JPH0845450A - Fluorescent character display tube - Google Patents

Abstract

PURPOSE:To provide a fluorescent character display tube having a high withstand voltage function. CONSTITUTION:This fluorescent character display tube 1 has an envelope 2 formed out of a front plate 3, a side plate 5 and an electrode substrate 4. A transparent conductive film 6 is formed on the inner surface of the front plate 3. In the envelope 2, a metallic pillar 9 is erected between the substrate 4 and the front plate 3. Furthermore, one end of the pillar 9 is kept in contact with the film 6 for electrical continuity. The other end of the pillar 9 is connected to an external lead 8 via conductive paste 10 and a wiring conductor 7 on the substrate 4. The external lead 8 is led outside through the sealed section of the envelope 2. As a result, a part of an external force acting on the substrate 4 and the front plate 3 of the envelope 2 is supported on the pillar 9 and, therefore, the strength of the envelope 2 becomes high. In addition, the prescribed level of potential is applied from the lead 8 to the film 6 via the reinforcing metallic pillar 9. When the pillar 9 is erected on a presser plate for fixing a negative electrode support, and positioned between the substrate 4 and the front plate 3, deformation due to the thermal deformation of the support or the presser plate can be prevented.

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 having a structure in which, for example, a light emitting display section and electrodes such as a filament cathode are housed inside an envelope. In addition,
The fluorescent display tube of the present invention is not limited to one that performs light emission display of a certain pattern, and one that can display any image,
It also includes a fluorescent display tube used as a light source.

[0002]

2. Description of the Related Art Generally, a fluorescent display tube has an envelope whose inside is kept in a high vacuum state. The envelope 21 of the fluorescent display tube 20 shown in FIGS. 3 and 4 has a box-shaped structure in which a frame-shaped side plate 24 is sandwiched between each outer peripheral portion of a front plate 22 and an anode substrate 23 for sealing. ing. Inside the envelope 21, an anode 25 serving as a light emitting portion including a phosphor is provided on an anode substrate 23. A control electrode (not shown) is provided above the anode 25, and a filamentary cathode 26 is stretched above the control electrode by a cathode support 27.

The cathode support 27 comprises anchors 28 and supports provided at both ends inside the envelope 21, and both ends of the cathode 26 are welded to the anchors 28 and the support, respectively. The anchor 28 shown in FIGS. 3 and 4 is fixed to the upper surface of a pressing plate 29 provided at one end of the anode substrate 23, and its elastic force gives a predetermined tension to the cathode 26. Although not shown, the support is the anode substrate 2
The cathode 26 is fixed to the upper surface of the pressing plate provided at the other end of the cathode 3. Although not shown, a getter may be welded to the pressing plate 29.

Since the pressing plate 29 has a structure that penetrates the sealed portion of the envelope 21 in an airtight manner and projects to the outside, the envelope 2
It is formed of 426 alloy, which has a thermal expansion coefficient close to that of the frit glass used for the sealed portion of No. 1 above. In addition, the cathode support 2
7 is made of stainless steel having an excellent spring property in order to apply a tension to the cathode 26.

As shown in FIG. 4, a transparent conductive film 3 such as an ITO film or a NES film is formed on the inner surface of the front plate 22 of the envelope 21.
0 may be formed. This transparent conductive film 30
Can selectively exert the following two functions depending on the applied potential.

(1) Since the front plate 22 is generally an insulator such as glass, static electricity may be charged from the outside, in which case the display on the anode substrate 23 side may be lost due to the charged static electricity. Therefore, the transparent conductive film 30 is applied with a cathode potential or a constant potential on the positive side of the cathode potential to prevent the front plate 22 from being charged and display defects.

(2) The transparent conductive film 30 is used as an electrode called a diffusion grid. That is, a positive potential is applied to the transparent conductive film 30 to diffuse the electrons emitted from the cathode 26 and reach the anode 25 as uniformly as possible.

In both cases (1) and (2), it is necessary to apply a predetermined potential to the transparent conductive film 30.
For that purpose, the transparent conductive film 30 is electrically connected to the envelope 2
An external lead led out to the outside is required.

Conventionally, in the case of (1), one end of a plate-like contact lead having a spring property is welded to the cathode support 27, and the other end is in contact with the transparent conductive film 30. In the case of (2), external leads electrically independent from the electrodes other than the transparent conductive film 30 in the envelope 21 are provided,
A predetermined voltage was applied to the transparent conductive film 30 via this. The external lead has a plate shape, and one end portion of the envelope which is thinly processed elastically contacts the transparent conductive film 30.

[0010]

Since the inside of the envelope of the fluorescent display tube is maintained in a high vacuum state of 1 × 10 ⁻³ to 1 × 10 ⁻⁴ Pa, it is possible to use the envelope in the atmosphere. Is exposed to atmospheric pressure from the outside. Since the larger the surface area of the fluorescent display tube is, the larger the pressure is applied to the fluorescent display tube. Therefore, the larger the display area of the fluorescent display tube, the larger the thickness of the glass plate constituting the envelope is. However, in such a case, there arises a problem that the weight of the fluorescent display tube becomes large.

The pressing plate and the cathode support are made of different materials and have different thermal expansion coefficients. Therefore, due to the influence of heat applied during manufacturing and the influence of induction heating applied to the getter for flashing the getter, the pressing plate and the cathode support are deformed so as to bulge upward as shown in FIG. There was a problem.

It is an object of the present invention to provide a fluorescent display tube which can secure a sufficient pressure resistance performance even if the material of the envelope is thin and which does not deform the cathode support due to thermal influence.

[0013]

According to a first aspect of the present invention, there is provided a fluorescent display tube including a front plate having a transparent conductive film on an inner surface thereof, an anode substrate facing the front plate at a predetermined distance, and the front plate. In a fluorescent display tube including an envelope having a side plate sealed between the anode plate and the anode substrate, the fluorescent display tube is erected upright between the front plate and the anode substrate and has one end electrically connected to the transparent conductive film. A metal member, an outer lead that hermetically penetrates the envelope, and a conductive member that electrically connects the other end of the metal strut and the outer lead.

According to a second aspect of the present invention, there is provided the fluorescent display tube according to the first aspect, wherein the conductive member is formed on an inner surface of the anode substrate and the end portion of the outer lead inside the envelope. And a conductive paste that conducts the wiring conductor and the metal member.

According to a third aspect of the present invention, there is provided the fluorescent display tube according to the first or second aspect, wherein the metal member is a metal column.

According to a fourth aspect of the present invention, there is provided the fluorescent display tube according to the first aspect, characterized in that a pressing plate as the external lead is provided with a cathode support as the conductive member. There is.

[0017]

The transparent conductive film is electrically led out of the envelope via the metal member, the conductive member and the external leads. The metal member provided between the front plate of the envelope and the anode substrate supports the atmospheric pressure applied to the outer surfaces of the front plate of the envelope and the anode substrate,
Improves the pressure resistance of the envelope.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A fluorescent display tube 1 of a first embodiment will be described with reference to FIG. The envelope 2 of the fluorescent display tube 1 has a box-like structure in which a frame-shaped side plate 5 is sandwiched between the front plate 3 and each outer peripheral portion of the anode substrate 4 and sealed. Each member constituting the envelope 2 is glass, and is sealed with low melting point frit glass.

Although not shown in FIG. 1, inside the envelope 2, an anode serving as a light emitting portion having a phosphor is provided on the anode substrate 4. A control electrode (not shown) is provided above the anode, and a filamentary cathode is stretched above the control electrode by a cathode support. The structure of the cathode support and the pressing plate to which the cathode support is attached is the same as the conventional one. In addition, a transparent conductive film 6 such as an ITO film or a Nesa film is formed on the inner surface of the front plate.

As shown in FIG. 1, a wiring conductor 7 as a conductive member is formed on the upper surface of the anode substrate 4 in the envelope 2. The wiring conductor 7 serves as a connection point with another member 2
It has a shape including individual connection end portions 7a and 7b and a thin conductor portion 7c connecting both connection end portions 7a and 7b. One connecting end 7a is located near the sealed portion of the envelope 2, and the other connecting end 7b is located inside the envelope 2 more than that. The wiring conductor 7 is formed of, for example, an aluminum thin film.

External leads 8 are hermetically inserted through the sealed portions of the anode substrate 4 and the side plate 5. The inner end of the outer lead 8 is connected to one connection end 7a of the wiring conductor 7. The outer ends of the external leads 8 are connected to a drive circuit (not shown) or the like, and a predetermined voltage is applied to the external leads 8.

On the other connecting end portion 7b of the wiring conductor 7 on the inner side of the envelope 2, a metal pillar 9 as a metal member is erected. One end of the metal column 9 is in electrical contact with the transparent conductive film 6 on the inner surface of the front plate 3 by being in contact therewith. The other end of the metal column 9 is fixed to the connection end 7b by a conductive paste 10 as a conductive member and is electrically connected. The conductive paste 10 is a mixture of frit glass and Ag powder as a conductive material. The metal column may be a solid column, or may be formed by pressing a metal plate material into a U shape or an L shape so as to increase the pressure resistance.

That is, the metal pillars 9 are mounted on the anode substrate 4 by the conductive paste 10 and are fixed by being sandwiched between the anode substrate 4 and the front plate 3.
And it functions as a support pillar for supporting an external force applied to the front plate 3. Therefore, the metal pillar 9 and the transparent conductive film 6
Since the conductive paste 10 ensures the electrical continuity between the metal support 9 and the connection end 7b, the electrical connection between the metal support 9 and the connection end 7b is also ensured. It has become.

Therefore, the transparent conductive film 6 on the inner surface of the front plate 3 is formed.
Is a metal pillar 9, a conductive paste 10, and a wiring conductor 7.
And is electrically led out to the outside of the envelope 2 via the external lead 8. A predetermined voltage can be applied to the transparent conductive film 6 from the outer end of the outer lead 8.

In FIG. 1, one metal support column 9 connected to the external lead 8 via the wiring conductor 7 and the like is shown.
Depending on the size of the envelope 2 and the thickness of the glass material such as the front plate 3 and the anode substrate 4, two or more required metal columns may be arranged in the envelope 2. In that case, at least one of the plurality of metal columns may electrically lead the transparent conductive film 6 to the outside of the envelope 2 in the structure shown in FIG. . When the display area of the fluorescent display tube is large and the area of the transparent conductive film is large or the transparent conductive film is separated into a plurality of pieces, two or more metal columns for guiding the transparent conductive film to the outside of the envelope are provided. .

The metal column 9 of this embodiment has a cylindrical shape. The material is 426 alloy, which is well compatible with glass materials, but the surface is oxidized to blacken it, and the surface metallic treatment such as plating and coloring removes the metallic luster of the surface. Therefore, the metal column 9 has a low light reflectance, and even if it is arranged within the display portion of the fluorescent display tube 1, it does not hinder the visual recognition of the display.

The metal columns 9 are attached by using an automatic attaching machine having a function of holding and conveying a work and setting it at a predetermined position. First, the metal pillar 9 is positioned at a predetermined position on the anode substrate 4, and the metal pillar 9 is erected on the anode substrate 4 by the conductive paste 10 previously applied at the same position. The whole of the anode substrate 4 or the portion of the conductive paste 10 is heated, and the metal pillar 9 is fixed on the anode substrate 4 by the conductive paste 10 which is melted and then solidified. After that, when the envelope 2 is assembled according to the manufacturing process of the fluorescent display tube 1, the metal columns 9 are fixed in the envelope 2 while being erected between the anode substrate 4 and the front plate 3.

A zero or positive potential is applied to the external lead 8 with respect to the cathode. When the fluorescent display tube 1 is driven, the electrons emitted from the cathode are diffused and uniformly reach the anode.

According to this embodiment, at least a part of the external force applied to the front plate 3 and the anode substrate 4 of the envelope 2 is covered by the metal support column 9.
Is supported, the strength of the envelope 2 is improved. Therefore, if the envelope has the same outer shape, a thinner glass plate can be used as a constituent material.

Referring to FIG. 2, the fluorescent display tube 1 of the second embodiment.
1 will be described. The envelope 12 of the fluorescent display tube 11 has a box-shaped structure in which a frame-shaped side plate 15 is sandwiched between the front plate 13 and each outer peripheral portion of the anode substrate 14 and sealed. Each member constituting the envelope 12 is glass, and is sealed with low melting point frit glass.

Although not shown in FIG. 2, inside the envelope 12, an anode serving as a light emitting portion having a phosphor is provided on the anode substrate 14. A control electrode (not shown) is provided above the anode, and a filamentous cathode 16 is stretched above the control electrode. Further, a transparent conductive film 17 such as an ITO film or a Nesa film is formed on the inner surface of the front plate 13.

The structure of the cathode support and the pressing plate to which the cathode support is attached is the same as in the first embodiment. First,
At both ends of the envelope 12, a pair of pressing plates 29 are provided so as to penetrate the sealed portion of the envelope 12 in an airtight manner. One end of the pressing plate 29 protruding to the outside of the envelope 12 serves as an external lead for the cathode. Each pressing plate 29 has
The anchor 28 and the support forming the cathode support 27 are welded to each other. The support fixes one end of the cathode 16, and the anchor 28 pulls the other end of the cathode 16 to apply tension to the cathode 16. FIG. 2 shows the pressing plate 29 on the side where the anchor 28 is fixed. The pressing plate 29 is made of 426 alloy, which is well-suited to glass, and the anchor 2
8 and the support are made of stainless steel having excellent spring properties.

On the base plate portion 28a of the anchor 28 fixed to the pressing plate 29, the metal columns 18 are erected. The structure and the fixing structure of the metal column 18 are substantially the same as those in the first embodiment. That is, the metal support 18 is used for the anode substrate 14
It is fixed between an anchor 28 fixed to an upper holding plate 29 and the front plate 13 facing the anode substrate 14, and supports pressure applied to the anode substrate 14 and the front plate 13. One end of the metal column 18 is in contact with the transparent conductive film 17 so as to be electrically conductive, and the other end thereof is attached to the anchor 28 and electrically connected to the pressing plate 29.

At least one metal pillar 18 is erected on the cathode support 27 (the anchor 28 or a support (not shown)) and is brought into contact with the transparent conductive film 17. Similar to the first embodiment, metal columns that do not contact the transparent conductive film may be additionally provided.

A driving voltage for the cathode 16 is applied to the outer end of the pressing plate 29. The same potential as the cathode 16 is applied to the transparent conductive film 17. Therefore, the front plate 13 is not charged with electrons.

According to this embodiment, the same effect as that of the first embodiment can be obtained, and further, the pressing plate 29 and the cathode support 27 can be prevented from being deformed by heat.

[0037]

According to the present invention, the following effects can be obtained. (1) Since the pressure resistance of the envelope is improved and the thickness of the glass plate that is a constituent material of the envelope can be reduced, the display device can be easily enlarged.

(2) In order to lead out the transparent conductive film provided on the inner surface of the envelope to the outside of the envelope, prepare a dedicated connection conducting member such as a contact lead that contacts the transparent conductive film inside the envelope. It is not necessary to do so, and a metal strut having a function of supporting the strength of the envelope can achieve the same function as a conventional contact lead.

(3) The deformation of the cathode support due to heat can be prevented. (4) Since the vertical vibration of the pressing plate supporting the cathode support can be prevented, it is possible to suppress the contact between the filament cathode and the control electrode and the generation of the collision noise between the pressing plate and the anode substrate.

[Brief description of drawings]

FIG. 1 is a perspective view of a first embodiment.

FIG. 2A is a plan view of a second embodiment, and FIG. 2B is a plan view of FIG.
It is sectional drawing in the AA cutting line of.

FIG. 3 is a plan view of a conventional fluorescent display tube.

FIG. 4 is a view showing one of the problems in the conventional fluorescent display tube and is a cross-sectional view taken along the line BB of FIG.

[Explanation of symbols]

 1,11 Fluorescent display tube 3,13 Front plate 4,14 Anode substrate 5,15 Side plate 6,17 Transparent conductive film 7 Wiring conductor as a conductive member 8 External lead 9,18 Metal support 10 Conductive paste as a conductive wire member 27 Cathode support as conducting wire member 29 Holding plate as external lead

Claims (4)

[Claims] 1. A front plate having a transparent conductive film on an inner surface thereof, an anode substrate facing the front plate at a predetermined distance, and a side plate sealed between the front plate and the anode substrate. In a fluorescent display tube including an envelope, a metal member that is erected between the front plate and the anode substrate and has one end electrically connected to the transparent conductive film, and an external lead that hermetically penetrates the envelope. And a conductive member for electrically connecting the other end of the metal column to the external lead. 2. The conductive member comprises a wiring conductor formed on an inner surface of the anode substrate and electrically connected to an end portion of the outer lead inside the envelope, and a conductive paste for electrically connecting the wiring conductor and the metal member. The fluorescent display tube according to claim 1. 3. The metal member is a metal strut.
Alternatively, the fluorescent display tube according to item 2. 4. The fluorescent display tube according to claim 1, wherein a cathode support as the conductive member is attached to the pressing plate as the external lead.