JPH01225038A - Sealing device for cathode-ray tube - Google Patents

Abstract

PURPOSE:To precisely and surely weld a stem body structure and the opening end of a neck section by inserting the first heater with the sufficient heating capability in a mount pin fitted with a stem body structure and providing the second heater on the outer periphery of the mount pin. CONSTITUTION:A mount pin 20 is provided with a mount pin base 21 with a smoothly formed top face in particular on its top section so that a stem body structure mounted with an electron gun body structure can be correctly fitted to it. The first heater 22 with the sufficient heating capability is inserted into the mount pin 20, the second heater 23 is provided on the outer periphery of the mount pin 20. The mount pin has little portion directly exposed to the outside air, even if a sharp change of the outside air temperature occurs, the mount pin base is heated with little effect from it. The stem of a stem body structure fitted to the mount pin base can be welded to the neck section opening end of a cathode-ray tube at the optimum heating temperature. The stem body structure and the cathode-ray tube neck section can be surely and precisely welded.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention involves welding a stem structure carrying an electron gun structure to the neck portion of a glass bulb in which an internal fluorescent surface is formed.
This invention relates to a sealing device for a cathode ray tube.

[Conventional technology]

Generally, in step 1 of the manufacturing process of cathode ray tubes, after a fluorescent surface, graphite electrodes, and other necessary electronic parts are installed inside the glass bulb, a stem with an electron gun mounted on the open end of the neck of the glass bulb is attached. There is a process of welding the structure and sealing it. Such a sealing method is disclosed in, for example, Japanese Patent Publication No. 31595/1983.

Normally, to seal a cathode ray tube, a large number of sealing holders are placed on the outer edge of a disc-shaped turntable, and the turntable is rotated in steps. The process of heating the open end of the neck of the cathode ray tube held in the sealing holder and welding the stem structure mounted on the mount pin to the open end of the neck of the cathode ray tube one after another is carried out one after another. .

Figure 2 shows the external appearance of the cathode ray tube before sealing. 1 is the panel, 2 is the funnel, and 3 is the neck. The neck 3 is cut by melting at C during the sealing process, and the flared part of the neck is cut by melting. The part containing 4 is called the force Vt.

In recent years, with the advancement of sealing technology, so-called cullet-less cathode ray tubes, in which the neck portion 3 is cut in advance at position D, as shown in the external view in Figure 3, have become widely used. Became.

This type of cathode ray tube sealing device will be described below.

Conventionally, culletless cathode ray tubes were sealed by heating and softening the open end of the neck with a gas burner, pressing the stem heated to a constant temperature against the C, and welding the stem and the open end of the neck. The sealing process is completed by pulling the stem and shaping the weld between the stem and neck.

However, the heating position and the flame state of the burner in the above process are easily affected by external disturbances, making it difficult to perform highly accurate heating processing. A heating device has been proposed that uses a heater using pin lamination heat (hereinafter simply referred to as a heater).

FIG. 4 shows an example of welding the neck part of a cathode ray tube and a stem structure using a heater, and 6 is a sealing holder that holds the cathode ray tube to be sealed, and the turntable (not shown) is connected via a boat 8. It is placed on the outer peripheral end surface of.

Reference numeral 9 denotes a culletless neck portion, and 10 a mount pin, at the top of which is provided a mount pin cap 11 with a particularly smooth top surface, on which is attached a stem structure 13 on which an electron gun structure 12 is mounted. .

In such a configuration, as shown in the sectional view of the main part of the sealing device in FIG. 5, first, the stem assembly 13 is roughly adjusted and mounted on the mount pin base 11. and,
Move this upward and insert it into the valve neck part 9,
After positioning the electron gun assembly 12 at a predetermined height, the open end of the neck portion 9 and the mount pin base 11 are heated by heaters 14, 15 & 2 so that they are at a constant temperature, and the stem of the stem assembly 13 is heated. 17 is welded to the open end of the neck portion 9.

In the above case, in order to particularly ensure that the open end of the neck portion 9 and the stem 17 are welded together, they are kept at approximately the same temperature. Therefore, as shown in FIG. 5fb), a plurality of heaters 15 are loaded into the mount pin 10, thereby heating the mount pin cap 11 and bringing the temperature of the stem 17 to a predetermined temperature. It consists of

[Problem to be solved by the invention]

According to the conventional technology described above, the opening end of the neck portion 9 is surrounded by the heater 14 and there is little direct contact with the outside air, so the heating temperature at this portion is not easily affected by changes in the outside air temperature and is quite high. Accurate temperature control was possible.

However, since the heater 15 that heats the mount pin cap 11 is installed inside the mount pin 10,
The outer surfaces of the mount pin 10 and the mount pin cap 11 are in direct contact with the outside air, and therefore the heating temperature of both is easily affected by changes in the outside air temperature. The temperature at 17 was fluctuating considerably.

As a result, the heating temperature of the open end of the neck portion 9 and the stem 17 of the stem structure 13 is different, and the welding of the two becomes incomplete, resulting in large deformation of the welded part and making it impossible to achieve high-precision welding. There were drawbacks. Particularly, when the heating temperatures of the two are significantly different, problems such as the neck portion 9 or the stem 17 becoming easily cracked have arisen.

SUMMARY OF THE INVENTION In view of the above-mentioned conventional problems, it is an object of the present invention to provide a cathode ray tube sealing device that reliably welds a stem structure carrying an electron gun structure and an open end of a neck portion with high precision.

[Means to solve the problem]

The object of the present invention is to install a first heater having a sufficient heating capacity inside a mount pin on which a stem structure is attached, and also install a second heater on the outer circumference of the mount pin. achieved.

[Effect]

Since the present invention has the above-mentioned structure, there are few parts of the mount pin that come into direct contact with the outside air, and even if there is a wide change in outside air temperature, the mount pin base is less affected by it. is heated.

As a result, the stem of the stem structure attached to the mount pin base can be welded to the open end of the neck portion of the cathode ray tube at the optimum heating temperature, so that the above-mentioned problems related to welding of the two do not occur.

〔Example〕

An embodiment of the present invention will be described below with reference to FIG. 20
is a mount pin, and a mount pin base 21 having a particularly smooth top surface is provided on the top of the mount pin, and is screwed onto the mount pin cap 21 so that the stem structure on which the electron gun structure is mounted can be accurately mounted. A first heater 22 having sufficient heating capacity is loaded inside the mount pin 20. In this embodiment, the first heaters 22 each having a heating capacity of 40 W x 6 are loaded with a car, respectively, and are designed to be replaceable as appropriate.

Further, in the present invention, in particular, the second heater 23 is installed, which has a diameter of ζ on the outer circumference of the mount pin 20. In this example, 90W
A second heater 23 having a heating capacity of
In an atmosphere where the outside circumference is equipped with a band-like guard and the outside temperature changes rapidly, it is effective to further surround the outer circumference with a heat insulating material. In the figure, 24 is an insertion tube through which an exhaust pipe of a cathode ray tube is inserted.

The total heating capacity of the first heater 22 and the second heater 23 is sufficient to prevent the temperature of the mount pin base 21 from falling below, for example, 460°C even if the outside air temperature drops by a wide range. It is decided to have. In practical terms, the expected maximum heating load is 90% of the above total heating capacity.
For safety reasons, it is preferable to design the following.

Next, in order to keep the temperature of the mount pin base 21 constant,
A temperature control device that keeps the second heater 23 on at all times and controls the heating capacity of the first heater 22 by varying the temperature of the mount pin base 21 accordingly is suitable.

In order to perform such temperature control with an accuracy within ±1°C of the optimum temperature, the heating capacity of the second heater 23 is set to 20 to 40% of the total heating capacity of the first heater 22 and the second heater 23.
It is desirable to set it in the range of %. If each heater is designed within this range, even if the outside temperature fluctuates widely, highly accurate temperature control can be easily achieved with an economical control device, such as a simple on/off control device.

In addition, the heating capacity and necessary number of heaters, the optimum temperature for temperature control, etc. of each heater are optimally determined by the outside temperature conditions, the dimensions and materials of the neck and stem of the cathode ray tube. It is not limited to numerical values.

[Effects of the Invention] According to the present invention, the first heater is installed inside the mount pin on which the stem structure is attached, and the second heater is installed around the outer periphery of the mount pin, so that the mount pin The part of the mount pin that comes into direct contact with the outside air is reduced, and the temperature of the mount pin base is less affected by the outside air temperature.

Further, since this reduces the variation in the heating load of the heater mounted in the mount pin, the temperature of the mount pin base can be controlled with high precision.

Therefore, the temperature of the mount pin cap is always maintained with high precision, and the stem of the stem structure mounted on the tube can be maintained at the optimum temperature, thereby ensuring welding between the stem structure and the neck of the cathode ray tube. It can be done with high precision.

[Brief explanation of the drawing]

FIG. 1 shows an embodiment of the mount pin according to the cathode ray tube sealing device of the present invention, +a+ is a longitudinal cross-sectional view, (1) is a cross-sectional view on the line A-A of +a+, and FIGS. 2 and 3 4 is an explanatory diagram of a cathode ray tube sealing device, FIG. 5 is a conventional example of a cathode ray tube sealing device, ta) is a longitudinal sectional view, (bl is ta) FIG. 20...Mount pin, 21...Mount pin base, crimp M hkfu M Fig. 5 yp&+ item Introduction - item Fig. 4

Claims (1)

[Scope of Claims] 1. The stem structure is installed in a culletless cathode ray tube sealing device that heats and welds both the open end of the neck of the cathode ray tube bulb and the stem structure on which the electron gun structure is mounted. 1. A sealing device for a cathode ray tube, comprising: a first heater mounted inside a mount pin; and a second heater mounted outside the mount pin. 2. The first heater controls its heating capacity in response to the temperature of the mount pin base provided at the top of the mount pin to keep the temperature of the mount pin base constant. The cathode ray tube sealing device according to item 1.