JPS5811004Y2 - color cathode ray tube - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to a color cathode ray tube, particularly a color cathode ray tube having an electron shield.

Generally, a color cathode ray tube consists of a panel part 2 having a substantially rectangular shape with a fluorescent film 3 on its inner surface, and a funnel part having a substantially conical shape following this panel part, as shown in FIG. 4. Neck part 5 at the end following this funnel part
a shadow mask 6 for color selection disposed inside the panel close to the fluorescent film 3;
It consists of a magnetic shielding plate 7 following this shadow mask 6, and an electron gun 8 housed within the neck portion 5.

The magnetic shield plate 7 is for preventing unnecessary magnetism from adversely affecting the operation, and as shown in FIG. 6, and the other end opening located on the funnel part 4 side has a frame part 7a bent inward.

When a color cathode ray tube with this configuration is operated, an overdeflected electron beam 9 passes through the outside of the magnetic shield plate 7.
As shown in the figure, this may strike the inner wall of the panel section 2 or the funnel section 4 and be reflected, and enter the fluorescent film 3 from an unfavorable direction, causing it to emit light. This resulted in a decline in the quality on the screen.

Therefore, an electron beam blocking member, ie, an electron shield, for blocking such an over-deflected electron beam 9 is interposed between the outer wall of the shadow mask 6 or the magnetic shield plate 7 and the inner wall of the panel section 2 or the funnel section 4. It was common to do so.

However, although a metal plate is generally used as the electron shield, the shapes of the shadow mask 6, the outer wall of the magnetic shield plate 7, and the inner walls of the panel section 2 and funnel section 4 are usually complicated. Not only does the shape of the electron shield itself require considerable consideration, but if it comes into contact with the inner surface of the panel section 2 or funnel section 4 made of glass, the glass may be exposed to small particles or racks during the heating process during manufacturing. This may cause fatal defects, or the conductive material coated on the inner surfaces of the panel section 2 and funnel section 4 may peel off, causing defects in the fluorescent surface and malfunction of the electron gun. , In the end, obtaining an electron shield that does not cause these drawbacks depends on its shape, t7. The manufacturing process such as the shape and cleaning, as well as the installation method, are extremely troublesome and lead to an increase in the cost of the color cathode ray tube.

This idea was developed in light of the conventional circumstances, and it involves attaching an electron shield plate made of a thin metal plate to the end of the magnetic shield plate on the side of the funnel part, and molding it into the required shape by conforming to the shape of the inner wall of the funnel part. This is how it was done.

Examples of this invention will be described in detail below with reference to FIGS. 3 to 6.

FIG. 3 shows the shape of an electron shield according to one embodiment. The electron shield plate 10 according to this embodiment is made of aluminum foil with a thickness of about 0.02 mm, and has a shape corresponding to the inner wall shape of the funnel part 4. It has a rectangular outer edge 11 larger than this, and the magnetic shield plate 7
It has a so-called square ring shape with a rectangular inner edge 12 that is smaller than the shape of the forehead part 7a,
A notch 13 is made at each corner of the inner edge 12.

Therefore, the electron shield plate 1 having the above-described configuration
0, first align the inner edge 12 with the opening of the forehead 7a of the magnetic shield plate 7 as shown in FIG. As shown in FIG. This is done immediately before the step of joining the panel section 2 and the funnel section 4.

Therefore, in practice, the magnetic shield plate 7 as shown in FIG.
Since the funnel part 4 will cover the electron shield plate 10 attached to the forehead part 7a of the
The thin and soft aluminum foil material is pressed against the inner surface of the funnel portion 4 and is naturally bent and wrinkled, resulting in the funnel portion 4 being bent as shown in FIG.
It is shaped into a roughly trapezoidal cone shape that is smoothed along the inner wall of the tube, forming the intended electron shield.

Therefore, when using an electron shield configured in this way, it is only necessary to use a thin metal plate such as aluminum foil as the material of the electron shield plate and form it into a simple shape, so it is easy to prepare and easy to clean. All you have to do is wash the material thoroughly beforehand, and it is easy to attach it to the magnetic shield plate without the need for any tools.Furthermore, because the material is thin and soft, For example, even if the outer edge comes into contact with the inner wall of the panel or funnel, there is no risk of damaging the glass or peeling off the coated conductive material, and the overall process can be carried out easily and inexpensively.

Furthermore, the electron shield plates installed in this way may require insufficient manual operation when assembled.
Alternatively, the formation of wrinkles may create a gap between the outer edge and the inner wall surface of the funnel part, but in general, what is most necessary for this type of electron shield is the magnetic shield, as shown in Figure 1 above. This is for electrons passing close to the funnel side end of the plate, and over-deflected electron beams passing away from this end are extremely rare under normal operating conditions. For electron beams that are extremely over-deflected, after being reflected on the inner surface of the funnel part, they are absorbed by the shadow mask or the side of the magnetic shield plate, causing the fluorescent surface to emit light unnecessarily. This is rare and can be said to not be much of a problem.

Furthermore, in such a case, during the subsequent heating process when attaching the electron shield, the portion away from the magnetic shield plate tends to become further softened by this heating and adhere tightly to the inner surface of the funnel part due to its own weight, so there is no risk of this happening. becomes even smaller.

Note that the magnetic shield plate does not necessarily have a forehead part on the funnel part side as in the example, and its shape is not limited to a trapezoidal conical shape, but even in such a case, Even if there is, by forming a slight new curve or unevenness on the opening edge on the funnel side, the inner edge of the electron shield plate can be entangled with these with sufficient strength.

Furthermore, in view of the gist of this invention, it is preferable that the thickness of the thin aluminum plate used be within approximately Q, 95 mm.

Furthermore, we mentioned forming an inner edge in the material, but if the material is thin and light like this, there is no need to make it into a window shape.
Simply place the rectangular center over the funnel-side opening of the magnetic shielding plate, then cut the part contained within the opening into an X-shape with a knife, etc., and wrap the resulting tongue around the edge of the opening. In some cases, it is sufficient to simply let the material soak, which can further reduce costs. It can be pulled out and cut out for use, making it even more streamlined.

[Brief explanation of the drawing]

Figure 1 is a partially cutaway side view showing the outline of the configuration of a color cathode ray tube to which this invention is applied, Figure 2 is a perspective view of the shadow mask and magnetic shield plate, and Figure 3 is the electron beam used in this invention. A plan view showing an embodiment of the shield plate, FIGS. 4 and 5 are perspective views and a partially longitudinal side view showing the procedure for attaching an electron shield plate to a magnetic shield plate, and FIG. 6 is an electron shield according to this invention. FIG. 2 is a partially cutaway side view of a color cathode ray tube that has been subjected to the following steps. 1... Vacuum container, 2... Panel part, 3
..... Fluorescent film, 4 ..... Funnel part, 5
...Neck part, 6...Shadow mask, 7...Magnetic shield plate, 7a...Forehead part, 8...Electron gun, 9... Hyperdeflected electron beam, 10... Electron shield plate, 11... Outer edge, 12... Inner edge, 1
3...notch, 14...bending part.

Claims (1)

[Scope of utility model registration request] In a color cathode ray tube, the funnel portion of the magnetic shield plate is provided with a shadow mask disposed close to a fluorescent film within a panel portion, and a magnetic shield plate positioned within a funnel portion and having one end fixed to the shadow mask. The inner edge of an electron shield plate made of a thin aluminum plate with a thickness of Q, Q5 mm or less is attached to the periphery of the side opening, and the outer edge of the electron shield plate is brought into contact with and runs along the inner surface of the funnel part. color cathode ray tube.