DE102011082627A1 - Device for guiding light beam, comprises angular adjustable optical component, measuring light beam, detector, plane-parallel plate having two plane-parallel surfaces, wedge plate, actuator, focusing optics, and second plane-parallel plate - Google Patents

Abstract

The device comprises: an angular adjustable optical component, which is rotably driven, arranged and formed to a rotational axis (15) so that an incident light beam parallely passes to the rotational axis through the adjustable optical component and as well as is parallely moved and/or deflected as a result of refraction so that the light beam describes circle path in a plane due to the refraction through the optical component and its rotation transverse to the rotational axis, where the optical component comprises a reflecting surface (126). The device comprises: an angular adjustable optical component, which is rotably driven, arranged and formed to a rotational axis (15) so that an incident light beam parallely passes to the rotational axis through the adjustable optical component and as well as is parallely moved and/or deflected as a result of refraction so that the light beam describes circle path in a plane due to the refraction through the optical component and its rotation transverse to the rotational axis, where the optical component comprises a reflecting surface (126), which is held in such a way that a tilt angle (127) of the optical component is adjusted to a tilting axis transversely arranged to the rotational axis; a device for determining the tilt angle having a light source (310), which is arranged adjacent to the optical component; a measuring light beam transferring in direction of the optical component in such a way that the measuring light beam is reflected during a part of a complete revolution of an optical element by the reflecting surface of the optical component; a detector, which is arranged in such a way that the reflected measuring light beam strikes on the detector; a plane-parallel plate having two plane-parallel surfaces; and a wedge plate, which comprises a first optical element (140) and a second optical element and two plane surfaces as end faces. The optical component is the plane-parallel plate, and the tilt angle is an angle of a surface normal of the plane-parallel surface relative to the rotational axis. The optical elements comprise a complementary spherical surface from which the spherical surface forms a concave surface of the first optical element and an other spherical surface forms a convex surface of the second optical element. The concave surface and the convex surface possess a same radius of curvature in such a way that the planar surfaces are proceeded than the respective spherical surface of the surfaces facing towards the respective optical element optionally in plane-parallel or a wedge angle relative to shift each other along the spherical surfaces facing towards one another. The optical component is a first optical element or a second optical element, where the tilt angle is the angle of the surface normal of the end faces of the first- and/or second- optical elements relative to the rotational axis. The first- and second- optical elements are the optical components and are provided with the two measuring light beams and the detectors. The wedge plate is arranged in a propagation direction of the light beam after the plane-parallel plate. The detector: is formed in such a way that it detects a position of the reflected measuring light; and comprises detection elements arranged in a line. The device further comprises: a device for calculating the tilt angle as a function of the position of incidence of the reflected measuring light beam; an actuator, which is adjusted to the tilt angle and/or a controller that is adapted to drive the actuator so that the reflected measuring light beam strikes in a desired position on the detector; focusing optics, which are arranged in the propagation direction of the light beam before the adjustable optical component; and a second plane-parallel plate, which is arranged in the propagation direction of the light beam after the adjustable optical component. The reflecting surface of the adjustable optical component: has a side surface of the optical components that is arranged so that the measuring light beam temporarily meets during the operation of the device on the side surface and is reflected from the side surface as a function of the tilt angle; and is partially, reflectively coated. The controller is proportional controller, a proportional-integral controller, a proportional-integral-derivative controller or a proportional-derivative controller.

Description

The invention relates to a device for guiding a light beam according to the preamble of claim 1.

Such devices for guiding a light beam are commonly used to process solid materials by means of a laser beam. The laser beam, at the point at which it impinges on the material, provides for a selective energy supply, which leads to the local decomposition of the material. In this way, for example, a part of a workpiece can be separated or the surface can be processed. Since the processing takes place in each case at the point where the light beam impinges, an exact guidance of the light beam is of great importance.

The document PCT / EP2008 / 053042 shows a device for guiding a light beam with a plane-parallel plate, which can be driven to rotate about a rotation axis, and which has two plane-parallel surfaces. The plane-parallel plate is held such that an acute tilt angle of a surface normal of the plane-parallel surfaces is assumed relative to the axis of rotation. Such an oblique arrangement of the plane-parallel plate relative to the axis of rotation, which in this case is equal to the optical axis of the device, ensures that the incident light beam is offset in parallel by means of the plane-parallel plate. By rotating the plane-parallel plate, the light beam can thus be guided on a circular path, whereby a cylindrical part can be cut out of the workpiece.

It would be desirable to be able to measure the tilt angle during operation of the device.

This is achieved according to the invention by the subject matter of claim 1. Advantageous embodiments of the invention are contained in the subclaims.

According to the invention, an apparatus for guiding a light beam is provided, namely with an angle-adjustable optical component which is rotatably drivable about a rotation axis. The angle-adjustable optical component is arranged and designed such that a light beam incident parallel to the axis of rotation passes through the angle-adjustable optical component and is parallel offset and / or deflected as a result of refraction, so that the light beam is due to the refraction by the angle-adjustable optical component and its rotation describes a circular path in a plane transverse to the axis of rotation. The angle-adjustable optical component is thus a Strahlversatzeinrichtung. The angle-adjustable optical component further has at least one reflection surface and is held such that a tilt angle of the angle-adjustable optical component is adjustable about a tilt axis arranged transversely to the axis of rotation. About the tilt angle of the parallel offset or the deflection of a passing through the angle-adjustable optical component light beam is adjustable. In addition, a device for determining the tilt angle is present, so that, for example, a certain parallel offset or a specific deflection can be controlled or continuously monitored.

The reflection surface is preferably a side surface of the respective angle-adjustable optical component and preferably has a surface normal, which is aligned transversely to the light beam.

According to a preferred embodiment, the angle-adjustable optical component is a plane-parallel plate, which has two plane-parallel surfaces, which are aligned transversely to the light beam. The tilt angle in this case is an angle of a surface normal of the plane-parallel surfaces relative to the rotation axis.

Part of the device for determining the tilt angle is a light source, which is arranged adjacent to the angle-adjustable optical component and emits a measurement light beam in the direction of the angle-adjustable optical component such that the measurement light beam during at least part of a complete revolution of the angle-adjustable optical component of the reflection surface of the angle-adjustable optical component is reflected. Another part of the device is a detector which is arranged such that the reflected measuring light beam impinges on him.

The angle-adjustable optical component or the plane-parallel plate can be made of plastic, glass or another transparent material. Typically, a plane-parallel plate is circular, with plane-parallel surfaces formed by two opposing circular surfaces, while the side surface is an annular surface between these two plane-parallel surfaces.

The axis of rotation of the device is preferably parallel, more preferably identical to an optical axis of the device, which is the axis on which the light beam is preferably incident.

By means of a plane-parallel plate whose surface normal has a tilt angle relative to the axis of rotation, and thus according to the typical embodiment also relative to the optical axis, the incident light beam can be offset in parallel. The direction of the parallel offset is dependent on the current position of the plane-parallel plate. If this is rotated, the light beam can thus be guided on a circular path.

The drive of the angle-adjustable optical component is preferably carried out by means of an electric motor, which transmits via a drive means, such as a gear, a belt or a chain, a rotary motion to the device. The angle-adjustable optical component can for this purpose preferably be installed in a holder, wherein the holder is driven in rotation, for example by a hollow shaft drive. However, other drive mechanisms are conceivable.

The tilt angle relative to the axis of rotation is preferably also during operation, that is, while the angle-adjustable optical component is driven in rotation, adjustable. For this purpose, electrical and / or mechanical means may be provided.

Alternatively, however, the device may also be designed such that the tilt angle can only be adjusted when the device is at rest.

With the aid of the device for determining the tilt angle, the tilt angle can also be determined during operation, that is, while the angle-adjustable optical component is driven in rotation. This makes it possible not only continuously to check the tilt angle, but also to monitor the change in any intended changes in the tilt angle during operation and / or to provide a regulation of the tilt angle.

The light source arranged adjacent to the angle-adjustable optical component emits light during operation, which serves as measuring light beam. Typically, a laser is used for this purpose. However, ordinary light with a particularly distant focus comes for this purpose into consideration. The light source may be connected such that it generally emits light when the device is in operation, for example, when the angle-adjustable optical component is driven in rotation. Alternatively, however, the light source can also be switched on only at certain times, for example when a check of the tilt angle is to be made.

The measuring light beam should be emitted in such a way that it strikes the side surface of the angle-adjustable optical component, at least during part of a complete revolution of the angle-adjustable optical component. If the angle-adjustable optical component is surrounded by a holder, the holder can have an opening at least at a corresponding point or be made transparent. Instead of the measuring beam reflecting side surfaces of the angle-adjustable optical component and a corresponding reflective surface may be provided on the holder, in particular if the holder is a kind version for the angle-adjustable optical component, which is tilted together with the angle-adjustable optical component to adjust the tilt angle.

The detector should at least be designed in such a way that it detects whether or not the light beam strikes it. It can also be designed to measure the intensity of the incident light beam. The detector typically outputs an electrical signal indicative of an impact of the light beam. Thus photodiodes, avalanche photodiodes, photoresistors, charge-coupled devices (CCDs), photomultiplier tubes or silicon photomultipliers (SiPM) can be used for such a detector.

Preferably, the device is designed such that the propagation direction of the reflected measuring light beam is dependent on the tilt angle. Thus, the measuring light beam maps the tilt angle to a technically measurable size. Since the geometric parameters of the device are known, it is possible to exactly calculate back from the impact of the measuring light beam at a specific location on the tilt angle.

In a preferred embodiment, the detector is designed such that it can detect the position of the impact of the reflected measuring light beam. For this purpose, the detector may be formed, for example, with a plurality of identical or different detection elements. These detection elements are distributed over the total area of the detector. Thus, the detector can not only provide a signal indicating whether the measuring light beam is incident at all, but can also indicate at which point of the detector the measuring light beam impinges. This makes it possible to detect with a fixed detector a certain range of tilt angles and associated points of impact of the measuring light beam immediately.

Alternatively, a detector, which has only one detection element, can be arranged to be displaceable, so that the position of the light beam can be determined by the fact that the detector as long as shifted until the measuring light beam impinges on him and / or maximum intensity is achieved.

If the detector is designed such that it can detect the position of the impact of the reflected measuring light beam, the detector preferably has a plurality of detection elements arranged in a row. In this case, the device is preferably designed such that the measuring light beam sweeps once over the detection elements arranged in a row during one rotation of the angle-adjustable optical component. This makes it possible to carry out a measurement of the position of the measurement light beam, and thus also of the tilt angle, per revolution. Due to the usually high speeds with which the angle-adjustable optical component is rotated, this is often sufficient.

Preferably, the device further comprises means for calculating the tilt angle in dependence on the position of the impact of the reflected measuring light beam. With the aid of such a device, the tilt angle can be determined directly from a signal which indicates which of the detection elements the measurement light beam impinges on or impinges on. The means for calculating the tilt angle typically uses the geometrical parameters of the device for this purpose, from which it is known from where the measuring light beam comes from, where it is reflected and where it impinges on the detector. The device can be embodied for example in the form of a microprocessor, an integrated circuit, hard-wired electronics or the like.

Preferably, the reflection surface of the angle-adjustable optical component is coated at least partially reflective. Particularly preferably, the coating is located at least at the location of the angle-adjustable optical component, at which the measuring light beam is to be reflected in the direction of the detector. The reflective coating results in a higher proportion of the incident measuring light beam being reflected in the direction of the detector, so that the detection of the measuring light beam is improved. Such a coating may for example consist of aluminum, silver, polished silicon or a dielectric layer.

In a preferred embodiment, the device further comprises an actuator which can adjust the tilt angle. The actuator is preferably designed such that it can change the tilt angle by an electrical or mechanical signal during operation of the device. For example, the actuator may have a servomotor or an electrically operated threaded rod. With the aid of the actuator, it is firstly possible to make an adjustment of the tilt angle to the desired value in the case of deviations of the tilt angle from a predefined setpoint detected by the detector. In addition, the actuator can also be used to change the setpoint of the tilt angle during operation to another value. This is relevant, for example, when a parallel offset of the light beam is to be changed to a different value during operation of the device, without bringing a plane-parallel plate to a standstill.

The device with such an actuator also preferably has a control, which controls the actuator such that the reflected measuring light beam impinges in a desired position on the detector. As a result, the desired position can be entered by an operator of the device, the controller ensures their compliance. If, during operation, deviations of an actual position of the measurement light beam from the desired position occur, the controller can adjust the tilt angle with the aid of the actuator. Since a desired position on the detector due to the predetermined geometry of the device corresponds to a desired value of the tilt angle, it is thus also possible for a user to specify a desired value of the tilt angle. The specification of a desired position of the measuring light beam on the detector and the specification of a desired value for the tilt angle can thus be regarded as equivalent.

The controller is preferably a proportional (P) controller, a proportional-integral (PI) controller, a proportional-integral-derivative (PID) controller, or a proportional-differential (PD) controller. The proportional component of such a controller supplies an immediate step response in the event of a deviation between the setpoint and the actual value. However, the pure use of a proportional component is known to result in a control deviation also in the static case. If this is known, this can be compensated by the fact that the target value is adjusted accordingly. With the aid of the integral component, the controller is supplemented by an integral variable, which can rule out the remaining control deviation. However, this happens only after a certain time. The differential component ensures that in the case of particularly abrupt changes in the actual value (assuming a constant desired value) or even in the case of instantaneous changes in the desired value, an immediately effective controlled variable is generated which accelerates the setting of the actual value.

According to a preferred embodiment, the device further comprises a focusing optics. This can be formed for example by a converging lens. It serves to adjust the focus of the light beam, for example, such that the Focus coincides with the surface of a workpiece to be machined. Thus, a particularly intensive local energy release can be achieved on a particularly small area. Alternatively, however, the focus can also be adjusted such that the diameter of the beam is greater when hitting the workpiece. Then the energy of the light beam is distributed over a larger area.

The focusing optics is preferably arranged in the propagation direction of the light beam in front of the angle-adjustable optical component, that is to say in such a way that the light beam initially strikes the focusing optics before it strikes the angle-adjustable optical component, for example the plane-parallel plate. Particularly preferably, the focusing optics is that optical element of the device, to which the incident light beam strikes first. This makes it possible to adjust the focus of the light beam before the light beam is further changed by other optical elements.

In a preferred embodiment, the device further comprises a second plane-parallel plate. The second plane-parallel plate can preferably be driven in rotation independently of a (first) plane-parallel plate, if one is present. This makes it possible to rotate the two plane-parallel plates at different speeds. Thus, for example, a circular spiral path of the light beam can be achieved on the workpiece, whereby a cylindrical piece can be cut out of the workpiece and thereby the cutting width can be adjusted. The statements made with respect to the (first) plane-parallel plate are also applicable to the second plane-parallel plate. In particular, the device may have a device for determining a tilt angle of the second plane-parallel plate. The tilt angle of the second plane-parallel plate is the angle between a surface normal of plane-parallel surfaces of the second plane-parallel plate relative to the axis of rotation. Also, the tilt angle of the second plane-parallel plate can be adjusted relative to the axis of rotation. The options, possibilities and advantages mentioned in relation to the (first) plane-parallel plate also apply to the second plane-parallel plate.

The second plane-parallel plate, viewed in the propagation direction of the light beam, is preferably arranged behind the angle-adjustable optical component or behind a (first) plane-parallel plate, and preferably has a smaller thickness.

• – einander zugewandte, komplementäre sphärische Oberflächen aufweisen, von denen die eine sphärische Oberfläche eine konkave Fläche des ersten optischen Elementes bildet und die andere sphärische Oberfläche eine konvexe Fläche des zweiten optischen Elementes bildet und die konkave Fläche und die konvexe Fläche den gleichen Krümmungsradius besitzen, und
• – derart relativ zueinander entlang der einander zugewandten sphärischen Oberflächen zu verschieben sind, dass die planen Oberflächen als der jeweiligen sphärischen Oberfläche eines jeweiligen optischen Elementes abgewandte Oberflächen wahlweise planparallel oder in einem Keilwinkel zueinander verlaufen.

According to a preferred embodiment, the device additionally or alternatively has an optical component which can act both as a plane-parallel plate and as a wedge plate and for simplicity's sake is hereinafter referred to as a wedge plate, even if it is also a plane-parallel plate. The wedge plate is formed from a first and a second optical element, and has two planar surfaces as end faces, wherein the optical elements of the wedge plate

• - have mutually facing, complementary spherical surfaces, of which one spherical surface forms a concave surface of the first optical element and the other spherical surface forms a convex surface of the second optical element and the concave surface and the convex surface have the same radius of curvature, and
• - To move relative to each other along the mutually facing spherical surfaces, that the flat surfaces as the respective spherical surface of a respective optical element facing away from surfaces either plane-parallel or at a wedge angle to each other.

With the aid of such a wedge plate, an angle of the light beam when exiting the device relative to the incoming light beam can be adjusted. The wedge plate has the advantage that it retains a substantially rotationally symmetric mass distribution even when setting a wedge angle and thus does not lead to an imbalance of the device.

The wedge plate is preferably arranged in the propagation direction of the light beam behind a plane-parallel plate. If the device has a second plane-parallel plate, the wedge plate is preferably arranged between the plane-parallel plate and the second plane-parallel plate.

According to one embodiment, the angle-adjustable optical component is the first optical element. The tilt angle in this case is an angle of a surface normal of the end face of the first optical element relative to the rotation axis.

According to another embodiment, the angle-adjustable optical component is the second optical element. The tilt angle in this case is an angle of a surface normal of the end face of the second optical element relative to the rotation axis.

According to further preferred embodiments, the device may also have a plurality of angle-adjustable optical components, for each of which an associated measuring light beam and in each case a detector and possibly also an actuator and a controller are provided. In the case of the two complementary optical elements having wedge plate, for example, both optical elements each have an angle-adjustable optical Be component. Further advantages and features of the invention will become apparent from the description of an embodiment of the invention with reference to 1 ,

This shows a device 10 for guiding a light beam 20 on a workpiece 30 , The device is divided into an upper part 100 and a lower part 200 , The upper part 100 has a condenser lens 110 on, which serves as a focusing optics. The upper part 100 further has a plane-parallel plate 120 on, which in the propagation direction of the light beam to the convergent lens 110 is arranged. In addition, the upper part 100 a wedge plate 130 on which is a concave part 140 and a convex part 150 consists. The wedge plate 130 is in the propagation direction of the light beam after the plane-parallel plate 120 arranged.

The condenser lens 110 , the plane-parallel plate 120 and the wedge plate 130 be from a holder 160 held. The holder 160 is rotationally symmetrical and rotatably mounted. The plane-parallel plate 120 is held in the state shown such that its surface normal makes an acute angle with an axis of rotation 15 of the device. The concave part 140 and the convex part 150 the wedge plate 130 are here slightly shifted relative to one another along the mutually facing spherical surfaces.

The holder 160 is with the help of a motor 170 and a wheel driven by the engine 180 in rotation about the axis of rotation 15 added. This also turns the condenser lens 110 , the plane-parallel plate 120 and the wedge plate 130 ,

The lower part 200 the device 10 has a second plane-parallel plate 220 on which in a holder 260 is held. The thickness of the second plane-parallel plate 220 is presently less than the thickness of the plane-parallel plate 120 , The holder 260 is with the help of a motor 270 and a wheel attached to it 280 set in rotation. To replace the second plane-parallel plate 220 can the holder 260 from the device 10 are removed and replaced by another holder, in which a further plane-parallel plate is held with a different thickness.

The light beam 20 , which from a light source, not shown, parallel to the axis of rotation 15 on the device 10 comes to mind, first applies to the condenser lens 110 , It does not change its direction, only its focus. Then he hits the plane-parallel plate 120 where he is offset by a certain amount in parallel. Then he hits the wedge plate 130 through which he then takes a small angle to its original direction of propagation. Then he meets the second plane-parallel plate 220 where he is relocated again in parallel. Then he hits the workpiece 30 ,

The plane-parallel plate 120 is in the holder 160 with the help of a joint 125 attached. This can cause a tilt angle 127 the surface normal of the plane-parallel surfaces relative to the axis of rotation 15 to be changed.

The device 10 also has a device 300 for determining the tilt angle 127 on. The device 300 has a laser 310 on which a measuring light beam 320 emitted. To an impact of the measuring light beam 320 on a side surface 126 the plane-parallel plate 120 to allow the holder has 160 an opening 165 on. The side surface 126 is in the place, which through the opening 165 is exposed, by coating with aluminum highly reflective executed. In addition, the device indicates 300 for determining the tilt angle 127 a detector 330 with a variety of detection elements 335 , which are arranged in a row, as well as a device 340 for calculating the tilt angle.

Furthermore, the device 10 a PID controller 400 , a lead 410 and a sliding contact 420 on, with the PID controller with the device 340 connected to calculate the tilt angle and a control signal via the line 410 and the sliding contact 420 to an actuator 500 can transmit. The actuator 500 is in the holder 160 installed and has a motor 510 , a threaded rod 520 and a driver 530 on, taking the driver 530 with the plane-parallel plate 120 connected is. This allows the tilt angle 127 to be changed.

The measuring light beam 320 is when hitting the side surface 126 reflects and then strikes the detector 330 with the multitude of detection elements 335 , The detection elements 335 each indicate when the measuring light beam 320 on one (or two adjacent) impinges on them. This makes it possible to detect the position of the impact of the reflected measuring light beam.

The detector 330 generates a signal which depends on the position of the impact of the reflected measuring light beam 320 is. The signal is sent to the device 340 to calculate the tilt angle or alternatively directly to the PID controller 400 forwarded. The device 340 calculated for calculating the tilt angle, based on the geometric relationships, that is, in particular the positions of the laser 310 , the side surface 126 and the detector 330 , the current tilt angle 127 ,

The value of the tilt angle 127 is from the institution 340 to the PID controller 400 forwarded. In the PID controller 400 is stored a target value, with which of the device 340 delivered value of the tilt angle 127 is compared. If the two values are identical, nothing further has to be done. However, if the values deviate from each other, the PID controller generates a control signal which compensates for the difference between the two values. With the help of the control signal is a necessary change of the actuator 500 calculated. Accordingly, a signal for changing the actuator 500 generated, which over the line 410 is passed on. The signal is transmitted through the sliding contact 420 in the holder 160 introduced.

By that of the PID controller 400 delivered signal becomes the engine 510 operated such that the tilt angle 127 approaching its target value again. This forms the plane-parallel plate 120 , the device 300 to determine the tilt angle, the PID controller 400 as well as the actuator 500 a closed loop for controlling the tilt angle 120 to a desired setpoint. The set point can also be set by programming the PID controller during operation of the device 10 to be changed.

QUOTES INCLUDE IN THE DESCRIPTION

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

Cited patent literature

• EP 2008/053042 [0003]

Claims (14)

Contraption ( 10 ) for guiding a light beam ( 20 ) with an angle-adjustable optical component which is arranged around a rotation axis ( 15 ) is rotatably driven and is arranged and designed so that a parallel to the axis of rotation incident light beam passes through the angle-adjustable optical component and thereby parallel offset and / or deflected due to refraction, so that the light beam due to the refraction by the angle-adjustable optical component and its Rotation describes a circular path in a plane transverse to the axis of rotation, wherein the angle-adjustable optical component at least one reflection surface ( 126 ) and is held such that a tilt angle ( 127 ) of the angle-adjustable optical component about a tilt axis arranged transversely to the axis of rotation is adjustable, characterized by a device ( 300 ) for determining the tilt angle ( 127 ), with a light source ( 310 ), which is arranged adjacent to the angle-adjustable optical component and, when in operation, a measuring light beam ( 320 ) in the direction of the angle-adjustable optical component such that the measuring light beam ( 320 ) at least during a part of a complete revolution of the optical element from the reflection surface ( 126 ) of the angle-adjustable optical component is reflected, and a detector ( 330 ), which is arranged such that the reflected measuring light beam ( 320 ) hits him. Device according to claim 1, having a plane-parallel plate ( 120 ), which has two plane-parallel surfaces, wherein the angle-adjustable optical component, the plane-parallel plate ( 120 ) and wherein the tilt angle ( 127 ) an angle of a surface normal of the plane-parallel surfaces relative to the axis of rotation ( 15 ). Device according to one of the preceding claims, comprising a wedge plate ( 130 ), wherein the wedge plate comprises at least a first and a second optical element ( 140 . 150 ) and has two planar surfaces as end faces, wherein the optical elements of the wedge plate - facing each other, have complementary spherical surfaces, of which the one spherical surface is a concave surface of the first optical element ( 140 ) and the other spherical surface forms a convex surface of the second optical element (FIG. 150 ) and the concave surface and the convex surface have the same radius of curvature, and - are to be displaced relative to each other along the mutually facing spherical surfaces, that the planar surfaces facing away from the respective spherical surface of a respective optical element surfaces either plane-parallel or in one Wedge angle to each other, wherein the angle-adjustable optical component is the first or the second optical element and wherein the tilt angle ( 127 ) an angle of a surface normal of the end face of the first and second optical element relative to the axis of rotation ( 15 ). Apparatus according to claim 3, wherein the first and second optical elements are angularly adjustable optical components and at least two measuring light beams and detectors are provided. Device according to claims 2 and 3 or 4, wherein the wedge plate ( 130 ) in the propagation direction of the light beam ( 20 ) after the plane-parallel plate ( 120 ) is arranged. Device according to one of the preceding claims, wherein the detector ( 330 ) is designed such that it detects the position of the impact of the reflected measuring light beam ( 320 ) can detect. Apparatus according to claim 6, wherein the detector ( 330 ) several detection elements arranged in a row ( 335 ) having. Device according to one of claims 6 or 7, further comprising a device ( 340 ) for calculating the tilt angle as a function of the position of the impact of the reflected measuring light beam (US Pat. 320 ) having. Device according to one of the preceding claims, wherein the reflection surface ( 126 ) of the adjustable optical component is a side surface of the optical component which is arranged such that the measuring light beam strikes the side surface at least temporarily during operation of the device and is reflected from the side surface in dependence on the tilt angle. Device according to one of the preceding claims, wherein the reflection surface ( 126 ) of the adjustable optical component is coated at least partially reflecting. Device according to one of the preceding claims, which further comprises an actuator ( 500 ), which the tilt angle ( 127 ), as well as a controller ( 400 ), which is designed, the actuator ( 500 ) such that the reflected measuring light beam ( 320 ) in a desired position on the detector ( 330 ). Apparatus according to claim 11, wherein the controller ( 400 ) is a P-controller, a PI controller, a PID controller or a PD controller. Device according to one of the preceding claims, which further comprises a focusing optics ( 110 ), which in the propagation direction of the light beam ( 20 ) is arranged in front of the adjustable optical component. Device according to one of the preceding claims, which further comprises a second plane-parallel ( 220 ) Plate, which in the propagation direction of the light beam ( 20 ) is arranged after the adjustable optical component.

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