EP4724880A1

EP4724880A1 - Method and apparatus for a stylus to support multiple touch display devices

Info

Publication number: EP4724880A1
Application number: EP23749236.8A
Authority: EP
Inventors: Hu-Chi Chang; Chengliang QIAN; Premal Parekh
Original assignee: Google LLC
Current assignee: Google LLC
Priority date: 2023-07-11
Filing date: 2023-07-11
Publication date: 2026-04-15
Also published as: WO2025014475A1

Abstract

A first stylus sets up a first Bluetooth connection with a first device. The first stylus assigns an uplink code to the first device via the first Bluetooth connection. When receiving the uplink code from touch driving circuitry of the first device, the first stylus sends position information of the first stylus to the touch driving circuitry of the first device. A second stylus sets up a second Bluetooth connection with a second device. The second stylus assigns, via the second Bluetooth connection, a time slot to the second device, and sends a downlink signal at the time slot. When receiving, via the second Bluetooth connection, an acknowledge signal indicating that the downlink signal is received by touch driving circuitry of the second device at the time slot, the second stylus sends position information of the second stylus to the touch driving circuitry of the second device.

Description

METHOD AND APPARATUS FOR A STYLUS TO SUPPORT MULTIPLE TOUCH DISPLAY DEVICES

TECHNICAL FIELD

[0001] The present disclosure relates to a touch sensing system, and more specifically, to a seamless cooperation between a stylus and multiple touch display devices in the touch sensing system.

BACKGROUND

[0002] A touch display device can allow a user to input information or commands by using a finger, a stylus (or a pen), and the like. When the stylus is close to a display panel (or a touchscreen) of the touch display device, the touch display device can detect the stylus and setup a communication (e.g., a bidirectional communication) with the stylus.

SUMMARY

[0003] Aspects of the disclosure provide a method for a stylus to cooperate with one or more touch display devices. The method includes assigning, by the stylus, a first uplink code to a first touch display device of the one or more touch display devices. In response to receiving, by the stylus and from touch driving circuitry of the first touch display device, a first uplink signal including the first uplink code, the method includes sending, from the stylus to the touch driving circuitry of the first touch display device, a first acknowledge (ACK) signal to inform the first touch display device to be ready for receiving a downlink signal from the stylus. The method further includes sending, from the stylus to the touch driving circuitry of the first touch display device, the downlink signal including at least position information or tilt information of the stylus.

[0004] In an embodiment, the method includes establishing, by the stylus, a first Bluetooth connection with the first touch display device, wherein the first uplink code is assigned by the stylus via the first Bluetooth connection to the first touch display device. In example, when a Bluetooth function of the first touch display device is turned on and the stylus is within a Bluetooth connection range (e.g., around 10m) of the first touch display device, the method includes sending a Bluetooth connection request from the stylus to the first touch display device, receiving a Bluetooth ACK signal by the stylus from the first touch display device, and pairing by the stylus with the first touch display device to establish the first Bluetooth connection.

[0005] In an embodiment, the method includes establishing, by the stylus, a second Bluetooth connection with a second touch display device of the one or more touch display devices, assigning, by the stylus and via the second Bluetooth connection, a second uplink code to the second touch display device, and scanning for, by the stylus, the second uplink code. The second uplink code is different from the first uplink code.

[0006] In an embodiment, the first uplink signal includes a beacon for clock synchronization between the stylus and the touch driving circuitry of the first touch display device, and the method includes performing, by the stylus, the clock synchronization based on the beacon included in the first uplink signal.

[0007] In an embodiment, the method includes, after sending the downlink signal, determining whether a second uplink signal including the first uplink code is received by the stylus from the touch driving circuitry of the first touch display device. In response to determining that the second uplink signal including the first uplink code is not received by the stylus, the method further includes running a timer to count a timeout period and stop sending the downlink signal based on the timeout period being greater than a timeout threshold.

[0008] In an embodiment, in response to not receiving the first uplink signal including the first uplink code, the method includes determining whether there is a third touch display device of the one or more touch display devices that was previously and is not currently Bluetooth connected to the stylus, and sending a Bluetooth connection request to the third touch display device based on a determination that there is the third touch display device that was previously and is not currently Bluetooth connected to the stylus.

[0009] In an embodiment, in response to receiving, by the stylus and from the third touch display device, a second ACK signal indicating that the Bluetooth connection request is received by the third touch display device and a third Bluetooth connection is established between the stylus and the third touch display device, the method further includes updating, by the stylus, a list of connected devices to include the third touch display device, and assigning, by the stylus and via the third Bluetooth connection, a third uplink code to the third touch display device, the third uplink code being different from the first uplink code. [0010] Aspects of the disclosure provide an apparatus. Processing circuitry of the apparatus assigns a first uplink code to a first touch display device of one or more touch display devices. In response to receiving, from touch driving circuitry of the first touch display device, a first uplink signal including the first uplink code, the processing circuitry sends, to the touch driving circuitry of the first touch display device, a first ACK signal to inform the first touch display device to be ready for receiving a downlink signal from the apparatus, and sends, to the touch driving circuitry of the first touch display device, the downlink signal including at least position information or tilt information of the apparatus.

[0011] In an embodiment, the processing circuitry establishes a first Bluetooth connection with the first touch display device, wherein the first uplink code is assigned via the first Bluetooth connection to the first touch display device. In example, when a Bluetooth function of the first touch display device is turned on and the apparatus is within a Bluetooth connection range (e.g., around 10m) of the first touch display device, the processing circuitry sends a Bluetooth connection request to the first touch display device, receives a Bluetooth ACK signal from the first touch display device, and pairs with the first touch display device to establish the first Bluetooth connection.

[0012] In an embodiment, the processing circuitry establishes a second Bluetooth connection with a second touch display device of the one or more touch display devices, assigns, via the second Bluetooth connection, a second uplink code to the second touch display device, and scans for the second uplink code. The second uplink code is different from the first uplink code.

[0013] In an embodiment, the first uplink signal includes a beacon for clock synchronization between the apparatus and the touch driving circuitry of the first touch display device. The processing circuitry performs the clock synchronization based on the beacon included in the first uplink signal.

[0014] In an embodiment, after sending the downlink signal, the processing circuitry determines whether a second uplink signal including the first uplink code is received by the apparatus from the touch driving circuitry of the first touch display device. In response to determining that the second uplink signal including the first uplink code is not received by the apparatus, the processing circuitry runs a timer to count a timeout period and stops sending the downlink signal based on the timeout period being greater than a timeout threshold. [0015] In an embodiment, in response to not receiving the first uplink signal including the first uplink code, the processing circuitry determines whether there is a third touch display device of the one or more touch display devices that was previously and is not currently Bluetooth connected to the apparatus, and sends a Bluetooth connection request to the third touch display device based on a determination that there is the third touch display device that was previously and is not currently Bluetooth connected to the apparatus.

[0016] In an embodiment, in response to receiving, from the third touch display device, a second ACK signal indicating that the Bluetooth connection request is received by the third touch display device and a third Bluetooth connection is established between the apparatus and the third touch display device, the processing circuitry updates a list of connected devices to include the third touch display device, and assigns, via the third Bluetooth connection, a third uplink code to the third touch display device, the third uplink code being different from the first uplink code.

[0017] Aspects of the disclosure provide a method for a stylus to cooperate with one or more touch display devices. The method includes assigning, by the stylus, a first time slot to a first touch display device of the one or more touch display devices, and sending, by the stylus, a first downlink signal at the first time slot. Tn response to receiving, by the stylus and from the first touch display device, a first ACK signal indicating that the first downlink signal is received by touch driving circuitry of the first touch display device at the first time slot, the method includes sending, from the stylus to the touch driving circuitry of the first touch display device, a second downlink signal including at least position information or tilt information of the stylus.

[0018] In an embodiment, the method includes establishing, by the stylus, a first Bluetooth connection with the first touch display device, wherein the first time slot is assigned by the stylus via the first Bluetooth connection to the first touch display device, and the first ACK signal is received by the stylus via the first Bluetooth connection. In example, when a Bluetooth function of the first touch display device is turned on and the stylus is within a Bluetooth connection range (e.g., around 10m) of the first touch display device, the method includes sending a Bluetooth connection request from the stylus to the first touch display device, receiving a Bluetooth ACK signal by the stylus from the first touch display device, and pairing by the stylus with the first touch display device to establish the first Bluetooth connection. [0019] In an embodiment, the first Bluetooth connection includes a beacon for clock synchronization between the stylus and the touch driving circuitry of the first touch display device. The processing circuitry performs the clock synchronization based on the beacon included in the first Bluetooth connection.

[0020] In an embodiment, the method includes establishing, by the stylus, a second Bluetooth connection with a second touch display device of the one or more touch display devices, assigning, by the stylus and via the second Bluetooth connection, a second time slot to the second touch display device, the second time slot being different from the first time slot, and sending, by the stylus, a third downlink signal at the second time slot.

[0021] In an embodiment, the method includes receiving, by the stylus and via the first Bluetooth connection, an indication to stop sending the second downlink signal.

[0022] In an embodiment, in response to not receiving the first ACK signal, the method includes determining whether there is a third touch display device of the one or more touch display devices that was previously and is not currently Bluetooth connected to the stylus and sending a Bluetooth connection request to the third touch display device based on a determination that there is the third touch display device that was previously and is not currently Bluetooth connected to the stylus.

[0023] In an embodiment, in response to receiving, by the stylus and from the third touch display device, a second ACK signal indicating that the Bluetooth connection request is received by the third touch display device and a third Bluetooth connection is established between the stylus and the third touch display device, the method includes updating, by the stylus, a list of connected devices to include the third touch display device, assigning, by the stylus and via the third Bluetooth connection, a third time slot to the third touch display device, the third time slot being different from the first time slot or the second time slot, and sending, by the stylus, a fourth downlink signal at the third time slot.

[0024] Aspects of the disclosure provide an apparatus. Processing circuitry of the apparatus assigns a first time slot to a first touch display device of one or more touch display devices, and sends a first downlink signal at the first time slot. In response to receiving, from the first touch display device, a first ACK signal indicating that the first downlink signal is received by touch driving circuitry of the first touch display device at the first time slot, the processing circuitry sends, to the touch driving circuitry of the first touch display device, a second downlink signal including at least position information or tilt information of the apparatus.

[0025] In an embodiment, the processing circuitry establishes a first Bluetooth connection with the first touch display device, wherein the first time slot is assigned by the apparatus via the first Bluetooth connection to the first touch display device, and the first ACK signal is received by the apparatus via the first Bluetooth connection. In example, when a Bluetooth function of the first touch display device is turned on and the apparatus is within a Bluetooth connection range (e.g., around 10m) of the first touch display device, the processing circuitry sends a Bluetooth connection request to the first touch display device, receives a Bluetooth ACK signal from the first touch display device, and pairs with the first touch display device to establish the first Bluetooth connection.

[0026] In an embodiment, the first Bluetooth connection includes a beacon for clock synchronization between the apparatus and the touch driving circuitry of the first touch display device. The processing circuitry performs the clock synchronization based on the beacon included in the first Bluetooth connection.

[0027] In an embodiment, the processing circuitry established a second Bluetooth connection with a second touch display device of the one or more touch display devices, assigns, via the second Bluetooth connection, a second time slot to the second touch display device, the second time slot being different from the first time slot and sends a third downlink signal at the second time slot.

[0028] In an embodiment, the processing circuitry receives, via the first Bluetooth connection, an indication to stop sending the second downlink signal.

[0029] In an embodiment, in response to not receiving the first ACK signal, the processing circuitry determines whether there is a third touch display device of the one or more touch display devices that was previously and is not currently Bluetooth connected to the apparatus and sends a Bluetooth connection request to the third touch display device based on a determination that there is the third touch display device that was previously and is not currently Bluetooth connected to the apparatus.

[0030] In an embodiment, in response to receiving, from the third touch display device, a second ACK signal indicating that the Bluetooth connection request is received by the third touch display device and a third Bluetooth connection is established between the apparatus and the third touch display device, the processing circuitry updates a list of connected devices to include the third touch display device, assigns, via the third Bluetooth connection, a third time slot to the third touch display device, the third time slot being different from the first time slot or the second time slot, and sends a fourth downlink signal at the third time slot.

[0031] Aspects of the disclosure provide a non-transitory computer-readable medium storing instructions which when executed by an apparatus cause the apparatus to perform any one or a combination of the above methods.

BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Various embodiments of this disclosure that are proposed as examples will be described in detail with reference to the following figures, wherein like numerals reference like elements, and wherein:

[0033] FIG. 1 shows an exemplary touch sensing system according to embodiments of the disclosure;

[0034] FIG. 2 shows an exemplary procedure according to embodiments of the disclosure;

[0035] FIG. 3 shows an exemplary timing diagram according to embodiments of the disclosure;

[0036] FIG. 4 shows an exemplary procedure according to embodiments of the disclosure;

[0037] FIG. 5 shows an exemplary timing diagram according to embodiments of the disclosure;

[0038] FIG. 6 shows an exemplary timing diagram according to embodiments of the disclosure;

[0039] FIG. 7 shows an exemplary timing diagram according to embodiments of the disclosure; and

[0040] FIG. 8 shows a computer system according to embodiments of the disclosure.

DETAILED DESCRIPTION OF EMBODIMENTS

[0041] The detailed description set forth below in connection with the appended drawings is intended as a description of various configurations and is not intended to represent the only configurations in which the concepts described herein may be practiced. The detailed description includes specific details for the purpose of providing an understanding of various concepts. However, these concepts may be practiced without these specific details.

[0042] Several aspects of a touch sensing system will now be presented with reference to various apparatuses and methods. These apparatuses and methods will be described in the following detailed description and illustrated in the accompanying drawings by various blocks, components, circuits, processes, algorithms, etc. (collectively referred to as “elements”). These elements may be implemented using electronic hardware, computer software, or any combination thereof. Whether such elements are implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system.

[0043] FIG. 1 shows an exemplary touch sensing system 100 according to embodiments of the disclosure. The touch sensing system 100 can include a plurality of touch display devices (e.g., touch display devices 110-112) and a stylus 120. It is noted that a number of the plurality of touch display devices in the touch sensing system 100 is not limited in this disclosure, and three touch display devices 110-112 are shown in FIG. 1 for exemplary illustration. In the following description, the touch display device 110 is illustrated in details as an example, and other touch display device(s) in this disclosure can be described in a similar way.

[0044] The touch display device 1 10 can provide an image (or video) display function to display an image (or video) and a touch sensing function to receive input information or command information from a finger, a passive pen, an active pen such as the stylus 120, or the like. The touch display device 110 can be, for example, a television (TV), a monitor, or a mobile device such as a tablet or a smart phone.

[0045] According to aspects of the disclosure, the touch display device 110 can include a touchscreen 130, a display driver integrated circuit (DDIC) (or display driving circuitry) 140, a touch integrated circuit (TIC) (or touch driving circuitry) 150, a host system (or processing circuitry) 160, and a Bluetooth module (or wireless communication circuitry) 170.

[0046] The touchscreen 130 can include a cover panel 131, a touch panel 132, and a display panel 133.

[0047] The cover panel 131 can include a transparent material and be used for protecting the touch panel 132 and the display panel 133. In an example, the cover panel 131 can include a glass or a plastic material. [0048] The touch panel 132 can include a plurality of touch sensors that senses a touch input from a user. In an example, the plurality of touch sensors can be capacitive touch sensors. In an example, the touch input can be a direct contact of a conductive object (e.g., the user's finger, the user's palm, a touch pen, a passive pen, an active pen, and the like) on the touchscreen 130. In an example, the touch input can be an indirect contact of the conductive object that is in proximity of the touchscreen 130.

[0049] The display panel 133 can be any type of display panels such as a light-emitting diode (LED) display panel, an organic LCD (OLED) display panel, an active-matrix OLED (AMOLED) display panel, a liquid crystal display (LCD) panel, a field emission display (FED) panel, a plasma display panel (PDP), an electrophoretic display (EPD) panel, or the like.

[0050] It is noted that a location of the touch panel 132 relative to the display panel 133 is not limited in this disclosure. In an example such as FIG. 1, the touch panel 132 can be on top of the display panel 133. In another example, the touch panel 132 can be underneath the display panel 133.

[0051] The DDIC 140 can drive the display panel 133 to perform the image display function of the touch display device 100. The DDIC 140 can receive a command signal from the host system 160 based on image data to be displayed and send a display driving signal DD to the display panel 133 during a display driving period.

[0052] The TIC 150 can drive and sense the touch panel 132 to perform the touch sensing function of the touch display device 130. The TIC 150 can send a touch driving signal TD during a touch driving period to the touch panel 132 and receive from the touch panel 132 a touch sensing signal TS that senses charge variations of the plurality of touch sensors of the touch panel 132. By analyzing the charge variations of the plurality of touch sensors, the TIC 150 can determine presence or absence of a touch input and obtain touch input information (e.g., position information and/or tilt information) of the touch input if present. The touch input information of the touch input can be sent back to the host system 160 for further processing.

[0053] The touch driving signal TD and the display driving signal DD need to be synchronized with each other in order to avoid a flicker issue of the display panel 133. The display driving signal DD can include a vertical synchronization signal Vsync, a horizontal synchronization signal Hsync, and the like. In an example, the touch driving signal TD needs to be synchronized with the vertical synchronization signal Vsync. [0054] The Bluetooth module 170 can be used for pairing the touch display device 110 to the stylus 120 via a Bluetooth connection when the Bluetooth function of the touch display device 110 is turned on and the stylus 120 is within a Bluetooth connection range (e.g., around 10m) of the touch display device 110. After the Bluetooth pairing succeeds, the stylus 120 can store an identity of the touch display device 110, such as a media access control (MAC) address of the touch display device 110.

[0055] In an embodiment, stylus configuration information of the stylus 120 can be sent from the touch display device 110 to the stylus 120 via the Bluetooth connection. The stylus configuration information can include various settings (e.g., erase setting or ink setting) of the stylus 120.

[0056] In an embodiment, stylus status information of the stylus 120 can be sent from the stylus 120 to the touch display device 110 via the Bluetooth connection. The stylus status information can include battery information and pressure information of the stylus 120 for example.

[0057] According to aspects of the disclosure, the stylus 120 can include a Bluetooth circuit block (BT) 121, a data processing module (MCU) 122, a communication module (Tx/Rx) 123, and an electrode (ET) 124.

[0058] The Bluetooth circuit block (or Bluetooth circuitry) 121 can be used for pairing the stylus 120 to the touch display device 110 or any other device having a Bluetooth function. In an embodiment, the stylus 120 can use a Bluetooth low energy (BLE) technology to pair with a device such as the touch display device 110.

[0059] The data processing module (or processing circuitry) 122 can receive data from the Bluetooth circuit block 121 and/or the communication module 123, process the data, and send commands to the Bluetooth circuit block 121 and/or the communication module 123 based on the processed data. In an example, the data processing module 122 can be a microcontroller (MCU).

[0060] The communication module (or communication circuitry) 123 can set up (or establish) a bidirectional communication with a TIC of touch display device (e.g., the TIC 150 of the touch display device 110), when a distance between the stylus 120 and a touchscreen of the touch display device (e.g., the touchscreen 130 of the touch display device 110) is within a communication range (e.g., within 3cm) of the bidirectional communication. The bidirectional communication can enable the stylus 120 and the touch display device 110 to enter into a stylus operation mode and a stylus scan mode, respectively, so that the stylus 120 can send a touch input to the touch display device 110 and the touch display device 110 can receive the touch input from the stylus 120.

[0061] In the bidirectional communication, a signal provided from the TIC 150 of the touch display device 110 to receiving circuitry (Rx) of the communication module 123 of the stylus 120 can be referred to as an uplink signal, and a signal provided from transmitting circuitry (Tx) of the communication module 123 of the stylus 120 to the TIC 150 of the touch display device 110 can be referred to as a downlink signal. The uplink signal can include a beacon for clock synchronization between the TIC 150 of the touch display device 110 and the communication module 123 of the stylus 120. The downlink signal can include at least position information and/or tilt information of a stylus tip of the stylus 120.

[0062] In an embodiment, the bidirectional communication can be performed through a capacitive coupling between the touch sensors of the touch panel 132 and the electrode 124 of the stylus 120. The uplink and downlink signals can be transmitted via the touch sensors of the touch panel 132 and the electrode 124 of the stylus 120. In an example, the electrode 124 can be located at the stylus tip of the stylus 120

[0063] When the stylus 120 is moved out of the communication range of the bidirectional communication between the communication module 123 of the stylus 120 and the TIC 150 of the touch display device 110, the touch display device 110 is not able to receive a touch input from the stylus 120. For example, when the stylus 120 is lift up or moved away from the touchscreen 130 of the touch display device 110, the touch display device 110 is not able to receive the position information and/or tilt information of the stylus tip of the stylus 120.

[0064] It is noted that the touch display device 110 and/or the stylus 120 can include other modules such as power module, Wi-Fi module, and various sensor modules (e g., pressure sensor, inertial sensor, etc.). The wireless connection between the touch display device 110 and the stylus 120 is not limited to the Bluetooth connection in this disclosure, and can be Wi-Fi connection, near-field connection, or the like.

[0065] Typically, when a user wants to use a stylus, which is already paired with a first touch display device, to cooperate with a second touch display device, the user has to first manually unpair the stylus from the first touch display device and then pair the stylus to the second touch display device. This manual operation limits the user to seamlessly use the stylus among multiple touch display devices.

[0066] Accordingly, this disclosure provides methodologies for a user to seamlessly use a stylus among multiple touch display devices.

[0067] According to embodiments of the disclosure, a stylus (e.g., stylus 120) can pair with each of multiple touch display devices in a touch sensing system (e.g., touch sensing system 100) via a respective Bluetooth connection when the Bluetooth functions of the multiple touch display devices are turned on and the multiple touch display devices are within the Bluetooth connection range of the stylus. After the respective Bluetooth connection succeeds, the stylus can assign a different uplink code to each paired touch display device via the respective Bluetooth connection. After receiving the respective assigned uplink code, each paired touch display device can start sending the respective assigned uplink code via a TIC of the respective paired touch display device. Then, the stylus can enter into a scan mode to scan for the assigned uplink codes.

[0068] In an embodiment, a first paired touch display device (e.g., touch display device A 110) of the multiple paired touch display devices in the touch sensing system can be paired to the stylus via a first Bluetooth connection. In response to the success of the first Bluetooth connection, the stylus can send, to the first paired touch display device and via the first Bluetooth connection, a first uplink code (e.g., 001). In response to receiving the first uplink code, the first paired touch display device can start sending the first uplink code.

[0069] In an example, if the stylus is moved close to the first paired touch display device, a first distance between the stylus and the first paired touch display device can be within a first communication range (e.g., within 3cm) of a first bidirectional communication between a communication module (e.g., communication module 123) of the stylus and a first TIC (e.g., TIC 150) of the first paired touch display device. The stylus can receive, from the first paired touch display device and via the first bidirectional communication, the first uplink code that is assigned by the stylus to the first paired touch display device. The first uplink code can be sent in a first uplink signal from the first TIC of the first paired touch display device to the communication module of the stylus. In addition to the first uplink code, the first uplink signal can include a first beacon that is used by the stylus to perform a first clock synchronization to synchronize a clock of the stylus to a first TIC clock of the first TIC of the first paired touch display device. [0070] It is noted that the clock of the stylus can be a clock of the communication module of the stylus or a clock of a data processing module (e.g., data processing module 122) of the stylus. The clock of the stylus can also be referred to as a stylus clock in this disclosure.

[0071] After performing the first clock synchronization, the stylus can obtain a first downlink frequency for sending first downlink signals. Further, the stylus can send back a first acknowledge (ACK) signal to the first paired touch display device, and enter into the stylus operation mode. The first ACK signal can be sent in one of the first downlink signals with the first downlink frequency from the communication module of the stylus to the first TIC of the first paired touch display device. In the stylus operation mode, the stylus can send the first downlink signals including at least position information and/or tilt information of the stylus to the first paired touch display device.

[0072] After receiving the first ACK signal, the first paired touch display device can enter into the stylus scan mode to scan for the first downlink signals including at least the position information and/or tilt information of the stylus. Accordingly, the first bidirectional communication can be set up between the communication module of the stylus and the first TIC of the first paired touch display device, so that the first paired touch display device can start receiving a touch input from the stylus.

[0073] In an embodiment, the first TIC of the first paired touch display device can continuously send the first uplink code to the communication module of the stylus, so that the stylus can ensure that the first bidirectional communication is still effective (or valid) after the stylus enters into the stylus operation mode. When the stylus is not able to receive the first uplink code, the stylus can run a first timer to count for a first timeout period. If the first timeout period is greater than a first timeout threshold (e.g., 250ms), the stylus can exit the stylus operation mode. After the stylus exits from the stylus operation mode, the stylus can enter back into the scan mode to scan for uplink codes.

[0074] In an embodiment, the communication module of the stylus can continuously send the first downlink signal with the first downlink frequency to the first TIC of the first paired touch display device, so that the first paired touch display device can ensure that the first bidirectional communication is still effective after the first paired touch display device enters into the stylus scan mode. When the first paired touch display device is not able to receive the first downlink signal, the first paired touch display device can run a second timer to count for a second timeout period. If the second timeout period is greater than a second timeout threshold (e.g., 250ms), the first paired touch display device can exit the stylus scan mode and enter back into a finger scan mode to scan for a touch input from a finger (or another body part) of a user.

[0075] For example, if the stylus is moved away from the first paired touch display device, the first distance between the stylus and the first paired touch display device can be out of the first bidirectional communication range. The stylus is not able to receive the first uplink code and the first timeout period is greater than the first timeout threshold, the stylus can exit the stylus operation mode and enter back into the scan mode. The first paired touch display device is not able to receive the first downlink signal and the second timeout period is greater than the second timeout threshold, the first paired touch display device can exit the stylus scan mode and enter back into the finger scan mode.

[0076] In an embodiment, a second paired touch display device (e.g., the touch display device C 111) of the multiple paired touch display devices in the touch sensing system can be paired to the stylus via a second Bluetooth connection. In response to the success of the second Bluetooth connection, the stylus can send, to the second paired touch display device and via the second Bluetooth connection, a second uplink code (e.g., 011). In response to receiving the second uplink code, the second paired touch display device can start sending the second uplink code.

[0077] In an embodiment, the stylus can be moved from the first paired touch display device to the second paired touch display device. If the stylus is close enough (in proximity) to the second paired touch display device, the first distance can be out of the first communication range, and a second distance between the stylus and the second paired touch display device can be within a second communication range (e.g., within 3cm) of a second bidirectional communication. Accordingly, the stylus can receive, from the second paired touch display device, the second uplink code that is assigned to the second paired touch display device. The second bidirectional communication can be set up between a second TIC of the second paired touch display device and the communication module of the stylus. The second uplink code can be sent in a second uplink signal from the second TIC of the second paired touch display device to the communication module of the stylus. In addition to the second uplink code, the second uplink signal can include a second beacon that is used by the stylus to perform a second clock synchronization to synchronize the stylus clock to a second TIC clock of the second TIC of the second paired touch display device.

[0078] After performing the second clock synchronization, the stylus can obtain a second downlink frequency for sending second downlink signals. Further, the stylus can send back a second ACK signal to the second paired touch display device, and enter into the stylus operation mode. The second ACK signal can be sent in one of the second downlink signals with the second downlink frequency from the communication module of the stylus to the second TIC of the second paired touch display device. In the stylus operation mode, the stylus can send the second downlink signals including at least the position information and/or tilt information of the stylus to the second paired touch display device.

[0079] After receiving the second ACK signal, the second paired touch display device can enter into the stylus scan mode to scan for the second downlink signals including at least the position information and/or tilt information of the stylus. Accordingly, the second bidirectional communication can be set up between the communication module of the stylus and the second TIC of the second paired touch display device, so that the second paired touch display device can start receiving a touch input from the stylus.

[0080] In an embodiment, the stylus can obtain a number of previously paired touch display devices, for example, by counting a number of device identities (e.g., MAC address) of the previously paired touch display devices stored in the stylus. When a number of the currently paired touch display devices is less than the number of the previously paired touch display devices, the stylus can scan for a device that was previously paired and currently unpaired to the stylus. For example, the stylus can send a Bluetooth connection request to a touch display device that has a device identity stored in the stylus and is not currently paired with the stylus. Once the touch display device succeeds to respond to and pair with the stylus, the stylus can assign an uplink code to the newly paired touch display device, so that the newly paired touch display device can receive a touch input from the stylus after a bidirectional communication is set up between the stylus and the newly paired touch display device.

[0081] In an example, all of the touch display devices 110-112 in FIG. 1 were previously paired to the stylus 120 so that the device identities of the touch display devices 110-112 are stored in the stylus 120. When the stylus 120 initially sends a Bluetooth connection request to each of the touch display devices 110-112, the touch display devices 110-111 succeed to respond to and pair with the stylus 120, while the touch display device B 112 fails to respond to and pair with the stylus 120. Since the number of the currently paired touch display devices is less than the number of the stored device identities, the stylus 120 can scan for the response of the touch display device B 112 by continuously sending the Bluetooth connection request to the touch display device B 112. Once the touch display device B 112 succeeds to respond to and pair with the stylus 120, the stylus 120 can assign an uplink code (e.g., 010) to the touch display device B 112, so that the touch display device B 112 can receive a touch input from the stylus 120 after a bidirectional communication is set up between the stylus 120 and the touch display device B 112.

[0082] It is noted that a reason why the touch display device B 112 fails to respond to and pair with the stylus 120 is not limited in this disclosure. In an example, the Bluetooth function of the touch display device B 112 is not turned on when the stylus 120 initially sends out the Bluetooth requests to all the touch display devices 110-112. In an example, the Bluetooth signal quality of the touch display device B 112 may not be good enough to respond to and pair with the stylus 120, when the stylus 120 initially sends out the Bluetooth requests to all the touch display devices 110-112.

[0083] FIG. 2 shows an exemplary procedure 200 according to embodiments of the disclosure. Tn the procedure 200, stylus can be the stylus 120 in FIG. 1 , and devices A and B can be the touch display devices 110 and 112 in FIG. 1, respectively. Both the devices A and B are within a Bluetooth connection range (e.g., around 10m) of the stylus.

[0084] At step S210, the stylus can be at an idle status, and Bluetooth functions of the devices A and B can be turned on and off, respectively.

[0085] At step S21 I, the stylus can awake, for example, by a gravity sensor (G-sensor).

The stylus can check stored device identities (e.g., MAC addresses) of devices that were previously paired to the stylus, for example, via BLE connections. The stylus can send BLE connection requests to the previously paired devices that have the device identities stored in the stylus. Since the Bluetooth function of the device B is turned off, the device B does not respond to the BLE connection request sent from the stylus. The Bluetooth function of the device A is turned on, and the device A can receive the BLE connection request and start a BLE connection with the stylus.

[0086] It is noted that the procedure 200 can include one or more other devices which the stylus can send the BLE connection requests to, in addition to the devices A and B. [0087] At step S212, the device A can send back to the stylus an ACK signal via the BLE connection, indicating that the BLE connection between the device A and the stylus succeeds. The stylus can create a list of currently connected devices including the device A. In an example, the currently connected devices can include one or more other devices, in addition to the device A.

[0088] At step S213, the stylus can assign a different uplink code to each currently connected device, for example, via the BLE connection between the stylus and the respective currently connected device. Each currently connected device can receive the corresponding assigned uplink code and start sending the corresponding assigned uplink code, for example, by a TIC of the respective currently connected device. For example, the device A can receive an uplink code (e.g., 001) and then start sending the uplink code by a TIC (e.g., TIC 150) of the device A.

[0089] At step S214, the stylus can enter into a scan mode to scan for the assigned uplink codes.

[0090] At step S215, the stylus can determine whether one of the assigned uplink codes is received by the stylus. In an example, when a distance between the stylus and the device A is within a communication range of a bidirectional communication between a communication module (e.g., communication module 123) of the stylus and the TIC of the device A, the stylus can receive an uplink code assigned to the device A. The uplink code can be sent in an uplink signal from the TIC of the device A to the communication module of the stylus. The uplink signal can include a beacon for clock synchronization between the TIC of the device A and the communication module of the stylus. Based on the beacon, the stylus can obtain a downlink frequency for sending downlink signals. After the clock synchronization, the stylus can send an ACK signal to the device A and enter into a stylus operation mode. The ACK signal can be sent in a downlink signal with the obtained downlink signal frequency from the communication module of the stylus to the TIC of the device A. After receiving the ACK signal, the device A can enter into a stylus scan mode to scan for other downlink signals sent from the stylus. The other downlink signal can include at least position information and/or tilt information of the stylus. [0091] At step S216, the stylus can determine whether the uplink code assigned to the device A is continuously received. If the stylus is not able to receive the uplink code assigned to the device A, the stylus can run a first timer to count for a first timeout period.

[0092] At step S217, the stylus can determine whether the first timeout period is greater than a first timeout threshold (e.g., 250ms). If the first timeout period is greater than the first timeout threshold, the stylus can exit the stylus operation mode and enter back into the scan mode to scan for the assigned uplink codes.

[0093] At step S218, the device A can determine whether the downlink signal sent from the stylus is continuously received. If the device A is not able to receive the downlink signal sent from the stylus, the device A can run a second timer to count for a second timeout period.

[0094] At step S219, the device A can determine whether the second timeout period is greater than a second timeout threshold (e.g., 250ms). If the second timeout period is greater than the second timeout threshold, the device A can exit the stylus scan mode and enter back into a finger scan mode to scan for a touch input from a finger (or another body part) of a user.

[0095] At step S220, the Bluetooth function of the device B can be turned on.

[0096] At step S221, the stylus can determine whether a number of currently connected devices is less than a number of previously connected devices. If the number of currently connected devices is less than the number of previously connected devices, the stylus can scan for currently unpaired devices by sending a BLE connection request to one of the previously connected devices that is not currently connected to the stylus. For example, the device B is such a device. That is, the device B was previously connected to and is not currently connected to the stylus. Since the Bluetooth function of the device B is now turned on, the device B can receive the BLE connection request and start the BLE connection.

[0097] At step S222, the device B can succeed to connect to the stylus via the BLE connection and send an ACK signal to the stylus. After receiving the ACK signal, the stylus can update the list of the currently connected devices to include the newly connected device B.

[0098] At step S223, the device B can assign an uplink code (e.g., 010) to the device B. The uplink code can be sent, for example, via the BLE connection between the stylus and the newly connected device B. The device B can receive the assigned uplink code and start sending the assigned uplink code, for example, by a TIC of the device B. [0099] In an embodiment, when the stylus receives the uplink code assigned to the device B, the stylus can enter into the stylus operation mode and send an ACK signal to the device B. After receiving the ACK signal from the stylus, the device B can enter into the stylus scan mode and start receiving a touch input from the stylus.

[0100] FIG. 3 shows an exemplary timing diagram 300 according to embodiments of the disclosure. In the timing diagram 300, a stylus (e.g., stylus 120) can pair with a touch display device (e.g., touch display device 110) via a BLE connection for example. The stylus can assign an uplink code to the device via the BLE connection. Then, when the stylus moves close to the device, and a distance between the stylus and the device is within a communication range of a bidirectional communication, the bidirectional communication can be set up between a communication module (e.g., communication module 123) of the stylus and a TIC (e.g., TIC 150) of the device. After the bidirectional communication is set up, the device can receive a touch input from the stylus. A detailed procedure can be described as follows.

[0101] In a first time period T1 of the timing diagram 300, the device can send, to the stylus, the uplink code assigned by the stylus to the device. However, the device fails to receive, from the stylus, a first ACK signal, so that the device can maintain a finger scan mode to scan for a touch input from a finger (or another body part) of a user. The uplink code can be sent in a first uplink signal from the TIC of the device to the communication module of the stylus, for example, via a capacitive coupling between a touch panel (e.g., touch panel 132) of the device and an electrode (e.g., electrode 124) of the stylus. The first ACK signal can be sent in a first downlink signal from the communication module of the stylus to the TIC of the device, for example, via the capacitive coupling between the touch panel of the device and the electrode of the stylus.

[0102] Specifically, at a time slot TSM, the stylus receives, from the device, the first uplink signal including the uplink code assigned to the device. In addition to the uplink code, the first uplink signal can include a first beacon for clock synchronization between the stylus and the device. Based on the received first beacon, the stylus can determine time slots for a plurality of first downlink signals that include the first ACK signal and first position information (POS) of the stylus. At a time slot TSI.₂, the stylus sends, to the device, the first downlink signal including the first ACK signal. However, the device fails to receive the first downlink signal including the first ACK signal, although the device reserves the time slot TSI_₂ for receiving the first downlink signal including the first ACK signal. Accordingly, the device can be in the finger scan mode in the remaining time slots of the first time period Tl.

[0103] In a second time period T2 of the timing diagram 300, the device can further send, to the stylus, the uplink code assigned by the stylus to the device. The device succeeds to receive, from the stylus, a second ACK signal, so that the device can enter into a stylus scan mode to scan for a touch input from the stylus. The uplink code can be sent in a second uplink signal from the TIC of the device to the communication module of the stylus, for example, via the capacitive coupling between the touch panel of the device and the electrode of the stylus. The second ACK signal can be sent in a second downlink signal from the communication module of the stylus to the TIC of the device, for example, via the capacitive coupling between the touch panel of the device and the electrode of the stylus.

[0104] Specifically, at a time slot TS_2. the stylus receives, from the device, the second uplink signal including the uplink code assigned to the device. In addition to the uplink code, the second uplink signal can include a second beacon for clock synchronization between the stylus and the device. Based on the received second beacon, the stylus can determine time slots for a plurality of second downlink signals that include the second ACK signal and second position information (POS) of the stylus. At a time slot TS₂.2, the stylus sends, to the device, the second downlink signal including the second ACK signal, and the device succeeds to receive the second downlink signal including the second ACK signal. After receiving the second downlink signal including the second ACK signal, the device enters into the stylus scan mode so that the device can receive the second downlink signals including the second position information of the stylus in the remaining time slots (e.g., time slots from TS₂.3 to TS₂.e) of the second time period T2.

[0105] In a third time period T3 of the timing diagram 300, the device can further send, to the stylus, a third uplink signal including the uplink code assigned by the stylus to the device. Further, the device can receive, from the stylus, a plurality of third downlink signals including third position information of the stylus, so that the device can maintain the stylus scan mode to scan for a touch input from the stylus. It is noted that the stylus (or the device) may not need to send (or receive) an ACK signal during the third time period T3 because, during the second time period T2, a bidirectional communication has been set up between the stylus and the device.

[0106] According to embodiments of the disclosure, a stylus (e.g., stylus 120) can pair with each of multiple touch display devices in a touch sensing system (e.g., touch sensing system 100) via a respective Bluetooth connection when the Bluetooth functions of the multiple touch display devices are turned on and the multiple touch display devices are within the Bluetooth connection range of the stylus. Clock information of the stylus can be sent from the stylus to each paired touch display device via the respective Bluetooth connection, so that each paired touch display device can synchronize a TIC clock of a TIC of the respective paired touch display device with the stylus clock. Each paired touch display device can send back to the stylus a downlink frequency that is used for the respective paired touch display device to receive downlink signals from the stylus. After receiving the respective downlink frequency, the stylus can assign a different time slot with the respective downlink frequency to each paired touch display device via the respective Bluetooth connection. Then, the stylus can enter into an advertising mode to send the downlink signals at the assigned time slots. After receiving the respective assigned time slot, each paired touch display device can start scanning for the downlink signals at the respective assigned time slot and keep informing the stylus of the respective downlink frequency.

[0107] In an embodiment, a first paired touch display device (e.g., the touch display device A 110) of the multiple paired touch display devices can be paired to the stylus via a first Bluetooth connection. Tn response to the success of the first Bluetooth connection, the first paired touch display device can send, to the stylus and via the first Bluetooth connection, a first downlink frequency that is used for the first paired touch display device to receive first downlink signals from the stylus. In response to receiving the first downlink frequency, the stylus can assign a first time slot with the first downlink frequency to the first paired touch display device via the first Bluetooth connection.

[0108] In an embodiment, if the stylus is moved close to the first paired touch display device, a first distance between the stylus and the first paired touch display device can be within a first communication range (e.g., within 3cm) of a first bidirectional communication between a communication module (e.g., communication module 123) of the stylus and a first TIC (e.g., TIC 150) of the first paired touch display device. The first paired touch display device can receive, from the stylus and via the first bidirectional communication, one of the first downlink signals with the first downlink frequency at the first time slot that is assigned by the stylus to the first paired touch display device. The one of the first downlink signals can be received by the first TIC of the first paired touch display device from the communication module of the stylus. [0109] After receiving the one of the first downlink signals, the first paired touch display device can send back a first ACK signal to the stylus and enter into the stylus scan mode to scan for other first downlink signals including at least position information and/or tilt information of the stylus. The first ACK signal can be sent via the first Bluetooth connection.

[0110] After receiving the first ACK signal, the stylus can enter into the stylus operation mode and send the first downlink signals including at least the position information and/or tilt information of the stylus to the first paired touch display device. Accordingly, the first bidirectional communication can be set up between the communication module of the stylus and the first TIC of the first paired touch display device, so that the first paired touch display device can start receiving a touch input from the stylus.

[OHl] In an embodiment, the communication module of the stylus can continuously send the first downlink signals with the first downlink frequency to the first TIC of the first paired touch display device, so that the first paired touch display device can ensure that the first bidirectional communication is still effective after the first paired touch display device enters into the stylus scan mode. When the first paired touch display device is not able to receive the first downlink signals, the first paired touch display device can run a timer to count for a timeout period. If the timeout period is greater than a timeout threshold (e g., 250ms), the first paired touch display device can exit the stylus scan mode and enter back into a finger scan mode to scan for a touch input from a finger (or another body part) of a user. The first paired touch display device can further inform the stylus to exit the stylus operation mode via the first Bluetooth connection between the first paired touch display device and the stylus. After exiting the stylus operation mode, the stylus can enter back into the advertising mode to send downlink signals at the assigned time slots.

[0112] For example, if the stylus is moved away from the first paired touch display device, the first distance between the stylus and the first paired touch display device can be out of the first bidirectional communication range. The first paired touch display device is not able to receive the first downlink signals and the timeout period is greater than the timeout threshold, the first paired touch display device can exit the stylus scan mode and enter back into the finger scan mode. The first paired touch display device can inform the stylus to exit the stylus operation mode via the first Bluetooth connection. After exiting the stylus operation mode, the stylus can enter back into the advertising mode to send downlink signals at the assigned time slots.

[0113] In an embodiment, a second paired touch display device (e.g., the touch display device C 111) of the multiple paired touch display devices in the touch sensing system can be paired to the stylus via a second Bluetooth connection. In response to the success of the second Bluetooth connection, the second paired touch display device can send, to the stylus and via the second Bluetooth connection, a second downlink frequency that is used for the second paired touch display device to receive second downlink signals from the stylus. In response to receiving the second downlink frequency, the stylus can assign a second time slot with the second downlink frequency to the second paired touch display device via the second Bluetooth connection. The second time slot can be different from the first time slot.

[0114] In an embodiment, the stylus can be moved from the first paired touch display device to the second paired touch display device. If the stylus is close enough to the second paired touch display device, the first distance can be out of the first communication range, and a second distance between the stylus and the second paired touch display device can be within a second communication range (e.g., within 3cm) of a second bidirectional communication. Accordingly, the second paired touch display device can receive, from the stylus and via the second bidirectional communication, one of the second downlink signals with the second downlink frequency at the second time slot that is assigned by the stylus to the second paired touch display device. The second bidirectional communication can be set up between a second TIC of the second paired touch display device and the communication module of the stylus. The one of the second downlink signals can be received by the second TIC of the second paired touch display device from the communication module of the stylus.

[0115] After receiving the one of the second downlink signals, the second paired touch display device can send back a second ACK signal to the stylus and enter into the stylus scan mode to scan for other second downlink signals including at least the position information and/or tilt information of the stylus. The second ACK signal can be sent via the second Bluetooth connection.

[0116] After receiving the second ACK signal, the stylus can enter into the stylus operation mode and send the second downlink signals including at least the position information and/or tilt information of the stylus to the second paired touch display device. Accordingly, the second bidirectional communication can be set up between the communication module of the stylus and the second TIC of the second paired touch display device, so that the second paired touch display device can start receiving a touch input from the stylus.

[0117] In an embodiment, the stylus can obtain a number of previously connected touch display devices, for example, by counting a number of device identities (e.g., MAC address) of the previously paired touch display device stored in the stylus. When a number of the currently paired touch display devices is less than a number of the previously paired touch display devices, the stylus can scan for a device that was previously paired and currently unpaired to the stylus. For example, the stylus can send a Bluetooth connection request to a touch display device that has a device identity stored in the stylus and is not currently paired with the stylus. If the touch display device can succeed to respond to and pair with the stylus, the newly paired touch display device can synchronize a TIC clock of a TIC of the newly paired touch display device to the stylus clock and send to the stylus a downlink frequency that is used for the newly paired touch display device to receive downlink signals from the stylus.

[0118] In response to receiving the downlink frequency, the stylus can assign a time slot with the downlink frequency to the newly paired touch display device, so that the newly paired touch display device can scan for the downlink signals at the assigned time slot. The time slot assigned to the newly paired touch display device can be different from the time slots assigned to other paired touch display devices. Further, the stylus can update the list of the currently connected devices to include the newly paired touch display device. In an example, assigning the time slot to the newly paired touch display device can enable the stylus to update the time slots for the other paired touch display devices and to assign the updated time slots to the other paired touch display devices. In addition, the newly paired touch display device can keep informing the stylus of the downlink frequency.

[0119] In an example, all of the touch display devices 110-112 in FIG. 1 were previously paired to the stylus 120 so that the device identities of the touch display devices 110-112 are stored in the stylus 120. When the stylus 120 initially sends a Bluetooth connection request to each of the touch display devices 110-112, the touch display devices 110-111 succeed to respond to and pair with the stylus 120, while the touch display device B 112 fails to respond to and pair with the stylus 120. Since the number of the currently paired touch display devices is less than the number of the stored device identities, the stylus 120 can scan for the response of the touch display device B 112 by continuously sending the Bluetooth connection request to the touch display device B 112. Once the touch display device B 112 succeeds to respond to and pair with the stylus 120, the stylus 120 can assign a time slot to the touch display device B 112, so that the touch display device B 112 can scan for a downlink signal at the assigned time slot.

[0120] It is noted that a reason that the touch display device B 112 fails to respond to and pair with the stylus 120 is not limited in this disclosure. In an example, the Bluetooth function of the touch display device B 112 is not turned on when the stylus 120 initially sends out the Bluetooth requests to all the touch display devices 110-112. In an example, the Bluetooth signal quality of the touch display device B 112 is not good enough to respond to and pair with the stylus 120 when the stylus 120 initially sends out the Bluetooth requests to all the touch display devices 110-112.

[0121] FIG. 4 shows an exemplary procedure 400 according to embodiments of the disclosure. In the procedure 400, stylus can be the stylus 120 in FIG. 1, and devices A and B can be the touch display devices 110 and 112 in FIG. 1, respectively. Both the devices A and B are within a Bluetooth connection range (e.g., around 10m) of the stylus.

[0122] At step S410, the stylus can be at an idle status, and Bluetooth functions of the devices A and B can be turned on and off, respectively.

[0123] At step S411, the stylus can be awake, for example, by a gravity sensor (G- sensor). The stylus can check stored device identities (e.g., MAC addresses) of devices that were previously paired to the stylus, for example, via BLE connections. The stylus can send BLE connection requests to the previously paired devices that have the device identities stored in the stylus. Since the Bluetooth function of the device B is turned off, the device B does not respond to the BLE connection request of the stylus. The Bluetooth function of the device A is turned on, and the device A can receive the BLE connection request and start a BLE connection with the stylus.

[0124] It is noted that the procedure 400 can include one or more other devices which the stylus can send the BLE connection requests to, in addition to the devices A and B.

[0125] At step S412, the device A can send back an ACK signal to the stylus and the BLE connection between the device A and the stylus succeeds. Based on a beacon included in the BLE connection, the device A can synchronize a TIC clock of a TIC (e.g., TIC 150) of the device A to the stylus clock. Via the BLE connection, the device A can send to the stylus a downlink frequency that is used for the device A to receive downlink signals from the stylus. The stylus can create a list of currently connected devices including the device A. In an example, the currently connected devices can include one or more other devices, in addition to the device A.

[0126] At step S413, the stylus can assign a different time slot with the corresponding downlink frequency to each currently connected device, for example, via the BLE connection between the stylus and the respective currently connected device. Each currently connected device can receive the corresponding assigned time slot and start scanning for the downlink signals at the corresponding assigned time slot, for example, by a TIC of the respective currently connected device. For example, the device A can receive first a time slot and then start scanning for the downlink signals at the first time slot. The device A can keep informing the stylus of the downlink frequency that is used for the device A to receive the downlink signals.

[0127] At step S414, the stylus can enter into an advertising mode to send the downlink signals.

[0128] At step S415, the device A can determine whether a downlink signal is received at the assigned first time slot. In an example, when a distance between the stylus and the device A is within a communication range of a bidirectional communication between a communication module (e.g., communication module 123) of the stylus and the TIC of the device A, the device A can receive the downlink signal from the stylus at the assigned first time slot. The downlink signal can be received by the TIC of the device A from the communication module of the stylus. The device A can send back to the stylus an ACK signal via the Bluetooth connection and enter into a stylus scan mode. After receiving the ACK signal, the stylus can enter into a stylus operation mode to send the downlink signal including at least position information and/or tilt information of the stylus.

[0129] At step S416, the device A can determine whether the downlink signal sent from the stylus is continuously received. If the device A is not able to receive the downlink signal sent from the stylus, the device A can run a timer to count for a timeout period. Then, the device A can determine whether the timeout period is greater than a timeout threshold (e g., 250ms). If the timeout period is greater than the timeout threshold, the device A can exit the stylus scan mode and enter back into a finger scan mode to scan for a touch input from a finger (or another body part) of a user. The device A can inform the stylus to exit the stylus operation mode, for example, by sending an exit indication to the stylus via the Bluetooth connection. After receiving the exit indication, the stylus can exit the stylus operation mode and enter back into the advertising mode.

[0130] At step S420, the Bluetooth function of the device B can be turned on.

[0131] At step S421, the stylus can determine whether a number of currently connected devices is less than a number of previously connected devices. If the number of currently connected devices is less than the number of previously connected devices, the stylus can scan for currently unpaired devices by sending a BLE connection request to one of the previously connected devices that is not currently connected to the stylus. For example, the device B is such a device. That is, the device B was previously connected to and is not currently connected to the stylus. Since the Bluetooth function of the device B is now turned on, the device B can receive the BLE connection request and start the BLE connection.

[0132] At step S422, the device B can succeed to connect to the stylus via the BLE connection. The device B can synchronize a TIC clock of a TIC of the device B to the stylus clock and send back to the stylus a downlink frequency that is used for the device B to receive downlink signals from the stylus. After receiving the downlink frequency, the stylus can update the list of the currently connected devices to include the newly connected device B.

[0133] At step S423, the stylus can assign a second time slot with the corresponding downlink frequency to the device B. The second time slot can be sent, for example, via the BLE connection between the stylus and the newly connected device B. After receiving the second time slot, the device B can start scanning for the downlink signals at the assigned second time slot, for example, by the TIC of the device B. In an example, assigning the second time slot to the newly paired device B can enable the stylus to update the time slots for the other paired devices and to assign the updated time slots to the other paired devices. In addition, the newly paired device B can keep informing the stylus of the downlink frequency.

[0134] In an embodiment, when the device B receives the downlink at the assigned time slot from the stylus, the device B can send an ACK signal to the stylus and enter into the stylus scan mode to start receiving a touch input from the stylus. After receiving the ACK signal from the device B, the stylus can enter into the stylus operation mode.

[0135] FIG. 5 shows an exemplary timing diagram 500 according to embodiments of the disclosure. In the timing diagram 500, a stylus (e.g., stylus 120) can pair with a touch display device (e.g., touch display devices 110) via a Bluetooth connection for example. A TIC clock of a TIC (e.g., TIC 150) of the touch display device can be synchronized to a stylus clock of the stylus based on a beacon included in the Bluetooth connection. The stylus can assign a time slot to the touch display device via the Bluetooth connection. In the timing diagram 500, the time slot is assigned to have a time difference (or time delay) of tsl from the time slot for transmission of Bluetooth packages between the stylus and the touch display device. Then, the touch display device can scan for downlink signals from the stylus at the assigned time slot.

[0136] Specifically, the timing diagram 500 includes two sub-diagrams 501-502, which represent the stylus clock and the TIC clock of the touch display device, respectively. Time slots 510-511 in each clock period are used for transmission of Bluetooth packages between the stylus and the touch display device, and thus are aligned to each other. Time slots 520-521 in each clock period are the assigned time slots used for transmission of downlink signals between the stylus and the touch display device, and thus are aligned to each other.

[0137] In a first time period Tl, the stylus and the touch display device are far away from each other so that the touch display device is not able to receive the downlink signal at the assigned time slot 521. Accordingly, the touch display device can maintain a finger scan mode to scan for a touch input from a finger (or another body part) of a user.

[0138] In a second time period T2, the stylus and the touch display device are close enough to each other so that the touch display device can receive the downlink signal at the assigned time slot 521, for example, via a capacitive coupling between an electrode (e.g., electrode 124) of the stylus and a touchscreen (e.g., touchscreen 130) of the touch display device. After receiving the downlink signal, the touch display device can change from the finger scan mode to a stylus scan mode to scan for a touch input from the stylus.

[0139] In a third time period T3, the touch display device can send back an ACK signal to the stylus via the Bluetooth connection to inform the stylus to enter a stylus operation mode. After receiving the ACK signal, the stylus can enter into the stylus operation mode and send downlink signals including at least position information and/or tilt information of the stylus to the touch display device. Since the touch display device is in the stylus scan mode and the clock synchronization between the touch display device and the stylus is done, a bidirectional communication between the touch display device and the stylus can be set up, and the touch display device is able to receive the downlink signals including at least the position information and/or tilt information of the stylus.

[0140] FIG. 6 shows an exemplary timing diagram 600 according to embodiments of the disclosure. In the timing diagram 600, a stylus (e.g., stylus 120) can pair with two touch display devices A and C (e.g., touch display devices 110 and 111) via Bluetooth connections for example. The stylus can send the Bluetooth packages to the devices A and C at a same time slot 610. The stylus can assign a different time slot to each device via the respective Bluetooth connection. Then, each device can scan for downlink signals at the respective assigned time slot.

[0141] Specifically, the timing diagram 600 includes three sub-diagrams 601-603, which represent the stylus clock and TIC clocks of the devices A and C, respectively. Before time Tl, the stylus can be in an idle status, and each of the devices A and C can be in a finger scan mode. At time Tl, the stylus can be awake and send Bluetooth packages to the devices A and C in order to pair with the devices A and C. Time slots 610-612 are used for Bluetooth connections between the stylus and the devices A and C, and thus are aligned to each other in the timing diagram 600. Once the Bluetooth connections succeed, the TIC clocks of the devices A and C can be synchronized to the stylus clock. Accordingly, from time T2, the TIC clocks of the devices A and C in the sub-diagrams 602-603 are synchronized to the stylus clock in the subdiagram 601.

[0142] The devices A and C can use time slots 620-621 to scan for downlink signals from the stylus, respectively. Before the Bluetooth connection (e.g., time Tl), the time slot 620 (or 621) can be set at a default position (e.g., at the front) of a clock period of the TIC clock. Via the Bluetooth connections, the stylus can assign time slots 630-631 to the devices A and C, respectively. Time difference from the time slots 630-631 to the time slot 610 for Bluetooth package can be set as tsl and ts2, respectively. Accordingly, from time T2, the time slots 620- 621 are aligned to the assigned time slots 630-631, respectively, and are delayed with tsl and ts2 from the time slots 611-612, respectively. The devices A and C can respectively scan for the downlink signals from the stylus at the newly aligned time slots 620-621, which are respectively aligned to the time slots 630-631.

[0143] FIG. 7 shows an exemplary timing diagram 700 according to embodiments of the disclosure. In the timing diagram 700, a stylus (e.g., stylus 120) can pair with two touch display devices A and C (e.g., touch display devices 110 and 111) via Bluetooth connections for example. The stylus can send Bluetooth packages to the devices A and C at different time slots 710-711, respectively. The stylus can assign different time slots 730-731 to the devices A and C via the Bluetooth connections. The time slots 730-731 can be delayed relative to the time slots 710-711, respectively. Then, each device can scan for downlink signals at the respective assigned time slot.

[0144] Specifically, the timing diagram 700 includes three sub-diagrams 701-703, which represent the stylus clock and TIC clocks of the devices A and C, respectively. Before time Tl, the stylus can be in an idle status, and each of the devices A and C can be in a finger scan mode. At time Tl, the stylus can be awake and send a first Bluetooth package to the device A in order to pair with the device A. A time slot 712 can be used for transmission of the first Bluetooth package between the device A and the stylus, and thus be aligned to the time slot 710. Once the Bluetooth connection between the device A and the stylus succeeds, the TIC clock of the device A can be synchronized to the stylus clock based on the time slot 712 being aligned to the time slot 710.

[0145] Similarly, at time T2, the stylus can send a second Bluetooth package to the device C in order to pair with the device C. A time slot 713 can be used for transmission of the second Bluetooth package between the device C and the stylus, and thus be aligned to the time slot 711. Once the Bluetooth connection between the device C and the stylus succeeds, the TIC clock of the device C can be synchronized to the stylus clock based on the time slot 713 being aligned to the time slot 711.

[0146] The devices A and C can use time slots 720-721 to scan for downlink signals from the stylus, respectively. Before the Bluetooth connection (e.g., before time Tl or T2), the time slot 720 (or 721) can be set at a default position (e.g., at the front) of a clock period of the TIC clock. Via the Bluetooth connections, the stylus can assign time slots 730-731 to the devices A and C, respectively. Time difference from the time slots 730-731 to the time slots 710-711 can be set as tsl and ts2, respectively. Accordingly, the time slot 720-721 are aligned to the assigned time slots 730-731 from time T3 and T4, respectively. The devices A and C can respectively scan for the downlink signals from the stylus at the newly aligned time slots 720- 721, which are respectively aligned to the time slots 730-731.

[0147] It is noted that the information included in the downlink signals is not limited to the position information and/or tilt information of the stylus in this disclosure. [0148] In an embodiment, when a user wants to have a device paired to a first stylus to work with a second stylus, the user has to clear the first stylus information in the device before pairing the device to the second stylus.

[0149] Aspects of the disclosure provide a method for a stylus (e.g., stylus 120) to cooperate with one or more touch display devices (e.g., touch display devices 110-112). The method includes assigning, by the stylus, a first uplink code to a first touch display device (e.g., touch display device 110) of the one or more touch display devices. In response to receiving, by the stylus and from touch driving circuitry (e.g., TIC 150) of the first touch display device, a first uplink signal including the first uplink code, the method includes sending, from the stylus to the touch driving circuitry of the first touch display device, a first ACK signal to inform the first touch display device to be ready for receiving a downlink signal from the stylus. The method further includes sending, from the stylus to the touch driving circuitry of the first touch display device, the downlink signal including at least position information or tilt information of the stylus.

[0150] In an embodiment, the method includes establishing, by the stylus, a first Bluetooth connection with the first touch display device, wherein the first uplink code is assigned by the stylus via the first Bluetooth connection to the first touch display device. Tn example, when a Bluetooth function of the first touch display device is turned on and the stylus is within a Bluetooth connection range (e.g., around 10m) of the first touch display device, the method includes sending a Bluetooth connection request from the stylus to the first touch display device, receiving a Bluetooth ACK signal by the stylus from the first touch display device, and pairing by the stylus with the first touch display device to establish the first Bluetooth connection.

[0151] In an embodiment, the method includes establishing, by the stylus, a second Bluetooth connection with a second touch display device (e.g., touch display device 111) of the one or more touch display devices, assigning, by the stylus and via the second Bluetooth connection, a second uplink code to the second touch display device, and scanning for, by the stylus, the second uplink code. The second uplink code is different from the first uplink code.

[0152] In an embodiment, the first uplink signal includes a beacon for clock synchronization between the stylus and the touch driving circuitry of the first touch display device, and the method includes performing, by the stylus, the clock synchronization based on the beacon included in the first uplink signal.

[0153] In an embodiment, the method includes, after sending the downlink signal, determining whether a second uplink signal including the first uplink code is received by the stylus from the touch driving circuitry of the first touch display device. In response to determining that the second uplink signal including the first uplink code is not received by the stylus, the method further includes running a timer to count a timeout period and stop sending the downlink signal based on the timeout period being greater than a timeout threshold.

[0154] In an embodiment, in response to not receiving the first uplink signal including the first uplink code, the method includes determining whether there is a third touch display device (e.g., touch display device 112) of the one or more touch display devices that was previously and is not currently Bluetooth connected to the stylus. The method includes sending a Bluetooth connection request to the third touch display device based on a determination that there is the third touch display device that was previously and is not currently Bluetooth connected to the stylus.

[0155] In an embodiment, in response to receiving, by the stylus and from the third touch display device, a second ACK signal indicating that the Bluetooth connection request is received by the third touch display device and a third Bluetooth connection is established between the stylus and the third touch display device, the method includes updating, by the stylus, a list of connected devices to include the third touch display device, and assigning, by the stylus and via the third Bluetooth connection, a third uplink code to the third touch display device, the third uplink code being different from the first uplink code.

[0156] Aspects of the disclosure provide an apparatus (e.g., stylus 120). Processing circuitry (e.g., MCU 122) of the apparatus assigns a first uplink code to a first touch display device (e.g., touch display device 110) of one or more touch display devices (e.g., touch display devices 110-112). In response to receiving, from touch driving circuitry (e.g., TIC 150) of the first touch display device, a first uplink signal including the first uplink code, the processing circuitry sends, to the touch driving circuitry of the first touch display device, a first ACK signal to inform the first touch display device to be ready for receiving a downlink signal from the apparatus, and sends, to the touch driving circuitry of the first touch display device, the downlink signal including at least position information or tilt information of the apparatus. [0157] In an embodiment, the processing circuitry establishes a first Bluetooth connection with the first touch display device, wherein the first uplink code is assigned via the first Bluetooth connection to the first touch display device. In example, when a Bluetooth function of the first touch display device is turned on and the apparatus is within a Bluetooth connection range (e.g., around 10m) of the first touch display device, the processing circuitry sends a Bluetooth connection request to the first touch display device, receives a Bluetooth ACK signal from the first touch display device, and pairs with the first touch display device to establish the first Bluetooth connection.

[0158] In an embodiment, the processing circuitry establishes a second Bluetooth connection with a second touch display device (e.g., touch display device 111) of the one or more touch display devices, assigns, via the second Bluetooth connection, a second uplink code to the second touch display device, and scans for the second uplink code. The second uplink code is different from the first uplink code.

[0159] In an embodiment, the first uplink signal includes a beacon for clock synchronization between the apparatus and the touch driving circuitry of the first touch display device. The processing circuitry performs the clock synchronization based on the beacon included in the first uplink signal.

[0160] In an embodiment, after sending the downlink signal, the processing circuitry determines whether a second uplink signal including the first uplink code is received by the apparatus from the touch driving circuitry of the first touch display device. In response to determining that the second uplink signal including the first uplink code is not received by the apparatus, the processing circuitry runs a timer to count a timeout period, and stops sending the downlink signal based on the timeout period being greater than a timeout threshold.

[0161] In an embodiment, in response to not receiving the first uplink signal including the first uplink code, the processing circuitry determines whether there is a third touch display device (e.g., touch display device 112) of the one or more touch display devices that was previously and is not currently Bluetooth connected to the apparatus, and sends a Bluetooth connection request to the third touch display device based on a determination that there is the third touch display device that was previously and is not currently Bluetooth connected to the apparatus. [0162] In an embodiment, in response to receiving, from the third touch display device, a second ACK signal indicating that the Bluetooth connection request is received by the third touch display device and a third Bluetooth connection is established between the apparatus and the third touch display device, the processing circuitry updates a list of connected devices to include the third touch display device, and assigns, via the third Bluetooth connection, a third uplink code to the third touch display device, the third uplink code being different from the first uplink code.

[0163] Aspects of the disclosure provide a non-transitory computer-readable medium storing instructions which, when executed by an apparatus, cause the apparatus to perform: assigning a first uplink code to a first touch display device of one or more touch display devices; and in response to receiving, from touch driving circuitry of the first touch display device, a first uplink signal including the first uplink code, sending, to the touch driving circuitry of the first touch display device, a first acknowledge (ACK) signal to inform the first touch display device to be ready for receiving a downlink signal from the apparatus, and sending, to the touch driving circuitry of the first touch display device, the downlink signal including at least position information or tilt information of the apparatus.

[0164] Aspects of the disclosure provide a method for a stylus (e.g., stylus 120) to cooperate with one or more touch display devices (e.g., touch display devices 110-112). The method includes assigning, by the stylus, a first time slot to a first touch display device (e g., touch display device 110) of the one or more touch display devices, and sending, by the stylus, a first downlink signal at the first time slot. In response to receiving, by the stylus and from the first touch display device, a first ACK signal indicating that the first downlink signal is received by touch driving circuitry (e.g., TIC 150) of the first touch display device at the first time slot, the method includes sending, from the stylus to the touch driving circuitry of the first touch display device, a second downlink signal including at least position information or tilt information of the stylus.

[0165] In an embodiment, the method includes establishing, by the stylus, a first Bluetooth connection with the first touch display device, wherein the first time slot is assigned by the stylus via the first Bluetooth connection to the first touch display device, and the first ACK signal is received by the stylus via the first Bluetooth connection. In example, when a Bluetooth function of the first touch display device is turned on and the stylus is within a Bluetooth connection range (e.g., around 10m) of the first touch display device, the method includes sending a Bluetooth connection request from the stylus to the first touch display device, receiving a Bluetooth ACK signal by the stylus from the first touch display device, and pairing by the stylus with the first touch display device to establish the first Bluetooth connection.

[0166] In an embodiment, the first Bluetooth connection includes a beacon for clock synchronization between the stylus and the touch driving circuitry of the first touch display device. The processing circuitry performs the clock synchronization based on the beacon included in the first Bluetooth connection.

[0167] In an embodiment, the method includes establishing, by the stylus, a second Bluetooth connection with a second touch display device (e.g., touch display device 111) of the one or more touch display devices, assigning, by the stylus and via the second Bluetooth connection, a second time slot to the second touch display device, the second time slot being different from the first time slot, and sending, by the stylus, a third downlink signal at the second time slot.

[0168] In an embodiment, the method includes receiving, by the stylus and via the first Bluetooth connection, an indication to stop sending the second downlink signal.

[0169] In an embodiment, in response to not receiving the first ACK signal, the method includes determining whether there is a third touch display device (e.g., touch display device 112) of the one or more touch display devices that was previously and is not currently Bluetooth connected to the stylus, and sending a Bluetooth connection request to the third touch display device based on a determination that there is the third touch display device that was previously and is not currently Bluetooth connected to the stylus.

[0170] In an embodiment, in response to receiving, by the stylus and from the third touch display device, a second ACK signal indicating that the Bluetooth connection request is received by the third touch display device and a third Bluetooth connection is established between the stylus and the third touch display device, the method includes updating, by the stylus, a list of connected devices to include the third touch display device, assigning, by the stylus and via the third Bluetooth connection, a third time slot to the third touch display device, the third time slot being different from the first time slot or the second time slot, and sending, by the stylus, a fourth downlink signal at the third time slot. [0171] Aspects of the disclosure provide an apparatus (e.g., stylus 120). Processing circuitry (e.g., MCU 122) of the apparatus assigns a first time slot to a first touch display device (e.g., touch display device 110) of one or more touch display devices (e.g., touch display devices 110-112), and sends a first downlink signal at the first time slot. In response to receiving, from the first touch display device, a first ACK signal indicating that the first downlink signal is received by touch driving circuitry of the first touch display device at the first time slot, the processing circuitry sends, to the touch driving circuitry of the first touch display device, a second downlink signal including at least position information or tilt information of the apparatus.

[0172] In an embodiment, the processing circuitry establishes a first Bluetooth connection with the first touch display device, wherein the first time slot is assigned by the apparatus via the first Bluetooth connection to the first touch display device, and the first ACK signal is received by the apparatus via the first Bluetooth connection. In example, when a Bluetooth function of the first touch display device is turned on and the apparatus is within a Bluetooth connection range (e.g., around 10m) of the first touch display device, the processing circuitry sends a Bluetooth connection request to the first touch display device, receives a Bluetooth ACK signal from the first touch display device, and pairs with the first touch display device to establish the first Bluetooth connection.

[0173] In an embodiment, the first Bluetooth connection includes a beacon for clock synchronization between the apparatus and the touch driving circuitry of the first touch display device. The processing circuitry performs the clock synchronization based on the beacon included in the first Bluetooth connection.

[0174] In an embodiment, the processing circuitry sets up a second Bluetooth connection with a second touch display device (e.g., touch display device 111) of the one or more touch display devices, assigns, via the second Bluetooth connection, a second time slot to the second touch display device, the second time slot being different from the first time slot, and sends a third downlink signal at the second time slot.

[0175] In an embodiment, the processing circuitry receives, via the first Bluetooth connection, an indication to stop sending the second downlink signal.

[0176] In an embodiment, in response to not receiving the first ACK signal, the processing circuitry determines whether there is a third touch display device (e.g., touch display device 112) of the one or more touch display devices that was previously and is not currently Bluetooth connected to the apparatus, and sends a Bluetooth connection request to the third touch display device based on a determination that there is the third touch display device that was previously and is not currently Bluetooth connected to the apparatus.

[0177] In an embodiment, in response to receiving, from the third touch display device, a second ACK signal indicating that the Bluetooth connection request is received by the third touch display device and a third Bluetooth connection is established between the apparatus and the third touch display device, the processing circuitry updates a list of connected devices to include the third touch display device, assigns, via the third Bluetooth connection, a third time slot to the third touch display device, the third time slot being different from the first time slot or the second time slot, and sends a fourth downlink signal at the third time slot.

[0178] Aspects of the disclosure provide a non-transitory computer-readable medium storing instructions which, when executed by an apparatus, cause the apparatus to perform: assigning a first time slot to a first touch display device of one or more touch display devices; sending a first downlink signal at the first time slot; and in response to receiving, from the first touch display device, a first ACK signal indicating that the first downlink signal is received by touch driving circuitry of the first touch display device at the first time slot, sending, to the touch driving circuitry of the first touch display device, a second downlink signal including at least position information or tilt information of the apparatus.

[0179] The processes and functions described herein can be implemented as a computer program which, when executed by one or more processors (e.g., CPU 841 of computer system 800), can cause the one or more processors to perform the respective processes and functions. The computer program may be stored or distributed on a suitable medium, such as an optical storage medium or a solid-state medium supplied together with, or as part of, other hardware. The computer program may also be distributed in other forms, such as via the Internet or other wired or wireless telecommunication systems. For example, the computer program can be obtained and loaded into an apparatus, including obtaining the computer program through physical medium or distributed system, including, for example, from a server connected to the Internet.

[0180] The computer program may be accessible from a computer-readable medium providing program instructions for use by or in connection with a computer or any instruction execution system. The computer readable medium may include any apparatus that stores, communicates, propagates, or transports the computer program for use by or in connection with an instruction execution system, apparatus, or device. The computer-readable medium can be magnetic, optical, electronic, electromagnetic, infrared, or semiconductor system (or apparatus or device) or a propagation medium. The computer-readable medium may include a computer- readable non-transitory storage medium such as a semiconductor or solid-state memory, magnetic tape, a removable computer diskette, a random access memory (RAM), a read-only memory (ROM), a magnetic disk and an optical disk, and the like. The computer-readable non- transitory storage medium can include all types of computer readable medium, including magnetic storage medium, optical storage medium, flash medium, and solid state storage medium.

[0181] The techniques described above, can be implemented as computer software using computer-readable instructions and physically stored in one or more computer-readable media. For example, FIG. 8 shows a computer system (800) suitable for implementing certain embodiments of the disclosed subject matter.

[0182] The computer software can be coded using any suitable machine code or computer language, that may be subject to assembly, compilation, linking, or like mechanisms to create code comprising instructions that can be executed directly, or through interpretation, micro-code execution, and the like, by one or more computer central processing units (CPUs), Graphics Processing Units (GPUs), and the like.

[0183] The instructions can be executed on various types of computers or components thereof, including, for example, personal computers, tablet computers, servers, smartphones, gaming devices, internet of things devices, and the like.

[0184] The components shown in FIG. 8 for computer system (800) are exemplary in nature and are not intended to suggest any limitation as to the scope of use or functionality of the computer software implementing embodiments of the present disclosure. Neither should the configuration of components be interpreted as having any dependency or requirement relating to any one or combination of components illustrated in the exemplary embodiment of a computer system (800).

[0185] Computer system (800) may include certain human interface input devices. Such a human interface input device may be responsive to input by one or more human users through, for example, tactile input (such as: keystrokes, swipes, data glove movements), audio input (such as: voice, clapping), visual input (such as: gestures), olfactory input (not depicted). The human interface devices can also be used to capture certain media not necessarily directly related to conscious input by a human, such as audio (such as: speech, music, ambient sound), images (such as: scanned images, photographic images obtain from a still image camera), video (such as two-dimensional video, three-dimensional video including stereoscopic video).

[0186] Input human interface devices may include one or more of (only one of each depicted): keyboard (801), mouse (802), trackpad (803), touch screen (810), data-glove (not shown), joystick (805), microphone (806), scanner (807), and camera (808).

[0187] Computer system (800) may also include certain human interface output devices. Such human interface output devices may be stimulating the senses of one or more human users through, for example, tactile output, sound, light, and smell/taste. Such human interface output devices may include tactile output devices (for example tactile feedback by the touch-screen (810), data-glove (not shown), or joystick (805), but there can also be tactile feedback devices that do not serve as input devices), audio output devices (such as: speakers (809), headphones (not depicted)), visual output devices (such as screens (810) to include CRT screens, LCD screens, plasma screens, OLED screens, each with or without touch-screen input capability, each with or without tactile feedback capability — some of which may be capable to output two dimensional visual output or more than three dimensional output through means such as stereographic output; virtual-reality glasses (not depicted), holographic displays and smoke tanks (not depicted)), and printers (not depicted). These visual output devices (such as screens (810)) can be connected to a system bus (848) through a graphics adapter (850).

[0188] Computer system (800) can also include human accessible storage devices and their associated media such as optical media including CD/DVD ROM/RW (820) with CD/DVD or the like media (821), thumb-drive (822), removable hard drive or solid state drive (823), legacy magnetic media such as tape and floppy disc (not depicted), specialized ROM/ASIC/PLD based devices such as security dongles (not depicted), and the like.

[0189] Those skilled in the art should also understand that term “computer readable media” as used in connection with the presently disclosed subject matter does not encompass transmission media, carrier waves, or other transitory signals. [0190] Computer system (800) can also include a network interface (854) to one or more communication networks (855). The one or more communication networks (855) can for example be wireless, wireline, optical. The one or more communication networks (855) can further be local, wide-area, metropolitan, vehicular and industrial, real-time, delay -tolerant, and so on. Examples of the one or more communication networks (855) include local area networks such as Ethernet, wireless LANs, cellular networks to include GSM, 3G, 4G, 5G, LTE and the like, TV wireline or wireless wide area digital networks to include cable TV, satellite TV, and terrestrial broadcast TV, vehicular and industrial to include CANBus, and so forth. Certain networks commonly require external network interface adapters that attached to certain general purpose data ports or peripheral buses (849) (such as, for example USB ports of the computer system (800)); others are commonly integrated into the core of the computer system (800) by attachment to a system bus as described below (for example Ethernet interface into a PC computer system or cellular network interface into a smartphone computer system). Using any of these networks, computer system (800) can communicate with other entities. Such communication can be uni-directional, receive only (for example, broadcast TV), uni-directional send-only (for example CANbus to certain CANbus devices), or bi-directional, for example to other computer systems using local or wide area digital networks. Certain protocols and protocol stacks can be used on each of those networks and network interfaces as described above.

[0191] Aforementioned human interface devices, human-accessible storage devices, and network interfaces can be attached to a core (840) of the computer system (800).

[0192] The core (840) can include one or more Central Processing Units (CPU) (841), Graphics Processing Units (GPU) (842), specialized programmable processing units in the form of Field Programmable Gate Areas (FPGA) (843), hardware accelerators for certain tasks (844), graphics adapters (850), and so forth. These devices, along with Read-only memory (ROM) (845), Random-access memory (846), internal mass storage (847) such as internal non-user accessible hard drives, SSDs, and the like, may be connected through the system bus (848). In some computer systems, the system bus (848) can be accessible in the form of one or more physical plugs to enable extensions by additional CPUs, GPU, and the like. The peripheral devices can be attached either directly to the core’s system bus (848), or through a peripheral bus (849). In an example, the screen (810) can be connected to the graphics adapter (850). Architectures for a peripheral bus include PCI, USB, and the like. [0193] CPUs (841), GPUs (842), FPGAs (843), and accelerators (844) can execute certain instructions that, in combination, can make up the aforementioned computer code. That computer code can be stored in ROM (845) or RAM (846). Transitional data can also be stored in RAM (846), whereas permanent data can be stored for example, in the internal mass storage (847). Fast storage and retrieve to any of the memory devices can be enabled through the use of cache memory, that can be closely associated with one or more CPU (841), GPU (842), mass storage (847), ROM (845), RAM (846), and the like.

[0194] The computer readable media can have computer code thereon for performing various computer-implemented operations. The media and computer code can be those specially designed and constructed for the purposes of the present disclosure, or they can be of the kind well known and available to those having skill in the computer software arts.

[0195] As an example and not by way of limitation, the computer system having architecture (800) and specifically the core (840) can provide functionality as a result of processor(s) (including CPUs, GPUs, FPGA, accelerators, and the like) executing software embodied in one or more tangible, computer-readable media. Such computer-readable media can be media associated with user-accessible mass storage as introduced above, as well as certain storage of the core (840) that are of non-transitory nature, such as core-internal mass storage (847) or ROM (845). The software implementing various embodiments of the present disclosure can be stored in such devices and executed by core (840). A computer-readable medium can include one or more memory devices or chips, according to particular needs. The software can cause the core (840) and specifically the processors therein (including CPU, GPU, FPGA, and the like) to execute particular processes or particular parts of particular processes described herein, including defining data structures stored in RAM (846) and modifying such data structures according to the processes defined by the software. In addition or as an alternative, the computer system can provide functionality as a result of logic hardwired or otherwise embodied in a circuit (for example: accelerator (844)), which can operate in place of or together with software to execute particular processes or particular parts of particular processes described herein. Reference to software can encompass logic, and vice versa, where appropriate. Reference to a computer-readable media can encompass a circuit (such as an integrated circuit (IC)) storing software for execution, a circuit embodying logic for execution, or both, where appropriate. The present disclosure encompasses any suitable combination of hardware and software.

[0196] While this disclosure has described several exemplary embodiments, there are alterations, permutations, and various substitute equivalents, which fall within the scope of the disclosure. It will thus be appreciated that those skilled in the art will be able to devise numerous systems and methods which, although not explicitly shown or described herein, embody the principles of the disclosure and are thus within the spirit and scope thereof.

Claims

WHAT IS CLAIMED IS:

1. A method for a stylus to cooperate with one or more touch display devices, the method comprising: assigning, by the stylus, a first uplink code to a first touch display device of the one or more touch display devices; and in response to receiving, by the stylus and from touch driving circuitry of the first touch display device, a first uplink signal including the first uplink code, sending, from the stylus to the touch driving circuitry of the first touch display device, a first acknowledge (ACK) signal to inform the first touch display device to be ready for receiving a downlink signal from the stylus, and sending, from the stylus to the touch driving circuitry of the first touch display device, the downlink signal including at least position information or tilt information of the stylus.

2. The method of claim 1, further comprising: establishing, by the stylus, a first Bluetooth connection with the first touch display device, wherein the first uplink code is assigned by the stylus via the first Bluetooth connection to the first touch display device.

3. The method of claim 1, further comprising: establishing, by the stylus, a second Bluetooth connection with a second touch display device of the one or more touch display devices; assigning, by the stylus and via the second Bluetooth connection, a second uplink code to the second touch display device, the second uplink code being different from the first uplink code; and scanning, by the stylus, for the second uplink code.

4. The method of claim 1, wherein the first uplink signal includes a beacon for clock synchronization between the stylus and the touch driving circuitry of the first touch display device, and the method further comprises: performing, by the stylus, the clock synchronization based on the beacon included in the first uplink signal.

5. The method of claim 1, further comprising: after sending the downlink signal, determining whether a second uplink signal including the first uplink code is received by the stylus from the touch driving circuitry of the first touch display device; and in response to determining that the second uplink signal including the first uplink code is not received by the stylus, running a timer to count a timeout period, and stop sending the downlink signal based on the timeout period being greater than a timeout threshold.

6. The method of claim 1, further comprising: in response to not receiving the first uplink signal including the first uplink code, determining whether there is a third touch display device of the one or more touch display devices that was previously and is not currently Bluetooth connected to the stylus, and sending a Bluetooth connection request to the third touch display device based on a determination that there is the third touch display device that was previously and is not currently Bluetooth connected to the stylus.

7. The method of claim 6, further comprising: in response to receiving, by the stylus and from the third touch display device, a second ACK signal indicating that the Bluetooth connection request is received by the third touch display device and a third Bluetooth connection is established between the stylus and the third touch display device, updating, by the stylus, a list of connected devices to include the third touch display device, and assigning, by the stylus and via the third Bluetooth connection, a third uplink code to the third touch display device, the third uplink code being different from the first uplink code.

8. An apparatus, comprising: processing circuitry configured to assign a first uplink code to a first touch display device of one or more touch display devices, and in response to receiving, from touch driving circuitry of the first touch display device, a first uplink signal including the first uplink code, send, to the touch driving circuitry of the first touch display device, a first acknowledge (ACK) signal to inform the first touch display device to be ready for receiving a downlink signal from the apparatus, and send, to the touch driving circuitry of the first touch display device, the downlink signal including at least position information or tilt information of the apparatus.

9. The apparatus of claim 8, wherein the processing circuitry is further configured to: establish a first Bluetooth connection with the first touch display device, wherein the first uplink code is assigned via the first Bluetooth connection to the first touch display device.

10. The apparatus of claim 8, wherein the processing circuitry is further configured to: establish a second Bluetooth connection with a second touch display device of the one or more touch display devices, assign, via the second Bluetooth connection, a second uplink code to the second touch display device, the second uplink code being different from the first uplink code, and scan for the second uplink code.

11. The apparatus of claim 8, wherein the first uplink signal includes a beacon for clock synchronization between the apparatus and the touch driving circuitry of the first touch display device, and the processing circuitry is further configured to: perform the clock synchronization based on the beacon included in the first uplink signal.

12. The apparatus of claim 8, wherein the processing circuitry is further configured to: after sending the downlink signal, determine whether a second uplink signal including the first uplink code is received by the apparatus from the touch driving circuitry of the first touch display device, and in response to determining that the second uplink signal including the first uplink code is not received by the apparatus, run a timer to count a timeout period, and stop sending the downlink signal based on the timeout period being greater than a timeout threshold.

13. The apparatus of claim 8, wherein the processing circuitry is further configured to: in response to not receiving the first uplink signal including the first uplink code, determine whether there is a third touch display device of the one or more touch display devices that was previously and is not currently Bluetooth connected to the apparatus, and send a Bluetooth connection request to the third touch display device based on a determination that there is the third touch display device that was previously and is not currently Bluetooth connected to the apparatus.

14. The apparatus of claim 13, wherein the processing circuitry is further configured to: in response to receiving, from the third touch display device, a second ACK signal indicating that the Bluetooth connection request is received by the third touch display device and a third Bluetooth connection is established between the apparatus and the third touch display device, update a list of connected devices to include the third touch display device, and assign, via the third Bluetooth connection, a third uplink code to the third touch display device, the third uplink code being different from the first uplink code.

15. A non-transitory computer-readable medium storing instructions which, when executed by an apparatus, cause the apparatus to perform: assigning a first uplink code to a first touch display device of one or more touch display devices; and in response to receiving, from touch driving circuitry of the first touch display device, a first uplink signal including the first uplink code, sending, to the touch driving circuitry of the first touch display device, a first acknowledge (ACK) signal to inform the first touch display device to be ready for receiving a downlink signal from the apparatus, and sending, to the touch driving circuitry of the first touch display device, the downlink signal including at least position information or tilt information of the apparatus.

16. The non-transitory computer-readable medium of claim 15, wherein the stored instructions cause the apparatus to perform: establishing a first Bluetooth connection with the first touch display device, wherein the first uplink code is assigned by the apparatus via the first Bluetooth connection to the first touch display device.

17. The non-transitory computer-readable medium of claim 15, wherein the stored instructions cause the apparatus to perform: establishing a second Bluetooth connection with a second touch display device of the one or more touch display devices; assigning, via the second Bluetooth connection, a second uplink code to the second touch display device, the second uplink code being different from the first uplink code; and scanning for the second uplink code.

18. The non-transitory computer-readable medium of claim 15, wherein the first uplink signal includes a beacon for clock synchronization between the apparatus and the touch driving circuitry of the first touch display device, and the stored instructions cause the apparatus to perform: performing the clock synchronization based on the beacon included in the first uplink signal.

19. The non-transitory computer-readable medium of claim 15, wherein the stored instructions cause the apparatus to perform: after sending the downlink signal, determining whether a second uplink signal including the first uplink code is received by the apparatus from the touch driving circuitry of the first touch display device; and in response to determining that the second uplink signal including the first uplink code is not received by the apparatus, running a timer to count a timeout period, and stop sending the downlink signal based on the timeout period being greater than a timeout threshold.

20. The non-transitory computer-readable medium of claim 15, wherein the stored instructions cause the apparatus to perform: in response to not receiving the first uplink signal including the first uplink code, determining whether there is a third touch display device of the one or more touch display devices that was previously and is not currently Bluetooth connected to the apparatus, and sending a Bluetooth connection request to the third touch display device based on a determination that there is the third touch display device that was previously and is not currently Bluetooth connected to the apparatus.