JP2015010880A - Insulation inspection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To correctly inspect an insulation state of an inspection target by preventing erroneous detection of a spark occurrence without being influenced by a capacitance value of a capacitance connected to an output terminal of a power source part.SOLUTION: An insulation inspection device includes: a power source part 4 for supplying an inspecting voltage V2 of a specified DC voltage value between a pair of conductor pattern groups PG by outputting a DC voltage V1 from an output terminal 4a to the pair of conductor pattern groups PG; a current detection part 6 for detecting a DC current I1 flowing between the pair of conductor pattern groups PG; a spark detection part 8 for detecting whether a spark is generated between the pair of conductor pattern groups PG; and a process part 9 for inspecting an insulation state of between the pair of conductor pattern groups PG on the basis of presence of detecting a spark by the spark detection part 8 and a resistance value Rm between the pair of conductor pattern groups PG. Further, the process part 9 applies control to the power source part 4 so as to lower a rate of increasing the DC voltage V1 until when the inspecting voltage V2 reaches the specified DC voltage value proportionately as a capacitance value C of the capacitance connected to the output terminal 4a.

Description

  The present invention relates to an insulation inspection apparatus that measures an insulation resistance value to be inspected and inspects an insulation state of the inspection object based on the insulation resistance value.

  As this type of insulation inspection apparatus, an insulation inspection apparatus disclosed in Japanese Patent No. 3546046 is known. This insulation inspection apparatus includes a variable voltage source, a voltmeter, a switch circuit connected to a wiring pattern on a circuit board, an ammeter, a control unit, a spark detection circuit, and the like. In this insulation inspection device, the insulation resistance value between the wiring patterns (inspection object) to which a predetermined DC voltage (test voltage) output from a variable voltage source is applied, is detected voltage value of voltmeter and detected current value of ammeter By calculating from the above and comparing with the threshold value, the quality of the insulation state between the wiring patterns is judged. When there is a wiring pattern with a poor insulation state, the circuit board is judged to be defective.

  Also, in this insulation inspection apparatus, when a discharge (spark) occurs between the wiring patterns due to the application of a DC voltage during the insulation inspection, the spark detection circuit detects the discharge and the insulation state of the wiring pattern is defective. It is determined that there is (that is, the circuit board is defective). In this case, since the output voltage (test voltage) of the variable voltage source suddenly drops when the spark occurs, the spark detection circuit detects the occurrence of the spark by detecting this voltage change.

Japanese Patent No. 3546046 (page 5-6, FIG. 1)

  However, the following problems exist in the conventional insulation inspection apparatus described above. That is, in this type of insulation inspection apparatus, normally, the switch circuit is simultaneously connected to a plurality of wiring patterns via a plurality of cables, and the wiring pattern for determining the insulation state among the plurality of wiring patterns is selectively variable. Connect to voltage source and ammeter. In this case, since each cable has a stray capacitance, the stray capacitance is connected to the output terminal of the variable voltage source via a switch circuit. In addition, since capacitances having capacitance values according to the distances and areas between each other are formed between the wiring patterns, this capacitance is also output via the switch circuit to the output terminal of the variable voltage source. It is connected to the. Thus, in this insulation inspection apparatus, when the total capacitance value of the capacitances connected to the output terminals in this way is large, when the variable voltage source starts outputting the test voltage, the capacitance is A phenomenon occurs in which a current for charging the battery flows in a short time (as a pulsed current having a large peak value) in a state where the current value is large. Therefore, in this insulation inspection device, a drop in the test voltage occurs due to this current flowing in a state where the current value is large, and the spark detection circuit erroneously detects this drop in the test voltage as the occurrence of a spark. There is a problem to be solved that erroneously determines that a circuit board is defective based on this.

  The present invention has been made to solve such a problem, and avoids erroneous detection of occurrence of a spark without being affected by the capacitance value of the capacitance connected to the output terminal of the power supply unit, and is an inspection object. It is a main object of the present invention to provide an insulation inspection apparatus capable of accurately inspecting the insulation state.

  In order to achieve the above object, the insulation inspection apparatus according to claim 1, wherein a power supply unit supplies a test voltage having a specified DC voltage value to the test object by outputting a DC voltage from an output terminal to the test object; A current detection unit that detects a direct current flowing through the inspection target when the inspection voltage is supplied; a spark detection unit that detects whether or not a spark has occurred in the inspection target when the inspection voltage is supplied; Based on the DC voltage value and the detected current value of the DC current, the resistance value of the inspection object is measured, and the inspection object is determined based on the measured resistance value and whether or not the spark is detected by the spark detection unit. A processing unit that performs an insulation inspection process for inspecting an insulation state of the first DC voltage, and the processing unit supplies a rate of increase of the DC voltage until the specified DC voltage value is reached to the output terminal. The current of the DC current that charges the capacitance at the start of the supply of the DC voltage by executing control for the power supply unit to reduce the capacitance value as the capacitance value of the continued capacitance increases. Suppresses the value below a predefined current threshold.

  According to a second aspect of the present invention, there is provided the insulation inspection apparatus according to the first aspect, wherein the plurality of probe pins are simultaneously brought into contact with the plurality of inspection points defined in the plurality of conductor patterns formed on the circuit board. Connecting a pair of conductor patterns selected as the inspection target from the plurality of conductor patterns to the output terminal of the power supply unit so that the inspection voltage can be supplied between the pair of conductor patterns; A switch unit that connects the current detection unit in the current path of the direct current, and the processing unit is electrostatically connected between the pair of conductor patterns selected as the inspection target and connected to the output terminal. The control of the rate of increase is performed on the power supply unit using the capacitance value of the capacitance as the capacitance value, and the pair of conductor patterns are obtained in the insulation inspection process. Measuring the resistance value between the groups as the resistance value.

  The insulation inspection apparatus according to claim 3, further comprising a capacitance measurement unit that measures the capacitance value of the capacitance connected to the output terminal in the insulation inspection device according to claim 2. Causes the capacitance measuring unit to measure the capacitance value each time the pair of conductor pattern groups is newly selected.

  The insulation inspection apparatus according to claim 4 is the insulation inspection apparatus according to claim 2, wherein each time the pair of conductor pattern groups is newly selected, the processing unit is brought into contact with the pair of conductor pattern groups. The number of probe pins being detected is detected, and the control for the rate of increase is performed on the power supply unit assuming that the capacitance value of the capacitance increases as the number of detected probe pins increases. To do.

  In the insulation inspection apparatus according to claim 1, control is performed to decrease the rate of increase of the DC voltage until the inspection voltage reaches a specified DC voltage value as the capacitance value of the capacitance connected to the output terminal increases. When the processing unit executes the power supply unit, the current value of the direct current flowing in a pulsed manner when charging the capacitance at the start of the supply of the DC voltage is suppressed to be less than a predetermined current threshold value. . Therefore, according to this insulation inspection apparatus, the presence or absence of a spark in the inspection object is avoided while avoiding a situation in which the spark detection unit erroneously detects that a spark has occurred in the inspection object based on the direct current flowing in a pulse shape. Can be accurately detected. Therefore, according to this insulation inspection apparatus, the processing unit can accurately inspect the insulation state of the inspection target based on the calculated resistance value of the inspection target and whether or not the spark detection unit detects the spark. .

  According to the insulation inspection apparatus of the second aspect, since the current value of the direct current flowing in a pulsed manner at the start of the supply of the direct current voltage can be suppressed to be less than the current threshold value, the spark detecting unit The presence or absence of a spark between the pair of conductor pattern groups is accurately avoided while avoiding erroneous detection that a spark has occurred between the pair of conductor pattern groups selected as an inspection object based on the direct current flowing through Can be detected. Therefore, according to this insulation inspection apparatus, the processing unit has a pair of conductor pattern groups to be inspected based on the calculated resistance value between the pair of conductor pattern groups and the presence or absence of the detection of the spark in the spark detection unit. It is possible to accurately inspect the insulation state between them.

  In the insulation inspection apparatus according to the third aspect, the capacitance measuring unit measures the capacitance value of the capacitance of the pair of conductor pattern groups actually connected to the output terminal of the power supply unit. Thereby, according to this insulation inspection apparatus, the processing unit is connected to the appropriate rate of increase of the DC voltage, that is, the output terminal, based on the capacitance value of the actual capacitance measured by the capacitance measuring unit. It is possible to calculate a rate of increase as high as possible within a range in which the current value of the pulsed direct current that flows when charging a certain electrostatic capacity can be reliably suppressed below the current threshold value. Therefore, according to this insulation inspection device, the inspection voltage is regulated to the specified DC voltage value while more reliably avoiding the occurrence of a situation in which the spark detection unit erroneously detects that a spark has occurred between the pair of conductor pattern groups. Thus, the time required for the insulation inspection can be shortened while more accurately inspecting the insulation state between the pair of conductor pattern groups.

  According to the insulation inspection apparatus of the fourth aspect, since it is possible to accurately detect the occurrence of a spark between the pair of conductor pattern groups in the spark detection unit, the processing unit can calculate between the calculated pair of conductor pattern groups. Based on the resistance value and the presence / absence of the occurrence of a spark detected by the spark detector, it is possible to accurately inspect the insulation state between the pair of conductor pattern groups to be inspected. Further, according to this insulation inspection apparatus, it is not necessary to measure the capacitance value of the capacitance for the pair of conductor pattern groups in advance or to measure the capacitance value by providing a capacitance measurement unit. It is possible to save the trouble of measuring the capacitance value and to avoid complication of the apparatus configuration.

1 is a configuration diagram showing a configuration of an insulation inspection device 1. 1 is a configuration diagram showing a configuration of a circuit board 100. FIG. It is explanatory drawing which shows the conductor pattern P which comprises each conductor pattern group PG. It is explanatory drawing which shows the capacitance value of each conductor pattern group PG.

  Hereinafter, embodiments of an insulation inspection apparatus will be described with reference to the accompanying drawings.

  First, the configuration of the insulation inspection apparatus 1 will be described.

  1 includes a substrate holding unit 2, a probe unit 3, a power supply unit 4, a voltage detection unit 5, a current detection unit 6, a switch unit 7, a spark detection unit 8, a processing unit 9, and an output unit 10. And a plurality of conductor patterns formed on the circuit board 100 held by the board holding part 2 (in this example, as an example, ten conductor patterns P1 to P10 as shown in FIG. The insulation state between the conductor pattern groups PG is inspected using a pair of conductor pattern groups PG each formed of a part of the pattern P) as an inspection target.

  The board holding unit 2 includes a fixture (not shown) and holds the circuit board 100 disposed on the surface at a predetermined position. The probe unit 3 includes a plurality of probe pins 11 and has a jig shape. In this case, each probe pin 11 corresponds to the number and position of inspection points TP1 to TP10 (also referred to as inspection points TP when not particularly distinguished) defined on the conductor patterns P1 to P10 of the circuit board 100, The probe unit 3 is erected on the surface facing the substrate holder 2. In addition, the probe unit 3 is moved toward and away from the substrate holding unit 2 by a moving mechanism (not shown) that operates according to the control of the processing unit 9, so that a plurality of probe pins 11 are inspected corresponding to the circuit board 100. Probing to contact the point TP is executed.

  Under the control of the processing unit 9, the power supply unit 4 generates the DC voltage V1 based on the reference potential (in this example, the ground potential) G and outputs it from the output terminal 4a. At this time, the power supply unit 4 has a rate of increase α (= dV / dt) set by the processing unit 9 and a target voltage value Vt set by the processing unit 9 (as an example, a direct current within a range of 50 V to 1000 V). The DC voltage V1 is increased until a desired DC voltage value selected from the voltage value is reached. In addition, the power supply unit 4 drops the DC voltage V1 from the target voltage value Vt to the reference potential according to the control of the processing unit 9, for example, at the same rate of decrease as the above increase rate α.

  The voltage detector 5 detects the DC voltage input between the pair of input terminals 5a and 5b and samples at a predetermined frequency to generate waveform data Dv indicating the voltage waveform of the detected DC voltage, Output to the processing unit 9. Specifically, as will be described later, the voltage detection unit 5 is configured such that one conductor pattern group PG of the pair of conductor pattern groups PG is connected to the input terminal 5a via the switch unit 7, and the other Conductive pattern group PG is connected to input terminal 5b. As a result, the voltage detection unit 5 detects the inspection voltage V2 supplied between the pair of conductor pattern groups PG via the switch unit 7 when the power supply unit 4 outputs the DC voltage V1. The waveform data Dv is output to the processing unit 9.

  The conductor pattern group PG is a set of conductor patterns P composed of one or more conductor patterns P selected as an inspection target from among the plurality of conductor patterns P. Is a set of two conductor pattern groups composed of different conductor patterns P selected in this way. In this example, as shown in FIG. 3, six conductor pattern groups PG1 to PG6 are defined. Further, as shown in FIG. 4, five sets of two conductor pattern groups as a pair of conductor pattern groups PG are defined, and two conductor pattern groups PG constituting the pair of conductor pattern groups PG are defined. The capacitance value C of the electrostatic capacitance is obtained in advance by, for example, an experiment, and is defined for each pair of conductor pattern groups PG.

  The capacitance value C of the electrostatic capacity for the two conductor pattern groups PG means that the two conductor pattern groups PG are selected as inspection targets, and an output terminal 4a of the power supply unit 4 and an input terminal of a current detection unit 6 described later. 6a, which is a capacitance value of the capacitance connected to the output terminal 4a of the power supply unit 4 when connected between the two conductor pattern groups PG in the circuit board 100. And a capacitance value of a stray capacitance formed between cables to be described later that connect each probe pin 11 of the probe unit 3 and the switch unit 7.

  The current detector 6 detects the direct current input between the pair of input terminals 6a and 6b and samples the DC current detected by sampling at a predetermined frequency (for example, the same frequency as the sampling frequency of the voltage detector 5). The waveform data Di indicating the current waveform is generated and output to the spark detection unit 8 and the processing unit 9. Specifically, one conductor pattern group PG of one pair of conductor pattern groups PG selected as an inspection target is connected to the output terminal 4a of the power supply unit 4 via the switch unit 7, and the other conductor pattern group PG is selected. The group PG is connected to the input terminal 6 a of the current detection unit 6 via the switch unit 7. Further, the input terminal 6 b of the current detection unit 6 is connected to the reference potential G.

  Thereby, the current detection unit 6 flows to the pair of conductor pattern groups PG as the inspection target when the DC voltage V1 is output by the power source unit 4 (when the inspection voltage V2 is supplied between the pair of conductor pattern groups PG). Current path of the direct current I1 (from the output terminal 4a of the power supply unit 4 to the switch unit 7, the probe unit 3, one conductor pattern group PG of the pair of conductor pattern groups PG, the other conductor pattern group PG, the probe unit 3 And a current path indicated by a broken line in FIG. 1 that reaches the reference potential G via the switch unit 7, detects the DC current I 1, and outputs the waveform data Di to the spark detection unit 8 and the processing unit 9. To do.

  In a normal ammeter including the current detection unit 6, the impedance between the pair of input terminals 6a and 6b is maintained at a low value. For this reason, the other conductor pattern group PG connected to the input terminal 6a of the current detection unit 6 via the switch unit 7 is almost defined as the reference potential G as the low-potential side conductor pattern group PG (that is, The conductor pattern P constituting the other conductor pattern group PG is defined to have the same low potential). On the other hand, one conductor pattern group PG connected to the output terminal 4a of the power supply unit 4 through the switch unit 7 is defined as a high-potential-side conductor pattern group PG substantially at the DC voltage V1 (that is, one of the conductor pattern groups PG). The conductor patterns P constituting the conductor pattern group PG are defined at the same high potential).

  The switch unit 7 includes a plurality of switches (not shown) and is configured as a scanner. The switch unit 7 is connected to the plurality of probe pins 11 via a cable (not shown), and also includes an output terminal 4a of the power supply unit 4, a pair of input terminals 5a and 5b of the voltage detection unit 5, and a current detection unit 6. The input terminal 6a is also connected via a cable (not shown). In addition, the switch unit 7 switches each switch to an on state or an off state according to the control of the processing unit 9, thereby causing a pair of conductor pattern groups PG to be inspected to be DC-connected between the pair of conductor pattern groups PG. The voltage detector V1 is connected to the power supply unit 4 so that the voltage V1 can be supplied, and the current detection unit 6 is connected to the current path of the direct current I1 output from the power supply unit 4.

  Specifically, the switch unit 7 controls the pair of conductor patterns PG selected from a plurality (five in this example) of a pair of conductor pattern groups PG shown in FIG. One conductor pattern group PG constituting the conductor pattern group PG is connected to the output terminal 4a of the power supply unit 4 via the probe pin 11 and the cable, and the other conductor pattern group PG is connected to the current via the probe pin 11 and the cable. Connected to the input terminal 6 a of the detection unit 6. The switch unit 7 connects the one conductor pattern group PG to the input terminal 5a of the voltage detection unit 5 through the probe pin 11 and the cable according to the control of the processing unit 9, and the other conductor pattern group PG. Is connected to the input terminal 5b of the voltage detector 5 via the probe pin 11 and the cable.

  The spark detector 8 detects whether or not a spark (discharge) has occurred between the pair of conductor pattern groups PG when the inspection voltage V2 is supplied between the pair of conductor pattern groups PG selected as the inspection target. In addition, when the occurrence of a spark is detected, a detection signal S1 is output to the processing unit 9. In this example, as an example, the spark detection unit 8 compares the current value of the direct current I1 represented by the waveform data Di output from the current detection unit 6 with a predetermined current threshold Ith, When the current value of the direct current I1 becomes equal to or greater than the current threshold value Ith, it is determined that a spark has occurred, and the detection signal S1 is output for a predetermined time.

  When a spark (discharge) occurs between the pair of conductor pattern groups PG when the inspection voltage V2 is supplied between the pair of conductor pattern groups PG, the current value is equal to or greater than the current threshold value Vthi as described above. Since the direct current I1 flows in a short time, the voltage waveform of the DC voltage V1 output from the power supply unit 4 temporarily falls due to this, and accordingly, the voltage waveform of the inspection voltage V2 also appears. A temporary fall occurs. Therefore, the spark detection unit 8 receives the waveform data Dv instead of the waveform data Di, and compares the latest waveform data Dv with the waveform data Dv immediately before the latest waveform data Dv. It is also possible to adopt a configuration that outputs a detection signal S1 when a spark is generated when it is detected that the voltage has greatly decreased.

  The processing unit 9 includes a CPU and a memory (both not shown) as an example, and executes control on the above-described moving mechanism (not shown), the power supply unit 4 and the switch unit 7. Further, the processing unit 9 is based on the waveform data Dv output from the voltage detection unit 5, the waveform data Di output from the current detection unit 6, and the presence / absence of output of the detection signal S <b> 1 from the spark detection unit 8. An insulation inspection process for inspecting the insulation state between the pair of conductor pattern groups PG is executed. In addition, the processing unit 9 executes an output process for outputting the result of the insulation inspection process to the output unit 10.

  Further, the memory of the processing unit 9 includes information on the conductor pattern group PG shown in FIG. 3, information on the pair of conductor pattern groups PG shown in FIG. 4, a current threshold Ith, and a resistance threshold. A value Rth is stored in advance.

  The output unit 10 is configured by a display device such as an LCD as an example, and displays the result of the insulation inspection process executed by the processing unit 9.

  Next, the operation of the insulation inspection apparatus 1 will be described with reference to the drawings. It is assumed that the circuit board 100 is previously placed on the board holding unit 2 in a state of being held by the fixture.

  First, the processing unit 9 controls the moving mechanism to move the probe unit 3 in the direction of the circuit board 100, so that the tip end of each probe pin 11 of the probe unit 3 corresponds to the corresponding inspection on each conductor pattern P1 to P10. Contact (probing) the point TP.

  Next, the processing unit 9 performs an insulation inspection process for a plurality of pairs of conductor pattern groups PG shown in FIG. In this insulation inspection process, the processing unit 9 performs processing for one pair of conductor pattern groups PG selected as the first inspection target from among a plurality of pairs of conductor pattern groups PG stored in the memory as shown in FIG. (Information on the two conductor pattern groups PG constituting the pair of conductor pattern groups PG and the capacitance value C for the pair of conductor pattern groups PG) are read out. In this example, as an example, a pair of conductor pattern groups PG are to be inspected in the order of numbers shown in FIG. Thereby, the processing unit 9 firstly has information on the two conductor pattern groups PG constituting the pair of conductor pattern groups PG (information specifying the conductor pattern groups PG1, PG2), and the pair of conductor pattern groups PG1, PG2. The capacitance value C1 is read out.

  Subsequently, the processing unit 9 converts the conductor patterns (constituting conductor patterns) P constituting the two conductor pattern groups PG constituting the pair of conductor pattern groups PG to be inspected into the conductor pattern group PG shown in FIG. Identify by referring to the information. In this case, since the two conductor pattern groups PG are the conductor pattern groups PG1 and PG2, the processing unit 9 refers to FIG. 3 so that one conductor pattern group PG1 is constituted by the conductor pattern P1, and the other It is specified that the conductor pattern group PG2 is composed of the conductor pattern P2.

  Next, the processing unit 9 executes control on the switch unit 7 to thereby perform one conductor pattern group PG (each conductor pattern constituting one conductor pattern group PG) of the pair of conductor pattern groups PG to be inspected. P) is connected to the output terminal 4 a of the power supply unit 4 and to the input terminal 5 a of the voltage detection unit 5. In addition, the processing unit 9 executes control on the switch unit 7 to change the other conductor pattern group PG (each conductor pattern P constituting the other conductor pattern group PG) of the pair of conductor pattern groups PG. In addition to being connected to the input terminal 6 a of the current detector 6, it is connected to the input terminal 5 b of the voltage detector 5. In this example, since the two conductor pattern groups PG are the conductor pattern groups PG1 and PG2, the conductor pattern P1 constituting one conductor pattern group PG (for example, the conductor pattern group PG1) is connected to the output terminal of the power supply unit 4. 4a and the input terminal 5a of the voltage detector 5, and the conductor pattern P2 constituting the other conductor pattern group PG (for example, conductor pattern group PG2) is connected to the input terminal 6a of the current detector 6 and the voltage detector 5 To the input terminal 5b.

  Subsequently, the processing unit 9 is based on the capacitance value C1 of the pair of conductor pattern groups PG1 and PG2 to be inspected read from the memory and the current threshold value Ith stored in the memory. The rate of increase α of the DC voltage V1 to be output from is calculated.

  Specifically, when the power supply unit 4 starts to output the DC voltage V1, the voltage value of the DC voltage V1 is the capacitance of the conductor pattern groups PG1 and PG2 connected to the output terminal 4a of the power supply unit 4. However, the DC current I1 flowing during the charging becomes a pulsed current, and the peak current value I1p of the DC current I1 is about the pair of conductor pattern groups PG1 and PG2 to be inspected. When the capacitance value of the capacitance is C, it is expressed by the formula I1p = C × α. Based on the peak current value I1p, the processing unit 9 calculates an increase rate α at which the peak current value I1p of the direct current I1 during charging is less than the current threshold value Ith. In this case, since the capacitance value of the capacitance for the pair of conductor pattern groups PG1 and PG2 as the first inspection target is C1, the processing unit 9 calculates the increase rate α based on the capacitance value C1.

  When the rate of increase α is small, the time until the DC voltage V1 reaches the target voltage value Vt becomes longer, and the time required for the insulation test becomes longer. For this reason, it is preferable to increase the increase rate α as much as possible within a range where the peak current value I1p of the direct current I1 during charging does not exceed the current threshold value Ith.

  Next, the processing unit 9 starts the output of the DC voltage V1 at the calculated rate of increase α to the power supply unit 4 to increase the DC voltage V1 to the target voltage value Vt (the inspection voltage V2 is set to a specified value). Increase to DC voltage). Thus, from the output terminal 4a of the power supply unit 4, the switch unit 7, the probe unit 3, the probe pin 11, one conductor pattern group PG1 of the pair of conductor pattern groups PG, the other conductor pattern group PG2, and the probe pin 11 The DC current I1 flows in the current path that reaches the reference potential G via the probe unit 3, the switch unit 7, and the current detection unit 6. The current detector 6 detects the direct current I1 and outputs the waveform data Di to the spark detector 8 and the processor 9.

  In the state where the DC voltage V1 has reached the target voltage value Vt (the current value of the DC current I1 is usually extremely small, the inspection voltage V2 has reached a specified DC voltage value substantially equal to the target voltage value Vt). The unit 9 acquires the waveform data Dv output from the voltage detection unit 5 and the waveform data Di output from the current detection unit 6, and based on the waveform data Dv, a pair of conductor pattern groups PG1, PG2 A voltage value of the inspection voltage V2 supplied therebetween is calculated, and a current value of the direct current I1 flowing between the pair of conductor pattern groups PG1 and PG2 is calculated based on the waveform data Di. Further, the processing unit 9 generates a pair of conductor patterns based on the specified DC voltage value (voltage value when the DC voltage V1 is the target voltage value Vt) of the calculated inspection voltage V2 and the current value of the DC current I1. The resistance value Rm between the groups PG1 and PG2 (in this case, the insulation resistance value) Rm is calculated, and compared with the resistance threshold value Rth stored in the memory, the calculated resistance value Rm is equal to or greater than the resistance threshold value Rth. In this case, it is determined that there is a high possibility that the insulation state between the pair of conductor pattern groups PG1 and PG2 is good. When the calculated resistance value Rm is less than the resistance threshold value Rth, the pair of conductor pattern groups PG1 and PG2 It is determined that the insulation state between them is defective. In addition, when the calculation of the resistance value Rm is completed, the processing unit 9 executes control on the power supply unit 4 to reduce the voltage value of the DC voltage V1 from the target voltage value Vt to zero volts.

  The processing unit 9 outputs the detection signal S1 from the spark detection unit 8 immediately after the start of the output of the DC voltage V1 by the power supply unit 4 until the determination of the insulation state based on the resistance value Rm is completed. By detecting whether or not the output of the detection signal S1 is detected, it is detected that a spark has occurred between the pair of conductor pattern groups PG1 and PG2, and when the output of the detection signal S1 is not detected, It is detected that no spark has occurred between the conductor pattern groups PG1 and PG2.

  In this case, due to the application of the inspection voltage V2 between the pair of conductor pattern groups PG1 and PG2, the pair of conductor pattern groups in the middle of the increase of the inspection voltage V2 and in a state where the specified DC voltage value is reached. There may be a problem that the insulation state between PG1 and PG2 changes temporarily. For example, when a whisker-like pattern extending from one to the other of the pair of conductor pattern groups PG1 and PG2 is present on the circuit board 100, in the middle of the increase of the inspection voltage V2 and in a state where the specified DC voltage value is reached, When the voltage between the pair of conductor pattern groups PG1 and PG2 reaches a constant voltage, a spark is generated between the pair of conductor pattern groups PG1 and PG2 via the whisker-like pattern. Since the whisker-like pattern burns out due to the occurrence of this spark, the resistance value Rm between the pair of conductor pattern groups PG1 and PG2 thereafter may be equal to or greater than the resistance threshold value Rth. 100 is damaged. Therefore, when detecting the output of the detection signal S1 (that is, when a spark is generated), the processing unit 9 determines that the insulation state between the pair of conductor pattern groups PG1 and PG2 is defective.

  The spark detection unit 8 detects the occurrence of spark by comparing the current value of the direct current I1 represented by the waveform data Di and the current threshold value Ith, but a pair of conductor pattern groups The peak current value I1p of the direct current I1 that flows during charging of the capacitance (capacitance value C1) between PG1 and PG2 is the increase rate that the increase rate α of the DC voltage V1 is calculated as described above. It is suppressed below the threshold value Ith. As a result, during this charging (until the DC voltage V1 reaches the target voltage value Vt), the pair of conductor pattern groups PG1, PG2 based on the waveform data Di of the DC current I1 in which the spark detector 8 flows in a pulsed manner. Occurrence of an accidental detection that a spark has occurred in the meantime is avoided. Accordingly, the processing unit 9 can accurately detect whether or not a spark has occurred between the pair of conductor pattern groups PG1 and PG2 based on the presence or absence of the detection signal S1 from the spark detection unit 8. Yes.

  Subsequently, the processing unit 9 is based on the above determination result based on the resistance value Rm and the above determination result based on the presence or absence of occurrence of sparks for the insulation state between the pair of conductor pattern groups PG1 and PG2. When the calculated resistance value Rm is greater than or equal to the resistance threshold value Rth and when it is determined that no spark has occurred between the pair of conductor pattern groups PG1 and PG2, the distance between the pair of conductor pattern groups PG1 and PG2 It is determined that the insulation state is good. On the other hand, when the processing unit 9 detects that the calculated resistance value Rm is less than the resistance threshold value Rth or that a spark has occurred between the pair of conductor pattern groups PG1 and PG2, the pair of conductor pattern groups PG1. , PG2 is determined to be defective. The processing unit 9 stores the determination result in the memory in association with the pair of conductor pattern groups PG1 and PG2. Thereby, the insulation inspection process between one pair of conductor pattern groups PG1 and PG2 is completed.

  Thereafter, the processing unit 9 converts the remaining pair of conductor pattern groups PG of the pair of conductor pattern groups PG shown in FIG. 4 into a pair of conductor pattern groups PG2, PG3, a pair of conductor pattern groups PG2, PG4,. In this manner, while sequentially selecting as inspection targets, each conductor pattern P of the selected pair of conductor pattern groups PG is specified with reference to FIG. 3, and one conductor pattern of the pair of conductor pattern groups PG is specified. Each conductor pattern P constituting the group PG is connected to the output terminal 4a of the power supply unit 4 and the input terminal 5a of the voltage detection unit 5 and each conductor pattern P constituting the other conductor pattern group PG is connected to the current detection unit 6. A pair of test objects connected to the input terminal 6a and the input terminal 5b of the voltage detection unit 5 in the same manner as when the pair of conductor pattern groups PG1 and PG2 is set as the test target. Executing the insulation test process for the conductive pattern group PG.

  In this case, each time the processing unit 9 newly selects a pair of conductor pattern groups PG to be inspected, based on the capacitance value C2 (C3, C4, C5) for the pair of conductor pattern groups PG to be inspected. And calculating the rate of increase α of the DC voltage V1 when charging the capacitance between the pair of conductor pattern groups PG (increasing the DC voltage V1 from zero volts to the target voltage value Vt) as described above, The DC voltage V1 is increased with respect to the portion 4 at the increase rate α. Thus, the increase rate α of the DC voltage V1 is controlled by the processing unit 9 so as to decrease as the capacitance value C of the capacitance for the pair of conductor pattern groups PG increases.

  As described above, when the insulation inspection process for all the pair of conductor pattern groups PG shown in FIG. 4 is completed, the processing unit 9 executes the output process to insulate each pair of conductor pattern groups PG. The state inspection result (insulation inspection processing result) is output to the output unit 10. Thereby, the inspection of the circuit board 100 is completed.

  In this insulation inspection apparatus 1, as described above, the processing unit 9 sets the capacitance value C of the capacitance for the pair of conductor pattern groups PG selected as the inspection target and connected to the output terminal 4 a of the power supply unit 4. Based on this, as the capacitance value C increases, the power supply unit 4 is controlled to decrease the rate of increase α of the DC voltage V1.

  Therefore, according to the insulation inspection apparatus 1, the DC voltage V1 is increased from zero volts until the target voltage value Vt is reached, and the inspection voltage V2 is increased to a specified DC voltage value (between a pair of conductor pattern groups PG). When charging the electrostatic capacity), it is possible to reliably prevent the current value of the direct current I1 flowing in a pulsed manner from the pair of conductor pattern groups PG from exceeding the current threshold value Ith. . As a result, the spark detection unit 8 that detects the presence or absence of a spark between the pair of conductor pattern groups PG based on the current value of the DC current I1 and the current threshold value Ith generates the pulsed DC current I1. The detection signal S1 is output by accurately detecting the presence / absence of a spark between the pair of conductor pattern groups PG while avoiding an erroneous detection that a spark has occurred between the pair of conductor pattern groups PG. Can do. Therefore, according to the insulation inspection apparatus 1, the processing unit 9 performs a pair of conductor pattern groups PG to be inspected based on the calculated resistance value Rm between the pair of conductor pattern groups PG and the presence / absence of the detection signal S1. It is possible to accurately inspect the insulation state between them.

  In the insulation inspection apparatus 1, the capacitance value C of the capacitance between the pair of conductor pattern groups PG to be inspected is obtained in advance by experiments or the like, and as shown in FIG. A configuration in which the data is stored in the memory in correspondence is adopted, but as shown by a broken line in FIG. 1, a capacitance measuring unit 21 that measures the capacitance between the output terminal 4 a of the power supply unit 4 and the reference potential G is provided. Each time a pair of conductor pattern groups PG are newly selected and connected to the output terminal 4a of the power supply unit 4 (a pair of conductor pattern groups PG to be inspected is changed), a new one is added to the output terminal 4a. A configuration in which the capacitance value C of the capacitance between the pair of connected conductor pattern groups PG is measured and output to the processing unit 9 may be employed.

  In the insulation inspection apparatus adopting this configuration, the processing unit 9 is based on the capacitance value C of the capacitance of the pair of conductor pattern groups PG actually connected to the output terminal 4a of the power supply unit 4, and the DC voltage V1. In the range in which the current value of the pulsed direct current I1 that flows when charging the capacitance connected to the output terminal 4a can be reliably suppressed below the current threshold Ith. It is possible to calculate an increase rate α that is as high as possible. Therefore, according to this insulation inspection apparatus, the DC voltage V1 is set to the target voltage value while more reliably avoiding the occurrence of a situation in which the spark detection unit 8 erroneously detects that a spark has occurred between the pair of conductor pattern groups PG. Since Vt (as a result, the inspection voltage V2 can be increased to a prescribed DC voltage value) in a shorter time, it is necessary for the insulation inspection while more accurately inspecting the insulation state between the pair of conductor pattern groups PG. Time can be shortened.

  Further, the capacitance value C of the capacitance for the pair of conductor pattern groups PG is equal to the capacitance value of the capacitance formed between the two conductor pattern groups PG in the circuit board 100 and the probe unit 3 as described above. The total capacitance value of the stray capacitance formed between the cables connecting the probe pins 11 and the switch unit 7. Further, when the pair of conductor pattern groups PG selected as the inspection target is changed, the capacitance value of the stray capacitance does not change so much, whereas the capacitance value C of the capacitance of the pair of conductor pattern groups PG is a pair. As the number of conductor patterns P constituting the conductor pattern group PG increases, the number tends to increase. For this reason, the capacitance value C of the capacitance for the pair of conductor pattern groups PG increases as the number of conductor patterns P constituting the pair of conductor pattern groups PG increases. Further, when the number of conductor patterns P constituting a pair of conductor pattern groups PG increases, the number of probe pins 11 brought into contact with the conductor patterns P increases as the number of conductor patterns P increases.

  Thereby, instead of the configuration in which the rate of increase α of the DC voltage V1 is controlled based on the capacitance value C of the capacitance for the pair of conductor pattern groups PG described above, the conductor pattern P that configures the pair of conductor pattern groups PG. (Ie, the number of probe pins 11 brought into contact with the conductor pattern P constituting the pair of conductor pattern groups PG), the power supply unit 4 controls the power supply unit 4 to reduce the increase rate α as the number (number) increases. It is also possible to adopt a configuration that executes the above.

  According to the insulation inspection apparatus adopting this configuration, as compared with the above two embodiments, the processing unit 9 cannot acquire the accurate capacitance value C of the capacitance of the pair of conductor pattern groups PG. Since the increase rate α is set low with a margin, the time required to raise the DC voltage V1 to the target voltage value Vt is slightly longer, and as a result, the time required for the insulation test is also slightly longer. However, also in this insulation inspection apparatus, since the spark detection unit 8 can accurately detect the occurrence of a spark between the pair of conductor pattern groups PG, similarly to the above two embodiments, the processing unit 9 can accurately inspect the insulation state between the pair of conductor pattern groups PG to be inspected based on the calculated resistance value Rm between the pair of conductor pattern groups PG and the presence or absence of the detection signal S1. Further, according to this insulation inspection apparatus, it is not necessary to measure the capacitance value C of the capacitance for the pair of conductor pattern groups PG in advance or to measure the capacitance value C by providing the capacitance measuring unit 21. Thus, it is possible to save the trouble of measuring the capacitance value C by experiment or the like, or to avoid complication of the apparatus configuration.

  In the above example, a configuration in which the spark detection unit 8 is disposed separately from the processing unit 9 is employed, but a configuration in which the processing unit 9 also functions as the spark detection unit 8 can be employed. In the above example, the voltage detector 5 is used to detect the inspection voltage V2 that is actually supplied between the pair of conductor pattern groups PG to be inspected, and the resistance value is determined using the inspection voltage V2. Although a preferred configuration for calculating Rm is adopted, since the inspection voltage V2 is substantially equal to the DC voltage V1 output from the power supply unit 4, a simple configuration is used in which the resistance value Rm is calculated using the DC voltage V1. You can also In the above example, the conductor pattern P formed on the circuit board 100 is an inspection target. However, the inspection target is not limited to this, and the conductor portion of the electrical device can be the inspection target. Of course.

DESCRIPTION OF SYMBOLS 1 Insulation inspection apparatus 4 Power supply part 4a Output terminal 6 Current detection part 7 Switch part 8 Spark detection part 9 Processing part 11 Probe pin 21 Capacitance measurement part I1 DC current P Conductor pattern PG Conductor pattern group S1 Detection signal V1 DC voltage Vt Target voltage Value α rate of increase

Claims (4)

A power supply unit that supplies an inspection voltage having a specified DC voltage value to the inspection object by outputting a DC voltage from the output terminal to the inspection object, and detects a direct current that flows through the inspection object when the inspection voltage is supplied Based on a current detection unit, a spark detection unit that detects whether or not a spark has occurred in the inspection target when the inspection voltage is supplied, and the specified DC voltage value and the detected current value of the DC current A processing unit that measures the resistance value of the inspection object and performs an insulation inspection process that inspects the insulation state of the inspection object based on the measured resistance value and the presence or absence of detection of the spark by the spark detection unit; Prepared,
The processing unit controls the power supply unit to reduce the rate of increase of the DC voltage until the specified DC voltage value is reached as the capacitance value of the capacitance connected to the output terminal increases. An insulation inspection apparatus that suppresses the current value of the DC current that charges the capacitance at a start of supply of the DC voltage to less than a predetermined current threshold value when executed. A plurality of probe pins that are simultaneously brought into contact with a plurality of inspection points defined in a plurality of conductor patterns formed on the circuit board;
A pair of conductor pattern groups selected as the inspection target from among the plurality of conductor patterns are connected to the output terminal of the power supply unit so that the inspection voltage can be supplied between the pair of conductor pattern groups, and A switch unit for connecting the current detection unit in the current path of the direct current,
The processing unit controls the power supply unit to control the increase rate with the capacitance value of the capacitance between the pair of conductor pattern groups selected as the inspection target and connected to the output terminal as the capacitance value. The insulation inspection apparatus according to claim 1, wherein the insulation inspection apparatus performs the insulation inspection process and measures a resistance value between the pair of conductor pattern groups as the resistance value in the insulation inspection process. A capacitance measuring unit for measuring the capacitance value of the capacitance connected to the output terminal;
The insulation inspection apparatus according to claim 2, wherein the processing unit causes the capacitance measuring unit to measure the capacitance value each time the pair of conductor pattern groups is newly selected.   The processing unit detects the number of the probe pins that are in contact with the pair of conductor pattern groups each time the pair of conductor pattern groups is newly selected, and as the detected number increases, The insulation inspection apparatus according to claim 2, wherein the control for the rate of increase is performed on the power supply unit on the assumption that the capacitance value of the capacitance is large.

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