JPS58184237A - Manufacture of cathode-ray tube - Google Patents

Abstract

PURPOSE:To make the gas coming from a pannel being dissolved during heat treatment to be burnt by feeding air by a method wherein wavelike unevenness is formed on the surface of a frit layer on the funnel seal surface in order to form through holes when the pannel is placed thereon. CONSTITUTION:A frit layer 3 is formed by coating the seal surface 2 of a funnel 1 applied with graphite with the paste, wherein a rehicle consisting of an organic binder and an organic solvent is kneaded with frit powder, while wavelike unevenness with a pitch of 5-10mm. is formed by pressing a metallic mold or the like at every interval of the material in an intermediate dry state proceeding on the frit layer. Next, a panel 4 and the funnel 1 incorporated in a frame are transferred into a mesh belt type sealing furnece to be raised in temperature up to about 380 deg.C at the temperature rising rate of about 10 deg.C. Thereby the quantity of oxygen contained in the air inside of a tube is short by about 20% as compared with the quantity of oxygen required to burn completely organic substances of the panel. However, the lacking oxygen can be supplied by throughholes 5 which are formed by wavelike unevenness provided on the frit layer and piercing in-and-outside of the tube.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a cathode ray tube, and particularly relates to an improvement in the heat treatment process.

Generally, a color cathode ray tube consists of a glass panel part, a seven-hole part including a funnel part, and a neck part.It has an electron gun that can emit multiple beams in a vacuum container, a shadow mask structure for color selection, a fluorescent surface, etc. Contains.

The manufacturing process for such color cathode ray tubes usually includes at least four heat treatment steps.

The first step is a pre-baking step for thermally stabilizing the panel structure, which is a combination of a panel without a fluorescent surface coated and a shadow mask. The second step is a firing step in which the organic components are burned off from the panel on which the fluorescent surface has been formed.

The third step is a step of sealing the fired panel and the funnel portion via frit glass.

The fourth step is a step of evacuation of the encapsulated pulp in which an electron gun is encapsulated in the encapsulated pulp.

In these heat treatment processes, the object to be heated is usually automatically sent into the furnace from the furnace entrance using a dolly or mesh belt.
The heat treated material is taken out of the furnace according to a preset temperature schedule crystal. Thereafter, the object to be heated is processed or inspected, and then sent to the next heat treatment step. If there are many such heat treatment furnaces, there will be disadvantages such as a large amount of energy is required for raising and lowering the temperature, a long working time, a large working space is required, and corrosion occurs during storage of the fired panels.

The present invention has been made to prevent the above-mentioned drawbacks.
The sealing process and the firing process are performed in one furnace (sealing furnace) for the purpose of omitting the firing process.

In order to achieve this objective, in the present invention, wavy irregularities are formed on the surface of the slit layer provided on the sealing surface of the funnel, so that when a panel is placed on the seven slit layers, the inside and outside of the vacuum container are separated. Through-holes are formed to connect the panels, and air is supplied to replenish the gas decomposed from the panel during heat treatment so that it can be combusted.

The present invention will be explained in detail below.

The inside of the funnel is subjected to a chemical cleaning treatment using acid or alkali, etc., and the funnel-shaped part and neck part of the funnel, which have been washed and dried with pure water, are coated with interior graphite and neck graphite, respectively, and then dried.

Next, as shown in Figure 1, the funnel 1 coated with graphite is
A frit layer 3 is formed by coating the seal [2] with a paste prepared by kneading a vehicle consisting of an organic binder, an organic solvent, and frit powder.

7 lits in an intermediate dry state, i.e. coated frit layer 3
To the extent that molding is possible and paste does not adhere when an appropriate object is pressed against the material.

In this intermediate dry state, a metal mold or the like is pressed against the frit layer to form wavy irregularities with a pitch of 5 to 10 mm. After drying the VK7 lit layer, the funnel is attached to a sealing frame, and the panel 4 is placed on top of it. At this time, a large number of through holes 5 that pass through the inside and outside of the tube are formed between the panel and the funnel.Next, the panel and funnel assembled in the frame are sent into a Metshim belt type sealing furnace where the temperature rises by about 10°C. Temperature speed is about 380
The temperature is raised to ℃. When a valve moves in a furnace, it is inevitably accompanied by some vibration, but in the present invention, the panel is rounded and supported by a number of convex centerpieces, and the panel is not displaced relative to the funnel. Never. Approximately 380
Keep it at ℃ for 30 minutes to completely burn the organic matter on the fluorescent surface formed on the inner surface of the panel. At this time, the amount of oxygen necessary to completely burn the organic matter on the panel is about 28% insufficient from the amount of oxygen contained in the air inside the tube, but the tube formed by the undulating unevenness in the frit layer The missing oxygen is replenished by the holes penetrating the inside and outside of the tank. In other words, the gases generated when the organic matter contained in the fluorescent film decomposes or burns are charcoal gas, water vapor, monomers, aldehydes, etc., and most of them are heavier than air, so these gas components are concentrated in the lower part of the neck. and is released outside the tube. On the other hand, contrary to the movement of these gas components, air, which is lighter than these gas components, is replenished through the through holes formed between the panel and the funnel, and the oxygen necessary for complete combustion is replenished inside the valve. The oxygen supplied in this manner prevents the lead oxide in the frit component from being reduced to lead by the reducing gas decomposed from the panel.

Next, the temperature was raised to 450°C at a rate of about 10°C, and kept at that temperature for about 60 minutes to melt the frit glass and eliminate the through hole formed between the panel and funnel, and submerge the panel to seal it. I do.

Next, the temperature of the sealing valve is lowered at a rate of about lθ°C, and the sealing is completed by taking it out of the furnace.

In the present invention, the period of the wavy irregularities is approximately 5 to 1Qmm, so for example, in the case of a 20-inch color cathode ray tube, the periodicity of the wavy irregularities is at least 100 mm over the entire sealing surface of the funnel.
Since it is possible to form wavy irregularities in more than one place, the panel is supported at multiple points, so it will not shift due to vibrations when the valve moves on the mesh belt in the furnace, and the panel will be stable at about 380℃. Even during the decomposition of organic matter, the panels will not collapse under their own weight and the through holes will not become blocked.

Furthermore, even when the temperature is further increased and the frit melts and the panel sinks, the panel is prevented from shifting. Furthermore, since the pitch of the concavities and convexities is small, the frit can be completely moved to the concavity even when 7 nits are melted, and the uniformity of the frit molten layer after sealing is completed is maintained.

As explained above, in the present invention, a frit glass paste is applied to the cool part of the funnel, and in an intermediate dry state, a large number of wavy irregularities are formed, and when a panel is placed on top of the paste, the paste is applied to the cool part of the funnel, and the paste penetrates the inside and outside of the tube. The holes allow air to be supplied during the decomposition of organic matter in the panel, making it possible to perform the two steps of firing and sealing in the sealing furnace, essentially eliminating the need for a firing furnace. Ta.

In the above description, the frit layer is formed on the Noah/Flannel base, but it may also be sintered into a ring shape as shown in FIG. 2.

[Brief explanation of the drawing]

! ! Figure 1 is a schematic diagram of an embodiment of the present invention, and Figure 2 is a top view of a sintered frit ring. 1...Funnel, 2...Seal surface,
3...Frit layer, 4...Panel. 1st mouth 2nd close 175

Claims (1)

[Claims] In a method for manufacturing a cathode ray tube including at least a KIIE sub-gun and a fluorescent surface inside a glass vacuum container, a frit layer having wavy irregularities extending along the seal portion is formed on the surface of the seal portion of a funnel forming the vacuum container; A method for manufacturing a cathode ray tube in which panels are stacked on seven lit layers and fired and sealed in one continuous furnace.