JP2009064599A - Coating apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a coating apparatus that allows a smaller amount of liquid to adhere to a substrate even when liquid sucked up in the tip end of a liquid outlet portion is splashed, thereby reducing the possibility of improper coating. <P>SOLUTION: The coating apparatus for coating liquid on a target coating area of a substrate is provided with a shield mechanism that operates together with the liquid outlet portion 32 of the coating apparatus 1 and, when liquid discharged from the liquid outlet portion 32 is out of use, shields the splash of the liquid. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a coating apparatus that applies a liquid such as an organic EL material to a coating region on a substrate.

  An organic EL element is an element formed of an organic low-molecular or organic polymer having EL light-emitting ability in the light-emitting layer, and has a good viewing angle for self-emission and excellent impact resistance. have. For this reason, research and development are underway in various fields.

  As a manufacturing method, a vacuum deposition method, an ink jet method, a dispensing method, and the like are widely studied.

  In the dispensing method, patterning is generally performed by applying a liquid organic EL material to a stripe-shaped partition formed on a substrate while reciprocating a nozzle (liquid ejection unit) in parallel with the partition.

  As this type of coating apparatus, there is a coating apparatus described in Patent Document 1.

  However, in this type of apparatus, the organic EL material having a low viscosity is sucked up at the tip of the nozzle and scattered during operations other than the coating operation (for example, during alignment), resulting in a defective coating. It was.

  As a countermeasure of this type, as described in Patent Document 2, there is a method of preventing the organic EL material from being applied to an area that does not need to be applied by covering the area other than the application area with a mask.

JP 2001-189192 A JP 2004-5080 A

  However, in the method using the mask as in Patent Document 2, since the application region is not shielded by the mask, it is not possible to prevent unnecessary organic EL material from scattering in the application region. In order to actually apply with high accuracy, it is necessary to perform application after alignment of the substrate and to optimize misalignment and application amount. At this time, the nozzle reciprocates several times on the substrate after coating, and at this time, the organic EL material sucked up at the nozzle tip portion is scattered on the substrate, causing defective coating.

  An object of this invention is to provide the coating device which can reduce adhesion to a board | substrate even if the liquid sucked up by the nozzle tip part scatters, and can reduce application | coating defect.

As means for solving the above problems, the present invention provides:
In a coating apparatus that applies a liquid to a coating area on a substrate,
In conjunction with the liquid ejection part of the coating apparatus, a shielding mechanism is provided for shielding the scattering of the liquid when the liquid ejected from the liquid ejection part is unnecessary.

  The coating apparatus of the present invention can reduce adhesion to the substrate even when the liquid sucked up at the nozzle tip portion is scattered, and can reduce defective coating.

  Hereinafter, the coating apparatus of this invention is demonstrated using figures. Here, an organic EL material is taken as an example of the liquid to be applied and applied to the substrate of the organic EL element.

  1A and 1B are a plan view and a front view showing a schematic configuration of a coating apparatus according to the present invention.

  The illustrated coating apparatus 1 includes a substrate installation unit 2 and a coating mechanism 3.

  The substrate installation unit 2 includes a substrate stage 21 and a turning unit 22. A substrate such as an organic EL panel is set on the substrate stage 21 and the substrate stage 21 is rotated in the θ direction shown in the figure by the revolving unit 22 so that the substrate and the nozzle moving mechanism unit 31 are aligned in the horizontal direction. Yes.

  The coating mechanism 3 includes a nozzle moving mechanism unit 31, a nozzle (liquid ejection unit) 32, a nozzle holding unit 33, a shielding unit 34, a discharge unit 35, and an arm 36.

  The nozzle moving mechanism unit 31 is configured to be movable in the Y-axis direction, and a nozzle holding unit 33 is supported on the nozzle moving mechanism unit 31 so as to be movable in the X- and Z-axis directions. The nozzle 32 is supported by the nozzle holding unit 33, and the nozzle 32 is moved in the XYZ axial directions by the above-described configuration to apply the organic EL material to a desired position on the substrate.

  In the present invention, only one nozzle 32 is shown for simplicity of explanation, but a plurality of nozzles may be used when red, green, and blue organic EL materials are applied. In the present invention, the nozzle 32 is moved in the X, Y, and Z axis directions. However, as a coating method, the substrate may be moved, or both may be moved.

  As described above, in the coating apparatus of the present invention, after the horizontal alignment between the substrate and the nozzle moving mechanism unit 31 is performed by the swivel unit 22, the nozzle 32 is moved in the XYZ axial directions, thereby the desired position of the substrate. An organic EL material is continuously applied to the substrate and patterned. However, as described above, the nozzle 32 reciprocates several times on the substrate after the coating operation, and at this time, the organic EL material sucked up at the tip portion of the nozzle 32 is scattered on the substrate, causing the coating failure. It becomes.

  Therefore, the present invention is characterized by including a shielding mechanism that shields scattering of the organic EL material ejected from the nozzle 32 when it is not necessary, that is, during operations other than the coating operation.

  As shown in FIGS. 2A and 2B, the shielding mechanism is scattered by temporarily inserting the shielding portion 34 by the arm 36 through the nozzle holding unit 33 at the tip portion (lower end portion) of the nozzle 32. The organic EL material is prevented from being applied to the substrate. Specifically, one end portion of the arm 36 is rotatably connected to the nozzle holding unit 33, and a shielding portion 34 is provided at the other end portion. For example, when an organic EL material application operation end signal is received, the arm 36 is rotated by a rotation mechanism provided in the nozzle holding unit 33 so as to be interlocked with the end of the nozzle 32 application operation. And the shielding part 34 is moved so that it may enter between the nozzle 32 and a board | substrate, and it arrange | positions in the position directly under the said nozzle 32 (refer Fig.2 (a)). On the other hand, upon receiving a signal for starting the application operation of the organic EL material, the arm 36 is rotated by a rotation mechanism provided in the nozzle holding unit 33 so as to be interlocked with the start of the application operation of the nozzle 32. Then, the shielding part 34 is retracted so as not to enter between the nozzle 32 and the substrate (see FIG. 2B). Therefore, even if the organic EL material sucked up at the tip portion of the nozzle 32 is scattered, the adhesion to the substrate can be reduced. Further, when performing the coating operation, the coating operation can be performed without affecting the coating operation by retracting the shielding portion 34 so as not to enter between the nozzle 32 and the substrate.

  Incidentally, the shielding portion 34 is not particularly limited as long as it can catch the scattered organic EL material, but it is preferably a funnel shape as shown in the figure, and is discharged to an opening formed at the lower end portion thereof. It is preferable that the part 35 is provided. The discharge unit 35 operates in conjunction with a discharge unit (not shown) and discharges the organic EL material accumulated in the shielding unit 34. By discharging the scattered organic EL material at any time, it is possible to prevent the organic EL material from accumulating on the shielding part 34 even during mass production, and to enable continuous application stably over a long period of time.

  Hereinafter, a comparative example of the coating result using the present invention and the coating result of the conventional method will be described. FIG. 3 is a schematic view of a substrate for an organic EL element used in the present invention. A patterned pixel electrode 102 and a TFT circuit (not shown) were formed in the display area on the glass substrate 101, and an extraction electrode (not shown) was formed outside the display area.

  Further, a bank 103 made of a photosensitive polyimide material was formed by photolithography.

  The height of the bank 103 was 3 μm, and the width of the bank 103 and the width between the banks were 30 μm and 200 μm, respectively. The number of stripe-shaped pixel lines sandwiched between the banks 103 is 100.

  Next, UV ozone treatment was performed for 10 minutes in order to remove residual organic substances during the formation of the bank 103.

Next, liquid repellency was imparted to the bank 103 by performing fluorine plasma treatment with CF ₄ gas.

  PEDOT / PSS is continuously applied as a hole injection material between the stripe-shaped banks 103 using the coating apparatus 1 of the present invention, and baked on a hot plate at 200 ° C. for 30 minutes to form a hole injection layer having a thickness of 30 nm. Formed.

  Next, similarly, a solution in which 1 wt% of polyparaphenylene vinylene derivative poly [2-methoxy, 5- (2′-ethylhexoxy) -1,4-phenylene vinylene] was dissolved in tetralin was applied between the banks 103. After the application, an organic EL layer having a film thickness of 100 nm was formed by baking at 150 ° C. for 10 minutes on a hot plate.

  During this time, during the operation other than the application operation, application was performed by setting the shielding portion 34 of the present invention so as to be inserted immediately below the nozzle 32.

Thereafter, Cs ₂ CO ₃ was deposited to a thickness of 3 nm as an electron injection layer using a vacuum deposition apparatus, and Al was deposited to a thickness of 150 nm as an upper electrode.

  The organic EL element was produced by moving from vacuum to nitrogen and adhering a glass cap provided with a hygroscopic agent so as to cover the pixel portion.

<Comparative example>
On the other hand, as a comparative example, an organic EL element was formed by applying an organic EL material to a substrate similar to the example under the same conditions without using the shielding mechanism of the coating apparatus 1 of the present invention.

<Evaluation>
Of the 100 organic EL elements in the prepared example and the organic EL element in the comparative example, the ratio of coating defects due to scattering of the organic EL material was compared. Table 1 shows the defect rate in the example and the defect rate in the comparative example.

  As shown in Table 1, the organic EL elements of the examples prepared using the coating apparatus of the present invention were able to greatly reduce coating defects.

  In the present invention, a low-viscosity organic EL material is used as the liquid to be scattered, and coating is performed on the substrate of the organic EL element. However, the present invention improves the liquid scattering and is particularly effective as long as the same effect can be obtained. It is not limited to this field.

It is a schematic block diagram of the coating device in this invention. It is a schematic diagram of the nozzle front-end | tip part in the coating device of FIG. It is an organic EL element substrate.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Application | coating apparatus 2 Substrate installation part 21 Substrate stage 22 Turning part 3 Application | coating mechanism 31 Nozzle movement mechanism part 32 Nozzle (liquid discharge part)
33 Nozzle holding unit 34 Shielding portion 35 Discharging portion 36 Arm 101 Substrate 102 Pixel electrode 103 Bank

Claims (4)

In a coating apparatus that applies a liquid to a coating area on a substrate,
A coating apparatus, comprising: a shielding mechanism that interlocks with a liquid ejection unit of the coating apparatus and shields the scattering of the liquid when the liquid ejected from the liquid ejection unit is unnecessary.   The shielding mechanism includes a shielding part, and when performing the liquid application operation, the shielding part is retracted so as not to enter between the liquid discharge part and the substrate, and performs the liquid application operation. 2. The coating apparatus according to claim 1, wherein when there is not, the coating apparatus is configured to move so as to enter between the liquid ejection unit and the substrate.   The coating apparatus according to claim 1, wherein the shielding portion is provided with a discharge portion that discharges the liquid accumulated in the shielding portion.   The coating apparatus according to claim 1, wherein the liquid is made of an organic EL material.

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