JPS63177042A - Detection system for non-soldered part in mounted printed circuit board automatic inspection apparatus - Google Patents

Abstract

PURPOSE:To enhance the detection accuracy of solder non-wetting, by a method wherein beam is allowed to irradiate all of the soldered parts of the chip part mounted on a printed circuit board to be inspected and the total receiving quantity of the sputter beams of the beams from the soldered parts is detected. CONSTITUTION:Finely converged beam B is allowed to irradiate a printed circuit board P to be inspected and the sputter beam of the beam from the printed circuit board P is detected by a beam receiving part 13 to perform the inspection of the printed circuit board P. The beam receiving part 13 has a beam receiving surface S having a shape covering the chip part T mounted on the printed circuit board P and the sputter beams reflected from the soldered parts of the chip part T are detected by a large number of the beam receiving elements arranged to the entire beam receiving surface S. Then, the beam B is allowed to irradiate all of the soldered parts H1, H2 of the chip part T mounted on the printed circuit board P and the sputter beams L1, L2 of the beams B from all of the soldered parts H1, H2 are received and non-soldered parts are detected on the basis of the total receiving quantity of said beams.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention sweeps a narrowly focused beam spot of a laser beam or the like on a mounted printed circuit board, and prevents soldering from forming on the mounted printed circuit board due to defective soldering. The present invention relates to a solder flange detection method in a mounted printed circuit board automatic inspection device that automatically detects the presence or absence of solder flange.

[Conventional technology]

Conventionally, in soldering on mounted printed circuit boards, a head with a large number of pins arranged to match the component holes of the printed circuit board is used to detect bridging or poor bonding due to defects, and this head is used to detect the pins to be inspected. There is a contact inspection method that detects defective parts by checking the conduction state between each pin by contacting the solder surface of a printed circuit board. However, with this method, it is necessary to prepare a head for each type of printed circuit board, and the spacing between the pins of the head is limited by the thickness of the pins, so it is necessary to prepare a head for each type of printed circuit board. There is a problem in that it is difficult to inspect printed circuit boards with dense patterns, such as mounted printed circuit boards.

In order to solve the above problems, a beam such as a laser beam is scanned to sweep the beam spot on the printed circuit board to be inspected, and the sputtered light (reflected light) of this beam spot is
A non-contact type automatic mounted printed circuit board inspection device for detecting bridges and the like was proposed by the present applicant and disclosed in JP-A-61-76940.

[Problem that the invention seeks to solve]

When testing flat packages, etc., in which the leads are soldered to the conductive thin layer of the printed circuit board using solder paste, etc., using the contact inspection method described above, it is found that the chip leads and the thin conductive layer of the printed circuit board are not properly bonded due to solder flange. Even if there is a spot, the chip lead and the printed pattern are pressed against each other by the pin of the head, so it is determined that the solder joint is normally performed, and there is a problem that solder flange cannot be detected.

In addition, in the above-mentioned device proposed by the present applicant, a laser beam is irradiated to the component hole in order to detect solder flange of a chip component mounted on a printed circuit board, and when the laser beam passes through the component hole, However, it is an object of the present invention to detect solder bulges by detecting sputtered light from a solder portion and checking the state of solder adhesion.

[Means for solving problems]

FIG. 1 is a diagram illustrating the solder flange detection method in the mounted printed circuit board automatic inspection apparatus of the present invention. In an automatic printed circuit board inspection device that inspects printed circuit boards by irradiating a beam onto the printed circuit board to be inspected and detecting the sputtered light of the beam from the printed circuit board to be inspected, The beam B is irradiated onto all the solder parts H of the chip component T that has been soldered, the sputtered light of the beam from all the solder parts is received, and solder flange is detected based on the amount of the received light. .

[Effect]

FIG. 2 is a diagram showing changes in the intensity of sputtered light received in the detection method of the present invention shown in FIG. 1,
For example, when a laser beam is swept and irradiated onto a chip component T, if no solder flange occurs, the output portion S1 of the sputtered light L1 reflected by the solder portion H1 and the output portion S1 of the solder portion H2 as shown in FIG. Since an output portion S2 is obtained by the reflected sputtering light L2, the amount of light heard and received is the sum of the output portion S1 and the output portion S2. However, as shown in FIG. If this is the case, the amount of light heard and received will not be the same even if there is an output part 83 due to sputtered light from the corner of the chip component because the output of any one of the output parts S1 and S2 will not be obtained. There will be fewer solder creases than if they had not occurred, so
Solder flange can be detected by detecting the amount of sputtered light from all the solder parts and comparing it with the amount of received light of a preset standard.

〔Example〕

FIG. 3 is a front view showing the entire mounted printed circuit board automatic inspection device to which the present invention is applied, in which 11 is a casing;
Reference numeral 2 denotes an X-Y stage on which a printed circuit board P, which is an object to be inspected, is placed inside the casing and is freely moved in the X-axis direction and the Y-axis direction. As will be explained later, a light receiving section 13 is arranged above the X-Y stage 12 and detects sputtered light from the printed circuit board P to be inspected, and a large number of light receiving elements are arranged on the internal light receiving surface. . Reference numeral 14 denotes a light receiver installed below the X-Y stage 12, and when setting a reference point on a printed circuit board, a laser beam that hits the light receiving section 13 by 1fflJ is transmitted through a reference hole provided on the printed circuit board. It receives light through the 15 is a group of operation switches provided on the top surface of the casing 11; 16 is an indicator light indicating the operating status of the device;
7 is a printer that prints out the test results.

In this mounted printed circuit board automatic inspection device, inspection data such as a board name for identifying the reference position, inspection position, or type of printed circuit board on the printed circuit board to be inspected is registered in advance in a storage device etc. prior to inspection. When performing an inspection, place the printed circuit board to be inspected on the X-Y stage 12 and input the board name etc. from a terminal device (not shown). When the inspection is completed, the printer 17 prints out the inspection results such as the location or number of solder creases detected, and a mark (not shown) is placed near the solder crease locations on the printed circuit board to be inspected. .

FIG. 4 is a perspective view showing the optical system of the apparatus shown in FIG.
This is an expander for partially expanding the laser beam emitted by the Ne laser gun 21 into a parallel beam of approximately 5 diameters. 2
Reference numeral 3 denotes a Y-axis rotating mirror 23a that scans the laser beam so that the beam spot is swept in the Y-axis direction of the X-Y stage 12, and a Y-axis rotating mirror 23a that scans the laser beam so that the beam spot is swept in the X-axis direction. This is a galvanometer equipped with a scanning X-axis rotating mirror 23b, and the laser beam is scanned by this galvanometer 23 based on the movable range of each rotating mirror (within a solid angle. 24 is operated by the galvanometer 23). This is a condensing lens that condenses a laser beam onto a printed circuit board P via a first mirror 25 and a second mirror 26.

As shown in FIG. 1, the light-receiving section 13 has a light-receiving surface S that is shaped to cover a chip component T mounted on a printed circuit board. Sputtered light reflected from the solder portion of the chip component is detected by the light receiving element.

In addition, the light receiving element 13 is also provided with a light receiving element on the upper light receiving surface, but considering that the sputtered light from the solder part is reflected at a relatively low angle, the light receiving element on the side surface is This is to receive sputtered light to avoid erroneous detection due to variations in the amount of received light due to, for example, sputtered light reflected from the chip component body.

In this device, a part of the laser beam scanned by the galvanometer 23 is separated by the beam splitter 27, and the beam B transmitted through the beam splitter 27 is irradiated onto the printing substrate viP as described above. The beam reflected by the beam splinter 27 is focused onto the light receiving surface of the light spot position detection element 29 by the second condenser lens 28, and the position information of the beam spot detected by the light spot position detection element 29 is Based on this, the spot position of the beam B irradiated onto the printed circuit board P is servo-controlled.

With the above optical system, the laser beam B irradiated onto the printed circuit board P is scanned within a rectangular range based on the movable range of the Y-axis rotation mirror 23a and the X-axis rotation mirror 23b of the galvanometer 23, and the beam spot is focused on the printed circuit board. The sputtered light is irradiated onto the solder part of the chip component mounted on the chip component, the sputtered light is received by the light receiving section 13, and an output corresponding to the intensity of the sputtered light is applied to a processing device (not shown), during the inspection of one chip component. Solder flange is detected by integrating the output values output by the light receiving section 13 and comparing them with a certain dark value registered in advance corresponding to the chip component to be inspected.

Note that the method of irradiating a laser beam onto a solder portion and detecting the sputtered light, as in the inspection method of the present invention, is applicable to each solder portion H1 or H2 of the chip component T shown in FIG. 1, for example.
It is also possible to individually test each of the solder parts, but in consideration of misalignment of the chip components, it is preferable to test all the solder parts at once as described above.

〔Effect of the invention〕

According to the present invention, in an automatic mounted printed circuit board inspection device that inspects a printed circuit board by sweeping a beam spot of a laser beam or the like over the printed circuit board to be inspected, all chip components mounted on the printed circuit board to be inspected can be inspected. The beam is irradiated onto the solder parts of the solder part, the sputtered light of the beam is received from all the solder parts, and solder creases are detected based on the amount of light received at the edges, improving the inspection accuracy for solder creases. It is possible to obtain a mounted printed circuit board automatic inspection device.

[Brief explanation of the drawing]

Fig. 1 is a diagram illustrating the solder flange detection method in the automatic inspection device for mounted printed circuit boards of the present invention, Fig. 2 is a diagram illustrating the intensity change of the received sputtering light in the present invention, and Fig. 3 is a diagram illustrating the method of detecting solder flange in the automatic inspection device for mounted printed circuit boards of the present invention. FIG. 4 is a diagram showing the entire mounted printed circuit board automatic inspection apparatus to which the present invention is applied. FIG. 4 is a diagram showing the optical system of the mounted printed circuit board automatic inspection apparatus to which the present invention is applied. P: Printed circuit board to be inspected, T: Chip component, H
...Solder part, B...beam.

Claims (1)

[Claims] A narrowly focused beam is irradiated onto the printed circuit board to be inspected,
In this mounted printed circuit board automatic inspection device that inspects the printed circuit board by detecting the reflected light of the beam from the printed circuit board to be inspected, all of the chip components (T) mounted on the printed circuit board (P) to be inspected are A beam (B) is irradiated onto the solder portion (H) of the solder portion, the reflected light of the beam from all the solder portions is received, and solder flange is detected based on the total amount of received light. Solder flange detection method in automatic inspection equipment for mounted printed circuit boards.