JPH0210711Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to a picture tube device that is used in display devices and the like and has a magnetic shielding function.

[Prior Art] Conventionally, as a picture tube device having a magnetic shielding function, the one shown in the schematic diagram of FIG. 4 is known. In the figure, 1 is a picture tube, and 2 is this picture tube 1.
1b is a phosphor layer coated in a mosaic pattern on the inner surface of the panel glass 1a;
Funnel-shaped funnel glass fused to a, 1
Reference numeral c denotes a neck portion extending long and thin toward the rear of the funnel glass 1b, and a plurality of electron guns 4 that emit electron beams 100B, 100G, and 100R are enclosed within the neck portion 1c. electron beam 100
B, 100G, and 100R indicate blue, green, and red electron beams, respectively.

5 is a deflection yoke attached to the outer periphery of the cone portion 1d of the funnel glass 1b, and the three electron beams 100B and 100 emitted from the electron gun 4 are
G, 100R by electromagnetic field, panel glass 1a
This is for deflecting the light vertically and horizontally onto a screen constituted by a phosphor layer 2 on the inner surface of the screen.

Reference numeral 6 denotes a convergence spirit magnet, generally called a CP magnet or CP assembly, which is installed on the network part 1c, and is connected to the three electron beams 1 emitted from the electron gun 4.
By slightly changing the orbits of 00B, 100G, and 100R, three electron beams 100 at the center of the screen
Concentration of B, 100G, and 100R (generally referred to as static convergence) and color purity correction are performed.

Reference numeral 7 denotes an inner coating dac formed on the inner surface of the funnel glass 1b, which maintains the inner surface of the funnel glass 1b at a uniform potential, and an anode button (not shown) provided on the opening side of the funnel glass 1b. ) serves to conduct the high voltage potential supplied from the electron gun 4 to the tip of the electron gun 4.

Conventionally, in order to prevent the high-frequency magnetic field from the deflection yoke 5 from leaking to the outside, a cup-shaped magnetic shield is provided that extends from the rear end of the deflection yoke 5 toward the funnel glass 1b, as shown in FIG. 9 is known in which the deflection yoke 5 is covered.

[Problem that the invention aims to solve] Many recent color picture tubes use the ITC method, which sets the purity and convergence adjustments in advance before installing them in the TV set. This method eliminates the need for any adjustment around the color picture tube by simply attaching the color picture tube to the TV set.

However, when the color picture tube manufactured in this way is installed in the final set for adjustment using a specific TV set during ITC, the magnetic shield 9 does not cover the setting part of the electron gun 4. Therefore, a time-varying leakage magnetic field from the outside such as the flyback transformer 8 is applied to the focusing electrode system of the electron gun 4, often causing misconvergence. Therefore, when misconvergence occurs, it is necessary to readjust the PC magnet 6 again.

However, readjustment is extremely difficult for those who are inexperienced with ITC work, takes a considerable amount of time, and sometimes results in loss as the ITC must be returned to the ITC manufacturer for readjustment, and readjustment is difficult. Therefore, a slight misconvergence is ignored, resulting in a TV set with degraded convergence quality.

Therefore, conventionally, as shown in FIG. 5, a plurality of plate-shaped magnetic shields 10 extending radially from the neck portion 1c of the funnel glass 1b are arranged to sandwich both axial ends of the CP magnet 6 or It is fixed to the magnet ring itself of 6,
A device is known that prevents external leakage magnetic flux Φ from being applied to the focusing electrode system of the electron gun 4 due to a flyback transformer 8 or the like.

However, the magnetic shield body 10 is not suitable for the electron gun 4.
Since the leakage magnetic flux Φz is set to interlink with the leakage magnetic flux Φz along the axial direction of the electron gun 4, it is possible to prevent this leakage magnetic flux Φz from being applied to the focusing electrode system of the electron gun 4. There is a drawback that the leakage magnetic flux Φx is added to the focusing electrode system of the electron gun 4, causing misconvergence.

Therefore, as shown in FIG. 6, it is conventionally known to cover the entire outer periphery of the deflection yoke 5 and the neck portion 1a with a magnetic shield 11.

However, since the magnetic shielding body 11 is made of a magnetic material, when a time-varying leakage magnetic field from the outside such as the flyback transformer 8 is applied to the magnetic shielding body 9, it is magnetized and the electron beam is emitted. The trajectory changes and readjustment is required.

This idea was made to improve the above-mentioned drawbacks, and when the convergence-adjusted picture tube is assembled into a unit as a picture tube device, the temporally varying leakage magnetic field from the outside due to a flyback transformer etc. It is an object of the present invention to provide a picture tube device that does not affect the trajectory of the image tube, does not require readjustment, can realize high-quality convergence, and has a magnetic shield that can be easily attached and detached.

[Means for solving the problem] This invention covers the deflection yoke, the magnet, and the focusing electrode system integrally and annularly with a non-magnetic conductive magnetic shield, and covers the front end of the coil bobbin constituting the deflection yoke. Alternatively, it is characterized in that the magnetic shield is removably fixed to the rear end overhang.

[Function] In this invention, when a picture tube with convergence adjustment is assembled into a picture tube unit as a picture tube device, when a leakage magnetic field that changes over time from the outside by a flyback transformer or the like is applied to the magnetic shield body. Since this magnetic shield is non-magnetic, it will not become magnetized and affect the trajectory of the electron beam.

Furthermore, since the magnetic shield is made of a conductive material and covers the focusing electrode system of the electron gun in an annular manner, when the leakage magnetic field is applied to the magnetic shield, the annular magnetic shield The generated eddy current generates a new magnetic field that erases the leakage magnetic field, which can eliminate or reduce the leakage magnetic field that affects the trajectory of the electron beam, thereby preventing misconvergence. It is possible to eliminate it.

Furthermore, by removably fixing the magnetic shield to the front end or rear end overhang of the coil bobbin constituting the deflection yoke, the fixing structure is simplified and the fixing work is also facilitated.

[Embodiment] FIG. 1 shows an embodiment of the picture tube device according to this invention. In the figure, the same parts as in FIGS. 4 to 6 are given the same reference numerals.

In FIG. 1, the deflection coil 5 includes a pair of toroidal coils 13 wound in a toroidal manner around a core 12, a pair of saddle-shaped coils 14, and a pair of saddle-shaped coils 14 on the inner peripheral surface. It is composed of a coil bobbin 15 which is attached to the coil bobbin 15 and has an insulating function for both the coils 13 and 14. The bobbin 15 is a cone portion 1d of funnel glass 1b.
It is formed in a cone shape along the outer periphery of the coil, and has a front end extension part 15a for housing the front end folded part 14a of the saddle-shaped coil 14 at its front end, and a rear end folded part 14b of the saddle-shaped coil 14 at its rear end. Each has a rear end overhang portion 15b for storage.

The bobbin 15 is firmly fixed to the neck portion 1c by fitting a tightening band 16 onto a cylindrical portion 15c having an axial notch protruding from its rear end.

In the PC magnet 6, a pair of six-pole magnets 18, a four-pole magnet 19, and a two-pole magnet 20 are inserted in this order into the outer periphery of the holder 17 from the rear end side to the front end side of the neck portion 1c. After a washer 21 is inserted between the pole magnets, a spring washer 22 is inserted, and finally a screw-tight lock ring 23 is screwed into the thread of the holder 17 to assemble the unit.

The holder 17 is firmly fixed to the neck portion 1c by fitting a tightening band 24 onto a cylindrical portion 17a having an axial notch protruding from its rear end.

By adjusting the opening angle and rotation angle of the pair of two-pole magnets 20, the purity of the color picture tube is adjusted. On the other hand, the static convergence is adjusted by adjusting the opening angle and rotation angle of the set of 4-pole magnet 19 and 6-pole magnet 18, and finally the locking ring 23 is adjusted.
By tightening the screws, each magnet 1
Fix 8, 19, and 20 so that they do not move.

In this way, the PC magnet 6 is placed above the electron gun 4 enclosed in the neck portion 1c of the color picture tube, and is mainly used for adjusting the power and static convergence.

The electron gun 4 includes cathode bodies KR, KG, KB, a control electrode body G1, an acceleration electrode body G2, a focusing electrode body G3, and an anode body G4 each having the same potential as the shadow mask 3 and the phosphor layer 2 shown in FIG. It consists of Each of the electrode bodies G3 and G4 constitutes an electron beam focusing electrode system.

In addition, the above-mentioned focusing electrode body G3 is 1 for simplicity of illustration.
Although the case of a book is described, it goes without saying that this also includes cases where the book is divided into multiple parts.

Now, in FIG. 1, when the electron gun 4 is in operation, a high voltage of 0V or more is applied to the cathode bodies KR, KG, KB, 8KV to the focusing electrode body G3, and 20KV or more to the anode body G4, so that the phosphor is The electron beam is designed to be focused on layer 2.

A cup-shaped magnetic shield 25 extends from the front end of the deflection yoke 5 toward the neck portion 1c of the picture tube, and the magnetic shield 25 is made of a non-magnetic conductive material such as aluminum or copper. It covers the outer circumferences of the deflection yoke 5 and the electron gun 4, and its front end 25a is fixed to the front end extension 15a of the bobbin 15 by a screw body 26.

As is clear from the above configuration, the entire outer periphery of the deflection yoke 5 and the neck portion 1c is covered by the magnetic shield 25.
Since the magnetic shield body 25 is made of a magnetic material, as shown in FIG. Even if it is added to the shield body 25, it will not be magnetized and will not change the trajectory of the electron beam.
There is no need to readjust the power and static convergence using the CP magnet 6.

Furthermore, since the magnetic shield body 25 is made of a conductive material and covers the focusing electrode systems G3 and G4 of the electron gun 4 in an annular manner, when the leakage magnetic field is applied to the magnetic shield body 25, this The eddy current generated in the annular magnetic shielding body 25 generates a new magnetic field that erases the leakage magnetic field, and it is possible to erase or reduce the leakage magnetic field that affects the trajectory of the electron beam. can. Therefore, there is no need to readjust the power and static convergence using the CP magnet 6.

Moreover, since the magnetic shielding body 25 annularly covers not only the focusing electrode systems G3 and G4 of the electron gun 4 but also the deflection yoke 5 with a non-magnetic conductive material, leakage magnetic flux from the flyback transformer 8, etc. The focusing electrode system G of the electron gun 4 passes through the core 12 of 5.
3, it is possible to prevent the signal from being applied to G4.

Furthermore, since the magnetic shielding body 25 is removably fixed to the front end or rear end protruding portions 15a, 15b of the coil bobbin 15 constituting the deflection yoke 5 by means of a screw body 26, the fixing structure is simplified and Fixing work is also easier.

In the above embodiment, the magnetic shield body 25 was fixed at its front end portion 25a to the front end overhang portion 15a of the bobbin 15 by the screw body 26, but the magnetic shield body 25 was fixed to the rear end overhang portion 15.
b may be fixed by a screw body 26, and
Instead of the screw body 26, a clip 28 as shown in FIG. 3 may be inserted into the through holes 25b, 15c, and the magnetic shield body 25 may be fixed to the front end overhang 15a or the rear end overhang 15b of the bobbin 15. .

[Effects of the invention] As described above, according to this invention, the deflection yoke, the magnet, and the focusing electrode system are integrally and annularly covered with a non-magnetic conductive magnetic shield, and the coil bobbin constituting the deflection yoke is Since the magnetic shielding body is removably fixed to the front end or rear end of the picture tube, when the convergence-adjusted picture tube is assembled into a picture tube device, there is no possibility of temporal changes caused by external forces such as a flyback transformer. It is possible to provide a picture tube device in which the leakage magnetic field does not affect the trajectory of the electron beam, readjustment is unnecessary, high-quality convergence can be achieved, and the magnetic shield can be easily attached and detached.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of the main parts showing an embodiment of the picture tube device according to this invention, FIG. 2 is a cutaway side view showing the main parts for explaining the operation of the picture tube device according to this invention, and FIG. The figure is a cross-sectional view of a main part showing another fixing means for a magnetic shield according to this invention, and FIGS. 4 to 6 are side views showing the main parts of different conventional picture tube apparatuses in cross-section. 1...Picture tube, 1b...Funnel glass, 1c...
Network part, 1d... Cone part, 4... Electron gun, G3,
G4... Focusing electrode system, 5... Deflection yoke, 6... Convergence spirit magnet, 15... Coil bobbin, 15a... Front end overhang, 15b... Rear end overhang, 25... Magnetic shielding body. Note that the same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Scope of Claim for Utility Model Registration] (1) The outer periphery of the deflection yoke attached to the cone of the funnel glass constituting the picture tube, and the outer periphery of the convergence spirit magnet attached to the outer periphery of the neck. The focusing electrode system constituting the electron gun enclosed in at least the neck portion of the picture tube is annularly covered with a nonmagnetic conductive magnetic shield, and the deflection yoke, magnet, and focusing electrode system are integrated. A picture tube device characterized in that a magnetic shield covering the deflection yoke is detachably fixed to a front end or a rear end protrusion of a coil bobbin constituting the deflection yoke. (2) The picture tube device according to claim 1, wherein the shield body is made of aluminum or copper.