JPS60221934A - Picture tube - Google Patents

Abstract

PURPOSE:To produce a picture tube having excellent raster shape and resolution with low cost by uniforming the vertical deflection field while employing the horizontal defection field of pincushion distribution and converting the cathode side into strong barrel distribution by means of first and second magnetic chips. CONSTITUTION:A deflection yoke 11 is provided with a horizontal deflection coil 12, a vertical deflection coil 13 and a core 14 where the horizontal deflection coil 12 will produce horizontal deflection field of pincushion distribution. The magnetic field section near the inlet (cathode side) will function onto the first and second magnetic chips 9, 10. While the vertical deflection coil 13 will produce the vertical deflection field of uniform distribution. First and second magnetic chips 9, 10 are formed approximately into T-shape by folding a rectangular magnetic metal plate convexly while central blade sections 9a, 10a are projected along the vertical axis 16 or the central axis of the pincushion face of horizontal deflection field where the projected ends 9b, 10b of said blades 9a, 10a are facing each other while holding an electron beam path 17 between them.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a picture tube device comprising a picture tube and a deflection yoke attached to the picture tube.

Conventional configurations and their problems Picture tubes used as display tubes in computer terminal equipment, word processors, etc. are required to be of particularly high quality. In particular, it is desirable to obtain a neat rectangular raster with high resolution not only in its central region but also in its peripheral regions.

The resolution in the peripheral region of the raster is affected not only by the structure of the electron gun, the deflection angle of the picture tube, the curvature of the phosphor screen surface, etc., but also by the distribution of the deflection magnetic field ek. The shape of the raster is also greatly affected by the deflection magnetic field distribution.

Since the lines of magnetic force of the uniformly distributed deflection magnetic field are linear along the horizontal dimension or the vertical direction, the magnetic field strength is constant regardless of the distance from the tube axis (off-axis distance). Therefore, no deflection distortion occurs in the electron beam passing through it. On the other hand, in the deflection magnetic field of the pink tunnel distribution, the lines of magnetic force are curved in a pincushion shape, so the magnetic field strength increases as the distance from the tube axis increases, and the electron beam passing through this field has different magnitudes between the center/U part and the outer peripheral part. Since it is subjected to a deflection action, deflection distortion occurs. In addition, in the barrel-distributed deflection magnetic field, the lines of magnetic force are curved in a funnel shape, so the magnetic field becomes weaker as the distance from the tube axis increases, causing deflection distortion in the passing electron beam. and,
When the deflected electron beam with deflection distortion impinges on the peripheral area of the phosphor screen surface, the beam spot (bright spot) generated in the area becomes non-circular, making it difficult to obtain high resolution. On the other hand, the shape of the raster becomes a tight rectangle only when a deflection magnetic field with a Binkutsu/Tan distribution is applied, and it becomes a pincushion shape when a deflection magnetic field with a uniform distribution or a barrel distribution is applied.

In general, a deflection yoke in a low-cost monitor picture tube device is configured to provide a deflection magnetic field with a bin cushion distribution, so that a rectangular raster can be generated without using correction means.

However, the deflection distortion of the electron beam is severe, making it impossible to obtain high resolution, especially in the peripheral region of the raster. On the other hand, high-end picture tube devices for monitors often use a deflection yoke that generates a uniformly distributed magnetic field in order to give priority to resolution and therefore image quality. In this case, the raster shape is pincushion-shaped and is corrected using the magnetic field from all the strong permanent magnets, but in normal correction using four permanent magnets,
The outer edge of the raster is not a perfectly straight line, but a curved line. Furthermore, a mechanism for precisely adjusting the correction magnetic field produced by the permanent magnet is required, leading to increased costs.

The shape of the raster is greatly influenced by the magnetic field distribution near the maximum magnetic flux density of the deflection magnetic field and near the exit (screen side), and is influenced by the magnetic field distribution near the entrance (cathode side) of the deflection magnetic field. do not have. Therefore, the magnetic field near the entrance is distorted into a barrel distribution,
If the magnetic field near the exit is distorted into a bin cushion distribution, the deflection distortion of the electron beam can be reduced by canceling out the two distortions, and moreover, the raster shape can be made into a substantially rectangular shape. However, if we try to generate a magnetic field with such a distribution using only the deflection yoke, we will need so-called non-radial windings with different winding distributions near the entrance and near the exit, which will be very expensive. .

Therefore, such a deflection yoke is not suitable for a picture tube apparatus for a monochrome display.

The purpose of the invention is to provide a picture tube device that is satisfactory in terms of total cost, quality, raster shape, and cost.

Structure of the Invention According to the picture tube device of the present invention, a picture tube including first and second magnetic pieces attached to the tip of an electron gun is used,
The vertical deflection coil of the deflection yoke attached to this generates a uniformly distributed vertical deflection magnetic field. Further, the horizontal deflection coil generates a horizontal deflection magnetic field with a bin cushion distribution that partially extends to the first and second magnetic pieces, and the first and second magnetic pieces each generate the horizontal deflection magnetic field. It is formed into a substantially T-shape with a center wing portion that protrudes along the central axis, and the projecting ends of the center wing portions are arranged so as to face each other across the electron beam path.

DESCRIPTION OF EMBODIMENTS In FIG. 1, an electron gun 2 enclosed in a glass bulb of a monochrome picture tube 1 has a cathode 3, a G1 electrode 4,
, a unipotential type equipped with a G2 electrode 6, a G3 electrode 6, a G4 electrode 7, and a G6 electrode 8.
and second magnetic pieces 9, 10 are attached. Also,
A deflection yoke 11 attached to the picture tube 1 has a horizontal deflection coil 12, a vertical deflection coil 13, and a core 14, and the horizontal deflection coil 12 generates a horizontal deflection magnetic field with a Binkuthorn distribution. The magnetic field portion near the entrance (on the cathode side) acts on the first and second magnetic pieces 9 and 10. On the other hand, the vertical deflection coil 13 generates a uniformly distributed vertical deflection magnetic field.

The horizontal deflection magnetic field generated by the horizontal deflection coil 12 exhibits a magnetic flux density distribution as shown in FIG. 2, for example. That is, the magnetic flux density distribution on the tube axis Z is the same as that of the cathode 11!
It gradually becomes stronger as it moves from I (front of the figure) toward the screen, and after reaching the maximum point 0, it gradually becomes weaker. The magnetic flux density distribution at the off-axis position shows a similar tendency, but when the tube axis Z
There is a part a (bottle cushion distribution part) where the magnetic flux density is stronger than the above magnetic flux density, and parts s and c (barrel distribution part) where it is weaker. The latter is a weak field that occurs locally due to the circumstances of the winding, and the deflection magnetic field as a whole has a pink non-yon distribution.

The magnetic flux density distribution at the tube axis "2" of the horizontal deflection magnetic field is
A protruding portion as shown as A in the figure is produced.

This is a magnetic flux density region enhanced by attaching the first and second magnetic pieces 9 and 10.

The first and second magnetic pieces 9, 10 are formed into a substantially T-shape as shown in FIG. This is obtained by bending a rectangular magnetic metal plate made of iron-nickel alloy (50%ye, 5o%Ni) etc. into a convex shape, and the central wing parts 9 & 10a are the center of the pincushion surface of the horizontal deflection magnetic field. The central wing portion 9ia is arranged to protrude along the vertical axis 16.

The protruding ends 9b and 10b of 10a are connected to an electron beam path 17.
They are facing each other with the two sides in between.

First and second magnetic pieces9. IQff: The two supporting nonmagnetic metal pieces 18 and 19 have one end fixed to the large diameter tip of the 06 electrode 8, and support the ring getter 20 at the other end. In addition, the centering claws 23, 24, 25.26 formed at the tips of the branching wing portions 21.22 are
The tongue-shaped portions 27.28 extending from the branch wing portions 21.22 contact the inner surface of the bulb neck portion to prevent the electron gun from tilting, and the tongue portions 27.28 extend from the branch wing portions 21.22 to contact the conductive film (not shown) attached to the inner surface of the bulb. ,
A high voltage supplied through this conductive film is applied to the G5 electrode 8 and the G3 electrode 6.

As shown in FIG. 5, the first and second magnetic pieces 9.10
On the other hand, when a horizontal deflection magnetic field 29 with a pink nonyon distribution shown by a broken line acts, a small magnetic field 30 with a strong barrel distribution is generated between the two magnetic pieces 9° and 10, and the magnetic flux density in this region is enhanced as described above. be done. On the other hand, both magnetic pieces 9, 1
The uniformly distributed perpendicular deflection magnetic field 31 acting on the magnetic field 31 only passes through both the magnetic pieces 9 and 10.

For this reason, the horizontal deflection magnetic field maintains a pink nonyon distribution at least near the maximum magnetic flux density, while containing a strong barrel distribution part in the cathode side region that does not contribute to the raster shape, resulting in a rectangular rectangular raster with little distortion. At the same time, the effect of reducing deflection distortion is obtained, and the heel spot becomes nearly a perfect circle over the entire area of the phosphor screen surface, making it possible to obtain high resolution.

The arrangement positions of the first and second magnetic pieces 9, 1Q are closely related to the deflection (magnetic flux distribution and distribution of the a field), and both magnetic pieces 9, 10 (as shown in FIG. It should be arranged in the magnetic flux density region on the cathode side, which corresponds to 20-80% of the maximum value of the two-axis magnetic flux density distribution.

Effects of the Invention As described in Section 2, in the present invention, the vertical deflection magnetic field in the short side direction, where the deflection angle is relatively small and therefore has little raster distortion, is made uniform to eliminate vertical deflection distortion, while the horizontal deflection magnetic field in the long side direction In this method, a magnetic field with a bottle cushion distribution is generated by a deflection coil, and the cathode side is converted into a strong barrel distribution by the first and second magnetic pieces, and both raster distortion and deflection distortion in the horizontal direction are drastically reduced. therefore,
By simply arranging a pair of magnetic pieces inside the tube, it is possible to obtain a picture tube device with excellent raster shape and resolution at low cost. Note that the raster distortion in the vertical direction is small as described above, and can be corrected simply by placing a weak correction permanent magnet outside the tube.

[Brief explanation of drawings]

Fig. 1 is a diagram of the electrode configuration of a picture tube device embodying the present invention, Fig. 2 is a diagram schematically showing the magnetic flux density distribution of the magnetic field generated by the water deflection coil of the same device, and Fig. 3 is a diagram of the same device. Fig. 4 is a perspective view of the main parts of the device;
FIG. 6 is a deflection magnetic field distribution diagram of the same device. 2... Electron gun, 9, 10... Magnetic piece, 12... Horizontal deflection Koinope 13... Vertical deflection coil. Name of agent: Patent attorney Toshio Nakao and 1 other person 2nd
Figure 3 Man 4 Figure 1'7

Claims (1)

[Claims] The electron gun includes a picture tube in which first and second magnetic pieces are installed at the tip of the electron gun, and a deflection yoke closely attached to the picture tube, and the deflection yoke generates a vertical deflection magnetic field with a uniform distribution. a horizontal deflection coil that generates a horizontal deflection magnetic field with a pink 1-5 distribution that partially extends to the first and second magnetic pieces; are each formed in a substantially T-shape having a medium flame wing portion protruding along the central axis of the horizontal deflection magnetic field,
A picture tube device characterized in that the protruding ends of each of the medium flame wing portions face each other across an electron beam path.