JP6817236B2 - Sensor controller, system, and method - Google Patents

Description

The present invention relates to a stylus and a sensor controller, and more particularly to a stylus that transmits a downlink signal during hovering and a sensor controller that receives the downlink signal.

A stylus configured to be capable of transmitting a signal for position detection (position signal) and a signal (data signal) including various data such as a unique ID and pen pressure to a sensor controller is known. Hereinafter, the signals transmitted by the stylus to the sensor controller are collectively referred to as “downlink signals”. Patent Documents 1 to 3 disclose an example of a stylus that transmits a downlink signal.

In addition, when the user tries to input characters or pictures using the stylus, the stylus gradually approaches the touch surface of the electronic device including the sensor controller, and finally the core body comes into contact with the touch surface. Become. Characters and pictures can be input by the stylus when the core of the stylus is in contact with the touch surface. Hereinafter, the state in which the stylus core is in contact with the touch surface is referred to as a “contact” state, and the state in which the stylus core is not in contact with the touch surface is referred to as a “hover” state.

Patent Document 2 discloses a stylus that reduces the transmission intensity of the position signal in the contact state as compared with that in the hover state (Patent Document 2, 4th step, 57th line to 5th step, 3rd step). Line).

Patent Document 3 discloses a stylus that intermittently transmits only a position signal and some additional signals in a hover state, and further transmits a signal indicating pen pressure at that interval in a contact state. (Patent Document 2, 13th column, 33rd line to 14th column, 46th line, FIGS. 9A to 9C).

International Publication No. 2015/11159 U.S. Pat. No. 8,773,405 U.S. Pat. No. 8,536,471

By the way, when the S / N ratio of the downlink signal received by the sensor in the touch surface is compared between when the stylus is in the hover state and when it is in the contact state, it is smaller when the stylus is in the hover state. This is because the distance between the sensor and the stylus is large in the hover state, and the attenuation of the downlink signal is large. As a result, in the conventional technique, when the stylus is in the hover state, the sensor controller may fail to receive the downlink signal, and therefore improvement has been desired.

In this regard, according to the technique described in Patent Document 2, it is considered that the possibility of failure to receive the downlink signal in the hover state can be reduced. This is because the reception strength of the downlink signal in the hover state is higher than that in the contact state. However, according to this technique, another problem arises that a special transmitter corresponding to the variable transmission strength is required on the stylus side.

Therefore, one of the objects of the present invention is to provide a stylus and a sensor controller that can reduce the possibility of failure to receive the downlink signal in the hover state even if the downlink signal is transmitted with the same transmission strength as in the contact state. There is.

The stylus according to one aspect of the present invention controls a core body, electrodes provided near the core body, a transmission unit that transmits a signal including a first digital value using the electrodes, and the transmission unit. The control unit is provided with a control unit for determining whether the core body is in contact with the operation surface or is not in contact with the operation surface, and the result of the determination is the contact state. In this case, the first digital value is transmitted to the transmitting unit at the first bit rate, and when the result of the determination is the hover state, the first digital value is smaller than the first bit rate. It is a stylus that causes the transmitter to transmit at a bit rate of 2.

The stylus according to the other aspect of the present invention includes a core body, electrodes provided near the core body, a transmission unit that transmits a signal using the electrodes, and a control unit that controls the transmission unit. The control unit controls the transmission unit so as to transmit signals in units of super frames including a predetermined number of frames, and the control unit assigns a frame number indicating the order of the frames in the super frame. A stylus that controls the transmission unit to transmit by each of a predetermined number of frames.

The stylus according to still another aspect of the present invention includes a core body, an electrode provided near the core body, a transmission unit that transmits a signal including a first digital value using the electrode body, and the core body. It is determined whether the body is in contact with the operation surface or in the hover state without contact, and when the result of the determination is in the contact state, the first digital value is transmitted as the first signal. When the result of the determination is the hover state, the first digital value is transmitted to the transmission unit by a second signal transmission method having a smaller decoding error rate than the first signal transmission method. It is a stylus including a control unit.

The sensor controller according to the present invention acquires the stylus state information from the signal received from the stylus by the first demodulation method, and when the state information indicates that the stylus is in the hover state, it is included after the state information. When the first digital value is acquired by the first demodulation method and the state information indicates that the stylus is in a contact state, the first digital value included after the state information is the first digital value. This is a sensor controller acquired by a second demodulation method having a higher bit error rate than the demodulation method.

According to the present invention, the noise immunity in the hover state is improved, so that the reduction of the undetected rate of the downlink signal, the reduction of the bit error detection rate at the time of demodulation or decoding of the downlink signal, and the error correction are taken into consideration. The effect such as reduction of the decoding error rate can be obtained. Therefore, even if the downlink signal is transmitted with the same transmission strength as in the contact state, it is possible to reduce the possibility of failure in receiving the downlink signal in the hover state.

Further, according to the present invention, since each frame has a frame number, when the stylus divides one information into a plurality of frames and transmits the information, the sensor controller on the receiving side receives the divided information in order. Even if it is not received as expected, it is possible to restore the information based on the frame number.

It is a figure which shows the structure of the electronic device 3 by embodiment of this invention, (a) shows the operation of the electronic device 3 when the touch by a finger F is detected, and (b) is the case where the stylus 2 is detected. The operation of the electronic device 3 is shown. It is a figure which shows the structure of the electronic device 3 by embodiment of this invention. It is a figure which shows the structure of the long burst signal, the burst signal, and the data signal transmitted by the stylus 2 by embodiment of this invention. It is a figure which shows the sequence of the signal transmission and reception between the stylus 2 and the sensor controller 31 when the stylus 2 is above the uplink detection height AH, and (a) shows the time when the pen start signal is transmitted by the sensor controller 31. (B) shows each case where the sensor controller 31 requests the transmission of the long burst signal. FIG. 5 is a diagram showing a sequence of signal transmission / reception between the stylus 2 and the sensor controller 31 when the stylus 2 is inside the sensing range SR and the sensor controller 31 has not yet specified the position of the stylus 2. ) Is the case where the sensor controller 31 transmits the pen activation signal, (b) is the case where the sensor controller 31 receives the long burst signal transmitted by the stylus 2, and (c) is the case where the stylus 2 receives the long burst signal transmitted by the stylus 2. The case where the sensor controller 31 receives the transmitted long burst signal by using the linear electrode 30X is shown. It is a figure which shows the sequence of signal transmission and reception between a stylus 2 and a sensor controller 31 after a stylus 2 is inside a sensing range SR, and a sensor controller 31 has specified the position of a stylus 2, and is a stylus in a hover state. It shows the time of transmission of the burst signal and the data signal (the data to be transmitted is not a unique ID) according to 2. It is a figure explaining the operation of the sensor controller 31 by embodiment of this invention, (a) shows the first half of a full range scan, (b) shows the latter half of a full range scan, and (c) shows a sector scan. ing. It is a figure which shows the structure of the stylus 2 by embodiment of this invention. It is a processing flow diagram which shows the whole processing performed in the hover of the stylus 2 by the sensor controller 31 by embodiment of this invention. It is a figure which shows the format of the downlink signal transmitted by the stylus 2 of the Embodiment of this invention. It is a processing flow diagram which shows the reception process of the uplink signal and the transmission process of the downlink signal by the stylus 2 by the embodiment of this invention. It is a processing flow diagram which shows the transmission process of the uplink signal and the reception process of the downlink signal by the sensor controller 31 according to the embodiment of the present invention. It is a processing flow diagram which shows the transmission process of the uplink signal and the reception process of the downlink signal by the sensor controller 31 according to the embodiment of the present invention. It is a figure which shows 1st example of the data (A)-(C) and data (D) (E) transmission method by the stylus 2 by embodiment of this invention. It is a figure which shows the 2nd example of the data (A)-(C) and data (D) (E) transmission method by the stylus 2 by embodiment of this invention. It is a figure which shows the 3rd example of the data (A)-(C) and data (D) (E) transmission method by the stylus 2 by embodiment of this invention. It is a figure which shows the 4th example of the data (A)-(C) and data (D) (E) transmission method by the stylus 2 by embodiment of this invention. It is a figure which shows the 5th example of the data (A)-(C) and data (D) (E) transmission method by the stylus 2 by embodiment of this invention. It is a figure which shows the sixth example of the data (A)-(C) and data (D) (E) transmission method by the stylus 2 by embodiment of this invention. It is a figure which shows the structure of the stylus 2 by the 1st modification of the Embodiment of this invention. It is a processing flow diagram which shows the reception process of the uplink signal and the transmission process of the downlink signal by the stylus 2 by the 2nd modification of the Embodiment of this invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following, the outline of the configuration and operation of the stylus 2 and the sensor controller 31 according to the present embodiment will be described first with reference to FIGS. 1 to 8, and then the features of the present invention will be described with reference to FIGS. 9 to 19. The operation of the stylus 2 and the sensor controller 31 directly related to the above will be described.

FIG. 1 is a diagram showing a configuration of an electronic device 3 according to the present embodiment. The electronic device 3 is a computer having a touch surface (operation surface) such as a tablet terminal, and is configured to include a sensor 30 and a sensor controller 31 as shown in the figure.

The sensor 30 is a matrix electrode including M linear electrodes 30X (first electrode) and N (N <M) linear electrodes 30Y (second electrode) arranged inside the touch surface. Consists of. In a specific example, M = 72 and N = 46. The M linear electrodes 30X are arranged so as to extend at equal intervals in the first direction parallel to the touch surface. Further, the N linear electrodes 30Y are arranged so as to extend at equal intervals in the second direction parallel to the touch surface and orthogonal to the first direction. Each linear electrode 30X and each linear electrode 30Y are individually connected to the sensor controller 31.

The sensor 30 is arranged together with a display panel (not shown) such as a liquid crystal. The specific method of arranging the sensor 30 on the display panel is arbitrary. For example, the linear electrodes 30X and 30Y are out-cell type and the linear electrodes 30X and 30Y are arranged outside the display panel such as a liquid crystal display panel. Examples include an on-cell type that is placed on the internal color filter glass and base glass, and an in-cell type in which the driving electrode (specifically, a common electrode or pixel electrode) of the display panel serves as one of the linear electrodes 30X and 30Y. Be done.

The sensor controller 31 uses the sensor 30 to detect a touch by the finger F (including deriving the position coordinates of the finger F in the touch surface) and detect the stylus 2 (position coordinates of the stylus 2 in the touch surface). It is a control unit that performs time division (including derivation).

FIG. 1A shows the operation of the electronic device 3 when the touch by the finger F is detected. As shown in the figure, the sensor controller 31 when detecting the touch by the finger F sequentially supplies a predetermined signal (hereinafter, referred to as “finger detection signal”) to each of the plurality of linear electrodes 30Y. At the same time, by sequentially scanning the potentials of each of the plurality of linear electrodes 30X, the finger detection signal that has arrived at each linear electrode 30X through the intersection with the linear electrodes 30Y is detected. The amplitude of the finger detection signal detected in this way is smaller when the finger F is close to the intersection where the finger detection signal has passed than when the finger F is not close to the intersection. This is because a part of the current flowing on the linear electrodes 30X and 30Y flows out toward the human body through the capacitive coupling generated between the finger F and the linear electrodes 30X and 30Y. The sensor controller 31 detects the touch by the finger F by detecting such a change in amplitude.

FIG. 1B shows the basic operation of the electronic device 3 when detecting the stylus 2. As shown in the figure, the sensor controller 31 when detecting the stylus 2 uses, as a basic operation, each of the plurality of linear electrodes 30X and the plurality of linear electrodes 30Y as receiving electrodes in sequence, and the stylus The detection operation of the signal transmitted by 2 (hereinafter, referred to as “downlink signal”) is performed. Then, the stylus 2 is detected based on the detection result. In the actual operation, the stylus 2 may be detected by using only a part of the linear electrodes 30X and 30Y, which will be described later.

In order for the sensor controller 31 to detect the stylus 2, the stylus 2 needs to be close to the touch surface of the electronic device 3 to such an extent that the sensor controller 31 can receive the downlink signal. The illustrated sensing range SR schematically shows the range in which the sensor controller 31 can receive the downlink signal. When the stylus 2 enters the sensing range SR, the sensor controller 31 receives a downlink signal, whereby the stylus 2 can be detected. The movement of the stylus 2 to move from the outside to the inside of the sensing range SR is hereinafter referred to as "pen down". Pendown is usually performed by a user operation of bringing the stylus 2 closer to the touch surface of the electronic device 3. The above-mentioned hover state is, in detail, a state in which the stylus 2 has entered the sensing range SR by pen-down, but has not yet come into contact with the touch surface.

Further, the stylus 2 may be able to receive a signal (hereinafter, referred to as “uplink signal”) transmitted by the sensor controller 31 toward the stylus 2 even when it is outside the sensing range SR. This is because for some uplink signals (such as a pen activation signal described later and a command signal indicating a transmission instruction of a long burst signal), the entire surface of the touch surface (one or both of the all-linear electrode 30X and the all-linear electrode 30Y). This is because it is transmitted using. The illustrated uplink detection height AH indicates the limit of the height (distance from the touch surface) at which the stylus 2 can receive these uplink signals. The uplink detection height AH is a position higher than the upper limit of the sensing range SR (a position far from the touch surface).

FIG. 2 is a diagram showing a configuration of an electronic device 3 according to the present embodiment. The plurality of linear electrodes 30X and the plurality of linear electrodes 30Y constituting the sensor 30 are configured to be capacitively coupled to the stylus 2 and the finger F. When the finger F approaches the sensor 30, a part of the current flowing from the sensor controller 31 to the linear electrode 30Y is absorbed by the finger F through this capacitive coupling. As a result, the amplitude of the finger detection signal detected by the linear electrode 30X becomes smaller as described above, so that the sensor controller 31 can detect the touch by the finger F. Further, the sensor 30 is configured to be able to transmit and receive signals in both directions to and from the stylus 2 via the capacitive coupling.

As shown in FIG. 2, the sensor controller 31 includes a transmission unit 60, a selection unit 40, a reception unit 50, a logic unit 70, and an MCU 80.

The transmission unit 60 is a circuit that generates a finger detection signal at the timing of detecting the touch by the finger F and generates an uplink signal at the timing of detecting the stylus 2. The uplink signal includes a pen activation signal for notifying the stylus 2 of the existence of the sensor controller 31 and a command signal for indicating an instruction (command) to the stylus 2.

Only the functional block related to the generation of the uplink signal is shown in detail in the transmission unit 60 of FIG. This functional block includes a pattern supply unit 61, a switch 62, a diffusion processing unit 63, a code sequence holding unit 64, and a transmission guard unit 65. Of these, the pattern supply unit 61 will be described as being included in the transmission unit 60 in the present embodiment, but may be included in the MCU 80.

The pen activation signal is composed of the repetition of the predetermined detection pattern c1 and the predetermined delimiter pattern STP arranged at the end.

The detection pattern c1 is a pattern of symbol values used by the stylus 2 to detect the presence of the sensor controller 31, and is known to the stylus 2 in advance (before the stylus 2 detects the sensor controller 31). There is. A symbol is a unit of information used for modulation in transmission processing (a unit of information expressed by a transmission signal), and is a unit of information obtained by demodulating one symbol which is a reception signal in reception processing. The value of the symbol is a value that is converted into a bit string (hereinafter, referred to as "bit string compatible value") and a value that is not converted into a bit string by the stylus 2 that receives the symbol (hereinafter, referred to as "bit string non-compatible value"). Can include. In a specific example, the detection pattern c1 is composed of a pattern "PM" composed of a combination of two types of bit string non-corresponding values "P" and "M".

The delimiter pattern STP is a symbol value pattern for notifying the stylus 2 of the end of the repetition period of the detection pattern c1, and is composed of a pattern that does not appear during the repetition of the detection pattern c1. The delimiter pattern STP is also known to the stylus 2 in advance (before the stylus 2 detects the sensor controller 31). As an example, when the detection pattern c1 is configured by the combination “PM” of two bit string non-corresponding values “P” and “M” as described above, the delimiter pattern STP sets the bit string non-corresponding value “P” twice. It can be configured by a continuous pattern "PP". The configuration of the delimiter pattern STP and the detection pattern c1 may be reversed, the delimiter pattern may be configured by "PM", and the detection pattern c1 may be configured by "PP".

The pattern supply unit 61 holds the detection pattern c1 and the delimiter pattern STP, and is configured to output these in a predetermined order according to the instruction of the control signal ctrl_t1 supplied from the logic unit 70. Specifically, the detection pattern c1 is continuously and repeatedly output during a predetermined continuous transmission period, and the delimiter pattern STP is output immediately after the end of the continuous transmission period. As a result, the transmission of the pen activation signal is realized. The delimiter pattern STP may be output at the beginning of a command signal (described later) indicating a transmission instruction of a long burst signal.

The switch 62 has a function of selecting one of the pattern supply unit 61 and the MCU 80 based on the control signal ctrl_t2 supplied from the logic unit 70, and supplying the selected output to the diffusion processing unit 63. When the switch 62 selects the pattern supply unit 61, the pattern supply unit 61 supplies the detection pattern c1 or the delimiter pattern STP to the diffusion processing unit 63. On the other hand, when the switch 62 selects the MCU 80, the control information c2 is supplied from the MCU 80 to the diffusion processing unit 63.

The control information c2 is information indicating an instruction (command) to the stylus 2 and is generated by the MCU80. The command signal described above is composed of the control information c2. The control information c2 includes a symbol value (for example, 0 to 15) associated with a variable-length bit string, and the value is not shared in advance with the stylus 2, and the detection pattern c1 and the delimiter pattern STP. It's different.

The code sequence holding unit 64 has a function of generating and holding a diffusion code PN having a predetermined chip length having an autocorrelation characteristic based on the control signal ctrl_t3 supplied from the logic unit 70. The diffusion code PN held by the code string holding unit 64 is supplied to the diffusion processing unit 63.

The diffusion processing unit 63 modulates the diffusion code PN held by the code string holding unit 64 based on the symbol value (detection pattern c1, delimiter pattern STP, or control information c2) supplied via the switch 62. Therefore, it has a function of obtaining a transmission chip sequence having a predetermined chip length. The diffusion processing unit 63 is configured to supply the acquired transmission chip sequence to the transmission guard unit 65.

The transmission guard unit 65 is a guard required to switch between a transmission operation and a reception operation between the transmission period of the uplink signal and the reception period of the downlink signal based on the control signal ctrl_t4 supplied from the logic unit 70. It has a function to insert a period (a period in which both transmission and reception are not performed).

The receiving unit 50 is a circuit for receiving the finger detection signal transmitted by the transmitting unit 60 or the downlink signal transmitted by the stylus 2 based on the control signal ctrl_r of the logic unit 70. Specifically, it includes an amplifier circuit 51, a detection circuit 52, and an analog-to-digital (AD) converter 53.

The amplifier circuit 51 amplifies and outputs a signal (finger detection signal or downlink signal) supplied from the selection unit 40. The detection circuit 52 is a circuit that generates a voltage corresponding to the level of the output signal of the amplifier circuit 51. The AD converter 53 is a circuit that generates a digital signal by sampling the voltage output from the detection circuit 52 at predetermined time intervals. The digital signal output by the AD converter 53 is supplied to the MCU 80.

The signal reception process by the detection circuit 52 depends on the length of the period of the signal transmitted by the stylus 2 (first bit rate and second bit rate described later) according to the hover state or contact state of the stylus. It includes the process of detecting a signal for a period of time. Further, the MCU 80 acquires the data transmitted by the stylus 2 (switch information SW1 and the like described later) by determining the bit value of the signal by a demodulation method corresponding to the modulation method according to the hover state or the contact state. Further, when the frame transmitted by the stylus 2 contains an error detection code, the MCU 80 uses the error detection code when decoding the data transmitted by the stylus 2 (such as the switch information SW1 described later). Performs error detection (or error correction).

The selection unit 40 includes switches 44x and 44y and conductor selection circuits 41x and 41y.

The switches 44x and 44y are 1-circuit, 2-contact switch elements configured so that the common terminal and any one of the T terminal and the R terminal are connected, respectively. The common terminal of the switch 44x is connected to the conductor selection circuit 41x, the T terminal is connected to the output terminal of the transmitting unit 60, and the R terminal is connected to the input terminal of the receiving unit 50. Further, the common terminal of the switch 44y is connected to the conductor selection circuit 41y, the T terminal is connected to the output terminal of the transmitting unit 60, and the R terminal is connected to the input terminal of the receiving unit 50.

The conductor selection circuit 41x is a switch element for selectively connecting M linear electrodes 30X to the common terminal of the switch 44x. The conductor selection circuit 41x is configured so that a part or all of the M linear electrodes 30X can be simultaneously connected to the common terminal of the switch 44x.

The conductor selection circuit 41y is a switch element for selectively connecting N linear electrodes 30Y to the common terminal of the switch 44y. The conductor selection circuit 41y is also configured so that a part or all of the N linear electrodes 30Y can be simultaneously connected to the common terminal of the switch 44y.

Four control signals sTRx, sTRy, selX, and selY are supplied to the selection unit 40 from the logic unit 70. Specifically, the control signal sTRx is supplied to the switch 44x, the control signal sTRy is supplied to the switch 44y, the control signal selX is supplied to the conductor selection circuit 41x, and the control signal selY is supplied to the conductor selection circuit 41y. The logic unit 70 controls the selection unit 40 by using these control signals sTRx, sTRy, selX, and selY to transmit and receive a finger detection signal and transmit an uplink signal including a pen activation signal and a command signal. And the reception of the downlink signal is realized. The control of the selection unit 40 by the logic unit 70 will be described in more detail later.

The logic unit 70 and the MCU 80 are control units that control the transmission / reception operation of the sensor controller 31 by controlling the transmission unit 60, the reception unit 50, and the selection unit 40. Specifically, the MCU 80 is a microprocessor that has a ROM and a RAM inside and operates based on a predetermined program. On the other hand, the logic unit 70 is configured to output each of the above-mentioned control signals based on the control of the MCU 80. The MCU 80 also derives coordinate data x, y, etc. indicating the position of the finger F or the stylus 2 based on the digital signal supplied from the AD converter 53, and outputs the coordinate data x, y, etc. to the system controller of the electronic device 3. When the digital signal supplied from the AD converter 53 indicates a data signal, the process of acquiring the data Res represented by the digital signal and outputting it to the system controller of the electronic device 3 is performed. It is composed.

Hereinafter, the control of the selection unit 40 by the logic unit 70 will be specifically described.

First, in the logic unit 70 when transmitting and receiving the finger detection signal, N linear electrodes 30Y are sequentially connected to the output ends of the transmitting unit 60, and M linear electrodes 30X are sequentially connected to the receiving unit 50. The selection unit 40 is controlled by using the control signals sTRx, sTRy, selX, and selY so that they are connected to the input terminal. As a result, as shown in FIG. 1, a finger detection signal is sequentially supplied to each of the N linear electrodes 30Y, and each linear electrode 30X passes through an intersection with the linear electrodes 30Y. Since the receiving unit 50 can detect the finger detection signal that has arrived at, the touch detection by the finger F is realized.

The logic unit 70 when transmitting the uplink signal and receiving the downlink signal performs different processing depending on the detection state of the stylus 2 and the type of the downlink signal. Hereinafter, the types of downlink signals and the sequence of signal transmission / reception between the stylus 2 and the sensor controller 31 will be described first, and then the logic for transmitting the uplink signal and receiving the downlink signal. The operation of the unit 70 will be described in detail.

FIG. 3 is a diagram showing the types of downlink signals transmitted by the stylus 2 according to the embodiment of the present invention. As shown in the figure, the downlink signal includes a long burst signal, a burst signal, and a data signal. The long burst signal is a signal formed by continuously transmitting a signal having a predetermined waveform, which is a signal of a predetermined pattern known in advance between the stylus 2 and the sensor controller 31, for a predetermined time T1. The burst signal is a signal obtained by continuously transmitting a signal having the predetermined waveform over a predetermined time T4 shorter than the time T1. The data signal is a data signal obtained by modulating the signal having the predetermined waveform with data, and is typically transmitted following the burst signal within a time corresponding to the difference T1-T4 between the time T4 and the time T1. .. The actual transmission of the data signal may continue for a longer time than the difference T1-T4, which will be described later. A predetermined gap signal (not shown) for indicating a separation from the burst signal is inserted at the head of the burst signal. The type of downlink signal transmitted by the stylus 2 is selected according to an instruction by a command signal transmitted by the sensor controller 31.

4 to 6 are diagrams showing a sequence of signal transmission / reception between the stylus 2 and the sensor controller 31, FIG. 4 shows the case where the stylus 2 is above the uplink detection height AH, and FIG. In FIG. 6, the stylus 2 is inside the sensing range SR and the sensor controller 31 has not yet specified the position of the stylus 2 while the stylus 2 is inside the sensing range SR. Indicates after the position of the stylus 2 has been specified. Hereinafter, each case will be described in order.

<When the stylus 2 is above the uplink detection height AH>
FIG. 4A shows the case where the sensor controller 31 transmits the pen activation signal, and FIG. 4B shows the case where the sensor controller 31 requests the transmission of the long burst signal.

First, as shown in FIG. 4A, the sensor controller 31 transmits the pen activation signal over the time Ts (= t1-t0) from the time t0 to the time t1. This transmission is performed when the sensor controller 31 has not yet detected the stylus 2. As described above, the pen activation signal is a signal including the repetition of the detection pattern c1 and the trailing delimiter pattern STP. The stylus 2 intermittently performs the detection operation of the detection pattern c1 by intermittently performing the detection operation of the symbols (“P” and “M” in the above example) constituting the detection pattern c1, but the stylus 2 itself is up. When the link detection height is above the AH, the detection pattern c1 cannot be detected even by this detection operation. Therefore, the stylus 2 simply repeats the detection operation of the detection pattern c1.

Following the transmission of the pen activation signal, the sensor controller 31 describes a command signal (FIG. 4 to 6 and later in FIG. 10 as “CMD”” at time t2 after time t1 as shown in FIG. 4 (b). ) Is started to be transmitted. The time required to transmit the command signal is T0, which is shorter than the above-mentioned time Ts. When the stylus 2 has not been detected yet, the sensor controller 31 transmits a command signal indicating a long burst signal transmission instruction. However, since the stylus 2 above the uplink detection height AH cannot receive this command signal, it does not transmit a long burst signal in response to the command signal and simply repeats the detection operation of the detection pattern c1. ..

The sensor controller 31 performs a long burst signal detection operation after transmitting a command signal indicating a long burst signal transmission instruction. This detection operation corresponds to the first half of the full range scan described later, and is executed by sequentially using N linear electrodes 30Y. Details of the full range scan will be described later. Here, since the stylus 2 does not transmit the long burst signal, the sensor controller 31 does not naturally detect the long burst signal. The time that can be used as the detection operation of the long burst signal is the time T1 (= Ts−T0) corresponding to the difference between the time Ts and the time T0, but the long burst signal is sequentially used by sequentially using N linear electrodes 30Y. When the detection operation of is performed, the detection operation of the long burst signal is temporarily completed at the time t3 before the time t4 (= t2 + Ts) when the time T1 elapses. Therefore, when the long burst signal is not detected during this detection operation, the sensor controller 31 goes into a sleep state from the time t3 to the time t4. As a result, the power consumption of the sensor controller 31 is reduced. After the time t4, the transmission of the pen activation signal is repeated.

<The stage where the stylus 2 is inside the sensing range SR and the sensor controller 31 has not yet specified the position of the stylus 2>
FIG. 5A shows a case where the sensor controller 31 transmits a pen activation signal, and FIG. 5B shows a case where the sensor controller 31 receives a long burst signal transmitted by the stylus 2 using the linear electrode 30Y. 5 (c) shows a case where the sensor controller 31 receives the long burst signal transmitted by the stylus 2 by using the linear electrode 30X.

When the pen-down operation (time t6) is performed as shown in FIG. 5A, the stylus 2 can detect the detection pattern c1 by the subsequent detection operation of the detection pattern c1 (time t7). The stylus 2 that has detected the detection pattern c1 in this way continues the detection operation until the delimiter pattern STP is detected. When the delimiter pattern STP is detected, it synchronizes with the sensor controller 31 based on the detection time. Specifically, this synchronization is performed by creating a transmission / reception schedule, which will be described later.

In FIG. 5A, the pen-down operation is performed at time t6 between the time t5 when the transmission of the pen activation signal is started and the time t8 (= t5 + Ts) when the transmission of the pen activation signal is finished, and the pen-down operation is performed at time t8. An example in which the stylus 2 detects the detection pattern c1 at the time t7 before the arrival is shown. For example, when the pen-down operation is performed when the sensor controller 31 is performing the long burst signal detection operation (for example, FIG. 5 (FIG. 5). Even at the time t6') shown in b), the same process is executed only if the detection timing of the detection pattern c1 by the stylus 2 is slightly delayed.

Subsequently, as shown in FIG. 5B, when the sensor controller 31 starts transmitting a command signal indicating a long burst signal transmission instruction at time t9 after time t8, the stylus 2 receives this command signal and the time The long burst signal is continuously transmitted over the time T1 up to t10 (= t9 + Ts). The sensor controller 31 detects the stylus 2 by detecting the long burst signal transmitted in this way.

Specifically, first, as shown in FIG. 5B, a long burst signal detection operation is performed by sequentially using N linear electrodes 30Y (the first half of the full range scan described later). At this time, since the long burst signal is detected by any one or more linear electrodes 30Y, the sensor controller 31 stores the detection intensity of the long burst signal in each linear electrode 30Y. Next, as shown in FIG. 5C, the sensor controller 31 restarts the transmission of the command signal indicating the transmission instruction of the long burst signal at the time t11 after the time t10, and performs the long burst signal detection operation at the end of the transmission. Do it again. This detection operation is carried out by sequentially using M linear electrodes 30X until the time t12 (= t11 + Ts) (the latter half of the full range scan described later). Since the long burst signal is detected by any one or more linear electrodes 30X by this detection operation, the sensor controller 31 stores the detection intensity of the long burst signal in each linear electrode 30X. Then, the position coordinates of the stylus 2 on the touch surface are derived based on the detection intensity of the long burst signal at each linear electrode 30Y stored earlier and the detection intensity of the long burst signal at each linear electrode 30X stored this time.

<After the stylus 2 is inside the sensing range SR and the sensor controller 31 identifies the position of the stylus 2>
FIG. 6 shows the time when the burst signal and the data signal (the data to be transmitted is not a unique ID) are transmitted by the stylus 2 in the hover state. The case where the stylus 2 is in the above-mentioned contact state and the case where the data to be transmitted has a unique ID will be described in detail later.

As shown in FIG. 6, the sensor controller 31 that has specified the position of the stylus 2 starts transmitting a command signal indicating a data transmission instruction at the subsequent time t13. Upon receiving this, the stylus 2 first continuously transmits a burst signal over the time T4. The sensor controller 31 detects this burst signal and derives the position coordinates of the stylus 2 based on the detected burst signal. In the burst signal detection operation, only those of the M linear electrodes 30X and the N linear electrodes 30Y that are indicated to be near the stylus 2 by the position coordinates of the stylus 2 derived immediately before are sequentially selected. Performed using (sector scan described below). The stylus 2 transmits a data signal including the indicated data following the burst signal. The sensor controller 31 receives the data signal and decodes it to acquire the data transmitted by the stylus 2. The reception of the data signal is performed using only one linear electrode 30X or linear electrode 30Y corresponding to the position coordinates of the stylus 2 derived immediately before.

Returning to FIG. 2, the operation of the logic unit 70 when detecting the stylus 2 and performing bidirectional communication with the stylus 2 will be described in detail.

When transmitting a command signal indicating a pen activation signal and a long burst signal transmission instruction (FIGS. 4 (a) (b) and 5 (a) (b) (c)), the logic unit 70 has M lines. The selection unit 40 is controlled so that all of the linear electrodes 30X and / or all of the N linear electrodes 30Y are used at the same time. Specifically, the control signals sTRx, sTRy, selX, selY so that the output end of the transmission unit 60 is simultaneously connected to one or both of the M linear electrodes 30X and the N linear electrodes 30Y. 40 is used to control the selection unit 40. As a result, each of the command signal indicating the transmission instruction of the pen activation signal and the long burst signal is transmitted over the entire touch surface, so that the stylus 2 can be anywhere within the sensing range SR shown in FIG. , These signals can be received.

The logic unit 70 when the long burst signal is received at the stage where the stylus 2 has not been detected (FIGS. 4 (b) and 5 (b)) is also shown in FIGS. 4 (b) and 5 (b). As described above, the selection unit 40 is controlled so that the N linear electrodes 30Y are sequentially used. Specifically, the selection unit 40 is controlled by using the control signals sTRy and selY so that the N linear electrodes 30Y are sequentially connected to the input terminals of the reception unit 50. This allows the sensor controller 31 to receive the long burst signal transmitted by the stylus 2 wherever the stylus 2 is within the sensing range SR shown in FIG. 1, thereby detecting the stylus 2.

FIG. 7A is a diagram illustrating the operation of the sensor controller 31 in this case. As shown in the figure, the sensor controller 31 in this case sequentially scans N linear electrodes 30Y. The reason why M linear electrodes 30X are not scanned at this stage is that the entire surface of the sensor 30 can be scanned by using only N linear electrodes 30Y, and one electrode per electrode. This is to lengthen the scanning time.

After detecting the stylus 2 by receiving the long burst signal, when the long burst signal is received at the stage where the position coordinates of the stylus 2 have not been derived yet (FIG. 5 (c)), the logic unit 70 is shown in FIG. 5 (c). ), The selection unit 40 is controlled so that M linear electrodes 30X are sequentially used. Specifically, the selection unit 40 is controlled by using the control signals sTRx and selX so that the M linear electrodes 30X are sequentially connected to the input terminals of the reception unit 50. The sensor controller 31 derives the position coordinates of the stylus 2 on the touch surface as described above based on the result of this control and the detection result of the long burst signal by the N linear electrodes 30Y previously executed. To do.

FIG. 7B is a diagram illustrating the operation of the sensor controller 31 in this case. As shown in the figure, the sensor controller 31 in this case sequentially scans M linear electrodes 30X. In the present specification, a scan (first half) in which N linear electrodes 30Y shown in FIG. 7 (a) are sequentially used and a scan in which M linear electrodes 30X shown in FIG. 7 (b) are sequentially used (a scan (first half). Together with the latter half), it is called "full range scan".

When the command signal is transmitted at the stage after the position coordinates of the stylus 2 are derived (FIG. 6), the logic unit 70 is located near the stylus 2 among the M linear electrodes 30X and the N linear electrodes 30Y. The selection unit 40 is controlled so that only the ones in the above are used. Specifically, for example, assuming that the stylus 2 is located at the intersection of the j + 5th linear electrode 30X and the i + 5th linear electrode 30Y, for example, the range of 5 stylus 2 on each side, that is, the jth ~ The selection unit uses the control signals sTRx, sTRy, selX, and selY so that the j + 10th linear electrode 30X and the i-th to i + 10th linear electrodes 30Y are simultaneously connected to the output terminal of the transmission unit 60. 40 is controlled. As a result, the command signal can be transmitted using only the linear electrodes near the stylus 2, so that the power consumption required for transmitting the command signal can be reduced. Further, when the command signal is supplied to the equal hands placed on the touch surface, the ground potential supplied to the stylus 2 may increase, and as a result, the accuracy of detecting the uplink signal by the stylus 2 may decrease. However, by transmitting the command signal using only the linear electrode near the stylus 2 as described above, the possibility that the command signal is supplied to the equal hands is reduced, so that the uplink signal by the stylus 2 is reduced. It is possible to prevent a decrease in the detection accuracy of.

After deriving the position coordinates of the stylus 2, when receiving a normal burst signal that is not a long burst signal (FIG. 6), the logic unit 70 is of the M linear electrodes 30X and the N linear electrodes 30Y. The selection unit 40 is controlled so that only those near the stylus 2 are sequentially used. Specifically, for example, assuming that the stylus 2 is located at the intersection of the j + 5th linear electrode 30X and the i + 5th linear electrode 30Y, for example, as shown in FIG. 6, a range of 5 on each side is provided. That is, the control signals sTRx, sTRy, selX, so that the jth to j + 10th linear electrodes 30X and the ith to i + 10th linear electrodes 30Y are sequentially connected to the input ends of the receiving unit 50. The selection unit 40 is controlled using selY. As a result, the reception time per linear electrode can be lengthened, so that the burst signal can be received more reliably.

FIG. 7C is a diagram illustrating the operation of the sensor controller 31 in this case. In this example as well, the stylus 2 is assumed to be located at the intersection of the j + 5th linear electrode 30X and the i + 5th linear electrode 30Y. The sensor controller 31 according to this example sequentially connects only the 11 linear electrodes 30X from the jth to the j + 10th and the 11 linear electrodes 30Y from the ith to the i + 10th among the M × N linear electrodes. The scan is performed, and the position coordinates of the stylus 2 are derived based on the result. Hereinafter, a scan for redistributing (updating) the position coordinates of the stylus 2 once derived using both a part of the M linear electrodes 30X and a part of the N linear electrodes 30Y in this way is performed as a “sector”. Called "scan".

When receiving the data signal (FIG. 6), the logic unit 70 selects to use only one linear electrode 30X or linear electrode 30Y corresponding to the position of the stylus 2 derived by the immediately preceding burst signal. The unit 40 is controlled. Specifically, the selection unit 40 is selected by using the control signals sTRx, sTRy, selX, and selY so that the one linear electrode 30X or the linear electrode 30Y is connected to the input end of the receiving unit 50. Control. This makes it possible to fully utilize the data signal transmission time (= T1-T4) for transmitting data from the stylus 2 to the sensor controller 31.

The operation of the logic unit 70 when detecting the stylus 2 and performing bidirectional communication with the stylus 2 has been described above.

FIG. 8 is a block diagram showing a functional block of the stylus 2 according to the present embodiment. As shown in the figure, the stylus 2 includes a core body 20, an electrode 21, a switch 22, a pen pressure detection sensor 23 (pen pressure detection unit), and a signal processing unit 24.

The core body 20 is an insulating member that constitutes the pen tip of the stylus 2. The electrode 21 is a conductive member provided near the core body 20 (particularly near the tip), serves as an antenna for transmitting a downlink signal, and is transmitted from the sensor controller 31 via a coupling capacitance. It also serves as an antenna for receiving the uplink signal. The electrode for transmitting the downlink signal and the electrode for receiving the uplink signal may be the same or different.

The switch 22 is a switch that takes either an on / off state by a user's operation, such as a side switch provided on the side surface of the stylus 2 or a tail switch provided on the rear end portion. The pen pressure detection sensor 23 is a pressure sensor for detecting the pressure (pen pressure) applied to the tip of the core body 20.

The signal processing unit 24 receives the uplink signal from the sensor controller 31 via the electrode 21, performs processing according to the content thereof, generates a downlink signal to be transmitted to the sensor controller 31, and sets the electrode 21. It has a function of transmitting to the sensor controller 31 via the sensor controller 31. Specifically, it functionally includes a switching unit 76, a receiving unit 71, a transmitting unit 75, and a control unit 90. Hereinafter, each of these functional blocks will be described in order.

The switching unit 76 is a 1-circuit 2-contact switch element configured so that the common terminal and any one of the T terminal and the R terminal are connected. The common terminal of the switching unit 76 is connected to the electrode 21, the T terminal is connected to the output terminal of the transmitting unit 75, and the R terminal is connected to the input terminal of the receiving unit 71. The state of the switching unit 76 is controlled by the control signal SWC from the control unit 90. When the control unit 90 receives the uplink signal from the sensor controller 31, the control unit 90 controls the switching unit 76 by the control signal SWC so that the R terminal and the common terminal are connected. Further, when the downlink signal is transmitted to the sensor controller 31, the switching unit 76 is controlled by the control signal SWC so that the T terminal and the common terminal are connected. The control unit 90 consumes the stylus 2 after fixing the switching unit 76 to the state in which the R terminal and the common terminal are connected until the initial state, that is, until the stylus 2 detects the detection pattern c1 described above. Go to sleep to reduce power consumption.

The receiving unit 71 is a circuit that receives the signal supplied from the switching unit 76 (the signal arriving at the electrode 21) and decodes the value of the symbol included in the received signal, and is a waveform reproducing unit 71a and a correlation calculator. It is configured to include 71b. The receiving unit 71 is configured to be able to detect each of the above-mentioned detection pattern c1, delimiter pattern STP, and control information c2 by this decoding. In order to reduce the power consumption of the stylus 2, the receiving unit 71 performs a receiving operation only intermittently until the detection pattern c1 is detected.

The waveform reproduction unit 71a binarizes the level of the electric charge (voltage) induced in the electrode 21 with a clock several times (for example, four times) the chip rate of the diffusion code PN described above, and a binary sequence of positive and negative polarity values (for example, four times). It is formatted into a chip string) and output. The correlation calculator 71b stores the chip sequence output by the waveform reproduction unit 71a in a register, and shifts sequentially with the clock to spread code PN (or at least one of inversion and cyclic shift with respect to the spread code PN). The value of the symbol contained in the received signal is decoded by performing the correlation operation with the code obtained by applying.

The receiving unit 71 sequentially determines whether or not the value of the symbol decoded by the correlation calculator 71b indicates the above-mentioned detection pattern c1. When the detection pattern c1 is detected as a result, the presence of the sensor controller 31 is detected, and a start signal EN for enabling the control unit 90 to execute processing according to the command indicated by the command signal is set. Issue.

Further, when the detection pattern c1 is detected, the reception unit 71 continuously switches the reception operation from intermittent to continuous, and sequentially determines whether or not the decoded symbol value indicates the above-mentioned delimiter pattern STP. When the delimiter pattern STP is detected as a result, the receiving unit 71 outputs the detection time t2 to the control unit 90.

After detecting the delimiter pattern STP, the receiving unit 71 performs a command signal receiving operation to be transmitted by the sensor controller 31 according to scheduling (described later) by the control unit 90. Specifically, the values of a series of symbols decoded by the correlation calculator 71b during the reception operation are acquired as control information c2 and output to the control unit 90.

The control unit 90 is composed of a microprocessor (MCU) and is activated when the start signal EN is supplied from the reception unit 71, and then various signals are generated based on the detection time t2 supplied from the reception unit 71. Etc. to generate a transmission / reception schedule. Then, a process of generating a control signal SWC based on the generated transmission / reception schedule and supplying it to the switching unit 76, a process of controlling the receiving unit 71 so as to receive a command signal, and a control information c2 supplied from the receiving unit 71. The process of controlling the transmission unit 75 is performed based on the above.

For the control of the transmission unit 75 performed by the control unit 90, the type of signal transmitted to the sensor controller 31 based on the received command signal (any of the signals (A) to (F) shown in FIG. 10 to be described later). ), And when transmitting a data signal indicating the data, it includes acquiring the data instructed to be transmitted by the control information c2 and supplying it to the transmission unit 75. The data supplied to the transmission unit 75 includes a unique ID of the stylus 2 stored in a memory (not shown), data indicating the on / off state of the switch 22, data indicating the pen pressure detected by the pen pressure detection sensor 23, and the like. ..

Further, when the transmission unit 75 transmits a data signal, the control unit 90 determines whether the stylus 2 is in the contact state or the hover state, and controls the bit rate according to the result of the determination. Do. Specifically, when the determination result is in the contact state, at least a part of the data to be transmitted is transmitted to the transmission unit 75 at the first bit rate, and when the determination result is in the hover state, transmission is performed. At least a part of the target data is transmitted to the transmission unit 75 at a second bit rate smaller than the first bit rate. This point will be described in more detail later.

The transmission unit 75 is a circuit that generates a signal to be transmitted to the sensor controller 31 and supplies it to the electrode 21, and is composed of a modulation unit 73 and a booster circuit 74. By supplying the transmission signal to the electrode 21 in this way, the transmission unit 75 performs a process of transmitting a signal including the data to be transmitted by using the electrode 21.

The modulation unit 73 is a circuit that generates a carrier signal (for example, a square wave signal) having a predetermined frequency or a frequency that is controlled by the control unit 90, and outputs the signal as it is or after modulating it based on the control of the control unit 90. .. At the time of transmitting the long burst signal and the burst signal, the modulation unit 73 modulates and outputs the carrier signal as it is without modulating it or by modulating it with a pattern of known values shared with the sensor controller 31. As a result, the modulation unit 73 outputs a long burst signal before boosting and a burst signal before boosting. On the other hand, when the data signal is transmitted, the carrier signal is modulated (OK, PSK, etc.) by the data supplied from the control unit 90, and the resulting modulated signal is output. As a result, the data signal before boosting is output from the modulation unit 73.

The booster circuit 74 is a circuit that generates a long burst signal, a burst signal, and a data signal by boosting the output signal of the modulation unit 73 to a constant amplitude. The long burst signal, burst signal, and data signal generated by the booster circuit 74 are transmitted from the electrode 21 to the space via the switching unit 76.

The outline of the configuration and operation of the stylus 2 and the sensor controller 31 according to the present embodiment has been described above with reference to FIGS. 1 to 8. Next, the characteristic parts of the present invention in the operations of the stylus 2 and the sensor controller 31 will be described in detail with reference to FIGS. 9 to 19.

First, FIG. 9 is a processing flow diagram showing the entire processing performed by the sensor controller 31. However, the figure shows only the processing when the stylus 2 is in the hover state as an example. As shown in the figure, the sensor controller 31 is the same for each time Tr (for example, 16.67 ms, which is the reciprocal of 60 Hz) defined by the reciprocal of the display refresh rate of the display panel arranged together with the sensor 30. Is configured to repeat the operation of.

In each cycle, the sensor controller 31 first determines whether or not the stylus 2 is requested to transmit the unique ID (step S1). This request is made by transmitting a command signal indicating a transmission instruction of the unique ID.

When it is determined that the request is not made in step S1, the sensor controller 31 alternately executes the stylus detection process (step S2a) and the finger touch detection process (steps S3 and S4) four times each. Each stylus detection process is continuously executed for a time Ts (the same as the time Ts shown in FIGS. 4 to 6, for example, 2500 μs), and each finger touch detection process is continuously executed for a time Tf (for example, 1500 μs). .. The finger F is detected by using two finger touch detection processes (step S3 and step S4), which are executed discontinuously with the stylus detection process in between, as a position detection unit for one finger touch.

On the other hand, when it is determined that the request is made in step S1, the sensor controller 31 repeatedly executes only the stylus detection process (step S2b) four times. Each stylus detection process in this case is continuously executed for the time Ts + Tf. Since the finger touch detection process cannot be performed, the finger F shown in FIG. 1A cannot be used for input during this period. The reason why the duration of the stylus detection process is extended by restricting the input by the finger F in this way is that the size of the unique ID is large, and in order to transmit the entire unique ID from the stylus 2 to the sensor controller 31. This is because it takes a long time. It should be noted that the transmission of the unique ID may be performed once for each pen down, and it is considered that the user rarely inputs with the finger F at the same time as the pen down of the stylus 2, and the regulation time is the time Tr (for example, 16. Since it is only 67 ms), it is considered that the restriction of input by the finger F for transmitting the unique ID has almost no effect on the usability of the user.

In the following, a cycle having time Ts + Tf as one cycle is referred to as a “frame”, and a cycle having time Tr as one cycle (operation cycle of display processing of the display panel) is referred to as “super frame”. That is, the stylus 2 according to the present embodiment is configured to transmit the downlink signal in units of superframes and further transmit the downlink signal in units of frames. In the example of FIG. 9, one super frame includes four frames, but the number of frames in one super frame is not limited to four. Further, the "frame" and the "super frame" including a plurality of frames may be read as a "packet" and a "frame" including a plurality of packet transmissions, respectively.

FIG. 10 is a diagram showing a format of a downlink signal transmitted by the stylus 2 while the sensor controller 31 is executing the stylus detection process. As mentioned above, the downlink signal includes a long burst signal, a burst signal, and a data signal. FIG. 10 shows five types of data (A) to (E) with respect to the data transmitted by the data signal. In the following, for the sake of simplicity, the term "data transmission" may be used to refer to the transmission of a data signal.

The data (D) and (E) that are hatched downward in FIG. 10 are transmitted when the stylus 2 is in contact with each other, and are transmitted by the stylus 2 at the first bit rate. On the other hand, the data (B) and (C) are transmitted when the stylus 2 is in the hover state, and are transmitted by the stylus 2 at a second bit rate smaller than the first bit rate. Further, the data (A) is transmitted regardless of whether the stylus 2 is in the hover state or the contact state, and is transmitted by the stylus 2 at the second bit rate. The present invention has a main feature in that the bit rates of the data (A) to (E) are controlled in this way.

Hereinafter, the operations of the sensor controller 31 and the stylus 2 will be described in detail with reference to FIG. 10 and a processing flow diagram showing the processing of the sensor controller 31 and the stylus 2.

FIG. 11 is a processing flow diagram showing the reception processing of the uplink signal and the transmission processing of the downlink signal by the stylus 2. Hereinafter, the operation of each unit (particularly, the receiving unit 71, the transmitting unit 75, and the controlling unit 90) of the stylus 2 shown in FIG. 8 will be described in detail with reference to FIG. 11.

First, although not shown, the control unit 90 of the stylus 2 stores a state flag indicating its own state. The state indicated by this state flag includes a sensor controller undetected state (= 0) and a sensor controller detected state (= 1). The control unit 90 controls the transmission unit 75 to transmit signals in frame units by referring to this state flag at the start timing of the frame described above (step S70).

When the state flag referred to in step S70 is "0", the receiving unit 71 of the stylus 2 first enters the receiving operation hibernation state (step S71). Then, after the predetermined time has elapsed, the detection of the above-mentioned detection pattern c1 is tried (step S72). The pause period in step S71 is provided in order to reduce the power consumption of the stylus 2 by intermittently performing the detection operation of the detection pattern c1.

Next, the receiving unit 71 determines whether or not the detection pattern c1 is detected by the trial in step S72 (step S73). As a result, if it is determined that it has not been detected, the process returns to step S70. On the other hand, when it is determined that the detection is detected, the receiving unit 71 activates the control unit 90 by issuing the activation signal EN shown in FIG. 8, while the detection pattern c1 is detected until the above-mentioned delimiter pattern STP is detected. And the detection operation of the symbols constituting the delimiter pattern STP is continued (step S74). Then, when the delimiter pattern STP is detected, the receiving unit 71 outputs the detection time t2 (FIG. 8) to the control unit 90. The control unit 90 that has received the detection time t2 performs a process of synchronizing with the sensor controller 31 based on the detection time t2 (specifically, the process of generating the transmission / reception schedule described above) (step S75), and then sets the status flag. “1” is set (step S76), and the process returns to step S70.

When the state flag referred to in step S70 is "1", the control unit 90 first performs a command signal detection operation (step S80). Specifically, this detection operation is an operation of receiving the control information c2 (see FIG. 8) from the receiving unit 71, and is performed over the time T0 (for example, 200 μs) shown in FIGS. 4 to 6. Next, the control unit 90 determines whether or not the command signal is detected by the detection operation in step S80 (step S81), and if it is determined that the command signal is not detected, sets "0" in the state flag (step). S82), the process is returned to step S70. This step S82 is a process when the stylus 2 cannot detect the uplink signal because, for example, the stylus 2 is separated from the uplink detection height AH shown in FIG.

On the other hand, when it is determined in step S81 that the command signal is detected, the control unit 90 determines the content of the detected command signal (content of the instruction from the sensor controller 31) (step S83). Specifically, the contents of the command signal include a long burst signal transmission instruction (LB), a unique ID transmission instruction (ID), and a data transmission instruction other than the unique ID (DT).

When it is determined in step S83 that the content of the command signal is the transmission instruction (LB) of the long burst signal, the control unit 90 causes the transmission unit 75 to transmit the long burst signal (step S84). More specifically, as shown in FIG. 10 (1), the control unit 90 receives the command signal transmitted over the time T0 from the time t0 to the time t1, and then the time T1 from the time t1 to the time t5. The transmission unit 75 is controlled so as to transmit a long burst signal over a period of time. As described with reference to FIG. 4, T1 = Ts−T0. The control unit 90 then returns the process to step S70, as shown in FIG.

When it is determined in step S83 that the content of the command signal is the transmission instruction (ID) of the unique ID, the control unit 90 first determines whether or not the stylus 2 is in the hover state (step S85). This determination is performed by confirming the pen pressure detected by the pen pressure detection sensor 23 shown in FIG. That is, the control unit 90 determines that the pen pressure is in the hover state when the pen pressure detected by the pen pressure detection sensor 23 is zero, and when the pen pressure detected by the pen pressure detection sensor 23 is greater than zero. It is judged that the hover state is not (contact state).

When it is determined in step S85 that the hover state is reached, the control unit 90 causes the transmission unit 75 to first transmit a burst signal (step S86), and then continues the data (A) and the data (B) by the second transmission method. (Steps S87 and S88).

As shown in FIG. 10 (2), the data (A) is a state information State composed of a burst signal, a predetermined start flag Start, and 1-bit information indicating the determination result (hover state or contact state) of step S85. It is data composed including and. The state information State in this case is information indicating the hover state. The control unit 90 transmits the burst signal over the time T4 (see FIG. 3) from the time t1 to the time t2, and during the subsequent time t3, the start flag Start and the state information State are set by the second transmission method. The transmission unit 75 is controlled so as to continuously transmit in order. The second transmission method is a method of transmitting each bit at the above-mentioned second bit rate, and is compared to the first time (for example, 30 μs) by the first transmission method described later for transmitting each bit. A long second time (eg 90 μs) is applied. A gap time having a predetermined time length is provided between the burst signal and the start flag Start.

As shown in FIG. 10 (2), the data (B) is data including a mode information model, a frame number FN, a part of a unique ID, and a checksum CS. The control unit 90 transmits these information in the above order by the same second transmission method as the data (A) from immediately after the time t3 at which the transmission of the state information State ends to the end time t7 of the frame. Controls the transmitter 75. According to this, the time required from the start of receiving the command signal to the end of transmission of the data (B) becomes Ts + Tf, and the time for finger touch detection shown in FIG. 9 cannot be taken. Therefore, the sensor controller 31 in this case is a finger. Touch detection cannot be performed.

The components of the data (B) will be described in detail. First, the mode information model is 1-bit information indicating the type (unique ID or other data) of the data to be sent from now on. In the data (B), the type indicated by the mode information model is "unique ID".

The frame number FN is 2-bit information indicating the order of frames in the super frame, and indicates which frame in one super frame the stylus detection process currently being executed is performed. There is.

The unique ID is 52-bit information that differs for each stylus 2. The 52-bit information is very large in size as the information transmitted by the stylus 2, and cannot be transmitted in one frame, so that the information is divided into each frame in one super frame and transmitted. Specifically, it is divided into 13 bits and transmitted over all 4 frames in one super frame. The frame number FN is used to restore the unique ID thus divided and transmitted in the sensor controller 31.

Inversion bits Op are arranged in the middle and immediately after the unique ID. The inverting bit Op is a bit obtained by inverting the last bit of a predetermined number of bits, and the control unit 90 controls the transmission unit 75 to transmit the inverting bit Op immediately after the predetermined number of bits. In the example of FIG. 10 (2), one inverting bit Op is arranged immediately after the unique ID for 6 bits, and then one immediately after the unique ID for 7 bits. The inverting bit Op is installed to prevent the same bit from continuing more than a predetermined number.

The checksum CS is an error detection code calculated based on the data (for example, 13-bit unique ID) included in the same data (B). The number of bits of the checksum CS is arbitrary, but is set to 3 bits in FIG. The control unit 90 calculates the checksum CS at the time of generating the data (B), for example, and arranges the checksum CS at the end of the data (B). After the unique ID is received, the sensor controller 31 calculates the checksum CS by itself and compares it with the received checksum CS to determine whether or not the unique ID has been normally received.

Return to FIG. When it is determined in step S85 that the contact state is reached, the control unit 90 causes the transmission unit 75 to first transmit a burst signal (step S89), and then transmit the data (A) by the second transmission method (step S90). Then, the data (D) is transmitted by the first transmission method (step S91).

The contents of the data (A) are as described above. However, the state information State in this case is information indicating the contact state.

As shown in FIG. 10 (5), the data (D) is a signal including a mode information model, a frame number FN, a part of a unique ID, and a checksum CS. The type indicated by the mode information model in this case is a "unique ID". Further, in the data (D), one place at the beginning of the data (D) and two places in the middle of the unique ID (more specifically, immediately after the unique ID for 3 bits, and for 6 bits thereafter. Inversion bits Op are arranged at a total of three places (immediately after the unique ID).

The number of bits of the unique ID transmitted by one data (D) is 12 bits. The checksum CS in this case is, for example, a 3-bit error detection code calculated based on 12-bit unique IDs included in the same data (D). The unique ID is divided and transmitted over all four frames in one super frame as in the case of the data (B), but since the total number of bits of the unique ID is 52 bits as described above, 12 per frame. With bits, 4 bits are insufficient. The 4-bit unique ID is transmitted as the serial number SN in the data (E) described later.

The control unit 90 transmits the information constituting the data (D) in the above order by the first transmission method from immediately after the time t3 when the transmission of the state information State ends to the time t6. Control 75. The first transmission method is a method of transmitting each bit at the above-mentioned first bit rate, and it takes, for example, 30 μs to transmit each bit. This time length of 30 μs is a value of 1/3 of the above-mentioned second transmission method. Further, the time t6 is a time slightly after the end time t5 of the stylus detection process when transmitting the long burst signal (time before the end time t7 of the frame), and the burst signal and data (A). , And the time T3 (= t6-t1) required for transmitting the data (D) is slightly longer than the time T1 required for transmitting the long burst signal. According to this, although a part of the finger touch detection time shown in FIG. 9 is used for transmitting and receiving data (D), the erosion to the finger touch detection time is very small. In this case, the finger touch detection can be executed by the sensor controller 31.

Return to FIG. When it is determined in step S83 that the content of the command signal is a data transmission instruction (DT) other than the unique ID, the control unit 90 first determines whether or not the stylus 2 is in the hover state (step S92). .. Since the details of the determination in step S92 are the same as those in step S85, detailed description thereof will be omitted.

When it is determined in step S92 that the hover state is reached, the control unit 90 causes the transmission unit 75 to first transmit a burst signal (step S93), and then continues the data (A) and the data (C) by the second transmission method. (Steps S94 and S95).

The contents of the data (A) are as described above. However, the state information State in this case is information indicating the hover state.

The data (C) is a signal including the mode information Mode, the two switch information SW1 and SW2, and the battery information Bat as shown in FIG. 10 (3), or is shown in FIG. 10 (4). As described above, it is a signal including only the mode information Mode. The type indicated by the mode information model in this case is "other data". Further, the first switch information SW1 is 1-bit information (first digital value) indicating an on / off state of the switch 22 shown in FIG. As can be understood from the description of FIG. 10 (3), the state information State is arranged in front of the switch information SW1 in one frame. The second switch information SW2 is reserved in advance in the present embodiment and is not actually used. The battery information Bat is 1-bit information indicating the remaining amount of the drive battery (not shown) of the stylus 2. This battery information bat is configured to represent the remaining battery level by the frequency of becoming "1" in a plurality of transmissions.

The control unit 90 causes the transmission unit 75 to transmit the data (C) shown in FIG. 10 (3) in the first frame and the third frame in one super frame, while 2 in one super frame. In the fourth frame and the fourth frame, the data (C) shown in FIG. 10 (4) is transmitted to the transmission unit 75. The reason why the transmission contents are changed depending on the frame in this way is that the reduction of the power consumption of the stylus 2 is prioritized in view of the fact that it is not necessary to transmit the switch information SW1 and SW2 and the battery information Bat at a high rate. is there.

Regarding the data (C) shown in FIG. 10 (3), the control unit 90 transmits the data (C) by the second transmission method between the time immediately after the time t3 at which the transmission of the state information State ends and the time t5. The transmission unit 75 is controlled so as to transmit each of the constituent information in the above order. Therefore, the time required for transmitting the burst signal, the data (A), and the data (C) is T1 which is the same as the time required for transmitting the long burst signal. On the other hand, regarding the data (C) shown in FIG. 10 (4), the second transmission is performed between the time immediately after the time t3 when the transmission of the state information State is completed and the time t4 (the time between the time t3 and the time t5). According to the method, the transmission unit 75 is controlled so as to transmit the mode information mode constituting the data (C). In the latter case, the control unit 90 goes to sleep from time t4 to time t5, and the power consumption of the stylus 2 is reduced accordingly.

Return to FIG. When it is determined in step S92 that the contact state is established, the control unit 90 causes the transmission unit 75 to first transmit a burst signal (step S97), and then transmit the data (A) by the second transmission method (step S98). , And then the data (E) is transmitted by the first transmission method (step S99).

The contents of the data (A) are as described above. However, the state information State in this case is information indicating the contact state.

As shown in FIG. 10 (6), the data (E) includes a mode information model, a frame number FN, a serial number SN, a reservation information RS, a pen pressure data P, a switch information SW1, and a checksum CS. It is a signal composed of and. The type indicated by the mode information model in this case is "other data". Further, in the data (E), the inversion bit Op is provided in a total of three places, one at the beginning of the data (E), one immediately after the reservation information RS, and one immediately after the pen pressure data P. Be placed.

The serial number SN is information for 4 bits out of 52 bits constituting the unique ID as described above, and is for the sensor controller 31 to identify a plurality of styluses 2 in use together with the same sensor controller 31. used. The serial number SN may be information for specifying the pen tip setting type indicating the setting state (pencil, brush, etc.) of the pen tip of the stylus 2. Like the unique ID, the serial number SN is divided and transmitted bit by bit over all four frames in one super frame. The sensor controller 31 stores 48 bits received by the data (D) and combines them with the 4 bits received by the data (E) to obtain the entire unique ID.

The reservation information RS is information that can be freely set by the vendor of the stylus 2, and 2 bits are secured.

The pen pressure data P is 12-bit data (second digital value) indicating the pen pressure detected by the pen pressure detection sensor 23, and is two consecutive frames (more specifically, within one super frame). The 1st and 2nd frames or the 3rd and 4th frames are arranged in 6 bits each.

The control unit 90 transmits the information constituting the data (E) in the above order by the first transmission method from immediately after the time t3 when the transmission of the state information State ends to the time t6. Control 75. Therefore, a part of the finger touch detection time shown in FIG. 9 is used for transmitting and receiving the data (E), but as in the case of the data (D), the finger touch detection time is eroded. Since the number is very small, it is possible to execute finger touch detection by the sensor controller 31.

As described above, the control unit 90 performs an operation of selectively transmitting the data (A) to (E) to the transmission unit 75 in response to the instruction of the sensor controller 31, and at that time, the state (contact) of the stylus 2 is performed. The bit rate is also controlled according to the state (state or hover state). Specifically, the bit rate of the data (B) and (C) transmitted in the hover state (the second bit rate described above) is changed to the bit rate of the data (D) and (E) transmitted in the contact state (described above). The value is set to be smaller than that of the first bit rate). Further, the control unit 90 causes the transmission unit 75 to transmit the data (A) at the second bit rate as in the data (B) and (C) transmitted in the hover state. Note that FIG. 10 shows an example in which the ratio of the first bit rate to the second bit rate is 3: 1, but this ratio can be changed as appropriate. The control unit 90 controls the bit rate in this way in order to improve the noise immunity in the hover state where the S / N ratio of the downlink signal tends to deteriorate, and particularly for the data (A). This is to ensure that the sensor controller 31 can receive the state information state. This point will be explained in detail later.

Next, FIGS. 12 and 13 are processing flow diagrams showing the uplink signal transmission process and the downlink signal reception process by the sensor controller 31. Hereinafter, the processing of the sensor controller 31 corresponding to the processing of the stylus 2 shown in FIG. 11 will be described with reference to FIGS. 12 and 13.

Like the stylus 2, the sensor controller 31 stores a state flag indicating its own state. The states indicated by this status flag include a stylus not detected and pen activation signal transmission waiting state (= 0), a stylus not detected and a response waiting state for the pen activation signal (= 1), and a stylus detected and position undetected. The derivation state (= 2), the stylus position derived state and the unique ID unreceived state (= 3), and the unique ID received state (= 4) are included. The sensor controller 31 first refers to this status flag (step S10).

When the state flag referred to in step S10 is "0", the sensor controller 31 transmits a pen activation signal over the time Ts shown in FIG. 9 and the like (step S11). Specifically, the repetition of the detection pattern c1 and the delimiter pattern STP are transmitted. The sensor controller 31 that has completed the continuous transmission of the pen activation signal performs the finger touch detection process (step S12) for the time Tf shown in FIG. 9 and the like, and then sets the status flag to “1” (step S13). , Return the process to step S10. In FIG. 12, it is assumed that step S13 is performed after step S12, but these may be executed in parallel. This relationship is the same for other finger touch detection processes (steps S16, S23, S41.S54, S61) described later and subsequent processes (for example, each process of steps S17 to S20 for step S16). ..

When the state flag referred to in step S10 is "1", the sensor controller 31 first transmits a command signal indicating a long burst signal transmission instruction (LB request) (step S14). The time T0 described above is required to transmit various command signals including this command signal. After that, the sensor controller 31 performs the long burst signal reception operation shown in FIG. 10 over the time T1 described above (step S15). This reception operation is performed by the first half of the full range scan described with reference to FIG. 7A.

When the time T1 elapses and the operation of receiving the long burst signal is completed, the sensor controller 31 determines whether or not the long burst signal has been received while performing the finger touch detection process (step S16) over the time Tf (step S16). Step S17). As a result, if it is determined that the signal has not been received, the status flag is set to "0" (step S18), and the process returns to step S10. This step S18 is a process when the sensor controller 31 cannot receive the downlink signal because, for example, the stylus 2 is outside the sensing range SR shown in FIG. On the other hand, when it is determined that the signal has been received in step S17, the sensor controller 31 sets the status flag to "2" (step S19), further determines the command to be transmitted to the stylus 2 (step S20), and then steps. The process is returned to S10. The command determined here is a long burst signal transmission instruction (LB).

When the state flag referred to in step S10 is "2", the sensor controller 31 first retransmits a command signal indicating a long burst signal transmission instruction (LB request) (step S21). After that, the sensor controller 31 re-executes the operation of receiving the long burst signal over the time T1 (step S22). This reception operation is performed by the latter half of the full range scan described with reference to FIG. 7 (b). If the first half operation (step S15) and the second half operation (step S22) of the full range scan can be executed during one time T1, these two steps S15 and S22 are executed by one process. You may.

When the time T1 elapses and the long burst signal reception operation is completed, the sensor controller 31 determines whether or not the long burst signal has been received while performing the finger touch detection process (step S23) over the time Tf (step S23). Step S24). As a result, if it is determined that the signal has not been received, the status flag is set to "0" (step S25), and the process is returned to step S10. This step S25 is a process when the sensor controller 31 cannot receive the downlink signal because, for example, the stylus 2 has moved out of the sensing range SR shown in FIG. On the other hand, when it is determined that the signal has been received in step S24, the sensor controller 31 sets the state flag to "3" (step S26), and also sets the detection result of the long burst signal in step S15 and the long burst in step S22. The position of the stylus 2 is derived based on the signal detection result (step S27). Then, after determining the command to be transmitted to the stylus 2 (step S28), the process returns to step S10. The command determined here is not only a transmission instruction (ID request) of a unique ID, but also plays a role of a normal burst signal transmission instruction that is not a long burst signal. The point that the command also plays the role of the burst signal transmission instruction is the same for the command to be transmitted in step S50 described later (the command indicating the data transmission instruction (DT request) other than the unique ID).

When the state flag referred to in step S10 is "3", the sensor controller 31 transmits a command signal indicating the command determined in step S28 or steps S37 and S45 described later (step S30). After that, the sensor controller 31 sequentially receives the burst signal and the data (A) (steps S31a and S31b), and when the burst signal is received, the received burst signals are connected to the linear electrodes 30X and 30Y. The position coordinates of the stylus 2 are derived based on the detection intensity.

The burst signal reception operation in step S31a is performed by the sector scan described with reference to FIG. 7 (c). On the other hand, the data (A) receiving operation in step S31b is performed using one linear electrode 30X or linear electrode 30Y selected based on the position coordinates derived based on the detection intensity of the burst signal. Further, the sensor controller 31 acquires data (A) by demodulating the received signal by the first demodulation method corresponding to the second bit rate described above. These points are the same when the burst signal and the data (A) are detected in steps S51a and S51b described later.

When the sensor controller 31 finishes receiving the burst signal and the data (A), the stylus 2 is in the hover state by checking the state information State included in the data (A). (Step S32). Then, when it is determined that the hover state is reached, the data (B) reception operation is performed (step S33). Since the data (B) is continuously transmitted until the end time of the frame as described with reference to FIG. 10, the sensor controller 31 in this case does not perform the finger touch detection process.

The reception operation in step S33 is performed using one linear electrode 30X or linear electrode 30Y selected based on the position coordinates derived in step S31, as in the data (A) reception operation. This point also applies to the reception operations (steps S40, S53, S60) of the data (C) to (E) described later. By doing so, it becomes possible to fully utilize the detection period of the data signal, so that more data can be transmitted from the sensor controller 31 to the stylus 2. Further, the sensor controller 31 acquires data (B) by demodulating the received signal by the first demodulation method described above. This point is the same for the data (C) reception operation (step S53) described later.

When the sensor controller 31 ends the data (B) reception operation, the sensor controller 31 determines whether or not the burst signal, the data (A), or the data (B) has been received (step S34). As a result, if it is determined that none of them have been received, the state flag is set to "0" (step S35), and the process is returned to step S10. This step S35 is a process when the sensor controller 31 cannot receive the downlink signal because, for example, the stylus 2 has moved out of the sensing range SR shown in FIG. On the other hand, when it is determined in step S34 that any of the data has been received, it is determined whether or not all the fragments of the unique ID (13-bit data) that can be received through the data (B) have been received (that is, 52 bits). (Step S36). Then, if it is determined that the stylus has not been received yet (there is a remainder), a command indicating a transmission instruction (ID request) of the unique ID is determined as a command to be transmitted to the stylus 2 (step S37). , Return the process to step S10. On the other hand, when it is determined in step S36 that all data has been received (there is no remaining data), "4" is set in the status flag (step S38), and a transmission instruction (DT request) for data other than the unique ID is indicated. After determining the command as the command to be transmitted to the stylus 2 (step S39), the process returns to step S10.

Here, although not shown, the sensor controller 31 performs a process of restoring and storing the unique ID by combining a plurality of pieces of the received unique ID in parallel with the execution of steps S38 and S39. In this case, the sensor controller 31 determines the order of coupling based on the frame number FN transmitted with each fragment.

When it is determined in step S32 that the sensor controller 31 is not in the hover state (in the contact state), the sensor controller 31 performs a data (D) reception operation (step S40). As shown in FIG. 13, this reception operation is performed in a form that slightly bites into the time originally reserved for finger touch detection, but the sensor controller 31 utilizes the remaining time after the end of step S40. Then, the finger touch detection process is performed (step S41). The sensor controller 31 acquires data (D) by demodulating the received signal by the second demodulation method corresponding to the first bit rate described above. This point is the same for the data (E) reception operation (step S60) described later. The second demodulation method is a demodulation method having a higher bit error rate than the first demodulation method.

When the sensor controller 31 ends the data (D) reception operation, the sensor controller 31 determines whether or not the burst signal, the data (A), or the data (D) has been received (step S42). As a result, if it is determined that none of them have been received, the state flag is set to "0" (step S43), and the process is returned to step S10. This step S43 is a process when the sensor controller 31 cannot receive the downlink signal because, for example, the stylus 2 has moved out of the sensing range SR shown in FIG. On the other hand, when it is determined in step S42 that any of them has been received, the sensor controller 31 has received all (that is, 48 bits) of unique ID fragments (12-bit data) that can be received through the data (D). Whether or not it is determined (step S44). Then, if it is determined that the stylus has not been received yet (there is a remainder), a command indicating a transmission instruction (ID request) of the unique ID is determined as a command to be transmitted to the stylus 2 (step S45). , Return the process to step S10. On the other hand, when it is determined in step S44 that all data has been received (there is no remaining data), "4" is set in the status flag (step S46), and a transmission instruction (DT request) for data other than the unique ID is indicated. After determining the command as the command to be transmitted to the stylus 2 (step S47), the process returns to step S10.

When the state flag referred to in step S10 is "4", the sensor controller 31 transmits a command signal indicating a command determined in steps S39 and S47 or steps S57 and S64 described later (step S50). After that, the sensor controller 31 sequentially receives the burst signal and the data (A) (steps S51a and S51b), and when the burst signal is received, the received burst signals are connected to the linear electrodes 30X and 30Y. The position coordinates of the stylus 2 are derived based on the detection intensity.

When the sensor controller 31 finishes receiving the burst signal and the data (A), the stylus 2 is in the hover state by checking the state information State included in the data (A). (Step S52). Then, when it is determined that the hover state is reached, the data (C) reception operation is performed (step S53).

When the sensor controller 31 ends the data (C) reception operation, whether or not the sensor controller 31 has received the burst signal, the data (A), or the data (C) while performing the finger touch detection process (step S54) over the time Tf. (Step S55). As a result, if it is determined that none of them have been received, the state flag is set to "0" (step S56), and the process is returned to step S10. This step S56 is a process when the sensor controller 31 cannot receive the downlink signal because, for example, the stylus 2 has moved out of the sensing range SR shown in FIG. On the other hand, when it is determined in step S55 that any of the data has been received, a command indicating a data transmission instruction (DT request) other than the unique ID is determined as a command to be transmitted to the stylus 2 next (step S57). , Return the process to step S10.

When it is determined in step S52 that the sensor controller 31 is not in the hover state (in the contact state), the sensor controller 31 performs a data (E) reception operation (step S60). As shown in FIG. 13, this reception operation is performed in a form that slightly bites into the time originally reserved for finger touch detection, but the sensor controller 31 utilizes the remaining time after the end of step S60. Then, the finger touch detection process is performed (step S61).

When the sensor controller 31 ends the data (E) reception operation, the sensor controller 31 determines whether or not the burst signal, the data (A), or the data (E) has been received (step S62). As a result, if it is determined that none of them have been received, the state flag is set to "0" (step S63), and the process is returned to step S10. This step S63 is a process when the sensor controller 31 cannot receive the downlink signal because, for example, the stylus 2 has moved out of the sensing range SR shown in FIG. On the other hand, when it is determined in step S62 that any of the data has been received, a command indicating a data transmission instruction (DT request) other than the unique ID is determined as a command to be transmitted to the stylus 2 next (step S64). , Return the process to step S10.

Here, although not shown, whether or not the sensor controller 31 has received all the fragments of the serial number SN (data for one bit) that can be received through the data (E) in parallel with the execution of step S64. Is determined. Then, when it is determined that all of them have been received, the process of restoring and storing the unique ID by combining the plurality of fragments of the received serial number SN and the plurality of fragments of the unique ID received in step S40 repeatedly executed. I do. In this case, the sensor controller 31 determines the order of these combinations based on the frame number FN transmitted with each fragment of the serial number SN, and these are based on the frame number FN transmitted with each fragment of the unique ID. Determine the order of joining. The position of the serial number SN in the unique ID is determined in advance by the specifications.

The method of restoring such information is the same for the pen pressure data P. That is, as described above, the stylus 2 divides the pen pressure data P into a plurality of frames and transmits the pen pressure data P, but the sensor controller 31 receives the pen pressure data P based on the frame number FN received together with each fragment of the pen pressure data P. It is possible to determine the binding order of a plurality of fragments of the pen pressure data P.

The processing of the sensor controller 31 corresponding to the processing of the stylus 2 shown in FIG. 11 has been described above. Next, the control unit 90 of the stylus 2 sets the bit rates (second bit rates) of the data (B) (C) and the data (A) transmitted in the hover state to the data (D) transmitted in the contact state. ) A specific method for making the value smaller than the bit rate (first bit rate) of (E) will be described in detail with reference to FIGS. 14 to 19.

FIG. 14 is a diagram showing a first example of a method of transmitting data (A) to (C) and data (D) (E) by the stylus 2. The transmission unit 75 of the stylus 2 according to this example is configured to modulate the carrier signal with the data to be transmitted by using the same modulation method regardless of the state of the stylus 2. Specifically, the carrier signal is modulated by the data to be transmitted by using amplitude modulation (including on-off modulation) or phase modulation using a fixed frequency carrier signal. Then, the control unit 90 sets the modulation rate of the data (D) and (E) (the number of modulations per unit time) to be larger than the modulation rate of the data (A) to (C) (in the example of FIG. 14). Control the transmitter 75 (so that it is 4: 1). As a result, the bit rate (first bit rate) of the data (D) (E) becomes larger than the bit rate (second bit rate) of the data (A) to (C). While enabling data transmission of a large amount of information such as pen pressure data P different from the switch information SW1 of 10, the first digital value (switch information SW1 etc. in FIG. 10) transmitted in the hover state is transmitted in a contact state. It is possible to reduce the demodulation error in the sensor controller 31 and the bit value determination error rate as compared with the case where the data is calculated. The modulation rate may be changed by, for example, increasing the transmission time of amplitude modulation or phase modulation by the switch information SW1 at the time of hovering as compared with the contact state.

FIG. 15 is a diagram showing a second example of a method of transmitting data (A) to (C) and data (D) (E) by the stylus 2. The control unit 90 according to this example transmits each bit of the data to be transmitted so that the data (D) and (E) are transmitted only once, while the data (A) to (C) are repeatedly transmitted four times. Control 75. This control is for reducing the modulation rate in the hover state as shown in FIG. 14, even if the coding method is to provide more redundancy in the hover state (used for error correction). May be good. Therefore, from the viewpoint of the amount of data substantially transmitted, the bit rate (first bit rate) of the data (D) (E) is the bit rate (second bit) of the data (A) to (C). Since it is larger than the rate), this example also enables the transmission of a large amount of information such as pen pressure data P, which is different from the switch information SW1 in the contact state, and is transmitted in the hover state. It is possible to reduce the determination error rate in the sensor controller 31 as compared with the case where the digital value (switch information SW1 in FIG. 10 or the like) is transmitted in the contact state.
As a coding process for providing redundancy in error correction, if the hover state is larger than the contact state, the ratio does not necessarily have to be N: 1 (N is an integer of 2 or more). For example, the same information may be repeated M times (M is an integer of 2 or more) at the time of contact, and the same information may be repeated N times (N> M) in the hover state.

FIG. 16 is a diagram showing a third example of a method of transmitting data (A) to (C) and data (D) (E) by the stylus 2. The control unit 90 according to this example controls the transmission unit 75 so as to add a checksum CS (first error detection code) to the end of the data signal. Then, when the data (A) to (C) are transmitted, the number of bits of the checksum CS to be added is increased as compared with the case where the data (D) and (E) are transmitted. Specifically, in the data (A) to (C), a checksum CS having a size of 1 minute for the transmission time is added to the data having a size (n bits) for the transmission time td, and the data (D) In (E), a checksum CS having a size corresponding to the transmission time ct2 (<tk1) is added. Since the bit rate is nothing but the number of transmission bits per unit time, the bit rate (first bit rate) of the data (A) to (C) in this case is n / (td + tk2), and the data (A) to The bit rate (second bit rate) of (C) is n / (td + tc1). Since tc1> tc2, the latter (= n / (td + tk1)) is smaller than the former (= n / (td + tk2)). Therefore, it can be said that the second bit rate can be set to a value smaller than the first bit rate also in this example.

FIG. 17 is a diagram showing a fourth example of a method of transmitting data (A) to (C) and data (D) (E) by the stylus 2. The stylus 2 according to this example uses either phase modulation (specifically, BPSK) or amplitude modulation as the modulation method (second modulation method) of the data (A) to (C), while the data (D). Amplitude phase modulation (specifically, 4QAM) is used as the modulation method (first modulation method) of (E). That is, different modulation methods are used for the data (A) to (C) and the data (D) (E), thereby comparing the bit rates of the data (A) to (C) with those of the data (D) (E). And make it smaller. The first modulation method is a modulation method having a smaller bit error rate than the second modulation method. Specifically, in the example of FIG. 17, the ratio of the bit rate (first bit rate) of the data (D) (E) to the bit rate (second bit rate) of the data (A) to (C) is 2: It is 1. Therefore, also in this example, it is realized that the second bit rate is set to a value smaller than the first bit rate.

FIG. 18 is a diagram showing a fifth example of a method of transmitting data (A) to (C) and data (D) (E) by the stylus 2. Similar to the stylus 2 according to the fourth example, the stylus 2 according to this example uses phase modulation (specifically, BPSK) as the modulation method for the data (A) to (C), while the data (D) (E). Quadrature phase modulation is used as the modulation method for. In the amplitude phase modulation according to this example, the first bit is represented by the phase (0 degree or 180 degrees), and the second bit is represented by the amplitude (1x or 2x). Also in this example, as in the fourth example, the ratio of the bit rate (first bit rate) of the data (D) (E) to the bit rate (second bit rate) of the data (A) to (C). Is 2: 1 so that the second bit rate can be set to a value smaller than the first bit rate.

FIG. 19 is a diagram showing a sixth example of a method of transmitting data (A) to (C) and data (D) (E) by the stylus 2. In this example, the command signal is transmitted by the sensor controller 31 and the downlink signal is transmitted by the stylus 2 during the blank period in which the display panel arranged together with the linear electrodes 30X and 30Y is not driven. 19 (a) shows the frame Frame_1 corresponding to the first blank period, and FIG. 19 (b) shows the frame corresponding to the second blank period following the first blank period. Frame_2 is shown respectively. The circled numbers 1 shown in each figure correspond to the data (B) and (C), and the circled numbers 2 correspond to the data (D) and (E).

When transmitting data (D) and (E), the stylus 2 according to this example transmits information for 14 bits using two frames Frame_1 and Frame_2. More specifically, in the frame Frame_1, 1-bit data data1 to data6 are provided following 2-bit information that serves as state information indicating whether the stylus 2 is in the hover state or the contact state. It is transmitted, and 1-bit data data7 to data14 are transmitted in the frame Frame_2. The 2-bit information as the first arranged state information in the frame Frame_1 is specifically "01" or "10", and the sensor controller 31 has data (D) (E) and data (B). ) It is arranged so as to be distinguishable from (C).

On the other hand, when transmitting the data (B) and (C), the stylus 2 transmits information for 2 bits using two frames Frame_1 and Frame_2. More specifically, in the frame Frame_1, the information of the first bit ("0" or "1") is transmitted eight times in a row, and in the frame Frame_1, the information of the second bit ("0" or "1") is transmitted. 1 ”) is transmitted eight times in a row.

That is, since the stylus 2 according to this example transmits each bit of the data to be transmitted only once in the data (D) and (E), it is repeatedly transmitted eight times in the data (B) and (C). Yes, this is the same as the stylus 2 according to the second example shown in FIG. 15, except that the number of repetitions is different. Therefore, also in this example, it is realized that the second bit rate is set to a value smaller than the first bit rate.

As described above, according to the stylus 2 according to the present embodiment, the bit rates (second bit rates) of the data (B) and (C) transmitted in the hover state are converted into the data transmitted in the contact state (second bit rate). D) It is realized that the value is smaller than the bit rate (first bit rate) of (E). Therefore, the noise immunity in the hover state where the S / N ratio of the downlink signal tends to deteriorate is improved, so that the undetected rate of the downlink signal is reduced, and the bit false detection rate during demodulation or decoding of the downlink signal is improved. The effect of reducing the decoding error rate after considering error correction is obtained, and as a result, even if the downlink signal is transmitted with the same transmission strength as the contact state, the downlink signal in the hover state It becomes possible to reduce the possibility of reception failure.

Further, since the data (A) is transmitted at the same small bit rate as the data (B) (C) regardless of the state of the stylus 2, the sensor controller 31 is in a state regardless of the state of the stylus 2. The information state can be reliably received. Therefore, since the reception operation of the sensor controller 31 (the first or second demodulation method described above) can be reliably changed according to the bit rate of the downlink signal, the data (B) is transmitted from the stylus 2 to the sensor controller 31. ) To (E) can be reliably transmitted.

Further, as shown in FIG. 10, since each frame has a frame number FN, when the stylus 2 divides large-sized data such as a unique ID and pen pressure data P into a plurality of frames and transmits the data. In addition, the sensor controller 31 on the receiving side can appropriately restore the information based on the frame number FN even if the divided information is not received in order.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and the present invention can be implemented in various embodiments without departing from the gist thereof. Of course.

For example, in the above embodiment, the burst signal and the data (A) are transmitted immediately before any of the data (B) to (E), but for example, the data (D) and (E) are described. , It is also possible to omit the transmission of the burst signal and the data (A) immediately before.

Further, in the above embodiment, the stylus 2 has been described as transmitting the state information State in all frames, but when two or more frames are continuously transmitted, the stylus 2 is set to the first frame among the two or more frames. The state information State may not be transmitted in the subsequent frames including the state information State. More specifically, the state information State may not be transmitted (transmission is omitted) in frames other than the frame to be transmitted first in the super frame. In this case, the sensor controller 31 may store the state information State received in the first frame and apply the state information State to the subsequent frames. It is preferable to omit the transmission of the state information State only when the stylus 2 is in the contact state.

Further, although not particularly mentioned in the above embodiment, the state of the stylus 2 when the contact state is determined in step S85 of FIG. 11 is referred to as "unique ID transmission mode", and the contact state is referred to in step S90 of FIG. The state of the stylus 2 when it is determined may be referred to as a "serial number transmission mode". In this case, the control unit 90 of the stylus 2 controls the transmission unit 75 to transmit the portion of the unique ID of the stylus 2 excluding the serial number according to the data (D) in the super frame corresponding to the unique ID transmission mode. In the super frame corresponding to the serial number transmission mode, the transmission unit 75 is controlled so as to transmit the serial number SN by the data (E).

Further, in the above embodiment, the stylus 2 determines the content of the command signal transmitted from the sensor controller 31, whereby the command is a transmission instruction (ID) of the unique ID and a transmission instruction of data other than the unique ID ( It is determined whether the stylus is DT), and depending on the result, it is switched between transmitting the unique ID and transmitting data other than the unique ID. In this determination, the stylus 2 is in its own state (for example, a switch). It may be performed according to the operating state of SW1). For example, when the switch SW1 is not operated (that is, when the user does not touch the operation unit of the stylus 2 (switch SW1, switch SW2, etc.) at all), the unique ID is transmitted and the switch SW1 is operated (that is, the switch SW1 is operated. That is, when it is ON), data other than the unique ID (such as information on the switch SW1) may be transmitted. By doing so, it is possible to complete the transmission of the unique ID having a relatively large amount of information in the non-operation state. Further, the unique ID transmitted in the hover state may include the information of the serial number SN transmitted in the contact state.

Further, when the sensor controller 31 transmits an uplink signal including arbitrary data (third digital value) such as a command, a checksum (second error detection code) corresponding to this data is added. May be good. In this case, it is preferable that the stylus 2 uses this checksum to determine whether or not the data transmitted by the sensor controller 31 can be correctly received, but the long burst signal, the burst signal, and the data (A) to (E). ) May be transmitted regardless of the result of this determination (even if the result of the determination is NG).

Hereinafter, the first and second modifications of the above embodiment will be described.

FIG. 20 is a diagram showing a configuration of a stylus 2 according to a first modification of the above embodiment. The sensor controller 31 and the stylus 2 according to the present modification are different from the above-described embodiment in that they use wireless communication that does not use the electrostatic coupling method for transmitting the uplink signal. It is also different from the above embodiment in that the stylus 2 supports transmission of two types of downlink signals DS1 and DS2 having different carrier signal formats. Both the downlink signals DS1 and DS2 are configured to be capable of transmitting the above-mentioned long burst signal, burst signal, and data (A) to (E), and the stylus 2 is a type of sensor controller 31 that is approaching. Use these properly according to your needs. Hereinafter, the configuration of the stylus 2 according to this modification will be described in detail with reference to FIG. 20.

As shown in FIG. 20, the stylus 2 according to this modification includes an electrode 21, a signal processing unit 24, a power supply 25, an amplification unit 26, and a reception unit 27.

The receiving unit 27 is a functional unit configured to be able to execute, for example, communication by Bluetooth (registered trademark) as wireless communication. In this modification, the sensor controller 31 receives the uplink signal transmitted by Bluetooth (registered trademark). To do.

The signal processing unit 24 is a functional unit having a function of selectively transmitting two types of downlink signals DS1 and DS2 and a function of receiving an uplink signal US via a receiving unit 27, specifically. , A control unit 91, a booster unit 92, an oscillation unit 93, and a switch unit 94.

The boosting unit 92 has a function of generating a DC voltage V1 by boosting the DC voltage supplied from the power supply 25. In a specific example, the booster 92 is configured by a DC-DC converter or a charge pump circuit.

The oscillating unit 93 has a function of generating an unmodulated sine wave signal (carrier signal) that vibrates at a predetermined frequency by performing an oscillating operation based on a DC voltage supplied from the power supply 25. The amplification unit 26 has a function of generating an unmodulated sine wave signal v2 by amplifying the sine wave signal generated by the oscillation unit 93 at a predetermined amplification factor. As shown in FIG. 20, the amplifier unit 26 is preferably configured by an amplifier circuit composed of a transformer and a capacitor.

The switch unit 94 is a switch element having one circuit and three contacts, and has a terminal a connected to the output end of the booster unit 92, a terminal b connected to the output end of the amplification unit 26, and a power supply wiring to which a ground potential is supplied. It is configured to have a terminal g connected to the electrode 21 and a common terminal c connected to the electrode 21.

The control unit 91 is an IC that supplies the control signal Ctrl for controlling the switch unit 94, controls the reception unit 27, and receives the uplink signal transmitted by the sensor controller 31, and is supplied from the power supply 25. It is configured to operate on power. In a specific example, the control unit 91 may be an ASIC or an MCU. The control unit 91 corresponds to the content of the uplink signal received via the reception unit 27 or the fact that the uplink signal is not received (the sensor controller 31 supports only one-way communication from the stylus 2 to the sensor controller 31). Case), the type of downlink signal (downlink signal DS1 or downlink signal DS2) used to transmit the long burst signal, burst signal, and data (A) to (E) shown in FIG. decide. Further, similarly to the control unit 90 shown in FIG. 8, the transmission / reception schedule of various signals and the like is determined, and the switch unit 94 is controlled based on the determined transmission / reception schedule.

The control unit 91 when transmitting the downlink signal DS1 controls the switch unit 94 so as to function as a first switch unit provided between the output end of the booster unit 92 and the electrode 21. That is, the process of switching the switch unit 94 is performed between the state in which the terminal a is connected to the common terminal c and the state in which the terminal g is connected to the common terminal c. The state where the terminal a is connected to the common terminal c corresponds to the state where the first switch unit is on, and the state where the terminal g is connected to the common terminal c corresponds to the state where the first switch unit is off. Corresponds to the state of being.

When a burst signal or a long burst signal is transmitted using the downlink signal DS1, the control unit 91 periodically performs switching control of the switch unit 94 at a predetermined cycle. When the terminal a is connected to the common terminal c, the DC voltage V1 becomes the output voltage of the switch unit 94. On the other hand, when the terminal g is connected to the common terminal c, the ground potential becomes the output voltage of the switch unit 94. Therefore, the switch unit 94 outputs an unmodulated pulse train signal, which becomes a long burst signal or a burst signal.

On the other hand, when a data signal is transmitted using the downlink signal DS1, the control unit 91 has data such as a unique ID, pressure data P, and switch information SW indicating on / off of a switch (not shown) provided in the stylus 2. By controlling the switching of the switch unit 94 in response to the above, a data signal which is a pulse train signal modulated based on the data is generated. As a specific method of modulation of the pulse train signal by the control unit 91, on-off modulation, frequency modulation, and the like can be considered.

The control unit 91 when transmitting the downlink signal DS2 controls the switch unit 94 so as to function as a second switch unit provided between the output end of the amplification unit 26 and the electrode 21. That is, the process of switching the switch unit 94 is performed between the state where the terminal b is connected to the common terminal c and the state where the terminal g is connected to the common terminal c. The state where the terminal b is connected to the common terminal c corresponds to the state where the second switch part is on, and the state where the terminal g is connected to the common terminal c means that the second switch part is off. Corresponds to the state of being.

When transmitting a burst signal or a long burst signal using the downlink signal DS2, the control unit 91 fixes the switch unit 94 on the terminal b side. Therefore, the unmodulated sine wave signal v2 is output from the switch unit 94, and this becomes a long burst signal or a burst signal.

On the other hand, when a data signal is transmitted using the downlink signal DS2, the control unit 91 performs data switching control of the switch unit 94 based on data such as a unique ID, pen pressure data P, and switch information SW. Generates a data signal, which is a sinusoidal signal modulated based on. On-off modulation is adopted as a specific method for modulating the sinusoidal signal by the control unit 91.

As described above, according to this modification, Bluetooth (registered trademark) can be used for transmitting and receiving uplink signals. Although an example of using Bluetooth (registered trademark) has been described here, it goes without saying that proximity wireless communication other than Bluetooth (registered trademark) may be used for transmitting and receiving uplink signals.

Further, according to this modification, the stylus 2 can perform bidirectional or unidirectional communication with a plurality of different types of sensor controllers 31 by properly using the downlink signals DS1 and DS2. ..

FIG. 21 is a processing flow diagram showing the operation of the stylus 2 according to the second modification of the above embodiment. The stylus 2 according to this modification is different from the above embodiment in that it determines its own state based on the reception intensity of the uplink signal instead of the pen pressure detected by the pen pressure detection sensor 23. Hereinafter, the operation of the stylus 2 according to this modification will be described in detail with reference to FIG. 21, focusing on the differences from the above embodiment.

The stylus 2 according to this modification performs the determination of steps S100 and S101, respectively, instead of the determination of steps S85 and S92 shown in FIG. Both steps S100 and S101 are steps for determining the reception strength of the command signal detected in the immediately preceding step S80.

When it is determined in step S100 that the reception intensity is less than a predetermined value (that is, "weak"), the stylus 2 determines its own state as the hover state. Then, the burst signal and the data (A) and (B) are transmitted as in the case where the hover state is determined in step S85 (steps S86 to S88). On the other hand, when it is determined in step S100 that the reception intensity is equal to or higher than a predetermined value (that is, “strong”), the stylus 2 determines its own state as the contact state. Then, the burst signal and the data (A) and (D) are transmitted as in the case where the contact state is determined in step S85 (steps S89 to S91).

Further, when it is determined in step S101 that the reception intensity is less than a predetermined value (that is, "weak"), the stylus 2 determines its own state as the hover state. Then, the burst signal and the data (A) and (C) are transmitted as in the case where the hover state is determined in step S92 (steps S93 to S95). On the other hand, when it is determined in step S101 that the reception intensity is equal to or higher than a predetermined value (that is, “strong”), the stylus 2 determines its own state as the contact state. Then, the burst signal and the data (A) and (E) are transmitted as in the case where the contact state is determined in step S92 (steps S97 to S99).

As described above, according to the stylus 2 according to the present modification, the state of the stylus 2 can be determined based on the reception strength of the command signal regardless of the writing pressure. Therefore, for example, the present invention can be applied to a stylus 2 that does not have a pen pressure detection function.

In this modification, the stylus 2 determines its own state based on the reception strength of the uplink signal (specifically, the command signal). However, the reception strength of the downlink signal in the sensor controller 31 is used. Based on this, it is also possible to configure the sensor controller 31 to determine the state of the stylus 2 and notify the stylus 2 of the result. In this case, the sensor controller 31 includes the state information indicating the state of the stylus 2 in a part of the command signal, and the stylus 2 acquires its own state by receiving and decoding this state information. Is preferable.

2 Stylus 3 Electronic equipment 20 Core 21 Electrode 22,44x, 44y, 62 Switch 23 Pen pressure detection sensor 24 Signal processing unit 25 Power supply 26 Amplification unit 27, 50, 71 Receiver 30 Sensor 30X, 30Y Linear electrode 31 Sensor controller 40 Selection unit 41x, 41y Conductor selection circuit 51 Amplifier circuit 52 Detection circuit 53 Converter 60, 75 Transmission unit 61 Pattern supply unit 63 Diffusion processing unit 64 Code string holding unit 65 Transmission guard unit 70 Logic unit 71a Correlation reproduction unit 71b Correlation calculation Instrument 73 Modulation unit 74 Booster circuit 76 Switching unit 90, 91 Control unit 92 Booster unit 93 Oscillating unit 94 Switch unit FN Frame number Mode Mode information Op Inversion bit P Pen pressure data RS Reservation information SN Serial number Start Start flag State Status information SW , SW1, SW2 Switch information

Claims (5)

A sensor controller that is connected to a group of electrodes arranged on a panel and detects the position of a stylus using an electric charge induced in the group of electrodes.
Determining whether the stylus is in the undetected state or the detected state,
In the undetected state, a first command signal is transmitted to the stylus using the electrode group provided on the panel.
In the detected state, a second command signal different from the first command signal is transmitted by using a number of electrodes smaller than the number of the electrode group.
The position of the stylus is derived based on the downlink signal transmitted from the stylus that detected the first command signal or the second command signal .
Sensor controller. The first command signal is a signal indicating a transmission instruction of a long burst signal.
The second command signal is a signal indicating a data transmission instruction.
The sensor controller according to claim 1. A small number of electrodes compared to the number of the electrode group are electrodes in the vicinity of the position of the stylus.
The sensor controller according to claim 1 or 2 . With a stylus
A system including a sensor controller connected to a group of electrodes arranged on a panel and detecting the position of the stylus using an electric charge induced in the group of electrodes.
The sensor controller is
Determining whether the stylus is in the undetected state or the detected state,
In the undetected state, a first command signal is transmitted to the stylus using the electrode group provided on the panel.
In the detected state, a second command signal different from the first command signal is transmitted by using a number of electrodes smaller than the number of the electrode group.
The position of the stylus is derived based on the downlink signal transmitted from the stylus that detected the first command signal or the second command signal.
system. With a stylus
A method performed in a system including a sensor controller connected to a group of electrodes arranged on a panel and detecting the position of the stylus using an electric charge induced in the group of electrodes.
A step in which the sensor controller determines whether the stylus is in an undetected state or a detected state.
When the sensor controller is in the undetected state, a step of transmitting a first command signal to the stylus using the electrode group provided on the panel, and
When the sensor controller is in the detected state, a step of transmitting a second command signal different from the first command signal by using a number of electrodes smaller than the number of the electrode group, and
A step in which the sensor controller derives the position of the stylus based on a downlink signal transmitted from the stylus that has detected the first command signal or the second command signal.
How to include.

Images