exposed together with the outer etching channels 43a,c as a circular cylindrical lateral surface extending completely from the rear side 31 to the front side 19. It should be noted at this point that the lateral surface 41 does not have to have a circular cross-section, but can be of any shape, for example, polygonal. 25 .

[0085] Fig. 2b schematically shows how one of the optical surfaces 37, 39 is homogeneously irradiated by a spiral-shaped path guide 45 of the laser beam focus 17 during laser ablation or SLE. The control system 23 is programmed such that the laser beam focus 17 is guided, for example, with a radial extension of 10 µm and, if desired, with a track overlap 30, along the programmed path guide 45 such that the local laser energy input density is as constant or determinately variable as possible in time and spatially along the path guide 45. Patent Attorneys Hemmer Lindfeld Frese INNP 3746 WO, 11 / 06 / 2024. Laser pulses are therefore distributed as homogeneously as possible across the entire surface 37, 39 with an identical or determinately variable spatial laser pulse spacing d.For this purpose, on the one hand, the instantaneous rotational speed ^ is adjusted so that the feed rate ^^ of the laser focus 17 is constant or determinately variable, independent of the instantaneous radial distance r of the laser focus 17 from the rotational axis C. In addition, the laser pulse rate f is adjusted in order to achieve a homogeneous distribution of the laser pulses over the optical surface 10 37, 39. .

[0086] Fig. 3 shows in more detail, using an example, how this inventive adjustment of the rotational speed ^ and the laser pulse rate f is carried out in order to achieve a constant or deterministically variable spatial laser pulse spacing d along the entire path guide 45. The control system 23 is set up here to adjust the laser pulse rate f of the laser system 7 and the rotational speed ^ of the rotary system 5 depending on the radial distance r of the laser focus 17, wherein in a first range A of radial distances the laser pulse rate f of the laser system 7 at preferably constant speed ^ min of the rotary system 5 20 is adapted to the radial distance r of the laser focus 17 and in at least one second range B, C, D, E of radial distances r, the rotational speed ^ of the rotary system 5 is adapted to the radial distance r of the laser focus 17, preferably with a constant laser pulse rate f of the laser system 7. It should be noted at this point that the ranges A, B, C, D, E here 25 each cover an equally large range of radial distances r. The limits However, ^^2, ^^3, ^^4, ^^5 can be specified as needed and programmed into the path planning, so that the ranges A, B, C, D, and E can have different widths. The respective jumps in the laser pulse rate f can also be specified as needed and programmed into the path planning. The speed range between a minimum speed ^^ ^^ ^^ ^^and a maximum speed Patent Attorneys Hemmer Lindfeld Frese INNP 3746 WO, 11 / 06 / 2024 ^^ ^^ ^^ ^^ does not have to be the same for the second areas B, C, D, E as shown, but can vary as required.

[0087] It may be useful not to keep the rotational speed ^ of the rotary system 5 constant in the first range A of radial distances, but to vary it in a determined manner. This may be useful, for example, if the laser energy per laser pulse changes with the laser pulse rate f of the laser system 7. By adjusting the rotational speed ^ accordingly, min This can be compensated for. It may therefore be useful in the first range A of radial distances or also in the at least one second range B, C, D, E of radial distances r to adapt both the laser pulse rate f of the laser system 7 and the rotational speed ^ of the rotary system 5 to the radial distance r of the laser focus 17.

[0088] Fig. 4a,b and 5a,b illustrate the exposure sequence for the SLE. In Fig. 4a, the rear first etching channels 43a,b are exposed first. In Fig. 4b, the rear first optical surface 37, then the lateral surface 41, and finally the front second optical surface 39 are exposed. In Fig. 5a, the front second etching channels 43c,d are finally exposed. The completely exposed glass or glass-ceramic blank 3 is shown in Fig. 5b. The entire exposure profile 21 is then exposed within the glass or glass-ceramic blank 3, so that the glass or glass-ceramic blank 3 can be removed from the rotating system 5 in order to etch out the exposed exposure profile 21. The glass or glass ceramic blank 3 disintegrates into the core 35, which forms the glass or glass ceramic optic 35 to be produced, and lost shell parts.

[0089] Fig. 6 shows a glass or glass-ceramic optic 35 after it has been etched out of the glass or glass-ceramic blank 3 and while the optical surfaces 37, 39 are measured for surface deviations that are measurable on the glass or glass-ceramic optic 35 after the exposure profile 21 has been etched out with respect to a target geometry 47. The surface deviations are exaggerated in Fig. 6a for clarity. To measure the surface deviations, a measuring system (not shown here) is used, which is configured to guide a tactile or optical measuring point 49 over the optical surfaces 37, 39.Preferably, the measurement of surface deviations takes place analogously to exposure using polar kinematics, in which the glass or glass-ceramic optics 35 are rotated about a rotational axis C' and the tactile or optical measuring point 49 10 is linearly movable in the direction of the rotational axis C' and transversely thereto. The measuring system is preferably capable of measuring surface deviations down to a dimensional accuracy tolerance of less than 5 µm. The measuring system is preferably capable of distinguishing between low-frequency (shape), medium-frequency (waviness), and short-frequency surface deviations (roughness).For some glass or glass-ceramic optics 35, for example, low-frequency surface deviations (absolute shape deviations) must be below one micrometer and medium-frequency surface deviations (waviness) below 300 nanometers, so that the measuring system must be able to measure the optical surfaces 37, 39 of the glass or glass-ceramic optics 35 with corresponding precision.

[0090] Fig. 6b shows how the correction system 25, 25' adapts the exposure profile 21, particularly at the optical surfaces 37, 39, for subsequently manufactured glass or glass-ceramic optics 35, such that the surface deviations that can then be measured thereon are reduced. In the already adjusted exposure profile 21' shown in Fig. 6b, the surface deviations from Fig. 6a are inverted in order to compensate for them. As a result, the geometry of the glass or glass-ceramic optic 35 iteratively approaches the target geometry 47, whereby one or two iterations may be sufficient to achieve a desired dimensional tolerance of less than 5 µm.It should be noted at this point that the correction system 25, 25' can preferably adapt not only the exposure profile 21, but, if necessary, also the path guidance and / or the local laser energy input density in order to distribute the laser pulses as homogeneously as possible in time and space on the optical surfaces 37, 39. Within the scope of the adaptations of the exposure profile 21, the correction system 25, 25' can also adapt the number, position, shape, and / or thickness of the etching channels 43a-d so that, during etching, every point on the optical surfaces 37, 39 is exposed to the etching medium for as long as possible.

[0091] Fig. 7a, b show exemplary arrangements of etching channels 43. Fig. 7a clearly shows that the etching channels 43 can preferably be arranged in a circular-cylindrical shell shape, distributed concentrically to the rotation axis C over the optical surface 37, 39. Fig. 7b clearly shows that the axial length of the etching channels 43, which corresponds to the penetration depth E at the corresponding point on the optical surface 37, 39, can vary over the optical surface 37, 39. The etching medium therefore has a different length of path through the etching channels 43 to the optical surface 37, 39. So that the areas of the optical surface 37, 39 with a smaller penetration depth E are not exposed to the etching medium for significantly longer than the areas of the optical surface 37, 39 with a greater penetration depth E, the etching channels 43 can be set more densely in areas of the optical surface 37, 39 with a greater penetration depth E and / or can be made thicker in the radial direction. In Fig.7b, for example, shows a first region 51 of the optical surface 37, 39 with a low penetration depth E and a correspondingly low density of etching channels 43. In a region 53 of the optical surface 37, 39 with a medium penetration depth E, the density of etching channels 43 is increased. In a region 55 of the optical surface 39 with a high penetration depth E, the density of etching channels 43 is highest. This at least partially compensates for the different path lengths for the etching medium to the optical surface 37, 39. Patent Attorneys Hemmer Lindfeld Frese INNP 3746 WO, 11 / 06 / 2024.

[0092] Fig. 8a,b illustrates that the continuous tracking of the penetration depth E of the laser focus 17 along the exposure profile 21 can lead to spherical aberration, which can change the caustic of the laser beam. However, an undesirable change in the caustic shape also changes the local laser energy input density, which in turn can lead to surface deviations after etching. In Fig. 8a, the laser focus 17 is strongly focused in the z-direction at a shallow penetration depth E. In Fig. 8b, the influence of spherical aberration is exaggerated at greater penetration depths, whereby the laser focus 17 widens in the z-direction and the local laser energy input density decreases accordingly.However, since this undesirable effect is easily predictable, the laser system 7 can adjust the focusing of the laser beam depending on the penetration depth E 15 of the laser focus 17 by appropriately adjusting the distance between the lenses 15a,b, such that the local laser energy input density at the laser focus 17 does not change due to changing the penetration depth E of the laser focus 17. Certain parameters of this dynamic adjustment of the focusing can be adjusted by the correction system if this allows measured surface deviations to be reduced.

[0093] Fig. 9 shows a schematic flow diagram according to an embodiment of the method disclosed herein for producing a glass or glass-ceramic optic 35 with a dimensional tolerance of less than 5 µm. At the beginning of a production series, in a first step 801, a first programmed exposure profile 21 and a programmed path guide 45 for the laser focus 17 are defined on the basis of a target geometry 47. The first exposure profile 21 defines the optical surfaces 37, 39 and the lateral surface 41 of the glass or glass-ceramic optic 35 to be produced from a first glass or glass-ceramic blank 3, as well as the etching channels 43. In a second step 803, the first glass or glass-ceramic blank 3 is clamped into the rotating system 5.This is followed by exposure 805 of the glass or glass-ceramic blank 3 along the programmed exposure profile 21 according to the programmed path guide 45. In a subsequent step, the exposed glass or glass-ceramic blank 3 is unclamped from the rotating system 5, and the exposed exposure profile 21 is etched out. In the subsequent step 809, the surface deviations, in particular on the optical surfaces 37, 39 of the etched glass or glass-ceramic optic 35, are measured. Since the first etched glass or glass-ceramic optic 35 probably does not yet meet the requirement of a dimensional tolerance below 5 µm, it can be disposed of as scrap after measurement 809.

[0094] For the second glass or glass-ceramic optic 35 to be produced in the series, steps 801a to 809a take place analogously to the first glass or glass-ceramic optic 35, with the difference that the exposure profile 21' and / or the path guidance 45 and / or the local laser energy input density are adjusted in step 801a based on the surface deviations of the first glass or glass-ceramic optic 35 measured in step 809 with respect to the target geometry 47. The exposure profile 21' can, for example, be inverted at the optical surfaces 37, 39 with respect to the measured surface deviations in order to compensate for the corresponding deviations.After the surface deviations of the second etched glass or glass-ceramic optic 35 compared to the target geometry 47 have been measured in step 809a, a decision can be made in an evaluation step 811 as to whether the glass or glass-ceramic optic 35 meets the requirements for a dimensional tolerance of less than 5 µm. If this is the case, the manufactured glass or glass-ceramic optic 35 can be provided in step 813. Assuming stable process conditions, the subsequently manufactured glass or glass-ceramic optics 35 can be manufactured with high productivity, with only the steps of clamping 803, exposure 805, and etching 807 being necessary.If the required dimensional accuracy has not yet been achieved, steps 801b to 809b can be performed analogously to steps 801a to 809a for a third glass or glass-ceramic optic 35 to be produced in the series. Patent Attorneys Hemmer Lindfeld Frese INNP 3746 WO, 11 / 06 / 2024 This can be repeated iteratively until the desired dimensional accuracy is achieved.

[0095] Figs. 10a-f show various shapes of optical surfaces 37, 39 of a glass or glass-ceramic optic 35, which can be inexpensively mass-produced for the first time with a dimensional tolerance of less than 5 µm using the method disclosed here. A major advantage of the exposure method disclosed here is that the glass or glass-ceramic optics 35 can be produced double-sided with optical surfaces 37, 39 on the front and back with a dimensional tolerance of less than 5 µm, since the glass or glass-ceramic blank 3 does not have to be removed from the rotating system 5 between the exposure of the optical surfaces 37, 39. Therefore, the optical surfaces 37, 39 shown in Figs. 10a-f are preferably arranged on the front and back of the glass or glass-ceramic optic 35, respectively. Fig. 10a shows an optical surface 37, 39 in the form of a spherical lens surface. Fig.10b shows an optical surface 37, 39 in the form of an aspherical lens surface. In particular, aspherical optical surfaces 37, 39 arranged on both sides of the glass or glass-ceramic optics 35 with a dimensional tolerance of less than 5 µm can be produced inexpensively using the exposure method disclosed herein. The glass or glass-ceramic optics 35 shown in Fig. 10a, b are rotationally symmetrical with respect to the axis of rotation C, which forms the optical axis of the glass or glass-ceramic optics 35. In Fig. 10c, d, non-rotationally symmetrical glass or glass-ceramic optics 35 are shown, wherein the glass-ceramic optics 35 in Fig. 10d additionally has microstructures on the optical surface 39. Fig. 10e shows an optical surface 39 in the form of a Fresnel converging lens. Fig. 10f shows an optical surface 39 in the form of a Fresnel lens. 30 .

[0096] Figs. 11a-c also show various glass or glass-ceramic optics 35, which, for the first time, can be inexpensively mass-produced using the process disclosed here with a dimensional tolerance of less than 5 µm. In this case, the optical surfaces 37, 39 serve not for light refraction, but for specular reflection. The optical surfaces 37, 39 can be coated with reflective coatings 59, 61 in a subsequent processing step. As shown in Fig. 11a, the optical surfaces 37, 39 can be shaped and arranged as desired to achieve a specific beam path of light 57 through the glass or glass-ceramic optics 35, wherein the light 57 is reflected inwards into the glass or glass-ceramic optics 35 at the specularly coated optical surfaces 37, 39 10.

[0097] Fig. 11b shows a glass or glass-ceramic optic 35 in the form of a monolithic, solid Cassegrain telescope, which, for the first time, can be inexpensively mass-produced with a dimensional tolerance of less than 5 µm using the method disclosed here. The rear optical surface 37 is arranged only in a central region around the optical axis C and is curved inwards. By means of a reflective coating 59, the rear optical surface 37 thus forms a mirror that is convexly curved into the material of the glass or glass-ceramic optic 35. The front optical surface 39, on the other hand, is arranged in an annular outer region of the glass or glass-ceramic optic 35 and is curved outwards. By means of a reflective coating 61, the front optical surface 39 forms a concave mirror that reflects into the material of the glass or glass-ceramic optic 35.If light 57 now enters the rear of the glass or glass-ceramic optics 35 radially 25 outside of the rear optical surface 37, the front optical surface 39 reflects the light 57 onto the rear optical surface 37, which ultimately reflects the light 57 forward through a central hole in the front optical surface 39. Such a Cassegrain telescope can be mass-produced inexpensively with high dimensional accuracy, making it suitable for satellite communications. Patent Attorneys Hemmer Lindfeld Frese INNP 3746 WO, 11 / 06 / 2024.

[0098] Fig. 11c shows a glass or glass-ceramic optic 35 in the form of a likewise monolithic Cassegrain telescope, which, using the method disclosed here, can be inexpensively mass-produced for the first time with a dimensional tolerance of less than 5 µm. In contrast to the solid embodiment of Fig. 11b, which has the disadvantage of a relatively high weight, the glass or glass-ceramic optic 35 here can form a monolithic hollow structure. When the exposure profile 21 is etched out, cores of the glass and glass-ceramic blank 3 are lost in the z-direction, so that the optical surfaces 37, 39 can be mirror-coated from the inside. The rear first optical surface 37 is retained here by support structures 63 defined by means of the exposure profile 21.When using the Cassegrain telescope, the light 57 does not penetrate the material of the glass or glass-ceramic optics 35 at all, but is merely reflected by the coated optical surfaces 37, 15, and 39, as shown. The advantage of the hollow structure according to Fig. 11c compared to the solid design according to Fig. 11b is its lower weight. This makes an embodiment according to Fig. 11c suitable for use on a satellite. The advantage of the solid design according to Fig. 11b, however, is greater stability. 20 .

[0099] List of reference symbols: 1 Irradiation device 3 Workpiece blank / glass or glass ceramic blank 5 Rotating system 7 Laser system 25 9 Laser beam 11 Laser beam source 13 Laser beam path guide 15a, b Lenses 17 Laser beam focus 30 19 Front side of the workpiece blank / glass or glass ceramic blank 21, 21' Irradiation profile / exposure profile Patentanwälte Hemmer Lindfeld Frese INNP 3746 WO, 11 / 06 / 2024 23 Control system 25, 25' Correction system 27 External computer / Cloud 29 Data interface 5 31 Back side of the workpiece blank / glass or glass ceramic blank 33 Lateral surface of the workpiece blank / glass or glass ceramic blank 35 Glass or glass ceramic optics 10 37 First optical surface 39 Second optical surface 41 Lateral surface of the glass or Glass ceramic optics 43,43a-d Etching channels 45 Path guide 15 47 Target geometry 49 Optical or tactile measuring point 51 First area of ​​the optical surface 53 Second area of ​​the optical surface 55 Third area of ​​the optical surface 20 57 Light 59 First reflective coating 61 Second reflective coating 63 Support structures E Penetration depth 25 r Radial distance C Rotational axis ^ Rotational speed ^ Rotational angle position ^^ Feed rate 30 801, 801a,b Defining / adapting the exposure profile 803, 803a,b Clamping the workpiece blank / glass or glass-ceramic blank Patentanwälte Hemmer Lindfeld Frese INNP 3746 WO, 11 / 06 / 2024 805, 805a,b Exposing the workpiece blank / glass or glass-ceramic blank 807, 807a,b Etching of the exposed exposure profile 809, 809a,b Measuring the surface deviations 5 811 Evaluating the surface deviations 813 Providing the glass or glass-ceramic optics A first range of radial distances B second range of radial distances C second range of radial distances 10 D second range of radial distances E second range of radial distances d spatial laser pulse spacing f laser pulse rate R, 1-5 Upper limits of the ranges of radial distances 15 Patent Attorneys Hemmer Lindfeld Frese INNP 3746 WO, 11 / 06 / 2024

Claims

Claims 1. Device (1) for laser irradiation of a workpiece blank (3) for producing a workpiece surface with a dimensional tolerance of less than 5 µm, the device (1) comprising: 5 - a rotating system (5) which is configured to clamp a workpiece blank (3) and to rotate it at an adjustable speed (^) about a rotational axis (C), - a laser system (7) which is configured to direct a laser beam (9) pulsed at an adjustable laser pulse rate (f) onto or into a workpiece blank (3) rotated by the rotating system (5) and to focus it such that a laser focus (17) is located at a variable radial distance (r) from the rotational axis (C) on or in the workpiece blank (3), - a control system (23) which is configured to change the laser focus (17) by changing the radial distance (r) of the laser focus (17) along a programmable irradiation profile (21),wherein the control system (23) is further configured to adapt the laser pulse rate (f) of the laser system (7) and the rotational speed (^) of the rotating system (5) as a function of the radial distance (r) of the laser focus (17), wherein in a first range (A) of radial distances (r) the laser pulse rate (f) of the laser system (7) is adapted to the radial distance (r) of the laser focus (17) at a preferably constant rotational speed (^) of the rotating system (5), and in at least a second range (B, C, D, E) of radial distances (r) the rotational speed (^) of the rotating system (5) is adapted to the radial distance (r) of the laser focus (17) at a preferably constant laser pulse rate (f) of the laser system (7).

2. Device (1) according to claim 1, wherein the control system (23) 30 is configured to control a spatial laser pulse spacing (d) on or in the workpiece blank (3) via the first and the at least atentanwälte Hemmer Lindfeld Frese INNP 3746 WO, 11 / 06 / 2024, to keep a second range (B, C, D, E) of radial distances (r) constant or to change it in a targeted manner.

3. Device (1) according to claim 1 or 2, wherein the control system (23) is configured to specifically change or adapt a laser energy per laser pulse of the laser system (7) depending on the radial distance (r) of the laser focus (17), the rotational speed (r) of the rotary system (8) and / or the laser pulse rate (f).

4. Device (1) according to one of the preceding claims, wherein the control system (23) is configured to increase or decrease the laser pulse rate (f) of the laser system (7) in the first range (A) of radial distances (r) proportionally to the radial distance (r) of the laser focus (17).Device (1) according to one of the preceding claims, wherein the control system (23) is configured to reduce the rotational speed (^) of the rotary system (5) in the at least one second range (B, C, D, E) of radial distances (r) inversely proportional to increasing radial distance (r) of the laser focus (17) or to increase it inversely proportional to decreasing radial distance (r) of the laser focus (17).

6. Device (1) according to one of the preceding claims, wherein the radial distances (r) in the first range (A) of radial distances (r) are smaller than in the at least one second range (B, C, D, E) of radial distances (r).

7. Device (1) according to one of the preceding claims, wherein a lower limit of the at least one second range (B, C, D, E) of radial distances (r) directly adjoins an upper limit of the first range (A) of radial distances (r). Attorneys at law Hemmer Lindfeld Frese INNP 3746 WO, 11 / 06 / 2024.

8. Device (1) according to one of the preceding claims, wherein the control system (23) is configured to abruptly change the laser pulse rate (f) at a transition between the first range (A) of radial distances (r) and the at least one second range (B, C, D, E) of radial distances (r) and to abruptly adjust the rotational speed (^) of the rotary system (5) so that a spatial laser pulse spacing (d) on or in the workpiece blank (3) remains constant or changes in a targeted manner at the transition between the first range (A) of radial distances (r) and the at least one second range (B, C, D, E) of radial distances (r).Device (1) according to one of the preceding claims, wherein the control system (23) is configured to operate the laser system (7) in the first range (A) of radial distances (r) in a pulse-on-demand mode and to operate the laser system (7) in the at least one second range (B, C, D, E) of radial distances (r) with an integer part of a reference laser pulse rate. 10.Device (1) according to one of the preceding claims, wherein there are a plurality of adjacent second regions (B, C, D, E) of radial distances (r) and the control system (23) is configured to abruptly switch the laser pulse rate (f) from one integer part of a reference laser pulse rate to another integer part of a reference laser pulse rate at the transition between the second regions (B, C, D, E) of radial distances (r) and to abruptly adjust the rotational speed (^) of the rotary system (5) so that a spatial laser pulse distance (d) on or in the workpiece blank (3) remains constant or changes in a targeted manner at the transition between the second regions (B, C, D, E) of radial distances (r). Attorneys at law Hemmer Lindfeld Frese INNP 3746 WO, 11 / 06 / 2024.

11. Device (1) according to one of the preceding claims for exposing the workpiece blank (3) in the form of a glass or glass-ceramic blank (3) within the framework of a selective laser etching process, LSE, wherein the laser system (7) is configured to direct the pulsed laser beam (9) into the glass or glass-ceramic blank (3) rotated by the rotating system (5) and to focus it such that a laser focus (17) with a local laser energy input density lies at a variable penetration depth (E) in the direction of the rotation axis (C) and at a variable radial distance (r) to the rotation axis (C) within the glass or glass-ceramic blank (3) in order to effect material changes in the glass or glass-ceramic blank (3) by the laser focus (17), and wherein the control system (23) is configured toto control the laser focus (17) with a programmable path guide (45) along the programmable irradiation profile (21) within the glass or glass-ceramic blank (3) by changing the penetration depth (E) and the radial distance (r) of the laser focus (17) in the turned glass or glass-ceramic blank (3), and wherein the device (1) further comprises a correction system (25, 25'), wherein the correction system (25, 25') is designed to adapt the irradiation profile (21) and / or the path guide (45) and / or the local laser energy input density for a glass or glass-ceramic blank (3) to be subsequently exposed such that surface deviations which occur on the glass or glass-ceramic optics (35) after etching out the irradiation profile (21) with respect to a target geometry (47) are measurable, are reduced in a subsequently manufactured glass or glass-ceramic optic (35).

12. Device (1) according to one of the preceding claims,30 wherein the laser system (7) is further configured to adjust the focusing of the laser beam (9) depending on the penetration depth (E) of the laser focus (17) such that the local laser energy input atentanwälte Hemmer Lindfeld Frese INNP 3746 WO, 11 / 06 / 2024, density at the laser focus (17) is not changed by changing the penetration depth (E) of the laser focus (17).

13. Device (1) according to one of the preceding claims, wherein the laser system (7) has at least two lenses (15a, b) and is configured to change the penetration depth (E) of the laser focus (17) by changing a distance between the at least two lenses (15a, b).

14. Device (1) according to one of the preceding claims, wherein the control system (23) is further configured to adapt a rotational speed (^) of the rotary system (5) and / or a laser pulse rate (f) of the laser system (7) as a function of the radial distance (r) of the laser focus (17) from the rotation axis (C) such that the local laser energy input density along a path guide (45) of the irradiation profile (21) is constant or changes in a targeted manner.Device (1) according to one of the preceding claims, wherein the rotation system (5) is movable transversely to the axis of rotation (C) and the control system (23) is configured to control the radial distance (r) of the laser focus (17) by moving the rotation system (5) transversely to the axis of rotation (C).

16. Device (1) according to one of the preceding claims, the laser system (7) is configured to provide the pulsed laser beam (9) with a variable laser pulse energy per laser pulse, wherein the control system (23) is configured to control the local laser energy input density by changing the laser pulse rate (f) and / or the laser pulse energy per laser pulse. Attorneys at law Hemmer Lindfeld Frese INNP 3746 WO, 11 / 06 / 2024.

17. The device (1) according to one of the preceding claims, wherein the irradiation profile (21) defines an optical surface (37, 39) of the glass or glass-ceramic optic (35).

18. The device (1) according to claim 17, wherein the irradiation profile (21) defines at least one etching channel (43, 43a-c) extending from the optical surface (37, 39) to a front or rear side (19, 31) of the glass or glass-ceramic blank (3).Device (1) according to one of the preceding claims, wherein the irradiation profile (21) defines a first optical surface (37) of the glass or glass-ceramic optics (35) and a second optical surface (39) of the glass or glass-ceramic optics (35), wherein the first optical surface (37) is further away from the laser system (7) in the direction of the axis of rotation (C) than the second optical surface (39), wherein a path guide (45) along the irradiation profile (21) is programmed such that the first optical surface (37) is traversed by the laser focus (17) before the second optical surface (39).Device (1) according to claim 19, wherein the irradiation profile (21) defines at least one first etching channel (43a,b) and at least one second etching channel (43c,d), wherein the at least one first etching channel (43a,b) extends from the first optical surface (37) to a rear side (31) of the glass or glass-ceramic blank (3) facing away from the laser system (7), wherein the at least one second etching channel (43c,d) extends from the second optical surface (39) to a front side (19) of the glass or glass-ceramic blank (3) facing the laser system (7).

21. Device (1) according to one of the preceding claims, further comprising a measuring system for measuring surface deviations. Attorneys at Law Hemmer Lindfeld Frese INNP 3746 WO, 11 / 06 / 2024. with respect to the target geometry (47) after etching the irradiation profile (21), wherein the measuring system is configured to guide a tactile or optical measuring point (49) over an optical surface (37, 39) of a glass or glass-ceramic optic (35) clamped and rotated in the rotation system (5).

22. Device (1) according to one of the preceding claims, further comprising a data interface (29) for receiving data on surface deviations with respect to the target geometry (47) after etching the irradiation profile (21), which were measured by means of an external measuring system.

23. Device (1) according to one of claims 11 to 22, wherein the correction system (25, 25') is integrated into the control system (23) or is installed on a computer (27) separate from the control system (23). 24.Method (1) for laser irradiation of a workpiece blank (3) for producing a workpiece surface with a dimensional tolerance of less than 5 µm, the method comprising: - rotating a workpiece blank (3) clamped in a rotating system (5) at an adjustable speed (^) about a rotational axis (C), - directing and focusing a laser beam (9) pulsed at an adjustable laser pulse rate (f) into or onto the rotated workpiece blank (3) by means of a laser system (7), such that a laser focus (17) is located at a variable radial distance (r) from the rotational axis (C) on or in the workpiece blank (3), - controlling the laser focus (17) along a programmable irradiation profile (21) by changing the radial distance (r) of the laser focus (17), attorneys at law Hemmer Lindfeld Frese INNP 3746 WO, 11 / 06 / 2024. - adjusting the laser pulse rate (f) of the laser system (7) and the rotational speed (^) of the rotary system (5) as a function of the radial distance (r) of the laser focus (17), wherein in a first range (A) of radial distances (r), the laser pulse rate (f) of the laser system (7) is adjusted to the radial distance (r) of the laser focus (17) at a preferably constant rotational speed (^) of the rotary system (5), and in at least one second range (B, C, D, E) of radial distances (r), the rotational speed (^) of the rotary system (5) is adjusted to the radial distance (r) of the laser focus (17) at a preferably constant laser pulse rate (f) of the laser system (7).

25. The method according to claim 24, wherein a spatial laser pulse distance (d) on or in the workpiece blank (3) is kept constant or specifically changed over the first and the at least one second range (B, C, D, E) of radial distances (r). 26.Method according to claim 24 or 25, wherein in the first range (A) of radial distances (r) the laser pulse rate (f) of the laser system (7) is increased or decreased proportionally with the radial distance (r) of the laser focus (17).

27. Method according to one of claims 24 to 26, wherein in the at least one second range (B, C, D, E) of radial distances (r) the rotational speed (^) of the rotary system (5) is decreased inversely with increasing radial distance (r) of the laser focus (17) or increased inversely with decreasing radial distance (r) of the laser focus (17).

28. Method according to one of claims 24 to 27, wherein the radial distances (r) in the first range (A) of radial distances (r) are smaller than in the at least one second range (B, C, D, E) of radial distances (r). Attorneys at Law Hemmer Lindfeld Frese INNP 3746 WO, 11 / 06 / 2024.

29. The method according to any one of claims 24 to 28, wherein a lower limit of the at least one second range (B, C, D, E) of radial distances (r) directly adjoins an upper limit of the first range (A) of radial distances (r).

30. The method according to any one of claims 24 to 29, wherein the laser pulse rate (f) is changed abruptly at a transition between the first range (A) of radial distances (r) and the at least one second range (B, C, D, E) of radial distances (r), and the rotational speed (^) of the rotary system (5) is adjusted abruptly, so that a spatial laser pulse spacing (d) on or in the workpiece blank (3) remains constant or changes in a targeted manner at the transition between the first range (A) of radial distances (r) and the at least one second range (B, C, D, E) of radial distances (r). 31.Method according to one of claims 24 to 30, wherein the laser system (7) is operated in a pulse-on-demand mode in the first range (A) of radial distances (r) and the laser system (7) is operated in the at least one second range (B, C, D, E) of radial distances (r) with an integer part of a reference laser pulse rate.

32. Method according to one of claims 24 to 31, wherein there are a plurality of adjacent second regions (B, C, D, E) of radial distances (r) and the laser pulse rate (f) is switched abruptly from one integer part of a reference laser pulse rate to another integer part of a reference laser pulse rate at the transition between the second regions (B, C, D, E) of radial distances (r) and the rotational speed (^) of the rotary system (5) is adjusted abruptly so that a spatial laser pulse distance (d) on or in the workpiece blank (3) at the transition between the atentanwälte Hemmer Lindfeld Frese INNP 3746 WO, 11 / 06 / 2024.second areas (B, C, D, E) of radial distances (r) remains constant or changes in a targeted manner.

33. Method according to one of claims 24 to 32 for exposing the workpiece blank (3) in the form of a glass or glass-ceramic blank (3) within the scope of a selective laser etching process, LSE, wherein the laser focus (17) is directed and focused such that it lies with a local laser energy input density at a variable penetration depth (E) in the direction of the rotation axis (C) and at a variable radial distance (r) from the rotation axis (C) within the glass or glass-ceramic blank (3) in order to effect material changes in the glass or glass-ceramic blank (3) through the laser focus (17),and wherein the laser focus (17) is guided with a programmable path guide (45) along the programmable irradiation profile (21) within the glass or glass-ceramic blank (3) by changing the penetration depth (E) and the radial distance (r) of the laser focus (17) in the turned glass or glass-ceramic blank (3), the method further comprising: - adapting (801a, b) the irradiation profile (21) and / or the path guide (45) and / or the local laser energy input density for a glass or glass-ceramic blank (3) to be subsequently exposed, so that surface deviations measured on the glass or glass-ceramic optic (35) after etching out the irradiation profile (21) with respect to a desired geometry (47) are reduced in a glass or glass-ceramic optic (35) to be subsequently produced.

34. Method according to claim 32,The method is repeated iteratively until the measured surface deviations of the glass or glass-ceramic optics (35) are below a dimensional tolerance of 5 µm. Attorneys at law Hemmer Lindfeld Frese INNP 3746 WO, 11 / 06 / 2024, 35. The method according to any one of claims 24 to 34, wherein the focusing of the laser beam (9) is adjusted depending on the penetration depth (E) of the laser focus (17) such that the local laser energy input density at the laser focus (17) does not change by changing the penetration depth (E) of the laser focus (17).

36. The method according to any one of claims 24 to 35, wherein the penetration depth (E) of the laser focus (17) is changed by changing a distance between at least two lenses (15a, b) of the laser system (7).

37. Method according to one of claims 24 to 36, wherein a rotational speed (^) of the rotation system (5) and / or a laser pulse rate (f) of the laser system (7) is adjusted as a function of the radial distance (r) of the laser focus (17) from the rotation axis (C) such that the local laser energy input density along a path guide (45) along the irradiation profile (21) is constant or changes in a targeted manner. 38.Method according to one of claims 24 to 37, wherein the radial distance (r) of the laser focus (17) is controlled by moving the rotation system (5) transversely to the rotation axis (C).

39. Method according to one of claims 24 to 38, wherein the irradiation profile (21) defines an optical surface (37, 39) of the glass or glass-ceramic optics (35).

40. Method according to claim 39, wherein the irradiation profile (21) defines at least one etching channel (43, 43a-d) extending from the optical surface (37, 39) of the glass or glass-ceramic optics (35) to a front or rear side (19, 31) of the glass or glass-ceramic blank (3). Attorneys at law Hemmer Lindfeld Frese INNP 3746 WO, 11 / 06 / 2024.

41. Method according to one of claims 24 to 40, wherein the irradiation profile (21) defines a first optical surface (37) of the glass or glass-ceramic optics (35) and a second optical surface (39) of the glass or glass-ceramic optics (35), wherein the first optical surface (37) is further away from the laser system (7) in the direction of the axis of rotation (C) than the second optical surface (39), wherein a path guide (45) along the irradiation profile (21) is programmed such that the first optical surface (37) is traversed by the laser focus (17) before the second optical surface (39).Method according to claim 41, wherein the irradiation profile (21) defines at least one first etching channel (43a,b) and at least one second etching channel (43c,d), wherein the at least one first etching channel (43a,b) extends from the first optical surface (37) to a rear side (31) of the glass or glass-ceramic blank (3) facing away from the laser system (7), wherein the at least one second etching channel (43c,d) extends from the second optical surface (39) to a front side (19) of the glass or glass-ceramic blank (3) facing the laser system (7), wherein the path guide (45) along the irradiation profile (21) is programmed such that the at least one first etching channel (43a,b) is temporally before the first optical surface (37) and the at least one second etching channel (43c,d) is traversed by the laser focus (17) after the second optical surface (39). 25 43.Method for producing a glass or glass-ceramic optic with a dimensional tolerance of less than 5 µm by means of selective laser etching, LSE, the method comprising: - irradiating (801-805) a glass or glass-ceramic blank (3) according to one of claims 23 to 41, 30 - etching out (807) the irradiation profile (21), and attorneys at law Hemmer Lindfeld Frese INNP 3746 WO, 11 / 06 / 2024. - Measuring (809) the surface deviations of the glass or glass-ceramic optic (35) after etching (807) the irradiation profile (21) with respect to a target geometry (47).

44. The method according to claim 43, wherein the glass or glass-ceramic blank (3) is removed from the rotating system (5) for etching (807) the irradiation profile (21), and the etched glass or glass-ceramic optic (35) is clamped back into the rotating system (5) for measuring (807) the surface deviations, wherein a tactile or optical measuring point (49) is guided over an optical surface (37, 39) of the glass or glass-ceramic optic (35) clamped and rotated in the rotating system (5). 45.Method according to claim 43, wherein the glass or glass-ceramic blank (3) is unclamped from the rotating system (5) for the etching (807) of the irradiation profile (21), and the surface deviations are measured in a measuring system, wherein data about the surface deviations are provided by the measuring system for the adjustment (801a, b) of the irradiation profile (21) and / or the path guidance (45) and / or the local laser energy input density.

46. Method according to one of claims 43 to 45, wherein the surface deviations of the glass or glass-ceramic optics (35) are at least partially corrected by laser ablation on an optical surface (37, 39) of the glass or glass-ceramic optics (35) clamped and rotated in the rotating system (5).

47. A glass or glass-ceramic optic (35) manufactured using a method according to any one of claims 24 to 46 with a dimensional tolerance of less than 5 µm. Attorneys at law Hemmer Lindfeld Frese INNP 3746 WO, 11 / 06 / 2024.

48. Glass or glass-ceramic optics (35) according to claim 47, wherein the glass or glass-ceramic optics (35) are designed rotationally symmetrically to the axis of rotation (C), in particular in the form of a single-sided or double-sided aspherical lens.

49. Glass or glass-ceramic optics (35) according to claim 47, wherein the glass or glass-ceramic optics (35) are designed non-rotationally symmetrically to the axis of rotation (C), in particular in the form of a contact lens, a spectacle lens, an exposure optic, a mirror surface to be coated, or a microstructured optic, wherein the glass or glass-ceramic optics (35) have an optical surface (37, 39) on one or both sides.

50. Glass or glass-ceramic optics (35) according to one of claims 47 to 49, wherein the glass or glass-ceramic optics (35) is designed in the form of a Fresnel lens and / or with a blazed grating or a diffractive surface structure. 51.Glass or glass-ceramic optics (35) according to one of claims 47 to 50, wherein the glass or glass-ceramic optics (35) has an optical front side (39) and an optical back side (37), wherein at least one surface region of the optical front side (39) and / or the optical back side (37) is coated to be reflecting, preferably inwardly reflecting.

52. Glass or glass-ceramic optics (35) according to claim 51, wherein the at least one reflectingly coated surface region of the optical front side (39) is convexly curved when viewed from the inside and / or the at least one reflectingly coated surface region of the optical back side (37) is concavely curved when viewed from the inside. Attorneys at law Hemmer Lindfeld Frese INNP 3746 WO, 11 / 06 / 2024.

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