JPH0848026A - Printing control method for screen printing and screen printing apparatus - Google Patents

Abstract

PURPOSE:To control screen printing so as to form a highly accurate resistor for a sensor uniform in the thickness of a printing layer and reduced in the irregularity of the resistance value thereof. CONSTITUTION:A squeegee strain detection part 28 for detecting the strain quantity of a squeegee 27 when the squeegee 27 moves on a screen mask 29 while applies printing pressure is provided to the squeegee 27 and a control part 36 for controlling the squeegee 27 at the time of screen printing on the basis of the strain quantity detected by the squeegee strain detection part 28 is provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a print control method at the time of screen printing and a screen printing apparatus using the same, and more specifically, in forming a highly accurate resistor for a sensor or the like, The present invention relates to a screen printing control method and a screen printing device capable of controlling the thickness of a printed layer of a resistor with high accuracy.

[0002]

2. Description of the Related Art In recent years, in screen printing technology, there is an increasing demand for downsizing of electronic devices and miniaturization of electronic circuits and higher precision of electronic circuits, and thus there has been a demand for highly accurate resistor printing for sensors. There is.

The formation of the resistor for this sensor is usually
A screen printing technique is used. As shown in FIG.
A rectangular parallelepiped squeegee 4 made of a rubber material is supported by a squeegee holder 3 and has an appropriate angle θ (squeegee angle θ).
And is attached to the pressure drive unit 2. Further, the screen mask 5 has a plurality of ring-shaped transfer patterns formed on the entire surface thereof and is provided above the material 6 to be printed with a gap A therebetween. Then, the squeegee 4 is pushed downward by the pressure drive unit 2, the squeegee 4 is pressed against the screen mask 5 and horizontally moved by the squeegee drive unit 1 while applying a printing pressure to the screen mask 5, and the squeegee 4 is supplied onto the screen mask 5. A paste 8 made of a carbon resistor material or a Ru-based cermet resistor material is spread by pressure, and the printed material 6 is placed on and supported by the stage 7.
A plurality of ring-shaped resistors are formed by printing, and one printing is completed.

As described above, when the paste 8 supplied onto the screen mask 5 is pressed and spread by the squeegee 4 to form the resistor by printing, the substrate 6 and the screen mask 5 are printed.
The gap A between the squeegee, the printing pressure by the squeegee 4, its moving speed, and the degree of its squeegee angle are extremely important factors in determining the thickness of the printed layer of the resistor. That is, when the printing pressure by the squeegee 4, its moving speed, and its squeegee angle are constant, the printing layer becomes thin when the gap A between the printing object 6 and the screen mask 5 is large, and the printing layer becomes thin when the gap A is small. Get thicker. Further, when the gap A between the printing object 6 and the screen mask 5, the moving speed of the squeegee 4 and the squeegee angle thereof are constant, the printing layer becomes thin when the printing pressure by the squeegee 4 is large, and the printing is made when the printing pressure is small. The layers get thicker. Further, when the gap A between the printing object 6 and the screen mask 5, the printing pressure by the squeegee 4 and the squeegee angle thereof are constant, the printing layer becomes thicker when the moving speed of the squeegee 4 is increased, and the printing is performed when the moving speed is slowed. The layers get thinner. When the squeegee 4 has a constant gap A and the squeegee 4 and the printing pressure and its moving speed are constant, the squeegee 4 has a large squeegee angle and the printing layer has a small thickness. The printed layer becomes thicker. Until now, after setting the squeegee angle of the squeegee 4 to an appropriate angle, the gap A between the substrate 6 and the screen mask 5 and the squeegee 4 are set.
The thickness of the printing layer was controlled by adjusting the printing pressure and the moving speed in combination.

[0005]

However, in forming a resistor for a high-accuracy sensor which requires high-accuracy resistance control, the squeegee 4 made of a rubber material has elasticity. As shown, distortion occurs in the process of horizontal movement, and the shape of the squeegee 4 changes from a rectangular parallelepiped shape as shown in FIG. 5A to a bow shape protruding in the movement direction as shown in FIG. 5B. It was found that the squeegee angle slightly changes at the tip of the squeegee 4 and the thickness of the printed layer of the resistor to be formed becomes uneven. In general, it is known that the resistance value of a resistor becomes smaller as its thickness becomes thicker and becomes larger as its thickness becomes thinner, assuming that the length and width are constant. As a result, the characteristics of the resistance value vary.

The present invention has been made in view of the above circumstances, and an object thereof is to form a resistor for a sensor with high accuracy in which the thickness of the printed layer is more uniform and the variation of the resistance value characteristic is smaller than in the prior art. It is possible to provide a print control method and a screen printing apparatus capable of performing screen printing.

[0007]

A structural feature of a screen printing printing control method and a screen printing apparatus according to the present invention is that the squeegee moves when the squeegee moves on the screen mask while applying a printing pressure. A means capable of detecting the amount of distortion is provided around the squeegee including the squeegee, and a control controller for controlling the squeegee during screen printing is provided based on the amount of distortion detected by the means.

[0008]

Therefore, the squeegee spreads the paste supplied onto the screen mask while applying printing pressure,
The amount of strain generated in the squeegee can be detected in the process of the squeegee moving on the screen mask while forming a resistor on the printing object by printing, and the squeegee can be detected based on the detected value when the resistor is printed. The thickness of the printed layer of the resistor can be made uniform as compared with the related art by controlling the temperature control, and a resistor with less variation in the characteristics of its resistance value can be obtained.

[0009]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic side view of a main part of a screen printing apparatus according to an embodiment of the present invention.

In FIG. 1, an object to be printed 30 is removably placed on a stage 31 of a screen printing apparatus. A screen mask 29 is provided above the stage 31 with a gap A in between to cover the material 30 to be printed. And although not shown here,
A plurality of horseshoe-shaped transfer patterns for forming horseshoe-shaped resistors are formed at substantially equal intervals on the entire surface of the screen mask 29 that faces the material to be printed 30.
The paste 37 is made of a carbon resistor material, a Ru-based cermet resistor material, or the like, and is applied on the screen mask 29 and supplied. Also, stage 31
A stage drive unit 32 is integrally provided below the.

The gap adjusting unit 33 is the stage driving unit 3
A servo motor (not shown) is provided in the lower part of 2, and is connected to the stage drive unit 32 by a rod-shaped screw shaft 34 that interlocks with the servo motor. Then, the servo motor rotates the screw shaft 34, whereby the stage drive unit 32
Is moved up and down, and the stage 31 provided integrally with the stage drive unit 32 is moved up and down.

A rectangular parallelepiped squeegee 27 made of a rubber material.
Is supported by the squeegee holder 26 and is positioned above the screen mask 29 with a squeegee angle θ as in the conventional case.

The squeegee 27 is shown in FIG.
The squeegee distortion detector 28 of any one of (c) to (c) is provided. The squeegee strain detector 28 shown in FIG. 2A is a strain sensor such as a strain gauge, and is attached to the side wall of the squeegee 27 with an adhesive or the like, and the strain of the squeegee 27 is expanded and contracted by following the strain of the squeegee 27. Is detected and an output corresponding to the magnitude of the distortion is generated, and the squeegee distortion detector 28 shown in FIG.
The pressure sensor is mounted on the side wall of the squeegee holder 26 by screwing or the like, and detects and outputs the magnitude of strain of the squeegee 27. Further, the squeegee strain detecting portion 28 shown in FIG. 2C is a non-contact type sensor such as a laser, which is attached to the side wall of the squeegee holder 26 by screwing or the like and constantly measures the distance from the squeegee 27. The strain of the squeegee 27 is detected and output.

The printing pressure adjusting portion 25 is provided so as to extend downwardly thereof and is vertically moved up and down.
A servo motor (not shown) for moving the shaft 39 up and down, and a printing pressure sensor 41 for detecting and outputting the printing pressure applied to the screen mask 29 by the squeegee 27. positioned.

A squeegee angle adjusting portion 38 is attached to the lower end of the shaft 39 while being supported by a rotating pin 40 so that the squeegee angle adjusting portion 38 can rotate together with the rotating pin 40 like a pendulum. Then, a servo motor (not shown) fixed to the shaft 39 is rotated by a rotation pin 40 via a speed reduction mechanism (not shown) provided in the squeegee angle adjusting section 38.
The squeegee angle adjusting unit 38 can be rotated by driving the squeegee 27. The squeegee 27 supported by the squeegee holder 26 by this rotation is attached to the squeegee angle adjusting unit 38. The angle can be adjusted appropriately.

A pressure drive unit 23 is located above the printing pressure adjustment unit 25, and a servo motor (not shown) is provided inside the pressure drive unit 23. The screw shaft 24 is connected to the printing pressure adjusting unit 25. The servo motor rotates the screw shaft 24 to move the printing pressure adjusting unit 25 up and down.

Further, a squeegee speed adjusting unit 21 is located on the side of the printing pressure adjusting unit 25, and a servo motor (not shown) is provided inside the squeegee speed adjusting unit 21. The screw shaft 22 is connected to the printing pressure adjusting unit 25. The servo motor rotates the screw shaft 22 to move the printing pressure adjusting unit 2
5 is moved horizontally, and the squeegee 27 moves the screen mask 2
It is possible to move above 9.

The control control unit 36 is a pressure drive unit 2.
3, the printing pressure adjusting unit 25, the squeegee speed adjusting unit 21, and the squeegee angle adjusting unit 38 are electrically connected, and the outputs from the squeegee strain detecting unit 28 and the printing pressure sensor 41 are detected, and the squeegee strain detecting unit detects the strain. The change in the output value from the portion 28 can be grasped as the change in the squeegee angle of the tip portion of the squeegee 27. In addition, the printed material 3
The thickness of the printed layer of the resistor formed on the
It has been conventionally obtained that it depends on the gap A between 0 and the screen mask 29, the moving speed of the squeegee 27, the printing pressure by the squeegee 27, and the squeegee angle of the squeegee 27. The control control unit 36 stores these relationships as control data, and combines the control data so that the output value from the squeegee strain detection unit 28 is constant, and the press drive unit 23, the printing pressure adjustment unit 25, By controlling the operations of the squeegee speed adjusting unit 21 and the squeegee angle adjusting unit 38,
The printed layer of the resistor is formed to have a desired thickness.

The manual input unit 35 is electrically connected to the control control unit 36, and registers, changes, adds and deletes control data stored in the control control unit 36, and combines control data of the control control unit 36. You can change who you are.

The operation of the screen printing apparatus configured as described above will be described below with reference to FIG.

First, the material to be printed 30 is placed on the stage 31 of the screen printing apparatus. Next, the paste 37 is applied on the screen mask 29 and supplied. Then, the gap adjusting unit 33 receives the control signal from the control control unit 36 and rotates the screw shaft 34 to raise the stage 31 and position so that the gap A between the screen mask 29 and the printing medium 30 is in an optimum state. To do.

Next, the squeegee angle adjusting section 38 receives a control signal from the control control section 36 and rotates itself,
The squeegee 27 stops when the squeegee angle reaches a desired angle.

Next, the pressurizing drive unit 23 receives the control signal from the control control unit 36 and the screw shaft 24.
By rotating the printing pressure adjusting unit 25,
The squeegee 27 is brought into contact with one end of the screen mask 29. Then, the printing pressure adjusting unit 25 receives the control signal from the control control unit 36, lowers the shaft 39, presses the squeegee 27 against the screen mask 29 to apply the printing pressure to the screen mask 29, and the printing pressure by the squeegee 27 is applied. The printing pressure sensor 41 provided in the printing pressure adjusting unit 25 detects and outputs. The control control unit 36 controls the operation of the printing pressure adjusting unit 25 while receiving the output from the printing pressure sensor 41, and when the desired printing pressure is obtained, the descent of the shaft 39 by the printing pressure adjusting unit 25 is stopped to stop the squeegee 27. Is placed on the screen mask 29.

Thereafter, the squeegee speed adjusting unit 21 receives the control signal from the control control unit 36, rotates the screw shaft 22 and horizontally moves the printing pressure adjusting unit 25, thereby connecting to the printing pressure adjusting unit 25. The squeegee 27 thus pressed is horizontally moved at a desired speed from one end to the other end of the screen mask 29 while being pressed against the screen mask 29. At this time, the squeegee 27 pressurizes and spreads the paste 37 supplied on the screen mask 29.

This squeegee 27 is a screen mask 29.
In the process of moving horizontally from one end to the other end, the squeegee distortion detector 28 continuously detects and outputs the distortion of the squeegee 27. The control control unit 36 regards the output value as a change in the squeegee angle of the squeegee 27, and re-combines the control data so that the output value from the squeegee distortion detection unit 28 becomes constant, and the pressure drive unit 23, The operations of the printing pressure adjusting unit 25, the squeegee speed adjusting unit 21, and the squeegee angle adjusting unit 38 are controlled.

Then, in response to the control signal from the control control section 36, the press adjusting section 25 moves the shaft 39 up and down to increase or decrease the printing pressure applied to the screen mask 29 by the squeegee 27, and the squeegee angle adjusting section 38. Rotate itself and adjust the squeegee angle of the squeegee 27 to an appropriate angle. Similarly, the squeegee speed adjusting unit 21 increases or decreases the rotation speed of the screw shaft 22 to increase or decrease the horizontal movement speed of the squeegee 27. As a result, printing layers of a plurality of resistors are formed on the surface of the material to be printed 30 with a desired thickness, and one printing is completed. After the printing is completed, the pressure driving unit 23, the printing pressure adjusting unit 25, the squeegee speed adjusting unit 21, the squeegee angle adjusting unit 38, and the gap adjusting unit 3
3 returns to the original state.

FIG. 3 shows the resistances at the beginning of printing, the middle point, and the end of printing in one printing by the screen printing apparatus seen in the above-mentioned embodiment and the conventional example.
Measure the resistance value, and set the target resistance value to the reference value 0,
6 is a graph showing a ratio of variation of measured values to that. Graph X is based on the screen printing apparatus shown in the embodiment. The graphs Y and Z are obtained by the screen printing apparatus shown in the conventional example, and the graph Y shows the squeegee angle of the squeegee 4, the object to be printed 6 and the screen mask 5.
The gap A between the squeegee 4 and the squeegee 4 is kept constant and the printing pressure by the squeegee 4 is reduced, and the moving speed of the squeegee 4 is increased. Further, the graph Z shows that the squeegee angle of the squeegee 4 and the gap A between the print object 6 and the screen mask 5 are constant, and the printing pressure by the squeegee 4 is increased, and
It is a slower movement speed. It can be seen that variations in resistance value characteristics of the resistors formed in the examples are suppressed to be extremely small as compared with the conventional example.

Therefore, in the process of horizontally moving the squeegee 27 and printing and forming the resistor, by adjusting the printing pressure by the squeegee 27 and the moving speed and the squeegee angle of the squeegee 27, the distortion amount of the squeegee 27 is kept constant. It is possible to form a resistor having a resistance value characteristic with little variation on the surface of the printed matter 30.

In this embodiment, the strain amount of the squeegee 27 is controlled to be constant, but the change characteristic of the strain amount of the squeegee 27 during screen printing is controlled to be a desired characteristic. In this case, since the amount of distortion of the squeegee 27 increases toward the tip thereof, the relationship between the portion that detects the amount of distortion of the squeegee 27 and the change in the squeegee angle of the squeegee 27 during screen printing can be grasped in advance,
By reflecting in the control data of the control controller 36, the thickness of the printed layer of the resistor to be formed becomes uneven due to the difference in the strain amount detection value caused by the difference in the strain amount detecting portion of the squeegee 27. Can be resolved.

[0031]

As described above, the present invention detects the amount of strain generated in the squeegee during the movement of the squeegee on the screen mask, and controls the squeegee when the resistor is formed based on the detected value. By eliminating the influence of the strain generated in the squeegee on the thickness of the resistor, the thickness of the printed layer of the resistor can be formed with higher accuracy than before, and the variation in the resistance value characteristics is small. Resistors for precision sensors can be formed.

[Brief description of drawings]

FIG. 1 is a side view showing a schematic configuration of a screen printing apparatus according to an embodiment of the present invention.

FIG. 2 shows a squeegee equipped with a squeegee strain detecting unit of a screen printing apparatus according to an embodiment of the present invention, FIG. 2A is an enlarged side view of a main part in which the squeegee strain detecting unit is a strain sensor, and FIG. FIG. 7A is an enlarged side view of an essential part in which the squeegee strain detection unit is composed of a pressure sensor, and FIG. 7C is an enlarged side view of an essential part in which the squeegee strain detection unit is composed of a non-contact sensor such as a laser.

FIG. 3 is a graph showing the variation width of the resistance value of the coating film layer obtained when the method of the present invention and the conventional method are specifically carried out.

FIG. 4 is a side view showing a schematic configuration of a screen printing apparatus according to a conventional example.

5A and 5B show a squeegee of a screen printing apparatus according to a conventional example, FIG. 5A is an enlarged side view of an essential part showing a normal squeegee, and FIG. 5B is an enlarged side view of an essential part showing a squeegee with distortion.

[Explanation of symbols]

 21 Squeegee speed adjusting unit 23 Pressurizing drive unit 25 Printing pressure adjusting unit 26 Squeegee holder 27 Squeegee 28 Squeegee strain detecting unit 29 Screen mask 30 Printed material 33 Gap adjusting unit 36 Control control unit 37 Paste 38 Squeegee angle adjusting unit

Claims (1)

[Claims] 1. A paste supplied onto the screen mask is spread under pressure by a squeegee moving while applying a printing pressure on a screen mask which covers a material to be printed and on which a predetermined transfer pattern is formed. In a screen printing method and a screen printing apparatus for printing and forming the predetermined transfer pattern on a material to be printed, a means capable of detecting a distortion amount of the squeegee when the squeegee moves on the screen mask while applying a printing pressure. A print control method for screen printing and a screen printing apparatus, comprising: a squeegee around the squeegee, and a control control unit for controlling the squeegee during screen printing based on a distortion amount detected by the means. .