JPH04340799A - Printed board and position corrector thereof - Google Patents

Abstract

PURPOSE:To effectively correct a position. CONSTITUTION:In order to provide a position correcting pattern 2 on a printed board 1, many position correcting marks 2a to be used at the time of correcting a normal position, and many substitute correcting marks 2b used instead when the marks 2a are not correctly recognized are provided. The position correction can be substituted to enhance reliability of the position correction.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printed circuit board and a device for correcting its position, and for example, to an improvement in an electronic component mounting device and an inspection device for the state of electronic component mounting on a printed circuit board.

0002

2. Description of the Related Art FIG. 5 shows a printed circuit board used in a conventional position correction device. In the figure, 1 is a printed circuit board, 21 and 22 are position correction patterns, 4 is a mounting component,
3 is a reference hole for positioning. Further, FIG. 6 is a diagram for explaining the case where the printed circuit board 1 is transported to the position correction device, in which 1, 3, and 4 are the same as in FIG. 5, and 5 is a diagram provided on both sides of the printed circuit board 1. This is the transportation area. Other numbers are specific examples of dimensions, and the unit is mm.

Next, the operation will be explained. The printed circuit board 1 transported to the mounting or inspection station is positioned using the external reference or the positioning reference hole 3.
As it is, the positioning accuracy required for high-density mounting components 4 and inspection cannot be obtained. For this purpose, a television camera (CCD camera) provided on the XY table detects two position correction patterns 21 and 22 provided on the printed circuit board.
Detects, performs image processing and calculates the pattern position,
Correct the misalignment of the printed circuit board. Image processing involves binarizing the video signal and importing it into the image memory to calculate the center of the pattern.The position correction pattern is a recognition circular or triangular mark with a diameter of about 1 to 2 mm called an eye mark or target mark. It is. Then, for example, by moving the camera, the center of gravity of this mark is measured based on the vertical and horizontal projection pattern and the threshold value in the window as shown in FIG. If the actual positions of these two points can be measured, the other points (component mounting positions) can be calculated mathematically.

0004

[Problems to be Solved by the Invention] The conventional printed circuit board and its position correction device are configured as described above, so it is good in cases where measurement is relatively easy, but in special cases, for example, (a) circuit pattern (b) Items with solder plating and extremely uneven surfaces (b) Items with other patterns surrounding the eye mark (c) Items with an eye mark that has changed into a special shape. Because the conditions vary greatly depending on the printed circuit board, it is often impossible to deal with it using only hardware methods, such as devising ways to apply filtered lighting. Furthermore, even software such as an automatic threshold function or a window function that allows the recognition range to be set to a free shape may not be able to handle this problem. On the other hand, with the recent demand for high-density packaging, wiring patterns with a minimum line width of 200 μm or less are being put into practical use, and the lead pitch of mounted components is also generally 0.4 mm or less. However, as shown in Figure 7, for example, the amount of warpage and expansion/contraction of the base material that occurs due to changes in the printed circuit board environment (temperature, humidity) is large (0.1% of the total length for flexible boards), making it difficult to perform local correction. There is a need.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a printed circuit board and a position correction device thereof that can reliably correct the position.

[0006]

[Means for Solving the Problems] A printed circuit board according to a first aspect of the invention is provided with a plurality of correction marks, and has the following requirements. (a) A position correction mark provided at a predetermined position on the printed circuit board to correct the position of the printed circuit board; (b) At least one position correction mark provided at a different position from the above position correction mark to replace the position correction mark. Alternative correction mark.

The printed circuit board position correction device according to the second invention corrects the position of the printed circuit board according to the first invention, and has the following elements. (a) Position correction means for correcting the position of the printed circuit board using position correction marks on the printed circuit board; (b) Alternative correction means for correcting the position of the printed circuit board using at least one of alternative correction marks for the printed circuit board; (c)
) Switching means for switching between the position correction means and the alternative correction means under predetermined conditions.

[0008]

[Operation] The printed circuit board and its position correction device according to the present invention are capable of correcting even if the position correction mark is unrecognizable by using the substitute correction mark, since a plurality of substitute correction marks are provided. Furthermore, since correction can be performed using any position correction mark or substitute correction mark close to the mounted component or the inspected component, the position correction accuracy is increased.

[0009]

【Example】

Example 1. An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, 1 is a printed circuit board, 2 is a position correction pattern, 3 is a reference hole, and 4 is a mounted component. 2a is a position correction mark, and 2b is an alternative correction mark. Both of these correction marks 2a and 2b are cross-shaped pattern intersections arranged on the correction pattern 2 at predetermined intervals. FIG. 2 is an enlarged view of the position correction pattern 2 and a binarized image of the correction mark picked up by the window. FIG. 3 is a diagram showing an embodiment of the printed circuit board position correction device according to the present invention, in which 6 is a television camera, 7 is an offset gain control, 8 is an amplifier, 9 is an A/D converter, and 10 is a video camera. 11 is a grayscale screen, 12 is a binary screen, 13 is an overlay screen, 14 is a position correction means, 15 is an alternative correction means, 16 is a switching means, 17 is a monitor TV, 18 is a D/A converter, 19 is a A CPU/memory, 20 various I/Os, and 21 an I/O channel bus.

Next, the operation will be explained. First, the operation of the position correction means 14 will be explained. The printed circuit board 1 transported to the mounting or inspection station is positioned using the external reference or the positioning reference hole 3, but the accuracy required for the mounted component or the inspected component 4 cannot be obtained as it is. Therefore, the two diagonal points 2a of the position correction pattern 2 provided on the printed circuit board 1 are detected by the TV camera 6 mounted on the XY table, the pattern position is calculated, and the positional deviation of the printed circuit board is detected. to correct. In image processing, the video signal is binarized and loaded into an image memory such as a binary screen 12, and pattern intersection points are determined based on an overlay screen 13 or the like. If the actual positions of two points can be measured, the other points can be calculated mathematically, so corrections can be made.

Next, the operation of the alternative correction means 15 will be explained. Since a large number of alternative correction marks 2b of the position correction pattern 2 are provided around the printed circuit board 1, even if an error in image recognition occurs with the position correction mark 2a, it can be replaced with any of the alternative correction marks 2b. For example, the following method can be used to determine the alternative correction mark 2b for substitution. (a) The alternative correction marks next to the position correction mark 2a are selected as alternative candidates in order. (b) The alternative correction marks that are farthest from the position correction mark 2a are selected as alternative candidates in order. This is because it is thought that the same cause as the error in image recognition of the position correction mark 2a is least likely to occur at the farthest location. (c) Although the position correction mark 2a is usually provided on the object line in many cases, an alternative correction mark on the other diagonal line is used. (d) Randomly select alternative correction marks.

Furthermore, since a large number of alternative correction marks 2b of the position correction pattern 2 are provided around the printed circuit board 1, the position can be corrected using alternative correction marks close to the X and Y coordinates of the mounted component or the inspected component 4. Can be done.

Next, the switching means 16 will be explained. The switching means 16 performs a switching operation from the position correction means 14 to the alternative correction means 15, for example, in the following cases. (a) When the position correction means 14 determines that the position correction mark 2a cannot be recognized, (b) When the recognized position of the position correction mark 2a is not within a pre-estimated tolerance range, (c)
When there is an instruction from outside to use an alternative correction mark. For example, an alternative designation is issued from the outside when a manual setting is made in advance, or when a physical change in the shape, warpage, expansion/contraction, etc. of the printed circuit board is discovered during the printed circuit board manufacturing process. (d) When mounting a component that requires highly accurate position correction, an alternative correction mark closest to the mounting position is used.

Example 2. In the above embodiment, the position correction pattern 2 is provided around the printed circuit board 1, but in the case of a multi-panel board or the like, it may be provided inside the multi-panel board 1a as shown in FIG.

Further, in the above embodiment, the case where the position correction pattern 2 is specially provided is shown, but it is also possible to use a highly accurate wiring pattern as the position correction pattern and use pattern intersections that are easy to perform image processing. .

[0016]

[Effects of the Invention] As described above, according to the present invention, since an alternative mark is provided in the position correction pattern, a retry function for the position correction function can be added, and a highly reliable device can be obtained. Alternatively, correction can be made at a point close to the inspected part, which has the effect of obtaining highly accurate results.

[Brief explanation of drawings]

FIG. 1 is a diagram showing a position correction pattern of a printed circuit board according to an embodiment of the present invention.

FIG. 2 is a diagram for explaining a position correction mark/alternative correction mark according to the present invention.

FIG. 3 is a configuration diagram of a printed circuit board position correction device according to an embodiment of the present invention.

FIG. 4 is a diagram showing a position correction pattern for a printed circuit board according to another embodiment of the present invention.

FIG. 5 is a diagram showing a conventional printed circuit board.

FIG. 6 is a diagram for explaining a position correction operation of a printed circuit board.

FIG. 7 is a diagram showing an example of a change in the shape of a printed circuit board.

[Explanation of symbols]

1 Printed circuit board 1a Multi-sided board 2 Position correction pattern 2a Position correction mark 2b Alternative correction mark 3 Reference hole 4 Mounted parts/inspection parts

Claims (2)

[Claims] Claim 1: A printed circuit board (a) having the following elements:
) A position correction mark provided at a predetermined position on the printed circuit board to correct the position of the printed circuit board, (b)
At least one alternative correction mark provided at a different position from the position correction mark to replace the position correction mark. 2. A position correction device (a) having the following elements and correcting the position of a printed circuit board according to claim 1:
position correction means for correcting the position of the printed circuit board using position correction marks on the printed circuit board; (b) alternative correction means for correcting the position of the printed circuit board using at least one of alternative correction marks on the printed circuit board; (c) the above-mentioned position correction A switching means for switching between the means and the alternative correction means under predetermined conditions.