Inspection apparatus, inspection method, capacitor manufacturing method, and inspection program

Abstract

(Problem) To provide an inspection device, an inspection method, a method for manufacturing a capacitor, and an inspection program that exclude chip capacitors with a potential short lifespan that cannot be detected by conventional insulation resistance measurements. (Solution) The inspection device comprises a current measuring unit that measures the current during the charging period of the chip capacitor and the current during the insulation resistance measurement period after the charging period has elapsed, a voltage measuring unit that measures the voltage applied to the chip capacitor during the charging period and the insulation resistance measurement period, and a determination unit that determines whether the chip capacitor passes or fails based on whether the current measured by the current measuring unit or the voltage measured by the voltage measuring unit during the charging period and the insulation resistance measurement period satisfies a predetermined threshold value.

Description

Technology Field

[0001] The present disclosure relates to an inspection device, an inspection method, a method for manufacturing a capacitor, and an inspection program. Background Technology

[0002] Conventionally, as a method for determining the acceptance of chip capacitors such as Multi-Layer Ceramic Capacitors (MLCCs), a specified voltage is applied to the chip capacitor to charge it with a constant current, and after reaching the specified voltage and a certain period of time has passed, the leakage current flowing through the chip capacitor is measured. Those exceeding the specified current value are classified as rejected (defective) products and excluded. However, it is known that among accepted products (good products), i.e., chip capacitors judged to have a leakage current lower than the specified value, there are rarely some that have a short lifespan as electronic components. Therefore, determining how to exclude such chip capacitors with short lifespans from the accepted products has been a major challenge in quality control. It is believed that the phenomenon of a shorter lifespan (e.g., the deterioration of electrical characteristics over time occurring sooner than expected) while having insulation resistance equivalent to that of accepted products during inspection is caused by internal cracks.

[0003] When a specified voltage is applied to a chip capacitor, the power supply for voltage application is equipped with a current limiter (e.g., about 30 to 50 mA), and the power supply performs constant current charging at that current value. In the case of a film capacitor, the voltage rises linearly during constant current charging, but since chip capacitors have voltage dependence on capacitance (the capacitance is smaller when the voltage is high), the curve of the voltage rise becomes curved. There is a method to monitor a sudden voltage drop by observing that curve and the voltage after the end of charging (Patent Document 1).

[0004] For example, there is a method to detect spike-shaped voltage drops that occur when temporary insulation breakdown is self-repaired. Specifically, at the point of insulation breakdown, the voltage drops momentarily because current is discharged during the breakdown (when the discharge current exceeds the current limiter). However, once the breakdown site burns away due to the discharge energy and separates from the surroundings, it self-repairs, and the voltage rises back to the normal value. Nevertheless, after repair, defects such as cracks may develop, which can cause a shortened lifespan. Therefore, by detecting this spike-shaped voltage drop, it is possible to identify components with a short lifespan.

[0005] In addition, there is a method of monitoring spike-shaped current increases by observing the leakage current flowing through the chip capacitor after applying a specified voltage. Similar to voltage, if a temporary insulation failure occurs within the chip capacitor, the leakage current increases; however, the current returns to its original normal value through self-repair caused by shocks such as heat generation resulting from the current increase. Likewise, after repair, defects such as cracks may develop, which can cause a shortened lifespan. Therefore, by detecting this increase in current, it is possible to detect a short lifespan. Prior art literature

[0006] Japanese Patent Publication No. 2000-228338 The problem to be solved

[0007] In cases where insulation breakdown occurs to the extent that the voltage fluctuates, the current flowing through the chip capacitor may exceed the limiting current of the power supply, but depending on the degree of insulation breakdown, such a large current does not flow. In short, because the voltage does not change or the amount of change is small due to slight insulation breakdown, there are cases where defects cannot be detected by the inspection method based on observing the aforementioned voltage.

[0008] Furthermore, in the latter method of observing the rise in the spike shape of the leakage current, if the normal current supplied to the chip capacitor, such as during the initial charging phase, is large, the current cannot be measured because it exceeds the maximum value of the ammeter's measurement range. If the current readings exceeding the maximum value of each range are in a saturated state, it becomes impossible to determine whether an abnormality has occurred in the current value, making accurate measurement impossible.

[0009] In addition, since most of the initial leakage current flowing through the chip capacitor is due to dielectric absorption, it decreases over time, and after a certain period, the saturation of the current reading is resolved, making it possible to measure the current. However, since it is impossible to measure (acquire) the current value during the time when the current reading is saturated after voltage is applied, it was impossible to detect current abnormalities during this period. Furthermore, during the period when the normal insulation resistance of the chip capacitor is measured, spike-shaped voltage drops or current rises occur after they have already happened, and spike-shaped waveforms cannot be detected during that period.

[0010] The present disclosure aims to provide an inspection device, an inspection method, a method for manufacturing a capacitor, and an inspection program for excluding chip capacitors that may have a short lifespan and cannot be detected by conventional insulation resistance measurements. means of solving the problem

[0011] The inspection device related to the present disclosure comprises a current measuring unit that measures the current during the charging period of the chip capacitor and the current during the insulation resistance measurement period after the charging period has elapsed, a voltage measuring unit that measures the voltage applied to the chip capacitor during the charging period and the insulation resistance measurement period, and a determination unit that determines whether the chip capacitor passes or fails based on whether the current measured by the current measuring unit or the voltage measured by the voltage measuring unit satisfies a predetermined threshold value during the charging period and the insulation resistance measurement period.

[0012] The inspection method related to the present disclosure comprises: a process of measuring a current during a charging period of a chip capacitor and a current during an insulation resistance measurement period after the charging period has elapsed, by means of a current measuring circuit; a process of measuring a voltage applied to the chip capacitor during the charging period and the insulation resistance measurement period, by means of a voltage measuring circuit; and a process of determining whether the chip capacitor passes or fails, by means of a judgment circuit, based on whether the current measured by the current measuring circuit or the voltage measured by the voltage measuring circuit satisfies a predetermined threshold value during the charging period and the insulation resistance measurement period.

[0013] A method for manufacturing a capacitor related to the present disclosure comprises: a process of measuring a current during a charging period of a chip capacitor and a current during an insulation resistance measurement period after the charging period has elapsed, by means of a current measuring circuit; a process of measuring a voltage applied to the chip capacitor during the charging period and the insulation resistance measurement period, by means of a voltage measuring circuit; and a process of determining whether the chip capacitor passes or fails, by means of a judgment circuit, based on whether the current measured by the current measuring circuit or the voltage measured by the voltage measuring circuit satisfies a predetermined threshold value during the charging period and the insulation resistance measurement period.

[0014] The inspection program related to the present disclosure is an inspection program stored in a computer-executable memory medium, and includes a function of measuring the current of a chip capacitor during a charging period and the current of an insulation resistance measurement period after the charging period by means of a current measuring circuit, measuring the voltage applied to the chip capacitor during the charging period and the insulation resistance measurement period by means of a voltage measuring circuit, and determining whether the chip capacitor passes or fails according to whether the current measured by the current measuring circuit or the voltage measured by the voltage measuring circuit satisfies a predetermined threshold value during the charging period and the insulation resistance measurement period by means of a judgment circuit. Effects of the invention

[0015] According to the present disclosure, an inspection device, an inspection method, a method for manufacturing a capacitor, and an inspection program can be provided for excluding chip capacitors that may have a short lifespan and cannot be detected by conventional insulation resistance measurements. Brief explanation of the drawing

[0016] Figure 1 is a front view of an electronic component sorting device. Figure 2 is a schematic diagram of a return member. FIG. 3 is a diagram showing the operation of the transport component and the measurement terminal during the transport and measurement of the chip capacitor. Figure 4 is a block diagram of an inspection device. Figure 5 is a diagram showing the voltage waveform and current waveform of a chip capacitor during measurement. Specific details for implementing the invention

[0017] Hereinafter, embodiments of the present disclosure will be described based on the drawings. The electronic component sorting device (1) (inspection sorting device) shown in FIG. 1 is a characteristic sorter that inspects the electrical characteristics of a chip capacitor (C) (electronic component) having electrodes on at least a part of a side or plane, and classifies them according to the inspection results. The chip capacitor (C) of the present embodiment is a multilayer ceramic capacitor. The chip capacitor (C) has a rectangular shape with design dimensions such as length dimension L > width dimension W = thickness dimension T, or length dimension L > width dimension W > thickness dimension T. The chip capacitor (C) may be a so-called two-terminal capacitor, three-terminal capacitor, multi-terminal capacitor, or array capacitor having a single-sided electrode, a side electrode, or both.

[0018] FIG. 1 is a front schematic diagram of an electronic component sorting device (1). The electronic component sorting device (1) comprises a supply unit (12) that supplies a chip capacitor (C) to a disc-shaped conveying member (2) (see FIG. 2) that is rotatably supported on a base unit (111) formed on a device body (11) that is approximately rectangular in shape, a conveying unit (13) that conveys the chip capacitor (C) supplied by the supply unit (12) by the rotation of the conveying member (2), an inspection unit (14) that inspects the electrical characteristics (insulation resistance, withstand voltage, capacitance, etc.) of the chip capacitor (C) conveyed by the conveying member (2) in the conveying unit (13), and a sorting discharge unit (15) that performs sorting discharge of the chip capacitor (C) according to the inspection result by the inspection unit (14).

[0019] FIG. 2 is a schematic diagram of a carrier member (2). The carrier member (2) temporarily receives and carries a chip capacitor (C). The carrier member (2) has a plurality of receiving holes (21) (also called chip capacitor receiving holes, pockets, or through holes) on the circumference around the rotation axis (P). The receiving holes (21) are arranged in multiple rows around the rotation axis (P). FIG. 2 shows an example of the carrier member (2) having 8 rows of receiving holes (21a to 21h) (enlarged view of part A), but the receiving holes (21) may be configured in multiple rows such as 6 rows, 10 rows, or 12 rows.

[0020] The receiving hole (21) of the present embodiment is a through hole. Depending on the shape of the chip capacitor (C) or the inspection method of the inspection unit (14), the receiving hole (21) may be a rectangular hole or a round hole. In the receiving hole (21), most of the opening on the base unit (111) side is blocked by the base unit (111), and when the transport member (2) is mounted on the base unit (111), the receiving hole (21) is configured with a bottom shape. Since the receiving hole (21) is sucked in through the vacuum groove formed in the base unit (111), the chip capacitor (C) can be stably received and transported. The chip capacitor (C) of the present embodiment is received in the end direction (length direction) with respect to the receiving hole (21) (see FIG. 3).

[0021] The return member (2) rotates intermittently (or in a step shape) around the rotation axis (P) by a rotary drive device (112) (see FIG. 1) formed on the side of the base part (111). The return member (2) rotates clockwise around the rotation axis (P) when viewed from the front of FIG. 1. The electronic component sorting device (1) returns the chip capacitor (C) supplied to the return member (2) by the supply part (12) in the order of the inspection part (14) and the sorting discharge part (15).

[0022] The supply unit (12) comprises a hopper unit (121), a feeder (122) that transports a chip capacitor (C) supplied from the hopper unit (121), a shooter (123) that supplies the chip capacitor (C) supplied from the feeder (122) to a bucket (124) through a transport path (details omitted), and a bucket (124) that supplies the chip capacitor (C) supplied to the shooter (123) to a receiving hole (21) of a transport member (2).

[0023] The hopper section (121) stores chip capacitors (C) before inspection and transfers them to the feeder (122) (parts feeder). The hopper section (121) is a silo that is in the shape of an inverted triangle when viewed in cross-section, with the inner diameter width decreasing as it moves from the top to the bottom.

[0024] The feeder (122) of the present embodiment is a linear feeder that has a conveying path recessed in a straight shape on the upper side and supplies a chip capacitor (C) to a shooter (123) by vibrating the conveying path.

[0025] The shooter (123) has multiple straight-shaped conveyor paths partitioned by partition walls inside. The shooter (123) of this embodiment has eight rows of conveyor paths. These conveyor paths are tube-shaped passages arranged parallel to each other. Chip capacitors (C) supplied from the feeder (122) are supplied to which conveyor path within the shooter (123), for example, by a distribution mechanism formed on the inlet side of the shooter (123).

[0026] The bucket (124) supplies chip capacitors (C) supplied from the shooter (123) to the receiving hole (21) of the transport member (2). The bucket (124) is positioned on the front side of the transport member (2). The bucket (124) has a plurality of transport paths partitioned in each row of the receiving hole (21) (21a to 21h) of the transport member (2). Each transport path is formed to extend parallel to the arrangement direction (circumferential direction) around the rotation axis (P) of the receiving hole (21). Chip capacitors (C) supplied from the shooter (123) into the transport path of the bucket (124) are received one by one into the receiving hole (21) by the negative pressure generated within the receiving hole (21) through the base part (111).

[0027] In addition, the return path of the shooter (123), the return path of the bucket (124), and the measuring terminals (141, 142) of the measuring station described later are configured with the same number of rows as the receiving hole (21) (e.g., 6 rows, 10 rows, or 12 rows, etc.).

[0028] The inspection unit (14) has measurement terminals (141, 142) (contacts) for measuring electrical characteristics located at adjacent positions on the base portion (111) side and the opposite side of each receiving hole (21) of the return member (2) (see FIG. 3). The measurement terminals (141, 142) are electrically connected to an inspection device (3) mounted on an electronic component sorting device (1) (see FIG. 4).

[0029] Additionally, the electronic component sorting device (1) has a control device (113) that supplies a control signal regarding measurement processing to an inspection device (3). The control device (113) controls the operation of each functional part (supply unit (12), return unit (13), inspection unit (14), and classification discharge unit (15), etc.) of the electronic component sorting device (1), or acquires and determines a detection value detected by various sensors. The control device (113) is, for example, a control unit such as a personal computer, and is formed within the electronic component sorting device (1). The control device (113) is equipped with a control unit such as a CPU (i.e., a processor), a memory unit that stores data and programs (i.e., a memory medium), an input unit (e.g., a touch panel, keyboard, switch, etc.), an output unit (e.g., a display, indicator, soundproofing unit, etc.), and a communication unit (a data communication unit via wired or wireless connection, etc.).

[0030] The sorting discharge unit (15) has the function of discharging the chip capacitor (C) of the return member (2) into a recovery container (16) (also called a sorting box) according to the inspection result in the inspection unit (14). The sorting discharge unit (15) has a discharge path (151) corresponding to each sorting item at different angle positions on the return path around the rotation axis (P). The discharge path (151) is connected to a recovery container (16) corresponding to a sorting item including accepted items and rejected items.

[0031] The discharge channel (151) is a cylindrical member formed of resin or metal, etc. Also, the classification discharge section (15) has an exhaust port on the side of the base section (111). When the chip capacitor (C) is located in the discharge channel (151) connected to the recovery container (16) to be discharged, the classification discharge section (15) can classify and recover the chip capacitor (C) into the recovery container (16) corresponding to the inspection result by switching the pressure of the exhaust port of the base section (111) to ON.

[0032] Next, details of the inspection device (3) will be described. The inspection device (3) is primarily used to inspect insulation characteristics, but it may also inspect withstand voltage characteristics as long as it can determine whether the chip capacitor (C) is acceptable (good or defective, etc.) by measuring the current obtained by applying voltage. The inspection device (3) is not limited to any specific use or name as long as it has the function of the present embodiment.

[0033] The inspection device (3) is equipped with a power supply device (31) and a measuring device (32). The power supply device (31) generates and supplies a DC voltage to the measuring device (32). The measuring device (32) applies the DC current supplied from the power supply device (31) to a chip capacitor (C) to measure the current and the resistance of the chip capacitor (C), and determines whether it passes.

[0034] The power supply (31) generates a voltage to be applied to a chip capacitor (C) which is a device under test (DUT). The power supply (31) includes a rectifier circuit (311), a filter circuit (312), a constant voltage circuit (313), a constant current circuit (314), an output resistor (315), and an interlock relay (SW1).

[0035] The power voltage supplied to the power supply unit (31) through the internal power circuit from the electronic component sorting device (1) is rectified by the rectifier circuit (311) and smoothed by the filter circuit (312). The output of the filter circuit (312) is adjusted to a constant voltage and current by the constant voltage circuit (313) and the constant current circuit (314), respectively, and is supplied to the measuring device (32) through the output resistor (315) and the interlock relay (SW1).

[0036] The measuring device (32) is equipped with a current measuring unit (321), a differential waveform detection unit (322), a voltage measuring unit (323), a control unit (324), a judgment unit (325), a memory unit (326), and a communication unit (327), etc. Additionally, the measuring device (32) is equipped with, as a circuit configuration, an input terminal (T0) to which power is supplied from a power supply unit (31), a voltage application relay (SW2), a polarity switching switch (SW3), a first terminal (T1), a second terminal (T2), and a protection resistor (R).

[0037] The measuring device (32) outputs the voltage generated by the power supply (31) from the first terminal (T1) through the input terminal (T0), voltage application relay (SW2), and polarity switching switch (SW3), and applies it to the chip capacitor (C). The current flowing through the chip capacitor (C) is input from the second terminal (T2) and input to the current measuring unit (321) via the polarity switching switch (SW3) and protection resistor (R). The current measuring unit (321) is a current measuring circuit that measures the current flowing through the chip capacitor (C).

[0038] The polarity switching switch (SW3) has the function of switching the polarity of the circuit connected to the chip capacitor (C) by switching the connection between the first terminal (T1) and the second terminal (T2), and applying the voltage with reverse polarity. The switching of polarity can be arbitrarily set by the user in advance according to the inspection item of the chip capacitor (C).

[0039] Additionally, the voltage measuring unit (323) is connected to the circuit between the voltage application relay (SW2) and the polarity switching switch (SW3). The voltage measuring unit (323) is a voltage measuring circuit that measures the voltage applied to the chip capacitor (C). The outputs of the current measuring unit (321) and the voltage measuring unit (323) are both connected to the differential waveform detection unit (322).

[0040] The differential waveform detection unit (322) calculates the output values ​​of both the current measurement unit (321) and the voltage measurement unit (323) and outputs a differential value.

[0041] The judgment unit (325) acquires each detection value (current value and voltage value and their derivative values) detected by the current measuring unit (321), the voltage measuring unit (323), and the derivative waveform detection unit (322), and compares it with a predetermined threshold value to determine whether the chip capacitor (C) passes or fails based on whether it satisfies the threshold value.

[0042] For example, if the derivative value detected by the derivative waveform detection unit (322) is large, it is clear that the magnitude or rate of change (amount of change per unit time) of the spike waveform is large, and a pass / fail determination is performed by comparing it with a preset threshold value and determining that it is a failure if it is larger. The derivative value may be performed analogously, or digitally by processing data acquired from an A / D converter. The judgment unit (325) can detect the spike shape waveform of the current detected by the current measurement unit (321) or the voltage detected by the voltage measurement unit (323).

[0043] The control unit (324) executes a function and / or method realized by a code or instruction included in a program stored in the memory unit (326). The control unit (324) may, for example, be a Central Processing Unit (CPU), Micro-Processing Unit (MPU), GPU, Micro Controller Unit (MCU), processor core, multiprocessor, ASIC, FPGA, etc., and may realize each process disclosed in this embodiment by a logic circuit or dedicated circuit formed in an integrated circuit, etc. In addition, these circuits may be realized by one or more integrated circuits, and multiple processes shown in each embodiment may be realized by one integrated circuit.

[0044] The control unit (324) controls the operation of each functional unit (determination unit (325), memory unit (326), communication unit (327), etc.) of the measuring device (32), or processes the determination result of the detection value detected by various detection units (current measurement unit (321), differential waveform detection unit (322), voltage measurement unit (323), etc.). The communication unit (327) performs data communication with the control device (113) and other devices via wired or wireless means.

[0045] The control unit (113) is, for example, a control unit of a personal computer, etc., and is formed within the electronic component sorting device (1). The control unit (324) is formed in the inspection device (3) (power supply unit (31), measuring device (32)).

[0046] In addition, the measuring device (32) may also be equipped with an input section (e.g., a touch panel, keyboard, switch, etc.) and an output section (e.g., a display, indicator, soundproofing section, etc.).

[0047] Next, a method of inspection by an inspection device (3) and a method of manufacturing a chip capacitor (C) manufactured by carrying out said inspection method will be described.

[0048] In the electronic component sorting device (1) of FIG. 1, a chip capacitor (C) introduced through the supply unit (12) is received in the receiving hole (21) (see FIG. 2) of the transport member (2) which is rotatably mounted in the transport unit (13), and moves along the clockwise rotation direction around the rotation axis (P) of FIG. 1 in conjunction with the intermittent rotational movement of the transport member (2). The chip capacitor (C) is first transported to the inspection unit (14).

[0049] FIG. 3 is a diagram showing the operation of a transport member (2) and a measurement terminal (141, 142) during transport and measurement of a chip capacitor (C). FIG. 3 shows a measurement terminal (141, 142) of a measurement station placed in an inspection unit (14). The inspection unit (14) of the present embodiment has a fixed measurement terminal (142) having a contact surface that is approximately one plane with the surface of the base unit (111), and a measurement terminal (141) placed opposite to the measurement terminal (142). A probe terminal is used as the measurement terminal (141).

[0050] In the inspection section (14), a plurality of measurement stations are formed in the return direction (rotation direction of the return member (2)) to inspect a chip capacitor (C) moving in the return direction in a plurality of items. In each measurement station, a measurement terminal (141, 142) shown in FIG. 3 is arranged.

[0051] As an example of a configuration of multiple measurement stations, for instance, four stations (hereinafter referred to as IR1, IR2, IR3, and IR4) are arranged, and each performs a positive withstand voltage test (IR1), a negative withstand voltage test (IR2), a leakage current measurement based on a positive rated voltage (IR3), and a leakage current measurement based on a negative rated voltage (IR4). Although the voltage applied to the chip capacitor (C) at each measurement station is set to be arbitrarily different, the measurement and determination of voltage and current are performed in the same way at all stations. As for the set voltage, for example, IR1 applies a voltage approximately 3 to 5 times the rated voltage of the chip capacitor (C), IR2 applies the same voltage with opposite polarity to IR1, IR3 applies the rated voltage with the same polarity as IR1, and IR4 applies a voltage with opposite polarity to the same voltage as IR3.

[0052] As shown in FIG. 3(a), while the carrier member (2) is moving, the measuring terminal (141) is waiting at a position separated from the carrier member (2) so as not to come into contact with the chip capacitor (C).

[0053] In FIG. 3(b), the return member (2) stops at a position where the position of the receiving hole (21), i.e., the position of the chip capacitor (C), is between the measurement terminal (141) and the measurement terminal (142).

[0054] In FIG. 3(c), after the return member (2) stops and a predetermined delay time has elapsed, the measurement terminal (141) moves to come into contact with the chip capacitor (C) by a driving mechanism not shown (e.g., motor, air cylinder, solenoid coil, etc.). When the measurement terminal (141) comes into contact with the chip capacitor (C), the measurement circuit of FIG. 4 is formed, and an inspection is performed by the inspection device (3).

[0055] FIG. 5 is a diagram showing the voltage and current waveforms of a chip capacitor (C) during measurement. The inspection device (3) applies the voltage supplied from the power supply device (31) to the chip capacitor (C) through the measurement terminals (141, 142) connected via the measurement device (32).

[0056] First, the voltage and current waveforms when testing a normal chip capacitor (C) that is a passing product will be described. As shown in Fig. 5, in the leakage current (insulation resistance) test of the chip capacitor (C), a predetermined voltage is applied according to the performance of the chip capacitor (C), and the current value is measured at a timing (insulation resistance measurement period (Tb)) when dielectric absorption (also called polarization) and charging have progressed to a certain extent and the leakage current value has stabilized, and the insulation characteristics are evaluated based on the magnitude of that value.

[0057] The period during which voltage is applied to the chip capacitor (C) includes a charging period (Ta) and an insulation resistance measurement period (Tb) after the charging period (Ta). Additionally, the charging period (Ta) includes a constant current charging period (Ta1) and a constant voltage charging period (Ta2). The current measuring unit (321) measures the current of the chip capacitor (C) during the charging period (Ta) and the current during the insulation resistance measurement period (Tb) after the charging period (Ta). Additionally, the voltage measuring unit (323) measures the voltage applied to the chip capacitor (C) during the charging period (Ta) and the insulation resistance measurement period (Tb).

[0058] During the constant current charging period (Ta1), the inspection device (3) applies voltage to the chip capacitor (C) and performs constant current charging at a current value set by the current limiter of the power supply (31) until a predetermined voltage is reached. The limiting current (I2) of the power supply (31) (maximum current flowing through the chip capacitor (C)) is set, for example, to 2 mA to 50 mA. If the chip capacitor (C) is normal, the voltage during the constant current charging period (Ta1) increases (rises) non-linearly and monotonically, as indicated by the solid line, until the set voltage (V1) is reached.

[0059] Also, during the constant current charging period (Ta1), the limiting current (I2) is set to be larger than the full scale of the measurement range (measurable current value (I1) in FIG. 5). Therefore, during the constant current charging period (Ta1), the actual current flowing through the chip capacitor (C) cannot be observed for most of the time. For this reason, the current measuring unit (321) obtains a current value (I1) that is smaller than the limiting current (I2) as the measurement value.

[0060] Additionally, the current measuring unit (321) of the present embodiment can set the measuring range to, for example, 10 mA, 1 mA, 100 uA, 10 uA, 1 uA, 100 nA, and 10 nA. Each measuring range (full-scale current value (I1)) and limiting current (I2) can be changed according to instructions from the control unit (324) or the control device (113).

[0061] During the constant voltage charging period (Ta2), the voltage applied to the chip capacitor (C) is maintained at a constant level after reaching the set voltage (V1). At this time, the current flowing into the chip capacitor (C) decreases over time. The constant voltage charging period (Ta2) is divided into two time regions: a constant voltage current range exceeding period (Ta21) and a constant voltage current range non-exceeding period (Ta22).

[0062] The period of exceeding the constant voltage current range (Ta21) is a time period during which a current exceeding the measurement range that the current measuring unit (321) can measure flows through the chip capacitor (C). Therefore, it is a period during which the current measuring unit (321) cannot accurately measure the change in current. In the example of FIG. 5, the current flowing into the chip capacitor (C) is the limiting current (I2), but because it exceeds the measurement range, the current measuring unit (321) obtains a current value (I1) that is smaller than the limiting current (I2) as the measurement value.

[0063] The constant voltage current range non-exceeding period (Ta22) is a period during which the current within the measurement range that the current measuring unit (321) can measure flows through the chip capacitor (C), so the change in current can be accurately measured by the current measuring unit (321).

[0064] When a predetermined charging period (Ta) has elapsed, the inspection device (3) (specifically, the current measuring unit (321)) measures the leakage current of the chip capacitor (C) during the insulation resistance measurement period (Tb).

[0065] In a series of charging and measuring cycles of charging period (Ta) and insulation resistance measuring period (Tb), the chip capacitor (C) is determined by the following method by the measuring device (32) (whether it is a good product that satisfies a predefined threshold value, or a defective product that does not satisfy it).

[0066] The judgment unit (325) acquires each value of the current measured by the current measuring unit (321) or the voltage measured by the voltage measuring unit (323) during the charging period (Ta) and the insulation resistance measurement period (Tb), and determines whether the chip capacitor (C) passes or fails based on whether either of the current or the voltage satisfies a predetermined threshold value. Additionally, the determination of the current or voltage includes a process in which the judgment unit (325) acquires the derivative value of the current measured by the current measuring unit (321) and the derivative value of the voltage measured by the voltage measuring unit (323) from the derivative waveform detection unit (322), and determines whether the chip capacitor (C) passes or fails based on whether either of the derivative values ​​satisfies a predetermined threshold value.

[0067] More specifically, the judgment unit (325) determines whether the chip capacitor (C) passes based on the voltage measured by the voltage measuring unit (323) when the current detected by the current measuring unit (321) is outside the measurable range (constant current charging period (Ta1), and the constant voltage current range exceeding period (Ta21) of the constant voltage charging period (Ta2)). The judgment unit (325) determines, for example, that it fails if the voltage is less than the threshold value.

[0068] Also, the judgment unit (325) determines whether the chip capacitor (C) passes or fails based on whether the change in voltage per unit time measured by the voltage measurement unit (323) (i.e., the derivative value of the voltage detected by the derivative waveform detection unit (322)) satisfies a predetermined threshold value when the current detected by the current measurement unit (321) is outside the measurable range (constant current charging period (Ta1), and the constant voltage charging period (Ta2) exceeds the constant voltage current range (Ta21)). For example, the judgment unit (325) determines that the chip capacitor (C) fails when the derivative value of the voltage is greater than or equal to a predetermined value (or exceeds a predetermined value).

[0069] Meanwhile, the judgment unit (325) determines whether the chip capacitor (C) passes based on whether the current measured by the current measuring unit (321) or the voltage measured by the voltage measuring unit (323) or the voltage measured by the current measuring unit (321) or the voltage measured by the voltage measuring unit (323) satisfies a predetermined threshold value when the current measured by the current measuring unit (321) or the voltage measured by the voltage measuring unit (323) is within the measurable range (the period of non-excess of the constant voltage current range of the constant voltage charging period (Ta22)).

[0070] The judgment unit (325) determines that the current is greater than the threshold value or the voltage is less than the threshold value, for example, that it is a failure. Or, the judgment unit (325) determines that the current is a failure if the derivative value of the current or the derivative value of the voltage is greater than or equal to a predetermined value (or exceeds a predetermined value). In short, the judgment unit (352) determines that the current and voltage are a failure if the change amount is large.

[0071] Thus, the judgment unit (325) can determine that the chip capacitor (C) is unsuitable by detecting a spike-shaped pulse wave of the current measured by the current measuring unit (321) or the voltage measured by the voltage measuring unit (323) during the charging period (Ta).

[0072] For example, in the voltage waveform at the top of FIG. 5, the instantaneous voltage drop in the shape of a spike appearing as a waveform (P1) in the range of the constant current charging period (Ta1) and the constant voltage current range exceeding period (Ta21) cannot be accurately measured by the current measuring unit (321) as a change in current, but can be detected as an abnormal chip capacitor (C) by monitoring the voltage.

[0073] Additionally, the non-exceeding period of the constant voltage current range (Ta22) is a time period during which a current that can be measured by the current measuring unit (321) is flowing, and the judgment unit (325) is able to detect small changes in current. In the event that an insulation failure occurs due to an internal crack or other abnormality occurring inside the chip capacitor (C), the voltage may drop momentarily. Therefore, by determining it as a defective product when the magnitude of the voltage spike waveform exceeds a threshold value, the chip capacitor (C) that may have a short lifespan can be excluded.

[0074] For example, waveform (P2) is a waveform in which an abnormal current detectable in the current, but no clear abnormality appears in the voltage measurement result at the same timing. At the timing of waveform (P3) in which a spike-shaped voltage drop appears larger than a predetermined amount, a spike-shaped waveform (P4) is also observed in the current measurement result, and can be observed as an abnormal value in either the voltage or the current.

[0075] After that, during the insulation resistance measurement period (Tb), the judgment unit (325) determines that the chip capacitor (C) is unacceptable if the insulation resistance value calculated by the voltage measured by the voltage measuring unit (323) and the current measured by the current measuring unit (321) is below a predetermined threshold value. Thus, if both the spike-shaped waveform and the magnitude of the leakage current (magnitude of insulation resistance) are determined to be within the threshold value (acceptable), the chip capacitor (C) is determined to be acceptable in the inspection of the measurement station. On the other hand, if either the spike-shaped waveform or the magnitude of the leakage current (magnitude of insulation resistance) shows an abnormal value, the chip capacitor (C) is determined to be unacceptable in the inspection of the measurement station. This improves the reliability of the inspection of the chip capacitor (C).

[0076] In addition, regarding the measurement conditions for voltage and current, for example, the threshold value of the differential value of the voltage is set to a range of + and - of the applied voltage of approximately 20% to 50%. The judgment unit (325) can determine that it is unacceptable if the voltage exceeds this range. Also, the judgment threshold value of the differential value of the current is set according to the measurement range or the magnitude of the noise, and is set to a value greater than the noise so that the noise does not affect the judgment. For example, the differential value of the current can be set to a range of -10 to +10 nA / ms as the threshold value for passing. The judgment unit (325) can determine that it is unacceptable if the current exceeds this range.

[0077] In FIG. 3 (d), after the inspection of the chip capacitor (C) is finished, the measurement terminal (141) is moved away from the chip capacitor (C) by a driving mechanism not shown.

[0078] After that, in FIG. 3 (e), the return member (2) moves, and the chip capacitor (C) moves to the next measurement station (or classification discharge unit (15)). Also, the next chip capacitor (C) to be tested is returned to the location of the measurement terminals (141, 142) shown.

[0079] In addition, if both voltage and current are judged as NG, voltage may be prioritized as the defect judgment item. Also, by setting, the priority of current may be increased, or the configuration may be one that the user can decide arbitrarily.

[0080] In the above embodiment, an inspection device (3) has been described, comprising a current measuring unit (321) for measuring the current during the charging period (Ta) of the chip capacitor (C) and the current during the insulation resistance measurement period (Tb) after the charging period (Ta) has elapsed, a voltage measuring unit (323) for measuring the voltage applied to the chip capacitor (C) during the charging period (Ta) and the insulation resistance measurement period (Tb), and a judgment unit (325) for determining whether the chip capacitor (C) passes or fails based on whether the current measured by the current measuring unit (321) or the voltage measured by the voltage measuring unit (323) satisfies a predetermined threshold value during the charging period (Ta) and the insulation resistance measurement period (Tb).

[0081] In addition, a method for manufacturing a capacitor manufactured by implementing an inspection method comprising: a process of measuring the current of the chip capacitor (C) during the charging period (Ta) and the current of the insulation resistance measurement period (Tb) after the charging period by means of a current measuring circuit (current measuring unit (321)); a process of measuring the voltage applied to the chip capacitor (C) during the charging period (Ta) and the insulation resistance measurement period (Tb) by means of a voltage measuring circuit (voltage measuring unit (323)); and a process of determining whether the chip capacitor (C) passes or fails according to whether the current measured by the current measuring unit (current measuring unit (321)) or the voltage measured by the voltage measuring unit (voltage measuring unit (323)) satisfies a predetermined threshold value during the charging period (Ta) and the insulation resistance measurement period (Tb) by means of a judgment circuit.

[0082] Additionally, a configuration was described in which a test program executable by a computer (test device (3)) measures the current of the chip capacitor (C) during the charging period (Ta) and the current during the insulation resistance measurement period (Tb) after the charging period (Ta) by means of a current measurement circuit (current measurement unit (321)), measures the voltage applied to the chip capacitor (C) during the charging period (Ta) and the insulation resistance measurement period (Tb) by means of a voltage measurement circuit (voltage measurement unit (323)), and determines whether the chip capacitor (C) passes or fails based on whether the current measured by the current measurement circuit or the voltage measured by the voltage measurement circuit satisfies a predetermined threshold value during the charging period (Ta) and the insulation resistance measurement period (Tb) by means of a judgment circuit (judgment unit (325)). The test program is stored in a memory medium. Also, the inspection device (3) (computer) of the present embodiment is a program product capable of executing each process (function) when the inspection program is executed on the processor of the control device (113).

[0083] In summary, in the present disclosure, by sampling while simultaneously monitoring voltage and current, defective products are detected by changes in voltage while the current exceeds a measurable range (measurement range), and defective products are detected primarily by current after the current value enters a measurable range, thereby compensating for each other's disadvantages and enabling a higher precision determination of acceptance. By selecting and excluding these as defective products, the inclusion of short-life products among the chip capacitors selected as acceptable products can be reduced.

[0084] Until now, a method of determining defects based on whether the current value exceeds a predetermined value or not has been considered. In the inspection method of the present disclosure, by setting the amount of change in current per unit time (derivative value) as a threshold value, it is possible to set a spike-shaped waveform as a detection item for determining defects using a single parameter.

[0085] In this way, chip capacitors with a potential short lifespan that cannot be detected by conventional insulation resistance measurements can be excluded.

[0086] The description of the embodiments of the present disclosure is concluded above, but the embodiments of the present disclosure are not limited to these embodiments. For example, in the present embodiment, an inspection device (3) of an electronic component sorting device (1) that inspects and sorts multilayer ceramic capacitors as chip capacitors (C) has been described, but the electronic component sorting device (1) may be a device that inspects and sorts other chip capacitors such as single-layer ceramic capacitors.

[0087] In addition, the inspection device (3) may be mounted on other devices such as an external inspection device or a taping device to perform an inspection of the chip capacitor (C).

[0088] Also, although the judgment unit (325) has been described as an independent functional unit of the measuring device (32) for convenience, it may be formed as part of another component (e.g., control unit (324), current measuring unit (321), differential waveform detection unit (322), voltage measuring unit (323), etc.) as long as it has the function described in this embodiment, or it may be formed in other devices other than the control device (113) or the measuring device (32).

[0089] In addition, in this embodiment, a feeder (122) has a conveying path that is recessed in a straight shape on the upper side, and a chip capacitor (C) is supplied to any conveying path within the shooter (123) by a distribution mechanism formed on the inlet side of the shooter (123), but this is not limited thereto. For example, the feeder (122) may be formed by a plurality of linear feeders capable of vibrating conveying independently, and each linear feeder may individually convey the chip capacitor (C) and supply it to the conveying path of the shooter (123).

[0090] In addition, in this embodiment, an example is shown in which the measurement terminal (141) positioned opposite to the measurement terminal (142) on the base part (111) is a probe terminal, but the measurement terminal (141) may use other configurations such as a slide terminal that is always in close proximity to or in contact with the transport member (2) in a state where it can move elastically from the transport member (2) by means of an elastic member, or a roller terminal that reduces contact friction with the chip capacitor (C) by providing a rotor at the tip of the terminal. Also, the measurement terminal (141) may be in contact while the chip capacitor (C) is stopped at a measurable position, as in the inspection part (14) of this embodiment, and may perform an operation of separating after measurement, or depending on the shape of the terminal, it may be in a configuration that is always in close proximity to or in contact with the transport member (2) and does not actively move up and down with respect to the chip capacitor (C).

[0091] In addition, since there is a period during the charging period (Ta) during which the current cannot be measured, a judgment invalidation period may be provided by setting.

[0092] In addition, the inspection program of the present embodiment may be stored in a memory unit (326) or a memory unit of a control device (113) or other memory medium, and may be executed by a computer such as a measuring device (32) or a control device (113).

[0093] Also, the measurement terminals (141, 142) of FIG. 3 are shown as corresponding to a receiving hole (21) (one of the 8 receiving holes (21a to 21h)) in a certain column of a measurement station, but the measurement terminals (141, 142) can be arranged in the same way in all 8 columns and in each measurement station.

[0094] Also, in this embodiment, the judgment unit (325) is shown as an example of determining whether to pass or fail based on current or voltage or their derivative values, but instead of two stages of pass or fail, it may be determined by providing multiple stages of threshold values ​​and ranking in three or more stages.

[0095] The configuration of the present disclosure is exemplified as follows.

[0096] [1]

[0097] A current measuring unit that measures the current during the charging period of a chip capacitor and the current during the insulation resistance measurement period after the charging period has elapsed, and

[0098] A voltage measuring unit for measuring the voltage applied to the chip capacitor during the charging period and the insulation resistance measurement period, and

[0099] A determination unit that determines whether the chip capacitor passes during the charging period and the insulation resistance measurement period, depending on whether the current measured by the current measuring unit or the voltage measured by the voltage measuring unit satisfies a predetermined threshold value.

[0100] An inspection device equipped with

[0101] [2]

[0102] The above-described inspection device [1] determines whether the chip capacitor passes based on the voltage measured by the voltage measuring unit when the current detected by the current measuring unit is outside the measurable range.

[0103] [3]

[0104] The above-described inspection device [1] or [2] determines whether the chip capacitor passes based on whether the change in current per unit time measured by the current measuring unit satisfies a predetermined threshold value when the charging period is also within the measurable range of the current measuring unit.

[0105] [4]

[0106] The above judgment unit is,

[0107] During the insulation resistance measurement period, if the insulation resistance value calculated by the voltage measured by the voltage measuring unit and the current measured by the current measuring unit is below a predetermined threshold value, the chip capacitor is determined to be unsatisfactory.

[0108] During the above charging period, the chip capacitor is determined to be unsatisfactory by detecting a spike-shaped pulse wave of the current measured by the current measuring unit or the voltage measured by the voltage measuring unit.

[0109] [1] or [2] inspection device described.

[0110] [5]

[0111] A process for measuring the current during the charging period of a chip capacitor and the current during the insulation resistance measurement period after the charging period has elapsed, by means of a current measuring circuit, and

[0112] A process of measuring the voltage applied to the chip capacitor during the charging period and the insulation resistance measurement period by means of a voltage measuring circuit, and

[0113] A process for determining whether the chip capacitor passes or fails based on whether, by means of a determination circuit, the current measured by the current measuring circuit or the voltage measured by the voltage measuring circuit satisfies a predetermined threshold value during the charging period and the insulation resistance measurement period.

[0114] An inspection method equipped with

[0115] [6]

[0116] A process for measuring the current during the charging period of a chip capacitor and the current during the insulation resistance measurement period after the charging period has elapsed, by means of a current measuring circuit, and

[0117] A process of measuring the voltage applied to the chip capacitor during the charging period and the insulation resistance measurement period by means of a voltage measuring circuit, and

[0118] A process for determining whether the chip capacitor passes or fails based on whether, by means of a determination circuit, the current measured by the current measuring circuit or the voltage measured by the voltage measuring circuit satisfies a predetermined threshold value during the charging period and the insulation resistance measurement period.

[0119] A method for manufacturing a capacitor having

[0120] [7]

[0121] As a test program stored on a computer-executable memory medium,

[0122] By means of a current measuring circuit, the current during the charging period of the chip capacitor and the current during the insulation resistance measurement period after the charging period have elapsed are measured, and

[0123] The voltage applied to the chip capacitor during the charging period and the insulation resistance measurement period is measured by a voltage measurement circuit, and

[0124] A determination circuit that determines whether the chip capacitor passes the charge period and the insulation resistance measurement period, depending on whether the current measured by the current measurement circuit or the voltage measured by the voltage measurement circuit satisfies a predetermined threshold value.

[0125] A test program including functions. Explanation of the symbols

[0126] 1 : Electronic component sorting device 2 : Return part 3: Inspection device 11: Device body 12 : Supply unit 13 : Return section 14 : Inspection Department 15: Classification discharge section 16: Return container 21 (21a ~ 21h): receiving hole 31: Power supply 32: Measuring device 111 : Base section 112: Rotary drive device 113 : Control unit 121 : Hopper section 122 : Feeder 123 : Shooter 124 : Bucket 141 : Measurement terminal 142 : Measurement terminal 151 : Discharge path 311: Rectifier circuit 312: Filter Circuit 313: Constant Voltage Circuit 314: Constant Current Circuit 315: Output resistor 321: Current measuring section 322 : Differential waveform detector 323 : Voltage measuring section 324 : Control unit 325 : Judgment Division 326 : Memory 327 : Communications Department C: Chip capacitor I1: Current value I2: Limiting current P: Rotation axis P1 ~ P4 : Waveform R: Protection resistance SW1: Interlock relay SW2: Voltage Application Relay SW3: Polarity switching switch T0: Input terminal T1: First terminal T2: Second terminal Ta: Recharge period Ta1: Constant current charging period Ta2: Constant voltage charging period Ta21: Constant voltage current range exceedance period Ta22: Constant voltage current range non-excess period Tb: Insulation resistance measurement period V1: Set voltage

Claims

Claim 1 An inspection device comprising: a current measuring unit for measuring a current during a charging period of a chip capacitor and a current during an insulation resistance measurement period after the charging period has elapsed; a voltage measuring unit for measuring a voltage applied to the chip capacitor during the charging period and the insulation resistance measurement period; and a determination unit for determining whether the chip capacitor passes or fails based on whether the current measured by the current measuring unit or the voltage measured by the voltage measuring unit satisfies a predetermined threshold value during the charging period and the insulation resistance measurement period. Claim 2 In claim 1, the inspection device wherein the determination unit determines whether the chip capacitor passes based on the voltage measured by the voltage measuring unit when the current detected by the current measuring unit is outside the measurable range. Claim 3 An inspection device according to claim 1 or 2, wherein the determination unit determines whether the chip capacitor passes based on whether the amount of change per unit time of the current measured by the current measuring unit satisfies a predetermined threshold value when the charging period is also within the measurable range of the current measuring unit. Claim 4 An inspection device according to claim 1 or 2, wherein the judgment unit determines the chip capacitor as unsatisfactory when, during the insulation resistance measurement period, the insulation resistance value calculated by the voltage measured by the voltage measuring unit and the current measured by the current measuring unit is below a predetermined threshold value, and during the charging period, detects a spike-shaped pulse wave of the current measured by the current measuring unit or the voltage measured by the voltage measuring unit to determine the chip capacitor as unsatisfactory. Claim 5 An inspection method comprising: a process of measuring the current of a chip capacitor during a charging period and the current of an insulation resistance measurement period after the charging period elapses, by means of a current measuring circuit; a process of measuring the voltage applied to the chip capacitor during the charging period and the insulation resistance measurement period, by means of a voltage measuring circuit; and a process of determining whether the chip capacitor passes or fails, by means of a judgment circuit, based on whether the current measured by the current measuring circuit or the voltage measured by the voltage measuring circuit satisfies a predetermined threshold value during the charging period and the insulation resistance measurement period. Claim 6 A method for manufacturing a capacitor, comprising: a process of measuring a current during a charging period of a chip capacitor and a current during an insulation resistance measurement period after the charging period elapses, by means of a current measuring circuit; a process of measuring a voltage applied to the chip capacitor during the charging period and the insulation resistance measurement period by means of a voltage measuring circuit; and a process of determining whether the chip capacitor passes or fails, by means of a judgment circuit, based on whether the current measured by the current measuring circuit or the voltage measured by the voltage measuring circuit satisfies a predetermined threshold value during the charging period and the insulation resistance measurement period. Claim 7 A test program stored in a computer-executable memory medium, comprising the function of measuring the current of a chip capacitor during a charging period and the current during an insulation resistance measurement period after the charging period by means of a current measuring circuit, measuring the voltage applied to the chip capacitor during the charging period and the insulation resistance measurement period by means of a voltage measuring circuit, and determining whether the chip capacitor passes or fails by means of a judgment circuit, depending on whether the current measured by the current measuring circuit or the voltage measured by the voltage measuring circuit satisfies a predetermined threshold value during the charging period and the insulation resistance measurement period.

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