Patent Description:
<CIT> discloses an electro-mechanical and acoustic transducer capable of generating both strong vibration and sound. In an electro-mechanical and acoustic transducer disclosed therein, mass of a mechanical vibration system of the electro-mechanical and acoustic transducer is increased by attaching a weight to a magnetic circuit unit or integrated the weight with the magnetic circuit unit, whereby large vibration is obtained from the electro-mechanical and acoustic transducer.

<CIT> discloses a system which includes a device chassis with a back panel and a haptic conduction interface. An acoustic radiating panel, attached to the chassis, and the back panel define a space. A moving magnet actuator is positioned in the space and mechanically coupled to the acoustic radiating panel, the moving magnet actuator including an element having a thickness smaller than a first dimension of the space, the moving magnet actuator being configured to vibrate the element during operating. An electronic control module coupled to the moving magnet actuator is programmed to activate the moving magnet actuator with a haptic signal that displaces the element in the first direction an amount sufficient to cause the element to contact the haptic conduction interface, the haptic signal having an amplitude and frequency sufficient to generate a haptic response in the device chassis. <CIT> discloses an actuator module with a magnetic assembly comprising concentric cup, coil and center magnet of quadrilateral shape with rounded corners. The cup comprises four sidewalls and is suspended by means of a plurality of springs attached to a rigid frame, wherein the coil and the rigid frame are attached to a cover plate.

Disclosed are actuator modules with improved damage resistance compared to conventional modules. The actuator modules may be suitable for panel audio loudspeakers, especially those incorporated in mobile devices (e.g., mobile phones). For example, implementations of such actuator modules feature components, such as a back plate, suspension, and a frame, which are configured to effectively dissipate a force that results from the actuator module being dropped, therefore preventing damage to the components of the actuator module.

In general, in a first aspect, there is provided a panel audio loudspeaker as claimed in claim <NUM>.

Implementations of the method can include one or more of the following features. In some implementations, a width of each spring varies along a length of the spring.

The sidewalls can each comprise a portion of a ring magnet. The center magnet and the ring magnet can have their corresponding magnetic poles aligned in opposite directions. In some implementations, the magnetic pole of the center magnet is aligned parallel to the coil axis and the magnetic pole of the ring magnet is aligned parallel to the coil axis.

In some implementations, the sidewalls each include a portion of a front ring plate formed from a soft magnetic material, the ring magnet being arranged between the front ring plate and the back plate. In other implementations, the sidewalls each include an outer surface facing the frame, and a section of the outer surface formed by the ring magnet is recessed relative to a section of the outer surface formed by the front ring plate.

The inner element can include a front center plate comprising a soft magnetic material, the center magnet being arrangement between the front center plate and the back plate. In some implementations, the inner element comprises a bucking magnet on an opposite side of the front center plate from the center magnet. The center magnet and bucking magnet can have their corresponding magnetic poles aligned in opposite directions. The magnetic pole of the center magnet can be aligned parallel to the coil axis and the magnetic pole of the bucking magnet can be aligned parallel to the coil axis.

In some implementations, the springs allow the magnet assembly to vibrate in a first natural resonant mode in a direction along the coil axis and in a second natural resonant mode perpendicular to the coil axis, a frequency of the second natural resonant mode, f2, being greater than a frequency of the first natural resonant mode, f1. The second natural resonant mode, f2, can be approximately two times the first natural resonant mode, f1.

In some implementations, the actuator module further includes a hood enclosing the magnet assembly and voice coil in a space defined by the hood and the base plate.

In another aspect, there is provided a mobile device or wearable device as claimed in claim 14The mobile device can be a mobile phone or a tablet computer. The wearable device can be a smart watch or head-mounted display.

Among other advantages, embodiments feature an actuator module that has a decreased chance of failure from mechanical stress caused by the actuator module being dropped, as compared to conventional actuator modules.

Other advantages will be evident from the description, drawings, and claims.

Referring to <FIG>, an actuator module <NUM> includes a hood <NUM>, a motor module <NUM>, a voice coil <NUM>, and a baseplate <NUM>. A printed circuit board (PCB) <NUM> is attached to baseplate <NUM> on one side, and a pressure sensitive adhesive (PSA) <NUM> is attached on the other side of the baseplate. Hood <NUM>, motor module <NUM>, and voice coil <NUM> are all connected to baseplate <NUM>, with the hood and the baseplate forming an enclosure that protects the motor module <NUM> and the voice coil. PSA <NUM> allows module <NUM> to be affixed to a panel, such as a flat panel display of a mobile device. A Cartesian coordinate system is shown in <FIG> for reference.

Actuator module <NUM> can be relatively compact. For example, hood <NUM>, which has a substantially square profile in the x-y plane, can have an edge length (i.e., in the x- or y-directions) of about <NUM> or less (e.g., <NUM> or less, <NUM> or less, such as <NUM>, <NUM>, <NUM> or less). The actuator module's height (i.e., its dimension in the z-direction) can be about <NUM> or less (e.g., <NUM> or less, <NUM> or less, <NUM> or less).

During operation, an electric current is applied to voice coil <NUM> via PCB <NUM>. The resulting magnetic flux interacts with a suspended magnet that is part of motor module <NUM> (discussed below), and the resulting vibrations are transferred via baseplate <NUM> to the panel.

Referring to <FIG>, motor module <NUM> includes a frame <NUM>, a magnet assembly, and a pair of springs 202a and 202b that suspends the magnet assembly from the frame. The magnet assembly includes a back plate <NUM> to which a center magnet <NUM> and a ring magnet <NUM> are attached. Back plate <NUM> and ring magnet <NUM> can make up a magnetic cup, having sidewalls defined by the inside edge of the ring magnet. Center magnet <NUM> and ring magnet <NUM> are sized and shaped so that the center magnet fits within a gap defined by the ring magnet, as shown by their relative placement in <FIG>. The gap between center magnet <NUM> and ring magnet <NUM> can be about <NUM> or less (e.g., <NUM> or less, <NUM> or less, <NUM> or less, <NUM> or less).

The magnet assembly also includes a front center plate <NUM> and a front ring plate <NUM>, which are attached to bottom surfaces of center magnet <NUM> and ring magnet <NUM>, respectively. The magnet assembly further includes a bucking magnet <NUM>, which is attached to front center plate <NUM>. Front center plate <NUM> and front ring plate <NUM> are sized and shaped so that the front center plate fits with a gap defined by the front ring plate, as shown by their relative placement in <FIG>. Front center plate <NUM> and front ring plate <NUM> can be soft magnetic materials, e.g., ones having a high relative permeability. For example, the soft magnetic material may have a relative permeability of about <NUM> or more (e.g., about <NUM>,<NUM> or more, about <NUM>,<NUM> or more). Examples include high carbon steel and vanadium permendur. In some embodiments, the soft magnetic material can be a corrosion resisting high permeability alloy such as a ferritic stainless steel.

At each corner of frame <NUM> are posts 204a-204d that attach the frame to hood <NUM> and baseplate <NUM>. That is, top surfaces of posts 204a-204d are attached to hood <NUM>, while bottom surfaces of the posts are attached to baseplate <NUM>. Frame <NUM> also includes stubs 204e-<NUM>, which are positioned on the sides of the frame, between two of posts 204a-204d. Stubs 204e and <NUM> each have a bottom surface that attaches to baseplate <NUM>.

While frame <NUM> has an approximately square shape when viewed in the xy-plane, each corner of the frame is curved so that the frame has dull corners. Between each of the corners of frame <NUM> are portions of the frame that are substantially straight along their outside edges. The straight portions of frame <NUM> attach the frame to hood <NUM>. Stubs 204e-<NUM> extend in the z-direction allowing for an increased area of contact with hood <NUM>, as compared to a frame that does not include the stubs.

While the straight portions of frame <NUM> attach to hood <NUM>, the outside edge of springs 202a and 202b do not contact hood <NUM>. That is, a first distance measured between the inside edge of hood <NUM> and the outside edge of spring 202a or 202b is greater than a second distance measured between the inside edge of hood <NUM> and the outside edge of the straight portions of frame <NUM>, where the first and second distances are measured parallel to the x or y-axes.

Spring 202a is attached (e.g., welded) to frame <NUM> at connection points 216a and 216b. Spring 202b is attached to frame <NUM> at a connection point 218c. While obscured in the view of <FIG>, spring 202b is attached to frame <NUM> at an additional connection point that is symmetric to connection point 218c about an axis <NUM> that runs parallel to the y-axis.

Springs 202a and 202b share approximately the same shape when viewed in the xy-plane. The corners of springs 202a and 202b, as viewed in the xy-plane, are curved. Two sides of springs 202a and 202b, between the corners of the springs, are substantially straight. The remaining two sides of springs 202a and 202b are curved inward in a "c" shape. One example of the benefit provided by the c-shaped portions of springs 202a and 202b is that they allow stubs 204e-<NUM> to extend in the z-direction.

Spring 202a is attached to back plate <NUM> at connection points 206a and 206b. Back plate <NUM> includes two slots at the locations of connection points 206a and 206b, so that spring 202a is significantly flush with the top surface of the back plate. The shape of the slots of back plate <NUM> are curved in approximately the same c-shaped curvature as are springs 202a and 202b. The c-shaped portions of spring 202a and the corresponding c-shaped slot of back plate <NUM> facilitate the connection between these components at connection points 206a and 206b.

A width of each spring 202a and 202b varies along a length of the spring. For example, a first width of spring 202a at connection point 216a or 216b is greater than a second width of the spring at the corners of the spring. The first width can be about <NUM> or less (e.g., <NUM> or less, <NUM> or less, <NUM> or less), while the second width can be about <NUM> or less (e.g., <NUM> or less, <NUM> or less, <NUM> or less). Similarly, a third width of spring 202a at connection points 206a or 206b is greater than the second width of the spring. The third width can be about <NUM> or less (e.g., <NUM> or less, <NUM> or less, <NUM> or less). The width of the spring decreases as it extends along any midpoint that is on the spring and between two corners of the spring to any corner of the spring. That is, as spring 202a extends from connection point 206a or 206b to a closest corner of the spring, the width of the spring decreases. Similarly, as spring 202a extends from connection point 216a or 216b to a closest corner of the spring, the width of the spring decreases.

While spring 202a is attached to back plate <NUM>, spring 202b is attached to a bottom surface of front ring plate <NUM>. <FIG> shows where spring 202b is attached to front ring plate <NUM> at a connection point 214a. While obscured in the view of <FIG>, spring 202b is attached to front ring plate <NUM> at a connection point 214b, which is symmetric about an axis <NUM> that runs parallel to the x-axis. Just as back plate <NUM> includes c-shaped slots at the locations of connection points 216a and 216b, front ring plate <NUM> also includes corresponding c-shaped slots at the locations where spring 202b connects to the front ring plate.

During the operation of actuator module <NUM>, springs 202a and 202b bend in the z-direction. By virtue of their connection to springs 202a and 202b, back plate <NUM>, center magnet <NUM>, ring magnet <NUM>, front center plate <NUM>, front ring plate <NUM>, and bucking magnet <NUM> also move in the z-direction. The locations of the connections of springs 202a and 202b to motor module <NUM> are chosen so that the motor module has a desired resonant frequency.

Spring 202b includes c-shaped notches that correspond with connection point 214a and connection point 214b (not shown). The location of connection points 206a and 206b to baseplate <NUM> and connection points 214a and 214b to front ring plate <NUM> can be chosen to facilitate motor module <NUM> to exhibit a desired resonant behavior. For example, connection points 206a and 206b are not placed above connection points 214a and 214b. This placement of the connection points facilitates motor module <NUM> to exhibit a desired resonant behavior, e.g., to facilitate the motor module to exhibit a desired rocking mode.

For example, if actuator module <NUM> is dropped, springs 202a and 202b and their corresponding connection points can facilitate motor module <NUM>, e.g., the magnet assembly of the motor module, to exhibit a rocking mode. The frequency of the rocking mode can be at roughly twice a resonant frequency displayed by motor module <NUM>. Because the rocking mode is at roughly twice the resonant frequency of motor module <NUM>, it is not a favorable excitation for the motor module during normal operation. However, because the rocking mode is the first normal mode above the resonant frequency, motor module <NUM> can exhibit the rocking mode if actuator module <NUM> is dropped, and the force of the impact can be at least partially dissipated by the rocking mode.

The thickness to width ratio of the springs, favors displacement of motor module <NUM> in the z-direction over displacement of the motor module in the x or y-directions. However, during abnormal operation of actuator module <NUM>, such as when the actuator is dropped, there may be some lateral displacement (e.g., displacement in the x or y-directions) of motor module <NUM>. The lateral displacement causes uneven forces in the z-direction, causing the rocking mode which dissipates the energy of the drop over time.

Not only can the placement of the connection points 216a, 216b, 214a, and 214b be chosen to facilitate a desired resonant behavior of motor module <NUM>, the shape of springs 202a and 202b can affect the resonant behavior of the motor module. For example, the thickness of springs 202a and 202b, as measured in the z-direction, or the width of the springs, as measured in the x and y-directions, can be increased or decreased to promote a desired resonant behavior of motor module <NUM>, e.g., to promote a certain fundamental frequency. In addition, the thickness of frame <NUM> or the width of the frame can be increased or decreased to promote a desired resonant behavior of motor module <NUM>.

The dimensions of springs 202a and 202b, as measured in the x and y-dimensions, can be approximately equal. For example, springs 202a and 202b can fit within a square having side lengths of about <NUM> or less (e.g., <NUM> or less, <NUM> or less, <NUM> or less, <NUM> or less). Springs 202a and 202b can be made from a hard alloy having a high yield strength, e.g., a yield strength of <NUM> MPa or greater. For example, springs 202a and 202b can be made from <NUM> stainless steel.

Referring now to <FIG>, a cross-sectional view of actuator module <NUM> shows an air gap <NUM>, which separates center magnet <NUM> and ring magnet <NUM>, as well as front center plate <NUM> and front ring plate <NUM>. Voice coil <NUM> is positioned in air gap <NUM>. Center magnet <NUM>, ring magnet <NUM>, and bucking magnet <NUM> generate magnetic fields which pass perpendicularly to voice coil <NUM>, i.e., in the x-direction. <FIG> also shows the relative polarities of each magnet, shown as "N" and "S". Center magnet <NUM> and ring magnet <NUM> have their corresponding magnetic poles aligned in opposite directions.

During the operation of actuator module <NUM>, voice coil <NUM> is energized. When energized, voice coil <NUM> induces a magnetic field in air gap <NUM>. Center magnet <NUM> and ring magnet <NUM> each experience a force due to the interaction of their magnetic fields with that induced by voice coil <NUM>. The force experienced by center magnet <NUM> and ring magnet <NUM> cause these components to be displaced in the z-direction. By virtue of their respective connections, back plate <NUM>, front center plate <NUM>, front ring plate <NUM>, and bucking magnet <NUM> are displaced in the z-direction during operation of actuator assembly <NUM>.

Bucking magnet <NUM> is provided to focus the magnetic field generated by center magnet <NUM> and ring magnet <NUM>, so that the magnetic flux passing though voice coil <NUM> along the x-axis is maximized. The polarity of bucking magnet <NUM> is chosen to oppose the magnetic flux of center magnet <NUM> and ring magnet <NUM>. That is, center magnet <NUM> and bucking magnet <NUM> have their corresponding magnetic poles aligned in opposite directions. Bucking magnet <NUM> can also reduce the stray magnetic flux generated by center magnet <NUM> and ring magnet <NUM>, e.g., reduce the magnetic flux that does not pass perpendicularly to voice coil <NUM>.

During normal operation of actuator module <NUM>, moving components of the actuator are displaced primarily in the z-direction. Outside of normal operation, the moving components of the module may be displaced in the x or y-directions, e.g., as a result of the module being dropped, or as a result of a mobile device that includes the module being dropped. Displacement in the x or y-directions of the moving components can cause damage to actuator module <NUM>. Accordingly, hood <NUM> and frame <NUM> serve as physical stops to prevent significant displacement of the moving components of actuator module <NUM>.

For example, when actuator module <NUM> is dropped, baseplate <NUM>, front ring plate <NUM>, or both may contact frame <NUM>, preventing further displacement of these components in the x or y-directions. Baseplate <NUM> and front ring plate <NUM> can be made from one or more materials that are able to withstand the shock caused by contacting frame <NUM>. These components are also sized to prevent ring magnet <NUM> from contacting frame <NUM>, therefore preventing the magnet from being damaged as a result of contacting the frame. For example, a section of the outer surface formed by ring magnet <NUM> is recessed relative to a section of the outer surface formed by front ring plate <NUM>. Similarly, a section of the output surface formed by ring magnet <NUM> is recessed relative to a section of the outer surface formed by baseplate <NUM>. One of the recessed portions of ring magnet <NUM> is accented by a white dotted line <NUM>. In other words, a first gap between an inner surface of frame <NUM> and the outer surface of front ring plate <NUM> and a second gap between the inner surface of frame <NUM> and an outer surface of baseplate <NUM> are smaller than a third gap between the inner surface of the frame and the outer surface of ring magnet <NUM>. For example, the difference between the first and third gaps and the second and third gaps can be about <NUM> or less (e.g., <NUM> or less, <NUM> or less, <NUM> or less).

Similarly, to protect ring magnet <NUM>, a section of the inner surface formed by the ring magnet is recessed relative to a section of the inner surface of front ring plate <NUM>. One of the recessed portions of ring magnet <NUM> is accented by a white dotted line <NUM>. In other words, a gap between voice coil <NUM> and front ring plate <NUM> is smaller than a gap between the voice coil and ring magnet <NUM>. This relative spacing prevents ring magnet <NUM> from contacting voice coil <NUM>.

Similarly, to protect center magnet <NUM>, a section of the outer surface formed by the center magnet is recessed relative to a section of the outer surface formed by front center plate <NUM>. One of the recessed portions of center magnet <NUM> is accented by a white dotted line <NUM>. In other words, A gap between voice coil <NUM> and front center plate <NUM> is smaller than a gap between voice coil <NUM> and center magnet <NUM>. This relative spacing prevents center magnet <NUM> from contacting voice coil <NUM>.

The relative shape of other components of actuator module <NUM> can be chosen to prevent damage that may be caused by the module being dropped. For example, back plate <NUM> can be shaped so as to efficiently dissipate the forces generated when actuator module <NUM> is dropped. <FIG> is a top view of frame <NUM> and back plate <NUM>. <FIG> shows how the corners of back plate <NUM> are shaped to dissipate forces that could otherwise damage components of actuator module <NUM>. For example, the arcs that form the corners of back plate <NUM> are chosen so the portion of the baseplate that impacts frame <NUM> is large enough to effectively dissipate the impact force. If back plate <NUM> or front ring plate <NUM> make contact with frame <NUM>, hood <NUM> can prevent the frame from being significantly displaced as a result of the force exerted on it by the back plate or the front ring plate. In some embodiments, the radius of curvature of the inside corner arc of voice coil <NUM> and the radius of curvature of the outside corner arc of front ring plate <NUM> are approximately the same. In certain embodiments, the radius of curvature of the outside corner arc of voice coil <NUM> and the radius of curvature of the inside corner arc of front ring plate <NUM> are approximately the same.

Referring to <FIG>, each corner of frame <NUM> is closest to a corresponding corner of voice coil <NUM>, back plate <NUM>, front center plate <NUM>, and front ring magnet <NUM>. The corners of some or all of voice coil <NUM>, back plate <NUM>, front center plate <NUM>, and front ring magnet <NUM> are concentric. Concentric corners are corners that form arcs whose circles of best fit are concentric with respect to one another. For example, referring to <FIG>, a corner of voice coil <NUM> is concentric with a corresponding corner of front ring magnet <NUM>. That is, a circle that best fits the arc formed by the corner of voice coil <NUM> is concentric with a circle that best fits the arc formed by a corresponding corner of front ring magnet <NUM>.

Concentric corners can nest within one another, allowing a greater surface area of contact between the corners, as compared to the surface area of contact between corners that are not concentric. Accordingly, the corresponding corners of voice coil <NUM>, front center plate <NUM>, and front ring magnet <NUM> are concentric with respect to one another.

Similarly, the shapes of the corners of other components of actuator module <NUM> can be chosen so that the corners that may contact one another when the module is dropped have a large enough surface area to effectively dissipate forces generated during the drop. <FIG> is a top view of voice coil <NUM>, frame <NUM>, front center plate <NUM>, and front ring plate <NUM>. The radii of curvature of the corners of front center plate <NUM> and front ring plate <NUM> are chosen so as to maximize the contacting surface area between these components and voice coil <NUM> if actuator module <NUM> is dropped, thereby distributing any force associated with impact between the two components at the corners over a greater area. The shape of an inner edge <NUM> of front ring plate <NUM> is chosen so as to maximize its contact with an outer edge <NUM> of voice coil <NUM> if the front ring plate is displaced in the x and/or y-directions, e.g., if actuator module <NUM> is dropped. The shape of an inner edge <NUM> of voice coil <NUM> is chosen so as to maximize its contact with an outer edge <NUM> of front center plate <NUM> if the front center plate is displaced in the x and/or y-directions, e.g., if actuator module <NUM> is dropped.

To further help maximize the contacting surface area between voice coil <NUM> and front ring plate <NUM> during displacement in the x and/or y-directions, a distance, d<NUM>, between the outside corner arc of voice coil <NUM> and the inside corner arc of front ring plate <NUM> is larger than a distance, d'<NUM>, between the outside middle edge of the voice coil and the inside middle edge of the front ring plate. Similarly, a distance, d<NUM>, between the outside corner arc of front center plate <NUM> and the inside corner arc of voice coil <NUM> is larger than a distance, d'<NUM>, between the outside middle edge of the front center plate and the inside middle edge of the voice coil.

In some embodiments, actuator module <NUM> can include a damping material between all or some of the edges of components that may make contact with one another, e.g., if actuator module <NUM> is dropped. For example, a damping material can be positioned between an inner edge <NUM> of frame <NUM> and an outer edge <NUM> of baseplate <NUM>. In some embodiments, a damping material can be placed between inner edge <NUM> of front ring plate <NUM> and outer edge <NUM> of voice coil <NUM>. In other embodiments, a damping material can be placed between inner edge <NUM> of voice coil <NUM> and outer edge <NUM> of front center plate <NUM>.

In some embodiments, a damping material can be positioned between a top surface of baseplate <NUM> and a bottom surface of hood <NUM>. In other embodiments, a damping material can be positioned between hood <NUM> and frame <NUM>. The damping material can be any material that is able to reduce the force of impact between components that contact one another. For example, the damping material can be a foam, a pressure sensitive adhesive, a ferrofluid, or a compliant polymer, e.g., one having a low stiffness and high elongation after curing.

The components of actuator module <NUM> are packaged together, as illustrated in <FIG>, which are a perspective top view and a perspective bottom view of the actuator module, respectively. Referring to <FIG>, PCB <NUM> is positioned above baseplate <NUM>. PCB <NUM> is a substrate for electronic components that interface with actuator module <NUM>. For example, PCB <NUM> can connect to electronic components that control the operation of actuator module <NUM>. PCB <NUM> can be wholly or partly flexible. PCB <NUM> extends in the x-direction, e.g., to include a large enough surface area for the electrical components that are printed on its surface. PCB <NUM> can also include a ring-shaped structure that is housed within and enclosed by hood <NUM>.

In addition to serving as an enclosure for the other components of actuator module <NUM>, hood <NUM> also provides magnetic shielding. When actuator module <NUM> is housed in a mobile device, it is advantageous to reduce the magnetic flux present outside of hood <NUM>, e.g., so that other electronic components of the mobile device are not affected by the magnetic fields generated by the magnets and voice coil <NUM>. Accordingly, the material properties of hood <NUM> are chosen to provide the desired magnetic shielding. For example, the magnetic permeability of the one or more materials chosen for hood <NUM> should be high enough so that the hood acts as a shield, but not so high that the hood promotes the formation of magnetic fields that may be present as a result of other components housed in the mobile device. For example, the material or materials of hood <NUM> may have a relative permeability equal to or more than <NUM>, equal to or more than <NUM>, or equal to or more than <NUM>. Examples include high carbon steel and vanadium permendur.

While the foregoing figures cover a specific embodiment of an actuator module, i.e., actuator module <NUM>, more generally the principles embodied in this example can be applied in other designs too. For example, while magnet motor <NUM> has a substantially square footprint (i.e., in the x-y plane), other shapes are possible, such as substantially rectangular, oval, or round.

While actuator module <NUM> includes three magnets, in some implementations, an actuator module can include one, two, three, or more magnets. For example, while actuator module <NUM> includes ring magnet <NUM> and center magnet <NUM>, in some embodiments, an actuator module can include either the ring magnet or the center magnet and one or more bucking magnets. In other embodiments, an actuator module can include either ring magnet <NUM> or center magnet <NUM> and no bucking magnet <NUM>.

In some embodiments, an actuator module can include a cup magnet module, e.g., a magnet positioned in a cup made of a permeable material, such as steel. In some embodiments, the cup magnet module can be accompanied by one or more bucking magnets, while in other embodiments, an actuator module can include the cup magnet module and no bucking magnet.

In some embodiments, an actuator module can include a ring magnet, a yoke, and no bucking magnet. In other embodiments, an actuator module can include a ring magnet, a yoke, and one or more bucking magnets.

In some embodiments, the actuator module can include one or more radially magnetized magnets accompanied by zero, one, or more bucking magnets.

The magnets of actuator module <NUM> can be an iron magnet, a neodymium magnet, or a ferrite magnet, such as one composed of iron and nickel. In some embodiments, one or more of the magnets of actuator module <NUM> can be replaced by an electromagnet. In some embodiments, actuator module <NUM> can include high permeability materials.

In general, the relative polarities of the magnets, as shown with respect to <FIG>, should be respected, such that reversing the polarity of one of the magnets shown in <FIG> should be accompanied by a reversal of the polarities of the other magnets.

In general, the actuator modules described above can be used in a variety of applications. For example, in some embodiments, actuator module <NUM> can be used to drive a panel of a panel audio loudspeaker, such as a distributed mode loudspeaker (DML). Such loudspeakers can be integrated into a mobile device, such as a mobile phone. For example, referring to <FIG>, a mobile device <NUM> includes a device chassis <NUM> and a touch panel display <NUM> including a flat panel display (e.g., an OLED or LCD display panel) that integrates a panel audio loudspeaker. Mobile device <NUM> interfaces with a user in a variety of ways, including by displaying images and receiving touch input via touch panel display <NUM>. Typically, a mobile device has a depth (in the z-direction) of approximately <NUM> or less, a width (in the x-direction) of <NUM> to <NUM> (e.g., <NUM> to <NUM>), and a height (in the y-direction) of <NUM> to <NUM> (e.g., <NUM> to <NUM>).

Mobile device <NUM> also produces audio output. The audio output is generated using a panel audio loudspeaker that creates sound by causing the flat panel display to vibrate. 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 a force to a panel, such as touch panel display <NUM>, causing the panel to vibrate. The vibrating panel generates human-audible sound waves, e.g., in the range of <NUM> to <NUM>.

In addition to producing sound output, mobile device <NUM> can also produce haptic output using the actuator. For example, the haptic output can correspond to vibrations in the range of <NUM> to <NUM>.

<FIG> also shows a dashed line that corresponds to the cross-sectional direction shown in <FIG>. Referring to <FIG>, a cross-section of mobile device <NUM> illustrates device chassis <NUM> and touch panel display <NUM>. Device chassis <NUM> has a depth measured along the z-direction and a width measured along the x-direction. Device chassis <NUM> also has a back panel, which is formed by the portion of device chassis <NUM> that extends primarily in the xy-plane. Mobile device <NUM> includes actuator module <NUM>, which is housed behind display <NUM> in chassis <NUM> and attached to the back side of display <NUM>. For example, PSA <NUM> can attach actuator module <NUM> to display <NUM>. Generally, actuator module <NUM> is sized to fit within a volume constrained by other components housed in the chassis, including an electronic control module <NUM> and a battery <NUM>.

In general, the disclosed actuators are controlled by an electronic control module, e.g., electronic control module <NUM> in <FIG> above. In general, electronic control modules are 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 deliver signal waveforms that cause actuator module <NUM> to provide a suitable haptic response. Referring to <FIG>, an exemplary electronic control module <NUM> of a mobile device, such as mobile device <NUM>, includes a processor <NUM>, memory <NUM>, a display driver <NUM>, a signal generator <NUM>, an input/output (I/O) module <NUM>, and a network/communications module <NUM>. These components are in electrical communication with one another (e.g., via a signal bus <NUM>) and with actuator module <NUM>.

Processor <NUM> may be implemented as any electronic device capable of processing, receiving, or transmitting data or instructions. For example, processor <NUM> can be a microprocessor, a central processing unit (CPU), an application-specific integrated circuit (ASIC), a digital signal processor (DSP), or combinations of such devices.

Memory <NUM> 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 device's display via display driver <NUM>, signal generator <NUM>, one or more components of I/O module <NUM>, one or more communication channels accessible via network/communications module <NUM>, one or more sensors (e.g., biometric sensors, temperature sensors, accelerometers, optical sensors, barometric sensors, moisture sensors and so on), and/or actuator module <NUM>.

Signal generator <NUM> is configured to produce AC waveforms of varying amplitudes, frequency, and/or pulse profiles suitable for actuator module <NUM> and producing acoustic and/or haptic responses via the actuator. Although depicted as a separate component, in some embodiments, signal generator <NUM> can be part of processor <NUM>. In some embodiments, signal generator <NUM> can include an amplifier, e.g., as an integral or separate component thereof.

Memory <NUM> can store electronic data that can be used by the mobile device. For example, memory <NUM> can store electrical data or content such as, for example, audio and video files, documents and applications, device settings and user preferences, timing and control signals or data for the various modules, data structures or databases, and so on. Memory <NUM> may also store instructions for recreating the various types of waveforms that may be used by signal generator <NUM> to generate signals for actuator module <NUM>. Memory <NUM> may be any type of memory such as, for example, random access memory, read-only memory, Flash memory, removable memory, or other types of storage elements, or combinations of such devices.

As briefly discussed above, electronic control module <NUM> may include various input and output components represented in <FIG> as I/O module <NUM>. Although the components of I/O module <NUM> are represented as a single item in <FIG>, 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 <NUM> may include one or more touch sensor and/or force sensors. For example, the mobile device's display 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.

Each of the components of I/O module <NUM> may include specialized circuitry for generating signals or data. In some cases, the components may produce or provide feedback for application-specific input that corresponds to a prompt or user interface object presented on the display.

As noted above, network/communications module <NUM> includes one or more communication channels. These communication channels can include one or more wireless interfaces that provide communications between processor <NUM> and an external device or other electronic device. In general, the communication channels may be configured to transmit and receive data and/or signals that may be interpreted by instructions executed on processor <NUM>. In some cases, the external device is part of an external communication network that is configured to exchange data with other devices. Generally, the wireless interface may include, without limitation, radio frequency, optical, acoustic, and/or magnetic signals and may be configured to operate over a wireless interface or protocol. Example wireless interfaces include radio frequency cellular interfaces, fiber optic interfaces, acoustic interfaces, Bluetooth interfaces, Near Field Communication interfaces, infrared interfaces, USB interfaces, Wi-Fi interfaces, TCP/IP interfaces, network communications interfaces, or any conventional communication interfaces.

In some implementations, one or more of the communication channels of network/communications module <NUM> may include a wireless communication channel between the mobile device and another device, such as another mobile phone, tablet, computer, or the like. In some cases, output, audio output, haptic output or visual display elements may be transmitted directly to the other device for output. For example, an audible alert or visual warning may be transmitted from the mobile device <NUM> to a mobile phone for output on that device and vice versa. Similarly, the network/communications module <NUM> may be configured to receive input provided on another device to control the mobile device. For example, an audible alert, visual notification, or haptic alert (or instructions therefor) may be transmitted from the external device to the mobile device for presentation.

The actuator technology disclosed herein can be used in panel audio systems, e.g., designed to provide acoustic and / or haptic feedback. The panel may be a display system, for example based on OLED of LCD technology. The panel may be part of a smartphone, tablet computer, or wearable devices (e.g., smartwatch or head-mounted device, such as smart glasses).

Claim 1:
A panel audio loudspeaker, comprising:
an actuator module (<NUM>), comprising:
a base plate (<NUM>) extending in a plane;
a voice coil (<NUM>) connected to the base plate, the voice coil defining a coil axis perpendicular to the plane;
a magnet assembly comprising:
a back side facing the base plate and a front side facing away from the base plate,
a base layer and sidewalls (<NUM>) defining a cup,
an inner element comprising a center magnet (<NUM>) mounted within the cup, and
a back plate (<NUM>) extending parallel to the plane,
wherein, the sidewalls comprise a first pair of sidewalls on opposing sides of the cup and a second pair of sidewalls on opposing sides of the cup and adjacent to the first pair of sidewalls, the sidewalls and inner element being separated by an air gap, and wherein an inner surface of the four sidewalls or the inner element of the magnet assembly defines a first quadrilateral shape with rounded corners, and the voice coil defines a second quadrilateral shape with rounded corners, the rounded corners of both the first and second quadrilateral shapes being concentric;
a rigid frame (<NUM>) attached to the base plate, the rigid frame comprising four stubs (204e-<NUM>) each facing a corresponding one of the sidewalls; and
a plurality of springs suspending the magnet assembly relative to the frame and base plate so that the voice coil extends into the air gap,
the plurality of springs comprising a first spring (202a) attached to the frame at a first pair of the four stubs respectively facing the first pair of sidewalls and attached to the magnet assembly at the second pair of sidewalls on the front side of the magnet assembly,
the plurality of springs comprising a second spring (202b) attached to the frame at a second pair of the four stubs respectively facing the second pair of sidewalls and attached to the magnet assembly at the first pair of sidewalls on the back side of the magnet assembly, the panel audio loudspeaker further comprising:
a panel attached to the base plate of the actuator module.