Stylus pen and integrated circuit

Abstract

A stylus and an integrated circuit capable of inhibiting a fluctuation in a reference potential caused by a signal induced in a human body as a cause, resulting in a signal induced in an electrode being temporarily undetectable are provided. The stylus (16) includes a housing (42) serving as a reference potential, a first electrode (32), a second electrode (34), a first reception circuit (50) grounded to the housing (42) and receiving a transmission signal (US1) transmitted from an electronic device (14) via electrostatic coupling formed between the first electrode (32) and a sensor electrode group (18), and a second reception circuit (52) grounded to the housing (42) and receiving a transmission signal (US2) transmitted from the electronic device (14) via electrostatic coupling formed between the second electrode (34) and the sensor electrode group (18).

Description

Technical Field

[0001] The present invention relates to a stylus pen used with an electronic device including a capacitive touch sensor including a group of sensor electrodes arranged in a planar shape, and an integrated circuit used in the stylus pen. Background Art

[0002] Conventionally, there are known position detection systems consisting of an active stylus (hereinafter referred to as a "stylus"), a position indicator with a built-in power source, and an electronic device equipped with a touch sensor. In such systems, signals are transmitted and received between the stylus and the electronic device to exchange data or synchronize control. Hereinafter, to distinguish between the two types of signals, the signal from the electronic device is referred to as the "uplink signal," and the signal from the stylus is referred to as the "downlink signal."

[0003] The stylus receives an uplink signal through electrostatic coupling between the electrodes at the tip of the stylus and the sensor electrode group that forms part of the touch sensor. The uplink signal is then converted into a digital signal by a receiving circuit, thereby acquiring data supplied by the electronic device. For example, contact between a user's body and the touch surface of an electronic device can sometimes create electrostatic coupling between the user's body and the sensor electrode group. The uplink signal induced in the body can act by causing a change in the body's electrical potential.

[0004] That is, under the assumption that [1] the reference potential of the stylus is set to the potential of the housing, [2] the user is holding the stylus, and [3] the uplink signal is sensed by the stylus electrodes, and [4] the uplink signal can be sensed at the contact part of the human body, and [5] the relative position and posture relationship between the stylus electrodes and the contact part of the human body satisfies specific conditions, fluctuations in the reference potential that hinder the detection of the uplink signal may appear at the ground terminal of the stylus receiving circuit. As a result, the uplink signal sensed at the stylus electrodes may be temporarily undetectable due to the fluctuations in the reference potential.

[0005] Figure 18 Schematically shows a state where an uplink signal cannot be detected temporarily. Figure 18 (a) shows the structure of the receiving circuit 1, Figure 18 (b) shows Figure 18 (a) Temporal changes in the signal levels measured at nodes 4 and 5.

[0006] For example, Figure 18 As shown in (a), it is assumed that the input terminal of the receiving circuit 1 is connected to the electrode 2 and the ground terminal of the receiving circuit 1 is grounded and connected to the housing 3. Figure 18As can be seen in Figure (b), the GND potential at node 5 maintains a roughly constant signal level when the human body is not in contact with the touch surface (during reception of bits 1 and 2). However, when the human body is in contact with the touch surface (during reception of bits 3 and 4), the GND potential at node 5 fluctuates according to the waveform of the uplink signal at node 4. As a result, the reception of bit 3 is not performed correctly, and the uplink signal cannot be detected.

[0007] Therefore, Patent Document 1 discloses a sensor controller that controls the driving of a sensor electrode group by transmitting a cancel signal for suppressing the uplink signal from appearing at the ground terminal of a receiving circuit of a stylus pen together with the uplink signal.

[0008] Prior art literature

[0009] Patent Literature

[0010] Patent Document 1: Japanese Patent Application Publication No. 2019-091442 Summary of the Invention

[0011] Problems to be solved by the invention

[0012] However, Patent Document 1 only discloses the operation of the electronic device for solving the above-mentioned problem, and does not consider any solution on the stylus pen side.

[0013] An object of the present invention is to provide a stylus pen and an integrated circuit that can suppress the temporary undetectability of signals induced in electrodes due to fluctuations in a reference potential caused by signals induced in the human body.

[0014] Means for solving problems

[0015] The first touch pen of the present invention is used together with an electronic device having an electrostatic capacitance touch sensor including a sensor electrode group arranged in a planar shape, and comprises: a shell used as a reference potential; a first electrode; a second electrode different from the first electrode; a first receiving circuit connected to the shell ground and receiving a transmission signal sent from the electronic device via an electrostatic coupling formed between the first electrode and the sensor electrode group; a second receiving circuit connected to the shell ground and receiving a transmission signal sent from the electronic device via an electrostatic coupling formed between the second electrode and the sensor electrode group; and a control circuit for performing reception control on the first receiving circuit and the second receiving circuit.

[0016] The integrated circuit in the second present invention is a circuit used in a stylus pen, wherein the stylus pen has a shell used as a reference potential, a first electrode and a second electrode different from the first electrode, and is used together with an electronic device having an electrostatic capacitance touch sensor including a sensor electrode group arranged in a planar shape, and the integrated circuit has: a first receiving circuit connected to the shell ground and receiving a transmission signal sent from the electronic device via an electrostatic coupling formed between the first electrode and the sensor electrode group; a second receiving circuit connected to the shell ground and receiving a transmission signal sent from the electronic device via an electrostatic coupling formed between the second electrode and the sensor electrode group; and a control circuit for performing reception control on the first receiving circuit and the second receiving circuit.

[0017] For example, when a user's body contacts the touch surface of an electronic device, electrostatic coupling may occur between the body and the sensor electrode group, causing a signal transmitted from the electronic device to be sensed at the contact site. Therefore, a first receiving circuit for receiving the signal induced at the first electrode and a second receiving circuit for receiving the signal induced at the second electrode are provided, respectively, so that the signal is input from the first and second electrodes, which have different relative positions and postures with respect to the contact site.

[0018] Furthermore, by connecting the first and second receiving circuits to a common housing ground, which serves as a reference potential, the effects of fluctuations in the reference potential caused by signals induced by the human body on the respective receiving circuits can be spatially and temporally offset. This increases the likelihood that even if one receiving circuit temporarily and suddenly fails to function due to the delicate balance between the stylus electrode and the human body, the other receiving circuit will function as intended. This prevents temporary undetectability of signals induced at the electrodes due to fluctuations in the reference potential.

[0019] The third present invention is a touch pen used together with an electronic device having an electrostatic capacitance touch sensor including a surface-arranged sensor electrode group, and comprising: a shell used as a reference potential; a first electrode; a second electrode different from the first electrode; a receiving circuit that receives transmission signals sent from the electronic device via electrostatic coupling formed between the first electrode and the sensor electrode group and between the second electrode and the sensor electrode group, and is constructed to include a first amplifier circuit and a second amplifier circuit independent of the first amplifier circuit, the first amplifier circuit being grounded to the shell and amplifying the signal induced at the first electrode, and the second amplifier circuit being grounded to the shell and amplifying the signal induced at the second electrode; and a control circuit that performs reception control on the receiving circuit.

[0020] The integrated circuit in the fourth present invention is a circuit used in a stylus pen, wherein the stylus pen has a shell used as a reference potential, a first electrode and a second electrode different from the first electrode, and is used together with an electronic device having an electrostatic capacitance touch sensor including a sensor electrode group arranged in a planar shape, the integrated circuit having: a receiving circuit, which receives transmission signals sent from the electronic device via electrostatic coupling formed between the first electrode and the sensor electrode group and between the second electrode and the sensor electrode group, respectively, and is constructed to include a first amplifier circuit and a second amplifier circuit independent of the first amplifier circuit, the first amplifier circuit is grounded to the shell and amplifies the signal induced at the first electrode, and the second amplifier circuit is grounded to the shell and amplifies the signal induced at the second electrode; and a control circuit, which performs reception control on the receiving circuit.

[0021] For example, when a user's body contacts the touch surface of an electronic device, electrostatic coupling may occur between the body and the sensor electrode group, causing a signal transmitted from the electronic device to be sensed at the contact site. Therefore, a first amplifier circuit for amplifying the signal sensed at the first electrode and a second amplifier circuit for amplifying the signal sensed at the second electrode are each provided within the receiving circuit, so that the transmitted signal is input from first and second electrodes having different relative positions and postures relative to the contact site.

[0022] Furthermore, by connecting the first and second amplifier circuits to a common housing ground, which serves as a reference potential, the effects of fluctuations in the reference potential caused by signals induced by the human body on each amplifier circuit can be spatially and temporally offset. This increases the likelihood that even if one amplifier circuit temporarily and suddenly fails to function due to the delicate balance between the stylus electrode and the human body, the other amplifier circuit will function as intended. This prevents temporary undetectability of signals induced at the electrodes due to fluctuations in the reference potential.

[0023] Effects of the Invention

[0024] According to the present invention, it is possible to suppress temporary undetectability of signals induced in electrodes due to fluctuations in the reference potential caused by signals induced in the human body. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 FIG. 1 is an overall configuration diagram of a position detection system incorporating the stylus pen according to the first embodiment of the present invention.

[0026] Figure 2 yes Figure 1 Schematic diagram of the electronic device and stylus shown.

[0027] Figure 3 FIG. 1 is a diagram schematically showing the detection result of the uplink signal corresponding to the position of the stylus pen.

[0028] Figure 4 It is schematically shown Figure 1 and Figure 2 Diagram of the internal structure of the stylus.

[0029] Figure 5 yes Figure 4 The block diagram of the circuit board is shown.

[0030] Figure 6 It shows Figure 5 FIG. 1 is a diagram showing a specific structure of a first receiving circuit.

[0031] Figure 7 It shows Figure 5 FIG. 1 is a diagram showing a specific structure of a second receiving circuit.

[0032] Figure 8 It shows Figure 1 and Figure 2 A diagram showing an example of a circuit structure in a touch IC.

[0033] Figure 9 It is a diagram showing an example of an uplink signal.

[0034] Figure 10 It is a diagram schematically showing the effects of the first embodiment.

[0035] Figure 11 It is a diagram schematically showing the effects of the first embodiment.

[0036] Figure 12 This is a block diagram of a circuit board included in the stylus pen according to the second embodiment of the present invention.

[0037] Figure 13 This is a diagram showing a first example of the specific structure of the first and second receiving systems.

[0038] Figure 14 This is a diagram showing a first example of a specific configuration of a processing circuit.

[0039] Figure 15 This is a diagram showing a second example of the specific structure of the first and second receiving systems.

[0040] Figure 16 This is a diagram showing a second example of the specific configuration of the processing circuit.

[0041] Figure 17 This is a diagram showing another configuration example related to the connection between electrodes and a receiving circuit.

[0042] Figure 18 It is a diagram schematically showing a state in which an uplink signal cannot be detected temporarily. DETAILED DESCRIPTION

[0043] [First embodiment]

[0044] First, refer to Figures 1 to 11 Next, the stylus pen and the integrated circuit according to the first embodiment of the present invention will be described.

[0045] <Overall Structure of Position Detection System 10>

[0046] Figure 1 This is a diagram showing the overall structure of a position detection system 10 incorporating a stylus pen 16 according to a first embodiment of the present invention. Position detection system 10 is basically composed of an electronic device 14 having a touch detection surface (hereinafter referred to as touch surface 12) and a stylus pen 16 used with the electronic device 14.

[0047] The electronic device 14 is constituted by, for example, a tablet terminal, a smartphone, or a personal computer. The user can write pictures or text on the electronic device 14 by holding the stylus pen 16 with one hand and moving the stylus pen 16 while pressing the pen tip against the touch surface 12 .

[0048] The stylus 16 is a pen-shaped pointing device capable of bidirectional communication with the electronic device 14. Hereinafter, the signal sent by the electronic device 14 to the stylus 16 is referred to as the "uplink signal US," and the signal sent by the stylus 16 to the electronic device 14 is referred to as the "downlink signal DS." It should be noted that the stylus 16 is an "active" electronic pen that actively generates a signal using its own stored electrical energy and transmits this signal as the downlink signal DS to the electronic device 14.

[0049] Figure 2 yes Figure 1 Schematic diagram of electronic device 14 and stylus 16. The electronic device 14 includes a touch sensor 20, a touch IC (Integrated Circuit) 22, a host processor 24, and a display panel 26.

[0050] The touch sensor 20 is an electrostatic capacitance type sensor that is overlapped on the display panel 26. The touch sensor 20 can be a mutual capacitance type sensor or a self-capacitance type sensor. The touch sensor 20 is configured to include a sensor electrode group 18 that is separated from each other and arranged in a planar shape along the arrangement direction. The material of the sensor electrode can be indium tin oxide (ITO) or a metal such as copper, silver, or gold. In the example of this figure, the touch sensor 20 is an "external type" sensor installed from the outside to the display panel 26, but it can also be replaced by a "built-in type" (if further classified, it can be an On-Cell type or In-Cell type) sensor that is integrally formed with the display panel 26.

[0051] The touch IC 22 is an integrated circuit that controls the drive of the touch sensor 20. The touch IC 22 drives the touch sensor 20 based on a control signal supplied from the host processor 24. This allows the touch IC 22 to perform a "pen detection function" that detects the state of the stylus pen 16 and a "touch detection function" that detects touch by a user's finger or the like.

[0052] The host processor 24 is composed of a processing and arithmetic device including a CPU (Central Processing Unit), an MPU (Micro-Processing Unit), and a GPU (Graphics Processing Unit). By reading and executing programs stored in a memory (not shown), the host processor 24 can perform various functions, including the generation and rendering of digital ink, the creation of image signals, and the control of data transmission and reception.

[0053] The display panel 26 is composed of, for example, a liquid crystal panel, an organic EL (Electro Luminescence) panel, or electronic paper. The display panel 26 drives a plurality of pixels by applying a driving voltage to signal lines arranged in a matrix in the row and column directions, thereby displaying an image or video in the display area.

[0054] <Problem>

[0055] Figure 2 This is an equivalent circuit diagram when the user's human body BD is in contact with the touch surface 12 of the electronic device 14. The following assumes that [1] the reference potential of the stylus pen 16 (hereinafter also referred to as "GND potential") is set to the potential of the housing, [2] the user is holding the stylus pen 16, and [3] the uplink signal US is sensed by the electrodes of the stylus pen 16.

[0056] Electronic device 14, stylus 16, and human body BD are electrically connected to each other via electrostatic coupling. Stylus 16 is electrically connected to sensor electrode group 18 via capacitance C1 formed at position P directly below the electrode of the stylus tip. Human body BD is grounded via capacitance C3 generated between the GND potential of stylus 16 and the ground. Touch IC 22 and display panel 26 are commonly grounded via capacitance C4 generated between the GND potential of electronic device 14 and the ground.

[0057] The ground terminal of the receiving circuit of the stylus 16 is connected to the earth via the housing and the human body BD. This allows the receiving circuit to perform its intended actions and detect the uplink signal US from the input terminal. However, when the human body BD (for example, a portion of the hand holding the stylus 16) contacts the touch surface 12 of the electronic device 14, the human body BD may be electrically connected to the sensor electrode group 18 via the electrostatic capacitance C5 formed at position Q on the touch surface 12. In other words, the uplink signal US induced in the human body BD may act in a manner that causes the potential of the human body BD to change.

[0058] When the relative position and posture relationship between the electrode of stylus pen 16 and the contact point of human body BD satisfies specific conditions, fluctuations in the GND potential that hinder detection of the uplink signal US may occur at the ground terminal of the receiving circuit of stylus pen 16. As a result, the uplink signal US received via the electrode of stylus pen 16 may become temporarily undetectable due to the aforementioned fluctuations in the GND potential.

[0059] Figure 3 This diagram schematically illustrates the detection results of the uplink signal US corresponding to the position of stylus 16. Here, assume that the user, with the palm of their left hand in contact with touch surface 12, moves stylus 16 along the trajectories T1 and T2 around their left hand while holding it with their right hand. Only when bidirectional communication is possible between electronic device 14 and stylus 16 can electronic device 14 track the indicated position of stylus 16 and display the stroke (the trajectory of the indicated position). Specifically, note that if the receiving circuit of stylus 16 can consistently detect uplink signal US, a single stroke is drawn uninterruptedly.

[0060] Stylus 16 uses three electrodes: "A," "B," and "A+B" to receive uplink signals US. "A" is the tip electrode located at the tip of stylus 16, and "B" is the ring electrode located further back than the tip. It should be noted that "A+B" corresponds to an integrated electrode formed by electrically connecting the tip and ring electrodes described above. For ease of illustration, the depiction of the paths of the three electrodes is staggered in the vertical direction (for trajectory T1) or the horizontal direction (for trajectory T2).

[0061] As can be understood from this figure, the three types of drawing results show similar tendencies for line breaks (areas surrounded by dotted lines), but there is little regularity in the position and length of the breaks. This is because the activation conditions related to the aforementioned relative position and posture relationship are limited, and the uplink signal US can be locally and suddenly undetected due to the delicate balance between the contact area between the stylus pen 16 electrode and the human body BD.

[0062] Hereinafter, a method for suppressing temporary undetectability of the uplink signal US induced in the electrode due to fluctuations in the GND potential caused by a signal induced in the human body BD, using only the device configuration on the stylus pen 16 side, will be described.

[0063] <Structure of Stylus Pen 16>

[0064] Figure 4 It is schematically shown Figure 1 and Figure 2 FIG1 is a diagram showing the internal structure of the stylus pen 16. The stylus pen 16 includes a core 30, a tip electrode 32 (first electrode), a ring electrode 34 (second electrode), a writing pressure detection sensor 36, a circuit board 38 (integrated circuit), and a battery 40.

[0065] Core 30 is a rod-shaped member arranged along the shaft of stylus pen 16. Tip electrode 32 and ring electrode 34 are electrodes made of or containing a conductive material such as metal. Specifically, tip electrode 32 is a conical electrode attached to the tip of core 30. Ring electrode 34 is a tapered ring-shaped electrode with a diameter that gradually decreases toward the tip.

[0066] As from Figure 4 As understood, the tip electrode 32 and the ring electrode 34 [1] are provided at the pen tip (end side of the housing 42), [2] have different shapes, [3] have the same axial directions, [4] are rotationally symmetrical with respect to the pen axis, and [5] are arranged in a manner separated in the pen axis direction. It should be noted that the shape and arrangement of the tip electrode 32 and the ring electrode 34 are not limited to Figure 4 The examples may be modified as needed.

[0067] The pen pressure detection sensor 36 is physically connected to the core 30 and is configured to detect the pen pressure applied to the tip of the core 30. For example, a variable capacitance capacitor whose capacitance changes according to the pen pressure is used as the pen pressure detection sensor 36. The circuit board 38 is a substrate that forms the circuitry for operating the stylus 16. The battery 40 is a power source that supplies driving power to the electronic components and elements provided on the circuit board 38.

[0068] Furthermore, stylus pen 16 includes a housing 42 that houses the aforementioned components. The cylindrical housing 42 is made of, or contains, a conductive material such as metal. When using stylus pen 16, the user grasps stylus pen 16 while contacting the outer circumference of housing 42. This electrically connects human body BD to stylus pen 16 via the capacitance formed at the contact point of housing 42.

[0069] Figure 5 It shows Figure 4 38 is a block diagram of a circuit board 38. The circuit board 38 is provided with a microcontroller unit (hereinafter referred to as MCU44; control circuit), a first switch 46, a second switch 48, a first receiving circuit 50, a second receiving circuit 52 and a transmitting circuit 54.

[0070] The MCU 44 is a unit that performs overall control over various components of the stylus 16. The MCU 44 is configured to receive uplink signals US1 and US2 from the electronic device 14 by performing desired reception control on the first receiving circuit 50 and the second receiving circuit 52. Furthermore, the MCU 44 is configured to transmit downlink signals DS to the electronic device 14 by performing desired transmission control on the transmitting circuit 54.

[0071] The first switch 46 is a switching element configured to connect a common terminal to either an R terminal or a T terminal. The common terminal of the first switch 46 is connected to the tip electrode 32, the R terminal is connected to the input of the first receiving circuit 50, and the T terminal is connected to the output of the transmitting circuit 54. The MCU 44 controls the switching of the first switch 46 to selectively receive the uplink signal US1 and transmit the downlink signal DS.

[0072] The second switch 48 is a switching element configured to connect a common terminal to either an R terminal or a T terminal. The common terminal of the second switch 48 is connected to the annular electrode 34, the R terminal is connected to the input terminal of the second receiving circuit 52, and the T terminal is connected to the output terminal of the transmitting circuit 54. The MCU 44 controls the switching of the second switch 48 to selectively receive the uplink signal US2 and transmit the downlink signal DS.

[0073] The first receiving circuit 50 demodulates the uplink signal US1 sensed by the tip electrode 32 and outputs the demodulated data (hereinafter referred to as first data DAT1) to the MCU 44. The ground terminal of the first receiving circuit 50 is grounded to the housing 42 of the stylus pen 16.

[0074] The second receiving circuit 52 demodulates the uplink signal US2 sensed by the annular electrode 34 and outputs the demodulated data (hereinafter referred to as second data DAT2) to the MCU 44. The ground terminal of the second receiving circuit 52 is grounded to the housing 42 of the stylus pen 16.

[0075] The MCU 44 processes at least one of the first data DAT1 and the second data DAT2 to obtain control data from the electronic device 14. For example, the MCU 44 may process the first data DAT1 while it can obtain the first data DAT1 from the first receiving circuit 50. On the other hand, the MCU 44 may process the second data DAT2 obtained from the second receiving circuit 52 while it cannot obtain the first data DAT1 from the first receiving circuit 50.

[0076] The transmission circuit 54 generates a downlink signal DS under the control of the MCU 44. When the downlink signal DS is a "position signal," the transmission circuit 54 outputs an unmodulated carrier signal. When the downlink signal DS is a "data signal," the transmission circuit 54 modulates the carrier signal with transmission data and outputs the modulated carrier signal.

[0077] Figure 6 It shows Figure 5 FIG. 5 is a diagram showing a specific structure of the first receiving circuit 50 . Figure 7 It shows Figure 5 The specific structure of the second receiving circuit 52 is shown in FIG. Figure 6 and Figure 7 As can be understood, in this embodiment, the second receiving circuit 52 has the same structure as the first receiving circuit 50 .

[0078] like Figure 6 As shown, the first receiving circuit 50 is composed of an analog circuit 60a and a digital circuit 62a (first detection circuit) connected in series. The analog circuit 60a includes an amplifier circuit 66a (first amplifier circuit) and a ΔΣ type AD converter circuit (hereinafter referred to as ΔΣ type ADC 68a). The digital circuit 62a includes a matched filter 70a and a data recovery unit 72a.

[0079] like Figure 7 As shown, the second receiving circuit 52 is composed of an analog circuit 60b and a digital circuit 62b (second detection circuit) connected in series. The analog circuit 60b is configured to include an amplifier circuit 66b (second amplifier circuit) and a ΔΣ ADC 68b. The digital circuit 62b is configured to include a matched filter 70b and a data recovery unit 72b.

[0080] The amplifier circuit 66a is a circuit for amplifying the uplink signal US1 sensed at the tip electrode 32, and its input end is connected to the R terminal of the first switch 46, and its ground end is connected to the housing 42. The amplifier circuit 66b is a circuit for amplifying the uplink signal US2 sensed at the ring electrode 34, and its input end is connected to the R terminal of the second switch 48, and its ground end is connected to the housing 42. The amplification factor of the amplifier circuit 66a is preferably equal to the amplification factor of the amplifier circuit 66b, but may be different from the amplification factor of the amplifier circuit 66b. It should be noted that in Figure 6 In the example shown, the amplifier circuit 66a is directly connected to the housing 42, but may be indirectly connected to the housing 42 via a conductive member (not shown). Figure 7 The same applies to the amplifier circuit 66b.

[0081] The ΔΣ ADC 68a performs ΔΣ AD conversion on the output signal AO1 of the amplifier circuit 66a to output a binary, ternary, or multi-valued signal. The ΔΣ ADC 68b performs ΔΣ AD conversion on the output signal AO2 of the amplifier circuit 66b to output a binary, ternary, or multi-valued signal. It should be noted that the term "ΔΣ" refers to an AD conversion method that converts the difference (Δ) between the sampled voltage and the output voltage into a pulse train by integrating (Σ) the difference (Δ) between the sampled voltage and the output voltage using an integrator and comparing the resulting integrated value with a reference voltage.

[0082] Matched filter 70a detects the data signal corresponding to uplink signal US1 by performing a correlation operation between output signal CO1 of ΔΣ ADC 68a and comparison pattern PTc read from storage circuit 74. Matched filter 70b detects the data signal corresponding to uplink signal US2 by performing a correlation operation between output signal CO2 of ΔΣ ADC 68b and comparison pattern PTc read from storage circuit 74. Here, "correlation operation" refers to calculating the correlation value between the sequentially supplied chip string and the known comparison pattern PTc (here, the sequence of spreading codes corresponding to uplink signal US) and detecting and outputting the bit when the correlation value shows a peak.

[0083] The data restoration unit 72a restores the data signal detected by the matched filter 70a according to a known rule and outputs the first data DAT1. The data restoration unit 72b restores the data signal detected by the matched filter 70b according to a known rule and outputs the second data DAT2.

[0084] The storage circuit 74 is related to the touch IC 22 ( Figure 8 ) Multiple spreading codes that may be used in transmitting the uplink signal US are stored as comparison patterns PTc, respectively, with the patterns representing the original waveforms (here, binary patterns of 0 / 1).

[0085] Thus, the first receiving circuit 50 includes a digital circuit 62a (first detection circuit) that detects the first data DAT1 represented by the uplink signal US by performing a correlation operation between the output signal CO1 (first processed signal) obtained by processing the output signal AO1 (first amplified signal) of the amplifier circuit 66a and the comparison pattern PTc corresponding to the uplink signal US. Furthermore, the second receiving circuit 52 includes a digital circuit 62b (second detection circuit) that detects the second data DAT2 represented by the uplink signal US by performing a correlation operation between the output signal CO2 (second processed signal) obtained by processing the output signal AO2 (second amplified signal) of the amplifier circuit 66b and the comparison pattern PTc corresponding to the uplink signal US. In this case, the MCU 44 can obtain the first data DAT1 from the first receiving circuit 50 and the second data DAT2 from the second receiving circuit 52.

[0086] It should be noted that, instead of this, the digital circuit 62a may perform correlation calculation between the output signal AO1 of the amplifier circuit 66a and the comparison pattern PTc, and the digital circuit 62b may perform correlation calculation between the output signal AO2 of the amplifier circuit 66b and the comparison pattern PTc.

[0087] <Structure of Touch IC 22>

[0088] Figure 8 It shows Figure 1 and Figure 2 FIG. 2 is a diagram showing an example of a circuit structure in a touch IC 22. The touch IC 22 is connected to the sensor electrode group 18 ( Figure 2 ), and is composed of an MCU221, a logic unit 222, a receiving unit 223, a sending unit 224 and a selecting unit 225.

[0089] Sensor electrode group 18 includes multiple sensor electrodes 18X for detecting position in the X direction (X coordinate) and multiple sensor electrodes 18Y for detecting position in the Y direction (Y coordinate). Sensor electrodes 18X and 18Y are insulated by being sandwiched between insulating substrates (not shown) made of glass or resin. Multiple sensor electrodes 18X extend in the Y direction and are spaced apart from each other at equal intervals along the X direction. Multiple sensor electrodes 18Y extend in the X direction and are spaced apart from each other at equal intervals along the Y direction.

[0090] The MCU 221 and the logic unit 222 control the touch IC 22's transmission and reception operations by controlling the receiving unit 223, the transmitting unit 224, and the selecting unit 225. The MCU 221 is a control unit that reads programs from its own memory and executes them. Furthermore, the logic unit 222 generates control signals for the receiving unit 223, the transmitting unit 224, and the selecting unit 225 based on the control of the MCU 221.

[0091] MCU 221 selectively controls reception of downlink signals DS from stylus pen 16 and transmission of uplink signals US to stylus pen 16 . When transmitting uplink signals US, MCU 221 generates a command cmd for stylus pen 16 and supplies the command cmd to transmitter 224 .

[0092] The receiving unit 223 has a function of receiving the downlink signal DS transmitted by the stylus pen 16 based on the control signal supplied from the logic unit 222. Specifically, the receiving unit 223 decodes the signal supplied from the selecting unit 225 and supplies the obtained digital signal to the MCU 221 as a received signal.

[0093] Furthermore, when the downlink signal DS is a "position signal" indicating the position of the stylus 16, the MCU 221 calculates the position coordinates (x, y) of the stylus 16 on the touch surface 12 based on the reception intensity at each of the plurality of sensor electrodes 18X and 18Y, and outputs the calculated values ​​to the host processor 24. On the other hand, when the downlink signal DS is a "data signal" including transmission data, the MCU 221 obtains the response data Res (specifically, the unique ID, pen pressure, pen switch on / off information, etc.) contained in the data signal and outputs the calculated values ​​to the host processor 24.

[0094] The transmission unit 224 has a function of generating an uplink signal US under the control of the MCU 221 and the logic unit 222. Specifically, the transmission unit 224 includes a code string holding unit 224a and a spread spectrum processing unit 224b.

[0095] The code string storage unit 224a has the function of generating and storing a spectrum spreading code (hereinafter also referred to as a "spreading code") having an autocorrelation characteristic based on a control signal supplied from the logic unit 222. The code string storage unit 224a is configured to generate and store a different spreading code for each content of the transmission data ("P", "0000", "0001", etc.).

[0096] The spread spectrum processing unit 224b has a function of generating a desired AC signal (eg, a pulse signal, a triangular wave signal, a sine wave signal, etc.) based on the command cmd supplied from the MCU 221. Figure 9As shown, first, the spread spectrum processing unit 224b generates an uplink signal US according to the input command cmd. In the example of this figure, the uplink signal US consists of two preamble codes "P", 1-byte data "D1, D2, D3" and an error detection signal "CRC".

[0097] The spreading processing unit 224b then replaces each of the plurality of transmission data constituting the uplink signal US with the spreading code held by the code string holding unit 224a and generates a binary chip string by performing Manchester encoding. The spreading processing unit 224b then generates a pulse signal corresponding to the chip string.

[0098] return Figure 8 The selection unit 225 is connected to the sensor electrode group 18 and performs a switching operation according to a control signal from the logic unit 222. Specifically, the selection unit 225 includes two switches 226x and 226y and two electrode selection circuits 227x and 227y.

[0099] Switches 226x and 226y are switching elements each configured to connect a common terminal to either a T terminal or an R terminal. The common terminal of switch 226x is connected to electrode selection circuit 227x, the T terminal is connected to the output of transmitter 224, and the R terminal is connected to the input of receiver 223. The common terminal of switch 226y is connected to electrode selection circuit 227y, the T terminal is connected to the output of transmitter 224, and the R terminal is connected to the input of receiver 223.

[0100] Electrode selection circuit 227x is a switching element for selectively connecting multiple sensor electrodes 18X to the common terminal of switch 226x. That is, electrode selection circuit 227x is configured to simultaneously connect at least some of the multiple sensor electrodes 18X to the common terminal of switch 226x. Electrode selection circuit 227y is a switching element for selectively connecting multiple sensor electrodes 18Y to the common terminal of switch 226y. That is, electrode selection circuit 227y is configured to simultaneously connect at least some of the multiple sensor electrodes 18Y to the common terminal of switch 226y.

[0101] Four control signals, sTRx, sTRy, selX, and selY, are supplied from logic unit 222 to selector 225. Specifically, control signal sTRx is supplied to switch 226x, control signal sTRy is supplied to switch 226y, control signal selX is supplied to electrode selection circuit 227x, and control signal selY is supplied to electrode selection circuit 227y. Logic unit 222 controls the switches of selector 225 using the four control signals sTRx, sTRy, selX, and selY, thereby selectively transmitting uplink signals US and receiving downlink signals DS.

[0102] <Effects of the First Embodiment>

[0103] As described above, the stylus 16 is a device used together with an electronic device 14 having an electrostatic capacitance touch sensor 20 including a sensor electrode group 18 arranged in a planar shape, and comprises: a shell 42, used as a reference potential; a tip electrode 32 (first electrode); a ring electrode 34 (second electrode), different from the tip electrode 32; a first receiving circuit 50, grounded to the shell 42, and receiving an uplink signal US1 (transmitting signal) sent from the electronic device 14 via an electrostatic coupling formed between the tip electrode 32 and the sensor electrode group 18; a second receiving circuit 52, grounded to the shell 42, and receiving an uplink signal US2 (transmitting signal) sent from the electronic device 14 via an electrostatic coupling formed between the ring electrode 34 and the sensor electrode group 18; and an MCU44 (control circuit), which performs reception control on the first receiving circuit 50 and the second receiving circuit 52.

[0104] For example, when a user's human body BD contacts the touch surface 12 of the electronic device 14, electrostatic coupling may form between the human body BD and the sensor electrode group 18, causing an uplink signal US from the electronic device 14 to be sensed at the contact site of the human body BD. Therefore, a first receiving circuit 50 for receiving the uplink signal US1 sensed at the tip electrode 32 and a second receiving circuit 52 for receiving the uplink signal US2 sensed at the ring electrode 34 are provided, each receiving a transmission signal from two electrodes having different relative positions and postures relative to the contact site of the human body BD. Furthermore, by grounding the first receiving circuit 50 and the second receiving circuit 52 to the common GND potential of the housing 42, the degree to which fluctuations in the GND potential caused by the signals sensed at the human body BD affect each receiving circuit can be spatially and temporally offset.

[0105] like Figure 10As shown, when the human body BD is in contact with the touch surface 12 (during reception of the third and fourth positions), the GND potential of the housing 42 changes according to the waveform of the uplink signal US. In this case, the first receiving circuit 50 on one side cannot correctly detect the uplink signal US1 (first data DAT1), but the second receiving circuit 52 on the other side can correctly detect the uplink signal US2 (second data DAT2). Alternatively, Figure 11 As shown, the second receiving circuit 52 on one side cannot correctly detect the uplink signal US2 (second data DAT2), but the first receiving circuit 50 on the other side can correctly detect the uplink signal US1 (first data DAT1).

[0106] In this way, the possibility of "even if the receiving circuit on one side fails to function locally and suddenly due to the delicate balance between the electrode of the stylus 16 and the contact part of the human body BD, the receiving circuit on the other side will function as planned" becomes higher, which can prevent the signal induced in the electrode from being temporarily undetectable due to the fluctuation of the above-mentioned GND potential.

[0107] In particular, the first receiving circuit 50 may include an amplifier circuit 66a (first amplifier circuit) connected to the ground of the housing 42 and amplifying the signal induced by the tip electrode 32, and the second receiving circuit 52 may include an amplifier circuit 66b (second amplifier circuit) connected to the ground of the housing 42 and amplifying the signal induced by the ring electrode 34. The amplifier circuits 66a and 66b are susceptible to fluctuations in their operation relative to the GND potential, and thus the above-described suppression effect is more pronounced.

[0108] Alternatively, the tip electrode 32 and the ring electrode 34 may be provided on the end side of the housing 42 and have different shapes. This facilitates a difference in the waveforms of the uplink signals US1 and US2 sensed when the end side of the housing 42 (that is, the stylus 16) is directed toward the electronic device 14, further reducing the possibility of both uplink signals US1 and US2 being undetectable.

[0109] Alternatively, the tip electrode 32 and the ring electrode 34 may be spaced apart relative to the direction of the pen shaft. This makes it easier for the stylus 16 to face the electronic device 14, and the difference in reception strength between the uplink signals US1 and US2 from the sensor electrode group 18 becomes apparent. This further reduces the likelihood of both uplink signals US1 and US2 being undetectable.

[0110] [Second embodiment]

[0111] Next, refer to Figures 12 to 16While the stylus pen and the integrated circuit according to the second embodiment of the present invention are described, the same configurations and functions as those in the first embodiment are sometimes denoted by the same reference numerals and their descriptions are omitted.

[0112] Figure 12 This is a block diagram of a circuit board 102 (integrated circuit) included in a stylus pen 100 according to a second embodiment of the present invention. Circuit board 102 includes an MCU 104 (control circuit), a first switch 106 , a second switch 108 , a receiving circuit 110 (or receiving circuit 140 ), and a transmitting circuit 54 similar to that of the first embodiment.

[0113] MCU 104 is a unit that performs overall control over various components of stylus pen 100. MCU 104 is configured to receive uplink signals US1 and US2 from electronic device 14 by performing desired reception control on receiving circuit 110. Furthermore, MCU 104 is configured to transmit downlink signals DS to electronic device 14 by performing desired transmission control on transmitting circuit 54.

[0114] The first switch 106 is a switching element configured to connect a common terminal to either an R terminal or a T terminal. The common terminal of the first switch 106 is connected to the tip electrode 32, the R terminal is connected to the first input terminal of the receiving circuit 110, and the T terminal is connected to the output terminal of the transmitting circuit 54. The MCU 104 controls the switching of the first switch 106 to selectively receive the uplink signal US1 and transmit the downlink signal DS.

[0115] The second switch 108 is a switching element configured to connect a common terminal to either the R terminal or the T terminal. The common terminal of the second switch 108 is connected to the annular electrode 34, the R terminal is connected to the second input terminal of the receiving circuit 110, and the T terminal is connected to the output terminal of the transmitting circuit 54. The MCU 104 controls the switching of the second switch 108 to selectively receive the uplink signal US2 and transmit the downlink signal DS.

[0116] The receiving circuits 110 and 140 demodulate at least one of the uplink signal US1 sensed by the tip electrode 32 and the uplink signal US2 sensed by the ring electrode 34 and output the demodulated data DAT to the MCU 104. Here, the ground terminals of the receiving circuits 110 and 140 are connected to the ground of the housing 42 of the stylus pen 100.

[0117] <First example>

[0118] First, refer to Figure 13 and Figure 14The specific structure of the receiving circuit 110 will be described below. The receiving circuit 110 of the first example includes a first receiving system 112 , a second receiving system 114 , and a processing circuit 116 .

[0119] Figure 13 This figure shows a first example of the specific configuration of first receiving system 112 and second receiving system 114. First receiving system 112 is an analog circuit configured as a differential circuit 64a and an amplifier circuit 66a (first amplifier circuit). Similarly, second receiving system 114 is an analog circuit configured as a differential circuit 64b and an amplifier circuit 66b (first amplifier circuit).

[0120] Differentiation circuit 64a is a circuit that differentiates uplink signal US1 sensed by tip electrode 32 to generate a differential signal, and is comprised of a capacitor, a resistor, and a buffer. Differentiation circuit 64b is a circuit that differentiates uplink signal US2 sensed by ring electrode 34 to generate a differential signal, and is comprised of a capacitor, a resistor, and a buffer. The time constant of differentiation circuit 64a is preferably equal to the time constant of differentiation circuit 64b, but may be different from the time constant of differentiation circuit 64b.

[0121] Amplifier circuit 66a amplifies output signal DO1 of differential circuit 64a, has an input terminal connected to differential circuit 64a, and has a ground terminal connected to housing 42. Amplifier circuit 66b amplifies output signal DO2 of differential circuit 64b, has an input terminal connected to differential circuit 64b, and has a ground terminal connected to housing 42.

[0122] Figure 14 1 is a diagram showing a first example of a specific configuration of the processing circuit 116. The processing circuit 116 is configured as follows in addition to the first embodiment ( Figure 6 and Figure 7 ) In addition to the same digital circuit 62 and storage circuit 74, it also includes two rising detection circuits 121, 122, two falling detection circuits 123, 124 and a synthesis circuit 126.

[0123] Rising edge detection circuit 121 detects a rising edge in output signal AO1 from first receiving system 112 and, as a result of this detection, outputs edge signal Er1 indicating the timing of the rising edge. Rising edge detection circuit 122 detects a rising edge in output signal AO2 from second receiving system 114 and, as a result of this detection, outputs edge signal Er2 indicating the timing of the rising edge.

[0124] Fall detection circuit 123 detects a falling edge in output signal AO1 of first receiving system 112 and outputs edge signal Ef1 indicating the timing of the fall as a result of the detection. Fall detection circuit 124 detects a falling edge in output signal AO2 of second receiving system 114 and outputs edge signal Ef2 indicating the timing of the fall as a result of the detection.

[0125] Synthesis circuit 126 synthesizes the four edge signals Er1, Er2, Ef1, and Ef2 to output a synthesized signal (binarized signal) that reconstructs the waveform of the uplink signal US. Synthesis circuit 126 is composed of two logical OR circuits 132 and 134 and an SR latch circuit 136. Logical OR circuit 132 outputs the logical OR of edge signal Er1, which indicates a rising edge of output signal AO1, and edge signal Er2, which indicates a rising edge of output signal AO2. Logical OR circuit 134 outputs the logical OR of edge signal Ef1, which indicates a falling edge of output signal AO1, and edge signal Ef2, which indicates a falling edge of output signal AO2. SR latch circuit 136 receives the output signal of logical OR circuit 132 as its S input and the output signal of logical OR circuit 134 as its R input.

[0126] Digital circuit 62 detects data DAT based on output signal CO from synthesis circuit 126. Specifically, matched filter 70, which forms part of digital circuit 62, detects data DAT represented by uplink signal US by performing a correlation operation between output signal CO, which is sequentially supplied as a chip string, and comparison pattern PTc read from storage circuit 74.

[0127] Thus, the receiving circuit 110 ( Figure 14 The processing circuit 116 includes a synthesizing circuit 126 that synthesizes a first processed signal (here, edge signals Er1 and Ef1) obtained by processing the output signal AO1 (first amplified signal) of the amplifier circuit 66a and a second processed signal (here, edge signals Er2 and Ef2) obtained by processing the output signal AO2 (second amplified signal) of the amplifier circuit 66b; and a digital circuit 62 (detection circuit) that detects data DAT represented by the uplink signal US by performing a correlation operation between the output signal CO (synthesized signal) of the synthesizing circuit 126 and a comparison pattern PTc corresponding to the uplink signal US. Alternatively, the synthesizing circuit 126 may synthesize the output signal AO1 of the amplifier circuit 66a and the output signal AO2 of the amplifier circuit 66b.

[0128] <Second Example>

[0129] Next, refer to Figure 15 and Figure 16The specific structure of the receiving circuit 140 will be described below. The receiving circuit 140 of the second example includes a first receiving system 142 , a second receiving system 144 , and a processing circuit 146 .

[0130] Figure 15 This is a diagram showing a second example of the specific configuration of the first receiving system 142 and the second receiving system 144. Figure 6 The analog circuit 60a is similar to the analog circuit 60a, which includes an amplifier circuit 66a (first amplifier circuit) and a ΔΣ type ADC 68a. The second receiving system 144 is connected to Figure 7 Similarly, the analog circuit 60b is a circuit including an amplifier circuit 66b (first amplifier circuit) and a ΔΣ type ADC 68b.

[0131] Figure 16 This figure shows a second example of the specific configuration of processing circuit 146. This processing circuit 146 is configured to include, in addition to the aforementioned storage circuit 74, a digital circuit 150 having a function different from that of the first embodiment. This digital circuit 150 includes, in addition to the aforementioned matched filter 70, a switch 152 and a data restoration unit 154.

[0132] Switch 152 is a switching element configured such that its common terminal is connected to either the R1 terminal or the R2 terminal. The common terminal of switch 152 is connected to data recovery unit 154, while the R1 terminal is connected to the output of first receiving system 142 and the R2 terminal is connected to the output of second receiving system 144. It is assumed here that switch 152 is normally connected to the R1 terminal.

[0133] Matched filter 70 has a function of detecting a data signal corresponding to uplink signal US by performing a correlation operation between output signal SO selectively output from switch 152 and comparison pattern PTc read from storage circuit 74. Hereinafter, the correlation operation performed when output signal CO1 is selected by switch 152 is referred to as a "first correlation operation," and the correlation operation performed when output signal CO2 is selected by switch 152 is referred to as a "second correlation operation."

[0134] Data restoration unit 154 has the function of restoring the data signal detected by matched filter 70 according to known rules and outputting data DAT. When the common terminal of switch 152 is connected to terminal R1 and matched filter 70 is able to detect the data signal through the first correlation operation, data restoration unit 154 sequentially outputs data DAT corresponding to the data signal. However, if matched filter 70 is unable to detect a new data signal through the first correlation operation, data restoration unit 154 controls switch 152 so that the common terminal is connected to terminal R2.

[0135] Furthermore, when the common terminal of switch 152 is connected to the R2 terminal and the matched filter 70 is able to detect the data signal through the second correlation operation, the data restoration unit 154 sequentially outputs data DAT corresponding to the data signal. It should be noted that the data restoration unit 154 may also control the switch 152 so as to restore the connection destination to its original state if [1] a predetermined time has elapsed since the switch 152 was switched or [2] the matched filter 70 is no longer able to detect the data signal through the second correlation operation.

[0136] Thus, the receiving circuit 140 ( Figure 16 The processing circuit 146 may include a digital circuit 150 (detection circuit) for detecting data DAT represented by the uplink signal US through a first correlation operation or a second correlation operation. The first correlation operation is a correlation operation between a first processed signal (here, output signal CO1) obtained by processing the output signal AO1 (first amplified signal) of the amplifier circuit 66a and a comparison pattern PTc corresponding to the uplink signal US1. The second correlation operation is a correlation operation between a second processed signal (here, output signal CO2) obtained by processing the output signal AO2 of the amplifier circuit 66b and a comparison pattern PTc corresponding to the uplink signal US2. Alternatively, the digital circuit 150 may perform a first correlation operation between the output signal AO1 of the amplifier circuit 66a and the comparison pattern PTc, and a second correlation operation between the output signal AO2 of the amplifier circuit 66b and the comparison pattern PTc.

[0137] <Effects of the Second Embodiment>

[0138] As described above, the stylus pen 100 includes: a shell 42, which is used as a reference potential; a tip electrode 32 (first electrode); a ring electrode 34 (second electrode), which is different from the tip electrode 32; receiving circuits 110 and 140, which are circuits that receive transmission signals sent from the electronic device 14 via electrostatic coupling formed between the tip electrode 32 and the sensor electrode group 18 and between the ring electrode 34 and the sensor electrode group 18, respectively, and are constructed to include an amplifier circuit 66a (first amplifier circuit) and an amplifier circuit 66b (second amplifier circuit) independent of the amplifier circuit 66a, the amplifier circuit 66a is grounded to the shell 42 and amplifies the signal induced in the tip electrode 32, and the amplifier circuit 66b is grounded to the shell 42 and amplifies the signal induced in the ring electrode 34; and MCU104 (control circuit) that controls the reception of the receiving circuits 110 and 140.

[0139] For example, when the user's human body BD contacts the touch surface 12 of the electronic device 14, electrostatic coupling may be formed between the human body BD and the sensor electrode group 18, and an uplink signal US from the electronic device 14 may be sensed at the contact portion of the human body BD. Therefore, an amplifier circuit 66a for amplifying the signal sensed at the tip electrode 32 and an amplifier circuit 66b for amplifying the signal sensed at the ring electrode 34 are provided in the receiving circuits 110 and 140, respectively, so that transmission signals are input from two electrodes having different relative positional relationships with the contact portion of the human body BD.

[0140] Furthermore, by grounding amplifier circuits 66a and 66b to the common GND potential of housing 42, the effects of GND potential fluctuations caused by signals induced by human body BD on each amplifier circuit can be spatially and temporally offset. This increases the likelihood that even if one amplifier circuit partially and suddenly fails to function due to the delicate balance between the contact area between the stylus pen 100 electrode and human body BD, the other amplifier circuit will function as intended. This prevents the signals induced at the electrodes from being temporarily undetectable due to GND potential fluctuations.

[0141] Alternatively, the tip electrode 32 and the ring electrode 34 may be provided on the end side of the housing 42 and have different shapes. Alternatively, the tip electrode 32 and the ring electrode 34 may be arranged apart relative to the direction of the pen shaft. This provides the same operational effects as those of the first embodiment (i.e., suppression of simultaneous non-detection).

[0142] [Modification]

[0143] It should be noted that the present invention is not limited to the first and second embodiments described above, and can be freely modified without departing from the scope of the present invention. Alternatively, the various structures can be arbitrarily combined within the scope that does not cause technical contradictions.

[0144] The “first and second receiving circuits” in the first embodiment described above may be respectively referred to as “first and second receiving channels” or “first and second detecting circuits”.

[0145] The stylus pen 16 in the first embodiment described above includes two electrodes and two receiving circuits, but the number of electrodes and receiving circuits is not limited to this. For example, three or more electrodes and three or more receiving circuits may be provided, or all or only a portion of these may be used. Similarly, the number of electrodes and receiving circuits in the second embodiment may be appropriately modified.

[0146] The second receiving circuit 52 in the first embodiment has the same structure as the first receiving circuit 50, but may have different structures. For example, a ΔΣ type conversion circuit may be used in the first receiving circuit 50 (see Figure 7 ), and an edge extraction type conversion circuit is used in the second receiving circuit 52 (refer to Figure 14 Similarly, the circuit structure of the receiving system in the second embodiment may be appropriately modified. Sometimes, by switching between multiple receiving circuits (or receiving systems) with different circuit characteristics, optimization of operations, including improvement of receiving sensitivity and reduction of power consumption, is sought.

[0147] While the stylus 16 in the first embodiment described above receives a single uplink signal US, it can also be configured to simultaneously receive multiple uplink signals US via multiple receiving circuits. Specifically, after the stylus obtains the frequency band or code pattern type of the uplink signal US, the multiple detection circuits can perform correlation operations using the corresponding comparison patterns PTc.

[0148] In addition, if Figure 17 As shown, the circuit boards 38 and 102 may be configured to receive signals induced from two electrodes via a differential amplifier circuit. Figure 17 (a) corresponds to the partial diagram in the first embodiment, and Figure 17 (b) corresponds to a partial view of the second embodiment. In this example, the positive input terminal of amplifier circuit 66a is connected to the tip electrode 32, and the negative input terminal is connected to the ring electrode 34. The positive input terminal of amplifier circuit 66b is connected to the tip electrode 32, and the negative input terminal is connected to the housing 42.

[0149] Description of labels

[0150] 10 Position detection system, 14 Electronic device, 16, 100 Stylus, 18 Sensor electrode group, 20 Touch sensor, 22 Touch IC, 24 Host processor, 26 Display panel, 32 Tip electrode (first electrode), 34 Ring electrode (second electrode), 38, 102 Circuit substrate (integrated circuit), 42 Housing, 44, 104 MCU (control circuit), 50 First receiving circuit, 52 Second receiving circuit, 62a Digital circuit (first detection circuit), 62b Digital circuit (second detection circuit), 66a Amplifying circuit (first amplifying circuit), 66b Amplifying circuit (second amplifying circuit), 110, 140 Receiving circuit, 112, 142 First receiving system, 114, 144 Second receiving system, 116, 146 Processing circuit, 150 Digital circuit (detection circuit), DAT data, DAT1 first data, DAT2 second data, DS downlink signal, US, US1, US2 uplink signals.

Claims

1. A stylus pen for use with an electronic device having an electrostatic capacitance touch sensor including a sensor electrode group arranged in a planar shape. It is characterized in that have: The housing is used as a reference potential; a first electrode; a second electrode, different from the first electrode; a first receiving circuit connected to the housing ground and receiving a transmission signal transmitted from the electronic device via electrostatic coupling formed between the first electrode and the sensor electrode group; a second receiving circuit connected to the housing ground and receiving a transmission signal transmitted from the electronic device via electrostatic coupling formed between the second electrode and the sensor electrode group; and a control circuit for controlling reception of the first receiving circuit and the second receiving circuit; The first receiving circuit includes a first amplifier circuit connected to the housing ground and amplifying the signal induced at the first electrode. The second receiving circuit includes a second amplifying circuit connected to the housing ground and amplifying the signal induced at the second electrode. The first receiving circuit further includes a first detection circuit that detects first data represented by the transmission signal by performing a correlation operation between a first amplified signal output from the first amplifying circuit and a comparison pattern corresponding to the transmission signal, or detects the first data represented by the transmission signal by performing a correlation operation between a first processed signal obtained by processing the first amplified signal and a comparison pattern corresponding to the transmission signal. The second receiving circuit further includes a second detection circuit that detects second data represented by the transmission signal by performing a correlation operation between a second amplified signal output from the second amplifying circuit and a comparison pattern corresponding to the transmission signal, or detects the second data represented by the transmission signal by performing a correlation operation between a second processed signal obtained by processing the second amplified signal and the comparison pattern corresponding to the transmission signal. The control circuit obtains the first data from the first receiving circuit and obtains the second data from the second receiving circuit.

2. The stylus pen according to claim 1, wherein: The control circuit performs data processing using the first data while the first data can be obtained from the first receiving circuit. The control circuit performs data processing using the second data obtained from the second receiving circuit while the first data cannot be obtained from the first receiving circuit.

3. The touch pen according to claim 1, wherein: The first electrode and the second electrode are provided on an end side of the housing and have different shapes.

4. The stylus pen according to claim 1, wherein: The first electrode and the second electrode are arranged to be separated from each other with respect to the direction of the pen axis.

5. A stylus pen for use with an electronic device having an electrostatic capacitance touch sensor including a group of sensor electrodes arranged in a planar shape. It is characterized in that have: The housing is used as a reference potential; a first electrode; a second electrode, different from the first electrode; a receiving circuit for receiving a transmission signal transmitted from the electronic device via electrostatic coupling formed between the first electrode and the sensor electrode group and between the second electrode and the sensor electrode group, the receiving circuit including a first amplifying circuit and a second amplifying circuit independent of the first amplifying circuit, the first amplifying circuit being grounded to the housing and amplifying a signal induced at the first electrode, and the second amplifying circuit being grounded to the housing and amplifying a signal induced at the second electrode; and A control circuit performs reception control on the receiving circuit, The receiving circuit further comprises: a synthesizing circuit for synthesizing a first amplified signal output from the first amplifying circuit and a second amplified signal output from the second amplifying circuit, or synthesizing a first processed signal obtained by processing the first amplified signal and a second processed signal obtained by processing the second amplified signal; and a detection circuit that detects data represented by the transmission signal by performing a correlation operation between a synthesis signal synthesized by the synthesis circuit and a comparison pattern corresponding to the transmission signal, The control circuit performs data processing using the data acquired from the receiving circuit.

6. The touch pen according to claim 5, wherein: The first electrode and the second electrode are provided on an end side of the housing and have different shapes.

7. The touch pen according to claim 5, wherein: The first electrode and the second electrode are arranged to be separated from each other with respect to the direction of the pen axis.

8. A stylus pen for use with an electronic device having an electrostatic capacitance touch sensor including a sensor electrode group arranged in a planar shape. It is characterized in that have: The housing is used as a reference potential; a first electrode; a second electrode, different from the first electrode; a receiving circuit for receiving a transmission signal transmitted from the electronic device via electrostatic coupling formed between the first electrode and the sensor electrode group and between the second electrode and the sensor electrode group, the receiving circuit including a first amplifying circuit and a second amplifying circuit independent of the first amplifying circuit, the first amplifying circuit being grounded to the housing and amplifying a signal induced at the first electrode, and the second amplifying circuit being grounded to the housing and amplifying a signal induced at the second electrode; and A control circuit performs reception control on the receiving circuit, The receiving circuit further includes a detection circuit for detecting data represented by the transmission signal by a first correlation calculation or a second correlation calculation, wherein the first correlation calculation is a correlation calculation between a first amplified signal output from the first amplifying circuit and a comparison pattern corresponding to the transmission signal, or a correlation calculation between a first processed signal obtained by processing the first amplified signal and the comparison pattern corresponding to the transmission signal; and the second correlation calculation is a correlation calculation between a second amplified signal output from the second amplifying circuit and the comparison pattern corresponding to the transmission signal, or a correlation calculation between a second processed signal obtained by processing the second amplified signal and the comparison pattern corresponding to the transmission signal. The control circuit performs data processing using the data acquired from the receiving circuit.

9. The touch pen according to claim 8, wherein: The first electrode and the second electrode are provided on an end side of the housing and have different shapes.

10. The touch pen according to claim 8, wherein: The first electrode and the second electrode are arranged to be separated from each other with respect to the direction of the pen axis.

11. An integrated circuit used in a stylus pen, characterized in that: The stylus pen includes a housing used as a reference potential, a first electrode, and a second electrode different from the first electrode, and is used with an electronic device including an electrostatic capacitance touch sensor including a sensor electrode group arranged in a planar shape. The integrated circuit comprises: a first receiving circuit connected to the housing ground and receiving a transmission signal transmitted from the electronic device via electrostatic coupling formed between the first electrode and the sensor electrode group; a second receiving circuit connected to the housing ground and receiving a transmission signal transmitted from the electronic device via electrostatic coupling formed between the second electrode and the sensor electrode group; and a control circuit for controlling reception of the first receiving circuit and the second receiving circuit; The first receiving circuit includes a first amplifier circuit connected to the housing ground and amplifying the signal induced at the first electrode. The second receiving circuit includes a second amplifying circuit connected to the housing ground and amplifying the signal induced at the second electrode. The first receiving circuit further includes a first detection circuit configured to detect first data represented by the transmission signal by performing a correlation operation between a first amplified signal output from the first amplifying circuit or a first processed signal obtained by processing the first amplified signal and a comparison pattern corresponding to the transmission signal. The second receiving circuit further includes a second detection circuit configured to detect second data represented by the transmission signal by performing a correlation operation between a second amplified signal output from the second amplifying circuit or a second processed signal obtained by processing the second amplified signal and a comparison pattern corresponding to the transmission signal. The control circuit obtains the first data from the first receiving circuit and obtains the second data from the second receiving circuit.

12. An integrated circuit used in a stylus pen, characterized in that: The stylus pen includes a housing used as a reference potential, a first electrode, and a second electrode different from the first electrode, and is used with an electronic device including an electrostatic capacitance touch sensor including a sensor electrode group arranged in a planar shape. The integrated circuit comprises: a receiving circuit for receiving a transmission signal transmitted from the electronic device via electrostatic coupling formed between the first electrode and the sensor electrode group and between the second electrode and the sensor electrode group, the receiving circuit including a first amplifying circuit and a second amplifying circuit independent of the first amplifying circuit, the first amplifying circuit being grounded to the housing and amplifying a signal induced at the first electrode, and the second amplifying circuit being grounded to the housing and amplifying a signal induced at the second electrode; and A control circuit performs reception control on the receiving circuit, The receiving circuit further comprises: a synthesizing circuit for synthesizing a first amplified signal output from the first amplifying circuit and a second amplified signal output from the second amplifying circuit, or synthesizing a first processed signal obtained by processing the first amplified signal and a second processed signal obtained by processing the second amplified signal; and a detection circuit that detects data represented by the transmission signal by performing a correlation operation between a synthesis signal synthesized by the synthesis circuit and a comparison pattern corresponding to the transmission signal, The control circuit performs data processing using the data acquired from the receiving circuit.

13. An integrated circuit used in a stylus pen, characterized in that: The stylus pen includes a housing used as a reference potential, a first electrode, and a second electrode different from the first electrode, and is used with an electronic device including an electrostatic capacitance touch sensor including a sensor electrode group arranged in a planar shape. The integrated circuit comprises: a receiving circuit for receiving a transmission signal transmitted from the electronic device via electrostatic coupling formed between the first electrode and the sensor electrode group and between the second electrode and the sensor electrode group, the receiving circuit including a first amplifying circuit and a second amplifying circuit independent of the first amplifying circuit, the first amplifying circuit being grounded to the housing and amplifying a signal induced at the first electrode, and the second amplifying circuit being grounded to the housing and amplifying a signal induced at the second electrode; and A control circuit performs reception control on the receiving circuit, The receiving circuit further includes a detection circuit for detecting data represented by the transmission signal by a first correlation calculation or a second correlation calculation, wherein the first correlation calculation is a correlation calculation between a first amplified signal output from the first amplifying circuit and a comparison pattern corresponding to the transmission signal, or a correlation calculation between a first processed signal obtained by processing the first amplified signal and the comparison pattern corresponding to the transmission signal; and the second correlation calculation is a correlation calculation between a second amplified signal output from the second amplifying circuit and the comparison pattern corresponding to the transmission signal, or a correlation calculation between a second processed signal obtained by processing the second amplified signal and the comparison pattern corresponding to the transmission signal. The control circuit performs data processing using the data acquired from the receiving circuit.

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