MICROMECHANICAL COMPONENT AND MANUFACTURING METHOD FOR A MICROMECHANICAL COMPONENT

A micromechanical component including a mount, an adjustable part, and a meander-shaped spring. An outer end of the meander-shaped spring is attached to the mount and an inner end of the meander-shaped spring is attached to the adjustable part. An actuator device is formed at an outer surface of and/or in the meander-shaped spring in such a way that, using the actuator device, periodic deformations of the meander-shaped spring are excitable, by which the adjustable part is adjustable in relation to the mount around a rotational axis. The component includes a torsion spring which is situated on a side opposite to the meander-shaped spring and extends along the rotational axis and is attached at an outer end of the torsion spring to the mount and at an inner end of the torsion spring to the adjustable part. The meander-shaped spring is situated in sections on the rotational axis.

CROSS REFERENCE

The present application claims the benefit under 35 U.S.C. § 119 of German Patent Application No. DE 102019218468.5 filed on Nov. 28, 2019, which is expressly incorporated herein by reference in its entirety.

FIELD

The present invention relates to a micromechanical component. The present invention also relates to a manufacturing method for a micromechanical component.

BACKGROUND INFORMATION

An adjustable micromirror is described in Japan Patent Application No. JP 2009-223165 A, which is to be adjustable with the aid of two meander-shaped springs having sections that are each covered by at least one piezoelectric material, in relation to a mount of the adjustable micromirror. In particular, alternately a bending stress or a tensile stress is to be able to be formed on the sections of the two meander-shaped springs by applying at least one voltage to the at least one piezoelectric material in such a way that the adjustable micromirror is adjusted in relation to its mount with the aid of an effectuated mirror-symmetrical deformation of the two meander-shaped springs.

An object of the present invention is to provide a simplified micromechanical component.

SUMMARY

In accordance with an example embodiment of the present invention, a micromechanical component including a mount, an adjustable part, and a meander-shaped spring is provided. The meander-shaped spring is attached in this case at an outer end of the meander-shaped spring directly or indirectly to the mount and at an inner end of the meander-shaped spring directly or indirectly to the adjustable part. An actuator device is formed on an outer surface of the meander-shaped spring and/or in the meander-shaped spring in such a way that periodic deformations of the meander-shaped spring are excitable with the aid of the actuator device, by which the adjustable part is adjustable in relation to the mount around a rotational axis of the adjustable part. In addition, the mechanical component includes a torsion spring. This torsion spring is situated on a side opposite to the meander-shaped spring with respect to a plane which is situated perpendicularly to the rotational axis of the adjustable part. The rotational axis is thus essentially orthogonal to this plane. This plane corresponds in particular to a plane of symmetry of the adjustable part, in particular a micromirror. The torsion spring extends at least in sections along the rotational axis and is attached at an outer end of the torsion spring directly or indirectly to the mount and at an inner end of the torsion spring directly or indirectly to the adjustable part. The meander-shaped spring which is located on the other side of the plane is situated in sections on the rotational axis.

The drive of the adjustable part is thus provided by only one single meandering drive. A passive torsion spring, which is used for suspending the adjustable part at the mount, is situated opposite to the meandering drive. The deflection of the adjustable part may be determined easily by this torsion spring, since in a torsion spring without drive, the deflection angle is proportional to the load measured at the torsion spring. A further advantage of this mechanical component is that the torsion spring requires less space than a second meandering drive. Space may thus be saved.

The meander-shaped spring preferably extends in sections along the rotational axis. A relatively symmetrical suspension of the adjustable part at the mount thus results.

An extension of the meander-shaped spring in the direction of an axis essentially perpendicular to the rotational axis preferably corresponds to at least 50% of an extension of the adjustable part in the direction of the axis essentially perpendicular to the rotational axis. The axis essentially perpendicular to the rotational axis is in particular a transverse axis of the adjustable part, in particular a micromirror. Since the micromechanical component only has one single meandering drive on one side of the adjustable part, this meandering drive may be designed to be wider and a greater deflection angle of the adjustable part may thus be achieved upon deflection. The extension of the meander-shaped spring in the direction of the axis essentially perpendicular to the rotational axis preferably corresponds to the extension of the adjustable part in the direction of the axis essentially perpendicular to the rotational axis. The meandering drive thus uses the full width of the micromirror. The greatest possible deflection angle of the adjustable part may thus be achieved by only one single meandering drive.

The meander-shaped spring is preferably attached centrally in the rotational axis of the adjustable part directly or indirectly at the adjustable part. A symmetrical suspension of the adjustable part at the mount thus results.

The adjustable part is preferably designed as a micromirror. The mirror surface of the micromirror is in particular formed rectangular or circular here. The micromirror or its mirror surface thus has two planes of symmetry situated perpendicularly to one another.

The torsion spring preferably has a height and a width, the height of the torsion spring being designed to be greater than the width of the torsion spring. In particular, a dimension of the height in relation to a dimension of the width of the torsion spring corresponds at least to a ratio of 1.2:1. A comparatively tall and narrow torsion spring thus results, which is designed to be comparatively soft with respect to the torsion deformation. The meandering drive thus does not have to exert a large force to deflect the torsion spring. A large deflection angle of the adjustable part may thus in turn be maintained. However, a torsion spring designed in this way is designed to be comparatively rigid in the z direction. The z mode, also called the stroke mode, is shifted toward higher frequencies by this torsion spring which is rigid in the z direction, which is accompanied by advantages for the control of the adjustable part, in particular the micromirror.

The torsion spring is preferably designed as a meandering torsion spring. This saves space in relation to a linear torsion spring and the micromechanical component may thus be designed to be smaller as a whole.

The micromechanical component preferably includes at least one sensor device, which is designed to output or provide at least one sensor signal corresponding to a deflection of the adjustable part from its idle position in relation to the mount. The sensor device is connected via at least one signal line formed on an outer surface of the torsion spring and/or in the torsion spring to evaluation electronics formed on the mount or an evaluation electronics connection contact formed on the outer surface of the mount. For electrical contacting of the sensor device, a signal line formed on the outer surface and/or in the at least two meander-shaped springs according to the related art may thus be omitted. The electrical contacting of the sensor device is thus not linked to any secondary effects with regard to a desired good flexibility of the meander-shaped springs. Alternatively, the sensor device is preferably situated at the outer end of the torsion spring and is connected via at least one signal line formed on an outer surface of the mount and/or in the mount to evaluation electronics formed on the mount or an evaluation electronics connection contact formed on the outer surface of the mount. Leading the signal line via the torsion spring may thus also be omitted.

The actuator device preferably includes at least one piezoelectric actuator layer made of at least one piezoelectric material, which is formed on the outer surface and/or in multiple sections of the associated meander-shaped spring. The actuator device additionally includes at least one electrical line, which is formed on the outer surface and/or in the meander-shaped spring in such a way that at least one voltage signal is applicable to the piezoelectric actuator layer of the meander-shaped spring in such a way that the periodic deformations of the meander-shaped spring may be effectuated. In this way, the sections of the meander-shaped spring formed having the piezoelectric actuator layer may be bent so that the adjustable part is adjusted by a relatively high adjustment angle out of its idle position in relation to the mount around the rotational axis.

The above-described advantages are also provided when a corresponding manufacturing method is carried out for such a micromechanical component. It is to be expressly noted that the manufacturing method may be refined in such a way that all above-explained micromechanical components may be manufactured thereby.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS

FIG. 1ashows a schematic overall representation of a first specific embodiment of micromechanical component1a. Micromechanical component1aincludes a mount10a, an adjustable part2a, and a meander-shaped spring3a. Meander-shaped spring3ais attached here at an outer end23aof meander-shaped spring3adirectly to mount10aand at an inner end23bof meander-shaped spring3adirectly to adjustable part2a. In this first exemplary embodiment, meander-shaped spring3ais attached at inner end23bof meander-shaped spring3acentrally in rotational axis30bof adjustable part2adirectly to adjustable part2a. An actuator device20aand20bin the form of a piezoelectric layer is formed in meander-shaped spring3ain such a way that periodic deformations of meander-shaped spring3aare excitable with the aid of actuator device20aand20b, by which adjustable part2ais adjustable in relation to mount10aaround a rotational axis30bof adjustable part2a. In addition, mechanical component1aincludes a torsion spring6a. This torsion spring6ais formed here as a linear torsion spring. The torsion spring is situated on a side opposite to meander-shaped spring3awith respect to a plane9a, which is situated essentially perpendicularly to rotational axis30bof adjustable part2a. Rotational axis30bis thus essentially orthogonal to this plane. Adjustable part2ais designed here by way of example as a micromirror having a rectangular mirror surface. Adjustable part2athus has two planes of symmetry situated perpendicularly to one another in this specific embodiment. Plane9asituated perpendicularly to rotational axis30bof adjustable part2acorresponds in this context to a first plane of symmetry of adjustable part2a. Rotational axis30bextends in the direction of second plane of symmetry8aof adjustable part2a.

Torsion spring6aextends in this exemplary embodiment in section7acompletely along rotational axis30band is attached at an outer end26bdirectly to mount10a. At an inner end of torsion spring6a, torsion spring6ais directly attached to adjustable part2a. On the one hand, torsion spring6acontributes to stabilizing the desired rotational movement of adjustable part2aaround rotational axis30b. In particular, torsion spring6aincreases a rigidity of micromechanical component1ain relation to an undesired adjustment movement of adjustable part2ain an axis30aaligned perpendicularly to rotational axis30b. On the other hand, the deflection of the adjustable part may also be determined easily via torsion spring6a, since in a torsion spring without drive, the deflection angle is proportional to the load measured at the torsion spring.

In contrast, meander-shaped spring3a, which is located on the other side of plane9a, is only situated in sections4a,23a, and23bon rotational axis30b. While meander-shaped spring3aonly intersects rotational axis30bin sections4a, meander-shaped spring3aextends in sections23aand23balong rotational axis30b.

Due to the meandering shape, meander-shaped spring3amay be made comparatively long without the individual length of meander-shaped spring3acontributing to a significant enlargement of micromechanical component1a. An individual length of meander-shaped spring3amay be, for example, greater than or equal to 200 μm, in particular greater than or equal to 500 μm, especially greater than or equal to 1 mm (millimeter).

In the example ofFIG. 1, actuator device20aand20bincludes in each case at least one piezoelectric actuator layer (not shown here) made of at least one piezoelectric material. The piezoelectric material may be, for example, PZT. The piezoelectric actuator layer may have, for example, a layer thickness between 0.5 μm (micrometer) and 2 μm (micrometer). For the interaction with the piezoelectric actuator layer, actuator device20aand20balso has at least one electrical line (not shown), which is formed at an outer surface and/or in meander-shaped spring3a. Therefore, at least one voltage signal may be applied to the piezoelectric actuator layer in such a way that at least the periodic deformations of meander-shaped spring3amay be effectuated/are effectuated. Such a design of actuator device20aand20bas a piezoelectric actuator device is distinguished by high adjustment forces, but only low positioning distances. An adjustment of adjustable part2aaround rotational axis30bwith the aid of piezoelectric actuator devices20aand20bdescribed here preferably does not take place in a resonant manner. If voltage is not applied to the piezoelectric actuator layer, adjustable part2ais thus provided in its so-called idle position in relation to mount10a.

As an advantageous refinement of the present invention, the micromechanical component may also include at least one sensor device15a, which is designed to output or provide at least one sensor signal corresponding to a deflection of adjustable part2aout of its idle position in relation to mount10a. Sensor device15amay be, for example, a piezoelectric or piezoresistive sensor device15a. In this exemplary embodiment, sensor device15ais formed on an “anchoring area” of torsion spring6aat mount10a. The formation of sensor device15aat the outer end of torsion spring6aenables an unambiguous detection/recognition of a deflection of adjustable part2aout of its idle position around rotational axis30bin relation to mount10a. In particular, such a design of sensor device15ais more advantageous than the conventional positioning of a sensor at one of meander-shaped springs3a, which often does not permit reliable correlation to the deflection of adjustable part2aand furthermore results in the disadvantage that interference modes of micromechanical component1aare incorrectly indicated as the desired deflection of adjustable part2aout of its idle position around rotational axis30b.

Sensor device15ais advantageously additionally connected via at least one signal line (not shown) formed at the outer surface of mount10ato evaluation electronics formed on mount10aor an evaluation electronics connection contact formed on mount10a. Forming the at least one signal line at the outer surface and/or in meander-shaped spring3amay thus be omitted without problems. A bending rigidity of meander-shaped spring3ais thus not negatively affected by the signal line guided via torsion spring6a. Furthermore, the signal line is not influenced by the convex/concave bending of meander-shaped spring3anor do the electrical signals interfere with the actuator and sensor signal line.

In this first specific embodiment of the present invention, meander-shaped spring3ahas an extension14ain the direction of an axis30aessentially perpendicular to rotational axis30b, which is at least 50% of an extension12aof adjustable part2ain the direction of axis30aessentially perpendicular to rotational axis30b. The extension of meander-shaped spring3ais in this case a length of the bent spring sections in the corresponding direction. The extension of adjustable part2ais in this context a width of adjustable part2a.

Torsion spring6ahas in this case a height (not shown in this illustration) and a width17a. The height of the torsion spring is greater than width17aof torsion spring6a.

FIG. 1bshows a schematic overall illustration of a second specific embodiment of micromechanical component1b, in accordance with the present invention.

In this case, in contrast to the first specific embodiment, extension14bof meander-shaped spring3bin the direction of axis30aessentially perpendicular to rotational axis30bcorresponds to extension12aof adjustable part2ain the direction of axis30aessentially perpendicular to rotational axis30b. The maximum deflection angle of adjustable part2ais thus achieved.

FIG. 1cshows a schematic overall illustration of a third specific embodiment of micromechanical component1c, in accordance with the present invention.

In contrast to the second specific embodiment, torsion spring6cis formed as a meandering torsion spring in this case. Meandering torsion spring6cextends on sections7con rotational axis30band is attached at an outer end26dof torsion spring6cdirectly to mount2aand at an inner end26cof torsion spring6cdirectly to adjustable part2a.

FIG. 2shows a flowchart to explain one specific embodiment of the manufacturing method, in accordance with the present invention.

All above-described micromechanical components may be manufactured with the aid of the manufacturing method described hereinafter. However, a feasibility of the manufacturing method is not restricted to the manufacturing of the above-described micromechanical components.

Attaching an adjustable part to a mount via at least one meander-shaped spring, which is situated sectionally on a rotational axis of the adjustable part, an outer end of the meander-shaped spring being attached directly or indirectly to the mount and an inner end of the meander-shaped spring being attached directly or indirectly to the adjustable part; and forming an actuator device at an outer surface of the meander-shaped spring and/or in the meander-shaped spring in such a way that during operation of the later micromechanical component with the aid of the actuator device, periodic deformations of the meander-shaped spring are excited, by which the adjustable part is adjusted in relation to the mount around the rotational axis of the adjustable part;

characterized by the step:

forming a torsion spring, which extends at least sectionally along the rotational axis of the adjustable part, where an outer end of the torsion spring is attached directly or indirectly to the mount and an inner end of the torsion spring is attached directly or indirectly to the adjustable part in such a way that the adjustable part is adjusted with the aid of at least the periodic deformations of the meander-shaped spring in relation to the mount around the rotational axis.

In a method step50, an adjustable part is attached to a mount via at least one meander-shaped spring. The meander-shaped spring is situated for this purpose in sections on a rotational axis of the adjustable part. An outer end of the meander-shaped spring is attached directly or indirectly to the mount and an inner end of the meander-shaped spring is attached directly or indirectly to the adjustable part. In a following method step51, an actuator device is formed at an outer surface of the meander-shaped spring and/or in the meander-shaped spring in such a way that during operation of the later micromechanical component with the aid of the actuator device, periodic deformations of the meander-shaped spring are excited. The adjustable part is adjusted in relation to the mount by these excited periodic deformations.

In a following method step52, a torsion spring is formed, which extends at least in sections along the rotational axis of the adjustable part. An outer end of the torsion spring is attached directly or indirectly to the mount and an inner end of the torsion spring is attached directly or indirectly to the adjustable part. This has the effect that the adjustable part is adjusted with the aid of at least the periodic deformations of the meander-shaped spring in relation to the mount around the rotational axis. The manufacturing method described here thus also effectuates the above-described advantages. To carry out method steps50and52, the particular components may be structured, for example, out of monocrystalline, polycrystalline, or epi-polycrystalline silicon, especially out of a silicon layer of an SOI substrate (silicon-on-insulator substrate).

As an optional refinement, the manufacturing method may also include method steps53and54. In method step53, a sensor device is formed for providing or outputting at least one sensor signal corresponding to a deflection of the adjustable part out of its idle position in relation to the mount. In method step54, the sensor device is connected via at least one signal line formed at an outer surface of the torsion spring and/or in the torsion spring to evaluation electronics formed on the mount or an evaluation electronics connection contact formed on the mount. Alternatively to this step, the sensor device is connected via at least one signal line formed on an outer surface of the mount and/or in the mount to evaluation electronics formed at the mount or an evaluation electronics connection contact formed on the mount. Further components of the above-described micromechanical components may also be formed with the aid of corresponding method steps. The above-described micromechanical components are technologically implementable in a simple manner.

Method steps50through54may be carried out in any sequence, overlapping in time, or simultaneously.