JPS61176036A - Fluorescent character display tube - Google Patents

Abstract

PURPOSE:To improve the reliability of a fluorescent character display tube and prolong its life span by comprising a thermionic emission section with an aerial structure, heating only the section at high temperatures, comprising a metallic film with a laminated structure, improving its mechanical strength, and preventing the disconnection of the metallic film. CONSTITUTION:A metallic film with a laminated structure consisting of a lower layer metallic film 3, an intermediate layer metallic film 4, and an upper metallic film 5 is formed on an insulating substrate 1 arranged in a vacuum container though an insulating layer 2 and a thermionic emission section 6 and a cathode conductor 7 are formed. The length and width of this electron emission section 6 are set to preset values and its resistance value is set to a desired value. A gap 8 is provided at the lower part and the electron emission section 6 is comprised with an aerial structure, then the electron emission section 6 is coated with electron emission material 10. The lower and upper layer films 3 and 5 of this metal laminated film use tungusten or a tungusten alloy and the intermediate film 4 uses a kind of tantalm, titanium, a nichrome alloy, and a nickel alloy. In addition, the mechanical strength of the metallic film is improved and the disconnection of the metallic film is prevented by heating only the electron emission section 6 at high temperature.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a dot matrix display or image display type fluorescent display tube, and particularly to the structure of the thermionic cathode thereof.

[Conventional technology]

Conventionally, this type of fluorescent display f has a structure shown in FIG. FIG. 5 is a sectional view of a conventional fluorescent display tube. An anode 22 coated with a fluorescent substance is disposed on a substrate 21 . A mesh-like grid 234 is arranged above the anode 22, and a filament-like cathode 24t is welded to a metal support 25, 26 and stretched above the grid 23, and a cover glass 27 and A side plate 28 is attached to maintain a vacuum inside the tube, making it a fluorescent display tube. The operation of this fluorescent display tube is based on the filament-like cathode 24.
By assembling a matrix with the anode 22 and the grid 23 while constantly heating the anode 22 and applying a positive voltage to the grid 23 that intersects with the anode 22 to emit light, the electrons emitted from the cathode 24 are transferred to the grid 24 and the anode 22. Generally, the light is selectively selected and incident on the phosphor on the anode 22 to produce a light-emitting display.

In conventional fluorescent display tubes, the cathode is constantly heated by electricity, which has poor energy efficiency, and the triode structure has a grid between the cathode and anode, so as the number of dots on the anode increases, As the spacing becomes smaller, it is extremely difficult to match the light transmission of each grid to the dots, and it is also difficult to form pressure-resistant columns at important points inside the vacuum container, making it difficult to increase the size or thinner structure. It is extremely disadvantageous for development.

In order to eliminate the disadvantages of the past, for example,
2862, a planar thermionic source has been proposed. As shown in the plan view and lfr plane view of FIG. 6, this is done by forming the conductive thin film 32 on the insulating substrate 31 in an uneven shape, and by making the cross-sectional area of the recesses smaller than that of the convex parts, so that the recesses overlap the convex parts. It has a structure in which the shape is released to increase the electrical resistance, and an electron-emitting substance 33 is attached to the concave portion.

[Problem that the invention seeks to solve]

However, the operation of a planar electron source with such a structure is to heat the F recess by passing a current through the conductive thin film and emit thermionic electrons, but since the recess is also in contact with the substrate, It takes time for the cathode to heat up because it absorbs heat from it, and on the other hand, if you turn off the electric current to stop thermionic emission, it takes time for the heat to dissipate from the recess because the substrate is heated, and the cathode It is difficult to turn on and off sharply.

The present invention has been made to solve the above problems, and in a diode tube with a simple structure, dots are formed at high density, the display area is relatively large, the entire display device is formed thinly, and the cathode is It is an object of the present invention to provide a fluorescent display f for a dot matrix display which can rapidly heat and dissipate heat, and can selectively emit light when the cathode is turned off.

[Means to solve all problems]

The cathode of the fluorescent display tube of the present invention has a hollow structure in which a metal film is formed on a substrate, and a part of the lower substrate corresponding to the thermionic emission part of the metal layer is removed to form a gap. , and has a planar cathode structure in which the mechanical strength of the floating thermionic emission part is improved by using a laminated metal layer structure, and the thermionic emission part is further coated with a thermionic emission material.

That is, the gist of the present invention is to make the thermionic emission part a virtual structure, so that only that part can be heated to a high temperature, and steep heating and heat radiation can be made possible. ! The laminated structure has a mechanical strength t-1, which can withstand the thermal shock of the metal layer caused by repeated current interruptions in the thermionic emission part, stress caused by the difference in thermal expansion between the metal layer and the substrate, etc. The purpose is to prevent disconnection of the metal film by holding the metal film, thereby increasing reliability and making it possible to extend the life of the metal film.

〔Example〕

Hereinafter, the I-man according to the present invention will be explained in detail with reference to the embodiments shown in the drawings.

FIG. 1 (aL (b) rx is a plan view and cross-sectional view showing the structure of the cathode substrate of the fluorescent display tube according to the present invention, and FIGS. 2 (a) to (g) are the fluorescent display tube according to the present invention. FIG. 3 is a cross-sectional view showing the manufacturing process of the cathode substrate of the display tube, FIG. 3 is a cross-sectional view of the fluorescent display tube according to the present invention, and FIG. 4 explains the operation of the fluorescent display tube according to the present invention. FIG.

An embodiment of the present invention will be described with reference to FIG.

Reference numeral 1 designates an insulating substrate, on which an insulating layer 2 made of a material such as frit glass whose main component is lead glass is formed by a full printing method or the like. Then on top of that is a lower metal film 3 consisting of tungsten alloy = 9, for example several thousand, followed by titanium, tantalum and chromium.

A middle layer metal film 4 of at least one type of nickel, nichrome alloy, etc. is deposited to a thickness of about several micrometers, followed by an upper layer metal film 5 of tungsten or a tungsten alloy of approximately several thousand amps. A cathode conductor 7 is formed. Each thermionic emission part is designed to have a desired resistance value, for example, a width of about 10 μm.

The shape is set to a length t of several hundred μm4. Furthermore, a gap 8 is provided at the bottom of each thermionic emission part 6, and a thermionic emission material 10 such as (Ha, Sr, Ca)Q is provided in the valley thermionic emission part 6.
(not shown) is attached. In addition, a cathode terminal 9 is made of silver paste for electrical connection with the outside. Note that it is also possible to use the cathode conductor 4 as it is for the cathode terminal 9.

In this case, the lower metal film 3 and the upper metal film 5 are made of a tungsten casing and a tungsten alloy is used as the thermionic emitting material 10.
This is to make the intermediate layer metal film 5 maintain its mechanical strength.

Next, a method of manufacturing a fluorescent display tube having a circular cathode according to the above embodiment will be explained with reference to FIGS. 42 and 3. 29 shown in FIG. 2, an insulating layer 2 is prepared by depositing frit glass containing lead glass on an insulating substrate 1 such as glass by a printing method, and a laminated board is prepared. A 0-order (
The photosensitive resin 11f:fi cloth of step b) was applied, and exposed and developed to obtain the result of step (C). Subsequently, the entire metal laminated film (dl) is etched in the order of tungsten-titanium-tungsten alloy to form the thermionic emission region 6 and cathode conductor 7 (not shown), and the photosensitive resin 11 is removed. As shown in (e), photosensitive resin 11 is again coated, exposed, developed, buttered, and the insulation 112 is etched with t-perchloric acid, etc.) to complete the entire gap 8. In normal solution etching, the lateral direction is etched to the same degree as the depth direction, so if the width area of the thermionic emission part 60 is etched deeply, a structure having a gap 8t below the thermionic emission part 6 can be obtained. Next, the photosensitive resin 11 is removed, and a thermionic emission material 10 such as (Ba, Sr, Ca) CO3 is formed on the thermionic emission region 6 by electrodeposition, etc., to obtain a cathode substrate in the process (g). Here, in FIG. 2, the lower part of the thermionic emission section 6 is structured to have a gap 8t'' for each electron emission section, but in the structure shown in FIG. Any structure is possible.

Next, a translucent insulating substrate 12 made of glass or the like shown in FIG.
A conductive thin film of indium oxide, aluminum, etc. is deposited thereon by a spraying method, a CVD method, a sputtering method, etc., and a normal photoetching process is performed to form a =9 anode body 13. An anode insulator Jt114 that becomes a zero-order partition wall. The phosphor layer 15 is formed on the anode conductor 13 by a printing method or the like.
is formed, and further formed by a printing method or the like on the seal glass 16' to form an anode substrate.

Next, the cathode substrate on which the thermionic emission material 10 is disposed and the anode substrate on which the phosphor/ill 5i is disposed are combined in the step 5 where the thermionic emission material 10 and the phosphor layer 15 face each other to form an envelope. Then, install the exhaust pipe 17. Here, the anode insulating layer 14 serves as a substitute for the thermionic emission material 10.
and the phosphor N115 are kept uniform. Next, exhaust pipe 17
While evacuating the inside of the tube E9, the thermionic emitting substance 10 (Ba
, Sr, Ca) co, '1 by heating with electricity (Ha, S
r, Ca)O to form a thermionic cathode, the tube was sealed, and the inside of the tube was maintained at a high vacuum. A fluorescent display tube was used.

Next, the operation of the fluorescent display tube of the present invention will be explained using FIG. When an L rebulse current is applied to the cathode conductors 7a and 7b using an external device (not shown), the temperature of the thermionic emitting material 10a between the cathode conductors 7a and 7b rapidly rises to around 600°C, and thermionic electrons are emitted. The emitted thermionic electrons cause the thermionic emission material 10a and the anode conductor 131, 13...
The phosphor layer 15nJ depending on the signal applied to...
Reach C and make the phosphor 1ii 15ft emit light. Next, when the pulse current applied to the cathode conductors 7a and 7b is cut off, the temperature of the thermionic emission substance 10a decreases and thermionic emission rapidly stops. In this way, a pulsed current is sequentially applied to the external device to the cathode conductors 7b and 7c, 7c and 7d...
An image can be displayed on the phosphor layer by flowing...

〔Effect of the invention〕

As described above, the fluorescent display tube according to the present invention has a simple structure because it has a diode structure without a grid, consisting only of an anode substrate on which a phosphor NI is disposed and a cathode substrate on which a thermionic emission substance is disposed. This has the effect of easily making the display device thinner and lighter.

Furthermore, by making the thermionic emission section a virtual structure, it is possible to heat up and dissipate heat rapidly, shorten the response time of the cathode, and obtain sufficient brightness, resulting in a clear display with no leakage of light.
t can be obtained. Furthermore, by forming the cathode in a laminated structure, the mechanical strength is improved, and disconnection of the metal layer due to interruption of current can be prevented, resulting in high M reliability and a long service life.

[Brief explanation of the drawing]

FIGS. 1(a) and 1(b) are a plan view and a cross-sectional view showing the structure of a cathode substrate of an embodiment of a fluorescent display tube according to the present invention;
2 fa1 to (g) are schematic cross-sectional views showing the manufacturing process of the cathode substrate of another embodiment of the fluorescent display tube according to the present invention, and FIG. 3 is a cross-sectional view of one embodiment of the fluorescent display tube according to the present invention. , 4th
The figure is a schematic plan view showing the operation of a fluorescent display tube according to the present invention;
Fig. 5 is a sectional view of a conventional fluorescent display tube, Fig. 6(a),
(b) is a plan view and cross-sectional view of a conventional flat cathode. l...Insulating substrate, 2...Insulating layer, 3.
... Lower layer metal film, 5 ... Upper layer metal film, 6
...Thermionic emission part, 7... Cathode conductor,
8... Gap, 9... Cathode terminal, 10.
...Thermionic emission/dentin, 11... Photosensitive resin, 12... Transparent insulating substrate, 13...
...Anode conductor, 14...Anode insulating layer, 15...
...phosphor layer, 16... seal glass,
17...Exhaust pipe, 21...Insulating board,
22... Phosphor layer, 23... Grid, 24... Filament, 25.26...
... Metal support, 27 ... Cover glass, 2
8...Side plate, 31...Insulating board, 3
2... Conductive thin film, 33... Electron emitting substance. Kaya 11! I C0L) $2I! I Kaya 5 Kuniyo Otsu Hard

Claims (2)

[Claims] (1) A plurality of thermionic cathodes disposed on an insulating substrate and a phosphor layer disposed on a translucent insulating substrate are placed in a vacuum container, with each thermionic cathode and phosphor layer disposed on an insulating substrate. In a fluorescent display tube having a structure in which the thermionic cathodes are arranged facing each other and spaced apart from each other in a direction crossing each other, the thermionic cathode forms at least three layers of metal laminated films on an insulating substrate, and A structure characterized in that at least a part of the insulating substrate corresponding to the emission part is removed, a gap is provided below the thermionic emission part, and a thermionic emission material is coated on the thermionic emission part. light display tube. (2) The lower and upper metal layers of the metal laminated film are made of tungsten or a tungsten alloy, and the middle metal film is made of at least one of tantalum, titanium, nichrome alloy, and nickel. 1
) Fluorescent display tube as described in item ).