JPH06119883A - Deflection yoke device - Google Patents

Abstract

PURPOSE:To eliminate a danger where vertically deflected magnetic field leaking from a deflection yoke mounted on a cathode-ray tube, has an adverse effect on the adjacent cathode-ray tube. CONSTITUTION:A pair of correcting coils 3a and 3b are laid at both right and left sides of a deflection yoke 1 having vertical deflection coils 2a and 2b. The coils 3a and 3b are connected to the coils 2a and 2b for generating magnetic field to offset the external leakage component of vertically deflected magnetic field. As a result, only the external leak component of the vertically deflected magnetic field is offset by the magnetic field of the coils 3a and 3B, thereby eliminating a danger where the external leak component interferes with other sections and forms a cause for generating a horizontal fringe noise.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a deflection yoke mounted on a picture tube for generating a horizontal deflection magnetic field and a vertical deflection magnetic field, and a pair of magnetic fields for generating an external leakage component of the vertical deflection magnetic field. The present invention relates to a deflection yoke device including a compensation coil.

[0002]

2. Description of the Related Art A display tube of a desktop personal computer usually uses a picture tube.
When a plurality of such display devices are arranged close to each other as seen in a dealing room of a securities company, extremely low frequency magnetic fields of 5 hertz to 2 kilohertz caused by the vertical deflection magnetic fields interfere with each other to cause a picture of a picture tube. Horizontal lines of dark lines or bright lines are easily mixed in as noise. The horizontal stripes do not move when the frequencies of the interfering extremely low frequency magnetic fields are the same, but when the frequencies are not the same, the horizontal stripes move from the top to the bottom of the screen or from the bottom to the top due to the synchronization shift. Therefore, the quality of the reproduced image is further deteriorated.

[0003]

SUMMARY OF THE INVENTION Therefore, it is an object of the present invention to provide a deflection yoke device which does not cause the horizontal stripes as described above even if the display devices are arranged close to each other.

[0004]

According to the present invention, a pair of compensation coils are arranged on both left and right sides of a deflection yoke having a horizontal deflection coil and a vertical deflection coil. The compensation coil is connected to the vertical deflection coil to generate a magnetic field for canceling external leakage components of the vertical deflection magnetic field.

[0005]

According to this structure, the external leakage component of the vertical deflection magnetic field is canceled by the magnetic field generated by the pair of compensation coils, so that the external leakage component of the vertical deflection magnetic field interferes with others and horizontal stripe noise appears on the screen. The risk of causing is eliminated.

[0006]

The present invention will be described below with reference to the illustrated embodiments. The deflection yoke 1 shown in FIGS. 1 to 3 includes at least a pair of vertical deflection coils 2a and 2b wound in a saddle and a pair of horizontal deflection coils (not shown). Occur. Deflection yoke 1
A pair of compensation coils 3a and 3b are arranged on both left and right sides of the. The pair of vertical deflection coils 2a and 2b and the pair of compensation coils 3a and 3b are connected as shown in FIG. 4, and one pair is provided on the low voltage terminal side of the pair of vertical deflection coils 2a and 2b connected in parallel. A pair of compensation coils 3a and 3b are connected in series. A series connection body of a damping resistor 4 and a capacitor 5 is connected in parallel to the pair of compensation coils 3a and 3b connected in series. The capacitor 5 may be omitted.

The pair of compensation coils 3a and 3b generate a magnetic field for canceling the external leakage component of the vertical deflection magnetic field generated by the vertical deflection coils 2a and 2b. The deflection yoke device in this example is a saddle-saddle type for a 14-inch 90-degree deflection type color picture tube, and a pair of compensation coils 3a and 3b are wound around a rectangular winding frame of 53 mm × 80 mm with 38 turns. The coil center axis is placed parallel to the horizontal axis x.

The deflection yoke structure thus constructed is
Attached to a 14-inch 90-degree deflection type color picture tube, Leaky vertical deflection magnetic field (ELMF) in accordance with MPR-2 defined by the Swedish National Metrology and Testing Council (SWEDAC)
When the (extremely low frequency magnetic field) level was measured, the results plotted with circles in FIG. 5 were obtained. Further, the leakage vertical deflection magnetic field level in the state where the compensation coil is removed is plotted by x in the same figure.

As apparent from the above, by adding a pair of compensation coils, the leakage vertical deflection magnetic field level is 43% (45 nT in absolute value) on the left side of the deflection yoke and 68% (93 nT in absolute value) on the right side. ) It can be seen that it has been reduced. Further, when two display devices mounted with such a 14-inch 90-degree deflection type color picture tube with a deflection yoke device were brought close to each other for display operation, the occurrence of horizontal stripe noise as described above was not observed at all. It was

The present invention is not limited to the above-mentioned embodiment, and it goes without saying that the shape and the number of turns of the compensation coil can be variously selected.

[0011]

As described above, according to the present invention, the vertical deflection magnetic field can be changed by a relatively simple modification in which a pair of compensation coils are arranged on both left and right sides of the deflection yoke and a vertical deflection current is passed through the compensation coils. It is possible to prevent the occurrence of horizontal stripe noise caused by external leakage components.

[Brief description of drawings]

FIG. 1 is a front view of a deflection yoke device embodying the present invention.

FIG. 2 is a plan view of the device.

FIG. 3 is a side view of the device.

FIG. 4 is an electric circuit diagram of a main part of the device.

FIG. 5 is a characteristic diagram in which the leakage vertical deflection magnetic field levels of the same device and a conventional device of the same type are compared.

[Explanation of symbols]

 1 deflection yoke 2a, 2b vertical deflection coil 3a, 3b compensation coil

Claims (1)

[Claims] 1. A pair of compensation coils arranged on both left and right sides of a deflection yoke having a horizontal deflection coil and a vertical deflection coil to generate a magnetic field for canceling an external leakage component of the vertical deflection magnetic field. A deflection yoke device, which is connected to a vertical deflection coil.