JPH117890A - Phosphor layer forming method and device of plasma display panel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form a uniform phosphor layer by moving a nozzle to continuously deliver phosphor paste from one end of a groove formed between plural ribs arranged in parallel in a first area of a base board surface, moving it up to one end of the next groove by pssing through a second area to surround the first area after reaching the other end, and repeating to move the next groove in the inverse direction. SOLUTION: An X axis robot 54 movable in its Y-Y' direction is mounted on Y axis robots 52 and 53 of a pair of Y axis directional carrying devices on a mounting stand 51, and a Z axis robot 55 is mounted on its X axis robot 54. A nozzle is installed in a syringe installing part 58 of a Z axis robot 55. A protective cover is added to a peripheral dummy area of an effective area of a base board 50. The nozzle delivers phosphor paste by starting operation, and starts applying work to a groove by moving in the X direction. It moves in the Y direction on the protective cover without stopping delivery when it moves by a length of a single rib, and starts to move in the X' direction. This operation is repeated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for forming a phosphor layer between ribs of a substrate having a plurality of ribs (partitions) on a surface, which is used in a manufacturing process of a plasma display panel (PDP). .

[0002]

2. Description of the Related Art A PDP is a display panel having a structure in which a pair of substrates (usually, glass plates) opposed to each other with a discharge space interposed therebetween is used as a base. In the PDP, by providing an ultraviolet excitation type phosphor layer in the discharge space, the phosphor layer is excited by the discharge, and a color can be displayed. PDP for color display
Has phosphor layers of three colors of R (red), G (green), and B (blue).

Conventionally, each of the phosphor layers of R, G, and B is formed by applying a phosphor paste containing powdered phosphor particles as a main component on a substrate in order for each color by a screen printing method, and drying and firing. (See, for example, Japanese Patent Application Laid-Open No. H5-299019).

[0004]

SUMMARY OF THE INVENTION However, PDP
As the screen size of the screen increases, misalignment between the rib arrangement pattern and the mask pattern occurs due to factors such as expansion and contraction and positioning errors of the screen mask, making it difficult to accurately apply the phosphor paste between the ribs. It has become

Therefore, the inventors of the present invention have proposed a large PD
As an apparatus for uniformly and accurately forming a phosphor layer between each rib of a substrate for forming P, a nozzle for discharging the phosphor paste is applied to predetermined grooves between the ribs sequentially with the phosphor paste. (Japanese Patent Application No. 8-337189) has been proposed.

When the proposed phosphor layer forming apparatus is used, usually, the nozzle is moved along the groove while discharging the phosphor paste, and when the nozzle reaches the vicinity of the end of the groove, the phosphor of the nozzle is usually moved. After the discharge of the paste is stopped, the nozzle is moved to the beginning of the next groove, and the discharge of the phosphor paste is started again. This results in intermittent discharge of the phosphor paste from the nozzles, and the intermittent discharge of the nozzles causes clogging of the nozzles and changes in the discharge amount. The phenomenon that uniformity was impaired was observed.

The present invention has been made in consideration of such circumstances, and a phosphor paste is applied continuously without interrupting the discharge of a nozzle, thereby forming a uniform phosphor layer. The present invention provides a method and apparatus for performing the above.

[0008]

According to the present invention, a first region and a second region surrounding the first region are set on a substrate surface, and the first region is formed.
A plurality of ribs are provided in parallel in the region, and a nozzle that discharges the phosphor paste is moved in a forward direction along the groove from one end to the other end of the groove formed between the ribs, and the nozzle that reaches the other end is The process of moving to the one end of the next groove through the second region and moving in the opposite direction along the groove from one end of the next groove to the other end is repeated, and the nozzle is moved to any one of the first and second regions. It is an object of the present invention to provide a method for forming a phosphor layer of a plasma display panel, characterized in that a phosphor paste is continuously discharged to a nozzle without interruption even when the phosphor paste is present in a region.

The present invention further provides a phosphor layer forming apparatus for applying a phosphor paste to a groove formed between a plurality of ribs provided in parallel on a substrate surface in a process of manufacturing a plasma display panel. A transport unit that moves the nozzle that discharges the paste with respect to the substrate, an elevating unit that moves the nozzle up and down with respect to the substrate, and a tray between the nozzle and the substrate for receiving the phosphor paste that the nozzle discharges when the nozzle is raised An object of the present invention is to provide an apparatus for forming a phosphor layer of a plasma display panel, which is provided with a tray insertion portion for insertion.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION A plasma display panel (PDP) according to the present invention generates a discharge locally between two opposing substrates to excite and emit light from a phosphor layer partitioned on the substrates. It was made. this is,
For example, a pair of substrate assemblies 5 as shown in FIG.
0, 50a.

In the substrate assembly 50a, a pair of sustain electrodes X and Y for generating a surface discharge along the substrate surface are arranged on the inner surface of the glass substrate 11 on the front side. Each of the sustain electrodes X and Y is a wide linear band-shaped transparent electrode 4 made of an ITO thin film.
1 and a narrow strip-shaped bus electrode 42 made of a metal thin film
It is composed of

The bus electrode 42 is an auxiliary electrode for ensuring proper conductivity. A dielectric layer 17 is provided so as to cover the sustain electrodes X and Y, and a protective film 18 is deposited on the surface of the dielectric layer 17. Both the dielectric layer 17 and the protective film 18 have translucency.

Next, in the substrate assembly 50,
On the inner surface of the glass substrate 21 on the back side, the sustain electrodes X,
The address electrodes A are arranged to be orthogonal to Y. One linear rib r is provided between each address electrode A. In the substrate assembly (hereinafter, referred to as a substrate) 50, the discharge space 30 is divided in the line direction for each subpixel (unit light emitting region) by the ribs r, and the gap size of the discharge space 30 is defined.

The upper portion of the address electrode A and the rib r
R, G, and B phosphor layers 28R, 28 for color display so as to cover the rear wall surface including the side surfaces of
G and 28B are provided.

The ribs r are made of low melting point glass and are opaque to ultraviolet rays. As a method for forming the ribs r, a step of providing an etching mask by photolithography on a solid film-like low melting point glass layer and patterning by sandblasting is used.

A pair of sustain electrodes X and Y correspond to a line L in a matrix display, and one address electrode A corresponds to one column. Then, three columns correspond to one pixel (pixel). That is, one pixel is arranged in the line L direction 3
It consists of three sub-pixels R, G, B.

The state of accumulation of wall charges in the dielectric layer 17 is controlled by the opposite discharge between the address electrode A and the sustain electrode Y. When a sustain pulse is alternately applied to the sustain electrodes X and Y, a surface discharge (main discharge) occurs in a sub-pixel in which a predetermined amount of wall charge exists.

The phosphor layers 28R, 28G and 28B are locally excited by ultraviolet rays generated by surface discharge and emit visible light of a predetermined color. Of this visible light, the light that passes through the glass substrate 11 is the display light. Since the arrangement pattern of the ribs r is a so-called stripe pattern, the portion corresponding to each column in the discharge space 30 is continuous across all the lines L in the column direction (the arrangement direction of the ribs r). I have. The emission colors of the sub-pixels in each column are the same.

In manufacturing such a PDP, a phosphor layer is formed by a phosphor layer forming apparatus after providing an address electrode A and a rib r on a substrate as shown in FIG. The paste-like phosphor (phosphor paste) for forming the phosphor layer is, for example, a phosphor 1 for each color.
0-50 wt%, ethyl cellulose 5 wt% and BC
A is a mixture of 45 to 85 wt%.

The fluorescent substance for red includes, for example,
(Y, Gd) BO ₃ : Eu is used, and as a green fluorescent substance, for example, Zn ₂ SiO ₄ : Mn or BaAl ₁₂ O ₁₉ :
M, and as the blue fluorescent substance, for example, 3 (B
a, it is possible to use _{Mg) O · 8Al 2 O 3} Eu.

In the nozzle for discharging the paste-like phosphor, the inner diameter of the nozzle is set to be smaller than that corresponding to the rib interval, but the tip of the nozzle may be inserted between the ribs. Therefore, the outer diameter of the tip may be larger than the rib interval.

For example, when the rib interval is 170 μm, the nozzle preferably has an inner diameter of about 100 μm and an outer diameter of about 300 μm. In addition, a plurality of nozzles (for example, 5
A multi-nozzle in which (about 30) nozzles are arranged at a predetermined application pitch in a direction orthogonal to the ribs may be used. In this case, since a plurality of grooves are applied simultaneously, efficiency is improved.

The first region in the substrate of the present invention is a region occupying 90% or more of the substrate area at the center of the substrate.
The second area is a dummy (margin) area set on the periphery of the first area. The second area is used as a support part when assembling the PDP and as a part for installing wiring components.

The nozzle for supplying the paste-like phosphor to the groove includes a container (syringe) containing the paste-like phosphor connected to the rear end of the nozzle and applying pressure to the phosphor in the container to push the phosphor into the nozzle. For example, a commercially available dispenser system (System C, manufactured by Musashi Engineering Co., Ltd.) can be used.

In the transfer unit and the elevating unit of the present invention, the nozzle substrate is moved relative to the nozzle substrate such that the nozzle tip moves in three directions: a direction parallel to the rib of the substrate, a direction perpendicular to the rib, and a direction perpendicular to the substrate. For example, a three-axis robot or a three-axis manipulator can be used.

In the tray insertion portion of the present invention, the tray is inserted between the nozzle and the substrate when the nozzle is pulled up from the substrate by the elevating portion to a distance in which the tray can be inserted. You may make it provide in the front-end | tip of an electric arm.

By providing the tray insertion portion, the phosphor paste discharged from the nozzle is received by the tray except when the phosphor paste is applied to the grooves. Therefore, even when the nozzle constantly discharges the phosphor paste, the phosphor paste is not applied to the unnecessary area.

The phosphor paste received in the receiving tray may be returned to a supply source for supplying the phosphor paste to the nozzle, and may be reused. In addition, a motor, an air cylinder, a hydraulic cylinder, or the like can be used as a drive source for driving the transport unit, the lifting unit, and the tray insertion unit.

Embodiment 1 FIGS. 2, 3 and 4 each show a 42-inch color P
FIG. 5 is a perspective view, a plan view, and a front view showing a DP phosphor layer forming apparatus, and FIG. 5 is a block diagram of a control circuit thereof.

In these figures, a mounting table 51 for mounting a substrate 50 has positioning pins 91 to 9 for the substrate.
3, a suction device (not shown) for sucking and fixing the substrate is provided.

A pair of Y-axis direction transfer devices (hereinafter, referred to as Y-axis robots) 52, 53 are provided on both sides of the mounting table 51, and an X-axis direction transfer device (hereinafter, referred to as X-axis robot) 5 is provided.
4 is mounted on Y-axis robots 52 and 53 so as to be movable in the direction of arrow YY ′, and a Z-axis direction transfer device (hereinafter referred to as Z-axis robot) 55 is attached to arrow X-axis robot 54 by arrow XX ′.
It is mounted so that it can move in any direction.

On the Z-axis robot 55, a syringe mounting portion 58 for detachably mounting a dispenser composed of a nozzle 56 for discharging paste-like phosphor and a syringe 57 is movably mounted in the direction of the arrow ZZ '. Have been.

A rib r provided on the surface of the substrate 50
Sensors 59, 6 for detecting the start and end of the
0 is installed on the X-axis robot 54 so as to be independently movable in the direction of the arrow XX ′, and the distance (clearance) C from the tip of the nozzle 56 to the top of the rib and the nozzle 56
The height sensors 61 and 62 for measuring the distance from the tip of the substrate to the surface of the phosphor paste after application are fixed to the front and back of the syringe mounting portion 58 with the nozzle 56 interposed therebetween.

In the Y-axis robots 52 and 53, the X-axis robot 54 is transported by the Y-axis motors 52a and 53a.
In the X-axis robot 54, the Z-axis motor 54a
The axis robot 55 is conveyed, and the sensor motors 54b, 54
The position sensors 59 and 60 are respectively conveyed by c.
In the Z-axis robot 55, the syringe mounting unit 58 is transported by the Z-axis motor 55a.

In FIG. 5, the control unit 80 includes a CPU, an R
A microcomputer including an OM and a RAM is built in and receives outputs from the keyboard 81, the position sensors 59 and 60 and the height sensors 61 and 62, and receives signals from the X-axis motor 5.
4a, Y-axis motors 52, 53, Z-axis motor 55a,
In addition to controlling the driving of the sensor motors 54b and 54c and the air control unit 72, the CRT 82 displays various conditions input from the keyboard 81 and the progress of the coating operation in characters and images.
To be displayed.

An air pressure from an air source (for example, an air cylinder) 70 is applied to an air control unit 72 via an air tube 71. The air control unit 72 receives the output from the control unit 80 and changes the air pressure through the air tube 73 to the syringe 5.
7, the discharge amount of the nozzle 56 is controlled to be constant.

The procedure for forming a fluorescent layer on a substrate for a 42-inch PDP using this apparatus will be described with reference to the flowchart of FIG. First, as shown in FIG. 7, a substrate 50 having a dummy area (second area) 50b around an effective display area (first area) 50a is mounted at a predetermined position on a mounting table 51 and fixed (step S1). . In addition, as shown in FIGS. 7 to 9, the protective cover 86 is provided in the dummy area 50b.
a, 86b are detachably attached in advance. For the protective covers 86a and 86b, for example, an adhesive tape-like plastic film is used.

The substrate 50 is made of a glass plate having a thickness of 3.0 mm.
As shown in FIG. 8, the length L = 5 parallel to the direction of the arrow XX ′.
1921 ribs r having a pitch P of 60 mm, a height H = 100 μm, and a width W = 50 μm are formed. Since 1920 grooves are formed by the 1921 ribs r in the effective display area 50a, the R, G, and B phosphors are applied to 640 (1920/3) grooves, respectively. Become.

Therefore, when fixing the substrate, the rib height H, the rib width W, the number of ribs N, the clearance C, the nozzle discharge amount Q,
Set values such as the thickness of the phosphor paste application, the nozzle moving speed V, and the coordinates of the height detection areas R1 to R9 (see FIG. 7) are input from the keyboard 81.

Next, when the keyboard 81 is operated, the control unit 80 detects the board condition and performs an operation (step S).
2). That is, the X-axis robot 54, the Y-axis robot 52,
By driving the position 53, the start position and the end position of each rib r are read via the position sensor 59 and the position sensor 60.

Then, the points P1 to P9 at which the substrate height (the height from the mounting table 51) in each of the set regions R1 to R9 is maximum are detected via the height sensor 61, and the rib start is started. Coordinates, average application pitch P, and point P1
ＰP9 are calculated and set (stored) in the RAM.

Next, the operator mounts the syringe (with nozzle) containing the red phosphor paste (hereinafter referred to as R phosphor) as the syringe 57 and the nozzle 56 on the syringe mounting section 58 (step S4). When the starting operation is performed, the nozzle 56 starts discharging the R phosphor (Step S5), and the tip of the nozzle 56 moves to the R phosphor application start position. (Step S6).

Next, the nozzle 56 moves in the direction of arrow X,
The operation of applying the phosphor paste to the grooves is started (step S7). When the nozzle 56 moves by the length L of one rib (step S8), the nozzle 56 moves on the protective cover 86a or 86b by the pitch 3P in the arrow Y direction without stopping the ejection operation, and further moves in the arrow X 'direction. The movement operation is started (steps S9 to S12). When the nozzle 56 moves by the length L, the nozzle 56 moves on the protective cover 86a or 86b by the pitch 3P in the Y direction without stopping the ejection operation (Steps S13 to S16). And step S7 ~
The operation of S16 is repeated, and when the number of coatings reaches 640 in step S10 or S15, the operation using the R phosphor ends.

Next, the operator operates the syringe 57 and the nozzle 56.
Is replaced with a paste for a green phosphor paste (hereinafter, referred to as a G phosphor), and the operations in steps S5 to S16 are repeated (steps S17 and S18). 640 by G phosphor
When the book application is completed, the syringe 57 and the nozzle 56 are replaced with those for a blue phosphor paste (hereinafter, referred to as a B phosphor), and 640 applications using the G phosphor are performed as described above (step S19). , S20).

In the coating operation of the above embodiment,
When the application of one groove is completed, the nozzle 56 moves in the direction of the arrow Y by a preset pitch 3p to perform the application of the next groove. Each time is finished, the start and end of the rib forming the groove to be applied next are detected by the position sensors 59 and 60, respectively, and the nozzle 56 is moved while moving the nozzle 56 based on the detected start and end positions. The application operation may be performed. This further improves the accuracy of applying the phosphor paste to each groove.

In this case, if the position sensors 59 and 60 cannot detect the start or end of the rib for some reason (for example, partial breakage of the rib end), the coating process is not interrupted. The next groove application operation is performed based on the preset pitch. In addition, the nozzle 56
Is applied onto the protective covers 86a and 86b, so that the dummy region 50b is protected from the application of the phosphor paste.

In this manner, when all the operations of forming the R, G, and B phosphor layers along the inner surface shape of the groove between the ribs as shown in FIG. 1 are completed, the X-axis robot 54 moves to the home position (FIG. In (3), it returns to the position closest to the upper side of the mounting table 51 in the Y ′ direction). Therefore, the operator unloads the substrate 50 and removes the protective covers 86a and 86b (Step S21). The phosphor is dried on the unloaded substrate 50 in the next step.

During the above coating operation, the Z-axis robot 5 is set so that the tip of the nozzle 56 always has a clearance C = 100 μm from the calculated spline curved surface.
5, the height is controlled.

Embodiment 2 FIG. 10 is a view corresponding to FIG. 4 showing Embodiment 2 of the present invention.
FIG. 12 is a view corresponding to FIG. 5 showing a second embodiment of the present invention.
As shown in FIG. 10, a tray insertion portion 86 is provided on the back surface of the Z-axis robot 55 according to the first embodiment, and the tray insertion portion 86 is provided.
Includes a pan driving motor 83, an arm 85 provided orthogonal to the output shaft of the motor 83, and a pan 84 provided at the tip of the arm 85. Further, as shown in FIG. 12, the control unit 80a has a function of driving the tray drive motor 83, but the other configuration is the same as that of the first embodiment shown in FIG.

In this configuration, the substrate 50 is mounted on the mounting table 51 in the same manner as in the first embodiment, and R, G, and R are provided in the grooves between the plurality of ribs r provided in the effective display area 50a of the substrate 50.
The B phosphor is applied.

In the second embodiment, similarly to the first embodiment, when the discharge of the phosphor paste is started, the nozzle 56 continues without interruption until it reaches the end of the last groove. In the second embodiment, the protective covers 86a and 86b attached to the dummy area 50b in the first embodiment are not used, but the tray 84 is used instead.

That is, when the nozzle 56 reaches the dummy area 50b, the control unit 80a drives the Z-axis motor 55a to raise the nozzle 56 by the distance in which the tray 84 can be inserted as shown in FIG. The tray 83 is driven to move the tray 84 below the nozzle 56.

As a result, in the dummy area 50b, the phosphor paste discharged from the nozzle 56 is received in the tray 84. When the nozzle 56 moves by 3P in the dummy area 50b and reaches the end of the groove to be applied next, the controller 80a drives the motor 83 to return the tray 84 to the position shown in FIG. 56 is returned to a predetermined application height (clearance), and the application operation to the groove is started. All other operations are the same as in the first embodiment.

As described above, according to the second embodiment, the phosphor paste discharged from the nozzle 56 in the dummy area 50b is received in the tray, so that the
No phosphor paste is applied to 6.

[0055]

According to the present invention, the phosphor paste discharged from the nozzles is continued without interruption in any region on the substrate, so that the clogging of the nozzles and the change in the discharge amount are eliminated, and the stable coating is achieved. Work becomes possible, and a high quality plasma display panel can be obtained.

[Brief description of the drawings]

FIG. 1 is a perspective view of a main part of a plasma display panel according to the present invention.

FIG. 2 is a perspective view showing an apparatus according to Embodiment 1 of the present invention.

FIG. 3 is a plan view showing the device of Embodiment 1 of the present invention.

FIG. 4 is a front view showing the device according to the first embodiment of the present invention.

FIG. 5 is a block diagram illustrating a control unit according to the first embodiment of the present invention.

FIG. 6 is a flowchart showing the operation of the first embodiment of the present invention.

FIG. 7 is a top view showing a substrate according to the first embodiment of the present invention.

FIG. 8 is an enlarged view of a main part of FIG. 7;

FIG. 9 is a side view of the substrate according to the first embodiment of the present invention.

FIG. 10 is a diagram corresponding to FIG. 4 of a second embodiment of the present invention.

FIG. 11 is an explanatory diagram illustrating an operation of the second embodiment.

FIG. 12 is a diagram corresponding to FIG. 5 of the second embodiment.

[Explanation of symbols]

 Reference Signs List 50 board 51 mounting table 52 Y-axis robot 52a Y-axis motor 53 Y-axis robot 53a Y-axis motor 54 X-axis robot 54a X-axis motor 54b Sensor motor 54c Sensor motor 55 Z-axis robot 55a Z-axis motor 56 Nozzle 57 Syringe 58 Syringe mounting part 59 Position sensor 60 Position sensor 61 Height sensor 91 pin 92 pin 93 pin

Claims (4)

[Claims] 1. A first region and a second region surrounding the first region are set on a substrate surface, a plurality of ribs are provided in parallel in the first region, and a nozzle for discharging a phosphor paste is provided on the substrate. One end of the next groove is moved from one end of the next groove to one end of the next groove by moving the nozzle in the forward direction along the groove from one end of the groove formed therebetween to the other end through the second area. Repeating the step of moving the phosphor paste in the reverse direction along the groove, and continuously ejecting the phosphor paste to the nozzle without interruption even when the nozzle is present in any of the first and second areas. A method for forming a phosphor layer of a plasma display panel, comprising: 2. The method for forming a phosphor layer of a plasma display panel according to claim 1, wherein a protective cover is previously set in the second area so as to be detachable, and the second area is protected from adhesion of the phosphor paste. 3. The phosphor according to claim 1, wherein when the nozzle is located in the second region, a receiving tray for receiving the phosphor paste discharged from the nozzle is inserted between the nozzle and the second region. Layer forming method. 4. A phosphor layer forming apparatus for applying a phosphor paste to a groove formed between a plurality of ribs provided in parallel on a substrate surface in a process of manufacturing a plasma display panel, wherein the phosphor paste is discharged. A transport unit that moves a nozzle to be moved with respect to a substrate, an elevating unit that moves the nozzle up and down with respect to the substrate, and a tray that receives a phosphor paste discharged from the nozzle when the nozzle is raised is inserted between the nozzle and the substrate An apparatus for forming a phosphor layer of a plasma display panel comprising an insertion section.