JPH0461733A - Deflection coil - Google Patents

Abstract

PURPOSE:To provide a magnetic field distribution which is not obtainable by usual coiling method, by allowing a plurality of coil parts to generate a specific deflection magnetic field for deflection of a beam, dividing the coil parts into No.1 and No.2 region, and equipping each region with parts where the current directions become opposite to one another. CONSTITUTION:If a part is formed where one turn of coiling is completed only within one of the regions as shown by Point A to B and Points C to D by way of example, a current direction iR can be obtained in each region, which is opposite to the normal current direction iF in the case one turn is wound across from No.1 to No.2 region. This does not require reversal with the coiling direction inverted. Thereby a magnetic field distribution becomes obtainable, which has been difficult according to the conventional techniques, and the degree of freedom in setting the mag. field distribution is extended largely. Further when the convergence characteristics are to be improved through mag. field distributing action of a deflection yoke, its correction can be made more effective.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a deflection coil for a cathode ray tube.

[Summary of the Invention] In the deflection coil of the present invention, each coil portion that generates a predetermined deflection magnetic field for deflecting a beam is defined as a first region and a second region, respectively, on both sides when viewed from the beam optical axis. In addition, by forming parts in each region where the current directions are opposite to each other, it is possible to obtain a magnetic field distribution that cannot be obtained with normal coil winding. The sections are formed by winding the wire so that one turn is completed in only one region.

[Prior Art] A deflection yoke in a cathode ray tube (CRT) is composed of a pair of vertical deflection coils and a pair of horizontal deflection coils. For example, a horizontal deflection coil is wound around a saddle-shaped bobbin, so that the coil is wound in a saddle shape as shown in Figure 4, and the magnetic field generated by such a saddle-shaped coil is It is determined by the current distribution flowing in the total cross section of the beam, and the Z axis coincides with the beam optical axis. Also,
When shown in plan with the X-axis and Y-axis as reference, the coil winding method is as shown in FIG. 5, and the current flows in the direction shown by arrow i in FIGS. 4 and 5 and in the opposite direction.

The cross section of the coil can be expressed as shown in FIG. 6, with the X and Y axes as references.

Here, the first quadrant in Fig. 6 (right cross section of the coil)
, it is assumed that the current is flowing in the direction from the top of the page through the page, and in the second quadrant (the left cross section of the coil), it is assumed that the current is flowing in the direction from the page layer to the top of the page.

At this time, when looking at the current distribution in the right side section of the coil in FIG. 6, it becomes as shown in FIG. 7, where the vertical axis is the current intensity ■ and the horizontal axis is the angle θ with respect to the X axis. Note that the current distribution on the left cross section is expressed symmetrically with that in Figure 7 (
polarity is reversed).

By the way, it is generally known that convergence characteristics can be improved by manipulating the magnetic field distribution of the deflection yoke, and by changing the shape of the coil or partially adjusting the number of windings, the amount of current in a given part can be reduced. etc. are being carried out. For example, in a coil with a current distribution as shown in Fig. 7, if the number of windings in the portions θ and θゎ is reduced, a current distribution as shown in Fig. 8 can be obtained, and therefore a coil with a predetermined convergence characteristic can be obtained. It is possible to obtain a strong magnetic field.

However, in this method of obtaining a predetermined magnetic field distribution, the limit is a state in which the winding is zero in a predetermined portion. That is, the current distribution state shown in FIG. 9 is obtained when the winding between 08 and 05 is set to zero.

If you want to have more freedom in setting the magnetic field distribution,
For example, by folding the coil in the middle and winding it as shown in Fig. 10, it is possible to obtain a current in the opposite direction, for example, between θ and θゎ. It is also theoretically possible to set the (la-world) distribution state.

[Problems to be Solved by the Invention] However, it is difficult and impractical to wind the coil by folding it back at a certain portion as shown in FIG. 10 above. This is because winding machines that wind coils around coil bobbins are usually designed to always wind in a fixed direction, and a new winding machine must be manufactured in order to perform a turning motion while winding a coil. This results in unnecessary cost and time loss.

For this reason, conventionally, when attempting to actually change the magnetic field distribution state between θ and θゎ, the state shown in Figure 9 above is the limit, and the degree of freedom in setting the magnetic field for convergence correction etc. is small. There was a problem.

[Means for Solving the Problems] The present invention has been made in view of the above problems, and each coil generates a predetermined deflection magnetic field for deflecting the beam on both sides when viewed from the beam optical axis. When the first and second quadrant regions in FIG. 5, FIG. 6, etc. are respectively defined as first and second regions, each of the first and second regions includes The present invention provides a deflection coil in which a coil is wound such that a portion in which one revolution of the coil is completed is formed only within the deflection coil.

[Operation] For example, if a portion where the coil completes one revolution only in one area is formed, as shown as points A to B and points C to D in FIG. 1 over the area of
A current direction iR opposite to the normal current direction 11 when the circuit is wound can be obtained in each region. Moreover, in this case, there is no need to reverse the winding direction of the coil and fold it back.

[Example] Figures 2 (a) to (e) are a plan view, a front view, a bottom view, a side view, and a rear view of a saddle-shaped horizontal deflection coil showing one example of the deflection coil of the present invention. . This horizontal deflection coil has 2
They are attached in pairs to the neck of a cathode ray tube together with a pair of vertical deflection coils, and are configured as a deflection yoke.

2 is a saddle-shaped coil bobbin, 2 to 18 are locking pieces formed symmetrically in front of the bobbin, and 20
28 are locking pieces formed symmetrically at the rear of the bobbin. 30 are respective locking pieces 2 to 18 of the coil bobbin 1.
The coil is shown wound in a saddle shape using 20 to 28 as guides.

In the horizontal deflection coil of this embodiment, the coil 30 is wound so that a portion of the coil that completes one revolution is formed only in one region, as shown in FIG. 3, for example.

That is, the right side in the drawing with the locking piece 2 as the center is the area ■,
Looking at the left side as area (2), in area 1, one revolution is completed in area 1 when reaching point B from point A via locking piece 3. Similarly, in region 2, one revolution is completed only within region 2 when the wire is wound from point 0 to point D via locking piece 11. After point D, all the windings are completed from area 2 to area 1, completing one revolution.

When wound in this manner, a current direction IR opposite to the main deflection current direction 2 is generated in each region. Therefore, a current intensity distribution as shown in FIG. 11 can be obtained, for example, which means that the degree of freedom in setting the magnetic field distribution is expanded. Moreover, there is no need to reverse the winding direction and fold back, and the coil winding can be completed by always winding in a fixed direction. Therefore, the horizontal deflection coil of this example can be easily manufactured using a conventional winding machine. can do.

In addition, in Fig. 3, the reverse direction current is obtained only on the innermost circumferential side of each region, but the portion where the reverse direction should occur and the number of windings thereof are set based on the magnetic field distribution to be generated. In any case, the design may be such that one round is completed only within that area.

It goes without saying that the present invention can also be implemented as a vertical deflection coil.

[Effects of the Invention] As explained above, in the deflection coil of the present invention, the coil is wound in each of the first and second regions such that a portion where one revolution of the coil is completed only within that region is formed. This has the effect that it is possible to easily manufacture a deflection coil having a portion in which current flows in the opposite direction, which has been difficult to manufacture in the past.

Therefore, it is now possible to easily obtain a magnetic field distribution that was difficult to obtain in the past, and the degree of freedom in setting the magnetic field distribution is greatly expanded. Correction can be made more effective.

A plan view, a front view, a bottom view, a side view, and a rear view of one embodiment of the present invention, Fig. 3 is an explanatory diagram of the coil winding method of this embodiment, and Fig. 4 is an example of a saddle-shaped horizontal deflection coil. FIG. 5 is an explanatory diagram of a normal coil winding system, and FIG. 6 is a schematic diagram of a cross section of the coil.

Figure 7 is an explanatory diagram of the current distribution, Figure 8 is an explanatory diagram when the current distribution is changed by reducing the number of coil windings in a specific part, and Figure 9 is an illustration of the current distribution when the number of coil windings is reduced in a specific part. An explanatory diagram when the distribution is changed. Figure 1O is an explanatory diagram when the coil winding direction is turned back to obtain a reverse current.

FIG. 11 is an explanatory diagram when the current distribution is changed by a reverse current.

[Brief explanation of the drawing]

Figure 1 shows the coil winding method of the deflection coil of the present invention (Figure 2).
a), (b), (c), (d), and (e) are the present invention. (2) is a coil bobbin, 2 to 18 is a locking piece, 20 to 28 is a locking piece, and 30 is a coil. Second 4! Area of li range sugar 1 (e) (e) (Current 91 degrees

Claims (1)

[Scope of Claims] When each coil portion that generates a predetermined deflection magnetic field for deflecting the beam is defined as a first region and a second region, respectively, on both sides when viewed from the beam optical axis, The coil is wound in each of the second regions so that a portion of the coil completes one revolution only within that region, so that each of the first and second regions receives a current. A deflection coil characterized in that the magnetic field distribution is corrected by forming portions whose directions are opposite to each other.