Electronic device having a tuned resonance haptic actuation system

An electronic device includes an enclosure, a display positioned with the enclosure and defining a front face of the electronic device, and a haptic actuator positioned within the enclosure. The haptic actuator includes a housing comprising a wall and a movable mass positioned within the housing and configured to move within the housing to cause the haptic actuator to produce a vibrational response. The vibrational response includes a first component within a frequency range and a second component outside of the frequency range and providing a haptic output portion of the vibrational response. The haptic actuator also includes a tuning feature incorporated with the wall and configured to reduce the first component of the vibrational response while substantially maintaining the haptic output portion of the vibrational response.

FIELD

Embodiments described herein relate to haptic actuators, and in particular, to haptic actuators that may be incorporated into an electronic device to provide haptic output to a user.

BACKGROUND

An electronic device can include a mechanical actuator to generate tactile sensations for a user, generally referred to as “haptic output.” Haptic outputs can inform the user of a specific mode, operation, or state of the electronic device, or for any other suitable purpose. Some haptic actuators include masses that are oscillated, rotated, or otherwise moved to produce a haptic output. The movement of a mass when producing a haptic output may also produce an audible output, such as a buzzing.

SUMMARY

An electronic device includes an enclosure, a display positioned with the enclosure and defining a front face of the electronic device, and a haptic actuator positioned within the enclosure. The haptic actuator includes a housing comprising a wall, a movable mass positioned within the housing and configured to move within the housing to cause the haptic actuator to produce a vibrational response. The vibrational response includes a first component within a frequency range, and a second component outside of the frequency range and providing a haptic output portion of the vibrational response. The frequency range may be from about 1 kHz to about 5 kHz, and the second component of the vibrational response may be below about 1 kHz. The haptic actuator also includes a tuning feature incorporated with the wall and configured to reduce the first component of the vibrational response while substantially maintaining the haptic output portion of the vibrational response. The movable mass may be movably coupled to the housing via an elastic member, and the movable mass may be configured to move substantially linearly along a direction that is substantially parallel to the wall.

The tuning feature may be configured to reduce the first component of the vibrational response by about 10 dBA as compared to a haptic actuator without the tuning feature. The tuning feature may be a recess in an exterior surface of the wall of the haptic actuator. The wall may have a thickness between about 100 and about 500 microns, and the recess may have a depth between about 5 and about 10 microns.

A haptic actuator includes a housing comprising a wall and a movable mass positioned within the housing and configured to move relative to the housing to impart a force on the housing, thereby causing the haptic actuator to produce a haptic output that is part of a vibrational response of the haptic actuator. The actuator may further include a recess formed in the wall and configured to reduce an amplitude of a subset of frequencies present in the vibrational response while substantially maintaining the haptic output. The subset of frequencies may be between about 1.2 kHz and about 4.5 kHz. A first surface of the wall may face the movable mass, and the recess may be laser etched into a second surface of the wall that is opposite the first surface.

The recess may be formed in an exterior surface of the wall. The wall may define at least two additional recesses. The recess may include a first portion extending along a first direction and a second portion extending along a second direction different than the first direction.

An electronic device includes an enclosure, a display positioned with the enclosure and defining a front face of the electronic device, and a haptic actuator attached to an internal structure of the electronic device and configured to produce a vibrational response including at least an audible first component within a frequency range and a haptic second component outside of the frequency range. The haptic actuator includes a movable mass and a housing at least partially enclosing the movable mass and comprising a tuning feature configured to attenuate the audible first component of the vibrational response. The tuning feature may be configured to reduce the audible first component of the vibrational response without substantially reducing the haptic second component of the vibrational response. The audible first component may correspond to a frequency range of the vibrational response between about 1 kHz and below about 5 kHz, and the haptic second component may correspond to at least part of the vibrational response outside the audible first component.

The housing may include a wall defining an exterior surface of the housing, and the tuning feature may include a protrusion extending from the exterior surface.

The housing may include a wall defining an exterior surface of the housing, and the tuning feature may include a plate secured to the exterior surface. The plate may include or be formed from metal, and the plate may be secured to the exterior surface with an adhesive layer between the plate and the surface.

The housing may include a wall defining an exterior surface of the housing, the tuning feature may include a recess in the exterior surface, and the electronic device may further include a layer between and in contact with the exterior surface and the internal structure.

DETAILED DESCRIPTION

The embodiments herein are generally directed to haptic actuators for use in electronic devices. Haptic actuators are used to produce haptic outputs, which are tactilely perceptible outputs that may be felt by a user and that may convey information to the user. For example, devices with touch screens may use haptic outputs to indicate when a user has selected (e.g., touched or pressed) an affordance on the touch screen. As another example, in devices with buttons or other input regions that do not move or do not produce tactile outputs, haptic outputs may be used to provide physical feedback indicating that the device has detected an actuation of the button or other input region. As yet another example, haptic outputs may be used to notify a user of an incoming call or message, to replace or accompany a more traditional audible notification such as a ringtone.

In some cases, haptic outputs are produced by moving a mass inside the electronic device. For example, linear actuators may move a mass along a substantially linear path, and rotary actuators or motors may spin an eccentric mass about an axis. When the mass moves, the momentum of the mass imparts forces to the electronic device that produce the haptic output (e.g., the physically or tactilely detectable output). The haptic output, however, is only one part of the overall vibrational response or output of the haptic actuator. For example, the movement of the mass may also produce audible output as a result of the resonance of the structure of the actuator itself. Thus, for example, a haptic actuator that oscillates a mass at about 150 Hz may produce a vibrational response that includes a wide range of frequency components. As used herein, a vibrational response refers to or includes mechanical waves within a medium, and may include infrasonic, audible, and ultrasonic frequencies.

In some cases, the overall vibrational response that is produced when a haptic actuator is activated (e.g., to produce a haptic output) includes undesirable sound. For example, the presence of audible noise during haptic outputs may be perceived as superfluous or annoying, as the haptic actuator may be intended to primarily provide tactile feedback, not audible feedback. For example, when a haptic output is being used to simulate a collapsing key or button (e.g., a click), a higher pitched buzz, tone, or sound accompanying the tactile output may be undesirable. As another example, in some cases, a haptic actuator is intended to be used as an alternative to audible alerts, such as to discreetly notify a user of an incoming call or email (e.g., in the case of a haptic actuator in a handheld electronic device such as a smartphone). In such cases, any resonance of the haptic actuator that results in audible output may be in conflict with the purpose of the haptic output.

Accordingly, haptic actuators as described herein may include tuning features that are configured to reduce an audible portion of a vibrational response of a haptic actuator. For example, tuning features may selectively reduce the volume of sound in a particular range of frequencies within the overall vibrational response, such as frequencies to which human hearing is particularly sensitive. These frequencies may be targeted because the increased sensitivity may cause them to be more irritating to users than other frequencies, and because small changes in the amplitude of these sounds may make a more significant difference in the perceived volume of the sounds than changes to other frequencies. Thus, configuring tuning features to reduce the audible output in a range of frequencies to which human hearing is particularly sensitive (e.g., between about 1 kHz and about 5 kHz) may help maximize the perceived reduction in volume, as compared to tuning features that are configured to reduce the volume of sound in a range of frequencies to which human hearing is less sensitive.

While it may be desirable to reduce part of the audible component of the vibrational response of the haptic actuator, it may likewise be desirable to minimize or avoid changes to other portions of the vibrational response (e.g., other frequencies outside of a particular audible range), many of which may define or contribute to the overall haptic output that is perceived by a user. For example, the overall harmonic response of the actuator, including spectral content at many different frequencies, may define what a user actually feels during a haptic output. Tuning features may therefore be configured to reduce undesirable audible content (e.g., within a particular range of frequencies), without substantially altering other portions of the vibrational response (e.g., frequencies outside the particular range and that may contribute to the overall tactile feeling of a haptic output). Accordingly, a desired haptic output can be maintained while reducing or eliminating unwanted noise.

As described herein, tuning features may be formed in, on, or otherwise incorporated with a haptic actuator. Example tuning features include recesses formed into a housing of the actuator, protrusions formed on the housing, components affixed to the housing, and the like. The tuning features may alter the structure of the housing in a way that changes how mechanical waves propagate or resonate within the material of the housing. More particularly, the tuning features may reduce the extent to which the movement of a mass results in the production of audible outputs within a particular frequency range. Examples of tuning features and their particular effect on the vibrational response of a haptic actuator are described herein.

FIG. 1Adepicts an electronic device100that may use a haptic actuator to produce haptic outputs. The electronic device100is depicted as a mobile phone (e.g., a smartphone), though this is merely one example electronic device that may incorporate a haptic actuator as described herein. Accordingly, the concepts discussed herein may apply equally or by analogy to other electronic devices, including wearable electronic devices (e.g., watches, fitness trackers, biometric sensors), tablet computers, notebook computers, head-mounted displays, digital media players (e.g., mp3 players), implantable electronic devices, or the like.

The electronic device100includes an enclosure102and a cover104, such as a glass, plastic, ceramic, or other substantially transparent material, component, or assembly, attached to the enclosure102. The enclosure102may include a back and sides that cooperate to at least partially define an interior volume of the device100.

The cover104may cover or otherwise overlie a display and/or a touch sensitive surface (e.g., a touchscreen), and may define a front face and an input surface110of the electronic device100. For example, a user may operate the device100by touching the input surface110to select affordances displayed on the display. The electronic device100may also include a button106. The button106may be movable, such as a mechanical push-button or key, or it may be substantially rigid. In either case, the button106may be used to control an operation of the device100or otherwise cause the device100to perform various functions.

The electronic device100may also include a haptic actuator108positioned within the enclosure102. The haptic actuator108may produce haptic outputs that are perceived by a user of the device100. For example, the haptic actuator108may provide tactile feedback in response to inputs detected on the input surface110(e.g., touches or presses applied to the input surface110) and/or the button106(e.g., where the button106is rigid or does not otherwise provide tactile feedback). The haptic actuator108may also produce haptic outputs for other reasons, such as for notifying a user of an incoming call, email, text message, or for any other notification.

As noted above, when the haptic actuator108is actuated, the haptic actuator108may produce a vibrational response that includes a haptic component or portion that is transmitted to the user via the input surface110or the button106(or any other surface or aspect of the enclosure102or device100). This same vibrational response may also include frequencies that may not significantly contribute to the tactile sensation perceived by a user, and may in fact be distracting, irritating, or an otherwise undesirable aspect of a haptic output. Accordingly, the haptic actuator108may include tuning features that reduce these audible frequencies of the vibrational response when the haptic actuator108is used to produce haptic outputs via the input surface110, the button106, or any other portion of the device100.

FIG. 1Bis an exploded view of the device100ofFIG. 1A, showing the cover104and the haptic actuator108removed from the enclosure102. For clarity,FIG. 1Bdoes not show other components that may be present in the device100, such as processors, batteries, circuit boards, sensors, cameras, switches, memory devices, and the like. Nevertheless, it will be understood that such components, as well as others not listed, may be included in an electronic device as described herein.

The haptic actuator108may include a housing109(or other structural component) and a movable mass. The movable mass (examples of which are described herein with respect toFIGS. 8A-9) may be moved within or relative to the housing109to produce haptic outputs. For example, the haptic actuator108may produce haptic outputs by moving a mass within the housing109substantially linearly or substantially along a single plane, according to any suitable oscillating or pulsing motion, or any other suitable motion or pattern. In another example, the haptic actuator108may be configured to rotate an eccentric (e.g., unbalanced) mass about an axis at one or more speeds to produce vibrations or oscillations.

The housing109of the haptic actuator108may include mounting features115for attaching the haptic actuator108to the enclosure102. The enclosure102(or any other component or structure of the device100) may include complementary mounting features114to which the mounting features115may be attached. As shown, the mounting features115are tabs with holes that may receive a fastener therethrough. The fastener may be anchored in the mounting features114of the enclosure102to secure the actuator108to the enclosure102. Any suitable fastener may be used, such as a threaded fastener (e.g., a bolt, screw, etc.), post, clip, rivet, or the like. In some cases, a mounting feature114of the enclosure102may include a rod, shaft, or other protruding feature that is received in a hole of a mounting feature115of the haptic actuator108. The rod, shaft, or other protruding feature may then be deformed to form a rivet-like head that overlaps the mounting feature115and secures the haptic actuator108to the enclosure102(or to any component to which the haptic actuator108is attached).

The haptic actuator108may impart forces onto the device100via the mounting features114,115, or via any other areas of physical contact between the haptic actuator108and the device100. For example, when a mass inside the housing109is moved to produce a haptic output, momentum from the moving mass may be transmitted to the enclosure102via the mounting features114,115. In some cases, a wall or surface of the housing109may be in contact with an underlying surface of the enclosure102(or another component of the device100), and the momentum from the haptic actuator108may be transmitted through the contacting surfaces. In other cases, there may be one or more layers of material between the housing109and the underlying surface of the enclosure102(or other internal component of the device100), such as an adhesive, shim, foam pad, or the like. In such cases, the momentum from the haptic actuator108may be transmitted to the underlying surface or component (and ultimately to the enclosure102) through the interstitial layer(s). In addition to the momentum from the moving mass, an entire vibrational response of the haptic actuator, including higher frequency content produced by the actuator108, may be transmitted to the enclosure102via the mounting features and/or contacting surfaces between the actuator108and the enclosure102.

The haptic actuator108may be electrically connected to other components of the device100to facilitate the operation of the haptic actuator108. For example, the haptic actuator108may be connected to a power source (e.g., a battery) and a controller that controls various aspects of the haptic actuator108, such as a speed, frequency, or pattern of motion of a mass of the haptic actuator108. More particularly, a controller may control how and when electrical current is applied to electrical coils, piezoelectric materials, or other components configured to move a mass, to produce a desired haptic output. Example haptic outputs that may be produced by the haptic actuator108in conjunction with the controller and power source include oscillations, vibrations, pulses (e.g., non-repeating or non-cyclical movements of a mass), or the like.

FIG. 2Ais a schematic representation of a haptic actuator200. The haptic actuator200includes a housing or frame204, and a mass202that is movable relative to the housing or frame204. While the movement of the mass202relative to the housing or frame204is represented inFIG. 2Aas a linear movement, this is merely for representation and a mass may move in any suitable manner to produce haptic outputs, such as by rotating.

FIG. 2Bdepicts an example volume vs. frequency plot206of a vibrational response of a representative haptic actuator (e.g., the haptic actuator200) while the haptic actuator is producing a haptic output. The volume axis of the plot206may represent a weighted or scaled representation of the volume of a sound produced by a haptic actuator. For example, the volume axis may represent an A-weighted volume of the sound, which scales the volume to account for the different sensitivity of human hearing to different frequencies. For example, human hearing has different sensitivities to sounds of different frequencies such that frequencies having equivalent sound pressure levels are not necessarily perceived as having equivalent volumes. Accordingly, the plot206(and in particular the volume axis) may be scaled to more accurately represent the perceived volume of certain frequencies.

The frequency axis of the plot206may illustrate the frequencies that may be present in a given vibrational response of a haptic actuator. As noted above, the vibrational response of a haptic actuator may include vibrational content (e.g., mechanical waves) at numerous different frequencies, which may include any frequencies including infrasonic, audible, and ultrasonic frequencies. The spectral content of a vibrational response may be the result of various mechanical properties of the haptic actuator itself, as well as other components, objects, fluids, or other materials in contact with or in proximity to the haptic actuator. For example, a mass (e.g., the mass202) within a haptic actuator (e.g., the haptic actuator200) may be moved or oscillated at a particular frequency (e.g., 150 Hz). Due to the mechanical properties of the actuator and the surrounding environment, the vibrational response of the actuator includes numerous additional frequencies, such as harmonics or overtones of the original oscillation frequency, as well as other frequencies that may be caused by friction between components of the actuator, resonance of the physical structures of the actuator, as well as other phenomena.

Many of the spectral components of the vibrational response of an actuator may contribute to the tactile feel of a haptic output. These spectral components may include a portion of the vibrational response that is at a frequency of oscillation or rotation of a mass of a haptic actuator, as well as other physically perceptible frequency components.

A portion of the vibrational response may also be within a particular range of audible frequencies that are aurally undesirable. This component or portion of the vibrational response, represented inFIG. 2Bby the range208, may refer to a frequency range to which human hearing is particularly sensitive. For example, the range208of the vibrational response shown inFIG. 2Bmay be between about 1 kHz and about 5 kHz, or between about 1.2 kHz and about 4.5 kHz (or any other narrower included range). While other portions of the vibrational response may be audible, the increased sensitivity of human hearing to the frequencies in this particular range may cause this portion of the vibrational response be perceived as particularly loud. Further, such sounds may be irritating or convey an impression of a low-quality or broken component or device.

As noted above, in order to reduce the volume of a haptic output, the haptic actuator may include a tuning feature that is configured to reduce the volume of a subset of the frequencies in the vibrational response. For example, the tuning feature (or tuning features) may attenuate or reduce a portion of the vibrational response that is between about 1 kHz and about 5 kHz, where human hearing is particularly sensitive. The tuning feature may also be configured so that it does not substantially reduce other frequencies or components of the vibrational response, such as frequencies that are outside of the targeted portion of the vibrational response (e.g., frequencies that are below about 1 kHz or above about 5 kHz). Accordingly, the tuning feature can act as a notch filter or a band-stop filter for the vibrational response, reducing unwanted audible output and maintaining other frequencies so that the overall haptic output remains substantially unchanged.

FIG. 3Adepicts an example haptic actuator300with a tuning feature302, which may be configured to reduce a subset of the audible frequencies of the vibrational response of the haptic actuator300. The tuning feature302may be any suitable feature, such as a recess, protrusion, plate, hole, pattern, or the like. The tuning feature302may change the mechanical properties of a housing301of the actuator300so that audible output within a particular frequency band is attenuated. The tuning feature302may change the stiffness or rigidity (or any other suitable property) of the housing301, and thus may change how mechanical waves propagate and/or resonate through the material of the housing301. For example, the tuning feature302may change a resonant frequency of the housing301.

FIG. 3Bdepicts an example volume vs. frequency plot304of a vibrational response of the haptic actuator300while the haptic actuator300is producing a haptic output. Like the plot inFIG. 2B, the volume axis of the plot inFIG. 3Bmay represent a weighted or scaled representation of the volume of a sound produced by the haptic actuator, such as an A-weighted volume of the sound produced by a haptic actuator. However, the plot304includes an attenuated output in the component of the vibrational response within the range208. In particular, the A-weighted volume of the frequencies in the range208may be reduced, while the A-weighted volume (as well as other properties or values) of the other components of the vibrational output (e.g., outside the range208) are substantially unchanged. For example, the vibrational response of the actuator300outside of the 1 kHz to 5 kHz range may be substantially unchanged as compared to an actuator without the tuning feature. In some cases, the tuning feature302reduces the volume of the frequencies within the range208by about 10 dBA (A-weighted decibels) as compared to a haptic actuator without the tuning feature. In some cases, the volume is reduced by about 8 dBA, 9 dBA, 11 dBA, 12 dBA, or any other suitable value. In some cases, the frequencies of the vibrational response outside of the range208may be attenuated by less than about 0.5 dBA, 1 dBA, 2 dBA, or 5 dBA (individually and/or on average), despite the presence of the tuning feature and the attenuation of the targeted frequency range.

A haptic actuator with a tuning feature that reduces the amplitude of frequencies within a particular frequency range results in an actuator that is quieter but that still produces haptic outputs with substantially the same tactile feel. This may be particularly useful when a desired haptic output from a haptic actuator produces too much noise in a particular frequency band, as the tuning feature can reduce the unwanted noise without substantially changing the tactile feel of the desired haptic output.

The tuning feature302is shown as a zig-zag or “N” shaped feature (e.g., a protrusion or recess) on a surface of the housing of the haptic actuator300. However, this configuration is representative of any suitable tuning feature that may produce the attenuation of the targeted frequencies of the vibrational response. Other examples of tuning features that may produce the attenuation represented inFIG. 3Bare described herein with respect toFIGS. 4A-7B and 9.

FIG. 4Adepicts an example haptic actuator (or simply “actuator”)400that includes a tuning feature. In particular, the actuator400includes a housing403having a first exterior surface401and a second exterior surface404. The actuator400may be configured to be installed in a device such that that the second exterior surface404is facing or is in contact with an internal structure or component of the device (e.g., a circuit board, enclosure, battery, mounting layer, or other component inside an electronic device). The second exterior surface404may be in contact with another component, or it may be separated from another component by a gap (e.g., an air gap). Where the second exterior surface404is in contact with another component, mechanical waves or vibrations may propagate from the housing403to the other component via the interface between the second exterior surface404and the other component. In this way, the component in contact with the housing403(as well as other components to which mechanical waves may propagate from the housing403) may amplify or transmit portions of the vibrational response, which may make the component of the vibrational response within a range of high human sensitivity more prominent. Accordingly, positioning the tuning feature on this surface may aid in reducing the overall audible output of the haptic actuator as perceived by a user of the device.

FIG. 4Bdepicts the second exterior surface404(also referred to as a bottom surface) of the haptic actuator400, andFIG. 4Cdepicts a partial cross-sectional view of the actuator400viewed along line A-A inFIG. 4B(with internal components such as a movable mass omitted for clarity). As shown inFIGS. 4B-4C, the bottom surface404of the actuator400(e.g., the exterior surface of a bottom wall405) includes tuning features402(including tuning features402-1, . . . ,402-n). The tuning features402are channels or recesses formed into the bottom surface404and having a zig-zag or “N” shaped pattern. For example, the channels may have a first portion (e.g., corresponding to one leg of the “N” shaped pattern) extending along one direction, and a second portion (e.g., corresponding to a second leg of the “N” shaped pattern) extending along a different direction than the first portion. As shown inFIG. 4B, there are three discrete tuning features402. In some cases, a single, continuous channel or recess having a zig-zag pattern (e.g., including several linear portions extending along different directions) may be used.

The pattern and positioning of the tuning features402may be configured to disrupt the propagation, resonance, and/or amplification of certain mechanical waves within the housing403, and in particular within the bottom surface404. For example, the positioning of the three tuning features402-1,402-2, and402-3at even intervals along a longitudinal axis of the housing403may provide a desired attenuation of a particular frequency band. The tuning features402may cause the attenuation by changing the stiffness of the housing, by increasing the resistance to the propagation of mechanical waves or vibrations through the housing material, or via other phenomena. For example, the discontinuities in the surface of the bottom wall405may impede mechanical waves within the material, making it more difficult for the waves (e.g., vibrations) within a particular frequency band to propagate or resonate in the material. The discontinuities may also change a fundamental frequency of the housing403(or the bottom wall405), resulting in a different vibrational response during a haptic output as compared to a housing without the tuning features.

FIG. 4Dshows a portion of the actuator400corresponding to detail B-B inFIG. 4C, showing details of recesses406-1,406-2of a tuning feature402. Like the zig-zag pattern of the tuning feature402, the shape and dimensions of the recesses406may also contribute to the effectiveness of the tuning feature402in reducing the volume of certain audible frequencies. For example, in some cases, the recesses406have a depth408that is between about 1 and about 50 microns, or between about 5 and about 20 microns, or between about 5 and about 10 microns. In a wall405having a thickness410that is between about 100 and about 500 microns, the recesses406having a depth within these ranges may produce a desired attenuation (e.g., an attenuation of about 8-12 dBA in a frequency range between about 1-5 kHz or about 1.2-4.5 kHz), and may attenuate other frequencies less than about 5 dBA. The recesses406may have a width416(FIG. 4D) between about 100 microns and 2.0 mm.

The tuning features402may be formed by any suitable technique. For example, the tuning features402may be formed by machining, laser etching, chemical etching, plasma etching, or any other suitable technique. In a laser etching process, a laser may be used to form a recess (e.g., a channel) having a particular width. For example, the laser may produce a beam having a particular spot size (corresponding to the desired width), which may be directed on the wall405and pulsed as the beam is translated along the path of the recess. The process of translating the beam while pulsing the beam ablates material from the wall405to form the recess. Further, the channel produced by the laser etching process may be defined by opposing sidewalls that have a scalloped shape. For example,FIG. 4Eshows a portion of the actuator400corresponding to detail E-E inFIG. 4B. The recess406(corresponding to the tuning feature402-1) has opposing sidewalls412, each having a scalloped surface. In particular, the sidewalls412may include or be defined by rounded segments414that may be artifacts of the size and shape of the laser beam (which may be substantially circular) as the beam is pulsed to ablate the material and form the recess402-1.

FIGS. 4A-4Dshow tuning features that are recesses in a wall of the housing. In other cases, tuning features may be protrusions instead of recesses.FIGS. 5A-5D, discussed below, depict an example haptic actuator500having tuning features502that are or include protrusions or protruding structures.

FIG. 5Adepicts an example haptic actuator (or simply “actuator”)500that includes a housing503having a first exterior surface501and a second exterior surface504. Similar to the actuator400, the actuator500may be configured to be installed in a device such that the second exterior surface504is facing or in contact with an internal structure or component of the device (e.g., a circuit board, enclosure, battery, mounting layer, or other component inside an electronic device). Mechanical waves may propagate from the housing503to another component of a device as described above with respect toFIG. 4A.

FIG. 5Bdepicts the second exterior surface504(also referred to as a bottom surface) of the haptic actuator500, andFIG. 5Cdepicts a partial cross-sectional view of the actuator500viewed along line C-C inFIG. 5B(with internal components such as a movable mass omitted for clarity). As shown inFIGS. 5B-5C, the bottom surface504of the actuator500(e.g., the exterior surface of a bottom wall505) includes tuning features502(including tuning features502-1, . . . ,502-n). The tuning features502are protrusions formed on the bottom surface504and having a zig-zag or “N” shaped pattern. As shown inFIG. 5B, the actuator500includes three discrete tuning features502. In some cases, a single, continuous protrusion or rib having a zig-zag pattern may be used.

The tuning features502may function in substantially the same way as the tuning feature402. For example, the pattern and positioning of the tuning features502may be configured to disrupt the propagation, resonance, and/or amplification of certain mechanical waves or vibrations within the housing503, and in particular within the bottom surface504. For example, the positioning of the three tuning features502-1,502-2, and502-3at even intervals along a longitudinal axis of the housing503may provide a desired attenuation of a particular frequency band within the vibrational response of the actuator500, without substantially attenuating other frequencies. The tuning features502may cause the attenuation by changing the stiffness of the housing, by increasing the resistance to the propagation of mechanical waves or vibrations through the housing material, or via other phenomena. For example, the discontinuities in the surface of the bottom wall505may impede mechanical waves within the material, making it more difficult for mechanical waves within a particular frequency band to propagate or resonate in the material. The discontinuities may also change a fundamental frequency of the housing503(or the bottom wall505), resulting in a vibrational response having a different vibrational response during a haptic output as compared to a housing without the tuning features.

FIG. 5Dshows a portion of the actuator500corresponding to detail D-D inFIG. 5C, showing details of protrusions506-1,506-2of a tuning feature502. Instead of the recesses of the tuning features402, the tuning features502include protrusions506, such as raised wall features. The protrusions may have any suitable height508above a base surface of the bottom wall505, such as between about 10 and about 100 microns, while the wall505may have a thickness510that is between about 100 and about 500 microns.

The protrusions506may be formed in any suitable way. For example, the protrusions506may be formed by machining or etching (e.g., laser, plasma, or chemical etching) material from the wall505to produce the protrusions506and a base surface that is relieved relative to the protrusions506. Alternatively, the protrusions506may be formed by physical vapor deposition, chemical vapor deposition, welding, additive manufacturing, or any other suitable technique.

FIGS. 6A-6Edepict additional example tuning features that may be used to selectively reduce a component of a vibrational response within a particular frequency band or range. Any of the tuning features shown and described with respect toFIGS. 6A-6Emay be formed as recesses (similar to the tuning features402described with respect toFIGS. 4A-4D) or protrusions (similar to the tuning features502described with respect toFIGS. 5A-5D), and may have similar dimensions and may be formed in similar manners to the tuning features402,502.

FIG. 6Adepicts an actuator600with a single, serpentine tuning feature602. The tuning feature602may be a single, continuous feature that extends over substantially an entire surface of the actuator600(e.g., substantially edge-to-edge).

FIG. 6Bdepicts an actuator610with a series of substantially parallel, linear tuning features612. As shown, the tuning features612may extend along a direction that is perpendicular to a longitudinal axis (e.g., left-to-right as shown inFIG. 6B) of the actuator610. In cases where the actuator610is a linear actuator, the tuning features612may each extend substantially perpendicularly to an axis or direction of motion of a mass that is positioned within the actuator610. In some cases, the tuning features612may be oriented at an oblique angle relative to a longitudinal axis (or an axis or direction of motion of a mass), such as about 10, 20, 30, 45, or 60 degrees from the longitudinal axis. WhileFIG. 6Bshows ten separate parallel tuning features612, any number of tuning features612may be used, and they may be spaced apart in any suitable configuration. For example, the tuning features612may be evenly spaced (as shown), or they may be separated into multiple groups with each group having a first spacing between features and each group being spaced apart from an adjacent group by a second different spacing. Alternatively, the tuning features may be spaced differently, such as with irregular spacing.

FIG. 6Cdepicts an actuator620with three x-shaped tuning features622-1,622-2, and622-3. The x-shaped tuning features may include a first portion (e.g., corresponding to one leg of the x-shaped pattern) extending along one direction, and a second portion (e.g., corresponding to a second leg of the x-shaped pattern) extending along a different direction than the first portion. The tuning features622may be positioned substantially in-line along a longitudinal axis of the actuator620. As shown, the tuning features622are physically separate features, though in other cases they may be a single continuous feature (e.g., the terminal ends of adjacent legs of adjacent features may be joined to form a continuous channel or rib).

FIG. 6Ddepicts an actuator630with three tuning features632-1,632-2, and632-3each having a zig-zag shape. The tuning features632are shown rotated 90 degrees as compared to the tuning features402,502. More particularly, the zig-zag shaped tuning features632are shown extending along an axis that is substantially perpendicular (e.g., 90 degrees) to the longitudinal axis of the actuator630. In other examples, the tuning features may be oriented along a different angle relative to the longitudinal axis, such as 60, 45, or 30 degrees, or any other suitable angle. As shown, the tuning features632are separated from one another by a space634. This space may be any suitable size or dimension. For example, the space may be about 1, 2, or 3 times the width of the tuning features themselves. In other cases, the space may be less than a width of a tuning feature. The particular dimensions of the tuning feature and the space between adjacent tuning features may be selected to produce a desired attenuation of mechanical waves within the housing of the actuator630(e.g., to attenuate frequencies between about 1 kHz and about 5 kHz).

FIG. 6Edepicts an actuator640with tuning features642-1,642-2, and642-3, each composed of a group of recesses, through-holes, or protrusions (e.g., posts, bosses, or the like). The recesses or protrusions of the features642are arranged in a regular pattern or array (e.g., a grid), though other shapes and arrangements of the recesses or protrusions are also contemplated (e.g., recesses or protrusions arranged to form circles, x-shapes, zig-zags, squares, or the like).

While the tuning features described above are shown on a bottom exterior surface of a housing, they may also or instead be positioned on other surfaces or portions of an actuator housing. For example, they may be positioned on an inward or interior facing surface of the bottom wall of an actuator housing. Additionally or alternatively, they may be positioned on an exterior or interior surface of a top wall or side of the actuator housing. In some actuator configurations, they may be positioned on other components or portions of the actuator, such that the vibrational response is attenuated within a particular range of audible frequencies, without substantially attenuating other frequencies.

FIGS. 7A-7Bdepict perspective and partial cross-sectional views, respectively, of a haptic actuator700having a tuning feature702in the form of a plate706(FIG. 7B) that is secured to a housing703of the actuator700. The tuning feature702may function to attenuate or reduce the volume of frequencies within a particular band, similar to the tuning features described above with respect toFIGS. 4A-6E. For example, the tuning feature702may add mass to the actuator700, which may change a fundamental frequency of the housing703(or a wall of the housing703) and thus may selectively reduce the volume of a portion of the vibrational response of the actuator700within a particular frequency range.

The tuning feature702may include a plate706. The plate706may be formed of any suitable material, such as plastic, metal, glass, ceramic, or the like. The plate706may be configured to have a particular physical property, such as stiffness, density, mass, outer dimension, or the like, to have a desired effect on the vibrational response of the actuator700. For example, the mass of the plate706may be selected such that the vibrational response of the actuator700is attenuated within a particular frequency band (e.g., between about 1 kHz and about 5 kHz or any range therein) as compared to the actuator without the plate706. In some embodiments, the plate706may be formed from steel, aluminum, tungsten, copper, or the like. Where the plate706is conductive, it may also form a shield that reduces electromagnetic interference from or to the actuator700.

The plate706may be positioned on any surface of the actuator700. As shown, the actuator700includes a first (e.g., a top) surface701and a second (e.g., bottom) surface704that is opposite the first surface701. As shown inFIGS. 7A-7B, the plate706is positioned on the first surface701, though this is merely one example configuration, and the plate may be positioned on the second surface704. In some cases, multiple plates are used, with one or more plates on each of the first and second surfaces701,704(and optionally one or more plates on any of the side surfaces of the actuator700).

In some cases, when the actuator700is incorporated in an electronic device (e.g., a smart phone), the plate706is in contact with another component or structure of the device, such as a circuit board, a battery, a mounting feature of an enclosure of the device, a display component, or the like. Also, the plate706may be arranged in a device such that, when the device is dismantled (e.g., for repair), the plate706is visible without removal of the actuator700from the device. In such cases, the plate706may include readable information, such as a serial number, logo, device name, or any other suitable information. When readable information is included on the plate706, it may be applied or incorporated in any suitable way, such as via engraving, etching, ink or paint deposition, anodizing, additional labels, or the like.

The plate706may be attached to the housing703via an adhesive layer705. The adhesive layer705may be any suitable adhesive, such as a pressure or heat sensitive adhesive, epoxy, cyanoacrylate, or the like. The physical properties (e.g., stiffness, elasticity, bond strength, thickness, application pattern, etc.) of the adhesive layer705may be configured or selected to further improve attenuation of frequencies within a desired frequency band. In some cases, however, the adhesive layer705may be substantially inconsequential to the performance of the plate706as a tuning feature. For example, the adhesive layer705may be sufficiently thin that the effect of the adhesive layer705on the vibrational response of the actuator700may be negligible. Instead of or in addition to an adhesive layer, the plate706may be attached by welding, soldering, brazing, or any other suitable process or component.

FIGS. 8A and 8Bdepict partial cut-away views of example haptic actuators, showing several example arrangements of movable masses and elastic members that movably couple the masses to the housing. For example,FIG. 8Adepicts a haptic actuator800that includes a housing802, with a movable mass804movably coupled within the interior of the housing802via elastic members806. The elastic members806are configured as a substantially flat (e.g., ribbon shaped) spring that is formed into a curved or bent configuration. The elastic members806deflect or deform when the mass804is moved within the housing802(e.g., along a direction of motion807), and, when deflected or deformed, they impart a force to the mass804to return the mass804to a central or neutral position.

Similarly,FIG. 8Bdepicts a haptic actuator810that includes a housing802, with a movable mass814movably coupled within the interior of the housing812via elastic members816. In the example actuator810, the elastic members are coil springs that deflect or deform when the mass814is moved within the housing812(e.g., along a direction of motion817).

The haptic actuators800,810inFIGS. 8A-8Bmay also include other components and features, such as electrical coils, magnets, structural guides and/or supports, and the like. Structural guides and/or supports may help support the masses relative to the housing and may guide the masses so that they move substantially along a linear direction or substantially within a particular plane. Coils, magnets, and the like may be used to cause the masses to move relative to the housings, for example, by selectively energizing coils to produce a motive force on the masses. The motion of the masses804,814, including the forces applied to the housing via the elastic members806,816, friction between the masses and support members, resonance of the elastic members, etc., may contribute to the overall vibrational response of the haptic actuator, and thus may ultimately produce undesirable audible output. The haptic actuators800,810may therefore use tuning features such as those described above to reduce or attenuate a portion of the vibrational response having particular audible content.

FIG. 9depicts an example rotary haptic actuator900that may include one or more tuning features that are configured to reduce or attenuate a subset of the frequencies in a vibrational response of the haptic actuator900. The haptic actuator900may include a housing902and an eccentric (e.g., unbalanced) mass906coupled to a shaft of the haptic actuator900. The housing902may enclose or be a functional part of a motor that causes the eccentric mass906to spin relative to the housing902. The motor may be any suitable motor, such as a brushed direct-current motor, a brushless motor, a servo, a piezoelectric motor, or the like.

The haptic actuator900may be configured to rotate the eccentric mass906to cause a vibration that may be transferred to another component or device via mounting features904. For example, the haptic actuator900may be coupled to an electronic device (e.g., a battery, enclosure, circuit board, or other component of an electronic device), and when the eccentric mass906is rotated, the vibrations may be transmitted to the electronic device to produce a haptic output.

When rotating to produce a haptic output, the haptic actuator900may produce a vibrational response. Like the linear haptic actuators described above, the overall vibrational response may be a result of the force impulses produced by the rotation of the eccentric mass906, friction from bearings or bushings or other contacting parts, harmonics of the overall actuator structure, or the like. Without tuning features, the vibrational response of the haptic actuator900may be correspond to a volume vs. frequency plot such as that shown inFIG. 2B. For example, the vibrational response may include a component within a frequency range to which human hearing is particularly sensitive. Accordingly, the haptic actuator900may include one or more tuning features908that reduce or attenuate that particular component of the vibrational response (e.g., frequencies between about 1 kHz and about 5 kHz), but that do not substantially reduce or attenuate other components of the vibrational response.

The tuning features908may be substantially similar in structure and function to those described above. For example, the tuning features908may be recesses or protrusions formed in an exterior surface of the housing902. In some cases, the tuning features908may be openings that extend through the housing902from an exterior surface of the housing to an interior surface of the housing. As yet another example, the tuning features may include multiple small recesses or through-holes that are arranged in regular patterns to form arrays (e.g., grids) or other shapes (e.g., circles, x-shapes, zig-zags, squares, or the like).

The tuning feature908of a rotating haptic actuator may operate in substantially the same way as those in a linear actuator, and may thus provide similar audible-frequency attenuation. For example, the tuning features908may reduce the amplitude or apparent volume of a subset of the frequencies of the overall vibrational response of the haptic actuator900. More particularly, they may attenuate frequencies between about 1 kHz and about 5 kHz by about 8-12 dBA. Furthermore, the tuning features908may achieve such attenuation without substantially attenuating other frequencies in the overall vibrational response (e.g., frequencies below about 1 kHz and/or above about 5 kHz). For example, frequencies outside of the targeted range may be attenuated by less than about 5 dBA, individually and/or on average.

The tuning features908may achieve such attenuation in the same or similar manner as described above in conjunction with linear actuators. For example, the tuning features908may change the fundamental frequency of the housing902, and thus change how the housing902resonates when the mass906is being rotated (e.g., when the actuator900is producing a haptic output). The tuning features908may also or instead disrupt the propagation of mechanical waves or vibrations through the material of the housing902, thus changing the extent to which certain frequencies can travel, resonate, or become amplified in the material of the housing902. Other phenomena may also contribute to the particular effect of the tuning features908on haptic outputs.

The foregoing description, for purposes of explanation, used specific nomenclature to provide a thorough understanding of the described embodiments. However, it will be apparent to one skilled in the art that the specific details are not required in order to practice the described embodiments. Thus, the foregoing descriptions of the specific embodiments described herein are presented for purposes of illustration and description. They are not targeted to be exhaustive or to limit the embodiments to the precise forms disclosed. It will be apparent to one of ordinary skill in the art that many modifications and variations are possible in view of the above teachings. For example, while the methods or processes disclosed herein have been described and shown with reference to particular operations performed in a particular order, these operations may be combined, sub-divided, or re-ordered to form equivalent methods or processes without departing from the teachings of the present disclosure. Moreover, structures, features, components, materials, steps, processes, or the like, that are described herein with respect to one embodiment may be omitted from that embodiment or incorporated into other embodiments.