JP2011148145A - Screen printing apparatus, method for screen printing, and method for manufacturing liquid crystal panel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a screen printing apparatus in which the viscosity of a printing paste is reduced so as to ease release of air bubbles from the printing paste, thereby enabling stable formation of a printing pattern. <P>SOLUTION: The screen printing apparatus includes; a screen plate 3 having an aperture pattern 4 placed oppositely on a substrate 1; a scraper 5 which moves along the surface of the screen plate 3 and spreads the printing paste 2 over the screen plate 3; a squeegee 7 which moves on the screen plate 3 in the printing direction and prints the printing paste 2 onto the substrate 1; and a stir promotion area 6 for promoting stir of the printing paste 2 on the scraper 5 which contacts with the printing paste 2. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

The present invention relates to a screen printing apparatus, a screen printing method, and a method for manufacturing a liquid crystal panel using these.

  The panel assembling process in a general liquid crystal panel manufacturing process includes a driving element substrate mainly formed on the basis of a glass substrate and a counter substrate which is a role of a color filter, and a predetermined bonding step, There are a process of cutting into a panel size, a process of injecting liquid crystal within the interval, and a process of sealing the liquid crystal injection port. In order to bond the substrates, a shape that surrounds the display portion of the panel with respect to the size of the panel, mainly on the counter substrate, of the driving element substrate and the counter substrate, and further has a liquid crystal injection port A seal pattern is formed. Two methods are generally used: a screen printing method and a seal dispensing method in which a pattern is drawn by nozzle scanning. Of these, the screen printing method has become the mainstream in recent years because it is excellent in productivity when the number of panels formed per substrate is large.

  In the seal pattern forming process using such a screen printing method, a printing paste is applied on a substrate through an opening pattern made up of openings corresponding to the shape of the seal pattern previously formed on the screen plate. In order to form, the above-mentioned printing paste has an opening pattern by a coating process in which the printing paste is uniformly pushed on the screen plate by a scraper that scans the screen plate at a distance, and by a squeegee that scans while pressing the screen plate surface with a predetermined pressure. The printing process of extruding from the inside and applying onto the substrate is repeated alternately. In the coating process that scans the scraper, the printing paste moves and spreads while rotating on the screen plate, so that bubbles are easily caught in the printing paste, and these bubbles are uniformly spread on the screen plate. This is a cause of the generation of voids (or pinholes when penetrating) that are portions (spaces) where there is no void. If the void, which is a portion without the print paste, is applied to the opening pattern, the amount of the print paste extruded in the printing process is insufficient, so that the shape of the formed print pattern is not stable and is formed narrower than the desired line width. There was a problem that a case of disconnection or disconnection occurred.

  For the problem of bubbles generated in the print paste as described above, the viscosity of the print paste and the thixotropy (also referred to as thixotropic property) of the paste which is a factor affecting the viscosity are important factors. The thixotropy is a property that the viscosity is lowered when the paste is stirred and the viscosity is increased in a stationary state. Screen printing is performed by effectively utilizing the thixotropy of the paste. Specifically, the viscosity of the printing paste is preferably lower with respect to the above-described bubbles because the bubbles are more easily removed than in the printing paste. On the other hand, when the viscosity is low, the ink may drip from the opening pattern of the screen plate or the scraper when it is stationary, or “smudge” may occur when the printing paste is transferred to the substrate. It becomes easy. In response to such conflicting demands on viscosity, the use of a printing paste having a large thixotropy, that is, a large difference in viscosity between stirring and stationary, mainly causes “liquid dripping” which is a problem at rest of the printing paste. And “smudge” can be made difficult to occur due to high viscosity at rest, and for the problem of bubbles, the viscosity is lowered by stirring in the coating process of the printing paste to make it easier for bubbles to escape. Can be made difficult to occur. In other words, the conflicting requirements for the viscosity are compatible by utilizing the thixotropic characteristic that the viscosity changes. However, given that problems due to air bubbles still remain, it is considered that viscosity reduction using this thixotropy is insufficient. However, to increase the stirring speed of the printing paste, it is effective to increase the coating speed of the scraper. However, if the coating speed is increased beyond the current level, a desired amount of the printing paste is filled in the opening pattern. It becomes difficult. Accordingly, it is practically difficult to take measures against bubbles by further increasing the coating speed. In order to solve the problems related to screen printing described above, in Patent Document 1, protrusions and grooves for preventing “sagging” are provided on the surface of the scraper, and there is a demand for lowering the viscosity of the printing paste even when stationary. A responding screen printing method is disclosed.

JP 2006-341965 A

  However, in the screen printing apparatus of Patent Document 1, when a low-viscosity printing paste is used, it is impossible to prevent “sagging” from the opening pattern of the screen plate and “bleeding” in which the pattern edge is shaky. It is difficult to reduce the viscosity of an extreme printing paste. Further, the effect of reducing the viscosity of the printing paste by stirring is not much different from that of a conventional flat squeegee. Accordingly, it has been impossible to fundamentally solve the problems caused by the bubbles in the printing paste described above.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to obtain a screen printing apparatus, a screen printing method, and a liquid crystal panel manufacturing method capable of stably forming a printing pattern. That is.

  In the screen printing apparatus of the present invention, a screen plate disposed oppositely on the substrate and having an opening pattern, and a scraper that moves along the surface of the screen plate and spreads the printing paste on the screen plate, And a squeegee that moves in the printing direction on the screen plate and prints the printing paste on the substrate through the opening pattern, and the scraper stirs the printing paste on the surface in contact with the printing paste. It has an agitation promoting region to promote.

  By providing the stirrer that spreads the printing paste of the screen printing device on the screen plate with a stirring acceleration area that accelerates the stirring of the printing paste, the printing paste is reduced in viscosity without increasing the moving speed of the scraper. Makes it easier for bubbles to leave.

It is the perspective view which showed the screen printing apparatus in Embodiment 1 of this invention, and the front view and side view of the scraper front-end | tip part of the principal part. It is a side view explaining the state at the time of the coating operation | movement of the screen printing apparatus in Embodiment 1 of this invention. It is a side view explaining the state at the time of printing operation of the screen printing apparatus in Embodiment 1 of this invention. It is a top view explaining the effect | action of the coating operation | movement of the screen printing apparatus in Embodiment 1 of this invention. It is the front view and side view of the scraper front-end | tip part of the principal part in the modification of Embodiment 1 of this invention. It is the front view and side view of the scraper front-end | tip part of the principal part in the modification of Embodiment 1 of this invention. It is the front view and side view of the scraper front-end | tip part of the principal part in Embodiment 2 of this invention. It is a top view explaining the effect | action of the coating operation | movement of the screen printing apparatus in Embodiment 2 of this invention. It is the front view and side view of the scraper front-end | tip part of the principal part in the modification of Embodiment 2 of this invention. It is the front view and side view of the scraper front-end | tip part of the principal part in the modification of Embodiment 2 of this invention. It is sectional drawing of the liquid crystal panel in Embodiment 3 of this invention. It is a flowchart which shows the flow of the assembly process in the manufacturing method of the liquid crystal panel in Embodiment 3 of this invention.

Embodiment 1 FIG.
Here, Embodiment 1 which is an embodiment in which the present invention is applied to a step of forming a seal pattern in a screen printing apparatus, a screen printing method, and a liquid crystal panel manufacturing method will be described. First, the configuration of the screen printing apparatus according to the first embodiment will be described with reference to FIG. Here, FIG. 1 (a) is a perspective view showing the entire screen printing apparatus, and FIGS. 1 (b) and 1 (c) are a front view and a side view of the tip of a scraper which is the main part of the present invention. It is shown. The drawings are schematic and do not reflect the exact size of the components shown. Moreover, omission of parts other than the main part of the invention and simplification of a part of the configuration are appropriately performed so that the drawings are not complicated. The same applies to the following drawings. Further, in the following drawings, the same components as those described in the previous drawings are denoted by the same reference numerals, and the description thereof is omitted.

  In FIG. 1, 1 is a substrate to be printed, 2 is a printing paste to be printed, 3 is a screen plate, 4 is an opening pattern formed on the screen plate 3, 5 is a scraper, and 6 is a printing paste formed on the scraper. The agitation promoting region, 7 is a squeegee, and 8 is a stage for holding the substrate. As shown in FIG. 1, the screen printing apparatus according to the first embodiment includes a stage 8 that holds a substrate 1, a screen plate 3 that is disposed on the top of the substrate 1, and a printing paste 2 on the screen plate 3. And a squeegee 7 for printing the printing paste 2 spread on the screen plate 3 on the surface of the substrate 1 through the opening pattern 4. The scraper 5 is in contact with the printing paste 2. An agitation promoting region 6 that promotes agitation of the printing paste 2 is provided on the surface of the portion to be performed. In the drawing, the printing paste 2 has already been applied on the screen plate 3 through a coating operation by the scraper 5. Further, in the first embodiment, the scraper 5 and the squeegee 7 with respect to the X direction and Y direction in the figure (the direction along the surface of the screen plate 3 and corresponding to the longitudinal direction and the short direction in the frame 3 respectively). Are arranged in the direction along the Y direction. The screen printing apparatus includes a moving mechanism that moves the squeegee 7 and the scraper 5 horizontally during the printing operation and moves the squeegee 7 up and down to change the distance from the screen plate 3, and the substrate 1 before and after printing. A stage moving mechanism for moving the stage 8 to the loading / unloading position at the time of unloading and the like, and a substrate transfer mechanism for loading / unloading the substrate 1 between the stage 8 and the outside of the apparatus are also provided. Illustration and description are omitted.

  As shown in FIG. 1, the screen plate 3 is composed of a frame 3a made of a metal such as aluminum and a screen 3b having an opening pattern 4 attached to the frame 3a. There are a case where it is constituted by a metal mesh and an emulsion layer, and a case where it is constituted by a very thin metal plate. In Embodiment 1, any configuration may be used. The opening pattern 4 was an opening pattern corresponding to a seal pattern used for a general liquid crystal panel. Further, the opening patterns 4 are arranged in a matrix so that a plurality of liquid crystal panels can be obtained, in this case, for example, arranged in 4 columns and 4 rows.

  Then, the structure of the scraper 5 provided with the stirring promotion area | region 6 which accelerates | stimulates stirring of the printing paste 2 which is the principal part of this invention is demonstrated in detail using FIG.1 (b) and FIG.1 (c). FIGS. 1B and 1C are enlarged views of the vicinity of the lower portion of the scraper 5, particularly the portion that contacts the printing paste 2. As shown in FIG. 1 (b), an agitation promoting region 6 is formed so as to be surrounded by a dotted line on the surface of the scraper 5 at the portion in contact with the printing paste 2. The stirring promoting region 6 is desirably formed in a region wider than the entire region where the printing paste 2 contacts at least during the coating operation by the scraper 5. In this Embodiment 1, in this stirring promotion area | region 6, the fine uneven | corrugated shape is formed in the surface, and the contact area which contacts the printing paste 2 is enlarged compared with the plane. More specifically, the fine protrusions 16 as shown in FIGS. 1B and 1C are regularly arranged over almost the entire stirring promoting region 6. The protrusions 16 are spherical protrusions, and the diameters on the surface of the scraper 5 are arranged with the same size of protrusions selected from a range of about 0.5 mm to 5 mm at intervals substantially equal to the diameter. That is, in the stirring promotion region 6, the protrusions 16 are uniform in size and are arranged at a uniform density. Note that the density here refers to the arrangement density in the number of protrusions 16, and specifically, the number of centroid positions in the pattern shape on the surface of the scraper 5 of the protrusions 16 that are uneven, the unit in the stirring promoting region 6. What is estimated per area will be used as a measure of density.

  Next, the operation of the screen printing apparatus according to the first embodiment will be described with reference to the side view of the apparatus side face (direction perpendicular to the printing direction) in FIGS. 2 and 3. First, as shown in FIG. 2, the scraper 5 moves in the (+ X) direction in the drawing, that is, in the direction of the arrow CT in the drawing, which is parallel to the longitudinal direction of the screen plate 3 along the surface of the screen plate 3. By moving while keeping a predetermined distance from the surface of the plate 3, a coating operation for spreading the printing paste 2 on the screen plate 3 is performed. Thereby, the printing paste 2 is spread almost uniformly on the screen plate 3 in an area including at least a portion where the opening pattern 4 is arranged. Moreover, in FIG. 1, each structure was demonstrated with drawing which separately arrange | positioned the scraper 5 which performs a coating | coating operation | movement, and the squeegee 7 which prints separately in the position. Of course, they may be arranged separately as shown in FIG. 1 and provided with independent moving mechanisms, but in the first embodiment, as a specific configuration, as shown in FIG. 2, the scraper 5 and the squeegee 7 are provided. Are held by a common holding unit 15, and the holding unit 15 is moved horizontally by a moving mechanism (not shown). In addition, the holding unit 15 moves the scraper 5 and the squeegee 7 in the lowering (in the (−Z) direction) direction of the scraper 5 and the squeegee 7 in the upward (in the (+ Z) direction) direction. It is equipped with a moving mechanism that switches between them alternately. Before the coating operation shown in FIG. 2, the holding unit 15 performs the lowering operation of the scraper 5 in which the scraper 5 is brought close to the surface of the screen plate 3 at a predetermined interval, and the rising operation of the squeegee 7 for retracting the squeegee 7. Thus, preparation for a coating operation in which only the scraper 5 functions is performed.

  Next, as shown in FIG. 3, the squeegee 7 has a direction indicated by an arrow PR in the drawing (−X) direction, that is, a direction parallel to the longitudinal direction of the screen plate 3 along the surface of the screen plate 3. As the printing direction, the printing paste 2 spread on the screen plate 3 is applied to the surface of the substrate 1 through the opening pattern 4 by moving while being pressed against the surface of the screen plate 3. More specifically, after the printing paste 2 spread on the screen plate 3 is filled in the opening pattern 4, the filled printing paste 2 is transferred to the surface of the substrate 1 and corresponds to the shape of the opening pattern 4. Printing is performed. At the time of printing, the screen plate 3 or the stage 8 is moved in advance, so that the screen plate 3 and the stage 8 are brought close to each other just before contact, and the surface of the substrate 1 disposed below the screen plate 3 and the screen plate 3 is also used. Similarly, the screen plate 3 and the surface of the substrate 1 are arranged to face each other. Since the screen plate 3 and the substrate 1 need only be moved close to each other at least during the operation of the squeegee 7, it may be immediately before the operation of the squeegee 7 or before the coating operation by the scraper 5. Also good. Further, after the proximity movement of the screen plate 3 and the substrate 1 and before the printing operation of FIG. 3, the squeegee 7 is pressed against the surface of the screen plate 3 by the holding unit 15, and a predetermined amount against the surface of the substrate 1 or the stage 8. The descending operation of the squeegee 7 close to the interval and the ascending operation of the scraper 5 for retracting the scraper 5 are performed, and the preparation for the printing operation in which only the squeegee 7 functions is performed.

  Next, the operation of the screen printing apparatus and the screen printing method according to the first embodiment will be described with reference to FIG. FIG. 4 is a schematic diagram showing a state in the vicinity of the scraper 5 during the coating operation by the scraper 5, and FIG. 4 (a) is viewed from the side of the coating operation direction (arrow CT in the drawing), FIG. 4B corresponds to the case of viewing from the upper surface side, that is, the (+ Z) direction in the drawing, in the section AB in FIG. 4A. As shown in FIG. 4 (a), during the coating operation by the scraper 5, the printing paste 2 on the surface of the screen plate 3 proceeds while being rotationally stirred as indicated by the arrow R1 in the figure. Operation is performed. Since the viscosity of the printing paste 2 during the coating operation depends on the stirring speed of the printing paste 2, in the case of a general conventional scraper, the viscosity of the printing paste is reduced by the rotational stirring effect indicated by the arrow R1 in the figure. descend. However, in the case of the scraper 5 according to the first embodiment, the stirring promotion region 6 in which fine protrusions 16 are regularly arranged is provided in a region in contact with the printing paste 2 of the scraper 5. A rotational stirring motion as shown by the middle arrow R2 is added. Further, the rotational stirring movement as shown by the arrow R2 in the figure is as shown in FIG. 4 (b) in addition to the same rotation axis in the Y direction as the arrow R1 in the figure as shown in FIG. 4 (a). Some have a Z axis rotation axis. Furthermore, since it is the spherical protrusion 16, the motion of rotational agitation about various directions is complicated. As described above, since the agitation movement of the printing paste 2 is promoted by the agitation promoting region 6, the overall agitation speed of the printing paste 2 is increased, and the action of reducing the viscosity of the printing paste 2 by agitation is also improved. Furthermore, the lower the viscosity of the printing paste 2, the easier it is for bubbles to escape from the printing paste 2. This facilitates the removal of bubbles and suppresses the occurrence of problems due to bubbles.

  The agitation promoting effect of the printing paste 2 by the agitation promoting region 6 is caused by the effect that the flow of the printing paste 2 on the surface of the scraper 5 is dispersed by the uneven shape and the effect that the contact area with the surface of the scraper 5 itself is increased. . Further, in order to substantially obtain the stirring promoting effect, it is necessary to form the above-mentioned uneven shape over almost the entire stirring promoting region 6, and the fine array arranged as in the first embodiment is required. When the concavo-convex shape is formed by the projection 16 or the like, it is necessary to form a plurality of matrices at least vertically and horizontally.

  As described above, in the screen printing apparatus and the screen printing method according to the first embodiment, the scraper 5 that spreads the printing paste 2 on the screen plate 3 includes the stirring promoting region 6 that promotes the stirring of the printing paste 2. This makes it possible to reduce the viscosity of the printing paste 2 without increasing the moving speed of the scraper 5 and to easily remove the bubbles from the printing paste.

  Furthermore, in the screen printing apparatus and the screen printing method of the first embodiment, since the fine protrusions 16 formed in the stirring promotion region 6 are regularly arranged and formed, the stirring promotion effect is effective in the stirring promotion region 6. It becomes uniform over the whole. Moreover, since all the protrusions 16 are formed in the same size, the stirring promoting effect is similarly uniform over the entire stirring promoting region 6. Further, since the protrusions 16 are formed in a curved surface, the stirring by the rotation of the printing paste 2 formed in the stirring promoting region 6 occurs smoothly and the stirring speed is increased. Furthermore, the spherical surface is advantageous in that stirring having a multi-directional rotation axis occurs and the formation of the uneven shape is relatively easy.

  Further, the stirring promoting region 6 according to the first embodiment has been described as an example in which the protrusions 16 are aligned and formed at a uniform density, but may be arranged at random positions. However, the arrangement and the uniform density are preferable in that the stirring is performed uniformly as described above. Further, the protrusions 16 are discretely arranged at a distance, but the protrusions 16 may be densely arranged without a gap. About such a modification, the front view and side view of a scraper front-end | tip part are shown to Fig.5 (a) and FIG.5 (b). As shown in the figure, in this modification, the scraper 5a is provided with a stirring acceleration region 6a in which the protrusions 16 are densely arranged without a gap. Further, the distance between the protrusions 16 may be reduced to increase the density, and no flat surface may be formed between the protrusions 16 in the stirring promoting region 6. You may arrange | position the protrusion of a different diameter so that it may be filled. By arranging the protrusions 16 without any gaps in this way, the entire surface of the stirring acceleration region 6a is formed by a curved surface, and stirring is not hindered by the rotation of the printing paste 2, and the stirring speed is improved. be able to. Moreover, although the case where the protrusions 16 are arranged as an example of the uneven shape has been described as an example, a hollow 26 made of, for example, a spherical surface may be disposed instead of the protrusion 16. About such a modification, the front view and side view of a scraper front-end | tip part are shown to Fig.6 (a) and FIG.6 (b). As shown in the figure, in this modification, the scraper 5b is provided with a stirring acceleration region 6b in which a spherical recess 26 is arranged. Even in such a configuration, substantially the same stirring effect as in the case of the spherical protrusion 16 can be obtained, and since it is spherical, it is relatively easy to form an uneven shape.

  Moreover, the form of the stirring promotion area | region in this invention is not restricted to these forms, You may change a shape, a magnitude | size, a density, an arrangement | sequence, etc. suitably. Furthermore, if at least a fine uneven shape is formed, the effect of promoting agitation can be obtained in the same manner. Therefore, various other uneven shapes may be used, and the same effect as in the first embodiment described above is obtained. be able to. For example, the concavo-convex shape is not necessarily limited to a regular arrangement, and may be any concavo-convex shape formed to a uniform density with some variation, and a concavo-convex shape made of a rough surface such as a uniformly treated blast surface It does not matter.

Embodiment 2. FIG.
In the first embodiment, the screen printing apparatus having the scraper 5 provided with the stirring promoting region 6 in which the protrusions 16 having the same size are aligned has been described. Since the protrusions 16 that are concave and convex provided in the stirring promotion region 6 of the first embodiment are the same size protrusions 16, all the protrusions 16 played the same role of stirring promotion. In the second embodiment, a screen printing apparatus having a scraper having an agitation accelerating region having at least two different concavo-convex shapes each having a different role will be described. Note that the change from the first embodiment in the second embodiment is only the difference in the configuration of the stirring promoting region provided in the scraper, and other printing mechanisms and the like may be the same configuration. Hereinafter, the configuration of the agitation promoting region, which is a changed portion with respect to the first embodiment, will be mainly described, and description of the same configuration as that of the first embodiment will be appropriately omitted.

  First, the scraper 5c provided with the stirring promotion area | region 6c which is the characteristic part in this Embodiment 2 is demonstrated using FIG. Here, FIG. 7 (a) and FIG. 7 (b) show a front view and a side view of the tip of the scraper 5c, which is the main part of the present invention, respectively. As shown in FIG. 7A, an agitation promoting region 6c is formed so as to be surrounded by a dotted line on the surface of the scraper 5c that contacts the printing paste 2. Also in the stirring promotion region 6c of the second embodiment, a fine uneven shape is formed on the surface. More specifically, as shown in FIGS. 7A and 7B, the stirring promotion region Fine protrusions 16a are regularly arranged on the lower part of 6c, and a groove 26a extending in the vertical direction in the vertical direction is formed as a fine recess between the fine protrusions 16a on the upper part of the stirring promoting region 6c. It differs in that it is formed. The protrusion 16a may have the same form as that of the protrusion 16 in the first embodiment. The protrusion 16a is a spherical protrusion, and the diameter on the surface of the scraper 5c is the same size selected from the range of about 0.5 mm to 5 mm. The protrusions are arranged at an interval substantially equal to the diameter. That is, in the stirring promotion region 6c, the protrusions 16a are uniform in size and are arranged at a uniform density.

  Next, the operation of the screen printing apparatus and the screen printing method according to the second embodiment will be described with reference to FIG. FIG. 8 is a schematic diagram showing a state in the vicinity of the scraper 5c during the coating operation by the scraper 5c, and corresponds to the case when viewed from the side with respect to the coating operation direction (arrow CT in the figure). As shown in FIG. 8, during the coating operation by the scraper 5c, the printing paste 2 on the surface of the screen plate 3 is basically rotated and agitated by the scraper 5c as shown by the arrow R1 in the figure as in the first embodiment. Then, the coating operation is performed. In the case of the scraper 5c according to the second embodiment, the agitation promoting region 6 in which fine protrusions 16 are regularly arranged is provided in a region in contact with the printing paste 2 of the scraper 5c. In FIG. 5, a rotational stirring motion as indicated by an arrow R2 in the figure is added. Due to the rotational stirring effect indicated by the arrow R2 in the figure, the viscosity of the printing paste 2 decreases. Furthermore, in the second embodiment, bubbles 9 generated in the printing paste 2 are formed in the upper portion of the stirring promoting region 6c by the grooves 26a extending in the vertical direction as shown in FIG. It moves to the upper part of the scraper 5 c through the inside of the printing paste 2 inside the groove 26 a and is detached from the surface of the printing paste 2. Further, in the cross section of the groove 26a, the inclined portion 27a is formed on the lower surface in contact with the printing paste 2 as shown in FIG. 8, so that the printing paste 2 can easily move upward. The separation of the bubbles 9 at the upper part in the groove 26a is promoted. Moreover, since the groove | channel 26a is also uneven | corrugated shape, of course, it has the effect which accelerates | stimulates stirring of the printing paste 2, and contributes also to the viscosity fall of the printing paste 2. FIG.

  As described above, in the screen printing apparatus and the screen printing method according to the second embodiment, as in the screen printing apparatus and the screen printing method according to the first embodiment, the scraper that spreads the printing paste 2 on the screen plate 3. By providing the agitation promoting region 6c that promotes the agitation of the printing paste 2 in 5c, the viscosity of the printing paste 2 can be reduced without increasing the moving speed of the scraper 5c, and bubbles can be easily detached from the printing paste. can do.

  Furthermore, in the screen printing apparatus and the screen printing method according to the second embodiment, two different uneven shapes of the protrusion 16a provided at the lower portion of the scraper 5c and the groove 26a provided at the upper portion and extending in the longitudinal direction in the vertical direction are provided. By providing the agitation promoting region 6c having the above, the printing paste 2 is reduced in viscosity due to the uneven shape such as the protrusions 16a and the grooves 26a, and the vertical direction provided at the upper part of the agitation promoting region 6c extends in the longitudinal direction. By guiding the printing paste 2 to the upper part of the scraper 5c by the groove 26a, the separation of the bubbles can be promoted. As a result, it is possible to obtain a screen printing apparatus and a screen printing method that have a high bubble separation effect.

  Another form may be sufficient as the stirring promotion area | region which has two different uneven | corrugated shapes. Another example of the scraper provided with the stirring acceleration region having two different uneven shapes will be described with reference to FIG. FIG. 9A and FIG. 9B show a front view and a side view of the tip portion of the scraper provided with the stirring promotion region having these two types of different uneven shapes. As shown in the figure, in this modified example, the scraper 5d is provided with an agitation promoting region 6d. In the agitation promoting region 6d, there are two types of fine projections 16b and fine projections 16c having different diameters. Both the protrusion 16b and the protrusion 16c are spherical protrusions, and the diameter of the surface of the scraper 5d is, for example, approximately 5 mm for the protrusion 16b and approximately 1 mm for the protrusion 16c, and the protrusion 16b is the protrusion. The protrusion is larger than that of 16c. Further, as the arrangement, the small protrusion 16c is arranged between the large protrusions 16b, and more specifically, the central position surrounded by the four large protrusions 16b with respect to the four large protrusions 16b arranged close to each other. In this rule, one small protrusion 16c is arranged at regular intervals.

  The operation of the modified example of the second embodiment including the scraper 5d provided with the agitation promoting region 6d having two different diameters of the protrusion 16b and the protrusion 16c shown in FIG. 9 will be described. During the coating operation of the printing paste 2, the printing paste 2 is agitated by the concavo-convex shape formed by the protrusions 16b and the protrusions 16c, and the stirring acceleration region 6d is agitated by the printing paste 2 as in the first or second embodiment. Contribute to the promotion of Moreover, although the two types of large and small protrusions 16b and protrusions 16c promote the agitation of the printing paste 2, the printing paste 2 has a relatively wide area range from the vicinity of the protrusions 16b due to the large protrusions 16b. The relatively narrow region in the vicinity of the protrusion 16c is stirred by the small protrusion 16c. Since complicated stirring occurs in different ranges as described above, the stirring speed of the printing paste 2 is increased, and the viscosity reduction of the printing paste 2 is promoted. Furthermore, the fine paste by the small protrusions 16c plays a role of promoting the decrease in the viscosity of the printing paste 2, and the large protrusions 16b make the stirring within the stirring promotion region 6d to easily release the bubbles in the print paste 2. Different role assignments by two different uneven shapes, such as the role of guiding to the peripheral part of the two, are performed, and the detachment of bubbles can be promoted.

  As for the modification of the second embodiment described with reference to FIG. 9, as shown in FIG. 10, the number of small protrusions surrounded by large protrusions may be increased. FIG. 10A and FIG. 10B are a front view and a side view of the tip of the scraper 5e provided with the stirring promotion region 6e in which the number of small protrusions is increased. As shown in the figure, in this modification, the number of small protrusions 16d surrounded by the large protrusions 16b is increased in the stirring promoting region 6e. Specifically, one of the four protrusions 16b surrounded by the large protrusions 16b is increased. A plurality of small projections 16d are arranged per region, and here, as an example, four small projections 16d are arranged. Except for this change, the configuration may be the same as that of the modified example of the second embodiment described with reference to FIG.

  As described with reference to FIG. 9, the small protrusions mainly play a role of performing fine stirring and promoting a decrease in the viscosity of the printing paste 2. Accordingly, since the arrangement ratio of the small protrusions 16d in the stirring promoting region 6e is increased, stirring is more intense and the effect of reducing the viscosity of the printing paste 2 is increased. Subsequently, in this way, the printing paste 2 that has a greater viscosity drop and is easier to remove bubbles is stirred by the large protrusions 16b throughout the stirring promoting region 6e. As a result, the bubbles in the printing paste 2 are guided to the peripheral portion of the printing paste 2 where the bubbles can be easily detached, and the effect of promoting the separation of the bubbles can be further improved. Note that the scraper 5e described with reference to FIG. 10 is an example, and the number and size of the small protrusions 16d may be changed as appropriate, and the number and size of the large protrusions 16b may be changed. As a guide for the size, a range of about 0.5 mm to 3 mm is desirable for the small projection 16d, and a range of about 3 mm to 10 mm is desirable for the large projection 16b, but these ranges are not necessarily limited.

  Furthermore, the stirring promoting regions having different uneven shapes are not limited to the configuration described above, but are shapes (projections or depressions) in each of the embodiments described in the first embodiment, the second embodiment, and the modifications thereof. In addition, the size, density, arrangement, and the like may be appropriately changed and may be arranged in combination, and different roles may be assigned to different uneven shapes.

Embodiment 3 FIG.
Subsequently, Embodiment 3 which is an embodiment in which the present invention is applied to a method for manufacturing a liquid crystal panel will be described. First, the structure of the liquid crystal panel manufactured by the liquid crystal panel manufacturing method of the third embodiment will be described with reference to FIG. Here, the TFT (T hin F ilm T ransistor ) mode liquid crystal panel will be described as an example. As shown in the figure, the liquid crystal panel 200 includes a switching element substrate 210, a color filter substrate 220, and a liquid crystal 230 filled between the switching element substrate 210 and the color filter substrate 220.

  The switching element substrate 210 includes an alignment film 212 that aligns the liquid crystal 230 on one surface of the glass substrate 211, a pixel electrode 213 that is provided below the alignment film 212 and applies a voltage for driving the liquid crystal 230, and the pixel electrode 213. A switching element 214 such as a TFT for supplying voltage, an insulating film 215 covering the switching element 214, a terminal 216 for receiving a signal supplied to the switching element 214 from the outside, and a signal input from the terminal 216 for transmitting to the counter electrode A transfer electrode 217 and the like are included. In addition, a polarizing plate 231 is provided on the other surface of the glass substrate 211. On the other hand, the above-described color filter substrate 220 is disposed under one of the alignment film 222 for aligning the liquid crystal 230 on one surface of the glass substrate 221 and the alignment film 222, and an electric field between the pixel electrode 213 on the switching element substrate 210. A common electrode 223 for driving the liquid crystal 230, a color filter 224 provided under the common electrode 223, a light shielding layer 225, and the like. In addition, a polarizing plate 232 is provided on the other surface of the glass substrate 221.

Further, the switching element substrate 210 and the color filter substrate 220 are bonded together with a seal pattern 233 interposed therebetween. Further, the transfer electrode 217 and the common electrode 223 are electrically connected by a transfer material 234, and a signal input from the terminal 216 is transmitted to the common electrode 223. In addition, the control board 235 liquid crystal panel 200 for generating a drive signal, FFC for electrically connecting the control board 235 to the terminal 216 (F lexible F lat C able ) 236, without a backlight unit (shown as a light source ) Etc.

  The liquid crystal panel 200 operates as follows. For example, when an electric signal is input from the control substrate 235, a driving voltage is applied to the pixel electrode 213 and the common electrode 223, and the molecular direction of the liquid crystal 230 is changed in accordance with the driving voltage. The light emitted from the backlight unit is transmitted or blocked to the outside through the switching element substrate 210, the liquid crystal 230, and the color filter substrate 220, whereby an image or the like is displayed on the liquid crystal panel 200.

The liquid crystal panel 200 is an example and may have other configurations. Operation mode of the liquid crystal panel 200, and TN (T wisted N ematic) mode, STN (S upper T wisted N ematic) mode may be a ferroelectric liquid crystal mode, etc., the driving method may be a simple matrix or an active matrix, etc. . The present invention is not limited to a transmissive liquid crystal panel using the pixel electrode 213 as a transmissive electrode, and may be a reflective liquid crystal panel using the pixel electrode 213 as a reflective electrode, or a transflective liquid crystal panel using both the reflective electrode and the transmissive electrode. Further, a common electrode 223 provided on the color filter substrate 220 is disposed on the switching element substrate 210 side, and a horizontal electric field method is used in which an electric field is applied to the pixel electrode 213 in the horizontal direction with respect to the substrate surface to operate the liquid crystal 230. The LCD panel that was used may be used.

  Next, a method for manufacturing the liquid crystal panel of the third embodiment will be described. The manufacturing method of the switching element substrate 210 and the color filter substrate 220 may be simply described because a general method may be used. The switching element substrate 210 has a switching element 214, a pixel electrode 213, a terminal 216, and a transfer electrode 217 formed on one surface of the glass substrate 211 by repeatedly using a pattern forming process such as film formation, patterning by photolithography, and etching. Manufactured by forming. Similarly, the color filter substrate 220 is manufactured by forming the color filter 224 and the common electrode 223 on one surface of the glass substrate 221. Further, the liquid crystal panel is arranged in parallel with the short and long sides of the glass substrates 211 and 221 so that a large number of liquid crystal panels 200 can be efficiently manufactured from the pair of switching element substrates 210 and the color filter substrate 220. They are regularly arranged.

  Subsequently, a characteristic assembly process in the third embodiment will be described with reference to a flowchart shown in FIG. First, in the substrate cleaning process, the switching element substrate 210 on which the pixel electrode 213 is formed is cleaned (S1). Next, in the alignment film material application step, an alignment film material is applied and formed on one surface of the switching element substrate 210 (S2). In this step, for example, an alignment film material made of an organic film is applied by a printing method, and is baked and dried by a hot plate or the like. Thereafter, the alignment film material is rubbed in a rubbing process, and the alignment film material surface is subjected to an alignment treatment to form an alignment film 212 (S3). Similarly to S1 to S3, the alignment film 222 is formed on the color filter substrate 220 on which the common electrode 223 is formed by washing, applying an alignment film material, and rubbing.

  Subsequently, in the sealing material application process, the screen printing apparatus described in Embodiment 1 uses the sealing material as a printing paste, the switching element substrate 210 or the color filter substrate 220, which is a liquid crystal panel substrate, as a substrate to be printed, and the liquid crystal A seal material is applied to one surface of the panel substrate to form a seal pattern 233 (S4). In this step, the seal pattern 233 arranged around the liquid crystal panel also has a short side and a long side corresponding to the imposition of the liquid crystal panel regularly arranged in parallel with the short side and the long side of the glass substrates 211 and 221. It is formed by regularly arranging in parallel. Moreover, it is necessary to be concerned about the destabilization of the seal pattern shape caused by the pinhole generated by the bubbles, using the screen printing apparatus having the scraper provided with the stirring acceleration region for promoting the stirring described in the first embodiment. Therefore, the conventional coat operation condition may be used without particularly increasing the moving speed of the scraper. In addition, since the specific printing process method by the screen printing apparatus is as described in the first embodiment, the description is omitted here.

  Next, in the transfer material application process, the transfer material 234 is applied to one surface of the switching element substrate 210 or the color filter substrate 220 (S5). In the spacer spraying step, spacers are sprayed on one surface of the switching element substrate 210 or the color filter substrate 220 (S6). This step is performed, for example, by dispersing the spacers by a wet method or a dry method. In the case of using a columnar spacer formed by patterning an organic resin film as the spacer, it is desirable to form it on either the switching element substrate 210 or the color filter substrate 220 before the assembly process, In that case, this spacer spraying step can be omitted. Thereafter, in the bonding step, the switching element substrate 210 and the color filter substrate 220 are bonded together (S7). Subsequently, in the seal curing step, the seal pattern 233 is completely cured in a state where the switching element substrate 210 and the color filter substrate 220 are bonded together (S8). This step is performed, for example, by applying heat according to the material of the seal pattern 233 or by irradiating ultraviolet rays. Next, in the cell dividing step, the bonded substrates are disassembled into a large number of individual cells (S9). In the liquid crystal injection step, liquid crystal is injected from the liquid crystal injection port into each cell (S10). This step is performed, for example, by filling the liquid crystal 230 by vacuum injection from the liquid crystal injection port. Further, in the sealing step, the liquid crystal inlet is sealed (S11). This step is performed, for example, by sealing with a photocurable resin and irradiating with light.

  The above-described steps from S7 to S11 bonding to liquid crystal sealing have been described by taking as an example a vacuum injection method in which liquid crystal is injected from an injection port in a normal vacuum. However, as another liquid crystal injection method, the shape of the seal pattern 233 having no injection port is formed, and the liquid crystal 230 is formed in a droplet state on the switching element substrate 210 or the color filter substrate 220, and the dropped liquid crystal 230 is formed. Alternatively, a method of curing the seal pattern 233 after bonding the switching element substrate 210 and the color filter substrate 220 so as to sandwich the substrate, a so-called liquid crystal dropping (ODF) method may be used. Finally, in the polarizing plate attaching step, the polarizing plates 231 and 232 are attached to the cells (S12), and in the control substrate mounting step, the control substrate 235 is mounted (S13), thereby completing the liquid crystal panel 200.

  In the manufacturing method of the liquid crystal panel of the third embodiment described above, as described above, in the sealing material application process, the screen printing apparatus having the scraper provided with the stirring promoting region for promoting the stirring described in the first embodiment is used. By forming the seal pattern 233, there is no instability of the seal pattern shape due to pinholes, and there is no need to particularly increase the moving speed of the scraper. There is no occurrence of instability of the seal pattern shape. Therefore, the stable seal pattern 233 can be formed. As a result, it is possible to prevent a decrease in yield due to generation of defective products due to a defective seal pattern shape in the manufacturing process of the liquid crystal panel 200 and a decrease in reliability due to a thin seal pattern shape in the manufactured liquid crystal panel 200. can do. Accordingly, the number of substrates that become defective products and are dropped in the process can be reduced, leading to a reduction in raw material costs. Furthermore, since unnecessary processing can be reduced by recreating a substitute for a defective product, energy consumption for manufacturing can be reduced.

  In the third embodiment, the liquid crystal display panel manufacturing method using the screen printing apparatus and the screen printing method of the first embodiment in the seal coating process has been described. However, instead of the screen printing apparatus and the screen printing method of the first embodiment, the screen printing apparatus and the screen printing method described in the modification of the first embodiment and the modifications of the second and second embodiments are used. Even in this case, the same effect as in the third embodiment can be obtained.

  In the first embodiment, the second embodiment, the third embodiment, and the modifications thereof, the present invention is applied to a screen printing apparatus, a screen printing method, or a liquid crystal panel manufacturing method used in a sealing material forming process in a liquid crystal panel. Although the case has been described as an example, it is merely an example, and if it has a process that needs to form a paste pattern using screen printing, for example, an electronic paper, an organic EL display device, or the like other than a liquid crystal panel The screen printing apparatus and the screen printing method used in the process of forming the paste pattern in the display apparatus may be used, and the screen printing apparatus and the screen printing for any substrate to be used for screen printing are not limited to the manufacturing process of the display apparatus. It can be applied to the method and the same effect can be obtained. It is. Further, the printing paste is not limited to the sealing material, and can be applied to any printing paste having thixotropy and used for screen printing.

  The above description describes the embodiment of the present invention, and the present invention is not limited to the above embodiment. Moreover, those skilled in the art can easily change, add, and convert each element of the above-described embodiments within a range where the effects of the present invention can be obtained.

1 substrate, 2 printing paste, 3 screen plate, 4 opening pattern,
5, 5a, 5b, 5c, 5d, 5e scraper,
6, 6a, 6b, 6c, 6d, 6e Stirring promotion area, 7 Squeegee,
16, 16a, 16b, 16c, 16d protrusion, 26 depression, 26a groove,
200 Liquid crystal panel, 233 Seal pattern.

Claims (13)

  A screen plate having an opening pattern arranged oppositely on the substrate, a scraper that moves along the surface of the screen plate and spreads the printing paste on the screen plate, and moves in the printing direction on the screen plate A squeegee that prints the printing paste on the substrate through the opening pattern, and the scraper includes a stirring acceleration region that promotes stirring of the printing paste on a surface in contact with the printing paste. A screen printing apparatus characterized by that.   The screen printing apparatus according to claim 1, wherein a fine uneven shape is formed on the surface of the scraper in the stirring promotion region.   2. The screen printing apparatus according to claim 1, wherein protrusions or depressions are regularly arranged on the surface of the scraper in the stirring promotion region.   The screen printing apparatus according to claim 3, wherein the protrusions or depressions are arranged at a uniform density.   The screen printing apparatus according to claim 3, wherein the protrusions or the depressions are arranged without a gap.   6. The screen printing apparatus according to claim 3, wherein the protrusion or the depression is formed by a curved surface.   The screen printing apparatus according to claim 6, wherein the protrusion or the depression is formed of a spherical surface.   The screen printing apparatus according to any one of claims 3 to 7, wherein the protrusions or the depressions have the same size.   The screen printing apparatus according to any one of claims 3 to 7, wherein the projections or depressions are of two sizes, large and small, and the small projections or depressions are arranged between the large projections or depressions. .   The screen printing apparatus according to claim 3, wherein the protrusion or the depression includes a protrusion provided at a lower portion of the stirring promotion region and a groove extending in a vertical direction provided at the upper portion of the stirring promotion region.   A screen printing method using the screen printing apparatus according to claim 1.   The screen printing apparatus according to claim 1, wherein the substrate is a liquid crystal panel substrate, and the printing paste is a sealing material.   A method for manufacturing a liquid crystal panel, comprising the step of forming a sealing material using the screen printing apparatus according to claim 12.

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