JPS59180307A - Automatic positioning method - Google Patents

Abstract

PURPOSE:To realize automatic positioning which relieves the restrictions of lighting without any movement between a positioned and a positioning body, by calculating the amount of a pattern indicating the degree of positioning from image pattern data on both positioned and positioning bodies. CONSTITUTION:Images of the area including the pad 3 of a printed wiring board 2 and the area including the lead 6 of parts 5 are picked up by TV cameras 1 and 4 and binary-coded original image pattern data are written in RAMs 9 and 10 by a write signal on a line 11. The original image pattern data are read out of the RAMs 9 and 10 while a predetermined offset is given between the both to obtain image pattern data. Then, the coefficient of evaluation of the offset is calculated while the offset is varied and inputted to a microcomputer 17, which obtains an evaluation coefficient graph shown in a figure by using those values to perform the positioning by using such an offset that the coefficient of evaluation is minimized.

Description

Detailed Description of the Invention (a) Technical Field of the Invention The present invention relates to an automatic alignment method, in particular a method for aligning an object to be aligned and an object to be aligned without moving the object for alignment. The present invention relates to an automatic positioning method that incorporates a unique technique into the acquisition and processing of image pattern data for both of the above, and generates a signal used for positioning the above.

(0) Background of the Technology In various manufacturing fields, it is necessary to align an object to be aligned and an object to be aligned. For example, in the manufacture of circuit boards, it is necessary to align the leads of a semiconductor integrated circuit package, which serve as a matching material, to designated locations of wiring on a printed wiring board, which serves as a matching material.

As a positioning method in such a case, there is a technique of acquiring the pattern of the area including the above-mentioned I-position points and leads, and performing pattern matching to perform positioning, but this technique is still difficult to use. There is a problem to be solved, and there is a technique developed by the applicant's inventors to solve this problem, but this technique requires movement, requires time for alignment, and
There are problems such as lighting restrictions.

(c) Prior art and problems The above-mentioned automatic positioning by the inventor of the present applicant (Japanese Patent Laid-Open No. 55
-88347) is as follows. First, as shown in Figure 1, an image pattern is taken from a predetermined wiring location C that is soldered to the lead of a semiconductor integrated circuit board on a printed circuit board using a sensor camera a, and the binarized pattern is converted into a It is retained as an image pattern for use. Next, as shown in FIG. 2, the leads e of the semiconductor package d are positioned on the printed circuit board, the area including these predetermined wiring locations C and the leads e is imaged by the sensor camera a, and the image is captured. The binarized pattern of the pattern is used as an image pattern for scanning.

For these patterns, we introduce an evaluation coefficient F that is limited as follows, and perform seven cages d until the value of this F becomes the minimum, that is, until F in the graph of Figure 3 reaches the minimum value. Calculation is performed each time the FO is moved. Here, F is F = Σ(Mn-3n) n ''1, m is the total number of focuses in the data acquisition area, h is the n-th bit in the mask/image pattern, and there is no board wiring. The bit Sn is the n-th bit in the scan image pattern, and is a bit that indicates the presence of board wiring or package leads.

When such processing is repeated and the above-mentioned value of F becomes the minimum value, the alignment between the above-mentioned predetermined wiring location and +C is completed.

This type of processing not only does not require high mechanical precision, but also simplifies the recognition logic circuit, avoids problems caused by board distortion, provides versatility, and eliminates the problem of bending of the lead F. However, as mentioned above, it requires repeated movement until positioning, which increases the time required, and there are lighting restrictions such as the use of reflected light.

(2) Purpose of the Invention The present invention was devised in view of the above-mentioned drawbacks of the prior art, and its purpose is to obtain a signal for use in positioning between the objects to be aligned and the objects to be aligned. An object of the present invention is to provide an automatic positioning method that does not require any movement and can also alleviate lighting restrictions.

(,→Structure of the InventionAnd, this purpose is to acquire image pattern data of an object to be aligned and an object to be aligned by giving a predetermined offset amount between these two image patterns, and obtain the image pattern data of both image patterns. A pattern amount representing the degree of alignment between the object to be aligned and the object to be aligned is calculated from the offset amount that minimizes the pattern amount. This is achieved by each time a signal is generated.

(→Embodiments of the Invention Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

4 and 5 show an embodiment of the present invention.

In FIG. 4, ζ, 1 is a rv camera that images the area including the pad 3 of the printed wiring board 2, which is the object to be aligned, and 4 is the area including the lead 6 of the component 5, which is the object to be aligned. This is a T'V camera that takes images.

The region including the REIT 6 is illuminated by a lighting device 8 via a light diffusing plate 7.

The outputs of these TV cameras 1 and 4 are as shown in FIG.
Each corresponding random access memory (hereinafter referred to as RA)
It is abbreviated as M. )9.10-\The binarized image pattern data from the connected TV cameras 1 and 4 are recorded in the corresponding RAM9.10 (as indicated by q. Line 1
1 is read/? A. It is a complex control line.

The RAM 10 is read out by an address generated from the address generator 12, and the RAM 9 is read out by an address from an address offset circuit 13 which gives a predetermined offset amount to the address from the address generator 12 and outputs it. . Line 14 is an offset input line.

The readout output of RAM 9.10 is connected to the evaluation coefficient logic circuit 15, and the output of the circuit 14 is connected to the counter 16.
．． The evaluation coefficient F explained in the section of the prior art and problems is outputted from each counter 16. This output is connected to a signal processing circuit, for example, a microcomputer 17.

Further, the off-cent human power lineman 4 is connected to the microcomputer 17. The output line 18 from the microcomputer 7 is connected to a drive device (not shown). This driving device is a device for driving the printed wiring board 2 or the component 5 to align them.

Next, the operation of the above-mentioned configuration device will be explained.

The area including the pad 3 of the printed wiring board 2 is imaged by the TV camera 1, and the 2-sulfurized raw image pattern data is set to the embedding mode by the line 11''2. Written to M9. In parallel with this or before and after, the part 5 is detected by the i” V camera 4.
The area including the lead 6 is imaged, and the binarized raw image pattern data is set to the write mode by the write signal on the line 11 and written into the RAM 10. The data written to the RAM 9.10 in this way is, for example, one screen worth.

In this way, data is read out from the RAM 9.10 by giving a predetermined offset amount between the image pattern data of these parts, and image pattern data for obtaining evaluation coefficients is obtained.

At this time, the off-center value is given via line 14 as an address offset time i/813-\.

Each term 1n-3n of the above-mentioned 64' valence coefficient in the off-set data used to read out the data is calculated sequentially, and the sum of the terms 1n-3n of the 64' valence coefficient Ffl used to read the data is calculated, and the summation 1ruji evaluation coefficient F= The output signal is sent to the microcomputer 17.

Calculation of such evaluation coefficient F is performed using offcent human power line ■4
The evaluation coefficient for each offset amount is input to the microcomputer 17 while changing the above offset +-i.

Upon receiving these inputs, the microcomputer 17 uses these values to obtain an evaluation coefficient graph as shown in FIG. 3 above. Then, using the offset i that minimizes the evaluation coefficient in this graph, the microcomputer 17 sends a drive amount determined by this offset amount onto a line 18, and a drive device (not shown) is used to drive the substrate 12 or The component 5 is driven to bring about alignment between the pad 3 of the board 12 and the sword 6 of the component 5.

In the above embodiment, two RAMs are used, but the image pattern data of one may be raw data from the RV camera, and the image pattern data of the other may be obtained from the memory. It is also possible to obtain the same result as described above by not using any memory at all and by shifting the timing of the two 'r' v cameras by an appropriate amount.Also, as shown in FIG. 2 and the component 5 through a half mirror 19, the pattern data can be obtained by one TV camera 20. In this case, the imaging of the substrate 2 and the component 5 is performed alternatively.

(G) Effects of the Invention As is clear from the above description, according to the present invention, ■ positioning between the object to be aligned and the object to be aligned without requiring relative movement between the two; Since the amount of patterns representing the degree of alignment can be minimized, the time required for alignment can be shortened.

(2) Since transmitted light can also be used, restrictions on illumination can be relaxed, and while inheriting the effects of the invention disclosed in JP-A-55-88347, it also has even greater effects.

[Brief explanation of drawings]

1 and 2 are diagrams for explaining the acquisition of an image pattern for a mask and an image pattern for scanning, respectively; FIG. 3 is an evaluation coefficient graph; and FIGS. A diagram showing an example, FIG. 6 is a diagram showing a modification of the image capturing system. In the figure, 1 and 4 are TV cameras, 2 is a printed wiring board, and 3
ba band, 5 ba parts, 6 lead, 9゜10 RAM,
1.2 is an address generation circuit, 13 is an address offset circuit, 15 is an evaluation coefficient logic circuit, 16 is a counter, j7
is a microcomputer. Fig. 1 Fig. 2 ψ Ka F giant S

Claims (1)

[Claims] (11 Image pattern data of the object to be aligned and the object to be aligned are acquired by giving a predetermined offset amount between these two image patterns, Determining the pattern amount without expressing the degree of alignment between the object to be aligned and the object to be aligned,
An automatic positioning method characterized in that a signal used for positioning the object to be aligned and the object to be aligned is generated from an offset amount that minimizes the pattern amount. (2) Is the evaluation coefficient 1 to minimize the above pattern amount? F−Σ(πn·5n) 1′l=. (However, in the above formula, m is the total number of bits in the predetermined data acquisition area, M n is the nth bit of the image pattern data of the object to be aligned, and it is assumed that the object to be aligned does not exist. The hint Sn is the nth bit of the composite image data of the object to be aligned and the object to be aligned, which is a bit indicating the existence of the object to be aligned or the object to be aligned. 2. The automatic positioning method according to claim 1, wherein the evaluation coefficient is minimized. (3) The automatic positioning method according to claim 1 or 2, characterized in that the offset amount is generated by address syncing of the memory. (4) The automatic positioning method according to claim 1 or 2, characterized in that the offset amount is generated by shifting the timing of the imaging system. (5) Claim 1 or 2, characterized in that the offset amount is caused by storing data from one imaging system and directly using data from the other imaging system. Automatic alignment method described in section.