JPH0668949B2 - Phosphor screen forming method - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for forming a phosphor screen of a phosphor dot array tube used in a fluorescent display tube, an optical writing section of an optical printer, and the like, and is also applicable to a flat display panel and the like. .

[0002]

2. Description of the Related Art In a phosphor dot array tube, a phosphor screen is formed on a large number of strip electrodes (segment electrodes) arranged in one direction or in a plurality of lines in one direction, and the phosphor screen is enclosed in a vacuum container together with a hot cathode. Then, while generating thermoelectrons from the hot cathode, a positive voltage is selectively applied to the strip electrodes to attract the thermoelectrons to the selected strip electrodes, which are emitted when they collide with the phosphor screen. The display is performed by fluorescence and is applied to a fluorescent display tube, a bar code display tube, an optical writing section of an optical printer, a flat display panel, or the like.

4 and 5 are an exploded perspective view and a sectional view showing an example of a phosphor dot array tube, in which a substrate 20 is glass,
A series of strip-shaped electrodes 21 made of ceramic, resin, etc. are arranged in a row in the longitudinal direction of the substrate 20. Dot-shaped fluorescent screens 26 are individually formed on the strip electrodes 21 to form a dot array. The size of each phosphor screen 26 is 40 × 40 μm.
² is extremely fine, but in the example shown,
In order to make the shape of the phosphor screen easier to understand, the dimensions of the phosphor screen are shown larger than those of other members.

On both sides of the array of fluorescent screens 26 of the substrate 20,
Insulator layers 22a and 22b are formed along the longitudinal direction of the substrate, and grid electrodes 23a and 23b are formed thereon, respectively. Further, reference numeral 24 indicates a tungsten wire as a hot cathode extended in the longitudinal direction of the substrate, and the surface thereof is coated with an electron emissive substance such as BaSrO. Further, reference numeral 25 is a face member formed of a transparent material such as glass, and is integrated with the substrate side as shown in FIG. Thus, substrate 2
0, insulator layers 22a, 22b, grid electrodes 23a, 2
3b, the face member 25 forms a closed space, and in this space, the strip-shaped electrode 21, the fluorescent surface 26 of the fluorescent material layer,
The hot cathodes 24, 24 are enclosed and the closed space is highly evacuated.

Now, in the phosphor dot array tube having the above structure, when an appropriate voltage is applied to the grid electrodes 23a and 23b and an alternating voltage of several tens of mA is passed to the hot cathodes 24 and 24, the hot cathode 24 and 24 is heated by Joule heat and emits thermoelectrons. In this state, when a positive voltage is applied to one of the strip-shaped electrode rows 21 to set it to a positive potential, the thermoelectrons are attracted to the electrode portion of the strip-shaped electrode having a positive potential and collide with the electrode portion. The energy state of the fluorescent substance on the fluorescent screen 26 is excited. The excited fluorescent substance emits fluorescence when returning to the ground state, and this fluorescence is observed via the face member 25.

By the way, in the phosphor dot array tube having the above-mentioned structure, when the phosphor screen is formed on the strip-shaped electrodes, the size of the phosphor screen needs to be accurately controlled, and the luminance is not changed with time. It is necessary to form a phosphor screen with less deterioration. Therefore, JP-A-62-15453
Various phosphor screen forming methods have been proposed in the past, such as the invention described in JP-A-0.

In the phosphor screen forming method described in the above publication, at least one row of strip electrodes made of a conductive material is provided on the substrate in the electrode forming step, and the substrate surface including the strip electrodes is formed on the substrate surface in the insulating layer forming step. A segment electrode row is formed by forming an insulating layer that exposes a part of the strip electrode along the arrangement direction of the strip electrodes, and in the photoresist layer forming step, the insulating layer and the segment electrode row are formed by photoresist. After coating with a layer, only the segment electrode row-shaped photoresist layer is removed in a dot shape to expose the segment electrode row, and in the phosphor screen forming step, each exposed segment electrode is exposed to fluorescence. A dispersion liquid of body particles is dropped and attached to form a phosphor screen, and in the photoresist layer removing step, the photoresist layer is removed to form a phosphor dot array. It is.

Next, with reference to FIG. 6, a more specific example of the conventional phosphor screen forming method for phosphor dot array tubes will be described.

The method shown in FIG. 6 is generally called a lift-off method. After the substrate is covered with a photoresist, the portion to which the phosphor is attached is removed by development exposure and then the electrode exposed by a method such as electrodeposition. A phosphor is attached to the part, and finally, the remaining resist layer is removed by a method such as baking to form phosphor dots.

First, a strip electrode 2 is formed on a substrate 1,
On the surface of the substrate including the strip-shaped electrodes 2, an insulating layer 3 exposing a part of the strip-shaped electrodes 2 is formed along the arrangement direction of the strip-shaped electrodes 2 to form a segment electrode row, and then a photoresist layer 4 is formed. The substrate 1 is covered with (a), and then, the portion to which the phosphor is to be attached is developed through the hole 5 of the photomask 6 (b), the portion is removed (c), and then a method such as electrodeposition is used. Thus, the phosphor 7 is attached to the exposed electrode portion (d), and finally, the remaining photoresist layer 4 is removed by a method such as baking (e) to form the phosphor dot 7.

Here, the photoresist 4 is provided to prevent the fluorescent substance from adhering to other than the exposed portion of the segment electrode 2. However, as the photoresist,
A positive photoresist is used due to accuracy problems. This positive photoresist is usually hardened by irradiating it with ultraviolet rays or the like so as not to be dissolved in an organic solvent such as IPA used as a dispersion medium at the time of electrodeposition. Remove.

However, in this method, when the photoresist is removed, it is considered that the adhering phosphor has an effect such that the luminous efficiency and the luminous life of the phosphor itself are shortened due to the atmosphere or the like. Further, if the resist is not sufficiently hardened uniformly in the longitudinal direction of the substrate, the resist cannot be dissolved to form an appropriate phosphor dot during electrodeposition, or the electrodeposition solution may be contaminated, On the other hand, if it is partially over-hardened, the resist cannot be removed under normal baking conditions and remains on the substrate surface, adversely affecting various characteristics (luminance, life, etc.) after tube formation. It is also possible that it will cause a problem.

By the way, the insulating layer conventionally used for the fluorescent dot array tube is formed by a method such as screen printing so as to directly cover the strip electrode made of aluminum (A1) or the like. The layer is composed of lead borosilicate glass containing lead oxide as a main component, has high corrosiveness, and deteriorates A1 which is a strip electrode.
In addition, after being applied by screen printing, it will be
There is a problem that the A1 electrode is corroded during firing under the condition of 600 ° C. or due to adhesion of water in a high-humidity atmosphere, resulting in a significant decrease in electrical conductivity.

In order to solve the above-mentioned problems, the applicant of the present invention did not use the above-described method of forming a phosphor dot pattern by a photoresist, but rather the entire process.
We proposed a method for forming a phosphor screen that does not affect the phosphor itself and does not affect the properties after the bulb.

Further, in response to the above-mentioned problem of corrosion, since corrosion occurs at the interface between the aluminum thin film and the insulating layer,
Proposed to provide a film or layer free from impurities such as SiO ₂ between the aluminum wiring and the insulating layer to eliminate the cause of corrosion occurring at the interface and to improve the life of the phosphor dot array tube. did.

FIG. 7 is a view for explaining an example of the phosphor screen forming method previously proposed by the present applicant. In the electrode forming step, first, a conductive material 2 is formed by using a method such as sputtering or vacuum deposition. Are attached to the substrate surface 1. As the conductive material, A1 is used in terms of cost. Next, a strip-shaped wiring pattern 2 of A1 is formed by a normal photolithography method (a).

Next, in the insulating pattern layer forming step,
For example, a SiO ₂ film is used as the insulating film, and the low temperature (400 ° C.
And plasma CVD below), using the method according SiO ₂ film-forming coating liquid or the like, the SiO ₂ film 8 formed to cover on the strip-shaped A1 wiring pattern 2 (b). Incidentally, CV
When the D method is used, in the case where the underlying electrode 2 is a conductive material such as A1 which is weak against heat, there arises a problem that a large number of protrusions such as Healock caused by movement of grain boundaries occur at high temperature.
The film is formed at a low temperature.

In the case of using the coating liquid, for example, a SiO ₂ film forming coating liquid OCD (manufactured by Tokyo Ohka Co., Ltd.)
When applied with a spinner using the above, a SiO ₂ film having a film thickness of up to about 3000 Å can be obtained, and it has heat resistance up to about 1000 ° C.

After the strip-shaped electrode array 2 is covered with the SiO ₂ insulating layer film 8 by the above-mentioned insulating pattern layer forming step, first, similarly to the ordinary photolithography step, first by the photoresist layer forming step, SiO _{2 is} formed. The photoresist layer 4 is formed on the insulating film 8 (c), and the photomask 6 is formed.
Is used to perform exposure / development (d), and a resist pattern 4 is formed in which the photoresist layer on the dot portions to which the phosphor on the strip electrode array 2 should be attached is removed (e). Then, in the next etching step after forming the resist pattern 4, the portion of the SiO ₂ insulating film 8 to which the phosphor is attached is removed by etching (f).

Next, after the above etching process is completed, the excess resist is completely removed using a stripping solution or the like in the photoresist layer removing process.
The electrode 2 is exposed (g).

Next, a strip-shaped A1 is formed by an insulating layer forming process.
An insulating layer 3 is formed by a conventional method on the surface of the substrate 1 including the electrode array, in which a part of the electrode including an exposed portion to which the phosphor is to be attached is exposed along the arrangement direction of the electrodes (h).

After the insulating layer 3 is formed, in the phosphor screen forming step, a desired phosphor dot array is obtained by attaching the phosphors 7 to the exposed portions of the electrode rows 2 in a dot shape by an electrodeposition device. Can be done (i).

In the phosphor dot array tube in which the dot array-shaped phosphor screen 7 is formed in this manner, the SiO ₂ insulating film 8 is provided between the A1 wiring (A1 electrode) 2 and the insulating layer 3.
Since the A1 wiring (A1 electrode) 2 and the insulating layer 3 do not come into direct contact with each other, the occurrence of breakage of the A1 wiring due to corrosion, which has been a problem in the prior art, is remarkably improved. .

Further, in the above-mentioned phosphor screen forming method, since the phosphor screen is formed after the photoresist is removed, the phosphor 7 is not affected by the heat or the organic solvent when removing the photoresist, and the phosphor 7 Problems such as deterioration are resolved.

FIG. 8 is a view for explaining another example of the phosphor screen forming method previously proposed by the present applicant, in which the process order of the phosphor screen forming method shown in FIG. 7 is changed. The step of forming the insulating layer 3 is performed after the step of forming the insulating pattern layer 8 and immediately before the step of forming the photoresist layer 4.

That is, the step (a) of forming the electrode 2 and the step (b) of forming the insulating pattern layer 8 are the same as the steps shown in FIGS. 7A and 7B, and the formation of the insulating layer 8 is performed. Steps after the step ((b) of FIG. 8), that is, (c) to FIG.
The process of (h) is the same as the process of removing the insulating layer forming process ((g) of FIG. 7) from the processes of (c) to (i) of FIG.

By the way, the process shown in FIG. 7 or the process shown in FIG.
In the fluorescent tube in which the fluorescent substance dot array is formed through the process shown in FIG.
There is a case where a charge-up phenomenon occurs in which electrons from the cathode filament are stagnated on the surface of the insulating pattern layer 8 in this case, and the insulating pattern layer 8 is a boundary surface portion between the insulating layer 3 and the electrode surface of the A1 strip electrode 2. It is possible to adopt a configuration in which it is formed only on the substrate 1, or a pseudo electrode for preventing charge-up is additionally formed between the A1 strip electrodes 2.

According to the method for forming fluorescence previously proposed by the present applicant, instead of the photoresist, the fluorescent surface is formed by coating with an insulating layer film that remains after tube formation and patterning. However, in these, it is necessary to place a control electrode obtained by etching a metal plate (stainless steel is most often used) on the insulating layer after forming the phosphor screen, and fix it with a low melting point glass. The dimensional accuracy, the assembly position accuracy, and the like of the control electrode greatly affect the brightness of the phosphor. In particular, the assembly accuracy is very poor compared to other accuracy.
Further, since the strength of the control electrode itself is required, it is difficult to reduce the thickness to 50 μm or less, and there is less freedom in designing the height of the upper surface of the control electrode.

Therefore, the present applicant separately provided a metal thin film directly on the insulating film to be patterned without newly providing an insulating layer, and used this as a control electrode, whereby the accuracy of the manufacturing method was simplified. We have proposed a method for forming a phosphor screen that includes the step of forming a high control electrode.

FIG. 9 is a view for explaining an example of the phosphor screen forming method separately proposed by the applicant, and FIG. 9A shows an electrode forming process for forming the electrode 2 on the substrate 1. , Fig. 9
9A and 9B are insulating film forming steps for forming the insulating film 10, FIG. 9C is a metal thin film covering step for forming the metal thin film 11, and FIG. 9D is a resist applying step for applying the resist 12. 9 (e) and FIG. 9 (e) are resist patterning steps (I) and 9 (f) for forming the resist pattern 12a.
9 (g) is a resist removing step of removing the resist 12, FIG. 9 (h) is a resist applying step (II) of applying the resist 13, and FIG. 9 (i). Is the resist pattern 13a
9 (j) is an insulating film etching step of etching the insulating film 10, FIG.
9K is a resist removing step of removing the resist 13, and FIG. 9L is a fluorescent screen forming step of forming the fluorescent screen 7.

However, in this case, the insulating film 10 (SiO ₂ or the like) having a thickness of about 3 μm is apt to be cracked due to the difference in thermal expansion coefficient between the soda glass of the substrate 1 and A1 in the thermal process at the time of tube formation. Generally, if the thickness is 1 micron or less, cracks are less likely to occur, but an uncovered portion is likely to occur at a step of the strip-shaped electrode 2 of A1 of about 1.2 microns. When a crack occurs, a control electrode is formed on the insulating film 10 by a metal thin film, so that the crack does not allow conduction to the metal thin film portion in the vicinity of the phosphor 7, making it difficult for electrons to collide with the phosphor. May not emit light.

On the other hand, when the insulating layer 14 is formed by thick film printing as shown in FIG. 10, if a glass having a low melting point is used, for example, cracks do not occur, but 10
Since the thickness is generally more than a micron, the insulating layer 14 on the lower surface of the metal thin film 11 is side-etched by about 7 to 10 microns by wet isotropic etching (14a in FIG. 10E). A1 of this part (11a,
11b) is easily broken or short-circuited with the strip electrode 2 on the substrate (FIG. 10 (f)). Especially at the end,
Such defects are likely to occur in the process of forming a fluorescent screen on the electrode surface of the substrate by electrodeposition. Further, since the strip-shaped electrode is located at the back of the control electrode, it is very difficult to attach the phosphor particles to the control electrode to form a uniform and minute phosphor screen.

[0033]

[Object] The present invention has been made in view of the above circumstances, and improves an insulating layer as a base of a control electrode using a metal thin film to newly add another insulating layer in addition to an insulating layer for patterning. By providing, the manufacturing method is simple and highly accurate,
Moreover, it is an object of the present invention to provide a highly reliable phosphor screen forming method including a step of forming a control electrode.

[0034]

The present invention has a first object to achieve the above object.
In the method for forming a phosphor screen in a phosphor dot array tube, an electrode forming step of providing at least one row of strip electrodes made of a conductive material on a substrate, and a thin film having an insulating property on the substrate surface including the strip electrodes. First insulating layer forming step of covering, and second insulating layer forming step of covering the surface of the substrate covered with the first insulating layer with a thin film thicker than the first insulating layer with an insulating substance having openings And a step of coating the surface of the substrate coated with the two insulating films with a metal thin film, a step of partially removing the metal thin film in the opening of the second insulating layer, and One of the electrode portions to which the phosphor is to be attached, the step of removing at least the portion of the exposed first insulating layer covering the portion to which the phosphor is attached to expose the strip electrode partially. Attach phosphor to one It is obtained by comprising a phosphor screen forming step for forming a fluorescent screen by.

Secondly, in the method for forming a phosphor screen in a phosphor dot array tube, an electrode forming step of providing at least one strip electrode made of a conductive material on the substrate in a row, and opening the substrate surface including the strip electrodes. A first insulating layer forming step of coating a portion with an insulating substance, and coating the surface of the substrate covered with the first insulating layer with a thin film thinner than the first insulating layer made of an insulating substance A second insulating layer forming step, a step of covering the substrate surface with a metal thin film covered with the two insulating films, and a step of partially removing the metal thin film in the opening of the first insulating layer. And a step of removing at least the portion of the second insulating layer exposed by removing the metal thin film to cover the portion to which the phosphor adheres and partially exposing the strip electrode, and the phosphor should adhere. Electrode part It is obtained is characterized in that one by one by attaching a phosphor and a phosphor screen forming step for forming a fluorescent screen.

Thirdly, in the phosphor screen forming method in the phosphor dot array tube according to the first and second embodiments, the substrate is used as an etchant for removing the insulating layer for patterning the strip electrodes by etching. It is characterized in that it is pre-coated with an insulating material having an etching rate substantially the same as or lower than that of this insulating layer. Hereinafter, description will be given based on examples of the present invention.

FIG. 1 is a diagram for explaining an embodiment (corresponding to claim 1) of the phosphor screen forming method according to the present invention. First, in the electrode forming step, a conductive material such as A1 is sputtered or the like. It is formed on the soda glass substrate 1 by the method, and the strip-shaped A1 is formed by a normal photolithography process.
The wiring pattern 2 is formed (a).

Next, in the first insulating layer forming step, a 1-micron-thick first insulating layer 15 is formed on the spinner or the like as described above using, for example, a SiO film as an insulating film (b).

After coating with the insulating film 15, as a second insulating layer forming step, low melting point glass is printed and baked by a thick film printing technique using, for example, a screen printing method to obtain a thickness of 10
An insulating film 16 (16a, 16b) having a thickness of 20 μm is formed (c).

This insulating film waits at least in the range including the fluorescent screen and the fluorescent screen side end of the control electrode as an opening. Further, a conductive material such as A1 is formed again as a metal thin film 17 on the substrate by a method such as sputtering (d), and a range including at least a portion forming a fluorescent screen is removed by a normal photolithography process or the like. The control electrode patterns 17a and 17b are formed (e).

This is a resist coating process. For example, if a positive type resist 5 (OFPR800, Tokyo Ohka Co., Ltd.) is applied by a spinner, it can be easily made to have a thickness of about 1.2 microns, and ultraviolet rays can be applied to the resist removing portion. After the exposure, the resist is patterned by immersing it in an alkaline developer (NMD-W, Tokyo Oka, etc.), and then etching the metal thin film with an acidic etchant (for example, phosphoric acid as a main component). If necessary, the resist is removed.

Then, after that, the first insulating layer 15 in the portion to which the phosphor adheres is removed (f), and the strip electrodes 2 are exposed, and at the same time, the insulating layers 15a, 1a are arranged in the direction perpendicular to the array direction.
Patterning is performed with 5b. This is also the case that the resist on the insulating film covering the part to which the fluorescent substance adheres is removed by applying the resist again on this substrate by the ordinary photolithography method, exposing and developing, and then insulating this part. Etch away the film.

Next, in the resist removing step, the excess resist is completely removed with a stripping solution or the like, so that the A1 electrode and the control electrode at the portion where the phosphor adheres are exposed. Finally, the A1 electrode in the portion to which the phosphor is attached is subjected to electrodeposition in an electrodeposition liquid containing phosphor particles to form a phosphor screen 7 (g).

This is because the control electrode is formed of a metal thin film formed on a thin SiO ₂ film formed by using a spinner or the like, so that the control electrode near the fluorescent screen has high accuracy and the height of the electrode surface is high. The height can be lowered and it approaches the fluorescent screen. Also,
Since this control electrode has only a comparatively small portion on this SiO ₂ film and most of the underlying layer is an insulating layer made of low melting point glass, cracks are less likely to occur due to a thermal process at the time of tube formation, and the production is easy. become.

Further, since the conventional insulating layer made of lead borosilicate glass containing lead oxide as a main component is not in direct contact with soda glass or A1 strip electrodes, corrosion of metal wiring such as A1 is unlikely to occur. . Furthermore, since the surface to which the phosphor is attached is not covered with a resist, the electrode surface is unlikely to be contaminated and the phosphor is easily attached. Further, since there is no resist removing step after the phosphor is attached, the efficiency of the phosphor is unlikely to decrease.

FIG. 2 is a view for explaining another embodiment (corresponding to claim 2) of the present invention. First, in the electrode forming step, a conductive material such as A1 is soda-glass by a method such as sputtering. A strip-shaped A1 wiring pattern 2 is formed on a substrate 1 by a normal photolithography process (a).

Next, in the first insulating layer forming step, low melting point glass is printed and baked by a thick film printing technique using, for example, a screen printing method, and the insulating film 16 (16a, 16b) having a thickness of 10 to 20 microns is formed. ) Is formed (b).

The insulating film waits at least in the range including the fluorescent screen and the fluorescent screen side end of the control electrode as an opening. After coating with the insulating film 16, in the second insulating layer forming step, for example, a SiO ₂ film is used as the insulating film, and the second insulating layer 15 having a thickness of 1 μm such as a spinner is formed as described above ( c).

After this, the same procedure as in the embodiment shown in FIG. 1 is carried out. Again, a conductive material such as A1 is again formed as a metal thin film 17 on the substrate by a method such as sputtering (d), and a normal photolithography process is performed. The control electrode patterns 17a and 17b are formed by removing a range including at least a portion that forms a fluorescent screen by, for example, (e).

After that, the second insulating layer 15 at the portion where the phosphor adheres is removed (f), the strip electrodes are exposed, and at the same time, the array direction is patterned by the insulating layers 15a and 15b in the vertical direction. After that, the A1 electrode in the portion to which the phosphor adheres is subjected to electrodeposition in an electrodeposition solution containing phosphor particles to form a phosphor screen 7 (g).

This embodiment is basically the same as that of the first embodiment, but the structure is slightly different because the order of formation is changed. This is because the precision of the control electrode near the phosphor screen is high, the height of the electrode surface can be reduced, and it can approach the phosphor screen.
In the same way, the control electrode is less likely to be cracked due to the heat step of tube formation, and the production is easy.

However, as compared with the case of the embodiment shown in FIG. 1, since the conventional insulating layer made of lead borosilicate glass containing lead oxide as the main component is in direct contact with soda glass or A1 electrode. Corrosion of metal wiring such as A1 is likely to occur. However, although it depends on the thickness and the material, the SiO ₂ film is formed after the thermal process of forming the low melting point glass, for example, at a temperature of 500 ° C. or higher for about 60 minutes, so that cracks in the SiO ₂ film may occur. There is also an advantage that it is less likely to occur than in the case of.

FIG. 3 is a diagram for explaining another embodiment of the present invention (corresponding to claim 3). This embodiment is a substrate 1
1 is provided with a SiO ₂ coat 18 previously coated thereon. Therefore, this coating film has the same etching rate as that of the insulating layer with respect to the hydrofluoric acid-based etchant that etches away the insulating layer for patterning the strip electrode.
The etching rate for the strip-shaped electrode made of A1 is low.

When the etching from (e) to (f) in FIGS. 1 and 2 is performed after applying such a coating, only the strip-shaped electrode A1 has a smaller etching rate.
It is possible to remove only the necessary portion of the insulating layer while maintaining the shape of the A1 electrode on the substrate.

Further, since the strip electrodes made of soda glass A1 are not in direct contact with each other, the electrodes are very resistant to corrosion.

【effect】

As is apparent from the above description, claim 1
According to the invention of 2 and 2, in the method for forming the phosphor screen of the phosphor dot array, the strip-shaped electrode is covered with two layers of insulating films, and the strip-shaped electrode is patterned with the thin insulating film, Since the thin metal film control electrode is formed by conducting the thin metal film formed on the film, the control electrode has high accuracy, the height of the electrode surface is low, and the phosphor dot is easy to manufacture. An array can be provided.

According to the third aspect of the present invention, in the method for forming a phosphor screen of a phosphor dot array tube, the insulating layer is removed from the substrate by an etchant for etching away the insulating layer for patterning the strip electrodes. Since it is pre-coated with an insulating material having an etching rate almost the same as or smaller than that, it is possible to remove only the insulating layer on the electrode surface to which the phosphor is attached without affecting the others.

[Brief description of drawings]

FIG. 1 is a process chart for explaining an embodiment of a phosphor screen forming method according to the present invention.

FIG. 2 is a process drawing for explaining another embodiment of the present invention.

FIG. 3 is a cross-sectional configuration diagram of a main part process for explaining another embodiment of the present invention.

FIG. 4 is an exploded perspective view showing an example of a phosphor dot array tube.

5 is a cross-sectional view of FIG.

FIG. 6 is a process drawing showing a cross-sectional view of a specific example of a phosphor screen forming method according to a conventional technique.

FIG. 7 is a process diagram showing a cross-sectional view of another specific example of the phosphor screen forming method according to the conventional technique previously proposed by the applicant.

FIG. 8 is a process diagram showing in cross section another specific example of the phosphor screen forming method according to the conventional technique previously proposed by the applicant.

FIG. 9 is a process diagram showing a cross-sectional view of a specific example of a phosphor screen forming method according to the prior art separately proposed by the applicant.

FIG. 10 is a sectional process diagram for explaining an example of a case where the insulating film 3 shown in FIG. 9 is formed by film thickness printing.

[Explanation of symbols]

1 substrate 2 wiring pattern 3,8,10,14,15 (15a, 15b), 16
(16a, 16b), 18 Insulating layer 4, 12, 13 Photoresist layer 6 Photomask 7 Phosphor 11 (11a, 11b), 17 (17a, 17b) Metal thin film (control electrode)

Claims (3)

[Claims] 1. A method for forming a phosphor screen in a phosphor dot array tube, comprising: an electrode forming step of providing at least one row of strip electrodes made of a conductive material on a substrate; and insulating the substrate surface including the strip electrodes with insulation. A first insulating layer forming step of covering with a thin film having, and a second insulating covering the surface of the substrate covered with the first insulating layer with a thin film thicker than the first insulating layer with an insulating substance having openings A layer forming step, a step of coating the substrate surface covered with these two insulating films with a metal thin film, and a step of removing a part of the metal thin film in the opening of the second insulating layer. And a step of removing at least a part of the first insulating layer exposed by removing a part of the metal thin film to expose a part of the strip-shaped electrode, and each of the exposed electrode parts. Shape phosphor screen by attaching phosphor A phosphor screen forming method, which comprises a phosphor screen forming step for. 2. A method of forming a phosphor screen in a phosphor dot array tube, comprising: an electrode forming step of providing at least one row of strip electrodes made of a conductive material on a substrate; and forming an opening at the substrate surface including the strip electrodes. A first insulating layer forming step of covering with a provided insulating material, and a step of covering the substrate surface covered with the first insulating layer with a thin film thinner than the first insulating layer made of an insulating material. A second insulating layer forming step, a step of coating the substrate surface covered with these two insulating films with a metal thin film, and removing a part of the metal thin film in the opening of the first insulating layer And a step of removing at least a part of the second insulating layer exposed by removing a part of the metal thin film to expose a part of the strip-shaped electrode, and one of the exposed electrode parts. Attach the phosphor to one A phosphor screen forming method, which comprises a phosphor screen forming step for forming a fluorescent screen. 3. The phosphor screen forming method for a phosphor dot array tube according to claim 1 or 2, wherein the substrate is insulated against an etchant for etching away an insulating layer for patterning the strip electrodes. A method of forming a glorious surface, characterized in that the layer is previously coated with an insulating material having an etching rate substantially equal to or lower than that of the layer.