PATENT DOCUMENT

Publication Number: US-10671166-B2
Application Number: US-201715659235-A
Country: US
Kind Code: B2

Title: Electronic device including Halbach array based haptic actuator and related methods

Abstract:
An electronic device may include a haptic actuator. The haptic actuator may include a haptic actuator housing, at least coil carried by the haptic actuator housing, and a Halbach array of permanent magnets movable within the haptic actuator housing responsive to the at least one coil. The electronic device may also include a controller coupled to the at least one coil.

Claims:
That which is claimed is: 
     
       1. An electronic device comprising:
 a haptic actuator comprising
 a haptic actuator housing, 
 at least one upper coil carried by the haptic actuator housing, 
 at least one lower coil carried by the haptic actuator housing in offset relation to the at least one upper coil, and 
 a Halbach array of permanent magnets movable within the haptic actuator housing responsive to the at least one upper and lower coils, the Halbach array of permanent magnets having a first side adjacent the at least one upper and lower coils; and 
 
 a controller coupled to the at least one coil. 
 
     
     
       2. The electronic device of  claim 1  wherein the haptic actuator comprises at least one flexure member coupling the Halbach array of permanent magnets to the actuator housing so that the Halbach array of permanent magnets is movable along an x-axis and in a z-axis direction within the haptic actuator housing responsive to the at least one coil. 
     
     
       3. The electronic device of  claim 2  wherein the controller is configured to selectively drive the at least one coil so that the Halbach array of permanent magnets is movable in at least one of x-axis and z-axis directions. 
     
     
       4. The electronic device of  claim 1  wherein the haptic actuator housing has first and second ends, and wherein the haptic actuator comprises first and second flexure members between the first and second actuator housing ends and adjacent portions of the Halbach array of permanent magnets. 
     
     
       5. The electronic device of  claim 1  wherein the controller is configured to determine at least one of voltage and current, and drive the at least one coil based upon the at least one of voltage and current. 
     
     
       6. The electronic device of  claim 1  wherein the haptic actuator further comprises a magnetic sensor carried by the haptic actuator housing and coupled to the controller. 
     
     
       7. The electronic device of  claim 1  further comprising a ferritic shield adjacent the Halbach array of permanent magnets. 
     
     
       8. A haptic actuator comprising:
 a haptic actuator housing; 
 at least one coil carried by the haptic actuator housing; 
 a Halbach array of permanent magnets movable within the haptic actuator housing responsive to the at least one coil; and 
 at least one flexure member coupling the Halbach array of permanent magnets to the haptic actuator housing so that the Halbach array of permanent magnets is movable along an x-axis and in a z-axis direction within the haptic actuator housing responsive to the at least one coil. 
 
     
     
       9. The haptic actuator of  claim 8  wherein the at least one coil is adjacent a first side of the Halbach array of permanent magnets and comprises at least one upper coil and at least one lower coil carried below the at least one upper coil. 
     
     
       10. The haptic actuator of  claim 9  wherein the at least one upper coil is carried in offset relation to the at least one lower coil. 
     
     
       11. The haptic actuator of  claim 8  wherein the haptic actuator housing has first and second ends, and further comprising first and second flexure members between the first and second actuator housing ends and adjacent portions of the Halbach array of permanent magnets. 
     
     
       12. The haptic actuator of  claim 8  further comprising a magnetic sensor carried by the haptic actuator housing. 
     
     
       13. A method of making a haptic actuator comprising:
 positioning at least one upper coil carried by a haptic actuator housing; 
 positioning at least one lower coil carried by the haptic actuator housing and in offset relation to the at least one upper coil; and 
 positioning a Halbach array of permanent magnets movable within the haptic actuator housing to be responsive to the at least one upper and lower coils, the Halbach array of permanent magnets having a first side adjacent the at least one upper and lower coils. 
 
     
     
       14. The method of  claim 13  further comprising coupling, using at least one flexure member, the Halbach array of permanent magnets to the actuator housing so that the Halbach array of permanent magnets is movable along an x-axis and in a z-axis direction within the haptic actuator housing responsive to the at least one coil. 
     
     
       15. The method of  claim 13  wherein the haptic actuator housing has first and second ends, and further comprising positioning first and second flexure members between the first and second actuator housing ends and adjacent portions of the Halbach array of permanent magnets.

Description:
RELATED APPLICATIONS 
     The present application claims the priority benefit of provisional application Ser. No. 62/380,106 filed on Aug. 26, 2016, the entire contents of which are herein incorporated in its 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 haptic actuator. The haptic actuator may include a haptic actuator housing, at least one coil carried by the haptic actuator housing, and a Halbach array of permanent magnets movable within the haptic actuator housing responsive to the at least one coil. The electronic device may also include a controller coupled to the at least one coil. 
     The at least one coil may be adjacent a first side of the Halbach array of permanent magnets and may include at least one upper coil and at least one lower coil carried below the at least one upper coil. The at least one upper coil may be carried in offset relation to the at least one lower coil, for example. The at least one coil comprise a first coil and a second coil interleaved with the first coil. 
     The haptic actuator may include at least one flexure member coupling the Halbach array of permanent magnets to the actuator housing so that the Halbach array of permanent magnets is movable along an x-axis and in a z-axis direction within the haptic actuator housing responsive to the at least one coil. The controller may be configured to selectively drive the at least one coil so that the Halbach array of permanent magnets is movable in at least one of x-axis and z-axis directions, for example. 
     The haptic actuator housing may have first and second ends, and the haptic actuator may include first and second flexure members between the first and second actuator housing ends and adjacent portions of the Halbach array of permanent magnets, for example. 
     The controller may be configured to determine at least one of voltage and current, and drive the at least one coil based upon the at least one of voltage and current. The haptic actuator further includes a magnetic sensor carried by the haptic actuator housing and coupled to the controller, for example. The electronic device may further include a ferritic shield adjacent the Halbach array of permanent magnets. 
     A method aspect is directed to a method of making a haptic actuator. The method may include positioning at least one coil carried by a haptic actuator housing and positioning a Halbach array of permanent magnets movable within the haptic actuator housing to be responsive to the at least one coil. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of an electronic device including a haptic actuator according to an embodiment of the present invention. 
         FIG. 2  is a schematic block diagram of the electronic device of  FIG. 1 . 
         FIG. 3  is a detailed cut-away perspective view of the haptic actuator of  FIG. 1 . 
         FIG. 4  is a detailed partial exploded view of the haptic actuator of  FIG. 3 . 
         FIG. 5  is a detailed perspective view of the haptic actuator of  FIG. 3 . 
         FIG. 6  is a perspective view of interleaved coils of a haptic actuator in accordance with an embodiment. 
         FIG. 7  is a schematic diagram illustrating field directions for creating the haptic feedback in both the x-axis and z-axis directions for a haptic actuator in accordance with an embodiment. 
         FIG. 8 a    is a graph illustrating the induced magnetic field in the upper and lower coils that generates movement in the z-axis direction in accordance with an embodiment. 
         FIG. 8 b    is a graph illustrating the induced magnetic field in the upper and lower coils that generates movement in the x-axis direction in accordance with an embodiment. 
         FIGS. 9 a  and 9 b    are graphs illustrating the Lorentz force generated by the lower and upper coils, respectively, by a haptic actuator in accordance with an 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. 
     Referring initially to  FIGS. 1 and 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 mobile telephone. The electronic device  20  may be another type of electronic device, for example, a wearable wireless communications device, and includes a band or strap for securing it to a user, 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 a light emitting diode (LED) display, for example, or may be another type of display, for example, a liquid crystal display (LCD) as will be appreciated by those skilled in the art. The display  23  may be a touch display, for example, responsive to user input. 
     A finger-operated user input device  24  illustratively in the form of a pushbutton switch is also carried by the device housing  21  and is coupled to the controller  22 . The pushbutton switch  24  cooperates 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. In some embodiments, there may not be a discrete finger-operated user input device  24  and/or when the display  23  is in the form of a touch screen display, the display may be a finger-operated input device. 
     Referring now additionally to  FIGS. 3-5 , the electronic device  20  illustratively includes a haptic actuator  40 . The haptic actuator  40  is coupled to the controller  22 , which determines user indications and operates the haptic actuator by way of applying power, current, or a voltage to coils  44   a ,  44   b  to move a field member  50  based upon the user indication. More particularly, the haptic actuator  40  cooperates with the controller  22  to provide haptic feedback to the user. The haptic feedback may be in the form of relatively long and short vibrations or “taps”, particularly, for example, when the electronic device  20  is in the form of a wearable device and the user is wearing the electronic device. The vibrations may be indicative of a message received, and the duration 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, and some or all of die circuitry may be carried by an actuator housing and/or by the device housing  21 . 
     Further details of the haptic actuator  40  are now described. The haptic actuator  40  illustratively includes an actuator housing  41 . An upper coil  44   a  and a lower coil  44   b  are each carried by the actuator housing  41  in offset relation to one another. In other words, the upper coil  44   a  is laterally offset from the lower coil  44   b , for example, by a quarter pitch in offset. Of course, there may be more than two coils carried by the actuator housing  41 . In some embodiments, the upper and lower coils  44   a ,  44   b  may be mounted directly to the layers of the display  23 . 
     Referring briefly to  FIG. 6 , first, second, and third coils  44   a ′,  44   b ′,  44   c ′ are interleaved. Thus the first, second, and third coils  44   a ′,  44   b ′,  44   c ′ would be in the same z-axis plane, i.e., not offset in the z-axis direction. However, the first, second, and third coils  44   a ′,  44   b ′,  44   c ′ may each be laterally offset, i.e., in the x-axis direction, for example, by half a pitch. The interleaved coils may increase efficiency. 
     Referring again to  FIGS. 3-5 , the field member  50  is movable within the housing  41  responsive to the upper and lower coils  44   a ,  44   b . The movement of the field member  50 , for example, in the x-axis direction and the z-axis direction creates the haptic feedback, or tapping, which may be localized, as will be appreciated by those skilled in the art and described in further detail below. 
     The field member  50  may include one or more masses  51  and may be shaped for a particular application or operation. The field member  50  also includes a Halbach array of permanent magnets  52  adjacent a first side of the upper and lower coils  44   a ,  44   b . The Halbach array of permanent magnets  52  cooperates with the upper and lower coils  44   a ,  44   b  to provide movement of the field member  50  in either or both of the x-axis direction and the z-axis direction. 
     The haptic actuator  40  also includes biasing members  54   a ,  54   b  between respective first and second ends  55   a ,  55   b  of the actuator housing  41  and the field member  50 . The biasing members  54   a ,  54   b  are illustratively in the form of flexure members for maintaining the field member, and more particularly, adjacent portions of the Halbach array of permanent magnets  52  suspended in the actuator housing  41 . The flexure members  54   a ,  54   b  permit the field member including the Halbach array of permanent magnets  52  to be movable along the x-axis and z-axis directions within the haptic actuator housing  41  responsive to the upper and lower coils  44   a ,  44   b . In other embodiments, the flexure members  54   a ,  54   b  may be in other forms, such as, for example, mechanical springs. 
     Typically, circuitry, for example, the controller  22 , generates a sinusoidal drive waveform that drives the field member to move from an initial at-rest position, for example, in the x-axis direction. By way of cooperation between the Halbach array of permanent magnets  52  and the upper and lower coils  44   a ,  44   b , the controller may drive the field member via the coils, for example, independently, to move also in the z-axis direction. In other words, the field member  50  has two degrees of freedom to permit the dual-axis driving. More particularly, the controller  22  may drive the field member  50  to provide localized z-axis feedback in addition to the typically x-axis feedback. The controller  22  may drive the field member in the x-axis direction independently from the z-axis direction or simultaneously in the z-axis direction. The two degrees of freedom of the field member  50  may be have different resonant frequencies associated therewith and, accordingly, for example, different functions. For example, the one of the x-axis or z-axis feedback may be a low frequency, long duration waveform (e.g., an alert vibe) while the other of the x-axis and z-axis feedback may be a more localized crisp (e.g., short duration), high frequency waveform. 
     More particularly, the Halbach array of permanent magnets  52  produces a single-sided periodic magnetic field, as will be appreciated by those skilled in the art. The Halbach array of permanent magnets  52  induces a magnetic field in the x-axis direction in one of the upper and lower coils  44   a ,  44   b , and a magnetic field in the z-axis direction in the other of the upper and lower coils in nominal conditions, which results in a Lorentz force in the z-axis and x-axis directions, respectively. Therefore, the controller  22 , by controlling the electrical current into the upper and lower coils  44   a ,  44   b , can control both x-axis and z-axis forces. 
       FIG. 7  schematically illustrates field directions for creating the haptic feedback in both the x-axis and z-axis directions. With respect to the upper and lower coils  44   a ,  44   b , “X” indicates the current being directed into the plane of the drawing (i.e., into the page) and a “circled dot” illustrates the current being directed out of the plane of the drawing (i.e., away from the page). With respect to the Halbach array of permanent magnets  52 , the arrows indicate each magnet&#39;s magnetic field orientation. The graph  60  in  FIG. 8 a    illustrates the induced magnetic field in the upper and lower coils  44   a ,  44   b  at the x=0 position that would generate movement in the z-axis direction. The graph  61  in  FIG. 8 b    illustrates the induced magnetic field in the upper and lower coils  44   a ,  44   b  at the x=0 position that would generate movement in the x-axis direction. 
     The controller  22  may also generate position and velocity information regarding the field member  50 . The position and velocity information may be obtained by a magnetic sensor  49  carried by the haptic actuator housing  41  and coupled to the controller  22 . Position and velocity information may alternatively and/or additionally be obtained by an optical sensor, an acoustic sensor, and/or any other sensing device or technique for determining position and velocity information. The controller may also determine one or more of voltage and current, e.g. back electromotive force (BEMF), and drive the upper and lower coils  44   a ,  44   b , and the field member  50 , accordingly. The controller  22  may also drive the coils  44   a ,  44   b  or the field member  50  with dual frequencies (i.e. two-phase), for example, one to provide a softer x-axis feedback, and one to provide a stiffer z-axis feedback, as will be appreciated by those skilled in the art. Of course, other and/or additional waveforms having different characteristics may be used to drive the coils  44   a ,  44   b  and field member  50  with desired characteristics in either or both of the x-axis and z-axis directions. 
     Referring now to the graphs  63 ,  64  in  FIGS. 9 a  and 9 b   , the Lorentz force generated by the lower and upper coils  44   b ,  44   a  are illustratively shown. The graph  63  illustrates the Lorentz force in the lower coil  44   b  with respect to x-axis displacement. Forces in the x-axis direction  65  and y-axis  66  direction are illustrated. The graph  64  illustrates the Lorentz force generated in the upper coil  44   a  with respect to x-axis displacement. Forces in the x-axis direction  67  and y-axis  68  direction are illustrated. 
     The electronic device  20  also includes a ferritic shield  48  ( FIG. 7 ) that is adjacent the field member  50 , and more particularly, the Halbach array of permanent magnets  52 . The haptic actuator  40  may exhibit reduced magnetic leakage through the back of the system, for example, by controlling the magnetic fields by way of the Halbach array  52  and coils  44   a ,  44   b . There may also be reduced magnetic anti-spring compared to typical single axis haptic actuators. 
     The haptic actuator  40  may also include a cover  58  carried by the haptic actuator housing  41  adjacent a side of the upper and lower coils  44   a ,  44   b  that is opposite the Halbach array of permanent magnets  52 . The cover  58  may be secured to the haptic actuator housing  41  via a seal  59 , for example, a rubber gasket or other type of seal. In some embodiments, the cover  58  may be placed adjacent or below the display  23  of the electronic device  20  to provide haptic feedback through the display. For example, where the display  23  is a touch display, the haptic feedback may be localized, e.g., in the z-axis direction, at the location of the user input or touch. 
     In other embodiments, the haptic actuator  40  may include a Halbach array of permanent magnets  52  carried by the actuator housing  41 , and the field member  50  may include upper and lower coils  44   a ,  44   b  that cooperate with the Halbach array of permanent magnets. In other words, in contrast to the embodiments described above, the Halbach array of permanent magnets  52  may be stationary (i.e., carried by the actuator housing  41 ) and the upper and lower coils  44   a ,  44   b , as part of the field member  50  are moving (i.e., connected to the mass). Of course, there may be any number of coils and/or permanent magnets. 
     A method aspect is directed to a method of making a haptic actuator  40 . The method may include positioning at least one coil  44   a ,  44   b  carried by a haptic actuator housing  41  and positioning a Halbach array of permanent magnets  52  movable within the haptic actuator housing to be responsive to the at least one coil. 
     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: 20170725
Publication Date: 20200602
Grant Date: 20200602
Priority Date: 20160826
Inventors: HAJATI, ARMAN
Assignee: APPLE INC
CPC Classifications: [{"code": "H02K11/22", "inventive": false, "first": false, "tree": "[]"}, {"code": "H02K33/16", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F1/1684", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04M19/047", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F1/1626", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F1/1637", "inventive": true, "first": false, "tree": "[]"}, {"code": "H02K33/02", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/016", "inventive": true, "first": true, "tree": "[]"}, {"code": "H02K11/215", "inventive": false, "first": false, "tree": "[]"}, {"code": "H02K11/22", "inventive": false, "first": false, "tree": "[]"}, {"code": "H02K11/215", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F1/1684", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F1/1637", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F1/1626", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04M19/047", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F1/1684", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F1/1626", "inventive": true, "first": false, "tree": "[]"}, {"code": "H02K11/22", "inventive": false, "first": false, "tree": "[]"}, {"code": "H02K33/02", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04M19/047", "inventive": true, "first": false, "tree": "[]"}, {"code": "H02K11/215", "inventive": false, "first": false, "tree": "[]"}, {"code": "H02K33/16", "inventive": true, "first": false, "tree": "[]"}, {"code": "H02K33/02", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F1/1637", "inventive": true, "first": false, "tree": "[]"}, {"code": "H02K33/16", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/016", "inventive": true, "first": true, "tree": "[]"}, {"code": "G06F3/016", "inventive": true, "first": true, "tree": "[]"}]
Family ID: 61242490