JPH022261B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a deflection yoke for a color cathode ray tube having an in-line electron gun.

Generally, the magnetic field generated by the deflection coil has a barrel-shaped magnetic field distribution at its front and rear end portions, that is, on the screen side and the neck portion side. When the magnetic field in the front part (on the screen side) of the vertical deflection coil tends to be barrel-shaped, side pink distortion is produced on the screen, as is well known.

Traditionally, side pink coupling distortion has been improved by installing a correction circuit and changing the deflection current, but recently a toroidal vertical deflection coil has been divided and wound around the core, and the winding distribution of the deflection coil has been improved. A side pinless type deflection yoke has been developed that corrects side pink coupling distortion by changing the angle at the front and rear ends of the core.

However, the side pinless type deflection yoke described above requires dividing the toroidal coil wound around the core and changing the winding distribution at the front and rear ends of the core, making the winding work complicated and inefficient. There were flaws.

For this reason, the front (screen side) of the deflection yoke
By installing a magnetic field correction means having a magnetic field receiving part and a magnetic field forming part, the magnetic field distribution in the front part of the deflection yoke can be made uniform without making the winding distribution of the vertical deflection coil special. A so-called arm-type deflection yoke that corrects side pink tension distortion has recently been developed and is being put into practical use.

However, the arm-type deflection yoke has the drawback that misconvergence occurs in the vertical direction at the left and right measurement points on the X-axis of the screen.

The present invention aims to provide an arm-type deflection yoke that corrects the vertical misconvergence at the left and right measurement points on the X-axis of the screen.Please refer to the attached drawings for embodiments of the present invention below. This will be explained in detail.

As mentioned above, when the arm is attached to the magnetic field correction means, so-called arm-less deflection yoke, the vertical misconvergence (Xv) at the left and right measurement points on the X-axis of the screen is based on the red color (R). blue color (B) is generated in the counterclockwise direction. Furthermore, when vertical scanning is changed from forward scanning to reverse scanning, blue color is generated clockwise in Xv with red as the reference. The inventor conducted various experiments to find out why Xv changes in this way, and found the cause. That is, it was found that when the arm is attached to the deflection yoke, Xv changes due to the residual magnetism that appears in the hysteresis characteristic caused by the material of the arm (usually a silicon steel plate).

FIG. 1 schematically shows the residual magnetism caused by the arm during forward scanning. In the figure, 10 is the arm (magnetic field correction means), 11 is a cross section of an enlarged part of the color cathode ray tube, B, G, and R are blue; Green and red beams are shown respectively. The residual magnetism caused by the arm 10 is distributed as shown by the arrows in the figure, and is not uniform on the X-axis of the screen. As shown in FIG. The distribution is such that the absolute value decreases as one goes in the direction (direction). The direction of the magnetic field is always to the left during forward scanning. Therefore, for example, if the beam is +
When deflected in the X direction, blue (B) is affected by residual magnetism more than red (R), and conversely, in the -X direction, red is affected more. That is, when deflecting to the right, blue is deflected more in the +Y direction than red, and when deflecting to the left, the opposite is true. As a result, Xv changes counterclockwise.

The present invention has been made with attention to the above point, and is designed to correct Xv by making the upper inductance value and the lower inductance value of the horizontal deflection coil unbalanced.

Hereinafter, one embodiment of the deflection yoke of the present invention will be described in detail with reference to the drawings. In Figures 3 and 4,
Reference numeral 1 designates a deflection yoke, which includes a pair of upper and lower horizontal deflection coils 2a, 2b wound in a saddle shape, and a coil bobbin 3 on which the horizontal deflection coils 2a, 2b are arranged inside.
and a core 4 arranged on the outer surface of the coil bobbin 3.
and a pair of vertical deflection coils 5a and 5b wound toroidally around the outer periphery of the core 4.
At the front of the deflection yoke 1, magnetic field correction means (arms) 6, 6 are arranged. As shown in FIG. 5, the magnetic field correction means 6, 6 respectively include a magnetic field receiving part 6a which is arranged near the core 4 and the vertical deflection coils 5a, 5b and receives the leakage magnetic field, and a magnetic field receiving part 6.
The coil bobbin 3 has a magnetic field forming part 6b that forms a correction magnetic field by the magnetic field received from the coil bobbin 3, and is fixed and attached along the outer periphery of the front enlarged part 3a of the coil bobbin 3 symmetrically with respect to the Y axis.

In the deflection yoke having such a configuration, when the inductance value of the upper horizontal deflection coil 2a is made smaller than the inductance value of the lower horizontal deflection coil 2b, the horizontal deflection magnetic field is such that the current flowing through the upper coil 2a is larger than that flowing through the lower coil 2b. Since the current is larger than the current flowing through the current, the distribution becomes somewhat like a figure-of-eight as shown in FIG. When deflected to the left and right under such a horizontal deflection field, a horizontal component H' (which deflects the beam in the vertical direction) is generated as shown in the horizontal deflection field, and Xv changes clockwise, This is caused by the residual magnetism of the magnetic field correction means 6, 6.
Can cancel Xv. According to experiments conducted by the present inventor, it has been confirmed that the difference in inductance values between the upper and lower horizontal deflection coils may be small, and that misconvergence in the vertical direction due to residual magnetism of the magnetic field correction means can be sufficiently corrected.

In addition, in one embodiment of the deflection yoke of the present invention,
Although the vertical deflection coil has a toroidal winding shape around the core, it may be wound around the core in a hollow shape like the horizontal deflection coil.

As described above, according to the present invention, since the inductance value of the lower coil of the horizontal deflection coil is only made slightly larger than the inductance value of the upper coil, sensitivity is not decreased and reliability is high. Furthermore, since the difference in inductance value may be small, it is sufficient to select and incorporate the coils. Therefore, there are many excellent advantages such as the fact that no additional parts are required and Xv can be corrected at low cost.

As described above, the present invention provides an arm-type deflection yoke that can reliably eliminate vertical misconvergence at the left and right measurement points on the X-axis of the screen with an extremely simple configuration.
For example, when applied to an in-line color picture tube, the effect is remarkable.

[Brief explanation of drawings]

Fig. 1 is a schematic diagram for explaining the influence of residual magnetism in the arm of a conventional arm-type deflection yoke, Fig. 2 is a diagram showing the distribution of residual magnetism in the arm of Fig. 1, and Fig. 3 is a diagram showing the present invention. FIG. 4 is a side view of one embodiment of the deflection yoke, FIG. 4 is a front view, FIG. 5 is a configuration diagram of the magnetic field correction means (arm), and FIG. 6 is a diagram showing the magnetic field distribution due to the horizontal deflection coil of the deflection yoke of the present invention. It is a diagram. DESCRIPTION OF SYMBOLS 1... Deflection yoke, 2a... Upper horizontal deflection coil, 2b... Lower horizontal deflection coil, 3... Coil bobbin, 4... Core, 5a, 5b... Vertical deflection coil, 6... Magnetic field correction means, 6a ...Magnetic field receiving part, 6b...Magnetic field forming part, H'...Horizontal component of horizontal deflection magnetic field.

Claims (1)

[Claims] 1. A horizontal deflection coil having a horn shape, a coil bobbin in which the coil is disposed, a core disposed on the outer surface of the coil bobbin, and a vertical deflection coil wound around the core, the core and the vertical deflection coil The side pink cushioning distortion is corrected by a magnetic field correction means having a magnetic field receiving part disposed near the magnetic field receiving part to receive a leakage magnetic field, and a magnetic field forming part forming a correction magnetic field by the magnetic field received from the magnetic field receiving part. In the deflection yoke, the inductance value of the lower coil of the horizontal deflection coil is made larger than the inductance value of the upper coil, and vertical misconvergence at the left and right measurement points on the screen X axis is corrected. A deflection yoke characterized by: