JP3676351B2 - Phosphor layer forming apparatus and method for forming phosphor layer of plasma display panel - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an apparatus and a method for forming a phosphor layer between ribs of a substrate that is used in a plasma display panel (PDP) manufacturing process and has a plurality of ribs (partitions) on the surface.
[0002]
[Prior art]
A PDP is a display panel having a structure in which a pair of substrates (usually glass plates) facing each other with a discharge space interposed therebetween is 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 to enable color display. A color display PDP has phosphor layers of three colors of R (red), G (green), and B (blue).
[0003]
Conventionally, each of the phosphor layers of R, G, and B has a method in which a phosphor paste mainly composed of powdered phosphor particles is sequentially applied on a substrate by a screen printing method for each color, and is fired after drying. (See, for example, JP-A-5-299019).
[0004]
[Problems to be solved by the invention]
However, as the screen size of the PDP increases, positional displacement between the rib arrangement pattern and the mask pattern occurs due to factors such as expansion / contraction / positioning errors of the screen mask, and the phosphor paste is accurately applied between the ribs. It has become difficult.
[0005]
The present invention has been made in consideration of such circumstances, and provides an apparatus and method for forming a phosphor layer uniformly and accurately between ribs of a substrate for constituting a large PDP.
[0006]
[Means for Solving the Problems]
The present invention relates to an apparatus for forming a phosphor layer by filling a phosphor paste in grooves formed between ribs for partitioning discharge spaces on a substrate in a plasma display panel manufacturing process. A placement table; a dispenser having at least one nozzle that discharges a phosphor paste having a predetermined viscosity; a transport unit that relatively moves the nozzle and the placement table; a nozzle that controls the transport unit and the dispenser; The present invention provides a phosphor layer forming apparatus comprising a control unit that moves a nozzle along a groove while discharging a phosphor paste so as to draw a thread between the grooves.
[0007]
The present invention also provides a method of forming a phosphor layer by supplying a phosphor paste from a nozzle to a groove between adjacent ribs of a plurality of ribs provided in parallel on a substrate, the nozzle and the groove The present invention provides a method for forming a phosphor layer, wherein the nozzle is moved along a groove while discharging the phosphor paste so as to draw a thread between the grooves, and the groove is filled with the phosphor paste.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
The plasma display panel (PDP) according to the present invention is such that a discharge is locally generated between two opposing substrates to excite and emit a phosphor layer partitioned on the substrate. This is composed of a pair of substrate assemblies 50 and 50a as shown in FIG. 1 (for one pixel), for example.
[0009]
In the substrate assembly 50a, a pair of sustain electrodes X and Y for generating surface discharge along the substrate surface are arranged on the inner surface of the front glass substrate 11 for each line. The sustain electrodes X and Y are each composed of a wide straight strip-like transparent electrode 41 made of an ITO thin film and a narrow straight strip-like bus electrode 42 made of a metal thin film.
[0010]
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 are translucent.
[0011]
Next, in the substrate assembly 50, the address electrodes A are arranged on the inner surface of the glass substrate 21 on the back side so as to be orthogonal to the sustain electrodes X and Y. Between each address electrode A, one linear rib, that is, rib r is provided.
[0012]
In the substrate assembly (hereinafter referred to as the substrate) 50, the discharge space 30 is partitioned by the ribs r in the line direction for each subpixel (unit light emitting region) EU, and the gap size of the discharge space 30 is defined.
[0013]
A phosphor layer 28 of three colors R, G, and B for color display is provided so as to cover the rear side wall surface including the upper portion of the address electrode A and the side surface of the rib r.
[0014]
The rib r is made of low-melting glass and is opaque to ultraviolet rays. As a method for forming the rib r, a step of providing an etching mask by photolithography on a solid film-like low-melting glass layer and patterning by sandblasting is used. In this step, the arrangement of the plurality of ribs r to be formed is determined by the pattern of the etching mask, and is parallel to each other as shown in FIG. 8 or meandering as shown in FIG. Alternatively, as shown in FIG. 18, a plurality of ribs r in which the central portion is straight and both end portions are bent in opposite directions, one end of adjacent ribs open to each other and the other end closes to each other, and the central portion is Those arranged so as to be parallel to each other are formed.
[0015]
The sustain electrode pair 12 corresponds to one line of the matrix display, and one address electrode A corresponds to one column. Three columns correspond to one pixel (pixel) EG. That is, one pixel EG includes three subpixels EU of R, G, and B arranged in the line direction.
[0016]
By the opposing discharge between the address electrode A and the sustain electrode Y, the wall charge accumulation state in the dielectric layer 17 is controlled. When a sustain pulse is alternately applied to the sustain electrodes X and Y, a surface discharge (main discharge) is generated in the subpixel EU in which a predetermined amount of wall charges exist.
[0017]
The phosphor layer 28 is excited locally by ultraviolet rays generated by surface discharge and emits visible light of a predetermined color. Of this visible light, the light transmitted through the glass substrate 11 becomes 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 in the column direction across all the lines. The light emission colors of the subpixels EU in each column are the same.
[0018]
In manufacturing such a PDP, the phosphor layer is formed by a phosphor layer forming apparatus after providing the address electrodes A and the ribs r on the substrate as shown in FIG.
In the phosphor layer forming apparatus according to the present invention, the mounting table on which the substrate is mounted is not particularly limited as long as the substrate is fixed so as to be detachable almost horizontally.
[0019]
The paste-like phosphor (phosphor paste) for forming the phosphor layer is, for example, a mixture of 10 to 50 wt% of each color phosphor material, 5 wt% of ethyl cellulose and 45 to 85 wt% of BCA.
[0020]
In addition, as a fluorescent substance for red, for example, (Y, Gd) BO _Three : Eu is used, and as a green fluorescent material, for example, Zn ₂ SiO _Four : Mn or BaAl ₁₂ O ₁₉ : Mn is used as the fluorescent material for blue, for example, 3 (Ba, Mg) O.8Al ₂ O _Three Eu can be used.
[0021]
In the nozzle of the dispenser that discharges 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 is not inserted between the ribs. Therefore, the outer diameter of the tip may be larger than the rib interval. For example, when the gap between the ribs is 170 μm, the nozzle preferably has an inner diameter of about 100 μm and an outer diameter of about 300 μm. Further, as the nozzle, a multi-nozzle in which a plurality (for example, 5 to 30) of nozzles are arranged at a predetermined coating pitch in a direction orthogonal to the rib may be used. In this case, it is efficient because a plurality of grooves are applied simultaneously.
[0022]
The fluorescent substance supply unit or dispenser for supplying the paste-like phosphor to the groove includes a nozzle, a container (syringe) containing the paste-like phosphor connected to the rear end of the nozzle, and pressure applied to the phosphor in the container. In addition, the pressure generator can be configured to be extruded to the nozzle. For this, for example, a commercially available dispenser system (system C type, manufactured by Musashi Engineering Co., Ltd.) can be used.
[0023]
In the transport unit of the present invention, the nozzle and the mounting table are relatively moved so 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 3-axis robot or a 3-axis manipulator can be used.
[0024]
In addition, although a motor, an air cylinder, a hydraulic cylinder, etc. can be used for the drive source which drives each axis | shaft, it is preferable to use a stepping motor or a servomotor with an encoder from the point of the ease of control or an accuracy.
[0025]
Further, the control unit that controls the movement operation of the transport unit and the nozzle discharge operation can be configured by a microcomputer including a CPU, a ROM, a RAM, and an I / O port and a driver circuit that drives a drive source of the nozzle transport unit.
For example, a keyboard, a tablet, or a mouse can be used as the input unit for setting the control conditions of the control unit.
[0026]
In such a phosphor layer forming apparatus, a substrate on which a plurality of ribs are formed in parallel at a predetermined pitch is placed on a mounting table, and the phosphor is moved from the tip of the nozzle while moving the tip of the nozzle relative to the substrate. The phosphor layer is applied to the grooves between the ribs by discharging.
Here, when applying phosphors of different emission colors to two grooves adjacent to each other, if the phosphor is applied to the adjacent groove immediately after applying the phosphor to one groove, the two phosphors come into contact with each other. Therefore, after the phosphor of the first color is applied to the predetermined first groove and the phosphor is dried, the second color is applied to the adjacent second groove. It is preferable to apply this phosphor.
[0027]
Various conditions regarding rib position and dimensions, for example, rib shape (straight or meandering), rib length, rib height, rib array pitch, number of rib arrays, and coating start and end points on the substrate The position (coordinates) of the nozzle, various conditions related to the nozzle, for example, the moving speed of the nozzle, the distance between the nozzle tip and the substrate (or the top of the rib), the discharge amount of the phosphor per time, etc. are input as required Is set in advance. Accordingly, the control unit can move the nozzle relative to the substrate in accordance with the set rib position and dimension.
[0028]
It is preferable that the phosphor layer forming apparatus further includes an optical sensor for detecting a positioning mark provided on the surface of the substrate because the position and position of the nozzle relative to the positions of the substrate and the ribs can be more easily confirmed. In this case, for example, a CCD camera can be used as the optical sensor.
[0029]
In the case of using an optical sensor, a positioning mark is previously provided on the substrate surface corresponding to the rib forming position. It is preferable from the viewpoint of efficiency and accuracy that this step is performed simultaneously with the rib forming step.
[0030]
That is, when the rib is formed by the printing method, the positioning mark is also simultaneously formed by the printing method. When the rib is formed by the sand blasting method, the positioning mark is also simultaneously performed by the sand blasting method.
[0031]
The control unit detects the positioning mark formed in this way with an optical sensor in advance, reads the coordinates, and moves the nozzle by determining the position and pitch of each rib based on the positioning mark in the coating process. Or a preset rib position can be corrected.
[0032]
The positioning mark may be provided corresponding to each rib, or may be provided for each predetermined number of ribs. Further, if the positioning marks are provided corresponding to the application start position and the end position, the movement control of the nozzle is performed with high accuracy. The optical sensor may detect the tip of the rib instead of the positioning mark. When detecting the tip of the rib, it is desirable to add a coloring material such as a black pigment to the rib material to form a dark-colored rib to increase the difference in brightness from the groove.
[0033]
As shown in FIG. 12, the discharge amount Q of the nozzle has a characteristic that it increases as the distance C (hereinafter referred to as clearance) C between the nozzle tip and the substrate (or the top of the rib) increases. It is preferable to keep it constant.
[0034]
The clearance C is determined to be an optimum value determined by the viscosity of the pasty phosphor and the content of the fluorescent substance, but is usually 100 to 200 μm. Conversely, the nozzle discharge amount Q may be controlled by the clearance C using this characteristic.
[0035]
Furthermore, when applying the paste-like phosphor by discharging between the ribs from the tip of the nozzle, once the application is started, the surface of the paste-like phosphor will not change even if the tip of the nozzle is slightly deviated from the normal application position. It has been confirmed that the tension is pulled back to the normal position.
[0036]
Using this characteristic, the application is started by reducing the clearance only at the start of application, that is, reducing the discharge amount, starting application, returning the clearance to the set value after a certain period of time, and returning the discharge amount to the set value. Can be started smoothly.
[0037]
Therefore, in the coating process, the distance between the nozzle tip and the substrate is kept at the first distance and the phosphor is applied, and subsequently, the distance between the nozzle tip and the substrate is larger than the first distance. It is preferable to comprise a steady coating process in which the phosphor is coated while being held at two distances.
[0038]
In addition, an effective display area is set on a part (center part) of the substrate surface, and an ineffective display area is set on a part (peripheral part) of the substrate surface adjacent to the effective display area. You may make it perform a starting application | coating process and perform a regular application | coating process in an effective display area | region.
[0039]
Further, since the clearance C changes depending on the warpage of the substrate and the variation in the height of the ribs, it is necessary to correct for each substrate. In order to correct the clearance C, a substrate (or rib height) at an arbitrary point (three or more points) in the substrate is measured, a virtual curved surface (spline curved surface) connecting these is calculated, and a predetermined value above this is calculated. The tip of the nozzle may be moved with the clearance C.
[0040]
Therefore, when the coating apparatus further includes a height sensor that detects the height from the mounting table at any point on the substrate surface, the phosphor layer forming method uses the height of any three points on the substrate surface. Preferably, the method further includes a step of detecting and a step of setting a virtual curved surface that passes through each detected point, and the tip of the nozzle is moved in parallel to the virtual curved surface in the coating step.
[0041]
The height sensor may be, for example, a known optical device that modulates the laser diode light at a high frequency and emits the light toward the object, and compares the phase of the reflected modulated wave with the reference wave to measure the distance to the object. A sensor can be used.
[0042]
【Example】
2, 3 and 4 are a perspective view, a plan view and a front view, respectively, showing a 42-inch color PDP phosphor layer forming apparatus, and FIG. 5 is a block diagram of its control circuit.
In these drawings, a mounting table 51 for mounting the substrate 50 is provided with substrate positioning pins 91 to 93 and an adsorption device (not shown) for adsorbing and fixing the substrate. It has been.
[0043]
A pair of Y-axis transfer devices (hereinafter referred to as Y-axis robots) 52 and 53 are provided on both sides of the mounting table 51, and an X-axis transfer device (hereinafter referred to as X-axis robot) 54 is provided on the Y-axis robots 52 and 53. A Z-axis direction transfer device (hereinafter referred to as Z-axis robot) 55 is mounted on the arrow X-axis robot S4 so as to be movable in the direction of arrow XX '. The Z-axis robot 55 is equipped with a syringe mounting portion 58 for detachably mounting a dispenser composed of a nozzle 56 for discharging a paste-like phosphor and a syringe 57 so as to be movable in the direction of the arrow ZZ ′. .
[0044]
Position sensors 59 and 60 for detecting positioning marks provided on the surface of the substrate 50 are installed in the X-axis robot 54 so as to be independently movable in the directions of arrows XX ′. Height sensors 61 and 62 that measure the distance (clearance) C from the tip to the top of the rib and the distance from the tip of the nozzle 56 to the surface of the phosphor paste after application have the nozzle 56 sandwiched below the syringe mounting portion 58. Fixed back and forth.
[0045]
The Y-axis robots 52 and 53 transport the X-axis robot 54 by Y-axis motors 52a and 53a. In the X-axis robot 54, the Z-axis robot 55 is transported by the X-axis motor 54a, and the position sensors 59 and 60 are transported by the sensor motors 54b and 54c, respectively. In the Z-axis robot 55, the syringe mounting part 58 is transported by the Z-axis motor 62.
[0046]
In FIG. 5, the control unit 80 incorporates a microcomputer comprising a CPU, a ROM and a RAM, receives outputs from a keyboard 81, position sensors 59, 60 and height sensors 61, 62, and receives an X-axis motor 54a, The Y-axis motors 52 and 53, the Z-axis motor 55a, the sensor motors 54b and 54c, and the air control unit 72 are driven and controlled, and various conditions input from the keyboard 81 and the progress of the coating operation are displayed in characters and images. It is displayed on the CRT 82.
[0047]
Air pressure from an air source (for example, an air cylinder) 70 is applied to the air control unit 72 via an air tube 71. The air control unit 72 receives the output from the control unit 80, applies air pressure to the syringe 57 via the air tube 73, and controls the discharge amount of the nozzle 56 to be constant.
[0048]
A procedure for forming a fluorescent layer on a 42-inch PDP substrate using this apparatus will be described with reference to the flowchart of FIG.
First, the syringe 57 containing the paste phosphor 20cc for forming the red (R) phosphor layer is mounted on the syringe mounting portion 58 together with the nozzle 56.
[0049]
As shown in FIG. 7, the substrate 50 having the non-effective display (dummy) region 50b around the effective display region 50a is mounted and fixed at a predetermined position of the mounting table 51 (step S1).
[0050]
The substrate 50 is made of a glass plate having a thickness of 3.0 mm, and the effective display area 50a of the substrate 50 is previously provided with a length L = 560 mm and a height parallel to the arrow XX ′ direction as shown in FIG. 1921 ribs r with H = 100 μm and width W = 50 μm are formed with a pitch P, and in the dummy area 50b, a positioning mark M1 indicating a coating start position, a positioning mark M2 indicating the center of the substrate, and a coating end position are indicated. A positioning mark M3 is provided in advance (FIG. 7). Since 1920 grooves are formed in the substrate 50 by 1921 ribs r, the R, G, and B phosphors are respectively applied to 640 (1920/3) grooves.
[0051]
Therefore, when the substrate is fixed, the rib height H, rib width W, number of ribs N, clearance C, nozzle discharge amount Q, phosphor paste coating thickness, nozzle moving speed V, and coordinates of height detection regions R1 to R9 (see FIG. 7) is input from the keyboard 81.
[0052]
Next, when the keyboard 81 is operated, the control unit 80 performs substrate condition detection and calculation operations (step S2). That is, the X-axis robot 54 and the Y-axis robots 52 and 53 are driven, the position of the positioning mark M2 is read via the position sensor 59, and the positions of the positioning marks M1 and M3 are read via the position sensor 60.
[0053]
Then, the points P1 to P9 at which the substrate height (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 coordinates and the coating are applied. The pitch P and the spline curved surface passing through the points P1 to P9 are calculated and set (stored) in the RAM. In this case, the pitch P is calculated from the distance between the marks M1 and M2 and the number N of ribs.
[0054]
Next, an operator attaches a syringe (with a nozzle) containing a red phosphor paste (hereinafter referred to as an R phosphor) to the syringe attachment portion 58 as a syringe 57 and a nozzle 56 (step S4), and performs an activation operation on the keyboard 81. When this is done (step S5), the tip of the nozzle 56 moves to the R phosphor application start position based on the positioning mark M1, and is held at a predetermined height (clearance) (step S6).
[0055]
Next, the nozzle 56 starts to discharge the R phosphor and simultaneously moves in the arrow X direction to start the phosphor paste application operation (step S7). When moved by the length L of one rib, the discharging and moving operation (coating operation) is stopped (steps S8 and S9).
[0056]
Next, the nozzle 56 moves in the arrow Y direction by a pitch 3P, and starts the discharge operation and the movement operation in the arrow X ′ direction (steps S10 to S12). When the nozzle 56 moves by the length L, the ejection and movement operation is stopped, and the nozzle 56 moves in the Y direction by the pitch 3P (steps S13 to S16). And the operation | movement by R fluorescent substance is complete | finished when the operation | movement of step S7-S16 is repeated and the number of application | coating reaches 640 in step S10 or S15.
[0057]
Next, the operator replaces the syringe 57 and the nozzle 56 with those for green phosphor paste (hereinafter referred to as G phosphor) and repeats the operations of steps S5 to S16 (steps S17 and S18). When 640 coating with the G phosphor is completed, the syringe 57 and the nozzle 56 are replaced with those for blue phosphor paste (hereinafter referred to as B phosphor), and 640 coating with the G phosphor is performed in the same manner as described above. Performed (steps S19 and S20).
[0058]
The application operation is stopped in each groove so that the end of application of the phosphor paste 28 is a predetermined distance d from the end of the rib r as shown in FIG. This is to prevent the applied phosphor paste from going over the end of the rib r and into the adjacent groove. In this case, it has been experimentally confirmed that d is effective if it is 0.5 mm or more.
[0059]
Further, in the application work of the above embodiment, when the application work for one groove is completed, the nozzle 56 moves in the arrow Y direction by a preset pitch 3p so as to perform the application work for the next groove. However, every time the application of one groove is completed, the start and end of the ribs that form the groove to be applied next are detected by the position sensors 59 and 60, respectively, and the detected start and end positions are detected. Based on this, the groove 56 may be applied while moving the nozzle 56. 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 due to some cause (for example, partial breakage of the rib end), the application process is set in advance without being interrupted. The next groove coating operation is performed based on the determined pitch.
[0060]
In this way, when all the operations for forming the phosphor layers of R, G, and B 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 (in FIG. It returns to the upper side of the mounting table 51 (position closest to the Y ′ direction). Therefore, the worker carries out the substrate 50 (step S21). With respect to the unloaded substrate 50, the phosphor is dried in the next step.
[0061]
During the above coating operation, the height of the tip of the nozzle 56 is controlled by the Z-axis robot 55 so as to always have a clearance C = 100 μm from the calculated spline curved surface.
[0062]
Note that the controller 80 monitors the surface height (thickness) of the phosphor paste immediately after application by the height sensor 62 and the height sensor 61 during the application work in the directions of the arrows X and X ′. When the measured thickness deviates from the preset coating thickness beyond the allowable range, the application operation (discharge and movement) of the nozzle 56 is immediately stopped, and a “coating failure” warning (alarm) and the coordinates of the nozzle stop position are stopped. Is displayed on the CRT 82. Further, the control unit 80 stores the coordinates in a built-in RAM.
[0063]
The operator removes the cause of the coating failure (for example, nozzle rounding), then replaces the substrate 50 on the mounting table 51 with a new one, and performs the coating operation again from the beginning (steps S1 to S21).
[0064]
As a result, it is possible to find the “coating failure” of the phosphor paste much earlier than in the conventional case of inspecting after completing the R, G, B three-color coating and drying processes. Therefore, the efficiency and yield of the phosphor coating operation are improved. In addition, since the occurrence location (coordinates) of the substrate in which “coating failure” has occurred is stored, repair and recoating operations are facilitated.
[0065]
Further, in this embodiment, the substrate 50 having a plurality of ribs r formed independently on the surface as shown in FIG. 8 is used. However, as shown in FIG. 9, the ends of the adjacent ribs are alternately connected. You may use what was done. According to this rib shape, the connecting portion of the end portion becomes the application end point position of each phosphor, and the string of the phosphor paste can be cut at this portion.
[0066]
Further, as shown in FIG. 18, the ribs r are formed on the substrate so that each pair of adjacent ribs r is separated from each other at one end and adjacent to each other at the other end. It is preferable to start with a wide end and end with a narrow end. This is because the phosphor paste 28 easily enters the groove at the start of application and does not protrude excessively at the end of application.
[0067]
In this embodiment, the positioning marks M1 and M3 are detected and the pitch P of the ribs r is calculated. However, as shown in FIG. 10, an auxiliary positioning mark m is provided for each predetermined number of ribs, and before the coating operation. The pitch P of the rib may be set and the mark P may be detected by the position sensor 59 or 60 during the coating operation to correct the pitch P.
The positioning marks M1, M2, M3, and m are formed at the same time when the rib r is formed on the substrate 50.
[0068]
Further, before the coating operation, the pitch P is set, the position of the rib to be finally applied is calculated from the pitch P, and the nozzle 56 is moved to the coordinates corresponding to the rib as shown in FIG. The point T may be drawn with a body, the coordinates of the point T and the coordinates of the positioning mark M3 may be detected by the position sensor 60, and the set pitch P may be corrected from the difference ΔL between the distances.
[0069]
FIG. 13 is an explanatory diagram showing a system using the apparatus shown in FIG. 2, in which an R phosphor layer forming apparatus 100R, a drying furnace 200a, a G phosphor layer forming apparatus 100G, a drying furnace 200b, and a B phosphor layer are formed. The apparatus 100B and the drying furnace 200C are connected in series via the conveyors 300a to 300e. The R phosphor layer forming apparatus 100R, the G phosphor layer forming apparatus 100G, and the B phosphor layer forming apparatus 100B are all equivalent to the phosphor layer forming apparatus shown in FIG. Each accommodates an R phosphor, a G phosphor and a B phosphor.
[0070]
In such a configuration, when 640 R phosphor layers are formed on the surface of the substrate 50 (FIG. 7) by the R phosphor layer forming apparatus 100R, the substrate 50 is transported to the drying furnace 200a by the conveyor 300a and dried. The The dried substrate 50 is conveyed to the G phosphor layer forming apparatus 100G by the conveyor 300b, and 640 G phosphor layers are formed on the surface thereof.
[0071]
Further, the substrate 50 is conveyed to the drying furnace 200b by the conveyor 300C and dried. The dried substrate 50 is conveyed to the B phosphor layer forming apparatus 100B by the conveyor 300d, and 640 B phosphor layers are formed on the surface thereof. It is formed.
[0072]
Next, the substrate 50 is transported to the drying furnace 200C by the conveyor 300e and dried. Thereafter, the substrate 50 is baked by a baking apparatus (not shown), and the R, G, B phosphor layer 28 is completed in the groove between the ribs 29 along the inner surface shape of the groove between the ribs as shown in FIG. .
[0073]
In the drying furnaces 200a to 200c, the paste-like phosphor filled in the grooves of the substrate 50 is dried at a temperature of 100 to 200 ° C. for 10 to 30 minutes to form the phosphor layer as described above. Immediately after the application of the phosphor layers of each color, the drying process is performed when the adjacent phosphors previously applied (filled) are in liquid form, and when the next phosphor to be applied (filled) comes into contact with each other, This is to prevent the surface tension from mixing over the ribs, that is, color mixing. That is, by passing through the drying process, the filled paste-like phosphor is formed along the inner surface shape of the groove between the ribs and loses the surface tension. The drying furnaces 200a to 200c employ at least one of a hot plate method, a hot air circulation method, and a far infrared ray method.
[0074]
FIG. 14 is a configuration explanatory view showing another system using the apparatus shown in FIG. 2. In this embodiment, one drying furnace is used instead of the three drying furnaces 200a to 200c of the system shown in FIG. 200 is provided, and a transfer robot 300 that transfers the substrate 50 in the directions of arrows AA ′ and BB ′ is provided instead of the conveyors 300a to 300e.
[0075]
In such a configuration, the substrate 50 is transported to the drying furnace 200 by the transport robot 300 and dried each time the phosphors of the respective colors are applied (filled) as in the system shown in FIG.
[0076]
15 and 16 are a perspective view and a cross-sectional view showing a multi-nozzle as a modified example of the syringe 57 and the nozzle 56 used in each of the above-described embodiments. In this multi-nozzle, six nozzles 56a are arranged in a line at a pitch 6 times the rib pitch P for one syringe 57a.
[0077]
And at the time of fluorescent substance application | coating, the paste-form fluorescent substance accommodated in the syringe 57a is simultaneously discharged from the six nozzles 56a. Accordingly, six phosphor layers having the same emission color are formed at a time, and the coating operation time is shortened to 1/6 as compared with the above-described embodiments.
Here, n nozzles are set to a pitch P for one syringe. _N In the case of using multi-nozzles arranged in a row, the rib pitch P and the nozzle pitch P _N The relationship between the amount of movement of the nozzle in the Y direction will be described (however, the phosphor paste has three types of R, G, and B).
[0078]
[A] When applying the phosphor paste when the nozzle moves in the reciprocating direction
The substrate shown in FIGS. 8, 9 and 18 (particularly, the substrate having ribs in which end patterns of adjacent ribs in FIGS. 9 and 18 are alternately opened) is applicable, and the nozzle arrangement pitch P is applicable. _N Is P _N = 6P, and the coating operation is performed as follows.
(1) First, the phosphor paste is simultaneously applied to the n grooves at the application pitch 6P while moving the nozzle in the X direction from the open guide (opening portion of the first groove) of the rib end pattern.
(2) Next, the nozzle is moved by 3P in the Y direction and positioned on the open side (opening portion of the second groove) of the end pattern of the rib.
(3) Next, the phosphor paste is newly applied to the n grooves while moving in the X ′ direction (the phosphor paste is applied to the total of 2n grooves at a pitch of 3P in the steps so far. become).
(4) Next, the nozzle is moved by 3P × (2n−1) in the Y direction to be positioned at the opening of the third groove.
The above steps (1) to (4) are repeated.
[0079]
[B] When applying phosphor paste during one-way movement of nozzle
The substrate shown in FIG. 8 is applicable, and the nozzle arrangement pitch P _N Is P _N = 3P, and the coating operation is performed as follows.
(1) First, the phosphor paste is simultaneously applied to the n grooves at the application pitch 3P while moving the nozzle in the forward direction (X or X ′ direction).
(2) Next, the nozzle is moved in the reverse direction without applying the phosphor paste and returned to the application start position.
(3) Next, the nozzle is moved by 3P × n in the Y direction.
The above steps (1) to (3) are repeated.
[0080]
As described above, when the application operation is performed simultaneously with the plurality of nozzles 56a, the phosphor paste is used when the end face of the nozzle tip is perpendicular to the nozzle axis even if the nozzle pitch is made to coincide with the rib pitch with high accuracy. Because of the influence of the viscosity and surface tension, the phosphor paste is difficult to be discharged directly under the tip of the nozzle, so that it is not easy to accurately apply the phosphor paste to the corresponding groove of each nozzle.
[0081]
Therefore, when using a plurality of nozzles, as shown in FIG. 19, the nozzle is formed such that the end surface of the nozzle tip forms an acute angle θ with respect to the nozzle axis, and the nozzle axis is applied to the substrate 50 in the application direction It is preferable to hold the nozzle so as to form an acute angle α so that the opening at the tip of the nozzle faces in the direction opposite to the coating direction. In this case, θ is set to 30 ° to 60 °, and α is set to 45 ° to 70 °. Thus, the phosphor paste is reliably discharged from each nozzle in the direction opposite to the application direction, and the discharge direction is fixed, so that each nozzle can accurately apply the phosphor paste to each desired groove.
[0082]
The syringe 57a is mounted on the syringe mounting portion 58 (FIG. 4) so that the nozzles 56a are arranged orthogonally to the ribs, and a mechanism for rotating the syringe 57a in the direction indicated by the arrow W in FIG. 15 is provided. If so, the application pitch of each nozzle 56a can be adjusted by the rotation.
[0083]
Furthermore, in the present invention, the coating head of the coating device for coating the curtain-like paste called slot coater or die coater is improved to a head 63 as shown in FIG. Is also possible.
[0084]
That is, the head 63 includes a reserve tank 57b for temporarily storing a phosphor paste in the head 63 and a nozzle shown in FIG. 16, as shown in FIG. 21 in the longitudinal section and in FIG. 22 in the section AA in FIG. A plurality of gaps (channels) 56b for discharging the phosphor paste corresponding to 56a are formed, and the interdigital phosphor paste is discharged from the channel 56b. When applying the above-described three color phosphor layers, the head 63 corresponding to each color is arranged as described above to complete the entire application.
[0085]
【The invention's effect】
According to the present invention, the phosphor is discharged from the nozzle that moves on the substrate only by setting the numerical value of the substrate without using a conventional screen mask, and is applied to the groove between the ribs. In contrast, the phosphor layer can be formed with high accuracy and can easily cope with a change in specifications of the substrate.
[Brief description of the drawings]
FIG. 1 is a perspective view of an essential part of a plasma display panel according to the present invention.
FIG. 2 is a perspective view showing an apparatus according to an embodiment of the present invention.
FIG. 3 is a plan view showing an apparatus according to an embodiment of the present invention.
FIG. 4 is a front view showing an apparatus according to an embodiment of the present invention.
FIG. 5 is a block diagram illustrating a control unit according to an embodiment of the present invention.
FIG. 6 is a flowchart showing the operation of the embodiment of the present invention.
FIG. 7 is a top view showing a substrate according to an embodiment of the present invention.
8 is an enlarged view of a main part of FIG.
FIG. 9 is an enlarged view of a main part showing a modified example of a rib of a substrate applied to the present invention.
FIG. 10 is a top view showing a modified example of the substrate applied to the present invention.
11 is an enlarged view showing another method for correcting the rib pitch in the substrate shown in FIG. 7; FIG.
FIG. 12 is a graph showing the relationship between clearance and phosphor discharge amount in the present invention. .
FIG. 13 is a configuration explanatory diagram showing a system of the present invention.
FIG. 14 is a configuration explanatory view showing another system of the present invention.
FIG. 15 is a perspective view showing a modified example of the nozzle according to the embodiment of the present invention.
16 is a cross-sectional view of the nozzle shown in FIG.
FIG. 17 is a top view showing the positional relationship between the end of the rib and the application end of the phosphor paste according to the embodiment of the present invention.
FIG. 18 is a top view showing a modification of the ribs of the substrate to which the present invention is applied.
FIG. 19 is a side view showing a modification of the tip of the nozzle of the present invention.
FIG. 20 is a perspective view showing a coating head as another modified example of the nozzle of the present invention.
21 is a longitudinal sectional view of the coating head shown in FIG.
22 is a cross-sectional view taken along the line AA in FIG. 21. FIG.
[Explanation of symbols]
50 substrates
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 nozzles
57 syringe
58 Syringe mounting part
59 Position sensor
60 Position sensor
61 Height sensor
91 pins
92 pins
93 pins

Claims (16)

An apparatus for forming a phosphor layer by filling a phosphor paste in grooves formed between ribs for partitioning a discharge space on a substrate in a plasma display panel manufacturing process,
A mounting table for mounting the substrate, a dispenser having at least one nozzle that is held at a position higher than the ribs of the substrate and discharges a phosphor paste of a predetermined viscosity, and a transport unit that relatively moves the nozzle and the mounting table Then, the nozzle is moved from one end of the groove toward the other end while discharging the phosphor paste so as to pull the yarn by the surface tension of the phosphor paste between the nozzle and the groove by controlling the transport unit and the dispenser. A phosphor layer forming apparatus comprising a control unit for controlling the phosphor layer. The dispenser includes a plurality of nozzles for discharging phosphor paste of the same color , and the plurality of nozzles correspond to three types of phosphors to be applied to grooves between ribs provided on the substrate. The phosphor layer forming apparatus according to claim 1, wherein the phosphor layer forming apparatus has a configuration in which the phosphor pastes of the same color in a plurality of grooves are simultaneously applied from each nozzle arranged at intervals of an integral multiple of the grooves. Three phosphor coating devices corresponding to each color of the three types of phosphors are arranged via a substrate transporter, and the nozzles of each device have an arrangement pitch of each of three types of grooves on every two of the grooves on the substrate. The phosphor layer forming apparatus according to claim 2 , wherein the phosphor layer forming apparatus is provided at intervals of an integer multiple . An apparatus for forming a phosphor layer by filling a phosphor paste in a groove formed between ribs for partitioning a discharge space on a substrate in a plasma display panel manufacturing process, on which a substrate is placed A dispenser having at least one nozzle that discharges a phosphor paste of a predetermined viscosity, a transport unit that relatively moves the nozzle and the mounting table, and a space between the nozzle and the groove by controlling the transport unit and the dispenser A control unit that moves the nozzle along the groove while discharging the phosphor paste so as to pull the yarn, and the control unit further has a function of controlling the nozzle discharge amount by changing the distance between the nozzle tip and the substrate. A phosphor layer forming apparatus. An apparatus for forming a phosphor layer by filling a phosphor paste in a groove formed between ribs for partitioning a discharge space on a substrate in a plasma display panel manufacturing process, on which a substrate is placed A dispenser having at least one nozzle that discharges a phosphor paste of a predetermined viscosity, a transport unit that relatively moves the nozzle and the mounting table, and a space between the nozzle and the groove by controlling the transport unit and the dispenser A control unit that moves the nozzle along the groove while discharging the phosphor paste so as to pull the yarn, and the substrate to be used has a positioning mark and detects at least one of the positioning mark on the substrate and the tip of the rib The control unit further includes a position sensor, and the control unit and the transport unit are arranged on the basis of at least one of the positioning mark and the rib tip detected by the position sensor. Further fluorescent body layer forming apparatus having a function of controlling the Supensa.   6. The control unit according to claim 5, further comprising a function of presetting a coating pitch of the phosphor paste and correcting the coating pitch based on at least one of a positioning mark and a rib tip detected by the position sensor. Phosphor layer forming apparatus. An apparatus for forming a phosphor layer by filling a phosphor paste in a groove formed between ribs for partitioning a discharge space on a substrate in a plasma display panel manufacturing process, on which a substrate is placed A dispenser having at least one nozzle that discharges a phosphor paste of a predetermined viscosity, a transport unit that relatively moves the nozzle and the mounting table, and a space between the nozzle and the groove by controlling the transport unit and the dispenser in a control unit for moving the nozzle while discharging the phosphor paste to draw the thread along the groove, Bei give a height sensor for detecting the height of the table for any point on the substrate, the control unit further comprising fluorescent functions to control the transport unit and dispenser so that the distance based on the height between the nozzle tip and the substrate during the phosphor paste applied to be detected by the height sensor is adjusted Layer forming apparatus.   The control unit detects in advance the height of any three points on the surface of the substrate or rib placed by the height sensor, sets a virtual curved surface that passes through each detected point, and the nozzle tip is parallel to the virtual curved surface. The phosphor layer forming apparatus according to claim 7, further comprising a function of controlling the transport unit and the dispenser so that the phosphor paste is applied to the groove by moving to the groove. An apparatus for forming a phosphor layer by filling a phosphor paste in a groove formed between ribs for partitioning a discharge space on a substrate in a plasma display panel manufacturing process, on which a substrate is placed A dispenser having at least one nozzle that discharges a phosphor paste of a predetermined viscosity, a transport unit that relatively moves the nozzle and the mounting table, and a space between the nozzle and the groove by controlling the transport unit and the dispenser a control unit for moving the nozzle to the groove while discharging the phosphor paste to draw the yarn in, e Bei a second height sensor for detecting the coating thickness of the phosphor paste applied to the groove, the control parts when the coating thickness detected by the second height sensor deviates from the predetermined allowable range, further fluorescent body layer forming apparatus having a function of stopping the application of the phosphor paste. An apparatus for forming a phosphor layer by filling a phosphor paste in a groove formed between ribs for partitioning a discharge space on a substrate in a plasma display panel manufacturing process, on which a substrate is placed A dispenser having at least one nozzle that discharges a phosphor paste of a predetermined viscosity, a transport unit that relatively moves the nozzle and the mounting table, and a space between the nozzle and the groove by controlling the transport unit and the dispenser in example Bei a control unit for moving the nozzle to the groove while discharging the phosphor paste to draw the yarn, a position sensor for detecting a rib tip, the control unit, the rib tip is clearly detected by the position sensor In this case, based on the detected rib tip, if it cannot be clearly detected, the function of controlling the transport unit and the dispenser is further controlled based on a preset rib pitch. With a fluorescent body layer forming apparatus. An apparatus for forming a phosphor layer by filling a phosphor paste in a groove formed between ribs for partitioning a discharge space on a substrate in a plasma display panel manufacturing process, on which a substrate is placed A dispenser having at least one nozzle that discharges a phosphor paste of a predetermined viscosity, a transport unit that relatively moves the nozzle and the mounting table, and a space between the nozzle and the groove by controlling the transport unit and the dispenser The control unit moves the nozzle along the groove while discharging the phosphor paste so as to pull the yarn, and the control unit has the phosphor paste application end of each groove a short distance from the end of the rib. further fluorescent body layer forming apparatus having a function of controlling the transport unit and the dispenser so as to be positioned.   The phosphor layer forming apparatus according to claim 1, wherein the nozzle has an end face formed obliquely with respect to the axis of the nozzle.   The phosphor layer forming apparatus according to claim 12, wherein the nozzle is held so as to form an acute angle in the coating direction with respect to the substrate. A method of applying phosphor pastes of three kinds of colors to a groove formed between a plurality of ribs provided in parallel at a pitch P on a substrate using the phosphor layer forming apparatus according to claim 1. The dispenser includes n nozzles arranged at intervals of 6P. (1) The phosphor paste is simultaneously applied to the n grooves at an application pitch 6P while moving the nozzles in the forward direction. (2) The nozzle is moved in the direction orthogonal to the rib by 3P, (3) The phosphor paste is applied to the n grooves while moving the nozzle in the opposite direction, and (4) the nozzle is moved by 3P × (2n−1) to the rib. Move in the orthogonal direction,
A phosphor coating method characterized by repeating the steps (1) to (4). A method of forming a phosphor layer by supplying a phosphor paste from a nozzle to a groove between adjacent ribs of a plurality of ribs provided in parallel on a substrate, wherein a phosphor paste having a predetermined viscosity is discharged. The nozzle is moved from one end of the groove to the other end while discharging the phosphor paste so that the thread is pulled by the surface tension of the paste between the tip of the nozzle and the groove, and the phosphor paste is filled into the groove. A method for forming a phosphor layer. A method of forming a phosphor layer by supplying a phosphor paste from a nozzle to a groove between adjacent ribs of a plurality of ribs provided in parallel on a substrate, wherein a thread is drawn between the nozzle and the groove The nozzle is moved along the groove while discharging the phosphor paste, and the groove is filled with the phosphor paste, and the filling operation of the phosphor paste is terminated by a predetermined distance from the end of the rib. Forming a phosphor layer.

Images