KR20010046087A - Dynamic drive type vacuum fluorescent display - Google Patents

Abstract

PURPOSE: A dynamically driven fluorescent display tube is provided which effectively prevents leakage radiation and simplifies an interconnection line structure by using a conduction barrier wall. CONSTITUTION: A dynamically driven fluorescent display tube includes a pair of substrates(4,6), side glasses(2) placed between the substrates to form a sealed space, and interconnection lines(10) prepared on one of the substrates to electrically connect inner portion of the fluorescent display tube. The fluorescent display tube further has an insulating layer(16) for preventing the interconnection lines from being unnecessarily connected to each other, and a fluorescent material(12) receiving current from the interconnection lines to emit light. The fluorescent display tube also has filaments(8) emitting hot electrons when power is applied to the filaments, and a conductive barrier wall(14) receiving current from the interconnection lines to accelerate or block the hot electrons emitted from the filament to control the light emission of the fluorescent material.

Description

Dynamic Driven Fluorescent Display Tubes {DYNAMIC DRIVE TYPE VACUUM FLUORESCENT DISPLAY}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dynamic drive type fluorescent display tube which controls light emission by a voltage of a conductive layer serving as a grid electrode. More particularly, the present invention relates to a dynamic light which can effectively prevent leakage light emission and simplify a wiring structure. The present invention relates to a driven fluorescent display tube.

In general, a fluorescent display tube (VFD) is a self-luminous display device that selectively emits hot electrons emitted from the filament by colliding with the filament under the control of the grid and the anode, and is excellent in visibility, wide viewing angle, and low voltage. It is easy to apply and has high reliability and is used for various purposes in various fields.

As shown in FIG. 1, the fluorescent display tube is configured to electrically connect the front substrate 102, the rear substrate 104, the side glass 106, and the inside of the fluorescent display tube to form a vacuum container. Except for the wiring 108, the conduction hole formed between the wiring 108 and the conductive layer, the insulating layer 110, which serves to prevent unnecessary electrical conduction of the wiring, and the phosphor is printed and emitted in a predetermined pattern. An anode including a phosphor 112 and a conductor forming a bottom of the phosphor include an anode including a conductive layer 114 for flowing a current through a conducting hole in a wiring 108 and a filament for emitting hot electrons. The filament 116 is installed at a predetermined distance from the anode toward the front substrate 102 and the filament and the predetermined portion below the filament 116 to accelerate or diffuse or block hot electrons emitted from the filament 116. The left consists of a metal mesh (mesh), a grid 118 of the type that is installed.

Accordingly, when voltage is applied to the filament 116 and the grid 118 and the anode, the anode exhibits the characteristics of the circuit anode, and the hot electrons emitted while the filament 116 is heated are accelerated and diffused by the grid 118. Then, the phosphor collides with the phosphor 112 of the anode, and the phosphor emits light, and the emitted light is irradiated to the outside through the front substrate 102 so that an image such as a predetermined letter or symbol is realized.

The fluorescent display tube configured as described above is classified into a static drive type for canceling light emission by an anode voltage and a dynamic drive type for canceling light emission by a grid voltage according to a driving method. do.

That is, the static driving method applies a negative voltage (or a voltage lower than the filament potential) to the anode so that the phosphor does not emit light even when hot electrons emitted from the filament 116 collide with the phosphor 112, thereby eliminating light emission. In this driving scheme, only the grid accelerates hot electrons, and a driving voltage is always applied to the grid.

In addition, the dynamic driving method applies a negative voltage (or a voltage lower than the filament potential) to the grid 118 to cancel the light emission by blocking the hot electrons so that the hot electrons emitted from the filament do not reach the phosphor 112. In the driving method, the grid accelerates or blocks hot electrons, and a driving voltage is always applied to the anode.

As described above, the plurality of phosphors constituting the dot or segment format are individually driven according to voltages applied to the anode and the grid to express specific letters or numbers.

However, according to the fluorescent display tube to which the mesh type grid configured as described above is applied, there are the following problems.

First, since the mesh type grid is expensive, the manufacturing cost of the fluorescent display tube is increased, and since the grid covers the entire surface of the phosphor, a predetermined amount of the hot electrons is absorbed by the grid when the electrons emitted from the filament pass through the grid. Is not preferable, and the emitted light of the phosphor is blocked by the grid, whereby the luminance is lowered.

Further, when the fluorescent display tube is driven, the grid is thermally deformed by hot electrons, causing luminance unevenness.

In order to solve this problem, in recent years, insulating ribs are formed at a predetermined height around the anode, and a conductive liquid is printed on the upper surface of the partitions to form a conductive layer, and the conductive layer acts as a grid. A fluorescent display tube has been proposed.

This will be described with reference to FIG. 2.

In the above-described conventional example, since the basic structure of the fluorescent display tube is the same as that of the fluorescent display tube of FIG. 1, only the insulating partition wall and the conductive layer will be described here.

As shown in the figure, an insulating partition wall 118'a is provided around each anode composed of the conductive layer 114 and the phosphor 112 at a height of about 100 to 150 mu m, and the upper side of the partition wall 118'a. On the surface, a conductive layer 118'b made of conductive liquid is provided with a thickness of 10 to 15 mu m.

The barrier rib 118'a and the conductive layer 118'b are typically formed by a thick film printing method. In the thick film printing, the barrier rib prints an insulating liquid with a thickness of 10 to 30 μm, and after drying it, The process is repeated 3 to 15 times.

In a dynamic drive fluorescent display tube having such a structure, when a negative voltage (cut-off voltage) is applied to the conductive layer 118'b, hot electrons are formed through the space between the conductive layers. Since it is impossible to reach 112, the dynamic driving of the fluorescent display tube is possible by controlling the voltage applied to the conductive layer 118'b.

However, the conventional fluorescent display tube constructed as described above has the following problems.

First, in order to drive the fluorescent display tube dynamically, an insulating partition wall needs to be printed at a height of about 100 to 150 μm and a conductive layer is printed thereon, which requires a lot of time for the print job and the print job is repeated several times. Cumbersome.

When hot electrons emitted from the filament are accelerated to the phosphor by the conductive layer during driving of the fluorescent display tube, a part of the hot electrons are interposed between adjacent conductive layers (conductive layer to which a cutoff voltage is applied and conductive layer to which a driving voltage is applied). The hot electrons charged to the insulating layer are leaked from a portion (part A) of the phosphor between the conductive layers to which the cutoff voltage is applied through the insulating partition wall to the anode to which the driving voltage is continuously applied. There is a problem that light emission occurs.

That is, in the conventional fluorescent display tube, leakage light caused by the hot electrons can be prevented by blocking hot electrons that collide with the phosphor by passing through the space between the conductive layers to which the cutoff voltage is applied, but driving with the conductive layer to which the cutoff voltage is applied. Leakage emission caused by hot electrons charged to the insulating layer between the conductive layers to which voltage is applied cannot be prevented.

In addition, since the conductive layer is provided on the upper surface of the insulating partition wall, the wiring structure for applying a voltage to the conductive layer becomes complicated, resulting in an increase in the number of working hours.

Accordingly, an object of the present invention is to provide a dynamic drive type fluorescent display tube which can effectively prevent leakage light emission and simplify a wiring structure.

1 and 2 are cross-sectional views of a fluorescent display tube according to the prior art.

3 is a cross-sectional view of a fluorescent display tube according to the present invention;

The object of the present invention as described above,

A side glass positioned between the pair of substrates and the substrates to form a closed space;

Wirings provided on at least one of the substrates to electrically connect the inside of the fluorescent display tube;

An insulating layer for preventing unnecessary energization between wirings;

A phosphor that emits light by receiving current from the wiring;

A filament installed in a tension state on the support to emit hot electrons when the power is applied;

A conductive partition wall formed around the phosphor by a predetermined height and configured to control light emission of the phosphor by accelerating or blocking hot electrons emitted from the filament by receiving a current from the wiring;

It is achieved by a dynamic drive type fluorescent display tube comprising a.

Here, the conductive partition wall is provided at a height of 30 µm or more, in particular 60 µm or more from the upper surface of the phosphor, and the phosphor and the conductive partition wall are printed directly on the surface of the wiring.

According to a preferred embodiment of the present invention, according to the height of the conductive partition wall, each of the appropriate cutoff voltage that can prevent the leakage light emission is presented.

That is, when the grid and anode electrode driving voltage is 25V _PP , the duty is 1/5, the width of the conductive barrier rib is 200 μm, the width of the phosphor is 300 μm, the width of the wiring is 400 μm, and the printing interval between the conductive barrier ribs is 800 μm. If the height of the conductive barrier is 30 μm, the cutoff voltage is 7 V or more. If the height of the conductive barrier is 40 μm, the cutoff voltage is 6 V or more. If the back cutoff voltage is 0V or more, leakage light emission is prevented.

The fluorescent display tube of the present invention having the above characteristics can reliably prevent leakage of phosphors, while reducing the number of operations compared to the conventional fluorescent display tubes and simplifying the wiring structure.

Hereinafter, a fluorescent display tube according to a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

3 illustrates a cross-sectional view of a fluorescent display tube according to the present invention.

As shown in the figure, the fluorescent display tube is fixed at both ends by a front support 4 and a back substrate 6 bonded by the side glass 2 and a support so as to cross the inside of the container formed by these substrates. A plurality of filaments 8, a wiring 10 for electrically connecting the inside of the fluorescent display tube, a phosphor 12 provided on the surface of the wiring 10 to form a predetermined display pattern, and a phosphor 12 Conductive partition wall 14 provided at a predetermined height from the upper surface of the phosphor in the vicinity of the, and an insulating layer 16 that serves to prevent unnecessary electrical conduction of the wiring.

Here, the wiring 10 includes an anode electrode for applying a voltage waveform to the phosphor, and a grid electrode for applying a voltage waveform to the conductive partition wall.

In addition, the conductive partition wall 14 emits the phosphor 12 by accelerating the hot electrons emitted from the filament 8 and colliding with the phosphor 12 when power is applied through the wiring 10, or the filament In addition to blocking hot electrons emitted from (8) from colliding with the phosphor 12 and preventing leakage light emission due to hot electrons charged to the insulating layer between the partition walls, Ag, Al, carbon, etc. The conductive material is formed by printing on the surface of the wiring 10 at a predetermined height (30 µm or more from the upper surface of the phosphor) by a thick film printing method.

When the thick film printing method is used, the conductive partition wall can be formed by printing and drying at least once with a thickness of about 25 µm.

Table 1

Driving voltage Conductive bulkhead width (W ₁ ) Phosphor Width (W ₂ ) Wiring layer width (W ₃ ) Spacing between Conductive Bulkheads (L) Conductive bulkhead height (H) Cutoff voltage Leakage 25V _PP Duty: 1/5 200 μm 300㎛ 400 μm 800 ㎛ 30 μm 6V or less radiation 7V or more Non-luminous 40 μm 5V or less radiation 6V or more Non-luminous 50 μm 4V or less radiation 5V or more Non-luminous 60㎛ 0V or more Non-luminous 70㎛ 0V or more Non-luminous 80㎛ 0V or more Non-luminous

Table 1 shows a diagram of experiments on whether or not leakage light of the phosphor 12 according to the height (H) from the upper surface of the phosphor to the upper surface of the conductive partition wall 14, the leakage light emission is referred to as the conductive partition wall 14 Refers to a state in which the phosphor emits light even though the cutoff voltage is applied), and the leakage light emission refers to leakage light emitted by hot electrons passing through a space between the conductive partition walls to which the cutoff voltage is applied, and a conductive partition wall to which the cutoff voltage is applied. Leakage light due to hot electrons charged to the insulating layer between the conductive barrier wall to which the driving voltage is applied.

However, in the present invention, since the partition wall is formed of a conductive liquid, the hot electrons charged to the insulating layer do not pass through the partition wall to which the cutoff voltage is applied due to the electric force of the repulsive force acting between the same polarity, and are applied to the partition wall to which the driving voltage is applied. Since it disappears, leakage light emission by the hot electrons charged to the insulating layer is surely prevented.

Therefore, the above experiment is data for only leakage light emitted by hot electrons passing through the space between the conductive partition walls to which the cutoff voltage is applied. In the experiment, the anode and grid driving voltage (25V _PP , duty 1/5) The width of the conductive partition wall (200 µm), the phosphor width (300 µm), the wiring width (400 µm), and the printing interval (800 µm) between the conductive partition walls were set in the same manner.

Referring to Table 1, when the anode and grid electrode driving voltage, the conductive partition wall width W ₁ , the phosphor width W ₂ , the wiring width W ₃ , and the distance L between the conductive partition walls are set as described above, If the height H of the conductive barrier rib is 30 μm, the cutoff voltage is 7 V or more. If the height of the conductive barrier rib is 40 μm, the cutoff voltage is 6 V or higher. If the height of the conductive barrier rib is 50 μm, the cutoff voltage is 5 V or higher. If the thickness is 60 占 퐉, the occurrence of leakage is prevented when the cutoff voltage is 0 V or more.

As such, when the conductive barrier ribs are formed at a height of 30 μm or more from the upper surface of the phosphor, leakage can be prevented by gradually increasing the value of the cutoff voltage. In particular, the conductive barrier ribs are formed at a height of 60 μm or more. In this case, it is possible to reliably prevent the occurrence of leakage without regard to the magnitude of the cutoff voltage under the above conditions (driving voltage, phosphor width, wiring width, printing gap between conductive partitions).

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.

As described above, according to the fluorescent display tube of the present invention, by using the conductive partition wall, it is possible to prevent the leakage light emission of the adjacent phosphor due to the hot electrons charged to the insulating layer, and by providing the appropriate height of the conductive partition wall appropriate cutoff characteristics It is possible to obtain the structure, and the wiring structure can be simplified by printing the phosphor and the conductive partition directly on the surface of the wiring.

Claims (9)

A side glass positioned between the pair of substrates and the substrates to form a closed space; Wirings provided on at least one of the substrates to electrically connect the inside of the fluorescent display tube; An insulating layer for preventing unnecessary energization between wirings; A phosphor that emits light by receiving current from the wiring; A filament installed in a tension state on the support to emit hot electrons when the power is applied; A conductive partition wall formed around the phosphor by a predetermined height and configured to control light emission of the phosphor by accelerating or blocking hot electrons emitted from the filament by receiving a current from the wiring; Dynamic driven fluorescent display tube comprising a. The fluorescent display tube of claim 1, wherein the conductive partition wall is provided at a height of 30 μm or more from an upper surface of the phosphor. The fluorescent display tube according to claim 2, wherein the height of the conductive partition wall is particularly 60 µm or more. 4. A dynamic drive fluorescent display tube according to any one of claims 1 to 3, wherein said phosphor is provided on a surface of said wiring. The dynamic drive type fluorescent display tube according to any one of claims 1 to 3, wherein said conductive partition wall is provided on a surface of said wiring. The width of the conductive partitions is 200 µm, the width of the phosphor is 300 µm, the width of the wiring is 400 µm, the printing interval between the conductive partitions is 800 µm, and the height of the conductive partitions is 30 µm. And a cutoff voltage of 7 V or more when the driving voltage of the anode and the grid electrode is driven at 25 V _PP and the duty is 1/5. The width of the conductive partitions is 200 µm, the width of the phosphor is 300 µm, the width of the wiring is 400 µm, the printing interval between the conductive partitions is 800 µm, and the height of the conductive partitions is 40 µm. And a cutoff voltage of 6 V or more when the driving voltage of the anode and the grid electrode is driven at 25 V _PP and the duty is 1/5. The width of the conductive partitions is 200 µm, the width of the phosphor is 300 µm, the width of the wiring is 400 µm, the printing interval between the conductive partitions is 800 µm, and the height of the conductive partitions is 50 µm. And a cut-off voltage of 5 V or more when the driving voltage of the anode and the grid electrode is driven at 25 V _PP and the duty is 1/5. The width of the conductive partition wall is 200 µm, the width of the phosphor is 300 µm, the width of the wiring is 400 µm, the printing interval between the conductive partition walls is 800 µm, and the height of the conductive partition wall is 60 µm. A dynamic driving fluorescent tube having a cutoff voltage of 0 V or more when the driving voltage of the grid electrode is driven at 25 V _PP and the duty is 1/5.