JP2013208520A - Coating nozzle, coating method using the same, and method of manufacturing member for display - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coating nozzle formed with a plurality of ejection holes, preventing cleanability from being deteriorated by taking erosion suppression measures such as a reduction in ultrasonic output and a change of a cleaning solvent in ultrasonic cleaning, and preventing the ejection holes from being damaged by erosion.SOLUTION: A coating nozzle 21 includes: a plurality of ejection holes 26 for ejecting paste formed in a substantially linear row, wherein the coating nozzle has a plurality of uneven portions formed of recessed portions 27 and/or protrusions, the uneven portions are formed in such a manner as to be orthogonal to a row formed of the ejection holes, on a nozzle surface where the plurality of ejection holes are formed, and to form a row almost parallel to the row formed of the ejection holes, within an area held between two straight lines passing through the ejection holes positioned at both ends of the row, and the row formed of the uneven portions comprises the number of uneven portions, equivalent to 90% or more of the number of ejection holes.

Description

  The present invention relates to a coating nozzle that eliminates ultrasonic damage during ultrasonic cleaning, a coating method that uses a coating nozzle that has been cleaned by ultrasonic cleaning, and a plasma display that manufactures a member for a plasma display by the coating method. The present invention relates to a method for manufacturing a member.

  One of the displays attracting attention among various displays diversified by various methods is a large-sized PDP that can be reduced in thickness and weight. The PDP generates a discharge in a discharge space formed between the front plate and the back plate, and the discharge generates ultraviolet rays centering on a wavelength of 147 nm from the xenon gas, and the ultraviolet rays excite the phosphor to cause display. It becomes possible. Full-color display can be supported by causing the driving circuit to emit light by separately emitting discharge cells in which phosphors emitting red (R), green (G), and blue (B) are separately applied.

  A typical AC plasma display in this PDP includes a front glass plate on which display electrodes / dielectric layers / protective layers are formed, and a rear glass plate on which address electrodes / dielectric layers / partition layers / phosphor layers are formed. It has a structure in which a mixed gas of He—Xe or Ne—Xe is sealed in a discharge space partitioned and bonded by stripe-shaped or grid-shaped barrier ribs. Each of the phosphor layers of R, G, and B includes a phosphor having powdery phosphor particles as a main component, a partition extending in one direction for each color formed on the back plate, or such a partition and It is filled with fine grooves formed by orthogonal auxiliary partition walls. For the phosphor layer, a phosphor paste containing phosphor powder, an organic binder and an organic solvent as main components is applied to the above-mentioned partition walls, or fine grooves formed by the partition walls and the auxiliary partition walls, dried, and fired as necessary. It is formed by doing. In order to manufacture a product having such a structure with high productivity and high quality, a coating technique for coating the phosphor paste in a certain pattern is important (Patent Document 1).

  The coating nozzle for applying a coating liquid such as a phosphor paste used in manufacturing such a PDP or the like discharges the paste toward a minute groove formed on a substrate such as a PDP back plate. Fine discharge holes corresponding to the size of the pixels are regularly formed from several tens to several thousand according to the number of pixels and the coating method.

  This coating nozzle removes or coats clogged foreign matter when gelled coating liquid, agglomerated phosphor particles, and foreign matter in the coating liquid become clogged with discharge holes and become difficult to use. In order to prevent mixing of the coating liquid when changing the coating liquid, it is necessary to prepare for reuse by precisely cleaning the surface of the coating nozzle including the inner surface of the fine discharge holes.

  Ultrasonic cleaning is applied to the precision cleaning of the coating nozzle because of its high cleaning performance. The ultrasonic cleaning of the coating nozzle is performed by immersing the coating nozzle in the cleaning liquid filled in the cleaning tank, and on the surface of the coating nozzle, the ejection surface, which is a plane on which ejection holes are formed, and the vibration surface of the ultrasonic transducer Are faced in parallel at regular intervals, and the ultrasonic wave irradiated from the ultrasonic transducer is allowed to act on the ejection holes and the nozzle surface.

  This is because when the ultrasonic wave irradiated from the vibration surface of the ultrasonic transducer is transmitted to the nozzle surface such as the discharge surface of the coating nozzle through the cleaning liquid, cavitation occurs in the vicinity of the surface, and the bubbles break up and disappear in this cavitation. The impact force generated at the time is transmitted to the surface of the coating nozzle including the inner surface of the fine discharge hole, and the dirt composed of dried phosphor paste, phosphor particle aggregates, foreign matters, etc. adhering to those surfaces is scraped off. Because. In particular, in the case of a high-viscosity paste of 10 Pa · s or more, the adhesive force to the coating nozzle is strong, so it is necessary to perform ultrasonic cleaning at a relatively low frequency (50 kHz or less) with strong cavitation.

  On the other hand, however, there is a problem that erosion (erosion), which is a phenomenon that wears and damages the surface of the object to be cleaned, occurs on the surface where the cleaning liquid contacts the coating nozzle due to the impact force of the cavitation. In the ultrasonic cleaning, erosion is likely to occur. In application nozzles with many fine discharge holes, cavitation tends to concentrate on the discharge holes and their surroundings, and repeated ultrasonic cleaning damages the edges of the discharge holes and causes deformation of the discharge holes. Therefore, the phosphor paste cannot be accurately applied in a certain pattern. For this reason, there has been a problem that the coating nozzle has to be discarded and a new coating nozzle must be manufactured and purchased with a service life that is significantly shorter than originally planned.

  As a method for suppressing this erosion, a method of decreasing the output of the ultrasonic wave or increasing the frequency of the ultrasonic wave to weaken cavitation is known. However, according to these methods, there is a problem that an impact force due to cavitation is weakened and a cleaning failure occurs due to a reduction in cleaning power. In addition, it is conceivable to change the coating nozzle to a high-hardness material in order to improve the resistance to erosion, but it is difficult to process a large number of fine discharge holes, and the cost of the material is large. In addition, there is a concern that the corrosion resistance to the coating liquid may be reduced, so that it is not suitable for use as a coating nozzle member.

  Further, as disclosed in Patent Document 2, there is a method in which the cleaning solvent is an alkaline aqueous cleaning liquid and the surface of the object to be cleaned is passivated to suppress erosion. However, a pattern coating coating liquid such as a phosphor paste is generally a binder component. In some cases, a water-insoluble component may be included. In such a case, it is necessary to perform cleaning with an organic solvent, so that it is difficult to apply an aqueous cleaning solution. Furthermore, since the phosphor paste contains very hard fine particles at a high concentration, it acts on the nozzle surface as if it were abrasive particles during the coating process or during cleaning, causing the passive layer or coating layer on the surface to peel or wear away. So it is difficult to apply.

  In addition, it has been proposed to diffuse the impact force generated when bubbles break up and disappear in cavitation by forming fine undulations on the surface where ultrasonic erosion occurs (Patent Document 3). When undulations are formed on the surface, the edges of the discharge holes become jagged and rough, which makes it impossible to accurately apply the phosphor paste in a certain pattern, making it difficult to apply to the application nozzle.

JP 2004-000928 A JP 2002-12990 A JP 2005-335416 A

  The present invention has been made in view of the above, and is a coating nozzle in which a plurality of discharge holes are formed, and measures for suppressing erosion such as reduction of ultrasonic output and change of cleaning solvent in ultrasonic cleaning are provided. An object of the present invention is to provide a coating nozzle that does not deteriorate the cleaning performance and does not damage the discharge holes due to erosion.

  In order to achieve the above object, the present invention provides an application nozzle in which a plurality of discharge holes for discharging a paste are formed in a substantially straight line, and the application nozzle has a hollow shape. And / or a plurality of projections and depressions, and the projections and depressions are orthogonal to the rows formed by the ejection holes on the nozzle surface on which the plurality of ejection holes are formed, and at both ends of the rows. In a region sandwiched between two straight lines that pass through the discharge holes that are positioned, the rows that are formed to form rows substantially parallel to the rows that the discharge holes form, and the rows formed by the concavo-convex portions, There is provided a coating nozzle characterized by comprising a number of uneven portions of 90% or more of the number.

  Further, it is preferable that a plurality of rows formed by the uneven portions are formed, and one or more rows are arranged on both sides of the row formed by the discharge holes.

  Furthermore, it is preferable that an interval between the uneven portions forming a row is equal to or less than a maximum interval of the discharge holes forming the row.

  The present invention provides a method for applying a paste, which comprises applying the paste by discharging the paste onto a substrate using the ultrasonically cleaned application nozzle.

  Moreover, the manufacturing method of the member for plasma displays characterized by apply | coating fluorescent substance paste using the application | coating method of said paste is provided.

  In the present invention, the concavo-convex portion is a dent portion (concave portion) or a projection portion (convex portion), and the concave and convex portions may be mixed in a substantially straight line.

  In the present invention, the coating nozzle, which has conventionally been damaged by erosion and has shortened the service life due to erosion, is concentrated in the ejection hole by using the coating nozzle having the uneven portion of the present invention. Cavitation can be dispersed or selectively generated at a position that does not hinder the function of the coating nozzle, and erosion control measures such as reducing ultrasonic output and changing the cleaning solvent are taken to reduce cleaning performance. Without damaging the discharge holes due to erosion, an application nozzle can be obtained that can easily maintain the quality of the pattern application result before and after ultrasonic cleaning. This also makes it possible to obtain a coating nozzle that can achieve the service life inherent to the nozzle, and to reduce the manufacturing cost of final products such as image display devices.

  In addition, by forming a plurality of rows of uneven portions of the coating nozzle and arranging one or more on each side of the row of ejection holes, cavitation that has occurred more reliably in the ejection holes Can be selectively generated at positions that do not interfere with the function of the coating nozzle.

  Furthermore, since the interval between the uneven portions forming the row of the application nozzles is equal to or less than the maximum interval of the discharge holes forming the row, it is possible to more reliably prevent cavitation from being concentrated on the discharge holes.

  By applying the application nozzle in the present invention to the application of the paste to the substrate, the paste can be applied accurately in a certain pattern. In particular, by applying the coating nozzle in the present invention to phosphor paste coating on a plasma display substrate, a member for plasma display without coating defects can be produced.

It is the schematic diagram which showed an example of the application | coating apparatus of the coating liquid using the cross-sectional shape of the array direction of the discharge hole of the coating nozzle unit comprised by the coating nozzle and manifold which concerns on this invention, and the coating nozzle unit. It is a schematic diagram of the discharge surface of the coating nozzle shown in FIG. It is the photograph of the aspect after ultrasonic cleaning by the pure water of the discharge surface of the application nozzle shown in FIG. It is a schematic diagram of the discharge surface of the coating nozzle by the prior art shown in the comparative example 1. It is a photograph of the aspect after ultrasonic cleaning by the pure water of the discharge surface of the application nozzle shown in FIG. It is a schematic diagram of the discharge surface of another application nozzle according to the present invention shown in Example 1. It is the photograph of the aspect after ultrasonic cleaning by the pure water of the discharge surface of the application nozzle shown in FIG. 6 is a schematic diagram of a discharge surface of a coating nozzle shown in Comparative Example 2. FIG. It is a photograph of the aspect after the ultrasonic cleaning by the pure water of the discharge surface of the application nozzle shown in FIG.

  Hereinafter, the case where the preferred embodiment of the present invention is applied to an application nozzle for applying a phosphor paste for PDP will be described with reference to the drawings. The application nozzle of the present invention is an application nozzle for paste. There is no limitation to the coating nozzle for the phosphor paste for PDP.

  First, a coating liquid coating apparatus using a coating nozzle unit including a coating nozzle and a manifold according to an embodiment of the present invention, particularly a substrate having a fine groove formed by a partition wall and a partition wall and an auxiliary partition wall (for example, An example of an apparatus for applying a coating liquid onto a plasma display panel member) will be described. FIG. 1 shows a configuration of a portion related to replenishment and discharge of a coating liquid in a coating apparatus using a coating nozzle unit according to an embodiment of the present invention, and an arrangement direction of a plurality of discharge holes forming a substantially straight line. It is the schematic diagram which showed the cross-sectional shape of the coating nozzle unit.

  First, a portion related to replenishment of the coating liquid to the coating nozzle unit 20 including the coating nozzle 21 and the manifold 22 in the coating apparatus 1 shown in FIG. 1 will be described. A pipe 4 for replenishing the coating liquid in the liquid storage section 24 is connected to the replenishing port 23 in the coating nozzle unit 20, and the opposite end of the pipe 4 has an opening / closing valve 5 that controls the replenishment of the coating liquid. The coating liquid container 3 which stores a coating liquid is connected through this. The opening / closing valve 5 is controlled to be opened and closed by the controller 12. A pipe 7 for supplying a control gas for extruding the coating liquid and replenishing the coating nozzle unit 20 is connected to the coating liquid container 3, and a pressure reducing valve 8 is connected to the opposite side of the pipe 7. It is connected to a gas source 6 for discharge control. The pressure reducing valve 8 can adjust the control gas of the discharge control gas source 6 to a pressure necessary for replenishing the coating liquid.

  Next, the part which concerns on discharge of the coating liquid from the coating nozzle unit 20 is demonstrated. A pipe 9 serving as a passage for supplying and discharging control gas is connected to the liquid storage section 24 of the coating nozzle unit 20, and a discharge valve 10 is connected to the opposite side of the pipe 9. The discharge valve 10 is a three-way valve, one of which is connected to a discharge control gas source 6 via a pressure reducing valve 11 and the other is open to the atmosphere. The pressure reducing valve 11 can adjust the control gas of the discharge control gas source 6 to a pressure necessary for discharging the coating liquid from the coating nozzle unit 20. The discharge valve 10 can switch whether the liquid storage part 24 of the application nozzle unit 20 communicates with the discharge control gas source 6 or the atmosphere, and the switching is controlled by the controller 12.

  In the coating apparatus 1 shown in FIG. 1, when performing coating, first, the coating liquid is supplied from the coating liquid container 3 into the liquid storage section 24 of the coating nozzle unit 20. The replenishment of the coating liquid to the coating nozzle unit 20 is performed by opening the opening / closing valve 5, and after the replenishment is completed, the opening / closing valve 5 is closed.

  At this time, the coating liquid is stored in a predetermined amount in the liquid storage section 24 of the coating nozzle unit 20 so as to leave a space 25. The amount of the coating liquid in the liquid storage unit 24 is set so that the time until the space 25 in the liquid storage unit 24 is filled with the control gas and the coating liquid is discharged from the discharge hole 26 for each discharge is made uniform. It is necessary to keep it constant. Therefore, after discharging the coating liquid, the coating liquid is always supplied into the liquid storage section 24 until the volume of the space portion 25 reaches a predetermined amount. Therefore, it is preferable to have a coating liquid amount detecting means (not shown) for detecting the coating liquid amount in the liquid storage section 24.

  The discharge of the coating liquid from the coating nozzle unit 20 is performed by switching the discharge valve 10 so that the coating nozzle unit 20 and the discharge control gas source 6 communicate with each other, into the space 25 in the liquid storage section 24 of the coating nozzle unit 20. This is done by extruding the coating liquid from the discharge hole 26 by supplying a control gas. Further, the discharge of the coating liquid from the coating nozzle unit 20 is stopped by switching the discharge valve 10 so that the space portion 25 is opened to the atmosphere, thereby stopping the supply of the control gas. This is done by discharging the control gas.

  In addition, the replenishment of the coating liquid to the coating nozzle unit 20 and the control of the discharge of the coating liquid from the discharge hole 26 are connected to the coating liquid amount detection means, the opening / closing valve 5 and the discharge valve 10 in the liquid storage section 24. It is controlled by the controller 12.

  Here, the material of the application nozzle may be any material such as alloy steel such as chrome steel, nickel steel, and stainless steel, and non-ferrous metal such as carbon steel, aluminum, copper, and alloys thereof. However, when a foreign substance such as rust is mixed in a coating liquid such as a phosphor paste, it may cause clogging of fine discharge holes. However, the material is not limited to this as long as the function as the application nozzle is not impaired, and various known materials can be used.

  There are no particular restrictions on the dimensions of the coating nozzle, but the length is such that the phosphor paste of at least one color can be applied to the entire surface of the glass substrate in a single coating operation (about 42 inches for a glass substrate for a PDP). 1 m or more) is preferable. In particular, it is more suitable for coating a large PDP phosphor of 30 inches or more. The length of the application nozzle refers to the distance from end to end of the application nozzle in the arrangement direction of a plurality of discharge holes that form a substantially straight line.

  As a method for processing the discharge hole, a known processing method such as electric discharge processing, laser processing, or drilling can be appropriately selected according to the nozzle material and the shape of the discharge hole.

  Next, FIG. 2 is a schematic plan view showing a discharge surface, which is a plane on which the discharge holes 26 are formed on the nozzle surface, for the application nozzle 21 in the application nozzle unit 20 shown in FIG.

  In the application nozzle 21 shown in FIG. 2, a plurality of discharge holes 26 for discharging the phosphor paste form a substantially straight line 201, and the intervals (pitch) between the discharge holes 26 are all equal. ing. Here, the number and arrangement of the discharge holes may be selected according to the substrate to be applied and the application method. For example, a phosphor paste containing phosphor powder of any of R, G, and B is applied to a substrate having a fine groove like the back plate of the plasma display shown in FIG. 1 in one application operation. In this case, the ejection holes are formed in a substantially straight line with the number and pitch corresponding to the fine groove portions of the substrate to be coated. However, the number of ejection holes is reduced to one substrate by a plurality of coating operations. As long as the coating is completed, the pitch may be widened, or all pitches may be formed at unequal pitches.

  Further, the size and shape of the discharge hole of the coating nozzle may be selected according to the width of the coating liquid to be applied and the amount of the coating liquid to be applied, and is not particularly limited. There may be.

  In the coating nozzle 21 shown in FIG. 2, the surface on which the discharge holes are formed is a plane for convenience of processing of the coating nozzle, but it may be a curved surface, and is not particularly limited thereto.

  A plurality of depressions 27 are formed on the discharge surface of the application nozzle 21 shown in FIG. 2 where the discharge holes 26 are formed. The recess 27 is formed to form the discharge holes 26 that form a substantially straight line 201 and the parallel lines 202, 203, 204, and 205 on the discharge surface, and sandwich the line 201 of the discharge holes 26. In addition, a total of four rows, two rows on each side, are provided. The hollow portion 27 induces cavitation to disperse the cavitation that has been concentrated only on the discharge hole 26 until now, or the cavitation portion 27 and its surrounding positions that do not hinder the function of the coating nozzle 21. As a result, damage to the discharge holes 26 due to erosion can be suppressed.

  Here, it is preferable that the shape of the hollow portion is circular on the discharge surface, and the diameter thereof is 25 μm or more and 500 μm or less. When the hollow portion is out of this range, the effect of the hollow portion is lost, and erosion occurs in the discharge hole. More preferably, they are 50 micrometers or more and 300 micrometers or less. The depth of the recess is preferably 25 μm or more with reference to the discharge surface having the discharge holes. If this value is less than 25 μm, erosion occurs in the ejection holes as in the case where no dummy exists.

  In the coating nozzle 21 shown in FIG. 2, there are four rows 202, 203, 204, 205 formed by the depressions 27, two rows on each side so as to sandwich the row 201 formed by the discharge holes 26. There may be only one row, preferably one or more rows are arranged on both sides so as to sandwich the row formed by the discharge holes, more preferably two or more rows on one side. Even if the row formed by the depressions is one row on one side parallel to the row formed by the discharge holes, the effect of dispersing the cavitation in which the discharge holes are concentrated can be obtained, but one or more depressions are formed on both sides of the row formed by the discharge holes. If the rows are arranged, the effect of cavitation dispersion is further enhanced, and damage due to erosion of the discharge holes can be reliably prevented.

  Further, the rows 202, 203, 204, and 205 formed by the depressions 27 in the coating nozzle of FIG. 2 are orthogonal to the row 201 formed by the discharge holes 26 on the discharge surface, and the discharge holes positioned at both ends of the row 201. The same number of depressions 27 as the discharge holes 26 are provided in the region A (the region indicated by the hatched portion) sandwiched between the two passing straight lines. The larger the number of depressions, the higher the effect of cavitation dispersion. However, if the number is 90% or more of the number of ejection holes, the effect can be obtained. In addition, three depressions are formed on both sides on each row outside the region, but it is preferable that there are three or more depressions in order to avoid concentration of cavitation in the discharge holes at the end of the row.

  In the application nozzle 21 of FIG. 2, the mutual interval (pitch) of the depressions 27 in the rows 202, 203, 204, 205 formed by the depressions 27 is the same as the pitch of the ejection holes 26. If the pitch of the recesses is equal to or less than the pitch of the discharge holes, a cavitation dispersion effect can be obtained. However, if the pitch of the recesses is larger than the pitch of the discharge holes, there may occur discharge holes in which the cavitation is not sufficiently dispersed. Is preferably equal to or less than the pitch of the discharge holes.

  Moreover, it is preferable that the position which provides the row | line | column which a hollow part forms is the range whose distance with the row | line | column which a discharge hole comprises is 5000 micrometers or less. If it exceeds 5000 μm, the effect of dispersing cavitation due to the indented portion is lost, and erosion due to cavitation may occur in the discharge hole. More preferably, the distance between the row formed by the depressions closest to the ejection holes and the row formed by the ejection holes is preferably in the range of 3000 μm or less.

  It should be noted that the dent portion is not necessarily a dent portion (concave portion) as long as cavitation can be induced, and may be a projection portion (convex portion) or a combination of the dent portion and the projection portion.

  For example, the recess may be formed by cutting with a drill or a reamer, or may be forged using a die or a punch. The material of the application nozzle and the shape of the recess are not limited to these. Various processing methods can be used. Moreover, about a projection part, you may affix and install a protrusion-shaped thing, The formation method is not specifically limited.

  Here, the frequency range of the ultrasonic wave used for cleaning the coating nozzle is preferably 5 kHz or more and 100 kHz or less, and the ultrasonic intensity is 0.5 W / cm 2 or more. Outside this range, the strength of ultrasonic cavitation is reduced, and the cleaning ability is not sufficient, which is not preferable.

  Various known cleaning liquids can be used depending on the coating liquid to be cleaned and the material of the coating nozzle. Particularly in the case of a phosphor paste mainly composed of phosphor powder, an organic solvent, and an organic binder (resin component), a cleaning solvent (usually an organic solvent) that can dissolve the organic solvent and the resin component is used. good. Such organic solvents are appropriately selected from various solvents such as acetone, ethanol, diacetone alcohol, IPA (isopropyl alcohol), MEK (methyl ethyl ketone), fluorine-based solvents, various non-hazardous solvents (for example, trade name Elise: Asahi Kasei). can do. Further, when such cleaning is performed over several stages, the cleaning effect is further enhanced. For example, diacetone alcohol cleaning as the primary cleaning, acetone cleaning as the secondary cleaning, pure water cleaning as the final cleaning, etc. can be performed as the first cleaning. Increase it.

  The coating nozzle of the present invention requires ultrasonic cleaning in order to continue pattern coating of a highly viscous coating liquid, and is suitable as a coating nozzle capable of pattern coating a paste having a viscosity of 1 Pa · s or more. However, when a high-viscosity paste having a viscosity in the range of 1 to 1000 Pa · s or a high-viscosity paste having a viscosity in the range of 10 to 100 Pa · s is used for a coating nozzle, Even if this application nozzle is ultrasonically cleaned without deliberately reducing the ultrasonic output, it is extremely effective in that accurate pattern application can be continued without the edges of the discharge holes being cut before and after this cleaning. preferable. A typical example of the high-viscosity paste is a phosphor paste application nozzle that applies a phosphor paste for plasma television production.

Example 1
An example in which the coating nozzle according to one embodiment of the present invention is ultrasonically cleaned and the coating liquid is further applied to the plasma display back plate using the coating nozzle will be described.

  The coating nozzle 21 shown in FIGS. 1 and 2 was prepared. The discharge holes 26 are circular having a diameter of 80 μm, and 1921 holes are formed on a stainless steel plate (SUS304) having a width of 100 mm, a length of 1000 mm, and a thickness of 0.5 mm substantially at a pitch of 0.48 mm. The application nozzle 21 has four recesses 27, 203, 204, 205 in parallel with the row 201 so as to sandwich the discharge holes 26 forming the row 201 in a substantially straight line. A row is formed, and there are 1927 depressions 27 forming each row 202, 203, 204, 205. The depressions 27 have a shape with a diameter of 100 μm and a depth of 100 μm, and the pitch of the depressions 27 in each row 202, 203, 204, 205 is the same as that of the ejection holes 26 and is 0.48 mm. Further, the distance between the row 201 formed by the discharge holes 26 and the rows 202, 203, 204, and 205 formed by the depressions 27 is 1500 μm in the rows 202 and 203 on the side closer to the rows formed by the discharge holes, and the rows on the far side. 204 and 205 are 2500 μm.

  First, a black oil-based paint is applied to the discharge surface of the application nozzle 21 and then put into a cleaning tank containing pure water, and an ultrasonic wave having an ultrasonic intensity of 1.0 W / cm 2 and a frequency of 25 kHz is irradiated for 15 minutes. Ultrasonic cleaning was performed. In FIG. 3, the photograph of the aspect of the discharge surface of the coating nozzle 21 after ultrasonic cleaning is shown. In this aspect of the discharge surface, the black portion indicates that the oil paint remains, and the white portion indicates that the oil paint is removed and the stainless steel surface is exposed. As shown in FIG. 3, it was confirmed that the coating nozzle 21 had most of the oil-based paint removed in the recess 27 and its periphery, and erosion due to cavitation was not concentrated in the discharge hole 26 and its periphery.

  Then, next, this application nozzle 21 is put into a washing tank containing diacetone alcohol, and after applying ultrasonic waves with an ultrasonic intensity of 1.0 W / cm 2 and a frequency of 25 kHz for 1 hour, pure water is applied to the application nozzle. It replaced with the washing tank which entered, and ultrasonic cleaning which irradiates the ultrasonic wave with the ultrasonic intensity of 1.0 W / cm <2> and the frequency of 25 kHz for 1 hour was repeatedly performed 10 times. After the ultrasonic cleaning was completed, the discharge surface of the coating nozzle 21 was observed with a microscope. However, the discharge hole 26 was not damaged and it was confirmed that no erosion occurred.

  Furthermore, the application nozzle unit 20 was assembled by fastening the application nozzle 21 and the manifold 22 with bolts, and the phosphor paste was applied to the plasma display back plate as a substrate. The substrate has 5964 ribs with a size of 990 × 600 mm, a height of 0.12 mm and a top width of 0.04 mm on the surface to be coated, and a pitch of 0.16 mm. The width was 0.12 mm, and the number of grooves was 5762. The coating liquid used was a phosphor paste containing a green phosphor powder having a viscosity of 50 Pa · s.

  A coating liquid coating apparatus 1 shown in FIG. 1 was used as a coating apparatus for coating the phosphor paste between the partition walls of the substrate. The coating apparatus 1 is installed in an environment where the air temperature is kept constant at 23 ° C.

  A gas for control adjusted to a pressure of 0.35 MPa by the pressure reducing valve 8 is applied to the coating liquid container 3. The opening / closing valve 5 for controlling the replenishment of the coating liquid from the coating liquid container 3 to the coating nozzle unit 20 is a diaphragm valve.

  The phosphor paste in the liquid storage part 24 of the coating nozzle unit 20 is managed so that the liquid level is 25 mm from the discharge hole 26. Therefore, after the phosphor paste is discharged from the application nozzle unit 20, the phosphor paste is supplied to the application nozzle unit 20 until the liquid level becomes 25 mm by controlling the opening / closing of the opening / closing valve 5.

  The pressure applied to the coating nozzle unit 20 to discharge the phosphor paste as the coating liquid was set to a pressure of 0.80 MPa by the pressure reducing valve 11.

  Under the above-described conditions, the coating apparatus 1 shown in FIG. 1 using the coating nozzle unit 20 including the coating nozzle 21 shown in FIG.

  When the substrate coated with the phosphor was dried, a substrate having a phosphor layer formed in the groove portion formed by the partition walls was obtained. When the phosphor layer is irradiated with an ultraviolet lamp having a wavelength of 254 nm to cause the phosphor layer to emit light and the light emission state is visually confirmed, light is emitted uniformly over the entire surface of the substrate, resulting in poor coating. Confirmed that there is no.

Comparative Example 1
Next, the coating nozzle 31 in the prior art shown in FIG. 4 was prepared. The outer shape, material, shape, number, and pitch of the application nozzle 31 are the same as those of the application nozzle used in Example 1. The application nozzle 31 is not formed with a recess, and only the discharge hole 36 is formed on the discharge surface.

  FIG. 5 shows a photograph of the appearance of the discharge surface of the application nozzle 31 after applying the black oil-based paint to the discharge surface of the application nozzle 31 and performing ultrasonic cleaning similar to that of the first embodiment. It was confirmed that erosion due to cavitation was concentrated in the coating nozzle 31 from which the most oil-based paint was removed in and around the discharge hole 36.

  Then, next, this application nozzle 31 was repeatedly subjected to ultrasonic cleaning in a cleaning tank containing diacetone alcohol and pure water in the same manner as in Example 1. When the discharge surface of the coating nozzle 31 was observed with a microscope after the ultrasonic cleaning was completed, it was confirmed that there was a damaged portion at the edge of the discharge hole 36 and erosion concentrated on the discharge hole was generated.

  Furthermore, when this coating nozzle 31 was assembled and applied to the plasma display back plate as a substrate with the coating apparatus 1 shown in FIG. 1 in the same manner as in Example 1, the coating amount was reduced for each applied fine groove. There was variation, and when the coated substrate was dried, spots were seen and the substrate became defective.

Example 2
Next, a coating nozzle 41 according to another embodiment of the present invention shown in FIG. 6 was prepared. The outer shape, material, shape, number, and pitch of the application nozzle 41 are the same as those of the application nozzle used in Example 1. The depressions 47 of the application nozzle 41 are formed in one row on one side of the discharge holes 46 forming a substantially straight row 401, and the number thereof is 1927. The recess 47 has a diameter of 100 μm and a depth of 100 μm, and the pitch of the recess 47 is 0.48 mm. The distance between the row 401 formed by the discharge holes 46 and the row 402 formed by the depressions 47 is 1500 μm.

  First, FIG. 7 shows a photograph of the appearance of the discharge surface of the application nozzle 41 after applying the black oil-based paint to the discharge surface of the application nozzle 41 and performing ultrasonic cleaning similar to that of the first embodiment. The application nozzle 41 has confirmed that the most oil-based paint was removed in the hollow part 47 and its periphery.

  Then, next, this application nozzle 41 was repeatedly subjected to ultrasonic cleaning in a cleaning tank containing diacetone alcohol and pure water in the same manner as in Example 1. When the discharge surface of the application nozzle 41 was observed with a microscope after the ultrasonic cleaning was completed, it was confirmed that there was no damaged portion of the discharge hole 46 and no erosion concentrated only on the discharge hole 46.

  Further, the coating nozzle 41 was assembled, and applied to the plasma display back plate as a substrate by using the coating apparatus 1 shown in FIG. It was confirmed that there was no coating failure.

Comparative Example 2
Next, the application nozzle 51 shown in FIG. 8 was prepared. The outer shape, material, shape, number, and pitch of the application nozzle 51 are the same as those of the application nozzle used in Example 1. The depressions 57 of the application nozzle 51 are formed in a single line on one side of the discharge holes 56 forming a substantially straight line 501, and the number thereof is 964. The depressions 57 have a diameter of 100 μm and a depth of 100 μm, and the pitch of the depressions 57 is 0.96 mm. The distance between the row 501 formed by the discharge holes 56 and the row 502 formed by the depressions 57 is 1500 μm.

  FIG. 9 shows a photograph of the appearance of the discharge surface in the application nozzle 51 after applying the black oil-based paint to the discharge surface of the application nozzle 51 and performing ultrasonic cleaning similar to that in the first embodiment. It was confirmed that the oil-based paint was removed from the application nozzle 51 around the recess 57 and the discharge hole 56.

  Then, next, this application nozzle 51 was repeatedly subjected to ultrasonic cleaning in a cleaning tank containing diacetone alcohol and pure water in the same manner as in Example 1. When the discharge surface of the coating nozzle 51 was observed with a microscope after the ultrasonic cleaning was completed, it was confirmed that there was a damaged portion at the edge of the discharge hole and erosion concentrated on the discharge hole was generated.

  Furthermore, when this coating nozzle 51 was assembled and applied to the plasma display back plate as a substrate with the coating apparatus 1 shown in FIG. 1 in the same manner as in Example 1, the coating amount was reduced for each applied fine groove. There was variation, and when the coated substrate was dried, spots were seen and the substrate became defective.

  The present invention can be applied not only to a coating nozzle used for a plasma display member but also to a color filter for a liquid crystal display or a coating nozzle used for coating a coating liquid in an organic EL, and its application range is limited to these. It is not a thing.

DESCRIPTION OF SYMBOLS 1 Application | coating apparatus 2 Substrate 3 Coating liquid container 4 Piping 5 Opening / closing valve 6 Discharge control gas source 7 Piping 8 Pressure reducing valve 9 Piping 10 Discharging valve 11 Pressure reducing valve 12 Controller 20 Coating nozzle unit 21 Coating nozzle 22 Manifold 23 Supply port 24 Liquid storage Part 25 Space part 26 Ejection hole 27 Depression part 31 Application nozzle 36 Ejection hole 41 Application nozzle 46 Ejection hole 47 Depression part 51 Application nozzle 56 Ejection hole 57 Depression part 201 Row 202 formed by the ejection hole 202 Depression part formed 203 Row 204 formed by the hollow portion 205 Row formed by the hollow portion 301 Row formed by the discharge hole Row 401 formed by the discharge hole Row 402 formed by the hollow portion 501 Row formed by the hollow portion 502 Row formed by the discharge hole Row 502 formed by the hollow portion A Area of the hatched portion

Claims (5)

  An application nozzle in which a plurality of discharge holes for discharging a paste are formed in a substantially straight line, wherein the application nozzle includes a plurality of concave and convex portions having a depression shape and / or a projection shape. The projections and depressions are sandwiched between two straight lines passing through the ejection holes located at both ends of the row perpendicular to the row formed by the ejection holes on the nozzle surface where the plurality of ejection holes are formed. In the region formed so as to form a row substantially parallel to the row formed by the discharge holes, and the row formed by the concavo-convex portions is composed of concavo-convex portions whose number is 90% or more of the number of the discharge holes. An application nozzle characterized by that.   2. The coating nozzle according to claim 1, wherein a plurality of rows formed by the uneven portions are formed, and one or more rows are arranged on both sides of the row formed by the discharge holes.   3. The coating nozzle according to claim 1, wherein an interval between the uneven portions forming a row is equal to or less than a maximum interval of the discharge holes forming the row.   A method for applying a paste, comprising applying the paste by discharging the paste onto a substrate using the application nozzle according to claim 1, which has been subjected to ultrasonic cleaning.   A method for producing a member for a plasma display, wherein the phosphor paste is applied using the paste application method according to claim 4.