Micro-electro-mechanical system (MEMS) device and noise cancellation method

Abstract

A micro-electromechanical system (MEMS) device (102, 200, 300, 404) is provided for cancelling noise generated by oscillation of a movable micro-electromechanical system (MEMS) element (104, 204, 304, 406). The micro-electromechanical system (MEMS) device (102, 200, 300, 404) includes a movable micro-electromechanical system (MEMS) element (104, 204, 304, 406), an actuator (106, 208, 306, 408), a controller (108, 410), and a movable noise cancellation element (110, 202, 312, 412). The controller (108, 410) provides electrical signals to drive the actuator (106, 208, 306, 408) and the movable noise cancellation element (110, 202, 312, 412) to cancel noise generated in the micro-electromechanical system (MEMS) device (102, 200, 300, 404) by oscillation of the movable MEMS element (104, 204, 304, 406). The movable noise cancellation element (110, 202, 312, 412) generates anti-phase noise in accordance with the electrical signals received from the controller (108, 410) to cancel noise generated by oscillation of the movable MEMS element (104, 204, 304, 406) in accordance with the control signals received from the controller (108, 410).

Description

Technical Field

[0001] The present invention generally relates to micro-electromechanical system (MEMS) devices, and more particularly, to a noise cancellation method for micro-electromechanical system (MEMS) devices. Background Art

[0002] A micro-electromechanical system (MEMS) is a high-precision system used to sense, control, or drive at very small scales by combining mechanical, electrical, magnetic, thermal, and / or other physical phenomena. MEMS are used in biomedical applications, optical applications, acoustic applications, and the like. In some applications, MEMS are configured as movable components to provide high-precision results. For example, fast-moving parts of a MEMS, including optical elements such as MEMS galvanometers, are used to oscillate to controllably deflect light in optical applications, such as in projectors for virtual reality or augmented reality applications. The movement of a MEMS element can cause vibrations in the component or system containing the MEMS element, and this vibration can be disruptive to the user if the vibration is sensed by touch or if the vibration produces audible noise. MEMS component vibration is a particular problem in virtual reality or augmented reality devices, such as glasses, goggles, or helmets that contain one or more MEMS components. Because such devices are often worn on the head, vibrations and audible noise are more easily perceived by the wearer. However, it should be understood that even when MEMS components are part of a device that is not head-worn or body-worn, vibrations and noise caused by the movement of MEMS components can cause interference, so that even stand-alone devices may suffer from annoying vibrations or noise caused by the movement of MEMS components.

[0003] Existing technology vacuum encapsulates fast-moving MEMS elements to reduce the possibility of noise reaching the human ear located near fast-moving micro-electromechanical system (MEMS) components. However, this encapsulation requires an increase in the size of the packaged components and leads to an increase in weight, both of which have a negative impact on the user experience and also increase costs. In addition, even if vacuum-encapsulated movable MEMS elements can reduce the amount of audible noise generated, the vibrations caused by the movement of the MEMS elements can be mechanically coupled to parts or components that are not vacuum-encapsulated, which can also generate audible noise and may cause the user to perceive the mechanically coupled vibrations. The latter issue is particularly worthy of attention for head-mounted systems using movable MEMS elements.

[0004] Therefore, there is a need to address the above technical deficiencies in the prior art to improve the user experience of devices including micro-electromechanical system (MEMS) components. Summary of the Invention

[0005] It is an object of the present invention to mitigate the effects of vibrations generated in a micro-electromechanical system (MEMS) device while obviating one or more disadvantages of prior art approaches.

[0006] According to a first aspect, a micro-electromechanical system (MEMS) device is provided, comprising:

[0007] Movable MEMS components;

[0008] an actuator operable to move the movable MEMS element;

[0009] a controller for controlling the actuator to achieve controlled movement of the movable MEMS element;

[0010] The device further comprises:

[0011] A movable noise cancellation element is arranged to be driven under the control of the controller to generate anti-phase noise to cancel noise generated by oscillation of the movable MEMS element.

[0012] An advantage of this aspect is that the noise generated by the movement of the movable MEMS element can be eliminated, the impact of the noise can be reduced, and the user experience can be improved, especially when the MEMS device is a wearable device.

[0013] In a first possible implementation of the MEMS device of the first aspect, the movable MEMS element and the actuator are constructed on a common semiconductor substrate. This makes the coupling between them more efficient and achieves a very compact structure. In a second possible implementation of the MEMS device of the first aspect itself or the first possible implementation of the first aspect, the actuator and the movable MEMS element are encapsulated in a common sealed package, and the movable noise cancellation element is located outside the common sealed package. Any sealed package is preferably evacuated to form a near vacuum.

[0014] In a third possible implementation manner of the MEMS device of the first aspect, the movable MEMS element is a MEMS element of a MEMS structure, and the actuator is not an element of the MEMS structure providing the movable MEMS element.

[0015] In a fourth possible implementation of the MEMS device of the third possible implementation of the first aspect, the movable noise cancellation element and the actuator are mounted on a common substrate. Use of the common substrate enables the movable noise cancellation element to effectively cancel noise, and in particular, better cancel noise generated by movement of the actuator.

[0016] In a fifth possible implementation manner of the MEMS device of the fourth possible implementation manner of the first aspect, the movable MEMS element is mounted on the actuator. When the MEMS element is mounted on the actuator, the actuator controls the movement of the movable MEMS element.

[0017] In a sixth possible implementation of the MEMS device of the third possible implementation of the first aspect, the actuator is a piezoelectric element.

[0018] In a seventh possible implementation of the MEMS device of the first aspect itself or the first possible implementation or the second possible implementation of the first aspect, the movable noise cancellation element is a MEMS element.

[0019] In an eighth possible implementation manner of the MEMS device of the seventh possible implementation manner, when combined with the first possible implementation manner of the first aspect, the movable noise cancellation element is also constructed on the common semiconductor substrate. When constructed on the common semiconductor substrate, the movable noise cancellation element occupies less space in the MEMS device.

[0020] In a ninth possible implementation of the first aspect itself or the MEMS device according to any of the above implementations of the first aspect, the movable noise cancellation element is a piezoelectric element.

[0021] In a tenth possible implementation of the MEMS device of the ninth possible implementation, when combined with the sixth possible implementation of the first aspect, the controller is configured to feed the actuator and the movable noise cancellation element the same electrical signal, but 180 degrees out of phase. By using the same electrical signal 180 degrees out of phase, the processing burden of the controller can be reduced and the effectiveness of noise cancellation can be improved.

[0022] In an eleventh possible implementation of the MEMS device of the first aspect itself or according to any of the first to ninth above-mentioned implementations of the first aspect, the MEMS device is provided in combination with a transducer arranged to provide a signal derived from noise generated by the movable MEMS element to the controller.

[0023] In a twelfth possible implementation of the MEMS device of the eleventh possible implementation of the first aspect, the controller is configured to generate a signal to drive the movable noise cancellation element according to a signal received from the transducer.

[0024] In a thirteenth possible implementation of the first aspect itself or the MEMS device according to any of the above implementations of the first aspect, the movable MEMS element is an optical element.

[0025] In a fourteenth possible implementation of the MEMS device of the thirteenth possible implementation of the first aspect, the MEMS device is provided in combination with an acoustic enclosure surrounding the MEMS device, the acoustic enclosure defining a hole through which light can pass from the movable optical MEMS element.

[0026] In a fifteenth possible implementation of the MEMS device of the fourteenth possible implementation of the first aspect, the arrangement is such that noise from the movable optical MEMS element and anti-phase noise from the movable noise elimination element can be transmitted out of the sound insulation enclosure through the hole to achieve noise elimination in the direction of light passing through the hole from the movable optical MEMS element.

[0027] In a sixteenth possible implementation of the first aspect itself or the MEMS device according to any of the above implementations of the first aspect, the movable noise cancellation element and the controller are further configured to generate anti-phase noise to cancel noise generated by movement of the actuator.

[0028] According to a second aspect, a wearable device is provided, characterized in that it comprises one or more MEMS devices according to the first aspect or any possible implementation thereof.

[0029] In a first possible implementation of the wearable device of the second aspect, the wearable device is used for a virtual reality (VR) or augmented reality (AR) display. The wearable device optionally includes at least one of glasses, headphones, a helmet, a watch, a smartphone, or a tablet. One or more MEMS devices in the augmented reality or virtual reality display improve the user experience when using the AR / VR display.

[0030] According to a third aspect, there is provided a noise cancellation method for a micro-electromechanical system (MEMS) device, the method comprising:

[0031] generating noise by applying a signal to an actuator of the MEMS device to cause controlled movement of a movable MEMS element of the MEMS device;

[0032] A noise cancellation signal is applied to a movable noise cancellation element of the MEMS device to generate anti-phase noise to cancel noise generated by oscillation of the movable MEMS element.

[0033] This method can cancel noise generated in micro-electromechanical system (MEMS) devices by generating anti-phase noise. The method helps improve the user experience by effectively canceling the noise generated by movable MEMS elements.

[0034] In a first possible implementation of the third aspect, the signal applied to the actuator is the same as the noise cancellation signal applied to the movable noise cancellation element, but is 180 degrees out of phase.

[0035] In a second possible implementation manner of the third aspect, the method includes:

[0036] using a transducer to generate an electrical signal based on noise generated by movement of the movable MEMS element;

[0037] The electrical signal generated by the transducer is processed to generate a noise cancellation signal that is applied to the noise cancellation element. The transducer can convert the electrical signal into mechanical displacement or stress based on the piezoelectric effect.

[0038] According to a fourth aspect, there is provided a method of manufacturing a micro-electromechanical system (MEMS) device including a noise cancellation function, the method comprising:

[0039] Building movable MEMS components;

[0040] constructing a MEMS actuator operable to move the movable MEMS element;

[0041] A movable noise cancellation MEMS element is constructed that can be driven to generate anti-phase noise to cancel the noise generated by the oscillation of the movable MEMS element; wherein the three construction operations are performed on the same semiconductor substrate.

[0042] This method enables the construction of compact MEMS devices that provide good noise cancellation performance. The MEMS device manufactured by the method of the fourth aspect can be built into a compact assembly that has good noise cancellation performance, making it particularly suitable for applications such as AR / VR.

[0043] According to a fifth aspect, there is provided a method of manufacturing a micro-electromechanical system (MEMS) device including a noise cancellation function, the method comprising:

[0044] coupling the movable MEMS element to an external actuator operable to move the movable MEMS element;

[0045] bonding the external actuator to a substrate;

[0046] A movable noise cancellation element is bonded to the substrate, the movable noise cancellation element being drivable to generate anti-phase noise to cancel noise generated by oscillation of the movable optical MEMS element.

[0047] The MEMS device made by the method of the fifth aspect can be built into a compact component with good noise cancellation performance, making it particularly suitable for applications such as AR / VR.

[0048] In a first possible implementation manner of the fifth aspect, the substrate is used to mechanically decouple the external actuator from the movable noise cancellation element.

[0049] These and other aspects of the invention are apparent from one or more embodiments described in the following figures and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] An embodiment of the present invention will now be described by way of example only with reference to the following figures, in which:

[0051] Figure 1 is a schematic diagram of a micro-electromechanical system (MEMS) device with noise cancellation function according to an embodiment of the present invention;

[0052] Figure 2is a schematic diagram of a micro-electromechanical system (MEMS) device having a noise cancellation element according to an embodiment of the present invention;

[0053] Figure 3 is a schematic diagram of noise (air oscillation) elimination in a micro-electromechanical system (MEMS) device according to an embodiment of the present invention;

[0054] Figure 4 is a schematic diagram of an example wearable device having a micro-electromechanical system (MEMS) device for canceling noise generated by oscillation of a movable micro-electromechanical system (MEMS) element according to an embodiment of the present invention;

[0055] Figure 5 is a flow chart of a method for eliminating noise in a micro-electromechanical system (MEMS) device according to an embodiment of the present invention;

[0056] Figure 6 is a flow chart of an exemplary method for manufacturing a micro-electromechanical system (MEMS) device with noise cancellation functionality according to an embodiment of the present invention;

[0057] Figure 7 is a flow chart of an exemplary method for fabricating a micro-electromechanical system (MEMS) device with noise cancellation functionality according to an embodiment of the present invention.

[0058] Specific implementation method

[0059] Embodiments of the present invention provide a micro-electromechanical system (MEMS), device, and method to mitigate the effects of vibrations generated in a micro-electromechanical system (MEMS) device, thereby improving user experience.

[0060] To make the solutions of the present invention easier for those skilled in the art to understand, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. The described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making any creative efforts shall fall within the scope of protection of the present invention.

[0061] In order to help understand the embodiments of the present invention, several terms that will be introduced in the description of the embodiments of the present invention are first defined herein.

[0062] The terms "first," "second," "third," and "fourth" (if any) in the specification, claims, and drawings of the present invention are used to distinguish similar objects and are not necessarily used to describe a particular sequence or order. It should be understood that the terms so used are interchangeable where appropriate, for example, so that the embodiments of the invention described herein can be implemented in sequences other than those shown or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not necessarily limited to the steps or units explicitly listed, but may include other steps or units that are not explicitly listed or that are inherent to such process, method, product, or apparatus.

[0063] Figure 1 FIG1 is a schematic diagram of a micro-electromechanical system (MEMS) device 102 having noise cancellation functionality according to an embodiment of the present invention; the micro-electromechanical system (MEMS) device 102 includes a movable MEMS element 104, an actuator 106, a controller 108, and a movable noise cancellation element 110. The actuator 106 is operable to move the movable MEMS element 104. The controller 108 controls the actuator 106 to cause controlled movement of the movable MEMS element 104. The movable noise cancellation element 110 is arranged to be driven under the control of the controller 108 to generate anti-phase noise, thereby canceling the noise generated by the oscillation of the movable MEMS element 104.

[0064] The movable MEMS element 104 is connected to an actuator 106. A controller 108 provides electrical signals to the actuator 106 for controlling the movement of the movable MEMS element 104. The actuator 106 converts the electrical signals into motion and moves the movable MEMS element 104 according to the electrical signals received from the controller 108. The actuator 106 can act as a transducer to convert electrical energy into mechanical displacement or stress based on the piezoelectric effect. A movable noise cancellation element 110 is optionally connected to the actuator 106. The controller 108 may optionally include a microcontroller (MCU), a microprocessor, or a digital signal processor (DSP).

[0065] The frequency of the noise generated by the movable MEMS element 104 (eg, a MEMS galvanometer) may be equal to the driving / operating frequency of the movable MEMS element 104 and may also be equal to the eigenfrequency of the MEMS assembly. The MEMS assembly may include the actuator 106 and / or the movable noise cancellation element 110.

[0066] Those skilled in the art will understand that the frequency of the noise to be eliminated is not within a wide frequency range of 20 Hz to 20,000 Hz (the typical maximum frequency range of human hearing), but within one or two specific frequencies, and the frequencies can be predicted based on the design of the MEMS component.

[0067] According to a first embodiment, movable MEMS element 104 and actuator 106 are built on a common semiconductor substrate. Movable MEMS element 104 and actuator 106 are optionally co-packaged in a common sealed package, and movable noise cancellation element 110 may be located outside the common sealed package.

[0068] According to the second embodiment, the movable MEMS element 104 is a MEMS element of a MEMS structure and the actuator 106 is not an element of the MEMS structure providing the movable MEMS element 104 .

[0069] The movable noise cancellation element 110 and the actuator 106 are optionally mounted on a common substrate when the actuator 106 is not an element of the MEMS structure that provides the movable MEMS element 104. When the movable noise cancellation element 110 and the actuator 106 are mounted on a common substrate, the movable MEMS element 104 is optionally mounted on the actuator 106. The actuator 106 is optionally a piezoelectric element.

[0070] The movable noise cancellation element 110 is optionally a MEMS element. When the movable MEMS element 104 and the actuator 106 are built on a common semiconductor substrate, and the movable noise cancellation element 110 is a MEMS element, the movable noise cancellation element 110 can be built on the common semiconductor substrate. The movable noise cancellation element 110 is optionally a piezoelectric element.

[0071] According to a third embodiment, when the actuator 106 is a piezoelectric element, the controller 108 is configured to feed the same electrical signal to the actuator 106 and the movable noise cancellation element 110, but 180 degrees out of phase. The controller 108 provides the electrical signal to the movable noise cancellation element 110 to produce noise cancellation vibrations. Typically, this involves providing a signal that is 180 degrees out of phase from the control signal provided to the actuator 106.

[0072] The micro-electromechanical system (MEMS) device 102 is optionally provided in combination with a transducer arranged to provide a signal derived from the noise produced by the movable MEMS element 104 to the controller 108. The controller 108 can be configured to generate a signal to drive the movable noise cancellation element 110 in dependence on the signal received from the transducer.

[0073] According to a fourth embodiment, the movable MEMS element 104 is optionally an optical element. When the movable MEMS element 104 is an optical element, the micro- electromechanical system (MEMS) device 102 is optionally used in combination with a soundproof enclosure that surrounds the MEMS device 102. The soundproof enclosure defines an aperture through which light can pass from the movable optical MEMS element. This arrangement enables the noise from the movable optical MEMS element and the anti-phase noise from the movable noise cancellation element 110 to be transmitted out of the soundproof enclosure through the aperture to achieve noise cancellation in the direction of light passing from the movable optical MEMS element through the aperture, thereby providing effective noise cancellation.

[0074] According to a fifth embodiment, the movable noise cancellation element 110 and the controller 108 are further configured to produce anti-phase noise to cancel noise produced by movement of the actuator 106.

[0075] The movable MEMS element 104 can comprise at least one of a galvanometer, a grating, a prism, or a light source. The movable MEMS element 104 can be a lens, a prism, a grating, a galvanometer, a light emitting diode, a modulator, or a photodetector, either as a whole or as a separate element. The movable MEMS element 104 is optionally placed in proximity to the actuator 106.

[0076] Figure 22 is a schematic diagram of a micro-electromechanical system (MEMS) device 200 having a movable noise cancellation element 202, according to an embodiment of the present invention. The micro-electromechanical system (MEMS) device 200 is shown unpackaged and may or may not be provided with a sealed package. The micro-electromechanical system (MEMS) device 200 includes a movable MEMS element 204, an actuator 208, a controller, and the movable noise cancellation element 202. The actuator 208 is operable to move the movable MEMS element 204. The controller controls the actuator 208 to cause controlled movement of the movable MEMS element 204. The movable noise cancellation element 202 is arranged to be driven under the control of the controller to generate anti-phase noise, thereby canceling noise generated by oscillation of the movable MEMS element 204.

[0077] The movable MEMS element 204 may include a micromirror chip positioned near an actuator 208 using a distance keeper 206. The actuator 208 may include a mirror actuation device (MAD), which may be a piezoelectric device. The actuator 208 receives an electrical signal from at least one of the controller or power supplies (V1 and V2) controlled by the controller. The controller may include a microcontroller (MCU), a microprocessor, or a digital signal processor (DSP).

[0078] The actuator 208 is operable to control the movement of the movable MEMS element 204. The movable MEMS element 204 may optionally include an optical element. The optical element may include at least one of a galvanometer, a grating, a prism, or a light source. The optical element may be a lens, a prism, a grating, a galvanometer, a light-emitting diode, a modulator, or a photodetector, either as a whole or as a separate element. The optical element (e.g., a galvanometer) is typically placed near the actuator 208. The movable MEMS element 204, the actuator 208, and the movable noise cancellation element 202 may optionally be constructed on a common semiconductor substrate 210.

[0079] Movable noise cancellation element 202 can be externally connected to micro-electromechanical system (MEMS) device 200 using mechanical coupling 212. Actuator 208 is initially coupled to movable MEMS element 204 and then optionally coupled to movable noise cancellation element 202. Movable noise cancellation element 202 and actuator 208 address the same periodic electrical signal with opposite phase differences. Movable noise cancellation element 202 can be set to a specific vibration amplitude to cancel noise generated in the unpackaged micro-electromechanical system (MEMS) device 200.

[0080] Movable noise cancellation element 202 can receive an electrical signal 180 degrees out of phase from at least one of the controller or power sources (V1 and V2) controlled by the controller. For example, actuator 208 receives electrical signal (V1) and movable noise cancellation element 202 receives electrical signal (V2), where V1 = V0 (sinθ) and V2 = V0 (sinθ + 180°). Electrical signals (V1) and (V2) can cause actuator 208 and movable noise cancellation element 202 to vibrate with a specific amplitude and periodicity, thereby canceling noise generated in micro-electromechanical system (MEMS) device 200.

[0081] Figure 3 FIG2 is a schematic diagram illustrating noise (air oscillation) cancellation of a micro-electromechanical system (MEMS) device 300 according to an embodiment of the present invention. The micro-electromechanical system (MEMS) device 300 includes a movable MEMS element 304, an actuator 306, a controller, and a movable noise cancellation element 312. The actuator 306 is operable to move the movable MEMS element 304. The controller controls the actuator 306 to cause controlled movement of the movable MEMS element 304. The movable noise cancellation element 312 is arranged to be driven under the control of the controller to generate anti-phase noise, thereby canceling the noise generated by the oscillation of the movable MEMS element 304.

[0082] The movable MEMS element 304 may include a micromirror chip placed near an actuator 306 using a distance keeper 302. The actuator 306 may include a mirror actuation device (MAD), and the MAD may be a piezoelectric device. The actuator 306 receives an electrical signal from at least one of the controller or a power supply controlled by the controller. The controller, movable MEMS element 304, actuator 306, and movable noise cancellation element 312 are shown here as being constructed on a common semiconductor substrate 308, but this structure is optional. The movable noise cancellation element 312 is optionally mechanically decoupled from the micro-electromechanical system (MEMS) device 300 by a mechanical decoupling device 310.

[0083] The movable noise cancellation element 312 can receive an electrical signal 180 degrees out of phase from at least one of the controller or a power source controlled by the controller. For example, the actuator 306 receives an electrical signal (V1) and the movable noise cancellation element 312 receives an electrical signal (V2), where V1 = V0 (sinθ) and V2 = V0 (sinθ + 180°). The electrical signals (V1) and (V2) cause the actuator 306 to move the movable MEMS element 304 to generate a noise wave 314, and cause the movable noise cancellation element 312 to generate an anti-phase noise 316. The noise wave 314 and the anti-phase noise 316 cancel each other at an annihilation region 318. The anti-phase noise generated by the movable noise cancellation element 312 is used to cancel noise generated in the micro-electromechanical system (MEMS) device 300.

[0084] The movable MEMS element 304 can be packaged using wafer-level packaging (WLP) technology. WLP technology optionally provides a sealed vacuum with wafer-level packaging. The movable MEMS element 304 optionally includes an optical element that generates noise in the micro-electromechanical system (MEMS) device 300. The optical element optionally includes a scanning mirror or a piezoelectric element (PE). The movable noise cancellation element 312 oscillates to generate anti-phase noise to cancel the noise generated by the micro-electromechanical system (MEMS) device 300. The movable noise cancellation element 312 adjusts the amplitude, frequency, and phase as needed to generate anti-phase noise, thereby canceling the noise from the movable MEMS element. A noise detection element, such as a microphone, is used to detect the noise generated in the micro-electromechanical system (MEMS) device 300. The noise detection element provides information to the controller, such as the movable noise cancellation element 312, which drives the noise cancellation element (e.g., MEMS element).

[0085] Figure 4 4 is a schematic diagram of an example wearable device 402 having a micro-electromechanical system (MEMS) device 404 for canceling noise generated by oscillation of a movable MEMS element 406, according to an embodiment of the present invention. Wearable device 402 having micro-electromechanical system (MEMS) device 404 includes movable MEMS element 406, actuator 408, controller 410, and movable noise cancellation element 412. Movable MEMS element 406 is coupled to actuator 408. Controller 410 provides an electrical signal to actuator 408 for controlling movement of movable MEMS element 406. Movable noise cancellation element 412 is connected to controller 410. Controller 410 generates an electrical signal that is 180 degrees out of phase with the electrical signal provided to actuator 408. The electrical signal provided by the controller 410 to the movable noise cancellation element 412 causes the movable noise cancellation element 412 to generate anti-phase noise to cancel the noise generated by the oscillation of the movable MEMS element 406 .

[0086] Figure 51 is a flow chart of a method for eliminating noise from a micro-electromechanical system (MEMS) device according to an embodiment of the present invention. In step 502, noise is generated from a movable MEMS element of the MEMS device by applying a signal to an actuator of the MEMS device to cause controlled movement of the movable MEMS element. In step 504, noise generated by the oscillation of the movable MEMS element is eliminated by applying a noise cancellation signal to the movable noise cancellation element of the MEMS device to generate anti-phase noise. The signal applied to the actuator is optionally the same as the noise cancellation signal applied to the movable noise cancellation element, but 180 degrees out of phase. The noise cancellation signal is optionally generated by processing an electrical signal generated based on the noise generated by the movement of the movable MEMS element using a transducer. The movable noise cancellation element can be manufactured in parallel with the micro-electromechanical system (MEMS) device. The movable noise cancellation element can optionally be manufactured externally relative to the actuator.

[0087] Figure 6 6 is a flow chart of an exemplary method for manufacturing a micro-electromechanical system (MEMS) device with noise cancellation functionality according to an embodiment of the present invention. In step 602, a movable MEMS element is constructed. In step 604, a MEMS actuator is constructed, the actuator being operable to move the movable MEMS element. In step 606, a movable noise cancellation MEMS element is constructed. The movable noise cancellation MEMS element is driven to generate anti-phase noise to cancel noise generated by oscillation of the movable MEMS element. These three construction operations are performed on the same semiconductor substrate.

[0088] Figure 7 7 is a flow chart of an exemplary method for manufacturing a micro-electromechanical system (MEMS) device with noise cancellation functionality according to an embodiment of the present invention. In step 702, a movable MEMS element is coupled to an external actuator that is operable to move the movable MEMS element. In step 704, the external actuator is bonded to a substrate. The substrate can be used to mechanically decouple the external actuator from the movable noise cancellation element. In step 706, the movable noise cancellation element is bonded to the substrate. The movable noise cancellation element is driven to generate anti-phase noise to cancel noise generated by oscillation of the movable optical MEMS element.

[0089] A micro-electromechanical system (MEMS) device according to the present invention is optionally implemented in at least one of a virtual reality or augmented reality application, but the MEMS device may alternatively form part of, for example, a micro-projector, a mobile phone, or a camera. The MEMS device is optionally used in applications where sound or vibration of a MEMS component (e.g., a movable MEMS element or actuator) may cause interference, particularly applications where the MEMS component is incorporated into a head-mounted component, such as in AR / VR glasses, AR / VR helmets, or similar devices. The MEMS device reduces interference caused by noise and vibration from the moving MEMS element. While this is of particular interest in body-worn and head-mounted devices such as augmented reality / virtual reality (AR / VR) applications, it is also beneficial in stand-alone devices. Micro-electromechanical system (MEMS) devices can reduce fatigue and increase user efficiency, as it is well known that environmental or background noise can adversely affect the ability to concentrate and perform at a high level. Micro-electromechanical system (MEMS) devices are optionally used in construction areas (such as aircraft maintenance or auto repair). Micro-electromechanical system (MEMS) devices are optionally used in medical applications, such as supporting doctors or surgeons when performing surgery or physical examinations. Micro-electromechanical system (MEMS) devices are optionally used in automotive laser scanner applications, such as lidar, heads-up displays (HUD), headlights, etc. Micro-electromechanical system (MEMS) devices are optionally used in smartphones, projectors, or cameras (3D or other).

[0090] The present invention solves a technical problem in the prior art, namely improving the user experience of devices with micro-electromechanical systems (MEMS) fast-moving parts.

[0091] Therefore, compared with the prior art, the present application provides a micro-electromechanical system (MEMS) device and a noise elimination method to reduce the negative effects of vibrations caused by the movement of MEMS elements. The micro-electromechanical system (MEMS) device according to the present application helps to improve the user experience by well eliminating the noise generated by the movable MEMS elements.

[0092] Although the present application and its advantages have been described in detail, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the application as defined by the appended claims.

Claims

1. A micro-electromechanical system (MEMS) device (102, 200, 300, 404), characterized in that: include: movable MEMS elements (104, 204, 304, 406); an actuator (106, 208, 306, 408) operable to move the movable MEMS element (104, 204, 304, 406); a controller (108, 410) for controlling the actuator (106, 208, 306, 408) to cause controlled movement of the movable MEMS element (104, 204, 304, 406); The device (102, 200, 300, 404) further includes: a movable noise cancellation element (110, 202, 312, 412) arranged to be driven under the control of the controller (108, 410) to generate anti-phase noise to cancel noise generated by oscillation of the movable MEMS element (104, 204, 304, 406); The movable noise cancellation element (110, 202, 312, 412) is a piezoelectric element.

2. The micro-electromechanical system device (102, 200, 300, 404) according to claim 1, characterized in that The movable MEMS element (104, 204, 304, 406) and the actuator (106, 208, 306, 408) are built on a common semiconductor substrate (210, 308).

3. The micro-electromechanical system device (102, 200, 300, 404) according to claim 1, characterized in that The actuator (106, 208, 306, 408) and the movable MEMS element (104, 204, 304, 406) are packaged together in a common sealed package, and the movable noise cancellation element (110, 202, 312, 412) is located outside the common sealed package.

4. The micro-electromechanical system device (102, 200, 300, 404) according to claim 1, characterized in that The movable MEMS element (104, 204, 304, 406) is a MEMS element of a MEMS structure, and the actuator (106, 208, 306, 408) is not an element of the MEMS structure providing the movable MEMS element (104, 204, 304, 406).

5. The micro-electromechanical system device (102, 200, 300, 404) according to claim 4, characterized in that The movable noise cancellation element (110, 202, 312, 412) and the actuator (106, 208, 306, 408) are mounted on a common substrate.

6. The micro-electromechanical system device (102, 200, 300, 404) according to claim 5, characterized in that The movable MEMS element (104, 204, 304, 406) is mounted on the actuator (106, 208, 306, 408).

7. The micro-electromechanical system device (102, 200, 300, 404) according to claim 4, characterized in that The actuator (106, 208, 306, 408) is a piezoelectric element.

8. The micro-electromechanical system device (102, 200, 300, 404) according to claim 1, characterized in that The movable noise cancellation element (110, 202, 312, 412) is a MEMS element.

9. The micro-electromechanical system device (102, 200, 300, 404) according to claim 2, characterized in that The movable noise cancellation element (110, 202, 312, 412) is a MEMS element that is also built on the common semiconductor substrate.

10. The micro-electromechanical system device (102, 200, 300, 404) according to claim 1, characterized in that The actuator (106, 208, 306, 408) is a piezoelectric element and the controller (108, 410) is used to feed the same electrical signal to the actuator (106, 208, 306, 408) and the movable noise cancellation element (110, 202, 312, 412), but 180 degrees out of phase.

11. The micro-electromechanical system device (102, 200, 300, 404) according to claim 1, characterized in that The micro-electromechanical system device is combined with a transducer to be arranged to provide a signal to the controller (108, 410) derived from noise generated by the movable MEMS element (104, 204, 304, 406).

12. The micro-electromechanical system device (102, 200, 300, 404) according to claim 11, characterized in that The controller (108, 410) is configured to generate a signal to drive the movable noise cancellation element (110, 202, 312, 412) based on a signal received from the transducer.

13. The micro-electromechanical system device (102, 200, 300, 404) according to claim 1, characterized in that The movable MEMS element (104, 204, 304, 406) is an optical element.

14. The micro-electromechanical system device (102, 200, 300, 404) according to claim 13, characterized in that The MEMS device is combined with an acoustic enclosure surrounding the MEMS device (102, 200, 300, 404), the acoustic enclosure defining an aperture through which light can pass from the movable MEMS element.

15. The micro-electromechanical system device (102, 200, 300, 404) according to claim 14, characterized in that The arrangement allows noise from the movable MEMS element and anti-phase noise from the movable noise cancellation element (110, 202, 312, 412) to pass out of the acoustic enclosure through the aperture to achieve noise cancellation in the direction of light from the movable MEMS element through the aperture.

16. The micro-electromechanical system device (102, 200, 300, 404) according to any one of the preceding claims, characterized in that The movable noise cancellation element (110, 202, 312, 412) and the controller (108, 410) are also used to generate anti-phase noise to cancel noise generated by movement of the actuator (106, 208, 306, 408).

17. A wearable device (402), characterized in that Comprising one or more of the micro-electromechanical systems devices (102, 200, 300, 404) according to any one of claims 1 to 16.

18. The wearable device (402) according to claim 17, characterized in that Used for Virtual Reality (VR) or Augmented Reality (AR) displays.

19. A noise cancellation method for a micro-electromechanical system (MEMS) device (102, 200, 300, 404), characterized in that: The method comprises: generating noise by applying a signal to an actuator (106, 208, 306, 408) of the micro-electro-mechanical systems device (102, 200, 300, 404) to cause controlled movement of a movable MEMS element (104, 204, 304, 406) of the micro-electro-mechanical systems device (102, 200, 300, 404); applying a noise cancellation signal to a movable noise cancellation element (110, 202, 312, 412) of the microelectromechanical system device (102, 200, 300, 404) to generate anti-phase noise to cancel noise generated by oscillation of the movable MEMS element (104, 204, 304, 406); The movable noise cancellation element (110, 202, 312, 412) is a piezoelectric element.

20. The method according to claim 19, characterized in that The signal applied to the actuator (106, 208, 306, 408) is the same as the noise cancellation signal applied to the movable noise cancellation element (110, 202, 312, 412), but is 180 degrees out of phase.

21. The method according to claim 19, wherein The method further comprises: using a transducer to generate an electrical signal based on noise generated by movement of the movable MEMS element (104, 204, 304, 406); The electrical signal generated by the transducer is processed to generate a noise cancellation signal that is applied to the movable noise cancellation element (110, 202, 312, 412).

22. A method of manufacturing a micro-electromechanical system (MEMS) device (102, 200, 300, 404) including a noise cancellation function, characterized in that: The method comprises: constructing a movable MEMS element (104, 204, 304, 406); constructing a MEMS actuator operable to move the movable MEMS element (104, 204, 304, 406); Constructing a movable noise cancellation element that can be driven to generate anti-phase noise to cancel the noise generated by the oscillation of the movable MEMS element (104, 204, 304, 406); wherein the three construction operations are performed on the same semiconductor substrate; The movable noise cancellation element (110, 202, 312, 412) is a piezoelectric element.

23. A method of manufacturing a micro-electromechanical system (MEMS) device (102, 200, 300, 404) including a noise cancellation function, characterized in that: The method comprises: coupling a movable MEMS element (104, 204, 304, 406) to an external actuator operable to move the movable MEMS element (104, 204, 304, 406); bonding the external actuator to a substrate; bonding a movable noise cancellation element (110, 202, 312, 412) to a substrate, the movable noise cancellation element (110, 202, 312, 412) being drivable to generate anti-phase noise to cancel noise generated by oscillation of the movable MEMS element; The movable noise cancellation element (110, 202, 312, 412) is a piezoelectric element.

24. The method according to claim 23, wherein The substrate is used to mechanically decouple the external actuator from the movable noise cancellation element (110, 202, 312, 412).

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