JP4228601B2 - Method for forming phosphor layer of plasma display back plate and plasma display back plate - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a plasma display back plate (PDP) in which a phosphor layer is formed on a side surface of a partition wall and a groove bottom between the partition walls, and a method for forming the phosphor layer.
[0002]
[Prior art]
FIG. 1 shows an example of the structure of an AC drive, surface discharge, and back reflection type color PDP which is currently mainstream.
In FIG. 1, the color PDP has a front side substrate (11, 17, 18, 41X, 41Y, 42) and a rear side substrate (21, 22, 24, 28R, 28G, 28B, 29, A) formed by frit seals. It has a vacuum sealed structure.
A plurality of address electrodes (A) for generating an address discharge are formed on the substrate surface on the back side, and a dielectric layer 24 is formed so as to cover the electrodes as necessary. Further, a large number of stripe-shaped barrier ribs 29 for physically dividing the discharge so as to sandwich the address electrode A are provided, and phosphor layers (28R, 28G, 28B) are formed in the elongated grooves between the barrier ribs 29. Is formed.
[0003]
The phosphor layers (28R, 28G, 28B) are formed on the side surface of the partition wall 29 on the back plate and the bottom of the groove between the partition walls 29. This phosphor layer emits ultraviolet light of xenon emitted by the main discharge, and emits fluorescence of three primary colors of visible light separately for each groove, and becomes a color display when viewed from the front side. Only the surface that has actually been irradiated with ultraviolet light emits visible light.
[0004]
The diameter of the phosphor particles forming the phosphor layer (28R, 28G, 28B) is usually 5 to 10 μm. In principle, the thickness of the phosphor layers (28R, 28G, 28B) formed of the phosphor particles may be twice the particle diameter when densely packed. Since a phosphor in a place not exposed to ultraviolet rays does not emit light, it is basically wasted. In addition, since the phosphor is expensive, it is preferable to form phosphor layers (28R, 28G, 28B) in which the amount used is reduced as much as possible. However, in order to reflect the emitted light that passes through the back surface of the phosphor layer (28R, 28G, 28B), the phosphor layer (28R, 28G, 28B) is preferably thick. However, if there is a substance that reflects the wavelength of the fluorescent light emitted on the back surface of the phosphor layer (28R, 28G, 28B), the thickness of the phosphor layer (28R, 28G, 28B) should be 2 to 3 times the particle diameter. That's fine. In addition, if there is a substance that absorbs ultraviolet rays on the surface of the phosphor, the light emission efficiency decreases accordingly. For this purpose, the phosphor layers (28R, 28G, 28B) are layers made only of phosphor particles.
[0005]
Here, the partition walls 29 are for separating the discharge region, and the material is required to be able to withstand plasma discharge. Specifically, it consists of inorganic particles having a high melting point for maintaining the glass component and shape as a binder. As a basic structure of the partition wall 29, a stripe-shaped structure is shown in FIG. 2A, a lattice-shaped structure is shown in FIG. 2B, and examples of other shapes are shown in FIG. The size of the partition wall 29 is generally in the range of 30 to 70 μm in width, 100 to 200 μm in height, and 100 to 500 μm in pitch.
[0006]
The phosphor layers (28R, 28G, 28B) are formed not only on the bottom surface portion between the partition walls 29 of the rear substrate, but also on the side surfaces of the partition walls. The reason is that the luminance is insufficient only by light emission from the bottom surface, so that the light emission area is increased. In addition, it is not preferable that the phosphor adheres to the upper surface of the partition wall 29. If the phosphor adheres, it is removed by a method such as polishing.
A partition wall 29 having the structure shown in FIGS. 2B and 2C has been proposed and partially put into practical use, mainly for the purpose of increasing the light emission area as compared with the structure of FIG.
[0007]
In any case, in the normal case, the phosphor layer (28R, 28G, 28B) is thicker and the light emission luminance at that portion increases. However, the increase rate of the light emission luminance decreases as the thickness increases. On the other hand, if it is too thick, the light emitting area tends to decrease. Therefore, there is an optimum thickness. In general, the closer to the upper surface of the partition wall 29, the closer to the ultraviolet ray generating portion, the higher the emission luminance. Also in this respect, as a method for forming the phosphor layers (28R, 28G, 28B), a formation method capable of finely controlling the thickness of the phosphor layers (28R, 28G, 28B) is preferable. Furthermore, since the phosphor is relatively expensive, a formation method with less waste is preferable.
The conventional manufacturing method of the phosphor layer (28R, 28G, 28B) is as follows. The phosphor layer paste made of a phosphor and an organic substance called a vehicle component for making a paste and a solvent component is put between the partition walls 29, In this method, after adhering to the part, the solvent is evaporated, and then baking is performed to remove organic substances.
[0008]
Conventional methods for putting a predetermined amount of the phosphor layer paste between the predetermined barrier ribs 29 are a screen printing method and a dispenser method. Then, during or after the process of inserting the phosphor layer paste, an operation of adhering to the side surfaces of the partition walls 29 is performed to obtain a desired shape as much as possible.
To describe an example in more detail, first, a fluid phosphor layer paste is injected into a predetermined portion by a predetermined amount by a screen printing method or a dispenser method, and then the substrate is tilted so that the phosphor is also applied to the side surface of the partition wall 29. Allow the layer paste to spread. This operation is continued until the solvent of the phosphor layer paste is volatilized, the viscosity of the paste gradually increases, and the fluidity is lost, so that a desired thickness of the phosphor layer (28R, 28G, 28B) can be obtained. In addition to tilting the substrate, the phosphor layers (28R, 28G, 28B) may be made more uniform by applying minute vibration, ultrasonic vibration, or the like to the substrate. Further, in order to reduce the thickness of the phosphor layers (28R, 28G, 28B) to the necessary and minimum thickness, the amount of the phosphor layer paste to be injected is adjusted.
[0009]
The problem with the conventional method described above is that the phosphor layer (28R, 28G, 28B) is not formed on the side surface of the partition wall 29 with a desired thickness. As shown in FIG. 3, the thickness of the phosphor layer 28 tends to be thinner than a predetermined thickness at the upper part of the side surface of the partition wall 29 and thicker than the predetermined thickness near the bottom surface. Further, when the phosphor layer 28 on the bottom surface is thickened, an address discharge start voltage (voltage for generating discharge between the address electrode and one electrode of the main electrode pair (41X, 41Y in FIG. 1) on the front plate). ) Rises and it becomes difficult to secure a dynamic drive margin necessary for expressing the image. These problems occur in any of the partition structures shown in FIGS. 2 (a), 2 (b) and 2 (c). The main reason is that the adhesive strength of the phosphor layer paste to the side surfaces of the barrier ribs 29 is insufficient.
[0010]
The following countermeasures have been proposed for this problem. First, in Japanese Patent Laid-Open No. 2000-260330 shown in FIG. 4, each groove is filled with the phosphor layer paste 28a by a screen printing method or a dispenser method, and the partition walls 29 are located below the substrate 21. A method of drying the phosphor layer paste 28a in a state is disclosed. That is, in order to insert the phosphor layer paste 28a by the screen printing method or the dispenser method, it may be easier that the viscosity is low. The phosphor layer 28 is formed at the bottom between the two, and hardly adheres to the side surfaces of the partition walls 29 as shown in FIGS.
As the flow shaping operation of the phosphor layer paste 28a, if the partition wall 29 is turned downward as shown in FIG. 4, the paste hangs down on the side surface of the partition wall 29, and the solvent evaporates with time and the fluidity decreases. In the end, we take advantage of the lack of liquidity.
In the above-mentioned JP-A-2000-260330, the thickness of the desired phosphor layer shape is defined. (1) The thickness of the phosphor layer 28 formed on the side face of the partition wall 29 is set at the groove bottom between the partition walls 29. It is described that the thickness of the formed phosphor layer 28 is ½ or more, and (2) that both have substantially the same thickness. Further, since the illuminance of ultraviolet rays is higher because the portion closer to the top of the partition wall 29 is closer to the plasma that is the ultraviolet ray source, the ultraviolet light can be effectively utilized by increasing the thickness of the phosphor layer 28 near the top portion of the partition wall 29. You can do it. Also from this point, a method for finely controlling the thickness of the phosphor is demanded.
[0011]
Furthermore, in the above-mentioned Japanese Patent Laid-Open No. 2000-260330, it is said that the actual thickness of the phosphor layer 28 is 10 to 20 μm at the groove between the partition walls 29. Further, it is said that the phosphor layer 28 has a thickness of 10 μm or more that exhibits a sufficient effect as a reflection layer.
[0012]
A desirable phosphor layer shape is also described in JP-A-11-297213. That is, when the discharge space volume defined at the start and end of the barrier ribs on both sides of the substrate and the upper surface of the barrier rib is 100, the substantial discharge space volume excluding the volume occupied by the phosphor layer is 50 to 85. %, And the thickness of the bottom phosphor layer is 10 to 25% of the partition wall height, and the thickness of the partition wall side phosphor layer at the position 20% below the partition wall height from the top of the partition wall is 10 to 10% of the partition wall height. It is described as a phosphor screen that is 25%. In addition, as a means for obtaining the structure, a method is disclosed in which the phosphor layer paste is filled so as to fill the grooves between the partition walls, and the volume is reduced by drying. The actual phosphor layer thickness is preferably 10 to 40 μm. If the thickness is 10 μm or less, the amount of light emitted from the back surface is large and the luminance is low, and if it is 40 μm or more, the brightness is not further increased. In order to obtain the above-mentioned shape by this method, limiting conditions for the viscosity and fluidity of the paste are also shown. However, this method is not sufficient only by specifying the viscosity and fluidity of the paste, and in practice, the thickness of the phosphor layer on the side surface close to the top of the partition tends to be 10 μm or less. Moreover, the thickness of the phosphor layer at the bottom between the barrier ribs tends to be thicker than necessary.
Regarding this problem, in Japanese Patent Application Laid-Open No. 2000-208057, as a method for obtaining a phosphor layer having a structure described in Japanese Patent Application Laid-Open No. 11-297213, the phosphor layer paste is applied to the groove-shaped portion between the partition walls two or more times. A method of performing a series of steps of applying and drying is disclosed. However, even with this method, it has been difficult to obtain a phosphor layer having a desired shape.
[0013]
A completely different method has been proposed as a method of making the phosphor layer have a constant thickness, whether on the side surface of the partition walls or at the bottom of the groove between the partition walls. The method is a method in which a phosphor layer paste layer formed to a uniform thickness on another transfer support is embedded and transferred along the irregularities of the partition walls. However, this method becomes more difficult as the height of the groove-like portion between the partition walls becomes higher and the width becomes narrower. Also. It is difficult with this method to form a phosphor layer in a grid-like depression instead of a groove.
[0014]
[Problems to be solved by the invention]
As a method for forming the phosphor layer, the conventional fluid layer paste is inserted between the partition walls, and the problem of the flow shaping is that the phosphor layer paste does not adhere to the side walls of the partition wall. It is an object to propose a method that can improve the sufficient state and control the phosphor layer in a desired shape. Another object of the present invention is to provide a method, a material, and the like that can control the thickness of the phosphor layer on the side surface near the top of the partition wall to a desired thickness. That is, an object of the present invention is to provide a forming method that eliminates the difficulty in reliably obtaining a desired shape of a phosphor layer, which is a problem of a known method.
[0015]
[Means for Solving the Problems]
The invention according to claim 1 is a method for forming a phosphor layer of a plasma display back plate,On boardFluidity in the part between the specified partitionsContains cellulosic resinInsert the phosphor layer paste,Tilt the substratePerform a shaping operation to attach the phosphor layer paste in a preferred shape to the side walls of the barrier ribs,By cooling and curingFluidity of phosphor layer paste on the side wallEvaporate the phosphor layer paste solvent after reducing or eliminatingIs a method for forming a phosphor layer of a back plate of a plasma display.The invention described in claim 2 is characterized in that the method of evaporating the solvent of the phosphor layer paste is a method of depressurizing the phosphor layer of the plasma display back plate according to claim 1. It is a forming method.
[0016]
Claim 33. The plasma display back plate according to claim 1, wherein the shaping operation for attaching the phosphor layer paste to the side face of the partition wall is performed while the phosphor layer paste is being inserted. This is a method for forming a phosphor layer.
[0017]
Claim 4The invention described in the above item is characterized in that the operation of reducing or eliminating the fluidity of the phosphor layer paste formed on the side surface of the partition wall is performed during or after the shaping operation of the phosphor layer paste. It is a formation method of the fluorescent substance layer of the plasma display backplate of Claim 1 thru | or 3.
[0018]
Claim 5The invention described in 1 is characterized in that the flow shaping operation of the phosphor layer paste is performed and the fluidity of the phosphor layer paste is lowered while observing the shape of the inserted phosphor layer paste. The method for forming a phosphor layer of a plasma display back plate according to any one of claims 1 to 4.
[0019]
Claim 66. The invention according to claim 1, wherein the color balance of the three fluorescent colors is adjusted by adjusting the adhesion state of the phosphor layer paste for each fluorescent color. It is the formation method of the fluorescent substance layer of the plasma display backplate.
[0020]
Claim 7In the invention described in, the method of fluid shaping the phosphor layer paste on the side surface of the partition wall is to place a substrate filled with the phosphor layer paste on an inclined rotation plate, and rotate at a predetermined inclination angle and rotation speed, The method for forming a phosphor layer of a plasma display back plate according to any one of claims 1 to 6, wherein the phosphor layer paste is attached to a side face of a partition wall.
[0023]
Claim 8The invention described in 1 is a plasma display back plate, wherein the phosphor layer is formed by the method for forming a phosphor layer of the plasma display back plate according to any one of claims 1 to 7.
[0024]
DETAILED DESCRIPTION OF THE INVENTION
In this specification, the term “plasma display back plate” refers to the “back plate” of the plasma display panel. Of course, if the “back plate” and the conventionally known “front plate” are combined to form the entire panel, the entire panel can be created.
[0025]
Hereinafter, embodiments of the present invention will be described.
In order to make the phosphor layer paste adhere to the side wall of the barrier rib in a preferred shape, as a known shaping operation for flowing the paste, there is a method of inclining the substrate and the upper surface of the barrier rib as shown in FIG. There are a method and a combination of these methods, and they can be used in the present invention. Furthermore, vibration / ultrasonic vibration may be used as auxiliary means.
[0026]
When the fluidity of the phosphor layer paste is too high to perform the flow shaping operation, it is necessary to increase the viscosity. In the case of the radiation curing phosphor layer paste, this can be achieved by irradiating a small amount of radiation. In the phosphor layer paste in which the viscosity changes with temperature, this can be achieved by lowering the temperature.
[0027]
The shape of the phosphor layer paste is preferably observed using a normal microscope or a CCD microscope. In this case, the shape can be easily observed by illuminating from an oblique direction. In addition, it is convenient to use a three-dimensional image recognition device such as a confocal microscope capable of obtaining depth information.
[0028]
As a method of inclining the substrate, there is a method of simply inclining left and right when the partition walls are striped. When the partition wall has a cross-girder structure, there is a method of sequentially tilting in four directions, but as a more preferable method, a method of rotating the glass substrate 21 on the tilted turntable 51 as shown in FIG. There is. In this case, the state of adhesion to the partition walls 29 can be changed by changing the tilt angle and the rotation speed. This method can also be used for the stripe-shaped partition walls 29. By changing the rotation speed within one rotation, it can be non-uniformly attached to the surrounding partition wall 29.
[0029]
When using a paste whose fluidity decreases or disappears when irradiated with radiation, the method of reducing or eliminating the fluidity of the phosphor layer paste at the desired location is a method of irradiating radiation from an oblique direction. There is. This method will be described in detail later. As another method, there is a method using radiation with a short working distance. For example, in electron beam irradiation, the working distance varies greatly depending on the acceleration voltage, and it is also absorbed by nitrogen or the like between the irradiation apparatus and the object to be irradiated, so that the hardening action is reduced. Can be eliminated. There is also a method using short wavelength ultraviolet rays. Also in this case, the working distance can be adjusted because it is absorbed by the intermediate air.
[0030]
In addition, when using a method in which the phosphor layer paste flows down the side surfaces of the barrier ribs using a screen printing method as disclosed in Japanese Patent Application Laid-Open No. 2000-208057, radiation is applied so that only the side surface portions of the barrier ribs are cured. Using a method of irradiating from an oblique direction, the phosphor layer paste can be attached to the side surfaces of the barrier ribs.
[0031]
In general, it is necessary that the amount of paste inserted is an amount capable of forming a phosphor layer with a predetermined thickness. If it deviates from the predetermined amount, the light emission luminance is deviated and the balance of the three colors is deteriorated. This phenomenon occurs partly and entirely. If there is a single gap, that is, if the partition is striped, it is a single groove, and if the partition is in a matrix shape (cross-girder), it is a single ridge-like part. It is necessary to make the amount of the phosphor layer paste incorporated as uniform as possible.
However, in the method of performing the shaping operation by inserting the fluid phosphor layer paste, which is one of the present inventions, partial unevenness can be made uniform by the shaping operation. Therefore, it is necessary to insert a predetermined amount of the phosphor layer paste into the gaps or ridges of each partition wall.
However, in the method of the present invention, the cross-sectional shape of the phosphor layer can be made to have a desired shape fairly accurately, so that the light emission luminance can be adjusted as follows. Therefore, even if the amount of the phosphor layer paste inserted is slightly deviated from the predetermined amount, the light emission luminance can be set to the predetermined value. The method utilizes the fact that the emission luminance is high near the top of the partition and low at the bottom. That is, when a larger amount of the phosphor layer paste is contained, the phosphor layer near the top of the partition is made thinner. On the other hand, when the amount of the phosphor layer paste inserted is less than a predetermined amount, the thickness of the phosphor layer on the side surface near the top of the barrier rib is increased from a predetermined value. It is an advantage of the present invention that such shaping control is possible.
[0032]
As a general rule, the three color phosphors are separately subjected to the shaping operation. However, the three colors of paste can have the same viscosity, and the three colors can be shaped simultaneously. Even when the intervals between the barrier ribs are unequal, it is possible to simultaneously shape the three colors by adjusting the viscosity of the phosphor layer paste of each color. As a method of adjusting the viscosity, there is a method of adjusting radiation irradiation for each color. In this case, a mask is used so as not to irradiate unnecessary portions.
[0033]
As a paste characterized in that it changes from a fluid state to a non-fluid state when irradiated with radiation, basically known pastes for photosensitive phosphor layers can be used. .
Examples of radiation that has the effect of reducing and eliminating the fluidity of the phosphor layer paste include visible light, ultraviolet rays, and electron beams. In most cases, pastes that cure with visible or ultraviolet light can be cured with electron beams. In the case of electron beam curing, a polymerization initiator is unnecessary in most cases.
[0034]
The photosensitive phosphor layer paste comprises at least a phosphor and a photosensitive component. Examples of known pastes include, for example, JP-A-10-90889, JP-A-10-283927, JP-A-11-65086, No. 11-297213 and JP-A No. 2000-208057. Any of them can be used as the radiation curable phosphor layer paste of the present invention. In the present invention, light is irradiated in a fluid state to make it substantially non-fluid. On the other hand, in the above-mentioned two known materials and other normal usage methods, the coating is applied to a desired place, dried, and then exposed and cured. In this case, “curing” is performed by irradiating light that is already in a solid state to reduce the solubility in a solvent or improve the resistance to sandblasting.
[0035]
In the case of radiation curing, depending on the type of the polymerization initiator, oxygen damage may occur and the surface may not be cured. However, in most compositions, it cures to the extent that fluidity disappears. In the unlikely event that oxygen damage occurs, a polymerization initiator having no oxygen damage may be used. Also in the case of electron beam curing, oxygen damage occurs, so that the electron beam irradiation chamber is usually replaced with nitrogen. However, even if oxygen damage occurs, it is cured to such an extent that fluidity disappears, so that nitrogen substitution is unnecessary.
[0036]
The above paste is generally composed of at least a polyfunctional or bifunctional monomer, oligomer, or polymer used for the photosensitive paste for baking and a photoinitiator. Furthermore, a polymer and a solvent for adjusting fluidity, and a storage stabilizer may be included. Specifically, an acrylic material is actually preferable as a polyfunctional or bifunctional monomer, oligomer, or polymer.
[0037]
Note that it is sufficient that the fluidity is eliminated by irradiation with radiation, and it is not necessary to cure. Therefore, the amount of the photopolymerization initiator can be reduced as compared with the photocurable paste. The amount of monofunctional polymer or bifunctional polymer / oligomer may be increased. However, it is generally preferable to increase the content of the inorganic component as much as possible. In addition, the viscosity of the paste should be relatively high so that the phosphor does not precipitate in the paste.
In order to adjust the viscosity, a solvent, a polymer and a dispersant are added. The appropriate viscosity varies depending on the method of filling between ribs and the method of spreading on the side surface of the partition wall. When the fluidity is very high, for example, it becomes difficult to fill with a screen printing method, but it becomes easy to supply with a dispenser. Further, when the substrate is extended to the side surface of the partition wall, the substrate can be easily extended only by inclining. However, in some cases, it becomes easy to separate the phosphor and the photosensitive component, or it is necessary to fill in a large amount.
[0038]
FIG. 7 shows one means for adjusting the fluidity of the phosphor layer paste 28 in a portion (region) near the top of the partition wall by irradiating light from an oblique direction. In this case, the adjacent partition wall 29 becomes a light shielding material, and unnecessary portions are not irradiated. Further, in the case of FIG. 7, the light is radiated while the substrate 21 is inclined to eliminate the fluidity. However, the light may be radiated after returning to the horizontal state.
More specifically, for example, the phosphor layer paste is adhered and fixed to the side surfaces of the partition walls 29. That is, (1) the phosphor layer paste is attached to one side surface by being inclined obliquely in a certain direction. Then, the phosphor layer paste on the barrier ribs 29 is observed to fall down and the phosphor layer paste on the barrier ribs 29 is irradiated obliquely when the thickness is just right. Eliminate fluidity. (2) Next, it is tilted to the opposite side and attached to the side surface of the opposite partition wall 29, the substrate 21 is returned horizontally, and light is applied obliquely to make the phosphor layer paste on the partition wall 29 fluid. lose. (3) Irradiate light vertically to eliminate the fluidity of the phosphor layer paste at the bottom between the barrier ribs 29. However, in practice, if (1), (2), and (3) are performed in completely separate steps, a step occurs at the boundary of the portion where the fluidity is lost. Therefore, the irradiation angle is continuously changed during irradiation with light. Or irradiating light while continuously changing the inclination of the substrate, or adjusting the intensity of light continuously.
[0039]
As another method, the substrate 21 is inclined and the phosphor layer paste is caused to flow on the side surfaces of the partition walls 29, and the fluidity of the phosphor layer paste at a required portion (side surface near the top of the partition walls 29) in that state is eliminated. There is. In this method, if the viscosity of the phosphor layer paste is too low, as shown in FIGS. 5A and 5B, the phosphor layer paste layer near the top is thin or almost absent. However, as the viscosity of the phosphor layer paste increases, the portion near the top also increases. Therefore, the viscosity of the phosphor layer paste is adjusted so that this state can be obtained. The method of adjusting the viscosity is radiation irradiation in the radiation polymerization type, and temperature adjustment in the heat flow type.
[0040]
In addition, as for the wavelength of light, when the fluidity of the phosphor layer paste is lost only in the portion close to the top of the partition wall 29, short wavelength ultraviolet rays having a large absorption in the air are used. For example, an excimer laser of 147 nm of xenon and 193 nm of ArF is used. Since the height of the partition wall 29 is 100 μm to 200 μm, only the photosensitive phosphor layer paste near the top of the partition wall 29 loses fluidity.
[0041]
In the cooling non-fluidization type phosphor layer paste, in the state where there is no solvent, it is necessary to remain solidified without being fluidized even if the temperature is raised during firing. The vehicle material for that purpose needs to be a material that does not melt and sublime or decompose when heated. Actual materials include resins used for baking pastes, such as cellulose resins and acrylic resins. When this type of paste is used, it is necessary to evaporate the solvent in a state where the required shape is obtained by cooling, and a method of reducing the pressure is effective in addition to leaving it alone. Cellulosic resins are most often used as pastes for baking. However, it is often difficult to impart photosensitivity. In this case, a method of cooling and non-fluidizing is preferable.
[0042]
There is also a method using a temperature difference between the substrate base and the upper surface of the partition wall. That is, the paste between the heated partition walls of the substrate is fluid, but the atmosphere is adjusted so that the paste loses fluidity at a temperature near the upper surface of the partition walls. Place on the heating plate, fill the heated paste between the partition walls of the heated substrate with all three colors (by three screen printings), then tilt the substrate and use the phosphor layer along the side of the partition wall Let the paste flow. Here, as the paste approaches the top of the partition, the temperature decreases, the fluidity decreases, and the fluidity disappears near the top of the partition. Next, the paste is similarly fixed to the side surface of the partition wall by inclining to the opposite side. If the temperature of the substrate is lowered while the inclination of the substrate is sequentially reduced, the fluidity of the paste is sequentially lost, and a desired shape can be obtained. Next, the solvent of the paste is vacuumed or left to dry. Then, it will be in the state which does not fluidize even if it heats.
[0043]
As a solvent, there is a method of combining a good solvent and a poor solvent. As both solvents evaporate, they become gel and lose fluidity. Further, it is generally easy to adjust the viscosity.
When a solvent is used in the phosphor layer paste, the solvent is removed before firing. The method may be any of vacuum (reduced pressure) drying, heat drying, and natural drying. However, if the solvent is removed too quickly, cracks may occur. In the case of the cooling non-fluidization type, the solvent is removed in the cooled state. In that case, vacuum (reduced pressure) drying is preferred.
[0044]
Moreover, the paste which hardens | cures by hardening | curing agent addition (mixing) can also be used as a paste for fluorescent substance layers. As a resin suitable for this, it must be a resin that disappears upon firing, and an acrylic resin can be used.
[0045]
Further, as the phosphor layer paste, a paste that cures when heated can be used. The heat-curing type does not cure (substantially loses fluidity) in a short time (instantaneous to several seconds) as much as radiation curing, but if it is far-infrared heating, it cures in about 10 seconds. Yes, it can be used as appropriate.
【The invention's effect】
The phosphor layer of the plasma display back plate can be formed on the side surface of the barrier rib with a desired thickness, and the utilization efficiency of the phosphor for light emission can be increased. Luminous efficiency can also be increased. Furthermore, it becomes possible to form a phosphor layer having a shape that has been difficult with the conventional method, it is possible to adjust the light emission luminance, and it is easier than ever to improve the color balance.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram showing an example of the internal structure of a PDP.
FIG. 2 is an explanatory diagram showing a shape example of a partition wall.
FIG. 3 is a cross-sectional view illustrating the thickness of a phosphor layer.
FIG. 4 is an explanatory view showing an example of a drying method when forming a phosphor layer of a conventional PDP.
FIG. 5 is an explanatory view showing a state in which a phosphor layer paste is inserted between barrier ribs by a conventional method.
FIG. 6 is an explanatory view showing a method for forming a phosphor layer on a partition wall of a lattice-like partition wall (hole-shaped light emitting portion).
FIG. 7 is an explanatory view showing a method for selectively reducing the fluidity of the phosphor layer paste near the upper surface of the barrier ribs by irradiating radiation from an oblique direction.
[Explanation of symbols]
1 ... AC type 3-electrode surface discharge structure PDP
11 ... Front side glass substrate
17 ... Dielectric layer
18 ... Protective layer
21 ... Back side glass substrate
22 ... Underlayer
24 ... Dielectric layer
28, 28R, 28G, 28B ... phosphor layer
29, 29b ... partition wall
30 ... discharge space
41. Transparent conductive film
42 ... Metal film (Bus electrode)
51. Turntable
A ... Address electrode
D: Direction in which the phosphor layer paste flows
H ... Radiation
L ... line
X, Y ... Sustain electrode

Claims (8)

In the method for forming a phosphor layer of a plasma display back plate, a phosphor layer paste containing a flowable cellulose resin is put into a predetermined portion between partition walls on a substrate, and the substrate is tilted for phosphor layer Perform shaping operation to attach the paste to the side wall of the barrier rib in the preferred shape, and reduce or eliminate the fluidity of the phosphor layer paste on the side wall of the barrier wall by cooling and curing, then evaporate the solvent of the phosphor layer paste A method for forming a phosphor layer of a back plate of a plasma display, comprising: The method for forming a phosphor layer of a plasma display back plate according to claim 1, wherein the method of evaporating the solvent of the phosphor layer paste is a method of reducing the pressure. The formation of the phosphor layer of the plasma display back plate according to claim 1 or 2, wherein the shaping operation for attaching the phosphor layer paste to the side wall of the partition wall is performed while the phosphor layer paste is being put in. Method. The operation of reducing or eliminating the fluidity of the phosphor layer paste formed on the side surface of the partition wall is performed during or after the shaping operation of the phosphor layer paste. A method for forming a phosphor layer of the plasma display back plate as described. 5. The flow shaping operation of the phosphor layer paste and the lowering of the fluidity of the phosphor layer paste are performed while observing the shape of the inserted phosphor layer paste. The formation method of the fluorescent substance layer of the plasma display backplate in any one. 6. The plasma display back plate according to claim 1, wherein the color balance of the three fluorescent colors is adjusted by adjusting the adhesion state of the phosphor layer paste for each fluorescent color. Method for forming phosphor layer. The method of fluid shaping the phosphor layer paste on the side surfaces of the barrier ribs is to place a substrate filled with the phosphor layer paste on an inclined rotating plate, rotate at a predetermined tilt angle and rotation speed, and rotate the phosphor layer side surfaces to the side surfaces of the barrier ribs. 7. The method for forming a phosphor layer of a plasma display back plate according to claim 1, wherein the body layer paste is applied. A plasma display back plate comprising a phosphor layer formed by the method for forming a phosphor layer of a plasma display back plate according to claim 1.

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