JPH10321136A - CRT manufacturing method - Google Patents

Abstract

(57) [Summary] [PROBLEMS] Due to an increase in the size of a cathode ray tube, exhaustion of a valve in an exhaustion process becomes insufficient, and the cathode ray tube life becomes a problem. A gas maintained at a maximum temperature in an exhausting process for a predetermined time exhausts all gas desorbed when a valve is heated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a black-and-white or color CRT, a color display tube, etc.
The present invention relates to a method for exhausting gas (unnecessary gas) discharged from each part in a pipe.

[0002]

2. Description of the Related Art As described in Japanese Patent Application Laid-Open No. 2-75129, a method of manufacturing a color cathode-ray tube generally performs baking (panel baking) after forming a fluorescent film on an inner surface of a panel. Attach parts such as shadow mask and inner sill. In addition, a conductive layer or the like is coated on the inner surface of the funnel. Next, after bonding the panel and the funnel with a bonding agent (frit glass), an electron gun is attached. Thus, the valve is assembled. Next, the gas in the valve is exhausted, and aging is performed to complete the color CRT. Exhaust gas released from various parts inside the valve while heating at a predetermined heating rate (unnecessary gas)
Is carried out to discharge the gas outside the valve and increase the degree of vacuum in the valve.

FIG. 3 shows the structure of the exhaust gas. The valve 3 is covered with a heating furnace 11, and a tip tube 6 protruding from a neck tube 4 on which an electron gun 5 is mounted is connected to a vacuum pump 1 via a conduit 14.
Connect three. The gas in the valve 3 passes through the tip tube 6,
The gas is exhausted from the conduit 14 by the vacuum pump 13. The evacuation capacity of the device shown in FIG. 3 is limited by the small part of the flow conductance. The neck tube 4 and the conduit 14 have a diameter of 30 mm
The tip tube 6 is a thin tube having a diameter of less than 10 mm. The conductance of the flow in the tip tube 6 is
And the conductance of the conduit 14 is 0.05 to 0.1 times, which is a part that determines the exhaust capacity of this device.

Conventionally, the temperature schedule at the time of exhaust is shown in FIG.
As shown by the bold solid line 23, the temperature was raised to the maximum temperature at a predetermined temperature raising rate, and the temperature was immediately set to fall. At this time, the temperature of the valve gradually rises as shown by the thin line 24 in FIG. 3, rises with a time delay from the set temperature, and is lowered without reaching the set maximum temperature.

[0005]

Heretofore, a phosphor film serving as a gas emission source has been formed by performing panel baking and then outgassing, or by subjecting iron parts such as a shadow mask to a surface treatment. Means for reducing the amount of gas release, such as preventing release, are employed. However, in recent years, as the demand for color cathode ray tubes and color display tubes has shifted to large tubes, gas emission has emerged as an important issue from the viewpoint of tube life and reliability. This is considered to be due to the fact that each component becomes large and the surface area increases due to the increase in size, and thus the amount of gas released during exhaust increases.

In other words, in FIG. 3, since the exhaust capacity is insufficient due to the small conductance of the tip tube 6, a part of the gas desorbed in the temperature increasing process enters the temperature decreasing process while remaining in the valve. It is presumed that the evacuation process has been completed with the residual gas adsorbed on components such as the fluorescent film and the shadow mask, or floating in the gas phase. Then, when such a valve is operated (electron irradiation), electrons collide with a fluorescent film, a shadow mask, or the like, and a gas is released. When the electron irradiation is stopped, the gas in the bulb is absorbed by the getter and decreases. The amount of gas desorbed by electron irradiation is larger than that of the conventional gas because the residual gas is adsorbed.

[0007] Therefore, by repeating the electron irradiation, the adsorption capability of the getter rapidly decreases, and the gas in the valve increases. This increasing gas leads to a short service life. It is considered that the gas desorbed by such a route has an adverse effect on the life of the cathode ray tube.

In order to improve the exhaust capacity, it is conceivable to increase the thickness of the tip tube 6. However, the diameter of the tip tube 6 is limited by the diameter of the neck tube and the structure of the electron gun. The current situation is extremely difficult.

SUMMARY OF THE INVENTION An object of the present invention is to solve the problems associated with the above prior art, and to provide a method of manufacturing a cathode ray tube having a long life by exhausting all the gas desorbed in an exhaust step. It is in.

[0010]

The above object is achieved by performing the evacuation step on a temperature schedule in which a maximum temperature set between a temperature increase and a temperature decrease is maintained for a predetermined time.

In the conventional exhaust process, the exhaust capability is determined by the tip tube 6 having the smallest conductance. Since a large pipe emits a larger amount of gas than a conventional pipe, all of the desorbed gas is not exhausted and a part remains in the valve. In particular, when the temperature is raised, the gas exhaust amount increases when the temperature is 100 ° C. or higher, so that at 100 ° C. or higher, the desorbed gas is always floating in the valve. While the temperature is rising, the gas in the valve repeats adsorption and desorption, and the ratio is higher for desorption. When the temperature falls after exceeding the maximum temperature, the ratio of desorbed gas decreases, and the amount of gas adsorbed on the component surface in the valve increases. By exhausting all the gas in the valve when the valve is at the maximum temperature, the amount of adsorbed gas can be reduced. Then, since the amount of gas emitted by the repetitive operation of electron irradiation decreases, the gas absorbing ability of the getter does not rapidly decrease.

An object of the present invention is to hold a valve at a maximum temperature, which is the final point of temperature rise, for a predetermined time, exhaust gas remaining in the valve while holding the valve, and enter a temperature decreasing process. An object of the present invention is to provide a method for manufacturing a CRT in which an exhaust process is performed on a temperature schedule.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is an explanatory view of a main part showing an exhaust device configuration, and FIG. 2 shows a temperature schedule at the time of exhaust.

A fluorescent film is formed on the inner surface of the panel 1, and a shadow mask or the like is attached. The inner surface of the funnel 2 is coated with a conductive layer or the like. Next, after bonding the panel 1 and the funnel 2 with frit glass (bonding agent), the electron gun 5 is sealed.
A thin tube (tip tube 6) necessary for exhausting gas in a later step is provided. In the process up to this sealing, baking is performed for the purpose of joining and degassing. Thus, the valve 3 is assembled. Next, the gas in the valve 3 is exhausted and aging is performed, and the color cathode ray tube is completed.

The valve 3 is covered with a heating furnace 11, and an exhaust device 10 of a vacuum pump is connected to a tip tube 6 protruding from a neck tube 4 on which an electron gun 5 is mounted. The exhaust device 10 includes, for example, a vacuum pump in which a rotary pump 9 and a turbo-molecular pump 8 are combined, and a conduit 7 for connecting to the tip tube 6. The heating furnace 11 includes the temperature control device 1
2 controls the temperature under a predetermined temperature schedule.

The gas in the valve 3 passes through a tip tube 6,
The gas is exhausted from the conduit 7 by the exhaust device 10. The neck tube 4 and the conduit 7 have a diameter of about 30 mm, and the gas in the valve 3 of the tip tube 6 is exhausted from the conduit 7 by the exhaust device 10 via the tip tube 6. The neck tube 4 and the conduit 7 have a diameter of 30
mm, and the tip tube 6 is a thin tube having a diameter of less than 10 mm. The conductance of the flow in the tip tube 6 is
And 0.05 to 0.1 times the conductance of the conduit 7,
The exhaust capacity of the exhaust system including the valve 3 and the exhaust device 10 is determined.

As described above, the configuration of the device is the same as that of the conventional device. The present invention is characterized by the temperature schedule of the heating furnace 11 controlled by the temperature control device 12. Hereinafter, the temperature schedule of the present invention will be described with reference to FIG.

The temperature schedule 21 to be set is to start heating from room temperature or a temperature higher than room temperature (about 100 ° C.), raise the temperature at a constant rate, hold the temperature at the maximum temperature Tm for a time ti, and lower the temperature. is there. The temperature change of the valve 3 at this time is shown by a thin line 22. The changes at the time of rise and temperature rise are the same as in the conventional case (24 in FIG. 4). Immediately after reaching the maximum temperature Tm, a slight overshoot occurs and the temperature is maintained at the maximum temperature Tm. All the gas desorbed at the time of temperature rise is exhausted during the held ti, so that it does not adsorb to the components in the valve 3.

The time ti at which the gas is maintained at the maximum temperature Tm is a time required for exhausting the gas in the valve 3. Time t
i (sec) is considered to be a time calculated as an exhaust system for exhausting gas having a volume V (l) of the valve 3 at an effective exhaust speed St (l / s) of the tip tube 6. Therefore, the amount of released gas at the highest temperature Tm is Q (Pa · m3 / s), and the amount of released gas when the pressure of the valve 3 is 1 Pa is Q1 (Pa · m3).
/ S), ti = (V / St) · ln (Q / Q
1) It is obtained from the following equation. Here, the effective pumping speed St
Uses the value of the portion of the exhaust system having the minimum conductance. The released gas amount Q1 is an initial condition of the exhaust system. As an example, when a 10-liter valve is evacuated at the maximum temperature Tm = 400 ° C., the holding time ti is about 600 seconds. From this value, it can be seen that the holding time ti of the temperature schedule should be set to 10 minutes or more.

From the above, since the gas absorption capacity of the getter is not rapidly deteriorated even when the electron irradiation is repeated, the change with time in the pressure in the bulb 3 becomes extremely small, and a long-life cathode ray tube is achieved. .

[0021]

In the method for manufacturing a cathode ray tube, all the gas in the bulb is exhausted by holding the bulb at the maximum temperature after the temperature rise in the exhaust process for a predetermined time, and the gas desorbed at the time of temperature rise is adsorbed. Therefore, the change with time of the valve pressure due to repeated electron irradiation is extremely small, and there is an effect that a long life is achieved.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing exhaust of a CRT according to an embodiment of the present invention.

FIG. 2 is a diagram showing a temperature schedule of the present invention.

FIG. 3 is a configuration diagram of a conventional exhaust.

FIG. 4 is a diagram showing a conventional temperature schedule.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Panel, 2 ... Funnel, 3 ... Valve, 4 ... Neck tube, 5 ... Electron gun, 6 ... Chip tube, 7 ... Conduit, 10 ... Exhaust device, 11 ... Heating furnace, 12 ... Temperature control device.

Claims (1)

[Claims] 1. A panel on which a fluorescent film made of a phosphor layer or the like is formed on the inner surface and a funnel having a conductive layer or the like formed on the inner surface is joined to a panel provided with a shadow mask or the like, and an electron gun is mounted. A method of exhausting gas in a valve by using an exhaust device, wherein the valve is heated at a predetermined heating rate, held at a maximum temperature for a predetermined time, and then exhausted according to a temperature schedule for decreasing the temperature. Method.