(12) INTERNATIONAL APPLICATION PUBLISHED UNDER THE PATENT COOPERATION TREATY(PCT)
`(19) World Intellectual Property
`Organization
`International Bureau
`
`UREAREID ETAT TTA
`
`(10) International Publication Number
`(43) International Publication Date
`WO 2013/155098 Al
`17 October 2013 (17.10.2013) WIPO|PCT
`
`
`\Z
`
`GD
`
`International Patent Classification:
`GO6F3/044 (2006.01)
`
`@D
`
`International Application Number:
`
`PCT/US2013/035824
`
`(22)
`
`International Filing Date:
`
`@5)
`
`(26)
`
`G0)
`
`(7)
`
`Filing Language:
`
`Publication Language:
`
`9 April 2013 (09.04.2013)
`
`English
`
`English
`
`Priority Data:
`61/621,809
`13/621,830
`
`9 April 2012 (09.04.2012)
`17 September 2012 (17.09.2012)
`
`TECHNOLOGIES,
`AMAZON
`Applicant!)
`[US/US]; P.O. Box 8102, Reno, Nevada 89507 (US).
`
`US
`US
`
`INC.
`
`Inventors: OBETDAT, Amjad T.; 410 Terry Ave. North,
`Seattle, Washington 98107 (US). PANCE, Aleksander;
`410 Terry Ave. North, Seattle, Washington 98107 (US).
`
`Agents: LOHR, Jason D. et al; Novak Druce Connolly
`Bove + Quigg LLP, 1000 Lousiana Street, Fifty-Third
`Floor, Houston, Texas 77002 (US).
`
`gD
`
`Designated States (unless otherwise indicated, for every
`kind of national protection available): AE, AG, AL, AM,
`AO, AT, AU, AZ, BA, BB, BG, BH, BN, BR, BW, BY,
`BZ, CA, CH, CL, CN, CO, CR, CU, CZ, DE, DK, DM,
`DO, DZ, EC, EE, EG, ES, FI, GB, GD, GE, GH, GM, GT,
`HN, HR, HU, LD, LL, IN, IS, JP, KE, KG, KM, KN, KP,
`KR, KZ, LA, LC, LK, LR, LS, LT, LU, LY, MA, MD,
`ME, MG, MK, MN, MW, MX, MY, MZ, NA, NG, NI,
`NO, NZ, OM,PA, PE, PG, PH, PL, PT, QA, RO, RS, RU,
`RW, SC, SD, SE, SG, SK, SL, SM, ST, SV, SY, TH, TJ,
`TM, TN, TR, TT, TZ, UA, UG, US, UZ, VC, VN, ZA,
`ZM, ZW.
`
`(84)
`
`Designated States (unless otherwise indicated, for every
`kind of regional protection availabie}): ARIPO (BW, GH,
`GM, KE, LR, LS, MW, MZ, NA, RW, SD, SL, SZ, TZ,
`UG, ZM, ZW), Eurasian (AM, AZ, BY, KG, KZ, RU, TJ,
`TM), European (AL, AT, BE, BG, CH, CY, CZ, DE, DK,
`FE, ES, FL FR, GB, GR, HR, HU, IE, IS, IT, LT, LU, LV,
`MC, MK, MT, NL, NO, PL, PT, RO, RS, SF, ST, SK, SM,
`TR), OAPI (BF, BJ, CF, CG, CI CM, GA, GN, GQ, GW,
`ML, MR, NE, SN, TD, TG).
`Published:
`
`with international search report (Art. 21(3))
`
`(34) Title: MULTIPLE TOUCH SENSING MODES
`
`
`
`
`Touch
`Controller
`
`314
`
`302
`
`f 300
`
`306
`
`308
`
`310
`
`FIG. 3
`
`(57) Abstract: A touch controller of a computing device can adjust various modes ofoperation ofa touch panel in order to conserve
`resources on the device. The touch controller can dynamically adjust a rate at which touch sensors are scanned, or can scan touch
`sensors for the display panel using a different mode than for a single input button or other such element. The touch controller can
`also operate in a low power mode while the device is in standby, and thenactivate a high power mode of operation upon detecting
`an input such as a double tap. The touch controller can also alternate between lowand high power modes of operation basedatleast
`in part upon acurrent application executing on the device.
`
`AMZNO0001081
`
`
`
`wo2013/155098A1/IfMIMIINIMIINTANUTEITAMATA
`
`

`

`WO 2013/135098
`
`PCT/US2013/033824
`
`MULTIPLE TOUCH SENSING MODES
`
`CLAIMOF PRIORITY
`
`[0001]
`
`This patent application claims priority to U.S. Provisional Patent Application
`
`No. 61/621,809 filed on April 9, 2012, entitled “HYBRID TOUCH SENSING
`
`MODES?”whichis incorporated by reference herein in its entirety.
`
`BACKGROUND
`
`[0002]
`
`People are increasingly relying on computing devices, such as tablets and
`
`smart phones, which utilize touch sensitive displays. These displays enable users to
`
`enter text, select displayed items, or otherwise interact with the device by touching and
`
`performing various actions with respect to the display screen, as opposed to other
`
`conventional input methods. Devices are increasingly offering touch screens that can
`
`detect multiple touches, such as where a user uses more than two fingers to provide
`
`concurrent input. Such approaches typically consume a significant amount of power
`
`which is limited due to the battery capabilities of the device.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`[0003 |
`
`Various embodiments in accordance with the present disclosure will be
`
`described with reference to the drawings, in which:
`
`[0004]
`
`FIG.
`
`1
`
`illustrates an example of a user providing a single touch input to a
`
`device in accordance with various embodiments.
`
`[6005]
`
`FIG, 2 illustrates an example of a user providing a multi-touch input to a
`
`device in accordance with various embodiments.
`
`[0006]
`
`FIG, 3 illustrates an example cross-section of a sensor atray on a display
`
`element that can be utilized in accordance with various embodiments;
`
`AMZN0001082
`
`

`

`WO 2013/135098
`
`PCT/US2013/0335824
`
`
`
`[0007] FIG.4illustrates an example of a portable computing device utilizing a grid of
`
`sensor lines that can be used to detect objects coming in contact with the touch screcn
`
`display, in accordance with various embodiments;
`
`[0008]
`
`FIG. 5 illustrates an example of a mutual capacitance screen being used in a
`
`proximity detection mode that is used to sense objects in proximity to the touch screen
`
`display, in accordance with various embodiments;
`
`(0009]
`
`FIG 6 illustrates an example ofa self-capacitance screen being used in a proximity
`
`detection mode that is used to sense objects in proximity to the touch screen, in accordance
`
`with various embodiments;
`
`(0010]
`
`FIG. 7 illustrates an alternative example of a self-capacitance screen being used in
`
`proximity detection mode to sense objects in proximity to the touch screen, in accordance
`
`with various embodiments;
`
`(0011]
`
`FIG. 8 illustrates an example of a process for operating a touch controller in
`
`multiple modes of detection, in accordance with various embodiments;
`
`{0012]
`
` T'lG. 9A illustrates an example of a process for adjusting a scan rate of a touch
`
`controller in accordance with various embodiments;
`
`{0013}
`
`FIG. 9B illustrates an example of a process that can be used to operate the touch
`
`controller in a numberof different sub-modes, in accordance with various embodiments;
`
`
`
`{0014]—FIG. 10 illustrates front and back views of an example portable computing device
`
`that can be used in accordance with various embodiments;
`
`[0015]
`
`FIG. 11 illustrates an example set of basic components of a portable computing
`
`device, such as the device described with respect to FIG. 10; and
`
`[0016]
`
`FIG. 12 illustrates an example of an environment for implementing aspects in
`
`accordance with various embodiments.
`
`DETAILED DESCRIPTION
`
`[0017]
`
`In the following description, various embodiments will beillustrated by way of
`
`example and not by way of limitation in the figures of the accompanying drawings.
`
`References to various embodiments in this disclosure are not necessarily to the same
`
`2
`
`SUBSTITUTE SHEET (RULE 26)
`
`AMZN0001083
`
`

`

`WO 2013/135098
`
`PCT/US82013/033824
`
`References to various embodiments in this disclosure are not necessarily to the same
`
`embodiment, and such references mean at least one. While specific implementations
`
`and other details are discussed, it is to be understood that this is done for illustrative
`
`purposes only. A person skilled in the relevant art will recognize that other components
`
`and configurations may be used without departing from the scope and spirit of the
`
`claimed subject matter.
`
`[0018]
`
`Systems and methods in accordance with various embodiments of the
`
`present disclosure may overcome one or more of the aforementioned and other
`
`deficiencies experienced in conventional approaches
`
`to providing imput
`
`to, or
`
`determining information for, a computing device.
`
`In particular, various approaches
`
`discussed herein enable a touch sensitive display or other such element to operate in
`
`different modes at different times, in order to attempt to conserve power during time
`
`periods when certain functionality is not needed.
`
`In addition, various approaches
`
`described herein use a number of electric field and capacity sensing techniques that
`
`enable the computing device to detect objects (e.g., a human finger) coming within
`
`proximity of the touch sensitive display before the objects make any physical contact
`
`with the computing device.
`
`[0019]
`
`Tn accordance with an embodiment, a computing device (c.g., mobile phone,
`
`electronic reader or tablet computer) is described that includes a touch screen display
`
`and input assembly capable of detecting objects (e.g., human finger) in proximity of the
`
`touch screen or in physical contact with the touch screen. The touch screen includes a
`
`sensor layer (or several sensor layers) configured to detect changes in capacitance or
`
`changes in electric field caused by the objects in proximity of the display screen. The
`
`device further includes a touch controller, such as a low power microcontroller
`
`dedicated to sensing touches and/or objects. The touch controller is configured to
`
`analyze the changes in capacitance and/or electric field in order to detect the presence
`
`and location of objects in proximity ofthe display screen.
`
`[0020]
`
`In accordance with an embodiment,
`
`the touch controller is capable of
`
`operating in at least two modes of operation. The first mode, an “active” or “high-
`
`power” mode, can utilize mutual capacitive touch sensing that enables tracking of
`
`multiple finger touches and gestures. The second mode, an “idle” or “low-power” mode
`
`can instead utilize self-capacitance touch sensing. This low-power mode canbe utilized
`
`AMZNO0001084
`
`

`

`WO 2013/135098
`
`PCT/US82013/033824
`
`when single touch input will likely be utilized, and in some cases, can be used to bring
`
`the device back from a standby or similar mode into a high power mode where mutual
`
`capacitive sensing is used, in order to allow for multi-touch input. For example, when
`
`the computing device is in in the “idle” mode, the touch controller can operate in self-
`
`capacitance mode to save on battery power.
`
`If the touch controller detects a specified
`
`event or interaction of objects with the display screen (e.g., a user double tapping the
`
`display screen), the device can switch to begin scanning in “high-powered” mutual
`
`capacitance mode, where multi-touch events are more accurately detected. The self-
`
`capacitance mode and the mutual capacitance mode will be described in further detail
`
`later in this disclosure.
`
`[0021]
`
`In accordance with some embodiments,
`
`the touch controller is
`
`further
`
`capable of adjusting the scan rate used to scan the sensors of the display screen. For
`
`example, when the device is in the low-power or idle mode, or when the device is
`
`executing applications that are not capable of using multi-touch input,
`
`the touch
`
`controller may reduce the scan rate of the sensors in order to reduce power usage of the
`
`device. Similarly, when the device is awakened or when the application executing on
`
`the device is capable of utilizing multi-touch sensing, the scan rate can be increased to
`
`improve the accuracy of detecting multiple touch events. The adjusting of scan rates
`
`can be performed in the context of both the mutual capacitance mode and the self-
`
`capacitance mode of operation.
`
`[0022]
`
`In accordance with some embodiments, the touch screen further provides a
`
`“proximity detection” or “hover detection” mode that is capable of sensing objects that
`
`are in the proximity of the display screen but which have not made physical contact with
`
`any part of the display screen. A number of different approaches are described herein
`
`for enabling the proximity detection mode, in the context of both mutual capacitance
`
`mode of operation and self-capacitance mode of operation.
`
`[6023]
`
`FIG.
`
`1
`
`illustrates an example situation 100 wherein a user is holding a
`
`portable computing device 102 in the user’s hand 104. The computing device 102 can
`
`be any appropriate device, such as a smart phone, tablet computer, or personal data
`
`assistant, among other such options. The computing device 102 has a capacitive touch
`
`screen 106 that can detect when a portion of a user’s hand 104, such as a tip of a user’s
`
`finger or thumb, comes in contact with the touch screen (or at least within a detectable
`
`AMZNO0001085
`
`

`

`WO 2013/135098
`
`PCT/US82013/033824
`
`distance of the screen).
`
`In this example, the user is providing input with only the user’s
`
`thumb, such that an approach capable of determining a single input can be utilized.
`
`In
`
`some cases, however, the user might want to use multiple concurrent inputs to the touch
`
`screen. For example, FIG. 2 illustrates a situation where a user is holding a device 202
`
`(the sameor a different device from FIG. 1) with two hands 204 and concurrently using
`
`thumbs on both hands to enter text to the device through the touch screen. Many other
`
`such multi-touch input approaches can be used as well, such as a user using all ten
`
`fingers, a combination of fingers and objects, or other such input variations. By way of
`
`example, some applications allow the user to utilize “pinching” (or other multi-touch
`
`gestures) using two or more fingers to adjust the size of various objects displayed on the
`
`touch screen.
`
`In order to allow for such variance, a touch screen in accordance with
`
`various embodiments should be able to support multiple concurrent inputs.
`
`[0024]
`
`Touch screens can utilize a numberof different approaches to enabling touch
`
`input, including but not limited to resistive or capacitive touch based technology. As
`
`known in the art, a capacitive touch screen can be a self-capacitance or a mutual-
`
`capacitance screen, among other such options. A self-capacitance screen typically
`
`includes a layer of capacitive material, where in some embodiments, capacitors or
`
`capacitive regions are arranged in the layer according to a coordinate system. For
`
`example, a plurality of sensor lines can be arranged in a grid having multiple rows and
`
`columns(or other formation), where each sensor line is treated as a conductor that has a
`
`certain amount of capacitance. When an object (e.g.,human finger) comes in proximity
`
`or contact with the conductor, the object causes a change in capacitance of the sensor
`
`line(s). This capacitive change caused by the object can be measured in the various
`
`rows and columns using a current meter (or other such component), enabling the
`
`location of the touch to be determined (e.g., by determining the intersection of the
`
`affected sensor lines in the grid).
`
`Such an approach has relatively low power
`
`requirements and produces a relatively strong signal, but
`
`in some cascs cannot
`
`accurately resolve multiple touch locations, especially when more than one or two
`
`objects are simultaneously making contact with the screen. This can result in inaccurate
`
`touch location determinations or ghosting, among other such issues.
`
`[0025]
`
`In various embodiments, a mutual capacitance based approach can utilize the
`
`same set of sensor lincs or a different sct of sensor lines that arc configured to act as
`
`transmitters and receivers.
`
`For example, cach column of the sensor grid can be
`
`AMZNO0001086
`
`

`

`WO 2013/135098
`
`PCT/US82013/033824
`
`configured as a transmitter that transmits an electrical signal (c.g., produces an electric
`
`field) and each rowof the sensor grid can be configured as a receiver that receives that
`
`electrical signal. When an object such as a finger comes into proximity with the screen,
`
`the object causes a change in the amount of signal that the receiver is recerving. For
`
`example, the finger touching the screen can reduce the amount of signal being received
`
`by the receiver. Based on this change in signal,
`
`the location of the touch can be
`
`determined.
`
`In addition, multiple touches (e.g., 3 or more simultaneous touches) can be
`
`accurately located on the touch screen by using mutual capacitance. Thus, while mutual
`
`capacitance tends to be more accurate than self-capacitance, mutual capacitance also
`
`typically uses more power than self-capacitance (e.g., for transmitting/receiving the
`
`electrical signal).
`
`[0026]
`
`FIG. 3 illustrates an example cross-section of an arrangement 300 wherein
`
`touch sensors are placed on a display element 314, such as an LCD or OLEDdisplay, in
`
`order to provide a touch-sensitive display. A top, anti-reflective coating layer 302 is
`
`positioned over a protective cover element 304 in this example, which in some
`
`embodiments can be attached to the sensor layers using a bonding 306 layer of an
`
`appropriate adhesive material. A first touch sensor layer 308 is provided, which can
`
`include a grid of sensor lines, diamond pattern sensor lines, a set of parallel transparent
`
`touch sensors (running orthogonal
`
`to the plane of the figure), or another such
`
`configuration. The first sensor layer can be positioned on a layer of material 310, such
`
`as a thin film separator, that separates the first touch sensor layer from a second
`
`transparent
`
`touch sensor layer 312.
`
`The second touch sensor layer can have a
`
`corresponding set of grid, diamond, or parallel lime (running parallel! to the plane of the
`
`figure) pattern. As should be understood, various other arrangements and components
`
`can be used as well within the scope of the various embodiments, and in some
`
`embodiments, the sensor layers may be provided using one or more additional layers as
`
`well.
`
`[0027]
`
`in this example, a touch controller 316 is in electrical communication with
`
`the touch sensor layers 308, 310. The touch controller can cause a driving voltage to be
`
`applied to one of the layers, such as the first layer 308. A user bringing afinger close
`
`to, or in contact with, the top layer 302 can cause a changein the local electrostatic ficld
`
`around the arca of the touch, thus reducing the mutual capacitance at the capacitors at or
`
`near the area of the touch. The capacitance change at each capacitor point can be
`
`AMZNO0001087
`
`

`

`WO 2013/135098
`
`PCT/US82013/033824
`
`determined by measuring the voltage on the second touch sensor layer 312, or the
`
`sensing pattern. The touch controller can determine the appropriate input information,
`
`including information such as number,
`
`location, approximate size, and duration of a
`
`touch, and can provide that information to an application executing on at least one main
`
`processor of the device. Mutual capacitance can enable accurate multi-touch operation,
`
`such that a user can provide concurrent input using multiple fingers or objects, but such
`
`an approach frequently draws
`
`significantly more power
`
`than a selfcapacitance
`
`approach.
`
`[0028]
`
`Approaches in accordance with various embodiments can support multiple
`
`operational modes that provide multi-touch functionality as needed, but conserve power
`
`in other situations.
`
`In at least some embodiments, two modes of operation are provided
`
`for use with a touch controller. A first mode, an “active” or “high-power” mode, can
`
`utilize mutual capacitive touch sensing that enables tracking 10-finger touches and
`
`gestures. A second mode, an “idle” or “low-power” mode can instead utilize self-
`
`capacitance touch sensing, or operate at a lower frame rate. A low-power mode can be
`
`utilized when single touch input will likely be utilized, and in some cases can be used to
`
`bring the device back from a standby or similar mode into a high power mode where
`
`mutual capacitive sensing is used, in order to allow for multi-touch input.
`
`[0029]
`
`In various embodiments, a low power mode can be used when a device is in
`
`a standby, “sleep”, or other such state where the display and other device components
`
`may be inactive or in a low powerstate. A user, manufacturer, developer, or other such
`
`entity can define an input interaction to use with the touch screen which would be used
`
`to wake the device. For example, a double tap using a single finger can be detected by
`
`the device when in a low power mode, which can then cause the device to enter a high
`
`power mode.
`
`The touch controller can remain active in the low power mode,
`
`periodically scanning the touch panel for a double-tap event using self-capacitance. The
`
`event can be defined by several potential parameters, such as may include the touchsize
`
`of each tap, the time difference between the first and a second tap, and the location of
`
`each tap, among other such aspects. Upper and lower limits can be set for all
`
`parameters in order to reject false events and accept true double tap events. When the
`
`controller determines, based on a sct of well-defined logic operations, for cxamplc, that
`
`a double-tap event has occurred, the touch controller can send an interrupt signal (or
`
`other such trigger) to the host application processor, such that the device can go into a
`
`~
`
`AMZNO0001088
`
`

`

`WO 2013/135098
`
`PCT/US82013/033824
`
`high-power, mutual-capacitive sensing state.
`
`In some embodiments,the interaction that
`
`causes the controller to switch between the modes can be user configurable. For
`
`example, the user can select between multiple different events that cause the device to
`
`switch between modes or the user can be able to adjust the parameters of the double tap
`
`event, such as to adjust the speed or duration for which a double tap is recognized. For
`
`example, a range of times can be defined, such as with a lower limit on the order of
`
`about 100ms and an upper limit on the order of about 0.5 seconds. Further, the double
`
`tap location can be limited to a portion of the display panel, in order to reduce the area
`
`that must be scanned and further reduce power requirements.
`
`In order to prevent false
`
`input, the device can also analyze the size of the tap. For example, the area of contact
`
`detected for a user’s fingertip will be within a certain size range, such as from about
`
`5mm to about 10 mm. Touches with sizes outside this range might be rejected at least
`
`for purposes of waking the device, such as where the device is in a purse or backpack
`
`and might occasionally have something come into contact with the touch screen that
`
`affects the capacitance, but is not the size of a humanfingertip.
`
`[0030]
`
`In various alternative embodiments, other input actions can be defined to be
`
`used with the touch screen in order to wake the device. For example, a double tap with
`
`two fingers can be defined which can be detected using self-capacitance.
`
`In this
`
`example, the computing device can distinguish that the double tap was caused by two
`
`objects
`
`(e.g.,
`
`fingers)
`
`touching
`
`the
`
`screen
`
`simultaneously
`
`(or
`
`substantially
`
`simultaneously). Using this approach may require more complex detection algorithms,
`
`however, it may further decrease the likelihood that objects other than the user’s finger
`
`(e.g., accidentally touching the thigh of the user) would wake the device.
`
`In various
`
`embodiments, a number of other actions can be defined to place the device into “active”
`
`mode, including but not limited to a user drawing a plus sign or an “X”, dragging finger
`
`fromleft-to-right or top-to-bottom andthe like.
`
`In some embodiments, the user enabled
`
`to sclect one of the plurality of events or intcractions that cause the device to switch
`
`between the self-capacitance and mutual capacitance modeof opcration.
`
`[0031]
`
`In some embodiments,
`
`the touch controller can be configured,
`
`through
`
`firmware or otherwise, to enable the touch panel to operate in a dual mode supporting
`
`both sclf-capacitance and mutual-capacitance modes.
`
`In such a mode,
`
`the touch
`
`controller can first scan the touch pancl at a high frame rate to maintain an acceptable
`
`user experience, then can switch to a self-capacitance mode for a fast scan of one or
`
`AMZNO0001089
`
`

`

`WO 2013/135098
`
`PCT/US82013/033824
`
`more self-capacitance sensors that may be used as buttons (e.g., home button) or sliders
`
`on the device but outside the area of the display. These “soft” buttons are common on
`
`certam conventional devices, but scanning those single input buttons with a mutual
`
`capacitance process may waste poweron the device. A single touch sensor(or pair of
`
`touch sensors) might be used for each soft button, which does not actually have any
`
`mechanical moving parts and functions more like a touch “point.” The controller thus
`
`can alternate between a mutual-capacitance mode used to support multiple touches on
`
`the display panel, and a self-capacitance mode used to support
`
`the single touch
`
`operation of one or more soft buttons on the device.
`
`In some embodiments, when
`
`scanning, the touch panel and the soft button are scanned in a time period that is shorter
`
`than the refresh rate of the screen, which can result in a scan period of less than around
`
`l6ms for some devices. An acceptable signal to noise ratio also be maintained, as a
`
`high speed scan may introduce noise when not as much time is spent determining input
`
`at each location.
`
`[0032]
`
`In other embodiments, the device can selectively switch between mutual and
`
`self-capacitance modes for the touch panel. For example, certain applications, such as
`
`Solitaire, require only one or two finger operation while the device is active. The
`
`operating system can identify these applications to the host, such as by receiving
`
`instructions from the application. When these types of applications are running, the
`
`touch controller can operate in the low-power, self-capacitance mode where the touch
`
`controller can detect one or two simultaneous touches on the screen. For this operation,
`
`the touch panel scanning method can be different from the scanning method used when
`
`the device has been wakened and placed into active scanning mode. A device thus can
`
`operate in self capacitance mode to conserve power when the active applicationis a type
`
`that has been indicated as not supporting or requiring multiple touch input. This mode
`
`can also be jomed with the dual scanning mode discussed above.
`
`[0033]
`
`In some embodiments, the device can effectively throttle the active mode of
`
`the touch controller. For example, the touch controler can support mutual capacitance
`
`touch sensing in a high power mode.
`
`In this high power mode, the host or the controller
`
`can monitor touch statistics, such as the muamber of touches over a period of time (e.g.,
`
`per millisccond) for a sliding windowin timc.
`
`If the controller detcrmines that the
`
`number of touches is lower than a certain fraction of the touch scan rate, the scan rate
`
`can be reduced to save power. Similarly, if the controller determines that the number of
`
`AMZNO0001090
`
`

`

`WO 2013/135098
`
`PCT/US82013/033824
`
`touches has once again risen above another threshold, the scan rate can be increased
`
`again to ensure that a potential multi-touch event
`
`is not missed.
`
`In various
`
`embodiments, the statistics monitored by the touch controller can include any data about
`
`the changes in the capacitance measured by the sensors which may be relevant to
`
`determining information about the user touching the display screen. For example, the
`
`touch statistics may be the number of touches(e.g., single touches, multi-touches, etc.)
`
`detected over a predetermined period of time, a running average of the touches, number
`
`of touches at particular time of day, touches according to a particular application being
`
`executed, information about the relationship between multi-touches and single touches,
`
`and the like.
`
`[0034]
`
`In accordance with an embodiment, the throttling mode can also be enabled
`
`through knowledge of which application is running on the device. For example, if the
`
`user is watching a video, the likelihood of a multiple touch event may be substantially
`
`reduced and the controller can reduce the touch scan rate accordingly. Once the video is
`
`over or the user has initiated another application, the controller can once again increase
`
`the scan rate. By adjusting the scan rate in this manner, the touch controller is able to
`
`save on battery power of the device.
`
`[0035]
`
`In accordance with an cmbodiment, when in throttling mode,
`
`the touch
`
`controller can continually scan for touches, movement, accelerations of touches, or
`
`other such events, at a slower rate than the rate used in active mode. For example, as
`
`the rate of touches decreases, the device can slowly decrease the rate at which the touch
`
`controller scans the touch sensors. As the touch frequency increases, the controller can
`
`increase the scan rate, either gradually or directly back to the fastest scan rate in order to
`
`ensure that no touch information is missed. Similarly, if a user opens an application that
`
`generally uses multiple touch input, the scan rate can be increased accordingly. The
`
`operating system in such an instance can pass information about the application to the
`
`host processor, an application processor, or another such component, which can provide
`
`the touch controller with information about the type of input needed for that application.
`
`The use of dynamic scan throttling can help minimize the amount of power used for a
`
`mutual capacitance mode, or even a self capacitance mode in some embodiments. The
`
`throttling decisions in some cmbodiments thus can be a combination of touch
`
`information coming from the touch screen and application-specific mformation coming
`
`from the operating system.
`
`10
`
`AMZNO0001091
`
`

`

`WO 2013/135098
`
`PCT/US82013/033824
`
`(0036)
`
`In some embodiments, a device in throttling mode can periodically perform a
`
`quick scan over a period of time in order to ensure that touches are not being missed.
`
`For example, the controller may throttle the scan speed downto 10% of the maximum
`
`rate, and after a determined period of time has lapsed, increase the rate back up to the
`
`full rate, even if no increase in touch frequency has been detected. This may decrease
`
`the likelihood of missing multi-touch events while still obtaining some powersavings.
`
`[0037]
`
`FIG, 4 illustrates an example of a portable computing device 401 utilizing a
`
`grid of sensor lines that can be used to detect objects coming in contact with the touch
`
`screen display, in accordance with various embodiments.
`
`In the illustrated embodiment,
`
`the sensor lines are arranged in a grid formation 402 that inclides a number of rows 404
`
`and a number of columns 403. The grid can cover substantially the entire touch screen
`
`or display screen of the mobile computing device 401.
`
`[0038]
`
`In accordance with an embodiment, when operating in the mutual
`
`capacitance mode, the columns 403 of the grid can be configured to be transmitters that
`
`transmit an electronic signal (e.g., emit an electric field) and the rows 404 can be
`
`configured as receivers that receive the electronic signal. When an object, such as a
`
`finger, is present on the screen, the object reduces the amount of signal that the receiver
`
`is recciving. Based on such reduced signal being detected the touch controller can
`
`determine the location of the object on the screen at the intersection of the transmitter
`
`and receiver. Mutual capacitance thus enables the controller to determine the locations
`
`of multiple touches based on changes in capacitance at each intersection.
`
`[0039]
`
`When operating in self-capacitance mode,
`
`there are no transmitters or
`
`receivers.
`
`Instead, each sensorline is treated as a conductive metal plate.
`
`In this mode,
`
`the touch controller is capable of measuring the base self-capacitance of each sensor
`
`line. When an object, such as a finger, touches one or more of the sensor lines (or
`
`comes into close proximity with the sensor lines), the capacitance of the object gets
`
`added to the capacitance of the sensor line.
`
`The line thus sees an increase in
`
`capacitance, which is detected by the touch controller. Based on the intersection of the
`
`lines which have seen an increase in capacitance,
`
`the touch controller is able to
`
`determine the location of the object on the screen. Thus, in self-capacitance mode, the
`
`controller scans each individual sensor line for changes in capacitance, in contrast to
`
`li
`
`AMZNO0001092
`
`

`

`WO 2013/135098
`
`PCT/US82013/033824
`
`scanning for changes in capacitance at each intersection between two sensor lines when
`
`operating in mutual capacitance mode.
`
`[0040]
`
`It should be noted that in various embodiments, the plurality of sensors of
`
`the touch screen display can be contained in a single sensor layer or can be distributed
`
`between multiple sensor layers. For example, in some embodiments, the sensor rows
`
`may be contained in one layer, while the sensor columns are contained in a separate
`
`sensor layer.
`
`In other embodiments, both rows and columns are contained in the same
`
`layer.
`
`[0041]
`
`FIG. 5 illustrates an example of a mutual capacitance screen being used in a
`
`proximity detection mode that is used to sense objects in proximity to the touch screen
`
`display, in accordance with various embodiments.
`
`In the illustrated embodiment, some
`
`of the rows that would normally be a recetver are converted to be transmitters. For
`
`example, the row at the top of the screen 503 can be