JPH0268843A - Color cathod-ray tube - Google Patents

Abstract

PURPOSE:To make it possible to maintain electron emission characteristics favorable for a long period by arranging a flash getter toward the outside of an inner lead near the inside of a funnel, between the inside of the funnel and the outside of the inner shield. CONSTITUTION:A getter 2 is arranged in the space caught between the outside of an inner shield 5 and the inside of a funnel 6. For the mounting position in getter assembly, if the height of the inner shield 5 is defined as h, with the length of a getter supporting spring (the part that it becomes almost parallel with the inside of the funnel) as 1/3-2/3h, getter films are attached to the outside of the inner shield and the inside of the funnel opposed to the inner shield. Hereby, even if a color cathode-ray tube that the inner shield is oversize, it becomes possible to absorb gas discharged into the tube speedily at any time, and as a result, it maintains electron emitting characteristics favorable for a long period.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides a color cathode ray tube that is equipped with a relatively large inner shield inside the funnel, and when the flash getter is flashed, even if the inner shield is present. Regardless, the getter film coating surface was formed over a relatively wide area. The present invention relates to a color cathode ray tube that has a high ability to absorb gas released into the tube after the seal is cut.

[Prior Art] Color cathode ray tubes generally have a large internal bulb volume, and
The bulb is equipped with a member that easily releases so-called gas when impacted by the high-speed electron beam.

Therefore, for the gas released into the pipe after the seal is cut,
Various countermeasures have been taken in the past. For example,
Publication No. 1-48554 discloses that a getter scattering gas source device is provided to emit a type of gas such as N2 that does not have a negative effect on the electron emission function of the cathode, and to create a trajectory in which the getter is scattered when the getter is flashed. It has been disclosed that a getter film can be formed even in places that cannot be reached by a straight trajectory by scattering the getter film. However, even if the electron emission function of the cathode does not deteriorate, it is undesirable for the gas pressure inside the tube to become high. Diffraction of the getter vapor by flashing the getter in an atmosphere has been described, but as with the technique above, this type of method actually produces undesirable side effects when trying to obtain its full effect. .

[Problem to be solved by the invention] In recent years, with the pressure to improve the performance of color cathode ray tubes,
The magnetic shielding inner shield placed inside the valve has become relatively large. This relatively large inner shield gets in the way, and the scattering range of the flash getter is limited to a relatively narrow area. Even if the amount of getter is increased, the area covered by the getter film formed inside the bulb does not increase. For example, the getter vapor does not scatter in the space sandwiched between the outer surface of the inner shield and the inner surface of the funnel, and a large area remains without being coated with the getter film.

Therefore, immediately after the color cathode ray tube finishes exhausting, the getter cannot instantly absorb the large amount of gas that is ejected from the fluorescent surface and shadow mask by the electron beam from the electron gun, and the cathode of the electron gun A problem has arisen in that the emitted gas with a high concentration has an adverse effect on the electron emission performance of the cathode.

The present invention solves the above-mentioned conventional problems, expands the area of the getter film coating surface produced by flashing the flash getter, improves the gas absorption speed of the getter, and provides a collar that prevents the electron emission performance of the cathode from deteriorating. The purpose is to provide cathode ray tubes.

[Means for Solving the Problems] In order to achieve the above object, in the present invention, an elastic member is attached to the end of the fluorescent surface side of the electron gun, and is attached to the junction with the neck pipe of the valve funnel. In addition to the flash getter installed near the inside of the funnel and facing the inner space of the funnel, a new flash getter is installed between the inside of the funnel and the outside of the inner shield, close to the inside of the funnel and facing the outside of the inner shield. I decided to install a flash getter.

[Operation: Currently, barium getters are overwhelmingly used as flash getters. The gas released into the tube collides with the part on which the barium getter is deposited and reacts with it. For example, it is known that a reaction as shown in the following equation occurs on the surface of a barium getter film.

Ba+H,○→BaO+2(H) 3Ba+2GO-+BaCz+2BaOB a C2+
H, O-+B a O+ 2(CH)(cH)+3(H
) → CH4 Therefore, in order for the gas released into the tube to be absorbed by the barium getter quickly enough, the reaction area must be wide, that is, the barium getter film must be deposited over a wide range, and the ratio of the deposited barium must be It is important that the surface area is large and that it can continuously absorb the gas in the tube, but the latter is important because the amount of gas emitted by the electron beam gradually decreases with the operating time of the color cathode ray tube, and the gas that has reacted with barium is also important. Since barium gradually diffuses into the inside of the getter film, it can be handled by depositing an amount of barium in the tube that corresponds to the total amount of gas released. However, upon investigation by the present inventor, it was found that immediately after manufacturing a color cathode ray tube, when gas is being ejected from the phosphor surface etc. with an electron beam, the degree of vacuum inside the tube is temporarily lowered.

On the other hand, by increasing the barium deposition area according to the present invention, the gas ejected by the electron beam does not remain in the tube for a long time and is quickly captured by the barium film. The cause of temporary deterioration of the electron emission function of the device can be removed.

[Embodiment] Fig. 1 is a cross-sectional view taken along a plane including the tube axis of an embodiment of the present invention, and in the figure, 1 is a flash getter installed in a conventionally customary position, and 2 is a flash getter installed in a new position according to the present invention. 3 is the support frame of the shadow mask,
4 is a shadow mask, 5 is an inner shield, 6 is a funnel of a glass vacuum envelope, 12 is a contact spring, 13 is a panel of the glass vacuum envelope, and 14 is an electron gun.

In a conventional color cathode ray tube, there is usually only a flash getter 1 installed in a conventionally customary position, and the getter coating film by this getter is applied to the getter 1 on the electron gun side surface of the shadow mask 4 and the inner surface of the funnel 6. It was formed around the entire circumference of the conical part near the neck of the funnel. However, in large color cathode ray tubes, the height of the internal magnetic shield, that is, the inner shield 5, has been increased to increase the surface area as a countermeasure against the deterioration of purity due to the influence of earth's magnetic field. It became impossible to form a getter film. In particular, almost no getter can enter the space between the outer surface of the inner shield and the inner surface of the funnel, and even though the surface exposed in this space is quite wide, no getter film is formed, and the getter film is not formed. No getter film was formed on the inner surface of the funnel on the side. Therefore, in large color cathode ray tubes, by increasing the size of the inner shield.

This effectively narrowed the area where the getter film was formed, reducing the rate (capacity) of absorbing gas generated (emitted) within the tube, and as a result, the lifespan of the cathode ray tube was reduced. .

In order to deal with this situation, in the present invention, as shown in Fig. 1, the getter 2 is disposed in the space between the outer surface of the inner shield and the inner surface of the funnel, so that the area to which the getter film is deposited is greatly expanded. Ta.

In FIG. 2(a), the inner shield 5 is attached to the support frame 3 of the shadow mask 4 using the hole.

This is a view of the getter assembly of the getter 2 being fixed by the locking spring 7 at the same time as the inner shield 5 is installed, as seen from inside the inner shield toward the funnel.
FIG. 2(b) is a side view showing its attached state. Instead of doing the above, the getter assembly may be welded directly to the surface of the shadow mask support frame 3, as shown in FIG. 2(c).

Further, as shown in FIG. 2(d), the getter assembly may be fixed by being fitted into a pin provided on the inner surface of the skirt portion of the panel 13 of the glass vacuum envelope.

Below, the getter assembly and its installation will be explained in more detail.

The getter assembly is performed using Fransch getter 2. as shown in FIGS. 2(a) and 2(b). Controls the getter film deposition area, supports the flefter 8 and getter 2, and positions (heights) in the tube axis direction
A getter support spring 10 for fixing the getter, a crossbar 9 that prevents the getter heated to a high temperature by high-frequency induction heating from directly contacting the glass funnel and causing it to crack when flashing the getter, and a support frame for the shadow mask. 5 of the spring support plate 11 made of a plate thinner than the plate thickness of the getter support spring 1o in order to increase the reliability of the welding strength between the getter support spring 1o and the getter support spring 1o.
It is composed of parts. Although not shown, the funnel 6 of the glass vacuum envelope and the skirt portion of the panel 13 are present on the right side of FIG. 2(b).

When installing the getter assembly, set the height of the inner shield to h.
Then, the length of the getter support spring 10 (the part that is almost parallel to the inner surface of the funnel) is set to about 1/3 to 2/3 h, and the getter film is applied to the outer surface of the inner shield and the inner surface of the funnel facing the inner shield. to cover. The getter film of this specification has almost no effect on the resistivity of the high-resistance internal conductive film of the so-called soft flash bulb, which is intended to suppress spark current during discharge inside the bulb. Further, in the manufacturing process, the getter assembly is installed in a process before the panel part and the funnel part are welded, and before the inner shield 5 is installed.Then, the panel and the funnel are welded, and the electron gun 14 is supported. After sealing the stem in the neck tube and completing an evacuation process to evacuate the tube, getter 2 is flushed by high-frequency induction heating in the same way as getter 1. The getter film created in this way by getter 2 increases the ratio of the getter film to the inner surface area of the bulb, which was around 50% with the conventional getter 1 alone, to over 70% by additionally installing getter 2. I was able to do it. As a result, we were able to improve the life of the cathode ray tube by more than 5%.

In addition, the getter film according to the present invention does not adhere to the electron gun side surface of the shadow mask 4, so unlike the case where the getter 1 is simply increased and scattered in a large amount, the black film applied to the shadow mask 4 Since the heat radiation performance of the color cathode ray tube is not deteriorated, there is no worsening of color shift due to so-called doming caused by thermal engraving of the shadow mask due to an increase in heat load while the color cathode ray tube is in operation. Note that the number of getters 2 to be attached is not limited to one, but it is extremely effective to attach a plurality of getters, for example two, symmetrically with respect to the tube axis.

[Effects of the Invention] As explained above, according to the present invention, even a color cathode ray tube with an enlarged inner shield can quickly absorb gas released into the tube, and as a result, it can be used for a long period of time. A color cathode ray tube that can maintain good electron emission characteristics and has a long life can be obtained.

[Brief explanation of the drawing]

Fig. 1 is a sectional view taken along a plane including the tube axis of an embodiment of the present invention, and Fig. 2 (a) = (b), (c), and (d) illustrate the getter and its attachment method according to the present invention. This is a diagram. 1...Flash getter attached to a conventional conventional position, 2...Flash getter according to the present invention, 3...
- Shadow mask support frame, 4...Shadow mask, 5...Inner shield, 6...Funnel of glass vacuum envelope, 7...Latching spring, 8...Reflector, 9... cross par
10... Getter support spring, 11... Spring support plate, 12... Contact spring,
13...Glass vacuum enclosure (support) panel, 14.
...Electron gun. ! Ba)

Claims (1)

[Claims] 1. In a shadow mask type color cathode ray tube equipped with an inner shield, the funnel is attached to the end of the electron gun on the fluorescent surface side via an elastic member, and the funnel is attached to the inner part of the bulb funnel near the junction with the neck tube. A color cathode ray tube comprising: a flash getter disposed toward the inner space; and a flash getter disposed between the inner surface of the funnel and the outer surface of the inner shield near the inner surface of the funnel and toward the outer surface of the inner shield. .