JPH0590797U - Cathode ray tube - Google Patents

Abstract

(57) [Abstract] [Purpose] Without increasing the types of exterior specifications of cathode ray tubes,
A measure for leaking alternating electric field from the deflection yoke provided in the cathode ray tube can be added at any time. [Structure] A funnel-shaped insulating sheet 10 having a conductive film 11 for electric field shielding on the inner surface is fixed to a cone of a funnel, and a deflection yoke is attached around the funnel-shaped insulating sheet 10. [Effect] Even if the type of exterior specification of the cathode ray tube is not differentiated between those for alternating electric field countermeasures and those for which it is not, only by providing the funnel-shaped insulating sheet having the conductive film for electric field shielding on the inner surface. There is an effect that it is possible to take measures against the alternating electric field.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a cathode ray tube provided with measures for reducing an alternating electric field leaking forward from a deflection yoke provided in the cathode ray tube.

[0002]

[Prior Art]

 FIG. 4 is a block diagram of a conventional cathode ray tube. In the figure, the funnel 1 comprises a funnel body 1c having a neck portion 1a, a cone portion 1b, and a high-pressure anode button 1d. The joint between the neck portion 1a and the cone portion 1b is called a neck seal line 1e. A face panel 2 is frit-bonded to the front of the funnel 1. The glass bulb 20 is configured as described above. An electron gun 3 is sealed in the neck portion 1a. An explosion-proof band 4 for ensuring explosion-proof characteristics is wound around the outer peripheral surface of the panel 2, and mounting ears 4a for suspending the glass valve 20 on a chassis (not shown) are provided at four corners. .. Further, a silicon resin film 5 for insulation is formed around the high pressure anode button 1d provided on the funnel body 1c. Further, a conductive film 6 for adding capacitance is provided on the outer surface of the funnel main body 1c. This conductive film 6 is usually formed by applying graphite. In addition, 28 is a straight line parallel to the neck portion 1a and indicates the tube axis of the cathode ray tube.

As shown in FIG. 6, a deflection yoke 9 for deflecting an electron beam is attached to the cathode ray tube configured as described above at a position between the cone portion 1b and the neck portion 1a. ing. As shown in FIG. 7, the deflection yoke 9 is composed of a horizontal deflection coil 9a, a vertical deflection coil 9b, and a deflection yoke body 9c.

Next, the operation will be described. When an electron beam is emitted from the electron gun 3 sealed in the neck portion 1a, the emitted electron beam is moved by the horizontal deflection coil 9a and the vertical deflection coil 9b of the deflection yoke 9 in a predetermined amount in the horizontal and vertical directions. The phosphor film formed on the inner surface of the face panel 2 after being deflected is scanned to display a desired image. In the configurations described so far, when the electron beam is deflected, no measure is taken to shield the alternating electric field radially generated around the deflection yoke, which is directed toward the front, and is harmful to the human body. There is a problem that the alternating electric field is transmitted through the funnel and face panel of the cathode ray tube and leaks from the front of the cathode ray tube. In consideration of the above-mentioned problems, as shown by reference numeral 7 in FIG. 4, a deflection that leaks from the front surface of the face panel through the funnel to a predetermined area from the cone portion where the deflection yoke of the funnel is fitted to the neck portion. An electric field shield conductive film 7 for reducing the alternating electric field of the yoke is provided. The conductive film 7 is also formed by applying graphite, like the conductive film 6 for adding capacitance. The conductive film 7 is formed on the outer surface of the cone portion from the region having a diameter larger than the opening diameter of the horizontal deflection coil of the deflection yoke to the region not reaching the neck seal line 1e.

That is, in the conventional example, the alternating electric field of the deflection yoke transmitted through the funnel and radiated from the front surface of the face panel is reduced in a predetermined area from the cone portion into which the deflection yoke of the funnel is fitted to the neck portion. For this purpose, the conductive film 7 for electric field shield is provided, and the equipotential surface of OV, that is, the electric field shield surface is formed on the inner peripheral surface of the front opening of the deflection yoke, so that it passes through the funnel and the face panel. The alternating electric field radiated to the front surface can be reduced.

Hereinafter, a conventional example will be specifically described with reference to FIG. FIG. 4 shows a configuration diagram of a cathode ray tube according to an example in which a conductive film for electric field shielding is provided. The electric field shield conductive film 7 is formed by applying graphite from the cone portion 1b to the neck portion 1a so as to electrically contact the conductive film 6 in order to form an electric field shield surface. The electric field shielding conductive film 7 is formed so as to cover the front opening of the deflection yoke 9. Along with the formation of the conductive film 7, a funnel-shaped insulating sheet 8 is provided to electrically insulate the conductive film 7 from the coil portion of the deflection yoke 9. The insulating sheet 8 has a funnel shape as shown in FIG. 5, and is attached from the cone portion 1b of the funnel to the neck portion 1a. Then, as shown in FIG. 6, the deflection yoke 9 is attached from above the insulating sheet 8.

By grounding the conductive film 7 of the cathode ray tube configured as described above, the conductive film 7 becomes an equipotential surface of OV, and a surface having an electric field shield effect is formed in the front surface region of the deflection yoke 9 for deflection. The alternating electric field that penetrates the funnel 1 from the yoke 9 and reaches the face panel is reduced. Since the insulating sheet 8 is interposed between the coil portion of the deflection yoke 9 and the conductive film 7, the coil portion of the deflection yoke 9 and the conductive film 7 are electrically insulated. No problems such as discharge will occur. Of course, the conventional capacitance-adding conductive film 6 is also grounded. As described above, according to the conventional example, the conductive film 7 for electric field shield is formed from the neck portion 1a of the funnel 1 of the glass bulb 20 to the cone portion 1b, and is electrically connected to the conductive film 6 for adding capacitance. By disposing the deflection yoke 9 on the conductive film 7 via the insulating sheet 8 and grounding the conductive film 7, the alternating electric field transmitted through the face panel is reduced by about 40% as compared with the conventional case. By the way, there is also a cathode ray tube which does not take measures against the leaking alternating electric field. Since this cathode ray tube does not have the electric field shielding conductive film 7 on its outer surface, the deflection yoke 79 can be directly attached to the tube wall without the interposition of the insulating sheet 8.

[0008]

[Problems to be solved by the device]

 As described above, the conventional cathode ray tube has two types of cathode ray tube exterior specifications. One has the conductive film 7 in the cone portion facing the front opening of the deflection yoke 9 and the other does not, as shown in FIG. There was a problem that two kinds of things had to be prepared.

The present invention has been made in order to solve the above problems, and can reduce the alternating electric field generated from the deflection yoke and leaking from the front of the cathode ray tube without increasing the types of the cathode ray tube. The purpose is to make it possible to take countermeasures to the cathode ray tube at any time.

[0010]

[Means for Solving the Problems]

 A cathode ray tube according to the present invention has a conductive film for electric field shield on an inner side surface between a deflection yoke and a tube wall in a predetermined region from a cone portion of a funnel in which a deflection yoke is fitted to a neck portion. A funnel-shaped insulating sheet is interposed, and the conductive film provided on the inner side surface of the funnel-shaped insulating sheet forms an electric field shield surface.

[0011]

[Action]

 In this invention, the cathode ray tube itself is exactly the same as the conventional product in which no measures are taken against the leakage alternating electric field from the front surface of the face panel, but it is used on the front opening side of the deflection yoke. By grounding the conductive film applied to the inner surface of the funnel-shaped insulating sheet provided to the ground potential, a conductive film for electric field shielding is provided on the outer surface of the cone part of the cathode ray tube to drop it to the ground potential and the electric field shield surface. The same shielding effect as that of forming the is obtained.

In the present invention, the electric field shield is formed by using the conductive film provided on the inner surface of the funnel-shaped insulating sheet provided on the front opening side of the deflection yoke as, for example, the ground potential. Of the electric field shielding conductive film provided on the inner side surface of the funnel-shaped insulating sheet can be set to the ground potential. I can.

[0013]

【Example】

 Example 1. An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a funnel-shaped insulating sheet 10 of the present invention having a conductive film 11 for electric field shielding on its inner surface. FIG. 2 shows a diagram in which the funnel-shaped insulating sheet 10 having the conductive film 11 for electric field shielding on the inner surface is attached to the cone portion 1b of the funnel. The cathode ray tube itself is no different from the conventional one (cathode ray tube that does not take measures against leakage alternating voltage), and only the conductive film 6 for adding capacitance is coated with graphite on the outer surface of the funnel body. It is formed by. Further, as shown in FIGS. 2 and 3, the front end of the electric field shielding conductive film 11 provided on the inner side surface of the funnel-shaped insulating sheet 10 has an electrostatic capacitance adding conductive film 6 provided on the outer side surface of the funnel body. It comes in contact with and overlaps with. As shown in FIG. 3, the deflection yoke 9 is attached from above the funnel-shaped insulating sheet 10.

In the present invention, the cathode ray tube itself may be the same as the conventional product in which no measures are taken against the conventional alternating electric field from the front face panel. Therefore, it is possible to take measures against the alternating electric field at any time. In that case, the funnel-shaped insulating sheet 10 having the conductive film 11 for electric field shielding on the inner surface is attached to the cone portion 1b of the funnel, and the front end of the conductive film for electric field shielding is attached to the funnel body 1c to add an electrostatic capacity. Is overlaid on the conductive film 6. Here, if the conductive film 6 for capacitance addition provided in the funnel body is grounded to the ground potential as in the conventional case, the conductive film 11 for electric field shield on the inner side surface of the funnel-shaped insulating sheet 10 also becomes the ground potential and shields the alternating electric field. It will be possible.

[0015]

[Effect of the device]

 As described above, according to the present invention, as a measure against an alternating electric field, a predetermined area from the cone portion of the funnel in which the deflection yoke is fitted to the neck portion is provided without any treatment on the outer surface of the cathode ray tube itself. It is only necessary to provide a funnel-shaped insulating sheet with a conductive film formed on the inner surface, and the funnel-shaped insulation sheet of the present invention can be used without distinguishing the type of exterior specifications of the cathode ray tube from those for alternating electric field countermeasures and those not. Only by preparing an insulating sheet (having a conductive film on the inner surface), it is possible to add measures against alternating electric fields at any time.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of a funnel-shaped insulating sheet which is a main part of the present invention.

FIG. 2 is a sectional view of a main part of a cathode ray tube according to an embodiment of the present invention.

FIG. 3 is an overall side view of a cathode ray tube according to an embodiment of the present invention.

FIG. 4 is an overall side view of a conventional cathode ray tube.

FIG. 5 is a perspective view showing a conventional funnel-shaped insulating sheet.

FIG. 6 is a cross-sectional view of a main part of a conventional cathode ray tube.

FIG. 7 is a perspective view of a deflection yoke.

[Explanation of symbols]

 10 funnel-shaped insulating sheet 11 conductive film for electric field shield 1 funnel 1a neck part 1b cone part 1c funnel body part 6 conductive film for adding capacitance 1d anode button 1e neck seal line 2 face panel 3 electron gun 4 explosion-proof band 4a mounting Ear 5 Silicon resin film 9 Deflection yoke 20 Glass bulb

Claims (1)

[Scope of utility model registration request] 1. A neck portion in which an electron gun is sealed, a funnel main body portion having a conductive film for adding capacitance on a part of its outer surface, and a cone connecting the neck portion and the funnel main body portion. And a face panel having a phosphor film on the inner surface and arranged at one end of the funnel body opposite to the side connected to the cone portion, and the funnel to the neck from the cone portion to the neck. In a cathode ray tube having a deflection yoke which is fitted over a portion to deflect an electron beam emitted from the electron gun, an inner surface is formed in a predetermined region from a cone portion where the deflection yoke of the funnel is fitted to a neck portion. A cathode ray tube, characterized in that a funnel-shaped insulating sheet having a conductive film for electric field shielding is provided on the.