JPH06268346A - Printed wiring board - Google Patents

Abstract

PURPOSE:To obtain a printed wiring board in which electric connection between each terminal of a component mounted on the surface of a printed wiring board and a corresponding conductor pad can be decided stably and positively. CONSTITUTION:A part 31 for opening a circuit routing a mounted component, a conductor pad, and conductive layers 21b, 22b is provided at a part of a conductor path 3a on the rear 4b of component mounting surface of a printed wiring board 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improved printed wiring board used for electronic circuits.

[0002]

2. Description of the Related Art FIG. 4 is a diagram showing an electronic circuit, in which 1 is a microcomputer, 11 is a power supply terminal of the microcomputer 1, 12 is an output terminal of the microcomputer 1, 2 is a logic IC, and 21 is a power supply terminal of the logic IC 2. , 22 are input terminals of the logic IC 2, 3 is a power supply line, and 11b and 21b are connection points to the power supply line 3 of the microcomputer 1 and the logic IC 2, respectively.

FIG. 5 shows a part of the internal configuration circuit of the microcomputer 1 and the logic IC 2.
The power supply terminal, output terminal, and input terminal of C2 are shown in FIG.
The same reference numeral is given. In the internal configuration circuit shown in FIG. 5, 1a and 1b are parasitic diodes that are necessarily formed in manufacturing. 6 and 7 are electronic circuit diagrams showing a state in which surface mount components are mounted and electrically connected to each other. In these figures, 4 is a printed wiring board which is a substrate, and 4a is a component mounting portion. The mounting surface 4b indicates the back surface thereof. 3a is a conductor path corresponding to the power supply line 3 shown in FIG. 4, 11a, 12a, 21a, 22a are power supply terminals 11, 21 of the microcomputer 1 and the logic IC 2, respectively.
A conductor pad corresponding to the output terminal 12 and the input terminal 22, 1
1b, 12b, 21b and 22b are conductor pads 11b,
A component mounting surface 4a, which is provided on both sides of the printed wiring board 4 and is provided on a conductor path continuous with 12b, 21b, and 22b, and its back surface 4
It is a conductive layer that penetrates b.

Next, the operation of the printed wiring board described above will be described. Generally, the printed wiring board 4 is used as a surface mounting method.
A thin iron plate (hereinafter referred to as a metal mask) having a hole corresponding to the conductive pad is placed on the component mounting surface 4a, and cream solder is applied onto the metal mask and printed with a roller to remove the metal mask. After removal, solder is attached to the perforated portions, that is, the conductor pads 11a, 12a, 21a, 22a.

In this state, the surface-mounted components, that is, the microcomputer 1 and the logic IC 2 in this case, are mounted on a position matching the predetermined conductor pad by an automatic mounting machine or by manual placement, and the reflow soldering device is mounted on a printed wiring board. 4 through each of the component terminals 11, 12, 21, 22 to the conductor pad 11a,
Solder to 12a, 21a, 22a. After that, the component terminals 1 are attached to the conductor pads 11a, 12a, 21a, 22a.
Visual inspection is performed to see if 1, 12, 21, 22 are securely soldered, and whether they are bridged. After the inspection is completed, a lead-through type connector for external connection, a socket with leads, etc. A discrete component (not shown) is inserted into the printed wiring board 4, and the back surface 4b of the printed wiring board 4 through which the terminals penetrate is soldered by, for example, a jet soldering device to be electrically connected.

In the above-mentioned inspection work, instead of the visual inspection, an in-circuit tester is used, test pins are applied to the conductive layers 11b, 12b, 21b, 22b on the back surface 4b of the printed wiring board, and the conductor pads 11a, 12a, 21a. Two
It is a well-known fact that the connection inspection between the 2a and the component terminals 11, 12, 21, 22 is being performed.

[0007]

However, since the conventional control device is configured as described above, for example, in the electronic circuit shown in FIG. 6 and FIG. When the connection between the conductor pad 21a of the logic IC 2 and the power supply terminal 21 and the connection between the conductor pad 22a and the input terminal 22 are confirmed by applying the test pin of 22a to the test pad 22b of FIG.
1, and the connection line between the conductor pad 12a and the output terminal 12 is interposed, and the parasitic diode 1b is also present, the power supply terminal 21 of the logic IC 2 is bent,
Even if it is broken and not connected to the conductor pad 21a, the above-mentioned conductive layer 22b test pin has the conductive layer 12b, the conductor pad 12a, the output terminal 12, the parasitic diode 1b, the power supply terminal 11, the conductor pad 11a, the conductive layer 11b, Also, it is connected to the test pin of the conductive layer 21b through the conductor path 3a and is judged as if it is connected.

In the above, the case where the unconnection of the power supply terminal 21 in the logic IC 2 cannot be confirmed has been described.
It is obvious that the same cannot be confirmed in the case of the input terminal 22, the power supply terminal 11 of the microcomputer 1, and the output terminal 12.

Therefore, in the conventional printed wiring board, it is necessary to visually check the connection between the component terminals and the conductor pads, which increases the number of inspectors, which leads to high costs due to personnel expenses and the like. There is a problem that defective products may occur due to the above.

The present invention has been made to solve the above problems, and an object thereof is to provide a printed wiring board capable of detecting unconnection.

[0011]

According to a first aspect of the present invention, there is provided a printed wiring board in which a conductor path is provided with a cutting portion for cutting the conductor path.

According to a second aspect of the present invention, there is provided a printed wiring board in which the cutting portion of the first aspect is formed in a sawtooth shape or a comb shape.

[0013]

According to the printed wiring board according to the first aspect of the present invention, the circuit which has been electrically connected by the component terminals, the parasitic diode inside the component and the conductor path of the conductor pad is cut off, and the unconnected state can be easily detected. can do.

Further, according to the printed wiring board of the second aspect of the present invention, in addition to the above operation, it is easy to plug the cut portion with solder, and it is easy to connect the cut portion after the continuity test.

[0015]

EXAMPLES Example 1. An embodiment of the present invention will be described below with reference to FIG. 1 and FIG. 6 described above. In FIG. 1, 31 is a cut portion provided so as to face a part of the conductor path 3,
Reference numeral 32 is solder for connecting the cutting portion 31 in the soldering process, and other portions are the same as those described in FIGS. 6 and 7, and the same objects are designated by the same reference numerals. 2 and 3 show the cutting portion 3
FIG. 3 is an enlarged view of a main part of No. 1 before soldering. The surface mounting method is as described in the related art, and the component mounting surface 4a of the printed wiring board 4 is in the same state as the electronic circuit shown in FIG.

A method of inspecting this electronic circuit will be described in detail. Similarly to the above, on the back surface 4b of the printed wiring board 4 of FIG. 1, one test pin is applied to the conductive layer 21b shown in FIG. 6 and the other test pin is applied to the conductive layer 22b, and the conductor pad 21a of the logic IC 2 and the power supply are connected. When confirming the connection between the terminal 21 and the conductor pad 22a and the input terminal 22, the conductive layer 22b, the conductor pad 22a, the input terminal 22, and the internal parasitic diode 1a of the logic IC 2 are included in the connection portion.
(FIG. 5), the power supply terminal 21, the conductor pad 21a, and the conductive layer 21b form a circuit. On the other hand, the conductive layer 12b includes the conductor pad 12a, the output terminal 12, and the microcomputer 1.
Connected to the power supply terminal 11 of the internal parasitic diode 1b (FIG. 5), the conductor pad 11a, and the power supply conductor path 3a of the conductive layer 11b, but the conductive layer 11b and the conductive layer 21b of the power supply conductor path 3a.
Since the cut portion 31 is provided between the two, it does not form a circuit and does not conduct with the test pin of the conductive layer 22b.

Therefore, the conductor pad 21a and the power supply terminal 2
1 and only the connection between the conductor pad 22a and the input terminal 22 can be determined, and if there is no connection in either or both of the conductor pad 21a and the power supply terminal 21, or the conductor pad 22a and the input terminal 22, this is detected as an abnormality. it can.

The conductive layer 21 with one test pin applied
By changing from b to the conductive layer 11b, the conductor pads 11a and 12 of the power supply terminal 11 and the output terminal 12 of the microcomputer 1 can be changed.
It goes without saying that the connection inspection of a can be performed.

As described above, in the electronic circuit, after the above-mentioned inspection is completed, a discrete component such as a lead-through type connector or a socket with a lead (not shown) is inserted therein, and a connection provided on the back surface of the printed wiring board through which this terminal penetrates. The land and the terminal are collectively passed through, for example, a jet-type soldering device, and a normal process for electrically connecting by soldering is performed. At this time, since the cut portion 31 is formed in a narrow slit shape, the cut portion 31 is easily closed by solder and short-circuited. Therefore, it is not necessary to electrically connect the cutting portion 31 by soldering as a separate operation, and the cutting portion 31 is inevitably performed in a normal soldering process and functions as an electronic circuit without changing equipment or performing different work. A practical device can be obtained.

Example 2. In the above embodiment, the case where the cut portions 31 provided in the opposite direction are formed in a narrow slit shape has been described, but the cut portions formed in a sawtooth shape may be provided as shown in FIG. Since the number of parts is large, it is extremely easy to close and short-circuit with solder during soldering.

Example 3. Further, instead of the sawtooth shape shown in FIG. 2, the same effect can be obtained by the comb-shaped cutting portion as shown in FIG.

[0022]

As described in detail above, according to the printed wiring board according to the first aspect of the present invention, since the conductor path is provided with the cut portion for cutting the conductor path, the component mounted on the surface is mounted. The effect that the connection inspection of the conductor pad of the terminal can be easily performed and highly accurate judgment can be obtained.

In addition, in the printed wiring board according to the second aspect of the present invention, since the cutting portion according to the first aspect is formed in a sawtooth waveform or a comb shape, in addition to the above effects, soldering can be extremely easily performed after the test is completed. It has the effect of being able to.

[Brief description of drawings]

FIG. 1 is a perspective view showing a first embodiment of the present invention.

FIG. 2 is an enlarged view of a main part showing a second embodiment of the present invention.

FIG. 3 is an enlarged view of a main part showing a third embodiment of the present invention.

FIG. 4 is a drawing showing an electronic circuit.

FIG. 5 is a circuit diagram showing a part of an internal configuration circuit of the IC.

FIG. 6 is a perspective view of an electronic circuit.

FIG. 7 is a perspective view of a conventional printed wiring board.

[Explanation of symbols]

 1 Microcomputer 2 Logic IC 3a Conductor path 11a, 12a, 21a, 22a Conductor pad 11b, 12b, 21b, 22b Conductive layer 11, 12, 21, 22 Terminal

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[Procedure amendment]

[Submission date] June 11, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Claim 1

[Correction method] Change

[Correction content]

[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be corrected] 0003

[Correction method] Change

[Correction content]

FIG. 5 shows a part of the internal configuration circuit of the microcomputer 1 and the logic IC 2.
The power supply terminal, output terminal, and input terminal of C2 are shown in FIG.
The same reference numeral is given. In the internal configuration circuit shown in FIG. 5, 1a and 1b are parasitic diodes that are necessarily formed in manufacturing. 6 and 7 are electronic circuit diagrams showing a state in which surface mount components are mounted and electrically connected to each other. In these figures, 4 is a printed wiring board which is a substrate, and 4a is a component mounting portion. The mounting surface 4b indicates the back surface thereof. 3a is a conductor path corresponding to the power supply line 3 shown in FIG. 4, 11a, 12a, 21a, 22a are power supply terminals 11, 21 of the microcomputer 1 and the logic IC 2, respectively.
A conductor pad corresponding to the output terminal 12 and the input terminal 22, 1
1b, 12b, 21b and 22b are conductor pads 11a ,
12 a, 21 a, 22 provided on the conductor path continuous with the a, component mounting surface 4a and the rear surface 4 is a double-sided printed circuit board 4
It is a conductive layer that penetrates b.

Claims (2)

[Claims] 1. A conductor path provided on both sides of a substrate, and a conductive layer which penetrates through the substrate at a plurality of appropriate places of the conductor path and connects the conductor paths provided on both sides of the substrate. A printed wiring board having a conductor pad for connecting a component mounted on the board to the conductor path, wherein the conductor path is provided with a cutting portion for cutting the conductor path. substrate. 2. The printed wiring board according to claim 1, wherein the cut portion is formed in a sawtooth shape or a comb shape.