DEVICE FOR SWIVELING A MIRROR ELEMENT WITH TWO DEGREES OF SWIVELING FREEDOM

Abstract

A displacement device for pivoting a mirror element with two degrees of freedom of pivoting includes an electrode structure including actuator electrodes. The actuator electrodes are comb electrodes. All actuator electrodes are arranged in a single plane. The actuator electrodes form a direct drive for pivoting the mirror element.

Claims

1. A sensor device, comprising: a sensor electrode structure, comprising: a transmitter electrode having a comb structure; and a receiver electrode having a comb structure; a voltage source configured to apply AC voltage to the transmitter electrode; and a shielding unit configured to variably shield the receiver electrode from the transmitter electrode, wherein all transmitter electrodes and all receiver electrodes are arranged in a common plane, and the sensor device is configured to capture a pivot position of a mirror element having two degrees of freedom of pivoting.

2. The sensor device of claim 1, wherein the sensor device comprises a plurality of differential sensor pairs, and each sensor pair defines a measurement axis along which the pivot position of the mirror element is captured.

3. The sensor device of claim 2, comprising differential sensors which comprise capacitive comb transducers.

4. The sensor device of claim 1, wherein the shielding unit comprises constituent parts of the sensor device which are mechanically connected to a mirror body of the mirror element.

5. The sensor device of claim 1, wherein the transmitter electrode is stationary, and the receiver electrode is stationary.

6. The sensor device of claim 1, wherein the transmitter electrode defines a shielding element.

7. The sensor device of claim 1, wherein the transmitter electrode a circumferentially closed region that completely surrounds the receiver electrode in a plane.

8. A displacement device, comprising: an electrode structure comprising actuator electrodes, wherein: the actuator electrodes comprise comb electrodes; all active actuator electrodes are arranged in a single plane; the actuator electrodes define a direct drive configured to pivot a mirror element having two degrees of freedom of pivoting.

9. The displacement device of claim 8, wherein the mirror element is mounted via a Cardan-type flexure.

10. The displacement device of claim 8, wherein the actuator electrodes are arranged radially.

11. The displacement device of claim 8, wherein the electrode structure has a radial symmetry.

12. The displacement device of claim 8, wherein all active actuator electrodes are arranged in a stationary manner on a carrying structure.

13. The displacement device of claim 8, wherein the electrode structure comprises sensor electrodes arranged in the same plane as the active actuator electrodes.

14. The displacement device of claim 8, wherein at least some the active actuator electrodes are simultaneously sensor electrodes.

15. An optical component, comprising: a micromirror with two degrees of freedom of pivoting; and one of the following: a sensor device according to claim 1; or a displacement device according to claim 8 configured to displace the micromirror.

16. The optical component of claim 15, wherein the micromirror is mounted via a joint having at least two degrees of freedom of tilting.

17. The optical component of claim 16, wherein the micromirror has a centroid having a position that coincides with an effective point of rotation that is defined by the join.

18. A mirror array, comprising: a plurality of optical components, wherein, for at least some of the plurality of optical components, the optical component comprises: a micromirror with two degrees of freedom of pivoting; and one of the following: a sensor device according to claim 1; or a displacement device according to claim 8 configured to displace the micromirror.

19. An illumination optical unit, comprising: a mirror array, comprising a plurality of optical components, wherein: the illumination optical unit is configured to guide illumination radiation to an object field; and for at least some of the plurality of optical components, the optical component comprises: a micromirror with two degrees of freedom of pivoting; and one of the following: a sensor device according to claim 1; or a displacement device according to claim 8 configured to displace the micromirror.

20. An illumination system, comprising: a radiation source; and an illumination optical unit configured to guide illumination radiation to an object field, the illumination optical unit comprising a mirror array which comprises a plurality of optical components, wherein: for at least some of the plurality of optical components, the optical component comprises: a micromirror with two degrees of freedom of pivoting; and one of the following: a sensor device according to claim 1; or a displacement device according to claim 8 configured to displace the micromirror.

21. An apparatus comprising: an illumination optical unit configured to guide illumination radiation to an object field; and a projection optical unit configured to project a reticle in the object field into an image field, wherein: the apparatus is a microlithographic projection exposure apparatus; the illumination optical unit comprises a mirror array comprising a plurality of optical components, for at least some of the plurality of optical components, the optical component comprises: a micromirror with two degrees of freedom of pivoting; and one of the following: a sensor device according to claim 1; or a displacement device according to claim 8 configured to displace the micromirror.

22. A method of using a microlithographic projection exposure apparatus comprising an illumination optical unit and a projection optical unit, the method comprising: using the illumination optical unit to illuminate a reticle in an object field; and using the projection optical unit to project the reticle onto an image field, wherein: the illumination optical unit comprises a mirror array comprising a plurality of optical components, for at least some of the plurality of optical components, the optical component comprises: a micromirror with two degrees of freedom of pivoting; and one of the following: a sensor device according to claim 1; or a displacement device according to claim 8 configured to displace the micromirror.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0086] Further advantages, details and particulars of the disclosure are evident from the description of exemplary embodiments with reference to the drawings, in which:

[0087] FIG. 1 shows a schematic representation of a projection exposure apparatus and its constituent parts;

[0088] FIG. 2 shows a schematic representation of an optical component with an actuator device and a sensor device;

[0089] FIG. 3 shows an alternative representation of the optical component in accordance with FIG. 2, in which the mirror body with the counter electrodes or shielding elements arranged thereon is folded to the side;

[0090] FIG. 4 schematically shows a plan view of the section III in FIG. 3 with a schematic representation of the electrical interconnection of part of the sensor device;

[0091] FIG. 5 shows a view in accordance with FIG. 4, in which the comb fingers that are connected to the mirror body are not illustrated;

[0092] FIGS. 6 to 8 show schematic representations of a section of the sensor device for explaining the sensitivity (FIG. 6) and insensitivity (FIGS. 7 and 8) of same;

[0093] FIG. 9 shows a view of a variant of a joint for bearing an individual mirror, the joint being realized with torsion springs;

[0094] FIG. 10 shows a view of a variant of a joint for bearing an individual mirror, the joint being realized with torsion springs;

[0095] FIG. 11 shows a schematic sectional representation of the optical component in accordance with FIG. 2 for the purposes of elucidating further aspects of the actuator device and sensor device; and

[0096] FIG. 12 shows a schematic representation of a further variant of the optical component, including a counterweight in order to place the centroid of the moving mirror into the point of rotation of the joint.

DETAILED DESCRIPTION

[0097] Firstly, the general construction of a projection exposure apparatus 1 and the constituent parts thereof will be described. For details in this regard, reference should be made to WO 2010/049076 A2, which is hereby fully incorporated in the present application as part thereof. The description of the general structure of the projection exposure apparatus 1 should only be understood to be exemplary. It serves to explain a possible application of the subject matter of the present disclosure. The subject matter of the present disclosure can also be used in other optical systems, in particular in alternative variants of projection exposure apparatuses.

[0098] FIG. 1 schematically shows a microlithographic projection exposure apparatus 1 in a meridional section. An illumination system 2 of the projection exposure apparatus 1 has, besides a radiation source 3, an illumination optical unit 4 for the exposure of an object field 5 in an object plane 6. The object field 5 can be shaped in a rectangular fashion or in an arcuate fashion with an x/y aspect ratio of 13/1, for example. In this case, a reflective reticle (not illustrated in FIG. 1) arranged in the object field 5 is exposed, the reticle bearing a structure to be projected by the projection exposure apparatus 1 for the production of microstructured or nanostructured semiconductor components. A projection optical unit 7 serves for imaging the object field 5 into an image field 8 in an image plane 9. The structure on the reticle is imaged onto a light-sensitive layer of a wafer, which is not illustrated in the drawing and is arranged in the region of the image field 8 in the image plane 9.

[0099] The reticle, which is held by a reticle holder (not illustrated), and the wafer, which is held by a wafer holder (not illustrated), are scanned synchronously in the y-direction during the operation of the projection exposure apparatus 1. Depending on the imaging scale of the projection optical unit 7, it is also possible for the reticle to be scanned in the opposite direction relative to the wafer.

[0100] The radiation source 3 is an EUV radiation source having an emitted used radiation in the range of between 5 nm and 30 nm. This can be a plasma source, for example a GDPP (Gas Discharge Produced Plasma) source or an LPP (Laser Produced Plasma) source. Other EUV radiation sources, for example those based on a synchrotron or on a free electron laser (FEL), are also possible.

[0101] EUV radiation 10 emerging from the radiation source 3 is focused by a collector 11. A corresponding collector is known for example from EP 1 225 481 A2. Downstream of the collector 11, the EUV radiation 10 propagates through an intermediate focal plane 12 before being incident on a field facet mirror 13. The field facet mirror 13 is arranged in a plane of the illumination optical unit 4 which is optically conjugate with respect to the object plane 6. The field facet mirror 13 may be arranged at a distance from a plane that is conjugate to the object plane 6. In this case, it is referred to, in general, as first facet mirror.

[0102] The EUV radiation 10 is also referred to hereinafter as used radiation, illumination radiation or as imaging light.

[0103] Downstream of the field facet mirror 13, the EUV radiation 10 is reflected by a pupil facet mirror 14. The pupil facet mirror 14 lies either in the entrance pupil plane of the projection optical unit 7 or in an optically conjugate plane with respect thereto. It may also be arranged at a distance from such a plane.

[0104] The field facet mirror 13 and the pupil facet mirror 14 are constructed from a multiplicity of individual mirrors, which will be described in even greater detail below. In this case, the subdivision of the field facet mirror 13 into individual mirrors can be such that each of the field facets which illuminate the entire object field 5 by themselves is represented by exactly one of the individual mirrors. Alternatively, it is possible to construct at least some or all of the field facets using a plurality of such individual mirrors. The same correspondingly applies to the configuration of the pupil facets of the pupil facet mirror 14, which are respectively assigned to the field facets and which can be formed in each case by a single individual mirror or by a plurality of such individual mirrors.

[0105] The EUV radiation 10 impinges on both facet mirrors 13, 14 at a defined angle of incidence. In particular, the two facet mirrors are impinged with EUV radiation 10 in the range associated with normal incidence operation, i.e. with an angle of incidence that is less than or equal to 25° in relation to the mirror normal. Impingement with grazing incidence is also possible. The pupil facet mirror 14 is arranged in a plane of the illumination optical unit 4 which constitutes a pupil plane of the projection optical unit 7 or is optically conjugate with respect to a pupil plane of the projection optical unit 7. With the aid of the pupil facet mirror 14 and an imaging optical assembly in the form of a transfer optical unit 15 having mirrors 16, 17 and 18 designated in the order of the beam path for the EUV radiation 10, the field facets of the field facet mirror 13 are imaged into the object field 5 in a manner being superimposed on one another. The last mirror 18 of the transfer optical unit 15 is a mirror for grazing incidence (“grazing incidence mirror”). The transfer optical unit 15 together with the pupil facet mirror 14 is also referred to as a sequential optical unit for transferring the EUV radiation 10 from the field facet mirror 13 toward the object field 5. The illumination light 10 is guided from the radiation source 3 toward the object field 5 via a plurality of illumination channels. Each of these illumination channels is assigned a field facet of the field facet mirror 13 and a pupil facet of the pupil facet mirror 14, the pupil facet being disposed downstream of the field facet. The individual mirrors of the field facet mirror 13 and of the pupil facet mirror 14 can be tiltable by an actuator system, such that a change in the assignment of the pupil facets to the field facets and correspondingly a changed configuration of the illumination channels can be achieved. This results in different illumination settings, which differ in the distribution of the illumination angles of the illumination light 10 over the object field 5.

[0106] In order to facilitate the explanation of positional relationships, use is made below of, inter alia, a global Cartesian xyz-coordinate system. The x-axis runs perpendicular to the plane of the drawing toward the observer in FIG. 1. The y-axis runs toward the right in FIG. 1. The z-axis runs upward in FIG. 1.

[0107] Different illumination systems can be achieved via a tilting of the individual mirrors of the field facet mirror 13 and a corresponding change in the assignment of the individual mirrors of the field facet mirror 13 to the individual mirrors of the pupil facet mirror 14. Depending on the tilting of the individual mirrors of the field facet mirror 13, the individual mirrors of the pupil facet mirror 14 that are newly assigned to the individual mirrors are tracked by tilting such that an imaging of the field facets of the field facet mirror 13 into the object field 5 is once again ensured.

[0108] Further aspects of the illumination optical unit 4 are described below.

[0109] The one field facet mirror 13 in the form of a multi- or micro-mirror array (MMA) forms an example of an optical assembly for guiding the used radiation 10, that is to say the EUV radiation beam. The field facet mirror 13 is formed as a microelectromechanical system (MEMS). It has a multiplicity of individual mirrors 20 arranged in a matrix-like manner in rows and columns in a mirror array 19. The mirror arrays 19 are embodied in a modular manner. They can be arranged on a carrying structure that is embodied as a base plate. Here, it is possible to arrange essentially any number of the mirror arrays 19 next to one another. Consequently, the overall reflection surface which is formed by the totality of all mirror arrays 19, in particular the individual mirrors 20 thereof, is extendable as desired. In particular, the mirror arrays are embodied in such a way that they facilitate a substantially gap-free tessellation of a plane. The ratio of the sum of the reflection surfaces 26 of the individual mirrors 20 to the overall area that is covered by mirror arrays 19 is also referred to as integration density. In particular, this integration density is at least 0.5, in particular at least 0.6, in particular at least 0.7, in particular at least 0.8, in particular at least 0.9.

[0110] The mirror arrays 19 are fixed onto the base plate via fixing elements 29. For details, reference is made to e.g. WO 2012/130768 A2.

[0111] The individual mirrors 20 are designed to be tiltable by an actuator system, as will be explained below. Overall, the field facet mirror 13 has approximately 100 000 of the individual mirrors 20. The field facet mirror 13 may also have a different number of individual mirrors 20 depending on the size of the individual mirrors 20. The number of individual mirrors 20 of the field facet mirror 13 is in particular at least 1000, in particular at least 5000, in particular at least 10 000. It can be up to 100 000, in particular up to 300 000, in particular up to 500 000, in particular up to 1 000 000.

[0112] A spectral filter can be arranged upstream of the field facet mirror 13 and separates the used radiation 10 from other wavelength components of the emission of the radiation source 3 that are not usable for the projection exposure. The spectral filter is not represented.

[0113] The field facet mirror 13 is impinged on by used radiation 10 having a power of e.g. 840 W and a power density of 6.5 kW/m.sup.2.

[0114] The entire individual mirror array of the facet mirror 13 has e.g. a diameter of 500 mm and is designed in a closely packed manner with the individual mirrors 20. In so far as a field facet is realized by exactly one individual mirror in each case, the individual mirrors 20 represent the shape of the object field 5, apart from the scaling factor. The facet mirror 13 can be formed from 500 individual mirrors 20 each representing a field facet and having a dimension of approximately 5 mm in the y-direction and 100 mm in the x-direction. As an alternative to the realization of each field facet by exactly one individual mirror 20, each of the field facets can be approximated by groups of smaller individual mirrors 20. A field facet having dimensions of 5 mm in the y-direction and of 100 mm in the x-direction can be constructed e.g. via a 1×20 array of individual mirrors 20 having dimensions of 5 mm×5 mm through to a 10×200 array of individual mirrors 20 having dimensions of 0.5 mm×0.5 mm.

[0115] The tilt angles of the individual mirrors 20 are adjusted for changing the illumination settings. In particular, the tilt angles have a displacement range of ±50 mrad, in particular ±100 mrad. An accuracy of better than 0.2 mrad, in particular better than 0.1 mrad, is achieved when setting the tilt position of the individual mirrors 20.

[0116] The individual mirrors 20 of the field facet mirror 13 and of the pupil facet mirror 14 in the embodiment of the illumination optical unit 4 according to FIG. 1 bear multilayer coatings for optimizing their reflectivity at the wavelength of the used radiation 10. The temperature of the multilayer coatings should not exceed 425 K during the operation of the projection exposure apparatus 1. This is achieved by a suitable structure of the individual mirrors 20. For details, reference is made to DE 10 2013 206 529 A1, which is hereby fully incorporated into the present application.

[0117] The individual mirrors 20 of the illumination optical unit 4 are accommodated in an evacuable chamber 21, a boundary wall 22 of which is indicated in FIGS. 2 and 6. The chamber 21 communicates with a vacuum pump 25 via a fluid line 23, in which a shutoff valve 24 is accommodated. The operating pressure in the evacuable chamber 21 is a few pascals, in particular 3 Pa to 5 Pa (partial pressure H.sub.2). All other partial pressures are significantly below 1×10.sup.−7 mbar.

[0118] Together with the evacuable chamber 21, the mirror having the plurality of individual mirrors 20 forms an optical assembly for guiding a bundle of the EUV radiation 10.

[0119] Each of the individual mirrors 20 can have a reflection surface 26 having dimensions of 0.1 mm×0.1 mm, 0.5 mm×0.5 mm, 0.6 mm×0.6 mm, or else of up to 5 mm×5 mm or larger. The reflection surface 26 can also have smaller dimensions. In particular, it has side lengths in the μm range or low mm range. The individual mirrors 20 are therefore also referred to as micromirrors. The reflection surface 26 is part of a mirror body 27 of the individual mirror 20. The mirror body 27 carries the multilayer coating.

[0120] With the aid of the projection exposure apparatus 1, at least one part of the reticle is imaged onto a region of a light-sensitive layer on the wafer for the lithographic production of a micro- or nanostructured component, in particular of a semiconductor component, e.g. of a microchip. Depending on the embodiment of the projection exposure apparatus 1 as a scanner or as a stepper, the reticle and the wafer are moved in a temporally synchronized manner in the y-direction continuously in scanner operation or step by step in stepper operation.

[0121] Further details and aspects of the mirror array 19, in particular of the optical components which include the individual mirrors 20, are described below.

[0122] Initially, a first variant of an optical component 30 including an individual mirror 20 and, in particular, the displacement device 31 for displacing, in particular for pivoting, the individual mirror 20 is described with reference to FIGS. 2 to 5.

[0123] The representation in accordance with FIG. 3 corresponds to that in accordance with FIG. 2, with the mirror body 27 of the individual mirror 20 being folded away to the side in FIG. 3. As a result, the structures of the displacement device 31 and of the sensor device are better visible.

[0124] FIG. 4 shows a sectional representation of a section parallel to the actuator plane 40 of the section IV of the optical component 30 in accordance with FIG. 3.

[0125] The optical component includes the individual mirror 20 which, in particular, is embodied as a micromirror. The individual mirror 20 includes the mirror body 27 described above, on the front side of which the reflection surface 26 is formed. In particular, the reflection surface 26 is formed by a multilayer structure. In particular, it has a radiation reflecting property for the illumination radiation 10, in particular for EUV radiation.

[0126] In accordance with the variant represented in the figures, the reflection surface 26 has a square embodiment; however, it is represented in a partly cut manner in order also to show the actuator system. It generally has a rectangular embodiment. It can also have a triangular or hexagonal embodiment. In particular, it has such a tile-like embodiment that a gap-free tessellation of a plane by way of the individual mirrors 20 is possible. The individual mirror 20 is mounted via a joint 32 that will still be described in more detail below. In particular, it is mounted in such a way that it has two degrees of freedom of tilting. In particular, the joint 32 facilitates the tilt of the individual mirror 20 about two tilt axes 33, 34. The tilt axes 33, 34 are perpendicular to one another. They intersect at a central point of intersection, which is referred to as effective pivot point 35.

[0127] To the extent that the individual mirror 20 is in a non-pivoted neutral position, the effective pivot point 35 lies on a surface normal 36 which extends through a central point, in particular the geometric centroid of the reflection surface 26.

[0128] To the extent that nothing else is specified, the direction of the surface normal 36 in the following text is always understood to mean the direction of same in the non-tilted neutral position of the individual mirror 20.

[0129] Firstly, the displacement device 31 is described in greater detail below.

[0130] The displacement device 31 includes an electrode structure including actuator transducer stator electrodes 37.sub.i and actuator transducer mirror electrodes 42. In accordance with the variant illustrated in FIGS. 2 to 5, the electrode structure includes four actuator transducer stator electrodes 37.sub.1, 37.sub.2, 37.sub.3, and 37.sub.4. In general, the number of actuator transducer stator electrodes 37.sub.i is at least 2. It may be 3, 4 or more.

[0131] All actuator transducer electrodes 37.sub.i, 42 are embodied as comb electrodes including a plurality of comb fingers 38. The respectively complementary comb fingers of the mirror and stator engage in one another in this case. The combs of the individual actuator electrodes 37.sub.i in each case include 30 actuator transducer stator comb fingers 38, which are also abbreviated as stator comb fingers or merely as comb fingers below. A respectively different number is likewise possible. The number of the comb fingers 38 of the actuator transducer stator electrodes 37.sub.i is, in particular, at least 2, in particular at least 3, in particular at least 5, in particular at least 10. It can be up to 50, in particular up to 100.

[0132] The combs of the actuator transducer mirror electrodes 42 accordingly include actuator transducer mirror comb fingers 43, which are also abbreviated as mirror comb fingers or merely as comb fingers below. The number of the mirror comb fingers 43 corresponds to the number of the stator comb fingers. It may also deviate by one from the number of stator comb fingers in each case.

[0133] The comb fingers 38 are arranged in such a way that they extend in the radial direction in relation to the surface normal 36 or the effective pivot point 35. In accordance with a variant that is not illustrated in the figures, the comb fingers 38, 43 may also be arranged tangentially to circles around the effective pivot point 35. They may also have an embodiment which corresponds to sections of concentric circular cylinder lateral surfaces around the surface normal 36.

[0134] All of the actuator transducer stator electrodes 37.sub.i are arranged on a carrying structure in the form of a substrate 39. In particular, they are arranged on the substrate 39 in a stationary manner. In particular, they are arranged in a single plane that is defined by the front side of the substrate 39. This plane is also referred to as actuator plane 40 or as comb plane.

[0135] In particular, a wafer serves as a substrate 39. The substrate 39 is also referred to as base plate.

[0136] The actuator transducer stator electrodes 37.sub.i are respectively arranged in a region on the substrate 39 which, firstly, has a square outer contour and, secondly, a circular inner contour. As an alternative thereto, the actuator transducer stator electrodes 37.sub.i may also be arranged in a circular-ring-shaped region on the substrate 39. Here, the outer contour also has a circular embodiment. In particular, the individual actuator transducer stator electrodes 37.sub.i are respectively arranged in circular-ring-segment-shaped regions. The electrode structure overall, i.e. all actuator transducer stator electrodes 37i, is arranged in a region which has an outer contour that, to all intents and purposes, corresponds to that of the reflection surface of the individual mirror 20. It may also be arranged in a slightly smaller region, in particular a region that is smaller by approximately 5% to 25%.

[0137] The electrode structure has radial symmetry. In particular, it has a fourfold radial symmetry. The electrode structure may also have a different radial symmetry. In particular, it may have a threefold radial symmetry. In particular, it has a k-fold radial symmetry, where k specifies the number of actuator transducer stator electrodes 37.sub.i. Apart from the subdivision of the electrode structure into the different actuator transducer stator electrodes 37.sub.i, the electrode structure has an n-fold radial symmetry, where n precisely corresponds to the overall number of comb fingers 38 of all actuator transducer stator electrodes 37.sub.i.

[0138] Apart from their different arrangement on the substrate 39, the individual actuator transducer stator electrodes 37.sub.i have an identical embodiment. This is not absolutely necessary. They can also have a different embodiment. In particular, they may be embodied depending on the mechanical properties of the joint 32.

[0139] The comb fingers 38 are arranged radially in relation to the effective pivot point 35, or radially in relation to the alignment of the surface normal 36 in the non-pivoted neutral state of the individual mirror 20.

[0140] In the case of individual mirrors 20, the mirror bodies 27 of which have dimensions of 1 mm.Math.1 mm, the comb fingers 38 have a thickness d of at most 5 μm at their outer end in the radial direction. In general, the maximum thickness d of the comb fingers 38 at their outer end in the radial direction lies in the range of 1 μm to 20 μm, in particular in the range of 3 μm to 10 μm.

[0141] The comb fingers 38 have a height h, i.e. an extent in the direction of the surface normal 36, which is in the range of 10 μm to 100 μm, in particular in the range of 20 μm to 50 μm. Other values are likewise conceivable. The height h is constant in the radial direction. It may also decrease in the radial direction. This can facilitate larger tilt angles, without this leading to the comb fingers of the actuator mirror electrode 42 impacting on the base plate.

[0142] Adjacent comb fingers 38, 43 of the actuator electrodes 37.sub.i on the one hand and of the actuator mirror electrodes 42 on the other hand have a minimum spacing in the range of 1 μm to 10 μm, in particular in the range of 3 μm to 7 μm, in particular approximately 5 μm, in the non-pivoted state of the individual mirror 20. These values can be scaled appropriately for individual mirrors 20 with smaller or larger dimensions.

[0143] This minimum spacing m is the minimum distance between adjacent mirror comb fingers and stator comb fingers, measured in the neutral, non-pivoted state of the individual mirror 20. The comb fingers may approach one another when the individual mirror 20 is tilted. The minimum spacing m is selected in such a way that there is no collision between adjacent mirror comb fingers and stator comb fingers, even in the case of the maximum tilt of the individual mirror 20. Here, manufacturing tolerances have also been taken into account. Such manufacturing tolerances are a few micrometers, in particular at most 3 μm, in particular at most 2 μm, in particular at most 1 μm.

[0144] The maximum possible approach of adjacent comb fingers 38, 43 can easily be determined from the geometric details of the same and the arrangement thereof, and the maximum possible tilt of the individual mirror 20. In the present embodiment, the maximum approach of adjacent comb fingers 38, 43 is approximately 2 μm in the case of a tilt of the individual mirror 20 by 100 mrad. In particular, the maximum approach is less than 10 μm, in particular less than 7 μm, in particular less than 5 μm, in particular less than 3 μm.

[0145] The actuator transducer stator electrodes 37.sub.i respectively interact with an actuator mirror electrode 42. The actuator mirror electrode 42 is connected to the mirror body 27. In particular, the actuator mirror electrode 42 is connected in a mechanically secured manner to the mirror body 27. The actuator transducer mirror electrodes 42 form a counter electrode to the actuator transducer stator electrodes 37.sub.i. Therefore, they are also simply referred to as counter electrode.

[0146] The actuator mirror electrode 42 forms a passive electrode structure. This should be understood to mean that the actuator mirror electrode 42 has a fixed, constant voltage applied thereto.

[0147] The actuator mirror electrode 42 has a complementary embodiment to the actuator transducer stator electrodes 37.sub.i. In particular, it forms a ring with actuator transducer mirror comb fingers 43, which, for simplification purposes, are also referred to as mirror comb fingers or only as comb fingers 43 below. In terms of their geometric properties, the mirror comb fingers 43 of the actuator mirror electrode 42 substantially correspond to the stator comb fingers 38 of the actuator transducer stator electrodes 37.sub.i.

[0148] All comb fingers 38, 43 may have the same height, i.e. identical dimensions in the direction of the surface normal 36. This simplifies the production process.

[0149] In the direction of the surface normal 36, the mirror comb fingers 43 of the actuator mirror electrode 42 may also have a different height to that of the stator comb fingers 38 of the active actuator transducer stator electrodes 37.sub.i.

[0150] The comb fingers 38, 43 may have a height h that decreases in the radial direction. It is also possible to embody the comb fingers 38, 43 in the region of the corners of the optical component 30 to be shorter than the remaining comb fingers 38, 43. This can facilitate a greater tilt angle of the individual mirror 20.

[0151] In particular, the actuator mirror electrode 42 is embodied in such a way that in each case one of the comb fingers 43 of the actuator mirror electrode 42 is able to be immersed in an interstice between two of the comb fingers 38 of the actuator transducer stator electrodes 37.sub.i.

[0152] The actuator mirror electrode 42 is connected to the mirror body 27 in an electrically conductive manner. Therefore, their comb fingers 43 are equipotential. The mirror body 27 has a low resistance connection to the base plate by way of an electrically conductive joint spring. In principle, it is also possible to individually electrically connect the mirror substrate, i.e. the mirror body 27, the actuator mirror electrodes 42 and the sensor mirror electrodes 45, by way of separate supply lines via the flexure 32 and thus, for example, put these at different potentials or decouple these in respect of faults and/or crosstalk. The base plate may be grounded, but this need not be the case. Alternatively, the mirror can be connected to a voltage source at a different potential by way of a conductive joint spring, but be electrically isolated from the mirror plate. As a result of this, it is possible to apply a fixed or variable bias voltage to the mirror.

[0153] An actuator voltage U.sub.A can be applied to the actuator transducer stator electrodes 37.sub.i for pivoting the individual mirror 20. Therefore, the actuator transducer stator electrodes 37.sub.i are also referred to as active actuator transducer stator electrodes 37.sub.i. A voltage source that is not depicted in the figures is provided for applying the actuator voltage U.sub.A to the actuator transducer stator electrodes 37i. The actuator voltage U.sub.A is at most 200 volts, in particular at most 100 volts. By suitably applying the actuator voltage U.sub.A to a selection of the actuator transducer stator electrodes 37.sub.i, the individual mirror 20 can be tilted by up to 50 mrad, in particular up to 100 mrad, in particular up to 150 mrad, from a neutral position. Alternatively, the actuators can also be actuated by a charge source (current source).

[0154] Different actuator voltages U.sub.Ai can be applied to the various actuator transducer stator electrodes 37.sub.i for pivoting the individual mirror 20. A control device that is not illustrated in the figures is provided for controlling the actuator voltages U.sub.Ai.

[0155] For the purposes of tilting one of the individual mirrors 20, an actuator voltage U.sub.A is applied to one of the actuator transducer stator electrodes 37.sub.i. At the same time, an actuator voltage U.sub.A2≠U.sub.A1 deviating therefrom is applied to the actuator transducer stator electrode 37.sub.j that lies opposite thereto in relation to the surface normal 36. Here, U.sub.A2 may=0 volts. In particular, it is possible to apply the actuator voltage U.sub.A1 to only one of the actuator transducer stator electrodes 37.sub.i, while all other actuator transducer stator electrodes 37.sub.j are kept at a voltage of 0 volts.

[0156] When the individual mirror 20 is tilted, the comb fingers of the actuator mirror electrode 47 are immersed more deeply between the comb fingers 38 of the actuator transducer stator electrode 37.sub.i on one side, in particular in the region of this actuator transducer stator electrode 37.sub.i to which the actuator voltage U.sub.A has been applied. On the opposite side of the tilt axis 33, the actuator mirror electrode 42 is immersed less deeply into the actuator transducer stator electrodes 37.sub.j. The actuator mirror electrode 42 may even emerge from the actuator transducer stator electrodes 37.sub.j, at least in regions.

[0157] The comb overlap, i.e. the immersion depth of the actuator mirror electrode 42 between the actuator transducer stator electrodes 37.sub.i, is 30 μm in the neutral position of the individual mirror 20 in the case of a mirror dimension of approximately 0.5 mm×0.5 mm.

[0158] In the neutral position there is a maximum reduction of the distance between the comb fingers 43 of the actuator mirror electrode 42 and the comb fingers 38 of the actuator transducer stator electrodes 37.sub.i of 1.1 μm in the case of a tilt of the mirror 20 by 100 mrad. Consequently, the comb fingers 43 of the actuator mirror electrode 42 and the comb fingers 38 of the actuator transducer stator electrodes 37.sub.i are spaced apart from one another, in particular without contact, in every pivot position of the mirror 20. In particular, the immersion depth, i.e. the comb overlap, is selected in such a way that this is ensured.

[0159] In accordance with an alternative, the comb fingers 38, 43 are slightly shorter in the outer region and therefore have a relatively small overlap, i.e. a shallower immersion depth. By way of example, the immersion depth in the outermost region may be approximately half as deep as the immersion depth in the inner region. These specifications also relate to the neutral position of the mirror 20.

[0160] By way of a dependence of the immersion depth of the comb fingers 38, 43 on the radial position thereof, it is also possible to influence the characteristic, in particular the linearity of the actuation. Since all of the actuator transducer stator electrodes 37.sub.i are arranged in a single plane, the actuator plane 40, it is possible to dispense with complicated series kinematics. The displacement device 31 is distinguished by parallel kinematics. In particular, the displacement device 31 has no movably arranged active components. All of the actuator transducer stator electrodes 37.sub.i, to which the actuator voltage U.sub.A can be applied, are arranged in an immovable stationary manner on the substrate 39. A sensor device is provided for capturing the pivot position of the individual mirror 20. The sensor device may form a constituent part of the displacement device 31.

[0161] The sensor device includes sensor transducer mirror electrodes 45 and sensor transducer stator electrodes 44.sub.i.

[0162] The sensor unit includes four sensor transducer stator electrodes 44.sub.1 to 44.sub.4. For simplification purposes, the sensor transducer stator electrodes 44.sub.i are also referred to only as sensor electrodes. For the actuation, it is advantageous if the number of sensor transducer stator electrodes 44.sub.i precisely corresponds to the number of actuator transducer stator electrodes 37.sub.i. However, the number of sensor transducer stator electrodes 44.sub.i can also deviate from the number of actuator transducer stator electrodes 37.sub.i.

[0163] The sensor transducer stator electrodes 44.sub.1 to 44.sub.4 are respectively arranged along the diagonal of the substrate 39 in the variant in accordance with FIGS. 2 to 5. In the variant illustrated in FIGS. 2 to 5, the sensor transducer stator electrodes 44.sub.1 to 44.sub.4 are arranged with a 45° offset relative to the tilt axes 33, 34 of the joint 32.

[0164] The actuator transducer stator electrodes 37.sub.1 are respectively arranged in quadrants 54.sub.1 to 54.sub.4 on the substrate 39. The sensor transducer stator electrodes 44.sub.1 are respectively arranged in the same quadrant 54.sub.1 to 54.sub.4 as respectively one of the actuator transducer stator electrodes 37.sub.i. The actuator device 31, in particular the arrangement and embodiment of the actuator transducer stator electrodes 37.sub.i, has substantially the same symmetry properties as the reflection surface 26 of the individual mirror 20. The sensor device, in particular the sensor transducer stator electrodes 44.sub.i, has substantially the same symmetry properties as the reflection surface 26 of the individual mirror 20.

[0165] Respectively two sensor transducer stator electrodes 44.sub.i that lie opposite one another in respect of the effective pivot point 35 are interconnected in a differential manner. However, such an interconnection is not mandatory. In general, it is advantageous if respectively two sensor electrodes 44.sub.i that lie opposite one another in respect of the effective pivot point 35 are embodied and arranged in such a way that they can be read in a differential manner.

[0166] The sensor transducer stator electrodes 44.sub.i are embodied as comb electrodes. In particular, the sensor transducer stator electrodes 44.sub.i can be embodied in a manner corresponding to the actuator transducer stator electrodes 37.sub.i, with reference herewith being made to the description thereof. The sensor transducer stator electrodes 44.sub.i each include a sensor transducer stator transmitter electrode 47, which is also abbreviated as transmitter electrode below, and a sensor transducer stator receiver electrode 48, which is also abbreviated as receiver electrode below. Both the sensor transducer stator transmitter electrode 47 and the sensor transducer stator receiver electrode 48 have a comb structure. In particular, they include a plurality of comb fingers. In particular, the comb fingers of the sensor transducer stator transmitter electrode 47 are arranged in alternation with the comb fingers of the sensor transducer stator receiver electrode 48.

[0167] The sensor device includes a sensor transducer mirror electrode 45 for each of the sensor transducer stator electrodes 44.sub.i. In accordance with an advantageous embodiment, the sensor transducer mirror electrodes 45 each form a shielding unit of the sensor transducer stator electrodes 44.sub.i. The sensor transducer mirror electrode 45 in each case includes comb elements with a plurality of comb fingers 46. The sensor transducer mirror electrode 45 is embodied in accordance with a counter electrode fitting to the sensor transducer stator electrodes 44.sub.i. In particular, the sensor transducer mirror electrodes 45 can be embodied in a manner corresponding to the actuator transducer mirror electrodes 42, with reference herewith being made to the description thereof.

[0168] The sensor transducer mirror electrodes 45 are respectively connected in a secured manner to the mirror body 27. They are arranged in the region of the diagonal of the mirror body 27. When the individual mirror 20 is tilted, the sensor transducer mirror electrode 45 can respectively be immersed to a different depth between the comb fingers of the sensor transducer stator electrodes 44.sub.k, in particular between the transmitter electrode 47 and the receiver electrode 48. As a result of this, there is a variable shielding of adjacent comb fingers, in particular a variable shielding of the receiver electrode 48 from the transmitter electrode 47. This leads to a change in the capacitance between the adjacent comb fingers of the sensor transducer stator electrodes 44.sub.i when the individual mirror 20 is pivoted. This change in capacitance can be measured. To this end, the inputs of a measuring appliance are alternately connected with the comb fingers of the sensor transducer stator electrodes 44.sub.k, as is illustrated schematically in FIG. 4.

[0169] The immersion depth of the sensor transducer mirror electrodes 45 between the sensor transducer stator electrodes 44.sub.k, in particular between the transmitter electrodes 47 and the receiver electrodes 48, is 30 μm. This ensures that the comb fingers 46 still have a residual immersion depth everywhere between the transmitter electrodes 47 and the receiver electrodes 48, even in the maximally tilted pivot position, i.e. they never completely emerge. This ensures the differential sensor operation over the entire tilt range. On the other hand, the immersion depth of the sensor transducer mirror electrode 45 is selected in such a way that there is no collision of same with the substrate 39, even in the maximally tilted pivot position of the individual mirror 20.

[0170] An electric voltage, in particular a sensor voltage U.sub.s, is applied to the transmitter electrode 47 for the purposes of measuring the capacitance between the transmitter electrode 47 and the receiver electrode 48 of the sensor transducer stator electrodes 44.sub.i. In particular, an AC voltage serves as a sensor voltage U.sub.s.

[0171] The sensor device is sensitive in view of the immersion depth of the comb fingers 46 between adjacent comb fingers of the sensor transducer stator electrodes 44.sub.i (FIG. 6).

[0172] The sensor device is insensitive in relation to pure pivoting of the comb finger 46 relative to the transmitter electrode 47 and the receiver electrode 48 (FIG. 7).

[0173] The sensor device is insensitive in relation to a lateral displacement of the shielding element which changes the distance of same from the transmitter electrode 47 and from the receiver electrode 48 but leaves the immersion depth of the comb finger 46 between the adjacent transmitter and receiver electrodes 47, 48 unchanged (FIG. 8).

[0174] Further details of the sensor device are described more closely below.

[0175] The sensor transducer stator electrodes 44.sub.i are arranged within the ring of the actuator transducer stator electrodes 37.sub.i. In this region, the absolute movements of the comb fingers 46 in the direction parallel to the surface normal 36 are less than outside of the ring of the actuator transducer stator electrodes 37.sub.i. The absolute scope of movement is related to the distance from the effective pivot point 35.

[0176] In the embodiments illustrated in the figures, the sensor transducer stator electrodes 44.sub.i protrude inwardly in the radial direction beyond the inner contour of the actuator transducer stator electrodes 37.sub.i. It is also possible to embody the sensor transducer stator electrodes 44.sub.i in such a way that they do not protrude beyond the inner contour of the actuator transducer stator electrodes 37.sub.i.

[0177] The sensor transducer stator electrodes 44.sub.i are embodied and arranged radially relative to the effective pivot point 35. In particular, they have comb fingers that extend in the radial direction. This reduces the sensitivity in relation to a possible thermal expansion of the individual mirror 20.

[0178] As already explained above, on account of its structure, the sensor device has, at best, a minimal sensitivity in view of parasitic movements of the individual mirror 20, in particular in view of displacements perpendicular to the surface normal 36 and/or rotations about the surface normal 36. On account of the shielding principle of the sensor device, the latter also has, at best, a minimal sensitivity in view of a possible thermal expansion of the individual mirror 20. Moreover, the sensor principle has a minimal sensitivity in view of thermal bending of the mirror.

[0179] Respectively two sensor units that lie opposite one another in respect of the effective pivot point 35, each with a transmitter electrode 47 and a receiver electrode 48, are interconnected in a differential manner or at least readable in a differential manner. This renders it possible to eliminate errors in the measurement of the position of the mirror 20, in particular on account of eigenmodes of the individual mirror 20.

[0180] The active constituent parts of the sensor device are arranged on the substrate 39. This renders it possible to measure the tilt angle of the individual mirror 20 directly relative to the substrate 39. Moreover, the length of the signal line 56 and/or of the supply lines 57 can be reduced, in particular minimized, on account of the arrangement of the transmitter electrodes 47 and the receiver electrodes 48 on the substrate 39. This reduces possible disturbing influences. This ensures constant operating conditions.

[0181] The transmitter electrodes 47 are respectively embodied as active shielding, in particular as a shielding ring, about the receiver electrodes 48. This reduces, in particular minimizes, in particular prevents capacitive crosstalk between the actuator transducer stator electrodes 37.sub.i and the sensor device.

[0182] As indicated schematically in FIG. 4, an AC voltage is applied to the transmitter electrode 47 from a voltage source 48. The voltage source 58 has a low impedance. In particular, the voltage source 58 has an output impedance which, in the region of the excitation frequency, is less than 1 part in a thousand of the coupling capacitances from the actuator transducer stator electrodes 37.sub.i to the transmitter electrodes 47. The output impedance of the voltage source is less than 1 part in a thousand of the capacitances between the transmitter electrodes 47 and the sensor transducer mirror electrodes 45 or the receiver electrodes 48. This ensures that the AC voltage that is applied to the transmitter electrodes 47 is not influenced, or at least not substantially influenced, by the variable actuator voltages U.sub.A or by the variable sensor capacitance.

[0183] In general, a network analyzer can be used for reading the sensor transducer. Using this, it is possible to determine the impedance of the sensor transducer and, therefrom, determine the displacement position of the individual mirror 20 via a conversion factor. Such a network analyzer generally includes an excitation source, for example the voltage source 58 described above, and a response measurement, for example a current measurement or a measurement of the charge transported during a signal period. The network impedance and hence the sensor capacitance can be determined from the quotient of excitation voltage and current.

[0184] Two variants of the joint 32 are described in greater detail below with reference to FIGS. 9 and 10.

[0185] The joint 32 is embodied as a Cardan-type flexure.

[0186] In accordance with a variant illustrated in FIG. 9, the joint 32 is embodied as a torsion spring element structure. In particular, it includes two torsion springs 50, 51. The two torsion springs 50, 51 have an integral embodiment. In particular, they are aligned perpendicular to one another and form a cross-shaped structure 49.

[0187] The torsion springs 50, 51 have a length of approximately 100 μm, a width of approximately 60 μm, and a thickness of approximately 1 μm to 5 μm. Such torsion springs 50, 51 are suitable as individual mirrors 20 with dimensions of 0.6 mm-0.6 mm. The dimensions of the torsion springs 50, 51 depend on the dimensions of the individual mirrors 20. In general, larger mirrors involve larger, in particular stiffer torsion springs 50, 51.

[0188] The torsion spring 50 extends in the direction of the tilt axis 33. The torsion spring 50 is mechanically connected to the substrate 39. Connecting blocks 52 serve to connect the torsion spring 50 to the substrate 39. The connecting blocks 52 in each case have a cuboid embodiment. They can also have a cylindrical, in particular circular-cylindrical embodiment. Other geometric forms are likewise possible.

[0189] The connecting blocks 52 are respectively arranged in an end region of the torsion spring 50.

[0190] In addition to the connection of the joint 32 to the substrate 39, the connecting blocks 52 also server as spacers between the torsion spring 50 and the substrate 39.

[0191] In a manner corresponding to the connection of the torsion spring 50 to the substrate 39, the torsion spring 51 is mechanically connected to the mirror body 27 of the individual mirror 20, which is not illustrated in FIG. 9. Connecting blocks 53 are provided to this end. In terms of their embodiment, the connecting blocks 53 correspond to the connecting blocks 52. The connecting blocks 53 are respectively arranged in an end region of the torsion spring 51.

[0192] In the direction of the surface normal 36, the connecting blocks 53 and the connecting blocks 52 are arranged on opposite sides of the cross-shaped structure 49.

[0193] The torsion springs 50, 51 of the joint 32 have a T-shaped profile in the region of the limbs of the cross-shaped structure 49 that adjoins the central region. As a result of this, the torsion springs 50, 51 are stiffened, in particular in relation to deflections in the direction of the surface normal 36. What this achieves is that the natural frequency of the mirror 20 in the vertical direction is shifted to high frequencies, and hence a mode separation of the regulated tilt modes and the parasitic vertical vibration mode of more than one decade in frequency space is obtained, which is advantageous from a control theory point of view. Moreover, the thermal conductivity of the joint 32 can be increased by way of the cross-shaped stiffening element 55.

[0194] In principle, it is possible to arrange a corresponding stiffening element 55 on the opposite side of the cross-shaped structure 49 as well. In this case, the limbs of the torsion springs 50, 51 have a cross-shaped cross section.

[0195] The mechanical and/or thermal properties of the joint can be influenced in a targeted manner by way of a targeted design of the stiffening elements 55. The profile, in particular the stiffening elements 55, serves to increase the stiffness in the actuator plane. In particular, they serve to realize a binding stiffness of the individual mirror 20 in relation to the base plate 39 in the horizontal degrees of freedom, i.e. in a horizontal displacement and a rotation about the vertical axis. As a result of this, the natural frequencies of the parasitic modes of the individual mirror 20 are increased. This obtains a mode spacing of the actuated tilt modes and the parasitic modes that is advantageous from a control theory point of view. In particular, the natural frequencies of the parasitic modes preferably lie at least one decade above the actuated tilt modes.

[0196] Moreover, the forces acting between the mirror 20 and the actuator transducer stator comb fingers 38 and the electrostatic softening (negative stiffness) arising as a result thereof are absorbed by the high horizontal stiffness. In particular, it is possible to ensure that there is no transversal pull-in from the view of the comb fingers 38.

[0197] The stiffening elements 55, which are also referred to as stiffening ribs, in particular as perpendicular stiffening ribs, serve to shift the deflection stiffness and hence shift the natural frequency of vertical vibrations, i.e. vibrations in the direction of the surface normal 36, to higher frequencies.

[0198] The joint 32 is stiff in view of rotations about the surface normal 36. The joint 32 is stiff in view of the linear displacement in the direction of the surface normal 36. In this context, stiff means that the natural frequency of the rotational vibrations about the surface normal 36 and the natural frequency of the vibrations in the direction of the surface normal lie above the actuated modes by more than one frequency decade. The actuated tilt modes of the individual mirror lie, in particular, at frequencies below 1 kHz, in particular below 600 Hz. The natural frequency of the rotational vibrations about the surface normal 36 lies at more than 10 kHz, in particular at more than 30 kHz.

[0199] The joint 32 has a known flexibility in view of pivoting about the two tilt axes 33, 34. The stiffness of the joint 32 in view of pivoting about the tilt axes 33, 34 can be influenced by a targeted embodiment of the torsion springs 50, 51.

[0200] The joint 32, in particular the connecting blocks 52, 53 and the torsion springs 50, 51, serve to dissipate heat from the mirror body 27. The constituent parts of the joint 32 form thermal conduction sections.

[0201] The joint 32 including the connecting blocks 52, 53 has a plurality of functions. Firstly: binding the non-actuated degrees of freedom, secondly, heat transport from the mirror 20 to the base plate 39; and, thirdly, the electrical connection between the mirror 20 and the base plate 39. The purpose of the blocks 52, 53 is primarily to create space for the vertical movement of the joint element. It is self-evident the blocks 52, 53 also forward the mechanical, thermal, and electrical functions of the springs 50, 51.

[0202] The torsion springs 50, 51 are made of a material with a coefficient of thermal conduction of at least 50 W/(mK), in particular at least 100 W/(mK), in particular at least 140 W/(mK).

[0203] The torsion springs 50, 51 may be made of silicon or a silicon compound. The joint 32 is preferably produced from highly doped monocrystalline silicon. This opens up a process compatibility of the production process with established MEMS manufacturing processes. Moreover, this leads to an advantageously high thermal conductivity and a good electric conductivity.

[0204] In the case of an absorbed power density of 10 kW/(m.sup.2) and mirror dimensions of 600 μm×600 μm, a temperature difference of 11 K emerges between the mirror body 27 and the substrate 39 with the specified values of the dimensions, in particular with a thickness of the torsion springs 50, 51 of 4 μm, and the thermal conductivity of the torsion springs 50, 51.

[0205] The torsion springs 50, 51 may also have a lower thickness. Should the torsion springs 50, 51 have a thickness of 2.4 μm, a temperature difference of 37 K emerges between the mirror body 27 and the substrate 39—in the case of otherwise identical parameter values.

[0206] In particular, the thermal conductivity of the torsion spring lies in the range of 0.5 K/kW/m.sup.2 to 10 K/kW/m.sup.2, with the thermal power density relating to the mean thermal power absorbed by the mirror. What could be achieved by such torsion springs is that the temperature difference between the mirror body 27 and the substrate 39 is less than 50 K, in particular less than 40 K, in particular less than 30 K, in particular less than 20 K.

[0207] In the variant of the joint 32 that is illustrated in FIG. 10, two pairs of bending springs 69, 70 are provided in place of the torsion springs 50, 51. The joint 32 also has a great stiffness in the horizontal degrees of freedom in this alternative. In this respect, reference is made to the description of the alternative illustrated in FIG. 9. The design aspects in view of the horizontal stiffness and in view of the mode separation of the parasitic eigenmodes likewise correspond to what was described above.

[0208] The variant of the joint 32 illustrated in FIG. 10 is a Cardan-type flexure with orthogonally arranged, horizontal bending springs 69, 70 that are embodied as leaf springs. Respectively two of the bending springs 69, 70 are connected to one another via a plate-shaped structure 67, which is also referred to as an intermediate plate.

[0209] Horizontal leaf springs are advantageous from a process point of view. In particular, they simplify the production of the joint 32.

[0210] In the variant in accordance with FIG. 10, the connecting blocks 52, 53 each have an elongate, rod-shaped embodiment. They extend substantially over the entire extent of the joint 32 in the direction of the tilt axes 33, 34.

[0211] A separation slot 68 is provided in each case between two of the connecting blocks 52, 53. Hence, the joint 32 has a two-part embodiment.

[0212] The joint 32 preferably has axial symmetry in relation to the surface normal 36. Hence, it has a two-fold rotational symmetry. The bending springs 69 and 70, in particular, each have a mirror symmetric embodiment in relation to the surface normal 36.

[0213] In the variant in accordance with FIG. 10, the stiffening element 55 is embodied in the form of two plate-shaped structures 67. In particular, the plate-shaped structures 67 are arranged parallel to the plane that is defined by the pivot axes 33, 34. The plate-shaped structures 67 connect the pivot axes 33, 34 that are realized by the bending springs 69, 70. In particular, the pivot axes 33, 34 are aligned orthogonal to one another.

[0214] In this alternative, the joint 32 includes a cutout 66 in a central region. The cutout 66 allows the arrangement of further components, for example a counterweight, on the mirror body 27 in the central region of the individual mirror 20, in particular in the region of the surface normal 36, without this leading to a collision with the joint 32. A corresponding cutout 66 can also be provided in the variant in accordance with FIG. 9.

[0215] The two plate-shaped structures 67 can also be connected to one another in the central region. As a result of this, an even higher stiffness of the joint 32 can be obtained in the vertical direction, i.e. in the direction of the surface normal 36.

[0216] Further aspects, in particular thermal aspects, of the optical component 30 are described below.

[0217] The transmitter electrodes 47 and the receiver electrodes 48 have a thermal contact with the substrate 39. The substrate 39 serves as a heatsink. Consequently, both the transmitter electrodes 47 and the receiver electrodes 48 are at the same temperature, or at least substantially at the same temperature, as the substrate 39. The active actuator transducer stator electrodes 37.sub.i also have a thermal contact with the substrate 39. They also preferably have substantially the same temperature as the substrate 39 during the operation of the displacement device 31. Consequently, the temperature of the sensor transducer stator electrodes 44.sub.i is substantially constant during the operation of the optical component 30. In particular, it is independent of the temperature of the individual mirror 20. Potential variations in the temperature of the substrate 39 can be compensated. In particular, they can be compensated substantially more easily than temperature variations of the individual mirror 20.

[0218] The optical component 30, which lies in the region of the surface normal 36, has a thermal center 59. A heat flow extends to the outside, substantially in the radial direction.

[0219] The sensor transducer stator electrodes 44.sub.i are arranged radially symmetrically relative to the thermal center 59. A thermal expansion of the individual mirror 20 only leads to a radial displacement of the comb fingers 46. By contrast, the sensor device is substantially insensitive.

[0220] Below, further aspects, embodiments and arrangements of the actuator transducer stator electrodes 37.sub.i and of the sensor transducer stator electrodes 44.sub.i are described with reference to FIG. 11.

[0221] In each case, two actuator transducer stator electrodes 37.sub.i that lie opposite one another in relation to the effective pivot point 35 form an electrode pair 60.sub.1, 60.sub.2. The electrode pairs 60.sub.1, 60.sub.2 are actuated in a differential manner. The electrode pairs 60.sub.i, 60.sub.2 can be actuated in a differential manner over the entire movement range of the individual mirror 20. As an alternative thereto, it is, in principle, also possible to have superposition at the center. They serve to tilt the individual mirror 20 about the actuator axes 61.sub.1 61.sub.2; the actuator axes 61.sub.1, 61.sub.2 extend along the diagonal of the optical component 30, in particular parallel to the diagonals of the mirror body 27 of the individual mirror 20. The actuator axes 61.sub.1, 61.sub.2 are defined by the actuator transducer electrodes 37.sub.i, 42 that are arranged in the quadrants 54.sub.1 and 54.sub.3, and 54.sub.2 and 54.sub.4, respectively. The actuator axes 61.sub.1, 61.sub.2 are respectively arranged twisted by 45° in relation to the tilt axes 33, 34 that are defined by the joint 32.

[0222] The sensor transducer stator electrodes 44.sub.i are arranged along the diagonal of the substrate 39. In each case, two sensor transducer stator electrodes 44.sub.i that lie opposite one another in relation to the effective pivot point 35 form an electrode pair 62.sub.1, 62.sub.2. The sensor transducer stator electrodes 44.sub.i of the electrode pairs 62.sub.1, 62.sub.2 are interconnected in a differential manner. They serve to determine the tilt or pivot position relative to the actuator axes 61.sub.1, 61.sub.2. Respectively one of the electrode pairs 62.sub.1, 62.sub.2 of the sensor device is assigned to one of the electrode pairs 60.sub.1, 60.sub.2 of the actuator transducer stator electrodes 37.sub.i and accordingly aligned like the latter.

[0223] All transducer electrodes 37.sub.i, 42.sub.i, 44.sub.i, 45 are embodied as comb electrodes with a plurality of comb fingers, wherein the respectively complementary comb fingers of mirror and stator engage in one another and therefore form a capacitor, the capacitance of which depends largely linearly on the immersion depth.

[0224] All comb fingers of the displacement device 31, in particular all comb fingers of the actuator transducer stator electrodes 37.sub.i, of the actuator mirror electrode 42, and of the sensor transducer stator electrodes 44.sub.i and of the sensor transducer mirror electrode 45 have the same dimensions in the direction of the surface normal 36. Inter alia, this simplifies the production of same. In particular, it is possible to produce the entire electrode structure which is arranged on the substrate 39 and/or the entire electrode structure which is connected to the mirror body 27 using one and the same sequence of process steps.

[0225] All active actuator transducer stator electrodes 37.sub.i have a thermal contact with the substrate 39. Consequently, their temperature during the operation of the displacement device 31 substantially corresponds to the temperature of the substrate 39. This leads to improved, substantially constant operating conditions.

[0226] The mirror body 27 is electrically grounded. An electrically conductive contact to this end is established by the joint 32. Alternatively, a defined bias voltage can be applied to the mirror body 27 by way of the joint 32 in order to set a different operating voltage operating point or region for actuators and sensors.

[0227] An emergence circle 63 has been plotted in FIG. 11 for elucidation purposes. The emergence circle 63 surrounds the region within which there is no emergence of the actuator mirror electrode 42 from the actuator transducer stator electrodes 37.sub.i or emergence of the comb fingers 46 from the sensor transducer stator electrodes 44.sub.i, even in the case of a maximum tilt of the individual mirror 20. The actuator mirror electrode 42 may emerge from the actuator transducer stator electrodes 37.sub.i outside of the emergence circle 63.

[0228] Preferably, all comb fingers 46 of the sensor device are arranged within the emergence circle 63. Consequently, the comb fingers 46 do not emerge from the sensor transducer stator electrodes 44.sub.i in any possible tilt position of the individual mirror 20. In particular, they never emerge completely from the sensor transducer stator electrodes 44.sub.i. This ensures that the tilt position of the individual mirror 20 can always be ascertained reliably with the aid of the sensor device.

[0229] Preferably, the emergence circle 63 has a diameter which substantially corresponds to the side length of the reflection surface 26 of the individual mirror 20. It may also be slightly larger. Provided that the emergence circle 63 has a diameter which, to all intents and purposes, corresponds to the diagonal of the reflection surface 26 of the individual mirror 20, an emergence of the actuator mirror electrode 42 from the actuator transducer stator electrodes 37.sub.i is completely avoided. This may be advantageous, but is not mandatory.

[0230] The radius of the emergence circle 63 depends on the maximum tilt angle range and on the comb overlap of the comb fingers.

[0231] The maximum possible tilt position of the individual mirror 20 can be restricted by mechanical elements, in particular by abutment elements. Such abutment elements may be arranged on the substrate 39. They are preferably arranged at the edge, i.e. outside the electrode structure of the displacement device 31.

[0232] A further variant of the optical component 30 is described below with reference to FIG. 12. The optical component 30 in accordance with the variant schematically illustrated in FIG. 12 corresponds to one of the variants described above, to which reference is made herewith.

[0233] In accordance with the variant that is schematically illustrated in FIG. 12, provision is made for arranging a compensation weight 64 on the side of the mirror body 27 that lies opposite the joint 32 in the direction of the surface normal 36. The compensation weight 64 is securely connected to the mirror body 27. In particular, it has a direct connection to the mirror body 27.

[0234] The compensation weight 64 is embodied and arranged in such a way that the mass centroid 65 of the mechanical system, which includes all constituent parts of the optical component 30 that move together with the mirror body 27 of the individual mirror 20, coincides, to all intents and purposes, with the effective pivot point 35. The mass centroid 65 can be displaced in a targeted manner by a targeted embodiment and arrangement of the compensation weight 64. By displacing the mass centroid 65 in such a way that the position thereof coincides with that of the effective pivot point 35, it is possible to substantially reduce the sensitivity of the individual mirror in relation to external disturbances. Moreover, parasitic eigenmodes are kept in a high-frequency range, which is sufficiently far away from the frequency spectrum that occurs during a displacement of the individual mirror 20 via the actuator device.

[0235] What can be achieved via the compensation weight 64 is that the mass centroid 65 of the mechanical system, which, as a matter of principle, may have been shifted out of the effective pivot point 35 of the joint 32, is pushed back into the effective pivot point 35.

[0236] In the direction of the surface normal 36, the compensation weight 64 may have a length of up to 500 μm.

[0237] Preferably, the compensation weight 64 has a rotational symmetry in relation to the surface normal 36. It can have in particular a cylindrical, in particular circular-cylindrical embodiment. Apart from a connecting piece, by which it is mechanically connected to the mirror body 27, it may also have a substantially spherical embodiment.

[0238] In particular, the compensation weight 64 has a rotational symmetry that corresponds to the rotational symmetry of the joint 32.

[0239] The compensation weight 64 may have circular-sector-shaped recesses. Moreover, it may have a central cavity that extends in the direction of the surface normal 36. This cavity facilitates access to the material under the joint 32. If desired, this material can be removed as sacrificial material.

[0240] What arranging the compensation weight 64, in particular by way of displacing the mass centroid 65 of the mechanical system in such a way that it coincides with the effective pivot point 35, achieves is that accelerations in the horizontal direction, which may e.g. be caused by mechanical vibrations, are not translated into tilt moments which have an interfering effect on the set mirror position. As a result of the compensation weight 64, the individual mirror 20 can be made less sensitive in relation to vibration excitations. In particular, the tilt angle stability at a given vibration spectrum is improved. Expressed differently, the arrangement of the compensation weight 64 forms a measure for reducing the mirror sensitivity in relation to disturbances.

[0241] In a particularly advantageous variant, the compensation weight 64 can simultaneously form an abutment element, in particular a so-called end stop, by which a maximum possible tilt of the individual mirror 20 is delimited. As a result of this, the individual mirror 20 can be protected from mechanical damage and/or an electrical short circuit. By em-bodying the compensation weight 64 as an abutment element, it can simultaneously be used as a mechanical reference for the mirror tilt. In particular, it is possible to examine and/or recalibrate the sensor device in relation to a possible drift via an end abutment gate. This renders it possible to dispense with an external measurement system. This substantially simplifies monitoring and/or calibrating of the sensor device.

[0242] On the other hand, the compensation weight 64 is embodied and arranged in such a way that it is without contact with the substrate 39 and the constituent parts of the displacement device 31 within the possible displacement range of the individual mirror 20. A specific recess in the substrate 39 may be provided for the compensation weight 64. In particular, the recess for the compensation weight 64 is arranged in the interior of the ring-shaped electrode structure.

[0243] The different variants of the displacement device 31, of the sensor device, of the joint 32 and of the remaining constituent parts of the optical component 30 can be combined substantially freely with one another.

[0244] In accordance with a further variant, the actuators may also be used as sensors at the same time. To this end, provision is made for reading the tilt-angle-dependent actuator capacity at a frequency that is significantly higher, in particular at least one decade higher, than the actuation frequency (control bandwidth). A separate sensor device can be dispensed with in this case. It is also possible to additionally provide a dedicated separate sensor device, in particular in accordance with the preceding description.

[0245] The displacement device 31 is preferably producible via a MEMS method. In particular, it has a design which is designed for a manufacture using MEMS method steps. In particular, it predominantly has, in particular exclusively has, horizontal layers which may be structured in the vertical direction.

[0246] In particular, the electrodes 37.sub.i, 42, 44.sub.i, 45 are producible via MEMS method steps. The joint 32 is preferably also producible via MEMS method steps.