JPH0744019B2 - Flat emission fluorescent display tube - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a fluorescent display tube, and more particularly to improvement of the structure of an anode substrate of a flat emission fluorescent display tube.

[Conventional technology]

A so-called flat-emission fluorescent display tube for observing a display through a glass substrate from the anode substrate side has been widely used mainly in the audio and VTR markets for the purpose of enlarging the viewing angle and improving the display quality. Conventionally, the sectional structure of this type of flat-emission fluorescent display tube is as shown in FIG. An opening 22 is formed on the glass substrate 21 with an aluminum thin film layer. The opening is formed in a display pattern shape, and a stripe-shaped or mesh-shaped thin line pattern 23 is formed inside the opening so as not to hinder the visual field. A peripheral pattern 24 is also formed of an aluminum thin film layer so as to surround the opening. A phosphor layer 25 is formed by coating on the aluminum thin film layer, and this layer has a shape that covers all of the openings of the aluminum thin film layer and a part of the peripheral portion. Although not shown in the figure, both the opening and the peripheral pattern are connected to the external electrode by the extraction electrode, and the anode potential is applied. As the phosphor, zinc oxide or a zinc sulfide-based phosphor having sufficient emission brightness even with a low-speed electron beam is generally used. An insulating layer 26 made of low melting point glass is formed by coating around the phosphor layer so as to surround the phosphor layer. The insulating layer 26 contains a black pigment for the purpose of preventing light leakage. An anode substrate is constructed by sequentially forming the above layers. The anode substrate and the cover glass 27 form a vacuum container. A filament cathode 28 of a thermoelectron source and a grid electrode 29 for electron beam acceleration control are installed in this container.

[Problems to be solved by the invention]

In the above-described conventional flat-emission fluorescent display tube, the difference in the distance from the cathode or the difference in the wiring resistance easily causes a difference in brightness, that is, so-called uneven brightness, in the same display pattern, and the display quality is remarkably deteriorated. In the example of FIG. 3, the right side of the opening, which is the display pattern, that is, the vicinity of the boundary with the peripheral pattern is far from the cathode, and the electron dose flying from the cathode is smaller than that of the center and left side of the opening, resulting in low brightness. For this reason, the inside of the opening does not have uniform brightness, and uneven brightness occurs. Since there are various restrictions on the number of cathodes to be installed and the installation location, it is difficult to obtain a uniform electron beam density.

[Means for solving problems]

In contrast to the above-described conventional flat-emission fluorescent display tube, the present invention makes the phosphor layer shape on the peripheral pattern formed of the aluminum thin film layer into a stripe shape or a mosaic shape, and forms a part of the aluminum thin film layer of the peripheral pattern. The density of the electron beam that is exposed and controlled in the peripheral pattern and the opening is controlled to significantly reduce the uneven brightness.

[Action]

The flat-emission fluorescent display of the present invention has a phosphor layer having a stripe shape or a mosaic shape on the peripheral pattern formed of the aluminum thin film layer. In the layered structure of the aluminum thin film layer and the phosphor layer having such a shape, a part of the aluminum thin film layer is exposed, so that the phosphor layer is entirely covered with the peripheral pattern, compared to the conventional layered structure. The current easily flows as much as there is no resistance of the phosphor layer, and the effect of increasing the density of electron beams flowing in the peripheral pattern is exhibited. As a result, the density of electron beams flowing into the edge of the opening near the boundary with the peripheral pattern also increases, so that the brightness at the edge of the opening increases and uneven brightness within the opening is suppressed. Therefore, if this stripe-shaped or mosaic-shaped phosphor layer is formed on the peripheral pattern that is close to the portion where the brightness becomes low due to the uneven brightness generated in the conventional structure, the peripheral effect is achieved by the above action. The electron beam density flowing in the partial pattern is increased, the brightness at the end of the opening near the peripheral pattern is improved, and the uneven brightness at the opening is significantly reduced.
Further, by appropriately selecting the area ratio between the phosphor-covered portion of the peripheral pattern and the exposed portion of the aluminum thin film, or by partially changing this area ratio, the anode electric field distribution is controlled and the electron beam density is made appropriate. Is possible.

[Embodiment 1] FIG. 1 is a sectional view of Embodiment 1 of the present invention. On a glass substrate 1, an opening 2 which forms a display pattern with an aluminum thin film layer, and a peripheral pattern 3 which surrounds the opening 2 are formed. A fine line pattern 4 is formed in a stripe shape, a ladder shape, or a mesh shape in the opening so as not to cause any visual trouble. The phosphor layer 5 is formed by coating so as to cover each part formed of these aluminum thin films, but all of the openings and the peripheral pattern on the left side in the figure are continuously covered with the phosphor. The phosphor layer on the right peripheral pattern is a stripe-shaped phosphor layer 6. That is, the peripheral pattern of this portion is composed of a portion covered with the phosphor layer and a portion where the aluminum thin film layer is exposed as it is. Further, an insulating layer 7 made of low melting point glass is formed so as to surround the phosphor layer. The anode substrate having the structure described above forms a vacuum container together with the cover glass 8, and in this container a filament cathode 9 of an electron beam source and a grid electrode 10 for accelerating and controlling the electron beam.
Is installed.

[Embodiment 2] FIG. 2 is a side view of Embodiment 2 of the present invention. In the figure, only the anode substrate is shown, and the cover glass, cathode and grid electrode are omitted. The pattern of the aluminum thin film layer formed on the glass substrate 1 is the same as that of the first embodiment, but the phosphor layer 6 is formed in stripes on the peripheral pattern 3.
And insulating layers 11 are alternately formed. In such a layered structure, the electric field is not concentrated as compared with the structure in which the peripheral pattern is covered only by the phosphor layer, the irradiation amount of the electron beam to the opening is increased, and the uneven brightness is realized.

〔The invention's effect〕

As described above, the present invention controls the distribution of electron beams emitted from the cathode by forming the phosphor layer on the peripheral portion pattern of the aluminum thin film into a stripe shape or a mosaic shape in the flat emission fluorescent display tube. Further, there is an effect that the uneven brightness is remarkably reduced and a good display state is realized.

[Brief description of drawings]

FIG. 1 is a sectional view of a first embodiment of a flat-emission fluorescent display tube of the present invention, FIG. 2 is a sectional view of an anode substrate of a second embodiment of the flat-emission display tube of the present invention, and FIG. FIG. 6 is a cross-sectional view of a conventional flat-emission fluorescent display tube. 1,21 ...... Glass substrate, 2,22 ...... Aperture, 3,24 ...... Peripheral pattern, 4,23 ...... Thin line pattern, 5,25 …… Phosphor layer,
6: Striped phosphor, 7,26 ... Insulating layer, 8,27.
Cover glass, 9,28 …… Cathode, 10,29 …… Grid electrode, 11 …… Striped insulating layer.

Claims (1)

[Claims] 1. An aluminum thin film layer having a display pattern-shaped opening and a peripheral pattern surrounding the opening on a glass substrate, and a shape that covers at least all the openings and a part of the peripheral pattern. A phosphor layer of
A vacuum container is constituted by a cover glass and an anode substrate on which an insulating layer made of low melting point glass surrounding the phosphor layer is sequentially formed, and a filament cathode and a grid electrode for electron beam acceleration and control. In a flat-emission fluorescent display tube in which the phosphor layer on the peripheral portion pattern made of the aluminum thin film layer has a stripe shape or a mosaic shape, tube.