JP3067505B2 - Screen printing equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a screen printing apparatus.

[0002]

2. Description of the Related Art A screen printing apparatus is widely used as an apparatus for applying cream solder for soldering to a circuit pattern formed on a substrate. In addition, in the screen printing apparatus, in order to be able to apply cream solder to a plurality of types of substrates, a plurality of types of screen masks corresponding to the types of the substrates in a one-to-one correspondence are stored in a magazine in multiple stages.
The screen mask corresponding to the type of the substrate carried into the screen printing apparatus is taken out from the magazine to the printing area and printing is performed.

[0003]

Here, since the type of screen mask is controlled by the magazine level, a screen mask of a certain type must be stored in a predetermined level of the magazine. However, when the operator mistakes the stage for storing the screen mask, or when the screen mask is of the correct type but the direction is wrong, the correct operation may not be performed as it is.

In such a case, an identification label such as a bar code label is attached to the frame of the screen mask in order to check the type of the screen mask reaching the printing area, and a reading device such as a bar code reader for reading the label is provided. It is also possible. However, in this case, the cost is inevitably increased, and the identification label is worn when the screen mask is moved, or the cream solder adheres, and the reading error is likely to occur, which is not appropriate.

Accordingly, an object of the present invention is to provide a screen printing apparatus capable of determining whether or not a screen mask reaching a print area is appropriate without changing the screen mask itself.

[0006]

According to the present invention, there is provided a screen printing apparatus comprising: a magazine for accommodating a plurality of types of screen masks in multiple stages; and a mask for inserting and removing a screen mask between a designated stage of the magazine and a printing area. An exchange unit, a camera for observing the screen mask that has reached the printing area, and data of the opening of the screen mask are stored for each type of screen mask, and the data of the opening of the designated type and the image of the camera are stored. A mask recognizing circuit for comparing and discriminating a coincidence or a non-coincidence, and information on a stage in which a screen mask of a type to be taken out to a printing area is to be stored in a mask exchanging section, and data of an opening of this type is supplied to the mask recognizing circuit. And a control unit to be specified.

[0007]

According to the above arrangement, the control section gives step information to the mask exchanging section, and the mask exchanging section takes out the screen mask from the step designated by the step information of the magazine to the printing area. Then, the camera obtains the image of the screen mask and outputs it to the mask recognition circuit. Further, the control unit instructs the mask recognition circuit of the type that should be stored in the above stage. The mask recognition circuit compares the data of the opening of the type specified by the control unit with the image of the camera, and determines whether they match or mismatch. Of course, if the discrimination results match, the screen mask of the print area is interpreted as appropriate, and if they do not match, it is interpreted as inappropriate.
Note that the above comparison is performed by focusing on the opening of the screen mask, and naturally utilizes the fact that the shape, arrangement, etc. of the opening are different if the type of screen mask is different. It is possible to determine the suitability of the screen mask without taking any special measures such as attaching a mask.

[0008]

Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view of a screen printing apparatus according to an embodiment of the present invention. In FIG. 1, reference numeral 1 denotes a base, and 2 denotes a substrate positioned by a substrate positioning unit A provided on the base 1. Among the substrate positioning portions A, 3 is an X table mounted on the base 1 and driven by an X motor 4.
5 is a Y table mounted on the X table 3 and driven by a Y motor 6, 7 and 8 are substrate holders for clamping a side portion of the substrate 2, 9 is provided on the Y table 5, and a lifting means (not shown) The first Z table 10 that moves up and down integrally with the substrate holder 7 and the substrate holder 8 is fixed to a suction block 11 that sucks the lower surface of the substrate 2, and is independent of the first Z table 9 by lifting means (not shown). The second to go up and down
Is a Z table.

Reference numeral 12 denotes a magazine for accommodating a plurality of screen masks 13 in multiple stages for each type, and B denotes a magazine 12
Is a mask exchanging unit for taking the screen mask 13 in and out between the designated area and the printing area S. Of the mask replacement section B, 14 and 15 guide the screen mask 13 slidably in the Y direction on opposite sides, and a mask guide horizontally supported on the base 1 by a support post 16, and 17 is a lift motor. A lifter that drives the screen mask 13 at the designated level of the magazine 12 to the same level as the guide surfaces of the mask guides 14 and 15 by driving the magazines 18 is provided on one of the mask guides 15. The screen mask 13 is engaged with the screen mask 13 at the same level as the guide surface of the mask guide 15 by moving means (not shown).
Is a draw-out claw for taking in and out between the magazine 12 and the print area S.

Reference numeral C denotes a printing unit, of which 20 is a squeegee that slides on the screen mask 13 to apply cream solder to the substrate 2, 21 is a squeegee head that supports the squeegee 20 so as to be able to move up and down, and 22 is a squeegee 20. The lifting cylinder 23 is connected to the squeegee head 21,
A feed nut 25 screwed into a feed screw 24 rotatably supported along the Y direction outside the mask guide 15;
Is a slide motor for rotating the feed screw 24. The squeegee head 21 holds the upper surfaces of the mask guides 14 and 15 in Y
It is slidably mounted along the direction. Accordingly, the substrate positioning unit A is driven to place the substrate 2 in the print area S.
Is moved, the cylinder 22 is driven to bring the lower edge of the squeegee 20 into contact with the upper surface of the screen mask 13, and the slide motor 25 is driven to move the squeegee head 21 and the squeegee 20 in the direction of the arrow N1. The cream solder can be applied to the substrate 2 through the opening. The mask guides 14 and 15 are provided with fixing means (not shown) for fixing the screen mask 13 drawn out to the printing area S, so that the position of the screen mask 13 does not shift during printing.

Reference numeral 26 denotes a camera (hereinafter, referred to as a mask camera) for observing the screen mask 13 reaching the print area S and capturing an image of the screen mask 13, and 27 denotes a camera (hereinafter, referred to as a camera) for capturing an image of the substrate 2 loaded. Board camera).

FIG. 2 is a block diagram of a screen printing apparatus according to one embodiment of the present invention, and FIG. 3 is a block diagram of a mask recognition circuit of the screen printing apparatus according to one embodiment of the present invention. In FIG. 2, reference numeral 28 denotes a ROM (Read Only Memory) storing a control program according to the flowchart of FIG. 5, 29 executes a control program of the ROM 28,
A CPU (Central Processing Unit) 30 as a control unit for controlling each element in FIG. 2 is for executing step information indicating which type of screen mask 13 is stored in which level of the magazine 12 and the above control program. (Random access memory) provided with an area for storing data necessary for the operation, and 31 is a CR for displaying an operation state or the like to an operator.
T (cathode ray tube) and 32 are keyboards for the operator to input necessary information such as operation commands.

Numeral 40 stores the data of the opening of the screen mask 13 for each type of the screen mask 13 and compares the data of the opening of the specified type with the image of the mask camera 26 to determine whether they match or mismatch. This is a mask recognition circuit to perform. As shown in FIG. 3, the mask recognizing circuit 40 digitizes the image of the mask camera 26.
A / D converter 41, an image memory 42 for storing digitized images, a reference pattern memory 43 for storing a reference pattern including the shape and position of the opening for each type of screen mask 13, an image and a reference for the image memory 42 The pattern memory 43 includes a pattern matching circuit 44 that performs pattern matching with a designated reference pattern and outputs a matching ratio and position information of the opening. This position information is used when the substrate 2 and the screen mask 13 are aligned by the substrate positioning unit A. In the present embodiment, the above-described reference pattern corresponds to the data of the opening of the screen mask 13. In FIG. 2, reference numeral 50 denotes a board camera 2.
7, a board recognition circuit for recognizing the type of the board 2 carried in from the image 7, a positioning section drive circuit 51 for driving the board positioning section A, a printing section drive circuit 52 for driving the printing section C,
An exchange unit driving circuit 53 drives the mask exchange unit B.

FIGS. 4A to 4D are illustrations of reference patterns of a screen printing apparatus according to an embodiment of the present invention, wherein hatched portions indicate openings. FIG. 4A shows the reference pattern of the type A, and FIG. 4B similarly shows the type B and FIG.
FIG. 4D shows a reference pattern of the product type C, and FIG.
As shown in FIGS. 4A to 4D, the screen mask 13
Are different in shape, arrangement, number and the like of the openings. This is because if the type of the substrate 2 is different, the circuit pattern is different, and the shape of the region (opening) to which the cream solder is to be applied is different. Therefore, the type of the screen mask 13 can be determined based on the opening without taking any special measures such as attaching an identification label to the screen mask 13.

FIG. 5 is a flowchart showing a mask replacement step of the screen printing apparatus according to one embodiment of the present invention. Next, the operation of the screen printing apparatus according to one embodiment of the present invention will be described with reference to the flowchart of FIG. I do.

First, prior to the printing process by the screen printing apparatus, the user operates the keyboard 32 to store the type information of the substrate 2 on which the cream solder is to be printed this time.
0 is registered. Then, when the user inputs a command to start the printing process using the keyboard 32, the screen printing device first executes the mask replacement process shown in the flowchart of FIG. That is, in FIG.
The type information of the substrate 2 on which the cream solder is to be printed this time, which is stored in M30, is read (step 1). Next, the CPU 29 passes through the exchange unit drive circuit 53,
The step information in the magazine 12 in which the screen mask 13 of the type read in step 1 is to be stored is given to the mask replacing section B, and the screen mask 13 stored in the step is drawn out to the print area S, and the print area It is fixed to S (step 2). Of course, if the used screen mask 13 remains in the printing area S, the screen mask 13 is stored in the magazine 12 first. Next, the CPU 29 causes the mask camera 26 to observe a predetermined position of the screen mask 13 drawn into the print area S. Thus, the image of the mask camera 26 is digitized by the A / D converter 41 in the mask recognition circuit 40 and then stored in the image memory 42 (step 3). Further, the CPU 29 gives the type information read in step 1 to the mask recognition circuit 40 and instructs the reference pattern of this type to be compared with the image stored in the image memory 42 in step 3. That is, the CPU 29 specifies the reference pattern to be collated by giving the type information to the mask recognition circuit 40. As a result, the pattern matching circuit 44 stores the reference pattern and the image memory 42
Pattern matching with the middle image is performed, and the obtained matching ratio and position information of the opening are returned to the CPU 29 (step 4).

Here, the CPU 29 compares the matching ratio obtained from the pattern matching circuit 44 with a preset threshold value (step 5). It interprets that the screen mask 13 has been drawn to the print area S, calculates the position information of the screen mask 13 drawn with reference to, for example, the position of the center of gravity of the opening, and writes it in a predetermined area of the RAM 30 (step 6). When the mask replacement step is completed, cream solder is printed on the substrate 2 positioned at the substrate positioning section A. On the other hand, if the matching rate is lower than the threshold value, an error message is displayed on the CRT 31 to call attention of the operator, and the drawn-out screen mask 13 is returned to the original stage (step 7). Accordingly, it is possible to check for an error in the type of the screen mask 13, an error in the direction in which the screen mask 13 is stored, a large positional shift, and the like before performing the printing process by the printing unit C.

As described above, the screen printing apparatus of the present embodiment uses pattern matching to determine whether the shape of the opening of the screen mask 13 matches the shape of the opening of the desired type of screen mask 13. Although the examination has been made, it may be changed so that the collation is performed using the center of gravity and area of the opening, and information on the characteristic points of the contour shape of the opening.

[0019]

According to the present invention, there is provided a screen printing apparatus comprising: a magazine for storing a plurality of types of screen masks in multiple stages;
A mask exchange unit that moves the screen mask in and out of the designated area of the magazine and the printing area, a camera that observes the screen mask that has reached the printing area, and data on the opening of the screen mask for each type of screen mask In addition to storing the data, the data of the opening of the specified type is compared with the image of the camera, and a mask recognizing circuit for judging coincidence or non-coincidence is stored in the mask exchanging section. Since a control unit for giving power level information and designating data of the opening of this type in the mask recognition circuit is provided, it is possible to automatically determine the suitability of the screen mask without taking special measures for the screen mask. .

[Brief description of the drawings]

FIG. 1 is a perspective view of a screen printing apparatus according to an embodiment of the present invention.

FIG. 2 is a block diagram of a screen printing apparatus according to an embodiment of the present invention.

FIG. 3 is a block diagram of a mask recognition circuit of the screen printing apparatus according to one embodiment of the present invention.

4A is a view showing an example of a reference pattern of a screen printing apparatus according to an embodiment of the present invention. FIG. 4B is a view showing an example of a reference pattern of a screen printing apparatus according to an embodiment of the present invention. FIG. 4D is a view showing an example of a reference pattern of a screen printing apparatus according to an embodiment of the present invention.

FIG. 5 is a flowchart showing a mask replacement process of the screen printing apparatus according to one embodiment of the present invention.

[Explanation of symbols]

 12 Magazine 13 Screen Mask 26 Mask Camera 29 CPU B Mask Replacement S Printing Area

Continuation of the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B41F 15/08 B41F 15/36 H05K 3/12 H05K 3/34

Claims (1)

(57) [Claims] 1. A screen printing apparatus for sliding a squeegee on a screen mask and applying cream solder to a substrate through an opening of the screen mask, comprising: a magazine for accommodating a plurality of types of screen masks in multiple stages; A mask exchange unit that takes the screen mask in and out between the designated step and the printing area, a camera that observes the screen mask that has reached the printing area, and data on the opening of the screen mask for each type of screen mask In addition, a mask recognition circuit for comparing the data of the opening of the specified type with the image of the camera to determine a match or mismatch, and a screen mask of the type to be taken out to the print area are stored in the mask exchange unit. Give the information of the stage to be
A screen printing apparatus, comprising: a control unit for designating data of an opening of this type in the mask recognition circuit.