JP5510964B2 - Continuity inspection method - Google Patents

Description

  The present invention relates to a continuity inspection method for inspecting a continuity state of a wiring pattern or the like formed on a circuit board.

As this kind of continuity inspection method, for example, conventional techniques described in Patent Document 1 and Patent Document 2 are known.
FIG. 5 is a circuit diagram showing this prior art, in which 100 is an inspection apparatus main body, 11 is a current source, 12 is voltage detection means, 13 is current detection means, H _c , H _p , L _p , _Lc is a conducting wire, S ₁ and S ₂ are switches, and 21a, 21b, 22a and 22b are probes. R ₁ and R ₂ are inspection target portions to be inspected for continuity, and constitute, for example, a part of a wiring pattern formed on a circuit board.

FIG. 6 is an explanatory diagram of the inspection target part, where R _{11 to} R ₁₃ indicate inspection target parts, and T _{1 to} T ₄ indicate terminals at both ends of the inspection target part with which the probe contacts. The entire wiring pattern composed of one or a plurality of inspection target parts having the same potential is referred to as a net N, and exceptionally, a pattern composed of only one terminal is also included in the net N.
Hereinafter, the individual inspection target parts R _{11 to} R ₁₃ themselves are also called nets.

In the prior art shown in FIG. 5, for example, the switches S ₁ and S ₂ are connected to the conductive wires H _c and L _c as shown, and a relay switch (scanner switch) in the scanner board (not shown) is turned on. Then, a series connection circuit of the nets R ₁ and R ₂ is formed between the conductors H _c , H _p , L _p , and L _c via the probes 21a, 21b, 22a, and 22b, and the conduction state is inspected.
That is, as shown by a broken line in FIG. 5, the current source 11 on lead _{H c} connecting portion 31 → the probe 21a → net _{R 1} → probe 21b → wire _{H p} on the connecting portions 32, 33 → the probe 22a → net R ₂ → probe 22b → wire L _c on the connecting portion 34 → current detecting means 13 → a current flows in a path of ground, conductor H _c at that _time, by detecting the voltage between the L _c by the voltage detecting means 12 Ohm's Law Accordingly, the continuity test of the _two nets R ₁ and R ₂ connected in series is performed at once by obtaining the combined resistance value of the series connection circuit.

If the calculated combined resistance value is smaller than a preset threshold value, the inspection apparatus main body 100 determines that the conduction state is “good” (both nets R ₁ and R ₂ have the conduction state “good”) and determines “PASS”. A signal indicating “FAIL” is output when the signal indicating that the conduction state is “bad” (one or both of the nets R ₁ and R ₂ is “bad”) is determined. (it's shown.

According to the measurement principle described above, a maximum number of guard lines (ground guard lines) provided in the inspection apparatus main body 100 can be used as shown in FIGS. It is possible to inspect these conduction states simultaneously by connecting the _five nets R _{1 to} R ₅ in series. That is, since it is possible to inspect the continuity of n (n is an integer of 2 or more) nets connected in series at a time, when a current is passed through one net and a resistance value is measured (referred to as a standard continuity test). Compared to the above, it is possible to perform an n-fold speed continuity test in which the inspection speed is increased n times. In FIGS. 7A to 7D, G _c and G _p indicate guard lines.

FIG. 8 shows a connection state in the case where the continuity test of five nets is performed once according to the above-described prior art (5 × speed continuity test), and is for realizing the connection state of FIG. 7 (d). It is.
In FIG. 8, components having the same functions as those in FIG. Reference numeral 110 denotes an inspection apparatus main body, 10 denotes an HV (high voltage power supply) board, and 20 denotes a probe group.

Furthermore, 40 is a scanner board for connecting the nets R _{1 to} R ₅ via the probe group 20 between the conducting wires H _c , H _p , L _c , L _p and the guard lines G _c , G _p , and 41 is a parent. A relay switch 42 is a child relay switch provided on the net R _{1 to} R ₅ side from the parent relay switch 41.
By turning on the relay switch 41 and 42, conductors _{H c, H p, L c} , L p and the guard line _G c, _{G p} and a connection point between the probe group 20 (● mark portion in the figure) activity As a result, a net is connected between each connection point. When the relay switches 41 and 42 are turned on as shown in FIG. 8, a series connection circuit including _five nets R _{1 to} R ₅ is formed between the conductive wires H _c and L _c , and the same method as in FIG. A double speed continuity test can be performed.

JP 2008-46060 A (paragraphs [0027] to [0030], FIG. 3 etc.) Japanese Unexamined Patent Publication No. 2010-25871 (paragraphs [0002] to [0007], FIGS. 7 to 9 and the like)

However, as shown in FIG. 8, the larger the number of nets connected in series, the more relay switches 41 and 42 are interposed in the series connection circuit, and the switches S ₁ and S ₂ in the HV board 10 are also connected to these relays. The switches 41 and 42 are connected in series. From the characteristics of the scanner board 40, the child relay switch 42 is configured to be connected in parallel via the parent relay switch 41 in units of a large number of connection points. Depending on the connection location, the parent relay switch 41 and the child relay switch 41 may be connected. When the net is connected via the relay switch 42 and when the net is connected only through the child relay switch 42 because the parent relay switch 41 is common (for example, the nets R ₄ and R in FIG. 8). _In any case, a large number of switches are interposed in a series connection circuit of a plurality of nets.

  However, if the on-resistance value per one of these switches is about 10 [Ω], for example, the resistance value of the entire series connection circuit measured by the continuity test is the resistance value of the relay switch existing in the series connection circuit. The total on-resistance value for the number is added. In other words, if all the nets to be inspected are conductive, the resistance value that should be 0 [Ω] may be a value of 100 [Ω] or more in some cases, which cannot be ignored during inspection. It was.

  Accordingly, the problem to be solved by the present invention is to cancel the total on-resistance value of a plurality of switches existing in a series connection circuit of a plurality of nets, and to measure the true resistance value, thereby improving the inspection accuracy. It is to provide a method.

In order to solve the above-mentioned problem, in the invention according to claim 1, a plurality of nets which are conductive inspection target parts are connected in series via a plurality of switches driven by the control means at both ends of the voltage detection means. The current flowing from the current source to the series connection circuit of the net is detected by the current detection means, the voltage across the series connection circuit is detected by the voltage detection means, and the calculation means is determined by the current detection means. In the continuity inspection method for calculating the combined resistance value of the series connection circuit from the current detection value and the voltage detection value by the voltage detection means and inspecting the continuity state of the series connection circuit according to the magnitude thereof,
The computing means computes the on-resistance total value by the plurality of switches present in the series connection circuit, and the resistance value obtained by subtracting the on-resistance total value from the combined resistance value is negative, And when the absolute value is more than the ON resistance value of one said switch, it is judged that there exists a short circuit location in the said series connection circuit .

According to the present invention, the true combined resistance value of the series connection circuit is calculated by canceling the total ON resistance value of the plurality of switches such as relay switches existing in the series connection circuit of the plurality of nets. This can improve continuity inspection accuracy.
Further, based on the combined resistance value obtained as a result of canceling the on-resistance total value, it is also possible to detect the presence of a short-circuited portion in the series connection circuit and to output a warning or display thereof.

It is a flowchart which shows 1st Embodiment of this invention. In 1st Embodiment of this invention, it is a figure which shows a connection state in case the parent relay of a scanner board is common. It is a figure which shows the connection state of the net | network at the time of the 5 time speed conduction | electrical_connection test in 2nd Embodiment of this invention. It is a flowchart which shows the principal part of 2nd Embodiment of this invention. It is a figure which shows the connection state of the net | network at the time of the double speed conduction | electrical_connection test by a prior art. It is explanatory drawing of a net | network. It is a figure which shows the connection state of the net | network at the time of n-times-speed conduction test. It is a figure which shows the connection state of the net | network at the time of the 5 times speed conduction | electrical_connection test by a prior art.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
First, the continuity inspection method according to the first embodiment will be described with reference to the flowchart of FIG. The configuration of the continuity testing device is the same as that shown in FIG. 8, and a current source 11 for passing a current through a series connection circuit of a plurality of nets to be tested, and a resistance value of the series connection circuit Current detecting means 13 and voltage detecting means 12 for measuring the above, a plurality of parent relay switches 41 and child relay switches 42 which are turned on to form the series connection circuit, and driving these relay switches 41 and 42 Control means (not shown) for performing the calculation, and calculation means (not shown) for performing calculations of Equations 1 to 6 and the like to be described later. Here, the control means and the calculation means can be realized by a CPU or the like, for example.

In this embodiment, the number of switches existing in the series connection circuit of the net is obtained at the time of the n-fold speed continuity test, and the total on-resistance value of the switch is removed from the measured combination resistance value of the series connection circuit. A resistance value is obtained. Here, n is the number of nets connected in series, and is an integer of 2 or more.
Hereinafter, the procedure of the continuity test according to the present embodiment will be described with reference to FIG.

(1) The pair of input terminals of the voltage detecting means 12 in FIG. 8 are connected to the conducting wires H _c and L _c by turning on the switches S ₁ and S ₂ (step S1).
(2) When performing n-times speed (for example, 5 times speed) continuity inspection, one end of each of the nets R ₁ and R ₅ at both ends of the series connection circuit is connected to the pair of input terminals of the voltage detection means 12 via the conductive wires H _c and L _c. In order to connect, a parent relay switch 41 and a child relay switch 42 for connecting one end of the net R ₁ to the conductor H _c and an end of the net R _{5 to} the conductor L _c are connected by the operation of the control means. The parent relay switch 41 and the child relay switch 42 are turned on. That is, 2 × 2 = 4 relay switches are turned on (step S2).
(3) It is determined whether or not the parent relay is common to all the child relays in the scanner board 40 (step S3). That is, as shown in FIG. 2, the parent relay is commonly used when a series connection circuit of n nets is configured by only two parent relay switches 41 and a plurality of child relay switches 42 which are turned on in step S2. It is determined that the parent relay is not in common. Whether or not the parent relay is common can be known in advance from the specifications of the scanner board 40.

(4) If the parent relays are common (YES in step S3), as is apparent from FIG. 2, two child relay switches 42 are added between each of the nets connected in series via the conductors. Therefore, in addition to the four relay switches in step S2, 2 × (n−1) child relay switches 42 are added (step S4).
(5) If the parent relay is not common (NO in step S3), for example, in the case of FIG. 8, a parent relay switch 41 that is twice the number m of nets that do not have a common parent relay is further required. Therefore, after adding 2 × (n−1) child relay switches 42 as in step S4 (step S4a), 2m parent relay switches 41 are added (step S5).

Therefore, the number x of relay switches included in the net series connection circuit for performing the n-fold speed continuity test in steps S1 to S5 can be obtained by Equation 1 (step S6).
[Formula 1]
x = 2 + 2 * 2 + 2 * (n-1) + 2m
= 2 (n + m + 2)
In Equation 1, if the parent relay is common, m = 0.
If the on-resistance values of the switches S ₁ and S ₂ in the HV board 10 and the relay switches 41 and 42 in the scanner board 40 are both about 10 [Ω], the total on-resistance value r of all these switches is r. Becomes Equation 2 (step S7).
[Formula 2]
r≈20 (n + m + 2)

Thereafter, an n-fold speed continuity test is performed using the voltage detection means 12 and the current detection means 13 in FIG. 8, and the combined resistance value R ′ of n nets (5 in the example of FIG. 8) in series connection circuit is obtained. Measure (Step S8).
Then, as shown in Formula 3, the true resistance value R at the time of the n-fold speed continuity test is calculated by subtracting (cancelling) the on-resistance total value r obtained in step S7 from the measured combined resistance value R ′. (Step S9).
[Formula 3]
R = R′−r
In addition, what is necessary is just to perform the calculation of Numerical formula 1-Numerical formula 3 mentioned above by the calculating means which is not illustrated.
As described above, according to the present embodiment, it is possible to calculate the true resistance value R of the series connection circuit including a plurality of nets by canceling the total on-resistance value of the relay switch or the like, and based on the resistance value R. In addition, it is possible to perform an n-times speed continuity test with high reliability.

Next, a second embodiment of the present invention will be described.
According to the first embodiment described above, it is possible to perform the n-fold speed continuity test by canceling the total on-resistance value of the switches existing in the series connection circuit of a plurality of nets. In the second embodiment, Further, the present invention relates to a continuity inspection method for detecting an insulation failure (short circuit) between different nets and performing a warning, display, or the like.

FIG. 3 shows a net connection state in the case of conducting a 5 × speed continuity test in the same manner as FIG. 7 (d).
In FIG. 3, it is assumed that, for example, a connection point between the nets R ₁ and R _{2 and} a connection point between the nets R ₃ and R ₄ are short-circuited due to poor insulation (SC indicates a short-circuit path). As is apparent from FIG. 8, a plurality of relay switches are connected in series between the net R ₁ and the net R _2, and a plurality of relays are also connected between the net R ₃ and the net R _4. The switches are connected in series. A plurality of relay switches are also connected in series between the net R ₂ and the net R ₃ .
Therefore, when the short circuit path SC of FIG. 3 does not exist normally, the net R ₄ passes from the right end of the net R ₁ of FIG. 8 via the conductive wire H _p -net R ₂ -guard line G _c -net R ₃ -guard line G _p. The total on-resistance values of a large number of relay switches (12 in the example of FIG. 8) existing in the series connection circuit extending to the left end of FIG.

However, in the case where the short-circuit path SC exists, the total on-resistance value r in Equation 3 is simply based on the number of switches in the series connection circuit, even though the large number of relay switches are bypassed by the short-circuit path SC. Therefore, the amount of relay switches that are bypassed is included in the on-resistance total value r and is subtracted from the combined resistance value R ′ (excessively subtracted). The obtained resistance value R may be negative.
In such a case, when the resistance value R becomes negative, it may be determined as a “measurement error” and the continuity test may be terminated. However, a short circuit as shown in FIG. If it can be displayed or the like, the original purpose of the continuity test will be met.
The second embodiment of the present invention is based on the above background.

FIG. 4 is a flowchart showing the main part of the second embodiment, and corresponds to the processing following step S8 of FIG. 1 described above.
For example, in the 5 × speed continuity test shown in FIG. 3 (FIG. 8), the on-resistance total value r of the series connection circuit formed between both ends of the voltage detection means 12 is based on Equation 2 and Become.
[Formula 4]
r = 20 (n + m + 2) = 20 (5 + 4 + 2) = 220 [Ω]
This is a case where the parent relay is not common as shown in FIG. 8, and is a value when the ON resistance value of each relay switch is 10 [Ω].
On the other hand, when the connection points of the nets R ₁ and R _{2 and} the connection points of the nets R ₃ and R ₄ are short-circuited as shown in FIG. 3, the series actually measured by the voltage detection unit 12 and the current detection unit 13. The combined resistance value R ′ of the connection circuit is Equation 5, which corresponds to the value at the time of the double speed continuity test.
[Formula 5]
R ′ = 20 (2 + 4 + 2) = 160 [Ω]

Therefore, when the total on-resistance value r of Formula 4 is subtracted from the combined resistance value R ′ of Formula 5 according to Formula 3 described above, Formula 6 is obtained (step S9 in FIG. 4).
[Formula 6]
R = R′−r = −60 [Ω]
That is, it is abnormal that the value R regarded as the true resistance value obtained by subtracting the total on-resistance value of the switch from the combined resistance value measured by connecting a plurality of nets in series is negative. It is possible to determine that there is a short-circuit location due to insulation failure between different nets.
Here, since the on-resistance value of one switch is assumed to be 10 [Ω], for example, the resistance value R obtained by Equation 6 is −10 [Ω] or less (the resistance value is negative and its absolute value is If the value is 10 [Ω] or more), it is determined that a short circuit between different nets is sure, and the resistance value R and the fact of the short circuit are warned or displayed by an appropriate method (step S10 in FIG. 4 YES, S11). In particular, by displaying the resistance value R according to Equation 6 (for example, R = −220 [Ω] when the conductors H _c and L _c in FIG. 3 are short-circuited), the short-circuited location and range are predicted to some extent. Is also possible.

10: HV board 11: the current source 12: voltage detector 13: current detector 20: probe group 40: Scanner board 41: the parent relay switch 42: child relay switch 110: main testing device S _{1, S 2:} Switch R ₁ ~R _5: net (inspected portion)
_Hc , _Hp , _Lc , _Lp : Conductive wire _Gc , _Gp : Guard line SC: Short circuit path

Claims (1)

A plurality of nets, which are conductive test targets, are connected in series to both ends of the voltage detection means via a plurality of switches driven by the control means, and flow from the current source to the series connection circuit of the nets. The current is detected by the current detection means, the voltage detection means detects the voltage across the series connection circuit, and the calculation means calculates the current detection value from the current detection means and the voltage detection value from the voltage detection means. In the continuity test method for calculating the combined resistance value of the series connection circuit and inspecting the continuity state of the series connection circuit according to the magnitude thereof,
The computing means computes the on-resistance total value by the plurality of switches present in the series connection circuit, and the resistance value obtained by subtracting the on-resistance total value from the combined resistance value is negative, And when the absolute value is more than the ON resistance value of one said switch, it is judged that there exists a short circuit location in the said series connection circuit, The continuity inspection method characterized by the above-mentioned .

Images