Apparatus and method for uplink channel compensation for touch screen devices

Abstract

An apparatus and method for detecting and / or discriminating body contact and modifying at least one uplink channel parameter to compensate for the effect of a user's hand or other body part contacting a touchscreen on the strength of a capacitive coupled uplink signal provided by a host device to a handheld input device.

Description

Background Technology

[0001] Electronic devices, especially tablets or smartphones, can accept input via handheld peripheral input devices such as pens or styluses, and can then act as host devices for the input devices. The input device can be manually held by the user relative to the touchscreen to provide input to the electronic device. The position of the input device on the touchscreen is related to the virtual information depicted on the touchscreen. The touch position of the input device can be detected due to small changes in capacitance at the contact points on the touchscreen. Summary of the Invention

[0002] This disclosure is provided to present a selection of concepts in a simplified form, which are further described in the following detailed description. This disclosure is not intended to identify key or essential features of the claimed subject matter, nor is it intended to limit the scope of the claimed subject matter. The claimed subject matter is also not limited to implementations that address any or all of the shortcomings indicated herein.

[0003] According to one aspect, the disclosure in some embodiments relates to an apparatus for controlling an inking process via an input device on a touchscreen, the apparatus comprising:

[0004] A body contact detector for detecting body contact of a user's body parts on the touchscreen during concurrent touches on the input device; and

[0005] A modulator for temporarily altering at least one transmission parameter of the uplink channel from the touchscreen driver of the touchscreen to the receiver of the input device in response to detected physical contact.

[0006] According to another aspect, a host device or digitizer includes the means described in the first aspect.

[0007] According to another aspect, the disclosure in some embodiments relates to an apparatus for controlling the inking process via an input device on a touchscreen, the apparatus comprising:

[0008] A communication unit is used to receive body contact feedback signals from the host device of the touchscreen; and

[0009] A sensitivity controller, in response to the reception of the body contact feedback signal, controls the sensitivity of the receiver used to receive uplink signals from the touchscreen driver of the touchscreen.

[0010] According to another aspect, an input device or an apparatus according to the aforementioned aspect.

[0011] According to another aspect, a method for controlling the inking process via an input device on a touchscreen includes:

[0012] Detecting the user's body parts touching the touchscreen during concurrent touch on the input device; and

[0013] In response to detected physical contact, at least one transmission parameter of the uplink channel from the touchscreen driver of the touchscreen to the receiver of the input device is temporarily changed.

[0014] According to another aspect, a method for controlling the inking process via an input device on a touchscreen includes:

[0015] Receive body contact feedback signals from the host device of the touchscreen; and

[0016] In response to the reception of the body contact feedback signal, the sensitivity of the receiver used to receive uplink signals from the touchscreen driver of the touchscreen is controlled.

[0017] Unless otherwise defined, all technical and / or scientific terms used herein have the same meaning as commonly known to those skilled in the art. While similar or equivalent methods and materials to those described and materials herein may be used to practice or test embodiments of this disclosure, exemplary methods and / or materials are described below. Furthermore, the materials, methods, and examples are illustrative only and are not intended to impose any necessary limitations. Attached Figure Description

[0018] To aid in understanding this disclosure and to illustrate how these embodiments can be implemented, reference is made to the accompanying drawings by way of example only, in which:

[0019] Figure 1 This is a schematic block diagram of an example system including a stylus and a host device.

[0020] Figure 2 This is a schematic block diagram indicating the capacitance that affects the uplink signal strength during physical contact on a touchscreen.

[0021] Figure 3 This is a schematic flowchart illustrating the uplink channel compensation process during physical contact.

[0022] Figure 4 This is a schematic block diagram of an example system with uplink channel compensation at the host device, and

[0023] Figure 5 This is a schematic block diagram of an example host device with uplink channel compensation at the active stylus. Detailed Implementation

[0024] This disclosure relates to adaptive uplink channel compensation for touch-sensitive display systems.

[0025] Figure 1This is a schematic diagram of an example system including a host device 20 (e.g., an electronic device with a touch-sensitive display, including smartphones, tablets, watches, desktop computers, gaming devices, wearable devices, televisions, video conferencing systems, etc.) and a handheld stylus peripheral device (“stylus”) 10 having an input / output unit 12 for receiving uplink signals received from the host device 20. Furthermore, the stylus 10 may include a pressure sensor (not shown) configured to sense pressure or force applied to the tip electrode 14 of the stylus 10. The stylus may be able to transmit the pressure sensor’s output data (e.g., measured pressure or force data) to the host device 20 via a downlink signal. The host device 20 includes a touchscreen (TS) 22 (touch-sensitive display) and an operating system (OS) 30 for controlling the touchscreen 22.

[0026] The stylus 10 is used to transmit user input to the host device 20. The touchscreen 22 may include a built-in digitizer to sense signals transmitted from the stylus 10. The user interacts with the digitizer by positioning and moving the tip electrode 14 of the stylus 10 on the sensing surface of the touchscreen 22. The position of the tip electrode 14 of the stylus 10 relative to the sensing surface is tracked by the digitizer and interpreted as user commands. In some technologies, the position of the stylus 10 may be determined based on the detection of capacitive coupling between the tip electrode 14 of the stylus and one or more electrodes of the digitizer. For example, the touchscreen 22 may include a digitizer with multiple X and Y oriented conductors or resistive films to receive downlink signals transmitted from the tip electrode 14 of the stylus 10. In some technologies, to accurately identify the tip position, a transmitting electrode is physically positioned within the writing tip electrode 14 of the stylus 10.

[0027] The stylus 10 can be classified as a passive or active stylus. A passive stylus utilizes a sensing method based on changes in the capacitive coupling between sensor electrodes deposited on a touchscreen sensor and an input object (such as a rubber-tipped stylus). In contrast, an active stylus drives a unique modulated downlink signal between the tip electrode 14 of the stylus 10 and the electrode grid or array of the digitizer's touchscreen sensor, utilizing a sensing method based on changes in the capacitive coupling between the sensor electrodes. The digitizer detects at least one position of the stylus 10 based on the emitted downlink signal, and the detected position provides input to a host device 20 associated with the digitizer. The detected position can then be interpreted as a user command. Typically, the digitizer can be integrated with the display screen 22, for example, to form a touch-sensitive display device.

[0028] In addition, the stylus 10 can transmit detected pressure information to the host device 20 for digital inking weighting. One of the characteristics of digital inking is force / pressure sensitivity, which allows the user of the stylus 10 to control the line thickness.

[0029] If the stylus 10 is an active stylus, it can generate a modulated downlink signal that can be detected by a digitizer. This signal can be encoded using information such as device identification, operating mode (e.g., writing, erasing), pressure / force information, tilt information, and other information. This information can be assigned to various locations on the signal.

[0030] If the stylus 10 is a passive stylus, it can utilize a sensing method based on changes in the capacitive coupling between sensor electrodes deposited on the touchscreen sensor and the input object (such as a rubber-tipped stylus). In such an implementation, the stylus 10 can use communication protocols such as Wi-Fi or Bluetooth to transmit detected pressure / force information to the host device 20.

[0031] Information transmitted by the stylus 10 (e.g., pressure / force information) is detected by the host device 20 and used to provide functionality in the display of the host device 20. For example, the host device 20 can detect that the stylus 10 is in writing mode via identifiable pressure / force information. The host device 20 can use this information (in combination with position information detected by a digitizer) to display digital inking with thickness or color depending on the pressure / force information encoded in the signal. For example, a light touch can indicate that a relatively thin or light line should be drawn on the display of the touchscreen 22. As the user increases the pressure / force on the stylus 10, the weight of the line (e.g., darkness or thickness) can be increased accordingly.

[0032] Therefore, the downlink transmission of information is achieved through electrostatic communication from the stylus 10 to the digitizer of the host device 20, wherein the digitizer is configured to extract the position of the stylus based on the downlink signal, and the stylus 10 can modulate the data on the downlink signal to transmit the stylus identity, the force applied to its tip electrode 14, the pressure level, button indication, etc.

[0033] Additionally, the uplink transmission of information is achieved via a communication link from the digitizer of host device 20 to the stylus 10. The stylus 10 can use the uplink transmission link to obtain, for example, digitizer timing and cycle length in order to be able to inscribe on the display of host device 20, and / or to receive data from the digitizer, such as which frequency will be used to transmit downlink signals.

[0034] As an example, a touchscreen driving signal can be applied to the touchscreen 22. The touchscreen driving signal may include an uplink signal for synchronization with the stylus 10 and a touch sensor driving signal for sensing touch input applied to the touchscreen 22. When the stylus 10 contacts the touchscreen 22, the stylus 10 receives the uplink signal from the touchscreen 22, generates a downlink signal (i.e., a pen driving signal) based on this uplink signal and in sync with the touch sensor driving signal, and outputs the generated downlink signal to the touchscreen 22, for example, through the tip electrode 14. Because the downlink signal is synchronized with the touch sensor driving signal, it is used to improve the sensitivity of the touch sensor driving signal.

[0035] However, when the user's palm or other body part touches the touchscreen 22 along with the stylus 10, the stylus 10 may fail to properly receive uplink signals. Here, the palm can be the hand holding the stylus 10 or the hand without the stylus 10. In this case, the stylus 10 may fail to synchronize with the touchscreen 22, thus preventing normal operation.

[0036] Figure 2 This is a schematic block diagram indicating the capacitance that affects the uplink signal strength during physical contact on a touchscreen.

[0037] As initially mentioned, physical contact, for example, by the user's hand 50 on the touchscreen 22 of the host device can reduce the impact of the stylus 10's tip electrode 14 and tip capacitor C. t The strength of the uplink signal received at the input / output unit 12 of the tip receiver. The uplink signal is generated at the touchscreen driver 25 of the touchscreen 22. In particular, when the host device (e.g., a personal computer) is in battery mode or connected to the power grid via a two-hole plug without a connector to ground potential EP1, the grounding of the touchscreen 22 and its embedded digitizer is only through the system-to-ground capacitance C. s2g Coupled to ground. The stylus user's hand 50 is connected to the palm capacitor C. p Coupled to touchscreen 22 and via hand-to-ground capacitance C h2g Coupled to ground. Additionally, the stylus is grounded (i.e., the housing) via the "hand-to-housing capacitance" C when the stylus 10 is held. h2e Coupled to the user's hand 50.

[0038] In an embedded configuration, the digitizer's touch sensing element is directly integrated into one or more layers of the display stack of the touchscreen 22 itself. Therefore, the touch sensor substrate can be removed by combining the display unit and touch sensing element of the touchscreen display into a single structure, making the touchscreen device thinner and lighter. Previous designs with a separate sensor layer are referred to as out-cell configurations.

[0039] Therefore, when a user touches the touchscreen 22 with his / her hand 50, a portion of the uplink signal is coupled to the pen ground via the user's body, which reduces the uplink signal entering the tip electrode 14 of the stylus 10.

[0040] The following section explains in more detail the uplink signal at the tip electrode 14 of the stylus 10 and... Figure 2 The example shown illustrates the calculation of the dependence of parasitic capacitance.

[0041] The hand potential V at 50 on the user's hand h Reference touchscreen 22 ground potential V ul It can be represented as follows:

[0042] V h =~V ul *C p / (C s2g +C p (1)

[0043] Using equation (1) above, the current I of the uplink signal at the tip electrode 14 is... t It can be represented as follows:

[0044] I t =~(V) ul -V h C t s (2)

[0045] I t =~V ul (1-C p / (C s2g +C p ))C t s (3)

[0046] Where s represents the complex frequency.

[0047] For C p =10pF and C s2g In the typical case of 5pF, the uplink signal attenuation factor is 0.33 (or -10dB).

[0048] To mitigate the problem of uplink signal reduction due to body contact, an uplink channel compensation method is proposed in the embodiment. By means of the method, at least one parameter (e.g., channel amplification, spatial distribution, channel sensitivity, etc.) of the uplink channel from the touch screen driver 25 to the stylus 10 is temporarily modified to compensate for the signal reduction at the touch screen 22 during body contact.

[0049] Figure 3This is a schematic flowchart of the uplink channel compensation process during physical contact.

[0050] The initial sensing operation S310 detects parameters of the touch action at the touch screen 22. This can be achieved by analyzing raw touch data based on the touch sensor drive signal and the downlink signal of the stylus 10 to obtain touch parameters (e.g., capacitance, position, phase, amplitude, single-point touch, multi-point touch, etc.).

[0051] More specifically, the touchscreen 22 can be implemented as a capacitive touchscreen that senses touch input via multiple capacitive sensors, where capacitance can be classified as self-capacitance and mutual capacitance. Self-capacitance can be formed along a single layer of conductor lines formed in one direction. Mutual capacitance can be formed between two conductor lines perpendicular to each other. The touch sensor can be implemented by a mutual capacitance sensor, which may include a transmit (Tx) electrode line, a receive (Rx) electrode line intersecting the Tx electrode line, and a touch sensor formed at the intersection of the Tx electrode line and the Rx electrode line. The Tx electrode line is a drive signal line that provides charge to the touch sensor by applying a touch sensor drive signal (and / or a downlink signal from the stylus 10) to the touch sensor. The Rx electrode line is a sensor line connected to the touch sensor and providing the touch sensor's charge to the touch driving device. In the mutual capacitance sensing method, charge is provided to the touch sensor by applying a touch sensor drive signal (and / or downlink signal) to the Tx electrode via the Tx electrode line, and the capacitance change of the touch sensor is sensed by the Rx electrode and Rx electrode line synchronized with the touch sensor drive signal (and / or stylus downlink signal), thereby identifying touch input from a conductive object.

[0052] Then, touch analysis operation S320 is performed to analyze at least one touch parameter. In one example, the touch sensing system of the digitizer of touchscreen 22 can simultaneously sense two touch inputs, such as body contact input from a user's body part (e.g., a finger or palm) and stylus touch input from stylus 10. Body contact input can be sensed based on the analysis results of raw touch data according to the touch sensor drive signal, while stylus touch input can be sensed based on the analysis results of raw touch data according to the downlink signal of stylus 10.

[0053] In the subsequent identification or detection operation S330, the analysis results of the touch parameters are used to detect body contact by distinguishing between stylus touch and body contact during concurrent stylus touch. For example, the downlink signal of stylus 10 and the touch sensor drive signal of the digitizer may have the same phase, but the magnitude of the downlink signal (e.g., pulse amplitude) may be set to be greater than the magnitude of the touch sensor drive signal, thereby distinguishing the touch line data of the location touched by stylus 10 from the touch line data of the location touched by the user's body to easily distinguish stylus touch input and body contact input (thus detecting concurrent body contact).

[0054] Then, in the subsequent decision operation S340, it is determined whether physical contact has occurred (i.e., been detected) and whether compensation is needed to adjust the uplink signal. If no adjustment is needed, the process jumps back to the sensing operation S310 and starts again. Conversely, if adjustment is needed (e.g., if physical contact is detected), the process proceeds to the compensation operation S350, where at least one parameter of the uplink channel (e.g., amplification, spatial distribution, sensitivity, etc.) is modified to compensate for uplink signal loss or reduction due to detected physical contact.

[0055] Figure 3 The operation can be repeated continuously or intermittently.

[0056] In the following text, different examples of uplink channel compensation will be described.

[0057] Figure 4 This is a schematic block diagram of an example host device with uplink channel compensation.

[0058] Here, adaptive uplink channel compensation can be achieved by modifying the spatial distribution of the active touch sensor elements (antennas) of the digitizer of the touchscreen 22. This can be achieved by locally disabling each touch sensor element at a defined location and / or area of ​​detected body contact, thereby reducing the body capacitance C to the uplink signal. p .

[0059] Typically, uplink signals are transmitted from all sensor elements of the touch sensor on the touchscreen 22 to increase the capacitance of the tip electrode 14 of the stylus 10 (e.g., when the stylus 10 is hovering over the touchscreen 22).

[0060] according to Figure 4The host device 20 includes a touchscreen 22 and a touchscreen driver (TSD) 25 that controls the touchscreen 22's touch sensors (e.g., an array or matrix of sensor elements or antennas). The touchscreen driver 25 applies touchscreen drive signals to the sensor elements of the touch sensors and senses the amount of charge change in the sensor elements to determine touch input. The touchscreen drive signals include uplink signals and touch sensor drive signals.

[0061] In addition, the touch screen driver 25 analyzes the charge change of the touch sensor based on whether there is touch input, determines or detects touch input, and calculates the coordinates of the touch input position.

[0062] Touchscreen 22 can be configured as an embedded liquid crystal display (LCD) panel, which also includes touchscreen functionality by positioning at least one of the touch layers (typically an emitter (TX) layer) beneath a color filter glass. Furthermore, the TX layer is typically shared with a common electrode (reference layer) of touchscreen 22. Touchscreen driver 25 can be a capacitive touchscreen driver used to measure capacitance on an array of electrode (sensor elements), such as an array comprising multiple emitter (TX) electrodes and multiple receiver (RX) electrodes. Integrated circuits are typically integrated circuits (ICs) located on the LCD substrate glass, driving timing and video signals to the LCD. While the above description is for embedded LCDs, similar stack-ups exist for other display types such as active-matrix organic light-emitting diodes (AMOLEDs).

[0063] Based on the sensor signals generated by the touchscreen driver 25, the touch detector 24 detects the touch parameters of the touch action, as described above. Figure 3 The sensing operation S310 is described.

[0064] Additionally, the downlink signal received by the touch detector 24 from the touchscreen driver 25 is forwarded to an inking control (INK-CTRL) application or unit (e.g., a drawing application or unit) 21, where it is used to generate digital inking at a defined location of the stylus 10 with weight (e.g., thickness or darkness) or other inking parameters corresponding to the reported force, pressure, or inking level included in the downlink signal.

[0065] The touch parameters determined by touch detector 24 are provided to body contact detector (BTD) 28 of the digitizer, which is configured to identify the location of body parts (e.g., hands or fingers) on the touchscreen, as described above. Figure 2The touch analysis and identification or detection operations S320 and S330 are described. Based on the identified location of the detected body contact, the body contact detector 28 controls the touchscreen driver 25 to disable selected sensor elements of the touch sensor at or around the location of the detected body contact, thereby reducing the impact of touch contact via capacitance C. p The amount of uplink signal lost in part of the uplink channel path.

[0066] As an example, the body contact detector 28 of the digitizer can be controlled by the touchscreen driver 25 to disable selected sensor elements by connecting them to ground potential or another reference potential, thereby reducing the stimulated uplink signal of the user's body parts.

[0067] In another embodiment, adaptive uplink channel compensation can be achieved by modifying the amplification of the uplink signal at the touchscreen driver 25 of the touchscreen 22. This can be achieved by controlling the amplification factor of the amplifier in the touch driver circuit 25. More specifically, based on detected body contact, the body contact detector 28 controls the touchscreen driver 25 of the digitizer to increase the level of the uplink signal to compensate for any signal degradation caused by body contact and to ensure good inking performance. Typically, the digitizer can transmit the uplink signal with low or medium power or voltage. When body contact is indicated by the body contact detector 28, the touchscreen driver 25 can be controlled by the body contact detector 28 to momentarily or temporarily increase the voltage or power of the uplink signal to improve the inking performance at the inking control unit or application 21.

[0068] Note that spatial modifications to the selected sensor elements of the touch sensor (e.g., selective disabling) can be combined with modifications to the amplification factor of the touchscreen driver 25 to achieve more effective compensation for uplink signal degradation during body contact.

[0069] Touch detector 24, touch screen driver 25, body contact detector 28, ink control unit or application 21, and other system components of host device 20 may be implemented in application-specific integrated circuit (ASIC), system-on-chip (SOC), field-programmable gate array (FPGA), microprocessor unit, etc.

[0070] Figure 5 This is a schematic block diagram of an example host device 20 with uplink channel compensation at the active stylus 10. In this example, uplink channel compensation is achieved by modifying the sensitivity of the receiver unit (Rx) 13 of the stylus 10.

[0071] The tip electrode 14 of the stylus 10 can be formed of a conductive material such as metal and protrudes outward from one side of the housing to serve as an input / output electrode. Since the tip electrode 14 serves as an input / output electrode, the structure of the stylus 10 is advantageously simplified. When the tip electrode 14 touches the touchscreen 22 of the host device 20, the tip electrode 14 is coupled to the touchscreen 22 at the contact point. The tip electrode 14 receives the touchscreen drive signal (uplink signal) from the touchscreen 22 at the contact point and outputs the pen drive signal (downlink signal) generated within the stylus 10 to the contact point of the touchscreen 22. When the tip electrode 14 touches the touchscreen 22 of the host device 20, the input / output unit 12 of the stylus 10 is electrically connected to the tip electrode 14 and the receiving unit 13 during the receiving period and to the transmitting unit (Tx) 15 during the transmitting period, thereby temporally separating the receiving timing of the uplink signal (touchscreen drive signal) and the transmitting timing of the downlink signal (pen drive signal).

[0072] The receiving unit 13 includes at least one amplifier and at least one comparator, and performs digital processing on the uplink signal input through the input / output unit 12 during the receiving period.

[0073] The stylus 10 may also include one or more processing units (e.g., a controller (CTRL)) 18, such as having onboard memory for storing user files, user manuals, etc. The memory may be a tangible processor-readable memory and may store processor-readable instructions for communication and digital inking via the host device 20. The stylus 10 may include a display (not shown) that can show the user any of the following: battery power status, current wireless signal strength, or other information associated with the host device 20 configured to receive user input from the stylus 10.

[0074] Processing unit 18 can analyze the pattern of the uplink signal (i.e., pulse duty cycle, number of pulses, etc.) to check its validity. When a normal uplink signal is detected, processing unit 18 determines that the uplink signal is valid and generates a pen drive signal (downlink signal) synchronized with the touch sensor drive signal included in the uplink signal. Processing unit 18 can refer to the signal generation conditions of the installed default parameter set (e.g., period, duty cycle, number, etc.) to generate a downlink signal synchronized with the touch sensor drive signal. Then, processing unit 18 outputs the downlink signal to the tip electrode 14 through input / output unit 12 during the transmission period of the touch period.

[0075] The stylus 10 may further include a wireless communication unit (WCU) 17. The wireless communication unit 170 may be configured to communicate with the host device 20 via Bluetooth, Wi-Fi, Near Field Communication (NFC), etc. The wireless communication unit 17 may include a receiver for receiving communication commands, pairing requests, etc., from the wireless communication unit (WCU) 27 at the host device 20. The stylus 10 may further include a power source (not shown), which may include a battery for powering various components of the stylus 10. The battery may be rechargeable, replaceable, disposable, etc.

[0076] In some examples, as a supplement or alternative, the stylus 10 can be connected to the host device 20 via, for example, a Universal Serial Bus (USB) connection and can communicate with the host device via this connection.

[0077] Furthermore, the processing unit 18 can be configured to control the sensitivity of the receiving unit 13 based on a feedback signal (FS) received from the host device 20 via the wireless communication unit 17. Sensitivity control can be implemented by temporarily applying a bias voltage to at least one amplifier of the receiving unit 13 to control the receiver gain. Such gain control may be necessary to adjust the sensitivity of the receiving unit 13 to better receive the uplink signal in cases where the uplink signal level is reduced due to physical contact.

[0078] Therefore, in this example, adaptive uplink channel compensation can be achieved by modifying the sensitivity of the receiving unit 13 at the stylus 10. More specifically, in response to detected body contact, the body contact detector 28 forwards a feedback signal indicating a body contact event to the transmitter of the wireless communication unit 27 of the host device 20, which in turn transmits the feedback signal to the receiver of the wireless communication unit 17 of the stylus 10. The wireless communication unit 17 of the stylus 10 forwards the received feedback signal to the processing unit 18, which generates a sensitivity control output to control the sensitivity of the receiving unit 13, such that the uplink signal level is momentarily or temporarily increased to compensate for any signal degradation of the uplink signal caused by body contact.

[0079] As another example, the feedback signal can indicate different levels of sensitivity control output to provide an adaptive sensitivity control signal at receiver 12 based on the area and / or intensity of body contact and the resulting estimated reduction in the uplink signal level.

[0080] The stylus 10 may further include a force or pressure sensor (not shown) with optional force or pressure response circuitry (not shown), which, together with the processing unit 18, can be collectively referred to as the inking system. The inking system detects the force or pressure applied to the tip electrode 14, optionally enhances the force or pressure sensitivity, converts the detected force or pressure into an output value (e.g., a reported (inking) level), and transmits the output signal to the host device 20.

[0081] As an example, the output value may be an encoded digitizer signal (i.e., a downlink signal) and transmitted to the digitizer of host device 20. At host device 20, the received output value is detected and forwarded to ink control application or unit (e.g., drawing application or unit) 21, where the output value is used to generate digital ink at a determined location on stylus 10 with weight (e.g., thickness or darkness) or other ink parameters corresponding to the adapted and reported force, pressure, or ink level.

[0082] The input / output unit 12, receiving unit 13, transmitting unit 15, processing unit 18, and other system components of the stylus 10 can be implemented in application-specific integrated circuits (ASICs), system-on-a-chip (SOCs), field-programmable gate arrays (FPGAs), microprocessor units, etc.

[0083] The stylus 10 may include one or more buttons (not shown) for changing the stylus's operating mode. For example, when a button is pressed, a signal transmitted to the host device may inform the host device that the stylus 10 is in erase mode. Furthermore, such operating modes may indicate the color of the digital ink, the writing pattern (e.g., dashed lines), and the writing instrument (e.g., brush, pen, marker, pencil). Detected force or pressure may be indicated in different operating modes. For example, when in erase mode, detected force or pressure may indicate the erase thickness. The buttons may also be used to initiate device pairing with the host device 20.

[0084] In each example, the stylus body may be formed of a material suitable for encapsulating the components described herein. The stylus body may be formed of, for example but not limited to, plastic, rubber, metal, carbon fiber, and / or any combination thereof.

[0085] Note that at least one of the aforementioned spatial modifications to the sensor element of the touch sensor and the aforementioned modifications to the amplification factor of the driver at the host device 20 can be combined with the aforementioned sensitivity control of the receiving unit 13 at the stylus 10 to obtain more effective compensation for uplink signal degradation during body contact.

[0086] In summary, the impact of a user's hand or other body parts contacting the touchscreen (when holding the input device (e.g., a stylus or eraser)) on the capacitively coupled uplink signal strength provided by the host device to the input device can be mitigated by detecting and / or identifying body contact and modifying at least one uplink channel parameter to compensate for the impact on the uplink signal. Channel compensation can be achieved by detecting the location of body contact and using the detected location to selectively disable the sensing element of the touch sensor (modifying the spatial distribution of the uplink channel), thereby preventing the provision of uplink signals to the touchscreen sensing element located in the detected body contact area. Alternatively or additionally, channel compensation can be achieved by at least one of the following: increasing the amplification of the touchscreen driver to increase the level of the transmitted uplink signal (modifying the amplification of the uplink channel) or increasing the sensitivity of the receiver at the input device to increase the level of the received uplink signal.

[0087] It will be understood that the above embodiments are described by way of example only. The present invention can be applied to any type of touchscreen system having any type of input device that may involve physical contact with a user. The touchscreen 22 can be implemented based on a liquid crystal display (LCD), a field emission display (FED), a plasma display panel (PDP), an organic light-emitting diode display (OLED), an electrophoretic display, etc.

[0088] More generally, according to the first aspect disclosed herein, an apparatus is provided for controlling the inking process via an input device on a touchscreen, the apparatus comprising:

[0089] A body contact detector is used to detect body contact of a user's body parts on the touchscreen during concurrent touches of the input device; and

[0090] A modulator for temporarily altering at least one transmission parameter of the uplink channel from the touchscreen driver of the touchscreen to the receiver of the input device in response to detected physical contact.

[0091] In various embodiments, the modulator may be configured to modify the uplink channel by temporarily increasing the amplification factor of the touchscreen driver in response to the detected physical contact.

[0092] In various embodiments, the modulator may be configured to: determine the location of a body contact on the touchscreen, and in response to the detected body contact, modify the spatial distribution of the uplink channel by disabling selected sensor elements of the touchscreen's touch sensor at the determined location of the body contact.

[0093] In various embodiments, the modulator may be adapted to disable selected sensor elements by connecting them to a reference potential.

[0094] In various embodiments, the modulator may be configured to modify the uplink channel by temporarily increasing the sensitivity of the receiver at the input device in response to detected physical contact.

[0095] In various embodiments, the modulator may be adapted to increase the sensitivity of the receiver at the input device by signaling a body contact feedback signal from the host device of the touchscreen to the input device.

[0096] In various embodiments, the modulator may be configured to increase the sensitivity of the receiver by initiating gain control of the receiver's amplifier.

[0097] In various embodiments, the apparatus of the first aspect may include a wireless communication unit for signaling the body contact feedback signal to the input device.

[0098] According to the second aspect disclosed herein, a host device or digitizer is provided, including the device of the first aspect, a touch screen, and a touch screen driver.

[0099] According to a third aspect disclosed herein, an apparatus is provided for controlling the inking process via an input device on a touchscreen, the apparatus comprising:

[0100] A communication unit is configured to receive body contact feedback signals from the host device of the touchscreen; and

[0101] A sensitivity controller, in response to the reception of the body contact feedback signal, controls the sensitivity of the receiver used to receive uplink signals from the touchscreen driver of the touchscreen.

[0102] According to a fourth aspect disclosed herein, an input device is provided, the input device including the means of the third aspect and a receiver for receiving uplink signals from a touchscreen driver of a touchscreen.

[0103] In various embodiments, the input device may include a stylus or an eraser.

[0104] According to another aspect disclosed herein, a method for controlling the inking process via an input device on a touchscreen is provided, the method comprising:

[0105] Detecting the user's body parts touching the touchscreen during concurrent touch on the input device; and

[0106] In response to detected physical contact, at least one transmission parameter of the uplink channel from the touchscreen driver of the touchscreen to the receiver of the input device is temporarily changed.

[0107] According to another aspect disclosed herein, a method for controlling the inking process via an input device on a touchscreen is provided, the method comprising:

[0108] Receive body contact feedback signals from the host device of the touchscreen; and

[0109] In response to the reception of the body contact feedback signal, the sensitivity of the receiver used to receive uplink signals from the touchscreen driver of the touchscreen is controlled.

[0110] According to another aspect of the disclosure herein, a computer program implemented on a computer-readable storage is provided, the computer program including code configured to perform the methods of any of the embodiments disclosed herein when run on one or more processors.

[0111] The examples and embodiments described herein can be implemented as logical steps in one or more computer systems. Logical operations can be implemented as: (1) a sequence of processor-implemented steps executed in one or more computer systems; and (2) interconnected machines or circuit modules within one or more computer systems. The implementation is a matter of choice depending on the performance requirements of the computer system used for implementation. Therefore, the logical operations constituting the various examples or embodiments described herein may be referred to differently as operations, steps, objects, or modules. Furthermore, it should be understood that logical operations can be performed in any order, added as needed, or omitted unless expressly stated or required by the language of the claims.

[0112] Once this disclosure is given, other variations and applications of the disclosed technology will become apparent to those skilled in the art. The scope of this disclosure is not limited to the embodiments described above, but is defined only by the appended claims.

Claims

1. An apparatus for controlling the inking process via an input device on a touchscreen, the apparatus comprising: A body contact detector, the body contact detector being used to detect body contact of a user's body parts on the touchscreen during concurrent touch of the input device; as well as A modulator, the modulator being configured to temporarily alter at least one transmission parameter of the uplink channel from the touchscreen driver of the touchscreen to the receiver of the input device in response to detected physical contact. The modulator is configured to modify the uplink channel by temporarily increasing the amplification factor of the touchscreen driver in response to the detected body contact, or by signaling a body contact feedback signal to the input device in response to the detected body contact to temporarily increase the sensitivity of the receiver.

2. The apparatus of claim 1, wherein the apparatus includes a wireless communication unit for signaling the body contact feedback signal to the input device.

3. An apparatus for controlling the inking process via an input device on a touchscreen, the apparatus comprising: A communication unit, the communication unit being used to communicate with the host device of the touch screen; as well as A sensitivity controller is provided to control the sensitivity of the receiver to receive uplink signals from the touchscreen driver of the touchscreen. The communication unit is configured to receive body contact feedback signals from the host device of the touchscreen; as well as The sensitivity controller is configured to control the sensitivity of the receiver in response to the reception of the body contact feedback signal.

4. The apparatus of claim 3, wherein the sensitivity controller is configured to increase the sensitivity of the receiver by initiating gain control of the amplifier of the receiver.

5. An input device comprising the means of claim 3 and a receiver for receiving uplink signals from a touchscreen driver of a touchscreen.

6. The input device of claim 5, wherein the input device includes a stylus or an eraser.

7. A host device, the host device comprising the apparatus, touch screen, and touch screen driver according to claim 1.

8. A method for controlling an inking process on a touchscreen via an input device, the method being performed at a host device and comprising: During concurrent touches on the input device, the user's body parts are detected in physical contact with the touchscreen. as well as In response to detected physical contact, temporarily alter at least one transmission parameter of the uplink channel from the touchscreen driver of the touchscreen to the receiver of the input device, and The modification of the uplink channel is performed by temporarily increasing the amplification factor of the touchscreen driver in response to the detected body contact, or by signaling a body contact feedback signal to the input device in response to the detected body contact to temporarily increase the sensitivity of the receiver.

9. A method for controlling an inking process via an input device on a touchscreen, the method comprising: Receive body contact feedback signals from the host device of the touchscreen; as well as In response to the reception of the body contact feedback signal, the sensitivity of the receiver used to receive uplink signals from the touchscreen driver of the touchscreen is controlled.

10. A computer-readable storage medium storing a computer program comprising code configured to cause the apparatus of claim 1 or 3 to perform the method of claim 8 or 9, respectively.

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