JPS59119279A - Method and device for inspecting printed board - Google Patents

Abstract

PURPOSE:To make an electric connection securely without damaging a printed boared by interposing a pressure-sensing conductive elastic plate which becomes conductive where pressure is applied in its thickness direction between the printed board to be inspected and a terminal for inspection. CONSTITUTION:One surface of the pressure-sensing conductive elastic plate 3 which becomes conductive in its thickness direction where pressure is applied in the thickness direction is stacked upon one surface of the printed board 4 to be inspected, and a receiving plate 8 is stacked upon the other surface of the printed board 4 while a buffer material layer 81 made of sponge, etc., is interposed; and the terminal 2 for inspection which is held by a holding part 91 is arranged at a position corresponding to the through hole part 5 of the board 4, and the elastic plate 3 is pressed from the other surface side with a tip part 21 to make the board conductive as shown by a broken line, thus making the electric connection. Consequently, the electric connection is made without damaging the printed board.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a printed circuit board inspection method and apparatus.

In general, printed circuit boards include transistors,
Before incorporating functional elements such as diodes and resistors, it is necessary to inspect whether or not leads of the desired pattern have been formed. This inspection examines the presence or absence of electrical continuity between conductive parts (hereinafter referred to as "through-hole parts") formed around holes in which functional elements are inserted, that is, through-holes formed on printed circuit boards. This is done by

In an example of this conventional inspection method, for example,
As shown in FIG. 1, in an insulating terminal holding plate l.

Inspection terminals 2 made of, for example, metal pins are inserted so as to be movable forward and backward at positions if1'≦2 corresponding to the arrangement pattern of the snow hole portions 5 of the printed circuit board 4 to be inspected, and their tips are inserted. Inspection terminal 2 so that terminal 21 protrudes a considerable distance from the surface of terminal holding plate 1.
Each test terminal 2 is connected to a measuring device 6 having a computer, and each test terminal 2 is stacked and pressed against the printed circuit board 4 by pressing the terminal holding plate 1 on top of the printed circuit board 4. 2 through hole part 5
In this state, it is determined whether or not the null-hole portions 5 are electrically connected to each other by θM. The reason why the inspection terminal 2 is fully movable and the spring 100 is provided in the above-mentioned inspection device is that it can be used even for printed circuit boards 4 that are warped and/or have an uneven surface and are not completely flat. This is to bring each of the test terminals 2 into contact with the corresponding through-hole portion 5.

However, in such a so-called spring type inspection device, it is necessary to make each inspection terminal 2 movable and to provide a spring 100 for each inspection terminal 2, and moreover, the number of inspection terminals 2 is usually quite large. Because of this, manufacturing the spring 100 and its installation requires a considerable amount of effort, resulting in a disadvantage that the manufacturing cost of the inspection device becomes extremely high.

In addition, when conducting an inspection using such an inspection device,
It is necessary to ensure electrical contact between each of the inspection terminals 2 and the through-hole portion 5, but if the printed circuit board to be inspected has deformation such as warpage, the necessary inspection terminals 2
In order to reliably obtain a hypochondriacal connection state for all of
Depending on the condition of the test terminals 2, there is a large risk that the through-hole portion 5 may be damaged by excessive pressing force.For example, if the number of test terminals 2 is 1000 In this case, it is necessary to apply a large force of approximately 100 to 200 kg to the entire terminal holding plate 1 to press it against the printed circuit board 4, and therefore a large-sized suppression mechanism is required.

On the other hand, since the through-hole portions 5 of the printed circuit board 4 are stipulated to be positioned in a standardized board pattern, there is a possibility that the test terminals 2 are arranged in the board pattern, that is, the through-hole portions 5 are formed. There is also an inspection device called a universal type that is installed at all positions of the two pairs of windows.
Although it is advantageous in that it is a general-purpose device that can be applied to
The test terminals 2 come into contact with the parts where the test terminals 2 are not formed, and the spring method described above has the disadvantage that there is a large risk of damaging the printed wiring section.Moreover, the number of test terminals 2 required is small. The number of through-holes on the printed circuit board that need to be inspected is about 10 times larger than the number of through-holes that need to be inspected, so a large press machine is required for the suppression mechanism.In the end, the spring method described above makes the device universal. Difficult to automate as a mold.

The present invention was made against this background, and its purpose is to reduce the load per inspection terminal by extremely simple means without damaging the printed circuit board. To provide a method for inspecting a printed circuit board by which automation of an inspection device can be easily achieved, electrical connection with a conductive part of a printed circuit board can be reliably obtained, and highly reliable inspection can be performed. It is in.

Another object of the present invention is to provide a printed circuit board inspection device that is suitable for carrying out the above-described method, has a simple structure, and is low in cost.

The characteristics of the printed circuit board inspection method of the present invention are as follows:
A printed circuit board that is to be inspected on one side of a pressure-sensitive conductive elastic board whose portion that is subjected to pressure in its thickness direction becomes conductive, or an elastic board that has a number of mutually insulated conductive paths in its thickness direction. By pressing the portion of the elastic plate located on the conductive part of the mantissa of the printed circuit board with a plurality of test terminals, the test terminal and the conductive magnetic part of the printed circuit board are electrically connected. The test terminal is retractably held by a holding part of a terminal holding plate having a holding part made of an insulating elastic material.

The printed circuit board inspection apparatus according to the present invention is characterized by a pressure-sensitive conductor whose negative side is overlapped with the printed circuit board to be inspected, and whose part where pressure is applied in the thickness direction becomes a waxy state. A holder consisting of an elastic plate with a tail or a large number of mutually insulated rod electric paths in the thickness direction, and an insulating elastic material provided opposite to the other surface of the elastic plate with a gap therebetween. and a plurality of test terminals that are retractably held by the holding portion of the terminal holding plate and protrude from the terminal holding plate into the gap,
The plurality of test terminals include a group of test terminals arranged in accordance with the arrangement pattern of the conductive parts of the printed circuit board to be tested, and the terminal holding plate is arranged relative to the printed circuit board in a direction approaching the printed circuit board. There is a point e which is pressed by.

The present invention will be explained below with reference to the drawings.

In the method of the present invention, as shown in FIG. While overlapping one side of 3 on one side of the printed circuit board 4 to be inspected,
The board 8 is stacked on the other surface of the printed circuit board 4 via a cushioning material layer 81 made of sponge or the like, and an arbitrary through hole section is selected from among the plurality of through ball sections 5 of the printed circuit board 4. , the portion of the elastic plate 3 located on one of the through-hole portions is measured by a measuring device 6v including a computer.
The tip portions 21 of the plurality of test terminals 2 are connected to each other and are retractably held by the holding portion 91 of the terminal holding plate 9, which is formed by providing a holding portion 91 made of an insulating elastic material on a reinforcing plate 92, for example. so that the elastic plate 3 is pressed from the other side by
The terminal holding plate 9 and the receiver are pressed between the plate 8, and thereby the portion of the elastic plate 3 between the edge portion of the one through-hole portion of the printed circuit board 4 and each of the corresponding test terminals 2 is held. An elastic plate electrically connects the test terminal 2 and the one of the through-hole sections in a conductive state as shown by the broken line, and at the same time is located on the other of the pair of through-hole sections of MiJ. For the part 8, press it in the same way with another test terminal 2,
Thereby, the presence or absence of electrical continuity between the one through-hole section and the other through-hole section is inspected, and the printed circuit board 4 is thereby inspected.

In the present invention, in order to inspect the printed circuit board 4 as described above, the thing that is in contact with the surface of the printed circuit board 4 is the elastic plate 3.
Therefore, even when the test terminal 2 is pressed from the other side of the elastic board 3, the elastic board 3 disperses the pressing force by the test terminal 2, so that no local excessive force is applied to the printed circuit board 4. Since no force is applied, there is no risk of damage to the printed circuit board 4, and the printed circuit board 4 is inspected in a protected state, and the force applied to the test terminals 2 does not pinch the elastic plate 3 and cause it to deform. It is sufficient that the portion is large enough to be electrically conductive with the through-hole portion of the printed circuit board to be inspected, that is, the elastic plate 3 will actively come into close contact with the through-hole portion of the printed circuit board 4 due to its elasticity. Therefore, a highly reliable electrical connection can be obtained with a much smaller force than in the case of the conventional spring method, and the test terminal 2 can pinch the elastic plate 3 without requiring any special configuration. As long as it is a conductor with sufficient rigidity, benefits such as very low cost can be obtained.Also, when the printed circuit board 4 is warped and/or has an uneven surface and one side is not flat, Also elastic plate 3
Since one side follows and adheres closely to one side of the printed circuit board 4 due to the suppression of the test terminals 2, electrical connections between all through-hole portions 5 and the test terminals 2 are can be taken as a thing.

Furthermore, in the terminal holding plate 9, since the heights of the testing terminals 2 inevitably vary due to manufacturing, if the testing terminals 2 are fixed to the terminal holding plate 9, the height of the testing terminals 2 In order to absorb the main hole with the protruding height by the elastic plate 3 and press the test terminal with the lowest protruding height with the necessary pressing force, a considerable amount of force is required, and as a result, the overall diameter is too large. A certain amount of pressing force is required. In contrast, in the present invention, the test terminals 2 are provided so as to be retractable with respect to the terminal holding plate 9 by means of a holding part 91 made of an elastic material. It can be sufficiently absorbed by the displacement of the portion 91, and as a result, the pressing force of the test terminal 2 against the elastic plate 3 is absorbed by the test terminal 2.
Compared to the case where the terminal is fixedly installed, it is now significantly equalized, and is necessary in order to ensure the inspiratory connection between the test terminal 2 and the through-hole section 5. The overall pressing force applied to the terminal holding plate 9 can be reduced. As a result, the suppression mechanism can be downsized, and an automatic inspection device can be easily realized.

FIG. 3 shows a set 1 of the printed circuit board inspection apparatus of the present invention which can be suitably used to carry out the method of the present invention. In this example, a pressure-sensitive conductive elastic plate 3 that becomes conductive in the thickness direction when pressure is applied in the thickness direction is provided with a gap S between the other surface of the elastic plate 3 and the other surface of the elastic plate 3. A terminal holding plate consisting of an insulating reinforcing plate 92 made of a synthetic resin such as acrylic resin, phenolic resin, or epoxy resin, and a holding part 91 made of an insulating elastic material provided on the reinforcing plate 92. A plurality of test terminals 2, each connected to a measuring device 6 including a computer, are arranged on the terminal holding plate 9 in the form of a board pattern, that is, through holes. The tip portion 21 is pressed into all positions corresponding to the positions where the portion 5 may be formed, and the tip portion 21 is inserted into the holding portion 9 of the terminal holding plate 9.
1 and protrudes into the gap S from the surface of the holding portion 91.
This terminal holding plate 9 is provided to be held retractably by
For example, the elastic plate 3 and the terminal holding plate 9 are arranged such that the top surface of the tip end 21 of the test terminal 2 is in contact with the other surface of the elastic plate 3, and the terminal holding plate 9 is elastic. In order to be able to move toward the board 3, they are connected to each other at their peripheral portions by a connecting portion 7, thereby forming a printed circuit board inspection device.

This inspection device inspects printed circuit boards in the following manner, for example. That is, as shown in FIG. 4(a), the printed circuit board 4 to be inspected is stacked on one side of the elastic board 3, while the receiving board 8 is stacked on the other side of the printed circuit board 4 with a loose material layer 81 interposed therebetween. This receiver is used to fix the plate 8 as shown in Fig. 4 (
As shown in (B), the terminal holding plate 9 is pressed against the printed circuit board 4 by a suppressing mechanism (not shown) K until the gap S disappears, and as a result, the elastic plate 3 is pressed against each through hole of the printed circuit board 4. The elastic plate 3 is connected between the through-hole portion 5 and the inspection terminal 2 with the portion between the edge portion 5 and each inspection terminal 2 in a conductive state as shown by the broken line.
In this state, the presence or absence of electrical continuity between the through-hole portions 5 is inspected.

According to such a configuration, the corresponding test terminals 2 can be electrically connected to all desired through-hole portions 5 of the printed circuit board 4 at the same time via the elastic plate 3tl. As a result, the required inspection can be quickly and easily achieved, and as in the above example, the surface of the terminal holding plate 9 is pressed against the elastic plate 3 by the suppression of the terminal holding plate 9.
By keeping it in close contact with the surface of the terminal holding plate 9, parts of the printed circuit board 4 other than the through-hole portions 5 are pressed by the surface 52 of the terminal holding plate 9, so that the warpage of the printed circuit board 4 is corrected. Inspection can be carried out, and even if the lengths of protrusion from the holding part 91 of the respective test terminals 2 are uneven, each test terminal 2 can be retracted freely from the holding part 91 of the terminal holding plate 9. Since the test terminals 2 are held in place, the test terminals 2 are moved back by deforming the holding portion 91 according to the degree of the irregularity described above, so that the pressing force of the test terminals 2 against the elastic plate 3 can be made uniform. Therefore, the necessary electrical connection state can be obtained with a small overall pressing force applied to the terminal holding plate 9, and as a result, the required pressing mechanism can be small. , an automatic inspection device can be easily realized.

Furthermore, since there is no need to individually provide a spring for each test terminal 2, the structure is simple and compact, and as a result, the overall cost including the elastic plate 3 can be significantly reduced compared to the conventional one. I can do it. Furthermore, it is convenient for operation if the elastic plate 3 and the terminal holding plate 1 are integrally connected as in the embodiment.

The test terminal 2 used in the present invention may have its tip 21 formed into a spherical shape, but it may also be formed into a flat surface or a ring shape in cross section. In addition, when holding the test terminal 2 in the holding part 91 of the terminal holding plate 9, if the part of the test terminal 2 located in the holding part 91 is made medium thick or has a structure with protrusions, the test Since the terminal 2 is securely held by the holding portion 91, it does not easily come off, which is preferable. Further, the test terminal 2 may be formed by etching or the like, and the lead for connecting the test terminal 2 to the measuring device 6 may be taken from either the front or back side of the terminal holding plate 9. can.

In the above, the elastic plate 3 used in the present invention may be a pressure-sensitive conductive elastic plate whose portion becomes conductive when pressure is applied in the thickness direction, or a large number of conductive paths insulated from each other. There is an elastic plate having a direction, preferably the former elastic plate.

The former elastic plate is an anisotropic pressure-sensitive conductive rubber sheet whose main components are conductive particles and an insulating polymeric elastic material.
RPCRJ (manufactured by Japan Synthetic Rubber Co., Ltd.), and the latter's elastic plates each have a conductive path consisting of one or a bundle of filaments such as wire, carbon fiber, or carbon-containing 8M rubber, and each One in which conductive paths are arranged in a staggered pattern, one in which each conductive path is made of a filamentous body such as wire or carbon fiber, and each conductive path is arranged irregularly, and each 4 is arranged in a line. having conductive paths consisting of a large number of groups of metal particles and each conductive path being arranged irregularly; - having a large number of conductive paths consisting of a bundle of a large number of groups of metal particles arranged in rows, and each conductive path consisting of a bundle of a large number of groups of metal particles; A structure in which conductive paths are arranged in a grid pattern can be used.

In forming the holding portion 91 of the terminal holding plate 9, natural rubber, 8BR, BR, NBR, EFT, 11(.

Synthetic rubbers such as silicone rubber, sheets of polyester, polyimide and other polymeric substances, and composite materials of these with glass fibers, woven fabrics, non-woven fabrics and other reinforcing materials can be used.

In addition, the specific details of the thickness of the elastic plate 3, the thickness of the holding part 91 of the terminal holding plate 9, and the protrusion height of the test terminal 2 from the holding part 91 are as follows.
For example, the thickness of the elastic plate 3 is 0.3 to 20 fins, the thickness of the holding part 91 is 2 to 10+W, and the protrusion height of the test terminal is 01 to Q, 4mi. If a load of approximately 50 g is applied to each test terminal 2 to deform it, the test terminal 2 can be brought into a conductive state.

The device of the present invention also has a structure in which a recess 93 is formed in the holding part 91 at the boundary between the reinforcing plate 92 and the holding part 91 on the outer periphery of the test terminal 2, as shown in FIG. 5, or as shown in FIG. As shown in FIG. The retraction distance of terminal 2 can be obtained.

In pressing the test terminal 2 onto the printed circuit board 4 via the elastic plate 3, the pressure may be applied from either the test terminal 2 side or the printed circuit board 4 side. can be applied as is. Further, in a specific device, a cushioning material layer, a receiving plate, etc. can be provided integrally with the elastic plate and the terminal holding plate so as to be openable and closable.

The present invention is not limited to being applied to the calibration of through-pole portions of printed circuit boards, but can be applied to testing the electrical continuity between other conductive portions.

In addition, in the present invention, when the printed circuit board to be inspected has conductive parts on both sides, elastic plates are arranged on both sides of the printed circuit board and the printed circuit board is sandwiched between the terminals for inspection. may be made to act,
According to such an inspection method, it is possible to perform the required inspection on both sides of the printed circuit board at the same time, or it is also possible to easily inspect the electrical connection state between the conductive parts on the front surface and the conductive parts on the back surface. can be done.

As described above, according to the present invention, automation of the inspection device can be easily achieved by using extremely simple means without damaging the printed circuit board and reducing the load per inspection terminal. It is possible to provide a method for inspecting a printed circuit board that can reliably obtain electrical connection with the conductive part of the printed circuit board and to perform a highly reliable inspection. It is possible to provide a printed circuit board inspection device that is suitably used in the industry, has a simple structure, and is low in cost.

[Brief explanation of drawings]

FIG. 1 is a vertical cross-sectional side view showing a conventional printed circuit board inspection device, FIGS. 2 (a) and (b) are explanatory diagrams showing step by step the method for inspecting a printed circuit board according to the present invention, and FIG. 4(a) and 4(b) are explanatory diagrams showing step-by-step the implementation of printed circuit board inspection by the apparatus shown in FIG. 3, FIGS. 5 and 6 are explanatory cross-sectional views showing essential parts of other embodiments of the apparatus of the present invention. 1... Terminal holding plate 2... Inspection terminal 3...
Elastic plate 4-79 Client board 5...Through hole part 6...Measuring instrument 7...Connecting member 8...
The receiver is a plate 81...buffer material layer 9...terminal holding plate 9
1... Holding part 92... Reinforcement plate 93...
Concave Shelf I Illustration 4 (A) 5 Figure 4 ([1)

Claims (1)

[Scope of Claims] 1) A pressure-sensitive conductive elastic plate whose portion in the thickness direction becomes conductive when pressure is applied, or an elastic plate having a large number of mutually insulated conductive paths in the thickness direction. A voltage is applied to one side of the printed circuit board to be inspected, and a portion of the elastic plate located on the plurality of conductive parts of the printed circuit board is pressed by a plurality of inspection terminals, thereby connecting the inspection terminals and the printed circuit board. The process of electrically connecting the conductive part to the conductive part is characterized in that the test terminal is held retractably by a holding part of a terminal holding plate having a holding part made of an insulating elastic material. How to inspect printed circuit boards. 2) its - side is superimposed on the printed circuit board to be inspected;
A pressure-sensitive conductive elastic plate that becomes conductive when pressure is applied in its thickness direction, or an elastic plate that has a number of mutually insulated conductive paths in its thickness direction, and the other side of this elastic plate. a terminal holding plate having a holding part made of an insulating elastic material provided opposite to each other with a gap in between; a plurality of protruding test terminals, the plurality of test terminals including a group of test terminals arranged in accordance with an arrangement pattern of equal chambers of a printed circuit board to be tested; A printed circuit board inspection device characterized in that the holding plate is relatively pressed in a direction toward the printed circuit board.