JPS5847641Y2 - cathode ray tube - Google Patents

Description

[Detailed description of the invention] This invention suppresses the large current flowing during high voltage discharge by increasing the electrical resistance of the internal conductive film provided on the inner surface of the vacuum envelope, and is used in cathode ray tube control circuits, etc. The present invention relates to a cathode ray tube that has been improved so as to prevent damage to semiconductor components and to prevent short circuits caused by getters.

FIG. 1 is a circuit diagram illustrating a conventional cathode ray tube used in a television receiver.

In FIG. 1, an inner conductive film 3 is coated on the inner surface of a funnel portion 2 constituting a vacuum envelope of a cathode ray tube 1, and an outer conductive film 4 is coated on the outer surface.

The neck portion 5 of the cathode ray tube 1 has an anode portion 6 constituting an electron gun.
And the electrode of the cathode part 7 is inserted.

Note that the cathode section 7 consists of a cathode 71 and intermediate electrodes 72 and 73.

The cathode section 7 is connected through a stem section 8 and a socket 9 to a chassis circuit section 10 of the television receiver.

A high voltage is applied to the anode button 11 embedded in the center of the funnel part 2 by a flyback transformer of the television receiver, and this voltage is applied to the spacer 13 attached to the anode part 6 via the internal conductive film 3. From anode part 6
added to.

The deflection yoke 14 attached to the outer walls of the funnel part 2 and neck part 5 of the cathode ray tube 1 is connected to the chassis circuit part 10 by a lead wire 15, and the external conductive film 4 and the ground terminal of the socket 9 are connected by a lead wire 16. tied together.

Further, a phosphor 18 is coated on the panel portion 17 of the cathode ray tube 1, and a mask 19 and a holder 20 are applied at a slight interval thereto.
Supported by

The anode part 6 is separated from the anode 61 and the cup 62 for attaching the spacer 13 as shown in FIG. 22 is attached.

In such a cathode ray tube circuit, when a high voltage discharge occurs between the anode section 6 and the cathode section 7 of the cathode ray tube 1, most of the charge contributing to this high current discharge is transferred to the inside of the cathode ray tube 1. Conductive film 3
and the outer conductive film 4 or the inner conductive film 3 and the deflection yoke 1
Since this charge is stored in the capacitance existing between the internal conductive film 3 and the anode section 6. It flows through the cathode portion 7 to the external conductive film 4 .

At this time, the capacitance is, for example, as high as 2000 PF, and the electrical energy stored therein is quite large, and since the resistance of the discharge circuit is small, the current that flows reaches 100 A.

Therefore, an abnormal voltage is applied to the semiconductor elements used in the chassis circuit section 10 due to electromagnetic induction or electrostatic induction caused by this discharge flow, and some of them may be destroyed.

Alternatively, if the cathode ray tube is used in a computer, it may cause malfunction.

Therefore, in order to eliminate such accidents, in the preliminary stages leading to the present invention, the number of internal conductive films 3 through which the discharge current flows is set to 1 per 1 cm2! 2 to 1000 K,! We devised a method to limit the discharge current during high-voltage discharge by forming a high-resistance conductive film with an electrical resistance value of Q.

However, if only this method is used, the internal conductive film 3 of the neck portion 5 will be short-circuited by the antenna getter 20 provided in a normal cathode ray tube, so that the internal conductive film 3 and the deflection yoke 14 will accumulate. With respect to the obtained charge or the charge stored in the vicinity of the getter 22, it is not possible to limit the discharge current during discharge.

Therefore, as a second step in arriving at the present invention, as shown in FIG. 3, an insulating support rod 24 is inserted between the anode section 6 and the getter 22 to prevent the internal conductive film 3 of the neck section 5 from short-circuiting. I came up with this, but not only getter 22
Because the getter flash is performed by high-frequency heating,
The getter film 25 is formed as shown in the figure, so if only the insulating support rod 24 is provided, the anode portion 6 and the getter 22 may be short-circuited.

Therefore, as a third step, a conventional getter shield 2 is used to prevent this getter film 25 from scattering to the neck part 5.
6. I installed the getter sight shield 27 by welding it.

However, an experiment revealed that the getter film 25 scattered on the neck portion 5 could not be effectively shielded yet.

Furthermore, with this alone, when the internal conductive film 3 having a high resistance comes into direct contact with the spacer 13, the contact resistance becomes large, so there is still a risk that Joule heat will be generated during the discharge inside the tube and glass cracks will occur.

In the final step of the present invention, in order to eliminate all of these drawbacks, in addition to the previous stage, an internal conductive film with a high resistance value is added to the part that does not contact the electron gun spacer, and a low-resistance film is installed to the part that makes contact with the electron gun spacer. By applying an internal conductive film with a resistance value, using a long spacer in the circumferential direction, and welding the spacer to the cathode side end of the spacer mounting cup, large currents can be prevented and short circuits can also be prevented. The purpose is to prevent the occurrence of cracks.

This will be explained below with reference to the drawings.

FIG. 4 shows an embodiment of the present invention in which a circumferentially long spacer 113 is attached to the cathode side end of a spacer attachment cup 62, and a low-resistance internal conductive film 31 is applied to the inner wall of the neck portion facing the space. It is.

The getter film 25 is a getter shield 26. Although the getter sight shield 27 prevents scattering toward the spacer mounting cup 62,
During the getter flash, a region with a high concentration of getter particles is created, and the getter particles collide with each other to form a getter film 25 close to the upper end of the spacer attachment cup 62 from which the getter particles collide in all directions.

However, the getter film 25 cannot be formed because there is a gap between the spacer attachment cup 62 and the high-resistance internal conductive coating 3 applied to the inner wall of the neck portion 3 and because the getter film 25 is hidden from the getter 22.

Therefore, the spacer 113 and the getter film 25 are long in the circumferential direction.
A high-resistance internal conductive film 3 without a getter film 25 is formed between the ends of the tube and the inner conductive film 3, thereby suppressing the discharge current inside the tube.

Since the discharge flow concentrates at the contact point with the internal conductive coating of the spacer 113, Joule heat is generated there, and there is a risk that the glass of the neck portion 5 will crack.

For this reason, a low-resistance internal conductive film 31 having a width of 10 mm or less and having a resistance value of 10J7 to IKQ per cm'' is applied to the portion in contact with the spacer 113.

During application of this film 31, it is better to have a narrow width, but from the standpoint of dimensional accuracy, a width of approximately 10 cm is required.

This coating 31 prevents the generation of Joule heat and, in turn, prevents the generation of cracks.

Furthermore, since the insulating support rod 24 is provided between the getter 22 and the anode section, it is possible to prevent the internal conductive film of the neck section 5 from shorting.

FIG. 5 is an enlarged view of the vicinity of the anode portion of FIG. 4, showing the relationship between the horizontal spacer 113 and the neck portion 5. As shown in FIG.

Although the case where the anode 61 and the spacer attachment cup 62 are separate has been described here, it goes without saying that the same applies to the case where the spacer 113 is attached to the anode 61.

As described above, the cathode ray tube of the present invention includes an electron gun consisting of a cathode section 7 and an anode section 6, a getter 22 fixed to the anode section 6, and a space between the getter 22 and the anode section 6. an insulating support rod 24 provided, a circumferentially long spacer 113 provided on the cathode portion 7 side of the anode portion 6, and a portion 31 provided on the inner surface of the cathode ray tube 1 that corresponds to at least the spacer 113. Electrical resistance is 1 per cm2
Off or 1 has a resistance value of Ω, and other parts 3
at least a portion of 1KQ to 100O/cm2
Since it is provided with an internal conductive coating having resistance values of K and Q, it is possible to suppress the discharge current of the cathode ray tube, prevent short circuits due to getters, and prevent cracks from occurring.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view showing the case where the layered parts of a conventional cathode ray tube are installed, Fig. 2a is an enlarged configuration diagram of the anode section of Fig. 1, and Fig. 2 is A-A in Fig. 2a. A cross-sectional view, FIG. 3 is a diagram showing the position of the getter film of the conventional structure with an insulating support rod, which is a part of the present invention, and FIG. 4 is a configuration diagram showing an embodiment of the present invention. FIG. 5 is an enlarged view of the vicinity of the anode section. In the figure, 1 is a cathode ray tube, 3 is a high-resistance internal conductive coating, 5 is a neck part, 6 is an anode part of an electron gun, 7 is a cathode part of an electron gun,
22 is a getter, 24 is an insulating support rod, 31 is a low resistance internal conductive coating, 62 is a spacer mounting cup, and 113 is a spacer long in the circumferential direction. Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (1)

[Scope of utility model registration request] A vacuum envelope, an electron gun in the vacuum envelope consisting of a cathode part and an anode part, a getter fixed to the anode part, and an insulating support rod provided between the getter and the anode part. a circumferentially long spacer provided on the cathode side of the anode part; and a spacer provided on the inner surface of the vacuum envelope, the electrical resistance of which is at least 1 cm in the portion corresponding to the spacer.
It has a resistance value of 2 Ω to 1 Ω, and at least a part of the other part has a resistance value of 1 KΩ to 10 Ω per 1 cm2.
1. A cathode ray tube, comprising: an internal conductive coating having a resistance value of 00 and Ω.