JPS6344282A - Inspecting instrument for appearances of packaged parts - Google Patents

Abstract

PURPOSE:To highly accurately inspect packaged parts by detecting the distance pictures of parts packaged on a printed circuit board and binarizing the detected distance pictures at a threshold level where only the parts can be extracted. CONSTITUTION:A distance picture detector 1 detects the distance pictures of the parts packaged on the printed circuit board. The distance pictures that the detector 1 detects are inputted to a binarization processing part 2, which binarizes said pictures at the threshold level where only the parts can be extracted. A separation and recognition part 3 separates and recognizes the parts from the binarized pictures that the binarization processing part 2 obtains, and a part feature amount calculation part 4 calculates the feature amounts of the separated and recognized parts. A comparison and decision part 6 compares said feature amounts with those of acceptances from an acceptance feature amount storage part 5, and decides whether the parts are accepted or rejected.

Description

Detailed Description of the Invention (Technical Field) The present invention relates to a mounted component appearance inspection device for inspecting the appearance of components mounted on a printed wiring board, and for example, a printed wiring board on which chip components are mounted. It is used to automatically inspect the mounting state of components, soldering state, etc. on a wiring board.

(Background Art) Conventionally, in order to inspect the appearance of components mounted on a printed wiring board, as shown in FIG. 6113(b).
As shown in FIG.
) and lateral slip inspection area (11), and each area (10)
, (11) to measure the deviation of the part (8), and also set a missing part inspection area (12),
The color within the area (12) was measured, and the presence or absence of a missing item was inspected based on the difference in color between the component (8) and the board (7).

However, there are many different soldering conditions, and for example, when there is an insufficient solder area (9A) and an excessive solder area (9B) as shown in FIG. 7(a), the situation shown in FIG. As shown, the soldering is part picture 1 (9A'),
(9B') cannot be binarized accurately, and the part (8B') cannot be binarized accurately.
) There was a problem in that an error occurred in the measurement of the deviation. In addition, as shown in FIG. 8(a), the mounting component (8) has letters (
13) or trimming (14), the same figure (b)
The image shown in ) is obtained, and the image of one solder area (
9゛) and soldering are images other than the parts (13') and (14°
) is confusing and difficult to measure. moreover,
If the board (A) has white silk printed on it, the white board color is exposed like a ceramic board, or the color of the mounted component (8>) is similar to the color of the board (7). It was difficult to measure when there were

(Object of the invention) The present invention has been made in view of the above points, and
The object thereof is to provide a mounted component appearance inspection apparatus that can easily and accurately inspect the component mounting state.

(Disclosure of the Invention) As shown in FIGS. 1 and 2, the mounted component visual inspection apparatus according to the present invention provides a distance image of a component (8) mounted on a printed wiring board (7). The distance image for detection (
an image detector (1), a binary processing unit (2) that binarizes the distance image detected by the detector (1) at a threshold level such that only the component (8) is extracted; The divided chick recognition unit (3) performs the separation recognition of the part (8) from the binary image obtained by the binarization processing unit (2), and the part (8) that has been separated and recognized.
8), a component feature calculation unit (4) that calculates the feature values, a non-defective product feature storage unit (5) that stores the feature values calculated in advance for non-defective products, a component feature calculation unit (4) and the non-defective product characteristics rB. ,
It comprises a comparison/judgment section (6) that compares each characteristic quantity with a quantity storage section (5) to determine whether it is good or bad.

FIG. 2 shows how quadruple images are detected by the distance detector (1). In Figure 2, an optical distance detector 1) based on triangulation is used to determine the height of each point on the board (7) on which the component (8) is mounted as shown in Figure 3 (a). are being measured. Then, the substrate (7) or the distance detector (1) is scanned in the X and Y directions using an X-Y stage or the like to construct a distance image of the substrate (7) on which the components are mounted. From this distance image, the image signal is binarized so that only the shape of part (8) appears white (or black), as shown in Figure 3 (
A binarized image as shown in b) is obtained. Using this binarized image, each component image (8°) is recognized separately and labeled.

An example of the labeled state is shown in FIG. 3(c).

Then, for each labeled land (white or black mass with connectivity), as shown in FIG. 4, feature quantities such as the center of gravity, surface area, circumscribed rectangle, direction of the principal axis of inertia, etc. are calculated.

Then, a comparison is made with the feature amount of the non-defective board calculated in advance.

The specific flow of the inspection will be explained with reference to the flowcharts in FIGS. 5(,) to (c). First, as shown in Figure 5(a), a distance image of a board on which components are mounted is input, the input image signal is binarized, and each land in the binary image is labeled and separated. After recognition and area filtering, the feature value calculation for each land is performed. Once the feature value calculation is completed, all distances between the center of gravity of the labeled land and the center of gravity of the non-defective land are calculated. Inspection land (n) and non-defective land The center-of-gravity distance fiRnm with (Sho) is determined by the following formula.

Rn+a=y' (Xng-Xmg)2±(Yng
(Xng, Yng) are the coordinates of the center of gravity of the inspection land (n), (X Iag, Y Ia
g) is the coordinate of the center of gravity of the non-defective land (m).

Next, as shown in FIG. 5(b), if the center of gravity distance Rnm is within a predetermined standard, it is stored as a candidate corresponding to a good product, and if there is no candidate, it is determined that the product is missing. do.

If there is one inspection land (n) corresponding to a non-defective land (,,), a label is associated with the non-defective land, and if there are multiple inspection lands, an evaluation function α11111 of the following equation is calculated.

a nm=J (Rnm −Rn+can)2+ (
Am - An) 2/ , Am where An is the area of the inspection land (n>), A... is the area of the non-defective land (m>), and Rmcan is expressed by the following formula.

Rn+ean -Σ (win Rnm')/
In the above formula, Rnm' is the distance within the standard,
Σ(+ain Rnm') is the sum of the minimum values.

Further, K is the number of non-defective products that are correlated 1:1 in terms of distance.

For items whose αnun is within the standard, labels are associated with non-defective items, and those in the pond are determined to be contaminated with foreign matter.9 Using this method, even if the positioning accuracy of the board at the time of inspection is rough, the judgment can be made. This makes it possible to eliminate the need for complicated processing. As a simpler expression of the evaluation function, the following expression may be used for calculation.

a nm' = (Rnm - Rmean) + An/
Am Next, regarding the associated lands, the fifth (
As shown in 2I(c), the area is compared and An>Am
In the case of A n CA +n, it is determined to be "wrong part" or "bridge", and in the case of A n CA +n, it is determined to be "part standing" or part missing. If they are approximately equal, the circumscribing rectangle is examined. If the circumscribed rectangle is not within a preset range, it is determined that there is a "component misalignment °'." Next, looking at the direction of the principal axis of inertia, if the conditions such as 0 area, circumscribed rectangle, direction of principal axis of inertia, etc. for determining the presence or absence of parts are consistent with a non-defective product, it is determined to be a non-defective product.

(Effects of the Invention) As described above, in the present invention, a distance image of a component mounted on a printed wiring board is detected, and the detected distance image is divided at a threshold level such that only the component is extracted. Because it is converted into a value, the accurate part shape can be taken, and inspection can be performed with high precision without being affected by the color or shape of the part or the condition of the board. Since the parts are compared with non-defective parts using 52N, even if the board is roughly positioned during inspection, it will not be affected by the detection of parts displacement, etc., and it can be detected with high accuracy. There is an effect that it can be done.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the basic configuration of the present invention, FIG. 2 is a perspective view showing a distance image detector used in the above, and FIG.
) to (c) are explanatory diagrams of the same operation as above, FIG. 4 is an explanatory diagram to explain the features of the mounted components used in the same, and FIG. Flowcharts showing operations, FIGS. 6(a) to (C), FIGS. 7(a)(b)
) and FIGS. 8(a) and 8(b) are explanatory diagrams for explaining the conventional inspection method. (1) is a distance image detector, (2) is a binarization processing unit, (3
) is the separation recognition unit, (4) is the component feature value calculation unit, (5) is the non-defective feature value storage unit, 6) is the comparison determination unit, (7) is the board, and (8) is the component.

Claims (1)

[Claims] (1) A distance image detector for detecting a distance image of a component mounted on a printed wiring board, and a distance image detected by the detector that is divided at a threshold level such that only the component is extracted. A binarization processing unit that converts into values, a separation recognition unit that separates and recognizes parts from the binarized image obtained by the binarization processing unit, and component features that calculate features of separated and recognized parts. A calculation unit, a non-defective feature storage unit that holds feature quantities calculated in advance for non-defective products, and a comparison judgment unit that compares the feature quantities of the component feature calculation unit and the non-defective feature storage unit to determine quality. A mounted component appearance inspection device comprising: