PATENT DOCUMENT

Publication Number: US-10281984-B1
Application Number: US-201815964189-A
Country: US
Kind Code: B1

Title: Haptic actuator including sidewall clearance restricting feature and related methods

Abstract:
A haptic actuator may include a housing having opposing ends and opposing sides extending therebetween. The haptic actuator may also include at least one coil carried by the housing and a field member having opposing ends and opposing sides extending therebetween. The haptic actuator may also include a respective flexure coupling each end of the field member to an adjacent end of the housing so that the field member is reciprocally movable within the housing responsive to the at least one coil over an operating range and while maintaining a respective sidewall clearance between each side of the field member and an adjacent side of the housing. At least one sidewall clearance restricting feature may be configured to restrict the sidewall clearance when the field member moves beyond the operating range when subject to mechanical shock.

Claims:
That which is claimed is: 
     
       1. A haptic actuator comprising:
 a housing having opposing ends and opposing sides extending therebetween; 
 at least one coil carried by the housing; 
 a field member having opposing ends and opposing sides extending therebetween; 
 a respective flexure coupling each end of the field member to an adjacent end of the housing so that the field member is reciprocally movable within the housing responsive to the at least one coil over an operating range and while maintaining a respective sidewall clearance between each side of the field member and an adjacent side of the housing; and 
 at least one sidewall clearance restricting feature configured to restrict the sidewall clearance when the field member moves beyond the operating range when subject to mechanical shock. 
 
     
     
       2. The haptic actuator of  claim 1  wherein the at least one sidewall clearance restricting feature comprises at least one protruding body carried by the housing and extending within the respective sidewall clearance. 
     
     
       3. The haptic actuator of  claim 2  wherein the field member has a recess therein adjacent the at least one protruding body. 
     
     
       4. The haptic actuator of  claim 2  wherein the housing comprises metal; and wherein the at least one protruding body comprises an at least one stamped metal protruding body. 
     
     
       5. The haptic actuator of  claim 1  wherein the at least one sidewall clearance restricting feature comprises at least one protruding body carried by the field member and extending within the respective sidewall clearance. 
     
     
       6. The haptic actuator of  claim 5  wherein the housing has a recess therein adjacent the at least one protruding body. 
     
     
       7. The haptic actuator of  claim 1  wherein each respective flexure has a wishbone shape and comprises two diverging arms joined together at proximal ends and having spaced distal ends operatively coupled between adjacent ends of the field member and the housing. 
     
     
       8. The haptic actuator of  claim 7  wherein each respective flexure has a bend therein joining together the two diverging arms at the proximal ends. 
     
     
       9. The haptic actuator of  claim 1  further comprising a respective at least one anchor member coupled to an adjacent end of the housing and spaced apart from an adjacent end of the field member. 
     
     
       10. The haptic actuator of  claim 9  wherein each respective flexure is coupled between the respective at least one anchor member and the field member. 
     
     
       11. The haptic actuator of  claim 1  wherein the field member comprises at least one permanent magnet adjacent the at least one coil. 
     
     
       12. An electronic device comprising:
 a housing; 
 wireless communications circuitry carried by the housing; 
 a haptic actuator carried by the housing and comprising
 an actuator housing having opposing ends and opposing sides extending therebetween; 
 at least one coil carried by the actuator housing; 
 a field member having opposing ends and opposing sides extending therebetween, 
 a respective flexure coupling each end of the field member to an adjacent end of the actuator housing so that the field member is reciprocally movable within the actuator housing responsive to the at least one coil over an operating range and while maintaining a respective sidewall clearance between each side of the field member and an adjacent side of the housing, and 
 at least one sidewall clearance restricting feature configured to restrict the sidewall clearance when the field member moves beyond the operating range when subject to mechanical shock; and 
 
 a controller coupled to the wireless communications circuitry and the haptic actuator and configured to perform at least one wireless communications function and selectively operate the haptic actuator, respectively. 
 
     
     
       13. The electronic device of  claim 12  wherein the at least one sidewall clearance restricting feature comprises at least one protruding body carried by the actuator housing and extending within the respective sidewall clearance. 
     
     
       14. The electronic device of  claim 13  wherein the field member has a recess therein adjacent the at least one protruding body. 
     
     
       15. The electronic device of  claim 13  wherein the actuator housing comprises metal; and wherein the at least one protruding body comprises an at least one stamped metal protruding body. 
     
     
       16. The electronic device of  claim 12  wherein the at least one sidewall clearance restricting feature comprises at least one protruding body carried by the field member and extending within the respective sidewall clearance. 
     
     
       17. The electronic device of  claim 16  wherein the actuator housing has a recess therein adjacent the at least one protruding body. 
     
     
       18. A method of making a haptic actuator comprising a housing having opposing ends and opposing sides extending therebetween, at least one coil carried by the housing, and a field member having opposing ends and opposing sides extending therebetween, the method comprising:
 positioning a respective flexure coupling each end of the field member and an adjacent end of the housing so that the field member is reciprocally movable within the housing responsive to the at least one coil over an operating range and while maintaining a respective sidewall clearance between each side of the field member and an adjacent side of the housing; and 
 forming at least one sidewall clearance restricting feature to restrict the sidewall clearance when the field member moves beyond the operating range when subject to mechanical shock. 
 
     
     
       19. The method of  claim 18  wherein forming the at least one sidewall clearance restricting feature comprises forming at least one protruding body carried by the housing and extending within the respective sidewall clearance. 
     
     
       20. The method of  claim 19  further comprising forming a recess in the field member adjacent the at least one protruding body. 
     
     
       21. The method of  claim 19  wherein the housing comprises metal; and wherein forming the at least one protruding body comprises forming at least one stamped metal protruding body. 
     
     
       22. The method of  claim 18  wherein forming the at least one sidewall clearance restricting feature comprises forming at least one protruding body carried by the field member and extending within the respective sidewall clearance. 
     
     
       23. The method of  claim 22  further comprising forming a recess in the housing adjacent the at least one protruding body.

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 having opposing ends and opposing sides extending therebetween. The haptic actuator may also include at least one coil carried by the housing and a field member having opposing ends and opposing sides extending therebetween. The haptic actuator may also include a respective flexure coupling each end of the field member to an adjacent end of the housing so that the field member is reciprocally movable within the housing responsive to the at least one coil over an operating range and while maintaining a respective sidewall clearance between each side of the field member and an adjacent side of the housing. At least one sidewall clearance restricting feature may be configured to restrict the sidewall clearance when the field member moves beyond the operating range when subject to mechanical shock. 
     The at least one sidewall clearance restricting feature may include at least one protruding body carried by the housing and extending within the respective sidewall clearance. The field member may have a recess therein adjacent the at least one protruding body, for example. 
     The housing may include metal, for example. The at least one protruding body may include an at least one stamped metal protruding body. 
     The at least one sidewall clearance restricting feature may include at least one protruding body carried by the field member and extending within the respective sidewall clearance, for example. The housing may have a recess therein adjacent the at least one protruding body. 
     Each respective flexure may have a wishbone shape and include two diverging arms joined together at proximal ends and having spaced distal ends operatively coupled between adjacent ends of the field member and the housing, for example. Each respective flexure may have a bend therein joining together the two diverging arms at the proximal ends. 
     The haptic actuator may include a respective at least one anchor member coupled to an adjacent end of the housing and spaced from an adjacent end of the field member, for example. Each respective flexure may be coupled between the respective at least one anchor member and the field member, for example. The field member may include at least one permanent magnet adjacent the at least one coil. 
     A method aspect is directed to a method of making a haptic actuator that includes a housing having opposing ends and opposing sides extending therebetween, at least one coil carried by the housing, and a field member having opposing ends and opposing sides extending therebetween. The method may include positioning a respective flexure coupling each end of the field member and an adjacent end of the housing so that the field member is reciprocally movable within the housing responsive to the at least one coil over an operating range and while maintaining a respective sidewall clearance between each side of the field member and an adjacent side of the housing. The method may also include forming at least one sidewall clearance restricting feature to restrict the sidewall clearance when the field member moves beyond the operating range when subject to mechanical shock. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic diagram of an electronic device in accordance with an embodiment. 
         FIG. 2  is another schematic diagram of the electronic device of  FIG. 1 . 
         FIG. 3  is a schematic diagram of a portion of the haptic actuator of  FIG. 2 . 
         FIG. 4  is a schematic diagram of a prior art portion of the haptic actuator of  FIG. 2 . 
         FIG. 5  is a schematic diagram of the prior art haptic actuator of  FIG. 4  illustrating rotating and shifting of the field member from mechanical stress. 
         FIG. 6  is a schematic diagram of a flexure in accordance with the prior art. 
         FIG. 7  is a more detailed schematic diagram of a portion of the haptic actuator of  FIG. 2 . 
         FIG. 8  is a schematic diagram of a portion of a haptic actuator in accordance with another embodiment. 
         FIG. 9  is a schematic cross-sectional view of a portion of the haptic actuator of  FIG. 8  taken along line  8 - 1 . 
     
    
    
     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 is used to indicate similar elements in alternative embodiments. 
     Referring initially to  FIGS. 1-3 , 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 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. 4-5 , the haptic actuator  40  includes an actuator housing  41  that may be metal, for example. The actuator housing  41  may be another type of material or include more than one type of material. The actuator housing  41  has opposing ends  42   a ,  42   b  and opposing sides  43   a ,  43   b . The actuator housing  41  illustratively has a dimension in a length direction greater than a width direction (e.g., x-axis travel direction). The haptic actuator  40  also includes first and second coils  44 ,  45  carried by the actuator housing  41 , for example, the top and the bottom, respectively. The first and second coils  44 ,  45  may each have a loop shape or “racetrack” shape and are aligned in a stacked relation and spaced apart. There may be any number of first and second coils  44 ,  45  as will be appreciated by those skilled in the art. 
     The haptic actuator  40  also includes a field member  50  carried by the actuator housing  41 . The field member  50 , similarly to the actuator housing  41 , has opposing ends  53   a ,  53   b  and opposing sides  54   a ,  54   b  extending therebetween. The field member  50 , similarly to the actuator 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 permanent magnets  51  between the first and second coils  44 ,  45 . The permanent magnets  51  may be neodymium, for example, and may be positioned in opposing directions with respect to their respective poles. 
     The permanent magnets  51  may also have a rounded rectangle shape and may be aligned along a length of the first and second coils  44 ,  45 . There may be any number of permanent magnets  51  having any shape between the first and second coils  44 ,  45 . 
     The field member  50  also includes masses  57   a ,  57   b  adjacent the permanent magnets  51 . The masses  57   a ,  57   b  may be tungsten, for example. The masses  57   a ,  57   b  may be a different material (e.g., relatively heavy material) and there may be any number of masses. In some embodiments, the field member  50  or a portion thereof may be tungsten (or other heavy material) and/or define the masses (e.g., instead of discrete masses). 
     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 actuator housing  41  responsive to the first and second coils  44 ,  45  over an operating range. Each respective flexure  60  also couples the field member  50  so that during operation, the field member reciprocally moves within the actuator housing  41  over the operating range while maintaining a respective sidewall clearance  58  between each side  54   a ,  54   b  of the field member and an adjacent side  43   a ,  43   b  of the actuator housing. 
     Referring now additionally to  FIG. 6 , each flexure  60  illustratively has a wishbone or Y-shape, with two diverging arms  62   a ,  62   b  joined together at proximal ends  75   a ,  75   b . The two diverging arms  62   a ,  62   b  have spaced distal ends  76   a ,  76   b  operatively coupled between adjacent portions of the field member  50  and the actuator housing  41 . 
     A bend  78  joins together the two diverging arms  62   a ,  62   b  at the proximal ends  75   a ,  75   b . The bend  78  causes the two diverging arms  62   a ,  62   b  to be spaced apart at the distal ends  76   a ,  76   b . Illustratively, the two diverging arms  62   a ,  62   b  include a parallel portion  77   a ,  77   b  at the distal ends  76   a ,  76   b . In some embodiments, the distal ends  76   a ,  76   b  of the two diverging arms  62   a ,  62   b  may continue to diverge instead of turning or becoming parallel. While an example flexure  60  is illustrated, each flexure may have a different shape and more than one flexure may be used to couple each end  53   a ,  53   b  of the filed member  50  to an adjacent end  42   a ,  42   b  of the actuator housing  41 . 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. 
     Flexure bodies  66   a ,  66   b  are carried facing one another by the parallel portions  77   a ,  77   b  at or between the distal ends  76   a ,  76   b  ( FIGS. 4-5 ). Mechanical stops  72   a ,  72   b  are adjacent the proximal ends  75   a ,  75   b  ( FIGS. 4-5 ). More particularly, first and second mechanical stops  72   a ,  72   b  are between the proximal ends  75   a ,  75   b  and the adjacent sides  43   a ,  43   b ,  54   a ,  54   b  of the actuator housing  41  and the field member  50 , respectively. The first and second mechanical stops  72   a ,  72   b  may be an elastomeric material, for example. A third mechanical stop  73  is carried by the distal end  76   a  of one of the diverging arms  62   a , and more particularly, is between the distal ends  76   a ,  76   b  and carried by the flexure body  66   b  ( FIGS. 4-5 ). The third mechanical stop  73  may be a material similar to the first and second mechanical stops  72   a ,  72   b . The third mechanical stop  73  may be carried by the other diverging arm  62   b.    
     A respective anchor member  79  is coupled between each flexure  60  and the adjacent end  42   a ,  42   b  of the actuator housing  41  ( FIGS. 4-5 ). More particularly, the anchor member  79  is coupled between a distal end  76   a  of an arm  62   a  and the side  42   a  of the housing  41 . 
     As will be appreciated by those skilled in the art, the haptic actuator  40  is designed to operate within a given operating range and within a given set of operating specifications, for example, range of motion, sound level, etc. However, when the haptic actuator  40  is subject to mechanical shock, for example, during a drop, each flexure  60  may become plastically deformed causing the haptic actuator to no longer satisfy desired characteristics. More particularly, the plastic deformation may cause a permanent offset of the field member  50 . Permanent offset of the field member  50  may cause increased power draw for an idle mode, for example, by holding the zero position, and in an active mode, for example, by using more power to operate the haptic actuator  40 . Additionally, a relatively large offset can lead to “phantom clicks” unless parking algorithms are used and enough latency is allowed. Repeated plastic deformation may also negatively impact flexure and module life time reliability. 
     More particularly, a flexure  60  is designed to deform in the x-axis direction ( FIG. 4 ). Deformation y-axis and z-axis direction may lead to relatively large stresses. Gaps in the y-axis and z-axis directions may be reduced through actuator tolerances—without causing contact during operation. However, off-center contact (e.g., of the mechanical stop  72   a ,  72   b ) generally results in the field member  50  rotating and deforming flexures in the y-axis direction ( FIG. 5 ). The resistance of a flexure to y-axis deformation may be higher in the closed-position leading to high stresses and plastic deformation ( FIG. 5 ). Off-center stopping force results in the field member  50  rotating and shifting down in y-axis direction ( FIG. 5 ). 
     Thus, it may be desirable to lower plastic deformation, and thus battery usage and module reliability, for example, after being subjected to mechanical shock. To address this, the field member-to-actuator housing gap (i.e., the sidewall clearance) for the x-axis direction of travel is closed beyond operational travel range. In this way, stresses may be reduced or limited during a drop or mechanical shock and while not causing unwanted contact during normal operation. 
     Referring additionally to  FIG. 7 , the haptic actuator  40  includes a sidewall clearance restricting feature in the form of a protruding body  90  carried by a side  43   b  of the actuator housing  41  and extending within the respective sidewall clearance  58 . The protruding body  90  restricts the sidewall clearance  58  when the field member  50  moves beyond the operating range when subject to mechanical shock. Mechanical shock may include drops, impacts, and relatively high accelerations (e.g., beyond a threshold) with or without impact. There may be more than one protruding body  90  along the same side  43   b  of the actuator housing  41  and/or there may one or more protruding bodies carried by another side  43   a  of the actuator housing. Where the actuator housing  41 , and more particularly, the side  43   b  includes metal, the protruding body  90  may be in the form of a stamped metal protruding body. The protruding body  90  may be the same material as the actuator housing  41  or may be another material, for example, epoxy. 
     The field member  50  also illustratively includes a recess  91  therein adjacent the protruding body  90 . The recess  91  cooperates with the protruding body  90  to permit the protruding body  90  to be positioned closer to the field member  50  and away from the bend  78  of the flexure  60 . The protruding body  90  may be integrally formed with the actuator housing  41  or formed separately and coupled to the actuator housing. The recess  91  may span the full height of the field member  50  (i.e., a complete cutaway of a portion of the field member). The recess  91  may also be less than the height of the field member  50 , for example, and sized to be larger than the height of the protruding body  90  carried by the actuator housing  41  (such as, for example, a slot within the field member sized to include any tolerances in the size and position of the protruding body). 
     The protruding body  90  and the recess  91  reduce the y-axis gap or sidewall clearance beyond operational travel resulting in a variable gap or sidewall clearance  58 . A simulated drop or mechanical shock for a haptic actuator  40  with the protruding body  90  predicts 68 μm of permanent offset as opposed to 150 μm without the protruding body. 
     Referring now to  FIGS. 8-9 , in another embodiment, protruding bodies  90   a ′,  90   b ′ may be carried by the respective sides  54   a ′,  54   b ′, of the field member  50 ′. Corresponding recesses  91   a ′,  91   b ′ are illustratively formed in the corresponding sides  43   a ′,  43   b ′ of the actuator housing  41 ′. Similar to the embodiments, described above, the field member  50 ′ is reciprocally movable within the actuator housing  41 ′ over an operating range and while maintaining a respective sidewall clearance  58   a ′,  58   b ′ between each side  54   a ′,  54   b ′ of the field member and an adjacent side  43   a ′,  43   b ′ of the actuator housing. The protruding bodies  90   a ′,  90   b ′ restrict the sidewall clearance  58   a ′,  58   b ′ when the field member  50 ′ moves beyond the operating range when subject to mechanical shock. While two protruding bodies  90   a ′,  90   b ′ and corresponding recesses  91   a ′,  91   b ′ are illustrated, it should be appreciated by those skilled in the art that there may be more than two protruding bodies and recesses or a single protruding body and recess. Elements illustrated but not specifically described herein with respect to the present embodiment are similar to those described above and need no further description herein. 
     In any of the embodiments described herein, more than one protruding body  90  may be used along either or both the same side or different sides of the actuator housing  41 . For example, there may be a protruding body  90  (and corresponding recess  91 ) on each adjacent corner or two on each side  43   a ,  43   b  of actuator housing  41  adjacent respective opposing ends  42   a ,  42   b . Moreover, a protruding body  90  and recess  91  may be similarly used to restrict the clearance in the z-axis direction. 
     A method aspect is directed to a method of making a haptic actuator  40  that includes an actuator housing  41  having opposing ends  42   a ,  42   b  and opposing sides  43   a ,  43   b  extending therebetween, at least one coil  44 ,  45  carried by the actuator housing, and a field member  50  having opposing ends  53   a ,  53   b  and opposing sides  54   a ,  54   b  extending therebetween. The method includes positioning a respective flexure  60  coupling each end  53   a ,  53   b  of the field member  50  and an adjacent end  42   a ,  42   b  of the actuator housing  41  so that the field member  50  is reciprocally movable within the actuator housing responsive to the at least one coil  44 ,  45  over an operating range and while maintaining a respective sidewall clearance  58  between each side of the field member and an adjacent side of the actuator housing. The method also includes forming at least one sidewall clearance restricting feature  90  to restrict the sidewall clearance  58  when the field member  50  moves beyond the operating range when subject to mechanical shock. 
     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: 20180427
Publication Date: 20190507
Grant Date: 20190507
Priority Date: 20180427
Inventors: AMIN-SHAHIDI, DARYA
ABRAHAMSON, SCOTT D.
TOWASHIRAPORN, PONGPINIT
Assignee: APPLE INC
CPC Classifications: [{"code": "G06F3/016", "inventive": true, "first": true, "tree": "[]"}, {"code": "G06F3/016", "inventive": true, "first": true, "tree": "[]"}, {"code": "G06F1/1643", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F1/1684", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/016", "inventive": true, "first": true, "tree": "[]"}]
Family ID: 66333968