KR100471964B1 - A process for preparing a reinforced shadow mask - Google Patents

Abstract

Applying a voltage to the shadow mask for the color CRT used as a cathode and the vacuum vessel used as the anode, in which a gas such as BCl ₃ , boron, hydrocarbon and plasma generating gas are charged, nitrogen and boron are applied to the shadow mask by glow discharge. The shadow mask manufactured by bonding carbon atoms has an improved modulus of elasticity, which is hardly influenced by external vibration, shock, or vibration caused by speaker sound waves. The manufacturing method of the shadow mask is more effective than the conventional gas nitriding enhanced treatment method. Low temperature, short processing time and environmentally friendly.

Description

A PROCESS FOR PREPARING A REINFORCED SHADOW MASK}

[Industrial use]

The present invention relates to a method of reinforcing a shadow mask, and more particularly, a method of reinforcing a shadow mask, which can reduce the influence of external impact or vibration by increasing the elastic modulus and strength of the shadow mask using a plasma generator. It is about.

[Private Technology]

Shadow masks, used in color TVs and color monitors, perform color screening to select the electron beam irradiated from the electron beam, and use the Invar or A / K (aluminum-killed) steel mainly made of pure iron. It is common to manufacture hundreds of thousands of holes on the surface by a method of corrosion using photolithography.

The general manufacturing process of such a shadow mask is described in more detail as follows.

Roller leveling of the A / K steel gives plastic deformation to the mask plate to impart flatness and work hardenability and to form holes for passing electron beams. The process of forming a hole in the mask plate is performed by applying photolithography. The process is performed by applying a photoresist to the mask plate, exposing and developing, and etching. When the etching process is completed, a hole for passing a predetermined electron beam is formed in the shadow mask. As such, the shadow mask in which the holes are formed is subjected to an annealing process of heat treatment in a high-temperature hydrogen atmosphere to impart ductility, and then formed into a uniform form by pressing. After the foaming is completed, the mask plate is subjected to a degreasing process to remove foreign substances such as contamination and fingerprints, and then a blackening process is applied as a means to prevent the shadowing of the shadow mask.

The shadow mask manufactured as described above is mounted on a color cathode ray tube to serve as a bridge for matching electron beams from three electron guns to R, G, and B phosphor dots, respectively.

In FIG. 1, the shadow mask changes the path of the electron beam due to external impact. When the shadow masks 6 and 7 are shaken in this way, the positions of the holes 8 and 9 inside the mask are changed and the electron gun 11 is changed. The path of the electron beam 10 emitted from the () is also changed. As a result, the initial electron beam light emitting position P1 is moved to the light emitting position P2 after the vibration to emit unwanted phosphors, and thus there is a problem that the quality is deteriorated, such as screen shake or color purity deterioration.

In order to solve this problem, Japanese Patent Laid-Open No. 62-223950 attempts to improve the strength by forming a plating layer on the surface of the shadow mask, but this has the disadvantage of reducing the hole size of the shadow mask. In addition, Japanese Patent Laid-Open Publication Nos. 56-121257 and 1-276542 disclose methods for improving the strength of shadow masks through gas nitriding. However, this method has a high processing temperature, a long process time, and easy adjustment of the thickness of the reinforcing film. There is a problem such as environmental pollution by decomposition gas.

The present invention has been made to solve the problems of the prior art as described above, the present invention is to strengthen the shadow mask, improve the elastic modulus to reduce the effects due to external vibration, shock, vibration by speaker sound waves, etc. It is an object of the present invention to provide a method of strengthening a shadow mask using a plasma generating apparatus which is environmentally friendly and has a lower processing temperature and a shorter processing time than conventional gas nitriding strengthening treatment methods.

In order to achieve the object of the present invention as described above, the present invention provides a shadow mask for a color CRT, which is used as a cathode, and a vacuum discharge applied by applying a voltage to a vacuum container used as an anode, in which nitrogen gas and a plasma generating gas are charged. Provided are a method for strengthening a shadow mask in which nitrogen atoms are bonded to the shadow mask. Here, the voltage is 400 to 800V, the shadow mask is a plurality of holes for passing the electron beam is generated, it is preferable to use that the forming process for the curvature is completed, such a method is 400 to It is preferred to proceed at a temperature of 600 ° C.

In addition, the present invention applies a voltage to a shadow mask for a color CRT tube used as a cathode, and a vacuum vessel used as an anode, in which a BCl ₃ gas and a plasma generating gas are charged, thereby bonding boron atoms to the shadow mask by glow discharge. Provides a method of strengthening shadow masks. Here, the voltage is 400 to 800V, the shadow mask is a plurality of holes for passing the electron beam is generated, it is preferable to use that the forming process for the curvature is completed, such a method is 400 to It is carried out at a temperature of 600 ℃, the plasma generating gas is preferably hydrogen (H ₂ ) or argon (Ar).

In addition, the present invention is applied to a shadow mask for a color CRT tube used as a cathode, and a vacuum vessel used as an anode, in which a hydrocarbon gas and a plasma generating gas is charged to couple a carbon atom to the shadow mask by glow discharge. It provides a method of strengthening the shadow mask. Here, the voltage is 400 to 600V, the shadow mask is a plurality of holes for passing the electron beam is generated, it is preferable to use that the forming process for the curvature is completed, this method is 800 to It is preferable to proceed at a temperature of 1000 ℃ and a pressure of 0.1 to 10 torr, the plasma generating gas is preferably hydrogen or argon, the hydrocarbon gas is methane (CH ₄ ), propane (C ₃ H ₈ ) And it is preferable to select from the group which consists of these mixed gases.

EXAMPLE

Representative Example

1) Reinforcement of shadow mask by nitrogen

A voltage of 400 to 800 V is applied using a shadow mask for a color CRT tube which has been formed in a temperature of about 400 to 600 ° C. and a low pressure nitrogen gas atmosphere as a cathode, and a vacuum vessel as an anode. In this way, when a voltage is applied, a glow discharge occurs around the shadow mask to activate a nitrogen atom, and the activated nitrogen atom penetrates the surface of the shadow mask to react with iron (Fe), a supporting metal, to form an ε phase ( Fe _2-3 N) or the r phase (Fe ₄ N) is formed. In addition, by adjusting the ratio of nitrogen gas, it is also possible to generate a single phase. As such, when the nitride layer is formed on the surface, the temperature is reduced to room temperature, and then the shadow mask is taken out into the atmosphere, thereby producing the enhanced shadow mask of the present invention. The shadow mask thus prepared is installed in a color CRT through a normal degreasing and blackening process.

2) Strengthening the shadow mask by boron

A voltage of 400 to 800 V is applied using a shadow mask for a color CRT tube which has been formed in a temperature of about 400 to 600 ° C. and a BCl ₃ gas and a plasma generating gas as a cathode, and a vacuum vessel as an anode. As the plasma generating gas used, hydrogen and argon gas may be used. As such, when a voltage is applied, a glow discharge occurs around the shadow mask to activate the boron atoms, and the activated boron atoms penetrate the surface of the shadow mask to form a boron precipitate layer. As such, when the boron precipitate layer is formed on the surface, the temperature is lowered to room temperature, and then the shadow mask is taken out to the atmosphere, thereby producing the enhanced shadow mask of the present invention. The shadow mask thus prepared is installed in a color CRT through a normal degreasing and blackening process.

3) Reinforcement of shadow mask by carbon

A temperature of about 800 to 1000 ° C., a pressure of 0.1 to 10 torr, and a shadow mask for a color CRT tube formed in a hydrocarbon gas and a plasma generating gas atmosphere as a cathode, and a vacuum vessel as an anode immediately before 400 to 600 V. A high pressure is applied. As the hydrocarbon gas to be used, methane, propane or a mixed gas thereof may be used, and as the plasma generating gas, hydrogen and argon gas may be used. When this voltage is applied, as in the abnormal glow discharge at the periphery of the shadow mask (abnormal glow discharge) is generated, impinges on the surface at this time is accelerated proton (H ₂ ⁺⁾ The shadow mask to remove the oxide, or deposit the other hand, Thermally activated carbon is captured and diffused by surface catalysis, and carbon ions (C ⁺ ) collide with the surface of the shadow mask to attach or diffuse inward, and accelerated carbon ions impinge on the surface and directly inside. And penetrate lattice defects and form a carburized layer on the surface of the shadow mask due to the sputtering effect by argon. As such, when the carburized layer is formed on the surface, the temperature is reduced to room temperature, and then the shadow mask is taken out into the atmosphere to prepare the enhanced shadow mask of the present invention. The shadow mask thus prepared is installed in a color CRT through a normal degreasing and blackening process.

Preferred Embodiment

Preferred examples and comparative examples of the present invention are described. However, the following examples are merely examples of the present invention showing the constitution and effects of the present invention, and the present invention is not limited to the following examples.

Example 1

A voltage of 500 V was applied using a shadow mask for a color CRT tube, which was completed in a nitrogen gas atmosphere at a temperature of 500 ° C. and a low pressure, as a cathode, and a vacuum vessel as an anode. After 1 hour after the voltage was applied, the temperature was lowered to room temperature, and then the shadow mask was taken out into the atmosphere to prepare the enhanced shadow mask of the present invention.

Example 2

A temperature of 550 ° C., a BCl ₃ gas, and a plasma generating gas were applied as a cathode for a color mask tube for forming a colored CRT tube in a hydrogen and argon gas atmosphere, and a voltage of 600 V was applied to the vacuum container as an anode. After 1 hour after the voltage was applied, the temperature was lowered to room temperature, and then the shadow mask was taken out into the atmosphere to prepare the enhanced shadow mask of the present invention.

Example 3

A temperature of 900 ° C., a pressure of 3torr and a shadow mask for a color CRT tube formed in a atmosphere of hydrogen and argon gas as a methane and propane gas and a plasma generating gas as a cathode, and a vacuum vessel as an anode immediately before 600V. A high pressure was applied. After 1 hour after the voltage was applied, the temperature was lowered to room temperature, and then the shadow mask was taken out into the atmosphere to prepare the enhanced shadow mask of the present invention.

Comparative Example 1

Forming (forming) in an atmosphere of a temperature of 590 ℃ and NH ₃ gas was applied to the complete color CRT with a shadow mask and a cathode, just before the high-pressure flow of 600V to the vacuum chamber as an anode. After 1 hour after the voltage was applied, the temperature was lowered to room temperature, and the shadow mask was taken out into the atmosphere to prepare a shadow mask.

Various characteristics of the shadow mask manufactured by the method of the above Examples and Comparative Examples and conditions on the manufacturing method are shown in comparison with Table 1 below.

As a result of manufacturing the shadow masks by the method of Examples and Comparative Examples of the present invention, as can be seen in Table 1, the shadow mask of the present invention has a lower processing temperature than the conventional shadow masks manufactured using the gas nitriding method. In addition, it showed excellent economical characteristics that required less processing time. As described above, it can be seen that the strain rate after the strengthening treatment is low due to the low treatment temperature, resulting in lowering the defective rate. And the shadow mask strengthening method of the present invention can be easily in-line (in-line) of the treatment process, easy to control the thickness of the compound layer formed on the surface, it is possible to improve the product life due to the prevention of grain boundary oxidation.

In addition, it is also excellent in elastic modulus and tensile strength, and as a result, it can be seen that the color CRT using the shadow mask of the present invention can prevent the screen shaking and the deterioration of color purity due to external vibration and the like. In particular, the method of manufacturing the shadow mask by the carburizing method has an additional advantage of easy management of carbon concentration, simple pretreatment, gloss surface, high carbon and complex carburizing, and preventing decarburization. It was confirmed that it has.

1 is a partial cross-sectional view of a color cathode ray tube showing a state in which the shadow mask is shaken up, down, left and right by an external impact to change the path of the electron beam.

Explanation of symbols on the main parts of the drawings

1: panel 2: phosphor 3: stud pin

4: spring 5: frame

6: shadow mask (before vibration) 7: shadow mask (after vibration)

8: Shadow Mask Hole (Before Vibration) 9: Shadow Mask Hole (Before Vibration)

10: electron beam 11: electron gun

P1: Light emitting position (before vibration) P2: Light emitting position (after vibration)

Claims (12)

A shadow mask for a color CRT tube used as a cathode, and a shadow mask for applying boron atoms to the surface of the shadow mask by glow discharge by applying a voltage to a vacuum vessel used as an anode, in which a BCl ₃ gas and a plasma generating gas are charged. Method of strengthening. The method of claim 1, wherein the voltage is 400 to 600V. The method of claim 1, wherein the shadow mask has a plurality of holes for passing the electron beam, and a forming process for forming curvature is completed. The method of claim 1, wherein the method of strengthening the shadow mask proceeds at a temperature of 400 to 600 ℃. The method of claim 1, wherein the plasma generating gas is hydrogen or argon. A shadow mask for coupling carbon atoms to the surface of the shadow mask by an abnormal glow discharge by applying a voltage to a vacuum mask used as an anode, which is filled with a shadow mask for a color CRT tube used as a cathode and a hydrocarbon gas and a plasma generating gas. How to tighten the mask. 7. The method of claim 6, wherein said voltage is between 400 and 600 volts. The method of claim 6, wherein the shadow mask has a plurality of holes for passing the electron beam, and a forming process for forming curvature is completed. The method of claim 6, wherein the method of strengthening the shadow mask proceeds at a temperature of 800 to 1000 ℃. The method of claim 6, wherein the plasma generating gas is hydrogen or argon. 7. The method of claim 6, wherein the hydrocarbon gas is selected from the group consisting of methane, propane, and mixtures thereof. The method of claim 6, wherein the glow discharge proceeds at a pressure of 0.1 to 10 torr.

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