JP3928686B2 - Phosphor layer forming apparatus for plasma display panel and method for forming the same - 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 which is used in a manufacturing process of a plasma display panel (hereinafter referred to as PDP) and has a plurality of ribs (partition walls) on the surface.
[0002]
[Prior art]
2. Description of the Related Art Conventional PDP phosphor layer forming apparatuses and methods are known in which phosphor paste is applied to grooves between ribs using a nozzle head having a plurality of nozzles (so-called multi-nozzles). However, as the size of the PDP increases, that is, the size of the substrate increases, it becomes difficult to apply the entire surface of the substrate at once, and the substrate application region is divided into a plurality of small regions corresponding to the applicable width of the nozzle head. Each of the small areas has been sequentially applied with a nozzle head.
[0003]
By the way, if the amount of the phosphor paste applied to the groove between the ribs or the concentration of the phosphor contained in the phosphor paste varies, it adversely affects the display characteristics of the PDP. In order to obtain it, it is necessary to manage the coating amount and the concentration of the fluorescent substance in the paste with high accuracy.
Therefore, it is known that the viscosity of the phosphor paste is set to be relatively low and is applied by utilizing the surface tension of the phosphor paste, or the relationship between the nozzle length and the aperture is variously controlled ( For example, refer to JP-A-11-40065 and JP-A-11-73882).
[0004]
[Problems to be solved by the invention]
However, in order to manufacture a large PDP with high display quality, it is necessary to further solve the following points.
That is, it is often seen that the phosphor paste is applied to the top of one of the ribs as well as the inner wall of the rib due to the positional deviation between the groove between the two ribs and the nozzle. However, if the ribs to be applied to the top are not specified as either one and are different for each application region of the nozzle head, uneven display of the PDP, so-called unevenness occurs at the boundary.
[0005]
The present invention has been made in consideration of such circumstances, and a phosphor layer forming apparatus capable of preventing the occurrence of display unevenness of a PDP by specifying one of the ribs to be applied up to the top, and The formation method is provided.
[0006]
[Means for Solving the Problems]
The present invention is an apparatus for forming a phosphor layer by applying a phosphor paste to a groove formed between a plurality of ribs provided in parallel on a substrate surface, and a mounting table on which a substrate is mounted; A nozzle head having a nozzle for discharging the phosphor paste, a supply unit for supplying the phosphor paste to the nozzle head, and an X direction in which the nozzle head and the mounting table are relatively moved so that the nozzle head moves in parallel with the rib A moving unit, a Y-direction moving unit that relatively moves the nozzle head and the mounting table so that the nozzle head moves perpendicular to the rib, and a control for driving and controlling the supply unit, the X-direction moving unit, and the Y-direction moving unit. And when the control unit drives the X-direction moving unit to apply the phosphor paste to the groove between the ribs, the nozzle is moved from the center of the corresponding two ribs to the direction of one rib by a predetermined distance. Be biased There is provided a phosphor layer forming apparatus of the plasma display panel, characterized in that the initial setting.
[0007]
From another point of view, the present invention provides a phosphor layer forming method for a plasma display panel using the above phosphor layer forming apparatus, wherein a plurality of small pastes corresponding to the number of nozzles of a nozzle head are applied to a phosphor paste application region of a substrate. The present invention provides a method for forming a phosphor layer of a plasma display panel, wherein the phosphor layer is divided into regions and a phosphor paste is sequentially applied to grooves in each small region.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
In this invention, the nozzle is initially set so as to be deviated by a predetermined distance ΔL from the center of the corresponding two ribs in the direction of one rib. The predetermined distance ΔL is W / 4 when the groove width is W. It is preferably set. By setting in this way, the phosphor paste is applied to the rib on which the nozzle is biased, and the allowable range of positional deviation in the groove width direction between the center of the groove and the nozzle required for that purpose is the maximum value. (± W / 4).
[0009]
The present invention may further include a sensor that detects the position of the rib, and the control unit may set the nozzle position based on a detection result of the sensor.
Further, the sensor may detect the position of the rib based on an alignment mark provided on the substrate.
[0010]
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 light from 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.
[0011]
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.
[0012]
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.
[0013]
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, a strip-like (linear in the figure) partition wall, that is, a rib r is provided.
[0014]
In the substrate assembly 50, an elongated groove-shaped discharge space 30 communicated in the address electrode direction by adjacent ribs r is partitioned for each subpixel (unit light emitting region) EU in the line direction, and the gap size of the discharge space 30 is defined. The
In addition, the barrier ribs meander in the portion corresponding to the non-discharge portion (reverse slit) between the pair of sustain electrodes so that the interval between the barrier ribs is narrowed, or a protrusion for narrowing is attached. A barrier having a height lower than that of the partition wall can be attached to the bottom of the groove. In the present invention, the shape including these shapes is defined as a belt shape.
[0015]
In the elongated groove, phosphor layers 28 of three colors R, G, and B for color display are provided so as to cover the wall surface on the back side including the upper portion of the address electrode A and the side surface of the rib r. It is done.
[0016]
The rib r is made of low-melting glass and is opaque to ultraviolet rays. As a method for forming the ribs r, for example, a process of providing an etching mask by photolithography on a solid film-like low melting point glass layer and patterning by sandblasting is used.
[0017]
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.
[0018]
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.
[0019]
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.
[0020]
In manufacturing such a PDP, the phosphor layer 28 is formed after providing the address electrodes A and the ribs r on the substrate 21 as shown in FIG.
[0021]
Further, the phosphor paste is obtained by dissolving a powdery phosphor and a synthetic resin in a solvent, and the content of the phosphor in the phosphor paste is suitably 60 to 10% by weight.
[0022]
The fluorescent substance contained in the phosphor paste differs depending on the emission color. Specifically, Y ₂ O ₃ : Eu, YVO ₄ : Eu, (Y, Gd) BO ₃ : Eu, Y ₂ O ₃ S: Eu, γ-Zn ₃ (PO ₄ ) ₂ : Mn, (Zn, Cd) S: Ag (above red), Zn ₂ GeO ₂ : Mn, BaAl ₁₂ O ₁₉ : Mn, Zn ₂ SiO ₄ : Mn, LaPO ₄ : Tb , ZnS: (Cu, Al) , ZnS: (Au, Cu, Al), (Zn, Cd) S: (Cu, Al), Zn 2 SiO 4: (Mn, As), Y 3 Al 5 O 12: Ce, Gd ₂ O ₂ S: Tb, Y ₃ Al ₅ O ₁₂ : Tb, ZnO: Zn (more green), Sr ₅ (PO 4) ₃ Cl: Eu, BaMgAl ₁₄ O ₂₃ : Eu, BaMgAl ₁₆ O ₂₇ : Eu _{, BaMgAl 10 O 17: Eu,} ZnS: Ag, Y 2 SiO 3: Ce ( or blue) and the like It is raised.
[0023]
In addition, any resin known in the art can be used as the synthetic resin contained in the phosphor paste. Specific examples include ethyl cellulose, nitrocellulose, acrylic resin, polyvinyl alcohol, and the like, and may further contain a photosensitive resin. On the other hand, examples of the solvent include alcohols, terpineol, butyl carbitol acetate (BCA), butyl carbitol, toluene, and butyl acetate.
[0024]
In the nozzle that discharges the phosphor paste, the nozzle inner diameter is set to be smaller than the rib interval, but the nozzle tip is not inserted between the ribs, so the outer diameter of the tip is the rib interval. May be larger. For example, when the rib interval is 250 to 300 μm, the nozzle preferably has an inner diameter of about 200 to 250 μm and an outer diameter of about 400 to 450 μm. In addition, a nozzle head in which a plurality of (for example, 50 to 150) nozzles are arranged in a line at a pitch that is an integral multiple of the rib pitch can be used.
[0025]
The present invention will be described in detail below based on the embodiments shown in the drawings. This does not limit the invention.
FIG. 2 is an explanatory view showing the structure of the embodiment of the present invention. In this embodiment, the phosphor layer 28 is formed on the substrate 21 having the address electrodes A and the ribs r shown in FIG. An apparatus for applying to the grooves between the ribs r will be described.
[0026]
In FIG. 2, the manipulator 1 is supported by the shaft 2 in the directions indicated by the arrows Y1, Y2 (Y) while the manipulator 1 moves up and down in the directions indicated by the arrows Z1, Z2 (Z-axis direction) while holding the shaft 2 horizontally. A Y-axis moving device 4 that slides in the axial direction), X-axis moving devices 5a and 5b that reciprocate the Z-axis moving devices 3a and 3b vertically (X-axis direction) with respect to the paper surface, and a substrate 21 are placed. A turntable 7 is provided. The nozzle head 51 is fixed to the handle 6 of the Y-axis moving device 4. The Y-axis moving device 4 includes a sensor 66 that detects a positioning mark on the substrate 21, and the turntable 7 is rotated about the shaft 9 by the rotating device 8.
[0027]
A storage tank 52 for storing the phosphor paste is connected to a pressurized tank 56 via tubes 53 and 54 and an electromagnetic valve 55. A compressed air source (for example, an air compressor) 57 is connected to a pressurized tank 56 via a pressure regulator 61, an electromagnetic valve 62, and tubes 58, 59, 60, and a phosphor stored in the pressurized tank 56 from the storage tank 52. The paste is pressurized. The pressurized tank 56 is connected to the nozzle head 51 via an electromagnetic valve 63 and tubes 64 and 65.
[0028]
3 is a front view of the nozzle head 51, and FIG. 4 is a cross-sectional view taken along the line AA in FIG.
In these drawings, the nozzle head main body 80 is provided with a storage chamber 81 for storing the phosphor paste supplied from the tube 65, and 107 bottom surfaces of the main body 80 are communicated with the storage chamber 81 and protrude downward. The nozzles N1 to N107 are arranged in a line at a pitch Pn.
Here, the nozzles N1 to N107 have a length of 15 mm, an outer diameter of 400 μm, and an inner diameter of 210 μm.
[0029]
FIG. 8 is a block diagram illustrating a control unit of the apparatus shown in FIG. The control unit 103 incorporating the microcomputer receives outputs from the keyboard 104 and the sensor 66 for inputting various conditions, and drives the pressure regulator 61, the electromagnetic valves 55, 62, 63, and the X-axis moving devices 5a, 5b. The X-axis motor 105, the Y-axis motor 106 that drives the Y-axis moving device 4, the Z-axis motor 107 that drives the Z-axis moving devices 3a and 3b, and the table motor 102 that drives the rotating device 8 are controlled. And the like are displayed on the CRT 108.
[0030]
In such a configuration, the red phosphor paste is first applied to the grooves between the ribs r of the substrate 21 shown in FIG. In this embodiment, a substrate for a 42-inch PDP (panel size 980 mm × 580 mm) is used as the substrate 21, and 2569 ribs r (FIG. 1) are previously provided in parallel at a pitch Pr on the surface, thereby 2568. A groove of a book is formed.
Here, the rib pitch Pr is set to (1.08 / 3) mm, and the relationship between the nozzle pitch Pn and the rib pitch Pr is Pn = 6Pr.
[0031]
Therefore, the substrate 21 shown in FIG. 2 is placed on the turntable 7 so that the longitudinal direction of the ribs r is perpendicular to the paper surface. As shown in FIG. 6, the phosphor paste application region S of the substrate 21 is divided into four small regions S1 to S4 with the boundary line L as a boundary so that one small region has 6 × 10 7 grooves. The coating process is started from the small area S1. As shown in FIG. 6, positioning marks M <b> 1 and M <b> 2 are printed on the substrate 21 in advance on the outside of the application region S.
[0032]
The control unit 103 receives the activation signal from the keyboard 104, moves the X-axis in response to the output from the sensor 66 for the alignment between the nozzles N1 to N107 and the rib r and the adjustment of the gap between the nozzles N1 to N107 and the rib r. This is performed by driving the devices 5a and 5b, the Y-axis moving device 4, the Z-axis moving devices 3a and 3b, and the rotating device 8, respectively. In this case, the nozzles N1 to N107 are initially set so as to be deviated by W / 4 from the center of the corresponding two ribs r as shown in FIG. 10 (W is the rib interval, that is, the groove width. In the example, W = 290 μm). A part of the red phosphor paste previously stored in the storage tank 52 is supplied to the pressurized tank 56 by the operation of the valve 55, and then the air pressure is supplied from the compressed air source 57 via the pressure regulator 61 and the electromagnetic valve 62. Is applied to the pressurized tank 56. Therefore, when the electromagnetic valve 63 is opened, the phosphor paste is supplied to the nozzle head 51, and the nozzles N1 to N107 start discharging the phosphor paste between the ribs r and to the top of the right rib r as shown in FIG.
[0033]
At the same time, after the nozzle head 51 is advanced from the front end to the rear end of the rib r by the X-axis moving devices 5a and 5b, the electromagnetic valve 63 is closed and the discharge of the nozzles N1 to N107 is stopped. Thereby, the phosphor paste is applied to the 107 grooves with the pitch Pn, that is, the pitch 6Pr over the entire length. This completes the process indicated by the arrow (1) in FIG.
[0034]
Next, the Y-axis moving device 4 moves the nozzle head 51 by 3 Pr in the Y2 direction (FIG. 2). Next, while opening the electromagnetic valve 63 and discharging the phosphor paste from the nozzles N1 to N107, the nozzle head 51 is retracted from the rear end to the front end of the rib r by the X-axis moving devices 5a and 5b. Is closed to stop the discharge of the nozzles N1 to N107. This completes the process indicated by the arrow (2) in FIG.
[0035]
By repeating the application process as indicated by arrows (3) to (8) in FIG. 6, the red (R) phosphor paste is applied to all the grooves where the red phosphor layer is to be formed. . And the side view of each boundary (B section of FIG. 6) of small area | region S1-S4 becomes like FIG. In FIG. 7, the applied paste layers P1 to P107 are formed by nozzles N1 to N107, respectively. Next, the phosphor pastes for green (G) and blue (B) are applied in the same manner using the same apparatus as in FIG. 2, and the phosphor pastes of three colors (R, G, B) for the substrate 21 are applied. The coating operation is finished.
[0036]
In this case, the side view at the B portion of each boundary L of the small regions S1 to S4 in FIG. 6 is as shown in FIG. 9, and the paste layers P1 and P107 on both sides of the boundary L run on the top of the right rib. Is formed. Accordingly, since the ribs on the paste layer do not vary from side to side at the boundary L, display unevenness of the PDP, that is, uneven stripes does not occur.
[0037]
As described above, in the present invention, in order to make sure that the paste layer runs on only the specific rib (right rib), the positions of the nozzles N1 to N107 are offset by W / 4 from the center of the groove as shown in FIG. This is because of the following reasons.
[0038]
As shown in FIG. 11, when the phosphor paste P starts to be ejected from the nozzle N1, the phosphor paste P becomes spherical at the tip of the nozzle due to surface tension, and its diameter becomes more than the interval between the two ribs r. Therefore, in order to make the phosphor paste P ride on one rib r, it is necessary that the center of the nozzle N1 is set to be biased to the rib side by at least ΔL. However, if ΔL is increased as shown in FIG. 12, there is a risk that the phosphor paste P will move over the rib r and move to the adjacent groove, and therefore the center of the nozzle N1 is the inner side (inner wall surface) of the rib r. Cannot be exceeded. Accordingly, the allowable range of ΔL is 0 <ΔL <W / 2, and the center of the nozzle N1 is initially set with a deviation of W / 4 from the center of the corresponding two ribs.
[0039]
After the nozzle N1 starts moving, the phosphor paste P does not transfer from one rib r to the other rib r even if the nozzle N1 slightly deviates from the allowable range as shown in FIG.
As described above, the example in which the phosphor paste is continuously applied in the long and narrow groove formed between the strip-shaped ribs has been described. When phosphors of the same color are arranged, it is also possible to discharge phosphor paste continuously or intermittently to the row and apply the phosphor to the recesses in the row.
[0040]
【The invention's effect】
According to the present invention, even if the coating operation is performed by dividing the coating area on the substrate corresponding to the size of the nozzle head, display unevenness does not occur at the boundary of the coating area. Can be improved.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a configuration of a main part of a PDP according to the present invention.
FIG. 2 is a configuration explanatory view showing an embodiment of the present invention.
FIG. 3 is a front view of a nozzle head according to the present invention.
4 is a cross-sectional view taken along the line AA in FIG. 3;
FIG. 5 is an explanatory view showing a phosphor paste application state of the present invention.
FIG. 6 is a plan view of a substrate according to the present invention.
7 is an enlarged side view of a portion B in FIG. 6. FIG.
FIG. 8 is a block diagram showing a control unit of the present invention.
9 is an enlarged side view of a portion B in FIG. 6. FIG.
FIG. 10 is an explanatory diagram showing a positional relationship between a nozzle and a rib in the present invention.
FIG. 11 is an explanatory diagram showing a positional relationship between a nozzle and a rib in the present invention.
FIG. 12 is an explanatory diagram showing a positional relationship between a nozzle and a rib in the present invention.
FIG. 13 is an explanatory diagram showing a positional relationship between a nozzle and a rib in the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Manipulator 2 Shaft 3a Z-axis moving device 3b Z-axis moving device 4 Y-axis moving device 5a X-axis moving device 5b X-axis moving device 6 Handle 7 Turntable 8 Rotating device 9 Axis 51 Nozzle head 52 Accommodating tank 53 Tube 54 Tube 55 Electromagnetic valve 56 Pressurized tank 57 Compressed air source 58 Tube 59 Tube 60 Tube 61 Pressure regulator 62 Electromagnetic valve 63 Electromagnetic valve 64 Tube 65 Tube 66 Sensor 80 Main body 81 Storage chamber N1 Nozzle N2 Nozzle N3 Nozzle N106 Nozzle N107 Nozzle

Claims (6)

An apparatus for forming a phosphor layer by applying a phosphor paste to a groove formed by a plurality of ribs provided on a surface of a substrate, and having a mounting table on which the substrate is placed and a nozzle for discharging the phosphor paste Nozzle head, supply unit for supplying phosphor paste to the nozzle head, X-direction moving unit for relatively moving the nozzle head and the mounting table so that the nozzle head moves parallel to the rib, and the nozzle head orthogonal to the rib A Y-direction moving unit that relatively moves the nozzle head and the mounting table so as to move, and a control unit that drives and controls the supply unit, the X-direction moving unit, and the Y-direction moving unit. set in the groove to deviate the nozzle when applying the phosphor paste from the center of the corresponding two ribs in the direction of one of the ribs located between, the top of the rib of the phosphor paste to be discharged from the nozzle is only one Phosphor layer forming apparatus of the plasma display panel and controls to be applied in the groove between the two ribs in a state of contact.   2. The phosphor layer forming apparatus for a plasma display panel according to claim 1, wherein the position is a position deviated by W / 4 from the center of the groove, where W is the groove width.   The phosphor layer forming apparatus for a plasma display panel according to claim 1, further comprising a sensor for detecting a position of the rib, wherein the control unit sets the nozzle position based on a detection result of the sensor.   4. The phosphor layer forming apparatus for a plasma display panel according to claim 3, wherein the sensor detects the position of the rib based on an alignment mark provided on the substrate. A phosphor layer forming method of the plasma display panel using a phosphor layer forming apparatus according to claim 1, a phosphor paste coating area of the substrate is divided into small regions of the multiple, to the groove of the small region A phosphor layer forming method for a plasma display panel, wherein the phosphor paste is sequentially applied. The grooves formed by the multiple ribs are arranged at a predetermined pitch on the substrate surface a phosphor paste is applied to a device for forming a phosphor layer,
This corresponds to a nozzle head in which a plurality of nozzles are arranged in a line at a pitch of 3n times the rib pitch, and a width represented by the product of the number of nozzles and the arrangement pitch by moving the nozzle head n times in parallel with the ribs. After applying a phosphor paste of a predetermined color in a predetermined groove of a small area, the apparatus has a configuration in which the phosphor head is applied in small area units by shifting the nozzle head relative to the substrate by an amount corresponding to the small area width. and characterized in that it comprises a mechanism for setting the 1/4 equivalent biased to one of the ribs in the direction positions of the respective groove widths of the center positions of all of the nozzles from the center position of the groove to be coated cloth of the nozzle head A phosphor layer forming apparatus for a plasma display panel.

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