JPH0657381B2 - Correction method of hole processing position - Google Patents

Description

Detailed Description of the Invention [Industrial applications]

The present invention relates to a method for correcting a hole processing position when processing a plurality of holes, such as reference holes provided on a multilayer wiring board, which are required to have high relative position accuracy.

[Prior art]

When providing a reference hole in a work material such as a multilayer wiring board, the position of the reference hole is not determined as an absolute position, but relative to the wiring pattern formed in the work material. It is decided by the proper position. For this reason, when forming multiple reference holes in such a workpiece, it is possible to make markings at the positions where the reference holes should be provided when forming the wiring pattern and then make holes based on these markings. Be seen. However, since there is inevitably an error in the pitch dimension between a plurality of markings made in this way, when making a hole, correction must be performed based on the marking position. FIG. 8 shows an example of an apparatus for this purpose. Reference numeral 2 in the drawing denotes a camera, which is mounted on the slider 30 of the moving device 3. The slider 30 is adapted to move by rotation of the feed screw 31 by a motor 33 by being screwed with the feed screw 31 and engaged with the guide shaft 32. Reference numeral 4 in the figure denotes an encoder for reading the position of the camera 2. Now, in the case of the above-mentioned conventional example, the relative positional accuracy of the marks 11 and 12 provided on the workpiece 1 is first one of the marks 1.
1 is imaged, the position of the camera 2 at that time is stored, and then the camera 2 is moved to image the other mark 12. During this time, it is determined by obtaining pick dimension data between the marks 11 and 12 from the movement amount of the camera 2 obtained from the encoder 4 and the image pickup positions of the marks 11 and 12 in the field of view of the camera 2, and this is determined. Correct the position to make the original hole.

[Problems to be Solved by the Invention]

However, the above method has the following problems. That is, since it is affected by the accuracy of the feed screw 31 and the encoder 4, these must be made extremely highly accurate, which increases the equipment cost and the operating environment of these equipments. It should be done in a way that does not hurt. Further, the straightness of the camera 2 with respect to the work material 1 may change during movement. In such a case, as shown in FIG. 10, the distance from the position detection center of the camera 2 to the work material 1 is changed. If l and the angle error are θ, a detection error ε≈l · θ occurs. As shown in FIG. 9, the mark 1 is moved by moving the workpiece 1 instead of moving the camera 2 and detecting the feed amount of the workpiece 1 instead of the movement amount of the camera 2.
There is also a system in which the relative position accuracy of 1 and 12 is detected, but in this case as well, there is the same problem in the above case regarding the accuracy of the feed member of the workpiece 1 and the encoder for detecting the feed amount. In addition, the flatness variation on the workpiece 1 side causes the same problem as when the straightness of the camera 2 changes. The present invention has been made in view of such a point, and its object is to enable high-accuracy position measurement of a mark even though the equipment side does not require so much accuracy. The present invention provides a method for correcting a hole drilling position that enables accurate setting of the hole drilling position.

[Means for Solving the Problems]

Therefore, the present invention is to provide a predetermined point in each screen field of view in a plurality of cameras which are installed at intervals substantially corresponding to the intervals of a plurality of marks for indicating a drilling position provided on a work material. Is determined by imaging the reference scale with these cameras, and from the position coordinates of the marks of the workpiece to be imaged by these cameras with respect to the predetermined points in the screen field of view and the intervals between the predetermined points, The feature is that the distance between the marks is calculated, and the drilling position is corrected from the deviation between the design dimension between the marks and the calculated distance between the marks. [Operation] That is, in the present invention, as shown in FIG. 1, a pair of cameras 2 and 2 are installed at intervals according to the pitch dimension of the marks 11 and 12 on the planned workpiece 1. Both cameras 2 and 2 capture an image of a reference scale 5 having two reference marks 51 and 52 whose pitch dimension Ls is known. At this time, the images 51a and 52 of the fiducial marks 51 and 52 in the screen visual fields of the cameras 2 and 2, respectively.
If the coordinate position with respect to the predetermined point of a, that is, the screen visual field centers o ₁ and o ₂ is ξ ₁ η ₁ and ξ ₂ η ₂ as shown in FIG. 2, the center o ₁ of the two cameras 2 and 2 is , O ₂ the pitch Lc is Lc = (Ls ² − (η ₂ −η ₁ ) ² ) ^1/2 + ξ ₁ −ξ
It can be calculated by ₂ . Next, as shown in FIG. 3, the marks 11,
When 12 is placed in the screen view of both cameras 2 and 2, the coordinate positions of the images 11a and 12a of both marks 11 and 12 in the screen view are x ₁ y ₁ and x ₂ y as shown in FIG. If it is ₂ , the pitch L _M between marks of the workpiece 1 and the inclination angle α with respect to the center line between cameras are L _M = ((Lc + x ₂ −x ₁ ) ² + _(y 2 _-y ^{1) 2)}
It can be calculated by ^1/2 α = tan ⁻¹ ((y ₂ −y ₁ ) / (Lc + x ₂ −x ₁ )). For this reason, the pitch shift and other marks 11, The relative relationship between 12 can be detected accurately. Further, if the positions of the marks 11 and 12 thus obtained are different from those at the time of designing, the positions of the marks 11 and 12 are deviated. Therefore, based on the value of this error, It is possible to make a correction to shift the drilling position from the positions of the marks 11 and 12. [Embodiment] FIG. 5 shows an example of an apparatus configuration in the case of performing reference hole processing at two positions of a workpiece 1 which is a multilayer wiring board. Two
While one of the two cameras 2 and 2 is arranged in a fixed state, the remaining one camera 2 is attached to the moving device 3 in the same manner as that shown in the above-mentioned conventional example. The pitch between the cameras 2 and 2 can be changed according to the change of the type of the material 1 to be processed. The workpiece 1 is set so that the marks 11 and 12 on the workpiece 1 are located directly under the cameras 2 and 2, respectively.
It is fixed by the pressers 6, 6. Below the position where the workpiece 1 is set, drill units 7, 7 are installed at positions substantially corresponding to the cameras 2, 2. The drill unit 7 is lifted by an elevating unit 8 including a motor and a cam, so that the workpiece 1 is drilled. Further, the drill unit 7 and the lifting unit 8 are mounted on the XY table unit 9 in order to correct the drilling position. Although the lifting unit 8 and the XY table unit 9 are not shown in the drill unit 7 corresponding to the camera 2 on the moving side, the XY table unit 9 for this drill unit 7 has a movement stroke comparable to that of the camera 2. The one that has a unidirectional stroke is used. Reference numeral 20 in the figure denotes a display for displaying an image pickup screen of the camera 2. Then, in this device, the mark 1 of the workpiece 1 is
When making holes at positions 1 and 12, both cameras 2 and 2 are set at intervals substantially corresponding to the pitch between the marks 11 and 12 of the workpiece 1, and in this state, the reference scale is used to As described above, the center-to-center pitch Lc of both cameras 2 and 2 is accurately obtained. After that, the work material 1 to be drilled is set, and the pitch L between the marks 11 and 12 is set.
Measure _M. The pitch error Δx = L _M −Lo between the design target pitch dimension Lo and the measured pitch L _M is
For example, as shown in FIG. 6, processing is performed by actually making a hole on a line connecting the centers of the marks 11 and 12 and at a position deviated from each of the marks 11 and 12 by Δx / 2. The case of the fixed camera 2 will be explained. As shown in FIG. 7, when the image 11a of the mark 11 is at the coordinate x ₁ y ₁ in the screen field of view of the camera 2, the pitch between marks obtained as described above is calculated. and L _M and angle alpha, and a design pitch dimension _{Lo, Δx / 2 = (L} M -Lo) / 2 are those which can be obtained, the coordinates _X 1 _{Y 1} position to be drilled is X ₁ = x ₁ + cos α · Δx / 2 Y ₁ = y ₁ −sin α · Δx / 2, and the drill unit 7 moves to this position and then drills. The pitch of the reference holes formed in this way is determined by the marks 11, 1
The design dimension can be ensured irrespective of the position error of No. 2, and the relative position of the reference hole on the workpiece 1 does not shift to either mark side. As the reference scale, ceramics, glass, or the like that is not easily affected by temperature or the like is used. Further, as a method of calibrating the relative positional relationship between the drill unit and the camera corresponding thereto, a method of taking an image of the tip of the drill with a camera and recognizing its position can be adopted.

【The invention's effect】

As described above, in the present invention, since the states of the plurality of cameras after being installed are measured using the reference scale, the installation accuracy of the cameras does not affect the deviation of the drilling position. Therefore, it is not necessary to improve the accuracy, and it is only necessary to put a mark in the imaging field of the camera for the set of workpieces, and there is no need for accuracy in setting. As long as the scale accuracy is high, it is possible to perform accurate correction at a relatively low cost without requiring advanced technology for designing and manufacturing equipment and handling thereof.

[Brief description of drawings]

FIG. 1 and FIG. 2 are perspective views and a screen field view showing a state at the time of reference scale imaging in the present invention, and FIGS. 3 and 4 are perspective views and a screen field view showing the state at the time of processing a workpiece as above. FIG. 5 is a perspective view showing an example of an apparatus according to the above,
FIGS. 6 and 7 are explanatory views of the same as above, FIG. 8 is a perspective view of an apparatus according to a conventional example, FIG. 9 is a perspective view of another apparatus, and FIG. 10 is an explanatory view showing problems of the same. Yes, 1 is the work material,
2 is a camera, 5 is a reference scale, 11 and 12 are marks,
Reference numerals 51 and 52 denote reference marks.

Claims (1)

[Claims] 1. A predetermined point in each screen field of view of a plurality of cameras installed at intervals substantially corresponding to the intervals of a plurality of marks for indicating a drilling position provided on a work material. The interval is determined by imaging the reference scale with these cameras, and the mark is determined from the position coordinates of the mark of the workpiece imaged by these cameras with respect to the predetermined point in the screen visual field and the interval between the predetermined points. A method for correcting a hole drilling position, which calculates a space between the holes and corrects a drilling position from a deviation between a design dimension between the marks and the calculated space between the marks.