JPH0217902B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a mounting structure for a magnetic shield placed inside a color picture tube.

[Prior art]

Generally, the fluorescent surface of a color picture tube is manufactured by a photographic method using an optical system as follows.
This will be explained with reference to FIG. In Figure 1,
Panel 1 with the first color phosphor coated on the entire inner surface
A shadow mask 2 is attached to the exposure machine 3 and set at a predetermined position on the exposure machine 3. Next, the light source 4 installed at the bottom of the exposure machine 3 is moved to the positions 4R and 4 where the first color is printed.
Set it to either G or 4B and direct the irradiation light to optical system 5.
refract the electron beam to approximate the trajectory of the electron beam,
Color selection is performed using numerous electron beam passing holes 2H provided in the shadow mask 2, and the phosphor is burned. By developing the panel 1 on which the phosphor has been baked in this way, the baked phosphor portion remains. Next, the operations for the second and third colors are performed in the same manner as described above to complete the formation of the three-color phosphor layers. Therefore, the burning position of the phosphor is determined by the physical positional relationship between the panel 1, the shadow mask 2, and the light source 4.

FIG. 2 is a schematic diagram of a color picture tube. In this figure, a fluorescent screen 6 is formed on the inner surface of the panel 1 as described above. The panel 1 is joined to the funnel 7 and constitutes a part of the vacuum envelope 8. A shadow mask 2 faces the fluorescent screen 6, and a frame-like frame 9 to which the shadow mask 2 is fixed is supported by the skirt portion of the panel 1. Inside the neck of the vacuum envelope 8 is an electron gun 1 that emits three electron beams 10R, 10G, and 10B toward the fluorescent screen 6.
1 is built-in. One end of a magnetic shield 12 that partially or entirely surrounds the effective passage portion of the electron beam 10 inside the vacuum envelope 8 is attached to the frame 9 .

Electron beam 10 emitted from the electron gun 11
is color-selected by the electron beam passage hole 2H of the shadow mask 2, and collides with the selected phosphor of the fluorescent screen 6, causing that phosphor to emit light. If it is not present in a certain position, it will impair color purity,
This becomes a major defect in color picture tubes. Therefore, the electron beam passing hole 2 of the shadow mask 2
As a cause of shifting the position of H, distortion of the frame 9 to which the shadow mask 2 is welded and fixed can be mentioned. This will be explained in detail with reference to FIGS. 3 to 6.

FIG. 3 is a perspective view of a state in which the frame 9 and the magnetic shield body 12 are connected by four holders 13 made of metal plates. The connection structure is for each holder 1
The same is true for 3.

As shown in FIGS. 4a and 4b, a locking part 13a is provided at one end of one side of the holder 13, and a pressing protrusion 1 is provided near the other side.
3b are formed respectively.

Further, as shown in FIG. 5, a flange portion 12a is bent and formed at one end of the magnetic shielding body 12, and a tongue piece 12b formed by partially cutting out this flange portion 12a is provided in a protruding manner. 9
A rectangular hole 9b for the tongue piece 12b is formed in the flange portion 9a.

FIG. 6 is a cross-sectional view of the frame 9 to which the shadow mask 2 is fixed and the magnetic shield 12 in a coupled state. When connecting them, first the holder 13
The locking part 13a is inserted into the back side of the flange part 9a through the rectangular hole 9b of the frame 9. Further, in order to position the magnetic shielding body 12 on the frame 9, the tongue piece 12b is inserted into the rectangular hole 9b, and the flange portion 12a is abutted against the flange portion 9a. After this positioning, the locking portion 13a of the holder 13 is locked to the back surface of the flange portion 9a, and the pressing protrusion 13b is pressed against the outer surface of the magnetic shielding body 12, and the other end of the holder 13 13c is bent and locked to the locking portion 12c provided on the magnetic shield body 12, so that the magnetic shield body 12 positioned as described above is fixed to the frame 9 as it is.

Here, as shown in FIG. 3, the frame 9 and the magnetic shield 12 are connected by four holders 13 at both long sides 14, 14, so there are no processing errors or deformations during handling. As a result, when the holder shown in FIG. 6 is attached, the pressing protrusion 13b that prevents lateral movement is excessively pressed against the magnetic shielding body 12, and the reaction force causes distortion in the frame 9, resulting in the above-mentioned As a result, the electron beam passing hole 2H of the shadow mask 2 (FIG. 2) is misaligned, and the color purity is impaired.

[Summary of the invention]

This invention was made in order to eliminate the above-mentioned drawbacks, and by absorbing the excessive stress caused by attaching the magnetic shield to the frame and preventing frame distortion, the positional shift of the electron beam passage hole of the shadow mask can be prevented. That is, it is an object of the present invention to provide a magnetic shield mounting structure for a color picture tube that avoids deterioration of color purity.

[Embodiments of the invention]

Embodiments of the present invention will be described below based on the drawings.

FIG. 7 is a perspective view of a main part of a magnetic shield of a color picture tube according to an embodiment of the present invention. As shown in this figure, cut portions 12d are formed on both sides of the base of a tongue piece 12b formed by partially cutting out the flange portion 12a of the magnetic shielding body 12. For example, in a 14-inch color picture tube, the width W and height H of this notch 12d are W=1 to 4 mm and H=1 to 4 mm.
It can be 7 mm.

Note that the other configurations are the same as the conventional one, and therefore the description thereof will be omitted.

As shown in FIG. 6, when the holder 13 is attached and the magnetic shield body 12 is attached to the frame 9, the pressing protrusion 13b of the holder 13 in the configuration shown in FIG. By providing the portions 12d, 12d, it is directly pressed between the notches 12d, 12d, that is, the outer surface of the tongue piece 12b of the magnetic shielding body 12. Therefore, the tongue piece 12b bends appropriately against excessive pressure from the pressing protrusion 13b. That is, when connecting the frame 9 and the magnetic shielding body 12, excessive stress generated due to processing errors or the like is absorbed by the deflection of the tongue piece 12b at the notch 12d, and the distortion of the frame 9 due to the excessive stress is absorbed. is prevented.

〔Effect of the invention〕

As described above, according to the magnetic shield mounting structure for a color picture tube of the present invention, excessive stress caused by mounting the magnetic shield to a frame provided with a shadow mask is absorbed, and distortion of the frame is prevented. This has the effect of avoiding displacement of the electron beam passage hole of the shadow mask, that is, a decrease in color purity.

[Brief explanation of drawings]

Fig. 1 is an exposure process diagram of a phosphor layer, Fig. 2 is an explanatory diagram of the operation of a color picture tube, Fig. 3 is a perspective view showing the state of connection between a conventional frame and a magnetic shield, and Figs. b is a front view and a side view of a conventional holder, FIG. 5 is a perspective view showing the main parts of a conventional frame and magnetic shield, and FIG. 6 is a sectional view showing the state of connection between the conventional frame and magnetic shield. , FIG. 7 is a perspective view showing essential parts of a magnetic shielding body according to an embodiment of the present invention, and FIG. 8 is an explanatory view of the operation of the present invention. 2... Shadow mask, 9... Frame, 9a
... Flange part, 9b ... Rectangular hole, 12 ... Magnetic shield body, 12b ... Tongue piece, 12c ... Locking part, 12d ... Notch part, 13 ... Holder, 13a
... Locking piece, 13b ... Pressing protrusion, 13c ... Other end. Note that the same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Claims] 1. A rectangular hole was provided in the flange of the picture frame to which the shadow mask was fixed, and a tongue protruding from the end of the magnetic shield was inserted into the rectangular hole, and was provided at one end of the plate-shaped holder. While the locking piece is locked to the back surface of the flange portion through the rectangular hole and the pressing protrusion provided on the holder is acting on the outer surface of the magnetic shield, the other end of the holder is In a color picture tube that is bent and locked to a locking part provided on a magnetic shield,
A structure for attaching a magnetic shield to a color picture tube, characterized in that the pressing protrusion acts on the tongue by providing notches on both sides of the base of the tongue.