JPH0794095A - Stripe pattern screen printing method and printing apparatus - Google Patents

Abstract

(57) [Abstract] [Purpose] It is possible to reduce the printing width in screen printing of stripe patterns. [Structure] A screen printing apparatus includes a screen 1 having a predetermined stripe pattern. The substrate 3 mounted on the auto-alignment stage 4 is supplied via the slide mechanism 6 to just below the back surface side of the screen 1. The printing squeegee 12 is driven by a driving mechanism 13 to transfer the paste supplied to the front surface side of the screen 1 to the substrate 3 located on the back surface side for printing. On the other hand, prior to the next printing, the wiping squeegee 17 is fed immediately below the screen 1 via the slide mechanism 6 to wipe off the paste residue leaked to the back surface side of the screen 1 in the direction parallel to the stripe pattern.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stripe pattern screen printing method and a stripe pattern screen printing apparatus. For example, the present invention relates to a technique for printing a stripe-shaped electrode or a partition on a plasma cell substrate.

[0002]

2. Description of the Related Art A substrate on which a stripe pattern is formed has been conventionally used as a component of various display devices, for example, a substrate for a plasma cell incorporated in a plasma addressed liquid crystal display device.
FIG. 10 shows the structure of the plasma cell substrate. Board 101
A striped electrode 102 is formed on the surface of the.
This electrode is generally formed by screen printing. The striped electrodes 102 are arranged at a predetermined pitch P, and the electrode width is set to W1. A partition 103 is formed on the electrode 102. The partition walls 103 are also formed by the screen printing method with the same pitch P. Each partition 103 has a width W2 smaller than the width W1 of the corresponding electrode. The partition wall 103 is made of an insulating material and has a structural function such as a spacer. In addition, a plasma discharge channel is formed with the electrode 102.

[0003]

In the case of assembling a plasma addressed liquid crystal display device, a plasma display device or the like using a substrate having a stripe pattern, in order to achieve high definition of a display screen, an array of stripe electrodes or partition walls is arranged. It is necessary to reduce the pitch P. Accordingly, it is necessary to prevent a short circuit between adjacent electrodes and ensure a sufficient aperture ratio of the display screen, and the width W1 of each stripe electrode must be set as thin as possible. However, when screen printing is continuously performed on the substrates that are sequentially supplied, the line width of the stripe-shaped electrodes and partition walls actually transferred to the substrate surface becomes much thicker than the line width of the screen stripe pattern. There is a problem that it will end. Further, there is a problem that the shape of the edge portion of the printed striped electrode is not smooth. Specifically, when screen printing is continuously performed, a small amount of paste leaks near the edge of the stripe pattern on the back side of the screen. When forming a fine stripe pattern by screen printing, this minute amount of leakage is transferred to the substrate side, and as a result, the electrode width and partition wall width are expanded beyond the stripe pattern design value, and irregularities are generated at the edge part. .

[0004]

Means for Solving the Problems In order to solve the above-mentioned problems of the conventional technique, the following means were taken. That is, in the stripe pattern screen printing method according to the present invention, first, a supply step of supplying the paste to the front surface side of the screen having a predetermined stripe pattern is performed. Next, a printing step is performed in which the substrate is supplied so as to face the back surface of the screen and the paste is transferred to the surface of the substrate using a squeegee through the screen. As a feature of the present invention, while repeating the printing process, a removing process of wiping off the paste residue leaked to the back surface side of the screen in a direction parallel to the stripe pattern is performed. The printing step is, for example, a step of transferring a conductive material paste onto a plasma cell substrate to print stripe electrodes. Alternatively, it is a process of transferring the insulating material paste to the plasma cell substrate and printing stripe-shaped partition walls. However, the present invention is not limited to these specific examples, and is generally applicable to the case where a stripe pattern is formed by printing on the substrate surface.

A printing apparatus was devised to carry out the above-described stripe pattern screen printing method. That is, the stripe pattern screen printing apparatus according to the present invention includes a screen having a predetermined stripe pattern, a supply unit, and
A printing unit and a removing unit are provided. The supply means supplies the substrate facing the back side of the screen. The printing means transfers the paste supplied to the front surface side of the screen to the back surface of the substrate. As a feature of the present invention, the removing means wipes off the paste residue leaked to the back surface side of the screen in a direction parallel to the stripe pattern. The removing means includes, for example, a wiping squeegee that comes into contact with the back surface side of the screen and moves in a direction parallel to the stripe pattern.

[0006]

According to the present invention, when the stripe-shaped electrodes or partition walls are continuously printed on the plasma cell substrate or the like, the paste residue leaked to the back surface of the screen is wiped off before the printing step. As a result, the transfer amount of the paste becomes constant and the protrusion from the edge of the stripe pattern disappears, making it possible to bring the line width of the printed electrodes and partition walls close to the pattern design value, making it easy to miniaturize the stripe pattern. become. When wiping the back surface of the screen, its direction is important. If the wiping process is performed in the direction orthogonal to the stripe pattern, the leaked paste residue cannot be removed efficiently. When wiped in the orthogonal direction, the paste residue moves between the stripe patterns adjacent to each other. When this is transferred to the substrate,
This causes a short circuit defect of the printed striped electrode. Therefore, in the present invention, the rear surface of the screen is wiped off in a direction parallel to the stripe pattern.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of a striped pattern screen printing apparatus according to the present invention. As shown in the figure, the printing apparatus includes a screen 1 having a predetermined stripe pattern. The predetermined stripe pattern extends in the left-right direction in the drawing. The screen 1 is attached to the screen frame 2 in a tensioned state. The screen frame 2 is fixed at a predetermined position in the printing device. The printing apparatus is provided with a supply unit and supplies the substrate 3 so as to face the back surface side of the screen 1. In this example, this supply means is composed of the automatic alignment stage 4. The automatic alignment stage 4 is mounted on a slide mechanism 6 via a stage up-and-down mechanism 5 and is movable in the left and right directions in the drawing. A pair of cameras 7 and 8 are provided above the automatic alignment stage 4. A pair of cameras 7, 8
Captures an image of the alignment mark previously formed on the substrate 3. The imaged alignment marks are captured by the image processing monitors 9 and 10. A pair of image processing monitors 9 and 1
A controller 11 is connected to 0, and based on the position information of the imaged alignment mark, the automatic alignment stage 4 is drive-controlled to automatically position the substrate 3. Therefore, the automatic alignment stage 4 can move in two directions orthogonal to each other along the horizontal plane and can rotate horizontally. Further, the automatic alignment stage 4 can be moved up and down in the vertical direction by the stage up-and-down mechanism 5.

The printing apparatus further comprises printing means, and transfers the paste supplied to the front surface side of the screen 1 to the back surface of the substrate. In this example, the printing means is composed of a printing squeegee 12 and a drive mechanism 13 for the printing squeegee. The printing squeegee 12 is connected to the drive mechanism 13 via a holder 14 and an arm 15 and is movable in the vertical and horizontal directions. A height adjusting gauge 16 of the printing squeegee 12 is attached to the top of the holder 14.

As a feature of the present invention, this printing apparatus is provided with a removing means, and the paste residue leaked to the back surface side of the screen 1 is wiped off in a direction parallel to the stripe pattern. In this example, this removing means is equipped with a wiping squeegee 17. The wiping squeegee 17 is attached to the above-mentioned slide mechanism 6 via its up-and-down mechanism 18. An adjustment gauge 19 is provided inside the wiping squeegee up / down mechanism 18.
Is incorporated to adjust the height of the wiping squeegee 17. With such a configuration, the wiping squeegee 17 comes into contact with the back surface side of the screen 1 and can move in a direction parallel to the stripe pattern.

Next, the operation of the stripe pattern screen printing apparatus shown in FIG. 1 will be described in detail with reference to FIGS. 2 and 3. FIG. 2 shows the printing process. The substrate 3 which is positioned in advance on the auto alignment stage 4 is fed via the slide mechanism 6 directly below the back surface of the screen 1 together with the stage 4. Subsequently, the substrate 3 is raised by the stage up-and-down mechanism 5 and brought into close proximity to the back side of the screen 1. On the other hand, the paste is previously supplied to the surface side of the screen 1 having the stripe pattern. In this state, the printing squeegee 12 is lowered via the drive mechanism 13 and brought into contact with the front surface side of the screen 1. The contact amount is preset by the height adjusting gauge 16. Further, the printing squeegee 12 is moved in a direction parallel to the stripe pattern via the drive mechanism 13 to transfer the paste onto the substrate 3. The printing process is performed as described above. For example, a conductive material paste can be transferred to a plasma cell substrate to print stripe electrodes. Alternatively, the insulating material paste can be transferred to the plasma cell substrate to print the stripe-shaped partition walls.

Next, the removing step will be described with reference to FIG.
After the printing process is completed, the automatic alignment stage 4 descends via the stage up-and-down mechanism 5. Further slide mechanism 6
The automatic alignment stage 4 returns to the initial position via. Here, the substrate 3 for which the printing process has been completed is taken out. While the automatic alignment stage 4 returns to the initial position, the wiping squeegee up / down mechanism 18 moves the slide mechanism 6
It is fed directly below the screen 1 via. Then, the up-down mechanism 18 is driven to raise the wiping squeegee 17 and press it against the back surface of the screen 1. The pressure contact amount is adjusted by the height adjusting gauge 19 in advance. Finally, the wiping squeegee 17 moves in a direction parallel to the stripe pattern by the slide mechanism 6 together with the up-and-down mechanism 18 to wipe off the paste residue leaked to the back surface side of the screen 1. From the above,
Prior to the next printing step, the cleaning process on the back side of the screen 1 is performed. In this example, wiping is performed every time the printing process is repeated, but the present invention is not limited to this. Generally, a removal process is performed at any time while repeating the printing process.

FIG. 4 schematically shows the planar shape of the screen 1. As described above, the screen 1 is attached with tension applied to the frame or the frame 2. A stripe pattern 20 is formed on the surface of the screen 1 by photolithography. The stripe pattern 20 is an opening because the screen mesh is exposed. The printing process and the wiping process described above are performed along the direction parallel to the stripe pattern 20 as indicated by the arrow.

FIG. 5 shows a partially enlarged sectional shape of the screen 1 cut in a direction orthogonal to the stripe pattern 20. As described above, the mesh 21 is exposed at the striped pattern 20 to form an opening. The paste 22 is held in this opening. By moving the printing squeegee in a state of being pressed against the front surface side of the screen 1, the held paste 22 is transferred to the back surface substrate. FIG. 5 shows a state before printing. When performing continuous printing, the paste residue 23 leaked near the edge of the stripe pattern 20 on the back surface side of the screen 1
Adheres. If printing is performed in this state, the paste residue 23 is also transferred to the substrate, and the desired stripe printing width cannot be obtained. That is, the print width becomes thicker than the design value. In addition, the transfer of the paste residue 23 causes unevenness to appear on the edge shapes of the printed electrodes and partition walls.

FIG. 6 shows a state after the wiping process is performed according to the present invention. As shown in the figure, the paste residue can be almost completely removed by performing the wiping process along the direction parallel to the stripe pattern 20 (the direction perpendicular to the paper surface in the figure). Therefore, if printing is performed in this state, it is possible to always transfer a fixed amount of paste 22 to the substrate, and it is possible to secure a desired printing width. Paste residue 2
Since 3 is removed, the printing edge is sharp and no unevenness occurs. Therefore, short circuit between electrodes can be effectively prevented. When wiping the back surface of the screen 1, it is important to perform it in a direction parallel to the stripe pattern. If the wiping process is performed in the direction orthogonal to the stripe pattern 20 (the direction parallel to the drawing), the paste residue cannot be removed efficiently. When the wiping squeegee is moved in the orthogonal direction, the paste residue moves between the stripe patterns. This is transferred to the substrate surface in the next printing process,
It may cause a short circuit between electrodes. In the above-described embodiment, the paste residue was removed using the wiping squeegee having the same structure as the printing squeegee.
The present invention is not limited to this. For example, the cloth may be wiped off with a cloth or paper that is dust-free or fluff-free. In this case, it is better not to impregnate the cloth or paper with the solvent. If impregnated with the solvent, the solvent will flow to the screen surface side and the viscosity of the paste will decrease. Therefore, the print width becomes thick.

Next, the effect of the present invention was confirmed by actually printing a striped electrode on the surface of the substrate using the printing apparatus shown in FIG. In this experiment, the screen 1 has a wire diameter of 23μ.
A mesh of # 325 was used for m, the bias angle was set to 30 °, and the porosity was set to 50%. Line width 70μm under these conditions
Stripe pattern of was formed on the screen. When electrode printing was performed using a nickel paste (9535M manufactured by DuPont), the line width actually printed was 90 μm. The edge shape is shown in FIG. When the wiping process is performed according to the present invention, the printed edge shape becomes sharp.

On the other hand, FIG. 8 shows an edge shape when printing is performed without performing a wiping process. As shown in the figure, the edge shape includes irregularities and is inferior in smoothness to the edge shape in FIG. Further, the line width actually printed is about 140 μm, which is twice as large as the preset stripe pattern width.

Finally, referring to FIG. 9, a plasma addressed liquid crystal display device manufactured by using the stripe pattern screen printing device shown in FIG. 1 will be described. This display device has a structure in which a liquid crystal cell 51, a plasma cell 52, and a common intermediate plate 53 interposed therebetween are laminated. The liquid crystal cell 51 is configured by using an upper glass substrate 54, and a stripe-shaped signal electrode 55 made of a transparent conductive film is formed on the inner main surface thereof. The glass substrate 54 is adhered to the intermediate plate 53 via a spacer 56 with a predetermined gap. A liquid crystal layer 57 is filled in the gap.

On the other hand, the plasma cell 52 is formed by using the lower glass substrate 58. On the inner main surface of the glass substrate 58, stripe-shaped discharge electrodes 59 orthogonal to the signal electrodes 55 are formed. The discharge electrode 59 is formed by the stripe pattern screen printing method according to the present invention, and can be miniaturized and has a sharp edge. The discharge electrode 59 alternately functions as the anode A and the cathode K. The barrier ribs 60 are formed in stripes along the discharge electrodes 59. This partition wall 60 is also formed by the stripe pattern screen printing method according to the present invention, and the line width can be made fine. The upper end of each partition wall 60 is in contact with the intermediate plate 53 and functions as a spacer. The lower glass substrate 58 is joined to the intermediate plate 53 using a frit seal 61. A hermetically sealed discharge channel 62 is formed between the two. This discharge channel 62 is divided or divided by the above-mentioned partition wall 60, and each becomes a scanning unit. An ionizable gas is enclosed in the airtight discharge channel 62. The gas species can be selected from, for example, helium, neon, argon or a mixed gas thereof.

[0019]

As described above, according to the present invention, when screen printing a stripe pattern on a substrate, the paste residue leaked to the back side of the screen is wiped off in a direction parallel to the stripe pattern. I have to. As a result, the line width of the printed electrode or partition can be reduced, and at the same time the edge shape can be sharpened. Therefore, it is possible to obtain the effect that the screen-printed electrodes and partition walls can be miniaturized. As a result, there is an effect that high definition of a plasma display or a plasma addressed liquid crystal display using the discharge electrodes or barrier ribs of the stripe pattern becomes possible.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a stripe pattern screen printing apparatus according to the present invention.

FIG. 2 is an operation explanatory diagram of the stripe pattern screen printing device shown in FIG.

FIG. 3 is likewise an operation explanatory view.

FIG. 4 is a plan view showing a stripe pattern of a screen incorporated in the stripe pattern screen printing apparatus shown in FIG.

FIG. 5 is an enlarged partial sectional view of the screen.

FIG. 6 is a partially enlarged cross-sectional view of the screen after the wiping process.

FIG. 7 is an enlarged plan view showing a shape of an electrode formed by the stripe pattern screen printing method according to the present invention.

FIG. 8 is an enlarged plan view showing a shape of an electrode formed by a conventional stripe pattern screen printing method.

FIG. 9 is a schematic cross-sectional view showing an example of a plasma addressed liquid crystal display device manufactured by using the stripe pattern screen printing device according to the present invention.

FIG. 10 is a schematic perspective view showing a substrate on which stripe electrodes and partition walls are formed.

[Explanation of symbols]

 1 Screen 2 Screen Frame 3 Substrate 4 Auto Alignment Stage 5 Stage Vertical Mechanism 6 Sliding Mechanism 12 Printing Squeegee 13 Printing Squeegee Drive Mechanism 14 Holder 15 Arm 17 Wiping Squeegee 18 Wiping Squeegee Vertical Mechanism 20 Stripe Pattern 22 Paste 23 Paste residue

Claims (5)

[Claims] 1. A supplying step of supplying a paste to a front surface side of a screen having a predetermined stripe pattern, a substrate facing the rear surface side of the screen, and a squeegee to apply the paste to the substrate through the screen. A striped pattern screen printing method, comprising: a printing step of transferring to the front surface; and a stripping step of wiping off a paste residue leaked to the back surface side of the screen in a direction parallel to the stripe pattern while repeating the printing step. 2. The stripe pattern screen printing method according to claim 1, wherein the printing step is a step of transferring a conductive material paste onto a plasma cell substrate to print a striped electrode. 3. The stripe pattern screen printing method according to claim 1, wherein the printing step is a step of transferring an insulating material paste to a plasma cell substrate to print stripe-shaped partition walls. 4. A screen having a predetermined stripe pattern, a supply means for supplying a substrate facing the back surface side of the screen, and a paste supplied to the front surface side of the screen to the substrate surface on the back surface side. A stripe pattern screen printing apparatus comprising: a printing unit for removing the paste residue and a removing unit for wiping off the paste residue leaked to the back surface side of the screen in a direction parallel to the stripe pattern. 5. The striped pattern screen printing apparatus according to claim 4, wherein the removing unit includes a wiping squeegee that comes into contact with a back surface side of the screen and moves in a direction parallel to the striped pattern.