JPH0417246A - Fluorescent dot array tube and fluorescent screen forming method - Google Patents

Abstract

PURPOSE:To obtain the sufficient light emitting luminance and reliability by forming an Al anode electrode and wiring into the structure which is not corroded by an insulating layer and outside moisture. CONSTITUTION:An anode electrode 2 of Al wiring pattern is formed by an usual photolithography process, and thereafter, photoresist 4 is coated, and paternning is performed with masks 5, 6 so that the resist 4 is left at only part where a fluorescent member 7 is adhered. Next, electric field oxidation is performed to the exposed Al electrode and wiring as an anode in the electrolytic solution for generating an insulative film 13. Thereafter, the surplus resist 4 is eliminated to expose the Al electrode 2, and after forming an insulating layer 3, the fluorescent member 7 is adhered to the exposed Al electrode part by an electrodepositioning device. The fluorescent member itself is not thereby influenced by the resist over the whole process, and a fluorescent dot array tube, of which surface made of Al thin film is oxided to some degree so that corrosion is not generated, can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a phosphor dot array tube and a phosphor screen forming method. applicable.

L rice string! Publicly known documents describing the prior art related to the present invention include, for example, Japanese Patent Laid-Open No. 61-267224. This Japanese Patent Application Laid-Open No. 61-267224 relates to a lift-off method, which includes an electrode forming process in which at least one row of strip-shaped electrodes made of a conductive material is provided on a substrate, and a method for avoiding contact between the grid electrode and the strip-shaped electrodes. an insulating layer forming step of forming a segment electrode array by forming an insulating layer exposing a part of the strip electrodes along the arrangement direction of the strip electrodes on the surface of the substrate including the strip electrodes; A resist that covers the insulating layer and the segment electrode array with a photoresist layer, and then removes the photoresist layer in the form of a slit with a desired width along the arrangement direction of the segment electrode array to expose the segment electrode array. A layer forming step, a phosphor screen forming step of attaching phosphor particles to each of the exposed segment electrodes to form a phosphor screen, and a photoresist layer removing step of removing the photoresist layer. A method for forming a phosphor screen is disclosed.

Furthermore, Japanese Patent Application Laid-Open No. 64-2672224 relates to an electrodeposition method, and discloses a method of electrodepositing phosphor particles onto a large number of segment electrodes arranged in an array on an electrodeposition substrate. That is, in this method of forming a phosphor screen, first, a strip-shaped anode electrode and an insulating layer are formed, and then a dot pattern to which the phosphor is attached is formed using a photoresist, and then the phosphor is attached, and then a photoresist layer is formed. In this method, a phosphor screen is formed by removing the phosphor.

Figures 3(a) and 3(b) are diagrams of the conventional structure of a phosphor dot array tube, with figure (,) being an overall perspective view, and figure (b) being figure (,
) is a sectional view taken along the line ■-■. In the figure, 21 is a glass substrate;
22 is an aluminum anode electrode, 23 is a phosphor (light emitter) segment, 24a, 24b are insulator layers, 25a, 25b are control (grid) electrodes, 26 is a cathode electrode, 27 is a high vacuum chamber (10-7 torr or less) , 28 is a face glass. A series of phosphor segments 23 are provided on the glass substrate 21.
are arranged in a row in the longitudinal direction of the glass substrate 21, and each of the phosphor segments 23 has a phosphor screen and an aluminum anode electrode 22 formed thereon. Insulator layers 24a and 24b are formed along the longitudinal direction of the glass substrate 21 on both sides of the phosphor screen arrangement of the glass substrate 21.
4a and 24b.

Control electrodes 25a and 25b are formed, respectively. A cathode electrode 26 is stretched in the longitudinal direction of the glass substrate 21,
Electron radioactive material is coated on the surface. In addition, a face glass 28 formed of a transparent material such as glass
is integrated with the glass substrate side. In this way, the glass substrate 21, the insulator layers 24a, 24b, and the control electrodes 25a, 2
5b and the face glass 28 form a closed space, within which the phosphor segment 23 and the cathode electrode 26 are confined. The closed space is highly evacuated.

When an appropriate voltage is applied to the control electrodes 25a and 25b and an alternating current is passed through the cathode electrode 26, the cathode electrode 26
is heated by Joule heat and emits thermoelectrons.

In this state, when a positive voltage is applied to one of the phosphor segments 23 to make it a positive potential, the thermoelectrons are attracted to the electrode portion of the phosphor segment 23 at a positive potential,
When absorbed into the electrode part, the energy state of the fluorescent substance on the fluorescent screen is excited. The excited fluorescent substance emits fluorescence when returning to the ground state. This fluorescence is on the face glass 2.
observed through 8.

FIG. 4 is a diagram showing a conventional method for forming a phosphor screen of a phosphor dot array tube. 54 is an insulating layer, 54 is a resist layer, 55 and 56 are masks, and 57 is a phosphor dot. First, in an electrode forming step, an anode electrode 52 is formed on a substrate 51, and an insulating layer 53 is formed in the next insulating layer forming step. In the next photoresist layer forming step, first, in step (a), the substrate 51 is coated with photoresist to form a resist layer 54, and then in steps (b) and (c), the portion to which the phosphor is attached is is removed by development exposure using masks 55 and 56. (d
) In the phosphor screen forming process, a phosphor is attached to the exposed electrode part by a method such as electrodeposition, and in the photoresist layer removal process, the last remaining resist layer is removed by a method such as baking to form a phosphor. This forms dots 57.

FIGS. 5(a) and 5(b) are diagrams showing an example of a method for actually depositing a phosphor, which is generally called electrophoresis (electrodeposition). In the figure, 60 is a stirring blade, 61 is a substrate, 62
is an anode electrode, and 63 is an insulating layer.

64 is a resist layer, 65 is a mask, 66 is a power source, 67 is a motor, and 68 is a dispersion medium (phosphor, IPA; isopropyl alcohol, etc.), which stirs the dispersion medium containing the phosphor (IPA is used as the solvent). The phosphor is attached to the desired location by stirring with a blade and applying an electric field between the counter electrode and the segment electrode. Positive-type photoresists are used due to precision issues (for example, 0FPR800 manufactured by Tokyo Ohka Co., Ltd.).Positive-type photoresists are usually dissolved in organic solvents such as IPA used as dispersion media during electrodeposition, so it is difficult to dissolve them. After hardening the resist layer by irradiating it with ultraviolet rays and attaching the phosphor to prevent the resist from burning, the resist layer is removed by baking or the like.

When this resist is removed, the attached phosphor is affected by the atmosphere, such as reducing the luminous efficiency and luminous life of the phosphor itself. Additionally, if the resist is not hardened uniformly and sufficiently over the long and horizontal directions of the substrate, the resist may dissolve during electrodeposition, making it impossible to form appropriate phosphor dots, contaminating the electrodeposition solution, or On the other hand, if excessive hardening is done in some areas, the resist cannot be removed under normal firing conditions and remains on the substrate, which may adversely affect characteristics such as brightness and lifespan after tube formation. .

In addition, from the viewpoint of reliability, the insulating layer conventionally used in fluorescent display tubes is formed by a method such as screen printing so as to directly cover the strip-shaped electrodes such as Al, but this insulating layer is made of lead oxide. Since it is composed of lead borosilicate glass as the main component, it is highly corrosive and deteriorates the Al that is the strip electrode. After being applied by screen printing, it is fired in the atmosphere at 550 to 600 degrees Celsius. The At electrode is corroded due to water adhesion due to the high humidity atmosphere.
Corrosion occurs at the interface between the Al thin film and the insulating layer,
A problem arises in that electrical conductivity is significantly reduced.

Purpose The present invention was made in view of the above-mentioned circumstances.
Rather than using a resist-based phosphor dot pattern, the phosphor itself should not be affected throughout the entire process, and the properties after tube formation should also not be affected at all.
It is an object of the present invention to provide a phosphor dot array tube and a method for forming a phosphor screen, which are configured to prevent corrosion from occurring at the interface with the insulating layer by oxidizing the surface of a corrosion-prone Al thin film to some extent to form an insulating film. This was done as a.

In order to achieve the above object, the present invention provides (1) a substrate on which a rectangular anode electrode is formed of a conductive material, a phosphor attached to the surface of the anode electrode, and a phosphor arranged in an array. a plurality of light emitting segments arranged in a dot pattern; a grid electrode provided on the anode electrode via an insulating layer; and a cathode electrode provided on the phosphor within a face glass covering the grid electrode. The phosphor dot array tube is configured such that thermionic electrons generated from the cathode electrode are accelerated and controlled by the grid electrode, and the thermionic electrons are made to impinge on the phosphor to cause the phosphor to emit light. (2) an electrode forming step in which at least one row of strip-shaped anode electrodes made of a conductive material is provided on the substrate; , after coating the surface of the substrate including the strip-shaped anode electrode with a photoresist layer, the photoresist layer on the electrode portion where the phosphor does not adhere on the strip-shaped anode electrode array is removed, and the phosphor is attached. a photoresist layer forming step of covering the electrode portion with a photoresist layer; an anodic oxide film forming step of forming an anodic oxide film on the surface of the electrode portion not covered with the photoresist layer; and an electrode to which the phosphor is attached. a photoresist layer removal step of removing a portion of the photoresist layer, and a part of the strip-shaped anode electrode is removed on the substrate surface including the strip-shaped anode electrode along the arrangement direction of the strip-shaped anode electrode. an insulating layer forming step in which an exposed insulating layer is formed to form a segment electrode array; and a phosphor is applied to each electrode portion of the segment electrode array on which the anodized film is not formed, to which the phosphor is attached. The method is characterized in that a phosphor dot array is formed by a phosphor screen forming step in which a phosphor dot is deposited to form a phosphor screen. An explanation will be given below based on one embodiment of the present invention.

1 and 2 are process diagrams for explaining one embodiment of the method for forming a phosphor screen of a phosphor dot array tube according to the present invention. In the figures, 1 is a substrate, 2 is a strip of aluminum (Al) Anode electrode, 3 is an insulating layer, 4 is a photoresist, 5 is a transparent part of the mask, 6 is a blocking part of the mask, 7 is a fluorescent dot, 13
is an anodized film.

Hereinafter, the steps for forming the phosphor screen will be explained in order.

Step in Figure (a): In the electrode forming step, first a conductive material such as AI is formed on the substrate 1 by a method such as sputtering, and an anode electrode 2 having a rectangular Al wiring pattern is formed by a normal photolithography step. Form.

Steps in Figures (b) to (d); Next, the photoresist is
The resist is applied onto a substrate on which a wiring pattern has been formed using a method such as a spinner, and the resist is patterned using a mask 5.6 which leaves the resist 4 only in the areas to which the phosphor is to be attached.

Step in Figure (e): The photoresist may be of positive type or negative type. After applying post-baking to improve the chemical resistance of the resist film, the exposed A1 electrode and wiring are used as anodes to form an insulating film 13. is subjected to electric field oxidation in an electrolyte solution that produces As an electrolyte, it is better to use an electrolyte that does not cause the film to thicken because the voltage increases rapidly and significantly immediately after electric field oxidation, and the film does not thicken.Although it is okay to use an electrolyte that thickens the film, it is difficult to manage the time. Examples of substances that do not thicken the film include boric acid, ammonium borate, ammonium oxalate,
There are special mixed acids (boric acid i00gt borax 1g, diluted to 1 liter with pure distilled water), etc., and when used as an ammonium oxalate electrolyte for pure AI, it is about 13.
0 person/V, anode film thickness 200% under conditions of current efficiency 80%
Can create 0 to 4000 people. The membrane produced under these conditions has a specific gravity of approximately 3.2 g/cm'' (primary chemical formation), and is subjected to secondary chemical formation using a neutral solution and washed with pure water.

Step (f): After the anodic oxide film is formed, excess resist is removed to expose the Al electrode where the phosphor will be attached.

Step (g): Next, the insulating layer 3, which has been conventionally used, is formed by screen printing.

Step shown in FIG. 5(h): After that, a desired phosphor dot array can be obtained by depositing phosphor on the exposed Al electrode portion using an electrodeposition apparatus as shown in FIG.

The phosphor dot array produced in this way is not contaminated by resist during the tube-making process, and since the Al electrodes and wiring are not in direct contact with the insulating layer, there is no possibility of disconnection of the Al electrodes or wiring due to conventional corrosion. Development is significantly improved.

FIG. 2 is a diagram showing the flow of the phosphor screen forming process shown in FIG. The phosphor screen according to the present invention is formed through the steps of forming process → phosphor screen forming process.

Summer - As is clear from the above explanation, the present invention has the following effects.

(1) Effect 5 corresponding to claim 1 Since the structure of the phosphor dot array tube is such that the AI anode electrode and wiring are not corroded by the insulating layer or external moisture, the luminance of the phosphor after tube formation is reduced. Variations are reduced, local brightness reduction due to the A1 anode electrode and wiring over time is suppressed, and it can be used for optical writing in printers and the like. (2) Effects corresponding to claim 2;
In the phosphor screen formation method of the phosphor dot array tube, the phosphor dots are prevented from being adversely affected by the resist atmosphere, so sufficient luminous brightness can be obtained without reducing the luminous efficiency of the phosphor, and the phosphor screen Reliability in formation can be improved.

[Brief explanation of the drawing]

FIG. 1 is a process diagram for explaining an embodiment of the method for forming a phosphor screen of a phosphor dot array tube according to the present invention, FIG. 2 is a diagram showing the flow of the phosphor screen forming process, and FIG. FIG. 4 is a diagram showing a conventional example of a method for forming a phosphor screen of a phosphor dot array tube;
FIG. 5 is a diagram showing an example of a method for attaching phosphor. DESCRIPTION OF SYMBOLS 1... Substrate, 2... Strip-shaped aluminum (A1) anode electrode, 3... Insulating layer, 4... Photoresist, 5...
- Transmissive part of the mask, 6... Blocking part of the mask, 7...
Phosphor dots. 13...Anodic oxide film. Figure (b)

Claims (1)

[Claims] 1. A substrate on which a rectangular anode electrode is formed of a conductive material;
a plurality of light-emitting segments in a dot pattern arranged in an array by attaching a phosphor to the surface of the anode electrode;
It consists of a grid electrode provided on the anode electrode via an insulating layer, and a cathode electrode provided on the phosphor within the face glass covering the grid electrode, and the thermoelectrons generated from the cathode electrode are In a phosphor dot array tube configured to perform acceleration control using a grid electrode to cause thermionic electrons to strike the phosphor and cause the phosphor to emit light, the surface of the anode electrode other than the portion to which the phosphor is attached. A phosphor dot array tube characterized by having an insulating film formed by oxidizing the phosphor. 2. An electrode forming step of providing at least one row of strip-shaped anode electrodes made of a conductive material on a substrate; and after coating the substrate surface including the strip-shaped anode electrodes with a photoresist layer, forming the strip-shaped anode electrodes on the substrate; A photoresist layer forming step of removing the photoresist layer of the electrode part on the column to which the phosphor does not adhere and covering the electrode part to which the phosphor adheres with a photoresist layer, and the electrode part not covered with the photoresist layer. an anodic oxide film forming step of forming an anodic oxide film on the surface of the substrate, a photoresist layer removing step of removing the photoresist layer of the electrode portion to which the phosphor is attached, and a step of removing the photoresist layer on the surface of the substrate including the strip-shaped anode electrode. , an insulating layer forming step of forming a segment electrode array by forming an insulating layer that exposes a part of the strip-shaped anode electrodes along the arrangement direction of the strip-shaped anode electrodes, and forming an anodic oxide film. A phosphor dot array is formed by a phosphor screen forming step of forming a phosphor screen by attaching phosphor to each electrode portion of the segment electrode array to which phosphor is attached. Characteristic fluorescent screen formation method.