JPH02142034A - Cathode-ray tube - Google Patents

Abstract

PURPOSE:To obtain a good raster by providing a permanent magnet on a vertical axis of a deflecting yoke so as to form a magnetic field by which an electron beam is deflected vertically, and by providing a piece of a magnetic substance with which a magnetic pole of the permanent magnet is magnetically linked. CONSTITUTION:A pair of permanent magnets 23 are formed on a vertical axis Y of a deflecting yoke 19 in symmetry upward and downward to a horizontal axis X, so as to form a magnetic field by which an electron beam is deflected vertically. This is horizontally extended so that a magnetic pole of the permanent magnet 23 and one end are linked together magnetically, and the other end is receded from the vertical axis Y, while a piece of magnetic substance 24 is provided so that the other end is situated closer to the horizontal axis X than the magnetic pole of the permanent magnet 23. Pin cushion type distortion of the upper and lower parts of the display can be adjusted by a pin cushion type magnetic field that is generated by the magnetic pole of the permanent magnet 23, as well as the drop of the end of the distortion of high degree can be adjusted by the magnetic field generated by the end of the piece of the magnetic substance 24. A good raster can thus be obtained.

Description

[Detailed Description of the Invention] [Objective of the Invention] (Industrial Application Field) The present invention relates to a cathode ray tube device such as a color picture tube with a deflection yoke, and in particular to correction of raster distortion by correcting the deflection of an electron beam. The present invention relates to a cathode ray tube device.

(Prior Art) Generally, in a color picture tube, an electron beam emitted from an electron gun disposed inside the neck of the envelope is deflected horizontally and vertically by a deflection yoke attached to the outside of the envelope. By scanning the phosphor screen through a shadow mask, a color image is displayed on the phosphor screen. In this color picture tube, in order to display a correct color image on the phosphor screen, it is necessary to correctly focus three electron beams over the entire surface of the phosphor screen.

In order to obtain correct concentration of the three electron beams with a relatively simple configuration, an in-line three-electron gun is used that emits three electron beams arranged in a row, consisting of a center beam and a pair of side beams that pass on the same horizontal plane. By taking advantage of the characteristics of this in-line arrangement of three electron guns, the deflection magnetic field formed by the deflection yoke is made into a non-uniform magnetic field, thereby concentrating the three electron beams over the entire surface of the phosphor screen. There is a picture tube. Generally, as for the nonuniform magnetic field of the deflection yoke, the horizontal deflection magnetic field formed by the horizontal deflection coil is generally pincushion-shaped, and the vertical deflection magnetic field formed by the vertical deflection coil is generally barrel-shaped. By making the deflection magnetic field a specific non-uniform magnetic field, the three electron beams are focused correctly and the pincushion-shaped raster distortion that normally occurs at the top and bottom of the screen is also corrected.

However, even if the deflection magnetic field is a nonuniform magnetic field, in the case of a wide deflection angle tube, for example, a color picture tube with a deflection of about 110 degrees, the horizontal deflection magnetic field formed by the horizontal deflection coil can completely eliminate both the concentration of the three electron beams and the raster distortion. It becomes difficult to correct for this. Therefore, as shown in FIGS. 6 and 7, the vertical axis (
A pair of permanent magnets (1), (1) that generate a magnetic field that deflects the electron beam in the vertical direction are installed on the horizontal axis (X-axis) vertically symmetrically with respect to the horizontal axis (X-axis). Some devices correct the pincushion-shaped raster distortion at the top and bottom of the screen by correcting the magnetic field. Note that in FIGS. 6 and 7, (2) is a vertical deflection coil, and (3) is a horizontal deflection coil.

By the way, as the screen becomes flat as in recent color picture tubes, it becomes difficult to design the deflection yoke, and in addition, the screen becomes aspherical, which causes not only the simple pincushion-shaped raster distortion mentioned above but also the As shown in FIG. 8, a high-order distortion (5) called so-called Seagull distortion occurs above and below the screen (4).

This high-order distortion (5) is difficult to correct simply by attaching a permanent magnet to the deflection yoke as described above, and cannot be corrected even by adjusting the magnetic field distribution of the horizontal deflection coil.

(Problems to be Solved by the Invention) As mentioned above, in order to correct the concentration of three electron beams and the pincushion-shaped raster distortion at the top and bottom of the screen of in-line color picture tubes, especially wide deflection angle color picture tubes,
Some devices have a permanent magnet attached to the end of the deflection yoke on the phosphor screen side.

However, even if permanent magnets are attached in this way, it is difficult to correct high-order distortions that occur on a flat and aspheric screen.

The present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to make it possible to obtain a good raster image without greatly deteriorating the concentration of electron beams over the entire screen.

[Structure of the Invention] (Means for Solving the Problems) A deflection yoke that deflects an electron beam emitted from an electron gun in horizontal and vertical directions is provided, and the horizontal deflection magnetic field of this deflection yoke is generally pincushion-shaped. In a certain cathode ray tube device, a pair of permanent magnets that form a magnetic field that vertically deflects the electron beam are provided on the vertical axis of the deflection yoke, vertically symmetrical with respect to the horizontal axis, and the magnetic poles of the permanent magnets and one end thereof are arranged vertically symmetrically with respect to the horizontal axis. magnetically coupled, the other end extends in the horizontal direction away from the vertical axis, and the other end is located closer to the horizontal axis than the magnetic pole of the permanent magnet. has been established.

(Function) As described above, if a permanent magnet is provided on the vertical axis of the deflection yoke to form a magnetic field that deflects the electron beam in the vertical direction, and a magnetic piece is provided that magnetically couples with the magnetic pole of this permanent magnet. , the pincushion-shaped magnetic field generated from the magnetic poles of the permanent magnet corrects the pincushion-shaped distortion near the vertical axis at the top and bottom of the screen, and at the same time, the magnetic field generated from the end of the magnetic piece nearly parallel to the horizontal axis corrects the pincushion-shaped distortion near the vertical axis. , it is possible to correct the dip in the edges of higher-order distortions.

(Example) Hereinafter, the present invention will be described based on an example with reference to the drawings.

FIG. 1 shows a self-convergence type in-line color picture tube device which is an embodiment of the present invention. This color picture tube device includes a panel (10) and this panel (1).
0) and an integral funnel (11).
), and on the inner surface of the panel (10) is a phosphor screen (13) consisting of three-color phosphor layers that emit light in blue, green, and red.
A shadow mask (14) is mounted inside the panel (10) facing the phosphor screen (13). Also, the neck (15) of the funnel (11)
Inside, there is a center beam (16G) and a pair of side beams (16B) that pass on the same horizontal plane.

An in-line array of three electron guns (17) that emits three electron beams consisting of (16R) is provided. Further, on the outside of the boundary between the cone portion (18) and the neck (15) of the funnel (11), a deflection yoke ( 19) is installed.

This deflection yoke (19) forms a non-uniform magnetic field in the passage area of the three electron beams, and as shown in FIGS. A pair of upper and lower saddle-shaped horizontal deflection coils (3) form a horizontal deflection magnetic field, and a pair of upper and lower toroidal-shaped vertical deflection coils (2) form a barrel-shaped vertical deflection field outside the insulating molded member (21). Core (22
) are wrapped and arranged.

Furthermore, in this deflection yoke (19), a pair of permanent magnets (23) with magnetic poles at both ends are provided on the vertical axis of the opening end on the phosphor screen side, parallel to the horizontal axis. There is. The magnetic pole arrangement of each permanent magnet (23) is
The arrangement is such that the three electron beams are deflected upward at the top of the screen and downward at the bottom of the screen. Roughly, each permanent magnet (2
A pair of single-shaped magnetic pieces (24), (24) are arranged on both sides of 3L (23).

Each magnetic piece (24) has a permanent magnet (23) at one end.
The other end extends along the horizontal axis away from the vertical axis, and the bent tip is connected to the magnetic pole of the permanent magnet (23). The arrangement is closer to the horizontal axis.

As described above, a pair of permanent magnets (23), (23) are provided on the vertical axis of the open end of the deflection yoke (19) on the phosphor screen side, parallel to the horizontal axis, and the permanent magnets 1a? Ei
(23L) When the magnetic pieces (24), (24) that magnetically couple with the magnetic poles of (23) are arranged, each permanent magnet (23), (23) is generates a magnetic field (26) to correct the barrel-shaped vertical deflection magnetic field near the vertical axis of the vertical deflection coil, and corrects the pincushion-shaped distortion near the vertical axis at the top and bottom of the screen.At the same time, each permanent magnet (23), Between the magnetic material piece (24) magnetically coupled with the magnetic pole of (23), and the tip of the other end of (24), there is a magnetic field that is more parallel to the horizontal axis than the magnetic field (26) between the magnetic poles. (27) is generated. This magnetic field (27) is dense and strong near the tips of the magnetic pieces (24), (24).
It gets weaker as you move away. Therefore, this magnetic field (
27), it is possible to correct the barrel-shaped vertical deflection magnetic field at a position away from the vertical axis of the vertical deflection coil, and to correct the depression of the edges of high-order distortion at the top and bottom of the screen.

Note that since the magnetic pieces (24), (24) in this example are provided at the open end of the deflection yoke (19) on the phosphor screen side, their influence on the concentration of the three electron beams is small.

In the above embodiment, a case was described in which magnetic pieces in the shape of a single character were arranged, but as shown in FIG. may be arranged at an angle with respect to the la pole of the permanent magnets (23), (23) so that the tip approaches the horizontal axis.

In short, the magnetic piece according to the present invention is magnetically coupled to the magnetic pole of a permanent magnet, the other end extends along the horizontal axis in a direction away from the vertical axis, and the other end extends horizontally between the tip parts. It is important to position the tip of the other end closer to the horizontal axis than the magnetic poles of the permanent magnet so as to generate a magnetic field nearly parallel to the axis. Further, in the above embodiment, one end of the magnetic material piece was placed in close contact with the ia pole of the permanent magnet, but the one end of this magnetic material piece only needs to be magnetically coupled with the magnetic pole of the permanent magnet, and it is not necessary that the end portion of this magnetic material piece be in close contact with the magnetic pole of the permanent magnet. There's no need.

In the above embodiment, the horizontal deflection coil of the deflection yoke was described as a saddle type, and the vertical deflection coil was of a 1 to loidal type. Any type of magnetic field that forms a nonuniform magnetic field may be used, for example, a combination of a saddle-shaped horizontal deflection coil and a saddle-shaped vertical deflection coil may be used.

Furthermore, since the present invention is aimed at correcting raster distortion on a screen, it is not particularly limited to color picture tubes, but can also be applied to black cathode ray tubes.

[Effect of the invention] In a cathode ray tube device in which the horizontal deflection magnetic field of the deflection yoke that deflects the electron beam emitted from the electron gun is generally pincushion-shaped, the electron beam is deflected in the vertical direction on the vertical axis of the deflection yoke. A permanent magnet is provided to form a magnetic field that
By providing a magnetic piece that magnetically couples with the magnetic poles of the permanent magnet, the pincushion-shaped magnetic field generated from the magnetic poles of the permanent magnet corrects the pincushion-shaped distortion at the top and bottom of the screen, and at the same time, the edge of the magnetic piece The generated magnetic field can correct the collapse of the edges due to high-order distortion, making it possible to provide a cathode ray tube device that displays images with good quality.

[Brief explanation of the drawing]

1 to 5 are detailed explanatory diagrams of the present invention. FIG. 1 is a sectional view showing the configuration of a self-convergence type in-line color picture tube as an embodiment of the invention, and FIG. 2 is a sectional view of the deflection yoke. 3 is a front view thereof, FIG. 4 is an explanatory diagram of the operation of the deflection yoke, FIG. 5 is a front view showing the structure of the deflection yoke of another embodiment, and FIG. 6 is a conventional one. FIG. 7 is a perspective view showing the configuration of a deflection yoke of a self-convergence type in-line color picture tube, FIG. 7 is a front view thereof, and FIG. 8 is a diagram showing high-order distortion appearing on the screen. 12... Envelope 13... Phosphor screen 14... Shadow mask 16R, 16B... Pair of side beams 16G...
Center beam 17...electron gun 19...deflection yoke 23
...Permanent magnet 24...Magnetic material piece Agent Patent attorney Norio Ogo No. 4 Fig. 3 Fig. 8

Claims (1)

[Claims] A deflection yoke is provided that forms a horizontal deflection magnetic field and a vertical deflection magnetic field that deflect an electron beam emitted from an electron gun in horizontal and vertical directions, and the horizontal deflection magnetic field of this deflection yoke is comprehensively pincushioned. In the cathode ray tube apparatus, a pair of permanent magnets are provided on the vertical axis of the deflection yoke, vertically symmetrical with respect to the horizontal axis, to form a magnetic field that deflects the electron beam in the vertical direction, and the magnetic poles of the permanent magnets and A magnetic body having one end that is magnetically coupled, the other end extending horizontally away from the vertical axis, and the other end being located closer to the horizontal axis than the magnetic poles of the permanent magnet. A cathode ray tube device characterized by having a strip.