JPS5811067B2 - color picture tube - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a color picture tube in which a funnel-shaped magnetic shield is provided within a face panel portion.

Conventionally, in order to avoid the influence of so-called external magnetic fields such as terrestrial magnetism, a funnel-shaped magnetic shield made of steel, for example, has been provided within the funnel portion of the color picture tube envelope.

However, when such a magnetic shield is attached to the mask frame of a shadow mask, its load tends to cause thermal deformation to the mask frame or shadow mask during tube evacuation or heating of electrodes in the aging process or during tube operation.

In addition, vibrations during transportation of the tube are likely to damage the mask frame, especially the support portion.

The present invention provides a color picture tube that eliminates the conventional drawbacks as described above.
A description will be given below along with embodiments shown in the drawings.

In FIG. 1, a glass envelope 1 is a phosphor screen 2.
, a face panel part 5 enclosing a shadow mask 3 and a mask frame 4, a funnel part 7 enclosing a funnel-shaped magnetic shield 6, and a neck part 9 enclosing an electron gun 8.
and a stem portion 10, and the shadow mask 3 is a second
As shown in the figure, one opening of a steel frame-shaped mask frame 4 is covered.

Further, the mask frame 4 integrally has a tubular frame edge portion 11 protruding toward the tube axis on the other opening edge, that is, on the opening edge on the side opposite to the side where the shadow mask is attached. , is removably attached within the face panel 5 by three or four leaf springs 12 provided on the side wall.

On the other hand, the funnel-shaped magnetic shield 6 made of a thin steel plate is
It is detachably attached within the funnel portion 7 by an appropriate number of leaf springs 13 provided on its outer surface.

That is, by fitting the hole 15 of the leaf spring 13 into the convex protrusion 14 provided on the inner circumferential surface of the funnel part 7, the effect of legally supporting the magnetic shield 6 with respect to the funnel part 7 is obtained. .

Note that the protrusion 14 is a glass or metal pin formed when the funnel portion 7 is molded.

The magnetic shield 6 integrally has an annular frame edge portion 16 protruding toward the tube axis at the opening edge of its large diameter portion, and this frame edge portion 16 is adjacent to the frame edge portion 11 of the mask frame 4. And they are facing in parallel.

The frame edge portion 16 not only effectively reinforces the magnetic shield 6, which is at most 0.1 mm to 0.2 mm thick, but also allows the overscanned electron beam to be directed toward the screen 2 by appropriately setting its protrusion length. It serves as a so-called electron shield to eliminate the risk of electrons entering the body.

The magnetic shield 6 is connected to the conductive film 1 on the inner surface of the funnel portion 7 through the leaf spring 13 or a dedicated tongue-shaped conductive piece.
However, as shown in FIG. 3, the anode terminal lead-out button 18 sealed to the funnel part 7 is integrally provided with a protrusion 19 corresponding to one of the protrusions 14. In this case, the magnetic shield 6 will be held at an anode potential through the protrusion 19.

Incidentally, a magnetic metal ring 20 made of steel or other material is attached to the mask frame 4 so as to substantially surround the mutual gap between the mask frame 4 and the magnetic shield 6 without contacting the magnetic shield 6.

For this reason, the mask frame 4 and the magnetic shield 6 are closely coupled magnetically even though they are separate bodies, due to the fact that their frame edge portions 11 and 16 are close to each other and face each other, resulting in a good magnetic shielding effect and A demagnetizing effect can be obtained.

Note that the magnetic metal ring body 20 may be provided on the magnetic shield 6 side as shown in FIG.

As described above, in the color picture tube of the present invention, the mask frame 4 is attached to the face panel section 4, the magnetic shield 6 is attached to the funnel section 7, and the opening edge of the mask frame 4 on the side opposite to the mask and the magnetic shield are attached. 6
The frame edge portions 11 and 16 protruding toward the tube axis, which are respectively provided at the opening edges of the large diameter portion, are brought close to and opposite each other, and the opening edge on the anti-mask side and the opening edge of the large diameter portion A magnetic metal ring that substantially surrounds the gap between the edges of both openings without contacting the other is provided on one of the two, and then the mask frame 4 and the shadow mask 3 are deformed by the load of the magnetic shield 6. Moreover, the magnetic shield 6 and the mask frame 4 are closely magnetically coupled, and good magnetic shielding and demagnetizing effects can be obtained.

Furthermore, the magnetic shield 6 is not only stably supported independently of the mask frame 4, but also has the excellent effect of preventing secondary electrons from entering from the inner surface of the glass envelope to the inner surface of the shadow mask.

[Brief explanation of drawings]

FIG. 1 is a partially cutaway side view of a color picture tube embodying the present invention, FIG. 2 is a perspective view of essential parts of the same color picture tube, and FIGS. 3 and 4 are views of other embodiments of the present invention. FIG. 1...Glass envelope, 3...Uyadou mask, 4...Mask frame, 5...
Face panel section, 6...Magnetic shield, 7.
... Funnel part, 11°16 ... Frame edge part, 20 ... Magnetic metal ring body.

Claims (1)

[Claims] 1. A picture frame-shaped mask frame attached to the face panel portion of the glass envelope has a frame edge portion protruding toward the tube axis at the opening edge on the side opposite to the side on which the shadow mask is attached, and A funnel-shaped magnetic shield installed in the funnel portion of the envelope has a frame edge portion close to and opposite the frame edge portion at the opening edge of the large diameter portion thereof, and the opening edge on the opposite side and a color picture tube, characterized in that either one of the opening edges of the large diameter portion has a magnetic metal ring that substantially surrounds the gap between both opening edges without contacting the other.