JPH09231908A - Plasma display panel and manufacturing method thereof - Google Patents

Abstract

(57) [Abstract] [PROBLEMS] To realize high-definition and uniform-contrast screen display. In manufacturing a PDP having a partition wall defining a discharge space and a phosphor layer covering a side surface of the partition wall, a polyvinyl alcohol containing a vinyl acetate emulsion as a binder component on a substrate 21 on which the partition wall is formed. The photosensitive phosphor paste 61, which is a system resin, is applied so as to fill the voids between the partition walls, and the applied photosensitive phosphor paste 61 is dried. Air gap 30 using smaller exposure mask 70
The photosensitive phosphor paste 62 in a is exposed to light,
The photosensitive phosphor paste 62 in the unexposed state is removed to form the phosphor layer 28.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a PDP (Plasma D
isplay Panel: Plasma display panel) and a manufacturing method thereof.

A PDP is a thin display device capable of high-speed display and has been attracting attention as a large color display device for high definition. As the PDP market expands, the technology for producing high quality PDPs becomes more important.

[0003]

2. Description of the Related Art A PDP is a display panel having a structure in which a pair of substrates (usually glass plates) facing each other across a discharge space are used as a base. In the PDP, by providing an ultraviolet excitation type phosphor layer in the discharge space, it is possible to display a color different from the emission color of the discharge gas. PDP for color display is R
It has phosphor layers of three colors (red), G (green), and B (blue).

Conventionally, the R, G, B phosphor layers are
A phosphor paste containing powdery phosphor particles as a main component is applied onto a substrate by a screen printing method for each color in order,
It was formed by using a thick film method in which it is baked at once after drying. Particularly, in a PDP having barrier ribs for partitioning the discharge space, there is a forming method in which the phosphor paste is applied so as to fill the voids between the barrier ribs and the discharge space is secured by utilizing the volume reduction of the paste due to firing. It was adopted (Japanese Patent Laid-Open No. 5-299019). According to this forming method, the coating amounts of the phosphor layers of the respective colors can be equalized, and the phosphor layers can be provided relatively easily not only on the inner surfaces between the partition walls but also on the side surfaces of the partition walls. . In order to increase the brightness, it is desirable to maximize the surface area of the phosphor layer.

[0005]

As the definition of PDPs has become higher, the pitch of the partition walls approaches the limit of the pattern accuracy of the screen mask, making it difficult to accurately apply the phosphor paste between the partition walls. Came. If the partition pattern and the mask pattern are misaligned due to factors such as screen mask expansion / contraction and alignment errors,
The upper surface of the partition wall is covered with the phosphor. Since the object color of the non-luminous phosphor is light gray, the presence of the phosphor above the partition walls reduces the display contrast. Further, in a color display PDP, phosphors having different emission colors are mixed with each other due to misalignment of coating, and the color purity of the display color becomes inappropriate. It should be noted that the positional deviation becomes more remarkable as the screen size increases.

In order to solve the problem of such positional displacement, it is considered to use a photosensitive phosphor paste containing a photosensitive material such as polyvinyl alcohol as a binder component. The placement accuracy of the phosphor layer can be increased by applying the photosensitive phosphor paste to the substrate and performing patterning by photolithography. However, there is a problem that the phosphor layer made of a known photosensitive phosphor paste is easily peeled off from the side surface of the partition wall.

An object of the present invention is to realize a screen display with high definition and uniform contrast.

[0008]

A PDP according to the invention of claim 1
Is a photosensitive phosphor paste having partition walls that define a discharge space and a phosphor layer that covers the side surfaces of the partition walls, and the phosphor layer has a polyvinyl alcohol-based resin containing a vinyl acetate emulsion as a binder component. It is a PDP formed by using.

According to a second aspect of the present invention, in manufacturing a PDP having barrier ribs for partitioning a discharge space and a phosphor layer covering side surfaces of the barrier ribs, the barrier ribs are formed on a substrate on which the barrier ribs are formed. The photosensitive phosphor paste is applied so as to fill the voids between them, and after the applied photosensitive phosphor paste is dried, the plan view dimension of the light transmitting portion is smaller than the voids using an exposure mask, and The photosensitive phosphor paste in the gap is exposed to light to remove the non-exposed photosensitive phosphor paste to form the phosphor layer.

According to the third aspect of the present invention, the arrangement state of the substrate is set such that the photosensitive phosphor paste faces downward during the drying of the photosensitive phosphor paste. The method of the invention of claim 4 is to irradiate the photosensitive phosphor paste with scattered light during the exposure.

According to a fifth aspect of the invention, as the photosensitive phosphor paste, a paste containing a polyvinyl alcohol resin containing a vinyl acetate emulsion as a binder component is used.

By using the photosensitive phosphor paste, patterning by photolithography can be performed, so that the arrangement accuracy of the phosphor layer can be improved. In particular, when a paste containing a polyvinyl alcohol-based resin containing a vinyl acetate-based emulsion as a binder component is used, the adhesiveness and flexibility are increased by the vinyl acetate-based emulsion, so that the phosphor layer covering the side surface of the partition wall is formed. It becomes difficult to peel off.

When the photosensitive phosphor paste filling the voids between the barrier ribs is dried, the volume of the paste is reduced and voids are generated again between the barrier ribs. This ensures the discharge space. If the coating layer is directed downward during drying, the coating layer hangs down along the partition wall due to its own weight, and the thickness of the coating layer covering the side surface of the partition wall increases. Inversion of the upper and lower surfaces of the substrate may be repeated in order to equalize the thickness of the coating layer.

When selective exposure is performed only inside the voids, the unnecessary photosensitive phosphor paste is removed at the time of development, even if the photosensitive phosphor paste is present above the partition walls. When the scattered light is irradiated, the exposure range becomes wider than the light-transmitting portion of the exposure mask by a predetermined amount, so that it is possible to form the phosphor layer extending to the vicinity of the upper end of the partition wall.

[0015]

1 is a block diagram of a PDP 1 to which the present invention is applied.
It is a perspective view which shows the internal structure of. The PDP 1 is a matrix display type AC PDP. On the inner surface of the glass substrate 11 on the front surface side, a pair of sustain electrodes X and Y for generating surface discharge along the substrate surface are arranged line by line. Each of the sustain electrodes X and Y is made of ITO.
It is composed of a wide linear strip transparent electrode 41 made of a thin film and a narrow linear strip bus electrode 42 made of a metal thin film. 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 vapor-deposited on the surface of the dielectric layer 17. Both the dielectric layer 17 and the protective film 18 have translucency. 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. A partition wall 29 having a height of 150 μm and having a linear shape in a plan view is provided between the address electrodes A.
Are provided one by one. The discharge spaces 30 are divided into sub-pixels (unit light emitting regions) EU in the line direction by the partition walls 29, and the gap size of the discharge spaces 30 is defined. Then, the wall surface on the back side including the upper side of the address electrode A and the side surface of the partition wall 29 is covered,
Phosphor layers 28 of three colors of R, G, B for color display are provided. The partition wall 29 is made of low melting glass and is opaque to ultraviolet rays. As a method of forming the partition walls 29, a method of providing an etching mask by photolithography on the solid film low melting point glass layer and patterning by sandblasting is preferable.

A pair of sustain electrodes 12 corresponds to one line of the matrix display, and one address electrode A corresponds to one column. The three columns correspond to one pixel (pixel) EG. That is, one pixel EG is composed of three subpixels EU of R, G, and B arranged in the line direction. The counter discharge between the address electrode A and the sustain electrode Y controls the wall charge accumulation state in the dielectric layer 17. When the sustain pulse is alternately applied to the sustain electrodes X and Y, the sub-pixel E in which a predetermined amount of wall charge exists
Surface discharge (main discharge) occurs at U. The phosphor layer 28 is locally excited by ultraviolet rays generated by surface discharge and emits visible light of a predetermined color. Of this visible light, the light that passes through the glass substrate 11 becomes the display light. Since the arrangement pattern of the barrier ribs 29 is a so-called stripe pattern, the discharge space 30
The portion corresponding to each column in the column is continuous in the column direction across all the lines. The emission colors of the sub-pixels EU in each column are the same.

In manufacturing the PDP 1, the phosphor layer 28
After the address electrode A and the partition 29 are provided on the glass substrate 21, is formed by the following procedure. FIG. 2 is a diagram showing a procedure for forming the phosphor layer 28.

Photosensitive phosphor paste 6 of a predetermined emission color (for example, R) so as to fill the space between the partitions 29.
1 is applied by screen printing [Fig. 2
(A)]. Unlike the conventional case, the partition wall 29 at this stage
There is no problem even if the photosensitive phosphor paste 61 is attached to the upper surface of the. The photosensitive phosphor paste 61 is a mixture of a granular phosphor and a photosensitive material. For example, (Y, Gd) BO ₃ : Eu is used as the R fluorescent substance, Zn ₂ SiO ₄ : Mn or BaAl ₁₂ O ₁₉ : Mn is used as the G fluorescent substance, and 3 (Ba, Mg) O / 8Al
₂ O ₃ : Eu is used.

When the glass substrate 21 is introduced into a heating chamber or the like and the photosensitive phosphor paste 61 is dried, the volume of the photosensitive phosphor paste 61 is reduced and the gaps 30 are formed between the partition walls 29.
a occurs [FIG. 2 (B)]. The dry photosensitive phosphor paste 62 covers the address electrodes A, the upper surface of the glass substrate 21, and the side surfaces of the partition walls 29.

Next, the photosensitive phosphor paste 62 is selectively exposed using the exposure mask 70 [FIG.
(C)]. The size of the transparent portion 70a of the exposure mask 70 in plan view is smaller than the gap 30a. That is, the translucent portion 70a is more than the distance w1 between the upper ends of the adjacent partition walls 29.
Has a small width w2. The form of exposure may be a contact type in which the exposure mask 70 and the partition 29 are arranged close to each other,
A projection type using a stepper exposure device or the like may be used. When the parallel light is used for exposure, the direct irradiation range is substantially the projection range of the transparent portion 70a. However, since the indirect exposure due to the scattered light reflected by the phosphor particles is also added, the actual exposure range is wider than the direct irradiation range. When the exposure wavelength is in the ultraviolet region, the partition 29 functions as a light shield, so that the intensity of irradiation light can be sufficiently increased and the range of indirect exposure can be widened. That is, the photosensitive phosphor paste 62 near the upper end of the partition 29 can be exposed.

After the selective exposure, the photosensitive phosphor paste 62 in the non-exposed state is removed by a developing process [FIG.
(D)]. The phosphor layer 28 of one color is formed by the above procedure. After that, the same operation is repeated, and the remaining phosphor layers 28 of two colors are sequentially formed one by one.

FIG. 3 is a view showing a modified example of paste application. If the photosensitive phosphor paste 61 is locally applied on the glass substrate 21 using the screen mask 50,
The amount of paste used can be reduced as compared with the case where the paste is applied to the entire surface of the glass substrate 21. Since the photosensitive phosphor paste 61 may be attached to the upper surface of the partition 29, the partition 2
The tolerance of the positional deviation between 9 and the screen mask 50 is large. When the application range is a region having a width about the arrangement pitch of the partition walls 29, the amount of paste used is 1/100 of that in the case of the entire surface application.
It becomes 3.

FIG. 4 is a view showing the arrangement of the substrates when the paste is dried. In the initial stage of drying the photosensitive phosphor paste 61, the glass substrate 21 is arranged so that its partition forming surface is the upper surface [FIG. 4 (A)]. When the viscosity of the photosensitive phosphor paste 61 increases to such an extent that the photosensitive phosphor paste 61 does not flow down after a predetermined period has passed, the front and back directions of the glass substrate 21 are reversed. That is, the photosensitive phosphor paste 61 is directed downward [FIG. 4 (B)]. Thereby, the photosensitive phosphor paste 6
1 hangs down along the partition 29 due to its own weight, and the thickness of the photosensitive phosphor paste 61 covering the side surface of the partition 29 increases. The light emitting efficiency is increased by equalizing the entire thickness of the photosensitive phosphor paste 61. The front and back of the glass substrate 21 may be repeated while continuing the drying. In that case,
A substrate supporting device having a reversing function is useful.

FIG. 5 is a diagram showing a modification of exposure. FIG.
If a light source that emits scattered light as in (A) is used for exposure, the direct irradiation range is expanded compared to the case of using parallel light, and the edge of the phosphor layer 28 can be brought closer to the upper end of the partition wall 29. Even when a light source that emits parallel light is used as shown in FIGS. 5B and 5C, an exposure mask 71 in which the exit surface of the light-transmitting portion is processed into a frosted glass shape, or an exposure in which a concave lens shape is processed By using the mask 72, the direct irradiation range can be expanded. Exposure mask 71, 7
The processing method of 2 includes methods such as etching and impurity diffusion.

[0025]

[Examples] 1.8 wt% of diazonium salt was mixed with stirring into a base polymer having a viscosity of 9000 cp consisting of 25 wt% of polyvinyl acetate emulsion, 10 wt% of polyvinyl alcohol (PVA) and water as a dispersion medium, and exposed. It was an emulsion. 20w phosphor for the photosensitive emulsion
t% was mixed to obtain a photosensitive phosphor paste. The photosensitive phosphor paste was dropped on the glass substrate 21, the upper portion of the partition walls 29 was rubbed with a squeegee to fill the voids between the partition walls with the photosensitive phosphor paste, and then a drying treatment was performed at 40 ° C. for 20 minutes.
After drying, use a high-pressure mercury lamp as the light source,
Selective exposure was performed using an exposure mask 70 having a transparent portion with a width of%. 5 minutes after immersion in pure water for 1 minute
After washing for one minute with running water, a phosphor layer 28 of the first color was obtained.
In the same manner, the second and third color phosphor layers 28 were obtained.

When the phosphor content was changed to 10-40 wt%, the thickness of the phosphor layer 28 changed. The greater the phosphor content, the greater the thickness. The content (1
It was confirmed that the paste adhered to the vicinity of the upper end of the partition wall 29 regardless of (0 to 40 wt%). Regarding the photosensitivity, when a paste having a phosphor content of 20 wt% was used, a residual film was observed at a portion receiving an exposure energy of 30 mJ / cm ² . The residual film ratio was 100% in the portion receiving the exposure energy of 300 mJ / cm ² or more.

The glass substrate 21 on which the three-color phosphor layers 28 were formed was irradiated with ultraviolet rays having a wavelength of 245 nm for spectroscopic analysis. It was confirmed that there was no mixed emission color and that there were no phosphors on the upper surface of the partition wall 29.

Two exposure masks having a transparent portion having a width of 50% of the distance between the partition walls were prepared. The light transmitting portion of one exposure mask A is transparent. The transparent portion of the other exposure mask B has a frosted glass shape. Selective exposure by parallel light was performed using each of these exposure masks A and B to form a phosphor layer. When the cross-sectional shapes of the phosphor layers were compared, when the exposure mask A was used, the phosphor layers were formed up to about half the height of the partition walls 29. On the other hand, when the exposure mask B was used, the phosphor layer was formed up to the upper end of the partition 29.

When heat treatment was applied to the phosphor layer formed by using the photosensitive phosphor paste containing no polyvinyl acetate emulsion, PVA was peeled off from the partition wall 29 together with the phosphor particles. No peeling occurred when using a photosensitive phosphor paste containing a polyvinyl acetate emulsion.

A sample obtained by applying a photosensitive phosphor paste having a phosphor content of 20 wt% so as to fill the voids between the partition walls, and then applying a drying treatment at 40 ° C. for 20 minutes with the applied surface facing upward. After the same application, leave the application surface facing up 40
The sample was subjected to a drying treatment at -1 ° C for 1 minute, and subsequently, the front and back of the substrate were inverted and compared with a sample subjected to a drying treatment at 40 ° C for 19 minutes. The thickness of the phosphor layer near the upper end of the partition 29 was about 110% of the other sample in the case where the sample was turned upside down.

[0031]

According to the invention of claim 1, it is possible to realize a high-definition screen display with a uniform contrast.

According to the inventions of claims 2 to 5, it is possible to easily manufacture a PDP capable of displaying a screen with high definition and uniform contrast. According to the invention of claim 3, it is possible to increase the luminous efficiency by thickening the portion of the phosphor layer that covers the side wall of the partition wall.

According to the fourth aspect of the present invention, it is possible to form the phosphor layer extending to the vicinity of the upper end of the partition wall, and it is possible to increase the light emitting area. According to the invention of claim 5, it is possible to form a phosphor layer having good coverage on the side surface of the partition wall and stabilize the display quality.

[Brief description of drawings]

FIG. 1 is a perspective view showing an internal structure of a PDP to which the present invention is applied.

FIG. 2 is a diagram showing a procedure for forming a phosphor layer.

FIG. 3 is a diagram showing a modified example of paste application.

FIG. 4 is a diagram showing a state of arrangement of substrates when a paste is dried.

FIG. 5 is a diagram showing a modified example of exposure.

[Explanation of symbols]

 1 PDP (Plasma Display Panel) 11 Glass Substrate (Substrate) 28 Phosphor Layer 29 Partition Wall 30 Discharge Space 61 Photosensitive Phosphor Paste 70 Exposure Mask 70a Light Transmitting Part

Claims (5)

[Claims] 1. A plasma display panel having a partition wall defining a discharge space and a phosphor layer covering a side surface of the partition wall, wherein the phosphor layer is a polyvinyl alcohol resin containing a vinyl acetate emulsion. A plasma display panel, which is formed by using a photosensitive phosphor paste containing as a binder component. 2. In manufacturing a plasma display panel having barrier ribs for partitioning a discharge space and a phosphor layer covering side faces of the barrier ribs, a gap between the barrier ribs is formed on a substrate on which the barrier ribs are formed. The photosensitive phosphor paste is applied so as to fill the gap, and the applied photosensitive phosphor paste is dried. A method of manufacturing a plasma display panel, which comprises exposing the phosphor paste and removing the non-exposed photosensitive phosphor paste to form the phosphor layer. 3. A method of manufacturing a plasma display panel according to claim 2, wherein the substrate is arranged such that the photosensitive phosphor paste is directed downward during the drying of the photosensitive phosphor paste. 4. The method of manufacturing a plasma display panel according to claim 2, wherein the photosensitive phosphor paste is irradiated with scattered light during the exposure. 5. The method of manufacturing a plasma display panel according to claim 2, wherein a paste containing a polyvinyl alcohol resin containing a vinyl acetate emulsion as a binder component is used as the photosensitive phosphor paste.