PATENT DOCUMENT

Publication Number: US-8638320-B2
Application Number: US-201113166743-A
Country: US
Kind Code: B2

Title: Stylus orientation detection

Abstract:
Stylus orientation detection is disclosed. In an example, the orientation of a stylus relative to a contacting surface, e.g., a touch panel, can be detected by detecting a capacitance at one or more locations on the stylus relative to the surface, and then using the capacitance(s) to determine the orientation of the stylus relative to the surface. In another example, the orientation of a stylus relative to a contacting surface, e.g., a touch panel, can be detected by first detecting the orientation of the stylus relative to a reference, detecting the orientation of the contacting surface relative to the reference, and then calculating the orientation of the stylus relative to the contacting surface using the two detected orientations.

Claims:
What is claimed is: 
     
       1. A method for detecting an orientation of an input device, comprising:
 detecting a first capacitance, generated by a first electrode at a first location on the input device; 
 detecting a second capacitance, generated by a second electrode at a second location on the input device; 
 correlating the first and second capacitances; and 
 calculating the orientation of the input device based on the correlation. 
 
     
     
       2. The method of  claim 1 , wherein detecting the first capacitance comprises:
 capturing an image of the first capacitance on a touch sensitive surface; and 
 determining a location of the image of the first capacitance. 
 
     
     
       3. The method of  claim 1 , wherein detecting the second capacitance comprises:
 capturing an image of the second capacitance on a touch sensitive surface; and 
 determining a location of the image of the second capacitance. 
 
     
     
       4. The method of  claim 1 , wherein correlating the first and second capacitances comprises:
 determining proximity of the detected first and second capacitances relative to each other in an image; and 
 determining relative position of the detected first and second capacitances in the image. 
 
     
     
       5. The method of  claim 1 , wherein calculating the orientation of the input device comprises:
 determining the orientation based on at least one of a proximity or relative position of locations captured in an image of the detected first and second capacitances on a touch sensitive surface, wherein the closer the proximity the closer the orientation to being perpendicular with respect to the touch sensitive surface. 
 
     
     
       6. The method of  claim 1 , comprising:
 determining whether the input device has rotated based on the detected second capacitance. 
 
     
     
       7. The method of  claim 6 , wherein determining whether the device has rotated comprises:
 determining which portion of the input device forms the second capacitance; and 
 determining the rotation according to the determined portion. 
 
     
     
       8. A capacitive input device comprising:
 a first electrode at a tip of the input device; and 
 a second electrode proximate to the first electrode, wherein the first electrode is configured to form a first capacitance and the second electrode is configured to form a second capacitance, the first and second capacitances for detecting an orientation of the input device. 
 
     
     
       9. The device of  claim 8 , wherein the second electrode forms a ring around the input device at a distance from the tip. 
     
     
       10. The device of  claim 8 , wherein the second electrode comprises multiple segments. 
     
     
       11. The device of  claim 10 , wherein the segments form a broken ring around the input device at a distance from the tip. 
     
     
       12. The device of  claim 10 , wherein the segments are aligned in parallel around the input device at a distance from the tip. 
     
     
       13. The device of  claim 8 , wherein the second electrode is at the tip of the input device, the tip is flat, and the first and second electrodes are adjacent to each other, a flat surface of each of the first and second electrodes forming the flat tip. 
     
     
       14. The device of  claim 8 , comprising:
 a drive circuit to output a drive voltage through the first electrode, the drive circuit comprising a clock to generate the drive voltage, a microcontroller to control the drive voltage, and at least one amplifier to adjust the drive voltage. 
 
     
     
       15. The device of  claim 8 , comprising:
 a sense circuit to sense a voltage at the first electrode, the sense circuit comprising a sense amplifier to adjust the sensed voltage, a clock to generate a demodulation signal, a phase shifter to shift the phase of the demodulation signal, and a set of mixers to receive the sensed voltage and either the demodulation signal or the phase-shifted demodulation signal to demodulate the sensed voltage. 
 
     
     
       16. A method for detecting an orientation of a first device relative to a second device, comprising:
 sensing with a first sensor in the first device an orientation of the first device relative to a reference; 
 sensing with a second sensor in the second device an orientation of the second device relative to the reference; and 
 calculating an orientation of the first device relative to the second device based on the sensed orientations of the first and second devices relative to the reference. 
 
     
     
       17. The method of  claim 16 , comprising:
 sensing with a third sensor in the first device the orientation of the first device relative to the reference; and 
 comparing the sensed orientations from the first and third sensors to confirm the orientation of the first device relative to the reference. 
 
     
     
       18. The method of  claim 16 , comprising:
 transmitting the sensed orientation of the first device to the second device. 
 
     
     
       19. The method of  claim 18 , wherein calculating the orientation of the first device relative to the second device comprises:
 upon receipt of the transmitted sensed orientation of the first device, the second device calculating the orientation of the first device relative to the second device. 
 
     
     
       20. A system comprising:
 a first device including a first sensor to detect an orientation of the first device relative to a reference and a transmitter to transmit the detected orientation of the first device; and 
 a second device including a second sensor to detect an orientation of the second device relative to the reference, a receiver to receive the detected orientation from the first device, and a processor to calculate an orientation of the first device relative to the second device based on the detected orientations of the first and second devices relative to the reference. 
 
     
     
       21. A capacitive input device comprising:
 an electrode at a tip of an input device, the electrode configured to form a capacitance having an image shape and size indicative of an orientation of the input device; and 
 a second electrode of the input device, the second electrode configured to form a second capacitance having an image shape and size indicative of the orientation of the input device, wherein the second electrode is located at different locating than the electrode at the tip of the input device. 
 
     
     
       22. The device of  claim 21 , wherein the electrode forms the entire tip. 
     
     
       23. A method for detecting an orientation of an input device, comprising:
 detecting a plurality of capacitances on the input device; 
 determining a shape and a size in an image of the detected capacitances; and 
 calculating the orientation of the input device based on the determination. 
 
     
     
       24. The method of  claim 23 , wherein calculating the orientation of the input device comprises:
 calculating the orientation based on whether the shape in the image is a triangle or a circle and based on the shape size, wherein the more circular the shape the closer the orientation to being perpendicular to a surface, and wherein the smaller the size the closer the orientation to being perpendicular to the surface. 
 
     
     
       25. The method of  claim 23 , wherein calculating the orientation of the input device comprises:
 calculating the orientation based a location of a base of a triangular image relative to an apex of the triangular image, wherein, if the base is to the right of the apex in the triangular image, the orientation is tilted to the right.

Description:
FIELD 
     This relates generally to touch sensing and more particularly, to providing a stylus for use with a touch sensitive device and detecting an orientation of the stylus relative to the device. 
     BACKGROUND 
     Many types of input devices are available for performing operations in a computing system, such as buttons or keys, mice, trackballs, touch sensor panels, joysticks, touch pads, touch screens, and the like. Touch sensitive devices, and touch screens, in particular, are becoming increasingly popular because of their ease and versatility of operation as well as their declining price. Touch sensitive devices can include a touch sensor panel, which can be a clear panel with a touch sensitive surface, and a display device such as a liquid crystal display (LCD) that can be positioned partially or fully behind the panel, or integrated with the panel, so that the touch sensitive surface can substantially cover the viewable area of the display device. Touch sensitive devices can generally allow a user to perform various functions by touching or hovering over the touch sensor panel using one or more fingers, a stylus or other object at a location often dictated by a user interface (UI) including virtual buttons, keys, bars, displays, and other elements, being displayed by the display device. In general, touch screens can recognize a touch event and the position of the touch event on the touch sensor panel or a hover event and the position of the hover event on the touch sensor panel, and the computing system can then interpret the touch or hover event in accordance with the display appearing at the time of the event, and thereafter can perform one or more operations based on the event. 
     When a stylus has been used as an input device, the stylus has traditionally provided simply a touch input without additional information that can be helpful to the touch sensitive device for detecting touch or hover events. 
     SUMMARY 
     This relates to detection of an orientation of a stylus relative to a surface. In an example, the orientation of a stylus relative to a contacting surface, e.g., a touch panel, can be detected by detecting a capacitance at one or more locations on the stylus relative to the surface, and then using the capacitance(s) to determine the orientation of the stylus relative to the surface. In another example, the orientation of a stylus relative to a contacting surface, e.g., a touch panel, can be detected by first detecting the orientation of the stylus relative to a reference, detecting the orientation of the contacting surface relative to the reference, and then calculating the orientation of the stylus relative to the contacting surface using the two detected orientations. Stylus orientation can advantageously be used to affect width and darkness of a resultant line displayed on the touch panel, thereby improving the realism of the stylus experience. The stylus can advantageously be used to improve touch and hover sensing and to preserve power savings in the contacting device. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  illustrates an exemplary stylus for use with a touch panel according to various embodiments. 
         FIGS. 2   a  and  2   b  illustrate a side view and a bottom view respectively of an exemplary stylus according to various embodiments. 
         FIG. 3  illustrates a cross-sectional view of an exemplary stylus according to various embodiments. 
         FIGS. 4   a  and  4   b  illustrates a perpendicular orientation and a tilted orientation respectively of an exemplary stylus according to various embodiments. 
         FIG. 5  illustrates an exemplary method for detecting an orientation of a stylus according to various embodiments. 
         FIGS. 6   a  and  6   b  illustrate a side view and a bottom view respectively of another exemplary stylus according to various embodiments. 
         FIGS. 7   a ,  7   b , and  7   c  illustrate a perpendicular orientation, a tilted orientation, and a rotated-tilted orientation respectively of an exemplary stylus according to various embodiments. 
         FIG. 8  illustrates another exemplary method for detecting an orientation of a stylus according to various embodiments. 
         FIG. 9  illustrates an exemplary stylus having an orientation sensor for use with a touch panel also having an orientation sensor according to various embodiments. 
         FIG. 10  illustrates another exemplary method for detecting an orientation of a stylus according to various embodiments. 
         FIG. 11  illustrates an exemplary stylus tip having strip electrodes according to various embodiments. 
         FIG. 12  illustrates an exemplary stylus tip having a wide ring electrode according to various embodiments. 
         FIG. 13  illustrates an exemplary flat stylus tip according to various embodiments. 
         FIGS. 14   a  and  14   b  illustrate a side view and a bottom view respectively of another exemplary stylus according to various embodiments. 
         FIGS. 15   a  and  15   b  illustrate a perpendicular orientation and a tilted orientation respectively of an exemplary stylus according to various embodiments. 
         FIG. 16  illustrates another exemplary method for detecting an orientation of a stylus according to various embodiments. 
         FIG. 17  illustrates exemplary drive circuitry for a stylus according to various embodiments. 
         FIG. 18  illustrates exemplary sense circuitry for a stylus according to various embodiments. 
         FIG. 19  illustrates an exemplary computing system for use with a stylus according to various embodiments. 
         FIG. 20  illustrates an exemplary mobile telephone for use with a stylus according to various embodiments. 
         FIG. 21  illustrates an exemplary digital media player for use with a stylus according to various embodiments. 
         FIG. 22  illustrates an exemplary personal computer for use with a stylus according to various embodiments. 
     
    
    
     DETAILED DESCRIPTION 
     In the following description of example embodiments, reference is made to the accompanying drawings in which it is shown by way of illustration specific embodiments that can be practiced. It is to be understood that other embodiments can be used and structural changes can be made without departing from the scope of the various embodiments. 
     This relates to detection of an orientation of a stylus relative to a surface. In some embodiments, the orientation of a stylus relative to a contacting surface, e.g., a touch panel, can be detected by detecting a capacitance at one or more locations on the stylus relative to the surface, and then using the capacitance(s) to determine the orientation of the stylus relative to the surface. In some embodiments, the orientation of a stylus relative to a contacting surface, e.g., a touch panel, can be detected by first detecting the orientation of the stylus relative to a reference, detecting the orientation of the contacting surface relative to the reference, and then calculating the orientation of the stylus relative to the contacting surface using the two detected orientations. Stylus orientation can advantageously be used to affect width and darkness of a resultant line displayed on the touch panel, thereby improving the realism of the stylus experience. The stylus can advantageously be used to improve touch and hover sensing and to preserve power savings in the contacting device. 
     Although some embodiments are described herein in terms of a stylus, it is to be understood that other input devices and/or pointing devices can be used according to various embodiments. 
     Although some embodiments are described herein in terms of a touch panel, it is to be understood that other touch sensitive devices capable of sensing an object touching or hovering over the devices can be used according to various embodiments. 
       FIG. 1  illustrates an exemplary stylus for use with a touch panel according to various embodiments. In the example of  FIG. 1 , touch panel  120  can include an array of pixels  106  formed at the crossing points of conductive rows  101  and columns  102 . Though  FIG. 1  depicts the conductive elements  101 ,  102  in rows and columns, other configurations of conductive elements are also possible according to various embodiments. 
     When stylus  110  touches or hovers over a surface of the touch panel  120 , the stylus can form a capacitance with one or more of the conductive rows  101  and/or columns  102  that can be detected by sensing circuitry (not shown). The stylus touch or hover can be represented in an image captured at the touch panel  120  and processed for input information regarding the stylus  110 . 
     In some embodiments, the stylus  110  can act as a driving element stimulated by a stimulation signal to capacitively couple with a proximate conductive row  101  or column  102  of the touch panel  120 , thereby forming a capacitive path for coupling charge from the stylus to that proximate row or column. The proximate row  101  or column  102  can output signals representative of the coupling charge to the sensing circuitry. 
     In some embodiments, the stylus  110  can act as a sensing element capacitively coupled with a proximate conductive row  101  or column  102  of the touch panel  120  that has been stimulated by a stimulation signal. The stylus  110  can then output signals representative of the coupling charge to the sensing circuitry. 
       FIG. 2   a  illustrates a side view of an exemplary stylus according to various embodiments. In the example of  FIG. 2   a , stylus  210  can include shaft  218  and tip  212 . The tip  212  can include electrode  214  at the distal end of the tip for contacting a surface and electrode  216  proximate to the distal end and forming a ring around the tip. The electrodes  214 ,  216  can be any suitable conductive material, such as metal, paint, ink, and the like. In some embodiments, the tip can be replaceable. The shaft  218  can similarly be any suitable conductive material or any suitable insulating material, depending on the requirements of the stylus  210 . The shaft  218  can house stylus circuitry, e.g., signal transmitting and receiving elements, signal processing elements, and the like, depending on the requirements of the stylus  210 . 
       FIG. 2   b  illustrates a bottom view of the exemplary stylus of  FIG. 2   a  according to various embodiments. In the example of  FIG. 2   b , stylus  210  can have a conical shaped tip  212  with electrode  214  at the distal end of the tip and electrode  216  proximate to the distal end and forming a ring around the tip. 
       FIG. 3  illustrates a cross-sectional view of the exemplary stylus of  FIGS. 2   a  and  2   b . In the example of  FIG. 3 , tip  212  of stylus  210  can have electrode  214  that forms a distal end of the tip, with the distal end portion exposed to contact a surface and another portion of the electrode extended within the tip. The tip  212  can also have electrode  216  that forms a ring around the tip, with a portion of the electrode exposed on the outer surface of the tip and another portion of the electrode extended within the tip. Insulator  315  can separate the electrodes  214 ,  216  and cover the extended portion of the ring electrode  216 . The electrodes  214 ,  216  can electrically couple to circuit board  380  or other stylus circuitry for transmitting and receiving signals through connections  378 , for example. 
     A stylus can have various orientations as it touches or hovers over a touch panel. In some embodiments, a particular action of the touch panel can be performed based on the stylus orientation. Accordingly, detecting the stylus orientation can be helpful in touch panel operation. 
       FIGS. 4   a  and  4   b  illustrate various orientations of the exemplary stylus of  FIGS. 2   a  and  2   b  as it touches a touch panel according to various embodiments. In the example of  FIG. 4   a , stylus  410  can have a perpendicular orientation as it touches touch panel  420 . As the stylus  410  touches the panel  420 , tip electrode  414  can form capacitance C 1  with a proximate conductive element, e.g., row(s) and/or column(s), (not shown) of the panel. Similarly, ring electrode  416  can form capacitance C 2  with a proximate conductive element, e.g., row(s) and/or column(s), of the panel  420 . Image  430  captured at the panel  420  can show touch or hover images resulting from the two capacitances C 1 , C 2 . Because the stylus  410  is perpendicular to the panel  420 , the image  430  can show the tip capacitance C 1  image surrounded by the ring capacitance C 2  image. 
     In the example of  FIG. 4   b , the stylus  410  can have a tilted orientation as it touches the panel  420 . As a result, the image  430  captured at the panel  420  can show a shift in the positions of the touch or hover images resulting from two capacitances C 1 , C 2  relative to each other. Here, the ring capacitance C 2  image has shifted to the right of the tip capacitance C 1  image. The amount of the shift can be a function of the amount of stylus tilt. For example, the greater the tilt, the further the ring capacitance C 2  image is from the tip capacitance C 1  image. Conversely, the lesser the tilt, the closer the ring capacitance C 2  image is and/or overlaps the tip capacitance C 1  image. Therefore, by determining the proximity of the two capacitances C 1 , C 2  images in the captured image, the amount of stylus tilt can be determined. 
     The image can also be used to determine the direction of the stylus tilt, e.g., upward, downward, right, left, and so on, relative to the touch panel  420 . For example, in the image  430  of  FIG. 4   b , the ring capacitance C 2  image is to the right of the tip capacitance C 1  image. This can indicate that the stylus  410  is tilted to the right. If the ring capacitance C 2  image is at the left of the tip capacitance C 1  image, this can indicate that the stylus  410  is tilted to the left. If the ring capacitance C 2  image is above the tip capacitance C 1  image, this can indicate that the stylus  410  is tilted upward. If the ring capacitance C 2  image is below the tip capacitance C 1  image, this can indicate that the stylus  410  is tilted downward. Other tilt directions, e.g., upper left, lower right, etc., can also be determined according to the relative positions of the capacitance C 1 , C 2  images. 
     By determining the proximity of the two capacitances C 1 , C 2  to each other and their relative positions in an image, the stylus orientation can be detected. 
       FIG. 5  illustrates an exemplary method for detecting an orientation of a stylus according to various embodiments. This method can be used with the stylus of  FIGS. 2   a  and  2   b , for example. In the example of  FIG. 5 , a first capacitance formed between a stylus first electrode and a contacting surface can be detected ( 510 ). Similarly, a second capacitance formed between a stylus second electrode and the contacting surface can be detected ( 520 ). In some embodiments, the first electrode can be a tip electrode and the second electrode can be a ring electrode. In some embodiments, the capacitance detection can include capturing an image that can show touch or hover images resulting from the capacitances at the touch panel and performing a suitable image processing method on the captured image to determine the locations of the capacitance images therein. 
     The detected capacitance images in the captured image can be correlated ( 530 ). In some embodiments, the correlation can include determining the proximity of the two capacitance images in order to determine the tilt of the stylus and determining the relative positions of the two capacitance images in order to determine the direction of the stylus tilt. 
     The stylus orientation can then be calculated based on the correlation ( 540 ). In some embodiments, the orientation calculation can include determining the tilt angle based on the amount of proximity between the two capacitance images in the captured image and determining the direction of the stylus tilt based on the relative positions of the two capacitance images in the captured image. In some embodiments, lookup tables can be used, where one table&#39;s entries include a tilt angle-proximity amount pairing and another table&#39;s entries includes a tilt direction-relative position pairing. The proximity amount and relative positions could be inputted to the lookup tables and the corresponding tilt angle and tilt direction outputted therefrom. In some embodiments, equations can be used, where one equation calculates tilt angle as a function of proximity amount and another equation calculates tilt direction as a function of relative position. Other orientation calculation methods are also possible according to various embodiments. 
       FIG. 6   a  illustrates a side view of another exemplary stylus according to various embodiments. In the example of  FIG. 6   a , stylus  610  can include shaft  618  and tip  612 . The tip  612  can include electrode  614  at the distal end of the tip for contacting a surface and segment electrodes  616 -A,  616 -B,  616 -C proximate to the distal end and forming a broken ring around the tip. The stylus  610  of  FIG. 6   a  is like the stylus  210  of  FIG. 2   a , except that the ring electrode  216  of  FIG. 2   a  is replaced with segment electrodes  616 -A,  616 -B,  616 -C of  FIG. 6   a.    
       FIG. 6   b  illustrates a bottom view of the exemplary stylus of  FIG. 6   a  according to various embodiments. In the example of  FIG. 6   b , stylus  610  can have a conical shaped tip  612  with electrode  614  at the distal end of the tip and segment electrodes  616 -A,  616 -B,  616 -C proximate to the distal end and forming a broken ring around the tip. Though  FIG. 6   b  depicts three segment electrodes, it is to be understood that other numbers of electrodes, e.g., two, four, five, and so on, can be used according to various embodiments. 
     In addition to determining stylus tilt angle and tilt direction, similar to the stylus of  FIGS. 2   a  and  2   b , stylus rotation can be determined for the stylus of  FIGS. 6   a  and  6   b , as will be described below. 
       FIGS. 7   a ,  7   b , and  7   c  illustrate various orientations of the exemplary stylus of  FIGS. 6   a  and  6   b  as it touches a touch panel according to various embodiments. In the example of  FIG. 7   a , stylus  710  can have a perpendicular orientation as it touches touch panel  720 . As the stylus  710  touches the panel  720 , tip electrode  714  can form capacitance C 1  with a proximate conductive element, e.g., row(s) and/or column(s), (not shown) of the panel. Similarly, segment electrodes  716 -A,  716 -B,  716 -C can form capacitances C 2 , C 3 , C 4 , respectively with a proximate conductive element, e.g., row(s) and/or column(s), of the panel  720 . Image  730  captured at the panel  720  can show touch or hover images resulting from the four capacitances C 1 , C 2 , C 3 , C 4 . Because the stylus  710  is perpendicular to the panel  720 , the image  730  can show the image resulting from the tip capacitance C 1  surrounded by the images resulting from the segment capacitances C 2 , C 3 , C 4 . 
     In the example of  FIG. 7   b , the stylus  710  can have a tilted orientation as it touches the panel  720 . As a result, the image  730  captured at the panel  720  can show a shift in the positions of the tip capacitances C 1  image and the segment capacitance image (in this case, segment capacitance C 2  image) of the electrode (in this case, electrode  716 -A) closest to the panel  720 . The other segment capacitance images can disappear from the image  730 , as illustrated here. Alternatively, the other segment capacitance images can have smaller images that also shift depending on how the stylus is tilted and rotated. By determining the proximity of the two capacitances C 1 , C 2  images in the captured image, the amount of stylus tilt can be determined. 
     The captured image  730  can also be used to determine the direction of the stylus tilt relative to the touch panel  720 . For example, in the image  730  of  FIG. 7   b , the segment capacitance C 2  image is to the right of the tip capacitance C 1  image. This can indicate that the stylus  710  is tilted to the right. If the segment capacitance C 2  image is at the left of the tip capacitance C 1  image, this can indicate that the stylus  710  is tilted to the left. Other tilt directions, e.g., upward, downward, upper left, lower right, etc., can also be determined according to the relative positions of the capacitance C 1 , C 2  images (and any of the other segment capacitance images, if they are also shown in the captured image). 
     In the example of  FIG. 7   c , the stylus  710  can have a rotated-tilted orientation as it touches the panel  720 . As a result, the image  730  captured at the panel  720  can show another segment capacitance image (in this case, segment capacitance C 4  image) of another electrode (in this case, electrode  716 -C) closest to the panel  720 . The image  730  can be used to determine the amount of stylus tilt and tilt direction in the same manner as in  FIG. 7   b.    
     To determine the amount of stylus rotation, the strengths of the capacitances C 2 , C 3 , C 4  at the segment electrodes  716 -A,  716 -B,  716 -C, respectively, can be used. The closer an electrode is to the panel  720 , the stronger the capacitive coupling between the electrode and the panel, hence the stronger the capacitance. By estimating the strength of the capacitances relative to each other, the segment electrode closest to the panel can be determined. In some embodiments, the relative strength of the capacitances C 2 , C 3 , C 4  can be estimated based on the magnitudes of their corresponding images in the captured image. For example, in  FIG. 7   b , the segment electrode  716 -A would form the strongest of the capacitances and the other segment electrodes  716 -B,  716 -C would form weaker capacitances. In  FIG. 7   c , the segment electrode  716 -C would form the strongest of the capacitances and the other electrodes  716 -A,  716 -B would form weaker capacitances. Accordingly, by measuring the decrease in the magnitude of the capacitance C 2  image of electrode  716 -A and the increase in the magnitude of the capacitance C 4  image of electrode  716 -C over the time period indicated by  FIGS. 7   b  and  7   c , a determination can be made regarding how much the stylus  710  rotated between the orientations illustrated in  FIGS. 7   b  and  7   c.    
     Additionally, by determining the relative positions of the magnitude changes, the stylus rotation can be determined. For example, as the stylus rotates clockwise, the capacitance C 2 , C 4  images correspondingly rotate clockwise as their magnitudes change. Accordingly, a determination can be made regarding how much the stylus  710  rotated between the orientations illustrated in  FIGS. 7   b  and  7   c.    
     By determining the proximity of the capacitance C 1 , C 2 , C 3 , C 4  images to each other and their relative positions in the captured image and by determining the relative strengths of the segment capacitance C 2 , C 3 , C 4  images and/or their relative position changes in the captured image, the stylus orientation can be detected. 
       FIG. 8  illustrates another exemplary method for detecting an orientation of a stylus according to various embodiments. This method can be used with the stylus of  FIGS. 6   a  and  6   b , for example. In the example of  FIG. 8 , a first capacitance formed between a stylus first electrode and a contacting surface can be detected ( 810 ). Similarly, one or more second capacitances formed between one or more stylus second electrodes and the contacting surface can be detected ( 820 ). In some embodiments, the first electrode can be a tip electrode and the second electrode(s) can be segment electrode(s). In some embodiments, the capacitance detection can include capturing an image that can show touch or hover images resulting from the capacitances at the touch panel and performing a suitable image processing method on the captured image to determine the locations of the capacitance images in the captured image. 
     The detected capacitance images in the captured image can be correlated ( 830 ). In some embodiments, the correlation can include determining the proximity of the capacitance images in the captured image in order to determine the tilt of the stylus and determining the relative positions of the capacitance images in the captured image in order to determine the direction of the stylus tilt. 
     The stylus tilt angle and tilt direction can then be calculated based on the correlation ( 840 ). In some embodiments, the calculation can include determining the tilt angle based on the amount of proximity between the capacitance images in the captured image and determining the direction of the stylus tilt based on the relative positions of the capacitance images in the captured image. In some embodiments, lookup tables can be used, where one table&#39;s entries include a tilt angle-proximity amount pairing and another table&#39;s entries includes a tilt direction-relative position pairing. The proximity amount and relative positions could be inputted to the lookup tables and the corresponding tilt angle and tilt direction outputted therefrom. In some embodiments, equations can be used, where one equation calculates tilt angle as a function of proximity amount and other equation calculates tilt direction as a function of relative position. Other orientation calculation methods are also possible according to various embodiments. 
     A determination can be made of which of the second electrodes is closest to the contacting surface ( 850 ). In some embodiments, the relative strengths of the capacitance images of the second electrodes in the captured image can be estimated and the electrode with the strongest capacitance image magnitude determined to be the one closest to the contacting surface. 
     The stylus rotation can then be calculated based on the determination ( 860 ). In some embodiments, the rotation calculation can include detecting the capacitances of each second electrode over a particular time period, comparing each second electrode&#39;s capacitance images over the time period, and determining each second electrode&#39;s capacitance image magnitude change over that time period. A capacitance image increase of a particular second electrode can indicate a rotation of that electrode toward the contacting surface. Conversely, a capacitance image decrease of a particular second electrode can indicate a rotation of that electrode away from the contacting surface. The amount and direction of the image changes and the second electrodes involved can indicate the amount and direction of the rotation. For example, if one of the second electrodes experiences a small capacitance increase and an adjacent (in a clockwise direction) second electrode experiences a small capacitance decrease, e.g., as shown by a respective increase and decrease of image magnitudes, it can be determined that the stylus made a small rotation clockwise. Similar determinations can be made for a large capacitance increase and concurrent capacitance decrease in these respective electrodes. Conversely, if one of the second electrodes experiences a small capacitance decrease and an adjacent (in a clockwise direction) second electrode experiences a small capacitance increase, e.g., as shown by a respective decrease and increase of image magnitudes, it can be determined that the stylus made a small rotation counterclockwise. Similar determinations can be made for a large capacitance decrease and concurrent capacitance increase in these respective electrodes. In some embodiments, a lookup table can be used, where the table&#39;s entries include a capacitance change amount-rotation amount pairing. The capacitance change amount for the appropriate second electrodes can be inputted to the lookup table and the corresponding rotation amount outputted therefrom. 
     In some embodiments, rather than using image magnitude changes as described in the previous paragraph, image position changes can be used to determine the stylus rotation. As such, the rotation calculation can include detecting the capacitances of each second electrode over a particular time period, comparing each second electrode&#39;s capacitance images over the time period, and determining each second electrode&#39;s capacitance image position change over that time period. A capacitance image clockwise shift of a particular second electrode can indicate a clockwise rotation of the stylus. Conversely, a capacitance image counterclockwise shift of a particular second electrode can indicate a counterclockwise rotation of stylus. The amount and direction of the image shift and the second electrodes involved can indicate the amount and direction of the stylus rotation. For example, if one of the second electrodes experiences a small clockwise shift, e.g., as shown by a small shift in the capacitance image in the captured images, it can be determined that the stylus made a small rotation clockwise. Similar determinations can be made for a large clockwise rotation. Conversely, if one of the second electrodes experiences a small counterclockwise shift, e.g., as shown by a small shift in the capacitance image in the captured images, it can be determined that the stylus made a small rotation counterclockwise. Similar determinations can be made for a large counterclockwise rotation. In some embodiments, a lookup table can be used, where the table&#39;s entries include a capacitance image shift amount-rotation amount pairing. The capacitance image shift amount for the appropriate second electrodes can be inputted to the lookup table and the corresponding rotation amount outputted therefrom. 
       FIG. 9  illustrates an exemplary stylus having an orientation sensor for use with a touch panel also having an orientation sensor according to various embodiments. In the example of  FIG. 9 , stylus  910  can include orientation sensor  919  for detecting the stylus orientation relative to a reference, e.g., the earth. In some embodiments, the sensor  919  can be an accelerometer, a gyroscope, a magnetometer, and the like. Touch panel  920  can orientation sensor  929  for detecting the panel orientation relative to the reference. In some embodiments, the sensor  929  can be an accelerometer, a gyroscope, a magnetometer, and the like. Here, the orientation of the stylus  910  can be determined relative to the orientation of the panel  920 , which can be mobile. 
       FIG. 10  illustrates another exemplary method for detecting an orientation of a stylus according to various embodiments. This method can be used with the stylus of  FIG. 9 , for example. In the example of  FIG. 10 , a sensor in a stylus can detect the stylus orientation relative to a reference, e.g., the earth ( 1010 ). A sensor in a mobile touch panel can detect the panel orientation also relative to the reference ( 1020 ). The orientation of the stylus relative to the panel can then be calculated based on the two sensed orientations ( 1030 ). In some embodiments, the calculation can include the stylus transmitting its sensor reading via wired or wireless communication to a processor, the panel transmitting its sensor reading also to the processor, and the processor calculating the orientation of the stylus based on the two transmitted orientations. In some embodiments, the processor can be in the panel, in a touch sensitive device incorporating the panel, or in a host device. In some embodiments, the calculation can be done on the stylus processor with the panel transmitting its sensor reading to the stylus. The stylus can then transmit its calculated orientation back to the panel processor, the touch sensitive device processor, or the host device processor. 
     In some embodiments, the stylus can include a second sensor to detect its orientation relative to the reference. In some embodiments, the second sensor can be a gyroscope, a magnetometer, or the like. The sensor readings from the two sensors in the stylus can then be compared to verify the orientation of the stylus. The use of the second sensor can be particularly helpful to prevent false or noisy stylus orientation readings caused by small inadvertent movement of the stylus. 
       FIG. 11  illustrates an exemplary stylus tip having strip electrodes according to various embodiments. In the example of  FIG. 11 , tip  1112  can have electrode  1114  at a distal end for contacting a surface and strip electrodes  1116 -A,  1116 -B,  1116 -C proximate to the distal end and aligned in parallel around the tip. The strip electrodes can perform in a similar manner as the segment electrodes of  FIGS. 6   a  and  6   b . Although  FIG. 11  depicts three strip electrodes, it is to be understood that any other number of multiple electrodes can be used according to various embodiments. 
       FIG. 12  illustrates an exemplary stylus tip having a wide ring electrode according to various embodiments. This stylus tip is similar to that of  FIGS. 2   a  and  2   b  with the exception that ring electrode  1216  in  FIG. 12  is wider. The wider ring electrode can perform in a similar manner as the ring electrode of  FIGS. 2   a  and  2   b.    
       FIG. 13  illustrates an exemplary stylus flat tip according to various embodiments. In the example of  FIG. 13 , two electrodes  1314 ,  1316  can be placed side by side to form stylus tip  1312 . A distal end of each electrode  1314 ,  1316  can be flattened to form the stylus flat tip. 
     To detect the orientation of a stylus having the flat tip of  FIG. 13 , an image of the capacitances at the electrodes  1314 ,  1316  can be captured. In a perpendicular orientation, the image can produce a substantially symmetric capacitance image. As the stylus tilts, the image can produce an asymmetric capacitance image. The amount of asymmetry can indicate the amount of tilt. The direction of the tilt can be determined from the direction of the asymmetry in the capacitance image. By determining the asymmetry and its direction, the stylus tilt angle and tilt direction can be determined. 
     In addition, the stylus rotation can be determined. This determination can include detecting the capacitances of the two electrodes  1314 ,  1316  over a particular time period, comparing each electrode&#39;s capacitances over the time period, and determining each electrode&#39;s capacitance change over that time period. A capacitance increase of a particular electrode can indicate a rotation of that electrode toward the contacting surface. Conversely, a capacitance decrease of a particular electrode can indicate a rotation of that electrode away from the contacting surface. 
     As described previously, the stylus can act as a driving element, a sensing element, or both. 
       FIG. 14   a  illustrates a side view of an exemplary stylus according to various embodiments. In the example of  FIG. 14   a , stylus  1410  can include shaft  1418  and tip  1412 . The tip  1412  can include electrode  1414  forming the entire tip for contacting a surface. The stylus  1410  of  FIG. 14   a  is like the stylus  210  of  FIG. 2   a , except that the tip electrode  214  and the ring electrode  216  of  FIG. 2   a  are replaced with the single large electrode  1414  of  FIG. 14   a.    
       FIG. 14   b  illustrates a bottom view of the exemplary stylus of  FIG. 14   a  according to various embodiments. In the example of  FIG. 14   b , stylus  1410  can have a conical shaped tip  1412  with electrode  1414  forming the entire tip. 
       FIGS. 15   a  and  15   b  illustrate various orientations of the exemplary stylus of  FIGS. 14   a  and  14   b  as it touches a touch panel according to various embodiments. In the example of  FIG. 15   a , stylus  1510  can have a perpendicular orientation as it touches touch panel  1520 . As the stylus  1510  touches the panel  1520 , electrode  1514  can form capacitance C 1  with a proximate conductive element, e.g., row(s) and/or column(s), (not shown) of the panel. Image  1530  captured at the panel  1520  can show touch or hover images resulting from the capacitance C 1 . Because the stylus  1510  is perpendicular to the panel  1520 , the image  1530  can show the capacitance C 1  image as a small circle. 
     In the example of  FIG. 15   b , the stylus  1510  can have a tilted orientation as it touches the panel  1520 . As a result, the image  1530  captured at the panel  1520  can show a triangular shape and larger size in the touch or hover image resulting from capacitance C 1 . The shape and size of the capacitance C 1  image can be a function of the amount of stylus tilt. For example, the greater the tilt, the larger and more triangular the capacitance C 1  image shape. Conversely, the lesser the tilt, the smaller and more circular the capacitance C 1  image shape. Therefore, by determining the shape and size of the capacitance C 1  image in the captured image, the amount of stylus tilt (e.g., the tilt angle) can be determined. 
     The image  1530  can also be used to determine the direction of the stylus tilt, e.g., upward, downward, right, left, and so on, relative to the touch panel  1520 . For example, in the image  1530  of  FIG. 15   b , the capacitance C 1  image has a triangular shape with the triangle base to the right of the triangle apex in the captured image  1530 . This can indicate that the stylus  1510  is tilted to the right. If the capacitance C 1  image has a triangular shape with the base to the left of the apex in the captured image  1530 , this can indicate that the stylus  1510  is tilted to the left. Other tilt directions, e.g., upward, downward, upper left, lower right, etc., can also be determined according to the direction of the capacitance C 1  image&#39;s triangular base. 
     By determining the size and shape in an image, the stylus orientation, e.g., the tilt angle and the tilt direction, can be detected. 
       FIG. 16  illustrates another exemplary method for detecting an orientation of a stylus according to various embodiments. This method can be used with the stylus of  FIGS. 14   a  and  14   b , for example. In the example of  FIG. 16 , a capacitance formed between a stylus electrode and a contacting surface can be detected ( 1610 ). In some embodiments, the electrode can be a single large electrode that forms the stylus tip. In some embodiments, the capacitance detection can include capturing an image that can show touch or hover images resulting from the capacitance at the touch panel and performing a suitable image processing method on the captured image to determine the location of the capacitance image therein. 
     The size and shape of the detected capacitance image in the captured image can be determined ( 1620 ). In some embodiments, performing a suitable image processing method on the captured image can determine the size and shape of the capacitance image. 
     The stylus orientation can then be calculated based on the determination ( 1630 ). In some embodiments, the orientation calculation can include determining the tilt angle based on the determined size and shape of the capacitance image and determining the direction of the stylus tilt based on the location of the triangular base relative to the triangle apex of the capacitance image. In some embodiments, lookup tables can be used, where one table&#39;s entries include a tilt angle-shape-size pairing and another table&#39;s entries includes a tilt direction-base location pairing. The shape, size, and base locations could be inputted to the lookup tables and the corresponding tilt angle and tilt direction outputted therefrom. In some embodiments, equations can be used, where one equation calculates tilt angle as a function of shape and size and another equation calculates tilt direction as a function of triangular base location. Other orientation calculation methods are also possible according to various embodiments. 
       FIG. 17  illustrates exemplary drive circuitry of a stylus according to various embodiments. In the example of  FIG. 17 , stylus  1710  can house drive circuitry to drive the stylus to capacitively couple with proximate conductive elements of a touch panel. The conductive elements can then output capacitance readings for further processing. The stylus driving circuitry can include clock  1740  to provide a drive signal, microcontroller  1750  to control the drive signal, amplifier  1764  to gain up the clock signal to electrode  1714 , and amplifier  1766  to gain up the clock signal to electrode  1716 . In some embodiments, electrode  1714  can be an electrode at the distal end of the stylus tip and electrode  1716  can be one or more electrodes proximate to the distal end of the stylus tip and placed around the stylus tip. In some embodiments, the signals to the two electrodes  1714 ,  1716  can be the same. In some embodiments, the signals to the two electrodes  1714 ,  1716  can be different in order to differentiate between them. 
       FIG. 18  illustrates exemplary sense circuitry of a stylus according to various embodiments. In the example of  FIG. 18 , stylus  1810  can house sense circuitry to sense a capacitance from proximate conductive elements of a touch panel capacitively coupled to the stylus. The stylus can output the capacitance readings for further processing. The stylus sensing circuitry can include amplifier  1870  to receive the capacitance reading from the panel, clock  1840  to generate a demodulation signal, phase shifter  1845  to generate a phase-shifted demodulation signal, mixer  1883  to demodulate the capacitance reading with an in-phase demodulation frequency component, and mixer  1887  to demodulate the capacitance reading with a quadrature demodulation frequency component. The demodulated results can be further processed according to various embodiments. 
     In some embodiments, a stylus can house both driving and sensing circuitry and can include a switching mechanism couple between the two circuits for switching between driving and sensing according to the requirements of the system in which the stylus is used. 
       FIG. 19  illustrates an exemplary computing system that can use a stylus according to various embodiments. In the example of  FIG. 19 , computing system  1900  can include touch controller  1906 . The touch controller  1906  can be a single application specific integrated circuit (ASIC) that can include one or more processor subsystems  1902 , which can include one or more main processors, such as ARM968 processors or other processors with similar functionality and capabilities. However, in other embodiments, the processor functionality can be implemented instead by dedicated logic, such as a state machine. The processor subsystems  1902  can also include peripherals (not shown) such as random access memory (RAM) or other types of memory or storage, watchdog timers and the like. The touch controller  1906  can also include receive section  1907  for receiving signals, such as touch (or sense) signals  1903  of one or more sense channels (not shown), other signals from other sensors such as sensor  1911 , etc. The touch controller  1906  can also include demodulation section  1909  such as a multistage vector demodulation engine, panel scan logic  1910 , and transmit section  1914  for transmitting stimulation signals  1916  to touch panel  1924  to drive the panel. The scan logic  1910  can access RAM  1912 , autonomously read data from the sense channels, and provide control for the sense channels. In addition, the scan logic  1910  can control the transmit section  1914  to generate the stimulation signals  1916  at various frequencies and phases that can be selectively applied to rows of the touch panel  1924 . 
     The touch controller  1906  can also include charge pump  1915 , which can be used to generate the supply voltage for the transmit section  1914 . The stimulation signals  1916  can have amplitudes higher than the maximum voltage by cascading two charge store devices, e.g., capacitors, together to form the charge pump  1915 . Therefore, the stimulus voltage can be higher (e.g., 6V) than the voltage level a single capacitor can handle (e.g., 3.6 V). Although  FIG. 19  shows the charge pump  1915  separate from the transmit section  1914 , the charge pump can be part of the transmit section. 
     Computing system  1900  can include host processor  1928  for receiving outputs from the processor subsystems  1902  and performing actions based on the outputs that can include, but are not limited to, moving an object such as a cursor or pointer, scrolling or panning, adjusting control settings, opening a file or document, viewing a menu, making a selection, executing instructions, operating a peripheral device coupled to the host device, answering a telephone call, placing a telephone call, terminating a telephone call, changing the volume or audio settings, storing information related to telephone communications such as addresses, frequently dialed numbers, received calls, missed calls, logging onto a computer or a computer network, permitting authorized individuals access to restricted areas of the computer or computer network, loading a user profile associated with a user&#39;s preferred arrangement of the computer desktop, permitting access to web content, launching a particular program, encrypting or decoding a message, and/or the like. The host processor  1928  can also perform additional functions that may not be related to touch processing, and can be connected to program storage  1932  and display device  1930  such as an LCD for providing a UI to a user of the device. Display device  1930  together with touch panel  1924 , when located partially or entirely under the touch panel, can form a touch screen. 
     Touch panel  1924  can include a capacitive sensing medium having drive lines and sense lines. It should be noted that the term “lines” can sometimes be used herein to mean simply conductive pathways, as one skilled in the art can readily understand, and is not limited to structures that can be strictly linear, but can include pathways that change direction, and can include pathways of different size, shape, materials, etc. Drive lines can be driven by stimulation signals  1916  and resulting touch signals  1903  generated in sense lines can be transmitted to receive section  1907  in touch controller  1906 . In this way, drive lines and sense lines can be part of the touch and hover sensing circuitry that can interact to form capacitive sensing nodes, which can be thought of as touch picture elements (touch pixels), such as touch pixels  1926 . This way of understanding can be particularly useful when touch panel  1924  can be viewed as capturing an “image” of touch. In other words, after touch controller  1906  has determined whether a touch or hover has been detected at each touch pixel in the touch panel, the pattern of touch pixels in the touch panel at which a touch or hover occurred can be thought of as an “image” of touch (e.g. a pattern of fingers touching or hovering over the touch panel). 
     A stylus according to various embodiments can be used to contact the touch panel  1924 . The stylus orientation can provide additional information to the computing system  1900  for improved performance. 
     Note that one or more of the functions described above, can be performed, for example, by firmware stored in memory (e.g., one of the peripherals) and executed by the processor subsystem  1902 , or stored in the program storage  1932  and executed by the host processor  1928 . The firmware can also be stored and/or transported within any non-transitory computer readable storage medium for use by or in connection with an instruction execution system, apparatus, or device, such as a computer-based system, processor-containing system, or other system that can fetch the instructions from the instruction execution system, apparatus, or device and execute the instructions. In the context of this document, a “non-transitory computer readable storage medium” can be any medium that can contain or store the program for use by or in connection with the instruction execution system, apparatus, or device. The non-transitory computer readable storage medium can include, but is not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus or device, a portable computer diskette (magnetic), a random access memory (RAM) (magnetic), a read-only memory (ROM) (magnetic), an erasable programmable read-only memory (EPROM) (magnetic), a portable optical disc such a CD, CD-R, CD-RW, DVD, DVD-R, or DVD-RW, or flash memory such as compact flash cards, secured digital cards, USB memory devices, memory sticks, and the like. 
     The firmware can also be propagated within any transport medium for use by or in connection with an instruction execution system, apparatus, or device, such as a computer-based system, processor-containing system, or other system that can fetch the instructions from the instruction execution system, apparatus, or device and execute the instructions. In the context of this document, a “transport medium” can be any medium that can communicate, propagate or transport the program for use by or in connection with the instruction execution system, apparatus, or device. The transport readable medium can include, but is not limited to, an electronic, magnetic, optical, electromagnetic or infrared wired or wireless propagation medium. 
     It is to be understood that the touch panel, as described in  FIG. 19 , can sense touch and hover according to various embodiments. In addition, the touch panel described herein can be either single- or multi-touch. 
       FIG. 20  illustrates an exemplary mobile telephone  2030  that can include touch panel  2024 , display device  2036 , and other computing system blocks for use with a stylus according to various embodiments. 
       FIG. 21  illustrates an exemplary digital media player  2130  that can include touch panel  2124 , display device  2136 , and other computing system blocks for use with a stylus according to various embodiments. 
       FIG. 22  illustrates an exemplary personal computer  2230  that can include touch pad  2224 , display  2236 , and other computing system blocks for use with a stylus according to various embodiments. 
     The mobile telephone, media player, and personal computer of  FIGS. 20 through 22  can improve touch and hover sensing and preserve power by utilizing a stylus according to various embodiments. 
     Although embodiments have been fully described with reference to the accompanying drawings, it is to be noted that various changes and modifications will become apparent to those skilled in the art. Such changes and modifications are to be understood as being included within the scope of the various embodiments as defined by the appended claims.

Metadata:
Filing Date: 20110622
Publication Date: 20140128
Grant Date: 20140128
Priority Date: 20110622
Inventors: HARLEY JONAH A.
TAN LI-QUAN
MUKHERJEE DEBANJAN
HOTELLING STEVEN PORTER
Assignee: APPLE INC
CPC Classifications: [{"code": "G06F3/0441", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/0442", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/03545", "inventive": true, "first": true, "tree": "[]"}, {"code": "G06F3/0441", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/03545", "inventive": true, "first": true, "tree": "[]"}, {"code": "G06F3/0442", "inventive": true, "first": false, "tree": "[]"}]
Family ID: 46420547