JPH0476239B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a printing mask alignment method for aligning a mask for printing paste solder to a printed board.

[Background of the invention]

With reference to FIG. 9, a method of printing paste solder on a printed circuit board for mounting and connecting flat pack type parts will be explained. Reference numeral 103 designates a printing mask, in which a metal mask 104 made of a thin metal plate is held under tension by a mesh 107 and attached to the fixed frame 10.
It is attached to 6. This printing mask 1
03 on the printed board 101, and apply paste solder 109 to the metal mask 10 using a flat squeegee 108 made of a flexible material such as urethane.
4 in the direction of the arrow 110, the paste supply hole 10 of the metal mask 104 is opened.
Paste solder 109 from 5 to printed board 10
1 page is supplied and the component connection portion 102 is printed.

Now, conventionally, as shown in FIG. 10, from above the metal mask 104, as shown by the arrow 112, the component connecting portion 102 is fed through the paste supply hole 105.
The printing mask 103 and the printed board 101 are aligned by moving the printing mask 103 using a means such as a micrometer while visually checking the position. However, in such a method, the positional deviation Δ is quite large, and as the mounting density of the printed circuit board 101 increases and the component connecting portion 102 becomes finer, the positional deviation cannot be ignored.
Furthermore, since it relies on direct visual inspection, workability is poor and the time required for alignment is long.

In addition, Japanese Patent Application Laid-Open No. 58-89893 discloses a method of aligning a printing mask and a printed board by inserting a probe into a reference hole in a metal mask and detecting electrical connection with a reference pattern on a printed board. has been disclosed. However, this method also cannot improve the alignment accuracy much.

[Purpose of the invention]

An object of the present invention is to provide a printing mask alignment method that can efficiently and highly accurately align a paste solder printing mask to a printed board.

[Summary of the invention]

In order to realize the printing mask alignment of the present invention, a mask includes a mechanism for holding a printing mask made of paste solder, and a driving device that operates the mechanism to move the printing mask held by the mechanism. a holding device, a control device for controlling the drive device, an imaging device for capturing images of positioning marks on a fixed printed board and position detection marks on a printing mask held by the mask holding device;
and a monitor device that displays an image captured by the imaging device on a screen. The monitor device has a function of moving a cursor on the screen to an arbitrary position.

The alignment of the printing mask is performed in the following steps. First, the operator causes the imaging device to take an image of the positioning mark on the fixed printed board, and displays the image on the screen of the monitor device. The operator places the cursor on the fundamental image point of the image. Next, a printing mask is set on the mask holding device, and the position detection mark of the printing mask is imaged by the imaging device and displayed on the screen of the monitor device. Then, by controlling the drive device via the control device, the operator adjusts the printing mask and the image so that the reference point of the position detection mark displayed on the screen of the monitor device matches the position of the cursor. The printing mask is aligned with the printed board by adjusting its relative position with the printed board.

[Embodiments of the invention]

Hereinafter, one embodiment of the present invention will be described with reference to FIGS. 1 to 8.

First, with reference to FIG. 2, the overall configuration of a paste printing machine that achieves the printing mask alignment method of the present invention will be explained. In this figure, 18 is a table on which the printed board 1 is set. 3 is a printing mask, and after being aligned with the printed board 1 at the position of the solid line by the printing mask alignment device, it is lowered as shown by the broken line 3',
It becomes possible to print paste-like solder. 25 is a squeegee head to which the squeegee 8 is attached. This squeegee head 25 is slidably supported by a support rack 51 and is screwed into a ball screw 27. By rotating the ball screw 27 by a drive device 28 consisting of a motor or the like, the squeegee head 25 is slid from side to side in the figure. Reference numeral 26 denotes a lifting device consisting of a hydraulic cylinder, a gear cylinder, etc., and the squeegee head 25 is raised and lowered together with the support frame 51 by this lifting device 26.

When printing paste solder, the printing mask 3 is aligned and lowered, and then the paste solder is supplied onto the printing mask 3. Then, the squeegee head 25 is lowered and moved from the left end in the figure to the right. As a result, paste solder is supplied to the surface of the printed board 1 via the printing mask 3, and a predetermined conductor pattern is printed.

The printing mechanism itself is the same as before, so
Without further explanation, a positional configuration for achieving the positioning method of the present invention will be described.

In FIG. 1, 14 is a mask holding device, and the printing mask 3 held there is
It is provided with means for moving in a direction (described later). Its movement can be controlled by the operator through the control device 17. The mask holding device 14 includes a mask insertion guide rail 20 and a mask receiver 19.
A pair of each is provided. Reference numeral 15 designates imaging devices such as television cameras, which are provided at three locations facing vertically downward. Since the installation position and number of the imaging devices 15 affect the positioning accuracy and operability, it is generally preferable to set the number of the imaging devices 15 to two or more and four or less on the outer circumference of the printed board 1. Reference numeral 16 denotes a monitor device, which includes a screen 52 corresponding to each imaging device 15. After being imaged by each imaging device 15,
It is displayed on the corresponding screen 52 at a constant magnification. Further, the monitor device 16 displays a cross-shaped cursor 44 on each screen 52, and the operator can move the cross-shaped cursor 44 on each line in the X, Y, and direction as desired. Since such a monitoring device 16 itself is common, its details will not be explained.

Note that the table 18 on which the printed board 1 is set is
The apparatus is equipped with a means using a vacuum pump or the like for correcting the warpage of the printed board 1, and a mechanism that can move up and down to correct variations in the thickness of the printed board 1. Furthermore, after setting the printed circuit board 1, the table 18 is moved in the direction of the arrow 22 and stopped at the printing position, and after printing is completed, the table 18 is moved in the opposite direction in order to remove and reset the printed circuit board. exists, but is omitted in the figure. This mechanism is also controlled by the control device 17. Furthermore, cross-shaped patterns 42 are formed at the four corners of the printed board 1 as positioning marks.

Details of the mask holding device 14 will be explained with reference to FIGS. 3 to 5. Mask holding device 14
As a mechanism for movably holding the printing mask 3, a θ table 34 that can rotate in the θ direction about a fulcrum 31, an X table 32 that can move in the X direction with respect to the θ table 34, and table 32
The device movable in the Y direction is provided with a combination mechanism consisting of a Y table 30, a pair of mask insertion guide rails 20, and a pair of mask receivers 19. Moreover, each of such tables 30, 32,
34 respectively, the control device 17
Y-direction drive device 37, X-direction drive device 38, which consists of a motor, hydraulic cylinder, etc. controlled by
A directional drive device 39 is provided. The Y-direction drive device 37 and the X-direction drive device 38 are attached to the θ table 34, but the θ-direction drive device 39 is attached to a fixed member (not shown). Note that each of the tables 30, 32, and 34 is made of a relatively lightweight material such as aluminum.

As mentioned above, the mask holding device 14 is provided with a pair of mask insertion guide rails 20 and a pair of mask receivers 19 (see FIG. 3), which will be explained with reference to FIG. 5. As shown in the figure, the Y table 30 is provided with a drive device 46 such as a hydraulic cylinder. This drive device 46 is also controlled by the control device 17. Although the drive devices 46 are provided at the four corners of the Y table 30, only one drive device is shown in the figure. Each mask insertion guide rail 20 includes a member 5 that is moved vertically relative to the Y table 30 by a pair of drive devices 46.
3 (pair). Further, each mask holder 19 is attached to a pair of slide shafts 54 (there are four in total) each supported by the Y table 30 so as to be slidable up and down. Each slide axis 5
A stopper 47 is fixed to the mask receiver 19, and when the weight of the printing mask 3 is applied to the mask receiver 19,
The mask receiver 19 is lowered to a position where the stopper 47 engages with the lowering position adjustment screw 55. If the weight of the printing mask 3 is not applied to the mask receiver 19,
The position where the stopper 47 engages with the upward position adjustment screw 57 due to the action of the spring 56 (broken line 19')
rises to.

Further, as shown in FIG. 3, the mask receiver 19
A pin 21 for rough positioning is provided protruding from the.

As shown in FIG. 6, the printing mask 3 is constructed by attaching a metal mask 4 made of a thin metal plate to a fixed frame 6 made of aluminum or the like with tension through a mesh 7 made of stainless steel or the like. In addition to the paste supply hole 5, a cross-shaped hole 36 as a position detection mark is formed in the metal mask 4 at a position corresponding to the cross-shaped pattern 42 of the printed board 1 by etching. Holes 40 and 41 are formed in the fixed frame 6 at positions corresponding to the rough positioning pins 21 of the mask receiver 19. One hole 40
is a circular hole for rough positioning in the XY direction, and the other hole 41 is an elliptical hole for coarse positioning in the θ direction.

Next, the alignment operation will be explained with reference to FIGS. 7 and 8.

First, the operator places printed board 1 on table 1.
8 and instructs the control device 17 to move the table. Then, the control device 17
8, move the table 18 in the direction of arrow 2.
2, and the printed board 1 is placed in the printing device directly below the mask holding device 14 (the position shown in FIG. 2).
to stop. Each imaging device 15 images the corresponding cross-shaped pattern 42 on the printed board 1,
The image 42' is the corresponding screen 52 of the monitor device 16.
will be displayed. The operator has a monitor device 16
By operating the operating section, the cursor 44 is moved and the intersection of the XY lines of the cursor 44 is aligned with the intersection (reference point) of the image 42' (FIG. 7). The position of cursor 44 is fixed there during the alignment period.

Next, the operator inserts the printing mask 3 along the mask insertion guide rail 20 and sets it on the mask holding device 14. At this time, the mask insertion guide rail 20 is raised, and the printing mask 3 is held at the position indicated by the broken line 3' in FIG. 5.
Thereafter, the operator instructs the control position 17 to lower the mask insertion guide rail 20. Then, the control device 17 operates the drive device 46,
The mask insertion guide rail 20 is lowered to the lowered position. As a result, the set printing mask 3
The weight of the mask holder 19 is increased, and the mask holder 1
9 descends together with the printing mask 3 to the position shown by the solid line in FIG. 5 and comes to rest. At this time, the printing mask 3 is roughly aligned by inserting the coarse positioning pins 21 into the holes 40 and 41, and each cross-shaped hole 36 falls within the field of view of the corresponding imaging device 15. Cross-shaped hole 3 imaged by imaging device 15
The image 36' of No. 6 is displayed on the screen of the monitor device 16 as shown in FIG. The operator operates the control device 17 while observing the image 36' and the cursor 44 displayed on the screen to remove the printing mask 3 set in the mask holding device 14.
is slightly moved in the X, Y, and θ directions, and the intersection point (reference point) of the image 36' is made to coincide with the intersection point (reference point) of the cursor 44. The alignment is now complete.

Printing is performed when alignment is completed. Since this printing is as described above, its explanation will be omitted here.

When printing is finished, the operator presses the control device 17.
By operating , the mask insertion guide rail 20 is raised. As a result, the printing mask 3 also rises, and the mask receiver 19 is moved up by the broken line 1 in FIG.
It will rise to the 9' position. After that, the operator operates the control device 17 to control the table 1.
8 in the opposite direction of the arrow 22 (FIG. 2), the printed printed board 1 is removed from the table 18, and a new printed board to be printed next is set.

In the above embodiment, the shape, position, and number of the cross-shaped hole 36 as the position detection mark and the cross-shaped pattern 42 as the positioning mark can be changed. In the above embodiment, the intersection of the cursor 44 and the intersection (center) of the images 36' and 42' are set as reference points, but the reference points may be changed. However, in order to improve the alignment accuracy,
It is generally advantageous to choose the center of the images 36', 42' as the reference point. The shape of the cursor 44 can also be changed. Further, the configuration of the mask holding device 14 can be changed as appropriate. Furthermore, the configuration of the printing mask 3 is not limited to the above.

〔Effect of the invention〕

In the printing mask positioning method of the present invention, first, a printed board is fixed, a positioning mark on the printed board is imaged by an imaging device, the image is displayed on the screen of a monitor device, and the displayed positioning mark is Place the cursor on the image of the mark, use the cursor position as a positioning reference, set the printing mask, take an image of the position detection mark on the printing mask with the same imaging device, and transfer the image to the same monitoring device. Since this method moves and positions the printing mask so that the image of the displayed position detection mark matches the cursor position, the following effects can be achieved.

(1) Compared to direct visual alignment,
The alignment accuracy can be greatly improved,
Furthermore, positioning can be performed efficiently and in a short time.

(2) Work safety can be improved because the worker's hands can be prevented from touching the printing mask to which paste solder adheres during alignment work.

(3) The positioning mark on the printed board and the position detection mark on the printing mask should be
Shape etc. can be set independently.

(4) The positioning mark provided on the printed board, which serves as a positioning reference, does not need to be a through hole, and the imaging device can be installed, for example, above the printing table, so that structural complexity can be avoided.

[Brief explanation of the drawing]

FIG. 1 is an exploded perspective view of a printing mask positioning device according to an embodiment of the present invention, and FIG. 2 is a schematic front view with some parts omitted showing the overall configuration of a paste printing machine according to an embodiment of the present invention. FIG. 3 is a partially omitted plan view of a mask holding device according to an embodiment of the present invention, FIG. 4 is a partially cutaway schematic side view of the same mask holding device, and FIG. 5 is a partially cutaway side view of the same mask holding device. 6 is a plan view showing a printing mask according to an embodiment of the present invention; FIG. 7 is an explanatory diagram of the operation of placing a cursor on an image of a positioning mark on a printed board; FIG. 8 is an explanatory diagram of the operation of aligning the image of the position detection mark of the printing mask with the cursor, and FIG. 9 is a perspective view for explaining the method of printing paste solder on a printed board using the printing mask. FIG. 10 is a cross-sectional view for explaining a conventional method of aligning a printing mask and a printed board. 1... Printed board, 3... Printing mask, 14
...Mask holding device, 15...Imaging device, 16...
... Monitor device, 17 ... Control device, 18 ... Table, 19 ... Mask holder, 20 ... Mask insertion guide rail, 21 ... Rough positioning pin,
30...Y table, 32...X table, 34
...θ table, 36...Cross-shaped hole as position detection mark, 37...Y direction drive device, 38...
X-direction drive device, 39...θ-direction drive device, 4
0, 41... Rough positioning hole, 43... Cross-shaped pattern as a positioning mark, 44... Cursor, 46... Drive device.

Claims (1)

[Scope of Claims] 1. A mask holding device comprising a mechanism for movably holding a pasty solder printing mask and a drive device that operates the mechanism to move the printing mask held by the mechanism; A control device for controlling the drive device, an imaging device, and a monitor device for displaying an image taken by the imaging device, first, a printed board is fixed, and positioning marks provided on the printed board are provided. is imaged by the imaging device, the image is displayed on the screen of the monitor device, the cursor is placed on the displayed positioning mark image of the printed board, and then a printing mask is placed on the mask holding device. The position detection mark provided on the printing mask is imaged by the imaging device, the image is displayed on the screen of the monitor device, and the displayed position detection mark image of the printing mask is at the position of the cursor. A method for aligning printing masks, characterized in that the control device controls the driving device to move the printing masks so that they match.