JPH0562417B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a device for correcting misconvergence (hereinafter simply referred to as misconvergence) using a deflection yoke without providing a convergence yoke.

BACKGROUND TECHNOLOGY AND PROBLEMS There are two types of misconceptions caused by the assembly accuracy of a deflection yoke or the rotation of the electron gun of a cathode ray tube, which are called cross misconceptions and bow-shaped misconceptions.

As shown in FIG. 1, the cross-miscon is such that the scanning line BR of the red beam R and the scanning line BB of the blue beam B intersect at the center of the screen of the cathode ray tube. On the other hand, the bow-shaped beauty pageant is a beauty pageant in which the scanning lines BR and BB of the red and blue beams R and B are distorted in an arch-shaped manner, and the directions of the distortions are opposite to each other, as shown in FIG.

By the way, it is known that a deflection yoke is used to correct misconvergence without specifically providing such a convergence yoke for correcting misconvergence.

Correction of the cross pageant is performed as follows.

In this case, the horizontal deflection coil is constituted by saddle-shaped coils 1 and 2 arranged one above the other in a direction perpendicular to the tube axis of the cathode ray tube, as shown in FIG. and,
Moreover, the lower horizontal deflection coils 1 and 2 are connected in parallel as shown in FIG. 4, and sub-coils 3 and 4 are connected in series to the respective deflection coils 1 and 2, respectively. These subcoils 3 and 4 have the same inductance when no core is present, but when the core 5 is inserted into these subcoils 3 and 4 as shown in FIG. 5, the upper and lower coils Inductances 3 and 4 are varied to balance the upper and lower deflection magnetic fields, thereby correcting the cross misconductor.

In other words, the inductance of a coil increases in proportion to the length of the core inserted into the coil, so in the case of Fig. 5, the upper subcoil 3
The inductance of the lower subcoil 4 is larger than the inductance of the lower subcoil 4. Therefore, the magnetic field caused by the horizontal deflection yoke becomes stronger than the magnetic field caused by the lower coil 4. Then, the distribution of the deflection magnetic field within the tube axis of the cathode ray tube changes. That is, Figures 6 and 7
The figure explains the magnetic field in the plane perpendicular to the tube axis, in this case red, green and blue beams R,
C and B are arranged inline.

Horizontal direction x at the exact center position of the upper and lower deflection yokes
In this case, if the magnetic fields from the upper and lower coils are balanced, the direction of the magnetic flux φ is perpendicular to the horizontal direction x. However, as mentioned above, when the magnetic field from the lower coil becomes stronger, the position where the direction of magnetic flux is perpendicular to the horizontal direction (hereinafter referred to as the center of the magnetic field) moves upward.
In the horizontal direction x at the exact center of the upper and lower deflection yokes, the magnetic flux φ has an inclination with respect to the vertical direction as shown in FIGS. 6 and 7. Then, when the right side of the screen is deflected, the direction of magnetic flux is upward as shown in Figure 6, but magnetic fields in the x direction are generated in the directions facing each other, which does not occur when the inductances of the upper and lower coils are balanced.
The components H ₁ and H ₂ are formed. Therefore, a force is generated that moves the red beam R toward the bottom of the screen and the blue beam B toward the top of the screen.

On the other hand, when the left side of the screen is deflected, the deflection current is in the opposite direction, so the direction of the magnetic flux φ is downward as shown in FIG _. and H ₄ components are produced. Then, a force is generated that moves the red beam R upward and the blue beam B downward, contrary to the left side of the screen.

Then, considering that the magnetic field due to the coil increases as it is deflected to the left and right, and that H ₁ to _{H 4} also increase accordingly, the cross miscon shown in Figure 1 can be corrected. It is.

The cross misconception described above is corrected because the horizontal deflection currents flow in opposite directions on the left and right sides of the screen, and the red beam R and blue beam B are corrected in opposite directions.

However, in the above-mentioned bow-shaped pageant, as is clear from FIG. 2, the red beam R and blue beam B must be corrected in the same direction on the left and right sides of the screen. Therefore, the above method cannot correct the bow-shaped misconception, and conventionally there has been no method for correcting the bow-shaped misconception using only a deflection yoke.

OBJECTS OF THE INVENTION In view of the above points, it is an object of the present invention to provide a device capable of correcting bow-shaped misconception using a deflection yoke.

Summary of the Invention This invention not only provides cores for the upper and lower sub-coils, but also provides means for applying a bias magnetic field to these cores. It is possible to correct the bow-shaped pageant by reversing the strength of the bow.

Embodiment FIG. 8 shows an example of the configuration of the essential parts of the device of the present invention, in which upper and lower subcoils 3 and 4 connected in series to upper and lower deflection coils 1 and 2 are wound around cores 6 and 7. However, a bias magnetic field is applied to these cores 6 and 7 by a magnet 8.

Assuming that the magnetic poles of the magnet 8 are as shown in the figure, the magnetic field φ _Mg due to the magnet 8 is in the same direction within the cores 6 and 7 as indicated by the arrows in the figure. now,
As can be seen from Figure 9, the inductances when no current flows through coils 3 and 4 are L 3 and L ₃ , respectively.
It becomes L ₄ .

In this state, when the beam scans to the right side of the screen, if current flows through the coils 3 and 4 in the direction shown in Figure 8, the magnetic field φc generated by this will be
becomes larger as it is deflected to the right, and is opposite in direction between coils 3 and 4. For this reason,
The magnetic field on the coil 3 side becomes weaker, and the magnetic field on the coil 4 side becomes stronger, so that the inductance of coil 3 becomes L ₃ ', which is larger than L ₃ , and that of coil 4 becomes
It becomes L _{4 ′} which is smaller than L ₄ . Therefore, it becomes difficult for current to flow through the upper coil, and the deflection magnetic field generated by the lower coil becomes stronger. Therefore, the center of the magnetic field generated by the upper and lower coils is biased upward from the center position of the upper and lower coils, and the magnetic field φ at the center position of the upper and lower coils becomes as shown in FIG. Therefore, magnetic fields H ₅ and H ₆ are generated in the x direction, which is opposite to that shown in Fig. 6.
A force is generated that moves the red beam R downward and the blue beam B upward.

On the other hand, when scanning the left side of the screen, coil 1,
Since the directions of the currents flowing through coils 3 and 2 and 4 are opposite, the magnetic fields φc due to coils 3 and 4 are in opposite directions to those shown in FIG. The inductance of becomes large. Therefore, the center of the magnetic field is biased below the center position of the upper and lower coils, and the direction of the magnetic field φ at the center position of the upper and lower coils is as shown in FIG. Therefore, even if the direction of the deflection current changes, the slope of the magnetic field will change to the right.
Also on the left side, components of magnetic fields H ₇ and H ₈ in the x direction are generated in directions facing each other, and as on the right side, a force is generated that moves the red beam R downward and the blue beam B upward.

As a result of the above, the force in the correction direction of the beam becomes the same on both the left and right sides of the screen, and since the deflection current increases as you go left and right, the force also increases, so that the bow-shaped misconception can be corrected.

The vertical relationship between the red beam R and blue beam B of the bow-shaped beauty pageant shown in FIG. 2 may be reversed, but in that case, the bias magnetic field by the magnet 8 may be reversed.

Also, the coil 3 is relative to the cores 6 and 7.
By changing the length of the core inserted into each coil by changing the length of the core inserted into each coil, the cross misconception can be corrected.

In the example shown in FIG. 8, a permanent magnet 8 is used as a means for applying a bias magnetic field, but an electromagnet may be used instead. In that case, the bias magnetic field can be arbitrarily determined by varying the current flowing through the coil forming the electromagnet.

FIG. 12 shows another example of the essential parts of the device of the present invention. In this example, upper and lower subcoils 3 and 4 are wound around left and right legs 9A and 9B of a "Japanese"-shaped core 9.
Permanent magnets 10 and 11, which are shown with diagonal lines in the figure, are connected to parts of the legs 9A and 9B. In this case, the polarities of the magnets 10 and 11 are determined so that the magnetic flux is continuous at the outer circumference of the core 9. The legs 9C of the core 9 are connected to each coil 3 and 4.
Coils 3 and 4 are used to bypass the magnetic field φc due to
This is to prevent the magnetic fields from affecting the legs 9B and 9A, respectively.

In this example, coils 3 and 4 are connected to legs 9A and 9.
By moving it relative to B, the magnitude of its inductance value can be controlled.

Effects of the Invention According to this invention, by providing a core for the subcoil and applying a bias magnetic field to the core, it is possible to change the distribution of the deflection magnetic field on the left and right sides of the screen. R
Correction can be made by moving the blue beam B in the same direction on the left and right sides of the screen. Therefore, it is possible to correct the bow-shaped beauty pageant.

[Brief explanation of drawings]

Figure 1 is a diagram to explain the cross pageant.
Figure 2 is a diagram to explain the bow-shaped beauty pageant, Figure 3
The figure shows the structure of the horizontal deflection yoke, Figure 4 shows the connection of the horizontal deflection coil, Figure 5 shows an example of a conventional correction device, and Figures 6 and 7 are for explanation. , FIG. 8 is a diagram showing an example of the main part of this invention device, FIGS. 9 to 11 are diagrams for explaining the same, and FIG. 12 is a diagram showing another example of the main part of this invention device. It is a diagram. 1 and 2 are upper and lower horizontal deflection coils, 3 and 4 are subcoils, 7 and 9 are cores, and 8, 10, and 11 are magnets for applying a bias magnetic field.

Claims (1)

[Claims] 1. A device for correcting misconvergence by using a deflection yoke without using a convergence yoke, which subcoils are respectively connected to upper and lower horizontal saddle-shaped coils connected in parallel, and these subcoils is wound around a core having means for applying a bias magnetic field, and the magnetic field generated by a horizontal deflection current flowing through one subcoil is in the same direction as the direction of the bias magnetic field applied to the core. , the arcuate misconvergence can be corrected by winding each subcoil around the core so that the magnetic field generated by the horizontal deflection current flowing through the other subcoil is in the opposite direction. Convergence correction device.