Method, input device, and computer-readable non-temporary storage medium

Abstract

To provide a detection system and a method which reduce or eliminate irradiated emission by using a code division multiplex (CDM) drive matrix with null total row sum.SOLUTION: A measured value corresponding to an input received on a detection area of an input device is acquired by steps of driving a first subset of a transmitter of the input device in response to a first part of a CDM drive matrix as a null total row matrix, of acquiring a first measure signal by a plurality of receivers, of driving a second subset of the transmitter in response to a second part of the CDM drive matrix, and of acquiring a second measure signal by the plurality of receives while including at least one common transmitter of the first subset and the second subset of the transmitter. An input image is sometimes generated based on the acquired measurement.SELECTED DRAWING: Figure 13

Description

[Technical Field]

[0001] The present disclosure generally provides systems and methods for input sensing using code division multiplexing (CDM). [Background technology]

[0002] Input devices including touch sensor devices (also commonly referred to as touchpads or proximity sensor devices) and fingerprint sensor devices are widely used in various electronic systems. Touch sensor devices typically include a sensing area, often defined by a surface, within which the touch sensor device determines the presence, position, force, and / or movement of one or more input objects. Touch sensor devices may be used to enable a user to provide user input for operating an electronic system. Fingerprint sensor devices also typically include a sensing area within which the fingerprint sensor device determines the presence, position, movement, and / or characteristics of a fingerprint or a portion of a fingerprint. Fingerprint sensor devices may be used for purposes related to user authentication or user recognition.

[0003] Touch and fingerprint sensor devices may thus be used to provide an interface to electronic systems. For example, touch and fingerprint sensor devices are often used as input devices for larger computer systems, such as opaque touchpads and fingerprint readers integrated inside notebook or desktop computers or as peripherals. Touch and fingerprint sensors are also often used in smaller computer systems, such as touch sensors integrated inside mobile devices like smartphones and tablets. Summary of the Invention

[0004] An embodiment provides a method for sensing an input using an input device. The method includes receiving an input at a sensing area of ​​the input device and acquiring measurements corresponding to the input using multiple receivers of the input device. Acquiring the measurements may include driving a first subset of transmitters of the input device according to a first portion of a CDM transmitter control, or drive, matrix, which is a row-sum-zero matrix, acquiring the first measurements using the multiple receivers, and driving a second subset of transmitters according to a second portion of the CDM drive matrix, acquiring the second measurements using the multiple receivers. The first and second subsets of transmitters include at least one common transmitter. The method may further include generating, by a processing system of the input device, an image of the input based on the acquired first and second measurements. Acquiring the measurements may further include driving a third subset of transmitters according to the CDM drive matrix and acquiring the third measurements using the multiple receivers. The third subset of transmitters includes at least one common transmitter with either the first or second subset of transmitters. Generating the image may include processing the first measurement, the second measurement, and the third measurement.

[0005] Another embodiment provides an input device for sensing a biometric object. The input device may include a surface corresponding to a sensing area configured to receive one or more inputs (e.g., one or more objects, such as one or more fingers), transmitters configured to be driven with transmitter signals, and a receiver configured to receive the measurement signals by driving a first subset of the transmitters according to a first portion of a CDM drive matrix, the CDM drive matrix being a row-to-zero matrix, to obtain first measurement signals at the receiver, and then driving a second subset of the transmitters according to a second portion of the CDM drive matrix, the first and second subsets of transmitters including at least one common transmitter, to obtain second measurement signals at the receiver. The input device may further include a processing system configured to generate an image of the one or more inputs based on the obtained first and second measurement signals.

[0006] Yet another embodiment provides a computer-readable non-transitory storage medium having processor-executable instructions stored thereon. The processor-executable instructions include instructions for performing input sensing using an input device. When executed by a processing system, the processor-executable instructions cause the processing system to perform a method including: driving a first subset of transmitters of the input device in accordance with a first portion of a CDM drive matrix, the CDM drive matrix being a row-sum-zero matrix; acquiring first measurement signals at a receiver; driving a second subset of transmitters in accordance with a second portion of the CDM drive matrix, the first and second subsets of transmitters including at least one common transmitter; and acquiring second measurement signals at the receiver, thereby acquiring measurement signals corresponding to one or more inputs received at a sensing area of ​​the input device via a receiver of the input device. The processor-executable instructions further enable the processing system to generate an image of the one or more inputs by processing the first measurement signals and the second measurement signals.

[0007] In one aspect, all drive-and-measure iterations for the first subset of transmitters are performed before any drive-and-measure iterations for the second subset of transmitters are performed.

[0008] Further embodiments provide a method of processing an input device having multiple receivers and multiple transmitters. The method may include receiving one or more inputs at a sensing area of ​​the input device, activating multiple transmitters, and acquiring measurement signals using the multiple transmitters while the transmitters are activated. Acquiring the measurement signals may include acquiring first measurement signals corresponding to the inputs using a first subset of the input device's multiple receivers, and then acquiring second measurement signals corresponding to the inputs using a second subset of the input device's multiple receivers, the second subset including at least one transmitter in common with the first subset. The method may further include determining a difference between the first and second measurement signals corresponding to the at least one common transmitter, and adjusting one of the first or second measurement signals based on the determined difference, e.g., to thereby remove a difference between noise detected in the first and second measurement signals.

[0009] Reference to the remaining portions of the specification, including the drawings and claims, will realize other features and advantages of the present disclosure. Further features and advantages of the present disclosure, as well as the structure and operation of various embodiments of the present disclosure, are described in detail below with reference to the accompanying drawings, in which like reference numbers indicate identical or functionally similar elements. [Brief explanation of the drawings]

[0010] The detailed description is set forth with reference to the accompanying drawings, in which: The use of like reference numbers in different instances in the description and drawings may indicate similar or similar items.

[0011] [Figure 1]FIG. 1 is a block diagram illustrating an exemplary input device according to one or more embodiments.

[0012] [Figure 2A] FIG. 2A is a block diagram illustrating a further exemplary input device according to some embodiments. [Figure 2B] FIG. 2B is a block diagram illustrating a further exemplary input device, according to some embodiments.

[0013] [Figure 3] FIG. 3 illustrates an orthogonal grid of transmitter and receiver electrodes for an input device according to one or more embodiments.

[0014] [Figure 4A] FIG. 4A illustrates an example of zero row sum CDM for radiated emissions mitigation according to one or more embodiments.

[0015] [Figure 4B] FIG. 4B illustrates an example of interleaved row-sum-zero CDM for radiated emissions mitigation according to one or more embodiments.

[0016] [Figure 5] FIG. 5 illustrates an example of an odd-dimensional matrix, according to one or more embodiments.

[0017] [Figure 6A] FIG. 6A illustrates an example of an odd-dimensional CDM7 matrix according to one or more embodiments.

[0018] [Figure 6B] FIG. 6B illustrates an example CDM matrix that includes three overlapping CDM matrices from FIG. 6A, according to one or more embodiments.

[0019] [Figure 6C] FIG. 6C illustrates an example of a seven-dimensional circulant matrix according to one or more embodiments.

[0020] [Figure 6D] FIG. 6D illustrates an example of an even-dimensional CDM8 matrix according to one or more embodiments.

[0021] [Figure 7] FIG. 7 shows the full (21×21) inverse of the matrix of FIG. 6B, according to one or more embodiments.

[0022] [Figure 8] FIG. 8 illustrates example image data deconvolved with a zero row sum CDM7 matrix in the presence of display noise for two fingers touching the screen of an input device, according to one embodiment.

[0023] [Figure 9] FIG. 9 illustrates an example of image data (FIG. 8) deconvolved with a zero row sum CDM7 matrix in the presence of display noise after undergoing a stitching and recombination process for two fingers touching the screen of an input device, according to one embodiment.

[0024] [Figure 10] FIG. 10 shows example image data (FIG. 9) deconvolved with a zero row sum CDM7 matrix in the presence of display noise for two fingers touching the screen of an input device after undergoing stitching and recombination processes and after removing common mode noise and artifacts, according to one embodiment.

[0025] [Figure 11] FIG. 11 shows data acquired with overlapping electrodes in two receiver drive steps and the results of a stitching process to correct for noise differences between the steps, according to one embodiment.

[0026] [Figure 12]FIG. 12 shows data acquired with two overlapping electrodes during two receiver drive steps and the results of a stitching process to correct for noise differences between the drive steps, according to one embodiment.

[0027] [Figure 13] FIG. 13 is a flowchart illustrating processing using lower-order row-sum-zero CDM, according to one embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0028] The following detailed description is exemplary in nature and is not intended to limit the disclosure or the application and uses of the disclosure. Furthermore, there is no intention to be bound by any expressed or implied theory presented in the preceding background, summary, and brief description of the figures or the following detailed description.

[0029] In one or more embodiments, input devices, including touch sensor devices and fingerprint sensor devices, use code division multiplexing (CDM) on transmitter signals driven to the transmitter electrodes to extend the signal level. In some embodiments, the order of the CDM corresponds to the amount of transmitters driven simultaneously, but is equal to the total number of transmitter electrodes, such that all transmitter electrodes are driven simultaneously for multiple display or sensing iterations. In some embodiments, lower-order CDM may be used when fewer transmitter electrodes are driven simultaneously. For example, separate portions or blocks of a larger CDM drive matrix may be used to drive separate or overlapping portions of the transmitter electrodes at different times. Lower-order CDM provides various advantages, including reduced peak power, reduced average power, reduced sensor self-heating, and reduced computational complexity. These advantages may be realized in a flexibly configurable manner to meet the desired power specifications of various implementations of touch sensor devices and fingerprint sensor devices.

[0030] FIG. 1 is a block diagram illustrating an example input device 100, according to one or more embodiments. The input device 100 may be configured to provide input to an electronic system (not shown for simplicity). As used herein, the phrases “electronic system” or “electronic device” broadly refer to any system capable of electronically processing information. Non-limiting examples of electronic systems include personal computers of all sizes and shapes, such as desktop computers, laptop computers, netbook computers, tablets, web browsers, e-readers, personal digital assistants (PDAs), and wearable computers (such as smart watches and activity tracker devices). Additional examples of electronic systems include composite input devices, such as a physical keyboard that includes the input device 100 and a separate joystick or key switches. Further examples of electronic systems include peripherals, such as a data input device (including a remote controller or mouse) and a data output device (including a display screen and printer). Other examples include remote terminals, kiosks, and video game devices (e.g., video game consoles, handheld game consoles, etc.). Other examples include communication devices (including mobile phones such as smartphones), media devices (including recorders, editors, players such as televisions, set-top boxes, music players, digital photo frames, and digital cameras), etc. Additionally, an electronic system or device may be a host or a slave to an input device.

[0031] The input device 100 may be implemented as a physical part of an electronic system or may be physically separate from the electronic system. The input device 100 may communicate with parts of the electronic system using one or more of a bus, a network, and other wired or wireless interconnections, as needed. Examples include an Inter-Integrated Circuit (IIC) interconnection. 2C), Serial Peripheral Interface (SPI), Personal System / 2 (PS / 2), Universal Serial Bus (USB), Bluetooth, radio frequency (RF), and Infrared Data Association (IrDA).

[0032] In one or more embodiments, the input device 100 includes one or more sensing elements for detecting user input. The input device 100 may include one or more sensors 105. The sensor 105 includes one or more sensing elements configured to sense input provided by one or more input objects in a sensing area. Examples of input objects include a finger, a stylus, and a hand. The sensing area encompasses any space within which the input device 100 can detect user input (e.g., user input provided by one or more input objects), such as above, around, within, and / or near the sensor 105. The size, shape, and / or location of the sensing area may vary from embodiment to embodiment depending on the actual implementation. In some embodiments, the sensing area extends in one or more directions from the surface of the input device 100 into space until the signal-to-noise ratio is insufficiently accurate for object detection. The distance the sensing area extends in a given direction may be on the order of less than a millimeter, on the order of millimeters, on the order of centimeters, or longer, in various embodiments. This distance may vary depending on the type of sensing technology used and / or the accuracy required. Thus, in some embodiments, detected inputs include non-contact with any surface of input device 100, contact with an input surface (e.g., touch surface and / or screen) of input device 100, contact with an input surface of input device 100 with the application of a certain amount of force or pressure, or a combination thereof. In various embodiments, the input surface may be provided as the surface of a sensor substrate having sensing elements disposed therein or on its surface. Alternatively, the input surface may be provided by a face sheet or other cover layer disposed over the sensing elements. In various embodiments, the input surface may be provided as one or more surfaces of a casing or housing of input device 100.

[0033] Input device 100 may use various sensing technologies to detect user input in a sensing area. Example sensing technologies include capacitive, elastic, resistive, inductive, magnetic, acoustic, ultrasonic, and / or optical sensing technologies. In some embodiments, input device 100 may use capacitive sensing technology to detect user input. For example, the sensing area may include one or more capacitive sensing elements (e.g., sensor electrodes) that create an electric field due to an applied voltage and / or current. Input device 100 may detect input based on changes in the capacitance of the sensing elements. For example, an object in contact with (or proximity to) the electric field may cause a voltage and / or current change in the sensing element. Such a change may be detected as a “signal” indicative of user input. Sensing elements may be arranged in an array or other regular or irregular pattern or other configuration to detect input at multiple points within the sensing area. In some implementations, separate sensing elements are ohmically shorted together to form a larger sensor electrode. In some other implementations, an electrically resistive sheet may be used, which may have a uniform electrical resistance.

[0034] Some capacitive sensing techniques may be based on “self-capacitance” (also referred to as “absolute capacitance”) and / or “mutual capacitance” (also referred to as “transcapacitance”). Absolute capacitive sensing detects changes in capacitive coupling between one or more sensing elements and a substantially grounded touching or nearby object. For example, an input object near one or more sensing elements alters the electric field near the sensing elements, changing the measured capacitive coupling between two or more sensor electrodes of the sensing elements. In some embodiments, the input device 100 may achieve absolute capacitive sensing by modulating a sensor electrode with respect to a reference electrode and detecting the capacitive coupling between the sensor electrode and the input object. The reference voltage may be substantially constant or may vary. In some aspects, the reference voltage may correspond to ground potential.

[0035] Transcapacitive (or transcapacitive or transverse capacitive) sensing detects changes in capacitive coupling between multiple sensor electrodes. In various embodiments, an input object in proximity to the sensor electrodes alters the electric field between the sensor electrodes, thereby changing the measured capacitive coupling. In some implementations, transcapacitive sensing works by detecting capacitive coupling between one or more transmitter sensor electrodes (also known as “transmitter electrodes” or “drive electrodes”) and one or more receiver sensor electrodes (also known as “receiver electrodes” or “pickup electrodes”). The transmitter sensor electrodes may be modulated with respect to a reference voltage to transmit the transmitter signal. The receiver sensor electrodes may be held substantially constant with respect to the reference voltage to facilitate reception of the resultant signal. The reference voltage may be, for example, a substantially constant voltage or a system ground. In some embodiments, both the transmitter and receiver sensor electrodes may be modulated. The transmitter electrodes are modulated with respect to the receiver electrodes to transmit the transmitter signal and to facilitate reception of the resultant signal. The resulting signal may include contributions corresponding to one or more transmitter signals and contributions corresponding to one or more environmental sources of interference (e.g., other electromagnetic signals). A sensor electrode may be a dedicated transmitter or receiver, or may be configured as both a transmitter and a receiver.

[0036] Some implementations of input device 100 are configured to provide images that span one, two, three, or higher spatial dimensions. Input device 100 may have different sensing resolutions from embodiment to embodiment, depending on factors such as the particular sensing technology and / or the scale of the information of interest. In some embodiments, the sensing resolution is determined by the physical arrangement of the array of sensing elements, where smaller sensing elements and / or a smaller pitch may be used to provide a higher sensing resolution.

[0037] The input device 100 may be implemented as a fingerprint sensor with a resolution high enough to capture the recognizable features of a fingerprint. In some implementations, the fingerprint sensor may have sufficient resolution to capture minutiae (e.g., including ridge endpoints and bifurcations), orientation fields (sometimes referred to as "ridge flow"), and / or ridge skeletons. These are sometimes referred to as Level 1 and Level 2 features, and in some embodiments, the sensor can reliably capture features at a resolution of at least 250 pixels per inch (ppi). In some implementations, the fingerprint sensor has sufficient resolution to capture higher-level features, such as pores or edge contours (e.g., the shape of the edges of individual ridges). These are sometimes referred to as Level 3 features, and in some embodiments, the sensor can reliably capture these higher-level features at a resolution of at least 750 pixels per inch (ppi).

[0038] In some embodiments, the fingerprint sensor is implemented as a placement sensor (also known as an "area" or "static" sensor) or a swipe sensor (also known as a "slide" or "sweep" sensor). In a placement sensor implementation, the sensor is configured to capture fingerprint input when a user's finger is held stationary over a sensing area. A placement sensor may include a two-dimensional array of sensing elements capable of capturing a desired portion of a fingerprint in a single frame. In a swipe sensor implementation, the sensor is configured to capture fingerprint input based on relative movement of the user's finger and the sensing area. A swipe sensor may include a linear or elongated two-dimensional array of sensing elements configured to capture multiple frames as the user's finger swipes over the sensing area. The multiple frames are then reconstructed to form an image of the fingerprint corresponding to the fingerprint input. In some implementations, the sensor is configured to capture both placement and swipe input.

[0039] In some embodiments, the fingerprint sensor is configured to capture less than the entire area of ​​a user's fingerprint in a single user input (referred to herein as a "partial" fingerprint sensor). Typically, the resulting partial area of ​​a fingerprint captured by a partial fingerprint sensor is sufficient for the system to perform fingerprint matching from a single fingerprint user input (e.g., a single fingerprint placement or a single fingerprint swipe). Some examples of imaging areas for partial placement sensors are 100 mm 2 In another exemplary embodiment, the partially positioned sensor includes an imaging area of ​​20 to 50 mm or smaller. 2 In some embodiments, the partial fingerprint sensor has an input surface the same size as the imaging area.

[0040] 1 for one or more embodiments, input device 100 includes a processing system 110. Processing system 110 may comprise part or all of one or more integrated circuits (ICs) and / or other circuitry components. Processing system 110 is coupled to sensor 105 and configured to detect input in a sensing area using sensing hardware of sensor 105.

[0041] The processing system 110 may include driver circuitry configured to apply sensed signals via sensing hardware of the input device 100 and / or receiver circuitry configured to receive result signals via the sensing hardware. For example, the processing system may be configured to apply transmitter signals to transmitter electrodes of the sensor 105 and / or receive detected result signals via receiver electrodes of the sensor 105.

[0042] The processing system 110 may include a computer-readable, non-transitory storage medium having processor-executable instructions (such as firmware code and / or software code) stored thereon. The processing system 110 may be implemented as a physical part of the sensor 105 or may be physically separate from the sensor 105. Additionally, the components constituting the processing system 110 may be co-located or physically separated from each other. For example, the input device 100 may be connected to a computing device as a peripheral, and the processing system 110 may include software (e.g., with associated firmware) configured to run on a central processing unit of the computing device and on one or more integrated circuits (ICs) separate from the central processing unit. As another example, the input device 100 may be physically integrated with a mobile device. The processing system 110 may include circuitry and firmware that are part of the mobile device's main processing unit. The processing system 110 may be dedicated to implementing the input device 100. Alternatively, the processing system 110 may perform other functions, such as operating a display screen or driving a haptic actuator.

[0043] The processing system 110 may activate the sensing elements of the sensor 105 of the input device 100 to generate an electronic signal indicative of input (or lack of input) at the sensing area. The processing system 110 may perform any suitable amount of processing on the electrical signal to generate information provided to the electronic system. For example, the processing system 110 may digitize analog electrical signals obtained from the sensor electrodes. As another example, the processing system 110 may perform filtering or other signal conditioning. As yet another example, the processing system 110 may subtract a baseline or perform other calculations so that the information reflects the difference between the electrical signal and a baseline. As yet another example, the processing system 110 may determine position information, recognize the input as a command, perform handwriting recognition, match a biological sample, etc.

[0044] The sensing area of ​​the input device 100 may overlap part or all of the active area of ​​the display device, for example, if the sensor 105 provides a touchscreen interface. The display device may be any suitable type of dynamic display capable of presenting a visual interface to a user, such as an inorganic light-emitting diode (LED) display, an organic light-emitting diode (OLED) display, a cathode ray tube (CRT), a liquid crystal display (LCD), a plasma display, an electroluminescence (EL) display, or other display technology. The display may be flexible or rigid, and may have a planar, curved, or other shape. The display may include a glass or plastic substrate for thin-film transistor (TFT) circuitry. The TFT circuitry may be used to address the display pixels to provide visual information and / or other functions. The display device may include a cover lens (sometimes called a "cover glass") disposed above the display circuitry and on the inner layers of the display module. The cover lens may also provide an input surface for the input device 100. Examples of materials for the cover lens include optically transparent amorphous materials such as chemically hardened glass and optically transparent crystalline materials such as sapphire. The input device 100 and the display device may share physical components. For example, some of the same electronic components may be used for both displaying visual information and sensing input by the input device 100, such as using one or more display electrodes for both display updating and input sensing. As another example, the display screen may be operated, in part or in whole, by a processing system 110 in communication with the input device.

[0045] 2A-2B are block diagrams illustrating additional input devices according to some embodiments. In FIG. 2A, input device 100 is shown including touch sensor 205a. According to some embodiments, touch sensor 205a is configured to detect position information of an input object within sensing area 220a. The input object may include a finger 240b or a stylus 240a, as shown in FIG. 2A. Sensing area 220a may have an input surface having an area larger than the input object. Touch sensor 205a may include an array of sensing elements with a resolution configured to detect the location of a touch on the input surface. Input device 100 may be further configured to detect the presence, force, and / or movement of the input object with touch sensor 205a. The input object may include one or more objects.

[0046] In FIG. 2B , input device 100 is shown to include fingerprint sensor 205b. Fingerprint sensor 205b is configured to capture a fingerprint from finger 240b. In one embodiment, sensor 205b is disposed directly beneath cover layer 212, which provides the input surface on which a fingerprint is placed or swiped across sensor 205b. Sensing area 220b may include an input surface having an area that is larger, smaller, or the same size as the entire fingerprint. Fingerprint sensor 205b may include an array of sensing elements with a resolution configured to detect variations in the surface of finger 240b. Fingerprint sensor 205b also has a higher resolution than touch sensor 205a of FIG. 2A .

[0047] FIG. 3 illustrates a 17×17 orthogonal grid of transmitter electrodes T1-T17 and receiver electrodes R1-R17 of an exemplary input device according to one or more embodiments. In FIG. 3, the input device is driven by a 17×17 drive matrix. It will be understood that the 17×17 grid is for illustrative purposes only, and various implementations of the input device can be any size having an even or odd number of electrodes (e.g., including 15×15, 15×27, 17×17, 17×27, 31×31, 16×16, 22×22, 56×96, 80×80, 88×116, 56×144, 72×80, and other electrode grid sizes). Furthermore, a grid in which the transmitter and receiver electrodes are arranged orthogonally in a bar and stripe configuration is used for illustrative purposes. However, it will be further understood that other exemplary implementations of capacitive input devices may use other arrangements of transmitter and receiver electrodes (including, for example, a single layer arrangement with integrated electrodes, a matrix arrangement where each pixel corresponds to an electrode plate, a diamond orthogonal arrangement, etc.) Although the examples discussed in this embodiment are described in the context of a capacitive input device, it will be understood that the principles described in this and other embodiments may also be applied to other types of input devices, such as acoustic or ultrasonic input devices, or other devices utilizing transmitters and receivers.

[0048] As shown in FIG. 3 , transmitter electrodes T1-T17 can be driven according to various CDM drive techniques or schemes. For example, in one CDM drive scheme, the CDM order is 17 (CDM17), and all of the transmitter electrodes T1-T17 are simultaneously driven with different encodings by each row of the CDM matrix with the same row sum over 17 iterations of imaging (corresponding to a 17×17 drive matrix). Because all of the transmitter electrodes T1-T17 are driven 17 times, this can result in relatively high peak power, average power, sensor self-heating, and computational complexity. The information captured by the CDM technique is then deconvolved or decoded using the inverse (for drive matrices with nonzero row sums) or transpose (for drive matrices with zero row sums) of the drive matrix to obtain an image corresponding to the input.

[0049] Certain sensor applications, such as automotive subsystems, may have a very strict set of requirements for electromagnetic radiated emissions that must not be exceeded. One such standard is CISPR25 (International Special Committee on Radio Interference). The CISPR25 standard includes upper limits on emissions over frequency and has upper limits for three measurements (peak, quasi-peak, and average) over frequency, measured as a spectrum analysis. In some embodiments, capacitive touch sensing systems used in vehicles may be inherently radiating because the touch sensing system detects fingers by varying the voltage on sensor electrodes and measuring the change in capacitance at those electrodes. Every electrode may act as an antenna and may emit radiation. When a CDM scheme results in an increase in signal-to-noise ratio, radiated emissions may also increase depending on the row sum of the transmitter control / drive CDM matrix.

[0050] In one embodiment, a zero-row-sum driving matrix is ​​used to drive the sensor electrodes, enabling deconvolution of raw measurements to recover the original signal at each electrode within any constant. A zero-row-sum driving matrix can be conveniently configured to provide a zero-amplitude baseline in a 2D image. A zero-row-sum matrix has the desirable property of causing the sum of emissions from the active (driven) set of transmitter electrodes ("transmitters") to be zero in a CDM driving pattern. This means that, as shown in FIGS. 4A and 4B, emitted radiation from half of the active transmitters is emitted or coupled 180° out of phase with the other half of the active transmitters, resulting in zero or negligible net radiated emissions. FIG. 4A shows an example of zero-row-sum CDM emission radiation. In particular, one driving iteration is shown using a zero-row-sum CDM matrix to drive seven consecutive subsets of transmitter electrodes (the top seven transmitter electrodes in FIG. 4A). For the particular drive iteration shown, the middle (fourth) electrode of the seven driven electrodes is not transmitting (0). Figure 4B shows an example of an interleaved row-sum-zero CDM using a CDM7 matrix to drive non-contiguous transmitter electrodes, as described in detail below. In the particular interleaved drive iteration shown in Figure 4B, all other transmitter electrodes are driven using CDM7, and the undriven transmitter electrode (the ninth from the top in the example) may be driven in the immediately following CDM drive iteration.

[0051] A class of matrices has an elegant property:

number

[0052] Reducing radiated emissions can be useful for simultaneous touch sensing and for application to automotive radiated emissions specifications / standards. With a square wave waveform, there may be an infinite number of harmonics, many of which may fall within the frequency band where radiated emissions limits exist. Using a zero row sum driving matrix effectively reduces these harmonics. Even with sinusoidal sensing, reducing emissions at a single frequency may be required, depending on specific requirements and future international specification amendments.

[0053] In one embodiment, the CDM driving matrix M has three properties. 1. The elements of a matrix are in the set {-1, 0, +1}. 2. The sum of each row is 0. That is,

number

number

[0054] Examples of CDM driving matrices of dimensions 3, 5, and 7 are shown in Figure 5. These odd row-to-zero matrices have the additional property that the transpose of M is the positive or negative version of matrix M depending on the dimension d. That is, if (d-1) / 2 is even, then MT =M, and if (d-1) / 2 is odd, then M T =-M.

[0055] When the right-hand side of Equation 1 is averaged over all pixels (index i), it equals zero. This property indicates that the resulting value of each CDM block averages (and sums) to zero. Therefore, when multiple CDM blocks are required for larger sensors, the deconvolved complete profile of an object touching the sensor may have discontinuities. Furthermore, because each column of CDM blocks averages to zero after deconvolution, there is one free parameter to be determined per CDM block per receiver to reconstruct the original image. As an example, for three CDM blocks and 27 physical receivers, there may be 3 × 27 = 81 free parameters to be determined. Furthermore, in situations where the transmitter of a small CDM block is covered by more than one object (e.g., a finger), it may be difficult to determine the original signal, making it difficult to reconstruct or reproduce the original image in various situations. Therefore, it is desirable to reduce the number of free parameters to be determined.

[0056] According to one embodiment, multiple overlapping CDM blocks are used, where multiple overlapping CDM blocks are "stitched" together to form a larger CDM driving matrix. Such an embodiment advantageously reduces the number of free parameters to be determined, improving the efficiency of reconstruction of the original detected image, and retaining the benefits of zero-row-sum CDM while reducing or eliminating negative side effects of artifacts such as baseline error and low ground mass (LGM) effects, improving large object recognition, removing display noise, etc. LGM effects may manifest, for example, as distortion of the large object signal or the presence of spurious negative signals at the intersection of the touched receiver and transmitter.

[0057] For example, in one embodiment, each constituent CDM block forming a larger CDM block overlaps with at least one of the other constituent CDM blocks. That is, each constituent CDM block drives at least one transmitter that is in common with another constituent CDM block. In one embodiment, any number of constituent CDM blocks may be used, where each constituent CDM block has at least one transmitter in common with (driven by) one of the other constituent CDM blocks.

[0058] According to one embodiment, a method of input sensing using an input device driven by such a zero-row-sum CDM matrix may include receiving an input at a sensing area of ​​the input device and acquiring measurement signals corresponding to the input using multiple receivers of the input device. Here, receiving the measurement signals may include driving a first subset of transmitters of the input device in accordance with a first portion of the CDM drive matrix and acquiring first measurement signals with the multiple receivers, and driving a second subset of transmitters in accordance with a second portion of the CDM drive matrix, the first and second subsets of transmitters including at least one common transmitter, and acquiring second measurement signals with the multiple receivers. In one aspect, during each drive step or iteration, the measurement signals acquired or acquired by the multiple receivers are acquired or acquired simultaneously upon driving the corresponding subset of transmitters.

[0059] As an example, FIG. 6A shows an example of a CDM7 block 600 with a row sum of zero. FIG. 6B also shows an example of a 15×21 CDM transmitter control matrix (or drive matrix) 610 including three of the overlapping CDM7 blocks 600 of FIG. 6A (shown as Block 1, Block 2, and Block 3 in FIG. 6B) for a touch sensor including 15 transmitter rows. Successive rows of the drive matrix represent successive drive iterations or periods in time, and columns indicate polarity (+1 or −1) or no transmission (0) for each transmitter. A touch sensor can include any number of receiver rows, such as 17 rows of receivers (15×17), 21 rows of receivers (15×21), or 27 rows of receivers (15×27), etc. As shown in Figure 6B, consecutive CDM blocks 1 and 2 overlap at transmitter electrodes 5, 6, and 7, and consecutive CDM blocks 2 and 3 overlap at transmitter electrodes 9, 10, and 11. It should be understood that multiple blocks may overlap at different transmitters or at fewer or more transmitters, and may apply to any arrangement of columns or rows.

[0060] In some embodiments, other types of matrices may be used that have the same CDM driving matrix properties as those described above, such as circulant matrices or even-dimensional matrices. For example, a zero-row CDM driving matrix may include a circulant matrix, an odd-dimensional matrix, or an even-dimensional matrix. Figure 6C illustrates an example of a seven-dimensional circulant matrix, according to one or more embodiments. Figure 6D illustrates an example of an even-dimensional CDM matrix, according to one or more embodiments.

[0061] Advantages of using a CDM matrix to drive electrodes include an increase in the signal-to-noise ratio (SNR) by approximately the square root of the CDM order, e.g., an improvement by the square root of 7 for CDM7. Advantages of using a zero-row sum CDM matrix further include reduced radiated emissions, particularly when used in transcapacitive touch sensing situations. According to an embodiment, higher order CDM matrices may be used to span longer distances, and / or smaller CDM matrices may be extended to span longer distances (e.g., driving non-contiguous transmitters in an interleaved manner, such as driving every other transmitter over the span of the CDM matrix, or every third transmitter over the span of the CDM).

[0062] Certain embodiments and advantages are now illustrated in conjunction with the drawings. Figure 8 illustrates example transformer capacitance image data deconvolved with a zero row sum CDM7 matrix for two fingers on a touch sensor with 15 transmitter rows and 27 receiver columns, acquired with the CDM drive matrix 610 of Figure 6B (which includes three overlapping CDM7 matrices), according to one or more embodiments. In an embodiment with 27 receivers, the three deconvolved CDM blocks of the 2D image are: Trans = (obj.cdmMatrixInvFull*transConvolved) / obj.cdmOrder is obtained by applying This means that in this embodiment, (matrix 21x27) = (matrix 21x21)*(matrix 21x27) / cmdOrder where cdmOrder = 7 This is a type of matrix operation. FIG. 7 is a full inverse matrix 700 (cdmMatrixInvFull) of the CDM drive matrix 610 shown in FIG. 6B , showing a 21×27 transconvolved matrix (transConvolved) corresponding to measurements acquired by 27 receiver electrodes over 21 transmitter drive iterations of the CDM drive matrix (e.g., each row of the CDM drive matrix 610 corresponds to a drive iteration in which all (active) receiver electrodes simultaneously sense a signal). The peaks reflect the finger shape and position, and subsequent Image Frame Processing (IFP) can be used to classify and process the image to obtain the desired image information. In one embodiment, a stitching and recombination process may be performed to obtain the entire image. For example, a process may be performed to stitch and recombine multiple CDM blocks together to obtain a single column of data per physical receiver. In the particular example used, stitching and recombination is performed to obtain a 15×27 image (corresponding to the 15 transmitter electrodes and 27 receiver electrodes in this example). In one embodiment, stitching and recombination can be accomplished as follows for this particular example (in Matlab® notation): % Matching / Stitching % Shared between block 1 and block 2 % Calculate the difference between data from the same physical transmitter dd1 = trans(6,:) - trans(9,:); (% index(6,9) corresponding to measurement time) dd2 = trans(7,:) - trans(10,:); dd3 = trans(5,:) - trans(8,:); dd = (dd1+dd2+dd3) / 3; % get the average % Shift entire block 1 trans(1:7,:) = trans(1:7,:) - repmat(dd,7,1); % Shared between block 2 and block 3 % Calculate the difference between data from the same physical transmitter dd1 = trans(13,:) - trans(16,:); dd2 = trans(12,:) - trans(15,:); dd3 = trans(14,:) - trans(17,:); dd = (dd1+dd2+dd3) / 3; % Shift entire block 3 trans(15:21,:) = trans(15:21,:) + repmat(dd,7,1); % Recombine 21x27 into the final 15x27, removing redundant data trans = [trans(1:7,:); trans(11,:); trans(end-6:end,:)]; % This recombination can be done in other ways % You end up with one column of data per receiver

[0063] FIG. 9 illustrates an example of image data (from FIG. 8) deconvolved with a zero-row-sum CDM7 driving matrix 610 for two fingers touching the screen of an input device after stitching and recombination, in the presence of display noise, according to one embodiment. As can be seen, after stitching, in FIG. 9, the entire "touched" column / receiver moves with the artifact or noise of a single common-mode zero-row-sum CDM, and the CDM blocks are no longer independent. For the particular "stitch" used in this example, the column shift is the average of the data in the columns of CDM block 2. It should be noted that the finger on the left touches the second CDM block, but the finger on the right does not, so no shift occurs on the right side.

[0064] For example, image processing algorithms may be performed to remove common-mode artifacts / noise and clean up the overall image. Figure 10 shows an example of zero-row-sum CDM7 deconvolved image data (from Figure 9) of two fingers touching the screen of an input device in the presence of display noise after stitching and recombination, after common-mode noise and artifact removal, according to one embodiment. In Figure 10, the fingers, LGM artifacts, etc. are clearly distinguished. In this example, IFP processing algorithms may be performed as needed (e.g., to correct the LGM if necessary, classify objects, etc.) so that the IFP can classify and report the two peaks as two fingers.

[0065] A mathematical analysis of stitching, according to one embodiment, is provided below.

[0066] As an example, consider two order N zero-row sum CDM blocks A and B. After being deconvolved, the measurement data for each transmitter is

number

number

[0067] It should be noted that the distribution of γ is different from the distributions of α and β, but the weights are the same. That is, there is no vector space that represents the display noise. Now, for simplicity, we use

number

[0068] Data reported after CDM deconvolution are

number

[0069] When there is a shared transmitter between two blocks of CDM and the difference between the data reported for the same transmitter in the two CDM blocks is calculated, the "finger" signals are cancelled out,

number

[0070] Since there are two different noise instances in the two blocks, the noise does not cancel, but since the difference between the two noise instances is still in the same vector space, i.e., still proportional to W, the delta can be added to any other transmitter and the noise reduction algorithm can still be performed in the same way.

[0071] Adding delta to every row in the second DCM block B (to shift the whole block) gives

number

[0072] Verification shows that, compared to block A, after noise removal there can be only one common vector A to be determined for both blocks, i.e. one value per receiver for the whole frame (and no longer per CDM block). The existence of only one common vector A is an easier problem to solve, which also allows for more powerful algorithms to be used.

[0073] Below is an example of Matlab® code for stitching, according to one embodiment: clear all; % Assume CDM5 with two CDM blocks overlapping by one row CDM = [0 -1 1 -1 1 ; -1 0 1 1 -1; 1 1 0 -1 -1; -1 1 -1 0 1; 1 -1 -1 1 0]; order = 5; assert(all(all(CDM * CDM' + ones(order) == order*eye(order)))) w = 1 + (1:10) / 10; % noise weight sigma = 10; rng(1) % Physical Background Capacity base1 = 10*rand(5,10); base2 = 10*rand(5,10); base2(1,:) = base1(5,:); % same signal r = sigma * (randn(5,1)); temp1 = base1 + r*w; % Display noise entity r = sigma * (randn(5,1)); temp2 = base2 + r*w; % Display noise entity a = (CDM' / order) * CDM * temp1 + 2048; % Row sums are zero, remove the mean b = (CDM' / order) * CDM * temp2 + 2048; % Row sums are zero, remove the mean % Force matching: last transmitter of CDM block A and first transmitter of CDM block B (same transmitter) db = a(5,:) - b(1,:); % difference dB = 1 * repmat(db,5,1); bp = b + dB; % apply the difference to the whole block B base = [a; bp(2:end,:)]; % Generate the first frame to be recombined and passed to the IFP r = sigma * (randn(5,1)); temp1 = base1 + r*w; % New display noise entity r = sigma * (randn(5,1)); temp2 = base2 + r*w; % New display noise entity injectedDelta = 10 *(rand(7,7) - 0.5); temp1(2:5,3:9) = temp1(2:5,3:9) + injectedDelta(1:4,:); a = (CDM' / order) * CDM * temp1 + 2048; % Row sums are zero, remove the mean temp2(1:4,3:9) = temp2(1:4,3:9) + injectedDelta(4:7,:); b = (CDM' / order) * CDM * temp2 + 2048; % Row sums are zero, remove the mean % Force matching: last transmitter of CDM block A and first transmitter of CDM block B (same transmitter) db = a(5,:) - b(1,:); % difference dB = 1 * repmat(db,5,1); bp = b + dB; % apply the difference to the whole block B raw = [a; bp(2:end,:)]; % Generate a second frame to be recombined and passed to the IFP %%% IFP starts here (it receives normal frames) delta = raw - base; % Calculate the delta image W = repmat(w,9,1); % Remove display noise, assume first (left) transmitter is untouched deltaNew = delta. / W; col = repmat(deltaNew(:,1),1,10); deltaNew = (deltaNew - col).*W row = repmat(deltaNew(1,:),9,1); % Fix minimum, assume first (top) receiver is untouched deltaNew = (deltaNew - row) % Correction confirmation error = deltaNew(2:8,3:9) - injectedDelta assert(all(all(error < 1e-8)))

[0074] In some embodiments, it may be desirable to operate an input device to sense with a reduced set of receivers of a sensing element, e.g., to reduce cost. For example, it may be desirable to sense with a first subset of the full set of receivers in one sensing iteration and with the remaining subsets of receivers in one or more subsequent sensing iterations. In such a multiplexed sensing scheme, data acquired by multiple disjoint sensing blocks (e.g., subsets of receivers) may be used to form a single image. As an example, for a 12-receiver electrode input device, the transmitter electrode may be activated in a first sensing iteration, receiver electrodes 1-6 may be activated, and receiver electrodes 7-12 may be activated in a second sensing iteration. Images from the two sensing iterations may be combined to form an overall image. However, such multiplexed sensing may have drawbacks in the presence of noise. For example, when common-mode noise is introduced into the data (e.g., by a display), it becomes difficult to remove the noise because there are different entities in different sensing iterations (multiplexes), which results in more free parameters to be determined and fewer electrodes participating in each sensing iteration (multiplex) to distinguish the signal from the noise. Because different sensing blocks are usually disjoint and different noise entities may be present in the corrected data for each block, the data from each sensing iteration (multiplex) needs to be cleaned separately. This can be difficult because the number of electrodes in each block is reduced, which reduces the ability to distinguish the signal (e.g., finger touch) from the noise.

[0075] According to certain embodiments, as described in detail below, one or more overlapping electrodes are used between each sensing iteration (multiplexing) to convert "multiplexed" data to "non-multiplexed" data, even in the presence of common-mode noise. By overlapping receiver blocks so that they share one or more sensing elements or receiver electrodes and performing a stitching process, the problem of differential noise is advantageously addressed at minimal cost. This advantageously eliminates the underlying problem and allows algorithms developed for non-multiplexed sensors to be used. The embodiments herein are useful for a variety of sensing schemes, including one-dimensional absolute sensing and two-dimensional trans-capacitive sensing schemes.

[0076] In one embodiment, a method for operating an input device having multiple receivers and multiple transmitters in a multiplexed manner may include receiving an input at a sensing area of ​​the input device and driving the multiple transmitters. Driving the transmitters may include one of applying a potential or a current to the transmitters. When the transmitters are driven, the method further includes acquiring measurement signals over two or more receiver driving steps or sensing iterations, where a subset of the full set of receivers is used or activated in each driving step or sensing iteration, each subset of receivers including at least one receiver in common with the previous subset. For example, a first measurement signal corresponding to the input may be acquired using a first subset of the input device's multiple receivers during a first driving step, followed by a second measurement signal corresponding to the input during a second driving step using a second subset of the input device's multiple receivers, where the second subset includes at least one receiver in common with the first subset. A difference between the first measurement signal and the second measurement signal corresponding to the at least one common receiver may be determined. One of the first measurement signal and the second measurement signal may be adjusted based on the determined difference to generate a noise-corrected measurement signal. In one aspect, during each driving step, the multiple receivers used or activated in that step are used or activated simultaneously.

[0077] FIG. 11 shows an example of data acquired with one receiver electrode overlapping a set of eleven receiver electrodes in two receiver drive steps, or sensing iterations, according to one embodiment. Receiver electrodes 1-6 are activated to acquire a first set of measurement signals in a first sensing iteration ("left multiplexing" in FIG. 11 ), and receiver electrodes 6-11 are activated to acquire a second set of measurement signals in a second sensing iteration ("right multiplexing" in FIG. 11 ), where receiver electrode 6 is common between the sensing iterations. As can be seen in this example, in the presence of noise, the time difference between the first and second sensing iterations, as evidenced by the difference in values ​​for the common receiver (e.g., electrode 6), may result in a detectable noise difference component in the measurements (e.g., noise may vary over time). In one embodiment, the difference in values ​​between the iterations for the common receiver may be used to determine the amount to shift the first set of measurement signals or the second set of measurement signals to remove the noise difference component between the sensing iterations.

[0078] In one embodiment, the process of determining the noise difference component and correcting the set of measurements for the two measurement iterations may be performed according to:

number

number

[0079] Usually, N (2) =N (1) +1, but here instead,

number

number

number

number

[0080] 11 further illustrates the results of a stitching or shifting process that corrects for noise differences between sensing steps, according to one embodiment. As shown, for electrode i=N (2) The data for N = electrodes 6 to 11 are shifted to correct for noise differences ("shifted right multiplex" in Figure 11).

[0081] When there is more than one common electrode and only one noise component, multiple Δs can be calculated and averaged. Furthermore, when the noise contains multiple components that are not linearly dependent on the common electrode, "multiple component" stitching may be performed.

[0082] FIG. 12 shows an example of data acquired from two overlapping sets of eleven receiver electrodes in two receiver drive steps, or sensing iterations, according to one embodiment. Receiver electrodes 1-6 are activated to acquire a first set of measurement signals in a first sensing iteration (the "left multiplex" in FIG. 12 ), and receiver electrodes 5-11 are activated to acquire a second set of measurement signals in a second sensing iteration (the "right multiplex" in FIG. 12 ), where receiver electrodes 5 and 6 are common between the sensing iterations. As can be seen in this example, in the presence of noise, the time difference between the first and second sensing iterations may result in a noise difference component (e.g., noise may vary over time), as evidenced by the difference in values ​​for the common receivers (e.g., electrodes 5 and 6). In one embodiment, the difference in values ​​for the common receivers may be used to determine an amount to shift the first set of measurement signals or the second set of measurement signals to remove the noise difference component between the sensing iterations. 12 further illustrates the results of a stitching or shifting process to correct for noise differences between sensing iterations where two electrodes are common, according to one embodiment. As shown, the data for electrodes 5 through 11 are shifted to correct for noise differences ("shifted right multiplexing" in FIG. 12).

[0083] FIG. 13 is a flowchart illustrating an exemplary process for sensing input with an input device using CDM, according to one embodiment. At stage 1001, input, such as a biometric object or object (e.g., one or more fingers) or stylus, is received in a sensing area of ​​the input device. At stage 1002, imaging is performed by the input device using CDM (e.g., using a CDM drive matrix including overlapping constituent CDM blocks in one or more transmitters, as described herein). The imaging performed may include, for example, a processing system deconvolving or decoding raw information acquired using CDM techniques. At stage 1003, the detected image may optionally be further processed, if appropriate, for example, using IFP techniques. At stage 1004, various functions (such as touch sensing, navigation functions, authentication, etc.) may be performed by the processing system based on the detected and / or processed image.

[0084] Various embodiments herein are useful for square wave sensing, sine wave sensing, or sensing of any modulated / shaped pattern.

[0085] Although the examples discussed above have been provided in the context of capacitive input devices, the principles described herein may also be applied to other types of input devices, such as acoustic or ultrasonic input devices that also use transmitters and receivers. For example, the transmitters of an acoustic or ultrasonic input device may also be driven over multiple iterations using overlapping lower-order CDM techniques such as those described herein.

[0086] U.S. Patent Application No. 15 / 720,817, filed September 29, 2017, and U.S. Patent Application No. 16 / 132,773, filed September 17, 2018, which are incorporated herein by reference, disclose various aspects of input sensing using a CDM drive matrix.

[0087] All references cited in this specification, including publications, patent applications, and patents, are hereby incorporated by reference and are incorporated in their entireties into this disclosure to the same extent as if each reference was individually and specifically indicated to be incorporated by reference.

[0088] In the context of describing the invention (particularly in the context of the claims below), the terms "a," "one," "the," "said," "at least one," and similar terms, when used, should be interpreted to cover both the singular and the plural, unless expressly stated otherwise herein or clearly contradicted by context. Unless expressly stated otherwise herein or clearly contradicted by context, the term "at least one" followed by a list of one or more items (e.g., "at least one of A and B") should be interpreted as a single item (A or B) selected from the list, or a combination of two or more of the listed items (A and B). The terms "comprising," "having," "including," and "containing" should be interpreted as open-ended terms (i.e., meaning "including, but not limited to"), unless expressly stated otherwise. Ranges of values ​​recited herein are merely intended as a shorthand method of referring individually to each separate value falling within the range, unless the specification expressly states otherwise. Each individual value is incorporated into the specification as if it were individually listed herein. All methods described herein may be performed in any suitable order unless otherwise indicated in the specification or otherwise clearly contradicted by context. Any and all examples used, or exemplary language used herein (e.g., "such as"), is intended merely to further clarify the invention and does not pose a limitation on the scope of the invention unless otherwise asserted. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the invention.

[0089] Illustrative embodiments have been described herein. Variations of those embodiments will be apparent to those skilled in the art upon reading the foregoing description. The inventors expect that such variations will be utilized by those skilled in the art. The inventors also intend that the invention be practiced otherwise than as specifically described herein. Accordingly, this invention includes all modifications and equivalents of the elements recited in the claims appended hereto as permitted by applicable law. Moreover, all possible combinations of the elements described above in their various variations are encompassed within the invention unless expressly stated otherwise in the specification or clearly contradicted by context.

Claims

1. 1. A method of operating an input device having multiple receivers and multiple transmitters, comprising: receiving an input at a sensing area of ​​the input device; Driving the plurality of transmitters; acquiring first measurement signals corresponding to the input using a first subset of the plurality of receivers of the input device; Then, acquiring a second measurement signal corresponding to the input using a second subset of the plurality of receivers of the input device, the second subset including at least one receiver in common with the first subset; determining a difference between the first and second measurement signals corresponding to the at least one common receiver; adjusting the first measurement signal or the second measurement signal based on the determined difference; Contains method.

2. the input device comprises a transcapacitive input device, the plurality of transmitters comprises transmitter electrodes, and the plurality of receivers comprises receiver electrodes; The method of claim 1.

3. determining the difference includes subtracting a value of the first measurement signal corresponding to the at least one common receiver from a value of the second measurement signal corresponding to the at least one common receiver to determine a noise difference component. The method of claim 1.

4. the first subset of receivers and the second subset of receivers include more than one common receiver; determining the difference includes subtracting values ​​of the first measurement signal corresponding to one or more of the one or more common receivers from values ​​of the second measurement signal corresponding to one or more of the one or more common receivers to determine a noise difference component. The method of claim 1.

5. It is an input device for sensing objects, a surface corresponding to a sensing area configured to receive an input; a plurality of transmitters configured to be driven by transmitter signals; Multiple receivers, obtaining a first measurement signal corresponding to the input using a first subset of the plurality of receivers; then acquiring a second measurement signal corresponding to the input using a second subset of the plurality of receivers of the input device, the second subset including at least one receiver in common with the first subset; determining a difference between the first and second measurement signals corresponding to the at least one common receiver; adjusting the first measurement signal or the second measurement signal based on the determined difference. a plurality of receivers configured to acquire measurement signals corresponding to the inputs by Equipped with Input devices.

6. determining the difference includes subtracting a value of the first measurement signal corresponding to the at least one common receiver from a value of the second measurement signal corresponding to the at least one common receiver to determine a noise difference component.

6. An input device according to claim 5.

7. the first subset of receivers and the second subset of receivers include more than one common receiver; determining the difference includes subtracting values ​​of the first measurement signal corresponding to one or more of the one or more common receivers from values ​​of the second measurement signal corresponding to one or more of the one or more common receivers to determine a noise difference component.

6. An input device according to claim 5.

8. 1. A computer-readable non-transitory storage medium having stored thereon processor-executable instructions for performing input sensing using an input device, the computer-readable non-transitory storage medium comprising: The processor-executable instructions, when executed by a processing system, cause the processing system to: receiving an input at a sensing area of ​​the input device; Driving the plurality of transmitters; acquiring first measurement signals corresponding to the input using a first subset of the plurality of receivers of the input device; Then, acquiring a second measurement signal corresponding to the input using a second subset of the plurality of receivers of the input device, the second subset including at least one receiver in common with the first subset; determining a difference between the first and second measurement signals corresponding to the at least one common receiver; adjusting the first measurement signal or the second measurement signal based on the determined difference; enabling a method including A computer-readable non-transitory storage medium.

9. determining the difference includes subtracting values ​​of the first measurement signal corresponding to the at least one common receiver from values ​​of the second measurement signal corresponding to the at least one common receiver to determine a noise difference component. The computer-readable non-transitory storage medium of claim 8.

10. the first subset of receivers and the second subset of receivers include more than one common receiver; determining the difference includes subtracting values ​​of the first measurement signal corresponding to one or more of the one or more common receivers from values ​​of the second measurement signal corresponding to one or more of the one or more common receivers to determine a noise difference component. The computer-readable non-transitory storage medium of claim 8.

Images