JPH0273700A - Electronic component automatic mounting method - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for automatically mounting electronic components onto a printed circuit board, and particularly relates to a method for automatically mounting components for imposition of flat package ICs and the like.

[Conventional technology]

As a conventional automatic mounting method for electronic components, Japanese Patent Application Laid-Open No. 62-8
A technique described in Japanese Patent No. 6789 is known. In this conventional technology, the part gripped by a chuck is imaged by a TV, a camera, etc., and this image information is processed. ) Determine the center position of the row, and from the center position of the contact rows on each side, determine the center position and rotational direction of this imposition component, and based on this information, imposition the component on the contact pattern of the printed circuit board. The parts are moved by a robot during the imposition process so that the contacts are aligned, and each contact is connected.

[Problem to be solved by the invention]

In the above-mentioned conventional technology, when determining the center position of a contact row from an image of an electronic component, a virtual measurement line that crosses the contact row is set, a point of change in brightness on this virtual measurement line is determined, and two points are calculated. The middle point of the bright area sandwiched between the change points is taken as the contact point position, and the average value of each contact point position is taken as the center position of the contact point row. Even if the virtual point measurement line is set in rough register, the virtual measurement line crosses all the contacts in the contact array. this is,
This is because when an electronic component is gripped by a mechanical chuck, the posture of the electronic component becomes approximately constant, and rough positioning is possible. That is, in the prior art, it is assumed that the posture of the electronic component held by the chuck is substantially constant, and the accurate posture of the electronic component is obtained by image processing.

Mechanically gripping an electronic component has the risk of bending the leads (contact points) of the electronic component during the gripping stage. For this reason, relying on mechanical means is not very desirable. Therefore, a method of adhering the electronic components to the hands of the robot using vacuum suction or the like may be considered, but if this method is used, the posture of the electronic components taken out by the hands of the robot from the pallet of electronic components will not be constant. Since a virtual measurement line cannot be set, the above conventional technique cannot be applied.

An object of the present invention is to provide an automatic electronic component mounting method that determines the center position of a contact row without setting a virtual measurement line and eliminates the need to use mechanical means to take out electronic components from a pallet. It is in.

[Means to solve the problem]

The above problem is solved by an automatic electronic component mounting device that is equipped with a printed circuit board transport device, a pallet containing electronic components, and a robot that takes out the electronic components from the pallet and mounts them on the printed circuit board. When mounting an electronic component with multiple contacts on a printed circuit board, the electronic component is imaged with a blinding board as a background, and the resulting image of the electronic component is processed to determine the position and rotation direction of the electronic component. Find a straight line connecting the centers of gravity of the images of each contact point that makes up the contact row, find the brightness change point of the image on the straight line, set the midpoint of the bright area between the two change points as the contact point, and set each contact point. This is achieved by determining the position and rotation direction of the electronic component using the average value of the positions as the center position of the contact row.

[Effect]

According to the automatic loading method of the present invention, instead of setting a virtual measurement line, a straight line that intersects the contact row from the center of gravity of the image of each contact that makes up the contact row is obtained. Even if the posture of the electronic component is not roughly determined, the accurate position and rotation direction of the electronic component can be determined. This makes it possible to use, for example, a robot that employs a vacuum suction method without using any mechanical means, eliminates bending of contacts during automatic mounting, and simplifies the automatic mounting device.

〔Example〕

Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

FIG. 5 is an external view of an automatic loading device to which an automatic loading method according to an embodiment of the present invention is applied. In this automatic mounting device, first, the board transfer machine 1 fixes the printed circuit board 2 at a fixed position. This printed circuit board 2 has a contact pattern 2α
is printed. The robot 3 is equipped with a vacuum suction chuck 6 that moves in the X and Y directions, and uses the chuck 6 to take out one of the electronic components 5 on the pallet 4. And robot 3
The removed electronic component 5 is moved to a position directly above the TV camera 7 and held still. FIG. 6 is a diagram explaining the state at this time. The TV camera 7 is fixed upward so that the central axis of the chuck B and the optical axis are in the same direction. A dark-colored blindfold plate 9 is attached to the chuck 6 so that the TV camera 7 captures only an image of the electronic component 5.

When the TV camera 7 takes an image of the electronic component 5, the chuck 6 stands still at a position where its center axis coincides with the optical axis of the TV camera 70 and the distance between the electronic component 5 and the TV camera 7 is always constant. takes an image of the electronic component 5 from directly below.

The image of the electronic component 5 obtained by the TV camera 7 is sent to the image processing device 8 shown in FIG. The positional deviation and rotational deviation are determined as described later, and the deviation information is sent to the robot 3. The robot 3 corrects the posture of the electronic component 5 that is attracted to the chuck B according to the displacement information from the image processing device 8, so that each contact protruding from the side of the electronic component 5 matches the contact pattern of the board 2. Install it to match 2a. When the electronic components 5 have been mounted on the printed circuit board 2, the board transfer machine 1 discharges the mounted printed circuit board, fixes a new printed circuit board 2 in the same position,
The electronic component 5 is mounted on this new printed circuit board 2 by repeating the same operation.

FIG. 7 is a diagram explaining the principle of a method for determining the position and rotation direction of an electronic component. In FIG. 7, six rectangles 20 in the - column are shown.
arranged in a square. Each rectangle 20 represents an electronic component 5
This is an image of six contacts protruding from each of the four sides.

From the arrangement of the images of the contact points, the positional coordinates (X, Y) of the center O of the electronic component 5 and the vector D indicating the rotational direction of the electronic component 5 are determined by the following procedure.

First, the center position of one row of six contact points on each side is set as the center point α1
blcld, the center positions a, b,
Coordinates of c, d (μm1 $11), (”t + 1
'! )1(μ1.ν, ), (,.,ν4) are found.

Then, find the straight line - connecting the center positions α, C and the straight line f connecting the center positions S, ti, and set the intersection of the straight line -0f to the center position o (x, y) of the electronic component 5, and set the straight line - 1
The rotation direction of the electronic component 5 is calculated from the bisector of f.

Next, how to determine the center positions α to d of the contact row will be explained with reference to FIGS. 1 to 4.

FIG. 2 is a binarized image of the X child component. The electronic component shown in the image of Figure 2 consists of a dark-colored, approximately square package part, and six contacts (leads) protruding in rows on each of the four sides.
It consists of In the binarized image of only the electronic components whose background is blocked by the blinding plate 9 shown in FIG. 6, the contact points are bright and the other parts are dark. From this series of contact images 20, the center position of each row of contact points is determined. So, first of all.

As shown in FIG. 3, the center of gravity position (x mark) of each contact point image is determined. Any method may be used to determine the center of gravity, and the present invention is not limited to any method. Note that the method for determining the center of gravity is not the main idea of the present invention, so the explanation thereof will be omitted.

Next, a straight line (broken line 21 in FIG. 3, hereinafter referred to as the lead row center line) connecting the centers of gravity of the contact images of each contact row is determined as follows.

First, the linear equation is expressed as αx+by+c=O M = 1. At this time, the distance from a certain point (χ+, y+) is 1
A threshold value is set for the α phrase +71y+"cl. Here, the threshold value is used to determine whether or not the center of gravity exists on a given straight line. Therefore, the two centers of gravity on the same straight line Make the value smaller than the minimum distance value.

FIG. 1 is a flowchart showing the procedure for calculating the lead row center line. First, any two centers of gravity (X, ,
Step 51) Extract Y, ), (xt, Y,), and draw a straight line alx"bl y" passing through these two points.
Find c = 0 (step S2). Next, l azI
Find all the centroids (Xi, Yi) of In step S4), if the number of centers of gravity is 1, then the straight line a++bly
+. =0 is registered 1# (step 55). Then, the center of gravity found in step S3 and the first two centers of gravity are removed from the group of centers of gravity (step S6), and if any center of gravity remains (step S7), the process returns to step 51 and the same process is repeated. In step S4, if the predetermined number is not reached, it is thought that the cause is that a straight line spanning multiple contact rows as shown by the dashed line in FIG. Select and repeat the same process.

Once the lead row center line is determined as described above, next
As shown in the figure, the point of change in brightness (X mark) on the center line of this lead row is determined. This point corresponds to the boundary of contact surface 1#20 in the binary image. Then, the bright area, that is, the midpoint of the two change points that sandwich the contact image 2o (○
mark) and use this as the position of the contact. Once the respective positions of the contacts constituting the contact array have been determined (t-), the average position (marked ◎) of all the positions, six contact positions in this embodiment, is determined.

This is assumed to be the center position C of the contact row explained in FIG. 7, and the center positions α, b, and d of each contact row are obtained in the same manner, and the vector D indicating the position O and rotation direction of the electronic component is obtained.

In this way, since the center line required to calculate the center position of the contact row is determined from the image of the electronic component, it does not matter what the orientation of the electronic component is when it is attracted to the chuck. The degree of freedom in selecting the electronic component gripping means is improved, and the configuration of the device can be simplified.

[Effects of the Invention] According to the present invention, the configuration of an automatic electronic component mounting apparatus is simplified, and bending of leads due to accidents during electronic component mounting is eliminated.

[Brief explanation of the drawing]

FIG. 1 is a flowchart showing a procedure for calculating a lead row center line in an electronic component mounting method according to an embodiment of the present invention;
Fig. 2 is a diagram showing a binary image of an electronic component, Fig. 3 is an explanatory diagram of the lead row center line, Fig. 4 is an explanatory diagram of how to find the contact row center position, and Fig. 5 is an illustration of the automatic mounting device. An external view, FIG. 6 is a diagram showing the positional relationship between the electronic component attracted to the chuck and the TV left camera, and FIG. 7 is an explanatory diagram for determining the component position and rotation direction of the electronic component. 1・・・・・・・・・・・・・・・・・・・・・・・・
Board transfer machine 2・・・・・・・・・・・・・・・・・・
・・・・・・Printed circuit board 6・・・・・・・・・・・・・・・
・・・・・・・・・・・・ Robot 4・・・・・・・・・
・・・・・・・・・Encircle・・・・Palette 5・・・・・・・
・・・・・・・・・・・・・・・・・・Electronic parts 6...
・・・・・・・・・・・・・・・・・・Adsorption type chuck 7・・・・・・・・・・・・・・・・・・・・・
・・・Camera 8・・・・・・・・・・・・・・・・・・
・・・・・・Image processing device 9・・・・・・・・・・・・
......Blind plate 20...
・・・・・・・・・・・・Contact image 21 ・・・・
・・・・・・・・・・・・・・・Lead row center line α
, b, c, cl...Contact row center position 0...
・・・・・・・・・・・・・・・Electronic component position D ・・・
・・・・・・・・・・・・・・・・・・ Vector agent indicating the direction of rotation Patent attorney Masaru Ogawa Oga 1 Figure 2 Shiba 5 Figure Crab 5 Figure 44 Figure iG diagram

Claims (1)

[Claims] 1. An automatic electronic component mounting device comprising a printed circuit board transfer device, a pallet containing electronic components, and a robot that takes out electronic components from the pallet and mounts them on the printed circuit board, which has multiple contact points arranged in a straight line. When mounting an electronic component on a printed circuit board, the electronic component is imaged with a blinding board as a background, and the resulting image of the electronic component is processed to determine the position and rotation direction of the electronic component, forming a contact array. Find a straight line connecting the center of gravity of the image at each contact point, find the brightness change point of the image on the straight line, and
The middle point of the bright area sandwiched between two change points is taken as the contact point position, and the average value of each contact point position is taken as the center position of the contact point row,
An automatic electronic component mounting method characterized by determining the position and rotation direction of the electronic component.