JPS61188056A - Positioning system between printed circuit board and machining device - Google Patents

Abstract

PURPOSE:To make speedy positioning performable, by putting the specified-form flag, varying in both X and Y direction, on a printed circuit board, while finding the slippage with an image pickup device and compensating it. CONSTITUTION:A triangular flag B put on a printed circuit board is written to a picture memory consisting of a one bit picture element memory eisposed in matrix form at a visual field of a camera. And, a central processing unit finds a Y direction slippage value DELTAY from a distance Dpq between both edges p and q of the flag B on a horizontal line HL, another distance DPQ between P and Q at the time of being correctely positioned and weight H, among picture element data. And likewise, it finds an X direction slippage value DELTAX from a distance Drs between (r) and (s) on a vertical like VL, another distance DRS between R and S at a right position and base length W. On the basis of this slippage value, a relative position between the PCB and the camera is compensat ed, thus positioning takes place. Doing like this, speedy position is made perform able.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a positioning system for positioning a printed circuit board used for assembling various electronic ports and paths with processing equipment.

Conventional technology □ When performing various processing on a printed circuit board, such as printing wiring layers, soldering layers, mounting elements, etc., the printed circuit board is first mounted on a processing table, and then accurately connected to processing equipment. It is necessary to perform accurate positioning.

In the conventional positioning method, a printed circuit board with positioning marks attached to predetermined locations is mounted on a processing table, and an imaging device and servo system mounted on the processing equipment are used to locate the markings on the printed circuit board into the imaging device. The relative position of the processing table and processing device is controlled in the X and Y directions until the processing table and the processing device are captured at the center of the field of view.・ □ In other words, as illustrated in Fig. 4, the field of view A of the imaging device
Capture the mark B on the printed circuit board within the image, and count the number of pixels in the hatched overlapping part so that it overlaps with the broken line part C set at the center of the field of view. Follow-up control in both the X and Y directions was performed in the direction in which this value increased.

Problems to be Solved by the Invention The conventional value control method described above has a problem in that positioning takes time because it includes a feedback loop.

Means for Solving the Problems in the Structure of the Invention The positioning method of the present invention, which solves the problems in the prior art described above, attaches a mark with a predetermined shape that changes in both the X and Y directions on the printed circuit board, and The amount of deviation in the Y direction and the X direction is calculated from the width in the Y
By correcting in the positioning direction, it is configured to perform quick positioning without relying on follow-up control.

Hereinafter, the effects of the present invention will be explained in detail with reference to Examples.

Embodiment FIG. 1 is a block diagram showing the configuration of a printed circuit board processing apparatus to which an embodiment of the present invention is applied.

Reference numeral 1 denotes a processing table, on which a printed circuit board 2 to be processed is mounted by an appropriate automatic mounting device (not shown). The mark attached to the printed circuit board 2 is imaged by a camera 3 mounted on various processing devices (not shown). The image signal output from the camera 3 is transmitted to the quantization circuit 4
After being quantized in , it is written to an area at a predetermined address in the screen memory 5. The write address at this time is supplied from the address counter 7 to the screen memory 5 via the selector 8.

The central control unit (CPU) 6 detects the positional deviation of the printed circuit board 2 by processing the quantized image signal read from the screen memory 6, and performs positioning based on the amount of deviation.

The printed circuit board 2 is placed on the processing table 1 while being roughly positioned with such precision that the mark mA is captured within the field of view of the camera 3 using appropriate positioning aids such as positioning pins planted on the processing table 1. It is placed.

FIG. 2 illustrates the relationship between the field of view A of the camera 3 and the mark B captured within this field of view. This mark vaB is
It has a triangular shape that changes shape in both Y directions.

The sign B in the field of view A is displayed brightly (“
1°) and dark (“O”) binary data.

On the other hand, a triangle/shape C indicated by a dotted line in FIG. 2 indicates the position of the marker within the field of view when the printed circuit board 2 is correctly positioned with respect to the processing device equipped with the camera 3.

Of the pixel data written in the screen memory 5, the CPU 6 selects a horizontal line H passing through the center of the screen as shown in FIG.
Continuously read out only those existing on the horizontal line HL, and calculate the distance D□ between both edges (boundary between the sign and the background) p and q of the mark iB existing on the horizontal line HL, that is, the direction of the mark B along the horizontal line H. Find the width of. As shown in FIG. 2, this edge-to-edge distance has a value equal to the distance DP between points P and Q when the printed circuit board is correctly positioned. Therefore,
When the base of mark B is parallel to horizontal bar HL, Y of mark 1lIiB on this printed circuit board 2 (in this case, processing table 1)
The amount of deviation ΔY in the direction is as follows.

ΔY-(1/2)H(ni(D,,/D?.)] However,
H is the height of the triangle forming mark B.

Next, the CPU 6 continuously reads out only the pixel data written in the screen memory 5 that exists on the vertical line VL passing through the center of the screen as shown in FIG. The distance D□ between both edges r and S of the label B present above is detected. As shown in FIG. 2, this edge-to-edge distance has a value equal to the distance I)+ts between points R and S when the printed circuit board is correctly positioned. Therefore,
The amount of deviation ΔX of the mark B (processing table 1) in the X direction is as follows.

ΔX= (1/2)W (1-(Drs/Dos)
) However, W is the length of the base of the triangle forming the mark mB.

The CPU 6 is misaligned as described above! When ΔX and ΔY are calculated, X is converted through the A/D conversion circuit.

While checking the position signals from the Y position sensors sx and sy,
X and Y feed motor M via motor drive circuit 9
By rotating X and MY, the processing table 1 is moved to X by the detected positional deviation amount ΔX and ΔY.

Feed in the Y direction and position.

FIG. 3 is a circuit diagram showing an example of the configuration of an edge detection circuit installed at appropriate locations inside and outside the CPU 6.

The pixel columns on the horizontal line HI7 successively read out from the screen memory 6 are supplied to the shift register 11. Each bit being shifted within this shift register 11 is supplied to AND gates 12 and 13. Assuming that the image data is quantized such that the marker part is 1" and the background part is 10", the AND gate 12 will quantize the leading 3 bits to be all 11" and the trailing 3 bits to be 1". The starting edge of the marker is detected since all the values are 0''.

On the other hand, the AND gate 13 has all three leading bits “O”.
”, the trailing 3 bits are all 11°, so the terminal edge of the label is detected.

A counting circuit (not shown) that counts clock signals having a speed equal to the shift speed of the shift register 11 is activated by the label start edge detection signal outputted from the AND gate 12. The count value of this counting circuit is AND gate 1
3 is held in the launch circuit by the label end edge detection signal outputted from 3. The retained count indicates the edge spacing (width of the marker) in pixels.

Above, we have exemplified the configuration in which the marker is captured within the field of view of the camera 3 using the positioning pin installed on the processing table 2. However, due to the balance between the positioning accuracy of such a positioning pin and the width and narrowness of the camera's field of view, it is difficult to capture the marker within the field of view. If the position cannot be captured, an appropriate coarse adjustment stage including return and coarse feed may be provided before the final positioning stage according to the method of the present invention.

In addition, while the relative position between the camera 3 and the processing table 1 is fixed, the label read in the screen memory 5 is scanned horizontally and vertically to calculate the edge interval. The configuration may be such that the edge spacing in the X and Y directions of the sign is calculated by moving one of the platforms 1 in the horizontal and vertical directions only once. In this configuration,
Camera 3 does not necessarily have to be a two-dimensional sensor.
A dimensional sensor or a sensor for one pixel may be used.

In addition, although we have shown an example of a configuration in which the processing device on which the camera 3 is mounted is fixed and the processing table 1 on which the printed circuit board 2 is mounted is moved, conversely, the processing device side on which the camera 3 is mounted is fixed and the camera 3 is mounted. It is also possible to have a configuration in which the processing equipment side that is being moved is moved.

Moreover, although a triangular sign is illustrated, any other suitable shape such as a circle or an ellipse may be used as long as the sign changes in shape in the X and Y directions.

Effects of the Invention As explained in detail above, the positioning method of the present invention has the following effects:
A mark with a predetermined shape that changes in both the X and Y directions is attached on the printed circuit board, and the width in the Y direction and the Since the positioning is performed by calculating the amount of deviation and correcting the relative position of the printed circuit board and the imaging device in the X and Y directions by the calculated amount of deviation, it is faster than the conventional method using follow-up control. Positioning can be performed.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of a processing device to which a positioning method according to an embodiment of the present invention is applied; FIG. 2 is a conceptual diagram illustrating the relationship between the field of view of an imaging device and a mark captured by it; FIG. 3 is a circuit diagram showing an example of the configuration of an edge detection circuit;
FIG. 4 is a conceptual diagram illustrating the relationship between the field of view of a camera and the mark captured by the camera in a conventional positioning method. l...processing table, 2...printed circuit board, 3...imaging device,
4...Quantization circuit, 5...Screen memory, 6...CPU,
10...Motor drive circuit, MX...X feed motor, MY...Y feed motor, A...field of view of imaging device,
B... Mark captured within the field of view of the imaging device, C... Mark position in the field of view after positioning, HL... Horizontal line passing through the center of the field of view, VL... Vertical line 6 passing through the center of the field of view Patent applicant Japan Denki Home Electronics Co., Ltd.

Claims (1)

[Claims] A positioning mark is formed at a predetermined location on the printed circuit board, and the relative position of the printed circuit board and the imaging device is adjusted by In a printed circuit board positioning method in which the printed circuit board and the processing device are positioned by adjustment in the Y direction, the mark has a predetermined shape that changes in both the X and Y directions, and the mark within the field of view of the imaging device is The amount of deviation in the Y direction and the X direction is calculated from the width in the A printed circuit board positioning method characterized by positioning by correcting.