JP3418327B2 - Fluorescent display tube - Google Patents

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 in which a mesh grid electrode and a rib grid electrode are provided in an overlapping manner and can be driven in a grid multi-matrix system.

[0002]

2. Description of the Related Art A phosphor layer is fixed on a plurality of anodes provided on a substrate in a shape corresponding to a predetermined light emission pattern, and is generated from a cathode installed above the phosphor layer in a vacuum space. There is known a fluorescent display tube of a type that selectively emits light from a predetermined phosphor layer by controlling the generated electrons with a grid electrode provided between the phosphor layer and the cathode. In such a fluorescent display tube, since the surface of the phosphor layer on which the electrons generated from the cathode collide is located on the display side, the operating voltage is low and the display is clear, and phosphors with different emission colors are prepared. As a result, it is possible to perform color display, and is therefore widely used in audio equipment and display parts of display panels of automobiles.

[0003]

As a kind of the above-mentioned fluorescent display tube, for example, a graphic display in which a large number of anodes to which dot-shaped phosphor layers are fixed are arranged in a matrix is known. . In such a fluorescent display tube for graphic display, for the purpose of facilitating high definition or facilitating manufacturing and driving by suppressing an increase in the number of anode wirings, for example, a dynamic matrix such as a multi-matrix system is used. Used in the driving method. Japanese Patent Application Laid-Open No. 8-36975 filed by the applicant of the present application and published earlier
The fluorescent display tube described in the publication is an example of a graphic display driven by a grid multi-matrix system which is one of multi-matrix drive.

The fluorescent display tube described in the above publication is shown in FIG.
As shown in the cross section of the main part, the grid electrodes 22 and 24 are doubly provided for each phosphor layer 12. In the figure, rib-shaped walls 44 are provided upright so as to surround each of the phosphor layers 12, and a rib / grid electrode common to each column of the phosphor layers 12 is provided on the top of the rib-shaped walls 44. 22 is provided, and a mesh grid electrode 24 is provided between the rib grid electrode 22 and the cathode 34, the mesh grid electrode 24 covering the phosphor layer 12 for each predetermined plurality of rows. That is, the rib grid electrode 22 and the mesh grid electrode 24 are substantially overlapped between the phosphor layer 12 and the cathode 34. Therefore, the grid electrode 2
In the direction perpendicular to the cover glass plate 18, which is the viewing surface, although the structure in which the two and 24 are provided in duplicate,
Since one of them, the rib / grid electrode 22, does not block the light emission from the phosphor layer 12, there is an advantage that a sufficiently high brightness can be obtained.

In such a grid-multi-matrix type fluorescent display tube, rib grid electrodes 22 at predetermined positions are connected to common rib grid wirings, respectively, while different rib grid wirings are connected. A mesh grid electrode 24 is provided for each unit of the plurality of connected rib grid electrodes 22. And
In driving, for example, an accelerating voltage is sequentially applied to the mesh grid electrode 24 to perform scanning, and while the accelerating voltage is being applied to each mesh grid electrode 24, a plurality of mesh electrodes located under the mesh grid electrode 24 are positioned. By sequentially applying an accelerating voltage to the rib / grid electrode 22 and scanning, the columns of the phosphor layer 12 to be made to emit light are sequentially selected, and further, in synchronization with the column selection timing, a positive voltage is applied to a desired row of the anodes 42. Is applied to cause the phosphor layer 12 to selectively emit light. Therefore, the rib grid electrode 22 and the mesh grid electrode 24, which are driven independently of each other, must be electrically insulated from each other.

However, the mesh grid electrode 2
4 is fixed to the substrate 14 (generally on the insulating layer 40 provided thereon) by a pair or a plurality of pairs of legs 26, which are provided so as to face each other at two positions on the peripheral portion thereof. However, it is not supported at all in the middle of the legs 26, 26 forming the pair. Therefore, during use of the display tube, due to thermal expansion or the like due to vibration or temperature rise, the mesh portion provided substantially flat so as to cover the phosphor layer 12 is located above or as shown by a dashed line in the drawing. A downwardly convex strain ε occurs. In this case, the rib
The height of each of the grid electrode 22 and the mesh grid electrode 24 is about hr = 200 to 300 (μm), hm = 70.
It is about 0 (μm), and their mutual spacing g is, for example, 400
It is only about ~ 500 (μm). Therefore, when the downward strain ε becomes large, the grid electrodes 22 and 24 may come into contact with each other, so that high reliability of the display tube cannot be obtained.
In order to keep the distance small, the distance between the legs 26, 26 (the distance between the intermediate portions, that is, the erection distance) is limited to, for example, Lm = 20 (mm). When the center interval (dot pitch) of the dot-shaped phosphor layer 12 is about p = 0.5 (mm), the display pattern length that can be secured in the erection direction when the erection distance Lm is about 20 (mm). Ld is 32
Since the size is only about 16 (mm), which is equivalent to a dot, it is desired to further lengthen the display pattern length Ld in order to realize various graphic displays.

If the leg portion 26 of the mesh / grid electrode 24 is raised to increase the mutual distance g between the grid electrodes 22 and 24, the erection distance L is ensured while ensuring the reliability of the display tube.
m can be lengthened. However, the erection distance L
Since the amplitude (strain ε) of the mesh portion increases as m increases, it is necessary to increase the mutual interval g in accordance with the distance Lm in order to prevent mutual contact between the grid electrodes 22 and 24. On the other hand, mesh grid electrode 2
4 is too large [generally 600 (μm) or more] between the ribs and the grid electrode 22, the electrons easily wrap around. The dot pitch p must be increased. Therefore, if the dot pitch p is maintained at about 0.5 (mm) as described above, the leg portion 26 cannot be made so high that the display pattern length Ld cannot be obtained in order to obtain high reliability in a high density pattern arrangement. Cannot be so long. Moreover, the mesh / grid electrode 24 is formed with openings (mesh portions) by etching or the like, and then the leg portions 26 are formed by pressing.
As a result, the leg portions 26 become higher, the separation from the mold is hindered and the workability is significantly reduced.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a grid multi-matrix system capable of ensuring a larger display pattern length in the erection direction of mesh grid electrodes. It is to provide a fluorescent display tube.

[0009]

In order to achieve such an object, the gist of the present invention is that a phosphor layer fixed on each of a plurality of anodes arranged in a matrix on a substrate. And between the phosphor layer and the cathode in order to selectively emit light by controlling the electrons generated from the cathode erected above the phosphor layer in the vacuum space. A plurality of mesh / grid electrodes erected for every predetermined plurality of rows of the phosphor layer, and protruding above the phosphor layers at positions surrounding the phosphor layers below the mesh / grid electrodes. A fluorescent display tube comprising a plurality of rib grid electrodes provided for each row of the phosphor layers on the top of the rib-shaped wall, wherein (a) is provided at a predetermined position on the rib grid electrodes. Electrical insulation It is to include the convex part of.

[0010]

In this way, an electrically insulating convex portion is provided at a predetermined position on the rib grid electrode. Therefore, even if the mesh / grid electrode is distorted during use of the fluorescent display tube, the rib / grid electrode and the mesh / grid electrode are formed by the electrically insulating protrusions provided above the rib / grid electrode. Contact with Therefore, the erection distance of the mesh / grid electrode can be increased while ensuring the electrical insulation between the rib / grid electrode and the mesh / grid electrode, so that the display pattern length in the erection direction determined by the erection distance is further increased. It becomes possible to do.

The electrically insulating convex portion may be provided on the entire surface of the rib / grid electrode so as to cover the entire upper surface thereof. Even in this case, the exposed side surface of the rib / grid electrode forms an electric field for controlling electrons as in the case where no protrusion is provided, and the material and thickness of the protrusion are appropriately adjusted. By defining it, the same electronic control function of the rib / grid electrode can be maintained on the upper surface side as in the conventional case. That is, the "predetermined position on the rib grid electrode" in the claims includes not only a part of the rib grid electrode but the entire surface thereof.

[0012]

Another aspect of the present invention is preferably such that the convex portion is provided at a position apart from a region sandwiched between adjacent ones of the phosphor layers. With this configuration, the convex portion is provided at a position outside the region sandwiched between the phosphor layers adjacent to each other. Therefore, it is further suppressed that the control function of the rib / grid electrode is lowered due to the provision of the electrically insulating convex portion. Incidentally, the control of the electrons flying from the cathode toward the phosphor layers becomes large in the region of the rib / grid electrode sandwiched between the phosphor layers adjacent to each other. In addition, the said area | region respond | corresponds between the corner | angular part of the fluorescent substance layer which adjoins diagonally, when the said fluorescent substance layer is arranged in the vertical direction and the horizontal direction which mutually orthogonally cross.

Further, preferably, the convex portion is provided at a position corresponding to at least a vicinity of a central portion of the mesh / grid electrode in the installation direction. This way, the mesh
The grid electrode has at least the vicinity of the central portion in the erection direction, that is, in the vicinity of the central portion between the supporting portions provided on the peripheral portion of the mesh grid electrode for supporting the portion located on the rib grid electrode. It is supported by the insulating protrusion. Therefore, the convex portion prevents the mesh / grid electrode from being in contact with the rib / grid electrode at the central portion in the erection direction where the strain is the largest, so that the entire mesh / grid electrode is short-circuited with the rib / grid electrode. Is sufficiently suppressed.

Further, preferably, the mesh grid electrode is arranged so as to be substantially in contact with the convex portion. With this configuration, the mesh grid electrode is substantially placed on the rib grid and provided in a state of being substantially in contact with the convex portion. Therefore, when disposing the mesh / grid electrode on the substrate, the height position and parallelism with the substrate can be controlled with high accuracy, and even when the mesh / grid electrode is distorted, the height position can be controlled. Is further suppressed, so that the distance from the cathode is changed due to the distortion, and thus the change in luminance is further suppressed.

Also, preferably, the mesh grid electrode is embedded at an intermediate position in the height direction of the convex portion. With this configuration, the mesh grid electrode is fixedly provided on the rib grid electrode in a state where the mesh grid electrode is embedded at an intermediate position in the height direction of the convex portion. Therefore, when arranging the mesh / grid electrode on the substrate, the height position and parallelism with the substrate can be controlled with high accuracy, and even when the mesh / grid electrode may be distorted Changes in position are substantially prohibited. That is, distortion and vibration of the mesh grid electrode are suppressed not only in the direction approaching the rib grid electrode but also in the direction approaching the cathode. Therefore, it is further suppressed that the distance from the cathode changes due to the distortion, and thus the brightness changes or the life of the fluorescent display tube is shortened. Incidentally, in a fluorescent display tube, the mutual distance between the cathode and the grid electrode (in this application, especially the mesh / grid electrode located on the cathode side) influences the brightness and the life, and when the mutual distance increases, the brightness decreases. , The life will be shortened. According to the above aspect, since the mutual interval is fixed to a substantially constant value, both the brightness change and the life shortening are suppressed as described above.

Preferably, the mesh / grid electrode is supported by being fixed by a conductive fixing material on a base portion having a predetermined height provided on the outer peripheral side of the rib-shaped wall. is there. In this case, the rib-shaped wall is provided with the pedestal having a predetermined height on the outer peripheral side, and the mesh grid electrode is supported by being fixed on the pedestal with the conductive fixing material. Therefore, the mesh / grid electrode can be fixed to the pedestal and at the same time electrically connected to the wiring provided on the substrate through the pedestal. Also, by changing the height of the base, the mesh
It is possible to change the height of the grid electrode, or to reduce the required height of the legs for supporting the mesh grid electrode depending on the height of its pedestal. Furthermore, in the case where the base is provided at a height approximately equal to the height of the mesh / grid electrode, the mesh / grid electrode should be provided at a predetermined height by fixing a flat mesh on the base. As a result, the legs are unnecessary, so that the press forming process for bending and forming the legs of the mesh / grid electrode can be omitted.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described in detail below with reference to the drawings. In the following examples, the dimensional ratios of each part are not necessarily drawn accurately.

FIG. 2 shows a fluorescent display tube 1 according to an embodiment of the present invention.
It is a perspective view which notches and shows a part of 0. In the figure,
The fluorescent display tube 10 includes a substrate 14 made of an insulating material such as glass, ceramics, enamel, etc., which is provided with a large number of dot-shaped fluorescent material layers 12 on one surface thereof, a part of which is shown at the right end of the figure.
A frame-shaped glass spacer 16, a transparent cover glass plate 18, and a plurality of anode terminals 20 _P , mesh grid terminals 20 _MG , rib grid terminals 20 _RG , and cathode terminals. 20 _K, and the substrate 14, the spacer 16, and the cover glass plate 18 are glass-sealed to each other to form a vacuum space surrounded by these members.

The one surface 21 of the substrate 14 covered with the vacuum space functions as a display surface of the fluorescent display tube. As shown in FIG. 3 in which a main part of the display surface 21 is enlarged,
The large number of dot-shaped phosphor layers 12 provided on the display surface 21 are, for example, substantially square (rectangular) each side of which is about 400 (μm), and several tens to several hundreds of columns × They are arranged side by side vertically and horizontally to form a grid of several tens of rows. A plurality of these phosphor layers 12 are provided in common for each unit of a column, the entire circumference of which is arranged in the width direction orthogonal to the longitudinal direction of the substrate 14 and each of which is a column unit. It is surrounded by the rib / grid electrode 22. The rib / grid electrodes 22 are erected on the display surface 21 as will be described later, and each of the ribs / grid electrodes 22 has a ladder shape extending in the width direction, that is, the column direction, that is, a longitudinal shape, and is arranged in the row direction. The display surface 21 in the column direction
Above they are electrically isolated from each other. This rib
The width dimension of the grid electrode 22 is w = 120-at any position of the portion extending in the column direction and the portion extending in the row direction.
It has a uniform size of about 150 (μm), and the center interval of the phosphor layers 12 provided in each row is about p = 500 (μm). Therefore, assuming that the number of phosphor layers 12 in one row surrounded by one rib / grid electrode 22 in the row direction, that is, the number of dots in each row is 48, the display pattern length is L.
It is about d = 24 (mm). Each of the above-mentioned phosphor layers 12 is connected to each anode terminal 20 _P via an anode wiring 36 described later for each row unit, and each rib / grid electrode 22 is provided for each predetermined row. Each of them is connected to a common rib / grid terminal 20 _RG via a rib / grid wiring 48 described later.

Returning to FIG. 2, a plurality of mesh grid electrodes 24 are provided on the display surface 21 of the substrate 14 so as to cover a predetermined number (for example, 8) of rib grid electrodes 22, each of which is set in advance. Has been. As shown in FIG. 4 which shows a cross section of a main part of the display tube 10 along the longitudinal direction of the rib grid electrode 22, the substrate 14 of the mesh grid electrode 24 is shown.
A pair of leg portions 26, 26 protruding toward the display surface 21 are provided on both end sides in the width direction of the. This leg 26
Is for producing the mesh grid electrode 24,
The mesh portion is formed by etching or the like and then bent and formed by pressing or the like. On the other hand, on the display surface 21, a pair of mesh grid pads 28 are provided for each mesh grid electrode 24 at positions outside the rib grid electrodes 22 at both widthwise ends of the substrate 14.
28 are provided. Mesh grid electrode 24
Means that the pair of legs 26, 26 has pads 28, 28
Are embedded in the rib grid electrode 22 and fixed at an intermediate position in the thickness direction. The protrusion height from the flat portion located between the pair of leg portions 26, 26 is, for example, about hm = 700 (μm), and that of the mesh grid electrode 24 that actually functions as a control electrode. The flat portion is located at a height of about hm = 700 (μm) from the display surface 21. The length of the flat portion, that is, the installation distance between the leg portions 26, 26 is about Lm = 26 (mm), which is longer than the display pattern length Ld. In addition, each mesh / grid electrode 24 has a mesh / grid wiring 30 described later.
_Are connected to the mesh / grid terminals 20 _MG , respectively.

The electrode structure on the substrate 14 will be described in detail below with reference to FIG. On the display surface 21 of the substrate 14, the thick film conductor paste is applied by the screen printing method.
The anode wiring 36 is formed so as to be connected to the anode terminal 20 _P by being printed and baked to a thickness of about (μm), or by vapor deposition and etching treatment of an aluminum thin film or the like. An insulating layer 40 is formed on the anode wiring 36 so as to cover substantially the entire surface of the display surface 21 and has an appropriate through hole 38 penetrating in the thickness direction. This insulator layer 40 is
For example, a thick film insulating paste composed of a low melting point glass and a coloring pigment is applied by a screen printing method in a thickness of about 30 to 40 (μm) and baked.

A phosphor layer 12 is formed on the insulator layer 40.
A plurality of dot-shaped anodes 42 similar to the above are formed at positions where they are electrically connected to the anode wiring 36 through the through holes 38. The anode 42 is a thick film printing paste containing graphite as a main component in a predetermined dot pattern of 40 (μm).
It is printed and fired with a certain thickness. The phosphor layer 12 is formed, for example, by printing a thick film phosphor paste on the anode 42.

Around the phosphor layer 12 and the anode 42, a thick film insulating paste is printed to form a rib-shaped wall 44 on the insulator layer 40 which is in contact with and surrounded by the outer peripheral edges thereof. It is erected. This ribbed wall 44
Is a laminated film formed by repeatedly printing a thick film insulating paste made of an insulating material such as low-melting glass or an inorganic filler in a predetermined pattern with a line width of about w = 120 to 150 (μm). From the surface of the insulator layer 40
200 (μm), 100 to 120 (μm from the surface of the phosphor layer 12
It has a height of about m). The rib / grid electrode 2
2 is that a thick film conductor paste containing a particulate conductive material such as silver, palladium, aluminum, nickel, and carbon is printed on the top of the rib-shaped wall 44 with a thickness of about 10 to 50 (μm). It is fixedly formed. Therefore, the rib grid electrode 22 has an upper surface with hr =
It is provided so as to have a height of about 210 to 250 (μm), and the printing pattern of the rib-shaped wall 44 is the same as the pattern shape of the rib grid electrode 22 shown in FIG.

On the rib / grid electrode 22, for example, a thick film insulating paste similar to the rib-shaped wall 44 is formed by printing in a predetermined pattern so as to have electrical insulation, and hs = 15 to Height (thickness) of about 30 (μm)
A plurality of dot-shaped convex portions 46 having
That is, the convex portion 46 is provided on the upper surface of the rib grid electrode 22 so as to project from the upper surface toward the mesh grid electrode 24 side. As shown in FIG. 3, the convex portion 46 has a substantially circular planar shape with a diameter of about 120 to 150 (μm) which is substantially the same as the width of the rib / grid electrode 22. Grid electrode 22
It is distributed almost uniformly on the top and covers a part of its upper surface.
Each of the convex portions 46 is a region (in FIG. 3, the phosphor layer 12 in FIG. 3) sandwiched between mutually adjacent (more correctly, vertically and horizontally adjacent) of the phosphor layers 12 arranged in a matrix.
a position outside the area indicated by diagonal lines around a),
That is, in the region corresponding to the outside of the corners of the rectangular phosphor layer 12, between the diagonally adjacent ones of the phosphor layers 12 arranged vertically and horizontally, specifically, between the corners. To do. In other words, the convex portions 46 are provided on the intersections of the portions extending along the row direction and the portions extending along the column direction, which are the constituent portions of the rib / grid electrode 22 that are orthogonal to each other. Therefore, the rib / grid electrode 22 has its upper surface partially covered with the convex portions 46, that is, the insulator. As described above, since the height of the rib / grid electrode 22 is about hr = 210 to 250 (μm), the protrusion 46
The height of the upper surface of is about 225 to 280 (μm).

Therefore, as described above, since the mesh grid electrode 24 is provided at a height position of about hm = 700 (μm) from the display surface 21, as shown in FIG. The distance between the electrode 24 and the rib / grid electrode 22 and the convex portion 46 is gm = 450, respectively.
.About.490 (.mu.m) and gs = 420.about.475 (.mu.m), which is installed at a height position separated from both. That is, the mesh grid electrode 24 is not in contact with not only the rib grid electrode 22 but also the protrusions 46 provided thereon.

On the display surface 21 of the substrate 14, a plurality of rib grids are formed near both ends in the longitudinal direction of the rib grid electrode 22 on the same plane as the anode wiring 36 by using the same material and method. The pad 48 is provided, and the rib / grid pad 48 and the rib
Rib grid wiring 5 for connecting to the grid terminal 20 _RG
0 is provided, and each of the rib / grid electrodes 22 is provided with a through paste provided in the vicinity of one end of the rib / grid electrode 22 by a conductor paste layer 52 applied and formed on either one of both ends thereof by a screen printing method or the like. By being connected to the rib / grid pad 48 through the hole 38, it is connected to the rib / grid terminal 20 _RG through the rib / grid wiring 50. Rib grid wiring 5
0 is provided at a position outside the anode 42 in the width direction of the substrate 14 in order to avoid interference with the anode 42 and the anode wiring 36. The top portion (upper surface) of the convex portion 46 is located above the conductor paste layer 52. The rib / grid pad 48 is
A plurality of ribs / grid electrodes 22 are provided at one and the other ends of the grid electrode 22 at a center interval that is approximately twice the center interval of the grid electrode 22 and are arranged in the column direction. The rib grid pads 48 are alternately connected along the longitudinal direction of the substrate 14 (see FIG. 3).

Further, the mesh / grid pad 28 is formed by printing using a thick film conductor paste similar to that of the rib / grid electrode 22 to a thickness of, for example, about 30 (μm). The insulating layer 40 is also provided with a through hole 38 penetrating therethrough at a position corresponding to the mesh grid pad 28. The mesh grid pad 28 has its through holes 38.
Is connected to the mesh / grid wiring 30 provided on the substrate 14 in the same manner as the anode wiring 36 and the like.
Therefore, the mesh grid electrode 24 has legs 26
And electrically connected to the mesh grid wiring 30 through the mesh grid pad 28. As described above, since the mesh / grid electrode 24 is provided for every eight units of the rib / grid electrode 22, the center interval of the mesh / grid pad 28 is the center of the rib / grid pad 48. It is about several times the interval.
The mesh / grid pads 28 are located outside the rib / grid pads 48 on both ends of the rib / grid electrode 22 in the longitudinal direction of the substrate 14, that is, the anode 42 in the width direction of the substrate 14. It is provided at the outer position side by side along the longitudinal direction of the substrate 14.

The mesh grid electrode 24 is fixed to the display surface 21 as follows, for example. That is, after the thick film conductor paste for forming the mesh / grid pad 28 is applied on the insulator layer 40 and before the drying, that is, while the paste has sufficient viscosity,
The press-molded mesh / grid electrode 24 is conveyed onto the substrate 14 while being attracted to the molding die by a magnet or the like, and the leg 26
Is pushed to a predetermined depth of the paste, the adsorption is released, and the paste is released from the mold. As a result, the leg 26 is held in the pushed-in depth position due to the interaction between the viscosity of the paste and the large specific gravity, and the mesh / grid electrode 24 is fixed on the insulator layer 40 by heat treatment of the leg 26. To be done. At this time, the height of the leg portion 26 is hm = 700 (μ
(m) is sufficiently small that the mesh
The grid electrode 24 can be easily removed from the mold,
High workability is secured.

Returning to FIG. 2, a pair of filament supporting frames 32 (only shown on the right side) having the cathode terminals 20 _K are fixedly provided at both ends of the substrate 14, respectively. Support frame 3
Between the two, a plurality of thin wire (filament) -shaped cathodes 34 functioning as direct heating cathodes are installed at a predetermined height position parallel to the longitudinal direction of the substrate 14 and separated from the display surface 21. ing. Since the cathode 34 is located above the mesh grid electrode 24, the protrusions 46 are
Can be said to be provided so as to project toward the cathode 34. It should be noted that the fluorescent display tube 10 is provided with an exhaust hole for evacuating and sealing the inside of the vacuum container, a getter for maintaining the internal vacuum degree after sealing, and the like.
These are omitted in.

FIG. 5 is a diagram for explaining an example of the connection state of the wirings connected to the rib grid electrode 22, the mesh grid electrode 24, and the anode 42, respectively. Mesh grid electrode 2 as indicated by the dashed line in the figure
4 are provided in common for each of the eight rib grid electrodes 22 (that is, so as to cover them), and the mesh grid wirings 30a and 30 are provided, respectively.
b, ˜30k (only 30a and 30b are shown. Further, k is the number of mesh grid electrodes 24, and in the example of the figure, the number of anodes 42 provided in each row, that is, the number of columns of the phosphor layer 12 is m. Different meshes via m / 8)
It is connected to the grid terminal 20 _MG . The rib / grid electrodes 22 corresponding to the same position for each unit in which the mesh / grid electrodes 24 are provided in common are connected to the common rib / grid wiring 50. That is, the plurality of rib grid electrodes 22 are formed on the substrate 14 by, for example, 8
Rib grid wiring 50a, 50b, to 5
Each of 0h is sequentially connected in the column direction. Further, the anode 42 includes a plurality of anode wirings 36a, 36b, to 36n, each of which is provided for each row (where n is the number of the anodes 42 provided for each column. In this embodiment, 1). ≤n
≦ 32) are commonly connected.

When driving the fluorescent display tube 10 having the above-described structure, the mesh / grid wirings 30a, 30b, 30k, 30k, 30k, 30k, 30k, 30k, 30k, 30k, 30k, 30k, 30k, 30k, 30k, 30k, 30k, 30g, 30k are provided with a predetermined heating current constantly flowing through the cathodes 34. For example, a positive voltage (accelerating voltage) of, for example, about 20 (V) is sequentially applied to the mesh grid electrode 24 to the zero (V) cathode 34 to scan the mesh grid electrode 24, and each mesh grid electrode 24 is scanned. Electrode 2
During the period when the acceleration voltage is applied to the rib 4,
Ribs through the grid wirings 50a, 50b, to 50h
An acceleration voltage similar to that of the mesh grid electrode 24 is sequentially applied to the grid electrode 22 for scanning, and further, a positive voltage is applied to a predetermined phosphor layer 12 in synchronization with the timing of the scanning. As a result, the thermoelectrons emitted from the cathode 34 are
Of the phosphor layer 12 that is accelerated by the mesh grid electrode 24 and the rib grid electrode 22 to which a positive voltage is applied, is positioned below the mesh grid electrode 24, and is surrounded by the rib grid electrode 22. , Collides with the one to which a positive voltage is applied via the anode wirings 36a, 36b, to 36n, and causes it to emit light.

On the other hand, even if a positive voltage is applied to the phosphor layer 12, the cathode 34 is formed on either the mesh grid electrode 24 on the upper side thereof or the rib grid electrode 22 surrounding it.
If a negative bias voltage (cut-off bias) of about several (V) is applied to the phosphor layer 1,
2, the phosphor layer 12 does not emit light. That is, the column of the phosphor layer 12 to emit light is selected by the combination of the mesh grid electrode 24 and the rib grid electrode 22, and the row 42 is selected in synchronization with the column selection timing. 36), only the predetermined phosphor layer 12 is selectively made to emit light. Therefore, in the state where the thermoelectrons are emitted by the current flowing through the cathode 34, the mesh grid electrode 2
4 and the rib grid electrode 22 are sequentially applied with an accelerating voltage, a positive voltage is applied to a desired one of the phosphor layers 12 in a so-called grid multi-matrix system. The light emission display is performed in a desired pattern by the dynamic driving.

During the above driving, the grid electrode 2
When the thermoelectrons directed to the phosphor layer 12 are incident on the phosphor layers 2 and 24, a grid current flows, and heat is generated according to the amount of the current and the kinetic energy of the incident thermoelectrons. At this time, the mesh grid electrode 24 is provided with a pair of leg portions 26, 2 provided at both ends of the display surface 21 in the width direction.
It is erected on the display surface 21 by being supported by 6,
There is no support at all on the rib grid electrode 22 between them. Therefore, when the legs 2 fixed to the display surface 21 are thermally expanded by heat generation.
Since 6 and 26 cannot move, the flat portions that are located between them and are not directly supported move upward or downward as shown in FIG. 1 depending on the amount of thermal expansion. It can be deformed to be convex. Further, even when a shock or vibration is applied during use, the flat portion is vibrated with the both end portions being supported as nodes and is similarly deformed.
However, as described above, since the electrically insulating convex portions 46 are provided on the rib grid electrode 22 in a substantially uniform distribution, for example, the mesh grid electrode 24 is convex downward. These deformations cannot cause these contacts. Therefore, the distance gm between the rib grid electrode 22 and the mesh grid electrode 24 is 450 to 490 (μ
Despite the small size of m), the electrical short circuit between them is prevented, so that the reliability of the display tube 10 is enhanced. That is, the convex portion 46 functions as an insulating spacer for preventing a short circuit between the grid electrodes 22 and 24.

In short, according to this embodiment, the electrically insulating convex portions 46 are provided on the rib / grid electrode 22 in a substantially uniform manner. Therefore, even if the mesh / grid electrode 24 is distorted during use of the fluorescent display tube 10 as described above, the rib / grid electrode 22 is provided with the electrically insulating projections 46 provided on the upper side of the rib / grid electrode 22. The contact between the electrode 22 and the mesh grid electrode 24 is prevented, and the distance between them is maintained at a size equal to or higher than the height of the convex portion 46. Therefore, the rib grid electrode 2
Since the erection distance of the mesh / grid electrode 24 can be lengthened to about Lm = 26 (mm) as described above while ensuring the electrical insulation between the mesh grid electrode 24 and the mesh grid electrode 24, it is determined by the erection distance Lm. The display pattern length in the erection direction (that is, the width direction of the fluorescent display tube 10) is about Ld = 24 (mm) or more, and the grid multi-matrix using the rib grid electrode 22 and the mesh grid electrode 24 in the past is used together. 16 was considered the limit of the method
It can be dramatically lengthened compared to (mm). This allows
It is possible to obtain the fluorescent display tube 10 that can be used for a variety of graphic displays than ever before.

Further, in this embodiment, the convex portion 46 is
Outer positions of the corners deviating from the region sandwiched between vertically and horizontally adjacent ones of the phosphor layers 12, that is, along the row direction which is a mutually orthogonal component part of the rib / grid electrode 22. Is provided at the intersection of the extending portion and the extending portion along the column direction. Therefore, the contribution to the control of the electrons flying from the cathode 34 toward the phosphor layers 12 is related to the portion of the rib / grid electrode 22 that extends along the edges of the phosphor layers 12, that is, the phosphor layers 12 that are vertically and horizontally adjacent to each other. Since it becomes large in the region sandwiched between the two, it is possible to prevent the control function of the rib / grid electrode 22 from being deteriorated due to the provision of the electrically insulating convex portion 46. In addition, even if the control function is hindered by providing the convex portion 46 on the portion of the rib / grid electrode 22 that corresponds to the outside of the corner of the phosphor layer 12, the function continues on both sides thereof. That is, the portion extending along the edge of the phosphor layer 12 is sufficiently supplemented.

Next, another embodiment of the present invention will be described. In the following embodiments, the same parts as those in the above-mentioned embodiments are designated by the same reference numerals and the description thereof will be omitted.

FIG. 6 is a view corresponding to FIG. 3 showing the arrangement of the convex portions 46 according to another embodiment of the present invention. In the figure, the protrusions 46 are located at a plurality of locations in the vicinity of the central portion of the rib / grid electrode 22 in the longitudinal direction, that is, centered at a position 1/2 (= Ld / 2) of the display pattern length Ld from the end portion. It is provided only in the vicinity and on both sides in the longitudinal direction, and is not provided on both end sides. The individual shapes and forming methods of the convex portions 46 are the same as those in the above-described embodiment. That is, also in the present embodiment, the convex portion 46 is located outside the corner portion of the phosphor layer 12 that is outside the region sandwiched between vertically and horizontally adjacent ones, and is in the row direction of the rib grid electrode 22. Since it is provided on the intersection of the portions that respectively extend in the column direction and the column direction, it is suppressed that the control function of the rib / grid electrode 22 is deteriorated due to the provision of the electrically insulating convex portion 46. To be done.

Even in the above-described manner, the contact between the mesh grid electrode 24 and the rib grid electrode 22 can be prevented by the convex portion 46 as in the above-described embodiment.
That is, when the mesh / grid electrode 24 is deformed due to vibration or thermal expansion, as shown in FIG. 1, the strain ε is larger at the central position in the erection direction, forming an arc shape. Therefore, if the protrusions 46 prevent the mesh / grid electrode 24 and the rib / grid electrode 22 from contacting each other in the vicinity of the central portion where the strain ε is largest, mutual contact can be prevented over their entire length. .

In short, in this embodiment, the convex portion 46
Is provided at a position corresponding to the vicinity of the central portion in the erection direction of the mesh grid electrode 24, that is, the direction of the display pattern length Ld. Therefore, the mesh grid electrode 24
Is a leg portion 26 provided at both ends of the mesh grid electrode 24 in order to support a portion near the central portion in the erection direction, that is, a portion of the mesh grid electrode 24 located on the rib grid electrode 22.
In the vicinity of the central portion between the two, it is supported by the electrically insulating convex portion 46. Therefore, the ribs on the entire surface of the mesh grid electrode 24 are prevented because the protrusions 46 prevent the mesh grid electrode 24 from being in contact with the rib grid electrode 22 at the central portion in the erection direction where the strain is greatest. A short circuit with the electrode 22 is sufficiently suppressed.

FIG. 7 is a view corresponding to FIG. 4 for explaining still another embodiment of the present invention. In the figure, on the both end sides of the rib grid electrode 22 (that is, both end sides of the rib-shaped wall 44 or the outer peripheral side), the respective outer positions of the rib grid pads 48 arranged in the longitudinal direction of the substrate 14,
That is, at a position outside the anode 42 in the width direction of the substrate 14, substantially the same as the rib-shaped wall 44 or more [that is, 200 (μ
m) or more] and a plane shape made of a similar insulator having a substantially rectangular shape (that is, the pad for mesh grid 28
Substrate portions 54, 54 having a substantially similar planar shape) are provided side by side along the longitudinal direction of the substrate 14 (row direction perpendicular to the paper surface). On the pedestal portion 54, a conductor layer 56 formed by applying a conductor paste similar to that used for forming the rib grid electrode 22 is provided. The height of the conductor layer 56 is, for example, 10 to 50.
The top of the rib grid electrode 22 is positioned above the top of the rib grid electrode 22 by about (μm). The mesh / grid electrode 24 is provided with fixing portions 58 and 58 located on the same plane as the mesh portion at both end positions where the leg portions 26 and 26 were provided in FIG. 4 and the like. 5
8 and 58 are fixed in a state of being embedded in the conductor layers 56 and 56, respectively, so that the conductor layers 56 and 56 are disposed on the display surface 21. That is, in the present embodiment, the mesh-shaped grid electrode 2 is a metal thin plate having a flat mesh shape as a whole.
Used as 4.

Further, at a position further on the end side of the pedestal portion 54 in the width direction of the substrate 14, the mesh / grid wiring 30 is provided on the substrate 14 and the insulating layer 4 is provided.
A through hole 38 exposing the wiring 30 is provided at 0. Then, a conductor paste layer 52 similar to that of the rib grid electrode 22 is applied and formed on the through hole 38, and the conductor paste layer 5 is formed.
2, the mesh / grid wiring 30 and the conductor layer 56 are electrically connected. Therefore, the mesh / grid electrode 24 is fixed to the conductor layer 56 and is connected to the wiring 30 at the same time. On the other hand, the rib / grid electrode 22
Similar to the case of FIG. 4, the dot-shaped convex portions 46 are provided on the upper side, but the conductor layer 56 is in contact with (or substantially in contact with) the convex portions 46 of the mesh grid electrode 24.
Is fixed by. That is, the mesh / grid electrode 24 has the convex portions 46 in a state where no distortion occurs.
To (or substantially contact with) the rib / grid electrode 22 side even if distortion occurs during driving or the like. In this embodiment, the height hs of the convex portion 46 (see FIG. 4) is 200 (μ
m) or more, mesh grid electrode 24
When not deformed, the mutual distance from the rib / grid electrode 22 is about gm = hs = 200 (μm) or more. That is,
The mutual spacing gm is determined by the control function of the rib grid electrode 22 when an accelerating voltage is applied to the mesh grid electrode 24 and an erasing voltage (negative bias voltage) is applied to the rib grid electrode 22. The size is set so that the light emission of the enclosed phosphor layer 12 is sufficiently blocked. Also, the pad for mesh grid 28
Is composed of the base portion 54 and the conductor layer 56 described above, and the plane size of the base portion 54 is substantially the same as the size of the pad 28 shown in FIG.

In short, in this embodiment, the rib-shaped wall 44 is provided with the pedestal portions 54 having substantially the same height or higher on both end sides, and the mesh / grid electrode 24 has the pedestal portions 54.
It is supported by being fixed by the conductor layer 56 on top.
Therefore, since the pedestal portion 54 is provided at about the arrangement height of the mesh / grid electrode 24, the flat-plate-shaped mesh / grid electrode 24 can be used as described above, so that the leg portion 26 is unnecessary. However, there is an advantage that a press molding process for bending and forming it is unnecessary. Further, it is possible to change the height of the mesh / grid electrode 24 by changing the height of the base portion 54, and at the same time as fixing the mesh / grid electrode 24 to the base portion 54, It is possible to electrically connect to the mesh grid wiring 30 provided on the substrate 14 via.

Further, in this embodiment, the mesh grid electrode 24 is arranged in contact with (or substantially in contact with) the convex portion 46. Therefore, the mesh grid electrode 24 is substantially placed on the rib grid electrode 22 in a state of contacting (or substantially contacting) the convex portion 46, and thus the mesh grid electrode 24 is provided on the substrate 14. At the time of the disposition, the height position and the parallelism with the display surface 21 of the substrate 14 can be controlled with high accuracy, and the height position changes when the mesh / grid electrode 24 is distorted. Since the distortion is further suppressed, the distance from the cathode 42 is changed due to the distortion, which further suppresses the brightness change.

FIG. 8 is a diagram corresponding to the main part of FIG. 4 for explaining still another embodiment. In this embodiment, ribs
The convex portion 4 provided in a dot shape on the grid electrode 22
The rib / grid electrode 2 is provided at an intermediate position in the height direction of 6
The mesh / grid electrode 24 is mounted on the substrate 14 by being embedded in a state in which the electric insulation with respect to 2 is secured. Although the drawing shows only the intermediate portion of the erected mesh / grid electrode 24, the mesh / grid electrode 24 has leg portions 26 provided at both ends thereof as shown in FIG. 4 and the like. Alternatively, the whole may be flattened as shown in FIG. Further, the mesh grid electrode 24 having the leg portions 26 may be fixedly mounted on the base portion 54 as shown in FIG. 7.
In addition, the convex portion 46 has the above-described grid electrodes 22, 2
In order to secure the minimum mutual distance of 4 gm = 200 (μm), a sufficient height, for example 25, is taken into consideration in consideration of the thickness necessary for embedding and fixing the mesh grid electrode 24.
It is formed at a height of about 0 to 300 (μm).

According to this embodiment, the mesh / grid electrode 24 is fixedly provided on the rib / grid electrode 22 in a state of being embedded in the middle position in the height direction of the convex portion 46. Therefore, the mesh grid electrode 24 is attached to the substrate 1
In the case where the mesh grid electrode 24 can be distorted due to vibration or heat generation, the height position and parallelism with the display surface 21 of the substrate 14 can be controlled with high accuracy when arranged on the substrate 4. However, the change of the height position is substantially prohibited. In other words, the mesh grid electrode 24 is moved in both directions of approaching the rib grid electrode 22 (that is, separating from the cathode 32) and conversely approaching the cathode 32 (that is, separating from the rib grid electrode 22). Distortion and vibration are suppressed. Therefore, it is further suppressed that the distance from the cathode 42 changes due to the distortion or the vibration, and thus the change in brightness and the shortening of the life are caused. In the figure, the convex portions 46 are provided substantially uniformly distributed over the entire length of the rib / grid electrode 22 in the longitudinal direction, but as shown in FIG. 6, in the vicinity of the central portion in the longitudinal direction. The same effect can be obtained even when it is provided only in the.

FIG. 9 is a view for explaining another shape of the convex portion provided on the rib / grid electrode 22. In the embodiment of FIGS. 2 to 8, the convex portion 46 having a circular planar shape is used.
However, instead of this, a rectangular parallelepiped convex portion 60 having a rectangular planar shape and a rectangular sectional shape in the height direction of the rib-shaped wall 44 may be used as shown in the figure.
The convex portion 60 has a substantially square shape with a side length of about 120 to 150 (μm) and a height of about 15 to 30 (μm). That is, it is provided in the same size as the convex portion 46 except that the shape is slightly different. Further, the arrangement position on the rib / grid electrode 22 is similar to that of the convex portion 46, and may be distributed over substantially the entire surface, or may be provided only near the central position in the erection direction. Even when such a convex portion 60 is provided on the rib grid electrode 22, as in the case where the convex portion 46 is provided, the convex grid 60 and the mesh grid electrode 24 are almost not impaired. Contact can be suppressed.

Although the convex portion 60 shown in FIG. 9 has a substantially square shape, the length of the rib grid electrode 22 in the longitudinal direction is orthogonal to that as shown by the broken line in the figure. Even if it is a rectangular shape which is slightly longer than the above, there is no particular hindrance to the function of the rib / grid electrode 22, and the same effect can be obtained.

FIG. 10 is a diagram showing a planar shape of a rib / grid electrode 62 having another shape to which the present invention is applied. In the figure, each of the plurality of rib grid electrodes 62 is
A trunk portion 62a extending in the row direction (vertical direction in the drawing) passing between the plurality of phosphor layers 12 forming each column, and the trunk portion 6 thereof.
2a and branch portions 62b extending in the row direction (left-right direction in the figure) at substantially equal intervals to form a "fish bone shape". That is, in this embodiment, the rib grid electrodes 62 are provided so as to pass between the columns of the phosphor layers 12. Between the tips of the branch portions 62b, 62b provided on the rib / grid electrodes 62, 62 adjacent to each other, a sufficient gap s is provided to ensure electrical insulation between the ribs 62b, 62b. -Each of the grid electrodes 62 is electrically independent from each other. Therefore, the phosphor layer 12
Each of the ribs is applied with a predetermined acceleration voltage to the two rib grid electrodes 62, 62 located on both sides (left and right sides in the figure) in the column direction, so that the acceleration voltage is applied to substantially the entire circumference. It is surrounded by the rib / grid electrode 62. As described above, a plurality of (two in this embodiment)
The present invention is similarly applied to the case where substantially the entire circumference of each of the phosphor layers 12 in a row is surrounded by the rib / grid electrode 62 (of the present invention). That is, “a plurality of ribs / grid electrodes provided for each row of phosphor layers” can be used for one row of phosphor layers 12 as long as the rows of the phosphor layers 12 can be selected substantially. And a plurality of rib grid electrodes 62 that are commonly used with the column of the phosphor layer 12 adjacent thereto are also included.

Further, the trunk portion 62 of the rib / grid electrode 62
Among the intersections of a and the branch portion 62b, at a position of approximately half (Ld / 2) of the display pattern length Ld, that is, in the vicinity of the central portion in the longitudinal direction of the trunk portion 62a, the embodiment shown in FIG. Similarly, the convex portions 46 are provided on the rib grid electrode 62. The above intersection point positions correspond to the positions corresponding to the corners of the phosphor layer 12 of the grid electrode 22 in each of the above-described embodiments. That is, also in this embodiment,
The convex portion 46 is provided at a position outside the region between the phosphor layers 12 adjacent to each other in the vertical and horizontal directions. Therefore, also in this embodiment, similarly to the embodiment shown in FIG. 6, the convex portion 46 for preventing the contact between the rib grid electrode 62 and the mesh grid electrode 24 located thereabove is formed. It is provided on the rib / grid electrode 62 to enhance the reliability of the display tube 10. The shape of the convex portion 46, the dimensions of each portion, and the like are the same as those in the above-described respective embodiments, and not only the central portion but also the rib / grid electrode 62.
It may be provided at all the intersections of the trunk portion 62a and the branch portion 62b among the above, and the shape thereof may be as shown in FIG.

FIG. 11 shows still another rib / grid electrode 6
It is a figure which shows the planar shape of FIG. In the figure, a plurality of phosphor layers 66, each of which has a slightly elongated hexagonal shape, are arranged in a zigzag pattern, and each of the plurality of rib grid electrodes 64 is arranged between the plurality of phosphor layers 66. Is bent in the column direction (either the right direction or the left direction alternately) and passes through in the vertical direction in the figure. Therefore, each of the phosphor layers 66 is surrounded by the two rib grid electrodes 64 adjacent to each other at a part of the entire circumference and the rest. Also in this embodiment, in the vicinity of the central portion of the display pattern length Ld in the length direction, the convex portion 46 is provided on the bent portion of the rib / grid electrode 64 that is bent along the edge of the phosphor layer 66. ing. As you can see from the figure,
It exists at a corner portion of the phosphor layer 66 that is out of the region sandwiched between the phosphor layers 66 adjacent to each other. Therefore, also in this embodiment, since the convex portion 46 is provided at a position outside the region sandwiched between the phosphor layers 66 adjacent to each other, the function of the rib / grid electrode 64 is hardly impaired. , The contact with the mesh / grid electrode 24 located thereabove can be blocked by the projection 46.

That is, not only when the rectangular phosphor layers 12 as shown in FIGS. 2 to 10 are provided on the display surface 21 side by side in the vertical and horizontal directions, but also the phosphors having a shape other than the rectangular shape such as the hexagonal shape. The present invention can be suitably applied even when the layers 66 are provided in a staggered pattern. Therefore, in the "matrix" referred to in the present application, not only the phosphor layers 12 are vertically and horizontally aligned, but also the zigzag phosphor layers 66 are distributed substantially uniformly on the display surface 21. Various arrangement patterns are included as long as they are suitable for graphic display.

FIG. 12 is a diagram for explaining still another embodiment shown in FIG.
It is a figure corresponding to. In the figure, an insulating spacer layer 68 covering the entire upper surface of the rib / grid electrode 22 is provided.
Is provided. The insulating spacer 68 has a convex portion 46.
It is formed by screen-printing a thick film insulating paste similar to (i.e., similar to the rib-shaped wall 44) on the rib grid electrode 22, and has the same height dimension as that of the convex portion 46. There is. Therefore, also in this embodiment, the insulating spacer layer 68 preferably suppresses a short circuit between the grid electrodes 22 and 24 when the mesh grid electrode 24 is distorted. In this way, the convex portion 46
Even when the insulating spacer layer 68 having the same function as the above is provided so as to cover the upper surface of the rib / grid electrode 22, for example, a material having a sufficiently thin thickness or a sufficiently low dielectric constant is used. By this, rib grid electrode 2
It is possible to prevent contact with the mesh grid electrode 24 while maintaining the function of 2. That is, the rib grid electrode 22
As long as it is possible to sufficiently suppress the occurrence of a large change in the electric field formed by, the “electrically insulating convex portion” in the claims is defined as an arbitrary position on the rib / grid electrode 22 at a part or the whole. Can be appropriately provided. In the drawing, the upper surface of the insulating spacer layer 68 and the bottom surface on the rib / grid electrode 22 side have the same shape, and the rib-shaped wall 44 has a rectangular cross-sectional shape in the height direction. Four
Similarly to the embodiments shown in FIG. 1 and the like, the cross-sectional shape may be a semicircle or semi-elliptical shape, etc., in which the width dimension in the cross section gradually decreases from the bottom surface to the top.

Although one embodiment of the present invention has been described in detail with reference to the drawings, the present invention can be carried out in still another mode.

For example, in the embodiment, the mesh grid wiring 30 and the rib grid wiring 50 are all provided on the substrate 14 in a state of being covered with the insulating layer 40, but some or all of them are provided. The insulating layer 40 may be provided so as to connect the mesh grid pad 28 or the rib grid pad 48 to the mesh grid terminal 20 _MG or the rib grid terminal 20 _RG .

Also, in the embodiment, the convex portions 46, 6
0, the insulating spacer layer 68 had electrical insulation by being formed by coating from a thick film insulating paste similar to that forming the rib-shaped wall 44, but the protrusions 46 and 60, and the insulating spacer layer 68. May be made of a material having a slight conductivity such that the mesh grid electrode 24 and the rib grid electrodes 22, 62, 64 are not substantially short-circuited.

Further, in the embodiment, the convex portions 46, 6
0, the insulating spacer layer 68 is the rib grid electrode 22, 6
The case where they are evenly distributed on 2, 64, etc., or they are provided only in the vicinity of the central portion in the longitudinal direction has been described.
4 are appropriately changed within a range in which contact between the ribs 4 and the rib / grid electrode 22 or the like is sufficiently suppressed. For example, ribs arranged at one or several positions between the phosphor layers 12 or arranged in the column direction.
It is also possible to provide every one to several grid electrodes 22 or the like.

Further, in the embodiment shown in FIGS. 2 to 5, eight rib grid electrodes 22 are assigned to each mesh grid electrode 24, that is, the phosphor layers 12 in eight rows are assigned. The number is appropriately changed according to the driving method, the use of the fluorescent display tube 10, and the like. Further, the size of each part such as the number of the phosphor layers 12 included in each row, the dot pitch, the display pattern length Ld, the erection length Lm of the mesh grid electrode 24, and the like depends on the use of the fluorescent display tube 10. It is changed accordingly.

Further, in the embodiment shown in FIG.
Although the planar mesh grid electrode 24 is fixed on the base 54 and the lower surface is brought into contact with the convex portion 46, even when it is fixed on the base 54, as shown in FIG. The mesh grid electrode 24 and the convex portion 46 may be arranged so as to be separated from each other. Further, the mesh grid electrode 24 having the leg portions 26 as shown in FIG. 4 and the like may be provided so as to be in contact with the convex portion 46 as shown in FIG. 7.

Although not illustrated one by one, the present invention can be variously modified without departing from the spirit thereof.

[Brief description of drawings]

FIG. 1 is a diagram illustrating a main part of a cross-sectional structure of a conventional grid-multi-matrix fluorescent display tube.

FIG. 2 is a partially cutaway perspective view showing a structure of a fluorescent display tube according to an embodiment of the present invention.

FIG. 3 is an enlarged view showing a main part of a display surface of the fluorescent display tube of FIG.

4 is a diagram illustrating a cross-sectional structure of the fluorescent display tube of FIG.

5 is a diagram illustrating an example of a wiring connection state of the fluorescent display tube of FIG.

FIG. 6 is a diagram corresponding to FIG. 3 for explaining another embodiment of the present invention.

FIG. 7 is a view for explaining another embodiment of the present invention and corresponds to FIG.

FIG. 8 is a diagram corresponding to a main part of FIG. 4 for explaining another embodiment of the present invention.

FIG. 9 is a perspective view illustrating a convex portion according to another embodiment of the present invention.

FIG. 10 is a diagram illustrating another example of a rib grid shape to which the present invention can be applied.

FIG. 11 is a diagram illustrating still another example of the rib / grid shape to which the present invention can be applied.

FIG. 12 is a convex portion (insulating spacer) according to another embodiment of the present invention.
It is a figure explaining.

[Explanation of symbols]

10: Fluorescent display tube 12: Phosphor layer 14: substrate 22: Rib grid electrode 24: Mesh grid electrode 34: cathode 42: Anode 44: ribbed wall {46, 60: convex portion, 68: insulating spacer} (convex portion)

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shuji Baba 2160 Yatsunami, Yanami, Sansu, Yasu-cho, Asakura-gun, Fukuoka Prefecture Kyushu Noritake Co., Ltd. (56) Reference JP-A-8-36975 (JP, A) JP 61-250943 (JP, A) Actual development flat 2-140749 (JP, U) Actual development flat 1-143059 (JP, U) Actual development Sho 64-255 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) H01J 31/15

Claims (5)

(57) [Claims] 1. A phosphor layer fixed on a plurality of anodes arranged in a matrix on a substrate, and a cathode erected above the phosphor layer in a vacuum space. A plurality of mesh grid electrodes laid between the phosphor layer and the cathode in predetermined rows of the phosphor layer in order to control electrons and selectively cause the phosphor layer to emit light. And a plurality of ribs provided for each row of the phosphor layer on top of rib-shaped walls protruding above the phosphor layer at positions surrounding the phosphor layer below the mesh grid electrode, respectively. A fluorescent display tube including a grid electrode, the fluorescent display tube including an electrically insulating convex portion provided at a predetermined position on the rib / grid electrode. 2. The fluorescent display tube according to claim 1, wherein the convex portion is provided at a position outside a region sandwiched between adjacent ones of the phosphor layers. 3. The fluorescent display tube according to claim 1, wherein the mesh grid electrode is arranged so as to be substantially in contact with the convex portion. 4. The fluorescent display tube according to claim 1, wherein the mesh grid electrode is embedded at an intermediate position in the height direction of the convex portion. 5. The mesh / grid electrode is supported by being fixed by a conductive fixing material on a base portion having a predetermined height provided on the outer peripheral side of the rib-shaped wall. The fluorescent display tube according to any one of 1 to 4.