JP2822761B2 - Fluorescent display tube - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluorescent display tube, and more particularly to a fluorescent display tube for graphic display in which phosphors are arranged in a matrix.

[0002]

2. Description of the Related Art A fluorescent display tube for graphic display is shown in FIG.
As shown in FIG. 2, phosphor dots 2 arranged in a matrix on the anode electrode 1 and wire grids 3 arranged on both sides of the phosphor dots 2 in a direction orthogonal to the anode electrode 1, are orthogonal to the grid 3. In this configuration, several filaments 4 are arranged in the direction in which the filaments 4 are formed. The phosphor dots 2, the grid 3, and the filament 4 have a three-dimensional structure spaced apart so as not to contact each other.

In order to drive this graphic display fluorescent display tube, the filament 4 is always heated and emits thermoelectrons, and as shown in FIG. In this figure, G1, G2, G
2 and G3) at the same time, and sequentially select them from left to right or right to left (G1, G2,
(In the order of G3...), And when scanning is completed, scanning is repeated from the beginning.

The grids 3 on both sides of the phosphor dots 2 to be illuminated add a signal for driving the anode electrode (An in this figure) in accordance with the selected timing and repeat this in accordance with the scanning of the grid 3.

In the example of FIG. 1, the timing is such that the phosphor dots 2 between G1 and G2 and between G3 and G4 are turned on.

A desired display can be obtained by repeating the scanning for one screen at least 60 times per second.

[0007]

FIG. 8 is a partially enlarged plan view of the phosphor dot portion of FIG.

[0008] As shown in FIG. 8, the number of filaments 4 is usually one at a rate of 5 to 6 phosphor dots 2.

FIGS. 9A and 9B are a schematic view of an electron beam emitted from a filament of a conventional fluorescent display tube for graphic display and a current density distribution diagram thereof.

As shown in FIGS. 9 (a) and 9 (b), there is a difference in the distance between each of the phosphor dots 2 and the filament 4, and the electrons emitted from the filament 4 are farther from the part closer to the filament 4. There is a difference in the amount of arrival between the phosphor dots 2 of the part.

This difference in the amount of electrons appears as a difference in the brightness of the phosphor dots 2 and causes a problem of impairing the uniformity of the display brightness.

If the number of filaments 4 is increased for this measure, the power consumed by the filaments 4 will increase.

An object of the present invention is to provide a graphic display fluorescent display tube having excellent display uniformity without increasing power consumption.

[0014]

SUMMARY OF THE INVENTION The present invention is directed to a phosphor layer arranged in a matrix in a vacuum vessel, a linear grid arranged on both sides of the phosphor layer, and a linear grid arranged in a direction perpendicular to the grid. (1) A linear grid parallel to the filament is arranged between the filament and the filament.

(2) The size of the phosphor layers arranged in a matrix increases as the distance from the filament increases, and the size immediately below the filament is smallest.

(3) A linear grid parallel to the filament is arranged between the filaments, and the phosphor layers arranged in a matrix become larger as the distance from the filament increases. The area directly below the filament is the smallest.

[0017]

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a partially cutaway perspective view of a first embodiment of the present invention, and FIG. 2 is a partially enlarged plan view of the phosphor dot portion of FIG.

In the first embodiment, as shown in FIGS. 1 and 2, an anode electrode 1 is disposed on an anode substrate 6, and phosphor dots 2 are formed on the anode electrode 1 in a matrix. I have. On both sides of the phosphor dot 2, a wire grid 3 is arranged in a direction orthogonal to the anode electrode 1, and several filaments 4 are arranged in a direction orthogonal to the grid 3. Further, a linear grid 5 is stretched between the filaments 4 in a direction parallel to the filament 4 and at an intermediate height between the filament 4 and the grid 3.

The phosphor dots 2, grids 3, filaments 4 and linear grids 5 are spaced apart so as not to contact each other.

FIGS. 3A and 3B are a schematic view of an electron beam emitted from the filament of the first embodiment of the present invention and a current density distribution diagram thereof.

As shown in FIGS. 3A and 3B, the linear grid 5 is stretched between the filaments 4 in a direction parallel to the filaments 4 and at an intermediate height between the filaments 4 and the grids 3. Although the electrons emitted from the filament 4 are attracted and accelerated by the grid 3, by applying a voltage for attracting the electrons to the linear grid 5, FIG.
Compared with the conventional fluorescent display tubes shown in FIGS. 1A and 1B, the amount of electrons reaching each phosphor dot 2 is made uniform, and a fluorescent display tube with excellent display quality can be obtained.

In the first embodiment, the size of the phosphor dots 2 is 0.3 × 0.3 mm, the pitch is 0.45 mm, the distance from the anode substrate 6 to the grid 3 is 0.4 mm, and the distance between the grid 3 and the filament 4 is 0.4 mm. Distance 1.0mm, filament 4
When the pitch between them is 2.25 mm, the distance from the grid 3 to the linear grid 5 parallel to the filament 4 is set to 0.8 mm.
When 12 V was applied, excellent uniformity of luminance was realized.

FIG. 4 is a partially enlarged plan view of a phosphor dot portion according to a second embodiment of the present invention, and FIGS. 5A and 5B are electron beams emitted from a filament according to the second embodiment of the present invention. And a current density distribution diagram thereof.

The second embodiment is an example in which phosphor dots of different sizes are arranged as shown in FIG.

In the conventional fluorescent display tube shown in FIGS. 9A and 9B, the difference in luminance between a portion near the filament 4 and a portion far from the filament 4 is 1: 0.8. Assuming 100, 2a is 90% of that and 2c is 11
The area was changed to 0%. As a result, FIG.
As shown in (a) and (b), each phosphor dot 2a, 2
The electron dose per b and 2c became uniform, and the difference in visual luminance could be suppressed.

In the second embodiment, the size of the phosphor dot 2a is 0.3 × 0.27 mm, the size of the phosphor dot 2b is 0.3 × 0.3 mm, and the size of the phosphor dot 2C is 0.3 × 0.3 mm.
By setting the thickness to 0.33 mm, the amount of electrons arriving at each phosphor dot was made uniform, and a fluorescent display tube having uniform luminance was obtained.

[0028]

As described above, according to the present invention, a linear grid is stretched between a filament and a filament, and a voltage for attracting electrons is applied to the linear grid, or a portion far from the filament is applied. By increasing the size of the phosphor dot, it is possible to provide a fluorescent display tube for graphic display with uniform emission luminance and no increase in power consumption.

Further, a linear grid is stretched between the filaments, a voltage for attracting electrons is applied to the linear grid, and the size of the phosphor dots far from the filament is increased. There is an effect that a fluorescent display tube for graphic display having uniform luminance can be provided.

[Brief description of the drawings]

FIG. 1 is a partially cutaway perspective view of a first embodiment of the present invention.

FIG. 2 is a partially enlarged plan view of a phosphor dot portion of FIG. 1;

FIG. 3 is a schematic diagram of an electron beam emitted from a filament according to the first embodiment of the present invention and a current density distribution diagram thereof.

FIG. 4 is a partially enlarged plan view of a phosphor dot portion according to a second embodiment of the present invention.

FIG. 5 is a schematic diagram of an electron beam emitted from a filament according to a second embodiment of the present invention and a current density distribution diagram thereof.

FIG. 6 is a partially cutaway perspective view of an example of a conventional fluorescent display tube for graphic display.

7 is a time chart of an example of a signal for driving the fluorescent display tube for graphic display of FIG. 6;

FIG. 8 is a partially enlarged plan view of a phosphor dot portion of FIG. 6;

FIG. 9 is a schematic diagram of an example of an electron beam emitted from a filament of a conventional fluorescent display tube for graphic display, and a current density distribution diagram thereof.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Anode electrode 2, 2a, 2b, 2c Phosphor dot 3 Grid 4 Filament 5 Linear grid 6 Anode substrate 7 Spacer substrate 8 Cover glass 9 Electron beam G1, G2, G3, G4 Grid electrode An Anode electrode

Claims (3)

(57) [Claims] 1. A phosphor layer arranged in a matrix in a vacuum vessel, a linear grid disposed on both sides of the phosphor layer, and a linear filament disposed in a direction perpendicular to the grid. A fluorescent display tube having the filament at an intermediate position between the filament and the filament.
And the middle height of the grid arranged on both sides of the phosphor layer
A fluorescent display tube , wherein a linear grid is arranged at a position parallel to the filament. 2. A phosphor layer arranged in a matrix in a vacuum vessel, a linear grid disposed on both sides of the phosphor layer, and a linear filament disposed in a direction orthogonal to the grid. The size of the phosphor layers arranged in a matrix increases with distance from the position of the filament, and the size immediately below the filament is smallest. . 3. A phosphor layer arranged in a matrix in a vacuum vessel, a linear grid arranged on both sides of the phosphor layer, and a linear filament arranged in a direction perpendicular to the grid. In the fluorescent display tube having, a linear grid parallel to the filament is arranged between the filament and the filament, and the phosphor layer arranged in a matrix increases as the distance from the filament increases. A fluorescent display tube characterized in that the portion directly below the filament is the smallest.