JP2003031168A - Anchor fixing structure for luminescent display tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the breaking of filament and to constantly keep the tension of the filament by reducing the number of welding points. SOLUTION: The filament anchor 50 is composed of a plurality of elastically deformable arm parts 52 supporting one end of filaments 58 and a joint part 51 jointing arm parts 52. The joint part 51 is interposed between a pressing board 55 having same shape with the joint part 51 and a supporting board 42 for guiding negative electrode leads outsides, and fixed by spot welding.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an anchor fixing structure in a fluorescent display tube for fixing an elastically deformable filament anchor for applying tension to a filament to a frame.

[0002]

2. Description of the Related Art In this type of fluorescent display tube, a direct heating type cathode is usually used, and barium oxide, calcium oxide, strontium oxide is directly formed on a filament formed by tungsten as the cathode in an ultrafine wire. The so-called ternary oxide is used as the electron emissive material. When the fluorescent display is in operation, the filament is kept at 600-650 ° C. to emit thermoelectrons from the surface of the filament. Therefore, the filament is expanded and lengthened compared to when the fluorescent display tube is not operating. Therefore, in order to prevent the filament from bending, a spring having appropriate tension and stroke is required at the end of the filament.

That is, one end of the filament is fixed by a filament support, and the other end is supported by a supporting member called a filament anchor formed of a spring material. The filament anchor is provided with an elastically deformable filament support part.The elastically deformed filament support part is welded to the welding tab formed on the upper end of the filament support part at the other end of the filament to form a filament. Tension is applied to. The filament anchor and the filament support are fixed on the frame by spot welding.

[0004]

In the anchor fixing structure of the conventional fluorescent display tube described above, when deformation of the frame occurs due to insufficient strength of the frame fixing the filament anchor or the filament support. Could only deal with increasing the plate thickness of the frame or expanding the width of the frame. However, since the frame is structured to be sandwiched between the anode substrate and the face glass, if the plate thickness of the frame is increased, the gap between the sandwiched portions becomes large, which causes a vacuum degree defect in the fluorescent display tube. .

Further, when the width of the frame is expanded due to the external dimensions of the fluorescent display tube and the display area of the display surface, the distance between the frame and the grid, the distance between the exhaust tubes, or the short side face glass. There was a problem that the distance to could not be secured. Therefore, if the plate thickness of the frame cannot be increased or the width of the frame cannot be expanded due to the structural restrictions of these fluorescent display tubes, the frame cannot be reinforced, and the filament vibrates. There is a problem that the filament is easily broken and the filament is broken.

In addition, corresponding to a plurality of filaments,
A plurality of filament support parts of the filament anchor are also provided, and when fixing the filament anchor to the frame, it is necessary to perform welding at each part corresponding to the plurality of filament support parts. In this case, if the welding position shifts, the filament anchor is fixed without being brought into close contact with the frame, that is, so-called floating of the filament anchor occurs, and there is also a problem that the filament tension cannot be kept constant. In addition, the filament anchor is provided with a plurality of positioning holes for the frame, and when welding, it is necessary to avoid these holes, and as a result, the welding work area becomes extremely narrow, which results in poor welding. There was also a problem that it would occur.

The present invention has been made in view of the conventional problems described above, and a first object thereof is to reinforce the frame and prevent the filament from breaking. The second purpose is to keep the tension of the filament constant. Also,
The third purpose is to improve the quality of welding and thus the productivity.

[0008]

In order to achieve this object, the invention according to claim 1 comprises: an anode provided on an anode substrate and coated with a phosphor; and a plurality of filaments arranged to face the anode. And stretching these filaments between two supporting members fixed to a frame,
At least one support member of the plurality of support members is formed by a plurality of elastically deformable filament support parts that apply tension to each of the plurality of filaments and a connection part that connects these plurality of filament support parts. The connecting portion is sandwiched and fixed between a holding plate having substantially the same shape as the connecting portion and the frame. Therefore, the holding plate is evenly attached to the entire connecting portion of the anchor.

The invention according to claim 2 is the invention according to claim 1, wherein a spacer is interposed between the connecting portion of the anchor and the frame. Therefore, the same anchor can change the distance between the filament and the anode substrate.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an exploded perspective view of a fluorescent display tube according to the present invention. FIG. 2 is a perspective view of the entire appearance of the same, with a part thereof broken away. FIG. 3 shows III- in FIG.
It is a sectional view taken along line III. FIG. 4 is a perspective view showing the same main part in a disassembled and enlarged manner. FIG. 5 is a sectional view showing an enlarged main part of the same. In FIG. 1, reference numeral 1 as a whole is a segment type fluorescent display tube having a triode structure,
It is formed by integrating the anode assembly 2, the frame assembly 4, and the face glass 6.

As shown in FIG. 3, the anode assembly 2 is provided with an anode substrate 21 made of soda glass or the like.
A thick film is printed on the anode substrate 21 using a carbon paste or the like to form the conductive connection wiring 22 and the terminal portion 2.
And 3 are formed. In addition, on the anode substrate 21, an insulating layer 2 that covers the conductive connection wiring 22 with an insulating paste is used.
4 are formed. On this insulating layer 24, an anode 25 arranged in a 7-segment day shape is formed by thick film printing using Ag paste.
5 is electrically connected to the conductive connection wiring 22 through a through hole formed in the insulating layer 24. This anode 2
A phosphor 26 is applied on the electrode 5 by electrophoretic deposition or thick film printing to form an anode 27.

Reference numeral 30 denotes a grid, which is formed by etching a stainless steel ultra-thin plate into a mesh shape. As shown in FIG. 3, both ends thereof are bent to have a crank shape in cross section, and leg portions 31, 31 are formed. Is provided.

As shown in FIG. 1, the frame assembly 4 has a coefficient of thermal expansion of the anode substrate 21 and the face glass 6.
To a metal material similar to, for example, a 426 alloy (Fe-Ni-
A thin plate-shaped frame 40 made of Cr alloy) is provided. The frame 40 includes a support plate 42 for leading out the cathode lead, which is provided so as to face the connecting portion 41.
43 has a substantially U-shape in a plan view, and is formed in a frame shape by a wire rod 44 and a frame 40 connecting the open ends of the cathode lead external lead-out support plates 42, 43.

Support plates 42 for leading out the cathode leads to the outside,
Filament terminals 45 and 46 are provided at the end portions of the connecting portion 41 side of 43, respectively.
A plurality of signal / power supply terminals 47 are projectingly provided on the connecting portion 41 so as to be arranged between the terminals 5 and 46. The filament terminals 45 and 46 and the signal / power supply terminal 47 are formed integrally with the frame 40 by removing unnecessary portions of the frame 40 by a chemical etching method.
An oxide film is formed on the surface of the frame 40 by performing an oxidation treatment in the atmosphere. Reference numeral 48 denotes four filament supports, and 49 denotes a getter ring. The filament support 48 and the getter ring 49 are fixed to one of the cathode lead external lead-out support plates 43 by spot welding.

Next, the fixing structure of the filament anchor as a support member for supporting one end of the filament, which is a feature of the present invention, will be described with reference to FIGS. 4 and 5. In FIG. 4, reference numeral 50 denotes a filament anchor formed of a spring material having an extremely small elasticity in the form of an ultra-thin plate, and a connecting portion 51 formed in a flat plate shape and a plan view from one side end of the connecting portion 51. , And four arm portions 52 as elastically deformable filament support portions that are provided to project obliquely upward in a side view, and tabs 53 formed at the respective tips of these four arm portions 52. It is composed of and. The connecting portion 51 is provided with four positioning holes 51b corresponding to the four arm portions 52.

The cathode lead external lead-out support plate 42 has four positioning holes 51 for the filament anchor 50.
Four positioning holes 42a are provided corresponding to a, and at the side end, four positioning holes 42a of the filament anchor 50 are provided.
Corresponding to each arm 52, four sawtooth notches 42b
Are formed.

Reference numeral 55 denotes a holding plate, which is formed to have substantially the same outer shape as the connecting portion 51 of the filament anchor 50 in a plan view, is formed to have substantially the same thickness as the cathode lead external lead-out supporting plate 42, and has both end portions. 2 positioning holes 5
5a and 55a are provided. In this way, the holding plate 5
Since 5 is formed to have substantially the same thickness as that of the cathode lead external lead-out support plate 42, it is formed to be larger than the thickness of the connecting portion 51 of the filament anchor 50 as shown in FIG. Is also formed with high rigidity. The holding plate 55 is made of the same 426 alloy as the cathode lead external lead-out support plates 51 and 52, and an oxide film is formed on the surface by performing an oxidation treatment in the atmosphere.

In this structure, in order to fix the filament anchor 50 to the cathode lead external lead-out support plate 42, respective positioning holes 42a, 51a, 55 are provided.
The connecting portion 51 between the pressing plate 55 and the filament anchor 50 is positioned at a predetermined position with respect to the cathode lead external lead-out support plate 42 via a, and they are laminated as shown in FIG. Since the stacked pressing plate 55 has substantially the same outer shape as the connecting portion 51, the connecting portion 51 of the filament anchor 50 is led out to the outside of the cathode lead in a state where the entire surface of the connecting portion 51 is covered with the pressing plate 55. Support plate 42 and presser plate 55
Sandwiched between. As shown by the point A in FIG. 4, the filament anchor 5 is formed by spot welding at two points.
0 is fixed to the support plate 42 for leading out the cathode lead to the outside.

By attaching one end of the filament indicated by reference numeral 58 to the filament support 48 by welding and welding the other end to the tab 53 in a state where the arm portion 52 of the filament anchor 50 is elastically deformed, the filament 58 is formed. The filament anchor 50 and the filament support 48 are stretched while tension is applied. The arm portion 52 of the filament anchor 50 that applies tension to the filament anchor 50 is positioned so as to be inclined with respect to the extending direction of the filament 58.

As shown in FIG. 1, the face glass 6 is
A plate-shaped windshield 61 and a frame-shaped spacer glass 6
2 and forms a vacuum container together with the anode substrate 21. The spacer glass 62 is made of the same glass material as the windshield 61, and has a low melting point glass 63 (see FIG. 3) on the lower surface of the windshield 61.
The exhaust pipe 64 is adhered to a part of the peripheral surface of the spacer glass 62 via the low melting point glass.

In order to assemble the fluorescent display tube 1 having such a structure, as shown in FIG. 1, four grids 30 corresponding to the respective anodes 27 of the anode substrate 21 are placed on the anode substrate 21. . A conductive paste is previously applied on the anode substrate 21, and the grids 30 are fixed on the anode substrate 21 by bonding the leg portions 31 and 31 of the grid 30 to these conductive pastes and drying and firing.
Next, the frame assembly 4 is placed at a predetermined position on the anode substrate 21, and the signal / power supply terminal 47 and the terminal portion 23 of the anode substrate 21 are electrically connected via a conductive paste. In this state, the four filaments 58 stretched between the filament anchor 50 and the filament support 48 are
It is arranged above the anode 3 so as to face the anode 3.

Thereafter, the lower end of the spacer glass 62 of the face glass 6 and the anode substrate 21 are sandwiched between the frame 40 and the joint portion of the face glass 6, the anode substrate 21 and the frame 40 as a non-conductive adhesive. A low melting point glass (frit glass) 65 is applied and these are laminated. After sandwiching these with a sealing clip, the face glass 6, the anode substrate 21, and the frame 40 are integrally joined to form a vacuum container by loading in a heating furnace and heating and baking the low melting point glass 65. Next, take out the vacuum container from the heating furnace and project the frame 40 on both sides.
The unnecessary portion of is cut and removed along the cutting line 70.

Then, while the vacuum container is being heated, the air in the vacuum container is exhausted to the outside through the exhaust pipe 64 to evacuate the inside of the vacuum container, and then the exhaust pipe 64 is cut to close the cutting portion. Cut off the seal. After that, the getter ring 49 is flushed from the outside of the vacuum container by high-frequency induction heating, and a metal barium film is vapor-deposited on a part of the inside of the vacuum container. Increase the degree of vacuum up to. The pressing plate 55 and the cathode lead external lead-out supporting plate 42 are thermally expanded by the heat generated during the getter flash. Both the pressing plate 55 and the cathode lead external lead-out supporting plate 42 are made of the same 426 alloy. This can prevent the filament anchor 50 from being deformed or damaged due to thermal expansion.

In the thus-formed fluorescent display tube 1, since the connecting portion 51 of the filament anchor 50 has an oxide film formed on its surface and is covered with the holding plate 55, the connecting portion 51 is formed by this oxide film. It is possible to suppress the reflection of light in. Therefore, the fluorescent display tube 1
Since the light incident from the outside and the light from the anode 27 adjacent to the filament anchor 50 are not reflected by the connecting portion 51, the display quality is not deteriorated by the reflected light.

Further, since the holding plate 55 is formed to have substantially the same shape as the connecting portion 51 of the filament anchor 50 in plan view, the entire surface of the connecting portion 51 becomes the cathode lead external lead-out support plate 42 by the holding plate 55. It is fixed in close contact. Moreover, the holding plate 55 is formed to have a rigidity higher than that of the connecting portion 51 of the filament anchor 50. Therefore, even if the position of the welding point A of the pressing plate 55 is slightly displaced, the connecting portion 51 does not float up from the cathode lead external lead-out supporting plate 42, so that the tension of the filament 58 applied by the arm portion 52 is constant. Can be maintained and the holding plate 55 can be fixed by spot welding at least at two points, so that the number of welding points can be reduced.

Further, not only the number of welded portions can be reduced, but also the holding plate 55 is provided with only two positioning holes 55a, so that the holding plate 55 is minimized.
Since the welding work area on the surface does not become narrow, the occurrence of welding defects can be suppressed, and the welding work can be performed easily and reliably, so that the productivity is improved.

Further, since the holding plate 55 is fixed to the cathode lead external lead-out support plate 42 via the connecting portion 51, the cathode lead external lead-out support plate 42 is reinforced by the holding plate 55 in terms of strength. Therefore, not only the deformation of the cathode lead external lead-out support plate 42 can be prevented but also the vibration of the cathode lead external lead-out support plate 42 can be reduced.
It is also possible to prevent disconnection of the filament 58.

In the first embodiment,
Although the filament anchor 50 is fixed on the upper surface of the cathode lead external lead-out support plate 42, if the support plate 42 for cathode lead external lead-out is simply reinforced by the holding plate 55, the filament anchor 50 is supported for cathode lead external lead-out support. It may be fixed to the lower surface of the plate 42. In that case, the arm portion 52 of the filament anchor 50 is fixed so as to face the notch 42b of the cathode lead external lead-out support plate 42.

FIG. 6 is a sectional view of the essential parts showing a second embodiment of the present invention. In the second embodiment,
The distance between the filament 58 and the anode substrate 21 is changed from H1 to H.
In order to expand to 2, the holding plate 55 is connected to the connecting portion 51 of the filament anchor 50 and the supporting plate 42 for leading out the cathode lead.
The holding plate 55, the connecting portion 51, the holding plate 55, and the cathode lead external lead-out support plate 42 are simultaneously fixed by spot welding. In other words, the thickness t of the pressing plate 55 is the amount by which the distance between the filament 58 and the anode substrate 21 is increased, that is, (H2-H1).
Will be decided by. As described above, the same filament anchor 50 can be used even when the distance between the filament 58 and the anode substrate 21 is widened, so that the number of parts can be reduced. Further, since the entire length of the arm portion 52 of the filament anchor 50 can be made the same length, the tension of the filament 58 can be kept constant even if the distance between the filament 58 and the anode substrate 21 changes.

In the second embodiment, the holding plate 55 is interposed between the connecting portion 51 of the filament anchor 50 and the cathode lead external lead-out support plate 42. However, the holding plate 55 has the same thickness. Spacers formed at t may be used, and in that case, various spacings between the filament 58 and the anode substrate 21 can be dealt with by preparing spacers of various thicknesses.

[0031]

Example The thickness of the holding plate 55 was 0.15 to 0.3 mm, and the oxidation treatment in the atmosphere was performed at about 500 ° C.

In the first and second embodiments of the present invention, one end of the filament 58 is supported by the filament support 48, but both ends of the filament 58 may be supported by the pair of filament anchors 50, 50.

[0033]

As described above, according to the first aspect of the invention, not only the deformation of the support plate for leading out the cathode lead but also the vibration of the support plate for leading out the cathode lead can be reduced. Therefore, it is possible to prevent the filament from breaking. Further, since the floating of the anchor can be prevented, the tension of the filament can be kept constant. In addition, the occurrence of welding defects can be suppressed, and welding work can be performed easily and reliably, so that productivity is improved.

According to the second aspect of the invention, the same anchor can be used even if the distance between the filament and the anode is changed, so that the tension of the filament can be kept constant.

[Brief description of drawings]

FIG. 1 is an exploded perspective view of a fluorescent display tube according to the present invention.

FIG. 2 is an overall external perspective view showing a fluorescent display tube according to the present invention with a part thereof broken away.

3 is a sectional view taken along line III-III in FIG.

FIG. 4 is an exploded perspective view showing an enlarged main part of a fluorescent display tube according to the present invention.

FIG. 5 is an enlarged cross-sectional view showing a main part of a fluorescent display tube according to the present invention.

FIG. 6 is a sectional view of an essential part showing an enlarged view of a second embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Fluorescent display tube, 2 ... Anode assembly, 4 ... Frame assembly, 6 ... Face glass, 21 ... Anode substrate, 25 ... Anode, 26 ... Fluorescent paint, 27 ... Anode, 30 ... Grid, 40 ... Frame, 42 , 43 ... Cathode lead external lead-out support plate, 45, 46 ... Filament terminal, 47 ... Signal / power terminal, 48 ... Filament support, 50 ... Filament anchor, 51 ... Connection part, 52 ... Arm part, 53 ...
Tabs, 55 ... Holding plate, 58 ... Filament, 61 ... Windshield, 62 ... Spacer glass.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Michiru Seko             700 Wada, Ueno Town, Ise City, Mie Prefecture Ise             Electronic Industry Co., Ltd. F term (reference) 5C027 BB03                 5C036 EE14 EF02 EF05 EG13 EH04                       EH08

Claims (2)

[Claims] 1. An anode substrate is provided with an anode coated with a phosphor, and a plurality of filaments arranged to face the anode. These filaments are stretched between two supporting members fixed to a frame. A plurality of elastically deformable filament supporting portions that apply tension to each of the plurality of filaments, and a connecting portion that connects the plurality of filament supporting portions to at least one of the two supporting members. An anchor fixing structure in a fluorescent display tube, characterized in that the connecting portion is formed by and the connecting portion is sandwiched and fixed between a holding plate having substantially the same shape as the connecting portion and the frame. 2. The anchor fixing structure for a fluorescent display tube according to claim 1, wherein a spacer is interposed between the connecting portion of the supporting member and the frame.