JP2947883B2 - Getter flash method for electron tube - Google Patents

Description

Description: Object of the Invention (Industrial Application Field) The present invention relates to a getter flash method for an electron tube such as a cathode ray tube, and in particular, a getter member arranged inside the tube of an electron tube is arranged outside the tube. The present invention relates to a getter flash method for an electron tube in which a getter is flashed by heating with a high-frequency heating coil.

(Prior Art) In general, in order to increase the degree of vacuum after evacuation and maintain the degree of vacuum for a long period of time to maintain predetermined characteristics, a getter member is disposed together with various inner tube members in an envelope. It is known.

As such a getter member, for example, in a color picture tube, a flash getter is used. That is, in a color picture tube, as shown in FIG. 2, a getter member (1) is provided with an electron gun (4) disposed in a neck (3) of a funnel-shaped funnel (2) constituting an envelope. The getter support (5) is mounted on the front end of the funnel (2) and disposed inside the cone (6) of the funnel (2). The reason for disposing the getter member (1) inside the cone portion (6) in this manner is to apply a flashed getter to a wide area in the tube to effectively exert the getter function as described later. .

The getter member (1) arranged inside the cone portion (6) of the funnel (2) faces the getter member (1) after exhausting the tube in the manufacturing process of the color picture tube, and outputs a high-frequency wave outside the tube. A heating coil (8) is arranged, a high-frequency current is passed through the high-frequency heating coil (8) for a predetermined time to induce an induced current in the getter member (1), and the getter is heated by the induced current to flash the getter. The flashed getter faces the phosphor screen composed of the three-color phosphor layer on the inner surface of the panel integrally joined to the funnel (2), and is disposed inside the shadow mask and the cone portion (6) of the funnel (2). It is applied in a thin film over a wide area on the inner conductive film coated on the inner surface, etc., adsorbs residual gas in the exhausted tube, increases the degree of vacuum, and emits harmful gases released during operation of the color picture tube By adsorbing the gas in the tube, the degree of vacuum is maintained for a long time to maintain predetermined characteristics.

Usually, a getter member (1) comprising such a flash getter is provided with a thin film of barium-aluminum alloy and nickel powder in an annular groove of a support ring (10) having a U-shaped cross section as shown in FIG. It is formed into a structure filled with the mixture (11), and when it is heated to about 900 ° C., the barium is flashed by self-heating.

Regarding such a getter member (1), the relationship between the flash start time and the flash barium amount when a constant high-frequency current is passed through the high-frequency heating coil and heated is shown in the fourth section.
This is shown by the curve (13) in the figure. The actual flash conditions in the tube production are as follows: Use a dummy tube, position and fix the high-frequency heating coil, measure the flash start time when high-frequency current is applied, and measure the high-frequency current and current so that the appropriate flash amount can be obtained. The high-frequency heating coil (10) is positioned and fixed in the same relationship as the dummy tube with respect to the color picture tube after the evacuation by setting the time and the high-frequency current and energizing time. The high-frequency current is constant throughout as shown by a broken line (14) in FIG. 1. With this constant high-frequency current, the getter member (1) starts flashing between t1 and t2 and ends flashing at t3. I do.

(Problems to be Solved by the Invention) As described above, in general, an electron tube has been conventionally provided with a vacuum inside the envelope in order to increase the degree of vacuum after evacuation and maintain the degree of vacuum for a long period of time to maintain predetermined characteristics. A getter member is arranged together with various in-pipe members. As a getter member, a flash getter is used in a color picture tube, which is arranged inside a cone portion of a funnel-shaped funnel constituting an envelope, and after exhausting the tube, facing the getter member,
A high-frequency heating coil is positioned and fixed outside the tube, and a constant high-frequency current is supplied to the high-frequency heating coil for a predetermined time to heat and flash.

However, in the above getter flash method, a constant high-frequency current is passed through the high-frequency heating coil for a predetermined time due to a relative displacement between the getter member disposed inside the cone portion and the high-frequency heating coil positioned and fixed outside the tube. Also, the heating of the getter member is weakened, and the flash start timing is delayed, so that an appropriate flash amount may not be obtained.
That is, in the conventional getter flash method, the flash amount is not stable, the pipe characteristics are deteriorated, and the reliability may be impaired.

The present invention has been made in order to solve the above problems, and in a getter flash method of flashing a getter by heating a getter member arranged in a tube of an electron tube by a high-frequency heating coil arranged outside the tube. It is another object of the present invention to provide a getter flush method for accurately and stably flushing a getter.

[Constitution of the Invention] (Means for Solving the Problems) Induction is caused in the getter member by flowing a high-frequency current to a high-frequency heating coil disposed outside the tube opposite to the getter member disposed inside the electron tube for a predetermined time. In the getter flash method for an electron tube in which a getter is flashed by heating by an induced current, the magnitude of a high-frequency current flowing through the high-frequency heating coil before the getter starts flashing is set to 100%, and the high-frequency A high frequency current of 105-120% was passed through the heating coil to flash the getter.

(Operation) As described above, the magnitude of the high-frequency current flowing through the high-frequency heating coil until the getter starts flashing,
If a high-frequency current of 105 to 120% is applied after the start of the flash, for example, the getter member and the high-frequency heating coil are relatively displaced, and the heating of the getter member is weakened. By increasing the current after the start of the flash, the heating of the getter member is increased, so that the flash amount can be increased and an appropriate flash can be performed within a predetermined time.

Hereinafter, the present invention will be described based on embodiments with reference to the drawings.

FIG. 1 is a view for explaining a getter flash method for a color picture tube as one embodiment. Normally, a color picture tube has a phosphor screen (21) formed of a three-color phosphor layer in the form of dots or stripes formed on the inner surface of a panel (20), and a number of electron beam passage holes are formed inside the panel (20). Attach the formed shadow mask (22). on the other hand,
An inner dielectric film (23) containing carbon as a main component is applied and formed on the inner surface of the funnel (2). Then, the funnel (2) on which the inner conductive film (23) is formed and the fluorescent screen (2) are formed.
1) is formed and joined together with the panel (20) on which the shadow mask (22) is mounted. Next, the electron gun (4) with the getter member (1) attached thereto is sealed in the neck (3) of the integrally joined funnel (2) via the getter support (5), and the getter member (1) is sealed. ) Is disposed on the inner conductive film (23) applied to the inner surface of the cone (6) of the funnel (2). Next, the sealed tube of the electron gun (6) is evacuated, and then the tube is opposed to the getter member (1) located on the inner conductive film (23) on the inner surface of the cone portion (3). A high-frequency heating coil (25) is provided, a high-frequency current is supplied to the high-frequency heating coil (25) for a predetermined time, and the getter member (1) is heated by an induction current induced in the getter member (1) by the high-frequency current. Flash the getter.

In the conventional getter flash method, the high-frequency current flowing through the high-frequency heating coil was constant throughout as described above. However, in the getter flash method of this embodiment, as shown by a solid line (27) in FIG. Heating coil (2
5) A high-frequency current of a certain magnitude is applied from the start of energization (start of heating of the getter member) to the start of the getter flash, and after the start of the getter flash, when the magnitude of the current to flow until the start of the getter flash is 100, 1
The getter is flushed by passing a high-frequency current of a magnitude of 05 to 120% (110% in FIG. 2).

The magnitude and energizing time of the high-frequency current flowing through the high-frequency heating coil are determined so that most getters flash within a predetermined time. For example, when the energization time is 20 seconds, the magnitude of the high-frequency current is set so that the getter flash starts approximately 9 seconds after the energization starts.

As described above, the high-frequency current flowing through the high-frequency heating coil (25) is changed from the current flowing before the start of the getter flash by the start
When a current of 5 to 120% is applied, for example, a getter member (1)
In contrast, even if the high-frequency heating coil (25) is displaced relatively and the heating of the getter member (1) weakens, the heating increases after the start of the getter flash to increase the heating and correct the decrease in the flash amount. By supplying a high-frequency current for a predetermined period of time, an appropriate amount of flash can always be stably performed.

In Table 1, the start time of the getter flash is set to 9 seconds after the start of energization, and the flash amount when the current after the start is set to 110% or 120% with respect to the current flowing before the start of the getter flash is compared with the conventional fixed high frequency. This is shown in comparison with the case where a current is applied (Comparative Example).

As can be seen from the results in Table 1, when the current after the start of the getter flash is increased, the variation in the flash amount is smaller than in the conventional getter flash method,
Also, a large amount of getter can be flashed within the same time. If the current after the start is lower than 105% of the current flowing before the start of the getter flash, the effect of increasing the current is not sufficiently exhibited, and the variation of the flash amount becomes large. Also, if the current after the start of the getter flash is higher than 120%, the residue after the flash and the melting of the getter member (1) are likely to occur, and the magnitude of the current flowing after the start of the getter flash is as follows. Assuming that the previous current is 100%,
120% is optimal.

Although the getter flash method for a color picture tube has been described above, the present invention can be applied to a getter flash method for an electron tube other than the color picture tube.

[Effects of the Invention] When a high-frequency current is passed through a high-frequency heating coil disposed outside the tube opposite to a getter member disposed inside the electron tube for a predetermined time, the getter member is heated to flash the getter. If the current flowing through the high-frequency heating coil after the start of flashing is 105 to 120% of the magnitude of the high-frequency current flowing through the high-frequency heating coil before the start of flashing, the variation in the flash amount due to the increase in current after the start of flashing It is possible to reduce the number of the getters, and to perform a stable getter flush, so that an appropriate amount of the getter can be flushed within a predetermined time. In addition, since the flash amount increases, the energizing time of the high-frequency heating coil, that is, the time required for getter flash can be reduced, and the productivity of the electron tube can be improved.

[Brief description of the drawings]

FIG. 1 is a view for explaining a getter flash method for a color picture tube according to an embodiment of the present invention, and FIG. 2 compares a high-frequency current flowing through the high-frequency heating coil with a high-frequency current in a conventional getter flash method. FIG. 3 is a view for explaining a conventional getter flash method for a color picture tube, and FIGS. 4 (a) and 4 (b) are a plan view showing the structure of the getter member and its IV-IV line, respectively. FIG. 5 is a sectional view showing the relationship between the flash start timing and the flash amount. 1 ... getter member, 2 ... funnel, 5 ... getter support, 25 ... high frequency heating coil.

Claims (1)

(57) [Claims] 1. A high-frequency current is passed through a high-frequency heating coil disposed outside a tube opposite to a getter member disposed in a tube of an electron tube for a predetermined time, thereby heating the getter by an induced current induced in the getter member. At the time of flashing, the magnitude of the high-frequency current flowing through the high-frequency heating coil before the getter starts flashing is set to 100%, and the high-frequency heating coil is supplied to the high-frequency heating coil after the start of flashing.
A getter flash method for an electron tube, characterized by flowing a high frequency current of 105 to 120% to flash a getter.