KR19990034467A - Method of forming fluorescent layer in plasma display device - Google Patents

Abstract

The present invention discloses an improved method of forming a fluorescent layer of a PDP.

In the case of forming a fluorescent layer between the partition walls in the reflective PDP, there is a problem that the phosphor slurry remains on the upper surface of the partition wall, thereby causing abnormal light emission. After forming the layer, the shielding layer was decomposed to cleanly cut the fluorescent layer to solve the conventional problems and at the same time improve the productivity of the fluorescent layer formation.

Description

Method of forming fluorescent layer in plasma display device

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the manufacture of plasma display panels (PDPs), and more particularly to a method of forming a fluorescent layer of a reflective PDP.

PDPs using gas discharge phenomena for image display can realize a color image by providing a fluorescent layer. PDPs are classified into transmission type and radial type according to the arrangement of the fluorescent layer and the transmission method of discharge light.

First, a transmissive PDP is shown in FIG. 1, in which two electrodes P1 and P2 filled with a discharge gas intersect electrodes E1 and E2, and pixels are partitioned by a partition B. The illustrated PDP is of alternating current type, with symbols D and T representing the dielectric layer and its protective layer.

In this configuration, the fluorescent layer F is formed on the front substrate P1, so that the discharge light generated in the discharge space between the partition walls B passes through the fluorescent layer F as it is, so that high luminance and high reproducibility can be achieved. It becomes possible.

However, such a transmissive PDP has a thin and uniform color filter in the form of a fluorescent layer, so that it is possible to realize a uniform brightness over the entire surface, and thus it is very difficult to manufacture. Therefore, a practical PDP is generally composed of a reflective type as shown in FIG. It is becoming.

In FIG. 2, the fluorescent layer F is formed on the back substrate P2 side, and the discharge excites the fluorescent layer F projected to the back substrate P2 side and the light is reflected by the front substrate P1 side by reflection. Therefore, the basic luminance is lower than that of the transmission type of FIG.

In addition, since the dielectric layer D must be stacked on the electrode not covered with the fluorescent layer F, that is, the electrode E1 on the front substrate P1 side, the dielectric layer D not only covers the transmission path of the discharge light, but also during the manufacturing process. A protective layer (T) made of ITO or the like which is susceptible to clouding also inhibits light transmission.

Accordingly, in order to properly implement the light emission luminance with the reflective PDP, not only a reflective layer having a high reflectance is required but also the surface area of the fluorescent layer F must be increased, thereby forming a fluorescent layer F having a U-shaped cross section as shown. Although the means of is used, it is not easy for the process to form the fluorescent layer F of the U-shaped cross section by the printing method.

In order to efficiently form the fluorescent layer F having such a U-shaped cross section, the present inventor has proposed a method as illustrated in FIG. 3.

That is, droplets (F ') of phosphor slurry having a predetermined viscosity are dropped on the upper side of the partition wall B by a printing method, and the droplets F' are caused by their own weight. It is filled down between the partitions (B) while riding down the partitions (B) to form the fluorescent layer (F).

This method has been demonstrated in the actual production process that the phosphor layer (F) of the U-shaped cross section can be efficiently formed according to the control of the viscosity of the phosphor slurry and the setting of the drying rate, but the phosphor slurry remains on the upper surface of the partition (B). As a result, problems such as abnormal luminescence interference are easily generated.

Such a problem is inevitably caused as long as the fluorescent layer F is printed on the partition B even if the precipitation method or other multilayer printing method is used, and the fluorescent layer F is fired. Since the layer is not held by weak molecular force such as van der Waals force, it is not possible to use the method of cleaning or polishing, so it is necessary to pay attention to printing so that phosphor slurry does not remain on the upper surface of bulkhead (B). In severe cases, there was no alternative but to discard.

In view of such a conventional problem, an object of the present invention is to provide a method for forming a fluorescent layer so that a phosphor slurry does not remain on an upper surface of a partition wall.

1 is a cross-sectional view showing the configuration of a transmissive PDP;

2 is a cross-sectional view showing the configuration of a reflective PDP;

Figure 3 is a cross-sectional view showing a method of forming a fluorescent layer of the U-shaped cross section for the present application,

4 (A)-(D) are sequential cross-sectional views illustrating the method of the present invention,

5 and 6 are cross-sectional views showing preferred methods of forming the shielding layer of FIG. 4 (A), respectively.

<Description of Symbols for Main Parts of Drawings>

P1, P2: front and back substrates B: bulkhead

F: fluorescent layer F ': phosphor slurry

1: shielding layer 1 ': photosensitive layer

In order to achieve the above object, the present invention forms a shielding layer of a material that can be selectively decomposed with the fluorescent layer on the partition wall, by applying a phosphor slurry on the shielding layer to form a fluorescent layer, the shielding layer It is characterized by decomposing.

According to one feature of the present invention, this selective degradability is thermally decomposable and the shielding layer may be formed of a synthetic resin series which can be thermally decomposed by heating at the time of drying the fluorescent layer.

Then, since no phosphor slurry remains at the top of the partition wall, interference between pixels such as abnormal light emitting diodes can be fundamentally prevented.

EXAMPLE

Such specific features and advantages of the present invention will become more apparent from the following description of the preferred embodiments with reference to the accompanying drawings.

In FIG. 4A, a shielding layer 1 having a selective degradability with the fluorescent layer F is formed on the partition B in accordance with the present invention. Preferably, the shielding layer 1 is formed in a substantially c-shaped cross section so as to cover not only the upper surface of the partition wall B but also a part of both upper sides thereof, and the cross section is a photolithography method described below with reference to FIGS. It can be easily formed by photo lithography.

Here, the selective decomposability of the shielding layer 1 is preferably thermally decomposable, so that the shielding layer 1 can be decomposed in the drying process of the fluorescent layer F of FIG. 4C without the need for a separate decomposition process. . To this end, the shielding layer 1 is preferably composed of a synthetic resin series, for example, PVA, so as to be decomposed at a low temperature of 200 ° C. or less, and it is preferable to adjust the content of an additive such as a curing agent to ensure low temperature decomposition.

When the shielding layer 1 is formed in FIG. 4A, the fluorescent layer F is formed on the shielding layer 1 in FIG. 4B. The phosphor layer F may be formed using not only the above-described drip printing method but also a precipitation printing method or a lamination printing method. Since the residual of the phosphor slurry on the upper surface of the partition B is not a problem, the degree of accuracy of these printing methods is required. Will be significantly lowered to allow for very easy printing. In addition, according to the present invention, a lower but more rapid spray coating method can be used to form the fluorescent layer (F).

When the formation of the fluorescent layer (F) in FIG. 3 (B) is completed, it is dried in FIG. 3 (C), which is generally made by a method of applying radiant heat to an infrared heater so as to have a temperature of 150 to 250 ° C.

At this time, the thermally decomposable shielding layer 1 is decomposed and discharged as a gas, and the residual phosphor slurry attached to the upper portion is also removed. Since the removed phosphor slurry is in a dusty state, it may be removed so as not to be settled again in the fluorescent layer (F) by an appropriate air circulation in a dry position.

Then, as shown in FIG. 4D, the upper surface of the partition B and the upper portions of both sides of the partition B become the back surface, thereby cutting the fluorescent layer F cleanly, thereby causing abnormal light emission of the residual phosphor. This can be fundamentally prevented.

5 and 6 show the preferred methods for forming such a shielding layer 1, all of which are basically photolithography, so that the shielding layer 1 includes a photosensitive material as well as the aforementioned resin component.

First, the method illustrated in FIG. 5 is a method of using a negative photosensitive material, that is, a method of removing the exposed part, and covers the entire surface of the back substrate P2 and the partition B as shown in (A1). A resin layer containing a photosensitive material, that is, a photosensitive layer 1 'is formed by a spray coating method or the like.

As shown in (A2), when the light is exposed from the rear surface of the back substrate P2, the partition wall B serves as a mask to selectively expose the photosensitive layer 1 '. At this time, the forming range of the shielding layer 1 can be adjusted by a method such as an elongation rate exposure due to the movement of the exposure light source. When the development by the spraying of washing water is completed, the c-shaped shielding layer 1 is formed on the partition B. To form.

Next, the method of FIG. 6 is a mask exposure method. In the case of using a positive photosensitive material, an opening O of the mask M is formed on the partition B as shown in FIG. In the case of using the photosensitive material, on the contrary, a detailed description thereof will be omitted since it is almost the same as a general mask exposure method except for forming an opening in the hatched portion.

According to the present invention as described above, since no phosphor remains at the top of the partition B, no interference between pixels due to abnormal light emission is generated, and thus, the required degree of the printing method is lowered, and the conventional spraying is impossible. Application of the coating method also becomes possible, and the productivity of the fluorescent layer formation can be greatly improved.

Claims (5)

In the method for forming a fluorescent layer on the substrate between the partition walls of the plasma display device, Forming a shielding layer on a material on the partition wall to be selectively decomposed with the fluorescent layer, After applying a phosphor slurry on this shielding layer to form a phosphor layer, Decomposing the shielding layer A method of forming a fluorescent layer of a plasma display device. The method of claim 1, Selective degradability of the shielding layer is thermally decomposable A method of forming a fluorescent layer of a plasma display device. The method according to claim 1 or 2, The shielding layer is thermally decomposed during the drying of the phosphor slurry A method of forming a fluorescent layer of a plasma display device. The method of claim 1, The shielding layer is composed of a c-shaped cross section covering both the upper surface and the upper side of the partition wall A method of forming a fluorescent layer of a plasma display device. The method according to any one of claims 1 to 4, The shielding layer is formed by applying a photosensitive layer on the partition wall by photolithography A method of forming a fluorescent layer of a plasma display device.