JPH02174036A - Manufacture of cathode-ray tube - Google Patents

Abstract

PURPOSE:To suppress the oxidation of constituting electrodes by substituting the contaminated gas in an envelope with inert gas into the oxidation-resistant atmosphere with specific oxygen concentration and dew point. CONSTITUTION:An envelope 1 is moved through a baking furnace and baked for the main purpose to burn and remove a lacquer filming film as a residue made unnecessary by the formation of an aluminum film. Inert gas 5 as uncontaminated gas is guided through a hole 4a via a nozzle 4 and introduced into the envelope 1. The atmosphere in the envelope after the substitution by inert gas 5 is set to the oxygen concentration of 10% or below and the moisture quantity with the dew point of -5 deg.C or below into the oxidation-resistant atmosphere. The oxidation of constituting electrodes of an electron gun by the subsequent high-temperature heat treatment process can be suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method of manufacturing a cathode ray tube, and more particularly to a method of manufacturing a cathode ray tube, in which oxidation of electric scratches and the like constituting an electron gun is suppressed as much as possible.

[Conventional technology]

A conventional method for manufacturing a cathode ray tube will be explained based on the drawings. In the figure, reference numeral 1 denotes an envelope of a cathode ray tube, including a panel part la for screen display, a conical funnel part 1b for forming an anode, and a cylindrical part opened to receive a stem and an electron gun. It consists of a neck IC.

In forming the envelope 1, a fluorescent film 2 for display is coated on the inner surface of the panel portion 1a, and an internal conductive film 3 for an anode is coated on the inner surface of the funnel portion 1b to which the neck portion 1c is connected. It is formed. The funnel part 1b is connected at its larger end to the panel part 1a by a frit seal to form the envelope 1. Note that an aluminum film (not shown) is deposited as a metal bank on the exposed surface of the fluorescent film 2, and in order to obtain smoothness of this aluminum film, lacquer filming is applied in advance. . After forming the aluminum film by vapor deposition, the rough car filming film (not shown) is unnecessary, so the envelope 1 is passed through a baking furnace adjusted to a temperature of about 350°C to 400°C. The rough car filming film is removed by incineration, but the incineration gas generated inside the envelope 1 due to this incineration is not only the incineration gas of the rough car filming film but also the fluorescent film 2 and internal conductive film 3. The included impurity incineration gas is also included. Normally, after completing the above-mentioned baking process and before performing electron gun sealing to attach an electron gun (not shown) to the neck IC, the envelope 1 is The gas inside is being replaced.

This gas replacement is disclosed in, for example, Japanese Utility Model Publication No. 19903/1983. According to this method, a nozzle 4 having a hole 4a formed at its tip for introducing non-contaminant gas is inserted from the open end of the neck IC, and the non-contaminant gas is passed through the nozzle 4 from the hole 4a. By drawing out the non-polluting gas, the envelope 1 is introduced and filled with the non-polluting gas, thereby performing gas exchange within the envelope 1. It is disclosed that air is used as the non-polluting gas, and that room temperature air having a dew point of -16°C is preferred.

After exchanging the gas as described above, the sealing temperature is 700℃~
Mount the electron gun at 900°C. After the electron gun is sealed, evacuation and baking are performed to remove the filled gas and degas the electrodes. Furthermore, the cathode is activated and the exhaust pipe is sealed off. Note that gettering is performed as necessary.

Recently, a sputtered arc shield (hereinafter referred to as SAS), which suppresses discharge within a cathode ray tube, has been developed by providing an arc shield on the electron gun focus electrode and vacuum depositing a part of this arc shield material on the inner wall of the neck IC. ) is being carried out.

[Problem to be solved by the invention]

The conventional manufacturing method for cathode ray tubes is as described above. After replacing the inside of the envelope 1 with air, which is a non-contaminating gas, the electron gun is sealed at a high temperature. is oxidized by reacting with oxygen etc. in the envelope 1, and even if the cathode is activated in the subsequent process, the initial emission is small and a large current is required with the normal amount of current to the cathode. There was a problem that the lifespan of the cathode ray tube was shortened.

In addition, the arc shield material for SAS oxidizes,
There were problems such as the inability to perform vacuum evaporation.

This invention was made in order to solve the above-mentioned problems, and provides a method for manufacturing a cathode ray tube that can reduce oxidation of the electron gun component metal during sealing of the electron gun and ensure reliability in terms of service life. The purpose is to obtain.

[Means for solving problems].

A method for manufacturing a cathode ray tube according to the present invention includes a step of baking an envelope, a step of replacing the inside of the envelope with a non-contaminating gas, and a step of sealing an electron gun after the replacement. In this method, an inert gas is used as a non-contaminating gas, and the atmosphere after replacement is adjusted to an oxygen concentration of 10% or less and a moisture content of 15%.
The dew point is below ℃.

[For production]

In the method for manufacturing a cathode ray tube according to the present invention, the atmosphere inside the envelope after replacement with an inert gas is made into an oxidation-resistant atmosphere with an oxygen concentration of 10% or less and a moisture content of a dew point of -5°C or less. Oxidation of the constituent electrodes of the electron gun due to subsequent high-temperature heat treatment steps such as electron gun sealing is suppressed as much as possible.

(Example〕 Hereinafter, one embodiment of the present invention will be described based on the drawings.

In the figure, an envelope 1 of a cathode ray tube is composed of a panel section 1a, a funnel section 1b, and a neck section 1c.A fluorescent film 2 is coated on the inner surface of the panel section 1a, and a rough car filming film is formed on the exposed surface of the panel section 1a. An aluminum film is formed by vapor deposition through the funnel portion 1b, and an internal conductive film 3 is formed by coating on the inner surface of the funnel portion 1b. Since the steps up to this point are well known, detailed explanation will be omitted. The above-mentioned envelope 1 was heated to 350°C to 400°C with the main purpose of incinerating and removing the lacquer filming film as a residue that became unnecessary due to the formation of the above-mentioned aluminum film.
The sample is passed through a baking oven heated to a temperature of .

After completing the above baking process, CO□
Incineration gas exists as a polluting gas containing oxidizing gases such as , (2) 20, and various other gases.

Next, a nozzle 4 having a hole 4a is inserted into the tip from the open end of the neck portion 1c, and the hole 4a is located at the center near the boundary between the panel portion 1a and the funnel portion 1b. Activated gas 5 is passed through nozzle 4, led out from hole 4a, and introduced into envelope 1. As the amount of the inert gas 5 introduced increases, the incineration gas is expelled to the outside from the open end of the neck portion 1c. After filling the envelope 1 with an appropriate amount of inert gas 5, the nozzle 4 is taken out from the envelope 1 and the next step is carried out. The amount of inert gas 5 introduced must be 1.5 times or more the internal volume of the envelope 1. Further, as the inert gas 5, for example, N2 gas is generally used.

After replacing the gas as described above, well-known steps such as sealing the electron gun, evacuation, baking, activating the cathode, and sealing off the exhaust pipe are sequentially performed.

In the various experimental results in the above examples, inert gas 5
After introducing into the envelope 1, the atmospheric conditions in the envelope 1 are set such that the oxygen gas concentration is 10% or less, and the moisture content of the atmosphere in the envelope 1 is set to a dew point of 5°C or less. do it. In this way, the electrodes constituting the electron gun will be less likely to be oxidized at temperatures of 700°C to 900°C during electron gun sealing, and the cathode will be sufficiently activated in the exhaust process and aging process that will be carried out later. A cathode ray tube with good initial emisocillin and less trouble during life can be obtained. In addition, there is almost no oxidation of the arc shield material used in SAS (neck IC
This arc shielding material can be easily vacuum deposited on the inner wall.

In addition, when N2 gas is used as the inert gas 5, in order to achieve the above atmospheric conditions inside the envelope 1, the moisture content of the N2 gas must be kept at a low dew point of -40°C or less. good.

Alternatively, the gas replacement method may be a two-stage method, in which the inside of the envelope is replaced with low dew point air in the first stage, and the inert gas is introduced into the envelope in the second stage. This replacement method applies impact and vibration to the outside of the envelope and removes dust generated inside the envelope to the outside of the envelope in the first stage.

Next, the results of various tests on a 14-inch color cathode ray tube (inner volume approximately 7.51 cm) are shown in the table below.

In the above table, test numbers 1 to 5 are one-step substitution method,
Test floors 6-1IkL8 were tested using different displacement gases.
This is a stepwise replacement method. In the results in the table, if good results were obtained in reducing oxidation of electron gun constituent metals and improving reliability such as life span, mark O, if not so good, mark Δ, and if bad, mark X. It shows. The parts not described in the tube conditions indicate that the conditions for keeping the oxygen concentration in the tube at 10% or less and keeping the moisture content of the atmosphere inside the tube at a dew point of -5° C. or less are not met. The present invention was applied to Test No. 5 and Test No. 8, and good results were obtained in both cases.

In test II & 18, air with a dew point of -15°C was first flowed into the envelope L for 30 seconds at a flow rate of 201/l1in to remove dust inside the tube, and then nitrogen gas with a dew point of -40°C was introduced into the envelope L for 30 seconds. It is replaced by flowing it into the envelope 1 for 30 seconds at a flow rate of R/min. As a result, the atmosphere inside the tube has an oxygen concentration of I
The dew point was below 0% and the moisture content was below 15°C. The well-known steps described above are performed before and after this two-stage gas replacement.

Note that the position and shape of the nozzle inserted into the envelope, and the ejection direction of the introduced gas may be of any type as long as they satisfy the atmospheric conditions within the envelope in the above embodiments.

Further, the present invention is not limited to the type of occultation tube, such as black and white or color. Also, the gas inside the envelope can be replaced at any time after the baking process of the envelope and before the electron gun sealing process, but it is about 2 hours after the gas chamber l# and before the electron gun sealing process starts. If it takes longer than that, cover the opening on the neck side so that the atmospheric conditions inside the envelope do not change due to changes in the temperature conditions of the envelope, etc., and keep it constant. It is desirable to leave it there.

〔Effect of the invention〕

As described above, according to the present invention, the contaminant gas in the envelope is replaced with an inert gas, and the atmosphere in the envelope is maintained at a dew point with an oxygen concentration of 10% or less and a moisture content of 15°C or less. This creates an oxidation-resistant atmosphere and suppresses the oxidation of the electrodes forming the electron gun as much as possible during the subsequent heat treatment process, thereby suppressing oxidation of the cathode due to electron gun sealing and eliminating life-span troubles. This has the effect of preventing oxidation of the arc shield material for SAS and facilitating its vapor deposition.

[Brief explanation of the drawing]

The figure is a partially cutaway sectional view showing the process of the main part according to an embodiment of the present invention. In the figure, 1...Envelope, 1a...Panel part, 1b...
- Funnel part, 1c... Neck part, 2... Fluorescent film, 3... Internal conductive film, 4... Nozzle, 4a... Hole. Agent Masuo Oiwa

Claims (1)

[Claims] a step of vaporizing the residue in the envelope; a step of replacing the polluting gas generated by the step with a non-contaminating gas to eliminate it outside the envelope; In the method for manufacturing a cathode ray tube, the method includes the step of sealing electrons and guns in the neck portion, in which the non-contaminating gas is replaced with an inert gas, and the oxygen concentration in the envelope is reduced to 10% or less. A method for manufacturing a cathode ray tube, characterized in that the moisture content of the atmosphere inside the envelope is set to a dew point of -5°C or lower.