JPH06283114A - Cathode-ray tube device - Google Patents

Abstract

PURPOSE:To simply and properly correct the leakage magnetic field of a deflection yoke by providing compensation magnetic field alignment conducting loops made of short circuit loops including impedance elements magnetically coupled with the compensation magnetic field generated by compensation coils. CONSTITUTION:A pair of upper and lower leakage flux compensation coils 35 with the fine alignment function are arranged near the fluorescent screen side crossover section 32a of horizontal deflection coils 30. Each of the coils 35 is constituted of a compensation coil 38 made of ferrite cores 36 and coils 37 and a compensation magnetic field alignment conducting loop 42 including coils 40 and a variable inductance 41. The coil 38 generates the magnetic flux outside the region of the leakage flux of the horizontal deflection main magnetic flux in the opposite direction to the leakage flux not contributing to the deflection of the direct electron beam generated mainly from the crossover section 32a near the crossover section 32a of the coils 30. The coil 38 generates the magnetic flux in the opposite direction to the leakage flux of the horizontal deflection main magnetic flux at the position apart from the coil 38. The magnetic field generated by a deflection yoke can be properly corrected.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cathode ray tube device equipped with a deflection yoke, and a cathode ray tube device having a compensation coil for reducing a leakage magnetic field of the deflection yoke which leaks to the outside of the cathode ray tube.

[0002]

2. Description of the Related Art Recently, the influence of a leakage magnetic field on a human body has been taken up mainly in Northern Europe, and a movement for regulating the leakage magnetic field has been activated. In the MPR (SSI) standard for this leakage magnetic field, 5 Hz to 2 kHz and 2 kHz to 400 kHz
Is a problem, and in the cathode ray tube device, it is necessary to reduce the leakage flux of the magnetic flux generated from the deflection yoke that does not contribute to the deflection of the electron beam emitted from the electron gun to a considerable level. . Of the above magnetic fields, the magnetic field of 5 Hz to 2 kHz corresponds to the magnetic field generated from the vertical deflection coil of the deflection yoke, and the magnetic field of 2 kHz to 400 kHz corresponds to the magnetic field generated from the horizontal deflection coil.

The deflection yoke shown in FIG. 6 is a general deflection yoke mounted on a cathode ray tube such as a color picture tube.
Inside the separator 1, a pair of upper and lower saddle type horizontal deflection coils 2 that generate a magnetic field for horizontally deflecting an electron beam emitted from an electron gun of a cathode ray tube are arranged with a horizontal axis (X axis) interposed therebetween. Further, a pair of left and right saddle type vertical deflection coils 3 for generating a magnetic field for vertically deflecting an electron beam emitted from an electron gun is arranged outside the separator 1 with a vertical axis (Y axis) interposed therebetween. A conical cylindrical core 4 is arranged so as to surround the outer circumference of the deflection coil 3.

In this deflection yoke, most of the magnetic flux generated from the horizontal deflection coil 2 is confined in the inner space 5 of the deflection yoke by the core 4 surrounding the outer periphery of the vertical deflection coil 3 outside the separator 1, but a part of it is contained. Is radiated as a leakage magnetic flux to the outside of the deflection yoke. FIG. 7 shows the leakage state of the horizontal deflection magnetic field formed by the horizontal deflection coil 2. Normal horizontal deflection main magnetic flux 6 leakage magnetic flux 7
Is spread at an opening angle of 30 to 40 ° shown by curves 8a and 8b, and a leakage magnetic flux 10 is generated above and below the front crossover 9 of the horizontal deflection coil 2 in the direction opposite to the main magnetic flux 6. .

The leakage state of the vertical deflection magnetic field formed by the vertical deflection coil 3 is distributed in substantially the same manner except that the directions of the magnetic flux differ by 90 °.

As a means for compensating for such a leakage magnetic field, Japanese Patent Application Laid-Open No. 62-64024 discloses a horizontal deflection coil 2 via a core 4 outside the saddle type horizontal deflection coil 2 as shown in FIG. Leakage magnetic field compensation coil with almost the same shape as
12 is arranged and a part of the current flowing in the horizontal deflection coil 2 is reversed so that a magnetic flux in the direction indicated by the arrow 14 opposite to the direction of the main magnetic flux of the horizontal deflection coil 2 indicated by the arrow 13 is generated. It is shown that the leakage flux of the horizontal deflection coil 2 is reduced by flowing in phase.

However, in the compensating coil 12, since the intensity of the compensating magnetic field generated is adjusted by the number of turns of the coil, it is difficult to finely adjust the magnetic field intensity.

As a means capable of finely adjusting the compensation magnetic field, Japanese Patent Laid-Open No. 62-82633 discloses a variable inductance in parallel with a compensation coil 12 connected to a horizontal deflection coil 2 as shown in FIG. It is shown that the energization amount adjusting device 16 composed of is provided to shunt adjust the horizontal deflection current flowing in the compensation coil 12.

However, when the energization amount adjusting device 16 is provided in parallel with the compensating coil 12 as described above, an induced current is generated in a closed circuit formed by the variable inductance and the induced electromotive force between the compensating coil 12 due to the difference in the induced electromotive force. Occurs. Further, in this adjusting means, the shunt circuit board must be provided on the deflection yoke, which makes the device complicated, which is not practical.

[0010]

As described above, as a means for suppressing the leakage magnetic flux generated from the deflection yoke of the cathode ray tube device in the related art, the horizontal deflection coil is almost provided outside the saddle type horizontal deflection coil via the core. There is an arrangement in which compensating coils of the same shape are arranged to reduce the leakage magnetic flux of the horizontal deflection coil. However, this compensating coil has a problem that it is difficult to finely adjust the strength of the magnetic field because the strength of the compensating magnetic field generated is adjusted by the number of turns of the coil.

As a means capable of finely adjusting the intensity of the compensation magnetic field, an energization amount adjusting device consisting of a variable inductance is provided in parallel with the compensation coil connected to the horizontal deflection coil to shunt the horizontal deflection current flowing through the compensation coil. There is something to do. However, when the energization amount adjusting device is provided in parallel with the compensation coil as described above, an induced current is generated in the closed circuit formed by the variable inductance and the induced electromotive force between the compensation coil and the compensation coil. In addition, since the shunt circuit board must be provided on the deflection yoke, there is a problem that the device becomes complicated.

The present invention has been made in view of the above problems, and the strength of the compensating magnetic field can be easily achieved without significantly changing the means for compensating the leakage magnetic field and without significantly complicating the circuit. It is an object of the present invention to configure a cathode ray tube device capable of changing

[0013]

A cathode ray tube is equipped with a deflection yoke for generating a magnetic field for horizontally and vertically deflecting an electron beam emitted from the electron gun, and the deflection yoke leaks outside the cathode ray tube. In a cathode ray tube device provided with a compensation coil for generating a compensation magnetic field for reducing a magnetic field by passing a deflection current flowing through a deflection yoke, the cathode ray tube device includes a closed loop including an impedance control element and is magnetically coupled to the compensation magnetic field generated by the compensation coil. A compensation magnetic field adjusting conductive loop is provided.

[0014]

As described above, when the compensation magnetic field adjustment conductive loop including the short circuit loop including the impedance control element magnetically coupled to the compensation magnetic field generated by the compensation coil is provided, the AC magnetic flux generated by the compensation coil adjusts the compensation magnetic field. The conductive electromotive loop is interlinked, and by this interlinkage, an induced electromotive force is generated in the compensation magnetic field adjusting conductive loop in a direction proportional to the time variation of the interlinking magnetic flux and compensating for this, and an induced current flows. As a result, an induced magnetic flux having a polarity that compensates the compensation magnetic flux generated by the compensation coil is generated. Further, the intensity of the compensation magnetic field can be increased or decreased by changing the inductance of the compensation magnetic field adjusting conductive loop by the impedance control element.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will now be described based on embodiments with reference to the drawings.

FIG. 1 shows a cathode ray tube device which is an embodiment of the present invention. The cathode ray tube in this apparatus is a color picture tube, and has an envelope composed of a panel 20 and a funnel-shaped funnel 21 integrally joined to the panel 20, and the panel is provided.
A phosphor screen 22 composed of a three-color phosphor layer that emits blue, green, and red is formed on the inner surface of the phosphor 20.
A shadow mask 23 having a large number of electron beam passage holes formed therein is mounted so as to face 22. On the other hand, in the neck 24 of the funnel 21, three electron beams 25B, 25G,
An electron gun 26 that emits 25R is arranged. Further, outside the boundary between the large diameter portion of the funnel 21 of this color picture tube and the neck 24, the three electron beam emitted from the electron gun 26 is emitted.
A deflection yoke 27 that generates a magnetic field that deflects 25B, 25G, and 25R horizontally and vertically is mounted.

The deflection yoke 27 is formed in a saddle-saddle type, and as shown in FIG. 2, is vertically symmetrically arranged inside the separator 29 with a horizontal axis interposed therebetween, and horizontally deflects the three electron beams. A pair of saddle-shaped horizontal deflection coils 30 that generate a horizontal deflection magnetic field and a vertical deflection magnetic field that is symmetrically arranged outside the separator 29 with a vertical axis (Y axis) interposed therebetween and that vertically deflects the above three electron beams. And a pair of saddle type vertical deflection coils 31 for generating. Crossover portions 32a and 32b are formed on the pair of horizontal deflection coils 30 on the side of the fluorescent screen and on the side of the opposite electron gun, respectively. Similarly, in the pair of vertical deflection coils 31, crossover portions 33a, 33a,
33b is formed. Further, on the outer circumference of the vertical deflection coil 31, the crossover portion 32 of the horizontal and vertical deflection coils 30 and 31 is provided.
A conical tube-shaped core 34 is arranged so as to surround the vertical deflection coil 31 while avoiding a, 32b, 33a and 33b.

Further, in this cathode ray tube device, a pair of upper and lower leakage magnetic field compensating coils 35 with a fine adjustment function are provided corresponding to the horizontal deflection coils 30 in the vicinity of the fluorescent screen side connecting line portion 32a of each horizontal deflection coil 30. It is arranged.

The leakage magnetic field compensation coil with each fine adjustment function
As shown in FIGS. 2 and 3, 35 is a compensation coil 38 including a rod-shaped ferrite core 36 and a coil 37 wound around the core 36, and is wound around the core 36 close to the coil 37. It comprises a coil 40 and a compensation magnetic field adjusting conductive loop 42 forming a closed loop including a variable inductance 41 (impedance control element) connected in series to the coil 40. The compensation coil 38 of this illustrated example is connected to the horizontal deflection coil 30 and has a structure in which a horizontal deflection current is supplied, but in addition, a current synchronized with the horizontal deflection current flowing in the horizontal deflection coil 30 is supplied. It may be a structure.

By the way, as described above, the horizontal deflection coil 30
When a compensating coil 38 connected to the horizontal deflection coil 30 is arranged near the fluorescent screen side crossover part 32a, the magnetic field is generated near the fluorescent screen side crossover part 32a of the pair of horizontal deflection coils 30. Occur in a concentrated manner. The magnetic flux is generated in the vicinity of the compensation coil 38, outside the region of the leakage magnetic flux of the horizontal deflection main magnetic flux, and mainly from the fluorescent screen side crossover portion 32a of the horizontal deflection coil 30 which does not contribute to the deflection of the direct electron beam. Occurs in the opposite direction and cancels the leakage magnetic flux. Further, at a position away from the compensation coil 38, a magnetic flux in the direction opposite to the leakage magnetic flux of the horizontal deflection main magnetic flux is generated to reduce the temporal change of the leakage magnetic flux, that is, the induced magnetic flux density dB / dT.

Moreover, in this cathode ray tube device, the compensation coil
Since the coil 40 of the compensation magnetic field adjusting conductive loop 42 is arranged close to the coil 38, the alternating magnetic flux generated by the compensation coil 38 is linked to the coil 40 by passing the horizontal deflection current.
As a result, as shown in FIG. 4B, corresponding to the AC magnetic flux φ generated by the compensation coil 38 shown in FIG. 4A, the interlinkage magnetic flux in the compensation magnetic field adjusting conductive loop 42 changes with time. And an induced electromotive force Vi in a direction proportional to and compensating for
The induced current li shown in FIG. 4 (c) flows and an induced magnetic flux φi is generated. As a result, the magnetic flux φ generated by the compensation coil 38 is induced by the compensation magnetic field adjusting conductive loop 42.
Is compensated by, the inductance of the compensation coil 38 is reduced, and the magnetic flux φ generated by the compensation coil 38 is reduced.

Further, the variable inductance 41 can change the inductance of the compensation magnetic field adjusting conductive loop 42, thereby increasing or decreasing the intensity of the compensation magnetic field. Of the magnetic flux generated from the deflection yoke of the cathode ray tube device, the electron beam It is possible to easily and favorably reduce the leakage magnetic flux that does not contribute to the deflection.

In the above embodiment, the compensation magnetic field adjusting conductive loop coil is wound around the rod-shaped ferrite core of the compensation coil. However, as another configuration, as shown in FIG. A lead wire 44 from a power supply (not shown) of a horizontal deflection current flowing through the horizontal deflection coil 30, a compensation magnetic field adjusting conductive loop 42 forming a closed loop including a compensation coil 38 and a variable inductance 41 is wound on the lead wire 44.
The leakage magnetic field of the horizontal deflection coil 30 is compensated by the induced magnetic flux generated in the compensation coil 38 by causing an induced electromotive force in the compensation coil 38 due to the change in the magnetic flux in the ferrite core 36 due to the leakage magnetic field. You may. In this case, the compensation magnetic field can be finely adjusted by the variable inductance 41 of the compensation magnetic field adjustment conductive loop 42.

In the above embodiment, in order to reduce the leakage magnetic flux generated from the horizontal deflection coil of the deflection yoke, the leakage magnetic field compensation coil with the fine adjustment function is arranged corresponding to the horizontal deflection coil. The function of the stray magnetic field compensation coil can be applied to reduce the stray magnetic flux generated from the vertical deflection coil.

In this case, when the vertical deflection coil is a saddle type as in the deflection yoke shown in the above embodiment, the vertical deflection coils are arranged on the left and right sides with the vertical axis sandwiched therebetween. The leakage magnetic field compensation coil with the fine adjustment function having the same configuration as the leakage magnetic field compensation coil with the fine adjustment function may be arranged close to the crossover portion on the phosphor screen side. In this case, the coil is supplied with a vertical deflection current flowing through the vertical deflection coil or a current synchronized with the vertical deflection current.

Further, leakage magnetic field compensating coils with a fine adjustment function are arranged on the upper, lower, left and right sides of the deflection yoke so as to reduce the leakage magnetic flux generated from the horizontal deflection coil and the leakage magnetic flux generated from the vertical deflection coil. Is also optional.

[0027]

When a compensation coil and a compensation magnetic field adjusting conductive loop including a closed loop including an impedance control element magnetically coupled to the compensation magnetic field generated by the compensation coil are provided, the AC magnetic flux generated by the compensation coil is generated by the compensation magnetic field. Interlinking with the adjusting conductive loop, and due to this interlinking, an induced electromotive force is generated in the compensating magnetic field adjusting conductive loop in a direction proportional to the time fluctuation of the interlinking magnetic flux and compensating for this, and an induced current flows. As a result, an induced magnetic flux having a polarity that compensates the compensation magnetic flux generated by the compensation coil is generated. In addition, by changing the inductance of the compensation magnetic field adjusting conductive loop by the impedance control element, it is possible to increase or decrease the compensation magnetic field strength. Can be reduced easily and satisfactorily.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a cathode ray tube device in which a cathode ray tube according to an embodiment of the present invention is a color picture tube.

FIG. 2 is a diagram showing an arrangement of a leakage magnetic field compensation coil with a fine adjustment function for the deflection yoke.

FIG. 3 is a circuit diagram showing a configuration of a leakage magnetic field compensation coil with the fine adjustment function.

4 (a) to 4 (c) are diagrams for explaining the action of a compensation magnetic field adjusting conductive loop in a leakage magnetic field compensating coil with a fine adjustment function.

FIG. 5 is a circuit diagram showing a different configuration of a leakage magnetic field compensation coil with a fine adjustment function.

FIG. 6 is a diagram showing a configuration of a deflection yoke attached to a cathode ray tube such as a color picture tube.

FIG. 7 is a diagram showing a leakage state of a magnetic field generated by the horizontal deflection coil.

FIG. 8 is a diagram showing a configuration of a conventional leakage magnetic field compensation coil for compensating for the leakage magnetic field.

FIG. 9 is a circuit diagram showing a configuration of a conventional leakage magnetic field compensation coil capable of finely adjusting a compensation magnetic field.

[Explanation of symbols]

 22 ... Phosphor screen 25B, 25G, 25R ... 3 electron beam 26 ... Electron gun 27 ... Deflection yoke 30 ... Horizontal deflection coil 31 ... Vertical deflection coil 32a ... Crossover part 33a of horizontal deflection coil on the phosphor screen side ... Vertical deflection coil Phosphor screen side crossover part 34 ... Core 35 ... Leakage magnetic field compensation coil with fine adjustment function 37 ... Coil 38 ... Compensation coil 40 ... Coil 41 ... Variable inductance 42 ... Compensation magnetic field adjustment conductive loop

Claims (1)

[Claims] 1. A cathode ray tube having an electron gun for emitting an electron beam for scanning a phosphor screen, and a magnetic field mounted on the cathode ray tube for deflecting the electron beam emitted from the electron gun in horizontal and vertical directions. A deflection yoke that is generated, a compensation coil that generates a compensation magnetic field that reduces the leakage magnetic field of the deflection yoke that leaks to the outside of the cathode ray tube by passing a deflection current, and a closed loop that includes an impedance control element. And a compensating magnetic field adjusting conductive loop magnetically coupled to the compensating magnetic field.