JPS62194700A - Inspection of printed board - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Industrial Application Fields The present invention relates to a printed circuit board inspection method, and particularly to a method for inspecting the mounting state of components on a printed circuit board.

<Conventional technology> Conventionally, as a method for inspecting the condition of components mounted on a printed circuit board, the printed circuit board and the component were distinguished from the density difference between the color of the printed circuit board and the color of the component using an imaging device.
There is also a known method in which components are identified by the shadows of the components that appear on the printed circuit board99, and a method is known in which a fluorescent agent is applied in advance to the component mounting position on the printed circuit board to distinguish between the printed circuit board and the mounted component. .

<Problems to be Solved by the Invention> However, as mentioned above, the method of using the difference in color density between the printed circuit board and the components and the shadow of the component is difficult because the printed circuit board has differences in color and density due to differences in materials, and Copper foil patterns, solder resist mark printing, etc. have mixed hues and densities, and on the other hand, parts also have various hues and densities, so it is easy to distinguish all parts from printed circuit boards. In addition, there is a problem that the time required to perform the test becomes long and the device becomes expensive.

Furthermore, the method of applying a fluorescent agent in advance to a component mounting position IC on a printed circuit board has the problem that if the fluorescent agent is applied at a misaligned position, it is impossible to inspect for misalignment or missing parts.

SUMMARY OF THE INVENTION In view of the above-mentioned problems of the prior art, an object of the present invention is to provide a printed circuit board sound detection method that can accurately detect the state of mounted components on a printed circuit board regardless of the color of the printed circuit board or mounted components. do.

Means for Solving Problems> In order to solve the above problems, the present invention applies pre-flux containing a fluorescent agent tm onto a printed circuit board in advance, and images the components mounted on the printed circuit board. The method is characterized in that the mounted state of the components on the printed circuit board is inspected by comparing the captured component image with a reference image.

Practical Example> The present invention will now be described in detail with reference to the drawings. Figures 1 (a) and (b) show process diagrams according to the present invention, in particular, Figure 1 (a) shows the printed circuit board (bare board) manufacturing process, and Figure 1 (c) shows the component mounting inspection process.

In Figure 1 (a), a wiring pattern is formed on the printed circuit board through an etch resist printing hardening process, an etching process, and a solder resist process, and then a preflux containing a fluorescent agent is applied after the character ink printing process and the punching process. It is applied all over. The fluorescent agent mixed in this preflux is one that emits light when irradiated with ultraviolet rays, but daylight fluorescent agents can also be used. In addition, since preflux, circuit boards, and parts naturally emit a small amount of fluorescence, the fluorescent agent mixed in preflux is exposed to ambient light so that it can be easily photographed by the TV camera of the printed circuit board inspection equipment described later. Select a material that is strong enough not to be affected and weak enough that the edges of the part will not be blurred by fluorescence.

Next, in Fig. 1 (portion c), the printed circuit board coated with pre-flux mixed with a fluorescent agent as described above is used as a pre-flux to connect the terminals of the mounted components and the predetermined positions of the wiring pattern of the circuit board. Ruder paste or adhesive is applied by screen printing. In this case, a fluorescent agent is similarly mixed in the cream solder or adhesive, and this fluorescent agent is selected to emit fluorescence of the same intensity as the fluorescent agent in the preflux described above. However, it is desirable to select an organic fluorescent agent as this fluorescent agent so as not to weaken the adhesive strength of the solder or adhesive.

On the board that has been coated with adhesive paste or adhesive mixed with a fluorescent agent as described above, a small number of components are mounted on a component mounting device, etc., and the components are mounted in the correct position using a printed circuit board inspection device. The animals will be inspected to see if they are present. Thereafter, if the defective component is not mounted in the correct position, it is repaired, and then the process proceeds to a fixing process depending on the component connection material.

In the upper part of Figure 2, the chip component C is mounted on the printed circuit board P, which has been coated with glue or glue mixed with the fluorescent agent, and the entire surface has been coated with preflux mixed with the fluorescent agent as described above. FIG. 3 is a block diagram of a printed circuit board inspection apparatus that inspects whether components are correctly mounted on the printed circuit board P.

The inspection device shown in Fig. 3 uses a mercury lamp 1 as a light source, and the mercury lamp 1 transmits visible light, totally reflects ultraviolet light, and projects it onto the substrate P, and also causes preflux and unruly radiation on the substrate P. It has a dichroic mirror 2 that transmits visible light emitted by a fluorescent agent of paste or adhesive, and a TV camera 3 that captures an image transmitted through the dichroic mirror 2.

As shown in Fig. 2, the image captured by the TV camera 3 is that the part C is captured as a silhouette because the fluorescent material such as preflux on the substrate P emits light. Black and white TV right camera can be used.

This inspection apparatus further includes an XY stage 4 on which the substrate Pvi is placed and moves in the XY direction, a processing section 5, a substrate Pf, and characteristic parameters (coordinates, The general structure includes an input section 6 for inputting information (area, shape, center of gravity position, etc.) in advance, and an output section 7 for outputting test results such as a CRT or printer.

5 processing units, central processing unit N1 (CPU), TV Camilla 3
An image processing unit that A/D converts the image signal from the input unit to extract feature parameters of each component, an IIA moving unit of the XY stage 4, a data memo IJ that stores reference feature parameters from the input unit 6, and an execution program of the CPU. It has a memory that stores . Incidentally, the reference vF characteristic parameters for inspecting the board P can be inputted by teaching the input section, or by inputting the component mounting data used by the mounting device at the component mounting authority. Furthermore, since the present invention images the silhouette of a component, the processing unit 5, particularly the image processing unit, may have an inexpensive configuration.

In the above configuration, the image captured by the TV camera 3 is a highly accurate component position signal as shown in the lower part of Figure 2, and therefore the position information of the component C on the board PF can be easily extracted. It is possible to easily determine whether C is missing or out of position.

In addition, the judgment of part C is made by comparing the area of the missing part of part C with the area of the dirt parameter in the case of a missing part, and in the case of a positional deviation, it is made by the deviation of the shape and center of gravity position of the part C and the reference parameter. .

<Effects of the Invention> As explained above, in the present invention, preflux gold mixed with a fluorescent agent is coated on a printed circuit board in advance, and the entire silhouette of the parts mounted on this board is imaged continuously. Positional information of components relative to the board can be obtained with high precision, and therefore missing parts and misalignment of components can be detected completely accurately.

However, since the present invention images the silhouette of the component, it is not affected by the color of the printed circuit board or the component, and has the advantage that the inspection device can be constructed at a low cost.

[Brief explanation of drawings]

The first opening is a printed circuit board manufacturing process diagram according to an embodiment of the present invention, FIG. The explanatory diagram and IEB diagram for inspecting a board are block diagrams of a printed circuit board inspection apparatus according to the present invention. l...mercury lamp, 2...dichroic mirror,
3...TV camera, 4...XY stage, 5...
Processing section, 6... Input section, 7... Output section, P... Printed circuit board, C... Components.

Claims (2)

[Claims] (1) Pre-flux mixed with a fluorescent agent is applied onto a printed circuit board in advance, the silhouette of the components mounted on the printed circuit board is imaged, and this imaged component image is compared with a reference image. A printed circuit board inspection method characterized by inspecting the mounting state of components on the board. (2) The printed circuit board inspection method according to claim 1, characterized in that a fluorescent agent is mixed in advance into the solder or adhesive that connects the components to the printed circuit board.