WO2016002372A1 - Touch panel controller, touch panel system, and electronic device - Google Patents

Abstract

The objectives of the present invention are to synchronize the drive timing of a stylus pen, to improve the precision with which a touch is detected, to reduce erroneous operations caused by electromagnetic interference waves, and to reduce power consumption. A drive line driving circuit (15) outputs a synchronization signal during a synchronization period and outputs a detection signal during a touch and pen input detection period. A driving performance control unit (21) sets the driving performance of the drive line driving circuit (15) for the synchronization period and the driving performance of the drive line driving circuit (15) for the touch and pen input detection period.

Description

Touch panel controller, touch panel system, and electronic device

The present invention relates to a touch panel controller, a touch panel system, and an electronic device for driving a touch panel having capacitances respectively formed at intersections of a plurality of first signal lines and a plurality of second signal lines.

In recent years, touch panels have become indispensable as input means to electronic devices. From relatively large devices such as televisions, monitors and white boards to relatively small devices such as smartphones and tablet terminals, touch panels are generally used as input means.

In addition to the information related to the touch position, it also has a dedicated touch pen capable of giving additional information (for example, information such as the state of whether or not the button is pressed and the writing pressure), A number of touch panel systems have also been proposed, which can perform input with a touch pen and can realize more accurate and more diverse inputs.

For example, Patent Document 1 discloses a touch panel system that can accurately detect each touch position even when touch operations with a plurality of electronic pens and fingers are simultaneously performed.

The touch panel system disclosed in Patent Document 1 includes a plurality of transmission electrodes (first signal lines) to which a drive unit and a pen synchronization signal are applied by a transmission unit, and a plurality of reception electrodes (second signal lines) that output response signals to a reception unit. ), An electronic pen (touch pen), and a control unit. The electronic pen sends a pen identification signal to the reception electrode in response to detection of the pen synchronization signal of the transmission electrode, and the control unit controls the drive timing at which the transmission unit applies the drive signal and the pen synchronization signal to the transmission electrode At the same time, the touch position is detected based on the detection data output from the receiving unit.

According to the above configuration, it is possible to synchronize the drive timing of the electronic pen and the drive timing at which the control unit drives the transmission electrode, and to discriminate the pointing object that has performed the touch operation based on the pen identification signal. it can. Thereby, it is possible to simultaneously detect the touch operation by the finger and the touch operation via the electronic pen.

Japanese Patent Publication "Japanese Patent Application Laid-Open Publication No. 2012-22543 (released on February 2, 2012)"

In order for the electronic pen to properly detect the pen synchronization signal, it is necessary to sufficiently increase the drivability of the transmission unit and to shorten the delay (time constant) of rising and falling of the waveform of the pen synchronization signal. Similarly, in order for the control unit to accurately detect the touch position, it is necessary to sufficiently increase the drive capability of the transmission unit and to shorten the time constants of the rise and fall of the drive signal.

However, by increasing the drive capability of the control unit, the current flowing to the transmission electrode is increased, resulting in problems such as increased power consumption and erroneous operation due to the generation of electromagnetic interference waves. Therefore, there is a trade-off between synchronization signal detection performance and touch position detection accuracy, and reduction in power consumption and malfunction, so as to suppress the generation of electromagnetic interference waves while ensuring the required signal detection performance. It is preferable to optimize the drive capability of the control unit.

Here, a time constant allowed for the waveform of the pen synchronization signal when the electronic pen detects the pen synchronization signal, and a time constant allowed for the waveform of the drive signal when the control unit accurately detects the touch position Are different from each other. That is, the optimum driving capability of the circuit that generates the pen synchronization signal and the optimum driving capability of the circuit that generates the driving signal are different from each other. Therefore, when generating a pen synchronization signal and a drive signal in one circuit, the prior art can not optimize the drive capability of the circuit in accordance with each signal.

In the touch panel system of Patent Document 1, the pen synchronization signal is generated based on the pulse generated by the pen synchronization pulse generation unit, and the drive signal is generated based on the pulse generated by the position detection pulse generation unit. However, Patent Document 1 does not consider the driving capabilities of the pen synchronization pulse generation unit and the position detection pulse generation unit. Therefore, the driving capabilities of the pen synchronization pulse generation unit and the position detection pulse generation unit are not optimized. As a result, problems such as a shift between the drive timing of the electronic pen and the drive timing of the control unit, a decrease in touch position detection accuracy, an occurrence of malfunction due to an electromagnetic interference wave, and an increase in power consumption may occur.

The present invention has been made in view of the above problems, and its object is to optimize the drive capability of the control unit to synchronize the drive timing of the electronic pen with the drive timing of the control unit, and to detect the touch. An object of the present invention is to provide a touch panel controller, a touch panel system, and an electronic device capable of realizing improvement in accuracy and malfunction and reduction in power consumption due to electromagnetic interference waves.

In order to solve the above problems, a touch panel controller according to an aspect of the present invention drives a touch panel having a plurality of first signal lines and a plurality of second signal lines intersecting the plurality of first signal lines. A touch panel controller, and includes a drive circuit for outputting a signal to the first signal line, and a drive capability control unit for controlling the drive capability of the drive circuit, wherein the drive circuit operates in a first period. Outputting a synchronization signal for synchronizing the drive timing of the touch pen capable of giving an input operation to the touch panel to the operation of the drive circuit to the first signal line, and the second period different from the first period During the first period, the detection signal for detecting the input operation to the touch panel is output to the first signal line, and the drive capability control unit outputs the detection signal during the first period. It takes the drive capability of the drive circuit, and sets the driving capability of the driving circuit in the second period.

According to one aspect of the present invention, by optimizing the drive capability of the control unit, synchronization between the drive timing of the electronic pen and the drive timing of the control unit, improvement in touch detection accuracy, and malfunction due to electromagnetic interference waves And reduction of power consumption can be realized.

It is a block diagram which shows schematic structure of the touch panel system which concerns on Embodiment 1 of this invention. FIG. 8 is a diagram showing an example of signal waveforms output from the touch panel controller to drive lines D ₀ to D _n and a signal waveform corresponding to drive line D _{n + 1} driven by the pen in the touch panel system. It is a figure which shows the schematic circuit structure of the touch panel with which the touch panel system was equipped. It is a figure which shows schematic structure of the stylus pen with which the touch-panel system was equipped. It is a figure which shows schematic structure of the touch-panel controller with which the touch-panel system was equipped. It is a figure which shows the correspondence of the magnitude | size of the touch reaction detected by the touch-panel controller, and the magnitude | size of the amplitude of the synchronous waveform detected inside the stylus pen. It is a figure which shows how to determine a drive capacity setting value, (a) is a figure which shows how to determine the drive capacity setting value in a synchronous period, (b) is a figure which shows how to determine the drive capacity setting value in a data transmission period. It is. It is a figure which shows how to determine the driving capability setting value in a touch and pen input detection period. It is a figure which shows schematic structure of the touch-panel controller with which the touch-panel system which concerns on Embodiment 2 of this invention was equipped. It is a figure which shows schematic structure of the multiplexer with which the touch panel system was equipped. It is a functional block diagram which shows the structure of the mobile telephone which concerns on Embodiment 3 of this invention.

Embodiment 1
Hereinafter, the touch panel system according to the first embodiment of the present invention will be described in detail based on FIGS. 1 to 8.

<Configuration of touch panel system>
FIG. 1 is a block diagram showing a schematic configuration of the touch panel system 1 of the present embodiment.

As illustrated, the touch panel system 1 includes a touch panel 2, a stylus pen 3 (touch pen), and a touch panel controller 4 for driving the touch panel 2 and the stylus pen 3.

Although not illustrated, the touch panel 2 is provided with a plurality (n) of drive lines D ₀ to D _n extending in the horizontal direction in the drawing in parallel, and sense lines S ₀ extending in the vertical direction in the drawing. A plurality (m) of parallel to S _m are provided in parallel. The electrostatic capacitance (not shown) is formed at the intersections of the drive lines D ₀ to D _n (first signal lines) and the sense lines S ₀ to S _m (second signal lines). Is provided. The m and n may be the same or different.

As described above, the description is given on the assumption that the touch panel 2 is a capacitive touch panel, but the present invention is not limited to the capacitive touch panel. The present invention relates to a touch panel of another type capable of reading signal values from sensors provided on the touch panel in a matrix (for example, a resistive film type capable of reading a plurality of electric resistance values distributed in a matrix) May be applied to the touch panel of

In the present embodiment, the stylus pen 3 drives the pen tip of the stylus pen 3 with the same waveform as the touch panel controller 4 drives the drive line D _{n + 1} , and the capacitance on the touch surface of the touch panel 2 is The change of the capacitance is detected through each of the sense lines S ₀ to S _m , and the state of whether the button provided on the stylus pen 3 is pressed by the user, the addition of writing pressure, etc. The touch panel controller 4 is configured to detect dynamic information. In addition, the waveform for driving the pen tip may not necessarily be D _{n +1} , such as D _{n +2} , if it is a waveform used for other than the drive line connected to the sensor. For example, when driving a sensor with drive lines D ₀ to D _{n + 1} , the pen tip may be driven with a waveform corresponding to D ₀ , or the pen tip may be driven with a waveform of D _{n +2} or later.

Then, the distance between the touch panel 2 and the stylus pen 3 can be calculated by the touch panel controller 4 from the change in the capacitance due to the touch.

FIG. 2 is a diagram showing signal waveforms outputted from the touch panel controller 4 to the drive lines D ₀ to D _n and a signal waveform D _{n + 1} for driving the pen tip of the stylus pen 3.

The touch panel controller 4 outputs a reception preparation signal to each drive line D ₀ to D _n during a reception preparation period (fourth period), and outputs a synchronization signal during a subsequent synchronization period (first period). The data transmission signal is output during the subsequent data transmission period (third period), and the drive signal (detection signal) is output during the subsequent touch and pen input detection period (second period). As shown in FIG. 2, each period is periodically repeated, and the period from the reception preparation period to the touch and pen input detection period is one record.

Further, as shown in FIG. 2, the reception preparation signals output to the drive lines D ₀ to D _n have the same waveforms, and the synchronization signals output to the drive lines D ₀ to D _n are Each has the same waveform, and the data transmission signal output to each drive line D ₀ to D _n has the same waveform.

On the other hand, the drive signals output to the drive lines D ₀ to D _n have waveforms in which the potentials sequentially become High. That is, at the timing when the potential of the drive signal of the drive line D _n-1 changes from high to low, the potential of the drive signal of the next drive line D _n changes from low to high.

(Various signals)
The reception preparation signal is output to each of the drive lines D ₀ to D _n in a reception preparation period which is a period immediately before the synchronization period. The stylus pen 3 detects the reception preparation signal output to each drive line D ₀ to D _n , and adjusts (corrects) the phase and / or amplitude of the subsequent signal with reference to the detected reception preparation signal. The reception preparation period may be provided immediately before the data transmission period, and the reception preparation signal may be output to each of the drive lines D ₀ to D _n in the reception preparation period.

The synchronization signal is output to each of the drive lines D ₀ to D _n in the synchronization period following the reception preparation period. When the stylus pen 3 detects the synchronization signal output to each of the drive lines D ₀ to D _n , the drive timing of the stylus pen 3 and the drive timing of the touch panel controller 4 are synchronized.

The data transmission signal is output to each of the drive lines D ₀ to D _n in the data transmission period following the synchronization period. The data transmission signal includes drive information of the touch panel 2. The stylus pen 3 already synchronized with the touch panel controller 4 in the synchronization period detects the data transmission signal output to each of the drive lines D ₀ to D _n , whereby the drive information of the touch panel 2 is transmitted to the stylus pen 3. Ru.

The drive signal is output to each of the drive lines D ₀ to D _n in the touch and pen input detection period following the data transmission period. The touch panel controller 4 drives each of the drive lines D ₀ to D _n by the drive signal, and detects a change in capacitance of the touch panel 2 due to a touch operation via each of the sense lines S ₀ to S _m. It has become.

Further, by changing the capacitance of the touch panel 2 by driving the pen tip of the stylus pen 3 by a signal waveform indicated by D _{n + 1} in FIG. 2, through each of the sense lines S _{0 ~} S _m, the electrostatic A change in capacity is detected, and the touch panel controller 4 detects additional information such as the state of whether or not the button provided on the stylus pen 3 is pressed by the user and the writing pressure.

In the present embodiment, as shown in the figure, driving of drive lines D ₀ to D _n and driving of a pen point using a signal waveform corresponding to D _{n + 1} will be sequentially driven. However, even if the driving of drive lines D ₀ to D _{n and} the driving of the pen tip using a signal waveform corresponding to D _{n + 1} are parallelly driven using an M-sequence signal, a Hadamard code string, or the like as a code string. In the case where parallel driving is used, the position of the object to be detected may be detected from the correlation value obtained by performing a correlation operation of the code string, and the detection is performed from the restored value obtained by performing a recovery operation of the code string. The position of the object may be detected.

When parallel driving is performed for driving the drive lines D ₀ to D _n and driving a pen tip using a signal waveform corresponding to D _{n + 1} , the number of times of sensing (the number of integrations) can be increased. It is possible to realize a touch panel that improves the N ratio and performs position detection with high accuracy.

In the present embodiment, the data transmission period is a period immediately after the synchronization period, but the data transmission period may be provided immediately after the touch and pen input detection period. Further, in the present embodiment, the reception preparation period is a period immediately before the synchronization period, but the reception preparation period may be a period immediately before the data transmission period, and the reception preparation period is immediately before the synchronization period and the data. It may be provided immediately before the transmission period.

<Configuration of touch panel>
FIG. 3 is a view showing a schematic circuit configuration of the touch panel 2 provided in the touch panel system 1.

As shown, a plurality (n) of drive lines D ₀ to D _n extending in the left and right direction in the figure are provided in parallel and intersect with the drive lines D ₀ to D _n in the figure. sense line S _{0 ~} S _m extending in the vertical direction are provided in parallel a plurality (m pieces) of. Capacitances C ₀₀ to C _nm are provided at the intersections of the drive lines D ₀ to D _n and the sense lines S ₀ to S _m . The m and n may be the same or different.

The stylus pen 3 detects synchronization signals output from the touch panel controller 4 to the drive lines D ₀ to D _n by approaching the touch surface of the touch panel 2, and is synchronized with the touch panel controller 4.

Then, the touch panel controller 4 drives each of the drive lines D ₀ to D _n during the touch and pen input detection period shown in FIG. 2 and causes the above-mentioned touch by the touch via each of the sense lines S ₀ to S _m. A change in capacitance is detected, and the touch position and / or the distance between the touch panel 2 and the stylus pen 3 are calculated.

<Configuration of stylus pen and pen pressure sensor function>
The stylus pen 3 according to the present embodiment has, for example, a pen pressure sensor for detecting pen pressure, and a pen pressure signal from the pen pressure sensor is output while being synchronized with the touch panel controller 4. It is supposed to be. However, the stylus pen 3 is not necessarily limited thereto, and may not have a writing pressure sensor for detecting writing pressure.

FIG. 4 is a cross-sectional view showing the configuration of the stylus pen 3.

As shown in FIG. 4, the stylus pen 3 has a pen main body 5 which a user holds by hand having a conductive grip portion 5 a formed in a substantially cylindrical shape for the user to hold by hand. At the tip of the pen tip portion 6 is provided which is pressed against the touch panel 2 at the time of touch operation.

The pen tip portion 6 is provided on the pen tip shaft 6 b, insulators 6 c and 6 c for holding the pen tip cover 6 a axially movably movably in the axial direction, and the back side of the pen tip shaft 6 b And a writing pressure sensor 6d.

The pen point cover 6a is made of an insulating material, and the pen point shaft 6b is made of a conductive material, such as a metal or a conductive synthetic resin.

The pen pressure sensor 6 d is, for example, a semiconductor piezoresistive pressure sensor, and a semiconductor strain gauge is formed on the surface of a diaphragm (not shown). Therefore, when the pen tip cover 6a of the pen tip 6 is pressed against the touch panel 2 at the time of touch operation, the pen tip shaft 6b is pushed through the pen tip cover 6a to press the diaphragm surface of the writing pressure sensor 6d. As a result, the change in electrical resistance due to the piezoresistive effect caused by deformation of the diaphragm is converted into an electrical signal. Thereby, the pen pressure in the stylus pen 3 can be detected. Furthermore, the principle of pen pressure detection is not limited to this, and other detection principles can be adopted.

Inside the pen body 5, the connection switch 7, the control circuit 8, the operation changeover switches 9a and 9b, the sense circuit 10, the synchronization signal detection circuit 11, the timing adjustment circuit 12, and the drive circuit 13 Is provided. Furthermore, the connection switch 7 can be omitted. When the connection switch 7 is omitted, the output of the control circuit 8 is connected to the pen tip shaft 6b.

The connection switch 7 is an electronic switch composed of a field effect transistor (FET) or the like, and is controlled on / off by the control circuit 8. Here, when the connection switch 7 is off, the pen tip cover 6 a is electrically disconnected from the grip 5 a of the pen main body 5. At this time, since the component capacity of the pen tip portion 6 is extremely small, the touch panel system 1 does not recognize proximity / contact of the stylus pen 3 even if the pen tip cover 6 a is brought close to the touch panel 2.

On the other hand, when the connection switch 7 is turned on, the pen point cover 6a is electrically connected to the grip 5a of the pen body 5 via the pen tip shaft 6b, and the human body is connected to the pen point cover 6a via the grip 5a. It conducts. As a result, since the human body has a relatively large capacitance, when the stylus pen 3 approaches and contacts the touch panel 2, the charges accumulated in the above-described respective capacitances C ₀₀ to C _nn of the touch panel 2 change. The touch panel system 1 can detect the touch state of the stylus pen 3.

Further, the stylus pen 3 is provided with, for example, a push-type first operation switch 14a and a second operation switch 14b, and the first operation switch 14a and the second operation switch 14b are depressed to operate the first operation switch 14a and the second operation switch 14b. The functions assigned to the one operation switch 14 a and the second operation switch 14 b are executed via the control circuit 8. As a function assigned to the first operation switch 14a, for example, an eraser function can be mentioned, and it is possible to perform on / off of the eraser function by the first operation switch 14a. Further, as a function assigned to the second operation switch 14b, for example, a right click function of a mouse can be mentioned, and the right click function of this mouse can be turned on / off by the second operation switch 14b. is there.

Furthermore, the eraser function and the right click function of the mouse are one example, and not limited to the eraser function and the right click function of the mouse. Moreover, it is also possible to provide another operation switch and to add another function.

The touch position of the stylus pen 3 on the touch panel 2 is detected by touching the stylus pen 3 on the touch panel 2 with the connection switch 7 of the stylus pen 3 turned on.

In the present embodiment, in order to detect the driving of the pen tip portion 6 in the stylus pen 3 by the touch panel controller 4, the pen tip of the stylus pen 3 is driven with a waveform corresponding to the drive line D _{n + 1.} Change the capacitance on the touch surface of the sensor, and detect the change in the capacitance via each of the sense lines S ₀ to S _m , and the user presses a button provided on the stylus pen 3 The touch panel controller 4 is designed to detect additional information such as the state of the brush and the pen pressure.

<Configuration of Touch Panel Controller>
FIG. 5 is a view showing a schematic configuration of the touch panel controller 4 provided in the touch panel system 1.

As illustrated, the touch panel controller 4 includes a drive line drive circuit 15 (drive circuit), a sense amplifier 16, a timing generator 17, a control unit 18, an AD converter 19, and a processing unit 20. And a driving capability control unit 21.

The drive line drive circuit 15 drives the reception preparation signal generated based on the clock signal CL generated by the timing generator 17, the synchronization signal, the data transmission signal, and the drive signal for each of the drive lines D ₀ to D. It is a circuit which outputs to _n .

The sense amplifier 16 is a circuit that acquires capacitance data via each of the sense lines S ₀ to S _m based on the clock signal CL generated by the timing generator 17 and the drive signal, and sends it to the AD converter 19. It is.

The timing generator 17 is a circuit that generates a clock signal CL and a synchronization signal based on the clock signal CL, and sends the clock signal CL to the drive line drive circuit 15, the sense amplifier 16, the control unit 18, and the like.

The AD converter 19 is a circuit that converts the capacity data into digital data and sends the digital data to the processing unit 20.

The processing unit 20 determines, from the above-mentioned volume data, information on the touch position, the size of the touch response of the stylus pen 3 to the touch panel 2, that is, the information convertible by the user to the distance between the touch panel 2 and the stylus pen 3. It detects additional information such as the state of whether or not the button provided on the stylus pen 3 is pressed and the writing pressure. Then, the processing unit 20 executes a process corresponding to the detected information.

The control unit 18 outputs a selection signal for identifying the synchronization period, the data transmission period, and the touch and pen input detection period to the drivability control unit 21 during the reception preparation period. Furthermore, during the preparation for reception, during the synchronization, and during the data transmission, the control unit 18 performs thinning based on the touch response magnitude data (information on the distance between the touch panel 2 and the stylus pen 3). It is decided whether to output a signal to the drive line drive circuit 15 or not. That is, if the touch response magnitude data is equal to or greater than a predetermined value, a thinning signal is output, and if the touch response magnitude data is less than the predetermined value, the drive signal is output without thinning the drive line. Therefore, during the reception preparation period, during the synchronization period, and during the data transmission period, when the touch response magnitude data is equal to or greater than a predetermined value, that is, the distance between the touch panel 2 and the stylus pen 3 is closer than a predetermined value. In this case, the sync signal thinned out from the drive line drive circuit 15 is output.

The drive capacity control unit 21 is a circuit that sets the drive capacity (drive capacity) of the drive line drive circuit 15 independently for each period based on the selection signal supplied from the control unit 18. The drive capacity of the drive line drive circuit 15 is an index related to the amount of current that can be output by the drive line drive circuit 15, and the drive line drive circuit 15 outputs the drive line to the drive line by enhancing the drive capacity of the drive line drive circuit 15. Time constant of the signal waveform becomes short (delay time due to rising and falling becomes short).

The drive capability control unit 21 includes a selector 21a, a first drive control circuit 21b, a second drive control circuit 21c, a third drive control circuit 21d, and a fourth drive control circuit 21e.

The first drive control circuit 21 b outputs a drive capacity setting value for setting the drive capacity of the drive line drive circuit 15 during the reception preparation period to the selector 21 a. The second drive control circuit 21 c outputs a drive capacity setting value for setting the drive capacity of the drive line drive circuit 15 during the synchronization period to the selector 21 a. The third drive control circuit 21 d outputs a drive capacity setting value for setting the drive capacity of the drive line drive circuit 15 during the data transmission period to the selector 21 a. The fourth drive control circuit 21 e outputs a drive capacity setting value for setting the drive capacity of the drive line drive circuit 15 during the touch and pen input detection period to the selector 21 a.

Based on the selection signal, the selector 21a sets the drive capability setting value in the reception preparation period, the drive capability setting value in the synchronization period, the drive capability setting value in the data transmission period, and the touch and pen input. One of four signals of the drive capability setting value in the detection period is selected, and the selected drive capability setting value is output to the drive line drive circuit 15 as a drive capability setting signal.

<Basic operation of synchronization between touch panel controller and stylus pen>
The stylus pen 3 of the present embodiment wirelessly transmits and receives signals to and from the touch panel controller 4. Therefore, the pen tip portion 6 is driven in the same pattern as driving the virtual drive line D _{n + 1} so as to match the drive timing of the drive lines D ₀ to D _n in the touch panel controller 4. Therefore, in the stylus pen 3, the drive circuit 13 is provided to drive the same as the driver of the touch panel controller 4.

The drive of the drive lines D ₀ to D _n in the touch panel controller 4 is based on the drive timing generated by the timing generator 17 (FIG. 5). Therefore, the stylus pen 3 also has to operate in synchronization with the timing at which the touch panel controller 4 is driven. Therefore, in the stylus pen 3 of the present embodiment, by providing the sense circuit 10, the synchronization signal detection circuit 11, and the timing adjustment circuit 12, the stylus pen 3 detects the synchronization signal driven by the touch panel controller 4 and The timing of the synchronization signal of the touch panel controller 4 and the timing of the pen synchronization signal generated by the timing adjustment circuit 12 in the stylus pen 3 are made to coincide with each other.

The driving operation of the stylus pen 3 is a synchronization for detecting the synchronization signal from the touch panel controller 4 by the sense circuit 10 and the synchronization signal detection circuit 11 with the operation switch 9a turned on and the operation switch 9b turned off. It consists of a repetition of three periods of a signal detection period, a preparation period, and a drive mode period in which the operation switch 9a is turned off and the operation switch 9b is turned on to drive the pen tip 6 by the drive circuit 13. There is.

The synchronization signal detection period is a waiting period for detecting a bit pattern representing a synchronization waveform, and is a period during which the drive of the pen tip 6 is turned off and a synchronization signal pattern is detected from the pen tip signal waveform.

The above-mentioned preparation period is a preparation period for starting to drive the pen tip in synchronization with the touch panel controller 4 after detecting the synchronization signal pattern, and is a period for taking a drive start timing.

The drive mode period is a period in which the pen tip portion 6 is driven by the drive circuit 13 and is a period in which the pen tip portion 6 is driven while finely adjusting the edge of the drive waveform to match the drive timing of the touch panel controller 4. is there. At this time, the drive circuit 13 of the stylus pen 3 is driven in accordance with the drive timing of the touch panel controller 4.

FIG. 6 is a diagram showing the correspondence between the magnitude of the synchronization signal detected by the stylus pen 3 and the magnitude of the touch response of the stylus pen 3 to the touch panel 2 detected by the touch panel controller 4.

FIG. 6A is a diagram showing a case where the touch surface of the touch panel 2 and the stylus pen 3 are relatively far apart, and in such a case, the waveform of the synchronization signal is hardly detected by the stylus pen 3 . Then, the touch response of the stylus pen 3 to the touch panel 2 detected by the touch panel controller 4 is also determined to be non-touch response since the touch surface of the touch panel 2 and the stylus pen 3 are relatively far apart.

FIG. 6B is a diagram showing a case where the touch surface of the touch panel 2 and the stylus pen 3 are relatively close, and in such a case, the stylus pen 3 detects a small waveform of the synchronization signal. . Then, the magnitude of the touch response of the stylus pen 3 to the touch panel 2 detected by the touch panel controller 4 is determined to be small, since the touch surface of the touch panel 2 and the stylus pen 3 are relatively close.

FIG. 6C shows a case where the touch surface of the touch panel 2 and the stylus pen 3 are in contact with each other. In such a case, the stylus pen 3 detects a waveform of a large synchronization signal. Then, since the touch surface of the touch panel 2 and the stylus pen 3 are in contact with each other, the magnitude of the touch response of the stylus pen 3 detected by the touch panel controller 4 is determined to be large.

Note that the magnitude of the touch response of the stylus pen 3 to the touch panel 2 detected by the touch panel controller 4, that is, the distance between the touch panel 2 and the stylus pen 3 is within the touch and pen input detection period shown in FIG. The drive lines D ₀ to D _n are driven, and the change in capacitance due to touch is detected and calculated through the sense lines S ₀ to S _m .

<Drivability setting signal>
The drive capability setting signals corresponding to various periods will be described in detail below.

FIG. 7 is a diagram showing how to determine the drive capability setting value, where (a) is a diagram showing how to determine the drive capability setting value during the synchronization period, and (b) is a diagram showing the drive capability setting value during the data transmission period. It is a figure which shows how to decide.

In the reception preparation period, synchronization period, and data transmission period, each signal driven by the drive line is detected / received by the synchronization signal detection circuit 11 in the touch pen. Although the rise / fall of the signal on the sync signal detection circuit 11 occurs behind the rise / fall of the signal on the drive line, this delay time is short when the load of the sync signal detection circuit 11 is sufficiently small. In FIG. 7, the same waveform as that driven by the drive line is illustrated as being instantaneously appearing on the synchronization signal detection circuit 11.

(Synchronization signal)
As shown in FIG. 7A, it is assumed that the synchronization signal output to the drive line is switched between High and Low at the timing of the arrow in the drawing (drive start timing). In the synchronization period, the synchronization signal detection circuit 11 always attempts to detect the signal on the drive line at the frequency of the basic clock cycle, and detects the completion of the switching of High and Low of the signal (timing indicated by the black arrow in the figure). ) Are recognized as the rising and falling timings (synchronization detection timing) of the synchronization signal. Thus, the synchronization signal detection circuit 11 detects the synchronization signal.

Therefore, for the synchronization signal detection circuit 11 to accurately detect the synchronization signal, the rising and falling of the synchronization signal detected by the synchronization signal detection circuit 11 are completed during the symbol period of the synchronization signal on the drive line. It is sufficient to shorten the time constant of the synchronization signal sufficiently.

That is, the driving capability of drive line drive circuit 15 is sufficiently high to perform synchronization so that the rising and falling of the synchronization signal on synchronization signal detection circuit 11 are completed during the symbol period of the synchronization signal on the drive line. The time constant of the signal may be shortened. On the other hand, by increasing the drive capability of the drive line drive circuit 15, the electromagnetic interference at high frequency components becomes large.

Therefore, it is preferable that the drive capacity setting value in the synchronization period be the minimum of the drive capacity of the drive line drive circuit 15 in the synchronization period in the range where the synchronization signal detection circuit 11 can accurately detect the synchronization signal. . As a result, it is possible to synchronize the touch panel controller 4 and the stylus pen 3 and to realize the suppression of the malfunction due to the electromagnetic interference wave and the reduction of the power consumption.

(Receive preparation signal)
In the reception preparation period, in order to inform the touch pen of the phase and amplitude of the signal on the drive line in the subsequent period, the reception preparation signal must be output to the drive line under the same conditions as the signal of the subsequent period including the drive capability. You must.

Therefore, the driving ability setting value of the reception preparation period is required to be equal to the driving ability setting value of the subsequent period. In the present embodiment, since the reception preparation period is a period immediately before the synchronization period, the drive capability setting value of the reception preparation period is assumed to be equal to the drive capability setting value of the synchronization period.

(Data transmission signal)
As shown in FIG. 7B, it is assumed that the data transmission signal output to the drive line is switched between High and Low at the timing of the arrow in FIG. 7 (drive start timing). In the data transmission period, the synchronization signal detection circuit 11 performs data reception (detects a data transmission signal on the drive line) at a timing (black arrow in the figure) determined from the timing of synchronization detection in the synchronization period.

Therefore, in order for synchronization signal detection circuit 11 to receive data correctly, the timing from the timing of the rise start or the fall start of the data transmission signal on the drive line to the timing of the data reception (black arrow in the figure). The time constant of the data transmission signal may be made sufficiently short so that the rising and falling of the data transmission signal are completed.

That is, the driving power of the drive line is sufficiently high to shorten the time constant of the data transmission signal so that the rise and fall of the data transmission signal are completed between the drive start timing of the drive line and the data reception timing. do it. On the other hand, by increasing the drive capability of the drive line drive circuit 15, the electromagnetic interference at high frequency components becomes large.

Therefore, the drivability setting value in the data transmission period minimizes the drivability of the drive line drive circuit 15 in the data transmission period in a range where the synchronization signal detection circuit 11 can accurately detect the data transmission signal. Is preferred. As a result, the drive information of the touch panel controller 4 can be transmitted to the stylus pen 3, and the suppression of erroneous operation due to the electromagnetic interference wave and the reduction of the power consumption can be realized.

As described above, also in the data transmission period, the drive capability is determined as in the synchronization period. Since the signal period in the data transmission period is longer than the signal period in the synchronization period, the optimum value of the drivability in the data transmission period can be equal to or less than the optimum value of the drivability in the synchronization period. That is, the magnitude of the influence of the electromagnetic interference wave in the data transmission period can be suppressed to be equal to or less than the magnitude of the influence of the electromagnetic interference wave in the synchronization period.

(Drive signal)
FIG. 8 is a diagram showing how to determine the drive capability setting value during the touch and pen input detection period.

As shown in FIG. 8, the touch panel controller 4 drives a signal on the drive line at the same time as the reset period of the sense circuit (a period when the reset signal is high) ends (a rise of the drive signal on the drive line Or falling starts).

Then, at a certain point (detection timing) before the reset period of the next sense circuit starts, the touch panel controller 4 detects a signal on the sense line. The detection timing may be a predetermined timing.

The signal waveform on the sense line changes in response to the rise or fall of the drive signal on the drive line. A predetermined time (settling time) is required until the signal waveform on the sense line becomes stable from the timing when the rising or falling of the drive signal on the drive line starts (drive start timing).

In order for the touch panel controller 4 to accurately detect the signal on the sense line, the touch panel controller 4 needs to detect the signal on the sense line while the signal waveform on the sense line is stable.

Therefore, if the drive signal of drive line drive circuit 15 is sufficiently high and the time constant of the drive signal is shortened, the settling time will be shorter than the time from drive line drive start timing to sense line detection timing. Good. On the other hand, by increasing the drive capability of the drive line drive circuit 15, the electromagnetic interference at high frequency components becomes large.

Therefore, the drivability setting value during the touch and pen input detection period minimizes the drivability of the drive line drive circuit 15 during the touch and pen input detection period as long as the signal on the sense line can be accurately detected. Is preferred. As a result, accurate detection of the touch position can be performed by the touch panel controller 4, and suppression of malfunction due to the electromagnetic interference wave and reduction in power consumption can be realized.

As described above, the time constants permitted for the reception preparation signal, synchronization signal, data transmission signal, and drive signal are different from one another. Therefore, in each of the reception preparation period, the synchronization period, the data transmission period, and the touch and pen input detection periods, the optimum drive capabilities of the drive line drive circuit 15 may differ from one another.

The touch panel controller 4 includes the drive capacity control unit 21. Therefore, the drive capacity of the drive line drive circuit 15 can be set individually for each period. Therefore, the drive capability of the drive line drive circuit 15 can be optimized in each period.

In the present embodiment, the first drive control circuit 21b, the second drive control circuit 21c, the third drive control circuit 21d, and the fourth drive control circuit 21e are each determined in advance experimentally or a priori. The drive capacity setting value may be stored.

In the present embodiment, although the reception preparation signal, the synchronization signal, and the data transmission signal are described as being emitted from the touch panel controller 4 to the stylus pen 3, they may be emitted to an external device other than the stylus pen 3. Good.

(Modification)
In the first embodiment, the control unit 18 outputs the thinning signal to the drive line drive circuit 15. However, the present invention is not limited to this.

For example, the first drive control circuit 21b, the second drive control circuit 21c, the third drive control circuit 21d, and the fourth drive control circuit 21e generate a thinning signal and output it to the selector 21a, and the selector 21a sets the drive capability. The signal and the decimation signal may be output together to the drive line drive circuit 15.

In the first embodiment, the control unit 18 is described as determining whether to output the thinning signal based on the magnitude of the touch response, but the present invention is not limited to this.

For example, the control unit 18 may determine whether to output a thinning signal based on the magnitude of the touch response and the coordinate data. In this case, the coordinate data is output from the processing unit 20 and sent to the control unit 18.

In the first embodiment, the drive capability control unit 21 controls the drive capability (time constant of the rise of the signal) of the drive line drive circuit 15, but the present invention is not limited to this.

For example, the control unit 18 outputs a voltage adjustment signal for adjusting the voltage of the synchronization signal and the data transmission signal to the drive line drive circuit 15, and the drive line drive circuit 15 generates the synchronization signal and data based on the voltage adjustment signal. The voltage of the transmission signal may be adjusted.

Also, for example, the control unit 18 outputs a drive pattern selection signal for adjusting the length of the synchronization signal to the drive line drive circuit 15, and the drive line drive circuit 15 outputs the length of the synchronization signal based on the drive pattern selection signal. You may adjust the

Here, it is preferable that the lengths of the reception preparation period, the synchronization period, the data transmission period, and the touch and pen input detection period be variable in accordance with the use condition of the touch panel 2. For example, when the amount of data transmission is large, the data transmission period may be extended to shorten the synchronization period. Then, along with changing the length of each period, it is preferable to change the drive capability of the drive line drive circuit 15 to optimize the rising and falling period of the waveform of each signal.

Therefore, in the touch panel controller 104 according to the first embodiment, the control unit 18 performs the first drive control circuit on information on the lengths of reception preparation period, synchronization period, data transmission period, and touch and pen input detection period. 21b, the second drive control circuit 21c, the third drive control circuit 21d, and the fourth drive control circuit 21e.

The first drive control circuit 21b, the second drive control circuit 21c, the third drive control circuit 21d, and the fourth drive control circuit 21e determine the drive capacity setting value of each period based on the information of the length of each period. The drive capability setting value may be output to the selector 21a.

Second Embodiment
Another embodiment of the present invention is described below with reference to FIGS. 9 to 10. In addition, about the member which has the same function as the member demonstrated in the said embodiment for convenience of explanation, the same code | symbol is appended and the description is abbreviate | omitted.

FIG. 9 is a view showing a schematic configuration of the touch panel controller 204 provided in the touch panel system 1 of the present embodiment. As shown in FIG. 9, the touch panel controller 204 includes a multiplexer 23.

Drive lines D ₀ to D _n are connected to the drive line drive circuit 15. Further, sense lines S ₀ to S _m are connected to the sense amplifier 16. Driveline drive circuit 15 via the multiplexer 23, to drive the horizontal signal lines _D L0 _{~ D Ln} or vertical signal lines _S L0 _{~ S Lm} of the touch panel 2, output a signal to the drive line _D 0 ~ _{D n} Do. The sense amplifier 16 acquires capacitance data from the sense lines S ₀ to S _m through the multiplexer 23.

The multiplexer 23 is a connection switching circuit that switches connections between a plurality of inputs and a plurality of outputs. The configuration of the multiplexer 23 will be described below with reference to FIG. FIG. 10 is a circuit diagram showing a configuration of multiplexer 23. Referring to FIG.

The multiplexer 23 (i) connects the horizontal signal lines D _L0 to D _Ln to the drive lines D ₀ to D _n and connects the vertical signal lines S _L0 to S _Lm to the sense lines S ₀ to S _m. And (ii) a second connection state in which the horizontal signal lines D _L0 to D _Ln are connected to the sense lines S ₀ to S _m and the vertical signal lines S _L0 to S _Lm are connected to the drive lines D ₀ to D _n Switch at a fixed cycle. For example, the odd record may be in the first connection state, and the even record may be in the second connection state.

Further, the multiplexer 23 is connected to the timing generator 17. The operation of switching between the first connection state and the second connection state in the multiplexer 23 is controlled by a control signal supplied from the timing generator 17.

Hereinafter, the state in which the touch panel 2 is driven in the first connection state is referred to as a first drive state, and the state in which the touch panel 2 is driven in the second connection state is referred to as a second drive state.

In the touch panel controller 204, the control unit 18 generates drive information indicating whether the touch panel 2 is driven by the first drive state or the second drive state as a data transmission signal, and outputs the data to the drive line drive circuit 15.

The drive line drive circuit 15 outputs a data transmission signal to drive lines D ₀ to D _n .

According to the above configuration, in the touch panel system in which the drive method of the touch panel 2 is periodically changed, the drive state of the touch panel 2 can be transmitted to the stylus pen 3 as drive information. Then, as in the first embodiment, when the data transmission signal is output to the drive line to transmit the drive state of the touch panel 2 to the stylus pen 3, the drive capability of the drive line drive circuit 15 is optimized. Generation of electromagnetic waves can be suppressed.

In the above description, the case where the information sent as the data transmission signal from the touch panel controller 4 and 204 is the drive information has been described, but the touch panel controller uses the data transmission information as arbitrary information used to drive the touch pen. You may send it. As an example, in order to initialize the stylus pen 3 or other external device from the touch panel controller by register writing, the case where the address of the register and the write value of the register are sent from the touch panel controller to the stylus pen or other external device may is there.

Third Embodiment
It will be as follows if other embodiment of this invention is described based on FIG. In addition, about the member which has the same function as the member demonstrated in the said embodiment for convenience of explanation, the same code | symbol is appended and the description is abbreviate | omitted.

FIG. 11 is a functional block diagram showing a configuration of a mobile phone 60 (electronic device) as an example of the electronic device including the touch panel system 1 of the first embodiment. In the present embodiment, the configuration in which the touch panel system 1 of the first embodiment is provided to the mobile phone 60 is exemplified, but the touch panel system of the second embodiment or the third embodiment may be provided to the mobile phone 60. .

The mobile phone 60 includes the touch panel system 1, the display panel 61, the operation key 62, the speaker 63, the microphone 64, the camera 65, a central processing unit (CPU) 66, a read only memory (ROM) 67, a random access memory (RAM) 68, And a display control circuit 69. The components of the mobile phone 60 are connected to each other by a data bus.

As described above, the touch panel system 1 includes the touch panel 2, the stylus pen 3, and the touch panel controller 4.

The display panel 61 displays an image stored in the ROM 67 or the RAM 68. The operation of the display panel 61 is controlled by the display control circuit 69.

The display panel 61 may be superimposed on the touch panel 2 or may incorporate the touch panel 2. The touch recognition signal indicating the touch position on the touch panel 2 generated by the touch recognition unit may have the same role as a signal indicating that the operation key 62 has been operated.

Operation key 62 accepts an input operation by the user of mobile phone 60. The speaker 63 outputs sound based on music data or the like stored in the ROM 67 or the RAM 68, for example.

The microphone 64 receives an input of voice from the user. The mobile phone 60 digitizes the input voice (analog data). Then, the mobile phone 60 transmits the digitized voice to the communication partner (for example, another mobile phone).

The camera 65 captures an image of a subject in response to an input operation to the operation key 62 by the user, and generates image data. The image data is stored in the ROM 67, the RAM 68, or an external memory (for example, a memory card).

The CPU 66 centrally controls the operation of the touch panel system 1 and the mobile phone 60. The CPU 66 also executes various programs stored in the ROM 67, for example.

The ROM 67 stores data in a non-volatile manner. The ROM 67 is a writable and erasable ROM such as an EPROM (Erasable Programmable ROM) or a flash memory. Although not shown in FIG. 8, the mobile phone 60 may be configured to include an interface for connecting to another electronic device by wire.

The RAM 68 volatileally stores data generated by execution of a program by the CPU 66 or data input through the operation key 62.

The mobile telephone 60 provided with the touch panel system 1 also achieves the same effect as the touch panel system 1 of the first embodiment.

In the present embodiment, the mobile phone 60 as an example of the electronic device provided with the touch panel system 1 is a camera-equipped mobile phone or a smartphone, but the electronic device provided with the touch panel system 1 is not limited thereto. For example, portable terminal devices such as tablets, and information processing devices such as PC monitors, signage, electronic blackboards, and information displays are also included in the electronic apparatus provided with the touch panel system 1.

[Summary]
The touch panel controller (4) according to aspect 1 of the present invention has a touch panel (a plurality of first signal lines (drive lines D ₀ to D _n ) and a plurality of second signal lines (sense lines S ₀ to S _m ) 2) a touch panel controller for driving a drive circuit for outputting a signal to the first signal line, and (drive line drive circuit 15) a drive capacity control section (21) for controlling the drive capacity of the drive circuit. The drive circuit is provided for synchronizing the drive timing of the touch pen (stylus pen 3) capable of giving an input operation to the touch panel in the first period (synchronization period) with the operation of the drive circuit. The synchronization signal is output to the first signal line, and the second period (touch and pen input detection period) different from the first period is performed. A detection signal (drive signal) for detecting an input operation to the touch panel is output to the first signal line, and the drive capacity control unit controls the drive capacity of the drive circuit in the first period, and And setting the drive capability of the drive circuit in the period of

According to the above configuration, the drive capability of the drive circuit in the first period and the drive capability of the drive circuit in the second period can be set. Thereby, even when the optimum value of the drive capability of the drive circuit in the first period and the optimum value of the drive capability of the drive circuit in the second period are different from each other, the drive capability of the drive circuit in each period is It can be optimized.

Thereby, the touch pen and the drive circuit can be normally synchronized in the first period, and the input operation to the touch panel can be accurately detected in the second period, and malfunction and power consumption due to electromagnetic interference are reduced. Can be realized.

In the touch panel controller according to aspect 2 of the present invention, in the aspect 1, the drive circuit drives the touch pen in a third period (data transmission period) different from the first period and the second period. A data transmission signal for giving the touch pen any information used to perform the operation to the first signal line, and the drive capability control unit controls the drive capability of the drive circuit in the third period. The configuration may be set.

According to the above configuration, the drive capability of the drive circuit in the first period, the drive capability of the drive circuit in the second period, and the drive capability of the drive circuit in the third period can be set. . Thus, the optimum value of the drive capability of the drive circuit in the first period, the optimum value of the drive capability of the drive circuit in the second period, and the optimum value of the drive capability of the drive circuit in the third period are different from each other. Even in this case, the drive capability of the drive circuit in each period can be optimized.

As a result, the drive state of the touch panel can be accurately given to the touch pen, and malfunction and reduction in power consumption due to electromagnetic interference can be realized.

In the touch panel controller according to aspect 3 of the present invention, in the aspect 1 or 2, the drive circuit is a period immediately before the first period, unlike the first period and the second period. In the fourth period (reception preparation period), a reception preparation signal having a waveform serving as a reference when correcting the synchronization signal received by the touch pen is output to the first signal line, and the drive capability control unit The drive capability of the drive circuit may be set in the fourth period.

According to the above configuration, the drive ability of the drive circuit in the first period, the drive ability of the drive circuit in the second period, the drive ability of the drive circuit in the third period, and the drive circuit in the fourth period And the driving ability of each can be set. Thereby, the optimum value of the drive capability of the drive circuit in the first period, the optimum value of the drive capability of the drive circuit in the second period, the optimum value of the drive capability of the drive circuit in the third period, and Even when the optimal value of the drive capability of the drive circuit in the period is different from each other, the drive capability of the drive circuit in each period can be optimized.

Thus, the synchronization signal can be accurately detected by correcting the synchronization signal received by the touch pen with reference to the reception preparation signal, and the malfunction due to the electromagnetic interference wave and the reduction of the power consumption can be realized. Can.

In the touch panel controller according to aspect 4 of the present invention, in the aspect 3 above, the drive capability control unit is configured to transmit the first period, the second period, the third period, and the fourth period. The drive capability of the drive circuit in each period may be set according to the length of the period.

According to the above configuration, even when the length of each period is changed, the drive capability of the drive circuit can be changed and optimized according to the change of the length of each period.

A touch panel system according to aspect 5 of the present invention includes the touch panel controller according to any one of aspects 1 to 4, a touch panel, and a touch pen.

An electronic apparatus (mobile phone 60) according to aspect 6 of the present invention includes the touch panel system according to aspect 5.

The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the claims, and embodiments obtained by appropriately combining the technical means disclosed in the different embodiments. Is also included in the technical scope of the present invention. Furthermore, new technical features can be formed by combining the technical means disclosed in each embodiment.

The present invention can be suitably used for a touch panel system provided with a touch panel, a touch panel controller, and a touch pen.

1 Touch panel system 2 Touch panel 3 Stylus pen (touch pen)
4, 104, 204 Touch panel controller 15 Drive line drive circuit (drive circuit)
21 drive capacity control unit 60 mobile phone (electronic device)
D0 to Dn drive line (first signal line)
S0 to Sm Sense line (second signal line)

Claims (5)

A touch panel controller for driving a touch panel having a plurality of first signal lines and a plurality of second signal lines intersecting the plurality of first signal lines.
A drive circuit for outputting a signal to the first signal line;
And a drive capability control unit for controlling the drive capability of the drive circuit,
The drive circuit outputs, to the first signal line, a synchronization signal for synchronizing, with the operation of the drive circuit, drive timing of the touch pen capable of giving an input operation to the touch panel in a first period. During a second period different from the first period, a detection signal for detecting an input operation to the touch panel is output to the first signal line,
The touch panel controller, wherein the drive capacity control unit sets the drive capacity of the drive circuit in the first period and the drive capacity of the drive circuit in the second period. The drive circuit transmits a data transmission signal for providing the touch pen with any information used to drive the touch pen in a third period different from the first period and the second period. Output to the first signal line
The touch panel controller according to claim 1, wherein the drive capacity control unit sets the drive capacity of the drive circuit in the third period. Unlike the first period and the second period, the drive circuit corrects the synchronization signal received by the touch pen in a fourth period which is a period immediately before the first period. Outputting a reception preparation signal having a waveform as a reference to the first signal line;
The touch panel controller according to claim 1, wherein the drive capacity control unit sets the drive capacity of the drive circuit in the fourth period. A touch panel system comprising the touch panel controller according to any one of claims 1 to 3, a touch panel, and a touch pen. An electronic device comprising the touch panel system according to claim 4.

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