JPS62177840A - Tipless fluorescent character display tube - Google Patents

Abstract

PURPOSE:To make it possible to absorb and remove a released gaseous component produced from a sealing material when it is sealed, by furnishing a shielding member with a shield opposing to the exhaust port of an envelope. CONSTITUTION:In a plain plate 10, an exhaust port 13 is bored to exhaust the gas in an envelope G. Inside the exhaust port 13, a shield member 14 is furnished a little apart from the plate 10, and the shield member 14 consists of a shield 14a of a metal plate furnished apart from the plate 10 and a support 14b to fix the shield 14a, and the support 14b is contacted and fixed to the plate 10 which is a part of the envelope G. The shield 14a has a width enough to absorb and remove sufficiently the component of the sealing material 16 when it comes straight to contact to the shield 14a.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides a method for creating a vacuum state inside the envelope by sealing an exhaust hole provided in the envelope with a lid member in a vacuum chamber. A chip without an exhaust pipe that prevents the components of the sealing material that adheres the lid member to the envelope from entering the envelope, especially during sealing. This relates to a fluorescent display tube.

[Prior art]

In general, a fluorescent display tube consists of a filament-shaped cathode that emits electrons, a control electrode that accelerates the emitted electrons and controls the flow of electrons, and a phosphor that emits light when the electrons that have passed through the control electrode collide with each other. It consists of an anode consisting of a layer and an anode conductor that applies an anode voltage to the phosphor layer, and has the same structure as a vacuum tube. Therefore, the electrodes and the like are placed in an envelope kept in vacuum.

The envelope is formed into a flat box shape, with a substrate on which the anode is disposed, and a flat plate facing the substrate with a side plate interposed therebetween. An exhaust hole was bored in a part of the envelope, and an exhaust pipe (also called a tipless pipe) made of a glass tube was implanted in the exhaust hole. Then, the gas inside the envelope is suctioned and exhausted from the exhaust pipe, and the inside of the envelope is 1×10-5 to I×10.
'When the vacuum reached a high level of Torr, the exhaust pipe was melted and sealed.

However, since the exhaust pipe protrudes from the envelope, it not only has a negative space factor when mounting a fluorescent display tube, but also has the problem of poor impact resistance because the exhaust pipe is made of glass. Was.

Therefore, the present applicant eliminated the exhaust pipe (chip pipe) and closed the exhaust hole made in the envelope with a flat lid member through a sealing material made of oxide solder glass. An application for a fluorescent display tube with an enclosure has been filed and published. (Utility Model Application No. 60-12256) This is called a chipless fluorescent display tube. The following is a conventional example of this chipless fluorescent display tube.
A detailed description will be given with reference to the drawings shown in the figures.

In the figure, reference numeral 101 denotes a substrate that requires insulation and translucency, and a glass plate is generally used as the substrate. On this substrate 101, anode conductors 102 arranged in stripes are formed using a thin film.

Furthermore, an insulating layer 103 is disposed on the substrate 101 by a thick film printing method, and shields the electrodes and the like inside the envelope 100.

A phosphor layer 104 is disposed on the anode conductor 102, and together they constitute an anode A.

Above the anode A, there are ficimene 1 to 1 that emit electrons.
A shaped cathode 105 and a control electrode 106 for accelerating electrons and controlling the flow are provided.

In the envelope, the substrate 101 and a flat plate 107 facing the substrate 101 are assembled with a sealing material 111 via a west side plate 108 provided at the periphery of the substrate 101. In this embodiment, an exhaust hole 107a is formed in a flat plate 107 in a part of the envelope. On the outer surface of the exhaust hole 107a, a flat lid member 110 is provided with a sealing material 10 made of oxide solder glass whose main component is low melting point frit glass.
It is fixedly sealed by 9.

The process of bonding the envelope 100 with the sealing material 11 and assembling it into a flat box shape in this way is called a sealing process.

After the gas in the sealed envelope is exhausted through the exhaust hole 107a, only the lid member 110 is heated, the sealing material 109 is melted, and pressure is applied from above to press the lid member 110 to the flat plate 107. The lid member 110 is fixed to the flat plate 107 by cooling it in this state. This process of fixing the lid member 110 is called a sealing process.

[Problem that the invention seeks to solve]

Sealing material 109 attached to lid member 110 in the sealing step
If the amount is too small, it will not be completely sealed, causing leakage, and if it is too large, it will flow into the exhaust hole 107a as shown. Furthermore, even if the amount is adequate, the exhaust hole 107
A very small amount of sealing material 109 appears in the space connected to a, and this sealing material 109 is heated during the sealing process and becomes molten. Further, since the interior of the envelope 100 is in a high vacuum state, the components of the sealing material 109 become gas molecules and scatter. The development in which gas molecules released when the sealing material 109 is melted scatters into the envelope 100 is performed in a Pelger maintained in a high vacuum. It travels straight, but if there is an obstruction along the way, it will be adsorbed to or re-emitted from the surface of the object depending on the energy of the interaction between the incident molecule and the surface of the object.

Therefore, the released gas is transmitted to the cathode in the envelope 100,
It has the possibility of adhering to control electrodes, anodes, etc.

Conventional fluorescent display tubes have been designed to minimize the amount of gas emitted from the sealing material by controlling the application position and amount of the sealing material 9, the diameter of the exhaust hole 7a, etc. I couldn't do it. In addition, it is not easy to manufacture the fluorescent display tubes under the same conditions due to the accuracy of parts and work methods, and in some cases, emitted gas may flow into the envelope, resulting in a highly active filament cathode. Some of them adhere to the surface and deteriorate the emission characteristics 1, which has a large effect on the dispersion of display tube characteristics and has problems such as hindering the improvement of productivity.

[Purpose of the invention]

In order to solve the above-mentioned problems, the present invention provides a shielding member near the exhaust hole in the envelope so that the gas emitted from the sealing material is adsorbed and removed by the shielding member. The object of the present invention is to provide a chipless fluorescent display tube that eliminates contamination that adheres to electrodes, etc., and that consistently provides stable emission characteristics.

[Structure of the invention]

In order to achieve the above object, the present invention provides a chipless fluorescent display tube in which an exhaust hole formed in a part of the envelope of the fluorescent display tube is sealed with a flat lid member via a sealing material. The device is characterized in that a shielding member having a shielding portion is provided in the vicinity of the exhaust hole in the envelope and at least at a position facing the exhaust hole. Further, it is preferable that the shielding member is provided facing the exhaust hole and has an area capable of shielding the gas emitted from the sealing material from going straight.

Furthermore, it is more preferable that the shielding member be formed of a support member that supports the filamentary cathode, from the viewpoint of making the display area within the display tube as large as possible.

Furthermore, it is more preferable in terms of removal of harmful gases that the shielding member is composed of a flat plate member facing the exhaust gas pores and a cylindrical part provided in the outer circumferential direction of the flat plate member.

〔Example〕

The present invention will be described in detail below with reference to embodiments shown in the drawings.

In general, a fluorescent display tube is a display tube in which an anode consisting of a phosphor layer and an anode conductor is formed on a substrate, and the anode is bombarded with electrons from a filament-shaped cathode to display light emission. A type in which the luminescent display of the phosphor layer is observed from the side of the substrate opposite to the phosphor layer through the substrate is called a front-emitting fluorescent display tube. The type in which the display is observed through a flat plate facing the substrate is called a conventional fluorescent display tube.

Embodiment 1 The embodiment shown in FIGS. 1 and 2 is an example of a front-emission type chipless fluorescent display tube.

FIG. 1 is a sectional view of a chipless fluorescent display tube of the present invention, and FIG. 2 is an enlarged sectional view of the main part of FIG. 1.

Reference numeral 1 in the figure is a substrate, which requires insulating properties and translucency since the display is observed through the substrate 1.

Generally, a glass plate is used as the substrate 1. This board 1
A striped anode conductor 3 and a wiring conductor 4 made of an M thin film are patterned on the inner surface with an antireflection layer 2 interposed therebetween by means of vacuum evaporation or photolithography. Therefore, because of the anti-reflection M2, the mirror surfaces of the striped anode conductor 3 and the wiring conductor 4 made of AQ thin film cannot be seen through the substrate 1.

Next, a colored insulating layer 5 is provided on a portion of the patterned substrate 1 other than the display pattern by screen printing. This insulating layer 5 has the function of shielding the control electrode 6 and filament-shaped cathode 7 disposed inside the envelope G, and also has the function of providing a black background to improve contrast and visibility.

A phosphor layer 8 is provided on the striped anode conductor 3. The anode conductor 3 and the phosphor layer 8 constitute an anode A.

A mesh-like control electrode 6 is disposed facing the anode A, and a filament-like cathode 7 is further spaced apart and fixed to support members 9 provided at both ends of the envelope G and stretched. There is.

This filamentary cathode 7 has oxides of alkaline earth metals Ca, Sr, and Ba attached in the form of a solid solution to the surface of a thin tungsten wire. Since this oxide filament is very active, when components of the sealing material etc. adhere to the surface of the cathode 7, the surface of the cathode reacts with the deposited components, and the excess gold @Ba, which is a thermionic emission source, is mixed with other compounds. It is known that the electron emission characteristics deteriorate as a result of the change.

Next, a plane plate 10 is placed facing the substrate 1 with a side plate 11 interposed therebetween. Substrate 1, side plate 11 and flat plate 1
A sealing material 121 mainly composed of low melting point frit glass is applied to each bonding surface of the 0, and the 0 is assembled into a flat box shape in a sealed state.

Further, the flat plate 10 is provided with an exhaust hole 13 for exhausting the gas inside the envelope G. Inside this exhaust hole 13, a shielding member 14 is arranged somewhat in front of the flat plate 10. The shielding member 14 includes a shielding portion 14a provided at a position where the metal plate is spaced apart from the flat plate 10, as shown in FIG.
It is comprised of a support part 14b for fixing this shielding part 14a. The support portion 14b is adhesively fixed to the flat plate 10, which is a part of the envelope G. The shielding part 14a is
It is necessary to have a width that allows components of the sealing material 16, which will be described later, to come into contact and be sufficiently adsorbed and removed when they move straight. That is, in FIG. 2, the arrows indicate the traveling trajectory of the component of the sealing material 16 when it moves straight and enters into the envelope G. In particular, the arrow indicates the case where the trajectory is the widest. It is necessary to form the shielding part 14a as large as the point where this arrow and the shielding part intersect. Further, the distance between the shielding part 14a and the plane plate 10 is
The side surface area of the virtual columnar body having the upper surface as the top surface and the surface of the flat plate 10 as the bottom surface is larger than the area of the exhaust hole 13, so that a large conductance can be obtained when exhausting air.

A flat lid member 15 is bonded and fixed to the outside of the exhaust hole 13 via a sealing material 16 made of oxide solder glass, as in the conventional case. The sealing material 16 applied to the lid member 15 is printed in a required amount in a ring shape so that it does not flow into the exhaust hole 13.

The lid member 13 to which this sealing material is attached may be pre-sintered in a vacuum to remove the solvent and gas contained therein, thereby reducing the generation of gas during sealing. When this lid member 15 is set near the exhaust hole and put into the Pel jar, and the envelope G is sealed in the Pel jar and the inside of the Pel jar is evacuated to a vacuum state, the gas inside the envelope G is also removed from the exhaust hole 1. It is further evacuated and becomes a vacuum state. When the desired vacuum state is achieved, the lid member 15 is locally heated to melt the sealing material 16, and while being pressed against the flat plate 10, the heating of the local heating device is stopped and the lid member is cooled. 15 is fixed to the flat plate 10. At this time, there is a possibility that component molecules of the sealing material 16 may scatter and enter into the envelope. At this time, since the inside of the envelope G is in a vacuum state, the gas molecules that are the components of the sealing material 16 fly around in the high vacuum according to the mean free path. Therefore, the scattered gaseous particles travel straight and are adsorbed onto the surface of the shielding member 14 or emitted again depending on their interaction energy with the shielding member 14.

Therefore, if the interaction energy between the shielding member and the sealing material gas molecules is large, most of the gas molecules will be adsorbed and removed by the shielding member 14, so that the filament-shaped cathode 7 and control electrode 6 disposed inside the shielding member 14 will be removed. , the probability of adhesion to the anode A decreases.

Embodiment 2 FIG. 3 is a cross-sectional view showing Embodiment 2 of a chipless fluorescent display tube, in which the luminescent display of the phosphor layer is passed through a mesh-shaped control electrode, a filament-shaped cathode, and a flat plate from the direction of the arrow in the figure. This is a conventional fluorescent display tube for observation. Components common to those in the first embodiment will be described with the same numerals.

The envelope G includes a substrate 1, four side plates 11 erected on the periphery of the substrate 1, and a flat plate 10 facing the substrate 1 at the upper end of the side plates 11, which is formed into a flat box shape by a sealing material 12. It is formed.

On the inner surface of the substrate, a wiring conductor 4 made of Ag, an insulating layer 5 mainly made of low melting point frit glass, and an anode conductor 3 made of carbon are printed and laminated by screen printing. A phosphor layer 8 is deposited on the anode conductor 3. The anode conductor 3 and the phosphor layer 8 constitute an anode A.

A mesh-like control electrode 6 is provided above the anode A, and a filament-like cathode 7 is provided above the anode A.
is stretched by a support member 9.

This support member 9 has a base portion 9a fixed on the substrate 1.
The arm part 9b has elasticity and stands up from the base part 9a. Generally, the support member 9 is made by pressing a metal plate.

On the other hand, an exhaust hole 13 is provided at the end of the substrate 1 under the support member 9. A part of the base portion 9a of one of the supporting members 9 facing above the exhaust hole 13 is raised to form the shielding member 14. In this way, a portion of the cathode support member 9 can be press-molded to serve as the shielding member 14, so that the step of disposing the shielding member 14 can be omitted.

A flat cover member 1 is placed on the outside of the exhaust hole 13 as in the first embodiment.
5 seals an envelope G fixed to the substrate 1 via a sealing material 16. Although there is a possibility that components of the sealing material 16 may be scattered during the sealing process, this is shielded by the shielding member 14 formed from a part of the support member 9.

The surface of the phosphor layer 8 inside the envelope G and the filament-shaped cathode 6 will no longer be contaminated.

Embodiment 3 FIG. 4 is a sectional view of a main part of a chipless fluorescent display tube according to Embodiment 3. The shielding member 14 of this third embodiment has an envelope G
a shielding part 14a provided facing the exhaust hole 13 formed in a part of the support part 14b and a cylindrical part disposed at a position away from the shielding part 14a on the outer periphery of the supporting part 14b and the shielding part 14a. 1
It is composed of 4c. The shielding portion 14a is formed to have approximately the same size as the exhaust hole. The support portion 14b is fixed to the cylindrical portion 14c. The lower end of the cylindrical portion 14c has a flange portion 14d, and the flange portion 14d is connected to the envelope G.
It is fixed at

On the outside of the exhaust hole 13, a flat cover member 15 is attached with an adhesive material 16.
It is bonded and sealed through.

If the cylindrical part 14c is provided on the outer periphery of the shielding part 14a in this way, even if the shielding part 14a is made as small as the exhaust hole 13, the components of the sealing material 16 that cannot be adsorbed and removed by the shielding part 14a will be absorbed into the cylinder. It is removed by adsorption at the shaped part. Therefore, the shielding part 1
4a can be made smaller, the exhaust conductance can be increased, and the adsorption area of the shielding part can be increased.

Example 4 Example 4 shown in FIG. 5 has a structure in which a ring-shaped second shielding part 14e is provided at the upper end of the cylindrical part 14c of Example 3 to increase the suction area. The cylindrical portion 14c does not have a flange portion, and has a structure in which the lower end of the cylindrical portion 14c is adhesively fixed to the envelope with an adhesive 17. Further, as in the third embodiment, a flange portion may be provided and fixed to the envelope G. The rest is the same as in Example 3, so the explanation will be omitted. By providing the second shielding part 14e, it is possible to reduce the height of the cylindrical part 14c, which requires thinning. This embodiment is suitable for the fluorescent display tube which has an excellent space factor.

〔Effect of the invention〕

As explained above, in a chipless fluorescent display tube in which the exhaust hole is sealed with a flat lid member, the present invention provides a shielding member having at least a shielding portion facing the exhaust hole in the vicinity of the exhaust hole in the envelope. Therefore, it became possible to adsorb and remove gaseous components released from the sealing material that appear during sealing using the shielding member. Therefore, the gaseous component of the sealing material does not adhere to the surface of the filamentary cathode or the phosphor layer in the envelope, making it possible to prevent a decrease in the emission of the filamentary cathode. FIG. 7 is a graph showing the pulse emission life characteristics of a chipless fluorescent display tube having a shielding member of the present invention and a conventional chipless fluorescent display having no shielding member.

As can be seen from this graph, the chipless fluorescent display tube of the present invention is superior to the conventional one in all aspects from the initial pulse emission to the pulse emission after 1000 hours of lighting time. The graph of brightness life characteristics in FIG. 8 shows what kind of effect such excellent pulse emission has on a fluorescent display tube.

As can be seen from this graph, the brightness is approximately 10% higher than the conventional product from the initial brightness until 1000 hours have passed.

As described above, the present invention not only has the effect of improving display tube characteristics by increasing the brightness and extending the life of a chipless fluorescent display tube, but also improves the amount of sealing material applied and the amount of coating applied during the sealing process. In practical terms, it is possible to extremely reduce the negative effect on the variation in display tube characteristics caused by variations in accuracy of factors such as position and diameter of the exhaust hole to almost zero, and to produce chipless fluorescent displays with stable quality. The longevity effect is remarkable.

Furthermore, by using the supporting member for the filamentary cathode as the shielding member, the exhaust hole can be provided at the end of the substrate, so that the effective display space can be expanded.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing one embodiment of the present invention, and FIG. 2 is a sectional view showing an embodiment of the present invention.
FIG. 3 is an enlarged sectional view of the main parts of FIG. 1, FIG. 3 is a sectional view of the second embodiment of the present invention, FIG. 4 is an enlarged sectional view of the main parts of Embodiment 3 of the present invention, and FIG. 6 is an enlarged cross-sectional view of the main parts of the fourth embodiment of the present invention, FIG. 6 is a cross-sectional view of the main parts of the conventional chipless fluorescent display tube, and FIG. 7 is the chipless fluorescent display tube of the present invention. FIG. 8 is a graph comparing the pulse emission lifetime characteristics of a conventional chipless fluorescent display tube. FIG. 8 is a graph comparing the brightness lifetime characteristics of the chipless fluorescent display tube of the present invention and a conventional chipless fluorescent display tube. 1... Substrate 7... Filament-shaped cathode 13... Exhaust hole 15... Flat cover member 14a... Shielding part 14... Shielding member 1
4c...Cylindrical part A...Anode G...Envelope Patent applicant Futaba Electronics Co., Ltd. Figure 10 Figure 2 Figure 3 Figure f l'//hehembef

Claims (4)

[Claims] (1) In a chipless fluorescent display tube in which an exhaust hole formed in a part of the envelope of the fluorescent display tube is sealed with a flat lid member via a sealing material, the exhaust hole in the envelope A chipless fluorescent display tube characterized in that a shielding member having a shielding portion is provided in the vicinity at least at a position facing an exhaust hole. (2) The chipless device according to claim 1, wherein the shielding member has an area capable of blocking the components of the sealing material from flowing into the envelope through the exhaust hole. Fluorescent display tube. (3) The chipless fluorescent display tube according to claim 1, wherein the shielding member is formed of a part of a support member that supports a filamentary cathode of the fluorescent display tube. (4) The chipless fluorescent display tube according to claim 1, wherein the shielding member includes a shielding portion and a cylindrical portion provided on the outer periphery of the shielding portion.