Micro-electro-mechanical system (MEMS) devices and methods of operating the same

Abstract

This disclosure relates to microelectromechanical systems (MEMS) devices and methods of operation thereof. A MEMS device is provided. The MEMS device includes a movable structure configured to oscillate about a plurality of oscillating axes. Additionally, the MEMS device includes a comb-driven actuator configured to cause motion of the movable structure about the plurality of oscillating axes. Furthermore, the MEMS device includes a sensor configured to measure the motion of the movable structure about the plurality of oscillating axes. The MEMS device includes control circuitry configured to perform one or more of the following: a) during a measurement time window in which the sensor measures the motion of the movable structure about one of the oscillating axes, controlling the comb-driven actuator to maintain corresponding drive voltages for other oscillating axes at constant levels; and b) discarding the motion measured by the sensor for one of the oscillating axes during a sensing suppression time window initiated by a switching event of the drive voltage for any of the oscillating axes.

Description

Technical Field

[0001] This disclosure relates to microelectromechanical systems (MEMS). In particular, examples of this disclosure relate to MEMS devices and methods of operating MEMS devices. Background Technology

[0002] Multi-axis MEMS mirrors are used for precise control in various applications, such as laser beam scanning and lidar systems. They operate using the electrostatic force generated by interlaced comb teeth on the rotor and stator (often referred to as comb actuation), which facilitates both actuation and sensing. While these systems efficiently achieve motion and detection, they suffer from inherent crosstalk problems. This inherent crosstalk problem arises because the proximity of the comb actuation often generates invalid sensing signals during changes in the drive voltage. This problem is more pronounced in multi-axis systems, where multiple oscillating axes can cause mutual electrical interference, thus compromising the reliability of the measurement signal. A voltage change on one axis can affect other axes, potentially causing the system to lose observability.

[0003] Therefore, there may be a need to overcome the above-mentioned shortcomings. Summary of the Invention

[0004] This need is met by the subject matter of the independent claims. Further embodiments are given in the dependent claims.

[0005] According to a first aspect, this disclosure provides a MEMS device. The MEMS device includes a movable structure configured to oscillate about a plurality of oscillating axes. Additionally, the MEMS device includes an actuator configured to cause motion of the movable structure about the plurality of oscillating axes. Furthermore, the MEMS device includes a sensor configured to measure the motion of the movable structure about the plurality of oscillating axes. The MEMS device includes control circuitry configured to perform one or more of the following: a) during a measurement time window in which the sensor measures the motion of the movable structure about one of the oscillating axes, controlling the actuator to maintain corresponding drive voltages for the other oscillating axes at constant levels; and b) discarding the motion measured by the sensor for one of the oscillating axes during a sensing suppression time window initiated by a switching event of the drive voltage for any of the oscillating axes.

[0006] According to a second aspect, this disclosure provides a method for operating a MEMS device. The method includes using an actuator of the MEMS device to induce motion of a movable structure of the MEMS device about a plurality of oscillating axes. Additionally, the method includes using a sensor of the MEMS device to sense the motion of the movable structure about the plurality of oscillating axes. The method further includes performing one or more of the following: a) while measuring the motion of the movable structure about one of the oscillating axes, controlling the actuator to maintain corresponding drive voltages for the other oscillating axes at constant levels; and b) discarding the motion measured by the sensor for one of the oscillating axes within a sensing suppression time window, the sensing suppression time window being initiated by a switching event of the drive voltage for any of the oscillating axes.

[0007] According to a third aspect, this disclosure provides a non-transitory machine-readable medium having a program stored thereon, the program having program code for performing the method described in the second aspect when the program is executed on a processor or programmable hardware.

[0008] According to the fourth aspect, this disclosure provides a program, program code of which, when executed on a processor or programmable hardware, performs the method described according to the second aspect.

[0009] In some embodiments, the actuator is a comb-driven actuator.

[0010] Those skilled in the art will recognize the additional features and advantages upon reading the following detailed description and viewing the accompanying drawings. Attached Figure Description

[0011] This disclosure is illustrated in the accompanying drawings by way of example rather than limitation, in which similar reference numerals refer to similar or identical elements. The dimensions of the elements in the drawings are not necessarily drawn to scale relative to each other. Features of the various illustrated examples can be combined unless mutually exclusive.

[0012] Figure 1 An example of a MEMS device is illustrated;

[0013] Figure 2 An example of a timing diagram is shown;

[0014] Figure 3 The flowchart illustrates an example of a method for operating a MEMS device. Detailed Implementation

[0015] Figure 1 The MEMS device 100 is schematically illustrated.

[0016] MEMS device 100 includes a movable structure 110 configured to oscillate about multiple oscillation axes. An oscillation axis is an imaginary line about which the movable structure 110 can pivot or rotate. The oscillation axis extends through MEMS device 100 and defines a directional plane of oscillation. In other words, the movable structure 110 is configured to pivot back and forth along more than one directional plane of oscillation. The orientation and position of the oscillation axes define the manner and range of motion that the movable structure 110 can achieve, allowing it to perform various rotational or pivotal movements. Multiple oscillation axes allow for complex and controlled oscillations, enabling MEMS device 100 to perform advanced functions in applications such as laser beam scanning, lidar systems, and precision measurement.

[0017] The movable structure 110 is configured to oscillate relative to the stator (static structure) 105 of the MEMS device 100. The stator 105 is the stationary portion (substrate, base) of the MEMS device 100. The stator 105 can be made of various materials, such as one or more semiconductor materials (e.g., silicon, polycrystalline silicon, or silicon carbide), glass, metal, metal alloy, and ceramics (e.g., alumina or zirconium oxide). The movable structure 110 can be made of the same material as the stator 105 or a different material.

[0018] exist Figure 1 In the example, movable structure 110 is configured to oscillate about two oscillation axes. However, it should be noted that in other examples, movable structure 110 may be configured to oscillate about more than two oscillation axes. These two oscillation axes are perpendicular to each other. These two oscillation axes extend perpendicular to the thickness direction of stator 105. Stator 105 serves as a mechanical support for movable structure 110. Movable structure 110 is suspended from stator 105 by a first suspension structure 111. Specifically, a first portion 113 of movable structure 110 is suspended from stator 105 by the first suspension structure 111. The first suspension structure 111 may include one or more of a hinge, spring, or flexure to allow movable structure 110 to rotate relative to stator 105 about the first of the two oscillation axes. A second portion 114 of movable structure 110 is suspended from the first portion 113 of movable structure 110 by a second suspension structure 112. Similar to the first suspension structure 111, the second suspension structure 112 may include one or more of a hinge, a spring, or a flexure to allow the second portion 114 of the movable structure 110 to rotate relative to the first portion 113 of the movable structure 110 (and therefore relative to the stator 105) about the second oscillating axis (the other oscillating axis) of the two oscillating axes.

[0019] The movable structure 110, particularly the second portion 114 of the movable structure 110, can take on any shape. For example, when viewed from the top or bottom of the MEMS device 100, the second portion of the movable structure 110 can appear rectangular, square, circular, or elliptical. Figure 1 As illustrated, the second part of the movable structure 110 may have a flat (planar) surface. Alternatively, the second part of the movable structure 110 may have a curved (e.g., spherical, cylindrical, parabolic, convex, concave, or freeform) surface.

[0020] Additionally, the MEMS device 100 includes actuators, such as a comb-driven actuator 120, configured to cause motion of the movable structure 110 about a plurality of oscillating axes. For example, the comb-driven actuator 120 may be configured to cause motion of the movable structure 110 by electrostatic force. The comb-driven actuator 120 includes comb-shaped actuation electrode structures (also referred to as "comb teeth of the comb-driven actuator 120") interleaved with comb-shaped electrode structures of the movable structure 110 (also referred to as "comb teeth of the movable structure 110"). The comb-shaped actuation electrode structures of the comb-driven actuator 120 and the comb-shaped electrode structures of the movable structure 110 are made of conductive materials (e.g., one or more of semiconductor materials, metals, or metal alloys). By applying a voltage difference across these comb-shaped electrode structures, an electrostatic attraction can be generated, driving the movement of the movable structure 110 relative to the stator 105.

[0021] Because in Figure 1 In the example, the movable structure 110 is configured to oscillate about two oscillation axes, so the comb-driven actuator 120 includes a first comb-shaped actuation electrode structure that is interleaved with the first comb-shaped electrode structure of the movable structure 110. For example, the first comb-shaped actuation electrode structure may be formed on the stator 105, and the first comb-shaped electrode structure of the movable structure 110 may be formed on the first portion 113 of the movable structure 110 to cause movement of the movable structure 110 about the first oscillation axis. The comb-driven actuator 120 may include a first drive circuit device 121 configured to apply a potential to the first comb-shaped actuation electrode structure to drive the movable structure 110 (specifically the first portion 113 of the movable structure 110) to oscillate about the first oscillation axis.

[0022] Similarly, the comb-driven actuator 120 includes a second comb-shaped actuation electrode structure that is interleaved with the second comb-shaped electrode structure of the movable structure 110. For example, the second comb-shaped actuation electrode structure may be formed on a first portion 113 of the movable structure 110, and the second comb-shaped electrode structure of the movable structure 110 may be formed on a second portion 114 of the movable structure 110 to cause movement of the movable structure 110 about a second oscillation axis. The comb-driven actuator 120 may include a second drive circuit device 122 configured to apply a potential to the second comb-shaped actuation electrode structure to drive the movable structure 110 (particularly the second portion 114 of the movable structure 110) to oscillate about the second oscillation axis.

[0023] The first driving circuit device 121 and the second driving circuit device 122 can be electrically coupled to the first comb-shaped actuation electrode structure and the second comb-shaped actuation electrode structure via multiple conductive paths, traces, or channels. For the sake of simplicity, Figure 1 The comb-shaped drive actuator 120 is schematically shown in the figure, and Figure 1 The details of the comb-shaped electrode structure and other related features are not illustrated in the diagram. Figure 1 In the example, the comb-driven actuator 120 is illustrated as a separate element from the stator 105 and the movable structure 110. However, this disclosure is not limited thereto. As described above, the comb-driven actuator 120 may be at least partially integrated into one or both of the stator 105 and the movable structure 110. A single (combined) drive circuit device presenting the functions described above may be used instead. Figure 1 The diagram shows two separate drive circuit devices 121 and 122.

[0024] Furthermore, the MEMS device 100 includes a sensor 130 configured to measure the motion of the movable structure 110 about a plurality of oscillating axes. The sensor 130 can be configured to measure changes in capacitance or other properties as the movable structure 110 moves. The sensor 130 allows for the capture of precise data on the motion dynamics around each oscillating axis, which is helpful in applications where precise control and sensing are important, such as in optical scanning or lidar systems.

[0025] For example, sensor 130 can be configured to measure the motion of movable structure 110 via the interlaced teeth (comb-actuated electrode structure) of the comb-driven actuator 120 described above for inducing motion of movable structure 110. In other words, in these examples, the teeth of comb-driven actuator 120 serve a dual purpose. They not only contribute to inducing motion via electrostatic force when an electric potential is applied, but also play a role in sensing that motion. When movable structure 110 oscillates, the relative displacement causes a change in capacitance between the interlaced teeth. Sensor 130 can be configured to measure (detect) these capacitance changes, which are proportional to the motion of movable structure 110 about the oscillation axis. Therefore, sensor 130 is able to provide accurate feedback on the motion of movable structure 110 in response to actuation of comb-driven actuator 120.

[0026] In an alternative example, sensor 130 can be configured to use a second set of comb teeth to measure the motion of movable structure 110, which is different (separate) from the comb teeth (comb-shaped actuation electrode structure) of the comb-shaped drive actuator 120 described above for causing the motion of movable structure 110. The second set of comb teeth is a comb-shaped sensing electrode structure and is interleaved with the comb teeth of movable structure 110 (i.e., the comb-shaped electrode structure of movable structure 110). Similar to the other comb teeth described above, the comb teeth of the second set are made of a conductive material. The second set of comb teeth can be configured to be adjacent to the comb teeth of comb-shaped drive actuator 120. For example, a first portion of the second set of comb teeth can be formed on stator 105 and interleaved with the first comb-shaped electrode structure of movable structure 110 to measure the motion of movable structure 110 about a first oscillation axis. The second portion of the second set of comb teeth can be formed on the first portion 113 of the movable structure 110 and interleaved with the second comb-shaped electrode structure of the movable structure 110 to measure the motion of the movable structure 110 about the second oscillation axis. Similar to the above description of motion sensing via the dual-purpose comb teeth of the comb-driven actuator 120, the second set of comb teeth allows for the measurement (detection) of capacitance changes between the interleaved comb teeth, which indicate the motion of the movable structure 110 about the oscillation axis. For example, capacitance is a nonlinear function of the rotation angle of the movable structure 110 about the oscillation axis.

[0027] Sensor 130 may include a first measurement circuit 131 configured to read the comb teeth used to measure the motion of the movable structure 110 about a first oscillating axis. Specifically, the first measurement circuit 131 may be configured to read capacitance changes measured by the comb teeth used to measure the motion of the movable structure 110 about the first oscillating axis. Similarly, sensor 130 may include a second measurement circuit 132 configured to read the comb teeth used to measure the motion of the movable structure 110 about a second oscillating axis. Specifically, the second measurement circuit 132 may be configured to read capacitance changes of the comb teeth used to measure the motion of the movable structure 110 about the second oscillating axis. The first measurement circuit 131 and the second measurement circuit 132 may be electrically coupled to the comb teeth used to measure the motion of the movable structure 110 about the oscillating axis via multiple conductive paths, traces, or channels. According to an example, the two measurement circuit devices 131 and 132 and the two drive circuit devices 121 and 122 may be integrated devices.

[0028] For the sake of brevity, Figure 1 The sensor 130 is schematically shown, and various details such as the aforementioned second set of comb teeth are not included. Figure 1 The image is shown in the middle. Figure 1In the example, sensor 130 is illustrated as an element separate from stator 105 and movable structure 110. However, this disclosure is not limited thereto. As indicated above, sensor 130 may be at least partially integrated into one or both of stator 105 and movable structure 110. Similarly—as Figure 1 As indicated, sensor 130 and comb-driven actuator 120 can be at least partially integrated. A single (combined) measurement circuit device presenting the above functions can be used instead of... Figure 1 The two measuring circuit devices 131 and 132 shown in the figure.

[0029] MEMS device 100 also includes control circuitry 140 configured to perform one or more of the following: a) During the measurement time window in which sensor 130 measures the motion of movable structure 110 about one of the oscillating axes, control comb-driven actuator 120 to maintain the corresponding drive voltage for the other oscillating axes at a constant level; and b) Discard the motion measured by sensor 130 for one of the oscillating axes in the sensing suppression time window, which is initiated by a switching event of the drive voltage of either of the oscillating axes.

[0030] The measurement time window is the period (duration) during which the sensor 130 measures the motion of the movable structure 110 about one of a plurality of oscillating axes. Due to the close proximity of the comb teeth, potentially insufficient isolation of the wiring (signal) lines between the sensor 130 / comb-driven actuator 120 and the comb teeth, and electromagnetic interference, electrical interference or crosstalk can occur between the comb teeth when the drive voltage changes during measurement, leading to ineffective sensing. By controlling the comb-driven actuator 120 to maintain a constant drive voltage for the non-measuring oscillating axis during the measurement time window, the control circuitry 140 can effectively reduce electrical interference or crosstalk, thereby improving the fidelity of the sensor measurement. In other words, switching suppression can be used so that the other (non-measuring) axes must maintain their drive voltages constant during measurement.

[0031] Alternatively or additionally, sensing suppression can be used such that motion measurements taken by sensor 130 for one of the oscillating axes within a sensing suppression time window are discarded. The sensing suppression time window is a period of time (duration) during which motion measurements are considered invalid because they are affected by a drive voltage switching event. In other words, if any axis performs a drive voltage switch that affects the corresponding measurement window, the motion measurement will be discarded. By discarding sensor measurements for one of the oscillating axes within the sensing suppression time window initiated by a drive voltage switching event, the control circuitry can prevent erroneous data collection due to transient disturbances caused by the switching event.

[0032] Active management of the control circuitry 140 can enhance the measurement accuracy and system stability of the MEMS device 100, making it well-suited for advanced technology applications where accuracy and consistency are critical.

[0033] The control circuit device 140 performs the control in Figure 2 An exemplary illustration is provided in the timing diagram 200. The time process of the oscillating motion of the movable structure 110 is illustrated by curve 201.

[0034] First, the switching suppression will be explained. Measurement time window 210 is scheduled from time t2 to time t4. Sensor 130 measures the motion of the movable structure 110 about one of the oscillating axes within measurement time window 210. Curve 205 indicates the operation of sensor 130. A high signal level on curve 205 indicates that sensor 130 is measuring motion about the oscillating axis. A low signal level on curve 205 indicates that sensor 130 is not measuring motion about the oscillating axis.

[0035] Since sensor 130 measures the motion of movable structure 110 about one of the oscillating axes within the measurement time window 210, control circuitry 140 is configured to control comb-driven actuator 120 to maintain the corresponding drive voltages for the other oscillating axes at a constant level. In other words, the other oscillating axes must maintain their drive voltages constant during measurement. This is in Figure 2 An exemplary illustration is provided for one oscillating axis. Curve 220 shows the initial predetermined time course of the drive voltage for this oscillating axis. At time t3 within the measurement time window 210, a switching event of the drive voltage is initially predetermined. The switching event is the point in time (moment) at which the drive voltage of one of the oscillating axes changes. The switching event includes a transition of the drive voltage from a first signal level to a different second signal level, causing movement of the movable structure 110 about the corresponding oscillating axis. The switching event may cause transient effects affecting the measurements performed by sensor 130. Therefore, control circuitry 140 can be configured to control comb-driven actuator 120 to shift the predetermined switching event to a time after the measurement time window 210. Curve 230 shows a modified time course of the drive voltage for the oscillating axis. As shown by curve 230, the switching event is shifted to time t4, at which time the measurement time window 210 ends, such that sensor measurements of movement about one oscillating axis performed within the measurement time window 210 are unaffected by the switching event of the other oscillating axis. In other words, the drive voltage is shifted out of the measurement time window 210. In other examples, the switching event may be omitted entirely. Therefore, the observability of this axis is guaranteed.

[0036] The control circuitry 140 can be configured to control the comb-driven actuator 120 to maintain the corresponding drive voltage for other oscillating axes at a constant level during a switching suppression time window 250, which extends before and includes the measurement time window 210. Any drive voltage switching event will cause distortion of the sensing signal for all oscillating axes, and therefore, motion measurements for oscillating axes should be avoided within the distortion time window 240 initiated by the switching event. For example, the switching event may last for about 100 ns and continue to cause distortion for a period of time (e.g., 1 μs) after the switching event: therefore, the duration of the switching event and the duration of distortion after the switching event define the distortion time window 240, during which the switching event should be avoided to ensure reliable sensor measurements of motion with respect to one oscillating axis during the measurement time window 210. Thus, for example, the switching suppression time window 250 can be defined as a combination of the distortion time window 240 and the measurement time window 210.

[0037] Figure 2 This further highlights the aforementioned sensing suppression. A switching event of the drive voltage for one of the oscillating axes occurs at time t1. Any drive voltage switching event will cause distortion of the sensing signal for all oscillating axes. The distortion persists for a certain time span after the switching event. Therefore, the distortion time window 240 can also be understood as a sensing suppression time window 240 initiated by the switching event at time t1. The sensing suppression time window 240 begins at time t1 and ends at time t2. If sensor 130 is to measure motion for one of the oscillating axes within the sensing suppression time window 240, control circuitry 140 will discard the measured motion. In other words, if any axis performs a drive voltage switching event affecting the corresponding measurement window, the measurement will be discarded. In the case that the measured motion is discarded, the error used to induce motion of the movable structure 110 via the comb-driven actuator 120 cannot be updated based on the measured motion. For example, the error can be set to zero, or an error estimate can be performed using an observer.

[0038] The duration of distortion after a switching event depends on various parameters. For example, the duration of distortion depends on how the comb-driven actuator 120 changes the drive voltage (i.e., whether the drive voltage is turned on / off or increased / decreased). Furthermore, the duration of distortion also depends on whether the drive voltage is switched by the comb-driven actuator 120 for the oscillating axis whose motion is being measured by the sensor 130, or for another oscillating axis. Therefore, the control circuitry 140 can be configured to set the length of the sensing suppression time window 240 based on how the comb-driven actuator 120 changes the drive voltage. Alternatively, the control circuitry 140 can be configured to set the length of the sensing suppression time window 240 based on whether the drive voltage is switched by the comb-driven actuator 120 for the oscillating axis whose motion is being measured by the sensor 130, or for another oscillating axis. For example, a predetermined value for the sensing suppression time can be selected from multiple predetermined values ​​based on one or more of the criteria described above.

[0039] According to the example, within a time window 250 given by the sensing suppression time window 240 plus the measurement window 210, it may be impossible for any oscillating axis to switch its drive voltage. This is further illustrated in curve 255. A high signal level on curve 255 indicates that the control circuitry 140 controls the comb drive actuator 120 to maintain the corresponding drive voltage for other oscillating axes at a constant level. A low signal level on curve 255 indicates that the comb drive actuator 120 can change the drive voltage for the oscillating axis.

[0040] As described above, the control circuitry 140 can use one or both of switching suppression and sensing suppression. Combining these two techniques allows consideration of sensing capability / observability (e.g., avoiding long periods of sensing suppression) and energy balance (e.g., avoiding long periods of switching suppression). Therefore, observability and energy balance can be optimized. While switching suppression guarantees observability for one oscillation axis, it may introduce drive voltage distortion into other oscillation axes, affecting their oscillation stability. The combination of switching suppression and sensing suppression allows these effects to be balanced.

[0041] For example, measurements of the oscillating axis can be guaranteed only for every nth measurement, or random selection can be used. In other words, the control circuitry 140 can be configured to control the comb-driven actuator 120 to maintain the corresponding drive voltage for other oscillating axes at a constant level only during every nth measurement time window or during a randomly selected time window, whereby the sensor 130 measures the motion of the movable structure 110 about one of the oscillating axes, and during a randomly selected time window, the sensor 130 measures the motion of the movable structure about one of the oscillating axes.

[0042] Alternatively, the control circuitry 140 can be configured to control the comb-driven actuator 120 to skip every m-th predetermined switching event of the drive voltage, or to skip a randomly selected subset of predetermined switching events of the drive voltage, for at least one of the oscillating axes. This is a less efficient but simpler method and allows for pre-programming of the distortion of the drive signal for the oscillating axis. The difference from the method described above is that the drive time period is skipped even if no measurements are affected.

[0043] According to the examples in this disclosure, the quality factor (Q factor) of the MEMS device 100 can be 1000 or higher. The Q factor determines how the MEMS device 100 handles pulse displacement and energy efficiency. In particular, a high Q factor allows for smoothing of the displacement or shift of switching events through the aforementioned switching suppression. This smoothing occurs because the energy dissipation in the MEMS device 100 is relatively small compared to the energy stored within the MEMS device 100. Due to this small energy loss, the oscillation amplitude experiences only minimal impact and remains at a constant level despite external or transient disturbances. A high Q factor greater than 1000 ensures that the MEMS device 100 can effectively maintain its oscillation, meaning that the energy input required to maintain performance is minimized. Therefore, the MEMS device 100 maintains its operational stability, accuracy, and precision.

[0044] MEMS device 100 can be used in a variety of applications. For example, a mirror 150 can be formed on the surface of movable structure 110 (e.g., the surface of the second portion 114 of movable structure 100). In other words, MEMS device 100 can be a MEMS mirror. Mirror 150 can be used to deflect light 161 (e.g., a beam or light pulse) emitted by light source 160 (e.g., a laser (diode)). Examples of this disclosure can provide suppression of electronic crosstalk from actuation to sensing in multi-axis MEMS mirrors. Figure 1 As indicated, the control circuitry 140 can also be configured to control the light emission time of the light source 160. For example, the control circuitry 140 can be configured to synchronize the light emission by the light source 160 with the oscillating motion of the movable structure 110 by controlling the light emission time of the light source 160. In this configuration, the MEMS device 100 can be used in various applications, such as laser beam scanning or lidar systems. The light source 160 can be part of the MEMS device 100 or can be separate from the MEMS device 100 (external to the MEMS device 100).

[0045] To further highlight the control of the aforementioned MEMS devices Figure 3A flowchart of method 300 for operating a MEMS device is illustrated. Method 300 includes using a comb-driven actuator of the MEMS device to induce motion of a movable structure of the MEMS device about a plurality of oscillating axes. Furthermore, method 300 includes using a sensor of the MEMS device to sense the motion of the movable structure about the plurality of oscillating axes. Method 300 further includes performing one or more of the following: a) while measuring the motion of the movable structure about one of the oscillating axes, controlling the comb-driven actuator to maintain the corresponding drive voltages for the other oscillating axes at constant levels; and b) discarding the motion of one of the oscillating axes measured by the sensor within a sensing suppression time window, the sensing suppression time window being initiated by a switching event of the drive voltage for any of the oscillating axes.

[0046] Similar to the description above, method 300 helps to improve the measurement accuracy and system stability of MEMS devices.

[0047] Further details and aspects of method 300 can be found in conjunction with the proposed techniques or one or more of the examples described above (e.g., Figure 1 and Figure 2 This is explained in [reference needed]. Method 300 may include one or more additional optional features corresponding to one or more aspects of the proposed technique or one or more of the examples above.

[0048] Examples may also be or relate to a (computer) program that includes program code for performing one or more of the methods described above when the program is executed on a computer, processor, or other programmable hardware component. Therefore, the steps, operations, or processes of the different methods described above can also be performed by a programmed computer, processor, or other programmable hardware component. Examples may also cover program storage devices, such as machine-readable, processor-readable, or computer-readable digital data storage media, which encode and / or contain machine-executable, processor-executable, or computer-executable programs and instructions. Program storage devices may include, or may be, for example, digital storage devices, magnetic storage media (e.g., disks and tapes), hard disk drives, or optically readable digital data storage media. Other examples may also include computers, processors, control units, (field-programmable arrays) ((F)PLAs), (field-programmable gate arrays) ((F)PGAs), graphics processing units (GPUs), ASICs, integrated circuits (ICs), or SoCs programmed to perform the steps of the methods described above.

[0049] Although specific examples have been illustrated and described herein, those skilled in the art will understand that various alternatives and / or equivalent embodiments can be used to replace the illustrated and described specific examples without departing from the scope of the invention. This application is intended to cover any modifications or variations of the specific examples discussed herein. Therefore, the invention is intended to be limited only by the claims and their equivalents.

[0050] It should be noted that the methods and devices (including their preferred embodiments) outlined in this document can be used alone or in combination with other methods and devices disclosed in this document. Furthermore, features outlined in the context of a device also apply to the corresponding method, and vice versa. Moreover, all aspects of the methods and devices outlined in this document can be combined arbitrarily. In particular, features in the claims can be combined with each other in any manner.

[0051] It should be noted that the specification and accompanying drawings only illustrate the principles of the proposed methods and systems. Those skilled in the art will be able to implement various arrangements, which, while not explicitly described or shown herein, embody the principles of the invention and are included within its spirit and scope. Furthermore, all examples and embodiments outlined in this document are primarily and explicitly intended for illustrative purposes only to aid the reader in understanding the principles of the proposed methods and systems. Moreover, all statements herein providing principles, aspects, and embodiments of the invention, as well as specific examples thereof, are intended to cover their equivalents.

Claims

1. A MEMS device (100), comprising: The movable structure (110) is configured to oscillate about multiple oscillation axes; The actuator (120) is configured to cause the movable structure (110) to move about the plurality of oscillating axes; A sensor (130) is configured to measure the motion of the movable structure (110) about the plurality of oscillating axes; as well as The control circuit device (140) is configured to perform one or more of the following: a) During the measurement time window, the actuator (120) is controlled to maintain the corresponding drive voltage for the other oscillating axes at a constant level, during which the sensor (130) measures the motion of the movable structure (110) about one of the oscillating axes; as well as b) Discard the motion measured by the sensor (130) for one of the oscillating axes in the sensing suppression time window, which is initiated by a switching event of the drive voltage for any of the oscillating axes.

2. The MEMS device (100) of claim 1, wherein the control circuitry (140) is configured to perform a), and wherein the control circuitry (140) is configured to control the actuator (120) to maintain the corresponding drive voltage for the other oscillation axis at the constant level during a switching suppression time window, the switching suppression time window extending before and including the measurement time window.

3. The MEMS device (100) according to claim 1 or 2, wherein the control circuitry (140) is configured to perform a), and wherein, If a switching event for the drive voltage of one of the other oscillating axes is scheduled to occur during the measurement time window or the switching suppression time window, the control circuit device (140) is configured to control the actuator (120) to shift the scheduled switching event to a time after the measurement time window or the switching suppression time window.

4. The MEMS device (100) according to any one of claims 1 to 3, wherein the control circuit device (140) is configured to perform b), and wherein the control circuit device (140) is configured to set the length of the sensing suppression time window based on the manner in which the actuator (120) changes the driving voltage.

5. The MEMS device (100) according to any one of claims 1 to 4, wherein the control circuit device (140) is configured to perform b), and wherein the control circuit device (140) is configured to set the length of the sensing suppression time window based on whether the driving voltage is switched by the actuator (120) for the oscillation axis whose motion is being measured by the sensor (130), or for another oscillation axis.

6. The MEMS device (100) according to any one of claims 1 to 5, wherein the control circuit device (140) is configured to perform a) and b), and wherein the control circuit device (140) is configured to control the actuator (120) to continuously maintain the corresponding drive voltage for the other oscillation axis at the constant level only in every nth measurement time window or only in a randomly selected time window, wherein in every nth measurement time window, the sensor (130) measures the motion of the movable structure (110) with respect to the one of the oscillation axes, and in the randomly selected time window, the sensor (130) measures the motion of the movable structure (110) with respect to the one of the oscillation axes.

7. The MEMS device (100) according to any one of claims 1 to 5, wherein the control circuit device (140) is configured to perform a) and b), and wherein the control circuit device (140) is configured to control the actuator (120) to skip every m-th predetermined switching event of the drive voltage for at least one of the oscillating shafts, or to skip a randomly selected subset of the predetermined switching events of the drive voltage.

8. The MEMS device (100) according to any one of claims 1 to 7, wherein the Q factor of the MEMS device (100) is 1000 or higher.

9. The MEMS device (100) according to any one of claims 1 to 8, wherein a mirror is formed on the surface of the movable structure (110).

10. The MEMS device (100) according to any one of claims 1 to 9, wherein the sensor (130) is configured to measure the motion of the movable structure (110) via interlaced comb teeth of the actuator (120) for causing the motion of the movable structure (110).

11. The MEMS device (100) according to any one of claims 1 to 9, wherein the sensor (130) is configured to measure the motion of the movable structure (110) using a second set of comb teeth different from the comb teeth of the actuator (120) used to cause the motion of the movable structure (110).

12. The MEMS device (100) according to claim 11, wherein the second set of comb teeth is configured adjacent to the comb teeth of the actuator (120).

13. The MEMS device (100) according to any one of claims 1 to 12, wherein the actuator (120) is a comb-driven actuator.

14. A method (300) for operating a MEMS device, the method comprising: The actuator of the MEMS device is used to cause (302) the movement of the movable structure of the MEMS device about a plurality of oscillation axes; The sensor of the MEMS device is used to sense (304) the motion of the movable structure about the plurality of oscillation axes; as well as Perform one or more of the following: When the motion of the movable structure about one of the oscillating axes is measured, the actuator (306) is controlled to maintain the corresponding drive voltage for the other oscillating axes at a constant level. as well as Discard (308) the motion measured by the sensor for one of the oscillating axes during the sensing suppression time window, which is initiated by a switching event of the drive voltage for any of the oscillating axes.

15. A non-transitory machine-readable medium having a program stored thereon, the program having program code for performing the method (300) according to claim 13 when the program is executed on a processor or programmable hardware.

16. A program having program code for performing the method (300) according to claim 13 when the program is executed on a processor or programmable hardware.

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