JP2016033511A - Printed board inspection device and inspection method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a printed board inspection device and inspection method capable of surely detecting a signal for accurate inspection in a state where a probe for detecting an electric signal directly contacts with a conductor pattern.SOLUTION: An electric inspection device of a printed board applies an electric signal to a conductor pattern formed on the printed board, and inspects the quality of the conductor pattern. The electric inspection device includes: a first probe contacting with one end of the conductor pattern; a second probe arranged at the other end of the conductor pattern through an insulator; a constant current source; a first connection device for connecting the first probe to the constant current source; a second connection device for changing the electrical connection state of the second probe with respect to the reference potential of the constant current source; and a measurement circuit for measuring the potential of the first probe with respect to the reference potential of the constant current source.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an apparatus for inspecting an electrical state of a conductor pattern of a printed board and an inspection method thereof.

  When inspecting an electrical state such as a breakage of a conductor pattern on a printed circuit board, in general, a continuity test is performed by bringing an inspection probe into contact with both ends of the conductor pattern, but one end of the conductor pattern is covered with an insulating film. In some cases, such as when formed on a touch panel or the like, the inspection probe may not be in direct contact with the conductor pattern. In such a case, as disclosed in Patent Document 1 and Patent Document 2, the inspection probe is inspected in a non-contact state with respect to the conductor pattern.

In Patent Document 1, in a board inspection applied to a flexible printed circuit board or the like, a probe is individually contacted with one inspection target electrode group of a conductor pattern and is not in contact with the other inspection target electrode group of the conductor pattern. It is disclosed that sensors are arranged close to each other, and a weak electromagnetic field (or electromagnetic wave) is captured with respect to the inspection target electrode by the non-contact sensor to determine whether or not each conductor pattern is disconnected.
In Patent Document 2, a probe is electrically connected to each of a plurality of conductor patterns on a printed circuit board, and a sensor for detecting an inspection signal is capacitively coupled to the plurality of conductor patterns in a non-contact manner. It is disclosed that an electrical signal having an abrupt change is sequentially input to determine a conductive state of a conductor pattern based on a maximum value of a transient current flowing through a sensor.

Japanese Patent No. 2994259 Japanese Patent No. 3361311

However, in any of the methods described in the patent documents, there is a possibility that the signal cannot be reliably detected because the probe for detecting the electric signal is arranged in non-contact with the conductor pattern and is not in direct contact with the conductor pattern. There is.

  The present invention has been made in view of such circumstances, and in a state where a probe for detecting an electric signal is in direct contact with a conductor pattern, a signal can be reliably detected, and a printed circuit board inspection can be performed accurately. An apparatus and an inspection method are provided.

  The printed circuit board inspection apparatus of the present invention is in contact with one end of the conductor pattern in an electrical inspection apparatus for a printed circuit board that applies an electrical signal to a conductor pattern formed on the printed circuit board and inspects the quality of the conductor pattern. A first probe, a second probe disposed on the other end of the conductor pattern via an insulator, a constant current source, and a first connection device for connecting the first probe to the constant current source; A second connection device for changing an electrical connection state of the second probe with respect to a reference potential of the constant current source; and a measurement circuit for measuring a potential of the first probe with respect to a reference potential of the constant current source; Is provided.

In the printed circuit board inspection method of the present invention, the first probe is directly brought into contact with one end of the conductor pattern, the second probe is disposed on the other end of the conductor pattern via an insulator, and at time T1, the first probe is arranged. The flow of current from the constant current source to the probe is started, and the electrical connection state of the second probe with respect to the reference potential of the constant current source is changed at time T2 when a predetermined time t12 has elapsed from time T1, and the change The quality of the conductor pattern is determined from the measurement result of the potential of the first probe with respect to the reference potential of the constant current source at the time.
In this printed circuit board inspection method, when the amount of potential displacement at one end of the conductor pattern per predetermined unit time tu changes when the electrical connection state of the second probe with respect to the reference potential of the constant current source changes. It can be determined that the conductor pattern is a good product.

In the present invention, the first probe is brought into contact with one end of the conductor pattern, the second probe is arranged on the other end of the conductor pattern via an insulator, and the electrical connection state on the second probe side is changed, The potential of the first probe is measured. That is, since the electrical signal of the first probe in contact with the conductor pattern is detected, the electrical signal can be reliably detected, and an accurate substrate inspection can be performed.
In this case, if the other end of the conductor pattern is exposed on the surface of the printed circuit board, the insulator disposed on the other end of the printed circuit board conductor pattern is appropriately prepared on the other end of the conductor pattern. However, when the other end of the conductor pattern is covered with an insulating film, the insulating film can be an insulator, and the second probe may be disposed on the insulating film.
The second connection device can change the connection state of the second probe by connecting or blocking the second probe with respect to the reference potential of the constant current source.
Further, both the first probe and the second probe may be disposed on one surface side of the printed circuit board, and may be disposed on the opposite surfaces of the printed circuit board.

In the printed circuit board inspection apparatus according to the present invention, a predetermined static electricity is provided between the second probe and the second connection device, or between the second probe and the reference potential of the constant current source, or both. A capacitor having a capacitance is preferably connected.
Due to the presence of the capacitor, the amount of potential displacement on the first probe side can be increased, and a more accurate inspection can be performed.

The printed circuit board inspection apparatus according to the present invention may include a third connection device for connecting the first probe to a reference potential of the constant current source via the first connection device.
In the printed circuit board inspection method of the present invention, the first probe is connected to the reference potential of the constant current source at a time T3 before the predetermined time t31 from the time T1, and the predetermined time t14 has elapsed from the time T1. The first probe and the reference potential may be cut off at time T4 prior to time T2.
Prior to the potential measurement, the first probe is connected to the reference potential to discharge the charges charged in the wiring portion and the like, thereby eliminating the influence of charging and reducing the current from the constant current source for a short time. This makes it possible to carry out accurate inspection quickly.

In the printed circuit board inspection apparatus of the present invention, a conductor plate that is in contact with the conductor pattern of the printed circuit board via an insulating plate may be connected to a reference potential of the constant current source.
The quality of the contact state of the first probe with respect to the conductor pattern can also be inspected, and an accurate inspection can be carried out in a state where the first probe is reliably in contact with the conductor pattern.
In this case, an insulating plate prepared separately from the printed circuit board can be used. However, if there is a portion covered with an insulating film on the surface of the printed circuit board, this insulating film is used as an insulating plate, and a conductor is formed thereon. You may make it contact a board.

  According to the present invention, since the probe for detecting an electric signal is inspected as being in direct contact with the conductor pattern, the signal can be reliably detected and an accurate inspection can be performed.

It is a block diagram showing a schematic structure of a 1st embodiment of a printed circuit board inspection device concerning the present invention. It is a side view which shows the wiring state with respect to a printed circuit board in the printed circuit board inspection apparatus of FIG. It is a flowchart which shows the printed circuit board inspection method in 1st Embodiment. In 1st Embodiment, it is an electrical property figure which shows the time change of the electric potential of the 1st probe in case a conductor pattern is non-defective. In 1st Embodiment, it is an electrical property figure which shows the time change of the electric potential of the 1st probe in case a conductor pattern is inferior goods. In 1st Embodiment, it is another electrical characteristic figure in case a conductor pattern is a good product. In 1st Embodiment, it is another electrical characteristic figure in case a conductor pattern is inferior goods. It is a block diagram which shows schematic structure of the 1st modification with respect to the printed circuit board inspection apparatus of 1st Embodiment. It is a side view which shows the wiring state with respect to a printed circuit board in the printed circuit board inspection apparatus of FIG. It is a block diagram which shows schematic structure of the 2nd modification with respect to the printed circuit board inspection apparatus of 1st Embodiment. It is a side view which shows the wiring state with respect to a printed circuit board in the printed circuit board inspection apparatus of FIG. It is a block diagram which shows schematic structure of 2nd Embodiment of the printed circuit board inspection apparatus which concerns on this invention. It is a side view which shows the wiring state with respect to a printed circuit board in the printed circuit board inspection apparatus of FIG. It is a block diagram which shows schematic structure of 3rd Embodiment of the printed circuit board inspection apparatus which concerns on this invention. It is a side view which shows the wiring state with respect to a printed circuit board in the printed circuit board inspection apparatus of FIG. It is a block diagram which shows schematic structure of 4th Embodiment of the printed circuit board inspection apparatus which concerns on this invention. It is a side view which shows the wiring state with respect to a printed circuit board in the printed circuit board inspection apparatus of FIG. It is a flowchart which shows the printed circuit board inspection method in 4th Embodiment. In 4th Embodiment, it is an electrical property figure which shows the time change of the electric potential of the 1st probe in case a conductor pattern is non-defective. In 4th Embodiment, it is an electrical property figure which shows the time change of the electric potential of a 1st probe in case a conductor pattern is inferior goods. In 4th Embodiment, it is another electrical characteristic figure in case a conductor pattern is non-defective. In 4th Embodiment, it is another electrical characteristic figure in case a conductor pattern is inferior goods. It is a block diagram which shows schematic structure of 5th Embodiment of the printed circuit board inspection apparatus which concerns on this invention. It is a side view which shows the wiring state with respect to a printed circuit board in the printed circuit board inspection apparatus of FIG. It is a flowchart which shows the printed circuit board inspection method in 5th Embodiment. In 5th Embodiment, it is an electrical property figure which shows the time change of the electric potential of the 1st probe in case a conductor pattern is non-defective. In 5th Embodiment, it is an electrical property figure which shows the time change of the electric potential of a 1st probe in case a conductor pattern is inferior goods. In 5th Embodiment, it is another electrical characteristic figure in case a conductor pattern is non-defective. In 5th Embodiment, it is another electrical characteristic figure in case a conductor pattern is inferior goods. In 5th Embodiment, it is an electrical property figure in case a 1st probe has a poor contact with respect to a conductor pattern. In 5th Embodiment, it is another electrical characteristic figure in case the 1st probe has a poor contact with respect to a conductor pattern.

Embodiments of the present invention will be described below with reference to the drawings.
[About printed circuit boards]
The printed circuit board 1 to be inspected has various conductor patterns E1 to E4 formed on the surface or inside of the flat insulating layer 2. The insulating layer 2 may be a single layer or may be composed of a plurality of layers. When the insulating layer 2 is composed of a plurality of layers, the conductor patterns E1 to E4 also have a multilayer structure and are connected between upper and lower layers by vias or through holes. And both ends (electrode part) of each conductor pattern E1-E4 are provided in the surface of the insulating layer 2. FIG. In this case, both ends of the conductor patterns E1 to E4 may be provided only on one side or the other side of the printed circuit board 1, or may be provided separately on both sides. Further, at least one end portion of the conductor patterns E1 to E4 is exposed on the surface of the printed circuit board 1. The other end may be exposed on the surface of the printed circuit board 1 or may be covered with an insulating film.
In the drawings of the following embodiments, the printed circuit board 1 has conductor patterns E1 to E4 formed on the upper surface of the insulating layer 2, and both ends of each of the conductor patterns E1 to E4 are exposed on the surface of the insulating layer 2 of the printed circuit board 1. Is shown as being.

[First Embodiment]
As shown in FIGS. 1 and 2, the printed circuit board inspection apparatus 11 according to the first embodiment inspects a plurality of conductor patterns E1 to E4 of the printed circuit board 1 and generates a predetermined current. 12. Insulator 13 is provided at the other end of each of the plurality of first probes P1 to P4 and the conductor patterns E1 to E4 that are directly in contact with one end of each of the conductor patterns E1 to E4 exposed on the printed circuit board 1. A plurality of second probes P5 to P8 that are individually in contact with each other, a first connection device 14 having a plurality of changeover switches A1 to A4 for connecting the first probes P1 to P4 to the constant current source 12, respectively, and a fixed A second connection device 15 having a plurality of change-over switches B1 to B4 for connecting the second probes P5 to P8 to a reference potential (usually a ground potential) of the current source 12, respectively. A measurement circuit 16 for measuring the potentials of the first probes P1 to P4 with respect to the reference potential, a constant current source control unit 17 for controlling the constant current source 12, a connection device control unit 18 for controlling each connection device, An A / D conversion unit 19 and a potential measurement unit 20 connected to the measurement circuit 16, a main control device 21 and a display device 22 for controlling the control unit and the potential measurement unit are included. The main control device includes a CPU, a memory, an inspection condition setting unit, an inspection determination unit, and a data communication unit with each unit.

The printed circuit board inspection apparatus 11 brings the first probes P1 to P4 into direct contact with one end of the conductor patterns E1 to E4 exposed from the insulating layer 2 of the printed circuit board 1, and the second probes P5 to P8 to the conductor pattern E1. It arrange | positions through the insulator 13 at the other end of -E4.
As described above, the other end portions of the conductor patterns E1 to E4 may be exposed on the surface of the printed circuit board 1 or may be covered with an insulating film, but are exposed on the surface of the printed circuit board 1. In this case, when the second probes P5 to P8 are arranged with an appropriate insulator 13 interposed therebetween and the other ends of the conductor patterns E1 to E4 are covered with the insulating film, the insulating film is referred to here. As the insulator 13, the second probes P <b> 5 to P <b> 8 are brought into contact with this insulating film to be in a state of being disposed via the insulator 13. In the example of illustration, the 2nd probes P5-P8 are arrange | positioned through the insulator 13 at the edge part of the conductor patterns E1-E4.

  Thus, by arranging the first probes P1 to P4 and the second probes P5 to P8 and setting the changeover switches A1 to A4 of the first connection device 14 to the connected state, the first probes P1 to P1 are connected from the constant current source 12. It is assumed that a current is passed through P4. As a result, electricity is stored in the electrostatic capacity of the wiring section of the apparatus including the conductor patterns E1 to E4. As a result, the potential (constant value) measured by the measurement circuit 16 connected to the first probes P1 to P4. The potential of the first probes P1 to P4 with respect to the reference potential of the current source 12 is increased.

Next, the changeover switches B1 to B4 of the second connection device 15 are operated. If the conductor patterns E1 to E4 are normal, the operation of the second connection device 15 causes a change in the potential measured by the measurement circuit 16. When the conductor patterns E1 to E4 are disconnected, the potential measured by the measurement circuit 16 does not change even when the second connection device 15 is operated. By detecting the presence or absence of this potential change, the quality of the conductor patterns E1 to E4 can be identified.
The operation (ON / OFF operation) with respect to the changeover switches A1 to A4 and the changeover switches B1 to B4 is sequentially performed for the changeover switches corresponding to one of the conductor patterns E1 to E4, and the potential is changed for each of the conductor patterns E1 to E4. The presence or absence of a change is detected, and the quality is identified.

Details of this inspection will be described with reference to the flowchart of FIG. In the following description, each step will be described with reference numerals attached to the steps of the flowchart. In the following description, the conductor patterns E1 to E4, the changeover switches A1 to A4, and the changeover switches B1 to B4 are described, but unless otherwise specified, the conductor patterns E1 to E4 are sequentially inspected one by one. And
S1: First, the first probes P1 to P4 are brought into direct contact with one end of the conductor patterns E1 to E4. The second probes P5 to P8 are also arranged on the other ends of the conductor patterns E1 to E4 with an insulator 13 interposed.
S2: After arranging both probes P1 to P4 and P5 to P8, at time T1 (see FIG. 4 and the like), the first connecting device 14 is turned on, and current is supplied from the constant current source 12 to the first probes P1 to P4. Shed. Thereby, charging is started to the electrostatic capacitances of the wiring portions such as the conductor patterns E1 to E4 and the first probes P1 to P4 to which the first probes P1 to P4 are connected, and the potential measured by the measurement circuit 16 is increased. To rise.

S3: At time T2 when a predetermined time t12 has elapsed from time T1, the second connection device 15 is operated to change the connection state of the second probes P5 to P8 with respect to the reference potential of the constant current source 12. The change of the connection state means that when the changeover switches B1 to B4 of the second connection device 15 are in the OFF state, they are turned on, or the changeover switches B1 to B4 are in the ON state. Sometimes this is turned off.
S4: From the measurement result of the measurement circuit 16, it is determined whether or not the potential displacement amount per unit time tu at one end of the conductor patterns E1 to E4 has changed, and it is determined that the potential displacement amount per unit time tu has changed. If YES (YES), the process proceeds to S5. If it is not determined that the amount of potential displacement per unit time tu has changed (NO), the process proceeds to S8.

4 and FIG. 5, as shown in FIG. 4, as shown in FIG. 4, the potential displacement amount (the slope of the electrical characteristic graph) is changed at time T <b> 2 when the potential at one end of the conductor patterns E <b> 1 to E <b> 4 is rising. If it has changed (the potential displacement amount is small in FIG. 4), the process proceeds to S5, and if the potential displacement amount has not changed as shown in FIG. 5, the process proceeds to S8. The amount of potential change changes because the capacitance of the conductor patterns E1 to E4 with respect to the reference potential changes, and FIG. 4 shows an example in which the capacitance increases.
On the other hand, FIG. 5 shows a case where the change in potential displacement is not recognized even when the second connecting device 15 is operated at time T2, and in such a case, the process proceeds to S8.
Regarding the operation of the second connection device 15, whether the changeover switches B1 to B4 are switched from OFF to ON or from ON to OFF can be selected according to the characteristics of the substrate 1 to be inspected. It is sufficient to adopt an operation method in which the change in the value becomes large.

S5: determining that the potential of one end of the conductor pattern E1~E4 just before actuating the second connecting device 15, it is judged whether not reach open circuit voltage V ₀ which the constant current source 12, it has been reached on the open-circuit voltage V ₀ and when was (YES), the processing goes to S6, if it is not determined to have been reached on the open-circuit voltage V ₀ (the case of NO), the process proceeds to S7.
In the example shown in FIGS. 4 and 5, the potential does not reach the open circuit voltage V ₀ at the time T2, but in the examples illustrated in FIGS. 6 and 7, the potential reaches the open circuit potential V ₀ by the time T2. In such a case, the process proceeds to S6.
S6: It is determined whether or not the potential at one end of the conductor patterns E1 to E4 is displaced in the downward direction. If it is determined that the potential is displaced in the downward direction (in the case of YES), the process proceeds to S7, and is displaced in the downward direction. If not determined (NO), the process proceeds to S8.
In FIG. 6, the potential has reached the open circuit voltage V ₀ of the constant current source 12 before time T 2, and the potential instantaneously drops due to the operation of the second connecting device 15 (that is, the potential displacement amount is “0”). ”Changes in the direction in which the potential decreases). If the potential decreases as shown in FIG. 6, the process proceeds to S7. When the capacitance with respect to the reference potential of the conductor patterns E1 to E4 changes, the potential changes. FIG. 6 shows an example in which the capacitance is increased.

On the other hand, as shown in FIG. 7, case by operating the second connecting device 15 to change from open-circuit voltage V _0, the process proceeds to S8.
S7: The conductor patterns E1 to E4 are determined as non-defective products.
S8: The conductor patterns E1 to E4 are determined to be defective.
That is, the second probe P5 in which the potential displacement amount at one end of the conductor patterns E1 to E4 with which the first probes P1 to P4 are in direct contact is arranged via the insulator 13 at the other end of the conductor patterns E1 to E4. If the change is caused by the operation of the second connecting device 15 on the P8 side, the conductor patterns E1 to E4 are good products, and if the potential displacement does not change, it is judged as a defective product due to disconnection or the like.
Thus, since the potential is measured on the first probes P1 to P4 side that are in direct contact with the conductor patterns E1 to E4, the amount of potential displacement can be reliably detected, and an accurate inspection can be performed.

[First Modification of First Embodiment]
8 and 9 show a first modification of the first embodiment described above. In the first embodiment, the first connection device 14 includes a plurality of changeover switches A1 to A4 for connecting the plurality of first probes P1 to P4 to the constant current source 12, respectively. In addition, although a plurality of changeover switches B1 to B4 for connecting the plurality of second probes P5 to P8 to the reference potential of the constant current source 12 are provided, the printed circuit board inspection apparatus 11A of the first modification example The second connection device 15A has one changeover switch, and a plurality of second probes P5 to P8 are connected in parallel to the changeover switch B1. As for the first connection device 14, change-over switches A1 to A4 are connected to the conductor patterns E1 to E4, respectively.
This printed circuit board inspection apparatus 11A can reduce the cost by reducing the number of changeover switches.

[Second Modification of First Embodiment]
10 and 11 show a second modification of the first embodiment described above. In the case of the first modification, the changeover switch of the second connection device 15A is one. However, in the printed circuit board inspection device 11B of the second modification, the second connection device 15 is the same as in the first embodiment. A plurality of change-over switches B1 to B4 are provided, and one change-over switch is provided for the first connecting device 14A, and the first probes P1 to P4 are connected in parallel to the change-over switch A1.
In this printed circuit board inspection apparatus 11B, the cost can be reduced by reducing the number of changeover switches.

  In the following second embodiment and subsequent embodiments, as in the first and second modifications to the first embodiment, either the first connection device 14 or the second connection device 15 is used. The conductor patterns E1 to E4 may be connected in parallel to one changeover switch, and the other connection device may be a changeover switch for each of the conductor patterns E1 to E4.

[Second Embodiment]
12 and 13 show a printed circuit board inspection apparatus 31 according to the second embodiment. In this printed circuit board inspection apparatus 31, the second probes P5 to P8 and the changeover switches B1 to B4 of the second connection apparatus 15 are connected. Capacitors C1 to C4 having a predetermined capacitance are provided between them.
In the second embodiment, other configurations are the same as those of the first embodiment, and the same reference numerals are given and description thereof is omitted. Further, the printed circuit board inspection method by the printed circuit board inspection apparatus 31 of the second embodiment is the same as that of the first embodiment shown in FIG. 3, and the temporal change state of the potentials of the first probes P1 to P4 is also Although the absolute values and the like are different, they are the same as those in the first embodiment shown in FIGS. Similarly, in the following embodiments, the same reference numerals are given to common portions with the preceding embodiment, and the description will be simplified.
In the first embodiment, the potential displacement during the operation of the second connection device 15 occurs due to the capacitance of the wiring section itself including the floating capacitance, but in the second embodiment, the second probe P5 is used. By providing capacitors C1 to C4 having a predetermined capacitance between P8 and the second connection device 15, the change in capacitance when the second connection device 15 is activated is increased. Accordingly, the amount of potential displacement can be increased, and more accurate inspection can be performed.

[Third Embodiment]
14 and 15 show the printed circuit board inspection apparatus 41 according to the third embodiment. In the second embodiment described above, between the second probes P5 to P8 and the changeover switches B1 to B4 of the second connection apparatus 15. In this printed circuit board inspection apparatus 41, a predetermined voltage is provided between the changeover switches B1 to B4 of the second connection device 15 and the reference potential of the constant current source 12. Capacitors C5 to C8 having capacitance are provided. Only the positions where the capacitors C5 to C8 are provided are different from those of the second embodiment, and other configurations are the same as those of the second embodiment.
Therefore, in the third embodiment, the change in capacitance when the second connection device 15 is operated by the capacitors C5 to C8 provided between the second connection device 15 and the reference potential of the constant current source 12 is shown. By increasing the value and increasing the amount of potential displacement, a more accurate inspection can be performed.
The second embodiment and the third embodiment are combined to switch between the second probes P5 to P8 and the changeover switches B1 to B4 of the second connection device 15 and each change of the second connection device 15. The capacitors C1 to C4 and C5 to C8 may be provided between the switches B1 to B4 and the reference potential of the constant current source 12, respectively.

[Fourth Embodiment]
16 and 17 show a printed circuit board inspection apparatus 51 according to the fourth embodiment. This printed circuit board inspection device 51 is different from the printed circuit board inspection device 11 of the first embodiment in that a third connection device 23 having a changeover switch S between the first connection device 14 and the reference potential of the constant current source 12. Is provided. Other configurations are the same as those in the first embodiment.

FIG. 18 shows a flowchart of a printed circuit board inspection method using the printed circuit board inspection apparatus 51 of the fourth embodiment. In this flowchart, the same steps as those in the flowchart of FIG. 3 are denoted by the same reference numerals to simplify the description, and different steps are mainly described.
Further, changes in the potential of the first probe (one end of the conductor pattern) are shown in FIGS. 19 to 22. These FIGS. 19 to 22 correspond to FIGS. 4 to 7 of the first embodiment. Yes.
S11: At time T3 before time t31 from time T1, the third connecting device 23 is brought into a conducting state. As a result, the changeover switch S of the third connection device 23 is turned on, and when the wiring portion such as the first connection device 14 is charged, the charge is released.
S12: The time at which a predetermined time t14 has elapsed from time T1, and at time T4 before time T2, the third connecting device 23 is turned off (the changeover switch S is turned off). Since the first connecting device 14 is turned on in S2 before S12, charging is started on the first probes P1 to P4 side by setting the third connecting device 23 in the disconnected state in S12. As shown in FIGS. 19 to 22, the potential on the first probe P1 to P4 side rises.

19 and 20 show a case where the potentials of the first probes P1 to P4 are rising when the second connecting device 15 is operated. In the case shown in FIG. Since the potential displacement amount has changed, the process proceeds to S5. In the case shown in FIG. 20, the potential displacement amount has not changed at time T2, and thus the process proceeds to S8.
21 and 22 shows a case that has reached the open circuit voltage V ₀ which the potential of one end of the conductor pattern E1~E4 the constant current source 12 immediately before activating the second connecting device 15, the time as shown in FIG. 21 If a decrease in the potential is recognized at T2, the process proceeds to S7. If the potential does not change at time T2 as shown in FIG. 22, the process proceeds to S8.

  In the fourth embodiment, since the third connecting device 23 is provided, the inspection can be started after the third connecting device 23 is discharged even when the electrostatic capacitance portion in the wiring portion or the like is charged. Therefore, the potentials of the first probes P1 to P4 can be measured more accurately. In addition, since the first connecting device 14 is connected in a state where the first probes P1 to P4 are connected to the reference potential by the third connecting device 23 and then the third connecting device 23 is shut off, the conductor patterns E1 to E4 are connected. The value of the current from the constant current source 12 can be stabilized in a short time, and a faster inspection can be performed.

[Modification of Fourth Embodiment]
The printed circuit board inspection apparatus 51 according to the fourth embodiment shown in FIGS. 16 and 17 has a basic configuration, and, as in the second embodiment shown in FIGS. 12 and 13, the second probes P5 to P8 are connected to the second connection. Capacitors C1 to C4 may be disposed between the changeover switches B1 to B4 of the device 15, respectively.
Further, as in the third embodiment shown in FIGS. 14 and 15, capacitors C <b> 5 to C <b> 8 are disposed between the changeover switches B <b> 1 to B <b> 4 of the second connection device 15 and the reference potential of the constant current source 12, respectively. May be.
Moreover, you may arrange | position both these capacitors C1-C4, C5-C8.
In any case, the amount of potential displacement can be increased by the amount of capacitors C1 to C4 or C5 to C8, and more accurate inspection can be performed.

[Fifth Embodiment]
23 and 24 show a printed circuit board inspection apparatus 61 according to the fifth embodiment. In this printed circuit board inspection apparatus 61, the first probes P1 to P4 that are brought into direct contact with one end of the conductor patterns E1 to E4 of the printed circuit board 1 and the other ends of the conductor patterns E1 to E4 are disposed via the insulator 13. In addition to the two probes P5 to P8, a conductor plate 25 connected to the reference potential of the constant current source 12 is provided. In the example shown in FIGS. 23 and 24, the first probes P1 to P4 and the second probes P5 to P8 are all arranged on one surface side of the printed circuit board 1, and the conductor plate 25 is formed of the printed circuit board 1. Is in contact with the insulating layer 2 on the other surface of the first electrode and connected to the reference potential of the constant current source 12. In this case, the conductor plate 25 is formed in a size that can contact the entire surface of the insulating layer 2 of the printed circuit board 1, but at least a part of the conductor patterns E1 to E4 to be inspected via the insulating layer 2. What is necessary is just to be formed in the magnitude | size which can oppose.
When both ends of the conductor patterns E1 to E4 are provided separately on both surfaces of the printed circuit board 1 as described in the section “About the printed circuit board”, the second probes P5 to P8 are on the same side as the conductor plate 25. In the position where the conductor plate 25 is avoided, an insulating layer is interposed.

The flowchart in the case of inspecting the board by this printed circuit board inspection apparatus 61 is as shown in FIG. 25. In the initial preparation for the inspection, the first probes P1 to P4 are brought into direct contact with one end of the conductor patterns E1 to E4. When the two probes P5 to P8 are also arranged on the other ends of the conductor patterns E1 to E4 via the insulator 13, the conductor plate 25 is arranged on the surface of the insulating layer 2 of the printed circuit board 1 (S15) except for FIG. This is the same as that after S2 in the flowchart.
By disposing the conductor plate 25, when the first connecting device 14 is in a conductive state at time T1 and a current is passed from the constant current source 12 to the first probes P1 to P4 (S2), the conductor patterns E1 to E4 The capacitance existing between the conductor plate 25 is charged, and the potential detected by the measurement circuit 16 increases. Next, the second connection device 15 is operated at time T2 to change the connection state of the second probes P5 to P8 with respect to the reference potential of the constant current source 12.

FIG. 26 shows the first probe when the second connecting device 15 is operated when the capacitance of the wiring portion is extremely smaller than the capacitance between the conductor patterns E1 to E4 and the conductive plate 25. The change of the electric potential of P1-P4 is shown, The connection state of the electrostatic capacitance of the wiring part including the conductor patterns E1-E4 with respect to the electrostatic capacitance between the conductor patterns E1-E4 and the conductor plate 25 is shown. By changing, if the conductor patterns E1 to E4 are non-defective products, the amount of potential displacement per unit time tu decreases as the apparent capacitance changes. When the capacitance with respect to the reference potential of the conductor patterns E1 to E4 changes, the amount of potential displacement changes. FIG. 26 shows an example in which the capacitance has increased.
In the case where the conductor patterns E1 to E4 are defective, as shown in FIG. 27, even if the second connecting device 15 is operated, the potential displacement does not change and the state before the second connecting device 15 is operated. maintain.

On the other hand, when the capacitance of the wiring portion is larger than the capacitance between the conductor patterns E1 to E4 and the conductive plate 25, or the capacitance between the conductor patterns E1 to E4 and the conductive plate 25 If there is not much difference from the capacitance of the wiring portion, as shown in FIG. 28, if the conductor patterns E1 to E4 are non-defective by operating the second connecting device 15, the first probe P1. After the potential of P4 slightly decreases, the potential increases with a potential displacement amount smaller than the potential displacement amount before connection. When the capacitance with respect to the reference potential of the conductor patterns E1 to E4 changes, the potential changes. FIG. 28 shows an example in which the capacitance has increased.
When the conductor patterns E1 to E4 are defective, as shown in FIG. 29, even if the second connecting device 15 is operated, the potential displacement amount does not change and the state before the second connecting device 15 is operated. maintain.
When the capacitance of the wiring portion is larger than the capacitance between the conductive patterns E1 to E4 and the conductive plate 25, or when the electrostatic capacitance between the conductive patterns E1 to E4 and the conductive plate 25 is static If there is little difference between the capacitance, the potential displacement amount per time tu before actuating the second connecting device 15 is small, therefore, the potential of the first probe P1~P4 reaches the open voltage V ₀ However, the case where the potential has reached the open voltage V ₀ of the constant current source 12 before the time T2 is not illustrated, but the potential is the open voltage V of the constant current source 12 before the time T2. _{If 0} reached, the same as in the case such as the first embodiment, when the conductive pattern E1~E4 is good varied to descend from the open voltage V _0, if no change from the open voltage V ₀ is the conductor Patterns E1-E4 are defective .

[Modification of Fifth Embodiment]
In the case of the fifth embodiment shown in FIGS. 23 and 24 as well, the printed circuit board inspection apparatus 61 shown in these drawings is used as a basic configuration, and, as in the second embodiment shown in FIGS. Capacitors C1 to C4 may be disposed between the probes P5 to P8 and the changeover switches B1 to B4 of the second connection device 15, respectively.
Further, as in the third embodiment shown in FIGS. 14 and 15, capacitors C <b> 5 to C <b> 8 are disposed between the changeover switches B <b> 1 to B <b> 4 of the second connection device 15 and the reference potential of the constant current source 12, respectively. May be.
Moreover, you may arrange | position both these capacitors C1-C4, C5-C8.
In any case, the amount of potential displacement can be increased by the amount of capacitors C1 to C4 or C5 to C8, and more accurate inspection can be performed.

Furthermore, as in the fourth embodiment shown in FIGS. 16 and 17, a third connection device 23 having a changeover switch S may be provided between the first connection device 14 and the reference potential of the constant current source 12. .
By providing the third connecting device 23, even when the electrostatic capacitance portions such as the conductor patterns E1 to E4 are charged, the inspection can be started after the third connecting device 23 is discharged. It can be measured more accurately, and the current value from the constant current source 12 for the conductor patterns E1 to E4 can be stabilized in a short time, so that a faster inspection can be performed and more accurate. Inspection can be performed.

By the way, in 5th Embodiment and its modification, it can also detect whether the 1st probes P1-P4 are contacting the conductor patterns E1-E4 reliably.
FIG. 30 shows the fifth embodiment shown in FIGS. 23 and 24, in which capacitors C1 to C4 are arranged between the second probes P5 to P8 and the changeover switches B1 to B4 of the second connection device 15, respectively. Alternatively, in any device in which capacitors C5 to C8 are respectively disposed between the changeover switches B1 to B4 of the second connection device 15 and the reference potential of the constant current source 12, the first probes P1 to P4 are used. However, if the contact pattern E1 to E4 is poorly contacted, the apparent overall capacitance decreases due to the capacitance between the first probes P1 to P4 and the conductor patterns E1 to E4. rise, reaching up to the open-circuit voltage V ₀ in an instant. By detecting the rising state of this potential, the contact state of the first probes P1 to P4 can be detected.

FIG. 31 shows the case of a device incorporating the third connection device 23 in the fifth embodiment. When the third connection device 23 is cut off and a current is passed through the first probes P1 to P4 (time T4), When the first probes P1 to P4 are in poor contact, the potential rises abruptly as in FIG. 30. Therefore, the rising state can be detected to detect the contact state of the first probes P1 to P4.
If contact failure of the first probes P1 to P4 is detected from the rising state of the potential, the contact positions, postures, and the like of the first probes P1 to P4 may be adjusted again.

While the embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and various modifications can be made without departing from the spirit of the present invention.
For the predetermined times t12, t31, t14, and tu, it is possible to set an optimal time according to the electrical characteristics of the printed circuit board, and by the adjustment, the change in the potential displacement amount at one end of the conductor patterns E1 to E4 is made faster. It can be detected reliably, and a fast and accurate substrate inspection can be performed.
In addition, the capacitances of the capacitors C1 to C4 and C5 to C8 are set to optimum values according to the electrical characteristics of the printed circuit board, so that the change in potential displacement at one end of the conductor patterns E1 to E4 can be made faster. It can be detected reliably, and a fast and accurate substrate inspection can be performed.

DESCRIPTION OF SYMBOLS 1 ... Printed circuit board, 2 ... Insulating layer, E1-E4 ... Conductor pattern, 11 ... Printed circuit board inspection apparatus, 12 ... Constant current source, 13 ... Insulator, 14, 14A ... First connection apparatus, 15, 15A ... Second Connection device, 16 ... measurement circuit, 17 ... constant current source control unit, 18 ... connection device control unit, 19 ... A / D conversion unit, 20 ... potential measurement unit, 21 ... main control device, 22 ... display device, 23 ... 3rd connection apparatus, 25 ... conductor plate, P1-P4 ... 1st probe, P5-P8 ... 2nd probe, A1-A4 ... changeover switch, B1-B4 ... changeover switch, C1-C4 ... capacitor, C5-C8 ... Capacitor, S ... changeover switch, 31, 41, 51, 61 ... printed circuit board inspection device

Claims (7)

  In a printed circuit board electrical inspection apparatus that applies an electrical signal to a conductive pattern formed on a printed circuit board and inspects the quality of the conductive pattern, a first probe that contacts one end of the conductive pattern, A second probe disposed at the other end via an insulator, a constant current source, a first connection device for connecting the first probe to the constant current source, and the reference potential of the constant current source A printed circuit board comprising: a second connection device for changing an electrical connection state of the second probe; and a measurement circuit for measuring a potential of the first probe with respect to a reference potential of the constant current source. Inspection device.   A capacitor having a predetermined capacitance is connected between the second probe and the second connecting device, or between the second probe and the reference potential of the constant current source, or both. The printed circuit board inspection apparatus according to claim 1, wherein:   The printed circuit board inspection apparatus according to claim 1, further comprising a third connection device for connecting the first probe to a reference potential of the constant current source via the first connection device.   4. The conductor plate in contact with the conductor pattern of the printed circuit board via an insulator is connected to a reference potential of the constant current source. 5. Printed circuit board inspection equipment.   The first probe is directly brought into contact with one end of the conductor pattern, the second probe is disposed on the other end of the conductor pattern via an insulator, and at time T1, a current is supplied from a constant current source to the first probe. The electrical connection state of the second probe with respect to the reference potential of the constant current source is changed at a time T2 when a predetermined time t12 elapses from the time T1, and the reference potential of the constant current source at the time of the change is changed. A printed circuit board inspection method, wherein the quality of the conductor pattern is determined from the measurement result of the potential of the first probe.   When the electrical connection state of the second probe with respect to the reference potential of the constant current source changes, if the amount of potential displacement at one end of the conductor pattern per predetermined unit time tu changes, the conductor pattern is good. 6. The printed circuit board inspection method according to claim 5, wherein: The first probe is connected to the reference potential of the constant current source at a time T3, which is a predetermined time t31 before the time T1, and the first probe is connected at a time T4 after the predetermined time t14 from the time T1 and before the time T2. The printed circuit board inspection method according to claim 5 or 6, wherein one probe and the reference potential are cut off.

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