JPH01154441A - Deflection yoke device - Google Patents

Abstract

PURPOSE:To prevent a reduction in life and an increase in weight due to an increase in temperature in internal electronic circuits by winding a cancel coil in the circumferential direction of a circular core. CONSTITUTION:A device is equipped with a circular core 2 approximately in a cylindrical form, which is fixed on the narrow diameter section of a cathode ray tube 1, with horizontal coils 3 and 4 provided along the inner circumferential surface of the aforesaid core 2, with a vertical coil wound by the circular core 2 and with concel coils 21 and 22 wound in the circumferential direction of the circular core 2. And horizontal deflection current is applied to the cencel coils 21 and 22 in such a way that a magnetic field induced from the front side of a deflection yoke is cancelled or reduced. This constitution thereby can prevent a reduction in life and an increase in weight due to an increase in temperature in internal electronic circuits.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to an improvement in a deflection yoke device for electromagnetically deflecting a high-energy electron beam in a cathode ray tube (hereinafter referred to as CRT). It is something.

[Conventional technology]

Figure 4 shows, for example, "rNHK color television reception technology" P19
4 (published by Japan Broadcasting Corporation on April 10, 1986). In the figure, 1 is a CRT, and 2 is a narrow diameter portion 1a of the CRTl (near the electron gun). A substantially cylindrical annular core (toroidal core) attached to the section, 3.4 horizontal coils disposed facing each other in a substantially horizontal direction along the inner peripheral surface of the annular core 2, 5.6
is wound around the annular core 2 to form the horizontal coil 3.
The horizontal coils 3 and 4 and the vertical coils 5 and 6 constitute a deflection yoke 7, which is a vertical coil that generates a magnetic flux in a direction perpendicular to the magnetic flux of 4°. In addition, in Fig. 5, the vertical coil 5.6 driven at a frequency around 60 Hz is regulated in the magnetic flux range (Magnetic field No. 1se) of the West German electromagnetic wave unnecessary radiation control standard VDEO871 from 10 kHz, and the range is regulated from 10 kHz. Since the level of harmonics does not reach the limit, they will be omitted to simplify the explanation.

Next, the operation will be explained.

In principle, the horizontal coils 3 and 4 generate horizontal magnetic flux, and the vertical coils 5 and 6 generate vertical magnetic flux. For this reason, these two
A magnetic field having directional magnetic flux is formed around the annular core 2. In addition, the above horizontal magnetic flux and perpendicular (one flux is the horizontal coil 3
．． The strength of the magnetic field changes depending on the amount of current flowing through the vertical coils 4 and 5.6. Then, due to this magnetic field, the electron beam passing through the narrow diameter portion la of the CRTI inserted through the central portion of the annular core 2 is deflected to form an image on the CRTl. That is, in FIG. 5, when currents as shown by symbols 8 and 9 flow through the horizontal coils 3 and 4 of the deflection yoke 7, a horizontal magnetic flux shown by the solid arrow is generated, and as shown by the symbol 10. deflect.

By the way, magnetic fluxes of 11.12° and 13.14 are generated at the front ends 3a, 4a and the rear ends 3b, 4b of the horizontal coil 3.4 at the locations indicated by reference numeral 8.9 where the current direction changes, and these magnetic fields are The mechanism generates unnecessary radiated magnetic flux 15,16 that does not particularly contribute to deflection. The level of this unnecessary radiated magnetic flux 15.16 is due to the large opening on the front side of the deflection yoke 7 and the fact that the line HM of magnetic flux 11.12 is longer than the 1X flux 13.14. Figure 6 shows the magnetic flux when measuring a display monitor DM or television equipped with this conventional deflection/yielding device using the measurement method of the West German unnecessary radiation control standard VDEO877. The front magnetic fluxes 17, 18, and 19 are looped on the ground because the magnetic permeability of the ground is greater than that of the atmosphere.

[Problem that the invention seeks to solve]

Since the conventional deflection yoke device is configured as described above, the magnetic path is made of a material with high magnetic permeability such as an iron plate or permalloy in order to prevent the influence of the unnecessary radiated magnetic flux 15 generated from the deflection yoke 7. Since the CRTI and deflection yoke 7, including the electronic circuits, must be short-circuited and surrounded by a steel plate, the temperature of the internal electronic circuits increases, resulting in reduced service life and increased weight, resulting in deterioration of service. There was a point.

The present invention was made to solve the above-mentioned problems, and aims to provide a deflection yoke device that does not cause a decrease in life or an increase in weight due to temperature rise of internal electronic circuits.

[Means for solving problems]

The deflection yoke device according to the present invention includes a substantially cylindrical annular core attached to a narrow diameter portion of a cathode ray tube, a horizontal coil provided along the inner peripheral surface of this annular core, and a vertical coil wound around the annular core. It includes a coil and a canceling coil wound around the annular core.

[Effect]

The tendency yoke device according to the present invention cancels or reduces the magnetic field generated from the front side of the deflection yoke by passing a horizontal deflection current through a cancellation coil wound in the circumferential direction of an annular core.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. 1st
The figure is a sectional view showing one embodiment of the present invention, and the same or equivalent parts in FIG. 1 as in FIG. 4 are given the same reference numerals, and redundant explanation will be omitted.

In FIG. 1, reference numerals 21 and 22 denote canceling coils wound along the circumferential direction of the annular core 2, and the canceling coils 21 and 22 are the unnecessary radiated magnetic flux 16 generated from the front side of the upper horizontal coil 3 of the deflection yoke 7. This is to reduce the size of.

Further, the canceling coils 21 and 22 include horizontal coils 3.
The waveform is the same or similar to the horizontal deflection current flowing through 4, and the frequency is n.
A current twice as large (n is about 1 to 5) is applied.

Next, the operation will be explained.

In FIG. 2, when a current as indicated by reference numeral 8.9 is passed through the horizontal coil 3.4 of the deflection yoke 7, a horizontal magnetic flux I as indicated by the solid arrow is generated. In addition, when a horizontal deflection current is passed through the canceling coil 21.22, the magnetic flux 23.2
4 occurs. Therefore, the front ends 3a of the horizontal coils 3, 4,
4a and rear ends 3b, 4b, respectively, magnetic fluxes 25, 26, ., generated at locations where the current direction changes, indicated by reference numeral 8.9.
27 and 28 are influenced by the magnetic fluxes 23 and 24 of the canceling coils 21 and 22, and the magnetic flux 26 is generated stronger than the magnetic flux 25, and the magnetic flux 27 is stronger than the magnetic flux 28, and these magnetic field generation mechanisms affect the deflection. The unnecessary radiated magnetic flux 15,16 which does not particularly contribute is curved as shown in FIG.

Display monitor DM with built-in deflection yoke device
Or use the West German unnecessary radiation control standard VDEO for televisions.
FIG. 3 shows the magnetic field measured by the No. 877 measurement method. The front magnetic fluxes 17, 18, and 19 of the deflection yoke 7 are strongly curved toward the ground, and are no longer detected by the loop antenna EMI for measuring unnecessary radiation. Further, although the rear magnetic flux of the deflection yoke 7 curves toward the air, it is originally a small magnetic flux and does not become a source of interference.

In the above embodiment, the horizontal deflection current is passed through the canceling coils 21 and 22, but the horizontal deflection current n
When a similar waveform current with twice the frequency is passed, it is possible to strongly cancel n times the unnecessary radiation component.

〔Effect of the invention〕

As described above, according to the present invention, since the deflection yoke device is constructed by winding the canceling coil around the annular core, the unnecessary radiated magnetic flux on the front side of the horizontal coil can be curved toward the ground side, and in particular, the magnetic shield without using materials that cause This has the effect of providing an inexpensive device that can take measures against unnecessary radiation and that does not cause a decrease in life or an increase in weight due to temperature rises in internal electronic circuits.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a deflection yoke device according to an embodiment of the present invention, FIG. 2 is a conceptual diagram of the deflection yoke device for explaining the operation of FIG. 1, and FIG. 3 is a deflection yoke device of the present invention. Fig. 4 is a partially cutaway side view showing an example of a conventional deflection yoke device, and Fig. 5 is for explaining the operation of Fig. 4. FIG. 6 is a side view showing the magnetic flux distribution when unnecessary radiated magnetic flux is measured using a conventional deflection yoke device. ■ is a cathode ray tube (CRT), 2 is an annular core, 3°4 is a horizontal coil, 5 and 6 are vertical coils, and 21.22 is a canceling coil. Note that the same reference numerals in the figures indicate the same or corresponding parts. Relaxation 1 is 2: Annular core 3.4: Flat carp to 7) and 21.22: Can t) Rec/1) and 22 3 Figures 5 and 6: Vertical carp 1 and 5 Figure 6

Claims (1)

[Claims] A deflection yoke device comprising a substantially cylindrical annular core attached to a narrow diameter portion of a cathode ray tube, a horizontal coil provided along the inner peripheral surface of the annular core, and a vertical coil wound around the annular core. A deflection yoke device characterized in that a canceling coil is wound around the annular core.