JP3656387B2 - Fluorescent substance forming method and apparatus for color display PDP - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method of manufacturing a color plasma display panel used as a wall-mounted television or an information display, and an apparatus for manufacturing the same.
[0002]
[Prior art]
The back plate of a plasma display panel (PDP), an elongated striped recessed portion is a number features <br/>. It is necessary to produce phosphor films of three colors of red, blue, and green for each concave portion. As a method for forming the phosphor, a screen printing method is often used because it can be easily performed at low cost.
[0003]
This method is a method in which a phosphor film in which phosphor particles are dispersed in a solvent is applied to the entire back panel having recesses, and then dried and cured to form a phosphor film. This is a method of repeating the same work with matching patterns.
[0004]
However, in the screen printing method, the mask is mechanically deformed by the weight of the squeegee and the phosphor liquid, and as a result, it is very difficult to form a pattern with high accuracy.
[0005]
In addition, as a method that can be manufactured with high accuracy, there is a method using photography, but in this case, many steps such as coating, exposure, development, and drying are required, resulting in high cost.
[0006]
In addition, as a method that can be manufactured with high accuracy, there is a method in which a phosphor film made of a phosphor and a high-viscosity solvent is pasted on a substrate, pressed into a concave portion, and unnecessary portions are removed by a method such as exposure. The amount of the phosphor is required to be three times or more the required amount, resulting in high cost.
[0007]
[Problems to be solved by the invention]
In the PDP, in order to perform light emission of each recess satisfactorily, it is necessary to cause the discharge generated in the recess to act efficiently on the phosphor and to efficiently extract the light generated in the phosphor to the outside. For this reason, it is necessary that the phosphor film is arranged in a uniform and uniform thickness with a certain thickness (20 μm ± 5 μm) inside the recess. A dome shape or a parabolic shape is preferred. Moreover, if the film thickness is not the same for all the substrates, unevenness occurs. Naturally, it is not preferable that color mixture exists. In addition, if a fluorescent material is adhered between the concave portions, the contrast is lowered, so that good screen quality cannot be expected.
[0008]
However, the whole of the above-described substrate, the method of drying curing the fluorescent body fluid was applied by printing methods, it can not be sufficiently satisfied the requirements as described above. Filling the inside of the recess with a large amount of phosphor liquid surely forms the phosphor film on the entire inner surface of the recess, and the film thickness to be formed becomes too thick, and the possibility that the phosphor film is formed beyond the recess is high. . When the amount of the phosphor liquid is reduced, the phosphor liquid is supplied only near the bottom of the recess, and the phosphor film is formed only on that portion.
[0009]
Furthermore, before the phosphor liquid is applied and dried, there is a problem that the phosphor in the liquid settles and adheres only to the bottom of the recess.
[0010]
In order to solve such a problem, a method of supplying a phosphor to fill the recess completely to form a thick phosphor film, and then polishing and removing a part of the phosphor film to a desired film thickness is also considered. However, there are problems such as polishing cost, phosphor cost, and difficulty in controlling polishing.
[0011]
There is also a method of sticking the phosphor film shown above on the substrate, pressing it into the recess, and removing unnecessary parts by a method such as exposure, but the amount of the phosphor is required to be at least three times the required amount. Become expensive.
[0012]
As a problem of the substrate itself, in particular, in the case of a substrate manufactured by a printing method, baking is performed at around 500 degrees in order to skip the solvent used in printing. For this reason, the substrate glass is distorted, and there are many cases in which irregularities have portions that lack regularity (projection spacing, recess spacing). In this case, since the discharge interval of the nozzle does not coincide with the rib interval, it cannot be simply applied. In addition, substrates produced by other methods are also distorted and strained due to heat treatment.
[0013]
[Means for Solving the Problems]
Straight recess formed in plurality on a surface of a substrate, discharging the fluorescent fluid from the de I Spencer A method of forming a phosphor film in the heat treatment, the volume of the linear concave portion of the discharge amount from the dispenser the amount of the filling rate is 105% from 65% with respect to, between the substrate and the dispenser, selectively a mask open mouth is formed is positioned parallel said substrate substantially, said through the mask and the substrate and the mask while discharging the fluorescent fluid from the dispenser using the method of relatively moving in the linear direction of the linear concave portion relative to the dispenser.
[0014]
Straight recess formed in plural on the surface of the base plate, ejecting the fluorescent fluid from the de I Spencer A method of forming a phosphor film by thermal processing, the linear recess the discharge rate from the dispenser the filling rate to the volume is in an amount to achieve 105% from 65%, the dispenser was while discharging the fluorescent body fluid along the linear direction of the linear concave portion relatively moving the substrate and the dispenser, the straight line direction temporarily stop Ru how the use of the discharge on the move.
[0015]
Dispenser, the discharge port comprises a plurality of dispensers disposed substantially linearly, a method of simultaneously discharging different color from their respective of said plurality of dispensers.
[0016]
Detecting the distance in the direction perpendicular in the linear direction and the substrate surface of the straight line recess, dispenser, the discharge port comprises a plurality of dispensers disposed substantially linearly, so the previous SL plurality of dispensers times translocated , a method to adjust the pitch of the discharge port of the dispenser during the detected interval.
[0017]
Except for the plane including the discharge port of the de I Spencer all aspects of fluorescent fluid is in contact, at an angle of the normal direction vector and the gravity direction vector of the side of the surface in contact with liquid, the smaller angle 0 ° A method that is up to 135 degrees is used.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
(Embodiment 1)
FIG. 1 shows Embodiment 1 of the present invention. 20 is a dispenser, 22 is a phosphor liquid supply system, 30 is a phosphor liquid, 40 is a mask, and 10 is a substrate.
[0019]
The substrate 10 is made of a glass material, and concave portions made of different substances are formed in a line shape on the substrate. The dispenser 20 fills the phosphor liquid in the portion corresponding to the opening of the substrate 10 by moving at high speed along the opening at about 0.5 to 2 m / sec while discharging the liquid. As for the size of the discharge port of the dispenser 20, since a phosphor is inserted into a groove of 0.15 mm, a circular aperture having a smaller diameter is required. The dispenser 20 may be fixed and the base on which the substrate 10 is set may be reciprocated by a motor integrally with the mask. The discharge amount is controlled so that 90% of the volume of the recess is filled with the phosphor liquid. It is desirable that the liquid discharged from the dispenser 20 is always continuously discharged.
[0020]
As the mask material, a metal plate of aluminum and SUS316 with a thickness of 0.5 mm was used. Thick thickness of the mask, when the distance between the mask and the substrate are close, accumulate bounce fluorescent fluid in the portion of the thickness by re-dropped, or contain fluorescent fluid to another part, the color no Ragaokoru . A phosphor liquid having a viscosity of 30 to 100 cps and a low viscosity is used.
[0021]
The configuration of the opening and the non-opening of the mask can be freely selected according to the uneven pattern of the substrate.
[0022]
The distance between the discharge port of the dispenser 20 and the substrate is determined by the state of spreading and bending of the phosphor liquid from the dispenser 20. First, consider the spreading state. In the case of the present invention, unlike the normal case, the discharge port is as small as about 0.1 mm in diameter, the surface area per discharge cross-sectional area is large, and the discharge speed is also high. In addition, since a highly concentrated slurry is used, it behaves quite differently from normal water. That is, the ejection state as shown in FIG. As shown in FIG. 2, the liquid discharged at the point A, the initial speed V1 , the cross-sectional area S1, and the discharge amount Q1 (Q1 = V1 × S1) is the point B, the speed V2, the cross-sectional area S2, and the discharge amount Q2 (Q2). = V2 × S2). Since V2 becomes larger than V1 due to free fall and the discharge amount is constant (Q1 = Q2), S2 becomes inevitably smaller. Further, as the free fall distance advances, the speed increases. Finally, at the point C, the outer portion becomes fine particles and scatters. In order to apply the phosphor liquid to the concave portion, the discharge cross-sectional area must be smaller than the groove width of the concave portion, and it is necessary to be connected linearly. The spread state is greatly influenced by the surface tension, viscosity, and initial speed of the liquid. The initial speed is limited in range from the stability (clogging) of the dispenser, and the surface tension is also limited by the solvent. Also, the viscosity of the liquid is limited because it is discharged from the discharge port of about 0.1 mm. Therefore, the phosphor liquid that can be used in this method is limited in terms of characteristics. FIG. 3 shows values obtained by experiments on the relationship between the discharge sectional area of the liquid used this time and the distance from the dispenser. From where it exceeds 50 mm, it becomes granular and scattering begins. Therefore, in order to perform a stable coating in a straight line, the coating cannot be performed unless the distance h between the dispenser discharge port and the substrate is 50 mm or less.
[0023]
Next, consider the rolling state. As shown in FIG. 4A, the liquid discharge 30 from the dispenser bends at a minute angle with respect to the perpendicular 31. The reason for the bending is due to the processing straightness accuracy of the discharge port, lack of objectability, scratches, and nonuniformity of the surface state of the discharge port. In particular, in this case, since the viscosity of the liquid is high and the slurry liquid is high in concentration, even if the liquid is very small in the vicinity of the discharge port, the liquid spreads unevenly, the surface tension balance is lost, and the discharge is easily bent. In the case of discharge port processing accuracy, lack of objectability, scratches, etc., it always bends in the same direction. On the other hand, in the case of non-uniformity in the surface state of the discharge port, it changes with discharge. The bending state was examined with a dispenser when the former processing accuracy was completely guaranteed. The result is shown in FIG. In FIG. 5, the range of the bend in which the 99% reproducibility probability can be guaranteed is ± 0.05 degrees, and it is necessary to always expect an angular deviation of this degree of straight travel.
[0024]
The distance h between the recess and the dispenser is determined from the above two constraints. From the state of the discharge cross-sectional area, it is essential to use 50 mm or less. On the other hand, when the distance h between the concave portion and the dispenser is 60 mm from the bending of the discharge, the distance of the bending by the discharge is L1 = 0.052 mm. As shown in FIG. 4B, the width of the half of the groove of the recess is L2 = 0.075 mm, which is 0.052 mm from the center, and the difference 0.023 mm is the maximum allowable radius of the discharge liquid. . This diameter is allowed up to 0.046 mm. When discharged from the current discharge population 1 mm, at a distance of 60 mm, the diameter of the discharge, is 0.045 mm, it can be completely discharged in the recess. Furthermore, if the distance between the dispenser and the recess is reduced to 60 mm or less, the discharge diameter allowed from the discharge bend increases and all the discharge can be inserted into the recess. From the above two common ranges, it is essential that the distance between the dispenser discharge port and the substrate is 50 mm or less.
[0025]
As an application of the mask, as shown in FIG. 6A and its sectional view 6B, a mask 40 having the same size as the whole substrate is produced, and an opening corresponding to the concave portion is opened in the mask 40. It is also conceivable to discharge the phosphor liquid from above. In this way, the phosphor can be selectively applied only to the concave portion without attaching the phosphor to the convex portion. The thickness of the mask 40 is preferably about 1 to 0.5 mm. If the thickness is large, the discharge is bent and the phosphor liquid is applied to the inner portion of the mask 40 and is transmitted to the back surface (substrate side) of the mask 40, and is on the convex portion.
[0026]
(Embodiment 2)
The present invention will be described with reference to FIGS. FIG. 7 shows a cross section of a conventional dispenser 20 and a cross section of the substrate 10. In addition, the liquid and the like are the same as those in the first embodiment. As can be seen from FIG. 7, the phosphor liquid is different from water or alcohol, has a high viscosity, and has a low surface tension. Therefore, it is easy to generate the wetting and spreading 50 near the discharge port, and as a result, the discharge is easily bent. Unexpected Re When spread 50 generates the discharge bends in that direction. If the discharge port is wiped off with a cloth or the like, it is discharged straight, but the discharge tends to bend due to changes over time and long-term stability. In the present invention, as shown in FIG. 8, the liquid guide 90 is provided to straighten the discharge. The guide 90 is located near the center of the discharge port of the dispenser 29, and protrudes from the discharge surface and is positioned linearly. It is drawn to this guide 90 and falls straight down. The guide 90 can be made of a thin wire such as a piano wire, a horse, a pig, a goat hair, or nylon. In the case of gentle horses, pigs, goat hair, and nylon, the phosphor liquid can be reliably discharged into the recesses by discharging the phosphor liquid while being in direct contact with the bottom of the recess. Furthermore, even if the liquid discharge ON / OFF operation is repeated, the discharge port of the dispenser 20 is not soiled by the liquid, and is stable. Further, in this embodiment, the liquid guide is discharged from the center of the discharge port, but by providing the protruding portion 91 in which a part of the discharge port protrudes from the discharge surface, the same effect as above can be obtained. (FIG. 8C).
[0027]
(Embodiment 3)
The third embodiment will be described with reference to FIGS. The dispenser 20 is, for example, a dispenser having three discharge ports. In addition, the liquid and the like are the same as those in the first embodiment. FIG. 9 is a cross-section of the conventional dispenser after discharging the phosphor. As time passes, the phosphor 110 settles around the discharge port, and the discharge port is clogged or the discharge line is turned. In particular, between the discharge port and the side surface of the dispenser, the flow rate is slow and the phosphor is likely to precipitate. Compared to that, the flow rate between the discharge ports is high and the sedimentation is not easy. As a method for eliminating these precipitates, sectional views 10 and 11 of the head of the present invention are shown. In FIG. 10, a set of ceramic piezoelectric elements 120 is embedded in the head, and ultrasonic waves can be generated. When applying the phosphor liquid to the substrate, it is desirable not to generate ultrasonic waves in order to maintain ejection stability. Or you may generate a low output ultrasonic wave continuously. Due to this ultrasonic wave, the phosphor precipitate 110 is not generated, and the discharge line is stabilized over a long period of time. Also, it can be combined with ON / OFF of discharge. That is, when it is OFF, an ultrasonic wave is generated to prevent the phosphor from being precipitated, and when it is ON, no ultrasonic wave is generated. In FIG. 11A, a steep slope is provided on the entire surface of the dispenser so that the phosphor does not settle. The surface inclination angle was defined as the smaller angle formed by the normal of the surface in contact with the liquid and the gravitational direction (FIG. 11B). The limit slope angle that suppresses sedimentation was determined by the following experiment. That is, the phosphor solution was dropped on a metal plate with the tilt angle changed arbitrarily, and the behavior of the phosphor solution on the metal plate was observed. As a result, in the case of θ = 0 to 135 degrees, it was confirmed that the phosphor liquid did not remain and flowed downward on the metal plate without precipitation.
[0028]
(Embodiment 4)
A fourth embodiment will be described with reference to FIGS. In FIG. 12A, the dispenser 20 is a dispenser having three discharge ports. In addition, the liquid and the like are the same as those in the first embodiment. 140 is a pump for supplying a phosphor solution, 142 is a phosphor solution tank, 143 is a pump control unit, 144 is a substrate moving motor control unit, 145 is a thermocouple, 146 is a belt, 147 is a motor, 148 is a belt 146 and a substrate It is a fastening bracket that mechanically fastens. The temperature of the phosphor liquid is measured with a thermocouple of 145, the discharge amount is estimated from the graph of FIG. 12B measured in advance, and the substrate speed at which a certain amount of phosphor liquid is filled in the recess is obtained. By changing the substrate moving speed in the motor control unit 144, the change in the discharge amount due to the temperature of the liquid is corrected, and the phosphor liquid is uniformly discharged into the recess. The viscosity of the phosphor liquid varies greatly depending on the temperature, which is the main cause of the change in ejection. For this reason, the ejection changes greatly due to the change in the liquid temperature. Further, the substrate speed is changed by transmitting the rotation of the motor 147 attached to the lower portion of the substrate to the substrate through the belt 146, and the rotation speed of the motor 147 can be freely controlled by the controller 144. According to the present invention, the change in the discharge amount due to the change in the liquid temperature is compensated with the substrate speed that is easy to control with high accuracy, and the filling rate into the concave portion is made constant to produce a uniform phosphor film. That is, when the temperature rises by 2 ° C., the substantial viscosity of the phosphor liquid changes by about 10%, and the discharge amount increases. At this time, if the substrate speed is increased by an amount corresponding to the increase in the discharge amount, and the temperature at which the concave portion can be filled with a certain amount of phosphor as a result is lowered, then the opposite should be done. Become.
[0029]
The pump may be a displacement-type gear pump, and the liquid level may be pushed out by air pressure or the like.
[0030]
Alternatively, a flow meter may be set between the supply system 22 and the pump 141 to directly detect the flow rate and change the substrate moving speed.
[0031]
(Embodiment 5)
Embodiment 5 will be described with reference to FIGS. 152 is a displacement meter, 153 is a device with a head rotation angle, 20 is a dispenser for three discharges, 156 is a displacement meter movement motor, 155 is a head movement motor, 144 is a board movement motor control panel, 154 is It is a controller. First, the displacement meter 152 measures the unevenness in the pitch direction of the concave line, and based on the data, determines the angle at which the dispenser 20 is rotated and the distance (translation) to move in the pitch direction of the concave line. FIG. 13B shows the measurement data of the laser displacement meter. The distance between the concave portions of the data is read, and the distance (translation) for moving the head is determined. The dispenser 20 used was a three-discharge dispenser. In order to increase the resolution of correction, it is better that the number of dispensers is small. A rotation angle is given to the dispenser so that the interval between the three ejection openings matches the interval between the recesses. FIG. 13C shows a schematic diagram of the interval between the recesses and the rotation of the dispenser 20 . Since the discharge interval of the dispenser is determined, the rotation angle is calculated from the interval of the recesses.
[0032]
The operation is shown. The displacement meter 152 is moved from the end of the recess to the end in the pitch direction of the recess line, and the rotation angle of the dispenser 20 and the movement distance of the dispenser are determined and executed from the interval of the unevenness. While discharging the phosphor liquid from the dispenser 20, the lower substrate is moved to discharge the phosphor liquid into the recess along the recess line.
[0033]
If the irregularity of the substrate is distorted and is partially unsatisfactory, the phosphor solution can be applied by the following method. Similarly to the above, the displacement meter 152 is moved in the pitch direction of the recess lines from end to end of the recesses, and the interval between the recesses is read over the entire substrate and recorded, whereby the recess line group is distorted. And read the pitch shift over the entire surface of the substrate. Based on this data, while discharging the fluorescent fluid from the dispenser 20, when applied to a substrate, the heads in the motor 155 in the pitch direction of the concave lines, while a small distance movement, corresponding to irregularities. In this way, the phosphor liquid can be accurately discharged into the concave portion even if the uneven portion is partially distorted in the substrate. In the case where a part of the substrate is distorted, the number of the substrates is three this time. However, if the number of the substrates increases, the distance between the recesses does not match. The smaller the number, the better the position.
[0034]
Moreover, if the rotation angle of the dispenser is combined with translation, a phosphor can be formed in any irregular recess.
[0035]
(Embodiment 6)
Embodiment 6 will be described with reference to FIGS. 14 (a), 14 (b), and 14 (c). In the conventional printing method, only a high-viscosity liquid of about tens of thousands cps can be used due to blurring and back-faced movement. Therefore, the recess filling ratio of the phosphor liquid is low, and as shown in the substrate cross-sectional view of FIG. 14A, the phosphor film can be formed only on the bottom. Therefore, the brightness was low. In this invention, as shown in FIG. 14 (b), the phosphor liquid having a filling rate of 65% to 105% of the volume of the concave portion is discharged and the solvent is evaporated, whereby the concave portion as shown in FIG. 14 (c) is obtained. A phosphor film is attached to the entire surface. Thereby, the surface area was improved and the luminance was increased by about 50% or more.
[0036]
The phosphor liquid used in the present invention has a viscosity of 30 to 100 cps. In the case of the concave portion of FIG. 14C, L3 = 0.100 mm, L4 = 0.150 mm, the cross-sectional area is 0.02355 mm2, and when 100% is filled and the solvent is evaporated, the phosphor film is homogeneous in the concave portion. Attached and averaged about 32 microns. The specs of the phosphor film are 25 μm ± 5 μm, and the physical properties of the liquid are the same. A substantially directly proportional relationship is established between the filling amount and the finally formed average phosphor film thickness. Therefore, when the discharge stability (± 1%) and the discharge amount between holes (± 1%) are taken into consideration, a filling rate of 65% or more is required.
[0037]
In addition, since the maximum filling rate absorbs the solvent, the maximum filling rate does not overflow from the recess even if it is set to 105%.
[0038]
【The invention's effect】
As described above, the method of the present invention, the inner surface of the plurality of linear recesses having on a surface of the substrate, the fluorescent fluid in which the phosphor particles are dispersed in a liquid medium, discharged from de I Spencer heat treatment In the method of forming a phosphor film, pattern formation is performed with no color mixing, with high accuracy, and with the minimum necessary amount of coating liquid used.
[0039]
This method makes it possible to efficiently manufacture a high-definition plasma display panel.
[Brief description of the drawings]
FIG. 1 is a diagram showing an example of an embodiment of the present invention. FIG. 2 is a schematic diagram of phosphor liquid discharge according to the present invention. FIG. 3 is a diagram showing a relationship between a distance from a dispenser and a discharge cross-sectional area. ) Is a diagram showing the bending angle θ of the discharge from the dispenser. (B) is an explanatory diagram showing the bending and misalignment of the liquid. FIG. 5 is a distribution diagram of the bending angle θ obtained in the experiment. FIG. 7B is a cross-sectional view of FIG. 6A. FIG. 7 is a diagram showing a discharge state of a conventional dispenser. FIG. 8A is a diagram showing another embodiment of the present invention. (B) Perspective view of the discharge port of FIG. 8-a (c) View showing another embodiment [FIG. 9] Cross-sectional view of a conventional dispenser [FIG. 10] Cross-sectional view of the nozzle of the present invention [FIG. ) Is a cross-sectional view of the dispenser of the present invention. (B) is a diagram showing the definition of the angle. [FIG. 12] (a) is another embodiment of the present invention. FIG. 13B is a diagram showing the relationship between temperature and discharge amount. FIG. 13A is a diagram showing another embodiment of the present invention. FIG. 13B is a diagram showing measurement results of unevenness. FIG. 14 is a diagram showing the relationship between the rotation angle of the dispenser and the concavo-convex portion. FIG. 14 (a) A diagram showing the shape of a conventional phosphor film. (B) A schematic diagram showing a filling state of the phosphor liquid of the present invention. Schematic diagram showing the shape of the phosphor [Explanation of symbols]
10 substrate 20 dispenser 22 fluorescent fluid supply system 30 fluorescent fluid 31 perpendicular 40 mask 50 Nu Re spread 90 liquid guide

Claims (5)

  A method in which a phosphor liquid is discharged from a dispenser into a plurality of linear recesses formed on the surface of a substrate, and a phosphor film is formed by heat treatment, wherein a discharge rate from the dispenser is a filling rate with respect to a volume of the linear recesses A mask having an opening selectively formed between the substrate and the dispenser is positioned substantially parallel to the substrate, and the phosphor liquid is removed from the dispenser through the mask. A method of forming a phosphor of a color display PDP, wherein the substrate and the mask are moved relative to the dispenser in a linear direction of the linear recess while discharging the liquid.   A method in which a phosphor liquid is discharged from a dispenser into a plurality of linear recesses formed on the surface of a substrate, and a phosphor film is formed by heat treatment, wherein a discharge rate from the dispenser is a filling rate with respect to a volume of the linear recesses The amount of the liquid crystal is changed from 65% to 105%, and the substrate and the dispenser are relatively moved along the linear direction of the linear recess while discharging the phosphor liquid with the dispenser, and discharged while moving in the linear direction. A method for forming a phosphor of a color display PDP, characterized by temporarily stopping the process.   The method for forming a phosphor of a color display PDP according to claim 1, wherein the dispenser includes a plurality of dispensers having discharge ports arranged substantially linearly.   4. The method for forming a phosphor of a color display PDP according to claim 3, wherein different colors are simultaneously discharged from each of the plurality of dispensers. The interval between the linear direction of the linear recesses and the direction orthogonal to the substrate surface is detected, and the plurality of dispensers are rotated so that the discharge port arrangement directions of the dispensers are inclined with respect to the linear direction of the linear recesses. The method for forming a phosphor of a color display PDP according to claim 3 or 4, wherein a coating pitch in a direction orthogonal to a linear direction of the linear concave portion of the dispenser is adjusted to the detected interval.

Images