JPH0831349A - Fluorescent character display tube - Google Patents

Abstract

PURPOSE:To provide a fluorescent character display tube equipped with a three- dimensional grid, in which shading of the tube is eliminated using a simple structure and the display quality is enhanced. CONSTITUTION:A fluorescent character display tube includes an anode base board 1, on which a rib 6 made of an insulative material is installed protrusively, and a conductive substance layer 7 is provided at the top of the rib 6 so that a three-dimensional grid G1 is formed, wherein a display pattern is provided with a fluorescent layer 5 formed in the inside surrounded by the grid G1. In this fluorescent character display tube, aux. three-dimensional grid(s) G2 surrounding the display pattern is/are further installed outside the grid G1 positioned at the periphery of the display pattern.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a fluorescent display tube (VFD),
In particular, the present invention relates to a fluorescent display tube having a three-dimensional grid in which a conductive material layer is provided on top of ribs protruding from the anode substrate.

[0002]

2. Description of the Related Art Fluorescent display tubes display a desired pattern by causing thermoelectrons emitted from the cathode to collide with the phosphor on the anode, and a clear and easy-to-see, multi-color display is easy. It has excellent features such as a high degree of freedom and a low operating voltage, and is widely used especially as a display device for automobiles and audio equipment.

In this fluorescent display tube, in order to control the electrons emitted from the cathode, there is provided between the cathode and the anode in Japanese Utility Model Publication No. 57-154059, Japanese Utility Model Publication No. 60-71063, and Japanese Patent Laid-Open No. 60-10663. A triode structure having a grid arranged as described in No. 9040 and the like is often used. By applying a positive voltage to the grid, the electrons emitted from the cathode are accelerated and diffused toward the anode, and conversely, by applying a negative voltage, the electrons toward the anode are blocked and the display is erased. Or

However, since the mesh grid disclosed in the above publication is a bridge shape that is supported by several leg portions and arranged so as to cover the anode, uneven brightness may occur due to thermal deformation during driving. However, problems such as short circuit due to contact with the anode or cathode may occur. Also,
Since the entire surface of the phosphor is arranged so as to be covered with the mesh, a part of the emitted light amount is blocked by the grid skeleton portion which occupies about 8 to 15% of the grid area, resulting in a decrease in the amount of light and uneven brightness. There is.

As a countermeasure against this, for example, JP-A-62-29
Japanese Patent Laid-Open No. 0050) proposes a three-dimensional grid formed higher than the phosphor layer formed on the anode substrate.

This three-dimensional grid comprises an insulating layer formed on a substrate and having a low melting point glass having an insulating property as a main component, and an antistatic resistance formed by adding conductive powder to the low melting point glass formed on the upper surface of the insulating layer. It is composed of three layers, that is, a layer and a conductive layer made of gold, silver or the like disposed on the upper surface thereof.

With such a grid structure, there is no vibration unlike the conventional grid, and there is no display flicker. Further, since there is no obstruction above the phosphor layer, it is possible to obtain an effect such that display is not hindered and display can be performed without lowering the brightness.

[0008]

However, in the one having such a three-dimensional grid structure, the three-dimensional grid is simply formed so as to surround the phosphor, so that another adjacent grid or -20 to- The influence of the electric field due to the insulating layer on the glass substrate charged to 70 V is 60 μm to 1 μm in width.
It is easy to reach the phosphor beyond the 20 μm three-dimensional grid. Since this electric field is a negative electric field, it blocks the electrons emitted from the filament. As a result, in the vicinity of the grid facing the outside of the pattern, electrons are not supplied to the phosphor, and as shown in the explanatory view of FIG. 5, a skimmer that adversely affects the display quality occurs near the outside three-dimensional grid 20. .

Therefore, the problem to be solved in the present invention is to improve the display quality by eliminating the edge of the fluorescent display tube having a three-dimensional grid with a relatively simple structure.

[0010]

In order to solve the above-mentioned problems, the present invention forms a rib made of an insulating material on an anode substrate and forms a conductive material layer on the top of the rib. In a fluorescent display tube having a display pattern in which a three-dimensional grid is formed and a phosphor layer is formed inside the three-dimensional grid, the display pattern is further provided outside the three-dimensional grid located in the outer peripheral portion of the same display pattern. It is characterized in that one or a plurality of surrounding three-dimensional grids are arranged.

Here, the interval between the three-dimensional grid on the outer periphery of the display pattern and the auxiliary three-dimensional grid on the outer periphery is determined by the driving voltage and the grid width. For example, in the case of an anode voltage of 30 V and a grid width of 100 μm, they are adjacent. The influence of the electric field from the grid and the influence of the charge of the insulating layer are canceled by one set of auxiliary solid grids at the same time.
It is desirable that the thickness is about 00 to 200 μm.

When the distance is less than 100 μm, the negative electric field from the adjacent grid extends to the phosphor pattern, resulting in a blush. On the other hand, when the thickness exceeds 200 μm, the influence of the electric charge of the insulating layer between the three-dimensional grid and the auxiliary three-dimensional grid becomes large, and again, the shading easily occurs.

[0013]

By arranging the auxiliary three-dimensional grid on the outer periphery of the display pattern formed by the three-dimensional grid, the negative electric field due to the charge of the insulating layer around the phosphor pattern is canceled by the auxiliary three-dimensional grid, so that the conventional attraction of electrons is thin. The electrons are evenly attracted to the vicinity of the three-dimensional grid on the outer periphery.

[0014]

FIG. 1 is a perspective view of a fluorescent display tube according to an embodiment of the present invention, FIG. 2 is a plan view of its essential portion, and FIG. 3 is a sectional view taken along the line AA of FIG.

1 to 3, 1 is an anode substrate made of glass, 2 is an insulating layer formed on the anode substrate 1 by a thick film printing method and made of a low melting point glass and a color pigment, and 3 is an insulating layer. It is a wiring conductor that connects the conductive layer 4 containing graphite as a main component and the lead pin 13 through a through hole formed in the insulating layer 2.

Referring to FIG. 3, reference numeral 6 denotes an insulating rib having a width of 100 μm formed by a thick film printing method. A conductive material layer is formed on the top of the rib 6 by thick film printing in the same pattern as the rib 6. 7 is formed, and as a result, the three-dimensional grid G is formed.
Forming _one .

The rib 6 is formed by repeating printing and drying 2 to 10 times while ensuring a thickness of 10 to 30 μm in one printing. By dividing and printing in a plurality of steps in this way, it becomes possible to accurately form thin and high ribs vertically.

When forming the insulating rib 6, Japanese Patent Laid-Open No. 3-196441, Sakamoto et al .: "A"
Screen-printing Process
for the Fabrication of Pl
asma DisplayPanels ", Diges
to of Technical Papers, 199
4 Display Manufacturing T
technology Conference, pp. 12
7-130, Atsumi et al .: "Printing Technology for Ultra-High-Definition Plasma Display Panels", Technical Report of the Institute of Electronics, Information and Communication Engineers, EID 89-7, pp. 1989. The printing techniques used to form barrier ribs in plasma display panels, such as those described in 69-71, can be applied.

On the top of the rib 6, a conductive material layer 7 made of aluminum or the like is formed by thick film printing in the same pattern as the rib 6. This conductive material layer 7 functions as a three-dimensional grid G ₁ .

Inside the rib 6, the conductive layer 4 is formed by the thick film printing method during the formation of the rib 6, and the phosphor layer 5 is formed on the upper surface of the conductive layer 4 by the thick film printing method. ing. In this embodiment, the rib thickness is 50 μm, and the protrusion amount from the upper surface of the phosphor layer is 100 μm.

Reference numeral 8 is a grid wiring for energizing the conductive layer 7 formed on the top of the rib 6. The grid wiring 8 is formed on the insulating layer 2 through a through hole (not shown) formed in the grid connecting pad 9 and the insulating layer 2.
Is connected to the grid wiring conductor 16 formed on the back surface of the. Although not shown in detail, it is formed so as to surround the through hole at the end of the grid wiring 8. And
A conductive paste is poured into the grid connection pad 9 and the grid wiring 8 and the grid wiring conductor 1 having different heights are provided.
And 6 are electrically connected. This grid wiring conductor 16
Extend along the back surface of the insulating layer 2 (see FIG. 3).

Further, in this embodiment, as clearly shown in FIGS. 2 and 3, an auxiliary three-dimensional grid G ₂ is provided outside the three-dimensional grid G _{1 in} the outer peripheral portion forming the display pattern so as to surround the display pattern. Is forming.

The auxiliary three-dimensional grid G ₂ is patterned on the same plate as the three-dimensional grid, and is formed simultaneously with the three-dimensional grid G ₁ by the thick film printing method. Furthermore, in order to electrically connect with the three-dimensional grid G ₁ that surrounds the phosphor layer 5, connection grids G ₃ are provided at several places, whereby
The solid grid G ₁ and the auxiliary solid grid G ₂ are driven at exactly the same timing.

In FIG. 1, 12 is a filament, 14 is a filament supporting frame, and 15 is a cover glass.

In the above structure, by applying a positive voltage to each of the three-dimensional grids G ₁ , electrons emitted from the filament 12 are accelerated and diffused to be directed to the conductive layer 4,
On the contrary, by applying a negative voltage, electrons directed to the conductive layer 4 are blocked and the display is erased. At this time, the auxiliary sterically grid G _2, since the same voltage is applied as the three-dimensional grid G _1, at the time of lighting, the negative electric field due to the charge of the phosphor pattern around the insulation layer is applied to the auxiliary stereoscopic grid It will be canceled by the positive voltage.
Therefore, the electrons are evenly attracted to the vicinity of the three-dimensional grid on the outer peripheral portion where the attraction of the electrons has conventionally been thin, and it is possible to perform display without uneven brightness.

FIG. 4 is a graph showing the luminance distribution of the phosphor pattern in the conventional display and the fluorescent display of the present invention. This graph is obtained by measuring the brightness at five points so as to cross one segment of the 8-segment 7-segment phosphor pattern as shown in FIG. 1 along the line BB. The width of the solid grid G _{1 and} the width of the auxiliary solid grid G ₂ are both 0.1 mm, the width of the phosphor layer 5 is 0.4 mm, and the distance between the solid grid G ₁ and the auxiliary solid grid G ₂ is 0.1 m.
m, and the height of the rib is 150 μm. In the conventional fluorescent display tube, as shown in FIG. 4A, the brightness of both widths of the phosphor layer 5 is significantly reduced, whereas in the fluorescent display tube of the present invention, As shown in b), it can be seen that the decrease in the brightness of both widths of the phosphor layer 5 is small. As the conventional fluorescent display tube, the fluorescent display tube shown in FIG. 1 from which the auxiliary three-dimensional grid G ₂ was removed was used.

It should be noted that the present invention is not limited to the above-mentioned 7 segment of the figure 8 shape and the segment of the equalizer pattern, and can be applied to a dot character type, for example. Also in this case, by providing an auxiliary three-dimensional grid on the outer periphery of the three-dimensional grid forming the display pattern,
It is possible to prevent the generation of a lizard that has occurred near the outer circumference.

[0028]

As described above, in the fluorescent display tube of the present invention, one or a plurality of auxiliary three-dimensional grids surrounding the display pattern are arranged outside the three-dimensional grid located at the outer peripheral portion of the display pattern. are doing. As a result, the electrons are evenly attracted to the vicinity of the three-dimensional grid in the outer peripheral portion where the attraction of the electrons has conventionally been thin, and it is possible to display without uneven brightness.

[Brief description of drawings]

FIG. 1 is a partially cutaway perspective view of a fluorescent display tube according to an embodiment of the present invention.

FIG. 2 is a plan view of a main part of the fluorescent display tube shown in FIG.

3 is a cross-sectional view taken along the line AA of FIG.

FIG. 4 is a graph showing a luminance distribution of a phosphor pattern in a conventional display and a fluorescent display tube of the present invention.

FIG. 5 is an explanatory diagram showing a barge of a conventional fluorescent display tube.

[Explanation of symbols]

1 Anode Substrate 2 Insulating Layer 3 Wiring Conductor 4 Conductive Layer (Anode) 5 Fluorescent Material 6 Rib 7 Conductive Material Layer 8 Grid Wiring 11 Lead Pin Connection Pad 12 Filament 13 Lead Pin 14 Filament Support Frame 15 Cover Glass G ₁ Three-dimensional Grid G ₂ Auxiliary solid grid G ₃ connection grid

Claims (1)

[Claims] 1. A rib made of an insulating material is projected on an anode substrate, and a conductive material layer is formed on the top of the rib to form a three-dimensional grid, and a fluorescent material is enclosed inside the three-dimensional grid. In a fluorescent display tube having a display pattern in which a body layer is formed, one or a plurality of auxiliary three-dimensional grids surrounding the display pattern are further arranged outside the three-dimensional grid located on the outer periphery of the display pattern. Fluorescent display tube.