KR20100021898A - Flexible light emission device and display device, and fabrication method the devices - Google Patents

Abstract

PURPOSE: A flexible electron light emission element and a display applying the same which enable fixation at installation place in a specific form using a flexible material are provided. CONSTITUTION: An electron emission material layer is formed on the surface of cathode. A flexible back face plate supports the cathode. An adhesive layer is provided between cathode and back face plate and is able to fix the cathode on the back face plate. A flexible front face plate(5) supports anode. A flexible spacer(3) of plate type is placed between rear face plate and front face plate. A fluorescent layer(6) is formed on the anode corresponding to a electron emission material layer.

Description

Flexible electroluminescent device and display using same and manufacturing method thereof {Flexible light emission device and display device, and fabrication method the devices}

The present invention relates to a flexible electroluminescent device, a flexible display using the same, and a method of manufacturing the same, a flexible electroluminescent device using an electron emitting material by acicular electron emitting materials such as CNTs, and a flexible display using the same It relates to a manufacturing method.

Electronic paper, called e-paper, has a structure that can be folded or rolled like paper, so that all structures are formed of a flexible material. The electronic paper may have a non-light emitting structure and a light emitting structure, and the non-light emitting structure may be in the form of using a dielectrophoretic particle as a reflection type. The light emitting structure has a form in which an organic light emitting material or CNT (carbon nano tube) is used. The light emitting structure using CNTs includes an anode having a CNT, which is an electron emission source, provided on the cathode and having a phosphor layer emitting light by electrons therefrom.

As the cathode material of the light emitting structure, CNT (carbon nanotube) or nano particles are preferred as the electron emission material. Carbon nanotubes (CNTs) are microstructures that are grown or composited in the form of tubes and are known in various forms. Such CNTs have very excellent electrical, mechanical, chemical, and thermal properties, and have been applied to various fields due to these advantages. CNTs have a low work function and a high aspect ratio and have a very large field enhancement factor because their top or emission ends have a small radius of curvature. Therefore, electrons can be emitted even under a low potential electric field.

Conventional methods for fabricating a flexible CNT field electron emission source include a method of growing CNT directly on a flexible substrate of various materials and a method of attaching powdered CNTs made of various synthetic methods to the flexible substrate.

CNT is grown directly on the flexible substrate to produce a flexible CNT field emission source. A conductive thin film such as chromium (Cr) or titanium (Ti) is deposited thinly on a Teflon sheet and several nanometers (nm) thereon. ) By forming a catalyst layer of iron (Fe), nickel (Ni), cobalt (Co), etc., and then growing CNT on the flexible Teflon sheet through the decomposition of hydrocarbon gas by irradiating several hundred watts of microwaves. Microwave irradiation method (AM14 (2002) 676, JACS127 (2005) 8234), polycarbonate, flexible polyimide foil coated with chromium (Cr) or titanium (Ti) to fabricate CNT field electron emitter After patterning and depositing a catalyst layer such as iron (Fe), nickel (Ni), and cobalt (Co) on the substrate, plasma dc grow discharge is generated to produce CNT on the flexible polyamide sheet at low temperature. Plasma enhanced chemical vapor deposition method (APL83 (2003) 4661), a vertically aligned, flexible CNT field electron emitter, to produce Ar + ion beams on a carbon-coated flexible polyimide substrate The ion beam sputtering method (Ion beam method, APL88 (2006) 103105, APL90 (2007) 143103) for sputtering and vertically synthesizing CNT on a flexible substrate surface at room temperature to produce a flexible CNT field electron emission source.

A method of manufacturing a flexible CNT field electron emission source by attaching the synthesized CNT powder to a flexible substrate, coating chromium (Cr) or titanium (Ti), etc. on an organic polymer substrate such as polycarbonate and PET to form an electrode. After patterning and depositing hundreds of micrometers (um) of gold (Au) and silver (Ag), and attaching a reactor such as a carboxyl group to the CNT, bonded to the surface of the patterned gold (Au), flexible CNT field electrons at room temperature Self assembly method (APL82 (2003) 3770) for fabricating sources, flexible polyimide foil coated with chromium (Cr) or titanium (Ti) as a cathode and stainless steel as an anode The plate is placed in a CNT suspension, and the electrophoresis is performed to produce a flexible CNT field emission source by depositing a positively charged CNT on a negative-voltage applied cathode substrate by applying an electric field to the two electrode substrates. Method (Electrophoresis method, ASS251 (2005) 258), homogeneously spraying CNT suspensions onto micropolymer thickness on organic polymer substrates such as PET and then irradiating several hundred watts of 2.45 GHz microwaves to sprayed CNTs and flexible polymers Microwave welding method (APL90 (2007) 103111), which produces a flexible CNT field electron emitter by making strong bonds between substrates in a short time, and made the surface-treated CNT into an aqueous solution ink, Dip coating method (APL90 (2007) 013120, APL90 (2007) 173124) to dip a CNT thin film on the surface of the polymer substrate to produce a flexible CNT field electron emission source.

Microwave irradiation, plasma chemical vapor deposition, and ion beam sputtering, which allow vertical growth of CNTs at low temperatures and atmospheric pressures, do not damage or bend the sensitive flexible substrates and provide structural control such as diameter, length, and density of CNTs on the flexible substrates. However, when depositing a catalyst metal on a large-area flexible substrate, it is difficult to secure the overall homogeneity and control the size of the catalyst metal particles, and the process procedure is difficult. There is a disadvantage.

Self-assembly, electrophoresis, microwave welding, and dip coating are available for selective deposition on flexible substrates at room temperature and are easy to large area, but are difficult to control thickness and density, poor homogeneity and reproducibility, and poor adhesion to flexible substrates. Reliability and stability issues arise with electron emission.

Exemplary embodiments of the present invention relate to flexible electroluminescent devices, flexible electroluminescent displays, and methods of making them that are easy to manufacture and reliable.

A flexible electroluminescent device according to an exemplary embodiment is:

Conductive plate-shaped cathodes;

A needle-shaped electron emission material layer formed on the surface of the cathode;

A flexible back plate supporting the cathode; And

An adhesive layer provided between the cathode and the back plate to fix the cathode to the back plate;

An anode facing the cathode;

A flexible front plate supporting the anode;

A plate-shaped flexible spacer provided between the back plate and the front plate; And

And a fluorescent layer formed on the anode to correspond to the electron emission material layer.

According to another embodiment, the electron emission material layer may be fixed by an adhesive layer to the cathode surface.

According to another embodiment, the spacer may include a hole corresponding to the electron emission material layer and the fluorescent layer.

According to another embodiment, the cathode may be a conductive double-sided tape having an adhesive layer formed on both sides thereof.

According to another embodiment, the fluorescent layer may include a flexible film and a fluorescent material layer deposited on one surface of the film.

A flexible electroluminescent display device according to an example embodiment is:

Flexible backplate;

A cathode on an upper surface of the back plate;

A flexible front plate opposite the back plate;

An anode formed on an inner surface of the front plate facing the back plate;

A plate-shaped flexible spacer provided between the front plate and the back plate and having a hole corresponding to an intersection of the cathode and the anode;

A needle-like electron-emitting material layer formed on the cathode corresponding to the hole;

An adhesive layer fixing the electron-emitting material layer to the cathode;

A phosphor layer formed on an anode corresponding to the hole; And

And a gate positioned between the cathode and the phosphor layer to extract electrons from the electron emission material layer between the front plate and the back plate.

In a display device according to another exemplary embodiment, the cathode is fixed by an adhesive layer provided below the cathode with respect to the substrate.

According to another embodiment, the electron emitting material layer may be fixed by an adhesive layer with respect to the cathode surface.

According to another embodiment, the spacer may include holes corresponding to the electron emission material layer and the fluorescent layer.

According to another embodiment, the cathode may be a conductive double-sided tape having an adhesive layer formed on both sides thereof.

According to another embodiment, the fluorescent layer may include a flexible film and a fluorescent material layer deposited on one surface of the film.

According to another embodiment, the spacer has a laminated structure by a plurality of plate-shaped unit spacers, the grid is located between the unit spacers.

Method for manufacturing a flexible electroluminescent device according to an exemplary embodiment of the present invention,

Forming a needle-like electron-emitting material layer on the plate-like template;

Transferring the electron-emitting material layer of the template to a plate-shaped cathode having an adhesive layer formed thereon;

Securing the cathode to the flexible backplate;

A surface treatment step of elevating the acicular electron emission material of the electron emission material layer on the cathode;

Preparing an anode and a front plate on which an fluorescent layer on the anode is formed on an inner surface thereof as opposed to the rear plate; And

And coupling the flexible plate-shaped spacers into one between the front plate and the back plate in an interposed state.

According to a method of manufacturing a flexible electroluminescent device according to another exemplary embodiment of the present invention,

The plate-like template is a filtration template having a plurality of cavities, and the formation of the electron-emitting material film includes the step of applying and drying a suspension in which the electron-emitting material is dispersed.

In addition, the surface treatment step is pressed by a member having an adhesive force with the electron-emitting material (erecting member) to separate it so that the electron-emitting material is perpendicular to the cathode, according to a specific embodiment, the member Adhesive tape or roller.

According to another specific and exemplary embodiment of the invention, the suspension comprises a solvent and a surfactant in which the CNTs are dispersed.

According to an exemplary embodiment, a flexible front plate and a flexible back plate, and a flexible plate-shaped spacer, a gate, and a gate insulating layer sequentially provided therebetween are combined into one and each of the flexible back plate and the front plate facing each other. A method of manufacturing an electroluminescent display in which a band-shaped cathode and an anode is formed on the inner surface, a needle-like electron emission material layer is formed on the cathode, and a fluorescent layer is formed on the anode,

Forming a plurality of electron-emitting material layers in the template at regular intervals;

Transferring the electron-emitting material layer to a cathode on which an adhesive layer is formed;

A surface treatment step of raising the electron-emitting material to the cathode by surface-treating the layer of the electron-emitting material on the cathode;

Fixing the cathode to the back plate;

Preparing a front plate having the anode and the fluorescent layer;

Preparing the spacer having a hole providing an electron beam moving space between the cathode and the anode; And

And combining the front plate and the back plate and spacers, gates, and gate insulation layers therebetween.

In the electroluminescent device and the display device according to the exemplary embodiment, since all materials are formed of a flexible material, the electroluminescent device and the display device can be folded or rolled up like paper, and can be fixed in a form that is appropriately modified in the form of an installation place. In addition, various kinds of needle-like electron-emitting materials, that is, tube- or rod-shaped electron-emitting materials having a predetermined length, for example, CNT powders are prepared using suspension filtering to prepare a well-dispersed CNT colloidal suspension. The suspension is fed onto an excitation filtration template which is then filtered and dried to form a CNT layer of density optimized for field electron emission. The CNTs dispersed in the suspension are very uniformly distributed, so that the CNT layer formed on the template also has a uniform distribution of CNTs. The CNT layer is transferred to the cathode on which the adhesive layer is formed to form a CNT layer stably fixed to the cathode. Subsequent surface treatment of the CNT layer raises and vertically aligns the CNTs with respect to the cathode, thereby dramatically increasing the number of CNTs contributing to electron emission. This exemplary embodiment enables the formation of a CNT layer for the cathode in a state of low temperature or room temperature, not high temperature, and thus does not have the problems experienced by conventional high temperature treatment. Therefore, the electron emission source according to the present invention is structurally very stable and is possible to emit electrons of high and even distribution.

The present invention can be easily manufactured at room temperature without complicated processes without using conductive organic / inorganic materials, binders and polymer pastes that adversely affect the field electron emission characteristics, thereby facilitating large area. In particular, since it is easy to obtain a large electron emission area, it is possible to have one CNT layer in one pixel, for example, in a display device.

In addition, since the CNT layer is formed using the suspension, the density of the CNT layer can be easily adjusted by controlling the CNT concentration in the suspension, and thus, the desired field emission density can be realized.

Hereinafter, a flexible electroluminescent device, a flexible electroluminescent display, and a method of manufacturing the same according to exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

The present invention utilizes a needle-shaped electron emission material. Needle-shaped electron-emitting materials include hollow nanotubes, hand-filled nanorods, and the representative material is carbon, and may be made of a metal material. In the following description of the embodiment will be described based on the carbon nanotube (CNT) which is a representative material of the acicular electron emission material. However, any material capable of emitting electrons as a needle may be applied, and thus the present invention is not limited to a specific example of the needle-like electron emission material.

FIG. 1A is a schematic exploded perspective view of a flexible electroluminescent device according to an exemplary embodiment, and FIG. 1B is an excerpt of the anode 4, the spacer 3, and the cathode 2 of the device shown in FIG. 1A. It is an exploded perspective view which shows the state when it rolled in the semicylindrical shape, and FIG. 2 is a schematic sectional drawing in the combined state.

1A, 1B and 2, the electroluminescent device 10 has a plate-shaped spacer 3 having a flexible back plate 1, a transparent flexible front plate 5, and a through hole 3a therebetween. It includes.

Between the flexible back plate 1 and the flexible spacer 3, a flexible cathode 2 having a conductive layer 2b and adhesive layers 2a and 2c on both sides thereof is located, and the spacer 3 and the front plate are located. Between (5), the flexible transparent anode 4 is located. The through hole 3a of the spacer 3 is a vacuum space through which an electron beam travels. Above and below the through hole 3a, a flexible fluorescent layer 6 which is excited by electrons and emits light and a needle-like electron-emitting material layer 7 (hereafter referred to as a CNT layer) are emitted. The fluorescent layer 6 is formed on the surface of the anode 4, and the CNT layer 7 is formed on the upper adhesive layer 2c of the cathode 2.

Substances to be used for the above elements include the following substances.

Backplate Material:

The back plate may be formed of a metal foil, a plastic film, or thin glass as a flexible plate of 0.1 mm or less.

As the metal foil, all kinds of metal foils having heat resistance that can withstand high process temperatures while securing impact resistance and flexibility at the same time, such as stainless steel foil and Ni metal film, may be used.

As the plastic film, a thermoplastic semi-crystalline polymer plastic substrate such as polyethylene terephthalate (PET) or polyethylenenaphthalate (PET), or a thermoplastic amorphous polymer plastic substrate such as polycarbonate (PC), polyethersulfone (PES), polymide (PI), or poly (late) Can be. In addition, by coating barrier layers on the above-mentioned plastic substrate, the plastic film can be selected and used according to the application to realize a flexible field emission source.

As the thin glass, for example, as described in Schott, ultrathin glass having a thickness of about 50 μm may be used, which has a thin coating of a polymer on the thin glass to maintain flexibility of the glass.

Front panel material:

As the transparent substrate material of 0.1 mm or less, the transparent plastic film and the transparent thin film glass mentioned above as the material of the back plate can be used.

Spacer Material :

Since the spacer exists only for the gap between the anode and the cathode, the conductor must be formed of an insulating material, the material of which may be a plastic substrate or thin film glass, referred to as the backplate material above.

Fluorescent layer :

General organic phosphors, fluorescent sheets (EJ-440, Apace Science) and the like can be used.

Anode :

Sputtering ITO, TCO, ZnO, IZO, CNT-conductive polymer composites, conductive polymer films, and various metals (Ni, Ti, Fe, Au, Pd, Ag, Cr, etc.) on transparent flexible substrates mentioned above as faceplate materials A plate material deposited at a thickness of several tens of micrometers to nanometers by sputtering or thermal evaporation may be used.

On the other hand, the cathode (2) will be described later in detail to be made of a conductive material in the form of a plate or ribbon produced separately from the back plate (1). As shown in FIG. 3, the cathode 2 may have a structure in which adhesive layers 2a and 2c are formed on both surfaces of the conductive layer 2b, and the lower end of each CNT of the CNT layer 7 is attached to the adhesive layer 2c. Strongly adhered to). Here, the cathode 2 is substantially made of the conductive layer 2b and the upper and lower adhesive layers 2a and 2c have been described as an additional element of the cathode 2 for convenience and not as part of the cathode. Thus, "cathode" as referred to in the description of the following embodiments means the conductive layer 2b itself, and may be understood to include adhesive layers 2a and 2c on both sides thereof in some cases. 2a, 2c) may be understood as a separate element from the cathode. On the other hand, the CNT is substantially made of pure CNT, and is easy to manufacture because it is fixed to the back plate 1 in a state where the CNT layer 7 is formed on the cathode (2). In particular, such a structure does not require a high temperature process, and thus the economic burden of the high temperature process is not disadvantageous. In particular, since the adhesive layer, which may include an organic substance, is not mixed with CNTs and is provided only at the lower portion thereof, the possibility of colliding with electrons is very low, and thus generation of organic gas due to electron collision or the like does not occur.

For example, as illustrated in FIG. 4, the CNT layer 7 may have various shapes such as polygons, ellipses, stars, alphabets, Korean characters, and numbers, such as rectangles, rhombuses, triangles, and pentagons. Therefore, the form of light emission can be diversified. The shape of the through hole 3a of the spacer 3 may also be varied to correspond to various shapes of the electron-emitting material layer.

Meanwhile, the fluorescent layer 6 may be formed of a general flexible fluorescent material. According to another embodiment, a phosphor sheet having a transparent flexible film and a phosphor layer coated on the film surface may be applied to the phosphor layer 6. As a commercial item, EJ-440 of APACE Sience, Inc. can be used as the fluorescent layer 6, for example.

The electroluminescent element of such a structure is suitable for a simple on-off type lamp and the like since it is a simple two-pole type. Such lamps can be used in various forms such as traffic signs, traffic lights, billboards, and the like. In terms of the size, the size of the light emitting area can be selected within a very wide range, ranging from several μm ² to several hundreds m ² , depending on the specification of the application object required. In such electroluminescent devices, i.e. lamps, a grid is formed which controls the emission of electrons from the electron-emitting material layer 7 of the cathode by forming an electric field between the cathode 2 and the anode 4. Do.

FIG. 5 shows a bent state of the electroluminescent device manufactured according to the embodiment, and FIG. 6 is a photograph showing that the electroluminescent device shown in FIG. 5 successfully emits light.

Hereinafter, a method of manufacturing an electroluminescent device according to an exemplary embodiment will be described.

First, a CNT colloidal suspension (hereinafter referred to as a suspension) and a filter paper (filtration template) made of materials such as Teflon, ceramic, Aanodic Aluminum oxide (AOA), and polycarbonate are prepared as templates. A suspension is a colloidal liquid made by dispersing powdered CNTs in a solvent and a surfactant. It is desirable to sonicate for more even dispersion. The filter paper filters the suspension, leaving only CNTs on its surface, to dry the CNT suspension and to retain only the CNTs in a predetermined pattern for transfer to the plate cathode. CNTs include single-walled carbon nanotubes (SWCNTs), double-walled carbon nanotubes (DWCNTs), thin multi-walled carbon nanotubes (MWCNTs), and thick MWCNTs. The solvent is any one of ethanol, dimethyl formamide, tetrahydrofuran, dimethyl acetamide, 1,2 dichloroethane and 1,2 dichlorobenzene.

And the surfactant is sodium dodecylbenzene sulfonate (NaDDBS C1 ₂ H ₂₅ C ₆ H ₄ SO ₃ Na), sodium butylbenzene sulfonate (NaBBS C ₄ H ₉ C ₆ H ₄ SO ₃ Na), sodium benzoate (C ₆ H ₅ CO ₂ Na), sodium dodecyl sulfate (SDS; CH ₃ (CH ₂ ) ₁₁ OSO ₃ Na), Triton X-100 (TX100; C ₈ H ₁₇ C ₆ H ₄ (OCH ₂ CH ₂ ) n-OH; n 10), dodecyltrimethylammonium bromide (DTAB; CH ₃ (CH ₂ ) ₁₁ N (CH ₃ ) ₃ Br) or Arabic gum.

As shown in Fig. 7A, the suspension is applied in a predetermined pattern to a filtration template 21 made of filter or the like and then dried to form a CNT film 7 '. The application area of the suspension solution corresponds to the shape of the cathode of the electron emission source, for example, the shape of the protrusions of various shapes shown in FIG. 4, and various changes are possible depending on the type of cathode required for the application. Here, by controlling the ratio or concentration of the solvent, the surfactant, and the CNT in the suspension, the CNT density can be freely controlled and the optimum electron emission density can be realized according to the ambient electrical conditions, and the optimum conditions can be repeatedly reproduced and homogenized. Density CNT films can be formed. A suspension is formed in the filtration template 21, with only CNT remaining and the liquid material passing through the filtration template. When the drying process is performed in this state, the CNT film 7 'is formed on the surface of the template 21. This process may include a natural drying or vacuum drying process at room temperature or high temperature.

As shown in FIG. 7B, a double-sided tape type cathode 2 having adhesive layers 2a and 2c formed on both surfaces of the conductive layer 2b is prepared. During the actual process, the lower adhesive layer 2a will be protected by a release paper which prevents the adhesion of foreign matter, which is not shown in the drawings. The cathode 2 is formed of any one of a conductive sheet, a conductive fabric, or a conductive substrate, and thus the conductive layer 2b is formed of such a material.

The adhesive layers 2a and 2c may have conductivity, and may be formed of a material in which conductive particles, for example, modified nickel, and various modified metal groups and polymer resins are mixed. Specifically, the conductive layer 2b is an aluminum foil or a conductive substrate (thickness: 0.01 to 0.04 mm), a conductive sheet made of various metal groups such as copper or nickel, and a thickness of 0.01 to 0.04 mm) and a conductive fabric (thickness: 0.01 to 0.20 mm).

The adhesive layers 2a and 2c are mixtures of conductive powders such as nickel and carbon pigments and adhesive resins such as acrylic ester polyol copolymers, and preferably have a total contact resistance of less than 0.1 Ω / 25 mm ² . to be. Such an adhesive layer is preferably formed of a heat resistant material that can be used even at high temperatures.

As shown in FIG. 7C, the CNT film 7 ′ on the template 21 is brought into contact with the adhesive layer 2c on one side of the cathode 2 (upper in the drawing) at a predetermined pressure, and then separated therefrom, thereby providing a template 21. CNT film 7 'is formed on the cathode 2 side.

The process of FIG. 7d shows a method of surface treatment of a CNT layer in which the CNTs of the CNT layer 7 which are randomly arranged in the cathode 2 are vertically aligned. The sticky tape 22 is adhered to the CNT layer 7 'on the cathode 2, as shown in FIG. 7D (a), and then lifted off. In this way, the CNT exposed on the surface in the CNT layer 7 is aligned in the direction perpendicular to the cathode 2 by the stickiness of the tape 22. That is, CNT is raised against the cathode 2 using the tape 22. In addition to the method of using such a tape 22, as shown in (b) of FIG. 7D, the CNT is cathode by rolling the surface of the CNT layer 7 to a predetermined pressure by using a roller 23 having adhesiveness to the surface. It can be raised up and aligned in the vertical direction. In this vertical alignment process, the CNTs weakly fixed to the adhesive layer 2c on the surface of the cathode 2 will be separated therefrom and removed. However, most of the CNTs have their lower ends fixed to the cathodes 2 by strong adhesive force, and thus the upper ends thereof. The parts will be aligned vertically in a upward lift.

FIG. 7E shows the coupling of the cathode 2 to the back plate 1. 7C to 7E, the cathode 2 and the adhesive layers 2a and 2c on both sides thereof are expressed very thickly, but this is exaggerated for clarity.

A flexible spacer 3 having a through hole 3a is mounted in advance as shown in FIG. 7F.

As shown in FIG. 7G, a front plate 5 having an anode 4 and a fluorescent layer 6 formed on its inner surface is mounted on the spacer 3 to obtain a desired electroluminescent device.

The manufacturing process of the electroluminescent device 10 described above is in accordance with an exemplary embodiment of the present invention can be modified in various forms. For example, the surface treatment of the CNT layer 7 for vertical alignment of the CNTs may be performed after the cathode 2 is fixed to the back plate 1. That is, after the process of FIG. 7E after the process of FIG. 7C, the surface treatment is finally performed by the adhesive tape 22 or the roller 23 as shown in FIGS. 7D and 7B. CNT vertical alignment process can be performed. However, the present invention is not limited to the vertical alignment method by the specific surface treatment of the CNT as described above, and may be carried out in various ways within the conventional technical scope.

As a feature of the present invention, the cathode is a separate plate-like conductor, the surface of which is fixed to the cathode base with the CNT film fixed by the adhesive layer, and the front plate, the back plate, the spacer, etc. are structurally formed of a flexible plate-like material, and In general, the point is formed by a flexible material. That is, in the related art, CNTs are grown or fixed while the cathode is already fixed to the substrate or the like, but the present invention is that the CNT film is formed on the plate-shaped cathode before being combined with the cathode base supporting the substrate or the cathode. In the above-described embodiment, the cathode base may correspond to a substrate of a general electron emission source. The electron emission source according to the present invention is characterized in that the CNT is fixed to the cathode by an adhesive layer thereunder, which is an electron emission source by an existing face, that is, an electron emission source in a form in which CNT and paste are mixed. Has other structural features.

FIG. 8A is a schematic plan view showing the electrode arrangement of an electroluminescent display that can be obtained from the modification of the exemplary embodiment described above, and FIG. 8B is a cross-sectional view taken along line AA ′ of FIG. 8A. 8A and 8B, that is, a flexible electroluminescent element or a flexible electroluminescent display capable of light emission control has a gate electrode or a grid electrode forming an electric field on an electron movement path.

First, referring to FIG. 8A, an X-Y matrix structure in which the cathode 2 and the anode 4 are arranged in parallel to each other in a direction perpendicular to each other is formed. Each intersection of the anode 5 and the cathode 2 is defined as a unit pixel region, in which the fluorescent layer 6 and the CNT layer 7 are located.

Referring to FIG. 8B, a gate insulating layer and a gate are added to the structure of the electroluminescent device shown in FIG. 7G or FIG. 2. That is, the cathode 2 having the above-described structure is positioned between the flexible back plate 1 and the spacer 3, and the gate 9 and the gate insulating layer () are disposed between the spacer 3 and the front plate 5. 8) and the transparent anode 4 are in order. Each through hole 3a, 9a, 8a of the spacer 3, the gate 9, and the gate insulating layer 8 forms a well which is a vacuum space through which an electron beam travels. Above and below the well by the through-holes is a fluorescent layer 6 which is excited and emitted by electrons and a CNT layer 7 which emits electrons. The fluorescent layer 6 is formed on the surface of the anode 4, and the CNT layer 7 is formed on the upper adhesive layer 2c of the cathode 2. In the above structure, the arrangement of the cathode 2, the anode 4 and the gate 9 therebetween is in accordance with the general passive matrix driving scheme.

9 is an SEM image showing the CNT layer after surface treatment. As shown in FIG. 9, when the surface treatment is vertically aligned, it can be confirmed by SEM observation that the CNTs lying horizontally are aligned in the vertical direction with a uniform length.

FIG. 10 shows CNT electron emission sources for measuring field emission in a flat condition of the electrode structures of the anode and cathode and field electron emission in a bending condition of the electrode structures of the anode and cathode. The current density (J (A / cm ² )) versus electric field (The applied electric field, F (V / μm)) is a graph of comparison data. The bending condition is applied to cylindrical structures with diameters of 20 mm (radius of curvature 10 mm) and 40 mm (curve radius of 20 mm) to vary the degree of bending in tensile and compressive modes. Electric field emission was measured. Field emission experiments were carried out on a two-electrode structure consisting of an anode, a thin, thin stainless steel sheet, and a cathode, a surface-treated CNT flexible field emission source. The distance between the two electrodes was 550 µm, and the electron emission area was 0.2826 cm. ² The vacuum level is 2 * 10 ^-7 torr and the applied voltage is from 0V to 3500V. The CNT powders used as CNT field electron emission sources are DWCNTs and MWCNTs with average diameters of 2.5 nm and 20 nm, respectively. The concentration of colloidal suspension of DWCNTs and MWCNTs was performed at 20 mg / l (DWCNTs, MWCNTs amount: 10 mg) optimized in this experiment. In the case of DWCNTs, the turn-on fields required to obtain a current density of 0.1 mA / cm ² at flat and unbending were 0.82 V / μm, respectively, and the fields required to obtain a critical current density of 1 mA / cm ² were 1.62 V / m, respectively. Μm. On the other hand, the turn-on electric field required to obtain a current density of 0.1 mA / cm ² in the bent state of tension mode and compression mode was 0.77-0.84 V / µm, and the electric field required to obtain a critical current density of 1 mA / cm ² was Each was 1.62-1.72 V / µm. In the case of MWCNTs, the turn-on fields required to obtain a current density of 0.1 mA / cm ² at flat and unbending were 1.26 V / μm, respectively, and the fields required to obtain a critical current density of 1 mA / cm ² were 2.33 V / m, respectively. Μm. On the other hand, the turn-on electric field required to obtain a current density of 0.1 mA / cm ² in the bent state of tension mode and compression mode was 1.22-1.37 V / µm, and the electric field required to obtain a critical current density of 1 mA / cm ² was Respectively 2.33-2.54 V / μm. That is, in the case of the flexible CNT field electron emission source according to the present invention, it can be seen that there is no significant difference in the field electron emission characteristics in the flat state and the bent state.

Figure 11 shows the results of testing the electron emission stability of each type of CNT in a bent state (curvature radius 20 mm), it can be seen that MWCNTs are more stable than DWCNTs.

It is possible to apply to a display device by applying such a single electron emission source. Display devices typically have pixels that can be electrically addressed in an XY matrix state, with cathodes arranged in a number of parallel stripes, so that each cathode has a length covering either direction of the screen and each pixel on its surface. Will have a corresponding CNT layer.

As described above, according to various embodiments of the present invention, the CNT thin film formed using the suspension filtering method can be easily transferred using a conductive tape having a strong adhesive strength, and the adhesive strength between the CNT thin film and the conductive tape can be easily transferred. Since it is very excellent, it is possible to improve the field electron emission characteristics of the CNT thin film through a simple surface post-treatment process, and obtain a stable and reliable field electron emission characteristics without desorption of the CNT thin film during field electron emission even in a high electric field. In addition, by controlling the concentration of the uniformly dispersed CNT colloidal suspension, the active electron emission site density of the CNT thin film can be easily adjusted. It is possible to manufacture a large area CNT field electron emission source. In addition, all materials such as a front plate, a back plate, a spacer, and a gate insulating layer are made of a flexible material, so that a high quality flexible lamp and electronic paper that can be folded or rolled like a paper can be obtained.

This field of application of the present invention can be applied to any field that requires light emission. For example, it is possible to apply to a billboard, a traffic sign, a traffic light, etc. from a light emitting device for a small position confirmation. In addition, as a passive matrix driving method capable of light emission control, it can be applied as a flexible electroluminescent display as a kind of general electronic paper.

1A is an exploded perspective view illustrating a schematic structure of a flexible electroluminescent device according to an exemplary embodiment.

FIG. 1B is an exploded perspective view illustrating main components of the flexible electroluminescent device shown in FIG. 1A.

FIG. 2 is a schematic cross-sectional view of the flexible electroluminescent device shown in FIG. 1.

3 is a cross-sectional view illustrating a stacked structure of a cathode applied to an exemplary embodiment.

4 is a diagram illustrating various patterns of different cathodes in various embodiments.

5 shows a state in which the electroluminescent device manufactured according to the embodiment is bent.

6 is a photograph showing that the electroluminescent device shown in FIG. 5 is successfully emitting light.

7A to 7G show a manufacturing process of a flexible electroluminescent device according to an exemplary embodiment.

8A is a schematic plan view showing an electrode arrangement structure of a flexible electroluminescent display according to an exemplary embodiment.

FIG. 8B is a cross-sectional view taken along the line AA ′ of FIG. 8A.

9 is a high magnification SEM image of the surface-treated CNT layer.

10 shows the electric field emission measured in the flat condition of the electrode structures of the anode and the cathode, and the current of the CNT electron emission source in which the field electron emission was measured in the bending condition of the electrode structures of the anode and the cathode. The current density (J (A / cm 2)) vs. the applied electric field (F (V / μm)) comparison data.

Figure 11 shows the results of testing the electron emission stability of each type of CNT in the bent state.

Claims (30)

Conductive plate-shaped cathodes; A needle-shaped electron emission material layer formed on the surface of the cathode; A flexible back plate supporting the cathode; And An adhesive layer provided between the cathode and the back plate to fix the cathode to the back plate; An anode facing the cathode; A flexible front plate supporting the anode; A plate-shaped flexible spacer provided between the back plate and the front plate; And And a fluorescent layer formed on the anode to correspond to the electron emitting material layer. The method of claim 1, A flexible electroluminescent device, characterized in that an adhesive layer for fixing the electron-emitting material layer is formed on the upper surface of the cathode. The method of claim 1, The cathode is a flexible electroluminescent device, characterized in that it has a double-sided tape form the adhesive layer is formed on both sides. The method of claim 1, The spacer has a through hole corresponding to the fluorescent layer and the electroluminescent material layer. The method according to any one of claims 1 to 4, The electron-emitting material layer is a flexible electroluminescent device comprising at least one of single-walled (SW) CNTs, double walled (DW) CNTs, multi-walled (NTW) CNTs, nanowires. The method of claim 5, wherein The cathode is a flexible electroluminescent device, characterized in that formed of any one of a conductive sheet (Conductive Sheet), a conductive fabric (Conductive Fabric) or a conductive substrate (Conductive substrate). The method according to any one of claims 1 to 4, The cathode is a flexible electroluminescent device, characterized in that formed of any one of a conductive sheet (Conductive Sheet), a conductive fabric (conductive fabric), or a conductive substrate (Conductive substrate). The method according to any one of claims 1 to 4, The fluorescent layer is a flexible electroluminescent device, characterized in that the flexible sheet and the fluorescent sheet formed with a fluorescent material layer on one surface of the film. The method of claim 5, wherein The fluorescent layer is a flexible electroluminescent device, characterized in that the flexible sheet and the fluorescent sheet formed with a fluorescent material layer on one surface of the film. The method of claim 7, wherein The fluorescent layer is a flexible electroluminescent device, characterized in that the flexible sheet and the fluorescent sheet formed with a fluorescent material layer on one surface of the film. Flexible backplate; A cathode on an upper surface of the back plate; A flexible front plate opposite the back plate; An anode formed on an inner surface of the front plate facing the back plate; A plate-shaped flexible spacer provided between the front plate and the back plate and having a hole corresponding to an intersection of the cathode and the anode; A needle-like electron-emitting material layer formed on the cathode corresponding to the hole; An adhesive layer fixing the electron-emitting material layer to the cathode; A phosphor layer formed on an anode corresponding to the hole; And And a gate positioned between the cathode and the phosphor layer to extract electrons from the electron emission material layer between the front plate and the back plate. The method of claim 11, A flexible electroluminescent display, characterized in that an adhesive layer for fixing the electron-emitting material layer is formed on the upper surface of the cathode. The method of claim 11, The cathode has a flexible electroluminescent display, characterized in that it has a double-sided tape having an adhesive layer formed on both sides thereof. The method of claim 11, And the spacer and the gate insulating layer have through holes corresponding to the fluorescent layer and the electroluminescent material layer. The method according to any one of claims 11 to 14, The electron-emitting material layer includes at least one of single-walled (SW) CNTs, double walled (DW) CNTs, multi-walled (NTW) CNTs, and nanowires. The method of claim 15, And said cathode is formed of any one of a conductive sheet, a conductive fabric, or a conductive substrate. The method according to any one of claims 11 to 14, And said cathode is formed of any one of a conductive sheet, a conductive fabric, or a conductive substrate. The method according to any one of claims 11 to 14, The fluorescent layer is a flexible electroluminescent display, characterized in that the fluorescent sheet comprising a flexible film and a fluorescent material layer formed on one side of the film. The method of claim 15, The fluorescent layer is a flexible electroluminescent display, characterized in that the fluorescent sheet comprising a flexible film and a fluorescent material layer formed on one side of the film. The method of claim 7, wherein The fluorescent layer is a flexible electroluminescent display, characterized in that the flexible sheet and the fluorescent sheet formed with a fluorescent material layer on one side of the film. Forming a needle-like electron-emitting material layer on the plate-like template; Transferring the electron-emitting material layer of the template to a plate-shaped cathode having an adhesive layer formed thereon; A surface treatment step of elevating the acicular electron emission material of the electron emission material layer on the cathode; And Preparing an anode and a front plate on which an fluorescent layer on the anode is formed on an inner surface thereof as opposed to the rear plate; And combining the flexible plate-shaped spacers between the front plate and the rear plate in one state in an interpose state. And fixing the cathode to the flexible back plate between the transferring step and the surface treatment step, and between the surface treatment step and the step of preparing the front plate. Manufacturing method. The method of claim 21, The template is a manufacturing method of a flexible electroluminescent device, characterized in that the filter template having a filterability. The method of claim 21, Forming an electron-emitting material layer on the template includes: Supplying a suspension in which electron-emitting materials are dispersed on a template; Method for producing a flexible electroluminescent device comprising the step of drying the suspension. The method of claim 21, The surface treatment step is a flexible electroluminescent device, characterized in that using any one of a method using an adhesive tape, roller rubbing method, ion beam irradiation method, plasma treatment method, laser beam irradiation method, neutron beam irradiation method, hydrogen gas exposure method Way. The method according to any one of claims 21 to 24, The cathode is a method of manufacturing a flexible electroluminescent device, characterized in that formed of any one of a conductive sheet (Conductive Sheet), a conductive fabric (conductive fabric), or a conductive substrate (Conductive substrate). A flexible front plate, a flexible plate-shaped spacer, a gate, a gate insulating layer, and a flexible back plate are sequentially combined, and cathodes and anodes are formed on inner surfaces of the back plate and the front plate, respectively, and the needle-shaped electron-emitting material is formed on the cathode. In the method of manufacturing a flexible electroluminescent display wherein a layer is formed and a fluorescent layer is formed on the anode, Forming a plurality of electron-emitting material layers in the template at regular intervals; Transferring the electron-emitting material layer to a cathode on which an adhesive layer is formed; A surface treatment step of surface treating the electron-emitting material layer on the cathode to raise the electron-emitting material to the cathode; Preparing a front plate having the anode and the fluorescent layer; Preparing the spacer having a hole providing an electron beam moving space between the cathode and the anode; And Combining the front plate and the back plate and spacers, gates, and gate insulating layers therebetween into one; Fixing the cathode to the back plate between the transferring step and the surface treatment step, and between the surface treatment step and the step of preparing the front plate; flexible electroluminescence Method of manufacturing the display. The method of claim 26, The template is a manufacturing method of a flexible electroluminescent display, characterized in that the filter template having a filterability. The method of claim 26, Forming an electron-emitting material layer on the template includes: Supplying a suspension in which electron-emitting materials are dispersed on a template; Method for producing a flexible electroluminescent display comprising the step of drying the suspension. The method of claim 26, The surface treatment step may be performed using any one of a method using an adhesive tape, a roller rubbing method, an ion beam irradiation method, a plasma treatment method, a laser beam irradiation method, a neutron beam irradiation method, and a hydrogen gas exposure method. Way. The method according to any one of claims 26 to 29, The cathode is a method of manufacturing a flexible electroluminescent display, characterized in that formed of any one of a conductive sheet, a conductive fabric, or a conductive substrate.

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