JPH0682383A - Inspection device for mounted printed circuit board - Google Patents

Abstract

PURPOSE:To obtain the inspection device shortening an inspection time by using two sensors to allow them to scan at the same time. CONSTITUTION:Unit inspection devices 13, 14, 15, 16 are arranged on the same circumference of a circle at equal intervals with respect to the center of a rotary member 12 so as to successively scan mounted printed circuit boards 10, 10'. The mounted printed circuit boards 10, 10' are moved in the direction shown by an arrow A by the distance predetermined by a printed circuit board feed device in synchronous relation to the pulse output of an angle-of-rotation detector detecting the angle of rotation of the rotary member 12. By this constitution, the whole of the mounted printed circuit boards can be scanned.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for inspecting a printed circuit board that has been mounted, and in particular, it uses a beam spot that has been finely squeezed to inspect for misalignment, missing items, soldering defects, solder bridges and the like. Is what you are trying to do.

[0002]

2. Description of the Related Art Conventionally, as a device for automatically inspecting a mounted printed circuit board for misalignment, missing parts, defective soldering, solder bridge, and the like, there is a device which uses a rotating body and utilizes reflection of a beam spot.

A description will be given below with reference to the drawings. Figure 4
FIG. 4 is a perspective view showing an example of a conventional mounted printed circuit board inspection apparatus. In FIG. 4, reference numeral 12 denotes a rotationally driven rotating body, which is located on the same circumference of the rotating body.
Reference numerals 15 and 16 denote unit inspection devices that respectively irradiate a beam spot and receive a plurality of reflected lights. 19 is irradiation light and 20 is reflected light. Reference numeral 17 denotes a scanning locus in the present illustrated state in which the unit inspection device 16 scans, and 18 denotes a locus scanned by the next unit scanning device 13. Reference numeral 10 denotes a mounted printed circuit board to be inspected, which is moving in the direction of arrow A.

The operation of the inspection position of the mounted printed circuit board having the above structure will be described below. A plurality of unit inspection devices 13 to 16 composed of a plurality of beam spot generating means located on the same circumference of the rotationally driven rotating body 12 and a plurality of light receiving elements for receiving the reflected light of the beam spot from the mounted printed circuit board. One is the rotating body 12
The unevenness of the mounted printed circuit board 10 is inspected with the rotation of. A means for moving the mounted printed circuit board each time the one unit inspection device scans and passes the mounted printed circuit board 10 advances in the direction of arrow A having a constant width,
Prepare for inspection at the next unit inspection device. The mounted printed circuit board is inspected by repeating the above operation.

[0005]

With the above-described structure, while one unit inspection device scans the mounted printed circuit board, the unit inspection device such as the facing surface (180 ° symmetry direction) is not used. Not not. Therefore, the inspection device and the inspection time are wasteful in space and time.

In view of the above points, an object of the present invention is to save the inspection device and inspection time in terms of space and time.

[0007]

SUMMARY OF THE INVENTION The present invention comprises means for moving two or more independent mounted printed circuit boards to be inspected relative to a rotationally driven rotating body, and said rotating body. Positioned on the same circumference centered on the center of rotation, each of the mounted printed boards is irradiated with a beam spot from a direction substantially perpendicular thereto, and the beam spot has two or more beam spots as the rotor rotates. And a means for simultaneously inspecting one mounted printed circuit board at each location.

[0008]

According to the present invention, the mounted printed circuit boards can be simultaneously inspected at symmetrical positions or arbitrary positions of the rotationally driven rotating body.
The inspection time per sheet can be reduced. In order to reduce the inspection time by the usual method, a plurality of inspection apparatuses are required, but in the present invention, it is possible to realize the same effect as the plurality of inspection apparatuses at a lower cost in a narrower space. .

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An inspection apparatus for a mounted printed circuit board according to an embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a perspective view of a unit inspection device in which an optical system for projecting a beam spot and an optical system group for receiving light are integrated in one embodiment of the present invention.

Reference numeral 1 denotes, for example, an optical system for projecting a beam spot using a laser, and reference numerals 2, 4, 6, 8 receive reflected light from the reflecting surface of the beam spot, and display height and brightness information of the reflecting surface. The light receiving optical system is a photoelectric conversion element such as a semiconductor detection element (PSD) for obtaining. This PSD
Has a certain predetermined length, and the outputs of a plurality of output terminals relatively change according to the irradiation position of the beam spot. For this, a CCD (charge coupled device) line sensor or the like may be used. It is possible. Reference numerals 3, 5, 7, and 9 are lenses (or lens groups) for imaging the reflected beam spots from the mounted printed circuit board on the photoelectric conversion elements 2, 4, 6, and 8 to perform triangulation. is there. These photoelectric conversion elements and lenses are arranged around the optical axis of the beam spot 11, and in the present embodiment, they are arranged at equal intervals on the same circumference centered on the four beam spots. Reference numeral 10 denotes a mounted printed circuit board, and the beam spot 11 is irradiated substantially perpendicular to the mounted printed circuit board 10.
In this embodiment, two mounted printed circuit boards are inspected at the same time, but there is no problem even if the number is greater than that.

FIG. 2 is a perspective view of the whole inspection apparatus according to one embodiment of the present invention. In FIG. 2, 13, 14, 15, and 16 are one unit inspection device in which the optical system groups for projecting and receiving light shown in FIG. 1 are integrated, and 12 is a drive source (not shown) such as a motor. The rotating body (disc), which is rotationally driven at a constant speed, has the unit inspection devices 13, 14, 15, and 16 that rotate with the rotating body 12 at equal intervals on the same circumference with respect to the center of the rotating body 12. The two beam spots are sequentially mounted on the two printed circuit boards 10 and 10 '.
Are positioned to scan.

The mounted printed circuit boards 10 and 10 'are synchronized with the pulse output of the rotation angle detecting device for detecting the rotation angle of the rotating body 12 and are separated by a predetermined distance by a printed circuit board feeding device having a structure described later. It is sequentially moved in the direction of arrow A. As a result, it becomes possible to scan the entire mounted printed circuit boards 10, 10 'with the beam spots 11, 11'. Reference numerals 17 and 17 'indicate the loci of scanning by the unit inspection devices 14 and 16 at present, and 18 and 18' indicate trajectories of the next unit inspection devices 15 and 13.

In FIG. 2, when the unit inspection devices 14 and 16 have completed scanning, the mounted printed circuit boards 10 and 10 'are moved in the direction A and the movement is completed before the next unit inspection devices 13 and 15 start scanning. As a result, the inspection can be completed in the minimum time.

FIG. 3 is a block diagram of an electric circuit of the inspection apparatus of the present embodiment, in which two current outputs whose values relatively change depending on the irradiation position from the photoelectric conversion element are calculated to calculate height information and luminance information. Is what you get. In FIG. 3, 31 indicates height information obtained from two current outputs of the photoelectric conversion element 2 through a divider 52, and luminance information obtained through an operational amplifier 53 from the sum of the two current values. This is an information detection circuit. 32, 33 and 34 are also similar to the height and brightness information detection circuit 31 and are connected to the photoelectric conversion elements 4, 6 and 8. In this case, since four photoelectric conversion elements are used, four pieces of height and luminance information are also output for one light spot.

Reference numeral 35 is a height information selection circuit for obtaining one height information from four pieces of height information.
There is a method of taking the average of the remaining two excluding the maximum level and the minimum level. 36, like 35, is a brightness information selection circuit for obtaining one brightness information from four brightness information,
As a selection method, for example, there is a method of taking the maximum level among the four. The two height and luminance information selection circuits 35 and 36
CPU by saving RAM37 and adding pre-processing
It was made for the purpose of reducing the load of 38.

The above-mentioned two height and luminance information selection circuits 3
The outputs of 5 and 36 are RA connected to the bus of CPU38.
It is sent to M37. The CPU 38 compares the height information and the luminance information read from the RAM 37 with the height information and the luminance information stored in advance that is obtained from the mounted printed circuit board serving as a reference and compares the height information and the luminance information. Determine the quality of the printed circuit board.

This embodiment as described above has a plurality of inspection targets.
Beam spots 11 and 11 'are vertically irradiated onto the mounted printed circuit boards 10 and 10' (two in the drawing), and a plurality of photoelectric conversion elements 2, 4, 6 arranged around the beam spots.
Since the change in height and brightness of each point of the mounted printed circuit board is measured while moving together with 8, each point of the mounted printed circuit board is measured under the same conditions, and a good inspection can be performed.

Further, since the reflected light from the mounted printed circuit board is configured to be received by the plurality of photoelectric conversion elements arranged around the beam spot, the reflected light from the mounted printed circuit board is of various kinds. Even if the diffusion characteristic is obtained, the variation of the inspection result due to the diffusion characteristic can be reduced.

Further, for scanning the mounted printed circuit boards 10, 10 'of the beam spots 11, 11', the output pulse from the rotation angle detection device connected to the rotating body 12 is sent to the printed circuit board feeding device (not shown). Do by typing. That is, since the mounted printed circuit boards 10 and 10 'are accurately moved by the printed circuit board feeding device in synchronization with the rotation angle of the rotating body 12, the scanning position on the mounted printed circuit board can be accurately determined.

In the embodiment, both the height and the brightness on the mounted printed circuit board are detected. However, when the inspection accuracy may be low, only one of them is inspected. It is a good thing to do.

[0022]

As described above, the mounted printed circuit board inspecting apparatus of the present invention irradiates the mounted printed circuit board with a beam spot from the projection optical system almost vertically, and a plurality of beam spots are provided around the optical axis. By arranging the light receiving optical system and scanning them while measuring them on multiple mounted printed circuit boards as one unit, it is possible to save the inspection device space which was difficult with the conventional inspection device. The inspection time can be shortened.

[Brief description of drawings]

FIG. 1 is a perspective view of an inspection apparatus in which an optical system for projecting a beam spot and an optical system group for receiving light are integrated in one embodiment of the present invention.

FIG. 2 is a perspective view showing an entire inspection device according to an embodiment of the present invention.

FIG. 3 is a block diagram of an electric circuit of the inspection apparatus of this embodiment.

FIG. 4 is a perspective view showing an example of a conventional mounted printed circuit board inspection apparatus.

[Explanation of symbols]

1 ... Optical system for projecting beam spot, 2, 4, 6, 8 ...
Photoelectric conversion element, 3, 5, 7, 9 ... Lens or lens group, 10, 10 '... Mounted printed circuit board, 11, 11'
… Beam spot, 12… Rotating body, 13, 14, 15, 16…
Unit inspection device.

Claims (1)

[Claims] 1. A means for moving two or more independent mounted printed circuit boards to be inspected relative to a rotationally driven rotating body, and a same circle having a center of rotation of the rotating body as a center. Beam spots are located on the circumference of the mounting printed circuit board and are radiated in a direction perpendicular to the mounted printed circuit board.
And a means for simultaneously inspecting one mounted printed circuit board at one or more points, respectively.