JPH0810799B2 - Electronic component alignment method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for automatically mounting electronic parts on a printed circuit board, and more particularly to a method for aligning electronic parts by visualizing the automatic mounting.

[0002]

2. Description of the Related Art Up to now, the mounting of electronic components on a printed circuit board is known, for example, as disclosed in Japanese Patent Laid-Open No. 60-1900.

[0003]

However, in this case, since the positioning mark is required for recognizing the pattern position on the substrate, it is necessary to change the design of the substrate. Also, IC pins (terminals or leads)
(Also referred to as)) , the accuracy cannot be expected because it recognizes only a specific pin position. Further, since the position recognition of the IC depends on a plurality of visual fields, there is a problem that the recognition speed is slow.

It is an object of the present invention to provide a method of aligning electronic components, which enables the imposition electronic components to have good precision and can be quickly and automatically mounted on a printed circuit board.

[0005]

SUMMARY OF THE INVENTION The above object is to provide a method of aligning an electronic component having a plurality of terminals arranged in parallel on at least two opposite sides of the electronic component. Power is calculated from the average position of multiple terminals
Information on the position and orientation of child parts is obtained, and information on the position and orientation is obtained.
Based on the
It is achieved by adjusting to the posture .

[0006]

[Function] The measurement line (also called the sample line) set on the image
Based on the distribution of the brightness of the pixels on the measurement line, after setting the relative position of the image and the electronic component so that ( u) intersects the lead of the electronic component and satisfies the condition for capturing the electronic component in the image, Average the intersections of the above leads and the measurement line.
The average per lead row in the direction of the measurement line
Since the position is obtained, the position and orientation of the electronic component can be known,
Based on this information, the position and orientation of the electronic component is desired
It is possible to match the position and posture of.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to FIGS. 1 to 8, but before that, its theoretical background will be briefly described. When obtaining the position and orientation of an object, by averaging the positions of multiple sample points on the same object,
It is possible to detect the position and orientation with high accuracy. The accuracy increases as the number of independent sample points increases, but on the other hand, the reduction in processing speed is inevitable.

By the way, the patterns of the leads of the electronic parts and the contacts on which they are mounted are narrow in width but many in number, and are arranged in a straight line with a constant width. Also,
Due to the mechanical positioning, their rough position and orientation are known in advance. Thus, the power in the screen
It is possible to draw a sample straight line as is substantially perpendicular to the pin of the column and contacts column of the child component. Although the brightness of the images in this straight line becomes wavy in correspondence with the array of pins or contacts, one for rows of pins of the column and contacts the general there usually two or more rows, the combination of two or more columns Therefore, the overall position / orientation of them is correctly obtained.

Now, the present invention will be specifically described. First, the surface mounter according to the present invention will be described.
FIG. 2 shows the appearance of the example. As shown in the figure, the present embodiment basically comprises an orthogonal robot 1, a substrate supply device 2, an IC supply device 3 and a visual processing device 4, which are fixed on a common base. ing. In this case, the robot may be a joint type, a scalar type, or the like as long as it has sufficient positioning accuracy, and a chuck for gripping an IC as an electronic component or a TV camera for picking up an image of a board is attached to the hand. It has become. As a TV camera, another TV camera for detecting the IC position is attached to the base in a state of being fixed upward.

The outline of the surface mounter is as described above. Next, the basic operation of the surface mounter will be described with reference to the flow chart shown in FIG. 3. First, the substrate is mechanically fixed on the substrate supply device 2. By moving the TV camera fixed to the robot hand onto the board in this state, the accurate position of the pattern of the contact for mounting the IC on the board is required. After this, the hand is IC
Although the IC is moved to the supply device 3 and grips the IC from now on, the IC is moved onto the TV camera for detecting the IC position, so that the positional deviation between the IC and the hand is detected. Position of the contact patterns and IC of which is determined in the visual processing device by being fed back to the robot, the contact pattern on the substrate in which IC is about to be mounted in the aligned state is good. When the IC to be mounted still exists, the processing operation described above is repeated .

In this case, as the IC to be mounted, a surface mounting package (flat package) IC is targeted. The plane and the front surface of an example thereof are shown in FIGS. 4 (a) and 4 (b), and FIG. FIG. 5 shows a contact pattern on the board on which the IC 5 is mounted. IC as shown
5 has four rows of pins 5-1 to 5-4, from the pattern sequence 6-1 to 6-4 of the four contacts on the substrate corresponding to each of these pins columns 5-1 to 5-4 The contact pattern (6) is formed. To put correctly in a state of being associated with the pin array of the IC on the contact pattern on the substrate, it is necessary to perform alignment with high accuracy, IC chuck by mechanical positioning and a robot hand by the substrate feeder The accuracy is not sufficient, and therefore, the position is detected visually with higher accuracy and the position detection information is fed back to the robot.

As described above, the position detection is performed by the TV camera and the visual processing device, and one of the TV cameras is attached downward to the robot hand to image the contact pattern on the substrate while the other one is imaged. The base is fixed upward on the base, and the IC chucked by the hand positioned directly above the base is imaged. A method for detecting the position from the image from the TV camera is shown in FIGS. ~
The explanation will be given below with reference to FIG.

That is, on the image, the contact patterns on the substrate and the pin rows of the IC are all elongated rectangular patterns aligned in a direction perpendicular to the longitudinal direction. However, in the actual image, in addition to this, the wiring pattern and the background are also captured. Now, as shown in FIGS. 1A and 1B, a sample straight line 7 is set in a direction orthogonal to the rectangle for each column of the rectangular pattern . Below, one rectangle
The shape will be described simply as a pattern. If the position of the sample straight line 7 is fixed within the screen, the position of the pattern may be slightly shifted for each substrate or each IC, but the position can be mechanically positioned so as to always intersect with the sample straight line 7. . The brightness of the image on the sample straight line 7 in this case has a wavy shape as shown in FIG. 6 corresponding to an array of a plurality of patterns . The position is required. For example, in the example shown in FIG. 6, the boundary x _i between the pattern and the background is obtained. As shown in FIG. 7, under ideal conditions, the reflected light waveform from the pattern has a rectangular shape as shown as the brightness (I), so that the boundary of the pattern is most easily detected. ), When the waveform is distorted, the peak of the mountain (maximum point) a _i A method such as taking the center of the pattern by taking is also adopted.

The method for obtaining the boundary of the pattern will be described in detail with reference to FIG. 8. When the illumination condition is good and the screen brightness is uniform (brightness (II
In I)), the brightness threshold value is appropriately set, and the pixel positions at both ends of a brighter range or a darker range than this may be determined as the boundary of the pattern. Further, when the brightness is almost the same as the brightness (III) (brightness (IV)), the brightness becomes the same as the threshold by taking into consideration the brightness gradient between the pixels on both sides of the threshold. If the position is obtained as a real value including a decimal point, the accuracy will be further improved. Further, when the illumination condition is not good and the brightness of the screen is not uniform (brightness (V)), it is not possible to separate all patterns into a bright range and a dark range depending on one threshold value. In this case, methods such as obtaining the position of a pixel having the maximum brightness gradient between adjacent pixels as a boundary, or obtaining the weighted average A / B for each range from a mountain to a valley have been adopted. ing. However, A and B are obtained as the following formulas 1 and 2, respectively.

[0015]

[Equation 1]

[0016]

[Equation 2]

[0017] As described above, the position coordinate sequence of rectangular patterns in the sample linear direction {xi | i = 1, ·· ,
When n |} is obtained, the average value U is obtained as Equation 3 as follows.

[0018]

(Equation 3)

From the average value U, the position of each pattern row in the sample straight line direction can be obtained . If as this is the position of the sample linear direction for each column was determined, the position of the entire pattern of the IC and the contact is adapted to be determined by the following combination thereof. By the way, there are two types of flat package ICs, one having pins in four directions and the other having pins in two directions. Correspondingly, the image patterns are also shown in FIGS. 1A and 1B. There are two types. In this case, the two opposing rows are parallel to each other.

[0020] First the case of the four directions pattern shown in FIG. 1 (a), but the coordinates U1, U2, V1, V2 as each average value is obtained from the columns of four patterns, where U
1 and U2, V1 and V2 are respectively connected by a straight line, and the intersection point (U, V) is defined as the overall position, and the bisector direction of the two straight lines is defined as a vector D, which indicates the overall direction. It is supposed to be done. This vector D
Is to give rotation deviation information.

Next, in the case of the bidirectional pattern shown in FIG. 1 (b), only the accuracy in the sample straight line direction becomes a problem,
Mechanical positioning is sufficient for accuracy in the direction orthogonal to this. Therefore, the overall position (U, V) is determined as V is fixed and U is determined as (U1 + U2) / 2, and the overall direction is defined as a vector D connecting U1 and U2.

In this way, the flat package IC
And the position of contact of the pattern on the substrate are those for which it is determined correctly, the robot based on these position information and serves as a place for properly mounting the IC as imposition components on contact pattern.

[0023]

As described above , the position of the electronic component
Therefore, it is possible to mount the imposition electronic component on the printed circuit board with high accuracy and promptly and automatically.

[Brief description of drawings]

1A and 1B are views for explaining a method for obtaining a position and a rotation direction of an imposition component or a contact pattern from an image pattern.

FIG. 2 is a diagram showing an external configuration of a surface mounter according to the present invention.

FIG. 3 is a diagram showing a flow of the operation.

4A and 4B are views showing a plane and a front of a flat package IC in an example.

FIG. 5 is a diagram showing a contact pattern on which the IC is mounted.

FIG. 6 is a diagram for explaining a method of obtaining a sample point corresponding to a pattern.

FIG. 7 is a diagram for explaining a method of similarly obtaining sample points corresponding to patterns.

FIG. 8 is a diagram for explaining a method of similarly obtaining sample points corresponding to patterns.

[Explanation of symbols]

1 ... Orthogonal robot, 2 ... Substrate supply device, 3 ... IC supply device, 4 ... Visual processing device, 5 ... Flat package I
C, 5-1 to 5-4 ... Pin row, 6-1 to 6-4 ... Contact pattern row, 7 ... Sample straight line

Front page continued (72) Inventor Kyoichi Kawasaki 7-1-1 Higashi Narashino Higashi Narashino, Narashino City, Chiba Prefecture Hitachi Narashino Factory (72) Inventor Kenjiro Fujii 7-1 Higashi Narashino City, Narashino, Chiba Hitachi, Ltd. Narashino Factory (56) Reference JP 54-89760 (JP, A) JP 59-180307 (JP, A) JP 60-62200 (JP, A)

Claims (1)

[Claims] 1. A row of terminals arranged in parallel.
Capture the electronic parts equipped with multiple in the image of the visual processing device,
In addition, the condition of intersecting each of the plurality of terminals forming the row is
Set the measurement line to meet on the image, on each of the measurement line
From the brightness distribution of the pixel, the boundary of each terminal and the measurement line
The position of the intersection of the
The rows in the direction of each of the measurement lines by averaging the positions of the points
The average position of multiple terminals of
The average position of the row of terminals arranged at
From the straight lines connecting each other, the coordinates set on the image
Obtain the information of the position and orientation of the electronic component that is standardized,
Position and orientation of the electronic component based on the position and orientation information
Alignment method of the electronic component, wherein Rukoto combined in a desired position and orientation.