JPS6398187A - Method of detecting position of reference mark of multilayer printed board - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Industrial field of application The present invention relates to a method for detecting the position of a blockage mark on a one-to-five layer printed circuit board. (b) Conventional technology Holes for wiring in a multilayer printed circuit board Holes are generally drilled using a multi-axis drill. In order to position the multilayer printed circuit board with respect to the drill, the reference hole of the multilayer printed circuit board is fitted onto the guide pin of the multi-axis drilling machine. Therefore, the reference hole must be accurately provided at a predetermined position on the S II printed circuit board. For this purpose, a device is used that detects a reference mark (copper mark) provided in advance on a multilayer printed circuit board and drills at the detected position. However, in order to detect the reference mark on a multilayer printed circuit board that has a copper foil layer on the surface and a reference mark on the inner layer, image processing using X-rays is required to locate the center of the reference mark. There is no other way but to obtain the desired results, the equipment is expensive, and there are legal regulations regarding X-ray plates, so it cannot be easily performed. In order to solve this problem, the applicant first filed a patent application in 1986-23.
889 was filed. This technology involves providing in advance a reference copper foil wire in a predetermined relative positional relationship with the reference mark on the same layer as the blocking mark on the multilayer printed circuit board.
First detect the position of the Buddhist monk copper foil wire by moving the eddy current position sensor, and then move the eddy current position sensor to the reference mark based on the relative position of the reference copper foil wire and the reference mark. The position is detected by moving towards the target.

(c) Problems to be solved by the invention However, this method requires two operations: detecting the position of the reference copper foil wire and detecting the position of the reference mark, which inevitably reduces the detection speed. There was a drawback. The present invention aims to solve these problems.

(d) Means for solving the problem The present invention stores in advance an approximate value from the end face of a multilayer printed circuit board to the position of a reference mark, and positions an eddy current position sensor at this approximate position to perform detection operation. The above problems are solved by starting . That is, the method for detecting the position of a reference mark on a multilayer printed circuit board of the present invention is as follows:
In a method for detecting the position of a reference mark on a multilayer printed circuit board in which another copper foil layer is provided on a layer on which a copper plugging mark has been provided in advance, The distance to the current position is memorized in advance, and the eddy current position sensor is positioned above this Shobara position to start the detection operation of the reference mark. The size of the reference mark is selected so that the coordinates at which this eddy current type position sensor is located are always located within the reference mark.

(Position) An eddy current type position sensor is positioned above the pre-stored coordinates from one end of the S-layer printed circuit board to the position where the reference mark is provided.

The eddy current position sensor is located at a certain coordinate within the reference mark according to the processing error of the multilayer printed circuit board.

From this state, move the eddy current position sensor horizontally (X).
The eddy current position sensor detects the position of one end of the reference mark from the change in output voltage or current caused by passing over the 'j5Q mark, and then returns the overcurrent position sensor in the opposite direction. , and detect the other end position in the same way.

Find the correct center distance in the X direction from these two values, and move the eddy current position sensor to this position.6 Next, from this point, move the eddy current position sensor 4i ((Y)
The center point of the reference mark can be determined by moving the reference mark in the direction and performing one detection movement to determine the correct center distance in the Y direction.

Embodiments Embodiments of the present invention will now be described in detail with reference to FIGS. 1 to 6 of the accompanying drawings.

FIGS. 1 and 2 show a reference hole machining apparatus for a multilayer printed circuit board for carrying out the method of the present invention. A drill head 10 provided with an eddy current position sensor 6 and a drill 8 includes:
It is attached to a table 14 movable in the X direction by a servo motor 12, and this table 14 is further provided on a table 18 movable in the Y direction perpendicular to the X direction by a servo motor 16. The operation of the servo motor 12 and the servo motor 16 is controlled by a controller 20, and the operation of the servo motor 12 and the servo motor 16 is controlled by a controller 20.
, i.e., the X direction and Y direction of the drill head 10
A signal corresponding to the directional coordinates is detected by, for example, a pulse detector provided thereon, and is input to the controller 20. In addition to inputting the detection signal of the eddy current position sensor 6 to the controller 20, the average value signal (X-direction data and Y-direction data) of the measured values from the end face of a large number of multilayer printed circuit boards to the center position of the copper mark 4 (two types of signals) are also stored.

Next, the method of the present invention will be explained. Multilayer printed circuit board 2
For example, it has a four-layer structure, with the top and bottom outermost layers having a thickness of 2.
It is a copper foil layer with a thickness of approximately 0μ, and a circular copper mark 4 serving as a reference mark is provided on the second layer from the top. Each layer is partitioned by a blibrave 2e. Therefore, the copper mark 4 on the second layer from the top is not visible from the outside. Multi-layer printed circuit board 1/board 2 requires cutting and propagation if many pieces are taken out, and if one piece is taken out, it is necessary to remove the protruding part of the break break 2e and make the dimensions uniform. In any case, the radix end face is cut, but as mentioned above, the base mark cannot be seen visually, so the dimension from the center of the reference mark to the radix end face cannot be accurately obtained. There is.

In advance, the radix end face 2a1.2 of the multilayer printed circuit board 2
The respective distances from b1 to the center of the use mark 4 (<2rUIJ) are stored in the il controller 20.

The virtual end face based on this average value is represented by the end face 2a in the X-axis direction and the end face 2b in the Y-axis direction in FIG. The size of the copper mark 4 is selected so as to fit inside the copper mark 4.

With the multilayer printed circuit board 2 installed on a predetermined processing table,
The eddy current position sensor 6 is driven on a coordinate 4Z based on two average position signals from the controller 2o. This coordinate 4z is within the circle of the copper mark 4. From this state, place the overcurrent type position sensor 6 on the end surface 2al of the multilayer printed circuit board 2.
When the eddy current type position sensor 6 is moved in the direction (X direction) that intersects the reference mark 4, the output current of the eddy current position sensor 6 changes as shown in FIG. Servo motor when the current rises to a predetermined value (that is, this corresponds to 4xl)] 2 or +
The coordinate value X1 indicated by the pulse signal j-, is stored in the controller 20. In addition, the output current of the eddy current position sensor C) when moving rightward in Fig. 4 through point 4x2 also changes as shown in No. 617I. is stored. In the controller 20, X-(x
l + x2) / 2 is calculated by n, and this X is jll
This indicates the coordinate value of the center position of the mark 4 in the X direction. Next, turn the servo motor 16 to l? The eddy current type position sensor 6 is moved back and forth in the Y direction, and the center position of the copper mark 4 in the Y direction is calculated by the same operation as above. This means that the center position of the copper mark 4 has been calculated. Next, the servo motor 12 and the servo motor 16
is activated to move the drill 8 to this center position.

That is, from the state where the eddy current type position sensor 6 coincides with the center position of the detected copper mark 4, the servo motor 12 is operated to move the drill head 8 by the distance MR between the eddy current type position sensor 6 and the drill 8. The state will be as follows. Thereby, the drill 8 is aligned with the center position of the copper mark 4.

Next, the drill 8 is lowered and the reference hole is machined. In this way, the base hole is precisely machined in the center of the copper mark 4. Since there is generally a plurality of reference holes, for example, by storing coordinate values from the first reference hole in the controller 20, it is possible to perform the following processing efficiently.

(G) Effects of the Invention L'l As explained above, according to the present invention, the coordinates at which the eddy current position sensor 6 is initially located are always within the circle of the copper mark, so that it can be moved over a short distance. The center of the copper mark can be detected, and the center position of the copper mark, which cannot be visually confirmed, can be quickly detected, improving work efficiency.

[Brief explanation of the drawing]

Figure 1 is a plan view showing the reference hole processing device, Figure 2 is a view seen in the +1 direction of the arrow in Figure 1, Figure 3 is a diagram showing the relationship between the end face of a multilayer printed circuit board and the reference hole, and Figure 4. Figures 5 and 6 show the miracle of wave marks and eddy current position sensors.
(21 is a diagram showing changes in the output current of the eddy current position sensor. 2...Multilayer printed circuit board, 4...Copper mark, 6.
・Eddy current 2nd position sensor, 8...drill, 10...
Drill head, 12... Servo motor, 14... Table, 16... Servo motor, 18... Table, 20... Controller. Figure 2: 4x2 cell position

Claims (1)

[Claims] 1. In a method for detecting the position of a reference mark on a multilayer printed circuit board in which another copper foil layer is provided on a layer on which a copper reference mark is previously provided, The multilayer printed circuit board is characterized in that the distance from to the position where the reference mark is provided is stored in advance, and an eddy current type position sensor is positioned above this position to start the detection operation of the reference mark. Reference mark position detection method. 2. The size of the reference mark is selected such that the pre-stored coordinates are always located within the reference mark, the reference mark position of the multilayer printed circuit board according to claim 1 Detection method.