Touch panel system and electronic device

In a touch panel system (1) of the present invention, a stylus pen (3) produces output that indicates that a quantitative characteristic value is increased from the characteristic value of a previous output by using a waveform that corresponds to an (L+1)-th drive line (DLL+1) other than L numbers of drive lines (DL1 to DLL) and, meanwhile, produces output that indicates that the quantitative characteristic value is decreased from the characteristic value of the previous output by using a waveform that corresponds to an (L+2)-th drive line (DLL+2) other than the L numbers of drive lines (DL1 to DLL). A touch panel controller (10) includes a conversion output unit (19) that converts and outputs the quantitative characteristic value by using the sum of the initial value of the quantitative characteristic value and the number of outputs×the unit amount of increase or decrease in the waveform that corresponds to the (L+1)-th drive line (DLL+1) or in the waveform that corresponds to the (L+2)-th drive line (DLL+2).

TECHNICAL FIELD

The present invention relates to a touch panel system and an electronic device that detect the position of the touch of a touch pen on a touch panel which has electrostatic capacitances formed at each intersection of a plurality of first signal lines and a plurality of second signal lines. Specifically, the invention relates to a method for coping with a case where there are many types of information of an electronic pen when a touch pen is configured of an electronic pen that signals can be input into and output from.

BACKGROUND ART

In the related art, there is known, for example, a touch panel system disclosed in PTL 1 as a touch panel system that detects the position of the touch of a touch pen on a touch panel which has electrostatic capacitances formed at each intersection of a plurality of first signal lines and a plurality of second signal lines.

The touch panel system disclosed in PTL 1 includes a plurality of electronic pens, a panel main body that includes a touch face on which a touch operation is performed by the electronic pens and a finger and in which a plurality of transmission electrodes that runs parallel to each other and a plurality of reception electrodes that runs parallel to each other are arranged into a lattice, a transmission unit that applies a drive signal to the transmission electrodes, a reception unit that receives a response signal which is output from the reception electrodes in response to the drive signal applied to the transmission electrodes and outputs detection data for each intersection of the electrodes, and a control unit that detects the position of a touch on the basis of the detection data which is output from the reception unit, in which the transmission unit applies a pen synchronization signal that synchronizes the transmission and reception of a pen identifiable signal between the electronic pens and the reception unit to the transmission electrodes, the electronic pens transmit the pen identifiable signal to the reception electrodes in response to the detection of the pen synchronization signal in the transmission electrodes at the time of a touch operation, and the control unit, on the basis of the pen synchronization signal that the reception unit receives through the reception electrodes, identifies a pointed object on which a touch operation is performed.

According to this configuration, a plurality of electronic pens can be used because each electronic pen transmits the pen identifiable signal to the reception electrodes in response to the detection of the pen synchronization signal from the transmission electrodes at the time of a touch operation and because the control unit, on the basis of the pen synchronization signal that the reception unit receives through the reception electrodes, identifies the electronic pen that performs the touch operation.

When an electronic pen that is provided with additional functions such as a pen pressure sensing function is used as the touch pen, it is necessary to transmit information that the electronic pen obtains to the touch panel controller.

In this case, for example, in the position detecting device disclosed in PTL 2, the electronic pen transmits information to the touch panel controller by using a signal that is configured of a plurality of types of codes which have different code patterns.

CITATION LIST

Patent Literature

SUMMARY OF INVENTION

Technical Problem

In such identification methods of PTL 1 and PTL 2, however, a problem arises when there are many types of information that is transmitted from the electronic pen. The number of types of code patterns increases, and, in turn, information has to be transmitted by a code pattern that has many bit digits. Thus, the amount of signals increases, and the identification of signals becomes complicated.

For example, when the electronic pen outputs a quantitative characteristic value such as in the case of representing a pen pressure value with 10 bits, it is necessary to assign 10 types of drive patterns to one electronic pen. In this case, more drive time is required in sequential driving. In parallel driving, a decoding range becomes wide, or it is difficult to increase the number of electronic pens.

The present invention is devised with consideration of the problem in the related art, and an object thereof is to provide a touch panel system and an electronic device that may simply transmit information in a short amount of time when an electronic pen that outputs a quantitative characteristic value having many types of information is used.

Solution to Problem

In order to resolve the problem, according to an aspect of the present invention, there is provided a touch panel system including a touch pen, a touch panel that has electrostatic capacitances formed at each intersection of K (K is an integer greater than or equal to two) numbers of first signal lines and L (L is an integer satisfying L≧K) numbers of second signal lines, and a touch panel controller, in which the touch panel controller outputs drive signals that drive the K numbers of the first signal lines or the L numbers of the second signal lines from a drive unit through L numbers of drive signal lines and receives input of detection signals from the K numbers of the first signal lines or the L numbers of the second signal lines detected by a detecting unit through L numbers of detection signal lines on the basis of a change in charges that is accumulated in the electrostatic capacitances due to the touch pen when the touch pen touches the touch panel, the touch pen is configured of an electronic pen that outputs a quantitative characteristic value, the electronic pen produces output that indicates that the quantitative characteristic value of the electronic pen is increased from the characteristic value of a previous output by using a waveform that corresponds to an (L+1)-th drive signal line other than the L numbers of the drive signal lines and, meanwhile, produces output that indicates that the quantitative characteristic value of the electronic pen is decreased from the characteristic value of the previous output by using a waveform that corresponds to an (L+2)-th drive signal line other than the L numbers of the drive signal lines, and the touch panel controller includes a conversion output unit that converts and outputs the quantitative characteristic value by using the sum of the initial value of the quantitative characteristic value and the number of outputs×the unit amount of increase or decrease in the waveform that corresponds to the (L+1)-th drive signal line or in the waveform that corresponds to the (L+2)-th drive signal line.

The representation of L+1 and L+2 is for representing drive signal lines other than the L numbers or the K numbers of drive signal lines, meaning that the drive signal lines are not actually connected to the touch panel. Thus, when the actual number of connection lines between the touch panel and the touch panel controller is less than L or K, a waveform that corresponds to an arbitrary drive signal line of the non-connected drive signal lines may be used.

In order to resolve the problem, according to another aspect of the present invention, there is provided an electronic device including the above touch panel system.

Advantageous Effects of Invention

According to the aspects of the present invention, the effect of providing a touch panel system and an electronic device that may simply transmit information in a short amount of time when an electronic pen that outputs a quantitative characteristic value having many types of information is used is achieved.

DESCRIPTION OF EMBODIMENTS

First Embodiment

An embodiment of the present invention will be described as follows on the basis ofFIG. 1toFIG. 16.

(Configuration of Touch Panel System)

A configuration of a touch panel system1of the present embodiment will be described on the basis ofFIG. 1andFIG. 2.FIG. 1is a block diagram illustrating a configuration of the touch panel system1of the present embodiment, andFIG. 2is an interconnect diagram illustrating a configuration of a touch panel disposed in the touch panel system.

The touch panel system1of the present embodiment, as illustrated inFIG. 1, is provided with a touch panel2, a stylus pen3as a touch pen and an electronic pen, and a touch panel controller10that drives the touch panel2and the stylus pen3.

The touch panel2, as illustrated inFIG. 2, is provided with horizontal signal lines HL1to HLKas K (K is a positive integer) numbers first signal lines that are plural lines arranged parallel to each other along the horizontal direction and vertical signal lines VL1to VLLas L (L is a positive integer) numbers of second signal lines that are plural lines arranged parallel to each other along the vertical direction. Electrostatic capacitances C11to CKL are generated at each intersection of the horizontal signal lines HL1to HLKand the vertical signal lines VL1to VLL. While K and L may be either the same or different, the present embodiment will be described on the assumption that L≧K. In addition, while the vertical signal lines VL1to VLLvertically intersect the horizontal signal lines HL1to HLKin the present embodiment, the present invention is not necessarily limited to this, provided that both intersect each other.

The touch panel2, although preferably having a width such that a hand holding the stylus pen3can be put on the touch panel2, may have a size used in a smartphone.

The stylus pen3, in the present embodiment, is not only a touch pen that is configured of a conductor and that is simply used for touching the touch panel2but also a pen that signals can be input into and output from. As described below, a synchronization signal detector circuit36is disposed in the stylus pen3so that a synchronization signal for synchronization with a dedicated synchronization signal generated by a timing generator14of the touch panel controller10is received and input into the stylus pen3.

The touch panel controller10, as illustrated inFIG. 2, is provided with a multiplexer11, a driver12, a sense amplifier13, the timing generator14, an AD converter15, capacitance distribution calculating unit16, a touch recognizing unit17, and a pen position detecting unit18.

The driver12is configured to apply voltage to drive lines DL1to DLKor to drive lines DL1to DLLin correspondence with driving of the horizontal signal lines HL1to HLKor driving of the vertical signal lines VL1to VLLin the touch panel2.

The sense amplifier13reads a signal of initial charges and a linear summation signal through sense lines SL1to SLLand supplies the signal and the linear summation signal to the AD converter15. The initial charges of the signal correspond to each of the electrostatic capacitances C11to CKL of the touch panel2at the time of driving the horizontal signal lines HL1to HLKin a first signal line drive period. The linear summation signal corresponds to a first pen charge signal that is charges at the time of a touch which correspond to the electrostatic capacitances between the stylus pen3and each of the L numbers of the vertical signal lines VL1to VLLat the time of a touch. That is, when the stylus pen3approaches a position on the touch panel2while charges corresponding to each of the electrostatic capacitances C11to CKL are detected in the first signal line drive period, charges of the electrostatic capacitance at the position change. Thus, the changed changes of the electrostatic capacitance can be detected as a linear summation signal. Usually, when the stylus pen3approaches the touch panel2, each of the electrostatic capacitances C11to CKL at the approached position increases.

The sense amplifier13is configured to read a signal of initial charges and a linear summation signal through the sense lines SL1to SLKand to supply the signal and the linear summation signal to the AD converter15. The initial charges of the signal correspond to each of the electrostatic capacitances C11to CKL of the touch panel2at the time of driving the vertical signal lines VL1to VLLin a second signal line drive period. The linear summation signal corresponds to a second pen charge signal that is charges at the time of a touch which correspond to the electrostatic capacitances between the stylus pen3and each of the K numbers of the horizontal signal lines HL1to HLKat the time of a touch.

Next, the multiplexer11will be described on the basis ofFIG. 3.FIG. 3is a circuit diagram illustrating a configuration of a multiplexer that switches connections between the horizontal signal lines HL1to HLKor the vertical signal lines VL1to VLKto VLLdisposed in the touch panel2and the drive lines DL1to DLKto DLLconnected to the driver or the sense lines SL1to SLKto SLLconnected to the sense amplifier13.

The multiplexer11is a connection switch circuit that switches connections between a plurality of inputs and a plurality of outputs. In the present embodiment, as illustrated inFIG. 3, the multiplexer11switches between a first connection state where the horizontal signal lines HL1to HLKare connected to the drive lines DL1to DLKof the driver12and where the vertical signal lines VL1to VLKto VLLare connected to the sense lines SL1to SLKto SLLof the sense amplifier13and a second connection state where the horizontal signal lines HL1to HLKare connected to the sense lines SL1to SLKof the sense amplifier13and where the vertical signal lines VL1to VLKto VLLare connected to the drive lines DL1to DLKto DLLof the driver12.

In the multiplexer11, when the signal of a control line CL illustrated inFIG. 3is set to Low, the horizontal signal lines HL1to HLKare connected to the drive lines DL1to DLK, and the vertical signal lines VL1to VLLare connected to the sense lines SL1to SLL. Meanwhile, when the signal of the control line CL is set to High, the horizontal signal lines HL1to HLKare connected to the sense lines SL1to SLK, and the vertical signal lines VL1to VLLare connected to the drive lines DL1to DLL.

Next, the timing generator14illustrated inFIG. 1generates a signal that defines the operation of the driver12, a signal that defines the operation of the sense amplifier13, and a signal that defines the operation of the AD converter15and respectively supplies the signals to the driver12, the sense amplifier13, and the AD converter15. In addition, the timing generator14generates a synchronization signal. The touch panel controller10is configured to drive the horizontal signal lines HL1to HLKand the vertical signal lines VL1to VLLby using the synchronization signal generated by the timing generator14as a synchronization-dedicated signal.

Next, the AD converter15, during the first signal line drive period, performs AD conversion on charges that correspond to each of the electrostatic capacitances C11to CKL and that are read through the vertical signal lines VL1to VLLand through the sense lines SL1to SLLand on the linear summation signal that corresponds to the first pen charge signal which is charges corresponding to the electrostatic capacitances between the stylus pen3and each of the L numbers of the vertical signal lines VL1to VLL. The AD converter15supplies the AD-converted charges and linear summation signal to the capacitance distribution calculating unit16.

The AD converter15, during the second signal line drive period, performs AD conversion on charges that correspond to each of the electrostatic capacitances C11to CKL and that are read through the horizontal signal lines HL1to HLKand through the sense lines SL1to SLKand on the linear summation signal that corresponds to the second pen charge signal which is charges corresponding to the electrostatic capacitances between the stylus pen3and each of the K numbers of the horizontal signal lines HL1to HLK. The AD converter15supplies the AD-converted charges and linear summation signal to the capacitance distribution calculating unit16.

Next, the capacitance distribution calculating unit16, on the basis of the linear summation signal that includes the first pen charge signal and the second pen charge signal and on the basis of a code sequence based on driving, calculates the distribution of electrostatic capacitances on the touch panel2, the distribution of electrostatic capacitances between the stylus pen3and each of the L numbers of the vertical signal lines VL1to VLL, and the distribution of electrostatic capacitances between the stylus pen3and each of the K numbers of the horizontal signal lines HL1to HLK, supplies the distribution of electrostatic capacitances on the touch panel2to the touch recognizing unit17, and supplies the distribution of electrostatic capacitances between the stylus pen3and each of the L numbers of the vertical signal lines VL1to VLLand the distribution of electrostatic capacitances between the stylus pen3and the K numbers of the horizontal signal lines HL1to HLKto the pen position detecting unit18that is position detecting means. The touch recognizing unit17recognizes the position of a touch on the touch panel2on the basis of the distribution of electrostatic capacitances supplied from the capacitance distribution calculating unit16.

The pen position detecting unit18detects the position of the stylus pen3along the horizontal signal lines on the basis of the distribution of electrostatic capacitances between the stylus pen3and each of the L numbers of the vertical signal lines VL1to VLL. In addition, the pen position detecting unit18detects the position of the stylus pen3along the vertical signal lines on the basis of the distribution of electrostatic capacitances between the stylus pen3and each of the K numbers of the horizontal signal lines HL1to HLK.

(Detection Operation for Detecting Position of Touch of Touch Pen)

A detection operation for detecting the position of a touch of the stylus pen3in the touch panel system1having the above configuration will be described in a temporal manner below. Here, the detection operation will be described in a case where the stylus pen3is simply used as a touch pen.

First, in the first signal line drive period, in the first connection state where the horizontal signal lines HL1to HLKare connected to the drive lines DL1to DLKof the driver12and where the vertical signal lines VL1to VLLare connected to the sense lines SL1to SLLof the sense amplifier13, the driver12drives the horizontal signal lines HL1to HLKby applying voltage to the drive lines DL1to DLK.

Then, in the first signal line drive period, charges that are accumulated in each of the electrostatic capacitances C11to CKL by driving the horizontal signal lines HL1to HLKand L numbers of first linear summation signals that are based on the first pen charge signal which is charges corresponding to the electrostatic capacitances between the stylus pen3and each of the L numbers of vertical signal lines VL1to VLLat the time of the approach of the stylus pen3to the touch panel2are output from each of the L numbers of the vertical signal lines VL1to VLL.

The sense amplifier13reads the L numbers of the first linear summation signals that include the first pen charge signal through the multiplexer11and through the sense lines SL1to SLLand supplies the L numbers of the first linear summation signals to the AD converter15. The AD converter15performs AD conversion on the L numbers of the first linear summation signals that include the first pen charge signal and outputs the AD-converted L numbers of the first linear summation signals to the capacitance distribution calculating unit16.

Next, the first connection state is switched to the second connection state so as to change the drive signal and the sense signal of the horizontal signal lines HL1to HLKand the vertical signal lines VL1to VLL. That is, in the second connections state, the horizontal signal lines HL1to HLKare connected to the sense lines SL1to SLKof the sense amplifier13, and the vertical signal lines VL1to VLLare connected to the drive lines DL1to DLLof the driver12.

The driver12, afterward, drives the vertical signal lines VL1to VLLby applying voltage to the drive lines DL1to DLL.

Then, in the second signal line drive period, charges that are accumulated in each of the electrostatic capacitances C11to CKL by driving the vertical signal lines VL1to VLLand K numbers of second linear summation signals that are based on the second pen charge signal which is charges corresponding to the electrostatic capacitances between the stylus pen3and each of the K numbers of the horizontal signal lines HL1to HLKare output from each of the K numbers of the horizontal signal lines HL1to HLK. At this time, the sense amplifier13reads the K numbers of the second linear summation signals that include the second pen charge signal through the multiplexer11and through the sense lines SL1to SLKand supplies the K numbers of the second linear summation signals to the AD converter15. The AD converter15performs AD conversion on the K numbers of the second linear summation signals that include the second pen charge signal and outputs the AD-converted K numbers of the second linear summation signals to the capacitance distribution calculating unit16.

Next, in a position detecting process, the capacitance distribution calculating unit16calculates the distribution of electrostatic capacitances on the touch panel2and supplies the first linear summation signals that include the first pen charge signal, the second linear summation signals that include the second pen charge signal, and the distribution of electrostatic capacitances to the touch recognizing unit17. The capacitance distribution calculating unit16calculates the position of the stylus pen3along the horizontal signal lines and the position of the stylus pen3along the vertical signal lines and supplies the positions of the stylus pen3to the pen position detecting unit18.

The touch recognizing unit17, afterward, recognizes the position of a touch on the touch panel2on the basis of the distribution of electrostatic capacitances supplied from the capacitance distribution calculating unit16.

The pen position detecting unit18detects the position of the stylus pen3on the touch panel2on the basis of the position of the stylus pen3along the horizontal signal lines and the position of the stylus pen3along the vertical signal lines calculated by the capacitance distribution calculating unit16.

In the above description, in the present embodiment, both the horizontal signal lines HL1to HLKand the vertical signal lines VL1to VLLare driven in a parallel and simultaneous manner. That is, parallel driving is performed. However, not necessarily limited to this, driving of the K numbers of the horizontal signal lines HL1to HLKand driving of the L numbers of the vertical signal lines VL1to VLLin the touch panel2may be either parallel driving or sequential driving. Parallel driving means that the K numbers of the horizontal signal lines HL1to HLKor the L numbers of the vertical signal lines VL1to VLLare driven in a parallel and simultaneous manner, and sequential driving means that the K numbers of the horizontal signal lines HL1to HLKor the L numbers of the vertical signal lines VL1to VLLare sequentially driven in order from the horizontal signal line HL1or from the vertical signal line VL1. Parallel driving is preferable in terms of speed, and the present embodiment uses parallel driving.

As such, the touch panel system1of the present embodiment is provided with the touch panel2that has electrostatic capacitances formed at each intersection of the plurality of first signal lines and the plurality of second signal lines, the touch pen, and the touch panel controller10. The touch panel controller10, when repeatedly switching driving such that the horizontal signal lines HL1to HLKthat are the plurality of first signal lines are driven to output charge signals based on each electrostatic capacitance from each of the vertical signal lines VL1to VLLthat are the second signal lines during the first signal line drive period and such that the vertical signal lines VL1to VLLthat are the plurality of second signal lines are driven to output charge signals based on each electrostatic capacitance from each of the horizontal signal lines HL1to HLKthat are the first signal lines during the second signal line drive period, detects the position of a touch on the basis of a change in charges of the electrostatic capacitances due to the touch pen when the touch pen touches the touch panel2.

In the touch pen coordinate position detecting method in the touch panel system1having the above configuration, when the touch pen touches the touch panel2, a detected position in the first signal line drive period and a detected position in the second signal line drive period are represented at the same position. Meanwhile, an erroneous signal due to phantom noise that is caused by the touch of a hand, a finger, and the like of a human body, which receives electromagnetic noise, on the touch panel2, even when represented in the first signal line drive period by switching the first signal lines and the second signal lines, is not represented at the same position in the second signal line drive period. Therefore, by determining a detected position with a logical product of a detected position in the first signal line drive period and a detected position in the second signal line drive period, it is possible to distinguish a signal of a touch of the touch pen and an erroneous signal due to phantom noise and to remove the erroneous signal due to phantom noise.

Phantom noise is a noise that generates a detection signal based on static electricity at a position different from the position of a touch of the touch pen through a hand which holds the touch pen. Since the position where the detection signal is generated is different from the valid position of a touch of the touch pen, the detection signal is regarded as noise.

(Configuration of Stylus Pen and Pen Pressure Sensing Function)

The stylus pen3of the present embodiment includes a pen pressure sensor that is used to detect a pen pressure level which is a quantitative characteristic value. A configuration of the stylus pen3will be described on the basis ofFIG. 4.FIG. 4is a sectional view illustrating a configuration of the stylus pen3.

The stylus pen3, as illustrated inFIG. 4, includes a pen main body30that a user holds with the hand thereof and that includes a conductive holding portion30awhich is formed into a substantially cylindrical shape so that the user can hold with the hand thereof. A pen tip portion31that is pressed to the touch panel2at the time of a touch operation is disposed at the tip end of the pen main body30.

The pen tip portion31includes a pen tip cover31a, a pen tip axis31b, insulators31cand31cthat hold the pen tip cover31ain a manner capable of moving the pen tip cover31aforward in the axial direction, and a pen pressure sensor31dthat is disposed on the deep side of the pen tip axis31b.

The pen tip cover31ais made of insulating material, and the pen tip axis31bis made of conductive material such as metal or conductive synthetic resin material.

The pen pressure sensor31dis configured of, for example, a semiconductor piezoresistive pressure sensor in which a semiconductor strain gauge is formed on the surface of an unillustrated diaphragm. Therefore, when the pen tip cover31aof the pen tip portion31is pressed to the touch panel2at the time of a touch operation, the pen tip axis31bis pushed through the pen tip cover31aand presses the surface of the diaphragm of the pen pressure sensor31d. Accordingly, a change in electrical resistance due to a piezoresistive effect that is generated by the deformation of the diaphragm is converted into an electrical signal. Accordingly, the pressure of the stylus pen3can be detected. A principle of detecting the pressure of a pen is not necessarily limited to this. Other principles of detection can be used.

Disposed in the pen main body30are a connection switch32, a controller circuit33, operation changing switches34aand34b, a sense circuit35, the synchronization signal detector circuit36, a timing adjuster circuit37, and a drive circuit38. The connection switch32may be omitted. When the connection switch32is omitted, the output of the controller circuit33is connected to the pen tip axis31b.

The connection switch32is an electronic switch that is configured of a field-effect transistor (FET) or the like and is controlled in an ON-OFF manner by the controller circuit33. When the connection switch32is OFF, the pen tip cover31ais electrically disconnected from the holding portion30aof the pen main body30. At this time, since the component capacitance of the pen tip portion31is very small, the touch panel system1does not recognize approaching or abutting of the stylus pen3even when the pen tip cover31aapproaches the touch panel2.

Meanwhile, when the connection switch32is ON, the pen tip cover31ais electrically connected to the holding portion30aof the pen main body30through the pen tip axis31b, and a human body is conducted to the pen tip cover31athrough the holding portion30a. Accordingly, since a human body has a comparatively large electrostatic capacitance, when the stylus pen3approaches or touches the touch panel2, charges accumulated in each of the electrostatic capacitances C11to CKL of the touch panel2change, and the touch panel system1can detect the state of the touch of the stylus pen3.

Disposed in the stylus pen3are, for example, a push-type first operating switch39aand a push-type second operating switch39b. Functions assigned to the first operating switch39aand the second operating switch39bare performed through the controller circuit33by pushing the first operating switch39aand the second operating switch39b. Examples of a function assigned to the first operating switch39acan include an eraser function. The first operating switch39acan turn ON or OFF the eraser function. In addition, examples of a function assigned to the second operating switch39bcan include a mouse right-clicking function. The second operating switch39bcan turn ON or OFF the mouse right-clicking function.

The eraser function and the mouse right-clicking function are merely an example. The functions of the first operating switch39aand the second operating switch39bare not limited to the eraser function and the mouse right-clicking function. It is also possible to further dispose other operating switches to add other functions.

A signal of a touch of the stylus pen3on the touch panel2, that is, the first pen charge signal and the second pen charge signal indicating the position of a touch are detected by switching driving of the horizontal signal lines HL1to HLKand the vertical signal lines VL1to VLLas described above when the stylus pen3touches the touch panel2in a state where the connection switch32of the stylus pen3is ON.

In order to detect a detection signal of the pen pressure of the pen tip portion31in the stylus pen3, the present embodiment uses a method that matches the drive pattern of the drive circuit38of the stylus pen3to the drive pattern of the horizontal signal lines HLK+1and HLK+2(or later one) of the touch panel2driven by the touch panel controller10, that is, to the drive pattern of the (K+1)-th and (K+2)-th (or later) drive lines DLK+1and DLK+2(or later one) of the driver12in the first signal line drive period and matches the drive pattern of the drive circuit38to the drive pattern of the vertical signal lines VLL+1and VLL+2(or later one) of the touch panel2driven by the touch panel controller10, that is, to the drive pattern of the (L+1)-th and (L+2)-th (or later) drive lines DLL+1and DLL+2(or later one) of the driver12in the second signal line drive period. Here, the horizontal signal lines HLK+1and HLK+2(or later one) and the vertical signal lines VLL+1and VLL+2(or later one) do not actually exist. InFIG. 1andFIG. 2, although drive patterns may be different depending on the drive periods like the drive line DLK+1and the drive line DLL+1(K≠L), illustration is provided with a phantom line using the representation of the drive lines DLL+1and DLL+2for convenience of representation. The representation of the drive lines DLL+1and DLL+2will also be used in later descriptions.

Accordingly, in the touch panel controller10, an increasing or decreasing signal of the pen pressure sensor31din the stylus pen3can be obtained through the sense lines SL1to SLLby waveforms that correspond to the drive lines DLL+1and DLL+2. That is, in the present embodiment, by the waveforms that correspond to the drive lines DLL+1and DLL+2, an increasing or decreasing signal of the pen pressure sensor31din the stylus pen3is output, and the signal is detected by the sense lines SL1to SLLthrough the horizontal signal lines HL1to HLKor through the vertical signal lines VL1to VLLthat pass through the position of a touch on the touch panel2at that time.

As a consequence, the controller circuit33of the stylus pen3generates pen pressure information on the basis of the output of the pen pressure sensor31d, and the pen pressure information is output to the touch panel controller10by the waveforms that correspond to the drive lines DLL+1and DLL+2in response to a transmission instruction from the controller circuit33. A specific method for the output of the pen pressure sensor31dwill be described later.

(Basic Operation of Synchronization of Touch Panel Controller and Stylus Pen)

The stylus pen3of the present embodiment wirelessly transmits and receives signals with the touch panel controller10. Therefore, the pen tip portion31is driven with the same pattern as driving the drive line DLL+1or DLL+2in accordance with the timing of driving the drive lines DL1to DLLin the touch panel controller10. Therefore, the drive circuit38is disposed in the stylus pen3so that the stylus pen3can be driven in the same manner as the driver12of the touch panel controller10.

Driving of the drive lines DL1to DLLin the touch panel controller10is based on a drive timing that is generated by the timing generator14. Thus, the stylus pen3has to operate in synchronization with the timing when the touch panel controller10is driven. Therefore, by disposing the sense circuit35, the synchronization signal detector circuit36, and the timing adjuster circuit37in the stylus pen3of the present embodiment, the dedicated synchronization signal that the touch panel controller10drives is detected in the stylus pen3, and the timing of the dedicated synchronization signal of the touch panel controller10is matched to the timing of a pen synchronization signal that is generated by the timing adjuster circuit37of the stylus pen3.

A basic principle of the synchronization of the stylus pen3in the touch panel system1will be described on the basis ofFIG. 5.FIG. 5is a timing chart illustrating the basic principle of synchronization.

The stylus pen3detects the dedicated synchronization signal generated by the timing generator14of the touch panel controller10with the sense circuit35and the synchronization signal detector circuit36. The dedicated synchronization signal is assumed to be a single pulse for simplification.

As illustrated inFIG. 5, it is assumed that a touch panel synchronization signal S0that is the dedicated synchronization signal configured of a single pulse is generated in a constant cycle.

The sense circuit35of the stylus pen3generates a plurality of synchronization signal candidates S1to Sp (p is an integer greater than or equal to two). The synchronization signal candidate Sp illustrated inFIG. 5represents a signal that is delayed by approximately one cycle from the synchronization signal candidate S1. The stylus pen3selects a synchronization signal that has a high degree of matching with the dedicated synchronization signal transmitted from the timing generator14of the touch panel controller10from the synchronization signal candidates S1to Sp and uses the synchronization signal as a synchronization signal for communication with the touch panel controller10. In the example illustrated inFIG. 5, the synchronization signal candidate S4or S5that has a high degree of matching with the touch panel synchronization signal S0is used as the pen synchronization signal of the stylus pen3.

The stylus pen3is in a detection mode until being synchronized, and the drive circuit38is not driven.

According to such a principle, the stylus pen3can synchronize with the dedicated synchronization signal of the touch panel controller10.

(Synchronization Operation of Touch Panel Controller and Stylus Pen of Present Embodiment)

In actuality, synchronization is not easy because noise exists in the reception of the dedicated synchronization signal from the touch panel controller10. Specifically, since a low-frequency component is superimposed on the dedicated synchronization signal, it is difficult to correctly obtain the amplitude of the pulse of the dedicated synchronization signal. As a consequence, a problem arises in that the pulse of the dedicated synchronization signal may not be captured.

An example of a method for resolving such a problem will be described on the basis ofFIG. 6(a)toFIG. 12(c).FIG. 6(a)is a diagram illustrating an output relationship between the drive line of the driver and the sense line of the sense amplifier in the touch panel controller to the touch panel and the stylus pen, andFIG. 6(b)is a waveform diagram illustrating a synchronization waveform and a touch detection waveform.FIG. 7(a)is a waveform diagram illustrating a drive waveform, such as a synchronization waveform and a touch detection waveform transmitted from the touch panel controller to the stylus pen, and a low-frequency noise,FIG. 7(b)is a waveform diagram illustrating a state where the drive waveform and the low-frequency noise are superimposed, andFIG. 7(c)is a waveform diagram illustrating a state where the superimposed waveform is reset at reset timings.FIG. 8is a diagram illustrating a configuration of a reset circuit disposed in the synchronization signal detector circuit of the stylus pen.FIG. 9(a)is a waveform diagram illustrating an example of a synchronization waveform transmitted from the touch panel controller,FIG. 9(b)is a waveform diagram illustrating an input waveform received by the stylus pen,FIG. 9(c)is a waveform diagram illustrating an internal waveform when a reference potential is set at a reset timing R1inFIG. 9(b), andFIG. 9(d)is a waveform diagram illustrating an internal waveform when a reference potential is set at a reset timing R2inFIG. 9(b).FIG. 10(a)is a waveform diagram illustrating a synchronization waveform that uses the M-sequence code “1110010” which is not Manchester-coded, andFIG. 10(b)is a waveform diagram illustrating a synchronization waveform that uses the Manchester-coded M-sequence code “1110010”.FIG. 11(a)is a waveform diagram illustrating an example of a synchronization waveform that has a long High period and is transmitted from the touch panel controller,FIG. 11(b)is a waveform diagram illustrating a reset timing R3of an input waveform received by the stylus pen, andFIG. 11(c)is a waveform diagram illustrating an internal waveform when a reference potential is set at the reset timing R3inFIG. 11(b).FIG. 12(a)is a diagram illustrating a synchronization waveform of a pseudorandom sequence that has periodicity, is Manchester-coded, and is transmitted to the stylus pen from the touch panel controller of the touch panel system, andFIG. 12(b)is a waveform diagram illustrating the synchronization waveform and a touch detection waveform.

In the touch panel system1of the present embodiment, as illustrated inFIG. 6(a), the dedicated synchronization signal of the touch panel controller10is created in the timing generator14of the touch panel controller10and is transmitted by the driver12using the drive lines DL1to DLL. As a mechanism that notifies the stylus pen3of the dedicated synchronization signal which is the drive timing of the touch panel controller10, as illustrated in FIG.6(b), the drive lines DL1to DLLare driven by a waveform that represents synchronization separately from a normal touch detection waveform. Specifically, the touch detection waveform is generated after the synchronization waveform is generated in each of the drive lines DL1to DLL. For easy understanding of description, the touch detection waveform is generated by sequential driving. In addition, representing the generation of the synchronization waveform with a plurality of continuous pulses is to facilitate distinguishing the appearance of the synchronization waveform from the waveform of sequential driving. In actuality, a waveform obtained by Manchester-coding the M-sequence code suggested in the present embodiment or the like is more likely to be detected as a synchronization waveform.

Various types of noise, particularly low-frequency noise, are mixed into the waveform of a signal received by the stylus pen3. InFIG. 7(a), it is assumed that a wide straight line illustrates the dedicated synchronization waveform that is configured of a plurality of dense pulses which the touch panel controller10drives and that a sin curve illustrates noise.

The waveform of the signal received by the stylus pen3is configured of the superimposition of the synchronization waveform obtained from the touch panel controller10and low-frequency noise as illustrated inFIG. 7(b). As a consequence, in the waveform of the signal received by the stylus pen3, the amplitude of low-frequency noise is larger than the amplitude of the synchronization waveform obtained from the touch panel controller10. Thus, when using the waveform of the received signal from the minimum potential to the maximum potential thereof, it is difficult to obtain the synchronization waveform signal because the amplitude of the synchronization waveform signal is a relatively minute amplitude in comparison with the noise.

Therefore, as a method for finding the synchronization waveform from the waveform illustrated inFIG. 7(b)in which the synchronization waveform and low-frequency noise are superimposed, for example, there are a method of removing low-frequency noise with a low frequency cut-off filter and a method of performing a reset operation that sets a reference potential for the waveform in which the synchronization waveform and low-frequency noise are superimposed and obtaining the amplitude of an internal waveform by using the potential difference from the reference potential. However, low frequency cut-off filters are expensive.

In the present embodiment, thus, the stylus pen3that is on the reception side of the synchronization waveform uses the method of performing a reset operation that sets a reference potential for the received input waveform and obtaining the amplitude of an internal waveform by using the potential difference from the reference potential. However, the present invention is not necessarily limited to this. It is also possible to remove noise that is configured of low-frequency components by using a low frequency cut-off filter.

In the present embodiment, the synchronization signal detector circuit36of the stylus pen3is provided with a reset circuit36aillustrated inFIG. 8so as to perform a reset operation that sets a reference potential for the received input waveform. The reset circuit36aresets the superimposed signal waveform illustrated inFIG. 7(b)in which the synchronization waveform obtained from the touch panel controller10and low-frequency noise are superimposed. By resetting the superimposed signal waveform, the superimposed signal waveform returns to the reference potential at a reset timing as illustrated inFIG. 7(c). That is, the reference potential is set to the same potential as the input signal. Then, a positive potential is output when the potential of the superimposed signal waveform input is higher than the reference potential, while a negative potential is output when the potential of the superimposed signal waveform input is lower than the reference potential. Accordingly, it is possible to remove low-frequency components and to keep the amplitude of the signal within a certain range.

When a reset operation that sets a reference potential for the received input waveform is performed on the synchronization waveform that is obtained from the touch panel controller10and that is represented by a sequence of a plurality of equidistant pulses, a problem arises in that it is difficult to identify the dedicated synchronization signal that is the drive timing of the touch panel controller10because pulses are not captured when the reset timing that sets a reference potential for the reception-side stylus pen3overlaps with the pulses of the synchronization waveform.

When, for example, the synchronization waveform illustrated inFIG. 9(a)is transmitted from the touch panel controller10, an input waveform in the reception-side stylus pen3is illustrated by the waveform ofFIG. 9(b). At this time, the internal waveform when the reference potential is set at the reset timing R1in the waveform ofFIG. 9(b)is illustrated inFIG. 9(c). However, when the reset timing R2is set to the second pulse in the waveform ofFIG. 9(b), the internal waveform when the reference potential is set is as illustrated inFIG. 9(d). As a consequence, since the second pulse does not have a positive rise, the second pulse is not captured. That is, it is difficult to identify the dedicated synchronization signal that is the drive timing of the touch panel controller10.

The present embodiment, therefore, uses a constant pattern synchronization signal that is configured of a pseudorandom sequence having periodicity as a synchronization waveform that is transmitted by the touch panel controller10. Specifically, an M-sequence code or a Gold sequence code is used.

The pseudorandom sequence is a code sequence that is used in a pseudorandom signal which is an artificially created random signal. That is, while actual random signals existing in nature are usually called a random signal, artificially created random signals are called a pseudorandom signal. Although a certain rule is necessary since the pseudorandom signal is artificially created, various considerations are made to make the statistical properties of the created signal as close as possible to the statistical properties of the actual random signal. Usually, considerations are made to make the autocorrelation function of the created signal as close as possible to the autocorrelation function δ(t) of white noise. The pseudorandom signal is created by associating a pseudorandom sequence (a sequence of numbers) with physical quantities such as voltage. Types of pseudorandom sequences include a finite length sequence and a periodic sequence. Periodic sequences are widely used in terms of ease of generation and usage. There are an M-sequence and a Gold sequence that represent the periodic sequence.

The autocorrelation of an M-sequence signal and a Gold sequence code shows a very sharp peak and has properties such that the correlation values with others except for the M-sequence signal and the Gold sequence code are very small. The M-sequence and the Gold sequence are sequences that are configured of binary numbers of zero and one and that have periodicity in which binary sequences are connected.

The reliability of determining synchronization is increased by using the M-sequence code or Gold sequence code as a synchronization waveform transmitted by the touch panel controller10even when the reset timing overlaps with one pulse because pulses that match the M-sequence code are determined as a correct synchronization timing.

When, for example, the M-sequence code “1110010” is used as illustrated inFIG. 10(a), the synchronization waveform illustrated inFIG. 10(a)can be obtained by associating “0” with Low of the synchronization waveform and associating “1” with High of the synchronization waveform.

As described above, tolerance to pulses not being captured is increased by using the M-sequence code as a synchronization waveform transmitted by the touch panel controller10and by determining whether pulses match the same M-sequence code in the sense circuit35and the synchronization signal detector circuit36of the stylus pen3. However, when the sequence is long, the sequence includes a pattern in which the number of continuous Highs or Lows is large. Thus, when the reset timing that sets a reference potential is set in this part, an unnecessary potential change occurs to make the determination of a waveform difficult.

For example, an internal waveform when there are High pulses in a long period in the synchronization waveform transmitted by the touch panel controller10as illustrated inFIG. 11(a)and when a reference potential is set at the reset timing R3in the input waveform received by the stylus pen3illustrated inFIG. 11(b)becomes as illustrated inFIG. 11(c), and it is difficult to detect the internal waveform.

Therefore, the present embodiment uses a waveform that is obtained by Manchester-coding a code having good autocorrelation characteristics such as the M-sequence, and the waveform is driven as the synchronization waveform of the touch panel controller10. The Manchester-coded waveform means associating “0” with High→Low of the synchronization waveform and associating “1” with Low→High of the synchronization waveform as illustrated inFIG. 10(b). The opposite may also be possible. Accordingly, as illustrated inFIG. 10(b), it is possible to prevent the occurrence of a case where the period of High or Low is long when the M-sequence code “1110010” is used.

As such, considering the reset operation, it is preferable that the Manchester-coded M-sequence code or Gold sequence code is used.

In the present embodiment, as illustrated inFIG. 12(a), for example, the above 7-bit M-sequence code “1110010” that is Manchester-coded is used to associate pulses as illustrated inFIG. 12(a). Then, the pulses are used as a synchronization waveform of the touch panel controller10as illustrated inFIG. 12(b).

Accordingly, a period of long continuous Highs or Lows does not appear in the synchronization waveform, and it is possible to use a synchronization pattern of which the autocorrelation characteristics facilitate the detection of the synchronization pattern. In addition, since High or Low is continuous at most during a time that represents one bit in the synchronization waveform, it is also possible to adjust the reset timing that sets a reference potential by the reception-side stylus pen3.

For example, when a state where potential is high continues for the time that represents one bit or longer, this is regarded as the influence of noise, and the potential at that point in time is set for a later reference potential. In addition, when the state changes from the high potential close to the reference potential, the potential at that point in time is set for a later reference potential. Accordingly, even when potential significantly decreases due to noise and the like, it is possible to track the potential.

(Continuous Operation of Synchronization of Touch Panel System and Stylus Pen and Touch Position Detection)

Continuous operation of the synchronization of the touch panel system1and the stylus pen3having the above configurations and touch position detection will be described on the basis ofFIG. 13andFIGS. 14(a) to 14(c).FIG. 13is an operation image diagram illustrating a correspondence between a drive operation of the touch panel controller10and a drive operation of the stylus pen3.FIGS. 14(a) to 14(c)are diagrams illustrating a specific drive operation in a synchronization signal detection period, a pause period, and a normal drive period illustrated inFIG. 13.

The drive operation of the stylus pen3, as illustrated inFIG. 13, is configured by repeating three periods of a synchronization signal detection period that is set for detecting the synchronization signal from the touch panel controller10with the sense circuit35and the synchronization signal detector circuit36by turning the operation changing switch34aON and by turning the operation changing switch34bOFF, a preparation period, and a drive mode period during which the drive circuit38drives the pen tip portion31by turning the operation changing switch34aOFF and by turning the operation changing switch34bON.

The synchronization signal detection period is a standby period for detecting a bit pattern that represents the synchronization waveform and is a period during which the synchronization signal pattern is detected from a pen tip signal waveform while the pen tip portion31is not driven. Specifically, in the synchronization signal detection period, as illustrated inFIG. 14(a), each of the drive lines DL1to DLLof the driver12is driven with the same waveform. The pattern of the waveform used includes a pattern that has autocorrelation characteristics such as the M-sequence.

The preparation period illustrated inFIG. 13is a preparation period for selecting a code to drive on the basis of additional information after the detection of the synchronization signal pattern and on the basis of the state of the stylus pen3and for starting to drive the pen tip in accordance with the timing of the touch panel controller10and is a period during which the additional information that includes the timing of starting driving is interpreted.

The drive mode period is a period during which the pen tip portion31is driven by the drive circuit38and is a period during which the pen tip portion31is driven with the selected code while the edge of the drive waveform is finely adjusted in accordance with the drive timing of the touch panel controller10. At this time, the drive circuit38of the stylus pen3is driven in accordance with the drive timing of the touch panel controller10.

Meanwhile, the drive operation of the touch panel controller10is configured by repeating three periods of a period during which the drive lines DL1to DLLare driven with the same waveform, a pause period, and a period during which driving of the drive lines DL1to DLKand driving of the sense lines SL1to SLKto SLLare switched.

The period during which the drive lines DL1to DLLare driven with the same waveform is a period during which the additional information+the synchronization waveform for the synchronization of the stylus pen3are driven. Specifically, as illustrated inFIG. 14(b), the drive lines DL1to DLLare driven with the same waveform.

The pause period is a period during which the stylus pen3ends the detection of synchronization and prepares for driving. Specifically, as illustrated inFIG. 14(b), the pause period is a standby period for disposing a preparation period during which the stylus pen3detects the synchronization waveform and performs normal driving. Thus, the drive waveform during the pause period does not have any meaning and is completely arbitrary. Therefore, driving may not be performed in the pause period. This duration is not necessary when the preparation period on the stylus pen3side is not necessary.

Next, the period during which driving of the drive lines DL1to DLKto DLLand driving of the sense lines SL1to SLKto SLLare switched is a normal drive period for position detection that is performed to obtain data of one face of the touch panel2. Specifically, in the normal drive period, as illustrated inFIG. 14(c), driving of the drive lines DL1to DLKto DLLwith a waveform necessary for detecting the position of a touch of the stylus pen3and sensing are repeated. Methods for driving include sequential driving and parallel driving. InFIG. 14(c), sequential driving is represented so as to facilitate visual understanding of the order of drive patterns.

The stylus pen3, when detecting the synchronization waveform, drives the pen tip portion31with the same waveform as the drive lines DLL+1and DLL+2that correspond to the outside of the touch panel2. InFIG. 14(c), colored backgrounds indicate a sense period, that is, a period during which a charge signal of an electrostatic capacitance for detecting the position of a touch is detected.

(Output Operation of Stylus Pen Outputting Quantitative Characteristic Value Such as Pen Pressure Level)

A mechanism of outputting a quantitative characteristic value such as a pen pressure level in the stylus pen3of the present embodiment will be described on the basis ofFIG. 1,FIG. 15, andFIG. 16.FIG. 15is a diagram illustrating a relationship between a drive pattern of the driver in the touch panel controller and a drive pattern of the drive circuit in the stylus pen.FIG. 16is a diagram illustrating a pen pressure value that is obtained in the stylus pen and a pen pressure value that is represented in the stylus pen having the pen pressure and in the touch panel controller.

As described above, the stylus pen3of the present embodiment is provided with the pen pressure sensor31dand is configured of an electronic pen that outputs a quantitative characteristic value such as a pen pressure level. Thus, in order to transmit a quantitative characteristic value that is detected by the stylus pen3to the touch panel controller10side, the transmission has to use many types of identifiable signals because there are many types of information. As a consequence, a problem arises in that the amount of signals increases, requiring more time for transmission, and the identification of the signal on the reception side becomes complicated.

In the present embodiment, therefore, as illustrated inFIG. 1andFIG. 15, the stylus pen3is configured of an electronic pen that outputs a quantitative characteristic value, and the stylus pen3produces an output that indicates that the quantitative characteristic value in the stylus pen3is increased from the characteristic value of the previous output by using a waveform that corresponds to the drive line DLL+1as the (L+1)-th drive signal line. Meanwhile, the stylus pen3produces an output that indicates that the quantitative characteristic value in the stylus pen3is decreased from the characteristic value which is updated and retained in the previous output by using a waveform that corresponds to the drive line DLL+2as the (L+2)-th drive signal line. Furthermore, in order to determine a next increase or decrease, the result of the current output of an increase or decrease is reflected on the characteristic value that is retained internally. The touch panel controller10is provided with a conversion output unit19that converts and outputs a quantitative characteristic value by using the sum of the initial value of the quantitative characteristic value and the number of outputs×the unit amount of increase or decrease in the waveform that corresponds to the (L+1)-th drive line DLL+1or in the waveform that corresponds to the (L+2)-th drive line DLL+2.

Specifically, as illustrated inFIG. 15, when the stylus pen3detects pen pressure with the pen pressure sensor31dand when the pen pressure value of the pen pressure sensor31dis increased from the value of the previous output, the stylus pen3drives the pen tip portion31with the waveform that corresponds to the drive line DLL+1while the driver12of the touch panel controller10drives the drive lines DL1to DLL. Alternatively, when the stylus pen3detects pen pressure with the pen pressure sensor31dand when the pen pressure value of the pen pressure sensor31dis decreased from the value of the previous output, the stylus pen3drives the pen tip portion31with the waveform that corresponds to the drive line DLL+2while the driver12of the touch panel controller10drives the drive lines DL1to DLL.

Accordingly, by the waveforms that correspond to the drive lines DLL+1and DLL+2, an increasing or decreasing signal of the pen pressure sensor31din the stylus pen3is output, and the signal is detected by the sense lines SL1to SLLthrough the horizontal signal lines HL1to HLKor through the vertical signal lines VL1to VLLthat pass through the position of a touch on the touch panel2at that time.

When the pen pressure value is not transmitted from the stylus pen3yet, the value of the previous output, that is, the characteristic value that is retained internally is set to “0”. For example, at the start of a touch, the previously transmitted value, that is, the characteristic value that is retained internally is “0”.

An interval during which a pen pressure increase or decrease signal of the pen pressure sensor31dis transmitted from the stylus pen3occurs once in a drive period during which the driver12drives the drive lines DL1to DLLonce. While driving performed by sequential driving is illustrated inFIG. 15for easy understanding, driving may be performed by parallel driving.

That is, in the present embodiment, the stylus pen3transmits only two types of information that indicates whether the quantitative characteristic value is increased or decreased from the characteristic value of the previous output. However, by using the two types of information, it is possible to obtain whether the pen pressure value of the pen pressure sensor31dis increased or decreased on the touch panel controller10side.

As illustrated inFIG. 1, the conversion output unit19is disposed in the touch panel controller10. A summation unit19aof the conversion output unit19is configured to convert and output the quantitative characteristic value by using the sum of the initial value of the quantitative characteristic value and the number of outputs×the unit amount of increase or decrease in the waveform that corresponds to the (L+1)-th drive line DLL+1or in the waveform that corresponds to the (L+2)-th drive line DLL+2. A positive value is used for the unit amount of increase or decrease when counting the output of the waveform that corresponds to the (L+1)-th drive line DLL+1. Meanwhile, a negative value is used for the unit amount of increase or decrease when counting the output of the waveform that corresponds to the (L+2)-th drive line DLL+2.

Accordingly, even when a quantitative characteristic value that has many types of information is output, only two types of signals related to increase and decrease are used. Thus, the amount of signals is small, and transmission can be performed in a short amount of time. For example, when the characteristic value is obtained in 10 bits, more time is required because transmission is performed in any form ten times more than one-bit information of increase or decrease. Signal processing in the conversion output unit19of the reception-side touch panel controller10is simplified because it is only necessary to obtain the cumulative value of increase and decrease from the initial value of the quantitative characteristic value.

As a consequence, for example, the pen pressure value illustrated inFIG. 16can be obtained. The pen pressure value data illustrated inFIG. 16starts with an initial value of “0”. It is assumed that the pen pressure value has a value in the range of 0 to 1.0 and that the actual pen pressure value obtained in the pen tip portion31of the stylus pen3is illustrated by a curve inFIG. 16.

As an internal process of the stylus pen3performed on the curve, the pen pressure is represented by a value that changes by 0.2. This internal process is performed by the controller circuit33of the stylus pen3. In the controller circuit33, a determination of whether the internal pen pressure value has to be increased or decreased to approach the pen pressure value of the curve is performed, and the internal pen pressure value is updated on the basis of the determination. The increase or decrease is represented as a drive waveform of the pen tip portion31.

On the touch panel controller10side that receives the increase or decrease information, a pen pressure value change that is the same as the internal pen pressure value of the stylus pen3can be reproduced by the sum of the initial value “0” as a reference and the number of outputs×the unit amount of increase or decrease “0.2” obtained by the conversion output unit19.

Therefore, when the stylus pen3that outputs a quantitative characteristic value such as pen pressure data which has many types of information is used, it is possible to provide the touch panel system1that may transmit the information simply in a short amount of time.

As such, in the touch panel system1of the present embodiment, since the driver12as a synchronization signal transmission unit of the touch panel controller10transmits the synchronization signal to the stylus pen3during synchronization signal transmission periods immediately before each of the first signal line drive period and the second signal line drive period, it is possible to create the synchronization signal by using a drive signal for driving the first signal lines and the second signal lines. Thus, a separate circuit for creating the synchronization signal is not disposed, and the number of components can be reduced. Regarding a typical touch detection drive pattern, the M-sequence may be used in parallel driving. When the M-sequence is also used for the synchronization signal, it is not necessary to dispose a separate circuit. However, a separate circuit is required in sequential driving because it is necessary to generate the synchronization signal. A separate circuit is also required even in parallel driving when driving is performed by using a Hadamard matrix that has orthogonality since the Hadamard matrix is different from the M-sequence of the synchronization signal.

When the synchronization signal is wirelessly transmitted from the touch panel controller10to the stylus pen3, low-frequency signals are superimposed as noise on the synchronization signal. Thus, the synchronization signal may not be captured when noise is not appropriately separated in the case of a single pulse. Meanwhile, in the case of a plurality of unchanging pulses that has the same pitch, it is unclear which part corresponds to the synchronization signal.

Therefore, in the present embodiment, the driver12of the touch panel controller10transmits a synchronization signal having a waveform that is configured of a pseudorandom sequence having periodicity such as the M-sequence code or the Gold sequence code to the stylus pen3during the synchronization signal transmission period, and the stylus pen3is provided with the sense circuit35and the synchronization signal detector circuit36as a synchronization signal detecting unit that detects the synchronization signal.

Thus, the synchronization signal, since being transmitted with a waveform that is configured of a pseudorandom sequence having periodicity, has good autocorrelation characteristics. Thus, accuracy increases in identifying the synchronization signal, and it is possible to reduce the synchronization signal not being captured.

Therefore, it is possible to provide the touch panel system1that can appropriately detect the synchronization signal.

When the synchronization signal on which low-frequency components are superimposed is received and when the reset operation is performed with pulses having a long High period or Low period in the case of detecting the amplitude of the synchronization signal by periodically performing the reset operation to return the received input waveform to the reference potential, potential changes unnecessarily, and it is difficult to determine the waveform.

Therefore, in the present embodiment, the synchronization signal having a waveform configured of a pseudorandom sequence is Manchester-coded. That is, in the Manchester-coding process, a process of associating “0” of the pseudorandom sequence with High→Low of the synchronization waveform and associating “1” with Low→High of the synchronization waveform is performed. The opposite may also be possible. Accordingly, it is possible to prevent the period of High or Low from being lengthened.

In the touch panel system1of the present embodiment, the driver12as a synchronization signal transmission unit of the touch panel controller10doubles as the driver12as a drive unit that supplies a drive signal for driving the horizontal signal lines HL1to HLKas the plurality of first signal lines or the vertical signal lines VL1to VLLas the plurality of second signal lines. The driver12transmits the synchronization signal by changing the drive signal for driving the plurality of horizontal signal lines HL1to HLKor the plurality of vertical signal lines VL1to VLLto a waveform that is configured of a Manchester-coded pseudorandom sequence having periodicity.

Accordingly, since the synchronization signal transmission unit is configured of the driver12that doubles as a drive unit, it is possible to create the synchronization signal by simply changing the waveform pattern of the drive signals of the drive lines DL1to DLLthat are used to drive the horizontal signal lines HL1to HLKand the vertical signal lines VL1to VLL. Thus, a separate circuit for creating the synchronization signal is not disposed, and the number of components can be certainly reduced. As described above, this result is limited to the case where the M-sequence is also used for the synchronization signal in parallel driving.

The touch panel system1of the present embodiment is provided with the stylus pen3as a touch pen, the touch panel2, and the touch panel controller10. The touch panel2has electrostatic capacitances formed at each intersection of the horizontal signal lines HL1to HLKas the K (K is an integer greater than or equal to two) numbers of the first signal lines and the vertical signal lines VL1to VLLas the L (L is an integer satisfying L≧K) numbers of the second signal lines. The touch panel controller10outputs drive signals that drive the K numbers of the horizontal signal lines HL1to HLKor the L numbers of the vertical signal lines VL1to VLLfrom the driver12as a drive unit through the drive lines DL1to DLLas the L numbers of drive signal lines and receives input of detection signals from the K numbers of the horizontal signal lines HL1to HLKor the L numbers of the vertical signal lines VL1to VLLdetected by the sense amplifier13as a detecting unit through the sense lines SL1to SLLas the L numbers of detection signal lines on the basis of a change in charges accumulated in the electrostatic capacitances due to the stylus pen3when the stylus pen3touches the touch panel2.

The stylus pen3is configured of an electronic pen that outputs a quantitative characteristic value, and the stylus pen3produces an output that indicates that the quantitative characteristic value in the stylus pen3is increased from the characteristic value of the previous output by using the waveform that corresponds to the (L+1)-th drive line DLL+1and, meanwhile, produces an output that indicates that the quantitative characteristic value in the stylus pen3is decreased from the characteristic value of the previous output by using a waveform that corresponds to the (L+2)-th drive line DLL+2. The touch panel controller10is provided with the conversion output unit19that converts and outputs a quantitative characteristic value by using the sum of the initial value of the quantitative characteristic value and the number of outputs×the unit amount of increase or decrease in the waveform that corresponds to the (L+1)-th drive line DLL+1or in the waveform that corresponds to the (L+2)-th drive line DLL+2.

Accordingly, since only two types of signals related to increase and decrease are used even when a quantitative characteristic value that has many types of information is output, the amount of signals is small, and transmission can be performed in a short amount of time. In addition, signal processing on the reception side is simplified because it is only necessary to obtain the cumulative value of increase and decrease from the initial value of the quantitative characteristic value.

Therefore, when the stylus pen3that outputs a quantitative characteristic value which has many types of information is used, it is possible to provide the touch panel system1that may transmit the information simply in a short amount of time.

In the touch panel system1of the present embodiment, the stylus pen3as an electronic pen is provided with the pen pressure sensor31d. Accordingly, it is possible to detect a pen pressure level that is a quantitative characteristic value when the stylus pen3touches the touch panel2.

The present invention is not limited to the above embodiment. Various modifications can be carried out within the scope of the present invention. For example, while the pen pressure level of the pen pressure sensor31dis used as an example of a quantitative characteristic value in the embodiment, the present invention is not particularly limited to this.

As an example of a quantitative characteristic value, for example, a shade level can also be used as a quantitative characteristic value when, for example, a colored character is displayed by the stylus pen3.

Second Embodiment

Another embodiment of the present invention will be described as follows on the basis ofFIG. 17toFIG. 20. Configurations other than those described in the present embodiment are the same as those of the first embodiment. For convenience of description, members having the same function as the members illustrated in the drawings of the first embodiment will be designated by the same reference sign, and descriptions thereof will be omitted.

The touch panel system1of the present embodiment is different in that the conversion output unit19of the touch panel controller10can change the unit amount of increase or decrease.

A configuration of the touch panel system1of the present embodiment will be described on the basis ofFIG. 17.FIG. 17is a block diagram illustrating the configuration of the touch panel system1of the present embodiment.

In the touch panel system1of the present embodiment, as illustrated inFIG. 17, a unit increase or decrease amount changing unit19bthat changes the unit amount of increase or decrease is disposed in the conversion output unit19.

When, for example, the quantitative characteristic value of the stylus pen3is generated in a short amount of time, a difference occurs between the quantitative characteristic value and the actual quantitative characteristic value of the stylus pen3if the unit amount of increase or decrease is not increased.

In the present embodiment, therefore, the unit increase or decrease amount changing unit19bis disposed in the conversion output unit19, and the unit amount of increase or decrease is changed by the unit increase or decrease amount changing unit19b. Accordingly, it is possible to suppress the occurrence of a difference between the quantitative characteristic value and the actual quantitative characteristic value of the stylus pen3.

What can be detected by the conversion output unit19is only the number of outputs in a certain amount of time in the waveform that corresponds to the (L+1)-th drive line DLL+1or in the waveform that corresponds to the (L+2)-th drive line DLL+2. Therefore, the problem is how the unit increase or decrease amount changing unit19bdetermines whether to change the unit amount of increase or decrease.

In the present embodiment, therefore, as illustrated inFIG. 17, a continuous increase or decrease changing unit19cis disposed in the unit increase or decrease amount changing unit19b. The continuous increase or decrease changing unit19cis configured to increase or decrease the unit amount of increase or decrease from the previous value when the number of continuous outputs in each of the waveform that corresponds to the (L+1)-th drive line DLL+1and the waveform that corresponds to the (L+2)-th drive line DLL+2is P (P is an integer greater than or equal to two).

That is, for example, when the number of continuous outputs in the waveform that corresponds to the (L+1)-th drive line DLL+1is P (P is an integer greater than or equal to two), it is determined that a rapid change occurs, and the unit amount of increase or decrease is, for example, doubled. When increase further continues, the unit amount of increase or decrease is further increased.

Specifically, for example, as illustrated inFIG. 18, when the internal pen pressure value of the stylus pen3is represented by changing the unit amount of increase or decrease by 0.1, there may be a case where the internal pen pressure value cannot sufficiently keep up with the speed of change even in the case of the same amount of a pen pressure change.

In the present embodiment, therefore, as illustrated inFIG. 19, the unit amount of increase or decrease is increased from 0.1 to 0.2 when the pen pressure value is continuously increased or decreased twice. When the pen pressure value is further increased or decreased once more, the unit amount of increase or decrease is further increased to 0.3.

Meanwhile, when increase or decrease does not continue, the unit amount of increase or decrease is decreased. When increase and decrease are continuously repeated, the unit amount of increase or decrease is further decreased. As such, for example, the next unit amount of increase or decrease is increased when increase or decrease continues twice, or otherwise, the next unit amount of increase or decrease is decreased.

The unit amount of increase or decrease is increased or decreased by 0.1. However, the range of increase or decrease of the unit amount of increase or decrease is greater than or equal to 0.1 and less than or equal to 0.3.

While the pen pressure value is reproduced by disposing the unit increase or decrease amount changing unit19bin the touch panel controller10in the present embodiment, it is also possible that the pen pressure is transmitted to the touch panel controller10side by disposing the unit increase or decrease amount changing unit19band the continuous increase or decrease changing unit19con the stylus pen3side. Accordingly, in the conversion output unit19of the touch panel controller10, if an increase or decrease in the pen pressure value is obtained, the unit amount of increase or decrease can be set to the same state as the range of change in the stylus pen3by finding how many times an increase or decrease in the pen pressure value continues, and the same pen pressure as the internal pen pressure value of the stylus pen3can be reproduced by using the range of change and the increase or decrease information.

In the case of outputting the internal pen pressure value of the stylus pen3, for example, as illustrated inFIG. 18, when the internal pen pressure value of the stylus pen3is represented by changing the unit amount of increase or decrease by 0.1, it is possible to perform the following process when the internal pen pressure value cannot sufficiently keep up with the speed of change even in the case of the same amount of a pen pressure change.

That is, as illustrated inFIG. 20, the interval between determinations is reduced in half while the range of increase or decrease of the unit amount of increase or decrease is maintained to 0.1. Accordingly, since the speed of change of pen pressure relatively decreases when the interval between determinations is short, the representation of the internal pen pressure value is not delayed.

Third Embodiment

Another embodiment of the present invention will be described as follows on the basis ofFIG. 21toFIG. 26. Configurations other than those described in the present embodiment are the same as those of the first embodiment. For convenience of description, members having the same function as the members illustrated in the drawings of the first embodiment will be designated by the same reference sign, and descriptions thereof will be omitted.

(Synchronization Operation of Touch Panel Controller and Stylus Pen of Present Embodiment)

In the present embodiment, synchronization of the stylus pen3and, furthermore, a method that may prevent the pulses of the dedicated synchronization signal from not being captured will be described on the basis ofFIG. 21(a)toFIG. 25(c).FIG. 21(a)is a waveform diagram illustrating an input waveform of a synchronization signal received by the stylus pen in the touch panel system of the present embodiment, andFIG. 21(b)is a waveform diagram illustrating an internal waveform when a reference potential is set at reset timings R1to R6.FIG. 22(a)is a waveform diagram illustrating an example of a synchronization waveform transmitted from the touch panel controller,FIG. 22(b)is a waveform diagram illustrating reset timings R7, R8, and R9of an input waveform received by the stylus pen, andFIG. 22(c)is a waveform diagram illustrating a synchronization waveform when a reference potential is set at the reset timings R7, R8, and R9illustrated inFIG. 22(b).FIG. 23is a timing chart illustrating output waveforms of the touch panel controller in which a fixing period is disposed immediately before a synchronization waveform is output.FIG. 24(a)is a waveform diagram illustrating an example of a synchronization waveform transmitted from the touch panel controller,FIG. 24(b)is a waveform diagram illustrating reset timings R11, R12, and R13of an input waveform received by the stylus pen, andFIG. 24(c)is a waveform diagram illustrating a synchronization waveform when a reference potential is set at the reset timings R11, R12, and R13illustrated inFIG. 24(b).FIG. 25(a)is a diagram illustrating a method for transmitting a synchronization waveform that is transmitted by drive lines DL1to DLLof the driver in the touch panel controller,FIG. 25(b)is a waveform diagram illustrating an input waveform received by the stylus pen, andFIG. 25(c)is a waveform diagram illustrating a synchronization waveform when a reference potential is set after the input waveform is initially reset in the fixing period illustrated inFIG. 25(b).

When the reset operation is performed at the reset timings R1to R6where a reference potential is set in a case where the input waveform illustrated inFIG. 21(a)is obtained in the stylus pen3, the internal waveform illustrated inFIG. 21(b)is obtained.

In this case, even when the Manchester-coded M-sequence code is used, as illustrated inFIGS. 22(a) to 22(c), the same signal has different potentials depending on the timing of the reset operation that sets a reference potential, and the difficulty of identifying whether the synchronization waveform output of the touch panel controller10is High or Low remains the same. That is, it is difficult to find whether a second peak is High or Low.

Therefore, in the present embodiment, as illustrated inFIG. 23, a fixing period F is disposed immediately before the output of the synchronization waveform to fix the output waveform of the touch panel controller10. The time of fixing is set to a time in which the timing of the reset operation that sets a reference potential in the reception-side stylus pen3is included at least once.

Accordingly, a stable potential can be set as a reference potential before the synchronization waveform is output.

Specifically, as illustrated inFIGS. 24(a) and 24(b), the reset timings R11, R12, and R13are disposed in the fixing period F to set a reference potential. Accordingly, as illustrated inFIG. 24(c), the identification of whether the output of the touch panel controller10is High or Low is facilitated when the synchronization waveform is detected.

As a consequence, as illustrated inFIG. 23, the potential when the reset operation ends becomes a reference potential by disposing the fixing period F before the synchronization waveform is output. Thus, as illustrated inFIGS. 25(a) to 25(c), by disposing the fixing period F that is longer than the interval between the reset operations in the stylus pen3, the reset operation is certainly performed once or more prior to the synchronization signal detection period in a state where the drive potential of the touch panel controller10is set, and the waveform can be shaped in a stable state from the start of the synchronization signal detection period.

(Continuous Operation of Synchronization of Touch Panel System and Stylus Pen and Touch Position Detection)

Continuous operation of the synchronization of the touch panel system1and the stylus pen3having the above configurations and touch position detection will be described on the basis ofFIG. 26andFIG. 27.FIG. 26is an operation image diagram illustrating a correspondence between a drive operation of the touch panel controller10and a drive operation of the stylus pen3.FIG. 27is a diagram illustrating a specific drive operation in the fixing period illustrated inFIG. 26. In the description ofFIG. 26andFIG. 27, the same part asFIG. 13andFIGS. 14(a) to 14(c)of the first embodiment will be briefly described.

The stylus pen3, as illustrated inFIG. 26, includes the synchronization signal detection period for detecting the synchronization signal from the touch panel controller10with the sense circuit35and the synchronization signal detector circuit36, the preparation period, and the drive mode period during which the pen tip portion31is driven by the drive circuit38.

The synchronization signal detection period, the preparation period, and the drive mode period are the same as those described inFIG. 13andFIGS. 14(a) to 14(c).

Meanwhile, the touch panel controller10includes the fixing period F, the period during which the drive lines DL1to DLLare driven with the same waveform, the pause period, and a period during which the drive lines DL1to DLLare driven and during which a change in charges of the electrostatic capacitances is read by the sense lines SL1to SLL.

The fixing period F is a period for stabilizing a signal level with which the stylus pen3detects synchronization. Specifically, in the fixing period F, as illustrated inFIG. 21, the drive lines DL1to DLLare fixed to either Low or High. Although any of Low and High is favorable, the drive lines DL1to DLLare fixed to Low in the present embodiment. Thus, the drive lines DL1to DLLof the touch panel controller10have zero potentials. At this time, the drive line DLL+1for the pen pressure sensor31dof the stylus pen3is not driven.

The period during which the drive lines DL1to DLLare driven with the same waveform is a period during which the additional information+the synchronization waveform for the synchronization of the stylus pen3are driven. Specifically, as illustrated inFIG. 14(b), the drive lines DL1to DLLare driven with the same waveform.

The pause period is a period during which the stylus pen3ends the detection of synchronization and prepares for driving. Specifically, as illustrated inFIG. 14(b), the pause period is a standby period for disposing a preparation period during which the stylus pen3detects the synchronization waveform and performs normal driving. Thus, the drive waveform during the pause period does not have any meaning and is completely arbitrary. Therefore, driving may not be performed in the pause period. In addition, the stylus pen3does not drive the pen tip portion31with the waveforms that correspond to the drive lines DLL+1and DLL+2. This duration is not necessary when the preparation period on the stylus pen3side is not necessary.

Next, the period during which the drive lines DL1to DLLare driven and during which a change in charges of the electrostatic capacitances is read by the sense lines SL1to SLLis a normal drive period for position detection that is performed to obtain data of one face of the touch panel2. Specifically, in the normal drive period, as illustrated inFIG. 14(c), driving of the drive lines DL1to DLLand reading from the sense lines SL1to SLLare repeated. Methods for driving include sequential driving and parallel driving. InFIG. 14(c), sequential driving is represented so as to facilitate visual understanding of the order of drive patterns.

The stylus pen3, when detecting the synchronization waveform, drives the pen tip portion31with the waveforms that correspond to the drive lines DLL+1and DLL+2which correspond to the outside of the touch panel2. That is, the stylus pen3outputs waveforms that correspond to the drive lines DLL+1and DLL+2in accordance with driving of the drive lines DL1to DLLby the touch panel controller10. InFIG. 14(c), colored backgrounds indicate a sense period, that is, a period during which a charge signal of an electrostatic capacitance is detected.

As such, in the touch panel system1of the present embodiment, the sense circuit35and the synchronization signal detector circuit36as a synchronization signal detecting unit of the stylus pen3as an electronic pen detect the amplitude of the synchronization signal by periodically performing the reset operation to return the received input waveform to the reference potential when the synchronization signal on which low-frequency components are superimposed is received. Accordingly, it is possible to detect the amplitude of the synchronization signal inexpensively without using an expensive low frequency cut-off filter for the removal of low-frequency components superimposed as noise.

When the reset operation overlaps with a High part of a pulse while the reset operation is arbitrarily performed on the received input waveform, the subsequent signal waveform becomes negative, and thus the positive High part of the pulse cannot be recognized correctly. As a consequence, the synchronization signal may not be captured.

Therefore, in the present embodiment, the synchronization signal transmission period is configured of the fixing period F during which a fixed synchronization signal of which the waveform is fixed to High or Low is transmitted and a pseudorandom sequence waveform period during which the synchronization signal of which the waveform is configured of a pseudorandom sequence having periodicity such as the M-sequence code or the Gold sequence code is transmitted. In the fixing period F, the reset operation is performed at least once.

Accordingly, since the input waveform returns to the reference potential in the fixing period F during which the waveform is fixed to High or Low, it is possible to appropriately determine whether the subsequent pulse is High or Low.

Fourth Embodiment

Still another embodiment of the present invention will be described as follows on the basis ofFIG. 28. Configurations other than those described in the present embodiment are the same as those of the first embodiment and the second embodiment. For convenience of description, members having the same function as the members illustrated in the drawings of the first embodiment and the second embodiment will be designated by the same reference sign, and descriptions thereof will be omitted.

In the present embodiment, a case where the touch panel system1is mounted on a mobile phone as an electronic device will be described on the basis ofFIG. 28.FIG. 28is a block diagram illustrating a configuration of the mobile phone.

A mobile phone60of the present embodiment, as illustrated inFIG. 28, is provided with the touch panel system1, a display panel61, an operating key62, a loudspeaker63, a microphone64, a camera65, a CPU66, a ROM67, a RAM68, and a display controller circuit69. The constituent elements are connected to each other by a data bus.

The touch panel system1, as described above, includes the touch panel2, the touch panel controller10that detects an electrostatic capacitance or an electrostatic capacitance difference, and the stylus pen3.

The display panel61uses the display controller circuit69to display an image stored on the ROM67and the RAM68. In addition, the display panel61either overlies the touch panel2or incorporates the touch panel2. It is also possible to cause a touch recognition signal that indicates the position of a touch on the touch panel2and that is generated by the touch recognizing unit17to play the same role as a signal that indicates that the operating key62is operated.

The operating key62receives an instruction that is input by a user of the mobile phone60.

The loudspeaker63outputs sound that is based on, for example, music data stored on the RAM68.

The microphone64receives input of the voice of the user. The mobile phone60digitizes the input voice (analog data). Then, the mobile phone60transmits the digitized voice to a communication opponent (for example, other mobile phones).

The camera65captures an image of a subject in response to the user operating the operating key62. The captured image data of the subject is stored on the RAM68or an external memory (for example, a memory card).

The CPU66controls the operation of the touch panel system1and the mobile phone60. The CPU66, for example, executes programs stored on the ROM67.

The ROM67stores data in a non-volatile manner. In addition, the ROM67is a ROM such as an erasable programmable read-only memory (EPROM) or a flash memory on which data can be written and deleted. Although illustration is not provided inFIG. 28, the mobile phone60may be configured to be provided with an interface (IF) for wired connection to other electronic devices.

The RAM68stores data that is generated by the CPU66executing a program or data that is input through the operating key62in a volatile manner.

As such, the mobile phone60as an electronic device in the present embodiment is provided with the touch panel system1. Accordingly, it is possible to provide the mobile phone60as an electronic device that is provided with the touch panel system1which can appropriately detect the synchronization signal.

CONCLUSION

In order to resolve the above problem, the touch panel system1in a first aspect of the present invention includes a touch pen (stylus pen3), the touch panel2that has electrostatic capacitances formed at each intersection of the K (K is an integer greater than or equal to two) numbers of the first signal lines (horizontal signal lines HL1to HLK) and the L (L is an integer satisfying L≧K) numbers of the second signal lines (vertical signal lines VL1to VLL), and the touch panel controller10. In the touch panel system1, the touch panel controller10outputs drive signals that drive the K numbers of the first signal lines (horizontal signal lines HL1to HLK) or the L numbers of the second signal lines (vertical signal lines VL1to VLL) from a drive unit (driver12) through L numbers of drive signal lines (drive lines DL1to DLL) and receives input of detection signals from the K numbers of the first signal lines (horizontal signal lines HL1to HLK) or the L numbers of the second signal lines (vertical signal lines VL1to VLL) detected by a detecting unit (sense amplifier13) through L numbers of detection signal lines (sense lines SL1to SLL) on the basis of a change in charges accumulated in the electrostatic capacitances due to the touch pen (stylus pen3) when the touch pen (stylus pen3) touches the touch panel2. The touch pen (stylus pen3) is configured of an electronic pen that outputs a quantitative characteristic value. The electronic pen (stylus pen3) produces output that indicates that the quantitative characteristic value of the electronic pen (stylus pen3) is increased from the characteristic value of the previous output by using the waveform that corresponds to an (L+1)-th drive signal line (drive line DLL+1) other than the L numbers of the drive signal lines (drive lines DL1to DLL) and, meanwhile, produces output that indicates that the quantitative characteristic value of the electronic pen (stylus pen3) is decreased from the characteristic value of the previous output by using the waveform that corresponds to an (L+2)-th drive signal line (drive line DLL+2) other than the L numbers of the drive signal lines (drive lines DL1to DLL). The touch panel controller10includes the conversion output unit19that converts and outputs the quantitative characteristic value by using the sum of the initial value of the quantitative characteristic value and the number of outputs×the unit amount of increase or decrease in the waveform which corresponds to the (L+1)-th drive signal line (drive line DLL+1) or in the waveform which corresponds to the (L+2)-th drive signal line (drive line DLL+2). The representation of L+1 and L+2 is for representing drive signal lines other than the L numbers or the K numbers of drive signal lines, meaning that the drive signals are not actually connected to the touch panel. Thus, when the actual number of connection lines between the touch panel and the touch panel controller is less than L or K, a waveform that corresponds to an arbitrary drive signal line of the non-connected drive signal lines may be used.

According to the above configuration, the touch pen is configured of an electronic pen that outputs a quantitative characteristic value such as a pen pressure level.

In the present invention, the electronic pen produces output that indicates that the quantitative characteristic value of the electronic pen is increased from the characteristic value of the previous output by using the waveform that corresponds to the (L+1)-th drive signal line and, meanwhile, produces output that indicates that the quantitative characteristic value of the electronic pen is decreased from the characteristic value of the previous output by using the waveform that corresponds to the (L+2)-th drive signal line. The touch panel controller is provided with the conversion output unit that converts and outputs the quantitative characteristic value by using the sum of the initial value of the quantitative characteristic value and the number of output×the unit amount of increase or decrease in the waveform that corresponds to the (L+1)-th drive signal line or in the waveform that corresponds to the (L+2)-th drive signal line.

That is, in the present invention, the electronic pen outputs only two types of information that indicates whether the quantitative characteristic value is increased or decreased from the characteristic value of the previous output.

The conversion output unit is disposed in the touch panel controller. The conversion output unit converts and outputs a quantitative characteristic value by using the sum of the initial value of the quantitative characteristic value and the number of outputs×the unit amount of increase or decrease in the waveform that corresponds to the (L+1)-th drive signal line or in the waveform that corresponds to the (L+2)-th drive signal line.

Accordingly, since only two types of signals related to increase and decrease are used even when a quantitative characteristic value that has many types of information is output, the amount of signals is small, and transmission can be performed in a short amount of time. In addition, signal processing on the reception side is simplified because it is only necessary to obtain the cumulative value of increase and decrease from the initial value of the quantitative characteristic value.

Therefore, when the electronic pen that outputs a quantitative characteristic value which has many types of information is used, it is possible to provide the touch panel system that may transmit the information simply in a short amount of time.

In the touch panel system1in a second aspect of the present invention, the conversion output unit19in the touch panel system1of the first aspect preferably includes the unit increase or decrease amount changing unit19bthat changes the unit amount of increase or decrease.

When, for example, the quantitative characteristic value of the electronic pen is generated in a short amount of time, a difference occurs between the quantitative characteristic value and the actual quantitative characteristic value of the electronic pen if the unit amount of increase or decrease is not increased.

Regarding this point, in the present invention, since the conversion output unit is provided with the unit increase or decrease amount changing unit that changes the unit amount of increase or decrease, the unit increase or decrease amount changing unit can change the unit amount of increase or decrease.

Therefore, it is possible to suppress the occurrence of a difference between the quantitative characteristic value and the actual quantitative characteristic value of the electronic pen.

In the touch panel system1in a third aspect of the present invention, the unit increase or decrease amount changing unit19bin the touch panel system1of the second aspect preferably includes the continuous increase or decrease changing unit19cthat increases or decreases the unit amount of increase or decrease when the continuous number of outputs in each of the waveform that corresponds to the (L+1)-th drive signal line (drive line DLL+1) and the waveform that corresponds to the (L+2)-th drive signal line (drive line DLL+2) is P (P is an integer greater than or equal to two).

What can be detected by the conversion output unit is only the number of outputs in a certain amount of time in the waveform that corresponds to the (L+1)-th drive signal line or in the waveform that corresponds to the (L+2)-th drive signal line. Therefore, the problem is how the unit increase or decrease amount changing unit determines whether to change the unit amount of increase or decrease.

Regarding this point, in the present invention, the continuous increase or decrease changing unit is disposed in the unit increase or decrease amount changing unit to increase or decrease the unit amount of increase or decrease when the continuous number of outputs in each of the waveform that corresponds to the (L+1)-th drive signal line and the waveform that corresponds to the (L+2)-th drive signal line is P (P is an integer greater than or equal to two).

That is, for example, when the number of continuous outputs in the waveform that corresponds to the (L+1)-th drive signal line is P (P is an integer greater than or equal to two), it is determined that a rapid change occurs, and the unit amount of increase or decrease is, for example, doubled. In addition, when, for example, increase further continues, the unit amount of increase or decrease can be further increased.

Accordingly, since the unit amount of increase or decrease can be increased even if the quantitative characteristic value of the electronic pen is generated in a short amount of time, it is possible to suppress the occurrence of a difference between the quantitative characteristic value and the actual quantitative characteristic value of the electronic pen.

In the touch panel system1in a fourth aspect of the present invention, the electronic pen in the touch panel system1of any one of the first to third aspects can include the pen pressure sensor31d.

Accordingly, it is possible to detect the pen pressure information that is an example of a quantitative characteristic value when the electronic pen touches the touch panel.

An electronic device (mobile phone60) in a fifth aspect of the present invention is provided with the touch panel system1of any one of the first to fourth aspects.

According to the invention, it is possible to provide the electronic device that is provided with the touch panel system which may transmit information simply in a short amount of time when the electronic pen that outputs a quantitative characteristic value which has many types of information is used.

The present invention is not limited to each embodiment described above. Various modifications can be carried out within the scope of the claims. In addition, an embodiment that is obtained by appropriately combining technical means disclosed in each different embodiment is also included in the technical scope of the present invention.

INDUSTRIAL APPLICABILITY

The present invention can be used in a touch panel system and an electronic device that detect the position of a touch of a touch pen on a touch panel which has electrostatic capacitances formed at each intersection of a plurality of first signal lines and a plurality of second signal lines and as an electronic device, for example, can be used in a mobile phone.

REFERENCE SIGNS LIST