JPH04237934A - Deflecting york - Google Patents

Abstract

PURPOSE:To enable correction of misconvergence resulting from an axial drift of a convergence characteristic by regulating the quantity of saw-tooth current of a horizontal deflection period which flows through a correction coil by means of a change in the inductance of any one among a first coil to a fourth coil without giving any effect on raster deflection. CONSTITUTION:A convergence correction coil 1 is installed on the side of a deflecting yoke 27, and the quantity of saw-tooth current of a horizontal deflection period which flows through this correction coil 1 is adjusted by a change in inductance of a first coil to a fourth coil 4, 5, 6, 7 so that misconvergence due to an axial drift of convergence characteristic is corrected.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a deflection yoke used in color cathode ray tube displays and the like.

0002

2. Description of the Related Art Before explaining the structure of a conventional deflection yoke, the structure of an in-line color cathode ray tube will first be explained based on FIG. In the figure, 20 is a panel, 21 is a funnel, and 22 is a neck. 23 is a screen in which phosphor dots or stripes of three colors red, green, and blue are arranged regularly on the inner surface of the panel 20; 24 is arranged close to and opposite to the screen 23, and has an electron beam on its main surface; A shadow mask having a passage hole 25, 26 is an in-line electron gun, and three electron beams "R
ED” 28r, “GREEN” 28g, “BLUE” 2
8b and are arranged in a straight line inside the neck 22. 27 is the above funnel 21
This is a deflection yoke provided on the outer wall of the cone portion of the yoke.

In the in-line type electron gun 26, a non-uniform magnetic field is generated by the deflection yoke 27, so that only the combination of the color cathode ray tube 30 and the deflection yoke 27 can generate a non-uniform magnetic field without using any circuit correction means. It is possible to achieve so-called self-convergence, which makes the three electron beams 28r, 28g, and 28b substantially coincident over the entire screen, and the current mainstream method for in-line color cathode ray tubes is the above-mentioned self-convergence method. It also corrects raster distortion at the top and bottom of the screen at the same time.

Next, the principle of self-convergence using a deflection yoke will be explained. Normally, a deflection yoke is formed by two coils, a horizontal deflection coil and a vertical deflection coil, but if the magnetic field distributions generated by both coils are uniform, the convergence characteristics on the screen will be as shown in Figure 10. Therefore, it is not possible to match the three electron beams on the screen.

Therefore, as shown in FIG. 11, by setting the horizontal deflection magnetic field 13 by the horizontal deflection coil 11 to a pin magnetic field and the vertical deflection magnetic field 14 by the vertical deflection coil 12 to a barrel magnetic field, the deflection for the three electron beams is changed. A difference in force occurs, which makes it possible to align the three electron beams on the screen.

When using this method, if variations occur in the three electron guns, horizontal deflection coils, and vertical deflection coils due to manufacturing errors in the cathode ray tube or deflection yoke, the center of the orbit of the electron beam and the deflection magnetic field Shift to the central axis of the distribution (
(hereinafter referred to as axis misalignment) may occur, and convergence on the screen may be disturbed.

FIG. 12 shows an example of axis deviation. FIG. 12(a) shows the convergence characteristic when the horizontal deflection magnetic field is vertically shifted from the center of the orbit of the electron beam, and FIG. (c) shows the convergence characteristics when the horizontal deflection magnetic field is shifted in the horizontal direction with respect to the orbit center of the electron beam. d) is the convergence characteristic when the vertical deflection magnetic field is shifted upward with respect to the orbit center of the electron beam.

FIG. 13 shows a conventionally employed method for correcting the above-mentioned axis deviation. When setting the deflection yoke 27 to the in-line color cathode ray tube 30 having the structure shown in FIG. Axial misalignment is corrected by adjusting the axial position of the magnetic field.

[0009]

According to the above-mentioned conventional deflection yoke, when the deflection yoke is configured to be slightly moved vertically and horizontally to correct axis deviation, raster distortion on the screen becomes worse. This is because by moving the deflection yoke using the tightening band on the neck side of the deflection yoke as a fulcrum, the screen side of the deflection yoke moves significantly, and the magnetic field on the screen side of the deflection yoke is larger than the magnetic field on the neck side. This is due to the high degree of influence that raster distortion has on the characteristics.

The present invention has been made to solve the above-mentioned problems, and provides a deflection yoke that can correct misconvergence due to axis deviation of convergence characteristics without particularly affecting raster distortion. The purpose is to

[0011]

[Means for Solving the Problems] The deflection yoke according to the present invention provides a convergence correction coil on the deflection yoke side, and by passing a sawtooth current with a horizontal deflection period through the correction coil, misconvergence due to axis deviation of the convergence characteristic can be corrected. The present invention is characterized in that it is configured to correct.

0012

According to the present invention, the lateral balance of the horizontal deflection magnetic field can be adjusted by the magnetic field generated by the convergence correction coil, so that misconvergence due to axis deviation of the convergence characteristic can be corrected. Also,
Since the convergence correction coil is installed closer to the neck than the center of the deflection yoke, it is possible to correct convergence with almost no effect on raster distortion.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is an external view of a deflection yoke according to an embodiment of the present invention, and FIG. 2 is a circuit diagram of the horizontal deflection system of the same deflection yoke 27. In both figures, 1 is a convergence correction coil, and 2 is a convergence correction coil 1. A screw core type differential coil adjusts the amount of current flowing, and 3 is a horizontal deflection coil. 4, 5, 6, and 7 are first to fourth coils for adjusting the current flowing through the convergence correction coil 1, and the first and second coils 4, 5 and the third and fourth coils 6, 7 are connected in series, and the convergence correction coil 1 is connected to their connection point, and the series connection line of the first and second coils 4 and 5 and the third and fourth coils 6, 7 series connection lines are connected in parallel, and the parallel connection lines are connected in series to the horizontal deflection coil 3. In addition, 11 in FIG. 1 is a vertical deflection coil, and 15 is a core.

3 to 5 show the structure of the differential coil 2, in which 8 is a cylindrical bobbin having two winding portions on the outside and a screw hole inside, and 9 is this cylindrical bobbin. The screw core inserted into the hollow part of 8 is used to connect the cylindrical bobbin 8.
The first and fourth coils 4, 7 are wound on one of the two winding parts, and the second and third coils 5, 6 are wound on the other, and the screw core 9 is wound by rotation. It is configured to move in its axial direction.

Next, the operation of the above configuration will be explained. First, the first to fourth coils 4, 5, 6 of the differential coil 2
, 7 have the same inductance, that is, the screw core 9
is at the center of the bobbin 8, no current flows through the convergence correction coil 1.

Next, when the screw core 9 is moved in the axial direction from the center of the bobbin 8, for example, when it is moved to the side where the coils 4 and 7 are wound, the inductance of the coils 4 and 7 is equal to that of the other coil. It becomes larger than the inductance of the coils 5 and 6. In this case, the horizontal deflection current is
, 6 becomes large. At this time, a sawtooth current as shown in FIG. 6 flows through the convergence correction coil 1.

Furthermore, when the screw core 9 is moved to the side where the coils 5 and 6 are wound, the inductance of the coils 5 and 6 becomes larger than the inductance of the coils 4 and 7. In this case, the amount of horizontal deflection current flowing through the coils 4, 1, and 7 increases, and at this time, a sawtooth current as shown in FIG. 7 flows through the convergence correction coil 1. That is, by adjusting the position of the screw core 9, the direction of the sawtooth flowing through the convergence correction coil 1 can be changed.

Next, the effect of the magnetic field when a sawtooth current flows through the convergence correction coil 1 will be explained. The convergence correction coil 1 is installed on the neck side of the deflection yoke 27, and is wound around the left and right U-shaped cores. When a sawtooth radio wave as shown in FIG. 6 flows through this convergence correction coil 1, the magnetic field 10 generated by this coil 1 becomes as shown in FIG.

FIG. 8A shows a case where a current flows in the positive direction, and acts to widen the distance between the side beams on both sides of the three electron beams. FIG. 8B shows a case where a current flows in the negative direction, and acts to narrow the distance between the side beams. This effect is synchronized with the horizontal deflection, so it becomes the effect shown in Fig. 8(A) on either the left or right side of the screen.
On the other hand, the effect is as shown in FIG. 8(B). Furthermore, when the waveform of the sawtooth current is as shown in FIG. 7, the directions of action on the left and right sides of the screen are reversed. That is, by adjusting the position of the screw core 9, it is possible to correct the misconvergence caused by the axis deviation of the convergence characteristic shown in FIG. 12(b). Also,
Since such adjustment is performed closer to the neck than the center of the deflection yoke 27, it hardly affects raster distortion.

[0020]

As described above, according to the present invention, the axis misalignment between the deflection yoke and the cathode ray tube can be corrected without worsening raster distortion by simply adjusting the inductance of the coil using a screw core. can be solved and high-quality convergence characteristics can be obtained.

[Brief explanation of the drawing]

FIG. 1 is an external view of a deflection yoke showing an embodiment of the present invention.

FIG. 2 is a circuit diagram of a horizontal deflection system of the deflection yoke in FIG. 1;

FIG. 3 is a front view of main parts.

FIG. 4 is a side view of FIG. 3;

FIG. 5 is a cross-sectional view of FIG. 3;

FIG. 6 is a waveform diagram of a current flowing through a convergence correction coil.

FIG. 7 is a waveform diagram of a current flowing through a convergence correction coil.

FIG. 8 is an explanatory diagram of the state of the magnetic field generated from the convergence correction coil and its effect.

FIG. 9 is a partially cutaway perspective view of an in-line color cathode ray tube.

FIG. 10 shows a misconvergence pattern on the screen when a deflection yoke with a uniform magnetic field is used.

FIG. 11 is a magnetic field distribution diagram showing a horizontal deflection pin magnetic field and a vertical deflection barrel magnetic field.

FIG. 12 is an explanatory diagram illustrating axis deviation of convergence characteristics.

FIG. 13 is a side view showing how a conventional deflection yoke is attached.

[Explanation of symbols]

1 Convergence correction coil 2 Differential coil 3 Horizontal deflection coil 4, 5, 6, 7 Convergence correction current adjustment coil 11 Vertical deflection coil 15 Core

Claims (1)

[Claims] 1. A vertical deflection coil, a horizontal deflection coil, and first, second, third, and fourth coils for passing a horizontal periodic sawtooth current, the first and second coils and the third
and a fourth coil are connected in series, and a convergence correction coil is connected to the connection point thereof, and the series connection line of the first and second coils and the series connection line of the third and fourth coils are connected in parallel. In a deflection yoke formed by connecting the parallel connection line to the horizontal deflection coil in series, the amount of current flowing through the convergence correction coil is adjusted by changing the inductance of the first to fourth coils. A deflection yoke characterized by comprising: