PATENT DOCUMENT

Publication Number: US-9501912-B1
Application Number: US-201414165475-A
Country: US
Kind Code: B1

Title: Haptic feedback device with a rotating mass of variable eccentricity

Abstract:
A haptic element having a rotating element at least partially fixed to the rotating shaft of a motor. The rotating element dynamically reconfigures its center of mass to provide at least a first concentric rotation state and second eccentric rotation state. The transition between the concentric state and the eccentric state may be at least partially defined by a threshold angular velocity of the rotating shaft of the motor. As the motor approaches the threshold, the rotating element may be concentrically aligned with the axis of rotation of the rotating shaft of the motor. Once the threshold is reached, the mass element may be eccentrically aligned with the axis of rotation, initiating an immediate and perceivable haptic feedback.

Claims:
We claim: 
     
       1. A haptic element comprising:
 a motor comprising a shaft; and 
 a mass element coupled to the shaft comprising:
 a first operational configuration associated with a first angular velocity range of the shaft wherein a center of mass of the mass element is concentrically aligned with the shaft; and 
 a second operational configuration associated with a second angular velocity range of the shaft wherein the center of mass of the mass element is eccentrically aligned with the shaft. 
 
 
     
     
       2. The haptic element of  claim 1 , wherein the mass element comprises a first mass portion and a second mass portion, wherein:
 the first mass portion is rigidly coupled to the shaft; and 
 the second mass portion is configured to move outwardly from the shaft. 
 
     
     
       3. The haptic element of  claim 2 , wherein in the first operational configuration, the second mass portion is positioned to interface the first mass portion along the shaft. 
     
     
       4. The haptic element of  claim 2 , wherein in the second operational configuration, the second mass portion is positioned a select distance from the shaft and the first mass portion. 
     
     
       5. The haptic element of  claim 4 , wherein the select distance is defined at least in part by a movable coupling. 
     
     
       6. The haptic element of  claim 5 , wherein the movable coupling comprises at least one of a spring, an elastomer, an electromagnet, a permanent magnet, and a piston. 
     
     
       7. The haptic element of  claim 4 , wherein the select distance is defined at least in part by an outward motion limiter. 
     
     
       8. The haptic element of  claim 1 , further comprising a third operational configuration associated with a third angular velocity range of the shaft greater than the first angular velocity range, wherein the center of mass of the mass element is concentrically aligned with the shaft. 
     
     
       9. The haptic element of  claim 1 , wherein the mass element comprises a first mass portion and a second mass portion, wherein:
 the first mass portion is rigidly coupled to the shaft; and 
 the second mass portion is configured to pivot about the shaft. 
 
     
     
       10. The haptic element of  claim 9 , wherein in the first operational configuration, the second mass portion pivots to diametrically oppose the first mass portion about the shaft. 
     
     
       11. The haptic element of  claim 9 , wherein in the second operational configuration, the second mass portion pivots to interface the first mass portion. 
     
     
       12. A haptic feedback apparatus comprising:
 a mass element coupled to a driver motor and comprising:
 a nonhaptic mode associated with an angular velocity range of the driver motor; and 
 a haptic mode associated with a threshold angular velocity of the driver motor; 
 
 wherein:
 the threshold angular velocity defines an upper bound of a threshold angular velocity range. 
 
 
     
     
       13. An electronic device comprising:
 a housing; 
 a haptic element coupled to the housing and comprising:
 a motor comprising a shaft; and 
 a mass element coupled to the shaft and comprising:
 a first operational configuration associated with a first angular velocity range of the shaft wherein a center of mass of the mass element is concentrically aligned with the shaft; and 
 a second operational configuration associated with a second angular velocity range of the shaft wherein the center of mass of the mass element is eccentrically aligned with the shaft. 
 
 
 
     
     
       14. The electronic device of  claim 13 , wherein the mass element comprises a first mass portion and a second mass portion, wherein:
 the first mass portion is rigidly coupled to the shaft; and 
 the second mass portion is configured to move outwardly from the shaft. 
 
     
     
       15. The electronic device of  claim 14 , wherein in the first operational configuration, the second mass portion is positioned to interface the first mass portion along the shaft. 
     
     
       16. The electronic device of  claim 14 , wherein in the second operational configuration, the second mass portion is positioned a select distance from the shaft and the first mass portion. 
     
     
       17. The electronic device of  claim 16 , wherein the select distance is defined at least in part by a movable coupling. 
     
     
       18. The electronic device of  claim 17 , wherein the movable coupling comprises at least one of a spring, an elastomer, an electromagnet, a permanent magnet, and a piston. 
     
     
       19. The electronic device of  claim 16 , wherein the select distance is defined at least in part by an outward motion limiter. 
     
     
       20. The electronic device of  claim 13 , further comprising a third operational configuration associated with a third angular velocity range of the shaft greater than the first angular velocity range wherein the center of mass of the mass element is concentrically aligned with the shaft. 
     
     
       21. A method of providing haptic feedback comprising:
 spinning a shaft of a motor to a first angular velocity, the motor comprising a mass element coupled to the shaft, the mass element having a center of mass that is concentrically aligned with the shaft when the motor operates in a first mode; and 
 causing the center of mass of the mass element to eccentrically align with the shaft upon spinning the motor to a second angular velocity when the motor operates in a second mode. 
 
     
     
       22. The method of  claim 21 , further composing:
 slowing the shaft of the motor to the first angular velocity to transition from the second mode to the first mode. 
 
     
     
       23. The method of  claim 21 , further comprising:
 spinning the shaft of the motor to a third angular velocity; and 
 causing the center of mass of the mass element to concentrically align with the shaft.

Description:
TECHNICAL FIELD 
     This disclosure relates to haptic devices and, more particularly, to haptic feedback elements providing short and distinct pulses. 
     BACKGROUND 
     Many electronic devices include haptic elements to provide feedback to a user. For example, an electronic device such as a cellular telephone may leverage haptic elements to inform a user of an incoming call. In some examples, a haptic element may provide feedback through sustained or intermittent vibration over a period of time. Electronic devices which may benefit from haptic elements may include cellular telephones, smart phones, personal digital assistants, tablet computers, laptop computers, track pads, wearable devices, health devices, sports accessory devices, peripheral input devices, and so on. 
     Most haptic elements include an eccentric mass coupled to the rotating axis of an electric motor. When the motor rotates the eccentric mass about a shaft or other axis the haptic element typically experiences axially asymmetric forces, displacing the mass within a plane perpendicular to the axis of rotation. After reaching a sufficient angular velocity, the displacement of the mass may be perceived as a sustained vibration. 
     In other cases, a haptic element may be repeatedly activated and deactivated to simulate a pulsed vibration. Many haptic elements are structurally coupled to the housing of an electronic device, such that when the haptic element is activated, the electronic device housing vibrates. 
     In certain examples, the time required for the motor to reach the speed necessary for vibration to be perceptible (e.g., spin-up delay) may be distracting, confusing or frustrating to a user, even if the delay is minimal. In addition, a spin-up delay may undesirably limit the frequencies at which a haptic element may be pulsed. In still further examples, an eccentric mass haptic element may perceivably vibrate before reaching a maximum vibration intensity. In such a case, a user may perceive a haptic feedback of progressive intensity instead of a distinct and well-characterized haptic feedback. 
     Accordingly there may be a present need for an improved haptic element. 
     SUMMARY 
     Embodiments described herein may include or take the form of haptic elements which dynamically realign the center of mass of a rotating element to provide distinct and well-characterized haptic feedback. 
     Certain embodiments may include or take the form of a haptic element with a motor having a mass element coupled thereto. As the motor begins spinning, the mass may be positioned such that the center of mass of the mass element is aligned with the axis of rotation of the rotating shaft of the motor. Once the motor reaches a certain angular velocity (i.e., speed of rotation), the center of mass of the mass element may dynamically become eccentrically aligned with the rotating shaft of the motor. As a result of the sudden eccentricity of the mass, the element may immediately and perceivably vibrate. 
     Further embodiments described here may divide a mass element into a plurality of portions. In one example, a first mass portion and a second mass portion may be included. In these and related embodiments, the first mass portion may be rigidly coupled to the shaft whereas the second mass portion may be configured to move outwardly from the shaft or, alternately configured to pivot about the shaft. 
     In these and related embodiments, the first operational mode (i.e., concentric alignment) may position the second mass portion to interface the first mass portion along the shaft and the second operational mode (i.e., eccentric alignment) may position the second mass portion a select distance from the shaft and first mass portion. This positioning may result in a displacement of the center of mass of the mass element with respect to the axis of rotation. The second mass portion may transition between the first and second operational modes along a path at least partially defined by a movable coupling such as a spring, elastomer, electromagnet, permanent magnet, or piston. In other cases, the distance may be defined at least in part by an outward motion limiter such as a band, basket, or hoop. 
     In further embodiments, the haptic element may enjoy a third operational configuration. For example, once a selected angular velocity range is reached to transition the mass element from concentric alignment to eccentric alignment, a first mass portion may itself transition a distance from the shaft equal to the distance traveled by the second mass portion. In this manner, the first mass portion may become diametrically opposite to the second mass portion about the shaft. In such a configuration, the center of mass of the mass element may return to concentric alignment with respect to the axis of rotation of the motor. 
     Other embodiments described herein may relate to or take the form of a haptic feedback apparatus including a mass element coupled to a driver motor that may assume both a haptic and a nonhaptic mode. For example, a nonhaptic mode may be associated with a particular angular velocity range of the driver motor, and a haptic mode associated with a threshold angular velocity of the driver motor. In some cases the threshold angular velocity may define the upper bound of the angular velocity range associated with the nonhaptic mode. 
     Still further embodiments may relate to or take the form of an electronic device may include a housing having a haptic element coupled thereto and may include a motor may include a shaft, and a mass element coupled to the shaft may include a first operational configuration associated with a first angular velocity range of the shaft in some cases the center of mass of the mass element may be concentrically aligned with the shaft, and a second operational configuration associated with a second angular velocity range of the shaft in some cases the center of mass of the mass element may be eccentrically aligned with the shaft. 
     Still further embodiments discussed herein may relate to or take the form of a method of providing haptic feedback comprising spinning a motor to a first angular velocity, the motor comprising a shaft coupled to a mass element, the mass element concentrically aligned with the shaft, and causing the mass element to eccentrically align with the shaft upon spinning the motor to a second angular velocity. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
       Reference will now be made to representative embodiments illustrated in the accompanying figures. It should be understood that the following descriptions are not intended to limit the embodiments to one preferred embodiment. To the contrary, it is intended to cover alternatives, modifications, and equivalents as may be included within the spirit and scope of the described embodiments as defined by the appended claims. 
         FIG. 1  is a sample electronic device including a haptic element having a rotating mass of variable eccentricity. 
         FIG. 2  is an isometric side view of a sample haptic element having a rotating mass of variable eccentricity. 
         FIG. 3A  is a top plan view of the sample haptic element of  FIG. 2  taken along line  3 - 3 , showing a rotating mass in an axially balanced state. 
         FIG. 3B  is a top plan view of the sample haptic element of  FIG. 2  taken along line  3 - 3 , showing a rotating mass in an eccentric state. 
         FIG. 4A  is a side plan view of the sample haptic element of  FIG. 2  taken along line  4 - 4 , showing a rotating mass in an axially balanced state rotating at a first angular velocity. 
         FIG. 4B  is a side plan view of the sample haptic element of  FIG. 2  taken along line  4 - 4 , showing a rotating mass in an axially balanced state rotating at a second angular velocity. 
         FIG. 4C  is a side plan view of the sample haptic element of  FIG. 2  taken along line  4 - 4 , showing a rotating mass in a transition state between an axially balanced state and an eccentric state, rotating at a third angular velocity. 
         FIG. 4D  is a side plan view of the sample haptic element of  FIG. 2  taken along line  4 - 4 , showing a rotating mass in an eccentric state, rotating at a fourth angular velocity. 
         FIG. 5A  is a side plan view of the sample haptic element of  FIG. 2  taken along line  4 - 4 , showing a rotating mass in an eccentric state, rotating at a first angular velocity. 
         FIG. 5B  is a side plan view of the sample haptic element of  FIG. 2  taken along line  4 - 4 , showing a rotating mass in a transition state between an eccentric state and an axially balanced state, rotating at a second angular velocity. 
         FIG. 5C  is a side plan view of the sample haptic element of  FIG. 2  taken along line  4 - 4 , showing a rotating mass in an axially balanced state rotating at a third angular velocity. 
         FIG. 5D  is a side plan view of the sample haptic element of  FIG. 2  taken along line  4 - 4 , showing a rotating mass in an axially balanced state rotating at a fourth angular velocity. 
         FIG. 6A  is a sample graph illustrating exemplary angular velocity over time of a haptic element with a rotating mass of fixed eccentricity. 
         FIG. 6B  is a sample graph illustrating a sample coordinate of the center of mass of the haptic element with a rotating mass of fixed eccentricity partially described with respect to the sample graph shown in  FIG. 6A . 
         FIG. 7A  is a sample graph illustrating exemplary angular velocity over time of a haptic element with a rotating mass of variable eccentricity. 
         FIG. 7B  is a sample graph illustrating exemplary coordinates of the center of mass of the haptic element with a rotating mass of variable eccentricity partially described with respect to the sample graph shown in  FIG. 7A . 
         FIG. 8A  is a top plan view of the sample haptic element showing two rotating masses, each in a first axially balanced state. 
         FIG. 8B  is a top plan view of the sample haptic element showing two rotating masses in an eccentric state. 
         FIG. 8C  is a top plan view of the sample haptic showing two rotating masses in a second axially balanced state. 
         FIG. 9A  is a top plan view of the sample haptic element of  FIG. 2  taken along line  9 - 9 , showing a rotating mass held in an axially balanced state by two springs under tension. 
         FIG. 9B  is a top plan view of the sample haptic element of  FIG. 9A  showing the rotating mass in an eccentric state. 
         FIG. 10  is a top plan view of an alternate exemplary haptic element related to  FIG. 2  taken along line  9 - 9 , showing a rotating mass in an eccentric state. 
         FIG. 11  is a top plan view of an alternate exemplary haptic element related to  FIG. 2  taken along line  9 - 9 , showing a rotating mass in an eccentric state. 
         FIG. 12A  is a side plan view of the sample haptic element showing a rotating mass held in an axially balanced state. 
         FIG. 12B  is a side plan view of the sample haptic element showing the rotating mass of  FIG. 11A  in an eccentric state. 
         FIG. 13  is a side plan view of a sample haptic element showing a rotating mass held in an eccentric state. 
         FIG. 14  is a side plan view of a sample haptic element showing a rotating mass held in an eccentric state. 
     
    
    
     The use of the same or similar reference numerals in different drawings indicates similar, related, or identical items. 
     DETAILED DESCRIPTION 
     Embodiments discussed herein may take the form of a rotatable haptic element having a dynamically-realigned center of mass. In many embodiments, the haptic element may be attached to the shaft of a motor. The haptic element may include a mass element that may be separabley multi-part. For example, as the motor begins spinning, the haptic element may be positioned such that the center of mass of the mass element is aligned with the axis of rotation of the shaft of the motor. In this manner, the haptic element is axially balanced and may spin without perceivably vibrating. 
     Once the motor reaches a certain angular velocity, the center of mass of the h element may dynamically realign with respect to the rotating shaft of the motor such that the mass element spins eccentrically. When the motor rotates the eccentric mass it typically experiences axially asymmetric forces, displacing the mass within a plane perpendicular to the axis of rotation. The rapid displacement may cause a vibration in the housing. In other words, as a result of the sudden eccentricity of the mass, the haptic element and the electronic device housing may immediately and perceivably vibrate. 
     In certain examples the mass element may include two distinct parts. For example, the mass element may take the form of a cylinder that is diametrically divided into two parts. A first of the two equal parts may be rigidly affixed to the rotating shaft of the motor. A second of the two equal parts may be movable to a certain distance in a direction at least partially perpendicular to the axis of rotation. Movement of the movable second part may be controlled or guided. For example, a retractable extension may control the separation of the movable second part from the fixed first part along a rectilinear or arcuate path to a certain distance away from the axis of rotation. 
     In some examples, the movement of the movable second part may be defined at least in part by an outward motion limiter such as a band, basket, or hoop. For example, a hoop or basket attached to the fixed first part and positioned at a certain distance outwardly from the shaft may catch the movable second mass as it extends outwardly from the shaft. 
     In some embodiments, the movement of movable second part may be forcibly limited by a retaining feature. The retaining feature may be a spring, elastomer, electromagnet, permanent magnet, piston, and so on. In this manner, movement or displacement of the movable element may require a selectable or configurable amount of force. 
     In one embodiment, a spring under tension may forcibly hold the two mass elements together to clasp the shaft of the motor. As the motor and spring-clasped portions of the mass element rotate at increasing angular velocity, the retaining force exerted on the mass element by the spring may be overcome by the centrifugal force resulting from the circular path of the mass element. Once the retaining force is overcome, the movable mass element may extend outwardly from the shaft, thus shifting the center of mass of the mass element away from the axis of rotation of the shaft. In other words, once the two-part mass element retained together by a spring reaches a certain angular velocity, one part may move outward causing an off center mass with respect to the shaft and thus eccentric rotation of the mass element. 
     In certain examples, this eccentricity may reduce the angular velocity of the motor. In some cases, the reduction in the angular velocity of the motor as a result of the eccentricity may cause the retaining element (e.g., spring) to overcome the centrifugal force, resulting in the movable portion retracting back into the concentric position after a brief period of eccentricity. In this manner, a short and well-characterized haptic pulse may be perceived. In certain examples a short haptic pulse may provide a tapping or knocking sensation. In an alternate embodiment, the angular velocity of the motor may be maintained to prevent the reduction in speed as a result of sudden eccentricity in order to provide a sustained vibration. 
     In these and related embodiments, the haptic element may assume both a haptic and a nonhaptic mode. 
     In some embodiments, the haptic element may be included in a portable electronic device configured in the form of a cellular telephone. A processor within the portable electronic device may be coupled to the haptic element in order to provide haptic notifications or other indications to a user of the device. For example, the cellular telephone may be enabled to notify a user of an incoming telephone call and to separately notify a user of an incoming message. In some examples, the cellular telephone may desirably provide a series of short and distinct pulses to notify a user of the message and a long sustained vibration to notify a user of the phone call. 
     In other embodiments, the haptic element may be included in a portable electronic device configured in the form of a wearable health assistant that provides health-related information (whether real-time or not) to the user, authorized third parties, and/or an associated monitoring device. The health-related information or data may include, but may not be otherwise limited to heart rate data, blood pressure data, temperature data, oxygen level data, diet/nutrition information, medical reminders, health-related tips or information, or other health-related data. In one example, the wearable heath assistant may be configured to notify a user or a third party of a change in health-related information by providing a series of distinct pulses. In certain embodiments, an associated monitoring device may be, for example, a tablet computing device, phone, personal digital assistant, computer, and so on. 
     In one embodiment, the wearable health assistant may be configured to provide biofeedback. For example, a wearable health assistant may pulse at a rate based at least in part on or otherwise associated with a detected or target heart rate. In another example, the wearable health assistant may pulse at a rate based at least in part on or otherwise associated with a detected or target breathing rate. In another example, the wearable heath assistant may attempt to awaken a sleeping user at a particular time or after a particular duration with distinct haptic pulses of progressively increasing intensity or duration. In some examples, the wearable health device may be configured to monitor health-related data associated with the sleep cycle of user. In these and related embodiments the wearable health device may augment or determine an ideal time to begin attempting to wake a sleeping user. 
     In other embodiments, the haptic element may be included in a portable electronic device configured in the form of a peripheral input device associated with an associated device such as a computer mouse or track pad. The haptic element may be configured to provide haptic pulses or sustained vibrations in response to requests from a processor associated with the portable electronic device or, in alternative embodiments, from the associated device. The associated device may be, for example, a tablet computing device, phone, personal digital assistant, computer, and the like. 
     In further embodiments, more than one haptic element may be included in a portable electronic device. Each independent device may be configured to provide the same or different haptic feedback. For example, in one embodiment a first haptic element may enjoy an eccentric state defined at a first angular velocity and a second haptic element may enjoy an eccentric state defined at a second angular velocity. In these embodiments, certain notifications may be provided by the first haptic element and other notifications may be provided by the second haptic element. In other embodiments, both haptic elements may be operated at the same time, providing complementary haptic feedback. In still further embodiments, the first haptic element may be configured to provide feedback that either constructively or destructively interferes with the feedback provided by the second haptic feedback. For example, the eccentric states of the first and second haptic elements may be triggered at different angular velocity, which in turn may translate to different vibration frequencies. 
     In further embodiments, more than one set of mass elements may be coupled to the rotating axis of a mass element. In certain embodiments, multiple cylindrical mass elements (as one example, disks), each diametrically divided into equal pairs, may be positioned along the same axis. In this manner, at a first angular velocity the first of the multiple cylindrical mass elements may transition to an eccentric state. At a second and faster angular velocity the second of the multiple cylindrical mass elements may transition into an eccentric state. In this manner, the total mass eccentricity rotated about the shaft of the motor may be incrementally increased or decreased to correspondingly increase or decrease the haptic pulse effect. Accordingly, the haptic element may provide selectable intensity. 
     Reference will now be made to representative embodiments presented in the accompanying figures. It is understood that the following figures are not intended to limit the disclosure to one preferred embodiment but instead, to the contrary, it is intended to cover alternatives, modifications, and equivalents as may be included within the spirit and scope of the described embodiments as defined by the appended claims. 
       FIG. 1  is a sample electronic device  100  including a haptic element with a rotating mass of variable eccentricity. The electronic device  100  may, for example, be embodied as a portable or handheld electronic devices, such as a smart phone having a housing  102  and a display area  104  that consumes a majority if not all of the front surface of the electronic device  100 . The electronic device may include one or more physical buttons  106  that a user may engage to interact with the electronic device  100 . 
     The display area  104  of electronic device  100  may be embodied in a variety of ways. In one example, the display area  104  consists of at least a display such as a flat panel display such as, for example, a liquid crystal display or a thin film transistor display. The display area  104  may additionally include a cover window that is positioned over a display to provide additional structural support and scratch resistance. A haptic element, as described herein, may be structurally coupled to the housing  102  such that when the haptic element vibrates, a user may perceive the electronic device  100  to vibrate. 
       FIG. 2  is an isometric side view of a sample haptic element  200  having a rotating mass of variable eccentricity. The haptic element  200  includes a rotating actuator  202  having a shaft  204  extending at least partially therefrom. The shaft  204  may be rotated through a range of speeds by the rotating actuator  202 . In certain embodiments, the rotating actuator may be an electric motor and the shaft  204  may extend from the central axis of the motor. 
     Coupled to the shaft  204  is a mass element  206 . The mass element  206  may have a cylindrical or substantially cylindrical shape that is axially aligned with the shaft  204 . The mass element  206  may be diametrically divided into two equal or substantially equal portions, shown as the mass portions  208  and  210 . In further embodiments, the mass elements may not necessarily be diametrically divided into equal parts. For example, in one embodiment, one or more mass portions may be defined by a chord smaller than the diameter of a cylinder. In still further embodiments, one or more mass portions may be defined by an angular segment of a cylinder. In still further embodiments the mass element may take a non-cylindrical shape. 
     As illustrated, the mass portions  208  and  210  are positioned to clasp around the shaft  204  such that when the shaft  204  and mass element  206  rotate in a first direction  212 , such as shown in  FIG. 3A , the mass element  206  is balanced about the axis of rotation. 
     In many embodiments, the positioning of the mass elements  208  and  210  define a center of mass of the mass element  206 . One may appreciate that the center of mass of an object of uniform density is the geometric centroid of the object. For example, the center of mass of a sphere of uniform density is the exact center of the sphere. In another example, the center of mass of a cylinder of uniform density is a point along the major axis of the cylinder at the midpoint of the cylinder&#39;s height. Throughout this disclosure, it is presumed that elements are of uniform density such that the center of mass is equal to the geometric centroid. However, one may appreciate that uniform density or uniform distributions of mass are not required and that multiple distributions of mass are contemplated. As illustrated, one may appreciate that the center of mass of the mass element  206  is located along the axis of the shaft  204 . In this manner, as the shaft  204  and mass element  206  do not vibrate or displace with respect to the axis of rotation as the rotating actuator  202  increases rotational speed. 
       FIG. 3A  is a top plan view of the sample haptic element of  FIG. 2  taken along line  3 - 3 , showing a rotating mass in an axially balanced state. As with  FIG. 2 , the haptic element  200  includes a rotating actuator  202  having a shaft  204  to which the mass element  206  and the respective mass portions  208 ,  210  are coupled.  FIG. 3A  shows the mass element  206  rotating in a first direction  212  at a first angular velocity, illustrated generally by the magnitude of the arrow identifying the first direction  212  of rotation. As the angular velocity of the rotating actuator  202  increases, the mass portions  208 ,  210  also rotate about the shaft at increasing angular velocity. At a certain angular velocity, the mass portion  210  may extend outwardly from the axis of rotation of the shaft  204 , as shown in  FIG. 3B . 
     One may appreciate that in this configuration, the center of mass of the mass element  206  shifts outwardly in response to the outward movement of the mass portion  210 . In this manner, the center of mass of the mass element  206  is not aligned with the axis of rotation or, in other words, the mass element  206  may assume an eccentric alignment. As a result of the eccentric alignment, the mass element  206  may experience axially asymmetric forces, which encourages the displacement of the mass element  206  within a plane perpendicular to the axis of rotation of the shaft  204 . 
       FIG. 4A  is a side plan view of the sample haptic element  200  of  FIG. 2  taken along line  4 - 4 , showing the mass element  206  in an axially balanced state rotating at a first angular velocity  214 . As the angular velocity continues to increase to a second angular velocity  216 , as shown in  FIG. 4B , the mass element  206  may remain balanced. However, as the angular velocity continues to increase to a third angular velocity  218  as shown in  FIG. 4C , a centrifugal force  220  may act to move the mass portion  210  outwardly with respect to the shaft  204 . As the angular velocity continues to increase to a fourth angular velocity  222  as shown in  FIG. 4D , the centrifugal force  220  may act to retain the mass portion  210  in an eccentric state. 
     In many embodiments, the transition of the mass element  206  from a concentric alignment to an eccentric alignment may correspondingly increase the torque required to maintain the angular velocity of mass element  206  at the fourth angular velocity  222 . In certain embodiments, the power supplied to the rotating actuator may be increased. In other embodiments, the increase in torque may correspond to a decrease in the angular velocity of mass element  206 . The reduction in angular velocity may correspondingly decrease the centrifugal force retaining the mass portion  210  in the eccentric state. As a result, as shown in  FIG. 5A , a retaining force  224  may overcome the centrifugal force  220 , acting to pull the mass portion  210  back toward the axis of rotation defined by the shaft  204 . As the angular velocity continues to decrease, the retaining force may continue to pull the mass portion  210  toward the shaft  204 , as illustrated in  FIG. 5B . The angular velocity continues to decrease from angular velocity  226  in  FIG. 5A  to angular velocity  228  in  FIG. 5B  to angular velocity  230  in  FIG. 5C  to angular velocity  232  in  FIG. 5D . In this manner, the mass portion  210  may once again be concentrically aligned with the axis of the shaft  204 , as illustrated by  FIGS. 5C and 5D . 
     One may appreciate a haptic element having fixed eccentricity increase its vibration intensity by increasing the number of rotations per minute of the eccentric mass. For example,  FIG. 6A  illustrates a theoretical angular velocity ν θ  of a haptic element with a rotating mass of fixed eccentricity. As shown, at time t 0 , the angular velocity of the haptic element may be equal to zero (i.e., the haptic element is at rest). From time t 0  to t 1 , the haptic element may be in a first state s 1 , during which the angular velocity ν θ  may increase. During s 1 , the angular of the haptic element at time t 1  may be insufficient to cause a user-perceivable vibration. In other words, the haptic element may be spinning too slowly for a user to perceive the spin as a vibration. In some examples, this period may be referred to as the “spin-up” time. 
     At time t 1 , the angular velocity may be of sufficient magnitude to be perceived as a vibration by a user. As time passes, the angular velocity ν θ  may increase. In other words, the haptic element may spin faster and faster. In other words, at t 1  as user may feel a vibration of increasing intensity. At a certain point, the haptic element may no longer be able to spin faster. At this point, the haptic element has reached a maximum angular velocity ν max . In some examples, the limit may be defined by the amount of power supplied to the haptic element. In other examples, the limit may be defined by one or more physical properties of the haptic element. In still further examples, the limit may be defined by software operating on the electronic device controlling the haptic element. 
     The haptic element may stay at the maximum angular velocity ν max  for a period of time before power to the haptic element is turned off. Once power is turned off, one may appreciate that the haptic element may begin to slow, decelerating into state s 3 , the point at which a user may no longer perceive the haptic element to vibrate. 
     In this manner, the maximum vibration intensity of a haptic element having a fixed-eccentricity spinning mass may be correlated with the maximum angular velocity. As shown in  FIG. 6A , a period of time may be required for the maximum angular velocity to be reached. As a result, a user may perceive a haptic feedback of progressive intensity instead of a distinct and well-characterized haptic feedback. 
     Corresponding to  FIG. 6A ,  FIG. 6B  shows the radius r cm  of the center of mass of the haptic element with a rotating mass of fixed eccentricity. As the eccentricity of the rotating mass is fixed, the radius of the center of mass does not change. 
       FIG. 7A  is a sample graph illustrating exemplary angular velocity over time of a haptic element with a rotating mass of variable eccentricity.  FIG. 7A  illustrates a theoretical angular velocity ν θ  over time of a haptic element with a rotating mass of variable eccentricity, such as the haptic element shown in  FIG. 4A . At time t 0 , the angular velocity of the haptic element may be equal to zero because the haptic element is at rest and is not yet spinning. From time t 0  to t 1 , the haptic element may be in a first state s 1 . In this state, the rotating mass may be balanced (e.g.,  FIG. 4A ) such that the center of mass of the rotating mass is centered about the axis of rotation. During the first state s 1 , the angular velocity may increase without causing the haptic element to become eccentric, as shown, for example, in  FIG. 4B . 
     At time t 1 , the angular velocity of the haptic element may cause the separation of the mass element to an eccentric state. For example as shown in  FIG. 4C and 4D , the mass element may separate in a direction perpendicular to the. Once the haptic element is eccentric, the haptic element may vibrate as it revolves off-axially about the shaft. The housing of the electronic device may also vibrate. In this manner, the rapid shift to an eccentric position (unbalanced) from a concentric position (balanced) may cause the haptic element to immediately slow due to the sudden increase in torque required to rotated the eccentric mass. This reduction in speed may occur within state s 2 . 
     At time t 2 , the angular velocity of the haptic element may be insufficient to maintain the eccentricity of the haptic element. As a result, the haptic element may reconfigure into the concentric position, as shown in  FIGS. 5A and 5B . As a result of the shift to the concentric position, the haptic element may briefly increase in angular velocity as a result in the reduction in torque required to spin the concentric mass (i.e., conservation of angular momentum). In certain examples, this slight increase in the angular velocity may be below the amount required to shift the mass into the eccentric position. 
     Corresponding to  FIG. 7A ,  FIG. 7B  shows the radius r 0  and r 1  of the center of mass of the haptic element with a rotating mass of variable eccentricity. As shown, the center of mass of the haptic element have a radius equal to 0 when the mass is concentric with the axis of the rotating actuator element coupled thereto. Similarly at t 1 , the radius of the center of mass may immediately shift to r 1 . At t 2 , the radius of the center of mass of the haptic element may shift back to 0. 
     Other embodiments described herein may relate to or take the form of a haptic element having a rotating mass with more than one eccentric state or more than one balanced state. For example,  FIG. 8A  shows a top plan view of the sample haptic element  200  of  FIG. 2  taken along line  3 - 3 , showing two rotating masses portions  208 ,  210  each in a first axially balanced state. Corresponding to a first angular velocity, the mass portion  210  may extend away from the central axis to become eccentric, as shown in  FIG. 8B . As the angular velocity of the haptic element  200  continues to increase, mass portion  208  may also extend away from the central axis, as shown in  FIG. 8C , forming a second axially balanced state. As the angular velocity of the haptic element  200  decreases, each of the mass portions  208  may retract into the concentric position. 
     Other embodiments described herein may relate to or take the form of a retaining element or retaining features for use within a haptic element of variable eccentricity. As described, a rotating mass may include a movable part that may alter the center of mass of the rotating mass. In some embodiments, the movement of movable part may be forcibly limited by a retaining feature such as a spring, elastomer, electromagnet, permanent magnet, or piston and the like. The retaining element may exert a centripetal force on the mass element as it rotates. At a sufficient angular velocity, the centripetal force may be overcome and the movable part may extend outwardly from the shaft, immediately shifting the center of mass of the mass element away from the axis of rotation. The movable part may extend a rectilinear or arcuate path to a fixed or variable distance away from the axis of rotation. 
       FIG. 9A  and  FIG. 9B  show a top plan view of the sample haptic element of  FIG. 2  taken along line  9 - 9 , showing a rotating mass  910  held in an axially balanced state by two springs  920  under tension. One may appreciate that the tension of the springs  920  correlates to the amount of retaining force the springs may provide to keep the movable mass  910  in the concentric position. 
     In other embodiments, the retaining feature may include a permanent magnet or electromagnet, such as the embodiment shown in  FIG. 10 . In a first embodiment, a magnet  1020   a  may be fixedly coupled to the rotating shaft. A complementary magnet  1020   b  may be fixedly coupled to the movable mass  1010 . The magnet portions  1020   a ,  1020   b  may be oriented to attract to one another such that with a low angular velocity, the movable mass  1010  may be retained in a concentric position. 
     One may appreciate that the mass of the movable element  1010  may be slightly less than a fixed element  1008  due to the internal geometry necessary to receive the retaining feature. In some embodiments, the fixed element  1008  may be constructed of a different material than the movable element  1010  to account for the difference in mass resulting from the difference in geometry. In other embodiments, the geometry of the fixed element  1008  may be augmented to account for the reduced mass of the movable element  1010 . 
     In other embodiments, alternate retaining features may be provided. For example,  FIG. 11  showing a retaining element  1120  comprised of an elastomer. The elasticity of the elastomer selected may vary from embodiment to embodiment. 
     In other embodiments, a first mass portion and a second mass portion may be included in a rotating mass of varying eccentricity. In these and related embodiments, the first mass portion may be rigidly coupled to the shaft whereas the second mass portion may be configured to pivot about the shaft. For example,  FIG. 12A  shows a side plan view of a sample haptic element  1200 , showing a rotating mass  1206  composed of two mass portions  1208 ,  1210  held in an axially balanced state about the axis of rotation. At a selected angular velocity, or at a selected time, the mass portions  1208 ,  1210  may pivot to interface one another as shown in  FIG. 12B . 
     In still other embodiments, a first mass portion and a second mass portion may be included in a rotating mass of varying eccentricity having unequal masses. For example,  FIG. 13  shows a top plan view of a sample haptic element  1300 , showing a rotating mass composed of two mass portions  1308 ,  1310  held in an eccentric state about the axis of rotation. At a selected angular velocity the mass portion  1310  may extend outwardly a selected distance to shift the center of mass. The mass portions  1308 ,  1310  may have unequal geometries and may have unequal masses. 
     In further examples, the movement of the movable mass portion may be defined at least in part by an outward motion limiter such as a band, basket, or hoop. For example,  FIG. 14  shows a top plan view of a sample haptic element  1400 , showing a rotating mass composed of two mass portions  1408 ,  1410  held in an eccentric state about the axis of rotation. Also depicted is an outward motion limiter  1412 , fixed to the mass portion  1408  and positioned a certain distance outwardly from the shaft. The outward motion limiter  1412  may catch the mass portion  1410  as it extends outwardly. 
     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 target 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.

Metadata:
Filing Date: 20140127
Publication Date: 20161122
Grant Date: 20161122
Priority Date: 20140127
Inventors: HAVSKJOLD DAVID G.
WEISS SAMUEL B.
Assignee: APPLE INC
CPC Classifications: [{"code": "G06F3/016", "inventive": true, "first": false, "tree": "[]"}, {"code": "G08B6/00", "inventive": true, "first": true, "tree": "[]"}, {"code": "G06F1/00", "inventive": false, "first": false, "tree": "[]"}, {"code": "G08B6/00", "inventive": true, "first": true, "tree": "[]"}, {"code": "G06F3/016", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F1/00", "inventive": false, "first": false, "tree": "[]"}]
Family ID: 57287702