JPH07192654A - Deflecting yoke and cathode-ray tube display device - Google Patents

Abstract

PURPOSE:To reduce an unnecessary radiation magnetic field without additionally providing a particular means. CONSTITUTION:Relating to a side conductor length Ls of a horizontal deflection coil 2, a ferrite core 4 is set to a length exceeding 60% and less than 70%, and a distance between a front end of the ferrite core 4 and a fluorescent screen side fringe 9 of the horizontal deflection coil 2 is also set to from 15% to less than 20%. Or further, the fluorescent screen side fringe 9 of the horizontal deflection coil 2 is divided into two or more parts in a direction of a tube axis 11.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a deflection yoke attached to a cathode ray tube and a cathode ray tube display device using the same.

[0002]

2. Description of the Related Art In a conventional cathode ray tube, in order to reduce an unnecessary radiation magnetic field, a pair of upper and lower loop-shaped cancel coils are provided at the upper and lower positions on the fluorescent surface side of a deflection yoke for horizontal deflection by direct or inductive connection. A correction current synchronized with the current was applied to generate a canceling magnetic field having a polarity opposite to that of the unwanted radiation magnetic field generated from the deflection yoke.
Hereinafter referred to as the first conventional technology). Most of the countermeasures against the unwanted radiant magnetic field that have been put to practical use so far use such a method.

On the other hand, there has been proposed a technique for reducing the unwanted radiation magnetic field itself by improving the structure of the deflection yoke body without providing any additional one.

One of the methods (second prior art) is disclosed in Japanese Patent Laid-Open No. 165427/1993.
The length of the ferrite core of the deflection yoke is the length in the tube axis direction of the conductor part between the crossover part on the fluorescent surface side and the crossover part on the electron gun side of the horizontal deflection coil (hereinafter, this part is the side conductor part, this length Is referred to as the side conductor length, and the crossover portion is formed to 40% to 60% of the fringe). Further, it is described that the distance from the front end of the ferrite core to the fringe portion on the fluorescent surface side of the horizontal deflection coil is set to 20% to 40% of the side conductor length of the horizontal deflection coil.

Another method (third prior art) is disclosed in Japanese Laid-Open Patent Publication No.
As described in JP-A-112038, the fringe portion on the fluorescent surface side of the horizontal deflection coil is inclined so as to be tilted toward the fluorescent surface side of the cathode ray tube (forward).

Next, when attention is paid to the similar structure of the horizontal deflection coil, as described in JP-B-57-34673, the fringes on the fluorescent surface side of the horizontal deflection coil are divided into a plurality in the axial direction, From the beginning to the end of winding, the position is sequentially shifted forward (or rearward) in the tube axis direction in correspondence with each winding groove of the side conductor portion (this is hereinafter referred to as the fourth conventional technique). .

[0007]

In the first prior art described above, it was necessary to additionally provide a loop-shaped cancel coil, which increased the number of parts and the number of wiring steps, leading to an increase in cost. Furthermore, when the loop cancel coil is connected to the horizontal deflection circuit, the deflection sensitivity is deteriorated by several percent.

In the second prior art, the ferrite core length becomes extremely short as a result, so that the basic characteristics of the deflection yoke such as deflection sensitivity, neck shadow margin (BSN), temperature rise, and convergence characteristic are unnecessary. It was difficult to balance with the reduction of the radiant magnetic field.

In the third prior art described above, since the fringe on the fluorescent surface side is inclined forward, the gap with the cathode ray tube funnel curve is reduced, and the wedge-shaped support for fixing and supporting the deflection yoke is used. It was difficult. Moreover, the amount of correction of the unwanted radiation magnetic field is insufficient only with the forward tilt structure, and further, when an attempt is made to realize a similar structure by the slit bobbin winding method, since there is a tilted part, the structure of the slit bobbin molding die is There was a problem that it became complicated.

In the fourth prior art, since the fringe position is sequentially shifted for each groove of the side conductor portion, the fringe becomes long in the tube axis direction, and there is a structural restriction and a deflection sensitivity characteristic restriction. It will be. Further, the distance between the front end of the ferrite core and the fringe on the fluorescent surface side was not taken into consideration, and the unwanted radiation magnetic field could not be sufficiently reduced.

On the other hand, on the electron gun side of the deflection yoke, a lead wire for wiring from the pair of upper and lower saddle-shaped horizontal deflection coils to the terminal board and a lead wire for wiring from the terminal board to the deflection circuit connection terminal on the board were considered. In this case, a current loop corresponding to one turn to one half turn is configured,
This has been a cause of generating an unnecessary radiation magnetic field in the tube axis direction.

An object of the present invention is to solve the above problem and to reduce the unnecessary radiation magnetic field generated from the deflection yoke by only the structure of the deflection yoke without adding any additional one. To provide.

Another object of the present invention is to provide a cathode ray tube display device having the deflection yoke as described above.

[0014]

In order to achieve the above object, in the deflection yoke of the present invention, the length of the ferrite core in the tube axis direction is 60% of the side conductor length of the horizontal deflection coil.
Over 70% and less than 70%, and the distance in the tube axis direction between the front end of the ferrite core and the rear end of the fringe of the horizontal deflection coil on the fluorescent surface side is set to be 15 times the side conductor length of the horizontal deflection coil.
% To less than 20%.

In addition to the above means, the fringe on the fluorescent surface side of the horizontal deflection coil is divided into two or more in the tube axis direction.

Further, the divided fringes are wound so that the outer diameter dimension in the Y-axis direction perpendicular to the tube axis becomes larger as the fringes located closer to the fluorescent surface side.

Another means for achieving the above-mentioned object is to connect a lead wire connecting each coil to the terminal plate in each of the upper and lower coils of the horizontal deflection coil with a lead wire on the winding start side. The lead wire on the winding end side is placed close to the terminal board and connected to each terminal.On the other hand, the lead wire is also deflected from the terminal board by placing the lead wire on the high potential side and the lead wire on the low potential side in close proximity. Wiring up to the circuit terminal, and between the high-potential side terminal and the low-potential side terminal on the terminal board, the lead wires of the upper and lower coils of the horizontal deflection coil and the lead wire should be placed close to each other. is there.

Further, the deflection yoke is attached to the cathode ray tube.

[0019]

In the horizontal deflection coil, the side conductors and the fringes on the fluorescent surface side, which are located on the fluorescent surface side from the front end of the ferrite core, have a great influence on the amount of unwanted radiation magnetic field generated in front of the deflection yoke. When considering the inner space area of the ferrite core of the deflection yoke as the center, the magnetic field generated by the horizontal deflection coil is generated in the vertical direction. Then, this magnetic field deflects the electron beam in the left-right direction. Letting this be the main deflection magnetic field, the unnecessary radiation magnetic field is a part of the main deflection magnetic field that leaks to the outside at a far distance beyond the deflection magnetic field action region of the electron beam.

On the other hand, the horizontal deflection coil mainly on the fringe and on the fluorescent surface side from the front end of the ferrite core generates a magnetic field in the direction opposite to the main deflection magnetic field in the region on the fluorescent surface side in the tube axis direction. That is, it becomes a component that cancels the unwanted radiation magnetic field. Therefore, since this portion of the horizontal deflection coil can be regarded as a conventional loop-shaped cancel coil, it can be considered that the effect of reducing the unwanted radiation magnetic field is exerted by making the shape large.

When the rear end position of the ferrite core and the horizontal deflection coil is fixed at the same position as the conventional deflection yoke,
Form the ferrite core length to more than 60% and less than 70% of the side conductor length, and set the distance from the front end of the ferrite core to the rear edge of the fringe on the fluorescent surface to be 1 of the side conductor length.
By setting it to 5% to less than 20%, it is possible to suppress the change in the basic performance of the deflection yoke within a practical range and to strengthen the canceling magnetic field action.

Further, by dividing the fringes on the fluorescent surface side of the horizontal deflection coil into two or more in the tube axis direction, the size of the fringe coil becomes smaller in the radial direction perpendicular to the tube axis, and this shape change is caused by the conventional loop. This corresponds to reducing the distance between the upper and lower coils of the shape canceling coil, and enhances the effect of canceling the unwanted radiation magnetic field.

Further, the fringes on the fluorescent surface side divided in the tube axis direction are set by setting the number of coil turns forming each fringe such that the outer diameter size becomes larger as the fringe is located on the fluorescent surface side. Since the size in the radial direction perpendicular to the tube axis can be further reduced without changing the substantial distance from the front end of the ferrite core, the effect of canceling the unwanted radiation magnetic field can be strengthened.

The winding start side and winding end side of each lead wire in each of the upper horizontal deflection coil and the lower horizontal deflection coil are brought close to each other, and the lead wire is also connected to the high potential side lead wire and the low potential side lead wire. The lead wires of the upper horizontal deflection coil and the lower horizontal deflection coil and the lead wire are placed close to each other between the high-potential side terminal and the low-potential side terminal, so that the lead wire can be placed at any position. ,
Since the current directions cancel each other out and no current loop is generated, it is possible to reduce the unwanted radiation magnetic field that has been generated from the lead wire and the lead wire to the outside.

[0025]

Embodiments of the present invention will be described below with reference to the drawings. 1 is a side view showing a first embodiment of a deflection yoke and a cathode ray tube display device according to the present invention, in which 1 is a deflection yoke, 2 is a horizontal deflection coil, 3 is a vertical deflection coil, 4 is a ferrite core, and 6 is a ferrite core. Is a cathode ray tube, 7 is a fluorescent surface of the cathode ray tube 6, 8 is an electron gun of the cathode ray tube 6, 9 is a fringe on the fluorescent surface of the horizontal deflection coil 2, 10 is an electron gun side fringe of the horizontal deflection coil 2, and 11 is The tube axis of the cathode ray tube 6, Ls is the side conductor length of the horizontal deflection coil 2, and Lc is the ferrite core 4.
, Lg is the distance from the front end portion of the ferrite core 4 to the rear end surface of the fringe 9 on the fluorescent surface side of the horizontal deflection coil 2.

In the drawing, in the deflection yoke 1, the fluorescent surface 7 side is the front and the electron gun 8 side is the rear in the tube axis 11 direction.

In this embodiment, the Lc / Ls ratio is about 6
It is set to 5%. This ratio is smaller than that of the conventional deflection yoke (70% or more) that has not been taken. And Lg / Ls
The ratio is set within the range of 15% to less than 20%. The shape of this ratio makes the canceling magnetic field component generated by the horizontal deflection coil 9 on the side of the fluorescent surface 7 mainly having fringes stronger than that of the conventional deflection yoke without countermeasures against unnecessary radiation magnetic field, and is unnecessary around the cathode ray tube 6. The radiant magnetic field can be reduced.

Further, since the core length Lc is not extremely shortened as in the conventional deflection yoke for preventing unwanted radiation, the influence on the basic characteristics such as the deflection sensitivity and the neck shadow margin (BSN) is corrected practically. It can fit within the range.

FIG. 2 is a diagram for explaining the principle of the countermeasure against the unwanted radiation magnetic field in the first embodiment. Here, FIG. 2A shows a state (9-1 to 9-2) in which the fringe 9 on the fluorescent surface side of the horizontal deflection coil 2 is extended forward, and FIG. 2B shows the tube axis 11 at that time. The above horizontal deflection magnetic field amount is qualitatively shown by a curve. In the figure, the wavy line 12 shows how a horizontal deflection magnetic field is generated. Among them, the fringe portion 9-
The solid line 13 on the fluorescent surface 7 side and the solid line 14 on the electron gun 8 side indicate the components generated by 1 (9-2) and 10 respectively.

The magnetic fields 13 and 14 produced by the fringes 9-1 (9-2) and 10 are opposite to the main deflection magnetic field 12 at the positions separated from the deflection yoke 1 toward the fluorescent surface 7 side and the electron gun 8 side. Since it is a component of, when considering the unwanted radiation magnetic field,
Acts as a reducing component. That is, when viewed from the distribution on the axis 11, the amount of magnetic field leaking forward and backward is reduced.

Fluorescent surface side fringe 9-1 having a shape shown by a solid line.
2 is changed to the shape 9-2 indicated by the wavy line, the magnetic field distribution on the axis 11 is reduced from the distribution curve 15 indicated by the solid line to the distribution curve 16 indicated by the wavy line as shown in FIG. 2B.

This operation will be described with reference to FIGS. 3, 4 (a) and 4 (c). FIG. 3 shows a loop-shaped cancel coil 17, and it is well known that the cancel coil 17 is attached to the upper and lower positions on the front end side of the deflection yoke to generate a magnetic field 5 in the opposite direction to cancel the unwanted radiation magnetic field. .

Now, as shown in FIG. 4A, when the loop-shaped cancel coil 17 is attached so that its rear end side overlaps with the fringe 9-1 on the fluorescent surface side of the horizontal deflection coil 2,
Considering the current direction, the portion overlapping with the fringe 9-1 cancels out, and the coil current on the fluorescent surface 7 side of the cancel coil 17 remains. This corresponds to the shape change shown in FIG. That is, the effect of reducing unnecessary radiation generated by extending the fringe 9 toward the fluorescent surface 7 side can be considered to be equivalent to the addition of the cancel coil 17.
FIG. 4B shows the magnetic field distribution on the axis 11 when the cancel coil 17 is added. The cancel magnetic field shown by the distribution curve 5 acts on the main horizontal deflection magnetic field shown by the distribution curve 15, and is unnecessary. The radiant magnetic field is reduced.

Increasing the distance Lg from the front end of the core 4 to the fringe 9 on the fluorescent surface side means that the cancel coil 17 is used.
The area formed by the loop is increased, and the effect of reducing the unwanted radiation magnetic field is increased.

FIG. 5 is an explanatory view of a second embodiment of the deflection yoke and the cathode ray tube display device according to the present invention. here,
The tube axis 11 is taken in the horizontal direction and the Y axis of the cathode ray tube 6 is taken in the vertical direction. As shown in FIG. 5 (a), in this embodiment, the fluorescent surface side fringe 9 is divided into three fringes 9-a, 9-b, 9-c in the tube axis direction. FIG. 5B shows a conventional deflection yoke, in which the fringe 9 is not actually divided, and the coil is concentrated and wound in a single groove. Here, for the sake of explanation, it is shown as being divided into three fringes 9-a, 9-b, and 9-c in the vertical direction. 5C and 5D show the state of the magnetic field 5 generated by the virtual cancel coils 17-1 and 17-2.

In the conventional fringe shape having a single structure as shown in FIG. 5B, since the size in the radial direction perpendicular to the tube axis 11 is large, the distance L from the front end of the ferrite core 4 is large.
Even if g is made long, the position of each coil of the fringe 9 becomes large in the radial direction due to the funnel curve of the cathode ray tube 6. This means that the mounting method of the virtual cancel coil described in FIG. 2 has an angle at the rear. Figure 5
The state is shown in (d). The canceling magnetic field effect of the loop-shaped cancel coil 17 is horizontal or in FIG.
As shown in (c), it is obvious that it is larger to give an angle to the front, and in the cancel coil addition method, a means for tilting the loop cancel coil 17 forward has been put into practical use.

That is, it is preferable that the fringe 9 is extended forward and the radius of the fringe 9 is as small as possible in order to reduce the unnecessary radiation magnetic field. In the embodiment shown in FIG. 5 (a), by dividing the fringe 9 in the tube axis direction, a structure in which the size in the radial direction perpendicular to the tube axis 11 is smaller than in the conventional case is realized.

FIG. 6 is an explanatory diagram of a third embodiment of the deflection yoke and the cathode ray tube display device according to the present invention. even here,
The tube axis 11 is taken in the horizontal direction and the Y axis of the cathode ray tube 6 is taken in the vertical direction.

As shown in FIG. 6 (a), also in this embodiment, the fringe 9 on the fluorescent surface side of the horizontal deflection coil 2 in the direction of the tube axis 11 is divided into three fringes 9-a, 9-b, 9-c. However, the maximum outer diameter in the radial direction increases from the fringe 9-a closer to the fluorescent surface 7 side to the fringes 9-b and 9-c.

When the structure of the conventional fringe 9 on the fluorescent surface side as shown in FIG. 6 (b) is extended forward, in order to minimize the maximum outer diameter in the radial direction and increase the extension distance to the front. As shown in FIGS. 6 (c) and 6 (d), the coils 9-a and 9 located at the upper portion in the radial direction of the conventional fringe are shown.
-B is a method of moving horizontally and obliquely downward. As a result, the structure shown in FIG. In this structure, the effect of the canceling magnetic field due to the shape change is large, and the deterioration of the deflection sensitivity can be small. As a result of the trial production, the unnecessary radiation magnetic field is reduced from 35 nT to 15 nT at the measurement position 50 cm away from the front surface of the cathode ray tube, and the deflection power index is suppressed to an increase value of less than 5%.

FIG. 7 shows a deflection yoke and a cathode ray tube display device according to a fourth embodiment of the present invention.

FIG. 7 (a) is a front view of the rear end side of the deflection yoke 1 as seen from the electron gun 8 side along the tube axis 11, and shows the terminal plate 18 and the terminal plate 18 fixed on the terminal plate 18 for horizontal deflection. A terminal 19-H on the high potential side and a terminal 19 on the low potential side to which the lead wires 20-S, 20-E, 21-S, 21-E of the coil 2 and the lead wires 22-H, 22-C are connected. -C is indicated. Further, FIG. 7B is a schematic diagram showing the positional relationship between the horizontal deflection coil 2 and the respective lead lines 20-S, 20-E, 21-S, 21-E.

FIG. 8A is a diagram showing the wiring condition around the terminal plate 18 of the conventional deflection yoke 1. Conventionally, as shown in the drawing, the reciprocal lead wires 22-H and 22-C and the reciprocal lead wires 21-S and 21-E of the lower horizontal deflection coil are separately wired to the left and right. Considering the current direction and current value flowing through each wire, the combination of the lead wires on both the left and right sides and the lead wire of the lower horizontal deflection coil (22-H and 21-
S), (22-C and 21-E) have opposite current directions, but the current ratio is 1: 0.5. Therefore, when the deflection current value is I, the current of 1 turn of I / 2. A loop will be formed. The situation is shown in FIG. Current loop 2
3 generates a bipolar magnetic field 24 in the direction of the tube axis 11, and is observed especially as a large unnecessary radiation magnetic field in the rear part of the cathode ray tube 6.

In the embodiment shown in FIG. 7, as shown in FIG. 7A, the lead wire 22 and the lead wires 20 and 21 are wired close to each other so as not to form a current loop. For the lead wires 21-S and 21-E, an insulating tube or the like is used to ensure insulation.

According to such wiring means, the current components are canceled out at each part, so that an unnecessary unnecessary radiation magnetic field is not generated and the unnecessary radiation magnetic field in the entire deflection yoke 1 is reduced.

[0046]

As described above, according to the present invention,
Since the basic structure of the deflection yoke itself can form a magnetic field component having a polarity opposite to that of the unnecessary radiation magnetic field generated from the deflection yoke without adding any special means such as a loop-shaped cancel coil, deflection sensitivity and neck The unnecessary radiation magnetic field can be reduced without impairing the basic performance such as the shadow margin (BSN).

Further, since the lead wire and the lead wire can be configured so as not to form a current loop at the rear end portion of the deflection yoke, the unnecessary radiation magnetic field can be reduced.

[Brief description of drawings]

FIG. 1 is a side view showing a first embodiment of a deflection yoke and a cathode ray tube display device according to the present invention.

FIG. 2 is a diagram for explaining the principle of countermeasures against an unwanted radiation magnetic field of the deflection yoke in FIG.

FIG. 3 is a perspective view showing a loop-shaped cancel coil.

FIG. 4 is a principle explanatory diagram of a countermeasure against an unwanted radiation magnetic field by the loop-shaped cancel coil shown in FIG. 3 in the first embodiment shown in FIG.

FIG. 5 is a diagram illustrating a second embodiment of the deflection yoke and the cathode ray tube display device according to the present invention.

FIG. 6 is a diagram for explaining a third embodiment of the deflection yoke and the cathode ray tube display device according to the present invention.

FIG. 7 is a diagram illustrating a fourth embodiment of the deflection yoke and the cathode ray tube display device according to the present invention.

FIG. 8 is a diagram showing a deflection yoke of a conventional example and a dipole magnetic field generated thereby.

[Explanation of symbols]

 1 deflection yoke 2 horizontal deflection coil 3 vertical deflection coil 4 ferrite core 5 cancellation magnetic field 6 cathode ray tube 7 cathode ray tube fluorescent surface 8 cathode ray tube electron gun 9 horizontal deflection coil fluorescent surface side fringe 10 horizontal deflection coil electron gun side fringe 11 cathode ray tube tube axis 17 loop-shaped cancel coil 18 terminal plate 19 terminal 20 lead wire of upper horizontal deflection coil 21 lead wire of lower horizontal deflection coil 22 lead wire

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Nobutaka Okuyama Inventor Noritaka Okuyama 292 Yoshida-cho, Totsuka-ku, Yokohama-shi Kanagawa, Ltd. Video Media Research Laboratories (72) Inventor Yoshio Sato 3300 Hayano, Mobara, Chiba Hitachi, Ltd. (72) Inventor Naoki Ito, No. 1 Kitano, Masaki, Mizusawa-shi, Iwate Hitachi Mizusawa Electronics Co., Ltd.

Claims (5)

[Claims] 1. A saddle-shaped horizontal deflection coil and a saddle-shaped vertical deflection coil attached to a cathode ray tube, and a support for the horizontal deflection coil while maintaining insulation between the horizontal deflection coil and the vertical deflection coil. And a deflection yoke including a separator serving as a winding frame and a ferrite core, the length of the ferrite core in the tube axis direction being defined by a conductor between the fluorescent surface side crossover portion and the electron gun side crossover portion of the horizontal deflection coil. Is formed to be more than 60% and less than 70% of the length in the tube axis direction of the tube, and the tube axis direction of the end portion of the ferrite core on the fluorescent surface side and the rear end surface of the crossover portion of the horizontal deflection coil on the fluorescent surface side. Is formed to be 15% to less than 20% of the length in the tube axis direction of the conductor portion between the crossover portion on the fluorescent surface side and the crossover portion on the electron gun side of the horizontal deflection coil. 2. The deflection yoke according to claim 1, wherein the crossover portion on the fluorescent surface side of the horizontal deflection coil is divided into two or more in the tube axis direction. 3. The horizontal deflection coil according to claim 1, wherein the cross section of the horizontal deflection coil on the fluorescent surface side is divided into two or more in the tube axis direction, and the cross section is perpendicular to the tube axis of each of the divided cross sections of the fluorescent surface. A deflection yoke, wherein the outer diameter in the Y-axis direction is wound so that the crossing portion located closer to the fluorescent surface side becomes larger. 4. A horizontal deflection coil and a vertical deflection coil which are attached to a cathode ray tube and which are composed of a pair of upper and lower saddle-shaped coils, a ferrite core, and between the horizontal deflection coil and the vertical deflection coil. The horizontal deflection coil that maintains insulation
A separator serving as a support for the vertical deflection coil and the ferrite core, a terminal plate having a terminal to which the horizontal deflection coil is connected and serving as a relay point with the deflection circuit, and a deflection circuit terminal on the circuit board from the terminal of the terminal plate. In a deflection yoke composed of lead wires wired up to, a lead wire connecting each of the upper horizontal deflection coil and the lower horizontal deflection coil to the terminal plate is provided with a lead wire on a winding start side and a lead wire on a winding end side. And wire them to the terminal board,
On the other hand, the lead wire is also connected from the terminal board to the deflection circuit terminal by bringing the lead wire on the high potential side and the lead wire on the low potential side close to each other. A deflection yoke, wherein the lead wire of the upper horizontal deflection coil and the lower horizontal deflection coil and the lead wire are arranged close to each other between the high potential side terminal and the low potential side terminal. 5. A cathode ray tube display device comprising a cathode ray tube and the deflection yoke according to any one of claims 1 to 4, which is attached to the cathode ray tube for use.