Bending actuator and panel audio speaker including the same

Abstract

The present application discloses a bending actuator and a panel audio speaker including the bending actuator. A distributed mode speaker (DML) includes a flat panel extending in a panel plane. The DML also includes a rigid slender member that is displaced from the flat panel and extends parallel to the panel plane, the slender member being mechanically coupled to the flat panel at a first position along the slender member and extending away from the first position to an end of the member that is free to vibrate in a direction perpendicular to the plane. The slender member includes a soft magnetic material. The DML also includes an electromagnetic system that includes at least one conductive coil having an axis perpendicular to the panel plane and displaced from the slender member. The DML also includes an electronic control module that is electrically coupled to the electromagnetic system and is programmed to fully energize the conductive coil so that the magnetic field generated by the conductive coil displaces the free end of the slender member.

Description

[0001] Description of the case

[0002] This application is a divisional application of Chinese invention patent application No. 201980088463.9, filed on November 13, 2019. Technical Field

[0003] The present disclosure relates to a bending actuator and a panel audio speaker including the bending actuator. Background Art

[0004] Many conventional speakers produce sound by inducing piston-like motion in a diaphragm. In contrast, panel audio speakers such as distributed mode speakers (DML) operate by inducing uniformly distributed vibration modes in the panel via electroacoustic actuators. Typically, the actuators are electromagnetic actuators or piezoelectric actuators.

[0005] Conventional piezoelectric actuators typically include toxic materials such as lead, while conventional EM actuators may include pre-magnetized materials such as iron or neodymium, which may be heavy, brittle, and / or difficult to manufacture. Furthermore, the pre-magnetized material may become inoperable when heated above its Curie temperature, thus causing the conventional piezoelectric actuator including the pre-magnetized material to cease operation. Summary of the invention

[0006] An actuator is disclosed that includes a rigid elongated member (e.g., a beam or plate) of soft magnetic material that exhibits a bending mode in response to actuation of one or more electromagnets positioned proximate to but displaced from the member. In some embodiments, the elongated member is attached to a panel by a short post and has a free end capable of vibrating. The electromagnet pair is positioned on opposite sides of the member, and when the electromagnets are activated, they generate a magnetic field that causes the member to bend. In the absence of a magnetic field, the restoring force generated by the deflection of the member returns the member to its resting state. By appropriately circulating current through the relative electromagnets, various vibration modes can be activated in the member, and these vibrations are transmitted to the plate via the short post.

[0007] In general, in a first aspect, the present invention features a distributed mode loudspeaker comprising a flat panel extending in a panel plane. The distributed mode loudspeaker further comprises a rigid elongated member displaced from the flat panel and extending parallel to the panel plane, the elongated member being mechanically coupled to the flat panel at a first position along the elongated member and extending away from the first position to an end of the member that is free to vibrate in a direction perpendicular to the plane. The elongated member comprises a soft magnetic material. The distributed mode loudspeaker further comprises an electromagnetic system comprising at least one conductive coil having an axis perpendicular to the panel plane and displaced from the elongated member. The distributed mode loudspeaker further comprises an electronic control module electrically coupled to the electromagnetic system and programmed to sufficiently energize the conductive coil so that the magnetic field generated by the conductive coil displaces the free end of the elongated member perpendicular to the panel plane.

[0008] Implementations of the distributed mode loudspeaker may include one or more of the following features and / or one or more features of other aspects. For example, the electronic control module may be programmed to energize the conductive coil to vibrate the elongated member at a frequency and amplitude sufficient to produce an audio response from the panel.

[0009] In some embodiments, the conductive coil is a first conductive coil, and the electromagnetic system further comprises a second conductive coil having a corresponding axis perpendicular to the plane of the panel, the first conductive coil and the second conductive coil being on opposite sides of the elongated member. The first conductive coil and the second conductive coil may be aligned along a common axis. The electronic control module may be programmed to energize the first conductive coil and the second conductive coil simultaneously to cause the elongated member to vibrate.

[0010] In some embodiments, the member is mechanically coupled to the plate by a rigid element that displaces the member from the surface of the plate.

[0011] In other embodiments, the distributed mode loudspeaker further comprises a rigid frame, and the conductive coil is mechanically coupled to the rigid frame. The rigid frame can mechanically ground the conductive coil.

[0012] In some embodiments, the conductive coil is disposed between the plate and the elongated member. In other embodiments, the elongated member is disposed between the conductive coil and the plate.

[0013] In some embodiments, the flat panel comprises a flat panel display.

[0014] In yet other embodiments, the conductive coil is a first coil, and the electromagnetic system further includes a second conductive coil disposed on a common side of the elongated member with the first coil.

[0015] In some embodiments, the free vibrating end of the elongated member is a first end, and the elongated member extends away from the first position to a second end of the member that is free to vibrate in a direction perpendicular to the plane, the second end being opposite to the first end. The first coil may be arranged between the first position and the first end, and the second coil is arranged between the first position and the second end.

[0016] In some embodiments, the elongated member has a size in the range of from about 10 mm to about 50 mm and a thickness of 3 mm or less. In some embodiments, the elongated member has a stiffness and size such that the distributed mode loudspeaker has a resonant frequency in the range of from about 200 Hz to about 500 Hz.

[0017] On the other hand, a mobile device or wearable device includes a housing and a display panel mounted in the housing. The mobile device or wearable device also includes a flat plate extending in the panel plane. The mobile device or wearable device also includes a rigid slender member, the rigid slender member is displaced from the flat plate and extends parallel to the panel plane, the slender member is mechanically coupled to the flat plate at a first position along the slender member and extends away from the first position to the end of the member that vibrates freely in a direction perpendicular to the plane. The slender member includes a soft magnetic material. The mobile device or wearable device also includes an electromagnetic system, the electromagnetic system includes at least one conductive coil, the conductive coil has an axis perpendicular to the panel plane and is displaced from the slender member. The mobile device or wearable device also includes an electronic control module, the electronic control module is electrically coupled to the electromagnetic system and is programmed to fully energize the conductive coil so that the magnetic field generated by the conductive coil causes the free end of the slender member to be displaced perpendicular to the panel plane.

[0018] In some embodiments, the mobile device is a mobile phone or a tablet computer. In some embodiments, the wearable device is a smart watch or a head mounted display. Optionally, the mobile device or the wearable device may include any or all of the previously mentioned features of embodiments of the distributed mode speaker.

[0019] Among other advantages, embodiments feature electromagnetic (EM) actuators with fewer moving parts. For example, an EM actuator may include only a single moving part corresponding to an elongated member. Such actuators may be less susceptible to damage than, for example, conventional EM actuators. In particular, such actuators may be less susceptible to damage due to mechanical shock, such as dropping, than conventional EM actuators. Another advantage provided by the disclosed EM actuators is that they may be smaller and lighter than actuators that include permanent magnets. Additionally, the disclosed DMLs may be manufactured without the use of toxic materials such as lead. Another advantage provided by the disclosed EM actuators is that they may operate above the Curie temperature of certain magnets and piezoelectric devices. Thus, the disclosed EM actuators may be used as high temperature actuators, for example, actuators that operate in extreme environments.

[0020] Other advantages will be apparent from the description, drawings, and claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is a perspective view of an embodiment of a mobile device.

[0022] Figure 2 yes Figure 1 Schematic cross-sectional view of a mobile device.

[0023] Figure 3 is a cross section of a mobile device featuring an electromagnetic actuator 302 comprising a single electromagnet pair.

[0024] Figure 4 is a cross section of a mobile device featuring an electromagnetic actuator comprising two pairs of electromagnets.

[0025] Figure 5 is a cross section of a mobile device featuring an electromagnetic actuator comprising eight electromagnet pairs.

[0026] Figure 6 is a schematic diagram of an embodiment of an electronic control module for a mobile device.

[0027] Like reference numbers in the various drawings represent like elements. DETAILED DESCRIPTION

[0028] The present disclosure features an actuator for a panel audio speaker such as a distributed mode speaker (DML). Such a speaker can be integrated into a mobile device such as a mobile phone. For example, referring to Figure 1 , the mobile device 100 includes a device housing 102 and a touch panel display 104, the touch panel display 104 including a flat panel display (e.g., an OLED or LCD display panel) with integrated panel audio speakers. For ease of reference, Figure 1 A Cartesian coordinate system having x, y, and z axes is also included. The mobile device 100 interfaces with a user in various ways, including by displaying images and receiving touch input via the touch panel display 104. Typically, the mobile device has a depth (in the z direction) of approximately 10 mm or less, a width (in the x direction) of 60 mm to 80 mm (e.g., 68 mm to 72 mm), and a height (in the y direction) of 100 mm to 160 mm (e.g., 138 mm to 144 mm).

[0029] The mobile device 100 also generates audio output. The audio output is generated using a panel audio speaker that produces sound by vibrating the flat panel display. The display panel is coupled to an actuator, such as a distributed mode actuator or DMA. The actuator is a movable component arranged to provide force to a panel such as a touch panel display 104 to cause the panel to vibrate. The vibrating panel generates sound waves that can be heard by humans, for example in the range of 20 Hz to 20 kHz.

[0030] In addition to generating sound output, the mobile device 100 can also generate tactile output using the actuator. For example, the tactile output can correspond to vibrations in the range of 180 Hz to 300 Hz.

[0031] Figure 1 It also shows that the corresponding Figure 2 The dashed lines in the cross-sectional directions are shown in Fig. Figure 2 , a cross-section of the mobile device 100 shows the device housing 102 and the touch panel display 104. The device housing 102 has a depth measured along the z-direction and a width measured along the x-direction. The device housing 102 also has a back plate formed by a portion of the device housing 102 extending primarily in the xy plane. The mobile device 100 includes an actuator 210 housed in the housing 102 behind the display 104 and attached to the back of the display 104. Typically, the actuator 210 is sized to fit within a volume limited by other components housed in the housing, including an electronic control module 220 and a battery 230.

[0032] refer to Figure 3, the mobile device 300 shown in cross section features an electromagnetic actuator 302, which includes a pair of electromagnetic assemblies 310a and 310b outlined in dashed lines. The electromagnetic assemblies 310a and 310b are positioned on opposite sides of an elongated member 330. The member 330 is attached to the panel 104 by a short post 350. The member is attached to the short post 350 at one end, while the opposite end is free to vibrate. The electromagnetic assemblies are positioned on opposite sides of the elongated member 330 near the free end of the member. The electromagnetic assembly 310a is attached to a frame 320, which is attached to the frame 102 at one end. The frame 320 suspends the electromagnetic assembly 310a above the member 330. Below the member 330, the electromagnetic assembly 310b is attached to a spacer 340, which ensures that the electromagnetic assemblies 310a and 310b are spaced approximately the same distance measured in the z direction from the member 330.

[0033] Electromagnetic assemblies 310a and 310b each include a corresponding support structure 312a and 312b including a central magnetic pole supporting conductive coils 314a and 314b, respectively. Coils 314a and 314b are axially aligned parallel to the z-axis.

[0034] The magnetic components 310a and 310b can be relatively compact. For example, the width of the center pole can be about 3 mm to 8 mm when measured in the x-direction, and the width of the surrounding wall of the support structure can be about half the width of the center pole when measured in the x-direction. The height of the electromagnetic components 310a and 310b can be about 1 mm to 3 mm, for example 2 mm.

[0035] Typically, the elongated member 330 has a dimension in the xy plane that is significantly greater than its thickness (i.e., in the z direction). For example, the member 330 can be formed as a beam (e.g., where the dimension along the x direction is significantly greater than the y dimension and the thickness) or a plate (e.g., where the x and y dimensions are comparable and both are significantly greater than the thickness). For example, the x dimension can be about 10 mm to about 50 mm (e.g., about 12 mm to about 20 mm), and the thickness can be about 3 mm or less (e.g., 2 mm or less, 1 mm or less, 0.5 mm or less).

[0036] The material composition of member 330 is selected so that the member can be magnetized, i.e., magnetized by the magnetic field generated by electromagnetic assemblies 310a and 310b. Member 330 should also be rigid enough to support vibration modes introduced by displacement at the free ends of the member. Member 330 may include a soft magnetic material. Examples of soft magnetic materials include certain alloys, such as nickel-iron alloys (permalloy) and soft ferrites (e.g., iron cubes). In some embodiments, member 330 is made of steel (e.g., 1018 steel). It should be understood that the term "soft" used here describes the magnetic properties of the material, not its mechanical properties. Soft magnetic material is a material that is easily magnetized and demagnetized.

[0037] Typically, the placement of the electromagnetic assembly relative to the elongated member is selected based on a number of considerations including the amount of space available for the actuator within the chassis and the mechanical impedance of the elongated member. In some embodiments, the placement of the electromagnetic assembly relative to the elongated member is selected so that the mechanical impedance of the elongated member matches the mechanical impedance of the panel 104. In some cases, the closer the electromagnet is to the stub 350, the higher the mechanical impedance presented by the beam 330 to the electromagnetic system.

[0038] During operation of the actuator 302, the electronic control module 220 energizes one of the coils 314a and 314b by applying an AC current to the coil. In response, each coil generates a magnetic field that interacts with the member 330, causing the free end of the member to vibrate. Typically, the frequency, amplitude, and relative phase of the AC current supplied to the two coils are controlled to generate a desired frequency response in the member and, by coupling the member to the panel via the stub, a desired audio output of the panel. In some embodiments, the coils 314a and 314b are driven with AC currents having the same frequency but approximately 180° out of phase. When the coils 314a and 314b are no longer energized, the member 330 returns to a rest position, as shown in FIG. Figure 3 shown.

[0039] Periodically energizing coils 314a and 314b can cause actuator 302 to excite various vibration modes, including resonant modes, in panel 104. For example, a touch panel display can have a fundamental resonant frequency in a range from about 200 Hz to about 600 Hz (e.g., at about 500 Hz), and one or more additional higher-order resonant frequencies in a range from about 5 kHz to about 20 kHz.

[0040] Usually, although Figure 3 One configuration of the actuator is shown, but variations are possible. For example, while actuator 302 includes spacer 340, the spacer may be omitted, for example, when member 330 is positioned in the z-direction such that electromagnetic assemblies 310a and 310b are equidistant from the member.

[0041] In addition, although Figure 3 An embodiment of an actuator 302 having a member fixed at one end and free to vibrate at the other end and including a single electromagnetic assembly pair to activate the free end is shown, but other configurations are possible. For example, an embodiment may include more than one electromagnetic assembly pair. For example, Figure 4A mobile device 400 is shown in cross section including an actuator 402 including electromagnetic assemblies 310a and 310b and electromagnetic assemblies 410a and 410b. The actuator 402 includes a member 330 and a stud 350 attaching the member 330 approximately midway between two opposing ends of the member.

[0042] Actuator 402 also includes a pair of frames 420a and 420b that support electromagnetic assemblies 310a and 410a, respectively. Spacers 440a and 440b support electromagnetic assemblies 310b and 410b. Electromagnetic assemblies 310a and 310b are positioned on opposite sides of member 330 at one free end of the member, while components 410a and 410b are positioned on opposite sides at the other free end of member 330. Similar to components 310a and 310b, component 410a includes support structure 412a and coil 414a, while component 410b includes support structure 412b and coil 414b.

[0043] Just as the electronic control module 220 drives the actuator 302 so that only a subset is activated at a time, such as one of the two electromagnetic assemblies 310a and 310b, the electronic control module can drive the actuator 402 so that only a subset of the electromagnets 310a, 310b, 410a, and 410b are activated at a time. For example, the electronic control module 220 can periodically activate one of the four electromagnets at a time and cycle through each of the four electromagnets. As another example, the electronic control module 220 can periodically activate two of the four electromagnets at a time and cycle through two of the four electromagnets, such as so that electromagnets 310a and 410a are activated for a portion of the cycle, while electromagnets 310b and 410b are activated for the remainder of the cycle.

[0044] Although Figure 3 An actuator comprising a pair of electromagnets is shown, but a single electromagnet may be used. When a single electromagnet is used, the material properties of member 330 are selected so that when the electromagnet is not activated, the member returns to its rest position, as shown in FIG. Figure 3 In an embodiment including a single electromagnet, the AC signal used to drive the electromagnet can be offset in voltage so that the minimum of the waveform corresponds to the static position of the member 330. That is, the drive signal is biased so that it oscillates around the offset voltage, rather than, for example, zero volts. In this embodiment, the drive signal can be processed to remove distortion components that occur due to the varying forces on the member 330 as the member changes position relative to the electromagnet.

[0045] In some embodiments, the actuator may include multiple pairs of electromagnetic components arranged in two dimensions. Figure 5, the actuator 502 includes an upper frame 504, a lower frame 506, and an elongated member 530 positioned between the upper frame and the lower frame. The elongated member 530 is in the form of a plate extending in both the x and y directions. The upper frame 504 and the lower frame 506 are supported by short posts 510, which are attached to the corners of the upper frame at one end and to the equipment rack 102 at the opposite end. Between their attachment to the upper frame 504 and the equipment rack or other components within the mobile device, each short post 510 is also attached to the lower frame 506. The upper frame 504 includes a hole 508 through which the short post 350 passes. At one end, the short post 350 is attached to the panel 104, and at the opposite end, the short post is attached to the member 530.

[0046] Both upper frame 504 and lower frame 506 include a plurality of electromagnetic assemblies (examples are labeled 310a and 310b, respectively). Specifically, each frame includes eight electromagnetic assemblies arranged in a three by three grid (except for a center grid location where aperture 508 is located).

[0047] During operation, the member 530 vibrates in response to the periodic activation of the electromagnetic components of the upper frame 504 and the lower frame 506. The vibration force is transmitted to the panel 104 through the short column 350, thereby causing the panel 104 to vibrate and generate sound waves. The electronic control module 220 can selectively activate one or more of the electromagnets of the upper frame 504 and the lower frame 506. Arranging the electromagnetic components in a two-dimensional array promotes a two-dimensional vibration mode in the member 530.

[0048] Although Figure 5 A configuration including eight electromagnets is shown, but with Figure 5 Other configurations are possible with more or fewer electromagnets than those shown.

[0049] Typically, the actuator is controlled by an electronic control module (e.g. Figure 2 Typically, the electronic control module is composed of one or more electronic components that receive input from one or more sensors and / or signal receivers of the mobile phone, process the input, and generate and transmit a signal waveform that causes the actuator 210 to provide an appropriate tactile response. Figure 6 , an exemplary electronic control module 600 of a mobile device, such as the mobile device 100, includes a processor 610, a memory 620, a display driver 630, a signal generator 640, an input / output (I / O) module 650, and a network / communication module 660. These components are in electrical communication with each other (e.g., via a signal bus 602) and with the actuator 210.

[0050] Processor 610 may be implemented as any electronic device capable of processing, receiving or transmitting data or instructions. For example, processor 610 may be a microprocessor, a central processing unit (CPU), an application specific integrated circuit (ASIC), a digital signal processor (DSP), or a combination of these devices.

[0051] The memory 620 has various instructions, computer programs, or other data stored thereon. The instructions or computer programs may be configured to perform one or more of the operations or functions described with respect to the mobile device. For example, the instructions may be configured to control or coordinate the operation of the display of the device via the display driver 630, the signal generator 640, one or more components of the I / O module 650, one or more communication channels accessible via the network / communication module 660, one or more sensors (e.g., biometric sensors, temperature sensors, accelerometers, optical sensors, air pressure sensors, humidity sensors, etc.), and / or the actuator 210.

[0052] The signal generator 640 is configured to generate an AC waveform having a varying amplitude, frequency, and / or pulse profile suitable for the actuator 210 and producing an acoustic and / or tactile response via the actuator. Although depicted as a separate component, in some embodiments, the signal generator 640 may be part of the processor 610. In some embodiments, the signal generator 640 may include an amplifier, for example, as an integral part thereof or as a separate component.

[0053] The memory 620 can store electronic data that can be used by the mobile device. For example, the memory 620 can store electronic data or content, such as audio and video files, documents and applications, device settings and user preferences, timing and control signals, or data, data structures or databases for various modules. The memory 620 can also store instructions for reconstructing various types of waveforms that the signal generator 640 can use to generate signals for the actuator 210. The memory 620 can be any type of memory, such as random access memory, read-only memory, flash memory, removable memory, or other types of storage elements, or a combination of these devices.

[0054] As briefly discussed above, the electronic control module 600 may include Figure 6 650. Figure 6650, but the mobile device may include a number of different input components, including buttons, microphones, switches, and dials for accepting user input. In some embodiments, the components of I / O module 650 may include one or more touch sensors and / or force sensors. For example, the display of the mobile device may include one or more touch sensors and / or one or more force sensors that enable a user to provide input to the mobile device.

[0055] Each component of I / O module 650 may include dedicated circuitry for generating signals or data. In some cases, a component may generate or provide feedback for a dedicated input corresponding to a prompt or user interface object presented on a display.

[0056] As described above, network / communication module 660 includes one or more communication channels. These communication channels may include one or more wireless interfaces, which provide communication between processor 610 and external device or other electronic device. Typically, communication channels can be configured to transmit and receive data and / or signals that can be interpreted by instructions executed on processor 610. In some cases, external device is a part of an external communication network configured to exchange data with other devices. Typically, wireless interface may include but is not limited to radio frequency, light, sound and / or magnetic signals, and may be configured to operate via wireless interface or protocol. Example wireless interface includes radio frequency cellular interface, optical fiber interface, acoustic interface, Bluetooth interface, near field communication interface, infrared interface, USB interface, Wi-Fi interface, TCP / IP interface, network communication interface or any conventional communication interface.

[0057] In some embodiments, one or more of the communication channels of the network / communication module 660 may include a wireless communication channel between the mobile device and another device, such as another mobile phone, a tablet computer, a computer, etc. In some cases, the output, audio output, tactile output, or visual display element may be directly transmitted to another device for output. For example, an audible alarm or visual warning may be transmitted from the mobile device 100 to the mobile phone for output on the device, and vice versa. Similarly, the network / communication module 660 may be configured to receive input provided on another device to control the mobile device. For example, an audible alarm, a visual notification, or a tactile alarm (or an instruction therefor) may be transmitted from an external device to the mobile device for presentation.

[0058] The actuator technology disclosed herein can be used in a panel audio system, for example, designed to provide acoustic and / or tactile feedback. The panel can be a display system, for example, an OLED based on LCD technology. The panel can be part of a smart phone, a tablet computer, or a wearable device (e.g., a smart watch or a head-mounted device, such as smart glasses).

[0059] Other embodiments are within the following claims.

Claims

1. A device comprising: A flat plate extending in a plane; an actuator coupled to the plate and configured to couple vibration to the plate to cause the plate to vibrate, the actuator comprising: a stud coupled to a surface of the plate, the stud extending perpendicular to the surface of the plate; a cantilever member attached to the stud at a first location along the member, the member extending parallel to the plane; and a first conductive coil and a second conductive coil, each having a respective axis perpendicular to the plane, the first conductive coil and the second conductive coil being arranged on opposite sides of the cantilever member, the first conductive coil and the second conductive coil being each configured to generate a magnetic field during operation of the actuator, the magnetic field being sufficient to displace the cantilever member in a direction perpendicular to the plane.

2. The device according to claim 1, wherein: The cantilever member extends from the short post to a free end of the cantilever member, and the free end of the cantilever member is free to vibrate in the direction perpendicular to the plane.

3. The device according to claim 1, wherein: The first conductive coil and the second conductive coil are aligned along a common axis.

4. The device according to claim 1, wherein: During operation of the actuator, the first conductive coil and the second conductive coil are simultaneously energized to cause the cantilever member to vibrate.

5. The device according to claim 1, wherein: During operation of the actuator, current flowing through the first conductive coil is 180 degrees out of phase with current flowing through the second conductive coil.

6. The device according to claim 1, wherein: The stud displaces the cantilever member from the surface of the plate.

7. The device according to claim 1, wherein: The cantilever member is formed of a soft magnetic material.

8. The device according to claim 1, wherein: The cantilever member has a beam shape.

9. The device according to claim 1, wherein: The cantilever member has a plate shape.

10. The apparatus of claim 1, further comprising a rigid frame, the first conductive coil and the second conductive coil each being mechanically coupled to the rigid frame.

11. The device according to claim 10, wherein: The rigid frame mechanically grounds the first conductive coil and the second conductive coil.

12. The device according to claim 1, wherein: The flat panel includes a display panel.

13. The apparatus of claim 1, comprising an electronic control module electrically coupled to the first conductive coil and the second conductive coil and programmed to energize the first conductive coil and the second conductive coil.

14. The apparatus according to claim 2, wherein: The first conductive coil and the second conductive coil are each disposed between the stub and the free end of the cantilever member.

15. The apparatus according to claim 2, wherein: The actuator further includes a third conductive coil disposed on a common side of the cantilever member with the first conductive coil.

16. The device according to claim 15, wherein: The free end of the cantilever member is a first end, and the cantilever member extends from the first end to a second end opposite the first end.

17. The device according to claim 16, wherein: The first conductive coil is disposed between the stub and the first end, and the third conductive coil is disposed between the stub and the second end.

18. An actuator comprising: a stub configured to be coupled to a plate extending in a plane, the stub extending perpendicular to the plane when attached to the plate; a cantilever member attached to the stud at a first location along the member, the member extending parallel to the plane; as well as a first conductive coil and a second conductive coil, each having a respective axis perpendicular to the plane, the first conductive coil and the second conductive coil being arranged on opposite sides of the cantilever member, the first conductive coil and the second conductive coil being each configured to generate a magnetic field during operation of the actuator, the magnetic field being sufficient to displace the cantilever member in a direction perpendicular to the plane.

19. A mobile device comprising: case; A flat plate extending in a plane; an actuator coupled to the plate and configured to couple vibration to the plate to cause the plate to vibrate, the actuator comprising: a stud coupled to a surface of the plate, the stud extending perpendicular to the surface of the plate; a cantilever member attached to the stud at a first position along the member, the member extending parallel to the plane; and a first conductive coil and a second conductive coil, each having a respective axis perpendicular to the plane, the first conductive coil and the second conductive coil being arranged on opposite sides of the cantilever member, the first conductive coil and the second conductive coil being each configured to generate a magnetic field during operation of the actuator, the magnetic field being sufficient to displace the cantilever member in a direction perpendicular to the plane.

20. A device comprising: A flat plate extending in a plane; an actuator coupled to the plate and configured to couple vibration to the plate to cause the plate to vibrate, the actuator comprising: a stud coupled to a surface of the plate, the stud extending perpendicular to the surface of the plate; a cantilever member attached to the stud at a first location along the member, the member extending parallel to the plane from the stud to a first end and from the stud to a second end opposite the first end, the first and second ends of the cantilever member being free to vibrate in a direction perpendicular to the plane; a first conductive coil disposed between the stub and the first end; and a second conductive coil, the second conductive coil being arranged between the short post and the second end, wherein the first conductive coil and the second conductive coil each have an axis perpendicular to the plane, the first conductive coil and the second conductive coil are arranged on a common side of the cantilever member, and the first conductive coil and the second conductive coil are each configured to generate a magnetic field during operation of the actuator, the magnetic field being sufficient to displace the cantilever member in a direction perpendicular to the plane.

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