JP2016173685A - Static capacitance type touch panel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a static capacitance type touch panel that detects the input operation position of an ordinary input operation quickly with high accuracy, and when a multi-touch operation is detected, switches to an input operation of mutual capacitance type which is free of the problem of ghost occurrence before an input operation medium touches an input operation surface.SOLUTION: For an ordinary input operation, a first detection circuit is actuated, and the distance d between a direct detection electrode and an input operation medium is found from a reception level Vi of a first AC detection signal appearing at a detection electrode, to detect an input operation position. When a multi-touch operation is detected by the first detection circuit, a second detection circuit of mutual capacitance type is actuated to detect the input operation position, so that each input operation position of the multi-touch operation can be detected without the problem of ghost occurrence.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a capacitive touch panel that detects an input operation position from an arrangement position of a detection electrode on an input operation surface, in which the capacitance with the input operation body changes as the input operation body approaches. Relates to a capacitive touch panel that accurately detects each input operation position even when there is a so-called multi-touch operation in which a plurality of positions on the input operation surface are input simultaneously.

  As the detection method of the input operation position of the capacitive touch panel, for example, as shown in JP 2013-534343 A (Patent Document 1), a detection electrode in which stray capacitance increases as the input operation body approaches The self-capacitance method (one-wire method) that detects the input operation position from the center of gravity for comparing the amount of change in stray capacitance for a plurality of detection electrodes, and Japanese Patent Publication No. 2012-502397 (Patent Document 2) As described above, an AC detection signal of a predetermined voltage level is applied to the drive electrode, and the input operation position is detected from the intersection position of the detection electrode where the reception level of the AC detection signal is lowered when the drive electrode approaches the input operation body. It is divided into the mutual capacity method (two-wire type).

  In the self-capacitance method, only the plurality of detection electrodes insulated from each other are wired in the first direction and the second direction along the input operation surface, and the drive electrode is not wired, so that the structure is simplified. If the number of detection electrode wirings is scanned, the input operation positions in the first direction and the second direction can be detected, so that there is an advantage in that the scan time is short and the power consumption is small. In a multi-touch operation in which it is difficult to narrow down the position to one place and two or more positions on the input operation surface are input simultaneously, in addition to the actual input operation position, different positions in the first direction and the second direction are set. There is a problem of “ghosting” that is erroneously detected as the input operation position.

  On the other hand, in the mutual capacitance method, the plurality of first detection electrodes wired in the first direction and the second detection electrodes wired in the second direction are insulated from each other and wired along the input operation surface of the insulating panel. Scanning with one drive electrode for applying an AC detection signal and the other electrode for detecting the reception level of the AC detection signal for all the intersection positions of the drive electrode and the detection electrode, and the detection electrode and drive with a lowered reception level Input operation positions in the first direction and the second direction are detected from the intersection positions of the electrodes. Therefore, even if there is a multi-touch operation, each input operation position is accurately detected, and there is no problem of ghosting. However, since all the intersection positions of the first detection electrode and the second detection electrode are scanned, the scan time Becomes longer, the response speed of the input operation decreases, and the power consumption increases.

  Therefore, a capacitance sensor that can switch between the self-capacitance method and the mutual capacitance method depending on the purpose of detection is also known (Japanese Patent Laid-Open No. 2015-31552 (Patent Document 3)). The operation of this conventional capacitance sensor 100 will be described below with reference to FIGS. 6 and 7, 101 is a transmission circuit for transmitting an AC detection signal, 102 is a voltmeter, a reception circuit for detecting the reception level of the AC detection signal, and 103 is a drive arranged on the input operation surface. A transmission electrode serving as both an electrode and a detection electrode, 104 is a reception electrode serving as a detection electrode arranged in the vicinity of the transmission electrode 103 on the input operation surface, and 107 is a forward direction from the transmission circuit 101 to the transmission electrode 103. A diode 108 is connected to a grounding capacitor for detecting the potential of the receiving electrode 104 by a mutual capacitance method.

  When the capacitance sensor 100 is operated by the self-capacitance method to detect the detected object (input operating body) 110, a switch 105 between the transmission electrode 103 and the reception circuit 102 is provided as shown in FIG. ON, the switch 106 between the receiving electrode 104 and the receiving circuit 102 is turned OFF. When an AC detection signal is transmitted from the transmission circuit 101 to the transmission electrode 103 and the detected object 110 approaches the transmission electrode 103, the self-capacitance (capacitance) 120 therebetween is charged by the AC detection signal. The potential of the transmission electrode 103 gradually rises as this capacitance is charged, and the switch 105 is turned on and the reception circuit 102 connected to the transmission electrode 103 has the potential of the rising transmission electrode 103 kept constant. Detect the elapsed time to reach.

  Since the capacitance 120 between the transmission electrode 103 and the detected object 110 is inversely proportional to the distance between them, the capacitance increases as the detected object 110 approaches the transmission electrode 103, and the capacitance 120 is charged by the AC detection signal. As a result, the rising speed of the potential of the transmitting electrode 103 is also slowed, and the elapsed time detected by the receiving circuit 102 is lengthened. Therefore, the capacitance sensor 100 detects that the detection object 110 has approached the transmission electrode 103 because the elapsed time detected by the reception circuit 102 becomes long.

  Further, when detecting the object to be detected (input operation body) 110 by operating the capacitance sensor 100 in the mutual capacitance method, a switch between the transmission electrode 103 and the reception circuit 102 as shown in FIG. 105 is turned off, and the switch 106 between the receiving electrode 104 and the receiving circuit 102 is turned on. When an AC detection signal is transmitted from the transmission circuit 101 to the transmission electrode 103, a combined capacitance composed of the mutual capacitance (capacitance) 130 and the ground capacitance 108 between the transmission electrode 103 and the reception electrode 104 connected in series is charged. The potential on the high voltage side of the receiving electrode 104 or the grounding capacitor 108 gradually rises due to charging, and the receiving circuit 102 connected to the high voltage side of the grounding capacitor 108 detects the elapsed time until this rising potential reaches a certain potential. .

  When the object 110 to be detected does not exist between the transmission electrode 103 and the reception electrode 104, the combined capacitance of the mutual capacitance (capacitance) 130 and the ground capacitance 108 to which the current due to the AC detection signal is connected in series is set. When the object to be detected 110 approaches between the electrodes 103 and 104, a part of the current flows from the transmission electrode 103 to the object to be detected 110, and the mutual capacitance (capacitance) 130 decreases. The combined capacity is also reduced, the charging speed is increased, and the elapsed time detected by the receiving circuit 102 is shortened. Accordingly, since the elapsed time detected by the reception circuit 102 is shortened, the capacitance sensor 100 detects that the detection object 110 has approached the transmission electrode 103 and the reception electrode 104, and the transmission electrode 103 and the reception electrode. The position of the detected object 110 is detected from the arrangement position 104.

  This self-capacitance method of the capacitance sensor 100 can detect the approached state before the detection object 110 reaches the transmission electrode 103 on the input operation surface, but the elapsed time detected by the reception circuit 102 becomes longer. Since the approach of the detection object 110 is detected, the detection time is long. On the other hand, the mutual capacitance method cannot detect the detected object 110 until the detected object 110 approaches between the transmitting electrode 103 and the receiving electrode 104, but the elapsed time detected by the receiving circuit 102 is shortened. Since the approach of 110 is detected, the detection object 110 that has a short detection time and moves at high speed can be detected. Therefore, the capacitance sensor 100 switches between the self-capacitance method and the mutual capacitance method, and normally detects the approach of the detected object 110 by the self-capacitance method, and after the approach of the detected object 110 is detected. The movement of the detection object that moves at high speed is detected by switching to the operation of the mutual capacitance method.

Special table 2013-534343 gazette Special table 2012-5029797 gazette JP2015-31552A

  When the two-dimensional two-direction input operation position is detected by the self-capacitance method, the above-mentioned “ghost generation” problem occurs. When a large number of auxiliary detection electrodes are wired in different directions and two or more input operation positions are detected, the input operation position actually multi-touched is determined from the change in capacitance of each auxiliary detection electrode. Yes. However, in this method, in addition to the detection electrodes in two directions, a plurality of auxiliary detection electrodes in different directions must be wired so that all the detection electrodes are insulated from each other. It is not practical because it is complicated.

  If the input operation position is detected by the mutual capacitance method, there is no problem of ghost generation, and each input operation position by the multi-touch operation can be detected. Therefore, Patent Document 3 switches between the self-capacitance method and the mutual capacitance method according to the detection application. In combination with the described invention, a capacitive touch panel that switches from the self-capacitance method to the mutual capacitance method only when a multi-touch operation is detected has been studied.

  However, as disclosed in Patent Document 1 and Patent Document 3, when the input operation position of the input operation body is detected by the conventional self-capacitance method, between the input operation body and the detection electrode to which the AC detection signal is applied. Since the distance between the detection electrode and the input operation body is obtained from the elapsed time until reaching a predetermined charging potential that changes according to the amount of change in the capacitance of the input, the distance between the input operation body and the detection operation electrode Although it is inversely proportional to the capacitance between the body and the detection electrode, there is no linearity with the elapsed time that is actually detected, and the distance between the detection electrode and the input operation body cannot be detected with high accuracy from the elapsed time.

  In particular, when a two-dimensional input operation position in two directions is detected as described in Patent Document 1, the input operation object is determined from the center of gravity of the amount of change in capacitance for each detection electrode wired in two directions. The input operation position in two directions is detected, and since there is no linearity and distance from the input operation body in the elapsed time representing the amount of change in capacitance for each detection electrode, the input operation position obtained from its center of gravity The accuracy of. Therefore, even if the self-capacitance method is switched to the mutual capacitance method only when a multi-touch operation is detected, the self-capacitance method cannot be adopted for detecting a normal input operation position that does not detect the multi-touch operation.

  Furthermore, since the self-capacitance type capacitive touch panel has poor detection accuracy of the input operation position as described above, it is difficult to detect the multi-touch operation itself, and at least two or more input operation bodies are provided on the input operation surface. If it is not close enough to touch, the two or more independent input operation positions cannot be detected. Even if the self-capacitance method is switched to the mutual capacitance method only when a multi-touch operation is detected, a ghost is generated. Switching to a mutual capacity system that does not cause a problem will be delayed.

  On the other hand, according to the mutual capacitance method disclosed in Patent Document 2, there is no problem of ghost generation, and the input operation position can be detected with high accuracy. However, when the two-dimensional two-direction input operation position is detected. Needs to perform scanning to detect a change in capacitance at all intersection positions of a plurality of drive electrodes wired in the first direction and a plurality of detection electrodes wired in the second direction. The input operation position cannot be detected at high speed. This problem becomes more conspicuous when the input operation surface of the touch panel is enlarged and a large number of drive electrodes and detection electrodes need to be wired. Therefore, the mutual capacitance method is always adopted regardless of whether or not a multi-touch operation is detected. There is also a problem.

  The present invention has been made in consideration of such conventional problems, and provides a capacitive touch panel that detects an input operation position of a normal input operation that is not a multi-touch operation at high speed and with high accuracy. For the purpose.

  It is another object of the present invention to provide a capacitive touch panel that switches to a mutual capacitance method that does not cause a ghost problem before the input operation body touches the input operation surface when a multi-touch operation is detected.

In order to achieve the above-described object, the capacitive touch panel according to claim 1 includes a plurality of first detection electrodes wired in a first direction along the input operation surface of the insulating substrate, and a first along the input operation surface. A plurality of second detection electrodes wired in a second direction crossing one direction, and a first AC detection signal in which a relative potential between the first detection electrode, each detection electrode of the second detection electrode, and the input operation body varies. First transmission means for transmitting, and first signal detection means for detecting the reception level of the first AC detection signal appearing on each detection electrode via the capacitance between each detection electrode and the input operation body, Based on the reception level of the first AC detection signal detected for each detection electrode, the distance between the detection electrode and the input operation body is obtained, and the distance between each detection electrode and the input operation body is compared. A first detection circuit for detecting an input operation position, and a plurality of first detection electrodes in order A second transmission means for transmitting a flow detection signal, and a plurality of second intersecting with the first detection electrode for transmitting the second AC detection signal via a capacitance between the first detection electrode and the second detection electrode. And a second signal detecting means for detecting a reception level of the second AC detection signal appearing on the detection electrode, the first detection electrode on which the input operation body approaches and the reception level changes and the second detection electrode on the insulating substrate A second detection circuit that detects the input operation position of the input operation body on the input operation surface from the intersection position, and a multi-touch operation is determined when the first detection circuit detects an input operation position by two or more input operation bodies And a switching control circuit that switches to the operation of either the first detection circuit or the second detection circuit according to the determination result of the determination means,
When the determination means does not determine multi-touch operation, the first detection circuit is operated to detect the input operation position of the input operation body on the input operation surface, and when the determination means determines multi-touch operation, The second detection circuit is operated to detect the input operation positions of two or more input operation bodies on the input operation surface.

  The capacitance between the detection electrode and the input operation body is Cm, the distance between the detection electrode and the input operation body is d, the output level of the first AC detection signal is Vs, and k is a constant. The reception level Vi that appears is expressed by Vi = Vs / (d · k), and is inversely proportional to the distance d between the detection electrode and the input operating body. Accordingly, the first detection circuit performs the input operation with the first detection electrode in the direction orthogonal to the first direction from the reception level Vi of the first AC detection signal detected by the first detection electrode wired along the first direction. The distance between the bodies is between the second detection electrode and the input operation body in the direction orthogonal to the second direction from the reception level Vi of the first AC detection signal detected by the second detection electrode wired along the second direction. Are obtained, and a two-dimensional input operation position along the input operation surface can be detected.

  For a normal input operation that is not determined to be a multi-touch operation by the determination means, the first detection circuit operates to detect the input operation position. Since the reciprocal of the reception level Vi detected for each detection electrode by the first detection circuit is linear with the distance d between the detection electrode and the input operation body, the input operation position of the input operation body is accurately detected from the reception level Vi. It is possible to detect a two-dimensional input operation position on the input operation surface only by detecting the reception level Vi for the total number of first detection electrodes and second detection electrodes.

  The second detection circuit includes a first detection electrode that applies the second AC detection signal and a second detection electrode that detects the reception level of the second AC detection signal. (2) The input operation position is detected as a two-dimensional input operation position on the input operation surface from the wiring positions of the first detection electrode and the second detection electrode that intersect at the intersection position where the reception level of the AC detection signal is lowered. According to the second detection circuit, since the reception level of the second AC detection signal due to the approach of the input operation body is detected at all the intersection positions, each input operation position can be determined without causing a ghost even if there is a multi-touch operation. It can be detected accurately.

  Since the first detection circuit and the second detection circuit share the plurality of first detection electrodes and the plurality of second detection electrodes, the input operation position can be detected by different detection methods without significantly changing the structure.

  In the capacitive touch panel according to claim 2, the determination unit detects an input operation position by two or more input operation bodies before the first detection circuit detects an input operation position of the input operation body on the input operation surface. In this case, it is determined that the operation is a multi-touch operation.

  According to the first detection circuit, since the input operation position can be detected with high accuracy, the determination means can determine that the input operation surface is a multi-touch operation even if a plurality of input operation bodies are separated from the input operation surface. Before the touch operation, the second detection circuit can be activated to detect each input operation position of the multi-touch operation at high speed.

  In the capacitive touch panel according to claim 3, when the switching control circuit determines that the multi-touch operation is determined by the determination unit, the operation is switched from the first detection circuit to the second detection circuit, and the second detection circuit performs the input operation. When the input operation position of any input operation body on the surface is not detected, the operation is switched from the second detection circuit to the first detection circuit.

  In the multi-touch operation, the second detection circuit operates to detect the input operation position, and when the multi-touch operation input operation ends, the first detection circuit operates. Therefore, the first detection circuit operates in the standby state of the input operation. To do.

The capacitive touch panel according to claim 4, wherein the first detection circuit further includes a primary DC power supply circuit that outputs a DC voltage between the low-voltage reference power supply line and the high-voltage reference power supply line, one of which is grounded or at a constant potential. A secondary DC power supply circuit that outputs a DC voltage from between the low-voltage vibration power supply line and the high-voltage vibration power supply line; and a high impedance for the first AC detection signal that is connected between the low-voltage reference power supply line and the low-voltage vibration power supply line. A first inductor that is connected between the high-voltage reference power supply line and the high-voltage vibration power supply line and that has a high impedance with respect to the first AC detection signal; And a first capacitor and a second capacitor connected respectively between the high-voltage reference power line and the low-voltage reference power line,
While operating the first detection circuit, the operation of the second transmission means is stopped, and the first AC detection signal is output from the first transmission means to the primary DC power supply circuit via the first capacitor and the second capacitor. In addition, each detection electrode is connected to either the low-voltage vibration power supply line or the high-voltage vibration power supply line of the secondary DC power supply circuit and vibrated at the frequency of the first AC detection signal.
While the second detection circuit is operated, the second AC detection signal is sequentially output from the second transmission means to the plurality of first detection electrodes, and the output impedance viewed from the first capacitor and the second capacitor of the first transmission means is determined. The output of the 1st alternating current detection signal of a 1st transmission means is stopped as low impedance, It is characterized by the above-mentioned.

  While operating the first detection circuit, the primary DC power supply circuit operates with the secondary DC power supply circuit because one of the low-voltage reference power supply line and the high-voltage reference power supply line is connected to the ground or a constant potential and has a constant potential. When the first AC detection signal is output from the first transmitting means to the primary DC power supply circuit via the first capacitor and the second capacitor, the secondary DC power supply circuit relatively fluctuates at the frequency f of the first AC detection signal. . Since each detection electrode is connected to either the low-voltage vibration power supply line or the high-voltage vibration power supply line of the secondary DC power supply circuit, the potential relative to the constant potential input operation body at the frequency f of the first AC detection signal is relatively high. Fluctuate.

  While the second detection circuit is operated, a low-pass filter is formed between the primary DC power supply circuit and the secondary DC power supply circuit from the first inductor and the first capacitor or the second inductor and the second capacitor. The high frequency noise of the power supply circuit does not flow to each circuit connected to the secondary DC power supply circuit, and the high frequency noise generated in each circuit connected to the secondary DC power supply circuit does not flow to the primary DC power supply circuit side.

  According to a fifth aspect of the present invention, there is provided a capacitive touch panel input operation position detection method in a second direction intersecting the first direction with a plurality of first detection electrodes wired in the first direction along the input operation surface of the insulating substrate. A first AC detection signal whose relative potential with the input operation body varies is transmitted to each detection electrode of the plurality of second detection electrodes to be wired, and through the capacitance between each detection electrode and the input operation body, Detecting the reception level of the first AC detection signal appearing on each detection electrode, and determining the distance between the detection electrode and the input operating body based on the reception level of the first AC detection signal detected for each detection electrode; The input operation position of the input operation body is detected by comparing the distance between each detection electrode and the input operation body, and the input operation position by a single input operation body is detected until the detected input operation position reaches the input operation surface. Input, the input of the input operation body on the input operation surface When the operation position is detected and the input operation position by two or more input operation bodies is detected before the detected input operation position reaches the input operation surface, the transmission of the first AC detection signal is stopped and a plurality of input operation positions are stopped. A second AC detection signal is sequentially transmitted to the first detection electrode, and a plurality of crossing the first detection electrode that transmits the second AC detection signal via the capacitance between the first detection electrode and the second detection electrode. The reception level of the second AC detection signal appearing on each second detection electrode is detected, and the input operation is performed from the crossing position on the insulating substrate of the first detection electrode and the second detection electrode where the input operation body approaches and the reception level changes. The input operation position of the input operation body on the surface is detected.

  The capacitance between the detection electrode and the input operation body is Cm, the distance between the detection electrode and the input operation body is d, the output level of the first AC detection signal is Vs, and k is a constant. The reception level Vi that appears is expressed by Vi = Vs / (d · k), and is inversely proportional to the distance d between the detection electrode and the input operating body. Therefore, from the reception level Vi of the first AC detection signal detected by the first detection electrode wired along the first direction, the distance between the first detection electrode and the input operation body in the direction orthogonal to the first direction is The distance between the second detection electrode and the input operation body in the direction orthogonal to the second direction is obtained from the reception level Vi of the first AC detection signal detected by the second detection electrode wired along the second direction. The two-dimensional input operation position along the input operation surface can be detected.

  If the input operation position is a single input operation body until the detected input operation position reaches the input operation surface, the input operation position is detected from the reception level Vi of the first AC detection signal by the same method. Since the reciprocal of the reception level Vi detected for each detection electrode is linear with the distance d between the detection electrode and the input operation body, the input operation position of the input operation body can be accurately detected from the reception level Vi, and the first detection A two-dimensional input operation position on the input operation surface can be detected by simply detecting the reception level Vi for the total number of electrodes and the second detection electrodes.

  When the input operation position by two or more input operation bodies is detected before the detected input operation position reaches the input operation surface, the first detection electrode and the second detection electrode are changed at each intersection position on the insulating substrate. (2) Since the reception level of the AC detection signal is detected and the input operation position of the input operation body on the input operation surface is detected from the crossing position where the reception level changes, there is no problem of ghosting even if there is a multi-touch operation. Each input operation position can be accurately detected. Even if multiple input operation bodies are separated from the input operation surface, it can be determined as a multi-touch operation, and before touching the input operation surface, switching to a different input operation position detection method can be performed at high speed. Each input operation position can be detected.

  According to invention of Claim 1, the input operation position of normal input operation which is not multi-touch operation can be detected at high speed and with high precision.

  When a multi-touch operation is detected, the second detection circuit is operated to detect the input operation position using a mutual capacitance method that does not cause ghosting. Can be detected.

  In addition, since the common first detection electrode and second detection electrode are used for the detection method of different input operation positions by the first detection circuit and the second detection circuit, the first detection circuit and the first detection circuit can be used without significantly changing the structure. It can be set as the electrostatic capacitance type touch panel which switches operation | movement of a 2nd detection circuit.

  According to the second aspect of the present invention, it is possible to detect the multi-touch operation before the input operation body touches the input operation surface, and to switch to the mutual capacitance method that does not cause a ghost problem.

  According to the invention of claim 3, in the multi-touch operation, since the second detection circuit operates to detect the input operation position, each input operation position is detected without the problem of ghosting. In the state of waiting for the input operation, the first detection circuit operates, so that the input operation position of the hover operation where the input operation body is separated from the input operation surface can be detected.

  According to the invention of claim 4, when the input operation position is detected by operating the first detection circuit, the first transmission means is not provided on the input operation body side, and the first detection electrode for detecting the reception level is provided for each detection electrode. There is no need to output an AC detection signal. Accordingly, since the two-dimensional input operation position can be detected only by scanning for detecting the reception level of each detection electrode, the detection cycle can be further shortened.

  In addition, the primary DC power supply circuit and the second capacitor are operated by using the first inductor and the first capacitor or the second inductor and the second capacitor that operate the first detection circuit to change the potential of each detection electrode and the input operation body. A low-pass filter that cuts off high-frequency noise between the secondary DC power supply circuits can be formed.

  According to the invention of claim 5, the input operation position of the input operation by the single input operation body that is not the multi-touch operation can be detected at high speed and with high accuracy.

  When a multi-touch operation is detected, the reception level is detected for each crossing position of the detection electrodes, so that it is possible to accurately detect each input operation position of the multi-touch operation without causing a ghost problem.

  In addition, it is possible to detect a multi-touch operation before the input operation body touches the input operation surface, and to quickly switch to an input operation position detection method that does not cause a ghosting problem.

1 is a block diagram showing a capacitive touch panel 1 according to an embodiment of the present invention. 2 is a block diagram illustrating a configuration of a main part of the capacitive touch panel 1. FIG. FIG. 4 is an equivalent circuit diagram of the reference power supply circuit 4 and the vibration power supply circuit 3 when the first AC detection signal SG is output. 3 is an equivalent circuit diagram showing a relationship between an output level Vs of a first AC detection signal SG and a reception level Vi appearing on the detection electrode 10. FIG. 4 is a flowchart illustrating a process of detecting an input operation position of the capacitive touch panel 1. It is a block diagram explaining the operation | movement by the self-capacitance system of the conventional electrostatic capacitance type touch panel 100. FIG. It is a block diagram explaining the operation | movement by the mutual capacitance system of the conventional electrostatic capacitance type touch panel 100. FIG.

  A configuration of a capacitive touch panel (hereinafter referred to as a touch panel) 1 according to an embodiment of the present invention will be described with reference to FIGS. As shown in FIG. 1, main circuit components constituting the touch panel 1 include a DC power supply 16 that applies a DC voltage Vcc to a reference power supply circuit 4 including a low-voltage reference power supply line GND and a high-voltage reference power supply line VCC that are ground potentials; Non-vibration circuit components composed of other circuit components such as capacitors 17 and 18 connected to the low-voltage reference power supply line GND and the high-voltage reference power supply line VCC, and the vibration side circuit indicated by the broken line in FIG. It is divided into vibration circuit components mounted on the substrate 2.

  The vibration side circuit board 2 is provided with a vibration power supply circuit 3 including a low-voltage vibration power supply line SGND and a high-voltage vibration power supply line SVCC. The low-voltage vibration power supply line SGND is connected to the low-voltage reference power supply line GND, and the high-voltage vibration power supply line SVCC is connected to the high-voltage reference power supply line VCC via the coils 5 and 6, respectively. The inductances of the coil 5 and the coil 6 are both set to a value that becomes high impedance with respect to a first AC detection signal SG having a natural frequency f described later. Here, the coils 5 and 6 having the same inductance L are used. Yes. As a result, as shown in FIG. 1, when the first AC detection signal SG having the natural frequency f is synchronously output to the low-voltage reference power supply line GND and the high-voltage reference power supply line VCC of the reference power supply circuit 4, the reference power supply circuit 4 Since the low-voltage reference power line GND is grounded and has a stable potential, the potentials of the low-voltage vibration power line SGND and the high-voltage vibration power line SVCC of the vibration power circuit 3 fluctuate synchronously with the natural frequency f, and the voltage between them Vibrates while maintaining the same DC output voltage Vcc as the reference power supply circuit 4.

  As shown in FIG. 2, the vibration circuit board 2 to which the vibration power supply circuit 3 is wired has a large number of X detection electrodes 10X (10) wired in the Y direction and a large number of Y detection electrodes wired in the X direction. 10Y (10) is connected to one of the low-voltage vibration power supply line SGND and the high-voltage vibration power supply line SVCC of the vibration power supply circuit 3 via the diode 7, here the low-voltage vibration power supply line SGND. A large number of X detection electrodes 10X and Y detection electrodes 10Y are arranged so as to be insulated from each other along a surface serving as an input operation surface of the vibration side circuit board 2 or an insulating panel provided separately, and an operator is a finger 20 as an input operation body. When the input operation is performed toward the input operation surface, one or more detection electrodes 10X and the Y detection electrode 10Y are arranged on the entire input operation surface so as to face or approach the finger 20.

  The vibration side circuit board 2 further includes an X side analog multiplexer XMUX for switching the connection of the X detection electrode 10X, a Y side analog multiplexer YMUX for switching the connection of the Y detection electrode 10Y, and an output side of the multiplexer MUX via the amplifier circuit 8. The A / D converter ADC to be connected, the transmission circuit 11 for transmitting the first AC detection signal SG as shown in FIG. 1, the switching control circuit 12 for switching control of the connection of the analog multiplexer, and the second AC detection signal to the X detection electrode 10X. A CPU 9 including an electrode drive circuit 13 for transmitting SG ′, a coordinate calculation circuit 14, an interface circuit 15 and the like is mounted, all of which are connected to the low-voltage vibration power supply line SGND and the high-voltage vibration power supply line SVCC of the vibration power supply circuit 3, It operates by receiving the output voltage Vcc from the power supply 16.

  The output side of the transmission circuit 11 is bifurcated and connected to the low-voltage reference power line GND and the high-voltage reference power line VCC via capacitors 17 and 18 respectively. Since the capacitor 17 and the capacitor 18 are interposed for the purpose of cutting off the DC voltage between the power supply lines GND and VCC to be connected, the respective capacitances are arbitrary, but here, the capacitors 17 and 18 having the same capacitance C are used. ing.

  Touch panel 1 according to the present embodiment includes any one of a first detection circuit that transmits first AC detection signal SG from transmission circuit 11 and a second detection circuit that transmits second AC detection signal SG ′ from electrode drive circuit 13. Are selectively operated, and the input operation position of the input operation body 20 is detected.

(Operation of the first detection circuit)
When operating the first detection circuit, the low-voltage reference power line GND of the reference power circuit 4 is connected to the first AC detection signal SG from the oscillation circuit 11 on the vibration power circuit 3 side via the capacitors 17 and 18 that bifurcate. Output to the high-voltage reference power line VCC. When the natural oscillation signal SG having the natural frequency f flows in the reference power supply circuit 4 and the vibration power supply circuit 7, the low voltage reference power supply line GND and the high voltage reference power supply line VCC and the low voltage vibration power supply line SGND and the high voltage vibration power supply line SVCC are close to each other. If the power supply lines are short-circuited in the band of the natural frequency f, the reference power supply circuit 4 and the vibration power supply circuit 3 of FIG. 1 are shown in the equivalent circuit diagram of FIG.

As shown in FIG. 3, since capacitors 17 and 18 having a capacitance C are connected in parallel between the output SG of the transmission circuit 11 on the vibration power supply circuit 3 side and the reference power supply circuit 4, the combined capacitance is 2C. In addition, the combined inductance of the coils 5 and 6 connected in parallel between the reference power supply circuit 4 and the vibration power supply circuit 3 is L / 2. These capacitors and inductors are connected in series in a closed circuit through which the first AC detection signal SG having the natural frequency f flows. The amplitude (level) of the first AC detection signal SG is Vi, and the reference power supply circuits at both ends of the coils 5 and 6 are connected. 4 and the voltage between the vibration power supply circuit 3 is Vs, and the angular velocity represented by 2πf is ω (rad / sec),
Vs = [ω ² LC / (ω ² LC-1)] Vi (1).
Here, the circuit shown in FIG. 3 resonates in series at ω ² LC = 1, and the frequency f _{0 at} that time is
f ₀ = 1 / [2π (LC) ^1/2 ] (2).

That is, if the resonance frequency f ₀ obtained from the relationship of the expression (2) is the natural frequency f of the first AC detection signal SG, the theory from the expression (1) is obtained with respect to the output level Vs of the first AC detection signal SG. The potential of the upper vibration power supply circuit 3 vibrates at infinity, and the potential of the detection electrode 10 connected to the vibration power supply circuit 3 can also be vibrated to infinity. As a result, even if the capacitance between the detection electrode 10 and the finger 20 is as small as about 10 pF, the voltage generated between the detection electrode 10 and the finger 20 expands infinitely. The reception level Vi of the first AC detection signal SG input to the arithmetic circuit 14 increases, and the detection becomes easy.

The actual touch panel 1 does not resonate at the frequency f ₀ obtained from the equation (2) due to the influence of the inductance and stray capacitance of the reference power supply circuit 4 and the vibration power supply circuit 3, and the reference power supply circuit 4 and the vibration power supply circuit 3 Due to an energy loss or the like when the first AC detection signal SG flows, the vibration power supply circuit 3 vibrates with an amplitude expanded to a finite magnification with respect to the output level Vs of the first AC detection signal SG. On the other hand, since a large voltage cannot be applied to the detection electrode 10 that the operator's finger 20 may touch, the natural frequency f of the first AC detection signal SG is shifted around the resonance frequency f ₀ or the first AC detection is performed. By adjusting the amplitude of the signal SG, the amplitude of the voltage oscillation of the detection electrode 10 is limited within a range in which the input operation can be reliably detected by the coordinate calculation circuit 14 of the CPU 9.

  When all the detection electrodes 10 are connected to the low-voltage vibration power supply line SGND, the potential vibrates at the natural frequency f, while the potential of the operator's finger (input operation body) 20 whose part such as a foot is grounded. Is a constant potential, in the detection electrode 10 where the finger 20 approaches and the electrostatic capacitance Cf with the finger 20 increases, a voltage signal of the natural frequency f is transmitted from the detection electrode 10 to the finger 20 via the electrostatic capacitance Cf. Is output. If this is viewed from the vibration power supply circuit 3 that vibrates at the natural frequency f, the input operation causes the potential of the detection electrode 10 that the finger 20 has approached to vibrate relatively at the natural frequency f, and is driven by the vibration power supply circuit 3. The CPU 9 can detect the potential fluctuation signal of the natural frequency f, that is, the first AC detection signal, and can detect the input operation from the reception level Vi of the first AC detection signal detected by the detection electrode 10 that the finger 20 approaches.

  The electrostatic capacitance Cm between each detection electrode 10 and the input operation body 20 is the distance between the detection electrode and the input operation body d, the dielectric constant of vacuum ε0, the relative dielectric constant ε of air is about 1, and the input operation body 20 And the detection electrode 10 is represented by Cm = ε0 · εr · s / d, and the reactance Xc of the capacitance Cm with respect to the AC detection signal is f because the natural frequency of the AC detection signal is f. From Xc = 1 / (2π · f · Cm), Xc = d / (ω · ε0 · εr · s).

FIG. 4 is an equivalent circuit diagram of the first detection circuit showing the relationship between the potential Vs between the input operating body 20 and the detection electrode 10 and the reception level Vi of the AC detection signal SG appearing on the detection electrode 10. , The output level of the AC detection signal SG, that is, the potential between the detection electrode 10 and the input operating body 20, Cp is the stray capacitance between the detection electrode 10 and the low-voltage vibration power supply line SGND, rp is the internal resistance value of the detection electrode 10, R4 is the resistance value of the output resistance. In the equivalent circuit diagram in the figure,
i1 = i2 + i3 (3) Formula Vs = i1 / (jω · Cm) + i2 / (jω · Cp) (4) Formula −i2 / (jω · Cp) + i3 · rp + i3 · R4 = 0 -(5) Formula i3 * R4 = Vi ... The relationship of Formula (6) is established, and from Formula (3) to Formula (6),
Vi = [jω · Cm / {1 / R4 + jω (Cm + Cp) (rp / R4 + 1)}] · Vs (7) Equation (7) is obtained.

If the internal resistance rp is set to 0, and R4 is connected to the integrating operational amplifier 8 through the multiplexer MUX, it is assumed that it is infinite.
Vi = Cm / (Cp + Cm) · Vs
Since the electrostatic capacitance Cm is extremely small, such as several tens of fF, compared to the floating capacitance Cp of several tens of pF, the equation (7) is further expressed by the following equation: Vi = (Cm / Cp) · Vs (8) expressed.

As described above, Cm of the input operating body 20 and the detection electrode 10 is expressed by Cm = ε0 · εr · s / d. Therefore, if this is substituted into the equation (8) and transformed,
Vi = {ε0 · εr · s / (d · Cp)} Vs (9) Assuming that the facing area s between the finger 20 and the detection electrode 10 does not substantially change during the input operation, (9) Since (ε0 · εr · s / Cp) in the equation is a constant, if this is set to 1 / k, the reception level Vi of the first AC detection signal SG appearing on the detection electrode 10 is
Vi = Vs / (d · k) (Expression (10)), and the detection level of the detection electrode 10 that is closer to the finger 20 is closer to the output level Vs of the first AC detection signal SG. Value. However, when the finger 20 is close to the detection electrode 10 and the electrostatic capacitance Cm between them is larger than the stray capacitance Cp of several tens of pF, the expression (10) cannot be applied and the reception level Vi. Becomes a maximum output level Vs.

  If Expression (10) is used, the distance d between each detection electrode 10 and the finger 20 can be directly obtained from the reception level Vi of the first AC detection signal appearing on each of the plurality of detection electrodes 10, and this embodiment Then, the input in the XY directions parallel to the input operation surface is determined from the arrangement positions of all the detection electrodes 10 (X detection electrode 10X, Y detection electrode 10Y) switched by the multiplexer MUX and the reception level Vi detected from each detection electrode 10. A three-dimensional input operation position of the operation position (x, y) and the input operation position z in the Z direction orthogonal to the input operation surface is detected.

  In order to detect this input operation position (x, y, z), the switching control circuit 12 of the CPU 9 switches and controls the X-side analog multiplexer XMUX and the Y-side analog multiplexer YMUX, and all the X detection electrodes in one scanning cycle. The 10X and Y detection electrodes 10Y are connected to the amplification circuit 8 composed of an operational amplifier for integration for each detection electrode 10 in order. As a result, the reception level Vi of the first AC detection signal appearing on all the detection electrodes 10 is amplified by the amplifier circuit 8 and then input to the A / D converter ADC.

  The A / D converter ADC samples at a frequency at least twice the natural frequency f of the first AC detection signal SG, quantizes the reception level Vi of the first AC detection signal SG, and outputs it to the coordinate calculation circuit 14 of the CPU 9. To do.

  Since the quantized data output from the A / D converter 14 represents the reception level Vi of the first AC detection signal SG appearing at the detection electrode 10 that is selectively connected by the analog multiplexer MUX at that time, the coordinate calculation for detecting the input operation position In the circuit 14, the total sum of the quantized data input from the A / D converter ADC during the connection period in which the detection electrode 10 is connected to the amplifier circuit 8 is compared with a predetermined threshold, and input when it is equal to or higher than the predetermined threshold. It determines with the detection electrode 10 which the operating body 20 approached. Using the received level Vi of the first AC detection signal SG detected from the determined detection electrode 10, the distance d between the arrangement position of the detection electrode 10 and the input operation body 20 can be obtained from the equation (10). The two-dimensional input operation position on the input operation surface and / or the input operation surface from the arrangement position of the plurality of detection electrodes 10 in the X or Y direction on the input operation surface and the reception level Vi. A three-dimensional input operation position including the height in the Z direction is detected.

When the coordinate calculation circuit 14 detects a plurality of input operation positions regardless of whether or not the input operation position is on the input operation surface during one scanning cycle, the CPU 9 receives the first signal from the transmission circuit 11. The transmission of the AC detection signal SG is stopped, and the operation is switched from the first detection circuit to the second detection circuit that detects the input operation position by the mutual capacitance method. On the other hand, unless a plurality of input operation positions are detected, it is assumed that the input operation is performed by the single input operation body 20, and the two-dimensional or three-dimensional input operation position detected by the coordinate calculation circuit 14 is transferred from the interface circuit 15 to The signal is output to a host device that uses the input operation position by USB communication, I ² C communication, or the like via the insulated signal line 19.

  In the first detection circuit, the distance d between any one of the detection electrodes 10 and the input operating body 20 is proportional to the inverse of the reception level Vi of the first AC detection signal SG detected by the detection electrode 10 ((10)). Therefore, the three-dimensional input operation position including the height in the Z direction on the input operation surface is accurately determined from the reception level Vi detected by the X detection electrode 10X and the Y detection electrode 10Y that are arranged to intersect each other in the XY direction. It can be detected.

  Further, only by detecting the reception level Vi of each detection electrode 10 by scanning corresponding to the number of wirings of the detection electrodes 10 (X detection electrode 10X and Y detection electrode 10Y) in one scanning cycle, two-dimensional on the input operation surface. Therefore, the input operation position can be detected at high speed and with low power consumption as compared with the mutual capacitance method in which all the intersections of the detection electrodes are scanned.

(Operation of the second detection circuit)
When operating the second detection circuit, the transmission of the first AC detection signal SG from the transmission circuit 11 is stopped, and the second AC detection signal SG ′ from the electrode driving circuit 13 serving as the second transmission means built in the CPU 9 is stopped. And the two-dimensional input operation position of the input operation body 20 is detected by the mutual capacitance method.

  By stopping the transmission of the first AC detection signal SG, the potential vibration of the vibration power supply circuit 3 is also stopped, but each circuit component mounted on the vibration side circuit board 2 is connected to the DC power supply 16 via the coils 5 and 6. Operates with a power source. In the second detection circuit, one of the plurality of X detection electrodes 10X or the plurality of Y detection electrodes 10Y receives the drive signal D (n) to which the second AC detection signal SG ′ is applied, and the other receives the second AC detection signal SG ′. The detection electrode S (m) for detecting the level Vi is received, and the second AC detection signal SG ′ is received at the intersections (n, m) of all the drive electrodes D (n) and the detection electrodes S (m) on the input operation surface. Detect level Vi.

  When the input operating body 20 approaches a specific intersection (n, m), at the timing when the second AC detection signal SG ′ is applied to the drive electrode D (n) at the intersection (n, m), the intersection (n M), the reception level Vi appearing on the detection electrode S (m) decreases because a part of the second AC detection signal SG ′ flows to the input operation body 20 and decreases. The two-dimensional input operation position of the input operation body 20 is detected from the wiring positions in the XY directions of the drive electrode D (n) and the detection electrode S (m) that intersect at the intersection (n, m).

  In the present embodiment, the switching control circuit 12 switches the X-side analog multiplexer XMUX to switch the electrode driving circuit 13 to each X detection electrode 10X by using the plurality of X detection electrodes 10X as the drive electrodes D (n). The second AC detection signal SG ′ is applied in order to each X detection electrode 10X. The output level Vs and the AC frequency of the second AC detection signal SG ′ are arbitrary, but here the detection circuit of the first detection circuit is shared for detection of the reception level Vi, and therefore the output level Vs of the first AC detection signal SG. And the frequency f. However, since the output levels Vs of the first AC detection signal SG and the second AC detection signal SG ′ do not necessarily coincide with each other, the electrode drive circuit 13 is replaced by the transmission circuit 11 and the first AC detection signal SG is changed to the second AC detection signal SG. You may make it apply to each X detection electrode 10X as alternating current detection signal SG '.

  While the second AC detection signal SG ′ is applied to any one of the X detection electrodes 10X (drive electrode D (n)), the switching control circuit 12 switches and controls the Y-side analog multiplexer YMUX, and the drive electrode D All the Y detection electrodes 10Y insulated and intersecting with (n) are connected in order to the amplifier circuit 8, and set as a detection electrode S (m) for detecting the reception level Vi of the second AC detection signal SG ′. As a result, the second AC detection signal SG ′ reception level Vi appearing at the detection electrode S (m) at all the intersections (n, m) is amplified by the amplifier circuit 8 and then input to the A / D converter ADC. The A / D converter ADC samples at a frequency that is at least twice the natural frequency f of the second AC detection signal SG ′, quantizes the reception level Vi of the second AC detection signal SG ′, and coordinates the CPU 9. 14 to output.

  The switching control circuit 12 of the CPU 9 repeats the same switching control during one scanning period, and sequentially receives the reception levels Vi detected at the intersections (n, m) of all the X detection electrodes 10X and the Y detection electrodes 10Y. 14 to output.

  Here, the reception level Vi detected at each intersection (n, m) represents the amount of change in mutual capacitance between the drive electrode D (n) and the detection electrode S (m) that intersect at the intersection (n, m). As the distance between the input operation body 20 and the intersection (n, m) approaches, it decreases. Therefore, the coordinate calculation circuit 14 sets the reception levels Vi detected for all the intersections (n, m) in the X direction that is the arrangement order of the X detection electrodes 10X and the Y direction that is the arrangement order of the Y detection electrodes 10Y. And an input operation is performed in the vicinity of the intersection (n, m) where the minimum value is detected, and reception is detected for the surrounding intersection (n, m) including the intersection (n, m). A two-dimensional input operation position in the XY direction is detected from the center of gravity in the XY direction of the level Vi.

  In the second detection circuit, the reception level Vi is detected for all the intersections (n, m) even in the so-called multi-touch operation in which the two fingers 20 are simultaneously touched on the input operation surface to perform the input operation. Only the intersection (n, m) at which the reception level Vi becomes the minimum value by the input operation of the finger 20 can be detected, there is no problem of ghost generation, and a plurality of two-dimensional input operation positions can be detected accurately.

The CPU 9 also sets the input operation positions for the plurality of input operation positions detected by operating the second detection circuit by USB communication, I ² C communication or the like via the signal line 19 in which the direct current is insulated from the interface circuit 15. Output to the higher-level device to be used.

  While the second detection circuit is operating, the transmission circuit 11 stops transmitting the first AC detection signal SG, and the output impedance of the transmission circuit 11 viewed from the capacitors 17 and 18 side is set to a low impedance. Therefore, a low-pass filter including coils 5 and 6 and capacitors 17 and 18 is formed between the vibration power supply circuit 3 and the reference power supply circuit 4, and each circuit component mounted on the DC power supply 16 side and the vibration side circuit board 2. High frequency noise is not transmitted to the other party.

  Hereinafter, the operation of the capacitive touch panel 1 configured as described above will be described with reference to the flowchart of FIG. In a standby state where no input operation is performed, the first detection circuit is operating (step S1). In the operation of the first detection circuit, only the potential of the vibration power supply circuit 3 is vibrated, and no current flows between the high-voltage vibration power supply line SVCC and the low-voltage vibration power supply line SGND or between the high-voltage reference power supply line VCC and the low-voltage reference power supply line GND. Therefore, it is possible to detect an input operation with very little power consumption.

  When the sum of the quantized data representing the reception level Vi detected for the specific detection electrode 10 is equal to or greater than a predetermined threshold, it is assumed that there has been an input operation approaching the input operation surface, and one scanning period Two-dimensional or three-dimensional input operation positions including the Z direction away from the input operation surface are detected from the reception levels Vi of the plurality of detection electrodes 10 in which the sum of quantized data exceeds a predetermined threshold value (step S2). .

  If the number of detection electrodes 10 in which the total sum of quantized data exceeds a predetermined threshold is less than 1 during one scanning period of step S2, it is determined that the input operation has been erroneously detected or the input operation has been completed, and the input operation is waited. Return to the state (step S1).

  Subsequently, it is determined whether the input operation position detected in step S2 is one place or a plurality of places (step S3). If a plurality of input operation positions are detected, a plurality of fingers (input operation bodies) are detected. ) The second detection circuit is activated by assuming that a multi-tap operation to bring 20 into contact with the input operation surface is attempted (step S4). If the input operation position is a single input operation position, the detected input operation is detected. After outputting the position to the host device (step S5), the process returns to step S2, and the detection of the input operation position where the first detection circuit is operated is repeated.

  That is, in step S2 in which the input operation position is detected by operating the first detection circuit, the input operation position is detected even in a so-called hover operation in which the input operation body 20 is operated while being away from the input operation surface. The multi-touch operation can be detected at the stage of the hover operation, and the second detection circuit can be activated before the input operation body 20 contacts the input operation surface. On the other hand, unless the multi-touch operation is detected, the first detection circuit operates to detect the input operation position even after the input operation body 20 touches the input operation surface, so that the two-dimensional input operation is performed at high speed and with high accuracy. The position can be detected.

  When the second detection circuit is activated in step S4, it is determined whether or not one or more input operation positions are detected within a predetermined time by the second detection circuit (step S6), and a plurality of scanning cycles are determined. If the input operation position is not detected within the predetermined repeated time, it is determined that the input operation has ended, and the process returns to the standby state of the input operation (step S1). Here, the predetermined time is set to a time slightly longer than the operation time from when the hover operation is detected by the first detection circuit until the input operation surface is touched. Thereby, even if the input operation body 20 exists in the input operation position before reaching the input operation surface which can be detected by the second detection circuit, it is not erroneously determined that the input operation has been completed.

  When one or more input operation positions are detected by the second detection circuit, all detected input operation positions are output to the host device regardless of the number of detections (step S7), and the process returns to step S6. The detection of the input operation position where the second detection circuit is operated is repeated.

  According to the present embodiment, the mutual detection type second detection circuit that does not cause a ghost problem is activated before the plurality of input operation bodies 20 intended for multi-touch operation come into contact with the input operation surface. The two-dimensional input operation position can be detected promptly without any time delay due to switching.

  In addition, according to the present embodiment, the same detection electrode 10 wired along the input operation surface is shared by the first detection circuit and the second detection circuit of the two types of detection methods, and each detection electrode 10 As the means for detecting the reception level Vi that appears, the circuit such as the Y-side analog multiplexer YMUX, the amplifier circuit 8, the A / D converter ADC, and the switching control circuit 12 is also used, so that without significant structural changes or addition of circuit parts, The first detection circuit and the second detection circuit can be selectively operated.

  Furthermore, according to the present embodiment, when the input operation position is detected by the first detection circuit, all the detection electrodes 10 are connected to the vibration power supply circuit 3 and the first input operation body 20 is collectively connected to the first operation body 20. Since it vibrates at the output level Vs of the AC detection signal SG, there is no need for drive control to apply the first AC detection signal SG for each detection electrode 10 that detects the reception level Vi, and one scanning cycle is shortened, resulting in higher speed. The input operation position can be detected. However, if the first AC detection signal SG whose relative potential varies between the detection electrode 10 and the input operation body 20 is generated, the first AC detection signal SG is detected for each detection electrode 10 that detects the reception level Vi. It may be applied, or the potential of the input operation body 20 side may be changed by the first AC detection signal SG.

  In the above-described embodiment, the input operation position of a normal input operation that is not a multi-touch operation is detected by operating the first detection circuit, but the input operation body 20 is in contact with the input operation surface. The operation operation position may be detected by operating the second detection circuit regardless of the multi-touch operation.

  The present invention is suitable for a capacitive touch panel that recognizes a multi-touch operation and detects a plurality of input operation positions.

1 Capacitive Touch Panel 3 Vibration Power Supply Circuit 4 Reference Power Supply Circuit 5 Coil (Second Inductor)
6 Coil (first inductor)
10X X detection electrode (first electrode)
10Y Y detection electrode (second electrode)
11 Transmission circuit (first transmission means)
13 Electrode drive circuit (second transmission means)
14 Coordinate operation circuit (first detection circuit, second detection circuit)
16 DC power supply (DC power supply)
17 Capacitor (first capacitor)
18 Capacitor (second capacitor)

Claims (5)

A plurality of first detection electrodes wired in a first direction along the input operation surface of the insulating substrate;
A plurality of second detection electrodes wired in a second direction intersecting the first direction along the input operation surface;
First transmission means for transmitting a first AC detection signal in which a relative potential between each detection electrode of the first detection electrode and the second detection electrode and the input operation body varies, and electrostatic between each of the detection electrodes and the input operation body. First signal detection means for detecting the reception level of the first AC detection signal appearing on each detection electrode via a capacitor, and also having the reception level of the first AC detection signal detected for each detection electrode. A first detection circuit that obtains a distance between the detection electrode and the input operation body, compares the distance between each detection electrode and the input operation body, and detects an input operation position of the input operation body;
A second transmitter for transmitting a second AC detection signal to the plurality of first detection electrodes in sequence, and a first transmitter for transmitting the second AC detection signal via a capacitance between the first detection electrode and the second detection electrode; First detection electrode having a second signal detection means for detecting a reception level of the second AC detection signal appearing on each of the plurality of second detection electrodes intersecting with the detection electrode, wherein the input operation body approaches and the reception level changes. And a second detection circuit for detecting an input operation position of the input operation body on the input operation surface from an intersection position of the second detection electrode on the insulating substrate;
Determination means for determining a multi-touch operation when the first detection circuit detects an input operation position by two or more input operation bodies;
A switching control circuit for switching to the operation of either the first detection circuit or the second detection circuit according to the determination result of the determination means;
If the determination means does not determine multi-touch operation, the first detection circuit is operated to detect the input operation position of the input operation body on the input operation surface,
A capacitive touch panel, wherein when the determination means determines that the operation is a multi-touch operation, the second detection circuit is operated to detect input operation positions of two or more input operation bodies on the input operation surface, respectively. . The determining means determines that the operation is a multi-touch operation when the input operation position of two or more input operation bodies is detected before the first detection circuit detects the input operation position of the input operation body on the input operation surface. The capacitive touch panel device according to claim 1. The switching control circuit switches the operation from the first detection circuit to the second detection circuit when the determination unit determines that the operation is a multi-touch operation, and the second detection circuit performs an input operation on any input operation body on the input operation surface. The capacitive touch panel device according to claim 1, wherein when the position is not detected, the operation is switched from the second detection circuit to the first detection circuit. The first detection circuit further includes a primary DC power supply circuit that outputs a DC voltage between the low-voltage reference power supply line and the high-voltage reference power supply line, one of which is grounded or at a constant potential.
A secondary DC power supply circuit that outputs a DC voltage from between the low-voltage vibration power supply line and the high-voltage vibration power supply line;
A first inductor connected between the low-voltage reference power line and the low-voltage vibration power line and having a high impedance with respect to the first AC detection signal;
A second inductor connected between the high-voltage reference power line and the high-voltage vibration power line and having a high impedance with respect to the first AC detection signal;
First transmission means operating in the secondary DC power supply circuit, and a first capacitor and a second capacitor connected between the high-voltage reference power line and the low-voltage reference power line, respectively.
While operating the first detection circuit,
The operation of the second transmission means is stopped, and the first transmission detection signal is output from the first transmission means to the primary DC power supply circuit via the first capacitor and the second capacitor,
Each of the detection electrodes is connected to one of the low-voltage vibration power line and the high-voltage vibration power line of the secondary DC power circuit and vibrated at the frequency of the first AC detection signal,
While operating the second detection circuit,
While outputting a 2nd alternating current detection signal in order from a 2nd transmission means to a plurality of 1st detection electrodes,
4. The output of the first AC detection signal of the first transmission means is stopped by setting the output impedance viewed from the first capacitor and the second capacitor of the first transmission means to be low impedance. The capacitive touch panel according to item 1. An input operation is performed on each detection electrode of the plurality of first detection electrodes wired in the first direction along the input operation surface of the insulating substrate and the plurality of second detection electrodes wired in the second direction intersecting the first direction. A first alternating current detection signal whose relative potential with the body fluctuates is transmitted,
Detecting the reception level of the first AC detection signal appearing on each detection electrode via the capacitance between each detection electrode and the input operation body;
Based on the reception level of the first AC detection signal detected for each detection electrode, the distance between the detection electrode and the input operation body is obtained, and the distance between the detection electrode and the input operation body is compared with the input operation body. The input operation position of
When the input operation position by a single input operation body is detected until the detected input operation position reaches the input operation surface, the input operation position of the input operation body on the input operation surface is detected,
When the input operation position by two or more input operation bodies is detected before the detected input operation position reaches the input operation surface, the transmission of the first AC detection signal is stopped and the plurality of first detection electrodes are sequentially arranged. Send the second AC detection signal,
The reception level of the second AC detection signal appearing on each of the plurality of second detection electrodes that intersects the first detection electrode that has transmitted the second AC detection signal via the capacitance between the first detection electrode and the second detection electrode. Detect
An input operation position of the input operation body on the input operation surface is detected from an intersection position on the insulating substrate of the first detection electrode and the second detection electrode at which the input operation body approaches and the reception level changes. An input operation position detection method for a capacitive touch panel.

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