JP2004022180A - Plasma display back surface plate and method for forming phosphor layer thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To form a phosphor layer of a back surface plate of a plasma display in a desired thickness on a side face of a partition wall. <P>SOLUTION: A method for forming the phosphor layer of the back surface plate includes the steps of using a paste for a photosensitive phosphor layer at least in the phosphor layer, injecting the paste for the photosensitive phosphor layer between partition walls, then increasing a viscosity of the paste by irradiating with a light so as to be easily adhered to the side face of the partition wall, inclining the substrate until a top of the partition wall becomes a lower side in some cases, adhering the paste for the phosphor layer to the sidewall, and irradiating with the light when it becomes a desired shape by observing to vanish fluidity. There may be a method for vanishing the fluidity by the change of the temperature by using the paste for the phosphor which changes from the fluidity to a non-fluid state as the viscosity changes according to the temperature as well. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD 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 a color PDP of AC drive, surface discharge, and back reflection type which is currently mainstream.
In FIG. 1, a color PDP has a front substrate (11, 17, 18, 41X, 41Y, 42) and a rear substrate (21, 22, 24, 28R, 28G, 28B, 29, A) with frit seals. It has a vacuum sealed structure.
A plurality of address electrodes (A) for generating 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 partitions 29 for physically dividing discharges are provided so as to sandwich the address electrode A, and phosphor layers (28R, 28G, 28B) are provided in elongated grooves between the partitions 29. Is formed.
[0003]
The phosphor layers (28R, 28G, 28B) are formed on the side surface of the partition wall 29 of the back plate and the bottom of the groove between the partition walls 29. The phosphor layer emits three primary colors of visible light fluorescent light separately for each groove in response to xenon ultraviolet light emitted by the main discharge, and provides a color display when viewed from the front side. Visible light is emitted only on the surface that is actually exposed to ultraviolet light.
[0004]
The diameter of the phosphor particles forming the phosphor layers (28R, 28G, 28B) is usually 5 to 10 μm. The thickness of the phosphor layers (28R, 28G, 28B) formed of the phosphor particles may be, in principle, twice as large as the particle diameter when they are densely packed. Phosphors that are not exposed to ultraviolet light do not emit light and are basically wasted. Further, since the phosphor is expensive, it is preferable to form the phosphor layers (28R, 28G, 28B) with the usage amount reduced as much as possible. However, in order to reflect light emitted from the back surface of the phosphor layers (28R, 28G, 28B), the phosphor layers (28R, 28G, 28B) are preferably thick. However, if there is a substance that reflects the wavelength of the emitted fluorescent light on the back surface of the phosphor layers (28R, 28G, 28B), the thickness of the phosphor layers (28R, 28G, 28B) should be two to three times the particle diameter. Just fine. In addition, when there is a substance that absorbs ultraviolet light on the surface of the phosphor, the luminous efficiency is reduced accordingly. The phosphor layers (28R, 28G, 28B) for that purpose are layers of only phosphor particles.
[0005]
Here, the partition wall 29 is for separating the discharge region, and is made of an inorganic material because the material needs to withstand plasma discharge. Specifically, it is composed of a glass component as a binder and inorganic particles having a high melting point for maintaining the shape. 2A shows a basic structure of the partition wall 29, FIG. 2B shows a lattice-like structure, and FIG. 2C shows an example of other shapes. 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 between the partitions 29 on the rear substrate but also on the side surfaces of the partitions. The reason for this is to increase the light emitting area because the luminance is insufficient only by the light emission from the bottom surface. 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.
The partition wall 29 having the structure shown in FIGS. 2B and 2C has been proposed mainly for the purpose of increasing the light emitting area as compared with the structure shown in FIG.
[0007]
In any case, in the normal case, the thicker the phosphor layers (28R, 28G, 28B), the higher the light emission luminance at that portion. However, as the thickness increases, the rate of increase in light emission luminance decreases. On the other hand, if the thickness is too large, the light emitting area tends to decrease. Therefore, there is an optimal thickness. In general, the closer to the upper surface of the partition wall 29, the closer to the ultraviolet ray generating portion and the higher the emission luminance. Also in this regard, 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. Further, since the phosphor is relatively expensive, a forming method with less waste is preferable.
In the conventional method of manufacturing the phosphor layers (28R, 28G, 28B), a phosphor layer paste consisting of an organic substance called a vehicle component and a solvent component for forming a paste and a solvent is put between the partition walls 29, and the phosphor layer (28R, 28G, 28B) is required. This is a method in which a solvent portion is evaporated after being attached to a portion, and then baked to remove an organic substance to form the portion.
[0008]
Conventional methods for inserting a predetermined amount of the paste for the phosphor layer between the predetermined partition walls 29 include a screen printing method and a dispenser method. Then, during or after the step of inserting the phosphor layer paste, an operation of attaching the paste to the side surface of the partition wall 29 is performed so as to obtain a desired shape as much as possible.
One example is described in more detail. First, a predetermined amount of a liquid phosphor layer paste is injected into a predetermined portion by a screen printing method or a dispenser method. Allow the layer paste to spread. This operation is continued until the solvent of the paste for the phosphor layer volatilizes and the viscosity of the paste gradually increases and the fluidity disappears, so that the phosphor layers (28R, 28G, 28B) can be obtained. The phosphor layers (28R, 28G, 28B) may be made more uniform by applying micro-vibration, ultrasonic vibration or the like to the substrate in addition to tilting the substrate. Further, in order to make the thickness of the phosphor layers (28R, 28G, 28B) necessary and minimum, the amount of the phosphor layer paste to be injected is adjusted.
[0009]
The problem of the above-mentioned conventional method is that the phosphor layers (28R, 28G, 28B) are not formed on the side surfaces of the partition wall 29 with a desired thickness. As shown in FIG. 3, the thickness of the phosphor layer 28 tended to be smaller than a predetermined thickness at the upper portion of the side surface of the partition wall 29 and larger than the predetermined thickness near the bottom surface. When the thickness of the phosphor layer 28 on the bottom surface is increased, a voltage for generating a discharge between the address discharge starting voltage (address electrode and one electrode of the main electrode pair (41X, 41Y in FIG. 1) on the front plate). ) Has risen, making it difficult to secure a dynamic drive margin required for expressing images. These problems have occurred in any of the partition structures shown in FIGS. 2 (a), 2 (b) and 2 (c). The main reason was that the adhesive strength of the phosphor layer paste to the side surface of the partition wall 29 was insufficient.
[0010]
Regarding this problem, the following countermeasures have been proposed. First, in Japanese Patent Application Laid-Open No. 2000-260330 shown in FIG. 4, after filling each groove with the phosphor layer paste 28a by a screen printing method or a dispenser method, the partition wall 29 is located below the substrate 21. A method of drying the phosphor layer paste 28a in this state is disclosed. That is, it may be easier to insert the phosphor layer paste 28a by a screen printing method or a dispenser method if the viscosity is low. The phosphor layer 28 is formed at the bottom between the two, and hardly adheres to the side surface of the partition wall 29 as shown in FIGS.
As a flow shaping operation of the phosphor layer paste 28a, if the partition 29 is turned downward as shown in FIG. 4, the paste hangs down on the side of the partition 29, and the solvent evaporates with time, and the fluidity decreases. In the end, it takes advantage of the loss of liquidity.
In the above-mentioned Japanese Patent Application Laid-Open No. 2000-260330, the thickness of the desired phosphor layer shape is defined. (1) The thickness of the phosphor layer 28 formed on the side surface of the partition 29 is set at the bottom of the groove between the partitions 29. It is described that the thickness of the formed phosphor layer 28 is １ ／ or more, and further that (2) both have substantially the same thickness. In addition, since the nearer to the top of the partition wall 29 is closer to the plasma as the ultraviolet light source, the illuminance of the ultraviolet light is higher. Therefore, if the thickness of the phosphor layer 28 near the top of the partition wall 29 is increased, the ultraviolet light can be effectively used. Can be said. From this point of view, a method for finely controlling the thickness of the phosphor is required.
[0011]
Further, in the above-mentioned Japanese Patent Application Laid-Open No. 2000-260330, the appropriate thickness of the phosphor layer 28 in the groove between the partition walls 29 is 10 to 20 μm. Further, it is described that the thickness of the phosphor layer 28 is 10 μm or more so as to exhibit a sufficient effect as a reflection layer.
[0012]
Desirable shapes of the phosphor layer are also described in JP-A-11-297213. That is, when the discharge space volume defined by the start and the end of the partition wall on both sides of the substrate and the upper partition wall opening is defined as 100, the actual 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 height, and the thickness of the partition side phosphor layer at a position 20% lower than the partition height from the top of the partition is 10 to 10% of the partition height. It is described as a 25% phosphor screen. Further, 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 dried to reduce the volume. The actual phosphor layer thickness is preferably 10 to 40 μm. It is stated that when the thickness is 10 μm or less, the amount of light emitted to the back surface is large and the luminance is low. In order for the above-mentioned shape to be obtained by this method, there are also shown limitations on the viscosity and fluidity of the paste. However, in this method, it is not sufficient to simply specify the viscosity and fluidity of the paste. In practice, the thickness of the phosphor layer on the side near the top of the partition tends to be 10 μm or less. Also, the thickness of the phosphor layer at the bottom between the partitions tends to be unnecessarily thick.
Regarding this problem, Japanese Patent Application Laid-Open No. 2000-208057 discloses a method for obtaining a phosphor layer having a structure described in Japanese Patent Application Laid-Open No. H11-297213. A method of performing a series of steps of coating 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 for making the phosphor layer have a constant thickness, whether on the side surfaces of the partition walls or at the bottom of the groove between the partition walls. This method is a method of embedding and transferring a phosphor layer paste layer formed in a uniform thickness on another transfer support along irregularities of a partition wall. However, this method becomes more difficult as the height of the groove portion between the partition walls increases and the width decreases. Also. It is difficult with this method to form the phosphor layer in a grid-shaped depression instead of a groove.
[0014]
[Problems to be solved by the invention]
As a method of forming a phosphor layer, the conventional method of inserting a flowable phosphor layer paste between partition walls and performing flow shaping has a problem in that the shape of the phosphor layer paste adhered to the side walls of the partition wall is not satisfactory. It is an object of the present invention to provide a method that can improve the sufficiency and control the shape of a phosphor layer having 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, it is an object of the present invention to provide a forming method which solves a problem of a known method in which it is difficult to reliably obtain a desired shape of a phosphor layer.
[0015]
[Means for Solving the Problems]
According to a first aspect of the present invention, in the method for forming a phosphor layer on a back plate of a plasma display, a fluid layer paste for a phosphor layer is filled into a predetermined space between partitions, and the phosphor layer paste is applied to the side surfaces of the partitions. A method for forming a phosphor layer on a back plate of a plasma display, wherein a shaping operation for attaching the phosphor layer in a preferable shape is performed to eliminate fluidity of a paste for a phosphor layer on a side surface of a partition wall.
[0016]
The invention according to claim 2 is characterized in that the shaping operation of attaching the phosphor layer paste to the side wall of the partition wall is performed while the phosphor layer paste is being charged. This is a method for forming a phosphor layer.
[0017]
The invention according to claim 3 is that the operation of reducing or eliminating the fluidity of the phosphor layer paste formed on the side surface of the partition is performed during or after the shaping operation of the phosphor layer paste. The method for forming a phosphor layer on a back plate of a plasma display according to claim 1 or 2, wherein
[0018]
According to a fourth aspect of the present invention, the flow shaping operation of the phosphor layer paste and the reduction of the fluidity of the phosphor layer paste are performed while observing the shape of the phosphor layer paste inserted. A method for forming a phosphor layer on a back plate of a plasma display according to any one of claims 1 to 3, characterized in that:
[0019]
According to a fifth aspect of the present invention, the color balance of the three fluorescent colors is adjusted by adjusting the adhesion state of the phosphor layer paste for each fluorescent color. Or a method for forming a phosphor layer on a back plate of a plasma display.
[0020]
According to a sixth aspect of the present invention, in the method for flowing and shaping the phosphor layer paste on the side surfaces of the partition walls, a substrate filled with the phosphor layer paste is placed on an inclined rotating plate and rotated at a predetermined inclination angle and rotation speed. The method for forming a phosphor layer on a back plate of a plasma display according to any one of claims 1 to 5, wherein the phosphor layer paste is attached to a side surface of a partition wall.
[0021]
The invention according to claim 7 is that the operation of decreasing or eliminating the fluidity of the phosphor layer formed on the side surface of the partition wall is performed by using any one of radiation curing, cooling curing, and heat curing. A method for forming a phosphor layer on a back plate of a plasma display according to any one of claims 1 to 6.
[0022]
The invention according to claim 8 is characterized in that the substrate is irradiated with radiation in an oblique direction to selectively lower or eliminate the fluidity of the phosphor layer paste on the side surface near the top of the partition wall. 8. A method for forming a phosphor layer on a back plate of a plasma display according to any one of 1 to 7.
[0023]
According to a ninth aspect of the present invention, there is provided a plasma display back plate, wherein a phosphor layer is formed by the method for forming a phosphor layer of the plasma display back plate according to any one of the first to eighth aspects.
[0024]
BEST MODE FOR CARRYING OUT THE INVENTION
In this specification, the term "back plate of plasma display" indicates the "back plate" of the plasma display panel. Naturally, if the "back plate" and the conventionally known "front plate" are bonded together to form the entire panel, it is possible to create the entire panel.
[0025]
Hereinafter, an embodiment of the present invention will be described.
As a well-known shaping operation of flowing the paste for adhering the phosphor layer paste in a preferable shape to the side surface of the partition wall, there are a method of inclining the substrate, and the upper surface of the partition wall as shown in FIG. There are methods and methods combining these methods, which can be used in the present invention. Further, vibration / ultrasonic vibration may be used as auxiliary means.
[0026]
When the flowability 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 a radiation-cured phosphor layer paste, this can be achieved by irradiating a small amount of radiation. In the case of a phosphor layer paste whose viscosity changes with temperature, this can be achieved by lowering the temperature.
[0027]
It is preferable to observe the shape of the phosphor layer paste using a normal microscope or a CCD microscope. In this case, the shape is made easier to observe by devising, for example, oblique illumination. Further, it is convenient to use a three-dimensional image recognition device such as a confocal microscope capable of obtaining information in the depth direction.
[0028]
As a method of inclining the substrate, there is a method of simply inclining right and left when the partition walls are striped. When the partition has a double-girder structure, there is a method of sequentially tilting in four directions. As a more preferable method, as shown in FIG. 6, a method of rotating the glass substrate 21 with the glass substrate 21 placed on an inclined rotating table 51. There is. In this case, the state of attachment to the partition wall 29 can be changed by changing the inclination angle and the rotation speed. This method can also be used for the stripe-shaped partition wall 29. By changing the rotation speed within one rotation, it is possible to adhere the ink to the surrounding partition walls 29 unevenly.
[0029]
When using a paste of which the fluidity is reduced / disappears by irradiation of radiation, as a method of lowering or eliminating the fluidity of the phosphor layer paste at a desired location, a method of irradiating radiation from an oblique direction is used. There is. This method will be described later in detail. Another method is to use radiation with a short working distance. For example, in electron beam irradiation, the working distance is greatly changed by the accelerating voltage, and is also absorbed by nitrogen or the like between the irradiation device and the object to be irradiated, and the curing effect is reduced. Can be eliminated. In addition, there is a method using a short wavelength ultraviolet ray. Also in this case, since the air is absorbed by the intermediate air, the working distance can be adjusted.
[0030]
Further, when a method of causing the phosphor layer paste to flow down the side surfaces of the partition walls by using a screen printing method as in JP-A-2000-208057, radiation is applied so that only the side surface portions of the partition walls are cured. The phosphor layer paste can be attached to the side wall of the partition wall by using a method of irradiating from an oblique direction.
[0031]
Generally, it is necessary that the amount of the paste to be added is such that the phosphor layer can be formed to a predetermined thickness. When the amount deviates from the predetermined amount, the emission luminance deviates, and the balance of the three colors deteriorates. This phenomenon occurs partially or entirely. When one gap, that is, the partition is striped, it is one groove, and when the partition is matrix (cross-girder), it is one square (bowl) -shaped part. It is necessary to make the amount of the phosphor layer paste incorporated as uniform as possible.
However, in the method of the present invention, which is one of the methods, in which the shaping operation is performed by inserting the fluid phosphor paste, 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 squares between the partition walls.
However, according to the method of the present invention, since the cross-sectional shape of the phosphor layer can be made quite accurately to a desired shape, the emission luminance can be adjusted as follows. Therefore, even if the amount of the phosphor layer paste to be inserted slightly deviates from the predetermined amount, the emission luminance can be set to the predetermined value. The method makes use of the fact that the emission luminance is high near the top of the partition and low at the bottom. That is, when a phosphor layer paste larger than a predetermined amount is contained, the phosphor layer near the top of the partition is thinned. On the other hand, when the amount of the paste for the phosphor layer is smaller than the predetermined amount, the thickness of the phosphor layer on the side surface near the top of the partition wall is increased from the predetermined value. It is an advantage of the present invention that such shaping control is possible.
[0032]
The shaping operation is performed for phosphors of three colors separately in principle. However, it is also possible to shape the three colors simultaneously by making the paste viscosities of the three colors the same. Even when the intervals between the partition walls are unequal, three colors can be simultaneously shaped 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 portion that does not need to be irradiated is not irradiated using a mask.
[0033]
As the paste characterized by changing from a fluid state to a non-fluid state by irradiating radiation, basically, a paste known as a photosensitive phosphor layer paste can be used. .
Radiation that acts to reduce or eliminate the fluidity of the phosphor layer paste includes visible light, ultraviolet light, and electron beams. In most cases, pastes that cure with visible or ultraviolet light can be cured with electron beams. In addition, in the case of electron beam curing, a polymerization initiator is not needed in most cases.
[0034]
The photosensitive phosphor layer paste comprises at least a phosphor and a photosensitive component. Examples of known pastes include JP-A-10-90889, JP-A-10-283927, JP-A-11-65086, and JP-A-11-65086. 11-297213 and JP-A-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 state of fluidity to make the state substantially non-fluid. On the other hand, in the above-mentioned two known materials and other ordinary methods of use, the coating is applied to a desired place, dried, then exposed and cured. “Curing” in this case involves irradiating the already solid state with light to reduce the solubility in a solvent or improve the sandblast resistance.
[0035]
In the case of radiation curing, depending on the type of polymerization initiator, oxygen damage may occur and the surface may not be cured. However, most compositions cure to the extent that fluidity is lost. 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, since oxygen damage occurs, the electron beam irradiation chamber is usually replaced with nitrogen. However, even if oxygen damage occurs, the composition is cured to the extent that the fluidity is lost, so that nitrogen replacement is unnecessary.
[0036]
The above paste generally comprises at least a polyfunctional or bifunctional monomer, oligomer, or polymer and a photoreaction initiator used in a photosensitive paste for firing. Further, it may contain a polymer or a solvent for adjusting fluidity, or a storage stabilizer. Specifically, acrylic-based materials are actually preferred as polyfunctional or bifunctional monomers, oligomers, and polymers.
[0037]
It is sufficient that the fluidity is eliminated by irradiating the radiation, and there is no need to cure, so that the amount of the photopolymerization initiator can be reduced as compared with the photocurable paste. Further, the amount of the monofunctional polymer or the bifunctional polymer / oligomer may be increased. However, it is generally preferable to increase the content of the inorganic component as much as possible. Further, in order to prevent the phosphor from settling in the paste, it is better that the viscosity of the paste is relatively high.
To adjust the viscosity, a solvent, a polymer or a dispersant is added. The appropriate viscosity depends on the method of filling between the ribs and the method of spreading on the side of the partition. Very high flowability makes it difficult to fill, for example, by screen printing, but makes it easier to dispense with a dispenser. Also, when the substrate is spread on the side surface of the partition, the substrate can be easily spread only by tilting the substrate. However, in some cases, the phosphor and the photosensitive component are easily separated, or it is necessary to fill a large amount.
[0038]
FIG. 7 shows one means for irradiating light obliquely to adjust the fluidity of the phosphor layer paste 28 in a portion (region) near the top of the partition wall. In this case, the adjacent partition wall 29 functions as a light-shielding material, so that unnecessary portions are not irradiated. Further, in the case of FIG. 7, the light is irradiated while the substrate 21 is tilted to eliminate the fluidity. However, the light may be irradiated after returning to the horizontal state.
More specifically, for example, a phosphor layer paste is attached and fixed to the side surface of the partition wall 29. That is, (1) the phosphor layer paste is adhered to one side surface at an angle in a certain direction. Then, return to horizontal and observe that the phosphor layer paste on the partition wall 29 falls down. When the thickness becomes just right, the phosphor layer paste on the partition wall 29 is irradiated by diagonally irradiating light. Eliminate liquidity. {Circle around (2)} Next, the substrate 21 is tilted to the opposite side to adhere to the side surface of the partition wall 29 on the opposite side, and the substrate 21 is returned to a horizontal position. lose. {Circle around (3)} By irradiating the light vertically, the fluidity of the phosphor layer paste at the bottom between the partition walls 29 is eliminated. However, in practice, when steps (1), (2) and (3) are performed in completely separate steps, a step occurs at the boundary of the portion where fluidity is lost, so that the irradiation angle is continuously changed during light irradiation. Or irradiating light while continuously changing the inclination of the substrate, or continuously adjusting the intensity of light.
[0039]
As another method, a method in which the substrate 21 is inclined and the phosphor layer paste is caused to flow to the side surface of the partition wall 29, and in that state, the fluidity of the phosphor layer paste at a required portion (the side surface near the top of the partition wall 29) is eliminated. There is. In this method, if the viscosity of the phosphor layer paste is too low, the phosphor layer paste layer near the top is thin or almost non-existent, as shown in FIGS. 5 (a) and 5 (b). However, as the viscosity of the phosphor layer paste increases, the portion near the top also becomes thicker. Therefore, the viscosity of the phosphor layer paste is adjusted so as to obtain this state. The method of adjusting the viscosity is radiation irradiation in the radiation polymerization type, and temperature adjustment in the heating fluidization type.
[0040]
In addition, in the case where the fluid wavelength of the phosphor layer paste is eliminated only in a portion near the top of the partition wall 29, short-wavelength ultraviolet light having a large absorption in the air is used. For example, an excimer laser of 147 nm of xenon and 193 nm of ArF is used. Since the height of the partition 29 is 100 μm to 200 μm, only the photosensitive phosphor layer paste near the top of the partition 29 loses fluidity.
[0041]
In a cooling non-fluidized paste for a phosphor layer, in the absence of a solvent, it is necessary that the paste does not flow but remains solid even when the temperature is increased during firing. The vehicle material for that purpose needs to be a material that does not melt when heated and sublimates or decomposes. As an actual material, there is a resin used for the paste for firing, for example, a cellulose resin or an acrylic resin. When this type of paste is used, it is necessary to evaporate the solvent in a state where a required shape is obtained by cooling, and a method of reducing the pressure other than leaving the paste is effective. Cellulose-based resins are most commonly used in firing pastes. 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 of utilizing a temperature difference between the base of the substrate and the upper surface of the partition. That is, the method is such that the atmosphere between the heated partition walls of the substrate is adjusted such that the paste has no fluidity at a temperature near the upper surface of the partition walls, although the paste has fluidity. Place on a heating plate, fill the heated paste between the partitions of the heated substrate with all three colors (by three screen printings), then tilt the substrate and along the sides of the partitions for the phosphor layer Allow the paste to flow. Here, as the paste approaches the top of the partition, the temperature decreases, the fluidity decreases, and the fluid 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. When the temperature of the substrate is lowered while the inclination of the substrate is gradually reduced, the fluidity of the paste is sequentially lost, and a desired shape can be obtained. Next, the solvent of the paste is vacuum dried or left to dry. Then, it becomes a state where it does not fluidize even when heated.
[0043]
As the solvent, there is a method of combining a good solvent and a poor solvent. As both solvents evaporate, they become gelled and lose fluidity. In addition, 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, heating drying, and natural drying. However, if the solvent is removed too quickly, cracks may occur. In the case of a cooling non-fluidizing type, the solvent is removed in a cooled state. In that case, vacuum (reduced pressure) drying is preferable.
[0044]
Further, as the phosphor layer paste, a paste that is cured by adding (mixing) a curing agent can also be used. As a resin suitable for this, a resin that disappears when fired must be used, and an acrylic resin can be used.
[0045]
As the phosphor layer paste, a paste that cures when heated can also be used. The heat-curing type does not cure (substantially loses fluidity) in a short time (instantaneous to several seconds) than radiation curing, but it cures in about 10 seconds with far-infrared heating. Yes, and can be used as appropriate.
【The invention's effect】
The phosphor layer of the back plate of the plasma display can be formed on the side surface of the partition wall at a desired thickness, and the efficiency of using the phosphor for light emission can be increased. Luminous efficiency can also be increased. Further, it becomes possible to form a phosphor layer having a shape that was difficult with the conventional method, it becomes possible to adjust the emission luminance, and it is easier to improve the color balance than before.
[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 view showing an example of the shape of a partition.
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 conventional drying method when forming a phosphor layer of a PDP.
FIG. 5 is an explanatory view showing a state in which a phosphor layer paste is inserted between partition walls by a conventional method.
FIG. 6 is an explanatory view showing a method of forming a phosphor layer on a partition wall of a grid-like partition wall (a hole-shaped light emitting portion).
FIG. 7 is an explanatory view showing a method of selectively lowering the fluidity of a phosphor layer paste near the upper surface of a partition wall by irradiating radiation from an oblique direction.
[Explanation of symbols]
1 .... PDP with AC type three-electrode surface discharge structure
11 Front glass substrate
17: Dielectric layer
18 ... Protective layer
21 ... Glass substrate on the back side
22: Underlayer
24 ... dielectric layer
28, 28R, 28G, 28B ... phosphor layer
29, 29b ... partition walls
30 ... Discharge space
41 ... Transparent conductive film
42 ... metal film (bus electrode)
51 ... turntable
A: Address electrode
D: Flow direction of the phosphor layer paste
H ... Radiation
L ... line
X, Y: Sustain electrode

Claims (9)

In the method for forming a phosphor layer on a back panel of a plasma display, a shaping operation is performed in which a paste for a phosphor layer having fluidity is filled in a predetermined space between partitions, and the paste for a phosphor layer is adhered to a side surface of the partition in a preferable shape. And removing the fluidity of the phosphor layer paste on the side surfaces of the partition walls. 2. The method for forming a phosphor layer on a rear plate of a plasma display according to claim 1, 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 charged. The method according to claim 1, wherein the operation of reducing or eliminating the fluidity of the phosphor layer paste formed on the side surface of the partition is performed during or after the shaping operation of the phosphor layer paste. A method for forming a phosphor layer on a back plate of a plasma display as described above. 4. The method according to claim 1, wherein a flow shaping operation of the phosphor layer paste and a decrease in the fluidity of the phosphor layer paste are performed while observing the shape of the phosphor layer paste inserted. A method for forming a phosphor layer on a back plate of a plasma display according to any one of the above. 5. 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. A method for forming a phosphor layer. The method of flowing and shaping the phosphor layer paste on the side surfaces of the partition walls is such that a substrate filled with the phosphor layer paste is placed on an inclined rotating plate, and the substrate is rotated at a predetermined inclination angle and rotation speed, and the fluorescent material pastes on the side surfaces of the partition walls. The method for forming a phosphor layer on a rear plate of a plasma display according to any one of claims 1 to 5, wherein the method is a method of attaching a body layer paste. 7. The method according to claim 1, wherein the operation of decreasing or eliminating the fluidity of the phosphor layer formed on the side surface of the partition is performed by using any one of radiation curing, cooling curing, and heat curing. A method for forming a phosphor layer on a back plate of a plasma display according to any one of the above. 8. The method according to claim 1, wherein the substrate is irradiated with radiation from an oblique direction to selectively lower or eliminate the fluidity of the phosphor layer paste on the side surface near the top of the partition wall. A method for forming a phosphor layer on a back plate of a plasma display. A plasma display back plate, wherein a phosphor layer is formed by the method for forming a phosphor layer of a plasma display back plate according to any one of claims 1 to 8.

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