KR20020068931A - Vacuum fluorescent display device - Google Patents

Abstract

PURPOSE: A vacuum fluorescent display is provided to prevent lighting spot of a phosphor layer and contrast and life span from lowering due to residual gas of vessel interior. CONSTITUTION: A vacuum fluorescent display comprises a pair of substrates forming a vacuum vessel with a side glass, a wiring(8) mounted on at least one of the substrates to connect electrically an inside of a tube, an insulation layer(12) forming a conduction hole(10), a filament mounted inside of the vacuum vessel and emitting thermal electron on voltage applying, a conductive layer(14) electrically connected to the wiring through the conduction hole, a phosphor layer(18) mounted on the surface of the conductive layer and excited by the thermal electron, an insulation rib(20), and a control electrode for controlling the emitted thermal electron. The conduction hole is formed at a low side of the insulation rib.

Description

Fluorescent Display Tube {VACUUM FLUORESCENT DISPLAY DEVICE}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluorescent display tube having a rib grid, and more particularly, to prevent light emission stains of fluorescent layers due to electron density, and to prevent deterioration in luminance characteristics and lifetime due to residual gas inside the container. The present invention relates to a fluorescent display tube which can reduce the number of manufacturing processes.

The fluorescent display tube (VFD) is a self-luminous display element that selectively collides the hot electrons emitted from the filament with the fluorescent layer under the control of the control electrode and the anode electrode and emits light, and is excellent in visibility, wide viewing angle, and can be driven at low voltage. It has high reliability and is used for various purposes in various fields.

As an example of such a fluorescent display tube, a fluorescent display tube employing a metal mesh type mesh grid is disclosed as a control electrode for controlling hot electrons emitted from a filament (cathode electrode).

The control electrode is formed by etching a thin iron piece of SUS material to form a mesh and providing a support on the periphery of the mesh, the support is to support the mesh to a certain height for the control of electrons emitted from the filament do.

Accordingly, when the mesh grid is installed on the substrate, between the patterns of the support and the anode electrode, and adjacent to each other, in order to ensure that the hot electrons reach the end of the fluorescent layer satisfactorily, and to prevent leakage light emission of adjacent fluorescent layers, respectively. Since a constant distance between the mesh grids must be secured, the fluorescent display tube having the mesh grid is disadvantageous for the fine pattern design, and there is a problem that it cannot be applied to the complex polygonal pattern.

In addition, the mesh grid may sag in the center of the mesh due to thermal deformation during manufacturing and use, and in this case, the ability to accelerate and diffuse electrons may be degraded, resulting in a difference in luminance from a fluorescent layer inside an adjacent mesh grid. .

Therefore, in order to prevent the deflection of the center portion is necessary to increase the number of support is also a cause to inhibit the free pattern design of the anode electrode.

In order to solve this problem, Japanese Patent Laid-Open No. 6-251732 discloses a rib grid for fluorescent display tubes.

Referring to FIG. 1, the anode substrate 110 is provided with a wiring 112 electrically connecting the inside of the display tube and an insulating layer 114 to prevent unnecessary conduction between the wirings 112 and the wiring 112. ) Is provided on the conductive layer 116 through which the wiring 112 is energized, and on the conductive layer 116 is provided a fluorescent layer 118 that is excited and emitted by hot electrons emitted from a filament (not shown).

Here, the conductive layer 116 and the fluorescent layer 118 constitute an anode electrode.

An insulating rib 120 is provided around the conductive layer 116 at a height of about 100 to 150 µm, and an upper surface of the rib 120 is formed of a conductive material such as Ag, Al, Ni, or carbon. The conductive ribs 122 are provided in a thickness of 10 to 15 mu m.

Here, the insulating ribs 120 protrude at least 20 μm from the top surface of the fluorescent layer 118 to prevent a short circuit between the conductive ribs 122 and the fluorescent layer 118.

However, in the fluorescent display tube having the rib grid having such a structure, since the insulating rib 120 is formed higher than the fluorescent layer 118, the negative charge charged on the surface of the insulator layer outer periphery of the insulating rib 120 is prevented. Electron density is uneven due to the generated electric field, which causes light emission stains on the fluorescent layer 118.

In order to solve this problem, Japanese Patent Laid-Open No. 8-138591 discloses a fluorescent display tube having an outer electrode.

Referring to FIG. 2, the anode substrate 130 is provided with a wiring 132, an insulating layer 134, a conductive layer 136, and a fluorescent layer 138, and conducts around the fluorescent layer 138. The layer 136 is provided with an insulating rib 140 higher than the fluorescent layer 138 by about 100 to 150 μm, and the upper surface of the rib 140 is formed of a conductive material such as Ag, Al, Ni, or carbon. The conductive ribs 142 are provided with a thickness of 10 to 50 mu m.

The auxiliary grids 140 ′ and 142 ′ having the same pattern as the rib grids 140 and 142 are provided around the conductive layer 136.

In this case, the conductive layer 136 serves as an outer circumferential electrode to prevent light emission from being generated in the fluorescent layer 138 by removing negative (-) charges charged on the surface of the insulator layer.

However, according to the prior art of the above configuration, there are the following problems.

That is, the rib grid of the conventional fluorescent display tube is formed by repeating the process of printing the insulating paste to a thickness of 10 to 30㎛ and drying it 3 to 15 times, and printing the thick film in the same pattern on the upper surface of the insulating rib in the same pattern. To form.

Therefore, the printing operation needs to be repeated several times to form the ribs, which requires a lot of time for the printing operation, and the gas generated from the conductive material remains in the vacuum container, and the flow of electrons is interrupted by this residual gas, or the residual There is a problem that gas is adsorbed on the surface of the filament or the fluorescent layer so that the luminance characteristic is lowered and the life of the fluorescent display tube is lowered.

In the conventional fluorescent display tube, since the wiring for electrically connecting the inside of the display tube is located directly under the fluorescent layer, and the anode voltage is applied to the wiring, the electron density is high in the fluorescent layer portion directly above the wiring. It is high and the electron density is low in another fluorescent layer part compared with the said part.

Therefore, there is a problem that light emission unevenness occurs due to the nonuniformity of the electron density.

Thus, in order to solve the above problems, the present invention can prevent the light emission stain of the fluorescent layer due to the electron density, and can prevent the luminance characteristics and life from being lowered due to the residual gas inside the container, and the number of manufacturing steps It is an object of the present invention to provide a fluorescent display tube that can be reduced.

1 is a view showing the main part of a fluorescent display tube according to an embodiment of the prior art.

2 is a view showing a main part of a fluorescent display tube according to another embodiment of the prior art;

3 is an exploded perspective view of a fluorescent display tube according to the present invention;

4 is a cross-sectional view of an essential part of FIG. 3.

FIG. 5 is a sectional view of principal parts showing a modified embodiment of FIG. 3; FIG.

FIG. 6 is a schematic diagram illustrating a method of manufacturing the metal rib of FIG. 5. FIG.

FIG. 7 is an essential part cross sectional view showing another modified embodiment of FIG. 3; FIG.

The object of the present invention as described above,

A pair of substrates which together with the side glass constitute a vacuum container;

Wiring provided on at least one of the substrates to electrically connect the inside of the tube;

An insulating layer for forming an energizing hole and preventing unnecessary energization between the wires;

A filament mounted inside the vacuum container and emitting hot electrons when the power is applied;

A conductive layer electrically connected to the wiring through the conduction hole, and a fluorescent layer provided on the surface of the conductive layer and excited by the hot electrons to emit light;

A control electrode comprising an insulating rib provided on the surface of the conductive layer around the fluorescent layer and a conductive rib provided on the upper surface of the insulating rib to control hot electrons emitted from the filament;

It includes, the conducting hole is provided on the lower side of the insulating rib.

Preferably, the conductive ribs are made of a single layer of metal material having high electrical conductivity.

In the fluorescent display tube having such a configuration, since the conduction hole is provided below the insulating ribs instead of the fluorescent layer, it is possible to improve light emission unevenness due to electron density.

In addition, since the control electrode for controlling the hot electrons is made of metal ribs, the manufacturing process can be simplified compared to the prior art of forming a rib grid by printing a thick film of insulating and conductive pastes, thereby reducing labor and generating gas due to the conductive pastes. By minimizing this, the quality and lifespan characteristics of the fluorescent display tube can be improved.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

3 is an exploded perspective view of a fluorescent display tube according to the present invention, and FIG. 4 is a cross-sectional view of an essential part of FIG. 3.

The fluorescent display tube has a side glass 2 and a front substrate 4 and a rear substrate 6 constituting a vacuum container.

The rear substrate 6 is provided with a wiring 8 for electrically connecting the inside of the display tube, and an insulating layer 12 for forming an energization hole 10 and preventing unnecessary power supply between the wirings 8. A conductive layer 14 electrically connected to the wiring 8 is provided on the wiring 8, and on the conductive layer 14, a fluorescent layer 18 excited and emitted by hot electrons emitted from the filament 16. This is provided.

Here, the conductive layer 14 may be formed by forming a separate dot layer (not shown) inside the conduction hole 10 to conduct electricity with the wiring through the dot layer, or at the time of printing the conductive layer 14 The conductive paste may be filled in the conduction hole 10 to directly conduct the conductive layer 14 and the wiring 8.

In this case, the present invention is formed so that the conduction hole 10 is located below the conductive layer 14 at a point away from the lower side of the fluorescent layer 18.

As such, when the conduction hole 10 is formed at the position, a uniform electric field is formed in the fluorescent layer 18, thereby preventing light emission from the electrons.

And, a control electrode is provided on the surface of the conductive layer 14, the control electrode is in contact with the side of the fluorescent layer 18 and the insulating rib 20 is formed higher than the fluorescent layer 18 and And a metal rib 22 provided on the surface of the rib 20.

The insulating ribs 20 may be formed to have a thickness of about 30 to 100 μm to prevent electric current between the metal ribs 22 and the anode electrodes 14 and 18, and preferably the upper surface of the fluorescent layer 18. From 10 to 20 μm.

Here, the height of the insulating rib 20 can be variously designed within the above range depending on the structure of the product, the power supply conditions, the dimensions of the display pattern, the height of the metal ribs.

The metal ribs 22 control the light emission of the fluorescent layer 18 by accelerating or blocking hot electrons emitted from the filament 16. The metal ribs 22 are formed of a single layer metal material having high electrical conductivity, for example, stainless steel. Or, it may be made of a material having a higher electrical conductivity than the stainless steel, for example, platinum, silver, copper or the like depending on the product characteristics.

As a method for applying power to the metal ribs 22 having such a configuration, a wiring terminal pin portion (not shown) that reaches the lead pad 24 is formed integrally with the ribs 22 and through the wiring 8. A method of receiving external power and a method of forming a lead pin portion (not shown) extending outwardly of the substrate 6 integrally with the ribs 22 so as to receive external power without passing through the wiring 8. In this case, the wiring terminal pin portion and the lead pin portion is preferably formed to be less than the thickness of the metal rib (22).

As a result, the metal rib 22 functions as a grid electrode that accelerates or blocks hot electrons emitted from the filament 16 when power is applied.

In addition, the metal ribs 22 are formed to have an easy height for electronic control, and are generally formed higher than the anode electrode using a metal material of about 0.05 to 0.25 tons, and preferably 50 to 300 from an upper surface of the fluorescent layer 18. The thickness is formed to be high, particularly about 180 to 200 m.

Here, the height of the metal ribs 22 may be variously adjusted according to product characteristics within the above range.

The metal rib 22 of such a structure can be manufactured as follows, for example.

First, a metal material having a width corresponding to the area of the anode electrode unit to be covered and a predetermined thickness capable of electronic control is prepared. Then, a part of the metal material is etched and removed by a known photolithography process to complete a metal rib of a specific pattern.

The control electrode is completed by attaching the completed metal rib 22 to the upper surface of the insulating rib 20 while being electrically connected to the wiring 8.

Meanwhile, the metal ribs 22 may be formed in various patterns according to design specifications, in addition to the illustrated embodiment, and a portion for enclosing the energization portion and the anode electrode for energization with the wiring 8 may also be formed according to product characteristics. Deformation of the shape is possible.

5 shows a modified embodiment of the metal ribs, and the same reference numerals are used for the same components as the previous embodiment.

In the metal rib 26 according to the present exemplary embodiment, as the area of the anode electrodes 14 and 18 increases, the influence on the center portion of the anode electrode decreases, thereby preventing the luminance and cut-off characteristics of the fluorescent layer 18 from being lowered. For this purpose, the upper end of the rib 26 is provided with an extension portion 26 'extending vertically toward the inside of the anode electrode.

As a result, the planar area of the ribs 26 is enlarged as compared with the previous embodiment, so that even when the anode electrode is patterned with a large area, the electronic control function is satisfactorily due to the smooth functioning of the metal ribs 26. You lose.

At this time, the extension portion 26 'of the metal ribs 26 is formed so as not to overlap the fluorescent layer 18 substantially so as not to cover the display pattern by the fluorescent layer 18.

The metal ribs 26 having the extensions 26 'are patterned with the photoresist film 30 on the surface of the metal material 28 to have the extensions 26', as shown in FIG. In addition, an etching solution is simultaneously added to both surfaces of the metal material 28 and can be easily produced by double etching.

The fluorescent display tube having such a configuration is preferably formed so that the space between adjacent conductive layers and the space between adjacent metal ribs are kept at least 50 µm or more.

On the other hand, when the width of the insulating ribs provided on the surface of the conductive layer is very narrow for product design reasons, as shown in Fig. 7, the insulating ribs 20 'are integrated into one piece to be printed, and the insulating ribs 20' are formed. It is also possible to form the metal ribs 22 or 26 on the surface of the substrate in a state spaced apart by a predetermined interval, respectively.

As described above, the fluorescent display tube of the present invention provides a control electrode made of an insulating rib and a metal rib on the surface of the conductive layer, and forms a conducting hole for electrically connecting the wiring and the conductive layer to the lower side of the insulating rib. A uniform electric field can be formed, and various problems caused when printing the conductive paste to form the conductive ribs can be eliminated.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited thereto, and various modifications and changes can be made within the scope of the claims and the detailed description of the invention and the accompanying drawings. Naturally, it belongs to the range of.

The fluorescent display tube according to the present invention configured as described above has the following effects.

Since a conduction hole for electrically connecting the wiring and the conductive layer is formed at a point away from the lower side of the fluorescent layer, a uniform electric field is formed in the fluorescent layer as a whole to prevent light emission from the electron density.

In addition, metal ribs made of a metal material can shorten the labor time compared to conventional conductive ribs formed by repeatedly printing a conductive paste several times, and do not require printing and firing operations. And it is possible to prevent the shortage of life due to short-lived and repeated printing can be improved the yield of the fluorescent display tube.

In addition, since the electrical conductivity of the metal rib is much higher than that of the conventional conductive rib formed by repeatedly printing the conductive paste, it is possible to more efficiently control the hot electrons emitted from the filament, and the metal rib having the extension part has a wide anode electrode. Even when the area is patterned, the luminance and cut-off characteristics of the fluorescent layer can be prevented from being lowered.

In addition, since a control electrode made of an insulating rib and a metal rib is provided on the surface of the conductive layer, the electrode height is compensated as much as the thickness of the conductive layer, thereby reducing the number of prints for forming the insulating rib and freeing the pattern. It can improve the degree of density and solve the problem that the emitted light of adjacent phosphors is reflected from the metal ribs.

Claims (9)

A pair of substrates which together with the side glass constitute a vacuum container; Wiring provided on at least one of the substrates to electrically connect the inside of the tube; An insulating layer for forming an energizing hole and preventing unnecessary energization between the wires; A filament mounted inside the vacuum container and emitting hot electrons when the power is applied; A conductive layer electrically connected to the wiring through the conduction hole, and a fluorescent layer provided on the surface of the conductive layer and excited by the hot electrons to emit light; A control electrode comprising an insulating rib provided on the surface of the conductive layer around the fluorescent layer and a conductive rib provided on the upper surface of the insulating rib to control hot electrons emitted from the filament; And a conductive hole provided below the insulating rib. The fluorescent display tube according to claim 1, wherein the conductive ribs are made of a single layer metal material having high electrical conductivity. 3. The fluorescent display tube according to claim 2, wherein the metal rib made of the metal material is formed by etching the metal material in a predetermined pattern. 3. The fluorescent display tube according to claim 2, wherein the metal rib made of the metal material is made of any one metal material selected from stainless steel, platinum, silver or copper. The fluorescent display tube according to claim 2, wherein the metal rib made of the metal material is formed to be about 50 to 300 mu m high from an upper surface of the fluorescent layer. The fluorescent display tube of claim 2, wherein the metal ribs made of the metal material surround each segment constituting the anode electrode unit. The fluorescent display tube according to claim 6, wherein one insulating rib is provided between two adjacent segments, and the surface of the insulating rib is provided with two metal ribs for controlling the segments on both sides, spaced apart by a predetermined interval. . 3. The fluorescent display tube according to claim 2, wherein the metal rib made of the metal material is provided with an extension portion in which an upper end of the rib extends vertically toward the inside of each anode electrode. The fluorescent display tube according to claim 1 or 2, wherein the insulating ribs are provided to be in contact with a side surface of the fluorescent layer.