WO2007132979A1

WO2007132979A1 - Substrate for flat panel display device, method of manufacturing the same, flat panel display device using substrate and method of manufacturing flat panel display device

Info

Publication number: WO2007132979A1
Application number: PCT/KR2007/001443
Authority: WO
Inventors: Jong-Uk Bu; Dong-Chun Kim
Original assignee: Senplus Inc.
Priority date: 2006-05-12
Filing date: 2007-03-23
Publication date: 2007-11-22
Also published as: KR20070109724A; KR100844021B1

Abstract

The present invention relates to a substrate for an emissive type flat display panel device such as a plasma display device and an electroluminescent device and a non-emissive type flat display panel device such as a liquid crystal display device, a fabricating method of the substrate, a flat display panel device using the substrate, and a fabricating method of the flat display panel device. The present invention provides a substrate for a flat panel display device including an anodized layer, wherein the substrate includes a metal having at least one of aluminum and magnesium. In addition, the present invention provides a method of fabricating a substrate for a flat panel display device including: a) providing a metal thin plate including at least one of aluminum and magnesium; and b) forming an anodized layer on the metal thin plate. Further, the present invention provides a flat panel display device using the substrate and a method of fabricating a flat panel display device using the substrate. A substrate of the present invention has advantages in mass production due to a roll-to-roll process and has high flatness, high process compatibility, high thermal radiation and excellent insulation property. Specifically, a substrate of the present invention may be easily applied to a flexible flat panel display device because of its high flexibility. Moreover, a substrate of the present invention has excellent thermal radiation and low weight even for a large-sized substrate.

Description

SUBSTRATE FOR FLAT PANEL DISPLAY DEVICE, METHOD OF MANUFACTURING THE SAME, FLAT PANEL DISPLAY DEVICE USING SUBSTRATE AND METHOD OF MANUFACTURING FLAT PANEL DISPLAY DEVICE Technical Field

[1] The present invention relates to a substrate for a flat display panel device, and more particularly, to a substrate for an emissive type flat display panel device such as a plasma display device and an electroluminescent device and a non-emissive type flat display panel device such as a liquid crystal display device, a fabricating method of the substrate, a flat display panel device using the substrate, and a fabricating method of the flat display panel device.

[2]

Background Art

[3] Recently, with the advance of the information age, devices for converting the electric information into and displaying recognizable images have been rapidly developed. In particular, flat panel display (FPD) devices having a thin profile, light weight and low power consumption are actively being developed as substitutes for cathode ray tube (CRT) devices. For example, liquid crystal display (LCD) devices, plasma display panels (PDP), field emission display (FED) devices and electroluminescent display (ELD) devices have been researched and developed as FPD devices.

[4] Of these FPD devices, liquid crystal display (LCD) devices are widely used as monitors for notebook computers and desktop computers because of their high resolution, high contrast ratio, color rendering capability and superior performance for displaying moving images.

[5] Generally, a FPD device includes a flat display panel as an important element for displaying images. The flat display panel includes two substrates facing each other and luminescence or polarization material layer between the two substrates. An active matrix type display, where a plurality of pixels arranged in a matrix form and are individually driven, are widely used because of their high resolution and superiority in displaying moving images.

[6] FPD devices are classified into an emissive type and a non-emissive type according to a luminescence ability. An electroluminescent display device and a plasma display device belong to the emissive type, and a liquid crystal display device belongs to the non-emissive type. Among the liquid crystal display device, a reflective liquid crystal display device using an ambient light or an artificial light of exterior does not require a backlight unit.

[7] Accordingly, in an emissive type flat display panel device such as an electroluminescent display device and a plasma display device and in a non-emissive type flat display panel device such as a reflective liquid crystal display device, a front substrate adjacent to a user may include a transparent insulating material, while a rear substrate may include an opaque material blocking light.

[8] FIG. 1 is a cross-sectional view showing a reflective liquid crystal display device according to the related art. As shown in FIG. 1, a liquid crystal layer 50 is disposed between first and second substrates 2 and 52 parallel to each other.

[9] A pixel electrode 12 having a relatively high reflectance is formed on an inner surface of the first substrate 2 in each pixel region P, and a common electrode 56 is formed on an inner surface of the second substrate 52. The pixel electrode 12, the common electrode 56 and the liquid crystal layer 50 constitute a liquid crystal capacitor. The alignment direction of molecules in the liquid crystal layer is changed by an electric field generated between the pixel and common electrodes 12 and 56, and the transmittance difference is generated by the alignment direction change. The transmittance difference influences light reflected on the pixel electrode 12.

[10] FIG. 2 is a cross-sectional view showing an organic electroluminescent display device as an example of an electroluminescent display device according to the related art.

[11] As shown, an organic electroluminescent display device includes a first substrate 2, a second substrate 52 and an organic luminescent layer 24 between the first and second substrates 2 and 52. A first electrode 22 is formed on an inner surface of the first substrate 52, and the organic luminescent layer 24 is formed on the first electrode 22. A second electrode 32 is formed on the organic luminescent layer 24. When positive and negative voltages are applied to the first and second electrodes 22 and 32, respectively, light is emitted by energy difference in recombination of an electron and a hole, and images are displayed.

[12] FIG. 3 is a perspective view showing a plasma display device according to the related art. A discharge space C including a fluorescent layer 48 is formed between first and second substrates 2 and 52 facing each other.

[13] A plurality of address electrodes 42 is formed on an inner surface of the first substrate 2, and a first insulating layer 44 is formed on the plurality of address electrodes 42. A partition 46 is formed on the first insulating layer 44. The discharge space C is defined by a gap between partitions and corresponds to the plurality of address electrodes 42. A fluorescent layer 48 is formed in the discharge space C. In addition, X and Y electrodes 62 and 64 are formed on an inner surface of the second substrate 52. The X and Y electrodes 62 and 64 are parallel to a direction crossing the discharge space C, and alternately disposed. A second insulating layer 68 and a protecting layer 70 are sequentially formed on the X and Y electrodes 62 and 64.

[14] Accordingly, the discharge space C is filled with an inert gas and plasma is generated by applying adequate voltages to the address electrode 42, the X electrode 62 and the Y electrode 64. An ultraviolet ray induced from the plasma is changed into a visible ray due to the fluorescent layer 48 and the visible ray is emitted, thereby images displayed.

[15]

[16] As mentioned above, an opaque material may be used for the first substrate 2 of an emissive type flat panel display device such as an electroluminescent display device and a plasma display device and a reflective liquid crystal display device.

[17] A fabrication process of a flat panel display device is performed for a substrate.

Physical and chemical treatments such as cleaning, heating, deposition of thin film for patterning, photolithography and etching are repeated. Glass or quartz has been widely used for the substrate because of its excellent flatness, process compatibility and heat resistance.

[18] However, as the flat panel display device is enlarged according to a user's request, the size of the substrate is also enlarged rapidly. Since the substrate of glass or quartz has a specific thickness for a desired hardness, a weight of the substrate and a production cost are increased. Accordingly, light weight and competitive cost of the other user's request is violated.

[19] In addition, since the substrate of glass or quartz is not flexible, there exists a limitation in storage and transfer. Therefore, development of a flexible substrate is required.

[20] In an organic electroluminescent display device, an effective function of heat radiation is necessary to the first substrate having an organic electroluminescent diode. The substrate of glass or quartz has disadvantages in heat radiation due to a low heat conductance.

[21] Although a stainless substrate of a thin plate shape is introduced as a substitute for the substrate of glass or quartz, stainless has a heat resistance relatively lower than other metals. Further, when the stainless substrate is used, an insulating layer is ne cessary for insulation from the various elements on the substrate. However, there exist disadvantages in adhesion, thermal expansion and resistance to high temperature of the insulating layer. Specifically, there is a limitation in mass production through cheap fabrication process.

[22] Therefore, common utilization of a new substrate having a thin plate shape, a desired hardness, a flexibility, a high heat conductance and a competitive cost for mass production is urgently required for a flat panel display device. [23]

Disclosure of Invention

Technical Problem

[24] To achieve these and other advantages and in accordance with the above purpose, an object of the present invention is to provide a substrate for a flat panel display device as a substitute for a related art substrate of glass or quartz having disadvantages in flexibility, thermal radiation, weight and production cost according to increase in size.

[25] Another object of the present invention is to provide a substrate for an emissive type flat panel display device such as a plasma display penal device and an electroluminescent display device or a non-emissive type flat panel display device such as a reflective liquid crystal display device.

[26] Another object of the present invention is to provide a substrate for a flat panel display device which can protect elements thereon due to a maximization of thermal radiation and is suitable for mass production due to sufficient hardness and light weight even for a large size.

[27] Another object of the present invention is to provide a flat panel display device and a fabricating method thereof where properties are improved by using the substrate.

[28]

Technical Solution

[29] To achieve these and other advantages and in accordance with the purpose of embodiments of the invention, as embodied and broadly described, the present invention provides a substrate for a flat panel display device including an anodized layer, wherein the substrate includes a metal having at least one of aluminum and magnesium. The metal is selected from one of aluminum, aluminum alloy, magnesium, magnesium alloy and aluminum magnesium alloy, the anodized layer includes a plurality of pores, and the plurality of pores are sealed with an insulating material including resin or glass group.

[30] In another aspect, the present invention provides a method of fabricating a substrate for a flat panel display device including: a) providing a metal thin plate including at least one of aluminum and magnesium; and b) forming an anodized layer on the metal thin plate. The method further includes: a') coating a photoresist on the metal thin plate after the step of a) before the step of b); and b') removing the photoresist after the step of b). The method, after the step of b), further includes: c) sealing a plurality of pores in the anodized layer with an insulating material; and d) polishing the anodized layer to be flat. The step of b) includes electrolytically oxidizing the metal thin plate. Each of the steps is performed through a roll-to-roll process where the metal thin plate winding around a first roll is transferred to be the substrate winding around a second roll.

[31] In another aspect, the present invention provides a flat panel display device including: a substrate including an anodized layer, wherein the substrate includes a metal having at least one of aluminum and magnesium and a plurality of pixel regions are defined on the substrate; a switching element in each pixel region; and an organic electroluminescent diode in each pixel region, the organic electroluminescent diode connected to the switching element by one-to-one correspondence. The organic electroluminescent diode includes: a first electrode connected to the switching element; an organic luminescent layer having an electron injection layer, an organic emission layer and a hole injection layer sequentially on the first electrode; and a second electrode on the emitting layer.

[32] In another aspect, the present invention provides a flat panel display device including: a substrate including an anodized layer, wherein the substrate includes a metal having at least one of aluminum and magnesium and a plurality of pixel regions are defined on the substrate; a switching element in each pixel region; and a liquid crystal capacitor in each pixel region, the liquid crystal capacitor connected to the switching element by one-to-one correspondence. The liquid crystal capacitor includes: a pixel electrode connected to the switching element; a common electrode facing the pixel electrode; and a liquid crystal layer between the pixel electrode and the common electrode. The substrate includes a metal line pattern connected to the switching element, wherein the metal line pattern is exposed to an exterior and includes the at least one of aluminum and magnesium, and wherein the anodized layer wraps the metal line pattern.

[33] In another aspect, the present invention provides a flat panel display device including: a substrate including an anodized layer, wherein the substrate includes a metal having at least one of aluminum and magnesium and a discharge space is defined on a surface of the substrate by a groove in the anodized layer having a stripe shape; an address electrode in the anodized layer, the address electrode having a stripe shape and corresponding to the discharge space; a fluorescent layer in the discharge space; and an inert gas filling the discharge space.

[34] In another aspect, the present invention provides a method of fabricating a flat panel display device including: a) providing a metal thin plate including at least one of aluminum and magnesium; b) forming a first photoresist pattern on one surface of the metal thin plate; c) etching the one surface of the metal thin plate to form a discharge space that is defined by a groove between partitions having a stripe shape; d) forming a second photoresist pattern on the other surface of the metal thin plate; e) forming an anodized layer on the metal thin plate and an address electrode in the anodized layer, the address electrode having a stripe shape and corresponding to the discharge space; f) forming a fluorescent layer in the discharge space; and g) filling the discharge space with an inert gas. [35]

Advantageous Effects

[36] The present invention solves problems such as increase in weight and production cost of substrate as a flat panel display device is increased. Since the substrate according to the present invention has superiority in flexibility, flatness and thermal radiation to a substrate of glass or quartz, the substrate according to the present invention is used for an emissive type flat panel display device such as a plasma display panel device and an electroluminescent display device or a non-emissive type flat panel display device such as a reflective liquid crystal display device. Moreover, the substrate according to the present invention is used for a solar cell or a radio frequency identification (RFID). Brief Description of the Drawings

[37] FIG. 1 is a cross-sectional view showing a reflective liquid crystal display device according to the related art.

[38] FIG. 2 is a cross-sectional view showing an organic electroluminescent display device as an example of an electroluminescent display device according to the related art.

[39] FIG. 3 is a perspective view showing a plasma display device according to the related art.

[40] FIG. 4 is a cross-sectional view showing a substrate for a flat panel display device according to the present invention.

[41] FIG. 5 is a block diagram showing a fabricating method of a substrate according to the present invention.

[42] FIGs. 6 to 9 are cross-sectional views showing a method of fabricating a substrate according to the present invention.

[43] FIG. 10 is a cross-sectional view showing a method of forming the substrate according to the present invention.

[44] FIG. 11 is a cross-sectional view showing a reflective liquid crystal display device using a substrate according to the present invention.

[45] FIG. 13 is a cross-sectional view showing an alternating current (AC) type plasma display panel device using a substrate according to the present invention.

[46] FIGs. 14 to 18 are cross-sectional views showing a method of fabricating a first lower substrate according to the present invention.

[47] FIG. 19 is a cross-sectional view showing an organic electroluminescent display device using a substrate according to the present invention. [48]

Best Mode for Carrying Out the Invention

[49] Hereinafter, reference will now be made in detail to the preferred embodiments of the invention, examples of which are illustrated in the accompanying drawings.

[50] FIG. 4 is a cross-sectional view showing a substrate 100 for a flat panel display device according to the present invention. An anodized layer 104 is formed on a base plate 102 of metal. The base plate 102 may include at least one of aluminum (Al) and magnesium (Mg). For example, aluminum alloy, magnesium, magnesium alloy and aluminum magnesium alloy may be used for the base plate 102. The thickness of the base plate 102 may be controlled in a range equal to or greater than 0% of the thickness of the substrate 100 and smaller than 100% of the thickness of the substrate 100 according to purpose. In addition, the thickness of the anodized layer 104 may also be controlled in a range greater than 0% of the thickness of the substrate 100 and equal to or smaller than 100% of the thickness of the substrate 100 according to purpose.

[51] The anodized layer 104 may be formed on one surface of the base plate 102 or on both surfaces of the base plate 102. Further, the anodized layer 104 may be formed on a portion of one surface of the base plate 102 or on an entire one surface of the base plate 102. The anodized layer 104 may be formed using an electrolytic oxidation. Although an anodized layer through an electrolytic anodization for a metal including aluminum or magnesium has a rough and porous surface having a plurality of pores, a plurality of pores 106 in the anodized layer 104 is sealed with an insulating material 120 and the surface is polished to be flat in the substrate 100 as shown in magnified view of FIG. 4.

[52] As a result, the substrate 100 according to the present invention includes the base plate 102 of a metal including at least one of aluminum and magnesium and the anodized layer 104 on the base plate 102. Since the anodized layer 104 is formed through an electrolytic oxidation, the anodized layer 104 has high adhesion force to the base plate 102. Specifically, the substrate 100 has excellent electric insulation due to the seal of the insulating material 120 in the plurality of pores 106 and the surface of the substrate 100 is polished to have excellent flatness.

[53] In addition, since the substrate 100 according to the present invention includes aluminum or magnesium having high flexibility and thermal radiation, the substrate 100 has advantages in storage, transfer and thermal radiation as a substrate for a large- sized flat panel display device.

[54]

Mode for the Invention [55] The fabricating process of the substrate 100 according to the present invention will be illustrated hereinafter.

[56] FIG. 5 is a block diagram showing a fabricating method of a substrate according to the present invention. Referring to FIGs. 4 and 5, a metal thin plate including at least one of aluminum and magnesium is prepared in a first step stl. The metal thin plate has various thicknesses according to purpose. Considering the inherent property of aluminum and magnesium such as malleability and ductility, the metal thin plate may be easily obtained by a method such as a rolling.

[57] Next, an initial anodized layer is formed on a surface of the metal thin plate in a second step st2.

[58] The initial anodized layer may be formed through an electrolytic oxidation of the metal thin plate. For example, after the metal thin plate may be immersed in an anodizing solution, a positive voltage is applied to the anodizing solution to form the initial anodized layer on a top surface of the metal thin plate. The anodizing solution may include one of sulfuric acid, oxalic acid, a malonic acid, boric acid, phosphoric acid and chromic acid. The base plate 102 having a thickness equal to or greater than 0% of the thickness of the substrate of and smaller than 100% of the thickness of the substrate and the initial anodized layer having a thickness greater than 0% of the thickness of the substrate and equal to or smaller than 100% of the thickness of the substrate are obtained by controlling reaction condition such as the applied voltage, the concentration of the anodizing solution, the process time for electrolytic oxidation and the temperature.

[59] After the first step stl and before the second step st2, an additional step stl' of coating a photoresist may be performed to form the anodizing layer 104 on one surface or both surfaces of the base plate 102, or on an entire one surface or a portion of one surface of the base plate 102. When the metal thin plate is anodized with the photoresist, a portion having the photoresist is not anodized and the other portion without the photoresist is anodized to have the initial anodized layer. After the second step st2, the photoresist is removed and the base plate 102 corresponding to the photoresist is exposed in a subsequent step st2'.

[60] Next, the plurality of pores 106 in the initial anodized layer are sealed in a third step st3. For example, an insulating material of a liquid phase may be coated on a surface of the initial anodized layer or the initial anodized layer may be immersed in a solution of insulating material to fill the plurality of pores 106 with an insulating material 120. The insulating material 120 may include resin or glass group.

[61] Sequentially, a hardening step of the insulating material 120 in the plurality of pores

106 may be performed and a polishing may be performed in a fourth step st4. The polishing may be performed through a method of brushing and grinding a surface with materials of grain or powder phase having high hardness. As a result, the substrate having the metal base plate of at least one of aluminum and magnesium and the anodized layer is obtained.

[62]

[63] FIGs. 6 to 9 are cross-sectional views showing a method of fabricating a substrate

100 according to the present invention. In FIG. 6, the meal thin plate 102a including at least one of aluminum and magnesium is prepared and the photoresist 130 is formed on a rear surface of the metal thin plate 102a. In FIG. 7, the metal thin plate is anodized to form the initial anodized layer 104a on the base plate 102. In FIG. 8, the photoresist is removed and the plurality of pores 106 in the initial anodized layer 104a is sealed with the insulating material of liquid phase to form the anodized layer 104b. In FIG. 9, the surface of the initial anodized layer 104a is polished to form the anodized layer 104 having a flat surface.

[64]

[65] The steps of coating and removing the photoresist stl' and st2' and the step of forming the initial anodized layer st2 may be added or modified according to purpose of the present invention. Since the above illustrations and drawings are an introduction to a fabrication process of a substrate 100 according to an embodiment of the present invention, the present invention is not limited to the above illustrations and drawings. The exemplary embodiments will be illustrated in detail hereinafter.

[66]

[67] Since the substrate 100 includes aluminum or magnesium, the substrate 100 may be formed through a roll-to-roll process. FIG. 10 is a cross-sectional view showing a method of forming the substrate according to the present invention. The roll-to-roll process, which is referred to as a rill-to-rill process, is a continuous process for mass production of thin plate product. In the roll-to-roll process, a fabrication process is completed while the basic material winding around one roll is transferred to the other roll.

[68] As shown in FIG. 10, accordingly, the metal thin plate 102a as a basic material winding around a first roll 142 is transferred to a second roll 144 through a coating unit 150 of the photoresist, an electrolytic oxidizing unit 152 for an electrolytic oxidation, a removing unit 154 of the photoresist, a sealing unit 156 of the insulating material for the plurality of pores in the initial anodized layer and a polishing unit 158 for the initial anodized layer. As a result, a completed substrate 100 is winding around the second roll 144.

[69] For example, the coating unit 150 may include a slit nozzle to coat the photoresist on the metal thin plate 102a, and the electrolytic oxidizing unit 152 may include a bath having an anodizing solution so that the metal thin plate 102a can be dipped in and move through the bath. In the removing unit 154, a specific solution may be sprayed to remove the photoresist. In the sealing unit 156, the insulating material of liquid phase may be sprayed to fill the plurality of pores in the initial anodized layer. The polishing unit 158 may include a specific polishing means for grinding and planarizing the surface of the initial anodized layer.

[70]

[71] The substrate 100 according to the present invention has an optimum property for an emissive type flat panel display device such as a plasma display panel device and an electroluminescent display device or a non-emissive type flat panel display device such as a reflective liquid crystal display device. Since the substrate 100 includes the metal base plate 102 having at least one of aluminum and magnesium and the anodized layer 104 on the base plate 102, a desired hardness and a light weight are obtained even for a large-sized substrate. In addition, the substrate 100 has a high thermal radiation due to a high heat conductance. Further, since the plurality of pores 106 in the anodized layer 104 are sealed with the insulating material 120, penetration of external oxygen and moist is prevented and the electric insulation of the elements on the substrate is effectively obtained. Specifically, the surface of the anodized layer 104 has a high flatness due to the polishing step. Moreover, since the substrate 100 according to the present invention has a high flexibility, the substrate 100 may be applied to a flexible flat panel display device. (FIG. 4)

[72]

[73] Hereinafter, embodiments of the present invention will be illustrated in detail.

[74]

[75] FIG. 11 is a cross-sectional view showing a reflective liquid crystal display device using a substrate 100 according to the present invention. The liquid crystal display device uses an optical anisotropy and polarization of liquid crystal molecules. In FIG. 10, the substrate 100 according to the present invention is used as a first substrate, which is referred to as an array substrate. Here, the first substrate has the same reference number as the substrate, and the first substrate 100 includes a metal base plate 102 having at least one of aluminum and magnesium and an anodized layer 104.

[76] Although not shown in FIG. 11, a gate line and a data line are formed on the anodized layer 104 over the first substrate 100. The gate line and the data line cross each other to define a pixel region P, and a thin film transistor T is formed at a crossing of the gate line and the data line. A pixel electrode 152 having a high reflectance is formed in each pixel region P and the thin film transistor T is connected to the pixel electrode 152 in one-to-one correspondence.

[77] Although not shown in FIG. 11, a second substrate, which is referred to as a color filter substrate, faces and is spaced apart from the first substrate 100. A liquid crystal layer is disposed between the first and second substrates 100 and not shown. A color filter layer and a common electrode are sequentially formed on an inner surface of the second substrate. The pixel electrode 152, the common electrode (not shown) and the liquid crystal layer constitute a liquid crystal capacitor, and the alignment direction of liquid crystal molecules is controlled by an electric field generated between the pixel electrode 152 and the common electrode. Accordingly, images are displayed due to transmittance difference.

[78] The first substrate 100 may be easily applied to fabrication process of a liquid crystal display device because of high insulation, high flexibility, light weight even for a large size and high thermal radiation.

[79]

[80] FIG. 12 is a cross-sectional view showing an electroluminescent display device using a substrate 100 according to the present invention. The electroluminescent display device emits light through recombination of electron and hole. Since the organic electroluminescent material emits visible light including blue light and emits light having a high brightness even for a low operation voltage, the organic electroluminescent display device has been widely used. The substrate 100 according to the present invention is used as a first substrate of the electroluminescent display device. The first substrate 100 includes a metal base plate 102 having at least one of aluminum and magnesium and an anodized layer 104 on the base plate 102. A pixel region P in matrix is defined on the anodized layer 104, and a switching element including at least one thin film transistor T and an organic electroluminescent diode connected to the switching element are formed in each pixel region P.

[81] The organic electroluminescent diode includes a first electrode 154, an organic luminescent layer 156 and a second electrode 164 sequentially formed on the first substrate 100. When negative and positive voltages are applied to the first and second electrodes 154 and 164, respectively, light is emitted due to an energy difference from recombination of an electron and a hole, and images are displayed.

[82] The organic luminescent layer 156 emitting specific colored light, for example, red, green and blue colored light, may include an electron injection layer 158, an organic emission layer 160 and a hole injection layer 162.

[83] Although not shown in FIG. 12, a second substrate faces and is spaced apart from the first substrate 100.

[84] When the organic electroluminescent display device has a top emission type, the first electrode 154 may include a metallic material having a work function lower than a work function of the second electrode 164 and the second electrode 164 may include a transparent conductive material having a work function higher than a work function of the first electrode 154. Alternately, the second electrode 164 may be formed to have a thin thickness transmitting light regardless of work functions of the first and second electrodes.

[85] Further, the first substrate 100 may be easily applied to fabrication process of an organic electroluminescent display device because of high insulation, high flexibility, light weight even for a large size. Specifically, since the first substrate 100 has high thermal radiation, efficiency and lifetime of the organic electroluminescent diode are improved.

[86]

[87] FIG. 13 is a cross-sectional view showing an alternating current (AC) type plasma display panel device using a substrate according to the present invention. The AC type plasma display panel device has been widely used because of its advantage in panel size. In the AC type plasma display panel device, light is emitted by hit of an ultraviolet ray onto a fluorescent layer in vacuum. The substrate according to the present invention is used as a first lower substrate 200 in the AC type plasma display panel device.

[88] Most of the first lower substrate 200 is formed of an anodized material and a partition 174 is formed on one surface of the first lower substrate 200. The partition 174 is integrated onto the first lower substrate 200. A discharge space 176 having a stripe shape is defined by a groove between two adjacent partitions 174. An address electrode 172 having a stripe shape and corresponding to the discharge space 176 is formed in the first lower substrate 200, and a fluorescent layer 178 is formed in the discharge space 176.

[89] As compared with a first substrate 2 (of FIG. 3) of the related art, an additional first insulating layer 44 (of FIG. 3) and an additional partition 46 (of FIG. 3) are omitted in the first lower substrate 200 according to the present invention. Instead, the first lower substrate 200 itself functions as the first insulating layer and the partition, and the address electrode 172 is formed inside the first lower substrate 200. The first lower substrate 200 according to the present invention has the same operation and function as the first substrate 2 (of FIG. 3) according to the related art.

[90] Although not shown in FIG. 13, a second substrate faces and is spaced apart from the first lower substrate 200. An X electrode and a Y electrode are formed on an inner surface of the second substrate. The X and Y electrodes are alternately disposed along a direction crossing the discharge space 176. A second insulating layer and a protection layer are formed on the X and Y electrodes. As a result, a discharge cell is defined in the discharge space 176 by crossing of the address electrode 172 and the X and Y electrodes. The discharge cell is filled with an inert gas and a plasma is generated in the discharge cell by applying voltages to the address electrode and the X and Y electrodes. Ultraviolet light generated from the plasma is converted into visible light by the fluorescent layer 178 and the visible light is emitted to display images.

[91] FIGs. 14 to 18 are cross-sectional views showing a method of fabricating a first lower substrate 200 according to the present invention.

[92] As shown in FIG. 14, a metal thin plate 102a is prepared.

[93] As shown in FIG. 15, a photoresist is coated on both surfaces of the thin plate 102a.

The photoresist on one surface of the thin plate 102a is exposed using a mask and developed to form first and second photoresist patterns 132 and 134 on both surfaces of the thin plate 102a. The first photoresist pattern 132 has a specific shape, while the second photoresist pattern is formed on the entire surface of the thin plate 102a. The first photoresist pattern 132 is used for the discharge space 176 in a subsequent process and has a stripe shape corresponding to the partition 174.

[94] As shown in FIG. 16, a portion of the thin plate 102a exposed through the first photoresist pattern 132 is etched to form the partition 174 and the discharge space 176.

[95] As shown in FIG. 17, after the first and second photoresist patterns 132 and 134 are removed, a photoresist is coated on the other surface of the first lower substrate 200. The photoresist is exposed using a mask and developed to form a third photoresist pattern 136. The third photoresist pattern 136 may be formed by exposing and developing the second photoresist pattern 134 instead of removing the second photoresist pattern 134. The third photoresist pattern 136 is used for the address electrode 172 in a subsequent process. For example, the third photoresist pattern 136 may have a stripe shape or a slit shape corresponding to the address electrode 172.

[96] Sequentially, the thin plate 102a is immersed in an anodizing solution for electrolytic oxidation. Specifically, most of the thin plate 102a is converted into the anodized layer due to high electrolytic oxidation. It may be expected that a base material remains in a portion blocked by the third photoresist pattern 136. However, since the electrolytic oxidation occurs isotropically and even in the discharge space, the address electrode 172 is formed in the thin plate 102a corresponding to the portion blocked by the third photoresist pattern 136. When a metal pattern that is not oxidized is exposed through the other surface of the first lower substrate 200, a second electrolytic oxidation may be performed after the third photoresist pattern 136 is removed. As a result, the address electrode 172 inside the thin plate 102a is completed.

[97] As shown in FIG. 18, the first lower substrate 200 having the address electrode 172 therein is obtained and the fluorescent layer 178 is formed in the discharge space 176 to complete the first lower substrate 200 for a plasma display panel device of FIG. 13.

[98]

[99] FIG. 19 is a cross-sectional view showing an organic electroluminescent display device using a substrate according to the present invention. The substrate according to the present invention is used as a second lower substrate 300 in the organic electrolu- minescent display device.

[100] As shown in FIG. 19, most of the second lower substrate 300 is not formed of an anodized layer 304. Instead, a metal pattern 302 corresponding to an electric element such as a thin film transistor T is exposed to exterior. The metal pattern 302 includes at least one of aluminum and magnesium and functions as a metal line.

[101] The second lower substrate 300 may be fabricated through an electrolytic oxidation after forming corresponding photoresist patterns on both surfaces of the second lower substrate 300. Although not shown in FIG. 19, the method of fabricating the second substrate 300 may be referred to FIGs. 14 to 18. In addition, a driving circuit can be integrated in the second lower substrate 300 using the metal line and the integration of the driving circuit may be applied to a reflective liquid crystal display device and a plasma display panel device.

[102]

Industrial Applicability

[103] The present invention provides a substrate for a flat panel display device solving problems such as increase in weight and cost according to increase in size and having superiority to a glass or quartz substrate due to high thermal radiation.

[104] Specifically, the substrate according to the present invention may be applied to an emissive type flat panel display device such as a plasma display panel and an electroluminescent display device or a non-emissive type flat panel display device such as a reflective liquid crystal display device. In addition, since the substrate according to the present invention can be fabricated through a roll-to-roll process, the substrate has an advantage in mass production.

[105] Further, since the present invention provides a substrate having high flexibility, high flatness, high heat resistance and high insulation property, a flat panel display device using the substrate has improved quality.

[106] Moreover, since a substrate according to the present invention has a higher flexibility as compared to a glass or quartz substrate, the substrate according to the present invention has advantages in application to a flexible flat panel display device. Specifically, the substrate according to the present invention has high thermal radiation and low weight as compared with a stainless substrate.

[107] In addition, since a substrate according to the present invention may be applied to a solar cell or a radio frequency identification (RFID) because the substrate is adequate to an electric element having a large size and a high flexibility.

[108]

Claims

[1] A substrate for a flat panel display device, comprising an anodized layer, wherein the substrate includes a metal having at least one of aluminum and magnesium.

[2] The substrate according to claim 1, wherein the metal is selected from one of aluminum, aluminum alloy, magnesium, magnesium alloy and aluminum magnesium alloy.

[3] The substrate according to claim 1, wherein the anodized layer includes a plurality of pores, and the plurality of pores are sealed with an insulating material including resin or glass group.

[4] A method of fabricating a substrate for a flat panel display device, comprising: a) providing a metal thin plate including at least one of aluminum and magnesium; and b) forming an anodized layer on the metal thin plate.

[5] The method according to claim 4, further comprising: a') coating a photoresist on the metal thin plate after the step of a) before the step of b); and b') removing the photoresist after the step of b).

[6] The method according to claim 4, after the step of b), further comprising: c) sealing a plurality of pores in the anodized layer with an insulating material; and d) polishing the anodized layer to be flat.

[7] The method according to claim 4, wherein the step of b) includes electrolytically oxidizing the metal thin plate.

[8] The method according to one of claims 4 to 7, wherein each of the steps is performed through a roll-to-roll process where the metal thin plate winding around a first roll is transferred to be the substrate winding around a second roll.

[9] A flat panel display device, comprising: a substrate including an anodized layer, wherein the substrate includes a metal having at least one of aluminum and magnesium and a plurality of pixel regions are defined on the substrate; a switching element in each pixel region; and an organic electroluminescent diode in each pixel region, the organic electroluminescent diode connected to the switching element by one-to-one correspondence.

[10] A flat panel display device, comprising: a substrate including an anodized layer, wherein the substrate includes a metal having at least one of aluminum and magnesium and a plurality of pixel regions are defined on the substrate; a switching element in each pixel region; and a liquid crystal capacitor in each pixel region, the liquid crystal capacitor connected to the switching element by one-to-one correspondence. [11] The device according to one of claims 9 and 10, wherein the substrate includes a metal line pattern connected to the switching element, wherein the metal line pattern is exposed to an exterior and includes the at least one of aluminum and magnesium, and wherein the anodized layer wraps the metal line pattern. [12] A flat panel display device, comprising: a substrate including an anodized layer, wherein the substrate includes a metal having at least one of aluminum and magnesium and a discharge space is defined on a surface of the substrate by a groove in the anodized layer having a stripe shape; an address electrode in the anodized layer, the address electrode having a stripe shape and corresponding to the discharge space; a fluorescent layer in the discharge space; and an inert gas filling the discharge space. [13] A method of fabricating a flat panel display device, comprising: a) providing a metal thin plate including at least one of aluminum and magnesium; b) forming a first photoresist pattern on one surface of the metal thin plate; c) etching the one surface of the metal thin plate to form a discharge space that is defined by a groove between partitions having a stripe shape; d) forming a second photoresist pattern on the other surface of the metal thin plate; e) forming an anodized layer on the metal thin plate and an address electrode in the anodized layer, the address electrode having a stripe shape and corresponding to the discharge space; f) forming a fluorescent layer in the discharge space; and g) filling the discharge space with an inert gas.