PATENT DOCUMENT

Publication Number: US-9949390-B1
Application Number: US-201715489926-A
Country: US
Kind Code: B1

Title: Electronic device including movable magnet based actuator for deforming a display and related methods

Abstract:
An electronic device may include a device housing and a display carried by the device housing. The electronic device may also include an actuator carried between the device housing and the display. The actuator may include an actuator body having an actuator bottom and a sidewall extending upwardly therefrom, a first guide member carried by the actuator bottom and spaced inwardly from adjacent portions of the sidewall to define a channel, and at least one coil carried by the sidewall. The actuator may also include a magnet being moveable within the channel and an actuator top coupled to the magnet and that includes a second guide member cooperating with the first guide member. The electronic device may also include a controller configured to drive the at least one coil to relatively move the actuator bottom and actuator top to thereby deform the display.

Claims:
That which is claimed is: 
     
       1. An electronic device comprising:
 a device housing; 
 a display carried by the device housing; 
 an actuator carried between the device housing and the display and comprising
 an actuator body having an actuator bottom and a sidewall extending upwardly therefrom, 
 a first guide member carried by the actuator bottom and spaced inwardly from adjacent portions of the sidewall to define a channel, 
 at least one coil carried by the sidewall, 
 a magnet being moveable within the channel, and 
 an actuator top coupled to the magnet and comprising a second guide member cooperating with the first guide member; and 
 
 a controller configured to drive the at least one coil to relatively move the actuator bottom and actuator top to thereby deform the display. 
 
     
     
       2. The electronic device of  claim 1  wherein the first guide member comprises a body having a passageway therein. 
     
     
       3. The electronic device of  claim 1  wherein the second guide member comprises a projection received within the passageway of the body. 
     
     
       4. The electronic device of  claim 1  wherein the actuator further comprises at least one biasing member carried within the passageway of the body. 
     
     
       5. The electronic device of  claim 1  wherein the actuator top comprises a top plate and a spacer between the top plate and magnet. 
     
     
       6. The electronic device of  claim 1  wherein the actuator body comprises a ferrous material. 
     
     
       7. The electronic device of  claim 1  wherein the actuator body comprises ferrous steel. 
     
     
       8. The electronic device of  claim 1  wherein the sidewall of the actuator has a cylindrical shape. 
     
     
       9. The electronic device of  claim 1  wherein the at least one coil comprises copper. 
     
     
       10. The electronic device of  claim 1  wherein the actuator top comprises a ferrous material. 
     
     
       11. The electronic device of  claim 1  wherein the actuator top comprises a magnetic actuator top. 
     
     
       12. The electronic device of  claim 1  wherein the magnet comprises a permanent magnet. 
     
     
       13. The electronic device of  claim 1  wherein the display comprises a touch display. 
     
     
       14. An actuator to be carried between a device housing and a display of an electronic device, the actuator comprising:
 an actuator body having an actuator bottom and a sidewall extending upwardly therefrom; 
 a first guide member carried by the actuator bottom and spaced inwardly from adjacent portions of the sidewall to define a channel; 
 at least one coil carried by the sidewall; 
 a magnet being moveable within the channel; and 
 an actuator top coupled to the magnet and comprising a second guide member cooperating with the first guide member, the actuator top configured to move relative to the actuator bottom to thereby deform the display based upon driving the at least one coil. 
 
     
     
       15. The actuator of  claim 14  wherein the first guide member comprises a body having a passageway therein. 
     
     
       16. The actuator of  claim 14  wherein the second guide member comprises a projection received within the passageway of the body. 
     
     
       17. The actuator of  claim 14  further comprising at least one biasing member carried within the passageway of the body. 
     
     
       18. The actuator of  claim 14  wherein the actuator top comprises a top plate and a spacer between the top plate and magnet. 
     
     
       19. A method of making an actuator to be coupled between a device housing and a display of an electronic device, the method comprising:
 forming an actuator body having an actuator bottom and a sidewall extending upwardly therefrom; 
 positioning a first guide member carried by the actuator bottom and spaced inwardly from adjacent portions of the sidewall to define a channel; 
 positioning at least one coil carried by the sidewall, 
 positioning a magnet to be moveable within the channel; and 
 coupling an actuator top to the magnet so that a second guide member cooperates with the first guide member and so that upon driving the at least one coil, the actuator top and the actuator bottom relatively move to thereby deform the display. 
 
     
     
       20. The method of  claim 19  wherein the first guide member comprises a body having a passageway therein. 
     
     
       21. The method of  claim 19  wherein the second guide member comprises a projection received within the passageway of the body. 
     
     
       22. The method of  claim 19  further comprising positioning at least one biasing member carried within the passageway of the body. 
     
     
       23. The method of  claim 19  wherein the actuator top comprises a top plate and a spacer between the top plate and magnet.

Description:
RELATED APPLICATION 
     The present application claims the priority benefit of provisional application Ser. No. 62/437,810 filed on Dec. 22, 2016 and provisional application Ser. No. 62/437,804 filed on Dec. 22, 2016, the entire contents of both are herein incorporated in their entirety by reference. 
    
    
     TECHNICAL FIELD 
     The present disclosure relates to the field of electronics, and, more particularly, to the field of haptics. 
     BACKGROUND 
     Haptic technology is becoming a more popular way of conveying information to a user. Haptic technology, which may simply be referred to as haptics, is a tactile feedback based technology that stimulates a user&#39;s sense of touch by imparting relative amounts of force to the user. 
     A haptic device or haptic actuator is an example of a device that provides the tactile feedback to the user. In particular, the haptic device or actuator may apply relative amounts of force to a user through actuation of a mass that is part of the haptic device. Through various forms of tactile feedback, for example, generated relatively long and short bursts of force or vibrations, information may be conveyed to the user. 
     SUMMARY 
     An electronic device may include a device housing and a display carried by the device housing. The electronic device may also include an actuator carried between the device housing and the display. The actuator may include an actuator body having an actuator bottom and a sidewall extending upwardly therefrom, a first guide member carried by the actuator bottom and spaced inwardly from adjacent portions of the sidewall to define a channel, and at least one coil carried by the sidewall. The actuator may also include a magnet being moveable within the channel and an actuator top coupled to the magnet and that includes a second guide member cooperating with the first guide member. The electronic device may also include a controller configured to drive the at least one coil to relatively move the actuator bottom and actuator top to thereby deform the display. 
     The first guide member may include a body having a passageway therein, for example. The second guide member may include a projection received within the passageway of the body. 
     The actuator may also include at least one biasing member carried within the passageway of the body, for example. The actuator top may include a top plate and a spacer between the top plate and magnet. 
     The actuator body may include a ferrous material, for example, ferrous steel. The sidewall of the actuator may have a cylindrical shape. 
     The at least one coil may include copper, for example. The actuator top may include a ferrous material. 
     The actuator top may include a magnetic actuator top. The magnet may include a permanent magnet. The display may include a touch display. 
     A method aspect is directed to a method of making an actuator to be coupled between a device housing and a display of an electronic device. The method may include forming an actuator body having an actuator bottom and a sidewall extending upwardly therefrom and positioning a first guide member carried by the actuator bottom and spaced inwardly from adjacent portions of the sidewall to define a channel. The method may also include positioning at least one coil carried by the sidewall, positioning a magnet to be moveable within the channel, and coupling an actuator top to the magnet so that a second guide member cooperates with the first guide member and so that upon driving the at least one coil the actuator top and the actuator bottom relatively move to thereby deform the display. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of an electronic device in accordance with an embodiment. 
         FIG. 2  is a schematic block diagram of the electronic device of  FIG. 1 . 
         FIG. 3  is a perspective schematic cross-sectional view of an actuator according to an embodiment. 
         FIG. 4  is a side schematic cross-sectional view of the actuator of  FIG. 3 . 
         FIG. 5  is a side schematic cross-sectional view of the actuator according to another embodiment. 
         FIG. 6  is a diagram illustrating simulated magnetic flux lines with the coil of an actuator not being driven according to an embodiment. 
         FIG. 7  is a diagram illustrating simulated magnetic flux lines with the coil of an actuator not being driven according to an embodiment. 
         FIG. 8  is a diagram illustrating simulated magnetic flux lines with the coil of an actuator not being driven according to an embodiment. 
         FIG. 9  is a diagram illustrating flux leakage beyond an actuator according to an embodiment and into the device housing. 
         FIG. 10  is a graph illustrating simulated flux leakage in the xy-axis plane with an actuator top that does not include magnetic or ferromagnetic material according to an embodiment. 
         FIG. 11  is a graph illustrating simulated flux leakage in the z-axis plane with the actuator top of  FIG. 10 . 
         FIG. 12  is a graph illustrating simulated flux leakage in the xy-axis plane with an actuator top that includes ferromagnetic material according to an embodiment. 
         FIG. 13  is a graph illustrating simulated flux leakage in the z-axis plane with the actuator top of  FIG. 12 . 
         FIG. 14  is a graph illustrating simulated flux leakage in the xy-axis plane with an actuator top that include magnetic material or magnetic according to an embodiment. 
         FIG. 15  is a graph illustrating simulated flux leakage in the z-axis plane with the actuator top of  FIG. 14 . 
         FIG. 16  is a side schematic cross-sectional diagram of an actuator in accordance with an embodiment. 
         FIG. 17  is a perspective view of the actuator of  FIG. 16 . 
         FIG. 18  is a perspective cross-sectional diagram of the actuator of  FIG. 16 . 
         FIG. 19  is a diagram illustrating simulated flux lines with the coil of the actuator of  FIG. 16  not being driven. 
         FIG. 20  is a diagram illustrating simulated flux lines with the coil of the actuator of  FIG. 16  being driven. 
         FIG. 21  is a graph of simulated stroke distance versus actuation force for the actuator of  FIG. 16 . 
         FIG. 22  is a graph of simulated stroke distance versus force according to an embodiment. 
         FIG. 23  is a graph of simulated stroke distance versus force according to an embodiment including a restoring biasing member. 
         FIG. 24  is a graph of simulated stroke distance versus force according to an embodiment. 
         FIG. 25  is a side schematic cross-sectional view of an actuator including a restoring biasing member in accordance with an embodiment. 
         FIG. 26  is an exploded perspective cross-sectional view of an actuator including a restoring biasing member in accordance with an embodiment. 
         FIG. 27  is a graph of magnet offset versus magnet force illustrating in-plane restoring forces in accordance with an embodiment. 
         FIG. 28  is a portion of an electronic device including a schematic cross-sectional view of an actuator according to another embodiment. 
         FIG. 29  is a portion of the actuator of  FIG. 28  illustrating a desired magnetic flux path and undesired flux leakage. 
         FIG. 30  is a diagram of simulated magnetic flux density and magnetic flux streamlines for an actuator according to an embodiment. 
         FIG. 31  is a diagram of simulated in-plane flux density for an actuator according to an embodiment. 
         FIG. 32  is a schematic cross-sectional view of an actuator and ferrous shielding bodies according to another embodiment. 
         FIG. 33  is a schematic cross-sectional view of an actuator according to another embodiment. 
         FIG. 34  is a diagram of simulated in-plane flux density for the actuator in  FIG. 33 . 
         FIG. 35  is a schematic cross-sectional view of an actuator according to another embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     The present invention will now be described more fully hereinafter with reference to the accompanying drawings, in which preferred embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Like numbers refer to like elements throughout, and prime and multiple prime notation and numbers in increments of 100 are used to indicate similar elements in alternative embodiments. 
     Referring initially to  FIGS. 1-4 , an electronic device  20  includes a device housing  21  and a display  22  carried by the housing. A controller  23  is also carried by the device housing  21 . The electronic device  20  is illustratively in the form of a mobile wireless communications device, such as, for example, a smart telephone. However, the electronic device  20  may be another type of device, for example, a tablet, laptop, or wearable device. 
     Wireless communications circuitry  25  (e.g. cellular, WLAN Bluetooth, etc.) is also carried within the device housing  21  and coupled to the device controller  23 . The wireless communications circuitry  25  cooperates with the device controller  23  to perform at least one wireless communications function, for example, for voice and/or data. In some embodiments, the electronic device  20  may not include wireless communications circuitry  25 . 
     A display  22  is also carried by the device housing  21  and is coupled to the controller  23 . The display  22  may be a liquid crystal display (LCD), for example, or may be another type of display, as will be appreciated by those skilled in the art. The display  22  may include glass or other materials, for example, that may deform when a localized force is applied thereto. The display  22  may also be in the form of a touch display, for example, and be responsive to user input or touching, as will be appreciated by those skilled in the art. 
     The electronic device  20  may also include additional and/or other types of input devices carried by the device housing  21 , for example, a pushbutton switch. The other and/or additional input devices may cooperate with the controller  23  to perform a device function in response to operation thereof. For example, a device function may include a powering on or off of the electronic device  20 , initiating communication via the wireless communications circuitry  25 , and/or performing a menu function. 
     The electronic device  20  also includes an actuator  30  coupled between the device housing  21  and the display  22 . The actuator  30  includes an actuator body  31  having an actuator bottom  32  and a sidewall  33  extending upwardly therefrom. The sidewall  33  illustratively has a cylindrical shape. The sidewall  33  may have another shape. The actuator body  31  may include a ferrous material, for example, ferrous steel. The actuator body  31  may include other and/or additional materials. For example, the actuator bottom  32  may include ferromagnetic material or non-ferromagnetic material, while the sidewall  33  may include ferromagnetic material. 
     The actuator  30  also includes a first guide member  40  that is carried by the actuator bottom  32  and is spaced inwardly from adjacent portions of the sidewall  33  to define a channel  35 . The first guide member  40  includes a body  41  having a passageway  42  therein. 
     A coil  36  is carried by the sidewall  33 . More particularly, the coil  36  is carried within the sidewall and is flush therewith. The coil  36  may include copper, for example. The coil  36  may include other and/or additional materials. Moreover, while a single coil  36  is illustrated, it should be understood that the actuator  30  may include more than one coil. 
     A magnet  34  is moveable within the channel  35 . The magnet  34  may be a permanent magnet, for example. The magnet  34  may be an NdFeB magnet, for example, and may be polarized in-plane, as will be appreciated by those skilled in the art. Of course, the magnet  34  may be another type of magnet. While the magnet  34  is illustrated in the form of a single magnet body, the magnet may be in the form of multiple magnetic segments or bodies. 
     The actuator  30  also includes an actuator top  37  coupled to the magnet  34 . The actuator top  37  illustratively includes a top plate  45  and a spacer  46  between the top plate and the magnet  34 . The sizing, for example, length of the spacer  46  may vary, as will be appreciated by those skilled in the art. The actuator top  37  also includes a second guide member  44  that cooperates with the first guide member  40 . The actuator top  37 , including the second guide member  44 , may include ferrous material and/or may be magnetic, for example. The actuator top  37  may include other and/or additional materials. The actuator top  37  may conceptually be considered a mass or force spreader, for example. 
     The second guide member  44  includes a projection  47  that is received within the passageway  42  of the body  41 . The first and second guide members  40 ,  44  provide or define a guide interface that may increase stabilization in the x-axis and y-axis directions, as will be appreciated by those skilled in the art. The guide interface provided by the first and second guide members  40 ,  44  may be considered a friction guided interface, for example. However, the first and second guide members  40 ,  44  may define a frictionless interface, in which case, with brief reference to  FIG. 5 , a biasing member  48 ′ may be carried within the passageway  42 ′ of the body  41 ′. The biasing member  48 ′ is illustratively in the form of a spring. However, other types of biasing members  48 ′ may be used or carried within the passageway  42 ′ of the body  41 ′. Additional biasing members  48 ′ may be used and/or the biasing members may be located elsewhere, for example, between the actuator top  37 ′ and the first guide member  40 ′ or sidewall  33 ′ and/or in the channel  35 ′. 
     It should be understood that while a particular arrangement of the first and second guide members  40 ,  44  is illustrated, there may be other arrangements or guiding techniques, for example, the second guide member may have a projection and the first guide member may have a passageway. Of course, the first and second guide members  40 ,  44  may not include a passageway and projection, but rather other and/or additional guides, such as, for example, tracks, guide members, etc. 
     The controller  23  is configured to drive the coil  36  to relatively move the actuator bottom  32  and actuator top  37  to thereby deform the display  22 . In other words, in operation, when haptic feedback is desired, the controller  23  drives the coil  36  so that the actuator top  37  moves away from or toward the bottom  32  of the actuator body  31  to apply a force, for example, from the backside, of the display  22  causing it to deform. If the controller  23  drives the coil  36  to move the actuator bottom  32  toward the actuator top  37  to thereby deform the display, it may be desirable that the actuator top be secured to the display  22 , for example, by adhesive or other bonding or securing techniques. When the display  22  is in the form of a touch display, the controller  23  may drive the coil  36  to move the actuator bottom  32  and the actuator top  37  to deform the display based upon input from the touch display, for example. 
     For example, the controller  23  may drive the coil  36  to move the actuator bottom  32  and actuator top  37  at a desired frequency to generate a desired force and type of haptic feedback. As will be appreciated by those skilled in the art, the waveform generated by the controller  23  for driving the actuator  30  determines the type of haptic feedback (e.g., how the feedback feels to a user). For example, the controller  23  may drive the actuator for a desired feedback (e.g., tap, vibe). The controller  23  may also drive the actuator  30  to deform the display  22  so that a user&#39;s finger when placed on the display adjacent the actuator, may feel as if there is a corresponding input device (e.g., pushbutton switch) by way of the deformation. Accordingly, when the display  22  is in the form of a touch display, user input adjacent the actuator  30  may perform functions, for example, of that of a “home” button. 
     Referring to  FIGS. 6-8  simulated magnetic flux lines  61 ,  62 ,  63  are illustrated.  FIG. 6  illustrates flux lines  61  with the coil  36  not being driven (i.e., coil off), which results in a net-zero force on the magnet  34 .  FIG. 7  illustrates magnetic flux lines  62  with the coil  36  being driven (i.e., coil on), which results in a net upward force on the magnet  34 , which relatively moves the actuator bottom  32  and actuator top  37  (i.e., moves the actuator bottom and top apart). TAs will be appreciated by those skilled in the art, force on the magnet  34  may be calculated from energy minimization. For example, F z =dU/dz, where U=integral (B 2 /2μ, dV).  FIG. 8  illustrates the flux lines  63  with the coil  36  being driven and the actuator top  37  being at a different position along its path of travel relative to its position in  FIG. 7 . As will be appreciated by those skilled in the art, the actuator  30  is based upon a reluctance motor principle, and not the Lorentz force, for example, that may be the basis for a voice coil motor. 
     As described above and illustrated in  FIGS. 6-8 , the magnetic field generated by the magnet  34  forms a loop in three-dimensional space, and thus, the field magnitude may be characterized by its magnetic flux density. Referring to  FIG. 9 , a portion of the flux  64  may leak beyond the actuator  30  and beyond the device housing  21 , potentially affecting nearby objects that may be sensitive to magnetic fields (e.g., credit cards, pacemakers). Accordingly, it may be desirable to control any undesired magnetic flux leakage. 
     To address the magnetic flux leakage, in some embodiments, the actuator top may be magnetic or include ferromagnetic material. Referring to  FIGS. 10 and 11 , simulated flux leakage in the xy-axis and z-axis planes with an actuator top that does not include magnetic or ferromagnetic material is illustrated.  FIGS. 12 and 13  illustrate simulated flux leakage in the xy-axis and z-axis planes with an actuator top that includes ferromagnetic material. It should be noted that the actuators that are the basis for the simulated flux lines in  FIGS. 12 and 13  are flipped or inverted relative to the corresponding simulated flux leakage in  FIGS. 10 and 11 .  FIGS. 14 and 15  illustrate simulated flux leakage in the xy-axis and z-axis planes with an actuator top that that includes magnetic material (i.e., is magnet-based). 
     Referring now to  FIGS. 16-18 , in another exemplary embodiment, another embodiment of an actuator  30 ″ is illustrated. The actuator  30 ″ may be carried within the device housing  21 ″ inverted or upside down relative to previously described embodiments. In other words, the actuator top  37 ″ and magnet  34 ″ may be positioned adjacent the device housing  21 ″ while the actuator body  31 ″, first guide member  40 ″, and coil  36 ″ are adjacent the display  22 ″ so as to be movable relative to the actuator top. In other words, conceptually, the actuator top  37 ″ may be considered stationary within the device housing  21 ″ and the actuator body  31 ″ along with the first guide member  40 ″ and the coil  36 ″ may be considered moving to deform the display  22 ″. 
     Additionally, a bearing insert  49 ″ may be carried within the passageway  42 ″ of the first guide member  40 ″. In other words, the bearing insert  49 ″ may be carried between the second guide member  44 ″ and the first guide member  40 ″ within the passageway  42 ″. The bearing insert  49 ″ maintains alignment during assembly, operation, or dropping of the actuator  30 ″. The actuator body  31 ″ and first guide member  40 ″ may be formed as a single or monolithic unit or may be in the form of multiple discrete segments. 
     The actuator top  37 ″ in the present embodiment may define a bottom plate that may be larger that the actuator body  31 ″ and may couple to a connector  26 ″, which may be flexible, and that includes connection points  27 ″ (e.g., solder points) ( FIGS. 17 and 18 ). 
     Referring additionally to  FIGS. 19 and 20 , simulated flux lines for the actuator  30 ″ with the coil  36 ″ off and on respectively are illustrated. The line  71 ″ in graph  70 ″ in  FIG. 21  illustrates simulated stroke versus actuation force (excluding friction) of the actuator  30 ″. 
     Referring now to the graph  72 ″ in  FIG. 22 , the actuator  30 ″ is naturally unstable, particularly in the z-direction, which may cause a “snapping” together of the actuator bottom  32 ″ and the actuator top  37 ″. The line  73 ″ illustrates stroke versus force with the coil  36 ″ enabled, while the line  74 ″ illustrates stroke versus force with the coil disabled. Thus, it may be desirable to add a restoring biasing member, for example, a spring, to bias the actuator apart or upwards and to limit the upward travel range. The line  75 ″ represents a desired stroke versus force. The lines  76 ″ and  77 ″ in the graph  78 ″ in  FIG. 23  illustrate stroke versus force with the coil  36 ″ enabled and disabled, respectively. A restoring biasing member or spring provides upward biasing so that a stable equilibrium occurs at about +0.8 mm. The line  80 ″ in the graph  79 ″ in  FIG. 24  illustrates stroke versus force with a stroke=0 corresponding to a nominal position. In this case, the coil  36 ″ and the magnet  34 ″ are aligned center-to-center in the z-axis direction. 
     Referring now to  FIGS. 25 and 26 , it may thus be desirable to add a restoring biasing member  83 ′″ (e.g., spring), in any one or more of several locations. For example, the restoring biasing member  83 ′″ may be added in any one or more of outside the sidewall  33 ′″ between the actuator top  37 ′″ and the actuator bottom  32 ′″, between the actuator top and the body  41 ′″ of the first guide member  40 ′″, and between the magnet  34 ′″ and the actuator body  31 ′″ or more particularly, the actuator bottom. Of course, any restoring biasing member  83 ′″ may be located elsewhere and be in different forms, for example, shapes and sizes. 
     Referring now to the graph  90 ′″ in  FIG. 27 , illustratively the in-plane restoring forces may be considered relatively modest. As previously described, the magnet  34 ′″ is relatively unstable in x/y/theta plane, and the bearing insert  49 ′″ or interface keeps the magnet aligned during assembly, operation, and blunt forces, for example, dropping. The in-plane forces are &lt;0.3 N for +/−50 um magnet offsets. Assuming a 20% static coefficient of friction, there is less than a 0.06 N force loss to friction. The lines  91 ′″,  92 ′″, and  93 ′″ illustrate z-offset as −345 microns, 0 microns, and 536 microns, respectively. 
     As will be understood by those skilled in the art, and in accordance with the embodiments described above, to achieve the relative movement of the actuator bottom  32  and the actuator top  37 , either of the actuator bottom or actuator top may be coupled to or carried by the device housing  21  or adjacent the display  22  so that either the actuator bottom or the actuator top may be considered, conceptually, moving relative to the other. 
     A method aspect is directed to a method of making an actuator  30  to be coupled between a device housing  21  and a display  22  of an electronic device  20 . The method includes forming an actuator body  31  having an actuator bottom  32  and a sidewall  33  extending upwardly therefrom. The method may also include positioning a first guide member  40  carried by the actuator bottom  32  and spaced inwardly from adjacent portions of the sidewall  33  to define a channel  35 , and positioning a coil  36  carried by the sidewall. The method also includes positioning a magnet  34  to be moveable within the channel  35 , and coupling an actuator top  37  to the magnet so that a second guide member  44  cooperates with the first guide member  40  and so that upon driving the coil  36 , the actuator top and the actuator bottom  32  relatively move to thereby deform the display  22 . 
     Referring now to  FIG. 28 , in another embodiment, the electronic device  120  also includes an actuator  130  coupled between the device housing and the display  122 . The actuator  130  includes an actuator body  131  having an actuator bottom  132  and a sidewall  133  extending upwardly therefrom. The sidewall  133  illustratively has a cylindrical shape or outline. The sidewall  133  may have another shape or outline, for example, rectangular. The actuator body  131  may include a ferrous material, for example, ferrous steel, in which case, the ferrous actuator body may operate as a magnetic field concentrator. The actuator body  131  may include other and/or additional materials. 
     A magnet  134  is carried by the actuator bottom  132  and is spaced inwardly from the sidewall  133  to define a channel  135 . The magnet  134  may be a permanent magnet, for example. The magnet  134  may be an NdFeB magnet, for example. Of course, the magnet  134  may be another type of magnet. A magnetic flux concentrator  138  or body is carried by the magnet  134 . The magnetic flux concentrator  138  may be ferrous or include ferrous material, for example. 
     A coil  136  is moveable within the channel  135 . The coil  136  may include copper, for example. The coil  136  may include other and/or additional materials. Moreover, while a single coil  136  is illustrated, it should be understood that the actuator  130  may include more than one coil. 
     The actuator  130  also includes an actuator top  137  coupled to the coil  136 . The actuator top  137  may include ferrous material and/or may be magnetic, for example. The actuator top  137  may include other and/or additional materials. The actuator top  137  may conceptually be considered a mass or force spreader, for example. 
     The controller  123  is configured to drive the coil  136  to relatively move the actuator bottom  132  and actuator top  137  to thereby deform the display  122 . In other words, in operation, when haptic feedback is desired, the controller  123  drives the coil  136  so that the actuator top  137  moves away from or toward the bottom  132  of the actuator body  131  to apply a force, for example, from the backside, of the display  122  causing it to deform. If the controller  123  drives the coil  136  to move the actuator bottom  132  toward the actuator top  137  to thereby deform the display, it may be desirable that the actuator top be secured to the display  122 , for example, by adhesive or other bonding or securing techniques. Alternatively, in some embodiments, the actuator top  137  may be biased against the display  122  by way of a biasing member, e.g., spring and/or other non-adhesive bonding technique. When the display  122  is in the form of a touch display, the controller  123  may drive the coil  136  to move the actuator bottom  132  and the actuator top  137  to deform the display based upon input from the touch display, for example. 
     For example, the controller  123  may drive the coil  136  to move the actuator bottom  132  and actuator top  137  apart at a frequency of about 250 Hz. Driving the actuator  130  at 250 Hz (e.g., direct or averaged) may provide increased feedback. 
     Of course, as will be appreciated by those skilled in the art, the waveform generated by the controller  123  for driving the actuator  130  determines the type of haptic feedback (e.g., how the feedback feels to a user). For example, the controller  123  may drive the actuator for a desired feedback (e.g., tap, vibe). The controller  123  may also drive the actuator  130  to deform the display  122  so that a user&#39;s finger when placed on the display adjacent the actuator, may feel as if there is a corresponding input device (e.g., pushbutton switch) by way of the deformation. Accordingly, when the display  122  is in the form of a touch display, user input adjacent the actuator  130  may perform functions, for example, of that of a “home” button. 
     Deformation of the display  122  of about 27 microns may correspond to a force of about 3 N-4 N for the electronic device  120 . However, the amount of force may correspond to the type of electronic device. The amount of force applied to the display  122  to obtain a desired amount of deformation may also be based upon the thickness or elastic modulus of the display. For example, for a thicker display  122  more energy may be used to obtain a desired deformation relative to a thinner display. The type of materials included in the display  122  may also affect the amount of force for deforming the display a given amount. Alternatively or additionally, a larger sized actuator  130  may be used. 
     Referring now additionally to  FIG. 29 , it may be desirable to control the magnetic flux generated by the actuator  130 . For example, a desired magnetic flux path  141  and undesired flux leakage  142  are illustrated. The magnetic field generated by the magnet  134  forms a loop in three-dimensional space. The field magnitude may be characterized by its magnetic flux density. A portion of the flux may leak beyond the actuator  130 , for example, and beyond the extent of or the desirable range of the electronic device  120 , which may potentially affect nearby objects that may be sensitive to magnetic fields (e.g., credit cards, pacemakers). Accordingly, it may be desirable to control any undesired magnetic flux leakage. 
     Referring now additionally to the diagrams in  FIGS. 30 and 31 , for example, where the actuator top  137  does not include a ferrous or magnetic material, magnetic flux leakage is illustrated. The magnetic flux density and magnetic flux streamlines  143  are illustrated in  FIG. 30 . 
     With respect to  FIG. 31 , the simulated in-plane flux density may be of particular interest for estimating the impact of flux leakage on adjacent devices. There may be a specific value for the maximum desirable in-plane flux leakage above ( 144 ) and below ( 145 ) the actuator  130 . As shown, the flux leakage is 240 G towards the front of the actuator  130 . The lines  150 ,  151 ,  152 ,  153 ,  154 ,  155 ,  156 ,  157 ,  158 , and  159  correspond to a flux leakage of 50, 100, 150, 250, 300, 350, 400, 450, and 500 G (i.e., |B xy |(G)), respectively. The corresponding force generation is 2.5 N with a figure of merit being 10.4 N/kG. 
     Referring now briefly to  FIG. 32 , in an embodiment where the actuator top  137 ′ is not ferrous or magnetic, to reduce flux leakage, the electronic device  120 ′ may include ferrous shielding bodies  161   a ′,  161   b ′ carried within the device housing  121 ′ adjacent the actuator  130 ′. While two ferrous shielding bodies  161   a ′,  161   b ′ are illustrated, those skilled in the art will appreciate that there may be any number of ferrous shielding bodies which may be carried within the device housing  121 ′ and spaced from the actuator  130 ′ to provide increased flux leakage control, for example. 
     Referring now to  FIG. 33 , in another embodiment, to further control or reduce undesirable flux leakage, the actuator top  137 ″ is magnetic. The polarization direction of the magnetic actuator top  137 ″ (i.e. shielding magnet) is oriented opposite from the magnet  134 ″, which results in destructive interference. In some applications, for example, audio at 20 kHz, using a moving actuator top  137 ″ may be not desirable. In lower bandwidth applications, for example, &lt;1 kHz for haptics, the actuator top  137 ″ or moving mass can be increased permitting it to be magnetic. A small gap  162 ″ between the magnet  134 ″ and magnetic actuator top  137 ″ along with opposing polarity provides a relatively large reduction in flux leakage. 
     Referring to the graph in  FIG. 34  simulated flux leakage of an actuator  130 ″ with a magnetic actuator top  137 ″ is illustrated. As shown the leakage is 1.4 G. The lines  170 ″,  171 ″,  172 ″,  173 ″,  174 ″,  175 ″,  176 ″,  177 ″,  178 ′, and  179 ″ correspond to a flux leakage of 50, 100, 150, 250, 300, 350, 400, 450, and 500 G (i.e., |B xy |(G)), respectively. The corresponding force generation is 2.9 N, with a figure of merit being 2071 N/kG. Indeed, by making the actuator top  137 ″ magnetic, force generation may be increased and flux leakage may be reduced by several orders of a magnitude. Maximum desirable in-plane flux leakage thresholds above ( 144 ″) and below ( 145 ″) the actuator  130 ″ are illustrated, for example, for comparison with an actuator without a magnetic actuator top ( FIG. 33 ). 
     Referring now to  FIG. 35 , in another embodiment, the actuator  130 ′″ includes a suspension system  147 ′″ that illustratively includes a base  148 ′″ and a suspension element  149 ′″ coupled between the base and the actuator top  137 ′″. The suspension system  147 ′″ may include polyetheretherketone (PEEK) or other material, and may operate as a damper, for example. 
     A method aspect is directed to a method of making an actuator  130  to be coupled between a device housing  121  and a display  122  of an electronic device  120 . The method includes forming an actuator body  131  having an actuator bottom  132  and a sidewall  133  extending upwardly therefrom and positioning a magnet  134  carried by the actuator bottom and spaced inwardly from adjacent portions of the sidewall to define a channel  135 . The method may also include positioning a coil  136  that is moveable within the channel  135  and coupling an actuator top  137  to the coil so that upon driving the coil, the actuator top and the actuator bottom  132  relatively move to thereby deform the display  122 . 
     While several exemplary embodiments have been described herein whereby the actuator top  37  is moved from the bottom to deform (e.g., is driven against or contact with) the display  22 , it should be appreciated by those skilled in the art that the actuator may be positioned so that the actuator body  31  is adjacent, in direct contact with, or otherwise deforms the display. In other words, the orientation of the actuator  30  with respect to the display  22  may be reversed. Moreover, it should be understood that there may be an intervening body, for example, between the actuator  30  and the display  22  so that the bottom  32  and actuator top  37  relatively moving causes the intervening body to deform the display. 
     Still further, while the electronic device  20  has been described with respect to a single actuator  30 , the electronic device may have more than one actuator. For example, the electronic device  20  may include an array of actuators spaced apart within the device housing  21 , and the controller may selectively operate each of the actuators in the array for a desired feel or type of feedback. 
     Many modifications and other embodiments of the invention will come to the mind of one skilled in the art having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. Therefore, it is understood that the invention is not to be limited to the specific embodiments disclosed, and that modifications and embodiments are intended to be included within the scope of the appended claims.

Metadata:
Filing Date: 20170418
Publication Date: 20180417
Grant Date: 20180417
Priority Date: 20161222
Inventors: DOLL, JOSEPH C.
SONGATIKAMAS, TEERA
MONKOWSKI, ADAM J.
GUPTA, PAVAN O.
Assignee: APPLE INC
CPC Classifications: [{"code": "H04M1/23", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01F7/064", "inventive": true, "first": true, "tree": "[]"}, {"code": "G06F1/163", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/0412", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/016", "inventive": true, "first": true, "tree": "[]"}, {"code": "G06F1/1626", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/016", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/016", "inventive": true, "first": true, "tree": "[]"}, {"code": "H05K5/0017", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/016", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01F7/064", "inventive": true, "first": false, "tree": "[]"}, {"code": "H05K5/0217", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04M1/23", "inventive": true, "first": false, "tree": "[]"}]
Family ID: 61872661