JPH02181340A - Formation of dot array fluorescent tube - Google Patents

Abstract

PURPOSE:To unify the dot size of a phosphor surface and stabilize luminous brightness by setting-up a process for performing from an electrode formation process to a phosphor face formation preprocess under the integrated circumstances. CONSTITUTION:Recessed parts 22 are provided in an array on the surface of a substrate 20, these respective recessed parts 22 are stuck with a conductive material respectively to form segment electrodes 23 and to form an insulating film 24 on the surface of the substrate 20 followed by exposing the segment electrodes 23 in a dotted shape in the positions to form phosphor surfaces 26 to be stuck with phosphors. For performing a segment electrode 23 array. Next, phosphor particles are stuck to the positions to form phosphor surfaces 26 of the exposed segment electrodes 23 to set up grid electrodes 27 on an insulating layer 24. Thereby, the dot size of the phosphor surface 26 can be uniformly and with good accuracy formed while getting rid of disunity of luminous brightness of the phosphor surface 26.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for forming a dot array fluorescent tube suitable as a fluorescent display tube or a barcode display tube.

(Prior Art) The structure of a dot array fluorescent tube will be explained with reference to FIGS. 9 and 10. In these figures, reference numeral 1 indicates a substrate made of plate-shaped glass or ceramics. On the surface of this substrate 1, segment electrodes 2 are arranged in rows at intervals in the longitudinal direction.

Insulating layers 3, 3 are formed on both longitudinal edges of the substrate 1, and grid electrodes 4, 4 are provided on the upper surface thereof. A face glass 5 is fixed on the grid electrodes 4, 4, and the substrate, the insulating layer, and the face glass constitute a vacuum space. A filament 6.6 is stretched in this space,
A fluorescent screen 7 is formed on the segment electrode 2 . Therefore, when looking into the inside of the tube through the face glass 5, one can see 110 that the fluorescent screens 7 are lined up in a dot shape.

A method for forming such a dot array fluorescent tube will be explained based on FIGS. 11 and 12. In the electrode formation process,
Segment electrodes 2 made of a conductive material such as aluminum are formed in rows on the surface of a substrate 1 made of a glass plate by photoetching. In the insulating layer forming step, a thick insulating glass made of thick film insulating glass, such as lead glass and carbon, is formed so as to cover the side edges of the segment electrodes 1 in the substrate width direction, in other words, so that the central part of the electrodes 2 is exposed. 1
Both side edges of the substrate are covered with an insulating layer 3 having a thickness of about 0 to 20 μm. The insulating layer 3 is formed by screen printing and then fired. In the photoresist layer forming step, as shown in FIG. 12(a), the insulating layer 2. The entire segment electrode 2 is covered with a photoresist layer 8 using a spinner or dipping. Next, as shown in FIG. 12(b),
The photoresist layer 8 is exposed to light through a mask 9 and then developed to form segment electrodes 2 as shown in FIG. 12(C).
Expose the fluorescent screen forming position [2a] in the center of the screen. Fluorescent screen formation position I! ! In the next step of forming a phosphor screen, the phosphor screen 7 is formed on the substrate 1 with the phosphor screen 2a exposed at the above position [2a], as shown in FIG. 12(d). The formation of the phosphor screen is performed by connecting segment electrodes 1 and screws 1 to 1, as shown in FIG.
A counter electrode 13 disposed between the substrate 2 and the substrate is connected to a power source, and the substrate 1 is immersed in a solvent 11 in which phosphor particles stored in a tank 10 are dispersed. When an electric field is applied between the segment electrode and the counter electrode and the screw 12 is rotated to stir the dispersion, the phosphor particles in the liquid electrophores to form a phosphor screen Ii! ! The phosphor screen 7 is formed by adhering and depositing on the phosphor screen 2a.

When the stirred dispersion liquid 11 flows between the counter electrode 13 and the substrate 1, it adheres to the exposed phosphor screen forming position 2a of the segment electrode 2, as shown in FIG. After forming the phosphor screen, it was dried and fixed.

In the photoresist layer removal step, the photoresist layer 8 is fired using, for example, oxygen plasma, and the core layer 8 is removed as shown in FIG. 12(a). Next, in the assembly process,
Grid electrodes 4, 4 are provided on the insulating layer 3 by appropriate means, a filament 6 is stretched using a member not shown, and then a face glass 5 is fixed to the substrate 1. After the substrate 1 and the face glass 5 are sealed in the sealing process, the inside of the dot array tube is evacuated in the exhaust process. After the exhaust is completed, proceed to the inspection process such as checking the lighting. Grid electrode 4
is provided so that the segment electrode 2 serving as an anode can efficiently capture electrons emitted from the filament 6, and has a honeycomb-like mesh structure, and is made of a conductive paste such as low-melting glass. It is installed and fixed on the insulating layer using

(Problem to be Solved by the Invention) In the process of forming the conventional dot array fluorescent tube, including the formation of the insulating layer 8, the tube is manufactured in a clean atmosphere, placed in a rough atmosphere, and then returned to the original state in a clean environment. This process requires cleaning the substrate, which leads to higher costs. In addition, the binder used during screen printing may ooze out during the segment electrode formation and phosphor screen formation processes. , C, and the like, and impairs the reliability of the quality of the pipe. Furthermore, when attempting to expose a portion of the segment electrode 2 by forming the insulating layer 8 using a screen printing method, there is a limit to the slit width. Therefore, when forming the phosphor screen, the exposed portions (2a
) must be attached with phosphor. Therefore, after forming the phosphor screen, the photoresist layer is removed using plasma! The step of removing the nosist layer is essential, and the heat treatment step, which affects the luminescence life of the phosphor, cannot be omitted. Also,
Instability of light emitting characteristics due to photoresist residue also poses a problem. Furthermore, when the phosphor particles adhere to the phosphor screen forming position 2a of the segment electrode, the phosphor screen may be formed extending beyond the position.

This protrusion does not have a large effect on the edges parallel to the arrangement direction of the segment electrodes, but when it occurs on the edges of dots perpendicular to the arrangement direction of the segment electrodes, adjacent phosphor screens are As a result, the light emitting characteristics with high precision are lost. The reality is that this "overflow" relies on the scavenging effect of the stirring flow inside the tank, and it is an extremely difficult technique to obtain a highly accurate dot size.

Next, the surface of the conventional screen-printed insulating layer 3 is
If you look at this microscopically, there are severe irregularities.Also, after the phosphor screen is formed, a separately formed grid electrode is attached to the insulating layer using a paste such as low melting point glass, so the installation of the grid electrode is required with precision. If the luminance is low, there is a problem in that luminance variations occur in the longitudinal direction of the substrate, making it impossible to obtain uniform and stable tube quality.

In addition, in the phosphor screen forming process using electrophoresis, a counter electrode is arranged at a distance from the segment electrodes. From the viewpoint of electric field, it is better for this counter electrode to be as close as possible to the phosphor screen formation position, but from the viewpoint of the electrodeposition conditions due to the fluidity of the dispersion. If you get too close.

It takes a long time to electrodeposit the phosphor particles to a desired thickness, which is not efficient. Therefore, in the past, it was difficult to set the conditions for adhesion of phosphor particles, and there was a problem that there were many variations in tube quality.

The first object of the present invention is to reduce costs by setting up the process from the electrode formation process to the pre-process of forming the phosphor screen in a clean integrated environment, and to make the dot size of the phosphor screen uniform. An object of the present invention is to provide a method for forming a dot array fluorescent tube that can stabilize luminance.

A second object of the present invention is to provide a method for forming a dot array fluorescent tube that improves the accuracy of the installation position of grid electrodes and eliminates variations in brightness.

A third object of the present invention is to provide a method for forming a dot array fluorescent tube that can improve the adhesion of phosphor particles to the fluorescent screen forming position of the segment electrode.

(Means for Solving Problem il1) The first object is to erode the surface of the substrate intermittently along the long plane direction in the electrode forming process to form a row of recesses, and to form a row of recesses in each recess. Segment electrodes are formed by attaching a conductive material, and in the insulating layer forming step, an insulating layer is formed on the substrate surface including the segment electrodes, and then the segment electrodes at the phosphor screen forming position where the phosphor is to be attached are formed into dots. to form a segment electrode row,
In the phosphor screen forming step, phosphor particles are attached to the phosphor screen forming position of the exposed segment electrode to form a phosphor screen, and in the assembly step, a grid electrode is installed on the insulating layer. This is accomplished by a dot array fluorescent tube formation method.

The second purpose is to form a grid electrode array by depositing a conductive material on the insulating layer located between adjacent segment electrodes in the grid electrode forming step after passing through the electrode forming step and the insulating layer forming step. This is achieved by a method for forming a dot array fluorescent tube, which is characterized in that, in the phosphor screen forming step, phosphor particles are attached to the exposed phosphor screen forming position of the segment electrode to form a phosphor screen.

The third purpose is to immerse the substrate in a solvent in which phosphor particles are dispersed in the phosphor screen formation step after the electrode formation step, insulating layer formation step, and grid electrode formation step, and to form the grid electrode. This is achieved by a method for forming a dot array fluorescent tube characterized in that a phosphor screen is formed by depositing phosphor particles at the phosphor screen forming position of the segment electrode using an electrophoresis method using the segment electrode as a counter electrode.

(Function) In the electrode forming step, recesses are arranged in a row on the surface of the substrate, and a conductive material is attached to each of these recesses to form a segment electrode, and in the insulating layer forming step, an insulating layer is formed on the substrate surface. After that, the segment electrodes at the phosphor screen formation position where the phosphor is to be attached are exposed in a dot shape to form a segment electrode row, and in the phosphor screen formation process, the phosphor is applied to the phosphor screen formation position of the exposed segment electrodes. Particles are deposited and a grid electrode is placed on the insulating layer in an assembly process.

In the electrode forming step, recesses are arranged in a row on the surface of the substrate, and a conductive material is adhered to each recess to form a segment electrode.In the insulating layer forming step, after forming an insulating layer on the substrate surface, fluorescent Segment electrodes at the phosphor screen forming position to which the body is to be attached are exposed in a dot shape to form a segment electrode row, and in the grid electrode forming step, a conductive material is applied on the insulating layer located between adjacent segment electrodes. The phosphor particles are attached to form a grid electrode array, and in the phosphor screen forming step, phosphor particles are attached to the phosphor screen forming positions of the exposed segment electrodes to form a phosphor screen.

In the electrode forming step, recesses are arranged in a row on the surface of the substrate, and a conductive material is adhered to each recess to form a segment electrode.In the insulating layer forming step, after forming an insulating layer on the substrate surface, fluorescent The segment electrodes at the phosphor screen forming position to which the body is to be attached are exposed in a dot shape to form a segment electrode row, and in the grid electrode forming step, a grid electrode row is formed between adjacent segment electrodes, and the phosphor screen forming step is performed. In this step, the substrate is immersed in a solvent in which phosphor particles are dispersed, and the phosphor particles are attached to the phosphor screen forming position of the segment electrodes by electrophoresis using the grid electrode as a counter electrode to the segment electrodes. Form a fluorescent screen.

(Example) Hereinafter, the present invention will be described in detail based on the illustrated example.

The first invention will be explained in order of steps based on FIGS. 1 and 2.

Electrode Formation Step 2 As shown in (a), a resist pattern 21 is formed in the width direction of a substrate 20 made of plate glass cut into a predetermined shape, exposing the portion where segment electrodes will be formed, and then As shown in FIG. 2(b), a recess 22 is formed by etching the substrate 20 by etching. According to the etching method, it is possible to form a recess with a depth of about 10 μm. As shown in FIG. 2(c), an aluminum film is deposited on the substrate surface by sputtering to form segment electrodes 23 as anode electrodes in the recesses 21.Next, as shown in FIG. 2(d), a resist film is applied. When 21 is removed, only the segment electrodes 23 formed in the recesses remain on the substrate 20.

Insulating layer forming step As shown in FIG. 2(e), as the insulating layer 24, Sio
The second film is formed as thickly as possible on the surface of the substrate by a method such as CVD (preferably photo-CVD, which causes less thermal damage to aluminum). At this time, the second
As shown in Figure (f), an insulating layer 24 is also formed on the surface of the segment electrode 23.

FIG. 2(f) shows a cross section taken along line ff in the longitudinal direction (board width direction) of the recess 22 in FIG. 2(e).
As shown in g), the insulating layer 2 is formed so that the central portion 24a of the insulating layer 24 is exposed in a line along the longitudinal direction of the substrate.
A resist layer 25 is formed on both sides of 4 by photolithography.
form a pattern. Next, as shown in FIG. 2(h), the exposed central portion 24a of the insulating layer is removed by etching to form the phosphor screen forming position 2 of the segment electrode 23.
Expose 3a. After this, the resist layer 25 is removed. When this state is viewed from above, it is as shown in FIG. 2(i). The substrate 20 shown in FIG. 2(i) is connected to the line j
When cut at the insulating layer 24.24 in the longitudinal direction at −j, the cross-sectional structure is as shown in FIG. Furthermore, when the substrate 20 shown in FIG. 2(i) is cut in its width direction, the portion where the segment electrodes 23 are provided is exposed at the phosphor screen forming position [23a], as shown in FIG. 2(k). In the area where the electrode 22 is not provided, an insulating layer 24 is formed on the thickness of the substrate before erosion. In other words, each phosphor screen forming position 23a is located one step lower than the substrate surface.

Phosphor screen forming process As shown in FIGS. 2(i) to (Q), insulating layers 24, 2
13, the substrate 20, which has been masked in step 4 to expose the phosphor screen forming position 23a of the electrode, is exposed as shown in FIG.
When immersed in a tank in which phosphor particles are dispersed, the phosphor particles in the dispersion liquid are transferred to phosphor screen formation positions [23
a to form a fluorescent screen 26 as shown in FIG. 2(m). In forming this phosphor screen 26, the phosphor screen formation position 1i23a is located one level lower than the surroundings on the substrate surface, as shown in FIG. 4 (see FIGS. 2(k) and (Q)). Since it is surrounded, the corresponding [2
The dot size of the fluorescent screen attached to 3a is uniform and accurate.

Assembly process As shown in FIG. 2(m), the substrate 2 on which the fluorescent screen 26 is formed
A grid electrode 27 is provided on the insulating layer 24.

This grid electrode 27 is made of a conductive material with a honeycomb-like mesh structure as shown in FIGS.
As shown in the figure, a filament support (not shown) is installed so as not to cover the phosphor screen 26.
Install the filament, place the face glass on the board, and fix it.

Note that this assembly process includes well-known processes such as applying a conductive paste prior to installing the grid and filament, and drying and firing after these installations, but these are omitted.

After the sealing process, exhaust process, and inspection process are completed, the substrate and face glass are tightly fixed, and then the air inside the tube is exhausted in the exhaust process. After the exhaust is completed, the dot array fluorescent tube is completed through an inspection process such as lighting confirmation.

Note that the process from the assembly process to the completion of the product includes appropriate processes, but these are omitted from the illustration.

The second invention will be explained based on FIGS. 5 to 7.

Electrode formation process/insulating layer formation process When comparing this invention with the first invention described above.

Since the steps from electrode formation to insulation layer formation are the same,
The electrode forming step and the insulating layer forming step in FIG. 5 and the corresponding explanations in FIGS. 6(a) to (e) will be omitted by giving the same reference numerals.

Grid electrode forming step The substrate 20 on which the insulating layer 24 is formed is made of a conductive material such as ITO, which will become the grid electrode, as shown in FIG. 6(f).
The layer 28 is formed by covering the entire surface by appropriate means such as sputtering. After the coating film is formed on the entire surface, the portion to become the grid electrode, that is, the substrate portion 20a left when the recess 22 was formed remains.

In other words, the ITO layer 28 above the segment electrode 23 is etched by the photophosphorography method so that the electrode 28 remains as shown in FIG. 6(g).
8 is removed and patterned. This patterning can be done by applying a resist to the entire surface of the substrate, then attaching a mask to it, and then going through the exposure and development process. However, when using a positive type resist, it is difficult to align it, so a negative type resist is used. The accuracy will be higher if you use

The ITO layer 28 is made of indium oxide doped with tin.
It is a negative type resist, and as shown in FIG. 6(f), when the lower surface of the substrate 20 is exposed, the segment electrodes 23 function as a mask, and the insulating layer 24 made of 5i02 has translucency. When developed after exposure, I
The TO layer 28 remains as shown in FIG. 6(g) except for the portion corresponding to the segment electrode 23. As shown in FIG. 7, the ITO layers 28 are connected to each other by a common line 28A located at one side edge of the substrate 20, and function as a grid electrode.

Hereinafter, the ITO layer 28 will be referred to as a grid electrode 28.

Phosphor screen forming process After applying a photoresist layer 29 to the entire surface of the substrate on which the grid electrode 28 has been formed, as shown in FIG. The core layer 29 is removed in a line in the longitudinal direction of the substrate and the resist is patterned to expose the diagonally shaded portion of the insulating layer 24 (phosphor screen forming position 23a). At this time, a part of the grid electrode 28 is also exposed.Next, by dry etching, the portion of the insulating layer 24 covering the phosphor screen forming position 23a shown with diagonal lines in FIG. 6(i) is removed. It is removed to expose the phosphor screen-shaped support [23a] as shown in FIG. 2(j). Fluorescent screen type mounting 1123a
After exposing the photoresist layer 29.29, the photoresist layer 29.29 is removed using oxygen plasma or the like. Note that FIG. 6(i) and FIG. 6(j) are plan views of the substrate. As shown in FIG. 13, the substrate with the phosphor screen forming position 23a exposed is immersed in a liquid in which phosphor particles are dispersed, and the segment electrode 23 is connected to one terminal of a power source to form the counter electrode 13. An electric field is formed between the
attached to.

As shown in FIG. 6(k), a fluorescent screen 26 is formed.

In FIG. 7, arrows indicate the flow of the dispersion during the formation of the phosphor screen. The dispersion liquid to be stirred is the W122 of the substrate 20 (
(see FIG. 6(b)), and adheres in the form of dots of a predetermined size to the phosphor screen forming position 23a, which is surrounded by walls on all sides. In FIG. 7, the phosphor screen 26 is shown to be formed only at one phosphor screen formation position 23a, but this is for convenience of explanation, and each phosphor screen shape mounting position 1123
The phosphor particles are uniformly attached to a. Fluorescent screen 26
FIG. 6 (12) is a plan view of the substrate on which the phosphor screen is formed. Note that the already formed grid electrode 28 can be used as the counter electrode when forming the phosphor screen.

This point will be explained in the third invention section.

Assembly process A filament is applied to the substrate on which the phosphor screen 26 is formed, and a face glass is installed. Since this step excludes the step of installing the grid electrode in the step explained in FIG. 1, a detailed explanation will be omitted.

Sealing process, evacuation process, and inspection process These processes are the same as those described based on FIG. 1, so their explanation will be omitted to avoid duplication.

The third invention will be explained.

This invention is characterized by the implementation of the phosphor screen forming step in the second invention explained in FIG. .

A description of the assembly process and subsequent processes will be omitted.

As shown in FIG. 6(j), the substrate with the phosphor screen forming position 23a exposed is immersed in a liquid in which phosphor particles are dispersed. At this time, segment electrode 2
3 is connected to one pole of the power supply 31, as shown in FIG. 8, and the grid electrode 28 is connected to the other pole of the power supply (with the same polarity as the dispersion liquid) at one end of the common line 28A. There is. When the dispersion liquid is stirred, the liquid is caused to flow along the recesses 22 (see FIG. 6(b)) as shown by the arrows in FIG. At this time, when the switch 32 is turned on, the phosphor particles in the dispersion liquid are transferred to the segment electrode 2.
3 and the grid electrode 28, and are electrophoresed and deposited on the phosphor screen surface [23a]. In this case, the grid electrode 28 functions as a counter electrode, and since the grid electrode 28 is positioned between adjacent segment electrodes 23, it does not impede the flow of the dispersion liquid in any way. Moreover, the phosphor screen formation position 23a is
Since the position is one step lower than the grid electrode 28, the phosphor particles are attached not only to the edge of the position 23a but also to the entire surface thereof. In addition.

The individual segment electrodes 23 of the substrate shown in FIG. 8 are connected to each other by a common line 23A, which is formed in the electrode forming process, and is formed by bringing a conductive brush into contact with each segment electrode. (Effects of the Invention) As described above, according to the first invention, the steps from the electrode formation process of the substrate to the pre-process of forming the phosphor screen are manufactured under = two environmental conditions, and the insulating layer is used for forming the phosphor screen. This improves the reliability of the manufacturing process and ensures stable quality. Further, since the segment electrodes are provided in the recesses of the substrate, the phosphor screen formation position is surrounded by a wall, and the dot size of the phosphor screen can be formed with uniformity and precision. Since there is no resist removal step after forming the phosphor screen, deterioration of the phosphor due to heat and changes in characteristics that adversely affect luminance are suppressed, and deformation such as warping of the substrate due to heat treatment is also eliminated.

According to the second invention, since the grid electrode is formed of a thin film prior to forming the phosphor screen, the positional accuracy with respect to the phosphor screen is improved, and variations in brightness of the phosphor screen are eliminated, so that a fluorescent tube of stable quality can be obtained.

According to the third invention, when forming a phosphor screen, the already formed grid electrode is used as the opposing pole, so there is no dot protrusion or backing, and the relative positions of the opposing electrode and the segment electrodes differ from device to device. Moreover, since the flow of the phosphor particles is not hindered, the phosphor particle adhesion conditions such as electrodeposition time can be kept constant at all times, and a stable phosphor screen can be formed. Furthermore, since a counter electrode is not required, the structure of the phosphor screen forming apparatus is simplified.

[Brief explanation of the drawing]

Fig. 1 is a process diagram of a dot array fluorescent tube forming method explaining the first invention, Fig. 2 is a cross-sectional view of a substrate showing the same process, and Fig. 3 is a cross-sectional view of the substrate after the grid electrode forming process is completed. , FIG. 4 is a perspective view of the substrate after the phosphor screen forming process is completed, showing only the container part, FIG. 5 is a process diagram explaining the second and third inventions, and FIG. 6 is a cross section of the substrate showing the same process as above. diagrams and plans,
Fig. 7 is a perspective view showing only the essential parts of the substrate after forming the phosphor screen, Fig. 8 is a perspective view of the main part showing the substrate during the phosphor screen forming process in the third invention, and Fig. 9 is a conventional dot array fluorescent tube. FIG. 10 is a sectional view of the same as above, FIG. U is a process diagram showing the process of forming a conventional dot array fluorescent tube, FIG. The figure is a sectional view showing an example of a phosphor screen forming apparatus, and FIG. 14 is a sectional view showing the flow of a dispersion liquid to a phosphor screen forming position. DESCRIPTION OF SYMBOLS 11... Solvent, 13... Counter electrode, 20... Substrate, 22... Recessed part, 23... Segment electrode, 23a
... Phosphor screen formation position, 24... Insulating layer, 26...
Fluorescent screen, 27.28...grid electrode.

Claims (1)

[Claims] 1. In the electrode forming step, the surface of the substrate is intermittently eroded along its longitudinal direction to form a row of recesses, and a conductive material is adhered to each of these recesses to form a segment electrode. In the insulating layer forming step, an insulating layer is formed on the surface of the substrate including the segment electrodes, and then the segment electrodes at the phosphor screen forming position where the phosphor is to be attached are exposed in a dot shape to form segment electrode rows. In the phosphor screen forming process, phosphor particles are attached to the phosphor screen forming position of the exposed segment electrode to form a phosphor screen, and in the assembly process, a grid electrode is installed on the insulating layer. A dot array fluorescent tube formation method. 2. In the electrode forming step, the surface of the substrate is intermittently eroded along its longitudinal direction to form a row of recesses, a conductive material is adhered to each of these recesses to form a segment electrode, and an insulating layer is formed. In the formation step, after forming an insulating layer on the substrate surface including the segment electrodes, the segment electrodes at the phosphor screen forming position where the phosphor is to be attached are exposed in dots to form segment electrode rows, and the grid electrode formation step is performed. In this step, a conductive material is deposited on the insulating layer located between adjacent segment electrodes to form a grid electrode array, and in the phosphor screen forming step, phosphor is applied to the phosphor screen forming position of the exposed segment electrodes. A dot array fluorescent tube forming method characterized by forming a fluorescent screen by attaching particles. 3. In the electrode forming step, the surface of the substrate is intermittently eroded along its longitudinal direction to form a row of recesses, a conductive material is adhered to each of these recesses to form a segment electrode, and an insulating layer is formed. In the formation step, after forming an insulating layer on the substrate surface including the segment electrodes, the segment electrodes at the phosphor screen forming position where the phosphor is to be attached are exposed in dots to form segment electrode rows, and the grid electrode formation step is performed. In this step, a conductive material is deposited on the insulating layer located between adjacent segment electrodes to form a grid electrode array, and in the phosphor screen forming step, the substrate is immersed in a solvent in which phosphor particles are dispersed. A method for forming a dot array fluorescent tube, characterized in that a phosphor screen is formed by attaching phosphor particles to the phosphor screen forming position of the segment electrode by electrophoresis using the grid electrode as a counter electrode to the segment electrode. .