JPH0676770A - Fluorescent character display tube - Google Patents

Abstract

PURPOSE:To prevent display failure due to movable foreign matters by fitting a magnetic body in a recessed part provided in a positive electrode substrate preliminarily, fixing it to become a trap part, and collecting conductive movable foreign matters. CONSTITUTION:A recessed part 17 is provided on the opposite side of an electrode formed surface of a glass plate in forming a positive electrode substrate 11, a magnetic body 18 is fitted in it, and it is fixed by bonding agent 22 to form a trap part 19. Conductive movable foreign matters generated from an electrode assembly 2 inside a fluorescent character display tube by welding or the like can thus be collected. The foreign matters at a position apart from the trap 19 can be collected easily by applying vibration or the like to the fluorescent character display tube. The recessed part 17 is disposed at a position where no effects are applied to an electron orbit, and the magnetic body 18 is regulated to have such strength as to apply no effects to the electron orbit.

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 flat type fluorescent display tube.

[0002]

2. Description of the Related Art As shown in FIG. 3, the flat type fluorescent display tube which is most widely manufactured at present uses a heat resistant and insulating material such as glass for an anode substrate 1. There is.
Wiring, a base electrode, a phosphor layer, etc. are sequentially laminated and printed on this. The electrode assembly 2 was 42% Ni-6% Cr-remaining Fe.
The grid 3 is made of an alloy (hereinafter referred to as 426) and welded. Further, a plurality of filaments 4 are suspended in parallel with the grid 3 at regular intervals.

A plate glass which is a translucent insulating material is used for the cover glass 5. An exhaust pipe 6 which is a thin pipe for vacuum exhaust is provided in a part of the cover glass 5.

The fluorescent display tube is completed when these parts are hermetically sealed with each other and the inside of the exhaust tube is evacuated.

[0005]

The fluorescent display tube is a kind of vacuum tube and is manufactured in an air-conditioned room in which dust and the like are sufficiently controlled. However, the manufacturing process of the fluorescent display tube is generally long, and foreign substances may remain on the fluorescent display tube. The residual foreign matter in the tube is classified into a conductive substance, an insulating substance, a mobile substance, or a fixed substance, but there is a problem that it obstructs the display of the fluorescent display tube in various forms.

[0006] For example, when an insulating foreign substance adheres to the phosphor layer, display defects such as uneven brightness, a lack of dots in which part of the display is lost, and black dots occur. Further, in the case of a conductive foreign substance, erroneous lighting may occur due to a short circuit between grids, a short circuit between anodes, or the like. The most problematic case is the case of a mobile substance, which moves in the tube, and therefore may or may not be abnormal depending on the attachment site. In some cases, once a product is judged to have no abnormalities, it may become abnormal during use, so countermeasures against mobile foreign substances are the most important issue.

The object of the present invention is to obtain brightness unevenness, missing dots,
An object of the present invention is to provide a fluorescent display tube capable of preventing the occurrence of abnormalities due to a mobile substance without causing display errors such as black spots, short circuit between grids, short circuit between anodes, etc.

[0008]

The present invention is directed to an anode substrate in which wiring, a base electrode and a phosphor layer are sequentially laminated on a plate glass, and a grid is fixed on the anode substrate and further fixed to the grid. In a fluorescent display tube having an electrode assembly in which filaments are suspended at regular intervals, and a cover glass which is sealed to the anode substrate to form a vacuum container,
A recess is provided in a part of the outer surface of the anode substrate, and a magnetic body is fitted and fixed in the recess.

[0009]

Embodiments of the present invention will now be described with reference to the drawings.

FIG. 1 is a sectional view of a first embodiment of the present invention.

The constituent materials and manufacturing process of the first embodiment are the same as those of the conventional fluorescent display tube shown in FIG.

In the first embodiment, as shown in FIG. 1, a commercially available plate glass is used for the anode substrate 11, first, after undergoing steps such as washing, the anode wiring is formed by Ag or the like using the conventional technique. To do. Next, the base electrode and the like of the phosphor layer 13 are formed by printing, and finally, the phosphor layer 13 serving as an anode is printed to complete the anode substrate 11.

Next, the electrode assembly 2 is processed into 4 by etching or the like.
26 alloy or the like is used to manufacture it according to the shape of the anode substrate 11, the grid 3 is adhered to the electrode assembly 2 by welding or the like, and then the filament 4 is suspended. After that, the anode substrate 1
1, the electrode assembly 2 and the cover glass 5 are hermetically sealed as in the conventional case, and an exhaust pipe (not shown) is attached to make the inside a vacuum. Thus, the fluorescent display tube is completed.

In the first embodiment, when the anode substrate 11 is formed, the recess 1 is previously formed on the outer surface of the plate glass opposite to the electrode forming surface.
7, the magnetic material 18 is fitted into the recess 17, and the trap portion 19 is fixed by the adhesive 22.

By forming the trap portion 19, it is possible to capture the conductive mobile foreign matter generated by welding or the like from the electrode assembly 2 in the fluorescent display tube. That is, the moving foreign matter near the trap portion 19 is attracted and captured by the magnetic field. Further, the mobile foreign matter existing at a place away from the trap portion 19 can be easily captured by applying vibration or the like to the fluorescent display tube. In this case, the recess 17 is arranged at a position that does not affect the electron orbit, and the magnetic body 18 is adjusted to have a strength that does not affect the electron orbit.

FIG. 2 is a sectional view of the essential portions of the second embodiment of the present invention.

As shown in FIG. 2, the second embodiment is an example in which the magnetic body 18 is fitted into the exhaust hole 20 and the lid 21 is adhered to fix the magnetic body 18 and to maintain the vacuum. .

In both the first and second embodiments, so-called ferromagnetic material, silicon steel plate, permalloy, ferrite or the like can be used as the magnetic body 18.

[0019]

As described above, the present invention has been a problem in the prior art by trapping the conductive moving foreign matter by the trap portion in which the magnetic body is previously fitted and fixed in the concave portion formed in the anode substrate. It also has the effect of preventing a display failure due to a moving foreign substance. At least, it can be expected to decrease by one digit compared to the conventional display failure occurrence rate.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a first embodiment of the present invention.

FIG. 2 is a sectional view of a main part of a second embodiment of the present invention.

FIG. 3 is a partially cutaway perspective view of an example of a conventional fluorescent display tube.

[Explanation of symbols]

 1, 11 Anode substrate 2 Electrode assembly 3 Grid 4 Filament 5 Cover glass 6 Exhaust pipe 13 Fluorescent material layer 17 Recessed portion 18 Magnetic material 19 Trap portion 20 Exhaust hole 21 Lid

Claims (1)

[Claims] 1. An anode substrate in which wiring, a base electrode and a phosphor layer are sequentially laminated on a plate glass, and a grid is fixed on the anode substrate and a grid is fixed on the grid at a constant interval. In a fluorescent display tube having a suspended electrode assembly and a cover glass that is sealed to the anode substrate to form a vacuum container, a recess is provided in a part of the outer surface of the anode substrate and a magnetic material is inserted into the recess. Fluorescent display tube characterized by being fixed.