JP2015035053A - Electrostatic capacitance type touch panel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a touch panel capable of reducing the number of wirings drawn out from a drive signal line and a detection signal line and decreasing the area of a frame area.SOLUTION: A self-modulating type touch panel 1 includes: a plurality of drive signal lines 11 to 13 formed on a transparent base material 10 with a predetermined interval; a plurality of detection signal lines 21 to 23 formed on the transparent base material 10 so as to intersect with the drive signal lines 11 to 13; and modulation circuits 30 disposed and connected at each position where the drive signal lines 11 to 13 and the detection signal lines 21 to 23 intersect. Each of the modulation circuits 30 has different characteristics.

Description

  The present invention relates to a capacitive touch panel, and more particularly, to a projected capacitive touch panel incorporating a modulation circuit.

  Smartphones and tablet PCs that can be easily operated simply by lightly touching the display screen have become widespread, and thinning, lightening, and enlargement of touch panels, which are input devices, are urgent issues.

  There are various types of touch panel detection methods, such as a resistive film method that identifies the indicated position by overlapping two resistive films, and a surface acoustic wave method that detects the indicated position by generating ultrasonic waves and surface acoustic waves on the panel surface. To do. The touch panel used for the above-described smartphone or tablet PC can be tapped with a finger on the panel, dragged, or operated to spread two fingers on the screen to enlarge the image (pinch out). It is necessary to deal with complicated and flexible operations such as a pinch-in operation that moves two fingers together. For this reason, at present, the projection type capacitive type in which an xy matrix is formed using a transparent electrode and a plurality of designated positions can be detected simultaneously has become the mainstream.

  In a projected capacitive touch panel, as described in Patent Document 1 and the like, a plurality of drive lines (drive lines) and detection lines (sense lines) that are formed and arranged so as to intersect the x direction and the y direction. ) For each number of wires, and the drawn wires need to be connected to an external controller through the outer edge of the touch panel (hereinafter referred to as a frame region).

JP 2013-3603 A

  The projected capacitive touch panel measures the combined capacitance of the capacitance formed by touching the finger from the outside with the capacitance formed by the drive line and detection line intersecting with an insulator. Thus, the contact position is detected. Therefore, the accuracy of the detection position on the touch panel depends on the number of intersections of drive lines and detection lines per unit area of the screen, that is, the number of drive lines and detection lines. Moreover, in order to realize an increase in the size of the projected capacitive touch panel, it is necessary to form a large number of drive lines and detection lines on a transparent substrate using transparent electrodes.

  Here, in order to perform the capacitance measurement for detecting the contact position, a so-called scanning method is adopted in which detection signals are sequentially supplied to the respective drive lines and the signals are sequentially detected for each detection line. Sends / receives signals from the connector to the touch panel controller via each drive line and wiring corresponding to each detection line in order to send the detection signal to the drive line and receive the capacitance measurement signal through the detection line. To do. Since these wirings cannot cross the transparent area (screen) of the touch panel, they must be routed around the frame area. By increasing the size of the display screen, the number of drive lines / detection lines is increased, and the number of wiring lines for such drive / detection is also increased, which requires a wider frame area. Although it is technically possible to reduce the area of the frame area by making the frame area multi-layered, it will go against the market demand for thinning, and the manufacturing process of the touch panel will be complicated and the cost will increase. It becomes.

  Accordingly, an object of the present invention is to provide a touch panel that can reduce the number of wirings drawn from the drive signal lines and the detection signal lines, and thereby reduce the area of the frame region.

  As a means for solving the above-described problem, a capacitive touch panel according to an embodiment of the present invention includes a plurality of first signal lines formed on a substrate at predetermined intervals, and a plurality of signal lines. A plurality of second signal lines formed on the substrate at predetermined intervals so as to intersect the first signal line, and the first signal line and the second signal line are respectively disposed at positions where the first signal line intersects. And a modulation circuit connected to each of the second signal lines. The modulation circuit has different characteristics for each position where the first and second signal lines intersect.

  A capacitive touch panel according to another embodiment of the present invention is formed on a substrate so as to intersect a plurality of first signal lines formed on the substrate and the plurality of first signal lines. A plurality of second signal lines, a modulation circuit disposed at a position where the first and second signal lines intersect, and connected to the first and second signal lines, respectively; and a plurality of first signal lines Drive wiring for sending a position detection signal to the signal line and receiving wiring for receiving the position detection signal modulated from the plurality of second signal lines through the modulation circuit. The modulation circuit has different characteristics at each position where the first and second signal lines intersect, and the number of drive wirings is smaller than the number of the plurality of first signal lines, The number is smaller than the number of the plurality of second signal lines.

  In the present invention, the modulation circuits having different characteristics are arranged at positions where the first and second signal lines intersect with each other, and are connected to the first and second signal lines, respectively. Can be reduced, and the frame area which is the peripheral part of the touch panel can be narrowed.

It is a figure which shows the circuit example of the self-modulation type touch panel which concerns on one embodiment of this invention. It is a circuit example which shows the specific example of the modulation circuit which comprises the self-capacitance type touch panel which concerns on one embodiment of this invention. (A) is a circuit configuration example of an LCR band-pass filter, and (B) is a circuit configuration example of a π-type LC band-pass filter. (C) is a circuit example of a delay line. It is a circuit diagram including the top view which shows typically the structural example of the touchscreen part of the self-modulation type touchscreen which concerns on one embodiment of this invention. (A) is a perspective view of a modulation circuit element in which a modulation circuit such as a band-pass filter is realized by a single element using thin film technology. (B) is an exploded view of FIG. It is a partially exploded perspective view for demonstrating the state in which the modulation circuit of a self-capacitance type touch panel is mounted. It is a perspective view which shows the state in which the modulation circuit of the self-capacitance type touch panel was mounted. It is an equivalent circuit diagram for confirming the operation of a self-modulation type touch panel using a bandpass filter as a modulation circuit. (A) is a figure which shows the form of the input signal input into the circuit of FIG. (B) is a figure which shows the form of the output signal of the circuit of FIG. It is an equivalent circuit diagram for confirming the operation of a self-modulation type touch panel using a delay line as a modulation circuit. (A) is a figure which shows the form of the input signal input into the circuit of FIG. (B) is a figure which shows the form of the output signal of the circuit of FIG. It is a figure which shows the mode of the waveform of the output signal when not delaying when the delay time of a delay line is selected appropriately. (A) shows the waveform of the output signal when an appropriate delay time is set, and (B) shows that the waveform of the output signal is deformed or a false signal is output because it is set to an inappropriate delay time. It is a figure which shows a mode. It is a figure which shows the frequency characteristic of the gain and phase of a system when the delay time of a delay line is selected appropriately, and when it is not so. (A) is a frequency characteristic when it is set to an appropriate delay time, and (B) is a diagram showing a state in which an abnormality is recognized in the gain and phase because it is set to an inappropriate delay time.

  Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings. It should be noted that the present invention is not limited to the following embodiments, and various modifications can be made without departing from the scope of the present invention. The description will be given in the following order.

1. 1. Circuit configuration example of self-modulating touch panel 2. Structural example of self-modulating touch panel Operation of self-modulating touch panel (1) Band pass filter method (2) Delay line method

1. FIG. 1 shows an equivalent circuit of a projected capacitive touch panel to which the present invention is applied. As will be described in detail below, the touch panel according to the present invention is referred to as a self-modulating touch panel in the following because a modulation function is developed as a whole touch panel by connecting a circuit having a function of frequency or time to the touch detection position. I will do it. For simplicity, a self-modulation type touch panel in which the detection position is 4 × 4, 3 × 3, or 4 × 3 will be described. However, the self-modulation type touch panel is not limited to these, and m × n (m, n It goes without saying that can be extended to an integer of 2 or more and generalized.

  As shown in FIG. 1, a self-modulation type touch panel 1 to which the present invention is applied includes a transparent substrate 10 and a plurality of drive signal lines 11 formed on the transparent substrate 10 approximately in parallel at a predetermined interval. To 14 and a plurality of detection signal lines 21 to 24 formed substantially in parallel with a predetermined interval on the transparent substrate 10 so as to intersect the plurality of drive signal lines 11 to 14, and the drive signal lines 11 to 11 14 and detection signal lines 21 to 24 are arranged at respective intersecting positions, and drive signal lines 11 to 14 and a plurality of modulation circuits 30 having input / outputs connected to the detection signal lines 21 to 24 are provided. The plurality of modulation circuits 30 have different frequency characteristics. In FIG. 1, the ground line of the modulation circuit 30 is omitted in order to avoid complexity and facilitate understanding, but each modulation circuit 30 is connected to the connection terminal via the ground 35. .

  The plurality of drive signal lines 11 to 14 are combined into one drive wiring 15 and connected to the connection terminal 15a. Further, the plurality of detection signal lines 21 to 24 are combined into one receiving wiring 25 and connected to the connection terminal 25a. The connection terminals 15a, 25a, and 35a formed on the transparent substrate 10 are connected to flexible printed wiring boards (FPCs) on which corresponding wiring patterns 15b, 25b, and 35b are formed. In the FPC, the FPC is connected to a controller 60 that performs detection control of the self-modulation type touch panel via the connection terminals 15c, 25c, and 35c formed on the other side of the side to which the connection terminals 15a, 25a, and 35a are connected. The The controller 60 generates a predetermined drive signal and is driven by the sense pulse signal generation circuit 61 that drives each of the drive signal lines 11 to 14 via the drive wiring 15 and the sense pulse signal generation circuit. 30 and a demodulating circuit 62 that demodulates a received signal received from the detection signal lines 21 to 24 via the receiving wiring 25. As the demodulation circuit 62, a known circuit that demodulates a signal in accordance with the signal modulated by each modulation circuit 30 can be used. As will be described later, the demodulation circuit obtains a signal in which sinusoidal signals having different frequencies are arranged in a time-division manner. Therefore, the signal is separated for each frequency component, and an initial value (default value) and Compare. More specifically, for example, the demodulation circuit 62 can A / D convert the received signal and separate the signal for each frequency component by a predetermined digital filter (CIC filter, FIR filter, etc.). The controller 60 is further connected to a microprocessor or the like and performs contact position detection control.

  The modulation circuit 30 can have various configurations. FIG. 2 shows a specific example of the modulation circuit 30.

  FIG. 2A is a circuit example of an LCR band-pass filter 30 a used as the modulation circuit 30. The band pass filter 30 a includes an input terminal 31 a connected to any one of the drive signal lines 11 to 14, an output terminal 32 a connected to any one of the detection signal lines 21 to 24, and a ground 35. The band pass filter 30a includes a resistor (R1) 33a, an inductor (L1) 36a, and a resistor (R2) 34a connected in series between the input terminal 31a and the output terminal 32a. Further, an inductor (L2) 37a and a capacitor (C2) 38a connected in parallel between the connection node of the resistor (R1) 33a and the inductor (L1) 36a and the ground 35 are connected, and the inductor (L1) 36a and the resistor ( An inductor (L3) 39a and a capacitor (C3) 40a connected in parallel between the connection node of R2) 34a and the ground 35 are connected.

  FIG. 2B illustrates an example of a Butterworth bandpass filter 30b having a configuration different from the configuration of FIG. The band pass filter 30b is a band pass filter made of LC. The band pass filter 30 b includes an input terminal 31 b connected to any one of the drive signal lines 11 to 14, an output terminal 32 b connected to any one of the detection signal lines 21 to 24, and a ground 35. The bandpass filter 30b includes an inductor (L1) 36b and a capacitor (C1) 41b connected in series between the input terminal 31b and the output terminal 32b. An inductor (L2) 37b and a capacitor (C2) 38b connected in parallel between the input terminal 31b and the ground 35 are connected, and an inductor (L3) 39b and capacitor connected in parallel between the output terminal 32b and the ground 35 are connected. (C3) 40b is connected.

  FIG. 2C shows a circuit example of the delay line 30 c used as the modulation circuit 30. The delay line 30 c includes an input terminal 31 c connected to any one of the drive signal lines 11 to 14, an output terminal 32 c connected to any one of the detection signal lines 21 to 24, and a ground 35. The delay element 42c has a delay time Td and a characteristic impedance Z0.

  In FIG. 1, the modulation circuit 30 is indicated by the same reference numeral, but the band-pass filters 30 a and 30 b and the delay line 30 c used as the modulation circuit 30 have different frequency characteristics and delay times.

  The configuration example of the modulation circuit shown in FIGS. 2A to 2C is an example. For example, a higher-order Butterworth filter may be configured by connecting the configuration of FIG. 2B in cascade. It goes without saying that other well-known different circuit configurations may be used. Further, the modulation circuit 30 is not limited to a passive element as shown in FIGS. 2A to 2C, and may be an active filter using an active element such as an FET element or a delay line. . Further, the plurality of modulation circuits 30 in FIG. 1 need not all have the same circuit configuration, and a plurality of types of filter circuits may be mixed, but in order to simplify the configuration of the demodulation circuit, the same format is used. The modulation circuit 30 is preferably used.

2. Structure Example of Self-Modulating Touch Panel FIG. 3 shows a configuration including contact electrodes that are actually formed on the transparent substrate 10.

  The self-modulating touch panel 1 to which the present invention is applied includes a square (diamond-shaped) X electrode 17 formed so as to be spaced apart from each of the drive signal lines 11 to 14 by a predetermined interval, and detection signal lines 21 to 21. Each of 24 has a square (diamond-shaped) Y electrode 27 formed so as to be separated by a predetermined interval. The X electrodes 17 and the Y electrodes 27 are alternately arranged in a checkered pattern, and are formed of the transparent electrode material on the same surface of the transparent substrate 10. The transparent base material 10 is a transparent well-known base material that is electrically insulating, and is, for example, a transparent resin such as glass or a PET resin film. As the transparent electrode material, a known material can be used. For example, a metal nanowire such as ITO, ZnO, Ag nanowire, or a material containing carbon nanotubes can be preferably used. The Y electrodes 27 that are electrically connected to the detection signal lines 21 to 24 and are adjacent to each other are electrically connected to each other by the conductive line 26. A modulation circuit 30 covered with an insulating layer 29 is disposed on the conductive line 26. The X electrodes 17 that are electrically connected to the drive signal lines 11 to 14 and are adjacent to each other are electrically connected to each other by jumper wirings 16 made of a transparent electrode material over the insulating layer 29. As the transparent electrode material constituting the jumper wiring 16, a known material can be used. From the viewpoint of utilizing existing equipment for the forming process, it is preferable to use the same transparent electrode material used for the X electrode and the Y electrode.

  The X electrode 17, the Y electrode 27, and the jumper wiring 16 can be formed on the transparent substrate 10 by a well-known method, but since an existing apparatus can be used, a coating method including screen printing and an ink jet method is used. Is preferably used.

  As the modulation circuit 30, as shown in FIG. 4, a thin film filter circuit element using a thin film forming technique may be used. The thin film filter circuit element constituting the modulation circuit 30 includes an insulating substrate 43, a first metal wiring layer 44 formed on the substrate 43, a thin film 45 formed of a dielectric, and a first metal wiring. An insulating layer 46 for insulating the second metal wiring layer 47 formed in the layer 44; an overcoat layer 48 for protecting the second metal wiring layer 47; and a through hole such as the overcoat layer 48 An electrode 49 for connecting to a predetermined position of the first and second metal wiring layers 44 and 47 via the via and connecting to an external circuit, a further overcoat layer 50, and a marking layer 51 for identification It is formed by stacking.

  The modulation circuit 30 is not limited to such a thin film filter circuit, and may be a device laminated in multiple layers using LTCC (Low temperature Co-fired Ceramic) technology, such as a filter circuit or a delay line circuit. May be formed by arranging individual chip parts.

  More specifically, as shown in FIGS. 5 and 6, a wiring pattern 55 is formed on the X electrode 17, the Y electrode 27, and the ground 35 formed on the transparent substrate 10 via an insulator (not shown). Thus, the bandpass filter 30a shown in FIG. As shown in FIG. 5, each component of the resistor, capacitor, and inductor constituting the band pass filter 30a may be constituted by individual chip components, and the thin film filter circuit as described above or a single element by the LTCC technology is mounted. May be.

  An input terminal 31 a of the band pass filter 30 a is connected to the X electrode 17, and an output terminal 32 a is connected to the Y electrode 27. Each component constituting the band pass filter 30a (series resistors (R1, R2) 33a, 34a, series inductor (L1) 36a, parallel inductors (L2, L3) 37a, 39a, parallel capacitors (C2, C3) 38a, 40a) Is disposed on a conductive line 26 that electrically connects adjacent Y electrodes 27 and 27, and is mounted on a wiring pattern 55 that is formed so as to have a predetermined electrical connection. The configuration of the modulation circuit 30 is not limited to the band-pass filter 30a, but may be a band-pass filter 30b or the like having a different configuration, a delay line 30c, or the like, or another known modulation circuit. An insulating layer 29 is formed on each mounted component for electrical insulation. For the insulating layer 29, a known insulating material may be used, and a transparent ultraviolet curable or thermosetting resin paint or the like that is transparent at the time of curing may be used. A jumper wiring 16 is formed over the insulating layer 29, and the adjacent X electrodes 17 and 17 are electrically connected to each other. As described above, the jumper wiring 16 can be formed of the same material as the transparent electrode such as the X electrode 17 and the Y electrode 27 by using, for example, a transparent electrode material including Ag nanowires using an inkjet technique.

  As shown in FIG. 6, after the jumper wiring 16 is formed, a band-pass filter 30a, which is a modulation circuit covered with an insulating layer 29, is arranged and formed at each connection position where the X electrode and the Y electrode intersect. .

3. Operation of Self-Modulating Touch Panel In the following, as a specific example, self-modulation to which the present invention is applied when band-pass filters with different center frequencies are arranged and delay lines with different delay times are arranged. Each operation of the type touch panel will be described.

(1) Bandpass Filter Method FIG. 7 shows an equivalent circuit when a π-type LC bandpass filter is used as the modulation circuit 30. FIG. 7 shows a 3 × 3 self-modulation type touch panel, that is, self-modulation in which nine band pass filters BPF11 to BPF33 are arranged and connected at positions where the drive signal lines 11 to 13 and the detection signal lines 21 to 23 intersect. It is an equivalent circuit of a type touch panel.

  A drive signal is supplied from the signal source connected to the input port 70 to the band pass filters BPF11 to BPF33 via the drive wiring 15 and the drive signal lines 11 to 13. Then, the signal supplied from the signal source is output as a detection signal from the detection signal lines 21 to 23 via the reception wiring 25 (OUTPUT 71). Table 1 shows constants of the bandpass filters BPF11 to BPF33.

  As shown in FIG. 8A, the signal source connected to the input port 70 includes a signal in which sinusoidal signals having different frequencies are arranged in time series. The frequency of each arranged sine wave signal is set to match the center frequency of the nine band-pass filters BPF11 to BPF33. That is, the frequency of the first sine wave signal I_11 is 100 kHz, which is the center frequency of the bandpass filter BPF11. The frequency of the next sine wave signal I_22 is 500 kHz, which is the center frequency of the bandpass filter BPF22. The frequency of the third sine wave signal I_33 is 1.5 MHz, which is the center frequency of the bandpass filter BPF33. Similarly, the frequencies of the sine wave signals I_23, I_12, I_31, I_32, I_21, and I_13 are set equal to the center frequencies of the bandpass filters BPF23, BPF12, BPF31, BPF32, BPF21, and BPF13, respectively. In FIG. 8A, the duration of each frequency is 0.2 ms and the duty cycle is 50%, but it goes without saying that these can be arbitrarily set.

  When the signal shown in FIG. 8A is input to the input port 70, it passes through all nine band-pass filters BPF11 to BPF33 via the drive signal lines 11 to 13. Then, signals equal to the center frequencies of the bandpass filters BPF11 to BPF33 pass through the bandpass filters BPF11 to BPF33, respectively. Therefore, as shown in FIG. 8B, the OUTPUT 71 outputs a signal having the same frequency array as the array composed of the frequencies of the input signal. That is, the output signal O_11 output first is the same frequency 100 kHz as the sine wave signal I_11, and the output signal O_22 output next is the same frequency 500 kHz as the sine wave signal I_22 and is output third. The output signal O_33 has the same frequency of 1.5 MHz as the sine wave signal I_33. Similarly, the output signals O_23, O_12, O_31, O_32, O_21, and O_13 are output at times corresponding to the sine wave signals I_23, I_12, I_31, I_32, I_21, and I_13, respectively. The frequency of I_23, I_12, I_31, I_32, I_21, I_13 is equal to 800 kHz, 400 kHz, 900 kHz, 1.2 MHz, 200 kHz, 700 kHz.

  When a finger or the like touches the touch panel, capacitance is added to the contact position, so that the pass characteristic of the bandpass filter near the contact position changes, and the waveform of the output signal to be output changes. The waveform before the capacitance is added is stored as a digital value after A / D conversion as an initial value, and the contact position can be detected by detecting the presence or absence of a waveform change in the output signal of any frequency. . As shown in FIG. 8B, the amplitudes of the respective output signals are not equal due to the impedance 56 of the transparent electrode, the wiring, etc. indicated by the resistance in FIG.

  The frequency arrangement of the sine wave signals input to the touch panel is not limited to the order shown in FIG. 8A. However, when a signal having a frequency equal to the frequency that is the difference between the frequencies is used as the input signal, Since it becomes difficult to obtain a stable output signal due to interference with the signal, it is preferable not to include a signal having a frequency that is a difference between the frequencies in the input signal. In order to prevent interference in the output signal, it is more preferable to select the frequency of each input signal at random.

  In this way, the contact position can be detected by driving the drive signal line with a sine wave signal equal to the center frequency of each bandpass filter and acquiring the change in the output signal due to the presence or absence of contact. The input sine wave signal is arranged in time series for each frequency and supplied to the drive signal line, and the output signal to be output is also arranged in time series for each frequency corresponding to the input sine wave signal. Since it is sent to the line, if there is only one wiring for driving and receiving, the contact position can be detected. In addition, since the input sine wave signals are arranged in time series, each frequency component can be easily separated, so that the configuration of the demodulation circuit can be simplified.

  Furthermore, the number of wires passing through the frame region can be only one each of the ground wire, the drive wire, and the receiving wire, and the area of the frame region can be reduced.

(2) Delay Line System FIG. 9 shows an equivalent circuit when delay lines having different delay times are arranged as the modulation circuit 30. FIG. 9 shows a 4 × 3 self-modulating touch panel, that is, a case where a total of 12 delay lines DLY11 to DLY34 are arranged and connected at positions where the drive signal lines 11 to 14 and the detection signal lines 21 to 23 cross each other. It is an equivalent circuit.

A signal source that outputs a square pulse wave input signal VIN as shown in FIG. 10A is connected to the input port 72. In this case, a square pulse wave having a pulse width of 5 ns was used, but it is needless to say that the specifications of the input signal such as the pulse width can be arbitrarily set according to the detection accuracy of the signal. The input signal VIN is not limited to a square pulse wave, and a triangular wave, a sine wave, or any other signal having an arbitrary waveform can be used.
Table 2 shows characteristic values of the delay lines DLY11 to DLY34.

  When a square pulse signal as shown in FIG. 10A is input as the input signal VIN from the input port 72, the input signal VIN is distributed to the drive signal lines 11 to 14 via the drive wiring 15, and each delay line. DLY11 to DLY34 are reached. The signals reaching the delay lines DLY11 to DLY34 are output to the detection signal lines 21 to 23 with a delay corresponding to the delay time of each delay line. Since the delay times of the delay lines DLY11 to DLY34 are all different, the pulse signal output from the OUTPUT 73 via the reception wiring 25 is output to a position on the time axis corresponding to the delay time of the delay lines DLY11 to DLY34. . Therefore, the sequence of output signals output from the OUTPUT 73 is as shown in FIG. That is, the first output signal DO_11 is output with a delay of 320 ns of the delay line DLY11, and the next output signal DO_12 is output with a delay of 330 ns of the delay line DLY12. Similarly, output signals DO_13, DO_14, DO_21, DO_22, DO_23, DO_24, DO_31, DO_32, DO_33, DO_34 are respectively sent to delay lines DLY13, DLY14, DLY21, DLY22, DLY23, DLY24, DLY31, DLY32, DLY33, DLY34. The corresponding delay times 340 ns, 370 ns, 410 ns, 430 ns, 440 ns, 450 ns, 520 ns, 540 ns, 550 ns, and 560 ns are output with a delay.

  Here, when the touch panel is touched with a finger or the like, the characteristics of the delay line in the vicinity of the contact position change, and the delay time of the delay line increases. Therefore, the initial output signal position is stored as an initial phase as a digital value after A / D conversion, and the contact position can be specified by measuring the phase difference for each output signal pattern.

  Here, although it is necessary to make the delay times of all the delay lines different, the same row (for example, DLY11, DLY12, DLY13, DLY14, etc.) is accurate because the pulse signal passes through the same wiring and causes interference due to reflection. In order to detect the phase, it is necessary to reduce such mutual interference as much as possible.

  FIG. 11A and FIG. 11B show measurement data comparing the cases where the signals that have passed through the delay line interfere with each other. FIG. 11A shows measured values of the output signal under the same conditions as FIG. FIG. 11B shows measured values of the output signal when the delay times of the delay lines DLY11, DLY12, DLY13, and DLY14 in the first row are 10 ns, 20 ns, 30 ns, and 40 ns, respectively (on the time axis, The waveforms of DLY11 to DLY14 are not shown.) The delay times of the delay lines in the second and third rows are the same as those in FIG. 11A, but underlines the waveforms of the output signals DO_22 ′, DO_23 ′, and DO_24 ′ corresponding to DLY22, DLY23, and DLY24. Abnormalities (deformations) such as shoots and waveform rounding are observed. Also, abnormal waveforms are observed in the waveforms of the output signals DO_21 ', DO_22', DO_23 ', and DO_24' corresponding to the delay lines DLY31, DLY32, DLY33, and DLY34 in the third row. Further, a false signal that is considered to be an influence of reflection is observed behind each of the delay lines in the second and third rows.

  FIGS. 12A and 12B are graphs plotting the frequency characteristics of the phases corresponding to FIGS. 11A and 11B, respectively. FIG. 12A shows the frequency characteristics in a normal state without interference, and FIG. 12B shows the frequency characteristics in the case of interference. FIG. 12A shows that the gain changes with periodicity in a frequency region of 2 MHz or higher, and FIG. 12B shows that the gain changes irregularly.

  In order to reduce such signal interference, each delay time of the delay line is preferably set at random. For example, it is more preferable to set the delay time for each row with a PN (pseudorandom noise) code pattern. In addition, it goes without saying that a known random value setting method can be used.

  In this way, the contact position can be detected by detecting the output signal corresponding to the delay time of each delay line and measuring the phase change. The input signal is only a single pulse signal, and the output signal to be output is also arranged in time series according to the delay time of the delay line. Detection can be performed. Further, since the output signals are arranged in time series, each phase can be easily detected, and the configuration of the demodulation circuit can be simplified.

  The number of wirings that pass through the frame region is only one each of the ground line, the drive wiring, and the reception wiring, and the area of the frame region can be reduced.

  By arranging and connecting frequency parameter elements having different characteristics such as band pass filters and delay lines arranged at positions where the drive signal line and the detection signal line intersect as described above, the drive wiring and the reception wiring are arranged. It is possible to configure a touch panel that can specify the contact position only by drawing the frame area one by one. If the screen of the touch panel is divided appropriately (two divisions, four divisions, etc.) and the above-described self-modulation method is adopted for each divided screen, the frame area can be obtained by drawing one drive wiring and one reception wiring for each divided screen. It is possible to realize a further large-screen touch panel without increasing the value.

DESCRIPTION OF SYMBOLS 1 Self-modulation type touch panel, 10 Transparent base material, 11-14 Drive signal line, 15 Drive wiring, 16 Jumper wiring layer, 17 X electrode, 21-24 Detection signal line, 25 Reception wiring, 26 Conductive line, 27 Y electrode, 30 modulation circuit, 31 input terminal, 32 output terminal, 33, 34 resistance, 35 ground, 36, 37, 39 inductor, 40, 41 capacitor, 42c delay element, 43 substrate, 44 first metal wiring layer, 45 thin film layer , 46 Insulating layer, 47 Second metal wiring layer, 48 Overcoat layer, 49 Terminal, 50 Overcoat layer, 51 Marking layer, 60 Controller

Claims (7)

A plurality of first signal lines formed at predetermined intervals on the substrate;
A plurality of second signal lines formed on the substrate at predetermined intervals so as to intersect the plurality of first signal lines;
A modulation circuit disposed at a position where the first and second signal lines intersect and connected to the first and second signal lines, respectively.
The capacitive touch panel, wherein the modulation circuit has different characteristics for each position where the first and second signal lines intersect. The first signal line is electrically insulated from the second signal line by an insulator at a position intersecting the second signal line,
The capacitive touch panel according to claim 1, wherein the modulation circuit is covered with the insulator. The modulation circuit includes a band-pass filter,
3. The capacitive touch panel according to claim 1, wherein the band-pass filter has a different center frequency for each position where the first and second signal lines intersect. The modulation circuit includes a delay line,
3. The capacitive touch panel according to claim 1, wherein the delay line has a different delay time for each position where the first and second signal lines intersect. A demodulation circuit for demodulating a signal connected to the second signal line and received by the signal applied to the first signal line via the modulation circuit;
The capacitive touch panel according to claim 1, wherein the demodulation circuit performs position detection by performing demodulation corresponding to the modulation circuit. A plurality of first signal lines formed on the substrate;
A plurality of second signal lines formed on the substrate so as to intersect the plurality of first signal lines;
A modulation circuit disposed at a position where the first and second signal lines cross each other, and connected to the first and second signal lines, respectively;
Drive wiring for sending position detection signals to the plurality of first signal lines;
Receiving wiring for receiving a position detection signal modulated through the modulation circuit from the plurality of second signal lines,
The modulation circuit has different characteristics for each position where the first and second signal lines intersect,
The number of the drive wirings is smaller than the number of the plurality of first signal lines,
The capacitive touch panel characterized in that the number of the reception wirings is smaller than the number of the plurality of second signal lines.   The capacitive touch panel according to claim 6, wherein the number of the drive wirings and the number of the reception wirings is one each.