JPH0810800B2 - Part lead inspection and attitude recognition method - Google Patents

Description

The present invention relates to a method for inspecting bending of a lead portion of a component and recognizing the posture of the component, and a line sensor / camera for determining the posture of the component and detecting the lead bending amount. -The camera captures each lead side of the component, binarizes multi-valued image information and stores it in memory, and determines the lead position and lead pitch based on the binary image information on the memory, and the left and right pitches are equal The center position of the lead side is calculated from the lead position, and for parts with lead sides on four sides, the center position of the entire part and the amount of positional deviation are calculated from the central position of each lead side, and the position of the part is calculated according to the amount of positional deviation. After performing the correction, the lead side of the position-corrected part is imaged by the line sensor camera, the binary image information is stored in the memory, and whether the correction is complete based on the binary image information is performed. Confirm. For a component having lead sides only on two sides, the center position of the entire component and the amount of displacement are calculated from the center position of the lead side and the lead tip (or root) position.

[Industrial applications]

The present invention relates to a method of inspecting a bending of a lead portion of a flat lead package type component and a method of recognizing a posture of a component, which has been increasing in recent years.

[Conventional technology]

Conventionally, the lead bend inspection of flat lead package type parts is performed by imaging the lead part of the part with an area camera or line sensor camera, A / D converting the video signal, and bending amount of the lead part with a digital signal. The method of measuring is adopted.

[Problems to be Solved by the Invention]

However, in order to obtain sufficient measurement accuracy with the miniaturization of target parts or the miniaturization of lead parts and printed circuit board patterns, (a) the area camera has a small number of constituent pixels per side of the CCD element. , It is necessary to increase the magnification of the imaging optical system and capture many screens.

(B) Since the line sensor / camera can obtain only one line of image information for each image pickup, an error is likely to occur in the measurement due to the positional deviation between the target component and the line sensor / camera.
It is necessary to recognize the posture of the component and perform highly accurate position correction.

There was such a problem.

In the method (b), if the line sensor and the inspection target component are misaligned, the pitch information between the leads becomes different. In addition, after the lead bending inspection, when arranging parts on a predetermined pattern of the printed board, the package of the parts has a considerable distortion at the time of manufacturing, so the center position of the package and the pattern on the printed board should be aligned. Even if it does, it cannot always be implemented correctly. Therefore, in order to perform accurate alignment, it is necessary to find the center position of the entire component (package and lead) from the component lead position and correct the positional deviation from the package center position.

The present invention was created in view of this point,
The purpose is to detect the lead bending amount at the same time that the line sensor / camera determines the posture of the component.

[Means for solving problems]

FIG. 1 (a) is a principle diagram of the first invention of the present invention, and FIG. 1 (b) is a principle diagram of the second invention. The present invention detects the amount of lead bending, simultaneously calculates the center position of the entire component from the lead position, and calculates the amount of positional deviation from the center of the package. A first aspect of the present invention relates to a component having lead sides on four sides, in which each lead side of the component is imaged by a line sensor camera, and multi-valued image information output from the line sensor camera is displayed. Binarize, store the binary image information in the memory, calculate the lead position and the lead pitch based on the binary image information in the memory, and calculate the center position of the lead side from the lead position where the left and right pitches are equal. For parts with lead sides on the four sides, calculate the center position of the entire part and the amount of misalignment based on the lead from the center position of each lead side, and correct the position of the part according to the calculated misalignment amount. , The lead side of the component whose position has been corrected is again imaged by the line sensor camera, the binary image information is stored in the memory, and whether the correction is complete based on the binary image information in the memory is checked. Be sure.

This is a constituent requirement.

The second invention relates to a component having lead sides only on two opposite sides, and the tip (or root) of the lead.
The position is obtained, and the center position of the entire component and the amount of positional deviation based on the lead are calculated from the center position of each lead side and the tip (or root) position of the lead. The other points are the same as those of the first invention.

〔Example〕

FIG. 2 is a block diagram showing a system configuration example of the present invention. The illumination unit 1 is arranged above the inspection target component 3, and a white light diffuser plate 2 is provided between the light emitting surface of the illumination unit 1 and the component 3 in order to obtain a clear image of light and dark. The imaging unit has a camera / lens 5, a CCD line sensor / camera 6, and the like, and images from below the inspection target component 3 to capture a silhouette image of the lead portion. The image processing unit uses a microprocessor 10 that processes data and an analog signal from the CCD line sensor / camera 6 to the microprocessor 10.
A camera interface 7 for A / D converting based on a control signal from the device and storing it in the memory 8, a memory 8 for storing digitized image information, a mechanical interface 9,
It is composed of a CRT controller 11 for outputting the inspection result to a CRT, an external storage device 13 for storing the inspection result, and an external storage device controller 12. Mechanical interface 9
Is for controlling a robot (not shown) that holds and moves the inspection target component and a robot that moves the camera.

FIG. 3 is a diagram showing an inspection flowchart. A specific inspection method will be described below. First, set the parts to be inspected at the inspection position (mounting position on the printed board),
Move the line sensor camera to the position of each lead side. When the movement is completed, the silhouette image of the lead part is captured, and the camera interface digitally converts the analog waveform obtained from the line sensor camera with the A / D converter and obtains its peak value. Next, the line sensor camera captures an image again using about 1/2 or 1/3 of the calculated peak value as a threshold value, and the brightness level is "0" or "1" while comparing the camera output wave with the above threshold value by the comparator. The binary image of is taken into the memory.

In the binary image information on this memory, the bit position of the brightness level "0" indicating the lead portion is counted to obtain the number of positions n, and the lead portion of the normal component that has been obtained in advance is imaged with the optimum threshold value. The number of positions N of the brightness level “0” indicating the lead portion in the binary image obtained by the above is compared, and if the number of positions n is far from the value N, the threshold value is changed and the binary image is captured again. , Repeat the same operation.

If the number of positions n is sufficiently close to the value N that has been obtained in advance, the reversal position of the brightness level indicating the edge part of the lead from "1" to "0" and "0" to "1" from the captured binary image To find the lead position and the number of leads.

If the number of leads is not equal to the specified value, it is rejected as a lead break or a large positional deviation. If it is equal to the specified value, the lead position is set to the center position of the lead portion and the lead pitch is calculated and stored in the memory. If the part to be inspected is rotating, the pitch is longer than the regular one. Here, the center position of the lead side is calculated from a plurality of lead positions having the same pitch between the left and right leads. Fourth
The figure shows an example of a multi-valued image and a binary image of the lead portion. The lead position and the lead pitch are calculated based on the binary image.

Furthermore, for parts to be inspected with only two leads, move the camera back and forth, capture a binary image, and count the number of pixels with a brightness level of "0" that indicates the lead part, and ) Discover the part.

The above operation is performed for each side, and for a part with four lead sides, the center position and rotation amount of the entire part with respect to the lead is calculated from the center of the four sides. For a part with two lead sides, From the center of the two sides and the position of the tip of the lead, the center position and the rotation amount of the entire component with respect to the lead are calculated. FIG. 5 shows the center of the lead side and the tip of the lead in a component having leads on only two sides.

Next, it is determined whether or not the lead pitch of each side obtained earlier than the obtained rotation amount is within the specified range. If it is out of the specified range, the lead is bent, so it is rejected. If it is within the specified range, the position is corrected. Finally, the binary image is captured again for one side or each side, and it is determined from the lead positions at both ends and whether or not the correction is better.
As shown in FIG. 6, a component (for example, LSI20) determined to be OK in the inspection of FIG.
The lead portion of the and the connection pattern on the printed board 30 are soldered.

FIG. 7 is a diagram for explaining a method of setting the binarized slice level. When an image of the lead part of the rugged part of FIG. 6A is taken by a line sensor, the light is blocked at the lead part because it is transmitted illumination, and in the case of a multi-valued image, the lead part is shown as shown in FIG. Become a valley. Now, when the slice level is set to a high luminance position as indicated by A in FIG. 2B, the obtained binary image has a wide luminance level “0” portion indicating the lead portion as shown in FIG. Become. On the contrary, if the slice level is set at a low luminance position such as B in FIG. 6B, the obtained binary image has a narrow luminance level “0” portion indicating the lead portion as shown in FIG. Become. In this way, depending on the slice level to be set, the width of the lead portion on the binary image becomes wider or narrower than the actual width of the lead portion. In the present invention, the center position of the "0" portion of the brightness level of the binary image is searched to find the position of the rud part. However, the width of the lead part on the binary image is extremely wide or narrow. If so, the center position tends to vary. Therefore, the slice level is set so that the actual lead width and the lead width of the binary image always match.

FIG. 8 is a diagram for explaining a method of calculating the center position of the lead side. A brightness level “0” part is searched from the obtained binary image, and a center position is obtained for each of the brightness level “0” parts, and each read position I _k is set. Further, by taking the difference between each obtained lead position I _k and the next lead position I _{k + 1} , the lead pitch P _k can be obtained. Lead N + now
Considering 1, the distance to the lead on the left side is P _n , the distance to the lead on the right side is P _{n + 1} , and if N + 1
If is curved, ΔP _n = | P _n −P _{n + 1} | becomes large. Therefore, for each lead, this ΔP _k
Is calculated, compared with the specified value, and the bend is inspected. According to this method, even if the θ deviation of the portion is to some extent (± 10 °), if the lead is not bent, ΔP _k ≈0, and the rotational deviation is not so much affected. Next, the position I _{k of} the lead (for example, N + 3 in the figure) that can be determined as not bent by the above-described bending inspection and the position J _k where the lead is located when the part is imaged by the line sensor without displacement. Find the difference Δd _k = J _k −I _k . Δd _k is obtained for each of the non-bent leads, summed, and divided by the number of non-bent leads to obtain the average displacement amount ΔD. The center of the lead side of the component can be obtained by summing this ΔD and the center position C of the lead side when the component is imaged by the line sensor without displacement.

FIG. 9 is a diagram illustrating a method of calculating the center position of the entire component from the lead. First, a portion having lead sides on four sides will be described. The center position of each lead side of the component is obtained by the above method. S ₀ , S ₁ , S ₂ , S in FIG.
Reference numeral ₃ indicates the center position of each lead side in the portion where the lead side is on the four sides. Further, the coordinates of the center C of the component when the component is not displaced are also known. Center position of each side S ₀
By obtaining a to the intersection of the two connecting the centers of the opposing two sides with S _3, the central position of the component C 'is obtained. Further, the inclination θ of the component is an angle formed between the X axis or the Y axis of each line segment.

Next, a part having two lead sides will be described.
The center position of each lead side of the component is obtained by the above method. In FIG. 3B, S ₀ and S ₁ indicate the center position of each lead side in a component having two lead sides. Also,
The coordinates of the lead tip position and the center C of the component when the component is not displaced are also known. The intersection of the line segment connecting S ₀ and S ₁ and the line segment passing through the center position of each lead tip position and parallel to the X axis is the center position C ′ of the component. Also, the inclination of the component θ
Is the angle formed by the line segment connecting S ₀ and S ₁ with Y.

Next, the calculation of the positional deviation amount will be described. The coordinates of the point C ′ are (x ₁ , y ₁ ) and the coordinates of the point C are (x ₀ , y ₀ ).
And

Now, considering a coordinate system having the point C as the origin, the coordinates of the point C ′ can be converted into C ₁ (x _1- x ₀ , y _1- y ₀ ). Since the component has an inclination of θ, C ₁ rotates to C ₂ (x ₂ , y ₂ ) when the position correction in the θ direction is performed by rotating −θ about this origin. The coordinates of this C ₂ (x ₂ , y ₂ ) are x ₂ (x ₁ −x ₀ ) cos (−θ) − (y ₁ −y ₀ ) sin (−θ) y ₂ = (x ₁ −x ₀ ) becomes _{sin (-θ) + (y 1} -y 0) cos (-θ).

〔The invention's effect〕

As is clear from the above description, according to the present invention, (a) the processing speed is high because the line sensor camera is used.

(B) Since the posture determination is performed at the same time as the lead bending inspection, the measurement error due to the positional deviation is small.

(C) Since the number of pixels per line is larger than that of the area camera, the resolution is high and the accuracy is good.

You can play a remarkable progress.

[Brief description of drawings]

FIG. 1 is a principle diagram of the present invention, FIG. 2 is a diagram showing a system configuration example of the present invention, FIG. 3 is a diagram showing an inspection flowchart,
FIG. 4 is a diagram showing a multivalued image and a binary image of the lead portion, and FIG.
Figure shows the center position of the lead side and the tip of the lead. Figure 6 shows the LSI and printed board. Figure 7 shows the method of setting the binarized slice level. Figure 8 shows the lead side. FIG. 9 is a diagram illustrating a method of calculating the center position of the component, and FIG. 9 is a diagram illustrating a method of calculating the center position of the entire component from the lead. 1 ... Illumination part, 2 ... Light diffusing plate, 3 ... Parts to be inspected,
4 ... Lead, 5 ... Camera lens, 6 ... CCD line sensor camera, 7 ... Camera interface, 8
... Memory, 9 ... Mechanical interface, 10 ... Microprocessor, 11 ... CRT controller, 12 ... External storage device controller, 13 ... External storage device.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display H05K 13/04 M

Claims (2)

[Claims] 1. A method for inspecting a component lead and recognizing the posture of a component by using a line sensor camera to inspect bending of a lead portion of the component and recognizing the posture of the component. The sides are imaged, the multi-valued image information output from the line sensor / camera is binarized, the binary image information is stored in the memory, and the lead position and the lead pitch are determined based on the binary image information on the memory. Then, the center position of the lead side is calculated from the lead positions where the left and right pitches are equal. For parts with lead sides on four sides, the center position and position of the entire part based on the lead from the center position of each lead side The amount of displacement is calculated, the position of the component is corrected according to the calculated amount of displacement, the lead side of the component for which the position has been corrected is imaged with a line sensor camera, and binary image information is recorded. Stores in,
A method for inspecting a component lead and recognizing a posture, which comprises confirming whether or not a correction is complete based on the binary image information on a memory. 2. A method for inspecting a component lead and recognizing a posture of a component by using a line sensor camera to inspect bending of a lead portion of the component and recognizing the posture of the component, wherein each lead of the component is detected by the line sensor camera. The sides are imaged, the multi-valued image information output from the line sensor / camera is binarized, the binary image information is stored in the memory, and the lead position and the lead pitch are determined based on the binary image information on the memory. Calculate the center position of the lead side from the lead position where the left and right pitches are equal, and for parts that have lead sides only on two opposing sides, find the lead tip (or root) position and calculate the center of each lead side. From the position and the tip (or root) position of the lead, calculate the center position of the entire component and the amount of positional deviation with the lead as the reference, and correct the position of the component according to the calculated amount of positional deviation. Re-imaging the lead side of the corrected component with the line sensor camera, storing the binary image information in the memory, and recognizing whether the correction is complete based on the binary image information in the memory. A method for inspecting a component lead and recognizing a posture of the component lead.