Correcting touch interference for active pen

Abstract

To provide a method and system for capacitive sensing, configured to improve performance of a capacitive imaging sensor when used with an active pen in the presence of a touch.SOLUTION: A method of capacitive sensing includes: obtaining a capacitive touch profile from multiple receiver electrodes disposed in a sensing region of an input device; obtaining an active pen profile, different from the capacitive touch profile, from the multiple receiver electrodes; adjusting, using the capacitive touch profile, the active pen profile to obtain a corrected active pen profile; and determining a position of an active pen in the sensing region, using the corrected active pen profile.SELECTED DRAWING: Figure 7

Description

[Technical Field]

[0001] This application is a direct response to U.S. Patent Application No. 63 / 224,368, filed on 21 July 2021, and claims priority to U.S. Patent Application No. 63 / 224,368. U.S. Patent Application No. 63 / 224,368 is incorporated herein by reference.

[0002] The embodiments described relate generally to electronic devices, and more specifically to improving the performance of capacitive imaging sensors when used with an active pen in the presence of touch. [Background technology]

[0003] Input devices, including proximity sensors (e.g., touchpads or touch sensor devices), are widely used in various electronic systems. A proximity sensor typically has a detection area, often demarcated by a surface, that identifies the presence, location, and / or movement of one or more input objects. Proximity sensors can be used to provide an interface to an electronic system. For example, proximity sensors are often used as input devices in larger computing systems (e.g., opaque touchpads built into or provided as peripherals in netbooks or desktop computers). They are also frequently used in smaller computing systems (e.g., touchscreens built into mobile phones).

[0004] Proximity sensor devices use one or more electrical techniques, such as capacitive sensing techniques, to determine the presence, position, and / or movement of an input object. Proximity sensor devices often use an array of sensor electrodes arranged in a sensor pattern to detect the presence, position, and / or movement of an input object.

[0005] The input object may be a finger, an active pen, or the like. Multiple input objects may be used simultaneously with the proximity sensor device. For example, a finger or palm may be placed on the surface of the proximity sensor device while input is being supplied using an active pen. The presence of a finger or palm may cause touch interference, which can degrade the input provided by the active pen.

[0006] Therefore, there is a need for methods and systems to address touch interference. [Overview of the project]

[0007] Overall, in one aspect, one or more embodiments relate to a method for capacitive detection. The method includes obtaining a capacitive touch profile from a plurality of receiver electrodes provided in a detection area of ​​an input device, and obtaining an active pen profile from the plurality of receiver electrodes that is different from the capacitive touch profile. The method also includes adjusting the active pen profile using the capacitive touch profile to obtain a corrected active pen profile, and using the corrected active pen profile to determine the position of the active pen in the detection area.

[0008] In other embodiments, one or more embodiments relate to an input device including a plurality of receiver electrodes provided in a detection area and a processing system. The processing system is configured to acquire capacitive touch profiles from the plurality of receiver electrodes and to acquire active pen profiles from the plurality of receiver electrodes that are different from the capacitive touch profiles. The processing system is further configured to adjust the active pen profiles using the capacitive touch profiles to acquire a corrected active pen profile and to use the corrected active pen profile to determine the position of the active pen in the detection area.

[0009] In other aspects, one or more embodiments relate to a processing system configured to obtain a capacitive touch profile from a plurality of receiver electrodes provided in a sensing area of an input device and obtain an active pen profile different from the capacitive touch profile from the plurality of receiver electrodes. The processing system is further configured to adjust the active pen profile using the capacitive touch profile to obtain a corrected active pen profile and identify the position of the active pen in the sensing area using the corrected active pen profile.

Brief Description of the Drawings

[0010] [Figure 1] FIG. 1 illustrates a block diagram of an input device according to one or more embodiments.

[0011] [Figure 2A] FIG. 2A illustrates a capacitive sensing scenario according to one or more embodiments. [Figure 2B] FIG. 2B illustrates a capacitive sensing scenario according to one or more embodiments.

[0012] [Figure 3A] FIG. 3A illustrates a touch coupling model according to one or more embodiments. [Figure 3B] FIG. 3B illustrates a touch coupling model according to one or more embodiments.

[0013] [Figure 4A] FIG. 4A illustrates an exemplary quadrature demodulation according to one or more embodiments. [Figure 4B] FIG. 4B illustrates an exemplary quadrature demodulation according to one or more embodiments.

[0014] [Figure 5] FIG. 5 illustrates the correction of an active pen profile according to one or more embodiments.

[0015] [Figure 6A] FIG. 6A illustrates an example of correcting an active pen profile according to one or more embodiments. [Figure 6B] FIG. 6B illustrates an example of correcting an active pen profile according to one or more embodiments.

[0016] [Figure 6C] FIG. 6C illustrates an example of adjacent values in an active pen profile according to one or more embodiments. [Figure 6D] FIG. 6D illustrates an example of adjacent values in an active pen profile according to one or more embodiments. [Figure 6E] FIG. 6E illustrates an example of adjacent values in an active pen profile according to one or more embodiments.

[0017] [Figure 7] FIG. 7 illustrates a flowchart according to one or more embodiments.

[0018] [Figure 8] FIG. 8 illustrates a flowchart according to one or more embodiments. DETAILED DESCRIPTION OF THE INVENTION

[0019] The following detailed description of the invention is merely exemplary in nature and is not intended to limit the disclosed technology or the application or use of the disclosed technology. Further, there is no intention to be bound by any theory, whether explicit or implicit, presented in the above technical field, background art, or the following detailed description of the invention.

[0020] In the following description of the detailed embodiments, many specific details are presented in order to provide a deeper understanding of the disclosed technology. However, it will be apparent to those skilled in the art that the disclosed technology may be practiced without these specific details. In other instances, well-known configurations are not described in detail to avoid unnecessarily complicating the description.

[0021] Throughout the application, ordinal numbers (e.g., 1st, 2nd, 3rd, etc.) may be used as adjectives for elements (i.e., any noun in the application). The use of ordinal numbers does not suggest or produce a particular ordering of elements, nor does it limit any element to a single element, unless explicitly disclosed by the use of words such as “before,” “after,” “single,” or other similar terms. Rather, the use of ordinal numbers is for distinguishing elements from one another. For example, the 1st element is distinct from the 2nd element, the 1st element may encompass more than one element, and in the ordering of elements, it may follow (or precede) the 2nd element.

[0022] Various embodiments of this disclosure provide input devices and methods for detecting touch (e.g., finger) and active pen. Touch and active pen may be present simultaneously in the detection area, and the presence of a finger or palm may cause touch interference, resulting in degradation of input provided by the active pen, as discussed with reference to Figures 2 and 3. One or more embodiments of this disclosure perform an operation to compensate for touch interference, thereby enabling accurate detection of the active pen in the detection area even in the presence of touch.

[0023] Figure 1 is a block diagram of an example of an 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). In this specification, the term “electronic system” (or “electronic device”) means any system capable of processing information electronically. Some non-limiting examples of electronic systems include personal computers such as desktop computers, laptop computers, and netbooks, tablets, web browsers, e-book readers, smartphones, personal digital assistants (PDAs), game consoles, and in-car infotainment systems.

[0024] In Figure 1, the input device (100) is shown as a proximity sensor device (e.g., a “touchpad” or “touch sensor device”) configured to detect input provided by one or more input objects (140) in a detection area (120). Exemplary input objects include a stylus, an active pen, and a finger (142). Furthermore, the specific input objects present in the detection area may vary across one or more gestures.

[0025] The detection area (120) encompasses any space above, around, and / or near the input device (100) in which the input device (100) can detect user input (e.g., user input provided by one or more input objects). The specific size, shape, and location of the detection area can vary widely depending on the embodiment.

[0026] The input device (100) may use any combination of sensor components and detection techniques to detect user input in the detection area (120). The input device (100) comprises one or more detection elements to detect user input. As a non-limiting example, the input device (100) may use capacitive techniques.

[0027] In some capacitive implementations of the input device (100), a voltage or current is applied to generate an electric field. A nearby input object causes a change in the electric field, resulting in a detectable change in the capacitive coupling, which can be detected as a change in voltage, current, etc.

[0028] Some capacitive implementations may use an array of capacitive sensing elements or other regular or irregular patterns to generate an electric field. In some capacitive implementations, separate sensing elements may be ohmic short-circuited to form a larger sensor electrode. Some capacitive implementations use a resistance sheet that can have uniform resistance.

[0029] Some capacitive implementations employ a “self-capacitance” (or “absolute capacitance”) sensing method based on changes in the capacitive coupling between the sensor electrode and the input object. In various embodiments, an input object near the sensor electrode changes the electric field near the sensor electrode, thereby changing the measured capacitive coupling. In one implementation, the absolute capacitance sensing method operates by modulating the sensor electrode with respect to a reference voltage (e.g., system ground) and detecting the capacitive coupling between the sensor electrode and the input object. The reference voltage may be substantially constant or variable. In various embodiments, the reference voltage may be system ground. The measurement obtained by the absolute capacitance sensing method is sometimes called the absolute capacitance measurement.

[0030] Some capacitive implementations employ a “mutual capacitance” (or “transmitter capacitance”) sensing method based on changes in the capacitive coupling between sensor electrodes. In various embodiments, an input object near the sensor electrodes changes the electric field between the sensor electrodes, and thus changes the capacitive coupling being measured. In one implementation, the mutual capacitance sensing method operates by detecting the capacitive coupling between one or more transmitter sensor electrodes (also referred to as “transmitter electrodes” or “transmitter (Tx)”) and one or more receiver sensor electrodes (also referred to as “receiver electrodes” or “receivers (Rx)”). The transmitter sensor electrodes may be modulated with respect to a reference voltage (e.g., system ground) to transmit a transmitter signal. The receiver electrodes may be kept substantially constant with respect to the reference voltage to facilitate the reception of the resulting signal. The reference voltage may be a substantially constant voltage, and in various embodiments, the reference voltage may be system ground. In some embodiments, both the transmitter sensor electrodes and the receiver sensor electrodes may be modulated. The transmitter electrodes transmit a transmitter signal and are modulated with respect to the receiver electrodes to facilitate the reception of the resulting signal. The resulting signal may include effects corresponding to one or more transmitter signals and / or one or more environmental interference sources (e.g., other electromagnetic signals). These effects may be the transmitter signal, changes in the transmitter signal caused by interference from one or more input objects and / or the environment, or other such effects. The sensor electrodes may be dedicated transmitters or receivers and may be configured to both transmit and receive. The measurement obtained by the mutual capacitance sensing method is sometimes called a mutual capacitance measurement.

[0031] In Figure 1, the processing system (110) is shown as part of the input device (100). The processing system (110) is configured to activate the hardware of the input device (100) to detect an input in the sensing region (120). One or more steps described in the flowcharts of Figures 7 and 8 may be performed by the processing system (110). The processing system (110) may comprise one or more integrated circuits and / or some or all of other circuit components. For example, a processing system for a mutual capacitance sensor device may comprise a transmitter circuit configured to transmit a signal at a transmitter sensor electrode and / or a receiver circuit configured to receive a signal at a receiver sensor electrode. Furthermore, a processing system for an absolute capacitance sensor device may comprise a driver circuit configured to apply an absolute capacitance signal to the sensor electrodes and / or receiver electrodes configured to receive the signal at those sensor electrodes. In one or more embodiments, a processing system for a combination type mutual and absolute capacitance sensor device may comprise any combination of the mutual and absolute capacitance circuit sections described above. In some embodiments, the processing system (110) may also include electronically readable instructions, such as firmware code, software code and / or similar.

[0032] The processing system (110) may be implemented as a set of modules that handle different functions of the processing system (110). For example, the processing system (110) may include a decision circuit unit (150) for determining when at least one input object was in the detection area, identifying the signal-to-noise ratio (SNR), identifying the position information of the input object, identifying a gesture, determining an action to be performed based on the gesture, a combination of gestures or other information, and / or performing other actions. The modules may include software that can be executed on hardware and / or a processor.

[0033] The sensor circuit (160) may have the function of transmitting a transmitter signal and driving a sensing element to receive a result signal. For example, the sensor circuit (160) may include a sensing circuit coupled to a sensing element. The sensor circuit (160) may include, for example, a transmitter module and a receiver module. The transmitter module may include a transmitter circuit coupled to some of the sensing elements that perform transmission. The receiver module may include a receiver circuit coupled to some of the sensing elements that perform reception, and may have the function of receiving a result signal.

[0034] Figure 1 illustrates the decision circuit section (150) and the sensor circuit section (160), but in one or more embodiments, alternative or additional modules may be present. Exemplary alternative or additional modules include a hardware actuation module for operating hardware such as sensor electrodes and a display screen (155), a data processing module for processing data such as sensor signals and location information, a reporting module for reporting information, an identification module configured to identify gestures such as mode change gestures, and a mode change module for changing the operating mode.

[0035] In some embodiments, the processing system (110) directly responds to user input (or lack thereof) in the detection area (120) by performing one or more actions. Exemplary actions include changing the operating mode, along with graphical user interface (GUI) actions and other functions such as cursor movement, selection, and menu navigation. In some embodiments, the processing system (110) provides information about the input (or lack thereof) to a part of the electronic system (for example, to a central processing system of the electronic system, separated from the processing system (110), if such a separate central processing system exists). In some embodiments, a part of the electronic system processes the information received from the processing system (110) and operates based on the user input to facilitate any kind of action, including, for example, mode change actions and GUI actions.

[0036] In some embodiments, the input device (100) includes a touchscreen interface, and the sensing area (120) overlaps at least a portion of the active area of ​​the display screen (155). For example, the input device (100) may include substantially transparent sensor electrodes that overlap the display screen and provide a touchscreen interface for the associated electronic system. The display screen may be any type of dynamic display capable of displaying a visual interface to the user, and may include any type of light-emitting diode (LED), organic light-emitting diode (OLED), micro-LED, liquid crystal display (LCD), or other display technology. The input device (100) and the display screen may share physical elements. For example, in some embodiments, some of the same electrical components may be used for display and sensing. In various embodiments, one or more display electrodes of the display device may be configured for both display updating and input sensing. In another example, the display screen may be operated partially or entirely by a processing system (110).

[0037] Figure 1 illustrates the arrangement of the components, but other arrangements may be used without departing from the scope of the present invention. For example, various components may be combined to form a single component. In other examples, a function performed by a single component may be performed by two or more components.

[0038] Referring to Figure 2A, one or more capacitive detection scenarios are illustrated. In the capacitive detection scenario (200), a palm or finger (290) and an active pen (280) are simultaneously present in the detection area (120). To determine the position of the palm or finger (290) and the position of the active pen (280), a detection operation may be performed using a first electrode (202) aligned to a first (vertical) coordinate axis and a second electrode (204) aligned to a second (horizontal) coordinate axis. In the example in Figure 2A, the first and second electrodes (202, 204) are vertical and horizontal rods, respectively. Other electrode shapes and patterns may be used without departing from the present disclosure.

[0039] Capacitive sensing operations (e.g., absolute capacity sensing and mutual capacity sensing) may be performed to determine the position of the palm or fingers (290).

[0040] In one or more embodiments, a first electrode (202) and / or a second electrode (204) are used in an absolute capacitance sensing method to locate an input object such as a palm or finger (290). The presence or absence of a palm or finger (290) near the first and / or second sensor electrodes (202, 204) changes the electric field near the sensor electrodes, and thus changes the capacitance coupling being measured. The change in capacitance coupling is measured across a column formed by the first electrode (202) and / or across a row formed by the second electrode (204), which may form an absolute capacitance touch profile. A capacitance image that may extend across the entire sensing area (120) may be formed by the change in capacitance coupling measured across the rows and columns. Other forms of capacitive sensing may be used without departing from the present disclosure. For example, transformer capacitance sensing may be used.

[0041] In one or more embodiments, first and second electrodes (202, 204) may be used as receiving electrodes to receive pen signals emitted by an active pen (280). The position of the active pen (280) may be determined based on the amplitude of the pen signals received by the first and second electrodes (202, 204). Thus, an active pen profile may be generated in the same way as a capacitive touch profile, and a combination of active pen profiles may constitute an active pen image. A direct spatial correspondence may exist between the active pen profile and the capacitive touch profile. In other words, for values ​​in the capacitive touch profile at individual positions, there may be corresponding values ​​in the active pen profile at the same position. Further details regarding the acquisition of the position of the active pen (280) will be described later.

[0042] Referring to Figure 2B, a capacitive sensing scenario in one or more embodiments is illustrated. In the capacitive sensing scenario (250), the user places their palm or fingers (290) on the sensing area (120). While the palm or fingers (290) are on the sensing area, the user uses the active pen (280) to draw a geometric figure including lines. In one or more embodiments, when compensation is enabled and the input device (100) is activated, the lines (296) are straight and free of artifacts. However, when compensation is disabled and the input device (100) is activated, the lines (292) include an artifact (294) that causes the lines to be jagged. In this example, the jagged line artifact (294) appears in Figure 2B in an area demarcated by two horizontal lines. These two horizontal lines may represent the vertical range in contact with the palm or fingers (290). Thus, touching the detection area (120) with the palm or finger (290) may interfere with the processing of the pen signal.

[0043] Next, the cause of the jagged line artifact (294) will be discussed with reference to Figures 3A and 3B. Furthermore, compensation for touch interference will be explained with reference to Figures 3A, 3B, 4A, 4B, 5, 6A, 6B, 6C, 6D, 6E, and 7.

[0044] Referring to Figure 3A, one or more touch coupling models according to one or more embodiments are illustrated. The touch coupling model (300) includes an active pen (310) that transmits a pen signal (396) received by a receiver electrode (320). The pen signal (e.g., a square wave) may be emitted at the pen tip (314). To compensate for potential fluctuations that cause the emission of the pen signal (396) at the pen tip (314), the potential of the pen body (314) may fluctuate in the opposite direction to the potential at the pen tip (314). Thus, the pen body (312) may emit an inverted pen signal (398).

[0045] FIG. 3A includes three capacitances to illustrate how a pen signal (396) and an inverted pen signal (398) can be received by a receiver electrode (320). Assume that the receiver electrode (320) is one of the second electrodes (204) of FIG. 2A. More specifically, assume that the receiver electrode (320) is one of the second electrodes that is very close to the pen tip (314) and the palm or finger (290 of FIG. 2A). In this case, capacitance C pen2s provides capacitive coupling between the pen tip (314) and the receiver electrode (320). Thus, the pen signal (396) can be coupled to the receiver electrode (320) through C pen2s . Further, capacitance C pen2hand provides capacitive coupling between the pen body (312) and the user's hand. Capacitance C hand2s provides capacitive coupling between the user's hand and the receiver electrode (320), and capacitance C hand2sysgnd provides capacitive coupling between the user's hand and the system ground (GND). Thus, the inverted pen signal (398) can be coupled to the receiver electrode through C pen2hand and C hand2s . As a result, the inverted pen signal (398) can interfere with the pen signal (396) on the receiver electrode (320). The degree of interference can depend on various factors, as discussed next.

[0046] If there is good coupling between the hand and the system ground, C hand2sysgnd may be more dominant than C hand2s . In this case, the inverted pen signal (398) may not be very strongly coupled to the receiver electrode (320), and thus, the interference caused by the inverted pen signal (398) may be negligible. However, if the coupling between the hand and the system ground is weak, the coupling of the inverted pen signal (398) to the receiver electrode (320) may not be negligible. To obtain further insight into the coupling of the inverted pen signal (398) to the receiver electrode (320), the touch coupling model (300) illustrated in FIG. 3A can be represented by the equivalent touch coupling model of FIG. 3B.

[0047] Referring to Figure 3B, a touch coupling model (350) according to one or more embodiments is illustrated. The touch coupling model (350) can be understood as equivalent to the model (300) illustrated in Figure 3A. C1 is an equivalent capacitor that contributes to the coupling of the inverted pen signal (398) to the receiver electrode (320). C2 does not provide additional coupling of the inverted pen signal (398) to the receiver electrode (320). Consequently, C3 also does not contribute to additional coupling of the inverted pen signal (398) to the receiver electrode (320). If C1 is removed, no coupling of the inverted pen signal (398) to the receiver electrode (320) will occur. Since the circuit in Figure 3A and the circuit in Figure 3B are equivalent, C1 can be calculated as follows:

[0048]

number

[0049] C hand2s This can be measured, for example, using absolute capacity measurement. pen2hand This depends on how or where the pen is held by the user, and some variation may exist, but in the first approximation, it may be considered constant. hand2sysgnd This may be measured and therefore may be considered known. Thus, C1 can be calculated in the above equation. C1 is the C in the numerator multiplied by the gains formed by the other terms in the above equation. hand2s The measured value, i.e., C1 = gain * C hand2s It can be expressed as follows.

[0050] Here,

number

[0051] Rewritten in this format, this suggests that correction of the active pen profile affected by touch interference can be achieved by adjusting the active pen profile using a capacitive touch profile scaled by the gain. As suggested by the touch coupling model (300), the gain is C hand2sysgnd It depends on C. hnd2sysgnd As the gain increases, it approaches zero. In other words, under good ground mass conditions, the gain is zero or close to zero, and therefore, to obtain a properly corrected active pen profile, no correction or only a small correction is needed. However, under low ground mass (LGM) conditions, the gain can be important and therefore can provide correction to adjust the active pen profile in which touch is present. Ground mass refers to the electrical coupling to free space (e.g., air or vacuum). Large objects, such as the human body or a vehicle, have a large surface area that contributes to the coupling, and therefore have good coupling to free space. Unless connected to a power source or placed on a large conductive surface, a telephone, due to its small size, has very little coupling to free space. This is often called low ground mass (LGM). Therefore, a telephone placed on a pillow or cardboard box has very little ground mass. However, if a person is holding the telephone in one hand, the telephone has good ground.

[0052] Those skilled in the art will understand that the touch coupling models (300, 350) are simplified representations of actual capacitive sensing scenarios. Other models may model additional details and therefore may include additional resistance, capacitance, etc., without departing from the disclosure.

[0053] The following discussion describes the correction of the active pen profile affected by the presence of touch, according to one or more embodiments. Several steps may be performed. Roughly speaking, (i) a capacitive touch profile is obtained, (ii) an active pen profile is obtained, and (iii) a corrected active pen profile is obtained by adjusting the active pen profile using the capacitive touch profile. The corrected active pen profile may be used to determine the position of the active pen in the sensing area. The highest value in the active pen profile may indicate the position of the active pen. Spatial interpolation may be used to interpolate adjacent values.

[0054] A capacity touch profile can be obtained, for example, by performing absolute capacity detection as described above.

[0055] Furthermore, an active pen profile can be obtained as described above. In one or more embodiments, the active pen signal may generate a pen signal that is not synchronized with the demodulation circuit of the input device. Therefore, quadrature demodulation may be performed to enable proper measurement of the amplitude of the pen signal received by the receiver electrode of the input device.

[0056] Figures 4A and 4B illustrate orthogonal demodulation according to one or more embodiments.

[0057] Referring to Figure 4A, an exemplary quadrature demodulation (400) for an active pen profile across multiple receiver electrodes is illustrated. At each receiver electrode, four values ​​are obtained using demodulation calculations at different delays (0°, 90°, 180°, 270°) of quadrature demodulation. In this example, assume that the active pen is located near receiver electrode 5, and further, that the finger is located near receiver electrode 13. In one or more embodiments, quadrature demodulation calculates a single value (amplitude) for each receiver electrode. This single value is obtained by first identifying the maximum delta across all receiver electrodes. In this example, the maximum delta is found for the values ​​obtained at 90° and 180° delays at electrode 5. Next, the delta is calculated for the delays in which the maximum delta was identified. Thus, in Figure 4A, the record for the 90° delay is subtracted from the record for the 180° delay.

[0058] Referring to Figure 4B, the exemplary quadrature demodulation (450) is the result of the above calculation to obtain a single value for each of the receiver electrodes. The resulting active pen profile also has a peak at the active pen position (electrode 5) and a depression at the finger position (electrode 13), which may represent the inverted pen signal coupled to the electrode by the finger.

[0059] While specific types of orthogonal demodulation have been described, other types of orthogonal demodulation may be performed as long as they do not deviate from this disclosure.

[0060] Referring to Figure 5, the correction of the active pen profile (500) in one or more embodiments is illustrated. The left half of Figure 5 illustrates a schematic depiction of a detection area having electrodes oriented vertically on the vertical coordinate axis in a configuration for active pen profile detection. The right half of Figure 5 illustrates a schematic depiction of a detection area having electrodes oriented vertically on the vertical coordinate axis in a configuration for capacitive touch profile detection. In Figure 5, the input object 540 of the detection area is in contact with the receiver electrodes 505, 511, 512 and 513. In one example, the input object 540 may be the palm of a user that generates a "negative disturbance from the palm" in the pen profile (left half of Figure 5) extending at least from the receiver electrode 511 to at least the receiver electrode 505. The input object 540 may also generate a "positive disturbance from the palm" in the touch profile, extending at least from the receiver electrode 511 to at least the receiver electrode 505.

[0061] As described above with reference to Figures 3A and 3B, the correction may be performed by adjusting the values ​​of the active pen profile by adding the corresponding values ​​of the gain-scaled capacitive touch profile.

[0062] The gain is, as derived above,

number

[0063] The gain may be specified as follows. Let's assume the calculation is performed on electrode n. The value of the active pen profile for electrode n is D. nThis is the case (left half of Figure 5). Therefore, the value of the active pen profile for receiver electrode 511 is D0, the value of the active pen profile for receiver electrode 512 is D1, and the value of the active pen profile for receiver electrode 513 is D2. D0, D1, and D2 represent the profile regions corresponding to the "pen tip" position near the upper edge of the pen profile region in the left half of Figure 5.

[0064] The value of the capacitive touch profile for electrode n is E n This is the case (right half of Figure 5). Therefore, the capacitance touch profile value for receiver electrode 511 is E0, the capacitance touch profile value for receiver electrode 512 is E1, and the capacitance touch profile value for receiver electrode 513 is E2.

[0065] The value of the corrected active pen profile D for electrode n. n ' is an operation: D n '=D n +E n *Gain The gain may be obtained by the following: The gain is determined in the left half of Figure 5 based on the profile values ​​outside the hatched profile region D (represented by D0, D1, and D2). For example, the receiver electrode 505 is outside the profile region D, and the value of the active pen profile is A tmax (See the left half of Figure 5). The receiver electrode 505 also has a capacitive touch profile value of B tmax (See the right half of Figure 5). Under these conditions, Gain = -A tmax / B tmax That is the case.

[0066] The gain may be calculated dynamically. If the area of ​​the required input object (e.g., palm or fingers) is not available to update the gain, the last known gain may be used. This can occur, for example, when the pen position in an active pen profile or capacitive touch profile coincides with the palm or finger position. Referring to Figure 5, this is A tmax / B tmax This would occur if the pen were in a position where it could be obtained.

[0067] Figures 6A and 6B provide examples of active pen profile correction according to one or more embodiments.

[0068] Referring to Figure 6A, an example of correcting the active pen profile (600) is provided for a scenario where the active pen position does not overlap with the finger position. The table on the left shows the time evolution of the active pen profile. The table in the middle shows the time evolution of the capacitive touch profile. The table on the right shows the time evolution of the corrected active pen profile. Time is taken vertically; that is, in the tables, the top row of data values ​​is for the earliest point in time. Each column is for one electrode. The data illustrated in the left, middle, and right tables are for the same electrode. All three tables are color-coded. Diagonal hatching patterns indicate values ​​higher than the baseline (e.g., 21 to 243), cross hatching patterns indicate values ​​near the baseline (e.g., -17 to 20), and vertical hatching patterns indicate values ​​lower than the baseline (e.g., -93 to -18).

[0069] In the active pen profile (table on the left), the pen is stationary. The highest value in the active pen profile is at electrode 3, and an increased value is also found at electrode 2, indicating that the pen is stationary near electrode 3, slightly shifted toward electrode 2. Over time (moving downwards in the table), the finger is placed in the detection area. In the detection area, pen disturbance is observed at the finger position. At the finger position, the coupling of the inverted pen signal to the electrode in the vicinity of the finger causes the active pen profile value to decrease (below the baseline). However, because there is no spatial overlap, this pen disturbance does not have a detrimental effect on the value at the active pen position.

[0070] In a capacitive touch profile, the position of the finger is visible when it is near an electrode.

[0071] In the corrected active pen profile, pen disturbances are effectively eliminated, and the pen position remains clearly visible. The correction of the active pen profile to obtain the corrected active pen profile is performed as described above. In the example in Figure 6A, a fixed gain of 0.7 was used to perform the correction.

[0072] Referring to Figure 6B, an example of correcting the active pen profile (620) is provided for a scenario where the active pen's position overlaps with the finger's position. The table in Figure 6B is a continuation of the table in Figure 6A at a later point in time.

[0073] In the active pen profile (left table), the pen gradually moves from left to right. Initially, the highest value in the active pen profile is at electrode 9, but later (bottom of the table) the highest value is at electrode 10. However, despite the gradual movement, the active pen profile does not show a smooth change. Instead, it appears as if an abrupt switch occurred from electrode 9 to electrode 10, as shown by the dashed line. The cause of this abrupt transition is pen disturbance, which causes interference at the actual position of the pen in Figure 6B. Figures 2A and 2B illustrate situations that cause such jagged line artifacts. Pen disturbance reduces the magnitude of the active pen profile values ​​at the pen's position.

[0074] An example is illustrated in Figure 6C, which shows three adjacent values ​​in the active pen profile (630). Because the magnitude of the values ​​decreases in the active pen profile, only one of these values ​​is above the baseline (dashed line). Therefore, smooth spatial interpolation between adjacent values ​​is not possible. Consequently, if the pen position gradually shifts from one electrode to an adjacent electrode, the active pen position between those electrodes will show an abrupt, step-like change. The situation is slightly better in the exemplary adjacent values ​​in the active pen profile (640) in Figure 6D, although two of the three values ​​are barely above the baseline. Figure 6E illustrates a desirable scenario for exemplary adjacent values ​​in the active pen profile (650). As a result, all three values ​​are significantly above the baseline, allowing for smooth spatial interpolation between adjacent values ​​even when the active pen position shifts.

[0075] Continuing the discussion in Figure 6B, in the capacitive touch profile (center table), the finger position remains in the same location as initially illustrated in the capacitive touch profile in Figure 6A. Referring to the corrected active pen profile in Figure 6B, the decrease in the active pen profile value is compensated for by the compensation, resulting in a smooth spatial interpolation between electrode 9 and electrode 10.

[0076] Figure 7 illustrates a flowchart according to one or more embodiments. While various steps in the flowchart are presented and described in order, those skilled in the art will understand that some or all of the steps may be performed in a different order, combined or omitted, and that some or all of the steps may be performed in parallel. Additional steps may also be performed. Therefore, the scope of the disclosure should not be considered to be limited to the specific arrangement of steps illustrated in Figure 7.

[0077] The flowchart in Figure 7 illustrates a method (700) for compensating for touch interference for an active pen. One or more of the steps in Figure 7 may be performed by components of the input device (100). The steps described below describe a single capacitive touch profile and a single active pen profile, but these steps may be performed for multiple touch profiles to obtain an image frame. Furthermore, the operation may be repeated over time. The described operation may be used in the presence of multiple active pens.

[0078] In step 702, the capacity touch profile is obtained. The capacity touch profile can be obtained as described above.

[0079] In step 704, the active pen profile is obtained. The active pen profile can be obtained as described above.

[0080] In step 706, a corrected active pen profile is obtained by adjusting the active pen profile using a capacitive touch profile. The corrected active pen profile can be obtained as described above.

[0081] In step 708, the position of the active pen in the detection area is determined using a corrected active pen profile. The position of the active pen can be obtained as described above.

[0082] Figure 8 illustrates a flowchart according to one or more embodiments. While various steps in the flowchart are presented and described sequentially, those skilled in the art will understand that some or all of the steps may be performed in a different order, combined, or omitted, and that some or all of the steps may be performed in parallel. Additional steps may also be performed. Therefore, the scope of the disclosure should not be considered to be limited to the specific arrangement of steps illustrated in Figure 8.

[0083] The flowchart in Figure 8 illustrates a method (800) for compensating for touch interference for an active pen using multiple coordinate axes. The gain may be filtered and adjusted when an optimal tuning region (e.g., receiver electrode 505 in Figure 5) is identified and confirmed. For example, tuning may not be performed when the pen is positioned on the end electrode. In addition, tuning may be applied to the electrodes of the vertical and horizontal coordinate axes, and may be used separately for each coordinate axis. If tuning is not performed for one coordinate axis for several seconds, the other coordinate axis may provide assistance and update the gain for both coordinate axes.

[0084] One or more of the steps in Figure 8 may be performed by components of the input device. The steps described below describe a single capacitive touch profile and a single active pen profile, but these steps may be performed for multiple touch profiles to obtain an image frame. Furthermore, the operation may be repeated over time. The described operation may be used in the presence of multiple active pens.

[0085] In step 802, the input device acquires a first capacitive touch profile along the first coordinate axis from multiple receiver electrodes in the sensing area.

[0086] In step 804, the input device determines that, in the first capacitive touch profile, each capacity measurement affected by the input object is also affected by the active pen. Since each capacity measurement affected by the input object is also affected by the active pen, the capacity measurement at the input object's position may not be used to adjust the active pen profile in the first coordinate axis.

[0087] In step 806, the input device acquires a second capacitance touch profile along the second coordinate axis from multiple receiver electrodes in the sensing area. The second capacitance touch profile may be acquired in accordance with the decision in step 804, or it may be acquired independently of the decision in step 804.

[0088] In step 808, the input device selects a second capacitive touch profile and adjusts the active pen profile accordingly. In one or more embodiments, the input device determines that at least one capacitive measurement of the position of the input object in the second capacitive touch profile is not affected by the active pen.

[0089] In step 810, the input device acquires an active pen profile. The active pen profile can be acquired as described above.

[0090] In step 812, the input device acquires a corrected active pen profile by adjusting the active pen profile using the second capacitive touch profile.

[0091] In step 814, the input device uses a corrected active pen profile to determine the position of the active pen in the detection area.

[0092] In some embodiments, an estimated transformer capacitance profile may be used instead of an absolute detection profile for the E0, E1, and E2 regions on the right side of Figure 5. Similarly, an estimated transformer capacitance profile may be used instead of an absolute detection profile for the Btmax electrode on the right side of Figure 5.

[0093] It should be noted that if one coordinate axis (vertical or horizontal) is blocked and the active pen profile cannot be updated for a period of time, scaling may be used so that the other coordinate axis can provide a tuning value for that axis. The scaling may be a known or pre-measured ratio, for example 70%, and may be based on a phone model. For example, suppose the X axis has a tuning value of 700 and the Y axis is blocked and a tuning value is needed. Multiplying the X tuning value by 70% gives 490, which may then be used for the Y axis.

[0094] Embodiments of the present disclosure thus provide methods and systems for correcting touch interference of an active pen. Additional components, not shown, may be included. For example, in one embodiment, a state machine is configured to determine whether or not to perform the method for correcting touch interference. The state machine may check whether the active pen and touch are simultaneously present in the sensing area. The state machine may perform the method only if simultaneous presence is detected. The state machine may not perform the method otherwise, to avoid a situation where artifacts may be introduced by unnecessary corrective actions. Implementations of the methods and apparatus as described may further include various filtering operations. For example, a temporary filter may be applied to the position of the active pen to address problems that may arise from the rapid movement of a finger or palm in the sensing area. In this scenario, the filter may address a mismatch between the touch detection rate (e.g., 60 Hz) and the active pen detection rate (e.g., 240 Hz) to avoid motion artifacts in the pen trajectory.

[0095] Although the present invention has been described in terms of a limited number of embodiments, those skilled in the art who are interested in this disclosure will understand that it is possible to derive other embodiments that do not deviate from the scope of the present invention disclosed herein.

Claims

1. A method for capacitive sensing, comprising: obtaining a capacitive touch profile from a plurality of receiver electrodes provided in a sensing area of an input device; obtaining an active pen profile different from the capacitive touch profile from the plurality of receiver electrodes; obtaining a corrected active pen profile by adjusting the active pen profile using the capacitive touch profile; identifying the position of an active pen in the sensing area using the corrected active pen profile. A method as described above. A method.

2. The method according to claim 1, wherein obtaining the active pen profile includes receiving radiation from the active pen by the plurality of receiver electrodes. The method according to claim 1.

3. The method according to claim 1, wherein the corrected active pen profile is obtained by scaling the capacitive touch profile by a gain and then adding the capacitive touch profile to the active pen profile. The method according to claim 1.

4. The method according to claim 1, further comprising: before obtaining the corrected active pen profile, determining whether a touch exists in the sensing area in addition to the active pen; and obtaining the corrected active pen profile based on the determination that the touch exists. The method according to claim 1.

5. An input device, comprising: a plurality of receiver electrodes provided in a sensing area; a processing system configured to obtain a capacitive touch profile from the plurality of receiver electrodes, obtain an active pen profile different from the capacitive touch profile from the plurality of receiver electrodes, obtain a corrected active pen profile by adjusting the active pen profile using the capacitive touch profile, and identify the position of an active pen in the sensing area using the corrected active pen profile.

6. The input device according to claim 5, wherein the corrected active pen profile is obtained by scaling the capacitive touch profile by a gain and then adding the capacitive touch profile to the active pen profile. The input device according to claim 5.

7. The processing device further configured to determine whether a touch exists in the sensing area in addition to the active pen before obtaining the corrected active pen profile. ​ ​ ​ ​ ​ ​ ​ ​ configured to obtain the corrected active pen profile based on the determination that the touch exists The input device according to claim 5. **Claim 8** obtaining a capacitance touch profile from a plurality of receiver electrodes provided in a detection area of an input device obtaining an active pen profile different from the capacitance touch profile from the plurality of receiver electrodes obtaining a corrected active pen profile by adjusting the active pen profile using the capacitance touch profile configured to identify the position of an active pen in the detection area using the corrected active pen profile processing system **Claim 9** The corrected active pen profile is obtained by scaling the capacitance touch profile by a gain and then adding the capacitance touch profile to the active pen profile The processing system according to claim 8. **Claim 10** The processing system further determines whether a touch exists in the detection area in addition to the active pen before the corrected active pen profile is obtained, and is configured to obtain the corrected active pen profile based on the determination that the touch exists The processing system according to claim 8.

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