Abstract:
An electronic device described herein includes a touch screen for a touch sensitive display carried by a portable housing. The electronic device is configured to operate in a high. detection threshold mode to determine whether an object is in contact with the touch sensitive display, and operate in a low detection threshold mode to determine whether the object is adjacent to the touch sensitive display, based on lack of detection of the object being in contact with the touch sensitive display. The electronic device is further configured to determine whether the object is in contact with a peripheral edge of the portable housing by determining whether the object is adjacent opposite sides of the touch sensitive display, based on detection of the object being adjacent to the touch sensitive display.

Description:
PRIORITY CLAIM 
       [0001]    This application claims priority from Chinese Application for Patent No. 201610266876.X filed Apr. 26, 2016, the disclosure of which is incorporated by reference. 
       TECHNICAL FIELD 
       [0002]    The present disclosure relates generally to touch screens and more specifically to techniques for determining a relationship between a user&#39;s hand and a housing of an electronic device. 
       BACKGROUND 
       [0003]    Touch screens are present in many different types of common modern electronic devices, such as smartphones, tablets, smartwatches, wearables, laptop computers, and so on. In these electronic devices the touch screen serves as an output device as well as an input device. The touch screen typically includes display layer and a sensing layer. A touch screen controller is coupled to the sensing layer and operates to process signals therefrom to detect inputs by a user. The sensing layer includes touch sensors, and is attached to or formed as an integral part of the display layer, which may be a LCD, IPS, or AMOLED display, for example. 
         [0004]    A typical sensing layer of a touch screen is a capacitive sensor array including a number of force or drive lines and orthogonally arranged sense lines. These lines are made from suitable conductive materials, the drive lines are formed on one sub-layer of the sensing layer and the sense lines formed on another sub-layer, with these sub-layers being separated by a transparent insulating material such as an insulating dielectric layer. The overlap of the drive lines and the orthogonally arranged sense lines with the insulating material between forms an array of capacitive sensors. In operation, a drive signal, which is typically a periodic waveform such as a pulse train, is applied successively to the drive lines. As the drive signal is applied to a given drive line, the capacitive coupling between that drive line and the sense lines results in capacitive coupling of the drive signal to the sense lines to thereby generate sense signals on the sense lines responsive to the drive signal. 
         [0005]    The value of the sense signal generated on each sense line is a function of the capacitive coupling between that sense line and the drive line receiving the drive signal. This capacitive coupling changes in response to a user&#39;s hand being proximate the sensor nodes formed at the overlap of the drive and sense lines. This change in capacitive coupling of the drive signal to the sense lines will result in a change in the sense signal generated on the sense lines, and in this way the sense signals indicate whether a user&#39;s finger or other touch device is adjacent a given sensor node in the touch panel. 
         [0006]    In operation, a user touches a surface of the touch panel or hovers his or her finger above the touch panel, and the capacitive sensors generate corresponding electronic sensor signals that are provided to the touch screen controller. From these sensor signals, the touch screen controller determines touch data values (referred to as strength values), from these strength values determines the type of touch event or hover event input by the user to the touch screen, and then provides this information to processing circuitry, such as a host controller, in the electronic device. 
         [0007]    As devices incorporating touch screens grow more complex in functionality provided, the providing of additional input paradigms to a user is desirable. Since users are now accustomed to using touch based interfaces, it is desirable to develop new ways of using the capacitive sensors in a touch panel to form new user interface paradigms, and also to provide information about the way the user is interfacing with the device (i.e. holding the device, laying the device flat on a surface, etc.) to the processing circuitry. 
       SUMMARY 
       [0008]    An electronic device described herein includes a touch screen for a touch sensitive display carried by a portable housing. The electronic device is configured to operate in a high detection threshold mode to determine whether an object is in contact with the touch sensitive display, and operate in a low detection threshold mode to determine whether the object is adjacent to the touch sensitive display, based on lack of detection of the object being in contact with the touch sensitive display. The electronic device is further configured to determine whether the object is in contact with a peripheral edge of the portable housing by determining whether the object is adjacent opposite sides of the touch sensitive display, based on detection of the object being adjacent to the touch sensitive display. 
         [0009]    Another aspect is directed to an electronic device including a portable housing with a touch sensitive display carried by the portable housing, the touch sensitive display including a plurality of sense lines. A touch screen controller is coupled to the plurality of sense lines and configured to operate in a screen touch detection mode to detect a user&#39;s hand being in contact with the touch sensitive display as a function of reading strength values from at least sonic of the plurality of sense lines. In the screen touch detection mode, the user&#39;s hand is detected as being in contact with the touch sensitive display as a function of read strength values being greater than a first threshold. 
         [0010]    The touch screen controller is configured to operate in a portable housing touch detection mode to detect the user&#39;s hand being adjacent to the touch sensitive display, based on lack of detection of the user&#39;s hand being in contact with the touch sensitive display and as a function of reading strength values from at least some of the plurality of sense lines. In the portable housing touch detection mode, the user&#39;s hand is detected as being adjacent to the touch sensitive display as a function of read strength values being greater than a second threshold, where the second threshold is less than the first threshold. The touch screen controller is also configured to determine whether the user&#39;s hand is in contact with the portable housing by detecting whether the user&#39;s hand is adjacent opposite sides of the touch sensitive display, based on detection of the user&#39;s hand being adjacent to the touch sensitive display. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]      FIG. 1  is a block diagram of an electronic device on which the techniques described herein may be implemented. 
           [0012]      FIG. 2  is a cutaway view of the touch sensitive display of the touch screen of  FIG. 1  showing the components thereof. 
           [0013]      FIG. 3  is a schematic block diagram of the touch screen controller of  FIG. 1 , and its interconnection with the sense and drive lines of the touch sensing layer of the touch sensitive display of  FIG. 2 . 
           [0014]      FIG. 4  is a flowchart describing operation of techniques for determining the relationship between a user&#39;s hand and a portable housing of an electronic device such as that shown in  FIG. 1 , in accordance with this disclosure. 
           [0015]      FIGS. 5A-5C  illustrate a first technique for determining that a user&#39;s hand is gripping the portable housing of the electronic device. 
           [0016]      FIGS. 6A-6D  illustrate a technique for determining that a user&#39;s hand is gripping the portable housing of the electronic device where the user initially grips the housing with two fingers, and thereafter adds another finger to the grip. 
           [0017]      FIGS. 7A-7D  illustrate a first technique for detecting that a user has tapped the portable housing of the electronic device. 
           [0018]      FIGS. 8A-8C  illustrate a second technique for detecting that a user has tapped the portable housing of the electronic device. 
           [0019]      FIGS. 9A-9C  illustrate a technique for detecting that a user has performed a gesture on the portable housing of the electronic device. 
           [0020]      FIG. 10  illustrates the profile of strength values determined from the sense lines of the electronic device when a user is gripping the portable housing of the electronic device. 
           [0021]      FIG. 11  illustrates the profile of strength values determined from the sense lines of the electronic device when a user is hovering a finger over the touch screen of the electronic device. 
           [0022]      FIG. 12  illustrates a first technique for determining whether a user is gripping the portable housing of the electronic device or whether the user is hovering a finger over the touch screen of the electronic device. 
           [0023]      FIG. 13  illustrates a second technique for determining whether a user is gripping the portable housing of the electronic device or whether the user is hovering a finger over the touch screen of the electronic device. 
       
    
    
     DETAILED DESCRIPTION 
       [0024]    The present description is made with reference to the accompanying drawings, in which example embodiments are shown. However, many different embodiments may be used, and thus the description 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. Like numbers refer to like elements throughout. 
         [0025]    With initial reference to  FIGS. 1-3  an electronic device  100  is now described. The electronic device  100  may be a smartphone, smartwatch, wearable, tablet, laptop, or other suitable portable electronic device. The electronic device  100  includes a host controller  102  that receives input from a touch screen controller  106 , which itself receives input from a touch screen  104 . The output provided by the touch screen controller  106  to the host controller  102  as input includes information such as locations of touches on the touch screen  104 , whether the touch screen  104  was tapped and where, the location and type of gesture performed on the touch screen  104 , etc. 
         [0026]    The touch screen  104  includes a display layer  114 , with a touch sensing layer  116  adjacent thereto. The touch sensing layer  116  includes drive lines D 1 -D 4  that intersect sense lines S 1 -S 4  at some locations. The sense lines S 1 -S 4  are coupled to the touch screen controller  106 , while the drive lines D 1 -D 4  are coupled to drive circuitry  118 . At each intersection point between the drive line D 1  and the sense lines S 1 -S 4 , a capacitance is formed. 
         [0027]    In operation, the driving circuitry  118  drives the drive lines D 1 -D 4  with periodic signals, such as sine waves or square waves. At certain intersection points between the drive lines D 1 -D 4  and the sense lines S 1 -S 4 , touch sensors are formed, the respective sense line S 1 -S 4  incurs a charge injection proportional to the voltage at the drive lines D 1 -D 4 , and a capacitance between the respective sense line S 1 -S 4  and the drive lines D 1 -D 4  is at the sensor of that intersection point. These capacitances vary in proximity to conductive objects, such as human fingers and styluses, and are measured by the touch screen controller  106  and processed to be touch data values stored in a matrix having entries that correspond to the various intersections of the drive lines D 1 -D 4  with the sense lines S 1 -S 4 . 
         [0028]    In some scenarios, it may be desirable for the host controller  102  to receive information regarding the relationship between the user&#39;s hand and the portable housing  101  of the electronic device  100 . To that end, the touch screen controller  106  of this disclosure is capable of operating in a high detection threshold mode and a low detection threshold mode. In the high detection threshold mode, the strength measurement on a sense line that results in the registering of a touch is greater than the strength measurement on a sense line that results in the registering of a touch in the low detection threshold mode. Stated another way, in the low detection threshold mode, the gain or sensitivity of the touch screen controller  106  is increased so as to enable detection of the user&#39;s hand (or stylus, in some applications) in contact with the portable housing  101  but not with the touch screen  104 ; in the high detection threshold mode, the gain or sensitivity is decreased as to enable precise detection of the location of a touch of the user&#39;s hand on the touch screen  104 . 
         [0029]    Operation of this touch screen controller  106  will now be described with initial reference to  FIG. 4 . Here, the touch screen controller  106  enters the high detection threshold mode with a decreased gain/sensitivity (Block  202 ), and then scans the sense lines S 1 -S 4  (Block  204 ) for strength values. Where a touch is detected (Block  206 ), the touch screen controller then processes those strength values (Block  208 ) and ultimately generates data for use by the host controller  102 . Where a touch is not detected, the host controller  102  causes the touch screen controller  106  (Block  209 ) to enter into a low detection threshold mode with an increased gain/sensitivity (Block  210 ). 
         [0030]    Once in the low detection threshold mode, the touch screen controller  106  then scans one or more sense lines S 1 , S 4  adjacent the sides of the touch screen  104  (Block  212 ), but does not scan sense lines S 2 , S 3  that are not adjacent the sides of the touch screen  104 . The touch screen controller  106  then processes the resulting strength values to determine whether a touch to the side of the portable housing  101  of the electronic device  100  has been made (Block  214 ). That information is then passed to the host controller  102 , and the touch screen controller  106  then returns to the high detection threshold mode (Block  202 ). This described process then repeats. 
         [0031]    It should be noted that in some cases in the low detection threshold mode, the touch screen controller  106  drives one or more of the force lines D 1 , D 4  adjacent the sides of the touch screen  104  instead, but does not drive force lines D 2 , D 3  that are not adjacent the sides of the touch screen. The touch screen controller  106 , in this mode, scans each sense line S 1 -S 4 . The touch screen controller  106  then processes the resulting strength values to determine whether a touch to the side of the portable housing  101  of the electronic device  100  has been made (Block  214 ). That information is then passed to the host controller  102 , and the touch screen controller  106  then returns to the high detection threshold mode (Block  202 ). This described process then repeats. 
         [0032]    Thus, as has been described, the touch screen controller  106  switches back and forth between the high detection threshold mode and the low detection threshold mode. It should be understood that the touch screen controller  106  may spend equal amounts of time (or clock cycles) in each of these modes, or may spend more time (or clock cycles) in one mode than in another mode. 
         [0033]    By analyzing the strength values obtained when the user&#39;s hand is adjacent to but not touching the touch screen  104 , the touch screen controller  106  or host controller  102  can determine whether the user is gripping the portable housing  101 , whether the user has tapped the portable housing  101 , or whether the user has performed a gesture on the portable housing  101 . 
         [0034]    Before this stage of the analysis or processing is performed though, it may be helpful to determine whether the user&#39;s hand is actually in contact with the portable housing  101 , or whether the user is hovering a finger over the touch screen  104 . 
         [0035]    As can be seen on  FIG. 10 , when gripping the portable housing  101 , the user is typically gripping on opposing sides, which results in the illustrated strength profile. However, when the user is merely hovering a finger over the touch screen  104 , the resulting strength profile is as shown in  FIG. 11 . By determining which strength profile is read by the touch screen controller  106 , the difference between a grip and a hover can thereby be determined. 
         [0036]    One way to make the determination of which strength profile the readings of the sense lines S 1 -S 4  best fits is by comparing the strengths of the two sense lines most adjacent a given side (or in the case where all sense lines S 1 -S 4  are read but not all force or drive lines D 1 -D 4  are driven, the reading of each sense line when two drive lines most adjacent the given side are activated). If the strength of the sense line most adjacent a given side (or the strength of each sense line when the drive line most adjacent the given side is activated) is above a given threshold (as shown in  FIG. 12 , value 80), and the strength of the sense line adjacent that sense line (or the strength of each sense line when the drive line adjacent the drive line most adjacent the given side is activated) is below a given threshold (as shown in  FIG. 12 , value 50), and this strength remains for a given period of time, the touch screen controller  106  or host controller  102  can determine that the user is gripping the portable housing  101  of the electronic device  100 . 
         [0037]    Likewise, if the strength of the sense line most adjacent a given side (or the strength of each sense line when the drive line most adjacent the given side is activated) is above a given threshold and the strength of the sense line adjacent that sense line (or the strength of each sense line when the drive line adjacent the drive line most adjacent the given side is activated) is below a given threshold, and if a similar pattern is present for the opposite side, then the touch screen controller  106  or host controller  102  can determine that the user is gripping the portable housing  101  of the electronic device  100 . However, if the strength of the two sense lines (for example, S 3 -S 4 ) is similar (or if the strength of each sense line as two drive lines are activated), with both being above their respective thresholds, then the touch screen controller  106  or host controller  102  can determine that the user is hovering a finger over the touch screen  104 . 
         [0038]    Rather than having the second threshold be a set value, the second threshold may instead be a set percentage of a maximum possible strength reading of the sense line most adjacent the side of the touch screen  104 , as shown in  FIG. 13 . 
         [0039]    In either case, where a hover is detected, data values representing the location of the hovering finger over the touch screen  104  may be determined by the touch screen controller  106  and sent to the host controller  102 . Alternatively, these data values may not be sent. 
         [0040]    With reference to the series shown in  FIGS. 5A-5C , a first technique for determining that a user is gripping the portable housing  101  of the electronic device  100  is now described. Here, once the touch screen controller  106  detects strength values of the sense lines that could indicate that a user&#39;s hand is gripping the portable housing  101  ( FIG. 5A ), it defines boundaries about the locations where those strength values indicate parts of the user&#39;s hand may be ( FIG. 5B ). If those parts of the hand stay within those boundaries for a given period of time, then the fact that the user is gripping the portable housing  101  is determined ( FIG. 5C ). 
         [0041]    In some cases, the user may initially grip the portable housing  101  with a first number of fingers, and then later add one or more fingers to the grip. Such a scenario is depicted in the series shown in  FIGS. 6A-6D , where the user initially grasps the portable housing  101  with a first set of fingers ( FIG. 6A ), then later adds another finger ( FIG. 6B ). In this case, the touch screen controller  106  may then define a new boundary for the newly added finger ( FIG. 6C ), and if that newly added finger stays within the new boundary for a given period of time, then the grip detection may change to be a grip that includes the newly added finger ( FIG. 6D ). 
         [0042]    Tap detection is now described with reference to the series shown in  FIGS. 7A-7D . Here, once the touch screen controller  106  detects strength values of the sense lines that could indicate that a user&#39;s hand is gripping the portable housing  101 , it defines boundaries about the locations where those strength values indicate parts of the user&#39;s hand may be ( FIG. 7A ). If a finger is removed from within one of these boundaries ( FIG. 7B ), and then returned to the proper boundary for a given period of time ( FIG. 7C ), and then removed from that boundary again, a tap is detected ( FIG. 7D ). In some applications, the boundary for detection of a tap may be different than the boundary for grip detection. 
         [0043]    Another technique for tap detection is described with reference to the series of  FIGS. 8A-8C . Here, once the touch screen controller  106  detects strength values of the sense lines that could indicate that a user&#39;s hand is gripping the portable housing  101 , it defines boundaries about the locations where those strength values indicate parts of the user&#39;s hand may be ( FIG. 8A ). If a finger is then added as indicated by strength values, the touch screen controller  106  adds a boundary for the added finger ( FIG. 8B ). If that finger is present for a given period of time, and then it leaves the side, a tap or side tap is detected ( FIG. 8C ). 
         [0044]    As explained above, gesture detection may also be performed by the touch screen controller  106 . This is now described with reference to the series shown in  FIGS. 9A-9C . Here, once the touch screen controller  106  detects strength values of the sense lines that could indicate that a user&#39;s hand is gripping the portable housing  101 , it defines boundaries about the locations where those strength values indicate parts of the user&#39;s hand may be ( FIG. 9A ). 
         [0045]    If a finger leaves a defined boundary ( FIG. 9B ), and then returns to the defined boundary within a given period of time ( FIG. 9C ), then a gesture or side gesture (here, a sliding motion) is detected. 
         [0046]    Many modifications and other embodiments 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 various modifications and embodiments are intended to be included within the scope of the appended claims.