Touch panel device

Abstract

A touch panel device is provided. The touch panel device includes a plurality of first electrode lines, a plurality of second electrode lines, a drive signal generation circuit, a sensing signal reception circuit, and a drive signal amplification circuit. The plurality of first electrode lines extend in a first direction. The plurality of second electrode lines extend in a second direction intersecting the first direction. The drive signal generation circuit inputs a drive signal to each of the plurality of first electrode lines. The sensing signal reception circuit receives a sensing signal output from each of the plurality of second electrode lines and corresponding to a size of an electrostatic capacitance of each intersection of the plurality of first electrode lines and the plurality of second electrode lines. The drive signal amplification circuit amplifies the drive signal input to each of the plurality of first electrode lines. The drive signal amplified by the drive signal amplification circuit is input to the first electrode line.

Description

TECHNICAL FIELD

[0001] The present application relates to a touch panel device. BACKGROUND

[0002] A certain touch panel includes a plurality of first electrodes, a plurality of second electrodes, a capacitor, a signal generating circuit, and a detection circuit. The plurality of first electrodes and the plurality of second electrodes are orthogonal. The capacitor is formed at a portion where the first electrodes and the second electrodes cross each other. The signal generating circuit sequentially supplies a signal to one of the first electrodes and the second electrodes. The detection circuit detects a change in capacitance of the capacitor, amplifies and outputs a detection signal corresponding to the change in capacitance. SUMMARY

[0003] In a case where a touch operation causes a small change in electrostatic capacitance, there is a problem that the detection signal strength included in the detection signal is relatively small with respect to noise, and the detection accuracy of the touch operation is reduced due to the noise. However, the detection circuit of the touch panel described in Patent Document 1 amplifies both the signal and the noise included in the detection signal. That is, the detection circuit of the touch panel described in Patent Document 1 cannot improve the detection accuracy reduced due to the noise.

[0004] The present application has been achieved in view of the above-described problems, and an object thereof is to provide a touch panel device capable of improving detection accuracy.

[0005] According to an aspect of the present application, a touch panel device includes a plurality of first electrode lines, a plurality of second electrode lines, a drive signal generating circuit, a sensing signal receiving circuit, and a drive signal amplifying circuit. The plurality of first electrode lines extends in a first direction. The plurality of second electrode lines extends in a second direction intersecting the first direction. The drive signal generating circuit inputs a drive signal to each of the plurality of first electrode lines. The sensing signal receiving circuit receives a sensing signal output from each of the plurality of second electrode lines and corresponding to a size of an electrostatic capacitance of each intersection of the plurality of first electrode lines and the plurality of second electrode lines. The drive signal amplifying circuit is interposed between the drive signal generating circuit and the first electrode lines, and amplifies the drive signal input to each of the plurality of first electrode lines, respectively. The drive signal amplified by the drive signal amplifying circuit is input to the first electrode lines.

[0006] According to the touch panel device of the present application, it is possible to improve the detection accuracy. BRIEF DESCRIPTION OF DRAWINGS

[0007] Figure 1 is a block diagram showing a configuration of a touch panel device according to an embodiment of the present application.

[0008] Figure 2 is a schematic view showing a configuration of a touch panel provided in the touch panel device according to the present embodiment.

[0009] Figure 3 It is an explanatory diagram showing a schematic configuration of a touch panel according to this embodiment.

[0010] Figure 4 2 is a diagram showing a drive signal amplifier circuit according to this embodiment.

[0011] Figure 5 This is a table showing the pulse waveform of the drive signal before the pulse waveform is changed.

[0012] Figure 6 This is a table showing the pulse waveform of the driving signal after the pulse waveform deformation circuit has changed it. DETAILED DESCRIPTION

[0013] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In the drawings, identical or corresponding parts are denoted by identical reference numerals and their description will be omitted.

[0014] Reference Figure 1 Figure 4 A touch panel device 100 according to an embodiment of the present invention will be described. Figure 1 It is a block diagram showing the configuration of a touch panel device 100 according to an embodiment of the present invention. Figure 2 2 is a schematic diagram showing the configuration of the touch panel 20 provided in the touch panel device 100 . Figure 3 It is an explanatory diagram showing a schematic configuration of the touch panel 20 . Figure 4 3 is a diagram showing the drive signal amplifying circuit 36 ​​.

[0015] like Figures 1 to 3 As shown, the touch panel device 100 includes a display 10 , a touch panel 20 , and a touch position determination circuit 30 .

[0016] The display 10 includes a display panel (e.g., a liquid crystal panel) that displays images. Furthermore, the touch panel device 100 may not include the display 10, but may only include the touch panel 20 and the touch position determination circuit 30. In other words, the touch panel device 100 only needs to have at least the touch panel function, and the touch panel 20 may not have the image display function of displaying images.

[0017] like Figure 2 As shown, the touch panel 20 includes a touch surface 21 , a plurality of first electrode lines HL, a plurality of second electrode lines VL, and a plurality of electrostatic capacitors.

[0018] The touch surface 21 receives touch operations. The touch surface 21 may be, for example, a touch surface of an electronic blackboard, or a touch surface of a terminal such as a smartphone or a tablet PC (Personal Computer).

[0019] A plurality of first electrode lines HL are arranged on the back side of the touch surface 21. The plurality of first electrode lines HL extend in the first direction. The plurality of first electrode lines HL extend in the first direction and are arranged in parallel with each other in the first direction. The plurality of first electrode lines HL include a first electrode line HLI to a first electrode line HLM.

[0020] A plurality of second electrode lines VL are arranged on the back side of the touch surface 21. The plurality of second electrode lines VL extend in the second direction. Specifically, the plurality of second electrode lines VL extend in the second direction and are arranged in parallel with each other in the second direction. The second direction indicates a direction intersecting the first direction. Specifically, the second direction indicates a direction perpendicularly intersecting the first direction.

[0021] The plurality of second electrode lines VL include a second electrode line VLI to a second electrode line VLM. The second electrode lines VLI to VLM are arranged so as to cross the first electrode lines HLI to HLM and the plurality of intersection points DIl to DMM.

[0022] The plurality of electrostatic capacitors include an electrostatic capacitor CIl to an electrostatic capacitor CMM. The electrostatic capacitors CIl to CMM are respectively formed at the intersection points DIl to DMM of the first electrode lines HLI to HLM and the second electrode lines VLI to VLM.

[0023] The touch panel 20 including the first electrode line group H and the second electrode line group V is fixedly attached to the display 10 or a protective glass not shown. The second electrode line group V is arranged on a side closer to the display 10 than the first electrode line group H. Further, the first electrode line group H can also be arranged on a side closer to the display 10 than the second electrode line group V. Further, in practice, a PET film is provided between the first electrode line group H, the second electrode line group V, and the display 10, but is omitted from the description of Figure 3

[0024] The touch position determination circuit 30 is constituted by, for example, a semiconductor element (CPU, memory, etc.), a resistor, a capacitor, a coil, or the like. The touch position determination circuit 30 determines a touch position indicating a touched position on the touch surface 21 by detecting a distribution of values of the electrostatic capacitors CIl to CMM respectively formed at the intersection points DIl to DMM of the first electrode lines HLI to HLM and the second electrode lines VLI to VLM on the touch panel 20.

[0025] When a touch operation is performed on the touch surface 21, the intersection points DIl to DMM of the first electrode lines HLI to HLM and the second electrode lines VLI to VLM are touched. The electrostatic capacitors CIl to CMM respectively formed at the intersection points DIl to DMM are changed in value. The touch position determination circuit 30 detects the distribution of values of the electrostatic capacitors CIl to CMM. ​The electrostatic capacitance of the intersection points DMM located around the position where the touch operation was performed changes. As a result, the touch position determination circuit 30 determines the touch position on the touch surface 21 based on the change in electrostatic capacitance.

[0026] The touch position determination circuit 30 includes a drive signal generation circuit 31 , a sensing signal receiving circuit 32 , an AD converter 33 , a timing generator 34 , a detection unit 35 , a drive signal amplification circuit 36 ​​, a recording unit 38 , and a touch position determination unit 39 .

[0027] The drive signal generation circuit 31 inputs drive signals to each of the plurality of first electrode lines HL. The drive signal generation circuit 31 is connected to the first electrode lines HL1 to HLM via the drive signal amplifier circuit 36. The drive signal generation circuit 31 is connected to the drive signal amplifier circuit 36 ​​via the drive lines DL1 to DLM. The drive signal generation circuit 31 applies voltages to the first electrode lines HL1 to HLM via the drive lines DL1 to DLM, thereby inputting drive signals to each of the first electrode lines HL1 to HLM.

[0028] The induction signal receiving circuit 32 receives output signals from each of the plurality of second electrode lines VL. Specifically, the induction signal receiving circuit 32 receives induction signals corresponding to the magnitude of the electrostatic capacitance at each intersection between the plurality of first electrode lines HL and the plurality of second electrode lines VL. The induction signal receiving circuit 32 includes a MOSFET in its circuit.

[0029] More specifically, the induction signal receiving circuit 32 detects induction signals from the second electrode lines VL1 through VLM via the induction lines SL1 through SLM, and reads capacitance information corresponding to each capacitance (each of capacitances C11 through CMM). This capacitance information represents the linear sum of charges. The induction signal receiving circuit 32 then transmits the read capacitance information to the AD converter 33. As a result, the AD converter 33 acquires the capacitance information.

[0030] The AD converter 33 performs AD conversion on the electrostatic capacitance information acquired from the induction signal receiving circuit 32 and transmits the converted information to the detection unit 35. As a result, the detection unit 35 acquires the electrostatic capacitance information after the AD conversion.

[0031] Timing generator 34 controls drive signal generation circuit 31, touch position determination unit 39, and drive signal amplifier circuit 36. Timing generator 34 generates signals that define the operation of drive signal generation circuit 31, the operation of detection signal receiving circuit 32, and the operation of A / D converter 33, and transmits these signals to drive signal generation circuit 31, detection signal receiving circuit 32, and A / D converter 33.

[0032] The detection unit 35 calculates the capacitance distribution on the touch surface 21 based on the capacitance information and code sequence acquired from the AD converter 33. Specifically, the detection unit 35 detects a detection value (a change in capacitance) based on a change in capacitance (capacitance C11 to capacitance CMM) at each intersection (intersection D11 to intersection DMM) formed by the plurality of first electrode lines HL (first electrode lines HL1 to first electrode lines HLM) and the plurality of second electrode lines VL (second electrode lines VL1 to second electrode lines VLM).

[0033] The detection unit 35 transmits the detection value (information indicating the electrostatic capacitance distribution) to the touch position determination unit 39 . As a result, the touch position determination unit 39 acquires the detection value of the detection unit 35 .

[0034] Touch position determination unit 39 is electrically connected to induction signal receiving circuit 32 via A / D converter 33 and detection unit 35. Touch position determination unit 39 detects a touch on touch surface 21 based on changes in the output signal detected by induction signal receiving circuit 32 due to changes in the electrostatic capacitance between intersection D11 and intersection DMM. For example, touch position determination unit 39 determines the touch position on touch surface 21 based on the distribution of detection values ​​for the coordinates of multiple intersections (intersection D11 to intersection DMM) detected by detection unit 35 and the determination conditions recorded by recording unit 38.

[0035] The recording unit 38 records the determination condition. The determination condition indicates information used by the touch position determination unit 39 to determine the touch position on the touch surface 21.

[0036] like Figure 3 As shown, the touch surface 21 includes a first area A1, a second area A2, and a third area A3. The drive signal generated by the drive signal generation circuit 31 is connected to the connection terminal provided in the first area A1 via a cable connected to the first electrode wire group H. The drive signal input to the first electrode wire group H is input to each first electrode wire HL in the first area A1, second area A2, and third area A3 via the peripheral wiring (routing wires) of the first electrode wire group H (not shown). The wiring length of the peripheral wiring varies for each first electrode wire HL depending on the length of the routing wires. The wiring length is shortest in the first area A1, closest to the terminal, second shortest in the second area A2, and longest in the third area A3, farthest from the terminal. Furthermore, since the longer the terminal, the larger the inherent time constant of the wiring, the wiring has different time constants in each area, increasing in order from the first area A1 to the second area A2 to the third area A3.

[0037] Generally, the size of noise (background noise) is a fixed value, and the smaller the change in electrostatic capacity based on the touch operation (signal strength) is, the smaller the change ratio of the change in electrostatic capacity based on the touch operation with respect to the noise contained in the induced signal is, and the smaller the signal-noise ratio (SN ratio) of the induced signal is. Therefore, in particular, in a case where the touch is performed in a hovering state at a distance from the touch surface 21, in a case where a non-electric medium is used for the touch operation, and the like, the change in electrostatic capacity caused by the touch operation is small, there is a tendency that the signal-to-noise ratio of the induced signal decreases. When the signal-to-noise ratio of the induced signal decreases, the change in electrostatic capacity based on the touch operation is submerged in the noise, and it is difficult to detect the touch operation, and the detection accuracy decreases. The size of the change in electrostatic capacity based on the touch operation is such that the size of the drive signal becomes large. Therefore, by amplifying the drive signal, it is possible to improve the signal-to-noise ratio of the induced signal.

[0038] The drive signal amplification circuit 36 amplifies the drive signal. Specifically, the drive signal amplification circuit 36 amplifies the drive signal input to each of the plurality of first electrode lines HL. The drive signal amplification circuit 36 is interposed between the drive signal generation circuit 31 and the first electrode line HL. That is, the drive signal amplified by the drive signal amplification circuit 36 is input to the first electrode line HL. Therefore, since the drive signal before input to the first electrode line HL is amplified, it is possible to increase the signal-to-noise ratio (SN ratio). As a result, even in a case where the signal-to-noise ratio (SN ratio) is relatively small, it is possible to improve the detection accuracy.

[0039] In a case where the induced signal output from the second electrode line is amplified, the noise contained in the induced signal is also amplified, and therefore it is not possible to improve the signal-to-noise ratio. On the other hand, in the present embodiment, the drive signal is amplified, and the noise contained in the induced signal is not amplified. Therefore, it is possible to increase the signal-to-noise ratio (SN ratio) of the electrostatic capacity information with respect to the noise. As a result, even in a case where the change in electrostatic capacity caused by the touch operation is small in a normal case, it is possible to increase the change in electrostatic capacity caused by the touch operation, and therefore it is possible to reduce the deterioration of the detection accuracy due to the noise.

[0040] As Figure 4As shown, the drive signal amplifying circuit 36 ​​is composed of an analog amplifier circuit. The analog amplifier circuit amplifies the input signal of the voltage VCC. Specifically, the analog amplifier circuit amplifies the input signal of the maximum voltage VCC to the maximum voltage VDD. The drive signal amplifying circuit 36 ​​is a non-inverting amplifier circuit. The drive signal amplifying circuit 36 ​​includes an operational amplifier OP, a resistor R1 and a resistor R2. The operational amplifier OP has a non-inverting input terminal (+) and an inverting input terminal (-). The output of the second pulse waveform deformation circuit 37B described later is connected to the non-inverting input terminal (+) of the operational amplifier OP. The output of the operational amplifier OP is connected to the first pulse waveform deformation circuit 37A described later. Moreover, the output of the operational amplifier OP is connected to the inverting input terminal (-) via the resistor R2. The resistor R1 is connected between the inverting input terminal (-) of the operational amplifier OP and the ground.

[0041] Next, refer to Figure 1 Figure 4 The touch panel device 100 will be described in detail. The touch panel device 100 further includes a pulse waveform deformation circuit 37. The pulse waveform deformation circuit 37 deforms the pulse waveform. The drive signal is a pulse signal. The pulse waveform deformation circuit 37 is configured to correspond to each drive signal input to the plurality of first electrode lines HL. The pulse waveform deformation circuit 37 deforms the pulse waveform of each drive signal so that the pulse rise time is increased, either before or after the drive signal is amplified by the drive signal amplifier 36, or both. This prevents the pulse signal from becoming steep due to a short pulse rise time.

[0042] The inventors have discovered that, through verification, when the drive signal is amplified solely by the drive signal amplifier circuit 36, the pulse rise time of the amplified drive signal becomes shorter and more abrupt than before amplification. This results in a higher leakage current from the parasitic diode formed in the induction signal receiving circuit 32 than before amplification, leading to a new problem in which the detection signal value (detection value) is lower than expected. Furthermore, there is a tendency for the pulse rise time to increase as the wiring length from the drive signal generating circuit 31 to the first electrode line HL is shorter, and for the pulse rise time to decrease as the wiring length is longer. Because the drop in the detection signal value increases as the wiring length from the drive signal generating circuit 31 to the first electrode line HL is longer, it has been discovered that this can cause discrepancies in the detection values ​​within the touch panel device 100. The pulse waveform deformation circuit 37 described above is designed to address these issues. These issues will be described in detail later.

[0043] Since the pulse waveform deformation circuit 37 increases the pulse rise time, even when the drive signal amplification circuit 36 ​​amplifies the voltage value of the drive signal to the tolerance limit of the induction signal receiving circuit 32, the leakage current generated in the induction signal receiving circuit 32 can be reduced. Furthermore, by reducing the leakage current generated in the induction signal receiving circuit 32, a decrease in the detection value of the induction signal can be suppressed.

[0044] The longer the wiring length from the drive signal generation circuit 31 to the first electrode lines HL, the less the pulse rise time is increased by the pulse waveform deformation circuit 37. Specifically, with respect to each drive signal input to the plurality of first electrode lines HL, the longer the wiring length from the drive signal generation circuit 31 to the first electrode lines HL, the less the pulse rise time is increased by the pulse waveform deformation circuit 37.

[0045] Therefore, variations in the rise time of the pulse waveform caused by the length of the wiring connected to the first electrode lines HL can be suppressed. In other words, the sum of the pulse rise time caused by the pulse waveform deformation circuit 37 and the pulse rise time caused by the wiring is constant for each of the plurality of first electrode lines HL. As a result, variations in the detected values ​​of the induction signals can be suppressed.

[0046] like Figure 4 As shown, the pulse waveform deformation circuit 37 includes a first pulse waveform deformation circuit 37A and a second pulse waveform deformation circuit 37B.

[0047] The first pulse waveform deformation circuit 37A deforms the pulse waveform of the drive signal after amplification by the drive signal amplifier circuit 36. The first pulse waveform deformation circuit 37A is interposed between the drive signal amplifier circuit 36 ​​and each of the plurality of first electrode lines HL. This prevents the drive signal waveform from becoming steeper and increasing leakage current from the parasitic diode formed in the sensing signal receiving circuit 32. Consequently, the generation of noise in each sensing signal can be suppressed.

[0048] like Figure 4 As shown, the first pulse waveform deformation circuit 37A includes multiple first resistors RA and multiple first input signal wiring lines IL1. Each of the multiple first resistors RA is connected in series with the first input signal wiring line IL1. The first resistor RA is arranged between the drive signal amplifier circuit 36 ​​and the first electrode line HL. Each of the multiple first input signal wiring lines IL1 is connected to the first resistor RA and the first electrode line HL. Therefore, the first pulse waveform deformation circuit 37A functions as a low-pass filter through the parasitic capacitance within the wiring and the first resistors RA. As a result, the first pulse waveform deformation circuit 37A can deform the pulse waveform while suppressing a decrease in the detection accuracy of the touch panel device 100.

[0049] If a capacitor is placed near a capacitive touch panel device, detection accuracy may decrease. Therefore, a low-pass filter including a capacitor is generally not placed near a touch panel device.

[0050] In this embodiment, the first pulse waveform deformation circuit 37A is connected to the first electrode line HL of the touch panel device 100. Specifically, the drive signal amplification circuit 36, the first pulse waveform deformation circuit 37A, and the first electrode line HL are connected in series. More specifically, the drive signal amplification circuit 36, the first resistor RA of the first pulse waveform deformation circuit 37A, and the first electrode line HL are connected in series. In other words, the first pulse waveform deformation circuit 37A of this embodiment functions as a low-pass filter and does not include a capacitor, so it can be configured near the touch panel device 100. Therefore, the first pulse waveform deformation circuit 37A can suppress a decrease in detection accuracy. As a result, the first pulse waveform deformation circuit 37A can deform the pulse waveform.

[0051] Each of the multiple first resistors RA has a resistance value corresponding to the degree to which it increases the pulse rise time. In other words, the resistance value of the first resistor RA is set according to the wiring length. Therefore, the resistance value of each of the multiple first resistors RA can be set so that the rise time of the pulse waveform does not vary. As a result, it is possible to further suppress the decrease in the detection value of the induction signal depending on the location of the touch position.

[0052] In the first pulse waveform deformation circuit 37A, the time constant is determined by the product of the parasitic capacitance within the circuit and the resistance value of the first resistor RA. Furthermore, in the first pulse waveform deformation circuit 37A, the time constant can be changed by changing the resistance value of the first resistor RA. Changing the time constant can change the rise time of the pulse waveform. Therefore, by changing the resistance value of the first resistor RA in each of the multiple first pulse waveform deformation circuits 37A, the time constants of the multiple first pulse waveform deformation circuits 37A can be set, thereby ensuring that the rise times of the pulse waveforms do not differ.

[0053] The second pulse waveform deformation circuit 37B deforms the waveform of the drive signal before amplification by the drive signal amplifier circuit 36. The second pulse waveform deformation circuit 37B is interposed between the drive signal generation circuit 31 and the drive signal amplifier circuit 36. Therefore, the waveform of the drive signal can be deformed to remove signal components that do not need to be amplified. As a result, the signal amplified by the drive signal amplifier circuit 36 ​​can be selected.

[0054] Second pulse waveform deformation circuit 37B includes a low-pass filter circuit that removes high-frequency components. This allows the waveform of the drive signal to be deformed to remove high-frequency components that do not need to be amplified. This results in more accurate detection of the induced signal.

[0055] The second pulse waveform deformation circuit 37B includes a second resistor RB, a capacitor C, and a second input signal line IL2 . The second input signal line IL2 is arranged between the drive signal generation circuit 31 and the drive signal amplification circuit 36 ​​.

[0056] The second resistor RB is arranged between the drive signal generating circuit 31 and the drive signal amplifying circuit 36. The second resistor RB is connected in series with the second input signal wiring IL2. In other words, the drive signal generating circuit 31, the second resistor RB and the drive signal amplifying circuit 36 ​​are connected in series.

[0057] Capacitor C is placed between drive signal generation circuit 31 and drive signal amplifier circuit 36. Capacitor C is connected in parallel with drive signal generation circuit 31. This allows the waveform of the drive signal to be deformed to exclude high-frequency components that do not need to be amplified. As a result, the induced signal can be detected with higher accuracy.

[0058] The second pulse waveform deformation circuit 37B has a time constant corresponding to the degree to which the pulse rise time is increased. The pulse rise time is modified based on the time constant. Therefore, the time constants of the multiple second pulse waveform deformation circuits 37B can be set so as to avoid differences in the rise time of the pulse waveform. As a result, it is possible to further suppress the decrease in the detection value of the induction signal depending on the location of the touch position.

[0059] The time constant can be changed by varying at least one of the capacitance of capacitor C and the resistance of second resistor RB. Specifically, the time constant can be set by varying at least one of the capacitance of capacitor C and the resistance of second resistor RB to achieve the pulse rise time desired by the designer. Furthermore, the time constant is determined by the product of the capacitance of capacitor C and the resistance of second resistor RB.

[0060] According to this embodiment, the drive signal generation circuit 31 outputs multiple drive signals. Furthermore, the second pulse waveform deformation circuit 37B deforms the waveforms of the multiple drive signals. Specifically, the second pulse waveform deformation circuit 37B removes high-frequency components from the multiple drive signals. Furthermore, the second pulse waveform deformation circuit 37B modifies the pulse rise time of the drive signals based on a time constant of the second pulse waveform deformation circuit 37B.

[0061] Next, the drive signal amplification circuit 36 ​​amplifies the multiple drive signals whose waveforms have been modified. This increases the signal-to-noise ratio (SN ratio). Then, the first pulse waveform deformation circuit 37A deforms the pulse waveforms of the multiple drive signals after amplification by the drive signal amplification circuit 36. Specifically, the first pulse waveform deformation circuit 37A deforms the pulse waveforms of the multiple drive signals so that there is no difference in the rise time of the pulse waveforms. Therefore, the decrease in the detection value of the induced signal can be reduced. As a result, the decrease in the detection accuracy of the touch operation can be reduced.

[0062] Next, refer to Figure 4 Figure 6 The pulse waveform deformation circuit 37 will be described in more detail.

[0063] Figure 5 Table G1 shows the pulse waveform of the drive signal when the pulse waveform deformation circuit 37 is not present. Table G1 includes a first column T1 Ninth column T9.

[0064] Figure 5 The first column T1, second column T2, and third column T3 shown are the input waveforms of the drive signals in the first area A1, second area A2, and third area A3, respectively. Furthermore, the waveforms in the first column T1, second column T2, and third column T3 are the waveforms before deformation due to the inherent time constant of the wiring. Specifically, they are the waveforms of the drive signals immediately after the drive signal generation circuit 31 generates the drive signals in the first area A1, second area A2, and third area A3. The waveforms in the first column T1, second column T2, and third column T3 are substantially identical (square waves). Furthermore, the rise times τ1, τ2, and τ3 of the waveforms in the first column T1, second column T2, and third column T3 are substantially identical, approximately zero.

[0065] Figure 5The fourth column T4, fifth column T5, and sixth column T6 show the waveforms of the drive signal input waveforms shown in the first column T1, second column T2, and third column T3 in the first, second, and third regions A1, A2, and A3, respectively, after being deformed due to the effect of the inherent time constant of the wiring. Specifically, these are the waveforms of the drive signal when it reaches the plurality of first electrode lines HL in the first, second, and third regions A1, A2, and A3. Compared to the waveforms in the first, second, and third columns T1, T2, and T3, the rise times of the waveforms in the fourth column T4, fifth column T5, and sixth column T6 increase from τ1, τ2, and τ3 to τ4, τ5, and τ6, respectively. Furthermore, the inherent time constant of the wiring increases in the order of the first region A1, second region A2, and third region A3. Therefore, the relationship between τ4, τ5, and τ6 is τ4 < τ5 < τ6. That is, the steepness of the rising waveform of the driving signal when it reaches the first electrode lines HL is the highest in the first region A1 , is medium in the second region A2 , and is the lowest in the third region A3 .

[0066] Figure 5 The seventh column, T7, the eighth column, T8, and the ninth column, T9, are the waveforms of the induced signals in the first area A1, the second area A2, and the third area A3, respectively. The waveform in the seventh column, T7, corresponds to the rising waveform in the fourth column, T4. After the induced signal reaches its first peak, the voltage decreases due to leakage current. The waveform corresponding to the fourth column, T4, has the steepest rising edge, and the leakage current reaches its maximum magnitude. The average voltage of the induced signal corresponding to the received strength of the induced signal is V9. The waveform in the eighth column, T8, corresponds to the rising waveform in the fifth column, T5. After the induced signal reaches its first peak, the voltage decreases due to leakage current. Corresponding to the moderate steepness of the rising waveform in the fifth column, T5, the leakage current is moderate, and the average voltage of the induced signal corresponding to the received strength of the induced signal is V8. Because the waveform in the sixth column, T6, has the lowest rising edge, the waveform in the ninth column, T9, barely reaches its initial peak, and the voltage drop due to leakage current is also minimal. The average voltage of the induced signal corresponding to the received strength of the induced signal is V9. As described above, the magnitude of the leakage current increases in the order of the first region A1, the second region A2, and the third region A3. Therefore, the magnitude relationship among V7, V8, and V9 is V7. <V8<V9的关系。即,感应信号的接收强度按第一区域A1、第二区域A2、第三区域A3的顺序变大,每个区域在感应信号的接收强度上产生差异。

[0067] Figure 6 Table G2 shows the pulse waveform of the drive signal when the pulse waveform deformation circuit 37 is provided. Table G2 includes the 11th column T11 to the 19th column T19.

[0068] Figure 6 Columns 11, 12, and 13 show the input waveforms of the drive signals in the first, second, and third regions A1, A2, and A3, respectively. The waveforms in columns 11, 12, and 13 are the waveforms before they are deformed due to the inherent time constant of the wiring. Specifically, columns 11, 12, and 13 show the waveforms immediately after the drive signal generation circuit 31 generates the drive signal and then the pulse waveform deformation circuit 37 deforms the drive signal. The longer the wiring length from the drive signal generation circuit to the first electrode line HL, the less the pulse rise time is increased by the pulse waveform deformation circuit 37. Therefore, the waveform rise times τ11, τ12, and τ13 in columns 11, 12, and 13 are related by the relationship τ11 > τ12 > τ13. That is, after the drive signal generating circuit 31 generates the drive signal and the pulse waveform deformation circuit 37 deforms the waveform of the drive signal, the third region A3 has the largest steepness, followed by the second region A2 which is medium, and the first region A1 has the smallest steepness.

[0069] Figure 6 The waveforms in columns 14, 15, and 16 are the waveforms of the drive signal input waveforms shown in columns 11, 12, and 13, respectively, in the first area A1, second area A2, and third area A3, after being deformed due to the inherent time constant of the wiring. Specifically, these are the waveforms of the drive signal arriving at the plurality of first electrode lines HL in the first area A1, second area A2, and third area A3. Compared to the waveforms in columns 11, 12, and 13, the rise times of the waveforms in columns 14, 15, and 16 are increased from τ11, τ12, and τ13 to τ14, τ15, and τ16, respectively. As a result, the rise times τ14, τ15, and τ16 of the waveforms in the fourteenth column T14, the fifteenth column T15, and the sixteenth column T16 respectively become substantially the same value.

[0070] Figure 6Columns 17 (T17), 18 (T18), and 19 (T19) show the waveforms of the induced signals in the first, second, and third areas A1, A2, and A3, respectively. The waveforms in columns 17 (T17), 18 (T18), and 19 (T19) have rise times τ14, τ15, and τ16 that are approximately the same as those in columns 14 (T14), 15 (T15), and 16 (T16), respectively, resulting in similar waveforms. Furthermore, because the leakage currents are approximately the same, the average voltage of the induced signals corresponding to the received signal strengths of the waveforms in columns 17 (T17), 18 (T18), and 19 (T19) is approximately the same. In other words, the received signal strengths are approximately the same across the first, second, and third areas A1, A2, and A3, with no difference in received signal strength between the areas.

[0071] Column 15 T15 and Figure 6 The 12th column T12 shown corresponds to the 15th column T15. Figure 3 The output waveform of the driving signal input to the plurality of first electrode lines HL corresponding to the second area A2 shown in FIG. The waveform of the driving signal is deformed by the pulse waveform deformation circuit 37 in such a way that the time constant becomes larger. In other words, the leakage current of the second area A2 becomes smaller. In the case of a large leakage current, such as Figure 6 As shown in the 15th column T15, the pulse rise time of the output waveform of the drive signal becomes longer. In other words, the pulse waveform of the output waveform of the drive signal becomes less steep.

[0072] Column 16 T16 and Figure 6 The 13th column T13 corresponds to the 16th column T16. Figure 3 The output waveform of the driving signal of the plurality of first electrode lines HL corresponding to the third area A3 shown in FIG. The waveform of the driving signal is deformed by the pulse waveform deformation circuit 37 in such a way that the time constant becomes larger. That is, the leakage current of the third area A3 becomes smaller. In the case of a large leakage current, such as Figure 6 As shown in the 16th column T16, the pulse rise time of the output waveform of the drive signal becomes longer. In other words, the pulse waveform of the output waveform of the drive signal becomes less steep.

[0073] The embodiments of the present invention have been described above with reference to the accompanying drawings. However, the present invention is not limited to the above-described embodiments and can be implemented in various ways without departing from the scope of the present invention. In the accompanying drawings, each component is schematically shown as a main body for easy understanding, and for the convenience of drawing, the number, spacing, etc. of each component shown in the drawings may be different from the actual ones. In addition, the components shown in the above-described embodiments are only examples and are not particularly limited. Various changes can be made within the scope of the effects of the present invention.

Claims

1. A touch panel device, characterized in that: include: a plurality of first electrode lines extending along a first direction; a plurality of second electrode lines extending along a second direction intersecting the first direction; a driving signal generating circuit for generating a driving signal input to each of the plurality of first electrode lines; an induction signal receiving circuit that receives an induction signal output from each of the plurality of second electrode lines and corresponding to a magnitude of an electrostatic capacitance of each intersection of the plurality of first electrode lines and the plurality of second electrode lines; as well as A driving signal amplifying circuit is interposed between the driving signal generating circuit and the first electrode line, and amplifies the driving signals input to the plurality of first electrode lines. inputting the drive signal amplified by the drive signal amplifying circuit to the first electrode line, The driving signal is a pulse signal, The touch panel device further includes a pulse waveform deformation circuit, the pulse waveform deformation circuit being arranged corresponding to each of the plurality of first electrode lines and deforming the pulse waveform of the pulse signal so as to increase the pulse rise time for each of the drive signals at least either before or after the drive signal amplification circuit amplifies the drive signal. For each of the drive signals input to the plurality of first electrode lines, the longer the wiring length from the drive signal generating circuit to the first electrode line, the less the extent to which the pulse waveform deformation circuit increases the pulse rise time.

2. The touch panel device according to claim 1, wherein: The pulse waveform deformation circuit includes a first pulse waveform deformation circuit, which is located between the drive signal amplification circuit and each of the first electrode lines and deforms the pulse waveform of the drive signal amplified by the drive signal amplification circuit.

3. The touch panel device according to claim 2, wherein: The first pulse waveform deformation circuit includes a plurality of first resistors connected in series with a first input signal wiring arranged between the drive signal amplification circuit and the first electrode line.

4. The touch panel device according to claim 3, wherein: Each of the plurality of first resistors has a resistance value corresponding to a degree of increase in the pulse rise time.

5. The touch panel device according to claim 1, wherein The pulse waveform deformation circuit includes a second pulse waveform deformation circuit, which is interposed between the drive signal generation circuit and the drive signal amplification circuit and deforms the waveform of the drive signal before amplification by the drive signal amplification circuit.

6. The touch panel device according to claim 5, wherein: The second pulse waveform deformation circuit is a low-pass filter circuit that removes high-frequency components.

7. The touch panel device according to claim 6, wherein: The second pulse waveform deformation circuit includes: a second resistor connected in series with a second input signal wiring arranged between the drive signal generating circuit and the drive signal amplifying circuit; and A capacitor is connected in parallel with the drive signal generating circuit.

8. The touch panel device according to claim 6 or 7, wherein: The second pulse waveform deformation circuit has a time constant having a size corresponding to the degree to which the pulse rise time is increased.

9. A touch panel device, characterized in that: include: a plurality of first electrode lines extending along a first direction; a plurality of second electrode lines extending along a second direction intersecting the first direction; a driving signal generating circuit for generating a driving signal input to each of the plurality of first electrode lines; an induction signal receiving circuit that receives an induction signal output from each of the plurality of second electrode lines and corresponding to a magnitude of an electrostatic capacitance of each intersection of the plurality of first electrode lines and the plurality of second electrode lines; as well as A driving signal amplifying circuit is interposed between the driving signal generating circuit and the first electrode line, and amplifies the driving signals input to the plurality of first electrode lines. inputting the drive signal amplified by the drive signal amplifying circuit to the first electrode line, The driving signal is a pulse signal, The touch panel device further includes a pulse waveform deformation circuit, the pulse waveform deformation circuit being arranged corresponding to each of the plurality of first electrode lines and deforming the pulse waveform of the pulse signal so as to increase the pulse rise time for each of the drive signals at least either before or after the drive signal amplification circuit amplifies the drive signal. The pulse waveform deformation circuit includes a second pulse waveform deformation circuit, which is interposed between the drive signal generation circuit and the drive signal amplification circuit and deforms the waveform of the drive signal before amplification by the drive signal amplification circuit.

10. The touch panel device according to claim 9, wherein: The second pulse waveform deformation circuit is a low-pass filter circuit that removes high-frequency components.

11. The touch panel device according to claim 10, wherein: The second pulse waveform deformation circuit includes: a second resistor connected in series with a second input signal wiring arranged between the drive signal generating circuit and the drive signal amplifying circuit; and A capacitor is connected in parallel with the drive signal generating circuit.

12. The touch panel device according to claim 10 or 11, wherein: The second pulse waveform deformation circuit has a time constant having a size corresponding to the degree to which the pulse rise time is increased.

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