JP3155067B2 - Powder spraying device and spraying method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a powder dispersing apparatus, for example, an electro-optical device using a liquid crystal, in particular, a fine powder of about several .mu.m to 10 .mu.m between two transparent substrates forming a liquid crystal display panel. The present invention relates to an apparatus for dispersing powder used for interposing as a spacer.

[0002]

2. Description of the Related Art The prior art to which the present invention is applied will be described by taking as an example the case of manufacturing a liquid crystal display panel.

A liquid crystal display panel selectively applies an electric field to appropriate portions of two transparent substrates filled with liquid crystal in the middle,
It forms a panel portion of a liquid crystal display device that displays information such as specific figures and characters, and fine particles are interposed between two transparent substrates as spacers to keep a uniform gap between them. There is a need. Conventionally, as a method of inserting the spacer, a method of spraying fine powder in a dispersed state on a substrate from a nozzle has been adopted (for example, Japanese Patent Application Laid-Open No. 64-76031).

The fine powder used for the spacer has an extremely small particle size of about several μm to 10 μm, but directly affects the performance of the liquid crystal display panel. Industrial requirements include satisfying various requirements for particle size uniformity, etc., and the fact that the powder to be sprayed is agglomerated and formed into secondary particles so that the spacing between substrates cannot be kept uniform and is sufficiently dispersed. Although it is a problem in practice, together with these, the well-dispersed powder is sprayed so as not to be unevenly distributed in the powder spraying area, but to be present in whole and in part on average. Is desired.

[0005] request for such average spraying, to not a few for the particular design number that is set in one For example speaking, within the range of, for example 1 mm 30 to 200 or so per ² 1
It is also understood from the fact that a variation of about 0 or less is allowed, and a product that cannot satisfy the requirements as a result of product inspection is regarded as a defective product and lowers the product yield.

For this reason, in the conventional powder spraying method,
Spraying has been performed with the spray nozzle sufficiently separated from the substrate so that the powder can be uniformly spread over a wide range.

However, this method has a problem that the apparatus becomes large and it takes a long time to spray the liquid crystal. This tendency becomes more and more remarkable in recent years when the size of the liquid crystal display panel is increasing. It is rare.

Accordingly, for example, Japanese Patent Application Laid-Open No.
No. 1 proposes that the spray area is enlarged by rotating the spray nozzle not in a fixed manner but in a circular shape.

[0009]

SUMMARY OF THE INVENTION The present invention not only achieves the same object as the above-mentioned proposal, but also achieves a reduction in the size of the spraying apparatus. In order to satisfy the demands of properties, etc., the amount of powder that is extremely expensive is reduced and the cost is reduced, and earnest research is conducted on methods that can simultaneously satisfy the purpose of effectively using resources. Stacked.

[0010]

The present invention described in each of the claims set forth above has been made to achieve the above object.

One of the features of the present invention is that, for example, a spray nozzle for spraying fine powder from above onto a substrate upper surface typically exemplified as a transparent substrate constituting a liquid crystal display panel, And a moving mechanism for relatively moving the substrate in each of the two horizontal x and y directions. The moving mechanism is configured to move the spray nozzle so that an extended line of the spray nozzle draws a zigzag scanning trajectory on the substrate. And a means for moving at least one of the spray nozzle and the substrate.

The moving mechanism for moving the spray nozzle and the substrate relative to each other is not particularly limited. For example, a cam mechanism is used to move the spray nozzle relative to the substrate in two horizontal x and y directions. In addition to a nozzle oscillating device for oscillating the nozzle, a first moving unit such as a conveyor for moving the substrate in the x direction and a second moving unit (for example, one Nozzle swing means for reciprocating the nozzle in the direction). According to the latter type of apparatus, it is possible to configure a continuous processing apparatus for spraying powder while continuously transporting a large number of substrates on a conveyor or the like.

The trajectory drawn by the extended line of the powder spraying nozzle in the form of a substrate in a “zigzag shape” means that, as shown in FIG. Drawing a trajectory of the nozzle extension line in a rectangle could be said to be ideal for uniform spraying and minimizing the amount of scattered powder, but in fact, a sawtooth-shaped zigzag trajectory was drawn. There is no great difference from the case, and the object of the present invention can be sufficiently achieved by the spray nozzle drawing the latter sawtooth-shaped trajectory, and the nozzle swinging mechanism can be simplified. In this case, the band-shaped powder spraying area provided with a certain width on both sides along the sawtooth-shaped trajectory is partially provided that the required range of the number of sprays per unit area is satisfied. Can be duplicated.

In order to reduce the amount of powder to be sprayed, it is desirable to limit the amount of powder to be sprayed in a range where the powder can be sprayed as necessary and sufficiently in the area to be sprayed (necessary) on the substrate.

According to the present invention, the distance between the substrate and the nozzle is set to 1 in a design specification satisfying the same level of spraying accuracy as compared with the conventionally proposed apparatus in which the spraying nozzle is rotated in a circular shape.
/ 2 or less.

Further, the area of the powder spraying area generated outside the area to be sprayed is greatly reduced, and from the comparison of the area ratios,
The amount of powder used can be reduced by several tens of percent.

The present invention is desirably used in combination with a powder supply apparatus (for example, an apparatus described in Japanese Patent Application No. 3-287879) capable of supplying finely divided powder as much as possible into primary particles.

According to such an apparatus, there is an advantage that the dispersion is sufficiently performed during (transportation) of the powder from the powder supply apparatus to the nozzle. That is, the powder supply device supplies a constant amount of powder to the flowing air, and the air containing the powder is transported at high speed through the narrow tube from the powder supply device to the nozzle. This is because dispersion is further promoted in the thin tube.

The powder dispersing device of the present invention can be used for various powder dispersing applications. In particular, powder as a spacer is interposed between substrates of an electro-optical element using liquid crystal. Excellently applied in applications.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in more detail with reference to the drawings.

Embodiment 1 FIGS. 1 to 4 are diagrams for explaining the present embodiment in which the present invention is applied to the manufacture of a liquid crystal display panel.
Reference numeral 1 denotes a container in which a space for dispersing powder is partitioned from the outside, and is provided at a lower portion in the container space by an opening / closing door (not shown) so that the substrate 2 to be dispersed can be installed and removed from the outside.

A spray nozzle 3 is provided substantially at the center of the upper part of the container, and a predetermined swing operation is performed by a swing mechanism 4 shown in FIG. The spray nozzle 3 is connected to a powder disperser 6 via a powder transport pipe 5, and ejects the dispersed powder from the nozzle 3 toward the lower substrate 2 by air pressure from a compressor 7. It has become.

As the powder feeder 6, it is preferable to use, for example, an air-mixing type powder dispersing and feeding apparatus described in Japanese Patent Application No. 3-287879, which is capable of precisely feeding a small amount of powder. Can be. In addition, the powder transport pipe 5
Is for transporting the powder for spraying from the powder supply air 6 to the nozzle 3, and the length / diameter ratio is set to 20.
It has been experimentally confirmed that the use of the above-mentioned material can favorably obtain a dispersion effect in the tube.

Reference numeral 8 denotes an exhaust pipe connected to a lower portion of the container 1, and the air in the container 1 is exhausted to the outside by a blower 9.

The swing mechanism 4 of the spray nozzle 3 will be described with reference to FIG. 2. In this embodiment, the spray nozzle 3 is supported by a ball bearing (not shown) at an intermediate position so that the spray nozzle 3 can swing freely. The upper end is rotatably connected to the end of the swing link 411, and the slider 413 provided with the pin 412 that forms the swing center of the swing link 411 is reciprocated in the direction of arrow B in the figure. The rotating circle at the upper end of the spraying nozzle 3 indicated by A in the figure follows the reciprocating movement of B.

Reference numeral 414 denotes a first motor provided on the slider 413.
11 is loosely fitted in the long hole 416 so as to be able to move in the longitudinal direction thereof, so that the swing link 411 swings around the pin 412, and thus the upper end of the spray nozzle is rotated in a circular manner. Reference numeral 417 denotes a second motor fixed to a device fixing portion (not shown), and a rotating piece 418 of the second motor 419 is oscillated around a pin 420 which is also fixed to the device fixing portion. The second swing link 419 is swung by loosely fitting into the hole 421, and the slider 413 is reciprocated in the B direction by engaging the protrusion 422 on the other end with the recess 423 provided in the slider 413. It is made to move.

By setting the rotation speed ratio of the first motor 414 and the second motor 417 and the magnitude of the swing of the swing links 411 and 419 in a predetermined relationship, the lower end of the spray nozzle 3 in FIG. (Powder ejection port) can be moved in a zigzag shape.

FIGS. 3 and 4 show a substrate 200 having a length of 300 mm (in a direction perpendicular to the plane of FIG. 1) and a width of 350 mm (in the horizontal direction in FIG. 1) using the powder dispersing apparatus having the above-described structure. In this example, the spray nozzle 3 is swung so as to draw a zigzag trajectory (trajectory of the nozzle extension line) shown by the line C in FIG. The spread angle of the powder ejected from the nozzle 3; 20 °; the swing angle in the B direction; 60 °; the distance from the substrate 2 to the lower end of the spray nozzle 3; 200 mm; Achieved.

At this time, the entire powder dispersion area (in the dotted line in FIG. 4) provided in a band along the zigzag trajectory C spreads slightly to the substrate surface where powder dispersion is required and the outside thereof. Was done. In addition, the powder dispersion area outside the substrate surface is indicated by hatching.

Comparative Example 1 Powder was sprayed in the same manner as in Example 1 except that the spray nozzle 3 was rotated circularly using the apparatus shown in FIG. The distance between the substrate 2 and the spray nozzle 3 was the same as in Example 1.

At this time, various angles of the cone apex angle drawn by the spray nozzle 3 were selected.

However, when the angle of the apex angle is set to, for example, 46 °, a circular trajectory on the substrate of the nozzle extension line shown by the line D in FIG. 6 and a scattered area shown by a dotted line along the nozzle trajectory can be understood. Thus, in the center of the circular locus and near the outer edge of the substrate 2,
The area where the powder was not sprayed was large.

Comparative Example 2 In the method of Comparative Example 1, while gradually increasing the distance between the substrate 2 and the spraying nozzle 3 until the powder on the entire surface of the substrate was uniformly dispersed as in Example 1, the spraying nozzle was Various angles of the cone apex angle described by No. 3 were selected.

As a result, the angle of the apex angle was 19 ° and the substrate 2
By setting the distance between the spray nozzle 3 and the spray nozzle 3 to 630 mm, a powder uniform dispersion state equivalent to that of the above-mentioned Example 1 could be achieved.

Assuming that the trajectory drawn by the extension line of the spraying nozzle in the shape of a substrate at this time is the E line, the outer edge of the powder spraying area is indicated by a broken line, and the area outside the substrate is hatched.

In this example, the state of powder spraying on the substrate could be made uniform as in Example 1, but the distance between the substrate and the spraying nozzle was about three times or more as compared with Example 1, and one sheet Spraying time on the substrate became longer. Further, as can be seen from the area ratios of the hatched portions in FIG. 4 and FIG.

[0037]

According to the powder spraying apparatus of the present invention, the distance between the substrate and the nozzle is reduced by half in a design specification capable of satisfying the same spraying accuracy as that of the apparatus in which the spray nozzle is rotated in a circular shape.
It has the effect of being able to reduce the height of the apparatus significantly, and also has the effect of greatly reducing the height of the apparatus.Because the flying distance of the powder is short, rapid processing becomes possible. In addition, there is an effect that the productivity can be improved by shortening the spraying time.

As is clear from the comparison between the above embodiment and the comparative example, the powder used is determined by the total area of the area to be sprayed and the area outside the area which does not normally need to be sprayed. In the present invention, the amount of powder used can be greatly reduced because the area outside the target area of powder spraying can be significantly reduced in the present invention, and the amount of powder used can be significantly reduced. The effect is obtained that the cost can be reduced by the reduction.

[Brief description of the drawings]

FIG. 1 is a diagram showing an overall schematic configuration of a powder spraying apparatus to which the present invention is applied;

FIG. 2 is a view showing an example of a cam mechanism for swinging a spray nozzle in the embodiment of FIG. 1;

FIG. 3 is a view for explaining a swinging state of a spray nozzle in Embodiment 1 of the present invention;

FIG. 4 is a diagram showing a scanning trajectory of a nozzle extension line drawn on a substrate by the movement of a cam mechanism of FIG. 3, and a powder dispersion area;

FIG. 5 is an explanatory view of Comparative Example 1 in which a spray nozzle is rotated in a circular shape;

FIG. 6 is a diagram showing a scanning locus of a nozzle extension line drawn on a substrate according to Comparative Example 1 of FIG. 5 and a powder spraying area;

FIG. 7 is an explanatory view of Comparative Example 2 in which a spray nozzle is rotated in a circular shape;

8 is a diagram showing a scanning trajectory of a nozzle extension line drawn on a substrate according to Comparative Example 2 of FIG. 7 and a powder spraying area,

FIG. 9 is a view for explaining a scanning trajectory of a spray nozzle extension line drawn on a substrate when ideal powder spraying is performed, and a powder spray area;

FIG. 10 is a view showing a mechanism for rotating a spray nozzle of Comparative Example 1 in a circular manner.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Container, 2 ... Substrate, 3 ... Spray nozzle, 4
... Swing mechanism, 5 ... Powder transport pipe.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G02F 1/1339 500 G09F 9/30 320

Claims (5)

(57) [Claims] 1. A spray nozzle for spraying a fine powder as a spacer for keeping a uniform gap between two transparent substrates from above on a substrate upper surface, and a spray nozzle and the substrate being horizontally biaxially spread. And a moving mechanism for relatively moving in the x and y directions, the moving mechanism comprising: a moving mechanism configured to move the spraying nozzle such that an extended line of the spraying nozzle draws a zigzag scanning trajectory on a substrate. A powder dispersing apparatus comprising: means for moving at least one of a nozzle and a substrate. 2. A spray nozzle according to claim 1, wherein said spray nozzle sprays fine powder from above the substrate upper surface , and a nozzle which swings said spray nozzle such that an extension of said spray nozzle draws a zigzag scanning trajectory on said substrate. A powder dispersing device comprising a swinging device. 3. The powder dispersion apparatus according to claim 1, wherein the substrate is a transparent substrate constituting an electro-optical element using liquid crystal. 4. A powder feeder having a length / diameter ratio of 20 or more, comprising: a powder supply device for continuously supplying a constant amount of powder to flowing air for powder dispersion; A powder spraying device connected via a pipe. 5. A powder dispersing nozzle for dispersing fine powder as a spacer on a substrate for keeping a uniform gap between two transparent substrates such that an extended line thereof draws a zigzag locus. A method for dispersing powder, characterized in that the powder is scanned.