DE102015005779A1 - Method for calibrating an apparatus for inspecting an optical device and method for inspecting an optical device - Google Patents

Abstract

The invention relates to a method for calibrating a device (100) for examining an optical device (270), the method having the following features: - holding (670) imaging optics (210) in a beam path of an electromagnetic radiation (106) a wave property of the electromagnetic radiation (106) is represented by a plane wave; and moving (674) a deflector (104) to deflect the electromagnetic radiation (106) between an inactive position and an active position, wherein the deflector (104) is disposed in the inactive position out of the beam path and in the active position in the beam path is arranged in front of the imaging optics (201) in order to set an angle of incidence (212) of the electromagnetic radiation (106) on the imaging optics (201).

Description

State of the art

The present invention relates to an apparatus and method for calibrating a device for inspecting an optical device, such as an objective.

The optical device to be examined, for example a lens, can in turn be used in conjunction with a wavefront sensor to measure further optical devices.

The optical device to be examined, for example a lens, and the wavefront sensor usually form a unit whose summary optical properties must be known before the actual use as a measuring system.

The DE 197 22 342 A1 describes an absolute test of spherical surfaces and objectives with partially coherent laser radiation using a wavefront sensor.

Disclosure of the invention

Against this background, the present invention provides an improved method of inspecting an optical device. Advantageous embodiments emerge from the respective subclaims and the following description. The method for examining an optical device is preceded by a method for calibrating a device for examining an optical device.

A method for calibrating an apparatus for examining an optical device therefore initially has the following features:
Holding an imaging optics in a beam path of an electromagnetic radiation, wherein a wave property of the electromagnetic radiation is represented by a plane wave; and moving a deflector for deflecting the electromagnetic radiation between an inactive position and an active position, wherein the deflector is disposed in the inactive position out of the beam path and in the active position in the beam path in front of the imaging optics, at an angle of incidence of the electromagnetic radiation to adjust the imaging optics.

The device may, for example, be a wavefront inspection device, a wavefront inspection device or a part of such a device. The device can be used to measure an optical device subsequently, ie after the step of calibrating. A property of the optical device to be investigated may be, for example, a surface condition, material properties or the wavefront aberrations of the optical device. By an optical device, for example, a lens can be understood. In general, an optical device can be understood as meaning an optical device, an optical component is an optical component or, for example, a surface. By electromagnetic radiation, for example, a light beam in a visible or invisible to the human eye spectrum can be understood. A plane wave may be understood to mean a real plane wave, such as may be generated using a pinhole and a collimator tuned thereto. A plane wave can be characterized by wavefronts that are extended perpendicular to the propagation direction of the electromagnetic radiation. A wavefront can be understood to mean an area of the same phase angle. A beam path may be understood as a geometric course of the electromagnetic radiation, for example from a source of the electromagnetic radiation to the optical device and through the optical device. The holding device may be a mechanical element to which the imaging optics can be permanently or removably attached. The deflector may be an optical element. The deflecting device may be configured to change a direction of propagation of the electromagnetic radiation by the effect of the refraction, when the deflecting device is located in the beam path of the electromagnetic radiation. The deflection device can be designed to emit electromagnetic radiation incident at an angle of incidence into the deflection device in a deflection angle characteristic of the deflection device, the deflection angle for the electromagnetic radiation. In this case, the deflection device can be designed to emit incident electromagnetic radiation at the angle of incidence exclusively in the characteristic angle of reflection. Thus, an azimuthal directional component of a direction of the emitted electromagnetic radiation may be dependent on an angular position of the deflection device. In the inactive position, the deflector may be located at a location external to the beam path of the electromagnetic radiation passing through the optical device. Thus, a trajectory of the electromagnetic radiation between a source of electromagnetic radiation and the imaging optics is not affected by the deflector when the deflector is in the inactive position. In the active position, the deflector is in relation to a propagation direction of the electromagnetic radiation in the Beam path arranged in front of the imaging optics. The deflecting device influences the course of the electromagnetic radiation between a source of the electromagnetic radiation and the imaging optics by the deflecting device. Thus, the beam path of the electromagnetic radiation from different gradients, depending on whether the deflector is in the inactive position or the active position. Due to the deflecting effect of the deflection device, an angle of incidence of the electromagnetic radiation on the imaging optics changes, depending on whether the deflection device is in the inactive position or the active position. Thus, the optical device can be measured by moving the deflector between the inactive position and the active position at two different angles of incidence of the electromagnetic radiation. When changing between active and inactive position usually occur positioning errors of the deflector. The proposed deflection device makes it possible to set the desired deflection angle despite these errors.

The approach described can be used, for example, in connection with the calibration of wavefront inspection stations for measuring optical devices in the form of field angle objectives. As a field of application, for example, all Wellenflächenprüfstände for lens testing come into consideration.

Wave surface test stands are calibrated before use. This usually requires a known wavefront adapted to the later test. The approach described is suitable for generating such calibration wavefronts for different but exactly known field angles. This makes it possible to measure the optical device, for example an objective to be measured, just below these field angles.

Advantageously, using the described approach, it is possible to dispense with the use of a calibration objective which has the same imaging properties as the optical device, for example a test object to be measured later. In order to achieve a good calibration of the device, for example as part of a test stand, it is therefore not necessary to provide an optical device used for calibration, for example a calibration lens, approximately perfectly and error-free, as is also difficult to achieve in practice. With the proposed deflection device, it is possible to produce an approximately perfect and error-free wavefront. This property is favored by the simplicity of the design of the deflector.

Also, using the approach described for overcoming a so-called "off-axis" calibration problem, it is no longer necessary to pivot the entire device, for example in the form of a measuring device, in order to always be able to measure centered along the optical axis Calibration at field angles is omitted. Advantageously, thus eliminating the need for additional movements of the device. As a result, the technical complexity can be reduced and additional operating times can be omitted.

Thus, the described approach has the advantages that it can be dispensed with perfect, difficult to implement calibration lenses and complex movements.

According to one embodiment, the device for examining an optical device comprises a radiation device for emitting the electromagnetic radiation. The radiation device can represent or comprise a radiation source, for example a light source, a laser or a light-emitting diode. Such a radiation source can already be designed to provide the electromagnetic radiation with a characteristic corresponding to the plane wave. Alternatively, the characteristic of a plane wave may be achieved by at least one optical element configured to influence the electromagnetic radiation radiated from a radiation source so as to obtain the characteristic of the plane wave. Thus, in addition to or as an alternative to a radiation source, the radiation device can have an optical element which is suitable for emitting a received electromagnetic radiation as a plane wave. By using a passive or active radiation device according to the embodiment, electromagnetic radiation having a property suitable for examining the optical device can be provided.

For example, the radiation device may have a collimator. Using a collimator, which can be used for example in combination with a pinhole, a parallel beam path of an electromagnetic radiation generated by a light source can be generated. Such a parallel beam path can have the characteristic of a plane wave.

The radiation device can be designed to emit the electromagnetic radiation with a propagation direction oriented parallel to an optical axis of the optical imaging optics. This can be achieved that the electromagnetic radiation in parallel to the optical axis impinges on the imaging optics.

According to one embodiment, in the active position between a first angular position and at least one second angular position, the deflection device can be arranged to be rotatable about an axis of rotation in order to set an azimuth angle of the electromagnetic radiation. The axis of rotation may be parallel to an incident on the surface of the deflector portion of the beam path of the electromagnetic radiation. According to one embodiment, the axis of rotation of the optical axis may correspond to the optical imaging optics. Due to the different angular positions of the deflecting device, the beam path of the electromagnetic radiation can be deflected in different directions before impinging on the imaging optics. As a result, different azimuth angles can be set in which the electromagnetic radiation strikes the imaging optics. Advantageously, the deflection device can be designed such that only the azimuth angle, but not the angle of incidence of the electromagnetic radiation on the optical device, changes as a result of the rotation of the deflection device. This feature is an outstanding feature of the proposed device.

The method of calibrating an optical device inspection apparatus may include a step of rotating the deflector about an axis of rotation of the deflector. The axis of rotation may, for example, be aligned parallel to the optical axis of the imaging optics or correspond to the optical axis. The step of rotating may be performed when the deflector is located in the active position. Alternatively, the step of turning may also be performed when the deflector is in the inactive position. By rotating the deflection device, as already stated, different azimuth angles of the electromagnetic radiation can be set.

The method of calibrating an optical device inspection apparatus may include a step of detecting a characteristic of a wavefront of the electromagnetic radiation after passing through the imaging optics. The step of detecting may be repeatedly performed several times. For example, the step of detecting may be performed while the deflector is in the inactive position to detect a calibration characteristic associated with the inactive position. Further, the step of sensing may be performed while the deflector is in the active position to detect a calibration characteristic associated with the active position. In this way, characteristics of electromagnetic radiation incident on the imaging optics from different directions can be detected.

Advantageously, the step of detecting can be carried out while the deflecting device is in the active position in a first angular position in order to detect a calibration characteristic assigned to the first angular position. Further, the step of sensing may be performed while the deflector is in a second angular position in the active position to detect a calibration characteristic associated with the second angular position. In further steps of the detection, further calibration characteristics associated with further angular positions of the deflection device can be detected. As already stated, a calibration characteristic can relate to the wavefront of the electromagnetic radiation.

In order to move the deflection device, the device may have a movement device. The moving means may be configured to move the deflector between the active position and the inactive position in response to a control signal. Furthermore, the movement device can be designed to rotate the deflection device in the active position between the first azimuthal angular position and the at least one second azimuthal angular position in response to a further control signal. The movement device can be, for example, an electromechanical device by means of which the deflection device can be automatically moved to a desired position. Alternatively, a purely mechanical movement device can be used which, for example, allows an operator of the device to move the deflection device into a desired position.

The deflection device may have an entrance surface for the electromagnetic radiation and an exit surface for the electromagnetic radiation. The entrance surface and the exit surface can be designed as flat surfaces. The entrance surface and the exit surface may be aligned opposite each other and inclined to each other. By a suitable choice of a material of the deflection device and a suitable choice of a tilt angle between the entry surface and the exit surface, a desired deflection angle for the incident on the deflection electromagnetic radiation can be specified.

For example, the deflection can be designed as a wedge plate. Such a deflector can be manufactured inexpensively with a high quality and is easy to handle. Alternatively, the deflection device can also be designed as a so-called DOE (Diffractive Optical Element) or as a liquid crystal.

• – Kalibrieren einer Vorrichtung gemäß einem der Ansprüche 1 bis 6;
• – Bereitstellen der zu untersuchenden optischen Einrichtung in einem Strahlengang einer elektromagnetischen Strahlung, wobei eine Welleneigenschaft der elektromagnetischen Strahlung durch eine ebene Welle repräsentiert wird;
• – Bereitstellen der Abbildungsoptik im Strahlengang nach der zu untersuchenden optischen Einrichtung;
• – Erfassen einer Charakteristik einer Wellenfront der elektromagnetischen Strahlung nach Passieren der Abbildungsoptik;
• – Berücksichtigen einer Kalibriercharakteristik gemäß einem der Ansprüche 1 bis 6.

The invention also provides a method for examining an optical device, the method having the following features:

• - Calibrating a device according to one of claims 1 to 6;
• - Providing the optical device to be examined in a beam path of an electromagnetic radiation, wherein a wave property of the electromagnetic radiation is represented by a plane wave;
• - Providing the imaging optics in the beam path after the optical device to be examined;
• Detecting a characteristic of a wavefront of the electromagnetic radiation after passing through the imaging optics;
• - Considering a calibration characteristic according to one of claims 1 to 6.

Advantageously, the step of detecting a characteristic of a wavefront of the electromagnetic radiation comprises a first detection, wherein in this step the electromagnetic radiation does not include an angle of incidence with the imaging optic and a second detection, wherein the electromagnetic radiation in this step includes an angle of incidence with the imaging optic. According to the invention, the technical feature "no angle of incidence" is understood to mean an angle of approximately 0 °, preferably exactly 0 °.

In a further advantageous embodiment, the step of the second detection is realized by a movement of the source of the electromagnetic radiation. In a further advantageous embodiment, the step of second detection is achieved not by a movement of the source of the electromagnetic radiation, but by a plurality of radiation sources. For example, this plurality of radiation sources may be embodied as a board with a plurality of LEDs.

1 a schematic representation of an apparatus for examining an optical device according to an embodiment of the present invention in the state of calibration;

2 a schematic representation of an apparatus for examining an optical device according to an embodiment of the present invention in the state of calibration;

3a a schematic representation of an apparatus for examining an optical device according to an embodiment of the present invention in the state of calibration;

3b a further schematic representation of an apparatus for examining an optical device according to an embodiment of the present invention in the state of calibration;

4 a plan view of a deflector according to an embodiment of the present invention;

5 a flowchart of a method for calibrating an apparatus for examining an optical device according to an embodiment of the present invention;

6 a schematic representation of an apparatus for inspecting an optical device according to an embodiment of the present invention; and

7 a further schematic representation of an apparatus for examining an optical device according to an embodiment of the present invention.

In the following description of favorable embodiments of the present invention, the same or similar reference numerals are used for the elements shown in the various figures and similar acting, with a repeated description of these elements is omitted.

1 shows a schematic representation of a device 100 for investigating an optical device according to an exemplary embodiment of the present invention, wherein first of all the calibration of the device should be discussed. The device 100 has a holding device 102 and a deflector 104 on.

The holding device 102 is designed to be an imaging optic 210 to keep. The imaging optics 210 is in 2 shown. For this purpose, the holding device 102 For example, detachable fastening devices for attaching the imaging optics 210 on the holding device 102 exhibit. The holding device 102 is designed to hold the imaging optics so that the imaging optics in a beam path of electromagnetic radiation 106 is held. If the imaging optics of the holding device 104 is held, the electromagnetic radiation hits 106 during operation of the device 100 in a reference angle to the imaging optics. For example, the holding device 104 be formed to hold the imaging optics so that the electromagnetic radiation 106 impinges on the imaging optics parallel to the optical axis of the imaging optics.

The deflection device 104 is arranged movable. In 1 is the deflection device 104 shown in an inactive position in which the deflector 104 outside the beam path of the electromagnetic radiation 104 is arranged. Thus, the electromagnetic radiation 106 before hitting one in the holding device 102 Anordenbare imaging optics not by the deflection 104 affected. As if by an arrow 108 indicated, the deflection can 106 moving from the inactive position to an active position. In the active position is the deflector 104 as it is in the 2 and 3 is shown in the beam path of the electromagnetic radiation 106 arranged.

2 shows a schematic representation of a device 100 for examining an optical device according to an embodiment of the present invention in the state of calibration, wherein the optical device is not shown in this illustration. In the device 100 it can be an embodiment of the basis of 1 act described device. Unlike the in 1 The device described is the deflection device 104 the in 2 shown device 100 shown in the active position in which the deflector 104 in the beam path of the electromagnetic radiation 106 is arranged. Furthermore, the imaging optics 210 shown by the holding device 102 in the beam path of the electromagnetic radiation 106 is held. The deflection device 104 is designed to absorb the electromagnetic radiation 106 around a deflection angle 212 , also called field angle, distract. In this way, the electromagnetic radiation hits 106 in one of that, based on 1 said reference angle deviating angle of incidence on the optical device 210 on. A size of the angle of incidence corresponds to a size of the deflection angle according to this embodiment 212 ,

According to one embodiment, the deflection device 104 rotatably disposed about an axis of rotation, which is subsequently the optical axis 214 may correspond to the optical device. According to this embodiment, the optical axis corresponds 214 a direction of electromagnetic radiation 106 before hitting the deflector 104 , By turning the deflector 104 can the deflector 104 perform a rotary motion as indicated by another arrow 216 is indicated. By a rotation of the deflector 104 from a first angular position to a second angular position, a direction changes in which the electromagnetic radiation 106 on the imaging optics 210 meets. In this case, a horizontal angle, also called azimuth, azimuth angle or azimuthal angle, changes the beam path of the electromagnetic radiation 106 between the deflector 104 and the holding device 102 or the imaging optics 210 , The horizontal angle according to this embodiment is an angle which is measured in a plane to which the optical axis 214 is perpendicular. The corresponding deflection angle 212 changes during the rotary motion of the deflector 104 Not.

In 2 are also a plurality of optional devices 220 . 222 . 226 . 230 . 234 the device 100 shown, which are described below. The device 100 can according to different embodiments, one, several or all of these optional devices 220 . 222 . 226 . 230 . 234 exhibit.

So is in 2 a radiation device 220 for emitting the electromagnetic radiation 106 shown. According to one embodiment, the radiation device 220 trained to the electromagnetic radiation 106 as a plane wave or, in the realm of the technically feasible, as an approximate plane wave, a so-called real plane wave. The deflection device 104 is formed to the input side in the deflection 104 incoming plane wave output on the output side as a deflected plane wave. Thus, the electromagnetic radiation hits 106 as a plane wave on the imaging optics 210 on. The radiation device 220 and the holding device 102 can be aligned with each other, that of the radiation device 220 emitted electromagnetic radiation 106 parallel to the optical axis 214 the imaging optics 210 is emitted when the imaging optics 210 from the holding device 102 is held.

The holding device 102 can be shaped so that an imaging optics 210 in the holding device 102 used and after calibration using electromagnetic radiation 106 again from the holding device 102 can be removed.

According to one embodiment, the device 100 a movement device 222 on. The movement device 222 is with the deflector 104 coupled and configured to the deflector 104 move from the active position to the inactive position. According to one embodiment, the movement device 222 further formed to the deflecting device 104 about an axis of rotation of the deflector 104 to turn, for example, as indicated by the arrow 216 is indicated. The movement device 222 can a for moving the deflector 104 have appropriate mechanics. According to one embodiment, the movement device 222 a drive, such as a servomotor for moving the deflector 104 on. In this case, the movement device 222 or the device 100 an interface for receiving a control signal 224 and be adapted to a movement of the deflector 104 in response to receipt of the control signal 224 perform. Accordingly, the device 100 a control device 226 for providing the control signal 224 exhibit. The control device 226 may be configured to a plurality of control signals 224 to the movement device 222 provide to the deflector 104 for example, moving from the inactive position to the active position, and rotating one or more times in the active position, to the deflector 104 one after the other in a plurality of angular positions. Subsequently, the deflection can 104 as if by an arrow 228 indicated to be moved back to the inactive position. The movement device 222 can the in 4 correspond to rotating means or include such a rotating device.

According to one embodiment, the device 100 a sensor device 230 on, after the imaging optics 210 in the beam path of the electromagnetic radiation 106 is arranged. The electromagnetic radiation 106 becomes after passing the imaging optics 210 from the sensor device 230 detected. The sensor device 230 is adapted to a characteristic of a sensor surface of the sensor device 230 incident electromagnetic radiation 106 and to detect a sensor signal representing the detected characteristic 232 provide. According to one embodiment, the sensor device 230 is implemented as a wavefront sensor configured to detect a characteristic of a wavefront of the electromagnetic radiation perceived as a wave 106 after exiting the imaging optics 210 capture. Thus, that of the sensor device 230 provided sensor signal 232 used to generate a wavefront error of the imaging optics 210 to recognize.

The device 100 according to one embodiment, a determination device 234 on or is via an interface with the determining device 234 coupled. The determining device 234 is designed to receive the sensor signal 232 from the sensor device 230 to receive and evaluate. According to one embodiment, the determining device 234 configured to a plurality of sensor signals 232 to recieve. The sensor signals 232 differ in that they have electromagnetic radiation 106 are assigned in different directions to the imaging optics 210 have fallen. For example, a first sensor signal 232 be associated with a first time to which the deflection 104 is in the inactive position. A second sensor signal 232 may be associated with a second time at which the deflector 104 is in the active position in a first angular position. A third sensor signal may be associated with a third time to which the deflection device 104 is in the active position in a deviating from the first angular position second angular position. Accordingly, further sensor signals 232 be assigned to other times, the other positions of the deflection 104 and thus further directions of incidence of the electromagnetic radiation 106 on the imaging optics 210 assigned. The determining device 234 may be configured to be based on one or more sensor signals 232 based examination signal 236 provide.

The examination result signal 236 For example, information about one or more wavefront errors of the imaging optics 210 include. The examination result signal 236 can be advantageously used to calibrate the device and use it as a reference for subsequent measurements. In these measurements, usually the deflection device 104 through the optical device to be measured 270 replaced. The optical device may be, for example, a lens. By subtracting the previously recorded examination result signal from the measurement of the wavefront error of the objective to be measured, one obtains the actual error of the objective without the influence of the other components of the device, ie the imaging optics 210 , the holding device 102 and the sensor device 230 ,

According to one embodiment, the control device 226 designed to be a trigger signal 238 to the determination device 234 or the sensor device 230 provide. The trigger signal 238 can indicate that the deflector 104 has taken a position in which a property of the imaging optics 210 passed electromagnetic radiation 106 is to capture. For example, the determination device 234 be configured to be responsive to receipt of the trigger signal 238 the sensor signal 232 from the sensor device 230 read out or the sensor device 230 may be configured to be responsive to receipt of the trigger signal 238 a wavefront characteristic of the sensor device 230 incident electromagnetic radiation 106 and via the sensor signal 232 provide.

According to one embodiment, the device 100 a carrier structure 240 by which, for example, the radiation device 220 , the movement device 222 , the holding device 102 and the sensor device 230 being held. For example, the facilities may 220 . 222 . 102 . 230 using the support structure 240 be aligned with each other, so that the beam path of the electromagnetic radiation 106 from the radiation device 220 through the deflector 104 and the imaging optics 210 to the sensor device 230 runs. The support structure 240 can as a housing or part of a housing of the device 100 be executed.

According to one embodiment, at least one further deflection device 104 provided, or it may be the deflection shown 104 be replaced by at least one other deflector. In this way, the electromagnetic radiation 106 under at least one further angle of incidence, passing through one through the further deflector 104 defined further deflection angle is defined on the imaging optics 210 be steered.

Furthermore, it is possible in a further embodiment, the device without the imaging optics 210 to calibrate. In this embodiment, therefore, only the sensor device would 230 calibrated and used as a reference for subsequent measurements.

3a shows a schematic representation of a device 100 for examining an optical device in the state of calibrating the device according to an embodiment of the present invention. In the device 100 it may be an embodiment of the device described with reference to the preceding figures.

According to the in 3a embodiment shown includes the radiation device 220 a point light source 350 for providing the electromagnetic radiation 106 and a collimator 352 for generating a parallel beam path of the electromagnetic radiation 106 ,

The device 100 has a radiation device 220 for emitting electromagnetic radiation 106 , which according to this embodiment is a plane wave along an optical axis. The electromagnetic radiation 106 radiates the imaging optics 210 which is implemented as a wavefront sensor imaging optical system according to this embodiment, along the optical axis. After the radiation of the imaging optics 210 meets the electromagnetic radiation 106 to a wavefront sensor image plane in which according to this embodiment, a sensor device 230 is arranged in the form of a wavefront sensor. According to this embodiment, the electromagnetic radiation 106 through the imaging optics 210 brought to the wavefront sensor image plane, in particular focused.

3b shows a further schematic representation of in 3a shown device 100 for investigating an optical device 210 according to an embodiment of the present invention in the state of calibrating the device. In the in 3b The representation shown is the deflection device 104 in the beam path of the electromagnetic radiation 106 between the collimator 352 and the imaging optics 210 arranged. The on the deflector 104 impinging plane wave is caused by the deflector 104 deflected and runs as a plane wave along a field angle, in 2 Also referred to as deflection angle, on the imaging optics 210 to. Due to the deflection by the deflector 104 becomes the imaging optics 210 , here the wavefront sensor imaging optics, irradiates along the field angle. After irradiation of the imaging optics 210 meets the electromagnetic radiation 106 again to the sensor device 230 ,

The deflection device 104 is designed according to this embodiment as a wedge plate. The deflection device 104 thus has an entrance surface and an exit surface inclined to the entry surface. According to this embodiment, the optical axis, here the propagation direction of the electromagnetic radiation 106 after the collimator 352 corresponds approximately perpendicular to the entrance surface of the deflector 104 , Based on 3a and 3b the approach described will be described below with reference to specific embodiments. The described approach offers the possibility of independent of perfect calibration lenses and without rotation of the sensor unit 230 an optical device 270 , For example, a lens, along the optical axis and at exactly defined angles inclined to the optical axis with respect to wavefront error to measure. A calibration method based thereon is particularly applicable if at least one side of the optical device to be measured 270 requires a plane wave as input shaft. This is the case with so-called collimators or afocal telescopes. Microscope lenses also fall into this category.

To generate the plane wave along the optical axis of the optical device to be measured and to generate the plane wave along the oblique field directions, the deflecting device 104 , here an optical wedge plate 104 , on used a rotating device. The wedge plate 104 has the property that the deflection angle of the passing beam 106 almost independent of the angle of incidence of the beam 106 on the first surface of the wedge plate 104 is. With this property, even with relatively relaxed mechanical fault tolerances a very defined and stable beam deflection by the wedge plate 104 be generated. In particular, to the movement mechanics 222 no great accuracy requirements are made regarding angle of incidence on the wedge plate 104 ,

According to one embodiment, the approach described is used to calibrate a wave surface test rig. The plane wave for calibrating the Wellenflächenprüfstandes is in the usual way by a pinhole, a so-called small "pin-hole", the point light source 350 serves, and a matched collimator 352 generated. This plane wave will be without the wedge plate first 104 and the optical device to be measured 270 passed through the device. By doing a measurement using the sensor device 230 is the optical axis of the device 100 determined in the form of a test bench and the optical device to be measured. Then the wedge plate 104 on the input side in the beam path of the radiation 106 introduced to the plane calibration wave of the radiation 106 fall under the desired field angle in the imaging optics. By turning the wedge plate 104 Any azimuth angle can be around the optical axis 216 for calibration.

4 shows a plan view of a deflector 104 as already described with reference to the preceding figures, according to an embodiment of the present invention.

When the deflector 104 in the active position, the electromagnetic radiation hits 106 according to this embodiment, perpendicular to an entrance surface of the deflector 104 , When the deflector 104 In the inactive position, the electromagnetic radiation hits 106 according to this embodiment thus also perpendicular, ie with a field angle of 0 °, to the optical device to be examined.

When the deflector 104 located in the active position, rejects the electromagnetic radiation 106 after passing the deflector 104 on the one hand a field angle, as it is based on 2 is described. The field angle is at every azimuthal angular position 561 . 562 . 563 . 564 the deflection device 104 the same. Exemplary are in 4 four azimuthal angular positions 561 . 562 . 563 . 564 the deflection device 104 shown, wherein a first angular position 561 a rotation angle of 0 °, a second angular position 562 a rotation angle of 90 °, a third angular position 563 a rotation angle of 180 ° and a fourth angular position 564 represents a rotation angle of 270 °. As indicated by the arrows in 4 is marked each angular position 561 . 562 . 563 . 564 associated with a horizontal direction in which the electromagnetic radiation 106 after passing the deflection device 104 is aligned. In terms of the first angular position 561 has a directional vector of the electromagnetic radiation 106 after passing the deflection device 104 for example, an azimuth angle of 0 °. After turning the deflector 104 in the second angular position 562 as indicated by the arrow 216 is indicated, has a direction vector of the electromagnetic radiation 106 after passing the deflection device 104 here an azimuth angle 565 from 90 ° up.

According to one embodiment, the optical device 270 be measured in the form of a lens at five field points. On the optical axis (0 ° field angle) and under four field angles (5 ° field angle and 0 ° azimuth angle, 5 ° field angle and 90 ° azimuth angle, 5 ° field angle and 180 ° azimuth angle, 5 ° field angle and 270 ° azimuth angle) ,

For this purpose, the wedge plate is in the state of calibration 104 rotated azimuthally by the same azimuth angle, ie in the angular positions 561 . 562 . 563 . 564 turned. The field angle, the deflection angle of the wedge plate 104 corresponds, remains unchanged, even if during the rotation of the wedge plate 104 small mechanical angle errors occur.

This ensures an independent and stable calibration procedure, independent of a calibration lens and stable due to the wedge plate 104 is. As a result, simpler test stands can be realized, due to the fact that in addition to the movement of the wedge plate 104 no movements in the measurement are required. Due to the lack of such further movements, a high measuring speed can be achieved at the test stand.

5 shows a flowchart of a method for calibrating an apparatus for inspecting an optical device according to an embodiment of the present invention. The method can be carried out, for example, in connection with a device described above.

In one step 670 An imaging optics is held in a beam path of electromagnetic radiation. In one step 672 a deflector is moved. The deflection device serves to deflect the electromagnetic radiation before the electromagnetic radiation hits the imaging optics. Depending on the starting position of the deflection, the deflection in the step 672 from an inactive position to an active position, from the active position to the inactive position, or to a changed angular position. The step 672 can thus a plurality of sub-steps 674 . 676 comprising a step 674 can be performed to move the deflector between the inactive and the active position and a step 676 can be performed to rotate the deflector for setting different angular positions. The substeps 674 . 676 can be repeated and executed in any suitable order.

In one embodiment, the method further comprises an optional step 678 detecting a characteristic of a wavefront of the electromagnetic radiation after passing through the imaging optics. The step of grasping 678 can be performed, for example, using a sensor device described with reference to the preceding figures. The step of grasping 678 can be carried out repeatedly, for example, respectively, when the deflector has been moved to a new position. Each detected characteristic can be assigned to a direction of incidence of the electromagnetic radiation on the imaging optics.

The 6 . 7a and 7b show various embodiments for examining or characterizing an optical device after the calibration procedure is completed. First, it should be on the 6 and 7a be discussed in more detail. Again 6 can be seen, in a method for examining the optical device, the deflection 104 through the optical device to be examined 270 replaced. For example, the optical device to be examined may be an objective 270 act. This lens will now be measured at five field points. On the optical axis (0 ° field angle) and under four field angles (5 ° field angle and 0 ° azimuth angle, 5 ° field angle and 90 ° azimuth angle, 5 ° field angle and 180 ° azimuth angle, 5 ° field angle and 270 ° azimuth angle) , By this is meant that the electromagnetic radiation after passing through the lens does not include an angle with the imaging optics (0 ° field angle) or an angle with the imaging optics includes (5 ° field angle). Thus, the lens becomes 270 so measured exactly in the states that were previously calibrated without the lens by means of the deflector.

The 6 and the 7a show the method for examining an optical device, the light from a point light source 350 in one after the optical device 270 level wave 106 transformed, a so-called collimator. The collimator is tested, in the aforementioned two states, namely in a first state, in which the electromagnetic radiation after passing through the optical device has no angle of incidence with the imaging optics 210 includes ( 6 ) and in a second state in which the electromagnetic radiation after passing through the optical device has an angle of incidence with the imaging optics 210 includes. Thus, the first state of the method according to 6 the condition in the calibration phase according to 3a and the second state of the method according to 7a the condition in the calibration phase according to 3b , The different azimuth angles are now achieved by the point light source 350 is moved in different directions according to the arrows in such a way that the four directions of movement are perpendicular to the optical axis.

Another possibility is that the point light source 350 not perpendicular to the optical axis according to 7a is moved, but together with the illumination collimator 352 at an angle 351 , which corresponds to the field angle, is rotated. This arrangement is suitable optical devices 270 to check which plane waves at the entrance in also plane waves at the output transferred, so-called afocal arrangements.

The embodiments described and shown in the figures are chosen only by way of example. Different embodiments may be combined together or in relation to individual features. Also, an embodiment can be supplemented by features of another embodiment.

Furthermore, method steps according to the invention can be repeated as well as carried out in a sequence other than that described. If an exemplary embodiment comprises a "and / or" link between a first feature and a second feature, then this is to be read so that the embodiment according to one embodiment, both the first feature and the second feature and according to another embodiment either only first feature or only the second feature.

LIST OF REFERENCE NUMBERS

100

contraption

102

holder

104

Deflector

106

electromagnetic radiation

210

Optical imaging device

212

deflection

214

optical axis

216

rotary motion

220

radiation device

222

mover

224

control signal

226

control device

228

movement direction

230

sensor device

232

sensor signal

234

determiner

236

Investigation result signal

238

trigger signal

240

support structure

270

optical device

350

Point light source

351

deflection

352

collimator

561

first angular position

562

second angular position

563

third angular position

564

fourth angular position

565

azimuth angle

670

Step of holding

672

Step of moving

674

Step of moving

676

Step of turning

678

Step of grasping

QUOTES INCLUDE IN THE DESCRIPTION

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

Cited patent literature

• DE 19722342 A1 [0004]

Claims (9)

Method for calibrating a device ( 100 ) for examining an optical device ( 270 ), the method comprising the following features: - holding ( 670 ) an imaging optics ( 210 ) in a beam path of an electromagnetic radiation ( 106 ), wherein a wave property of the electromagnetic radiation ( 106 ) is represented by a plane wave; and moving ( 674 ) a deflection device ( 104 ) for deflecting the electromagnetic radiation ( 106 ) between an inactive position and an active position, the deflection device ( 104 ) is arranged in the inactive position outside the beam path and in the active position in the beam path in front of the imaging optics ( 201 ) is arranged to provide an angle of incidence ( 212 ) of electromagnetic radiation ( 106 ) on the imaging optics ( 201 ). Method according to claim 1, with a step ( 676 ) of turning the deflector ( 104 ) about an axis of rotation of the deflection device ( 104 ). Method according to claim 1 or 2, comprising a step ( 678 ) of detecting a characteristic of a wavefront of the electromagnetic radiation ( 106 ) after passing through the imaging optics ( 210 ), wherein the step ( 678 ) of detecting while the deflection device ( 104 ) is in the inactive position to detect a calibration characteristic associated with the inactive position, and the step of 678 ) of detecting while the deflection device ( 104 ) is in the active position to detect a calibration characteristic associated with the active position. Method according to claim 3, wherein the step ( 678 ) of detecting while the deflection device ( 104 ) in the active position in a first angular position ( 561 ) to one of the first angular position ( 561 ) and to detect the calibration characteristic associated with 678 ) of detecting while the deflection device ( 104 ) in the active position in a second angular position ( 562 ) to one of the second angular position ( 562 ) to be assigned associated calibration characteristic. Method according to one of the preceding claims, in which the deflection device ( 104 ) an entrance surface for the electromagnetic radiation ( 106 ) and an exit surface for the electromagnetic radiation ( 106 ), wherein the entrance surface and the exit surface are aligned opposite each other and obliquely to each other. Method according to one of the preceding claims, in which the deflection device ( 104 ) is designed as a wedge plate. Method for examining an optical device ( 270 ), the method comprising the following features: - calibrating a device according to one of claims 1 to 6; Providing the optical device to be examined ( 270 ) in a beam path of an electromagnetic radiation ( 106 ), wherein a wave property of the electromagnetic radiation ( 106 ) is represented by a plane wave; - Providing the imaging optics ( 210 ) in the beam path after the optical device to be examined ( 270 ); Detecting a characteristic of a wavefront of the electromagnetic radiation ( 106 ) after passing through the imaging optics ( 210 ); - Considering a calibration characteristic according to one of claims 1 to 6. The method of claim 7, wherein the step of detecting a characteristic of a wavefront of the electromagnetic radiation comprises a first detection, wherein in this step the electromagnetic radiation includes no angle of incidence with the imaging optic and comprises a second detection, wherein the electromagnetic radiation comprises in this step Incident angle with the imaging optics includes. A method according to claim 8, wherein the step of second detecting is realized by movement of the source of electromagnetic radiation.

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