JPH02148543A - Cathode ray tube display - Google Patents

Abstract

PURPOSE:To eliminate bad electromagnetic effects given to an electronic device installed close to the title device by disposing offset coils perpendicularly to a two-pole leaking magnetic flux close to a starting point of the magnetic flux, and sending a perpendicular deflection current to the coils. CONSTITUTION:A pair of a right and a left offset coil 10 are held at two points of a head part side 12a and a tail part side 12b of a separator 12 forming part of a deflection yoke 3. The offset coils 10 are disposed at the right and left respectively along an axis 7 out of a circular core 4, and perpendicular deflection current is sent to the coils 10 in a predetermined direction, so a magnetic flux 11 is produced by the coils 10 to offset a harmful magnetic flux 8. By selecting a turn number of the coils 10 and the perpendicular deflection current properly, a leak magnetic flux can be eliminated to be nothing around a casing of a cathode ray tube display.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a cathode ray tube display device, and more specifically, the present invention relates to a cathode ray tube display device. The present invention relates to a cathode ray tube display device including a deflection yoke having a deflection coil.

[Prior Art] FIG. 7 shows a conventional cathode ray tube display device, in which a deflection yoke (3) is attached to the neck of a cathode ray tube (1) placed inside a housing (2). FIG. 8 is a sectional view of the deflection yoke (3), which generally has an annular core (4
) consists of a vertical deflection winding (5) wound in a toroidal shape and a horizontal deflection winding (6) wound in a saddle shape.

Connect the toroidal vertical deflection winding (5) to the outer winding (5a).
and the inner winding (5b), and consider the magnetic flux generated by each.

Deflection current (-, generally 40
When a low frequency sawtooth wave (about 8011z) is applied, the magnetic flux within the core (9) is divided near the X-X axis into an effective vertical deflection magnetic flux (7) that contributes to vertical deflection and an invalid vertical magnetic flux that does not contribute to deflection. (8) Divided into.

[Problems to be Solved by the Invention] In the conventional cathode ray tube display device as described above, when viewed macroscopically, the ineffective vertical magnetic flux (8) is N on the X-X axis, as shown in FIG. Forming a bipolar magnetic field with an S pole,
This had an adverse electromagnetic effect on electronic equipment (3) installed near the cathode ray tube display device.

Conventionally, as a countermeasure against this problem, a method has been taken in which the inner surface of the casing (2) is lined with a magnetic material, but this method has the drawback of increasing costs. Alternatively, there were layout constraints, such as increasing the distance between the damaged electronic equipment and the cathode ray tube display device, or installing a magnetic wall between them.

The present invention was made to solve the above problems, and an object of the present invention is to provide a cathode ray tube display device that does not have an adverse electromagnetic effect on electronic equipment installed nearby.

[Means for Solving the Problems] A cathode ray tube display device according to the present invention includes a cancellation coil arranged perpendicularly to the magnetic flux near the starting point of the leakage magnetic flux of the two poles, and a vertical deflection current applied to the coil. I decided to pass.

[Function] In this invention, the magnetic flux generated by the canceling coil causes
Harmful leakage magnetic flux is canceled.

[Example] An example of the present invention will be described below with reference to FIGS. 1 to 3. However, in these drawings, Figures 7 to 9
The same reference numerals in the figures indicate the same parts and the same functions.

In Fig. 2, a pair of left and right cancellation coils (1o) are
It is held at two points on the head side (12a) and foot side (12b) of a separator (12) that forms part of the deflection yoke (3). Further, the cancellation coil (10) is housed in a trough-shaped cancellation coil storage molded member (13), as shown in FIG.

Next, the operation will be explained. Figure 1 shows the cancellation coil (1
0), in which canceling coils (10) are arranged, one each on the left and right, on the starting point and ending point of the leakage magnetic flux, that is, on the X-x axis outside the annular core (4), When a vertical deflection current is passed through the coil (10) in the direction shown by (■, ・■) in the figure, the cancellation coil (10) flows in the direction shown in the figure.
10) generates magnetic flux (11), causing harmful magnetic flux (8)
cancel out. The number of turns of the cancellation coil (10) and the above-mentioned vertical deflection current can be adjusted accordingly. Note that inside the annular core (4), most of the magnetic flux due to the cancellation coil (10) passes through the core (4) and does not cancel the effective magnetic flux (7), so the decrease in deflection sensitivity can be ignored. sell.

Figure 4 shows examples of the shapes of the cancellation coils (lO), in which (a) is rectangular, (b) is trapezoidal, (c) is circular,
The figure (d) shows a saddle shape, and various other modifications are possible.

In Fig. 2, the cancellation coil (10) is attached to the deflection yoke (3), but in Fig. 5, the cancellation coil (10) is attached to the casing (2).
) is shown. Figure 6(a)
, (b) and (c) respectively show various ways of connecting the vertical deflection winding (5) and the cancellation coil (10).

In the above embodiment, the vertical deflection winding is of a toroidal type and a low frequency current flows through the winding, but the horizontal deflection winding is of a toroidal type and a low frequency current flows through it. The arrangement of the cancellation coil is
The same effect can be obtained by arranging it at a position rotated by 90 degrees from that of the embodiment described above.

Furthermore, in the above embodiment, the case where a low frequency current flows through a toroidal winding was explained, but it is easy to understand that a similar effect can be obtained when a low frequency current flows through a saddle winding. can.

[Effects of the Invention] As described above, according to the present invention, by providing a coil that cancels the ineffective leakage magnetic flux created by the deflection winding through which a low frequency current flows, other electronic devices installed nearby Since the negative electromagnetic influence on the magnetic field can be removed, the magnetic shielding measures conventionally employed are no longer necessary, a low-cost device can be obtained, and furthermore, there are fewer restrictions on equipment placement.

[Brief explanation of the drawing]

Figures 1 to 3 show an embodiment of the present invention, with Figure 1 being a schematic front sectional view of main parts for explaining the operation, Figure 2 being a side sectional view, and Figure 3 being a partial cross sectional view. It is a diagram. FIG. 4 is a schematic diagram of a modification of the cancellation coil used in the present invention;
5 is a side sectional view of another embodiment, FIG. 6 is a connection diagram between the low frequency winding and the cancellation coil in the present invention, FIG. 7 is a side sectional view of a conventional cathode ray tube display device, and FIG. 8 is a side sectional view of another embodiment. The figure is a schematic front sectional view of the main part showing the magnetic flux distribution in the one in Figure 7,
FIG. 9 is a visual view of FIG. 8. (3)... Deflection yoke, (4)... Annular core, (5)...
・Vertical deflection winding, (6)...Horizontal deflection winding, (8)...
Ineffective vertical magnetic flux (leakage magnetic flux), (10)...cancellation coil. In each figure, the same reference numerals indicate the same or corresponding parts. Broom 4 Figure 7

Claims (1)

[Claims] In a cathode ray tube display device including a deflection yoke that is wound around an annular core and provided with a deflection winding through which a low-frequency sawtooth current flows, there is provided a path of leakage magnetic flux leaking to the outside of the annular core. 1. A cathode ray tube display device, comprising a cancellation coil installed perpendicularly to the magnetic field, through which a deflection current is applied to cancel the leakage magnetic flux.