JP2995716B1 - Substrate conduction inspection apparatus and its conduction inspection method - Google Patents

Abstract

A continuity inspection of printed wiring formed on both surfaces of a substrate is performed satisfactorily. SOLUTION: The printed circuit board 11 has a through hole 1.
3, the printed wiring 121 on the back surface and the printed wiring 122 on the front surface are formed so as to conduct. The first planar electrode 31 is disposed so as to face the end 124 of the printed wiring 122 on the surface, and the end 12
4 and the through-hole 13, the second flat electrode 32
Are arranged facing each other. Then, an electric signal whose level changes with time is applied to the end 1 of the printed wiring 121 by the voltage application unit 51 and the non-inverting amplifier 52 of the signal application unit 50.
23, at the same time, an electric signal having a level change opposite to that of the electric signal is applied to the second plane electrode 32, and the first plane electrode 31 is applied when these electric signals are applied.
Is good or bad by the conduction determining means 60 based on the electric signal generated at the end portion 123 and the end portion 124.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printed circuit board or the like formed such that printed wiring on one side and printed wiring on the other side are electrically connected to each other. The present invention relates to a continuity inspection apparatus for a substrate for inspecting the continuity of a conduction state and a continuity inspection method thereof.

[0002]

2. Description of the Related Art Generally, a printed circuit board (Printed Cir
When printed wiring is formed on a cuit board), before mounting electronic components, etc. on the board, whether the printed wiring has been formed normally by conducting a continuity test or insulation test using a board inspection device Inspections have been conducted. Conventionally, the probe is brought into contact with one end of the printed wiring,
A method has been proposed in which an electrode is arranged at a position facing the other end and a continuity test is performed using an electrostatic capacitance equivalently formed between the electrode and the printed wiring (Japanese Patent Laid-Open No. 10-2393).
No. 72).

[0003]

The above-mentioned conventional Japanese Patent Application Laid-Open No.
In the method described in JP-A-239372, a conduction defect may not be found on a printed circuit board for double-sided mounting in which printed wiring is formed on one side and the other side of the board, for example.

FIG. 10 is a view for explaining a conventional conduction test.
(A) is a plan view and (b) is a side view. In the figure, a printed wiring 1 on one side of a printed circuit board 100 is shown.
01 and the printed wiring 102 on the other side are electrically connected via the through hole 103, and the printed wirings 101 and 1
02 are formed so as to face each other on both sides of the printed circuit board 100. The quality of the printed wirings 101 and 102 is determined based on the electric signal generated on the plane electrode 105 when an electric signal is applied by the probe 104.

At this time, if the printed wiring 102 is disconnected as shown in the figure, the plane electrode 105 is a composite capacitance of the capacitances C ₁ and C ₂ , that is,

[0006]

## EQU1 ## C ₁ / C ₂ / (C ₁ + C ₂ ) is to be measured. When the printed wirings 101 and 102 are well formed, both ends of the capacitance C ₂ are short-circuited. because there, the planar electrode 105 will measure only the capacitance C _1.

Here, assuming that the area of the opposed conductor is S, the distance between the conductors is d, and the dielectric constant between the conductors is ε, the capacitance C is as follows.

[0008]

## EQU2 ## Since C = ε · S / d, the dielectric constant ε is determined by the area S of the opposing conductor and the distance d between the conductors if the dielectric constant ε is the same level.

On the other hand, in FIG. 10, if the distance between the plane electrode 105 and the printed wiring 102 is d ₁ and the thickness of the printed circuit board 100 is d ₂ , d ₂ > d _1.
It has become. The plane electrode 105 and the printed wiring 1
The area of the opposing portion between 02 and S _1, the area of the opposing portions of the printed wiring 101 and the printed wiring 102 When S _2, and has a S _2> S _1.

The ratio S ₂ / d ₁ is compared with the ratio d ₂ / d _1.
When S ₁ is large, the magnitude relationship between the capacitances C ₁ and C ₂ is

[0011]

## EQU3 ## C ₂ > C ₁ .

Here, when the ratio S ₂ / S ₁ is very large, C ₁ ≪C ₂ . In this case, the above equation 1 is

[0013]

C ₁ / C ₂ / (C ₁ + C ₂ ) = C ₁ / (C ₁ / C ₂ +1) ≒ C ₁

Therefore, the plane electrode 105 and the printed wiring 1
Since the capacitance formed between the capacitors 101 and 102 is almost the same in the case of a non-defective product and in the case of a disconnection failure, it is very difficult to determine the quality.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide a substrate continuity inspection device and a continuity inspection method capable of performing a continuity inspection of printed wiring formed on both surfaces of the substrate. Aim.

[0016]

According to a first aspect of the present invention, a printed wiring on one surface and a printed wiring on the other surface are formed through a penetrating portion penetrating from one surface of the substrate to the other surface. Signal applying means for applying an electric signal whose level changes with time to the first region on the printed wiring on one side, and a second region on the printed wiring on the other surface. A first plane electrode disposed opposite to the first surface; a second plane electrode disposed opposite to a portion between the second region and the through portion in the printed wiring on the other surface; Second signal applying means for simultaneously applying an electric signal having a phase change opposite to that of the signal to the second plane electrode, and the second signal applying means based on the electric signal generated at the first plane electrode when each of the electric signals is applied. 1 area and above It is characterized in that a conduction judging means for judging the quality of the conduction state between the 2 areas.

According to this structure, the printed wiring on one side is connected to the printed wiring on the other side through the penetrating portion penetrating from one side to the other side of the substrate, and the printed wiring on the other side is connected to the other side. A first planar electrode is disposed opposite to a second region on the printed wiring, and a second planar electrode is disposed opposite to a portion of the printed wiring on the other surface between the second region and the through portion. As a result, a capacitance is equivalently formed between the second region on the printed wiring on the other surface and the first plane electrode, and a capacitance between the second region and the through portion in the printed wiring on the other surface is formed. Capacitance is equivalently formed between the second plane electrode and the second plane electrode.

When an electric signal whose level changes with time is applied to the first region on the printed wiring on one side by the first signal applying means, the electric signal is simultaneously applied to the electric signal by the first signal applying means. Thus, an electric signal having a level change opposite to the phase change is applied to the second plane electrode.

At this time, when the first region of the printed wiring on one surface and the second region of the printed wiring on the other surface are electrically connected, the second region on the printed wiring on the other surface is connected to the first plane electrode. An electric signal determined by the capacitance equivalently formed between the first plane electrode and the first plane electrode.

On the other hand, when a disconnection occurs between the first area of the printed wiring on one side and the second area of the printed wiring on the other side, the connection between the printed wiring on one side and the printed wiring on the other side is made. Capacitance is equivalently formed between them.

Therefore, the electric signal applied to the first region is applied to the printed wiring on the other surface via the capacitance formed between the printed wiring on one surface and the printed wiring on the other surface. However, the printed wiring on the other surface has an opposite phase through the capacitance formed between the portion between the second region and the penetrating portion in the printed wiring on the other surface and the second plane electrode. Is applied.

That is, electric signals having phases opposite to each other are applied to the printed wiring on the other surface through the equivalently formed capacitances, so that the electric signals are mutually canceled. As a result, the electric signal generated at the first plane electrode is at a different level depending on whether the first region and the second region are conducting or disconnected, so that the quality of the printed wiring is reliably determined. Is determined.

According to a second aspect of the present invention, in the substrate continuity inspection apparatus according to the first aspect, the printed wiring on the other surface between the first plane electrode and the second plane electrode is further provided. It is characterized by comprising a third plane electrode arranged at a position facing the ground and grounded.

According to this structure, since the third plane electrode disposed between the first plane electrode and the second plane electrode and facing the printed wiring on the other surface is grounded,
Capacitance is not equivalently formed between the second plane electrode and the first plane electrode, so that the opposite plane electric signal applied to the second plane electrode affects the first plane electrode. Is shut off. Therefore, the level fluctuation of the electric signal generated in the first plane electrode is prevented, and the quality of the printed wiring is determined with higher accuracy.

According to a third aspect of the present invention, in the substrate continuity inspection apparatus according to the first aspect, the printed wiring on the other surface between the first plane electrode and the second plane electrode is further provided. A fourth plane electrode disposed at an opposite position; and third signal applying means for applying an electric signal generated at the first plane electrode to the fourth plane electrode when each of the electric signals is applied. And

According to this configuration, the electric current generated in the first plane electrode is applied to the fourth plane electrode disposed between the first plane electrode and the second plane electrode and opposed to the printed wiring on the other surface. Since the signal is applied, the influence on the first plane electrode by the opposite-phase electric signal applied to the second plane electrode is cut off. Therefore, the level fluctuation of the electric signal generated in the first plane electrode is prevented, and the quality of the printed wiring is determined with higher accuracy.

According to a fourth aspect of the present invention, in the apparatus for inspecting continuity of a substrate according to any one of the first to third aspects, the printed wiring is disconnected between the first area and the second area. The electric signal level applied to the printed wiring on the other surface by the second signal applying means via the capacitance formed between the printed wiring on the other surface and the second plane electrode is equal to the one level. The first signal applying means is set to be higher than the electric signal level applied to the printed wiring on the other surface via the capacitance formed between the printed wiring on the other side and the printed wiring on the other surface. It is characterized by being.

According to this configuration, when the printed wiring is disconnected between the first region and the second region, the capacitance is formed via the capacitance formed between the printed wiring on the other surface and the second plane electrode. The level of the electric signal applied to the printed wiring on the other side by the second signal applying means is changed via the capacitance formed between the printed wiring on one side and the printed wiring on the other side. Is set so as to be equal to or higher than the electric signal level applied to the printed wiring on the other side, so that the electric signal applied to the first plane electrode by the electric signal applied by the first signal applying means is changed. Will be countered.

Therefore, it is possible to secure a level difference of an electric signal generated in the first plane electrode between the case where the printed wiring on one side and the printed wiring on the other side are conducting and the case where the wiring is disconnected. As a result, the quality of the printed wiring is reliably determined.

According to a fifth aspect of the present invention, a printed circuit on one side is connected to a printed wiring on the other side through a penetrating portion penetrating from one side to the other side of the substrate. In the inspection method, an electric signal whose level changes with time is applied to the first region on the printed wiring on one side, and an electric signal whose level change is in opposite phase to the electric signal is applied to the other side. It is simultaneously applied via a capacitance to a portion between the second region and the through portion of the printed wiring via the capacitance, and is arranged to face the second region on the printed wiring on the other surface when each of the electric signals is applied. It is characterized in that the quality of the conduction between the first region and the second region is determined based on an electric signal generated at the plane electrode.

According to this method, the printed wiring on one side and the printed wiring on the other side are electrically connected to each other through the penetrating portion penetrating from one surface of the substrate to the other surface. An electric signal having a changing level is applied to a first region on a printed wiring on one surface, and an electric signal having a level change opposite to that of the electric signal is applied to a second region and a penetrating portion in the printed wiring on the other surface. At the same time via a capacitance.

At this time, when the first region of the printed wiring on one surface and the second region of the printed wiring on the other surface are electrically connected, the second region on the printed wiring on the other surface and the plane electrode are connected. An electric signal determined by the capacitance equivalently formed between the electrodes is generated at the plane electrode.

On the other hand, when a disconnection occurs between the first area of the printed wiring on one side and the second area of the printed wiring on the other side, the connection between the printed wiring on one side and the printed wiring on the other side is made. Capacitance is equivalently formed between them.

Therefore, the electric signal applied to the first region is applied to the printed wiring on the other surface via the capacitance formed between the printed wiring on one surface and the printed wiring on the other surface. However, to the printed wiring on the other surface, an electric signal of an opposite phase is applied to a portion between the second region and the penetrating portion in the printed wiring on the other surface via a capacitance.

That is, electric signals having phases opposite to each other are applied to the printed wiring on the other surface via the capacitance, and are canceled each other. The electrical signal is
Since the level is definitely different between the case where the region and the second region are conducting and the case where the line is disconnected, the quality of the printed wiring is reliably determined.

[0036]

FIG. 1A is a block diagram showing an electric configuration of a first embodiment of a substrate continuity inspection apparatus according to the present invention, and FIG. 1B is a plan view showing a planar electrode of a sensor section and a printed circuit. FIG. 3 is a plan view showing a positional relationship between substrates. 2A and 2B are diagrams showing a configuration of a sensor unit of the continuity inspection device, wherein FIG.
FIG. 2B is a side view showing a state where the printed circuit board is brought into contact with the printed circuit board to perform a continuity test. FIG. 9 is a diagram showing an example of a printed circuit board to be inspected, (a) is a plan view,
(B) is a side view.

As shown in FIG. 1, the substrate continuity inspection apparatus 10 includes a probe 20, a sensor unit 30, and a control unit 40. The control unit 40 includes a CPU, an electronic circuit, and the like.
As functional blocks, a signal application unit 50 and a conduction determination unit 60 are provided. The board continuity inspection device 10 performs continuity inspection of printed wiring formed on both surfaces of the printed circuit board 11 to be inspected.

As shown in FIG. 9, the printed circuit board 11
The upper printed wiring 12 is configured by connecting a printed wiring 121 formed on the back surface (one surface) and a printed wiring 122 formed on the front surface (other surface) via a through hole (through portion) 13. ing. Printed wiring 121,
Reference numeral 122 denotes an end (first area) 123 of the printed wiring 121 formed in parallel with the printed circuit board 11 therebetween.
The continuity between the printed wiring 122 and the end (second region) 124 is inspected.

Returning to FIG. 1, the probe 20 is configured to be movable in the direction of contact and separation with respect to the rear surface of the printed circuit board 11 and is connected to the signal applying means 50. To apply a voltage in contact with the.

As shown in FIG. 2, the sensor unit 30 has a first
Planar electrode 31, second planar electrode 32, and third planar electrode 33
And is configured to be movable in the direction of contact and separation with respect to the surface of the printed circuit board 11. The lower surface of the sensor unit 30 is covered with an insulating film 301 having a predetermined thickness d ₁ (for example, d ₁ = 0.03 mm in the present embodiment) made of, for example, a hard synthetic resin. The distance between the printed wiring 121 and each of the electrodes 31 to 33 is maintained at a constant dimension d ₁ in a state of being in contact with the substrate 11.

As shown in FIG. 1, the first plane electrode 31
The printed wiring 122 is disposed so as to face the end 124, and is connected to the conduction determining means 60. The second plane electrode 32 is disposed so as to face a portion between the end 124 of the printed wiring 122 and the through hole 13, and is connected to the signal applying unit 50. Further, the third plane electrode 3
3 is disposed between the first plane electrode 31 and the second plane electrode 32 so as to face the printed wiring 122;
Grounded. In FIG. 1, only the planar electrodes 31 to 33 of the sensor unit 30 are illustrated for convenience of description.

The signal applying means 50 of the control means 40 includes a voltage output means 51, a non-inverting amplifier 52 and an inverting amplifier 53, and input terminals of the non-inverting amplifier 52 and the inverting amplifier 53 are connected to the voltage output means 51. The output terminal of the inverting amplifier 52 is connected to the probe 20, and the output terminal of the inverting amplifier 53 is connected to the second plane electrode 32. Voltage output means 5
1 outputs a voltage signal whose level changes with time, for example, a voltage signal which changes stepwise. The non-inverting amplifier 52 amplifies the input voltage signal at a predetermined amplification rate without changing the phase.
Is to invert the phase of the input voltage signal and amplify it at a predetermined amplification factor.

With this configuration, voltage signals having phases opposite to each other are simultaneously applied to the probe 20 and the second plane electrode 32 from the non-inverting amplifier 52 and the inverting amplifier 53, respectively. The voltage output means 51 and the non-inverting amplifier 52 constitute a first signal application means, and the voltage output means 5
The 1 and the inverting amplifier 53 constitute a second signal applying unit.

The conduction judging means 60 includes an amplifier 61, a peak hold circuit 62, and a level judging means 63. The amplifier 61 amplifies the electric signal generated at the first plane electrode 31, the peak hold circuit 62 holds the maximum value of the amplified electric signal, and the level determination unit 63 includes, for example, a comparator. The conduction state is determined by comparing the held maximum value with a predetermined reference value.

Here, each of the planar electrodes 31 to 31 of the sensor section 30
The capacitance equivalently formed between the printed circuit board 33 and the printed circuit board 11 will be described. As shown in FIG. 1, the first plane electrode 31 and the end 12 of the printed wiring 122 are
The capacitance between the 4 C _1, C ₂ the capacitance between the printed circuit 122 of the rear surface of the printed wiring 121 and the surface when the printed circuit 12 is disconnected, the second planar electrode 3
2 and the printed wiring 122 on the surface are represented by C
_3. The capacitance between the third planar electrode 33 and the printed wiring 122 on the surface is defined as C ₄ .

In the present embodiment, the area of the second plane electrode 32 is set to be larger than the area of the first plane electrode 31 to increase the facing area between the second plane electrode 32 and the printed wiring 122. Thereby, as shown in FIG. 1, when the printed wiring 122 is disconnected at the disconnected portion A, each capacitance becomes

[0047]

[Formula 5] It is set so as to satisfy C ₁ ≪C ₂ C ₁ ≪C ₃ .

The printed circuit board 1 to be inspected is
Since the thickness dimension d _{2 of 1} is determined, within the range of d ₁ <d ₂ ,

[0049]

## EQU6 ## The sensor unit 30 and the printed circuit board 1 are arranged so as to satisfy C ₂ ≦ C _3.
Set the distance d1 from ₁ .

Next, the operation of the continuity inspection by the continuity inspection device 10 for the substrate thus configured will be described with reference to FIGS. 1, 3 and 4. FIG. FIG. 3 is an equivalent circuit diagram of the board continuity inspection device 10 and the printed circuit board 11, and FIG. 4 is a diagram showing output signals of respective parts of the equivalent circuit.

As shown in FIG. 4, when a voltage signal which changes with time is output from the voltage output means 51, the voltage signal is output from the non-inverting amplifier 52, and the end of the printed wiring 121 is passed through the probe 20. At the same time as being applied to 123, a voltage signal having a phase opposite to the applied voltage is output from the inverting amplifier 53 and applied to the second plane electrode 32.

At this time, when the printed wiring 122 is disconnected as shown in FIG. 1, as shown in FIG. 3, a voltage having a predetermined amplitude and an opposite phase is applied through the capacitances C ₂ and C _3. A signal will be applied to the printed wiring 122. Therefore, when C ₂ = C ₃ , the output signal of the amplifier 61 becomes almost zero as shown by the thick solid line P 1 in FIG. 4, and C ₂ <C ₃
In this case, the value becomes a negative value as shown by the thin solid line P2 in FIG.

On the other hand, in the case of a non-defective product in which the printed wiring 122 is not broken, the capacitance C ₂ is short-circuited in FIG. Since the voltage signal applied via the capacitance component C ₃ has almost no effect as compared with
The output signal of the amplifier 61, as shown in FIG. 4 in dashed line P3, the one that matches substantially the voltage signal applied through the capacitance C ₁ by the forward amplifier 52.

In FIG. 1, the maximum value of the output signal of the amplifier 61 is held by the peak hold circuit 62 and is compared with a predetermined reference value by the level determination means 63 to determine the quality of the printed wiring 12.

As described above, the second plane electrode 32 is provided so as to face the printed wiring 122, and a voltage signal having a phase opposite to that of the probe 20 is applied to the second plane electrode 32. In addition, it is possible to increase the level difference of the signal generated in the first plane electrode 31 between the case where the printed wiring 12 is good and the case where the printed wiring 12 is broken.

The first plane electrode 31 and the second plane electrode 3
Since the third plane electrode 33 is arranged between the first plane electrode 31 and the first plane electrode 31, the third plane electrode 33 is grounded. It can be prevented from being transmitted to the first plane electrode 31 via a capacitance component formed between the two plane electrodes 32.

Next, referring to FIGS. 5 and 6, a description will be given of a variation of the first embodiment in which a continuity test of a plurality of printed wirings is performed. FIG. 5 is a block diagram showing an electrical configuration of the present modification, and FIG. 6 is a diagram for explaining ON / OFF of a switch unit for each inspection count in the present modification. The same components as those in FIG. 1 are denoted by the same reference numerals.

In this modification, as shown in FIG. 5, the continuity test of the printed wirings 12a, 12b, and 12c is performed, and the probes 20a, 20b, and 20c are connected to the end portions 123a of the printed wirings 121a, 121b, and 121c on the back surface. , 1
A voltage signal is applied in contact with 23b and 123c.

This embodiment includes a switch section 70 composed of, for example, a transistor. The switch section 70 includes switches SW11, SW12, SW21, SW22, and SW3.
1, SW32, and the on / off of each switch is
It is controlled by the control means 40.

The probe 20a is connected to the switch SW
11 is connected to the output terminal of the non-inverting amplifier 52 via the switch 11 and grounded via the switch SW12.
0b is connected to the output terminal of the non-inverting amplifier 52 via the switch SW21 and grounded via the switch SW22, and the probe 20c is connected to the output terminal of the non-inverting amplifier 52 via the switch SW31 and It is grounded via SW32.

As shown in FIG. 6, the on / off of each switch of the switch section 70 is controlled by the control means 40, a voltage signal is applied from the probe 20a in the first inspection, and a voltage signal is applied from the probe 20b in the second inspection. In the third inspection, a voltage signal is applied from the probe 20c, and the printed wirings 12a, 12b, 12
The continuity test of c is performed in order.

The signal applying means 50 and the conduction judging means 60 operate in the same manner as in the first embodiment. Thus, according to the present modification, the same operation and effect as those of the first embodiment can be obtained, and the continuity test can be suitably performed.

FIG. 7 is a block diagram showing an electrical configuration of a second embodiment of the substrate continuity inspection apparatus according to the present invention. The same components as those in FIG. 5 are denoted by the same reference numerals. The substrate continuity inspection device 10 according to the second embodiment includes a printed wiring 122 between the first planar electrode 31 and the second planar electrode 32.
A fourth flat electrode 34 is provided at a position facing a, 122b, 122c instead of the third flat electrode 33. Also,
A non-inverting buffer (third signal applying means) 80 is provided. The input terminal of the non-inverting buffer 80 is connected to the first plane electrode 31, and the output terminal is connected to the fourth plane electrode 34.

In this configuration, the probe 20a (20b, 20c) and the second plane electrode 3
When a voltage signal is applied to 2, a voltage signal generated on the first plane electrode 31 is applied to the fourth plane electrode 34. Therefore, the first plane electrode 31 is replaced with the second plane electrode 32 by the fourth plane electrode 34 having the same potential as the first plane electrode 31 instead of the third plane electrode 33 grounded as in the first embodiment. The effect of the opposite phase voltage signal is blocked.

When the third plane electrode 33 grounded as in the first embodiment has a coupling capacitance with the first plane electrode 31, the voltage signal generated on the first plane electrode 31 is generated. Is attenuated by this coupling capacity. Therefore, there is an upper limit to the size of the opposing area of the printed wiring 12 for which the continuity test can be performed.

However, according to the second embodiment, since the fourth plane electrode 34 having the same potential as the first plane electrode 31 is provided instead of the grounded third plane electrode 33, no coupling capacitance occurs. In addition, it is possible to improve the upper limit value of the size of the facing area of the printed wiring 12 on which the continuity test can be performed.

The present invention is not limited to the above embodiments,
For example, the following modifications can be adopted. (1) Instead of the non-inverting amplifier 52 and the inverting amplifier 53, a non-inverting buffer and an inverting buffer each having an amplification factor of 1 may be used. In addition, the forward amplifier 52 and the inverting amplifier 5
3 may be interchanged with each other.

(2) Sensor part 30 and printed circuit board 1
By setting the distance d ₁ from C ₁ , C ₂ differs from
> When made in C ₃ may be larger than the amplification factor of the inverting amplifier 53 to the gain of the forward amplifier 52. For example, in the case of C ₃ ≒ C _2/2 may be set the amplification factor of the inverting amplifier 53 to 2 times the gain of the forward amplifier 52.

That is, the level of the voltage signal applied to the printed wiring 122 via the capacitance C ₃ is
_{If the} voltage is set to be equal to or higher than the level of the voltage signal applied to the printed wiring 122 via the line ₂ , as shown in FIG.
The output signal of the amplifier 61 when the wire is disconnected is indicated by a thick solid line P
It becomes zero or negative like 1 or the thin solid line P2, so that the quality of the printed wiring can be reliably determined.

(3) In the above embodiments, the voltage output means 51 outputs a stepwise changing voltage signal as shown in FIG. 4. However, the present invention is not limited to this. Any voltage signal whose level changes with time may be used.

(4) The signal applying means 50 is a voltage output means for outputting a voltage signal whose level changes with time similarly to the voltage output means 51, as shown in FIG. 8, instead of the structure shown in FIG. And a voltage output means 5 for outputting a voltage signal having a phase opposite to that of the voltage signal output from the voltage output means 54
5 and an output control means 56 for controlling these voltage output means 54 and 55 to output a voltage signal at the same time.

(5) In the second embodiment, the first plane electrode 31 is sandwiched by the fourth plane electrode 34 and further sandwiched by the second plane electrode 32, as shown by a chain line in FIG. You may comprise. Further, the first plane electrode 31 may be configured to be surrounded by the fourth plane electrode 34 and may be configured to be further surrounded by the second plane electrode 32 (not shown).

According to this embodiment, the influence of external noise on the first plane electrode 31 can be reduced, and the continuity test can be performed with higher accuracy.

(6) The printed circuit board to be inspected is not limited to the one shown in FIG. 9, and can be applied to a multilayer printed circuit board formed so that multilayer printed wiring is conducted.

[0075]

As described above, according to the first aspect of the present invention, the printed wiring on one side is electrically connected to the printed wiring on the other side via the penetrating portion penetrating from one surface of the substrate to the other surface. In the substrate formed as described above, the first plane electrode is disposed opposite to the second area on the printed wiring on the other surface, and the second plane electrode is disposed on the part between the second area and the through portion in the printed wiring on the other surface. And an electric signal whose level changes with time is applied to the first region on one side of the printed wiring by the first signal applying means, and at the same time, the level is changed with respect to the electric signal by the first signal applying means. Applied an electric signal of opposite phase to the second plane electrode,
The electric signal generated at the first plane electrode can be reliably set at different levels depending on whether the first region and the second region are conducting or disconnected, and thereby the quality of the printed wiring is good or bad. Can be reliably determined.

According to the second aspect of the present invention, the third plane electrode is arranged at a position between the first plane electrode and the second plane electrode and opposite to the printed wiring on the other surface. By grounding the plane electrode, an electrostatic capacitance is not equivalently formed between the second plane electrode and the first plane electrode. The effect on the first plane electrode due to this can be cut off. Therefore, it is possible to prevent the level fluctuation of the electric signal generated in the first plane electrode, and it is possible to more accurately determine the quality of the printed wiring.

According to the third aspect of the present invention, the fourth plane electrode is arranged between the first plane electrode and the second plane electrode at a position facing the printed wiring on the other surface. By applying an electric signal generated in the first plane electrode to the plane electrode, the influence on the first plane electrode due to the opposite-phase electric signal applied to the second plane electrode can be cut off. It is possible to prevent the level change of the electric signal generated at the electrode, and it is possible to determine the quality of the printed wiring with higher accuracy.

According to the fourth aspect of the present invention, when the printed wiring is disconnected between the first area and the second area, it is formed between the printed wiring on the other surface and the second plane electrode. The level of the electric signal applied to the printed wiring on the other side by the second signal applying means via the capacitance is changed via the capacitance formed between the printed wiring on the one side and the printed wiring on the other side. Since the level is set to be equal to or higher than the level of the electric signal applied to the printed wiring on the other surface by the first signal applying means, the electric signal applied by the first signal applying means should generate on the first plane electrode. The level difference of the electric signal generated in the first plane electrode between the case where the printed signal on one side is connected to the printed wiring on the other side and the case where the printed signal is disconnected due to the cancellation of the existing electric signal. Secure Bets can be reliably, which makes it possible to determine reliably the quality of printed wiring.

According to the fifth aspect of the present invention, an electric signal whose level changes with time is applied to the first region on the printed wiring on one side, and the level change of the electric signal is opposite to that of the electric signal. Is simultaneously applied to the portion between the second region and the penetrating portion in the printed wiring on the other surface via the capacitance, and the second electric signal on the printed wiring on the other surface is applied when each of the electric signals is applied. Since the quality of the conduction state between the first region and the second region is determined based on the electric signal generated at the plane electrode opposed to the region, the electric signal generated at the plane electrode is determined by the first region and the second region. The level can be reliably set to a different level depending on whether the connection with the second region is conducted or disconnected, and the quality of the printed wiring can be reliably determined.

[Brief description of the drawings]

FIG. 1A is a block diagram illustrating an electrical configuration of a first embodiment of a board continuity inspection device according to the present invention, and FIG. 1B is a plan view illustrating a positional relationship between a plane electrode of a sensor unit and a printed circuit board; FIG.

FIG. 2 is a diagram showing a configuration of a sensor unit of the continuity inspection device;
FIG. 2A is a plan view, and FIG. 2B is a side view showing a state where the printed circuit board is in contact with a printed circuit board for conducting a continuity test.

FIG. 3 is an equivalent circuit diagram of a board continuity inspection device and a printed circuit board.

FIG. 4 is a diagram illustrating output signals of respective units of the equivalent circuit of FIG. 3;

FIG. 5 is a block diagram showing an electrical configuration of the present modification.

FIG. 6 is a diagram illustrating ON / OFF of a switch unit for each inspection count in the modification of FIG. 5;

FIG. 7 is a block diagram showing an electrical configuration of a second embodiment of the substrate continuity inspection apparatus according to the present invention.

FIG. 8 is a block diagram showing a modification of the signal applying unit.

9A and 9B are diagrams illustrating an example of a printed circuit board to be inspected, wherein FIG. 9A is a plan view and FIG. 9B is a side view.

10A and 10B are diagrams illustrating a conventional conduction test, wherein FIG. 10A is a plan view and FIG. 10B is a side view.

[Explanation of symbols]

 REFERENCE SIGNS LIST 10 substrate continuity inspection device 20 probe 30 sensor unit 31 first plane electrode 32 second plane electrode 33 third plane electrode 34 fourth plane electrode 40 control means 50 signal application means 51 voltage output means 52 forward amplifier 53 inverting amplifier 60 Conduction determination means 61 Amplifier 62 Peak hold circuit 63 Level determination means

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁶ , DB name) G01R 31/02 G01R 31/28 G01R 27/00 G01R 1/06-1/073 H05K 3/00

Claims (5)

(57) [Claims] 1. A continuity inspection apparatus for a substrate formed so that a printed wiring on one surface and a printed wiring on the other surface are electrically connected to each other through a penetrating portion penetrating from one surface of the substrate to the other surface. First signal applying means for applying an electric signal whose level changes to a first region on the printed wiring on one surface; a first plane electrode opposed to a second region on the printed wiring on the other surface; A second planar electrode opposed to a portion of the printed wiring on the other surface between the second region and the penetrating portion, an electric signal having a level change opposite to that of an electric signal by the first signal applying means; A second signal applying unit for simultaneously applying a signal to the second plane electrode; and a signal between the first area and the second area based on an electric signal generated at the first plane electrode when each electric signal is applied. Good conduction Continuity testing device for the substrate, characterized in that a determining continuity determining means. 2. The continuity inspection device for a substrate according to claim 1, further comprising a position between the first plane electrode and the second plane electrode and opposed to the printed wiring on the other surface. A continuity inspection device for a substrate, comprising a grounded third planar electrode. 3. The continuity inspection device for a substrate according to claim 1, further comprising: a position between the first plane electrode and the second plane electrode and opposed to the printed wiring on the other surface. A continuity inspection apparatus for a substrate, comprising: a fourth plane electrode; and third signal applying means for applying an electric signal generated on the first plane electrode to the fourth plane electrode when each of the electric signals is applied. . 4. The printed wiring of the other surface according to claim 1, wherein the printed wiring is disconnected between the first area and the second area. An electric signal level applied to the printed wiring on the other surface by the second signal applying means via a capacitance formed between the printed wiring on the other surface and the other printed wiring via the capacitance formed between the printed wiring on the other surface and the second plane electrode. The electric signal level is set to be equal to or higher than an electric signal level applied to the printed wiring on the other side by the first signal applying means via a capacitance formed between the printed wiring on the other side. Substrate continuity inspection device. 5. A method for inspecting the continuity of a substrate formed such that a printed wiring on one surface is electrically connected to a printed wiring on the other surface through a penetrating portion penetrating from one surface of the substrate to the other surface. An electric signal whose level changes is applied to the first area on the printed wiring on the one surface, and an electric signal whose level change is opposite in phase to the electric signal is transmitted to the second area on the printed wiring on the other surface. An electric signal is simultaneously applied to a portion between the penetrating portion and the through-capacitance via an electrostatic capacitor. A method for inspecting the continuity of a substrate, wherein the quality of a continuity between the first area and the second area is determined based on the first and second areas.