CN101221873A - Method of manufacturing lower panel of plasma display panel using X-rays - Google Patents

Abstract

The invention discloses a method for manufacturing a lower panel of a plasma display panel by using X-rays, comprising: preparing a base substrate; forming a barrier rib material layer on the base substrate; scanning X-rays on the barrier rib material layer and defining a barrier rib pattern; and developing the barrier rib material layer to form barrier ribs. A fine-pitch pattern of barrier ribs with high precision can be achieved by using X-rays.

Description

Method of manufacturing lower panel of plasma display panel using X-rays

technical field

The present invention relates to a method of manufacturing a lower panel of a plasma display panel, and more particularly, to a method of manufacturing a lower panel of a plasma display panel in which fine-pitch patterning of barrier ribs can be achieved with high precision.

Background technique

A plasma display panel (PDP) is a flat panel display device that generates images by exciting phosphors with ultraviolet (UV) light generated when a discharge occurs between sustain electrodes formed between an upper substrate and a lower substrate.

FIG. 1 is a schematic diagram showing a conventional alternating current (AC) driving type surface discharge PDP. Referring to FIG. 1 , a plurality of address electrodes 22 and a lower dielectric layer 21 are arranged on a lower substrate 20 such that the address electrodes 22 are buried within the lower dielectric layer 21 . The barrier ribs 24 define a plurality of discharge spaces G disposed on the lower dielectric layer 21 and define the discharge spaces G as individual light emitting regions. The discharge space G is coated with red, green, and blue RGB phosphors 25 . The RGB phosphors 25 are excited by ultraviolet rays generated through plasma discharge to generate visible light, and are arranged in the discharge space G and manipulated to generate static or dynamic images.

An upper dielectric layer 11 and a protective layer 15 are disposed on the upper substrate 10 so as to cover scan and sustain electrode pairs 16 disposed on the upper substrate 10 . The upper dielectric layer 11 accumulates wall charges of the plasma discharge, and the protective layer 15 protects the sustain electrode pair 16 and the upper dielectric layer 11 from sputtering of gaseous ions of the plasma discharge, and simultaneously increases emission efficiency of secondary electrons. An inert gas such as He, Xe, or Ne fills the discharge space G of the PDP at a pressure of about 400 to 600 Torr.

The barrier ribs 24 may be formed in an open type stripe pattern, as shown in FIG. 1, or in a closed type pattern for more efficient discharge. The barrier ribs 24 function to maintain a predetermined distance between the upper substrate 10 and the lower substrate 20 and define the discharge space G. Referring to FIG. The barrier ribs 24 prevent electrical or optical crosstalk between the discharge spaces G to improve image quality (including color purity) and provide regions coated with the phosphor 25 to contribute to the emission luminance of the PDP. Meanwhile, the barrier ribs 24 determine the size of a pixel, which is the smallest unit of an image constituted by the discharge spaces G having an RGB format, and determine the resolution of the image by defining a cell pitch between the discharge spaces G. Thus, the barrier ribs 24 affect image quality and luminous efficiency. As the size of the panel increases and higher-definition images are provided, many studies on barrier ribs have been conducted.

Generally, the barrier ribs are manufactured by screen printing, sandblasting, etching, photolithography using a photosensitive paste, or the like. Here, photolithography using a photosensitive paste is performed as follows. First, a photosensitive paste containing a ceramic barrier rib material is coated on a substrate and dried to obtain a film with a desired thickness. Then, the photosensitive paste is selectively exposed to UV light through an aligned photomask, and developed using a developer to remove uncured portions. Finally, the completed structure is sintered, thereby completing the barrier ribs. During exposure to UV light, the portion of the photosensitive paste exposed to UV light is cured by a polymerization reaction, thereby forming barrier ribs, while the remaining portion of the photosensitive paste shielded by the photomask is not cured, but is decomposed and removed during development .

Photosensitive pastes can include inorganic microparticles and organic materials. UV light may be scattered on the interface between the inorganic microparticles and the organic material, and thus photocuring may occur at a portion of the photosensitive paste adjacent to the targeted photosensitive paste portion. In addition, the amount of UV light provided to the portion of the photosensitive paste near the bottom (or the portion of the photosensitive paste closest to the lower dielectric layer 21 in FIG. Part of the photosensitive paste at the bottom. Thus, as shown in FIG. 1, barrier ribs 24 are wider at the bottom than at the top. When the intensity of the UV light is increased in order to increase the penetration depth of the UV light, the intensity of the scattered light also increases.

Contents of the invention

An aspect of the present invention provides a method of manufacturing a lower panel of a plasma display (PDP), in which fine-pitch patterning of barrier ribs with high precision can be achieved using X-rays.

According to one aspect of the present invention, there is provided a method of manufacturing a lower panel of a PDP, the method comprising: providing a base substrate; forming a barrier rib material layer on the base substrate; patterning the barrier ribs; and developing the layer of barrier rib material to form the barrier ribs.

According to another aspect of the present invention, there is provided a method for manufacturing a lower panel of a PDP, the method comprising: forming a first barrier rib material layer with a first thickness on a base substrate; scanning X-rays to define a first barrier rib pattern; forming a second barrier rib material layer of a second thickness on the first barrier rib material layer; defining a second barrier rib pattern by scanning X-rays on the first and second barrier rib material layers patterning barrier ribs; and developing the first and second layers of barrier rib material to form barrier ribs having different heights.

Additional aspects and/or advantages of the invention will be set forth in and in part will be obvious from the description which follows, or may be learned by practice of the invention.

Description of drawings

These and/or other aspects and advantages of the present invention will become more apparent and easier to understand from the following description of embodiments of the present invention, taken in conjunction with the accompanying drawings, wherein:

FIG. 1 is an exploded perspective view showing a conventional plasma display panel PDP;

2 is a flowchart illustrating a method of manufacturing a lower panel of a PDP according to aspects of the present invention;

3A to 3E are vertical sectional views showing detailed processes of the method of FIG. 2;

4 is a vertical sectional view showing a barrier rib fabricated using ultraviolet lithography as a comparative example of the present invention;

FIG. 5 is a diagram showing barrier rib patterns fabricated using the method shown in FIG. 2;

6A to 6C are diagrams showing barrier ribs fabricated under different exposure conditions;

7A to 7D are perspective views illustrating a method of manufacturing a lower panel of a PDP according to an aspect of the present invention;

8 is a perspective view showing an example of a lower panel manufactured according to the method of FIGS. 7A to 7D;

9 is a diagram illustrating a pattern of barrier ribs fabricated using a method according to aspects of the present invention;

10 is a diagram illustrating a method of manufacturing a lower panel according to aspects of the present invention; and

11A to 11D are diagrams illustrating a method of manufacturing a lower panel of a PDP according to aspects of the present invention.

Detailed ways

Embodiments of the invention will now be described in detail, examples of which are illustrated in the accompanying drawings, wherein like reference numerals indicate like elements throughout. The following embodiments are described in order to explain the present invention by referring to the figures. Aspects of the invention may, however, be embodied in different forms and should not be construed as limited to the embodiments set forth herein. When referring to a layer or electrode being disposed or formed "on" another layer or substrate, the term means that the layer or electrode may be formed directly on the other layer or substrate, or that a third layer may be disposed therebetween. Also, the thickness of layers or regions may be exaggerated for clarity.

2 is a flowchart illustrating a method of manufacturing a lower panel of a plasma display panel PDP according to aspects of the present invention. Referring to FIG. 2, a method of manufacturing a lower panel of a PDP according to aspects of the present invention is described herein. A lower substrate of the PDP is first provided (S101), a barrier rib material layer of a desired thickness is formed on the lower substrate (S103), and X-rays are scanned on the barrier rib material layer to define a barrier rib pattern (S105). Then, the barrier rib material layer is developed and patterned (S107). Finally, the completed structure is sintered (S109), thereby completing the lower panel of the PDP.

Hereinafter, the above operations will be described in order in more detail. 3A to 3E are schematic process diagrams illustrating the above-described operations. First, referring to FIG. 3A , the lower substrate 120 of the previously provided PDP is disposed on the stage S. Referring to FIG. The lower substrate 120 may be a glass substrate made of a glass material or a flexible substrate made of a flexible plastic material. At this time, a plurality of electrodes 122 may be arranged on the lower substrate 120 as shown, but may be arranged differently in other respects. The dielectric layer 121 is disposed on the lower substrate 120 so as to cover the electrodes 122 . The electrodes 122 are arranged parallel to each other so as to be separated by a predetermined interval in such a manner that they correspond to regions in which discharge spaces are to be formed. The dielectric layer 121 may be formed by integrally coating a dielectric paste on the lower substrate 120 covering the electrodes 122, but is not limited thereto. According to a desired structure of the PDP, the electrode 122 and/or the dielectric layer 121 may be omitted. For example, in a PDP structure that does not include address electrodes, both electrodes 122 and dielectric layer 121 may be omitted or constructed using other methods.

A barrier rib pattern is formed on the provided lower substrate 120 using X-rays as described above. Hereinafter, a method of forming a barrier rib pattern using X-ray lithography will be described. First, referring to FIG. 3B , a barrier rib material layer 150 is formed to a thickness H on the lower substrate 120 on which the electrodes 122 and the dielectric layer 121 are formed. The thickness H is relative to the top of the dielectric layer 121 . The barrier rib material layer 150 may be formed of a material that exhibits developing properties or development to X-rays (for example, a material that may be cured by X-ray light or heat or dried during evaporation) and thus may be patterned by development. In addition, the barrier rib material layer 150 may be formed by coating a paste-like barrier rib material on the lower substrate 120 (or on the dielectric layer 121 as shown), or alternatively, laminating sheet-shaped barrier ribs on the lower substrate 120. Material.

For example, the barrier rib material layer 150 may be formed of a photocurable organic-inorganic composite material including inorganic microparticles 152 which are basic glass materials to be sintered to form barrier ribs, and various organic materials 151 . In more detail, the inorganic microparticles 152 may be made of glass frit powder, and the inorganic material 151 may include a carrier that makes the inorganic microparticles 152 into a paste, a binder that binds the inorganic microparticles 152, light that promotes curing through a photochemical reaction. Initiator etc. In addition, the organic material 151 may include monomers, dispersants, or other materials.

The thickness H of the barrier rib material layer 150 corresponds to the height of the barrier ribs to be formed. Thus, preferably, the barrier rib material layer 150 should be formed to a sufficient thickness. For example, considering the shrinkage of barrier ribs after sintering, if the barrier rib material layer 150 is formed to a thickness of 160 to 180 μm before sintering, barrier ribs having a height of 120 to 130 μm may be obtained after sintering. After forming the barrier rib material layer 150 to a desired thickness, the barrier rib material layer 150 is cured by drying. The drying of the barrier rib material layer 150 is required when the barrier rib material layer 150 is formed of a paste-like barrier rib material. Thus, drying of the barrier rib material layer 150 may be omitted when an additional process of stabilizing the shape of the barrier rib is unnecessary, for example, when the barrier rib material layer 150 is formed of a sheet-shaped barrier rib material.

Next, referring to FIG. 3C , an X-ray mask 130 having a predetermined pattern is disposed over the barrier rib material layer 150 . At this time, the X-ray mask 130 and the lower substrate 120 having the barrier rib material layer 150 disposed thereon are vertically aligned with each other. The X-ray mask 130 is divided into a transmission area Wmask and a shielding area. As shown in FIG. 3C , when the X-ray mask 130 includes the transparent substrate 131 and the absorber 132 , the absorber 132 is uniformly patterned at least on the surface of the transparent substrate 131 . As such, the transmission area Wmask corresponds to the portion of the transparent substrate 131 not covered with the absorber 132 , and the shielding area corresponds to the portion of the transparent substrate 131 covered with the absorber 132 . The portion of the barrier rib material layer 150 corresponding to the transmission region Wmask (illustrated as 150a) tends to form barrier ribs 155 after photocuring, and the portion of the barrier rib material layer 150 corresponding to the shielding region is not cured and is subsequently removed. . Here, the transparent substrate 131 may be made of a material having good transmittance, so that high-intensity X-rays 100 may be transmitted through the transmission region Wmask. For this, the transparent substrate 131 may be made of a low atomic number material so as to have low absorption. For example, in order to manufacture a large-sized mask, the transparent substrate 131 may be made of a hard glass substrate or a flexible polyimide film. Meanwhile, the absorber 132 may be formed to, for example, a predetermined thickness t so that light transmission through the shielding region does not occur. The absorber 132 may be made of a high atomic number material, such as gold (Au) or tungsten (W), in order to increase absorption. The absorber 132 disposed on the surface of the transparent substrate 131 may be patterned using photolithography or electroplating. Although the X-ray mask 130, transparent substrate 131, and absorber 132 are described for X-rays, the X-ray mask 130, transparent substrate 131, and absorber 132 are not limited thereto, so that any form of electromagnetic radiation can be used for patterning blocking Rib material layer 150 . For example, transparent substrate 131 may be transparent to higher energy electromagnetic radiation and absorber 132 may block its transmission.

Next, the X-rays 100 are scanned on the barrier rib material layer 150 through the X-ray mask 130 , thereby defining a desired pattern on the barrier rib material layer 150 . This operation can be explained in more detail with reference to Figure 3D. That is, when an X-ray source (not shown) emitting X-rays 100 moves in a direction (arrow A) in a state where X-ray mask 130 and lower substrate 120 are aligned, X-rays 100 may be scanned. Alternatively, the X-ray 100 may be scanned from a fixed X-ray source (not shown) while the X-ray mask 130 and the stage S supporting the lower substrate 120 are moved in one direction (arrow B). For convenience, the best method can be chosen and can involve movement of the X-ray source and table S. However, the two methods are identical in that the X-ray 100 scans from one side of the layer of barrier rib material 150 to the opposite side as the X-ray 100 and the layer of barrier rib material 150 move relative to each other. Portions 150 a of the barrier rib material layer 150 exposed to the X-rays 100 are cured by a polymerization reaction, and are left during development thereby forming the barrier ribs 155 . In contrast, portions of the barrier rib material layer 150 not exposed to the X-rays 100 are not cured, and are removed during development, thereby defining discharge spaces. Generally, the X-ray 100 used in pattern definition may have a wavelength of 0.01 to 100 Ȧ but is not limited thereto.

After the pattern definition described above has occurred, development is carried out. During the developing process, a suitable developer, such as an alkaline solution, is applied to the barrier rib material layer 150 to selectively dissolve, disperse, and remove uncured portions of the barrier rib material layer 150 . After the development is completed, only the portion of the barrier rib material layer 150 exposed and cured by the X-rays 100 is left and barrier ribs 155 are formed, as shown in FIG. 3E .

As shown in FIGS. 3A to 3E , due to the optical characteristics of the X-ray 100 , the barrier rib 155 having a predetermined width Wrib may be formed to correspond to the transmission region Wmask of the X-ray mask 130 . Thus, an advantage of the present invention is that it is possible to obtain barrier ribs having a uniform width, or a fine pitch whose width does not vary in the height direction.

FIG. 4 is a cross-sectional view illustrating barrier ribs patterned using UV rays. Referring to FIG. 4 , the barrier rib material layer 150 includes an organic material 151 and inorganic fine particles 152 . When the UV light irradiated on the barrier rib material layer 150 passes through the barrier rib material layer 150, it scatters with a wide angle at the interface of the inorganic microparticles 152 and then diffuses out of the desired barrier rib material layer portion into the adjacent desired area. In the portion of the barrier rib material layer 150 of the barrier rib material layer portion. Portions of barrier rib material layer 150 exposed to scattered light may be undesirably cured. That is, portions of the barrier rib material layer 150 corresponding to the shielding regions of the mask are also exposed to UV rays. For this reason, the width W'rib of the barrier ribs in the height direction is not uniform, but gradually increases along the optical path of the UV light, that is, referring to FIG. The barrier ribs 24 increase in width in the direction of 20.

In addition, the amount of UV light continuously decreases along the light path of the UV light because the light is scattered along the light path. As a result, an insufficient amount of UV rays may be applied into a portion near the bottom of the barrier rib material layer 150 closest to the substrate 120 of FIG. 4 . Considering such a problem, when the intensity of UV light is increased, the intensity of scattering is also increased, and thus the portion of the barrier rib material layer 150 corresponding to the shielding area of the mask is more exposed to the UV light. In contrast, according to aspects of the present invention, X-rays showing less scattering characteristics at the interface of inorganic microparticles are used, and thus occurrence of uncontrollable exposure due to light scattering can be avoided. Accordingly, a barrier rib pattern having a uniform width corresponding to the transmissive region of the mask can be precisely manufactured.

The X-rays having a short wavelength used according to aspects of the present invention have good transmittance enough to penetrate a thick thickness, and thus can penetrate to reach the bottom of the barrier rib material layer. Thus, according to aspects of the present invention, the limitation of the thickness of the barrier rib material layer determined according to the transmittance of light used can be overcome. Furthermore, barrier ribs having a high aspect ratio (ie, wherein the ratio of the height of the barrier rib to the width of the barrier rib is high) can be easily produced by forming the layer of barrier rib material to a thick thickness when desired. In addition, due to the high penetrability of X-rays, the refraction phenomenon caused by the difference in refractive index between the organic material and the inorganic microparticles can be reduced, and thus the precision of the light directionality can be improved, thereby making it possible to realize the barrier rib. Fine-pitch composition. FIG. 5 shows fine-pitch barrier ribs patterned using X-rays, where the upper width of the barrier ribs is about 14 μm.

The amount of energy per unit volume absorbed in the barrier rib material layer (exposure dose, unit: kJ/cm ³ ) is closely related to the precision of the finally obtained barrier rib structure. Thus, when exposing the layer of barrier rib material to X-rays according to aspects of the present invention, it is preferable, but not necessary, to precisely control the dose of X-rays applied to the layer of barrier rib material by quantitative calculations. The dose of X-rays applied to the barrier rib material layer can be optimized by controlling the exposure conditions (eg X-ray intensity, exposure time) in consideration of the penetration depth of the X-rays and the X-ray absorption of the barrier rib material layer. 6A to 6C are diagrams showing barrier ribs fabricated under different exposure conditions. If the exposure time is too short, the barrier ribs are not properly formed because the layer of barrier rib material is not sufficiently cured due to lack of exposure, as shown in Figure 6A. On the contrary, if the exposure time is too long, as shown in FIG. 6C, defects (such as cavities or cracks) are generated in the completed barrier ribs, and the barrier ribs corresponding to the shielding regions of the X-ray mask Portions of the layer of material are also exposed to X-rays, thereby causing curing of portions of the layer of barrier rib material corresponding to shielded regions of the X-ray mask. However, the barrier ribs fabricated with a suitable exposure time have a smooth surface, as shown in FIG. 6B.

Referring again to FIGS. 3A to 3E , the barrier rib material layer pattern obtained through the above pattern definition and development is sintered. For this, the barrier rib material layer pattern is heated to a high temperature close to the melting point of the inorganic fine particles 152 (eg, glass frit) contained in the barrier rib material layer pattern, so that the inorganic fine particles 152 are melted and sintered, and at the same time, removed The organic material 151 included in the rib material layer pattern is blocked.

According to aspects of the invention, the formation of barrier ribs using X-ray lithography is shown. However, if the barrier rib material layer can be patterned using X-rays, the formation method of the X-ray based barrier ribs is not limited to the above methods, and the technical principles can be applied to various methods according to aspects of the present invention. For example, instead of using an exposure mask, an optical path of X-rays may be controlled according to a barrier rib pattern. In this way, a desired pattern can be defined on the layer of barrier rib material. This can be achieved by manipulating the X-ray gun with an X-Y table movable in a biaxial direction.

7A to 7D are perspective views illustrating a method of manufacturing a lower panel of a PDP according to an aspect of the present invention. As mentioned above, X-rays are used to define the desired pattern on the layer of barrier rib material, but so-called stepped barrier rib patterns, i.e. barrier ribs in which different positions of the barrier ribs have different heights, are formed using two operations: the first pattern defines and the second pattern defined.

Hereinafter, various aspects of the present invention will be described in more detail. First, referring to FIG. 7A, the lower substrate 120 of the PDP provided in advance is placed on the stage S. Referring to FIG. At this time, a plurality of electrodes 122 and a dielectric layer 121 arranged to cover the electrodes 122 are formed on the lower substrate 120, but need not be limited thereto. Then, a first barrier rib material layer 150' is formed on the lower substrate 120. Referring to FIG. For example, the first barrier rib material layer 150' may be formed to a predetermined thickness ho by coating a photosensitive paste including inorganic fine particles and various functional organic materials. Here, the thickness ho of the first barrier rib material layer 150' corresponds to the height of the first barrier rib having a relatively lower height among the stepped barrier ribs to be formed. Then, the first barrier rib material layer 150' is dried. Depending on the physical properties of the material of the first barrier rib material layer 150', the drying of the first barrier rib material layer 150' may be omitted. For example, if the sheet of barrier rib material is adhered to the lower substrate, no drying is required.

Next, referring to FIG. 7B , an X-ray mask 130 having a predetermined pattern is aligned over the lower substrate 120 on which the first barrier rib material layer 150' is formed. The X-ray mask 130 may be a mask in which the absorber 132 is patterned on the surface of the transparent substrate 131 . Here, the absorber 132 defines a shielding region that shields X-rays, and a portion of the transparent substrate 131 that is not covered with the absorber 132 defines a transmission region that transmits X-rays. The X-ray mask 130 may be designed to have a transmission region patterned in stripes in one direction (eg, x-axis direction).

Then, a desired pattern is defined on the first barrier rib material layer 150' using the X-ray mask 130 (first pattern definition). At this time, the portion 150b of the first barrier rib material layer 150' corresponding to the transmission region of the X-ray mask 130 is exposed to the X-ray 100 and cured by a polymerization reaction. Portions of the first barrier rib material layer 150' corresponding to the shielding regions of the X-ray mask 130 are not cured. Meanwhile, in this operation, when an X-ray source (not shown) emitting X-rays 100 is aligned in a direction (for example, in the x-axis direction, or the arrow A) When moving, the X-ray 100 can be scanned, or alternatively, when the X-ray mask 130 and the table S supporting the lower substrate 120 move in a direction (such as the x-axis direction, or arrow B), the X-ray 100 can Scan from a stationary X-ray source (not shown).

When the first pattern definition is completed as described above and as shown in FIG. The barrier rib material layer 150 of the first and second barrier rib material layers 150 ′ and 150 ″ is formed on the lower substrate 120 to a thickness h(ho+Δh). At this time, the thickness h of the barrier rib material layer 150 corresponds to the height of the second barrier rib having a relatively higher height among the stepped barrier ribs. After forming the second barrier rib material layer 150" as described above, the barrier rib material layer 150 may be dried if necessary.

Next, referring to FIG. 7D , an X-ray mask 130' is aligned over the layer 150 of barrier rib material. The X-ray mask 130' may be a mask in which the absorber 132' is patterned on the surface of the transparent substrate 131'. The X-ray mask 130' may be designed to have a transmissive region patterned in stripes in one direction (for example, in a z-axis direction). The transmission area may extend so as to cross the transmission area of the X-ray mask 130 used in the definition of the first pattern described above.

Again, the desired pattern is defined on the barrier rib material layer 150 using the X-ray mask 130' (second pattern definition). At this time, the portion 150c of the barrier rib material layer 150 corresponding to the transmission region of the X-ray mask 130' is exposed to the X-ray 100 and cured by a polymerization reaction. At this time, the pattern defined and solidified by the second pattern may overlap the pattern defined and solidified by the first pattern. Meanwhile, in this operation, when the X-ray source (not shown) emitting the X-ray 100 is fixedly aligned with the X-ray mask 130 ′ and the lower substrate 120 in a direction (for example, in the z-axis direction, or the arrow A') When moving, the X-ray 100 may be scanned, or alternatively, when the X-ray mask 130' and the stage S supporting the lower substrate 120 move in one direction (eg, in the z-axis direction, or arrow B'), X-rays 100 may be scanned from a stationary X-ray source (not shown). Although the directions are described and illustrated as x-axis and z-axis directions, the directions are not limited thereto such that the x-axis and z-axis directions need not be perpendicular but only need to intersect or extend to intersect. In addition, a third and/or fourth etc. X-ray pattern defining process may be applied to further define barrier ribs with different heights, so as to obtain multi-step barrier ribs and different patterns of barrier ribs with different heights.

As mentioned above, after performing the two-step X-ray pattern definition process as described above, the barrier rib material layer 150 is developed and sintered, thereby obtaining the stepped barrier ribs 124 as shown in FIG. 8 . Referring to FIG. 8, the stepped barrier rib 124 includes a first barrier rib 124a and a second barrier rib 124b extending to cross each other and having heights h'o and h', respectively, such that the first barrier rib 124a and the second barrier rib 124b are viewed from below. The dielectric layer 121 extends to different heights, wherein the lower dielectric layer 121 is disposed on the lower substrate 120 so as to cover the electrodes 122 . FIG. 9 is a diagram illustrating a stepped barrier rib pattern manufactured according to the above method.

According to aspects of the present invention, the formation of barrier ribs using X-ray lithography is shown, but not limited thereto. For example, selective exposure can be achieved by placing the output of X-rays within a predetermined optical path. More specifically, the layer of barrier rib material is patterned by using an actuator that directs X-rays from an X-ray gun along a controlled path, for example using an X-Y table.

A method of manufacturing a lower panel of a PDP according to aspects of the present invention will now be described with reference to FIG. 10 . According to aspects of the invention in FIG. 10 , the x-ray mask is not required to cover the entire area of the layer of barrier rib material, but the x-ray mask is placed within the optical path of the x-rays and has only enough coverage A small area of the portion of the layer of barrier rib material that is irradiated. That is, referring to FIG. 10 , the lower substrate 120 coated with the barrier rib material layer 150 is placed on the stage S movably installed in one direction, and the X-ray gun (not shown) and the X-ray mask 230 are fixedly Installed above the table S. At this time, the X-ray mask 230 may include a transparent substrate 231 and an absorber 232 adhered on the transparent substrate 231 to define a transmission area and a shielding area. By placing the X-ray mask 230 within the optical path of the X-rays 100 , a predetermined beam of X-rays 100 can be scanned on the barrier rib material layer 150 .

When the stage S on which the lower substrate 120 is disposed moves such that the lower substrate 120 moves at a predetermined speed in one direction, the X-ray 100 scans on the barrier rib material layer 150 through the X-ray mask 230 . Thus, the barrier rib material layer 150 coated on the lower substrate 120 is gradually exposed to the X-rays 100 while moving at a predetermined speed relative to the fixed X-ray gun. That is, when the barrier rib material layer 150 moves relative to the X-rays 100 emitted from the stationary X-ray gun, the X-rays 100 scan from one side of the barrier rib material layer 150 to the opposite side. At this time, the predetermined speed at which the stage S including the barrier rib material layer 150 moves corresponds to the scanning speed of the X-ray 100 , and an exposure dose of the X-ray 100 to the barrier rib material layer 150 is determined. Thus, the predetermined speed at which the table S including the barrier rib material layer 150 moves is preferably optimized in consideration of the penetration depth of the X-rays 100 and the absorbency of the barrier rib material layer 150 . For example, when the barrier rib material layer 150 is formed of a negative type material, the portion 150d of the barrier rib material layer 150 exposed to the X-rays 100 is cured by a polymerization reaction. The exposed portions 150d of the barrier rib material layer 150 are left during development to finally form the barrier ribs.

According to aspects of the present invention, the X-ray mask is formed so as to have an area covering at least an optical path of X-rays and smaller than that of the barrier rib material layer. Thus, when the same exposure effect as above is obtained, reduction in mask manufacturing cost can be achieved. As a result, the manufacturing cost of the PDP is reduced, thereby improving cost and price competitiveness. In particular, for displays of large size (eg, greater than or equal to 40 inches), significant cost reductions are achieved.

11A to 11D are process diagrams illustrating a method of manufacturing a lower panel of a PDP according to aspects of the present invention. Aspects of the invention shown in FIGS. 11A to 11D also provide a method of forming a stepped barrier rib pattern using two operations, first pattern definition and second pattern definition. Furthermore, according to aspects of the invention shown in FIGS. 11A-11D , a smaller X-ray mask is used for multiple pattern definitions thereby reducing the manufacturing cost of the mask.

First, referring to FIG. 11A , the lower substrate 120 of the PDP provided in advance is disposed on the stage S, and a first barrier rib material layer 150' is coated on the lower substrate 120 with a thickness ho. Here, the thickness ho of the first barrier rib material layer 150' corresponds to the height of the first barrier rib having a relatively low height among the stepped barrier ribs to be formed. The first barrier rib material layer 150' may be selectively dried.

Next, referring to FIG. 11B , an X-ray mask 230 is prepared and placed in the optical path of the X-ray 100 . The X-ray mask 230 may include a transparent substrate 231 and an absorber 232 so as to define a transmission area and a shielding area, respectively, and the transmission area of the X-ray mask 230 may be designed to extend in a direction (for example, in the x-axis direction shown) . The X-ray mask 230 is placed in the optical path of the X-rays 100 and has a small area so as to cover only the portion of the first barrier rib material layer 150' that may be exposed to the X-rays 100. Thus, the manufacturing cost of the X-ray mask 230 may be reduced, thereby reducing the manufacturing cost of the PDP and increasing the price competitiveness of the PDP.

Next, a desired pattern is defined on the first barrier rib material layer 150' using the X-ray mask 230 (first pattern definition). That is, the lower substrate 120 coated with the first barrier rib material layer 150' is disposed on the stage S, and an X-ray gun (not shown) and an X-ray mask are fixedly disposed above the stage S. At this time, the X-ray mask 230 is placed in the optical path of the X-ray 100 . The X-ray 100 scans while the stage S supporting the lower substrate 120 moves such that the lower substrate 120 moves in a direction (for example, in the x-axis direction) at a predetermined speed. Here, the moving direction of the lower substrate 120 is parallel to the extending direction of the transmission area of the X-ray mask 230 (eg, the x-axis direction). When the first barrier rib material layer 150' moves at a predetermined speed relative to the X-rays 100 emitted from a fixed X-ray source (not shown), the X-rays 100 are directed toward each other from one side of the first barrier rib material layer 150'. side scan. As the X-rays 100 are scanned, the portion 150e of the first barrier rib material layer 150' corresponding to the transmission area of the X-ray mask 230 is exposed to the X-rays 100 and cured by a polymerization reaction. The portion of the first barrier rib material layer 150' corresponding to the shielding region of the X-ray mask 230 remains as it is until after the second pattern defining process is performed.

After completing the first pattern defining process, a second barrier rib material layer 150" is coated with a thickness of Δh on the first barrier rib material layer 150' having a thickness ho, as shown in FIG. 11C. Thus, comprising The barrier rib material layer 150 of the first and second barrier rib material layers 150' and 150" is formed on the lower substrate 120 with a thickness of h(ho+Δh). At this time, the thickness h of the barrier rib material layer 150 corresponds to the height of the second barrier rib having a relatively higher height among the stepped barrier ribs. After forming the second barrier rib material layer 150", the barrier rib material layer 150 may be dried.

Next, referring to FIG. 11D , an X-ray mask 230' is provided and placed within the optical path of the X-rays 100. Although not required in all aspects, the X-ray mask 230' may include a transparent substrate 231' and an absorber 232' disposed on the transparent substrate 231', thereby defining the X-ray mask 230' in a direction (such as shown in out of the z-axis direction) on the transmission area. The transmission region of the X-ray mask 230' may cross the transmission region of the X-ray mask 230 used in the first pattern defining process. The X-ray mask 230' has a small area so as to cover only a part of the barrier rib material layer 150 under X-ray irradiation or mask the entire X-ray irradiation light path, thereby reducing the manufacturing cost of the mask.

Next, a desired pattern is defined on the barrier rib material layer 150 using the X-ray mask 230'. The lower substrate 120 supporting the barrier rib material layer 150 is arranged on a stage S movably installed in at least one direction (for example, in the z-axis direction), and an X-ray gun (not shown) and an X-ray mask 230′ is fixedly installed above the lower substrate 120 and separated from the lower substrate 120 by a predetermined distance. At this time, the X-ray mask 230' is aligned on the optical path of the X-ray 100. When the stage S on which the lower substrate 120 is disposed operates in a direction (eg, a z-axis direction), the X-ray 100 scans on the barrier rib material layer 150 . When the barrier rib material layer 150 moves relative to the X-ray 100 , the X-ray 100 emitted from the fixed X-ray gun can scan from one side of the barrier rib material layer 150 to the opposite side. As the X-rays 100 are scanned, the portion 150f of the barrier rib material layer 150 exposed to the X-rays 100 is cured by a polymerization reaction. At this time, the portion 150f exposed and cured through the second pattern defining process may overlap the portion 150e exposed and cured through the first pattern defining process.

When developing and sintering the barrier rib material layer 150 with the pattern defined as described above, the inorganic fine particles of the barrier rib material layer 150 are fused with each other to finally form stepped barrier ribs (see 124 of FIG. 8 ). The stepped barrier ribs include first barrier ribs (see 124a in FIG. 8 ) and second barrier ribs (see 124b in FIG. 8 ) extending to cross each other and having different heights (see h'o and h' in FIG. 8 ), The first barrier rib and the second barrier rib are mutually vertical steps.

According to aspects of the present invention, a desired pattern can be precisely defined on a barrier rib material layer using X-rays having predetermined optical characteristics, and thus fine-pitch and high-resolution patterning of barrier ribs can be achieved with high precision. Furthermore, the X-rays used in pattern definition have high penetration efficiency so that the X-rays can cure barrier rib materials even closest to the substrate. Thus, in order to fabricate barrier ribs with a high aspect ratio, the photosensitive paste can be applied to a desired thickness with reduced process constraints.

Furthermore, according to aspects of the present invention, X-rays exhibit relatively low scattering characteristics within barrier rib materials comprising two or more different compositions. Thus, other optical properties of the barrier rib material, such as the index of refraction, need not be considered when selecting the barrier rib material, thereby reducing manufacturing costs compared to conventional UV lithography using special barrier rib materials.

In addition, according to aspects of the present invention, when an X-ray mask is used for pattern definition, the size of the X-ray mask can be reduced according to the area irradiated by X-rays, thereby reducing manufacturing costs and increasing price competitiveness. In particular, when manufacturing large-sized (for example, greater than or equal to 40 inches) plasma display panels, the manufacturing cost can be significantly reduced.

Although some embodiments of the present invention have been shown and described, those skilled in the art should understand that these embodiments can be changed without departing from the principle and spirit of the present invention, and the scope of the present invention is set forth in the appended defined in the claims and their equivalents.

This application claims priority from Korean Patent Application No. 2006-138906 and Korean Patent Application No. 2006-138907 filed with the Korean Intellectual Property Office on December 29, 2006, the entire contents of which are incorporated herein by reference.

Claims (20)

1. A method of manufacturing a lower panel of a plasma display panel, the method comprising: forming a barrier rib material layer on the provided base substrate; defining a barrier rib pattern by scanning x-rays across the layer of barrier rib material; and The barrier rib material layer having the barrier rib pattern defined by X-rays is developed to form the barrier ribs. 2. The method of claim 1, wherein the layer of barrier rib material comprises a material that develops in response to x-rays. 3. The method according to claim 1, wherein the barrier rib material layer comprises inorganic fine particles and organic materials, the inorganic fine particles are melted by X-rays to form the barrier ribs, and at least part of the organic materials can be removed by X-rays. 4. The method of claim 1, wherein the forming of the barrier rib material layer further comprises coating a paste on the base substrate or laminating a sheet material on the base substrate. 5. The method of claim 1, further comprising providing a base substrate on which a plurality of electrodes are formed. 6. The method of claim 5, further comprising providing a base substrate, forming a dielectric layer to cover the plurality of electrodes, on which layer of barrier rib material is to be formed. 7. The method of claim 1, further comprising drying the layer of barrier rib material prior to defining the barrier rib pattern. 8. The method according to claim 1, wherein the definition of the barrier rib pattern comprises placing a photomask in the optical path of the X-ray, the photomask having a shielding area and a transmission area, and placing the photomask The mold is exposed to X-rays such that the shielding regions shield the layer of barrier rib material from X-rays and the transmissive regions allow transmission of X-rays. 9. The method according to claim 8, wherein said photomask has a small area sufficient to shield the entire optical path of said X-rays, said small area being smaller than said barrier rib material layer. 10. The method according to claim 9, wherein an X-ray source emitting the X-rays and the photomask are arranged at predetermined positions, and the X-rays are scanned while the base substrate is moved in a scanning direction. 11. The method of claim 8, wherein the X-rays travel within a predetermined path so as to define the pattern of barrier ribs. 12. The method of claim 1, further comprising sintering the patterned layer of barrier rib material. 13. The method according to claim 1, wherein said X-rays have a wavelength of 0.01 to 100 Ȧ. 14. The method of claim 1, wherein said developing further comprises removing portions of the barrier rib material layer not exposed to said scanning X-rays. 15. A method of manufacturing a lower panel of a plasma display panel, the method comprising: forming a first barrier rib material layer of a first thickness on the base substrate; defining a first barrier rib pattern by scanning X-rays across the first barrier rib material layer; forming a second barrier rib material layer of a second thickness on the first barrier rib material layer; On said first and second barrier rib material layers, defining a second barrier rib pattern by scanning X-rays; and The first and second layers of barrier rib material having the first and second barrier rib patterns defined by X-rays are developed to form barrier ribs having different heights. 16. The method of claim 15, wherein the definition of the first barrier rib pattern and the definition of the second barrier rib pattern are performed using different photomasks. 17. The method of claim 15, wherein the first barrier rib pattern and the second barrier rib pattern extend in stripes to cross each other. 18. The method according to claim 15, wherein the forming of the first layer of barrier rib material further comprises coating a paste on the base substrate or laminating a sheet material on the base substrate, and the second The formation of the barrier rib material layer further includes coating a paste on the first barrier rib material layer or laminating a sheet material on the first barrier rib material layer. 19. The method of claim 15, further comprising providing the base substrate, the base substrate comprising: lower substrate; address electrodes formed across the lower substrate; and A dielectric layer is formed to cover the lower substrate and the address electrodes. 20. A plasma display panel comprising: an upper substrate and a lower substrate arranged to face each other at a predetermined interval; barrier ribs disposed between the upper and lower substrates so as to define the discharge cells; and scan and sustain electrodes for generating discharges within the discharge cells are formed on the upper substrate, wherein the lower panel includes at least a lower substrate and the barrier ribs are formed by the method of claim 1 .

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