Abstract:
An apparatus for providing haptic feedback, including: a shell defining an aperture; a driver disposed within the shell; a mass disposed within the coil; and a projection connected to the mass and extending through the aperture. Also described herein is a method for providing generalized and localized haptic feedback, including the operations of: receiving an input signal; determining if the input signal corresponds to a generalized haptic feedback; if so, providing a first input to a linear vibrator; otherwise, providing a second input to a linear vibrator; wherein the linear vibrator outputs a generalized haptic feedback in response to the first input; and the linear vibrator outputs a localized haptic feedback in response to the second input.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit under 35 U.S.C. §119(e) to U.S. Provisional Patent Application No. 61/449,598, filed Mar. 4, 2011 and titled “Linear Vibrator Providing Localized Haptic Feedback,” this disclosure of which is hereby incorporated herein in its entirety. 
    
    
     TECHNICAL FIELD 
     Embodiments described herein generally relate to vibration-producing devices, and more particularly to vibration-producing devices providing localized haptic feedback. 
     BACKGROUND 
     Many electronic devices use linear vibrators to provide generalized haptic feedback by shaking or vibrating the device enclosure. For example, many mobile telephones may be set to a vibrate mode, so that the phone body (e.g., enclosure) vibrates when a call is received in lieu of emitting an audible ring tone. However, linear vibrators typically vibrate the entire device and/or enclosure and thus provide generalized haptic feedback. 
     In certain embodiments, it may be useful or desirable to localize haptic feedback. For example, certain electronic devices may use virtual or touch-based keyboards, buttons, and other input mechanisms. Without some form of localized feedback, it may be difficult for a user to detect if the input mechanism was properly or adequately touched. A generalized haptic feedback, such as vibrating the entire electronic device, may be insufficiently precise. 
     SUMMARY 
     One embodiment described herein may take the form of an apparatus for providing haptic feedback, including: a shell defining an aperture; a driver disposed within the shell; a mass disposed within the coil; and a projection connected to the mass and extending through the aperture. 
     Another embodiment described herein may take the form of a method for providing generalized and localized haptic feedback, including the operations of: receiving an input signal; determining if the input signal corresponds to a generalized haptic feedback; if so, providing a first input to a linear vibrator; otherwise, providing a second input to a linear vibrator; wherein the linear vibrator outputs a generalized haptic feedback in response to the first input; and the linear vibrator outputs a localized haptic feedback in response to the second input. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         FIG. 1  is a cut-away perspective view of a simplified linear vibrator capable of providing haptic feedback. 
         FIG. 2  is a cut-away view perspective of the linear vibrator of  FIG. 1  in a sample electronic device enclosure. 
         FIG. 3A  is a cross-sectional view of the linear vibrator of  FIG. 1  in a first operational position within the enclosure of  FIG. 2 . 
         FIG. 3B  is a cross-sectional view of the linear vibrator of  FIG. 1  in a second operational position within the enclosure of  FIG. 2 . 
         FIG. 4  is a cross-sectional view of the linear vibrator of  FIG. 1  in a third operational position within the enclosure of  FIG. 2 , providing localized haptic feedback. 
         FIG. 5  is a flowchart depicting operational modes of the linear vibrator of  FIG. 1 . 
     
    
    
     DETAILED DESCRIPTION 
     One embodiment described herein may take the form of a linear vibrator capable of providing localized haptic feedback. The vibrator may include a mass and a driver operable to oscillate or otherwise move the mass. The driver and mass may be contained within a shell. A projection may extend from one end of the mass through the shell. 
     During normal operation, the driver may oscillate the mass rapidly along an axis of motion. The kinetic energy created by this oscillation may be transferred to the shell by a leaf spring or other coupling element coupling the mass and the shell. For example, any elastic element may couple the mass and shell. The shell, in turn, may be connected or affixed to a housing of an electronic device. In this manner, the housing may vibrate as the kinetic energy of the mass oscillation is transferred through the shell and to the housing, thereby providing generalized haptic feedback. 
     Further, the vibrator may be operated in a boosted mode to provide localized haptic feedback. In the boosted mode, the driver moves the mass reciprocally further along its axis of motion. The range of motion of the mass in the boosted mode is sufficient to cause the projection to impact a portion of the electronic device housing. The projection may transfer kinetic energy directly to the impacted portion of the housing. Since the projection is relatively small in relation to the size of the housing, this impact may create a vibration in a relatively small area of the housing. In certain embodiments, the vibration may be felt only in the impacted portion of the housing. In other embodiments, the vibration may be felt in some area around the impacted portion but generally not across the entirety of the housing. Thus, the embodiment may provide generalized haptic feedback when operating in a standard mode and localized haptic feedback when operating in a boosted mode. 
       FIG. 1  is a cut-away view of one sample embodiment of a linear vibrator  100 , taken approximately through the center of the embodiment. It should be appreciated that the linear vibrator  100  shown in  FIG. 1  is simplified for purposes of clarity. For example, an elastic member (such as a leaf spring) generally rests between the magnet  105  and shell  110 ; the elastic member is not shown in  FIG. 1 . Likewise, one or more pads may be placed between the inner surface of the top wall  115  and the top of the magnet to mute or muffle sounds created by the magnet impacting the shell. These pads are likewise not shown. Other elements on the linear vibrator  100  may also be omitted from  FIG. 1  for purposes of clarity, although one of skill in the art will appreciate that such elements may be present in operation or construction. 
     Generally, the linear vibrator  100  includes a shell  110 , a coil  120  disposed within the shell and adjacent the interior of the shell&#39;s sidewall(s), a mass (e.g., magnet)  105  within the coil and a tap rod  125  projecting upwardly from the magnet. “Up,” “down,” “top,” “bottom” and other such directions and/or references are used for purposes of convenience and with respect to the orientation shown in the figures, although it should be appreciated that certain embodiments may vary such directions, references and relationships described by directions and/or references, as necessary. For example, in some embodiments the tap rod  125  may project downwardly from the magnet  105  when the linear vibrator  100  is in the orientation shown in  FIG. 1 . 
     It should also be appreciated that the mass  105  need not be magnetic in and of itself. Instead, the mass  105  may be made of steel, iron or another material that reacts to magnetic fields, such that the mass may move when the coil  120  is energized. Similarly, it should be appreciated that the single coil  120  shown in the figures may be replaced with multiple coils in order to create a multi-phase actuator. 
     The tap rod  125  extends through an opening  130  in the top of the shell and is affixed to the magnet  105 . The tap rod may be made from any suitable material, including metal, ceramic, a magnetic material, composites, plastics and the like. As the magnet  105  moves, the tap rod  125  moves. 
       FIG. 2  is a cut-away view showing the linear vibrator  100  affixed to a wall  200  of the electronic device enclosure  205 . The enclosure  205  may be the body of a mobile phone, for example, or the body of a tablet computing device, personal digital assistant, laptop computer, computing peripheral or other suitable device. Typically, although not necessarily, the linear vibrator&#39;s shell is affixed to a rear wall  200  of the enclosure. In the present embodiment, neither the shell  110  nor the tap rod  125  of the vibrator abuts the enclosure  205  when the vibrator is inactive. An air gap  210  exists between the top of the tap rod and the inner surface of the upper wall  215  of the device enclosure. 
     It should be appreciated that the size, configuration and/or positioning of the shell  110  and/or tap rod  125  may vary from embodiment to embodiment. Accordingly, the setup shown in  FIG. 2  is meant merely to be illustrative of one sample embodiment. 
       FIGS. 3A and 3B  depict the linear vibrator  100  during normal operation (e.g., when generalized haptic feedback is required or requested). During normal operation, current is provided to the coil  120 . When the coil is energized, it generates a magnetic field that displaces or deflects the magnet  105 . Generally, the magnet  105  is deflected upward. When the coil  120  is de-energized, the magnet may return to its initial position. Thus, if the current is a direct current, the coil may be sequentially energized and de-energized to rapidly oscillate the magnet between the positions shown in  FIGS. 3A and 3B . It should be appreciated that the deflection shown in  FIG. 3B  results from energizing the coil  120 . When the coil is energized, the size of the air gap  210  between the tap rod and top surface of the enclosure shrinks, but typically the air gap is still present. The motion of the magnet  105  or mass may create a vibration or motion in the enclosure or associated electronic device, thereby generating a haptic feedback for a user. 
     Other embodiments may provide an alternating current to energize the coil  120 . In these embodiments, the magnet  105  may be forced upward during one phase of the alternating current and downward during the other. Accordingly, it may not be necessary to sequentially energize and de-energize the coil as with a direct current. 
       FIG. 4  depicts the linear vibrator  100  during a boosted operation, at maximum deflection. When enhanced localized haptic feedback is desired, the current provided to the linear vibrator  100  may be increased, thereby increasing the maximum deflection of the magnet  105  within the coil  120 . This, in turn, increases deflection of the tap rod  125 . In the present embodiment, the tap rod  125  is deflected sufficiently to impact the electronic device housing, thereby creating a localized feedback that may be physically perceived (for example, by a user&#39;s finger or hand). The aforementioned oscillation of the magnet  105  draws the tap rod  125  down, away from the enclosure, and then pushes the rod into the enclosure. The frequency of oscillation may be varied to create different haptic responses. 
     Certain embodiments may actuate the linear vibrator  100  in response to different input signals. Further, the vibrator  100  may be actuated in normal or boosted mode in response to different input signals. As one non-limiting example, the vibrator may be incorporated into a mobile telephone having a touch-sensitive input. When a telephone call is received and the phone is set to a silent or vibrate mode, the linear vibrator  100  may operate in the normal mode. Thus, the received call functions as an input signal to activate the vibrator. The normal mode may not only provide haptic feedback, but an audible feedback such a s a “buzz” or vibrating noise, as well. 
     Further, the vibrator  100  may be configured to be activated when a user touches a particular portion of a touch-sensitive screen of the mobile phone. When the user&#39;s touch or near-touch is sensed in the appropriate area of the screen, the vibrator may be activated in a boosted mode, thereby providing localized haptic feedback directly under the area in which the touch was sensed. In this manner, the localized haptic feedback may serve to confirm the touch to the user, for example by emulating the feeling of pressing a button. In this embodiment, the linear vibrator  100  is located under the particular portion of the touch screen in which localized haptic feedback is desired. The touch screen may be capacitive sensing, resistive sensing, or the like. In some embodiments, the button may not be depressed by a user input. Instead, the localized haptic feedback may vibrate or move the button (or button area) in such a manner that it emulates the feeling of pressing a button, for example through vibration or motion of the button area. 
     This may be useful, for example, in a touch-sensitive mobile phone having a button or other input that is not physically depressed but instead operates when a touch is sensed. That is, instead of mechanical actuation, the button may initiate an input command when the phone senses a user is touching the button. (“Button,” in this case, refers to a particular portion of the touch screen as opposed to a separate, mechanically actuated input) By providing localized haptic feedback at the physical location of the button when it is touched, a user may know his touch was sensed and the input initiated/accepted. Thus, the linear vibrator  100  may be located beneath the button. In another embodiment, touching the button may toggle the vibrator between the boosted and normal modes. In such an embodiment, the haptic feedback may occur after the user input as toggled the operational mode and after the user input has ceased. Accordingly, the user input need not be present in order for a particular operational mode to be active; rather, the user input can impact the mode of haptic feedback even after the input has ceased. 
       FIG. 5  is a general flowchart showing one sample method for operating the linear vibrator described herein. The method begins in operation  500 , in which an actuation signal is received by the embodiment. In operation  505 , it is determined whether the vibrator  100  is to be driven in normal or boosted mode. 
     If normal mode is desired, operation  515  is executed and normal current is delivered to the linear vibrator  100 . This provides a generalized haptic output; the linear vibrator is driven so that the tap rod  125  does not impact the enclosure. Generally, the range of motion of the magnet  105  and tap rod  125  may be similar to that shown in  FIGS. 3A and 3B . Following operation  515 , operation  520  is executed. 
     By contrast, if a boosted mode is desired then operation  510  is executed. In operation  510 , sufficient current is provided to the linear actuator that it operates in the boosted mode described with respect to  FIG. 4 . That is, a higher level of current is supplied to the coil than in the normal mode of operation, and the magnet  105  is deflected sufficiently that the tap rod impacts the enclosure. As the magnet oscillates, the tap rod  125  repeatedly strikes the enclosure to provide localized haptic feedback. Following operation  510 , operation  520  is accessed. 
     In operation  520 , the embodiment determines if a termination condition is reached. The termination condition may vary and may depend on the mode in which the linear vibrator  100  is operating. For example, answering an incoming call may serve as a termination condition for the linear vibrator being driven in its normal mode. Similarly, the cessation of a capacitive input on a particular portion of a touch screen may serve as a termination condition when the linear vibrator is being driven in a boosted mode. 
     If no termination condition is reached, then the embodiment continues providing current to operate the linear vibrator in operation  525 . Periodically, the embodiment returns to operation  520  to again check for a termination condition. 
     If a termination condition is detected, then current to the vibrator is stopped and end state  530  is entered. 
     It should be appreciated that either current or voltage may drive the linear vibrator. Accordingly, references to current herein should be understood to encompass voltage, as necessary or appropriate. 
     Although embodiments have been described with respect to particular physical configurations and methods of operation, one of ordinary skill in the art will appreciate that alternatives exist. Such alternatives are contemplated and considered to be within the scope of protection.