JP2000082400A - Method for forming fluorescent screen of plasma display panel, photo-mask for use in the method, and light source device for exposure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form a fluorescent screen in which color mixing and/or remaining of top part are eliminated regardless of gap likely existing between a work base board and a photo mask. SOLUTION: A fluorescent screen forming layer of photo-sensitive nature is formed at a plurality of ribs, at least between them, which are installed parallel with one another on a work base board 11 and is exposed to light through a photo mask 50 aligned with respect to the work base board 11, followed by development and a baking process so that a fluorescent screen is accomplished, wherein the emitted light from a light source 40 or the diffused light is passed through a light control film 30 of micro-louver structure or a light control film of blind structure in which two layers having different refractive indices are laid in alternation, and the above-mentioned fluorescent screen forming layer is exposed to the output light from the film. Because the exposure can be made with a light based on the emitted or diffused light whose dispersion is finely adjusted, the resultant fluorescent screen is of good workmanship free of color mixing or remaining of top part regardless of gap likely existing between the work base board and photo mask.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention belongs to the technical field of forming a fluorescent screen in a color display plasma display panel (hereinafter referred to as PDP).

[0002]

2. Description of the Related Art In general, a PDP has a structure in which a pair of electrodes arranged regularly on two opposing glass substrates are provided, and a gas mainly composed of Ne, Xe or the like is sealed between the electrodes. Then, a voltage is applied between these electrodes,
By generating a discharge in a minute cell around the electrode, each cell emits light to perform display. In order to display information, regularly arranged cells are selectively caused to emit light. There are two types of PDPs, a direct current type (DC type) in which the electrodes are exposed to the discharge space, and an alternating current type (AC type) in which the electrodes are covered with an insulating layer. And a refresh driving method and a memory driving method.

FIG. 1 shows a configuration example of an AC type PDP. This figure shows the front plate and the back plate separated from each other. As shown in the figure, two glass substrates 1 and 2 are arranged in parallel and opposed to each other, and both become the back plate. The ribs 3 provided on the glass substrate 2 in parallel with each other are held at regular intervals. On the back side of the glass substrate 1 serving as a front plate, composite electrodes composed of a sustain electrode 4 which is a transparent electrode and a bus electrode 5 which is a metal electrode are formed in parallel with each other, and a dielectric layer 6 is covered thereover. The protective layer 7 (MgO layer) is further formed thereon. On the front side of the glass substrate 2 serving as a back plate, address electrodes 8 are formed between the ribs 3 so as to be orthogonal to the composite electrodes and parallel to each other. Are formed, and a phosphor layer 10 is provided so as to cover the wall surface of the rib 3 and the cell bottom surface. The AC type PDP is of a surface discharge type, and has a structure in which an AC voltage is applied between composite electrodes on a front panel to discharge by an electric field leaking into a space. In this case, since the alternating current is applied, the direction of the electric field changes according to the frequency. Then, the phosphor layer 10 emits light by the ultraviolet light generated by the discharge, so that an observer can visually recognize the light transmitted through the front plate.

In the back plate of the above PDP, an address electrode 8 is formed on a glass substrate 2, a dielectric layer 9 is formed so as to cover the address electrode 8 if necessary, and then a rib 3 is formed. It is manufactured by providing a phosphor screen composed of the phosphor layer 10 between the ribs 3. As a method of forming the electrode 8,
A film of an electrode material is formed on the substrate 2 by a vacuum deposition method, a sputtering method, a plating method, a thick film method, and the like, and the film is patterned by a photolithography method, and is patterned by a screen printing method using a thick film paste. Methods and methods are known. The dielectric layer is formed by screen printing or the like, and the ribs 3 are formed by screen printing overprinting or sandblasting. The phosphor screen is formed by a method of selectively filling phosphor pastes of three colors of red (R), green (G), and blue (B) between the ribs 3 by screen printing.

As described above, in order to form a phosphor screen between the ribs, a method of directly filling the gap between the ribs with three color phosphor paste by screen printing and firing the phosphor paste is adopted. However, a large-sized substrate has a problem that it is difficult to produce a screen plate and a dimensional deviation occurs, and a high-definition type has a problem that it is difficult to secure accuracy. Therefore, it has been considered to form a phosphor screen by a photolithography method using a photosensitive phosphor paste or a photosensitive phosphor film. In this method, first, a photosensitive phosphor paste is coated on the ribs formed on the work substrate with a solid and dried, or the photosensitive phosphor film is heated and pressed on the ribs. After forming the phosphor screen forming layer in between, the steps of exposing through a photomask and developing to form the phosphor screen are similarly performed for the phosphor screen forming layers of different colors to form the phosphor screens of three colors. Then, it goes through the procedure of firing. In this photolithography method, an exposure method using parallel light or an exposure method using divergent light or diffused light is being studied.

[0006]

Among the above-mentioned exposure methods, when parallel light is used, there is a problem that it is difficult to form a phosphor screen having a desired shape. In other words, in the above-described process, it is necessary to design a photomask 23 having an opening corresponding to the interval between the ribs 21 to expose the phosphor screen forming layer 22 between the ribs 21 as shown in FIG. Desirably, when the work substrate 11 extends, the top of the rib 21 is exposed as shown in FIG. 3, or the vicinity of one of the wall surfaces is not exposed. As a result, as shown in FIG. 4, a phosphor screen is formed on the top of the adjacent rib 21 or a phosphor screen is not formed on the wall near the top of the rib, and the shape of the phosphor screen becomes left-right asymmetric. . Therefore, the work board 11
Since the elongation of the ribs 21 cannot be taken into account, as shown in FIG.
A photomask is designed so as to protrude between the ribs, so that a phosphor screen is not formed on the top of the rib 21 even if the photomask 23 is displaced. The shape of the surface is left-right asymmetric. Further, when exposure is performed using the photomask 23, the vicinity of the wall surface of the rib 21 becomes difficult to be exposed due to the shadow of the photomask 23. Actually, since the phosphor itself is white, it is scattered and the vicinity of the wall surface is also exposed. However, since the intensity is weak, the phosphor is peeled off during development. Therefore, it is necessary to increase the exposure amount by increasing the intensity of the light source.

On the other hand, an exposure method using divergent light or diffused light can solve the above-described problem that occurs in the case of parallel light. However, in the case of a large-area substrate, the rib and the photomask undulate due to the undulation of the substrate or photomask. Since a portion where the gap of the photomask is open or a portion where there is no gap is in contact, a color mixture of the phosphor and a top residue are generated in a portion where the gap is large. That is, since the spread of the divergent light and the diffused light is too large, the light reaches the portion where the gap between the rib and the photomask is large.

[0008]

In order to solve the above-mentioned problems, according to the present invention, exposure is performed by using light whose divergence angle of divergent light or diffused light is adjusted. Then, by making the opening line width of the photomask narrower than the rib interval and performing exposure with such light, it is possible to form a phosphor screen without color mixing or residual top, regardless of the presence or absence of a gap.

[0009]

DETAILED DESCRIPTION OF THE INVENTION According to the present invention, a photosensitive phosphor screen forming layer is formed between at least a plurality of parallel ribs provided on a work substrate, and the photo-aligned phosphor layer is aligned with the work substrate. A method of forming a phosphor screen by exposing the phosphor screen forming layer through a mask, and developing and firing the phosphor screen to form a phosphor screen. The exposure of the phosphor screen forming layer is performed by light emitted through the control film. Alternatively, the phosphor screen forming layer is exposed by light emitted from a light control film having a blind-like structure in which two layers having different refractive indexes alternately emit divergent light or diffuse light from a light source. It was made.

FIG. 6 is a schematic structural view of a light control film used in the present invention. As shown in the figure, the light control film 30 is a film in which a large number of fine louvers 31 arranged in the same direction are built in. Usually, as shown in FIG. It is a sheet-like material sandwiched by 33. The visible angle is arbitrarily set according to the width and the interval of the louver 31. FIGS. 7A and 7B show a light control film 30 having visible angles of 90 degrees and 60 degrees, respectively.
Is shown. When divergent light or diffused light is applied to the light control film 30, only light in the direction corresponding to the visible angle can pass as shown in FIG. 8, and the spread angle of the divergent light or diffused light is adjusted within a predetermined range.

Another light control film used in the present invention has a blind structure in which two layers having different refractive indexes are alternately arranged. Specifically, when light is incident on the light control film, the light is scattered due to reflection between layers at a certain angle, and is transmitted without reflection at another angle. When scattered, it looks like a cloudy glass, and when transmitted as it is, it looks like a transparent glass.
The visible angle is arbitrarily set by controlling the inclination of the layers having different refractive indexes.

In order to use divergent light or diffused light as a light source, pass light emitted therefrom through a light control film, and expose the phosphor screen forming layer with the passed light, a photomask with a light control film bonded thereto is used. Alternatively, a light control device in which a light control film is bonded to a front glass plate is used as an exposure light source device. In this case, in a light control film having a micro louver structure, it is necessary that the louver direction of the light control film and the opening direction of the photomask be the same. If two light control films are overlapped so that their louver directions are orthogonal to each other, the adjustment can be made not in a line pattern but in a dot pattern, so that the invention can be applied to the case of a grid-like rib.

FIGS. 9 and 10 show a specific example in which a photomask on which a light control film is bonded is used. FIG. 9 shows a case where divergent light is used. In this case, a large number of light sources 40 arranged at the same level with respect to the work substrate 11 are used,
The work substrate 11 is exposed through a photomask 50 to which the “0” is attached. FIG. 10 shows an example in which diffused light is used. A large number of light sources 40 are combined with a diffuser 41 disposed between the light sources 40 and the work substrate 11, and the light source 40 is emitted and then passes through the diffuser 41. Using the light whose directionality has completely disappeared, and using the photomask 50 to which the light control film 30 is attached,
1 is exposed. The light control film 30 is
In order to prevent contact with the work substrate 11, it is preferable to use the photomask 50 by bonding it to the upper surface. As the light source 40, for example, an ultra-high pressure mercury lamp is used. Also,
If necessary, a reflection plate 42 having a mirror-finished surface made of a metal plate or the like may be provided on the opposite side of the work substrate 11.

FIG. 11 shows a specific example of an exposure light source device in which a light control film is bonded to a front glass plate. This exposure light source device has a large number of light sources 40 for emitting directional light in a row in a housing 43, and a front glass plate 4.
4 is a structure in which a light control film 30 is attached. The divergent light emitted from the light source 40 is adjusted in the spread angle by the light control film 30, and the adjusted light is emitted from the front glass plate 44. This light is used to expose the work substrate through a normal photomask. To do. Housing 43
May be a reflection plate. When diffused light is used, a diffuser may be used as the front glass plate 44.

A preliminary experiment was performed using a photomask on which a light control film having a microlouver structure was bonded. Specifically, as shown in FIG.
To dry film 61 (Tokyo Ohka Kogyo “BF-70”
3)) was evaluated by exposing and developing through a photomask 62 having an opening width of 70 μm. The diffused light is used as the light source, and the photo mask 6 is used.
Comparative experiments were performed between various cases in which various light control films 63 were stuck on the upper surface of No. 2 and cases in which they were not stuck. The gap between the dry film 61 and the photomask 62 was 80 μm,
A 0.4% aqueous sodium carbonate solution was used for development.
Spray development was performed at a pressure of 5 kg / cm ² for 40 seconds.

[0016]

[Table 1]

From the results in Table 1, it is possible to reduce the exposure line width a by using light control films having different visible angles. That is, the spread angle of the diffused light can be suppressed by using the light control film. In addition,
The same effect was obtained when the experiment was performed with divergent light.

In the above preliminary experiment, a light control film manufactured by 3M was used. In addition, a light-shielding screen manufactured by Asahi Kasei Kogyo, which is a light control film having a microlouver structure, and two layers having different refractive indexes were used. It is also possible to use Sumitomo Chemical's Lumisty, which is a light control film having a blind structure alternately arranged.

[0019]

EXAMPLE A phosphor powder 51 composed of Zn ₂ SiO ₄ : Mn
0 parts by weight, 100 parts by weight of hydroxypropylcellulose having an average molecular weight of 60,000, 100 parts by weight of pentaerythritol triacrylate, 10 parts by weight of 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butan-1-one , 0.5 parts by weight of methylhydroquinone and 300 parts by weight of 3-methyl-3-methoxybutanol were kneaded with a three-roll mill to prepare a green photosensitive phosphor paste.

On the other hand, a work substrate having electrodes and ribs formed on a glass substrate was prepared. This substrate has a display size of 42 inches, a glass size of 1000 × 600 mm, and a rib having a width of 30 μm, a height of 80 μm, and a pitch of 1 μm.
60 μm. The phosphor paste was applied to the entire surface of the work substrate. Specifically, it was filled by die coating so as to have a thickness of 20 μm from the bottom of the rib. Thereafter, drying was performed in a clean oven at 110 ° C. for 30 minutes.

On the other hand, a photomask in which the opening width is set to 30 μm with respect to the rib spacing of 130 μm and “LCF-P10OB90” manufactured by 3M as a light control film are prepared. Were made in the same direction and both were laminated.

Then, the photomask having the light control film attached thereto is brought into close contact with a work substrate filled with the phosphor paste, and an exposure device of the type shown in FIG. / Cm ² for contact exposure. The gap at the time of close contact was 0 to 80 μm. Subsequently, a pressure of 1 kg / cm was applied by a spray developing machine.
² , after developing under conditions of 4.5 l / min, 90
Drying was performed at 30 ° C. for 30 minutes. As a result, regardless of the presence or absence of a gap, a phosphor screen free of color mixing and no top residue could be formed.

Next, blue and red photosensitive phosphor pastes were prepared, and the phosphor screens were formed in the same manner for each of them. As for these colors, it was possible to form a phosphor screen with no color mixture or residual top. Was.

[0024]

As described above, according to the present invention,
The divergent light or diffused light is passed through a light control film having a microlouver structure or a light control film having a blind-like structure in which two layers having different refractive indices are alternately arranged, and the light that has passed through the light control film is used to generate a photo. By exposing the photosensitive phosphor paste through a mask, it is possible to expose with light whose divergent light or diffused light is adjusted to be narrower, so that color mixing can be performed regardless of the gap between the work substrate and the photomask. It is possible to form a good phosphor screen with no residual top portion.

[Brief description of the drawings]

FIG. 1 is a structural diagram showing an example of a configuration of an AC type plasma display panel in a state where a front plate and a back plate are separated from each other.

FIG. 2 is a cross-sectional view for explaining an exposure step when a phosphor screen is formed by photolithography.

FIG. 3 is a cross-sectional view for explaining an exposure process in a state where a work mask is extended and a photomask is shifted.

FIG. 4 is a cross-sectional view showing a phosphor screen formed through an exposure process in the state shown in FIG. 3;

FIG. 5 is a cross-sectional view for explaining an exposure step using a photomask in consideration of elongation of a work substrate.

FIG. 6 is a schematic configuration diagram of a light control film having a microlouver structure.

FIG. 7 is an explanatory diagram of a visible angle in a light control film.

FIG. 8 is an explanatory diagram of a spread angle of light that can pass through a light control film.

FIG. 9 is an explanatory view showing a case where divergent light is irradiated in a specific example using a photomask to which a light control film is attached.

FIG. 10 is an explanatory view showing a case where diffused light is irradiated in a specific example using a photomask to which a light control film is attached.

FIG. 11 is an explanatory view showing a specific example of an exposure light source device in which a light control film is bonded to a front glass plate.

FIG. 12 is an explanatory diagram showing a state of a preliminary experiment performed using a photomask to which a light control film is attached.

[Explanation of symbols]

 Reference numerals 1 and 2 Glass substrate 3 Rib 4 Sustain electrode 5 Bus electrode 6 Dielectric layer 7 Protective layer (MgO layer) 8 Address electrode 9 Dielectric layer 10 Phosphor layer 11 Work substrate 21 Rib 22 Phosphor screen formation layer 23 Photo mask 30 Light Control film 31 Louver 32 Louver film 33 Surface film 40 Light source 41 Diffusion plate 42 Reflection plate 43 Housing 44 Front glass plate 50 Photomask 60 Raw glass 61 Dry film 62 Photomask 63 Light control film

Claims (6)

[Claims] 1. A light-sensitive fluorescent screen forming layer is formed between at least a plurality of parallel ribs provided on a work substrate, and the fluorescent light is formed via a photomask aligned with the work substrate. Exposure of the surface forming layer,
In the method of forming a phosphor screen of a plasma display panel, which performs a step of forming a phosphor screen by developing and baking, the divergent light or the diffuse light from the light source is passed through a light control film having a microlouver structure, and the light is emitted by the light. A method for forming a phosphor screen of a plasma display panel, comprising exposing a phosphor screen forming layer. 2. A photomask used in the method for forming a phosphor screen of a plasma display panel according to claim 1, wherein a light control film having a microlouver structure is bonded. 3. An exposure light source device used in the method for forming a phosphor screen of a plasma display panel according to claim 1, wherein a light control film having a microlouver structure is bonded to a front glass plate. Exposure light source device. 4. A photosensitive phosphor screen forming layer is formed between at least a plurality of parallel ribs provided on a work substrate, and the fluorescent light is formed via a photomask aligned with the work substrate. Exposure of the surface forming layer,
In a method for forming a phosphor screen of a plasma display panel, which performs a step of forming a phosphor screen by developing and baking, a light having a blind-like structure in which two layers having different refractive indexes alternately emit divergent light or diffuse light from a light source. A method of forming a phosphor screen for a plasma display panel, comprising exposing the phosphor screen forming layer with light emitted through a control film. 5. A photomask used in the method for forming a phosphor screen of a plasma display panel according to claim 4, wherein the light control film having a blind structure in which two layers having different refractive indexes are alternately arranged. A photomask characterized by being bonded. 6. An exposure light source device used in the method for forming a phosphor screen of a plasma display panel according to claim 4, wherein the light control has a blind structure in which two layers having different refractive indexes are alternately arranged. An exposure light source device comprising a film laminated to a front glass plate.