JPH027139B2 - - Google Patents

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to a getter flash method for cathode ray tubes in which a getter agent is vapor-deposited on the inner surface of a tube body. It relates to a method for preventing body fatigue.

[Prior Art] Generally, for example, in a television picture tube, the inside of the tube is maintained at a high vacuum for a long period of time.
In addition, in order to maintain good electron emission from the cathode, a getter container filled with a getter agent is installed inside the tube, and during the exhaust process, the getter agent is scattered by high-frequency heating to form a getter film.

Conventionally, this type of getter flush method has been used, for example, as disclosed in JP-A-59-12551, in which a getter device is made asymmetric by providing a high portion and a low portion on the outer wall of the getter container. In order to prevent the getter metal released from the getter device from adhering to the vicinity of the electron gun, and to evenly heat the asymmetric getter device, the induction coil for the getter flash was designed to be connected to the main coil. It is known that it is formed asymmetrically.

A high frequency generator is connected to the above induction coil,
For example, a high frequency current with a frequency of 100 KHz to 1000 KHz, preferably 200 KHz to 500 KHz is applied to perform high frequency heating of the getter agent. This high-frequency heated getter agent scatters as metal vapor and is deposited on the inner surface of the tube.

[Problems to be Solved by the Invention] However, according to the configuration of the Getter container,
In order to prevent getter metal from adhering to the vicinity of the electron gun, it is necessary to construct the outer wall of the getter device asymmetrically between a high part and a low part, which has the disadvantage that getter metal scatters from the low part onto the phosphor screen. There is.

Further, by configuring the outer wall of the getter device asymmetrically between a high portion and a low portion, the coil must also be formed asymmetrically. In other words, in order to evenly heat the high and low parts of the outer wall of the Getter device, the high and low parts are heated with a high circumference by the main coil, and the high part is auxiliary heated with a small sub-coil. There must be.

Moreover, even when the sub-coil is used to supplementally heat the high area as described above, there is a risk that the metal vapor of the getter agent will condense on the high area and the getter metal will fall, causing a short circuit between the electrodes of the electron gun. be.

If you want to definitely prevent this, the above coil
A situation arises in which a relatively high high frequency current of 400 KHz or more must be applied to perform high frequency heating of the getter agent.

While Getter Flash is being performed,
When a relatively high high-frequency current is applied, a potential difference is generated between the getter device and its vicinity due to high-frequency heating, causing creeping discharge, which causes cracks on the glass surface of the tube that the getter device is in contact with. . Furthermore, when creeping discharge occurs over a long period of time, the tube body may be completely damaged.

The present invention has been made in order to eliminate the above-mentioned drawbacks, and an object of the present invention is to provide a getter flash method for a cathode ray tube that can prevent the getter agent from adhering to the phosphor screen and can effectively prevent damage to the tube body. purpose.

[Means for Solving the Problems] The present invention has a symmetrical structure having a getter container filled with a getter agent, and a getter shield having a brim shape on the opening side of the getter container and expanding toward the inside of the tube body. The device is equipped with a getter device and is characterized in that it conducts high-frequency heating of the getter agent by passing a high-frequency current of 200KHz to 350KHz through the getter flash coil.

[Function] According to the above method, a getter shield is used which is spread out in a shape toward the inside of the tube on the opening side of the getter container. The getter agent is reflected toward the inner surface of the tube in the vicinity of the getter device during the getter flash, and is deposited on the inner surface of the tube in the vicinity of the getter device.

This allows the getter agent to be vapor-deposited on the phosphor screen formed on the inner surface of the panel, thereby preventing a decrease in brightness and uneven brightness.
This prevents the metal vapor of the getter agent from scattering toward the electron gun, thereby preventing short-circuit accidents between the electrodes of the electron gun.

Moreover, since a relatively low high-frequency current of 200KHz to 350KHz is applied to the getter flash coil to perform high-frequency heating of the getter agent, there is a potential difference between the getter device and its vicinity due to the high-frequency heating. Even if this occurs, the potential difference can be suppressed to a relatively low level, so there is no risk of creeping discharge occurring.

Furthermore, even if the above-mentioned creeping discharge occurs, the amount of current flowing through the creeping discharge can be suppressed as much as possible compared to the conventional method, so that cracks can be prevented from occurring on the glass surface of the tube that the getter device comes into contact with. Can be done. This is true even when creeping discharge occurs for a long time.

[Example] Hereinafter, an example of the present invention will be described with reference to the drawings.

Figure 1 shows an outline of a cathode ray tube. A support piece 3 is attached to the electron gun 2 set in the neck portion 1a of the tube body 1, and the tip of the support piece 3 is connected to the internal conductive film 6 coated on the funnel portion 1b via a spring 5.
It is connected to the. At the tip of the support piece 3,
A getter device 4 is fixedly supported.

Details of the getter device 4 are shown in FIG. In this figure, a getter container 4a is filled with a getter agent 4b. Reference numeral 7 denotes a getter flash coil. A high frequency generator (not shown) is connected to this coil 7, and a high frequency current of 200 KHz to 350 KHz is applied.

By this energization, the getter device 4 that is close to the coil 7 is heated by high frequency from outside the tube body 1. When, for example, 5 to 10 seconds have elapsed after the start of this high-frequency heating, the temperature of the getter device 4 rises to approximately 900°C to 1000°C. The getter agent 4b of the getter device 4 heated by high frequency scatters as metal vapor and is deposited on the inner surface of the tube body 1.

At this time, the getter agent 4b is reflected by the getter shield 4c in the direction of arrow A,
It is deposited between the spring 5 of the support piece 3 and the getter film 10. In other words, a large amount of the getter agent 4b is scattered particularly on the side of the funnel portion 1b where the getter device 4 is mounted, and the getter film 10 is formed.

As a result, the getter film 10 is vapor-deposited on the phosphor screen 9 formed on the inner surface of the panel 8, thereby making it possible to prevent a decrease in brightness and the occurrence of uneven brightness. By preventing the electrons from scattering to the electron gun 2 side, short circuit accidents between the electrodes of the electron gun 2 can be prevented.

Moreover, since a relatively low high frequency current of 200KHz to 350KHz is applied to the getter flash coil 7 to perform high frequency heating of the getter film 10, the getter device 4 and its vicinity 1
Even if a potential difference occurs between the two and the two due to high frequency heating, the potential difference can be suppressed to a relatively low level, so there is no risk of creeping discharge occurring.

Furthermore, even if the above-mentioned creeping discharge occurs, the frequency of the high-frequency current is set at 200KHz to 350KHz, which is lower than the conventional case where a relatively high high-frequency current of 400KHz or more is applied. , the amount of current flowing through the creeping discharge can be suppressed as much as possible.

Therefore, it is possible to prevent cracks 11 from forming on the glass surface of the tube body 1 with which the getter device 4 comes into contact, and the same effect can be achieved even when creeping discharge occurs for a long time. .

[Effects of the Invention] As described above, according to the present invention, a getter container filled with a getter agent and a getter shield that is in the shape of a collar when expanded toward the inside of the tube on the open side of the getter container are provided. Equipped with a Getter device with a symmetrical structure, the getter flash coil has a 200K
Since the getter agent is heated at high frequency by passing a high frequency current of Hz to 350 KHz, it is possible to prevent the getter agent from adhering to the phosphor screen and to effectively prevent damage to the tube body.

[Brief explanation of drawings]

Figure 1 is a vertical cross-sectional view showing an example of a cathode ray tube;
The figure is a longitudinal sectional view showing details of the getter device. 1...Tube body, 2...Electron gun, 3...Support piece, 4
...Getter device, 4a...Getter container, 4b
...Getter agent, 4c...Getter shield, 6
...Inner conductive film, 7... Coil, 10... Getter film. In addition, in the figures, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] 1. A getter container filled with a getter agent, which is supported by an electron gun support piece connected to the internal conductive film of the tube, and a brim-shaped getter shield that expands toward the inside of the tube on the open side of the getter container. A getter device having a symmetrical structure having A getter flash method for a cathode ray tube in which a getter film is formed by reflecting a getter film onto an internal conductive film by the getter shield, characterized in that the frequency of the high-frequency current is set at 200 KHz to 350 KHz. Cathode ray tube getter flash method.