Electron tube having linear damper

An electron tube includes a vessel, a primary linear member installed in the vessel, an electrode disposed in the vessel, a first auxiliary linear member and a second auxiliary linear member disposed at different heights to interpose the primary linear member therebetween, and a plurality of fixing members. The fixing members are formed at a single substrate for constituting a part of the vessel, for fixing end portions of the first auxiliary and the second auxiliary linear member thereto.

FIELD OF THE INVENTION

The present invention relates to an electron tube, for instance, a fluorescent display tube having a linear member such as a cathode filament, a linear grid and a linear getter; and, more particularly, to a fixing structure of an auxiliary linear member, such as a linear damper and a linear spacer, for restricting the movement of the linear member.

BACKGROUND OF THE INVENTION

Referring toFIGS. 11A to 13, a conventional electron tube, e.g., a conventional fluorescent display tube, will now be described in detail. Like reference numerals inFIGS. 11A to 13represent like parts and, if there are a plurality of same elements, only one will be designated by a reference numeral.

FIGS. 11A and 11Bshow a prior art fluorescent display tube equipped with a plurality of pairs of insulating supports (dampers) such as a metal line coated with an insulator or a glass fiber, wherein the dampers are correspondingly arranged at an upper and a lower side of a cathode filament, respectively, thereby forming a pair (see, for instance, Japanese Patent Laid-Open Publication No. 1984-146139, in particular FIG. 3).

FIGS. 11A and 11Bpresent a cross sectional view seen in a direction indicated by arrows after cutting along a line X2—X2ofFIG. 11Band a top view seen in a direction indicated by arrows after cutting along a line X1—X1ofFIG. 11A, respectively.

The prior art fluorescent display tube includes a front substrate11and an anode substrate12facing each other. Formed on inner surfaces of the front substrate11and the anode substrate12are a transparent conductive film111and an anode electrode121coated with a fluorescent substance, respectively. There are provided between the two substrates11,12a cathode filament21and a grid24for controlling electrons emitted from the filament21. The electrons emitted from the cathode filament21cause the fluorescent substance of the anode electrode121to radiate light.

In case the fluorescent display tube has a lengthy filament21or is mounted on an automobile, the filament21may vibrate and may come into contact with other components or the substrates of the display tube. In order to prevent such contact, there are disposed a plurality of pairs of dampers221and222, wherein the dampers221,222are correspondingly arranged at the upper and the lower side of the filament21, respectively. The pairs of dampers are spaced apart from each other at a predetermined interval.

Referring toFIGS. 12A and 12B, there are shown another prior art fluorescent display tube including a front substrate where a plurality of dampers made of a metal line are arranged at one side of a cathode filament (see, for example, Japanese Patent Laid-Open Publication No. 2002-245925, in particular FIG. 5), whereinFIG. 12Ais a cross sectional view seen in a direction indicated by arrows after cutting along a line X4—X4ofFIG. 12B; andFIG. 12Bis a top view seen from a direction indicated by an arrow X3shown inFIG. 12A.

The damper22made of a metal line is installed at one side of the filament21, such that one end of the damper22is interposed between a metal layer31such as an aluminum thin film formed on the front substrate11and a metal piece32such as an aluminum wire, by an ultrasonic bonding to thereby wedge one end of the damper22by the metal layer31together with the metal piece32. The damper22has a predetermined vertical position maintained by a use of a spacer33made of, e.g., a metal line.

In the first prior art display tube, an issue of how to fix ends of the dampers221,222installed at both sides of the filament21is addressed. As one method of fixing the dampers221, a scheme depicted inFIG. 13can be conceived by adopting the fixing method of the second prior art display tube shown inFIGS. 12A and 12B(the scheme has not been disclosed).

As illustrated inFIG. 13, a lower damper221is fastened to a front substrate11, while an upper damper222is fastened to an anode substrate12. The damper221has both ends fixedly attached to a pair of metal layers311together with a corresponding pair of the metal pieces321by using the ultrasonic bonding technique. Similar to the damper221, both ends of the damper222are fixedly attached to a pair of metal layers312with the metal pieces322by the same bonding technique.

In this case, the fixing process of the dampers221,222is repeatedly performed at four locations in the front substrate11and the anode substrate12. For this reason, a space for installing the metal layers311,312and the spacers331,332is enlarged, thereby increasing so-called dead space which is not useful in a display function of the fluorescent display tube. In addition, since manufacture and installation processes of the metal layers311,312and the spacers331,332increase and a large number of members are needed therefor, the production costs of the fluorescent display tube may rise. Further, in case of providing the dampers221,222with wirings, the wirings need to be prepared in the front substrate11and the anode substrate12separately, which in turn doubles the number of wirings and terminals needed therefor.

SUMMARY OF THE INVENTION

It is, therefore, an object of the present invention to provide an electron tube capable of reducing a space for fixing one or more pairs of auxiliary linear members, the number of process and member therefor, and the number of wiring thereof and terminal for extracting the wirings to an outside by fixing one or more pairs of auxiliary linear members to a common fixing member or separated fixing members formed on a same substrate.

In accordance with the present invention, there is provided an electron tube comprising:

a vessel;

a primary linear member installed in the vessel;

an electrode disposed in the vessel;

a first auxiliary linear member and a second auxiliary linear member disposed at different heights to interpose the primary linear member therebetween; and

a plurality of fixing members, formed at a single substrate for constituting a part of the vessel, for fixing end portions of the first auxiliary and the second auxiliary linear member thereto.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring toFIGS. 1 to 10, a fluorescent display tube of an electron tube type in accordance with a preferred embodiment of the present invention will now be described in detail. Like reference numerals in the drawings represent like parts and, if there are a plurality of same elements, only one will be designated by a reference numeral.

FIGS. 1A to 1Cshow a fluorescent display tube in accordance with the preferred embodiment of the present invention, whereinFIG. 1Aoffers a cross sectional view seen in a direction indicated by arrows after cutting along a line Y1—Y1ofFIG. 1C;FIG. 1B, a cross sectional view seen in a direction indicated by arrows after cutting along a line Y2—Y2ofFIG. 1C; andFIG. 1C, a top view seen in a direction indicated by arrows after cutting along a line Y3—Y3ofFIG. 1A.

The fluorescent display tube includes a sealed vessel (a container) provided with at least a front substrate11and an anode substrate12(a first substrate and a second substrate, respectively), wherein the substrates11,12are made of an insulating material such as glass or the like and disposed to face each other. The front substrate11and the anode substrate12are hermetically sealed by using side plates131to134made of an insulating material such as glass and fritted glass(not shown) to thereby form the sealed vessel. The sealed vessel can be formed by hermetically sealing the substrates11,12by using only the fritted glasses without using the side plates131to134(in the case, the vessel or the fritted glass include a spacer). Thus, the side plates131–134and the fritted glasses will be referred to as side members.

There are formed on inner surfaces of the front substrate11and the anode substrate12a transparent conductive film (NESA electrode)111and a plurality of anode electrodes121on which a fluorescent substance (not shown) is applied. Disposed between the substrates11and12are hot cathode filaments F (linear members) and a pair of conductive dampers D1, D2(auxiliary linear members disposed above and below the linear members) for preventing the vibration of the filaments F. The pair of linear dampers D1, D2symmetrically arranged with respect to the filament F are hung tightly in a direction intersecting the filaments F and a plurality of such pairs are installed along a longitudinal direction of the filaments F at a predetermined interval.

Electrons discharged from the filaments F excite the fluorescent substance applied on a selected anode electrode121, thereby making the fluorescent substance radiate light. By applying a predetermined voltage to the transparent conductive film111on the front substrate11, the front substrate11is prevented from being charged with electricity and, at the same time, the electrons from the filaments F can be uniformly diffused to the selected anode electrode121.

The pair of corresponding dampers D1, D2are symmetrically arranged below and above the filaments F respectively and are kept out of contact with the filament F when the filaments F are not vibrated. In case that the filaments F vibrate due to a shock from the outside, the filaments F come into contact with the dampers D1, D2, which serve to stop the filament F from vibrating, thereby preventing the filament F from being in contact with, e.g., the anode electrode121. The linear electrode such as the filaments F, to which a voltage is applied (to heat same), is preferably disposed in such a manner to be in contact with the dampers D1, D2, only when the linear electrode is vibrates. Otherwise, under a constant contact with the dampers D1, D2, the filament F loses heat through the dampers D1, D2, which in turn reduces the electron emission at the contact portion and results in a deterioration of the display quality. A linear member to which a voltage is not applied may be in contact with the dampers all times.

Both ends of each of the damper D1, D2are fixed to conductive spacer pads SP (fixing members) made of an aluminum wire such as a bonding wire. The spacer pads SP are ultrasonically bonded to aluminum thin films (metal layers)112formed on the front substrate11. One end of the damper D1is embedded in a fixing portion SP1, specifically, between a bottom portion and a vertical portion thereof, by the ultrasonic bonding, wherein the fixing portion SP1having a step shape is located in an offset position of the spacer pad SP. In the same manner, one end of the damper D2is fixed to a fixing portion SP2of the spacer pad SP. Herein, the ends of each damper can be embedded in such manners that: {circle around (1)} the whole end portion placed in the fixing portion is completely embedded, such that a surface thereof not exposed to the outside; {circle around (2)} the end portion is partially embedded, such that parts of the surface thereof is exposed to the outside; and {circle around (3)} a part of the end portion is completely embedded not to be exposed therefrom, whereas the remaining part thereof is partially embedded, such that parts of the surface thereof is exposed to the outside (combination of {circle around (1)} and {circle around (2)}).

The vertical position of the damper D1is defined by the height of the bottom portion of the fixing portion SP1, while that of the damper D2is defined by the height of a top portion SP3thereof. The height of the top portion SP3serving as a spacer portion depends on the diameter of the Al wire constituting the spacer pad SP.

Both ends of the filament F are fastened to step-shaped fixing portions of conductive spacer pads114made up of an aluminum wire (a bonding wire) by using the ultrasonic bonding. The spacer pad114is ultrasonically bonded to an aluminum thin film (a metal layer)113of a cathode wiring formed on the front substrate11. The vertical position of the filament F is determined by the diameter of the Al wire.

The first exemplary display tube has the pair of dampers D1, D2capable of being fastened only to the front substrate11(a same substrate) and, further, one spacer pad SP is used for fixing the corresponding ends of the two dampers D1, D2. Since the spacer pad SP functions both as the fixing member and the spacer, there is no need to prepare the two members separately as in the conventional display tubes. Further, the spacer pad SP is a single member but can define two different vertical positions.

The whole part or a large part of the end portions of the dampers D1, D2are embedded in the spacer pads SP along the bottom portions and the vertical portions of the stepped-shaped fixing portions SP1, SP2thereof, respectively. Since this allows an area of the end portions of the dampers D1, D2joined to the spacer pads SP to be enlarged, the dampers D1, D2have sufficient portions joined thereto thereby increasing the binding strength.

In case of providing the dampers D1, D2with the wirings, one wiring or one terminal for extracting the wiring can be commonly used for both dampers D1, D2, as will be described later, and, therefore, it is not required to increase the numbers thereof.

Furthermore,FIGS. 1A to 1Crepresent a diode without installing a grid between the filament F and the anode electrode121. However, multi electrode tube having one or more grids between the damper D2and the anode electrode121can be employed.

Hereinafter, the preferable size of each part of the fluorescent display tube ofFIGS. 1A to 1Cwill now be explained.

The front substrate11and the anode substrate12both have a thickness ranging from about 0.9 to 1.1 mm and the distance between the substrates11,12ranges from about 0.9 to 1.1 mm. The dampers D1, D2are constituted by a metal line, made of, e.g., tungsten, having a diameter of about 0.03 mm (about 2 MG), and the spacer pad SP is constituted by an Al wire with a diameter of about 500 μm. Further, when the vertical position of the filament F is changed, the diameter of the Al wire of the spacer pad SP is required to be changed accordingly.

The spacer pad114is made of the Al wire having a diameter ranging from about 0.1 to 1.0 mm, but in the preferred embodiment of the present invention the Al wire is set to have a diameter of about 0.4 mm. The Al thin films112,113formed by sputtering method have a thickness of greater than 0.1 μm for both. Moreover, the Al thin films112,113may be replaced with a thick film with a thickness of greater than 10 μm, which is obtained by printing.

The filament F has a metal core wire coated with a ternary carbonate for electron emission, such as Ba, Sr or Ca, wherein the core wire in the present invention is made of tungsten or a tungsten alloy and has a width of about 0.4 MG (a diameter of about 14 μm). However, the core wire may have a width ranging from 0.3 MG (a diameter of about 10 μm) to 7.35 MG (a diameter of about 50 μm).

The spacer pad SP is fixedly attached to the front substrate11by ultrasonic-bonding the Al wire. When the spacer pad SP is fixed, the top portion SP3has a height of 380 μm and the bottom portions of the fixing portions SP1, SP2have a height of 230 μm. The height of the spacer pad114fixed to the front substrate11, that is, the vertical position of the filament F is set to be 320 μm.

If the Al wire of the spacer pad SP has an uniform width, the heights of the fixing portions SP1, SP2and the top portion SP3thereof can be controlled by changing the ultrasonic output of an ultrasonic bonding device, the bonding time and the load of a bonding tool. The height of the spacer pad114can also be controlled in a similar fashion.

Pairs of the dampers D1, D2are disposed to be apart from each other by a distance ranging from about 10 to 20 mm along a longitudinal direction of the filament F.

The dampers D1, D2and the filament F preferably include a tension force apply portion (a spring portion) such as a coiled portion in order to apply the tension force thereto. Same is applied to the other preferred embodiments described below.

Referring toFIGS. 2A to 2H, the ultrasonic-bonding processes of the spacer pad SP and the dampers D1, D2will now be described.

First, the spacer pad SP made of the Al wire is mounted on the Al thin film112formed on the front substrate11and then is pressed with an ultrasonic bonding tool (a wedge tool) T1against the Al thin film112. The ultrasonic is applied to the tool T1so that the spacer pad SP is joined to the Al thin film112(seeFIG. 2A). Thereafter, the damper D1is mounted on thus fixed spacer pad SP and pressure is given to a part of the spacer pad SP and the damper D1by using an ultrasonic bonding tool T2. By applying the ultrasonic to the tool T2, the damper D1is joined to the spacer pad SP (seeFIGS. 2B and 2C). The damper D1is joined to the step-shaped fixing portion SP1of the spacer pad SP. The extra portion of thus joined damper D1is cut off (seeFIG. 2D).

Next, the filament F is disposed not to be in contact with the damper D1and then bonded to the spacer pad114shown inFIG. 1(seeFIG. 2E). Thereafter, the damper D2is mounted on the spacer pad SP not to be in contact with the filament F and the ultrasonic is applied to the ultrasonic bonding tool T2pressing another part of the spacer pad SP and the damper D2, thereby fixing the damper D2to the spacer pad SP (seeFIGS. 2F and 2G). The damper D2is joined to the step-shaped fixing portion SP2of the spacer pad SP. Finally, the extra portion of thus joined damper D2is cut off so that the fixing process of the dampers D1, D2is completed (seeFIG. 2H).

Herein, the ultrasonic bonding was carried out under the condition where the output of the ultrasonic: 60 W, the load of the ultrasonic bonding tool: 600 g, and the bonding time: 50 m sec. The binding strength (a fixing strength) of the dampers D1, D2is about 30 g, which is equal to or more than the line strength of the dampers D1, D2(about 30 g).

FIGS. 3A to 3Cand4A to4C illustrate the positions of the dampers D1, D2fixed to the spacer pad SP in a manner to face to each other.

FIGS. 3A and 4Apresent cross sectional views seen in a direction indicated by arrows after taken along a line Y5—Y5ofFIGS. 3C and 4C, respectively;FIGS. 3B and 4Bpresent cross sectional views seen in a direction indicated by arrows after taken along a line Y6—Y6ofFIGS. 3C and 4C, respectively; andFIGS. 3C and 4Coffer top views seen in a direction indicated by arrow Y4ofFIGS. 3A and 4A, respectively.

InFIGS. 3A to 3C, the dampers D1, D2are respectively arranged below and above the filament F in the intersecting direction thereof. The ends of the dampers D1, D2are ultrasonic-bonded to the step-shaped fixing portions SP1, SP2, respectively, in a manner that the dampers D1, D2are vertically, symmetrical with respect to a certain point of the filament F. The vertical positions of the dampers D1, D2are defined by the heights of the fixing portion SP1, SP3, respectively.

InFIGS. 4A to 4C, the dampers D1, D2are disposed below and above the filament F, respectively, in a manner not to vertically correspond to each other and then fixed to the spacer pad SP by the ultrasonic bonding.

It is possible to fix the damper D1to the fixing portion SP2. In this case, the fixing portion of the damper D1is leveled with or lower than the fixing portion SP2shown inFIGS. 4A to 4Cand the top portion for mounting thereon the damper D1is lower than the top portion SP3shown inFIGS. 4A to 4Cand leveled with the bottom portion of the fixing portion SP1shown inFIG. 4.

Such configurations illustrated inFIGS. 3 and 4have the same effect in view of preventing the vibration of the filament F. Accordingly, it is not necessary to vertically align the dampers D1, D2symmetrically about a certain point of the filament F while fixing the dampers D1, D2to the spacer pad SP. Accordingly, the fixing process of the dampers can be carried out more easily.

FIGS. 5A to 5Cdescribe an example of fixing the dampers disposed above and below the filament to the spacer pads prepared on a same substrate, whereinFIG. 5A: a cross sectional view seen in a direction indicated by arrows after taken along a line Y1—Y1ofFIG. 5C,FIG. 5B: a cross sectional view seen in a direction indicated by arrows after taken along a line Y2—Y2ofFIG. 5CandFIG. 5C: a top view seen in a direction indicated by arrows after taken along a line Y3—Y3ofFIG. 5A.

The dampers D1, D2(auxiliary linear members) are alternately arranged below and above the filament F (a linear member having auxiliary linear members therebelow and thereabove), respectively. Then the damper D1is fastened to a lower spacer pad SPD1(a fixing member) and the damper D2is fixed to an upper spacer pad SPD2(a fixing member). One end of the damper D1is joined to a step-shaped fixing portion SPD11of the lower spacer pad SPD1by using the ultrasonic bonding. In the same manner, the end of the damper D2is ultrasonic-bonded to a step-shaped fixing portion SPD21of a spacer pad SPD2. The spacer pads SPD1, SPD2are fixedly attached to the corresponding Al thin films112(metal layers) on the front substrate11(a same substrate) by the ultrasonic bonding.

In this case, more spacer pads are needed but the number of the dampers used therefor is reduced. Moreover, since each of the spacer pads SPD1, SPD2has only one damper D1, D2fixed thereto, there can be secured a large ultrasonic boding space for each damper, thereby obtaining the increasing binding strength.

FIGS. 6A to 6Cand7A to7C depict an intermediate spacer pad disposed at the middle point of the damper.

FIGS. 6A and 7Aare cross sectional views seen in a direction indicated by arrows after taken along a line Y5—Y5ofFIGS. 6C and 7C, respectively;FIGS. 6B and 7B, cross sectional views seen in a direction indicated by arrows after taken along a line Y6—Y6ofFIGS. 6C and 7C, respectively; andFIGS. 6C and 7C, top views seen in a direction indicated by an arrows Y4shown ofFIG. 6A and 7A, respectively.

InFIGS. 6A to 6C, a conductive intermediate spacer pad ISP is fixedly attached to an Al thin film115(a metal layer) of the front substrate11(a same substrate) by using the ultrasonic bonding. Then dampers D11, D12(a plurality of auxiliary linear members) are fixed to the intermediate spacer pad ISP (a fixing member) in such a manner that one of the dampers D11, D12extends to the right and the other extends to the left therefrom. The ends of the dampers D11, D12are ultrasonic-bonded to their corresponding step-shaped fixing portions ISP11, ISP12. The dampers D11, D12have the same vertical position which is determined by the height of bottom portions of the fixing portions ISP11, ISP12.

In general, the intermediate spacer pad is useful in case of the lengthy damper. However, in most cases, the pad is installed in the display area and, therefore, the smallest installation space therefor is preferable. The spacer pad ISP ofFIGS. 6A to 6Chas an advantage in point of the installation space because only one spacer pad ISP is installed for both dampers D11, D12.

InFIGS. 7A to 7C, the filament F (not shown) has the dampers D11, D12shifted to each other in a longitudinal direction thereof. The end of the damper D11is bonded to the fixing portion ISP11by using the ultrasonic bonding and that of the damper D12is bonded to the fixing portion ISP12by the same way. The vertical positions of the dampers D11, D12are defined by the height of a top portion ISP3.

There are described inFIGS. 6A to 6Cand7A to7C the description of fastening the lengthy damper tightly. However, it may be applied to other lengthy linear members such as a filament or a wire grid for the purpose of tightly fastening same.

FIG. 8shows an example of the intermediate spacer pad for fixing the corresponding dampers placed respectively below and above the filament.

The intermediate spacer pad ISP has a three-stepped structure where the first and the second steps from the bottom constitute the fixing portions. One end of each dampers D11, D12is ultrasonic-bonded to the lower fixing portions ISP11, ISP12, respectively, while that of each dampers D21, D22is ultrasonic-bonded to upper fixing portions ISP21, ISP22, respectively. The other ends of the respective dampers D11, D12, D21, D22are fixed to the spacer pads SP, respectively, by using the ultrasonic bonding.

InFIGS. 9A and 9B, a pair of dampers disposed above and below the filament in the cross direction thereof are fixed to the same substrate by using separate spacers for each damper.

First, the structure depicted inFIG. 9Awill now be explained. The end of the damper D1(a lower auxiliary linear member) is bonded to the Al thin film112(a metal layer) on the front substrate11(a base) by applying the ultrasonic to an Al wire1512(a fixing member and spacer member). Similarly, the end of the damper D2(an upper auxiliary linear member) is bonded to the Al thin film112by applying the ultrasonic to an Al wire1511(a fixing member). Thus, the two dampers are fixed to the same Al thin film112. The Al wire1512also functions as a spacer for the damper D2. The reference numeral1513represents a spacer for the damper D1.

InFIG. 9A, the Al wire1512performs a double duty as the fixing member of the damper D1or the spacer of the damper D2, thereby saving the installation of any one of the fixing member and the spacer in comparison with the case of fixing both dampers to the separate fixing members.

Next, the structure ofFIG. 9Bwill now be described. The end of the damper D1(a lower auxiliary linear member) is bonded to the Al thin film112(a metal layer) by applying the ultrasonic to an Al wire1514(a fixing member), while the end of the damper D2(an upper auxiliary linear member) is bonded to a step-shaped fixing portion of the Al wire1514by using the ultrasonic bonding, so that the two dampers are fixed to the common Al thin film112formed on the front substrate11(a base).

In this case, the Al wire1514is a fixing member of the damper D1. At the same time the Al wire1514serves both as the spacer member and the fixing member of the damper D2. Therefore, the Al wire1511shown inFIG. 9Ais not necessary.

In the examples illustrated inFIGS. 9A and 9B, the dampers D1, D2can be fixed to the same substrate, thereby facilitating the fixing process. Moreover, the fixing member of one damper can also be used as the spacer of the other damper so that the number of the spacers or the fixing members can be reduced.

There is described inFIG. 10an arrangement of wirings prepared on the front substrate11.

Formed in a flat shape on the front substrate11is the transparent conductive film111, to which a wiring FW is connected. The filament F has the plurality of pairs of corresponding dampers D1, D2arranged respectively below and above the filament. Each pair is connected to a wiring DW which is connected to a resistor R. While the filament F comes into contact with the dampers D1, D2, the resistor R prevents a current of the filament F from flowing into the dampers D1, D2. Further, the Al thin film113serves as a cathode wiring. The reference numeral116represents a getter.

In this case, since a single wiring DW works for both dampers D1, D2arranged below and above the filament F, the number of the wirings is reduced by half, compared with the case of connecting the wiring DW to each damper. Further, the number of the terminals (not shown) connected to the wirings DW is also halved.

Though the damper and the spacer pad for the filament are made of the Al wire in the preferred embodiment of the present invention, the material thereof is not limited to aluminum. A metal such as Cu, Au, Ag, Ni, Pt or V, suitable for fabricating and bonding can be employed therefor. Further, the cross sectional shape of the spacer pad is not limited to the circular or the elliptical shape. It may be a rectangular shape or the like. As the material of the thin film for fixing the spacer pad, aluminum is employed but any one of Cu, Au, Ag, Ni, Pt and V can be adopted instead of aluminum. Further, the Al thin film can be formed at the surface of the sealed vessel or on the components in the vessel via an insulating layer. The Al thin film is not limited to the thin film and may be a thick film made of a metal. Therefore, it is referred to as a metal layer in the present invention.

Furthermore, it is preferable that the spacer pad and the metal layer are made of the similar metallic material (e.g., Al and Al alloy) in terms of the binding strength. Most preferably, they are made of the same metallic material (e.g., Al alloy and Al alloy).

The above-described spacer pad used to fix the damper in the preferred embodiment, is not limited thereto, and it may be used to fix other linear members such as the filament and the wire grid. Further, though there are disposed a plurality of linear members in the preferred embodiment, only one linear member can be employed.

A pair of dampers are fixed to the same spacer pad on the same substrate in the preferred embodiment, but two or more pairs of dampers can be fixed thereto.

In the preferred embodiment, the ultrasonic bonding technique is used to fix the members but another technique may be employed therefor.

Furthermore, dampers are fixed to the front substrate in the preferred embodiment but they may be fixed to the anode substrate, the side plate, the electrode substrate(e.g., grid intermediate substrate in the sealed vessel) or the components in the sealed vessel.

Though the end of the linear member is placed in the outer end potion of the conductive spacer in the preferred embodiment, the location thereof is not limited thereto if the linear member can be fixed.

The fixing portion for fixing the dampers are formed at the end portion of the spacer pad, but it may be formed at another location, e.g., the intermediate portion thereof.

There are described the fluorescent display tube in the present invention, but it may be, a display tube such as a fluorescent radiation device or a CRT, a discharge tube such as a hot cathode discharge tube or an electron tube such as a vacuum tube.

In accordance with the present invention, the auxiliary linear members are fixed to the same fixing member or the separated fixing members prepared on the same substrate, so that the installation space thereof can be smaller and the fixing process can be simplified. Further, fewer fixing members of the auxiliary linear members are needed. The reduction in the number of the wirings for the auxiliary linear member and the terminals for extracting the wirings can be obtained.

In the present invention, one or more pairs of corresponding dampers symmetrically arranged above and below the linear member such as the filament are fixed to the same or the separate fixing member(s) formed on any one of the front substrate and the anode substrate so that the installation space of the auxiliary linear members can be reduced and the fixing process can be simplified. Further, the number of the fixing members is reduced together with the number of the wirings of the dampers and terminals for extracting the wirings.

Further, the dampers symmetrically disposed above and below the linear member such as the filament can be fixed to the same substrate and, further, both dampers are fixed to the same spacer pad. In this case, one spacer pad can be used for the pair of dampers and perform double duty as the fixing member or the spacer. Accordingly, the space for fixing the dampers can be smaller, thereby realizing a small size of a fluorescent radiation device. Moreover, the dampers can be fixed to the same substrate so that the fixing process can be facilitated. One spacer pad can be used for both dampers and can serve a dual function as the fixing member or the spacer with the results that: fewer spacers or fixing members of the dampers are needed and, accordingly, fewer metal layers for fixing same are used; and the processes including the fixing process of the spacers or fixing members and the manufacturing process of the metal layers can be reduced.

Since the end of the damper is joined to the step-shaped fixing portion along the bottom portion and the vertical portion thereof, the damper can have sufficient amount of portion joined to the spacer pad to thereby heighten the binding strength. Further, by forming the fixing portions at different locations in the spacer pad, there can be formed in the spacer pad a plurality of spacers with different heights.

In case of connecting the wiring to the damper, the wiring can be used for a pair of corresponding dampers and, therefore, it is unnecessary to increase the number of the wirings and the terminals for extracting the wirings.

In accordance with the present invention, the dampers and the spacer pads are fixed by using the ultrasonic bonding technique, which does not generate heat during the fixing process, compared with the case of the other technique (e.g., welding technique). Accordingly, damages to neighboring components due to the heat can be prevented.