Touch controller

Abstract

Even after entering uplink power-saving mode in response to a suspend command from the host computer, the system will be able to detect the pen before any pen touch occurs. [Solution] The touch controller is configured to determine the position of the pen and output a report including the determined position to the host computer. When the reception of the report from the touch controller is interrupted for a certain period of time, the touch controller receives a suspend command from the host computer and operates in an uplink power saving mode in which the power required to transmit the uplink signal is reduced by transmitting the uplink signal in a second period longer than the first period. When a predetermined trigger is detected while operating in the uplink power saving mode, the touch controller returns to a normal mode in which the uplink signal is transmitted in the first period.

Description

Technical Field

[0001] The present invention relates to a touch controller and a pen input system.

Background Art

[0002] A pen input system including a pen and a pen input device that receives input by the pen is known. The pen input device is, for example, a tablet-type computer or a digitizer, and generally includes a touch controller that detects the pen and a host computer. The host computer is a device that executes various software including an operating system, various applications, and drivers for various hardware. The driver executed by the host computer includes a driver for the touch controller.

[0003] Various types of pens are known as pens used in a pen input system. For example, in Patent Document 1, a pen (first stylus 110) configured to detect an uplink signal transmitted by a pen input device and transmit a pen signal when detecting the uplink signal corresponding to two-way communication between the pen and the pen input device, a pen (second stylus 120) configured to correspond only to one-way communication from the pen to the pen input device and continuously transmit a pen signal while the power is on, and a pen (dual-mode stylus 130) configured to correspond to both two-way communication and one-way communication, alternately repeating detection of an uplink signal and transmission of a pen signal, shifting to two-way communication when detecting an uplink signal, and shifting to one-way communication and repeatedly transmitting a pen signal when detecting a pen touch without detecting an uplink signal are described.

[0004] Furthermore, regarding the Universal Serial Bus (USB) standard, one of the standards for connecting computers and peripheral devices, a function called selective suspend is known (see Non-Patent Literature 1). This function reduces the power consumption of peripheral devices connected to a host computer via USB, and is activated when the driver running on the host computer stops transmitting SOF (Start of Frame) signals. When selective suspend is activated, the peripheral device operates with only the minimum power necessary to detect a wake-up event and generate a resume signal when the event occurs. A wake-up event, for example, in the case of a mouse, is a slight vibration, and the peripheral device that detects the wake-up event returns from sleep to normal. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] International Publication No. 2016 / 129194 [Non-patent literature]

[0006] [Non-Patent Document 1] "About USB Selective Suspend," [online], July 7, 2011, Microsoft Japan Co., Ltd., Windows & Devices Development Division, [Retrieved September 7, 2019], Internet<URL:https: / / blogs.msdn.microsoft.com / jpwin / 2011 / 07 / 07 / usb-2 / > [Overview of the project] [Problems that the invention aims to solve]

[0007] However, the conventional selective suspend described above has not been applied to touch controllers. This is because pens that operate like the dual-mode stylus described in Patent Document 1 are rare, and in the detection of a typical pen that supports bidirectional communication and transmits a signal after detecting an uplink signal, it is not possible to stop the transmission of the uplink signal by the touch controller. However, if this is done, the touch controller will constantly consume a large amount of power, so improvement was needed from the perspective of reducing power consumption.

[0008] Therefore, one of the objectives of the present invention is to achieve low power consumption in touch controllers.

[0009] Furthermore, if the uplink signal transmission is stopped in a touch controller while it is in sleep mode, a pen that supports bidirectional communication will not be able to obtain an opportunity to transmit a pen signal and will not be able to start communication with the touch controller.

[0010] Therefore, one of the objectives of the present invention is to enable communication between a bidirectional pen and a touch controller even if the transmission of an uplink signal is stopped in a touch controller that is in a sleep state. [Means for solving the problem]

[0011] The touch controller according to the present invention operates in an uplink power-saving mode that reduces the power required to transmit uplink signals in response to a suspend command from a host computer, and returns to normal mode in response to the detection of a predetermined trigger while operating in the uplink power-saving mode.

[0012] The pen input system according to the present invention includes a pen configured to start transmitting a pen signal in response to detection of a pen touch, and a touch controller that operates in an uplink power-saving mode without transmitting an uplink signal in response to a suspend command from a host computer, and returns to normal mode in response to detection of the pen signal while operating in the uplink power-saving mode. [Effects of the Invention]

[0013] According to the touch controller of the present invention, the touch controller can be returned to normal mode by a predetermined trigger regardless of the uplink signal, thereby achieving low power consumption for the touch controller.

[0014] Furthermore, according to the pen input system of the present invention, since the pen starts transmitting a pen signal in response to the detection of a pen touch, even if the transmission of the uplink signal is stopped in uplink power saving mode, it becomes possible to return the touch controller to normal mode by using the pen signal as a trigger. [Brief explanation of the drawing]

[0015] [Figure 1] This figure shows the configuration of a pen input system 10 according to the first embodiment of the present invention. [Figure 2] This diagram shows the sequence of signals transmitted and received between the touch controller 3 and the pen 5. [Figure 3] This figure shows the processing of the touch controller 3 according to the first example. [Figure 4] This figure shows the processing of the touch controller 3 according to the second example. [Figure 5] This figure shows the processing of the touch controller 3 according to the third example. [Figure 6] This figure shows the processing of the touch controller 3 according to the fourth example. [Figure 7] This figure shows the processing of the touch controller 3 according to the fifth example.

Best Mode for Carrying Out the Invention

[0016] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0017] FIG. 1 is a diagram showing the configuration of a pen input system 10 according to a first embodiment of the present invention. As shown in the figure, the pen input system 10 includes a pen input device 1 and a pen 5.

[0018] The pen input device 1 is a device that realizes input by the pen 5 and is configured to have a touch surface for pen input. In a specific example, the pen input device 1 is a tablet-type computer or a digitizer. In the former case, the touch surface is constituted by the panel surface of the display.

[0019] As shown in FIG. 1, the pen input device 1 includes a sensor electrode group 2, a touch controller 3, and a host computer 4. The sensor electrode group 2 is a plurality of sensor electrodes arranged directly below the touch surface. The plurality of sensor electrodes constituting the sensor electrode group 2 each include a plurality of X electrodes 2x extending in the illustrated y direction and arranged at equal intervals in the x direction (a direction orthogonal to the y direction), and a plurality of Y electrodes 2y extending in the illustrated x direction and arranged at equal intervals in the y direction.

[0020] The touch controller 3 is an integrated circuit connected to the sensor electrode group 2 and is configured to be able to derive the position of the pen 5 within the touch surface, and is also configured to be able to derive the position of the finger F within the touch surface. In a typical example, the touch controller 3 detects the pen 5 by an active electrostatic method and detects the finger F by a capacitance method. Although details will be described later, the derivation of the position of the pen 5 and the derivation of the position of the finger F are executed alternately. Each time the touch controller 3 derives the position of the pen 5 or the finger F, it is configured to transmit a report indicating the derived position to the host computer 4. The report includes, in addition to the derived position, data (such as pen pressure value, pen ID, etc.) transmitted by the pen 5 by a data signal described later.

[0021] Here, the touch controller 3 and the pen 5 are configured to communicate bidirectionally, for example, using an active electrostatic method. Specifically, the touch controller 3 is configured to periodically transmit an uplink signal US using the sensor electrode group 2 as a transmitting antenna. When the pen 5 receives this uplink signal US, it is configured to transmit a pen signal PS from an electrode (pen tip electrode) provided at the tip of the pen accordingly. The touch controller 3 receives this pen signal PS via electrostatic coupling between the pen tip electrode of the pen 5 and the sensor electrode group 2, and derives the position of the pen 5 based on the result.

[0022] The pen signal PS is a signal that includes a burst signal, which is an unmodulated carrier signal, and a data signal that is modulated by various data. Of these, the burst signal is used by the touch controller 3 to determine the position of the pen 5. That is, the touch controller 3 detects the received intensity of the burst signal for each of the multiple sensor electrodes that make up the sensor electrode group 2. Then, based on the position of each sensor electrode and the received intensity at each, the touch controller 3 determines the position of the pen 5.

[0023] On the other hand, the data signal is used to transmit various types of data from the pen 5 to the touch controller 3. The data transmitted by the data signal includes a pen ID, which is uniquely assigned to each pen 5, and a pressure value indicating the pressure applied to the tip of the pen 5. The pen ID is pre-stored in the memory of the pen 5. The pressure value is detected by a pressure sensor built into the pen 5. The specific type of data that the pen 5 transmits by the data signal is instructed by the touch controller 3 via a command in the uplink signal US.

[0024] Figure 2 shows the sequence of signals transmitted and received between the touch controller 3 and the pen 5. In this figure and the figures shown later, signal B represents the burst signal that constitutes the pen signal PS, signal D represents the data signal that constitutes the pen signal PS, reception period Ra represents the reception period of burst signal B, reception period Rb represents the reception period of data signal D, reception period Rp represents the reception period of uplink signal US, and period T represents the detection period of the touch operation by finger F.

[0025] As can be seen from Figure 2, the touch controller 3 operating in normal mode is configured to repeatedly transmit the uplink signal US at a fixed period T1 (first period). Within this first period T1, it is also configured to receive the burst signal B transmitted by the pen 5 immediately after transmitting the uplink signal US, and to detect the touch operation by the finger F. In this case, the transmission voltage of the uplink signal US is the first voltage (for example, 9V).

[0026] Pen 5 waits in a state where it can receive the uplink signal US until the uplink signal US is received. When Pen 5 approaches the touch surface and becomes able to receive the uplink signal US, it receives the first uplink signal US transmitted thereafter. In the example in Figure 2, at time t0, Pen 5 has entered the receivable range of the uplink signal US. Hereafter, Pen 5 entering the receivable range of the uplink signal US will be referred to as "pen down".

[0027] After pen 5 receives the uplink signal US after pen-down, it transmits burst signal B in response to the uplink signal US. Touch controller 3 receives this burst signal B and derives the position of pen 5 as described above. Pen 5 also transmits data signal D following burst signal B. Touch controller 3 also receives this data signal D and obtains the data transmitted by pen 5 by demodulating it. Subsequently, although not shown in Figure 2, touch controller 3 generates a report containing the derived position and acquired data and outputs it to host computer 4.

[0028] Figure 2 also shows the time t1 when the tip of pen 5 touches the touch surface. Hereafter, the act of the tip of pen 5 touching the touch surface will be referred to as "pen touch". After the pen touch, the pressure value detected by pen 5 changes to a value greater than 0, but the configuration of the transmitted and received signals is the same as before the pen touch.

[0029] Returning to Figure 1, the host computer 4 is a device that includes a processor, memory, and various input / output devices such as a display and communication devices. The touch controller 3 constitutes one of the various input / output devices provided in the host computer 4. The host computer 4 is configured to run various software, including an operating system, various applications, and drivers for various hardware. The drivers include the driver 4a for the touch controller 3. The various applications include drawing applications that generate stroke data based on pen input and perform drawing.

[0030] To specifically explain the pen input-related functions of the drawing application, when the drawing application receives a report from the touch controller 3, it first acquires the position data contained within it. Then, based on the multiple position data acquired sequentially, it generates stroke data consisting of a series of control points. Furthermore, if the report contains a pen ID, the drawing application performs processing based on that pen ID. This processing, for example, involves setting the drawing color associated with that pen ID in the application to the stroke data. In addition, if the report contains a pressure value, the drawing application performs processing to set the line width or transparency of the stroke data according to that pressure value.

[0031] Driver 4a receives reports from the touch controller 3 and passes them to various applications. In addition, if the reception of reports is interrupted for a certain period of time, driver 4a sends a suspend command to the touch controller 3. This suspend command may be physically executed by sending a predetermined signal from driver 4a to the touch controller 3, or by stopping the transmission of a signal normally sent from driver 4a to the touch controller 3 (for example, the SOF mentioned above). Upon receiving the suspend command, the touch controller 3 enters an uplink power-saving mode that reduces the power required to transmit the uplink signal. Subsequently, the touch controller 3 continues to perform a predetermined trigger detection operation, and returns to normal mode depending on whether a predetermined trigger has been detected as a result.

[0032] The following explains in detail, with five examples, the processes that the touch controller 3 performs when it receives a suspend command.

[0033] Figure 3 shows the processing of the touch controller 3 according to the first example. In this example, the touch controller 3 reduces the power required to transmit the uplink signal by lowering the transmission voltage of the uplink signal US. Furthermore, as a predetermined trigger, the pen signal PS transmitted by the pen 5 in response to the uplink signal US transmitted with the transmission voltage reduced is used. A detailed explanation follows below.

[0034] After receiving a suspend command at time t2 and entering uplink power saving mode, the touch controller 3 transmits uplink signal US' instead of uplink signal US. Uplink signal US' is different from uplink signal US in that its transmission voltage is a second voltage (e.g., 3.3V) that is lower than the first voltage (e.g., 9V) mentioned above. In other respects, the operation of the touch controller 3 is the same as in normal mode. In the following, "pen down state" refers to the state in which pen 5 is within the receivable range of uplink signal US transmitted in normal mode.

[0035] Due to the low transmission voltage, the receivable range of the uplink signal US' is narrower than that of the uplink signal US. As a result, pen 5 needs to get even closer to the touch surface than it does to receive the uplink signal US' in order to receive the uplink signal US'. In the example in Figure 2, even though pen 5 is in the pen-down state at time t3, pen 5 has not received the uplink signal US' transmitted immediately afterward. This is because pen 5 has entered the receivable range of uplink signal US, but has not yet entered the receivable range of uplink signal US'. However, normally, when a user uses pen 5 to input, pen 5 moves closer and closer to the touch surface. As a result, pen 5 is able to receive the next uplink signal US'. In response to receiving the pen signal PS transmitted by pen 5, which has thus received the uplink signal US', touch controller 3 returns to normal mode at time t4.

[0036] Figure 4 shows the processing of the touch controller 3 according to the second example. In this example, the touch controller 3 reduces the power required to transmit the uplink signal by extending the transmission period of the uplink signal US. Also, as in the first example, the pen signal PS transmitted by the pen 5 in response to the uplink signal US is used as the predetermined trigger. A detailed explanation follows below.

[0037] After receiving a suspend command at time t5 and entering uplink power-saving mode, the touch controller 3 changes the transmission period of the uplink signal US from the first period T1 described above to a longer second period T2 (>T1). Accordingly, the reception period of the burst signal B and the execution period of the touch detection operation are also changed from the first period T1 to the second period T2. In other respects, the operation of the touch controller 3 is the same as in normal mode.

[0038] Because the transmission cycle of the uplink signal US is long, the detection timing of pen 5 is delayed in uplink power saving mode compared to normal mode. However, it is not impossible to detect it indefinitely; eventually, pen 5 can be detected. In the example in Figure 4, at time t7, after pen 5 has entered the pen-down state at time t6, the touch controller 3 is able to detect the pen signal PS transmitted by pen 5. Here, time t7 is at most the second cycle T2 later than time t6. In response to detecting the pen signal PS in this way, the touch controller 3 returns to normal mode.

[0039] Figure 5 shows the processing of the touch controller 3 according to the third example. In this example, the touch controller 3 reduces the power required to transmit the uplink signal by reducing the frequency of transmission of the uplink signal US. Also, as in the first and second examples, the pen signal PS transmitted by the pen 5 in response to the uplink signal US is used as the predetermined trigger. A detailed explanation follows below.

[0040] After receiving a suspend command at time t8 and entering uplink power-saving mode, the touch controller 3 changes the transmission frequency of the uplink signal US from a first frequency (once every first period T1) to a second frequency (for example, once every n times the first period T1, where n is an integer greater than or equal to 2). Figure 5 shows an example where n=2. Accordingly, the execution frequency of the burst signal B reception operation is also changed from the first frequency to the second frequency. In other respects, the operation of the touch controller 3 is the same as in normal mode.

[0041] Because the uplink signal US is transmitted less frequently, the detection timing of pen 5 is delayed in uplink power saving mode compared to normal mode. However, it is not impossible to detect it indefinitely; eventually, pen 5 can be detected. In the example in Figure 4, at time t10, after pen 5 has entered the pen-down state at time t9, the touch controller 3 is able to detect the pen signal PS transmitted by pen 5. Here, time t10 is at most n × T1 later than time t9. In response to detecting the pen signal PS in this way, the touch controller 3 returns to normal mode.

[0042] Figure 6 shows the processing of the touch controller 3 according to the fourth example. In this example, the touch controller 3 reduces the power required to transmit the uplink signal US by stopping its transmission. Furthermore, finger touch detection is used as the predetermined trigger. This will be explained in detail below.

[0043] After receiving a suspend command at time t11 and entering uplink power-saving mode, the touch controller 3 stops transmitting the uplink signal US. Consequently, the reception of burst signal B is also stopped. In other respects, the operation of the touch controller 3 is the same as in normal mode.

[0044] In this example, since the touch controller 3 stops transmitting the uplink signal US, the pen 5 cannot transmit the pen signal PS. In the example in Figure 6, a pen down occurs at time t12, but since the uplink signal US is not transmitted, the pen 5 does not transmit the pen signal PS. Therefore, the reception of the pen signal PS cannot be used as a trigger to return the touch controller 3 to normal mode.

[0045] Therefore, in this example, we utilize the touch detection operation that the touch controller 3 periodically performs. Specifically, when a touch operation by finger F is detected at time t13, the touch controller 3 is returned to normal mode. As a result, the transmission of the uplink signal US resumes, and the touch controller 3 becomes able to detect the pen 5 as usual.

[0046] Figure 7 shows the processing of the touch controller 3 according to the fifth example. In this example, the pen 5 is configured to start transmitting a pen signal PS in response to the detection of a pen touch. The pen 5 only needs to detect a pen touch when it detects that pressure has been applied to the pen tip (i.e., that the pen pressure value has become greater than 0) by the pressure sensor described above. The touch controller 3 is configured to reduce the power required to transmit the uplink signal by stopping the transmission of the uplink signal US, while intermittently receiving the pen signal PS (burst signal B) while in uplink power saving mode. The predetermined trigger in this example is the pen signal PS received by this receiving operation. This will be explained in detail below.

[0047] Touch controller 3 receives a suspend command at time t14, enters uplink power saving mode, and then stops transmitting the uplink signal US. It also receives burst signal B when not performing touch detection. In other respects, the operation of touch controller 3 is the same as in normal mode.

[0048] When pen 5 detects a pen touch at time t15, it transmits burst signal B for a certain period of time, and then returns to waiting to receive uplink signal US. Touch controller 3, upon detecting the transmitted burst signal B, returns to normal mode at time t16. After that, transmission of uplink signal US resumes, and touch controller 3 becomes able to detect pen 5 as usual.

[0049] As described above, according to this embodiment, regardless of the uplink signal US (i.e., whether or not the uplink signal US is transmitted while operating in uplink power saving mode), a predetermined trigger can return the touch controller 3, which is operating in uplink power saving mode, to normal mode. Therefore, low power consumption of the touch controller 3 is achieved.

[0050] Furthermore, according to the fifth example in particular, since the pen 5 starts transmitting the pen signal PS in response to the detection of a pen touch, even if the transmission of the uplink signal US is stopped in uplink power saving mode, the pen signal PS can be used as a trigger to return the touch controller 3 to normal mode.

[0051] Although preferred embodiments of the present invention have been described above, the present invention is not limited in any way to these embodiments, and it goes without saying that the present invention can be implemented in various forms without departing from its essence.

[0052] For example, the first to fifth examples described above may be used individually or in any combination. For instance, a touch controller 3 that has entered uplink power saving mode may reduce the transmission voltage of the uplink signal US, extend the transmission period, and reduce the transmission frequency. Also, when reducing the power required for transmitting the uplink signal by stopping the transmission of the uplink signal US, both detection of a finger touch and detection of a pen signal PS by the pen 5 in response to the detection of a pen touch may be used as predetermined triggers for returning to normal mode. Furthermore, even if the transmission of the uplink signal US is not stopped, detection of a finger touch may be used as a predetermined trigger for returning to normal mode. [Explanation of Symbols]

[0053] 1. Pen input device 2 Sensor electrode group 2x,2y electrode 4. Host computer 4a Touch Controller 3 Driver 5 pens 10 Pen Input Systems B Burst Signal D Data signal F finger PS Pen Signal Reception period of Ra burst signal B Rb Reception period of data signal D Rp Uplink signal US reception period T-touch motion detection period US Uplink Signal

Claims

1. A touch controller configured to determine the position of a pen and output a report including the determined position to a host computer, If the reception of the report from the touch controller is interrupted for a certain period of time, the device operates in an uplink power-saving mode that reduces the power required to transmit the uplink signal by transmitting the uplink signal at a second cycle longer than the first cycle, in response to receiving a suspend command from the host computer. In response to detecting a predetermined trigger while operating in the uplink power-saving mode, the system returns to normal mode, which transmits the uplink signal at a first cycle. Touch controller.

2. A touch controller configured to determine the position of a pen and output a report including the determined position to a host computer, If the reception of the report from the touch controller is interrupted for a certain period of time, the device operates in an uplink power-saving mode in which it reduces the power required to transmit the uplink signal by transmitting the uplink signal at a second frequency less than the first frequency, in response to receiving a suspend command from the host computer. In response to detecting a predetermined trigger while operating in the uplink power-saving mode, the system returns to normal mode, which transmits the uplink signal at a first frequency. Touch controller.

3. The predetermined trigger is the reception of a pen signal transmitted by the pen. The touch controller according to claim 1 or 2.

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