JPH10326578A - Deflection yoke - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a gull wing pattern of a deflection strain with a deflection yoke with simple constitution. SOLUTION: A bent part conductor on a display surface side of a horizontal deflection coil of a deflection yoke is formed so that its shape is mirror symmetry to the horizontal surface and the vertical surface containing the tube axis of a cathode ray tube as viewed from the display surface side, a side part 1a continuing to a saddle-shaped tube axis direction part 2 in the first quadrant is almost parallel to the vertical symmetry surface of the coil, and a passage part 1b continuing to the side part 1a is formed in an angular shape having an apex in the middle between the symmetry surface and the side part.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a deflection yoke used for a color cathode ray tube.

[0002]

2. Description of the Related Art FIG. 8 shows the appearance of a deflection yoke which is used by being attached to a cathode ray tube in a conventional shape. As shown in FIG. 8, a horizontal deflection coil (81) is provided at a position in contact with the innermost surface of the cathode ray tube, and a separator (8) is overlapped therewith.
2), a vertical deflection coil (83) and a core (84) are assembled in this order. The separator (82) is assembled for separating the horizontal deflection coil (81) and the vertical deflection coil (83) and maintaining the shape.

[0003] Such a saddle-type horizontal deflection coil (81)
In the deflection yoke having the horizontal deflection coils (8
The bend portion conductor (81a) on the cathode ray tube display surface side of 1) is formed in a substantially arc shape.

FIGS. 3 and 4 show examples of scanning lines on a cathode ray tube display screen by an electron beam deflected by such a deflection yoke. If the curvature of the display surface (31) of the cathode ray tube is small and the difference between the display surface (31) and the sphere in contact with the display surface around the center of deflection is large, if the deflection magnetic field is made uniform, scanning is performed above and below the display surface (31) of the cathode ray tube. The distortion of the scanning line (32) takes a pincushion shape as shown in FIG.

In order to reduce the upper and lower pincushion distortion, the winding method of the horizontal deflection coil is adjusted so that the magnetic field lines of the magnetic field generated on the cathode ray tube display surface side of the horizontal deflection coil have a pincushion shape.

However, as the horizontal deflection magnetic field becomes pincushion-shaped, as shown in FIG. 4, the scanning line (41) is bent inside the display screen at the A portion near the left and right ends of the scanning line and the B portion at the center. 2nd harmonic distortion and raster distortion in the shape of a bird wing (hereinafter referred to as “gull wing pattern”).

Conventionally, it is difficult to correct such second harmonic distortion using only a coil. For example, an electric circuit for correcting second harmonic distortion is provided, or Japanese Unexamined Patent Application Publication No. 8-25 / 1996.
As disclosed in Japanese Patent Application Publication No. 0041, the correction is made by attaching permanent magnets above and below the coil.

[0008]

However, in the above-described correction method, the number of parts increases to correct the gull wing pattern, the structure becomes complicated, and the weight also increases. In addition, there is a problem that a variation in correction capability occurs due to an error in mounting a magnet, and that when a product is mass-produced, a distortion shape varies depending on a product.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-described problems and to realize a magnetic field generated by a deflection coil in order to realize good performance with a simple configuration without adding components for correcting a gull wing pattern. It is to provide a deflection yoke which can be corrected by the following.

[0010]

To achieve the above object, the present invention provides a horizontal deflection coil of a deflection yoke.
The shape of the bend portion conductor (1) on the display surface side of the cathode ray tube is mirror-symmetrical with respect to a horizontal plane and a vertical surface including the tube axis of the cathode ray tube when viewed from the display surface side, and has a saddle shape in the first quadrant. The side part (1a) connected to the pipe axial direction part (2) is substantially parallel to the vertical symmetry plane of the coil, and the following transition part (1b) is a chevron shape having a vertex in the middle between the symmetry plane and the side part. Thus, the gull wing pattern is corrected by the magnetic field generated by the deflection coil.

[0011]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a front view of a half of a horizontal deflection coil of a deflection yoke according to an embodiment of the present invention, as viewed from the display surface side of a cathode ray tube. FIG. 2 shows a side view of this. As shown in FIGS. 1 and 2, the horizontal deflection coil according to the present embodiment includes a display-surface-side bend conductor (1), a saddle-shaped tube-axis-direction conductor (2), and a neck-side bend conductor (3). ).

The display-surface-side bend portion conductor (1) is substantially parallel to a plane perpendicular to the tube axis of the cathode ray tube, and is viewed from the display surface side in a vertical direction (Y-axis direction) including the tube axis. The side surface (1a) connected to the tube axis direction conductor (2) is symmetric with respect to the horizontal direction (X axis direction) plane including the plane and the tube axis, and the Y axis extending vertically through the tube axis of the cathode ray tube. The crossover portion (1b) which is substantially parallel and which is connected to the side surface portion (1a) has a mountain shape having an apex in the middle between the Y-axis direction symmetry surface and the side surface portion.

Hereinafter, the operation of correcting the gull wing pattern by the horizontal deflection coil of the present invention will be described with reference to FIGS.
This will be described with reference to FIG.

FIG. 5 shows a state in which deflection distortion of a gull wing pattern occurs on the display screen of the cathode ray tube. When a gull wing pattern is generated on the screen, to reduce this distortion, for example, the electron beam (5) that reaches the scanning zone, that is, the highest portion (A1) of the distortion pattern is used.
By applying a downward force (F1) to (2) and an upward force (F2) to the electron beam (53) reaching the scanning end (A2), the gull wing pattern can move in a direction in which it is reduced. Recognize.

Therefore, the present invention has devised a coil shape capable of generating the above-mentioned force. The operation of the horizontal deflection coil of the present invention will be described with reference to FIG. FIG.
Is a view of the horizontal deflection coil viewed from the display surface of the cathode ray tube. In FIG. 6, the electron beam (52) directed to the zone of the scanning line and the electron beam (53) directed to the end of the scanning line shown in FIG. The two electron beams are emitted from the electron gun, pass through a surface formed by the display surface side bend portion conductor (1) of the horizontal deflection coil, and further proceed slightly to the display surface side, where the display surface side bend portion conductor ( 1)
And come near points (54) and (55), respectively.
At this time, the electron beam is most strongly affected by the magnetic field generated by the display surface side bend portion conductor (1).

Here, it is known that the vertical (Y-direction) component Fy of the force acting on the electron beam by the magnetic field is expressed by the following equation.

Fy = −e * (Vz * Bx−Vx * Bz) (1) where e is the charge amount of the electron, Vx and Vz are the X and Z components of the electron velocity, and Bx and Bz are These are the X and Z components of the magnetic field.

In the above equation (1), the second term is the Z of the magnetic field.
Although the Z component of the magnetic field due to the display surface side bend portion conductor (1) is a negative value everywhere in the XY plane shown in FIG. It can be seen that it is difficult to make a large change between 52) and the trajectory (53).

The first term in the above equation (1) is based on the X component (ie, the horizontal component) of the magnetic field. In the present invention, the above-mentioned two electron beams are improved by devising the shape of the display surface side bend portion conductor (1). It has been found that it can be greatly changed depending on the orbit. As shown in FIG. 6, at points (54) and (55) where the electron beam trajectories (52) and (53) are closest to the display surface side bend portion conductor (1), the magnetic field due to the bend portion is X shown in FIG. The component in the −Y plane is also large. Looking at the XY component of this magnetic field, the crossover portion (1b) of the display surface side bend portion conductor (1) is formed into a mountain shape as shown in FIG. The magnetic field generated by the portion on the Y side is in the direction indicated by the arrow (B1), and the magnetic field generated by the portion on the side surface (1a) side from the top of the mountain is in the direction indicated by (B2).

Then, the electron beam (52) heading for the zone portion of the scanning line receives a force from the magnetic field (B1) generated at the point (54) from the apex of the peak on the side of the symmetry plane. Since the magnetic field (B1) has a positive X component, the beam (5
2) A downward force is applied. Also, the electron beam (53) heading toward the end of the scanning line at point (55)
It is affected by the magnetic field (B2) generated by the portion on the side (1a) side from the peak of the mountain. Since the magnetic field (B2) has a negative X component, an upward force acts on the beam (53). That is, this is the same as the required forces (F1) and (F2) as shown in FIG. Therefore, it can be seen that according to the present invention, it works to reduce the gull wing pattern.

On the other hand, in the conventional display-surface-side bend-portion conductor (56) having the shape shown by the thin practice in FIG.
The magnetic fields at 4) and (55) are in the directions shown by arrows (B1 ') and (B2'), and since both magnetic fields have negative X components, both beams (52) and (53) are directed upward. It can be seen that the gull wing pattern is not reduced.

As described above, by forming the crossover portion (1b) of the display-surface-side bend portion conductor into a mountain shape, the Y direction opposite to the beam toward the middle portion and the beam toward the end portion of the gull wing pattern is obtained. The effect of exerting a directional force is produced, whereby the gull wing pattern can be reduced.

The positions of the peaks of the chevron shape of the transition portion (1b) are the positions where the magnetic fields (B1) and (B2) shown in FIG. 6 act effectively on the electron beams (52) and (53). Must be set to In FIG. 6, the transition portion (1b)
Let Lx be the distance from the Y axis to the vertex of the chevron shape of R, and let R be the radius of the circle (57) on the inner surface of the cathode ray tube in a section perpendicular to the tube axis near the display surface side bend conductor (1). . As shown in FIG. 6, the X coordinate of a point (55) slightly closer to the display surface side from the display surface side bend portion conductor (1) of the electron beam (53) toward the end of the scanning line is substantially the radius of the inner surface circle of the cathode ray tube. R, the magnetic fields (B1) and (B
In order for 2) to effectively act on the electron beams (52) and (53), it is desirable that the value of Lx be larger than a value close to R / 2.

FIG. 7 shows an example in which a change in the residual amount of the gull wing pattern when Lx is changed is obtained by simulation. From FIG. 7, it can be seen that the residual amount of the gull wing pattern is reduced when Lx / R is 0.4 or more. Therefore, it is appropriate that the value of Lx be 0.4 times or more of R.

As described above, according to the present invention, the gull wing pattern of deflection distortion can be reduced by the magnetic field generated by the horizontal deflection coil itself, and a deflection yoke with good performance can be obtained without adding extra parts. it can.

[0027]

As described above, according to the present invention, the gull wing pattern of the deflection distortion is reduced by the magnetic field generated by the deflection coil itself without adding an extra part such as a permanent magnet, and a simple configuration. A deflection yoke with good performance can be realized.

[Brief description of the drawings]

FIG. 1 is a front view showing a half of a horizontal deflection coil of a deflection yoke according to an embodiment of the present invention.

FIG. 2 is a side view showing a half of a horizontal deflection coil of the deflection yoke according to the embodiment of the present invention.

FIG. 3 is a conceptual diagram showing an example of deflection distortion caused by a uniform magnetic field.

FIG. 4 is a conceptual diagram showing higher-order deflection distortion (gull wing pattern) generated by a conventional deflection yoke.

FIG. 5 is a schematic diagram showing the state of a beam in a cathode ray tube and a gull wing pattern on a display surface.

FIG. 6 is a schematic diagram showing the principle of gull wing pattern correction according to the present invention.

FIG. 7 is a graph showing a relationship between a position of a vertex of a chevron shape and a gull wing pattern correction amount.

FIG. 8 is a perspective view showing a configuration of a conventional deflection yoke.

[Explanation of symbols]

Reference numeral 1 denotes a display surface side bend conductor of the horizontal deflection coil of the present invention;
··········································································································································· 53
... Electron beam heading toward the end of the scanning line, 56... Bend conductor on the display surface side of a conventional horizontal deflection coil, 57... Cross section circle of the inner surface of a cathode ray tube, 81. Deflection coil, 84 ... core.

 ──────────────────────────────────────────────────の Continued on the front page (72) Inventor Katsuyuki Kawakami 292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa Pref. Multimedia Systems Development Headquarters, Hitachi, Ltd. (72) Inventor Soichi Sakurai Yoshida, Totsuka-ku, Yokohama, Kanagawa Prefecture No. 292, Hitachi, Ltd. Multimedia Systems Development Headquarters, Hitachi, Ltd. (72) Inventor, Misao Ikeda 3300, Hayano, Mobara, Chiba Prefecture, Electronic Devices Division, Hitachi, Ltd. 1 Jono Kitano Inside Hitachi Media Electronics Co., Ltd.

Claims (3)

[Claims] A horizontal deflection coil formed in a saddle shape;
In a deflection yoke used by being attached to a cathode ray tube, the shape of the bend portion conductor (1) on the display surface side of the cathode ray tube is such that the shape of the bend conductor (1) with respect to a horizontal plane and a vertical plane including the tube axis of the cathode ray tube when viewed from the display surface side In the first quadrant, the side portion (1a) connected to the saddle-shaped tube axial portion (2) is substantially parallel to the vertical symmetry plane of the coil, and the following crossover portion (1b) is symmetric. A deflection yoke comprising a horizontal deflection coil having a mountain-like shape having a vertex between a surface and a side surface. 2. A distance between an apex of a chevron shape and a vertical symmetry plane of the horizontal deflection coil at a transition portion (1b) of the display surface side bend portion conductor (1) of the horizontal deflection coil according to claim 1. A deflection yoke having a radius larger than 0.4 times a radius of a cross-sectional circle of an inner surface of the cathode ray tube on a plane including the bend portion conductor. 3. A cathode ray tube device equipped with the deflection yoke according to claim 1.