JP3290143B2 - Method for manufacturing anode substrate of 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 method for manufacturing an anode substrate of a rib-grid type fluorescent display (VFD).

[0002]

2. Description of the Related Art Phosphor layers are respectively fixed on a plurality of anodes provided on a display surface of a substrate, and electrons generated from a cathode provided above the display surface in a vacuum space are generated by the phosphor layers. As a kind of a fluorescent display tube of a type in which a predetermined phosphor layer selectively emits light by being controlled by a control electrode (grid electrode) provided between the layer and the cathode,
A so-called rib-grid type fluorescent display tube is known in which a rib-like wall protrudes higher than the phosphor layer at a position surrounding the phosphor layer, and the above-mentioned grid electrode is provided at the top thereof. For example, there is a fluorescent display tube described in Japanese Patent Application Laid-Open No. 8-287853 filed by the applicant of the present invention.

In such a fluorescent display tube, several tens of thermions emitted from a filament-shaped cathode are applied to a grid electrode.
By applying a relatively low-pressure positive acceleration voltage of the order of (V), the phosphor layer is accelerated and collided toward the phosphor layer located on the anode. The operating voltage is low and the display is clear because the surface of the phosphor layer where the light is collided is located on the display side. In addition, color display is possible by preparing phosphor layers with different emission colors. Because
It is widely used as a display component for audio equipment and dashboards of automobiles. In particular, according to the rib-grid type fluorescent display tube, since a mesh-like grid covering the phosphor layer is not used, thermal deformation of the grid when the light emitting pattern of the phosphor layer is enlarged as the size becomes large is reduced. There is an advantage that display defects such as uneven brightness and short-circuit caused by the display are eliminated, and that the brightness of the fluorescent display tube is reduced due to the aperture ratio of the mesh grid.

[0004]

FIG. 3 shows the above-mentioned ribs.
It is a figure explaining the principal part section of the substrate structure of an example of a grid type fluorescent display tube. In the figure, an insulator layer 38 covering substantially the entire surface of the substrate 12 is provided on a substrate 12, and a plurality of graphite layers (anodes) 40 each having a phosphor layer 20 fixed thereto are provided on the insulator layer 38. Be provided. Each of the plurality of phosphor layers 20 is surrounded by a rib-shaped wall 44 made of an insulator, and the grid electrode 22 is fixed to the top of the rib-shaped wall 44. The ribs 44 are formed on the anode 4 by using, for example, a thick film screen printing method.
After printing 0, a thick film insulating paste is repeatedly printed and laminated to form a predetermined height. However, on the substrate 12, as shown in the figure, two types of rib-shaped walls, a rib-shaped wall 44a protruding from the insulator layer 38 and a rib-shaped wall 44b protruding from the anode 40, are provided. 44
May be mixed, so that, due to the difference in the height of the protruding surfaces on which they are formed, the lower part of the rib-like wall 44b or the phosphor layer 2 partitioned by the rib-like wall 44a may be used.
There is a problem that 0, 20 contact or the like occurs.

That is, the two types of rib-like walls 44a, 4a
4b has the same structure except that the height of the protruding surface is different, so that it is printed and formed on the substrate 12 at the same time. At this time, as shown in FIG. The first layer 62a of the paste layer 62
The one for forming 4 a is provided on the insulator layer 38, and the one for forming the rib-shaped wall 44 b is provided on the anode 40. Therefore, as shown in the center of the figure, a gap corresponding to the thickness of the anode 40 is generated between the surface of the insulator layer 38 between the anodes 40 and 40 and the screen 60 indicated by a dashed line. If the amount of paste discharged (paste missing) from the screen 60 is increased for the purpose of printing the thick film insulating paste, the amount of paste discharged on the anode 40 that is brought into close contact with the screen 60 becomes excessive. Width (opening 6
(Width of 0a) dp. If the ribs of the rib-like wall 44b are generated due to the adjustment of the printing conditions to the rib wall 44a in this manner, the current at the peripheral portion of the phosphor layer 20 and the emission of light are hindered, and as shown in FIG. Since the position indicated by the diagonal lines becomes dark, there is a problem that the display quality is reduced.
In addition, since the phosphor layer 20 is provided in contact with the inner peripheral surface of the rib-shaped wall 44, as shown in FIG. Will be present in the insulator.

On the other hand, the height difference of the application surface of the thick film insulating paste based on the difference of the formation position (projection surface) height, that is, the step difference between those corresponding to the rib-shaped walls 44a and 44b, is a process of laminating. Therefore, their heights after formation are substantially uniform as shown in FIG. However, in general, the printing of the phosphor paste for forming the phosphor layer 20 is performed in a relatively early stage in which the lamination height is about the thickness of the phosphor layer 20 to be formed in the process of forming the rib-shaped wall 44. This is performed, for example, when printing about two layers of thick film insulating paste. Therefore,
As shown in FIG. 8, since a large step dh remains at that time, the top of the lower layer, that is, the top of the paste layer 62 corresponding to the rib-like wall 44a and the non-opening (emulsion) 64b of the screen 64 are formed. Is insufficient, and the phosphor paste is likely to spread on the top, so that the mutually adjacent phosphor layers 20, 20 are considered to be brought into contact as shown in the center of the figure. Thus, the phosphor layer 2
When the 0 and 20 are brought into contact, the anodes 40 and 40 (ie, independently driven different electrodes) electrically separated by the rib-shaped wall 44a are short-circuited through the phosphor layers 20 and 20. The problem described above occurs.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to manufacture an anode substrate of a fluorescent display tube having two types of rib-shaped walls having different protruding surfaces. It is an object of the present invention to provide a manufacturing method capable of suitably suppressing dripping of a lower portion of a rib-like wall formed on an anode and contact of a phosphor layer on a rib-like wall standing on the same plane as the anode.

[0008]

In order to achieve the above object, the gist of the present invention is to provide a plurality of anodes, a phosphor layer fixed on the anodes, and a phosphor layer in a vacuum space. A control electrode provided on the top of a rib-like wall protruding higher than the phosphor layer at a position surrounding the phosphor layer in order to control electrons generated from a cathode provided above the body layer. And a display surface to which a plurality of anodes are fixed, and the rib-like wall has a first rib-like wall erected on the same plane as the fixing surface of the plurality of anodes and a second rib-like wall erected on the plurality of anodes. A method for manufacturing an anode substrate of a fluorescent display tube including two rib-shaped walls, wherein (a) an anode for forming the plurality of anodes by printing a predetermined thick film conductor paste on the display surface After the forming step and (b) the anode forming step, a predetermined thick film insulating paste is formed. A first paste forming a lower paste layer for forming a lower portion of the first rib-like wall by screen-printing with a pattern of the first rib-like wall so as to have substantially the same height as the plurality of anodes. A rib-shaped wall lower part forming step, and (c) repeatedly printing and drying the thick film insulating paste on the anode and the lower paste layer with the pattern of the first rib-shaped wall and the second rib-shaped wall. By laminating and further firing, a rib-like wall forming step of simultaneously forming the first rib-like wall and the second rib-like wall at a predetermined height, and (d) during the execution of the rib-like wall forming step or A phosphor layer forming step of forming the phosphor layer by printing a predetermined phosphor paste on the anode after implementation.

[0009]

In this way, in the anode forming step, a plurality of anodes are formed by printing a predetermined thick film conductor paste on the display surface, and then in the first rib-like wall lower part forming step. A lower paste layer for forming a lower portion of the first rib-like wall by screen-printing the thick film insulating paste in a pattern of the first rib-like wall so as to have a height substantially similar to those of the plurality of anodes. Is formed, in a subsequent rib-like wall forming step, the thick-film insulating paste is repeatedly screen-printed and dried on the anode and the lower paste layer in a pattern of the first rib-like wall and the second rib-like wall, and laminated, By baking, the first rib-like wall and the second rib-like wall are simultaneously formed at a predetermined height, and further, during or after the rib-like wall forming step,
In the phosphor layer forming step, a phosphor layer is formed by printing a predetermined phosphor paste on the anode. Therefore, in the first rib-like wall lower part forming step, the lower paste layer constituting the lower part of the first rib-like wall formed on the same plane as the anode among the rib-like walls provided on the display surface is substantially the same as the anode. A thick film insulating paste for forming the first rib-like wall and the second rib-like wall, respectively, is simultaneously printed and laminated on the lower paste layer and the anode. Therefore, in the rib-like wall forming step for simultaneously forming the first rib-like wall and the second rib-like wall, the height position at which the thick film insulating paste is applied to form them is substantially uniform in advance. Because they are aligned,
Since the appropriate printing conditions are the same, dripping of the lower part of the rib-like wall due to excessive application of the thick film insulating paste on the anode is suitably suppressed. Further, the phosphor layer forming step is performed after the height positions at which the thick film insulating paste for forming the first rib-shaped wall and the second rib-shaped wall are applied are aligned, that is, the phosphor layer forming position. Is performed during or after the rib-like wall forming step with the rib-like walls having a uniform height or a paste layer for forming the rib-like walls provided around the rib-like walls. The contact of the phosphor layer caused by the above is also suitably suppressed.

[0010]

In another embodiment of the present invention, the phosphor layer forming step is preferably carried out in a state where the thick film insulating paste is applied only in the rib-like wall forming step. With this configuration, the phosphor paste is applied in the phosphor layer forming step with only one thick film insulating paste applied in the rib-shaped wall forming step. That is, in the phosphor layer forming step, in the rib-like wall forming step,
The second layer of the paste layer for forming the first rib-like wall on the lower paste layer, that is, between the anodes, and the first layer of the paste layer for forming the second rib-like wall on the anode are formed by coating. It is performed in the state where it was done. Therefore, there is an advantage that the thickness of the applied phosphor paste is reduced to about one thickness of the thick film insulating paste for forming the rib-shaped walls, and thus the phosphor layer can be formed thin. In general, only about several (μm) to several tens (μm) of the electron incident side surface layer contribute to light emission in the entire thickness of the phosphor layer. On the other hand, since the phosphor, which is an oxide, has a high specific resistance, when its thickness is excessively large, the flow of electrons from the surface layer to the anode located thereunder is hindered, and charges are accumulated in the surface layer portion. In addition, the negative electric field formed by the accumulated charges hinders the incidence of electrons, hinders light emission and reduces the brightness.
Also, an excessive thickness of the phosphor layer is not preferable in terms of manufacturing cost. Therefore, it is desirable that the thickness of the phosphor layer is so thin that the entire thickness range contributes to light emission.

According to the conventional substrate manufacturing method, the paste layer for forming the first rib-like wall standing on the same surface as the anode protrudes beyond the anode, so that the range of application of the phosphor paste is divided. As described above, when the paste layer is formed in two layers, the paste layer for forming the second rib-like wall located on the anode is also formed in two layers. Therefore, the phosphor layer formed in that state was as thick as the thickness of two paste layers substantially equal to the thickness of the second rib-like wall. On the other hand, according to the above aspect, when one layer of the thick film insulating paste is applied in the rib forming step, only one layer of the paste is formed on the anode, and thus the phosphor paste applied in that state is used. The thickness becomes even more.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the drawings. In the following description, the dimensional ratios and the like of each part are not necessarily drawn accurately.

FIG. 1 is a partially cutaway perspective view showing a fluorescent display tube 10 to which a method of manufacturing an anode substrate according to an embodiment of the present invention is applied. In the figure, a fluorescent display tube 10 has a phosphor layer 20 _S , which will be described later, formed in a predetermined emission pattern,
20 _D, 20 _N glass having a plurality of locations, and ceramics, and an insulating material made of substrate 12 such as enamel, and glass spacers 14 formed in a frame shape, a transparent cover glass plate 16, a plurality A plurality of anode terminals 18 _P , a plurality of grid terminals 18 _G , a cathode terminal 18 _K , and an auxiliary grid terminal 18 _SG are provided, and the substrate 12, the spacer 14, and the cover glass plate 16 are mutually glass-sealed. By being attached, a vacuum space surrounded by those members is formed.

The surface of the substrate 12 covered by the vacuum space functions as a display surface of the fluorescent display tube 10, and includes a plurality of phosphor layers each having a seven-segment "8" character shape. 20 _S , one phosphor layer 20 _D representing a dot shape, and one phosphor layer 20 _N representing a “1” character shape
Are arranged to constitute light emission units for displaying each character and the like. Each of the phosphor layers 20 _S , 2
0 _D and 20 _N are respectively surrounded by grid electrodes 22 provided for each light emitting unit.
2 is further surrounded by an auxiliary grid electrode 24 which is electrically insulated therefrom. The auxiliary grid electrode 24 is provided in common on the entire display surface. Of the above-mentioned phosphor layers 20 _S , 20 _D , and 20 _N , those having a predetermined position for each display digit are connected to each anode terminal 18 _P via an anode printed wiring 34 described later. Each grid electrode 22 is connected to each grid terminal 18 _G via a grid wiring 26, and each auxiliary grid electrode 24 is connected to each auxiliary grid terminal 18 _SG via an auxiliary grid wiring 28.

[0015] On both ends of the substrate 12, the cathode terminal 18 a pair of filament support frame 30 having a _K are fixed respectively, between which the filament support frame 30, directly-heated cathode (cathode)
A thin filament 32 functioning as a wire is stretched so as to be at a predetermined height position parallel to the longitudinal direction of the substrate 12 and separated from the display surface of the substrate 12.

Therefore, the thermoelectrons emitted from the filament 32 are accelerated by the grid electrode 22 to which a positive voltage (acceleration voltage) of about 20 (V) is applied to the zero (V) filament 32, for example. Therefore, when a positive voltage is also applied to the phosphor layer 20 surrounded by the grid electrode 22, thermions collide with the phosphor layer 20 to cause the phosphor layer 20 to emit light. Even if a positive voltage is applied to the body layer 20, a negative bias voltage (cutoff bias = negative erase voltage) of about several (V) is applied to the filament 32 to the grid electrode 22 surrounding it. The thermal electrons do not reach the phosphor layer 20 and
Does not emit light. Accordingly, in a state where the thermoelectrons are emitted by the current flowing through the filament 32, in synchronization with the sequential application of the positive voltage to the grid electrode 22, the phosphor layers _20S , _20D , When a positive voltage is also applied to a desired one of the 20 _N , light-emitting display is performed in a desired pattern by so-called dynamic driving.

At this time, although a cutoff bias is applied to the grid electrode 22 to which no acceleration voltage is applied, a common auxiliary grid electrode 24 has a positive voltage similar to the acceleration voltage applied to the grid electrode 22, for example. A voltage (auxiliary acceleration voltage) is constantly applied to make the potential constant. That is, the grid electrode 22 to which the acceleration voltage has been applied is surrounded by the auxiliary grid electrode 24 to which the auxiliary acceleration voltage has been applied. Therefore, the negative electric field formed by the grid electrode 22 to which the cutoff bias is applied is canceled by the auxiliary grid electrode 24. Thus, the electron flow toward the desired phosphor layers 20 _S , 20 _D , and 20 _N to be emitted is not disturbed by the negative electric field, and the emission unevenness of the phosphor layer 20 is suitably suppressed. Therefore, in this embodiment, the grid electrode 22 and the auxiliary grid electrode 24 correspond to control electrodes.

Hereinafter, the fluorescent display tube 10 of the substrate 12 will be described.
FIG. 2 is an enlarged view of a portion showing a phosphor layer _20S having a character shape of “8”, which is one of the light emitting units (display patterns) of FIG. 2, and FIG. 3 is a sectional view taken along line III-III of FIG. Next, the electrode structure on the substrate 12 will be described in detail. In the drawing, on the display surface of the substrate 12, for the anode as thick film conductor paste is connected to the anode terminal 18 _P by firing printed to a thickness of about 15 ([mu] m) by screen printing and A printed wiring 34 is formed, on which an insulator layer 38 having a predetermined thickness and appropriately provided with a through hole 36 penetrating in the thickness direction is fixed. The insulator layer 38 is made of a thick film insulating paste containing a low-melting glass and a coloring pigment, which is formed by screen printing at 30 to 40 μm.
m) is applied and fired to a thickness of about m). Note that the wiring 34 may be provided by etching an aluminum thin film, for example, instead of being provided by screen printing.

On the insulator layer 38, the phosphor layer 20
A graphite layer 40 having a pattern similar to that of _S but having a slightly larger pattern is formed at a position where the graphite layer 40 is electrically connected to the anode printed wiring 34 via the through hole 36. The graphite layer 40 is formed by printing and firing a thick film conductor paste containing graphite as a main component in a predetermined pattern so as to have a thickness of about 30 (μm).
Functions as an anode. In the present embodiment, strictly speaking, the phosphor layer 2 having the “8” character shape in the graphite layer 40
The portion located directly below 0 _S functions as an anode, and the portion 42 protruding from the “8” character-shaped phosphor layer 20 _S to the outer peripheral side functions as an outer peripheral electrode. The above-mentioned phosphor layer 20 _S is formed, for example, by printing a thick-film phosphor paste on the graphite layer 40.

Further, at the same time on the periphery of the phosphor layer 20 _S, the rib-shaped wall 44 of and encircled state in contact with the outer peripheral edge thereof it is erected by being printed thick film dielectric paste, its fluorescence The auxiliary rib-like wall 4 which is separated from the outer peripheral edge of the graphite layer 40 located below the body layer 20 _{S by} a small distance (that is, substantially contacts the outer peripheral edge) and surrounds it.
6 stands on the insulator layer 38 at a predetermined interval on the outer peripheral side of the rib-shaped wall 44. As shown in the center of FIG.
6, a first rib-shaped wall 44a protruding from the insulator layer 38, and a second rib-shaped wall protruding from the graphite layer 40 as shown on both sides of the first rib-shaped wall 44a. There are two types, the wall 44b. Second rib-like wall 44
b is for the purpose of forming the graphite layer 40 so as to protrude to the outer peripheral side as described above, so that the outer peripheral edge portion functions as the outer peripheral electrode 42.
0. On the other hand, the first rib-shaped wall 44a provided at the boundary between the adjacent segments is provided with the insulator layer 3 for the purpose of preventing short-circuiting between segments as different electrodes.
8, that is, on the same plane as the graphite layer 40. In other words, the rib-shaped wall 44 is provided at a portion other than the boundary between the segments, that is, at a portion where it is not necessary to prevent a short circuit between different electrodes, such as between the phosphor layer 20 and the auxiliary rib-shaped wall 46. The second rib-shaped walls 44b projecting from the graphite layer 40 are all provided.
It has been. The first rib-like wall 44a protruding from above the insulator layer 38 is separated from the graphite layer 40 by a small distance, similarly to the auxiliary rib-like wall 46. That is, the graphite layer 40 is similarly formed on the insulator layer 3.
At a slight distance from all the first rib-like walls 44a and the auxiliary rib-like walls 46 provided on the upper surface 8, they are not in contact with them. Therefore, a part of the phosphor layer 20 fixed on the graphite layer 40 enters the gap between the first rib-like wall 44a and the graphite layer 40 and is brought into contact with the insulator layer 38. In this embodiment, the first rib-like wall 44a and the auxiliary rib-like wall 46 correspond to the first rib-like wall in the claims.

The first rib-like wall 44a and the second rib-like wall 4
4b (hereinafter referred to as the rib-shaped wall 44 unless otherwise required) and the auxiliary rib-shaped wall 46
By printing a thick film insulating paste composed of an insulating material such as a low melting point glass or an inorganic filler a plurality of times by thick film screen printing, for example, W = 120 to 150 (μ)
a width of about m) one hundred to twelve than the phosphor layer 20 _S
0 (μm), and the distance between the rib-like wall 44 and the auxiliary rib-like wall 46 is, for example, D
= About 120 to 150 (μm). The grid electrode 22 and the auxiliary grid electrode 24 are simultaneously formed on the tops of the rib-shaped wall 44 and the auxiliary rib-shaped wall 46 by printing a thick film conductive paste. These grid electrode 22 and auxiliary grid electrode 24
Are made of thick film conductors each having a thickness of about 10 to 50 (μm) mainly composed of a metal material (particulate conductive substance) such as silver, palladium, copper, aluminum, nickel or the like. The grid electrode 22 and the auxiliary grid electrode 24 are formed on the insulator layer 38 by thick film printing.
_Are connected to the grid terminal 18 _G and the auxiliary grid terminal 18 _SG , respectively.

FIGS. 5 (a) to 5 (c) show a method of manufacturing the substrate 12 (anode substrate) configured as described above, showing a process chart of FIG. 4 and a cross section corresponding to FIG. 3 at each stage of the process. This will be described with reference to FIG. First, after providing the anode printed wiring 34 and the insulator layer 38 on the substrate 12, an S layer printing step S1 is performed.
Then, a graphite paste (thick film conductor paste) for forming the graphite layer 40 is applied on the insulator layer 38 in a pattern of the graphite layer 40. As the graphite paste, one obtained by dispersing graphite or resin in a solvent and adjusting the viscosity to a predetermined value is used. In addition, in all of the following steps, the paste is applied using a thick film screen printing method,
Other methods are acceptable. Further, when the coating thickness is insufficient in one printing, the printing is repeated so as to obtain an appropriate thickness. Next, a baking treatment is performed in the baking step S2 to form the graphite layer 40 on the substrate 12 (strictly, on the insulator layer 38) with a thickness of about 30 (μm). In this embodiment, the S-layer printing step S1 and the baking step S2 correspond to an anode forming step.

In the subsequent first insulating paste printing step S3, the first rib-like wall 44a and the auxiliary rib-like wall 46 are formed.
The insulator layer 3 is formed using a screen 50 for forming
8, that is, on the same surface as the fixed surface of the graphite layer 40, the corresponding first layer 56 a of the paste layer 56 has a thickness of about 30 (μm), that is, the graphite layer 40. It is formed in the same thickness as that described above. Further, in the drying step S4, the paste layer 56a formed by coating is dried to remove the solvent in the paste and harden the paste layer 56a. FIG.
(a) shows this state. As the thick-film insulating paste, one obtained by dispersing a low-melting glass, an inorganic filler, a resin, and the like in a solvent and adjusting the viscosity to a predetermined value is used. The thickness of one layer of the thick film insulating paste is usually 15
In this step, a so-called drop-in printing is performed, so that a large coating thickness can be obtained. As a result, the surface of the first layer 56a is located at the same height position as the graphite layer 40. In other words, the first layer 56a for forming the first rib-like wall 44a and the auxiliary rib-like wall 46 is formed by application under appropriate printing conditions such that such an application thickness is obtained. Further, FIG.
(c) shows the opening pattern of each of the screens 50, 52 and 54 used in each step above the substrate 12 shown in FIG. 5 (a) used in the first insulating paste printing step S3. Screen 50 is provided with a first rib-shaped wall 44.
a and an opening 50a corresponding to the position where the auxiliary rib-like wall 46 is formed. That is, the screen 50 is for forming the rib-shaped walls 44 and 46, and as apparent from comparison with the screen 52 described later, the emulsion is fixed at the position corresponding to the second rib-shaped wall 44b. A non-opening portion (emulsion portion) 50b remains as it is. In this embodiment, the first insulating paste printing step S3
And the drying step S4 corresponds to a first rib-shaped wall lower part forming step. Therefore, the first layer 56a formed by applying one layer of the thick film insulating paste is referred to as a “lower paste layer”.
Is equivalent to

In the second insulating paste printing step S5, the first insulating paste is printed on the graphite layer 40 and the first layer 56a by using the screen 52 for forming the rib-like wall 44 and the auxiliary rib-like wall 46. The same thick film insulating paste as in step S3 is applied to a thickness of about 15 to 20 (μm). Thereby, the second layer 56b of the paste layer 56 corresponding to the first rib-like wall 44a and the auxiliary rib-like wall 46,
And a paste layer 58 corresponding to the second rib-shaped wall 44b.
Is formed. Then, by performing a drying treatment in the drying step S6 in the same manner as in the drying step S4, the solvent in the paste is removed, and the second layer 56b and the first layer 58a are cured. FIG. 5B shows this state. The screen 52 has a first rib-shaped wall 44
a, an opening 52a is formed at a position corresponding to the second rib-shaped wall 44b and the auxiliary rib-shaped wall 46, and in this step, the second rib-shaped not applied in the first insulating paste printing step S3. The thick film insulating paste is also applied to the position corresponding to the wall 44b. That is, the second rib-like wall 44b
Is not formed at the position corresponding to the first layer 56a, and the first layer 58a corresponding to the second layer 56b is formed directly on the graphite layer 40. At this time, since the previously formed first layer 56a has the same thickness as the graphite layer 40, the heights of the application surfaces of the second layer 56b and the first layer 58a formed thereon are respectively: Become uniform. Therefore, the thick-film insulating paste is applied under appropriate printing conditions to any application position corresponding to each of the first rib-like wall 44a and the second rib-like wall 44b, and the second layer 56b and the second The surface of each layer 58a is located at a similar height. Therefore, at the position where the second rib-shaped wall 44b is formed, the paste spreads as shown in FIG. 7 and no rib drooping occurs, and the first layer has a size substantially equal to the width dimension of the opening 52a. 58a are formed.

In the phosphor paste printing step S7,
Using a screen 54 for forming the phosphor layer 20, a thick-film phosphor paste is applied to a predetermined position on the graphite layer 40, and in a subsequent drying step S8, the solvent in the paste is dried and removed. As the thick film phosphor paste, one obtained by dispersing phosphor powder, resin, and the like in a solvent and adjusting the viscosity to a predetermined value is used. Thus, the phosphor powder in the thick-film phosphor paste is fixed on the graphite layer 40 to form the phosphor layer 20. Fig. 5 (c)
Indicates this state. At this time, since the tops of the second layer 56b and the first layer 58a are located at the same height as described above, as shown in the figure, the phosphor layer 20 has its surface flush with those surfaces. It is formed so as to be located above. As a result, the thickness of the phosphor layer 20 is the same as that of the first layer 58a on the graphite layer 40, that is, 15 to 20 (μm) which is equal to the thickness of one layer of the thick film insulating paste.
It is about. Moreover, the graphite layers 40, 40 shown in two places in the figure, that is, the phosphor layers 20, 20 formed on the different electrodes, respectively, are surely separated by the second layer 56b of the paste layer 56 located in the center of the figure. Therefore, the phosphor layers 20, 20 do not come into contact with each other. The screen 54 has an opening 54 a at a position corresponding to the phosphor layer 20.
Phosphor layers 2 of two or more different emission colors on the display surface 2
In the case where 0 is provided, a plurality of screens 5 corresponding to the number of colors provided with openings 54a at different positions for each color are provided.
4, and the phosphor paste printing step S7 and the drying step S8 are repeated by that number. In this embodiment, the phosphor paste printing step S7 and the drying step S8 correspond to a phosphor layer forming step.

After forming the phosphor layer 20 as described above, a third insulating paste printing step S9 and a drying step S1
At 0, using the same screen 52 as that used in the second insulating paste printing step S5, the above-mentioned thick film insulating paste is applied on the second layer 56b and the first layer 58a, and drying is repeated. . The number of repetitions is appropriately set so that the heights of the rib-shaped wall 44 and the auxiliary rib-shaped wall 46 are obtained. Thus, the paste layer 5
After the formation of 6, 6 and 58, baking is performed at a predetermined temperature to form the rib-like wall 44 and the auxiliary rib-like wall 46 from these paste layers 56 and 58. In the present embodiment, the second insulating paste printing step S5, the drying step S6, the third insulating paste printing step S9, the drying step S10, and the subsequent baking step correspond to a rib-like wall forming step. Therefore, the phosphor layer forming step is performed during the rib-shaped wall forming step.

According to this embodiment, in the S-layer printing step S1 and the baking step S2, a plurality of graphite layers 40 are formed by screen-printing and baking graphite paste on the display surface of the substrate 12. Then, the first insulating paste printing step S3 and the drying step S
4, the first rib-shaped insulating paste is screen-printed in the pattern of the first rib-shaped wall 44a and the auxiliary rib-shaped wall 46 so as to have substantially the same height as the plurality of graphite layers 40. First layer 56a for forming the lower part of the wall 44a and the auxiliary rib-like wall 46
Is formed, followed by a second insulating paste printing step S5, a drying step S6, a third insulating paste printing step S9, and a drying step S
10, and in the firing step, the thick-film insulating paste is repeatedly screen-printed, dried and laminated on the graphite layer 40 and the first layer 56a, and further fired, whereby the first rib-shaped wall 44a, the second rib-shaped The wall 44b and the auxiliary rib-like wall 46 are simultaneously formed at a predetermined height,
Further, the phosphor layer 20 is formed by printing the phosphor paste on the graphite layer 40 in the phosphor paste printing step S7 and the drying step S8 during the process of forming the rib-shaped walls 44 and the like.

Therefore, of the rib-like wall 44 and the auxiliary rib-like wall 46 provided on the display surface of the substrate 12, the first rib-like wall 44a formed on the same plane as the graphite layer 40
After the first layer 56a for forming the lower part of the first layer is formed at substantially the same height as the graphite layer 40, the thick film insulating for forming the first rib-like wall 44a and the second rib-like wall 44b, respectively. The paste is simultaneously printed and laminated on the first layer 56a and the graphite layer 40. Therefore, in each step for simultaneously forming the first rib-like wall 44a and the second rib-like wall 44b, the height positions at which the thick film insulating paste is applied to form them are substantially uniform in advance. Since the distance between the screen 52 and the application surface (the surface of the first layer 56a and the surface of the graphite layer 40) is uniform and their appropriate printing conditions are the same, the thickness on the graphite layer 40 is reduced. The dripping of the lower part of the rib-shaped wall 44 due to excessive application of the film insulating paste is suitably suppressed. That is, the first layer 56
a, and also when the second layer 56b and the first layer 58a are formed by printing.
The amount of paste discharged from the openings 50a and 52a can be set to an appropriate amount. This makes it clear from comparison between FIG. 5C and FIG. 8 that a part of the rib-like wall 44 does not exist between the phosphor layer 20 and the graphite layer 40 at the periphery of the pattern. For example, in the pattern of the rectangular phosphor layer 20 as shown in FIG. 6A, a decrease in the luminance at the peripheral portion as shown in FIG. 3.) Uniform brightness is obtained, and display quality is improved.

In the step of forming the phosphor layer 20, the height positions at which the thick film insulating paste for forming the first rib-shaped walls 44a and the second rib-shaped walls 44b are applied are aligned, ie, This is performed during the formation of the rib-shaped wall 44 in a state where the paste layers 56 and 58 for forming the phosphor layers 20 are provided at uniform heights around the formation position. Therefore, the non-opening portion 54b of the screen 54
And a paste layer 56 for forming the first rib-like wall 44a
Of the phosphor layer 20 due to the spread of the phosphor paste on the second layer 56b or the back surface of the non-opening portion 54b (the paste discharge surface, ie, Wrapping around the paste layer 56) is suitably suppressed. Therefore, the leakage failure due to the contact is suppressed, the manufacturing yield is improved, and the phosphor paste attached to the back surface of the non-opening portion 54b is wiped to prevent bleeding during printing.
There is also an advantage that the frequency of manufacturing can be reduced and the number of manufacturing steps can be reduced.

In this embodiment, the rib-like wall 44
The phosphor paste for forming the phosphor layer 20 is applied while only one thick film insulating paste is applied in the forming step. That is, in the step of forming the phosphor layer 20, the second layer 56 b of the paste layer 56 for forming the first rib-shaped wall 44 a on the first layer 56 a, that is, between the graphite layers 40 in the step of forming the rib-shaped wall 44. However, the first layer 58a of the paste layer 58 for forming the second rib-like wall 44b on the graphite layer 40 is applied and formed. Therefore, the thickness of the applied phosphor paste is reduced to about one layer of the thick film insulating paste for forming the rib-shaped wall 44, and the phosphor layer 20 is extended to about 15 to 20 (μm). Because it is thin,
There is an advantage that the amount of charge accumulated on the surface of the phosphor layer 20 due to the intrinsic resistance of the phosphor is reduced, so that higher luminance can be obtained and the manufacturing cost is reduced.

Although the embodiment of the present invention has been described in detail with reference to the drawings, the present invention can be applied to other embodiments.

For example, in the embodiment, while the first layer 58a is formed on the graphite layer 40, the phosphor paste is applied on the graphite layer 40. It is changed as appropriate according to the thickness and the like. For example, when the phosphor layer 20 is formed to be thicker than the embodiment, the phosphor paste may be applied when the paste layer 58 is laminated to the same thickness.

In the embodiment, the first layer 56a is formed at the same height as the graphite layer 40, so that the application surfaces of the second layer 56b and the first layer 58a are made uniform. The height of the application surface may have a certain level difference. That is, even if the printing conditions of one of the second layer 56b and the first layer 58a are not optimal when the other printing conditions are not optimal, no dripping of ribs, no chipping of the pattern, or the like occurs, or they occur. If the first layer 56a is formed to be slightly higher or slightly lower than the graphite layer 40, the effect of the present invention can be obtained because the function of the fluorescent display tube 10 is not hindered if negligible. . In short, in order to obtain the effect of the present invention, in the first rib-shaped wall lower part forming step (first insulating paste printing step S3), the first layer 56a applied and formed on the same surface as the fixed surface of the graphite layer 40 is formed. It suffices if the height is substantially the same as the graphite layer 40.

In the embodiment, the phosphor layer 20 is formed during the formation of the rib-shaped wall 44. However, the phosphor layer 20 may be formed after the rib-shaped wall 44 is fired. In this case, the phosphor layer 20 is formed in a desired thickness by applying the phosphor paste to a predetermined position by so-called dropping.

In the embodiment, the grid electrode 2
2, an auxiliary grid electrode 24 was provided around
The auxiliary grid electrode 24 may be provided double or triple or more. Conversely, the present invention is similarly applied to a case where the auxiliary grid electrode 24 is not provided if there is no problem in display.

The auxiliary rib-shaped walls 46 which are not located between the graphite layers 40 need not necessarily be formed in the same step as the first rib-shaped walls 44a. At the position where such an auxiliary rib-shaped wall 46 is formed, the adhesion between the screen and the substrate 12 is not so low as between the graphite layers 40 when the first layer 56a is printed. Therefore, in the second insulating paste printing step S5 of applying and forming the second layer 56b and the first layer 58a that are set so that the printing conditions on the graphite layer 40 are appropriate, the first layer 56a at that position is removed. It is possible to print at the same time. That is,
Rib-shaped wall 4 located at least between graphite layers 40
4a and the first layer 5 for forming the auxiliary rib-like wall 46
If 6a is applied and formed in the first insulating paste printing step S3, the effects of the present invention can be obtained.

Further, in the embodiment, the graphite layer 40 is slightly separated from the rib-like wall 44a and the auxiliary rib-like wall 46. However, the present invention can be applied to a case where these are provided in contact with each other. Applies analogously.

The above description is merely an embodiment of the present invention, and the present invention can be variously modified without departing from the gist of the present invention.

[Brief description of the drawings]

FIG. 1 is a partially cutaway perspective view showing a fluorescent display tube to which a manufacturing method according to an embodiment of the present invention is applied.

FIG. 2 is a plan view showing a main part of a display surface of a substrate of the fluorescent display tube of FIG.

FIG. 3 is a sectional view taken along the line III-III of FIG. 2;

FIG. 4 is a process diagram illustrating a main part of a manufacturing process of the fluorescent display tube of FIG. 1;

5 (a) to 5 (c) are diagrams illustrating a cross-sectional structure of a substrate at each stage of the manufacturing process in FIG.

6 (a) is a diagram for explaining a light emitting state of the phosphor when the manufacturing process of FIG. 4 is followed, and FIG. 6 (b) is a diagram for explaining the case of a conventional manufacturing process.

FIG. 7 is a diagram illustrating a problem of a conventional manufacturing process.

FIG. 8 is a view for explaining another problem of the conventional manufacturing process.

[Explanation of symbols]

12: substrate 20: phosphor layer 40: graphite layer (anode) 56: paste layer, 56a: first layer (lower paste layer), 56b: second layer 58b: first layer

Continuation of front page (56) References JP-A-8-287853 (JP, A) JP-A-8-138590 (JP, A) JP-A-7-85792 (JP, A) JP-A-7-57630 (JP) , A) (58) Field surveyed (Int.Cl. ⁷ , DB name) H01J 9/14 H01J 9/227 H01J 31/15 H01J 9/24

Claims (2)

(57) [Claims] 1. A method for controlling electrons generated from a plurality of anodes, a phosphor layer fixed on the anode, and a cathode provided above the phosphor layer in a vacuum space. A display surface to which a control electrode provided on the top of a rib-like wall protruding higher than the phosphor layer is fixed at a position surrounding the phosphor layer, and the rib-like wall is provided with a plurality of anodes; A method for manufacturing an anode substrate of a fluorescent display tube of a type including a first rib-like wall erected on the same surface as a fixing surface and a second rib-like wall erected on the plurality of anodes. An anode forming step of forming the plurality of anodes by printing a predetermined thick film conductor paste on the display surface; and after the anode forming step, applying a predetermined thick film insulating paste to the first rib-like wall. Screen printing so as to have the same height as the plurality of anodes in the pattern of Forming a lower paste layer for forming a lower portion of the first rib-shaped wall, and forming a lower portion of the first rib-shaped wall on the anode with a pattern of the first rib-shaped wall and the second rib-shaped wall. The first rib-shaped wall and the second rib-shaped wall are simultaneously formed at a predetermined height by repeatedly screen-printing, drying and laminating the thick film insulating paste on the lower paste layer, and further firing. And a phosphor layer forming step of forming the phosphor layer by printing a predetermined phosphor paste on the anode during or after the rib wall forming step. A method for manufacturing an anode substrate of a fluorescent display tube, characterized by comprising: 2. The method for manufacturing an anode substrate of a fluorescent display tube according to claim 1, wherein the phosphor layer forming step is performed in a state where the thick film insulating paste is applied only in one layer in the rib-shaped wall forming step.