PATENT DOCUMENT

Publication Number: US-12212208-B2
Application Number: US-202016915504-A
Country: US
Kind Code: B2

Title: Haptic actuator including a field member having an opening receiving a stator therein and related methods

Abstract:
A haptic actuator may include a housing, and a stator fixed to a medial interior portion of the housing. The haptic actuator may also include a field member having an opening receiving the stator therein. The field member may include a frame and at least one permanent magnet carried by the frame. The haptic actuator may also include at least one flexure coupled between an end of the frame and adjacent interior portions of the housing to permit reciprocal movement of the field member within the housing responsive to the stator.

Claims:
That which is claimed is: 
     
       1. A haptic actuator, comprising:
 a housing; 
 a stator coupled to a medial interior portion of the housing; 
 a field member within the housing and defined by an axis of travel relative to the stator and a centerline perpendicular to the axis of travel, the field member comprising:
 a frame having an interior and an exterior, the interior defining an opening receiving the stator therein; 
 at least one permanent magnet carried by the frame and disposed within the opening defined by the interior of the frame; and 
 a sense magnet attached to the exterior of the frame and offset relative to the centerline, the sense magnet polarized along the axis of travel of the field member such that a surface of the sense magnet is perpendicular to the axis of travel; 
 
 a flexible circuit substrate attached to an exterior of the housing and carrying a Hall effect sensor that extends through the housing, the Hall effect sensor offset relative to the centerline and positioned adjacent to, and spaced apart from, the sense magnet, the Hall effect sensor configured to output a signal related to a position of the field member within the housing; 
 a ferritic stiffener coupled to the flexible circuit substrate and aligned with the Hall effect sensor; and 
 at least one flexure coupled between an end of the frame and adjacent interior portions of the housing to permit reciprocating longitudinal movement of the field member within the housing responsive to the stator. 
 
     
     
       2. The haptic actuator of  claim 1 , wherein the stator comprises a core and a plurality of serially coupled coils surrounding the core. 
     
     
       3. The haptic actuator of  claim 1 , wherein the at least one permanent magnet comprises a first permanent magnet on a first side of the opening and a second permanent magnet on a second side of the opening opposite the first side of the opening. 
     
     
       4. The haptic actuator of  claim 3 , wherein the first permanent magnet defines a first plurality of alternating magnetic poles, and the second permanent magnet defines a second plurality of alternating magnetic poles oriented in alignment with the first plurality of alternating magnetic poles. 
     
     
       5. The haptic actuator of  claim 3 , wherein the first permanent magnet defines a first plurality of alternating magnetic poles, and the second permanent magnet defines a second plurality of alternating magnetic poles oriented in opposite directions with the first plurality of alternating magnetic poles. 
     
     
       6. The haptic actuator of  claim 1 , wherein the at least one permanent magnet defines a plurality of magnetic poles arranged in a Halbach array. 
     
     
       7. The haptic actuator of  claim 1 , further comprising a ferritic body between the at least one permanent magnet and the frame. 
     
     
       8. The haptic actuator of  claim 1 , wherein the at least one flexure has a wishbone shape and comprises two diverging arms joined together at proximal ends and having spaced distal ends operatively coupled between the adjacent interior portions of the housing and the end of the field member, respectively. 
     
     
       9. The haptic actuator of  claim 1 , wherein the housing comprises a non-ferritic material. 
     
     
       10. The haptic actuator of  claim 1 , wherein the frame comprises tungsten. 
     
     
       11. The haptic actuator of  claim 1 , further comprising at least one resilient stop member carried by the frame within the opening. 
     
     
       12. An electronic device, comprising:
 a device housing; 
 wireless communications circuitry carried by the device housing; 
 a haptic actuator comprising:
 an actuator housing, 
 a stator coupled to a medial interior portion of the actuator housing; 
 a field member within the actuator housing and having a frame that defines a first opening and an axis of travel, the first opening receiving the stator therein, the field member further comprising at least one permanent magnet carried by the frame and disposed within the first opening defined by the frame; 
 a sense magnet attached to an exterior of the frame, the sense magnet polarized along the axis of travel and offset relative to a centerline of the field member that is perpendicular to the axis of travel, the axis of travel perpendicular to a surface of the sense magnet; and 
 at least one flexure coupled between an end of the frame and adjacent interior portions of the actuator housing to permit reciprocating longitudinal movement of the field member within the actuator housing responsive to the stator; 
 
 a flexible circuit substrate attached to an exterior of the device housing and carrying a Hall effect sensor that extends into a second opening in the actuator housing, the Hall effect sensor adjacent and spaced apart from the sense magnet and configured to output a signal related to a position of the field member within the actuator housing; 
 a ferritic stiffener coupled to the flexible circuit substrate and aligned with the Hall effect sensor; and 
 a controller configured to perform a wireless communications function in cooperation with the wireless communications circuitry and selectively operate the haptic actuator. 
 
     
     
       13. The electronic device of  claim 12 , wherein the stator comprises a core and a plurality of serially coupled coils surrounding the core. 
     
     
       14. The electronic device of  claim 12 , wherein the at least one permanent magnet comprises a first permanent magnet on a first side of the first opening and a second permanent magnet on a second side of the first opening opposite the first side of the first opening. 
     
     
       15. The electronic device of  claim 14 , wherein the first permanent magnet defines a first plurality of alternating magnetic poles, and the second permanent magnet defines a second plurality of alternating magnetic poles oriented in alignment with the first plurality of alternating magnetic poles. 
     
     
       16. The electronic device of  claim 14 , wherein the first permanent magnet defines a first plurality of alternating magnetic poles, and the second permanent magnet defines a second plurality of alternating magnetic poles oriented in opposite directions with the first plurality of alternating magnetic poles. 
     
     
       17. The electronic device of  claim 12 , wherein the at least one permanent magnet defines a plurality of magnetic poles arranged in a Halbach array. 
     
     
       18. A method of making a haptic actuator, the method comprising:
 mounting a stator to a medial interior portion of a housing; 
 mounting a field member within the housing using at least one flexure, the field member having a frame, the frame having an interior and an exterior, the interior defining an opening that receives the stator to permit reciprocating longitudinal movement of the field member along an axis of travel and within the housing responsive to the stator, and the field member having at least one permanent magnet carried by the frame and disposed within the opening defined by the interior of the frame; 
 attaching a sense magnet polarized along the axis of travel of the field member to the exterior of the frame offset relative to a centerline of the field member that is perpendicular to the axis of travel; 
 attaching a flexible circuit substrate to an exterior of the housing, the flexible circuit substrate carrying a Hall effect sensor, the attachment of the flexible circuit substrate to the exterior of the housing causing the Hall effect sensor to extend through the housing and be positioned adjacent and spaced apart from the sense magnet; 
 a ferritic stiffener coupled to the flexible circuit substrate and aligned with the Hall effect sensor; and 
 in accordance with a signal output of the Hall effect sensor, determining a position of the field member within the housing. 
 
     
     
       19. The method of  claim 18 , wherein the stator comprises a core and a plurality of serially coupled coils surrounding the core. 
     
     
       20. The method of  claim 18 , wherein the at least one permanent magnet comprises a first permanent magnet on a first side of the opening, and a second permanent magnet on a second side of the opening opposite the first side of the opening. 
     
     
       21. The method of  claim 20 , wherein the first permanent magnet defines a first plurality of alternating magnetic poles, and the second permanent magnet defines a second plurality of alternating magnetic poles oriented in alignment with the first plurality of alternating magnetic poles. 
     
     
       22. The method of  claim 20 , wherein the first permanent magnet defines a first plurality of alternating magnetic poles, and the second permanent magnet defines a second plurality of alternating magnetic poles oriented in opposite directions with the first plurality of alternating magnetic poles.

Description:
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 
     A haptic actuator may include a housing and a stator coupled to a medial interior portion of the housing. The haptic actuator may also include a field member having an opening receiving the stator therein. The field member may include a frame and at least one permanent magnet carried by the frame. The haptic actuator may also include at least one flexure coupled between an end of the frame and adjacent interior portions of the housing to permit reciprocal movement of the field member within the housing responsive to the stator. 
     The stator may include a core and a plurality of serially coupled coils surrounding the core. The at least one permanent magnet may include a first permanent magnet on a first side of the opening, and a second permanent magnet on a second side of the opening opposite the first side of the opening, for example. 
     The first permanent magnet may define a first plurality of alternating magnetic poles, and the second permanent magnet may define a second plurality of alternating magnetic poles oriented in alignment with the first plurality of alternating magnetic poles. Alternatively, the first permanent magnet may define a first plurality of alternating magnetic poles, and the second permanent magnet may define a second plurality of alternating magnetic poles oriented in opposite directions with the first plurality of alternating magnetic poles, for example. 
     The at least one permanent magnet may define a plurality of magnetic poles arranged in a Halbach array, for example, in other embodiments. The haptic actuator may also include a ferritic body between the at least one permanent magnet and the frame. 
     The haptic actuator may also include a Hall effect sensor carried by the housing and configured to sense a position of the field member. The at least one flexure may have a wishbone shape and may include two diverging arms joined together at proximal ends and having spaced distal ends operatively coupled between the adjacent portions of the housing and the end of the field member, respectively, for example. 
     The housing may include a non-ferritic material. The frame may include tungsten, for example. The haptic actuator may also include at least one resilient stop member carried by the frame within the opening, for example. 
     A method aspect is directed to a method of making a haptic actuator. The method may include mounting a stator to a medial interior portion of a housing. The method may also include mounting a field member, including a frame and at least one permanent magnet carried by the frame, within the housing using at least one flexure so that the stator is received within an opening in the field member to permit reciprocal movement of the field member within the housing responsive to the stator. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a schematic diagram of an electronic device including a haptic actuator in accordance with an embodiment. 
         FIG.  2    is a schematic block diagram of the electronic device of  FIG.  1   . 
         FIG.  3    is an exploded view of a haptic actuator in accordance with an embodiment. 
         FIG.  4    is a partially exploded view of the haptic actuator of  FIG.  3   . 
         FIG.  5    is a top schematic view of a haptic actuator in accordance with an embodiment. 
         FIG.  6    is a schematic diagram of an exemplary magnetic pole orientation of permanent magnets of a haptic actuator in accordance with another embodiment. 
         FIG.  7    is a schematic diagram of an exemplary magnetic pole orientation of permanent magnets of a haptic actuator in accordance with another embodiment. 
         FIG.  8    is a schematic diagram of an exemplary magnetic pole orientation of permanent magnets of a haptic actuator in accordance with another embodiment. 
         FIG.  9    is a schematic diagram of an exemplary coil positioning relative to the core in accordance with an embodiment. 
         FIG.  10    is another schematic diagram of an exemplary coil positioning relative to the core in accordance with an embodiment. 
         FIG.  11    is another schematic diagram of an exemplary magnet transition zone positioning relative to the core recess in accordance with an embodiment. 
         FIG.  12    is another diagram of an exemplary magnet transition zone positioning relative to the core recess in accordance with an embodiment. 
         FIG.  13    is a partially exploded view of a haptic actuator in accordance with an embodiment. 
         FIG.  14    is a schematic top view of a portion of the haptic actuator of  FIG.  13   . 
         FIG.  15    is a schematic diagram of a portion of a haptic actuator in accordance with another embodiment. 
         FIG.  16    is a schematic diagram of the permanent magnets of the haptic actuator of  FIG.  15   . 
         FIG.  17    is a schematic diagram of a haptic actuator in accordance with 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 notation and numbers in increments of 100 are used to indicate similar elements in alternative embodiments. 
     Referring initially to  FIGS.  1 - 2   , an electronic device  20  illustratively includes a device housing  21  and a controller  22  carried by the device housing. The electronic device  20  is illustratively a mobile wireless communications device, for example, a cellular telephone or smartphone. The electronic device  20  may be another type of electronic device, for example, a wearable device (e.g., a watch), a tablet computer, a laptop computer, etc. 
     Wireless communications circuitry  25  (e.g. cellular, WLAN, Bluetooth, etc.) is also carried within the device housing  21  and coupled to the controller  22 . The wireless communications circuitry  25  cooperates with the controller  22  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  23  is also carried by the device housing  21  and is coupled to the controller  22 . The display  23  may be, for example, a light emitting diode (LED) display, a liquid crystal display (LCD), or may be another type of display, as will be appreciated by those skilled in the art. The display  23  may be a touch display and may cooperate with the controller  22  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  illustratively includes a haptic actuator  40 . The haptic actuator  40  is coupled to the controller  22  and provides haptic feedback to the user in the form of relatively long and/or short vibrations. The vibrations may be indicative of a message received, and the duration and type of the vibration may be indicative of the type of message received. Of course, the vibrations may be indicative of or convey other types of information. 
     While a controller  22  is described, it should be understood that the controller  22  may include one or more of a processor and other circuitry to perform the functions described herein. For example, the controller  22  may include a class-D amplifier to drive the haptic actuator  40  and/or sensors for sensing voltage and current. 
     Referring now additionally to  FIGS.  3 - 5    the haptic actuator  40  includes a housing, for example, an elongate housing  41  that defines a lengthwise axis  48  ( FIG.  5   ). The elongate housing  41  may be metal, for example, stainless steel or other non-ferritic material. The elongate housing  41  may be another type of material or include more than one type of material. The elongate housing  41  has opposing ends  42   a ,  42   b  and opposing sides  43   a ,  43   b . The elongate housing  41  illustratively has a dimension in a length direction greater than a width direction (e.g., x-axis travel direction). The elongate housing  41  illustratively includes frame segments  49   a ,  49   b  defining sides (e.g., having an L-shape), a bottom plate  49   c , and a cover  49   d . A label cover  49   e  may also be carried by the cover  49   d  of the elongate housing  41 . Brackets  49   f - 49   h , for example, for mounting, are coupled to the frame segments  49   a ,  49   b . Of course, the elongate housing  41  may include other and/or additional components may be formed as a monolithic unit. While an elongate housing  41  is described, it should be appreciated by those skilled in the art that the actuator housing may be another shape, for example, square. 
     The haptic actuator  40  also includes a stator  46  coupled to a medial interior portion of the elongate housing  41 . The stator  46  illustratively includes a core  47  and serially coupled coils  44 ,  45  surrounding the core. While two serially coupled coils  44 ,  45  are illustrated, it will be appreciated by those skilled in the art that there may be any number of coils, for example, one or more than two, and the coils may be coupled in parallel and/or serially. 
     The haptic actuator  40  also includes a field member  50  within the elongate housing  41 . The field member  50 , similarly to the elongate housing  41 , has opposing ends  53   a ,  53   b  and opposing sides  54   a ,  54   b  extending therebetween ( FIG.  5   ). The field member  50 , similarly to the elongate housing  41 , has a dimension in a length direction greater than a width direction. Thus, the field member  50  is reciprocally movable in the length direction (i.e., the x-axis direction). While the movement of the field member  50  is described as being moveable in one direction, i.e., a linear haptic actuator, it should be understood that in some embodiments, the field member may be movable in other directions, i.e., an angular haptic actuator, or may be a combination of both a linear and an angular haptic actuator. 
     The field member  50  includes a frame  57 . The frame  57  may define a mass or moveable mass, for example. The frame  57  may include tungsten, for example. The frame  57  may be a different material (e.g., relatively heavy material). In some embodiments, the field member  50  may include discrete masses instead of the frame  57  defining a mass. 
     The field member  50 , and more particularly, the frame  57  has an opening  55  therein. The stator  46  is received within the opening  55 . 
     The field member  50  also includes permanent magnets  51   a ,  51   b  carried by the frame  57 . The permanent magnets  51   a ,  51   b  may be neodymium, for example. The permanent magnets  51   a ,  51   b  are illustratively elongate, similar to the elongate housing  41 . More particularly, a first permanent magnet  51   a  is carried within the opening  55  on a first side of the opening, and a second permanent magnet  51   b  is carried within the opening on a second side of the opening. 
     Referring additionally to  FIG.  6   , in an embodiment, the first permanent magnet  51   a ′ defines first alternating magnetic poles  58   a f. The second permanent magnet  51   b ′ defines second alternating magnetic poles  58   b ′ that are oriented in alignment with the first plurality of alternating magnetic poles. A transition zone  85  may be between adjacent alternating magnetic poles  58   a ,  58   b  ( FIG.  5   ). The permanent magnets  51   a f,  51   b ′ may positioned in different directions with respect to their respective poles, for example. The present embodiment includes a single coil where current flows out of the page O 1  with respect to a first half of the single coil  44 ′ or first half of the coil loop, while current flows into the page X 1  with respect to the second half of the single coil  45 ′ or the second half of the coil loop ( FIG.  6   ). 
     Referring briefly to  FIG.  7   , in another embodiment the magnetic poles  58   a ″,  58   b ″ of the first and second permanent magnets  51   a ″,  51   b ″ are oriented in opposite directions. Illustratively, current flows out of the page O 1  adjacent the first permanent magnet  51   a ″ and into the page X 1  adjacent the second permanent magnet  51   b ″ as it relates to the first coil  44 ″. Current flows into the page X 2  adjacent the first permanent magnet  51   a ″ and out of the page O 2  adjacent the second permanent magnet  51   b ″ as it relates to the second coil  45 ″. 
     Referring now to  FIG.  8   , in another embodiment, the magnetic poles  58   a ′″,  58   b ′″ of the first and second magnets  51   a ′″,  51   b ′″ are arranged in a Halbach array. The present embodiment includes a single coil where current flows out of the page O 1  with respect to a first half of the single coil  44 ′″ or first half of the coil loop, while current flows into the page X 1  with respect to the second half of the single coil  45 ′″ or the second half of the coil loop. 
     Referring again to  FIGS.  3 - 5   , a respective ferritic body  68   a ,  68   b  is between the permanent magnets  51   a ,  51   b  and the frame  57 . In some embodiments, ferritic bodies  68   a ,  68   b  may not be used. 
     A Hall effect sensor  81  is also illustratively carried by the elongate housing  41 . The Hall effect sensor  81  is carried by a flexible circuit substrate  83  that is coupled to a bottom of the elongate housing  41 . The Hall effect sensor  81  senses a position of the field member  50  such that the controller  22  may drive the haptic actuator  40  based upon the sensed positon of the field member, as will be appreciated by those skilled in the art. Other and/or additional sensors or sensor types and techniques may be used to determine a location or position of the field member  50 . In some embodiments, no Hall effect sensor  81  or other sensor for sensing of the position of the field member  50  may be used. Of course, other and/or additional sensors, such as, for example, motion sensors and strain sensors, may be used as a basis for driving the haptic actuator  40 . 
     Respective first and second resilient stop members  82   a ,  82   b  are carried by the frame  57  within the opening  55 . More particularly, the first and second resilient stop members  82   a ,  82   b  are carried within the opening  55  on first and second ends of the opening adjacent the longitudinal ends of the stator  46 . The first and second resilient stop members  82   a ,  82   b  may define crash stops for the field member  50 , for example. In some embodiments, the first and second resilient stop members  82   a ,  82   b  may be coupled to the stator  46 . 
     The first and second resilient stop members  82   a ,  82   b  may include thermoplastic, for example, and may be coupled within the opening  55  on the first and second ends by way of pressure sensitive adhesive. In other embodiments, the first and second resilient stop members  82   a ,  82   b  may include other and/or additional materials and may be coupled to the frame  57  within the opening  55  using other techniques. In some embodiments, first and second resilient stop members  82   a ,  82   b  may not be used and/or any number of stop members may be used. 
     The haptic actuator  40  also includes respective flexures  60  coupling each of first and second ends  53   a ,  53   b  of the field member  50  to be reciprocally movable within the elongate housing  41 . More particularly, the flexures  60  are each coupled between an end of the frame  57  and an adjacent interior portion (i.e., ends  42   a ,  42   b  of the elongate housing  41 ) to permit reciprocal movement of the field member  50  along the lengthwise axis  48  within the elongate housing responsive to the stator  46 . 
     Each flexure  60  illustratively has a wishbone or Y-shape, with two diverging arms  62   a ,  62   b  joined together at proximal ends. The two diverging arms  62   a ,  62   b  have spaced distal ends operatively coupled between adjacent portions of the field member  50  and the elongate housing  41 . 
     A bend  78  joins together the two diverging arms  62   a ,  62   b  at the proximal ends. The bend  78  causes the two diverging arms  62   a ,  62   b  to be spaced apart at the distal ends. While an example flexure  60  is illustrated, each flexure may have a different shape and more than one flexure may be used. For example, as will be appreciated by those skilled in the art, the haptic actuator  40 , and more particularly, the geometry of each flexure  60  may satisfy desired stress and stiffness metrics relative to other flexure geometries, particularly under a relatively confined space under a specified amplitude of travel displacement for haptic applications. 
     A mechanical stop  73  is carried by the distal end of one of the diverging arms  62   a . The mechanical stop  73  may include an elastomeric material, for example. The mechanical stop  73  may be carried by the other diverging arm  62   b.    
     Anchor members  79   a ,  79   b  are illustratively coupled between each flexure  60  and the adjacent end  42   a ,  42   b  of the elongate housing  41  and each flexure and an adjacent end  53   a ,  53   b  of the field member  50 , respectively. More particularly, the anchor members  79   a ,  79   b  are coupled between a distal end of an arm  62   a  and the end  42   a ,  42   b  of the elongate housing  41 , and a distal end of another arm  62   b  and the end  53   a ,  53   b  of the field member  50 . 
     A method aspect is directed to a method of making a haptic actuator  40 . The method includes mounting a stator  46  to a medial interior portion of a housing  41 . The method also includes mounting a field member  50 , including a frame  57  and at least one permanent magnet  51   a ,  51   b  carried by the frame, within the housing  41  using at least one flexure  60  so that the stator  46  is received within an opening  55  in the field member  50  to permit reciprocal movement of the field member, for example along the lengthwise axis  48  within the housing responsive to the stator  46 . 
     Referring now to  FIGS.  9 - 12   , in other embodiments, the actuator may include flared or flanged magnetic pole tips going over the coils. This may provide improved force characteristics, for example, by exhibiting a more linear behavior. Illustratively, the coils  144 ,  145  are wound around the core  147 , and more particularly within cavities or recesses within the core so that a portion of the coils are exposed through openings  159   a ,  159   b  in the core. The first opening  159   a  is centered relative to the corresponding cavity, and the first coil  144  is carried with the corresponding cavity. The second opening  159   b  is laterally offset relative to the corresponding cavity toward an adjacent end of the core  147 . The second coil  145  is carried within the corresponding cavity. The position of the cavities or recesses and openings  159   a ,  159   b , for example, relative to transition zones  193   a ,  193   b  of the permanent magnets  151   a ,  151   b  (i.e., areas between adjacent different polarities) defines force curves or alters the performance or force characteristics of the field member, and more particularly, how the stator  146  “appears” to the permanent magnets  151   a ,  151   b . In other words, by controlling the offset between the first and second openings  159   a ,  159   b  and the transition zones  193   a ,  193   b  of the permanent magnets  151   a ,  151   b , desired force characteristics may be achieved. 
     Similar to embodiments described above, the magnetic poles  158   a ,  158   b  of the first and second permanent magnets  151   a ,  151   b  are oriented in opposite directions, and current flows out of the page O 1  adjacent the first permanent magnet and into the page X 1  adjacent the second permanent magnet as it relates to the first coil  144 . Current flows into the page X 2  adjacent the first permanent magnet  151   a  and out of the page O 2  adjacent the second permanent magnet  151   b  as it relates to the second coil  145 . 
     As illustrated in  FIG.  10   , for example, the less of the coils  144 ′,  145 ′ that are exposed (i.e., the more of the coils that are within the cavity), the less of a jump there may be between magnetic poles  158   a ′,  158   b ′. In other words, there may be less resistance to moving the field member because to the permanent magnets  151   a ′,  151   b ′ the core  147 ′ and coils  144 ′,  145 ′ appear as one piece of material, and thus less ripples are generated during operation. 
     Other arrangements with respect to the positioning of the coils are illustrated in  FIGS.  11  and  12    to achieve desired operational characteristics. For example, a single permanent magnet  151 ″ may pass through the stator  146 ″, and more particularly, the coils  144 ″,  145 ″ ( FIG.  11   ). In another embodiment, the first opening  159   a ′″ in the core  147 ′″ is centered relative to its corresponding recess within the core. In contrast to the first opening  159   a ′″, the second opening  159   b ′″ in the core  147 ′″ is “offset” relative to its corresponding recess within the core. Elements illustrated, but not specifically described are similar to those described above. 
     As will be appreciated by those skilled in the art, the flanged arrangements in  FIGS.  9 - 12    may reduce the pole-to-pole distance, which may in turn reduce cogging forces (i.e., a passive force generated based upon interaction between the magnet and the core) and improve overall force characteristics. Additionally, the flanged poles described above may be formed by way of metal injection. Of course, the flanged poles may be fabricated using other techniques or methods, for example, flanges may be added by attaching a secondary piece to the stator post coil winding. Still further, the pole-to-pole transition voids may be offset, for example, symmetrically, to achieve desired performance characteristics. The pole-to-pole transition voids may be non-vertical or curved, for example. 
     Referring now to  FIGS.  13  and  14   , in another embodiment, the elongate housing  241  includes a “tub” housing  249   a  rather than discrete frame segments that couples to a bottom plate  249   c . The label cover  249   e  is carried by the top or cover portion of the housing  249   a . Additionally, a stiffener  271 , for example a ferritic stiffener, may be carried by a flexible circuit substrate  283 , which may be coupled to adjacent portions of the housing  249   a  by way of a pressure sensitive adhesive layer  272  and a heat activated film adhesive  274 , for example. The stiffener  271  may carry the Hall effect sensor  281 , as described above, for example, to measure fields in the direction normal to the path of travels and pointing toward the magnet. The stiffener  271  may provide magnetic shielding from outside aggressor fields and may improve mechanical robustness of the Hall effect sensor  281 . A thermistor  275  may also be carried by the flexible circuit substrate  283  and be coupled to a controller for temperature based operation of the haptic actuator, for example, based upon coil temperature. A recess or channel  266  is within the stator  246 , and more particularly, the core  247 , and the field member  250  to permit wiring from the coils  244 ,  245  and the thermistor  275  to pass through. 
     Additionally, a sense magnet  276  is illustratively carried by the field member  250  in a recess  277 . The sense magnet  276  is polarized in the elongated direction of the field member  250  or haptic actuator  240 . The sense magnet  276  may be used in conjunction with the Hall effect sensor  281  to determine a position of the field member  250 . Of course, the sense magnet  276  may be used for other and/or additional functions. 
     Elements illustrated but not specifically described are similar to those described above, for example, the ferritic bodies  268   a ,  268   b , the brackets  249   g ,  249   h , the mechanical stops  273 , the flexures  260  including the two diverging arms  262   a ,  262   b  and bend  278 , and anchor members  279   a ,  279   b.    
     Referring now to  FIGS.  15  and  16   , in an embodiment, the permanent magnets  351   a ,  351   b , which are, similar to the embodiments described above, on first and second opposing sides of the opening in the field member, each have side-by-side magnetic segments  391   a - 391   d ,  392   a - 392   d  having alternating magnetic polarizations. The side-by-side magnetic segments  391   a - 391   d  of the first permanent magnet  351   a  have opposite polarizations with respect to the side-by-side magnetic segments  392   a - 392   d  of the second permanent magnet  351   b.    
     The magnetic polarization transition zone  393   a  between the first and second adjacent segments  391   a ,  391   b  of the first permanent magnet  351   a  is non-vertical. While an angle from normal to a surface of the first permanent magnet  351   a  is illustrated, those skilled in the art will appreciate that the non-vertical angle may be any angle, for example, from three degrees from normal, and more particularly, from three degrees to twenty degrees from normal, such as seventeen degrees. The magnetic polarization transition zone  393   b  between the second and third adjacent segments  391   b ,  391   c  of the first permanent magnet  351   a  is vertical so that the first and second magnetic segments  391   a ,  391   b  each has a trapezoidal shape. The magnetic polarization transition zone  393   c  between the third and fourth adjacent segments  391   c ,  391   d  of the first permanent magnet  351   a  is also non-vertical so that the third and fourth magnetic segments each also has a trapezoidal shape. Of course, the magnetic transition zones  393   a - 393   c  can vary between vertical and non-vertical. The arrangement of the polarization transition zones  394   a - 394   c  between the magnetic segments  392   a - 392   d  of the second permanent magnet are illustratively matched with respect to non-vertical and vertical, however, in some embodiments, the non-vertical angles from normal need not match or may be different. 
     While the transition zones  393   a - 393   c ,  394   a - 394   c  are illustratively linear, the transition zones may be curved. The non-vertical magnetic polarization transition zones  393   a - 393   c ,  394   a - 394   c  may create forces in axes other than an axis of the desired direction of travel. For example, while in most cases, the magnetic polarization transition zones  393   a - 393   c ,  394   a - 394   c  may each have independent shapes, it may be particularly desirable to have the magnetic polarization transition zones on opposing sides (i.e., of the stator  346 ) cancel or reduce the forces on other axes. 
     A method aspect is directed to a method of making a haptic actuator  340 . The method includes mounting a stator  346  to a medial interior portion of a housing  341 . The method also includes mounting a field member  350 , including a frame  357  and at least one permanent magnet  351   a ,  351   b  carried by the frame, within the housing  341  so that the stator  346  is received within an opening  355  in the field member. The at least one permanent magnet  351   a ,  351   b  includes a plurality of side-by-side magnetic segments  391   a - 391   d ,  392   a - 392   d  having alternating magnetic polarizations with at least one non-vertical magnetic polarization transition zone  393   a - 393   c ,  394   a - 394   c  between adjacent magnetic segments. 
     Referring now to  FIG.  17   , in another embodiment, the magnetic polarization transition zones  393   a ′- 393   c ′,  394   a ′- 394   c ′ between adjacent magnetic segments  391   a ′- 391   d ′,  392   a ′- 392   d ′ are illustratively offset relative to the pole center. For example, the magnetic polarization transition zones  393   a ′- 393   c ′,  394   a ′- 394   c ′ may be offset by a quarter of a pole width. Of course, the offset may be different widths. While in most embodiments, the offsets of each magnetic polarization transition zone  393   a ′- 393   c ′,  394   a ′- 394   c ′ may be independently adjusted or modified, however, it may be desirable have offsets that are symmetrical to reduce or avoid any asymmetry in the force characteristics. 
     While several embodiments have been described herein, it should be appreciated by those skilled in the art that any element or elements from one or more embodiments may be used with any other element or elements from any other embodiment or embodiments. 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: 20200629
Publication Date: 20250128
Grant Date: 20250128
Priority Date: 20200629
Inventors: AMIN-SHAHIDI, DARYA
CHEN, DENIS G.
LEE, ALEX M.
RIDEL, SCOTT D.
Assignee: APPLE INC
CPC Classifications: [{"code": "H02K33/18", "inventive": true, "first": false, "tree": "[]"}, {"code": "B06B1/045", "inventive": false, "first": false, "tree": "[]"}, {"code": "B06B1/045", "inventive": true, "first": false, "tree": "[]"}, {"code": "H02K33/12", "inventive": true, "first": true, "tree": "[]"}, {"code": "H02K33/16", "inventive": true, "first": true, "tree": "[]"}, {"code": "B06B1/045", "inventive": false, "first": false, "tree": "[]"}, {"code": "H02K33/18", "inventive": true, "first": false, "tree": "[]"}, {"code": "H02K33/12", "inventive": true, "first": true, "tree": "[]"}]
Family ID: 79030463