JPH0261505A - Method for inspecting component part - Google Patents

Abstract

PURPOSE:To inspect whether a part is present with high reliability by comparing a set value, which is obtained by applying statistical processing to two kinds of brightness histograms at every part of a sample substrate, with a value obtained by applying statistical processing to two kinds of brightness histograms at every part of a substrate to be inspected. CONSTITUTION:In the first process, each of the parts of a plurality of substrates to be inspected is used as a standard object to be inspected and the brightness histogram of a range where the shade of the part is formed by an illumination device and the brightness histogram of a range where no shade of the part is formed are calculated. In the second process, the respective brightness histograms are subjected to statistical processing to calculate characteristic quantities. In the third process, these characteristic quantities are subjected to statistical processing at every part to obtain a value which is, in turn, used as a set value for judging whether the shade of the part is present. In the fource process, the brightness histogram of a range where the shade of each part of each substrate to be inspected is formed and that of a range where no shade of the part is formed are calculated. In the fifth process, the respective brightness histograms calculated in the fourth process are subjected to statistical processing to calculate characteristic quantities and, in the sixth process, the characteristic quantity of each part to be inspected is compared with the set value of each part calculated in the third process at every part to judge the presence of shade. In the seventh process, the presence of the part is judged from the presence of the shade.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a component inspection method for determining whether a component to be inspected is present at a specific position in an inspection step during a manufacturing process.

BACKGROUND OF THE INVENTION Conventionally, as a method of this kind, as shown in FIG.
A lighting device 3 is installed diagonally above the part to be inspected 2 above,
A shadow 4 of the component 2 is created by illuminating the component 2, a histogram area for obtaining a luminance histogram is set in the range where the shadow 4 is formed, and a lighting device 6 is placed at a position facing the lighting device 3 across the component 2. , and illuminate the component 2 to create a shadow 6 of the component 2 in the direction opposite to the shadow 4. Set the histogram area for obtaining the brightness histogram in the range where this shadow 6 is created, and set it directly above the component 2. There is a component inspection method in which the presence of the component to be inspected is inspected based on the difference between two types of histograms obtained when the images are captured by the image recognition device 8 through the TV camera 7 and these two histogram regions are illuminated with the respective lights mentioned above. .

Problems to be Solved by the Invention However, in the above method, the color of the test board, the condition of its surface, etc., and the shape (size, height) of each component
Since the histogram varies greatly depending on the position of the part, it is difficult to set the parameters, and it takes a long time to set them. Therefore, since parameters were set based on experience and feeling, the set values varied depending on the person, making it impossible to perform stable inspections.

Means for Solving the Problems Therefore, in the component inspection method of the present invention, each component of a plurality of substrates to be inspected is illuminated by a lighting device installed diagonally above the component to be inspected as a pre-inspection step. A first step of calculating a brightness histogram of a range where a shadow occurs and a brightness histogram of a range where a shadow does not occur of the part;
In the second step, the brightness histograms for each component of each board obtained in the first step were statistically processed to obtain the characteristic quantities, and in the second step, the characteristic quantities of each component of each board obtained in the second step were statistically processed for each component. The third value is the setting value for determining the presence or absence of a shadow on the part.
This is a component inspection method that includes pre-processing up to the process.

Function The present invention compares a setting value obtained by statistically processing two types of brightness histograms obtained in advance for each component of a plurality of sample boards with a value obtained by statistically processing two types of brightness histograms for each component of a test board. , when there are variations in the reflection state depending on the material of the background of the inspected part, when the shadow of the inspected part becomes weak due to reflected light from other inspected parts near the inspected part, and when the background is made of a material that is difficult to reflect. Even when it is difficult to find a difference between the image and the shadow, the influence of variations in each part is taken into account, and it is easy to determine the setting value for determining the presence or absence of a part, and this setting value is numerically supported. This enables highly reliable parts presence inspection.

EXAMPLE An example of the present invention will be described below. 1 and 2 are flowcharts of a component inspection method in an embodiment of the present invention,
FIG. 3a is a diagram showing the histogram area 9°10 when the shadow 6 of the component 2 is created by the illumination device 5, and FIG. 3 is a graph AI2 (!: The characteristic trace value aA12, FIG. 3C is the graph B12 of the brightness histogram of the histogram area 1o in FIG. A diagram showing the histogram area 9.1o of FIG. 3 eil-i, a graph C12 of the brightness histogram of the histogram area 9 of FIG.
The graph DI2 of the brightness histogram in U area 10 and the value αD12 of the characteristic quantity, Figure 4a is the graph aA of the characteristic quantity in Figure 3.
1 and set value βA1, Figure 4 is the graph of the characteristic quantity αB1 and set value βB1 of Figure 3C, Figure 4C is the graph of the characteristic quantity αc1 and set value βc1 of Figure 3 e, Figure 4 d is a graph of the characteristic quantity αD1 and the set value βD1 in FIG. 3f.

The component inspection apparatus of this embodiment inspects the presence or absence of the component 2 mounted on the circuit board 1 shown in FIG. 5, and uses the component inspection method of the present invention as is. Part 2 which is the object to be inspected
The positional relationship between the lighting bags 6, 3, 6, and the TV camera 7 for capturing the brightness histogram is shown in Figure 6. The substrate 1 is moved in parallel by a robot.

Now, the operation of the component inspection apparatus of the embodiment will be explained based on FIGS. 1 and 2. In step 1 (preparation for inspection), the illumination device 3 emits light for each component 2 of a plurality of sample boards to create a shadow 4 of the component 2, and the third histogram area 9p1oc
), the brightness histogram AI2. Take in B12. Similarly, other parts (n=1.2...
2 However, for n: part number, 2: number of parts), the brightness histogram A B (n=1, 2, -・
”n, where n2+n2+n: part number, 22 parts number), and in the same way, brightness histograms Ank, Bn for each part of the other boards.
k (n = 1, 2... 2. = 1, 2°...
...q However, n: part number 2°C: number of parts, ni: board number, q: number of boards) are taken in. In step 2, the illumination 5 is emitted in exactly the same manner as in step 1, and each substrate (k=1...
2. ....q, where: board number, q: number of boards) shadow of each part (n = 1.2..., where n: part number, 2: number of parts) 6 and brightness histogram Cn in histogram area 9.10 (FIG. 3).
k, take in Dnk. In step 3, each brightness histogram Ank, B for each component of each board obtained in steps 1 and 2 is
nk, Cnk, Dnk (Example: Al1.B121 in Figure 3)
CI2. D12 ) is statistically processed (Table 1) to obtain the characteristic quantity α
Ank'αBnk, αcnk.

aDnk (Example: ('A12pαB12+αC in Figure 3)
12*αD12).

In step 4 of Table 1, the characteristic quantities αA n k, αBnk, ``Cnk, and aDnk of each board component obtained in step 3 are statistically processed for each component (Table 1) to determine the presence or absence of a shadow of the component. The set values βAn'βBn, βcn, βDn (βA1+βB1.βc1.βD1 in the side temperature diagram 4) are determined.

In step 6, each component (
n=1.2. 2) The illumination device 3 emits light to create a shadow 4 of the component, and histogram areas 9, 1
Brightness histogram E1. Take in G1. Similarly, brightness histograms En, Fn for other parts
take in. In step 6, in the same manner as in step 5, the illumination device 5 is turned on to emit light in an actual inspection to create a shadow 6 of each component on the inspection board, and brightness histograms Gn and Hn are captured in the histogram areas 9 and 1o. Step 7
Now, the luminance histograms obtained in steps 5 and 6 are statistically processed (Table 1) to obtain the characteristic quantities γEn'+γFn and γGn.

Find γHn. In step 8, each brightness histogram En for each component of the actual test board obtained in step 7,
The characteristic quantities γEn+γFn, γGn, γHn obtained by statistical processing of Fn, Gn, and Hn (Table 1) are compared with the setting values βAn+βBn+βcn and βDn obtained in step 4, and the presence or absence of a shadow is determined in step 9.

(Example βCn-βAn≦γGn-γEn and βBn-β
When Dn×γFn−γHn holds true, it is determined that a shadow is formed, and when either one does not hold, it is determined that a shadow is not formed. ) In step 10, the presence or absence of the part is determined based on the presence or absence of the shadow determined in step 9.

In addition, it is more effective to install two lighting devices in the parts inspection device (Fig. 5) in a position that illuminates the parts diagonally from above on a line connecting the lighting devices 8 and 9, and inspect the parts with four lights. be.

Effects of the Invention As described above, according to the present invention, setting values obtained by statistically processing two types of brightness histograms obtained in advance for each component of a plurality of sample boards, and two types of brightness histograms for each component of a test board are calculated. Since the values are compared with statistically processed values, the influence of variations in each part is also taken into account, and it is easy to determine the set value for determining the presence or absence of parts, and this set value has numerical support. This makes it possible to perform highly reliable component presence inspections.

[Brief explanation of the drawing]

Fig. 1.2 is a flowchart of a component inspection method according to an embodiment of the present invention, Fig. 3a is a diagram showing a histogram area when a shadow of a part is created by an illumination device, and Fig. 3 is a diagram of a histogram area. A diagram of the relationship between the brightness histogram graph and the value of the special quantity, FIG. 3C is a diagram of the relationship between the graph of the brightness histogram of the histogram area of FIG.
Figure 3 d is a diagram showing the histogram area when a shadow of a part is created by the illumination device, Figure 3 e is a diagram showing the relationship between the luminance histogram graph of the Hiftogerum area in Figure 3 d and the value of the characteristic quantity, Figure 3 f is a diagram of the relationship between the luminance histogram graph of the histogram area in Figure 3 d and the value of the characteristic quantity, and Figure 4
Figure a is a diagram of the relationship between the graph of the characteristic quantities in Figure 3 and the set values,
Figure 4 is a relationship diagram between the characteristic quantity graph in Figure 3C and the setting value, Figure 4C is a relationship diagram between the characteristic quantity graph in Figure 3e and the setting value, and Figure 4d is a relationship diagram between the characteristic quantity graph in Figure 3e and the setting value. FIG. 3 f is a relationship diagram of the characteristic quantity graph and setting values, and FIGS. 5 a and 5 b are a side view and a plan view of the component inspection device. 1... Circuit board, 2... Parts, 3.4
...Lighting device, 5.6...Shadow, 7...
...TV camera, 8...Image recognition device, 9
, 10...Histogram area. Name of agent: Patent attorney Shigetaka Awano and 1 other person 1st
Fig. 2 ■ Fig. Fig. 2

Claims (1)

[Claims] The brightness histogram of the range where shadows are created by a lighting device installed diagonally above the parts to be inspected for each component of multiple inspection boards as a standard inspection target for setting the set values that serve as inspection standards, and the area where shadows do not occur. A first step of calculating the luminance histogram of the range, a second step of statistically processing each brightness histogram for each component of each board obtained in the first step to obtain a characteristic amount, and a second step of obtaining a characteristic amount of each component of each board obtained in the second step. The third step is to use the value obtained by statistically processing the characteristic quantities for each component as a set value for determining the presence or absence of a shadow on the component, and the brightness histogram of the shadow-forming range of each component on the inspection board and the shadow-free range. A fourth step of obtaining a brightness histogram of
The fifth step is to statistically process each brightness histogram for each part obtained in the process to obtain the characteristic quantity, and the characteristic quantity of the actual inspected part determined in the fifth process and the set value of each component determined in the third process are A component inspection method comprising a sixth step of comparing each component to determine the presence or absence of a shadow, and a seventh step of determining the presence or absence of a component based on the presence or absence of a shadow.