KR100891619B1 - Method for manufacturing spacer for field emission device and field emission device accordingly - Google Patents

Abstract

The present invention relates to a method of manufacturing a spacer for a field emission display (FED) and a field emission device according to the present invention. In the method of manufacturing a spacer for a field emission device, first, an insulator powder is prepared, and the prepared insulator And mixing the conductive solution or paste containing the metal component with powder, followed by sintering the insulator and the metal component into a mixed phase. According to the present invention, the specific resistance of the spacer can be in the range of 10 ⁸ -10 ¹⁰ Ωm, thereby easily discharging the charges charged to the spacer to the outside, thereby preventing the distortion of the electric field due to the charging of the spacer. In addition, since the metal component is mixed with the insulator by using a conductive solution or paste, there is an effect of producing a mixed phase having high metallic dispersion.

Field emission, spacers, conductive solutions, conductive pastes

Description

Manufacturing method of spacer for field emission device and field emission device according to it {Manufacturing method of Spacer for Field Emission Display and FED using The Same}

The present invention relates to a field emission display (FED), and more particularly to a spacer of the FED and a method of manufacturing the same. More specifically, the present invention relates to a spacer material of the FED that can suppress generation of secondary electrons generated by charging of the spacer and prevent distortion of an electric field.

Field emission device (FED) has simple electrode structure, high speed operation with the same principle as CRT, full color, full gray scale, high brightness and high It has all the advantages that a display should have, such as video rate speed.

1 is a schematic cross-sectional view of a FED panel applied to a conventional micro-tip field emission display, and FIG. 2 is an enlarged cross-sectional view of part A of FIG. 1.

As shown here, the FED panel has an anode plate 1 and a cathode plate 2 spaced apart at regular intervals so that a vacuum gap 3 is formed. It is provided on the lower side, and a spacer 4 is provided so that the gap 3 can be maintained between the anode plate 1 and the cathode plate 2. In addition, the anode plate 1 has a black matrix 6, a phosphor 7, and an anode electrode 8 in order to increase contrast on the inner surface of the front plate 5. The ground electrode 9 is formed below the spacer 4.

The cathode plate 2 has a cathode electrode 12 formed on an upper surface of the substrate 11, and an emitter 13, which is an electron emission source, is formed on an upper surface of the cathode electrode 12. . In addition, a gate electrode 14 having a gate 14a for drawing electrons generated from the emitter 13 is formed above the cathode electrode 12, and the gate electrode 14 and the cathode are formed. The electrode 12 is insulated by a gate insulator 15. A focusing electrode 16 for focusing electrons is provided above the gate electrode 14, and the focusing electrode 16 and the gate electrode 14 are insulated by a focusing insulator 17.

In the field emission device having the above structure, when a sufficient voltage is applied to both ends of the gate electrode 14 and the cathode electrode 12, a strong electric field is formed thereby, and thus the emitter 13 is formed by the electric field. Electrons are emitted by quantum mechanical tunneling. The emitted electrons pass through the gate 14a of the gate electrode 14, and a field emitter array (FEA) is formed through matrix gates through the gate electrode 14 and the cathode electrode 12. The electrons are emitted during the time when the voltage is applied to the gate electrode 14.

The emitted and accelerated electrons collide and emit light with high energy at a pixel of the phosphor 7 located behind the upper anode electrode 8, and the matrix arrayed R (red) and G (green) A color display is implemented by phosphor dots of B (blue).

In order to fabricate a panel having high color purity and brightness in the field emission device as described above, electrons emitted from the emitter 13 must be accelerated and collided with the phosphor 7 corresponding thereto. If the electrons do not hit the phosphors 7 corresponding to the emitter 13 but hit the adjacent phosphors 7, light emission occurs in the adjacent phosphors 7, thereby degrading color purity. In addition, the corresponding phosphor 7 is reduced in brightness to appear dark. Therefore, the electron beam of the ideal field emission device must move vertically in the cathode plate 2 to excite only each corresponding phosphor 7.

The electron beam is essentially forced to move perpendicular to the equipotential plane. When voltage is applied between the cathode plate 2 and the anode plate 1 facing in parallel to each other, an equipotential surface parallel to the two plates is formed between the two plates, so the electron beam must move perpendicular to the cathode plate 2. . However, in actual field emission devices, there are elements that disturb the movement of the electron beam to generate the distortion of the beam.

Among the various factors, the distortion of the electron beam by the spacer 4 represents the most serious problem. In order to maintain the electric field in the field emission display device, the spacer 4 should basically be an insulator. Since the insulator has a secondary electron emission coefficient greater than 1, the charge is positive when the electron beam is hit by the adjacent emitter 13. Such charging of the spacer 4 distorts the electric field around the spacer 4, thereby causing distortion of the electron beam.

Therefore, in the related art, various methods for preventing such electric field distortions have been proposed. Representative methods include a method of depositing a material having a low secondary electron emission coefficient on the side of the spacer 4, a method of depositing a conductive thin film on the side of the spacer 4, and a metal electrode strip on the side of the spacer 4. Forming method; However, these methods are performed by adding a separate process after manufacturing the spacer 4, there is a problem to increase the manufacturing process and manufacturing cost.

Accordingly, the present invention has been made to solve the above problems, and after mixing a conductive solution or paste containing a metal component in the insulator powder, without a separate post-processing step to prevent electric field distortion, the insulator and the By sintering the metal components into a mixed phase, it is intended to prevent charges from accumulating on the spacers themselves. That is, the present invention is to manufacture a FED capable of preventing distortion of an electric field caused by charging of the spacer by easily discharging an electric charge charged to the spacer to the outside only by manufacturing a spacer having a specific resistance within a predetermined range. Is the purpose. In addition, the present invention not only prevents the distortion of the electric field due to the charging of the spacer, but also mixes the metal component with the insulator by using a conductive solution or paste that is already evenly sprayed to form a mixed phase with a significantly high dispersion of the metal component. It is for manufacturing.

According to an aspect of the present invention, a method for manufacturing a spacer for a field emission display (FED) according to the present invention includes preparing an insulator powder and preparing the prepared insulator powder. Mixing a conductive solution or paste containing a metal component and sintering the insulator and the metal component into a mixed phase.

Here, the conductive solution or paste containing the metal component is preferably a solvent containing metal particles including silver (Ag) or copper (Cu), and the metal particles are silver nano particles, metal particles such as copper, or It is more preferable that the metal compound, the metal particles are most preferably included in the range of 20% by weight to 50% by weight. In addition, the method for manufacturing a spacer for a field emission device according to the present invention may further include stacking a plurality of insulating or conductive green sheets according to conductivity provision characteristics.

Furthermore, another embodiment of the present invention may be a field emission device which is manufactured by the spacer manufacturing method as described above, and includes a spacer having a specific resistance value in the range of 10 ⁸ to 10 ¹⁰ Ωm.

Specific details of other embodiments are included in the detailed description and the drawings.

As described above, according to the present invention, after the conductive powder or particle-free conductive solution or paste containing a metal component is mixed with the insulator powder without a separate post-treatment process for preventing electric field distortion, the insulator and the metal component are mixed phases. By sintering to achieve this, it is possible to prevent charges from accumulating on the spacers themselves. That is, by simply manufacturing a spacer having a constant resistivity within the range of 10 ⁸ to 10 ¹⁰ Ωm, the FED capable of easily discharging the electric charges charged to the spacer to the outside, thereby preventing the distortion of the electric field caused by the charging of the spacer. There is an effect that can be provided. In addition, the present invention has the effect of producing a mixed phase with high metallic dispersibility because the metal component is mixed with the insulator by using a conductive solution or paste.

Advantages and features of the present invention and methods for achieving them will be apparent with reference to the embodiments described below in detail with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but will be implemented in various forms, and only the present embodiments are intended to complete the disclosure of the present invention, and the general knowledge in the art to which the present invention pertains. It is provided to fully convey the scope of the invention to those skilled in the art, and the present invention is defined only by the scope of the claims.

3 is a schematic cross-sectional view of a FED panel having a spacer according to a preferred embodiment of the present invention, Figure 4 is an enlarged cross-sectional view showing a cathode plate of the field emission display according to an example of the present invention.

First, as shown in FIG. 3, in the FED according to the present invention, an upper anode plate 101 and a lower cathode plate 102 are disposed at a predetermined interval, and the anode plate 101 and the cathode are disposed. Sealing material (not shown) is provided at the edge between the plates 102 to maintain the interior in a vacuum, and inside the anode plate 101 and the cathode plate 102 provided with the sealing material (not shown). The spacer 104 is provided so that the anode plate 101 and the cathode plate 102 can be maintained at a constant interval at all times. In addition, the anode plate 101 has a structure in which a phosphor 112 is formed on an inner surface of the windshield 111 having a predetermined area.

In addition, as shown in FIG. 4, the cathode plate 102 includes a first buffer layer 202 and a second buffer layer 203 formed on an upper surface of the rear glass 201, and an upper surface of the second buffer layer 203. A lower electrode 204 formed on the upper surface of the lower electrode 204, a tunnel insulating film 205 formed on the upper surface of the lower electrode 204, a field insulating film 206 formed outside the tunnel insulating film 205, and the tunnel insulating film ( The upper electrode 207 formed on the upper surface of the 205, the upper electrode bus 208 formed outside the upper electrode 207, and the overhang insulating film 209 formed on the upper electrode bus 208 in turn. And the field-emitting device 211 of the metal-insulator-metal (MIM) type formed of the top electrode 210, the tunnel insulating film 205 when an electric field is applied to the upper electrode 207 and the lower electrode 204. Electrons are emitted toward the upper phosphor 112.

In the present invention having the structure described above, the spacer 104 installed between the anode plate 101 and the cathode plate 102 mixes a conductive solution or paste containing a metal component in an insulator powder, The insulator and the metal component are manufactured by sintering to form a mixed phase.

In general, in order to maintain a constant electric field in the FED, the spacer should basically be made of an insulator. Thus, the spacer is usually made of an insulating material or a ceramic material. However, the spacer made of only an insulating material or a ceramic material as described above has a secondary electron emission coefficient greater than 1 and a resistivity in the range of 10 ¹⁰ to 10 ¹² Ωm, so that when the electron beam is hit by an adjacent emitter (+) The charging of the furnace causes distortion of the electrons.

In order to reduce the resistivity value and secondary electron emission coefficient of the spacer of the FED made of only an insulator, the present inventors prepared a spacer based on four conditions of the coefficient of thermal expansion, surface conductivity, durability and reactivity of the spacer or spacer material. Raw materials were selected. As a result, a conventional general insulator powder is prepared, a liquid ink containing a metal component is mixed with the prepared insulator powder, and then the spacer is sintered to form a mixed phase of the insulator and the metal component. In the case of manufacturing a spacer having a specific resistance value in the range of 10 ⁸ ~ 10 ¹⁰ Ωm could be produced spacer close to the secondary electron emission coefficient of 1.

Specifically, the insulating material used in the present invention has a value (8.8 × 10 ⁻⁶ / ° C.) most similar to the coefficient of thermal expansion (8.9 × 10 ⁻⁶ / ° C.) of soda-lime glass used as the upper and lower plate materials of the FED. Alumina (Al ₂ O ₃ ) was used. The alumina satisfies the minimum conditions required for the spacer as an insulator in the range of 10 ¹⁰ to 10 ¹² Ωm surface conductivity.

In the present invention, the conductive solution or paste containing the metal component is preferably a solvent containing a metal such as silver (Ag) or copper (Cu) in a range of 10% by weight to 60% by weight, and the form of the metal. Is more preferably silver nanoparticles (see Fig. 8), or metal particles or metal compounds such as copper.

Accordingly, when the spacer is manufactured from a conductive solution or paste containing an insulator powder and a metal component, an internal structure in which the metal islands are mixed between the insulators can be produced, which is described above. It is possible to provide a minimum path for electrons to move between the same conductors, thereby providing conductivity to the insulator, thereby reducing the resistivity value of the spacer. 5A and 5B are micrographs each showing a mixed phase of a spacer according to an example of the present invention, and as shown here, the inner structure of the spacer is actually a mixed phase in which conductive metal islands are mixed between insulators. can confirm.

As described above, the present invention not only prevents the distortion of the electric field due to the charging of the spacer by reducing the specific resistance value of the spacer, but also disperses metallicity by mixing the metal component with the insulator by using a conductive solution or paste. There is an effect that can produce a high degree of mixed phase.

In addition, in the mixing of the insulator powder and the conductive solution or paste containing the metal component according to the present invention, the conductivity of the spacer may be further increased by increasing the ratio of the metal component to narrow the gap between the metal islands. Through this, the specific resistance value of the spacer can be adjusted according to the composition of the metal component included in the form of a conductive solution or paste. That is, by adjusting the amount of the metal component in the conductive solution or paste to adjust the resistance value of the spacer within the range of 10 ⁸ ~ 10 ¹⁰ Ωm, the secondary electron emission coefficient can also be adjusted close to 1.

Furthermore, as described above, it is also possible to adjust the resistance value of the spacer by adjusting the amount of the metal component to be mixed in the insulator, but in the present invention, the semiconductor oxidation is particularly performed together with the conductive solution or paste including the metal component in the insulator powder. It is possible to further adjust the resistance of the spacer by further including a substance. The semiconducting oxide material used in the present invention is useful because the conductivity of the spacer is not small or extremely large, so that the resistivity of the spacer or the secondary electron emission coefficient can be precisely adjusted even with a small amount. According to this, the spacer according to the present invention may further include a mixed phase of an insulator and a semiconductor oxide material.

Meanwhile, in the present invention, various solvents, binders, surfactants, plasticizers, and the like, in addition to the conductive solution or paste containing the insulator and the metal powder and the semiconductor oxide, By mixing at the ratios shown in Table 1, a green sheet for a spacer can be produced by a tape casting method.

Table 1: Composition and Composition of Spacer

division Material (raw material name) Creation costs Remarks  Solvent   EtOH, MEK, MEK-toluene, etc.  30 ~ 50wt% of powder   Material selection considering polarity and solubility of metal components.  Surfactant   fish oil, Sodium Dodecyl Sulfate, etc.  2 ~ 5wt% compared to powder   Surfactant to help particle dispersion.  Binder   PVB, PVA, Vinyl, Acrylic, Cellulose series, etc.  2 ~ 11wt% of powder   Viscosity, fluidity, plasticity, strength adjustment  Plasticizer   Butylbenzyl phthalate etc.  3 ~ 5wt% compared to powder   Activating Binder  Powder Liquid inks and semiconducting oxides containing Al ₂ O ₃ and metal components   40 ~ 80wt%  Etc  Other clay etc. 0 ~ 1wt% compared to powder   Foaming, lubrication, strength control

As shown in Table 1, the green sheet for manufacturing a spacer according to the present invention is based on a mixture of 40 ~ 80wt% of a conductive solution or paste (possibly including a semiconductor oxide) containing an insulator and a metal component As a solvent, the solvent may be added within the range of 30 to 50 wt% in consideration of the polarity and solubility of the metal component, the surfactant may be added at 2 to 5 wt% according to the degree of dispersion of the particles, and the binder may have a viscosity and fluidity of the slurry. Depending on the plasticity and strength, the plasticizer may be added in an amount of 2 to 11 wt% and 3 to 5 wt% for the activation of the binder.

The green sheet slurry 802 for the spacer having the composition as described above is the green sheet 601 together with the release film 603 using a roll-to-roll type tape caster 604 as shown in FIG. 6. It can be produced as. Subsequently, the green sheet 701 manufactured as described above is cut 702 to a size of a range applicable to a panel using a vacuum micro scope cutting device as shown in FIG. By precisely controlling the profile and firing, the spacer 703 is completed. In addition, it is possible to control the conductivity by stacking two to five sheets having different conductive properties such as insulating sheets and conductive sheets.

The micro spacers manufactured in the form of green sheets are very important because defects generated in the sintering process have a great influence on physical properties such as the strength of the structure. We proceeded this sintering process in the form of three stages: binder decomposition-low melting point temperature material stabilization-complete firing.

Although embodiments of the present invention have been described above with reference to the accompanying drawings, those skilled in the art to which the present invention pertains may implement the present invention in other specific forms without changing the technical spirit or essential features thereof. I can understand that. Therefore, it should be understood that the embodiments described above are exemplary in all respects and not restrictive.

According to the present invention, it is possible to enable the external movement of the charge charged to the spacer through the spacer having a minimum path through which electrons can move inside without being easily charged. In addition, it is possible to produce a large amount of spacers with a high physical strength of secondary electron emission close to 1 without complex and costly post-processing, and to produce a variety of shapes according to the characteristics of the flat panel display device to which the spacer is applied. There is.

1 is a schematic cross-sectional view of a FED panel applied to a conventional micro tip type field emission display,

FIG. 2 is an enlarged cross-sectional view of part A of FIG. 1;

3 is a schematic cross-sectional view of an FED panel having a spacer according to an embodiment of the present invention,

4 is an enlarged cross-sectional view showing a cathode plate of a field emission display according to an example of the present invention;

5A and 5B are micrographs each showing a mixed phase of a spacer according to an example of the present invention,

6 and 7 are schematic views showing a green sheet for manufacturing a spacer according to an example of the present invention and a process of manufacturing the spacer therefrom;

8 is a micrograph of silver nanoparticles contained in a conductive ink according to an example of the present invention.

Claims (5)

In the method of manufacturing a spacer for a field emission display (FED), Preparing an insulator powder, and mixing a conductive solution or paste containing a metal component with the prepared insulator powder, and And sintering the insulator and the metal component to form a mixed phase. The method of claim 1, wherein the conductive solution or paste including the metal component is a solvent including metal particles. The method of claim 2, wherein the metal particles are silver nano particles, copper particles, or metal compounds. delete A field emission device manufactured by the manufacturing method according to any one of claims 1 to 3, comprising a spacer having a specific resistance value in the range of 10 ⁸ to 10 ¹⁰ Ωm.

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