JP5774902B2 - Touch sensor panel controller and touch detection device - Google Patents

Description

  The present invention relates to a touch sensor panel controller and a semiconductor device using the same, and relates to a technique effectively applied to, for example, a liquid crystal display panel unit in which a touch sensor panel unit is incorporated.

  A touch sensor panel that supports multi-point touch using the mutual capacitance method is arranged such that, for example, a Y electrode as a drive electrode and an X electrode as a detection electrode are perpendicular to each other with a dielectric interposed therebetween, and a cross coupling is provided at each intersection. An intersection capacitance as a capacitance is formed. When there is a finger or hand capacitance in the vicinity of the intersection capacitance, the mutual capacitance of the node decreases by the combined capacitance of the finger or hand. The touch sensor panel controller detects the intersection capacitance at which this change in mutual capacitance has occurred, and the Y electrode is pulse-driven in the order of electrodes to perform a charging operation in units of pulses, and the intersection of the Y electrode and the X electrode. The operation of measuring the capacitance value of the portion through the X electrode is sequentially repeated, so that the distribution data of the capacitance value of the intersection portion of the Y electrode and the X electrode can be acquired. For example, Patent Document 1 discloses a controller that controls driving of a touch sensor panel using such a mutual capacitance method. In Patent Document 1, when the Y electrode is driven in an AC pulse order in the order of electrodes, a charge signal appearing on the X electrode via an intersection capacitance associated with the Y electrode is integrated by an integration circuit to obtain a measurement signal.

US Patent Publication No. 2007 / 0257890A1

  The inventor studied noise when driving the Y electrode with a drive pulse in the touch sensor panel controller. When the finger touches the touch sensor panel, the capacitance value at the intersection of the Y electrode and the X electrode only changes by about 1 pF at most, and in order to extract the change by a large signal, the voltage of the drive pulse was increased. That is, when the Y electrode is pulse-driven with a high voltage, the amount of charge accumulated in the capacitance at the intersection by one pulse drive increases, so that the signal component can be enlarged and a high S / N ratio can be obtained.

  However, considering that the touch sensor panel is placed over the liquid crystal display panel, if the pulse voltage for driving the Y electrode is high, the liquid crystal display panel will cause noise due to capacitive coupling at the rise and fall of the pulse. It has been made clear by the present inventor that display quality may be greatly affected and display quality may be deteriorated. Furthermore, it has been found by the present inventor that there is a need to be able to cope with the difference in the influence of noise depending on the characteristics of the liquid crystal display panel and the mounting form of the touch sensor panel.

  Patent Document 1 describes the relationship between the touch sensor panel and the liquid crystal display panel, but noise that becomes a problem when the pulse drive voltage of the Y electrode is increased has not been sufficiently studied.

  An object of the present invention is to provide a touch sensor panel controller that can alleviate the influence of noise caused by rising and falling of a pulse drive voltage with respect to a Y electrode.

  Another object of the present invention is to provide a touch detection device that can alleviate the influence of noise caused by rising and falling of a pulse drive voltage with respect to a Y electrode.

  The above and other objects and novel features of the present invention will be apparent from the description of this specification and the accompanying drawings.

  The following is a brief description of an outline of typical inventions disclosed in the present application.

  That is, the drive circuit for driving the Y electrode of the touch sensor panel in which a plurality of intersection capacitances are formed by the plurality of Y electrodes and the X electrode outputs a drive pulse signal whose waveform during rising and falling is variable. Output to electrode.

  The effects obtained by the representative ones of the inventions disclosed in the present application will be briefly described as follows.

  That is, it is possible to mitigate the influence of noise caused by the rise and fall of the pulse drive voltage with respect to the Y electrode.

FIG. 1 is an explanatory diagram showing the overall configuration of a display and input device to which the present invention is applied. FIG. 2 is an explanatory diagram illustrating the electrode configuration of the touch sensor panel. FIG. 3 is an explanatory diagram illustrating the electrode configuration of the display panel. FIG. 4 is a block diagram illustrating the overall configuration of the touch sensor panel controller. FIG. 5 is a circuit diagram showing an example of an integration circuit as an equivalent circuit and a detection circuit of the touch sensor panel. FIG. 6 is a timing chart showing an example of pulsed AC driving for the Y electrode. FIG. 7 is a timing chart illustrating the input pulse voltage to the Y electrode and the timing of the detection operation by the integration circuit. FIG. 8 is a circuit diagram illustrating an equivalent circuit of a liquid crystal display panel and a driving circuit of a liquid crystal driver. FIG. 9 is a timing chart illustrating the drive timing of the gate electrode. FIG. 10 is a timing chart illustrating the timing waveforms of the gate pulse applied to the gate electrode and the gradation voltage applied to the drain electrode. FIG. 11 is an explanatory diagram showing an example in which the waveform slope and the intermediate voltage of the slope are made variable as an aspect of making the waveform during the rise and fall of the drive waveform variable. FIG. 12 is an explanatory diagram showing an example in which the switching timing of the waveform slope is made variable as an aspect of making the waveform during the rise and fall of the drive waveform variable. FIG. 13 is a circuit diagram illustrating the configuration of an output waveform variable selection unit in the drive circuit. FIG. 14 is a waveform diagram showing an example of a pulse waveform generated via the variable selection unit of FIG. FIG. 15 is an explanatory view schematically showing the influence of the drive waveform of FIG. 14 on the liquid crystal display panel. FIG. 16 is a circuit diagram illustrating another configuration of the output waveform variable selection unit in the drive circuit and the configuration of the power supply circuit used therefor. FIG. 17 is a waveform diagram showing an example of a pulse waveform generated through the variable selection unit and the power supply circuit of FIG. FIG. 18 is an explanatory diagram schematically showing the influence of the drive waveform of FIG. 17 on the liquid crystal display panel. FIG. 19 is a circuit diagram showing, as a comparative example, a drive circuit in which the drive pulse waveform for the Y electrode is simply a rectangular wave. FIG. 20 is a waveform diagram showing an example of the pulse waveform generated in FIG. FIG. 21 is an explanatory view schematically showing the influence of the drive waveform of FIG. 20 on the liquid crystal display panel.

1. First, an outline of a typical embodiment of the invention disclosed in the present application will be described. Reference numerals in the drawings referred to in parentheses in the outline description of the representative embodiments merely exemplify what are included in the concept of the components to which the reference numerals are attached.

[1] <Driving pulse signal in which the waveform during rising and falling is variably set>
The touch sensor panel controller (3) according to the representative embodiment of the present invention includes a touch in which a plurality of intersection capacitances (Cxy) are formed by a plurality of Y electrodes (Y1 to YM) and X electrodes (X1 to XN). A drive circuit (300, 300A) for driving the Y electrode of the sensor panel, a detection circuit (301) for measuring the capacitance value of the intersection via the X electrode, and a control circuit for controlling the drive circuit and the detection circuit (308). The drive circuit outputs, to the Y electrode, a drive pulse signal in which the waveform during rising and falling is variably set based on control by the control circuit.

  According to this, since the waveform during the rise and fall of the drive pulse signal can be set variably according to the characteristics of the liquid crystal display or the like affected by noise, the rise and rise of the pulse drive voltage with respect to the Y electrode can be set. It is possible to reduce the influence of noise caused by the decrease.

[2] <Switch circuit for selecting drive voltage>
In the touch sensor panel controller according to item 1, the drive circuit includes a switch circuit (310, 310A) that selects a required drive voltage from among a plurality of drive voltages, and the control circuit follows a designated waveform mode. A switch control signal for the switch circuit is generated.

  According to this, it is possible to easily realize variable setting with respect to the waveform during the rise and fall of the drive pulse signal.

[3] <Switch circuit for selecting drive voltage and output resistance value>
2. The touch sensor panel controller according to item 1, wherein the drive circuit selects a required drive voltage from a plurality of drive voltages (VL, GND, VH) and selects an output resistance value (R) of the drive voltage. (310), and the control circuit generates a switch control signal of the switch circuit according to the instructed waveform mode.

  According to this, it is possible to finely set the waveform change point and the waveform inclination with respect to the waveform during the rise and fall of the drive pulse signal.

[4] <Selection of ground, positive and negative voltage>
In the touch sensor panel controller according to item 3, the switch circuit (310) arbitrarily selects a ground voltage (GND), a positive voltage (VH) with respect to the ground voltage, or a negative voltage (VL) with respect to the ground voltage. A plurality of first switches (SW1 to SW3) that output to the Y electrode and a plurality of second switches (SW4, SW4) that arbitrarily select the positive voltage or negative voltage and output to the Y electrode via the resistance element (R) SW5).

  According to this, it becomes easy to finely set the waveform change point and the waveform inclination with respect to the waveform during the rise and fall of the drive pulse signal.

[5] <Overdrive>
In the touch sensor panel controller according to item 2, the switch circuit (310A) includes a first voltage (VLL), a second voltage (VL), a third voltage, and a fourth voltage (VH) that sequentially go from a low level to a high level. A plurality of switches (SW1 to SW4) for selecting (VHH), and the control circuit sequentially selects the second voltage selection, the fourth voltage selection, the third voltage selection, and the first voltage in units of a pulse period of the drive pulse. Control the selection.

  According to this, at the rising edge of the pulse waveform, an overdrive waveform that exceeds the third voltage and reaches the fourth voltage is formed to return to the third voltage, and at the falling edge of the pulse waveform, the first voltage that is lower than the second voltage is reached. A pulse waveform that forms an overdrive waveform and returns to the second voltage can be generated. In particular, when the drive waveform propagates from one side of the Y electrode, the dullness of the change in the propagation signal gradually increases due to the delay component of the electrode, but the degree of the dullness is mitigated by the overdrive waveform, regardless of the position along the Y electrode. Therefore, the influence of noise can be made uniform. Uniformization of the influence of noise can contribute to alleviation of an undesirable influence due to noise.

[6] <Control register>
In the touch sensor panel controller according to item 2, the control circuit includes a control register (320) in which a waveform mode is set so as to be rewritable.

  Accordingly, the waveform mode can be easily set.

[7] <Controlling microprocessor>
The touch sensor panel controller according to item 6 further includes a microprocessor (5) for performing data processing using the setting of the waveform mode for the control register and the detection result of the detection circuit.

  According to this, the waveform mode can be easily set via the data processor software.

[8] <Driving pulse signal in which the waveform during rising and falling is variably set>
A touch detection device according to another embodiment of the present invention drives a touch sensor panel (1) in which a plurality of intersection capacitances are formed by a plurality of Y electrodes and X electrodes, and the Y electrodes of the touch sensor panel. The touch sensor panel controller (3) that measures the capacitance value at each intersection of the Y electrode and the X electrode via the X electrode, and the capacitance value at each intersection of the Y electrode and the X electrode transferred from the touch sensor panel controller And a microprocessor (5) for performing data processing based on the distribution data. The touch sensor panel controller drives the Y electrode by outputting a drive pulse signal in which the waveform during rising and falling is variably set based on the waveform mode instructed from the data processor.

  According to this, since the waveform during the rise and fall of the drive pulse signal can be set variably according to the characteristics of the liquid crystal display or the like affected by noise, the rise and rise of the pulse drive voltage with respect to the Y electrode can be set. It is possible to reduce the influence of noise caused by the decrease.

[9] <Switch circuit for selecting drive voltage>
In the touch detection device according to item 8, the touch sensor panel controller includes a switch circuit (310, 310A) that selects a required drive voltage from a plurality of drive voltages, and follows a waveform mode instructed by the microprocessor. A switch control signal for the switch circuit is generated.

  According to this, it is possible to easily realize variable setting with respect to the waveform during the rise and fall of the drive pulse signal.

[10] <Switch circuit for selecting drive voltage and output resistance value>
In the touch detection device according to item 8, the drive circuit includes a switch circuit (310) that selects a required drive voltage from a plurality of drive voltages and selects an output resistance value of the drive voltage, and the control circuit includes: The switch control signal of the switch circuit is generated according to the designated waveform mode.

  According to this, it is possible to finely set the waveform change point and the waveform inclination with respect to the waveform during the rise and fall of the drive pulse signal.

[11] <Selection of ground, positive and negative voltage>
The touch detection device according to Item 10, wherein the switch circuit (310) includes a plurality of first switches that arbitrarily select a ground voltage, a positive voltage with respect to the ground voltage, or a negative voltage with respect to the ground voltage and output the selected voltage to the Y electrode. (SW1 to SW3) and a plurality of second switches (SW4, SW5) that arbitrarily select the positive voltage or the negative voltage and output the selected voltage to the Y electrode via a resistance element.

  According to this, it becomes easy to finely set the waveform change point and the waveform inclination with respect to the waveform during the rise and fall of the drive pulse signal.

[12] <Overdrive>
In the touch detection device according to Item 9, the switch circuit (310A) includes a plurality of switches (SW11 to SW14) that select a first voltage, a second voltage, a third voltage, and a fourth voltage that are sequentially shifted from a low level to a high level. ). The touch sensor panel controller sequentially controls the second voltage selection, the fourth voltage selection, the third voltage selection, and the first voltage selection in units of the pulse period of the drive pulse.

  According to this, at the rising edge of the pulse waveform, an overdrive waveform that exceeds the third voltage and reaches the fourth voltage is formed to return to the third voltage, and at the falling edge of the pulse waveform, the first voltage that is lower than the second voltage is reached. A pulse waveform that forms an overdrive waveform and returns to the second voltage can be generated. In particular, when the drive waveform propagates from one side of the Y electrode, the dullness of the change in the propagation signal gradually increases due to the delay component of the electrode, but the degree of the dullness is mitigated by the overdrive waveform, regardless of the position along the Y electrode. Therefore, the influence of noise can be made uniform. Uniformization of the influence of noise can contribute to alleviation of an undesirable influence due to noise.

[13] <Control register>
In the touch detection device according to item 8, the touch sensor panel controller includes a control register (320) in which a waveform mode is set so as to be rewritable, and the microprocessor sets a waveform mode for the control register.

  According to this, it is possible to easily set the waveform mode.

2. Details of Embodiments Embodiments will be further described in detail.

  FIG. 1 is an explanatory diagram showing the overall configuration of a display and input device to which the present invention is applied. The display and input device shown in FIG. 1 constitutes a part of a portable terminal such as a PDA or a mobile phone, and includes a touch sensor panel (TP) 1, a liquid crystal display panel (DSP) 2 as a display panel, and a touch sensor panel controller. (TPC) 3 and a liquid crystal driver (DSPD) 4 as a display driver.

  The touch sensor panel controller 3 drives the touch sensor panel 1 based on the control of the subsystem microprocessor (SMPU) 5 as a control microprocessor and sequentially acquires and accumulates signals from the array of intersection capacitances. Then, the accumulated signal is returned to the microprocessor 5 for the subsystem. Here, the subsystem microprocessor means a microprocessor for configuring the subsystem with respect to the host processor 6.

  The touch sensor panel 1 is configured using a transmissive (translucent) electrode or a dielectric film, and is disposed, for example, on the display surface of the liquid crystal display 2 in a bitmap display form. The host processor (HMPU) 6 generates display data, and the liquid crystal display driver 4 performs display control for displaying the display data received from the host processor 6 on the liquid crystal display 2.

  The microprocessor 5 for the subsystem performs a digital filter operation on the signal received from the touch sensor panel controller 3, and when a touch event occurs on the touch sensor panel 3 based on the signal from which noise has been removed. The coordinates are calculated and given to the host processor 6. For example, the host processor 6 analyzes the input from the touch sensor panel 1 from the relationship between the display screen given to the liquid crystal display driver 4 and the coordinate data given from the subsystem microprocessor 5.

  FIG. 2 illustrates an electrode configuration of the touch sensor panel. The touch sensor panel 1 is configured such that a large number of Y electrodes Y1 to YM formed in the horizontal direction and a large number of X electrodes X1 to XN formed in the vertical direction are electrically insulated from each other. Each electrode is formed in a rectangular shape in the middle of its extending direction to constitute a capacitive electrode. A capacitance at the intersection is formed in the gap between the capacitive electrode connected to the X electrode and the capacitive electrode connected to the Y electrode. That is, a capacitance (intersection capacitance) is formed at the intersection of the X electrodes X1 to XN and the Y electrodes Y1 to YM. The Y electrodes Y1 to YM are driven by applying a pulse voltage in the order of electrode arrangement.

  FIG. 3 illustrates an electrode configuration of the display panel 2. The display size of the display panel 2 shown in the figure is, for example, a scale of 480 RGB × 640. In the display panel 2, gate electrodes G1 to G640 as scanning electrodes formed in the horizontal direction and drain electrodes D1 to D1440 as signal electrodes formed in the vertical direction are arranged, and selection terminals correspond to the intersections. A large number of display cells connected to the scan electrodes and having input terminals connected to the corresponding signal electrodes are arranged. The gate electrodes G1 to G640 are driven by applying pulses in the arrangement order of the electrodes, for example.

  FIG. 4 illustrates the overall configuration of the touch sensor panel controller 3. The touch sensor panel controller 1 includes a drive circuit (YDRV) 300, an integration circuit (INTGR) 301 as a detection circuit, a sample hold circuit (SH) 302, a selector (SLCT) 303, an AD conversion circuit (ADC) 304, a RAM 305, and a bus interface. A circuit (BIF) 306 and a sequence control circuit (SQENC) 308 are included.

  The drive circuit 300 drives the Y electrodes Y1 to YM with a pulsed AC drive voltage in the order of electrode arrangement. In short, the intersection capacitance is scan-driven. The integration circuit 301 inputs detection signals sequentially from the intersection capacitance driven by scanning and accumulates the signal charges. The selector 303 selects the charge signal integrated by the integration circuit for each X electrode (X1 to XN), and the selected charge signal is converted into detection data by the AD conversion circuit 304. The converted detection data is stored in the RAM 305. The detection data stored in the RAM 305 is supplied to the sub-system microphone processor 5 via the bus interface circuit 306 and used for digital filter calculation and coordinate calculation.

  The sequence control circuit 308 uses the control signals Csig1 to Csig6 to control the operations of the drive circuit 300, the integration circuit 301, the sample hold circuit 302, the selector 303, the AD conversion circuit 304, and the bus interface circuit 306, and also according to the control signal Csig7. Access control of the RAM 305 is performed. Although not particularly limited, a plurality of drive voltages Vbst output from the drive circuit 300 to the Y electrodes, an initialization voltage VHSP of the X electrodes input from the integration circuit 301, and other power supply voltages VIC are supplied from the outside of the touch sensor panel controller 3. Is done.

  FIG. 5 shows an example of an equivalent circuit of the touch sensor panel 1 and an integration circuit 301 as a detection circuit. In the touch sensor panel, Y electrodes Y1 to YM and X electrodes X1 to XN are arranged in a matrix, and an intersection capacitance Cxy as an intersection capacitance is formed at the intersection.

  The integration circuit 301 resets the power supply VHSP for charging the X electrodes X1 to XN, the switch SW2 for controlling the charging of the power supply VHSP to the X electrodes X1 to XN, the operational amplifier AMPit, the integration capacitor Cs, and the integration capacitor Cs. Switch SW1. The switch SW1 is a switch for resetting the electric charge superimposed on the capacitor Cs used for detection, and the switch SW2 is a switch for charging the power supply VHSP to the X electrodes X1 to XN.

  FIG. 6 shows an example of an input waveform to the Y electrodes Y1 to YM. As illustrated in the figure, a pulsed AC driving voltage is input to the Y electrodes Y1 to YM in the order of electrode arrangement. In FIG. 6, the drive pulse signal is changed, for example, nine times per Y electrode.

  FIG. 7 illustrates the input pulse voltage to the Y electrodes Y1 to YM and the timing of the detection operation by the integration circuit 301. First, the switch SW2 is turned on to make a transition to the non-detection state a in which the X electrode Xn (n = 1 to N) is charged to the power supply VHSP, the switch SWS1 is turned on, and the capacitor Cs is reset. Next, the switch SW1 and the switch SW2 are turned off, and a transition is made to the detection standby state b. In the detection standby state b, the X electrode Xn is not connected to the power supply VHSP, and the voltage level is held in the integrating circuit 301 having a virtual ground configuration. Then, after transitioning to the detection standby state b, a rising pulse having an amplitude Vy is input to the Y electrode Y1 (the other Y electrodes Y2 to YM are fixed at a low level). As a result, the charge (= Vy × Cxy) is moved to the X electrode Xn via the intersection capacitance Cxy on the Y electrode Y1 and input to the detection circuit 301, and the output VOUTn of the operational amplifier AMPit changes. Note that when touched with a finger, the capacitance of the corresponding intersection is reduced by the capacitance value Cf with respect to the intersection capacitance Cxy. For example, if the touched X electrode is X2, the charge input to the operational amplifier AMPit of the X electrode X2 Becomes Vy × (Cxy−Cf), and the output VOUT2 of the operational amplifier AMPit is higher than that in the non-touch case. This VOUTn (n = 1 to N) is converted into detection data of a digital value by the AD conversion circuit 304 and used for coordinate calculation or the like.

  FIG. 8 illustrates an equivalent circuit of the liquid crystal display panel 2 and a liquid crystal driver 4 drive circuit. In the liquid crystal display panel 2, gate electrodes G1 to G640 and drain electrodes D1 to D1440 are arranged in a matrix, and TFT (Thin Film Transistor) switches are formed at the intersections. A liquid crystal pixel electrode S of a liquid crystal capacitor LCD serving as a subpixel is connected to the source side of the TFT switch, and an electrode on the opposite side of the liquid crystal capacitor LCD is a common electrode (COM). The drain electrodes D1 to D1440 are coupled to the output of an operational amplifier AMPvf that constitutes a voltage follower. For example, the gradation voltage VDR1 corresponding to red is supplied to the operational amplifier AMPvf of the drain electrode D1, and the gradation voltage VDG1 corresponding to green is supplied to the operational amplifier AMPvf of the drain electrode D2.

  FIG. 9 illustrates input waveforms to the gate electrodes G1 to G640. Gate pulses are input to the gate electrodes G1 to G640 in a line sequential manner.

  FIG. 10 illustrates timing waveforms of the gate pulse applied to the gate electrode and the gradation voltage applied to the drain electrode. For example, a gate pulse with an amplitude Vg is input to the gate electrode G1, and the TFT switch on the gate electrode G1 is turned on. Thereafter, the gradation voltage VDR1 is applied from the drain electrode D1 to the selected liquid crystal pixel electrode S through the TFT switch. The input voltage of the liquid crystal pixel electrode S is determined at the timing when the gate pulse falls. A reference voltage is applied to the common electrode COM, and after the TFT switch is turned off, the reference voltage COM and the gradation voltage VDR1 are held in the liquid crystal capacitor LCD for one frame to define display luminance.

  Next, the drive pulse waveform of the Y electrode by the drive circuit 300 will be described. The drive waveforms of the Y electrodes Y1 to YM shown in FIGS. 6 and 7 are shown as simple rectangular waveforms for convenience, but in reality, the drive waveforms are controlled so that the waveform during the rise and fall can be varied. The The control is performed by the sequence control circuit 308 with the control signal Csig1 in accordance with the waveform mode set in the control register CREG 320 by the subsystem microprocessor 5.

  Here, making the waveform during the rise and fall of the drive waveform variable means, for example, making the waveform slope and the intermediate voltages V1 and V2 of the slope variable as shown by a broken line with respect to the solid line shown in FIG. In addition, as indicated by the broken line illustrated in FIG. 12, the switching timings T1, T2, and T3 with respect to the waveform inclination are made variable.

  FIG. 13 shows a configuration example of the output waveform variable selection unit in the drive circuit. Although not particularly limited, a variable selection unit 310 is arranged for each of the Y electrodes Y1 to YM, and each variable selection unit 310 has a ground voltage GND, a positive voltage VH with respect to the ground voltage GND, and a voltage with respect to the ground voltage GND. A negative voltage VL is commonly supplied. Although the negative voltage VL and the positive voltage VH are not particularly limited, they are variable voltages determined according to the waveform mode.

  The variable selection unit 310 has switches SW1 to SW5 and a resistance element R, and supplies the drive voltage selected by one of the switches SW1 to SW3 to the corresponding Y electrode as it is, or is selected by the switch SW4 or SW5. The drive voltage thus supplied is supplied to the corresponding Y electrode via the resistance element R. The switches SW1 to SW5 are alternatively selected by clock signals SCK1 to SCK5. The clock signals SCK1 to SCK5 are generated by the sequence control circuit 308 in accordance with the waveform mode set in the control register 320. For example, the sequence control circuit 308 can generate the clock signals SCK1 to SCK5 using its timer counter function or PWM (Pulse-width modulation) function.

  FIG. 14 shows an example of a pulse waveform generated via the variable selection unit 310. Here, the peak value of the drive signal is VH−VL, and at each pulse period, VL selection is switched to GND selection at time t0, GND selection is switched to VH selection at time t1, and VH selection is switched to GND selection at time t2. By switching and switching from GND selection to VL selection at time t3, the illustrated waveform is formed. Various waveforms can be selected by switching the selection timing of the voltages VL, GND, and VH and by changing the values of the voltages VL and VH. Furthermore, the slopes of the rising waveform and the falling waveform are larger when the switches SW4 and SW5 are selected than when the switches SW1 and SW3 are selected. In particular, in the example of FIG. 14, the switch SW4 is selected at time t1 to reduce the inclination at the time of rising, and the switch SW5 is selected at time t3 to decrease the inclination at the time of falling. Further, by selecting the switch SW1 at time t1 at the time of rising and switching to the switch SW4 in the middle, the change in the pulse shape is further moderated. Similarly, at the time t3, the switch SW3 is selected at the time t3 and switched to the switch SW5 in the middle. It is also possible to make the pulse shape change more gradual by switching.

  FIG. 15 schematically shows the influence of the drive waveform of the Y electrode on the liquid crystal display panel 2. Ry is the distributed wiring resistance of the Y electrode Yn, and Cxy is the intersection capacitance. Ccp means a distributed coupling capacitance between the liquid crystal display panel 2 and the touch sensor panel 1. For example, when the Y electrode Yn is driven by the drive pulse having the pulse waveform DW0 of FIG. 14 from its starting edge, the pulse waveform gradually becomes dull like DW1, DW2, Dw3 as it approaches the end of the Y electrode Yn. Becomes larger. This pulse waveform is propagated to the liquid crystal display panel 2 as noise waveforms NW1, NW2, and NW3 through the distributed coupling capacitance Ccp. As is clear from the waveform of FIG. 15, the pulse waveform of the drive pulse has a small slope from the middle when rising, and a small slope from the middle when falling, so that the noise waveforms NW1 to NW3 can be kept small. In addition, the difference in magnitude between the noise waveforms NW1 to NW3 is also reduced.

  Therefore, the rising and falling waveform of the driving pulse signal can be set variably according to the characteristics of the liquid crystal display panel 2 and the like affected by noise, so that the rising and falling of the pulse driving voltage with respect to the Y electrode can be set. It is possible to reduce the influence of noise caused by.

  On the other hand, when the drive pulse waveform for the Y electrode is generated only by the positive voltage VH and the ground voltage GND as illustrated in FIG. 19, the pulse waveform is a simple rectangular pulse waveform as illustrated in FIG. It is said. The pulse waveforms DW21, DW22, and DW23 in which the pulse waveform DW20 is sequentially propagated from the beginning of the Y electrode Yn are given to the liquid crystal display panel 2 as noise waveforms NW21, NW22, and NW23 via the distributed coupling capacitance Ccp. As is clear from the waveform of FIG. 21, the pulse waveform DW20 of the drive pulse is a simple rectangular pulse waveform unlike the case of FIG. 15, and the peak value of the noise waveform increases as the drive source of the Y electrode Yn is closer. Further, the noise waveforms NW11 and NW23 are greatly different from each other at both ends of the Y electrode Yn. In this way, if the distribution of the noise waveform given to one liquid crystal display panel is greatly different depending on the location and the maximum value is also increased, it is considered that the display state of the liquid crystal display panel becomes large and the display performance is significantly deteriorated. . When the touch sensor panel controller 3 of the present embodiment is used, the influence of such noise on the liquid crystal display panel 2 can be reduced and further suppressed as is apparent from the above.

  Next, a drive circuit 300A according to a modification of the drive circuit 300 will be described.

  FIG. 16 illustrates another configuration of the output waveform variable selection unit in the drive circuit 300A and the configuration of the power supply circuit used therefor. Although not particularly limited, a variable selection unit 310A is arranged for each of the Y electrodes Y1 to YM, and voltages VLL, VL, VH, and VHH are sequentially supplied from the low level to the high level in common to each variable selection unit 310A. Is done.

  Voltages VLL, VL, VH. VHH is not particularly limited, but is a variable voltage determined according to the waveform mode, and is generated by the power supply circuit 330. For example, for the voltage VHH, the reference voltage Vref is input to the non-inverting input terminal (+), and the output is divided and fed back to the inverting input terminal (−) by the variable resistance circuit 341 and the resistance element 351. The operational amplifier 331 outputs a positive high voltage corresponding to the set resistance value 341. As for the voltage VH, the reference voltage Vref is input to the non-inverting input terminal (+), and the output is divided and fed back to the inverting input terminal (−) by the variable resistance circuit 342 and the resistance element 352. The operational amplifier 332 outputs a positive voltage corresponding to the set resistance value. As the voltage VL, the ground voltage GND is input to the non-inverting input terminal (+), and the output is divided between the inverting input terminal (−) and the reference voltage Vref by the variable resistance circuit 343 and the resistance element 353. The operational amplifier 333 is fed back and outputs a negative voltage corresponding to the set resistance value of the variable resistance circuit 343. The voltage VLL is obtained by inputting the ground voltage GND to the non-inverting input terminal (+), and the output of the inverting input terminal (−) is divided between the reference voltage Vref and the variable resistance circuit 344 and the resistance element 354. The operational amplifier 334 is fed back and outputs a negative low voltage corresponding to the set resistance value of the variable resistance circuit 344.

  The variable selection unit 310A includes switches SW11 to SW14, and the drive voltage selected by one of the switches SW11 to SW14 is supplied to the corresponding Y electrode. The switches SW11 to SW14 are alternatively selected by clock signals SCK11 to SCK14. The clock signals SCK11 to SCK14 are generated by the sequence control circuit 308 according to the waveform mode set in the control register 320. For example, the sequence control circuit 308 can generate the clock signals SCK11 to SCK14 using its timer counter function or PWM (Pulse-width modulation) function.

  FIG. 17 shows an example of a pulse waveform generated via the variable selection unit 310 </ b> A and the power supply circuit 330. Here, the peak value of the drive signal is VHH-VLL, and at each pulse period, VL selection is switched to VHH selection at time t0, VHH selection is switched to VH selection at time t1, and VH selection is switched to VLL selection at time t2. The waveform shown in the figure is formed by performing switching and switching from VLL selection to VL selection at time t3. Various waveforms can be selected by switching the selection timing of the voltages VL, VHH, VH, and VLL and by changing the resistance value settings of the variable resistance circuits 341 to 344. In particular, in the example of FIG. 17, overdrive is performed after overdriving from the voltage VL to the voltage VHH at the rise and then stabilizing to the voltage VH, and at overfalling from the voltage VH to the voltage VLL and then stabilizing to the voltage VL. It is.

  FIG. 18 schematically shows the influence of the drive waveform of the Y electrode on the liquid crystal display panel 2. Ry is the distributed wiring resistance of the Y electrode Yn, and Cxy is the intersection capacitance. Ccp means a distributed coupling capacitance between the liquid crystal display panel 2 and the touch sensor panel 1. For example, when the Y electrode Yn is driven by the drive pulse having the pulse waveform DW10 of FIG. 18 from the starting end, the pulse waveform gradually becomes dull like DW11, DW12, Dw13 as it approaches the end of the Y electrode Yn. Becomes larger. However, the dullness is gentler than that of FIG. 15 due to the overdrive. This pulse waveform is propagated as noise waveforms NW11, NW12, and NW13 to the liquid crystal display panel 2 through the distributed coupling capacitor Ccp. As apparent from the waveform of FIG. 18, the Y electrode Yn is overdriven, and as a result, the propagation waveform of the Y electrode Yn is less dull than a simple rectangle, and the difference in dullness is different from that of the Y electrode Yn. Compressed at both ends. Therefore, even if the noise waveforms NW11 to NW13 increase as a whole, the difference in magnitude between the noise waveforms NW11 to NW13 is reduced compared to FIG. 15 and FIG.

  In this way, the waveform of the rise and fall of the drive pulse signal of the Y electrode can be variably set according to the characteristics of the liquid crystal display panel 2 and the like affected by noise, and overdrive driving is performed. It is possible to make the influence of noise caused by the rise and fall of the pulse drive voltage with respect to the Y electrode uniform along the Y electrode. That is, if the distribution of the noise waveform given to one liquid crystal display panel is made uniform depending on the location, even if the noise peak value is large, there will be no large spots in the display state of the liquid crystal display panel. Therefore, it is possible to suppress the deterioration of display performance remarkably.

  Although the invention made by the present inventor has been specifically described based on the embodiments, it is needless to say that the present invention is not limited thereto and can be variously modified without departing from the gist thereof.

  For example, the touch sensor panel controller may include a subsystem microprocessor on the same semiconductor chip and may be configured as a single chip. Further, the touch sensor panel controller may be configured as a single chip by providing a liquid crystal display driver on the same semiconductor chip in addition to a microprocessor as a subsystem data processor. Further, the touch sensor panel controller may include a liquid crystal display driver on the same semiconductor chip and may be configured as a single chip.

  Further, an AD conversion circuit may be provided for each X electrode. In that case, the sample hold circuit and the selector are unnecessary. Further, the pulse waveform for driving the Y electrode is not limited to the above waveform and can be changed as appropriate, and the type of drive voltage used therefor can be changed as appropriate. In addition, the variable selection units 310 and 310A as the switch circuits are arranged for each Y electrode. However, a common one is provided for each of the Y electrodes Y1 to YM, and the Y electrode that supplies the voltage selected by the selection unit is selected by the selector. You may make it do.

1 Touch sensor panel (TP)
2 Liquid crystal display panel (DSP)
3 Touch sensor panel controller (TPC)
4 Liquid crystal driver (DSPD)
5 Microprocessor for subsystem (SMPU)
6 Host processor (HMPU)
Y1 to YM Y electrode X1 to XN X electrode Cxy Intersection capacitance 300, 300A Drive circuit 301 Integration circuit (INTGR) as a detection circuit
308 Sequence control circuit (SQENC)
320 Control register 310 Variable selection unit GND Ground voltage VH Positive voltage VL Negative voltage SW1 to SW5 Switch R Resistance element SCK1 to SCK5 Clock signal 310A Variable selection unit VLL, VL, VH, VHH Voltage from low level to high level sequentially 330 Power supply Circuits 341 to 344 Variable resistance circuits 351 to 354 Resistive elements 331 to 334 Operational amplifier

Claims (13)

A drive circuit for driving the Y electrode of the touch sensor panel in which a plurality of capacitances at intersections are formed by the plurality of Y electrodes and the X electrodes;
A detection circuit that measures the capacitance value of the capacitance at the intersection through the X electrode;
A control circuit for controlling the drive circuit and the detection circuit,
The drive circuit is a touch sensor panel controller that outputs a drive pulse signal in which a waveform during rising and falling is variably set to a Y electrode based on control by the control circuit. The drive circuit includes a switch circuit that selects a required drive voltage from a plurality of drive voltages,
The touch sensor panel controller according to claim 1, wherein the control circuit generates a switch control signal of the switch circuit according to an instructed waveform mode. The drive circuit includes a switch circuit that selects a required drive voltage from a plurality of drive voltages and selects an output resistance value of the drive voltage;
The touch sensor panel controller according to claim 1, wherein the control circuit generates a switch control signal of the switch circuit according to an instructed waveform mode.   The switch circuit includes a plurality of first switches that arbitrarily select a ground voltage, a positive voltage with respect to the ground voltage, or a negative voltage with respect to the ground voltage, and output the Y voltage to the Y electrode, and optionally the positive voltage or the negative voltage. The touch sensor panel controller according to claim 3, further comprising: a plurality of second switches that select and output to the Y electrode via a resistance element. The switch circuit includes a plurality of switches for selecting a first voltage, a second voltage, a third voltage, and a fourth voltage sequentially from a low level to a high level,
The touch sensor panel controller according to claim 2, wherein the control circuit sequentially controls the second voltage selection, the fourth voltage selection, the third voltage selection, and the first voltage selection in units of a pulse period of the drive pulse.   The touch sensor panel controller according to claim 2, wherein the control circuit includes a control register in which a waveform mode is rewritable.   The touch sensor panel controller according to claim 6, further comprising a microprocessor that performs setting of a waveform mode for the control register and data processing using a detection result by the detection circuit. A touch sensor panel in which a plurality of intersection capacitances are formed by a plurality of Y electrodes and X electrodes;
A touch sensor panel controller that drives the Y electrode of the touch sensor panel and measures a capacitance value at each intersection of the Y electrode and the X electrode via the X electrode;
A microprocessor for performing data processing based on distribution data of capacitance values for each intersection of the Y electrode and the X electrode transferred from the touch sensor panel controller,
The touch sensor panel controller drives a Y electrode by outputting a drive pulse signal in which a waveform during rising and falling is variably set based on a waveform mode instructed by the microprocessor.   The touch sensor panel controller includes a switch circuit that selects a required drive voltage from a plurality of drive voltages, and generates a switch control signal of the switch circuit according to a waveform mode instructed by the microprocessor. The touch detection device according to claim 8. The touch sensor panel controller includes a switch circuit that selects a required drive voltage from a plurality of drive voltages and selects an output resistance value of the drive voltage, and the switch circuit according to a waveform mode instructed by the microprocessor The touch detection device according to claim 8, wherein the switch control signal is generated.   The switch circuit includes a plurality of first switches that arbitrarily select a ground voltage, a positive voltage with respect to the ground voltage, or a negative voltage with respect to the ground voltage, and output the Y voltage to the Y electrode, and optionally the positive voltage or the negative voltage. The touch detection device according to claim 10, further comprising: a plurality of second switches that select and output to the Y electrode via a resistance element. The switch circuit includes a plurality of switches for selecting a first voltage, a second voltage, a third voltage, and a fourth voltage, which sequentially go from a low level to a high level.
10. The touch detection device according to claim 9, wherein the touch sensor panel controller sequentially controls the second voltage selection, the fourth voltage selection, the third voltage selection, and the first voltage selection in units of a pulse period of the drive pulse. The touch sensor panel controller has a control register in which a waveform mode is set so as to be rewritable,
The touch detection device according to claim 8, wherein the microprocessor sets a waveform mode for the control register.

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