JP2570223B2 - Measurement device for parts position - 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 applied to mounting an electronic component such as an IC having a plurality of pins at an appropriate position on a printed circuit board, for example. For example, the present invention relates to a component position and other measuring device suitable for measuring the holding position and posture of an electronic component held by a chip mounter.

[0002]

2. Description of the Related Art When an IC such as a QFP (hereinafter simply referred to as "IC") is mounted on a printed circuit board by a chip mounter, each pin of the IC is correctly positioned on a corresponding pattern on the printed circuit board. It is necessary to mount an IC. Therefore, when the chip mounter picks up the IC, it determines whether or not the holding position and posture are appropriate, and corrects the holding posture and mounting position of the IC according to the result of the determination, and corrects the IC on the printed circuit board. Has been implemented.

Conventionally, an image processing device has been used for this type of position / posture determination. An IC held by a chip mounter is imaged by a camera at a predetermined observation position, and the input image is sent to the image processing device. After capturing and binarizing the image, the center of gravity and the rotation angle are calculated from the binary image to measure the position shift state, and the above correction processing is performed using the measurement result.

[0004]

However, in the case of the above method, if the calculation of the center of gravity and the rotation angle is performed by software processing,
It takes time to measure the position and orientation of the component, and if hardware processing is performed, the hardware configuration becomes complicated and the cost increases.
In the IC, the dimensions of the pins are properly controlled.
Since the outer shape of the package portion has poor dimensional accuracy, there is a problem that the measurement accuracy of the center of gravity and the rotation angle is reduced.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and can measure the position and orientation of a component at a high speed with a simple circuit configuration, and at a high precision without being affected by the accuracy of the external dimensions of the package. It is an object of the present invention to provide a measuring device for measuring the position and the like of a part capable of measuring the position and orientation of the part.

[0006]

SUMMARY OF THE INVENTION The present invention relates to a component position measuring device for capturing a component having a plurality of pins and measuring a component position and orientation from an input image of the component. Means for processing to generate a binary image;
After scanning the value image and detecting the tip position of any pin,
Means for measuring the positional relationship with other pixels based on the tip position to determine whether the pin is an end pin.

[0007]

The position of an end pin is detected by determining whether or not an arbitrary pin detected by scanning a binary image is an end pin.
From the position of each end pin, the center of gravity and main shaft angle of the component can be easily measured. Further, since the measurement is not affected by the dimensional accuracy of the outer shape of the package portion, the measurement accuracy of the center of gravity and the rotation angle does not decrease.

[0008]

FIG. 1 shows an embodiment of an apparatus for measuring the position of parts 1 according to an embodiment of the present invention. In the figure, 2 is I
C, a plurality of pins 4 protrude along the outer periphery of the rectangular package portion 3. The IC 2 is located on the tray 5 and the suction portion 6 of the chip mounter
2 is sucked up, transported to the position of the printed circuit board 7, and mounted at a predetermined position on the printed circuit board 7.

An observation position is set during the transportation of the IC2,
The measuring device 1 such as a component position is installed at the observation position, and it is inspected whether the holding position and the posture of the IC 2 by the suction unit 6 are appropriate. If the holding posture is inclined, the suction unit 6 is rotated in the direction shown by the arrow a by the inclination of the rotation angle to correct the holding posture, and if the holding position is displaced from the reference position, The mounting position on the printed circuit board 7 is corrected by the positional shift amount.

The measuring device 1 for measuring the component position and the like is constituted by a camera 9 and an image processing device 10. The camera 9 is arranged below the observation position and images the IC 2 from below. Although not shown, it is a matter of course that an illumination device is provided above or below the observation position to perform transmission illumination or reflection illumination.

FIG. 2 exemplifies a circuit configuration of the image processing apparatus 10. The image input unit 11 receives an analog image signal from the camera 9, binarizes the image signal, and outputs the binary image to the image memory 12. The image memory 12 stores the input image data of the binary image in units of one pixel. The character memory 16 stores font data for characters to be displayed on the video monitor 14. The image output unit 13 converts the image data output from the image memory 12 and the character memory 16 into a signal of an analog amount, and sends an image signal for one screen to the video monitor 14. The video monitor 14 displays an input image, a calculation result, and the like based on an image signal from the image output unit 13.

The image memory 12 and the character memory 16 are connected to an address / data bus 17, and the address / data bus 17 has a CPU 18, a ROM 19, and a RAM.
20 and the I / O port 21 are connected to form a microcomputer. In this microcomputer, the CPU 18 decodes and executes a program stored in a ROM 19, reads and writes data from and to a RAM 20, and measures a holding position and a holding posture of the IC 2, for example.
Execute various image processing. The timing control unit 15
The image input unit 11 and the image memory 1 are linked with the CPU 18.
2. It outputs a timing signal for controlling the input and output of data in the image output unit 13 and the character memory 16.

FIG. 3 shows a method of measuring the tip position of the end pin used for measuring the holding position and holding posture of the IC 2. In the figure. Reference numeral 22 denotes an IC stored in the image memory 12.
In the figure, a hatched portion is a black pixel, and the other portion is a white pixel. The binary image 22 is scanned in the direction indicated by the arrow b in the figure to detect a black pixel at the tip position P0 (X0, Y0) of an arbitrary pin 4a, and then several pixels d (for example, from the tip position P0) The horizontal scanning line lowered by d = 3 pixels is scanned, and the first black pixel position P1 (X1,
Y1) is detected. At this time, if the difference L (L = X1-X0) between the X coordinate values of the positions P1 and P0 is smaller than a predetermined value (for example, 3), it is determined that the tip position P0 is the tip position P of the end pin 4c. If the value is equal to or more than the predetermined value,
It is determined that the pin is other than the pin 4b, and the detection of the end pin is continued.

FIG. 4 shows a procedure for measuring the holding position and holding posture of the IC 2 by the CPU 18. In step 1 (shown as “ST1” in the figure) of the figure, the method shown in FIG. 3 is executed to measure the tip positions of the end pins on any side of the IC2. In the case of the IC 2 of this embodiment, since a plurality of pins 4 are provided for four sides, the tip positions of the pins at both ends of the four sides (total of eight places) are measured. Needless to say, the direction of the scanning is changed according to the end pin.

When the tip positions of all the end pins are measured,
The determination in step 2 becomes “YES”, and the center of gravity position is calculated using the coordinates of the tip positions of all the end pins (step 3).
And the rotation angle calculation (step 4). In this case, any method may be used to calculate the position of the center of gravity and the rotation angle, but here, the average value of the coordinates of the end positions of all the end pins is determined as the center of gravity, and the distance between the ends of the left and right end pins is calculated. The average value of the inclination of the connecting straight line is obtained as the rotation angle.

FIG. 5 shows the procedure for measuring the position of the tip of the end pin by the CPU 18, that is, the details of step 1 in FIG. 4. The procedure in FIG. 5 will be described in detail with reference to FIG.

First, in step 1 of FIG.
Numeral 8 scans the binary image 22 stored in the image memory 12 in the direction shown by the arrow b in FIG. 3, and detects the first black pixel as the tip position P0 of an arbitrary pin 4a in step 2. The coordinates of this tip position P0 are (X0, Y0),
It is stored in the RAM 20 (step 3).

In the next step 4, the CPU 18 determines that Y0 + 3
The horizontal scanning line is scanned in the same direction as described above, and at step 5, the position P1 of the first black pixel is detected.
The coordinates of this position P1 are defined as (X1, Y1), and the RAM 20
(Step 6).

Next, at step 7, the CPU 18 determines a distance L (L = X1-X) in the X direction between the positions P1 and P0.
0), and depending on whether the value is smaller than 3, P
It is determined whether 1 and P0 are on the end pin 4c (step 8). In the example of FIG. 3, since the distance L is 3 or more, the determination in step 8 is “NO”, and then in step 9 the CPU 18 scans the horizontal scanning line Y0 + 1 in the same direction as described above. In step 10, the first black pixel is detected as the tip position P0 of a new arbitrary pin 4a (step 3).

Hereinafter, in the process of executing the same procedure, if the judgment in step 8 becomes "YES", P1 and P1
0 is the position on the end pin 4c,
1 and the tip position P0 (X
(0, Y0) is registered in the RAM 20 as the tip position P (X, Y) of the end pin 4c.

[0021]

As described above, according to the present invention, when a component having a plurality of pins is imaged and the component position and orientation are measured from the input image, a binary image of the input image is scanned and an arbitrary pin is scanned. After detecting the tip position of the component, the positional relationship with other pixels is measured based on the tip position to determine whether or not the pin is an end pin. Position and orientation can be easily measured. Further, since there is no influence of the dimensional accuracy of the external shape of the package portion of the component, the measurement accuracy of the position and orientation of the component does not decrease.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing an implementation state of a component position etc. measuring device according to an embodiment of the present invention.

FIG. 2 is a block diagram illustrating a circuit configuration of the image processing apparatus.

FIG. 3 is an explanatory diagram showing a method of measuring the tip position of an end pin.

FIG. 4 is a flowchart showing a procedure for measuring an IC holding position and holding posture.

FIG. 5 is a flowchart showing a procedure for measuring a tip position of an end pin.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Component position measuring device 2 IC 9 Camera 10 Image processing device 11 Image input part 18 CPU

Claims (1)

(57) [Claims] An apparatus for measuring a component position and orientation from an input image of a component having a plurality of pins by capturing an image of the component, wherein the input image is binarized to generate a binary image Means for scanning the binary image and detecting the tip position of an arbitrary pin, and measuring the positional relationship with other pixels based on the tip position to determine whether the pin is an end pin. A part position measuring device comprising: means for determining.