Piezoelectric mirror component, method for operating the piezoelectric mirror component, and projection apparatus having the piezoelectric mirror component

Abstract

A piezoelectric mirror component (100) is presented, and the piezoelectric mirror component is - Mirror element (10), - A piezoelectric drive ring (20) surrounding the mirror element (10) and connected to the mirror element (10) through one or more first torsion spring elements (41), and - Includes a frame element (30) connected to the drive ring (20) through one or more second torsion spring elements (42), and The above one or more second torsion spring elements (42) extend from the drive ring (20) to the frame element (30).

Description

Technology Field

[0001] A piezoelectric mirror component, a method of operating the piezoelectric mirror component, and a projection device equipped with the piezoelectric mirror component are presented. Background Technology

[0002] Laser projectors have a wide range of applications. For example, projectors are used to display moving images in movie theaters, home cinema applications, or mobile display applications. Ideally, for these uses, cost-effective projectors that are not sensitive to vibration should be used. Additionally, projectors are increasingly being used in the automotive sector, for instance, to project information onto the road surface or in applications based on LIDAR principles, such as matrix lighting. These applications require the large depth of field that laser projectors can provide. Furthermore, laser projectors are also advantageous for applications used in conjunction with VR ("virtual reality") and AR ("augmented reality"), such as with AR / VR glasses.

[0003] Projectors can be equipped with rotating mirrors that deflect a time-modulated laser beam. In this way, an image is generated in a distant area perceived by the observer, ensuring that the projected image is always in focus for the observer and eliminating the need for eye adjustment. For example, in the case of AR / VR glasses, the deflected beam is coupled to a waveguide lens. Here, the observer's image point location is determined by the direction rather than the position of the beam, so additional optics are not required. Often, two mirrors are used, one for each orthogonal deflection direction, as the laser beam scans the image area on an orthogonal grid. Alternatively, there are solutions using laser arrays, LED arrays (LED: Light Emitting Diode), or QLED arrays (QLED: Quantum Dot Light Emitting Diode), but these offer limited resolution and brightness. There are also solutions where laser light is selectively reflected by passive panels, although energy efficiency is not particularly high. Consequently, there is high demand for compact solutions for AR / VR glasses that offer good image resolution.

[0004] For example, micromirrors are disclosed in the following documents: U. Baran et al., "Resonant PZT MEMS Scanner for High-Resolution Displays," Journal of Microelectromechanical Systems, 21, 1303-1310, 2012 describes a mirror capable of one-dimensional scanning by vibrating around a single axis. Ch. Pan et al., "A New Two-Axis Optical Scanner Actuated by Piezoelectric Bimorphs," International Journal of Optomechatronics, 6, 336-349, 2012 describes a rectangular mirror that moves two-dimensionally, where movement in one direction is non-harmonic motion in the so-called locking mode. JP 5345102 B2 and H.-J. Quenzer et al., "Piezoelectrically driven translatory optical MEMS actuator with 7mm apertures and large displacements," Proc. The document SPIE 9375, MOEMS and Miniaturized Systems XIV, 937500, 2015 describes a symmetrically suspended mirror movable around two axes, where the movements around both axes are similar and can lead to undesirable coupled motion. M. Tani et al., "A Combination of Fast Resonant Mode and Slow Static Deflection of SOI-PZT Actuators for MEMS Image Projection Display", Proc. IEEE / LEOS Int. Conf. Opt. MEMS Appl. Conf.The document in , 25-26, 2006 also describes a mirror capable of moving around two axes, in which the actuator for one of the rotational movements is somewhat compact, allows only low resonant frequencies, and has a large curvature structure that can be sensitive to shock. The document in H. Yu et al., "Optimization of MOEMS Projection Module Performance with Enhanced Piezoresistive Sensitivity", Micromachines 2020, 11, 651 describes an electromagnetically driven mirror. The problem to be solved

[0005] One or more of the specific embodiments is to present a piezoelectric mirror component. One or more additional embodiments are to provide a method of operating the piezoelectric mirror component. One or more other embodiments are to present a projection device having the piezoelectric mirror component. means of solving the problem

[0006] These problems are solved by the objects and methods according to the independent patent claims. Preferred embodiments and further improvements of said objects and methods are described in the dependent claims and are further described in the following description and drawings.

[0007] According to one or more embodiments, a piezoelectric mirror component, hereinafter also referred to as a mirror component, comprises a mirror element, a piezoelectric drive ring, and a frame element. The drive ring surrounds the mirror element and is connected to the mirror element through one or more first torsion spring elements. The frame element is connected to the drive ring through one or more second torsion spring elements. The mirror element, the drive ring, the frame element, and the torsion spring elements may be aligned along a plane, particularly in the idle state of the mirror component.

[0008] A piezoelectric layer is provided in at least the drive ring, and this piezoelectric layer is disposed between the first electrode and the second electrode. The piezoelectric layer may have one or more piezoelectric materials. Particularly preferably, the piezoelectric layer comprises or is made through a piezoelectric material based on lead zirconate titanate (PZT).

[0009] At least the second electrode is preferably structured into a plurality of drive control regions. This means that the second electrode may have a plurality of regions that can be driven and controlled independently of each other. The first electrode and / or piezoelectric layer may be provided continuously or at least partially structured. Thus, preferably, the first electrode and the second electrode structured into a plurality of drive control regions are provided in the drive ring, in which case the piezoelectric layer is disposed between the first electrode and the second electrode. Particularly preferably, the first electrode, the piezoelectric layer, and the second electrode are provided in this order. By applying a voltage between one or more control regions of the first electrode and the second electrode, mechanical deformation of the piezoelectric layer and thus the drive ring can occur in a partial region through the inverse piezoelectric effect, thereby applying a force to the drive ring and / or mirror element. Thus, each drive region can form a piezoelectric element together with the piezoelectric layer and the first electrode, thereby allowing a partial region of the mirror component to move. When an alternating current signal with a vibrating voltage is applied, a vibrating force can be applied that can cause vibrating deformation. As a result, at least a part of the mirror component can be set to vibrate.

[0010] One or more first torsion spring elements and one or more second torsion spring elements may be formed, in particular, into a so-called torsion bar. That is, each torsion spring element is formed in the form of a beam having a longitudinal direction capable of performing torsional motion about an axis of rotation, particularly during the operation of the mirror component, and the axis of rotation preferably corresponds substantially to the longitudinal direction of the beam.

[0011] One or more first torsion spring elements preferably rotate from the mirror element to the drive ring and define a first rotation axis. When the mirror element and the drive ring rotate relative to each other about the first rotation axis, the end of one or more first torsion spring elements closer to the mirror element rotates relative to the end of one or more first torsion spring elements closer to the drive ring. In particular, if the drive control regions of the second electrode are appropriately driven by a first alternating current signal having a first frequency, the mirror element can be set to a first rotational vibration having the first frequency, in which case, preferably, a restoring force that depends linearly on the rotation angle is applied to the mirror element through one or more first torsion spring elements. Such rotational vibration for one or more torsion spring elements is also referred to as torsional vibration below. Therefore, the first rotational vibration may also be referred to as a first torsional vibration.

[0012] One or more second torsion spring elements are preferably rotated from the drive ring to the frame element, defining a second rotation axis. When the frame element and the drive ring rotate relative to each other around the second rotation axis, the end of one or more second torsion spring elements closer to the frame element rotates relative to the end of one or more second torsion spring elements closer to the drive ring. In particular, if the drive control regions of the second electrode are appropriately driven by a second alternating current signal having a second frequency, the drive ring can be set to a second rotational vibration having a second frequency, in which case, preferably, a restoring force that depends linearly on the rotation angle can be applied to the drive ring through one or more second torsion spring elements. In particular, the mirror element can perform the second rotational vibration together with the drive ring. The described second rotational vibration may also be referred to as a second torsional vibration.

[0013] Particularly preferably, the first torsion spring element and the second torsion spring element are arranged so as to be rotated 90° relative to each other such that the first axis of rotation for the first torsional vibration and the second axis of rotation for the second torsional vibration are perpendicular to each other. In this way, the first and second torsional vibrations can be achieved to be as independent of each other as possible.

[0014] According to additional embodiments, the first electrode is also provided at least partially to the frame element. Additionally, the piezoelectric layer may also be provided at least partially to the frame element. Additionally, the second electrode may also be provided at least partially to the frame element. Additionally, the first electrode and / or the piezoelectric layer may be provided to one or more second torsion spring elements. Additionally, one or more second torsion spring elements may not have the second electrode. Particularly preferably, one or more first torsion spring elements and mirror elements do not have the first electrode, the piezoelectric layer, and the second electrode.

[0015] According to an additional embodiment, the second electrode is structured on the frame element in a plurality of drive control regions. In particular, the second electrode may be provided in an operating region of the frame element surrounded by the edge portion of the frame element. Consequently, additional drive regions may be provided on the frame element in addition to the drive control regions of the drive ring, thereby allowing force to be applied to the drive ring, for example, during appropriate drive control.

[0016] Additionally, contact elements for driving and controlling the first and second electrodes may be provided on the frame element, for example, at the edge portion of the frame element. The drive ring and / or control regions of the frame element may be connected to the contact elements of the frame element via conductor tracks that rotate across one or more second torsion spring elements. Alternatively, the conductor tracks may be omitted and the electrodes may be directly bonded. This avoids parasitic resistance and capacitance that may occur in relation to the conductor tracks.

[0017] As described above, in the method of operating the piezoelectric mirror component, the mirror element is preferably set to a first torsional vibration by a first alternating current signal having a first frequency acting on a first drive control region. Preferably, together with the mirror element, the drive ring is set to a second torsional vibration by a second alternating current signal having a second frequency acting on a second drive control region. In particular, since drive control by the first alternating current signal and drive control by the second alternating current signal can be performed simultaneously, the mirror element can perform both torsional vibrations simultaneously; in this case, the mirror element vibrates relative to the drive ring around a first rotation axis at the first frequency, and the drive ring vibrates relative to the frame element around a second rotation axis at the second frequency together with the mirror element. The first frequency and the second frequency may be particularly resonant frequencies or at least close to each resonant frequency, which may vary depending on each vibrating part of the mirror component and its geometric configuration. Particularly preferably, the first frequency and the second frequency are different.

[0018] According to an additional embodiment, the projection device includes a laser light source and a piezoelectric mirror component. The mirror component can deflect laser light emitted by the laser light source during operation. As a result of the torsional vibration of the mirror element described above, the deflected laser light can pass over an image area perceivable by an observer. That is, scanning can be achieved by the mirror component. Particularly preferably, so-called Lissajous scanning can be achieved at resonance or near-resonance torsional vibrations with respect to a first rotation axis and a second rotation axis that are perpendicular to each other, as described above.

[0019] The aforementioned features and embodiments are equally related to a piezoelectric mirror component, a method of operating the piezoelectric mirror component, and a projection device equipped with the piezoelectric mirror component.

[0020] According to an additional embodiment, the drive ring has a first diameter along a first direction and a second diameter along a second direction perpendicular to the first direction, wherein the first diameter is different from the second diameter. Particularly preferably, the first diameter is larger than the second diameter. Thus, the drive ring does not have a circular shape. In particular, the drive ring may have an elliptical shape or at least a shape close to elliptical.

[0021] The drive ring may be bounded by an inner edge facing the mirror element and an outer edge facing in directions along a plane spanning the first and second directions, wherein the inner and outer edges may each have an elliptical shape or at least a shape close to elliptical. The shape of the outer edge may be defined by a first diameter and a second diameter. That is, the aforementioned first diameter and second diameter may be the first outer diameter and second outer diameter of the drive ring. The inner edge may also have a first and second diameter, which may also be referred to as a first inner diameter and a second inner diameter, wherein the first inner diameter is rotated along the first direction and the second inner diameter is rotated along the second direction. The ratio of the first outer diameter to the second outer diameter may be equal to or different from the ratio of the first inner diameter to the second inner diameter. If the ratio is different, this may specifically mean that the drive ring has a first width along the first direction and a second width along the second direction, and that the first width is different from the second width. For example, the first width may be smaller than the second width.

[0022] In particular, one or more first torsion spring elements may be arranged along a first direction, while one or more second torsion spring elements may be arranged along a second direction. Particularly preferably, the drive ring is connected to the mirror element through two first torsion spring elements arranged along a straight line in the first direction on two opposing sides of the mirror element. Additionally, the drive ring is particularly preferably connected to the frame element through two second torsion spring elements arranged along a straight line in the second direction on two opposing sides of the drive ring. Each first torsion spring element and each second torsion spring element may have the features described in each case with respect to one or more torsion spring elements and one or more second torsion spring elements. In particular, the mirror element may be connected exclusively to the drive ring by the first torsion spring elements, while the drive ring may be particularly preferably connected exclusively to the frame element through the second torsion spring elements.

[0023] According to an additional embodiment, the mirror element has a mirror area and a border area surrounding the mirror area, and the border area is preferably partially separated from the mirror area by one or more through holes. The mirror element may be particularly preferably circular, and thus one or more through holes may have an arc shape. Particularly preferably, there may be two through holes facing each other and both having an arc shape.

[0024] Additionally, the mirror region may be elliptical and may have a larger elliptical axis and a smaller elliptical axis. Preferably, the larger elliptical axis is oriented along a first direction and the smaller elliptical axis is oriented along a second direction. Alternatively, the larger elliptical axis may be oriented along a second direction and the smaller elliptical axis along a first direction. In the case of the elliptical mirror region, the through holes have the shape of an elliptical arc. The ratio of the larger elliptical axis to the smaller elliptical axis may preferably be greater than 1, or greater than or equal to 1.02, or greater than or equal to 1.04, or greater than or equal to 1.06, as well as less than or equal to 1.1, or less than or equal to 1.08, or less than or equal to 1.07.

[0025] The border area can be connected to the mirror area through two connecting areas. That is, the two through holes can be separated from each other by two connecting areas. Particularly preferably, the connecting areas are arranged along a second direction on two opposing sides of the mirror area, so that the two through holes can be positioned facing each other along a first direction.

[0026] According to an additional embodiment, a reflective coating is provided on the mirror area. For example, the coating may be a metal coating. Additionally, a dielectric coating, such as a Bragg mirror, is also possible. The edge area and the connection area preferably do not have a reflective coating.

[0027] According to an additional embodiment, a frame element surrounds a drive ring. The frame element may, in particular, have a recess penetrating the frame element, in which one or more second torsion spring elements and one or more first torsion spring elements and mirror elements are disposed in the drive ring may be disposed. One or more second torsion spring elements are particularly preferably protruded from the edge surface surrounding the recess and protruded from the frame element into the recess. The recess preferably has a basic polygonal shape, which may be, for example, a square, a hexagon, or an octagon. Additionally, the recess may have identical extensions along the first and second directions. If the frame element has an operating area, this operating area may be directly adjacent to the recess. Additionally, the operating area may be partially separated from the edge portion by one or more through holes.

[0028] According to additional embodiments, the mirror element and the drive ring have a thickness smaller than one or more frame portions of the frame element. Herein and below, "thickness" may mean rotational axis along a third direction particularly perpendicular to the first and second directions. If the frame element has an operating area, preferably the operating area may also have a thickness smaller than the frame portions of the frame element.

[0029] Particularly preferably, the frame element, drive ring, mirror element, and torsion spring element are formed integrally. In particular, the frame element, drive ring, mirror element, and torsion spring element may have silicon. To manufacture the mirror component, a carrier in the form of a silicon wafer or an SOI wafer (SOI: "silicon on insulator") may be provided, and this carrier is structured to form, for example, the frame element, drive ring, mirror element, and torsion spring element. Then, electrodes and a piezoelectric layer, and, depending on the design, insulating layers and / or conductor tracks may be formed or provided on the structured carrier.

[0030] According to additional embodiments, measurements are provided to achieve positioning of a mirror element and / or positioning of a drive ring and / or frequency determination of torsional vibration of one or both. For example, during operation of a piezoelectric mirror element, a second frequency may be measured from a first AC signal and a first frequency may be measured from a second AC signal. This can be achieved, for example, by using appropriate frequency filters on the drive supply lines so that additional lines are not required. Additionally, it is possible to provide a third drive control area where a piezoelectric signal is measured through the piezoelectric effect. In particular, the third drive control areas may be provided at appropriate locations to obtain a good signal.

[0031] Additionally, at least two electrode elements may be provided for position and / or frequency measurement, and these electrode elements form a capacitor having variable capacitance when the mirror element is moved particularly relative to the drive ring or when the drive ring is moved particularly relative to the frame element, in which case the capacitance of said capacitor is measured. Through such capacitive measurement, zero crossings of the drive ring and / or mirror element may also be determined particularly. The first electrode may be appropriately structured to prevent capacitive short circuits.

[0032] Electrode elements can be formed, for example, by conductor track components. For example, a first electrode element can be placed on a frame element, while a second electrode element can be placed on a drive ring adjacent to the first electrode element. As the drive ring moves relative to the frame element, the distance between the electrode elements can change, and consequently, the capacitance of the capacitor formed by the electrode elements can change. Thus, for example, electrode elements can be placed on the drive ring and the mirror element. For example, it may be possible to place two electrode elements on the frame elements of the opposing sides of the drive ring so that the drive ring is positioned between the two electrode elements placed on the frame element. Then, the drive ring can act as a moving dielectric between the electrode elements during movement, and consequently, the capacitance of the formed capacitor can change. Thus, two electrode elements may also be placed on the opposing sides of the mirror element of the drive ring.

[0033] In addition, there may be first and / or second drive control regions that are alternately used in a time division multiplexing process to drive the mirror element or drive ring and measure the piezoelectric signal.

[0034] Additional advantages, preferred embodiments, and improvements are shown from the embodiments described below together with the drawings. Brief explanation of the drawing

[0035] FIGS. 1a and 1b are schematic drawings illustrating a piezoelectric mirror component according to an embodiment, and FIGS. 2a to 2e schematically illustrate process steps for manufacturing a piezoelectric mirror component according to FIGS. 1a and 1b, and FIGS. 3a and 3b are schematic diagrams illustrating the process steps of a process for operating a piezoelectric mirror component according to FIGS. 1a and 1b, and FIGS. 4a through 5e illustrate simulation tests for the piezoelectric mirror components shown in FIGS. 1a and 1b, and FIGS. 6a and 6b are schematic drawings illustrating a piezoelectric mirror component according to an additional embodiment, and FIGS. 7a to 7e schematically illustrate process steps for manufacturing a piezoelectric mirror component according to FIGS. 6a and 6b, and FIGS. 8a to 8e schematically illustrate process steps for operating a piezoelectric mirror component according to FIGS. 6a and 6b, and FIGS. 9a through 12e illustrate simulation tests for the piezoelectric mirror components shown in FIGS. 6a and 6b, and FIGS. 13a and 13b are schematic drawings illustrating a piezoelectric mirror component according to an additional embodiment, and FIGS. 14a to 14e schematically illustrate process steps for manufacturing a piezoelectric mirror component according to FIGS. 13a and 13b, and FIG. 15 is a schematic diagram illustrating the process steps of a process for operating a piezoelectric mirror component according to FIG. 13a and 13b, and FIGS. 16a through 16e illustrate simulation tests for the piezoelectric mirror components shown in FIGS. 13a and 13b, and FIG. 17 is a schematic drawing illustrating a projection device according to an additional embodiment, and FIGS. 18a through 18e schematically illustrate a measurement method for determining the position and / or frequency of a component of a piezoelectric mirror component according to some embodiments, and FIGS. 19a and 19b are schematic drawings illustrating parts of a piezoelectric mirror component according to additional embodiments. Specific details for implementing the invention

[0036] In the embodiments and drawings, elements of the same form or functioning in the same way may each be given the same reference numeral. The elements shown and their relative sizes should not be considered as actual sizes; rather, individual elements such as layers, parts, structural elements, and areas may be shown in an exaggerated size for better visualization and / or better understanding.

[0037] FIGS. 1a and 1b illustrate a schematic diagram of a piezoelectric mirror component (100) according to an embodiment, wherein FIG. 1a illustrates a three-dimensional view of the upper surface of the mirror component (100), and FIG. 1b illustrates a three-dimensional view of the lower surface of the mirror component (100). FIGS. 2a to 2e are schematic diagrams showing the process steps of a process for manufacturing a piezoelectric mirror component (100) according to FIGS. 1a and 1b from the perspective of the upper surface. The following description relates equally to FIGS. 1a and 1b and FIGS. 2a to 2e.

[0038] A piezoelectric mirror component (100) comprises a mirror element (10), a piezoelectric drive ring (20), and a frame element (30). The drive ring (20) surrounds the mirror element (10) and is connected to the mirror element (10) through one or more first torsion spring elements (41). The frame element is connected to the drive ring through one or more second torsion spring elements (42). In the idle state of the mirror component (100), the mirror element (10), the drive ring (20), the frame element (30), and the torsion spring elements (41, 42) are aligned along a plane extending in a first direction indicated by "X" in the drawings and a second direction perpendicular to the first direction indicated by "Y" in the drawings. A piezoelectric layer (50) is provided on at least the drive ring (20) and is positioned between a first electrode (51) and a second electrode (52). The piezoelectric layer (50) preferably has a piezoelectric material based on lead zirconate titanate (PZT) or is made of it.

[0039] As illustrated in FIG. 2a, a carrier (101) is provided to manufacture a mirror component (100), for example, in the form of a silicon wafer or an SOI wafer having a silicon layer thereon and a carrier material made of an electrical insulating material. The carrier (101) is thinned from the bottom surface in the area (102) where the mirror element (10), piezoelectric drive ring (20), frame element (30), and torsion spring elements (41, 42) are arranged, i.e., in the area where the mirror component (100) is mechanically activated. To form the mirror element (10), drive ring (20), and torsion spring elements (41, 42) in the region (102), the carrier is etched as shown in FIG. 2b and thus structured so that a recess (31) is created in the frame element (30) surrounding the drive ring (20), in which the mirror element (10), piezoelectric drive ring (20), frame element (30), and torsion spring elements (41, 42) are disposed. Thus, the frame element (30), drive ring (20), mirror element (10), and torsion spring elements (41, 42) are formed integrally. The recess (31) preferably has a basic polygonal shape, which may be an octagon as shown. Additionally, the recess (31) may have the same rotation axis along the first direction and the second direction.

[0040] As can be seen in FIGS. 1a and 1b, the mirror element (10), the drive ring (20), and the torsion spring elements (41, 42) have a thickness smaller than that of the frame element (30) as a result of the thinning of the carrier (101) described above, where the thickness is designated as "Z" in the drawings and is measured in a third direction perpendicular to the first and second directions. On the upper surface of the carrier (101), an electrical insulating layer having or made of silicon oxide or silicon nitride, for example, may be provided or formed if necessary.

[0041] As illustrated, the drive ring (20) is connected to the mirror element (10) through two first torsion spring elements (41), said two first torsion spring elements are arranged along a straight line in a first direction on two opposing sides of the mirror element (10). Additionally, the drive ring (20) is connected to the frame element (30) through two second torsion spring elements (42), said two second torsion spring elements are arranged along a straight line in a second direction on two opposing sides of the drive ring (20). By this, the suspension of the mirror element (10) on the drive ring (20) is rotated 90° relative to the suspension of the drive ring (20) on the frame element (30).

[0042] The mirror element (10) has a mirror area (11) and a border area (12) surrounding the mirror area (11), and the border area is partially separated from the mirror area (11) by two through holes (13) created by etching as part of the formation of the mirror element (10) described above, and preferably thus at least partially mechanically separated. As illustrated, since the mirror element (10) and the mirror area (11) preferably have a circular base shape, the through holes (13) have the shape of a circular arc. The two through holes (13) are formed to face each other along a first direction. Since the edge region (12) is connected to the mirror region (11) through two connecting regions (14), the two through holes (13) are separated from each other by two connecting regions (14) arranged along the second direction on two opposing sides of the mirror region (11), and the connecting regions are aligned by rotating 90° to the first torsion spring elements (41).

[0043] As can be seen in FIGS. 2c and 2d, the first electrode (51) and the piezoelectric layer (50) are provided continuously to the drive ring (20), the second torsion spring elements (42), and partially to the frame element (30). Contact elements (53) are provided in the form of recesses in the piezoelectric layer (50) as shown in FIG. 2d so that the first electrode (51) portion of the drive ring (20) can make external contact through the first electrode (51) portion of the frame element (30).

[0044] As illustrated in FIG. 2e, a second electrode (52) is provided on a piezoelectric layer (50) on a drive ring (20). The second electrode (52) is structured into a plurality of drive control regions and, as described below, can be divided into at least first and second drive control regions, so the second electrode (52) has a plurality of regions that can be driven independently of each other. For electrical contact of the drive control regions of the second electrode (52), additional contact regions (53) are provided on a frame element (30), and said contact regions are electrically connected to the drive regions through conductor tracks (54) that are also applied to the piezoelectric layer (50).

[0045] Additionally, as can be seen in FIG. 2e, a reflective coating (15) is provided on the mirror area (11), which is preferably a metal coating. A dielectric coating, such as a Bragg mirror, is also possible. The edge area (12) and the connecting area (13) are kept without the reflective coating (15).

[0046] The first torsion spring elements (41) and the second torsion spring elements (42) are formed as so-called torsion beams and have a rectangular shape having a longitudinal direction that rotates along the first direction in the case of the first torsion spring elements (41) and along the second direction in the case of the second torsion spring elements (42). During the operation of the mirror component (100), the torsion spring elements (41, 42) can each perform a torsional motion around a rotation axis, in which case the rotation axis preferably corresponds substantially to the longitudinal direction of each torsion spring element (41, 42). When the mirror element (10) rotates relative to the drive ring (20) around a first rotation axis defined by the first torsion spring elements (41), the first torsion spring elements (41) can preferably apply a restoring force to the mirror element (10) that depends linearly on the rotation angle. When the drive ring (20) and the mirror element (10) rotate relative to the frame element (30) around a second rotation axis defined by the second torsion spring elements (42), the second torsion spring elements (42) can preferably apply a restoring force to the drive ring (20) that depends linearly on the rotation angle.

[0047] In the drive ring (20), each drive control region of the first electrode (51), the piezoelectric layer (50), and the second electrode (52) forms piezoelectric elements that can be driven and controlled independently of each other. By applying a voltage between one or more drive control regions of the first electrode (51) and the second electrode (52), mechanical deformation of the piezoelectric layer (50) and thus the drive ring (20) can be achieved in some regions through an inverse piezoelectric effect, and accordingly, force can be applied to the drive ring (20) and / or the mirror element (10). By applying an alternating current signal having a vibration voltage, a vibration force capable of causing vibration deformation can be applied. As a result, at least a part of the mirror component (100) can be set to vibrate. FIGS. 3a and 3b illustrate a diagram schematically showing a drive control method for process steps of a process for operating the piezoelectric mirror component (100) according to FIGS. 1a and 1b. For clarity, reference numerals in FIGS. 3a and 3b are shown only in the driving control regions of the second electrode. Reference numerals mentioned below that are not shown in FIGS. 3a and 3b relate to FIGS. 1a through 2e.

[0048] By driving the first drive control areas (521) shown in FIG. 3a with a first AC signal having a first frequency and driving the first drive control areas (521') with a first AC signal having a first frequency but with a phase position shifted by 180°, the mirror element (10) can be set to a first torsional vibration relative to the drive ring (20) around a first rotation axis formed by the first torsion spring elements (41). By driving the second drive control areas (522) shown in FIG. 3b with a second AC signal having a second frequency and driving the second drive control areas (522') with a second AC signal having a second frequency but with a phase position shifted by 180°, the drive ring (20) and thus the mirror element (10) can be set to a second torsional vibration relative to the frame element (30) around a second rotation axis formed by the second torsion spring elements (42).

[0049] In particular, since drive control by the first AC signal and drive control by the second AC signal are performed simultaneously, the mirror element (10) and the drive ring (20) simultaneously perform the torsional vibration, so that the mirror element (10) vibrates relative to the drive ring (20) around the first rotation axis at a first frequency, and at the same time, the drive ring (20) together with the mirror element (10) vibrates relative to the frame element (30) around the second rotation axis at a second frequency. The first frequency and the second frequency may be particularly preferably close to the resonance frequency of the torsional vibration or at least the respective resonance frequency depending on the geometric configuration of the elements of the mirror component. Particularly preferably, the first frequency and the second frequency are different. The first and second torsional vibrations may preferably be mechanically decoupled due to the arrangement of the first rotation axis rotating 90° about the second rotation axis.

[0050] Different resonant frequencies can be achieved, in particular, by the non-circular design of the drive ring (20) as illustrated and the fact that while the first torsional vibration is performed solely by the mirror element (10), the second torsional vibration is performed by the drive ring (20) together with the mirror element (10). As can be seen in FIGS. 1a through 2e, the drive ring (20) has a first diameter along a first direction and a second diameter along a second direction, in which case the first diameter is different from the second diameter. In particular, in the illustrated embodiment, the first diameter is larger than the second diameter. Particularly preferably, the drive ring (20) has an elliptical or at least nearly elliptical shape as illustrated.

[0051] The drive ring (20) is bounded by an inner edge facing the mirror element (10) and an outer edge facing in directions along a plane spanning the first and second directions, wherein the inner and outer edges may each have an elliptical or at least a shape close to elliptical. The shape of the outer edge may be defined by the aforementioned first and second diameters, which thus become the first and second outer diameters of the drive ring (20). The inner edge also has a first and second diameter, which thus become the first inner diameter and second inner diameter of the drive ring (20), with the first inner diameter rotating along the first direction and the second inner diameter rotating along the second direction. The ratio of the first outer diameter to the second outer diameter may be the same as or different from the ratio of the first inner diameter to the second inner diameter. In cases where the ratio is different, the drive ring (20) may have a first width along the first direction and a second width along the second direction as illustrated, in which case the first width may be different from the second width. For example, the first width may be smaller than the second width as illustrated.

[0052] Figures 4a to 5e illustrate a simulation study of a piezoelectric mirror component (100) according to the drawings described above.

[0053] To this end, the following desirable parameters were assumed for the mirror component:

[0054] - Mirror element diameter: 1.7mm

[0055] - The first outer diameter of the drive ring (20), i.e., the larger outer diameter: 5.7 mm

[0056] - Distance between the ends of the second torsion spring elements (42) adjacent to the frame element (30): 6.4 mm

[0057] - Thickness of the moving parts of the piezoelectric mirror component, i.e., thickness of the elements within the recess (31): 175μm

[0058] - Thickness of piezoelectric layer: 1μm

[0059] - Assessed damping: 10 -4

[0060] - AC signal voltage: ±2V

[0061] - The square cross-section of the torsion spring element (41, 42), i.e., the thickness is equal to the width.

[0062] - Ignore ESR("equivalent series resistance")

[0063] In FIGS. 4a and 4b, the relative rotation of the mirror element (10) with respect to the drive ring (20) due to the drive control for the first torsional vibration described in relation to FIG. 3a is shown in a three-dimensional view and a side view along the first direction.

[0064] Figure 4c illustrates a simulation diagram for analyzing mechanical performance (upper diagram) and electrical performance (lower diagram) according to the first frequency of the applied first AC signal. For mechanical performance, the mechanical half-scan angle, that is, the maximum rotation angle that the mirror element can reach from the neutral position due to torsional vibration, and the phase delay between the excited first AC signal and the vibrational motion of the mirror element were analyzed. For electrical performance, the magnitude and phase of the composite resistance were analyzed. In the graph, arrows indicate which vertical axis points to which curve. As can be seen in the diagram, the resonance frequency of the first torsional vibration is 28.4 kHz. The diagram represents pure harmonic vibration, that is, a pure torsional vibration mode without significant nonlinear behavior, and in particular, without hysteresis behavior. The drive ring exhibits only very slight movement, specifically negligible movement. For the selected parameters, the field of view (FoV, "field of view") obtained at resonance is approximately 60°, which corresponds to a mechanical half-scan angle of approximately 15°. If necessary, the FoV can be reduced by slightly detuning the first frequency from the resonant frequency.

[0065] In Figures 4d and 4e, the torsion of the mirror element surface is shown as an offset in micrometers based on simulation, and the mechanical load applied to the mirror element during the first torsional vibration at the resonance frequency is shown in GPa. The torsion of the mirror surface during vibration is in the range of ±250 nm, and the highest value occurs only near the connection region. At resonance, the load for a FoV of 60° reaches a maximum value of about 2.5 GPa in the first torsion spring elements. These values ​​are acceptable for silicon. For example, if the FoV is reduced to about 40°, one-third of the original value, the torsion and load can be further reduced because the magnitude of both effects is proportional to the scan angle.

[0066] In Figures 5a to 5e, corresponding to Figures 4a to 4e, simulation results for the drive control described in relation to Figure 3b are displayed for the second torsional vibration, in which case, compared to Figure 4b, a view along the second direction is displayed in Figure 5b. For the second torsional vibration, a resonance frequency of 5.85 kHz occurs, and in this case, the second torsional vibration is also a pure torsional vibration mode around the second torsion spring element without hysteresis behavior. Since the drive control ring moves together with the mirror element to achieve a deflection of the laser beam perpendicular to the deflection described in relation to Figures 4a to 4e, Lissajous scanning is possible through the first and second torsional vibrations. The FoV achievable with the selected parameters is 36°, which corresponds to a mechanical half-scan angle of 9°. The torsion of the mirror surface during vibration is in the range of ±50 nm, and in this case, the highest value occurs only in the edge region of the mirror element, not on the mirror surface. At resonance, the load for a 36° FoV reaches a maximum value of about 1.5 GPa in the second torsion spring elements. Since this value is within the acceptable range in silicon, a 36° FoV is possible for the second torsional vibration.

[0067] Table 1 below summarizes the simulation results discussed in relation to Figures 4a through 5e:

[0068] Torsional vibration 1 (Fast Mode) Part 2 (Slow Mode) Scan direction Y (i.e., parallel to the second direction) X (i.e., parallel to the first direction) Resonance frequency (kHz) 28.4 5.85 Field of view (°) 60 36 Maximum load (GPa) 2.5 1.5 Twist (nm) ±250nm ±50nm

[0069] Accordingly, the first torsion spring elements enable a relatively fast pure torsional vibration mode of the mirror element, whereas the second torsion spring elements, together with the mirror element, enable a relatively slow, likewise pure torsional vibration mode of the drive ring. Both vibrations are free from nonlinear motion and hysteresis. With respect to the following drawings, additional embodiments representing modifications to the mirror component described with respect to the preceding drawings are described. Thus, the subsequent description is essentially related to differences from the preceding description.

[0070] FIGS. 6a and 6b illustrate schematic diagrams of a piezoelectric mirror component (100) according to additional embodiments, wherein the drawings in FIGS. 6a and 6b correspond to the drawings in FIGS. 1a and 1b. FIGS. 7a to 7e schematically illustrate process steps for manufacturing the piezoelectric mirror component (100) according to FIGS. 6a and 6b, wherein the drawings in FIGS. 7a to 7e correspond to the drawings in FIGS. 2a to 2e. The following description relates FIGS. 6a and 6b equally to FIGS. 7a to 7e.

[0071] Compared to the mirror component described in relation to FIGS. 1a through 2e, the mirror component (100) of FIGS. 6a through 7e additionally comprises a frame element (30) and an operating area (33) of the frame element (30) surrounded by an edge portion (32) of the frame element (30). The operating area (33) is directly adjacent to a recess (31), which may be hexagonal as illustrated, for example, and has a thickness smaller than that of the edge portion (31), such as the movable part of the mirror component (100) placed in the recess (31). Additionally, the operating area (33) is partially separated from the edge portion (32) by a plurality of through holes (34).

[0072] In addition to the drive ring (20), a second electrode (52) is additionally provided to the frame element (30) of the operating area (33) and is structured into a plurality of drive control areas. As a result, additional drive control areas may be provided to the frame element (30) in addition to the drive control areas of the drive ring (20), thereby allowing force to be applied to the drive ring (20) in particular in the appropriate drive control described in more detail below. As a result of the larger structural shape shown together with the additional operating area (33), additional or alternative drive for the second torsional vibration of the drive ring (20) may be made possible compared to the previous embodiment.

[0073] As illustrated in FIG. 7a, to manufacture the mirror component (100) illustrated in FIG. 6a and 6b, a larger area (102) of the carrier (101) is thinned out from the bottom surface. In this case, the area (102) corresponds to the area where the mirror element (10), the piezoelectric drive ring (20), the frame element (30), the torsion spring elements (41, 42), and the operating area (33) are placed. To form the mirror element (10), the drive ring (20), the torsion spring elements (41, 42), and the operating area (33) in the area (102), the carrier is etched and structured as in FIG. 7b so that through holes (34) are formed in the frame element (30) in addition to the parts within the recess (31). The non-thin portion of the frame element (30) surrounding the mirror element (10), the piezoelectric drive ring (20), the torsion spring elements (41, 42), the operating area (33), and the through holes (34) forms the edge portion (32), in which case all the mentioned parts are formed integrally. The process steps illustrated in FIGS. 7c through 7e correspond to the process steps described in relation to FIGS. 2c through 2e, in which case the first electrode (51), the piezoelectric layer (50), and the second electrode (52) are also provided in the operating area (33) of the frame element (30) to form additional piezoelectric elements. The contact elements (53) are separated from the operating area (33) by the through holes (34) and are placed in the edge portion (32). As a result, the contact elements (53) are at least partially mechanically separated from the operating area (33).

[0074] As described in relation to FIGS. 3a and 3b, each driving control region of the first electrode (51), the piezoelectric layer (50), and the second electrode (52) in the drive ring (20) and the frame element (30) forms piezoelectric elements that can be driven independently of each other. FIGS. 8a to 8e schematically illustrates an exemplary driving method through the first and second driving control regions (521, 521', 522, 522') for the operation method of the piezoelectric mirror component (100) according to FIGS. 6a to 7e.

[0075] FIGS. 8a to 8c show first drive control regions (521 and 521'), wherein the first drive control regions (521) are driven by a first alternating current signal having a first frequency, and the first drive regions (521') are driven by a first alternating current signal having a first frequency but driven in a state where the phase position is shifted by 180°, so as to set the mirror element (10) to vibrate first torsionally relative to the drive ring (20) around a first rotation axis formed by the first torsion spring elements (41). FIGS. 8d and 8e show second drive control regions (522 and 522'), in which the second drive control regions (522) are driven by a second AC signal having a second frequency and the second drive control regions (521') are driven by a second AC signal having a second frequency but driven in a state where the phase position is shifted by 180°, so as to set the drive ring (20) together with the mirror element (10) to vibrate a second torsional vibration relative to the frame element (30) around a second rotation axis formed by the second torsion spring elements (42). In particular, since one of the drive control method of FIG. 8a combined with the drive control method of FIG. 8d and the drive control method of FIG. 8b and 8c combined with the drive control method of FIG. 8e can be used here, the drive control regions of the second electrode (52) can be clearly assigned to one of the two torsional vibrations.

[0076] Figures 9a through 12e illustrate simulation tests similar to those described in relation to Figures 4a through 5e, wherein, in addition to the preferred parameters assumed above in relation to Figures 4a through 5e, the dimensions of the mirror component including the frame element were assumed to be approximately 11 x 8 mm². All simulation test results showed a pure torsional vibration mode without hysteresis behavior.

[0077] FIGS. 9a to 9e relate to drive control for generating the first torsional vibration shown in FIG. 8a. As a result, a resonant frequency of 24.39 kHz and a FoV of approximately 42° are generated, which corresponds to a mechanical half-scan angle of approximately 10.7°. The torsional distortion of the mirror area during vibration is ±23.8 nm, so the mechanical load is sufficiently low.

[0078] FIGS. 10a to 10e relate to drive control for generating the first torsional vibration shown in FIG. 8b. The resonance frequency defined by mechanical boundary conditions is 24.39 kHz, as in the case of FIG. 8a, but a FoV of 48° is achieved, which corresponds to a mechanical half-scan angle of 12°. The torsion of the mirror surface during vibration is ±26.8 nm, so the mechanical load is sufficiently low.

[0079] FIGS. 11a to 11e relate to the drive control shown in FIG. 8d to generate a second torsional vibration. As a result, a resonant frequency of 4.88 kHz and a FoV of approximately 75° are generated, which corresponds to a mechanical half-scan angle of approximately 18.7°. The torsion of the mirror area during vibration is ±7.6 nm, so the mechanical load is sufficiently low.

[0080] FIGS. 12a to 12e relate to the drive control shown in FIG. 8e to generate a second torsional vibration. This again generates a resonant frequency of 4.88 kHz and a FoV of about 45°, which corresponds to a mechanical half-scan angle of about 11.4°. The torsion of the mirror area during vibration is ±4.5 nm, so the mechanical load is sufficiently low.

[0081] FIGS. 13a and 13b illustrate schematic diagrams of a piezoelectric mirror component (100) according to additional embodiments forming a variation of the mirror component described in relation to FIGS. 6a through 7e. FIGS. 14a through 14e illustrate schematic diagrams of process steps for manufacturing the piezoelectric mirror component (100) according to FIGS. 13a and 13b, corresponding to the process steps described in relation to FIGS. 7a through 7e. The following description relates in the same way to FIGS. 13a and 13b and FIGS. 14a through 14e.

[0082] Compared to the embodiments of FIGS. 6a through 7e, the embodiments of the mirror component (100) shown in FIGS. 13a through 14e have a smaller operating area (33) that is rather rectangular in shape. In this embodiment, the recess (31) is formed in a rectangular shape and preferably a square shape.

[0083] FIG. 15 illustrates a schematic diagram of an exemplary control method through second drive control regions (522, 522') for the operation process of a piezoelectric mirror component (100) according to FIG. 13a to 14e, wherein the second drive control regions (522) are driven by a second AC signal having a second frequency, and the second control regions (522') are driven by a second AC signal having a second frequency, but driven in a state where the phase position is shifted by 180°, which is intended to set the drive ring (20) together with the mirror element (10) to a second torsional vibration relative to the frame element (30) around a second rotation axis formed by the second torsion spring elements (42). For example, the drive control method shown in FIG. 8a can be used to generate a first torsional vibration.

[0084] FIGS. 16a to 16e illustrate simulation tests similar to those described in FIGS. 4a to 5e, related to the drive control shown in FIG. 15. As a result of the simulation tests, a pure torsional vibration mode without hysteresis behavior appeared for the investigated second torsional vibration. The resonance frequency of this mode is 5.51 kHz, the FoV is 67°, and the mechanical half-scan angle corresponds to approximately 17.8°. The torsional deformation of the mirror area during vibration is ±7.6 nm, indicating that the mechanical load is sufficiently low.

[0085] According to some preferred embodiments, the piezoelectric mirror component described above has piezoelectric thin film elements that operate by resonating the mirror elements in a first direction and a second direction. The result is so-called Lissajous scanning. This enables higher image resolution with the same resonant frequency for a faster deflection axis compared to raster scanning, namely the first rotation axis of the embodiment described above. Subsequent parameters resulting from the required image resolution and refresh rate can be specifically set according to the application:

[0086] - Diameter of the mirror element

[0087] - Maximum deflection angle in each orthogonal deflection direction. If the diameter of the mirror is used as a through hole, diffraction-limited image resolution can be obtained.

[0088] - Operating frequency in each direction. As a result, image resolution and refresh rate can be evaluated by comparing them through fine-tuning the frequency ratio between the two directions.

[0089] - It maintains the flatness of the mirror at all operating points to prevent imaging errors, pixel blurring, and stain patterns.

[0090] - To ensure a stable frequency ratio, the mirror element must vibrate harmoniously around two rotation axes by selecting an appropriate amplitude of the AC signal so that the resonant frequency does not depend on the amplitude.

[0091] - For the fine-tuning mentioned above to be possible, the resonance bandwidth of the mirror element must not be too narrow.

[0092] - Compact structural shape

[0093] - Impact resistance

[0095] In particular, the mirror component described herein can provide a 2D design capable of fully satisfying all requirements for a resolution of 1024 x 768 pixels. The mirror component may particularly preferably include one or more or all of the features mentioned subsequently:

[0096] - Two-way torsional vibration ensures harmonic vibration even at larger amplitudes.

[0097] - High process costs can be avoided because the thickness of all movable parts is the same.

[0098] - The two frequencies are clearly different. This means that the suspension of the mirror element can be optimized in one direction. Additionally, the thickness can be slightly reduced.

[0099] - The thickness is determined along with the material from the diameter of the desired mirror element, suspension, desired frequency, and required flatness.

[0100] - The dimensions of the first torsion spring elements are determined from the already defined actual mirror elements, the required frequency and deflection, and the load capacity of the material.

[0101] - The second torsion spring elements are mounted outside the drive ring and preferably rotated 90° relative to the first torsion spring elements.

[0102] - The drive for the second torsional vibration is preferably in a movable drive ring. This has the advantage of a compact structural shape, and the frequency is also reduced by the moment of inertia of the drive ring.

[0104] Additionally, the piezoelectric mirror component described in this specification may have one or more of the advantages subsequently mentioned:

[0105] - Both vibrations are implemented through torsion spring elements, meaning the vibrations remain harmonized even at high deflection. This prevents the disharmony caused by suspension bending in many other designs, such as the so-called "Quad-Pod" design.

[0106] - Second torsion spring elements for slow vibration are positioned outside the drive ring. The drive ring moves together. This allows the drive to be optimized for the first torsion vibration without significantly affecting the characteristics of the second torsion vibration.

[0107] - Two vibrations can share a single drive ring. As a result, a very compact structural shape is provided.

[0108] - The elliptical symmetry of the drive ring provides more degrees of freedom to individually adjust the characteristics of two orthogonal torsional vibrations, particularly the frequency and deflection angle. For example, the ellipticity of the drive ring can be optimized to maintain excellent drive control of the first torsional vibration.

[0110] In a particularly preferred embodiment, the mirror component has the following characteristics, and by these characteristics, a resolution of 1024 x 768 pixels with an overall screen refresh rate of less than 50Hz can preferably be achieved:

[0111] - Material: Silicone

[0112] - Metal of the first electrode: Platinum

[0113] - Metal of the second electrode: Gold

[0114] - Metal of reflective coating: Aluminum

[0115] - Silicon thickness: 175μm

[0116] - Diameter of the mirror area with reflective coating: 1.7mm

[0117] - Torsion spring element: Width 175μm, Length 1mm

[0118] - Drive ring: Width 0.7 ~ 0.95mm

[0119] - Piezoelectric layer material: PZT with a thickness in the range of 1 to 2 μm.

[0121] In a more particularly preferred embodiment, the mirror component has the following characteristics, by which preferably a resolution of 1024 x 768 pixels with an overall screen refresh rate of less than 50Hz can be achieved:

[0122] - Material: Silicone

[0123] - Metal of the first electrode: Platinum

[0124] - Metal of the second electrode: Gold

[0125] - Metal of reflective coating: Aluminum

[0126] - Silicon thickness: 150μm

[0127] - Elliptical mirror area with reflective coating

[0128] - Elliptical axis length of the mirror area: 1.6mm x 1.7mm

[0129] - Torsion spring element: Width 150μm, Length 0.6 ~ 0.8mm

[0130] - Drive ring: Width 0.7 ~ 1.35mm

[0131] - Piezoelectric layer material: PZT with a thickness in the range of 1 to 2 μm.

[0133] FIG. 17 illustrates a schematic diagram of a projection device (1000) according to an additional embodiment having a piezoelectric mirror component (100) according to the preceding description. Additionally, the projection device is equipped with a laser light source (200) that emits laser light (201) during operation.

[0134] For example, the laser light source (200) may be a so-called RGB light source capable of emitting red, green, and blue laser light. To this end, the laser light source (200) may have, for example, three laser diodes or a group of laser diodes that can be modulated accordingly. The laser beams may be superimposed, for example, at a beam combiner (202), so that the beam of the combined laser beam (201') is irradiated onto a piezoelectric mirror component (100) and reflected from that location to a desired image area. The laser light source (200) may be driven and controlled, for example, through a laser control electronic device (206), and may modulate the amplitude of the laser light over time, for example.

[0135] The piezoelectric mirror component (100) may be driven and controlled via a mirror element control electronic device (203) to create a desired Lissajous shape capable of scanning a desired image area, for example. Additionally, a sensor electronic device (204) may be provided to detect the position and / or frequency of the mirror element of the mirror component (100), preferably in real time. Additionally, an image processing electronic device (205) may be provided to control the overall image display, for example. This may correspond to converting image or film information into control signals for the laser light source (200) and the mirror component (100), particularly including temporal synchronization between the mirror element position and the amplitude of a different laser.

[0136] FIGS. 18a through 18e illustrate schematic diagrams of measurements for determining the position and / or frequency of components of a piezoelectric mirror component according to some embodiments. Such measurements may be provided in conjunction with a method of operation of the mirror device. For example, such measurements may be provided in connection with the sensor electronics (204) described above.

[0137] For example, during the operation of the piezoelectric mirror component (100), a second frequency can be measured from a first alternating current signal. As illustrated in FIG. 18a, this can be achieved, for example, by using a suitable frequency filter (71) in the drive supply line (70), so no additional line is required.

[0138] Additionally, as illustrated in FIGS. 18b and 18c, it may be possible to provide third drive control areas (523) in addition to first and second drive control areas capable of measuring piezoelectric signals through the piezoelectric effect. The third drive control area (523), which may also be called a sensor element or sensor area, may be provided at an appropriate location to obtain a particularly good signal.

[0139] For example, the third drive control area (523) may be positioned on the drive ring (20), for example, close to the first torsion spring element (42), or close to the second torsion spring element (42) as shown in FIG. 18b. Being positioned "close to the torsion spring element" may mean, in particular, that the third drive control area is positioned close to or adjacent to the base of the relevant torsion spring element, and that the first and second drive control areas are not positioned closer to the corresponding torsion spring element than the third drive control area. In FIG. 18b, purely for illustrative purposes, four third drive control areas (523) are provided, which are positioned symmetrically with respect to the first and second torsion spring elements (42).

[0140] Additionally, a third drive control area (523) may also be formed in the frame element (30) as illustrated in FIG. 18c. This allows the drive ring (20) to be fully utilized in the drive control areas (521, 521', 522, 522'). Furthermore, the third drive control areas (523) in the frame element (30) are easy to manufacture and easy to contact because there is no need to route the additional conductor tracks (54) through the second torsion spring elements (42) for contact with the additional conductor tracks.

[0141] As illustrated in FIG. 18c, for example, four third drive control regions (523) may be symmetrically arranged on the first and second torsion spring elements (42) as sensor elements (Sa, Sb, Sc, Sd). The sensor elements (Sa, Sb, Sc, Sd) may be contacted by contact elements (53a, 53b, 53c, 53d) and conductor tracks (54).

[0142] For example, as illustrated, two third drive control regions (523) forming sensor elements (Sa and Sb) may be placed on the base of one of the two second torsion spring elements (42), and two additional third drive control regions (523) forming sensor elements (Sc and Sd) may be placed symmetrically with respect to the axis formed by the second torsion spring elements on the base of the other of the two second torsion spring elements (42). The frame element (30) may be thinned down below the second drive control regions (523) and may have the same thickness as, for example, the drive ring (20) to allow mechanical movement of the third drive control regions (523). For example, the frame element (30) may have a thickness reduced to the same thickness as the drive ring (20) in the dotted areas (35) where the third drive control elements (523) are located, whereas the rest of the frame element (30) or at least the edge portion of the frame element may have a greater thickness than the areas (35) as described above. That is, the third operating areas are preferably placed in one or more areas with reduced thickness compared to the rest of the frame member (30) or at least compared to the edge portion of the frame member (30).

[0143] Due to the arrangement of the sensor elements (Sa, Sb, Sc, and Sd) described on the frame element (30), bidirectional deflection, namely deflection for the first torsion elements (41) and deflection for the second torsion elements (42), can be detected simultaneously. To this end, a linear combination of the signals of the four sensor elements (Sa, Sb, Sc, Sd) formed by the third drive control area (523) may be used. If the signals of the sensor elements are denoted as Sa, Sb, Sc, and Sd for brevity, the vibration for the first torsion spring elements (41) is one or more linear combinations of the signals of the sensor elements (Sa, Sb, Sc, and Sd), |Sa+Sb|, |Sc+Sd|, and |Sa-Sc| The deflection of the second torsion spring elements (42) can be detected by |Sb-Sd| and one or more linear combinations of signals of the sensor elements (Sa, Sb, Sc and Sd), |Sa+Sc|, |Sb+Sd|, |Sa-Sb| and |Sc-Sd|. The measurement accuracy can be increased by using the aforementioned various linear combinations. Alternatively, for example, it may be possible to have only two third drive control regions (523) as this is sufficient in principle to obtain the desired information. For example, the third drive control regions (523) may only have a third drive control region that forms the sensor elements (Sa and Sb), forms the sensor elements (Sa and Sc), forms the sensor elements (Sc and Sd), or forms the sensor elements (Sb and Sd). That is, if there are only two sensor elements, the two sensor elements must not be positioned diagonally opposite each other, but must be positioned on the same side with respect to the first torsion spring elements (41) or the second torsion spring elements (42).

[0144] Furthermore, there may be first and / or second drive control regions that are alternately used in a time-division multiplexing process to drive the mirror element or drive ring and to measure the piezoelectric signal. To this end, as illustrated in FIG. 18c, for example, at least some first or second drive control regions (521, 521', 522, 522') may exist and are provided simultaneously as a third drive control region. In particular, this may mean that driving and positioning are performed at different times. This can be achieved, for example, through appropriate pulse width modulation, in which case the mirror element is driven alternately for a specific period and the measurement is performed for a shorter period. Due to the high mechanical quality, the deflection of the mirror element is almost not lost.

[0145] Additionally, for position and / or frequency measurement, as illustrated in FIG. 18d, at least two electrode elements (61, 61', 62, 62') may be present, which form a capacitor having variable capacitance when the mirror element (10) or drive ring (20) is moved, in which case the capacitance of the capacitor is measured. The electrode elements (61, 61', 62, 62') may be formed, for example, by conductor track components. For example, the first electrode element (61) may be placed on the frame element (30), while the second electrode element (62) may be placed on the drive ring (20) adjacent to the first electrode element (61). When the drive ring (20) moves relative to the frame element (30), the distance between the electrode elements (61, 62) may change, and as a result, the capacitance of the capacitor formed by the electrode elements (61, 62) may change. Therefore, electrode elements can also be placed in, for example, the drive ring (20) and the mirror element (10).

[0146] For example, it may be possible to place electrode elements (61', 62') on two opposing sides of the drive ring (20) on the frame element (30). Then, the drive ring (20) can act as a moving dielectric between the electrode elements (61', 62') during movement. Thus, two electrode elements may be placed on the drive ring (20) on opposing sides of the mirror element (10).

[0147] In particular, zero pass of the drive ring (20) and / or mirror element (10) can also be determined during these capacitive measurements. To avoid a capacitive short circuit, the first electrode can be appropriately structured.

[0148] Along with the drawings described above, a circular mirror area (11) is shown in succession. Alternatively, the mirror area (11) and thus the reflective coating (15) may also be elliptical, as shown in the partial enlarged cross-sectional view of the mirror component in FIG. 19a and 19b, and may have a larger elliptical axis (G) and a smaller elliptical axis (K). Preferably, as shown in FIG. 19a, the larger elliptical axis (G) is oriented along the first direction and the smaller elliptical axis (K) is oriented along the second direction. Alternatively, as shown in FIG. 19b, the larger elliptical axis (G) may be oriented along the second direction and the smaller elliptical axis (K) along the first direction. In the case of the elliptical mirror area (11), the through holes (13) are in the shape of elliptical arcs. For example, the ratio of the larger elliptical axis (G) to the smaller elliptical axis (K) may be greater than 1, or greater than or equal to 1.02, or greater than or equal to 1.04, or greater than or equal to 1.06, or less than or equal to 1.1, or less than or equal to 1.08, or less than or equal to 1.07.

[0149] The features and embodiments described in relation to the drawings may be combined with one another according to additional embodiments, even if not all combinations are explicitly described. Additionally, the embodiments described in relation to the drawings may have alternative or additional features as described in the general section.

[0150] The present invention is not limited to this description due to the description based on the embodiments. Rather, the present invention includes not only novel features but also combinations of features, and in particular, includes combinations of features described in the claims, even if such features or combinations themselves are not explicitly described in the claims or embodiments. Explanation of the symbols

[0151] 10: Mirror element 11: Mirror area 12: border area 13: Penetrating hole 14: Connection area 15: Reflective coating 20: Drive ring 30: Frame elements 31: Recess 32: edge part 33: Operating area 34: Penetrating hole 35: area 41: First torsion spring element 42: Second torsion spring element 50: piezoelectric layer 51: First electrode 52: Second electrode 521, 521': 1st drive control area 522, 522': 2nd drive control area 523: Third drive control area 53, 53a, 53b, 53c, 53d: contact element 54: conductor track 61, 61': electrode element 62, 62': electrode element 70: supply line 71: Frequency filter 100: piezoelectric mirror component 101: suitcase 102: area 200: Laser light source 201, 201': Laser light 202: Beam combiner 203: Mirror element control electronic device 204: Sensor electronic device 205: Image processing electronic device 206: Laser control electronic device 1000: Projection device G, K: elliptical axis Sa, Sb, Sc, Sd: Sensor element

Claims

Claim 1 A piezoelectric mirror component (100) comprising: a mirror element (10); a piezoelectric drive ring (20) surrounding the mirror element (10) and connected to the mirror element (10) through one or more first torsion spring elements (41); and a frame element (30) connected to the drive ring (20) through one or more second torsion spring elements (42), wherein the one or more second torsion spring elements (42) extend from the drive ring (20) to the frame element (30). Claim 2 A piezoelectric mirror component according to claim 1, wherein a first electrode (51) and a second electrode (52) structured with a plurality of drive control regions are provided on the drive ring (20), and a piezoelectric layer (50) is disposed between the first electrode (51) and the second electrode (52), and at least partially the first electrode (51) and at least partially the piezoelectric layer (50) are provided on the frame element (30), and the second electrode (52) is provided in an operating region (33) surrounded by an edge portion (32) of the frame element (30), and the operating region (33) has a thickness smaller than that of the edge portion (32). Claim 3 In paragraph 2, a piezoelectric mirror component in which the operating area (33) is partially separated from the edge portion (32) by one or more through holes (34). Claim 4 A piezoelectric mirror component according to paragraph 2, wherein contact elements (53) for driving control of the first electrode (51) and the second electrode (52) are provided in the frame element (30), and driving control regions of the second electrode (52) are connected to the contact elements (53) through conductor tracks (54) extending across the one or more second torsion spring elements (42). Claim 5 A piezoelectric mirror component according to any one of claims 1 to 4, wherein the drive ring (20) has a first diameter along a first direction and a second diameter along a second direction perpendicular to the first direction, and the first diameter is larger than the second diameter. Claim 6 A piezoelectric mirror component according to any one of claims 1 to 4, wherein the mirror element (10) and the drive ring (20) have a thickness smaller than one or more edge portions (32) of the frame element (30), and the frame element (30), the drive ring (20), the mirror element (10), and the torsion spring elements (41, 42) are formed integrally. Claim 7 A piezoelectric mirror component according to any one of claims 1 to 4, wherein the drive ring (20) has an elliptical shape. Claim 8 A piezoelectric mirror component according to claim 5, wherein one or more first torsion spring elements (41) are arranged along the first direction and one or more second torsion spring elements (42) are arranged along the second direction. Claim 9 A piezoelectric mirror component according to any one of claims 1 to 4, wherein the drive ring (20) is connected to the mirror element (10) through two first torsion spring elements (41) arranged along a straight line on two opposing sides of the mirror element (10), and the drive ring (20) is connected to the frame element (30) through two second torsion spring elements (42) arranged along a straight line on two opposing sides of the drive ring (20). Claim 10 A piezoelectric mirror component according to any one of claims 1 to 4, wherein the mirror element (10) has a mirror area (11) and a border area (12) surrounding the mirror area (11), the border area (12) is partially separated from the mirror area (11) by two through holes (13), and the border area (12) is connected to the mirror area (11) through two connecting areas (14). Claim 11 A piezoelectric mirror component according to claim 10, wherein a reflective coating (15) is provided on the mirror area (11), and the reflective coating (15) is not provided on the border area (12) and the connecting area (14). Claim 12 In item 10, a piezoelectric mirror component in which the mirror area (11) is formed in a circular or elliptical shape. Claim 13 A piezoelectric mirror component according to any one of claims 1 to 4, wherein the frame element (30) surrounds the drive ring (20) and has a recess (31) penetrating the frame element (30), and the drive ring (20) and the one or more second torsion spring elements (42) are disposed within the recess (31). Claim 14 In paragraph 13, the piezoelectric mirror component having a polygonal basic shape in which the recess (31) is a hexagon or an octagon. Claim 15 A piezoelectric mirror component according to any one of claims 1 to 4, wherein at least two electrode elements (61, 61', 62, 62') are provided, and said electrode elements form a capacitor having a variable capacitance during movement of the mirror element (10) or the drive ring (20). Claim 16 A piezoelectric mirror component according to any one of claims 1 to 4, wherein at least two third drive control regions (523) are disposed on the frame element (30) on the same side with respect to the one or more first torsion spring elements (41) or the one or more second torsion spring elements (42), and the third drive control region (523) is a sensor region configured to measure a piezoelectric signal through a piezoelectric effect. Claim 17 In claim 16, the third drive control regions (523) are positioned in one or more regions (35) of the frame element (30), and the one or more regions (35) have a thickness smaller than one or more edge portions (32) of the frame element (30), a piezoelectric mirror component. Claim 18 A piezoelectric mirror component according to claim 17, wherein four of the third drive control regions (523) are arranged symmetrically with respect to the first torsion spring elements (41) and the second torsion spring elements (42) as sensor elements (Sa, Sb, Sc, Sd). Claim 19 A piezoelectric mirror component according to claim 18, wherein two of the four third drive control regions (523) form two sensor elements (Sa, Sb) and are positioned at the base of one of the two second torsion spring elements (42), and the other two of the four third drive control regions (523) form two other sensor elements (Sc, Sd) and are positioned symmetrically with respect to the axis formed by the second torsion spring elements (42) at the base of the other of the two second torsion spring elements (42). Claim 20 A piezoelectric mirror component, wherein, in any one of claims 1 to 4, measures are provided to achieve at least one of positioning the mirror element (10), positioning the drive ring (20), and determining the frequency of one or two torsional vibrations. Claim 21 A method of operating a piezoelectric mirror component (100) according to any one of claims 1 to 4, wherein the mirror element (10) is set to vibrate a first torsionally by a first electric alternating current signal having a first frequency acting on first drive control areas (521, 521'), and the drive ring (20) is set to vibrate a second torsionally by a second electric alternating current signal having a second frequency acting on second drive control areas (522, 522'). Claim 22 A method of operation of a piezoelectric mirror component (100) according to claim 21, wherein the second frequency is measured from the first alternating current signal and the first frequency is measured from the second alternating current signal during the operation of the piezoelectric mirror component (100). Claim 23 A method of operation of a piezoelectric mirror component (100), wherein, in paragraph 21, third drive control areas (523) in which a piezoelectric signal is measured are provided. Claim 24 A method of operation of a piezoelectric mirror component (100), wherein at least two electrode elements (61, 61', 62, 62') are provided, said electrode elements form a capacitor having a variable capacitance during movement of said mirror element (10) or said drive ring (20), and said capacitance of said capacitor is measured. Claim 25 A method of operation of a piezoelectric mirror component (100), wherein at least one of first drive control regions (521, 521') and second drive control regions (522, 522') is provided, and said drive control regions are alternately used to drive the mirror element (10) or the drive ring (20) and to measure a piezoelectric signal in a time-division multiplexing process. Claim 26 A projection device (1000) comprising: a laser light source (200); and a piezoelectric mirror component (100) according to any one of claims 1 to 4.

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