JP5953135B2 - Resistance measuring device and circuit board inspection device - Google Patents

Description

  The present invention relates to a resistance measurement device and a circuit board inspection device, and more specifically, relates to a technique that includes two resistance measurement units by a four-terminal method and simultaneously measures resistance values (electrical conductivity) of two measured objects. Is.

  In the resistance measurement method based on the four-terminal method, a DC power source and a voltmeter are used, and a predetermined DC constant current I is passed from the DC power source to the measured object via the current supply probe. The resulting voltage V is measured with a voltmeter via a voltage detection probe, and the resistance value R of the object to be measured is determined by division of V / I.

  According to the resistance measurement method based on this four-terminal method, particularly when the object to be measured has a low resistance, the resistance value R of the object to be measured can be further increased without being substantially affected by the contact resistance or wiring resistance of the probe. Although accurate measurement is possible, in many cases, a current supply line extending from the DC power supply to the current supply probe and a voltage detection line extending from the voltmeter to the voltage detection probe are wired adjacent to each other.

  For this reason, the magnetic flux generated around the current supply line due to energization is linked to the adjacent voltage detection line, so that an electromotive force is induced in the voltage detection line, which may cause a measurement error.

  In order to eliminate this point, the present applicant has previously proposed a resistance measuring apparatus shown in FIG. This resistance measuring device includes first and second resistance measuring units 10 and 20, and the resistance measuring units 10 and 20 simultaneously measure two measured objects Ra and Rb.

  The measured objects Ra and Rb are conductors made of a resistance element mounted on a circuit board or a copper foil or the like in a through hole formed in the circuit board. An inspection for the presence or absence of disconnection is performed based on the resistance value.

  Each of the first and second resistance measuring units 10 and 20 is based on a four-terminal method, and the first resistance measuring unit 10 includes a DC current source 11 and a voltmeter 12 as voltage detecting means, and similarly The second resistance measurement unit 20 includes a direct current source 21 and a voltmeter 22 as voltage detection means.

  In the example of FIG. 3, a pair of current supply probes 111 and 112 connected to the DC current source 11 of the first resistance measurement unit 10 via the lead wiring 110 are provided at both terminal portions of one measured object Ra, A pair of voltage detection probes 121 and 122 connected to the voltmeter 12 of the first resistance measurement unit 10 are brought into contact with each other through the lead wiring 120.

  Similarly, a pair of current supply probes 211 and 212 connected to the DC current source 21 of the second resistance measurement unit 20 via the routing wiring 210 and the routing wiring 220 are connected to both terminal portions of the other measured object Rb. A pair of voltage detection probes 221 and 222 connected to the voltmeter 22 of the second resistance measurement unit 20 are brought into contact with each other.

  In this case, the routing wirings 110 and 120 on the first resistance measurement unit 10 side and the routing wirings 210 and 220 on the second resistance measurement unit 20 side are arranged as close as possible, and the current value supplied from the DC current sources 11 and 21 is as follows. Are the same but reverse polarity.

  That is, the current flows through the routing wire 110 on the current supply side of the first resistance measurement unit 10 in the direction of the solid line in the figure, whereas the routing wiring 210 on the current supply side of the second resistance measurement unit 20 A current is passed in the direction indicated by the chain line arrow so that the direction is the same.

  As described above, the direct current (measurement) having the opposite polarity and the same current value with respect to the routing wiring 110 on the current supply side of the first resistance measurement unit 10 and the routing wiring 210 on the current supply side of the second resistance measurement unit 20. Since the magnetic flux generated due to the DC current is canceled by flowing the current (current) simultaneously, the electromotive force is not induced in the lead wires 120 and 220 on the voltage detection side, and the resistance value is measured more accurately. And the resistance values of two measured objects can be measured simultaneously.

JP 2010-2199 A

  However, there are the following problems when a large number (for example, several hundreds or more) of measured objects exist on the circuit board.

  When measuring each measured object Ra, Rb by moving each probe to the next two measured objects in a flying form, not only does it take time to transfer the probe, but also the routing wiring However, it is necessary to make the length longer, which is not preferable.

  Further, in the case of a fixture type in which each probe is implanted on a pin board for each object to be measured, the number of wires of each probe to the first resistance measuring unit 10 and the second resistance measuring unit 20 is extremely large. Not only does the wiring path become complicated, but it also takes a lot of work to connect these wirings. In addition, the stray capacitance increases as the wiring area increases. Furthermore, when the number of wirings increases, the number of changeover switches increases according to the number of wirings, resulting in increased component costs.

  Accordingly, an object of the present invention is to provide a resistance measuring device having first and second resistance measuring units by the four-terminal method, and among the many objects to be measured, the resistance values of two predetermined objects to be measured are sequentially provided. Is to facilitate the connection of the probe assigned to each object to be measured to each resistance measurement unit, and to shorten the length of the lead wiring so that the stray capacitance does not increase.

In order to solve the above-mentioned problems, the present invention provides a first resistance measuring unit having a first DC current source and first voltage measuring means, a second DC current source, and a second voltage. And a second resistance measuring unit having a measuring means, and simultaneously measuring the resistance values of the first and second measured objects adjacent to each other by the four-terminal method by each of the resistance measuring units. In
A pair of scanner boards, each of which is assigned to each of the two objects to be measured, and each of which is connected to four probes via routing wires,
The first main switch that is alternatively connected to one of the high potential electrodes Hp1 and Hp2 of the first and second voltage measuring means, and one of the high potential electrodes Hc1 and Hc2 of the first and second DC current sources. A second main switch that is alternatively connected to the first main switch, a third main switch that is alternatively connected to one of the low potential electrodes Lp1 and Lp2 of the first and second voltage measuring means, and the first and second A fourth main switch that is alternatively connected to one of the low potential electrodes Lc1 and Lc2 of the second DC current source;
First to fourth sub-switches for selectively connecting the four probes to any one of the common contacts of the first to fourth main switches, respectively.
Two probes out of the four probes on the one scanner board side are brought into contact with one terminal portion of the first measured object, and the remaining two probes are connected to one of the second measured objects. While making contact with the terminal portion, two probes out of the four probes on the other scanner board side are brought into contact with the other terminal portion of the first object to be measured, and the remaining two probes are connected with the first probe. 2 In contact with the other terminal part of the measurement object,
Each main switch and each sub-switch connects the four probes that are in contact with both terminal portions of the first device under test to the first resistance measurement unit, and both terminals of the second device under test. Four probes in contact with the part are connected to the second resistance measuring part, and a current is passed from the first DC current source to the first object to be measured from the one scanner board side, and the second A current flows from the second DC current source to the measured object from the other scanner board side, and a current direction flows through the first measured object, and a current direction flows through the second measured object. Is characterized by the reverse direction.

Specifically, as described in claim 2, the four probes on the one scanner board side are the first to fourth probes, and the four probes on the other scanner board side are the first probes. As the fifth to eighth probes, the first and second probes are brought into contact with one terminal portion of the first measured object, and the third and fourth probes are brought into contact with one terminal portion of the second measured object, With the first resistance measuring unit, the fifth and sixth probes are brought into contact with the other terminal portion of the first measured body, and the seventh and eighth probes are brought into contact with the other terminal portion of the second measured body. In performing simultaneously the resistance value measurement of the first object to be measured and the resistance value measurement of the second object to be measured by the second resistance measurement unit,
The first switch and the fifth probe are connected to the high potential electrode Hc1 and the low potential electrode Lc1 of the first DC current source, and the second and sixth probes are connected to the first voltage by the main switch and the sub switch. The third and seventh probes are connected to the high potential electrode Hc1 and the low potential electrode Lc1 of the second DC current source, and are connected to the high potential electrode Hp1 and the low potential electrode Lp1 of the measuring means. Are connected to the high potential electrode Hp1 and the low potential electrode Lp1 of the second voltage measuring means.

  Preferably, the routing wiring from the one scanner board to each probe is adjacently routed, and the routing wiring from the other scanner board to each probe is adjacent to each other. And wired.

  In measuring a large number of objects to be measured as a pair, as described in claim 4, a plurality of the pair of scanner boards are provided for the first resistance measurement unit and the second resistance measurement unit. Connected in parallel.

  Further, according to the present invention, as described in claim 5, the device under test is a resistance element disposed adjacent to a circuit board or a conductor in a through hole. A circuit board inspection apparatus that sequentially measures each of the resistance values of the plurality of objects to be measured by using the resistance value measuring apparatus according to any one of the above is also included.

  According to the present invention, the first resistance measurement is performed on the four probes that are in contact with both terminal portions of the first measured object by simply selectively switching the main switch and the sub switch provided on each scanner board. The four probes that are in contact with both terminals of the second object to be measured can be connected to the second resistance measuring part, and one scanner is connected to the first object to be measured from the first DC current source. A current is supplied from the board side, and a current is supplied from the second DC current source to the second measured object from the other scanner board side. The direction of the current flowing through the measurement body can be opposite.

  Also, the routing wiring of each probe only needs to be wired between the scanner board and the probe, the routing wiring can be shortened, and the routing wiring from one scanner board to each probe is routed adjacently, Similarly, it is possible to prevent an induced electromotive force from being generated in the lead wiring on the voltage detection side by routing the lead wiring from the other scanner board to each probe adjacent to each other.

The typical perspective view showing the embodiment of the resistance measuring device by the present invention. The schematic diagram which shows the structure of the scanner board used by this invention. The schematic diagram which shows the conventional resistance measuring apparatus provided with the two resistance measuring parts by a four terminal method.

  Next, an embodiment of the present invention will be described with reference to FIGS. 1 and 2, but the present invention is not limited to this.

  First, referring to FIG. 1, the resistance measurement apparatus according to this embodiment measures the resistance values of a plurality of measured objects Ra to Rn via a measurement board 100 and an IF board 200 as a relay board. Scanner boards 300 and 400 connected to the measurement board 100 are provided. The IF board 200 is an optional component, and the scanner boards 300 and 400 may be directly connected to the measurement board 100.

  Further, in this embodiment, the measured objects Ra to Rn are copper foils in the through holes formed in the circuit board, and when the resistance value is higher than a predetermined threshold value, It is determined that the through hole is disconnected by the control means that does not. The measured objects Ra to Rn may be resistance elements such as resistance chips mounted on a circuit board.

  In any case, in this embodiment, the measured objects Ra to Rn exist, for example, in units of several hundreds. However, in the following description, when it is not necessary to distinguish the measured objects Ra to Rn, As a general term, a measurement object RX is used.

  The measurement board 100 is provided with a first resistance measurement unit 101 and a second resistance measurement unit 102, both of which are based on the four-terminal method.

  The first resistance measuring unit 101 includes a DC constant current source CC1 and a voltmeter V1 as voltage measuring means. In the description here, the high potential pole of the DC constant current source CC1 is Hc1, its low potential pole is Lc1, the high potential pole of the voltmeter V1 is Hp1, and its low potential pole is Lp1.

  Similarly, the second resistance measuring unit 102 also includes a DC constant current source CC2 and a voltmeter V2 as a voltage measuring means, the high potential electrode of the DC constant current source CC2 is Hc2, its low potential electrode is Lc2, and the voltage. The high potential electrode of the total V1 is Hp2, and the low potential electrode is Lp2. For convenience of explanation, an electric circuit that communicates with the first resistance measurement unit 101 is referred to as line 1, and an electric circuit that communicates with the second resistance measurement unit 102 is referred to as line 2.

  The scanner boards 300 and 400 will be described. One scanner board 300 is a substrate having probes 301 to 304 that are in contact with one terminal side of the measured object RX, and the other scanner board 400 is the substrate of the measured object RX. It is a board | substrate which has the probes 401-404 which contact the other terminal part side.

  In this embodiment, since a plurality of scanner boards 300 and 400 are used, each of them is assumed to be a scanner board 300a to 300m and a scanner board 400a to 400m. The scanner board 300 (300a to 300m) and the scanner board 400 (400a to 400m) have the same configuration. Preferably, the scanner boards 300 and 400 have the same number.

  The scanner board 300 (300a to 300m) is housed in the upper scanner rack A, and the scanner board 400 (400a to 400m) is housed in the lower scanner rack B. One pair on the scanner rack B side is assigned to two measured objects RX as a pair. In other words, if there are 100 measured objects RX, for example, 50 scanner boards 300 and 400 are prepared.

  FIG. 1 illustrates a state where the scanner board 300a and the scanner board 400a make a pair and measure the resistance values of two adjacent measured objects Ra and Rb. This will be described with reference to FIG.

  The scanner board 300a includes first to fourth main switches 311 to 314 and first to fourth sub switches 321 to 324.

  The first main switch 311 has two switch elements 311a and 311b, and selects one of the high potential electrodes Hp1 and Hp2 of the first and second voltmeters V1 and V2. The second main switch 312 includes two switch elements 312a and 312b, and selects one of the high potential electrodes Hc1 and Hc2 of the first and second DC constant current sources CC1 and CC2.

  The third main switch 313 includes two switch elements 313a and 313b, and selects one of the low potential electrodes Lp1 and Lp2 of the first and second voltmeters V1 and V2. The fourth main switch 314 includes two switch elements 314a and 314b, and selects one of the low potential electrodes Lc1 and Lc2 of the first and second DC constant current sources CC1 and CC2.

  The first sub switch 321 includes four switch elements 321a to 321d, and connects the probe 301 to any one of the common contacts 311c to 314c of the main switches 311 to 314.

  The second sub switch 322 has four switch elements 322a to 322d, and connects the probe 302 to any one of the common contacts 311c to 314c of the main switches 311 to 314.

  The third sub switch 323 has four switch elements 323a to 323d, and connects the probe 303 to any one of the common contacts 311c to 314c of the main switches 311 to 314.

  The fourth sub switch 324 includes four switch elements 324a to 324d, and connects the probe 304 to any one of the common contacts 311c to 314c of the main switches 311 to 314.

  Similarly, the scanner board 400a also includes first to fourth main switches 411 to 414 and first to fourth sub switches 421 to 424.

  The first main switch 411 includes two switch elements 411a and 411b, and selects one of the high potential electrodes Hp1 and Hp2 of the first and second voltmeters V1 and V2. The second main switch 412 includes two switch elements 412a and 412b, and selects one of the high potential electrodes Hc1 and Hc2 of the first and second DC constant current sources CC1 and CC2.

  The third main switch 413 includes two switch elements 413a and 413b, and selects one of the low potential electrodes Lp1 and Lp2 of the first and second voltmeters V1 and V2. The fourth main switch 414 includes two switch elements 414a and 414b, and selects one of the low potential electrodes Lc1 and Lc2 of the first and second DC constant current sources CC1 and CC2.

  The first sub switch 421 includes four switch elements 421a to 421d, and connects the probe 404 to any one of the common contacts 411c to 414c of the main switches 411 to 414.

  The second sub switch 422 includes four switch elements 422a to 422d, and connects the probe 403 to any one of the common contacts 411c to 414c of the main switches 411 to 414.

  The third sub switch 423 includes four switch elements 423a to 423d, and connects the probe 402 to any one of the common contacts 411c to 414c of the main switches 411 to 414.

  The fourth sub switch 424 includes four switch elements 424a to 424d, and connects the probe 401 to any one of the common contacts 411c to 414c of the main switches 411 to 414.

  In measuring the resistance values of the two measured objects Ra and Rb, the two probes 301 and 302 of the four probes 301 to 304 on the scanner board 300a side are connected to one terminal portion RaT1 of the measured object Ra. The two probes 401 and 402 of the four probes 401 to 404 on the scanner board 400a side are brought into contact with the other terminal portion RaT2 of the measured object Ra.

  Further, the remaining two probes 303 and 304 on the scanner board 300a side are brought into contact with one terminal portion RbT1 of the measured object Rb, and the remaining two probes 403 and 404 on the scanner board 400a side are contacted with the measured object. The other terminal portion RbT2 of Rb is brought into contact.

  In this embodiment, of the probes 301, 302, 401, 402 that are in contact with both terminal portions RaT1, RaT2 of the measured object Ra, the probes 302, 401 are current supply probes, and the probes 301, 402 are voltage detection probes. To do.

  Of the probes 303, 304, 403, and 404 that are in contact with both terminal portions RbT1 and RbT2 of the measurement target Rb, the probes 304 and 403 are current supply probes, and the probes 303 and 404 are voltage detection probes.

  A DC constant current (measurement current) I1 is supplied from the scanner board 400a side to the measurement object Ra, and a DC constant current (measurement current) is supplied from the scanner board 300a side to the measurement object Rb. Let I2 flow. Note that the measurement currents I1 and I2 have the same current value (I1 = I2).

  Therefore, on the scanner board 300a side, the probe 301 is connected to the low potential electrode Lp2 of the second voltmeter V2 in the line 2 via the switch element 321b of the first sub switch 321 and the switch element 313b of the third main switch 313. .

  Further, the probe 302 is connected to the low potential electrode Lc2 of the second DC constant current source CC2 in the line 2 through the switch element 322a of the second sub switch 322 and the switch element 314b of the fourth main switch 314.

  Further, the probe 303 is connected to the high potential electrode Hp1 of the first voltmeter V1 in the line 1 through the switch element 323d of the third sub switch 323 and the switch element 311a of the first main switch 311.

  Further, the probe 304 is connected to the high potential electrode Hc1 of the first DC constant current source CC1 in the line 1 through the switch element 324c of the fourth sub switch 324 and the switch element 312a of the second main switch 312.

  On the other hand, on the scanner board 400a side, the probe 401 is connected to the high potential electrode Hc2 of the second DC constant current source CC2 in the line 2 via the switch element 424c of the fourth sub switch 424 and the switch element 412b of the second main switch 412. Connecting.

  Further, the probe 402 is connected to the high potential electrode Hp2 of the second voltmeter V2 in the line 2 via the switch element 423d of the third sub switch 423 and the switch element 411b of the first main switch 411.

  Further, the probe 403 is connected to the low potential electrode Lc1 of the first DC constant current source CC1 in the line 1 through the switch element 422a of the second sub switch 422 and the switch element 414a of the fourth main switch 414.

  Further, the probe 404 is connected to the low potential electrode Lp1 of the first voltmeter V1 in the line 1 through the switch element 421b of the first sub switch 421 and the switch element 413a of the third main switch 413.

  The switching between the main switch and the sub switch is performed by a control means (not shown). Moreover, although the electronic switch which consists of a semiconductor element etc. is used preferably as a main switch and a subswitch, the mechanical switch represented by the micro switch may be used.

  In this way, the measurement object Ra is connected to the line 2 of the second resistance measurement unit 102 and the measurement object Rb is connected to the line 1 of the first resistance measurement unit 101 by switching the scanner boards 300a and 400a. In addition, the flow direction of the measurement current I1 with respect to the measured object Ra is opposite to the flow direction of the measurement current I2 with respect to the measured object Rb.

  Accordingly, the routing wirings of the probes 301 and 302 and the routing wirings of the probes 303 and 304 are arranged in proximity, and the routing wirings of the probes 401 and 402 and the routing wirings of the probes 403 and 404 are arranged in proximity. Thus, it is possible to cancel the induced electromotive force generated by the application of the measurement current.

  Further, since the routing wiring only needs to be wired between the scanner board and the probe, the wiring length can be further reduced.

  The scanner boards 300a and 400a have been described above. Similarly, the scanner boards 300b and 400b; 300c, 400c... 300m and 400m are used as pairs, respectively, and are arranged adjacent to each other like the measured objects Ra and Rb. The resistance values of the two measured objects RX are measured simultaneously.

  Further, according to the circuit board inspection apparatus equipped with the resistance measuring apparatus, for example, whether there is a disconnection in the through hole of the circuit board having a large number of through holes (via holes), the influence of the induced electromotive force due to the energization of the measurement current Inspection can be performed quickly and more accurately without receiving the test.

100 measurement board 101 first resistance measurement unit (line 1)
102 2nd resistance measurement part (line 2)
300 (300a to 300m) One scanner board 400 (400a to 400m) The other scanner board 301 to 304, 401 to 404 Probes 311 to 314, 411 to 414 Main switches 321 to 324, 421 to 424 Sub switches V1, V2 Voltage Meter (voltage measuring means)
CC1, CC2 DC constant current source RX (Ra to Rn) Device to be measured RaT1, RaT2, RbT1, RbT2 Terminal section

Claims (5)

A first resistance measuring unit having a first DC current source and a first voltage measuring means; and a second resistance measuring unit having a second DC current source and a second voltage measuring means. In the resistance value measuring apparatus that simultaneously measures the resistance values of the first and second measured objects adjacent to each other by the method,
A pair of scanner boards, each of which is assigned to each of the two objects to be measured, and each of which is connected to four probes via routing wires,
The first main switch that is alternatively connected to one of the high potential electrodes Hp1 and Hp2 of the first and second voltage measuring means, and one of the high potential electrodes Hc1 and Hc2 of the first and second DC current sources. A second main switch that is alternatively connected to the first main switch, a third main switch that is alternatively connected to one of the low potential electrodes Lp1 and Lp2 of the first and second voltage measuring means, and the first and second A fourth main switch that is alternatively connected to one of the low potential electrodes Lc1 and Lc2 of the second DC current source;
First to fourth sub-switches for selectively connecting the four probes to any one of the common contacts of the first to fourth main switches, respectively.
Two probes out of the four probes on the one scanner board side are brought into contact with one terminal portion of the first measured object, and the remaining two probes are connected to one of the second measured objects. While making contact with the terminal portion, two probes out of the four probes on the other scanner board side are brought into contact with the other terminal portion of the first object to be measured, and the remaining two probes are connected with the first probe. 2 In contact with the other terminal part of the measurement object,
Each main switch and each sub-switch connects the four probes that are in contact with both terminal portions of the first device under test to the first resistance measurement unit, and both terminals of the second device under test. Four probes in contact with the part are connected to the second resistance measuring part, and a current is passed from the first DC current source to the first object to be measured from the one scanner board side, and the second A current flows from the second DC current source to the measured object from the other scanner board side, and a current direction flows through the first measured object, and a current direction flows through the second measured object. The resistance value measuring device is characterized in that the direction is reversed. The four probes on the one scanner board side are defined as first to fourth probes, and the four probes on the other scanner board side are defined as fifth to eighth probes. The first and second probes are brought into contact with the terminal portion, the third and fourth probes are brought into contact with one terminal portion of the second measured object, and the fifth and fifth probes are brought into contact with the other terminal portion of the first measured object. 6 probes are brought into contact with the other terminal portion of the second object to be measured, and the seventh and eighth probes are contacted to measure the resistance value of the first object to be measured by the first resistance measuring unit, and the second resistance. When simultaneously performing the resistance measurement of the second object to be measured by the measurement unit,
The first switch and the fifth probe are connected to the high potential electrode Hc1 and the low potential electrode Lc1 of the first DC current source, and the second and sixth probes are connected to the first voltage by the main switch and the sub switch. The third and seventh probes are connected to the high potential electrode Hc1 and the low potential electrode Lc1 of the second DC current source, and are connected to the high potential electrode Hp1 and the low potential electrode Lp1 of the measuring means. Is connected to the high potential electrode Hp1 and the low potential electrode Lp1 of the second voltage measuring means.   2. The routing wiring from the one scanner board to each probe is adjacently routed, and the routing wiring from the other scanner board to each probe is adjacently routed. Or the resistance value measuring apparatus of 2.   4. The resistance value according to claim 1, wherein a plurality of the pair of scanner boards are connected in parallel to the first resistance measurement unit and the second resistance measurement unit. 5. measuring device.   5. The resistance object measuring device according to claim 1, wherein the object to be measured is a resistance element disposed adjacent to a circuit board or a conductor in a through hole. A circuit board inspection apparatus characterized by measuring each resistance value of a pair of measuring bodies in sequence.

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