JP3352520B2 - Deflection yoke and cathode ray tube using the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a deflection yoke of a CRT display device used for a television, a computer display and the like.

[0002]

2. Description of the Related Art In a CRT display device, an electron beam is generated by an electron gun provided inside a neck portion of a glass bulb, and this electron beam is supplied to a deflection yoke provided outside a connection portion between the funnel portion and the neck portion. To deflect in the horizontal and vertical directions. The deflected electron beam reaches a predetermined position on a fluorescent screen provided inside the panel portion of the glass bulb. The electron beam that reaches the phosphor screen causes the phosphor to emit light, thereby displaying an image on the screen. The deflection yoke includes a horizontal deflection coil and a vertical deflection coil. These two deflection coils are fixed inside and outside the hollow insulating support frame, respectively. A deflection yoke is fixed outside the neck portion of the glass bulb so that the neck portion of the glass bulb passes through the hollow portion of the insulating support frame.

When a horizontal deflection coil is fixed inside an insulating support frame and a vertical deflection coil is fixed outside an insulating support frame, a relative error in the position of these two deflection coils with respect to the tube axis of a CRT display device ( Rotation error). In addition, when the assembled deflection yoke is mounted outside the neck portion of the glass bulb, a rotation error of the deflection yoke with respect to the tube axis may occur. Further, when the electron gun is sealed inside the neck portion of the glass bulb, a rotation error with respect to the tube axis of the electron gun may occur. That is, generally, in the assembled CRT display device, the electron gun, the horizontal deflection coil, the vertical deflection coil, and the like have a rotation error with respect to the tube axis.

When an image is actually projected on the screen of a CRT display device, in addition to the effect of rotation error during assembly, the effect of geomagnetism in the direction of the tube axis where the CRT display device is installed is caused by The entire projected image rotates on the screen. As a CRT display device in which such image rotation (raster rotation) has been corrected, for example, the one disclosed in Japanese Utility Model Laid-Open No. 60-20552 is known (it is well known and not shown). That is, in the conventional CRT display device,
A support frame protruding in an arm shape is provided at the end of the deflection yoke on the screen side, and the correction coil wound around the support frame is fixed. Then, a DC current is applied to the correction coil,
A magnetic field is generated in the tube axis direction of the CRT display device. The direction and intensity of the magnetic field generated by the correction coil are adjusted by controlling the DC current supplied to the correction coil, thereby canceling assembly errors and the effects of geomagnetism, and correcting the rotation of the image.

[0005]

However, in the conventional CRT display device in which the raster rotation of the image is corrected, an arm-shaped projecting support frame is provided at the end of the deflection yoke having a large outer diameter on the screen side. Since the correction coil is fixed to the support frame, the outer shape of the entire deflection yoke including the correction coil becomes large. In particular, in recent CRT displays, there is a tendency to increase the deflection angle in order to reduce the depth. Therefore, the inclination of the funnel portion of the glass bulb becomes steep, and accordingly, the outer diameter of the deflection yoke on the screen side increases. Therefore, when a correction coil having the same configuration as the conventional one is provided in a CRT display device having a large deflection angle, there has been a problem that the outer shape of the deflection yoke must be further increased. On the other hand, in recent CRT display devices, it is required to reduce the size of the housing, so that the space around the CRT incorporated in the housing (empty space) is reduced. Therefore, the enlargement of the overall shape of the deflection yoke is not preferable in the design of the CRT display device. Further, in the method in which the correction coil is provided at the screen-side end of the deflection yoke, as the deflection angle increases, the distance between the deflection coil and the electron beam increases, and the correction efficiency decreases.
For this reason, there has been a problem that the number of turns of the correction coil must be increased or the DC current supplied to the correction coil must be increased.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and has a high correction efficiency of raster rotation of an image, a small outer shape, and a large deflection angle.
It is an object of the present invention to provide a deflection yoke suitable for an RT display device.

[0007]

In order to achieve the above object, a deflection yoke according to the present invention comprises a first end located on a screen side of a cathode ray tube and a first end located on a neck portion side of the cathode ray tube. A hollow insulating support frame having a second end having an outer diameter smaller than the end of the hollow support frame, a horizontal deflection coil provided inside the insulating support frame, and a vertical deflection coil provided outside the insulating support frame. comprising a coil, a ferrite core provided outside the vertical deflection coil, the tube axis direction of the cathode ray tube provided inside than the ferrite core and the compensation coil for generating a magnetic field, the correction coil
Is a spiral over almost the entire inside of the ferrite core.
It is wound uniformly . In the above configuration, the correction coil is preferably provided between the vertical deflection coil and the ferrite core . Et al is, it is preferable to use a deflection yoke having the above structures in cathode ray tubes.

[0008]

In each of the above constructions, the correction coil is provided inside the ferrite core having a smaller outer diameter than the screen side end of the cathode ray tube (CRT) of the deflection yoke, and therefore has no correction coil. The outer shape is almost the same as compared with the deflection yoke. In addition, when compared with a conventional correction coil having a correction coil at an end on the screen side, a special shape for holding the correction coil, for example, an arm-shaped projecting support frame or the like is unnecessary, and its outer shape is considerably reduced. . Further, since the correction coil is located at a position very close to the tube axis of the cathode ray tube, the distance between the correction coil and the electron beam is not so large, and the effect of correcting the raster rotation of an image is high. Therefore, the current applied to the correction coil is reduced, and the number of turns of the correction coil is also reduced. Further, by providing the correction coil between the vertical deflection coil and the ferrite core, Wei Soo Rukoto is possible to outline those that do not have a correction coil substantially same size as the deflection yoke. In addition, by spirally winding the correction coil inside the ferrite core, it is possible to use the conventional ferrite core without any special processing.

[0009]

FIG. 5 shows the general structure of a general CRT display device. In FIG. 5, the glass bulb 1
Reference numeral 1 denotes a neck portion, a funnel portion 13, and a face panel portion. Inside the neck part 12,
Three electron beams 18 arranged inline in the horizontal direction
An electron gun 15 for generating (indicated by one in the figure) is provided. A fluorescent screen 16 in which red, blue, and green phosphors are separately arranged is provided on the inner surface of the face panel section 14. In the vicinity of the fluorescent screen 16, a shadow mask 17 having a number of beam passage openings is arranged. The deflection yoke 1 is fixed outside a portion connected from the funnel portion 13 to the neck portion 12.

(First Embodiment) Next, the configuration of a preferred first embodiment of the deflection yoke of the present invention is shown in FIG. In FIG. 1, the insulating support frame 2 is a substantially trumpet-shaped hollow body in which the outer diameter of the screen side end 2a is larger than the outer diameter of the neck side end 2b, and is mainly formed of resin or the like. A horizontal deflection coil 3 is fixed inside the insulating support frame 2, and a vertical deflection coil 4 is fixed outside. A ferrite core 5 is mounted outside the center of the vertical deflection coil 4. A correction coil 6 for correcting raster rotation of an image is spirally and uniformly wound substantially over the entire inner surface of the ferrite core 5. For example, in the case of a 17-inch CRT display device, the wire diameter of the correction coil 6 is 0.2 to 0.3 mm,
The number of turns is 150 turns. The DC current applied to the correction coil 6 is a voltage of 3 to 5 V and a current of 70 to 120 mA.
Is appropriate. If a magnetic field of the same strength is to be generated by the conventional configuration, the diameter and the number of turns of the correction coil are 170 turns, and the applied DC current is about 15
Since 0 mA is required, it is understood that excellent effects are exhibited by the present invention.

The deflection yoke 1 having the above structure is mounted on a CRT display device shown in FIG.
When an image is projected on the image 6 and a raster rotation of the image occurs, when a DC current is applied to the correction coil 6,
A magnetic field is generated in the tube axis direction of the CRT display device.
By adjusting the magnitude and direction of the DC current applied to the correction coil 6, the intensity and direction of the generated magnetic field can be adjusted. Therefore, the raster rotation of the generated image varies depending on the individual CRT display device due to the rotation error of each component at the time of assembling the individual CRT display device and the influence of the geomagnetism on the place where the CRT display device is installed. The rotation is almost completely corrected.

In the first embodiment shown in FIG. 1, the correction coil 6 is spirally wound uniformly over almost the entire surface inside the ferrite core 5. Depending on the number of turns, it may be wound only on a part of the inside of the ferrite core 5 or may be partially wound multiple times. When these correction coils 6 are not wound uniformly, the inner diameter of the correction coil 6 becomes larger when the correction coil 6 is wound around the screen side end 2a side of the deflection yoke 1 so that the tube axis generated by the correction coil 6 becomes larger. The direction correction magnetic field becomes more uniform.

(Second Embodiment) A deflection yoke according to a second embodiment of the present invention is shown in FIG. The members having the same reference numerals as those in FIG. 1 are substantially the same, and the description thereof will be omitted. In FIG. 2, the correction coil 6 is divided into a first correction coil 6a and a second correction coil 6b. The first correction coil 6a is wound around the front end of the ferrite core 5, that is, near the screen-side end 2a of the insulating support frame 2. The second correction coil 6b is wound around the rear end of the ferrite core 5, that is, near the neck-side end 2b of the insulating support frame 2.

When the correction coil 6 is divided into two parts as described above, one of the correction coils, for example, the first correction coil 6a provided on the front end side of the ferrite core 5 is used to correct the DC rotation of the image. It is possible to cause a current to flow, and to flow a reverse direct current to the other correction coil, for example, a second correction coil 6b provided on the rear end side of the ferrite core 5. That is, the magnetic field generated by the second correction coil 6b corrects the disturbance of three beam concentrations on the screen, which is additionally generated by the tube axis magnetic field generated by the first correction coil 6a, so-called convergence disturbance. I do.

On the other hand, when simply correcting the raster rotation of the image, the first correction coil 6a or the second correction coil 6b
Only one of them may be provided. Alternatively, the first correction coil 6a and the second correction coil 6b may be connected in series, and the raster rotation of the image may be corrected by a magnetic field generated by both the coils 6a and 6b. When the number of correction coils is one, the first
Similarly to the first embodiment, the first inner side of the front end of the ferrite core 5 is formed because the substantial inner diameter of the correction coil can be increased.
The correction magnetic field becomes more uniform when the correction coil 6a is provided.

In FIG. 2, a recess is provided inside the ferrite core 5 to accommodate the correction coils 6a and 6b, but the degree of the recess depends on the thickness and the number of windings of the correction coils 6a and 6b. It should be designed accordingly, and in some cases the coil can be accommodated without providing a recess.

In the first and second embodiments, the correction coils 6, 6a and 6b are provided inside the ferrite core 5 and outside the vertical deflection coil 4.
The present invention is not particularly limited to this, and even if it is provided between the insulating support frame 2 and the vertical deflection coil 4 or between the insulating support frame 2 and the horizontal deflection coil 3, the gist of the present invention is changed at all. Not something. However, when the deflection yoke manufacturing process is taken into consideration, the conventional deflection yoke manufacturing process is realized by providing the correction coil 6 between the ferrite core 5 and the vertical deflection coil 4 as shown in each of the above embodiments. Can be applied without much change. As a result, the manufacturing efficiency is high, and the characteristics of the deflection yoke can be sufficiently maintained.

(Third Embodiment) FIG. 3 shows a deflection yoke according to a third embodiment of the present invention in which a quadrupole magnetic field generating function is added to the deflection yoke of the first or second embodiment. .
FIG. 3 is a view showing the deflection yoke of the third embodiment mounted on, for example, the CRT display device shown in FIG. 5 and viewed from the neck portion 12 side of the CRT display device. In FIG. 3, two further magnetic field generating coils 21 and 22 are arranged in the horizontal direction in the drawing behind the neck side end 2b of the insulating support frame 2 of the deflection yoke 1 of the first or second embodiment. I have. That is, the magnetic field generating coils 21 and 22 are
It is arranged in the same direction as the electron beam arrangement direction of the electron gun 15 arranged in the neck portion 12 of the display device. The magnetic field generating coils 21 and 22 are configured by winding coils so as to generate magnetic fields in opposite directions around an “I” -shaped core. As a result, a quadrupole magnetic field as shown by a broken line 23 in the figure is generated. appear. This quadrupole magnetic field is
And horizontal lines of the cross hatch generated by the correction coils 6, 6a and 6b provided in the deflection yoke 1 in the second embodiment and additionally generated by a magnetic field in the tube axis direction for correcting the raster rotation of the image. Correct misconvergence that opens up and down.

(Fourth Embodiment) As means for generating a quadrupole magnetic field for correcting such a horizontal line misconvergence, magnetic field generating coils 25 and 26 are used as in a fourth embodiment shown in FIG. The electron beams may be arranged in a direction perpendicular to the arrangement direction. Alternatively, the magnetic field generating coils may be arranged at four positions in the same direction and the direction perpendicular to the arrangement direction of the electron beams (four positions in the vertical, horizontal, and right directions with respect to the electron gun). Further, the shape of each core of the magnetic field generating coils 21, 22, 24, 25 is not limited to the "I" shape, and the same effect can be obtained even if the shape is "U", "E", or "O" shape.

[0020]

As described above, according to the present invention, since the correction coil for generating the magnetic field for correcting the raster rotation of the image is provided inside the ferrite core, the special coil for fixing the correction coil is provided. No means such as a support frame protruding in an arm shape is required, and the outer shape of the deflection yoke is not increased. Further, since the distance between the correction coil and the electron beam is short, the efficiency of the correction coil is increased, and the number of turns of the coil and the DC current flowing through the coil can be reduced. Therefore, the cost is reduced, and when assembling as a CRT display device, no special consideration is required for the design of the housing and the like. In addition, since the correction coil is provided between the vertical deflection coil and the ferrite core, between the vertical deflection coil and the insulating support frame, or between the horizontal deflection coil and the insulating support frame, the outer shape of the deflection yoke is reduced. May be maintained at substantially the same size as those without. Further, by spirally winding the correction coil inside the ferrite core, the conventional ferrite core can be used as it is without special processing.
Also, depending on the thickness and the number of turns of the correction coil, the correction coil may not need to be provided on the entire inner surface of the ferrite core, and may be provided near the first end or the second end of the insulating support frame. Even if it is wound in an annular shape, a correction magnetic field in the tube axis direction can be generated similarly. Similarly, even if the correction coil is divided into two and wound in an annular shape inside the ferrite core and near the first end and the second end of the insulating support frame, the correction coil is similarly corrected in the tube axis direction. A magnetic field can be generated.
Further, the voltage is applied to a correction coil (first correction coil) provided near the first end of the insulating support frame and a correction coil (second correction coil) provided near the second end. By changing the direction and magnitude of the direct current to be generated and making the directions of the generated magnetic fields different from each other, the first correction coil corrects the raster rotation of the image, and the second correction coil generates the image. The magnetic field can correct the disturbance of three beam concentrations on the screen, which is additionally generated by the tube axis magnetic field generated by the first correction coil, so-called convergence disturbance. Further, a quadrupole magnetic field generating means is provided near the second end of the insulating support frame, and a quadrupole magnetic field is generated in a plane perpendicular to the tube axis of the cathode ray tube. Misconvergence in which the horizontal line of the crosshatch opens up and down, which is additionally generated by the magnetic field in the tube axis direction to correct the raster rotation of the image, can be corrected. Further, by constituting the quadrupole magnetic field generating means with at least one set of coils provided symmetrically with respect to the tube axis of the cathode ray tube, the structure is simple and the efficiency of magnetic field generation can be increased.

[Brief description of the drawings]

FIG. 1 is a partially broken side view showing a configuration of a first embodiment of a deflection yoke according to the present invention.

FIG. 2 is a partially broken side view showing the configuration of a deflection yoke according to a second embodiment of the present invention.

FIG. 3 is a rear view showing the configuration of a third embodiment of the deflection yoke according to the present invention.

FIG. 4 is a rear view showing the configuration of a fourth embodiment of the deflection yoke according to the present invention.

FIG. 5 is a partially broken plan view showing a configuration of a general CRT display device.

[Explanation of symbols]

 1: Deflection yoke 2: Insulating support frame 3: Horizontal deflection coil 4: Vertical deflection coil 5: Ferrite core 6: Correction coil

Continuing from the front page (72) Inventor Masanobu Honda 1-1, Sachimachi, Takatsuki-shi, Osaka Prefecture Inside Matsushita Electronics Corporation (72) Inventor Asato Aoki 1-1, Sachimachi, Takatsuki-shi, Osaka Matsushita Electronics (56) References JP-U 3-37743 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01J 29/76

Claims (3)

(57) [Claims] 1. A first cathode ray tube located on a screen side of a cathode ray tube.
A hollow insulating support frame having an end portion and a second end portion having an outer diameter smaller than the first end portion located on the neck portion side of the cathode ray tube, and provided inside the insulating support frame. A horizontal deflection coil, a vertical deflection coil provided outside the insulating support frame, a ferrite core provided outside the vertical deflection coil, and a tube axis direction of the cathode ray tube provided inside the ferrite core. And a correction coil for generating a magnetic field , wherein the correction coil is a ferrite.
Spirally wound uniformly over almost the entire inside of the core
It has been that the deflection yoke. 2. The deflection yoke according to claim 1, wherein the correction coil is provided between the vertical deflection coil and the ferrite core. 3. A cathode ray tube using the deflection yoke according to claim 1 .