JP4713023B2 - Fluorescent display tube - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a fluorescent display tube in which an elastically deformable filament anchor that applies tension to a filament is fixed to a frame.
[0002]
[Prior art]
In this type of fluorescent display tube, a direct heat cathode is usually used, and the so-called ternary oxidation of barium oxide, calcium oxide, and strontium oxide is directly applied to the filament formed by the tungsten serving as the cathode. An electron-emitting substance made of a material is applied. When the fluorescent display tube is in operation, the filament is kept at 600-650 ° C. to emit thermionic electrons from the surface of the filament. Accordingly, the filament is expanded and lengthened as compared with the case where the fluorescent display tube is not operated. Therefore, a spring having an appropriate tension and stroke is required at the end of the filament so that the filament does not bend.
[0003]
That is, one end of the filament is fixed by a filament support, and the other end is supported by a support member called a filament anchor formed by a spring material. The filament anchor is provided with an elastically deformable filament support portion. With the filament support portion elastically deformed, the other end of the filament is welded to a welding tab formed on the upper end of the filament support portion. The tension is given to. The filament anchor and the filament support are fixed on the frame by spot welding.
[0004]
[Problems to be solved by the invention]
In the conventional fluorescent display tube described above, if the frame is deformed due to insufficient strength of the frame to which the filament anchor or the filament support is fixed, the frame thickness is increased or the frame width is increased. It was only possible to expand. However, since the frame is sandwiched between the anode substrate and the face glass, if the thickness of the frame is increased, the gap between the sandwiched portions is increased, causing a vacuum failure in the fluorescent display tube. .
[0005]
Also, when expanding the width of the frame due to restrictions on the external dimensions of the fluorescent display tube and the display area of the display surface, the distance between this frame and the grid, the distance between the exhaust pipes, or the distance to the short side face glass There was a problem that could not be secured. Therefore, if the thickness of the frame cannot be increased or the width of the frame cannot be increased due to the structural limitations of these fluorescent display tubes, the frame cannot be reinforced and vibrations occur in the filament. There was a problem that the filament was easily broken.
[0006]
Also, a plurality of filament anchor support portions are provided corresponding to the plurality of filaments, and when fixing the filament anchor to the frame, welding is performed for each part corresponding to the plurality of filament support portions. There is a need to do. In this case, if the welding position is shifted, the filament anchor is fixed without being brought into close contact with the frame, so that the filament anchor is lifted. Therefore, there is a problem that the filament tension cannot be kept constant. In addition, the filament anchor has a plurality of positioning holes for the frame, and when welding, it is necessary to avoid these holes. As a result, the welding work area becomes extremely narrow, so that welding defects are reduced. There was also a problem that occurred.
[0007]
The present invention has been made in view of the above-described conventional problems, and a first object is to reinforce the frame and prevent the filament from being disconnected. The second purpose is to keep the tension of the filament constant. A third object is to improve the quality of welding, thereby improving productivity.
[0008]
[Means for Solving the Problems]
In order to achieve this object, the invention according to claim 1 includes an anode provided on an anode substrate and coated with a phosphor, and a plurality of filaments arranged opposite to the anode, and the filaments are fixed to a frame. A plurality of filament support portions that are stretched between the two support members, and at least one of the two support members is elastically deformable to apply tension to each of the plurality of filaments, and A plurality of filament support portions are connected to each other, and the connection portions are clamped and fixed between a press plate and a frame having substantially the same shape as the connection portions, and two pieces are attached to both ends of the press plate. A positioning hole is provided .
Therefore, the presser plate adheres uniformly to the entire connecting portion of the anchor.
[0009]
The invention according to claim 2 is the invention according to claim 1, wherein an oxide film is formed on a surface of the presser plate .
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is an exploded perspective view showing a fluorescent display tube according to the present invention. FIG. 2 is a perspective view of the overall appearance, with a part broken away. 3 is a cross-sectional view taken along line III-III in FIG. FIG. 4 is a perspective view showing the main part in an exploded manner. FIG. 5 is an enlarged cross-sectional view of the main part.
In FIG. 1, what is generally indicated by reference numeral 1 is a segment-type fluorescent display tube having a triode structure, and is formed by integrating an anode assembly 2, a frame assembly 4, and a face glass 6. The
[0011]
As shown in FIG. 3, the anode assembly 2 is provided with an anode substrate 21 made of soda glass or the like, and the anode substrate 21 is electrically connected by thick film printing using carbon paste or the like. A wiring 22 and a terminal portion 23 are formed. An insulating layer 24 is formed on the anode substrate 21 to cover the conductive connection wiring 22 using an insulating paste. On this insulating layer 24, an anode 25 arranged in a seven-segment shape is formed by thick film printing using Ag paste, and this anode 25 is a through hole formed in the insulating layer 24. Is electrically connected to the conductive connection wiring 22. On the anode 25, a phosphor 26 is applied by electrodeposition by electrophoresis or thick film printing, and an anode 27 is formed.
[0012]
Reference numeral 30 denotes a grid, which is formed by meshing a stainless ultra-thin plate by photo-etching. As shown in FIG. 3, both end portions are bent into a cross-sectional crank shape, and leg portions 31, 31 are provided. ing.
[0013]
As shown in FIG. 1, the frame assembly 4 includes a thin frame 40 made of a metal material having a thermal expansion coefficient similar to that of the anode substrate 21 and the face glass 6, for example, a 426 alloy (Fe—Ni—Cr alloy). Is provided. The frame 40 is substantially U-shaped in plan view with the cathode lead external lead-out support plates 42 and 43 provided so as to face the connecting portion 41, and these cathode lead external lead-out support plates 42 and 43. 43 is formed in a frame shape by a wire 44 and a frame 40 connecting the open end portions of the respective 43.
[0014]
Filament terminals 45 and 46 are provided at the ends of the cathode lead external lead-out support plates 42 and 43 on the connecting portion 41 side, and are connected between the filament terminals 45 and 46 so as to be connected. A plurality of signal / power terminals 47 project from the portion 41. The filament terminals 45 and 46 and the signal / power terminal 47 are formed integrally with the frame 40 by removing unnecessary portions of the frame 40 by a chemical etching method. The frame 40 has an oxide film formed on the surface thereof by performing an oxidation process 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 on one cathode lead external lead-out support plate 43 by spot welding.
[0015]
Next, a fixing structure of a filament anchor as a support member that supports one end of the filament, which is a feature of the present invention, will be described with reference to FIGS.
In FIG. 4, reference numeral 50 denotes a filament anchor formed of an extremely thin plate-like spring material having extremely small elasticity, and includes a connecting portion 51 formed in a flat plate shape and a plan view from one side end of the connecting portion 51. 4 arm portions 52 as elastically deformable filament support portions that are inclined and projecting obliquely upward in a side view, and tabs 53 formed at respective tips of the four arm portions 52. And is composed of. The connecting portion 51 is provided with four positioning holes 51 b corresponding to the four arm portions 52.
[0016]
The cathode lead external lead-out support plate 42 is provided with four positioning holes 42a corresponding to the four positioning holes 51a of the filament anchor 50, and at the side end of the filament anchor 50. Corresponding to the four arm portions 52, four saw blade-shaped notches 42b are formed.
[0017]
Reference numeral 55 denotes a presser plate which is formed in substantially the same outer shape as the connecting portion 51 of the filament anchor 50 in a plan view, is formed to have a thickness substantially the same as the thickness of the cathode lead external lead-out support plate 42, and two are provided at both ends. Positioning holes 55a, 55a are provided. In this manner, the presser plate 55 is formed to have a thickness substantially the same as the thickness of the cathode lead external lead-out support plate 42, so that it is larger than the thickness of the connecting portion 51 of the filament anchor 50 as shown in FIG. 5. The rigidity is larger than that of the connecting portion 51. The holding plate 55 is formed of the same 426 alloy as the cathode lead external lead-out support plates 51 and 52, and an oxidation film is formed on the surface by performing an oxidation treatment in the atmosphere.
[0018]
In such a configuration, in order to fix the filament anchor 50 to the cathode lead external lead-out support plate 42, the connecting portion 51 between the presser plate 55 and the filament anchor 50 is inserted through the positioning holes 42a, 51a, 55a. The cathode lead external lead-out support plate 42 is positioned at a predetermined position and laminated as shown in FIG. Since the laminated presser 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 of the cathode lead with the entire surface of the connecting portion 51 covered with the presser plate 55. The support plate 42 and the presser plate 55 are sandwiched. As shown by a point A in FIG. 4, the filament anchor 50 is fixed to the cathode lead external lead-out support plate 42 by spot welding at two locations.
[0019]
One end of the filament denoted by reference numeral 58 is attached to the filament support 48 by welding, and the other end is welded to the tab 53 in a state where the arm portion 52 of the filament anchor 50 is elastically deformed. And the filament support 48 in a state where 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.
[0020]
As shown in FIG. 1, the face glass 6 includes a plate-shaped front glass 61 and a frame-shaped spacer glass 62, and forms a vacuum container together with the anode substrate 21. The spacer glass 62 is formed of the same glass material as that of the front glass 61, and is fused to the lower surface of the front glass 61 via a low melting point glass 63 (see FIG. 3). An exhaust pipe 64 is bonded to the part via low-melting glass.
[0021]
To assemble the fluorescent display tube 1 in such a configuration, four grids 30 are placed on the anode substrate 21 corresponding to each anode 27 of the anode substrate 21 as shown in FIG. A conductive paste is applied on the anode substrate 21 in advance, and the grid 30 is fixed on the anode substrate 21 by adhering the legs 31 and 31 of the grid 30 to the conductive paste, and drying and firing. Next, the frame assembly 4 is placed at a predetermined position on the anode substrate 21, and the signal / power 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 disposed above the anode 3 so as to face the anode 3.
[0022]
Thereafter, a low melting point glass as a non-conductive adhesive is bonded to the joint portion of the face glass 6, the anode substrate 21 and the frame 40 so that the frame 40 is sandwiched between the lower end of the spacer glass 62 of the face glass 6 and the anode substrate 21. (Frit glass) 65 is applied and laminated. After these are sandwiched between sealing clips, they are loaded into a heating furnace and the low melting point glass 65 is heated and fired, whereby the face glass 6, the anode substrate 21 and the frame 40 are integrally joined to form a vacuum container. Next, the vacuum vessel is taken out from the heating furnace, and unnecessary portions of the frame 40 protruding on both sides thereof are cut and removed along the cutting line 70.
[0023]
Next, after the vacuum container is evacuated by heating the vacuum container and exhausting the air in the vacuum container to the outside through the exhaust pipe 64, the exhaust pipe 64 is cut and the cut portion is closed to cut off the sealing. To do. Thereafter, the getter ring 49 is flushed from outside the vacuum vessel by high frequency induction heating, and a metal barium film is deposited on a part of the vacuum vessel, so that the occluded gas in the vacuum vessel is adsorbed and sufficient for electron emission. Increase the degree of vacuum. The presser plate 55 and the cathode lead external lead-out support plate 42 are thermally expanded by the heat generated during the getter flash, and both the presser plate 55 and the cathode lead external lead-out support plate 42 are made of the same 426 alloy. Thus, it is possible to prevent the filament anchor 50 from being deformed or damaged due to thermal expansion.
[0024]
In the fluorescent display tube 1 thus formed, the connecting portion 51 of the filament anchor 50 is formed with an oxide film on the surface and covered with the presser plate 55, so that the oxide film can transmit light in the connecting portion 51. Reflection can be suppressed. For this reason, light incident from the outside of the fluorescent display tube 1 and light from the anode 27 adjacent to the filament anchor 50 are not reflected by the connecting portion 51, so that the display quality is deteriorated by the reflected light. There is nothing.
[0025]
Further, since the presser plate 55 is formed in substantially the same shape as the connecting portion 51 of the filament anchor 50 in a plan view, the entire surface of the connecting portion 51 is in close contact with the cathode lead external lead-out support plate 42 by the presser plate 55. It is fixed with. In addition, the presser plate 55 is formed to be more rigid than the connecting portion 51 of the filament anchor 50. Therefore, even if the position of the welding point A of the presser plate 55 is slightly deviated, the connecting portion 51 does not lift from the cathode lead external lead-out support plate 42, so that the tension of the filament 58 applied by the arm portion 52 is constant. Since the presser plate 55 can be fixed by spot welding at least at two locations, the number of welded locations can be reduced.
[0026]
Further, not only can the number of welding points be reduced, but the press plate 55 is provided with only a minimum of two positioning holes 55a, so that the welding work area on the surface of the press plate 55 is not reduced. Occurrence of poor welding can also be suppressed, and the productivity can be improved because welding work can be performed easily and reliably.
[0027]
Further, the holding plate 55 is fixed to the cathode lead external lead-out support plate 42 via the connecting portion 51, whereby the cathode lead external lead-out support plate 42 is reinforced in strength by the press plate 55. Therefore, not only the deformation of the cathode lead outside lead-out support plate 42 can be prevented, but also the vibration of the cathode lead outside lead-out support plate 42 can be reduced, so that the filament 58 can be prevented from being disconnected.
[0028]
In the first embodiment, the filament anchor 50 is fixed to the upper surface of the cathode lead external lead-out support plate 42. However, the cathode lead external lead-out support plate 42 may simply be reinforced by the holding plate 55. For example, the filament anchor 50 may be fixed to the lower surface of the cathode lead external lead-out support plate 42. In that case, the arm portion 52 of the filament anchor 50 is fixed so as to face the notch 42 b of the cathode lead external lead-out support plate 42.
[0029]
FIG. 6 is a cross-sectional view of a main part showing a second embodiment of the present invention.
In the second embodiment, when it is desired to increase the distance between the filament 58 and the anode substrate 21 from H1 to H2, the holding plate 55 is connected to the connecting portion 51 of the filament anchor 50 and the cathode lead external lead-out support plate 42. The presser plate 55, the connecting portion 51, the presser 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 presser plate 55 is determined by the amount by which the interval between the filament 58 and the anode substrate 21 is increased, that is, (H2−H1). Thus, even when the interval between the filament 58 and the anode substrate 21 is increased, the same filament anchor 50 can be used, 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, even if the distance between the filament 58 and the anode substrate 21 changes, the tension of the filament 58 can be kept constant.
[0030]
In this second embodiment, the presser 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 presser plate 55 has the same thickness t as the presser plate 55. In this case, by preparing spacers having various thicknesses, various spaces between the filament 58 and the anode substrate 21 can be dealt with.
[0031]
【Example】
The thickness of the holding plate 55 was 0.15 to 0.3 mm, and the oxidation treatment with the atmosphere was performed at about 500 ° C.
[0032]
In the first and second embodiments, one end of the filament 58 is supported by the filament support 48. However, both ends of the filament 58 may be supported by a pair of filament anchors 50 and 50.
[0033]
【The invention's effect】
As described above, according to the first aspect of the present invention, not only is the deformation of the cathode lead external lead-out support plate prevented, but also the vibration of the cathode lead external lead support plate can be reduced. Can also be prevented. Further, since the anchor can be prevented from floating, the tension of the filament can be kept constant. Furthermore, the occurrence of welding defects can be suppressed, and the welding operation can be performed easily and reliably, so that productivity is improved.
[Brief description of the drawings]
FIG. 1 is an exploded perspective view showing a fluorescent display tube according to the present invention.
FIG. 2 is an overall perspective view of the fluorescent display tube according to the present invention, with a part thereof broken away.
FIG. 3 is a cross-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 an enlarged cross-sectional view showing a main part 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 support plate, 45, 46 ... Filament terminal, 47 ... Signal / power supply terminal, 48 ... Filament support, 50 ... Filament anchor, 51 ... Connection part, 52 ... Arm part, 53 ... Tab, 55 ... presser plate, 58 ... filament, 61 ... windshield, 62 ... spacer glass.

Claims (2)

An anode provided on an anode substrate and coated with a phosphor, and a plurality of filaments arranged opposite to the anode, the filaments being stretched between two support members fixed to a frame, At least one support member among the support members is formed by a plurality of elastically deformable filament support portions that apply tension to each of the plurality of filaments, and a connection portion that connects the plurality of filament support portions. A fluorescent display tube characterized in that a connecting portion is sandwiched and fixed between a holding plate and a frame having substantially the same shape as the connecting portion, and two positioning holes are provided at both ends of the holding plate. In the fluorescent display tube of claim 1, wherein a fluorescent display tube, characterized in that the oxide film is formed on the surface of the pressing plate.

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