Patent Publication Number: US-2021191564-A1

Title: Single-layer capacitive image sensor

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is a continuation of U.S. application Ser. No. 16/580,531 filed Sep. 24, 2019, entitled “SINGLE-LAYER CAPACITIVE IMAGE SENSOR,” which claims priority and benefit under 35 USC § 119(e) to U.S. Provisional Patent Application No. 62/741,485, filed on Oct. 4, 2018, the entireties of which are incorporated by reference herein. 
    
    
     TECHNICAL FIELD 
     The present embodiments relate generally to capacitive sensing, and specifically to measuring a resistance between sensor electrodes. 
     BACKGROUND OF RELATED ART 
     Input devices including proximity sensor devices are widely used in a variety of electronic systems. A proximity sensor device may include a sensing region, often demarked by an input surface, in which the proximity sensor device determines the presence, location, force, and/or motion of one or more input objects. Proximity sensor devices may be used to provide interfaces for the electronic system. For example, proximity sensor devices may be used as input devices for larger computing systems (such as opaque touchpads integrated in, or peripheral to, notebook or desktop computers). Proximity sensor devices may also be used in smaller computing systems, such as touch screens integrated in cellular phones. 
     Proximity sensors may operate by detecting changes in an electric field and/or capacitance in the sensing region. For example, the sensing region may include a number of conductors that can be configured to transmit and/or receive an electric signal. The signal can then be used to measure a capacitive coupling between various pairs of conductors. A “baseline” represents the expected capacitance for a pair of conductors when no external objects are present in the sensing region. Objects in contact with (or close proximity to) the sensing region may alter the effective capacitance of the conductors (e.g., from the baseline). Thus, a detected change in capacitance across one or more pairs of conductors may signal the presence and/or position of an object in the sensing region. 
     SUMMARY 
     This Summary is provided to introduce in a simplified form a selection of concepts that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claims subject matter, nor is it intended to limit the scope of the claimed subject matter. 
     An array of sensor electrodes is disclosed with localized groups of transmitter electrodes and reused receiver channels in each row. One innovative aspect of the subject matter of this disclosure can be implemented in a capacitive sensing array including a first transmitter electrode, a plurality of first receiver electrodes, a second transmitter electrode, and a plurality of second receiver electrodes disposed in a first row of the capacitive sensor array. The first transmitter electrode is disposed in a first column of the capacitive sensor array and is coupled to a first transmitter channel. The first receiver electrodes are disposed in a second column of the capacitive sensor array, adjacent the first transmitter electrode, and are coupled to a respective one of a plurality of first receiver channels. The second transmitter electrode is disposed in a third column of the capacitive sensor array and is coupled to a second transmitter channel. The second receiver electrodes are disposed in a fourth column of the capacitive sensor array, adjacent the second transmitter electrode, and are coupled to a respective one of the first receiver channels. 
     Another innovative aspect of the subject matter of this disclosure can be implemented in a method of capacitive sensing. The method may include steps of activating a first transmitter channel coupled to a first transmitter electrode, where the first transmitter electrode is disposed in a first row and a first column of a capacitive sensing array; sensing a capacitive coupling between the first transmitter electrode and a plurality of first receiver electrodes adjacent the first transmitter electrode when the first transmitter channel is activated, where the first receiver electrodes are disposed in the first row and a second column of the capacitive sensor array; activating a second transmitter channel coupled to a second transmitter electrode, where the second transmitter electrode is disposed in the first row and a third column of the capacitive sensor array; and sensing a capacitive coupling between the second transmitter electrode and a plurality of second receiver electrodes adjacent the second transmitter electrode when the second transmitter channel is activated, where the second receiver electrodes are disposed in the first row and a fourth column of the capacitive sensor array. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present embodiments are illustrated by way of example and are not intended to be limited by the figures of the accompanying drawings. 
         FIG. 1  shows an example input device within which the present embodiments may be implemented. 
         FIGS. 2A-2C  show an input device having sensor electrodes disposed on a single layer, in accordance with some embodiments. 
         FIG. 3  shows a single-layer sensor electrode configuration, in accordance with some embodiments. 
         FIG. 4  shows a single-layer sensor electrode configuration including two sets of sensor electrode arrays, in accordance with some embodiments. 
         FIG. 5  shows a single-layer sensor electrode configuration including four sets of sensor electrode arrays, in accordance with some embodiments. 
         FIGS. 6A and 6B  show single-layer sensor electrode configurations including four sets of sensor electrode arrays, in accordance with some other embodiments. 
         FIG. 7  shows an example sensor configuration of a sensing region, in accordance with some embodiments. 
         FIG. 8  shows another example sensor configuration of a sensing region, in accordance with some embodiments. 
         FIG. 9  shows a single-layer capacitive sensing array, in accordance with some other embodiments. 
         FIG. 10  shows a single-layer capacitive sensing array with a unique mapping of transmit and receive channels, in accordance with some embodiments. 
         FIG. 11  shows a single-layer capacitive sensing array with balanced capacitive background coupling, in accordance with some embodiments. 
         FIG. 12  shows a single-layer capacitive sensing array with relatively balanced capacitive background coupling, in accordance with some embodiments. 
         FIG. 13  is an illustrative flowchart depicting an example capacitive sensing operation, in accordance with some embodiments. 
     
    
    
     DETAILED DESCRIPTION 
     In the following description, numerous specific details are set forth such as examples of specific components, circuits, and processes to provide a thorough understanding of the present disclosure. The term “coupled” as used herein means connected directly to or connected through one or more intervening components or circuits. Also, in the following description and for purposes of explanation, specific nomenclature is set forth to provide a thorough understanding of the aspects of the disclosure. However, it will be apparent to one skilled in the art that these specific details may not be required to practice the example embodiments. In other instances, well-known circuits and devices are shown in block diagram form to avoid obscuring the present disclosure. Some portions of the detailed descriptions which follow are presented in terms of procedures, logic blocks, processing and other symbolic representations of operations on data bits within a computer memory. The interconnection between circuit elements or software blocks may be shown as buses or as single signal lines. Each of the buses may alternatively be a single signal line, and each of the single signal lines may alternatively be buses, and a single line or bus may represent any one or more of a myriad of physical or logical mechanisms for communication between components. 
     Unless specifically stated otherwise as apparent from the following discussions, it is appreciated that throughout the present application, discussions utilizing the terms such as “accessing,” “receiving,” “sending,” “using,” “selecting,” “determining,” “normalizing,” “multiplying,” “averaging,” “monitoring,” “comparing,” “applying,” “updating,” “measuring,” “deriving” or the like, refer to the actions and processes of a computer system, or similar electronic computing device, that manipulates and transforms data represented as physical (electronic) quantities within the computer system&#39;s registers and memories into other data similarly represented as physical quantities within the computer system memories or registers or other such information storage, transmission or display devices. 
     The techniques described herein may be implemented in hardware, software, firmware, or any combination thereof, unless specifically described as being implemented in a specific manner. Any features described as modules or components may also be implemented together in an integrated logic device or separately as discrete but interoperable logic devices. If implemented in software, the techniques may be realized at least in part by a non-transitory computer-readable storage medium comprising instructions that, when executed, performs one or more of the methods described above. The non-transitory computer-readable storage medium may form part of a computer program product, which may include packaging materials. 
     The non-transitory processor-readable storage medium may comprise random access memory (RAM) such as synchronous dynamic random access memory (SDRAM), read only memory (ROM), non-volatile random access memory (NVRAM), electrically erasable programmable read-only memory (EEPROM), FLASH memory, other known storage media, and the like. The techniques additionally, or alternatively, may be realized at least in part by a processor-readable communication medium that carries or communicates code in the form of instructions or data structures and that can be accessed, read, and/or executed by a computer or other processor. 
     The various illustrative logical blocks, modules, circuits and instructions described in connection with the embodiments disclosed herein may be executed by one or more processors. The term “processor,” as used herein may refer to any general purpose processor, conventional processor, controller, microcontroller, special purpose processor, and/or state machine capable of executing scripts or instructions of one or more software programs stored in memory. 
       FIG. 1  shows an example input device  100  within which the present embodiments may be implemented. The input device  100  includes a processing system  110  and a sensing region  120 . The input device  100  may be configured to provide input to an electronic system  150 . Examples of electronic systems may include personal computing devices (e.g., desktop computers, laptop computers, netbook computers, tablets, web browsers, e-book readers, and personal digital assistants (PDAs)), composite input devices (e.g., physical keyboards, joysticks, and key switches), data input devices (e.g., remote controls and mice), data output devices (e.g., display screens and printers), remote terminals, kiosks, video game machines (e.g., video game consoles, portable gaming devices, and the like), communication devices (e.g., cellular phones such as smart phones), and media devices (e.g., recorders, editors, and players such as televisions, set-top boxes, music players, digital photo frames, and digital cameras). 
     In some aspects, the input device  100  may be implemented as a physical part of the corresponding electronic system  150 . Alternatively, the input device  100  may be physically separated from the electronic system  150 . The input device  100  may be coupled to (and communicate with) components of the electronic system  150  using various wired and/or wireless interconnection and communication technologies, such as buses and networks. Examples technologies may include Inter-Integrated Circuit (I 2 C), Serial Peripheral Interface (SPI), PS/2, Universal Serial bus (USB), Bluetooth®, Infrared Data Association (IrDA), and various radio frequency (RF) communication protocols defined by the IEEE 802.11 standard. 
     In the example of  FIG. 1 , the input device  100  may correspond to a proximity sensor device configured to sense input provided by one or more input objects  140  in the sensing region  120 . Example proximity sensor devices may include touchpads, touch screens, touch sensor devices, and the like. Example input objects  140  may include fingers, styli, and the like. The sensing region  120  may encompass any space above, around, in, and/or proximate to the input device  100  in which the input device  100  is able to detect user input, such as provided by one or more input objects  140 . The size, shape, and/or location of the sensing region  120 , relative to the electronic system  150 , may vary depending on actual implementations. 
     In some embodiments, the sensing region  120  may extend from a surface of the input device  100  in one or more directions in space, for example, until a signal-to-noise ratio (SNR) of the sensors falls below a threshold suitable for object detection. For example, the distance to which the sensing region  120  extends in a particular direction may be on the order of less than a millimeter, millimeters, centimeters, or more, and may vary with the type of sensing technology used and/or accuracy desired. In some embodiments, the sensing region  120  may detect inputs involving no physical contact with any surfaces of the input device  100 , contact with an input surface (e.g., a touch surface and/or screen) of the input device  100 , contact with an input surface of the input device  100  coupled with some amount of applied force or pressure, and/or any combination thereof. 
     In some embodiments, input surfaces may be provided by, and/or projected on, one or more surfaces of a housing of the input device  100  (e.g., as an image). For example, the sensing region  120  may have a rectangular shape when projected onto an input surface of the input device  100 . In some aspects, inputs may be provided through images spanning one, two, three, or higher dimensional spaces in the sensing region  120 . In some other aspects, inputs may be provided through projections along particular axes or planes in the sensing region  120 . Still further, in some aspects, inputs may be provided through a combination of images and projections in the sensing region  120 . 
     The input device  100  may utilize various sensing technologies to detect user input. Example sensing technologies may include capacitive, elastive, resistive, inductive, magnetic, acoustic, ultrasonic, and optical sensing technologies. In some embodiments, the input device  100  may utilize capacitive sensing technologies to detect user inputs. For example, the sensing region  120  may include one or more capacitive sensing elements  121  (e.g., sensor electrodes) to create an electric field. The input device  100  may detect inputs based on changes in capacitance of the sensing elements  121 . For example, an object in contact with (or close proximity to) the electric field may cause changes in the voltage and/or current in the sensing elements  121 . Such changes in voltage and/or current may be detected as “signals” indicative of user input. The sensing elements  121  may be arranged in arrays or other configurations to detect inputs at multiple points within the sensing region  120 . In some aspects, some sensing elements  121  may be ohmically shorted together to form larger sensor electrodes. Some capacitive sensing technologies may utilize resistive sheets that provide a uniform layer of resistance. 
     Example capacitive sensing technologies may be based on “self-capacitance” (also referred to as “absolute capacitance”) and/or “mutual capacitance” (also referred to as “transcapacitance”). Absolute capacitance sensing methods detect changes in the capacitive coupling between one or more of the sensing elements  121  and an input object. For example, an input object near one or more of the sensing elements  121  may alter the electric field near the sensing elements  121 , thus changing the measured capacitive coupling between two or more sensor electrodes of the sensing elements  121 . In some embodiments, the input device  100  may implement absolute capacitance sensing by modulating sensor electrodes with respect to a reference voltage and detecting the capacitive coupling between the sensor electrodes and input objects. The reference voltage may be substantially constant or may vary. In some aspects, the reference voltage may correspond to a ground potential. 
     Transcapacitance sensing methods detect changes in the capacitive coupling between sensor electrodes. The change in capacitive coupling may be between sensor electrodes in two different sensing elements  121  or between two different sensor electrodes in the same sensing element  121 . For example, an input object near the sensor electrodes may alter the electric field between the sensor electrodes, thus changing the measured capacitive coupling of the sensor electrodes. In some embodiments, the input device  100  may implement transcapacitance sensing by detecting the capacitive coupling between one or more “transmitter” sensor electrodes and one or more “receiver” sensor electrodes. Transmitter sensor electrodes may be modulated relative to the receiver sensor electrodes. For example, the transmitter sensor electrodes may be modulated relative to a reference voltage to transmit signals, while the receiver sensor electrodes may be held at a relatively constant voltage to “receive” the transmitted signals. The signals received by the receiver sensor electrodes may be affected by environmental interference (e.g., from other electromagnetic signals and/or objects in contact with, or in close proximity to, the sensor electrodes). In some aspects, each sensor electrode may either be a dedicated transmitter or a dedicated receiver. In other aspects, each sensor electrode may be configured to transmit and receive. 
     In some embodiments, the input device  100  may further detect a force exerted on an input surface coinciding with the sensing region  120 . For example, the input device  100  may include one or more force sensors configured to generate force information representative of the force exerted by the input object  140  when making contact with the sensing region  120 . In some aspects, the force information may be in the form of electrical signals representative of an amplitude (or change in amplitude) of the force applied to the input surface. For example, the force sensors may be formed, at least in part, by conductors provided on an underside of the input surface and a structure (such as a midframe) underlying the input surface. More specifically, the input surface may be configured to move (e.g., deflect and/or compress) relative to the underlying structure when a force is applied the input object  140 . The force sensors may produce electrical signals based on a change in capacitance, between the conductors, when the input surface moves relative to the underlying structure. 
     The processing system  110  may be configured to operate the hardware of the input device  100  to detect input in the sensing region  120 . In some embodiments, the processing system  110  may control one or more sensor electrodes and/or force sensors to detect objects in the sensing region  120 . For example, the processing system  110  may be configured to transmit signals via one or more transmitter sensor electrodes and receive signals via one or more receiver sensor electrodes. The processing system  110  may also be configured to receive force information via one or more force sensors. In some aspects, one or more components of the processing system  110  may be co-located, for example, in close proximity to the sensing elements of the input device  100 . In other aspects, one or more components of the processing system  110  may be physically separated from the sensing elements of the input device  100 . For example, the input device  100  may be a peripheral coupled to a computing device, and the processing system  110  may be implemented as software executed by a central processing unit (CPU) of the computing device. In another example, the input device  100  may be physically integrated in a mobile device, and the processing system  110  may correspond, at least in part, to a CPU of the mobile device. 
     In some embodiments, the processing system  110  may be implemented as a set of modules that are implemented in firmware, software, or a combination thereof. Example modules include hardware operation modules for operating hardware such as sensor electrodes and display screens; data processing modules for processing data such as sensor signals and positional information; and reporting modules for reporting information. In some embodiments, the processing system  110  may include sensor operation modules configured to operate sensing elements to detect user input in the sensing region  120 ; identification modules configured to identify gestures such as mode changing gestures; and mode changing modules for changing operation modes of the input device  100  and/or electronic system  150 . 
     The processing system  110  may respond to user input in the sensing region  120  by triggering one or more actions. Example actions include changing an operation mode of the input device  110  and/or graphical user interface (GUI) actions such as cursor movement, selection, menu navigation, and the like. In some embodiments, the processing system  110  may provide information about the detected input to the electronic system  150  (e.g., to a CPU of the electronic system). The electronic system  150  may then process information received from the processing system  110  to carry out additional actions (e.g., changing a mode of the electronic system and/or GUI actions). 
     The processing system  110  may operate the sensing elements of the input device  100  to produce electrical signals indicative of input (or lack of input) in the sensing region  120 . The processing system  110  may perform any appropriate amount of processing on the electrical signals to translate or generate the information provided to the electronic system  150 . For example, the processing system  110  may digitize analog signals received via the sensor electrodes and/or perform filtering or conditioning on the received signals. In some aspects, the processing system  110  may subtract or otherwise account for a “baseline” associated with the sensor electrodes. For example, the baseline may represent a state of the sensor electrodes when no user input is detected. In some embodiments, the processing system  110  may further determine positional information and/or force information for a detected input. The term “positional information,” as used herein, refers to any information describing or otherwise indicating a position or location of the detected input (e.g., within the sensing region  120 ). Example positional information may include absolute position, relative position, velocity, acceleration, and/or other types of spatial information. 
     In some embodiments, the input device  100  may include a touch screen interface (e.g., display screen) that at least partially overlaps the sensing region  120 . For example, the sensor electrodes of the input device  100  may form a substantially transparent overlay on the display screen, thereby providing a touch screen interface for the associated electronic system  150 . The display screen may be any type of dynamic display capable of displaying a visual interface to a user. Examples of suitable display screen technologies may include light emitting diode (LED), organic LED (OLED), cathode ray tube (CRT), liquid crystal display (LCD), plasma, electroluminescence (EL), or other display technology. 
     In some embodiments, the input device  100  may share physical elements with the display screen. For example, one or more of the sensor electrodes may be used in displaying the interface and sensing inputs. More specifically, a sensor electrode used for sensing inputs may also operate as a display electrode used for displaying at least a portion of the interface. In some embodiments, the input device  100  may include a first sensor electrode configured for displaying at least part of the interface and sensing inputs, and a second sensor electrode may be configured for input sensing only. For example, the second sensor electrode may be disposed between substrates of the display device or may be external to the display device. 
     In some aspects, the display screen may be controlled or operated, at least in part, by the processing system  110 . The processing system  110  may be configured to execute instructions related to sensing inputs and displaying the interface. For example, the processing system  110  may drive a display electrode to display at least a portion of the interface and sense user inputs, concurrently. In another example, the processing system  110  may drive a first display electrode to display at least a portion of the interface while concurrently driving a second display electrode to sense user inputs. 
     In some configuration, the sensing elements  121  may be coupled to the processing system  110  via a plurality of traces. A trace is an electronic component that connects an electrode region within a sensor electrode (e.g., sensing element  121 ) to the controlling electronics found in the proximity sensor device (e.g., the processing system  110 ). It is noted that the cost and size limitations placed on the input device  100  are often created by the number of traces, the number of connection points, the connection component&#39;s complexity (e.g., number of pins on a connector) and the complexity of the flexible components used to interconnect the sensing elements  121  to the processing system  110 . 
     During the operation of the input device  110 , the presence of an input object over the sensing region  120  will interfere with the signal provided by the driven sensing elements  121  (e.g., transmitter electrodes) and also their respective traces (e.g., transmitter traces). However, the coupling between the transmitter electrodes and the receiver electrodes is also affected by the interaction between the transmitter traces and the receiver electrodes. Thus, the interaction of an input object and the signal carried on the traces will cause an unwanted parasitic response. The parasitic response may cause the processing system  110  to incorrectly determine that one or more phantom input objects are interacting with the sensing region  120  (e.g., resulting in one or more ghost touches). Moreover, the greater the length of the traces used to interconnect the sensor electrodes to the computer system, the more susceptible the input device  100  is to interference, such as electromagnetic interference (EMI), and the more susceptible the input device  100  is to a parasitic response. The parasitic response and interference provided by these supporting components will adversely affect the reliability and accuracy of the data collected by the input device  100 . 
     Aspects of the present disclosure enable 2-D capacitance images to be created using a single sensing layer in which the transmitting and receiving sensor electrodes are coplanar with one another (e.g., without the use of jumpers within the sensing region  120 ). The reduced number of layers used to form the input device described herein versus other conventional position sensing devices also equates to fewer production steps, which will reduce the production cost of the device. The reduction in the layers of the input device also decreases interference or obscuration of an image or display that is viewed through the sensor, thus lending itself to improved optical quality of the formed input device when it is integrated with a display device. 
       FIG. 2A  shows an input device  295  having sensor electrodes disposed on a single layer, in accordance with some embodiments. One will note that the input device  295  may be formed as part of a larger input device  100 , which is discussed above. In general, the sensor electrode pattern disclosed herein comprises a sensor array  200  that includes a plurality of sensor electrode sub-arrays  210  that include a plurality of arrays of sensor electrodes that include a plurality of sensor electrodes, such as sensor electrodes  202  and  211 , that are arranged and interconnected in a desirable manner to reduce or minimize the number of traces and/or sensor electrodes required to sense the positional information of an input object within the sensing region  120  of the input device  295 . 
     While  FIG. 2A  illustrates a pattern of simple rectangles used to represent the sensor electrodes, this configuration is not meant to be limiting and in other embodiments, various other sensor electrode shapes may be used as discussed further herein. For example, in some embodiments, sensing elements  121  comprise two or more sensor electrodes, for example, sensor electrodes  202  and  211  that may be similar or different in size and/or shape. In general, a sensor electrode includes an electrode region, or portion of the sensor electrode that is intended to capacitively couple to another sensor electrode, and a trace. In one example the electrode region has a polygonal shape, such as electrode regions  203  or electrode region  204  illustrated in  FIG. 2C . 
     A trace, such as trace  212  or trace  213  in  FIG. 2A , is used to connect the electrode region to other electrode regions or other electronic components in the input device  295 . In one example, as shown, these sensor electrodes are disposed in a sensor electrode pattern that comprises a first plurality of sensor electrodes  202  (e.g., 15 shown) and a second plurality of sensor electrodes  211  (e.g., 30 shown), which are disposed on the same layer as the first plurality of sensor electrodes  202 . Sensor electrodes  202  and sensor electrodes  211  may be ohmically isolated from one another, by use of insulating materials or a physical gap formed between the electrodes to prevent them from electrically shorting to each other. 
     In some configurations, two or more sensing elements  121  may form a larger unit cell  122 . A unit cell  122  includes a grouping of sensor electrodes that are repeated within a sensor electrode sub-array  210  and/or in a repeating pattern across the sensing region  120  (e.g., multiple sensor electrode sub-arrays  210 ). The unit cell  122  is the smallest unit a symmetric grouping of sensor electrodes can be broken into within an electrode pattern formed across the sensing region  120 . As illustrated in  FIG. 2A , in one example, the unit cell  122  includes two sensing elements  121 , which each contain a portion of the sensor electrode  202  and the sensor electrode  211 , and thus the unit cell  122  comprises a sensor electrode  202  and two sensor electrodes  211 . 
     The sensor electrode pattern of  FIG. 2A  may utilize various sensing techniques, such as mutual capacitive sensing, absolute capacitive sensing, elastive, resistive, inductive, magnetic acoustic, ultrasonic, or other useful sensing techniques, without deviating from the scope of this disclosure. In some aspects, sensor electrode  202  maybe be a transmitter electrode and sensor electrode  211  may be a receiver electrode. In other aspects, sensor electrode  211  may be a transmitter electrode and sensor electrode  202  may be a receiver electrode. 
     In some embodiments, the sensing elements  121  may comprise a plurality of transmitter and receiver electrodes that are formed in a single layer on a surface of a substrate  209 . In one configuration of the input device  295 , each of the sensor electrodes may comprise one or more transmitter electrodes (e.g., sensor electrodes  202 ) that are disposed proximate to one or more receiver electrodes (e.g., sensor electrodes  211 ). For example, the input device  295  may operate by detecting the change in capacitive coupling between one or more of the driven transmitter sensor electrodes and one or more of the receiver electrodes, as similarly discussed above. In some aspects, the transmitter and receiver electrodes may be disposed in such a way such that jumpers and/or extra layers used to form the area of capacitive sensing pixels are not required. 
     In some implementations, the transmitter electrodes and receiver electrodes may be formed in an array on the surface of a substrate  209  by first forming a blanket conductive layer on the surface of the substrate  209  and then performing an etching and/or patterning process (e.g., lithography and wet etch, laser ablation, etc.) that ohmically isolates each of the transmitter electrodes and receiver electrodes from each other. In other implementations, the sensor electrodes may be patterned using deposition and screen printing methods. As illustrated in  FIG. 2A , these sensor electrodes may be disposed in an array that comprises a rectangular pattern of sensing elements  121 , which may comprise one or more transmitter electrodes and one or more receiver electrodes. For example, the blanket conductive layer used to form the transmitter electrodes and receiver electrodes may comprise a thin metal layer (e.g., copper, aluminum, etc.) or a thin transparent conductive oxide layer (e.g., ATO, ITO, Zinc oxide) that is deposited using convention deposition techniques known in the art (e.g., PVD, CVD). 
     In some aspects, patterned isolated conductive electrodes (e.g., electrically floating electrodes) may be used to improve visual appearance. For example, the sensor electrodes may be formed from a material that is substantially optically clear, and thus, in some configurations, can be disposed between a display device and the input device user. In some other configurations, a substantially transparent (e.g. less than 50% space filling) conductive metal mesh may be disposed between a display and the user. The conductive metal mesh may be configured to transmit a substantial fraction of each of the display&#39;s pixels which it covers, and may be patterned and aligned relative to the pixels and/or RGB sub-pixels such that viewing angle is not substantially affected (e.g., allowing 80 degree off-angle viewing without significant color shift or brightness loss). For example, a metal mesh with widths of less than 5 microns may be patterned on a thin film (e.g., less than 20 microns) encapsulation layer of an OLED display with a spacing away from each covered pixel such that a more than 35 degree angle from vertical light ray may pass from the display pixels to the user. 
     The areas of localized capacitive coupling formed between at least a portion of one or more sensor electrodes  202  and at least a portion of one or more sensor electrodes  211  may be termed a “capacitive pixel,” “capacitive sensing pixel” or also referred to herein as the sensing element  121 . For example, as shown in  FIG. 2A , the capacitive coupling in a sensing element  121  may be created by the electric field formed between at least a portion of the sensor electrodes  202  and a sensor electrode  211 , which changes as the proximity and motion of input objects across the sensing region changes. 
     In transcapacitive sensing implementations, since a driven transmitter electrode can capacitively couple with multiple receiver electrodes disposed within the sensing region  120 , the phrase “directly coupled to” or “directly capacitively coupled to” is used herein to help clarify the capacitive sensing elements that are intended to form a part of a sensing element  121 . For example, directly coupled sensor electrodes may include a transmitter electrode and a receiver electrode that is the transmitter electrode&#39;s nearest neighbor. One skilled in the art will appreciate that the capacitive coupling between nearest neighbors may be created by the electric fields formed at or near the edges of the nearest neighbor electrodes. 
     The phrase “adjacent sensor electrodes” is used herein to describe nearest neighbor sensor electrodes that are separated by a physical gap or have a minimal capacitive coupling affecting obstruction disposed between the adjacent electrodes. For example, the transmitter electrode  2021  in  FIG. 2A  can be said to be adjacent to receiver electrode  2111  since the sensor electrodes are separated only by a physical gap. In another example, the transmitter electrode  2022  can be said to be adjacent to receiver electrode  2112  even though a trace  213  is disposed between the electrodes because the size of the trace is significantly smaller than the useful electrode region of the sensor electrodes. It is noted that the measured change in capacitance created by the interaction of an input object  140  and the electric field lines created between the transmitter electrode  2022  and receiver electrode  2112  is primarily due to the interaction of the input object  140  and the electric field lines that pass through a region that is above the plane, or planes, that the electrodes reside in, such as above the surface of a lens disposed over a portion of the input device  100 . Therefore, the presence of the trace  213  between the transmitter electrode  2022  and receiver electrode  2112  may have a negligible effect on the measured change in capacitance detected by the processing system  110 . 
     The sensing elements  121  are “scanned” to detect the capacitive couplings between sensor electrodes. For example, the input device  295  may be operated such that one transmitter electrode transmits at one time, or multiple transmitter electrodes transmit at the same time. Where multiple transmitter electrodes transmit simultaneously, these multiple transmitter electrodes may transmit the same transmitter signal and effectively produce an effectively larger transmitter electrode, or these multiple transmitter electrodes may transmit different transmitter signals. In one example, the transmitter electrodes are the sensor electrodes  202  and the receiver electrodes are the sensor electrodes  211 . However, in actual implementations, any of the sensor electrodes described herein may perform the functions of a transmitter electrode and/or a receiver electrode. 
     In some aspects, multiple sensor electrodes  202  may transmit different transmitter signals according to one or more coding schemes that enable their combined effects on the resulting signals received by the receiving sensor electrodes, or sensor electrodes  211 , to be independently determined. Where the multiple transmitter electrodes simultaneously transmit different transmitter signals (e.g., different phase, amplitude, frequency), the transmissions may be encoded such that the resulting charge transfer is sufficiently orthogonal (e.g., transmissions are independent functions) such that they may be decoded. For example, a Unitary Hadamard matrix may be used for both coding and decoding. An input object in contact with (or proximity of) the sensing region may affect (e.g., reduce the fringing coupling) of the resulting signals. 
     The receiver electrodes, or a corresponding sensor electrode  211 , may be operated singly or multiply to acquire resulting signals created from the transmitter signal. The resulting signals may indicate the capacitive couplings at the capacitive pixels, which are used to determine whether an input object is present and its positional information, as discussed above. A set of values for the capacitive pixels form a “capacitive image” (also “capacitive frame” or “sensing image”) representative of the capacitive couplings at the pixels. In various embodiments, the sensing image, or capacitive image, comprises data received during a process of measuring the resulting signals received with at least a portion of the sensing elements  121  distributed across the sensing region  120 . In one example, a capacitive image, or sensing image, comprises data received during a process of measuring the resulting signals received across all of the sensing elements  121  during a single scan cycle of the sensing region  120 . The resulting signals may be received at one instant in time, or by scanning the rows and/or columns of sensing elements distributed across the sensing region  120  in a raster scanning pattern (e.g., serially polling each sensing element separately in a desired scanning pattern), row-by-row scanning pattern, column-by-column scanning pattern or other useful scanning technique. 
     In some touch screen embodiments, the sensing elements  121  are disposed on a substrate of an associated display device. For example, the sensor electrodes  202  and/or the sensor electrodes  211  may be disposed on a polarizer, a color filter substrate, or a glass sheet of an LCD. As a specific example, the sensor electrodes  202  and  211  may be disposed on a TFT (Thin Film Transistor) substrate of an LCD type of the display device, a color filter substrate, on a protection material disposed over the LCD glass sheet, on a lens glass (or window), and the like. The electrodes may be separate from and in addition to the display electrodes, or may share functionality with the display electrodes. Similarly, an extra layer may be added to a display substrate or an additional process such as patterning applied to an existing layer. 
     Where sensor electrodes of each of the sensing elements  121  are disposed on a substrate within the display device (e.g., color filter glass, TFT glass, polyimide, etc.), the sensor electrodes may be comprised of a substantially transparent material (e.g., ITO, ATO, ClearOhm™, etc.) or they may be comprised of an opaque material and aligned with the pixels of the display device (e.g., a metal mesh). Electrodes may be considered substantially transparent in a display device if their reflection (and/or absorption) of light impinging on the display is such that human visual acuity is not disturbed by their presence. This may be achieved by matching indexes of refraction, making opaque lines narrower, reducing fill percentage or making the percentage of material more uniform, reducing spatial patterns (e.g., moiré) that are with visible to the human eye, and the like. 
     The processing system  110  of the input device  295  comprises a sensor controller  218  that is coupled through connectors  217  to each of the transmitter and receiver electrodes, such as sensor electrodes  202  and  211 , through one or more traces (e.g., traces  212  and  213 , respectively). The sensor controller  218  may transmit the transmitter signal and receive the resulting signals from receiver electrodes. The sensor controller  218  may also communicate the positional information received by the sensing elements  121  to the electronic system  150  and/or the display controller  233 , which is also coupled to the electronic system  150 . The sensor controller  218  may be coupled to the electronic system  150  using one or more traces  221  that may pass through a flexible element  251  and be coupled to the display controller  233  using one or more traces  221 A that may pass through the same flexible element  251  or a different connecting element, as shown. 
     The functions of the sensor controller  218  and the display controller  233  may be implemented in one integrated circuit that can control the display module elements and drive and/or sense data delivered to and/or received from the sensor electrodes. In various embodiments, calculation and interpretation of the measurement of the resulting signals may take place within the sensor controller  218 , display controller  233 , a host electronic system  150 , or some combination of the above. In some configurations, the processing system  110  may comprise transmitter circuitry, receiver circuitry, and memory that is disposed within one or any number of ICs found in the processing system  110 , depending to the desired system architecture. 
       FIG. 2B  shows a more detailed embodiment of the processing system  110  of the input device  295 . The sensor controller  218  includes a signal generating processor  255  and sensor processor  256  that work together to provide touch sensing data to an analysis module  290  and the electronic system  150 . The analysis module  290  may be part of the processing system  110 , the sensor processor  256  and/or part of the electronic system  150 . In various embodiments, the analysis module  290  comprises digital signal processing elements and/or other useful digital and analog circuit elements that are connected together to process the receiver channel output signal(s) received from at least one receiver channel that is coupled to a receiver electrode, and also provide processed signals to other portions of the electronic system  150 . The electronic system  150  may use the processed signals to control various aspects of the input device  295 . 
     As illustrated in  FIG. 2B , the signal generating processor  255  and the sensor processor  256  work together to provide receiver channel output signals to the analysis module  290  and/or the electronic system  150 . As discussed above, the positional information of an input object  140  ( FIG. 1 ) is derived based on the capacitance C S  (e.g., capacitance C S1 , C S2 , . . . C SN ) measured between each of the transmitter electrodes (e.g., sensor electrodes  202   1 ,  202   2 , . . .  202   N ) and the receiver electrodes (e.g., sensor electrodes  211   1 ,  211   2 , . . .  211   N ), wherein N is a positive integer. 
     Each of the transmitter electrodes (e.g., sensor electrodes  202   1 ,  202   2 , . . .  202   N  in  FIG. 2B ) is connected to a trace (e.g., traces  212   1 ,  212   2 , . . .  212   N  in  FIG. 2B ). Each trace has a certain amount of capacitance (e.g., transcapacitance) that is formed between the trace and the corresponding receiver electrode. As illustrated in  FIG. 2B , the capacitance between a trace and a receiver is given by capacitance C T  (e.g., capacitance CT 1 , CT 2 , . . . CT N ) and can be measured between each of the trace (e.g., traces  212   1 ,  212   2 , . . .  212   N ) and a receiver electrode (e.g.,  211   1 ,  211   2 , . . .  211   N ) at various points along the trace (e.g., Y-direction in  FIG. 2C ), where N is a positive integer. As shown, each trace capacitance CT (e.g., capacitance CT 1 , CT 2 , . . . CT N ) is in parallel with a transmitter capacitance Cs (e.g., capacitance C S1 , C S2 , . . . C SN ). Parasitic capacitance may result from an input object positioned over a trace (or background circuitry, such as display electrodes), where the input device detects a change in the capacitance at an associated pixel (e.g., sensed resulting signal provided by the associated sensing element  121 ), due to the change in the trace capacitance C T  (e.g., capacitance CT 1 , CT 2 , . . . CT N ). 
     In some embodiments, the signal generating processor  255  comprises a driver  228 , which is adapted to deliver capacitive sensing signals (transmitter signals) to the transmitter electrodes. In one configuration, the driver  228  may comprise a power supply and signal generator  220  that is configured to deliver a square, rectangular, trapezoidal, sinusoidal, Gaussian or other shaped waveforms used to form the transmitter signal(s) to the transmitter electrodes. In one configuration, the signal generator  220  comprises an electrical device, or simple switch, that is able to deliver a transmitter signal that transitions between the output level of the power supply and a low display voltage level. In various embodiments, signal generator  220  may comprise an oscillator. In some configurations, the signal generator  220  is integrated into the driver  222 , which includes one or more shift registers (not shown) and/or switches (not shown) that are adapted to sequentially deliver transmitter signals to one or more of the transmitter electrodes at a time. 
     In the example of  FIG. 2B , the sensor processor  256  comprises a plurality of receiver channels  275  (e.g., receiver channels  275   1 ,  275   2 , . . .  275   N ) each having a first input port  241  (e.g., ports  241   1 ,  241   2 , . . .  241   N ) that is configured to receive the resulting signal received with at least one receiver electrode (e.g., sensor electrode  211   1 ,  211   2 , . . .  211   N ), a second input port (e.g., ports  242   1 ,  242   2 , . . .  242   N ) that is configured to receive a reference signal delivered through the line  225 , and an output port coupled to the analysis module  290  and electronic system  150 . Typically, each receiver channel  275  is coupled to a single receiver electrode. Each of the plurality of receiver channels  275  may include a charge accumulator  276  (e.g., charge accumulators  276   1 ,  276   2 , . . .  276   N ), supporting components  271  (e.g., components  271   1 ,  271   2 , . . .  271   N ) such as demodulator circuitry, a low pass filter, sample and hold circuitry, other useful electronic components such as filters and analog/digital converters (ADCs) or the like. In some aspects, the charge accumulator  276  includes an integrator type operational amplifier (e.g., Op Amps A 1 -A N ) that has an integrating capacitance C fb  that is coupled between the inverting input and the output of the device. 
     Due to the type of electronic elements required to detect and process the received resulting signals, the cost required to form each receiver channel  275  is generally more expensive than the cost required to form the components in the signal generating processor  255  that provides the transmitter signal(s) to a transmitter electrode(s). However, in some embodiments, it may be desirable to reduce the number of transmitter electrodes to increase the scanning speed of the capacitive sensing type input device. In these configurations, it is generally desirable to maintain the same capacitive pixel density to maintain the input object position sensing accuracy. One skilled in the art will appreciate that delivering a capacitive sensing signal to a single transmitter electrode and then measuring the resulting signals on each of the receiver electrodes in the sensing region may provide a much faster capacitive sensing scanning process than sequentially delivering capacitive sensing signals in time to two or more transmitters then sensing the received resulting signals after each sequential scanning step. 
     Moreover, there is a benefit to reducing the number of traces used in an input device, since this will reduce the complexity and cost of the input device. The sensing region  120  may require hundreds or even thousands of sensing elements  121  to reliably sense the position of one or more input objects. The reduction in the number of traces that need to be routed to the various processing system  110  components is desirable for a number of reasons, which include a reduction in the overall cost of forming the input device  100 , a reduction in the complexity of routing the multitude of traces within the sensing region  120 , a reduced interconnecting trace length due to reduced routing complexity, a reduction in the cross-coupling of signals between adjacently positioned traces, and allowing for a tighter packing or increased density of sensor electrodes within the sensing region  120 . Reducing the number of traces may also reduce the amount of cross-coupling between the traces due to a reduction in the required trace density and number of traces that will transmit or receive signals delivered to or from adjacently positioned sensor electrodes or traces. 
     Aspects of the present disclosure describe an electrode array configuration that reduces or minimizes the number of traces and/or electrodes required to sense the position of an input object within the sensing region  120  using capacitive pixels that contain unique pairs of sensor electrodes to reliably determine the position of an input object. In some transcapacitive sensing embodiments, transmitter and/or receiver type sensor electrodes are interconnected together to reduce the number of traces that need to be coupled to the processing system components. Reducing the number of electrode connections, and thus supporting components (e.g., receiver channels), may allow for designs that can reduce the production cost and system complexity, even when a larger number of electrodes are required. 
       FIG. 2C  shows an example configuration of the sensing elements  121  of the input device  100 . As illustrated in  FIG. 2C , a sensor electrode (e.g., corresponding to one of the sensing elements  121 ) may generally comprise an electrode region and a trace. For example, the sensor electrodes depicted in  FIG. 2C  may include electrode regions  203  and  204  and traces  212  and  213 , respectively. For simplicity, only two transmitter electrodes ( 202   1 ,  202   2 ) are shown. In some aspects, each of the two sensing elements  121  illustrated in  FIG. 2C  comprises a transmitter electrode  202   1  or  202   2  and a portion of a group of the interconnected electrode regions  204  that form the receiver electrode  211 . The electrode regions  204  of the receiver electrode  211  interact with the electrode regions  203  of the two transmitter electrodes  202   1 ,  202   2  and two corresponding traces  212   1 ,  212   2  when a sensing signal is provided to the transmitter electrodes of each sensing element  121 . 
     The processing system  110  includes a signal generating processor  255  and a sensor processor  256  that work together to provide capacitive sensing receiver channel output signals to the analysis module  290  and electronic system  150 . As discussed above, the processing system derives the positional information of an input object  140  ( FIG. 1 ) based on the capacitance measured between each of the transmitter electrodes and the receiver electrodes contained in the sensing region  120 . In various embodiments, the sensor processor  256  may include digital signal processing elements and/or other useful digital and analog circuit elements that are connected together to process the receiver channel output signal(s) received from at least one receiver channel that is coupled to each of the receiver (Rx) electrodes  211 . In some aspects, the electronic system  150  may use the processed signals to control various aspects of the input device  295 . 
     In the example of  FIG. 2C , the signal generating processor  255  comprises a driver  228 , which is adapted to sequentially deliver capacitive sensing signals (transmitter signals) to the transmitter (Tx) electrodes  202   1 ,  202   2  in the array of sensing elements. In some embodiments, the sensor processor  256  comprises a plurality of receiver channel(s)  207  that each have a first input port  241  that is configured to receive the resulting signal received by at least one receiver electrode  211 , and an output port coupled to the analysis module  290 . Typically, each receiver channel  207 , which can be the same as a receiver channel  275  discussed above, may be coupled to a single receiver electrode  211 . In one configuration, the sensor processor  256  further comprises an electromagnetic interference (EMI) filter  299  that is adapted to filter EMI induced by other input device components. 
     Traces  212   1 ,  212   2  connect the driver  222  to the transmitter electrodes  202   1 ,  202   2 , respectively. For example, trace  212   1  connects the driver  222  to transmitter electrode  202   1  and trace  212   2  connects the driver  222  to transmitter electrode  202   2 . The capacitance between trace  212   1  and the receiver electrode  211  is associated with an electric field ETA. The capacitance between trace  212   2  and the receiver electrode  211  is associated with an electric field E T2 . The capacitance between transmitter electrode  202   1  and the receiver electrode  211  is associated with an electric field Est The capacitance between transmitter electrode  202   2  and the receiver electrode  211  is associated with an electric field E S2 . 
     When an input object (e.g., finger) is positioned near, such as over an electrode region  203  of a transmitter electrode  202   1 ,  202   2  and an electrode region  204  of a receiver electrode  211 , the associated trace may also see a change in capacitance (and corresponding electric field). For example, if an input object (e.g., finger) is in contact with, or hovers over, transmitter electrode  202   1 , the electric field E S1  tends to change, along with the electric field E T1  generated between trace  212   1  and the receiver electrode  211 . Likewise, if an input object (e.g., finger) is in contact with, or hovers over, transmitter electrode E S2 , the electric field E S2  tends to change along with the electric field E T2  generated between the trace  212   2  and the receiver electrode  211 . 
     Where an input object (e.g., finger) is near a trace  212   1 ,  212   2 , when a sensing signal is provided, a change in capacitance (and corresponding electric field) between the trace and the receiver electrode  211  will be measured by the sensor processor  256 . The position of the input object near a trace  212   1 ,  212   2  will cause a change in the electric field generated between the trace and the receiver electrodes, and thus affect the measured resulting signal measured by the sensor processor  256 . For example, if an input object (e.g., finger) is in contact with, or hovers over, trace  212   1 , the electric field E T1  tends to change, which is seen as a change in the resulting signal delivered by the transmitter electrode  202   1  to the receiver electrode  211 . Likewise, if an input object (e.g., finger) is in contact with, or hovers over, trace  212   2 , the electric field E T2  tends to change, which is seen as a change in the resulting signal delivered by the transmitter electrode  202   2  to the receiver electrode  211 . The capacitance changes at the traces  212   1 ,  212   2  may also affect the capacitive coupling of the connected transmitter electrode(s)  202   1 ,  202   2  to the receiver electrode  211 , respectively. Such capacitance changes associated with an input object (e.g., finger) being over a trace may be referred to as “parasitic capacitance.” As further described below, the input device is configured to correct parasitic capacitance in order to carry out object detection algorithms more accurately. 
       FIG. 3  shows a single-layer sensor electrode configuration, in accordance with some embodiments. More specifically,  FIG. 3  depicts a portion of a sensing region  120  formed on a substrate  209  that includes a plurality of sensor electrodes that are used to sense the position of an input object within the sensing region  120  using a transcapacitive sensing method. The input device includes two arrays of transmitter electrodes  316  and two receiver electrodes  311 . The first array of transmitter electrodes  316   1  includes transmitter electrodes  302 A- 302 D that are each coupled to a separate trace  301  and the second array of transmitter electrodes  316   2  include transmitter electrode regions  302 E- 302 H that are each coupled to a separate trace  301 . In the example of  FIG. 3 , the input device is shown to include one receiver electrode  311   1  that is positioned to directly couple with the transmitter electrodes  302 A- 302 D in the first array of transmitter electrodes  316   1  and only one receiver electrode  311   2  that is positioned to directly couple with the transmitter electrode regions  302 E- 302 H in the second array of transmitter electrodes  316   2 . However, the configuration of sensor electrodes shown in  FIG. 3  is not intended to be limiting as to the scope of the disclosure. 
     As described above, to reduce the overall cost of forming the input device  100 , reduce the system complexity, reduce the cross-coupling of signals between adjacently positioned traces and the costs to detect and process the resulting signals generated during a capacitive sensing process, the receiver electrodes  311   1  and  311   2  are electrically coupled together, such that a single trace  302  is connected to the processing system  110  components (not shown), such as the sensor controller  218  (not shown). A reduction in the cost of the overall input system can be realized by reducing the number of electrode traces, especially by reducing the number of traces that are coupled to receiver electrodes, due to the cost required to form the components used to receive and process the received resulting signals. Therefore, in some embodiments, at least two sensor electrodes may be connected to two or more sensor electrodes in two different arrays of sensor electrodes, that are positioned a distance apart from each other within the sensing region  120 . 
     By interconnecting the sensor electrodes prior to their connection to the processing system  110 , the number of traces that are required to couple with the processing system  110  components may be reduced. For example, the traces of multiple receiver electrodes may be electrically coupled to reduce the number of required connections made to the signal processing components within the sensor processor  256  (e.g., receiver channels  275 ) in the processing system  110 . As a result, the ratio of the number of transmitter traces to receiver traces is greater than one. By coupling the receiver electrodes together, the number of required receiver channels will be reduced, thus reducing the cost and complexity of the processing system  110 . However, in some configurations, it may also be desirable to have more transmitter electrodes regions than receiver electrodes regions (e.g., ratio of transmitter electrodes to receiver electrodes is greater than one), since a fully enabled transmitter electrode generally costs less to manufacture than a fully enabled receiver electrode. 
     In some implementations, the traces of multiple transmitter electrodes may be electrically coupled together to reduce the number of required connections made to the signal driving components within the generating processor  255  in the processing system  110  and/or to improve the scanning speed of the input device. In yet another example, the number of traces used to couple the transmitter electrodes and the receiver electrodes to their various signal processing components may be reduced by interconnecting the traces of each type of electrode. However, coupling both types of transcapacitive sensing electrodes to electrodes of the same type (e.g., transmitter electrodes to transmitter electrodes and receiver electrodes to receiver electrodes) can lead to capacitive sensing issues associated with correctly determining the position of an input object. Therefore, as will be discussed further below, some embodiments include interconnected electrodes that only form unique pairs of transmitter and receiver electrodes. 
     In some sensor electrode configurations, as illustrated in  FIG. 3 , the interconnection between some types of sensor electrodes, such as receiver electrodes  311   1  and  311   2 , can produce misleading or false input object position determination(s) by the processing system. The misleading or false determination of the input objects position can be due to the cross-coupling between transmitter electrodes and/or transmitter electrode traces and the two or more receiving electrodes that are interconnected together within the sensing region  120 . 
     For example, due to the interconnection of the two receiver electrodes  311   1  and  311   2 , as shown in  FIG. 3 , the processing system may not be able to determine whether an input object  140  is in the first input object position  140   1  or in the second input object position  140   2 . This problem may arise from the cross-coupling of the trace  301 H and the first receiver electrode  311   1  and the intended direct coupling of the electrode region  302 H and the second receiver electrode  311   2 , since the processing system  110  may be unable to determine whether the input object is over the first receiver electrode  311   1  or the second receiver electrode  311   2 . It is noted that, when the sensor electrode region  302 H is driven for capacitive sensing, the trace  301 H will capacitively couple to the first sensor electrode  311   1  (e.g., within region P 1 ) and the electrode region  302 H will directly couple to the second sensor electrode  311   2 . Since the input object could be in more than one position within the sensing region  120  (e.g., input object position  140   1  or  140   2 ), and still provide the same or a similar resulting signal to the sensor processor portion of the processing system, it may not be possible to determine the actual position of the input object. 
     Therefore, in some embodiments, a revised sensor electrode layout may be able to accurately sense the position of an input object  140 , while also having a reduced number of interconnecting traces is needed.  FIGS. 4-8  illustrate a few examples of various configurations that can be used to meet these goals. These examples are provided herein to help explain various aspects of the embodiments and are not intended to limit the scope of the disclosure. While  FIGS. 4-8  illustrate a sensor electrode configuration that includes one or more arrays of receiver electrodes that are interconnected to form two groups of sensor electrodes, this configuration is not intended to be limiting as to the scope of the disclosure. One skilled in the art will appreciate that one or more of the arrays of sensor electrodes could be formed so that it contains fewer or more groups of receiver electrodes that contain one or more sensor electrodes without deviating from the scope of the disclosure. 
     Also, while  FIGS. 4-8  illustrate a sensor electrode configuration that includes one or more arrays of transmitter electrodes, such as arrays of sensor electrodes  415 , which contain a plurality of sensor electrodes  402 , for example may include sensor electrode regions  402 A- 402 H ( FIG. 4 ), that are each separately connected to the processing system  110  through a trace  412 , this configuration is not intended to be limiting as to the scope of the disclosure. One skilled in the art will appreciate that one or more of the separately connected traces  412  can be interconnected inside or outside of the sensing region  120  before they are coupled with the processing system  110  components without deviating from the scope of the disclosure. 
       FIG. 4  shows a single-layer sensor electrode configuration including two sets of sensor electrode arrays, in accordance with some embodiments. More specifically,  FIG. 4  shows a portion of a sensing region  120  formed on a substrate  209  that includes a plurality of sensor electrodes that are used to accurately sense the position of an input object within the sensing region  120  using a transcapacitive sensing method. The input device in this example includes two sets of sensor electrode arrays  420   1 ,  420   2  each including an array of transmitter electrodes  415   1  or  415   2  and an array of receiver electrodes  416   1  or  416   2 . 
     The first array of transmitter electrodes  415   1  includes transmitter electrode regions  402 A- 402 D that are each coupled to a separate trace  412  and the second array of transmitter electrodes  415   2  includes transmitter electrode regions  402 E- 402 H that are each coupled to a separate trace  412 . The first array of receiver electrodes  416   1  and second array of receiver electrodes  416   2  each include a plurality of sensor electrodes that include receiver electrode regions  411 A,  411 B and traces  413 A,  413 B. The receiver electrode regions  411 A and  411 B in the first and second electrode arrays  416   1 ,  416   2  are each separately coupled together using a trace  413 A or  413 B, respectively. 
     By coupling the sensor electrodes in the first and second arrays of receiver electrodes  416   1 ,  416   2  together, the number of required connections to the processing system  110  is reduced. For example, a conventional sensing electrode design that requires one trace per receiver electrode would require 10 separate traces and connections (e.g., 10 electrode regions  411 A and  411 B) to the processing system  110  components ( FIG. 2A ), such as the sensor controller  218  ( FIG. 2A ). By connecting the sensor electrodes in the first and second arrays of receiver electrodes into one or more groups of sensor electrodes the number of separate traces and connections can be reduced. 
     In the example of  FIG. 4 , two groups of interconnected sensor electrodes are formed by interconnecting the electrode regions  411 A and  411 B using the traces  413 A and  413 B, respectively, in each array of sensor electrodes. Therefore, each of the two groups of electrodes in the arrays of sensor electrodes  416   1 ,  416   2  are interconnected via the interconnection traces  413 AA,  413 BB, respectively, so that only two separate traces  423 A and  423 B are required to separately connect the two groups of sensor electrodes with the processing system  110  components. 
     Due to the separate interconnection of transmitter electrode configuration, as illustrated in  FIG. 4 , each of the formed sensing elements contain unique pairs of transmitter and receiver electrodes that have a reduced total interconnection trace count from most conventional electrode configurations. As noted above, the embodiments herein may provide an electrode configuration that comprises multiple arrays of capacitive pixels that each includes unique pairs of sensor electrodes to reliably determine the position of an input object. Unique pairs to sensor electrodes generally include configurations where a first pair of sensor electrodes in a first capacitive pixel are both not interconnected with another pair of sensor electrodes in any of the other capacitive pixels in the sensing region. 
     For example, a pixel that includes a portion of the sensor electrode region  402 D and a portion of sensor electrode region  411 B in the array of sensor electrodes  415   1  may not be unique from a pixel that includes a portion of the sensor electrode region  402 G and a portion of sensor electrode region  411 B in the array of sensor electrodes  415   2  if the traces  412 D and  412 G were connected together so that these sensor electrodes send or receive capacitive sensing signals at the same time, since both of the electrodes of the same type are connected together and are used in the same two pixels (e.g., electrode regions  402 D and  402 G are connected together and electrode regions  411 B in the array of sensor electrodes  415   1  and electrode regions  411 B in the array of sensor electrodes  415   2  are connected together via the interconnection trace  413 BB). The presence of non-unique directly coupled pairs of sensing electrodes may lead to false and misleading input object position determinations as discussed above. 
     In some embodiments, the arrays of transmitter electrodes  415 , and their associated traces  412 , are positioned next to each other with no intervening array(s) of receiver electrodes  416  between them. By positioning the arrays of transmitter electrodes  415  and associated traces  412  next to each other, the cross-coupling of the traces  412  and either of the arrays of receiver electrodes  416   1 ,  416   2  is minimized, and the cross-coupling of transmitter electrodes in an array of transmitter electrodes that are not positioned to directly couple with the arrays of receiver electrodes  416   1 ,  416   2  is avoided. In this configuration, the arrays of transmitter electrodes  415  and associated traces  412  are positioned next to each other and are disposed between two or more arrays of receiver electrodes  416 . In one example, when the sensor electrode region  402 H is driven for capacitive sensing, the trace  412 H is not positioned so that it will capacitively couple to the first sensor electrode region  411 A or the second sensor electrode region  411 B in the first or second arrays of sensor electrodes  415   1  or  415   2 . 
     In some embodiments, two or more arrays of transmitter electrodes (e.g., arrays  415   1  and  415   2 ) are positioned adjacent to each other so that the gaps between the electrode regions  402 A- 402 D and electrode regions  402 E- 402 H is minimized by reducing the gaps formed between the traces and transmitter electrodes, while still being ohmically isolated from each other. The reduction in the gaps formed between the traces and transmitter electrodes will also improve the density of sensing elements  121  formed within the sensing region  120 . In this example, one sensing element  121  is formed between electrode region  402 D and the uppermost electrode region  411 A in the first array of receiver electrodes  416   1  and another sensing element  121  is adjacently formed between electrode region  402 H and the uppermost electrode region  411 A in the second array of receiver electrodes  416   2 . 
     In some sensor electrode configurations discussed herein, the arrays of sensor electrodes (e.g., transmitter and/or receiver electrodes) include a plurality of sensor electrode regions (e.g., electrode regions  402 A- 402 D or  411 A- 411 B) that are aligned along a first direction, such as the Y-direction shown in  FIG. 4 . In one example, the centroid of the area of the electrode regions in an array of sensor electrodes (e.g., electrode regions  402 A- 402 D) are aligned along a first direction. In another example, an edge of the electrode regions in an array of sensor electrodes are aligned along a first direction. In yet another example, where the edge(s) of the electrode regions are non-linear, the alignment of the electrode regions may be found by comparing the orientation and alignment of the major axis of symmetry of the electrode regions. 
     In some embodiments, two or more arrays of sensing electrodes (e.g., arrays of sensor electrodes  415   1  and  415   2 ) are positioned adjacent to each other and are symmetric about a linear (e.g., axis) and/or non-linear symmetry line, so that a regular pattern of sensing elements  121  are formed across the sensing region  120 . In one example, as shown in  FIG. 4 , the first array of transmitter electrodes  415   1  and second array of transmitter electrodes  415   2  are symmetric about a symmetry line  401 , which in this example happens to be linear. As illustrated in  FIG. 4 , the electrode regions  402 A- 402 D, and their associated traces  412 , and electrode regions  402 E- 402 H, and their associated traces  412 , are also mirror images of each other. Also, in some configurations, the sets of sensor electrode arrays  420   1 ,  420   2  may be positioned a distance apart in a second direction (e.g., X-direction) that is orthogonal to or at an angle with a first direction that is parallel to the symmetry line and/or parallel to an alignment direction of an array of sensor electrodes (e.g., Y-direction for the electrode regions  402 A- 402 D). 
     Due to the layout of the sensing electrodes disclosed herein, an input object  140  that is positioned over or near the electrode region  402 E and traces  412  will primarily couple to the receiving electrodes in the second array of receiver electrodes  416   2 . Thus, by orienting the electrodes in this way the cross-coupling of the input object and the other connected receiver electrodes in the first array of receiver electrodes  416   1  is reduced or completely removed. 
     In the example of  FIG. 5 , the arrays of receiver electrodes  416 , and their associated traces  413 A- 413 B, are positioned next to each other with no intervening array(s) of transmitter electrodes  415  positioned between them. The input device depicted in  FIG. 5  includes four sets of sensor electrode arrays  520   1 - 520   4  that each contain two or more arrays of sensor electrodes, such as a first array of transmitter electrodes  415 A and a first array of receiver electrodes  416 A. By positioning the arrays of receiver electrodes and their associated traces next to each other, the cross-coupling of the arrays of receiver electrodes and non-directly coupled electrode regions is minimized, and the problem of false or misleading input object position determination can be eliminated. 
     In some embodiments, one or more groups of sensor electrodes in an array of sensor electrodes that are positioned within a first set of sensor electrode arrays are coupled with one or more groups of sensor electrodes in an array of sensor electrodes that are positioned within a second set of sensor electrode arrays to help reduce the number of traces that are required to sense the position of an input object within the sensing region  120 . For example, as illustrated in  FIG. 5 , a first group of receiver electrodes  414 A, which includes electrode regions  411 A, in the first array of receiver electrodes  416 A, is coupled to the first group of receiver electrodes  414 C, which include electrode regions  411 A, in the third array of receiver electrodes  416 C, using the trace  413 AA. In general, the one or more groups of sensor electrodes in different sets of sensor electrode arrays can be connected together to reduce the number of traces and complexity of the processing system. In some embodiments, at least one electrode region in a first array of receiver electrodes is interconnected with at least one electrode region in a second array of receiver electrodes, which are disposed in the sensing region  120 . 
     With reference to  FIG. 5 , the arrays of receiver electrodes  416 A and  416 B and arrays of receiver electrodes  416 C and  416 D, and their associated traces  413 A- 413 B, are positioned near to each other (e.g., adjacent to each other). In this configuration, the arrays of receiver electrodes  416  and associated traces are positioned next to each other and are disposed between two or more arrays of transmitter electrodes  415 . Thus, when the sensor electrode region  402 H is driven for capacitive sensing, the trace  412 H is positioned so that it will essentially not capacitively couple to the first sensor electrode region  411 A or the second sensor electrode region  411 B in the second array of receiver electrodes  416   2  or the first sensor electrode region  411 A or the second sensor electrode region  411 B in the first or third array of receiver electrodes  416   1  or  416   3 . 
       FIG. 6A  shows a single-layer sensor electrode configuration including four sets of sensor electrode arrays, in accordance with some other embodiments. More specifically, in the example of  FIG. 6A , each of the sets of sensor electrode arrays  620   1 - 620   4  include an array of receiver electrodes  416 , and their associated traces  413 A- 413 B or  413 C- 413 D, that are positioned between array(s) of transmitter electrodes  415 . In one example, a first set of sensor electrode arrays  620   1  includes three arrays of sensor electrodes, such as a first array of transmitter electrodes  415 A, a first array of opposing transmitter electrodes  417 A and a first array of receiver electrodes  416 A. 
     Aspects of the present disclosure recognize that positioning an array of one type of sensing electrode between at least two arrays of another type of sensing electrodes (e.g., that form unique pixels), such as an array of receiving electrodes between two arrays of transmitter electrodes or vice versa, the physical orientation of the different types of sensor electrodes can help shield or minimize the cross-coupling of electrodes that are positioned a distance away from the set of electrode arrays, and thus prevent the mischaracterization the position of an input object when electrodes in two or more different sets of sensor electrode arrays are connected together. Further, positioning an array of one type of sensing electrode between at least two arrays of another type of sensing electrodes will create a symmetric electric field between the electrodes when the center electrode is driven relative to the two outer electrodes or the two outer electrodes are driven relative to the inner electrode, which may improve the quality of the capacitive sensing signal and process. 
       FIG. 6B  show another single-layer sensor electrode configuration including four sets of sensor electrode arrays, in accordance with some other embodiments. More specifically,  FIG. 6B  illustrates an example electrode configuration that is formed in each of the sets of sensor electrode arrays  620   1 - 620   4  to create a symmetric electric field between pairs of opposing electrodes during operation of the input device. In this example, the electrodes  402  in the same row, such as electrodes  402 D and  402 H, electrodes  402 L and  402 P, electrodes  402 C and  402 G, etc. are each coupled together to form a symmetric electrode configuration relative to an opposing electrode  411 . 
     It is noted that the number of traces  412  that need to be connected to the processing system components  110 , in the example of  FIG. 6B , is halved (compared to  FIG. 6A ) due to the interconnection of the electrodes  402  positioned in each row. In this configuration, only traces  412 A-D are routed and connected to the processing system components, which is a smaller subset of the number of traces  412  shown in  FIG. 6A . Further, when the electrodes  402  (e.g., electrodes  402 D and  402 H) are driven relative to the electrodes  411  (e.g., electrodes  411 A and/or  411 B), or vice versa, the electric fields created between each of the electrodes  402  and the centrally positioned electrode  411  will be symmetric. Thus, as noted above, the quality of the capacitive sensing signal may be improved and the cost and complexity of the input device can be reduced due to the reduction in the number of required traces and capacitive sensing channels. 
     As illustrated in  FIGS. 6A and 6B , at least one electrode region in a first array of receiver electrodes in a first set of sensor electrode arrays is interconnected with at least one electrode region in a second array of receiver electrodes in a second set of sensor electrode arrays, which are all disposed in the sensing region  120 . By positioning the arrays of receiver electrodes and their associated traces between two arrays of transmitter electrodes that are positioned to directly couple to the receiver electrodes in the array of receiving electrodes, the cross-coupling of the arrays of receiver electrodes and other non-directly coupled transmitter electrode regions is minimized. In one example, when the sensor electrode region  402 L is driven for capacitive sensing, the trace  412 L is positioned so that it will not capacitively couple to the first sensor electrode region  411 A or the second sensor electrode region  411 B in the first array of receiver electrodes  416 A or the first sensor electrode region  411 A or the second sensor electrode region  411 B in the third array of receiver electrodes  416 C. 
     In some embodiments, two or more traces may be coupled together within the sensing region  120  to further reduce the number of connections that are required to make to the processing system  110  components. For example, as illustrated in  FIG. 6A , the traces  402 H and  402 L,  402 P and  402 T, and  402 X and  402 BB may be connected together to reduce the number of traces  412  that are required to connect the electrode regions to the processing system components. In this example, the total number of required traces  412  that are coupled to the processing components can be reduced by four traces. 
       FIGS. 7 and 8  illustrate a sensing region  120  of an input device  100  that is divided up into sectors  721  or  821  that are each configured to contain at least one set of sensor electrode arrays. For clarity of discussion, only three of the sectors  721  in  FIG. 7  and three of the sectors  821  in  FIG. 8  have a set of sensor electrode arrays shown therein. However, one skilled in the art will appreciate that each of the sectors  721  shown in  FIGS. 7 and 8  could have at least one set of senor electrode arrays disposed therein. Moreover, at least one electrode in each of these sets of sensor electrode arrays could be coupled with one or more electrodes in another set of sensor electrode arrays disposed in the same sector or other sectors within the sensing region  120 . These electrode configurations may also include multiple arrays of capacitive pixels that each includes unique pairs of sensor electrodes. 
     As illustrated in  FIG. 7 , three sets of sensor electrode arrays  720   1 - 720   3 , which are positioned three sectors  721  away from each other, are coupled together to reduce the total number of traces (e.g., traces  412  and  413 ) that need to be connected to the processing system components (not shown). In this example, at least one electrode in each of the horizontally oriented three sets of sensor electrode arrays are coupled together using an interconnect  714  that is coupled to the traces  413  (e.g., trace  413 A in  FIG. 6A ) in each set of sensor electrode arrays to reduce the number of traces (e.g., traces  412  and/or  423 ) that are required to connect each of the sensor electrode regions to the processing system components. Sectors on either side of the substrate  209  (e.g. left and right in the X-direction or top and bottom in the Y-direction) may be routed to their nearby edges or outside of the viewable area (e.g. Active Area) of the display, thereby reducing the required routing width and parasitic capacitive coupling. 
     As illustrated in  FIG. 8 , three sets of sensor electrode arrays  820   1 - 820   3 , which are positioned three sectors  821  away from each other, are coupled together to reduce the total number of traces that need to be connected to the processing system components (not shown). In this example, at least one electrode in each of the three vertically oriented sets of sensor electrode arrays are coupled together using an interconnect  814  that is coupled to the traces  413  (e.g., trace  413 A in  FIG. 6A ) in each set of sensor electrode arrays to reduce the number of traces (e.g., traces  412  and/or  423 ) that are required to connect each of the sensor electrode regions to the processing system components. 
     With reference to  FIGS. 6A, 6B, 7 and 8 , it is noted that the number of traces may be further reduced, while still achieving a symmetric electric field, by alternating the columns of transmit and receive electrodes, and grouping the sensor electrodes, such that at least one receive (or transmit) electrode is disposed between two transmit (or receive) electrodes that operate concurrently in each group. As described above, in conventional capacitive sensing applications, the array of sensor electrodes is scanned progressively (e.g., row-by-row) to generate a capacitive image. However, when multiple receive (RX) electrodes are capacitively coupled to each transmit (TX) electrode, the number of different RX channels needed to process a single row of the sensor array grows significantly relative to the number of TX electrodes in each row. Thus, it may be desirable to reduce the granularity of the scanning operation so that localized groups of TX electrodes can be activated at a time, without having to activate an entire row of the sensor array at once. 
       FIG. 9  shows a capacitive sensing array  900 , in accordance with some other embodiments. In the example of  FIG. 9 , a plurality of sensor electrodes T 1 -T 12  and R 1 -R 12  are arranged in rows  921 - 924  and columns  901 - 917  in a single-layer or coplanar configuration. For purposes of discussion, the larger electrodes T 1 -T 12  are referred to as TX electrodes and the smaller electrodes R 1 -R 12  are referred to as RX electrodes. However, in actual implementations, any of the larger electrodes T 1 -T 12  may perform the functions of RX electrodes and any of the smaller electrodes R 1 -R 12  may perform the functions of TX electrodes. TX electrodes with the same electrode number (e.g., T 1 , T 2 , T 3 , etc.) may be coupled to the same TX channel and RX electrodes with the same electrode number (e.g., R 1 , R 2 , R 3 , etc.) may be coupled to the same RX channel. Thus, in the example of  FIG. 9 , the capacitive sensing array  900  includes 12 different TX channels and 12 different RX channels. 
     In some embodiments, the TX electrodes (and RX electrodes) are arranged in localized groups. For example, a group of first TX electrodes (T 1 ) is disposed in columns  901 ,  903 , and  905  of the first row  921  of the array  900 . The T 1  electrodes may be coupled to a first TX channel, and may thus be driven at the same time (e.g., concurrently) when the first TX channel is activated during a scan of the capacitive sensing array  900 . Each of the T 1  electrodes is adjacent to at least four RX electrodes R 1 -R 4 , R 5 -R 8 , and R 9 -R 12  disposed in columns  902 ,  904 , and  906 , respectively, of row  921 . Thus, when the first TX channel is activated, the RX electrodes R 1 -R 12  may detect a unique capacitive coupling from the adjacent T 1  electrodes. More specifically, the RX electrodes R 1 -R 4  in column  902  may detect a symmetric electric field (e.g., produced by the T 1  electrodes in columns  901  and  903 ) and the RX electrodes R 5 -R 8  may also detect a symmetric electric field (e.g., produced by the T 1  electrodes in columns  903  and  905 ). 
     A group of second TX electrodes (T 2 ) is disposed in columns  901 ,  903 , and  905  of the second row  922  of the array  900 . The T 2  electrodes may be coupled to a second TX channel, and may thus be driven at the same time when the second TX channel is activated. Each of the T 2  electrodes is adjacent to at least four RX electrodes R 1 -R 4 , R 5 -R 8 , and R 9 -R 12  disposed in columns  902 ,  904 , and  906 , respectively, of row  922 . Thus, when the second TX channel is activated, the RX electrodes R 1 -R 12  may detect a unique capacitive coupling from the adjacent T 2  electrodes. As shown in  FIG. 9 , the order of the RX electrodes in a given column is reversed for each successive row. For example, the R 4  electrode adjacent to T 1  is at the bottom of row  921 , whereas the R 4  electrode adjacent to T 2  is at the top of row  922 . Accordingly, spill-over electric field emitted by T 1  may be detected by R 4  in row  922  and combined with the electric field detected by R 4  in row  921 . Similarly, spill-over electric field emitted by T 2  may be detected by R 4  in row  921  and combined with the electric field detected by R 4  in row  921 . 
     In the embodiment of  FIG. 9 , the T 1  and T 2  electrodes do not span the entire rows  921  and  922 , respectively, of the array  900 . Thus, the RX channels may be repeated (or reused) beginning at column  908 . This allows the number of RX channels to be limited to  12 . For example, a group of fifth TX electrodes (T 5 ) is disposed in columns  907 ,  909 , and  911  of the first row  921 . Each of the T 1  electrodes is adjacent to eight RX electrodes R 9 -R 12 , R 1 -R 4 , R 5 -R 8 , and R 9 -R 12  disposed in columns  906 ,  908 ,  910 , and  912 , respectively, of row  921 . Thus, when the fifth TX channel is activated, the RX electrodes R 1 -R 12  may detect a capacitive coupling from the adjacent T 5  electrodes. In contrast, if the entire first row  921  of TX electrodes (e.g., in columns  901 ,  903 ,  905 ,  907 ,  909 ,  911 ,  913 ,  915 , and  917 ) were driven concurrently, the input device would require 32 different RX channels to uniquely detect an input object. 
     Aspects of the present disclosure recognize that, when the T 5  electrodes are driven, the RX electrodes R 9 -R 12  in column  906  and in column  912  of row  921  may simultaneously detect changes in capacitive coupling with adjacent T 5  electrodes in columns  97  and  911 , respectively. As a result, the processing system of the input device may be unable to uniquely identify the location of an input object in columns  906  or  912  of the array  900 . For example, when the R 9  electrode in column  906  senses a change in capacitance (e.g., exceeding a threshold amount), the change in capacitance may register on the ninth RX channel at the receiver (e.g., the channel associated with all R 9  electrodes in the array). As a result, the processing system may be unable to discern whether an input object was detected by the R 9  electrode in column  906  or the R 9  electrode in column  912 , or both. Thus, in some embodiments, it may be desirable to alter the configuration of RX electrodes at the edges or borders of different TX groups. 
       FIG. 10  shows a single-layer capacitive sensing array  1000  with a unique mapping of transmit and receive channels, in accordance with some embodiments. In the example of  FIG. 10 , a plurality of sensor electrodes T 1 -T 12  and R 1 -R 16  are arranged in rows  1021 - 1024  and columns  1001 - 1017  in a single-layer or coplanar configuration. For purposes of discussion, the larger electrodes T 1 -T 12  are referred to as TX electrodes and the smaller electrodes R 1 -R 16  are referred to as RX electrodes. However, in actual implementations, any of the larger electrodes T 1 -T 12  may perform the functions of RX electrodes and any of the smaller electrodes R 1 -R 16  may perform the functions of TX electrodes. TX electrodes with the same electrode number (e.g., T 1 , T 2 , T 3 , etc.) may be coupled to the same TX channel and RX electrodes with the same electrode number (e.g., R 1 , R 2 , R 3 , etc.) may be coupled to the same RX channel. Thus, in the example of  FIG. 10 , the capacitive sensing array  1000  includes 12 different TX channels and 16 different RX channels. 
     In some embodiments, the TX electrodes (and RX electrodes) are arranged in localized groups. For example, a group of first TX electrodes (T 1 ) is disposed in columns  1001 ,  1003 , and  1005  of the first row  1021  of the array  1000 . As described above, the T 1  electrodes may be coupled to a first TX channel and may thus be driven at the same time (e.g., concurrently) when the first TX channel is activated during a scan of the capacitive sensing array  1000 . Each of the T 1  electrodes is adjacent to at least four RX electrodes R 1 -R 4 , R 5 -R 8 , and R 9 -R 12  disposed in columns  1002 ,  1004 , and  1006 , respectively, of row  1021 . Thus, when the first TX channel is activated, the RX electrodes R 1 -R 12  may detect a unique capacitive coupling from the adjacent T 1  electrodes. 
     A group of second TX electrodes (T 2 ) is disposed in columns  1001 ,  1003 , and  1005  of the second row  1022  of the array  1000 . The T 2  electrodes may be coupled to a second TX channel, and may thus be driven at the same time when the second TX channel is activated. Each of the T 2  electrodes is adjacent to at least four RX electrodes R 1 -R 4 , R 5 -R 8 , and R 9 -R 12  disposed in columns  1002 ,  1004 , and  1006 , respectively, of row  1022 . Thus, when the second TX channel is activated, the RX electrodes R 1 -R 12  may detect a unique capacitive coupling from the adjacent T 2  electrodes. As shown in  FIG. 10 , the order of the RX electrodes in a given column is reversed for each successive row. For example, the R 4  electrode adjacent to T 1  is at the bottom of row  1021 , whereas the R 4  electrode adjacent to T 2  is at the top of row  1022 . 
     Further, a group of fifth TX electrodes (T 5 ) is disposed in columns  1007 ,  1009 , and  1011  of the first row  1021 . Each of the T 5  electrodes is adjacent to eight RX electrodes R 9 -R 12 , R 1 -R 4 , R 5 -R 8 , and R 13 -R 16  disposed in columns  1006 ,  1008 ,  1010 , and  1012 , respectively, of row  1021 . Thus, when the T 5  electrodes are driven, the RX electrodes R 1 -R 16  may detect a unique capacitive coupling from the adjacent T 5  electrodes. Because none of the RX electrodes adjacent to the T 5  electrodes are reused or repeated, and because the RX electrodes R 13 -R 16  on the right-most edge (e.g., column  1012 ) of the T 5  group of electrodes are coupled to different RX channels than the RX electrodes R 9 -R 12  on the left-most edge (e.g., column  1006 ) of the T 5  group, each of the RX channels will detect a unique capacitive coupling between the RX electrodes R 1 -R 16  and adjacent T 5  electrodes. 
     Thus, by increasing the number of RX channels by 4 (compared to the sensor configuration  900  of  FIG. 9 ), the sensor configuration  1000  may uniquely identify input objects at any position within the sensing region. More generally, assuming a maximum number (m) of TX electrodes in each TX group and a number (n) of RX electrodes disposed between each pair of TX electrodes in the sensor array, the total number of distinct RX channels in the sensor electrode configuration  1000  is equal to n+n*m. With reference for example to  FIG. 10 , there are 3 TX electrodes in each group (m=3) and 4 RX electrodes adjacent to each TX electrode (n=4). Thus, the total number of RX channels is equal to 4+3*4=16. 
     As described above, parasitic capacitances may affect the capacitive coupling between TX electrodes and RX electrodes. In particular, a parasitic background capacitance (e.g., from display electrodes or other circuitry disposed on or adjacent to the input device) may persist each time the sensor electrodes are scanned. As a result, the parasitic background capacitance may affect the charge accumulated in the receiver across each of the RX channels (e.g., for respective RX electrodes R 1 -R 16 ). However, in the example of  FIG. 10 , there is an unequal distribution of RX electrodes R 1 -R 16 . More specifically, there are triple the number of RX electrodes R 1 -R 8  as RX electrodes R 9 -R 12  or R 13 -R 16 . This may result in an imbalance in background capacitances detected across the different RX channels. For example, the first eight RX channels (e.g., coupled to RX electrodes R 1 -R 8 ) may sense three times the amount of background capacitance as any of the last eight RX channels (e.g., coupled to RX electrodes R 9 -R 16 ) each time the sensor electrodes are scanned. This imbalance in capacitive background coupling may lead to errors in input detection at various points in the sensing region. 
       FIG. 11  shows a single-layer capacitive sensing array  1100  with balanced capacitive background coupling, in accordance with some embodiments. In the example of  FIG. 11 , a plurality of sensor electrodes T 1 -T 12  and R 1 -R 16  are arranged in rows  1121 - 1124  and columns  1101 - 1117  in a single-layer or coplanar configuration. For purposes of discussion, the larger electrodes T 1 -T 12  are referred to as TX electrodes and the smaller electrodes R 1 -R 16  are referred to as RX electrodes. However, in actual implementations, any of the larger electrodes T 1 -T 12  may perform the functions of RX electrodes and any of the smaller electrodes R 1 -R 16  may perform the functions of TX electrodes. TX electrodes with the same electrode number (e.g., T 1 , T 2 , T 3 , etc.) may be coupled to the same TX channel and RX electrodes with the same electrode number (e.g., R 1 , R 2 , R 3 , etc.) may be coupled to the same RX channel. Thus, in the example of  FIG. 11 , the capacitive sensing array  1100  includes 12 different TX channels and 16 different RX channels. 
     In some embodiments, the TX electrodes (and RX electrodes) are arranged in localized groups. For example, a group of first TX electrodes (T 1 ) is disposed in columns  1101 ,  1103 , and  1105  of the first row  1121  of the array  1100 . As described above, the T 1  electrodes may be coupled to a first TX channel and may thus be driven at the same time (e.g., concurrently) when the first TX channel is activated during a scan of the capacitive sensing array  1100 . Each of the T 1  electrodes is adjacent to at least four RX electrodes R 1 -R 4 , R 5 -R 8 , and R 9 -R 12  disposed in columns  1102 ,  1104 , and  1106 , respectively, of row  1121 . Thus, when the first TX channel is activated, the RX electrodes R 1 -R 12  may detect a unique capacitive coupling from the adjacent T 1  electrodes. 
     A group of second TX electrodes (T 2 ) is disposed in columns  1101 ,  1103 , and  1105  of the second row  1122  of the array  1100 . The T 2  electrodes may be coupled to a second TX channel, and may thus be driven at the same time when the second TX channel is activated. Each of the T 2  electrodes is adjacent to at least four RX electrodes R 1 -R 4 , R 5 -R 8 , and R 9 -R 12  disposed in columns  1102 ,  1104 , and  1106 , respectively, of row  1122 . Thus, when the second TX channel is activated, the RX electrodes R 1 -R 12  may detect a unique capacitive coupling from the adjacent T 2  electrodes. As shown in  FIG. 11 , the order of the RX electrodes in a given column is reversed for each successive row. For example, the R 4  electrode adjacent to T 1  is at the bottom of row  1121 , whereas the R 4  electrode adjacent to T 2  is at the top of row  1122   
     Further, a group of fifth TX electrodes (T 5 ) is disposed in columns  1107 ,  1109 , and  1111  of the first row  1121 . Each of the T 5  electrodes is adjacent to eight RX electrodes R 9 -R 12 , R 13 -R 16 , R 1 -R 4 , and R 5 -R 8  disposed in columns  1106 ,  1108 ,  1110 , and  1112 , respectively, of row  1121 . Thus, when the T 5  electrodes are driven, the RX electrodes R 1 -R 16  may detect a unique capacitive coupling from the adjacent T 5  electrodes. Because none of the RX electrodes adjacent to the T 5  electrodes are reused or repeated, and because the RX electrodes R 5 -R 8  on the right-most edge (e.g., column  1112 ) of the T 5  group of electrodes is different than the RX electrodes R 9 -R 12  on the left-most edge (e.g., column  1106 ) of the T 5  group, each of the RX channels R 1 -R 16  will detect a unique capacitive coupling with adjacent T 5  electrodes. 
     As shown in  FIG. 11 , the configuration of RX electrodes in column  1108  is substantially different than the configuration of RX electrodes in column  1008  of  FIG. 10 . Specifically, rather than reuse the first four RX electrodes R 1 -R 4  at the start of the next TX group (e.g., as shown in  FIG. 10 ), the last four RX electrodes R 13 -R 16  are disposed, instead, in column  1108 . Further, a particular group of RX electrodes (such as the RX electrodes R 1 -R 4  in column  1102 ) may be reused (e.g., in column  1108 ) only after each of the remaining groups of RX electrodes has been disposed in the intervening columns (such as the RX electrodes R 5 - 58  and R 13 -R 16  in columns  1104  and  1106 , respectively). Thus, in some embodiments, the per-column grouping of RX electrodes (e.g., R 1 -R 4  followed by R 5 -R 8  followed by R 9 -R 12  followed by R 13 -R 16 ) may be repeated in this manner until the very last column of TX electrodes is reached (e.g., column  1117  in  FIG. 11 ). 
     Moreover, in the example of  FIG. 11 , there is an equal distribution of RX electrodes R 1 -R 16 . In other words, there is an equal number of each of the RX electrodes R 1 -R 16  evenly distributed across the sensor array. As a result, the background capacitances detected across the different RX channels will be balanced. For example, each of the RX channels may sense the same amount of background capacitance each time the sensor electrodes are scanned. 
       FIG. 12  shows a single-layer capacitive sensing array  1200  with relatively balanced capacitive background coupling, in accordance with some embodiments. In the example of  FIG. 12 , a plurality of sensor electrodes T 1 -T 12  and R 1 -R 16  are arranged in rows  1221 - 1224  and columns  1201 - 1217  in a single-layer or coplanar configuration. For purposes of discussion, the larger electrodes T 1 -T 12  are referred to as TX electrodes and the smaller electrodes R 1 -R 16  are referred to as RX electrodes. However, in actual implementations, any of the larger electrodes T 1 -T 12  may perform the functions of RX electrodes and any of the smaller electrodes R 1 -R 16  may perform the functions of TX electrodes. TX electrodes with the same electrode number (e.g., T 1 , T 2 , T 3 , etc.) may be coupled to the same TX channel and RX electrodes with the same electrode number (e.g., R 1 , R 2 , R 3 , etc.) may be coupled to the same RX channel. Thus, in the example of  FIG. 12 , the capacitive sensing array  1200  includes 12 different TX channels and 16 different RX channels. 
     In some embodiments, the TX electrodes (and RX electrodes) are arranged in localized groups. For example, a group of first TX electrodes (T 1 ) is disposed in columns  1201 ,  1203 , and  1205  of the first row  1221  of the array  1200 . As described above, the T 1  electrodes may be coupled to a first TX channel and may thus be driven at the same time (e.g., concurrently) when the first TX channel is activated during a scan of the capacitive sensing array  1200 . Each of the T 1  electrodes is adjacent to at least four RX electrodes R 1 -R 4 , R 5 -R 8 , and R 9 -R 12  disposed in columns  1202 ,  1204 , and  1206 , respectively, of row  1221 . Thus, when the first TX channel is activated, the RX electrodes R 1 -R 12  may detect a unique capacitive coupling from the adjacent T 1  electrodes. 
     A group of second TX electrodes (T 2 ) is disposed in columns  1201 ,  1203 , and  1205  of the second row  1222  of the array  1200 . The T 2  electrodes may be coupled to a second TX channel, and may thus be driven at the same time when the second TX channel is activated. Each of the T 2  electrodes is adjacent to at least four RX electrodes R 1 -R 4 , R 5 -R 8 , and R 9 -R 12  disposed in columns  1202 ,  1204 , and  1206 , respectively, of row  1222 . Thus, when the second TX channel is activated, the RX electrodes R 1 -R 12  may detect a unique capacitive coupling from the adjacent T 2  electrodes. As shown in  FIG. 12 , the order of the RX electrodes in a given column is reversed for each successive row. For example, the R 4  electrode adjacent to T 1  is at the bottom of row  1221 , whereas the R 4  electrode adjacent to T 2  is at the top of row  1222   
     Further, a group of fifth TX electrodes (T 5 ) is disposed in columns  1207 ,  1209 , and  1211  of the first row  1221 . Each of the T 5  electrodes is adjacent to eight RX electrodes R 9 -R 12 , R 13 -R 16 , R 1 -R 4 , and R 5 -R 8  disposed in columns  1206 ,  1208 ,  1210 , and  1212 , respectively, of row  1221 . Thus, when the T 5  electrodes are driven, the RX electrodes R 1 -R 16  may detect a unique capacitive coupling from the adjacent T 5  electrodes. Because none of the RX electrodes adjacent to the T 5  electrodes are reused or repeated, and because the RX electrodes R 5 -R 8  on the right-most edge (e.g., column  1212 ) of the T 5  group of electrodes is different than the RX electrodes R 9 -R 12  on the left-most edge (e.g., column  1206 ) of the T 5  group, each of the RX channels R 1 -R 16  will detect a unique capacitive coupling with adjacent T 5  electrodes. 
     In the example of  FIG. 12 , the per-column grouping of RX electrodes is similar to that of  FIG. 11 . In other words, a particular group of RX electrodes (such as the RX electrodes R 1 -R 4  in column  1202 ) may be reused (e.g., in column  1208 ) only after each of the remaining groups of RX electrodes has been disposed in the intervening columns (such as the RX electrodes R 5 - 58  and R 13 -R 16  in columns  1204  and  1206 , respectively). However, there is an even number ( 8 ) of columns of TX electrodes  1201 ,  1203 ,  1205 ,  1207 ,  1209 ,  1211 ,  1213 , and  1215 . More specifically, in contrast with  FIG. 11 , each of the last four groups of TX electrodes (T 9 -T 12 ) includes only two TX electrodes instead of the three. As a result, the last group of RX electrodes R 13 -R 16  is not reused or repeated in the sensor electrode configuration  1200 . 
     Although there is an unequal distribution of RX electrodes R 1 -R 16 , the capacitive background coupling remains relatively balanced in some embodiments. For example, the first twelve RX channels (coupled to RX electrodes R 1 -R 12 ) may sense twice the amount of background capacitance as the last four RX channels (coupled to RX electrodes R 13 -R 16 ). Aspects of the present disclosure recognize that the imbalance in capacitive background coupling here is still significantly less than the imbalance resulting from the sensor electrode configuration  1000  (e.g., where the first eight RX channels sense three times the amount of background capacitance as any of the last eight RX channels). 
       FIG. 13  is an illustrative flowchart depicting an example capacitive sensing operation  1300 , in accordance with some embodiments. With reference for example to  FIG. 1 , the operation  1300  may be performed by the processing system  110  to scan the array of sensing elements  121  for a presence of input objects. 
     The processing system may activate a first transmitter channel coupled to a first transmitter electrode, where the first transmitter electrode is disposed in a first row and a first column of a capacitive sensor array ( 1310 ). With reference for example to  FIGS. 9-12 , each transmitter electrode may be coupled to a particular TX channel. The processing system may activate the first transmitter channel by driving a sensing signal on the TX channel coupled to the first transmitter electrode. In some embodiments, a group of TX electrodes may be coupled to the same TX channel as the first TX electrode. Thus, by driving a sensing signal onto the TX channel, the processing system may activate one or more additional TX electrodes concurrently with the first TX electrode. 
     The processing system senses a capacitive coupling between the first transmitter electrode and a plurality of first receiver electrodes adjacent the first transmitter electrode when the first transmitter channel is activated, where the first receiver electrodes are disposed in the first row and a second column of the capacitive sensor array ( 1320 ). With reference for example to  FIGS. 9-12 , each of the first receiver electrodes may be coupled to a respective RX channel. In some embodiments, the RX channels may be reused or repeated for different TX groups (e.g., in a given row the array). More generally, assuming a maximum number (m) of TX electrodes in each TX group and a number (n) of RX electrodes disposed between each pair of TX electrodes in the sensor array, the total number of distinct RX channels in the sensor electrode configuration  1000  is equal to n+n*m. 
     The processing system may further activate a second transmitter channel coupled to a second transmitter electrode, where the second transmitter electrode is disposed in the first row and a third column of the capacitive sensor array ( 1330 ). With reference for example to  FIGS. 9-12 , the second transmitter electrode may be coupled to a different TX channel than the first transmitter electrode. The processing system may activate the second transmitter channel by driving a sensing signal on the TX channel coupled to the second transmitter electrode. In some embodiments, a group of TX electrodes may be coupled to the same TX channel as the second TX electrode. Thus, by driving a sensing signal onto the TX channel, the processing system may concurrently activate one or more TX electrodes in addition to the second TX electrode. 
     The processing system senses a capacitive coupling between the second transmitter electrode and a plurality of second receiver electrodes adjacent the second transmitter electrode when the second transmitter channel is activated, where the second receiver electrodes are disposed in the first row and a fourth column of the capacitive sensor array ( 1340 ). With reference for example to  FIGS. 9-12 , the second receiver electrodes may be coupled to the same RX channels as the first receiver electrodes. In other words, the second receiver electrodes may be reused or repeated to detect capacitive couplings with the second transmitter electrode. However, because each group of TX electrodes is coupled to a different TX channel, the RX channels may detect a unique capacitive coupling between the activated TX electrodes and adjacent RX electrodes in any portion of the array. 
     In some embodiments, the RX electrodes disposed on the left-most edge of the TX group (which includes all TX electrodes coupled to the second TX channel) may be coupled to different RX channels than the RX electrodes disposed on the right-most edge of the TX group, such as described with respect to  FIG. 10 . In some other embodiments, a particular group of RX electrodes (such as the RX electrodes R 1 -R 4  in column  1102  of  FIG. 11 ) may be reused (e.g., in column  1108 ) only after each of the remaining groups of RX electrodes has been disposed in the intervening columns, such as described with respect to  FIG. 11 . 
     In some embodiments, the processing system may further determine whether an input object is in contact with, or proximity of, the capacitive sensor array based on the capacitive coupling ( 1350 ). For example, an object in contact with (or close proximity of) the capacitive sensor array may cause changes in the capacitive coupling between local TX and RX electrodes. In some aspects, the processing system may sense the presence of one or more input objects using absolute capacitance sensing techniques. In some other aspects, the processing system may sense the presence of one or more input objects using transcapacitance sensing techniques. In some embodiments, the processing system may further correct for parasitic couplings between user inputs and routing traces (e.g. by linear corrections, iterative estimation, etc.). 
     Those of skill in the art will appreciate that information and signals may be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be referenced throughout the above description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof. 
     Further, those of skill in the art will appreciate that the various illustrative logical blocks, modules, circuits, and algorithm steps described in connection with the aspects disclosed herein may be implemented as electronic hardware, computer software, or combinations of both. To clearly illustrate this interchangeability of hardware and software, various illustrative components, blocks, modules, circuits, and steps have been described above generally in terms of their functionality. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the disclosure. 
     The methods, sequences or algorithms described in connection with the aspects disclosed herein may be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two. A software module may reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art. An exemplary storage medium is coupled to the processor such that the processor can read information from, and write information to, the storage medium. In the alternative, the storage medium may be integral to the processor. 
     In the foregoing specification, embodiments have been described with reference to specific examples thereof. It will, however, be evident that various modifications and changes may be made thereto without departing from the broader scope of the disclosure as set forth in the appended claims. The specification and drawings are, accordingly, to be regarded in an illustrative sense rather than a restrictive sense.