JP4889833B2 - Capacitive touch panel inspection device and inspection method - Google Patents

Description

  The present invention relates to an inspection apparatus and an inspection method for inspecting defects in a touch panel, and more particularly, to an inspection apparatus and an inspection method applicable to a capacitive touch panel.

  In recent years, many touch panels have been used as input devices for electronic devices such as bank ATMs, portable information terminals, car navigation systems, and multifunction devices. These touch panel types include a resistive touch panel that detects changes in the voltage of a transparent electrode with resistance, an optical touch panel that measures changes in the current flowing through the photosensor, and the capacitance between the human body and the detection electrode. Conventionally, a capacitive touch panel or the like for detecting a change is known. The principle of these touch panels is to detect a change in electrical characteristics that occurs upon contact. Therefore, when inspecting the touch panel, it is usually necessary to check whether there is an abnormality in the change in the electrical characteristics.

  For example, in the inspection of a resistance film type touch panel, a voltage is applied to a pair of resistance films constituting the resistance film type touch panel, and an output voltage value (resistance value) corresponding to a predetermined input position is measured. When the output voltage value is less than or equal to a predetermined threshold, the polarity of the voltage applied to the resistance film is switched. By this series of operations, the electrical characteristics (resistance value) of the resistive touch panel are measured, and it can be determined whether the product is a non-defective product or a defective product (see, for example, Patent Document 1).

  In the inspection of the optical touch panel, light irradiation / non-irradiation is performed on a predetermined region of the photosensor formed on the array substrate. By this operation, the electrical characteristics (current value) of the photosensor are measured, and it can be determined whether the product is a non-defective product or a defective product (see, for example, Patent Document 2).

  Although the above Patent Document 1 and Patent Document 2 are different in “voltage value (resistance value)” and “current value” as electrical characteristics to be measured, both are common in that the touch panel conduction state is observed. . Then, even in a capacitive touch panel, which has been in increasing demand in recent years, it is conceivable to measure a conduction state such as a resistance value when inspecting whether the product is a good product or a defective product.

JP 2005-274225 A JP 2008-310374 A

  However, since the capacitive touch panel captures the state and location touched with a finger or the like as a slight change in capacitance (about several pF), it has the same resistance value and current value as in Patent Document 1 and Patent Document 2. It is practically impossible to confirm the abnormality electrically.

  On the other hand, in the inspection of the capacitive touch panel, it is conceivable to measure the conduction state in a state where the capacitive touch panel is mounted on a controller (control IC). In this case, a minute change in capacitance of the capacitive touch panel is indirectly measured on the controller side. However, in this case, even if there is some problem on the controller side, it is determined as a whole that the capacitive touch panel and the controller are defective. For this reason, it is desired for the touch panel manufacturer to perform the inspection with the touch panel alone before mounting the capacitive touch panel on the controller.

  Further, there is a problem that the capacitive touch panel is easily affected by external noise and the like. For this reason, it is also difficult to accurately measure changes in electrical characteristics such as voltage and current accompanying contact. Since a capacitance type touch panel is usually provided with a large number of detection electrodes, it is difficult to determine whether the detection result really corresponds to a portion (pad) to be inspected.

  Furthermore, since the sensor surface of the touch panel is an important part of the touch panel, there is a strong demand from touch panel manufacturers to avoid touching the sensor surface directly with the inspection device even for inspection purposes.

  Thus, at present, an inspection apparatus and an inspection method that can reliably inspect a capacitive touch panel have not yet been developed. The present invention has been made in view of the above problems, and an object thereof is to provide an inspection apparatus and an inspection method that can be suitably applied to a capacitive touch panel.

A characteristic configuration of a capacitive touch panel inspection device according to the present invention for solving the above-described problems is a capacitive touch panel inspection device including a plurality of electrodes, and a measurement target electrode to be inspected and Monitoring means for monitoring the voltage across the capacitance between the specific counter electrode of the counter electrodes opposed to the measured electrode, and determining means for determining the state of the measured electrode based on the monitoring result And signal input means capable of individually inputting signals to the plurality of electrodes, wherein the signal input means inputs an inspection pattern signal to the measured electrodes, and the measured electrodes and the inputs a pulse signal synchronized with the test pattern signal to the electrodes other than the specific counter electrode, wherein the said pulse signal and said test pattern signal and not waveforms potential change, their The difference of the potential difference between the issue by zero is to forcibly zero the potential difference between the counter electrodes other than the specific counter electrode and the measured electrode.

  As explained in the background art section, in a capacitive touch panel, the state and location touched with a finger or the like are captured as a slight change in capacitance (about several pF), and thus conduction It was difficult to confirm the state as an abnormal resistance value or current value. In addition, since the capacitive touch panel is easily affected by external noise or the like, it is difficult to determine whether it corresponds to a part (pad) to be inspected even if a detection result is obtained. Furthermore, since the sensor surface of the touch panel is an important part, there is a strong demand to avoid touching the sensor surface directly with an inspection device even for inspection purposes.

  In this respect, the capacitance touch panel inspection device of this configuration employs a method of monitoring the voltage across the capacitance between the electrode to be measured and the counter electrode. In the capacitive touch panel, the electrode to be measured and the counter electrode intersect each other in a plan view, but are separated by a predetermined distance in a sectional view. That is, both are close to each other at the intersection in plan view. In this approaching part, the electrode to be measured and the counter electrode act as a kind of capacitor, and a very small capacitance can be generated between them. Therefore, if the minute change in capacitance can be measured, the state of the electrode under measurement (for example, breakage, short circuit, etc.) can be determined. In particular, if a counter electrode (specific counter electrode) to be measured is selected from a plurality of counter electrodes, the voltage across the capacitance between the electrode to be measured and the specific counter electrode can be measured. And since the change in capacitance at the approaching part of the electrode to be measured and the specific counter electrode can be measured only by the switch operation on the control side, the capacitance type without touching the sensor surface of the touch panel directly with the inspection device The touch panel can be inspected.

  However, the problem here is that the capacitive touch panel is susceptible to external noise and the like. In other words, in order to accurately detect a minute capacitance generated at a site where the measured electrode and the specific counter electrode approach each other, electrostatic capacitance generated between the measured electrode and the counter electrode other than the specific counter electrode is detected. It is necessary to suppress the influence of capacity as much as possible.

In this regard, according to the inspection apparatus for the capacitive touch panel of this configuration, a pulse signal synchronized with the inspection pattern signal is input to the electrodes other than the electrode to be measured and the specific counter electrode , where the inspection pattern signal and To force the potential difference between the electrode under measurement and the counter electrode other than the specific counter electrode to zero by setting the pulse signal to a waveform with no potential change and setting the difference in potential difference between these signals to zero The difference in potential difference is approximately zero between the electrode to be measured and the counter electrode that is not the measurement target (V is zero at Q = CV). For this reason, the potential difference between the electrode to be measured and the other counter electrode can be reduced. As a result, in addition to the capacitance generated between the electrode to be measured and the specific counter electrode, the influence of the extra capacitance generated between the electrode to be measured and the other counter electrode is suppressed, and accurate measurement can be performed. .

  In the inspection apparatus for a capacitive touch panel according to the present invention, the determination unit includes a continuity determination unit that determines a continuity state of the electrode to be measured, and the time for the voltage across the capacitance to reach the reference voltage is determined. When the continuity determination unit determines that the measured electrode is not in a conductive state based on the change, the monitoring unit preferably changes the specific counter electrode to another counter electrode.

  According to the inspection apparatus of the capacitive touch panel of this configuration, when it is determined that the electrode to be measured is not in the conductive state, the monitoring unit changes the counter electrode to another counter electrode. A counter electrode that is in a conductive state can be determined between the counter electrode that is not in a conductive state and the electrode to be measured. As a result, the non-conduction position of the electrode to be measured can be specifically detected.

  In the inspection apparatus for a capacitive touch panel according to the present invention, the inspection device includes a grounding unit that grounds the plurality of electrodes individually, the grounding unit grounds an electrode other than the electrode to be measured, and the signal input unit It is preferable to input an inspection pattern signal to the electrode to be measured.

  According to the inspection apparatus for a capacitive touch panel of this configuration, electrodes other than the electrode to be measured are grounded, and an inspection pattern signal is input to the electrode to be measured. Therefore, when the electrode to be measured and an electrode other than the electrode to be measured are short-circuited, current leaks to the ground through the short-circuited portion, so that the static electricity between the electrode to be measured and the electrode other than the electrode to be measured is No potential difference occurs in the capacitance. When the electrode to be measured and an electrode other than the electrode to be measured are not short-circuited, capacitance is generated between the electrode to be measured and an electrode other than the electrode to be measured. In this way, it can be determined whether or not the electrode under measurement and an electrode other than the electrode under measurement are short-circuited.

  In the capacitance-type touch panel inspection apparatus according to the present invention, the determination unit includes a short-circuit determination unit that determines a short circuit between the electrode to be measured and an electrode other than the electrode to be measured, and the grounding unit includes the grounded unit. Whether all the electrodes other than the measurement electrode are grounded, and whether the short-circuit determination unit is short-circuited between the electrode under measurement and the electrode other than the electrode under measurement based on a change in voltage between both ends of the capacitance at the time of grounding Is preferably determined.

  According to the inspection apparatus for the capacitive touch panel of this configuration, all the electrodes other than the electrode to be measured are grounded. Therefore, when the electrode to be measured is short-circuited with an electrode other than the electrode to be measured, the electrostatic charge between the electrode to be measured and the electrode other than the electrode to be measured is not charged, and the electrode to be measured is When the other electrodes are not short-circuited, electric charge is charged in the capacitance between the electrode to be measured and the electrode other than the electrode to be measured. As a result, it can be determined whether the electrode to be measured is short-circuited with an electrode other than the electrode to be measured.

  In the inspection apparatus for a capacitive touch panel according to the present invention, when the short-circuit determining unit determines that the electrode to be measured and an electrode other than the electrode to be measured are short-circuited, one earthing of the electrode is performed. It is preferable to repeat the steps until the capacitance between the electrode to be measured and the electrode other than the electrode to be measured is charged and a potential difference is generated.

  According to the capacitive touch panel inspection device of this configuration, when it is determined that the electrode to be measured and the electrode other than the electrode to be measured are short-circuited, the grounding of the electrodes is released one by one, Since it repeats until an electrostatic capacitance generate | occur | produces between electrodes other than a to-be-measured electrode, the to-be-measured electrode in a short circuit state can be specified. As a result, an electrode that is short-circuited with the electrode to be measured can be identified.

A characteristic configuration of a capacitive touch panel inspection method according to the present invention for solving the above-described problem is a capacitive touch panel inspection method including a plurality of electrodes, and includes a measurement target electrode to be inspected and A monitoring step of monitoring the voltage across the capacitance between a specific counter electrode of the counter electrodes opposed to the electrode to be measured, and a determination step of determining the state of the electrode to be measured based on the monitoring result And a signal input step of individually inputting signals to the plurality of electrodes, and in the signal input step, an inspection pattern signal is input to the electrode to be measured, and the electrode to be measured and the inputs a pulse signal synchronized with the test pattern signal to the electrodes other than the specific counter electrode, and wherein the said test pattern signal and the pulse signal not waveforms potential change, its By the difference of potential between et signals to zero, it is to forcibly zero the potential difference between the counter electrodes other than the specific counter electrode and the measured electrode.

  The inspection method for the capacitive touch panel of this configuration has substantially the same effect as the above-described inspection apparatus for the capacitive touch panel. That is, the method for inspecting the capacitive touch panel of this configuration employs a method of monitoring the voltage across the capacitance between the electrode to be measured and the counter electrode. In the capacitive touch panel, the electrode to be measured and the counter electrode intersect each other in a plan view, but are separated by a predetermined distance in a sectional view. That is, both are close to each other at the intersection in plan view. In this approaching part, the electrode to be measured and the counter electrode act as a kind of capacitor, and a very small capacitance can be generated between them. Therefore, if the minute change in capacitance can be measured, the state of the electrode under measurement (for example, breakage, short circuit, etc.) can be determined. In particular, if a counter electrode (specific counter electrode) to be measured is selected from a plurality of counter electrodes, the voltage across the capacitance between the electrode to be measured and the specific counter electrode can be measured. And since the change in capacitance at the approaching part of the electrode to be measured and the specific counter electrode can be measured only by the switch operation on the control side, the capacitance type without touching the sensor surface of the touch panel directly with the inspection device The touch panel can be inspected.

  However, the problem here is that the capacitive touch panel is susceptible to external noise and the like. In other words, in order to accurately detect a minute capacitance generated at a site where the measured electrode and the specific counter electrode approach each other, electrostatic capacitance generated between the measured electrode and the counter electrode other than the specific counter electrode is detected. It is necessary to suppress the influence of capacity as much as possible.

In this regard , according to the inspection method of the capacitive touch panel of this configuration, a pulse signal synchronized with the inspection pattern signal is input to the electrodes other than the electrode to be measured and the specific counter electrode , where the inspection pattern signal and To force the potential difference between the electrode under measurement and the counter electrode other than the specific counter electrode to zero by setting the pulse signal to a waveform with no potential change and setting the difference in potential difference between these signals to zero The difference in potential difference is approximately zero between the electrode to be measured and the counter electrode that is not the measurement target (V is zero at Q = CV). For this reason, the potential difference between the electrode to be measured and the other counter electrode can be reduced. As a result, in addition to the capacitance generated between the electrode to be measured and the specific counter electrode, the influence of the extra capacitance generated between the electrode to be measured and the other counter electrode is suppressed, and accurate measurement can be performed. .

  In the inspection method for a capacitive touch panel according to the present invention, in the determination step, a continuity determination step of determining a continuity state of the electrode to be measured is performed, and a time during which the voltage across the capacitance reaches a reference potential When it is determined in the continuity determination step that the measured electrode is not in the continuity state based on the change of the above, it is preferable that the counter electrode is changed to another counter electrode in the monitoring step.

  The inspection method for the capacitive touch panel of this configuration has substantially the same effect as the above-described inspection apparatus for the capacitive touch panel. That is, according to the inspection method of the capacitive touch panel of this configuration, when it is determined that the electrode to be measured is not in a conductive state, in the monitoring process, the counter electrode is changed to another counter electrode. It is possible to determine a counter electrode that is in a conductive state between a counter electrode that is not in a conductive state and a measured electrode. As a result, the non-conduction position of the electrode to be measured can be specifically detected.

  The inspection method of the capacitive touch panel according to the present invention includes a grounding step of individually grounding the plurality of electrodes. In the grounding step, the electrodes other than the electrodes to be measured are grounded, and the signal input step In the above, it is preferable to input an inspection pattern signal to the electrode to be measured.

  The inspection method for the capacitive touch panel of this configuration has substantially the same effect as the above-described inspection apparatus for the capacitive touch panel. That is, according to the inspection method of the capacitive touch panel of this configuration, electrodes other than the electrode to be measured are grounded, and an inspection pattern signal is input to the electrode to be measured. Therefore, when the electrode to be measured and an electrode other than the electrode to be measured are short-circuited, current leaks to the ground through the short-circuited portion, so that the static electricity between the electrode to be measured and the electrode other than the electrode to be measured is No potential difference occurs in the capacitance. When the electrode to be measured and an electrode other than the electrode to be measured are not short-circuited, capacitance is generated between the electrode to be measured and an electrode other than the electrode to be measured. In this way, it can be determined whether or not the electrode under measurement and an electrode other than the electrode under measurement are short-circuited.

  In the inspection method of the capacitive touch panel according to the present invention, in the determination step, a short-circuit determination step for determining a short-circuit between the electrode to be measured and an electrode other than the electrode to be measured is performed. Whether all the electrodes to be measured are grounded, and whether or not the electrodes to be measured and the electrodes other than the electrodes to be measured are short-circuited in the short-circuit determination based on a change in voltage between both ends of the capacitance at the time of grounding It is preferable to determine whether or not.

  The inspection method for the capacitive touch panel of this configuration has substantially the same effect as the above-described inspection apparatus for the capacitive touch panel. That is, according to the inspection method of the capacitive touch panel of this configuration, all the electrodes other than the electrode to be measured are grounded. Therefore, when the electrode to be measured is short-circuited with an electrode other than the electrode to be measured, the electrostatic charge between the electrode to be measured and the electrode other than the electrode to be measured is not charged, and the electrode to be measured is When the other electrodes are not short-circuited, electric charge is charged in the capacitance between the electrode to be measured and the electrode other than the electrode to be measured. As a result, it can be determined whether the electrode to be measured is short-circuited with an electrode other than the electrode to be measured.

  In the inspection method for a capacitive touch panel according to the present invention, when it is determined in the short-circuit determination step that the electrode to be measured and an electrode other than the electrode to be measured are short-circuited, grounding other than the electrode to be measured is grounded. It is preferable to remove one by one and repeat until the capacitance between the electrode to be measured and the electrode other than the electrode to be measured is charged and a potential difference is generated.

  The inspection method for the capacitive touch panel of this configuration has substantially the same effect as the above-described inspection apparatus for the capacitive touch panel. That is, according to the inspection method of the capacitive touch panel of this configuration, when it is determined that the electrode to be measured and the electrode other than the electrode to be measured are short-circuited, the grounding of the electrodes is released one by one, Since it repeats until an electrostatic capacitance generate | occur | produces between electrodes and electrodes other than a to-be-measured electrode, the to-be-measured electrode in a short circuit state can be specified. As a result, an electrode that is short-circuited with the electrode to be measured can be identified.

It is the top view which showed roughly the inspection apparatus of the capacitive touch panel of embodiment which concerns on this invention. FIG. 2 is an enlarged schematic view around a region A shown in FIG. 1. It is explanatory drawing of an electrostatic capacitance detection circuit. It is a schematic diagram which shows a test | inspection pattern signal and a pulse signal. It is a schematic diagram which shows the procedure which determines the conduction | electrical_connection state of a to-be-measured electrode. It is a schematic diagram which shows the procedure which determines the short circuit with a to-be-measured electrode and electrodes other than a to-be-measured electrode.

  With reference to FIGS. 1-6, the form for implementing this invention is demonstrated. The present invention is not intended to be limited to the configurations described in the embodiments and drawings described below, and includes configurations equivalent to those configurations.

[Capacitive touch panel inspection device]
FIG. 1 is a plan view schematically showing an inspection apparatus 100 for a capacitive touch panel 1 according to an embodiment of the present invention. In the present embodiment, the capacitive touch panel 1 to be inspected includes nine horizontal electrodes X0 to X8 and seven vertical electrodes Y0 to Y6. Then, nine lead wires a0 to a8 extend downward from the horizontal electrodes X0 to X8 in the drawing, and seven lead wires b0 to b6 extend from the vertical electrodes Y0 to Y6 to the side in the drawing, respectively. . In the capacitive touch panel 1, each of the lead wires a0 to a8 constitutes a part of each of the horizontal electrodes X0 to X8, and each of the lead wires b0 to b6 is each of the vertical electrodes Y0 to Y6. Part of it. Furthermore, each of the lead wires a0 to a8 intersects each of the lead wires b0 to b6 in a plan view, but is separated by a predetermined distance in a cross sectional view. That is, both are close to each other at the intersection in plan view. This approaching part functions as a capacitor, and electrostatic capacity can be generated.

  The inspection apparatus 100 includes a capacitance detection circuit (monitoring unit) 10 and a state determination unit (determination unit) 20 as main components. The capacitance detection circuit 10 is provided between the electrode to be measured 2 to be inspected and the counter electrode (specific counter electrode 4) to be measured among the counter electrodes 3 to be opposed to the electrode to be measured 2 (the above-described approach portion). ) Monitor the voltage across the capacitance at. The capacitance detection circuit 10 is configured to include a programmable logic device (FPGA). Since the capacitance detection circuit 10 has the FPGA function, the horizontal electrodes X0 to X8 and the vertical electrodes Y0 to Y6 can be easily switched individually. The capacitance detection circuit 10 further inputs a test pattern signal to the electrode to be measured 2 as a signal input unit for individually inputting signals to a plurality of electrodes, It functions as a signal input means for inputting a pulse signal synchronized with the inspection pattern signal to the electrodes other than the counter electrode 4. Furthermore, the capacitance detection circuit 10 functions as a grounding means for grounding a plurality of electrodes individually.

  The electrode 2 to be measured is an arbitrary electrode to be inspected among the horizontal electrodes X0 to X8 and the vertical electrodes Y0 to Y6. The counter electrode 3 is disposed so as to oppose the electrode 2 to be measured. For example, when the electrode 2 to be measured is one of the vertical electrodes Y0 to Y6, the counter electrode 3 is all of the horizontal electrodes X0 to X8. When the electrode 2 to be measured is one of the horizontal electrodes X0 to X8, the counter electrode 3 is all of the vertical electrodes Y0 to Y6. Here, for example, when Y6 is the electrode to be measured 2, the counter electrode to be measured is selected as the specific counter electrode 4 from the counter electrodes X0 to X8.

  The state determination unit 20 determines the state of the electrode 2 to be measured based on the monitoring result of the capacitance detection circuit 10. The state determination unit 20 includes a continuity determination unit 30 that determines the continuity state of the electrode under measurement 2 and a short circuit determination unit 40 that determines a short circuit between the electrode under measurement 2 and an electrode other than the electrode under measurement 2.

  In FIG. 1, a region A surrounded by a circle indicates a region where the lead wire b <b> 6 extending from the measurement electrode 2 and the lead wire a <b> 0 extending from the specific counter electrode 4 approach each other.

  FIG. 2 is an enlarged schematic view around the area A shown in FIG. (A) shows the detail around the area A. FIG. The capacitive touch panel 1 includes sensor portions c1 and c2 connected to the lead wire a0, sensor portions c3 and c4 connected to the lead wire a1, sensor portions d1 and d2 connected to the lead wire b5, Sensor parts d3 and d4 connected to the lead wire b6. The sensor parts c1 to c4 and d1 to d4 detect contact with the capacitive touch panel 1 as a change in capacitance generated between the contact object and the sensor parts c1 to c4 and d1 to d4. The contact position to the capacitive touch panel 1 is output. (B) is an enlarged perspective view of the region B shown in (a). The lead wire a0 and the lead wire b6 are close to each other. (C) is sectional drawing along the lead wire b6 of the area | region B shown in (a). Capacitance is generated between the lead wire a0 and the lead wire b6.

  FIG. 3 is an explanatory diagram of the capacitance detection circuit 10. (A) is a circuit diagram of the capacitance detection circuit 10, and (b) is an example of a graph showing a change with time of the voltage between both ends of the capacitance between the measured electrode 2 and the specific counter electrode 4. It is. The capacitance detection circuit 10 monitors the voltage across the capacitance between the measured electrode 2 and the specific counter electrode 4. The capacitance detection circuit 10 includes a line potential of the lead wires a0 to a8 (that is, a voltage between both ends of the capacitance between the horizontal electrodes X0 to X8 and the ground) and a line potential of the lead wires b0 to b6. In order to be able to monitor simultaneously (that is, the voltage between both ends of the capacitance between each vertical electrode Y0 to Y6 and the ground), the circuit configuration is integrated or a plurality of circuits are provided. Is also possible.

  The electrode to be measured 2 (for example, the lead wire b6) and the specific counter electrode 4 (for example, the lead wire a0) are connected to one input of the operational amplifier 11, and the capacitance between the electrode to be measured 2 and the specific counter electrode 4 is measured. The potential difference between the measured potential (Vm) corresponding to the voltage between both ends and the reference potential (Vref) is constantly monitored. Note that Vcc in FIG. 3A is the power supply potential of the capacitance detection circuit 10.

  Before performing the inspection, first, the switch 12 is turned on and connected to the ground, and the measured potential (Vm) of the measured electrode 2 and the specific counter electrode 4 is completely discharged so that each becomes substantially zero (discharge state) ). At this time, since the reference potential (Vref) exceeds the potential to be measured (Vm), the signal output from the operational amplifier 11 is switched from Low to High as shown in the upper part of FIG.

  Next, a potential is applied to the electrode 2 to be measured. When a potential is applied to the electrode 2 to be measured, the potential to be measured (Vm) (voltage across the capacitance) of the electrode 2 to be measured gradually rises with time. At this time, by appropriately changing the ratio between the resistance value of the first variable resistor 13 and the resistance value of the second variable resistor 14 provided between the power supply potential (Vcc) and the ground, the capacitance between both ends is changed. The voltage can be fully charged or preset to any voltage.

  When the measured potential (Vm) exceeds the reference potential (Vref), the signal output from the operational amplifier 11 is switched from High to Low. Therefore, the time t during which the High signal is output from the operational amplifier 11 required for the voltage across the capacitances of the electrode 2 to be measured and the specific counter electrode 4 to reach the reference potential (Vref) from the discharge state. Time t is reached. If the lead wire of the electrode 2 to be measured is normal (that is, a non-defective product), the time t falls within a certain range. On the other hand, if the lead wire of the electrode 2 to be measured is about to be cut, disconnected, or short-circuited with another lead wire, the time t becomes abnormally long or the voltage across the capacitance Cannot reach the reference potential (Vref), and the time t cannot be measured. Therefore, it is possible to determine whether the capacitive touch panel 1 is normal or abnormal by measuring the time t.

  In the present invention, the state determination unit 20 determines whether the capacitive touch panel 1 is normal or abnormal. The state determination unit 20 can be configured by, for example, a general-purpose personal computer.

  When the state determination unit 20 applies a potential to the electrode 2 to be measured and charges the voltage between both ends of the capacitance between the electrode 2 to be measured and the specific counter electrode 4 from the discharge state, between the both ends of the capacitance The determination is made based on whether or not the voltage reaches the reference potential (Vref) within a predetermined time range. For example, if the time for the voltage across the capacitance to reach the reference voltage is longer than a predetermined time range, it is determined that the electrode 2 to be measured is not in a conductive state. Therefore, it is found that the lead wire of the electrode 2 to be measured is about to be disconnected or disconnected.

  In addition, when the capacitance detection circuit 10 has grounded all electrodes other than the electrode 2 to be measured, the state determination unit 20 determines whether or not the state determination unit 20 is based on a change in voltage across the capacitance at the time of grounding. Then, it is determined whether or not the electrode to be measured 2 and an electrode other than the electrode to be measured 2 are short-circuited. For example, when the electrode to be measured 2 is short-circuited with an electrode other than the electrode to be measured 2, no charge is charged in the capacitance between the electrode to be measured 2 and the electrode other than the electrode to be measured 2. On the other hand, when the electrode 2 to be measured is not short-circuited with an electrode other than the electrode 2 to be measured, an electric charge is charged to the capacitance between the electrode 2 to be measured and the electrode other than the electrode 2 to be measured 2.

  Furthermore, the capacitance detection circuit 10 grounds electrodes other than the electrode to be measured 2 and inputs an inspection pattern signal to the electrode to be measured 2. When the electrode 2 to be measured and an electrode other than the electrode 2 to be measured are short-circuited, the current leaks to the ground through the short-circuit portion. No potential difference occurs in the capacitance at. When the electrode to be measured 2 and an electrode other than the electrode to be measured 2 are not short-circuited, a potential difference occurs in the capacitance between the electrode to be measured 2 and an electrode other than the electrode to be measured 2. In this way, it can be determined whether or not the electrode under measurement 2 and an electrode other than the electrode under measurement 2 are short-circuited.

  As another determination method performed by the state determination unit 20, for example, when charging the capacitance of the lead wire, the capacitance is determined based on the time when the voltage between both ends of the capacitance reaches the reference potential (Vref). The normality of the touch panel 1 can also be obtained. For example, the state determination unit 20 quantifies the time when the voltage across the capacitance reaches the reference potential (Vref). The closer the measured value is to a predetermined set value, the more normal the capacitive touch panel 1 is. Judge that there is. In this case, since the subtle state of the capacitive touch panel 1 can be known, a more precise inspection can be performed.

  The reference potential (Vref) is set to, for example, a value of 0.1 to 0.9 times the potential measured when a lead wire having a normal capacitance is fully charged. The predetermined time range is set to, for example, 0.3 to 2.0 times the time required for the capacitance of a specific part having a normal value to be charged to the reference potential (Vref). If it is within this range, it is difficult to be affected by external noise during charging, so the reproducibility of the time-dependent graph of the voltage across the capacitance in FIG. Can do.

  As described above, by using the inspection apparatus 100 of the capacitive touch panel 1 having this configuration, it is possible to measure the voltage between both ends of the capacitance between the electrode 2 to be measured and the specific counter electrode 4. And since the change of the electrostatic capacitance in the approach part of the to-be-measured electrode 2 and the specific counter electrode 4 can be measured only by control side switch operation, without touching the sensor surface of a touch panel directly with the test | inspection apparatus 100, it is static. The capacitive touch panel 1 can be inspected.

  By the way, the electrostatic capacitance type touch panel inspection apparatus 100 according to the present invention is a method for detecting a minute capacitance generated at a site where the electrode 2 to be measured and the counter electrode 3 approach each other. In order to monitor only the capacitance generated between the specific counter electrode 4, the influence of the capacitance generated between the electrode to be measured 2 and the counter electrode 3 other than the specific counter electrode 4 is suppressed as much as possible. There is a need. Therefore, in the present invention, the inspection pattern signal is input to the electrode 2 to be measured by the capacitance detection circuit 10, and the electrodes other than the electrode 2 to be measured and the specific counter electrode 4 are as shown in FIG. A pulse signal synchronized with a correct inspection pattern signal is input. As a result, the difference in potential difference between the electrode to be measured 2 and the counter electrode 3 other than the specific counter electrode 4 is substantially zero (since V is zero at Q = CV), the capacitance is reduced. There is no potential difference. As a result, in addition to the capacitance generated between the electrode to be measured 2 and the specific counter electrode 4, the influence of the extra capacitance generated between the electrode to be measured 2 and the other counter electrode 3 can be suppressed and accurate. Can be measured.

[Inspection method for capacitive touch panel]
By using the inspection apparatus 100 for the capacitive touch panel 1 of the present invention described above, the inspection method for the capacitive touch panel 1 of the present invention can be implemented. Hereinafter, as a specific example of the inspection method of the capacitive touch panel 1 of the present invention, a procedure for determining the conduction state of the electrode 2 to be measured and a procedure for determining a short circuit between the electrode 2 to be measured and the counter electrode 3 will be described. .

<First Embodiment>
FIG. 5 is a schematic diagram showing a procedure for determining the conduction state of the electrode 2 to be measured. The procedure for determining the conduction state is executed by steps 1 to 3. In FIG. 5, (a) to (c) correspond to Step 1 to Step 3, respectively. In FIG. 5, the x mark on the lead wire b <b> 6 indicates a disconnected portion of the lead wire b <b> 6.

  Step 1: The capacitance detection circuit 10 selects the lead wire b6 as the electrode to be measured 2 and the lead wire a0 as the specific counter electrode 4, and determines whether the voltage across the capacitance reaches the reference voltage within a predetermined time. Monitor whether or not. The state of the electrode 2 to be measured is determined based on the monitoring result. Here, since the reference voltage is not reached within a predetermined time, the continuity determination unit 30 determines that the measured electrode 2 is not in a conductive state with respect to the lead wire a0. The capacitance detection circuit 10 changes the specific counter electrode 4 to another counter electrode (lead wire a1).

  Step 2: The capacitance detection circuit 10 selects the lead wire a1 as the specific counter electrode 4, and monitors whether the voltage across the capacitance reaches the reference voltage within a predetermined time. Here, since the reference voltage is reached earlier than the predetermined time, the continuity determination unit 30 determines that the electrode under measurement 2 is not in a conductive state with respect to the lead wire a1. The capacitance detection circuit 10 changes the specific counter electrode 4 to another counter electrode (lead wire a2).

  Step 3: The capacitance detection circuit 10 selects the lead wire a2 as the specific counter electrode 4 and monitors whether the voltage across the capacitance reaches the reference voltage within a predetermined time. Here, since the reference voltage is reached within a predetermined time, the continuity determination unit 30 determines that the electrode 2 to be measured is in a conductive state with respect to the lead wire a2.

  As described above, the capacitance detection circuit 10 monitors whether the voltage between both ends of the capacitance between the measured electrode 2 and the specific counter electrode 4 reaches the reference voltage within a predetermined time, When the reference voltage is reached earlier than the predetermined time, the continuity determination unit 30 determines that the measured electrode 2 is not in a conductive state with respect to the specific counter electrode 4. In this way, it can be checked whether or not it is in a conductive state. Further, when it is determined that the measured electrode 2 is not in the conductive state, the specific counter electrode 4 is sequentially changed to another counter electrode, and whether or not the reference voltage is reached within a predetermined time is monitored. The counter electrode 3 that is not in conduction with the counter electrode 3 and the counter electrode 3 that is in conduction with the electrode 2 to be measured can be determined. According to the procedure shown in FIG. 5, the counter electrodes that are not in conduction with the electrode to be measured 2 are the lead wire a0 and the lead wire a1, and the counter electrodes that are in conduction with the electrode to be measured 2 are the lead wire a2. Therefore, the disconnection position can be specified on the assumption that a disconnection has occurred between the portion close to the lead wire a1 and the portion adjacent to the lead wire a2 in the lead wire b6.

Second Embodiment
FIG. 6 is a schematic diagram illustrating a procedure for determining a short circuit between the measured electrode 2 and an electrode other than the measured electrode 2. The procedure for determining the conduction state is performed by steps 1 to 3. In FIG. 6, (a) to (c) correspond to Step 1 to Step 3, respectively. In FIG. 6, black circles on the lead wire b6 indicate a short-circuit portion between the lead wire a1 and the lead wire b6.

  Step 1: The capacitance detection circuit 10 grounds all electrodes other than the electrode to be measured 2. When the electrode 2 to be measured is short-circuited with the lead wire a1, the capacitance at the time of grounding is not charged, and the potential of the electrode 2 to be measured is not charged to the reference potential (Vref). Therefore, the short circuit determination unit 40 can determine whether or not the electrode 2 to be measured and an electrode other than the electrode 2 to be measured are short-circuited.

  Step 2: When the short-circuit determining unit 40 determines that the electrode 2 to be measured is short-circuited with any electrode other than the electrode 2 to be measured, the capacitance detection circuit 10 includes the electrodes other than the electrode 2 to be measured. The ground of one electrode (for example, lead wire a0) is released. Since the electrode 2 to be measured is short-circuited to the lead wire a1, the electrostatic capacitance at the time of grounding is not charged, and the potential of the electrode 2 to be measured is not charged to the reference potential (Vref).

  Step 3: When the short-circuit determining unit 40 determines that the electrode 2 to be measured and an electrode other than the electrode 2 to be measured are short-circuited, the capacitance detection circuit 10 grounds the electrode (for example, the lead wire a1). Is released. Since the electrode 2 to be measured is short-circuited to the lead wire a1, the electrostatic capacity at the time of grounding is charged, and the potential of the electrode 2 to be measured is charged to the reference potential (Vref). As a result, it can be confirmed that the electrode 2 to be measured is short-circuited with the lead wire a1.

  Thus, if the inspection method for the capacitive touch panel of the present invention is executed, all the electrodes other than the electrode to be measured 2 are grounded. Therefore, when the electrode 2 to be measured is short-circuited with an electrode other than the electrode 2 to be measured, the electrostatic charge between the electrode 2 to be measured and the electrode other than the electrode 2 to be measured is not charged, and the electrode to be measured When 2 is not short-circuited with an electrode other than the electrode to be measured 2, electric charge is charged to the capacitance between the electrode to be measured 2 and an electrode other than the electrode to be measured 2. As a result, it can be determined whether the electrode 2 to be measured is short-circuited with an electrode other than the electrode 2 to be measured. Further, when it is determined that the electrode to be measured 2 and the electrode other than the electrode to be measured 2 are short-circuited, the electrodes are grounded one by one and between the electrode to be measured 2 and the electrode other than the electrode to be measured 2. Therefore, it is possible to identify an electrode in a short-circuited state with the electrode 2 to be measured. As a result, an electrode that is short-circuited with the electrode 2 to be measured can be specified.

[Another embodiment]
<1> In the embodiment of the present invention, the inspection device for the capacitive touch panel 1 in which the lead wires a0 to a8 (counter electrode) and the lead wires b0 to b6 (measured electrode) are close to each other in a state of being orthogonal to each other in plan view. 100 explained. However, as long as the lead wires a0 to a8 and the lead wires b0 to b6 are close to each other, capacitance can be generated. For example, the lead wires a0 to a8 and the lead wires b0 to b6 intersect at an acute angle in plan view. Inspection is also possible for the capacitive touch panel. Therefore, the present invention also includes an inspection apparatus and an inspection method performed on such a capacitive touch panel that intersects at an acute angle in plan view.

<2> In the embodiment of the present invention, when conducting a continuous inspection of a capacitive touch panel, the inspection object is sequentially moved from one lead wire in an adjacent direction to inspect all lead wires. It is also possible to register in advance a lead wire to be inspected in a computer and inspect only a specific lead wire according to the execution of the computer program. In this case, for example, inspection of lead wires with a low probability of failure can be omitted and only necessary lead wires can be inspected, so that the inspection speed can be improved while ensuring certain reliability.

<3> In the inspection apparatus and the inspection method for the capacitive touch panel according to the present invention, a large capacitance combining a plurality of capacitive touch panels by using a plurality of FPGAs and synchronizing them. It is also possible to inspect the touch panel.

<4> The capacitive touch panel inspection device and inspection method of the present invention can be suitably applied to the inspection of a capacitive touch panel, but other electronic devices utilizing changes in capacitance. It can also be used in other inspections.

  The inspection device, the inspection method, and the inspection sheet of the capacitive touch panel of the present invention can be used in the inspection of input devices of electronic devices such as bank ATMs, portable information terminals, car navigation systems, and multifunction devices. .

DESCRIPTION OF SYMBOLS 1 Capacitance type touch panel 2 Electrode to be measured 3 Counter electrode 4 Specific counter electrode 10 Capacitance detection circuit (monitoring means, signal input means, grounding means)
20 State determination unit (determination means)
DESCRIPTION OF SYMBOLS 30 Continuity determination part 40 Short circuit determination part 100 Inspection apparatus of electrostatic capacitance type touch panel

Claims (10)

An inspection apparatus for a capacitive touch panel having a plurality of electrodes,
Monitoring means for monitoring the voltage between both ends of the capacitance between the measured electrode to be inspected and a specific counter electrode of the counter electrodes opposed to the measured electrode;
Determination means for determining the state of the electrode under measurement based on a monitoring result;
Signal input means capable of individually inputting signals to the plurality of electrodes,
The signal input means inputs a test pattern signal to the electrode to be measured, and inputs a pulse signal synchronized with the test pattern signal to an electrode other than the electrode to be measured and the specific counter electrode , Then, the inspection pattern signal and the pulse signal have a waveform having no potential change, and the difference in potential difference between these signals is set to zero, so that the measured electrode and the counter electrode other than the specific counter electrode Capacitance type touch panel inspection device that forcibly sets the potential difference to zero . The determination unit includes a conduction determination unit that determines a conduction state of the electrode to be measured.
When the continuity determining unit determines that the measured electrode is not in a conductive state based on a change in time when the voltage across the capacitance reaches the reference voltage, the monitoring means sets the specific counter electrode to another The capacitance touch panel inspection device according to claim 1, wherein the inspection device is changed to a counter electrode. A grounding means for grounding the plurality of electrodes individually;
The inspection apparatus for a capacitive touch panel according to claim 1, wherein the grounding means grounds electrodes other than the electrode to be measured, and the signal input means inputs an inspection pattern signal to the electrode to be measured. The determination unit includes a short circuit determination unit that determines a short circuit between the electrode to be measured and an electrode other than the electrode to be measured.
The grounding means grounds all electrodes other than the electrode to be measured,
Based on the change in the voltage across the capacitance at the ground, according to judges claim 3 whether the short determination unit and the measured electrode and the non-measured electrode electrode are short-circuited Inspection device for capacitive touch panel. When the short-circuit determining unit determines that the electrode to be measured and an electrode other than the electrode to be measured are short-circuited, the grounding of the electrodes is released one by one, and the electrodes other than the electrode to be measured and the electrode to be measured are released. The inspection apparatus for a capacitive touch panel according to claim 4 , which is repeated until capacitance is generated between the electrodes. An inspection method for a capacitive touch panel having a plurality of electrodes,
A monitoring step of monitoring the voltage between both ends of the capacitance between the measured electrode to be inspected and a specific counter electrode of the counter electrodes opposed to the measured electrode;
A determination step of determining the state of the electrode under measurement based on a monitoring result;
A signal input step of individually inputting signals to the plurality of electrodes,
In the signal input step, an inspection pattern signal is input to the electrode to be measured, and a pulse signal synchronized with the inspection pattern signal is input to an electrode other than the electrode to be measured and the specific counter electrode , Then, the inspection pattern signal and the pulse signal have a waveform having no potential change, and the difference in potential difference between these signals is set to zero, so that the measured electrode and the counter electrode other than the specific counter electrode Inspection method for capacitive touch panel that forcibly sets the potential difference of the capacitor to zero . In the determination step, a conduction determination step for determining a conduction state of the electrode to be measured is performed,
Based on the change in the time at which the voltage across the capacitance reaches the reference potential, in the continuity determination step, when it is determined that the measured electrode is not in the continuity state, the specific counter electrode is The method for inspecting a capacitive touch panel according to claim 6 , wherein the method is changed to another counter electrode. Including a grounding step of individually grounding the plurality of electrodes;
The method for inspecting a capacitive touch panel according to claim 6 , wherein an electrode other than the electrode to be measured is grounded in the grounding step, and an inspection pattern signal is input to the electrode to be measured in the signal input step. . In the determination step, a short-circuit determination step for determining a short-circuit between the measured electrode and an electrode other than the measured electrode is performed,
In the grounding step, all the electrodes other than the electrode to be measured are grounded,
Based on the change in the voltage across the capacitance at touchdown, the in short judgment step, to claim 8 for determining whether or not the the said other than the measurement electrode electrode and the measuring electrode are short-circuited Inspection method of the electrostatic capacitance type touch panel of description. In the short-circuit determining step, when it is determined that the electrode to be measured and an electrode other than the electrode to be measured are short-circuited, the grounding of the electrodes is released one by one, and other than the electrode to be measured and the electrode to be measured The method for inspecting a capacitive touch panel according to claim 9 , which is repeated until capacitance is generated between the electrodes.

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