JPH044682B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a cathode ray tube that uses a frittable getter and provides good electron emission characteristics.

In the conventional manufacturing method for cathode ray tubes, while the cathode ray tube is heated in an exhaust furnace, the gas inside the tube is evacuated through an exhaust tube called a chip tube using an external high-vacuum exhaust device. No operation was performed, but the exhaust pipe was welded (chip-off) and cut at the exit of the exhaust furnace, and then a getter flush was performed using high-frequency induction heating or the like. However, when attempting to reduce the number of man-hours by sealing the valve panel and funnel with fritted glass at the beginning of the exhaust process, the conventional getter (barium) is It changes in quality when heated above ℃, and it no longer functions effectively as a getter even if it is flashed after chip-off. On the other hand, recently developed frittable getters are coated with organic silane and can withstand firing in air. There is a significant incidence of tubes in which the organosilane coating decomposes and gasifies (prior to the formation of the cathode) and thus degrades the electron emitting properties of the cathode.

The object of the present invention is to use a frittable getter,
Moreover, it is an object of the present invention to provide a method for manufacturing a cathode ray tube in which electron emission characteristics are not deteriorated.

In order to achieve the above object, in the present invention,
Before chip-off, the frittable getter is preheated, and gases from the decomposition of the organic silane coating and other gases that are adsorbed in the getter and released before the getter evaporates are removed from the exhaust pipe using an external high-vacuum exhaust system. After thorough removal through the exhaust pipe, we decided to perform an exhaust pipe tip-off, followed by a getta flush.

The present invention will be further explained below with reference to the drawings. The present inventor first conducted an experiment to find that in the conventional method, that is, a method in which the getter is flushed after chip-off without preheating the getter, the degree of vacuum in the tube immediately after the getter flush is lower than that of the conventional getter when a frittable getter is used. It was confirmed that the performance was about one order of magnitude worse than when using the same method. This may indicate that there is a problem with the gas generated when the frittable getter is flashed, so the vapor pressure of the getter material itself (barium) is still low (so Furthermore, the organic silane coating was heated to a temperature at which it reliably decomposed and vaporized, and the gas generated was investigated. An example is shown in FIG. in these gases
It is thought that CH ₄ , CO _{2 ,} etc. are likely to affect the electron emission characteristics, but methane CH ₄ in particular has a slow adsorption speed by the barium getter, and when it comes into contact with the cathode surface during aging, it attaches carbon and deteriorates the electron emission characteristics. It is thought to be the culprit. Based on such experiments, in the present invention, the frittable getter is preheated before chip-off, and the decomposed gas of the organic silane coating and the gas normally occluded by the barium getter are evacuated using an external high vacuum pumping device. They decided to remove it thoroughly by passing it through a tube.

The preheating conditions are to remove the organic silane coating originally applied to protect the getter from high-temperature atmospheres, so it is necessary to perform the preheating after the vacuum inside the tube is high, that is, at about 10 ^-5 to ^{10 -6} Torr. There is,
Preheating is meaningless unless the lower limit of the heating temperature is higher than the maximum temperature of the valve during exhaust gas heating, and the upper limit of the heating temperature is considered to be 700℃ or less in order to make the original getter function work effectively, so it ends up being 400 to 600℃. Approximately 5 minutes is appropriate.

As a result of performing preheating, it was possible to suppress the defective electron emission characteristics, which conventionally sometimes occurred by 20 to 30% when using a frittable getter, to 0.5% or less. Although conventional barium getters have not been preheated, stable electron emission characteristics can be obtained even in tubes using normal (non-frittable) getters by preheating the getters during the evacuation process. It will be done.

As explained above, according to the present invention, a cathode ray tube with good electron emission characteristics can be reliably manufactured using a frittable getter.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the gas release state when the frittable getter is heated to 600°C.

Claims (1)

[Claims] 1. When evacuating a cathode ray tube equipped with a frittable getter made of organosilane-coated barium,
While the inside of the cathode ray tube and the external high vacuum evacuation device are communicating through the exhaust pipe, the frittable getter is heated at 400 to 600°C at a vacuum degree of 10 ^-5 to ^{10 -6} Torr inside the cathode ray tube. Preheat for about 5 minutes,
A method for manufacturing a cathode ray tube, characterized in that the gas generated by this heating is sufficiently removed in advance, an exhaust pipe tip-off is performed, and then a getter flush is performed.