JPH0220749Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention is a type of fluorescent display tube in which a light-emitting anode portion is formed on one side of a light-transmitting substrate, and the light emission from the anode portion is observed from the other side of the light-transmitting substrate. In particular, the present invention relates to a fluorescent display tube that has a simplified structure and provides high-quality display without display defects.

In conventional fluorescent display tubes, electrons emitted from a heated filament-shaped cathode are controlled by a control electrode as necessary to selectively strike the anode portion, which has a phosphor layer coated on its top surface. By causing the phosphor layer to emit light, the light emission from the phosphor layer is observed through an envelope for maintaining the control electrode, the cathode, and each of the electrode sections in a high vacuum state. There is.

However, in this conventional type of fluorescent display tube, the control electrode and cathode that exist between the light emitting surface of the phosphor layer and the observer's eyes impede the display, or the display window of the envelope Since the light emitting surface and the light emitting surface are separated from each other, there are problems such as the display looks set back and the viewing angle becomes narrow.

Therefore, the substrate on which the anode portion is formed is made of a light-transmitting insulating material, such as a transparent or semi-transparent glass plate, and one surface of this substrate is made of a transparent material with a phosphor layer coated on the upper surface. A type of fluorescent display tube in which an anode portion made of a conductive film is arranged according to a display pattern and light emission from a phosphor layer is observed through the substrate is being considered.

That is, as the schematic configuration is shown in Fig. 1,
An anode conductor 2 made of a transparent conductive film mainly made of, for example, SnO ₂ or In ₂ O ₃ is attached to a transparent substrate 1, and a display pattern portion on the substrate 1 on which the anode conductor 2 is attached is formed. An insulating layer 3 is deposited on the removed portion. Thereafter, a phosphor layer 4 is deposited on the anode conductor 2 to form an anode part 5, and a control electrode 6 is formed opposite to this anode part 5.
is disposed above the insulating layer 3, and a filament-shaped cathode 7 is stretched above the control electrode 6, and is electrically connected to the respective electrodes on the periphery of the substrate 1. The rear container 10 forming an envelope 9 together with the substrate 1 is sealed with the external terminal 8 passed through the rear panel 1 in an airtight manner, and the interior of the envelope 9 is evacuated to a high vacuum state.

Then, a display signal is selectively applied to the anode section 5 to cause electrons from the cathode 7 to strike the phosphor layer 4, and the light emission from the phosphor layer 4 is transferred to the anode conductor 2 and the transparent substrate 4. It is something that we come to observe through.

In the fluorescent display tube of the type shown in FIG. That is, since the substrate 1 and the light emitting surface are in close contact with each other, the display has the advantage that a large viewing angle can be obtained and an extremely easy-to-read display can be obtained.

Incidentally, the fluorescent display tube is designed to excite the phosphor layer 4 to emit light using a low-speed electron beam accelerated by a low anode voltage of several volts to several tens of volts. It is generally said that only the very surface layer of the phosphor layer 4 excited to emit light by such a slow electron beam emits light.

Therefore, in the type of fluorescent display tube shown in FIG. , absorption of light occurs in each part,
There is a problem that the intensity of the light taken out to the outside decreases, making it impossible to obtain sufficient brightness. It is effective to coat the phosphor layer 4 as thinly as possible, for example, as shown in FIG. It is possible to wear it.

However, in this case, electrons flying from the cathode adhere to the surface of the insulating layer 3 and near the side wall of the opening 3a, as shown in FIG. 2, and the surface of the insulating layer 3 near the anode becomes negatively charged. .

Furthermore, as shown in FIG. 3, there was an embodiment in which a conductive antistatic layer 11 was disposed on the insulating layer 3 by a printing method, but it was arranged so that the antistatic layer 11 and the anode 5 would not be short-circuited. Therefore, the insulating layer 3 tends to be exposed near the opening 3a. In particular, it has been impossible to cover the rising wall portion 3b of the insulating layer 3 in the opening 3a using conventional methods. Therefore, as shown in the figure, electrons adhere to the exposed surface of the insulating layer 3 in the vicinity of the opening 3a, causing it to be negatively charged. Then, as shown by broken lines in FIGS. 2 and 3, the flow of electrons emitted from the cathode 7 is deflected by the negative electric field created by the charged electrons, and the flow of electrons is deflected from the anode portion 5.
A region where electrons do not collide is formed around the phosphor layer 4, causing problems such as shadowing of the light emission of the phosphor layer 4, deterioration of display quality, or, in the case of a thin display pattern, the display becoming difficult to see. It was hot.

The present invention was developed in view of the above-mentioned circumstances, and in a type of fluorescent display tube in which light emission from an anode formed on one side of the substrate is observed from the other side of the substrate, phosphor Focusing on the fact that forming the layer as thin as the thickness of the insulating layer or less is advantageous in terms of increasing the intensity of the light extracted to the outside, the insulating layer is formed in close contact with or close to the insulating layer. , a control electrode made of a conductive thin plate with a window corresponding to the display pattern is provided,
It is an object of the present invention to provide a fluorescent display tube that prevents charging of an insulating layer near a display pattern by using this control electrode, and provides an easy-to-read display without display overlap.

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

FIG. 4 is a vertical sectional view showing a schematic configuration of an embodiment of a fluorescent display tube according to the present invention.

Here, 21 is a substrate made of an insulating material that is transparent to the light emitted by the phosphor, such as transparent glass or semi-transparent glass. An anode conductor 22 made of a transparent conductive film is deposited on one surface of this substrate 21 . The anode conductor 22 is made of, for example, SnO ₂ or
In ₂ O ₃ mixed with a small amount of donor impurity,
Alternatively, a mixture of these may be applied to one entire surface of the substrate 21 by vapor deposition, sputtering, spraying, or
The anode conductor is deposited by a CVD method, and then patterned into the desired anode conductor shape by a photo etching method, a printing mask etching method, or the like. When forming the anode conductor 22, a wiring conductor 23 is simultaneously formed using a transparent conductive film. This wiring conductor 23
The anode conductor 22 is wired according to the driving mode, and the wiring conductor 23 is connected to the terminal portion 24.
It will be derived as follows.

Further, a required portion of one surface of the substrate 21 on which the anode conductor 22 and the wiring conductor 23 are arranged is covered,
Further, an insulating layer 25 made of an insulating material is formed so as to have an opening 25a corresponding to the display pattern. This insulating layer 25 may be colored by mixing a pigment or the like as necessary.

A phosphor layer 26 is formed on the surface of the anode conductor 22 exposed at the bottom of the opening 25a of the insulating layer 25 by electrodeposition, precipitation, printing, or the like. The phosphor layer 26 is formed as thinly as possible so that its upper surface is lower than the upper surface of the insulating layer 25, and within a range that does not cause uneven light emission. An anode portion 27 is formed by this phosphor layer 26 and the anode conductor 22.

Furthermore, a control electrode 28, which is the gist of the present application, is provided in close contact with or in close proximity to the upper surface of the insulating layer 25. In the illustrated example, the insulating layer 2 is
This is the case of the control electrode 28 tightly fixed on the top of the control electrode 5.

This control electrode 28 is made of a conductive thin plate,
A transparent window 28a having a shape corresponding to the display pattern is provided in a portion facing the phosphor layer 26. The window portion 28a of the control electrode 28 is located at the same position as the wall surface 25b of the opening 25a of the insulating layer 25, that is, in the same shape as each segment on which the phosphor layer 26 is attached, or as shown in FIG. As shown in FIG.
It extends inward from the wall surface 25b of a. In a normal display pattern, this extending length is preferably in the range of 0 to 1.0 mm from the wall surface 25b on one side.
Preferably, it is formed to extend by 0.1 to 0.3 mm, as this is very effective.

Further, the control electrode 28 does not need to cover the entire upper surface of the insulating layer 25, and the control electrode 28 does not need to cover the entire upper surface of the insulating layer 25.
It is only necessary to remove the electrons that are charged in the vicinity of the opening 25a, and it is sufficient to dispose it in the vicinity of the opening 25a. Therefore, as shown in FIG. 5, the control electrode 28 has a through hole 2 in a part unrelated to display, in addition to a window part 28a in the part facing the phosphor layer 26.
8b is effective in reducing grid current.

Further, when the width of the light emitting pattern is wide, a more uniform display can be obtained by forming the window portion of the control electrode in a mesh shape or by pasting a mesh on the window portion.

Furthermore, in FIG. 4, 29 is a filament-shaped cathode, and 30 is sealed to the peripheral part of the substrate 21 to form an envelope together with the substrate 21, and the above-mentioned electrode parts are maintained in a high vacuum atmosphere. It is a container on the back.

According to the structure shown in FIG. 6, the control electrode 28 extends to the upper surface of the insulating layer 25 surrounding the anode portion 27 and above the phosphor layer 26 inside the wall portion 25b of the insulating layer 25. is arranged to protrude, so that charging of electrons on the upper surface of the insulating layer 25 and the wall portion 25b is prevented.

Therefore, there is no fear that the electrons emitted from the cathode 29 will be polarized by the negative electric field formed by the charging, and the electrons will uniformly strike the entire surface of the phosphor layer 26 of the anode section 27. Since the entire surface of the phosphor layer 26 emits light, the anode portion 27 can emit uniform light.

In addition, the present invention is not limited to the embodiments described above and shown in the drawings, but can be implemented with various modifications without changing the gist thereof.

As described above, the fluorescent display tube according to the present invention is a type of fluorescent display tube in which light emission from an anode portion formed on one side of a substrate made of a transparent insulating material is observed through the substrate. In this step, a phosphor layer is deposited sufficiently thinly on the anode conductor exposed in the opening for an insulating layer that has an opening corresponding to the display pattern shape and covers a transparent conductive film that becomes an anode conductor, and The control electrode is disposed on the insulating layer in close contact with or in close proximity to the insulating layer, including at least the inside of the opening formed by the insulating layer.

Therefore, in the fluorescent display tube according to the present invention, the control electrode section prevents charging on the surface of the insulating layer near the anode section, and electrons emitted from the cathode uniformly impinge on the entire surface of the phosphor layer. It became like this,
It has the excellent feature of providing uniform light emission over the entire surface of the anode section and providing an extremely high-quality display with no display gaps, and its effects are extremely large.

In addition, in the fluorescent display tube according to the present invention, if the control electrode is configured to be in close contact with the insulating layer, there is no need for a mesh-shaped control electrode or a spacer member for attaching it. It has features such as greatly simplifying the work,
The effect obtained in terms of reducing manufacturing costs is extremely large.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram showing an example of a conventional fluorescent display tube, FIGS. 2 and 3 are diagrams for explaining problems in conventional fluorescent display tubes, and FIG. 4 is a diagram showing the structure of a conventional fluorescent display tube. FIG. 5 is a partial plan view of a fluorescent display tube control electrode plate according to the present invention, and FIG. 6 is an enlarged configuration diagram of main parts of a fluorescent display tube according to the present invention. It is. DESCRIPTION OF SYMBOLS 21... Substrate, 22... Anode conductor, 25... Insulating layer, 25a... Opening of insulating layer, 25b... Wall of insulating layer, 26... Phosphor layer, 27... Anode part, 28... ...Control electrode, 28a...Window part, 29...
…cathode.

Claims (1)

[Claims for Utility Model Registration] (1) An anode conductor is formed using a transparent conductive film on one side of a substrate made of a translucent insulating material, and light is emitted by the bombardment of electrons from the cathode onto the anode conductor. In a fluorescent display tube in which a phosphor layer is deposited and the light emission of the phosphor layer is observed from the other side of the substrate, the anode conductor is deposited with an opening corresponding to a display pattern. an insulating layer; a phosphor layer deposited on the anode conductor exposed from the opening of the insulating layer to a thickness not exceeding the thickness of the insulating layer; and a phosphor layer disposed on the insulating layer. and a control electrode made of a conductive thin plate in which a window portion corresponding to the display pattern is formed at least in a portion facing the phosphor layer. (2) The fluorescent display tube according to claim 1, wherein the window portion of the control electrode extends from 0 to 1.0 mm inside the wall surface of the opening of the insulating layer.