JPH0752629B2 - Magnetic shield mounting structure - Google Patents

Description

TECHNICAL FIELD The present invention relates to a mounting structure of an internal magnetic shield in a color cathode ray tube.

[Conventional technology]

In a conventional color picture tube, a magnetic shield is housed in the tube in order to shield an external magnetic field such as the earth's magnetism, and this magnetic shield is attached to a frame holding a shadow mask. As such a conventional mounting structure,
53-16275 and Japanese Utility Model Laid-Open No. 54-125573 are disclosed, and their outlines are shown in FIGS. 2 to 4. In the figure, reference numeral 1 denotes a panel, the open end surface of which is welded to the tip of the funnel 8 by frit glass or the like. Reference numeral 2 is a support pin provided on a side wall of the panel 1, 3 is a shed mask, 4 is a frame, and this frame 4 is a skirt portion 4a to which the shed mask 3 is fixed, and is bent inward in a frame shape to the skirt portion 4a. A plurality of engaging holes 4c (second flange 4b at predetermined intervals).
(See the figure). Reference numeral 5 denotes a support elastic body having one end fixed to the frame 4 and the other end fitted to the support pin 2 through an opening. An internal magnetic shield having a bottom free end 6a and arranged so as to cover the traveling path of the electron beam. 7 is this magnetic shield 6
Spring for fixing the to the frame 4 4-5mm
The leaf spring material is bent into a V shape as shown in FIG. Then, the spring 7 as described above is compressed at both ends 7b as shown by arrows so that the magnetic shield 6 and the frame 4 are provided with locking holes.
After inserting into 6b and 4c and locking the intermediate recess 7a to both,
The three members are fixed together by releasing the pressing force.

[Problems to be solved by the invention]

However, in such a mounting structure, as shown in FIG. 2, the arrangement of the locking holes 4c on one side of the frame 4 is a coaxial line (AA) parallel to the vertical axis (YY) of the color CRT. ), The bottom surface where the inner magnetic shield 6 and the frame 4 contact each other is located on the coaxial line (AA) with respect to the locking hole 4c via the spring 7. Here, the coaxial wire (AA) is located near the skirt portion 4a of the frame 4, and when the flange portion 4b of the frame 4 is long, the bottom surface of the inner magnetic shield 6 is made flat even in terms of manufacturing accuracy. This is extremely difficult and has a curved bottom shape, so that a gap is created between the flange portion 4b and the free end 6a of the bottom surface of the inner magnetic shield 6. For example, when a color picture tube is incorporated in a television set and used, this void may cause resonance due to external impact or vibration due to the sound frequency of the external speaker, etc. Generate. In addition, a degaussing coil is attached to the outer circumference of the color CRT in order to prevent deterioration of color purity due to magnetization of magnetic materials such as the shadow mask 3, the frame 4 and the internal magnetic shield 6 in the color CRT due to the influence of the earth's magnetism. Even when an electric current flows through the degaussing coil, the magnetic body resonates, and the metallic vibrating sound as described above is generated on the bottom surface of the internal magnetic shield 6. The flange 4b of the frame 4 is preferably long in order to increase the rigidity, which promotes the above defects. Even if the coaxial line (AA) is located away from the skirt portion 4a of the frame 4, the coaxial line (A-A) still has the defect.

This invention has been made to solve the above drawbacks, and by changing the arrangement of the locking holes of the frame,
(EN) A magnetic shield mounting structure capable of maintaining a stable contact state between a frame and an internal magnetic shield.

[Means for solving problems]

The magnetic shield mounting structure according to the present invention is such that at least one of the locking holes having at least three positions on one side of the frame for locking the inner magnetic shield to the frame by the spring is provided on the frame more than other positions. It is arranged so as to be displaced on coaxial lines different in the longitudinal direction.

[Action]

According to the present invention, at least one of the locking holes of the spring is positioned so as to be displaced on different coaxial lines in the longitudinal direction of the frame. Therefore, even if the bottom surface of the magnetic shield is not uniformly flat, It is possible to prevent the generation of metallic vibration noise due to vibration.

〔Example〕

FIG. 1 is a view showing an arrangement state of locking holes of a frame which is an embodiment of the present invention. That is, at least one or more of the locking holes 4c on at least three coaxial lines (BB) provided on the flange portion 4b of the frame 4 parallel to the vertical axis (Y-Y) of the frame 4 The locking hole 4c is provided on a coaxial line (C-C) having different longitudinal directions in the vertical axis (Y-Y) direction of the frame 4. When fixing the inner magnetic shield 6 to the locking hole 4c arranged in this way, even if the bottom surface of the inner magnetic shield 6 is not uniformly flat, the coaxial line (BB) and the coaxial line (C) −
The free end 6a of the bottom surface of the inner magnetic shield 6 is pressed by the elastic locking of the spring 7 between C). Therefore, the metallic vibrating sound due to the above-mentioned vibration is not emitted. The coaxial line of the locking hole 4c is the vertical axis of the frame 4 (Y-
The closer to Y), and the number of locking holes 4c is at least three, the higher the effect is.

〔The invention's effect〕

As described above, according to the present invention, among at least three locking holes for fixing the inner magnetic shield to the frame by the spring, at least one position is displaced in the vertical axis direction of the frame, and thereby, It is possible to maintain a stable contact state between the frame and the internal magnetic shield, and the effect of preventing an abnormal phenomenon such as generation of metallic vibration noise due to resonance is remarkable.

[Brief description of drawings]

1 is a plan view showing an embodiment of the present invention, FIG. 2 is a plan view showing a conventional example, FIG. 3 is a schematic view showing a mounting structure of an internal magnetic shield, and FIG. 4 is a perspective view showing a spring shape. Is. In the figure, 4 is a frame, 4c is a locking hole, 6 is an internal magnetic shield, 6a is a free end, and 7 is a spring. The same reference numerals in the drawings indicate the same or corresponding parts.

Claims (1)

[Claims] 1. A shadow mask having a large number of pores, a frame-shaped frame that supports the shadow mask, a magnetic shield that is attached to the frame and covers a traveling path of an electron beam, and fits into the holes of the frame and the magnetic shield. Inserted,
In the one provided with a plate-like spring for fixing the magnetic shield to the frame, there are at least three fixing positions of the spring on one side of the frame, and at least one of the fixing positions on the one side.
A magnetic shield mounting structure in which a position is displaced from another fixed position on a different coaxial line in the longitudinal direction of the frame.