KR100398703B1 - Deflection yoke for Broun tube - Google Patents

Abstract

The present invention relates to a deflection yoke used in a CRT. In the present invention, the ferrite core shape of the region extending from 10 to 50% of the total length of the ferrite core from the screen side end portion 45a to the neck portion 45b in the entire portion of the ferrite core 45 is parallel to the tube axis of the CRT. It is designed to be. By reducing the amount of leakage of the main deflection magnetic field generated in the main body region of the horizontal deflection coil, it is possible to improve the conventional problem that the deterioration of the horizontal deflection sensitivity of the deflection yoke 4 and the ringing characteristics are deteriorated.

Description

Deflection yoke for Broun tube

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to deflection yokes for use in CRTs, and more particularly to deflection yokes for CRTs for reducing the leakage magnetic field of deflection yokes for CRTs in which horizontal and vertical coils are saddle saddle shaped.

A cross-sectional view of a typical CRT is shown in FIG. 1.

As shown in FIG. 1, the configuration of the CRT includes an electron gun 3 emitting three electron beams, a screen 1 in which these electron beams strike a fluorescent surface 12 to reproduce light, and the three electron beams 14. ) And a deflection yoke 4 for deflecting the electron beam to a predetermined place of the screen (or screen) 1.

Looking at the configuration of the prior art for the deflection yoke 4 described above with reference to FIG. The deflection yoke 4 has horizontal deflection coils 41a and 41b for horizontally deflecting the electron beam emitted from the electron gun 3 inside the CRT as shown in FIG. Cone type used to increase magnetic efficiency by reducing the loss of magnetic force generated in the vertical deflection coils 42a and 42b and the horizontal deflection coils 41a and 41b and the vertical deflection coils 42a and 42b to deflect in the direction. The ferrite core 44, and the coils 41a, 41b, 42a, 42b and the ferrite core 44 are fixed to a predetermined position, and the horizontal deflection coils 41a, 41b and the vertical deflection coils 42a, 42b are fixed. It is composed of a holder 43 for insulation between the).

The leakage magnetic field pattern of the cross section and the deflection yoke 4 with respect to FIG. 2 configured as described above will be described with reference to FIG. 3. As shown in FIG. 3, the upper and lower sides of the holder 43 shown in FIG. 2 to offset the leakage magnetic field generated in the screen portion 10 and the neck part 20 of the deflection yoke 4. After attaching a pair of cancel coils 5 and 5 'to the screen portion, the pair of cancel coils 5 and 5' is composed of a horizontal deflection coil 41a and 41b, a resistor 6 and a condenser 7. The leakage magnetic field generated in the deflection yoke 4 is canceled by coupling to the horizontal deflection circuit shown in (a) of FIG. The horizontal deflection current waveform shown in FIG. 4B is shown on the right.

Referring to the operation of the prior art configured as described above is as follows.

The above-described conventional deflection yoke 4 flows a current having a frequency of 15.75 KHz or higher to the horizontal deflection coils 41a and 41b in a horizontal direction by using the magnetic field generated thereby. In addition, the vertical deflection coils 42a and 42b are supplied with a current having a frequency of 60 Hz, and the electron beam is deflected in the vertical direction by using a magnetic field generated accordingly. Then, by using the non-uniform magnetic field by the horizontal deflection coils 41a and 41b and the vertical deflection coils 42a and 42b, the convergence of the three electron beams on the screen even without using additional circuits and additional devices. A self-converging deflection yoke (4) is being developed which makes it possible to achieve. That is, the winding distribution of the horizontal deflection coils 41a and 41b and the vertical deflection coils 42a and 42b is adjusted to produce a barrel or pin-cushion type magnetic field for each part (opening part, middle part, and neck part). This allows the three electron beams to experience different deflection forces, depending on their location, so that they can be collected at the same point at different distances from the starting point of the electron beam to the screen (or screen) 1, which is the destination. When a current is supplied to (41a, 41b, 42a, 42b) to create a magnetic field, it is difficult to deflect the electron beam to the front of the screen only by the magnetic field by the coil, and the ferrite core 44 of high permeability is used on the return path of the magnetic field. By minimizing the loss, the magnetic field is increased to increase the magnetic force.

In addition, as shown in FIG. 3, in the screen portion 10 and the neck portion 20 of the deflection yoke 4, unnecessary leakage magnetic fields other than the main deflection magnetic field for deflecting the electron beam in the horizontal and vertical directions of the screen are generated. Adversely affect the human body. In order to improve this phenomenon, as shown in FIG. 2, a pair of cancel coils 5 and 5 ′ are attached to upper and lower screen portions of the holder 43. In detail, the principle of canceling the leakage magnetic field is described. First, a pair of cancel coils 5 and 5 'are connected in series, and as shown in FIG. 3, a pair of cancel coils are connected to a horizontal deflection circuit. Is a pair of canceling coils (5) connected so that the main magnetic field generated by the horizontal deflection current flowing through the leakage magnetic field generated in the opening of the horizontal deflection coil and the pair of canceling coils 5 and 5 'is offset in the opposite direction. 5 '), the leakage magnetic field generated in the screen portion 10 and the neck portion 20 of the deflection yoke can be offset as shown in FIG.

As described above, the conventional technique of attaching a pair of cancel coils 5 and 5 'to the upper and lower screen portions of the holder 43 to cancel the leakage magnetic field of the deflection yoke has three problems as follows.

First, in order to offset the leakage magnetic field generated by the deflection yoke 4, a pair of cancellation coils 5 and 5 'are attached to upper and lower screen portions of the holder 43, and then a pair of cancellation coils in series with the horizontal deflection circuit. In the method of connecting (5, 5 '), the inductance value of the pair of cancel coils (5, 5') is added in series to the inductances of the horizontal deflection coils (41a, 41b) in order to maintain the same horizontal deflection inductance. The inductance of the deflection coils 41a and 41b should be reduced. This causes a problem of lowering the horizontal deflection sensitivity. This decrease in the horizontal deflection sensitivity results in a decrease in the screen size. In order to match the same screen size, an increase in the horizontal deflection current is inevitable, and an increase in the horizontal deflection current further deteriorates the heat generation characteristics generated in the deflection yoke (4). There is a problem that can reduce the quality of (4).

Second, attaching a pair of canceling coils 5 and 5 'to the horizontal deflection circuit discharges the current charged by the stray capacitance between the coil and the coil wound around the pair of canceling coils at the return time of the horizontal deflection current. Ringing is generated on the left side of the screen as shown in FIG. 5, and a pair of resistors 6 and a capacitor 7 are shown in parallel with a pair of canceling coils 5 and 5 'in a horizontal deflection circuit to cancel them. The linking phenomenon is canceled by connecting as shown in Fig. 4A. In this way, there is a problem that the material cost of the deflection yoke 4 is increased, which seriously affects the profitability of the enterprise.

Third, the method of attaching the pair of cancellation coils 5 and 5 'to the horizontal deflection circuit as shown in Fig. 2 covers the lead wires when connecting the lead wires of the pair of cancellation coils 5 and 5' to the horizontal deflection circuit. In order to prevent spark phenomenon with the vertical deflection coil due to peeling, the lead wire is protected by using an insulation tube.A separate terminal is inserted into the terminal plate to connect to the horizontal deflection circuit. ) Is connecting. Such a method causes a material cost increase of the deflection yoke 4 and an increase in the number of working processes during assembly, which seriously affects the deterioration of profitability of the company.

Therefore, in order to solve the above problems, in the present invention, the shape of the near end of the screen side of the ferrite core is mounted in parallel with the tube axis of the CRT so that the main deflection magnetic field leaks into the opening of the horizontal deflection coil to the screen side of the CRT. The purpose is to improve the leakage magnetic field characteristics generated in the deflection yoke by reducing the amount of magnetic field.

The deflection yoke for the CRT of the present invention for achieving the above object is the shape of the ferrite core surrounding the horizontal and vertical deflection coils in the deflection yoke, the inner surface shape of the ferrite core in the region from the screen end to the center. By making the shape parallel to the tube axis of the CRT, it not only reduces the leakage of the main deflection magnetic field of the horizontal deflection coil, but also improves the horizontal deflection sensitivity and improves the ringing characteristics on the screen. In addition, the deflection yoke for the CRT of the present invention has a loop-shaped cancel attached to each of the upper and lower screen portions of the holder in a method of canceling unnecessary leakage magnetic fields generated in the horizontal deflection coil 41 of the deflection yoke 4 as in the prior art. In the present invention, unlike the method of canceling the unnecessary leakage magnetic field by applying a horizontal deflection current in series to the coil so that the magnetic field is in the opposite direction to the leakage magnetic field of the main deflection magnetic field of the horizontal deflection coil in the present invention This structure is unnecessary.

1 is a cross-sectional view of a typical CRT,

2 is a schematic diagram of a conventional deflection yoke;

3 is a leakage magnetic field pattern diagram of a conventional deflection yoke;

4 is a diagram illustrating a horizontal deflection circuit and a horizontal deflection current of a conventional deflection yoke;

5 is a ringing pattern diagram of a conventional deflection yoke,

6 is an assembly view of the deflection yoke of the present invention;

7 is a side view of the ferrite core of the present invention,

8 is a leakage magnetic field pattern diagram of a deflection yoke of the present invention.

<Explanation of symbols for main parts of drawing>

45: ferrite core 45a: end

45b: neck portion

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to deflection yokes for use in CRTs, and more particularly to deflection yokes for CRTs having means for canceling out unwanted leakage magnetic fields generated by deflection yokes in the vicinity of CRTs.

As described above with reference to FIG. 1, the CRT includes an electron gun 3 that emits three electron beams, a screen 1 where these beams collide, and reproduces light, and a shadow mask 2 that distinguishes the three electron beams. ) And a deflection yoke 4 or the like which deflects the electron beam to a predetermined place of the screen 1.

Here, the deflection yoke 4 according to the present invention, as shown in FIG. 6, is provided in the opening 15 to horizontally deflect the electron beam emitted from the electron gun 3 inside the CRT. The deflection coil 41, the vertical deflection coil 42 for deflecting the emitted electron beam in the vertical direction, and the magnetic force generated in the horizontal and vertical deflection coils 41 and 42 are reduced to increase the magnetic efficiency. To fix the conical ferrite core 45 and the coils 41 and 42 and the core 45 to a predetermined position and to insulate between the horizontal deflection coil 41 and the vertical deflection coil 42. It is composed of a holder 43 for.

In addition, it has recently been desired to suppress unnecessary leakage magnetic fields generated around a CRT tube to a predetermined value or less. Among them, in the extreme low frequency (ELF) range of 5Hz to 2KHz, and the ultra low frequency (VLF) range of 2KHz to 400KHz, this unnecessary magnetic field is a leakage magnetic field. It is included as. In particular, since the frequency range in the VLF band may adversely affect the human body, special measures are required to reduce the leakage magnetic field of the VLF band. Various methods of suppressing such a leakage magnetic field have been proposed, and among them, in order to cancel the leakage magnetic field, attaching a cancellation coil to the deflection yoke as in FIG. 2 is used in the conventional method.

According to the present invention, the ferrite core 45 provided in the deflection yoke 4 will be described with reference to the leakage magnetic field pattern diagram of the deflection yoke of FIG.

As shown in FIG. 7, the ferrite core 45 of the present invention is in the range of 10% to 50% of the total length of the ferrite core from the screen side end portion 45a to the neck portion 45b in the entire portion of the core. The shape of the ferrite core in the area leading up is designed to be parallel to the tube axis of the CRT, rather than in a manner similar to that of the outer surface of the vertical deflection coil 42 as in the prior art. As described above, the amount of leakage of the main deflection magnetic field generated in the main body region of the horizontal deflection coil as shown in FIG. 8 is reduced, thereby degrading the horizontal deflection sensitivity of the deflection yoke 4 and deteriorating ringing characteristics. It is possible to improve the conventional problem.

Referring to the operation of the present invention configured as described above are as follows.

First, in the pattern of the leakage magnetic field generated in the deflection yoke 4, as shown in Fig. 8, the leakage magnetic field of the unnecessary main deflection magnetic field generated at the opening side and the unnecessary main deflection magnetic field generated at the neck portion are generated, respectively. . Among them, the leakage magnetic field generated from the neck part is normally applied to the shield case mounted inside the monitor to receive the magnetic field generated from the deflection yoke, thereby generating a reverse magnetic field to offset the magnetic field leaked from the deflection yoke. The leakage magnetic field generated in the direction should only be reduced in the deflection yoke, or the leakage magnetic field should be offset by installing a separate leakage magnetic offset component. However, in the present invention, by changing the shape of the existing ferrite core surrounding the outer surface of the horizontal and vertical deflection coil in order to increase the magnetic efficiency without attaching a separate leakage magnetic offset device is generated on the screen side as shown in FIG. A method of reducing the amount of leakage magnetic field is proposed.

Accordingly, the horizontal deflection magnetic field generated by the horizontal deflection coil 41 is largely composed of two types of magnetic field couplings.

First, the magnetic field of the inner surface region that is very close to the horizontal deflection coils 41a and 41b has a magnetic field shape that is interlocked with the inner surface shape of the horizontal deflection coils 41a and 41b, and the inner surface of the horizontal deflection coil except the region that is very close to the horizontal deflection coils 41a and 41b. And the magnetic field of the outer surface is vertically incident on the inner surface of the ferrite core 45 having the high permeability surrounding the horizontal deflection coils 41a and 41b and moves through the body of the ferrite core 45 to ferrite as shown in FIG. 8. The magnetic field emerges in a direction perpendicular to the inner surface of the core. In the conventional ferrite core 44, the screen portion 44a and the neck portion 44b are designed to have a shape similar to the outer surface of the horizontal and vertical deflection coils as shown in FIG. 6, the angle formed with the tube axis of the CRT is maximum, and the inner surface shape of the ferrite core 44 also has the maximum angle. Therefore, the magnetic field coming out through the inner surface of the opening-side ferrite core 44 has a form of a magnetic field directed toward the screen portion 44a as shown in FIG. 8 (a), and the magnetic field leaks to the front surface of the CRT and causes damage to the human body. It will act as a harmful leakage magnetic field.

In contrast, in the present invention, the angle between the inner surface of the ferrite core 45 and the tube axis of the CRT is the maximum near the screen end of the ferrite core 45, that is, from the screen end 45a to the neck 45b. The inner surface shape of the ferrite core 45 in a region ranging from 10% to 50% of the total length of the ferrite core 45 in the direction of) is designed to be parallel to the tube axis of the CRT as shown in FIG. As shown in b), the direction of the horizontal deflection magnetic field coming out through the inner surface of the ferrite core 45 is orthogonal to the tube axis, so that the amount of leakage magnetic field coming out of the front part of the CRT, that is, the screen side, can satisfy the international standard TCO 99. It can be reduced to a level.

At this time, the setting of the area where the inner surface shape of the ferrite core 45 is parallel to the tube axis of the CRT has a smaller cross-sectional area formed by the ferrite core 45 in the entire area of the deflection yoke 4 than the screen side. Because of the high deflection magnetic field density generated at, from the neck portion 45b of the ferrite core 45 to the intermediate region of the ferrite core 45 sensitively to the deflection sensitivity, the outer shape of the vertical deflection coil 42 and By forming the same, the deterioration of the deflection sensitivity is avoided, and the angle formed with the tube axis of the CRT is a relatively large area compared to the neck portion 45b, that is, the angle at which the inner shape of the ferrite core 45 forms with the tube axis starts to increase. The area of the ferrite core 45 that becomes the maximum from the vicinity, that is, the area that reaches 10% to 50% of the entire length of the ferrite core 45 in the direction from the screen side end portion 45a to the neck portion 45b. By maximizing the amount of reduction of the leakage magnetic field which leaks to the inner shape of the ferrite core 45 toward the screen of the picture tube and the tube axis of the cathode-ray tube forming hameuroseo parallel to the deflection yoke (4) is to obtain the characteristics.

The deflection yoke for the CRT to which the ferrite core of the present invention is applied as described above has the following effects.

First, if the ferrite core of the present invention is applied to the problems such as deterioration of the horizontal deflection sensitivity, deterioration of the ringing characteristics, and the increase of the unit cost, which occur when a pair of cancellation coils are applied as in the prior art, a separate auxiliary component is not required. By reducing the amount of leakage magnetic field while increasing the horizontal and vertical deflection efficiency of the system, no additional cost is required to produce the deflection yoke, and the reduction of the horizontal deflection sensitivity and other side effects of the auxiliary circuit application can be improved. In particular, in the case of the wide-angle deflection, that is, the deflection yoke for deflection of 90 to 110 degrees, the angle between the tube axis and the curvature of the screen-side inner surface of the ferrite core is 20% to 30% larger than that of the conventional one, and thus the leakage magnetic field of the opening Since there is a problem that the leakage amount of is increased, the application of the ferrite core of the present invention is absolutely necessary.

Secondly, since the inner diameter near the screen side of the ferrite core becomes larger than the conventional one, the center of the deflection magnetic field of the vertical deflection coil can be moved to the neck portion side. In other words, when the deflection center of the vertical deflection coil is moved toward the neck side, the vertical deflection angle is reduced, thereby reducing the upper and lower raster distortion on the screen, thereby realizing high quality deflection yoke.

Claims (3)

With a deflection yoke for a CRT comprising a horizontal deflection coil, a vertical deflection coil, a holder for holding the coils and ferrite cores in a fixed position and insulating the coils between the coils, The ferrite core surrounding the horizontal and vertical deflection coil is a deflection yoke for the CRT, characterized in that a predetermined region of its inner surface is directed to the neck portion in a shape parallel to the tube axis of the CRT from the end of the screen side. The method of claim 1, A certain region of the ferrite core parallel to the tube axis of the CRT is a deflection yoke for the CRT, characterized in that the configuration of 10% to 50% of the total length of the ferrite core. The method of claim 1, The ferrite core is a deflection yoke for a CRT tube, characterized in that the inner surface region of 10% to 50% of the total length is configured in the same manner as the outer surface shape of the vertical deflection coil from the neck side to the end side.