JPH01157187A - Conversence correcting device - Google Patents

Abstract

PURPOSE:To cause frame error correction to be suitable over whole screen by providing the plural couples of frame error correcting coils and canceling a correcting over part, which is generated by one correcting coil, with the other correcting coil. CONSTITUTION:A frame error correcting coil 3a, which is wound to a core 2, generates a magnetic field to have a line 5a of magnetic force and a coil 4a generates the magnetic field to have a line 6a of magnetic force. Then, a frame error correcting coil 3b, which is wound to a core 1, generates the magnetic field to have a line 5b of magnetic force and a coil 4b generates the magnetic field to have a line 6b of magnetic force. The core 1 and 2 are provided near the electron gun of a television picture tube and a current in a sawtooth shape wave form, which is synchronized with a vertical deflecting period, is flown to the coils 3a and 4a. Then, conversence dislocation, which is generated with accompanying vertical deflection in the generated magnetic field, is corrected and the coils 3b and 4b are driven by the current in a waveform besides the sawtooth waveform to be synchronized to the vertical deflecting period. Then, the magnetic field of the reverse polarity of the coils 3a and 4a is generated and the conversence dislocation to accompany the correcting over due to the coils 3a and 4a is corrected.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a convergence correction device, and more particularly to a convergence correction device for an in-line electron gun and a color picture tube having a self-convergence type deflection yoke.

2. Description of the Related Art In general, in a color picture tube used in a color television receiver, the electron beams individually emitted from three electron guns are not only focused on the fluorescent surface, but also concentrated on the same hole in the shadow mask ( Convergence) is necessary.

For this reason, in the conventional three-electron gun in-line color picture tube, in order to obtain good concentration of the three electron beams on the fluorescent surface, the vertical deflection magnetic field is barrel type, and the horizontal deflection magnetic field is changed to binction type. A deflection device equipped with a self-convergence type deflection yoke that provides a magnetic field distribution is used.

However, it is well known that in the self-convergence type deflection yoke, a convergence deviation (hereinafter referred to as coma error) d between the center beam G and the side beams R and B due to coma aberration occurs as shown in FIG. In order to correct this coma error in the direction perpendicular to the inner die, as shown in FIG. 22b, 23a, 23b, or a six-pole magnetic field as shown in Figure 8 (A>) or a four-pole magnetic field as shown in Figure 8 (B).
A set of coils for generating a polar magnetic field is arranged near the electron gun. Note that the current flowing through the coil that generates the magnetic field as shown in FIG. 8 was supplied in the form of a sawtooth waveform with a vertical deflection period.

Problems to be Solved by the Invention However, when vertical coma error correction is performed optimally on the upper and lower sides of the screen using a conventional correction device as shown in FIGS. 7 and 8, as shown in FIG. As shown in the figure, the correction becomes excessive in the middle part 26 of the screen between the center part 25 and the upper side part 24 of the screen.

When this is viewed in terms of the relationship between the vertical deflection distance and the amount of overcorrection of the coma error, it becomes a curve as shown in FIG. 10, which causes problems such as deterioration of convergence quality.

The present invention has been made in view of the above points, and an object of the present invention is to provide a convergence correction device that can perform optimal coma error correction over the entire screen.

Means for Solving the Problems The present invention provides at least one pair of in-line color picture tubes equipped with a self-convergence type deflection yoke in the vicinity of the electron gun, in which a sawtooth waveform current synchronized with the vertical deflection period is passed. A first coma error correction coil is provided for correcting convergence deviation caused by deflection, and at least one set is provided near the electron gun and is driven by a current having a waveform other than a sawtooth waveform synchronized with the vertical deflection period. The second coma error correction coil generates a magnetic flux having a polarity opposite to that of the correction coil and corrects a convergence shift caused by over-correction by the first coma error correction coil.

Operation: At least one set of the first coma error correction coils is provided near the electron gun of an in-line color picture tube equipped with a self-convergence type deflection yoke, and a current having a sawtooth waveform synchronized with the vertical deflection period is passed therethrough. The generated magnetic field corrects the convergence shift that occurs with vertical deflection.

Like the first coma error correction coil, at least one set of the second coma error correction coil is provided near the electron gun, and is driven by a current having a waveform other than the sawtooth waveform synchronized with the vertical deflection period. generates a magnetic field of opposite polarity to correct a convergence shift caused by over-correction by the first coma error correction coil.
.

Embodiment FIG. 1 shows a schematic diagram of an embodiment of the present invention. In the figure, 1.
2 represents a core, and 3a, 3b, 4a, 4b represent coils.

Coils 3a and 4a are wound around the core 1, and the coil 3a generates a magnetic field having lines of magnetic force as shown by a solid arrow 5a, and the coil 4a generates a magnetic field having lines of magnetic force as shown by a broken arrow 6a. Further, coils 3b and 4b are wound around the core 2, and the coil 3b generates a magnetic field having lines of magnetic force as shown by a solid arrow 5b, and the coil 4b generates a magnetic field having lines of magnetic force as shown by a broken arrow 6b. The core 1.2 is placed near the electron gun of a television picture tube to form a hexapole magnetic field.

The coils 3a, 3b, 4a, 4b are wired as shown in FIG. In the figure, 7.8 indicates a vertical deflection coil.

A sawtooth waveform current is passed between terminals 9 and 10. Therefore, the magnetic flux generated by the coils 4a and 4b is as shown in Fig. 4(A).
It will look like the one shown below. Further, at both ends of the coils 3a and 3b, at least one pair of diodes D+, 02 connected in parallel with opposite polarities, or at least a pair of Zener diodes D3, D4 connected in series with opposite polarities, are connected in parallel. It is connected.

At this time, the turn-on voltage of the diodes D+, D2 or the Zener diodes D3, D4 is changed to the coil 3a when the electron beam is deflected to approximately the middle part in the vertical deflection direction.
Set to match the voltage across 3b.

In addition, current flows through the coils 3a and 3b with a polarity that generates a magnetic field that increases the coma error, and the coil 4
A and 4b are wired so that current flows with polarity that reduces coma errors.

Therefore, magnetic flux as shown in FIG. 4(B) is generated in the coils 3a, 3b, and the coils 3a, 3b, 4a.

4b, a magnetic flux as shown in FIG. 4(C) is generated.

In this embodiment, the change in the amount of coma error correction with respect to the vertical deflection distance is shown by a solid line 21 in FIG. 5(A) when the coma error correction is set optimally on the upper and lower sides of the screen. Also, the fifth
A broken line 20 in FIG. 2A shows a change in the amount of coma error correction with respect to the vertical deflection distance by the sawtooth wave current, which is set so that the coma error correction is optimal at the upper and lower sides of the screen.

Next, the amount of change in the coma error correction amount in this embodiment with respect to the coma error correction a using the conventional sawtooth wave current is calculated as the fifth
Shown in Figure (B).

In the conventional coma error correction using only the sawtooth wave current, the coma error correction exceeds the area near the middle part 26 of the screen, as shown in FIG. However, in the correction according to this embodiment, compared to the conventional coma error correction using sawtooth wave current,
As shown in FIG. 5(B), the amount of correction is undersized in the middle part 26 of the screen.

Therefore, over-correction of the coma error as shown in FIG. 10 can be canceled, so that misconvergence patterns can be favorably corrected.

FIG. 3 shows a schematic diagram of another embodiment. As shown in FIG. 3, a coil 14a is wound around the core 13, and a coil 14b is wound around the core 12, and a sawtooth waveform current synchronized with the vertical deflection period creates lines of magnetic force as shown, for example, by arrows 15a and 15b. The configuration is such that a magnetic field is generated to correct the convergence shift at the top and bottom sides of the screen, and a coil 18 is installed in the core 17.
A coil 18b is wound around the core 16, and the coil 14a is formed.

By generating a magnetic field having lines of magnetic force as shown by arrows 19a and 19b of opposite polarity to the magnetic field generated by 14b,
It is possible to effectively correct the coma error in the same way as the one shown in FIG.

In the above two embodiments, a coma error correction device using a 6-pole coil was explained, but a device using a 4-pole coil as shown in FIG. 8(B) or a magnetic piece as shown in FIG. 7 may be used. However, misconvergence patterns can be effectively corrected.

Further, since the correction device of this embodiment does not need to obtain a complicated correction waveform and does not require an electric circuit for this purpose, optimal coma error correction can be performed at low cost.

Furthermore, although the above two embodiments have been described in which one set each of the first coma error correction coil and the second coma error correction coil are provided, it is also possible to provide a plurality of each of them for correction.

Effects of the Invention As described above, according to the present invention, at least two sets of frame error correction coils are provided, and the over-correction caused by one correction coil is canceled by the other correction coil. It has the advantage of being able to perform corrections and improving the screen quality of television picture tubes.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram of an embodiment of the present invention, Fig. 2 is a wiring diagram of an embodiment of the invention, Fig. 3 is a diagram for explaining another embodiment of the invention, and Fig. 4 is a diagram for explaining another embodiment of the invention. A corrected magnetic flux waveform diagram obtained by a correction device according to an embodiment of the present invention, FIG. 5 is a diagram showing an over amount of coma error correction with respect to a vertical deflection distance according to an embodiment of the present invention, and FIG. 6 is a diagram showing convergence deviation due to coma aberration. Figures 7 and 8 are diagrams showing an example of a convergence correction v device, Figure 9 is a diagram showing a convergence shift pattern caused by correction of only a sawtooth wave current, and Figure 10 is a diagram showing a convergence shift pattern caused by correction of only a sawtooth wave current. FIG. 7 is a diagram illustrating over-correction of the common error due to correction of only current. 1.2=-17,3a, 3b・ml/L/,
4a. 4b... Coil, 6a, 6b... Lines of magnetic force, 7...
Vertical deflection coil, 8... Vertical deflection coil, D+, D
2...Diode, D3, D4... Zener diode. Figure 1 Figure 4 Figure 2 Figure 3 Figure 5 Figure 6 Figure 7-22b Figure 8 (A) (B)

Claims (1)

[Claims] At least one set is provided near the electron gun of an in-line color picture tube equipped with a self-convergence type deflection yoke, and a current having a sawtooth waveform synchronized with the vertical deflection period,
a first coma error correction coil for correcting a convergence shift caused by vertical deflection; A convergence correction device comprising: a second coma error correction coil for correcting a convergence shift due to over-correction by the coma error correction coil.