JPH02187606A - Inspection device for mounted printed board - Google Patents

Abstract

PURPOSE:To satisfactorily check the solder surface after the soldering process by arranging plural light receiving optical systems around the optical axis of an irradiating light thrown to a printed board and scanning a light throwing optical system and light receiving optical systems as one body on the mounted printed board while measuring. CONSTITUTION:A mounted printed board 38 is approximately vertically irradiated by the light from a beam spot light throwing optical system 1, and the reflected light is received by a light receiving optical system group including plural photoelectric conversion elements 2 to 13 arranged around the light throwing optical system 1 in an approximately concentric circle. Filters 26 to 37 and lenses 14 to 25 are provided on rotating body as one body so that brightness information of light having a specific wavelength out of the reflected light from the printed board 38 is made incident on the photoelectric conversion elements 2 to 13. The printed board 38 is moved relatively to this rotating body to detect the ruggedness and the brightness distribution of the mounted printed board 38, and further, parts, solder, lands, resists, etc., on the board are identified by color in accordance with brightness information of light having the specific wavelength.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an inspection device for mounted printed circuit boards, and in particular uses a narrow beam spot to detect misalignment of mounted components, solder defects, solder bridges, etc. It is intended to examine the

Conventional technology Conventionally, misalignment of components on mounted printed circuit boards, missing parts, etc.
As a device for automatically inspecting solder defects, solder bridges, etc., there is a method using a multi-slit light and a camera.

This will be explained below with reference to the drawings. In Figure 6,
55 and 56 are irradiation devices that irradiate slit light, 54 is a camera, and 67 is a mounted printed circuit board. By irradiating the mounted printed circuit board 57 with two slit lights obliquely from above so that their respective optical axes are perpendicular to each other and observing it with the upward camera 54, the height of the mounted component can be measured using the principle of triangulation. Also, at this time, by alternately irradiating with the multi-slit irradiation devices 55 and 56,
The position of the parts in the X and 7 directions (see Figure 6) can be known.

Problems to be Solved by the Invention However, with the above configuration, although it is possible to measure the position of the mounted component before soldering, it is difficult to accurately inspect the solder surface after the soldering process. This is because the solder surface is close to a mirror surface, so depending on the orientation of the solder surface and the position of the camera, the reflected light may be too strong and saturate the camera, or conversely, the reflected light may be too weak to be detected. This is because

Means for Solving the Problems Rotation 1 A rotary body driven by rotation 1, a means for moving a printed circuit board to be inspected relative to the rotary body, and a substantially concave circle centered on the center of rotation of the rotary body. Located on the circumference,
a plurality of beam spot generating means disposed on the rotating body so that each beam spot is irradiated with a beam spot from a direction substantially perpendicular to the printed circuit board, and the beam spot sequentially scans the printed circuit board as the rotating body rotates; , a plurality of wavelength separations arranged radially on the rotary body around each of the beam spots, and for separating and passing light of different wavelengths from the reflected light of the beam spores from the printed circuit board, respectively; a means for receiving the separated reflected light of each wavelength, an output corresponding to the receiving position, that is, an output corresponding to the distance, and a received light energy of each wavelength light obtained by the specific wavelength separating means, that is, 1. An inspection device for a mounted printed circuit board, comprising a plurality of photoelectric conversion means for outputting height and luminance information for each wavelength, which outputs an amount corresponding to brightness.

Effect The reason for the above structure is that a plurality of photoelectric conversion elements that receive reflected light from the beam spot are arranged around the beam spot, so even if the reflected light changes depending on the orientation of the solder surface, it is not possible to respond accordingly. The reflected light can be received, and the unevenness and brightness distribution of the mounted printed circuit board can be known from it, and by comparing with the correct information of the unevenness of the front printed circuit board that is known in advance, the mounted printed circuit board can be detected. It is possible to inspect the board. Furthermore, by obtaining information on the brightness of light at a specific wavelength, color information can be obtained, making it possible to identify components, solder, lands, resists, etc. on mounted printed circuit boards by color. Furthermore, inspection accuracy can be improved.

Embodiment Hereinafter, a mounted printed circuit board inspection apparatus according to an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a perspective view of a unit inspection device in which a beam spot projecting optical system and a light receiving optical system group are integrated. 1 is
For example, an optical system for projecting a beam spot using white light, 2
6.29.32.35 is a filter that allows only the R light to pass among the beam spot reflected light; 27.30, 33.
36 is a filter that allows only G light to pass; 28, 31,
34° and 37 are filters that allow only B light to pass through.

2 to 13 are semiconductor device detection elements for receiving the light of each specific wavelength that has passed through the filter out of the reflected light from the reflecting surface of the beam spot, and obtaining information on the height and brightness of the reflecting surface; This is a 7-Heno photoelectric conversion element. As this photoelectric conversion element, PSD
In other words, we use a device that has a certain predetermined length and that outputs from multiple output terminals change relatively depending on the irradiation position of the beam spot, but it is also possible to use a CCD line sensor etc. It is. As a result, it is possible to obtain not only the brightness information of R, G, and B obtained by the photoelectric conversion element, but also the color information of that point. Separation of foil parts can be performed well. Reference numerals 14 to 25 designate lenses or lens groups that form images on the photoelectric conversion elements 2 to 13, respectively, on the reflected beam spots from the mounted printed circuit boards in order to perform triangulation. These photoelectric conversion elements and lenses are arranged at equal intervals on the same circumference centered on the optical axis of the beam spot. 3s is a mounted printed circuit board, and 39 is a beam spot that is irradiated almost perpendicularly to the mounted printed circuit board 38.

FIG. 2 is a perspective view of the entire inspection device. 41 to 44 are
This is a unit inspection device in which the optical system group shown in FIG. 1 is integrated. 40 is driven by a drive source (not shown) such as a motor.
It is a rotating disk that is driven one rotation at a nearly constant speed. The unit inspection devices 41 to 44 are arranged so that the beam spots sequentially scan the mounted printed circuit board 38 as the rotating disk 40 rotates at equal intervals on the same circumference with respect to the center of the rotating disk 40. There is. Therefore, the mounted printed circuit board 38 is shown in FIG. By sequentially moving in the y direction of the z coordinate system, it becomes possible to scan the entire mounted printed circuit board 38 with the beam spot. 45
is the trajectory currently being scanned by the unit inspection device 43, and 4
6 indicates the locus scanned by the unit inspection device 42 immediately before. This allows the inspection to be completed in the minimum amount of time without wasting time.

FIG. 3 shows an electric circuit of the present device which calculates two current outputs whose values change relatively depending on the irradiation position from the photoelectric conversion element to obtain height and brightness information. Reference numeral 67 indicates an electric circuit for R wavelength light, which will be explained below. 59 is 2 of photoelectric conversion element 2
Height information is obtained from the two current outputs through the division brightness 67,
Further, it is a height and brightness information detection circuit which obtains brightness information from the sum of the two current outputs through an operational amplifier 68. 60, 61, 62 are also detection circuits similar to the height and brightness information/detection circuit b9, and the photoelectric conversion elements 5, 8.
11. In this case, since four photoelectric conversion elements are used for one wavelength of light, four pieces of height and brightness information are output for one light spot. 63 is a height information selection circuit that obtains one piece of height information from four pieces of height information, and the selection method is, for example, to remove the maximum level and minimum level of the four pieces of height information and collect the average of the remaining two. There is a way to do it. Reference numeral 64 indicates a brightness information selection time for obtaining one brightness information from four pieces of brightness information, and a selection method includes, for example, a method of taking the maximum level among the four pieces of brightness information. In this way, selection times '1''('(G 3, (34 is RAM
C P 'U by adding 66 savings and preprocessing
This was provided for the purpose of reducing the load on the e6. 6
8 is an electric circuit 10]\-2 for G wavelength light, and its configuration is similar to 67. Reference numeral 69 denotes an electric circuit for B wavelength light, which has a similar configuration. The three sets of electric circuits 6
The output from 7.68.69 is sent to the RAMes connected to the CPU 66 bus. The CPσ66 compares the height and brightness information read out from the RAM 65 with the height and brightness information that has been obtained and stored in advance from the mounted printed circuit board serving as a reference, and determines the mounted printed circuit board to be inspected. Determine the quality of the board.

FIG. 4 is a perspective view of another embodiment of a unit inspection device in which a beam spot projecting optical system and a light receiving optical system are integrated. 71 is an optical system for projecting a beam spot using, for example, a laser, and 72, 73, 74, 75 is a device for receiving the reflected light from the reflecting surface of the beam spot and obtaining information on the height and brightness of the reflecting surface. It is like a semiconductor device detection device PSD or CCD line sensor. 76, 7, 78, 79, in order to perform triangulation, the reflected light from the mounted printed circuit board is converted into the photoelectric conversion element 2.
．． 73. 74. 76 It 11 To - 2 It is the lens or lens group that is used to form an image.

These photoelectric conversion elements and lens groups are
In this embodiment, 4 m long beams are arranged around the optical axis of 1, and are arranged at equal intervals on the same circumference with the beam spot as the center. Among the unit inspection apparatuses having such a configuration, those having laser wavelengths of R wavelength, G wavelength, and B wavelength are prepared.

FIG. 6 is a perspective view of the entire inspection apparatus of the second embodiment. 81, 84, 87.90 are the unit inspection devices using an R wavelength laser; 82, 85; 88.91 are the unit inspection devices using a G wavelength laser; 83.86.
89.92 is the unit inspection device using a B wavelength laser. 8° is a drive source such as a motor (not shown)
The yoshi is a rotating disk that is driven to rotate at a nearly constant speed.

The unit inspection devices 81 to 92 are arranged on the same circumference with respect to the center of rotation of the rotating disk 8o, with each set of lasers of R, G, and B wavelength being arranged at equal intervals.
The R, G, and H beam spots are arranged so as to sequentially scan the same locus on the mounted printed circuit board 38 as the board rotates.

Therefore, the mounted printed circuit board 38 is shown in FIG. 5! ,
7. The entire mounted printed circuit board 38 is scanned by each beam spot of RlG and B by intermittently sequentially moving and assisting in the y direction of the Z coordinate system each time the scanning of one set of unit inspection devices is completed. It becomes possible to do so. 93 is the trajectory currently being scanned by the unit inspection devices 87, 88, 89,
Reference numeral 94 indicates the trajectory scanned by the unit inspection devices 84, 85, and 86 immediately before. That is, three types of unit inspection devices using R, G, and B wavelength lasers can scan the same inspection point and obtain height and brightness information for each specific wavelength.

The electric circuit for obtaining height and brightness information by calculating two current outputs whose values change relatively depending on the irradiation position from the photoelectric conversion element of the second embodiment is the same as that of the first embodiment. The explanation will be omitted.

Effects of the Invention As described above, according to the present invention, a beam spot is irradiated almost perpendicularly to a mounted printed circuit board, and a plurality of light receiving optical systems are arranged around the optical axis of the printed circuit board. The irradiation and light reception optical systems work together to measure and scan the mounted printed circuit board, and obtain height information, brightness information,
Obtaining color information has made it possible to better inspect solder surfaces, which was difficult to do with conventional inspection machines.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a single unit inspection device in which a white beam spot projecting optical system and a light receiving optical system are integrated in one embodiment of the mounted printed circuit board inspection device of the present invention, and FIG. 2 is the same embodiment. 3 is a block diagram of the electric circuit of the same embodiment, FIG. 4 is a perspective view of the unit inspection device of the second embodiment, and FIG. 6 is a perspective view of the main part of the same embodiment. FIG. 6 is a perspective view of a conventional printed circuit board inspection device. 1.71...Optical system for beam spot projection, 2
~13.72~75...Photoelectric conversion element, 14~
25°76~79...Lens, 26~37...
... Filter group for passing specific wavelength, 38 ...
- Printed circuit board to be inspected, 39...Beam spot, 40.80...Times 14\7 Rotating disk, 41-44.81-92...Unit inspection device, 54 ...Camera, 55.56...
・Irradiation device for slit light projection, 59, 60, 61.62
...Height and brightness detection circuit, 63...
Height information selection circuit, 64...Brightness information selection circuit, 65...RAM, ee...C20

Claims (2)

[Claims] (1) A rotary body that is driven to rotate, a means for moving a printed circuit board to be inspected relative to the rotary body, and a means for moving a printed circuit board to be inspected relative to the rotary body, located on substantially the same circumference around the center of rotation of the rotary body, a plurality of beam spot generating means disposed on the rotating body so that each beam spot is irradiated with a beam spot from a direction substantially perpendicular to the printed circuit board, and the beam spot sequentially scans the printed circuit board as the rotating body rotates; , a plurality of specific wavelength separation means arranged radially on the rotating body around each of the beam spots, and for separating and passing light of a plurality of different wavelengths from the light reflected from the beam spot from the printed circuit board; , receives the reflected light of each wavelength separated by the specific wavelength separation means, and outputs according to the receiving position;
A mounted printed circuit board inspection device characterized by comprising a plurality of photoelectric conversion means that output an amount corresponding to received light energy. (2) a rotary body that is rotationally driven; a means for moving a printed circuit board to be inspected relative to the rotary body; A plurality of sets of beams having different wavelengths are arranged on the rotating body so that each beam spot is irradiated from a direction substantially perpendicular to the printed circuit board, and the beam spot sequentially scans the printed circuit board as the rotating body rotates. a plurality of beam spot generating means for generating beams; and a plurality of beam spot generating means arranged radially on the rotary body with each of the beam spots as a center, receiving each reflected light of the beam spot from the printed circuit board, and moving the beam spot to the light receiving position. 1. An inspection device for a mounted printed circuit board, comprising a plurality of photoelectric conversion means that output an output corresponding to the received light energy and an amount corresponding to the received light energy.