JPH09213238A - Cathode ray tube device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily and effectively restrain the occurrence of leaked AC electric fields caused by a deflection device. SOLUTION: The cathode ray tube device is equipped with a deflection device 8, a reversed electric field generating device 34 generating voltage in reversed polarity wave form while being synchronized with the wave form of horizontal deflection voltage to be applied to a horizontal deflection coil, and with a reversed electric field compensation electrode 33 to which the aforesaid voltage in a reversed polarity wave form is applied. In this case, in the reversed electric field generating device 34, an auxiliary coil 39 in which horizontal deflection current flows, and a reversed polarity voltage wave form generating coil 40 which is connected with the reversed electric field compensation electrode at one end, and with the earth at the other end, are wound over a same core 37, and the core is so formed as to be changed in position with respect to the auxiliary coil 39 and the reversed polarity voltage wave form generating coil 40.

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, and more particularly to a cathode ray tube device that suppresses a leakage electric field generated from an electromagnetic deflection device that deflects an electron beam.

[0002]

2. Description of the Related Art In recent years, OA equipment has been remarkably developed and has become so familiar that it is used not only in offices but also in homes. With the spread of the OA equipment, the technology of shielding the leaked electromagnetic wave and the leaked electromagnetic field from the electronic equipment is becoming more important in terms of preventing noise of the electronic equipment and preventing the influence of electromagnetic waves on the human body. Especially in Northern Europe, the permissible value is shown and the standard is spreading because of concern about the influence of AC magnetic field and AC electric field on the human body.

As the OA equipment, there is widely used an image display device using a cathode ray tube device which displays an image by deflecting an electron beam emitted from an electron gun by a magnetic field generated by a deflecting device and scanning a phosphor screen. Used.

As shown in FIG. 6, a cathode ray tube device generally has an envelope including a glass face portion 1 and a funnel portion 2, and a phosphor screen 3 is formed on the inner surface of the face portion 1 to form a funnel. The cathode ray tube 6 in which the electron gun 5 is arranged in the neck 4 of the part 2 and its funnel part 2
And a deflection device 8 for generating a magnetic field for deflecting the electron beam 7 emitted from the electron gun 5. From such a cathode ray tube device, a leak electromagnetic wave or a leak electromagnetic field is generated, and it is desired to shield the leak electromagnetic wave or the leak electromagnetic field.

Generally, there are the following methods for shielding leaked electromagnetic waves and leaked electromagnetic fields emitted from a cathode ray tube device. (A) Electrostatic shielding that prevents the lines of electric force from going out by using a material with low electrical resistance. (B) Using a metal material with low resistance, make sure that current flows through this metal material with low resistance. Electromagnetic shielding to be used (C) Magnetic shielding that uses magnetic material with low electric resistance as a shielding conductor to confine the magnetic field lines inside

Specifically, (a) a method of covering the deflection device with a metal plate such as stainless steel (b) a method of covering the top, bottom, left and right and the rear part of the cathode ray tube device with a metal plate etc. (c) a phosphor screen of the cathode ray tube This is done by providing a transparent electromagnetic wave shielding plate on the front of the building.

However, the method of covering the deflecting device and the cathode ray tube device with a metal plate or the like, or the method of forming a transparent electromagnetic wave shielding plate, for example, a coating film made of a conductive oxide, on the front surface of the cathode ray tube causes a cost problem. Becomes Further, these methods have a problem that the AC magnetic field leaking from the front surface of the cathode ray tube cannot be sufficiently shielded.

As a method for solving this problem, (d) a method of arranging a magnetically permeable ring on the phosphor screen side of the deflecting device (e) a magnetic field in the direction opposite to the leakage magnetic field is caused by flowing a current synchronized with the deflection current. There is a method of compensating for a leakage magnetic field using a compensation coil generated.

However, not only the magnetic field but also the AC electric field leaks from the cathode ray tube device, and recently, the influence of the AC electric field on the human body has been a concern. In order to shield this leaking AC electric field, the entire cathode ray tube device may be covered with a metal plate or the like, but this is a problem in terms of cost and there is no method capable of obtaining a sufficient effect with a simple method.

However, recently, it has been clarified that the leakage AC electric field of the cathode ray tube device is generated mainly from the horizontal deflection coil of the deflection device in synchronization with the horizontal deflection voltage applied to the horizontal deflection coil. Japanese Patent Application Laid-Open No. 5-207404 discloses a means for suppressing an AC electric field having a polarity opposite to that of the AC leakage electric field generated in synchronization with the AC electric field.

As shown in FIG. 6, this leakage AC electric field suppressing means is a reverse voltage supply unit 1 in which two sets of coils 10 and 11 are wound around a cathode 9 and a link-shaped core 9 which is a closed magnetic circuit.
2 (reverse electric field generator), and a reverse electric field compensating electrode 13 is installed in the vicinity of the face portion 1 of the cathode ray tube 5, and the coil 10 of the reverse voltage supply unit 12 is used as an input side coil and the coil 11 as an output side coil. 10 is connected so that a horizontal deflection current flows, one end of the coil 11 is connected to the reverse electric field compensation electrode 13, and the other end is grounded. With this means, when a horizontal deflection current flows through the input side coil 10, a magnetic flux is generated in the core 9 and an induced electromotive force is generated in the output side coil 11. The direction of the electromotive force generated in the coil 11 is determined by the direction of the magnetic flux generated in the core 9. In this case,
When the waveform of the horizontal deflection voltage 14 is positive, the waveform of the voltage 15 generated in the output side coil 11 is negative, that is, the voltage of the opposite polarity is generated, whereby the reverse electric field compensation electrode 13 An electric field of opposite polarity is generated, and the electric field of opposite polarity suppresses the leakage AC electric field generated from the deflecting device.

[0012]

As described above, the cathode ray tube is used as means for suppressing the AC electric field leaking from the cathode ray tube apparatus, particularly the leaking AC electric field generated from the horizontal deflection coil of the deflecting apparatus, which is the main source of the AC electric field. The tube is provided with a reverse voltage supply unit in which two sets of coils are wound around a link-shaped core, and a reverse electric field compensation electrode is provided near the face portion of the cathode ray tube, and one input side coil of the reverse voltage supply unit is placed horizontally. Connect so that the deflection current flows, connect one end of the other output side coil to the reverse electric field compensation electrode, and ground the other end.When the horizontal deflection current flows through the input side coil, the reverse polarity is generated in the output side coil. Electric power is generated, and by the electromotive force of the opposite polarity, an electric field having a polarity opposite to that of the leakage AC electric field generated by the deflecting device is generated from the reverse electric field compensating electrode to suppress the leakage AC electric field generated by the deflecting device. There has been proposed.

However, with this means, it is necessary to adjust the number of windings of the two coils according to the magnitude of the leakage AC electric field. Further, this adjustment must be performed in a state where the cathode ray tube device is incorporated in the image display device. For that purpose, a cathode ray tube device of the same standard is desired for various image display devices. There is a problem that it is extremely difficult to construct a cathode ray tube device.

The present invention has been made to solve the above problems, and the magnitude of the reverse polarity voltage generated from the reverse electric field generating device for suppressing the leakage AC electric field generated from the deflecting device is variable. It is an object of the present invention to configure a cathode ray tube device that can easily and effectively suppress the leakage AC electric field generated from the deflecting device.

[0015]

A deflection device having at least a cathode ray tube, a horizontal deflection coil for deflecting an electron beam emitted from an electron gun of the cathode ray tube, and a horizontal deflection voltage applied to the horizontal deflection coil. In a cathode ray tube device including a reverse electric field generator that generates a voltage of a reverse polarity waveform in synchronism with a waveform and a reverse electric field compensation electrode that is supplied with a voltage of a reverse polarity waveform generated by the reverse electric field generator, a reverse electric field The generator is wound around an auxiliary coil through which a horizontal deflection current flows through the same core and a reverse polarity voltage waveform generating coil with one end connected to the reverse electric field compensation electrode and the other end grounded. The position of the waveform generating coil was variable.

Further, the reverse electric field compensating electrode is arranged near the face portion of the cathode ray tube.

[0017]

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

FIG. 1 shows a cathode ray tube device which is one form thereof. This cathode ray tube device is made of a glass including a substantially rectangular glass face portion 1 having a skirt portion 31 provided around the effective portion 30 and a funnel-shaped glass funnel portion 2 connected to the skirt portion 31. A phosphor screen (not shown) is provided on the inner surface of the face portion 1 having an envelope.
And a cathode ray tube 6 in which an electron gun (not shown) is arranged in the neck 4 of the funnel portion 2 and the outer periphery of the funnel portion 2 near the boundary between the large diameter portion 32 and the neck 4. , The electron beam emitted from the electron gun 5 is horizontal,
A deflecting device 8 for vertically deflecting and a reverse electric field which is disposed on the skirt portion 31 close to the effective portion 30 of the face portion 1 and which generates an electric field having a polarity opposite to that of the leakage AC electric field generated from the deflecting device 8. It comprises a compensation electrode 33 and a reverse electric field generator 34 connected to the reverse electric field compensation electrode 33.

The deflection device 8 includes a horizontal deflection coil that generates a horizontal deflection magnetic field that horizontally deflects the electron beam 7 emitted from the electron gun 5, and a vertical deflection coil that generates a vertical deflection magnetic field that vertically deflects the electron beam 7. Have and. Generally, such a deflection device 8 includes a saddle / saddle type in which a horizontal deflection coil is a pair of upper and lower saddle type deflection coils, a vertical deflection coil is a pair of left and right saddle type deflection coils, and a horizontal deflection coil is a pair of upper and lower saddle type deflection coils. A saddle / toroidal type (semi-toroidal type) in which a coil and a vertical deflection coil are a pair of upper and lower toroidal deflection coils is often used. The horizontal and vertical deflection coils of the deflecting device 8 are supplied with a voltage having a waveform that changes in a predetermined cycle from a deflection drive circuit (not shown). Especially, the horizontal deflection coil usually has a voltage of several hundred to 1 kV. The pulsed waveform voltage of is supplied.

As described above, it is known that an AC electric field leaks from the cathode ray tube device, and this leaking AC electric field is mainly generated from the horizontal deflection coil of the deflecting device.
The generation of the leakage AC electric field from the horizontal deflection coil causes the horizontal deflection coil to be supplied with a deflection voltage that is time-varying in synchronization with the horizontal deflection frequency. This is because the electric field occurs from the low voltage side to the low voltage side, and this potential is also higher than the ground potential, that is, above the ground, so that a fluctuating electric field is generated between the ground and the ground.

The reverse electric field generator 34 and the reverse electric field compensating electrode 33 are for suppressing such a leakage AC electric field.

As shown in FIG. 1 (b), the reverse electric field generator 34 has a cylindrical mold 37 having flange portions 36 at both ends and an intermediate portion, and a screw in the direction of the central axis of the mold 37. The mold 37, that is, the shaft of the mold 37 via the screw-shaped core 38 forming a closed magnetic circuit, which is provided in a variable position with respect to the auxiliary coil and the reverse voltage waveform generating coil described below, and the intermediate flange portion 36. The auxiliary coil 39 and the reverse voltage waveform generating coil 40 are wound adjacent to each other in the direction. Both ends of the one auxiliary coil 39 are connected so that a horizontal deflection current flowing through the horizontal deflection coil of the deflecting device 8 is supplied thereto, and one end of the other reverse voltage waveform generating coil 40 is connected to the reverse electric field compensation electrode 33. And the other end is grounded.

In such a reverse electric field generating device 34, when a horizontal deflection current flows through the auxiliary coil 39, the core 3 of the screw shape is formed.
8, a magnetic flux is generated, and an induced electromotive force is generated in the reverse voltage waveform generating coil 40. The direction of this induced electromotive force is determined by the direction of the magnetic flux generated in the core 37. When the waveform of the horizontal deflection voltage 41 flowing in the auxiliary coil 39 is positive, the waveform of the voltage 42 generated in the reverse voltage waveform generating coil 39 is A negative voltage, that is, a voltage with a reverse polarity waveform is generated. Moreover, in the reverse electric field generator 34, the reverse voltage waveform generating coil 40 is adjusted by rotating the screw-shaped core 38 screwed into the mold 37 and adjusting the positions with respect to the auxiliary coil 39 and the reverse voltage waveform generating coil 40. It is possible to change the magnitude of the induced electromotive force generated in the.

Therefore, for example, as shown in FIG. 2A, the leakage electric field 4 generated from the horizontal deflection coil of the deflection device 4
When the waveform of 4 is large, as shown in (c), by increasing the insertion amount of the core 38 into the mold 37, the amount of magnetic flux generated in the core 38 increases, and as shown in (b), The waveform of the reverse polarity voltage 42 generated in the reverse voltage waveform generating coil 40 can be increased. Further, as shown in FIG. 3A, when the waveform of the leakage electric field 44 generated from the horizontal deflection coil of the deflection device is small, as shown in FIG. 3C, the insertion amount of the core 38 into the mold 37 is reduced. As a result, the amount of magnetic flux generated in the core 38 decreases, and as shown in FIG.
It is possible to reduce the waveform of the voltage 42 having the opposite polarity generated in the above.

2 (a), 2 (b) and 3
The broken lines shown in (a) and (b) are ground potentials.

Therefore, according to the reverse electric field generating device 34, the leakage electric field 44 generated from the horizontal deflection coil of the deflecting device 8 has the opposite polarity generated from the reverse electric field compensation electrode 33 connected to the reverse voltage waveform generating coil 40. It can be suppressed by the electric field. Moreover, a cathode ray tube device having such a reverse electric field generating device 34 and a reverse electric field compensating electrode 33 uses the reverse electric field generating device 34 of the same configuration, and after adjusting the cathode ray tube device into the image display device, A leakage electric field 44 generated from the horizontal deflection coil of the deflection device 8 easily and effectively
The effect of being able to suppress

In the above embodiment, a pair of auxiliary coil and reverse voltage waveform generating coil are provided adjacent to each other in the axial direction of the cylindrical mold via the flange portion provided in the intermediate portion of the cylindrical mold. The reverse electric field generating device provided has been described, but the reverse electric field generating device is as shown in FIG.
In addition to the both ends of the cylindrical mold 37, two flange portions 36 are provided in the intermediate portion, and the auxiliary coil 39 is provided in series between the flange portion 36 at each end portion and the flange portion 36 at the intermediate portion.
a and 39b are wound around, and two intermediate flange portions 3
A structure in which a reverse voltage waveform generating coil 40 is wound between 6 may be used. Further, as shown in (b), the auxiliary coil 39 and the reverse voltage waveform are generated in a cylindrical mold 37 having flange portions 36 at both ends. Auxiliary coil 39 and reverse voltage waveform generating coil 40, such as a structure in which the coil 40 and the coil 40 are overlapped and wound.
On the other hand, if the core 38 has a variable position, it can be similarly used.

[0028]

The cathode ray tube is provided with a deflecting device, a reverse electric field generating device for generating a voltage having a reverse polarity waveform in synchronization with the waveform of the horizontal deflection voltage applied to the horizontal deflection coil, and the voltage having the reverse polarity waveform. In a cathode ray tube device equipped with a reverse electric field compensating electrode, a reverse electric field generator is used to generate a reverse polarity voltage waveform in which an auxiliary coil through which a horizontal deflection current flows in the same core and one end is connected to the reverse electric field compensating electrode and the other end is grounded. When the coil is wound around and the core is formed in a variable position with respect to the auxiliary coil and the reverse polarity voltage waveform generating coil, it is generated from the horizontal deflection coil of the deflection device which is the main source of the leakage AC electric field of the cathode ray tube device. The leakage AC electric field can be suppressed by the electric field of opposite polarity generated from the reverse electric field compensation electrode. Moreover, the reverse electric field generator having the same configuration is used, and after the cathode ray tube device is incorporated in the image display device, the reverse electric field generator is adjusted to easily and effectively suppress the leakage electric field generated from the horizontal deflection coil of the deflection device. can get.

[Brief description of drawings]

FIG. 1 (a) is a diagram showing a configuration of a cathode ray tube device according to an embodiment of the present invention, and FIG. 1 (b) is a diagram showing a configuration of a reverse electric field generating device thereof.

2 (a) to 2 (c) are explanatory views in the case where the leakage electric field generated from the horizontal deflection coil of the deflecting device is large, and the leakage electric field is suppressed by the reverse polarity voltage generated from the reverse electric field generating device. Is.

3 (a) to 3 (c) are explanatory views in the case where the leakage electric field generated from the horizontal deflection coil of the deflecting device is small and the leakage electric field is suppressed by the voltage of the reverse polarity generated from the reverse electric field generating device. Is.

FIG. 4 (a) and FIG. 4 (b) are diagrams showing different configurations of the reverse electric field generator.

FIG. 5 is a diagram showing a configuration of a normal cathode ray tube device.

FIG. 6 is a diagram showing a configuration of a known cathode ray tube device configured to suppress a leakage electric field.

FIG. 7 is a diagram for explaining a configuration of a reverse voltage supply unit of the known cathode ray tube device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Face part 6 ... Cathode ray tube 8 ... Deflection device 33 ... Reverse electric field compensation electrode 34 ... Reverse electric field generator 37 ... Mold 38 ... Core 39 ... Auxiliary coil 40 ... Reverse voltage waveform generating coil

Claims (2)

[Claims] 1. A cathode ray tube, a deflection device having at least a horizontal deflection coil for deflecting an electron beam emitted from an electron gun of the cathode ray tube, and a horizontal deflection voltage waveform applied to the horizontal deflection coil. In a cathode ray tube device comprising a reverse electric field generator for generating a voltage of a reverse polarity waveform and a reverse electric field compensation electrode supplied with a voltage of a reverse polarity waveform generated by the reverse electric field generator, the reverse electric field generator is An auxiliary coil through which a horizontal deflection current flows in the same core and a reverse polarity voltage waveform generating coil whose one end is connected to the reverse electric field compensation electrode and whose other end is grounded are wound,
A cathode ray tube device, wherein the core is formed in a variable position with respect to the auxiliary coil and the reverse polarity voltage waveform generating coil. 2. The cathode ray tube device according to claim 1, wherein the reverse electric field compensating electrode is arranged in the vicinity of the face portion of the cathode ray tube.