JPH081793B2 - Cathode ray tube - Google Patents

Description

The present invention relates to a soft flash type cathode ray tube.

[Conventional technology]

FIG. 7 is a partially cutaway side view of a conventional soft flash type cathode ray tube, and FIG. 8 is a cross-sectional view of an essential part thereof. In the figure, an electron gun 3 is enclosed in a neck portion 2 of a cathode ray tube envelope 1. A valve spacer 5 and a getter 6 are attached to the anode 4 of the electron gun 3. The getter 6 has a getter spring 7 and a getter ring 8 with an insulator 9 inserted in the middle. The getter ring 8 is welded to one end of the getter spring 7, and the other end is welded to the anode 4. The insulator 9 is for preventing the current at the time of discharge in the tube from flowing through the getter spring 7. Reference numeral 10 denotes a high resistance internal conductive film formed on the inner wall of the funnel 1a of the cathode ray tube envelope 1.
The getter spring 7 is electrically connected to the getter spring 7 via a connector 11. On the other hand, the spacer 5 is in contact with the low resistance internal conductive film 12 on the inner wall of the neck portion 2. The high resistance internal conductive film 10 generally has a specific resistance of 1 Ω-cm or more, and contains a large amount of metal oxide such as titanium oxide as compared with the low resistance internal conductive film 12 having a specific resistance of 1 Ω-cm or less.

[Problems to be solved by the invention]

During the manufacturing process of such a cathode ray tube, the induction current is passed from the outside of the cathode ray tube by the high frequency heating device coil 13,
The getter ring 8 is heated to perform getter flushing. At this time, the getter ring 8 is heated to 800 ° C. to 1000 ° C. or higher, so that the high resistance internal conductive film in contact with the connector 11
The temperature of 10 rises from 400 ° C to 800 ° C. Since the time required for this getter flashing is about 30 seconds to 1 minute, the high resistance internal conductive film 10 is subject to a sudden temperature shock, and a phenomenon such as cracking occurs at the contact portion with the connector 11. , Its resistance may exceed 50 MΩ. Therefore, since the insulator 9 is interposed between the getter ring 8 and the anode 4, the getter ring 8 is electrically floated from the high resistance internal conductive film 10. When the cathode ray tube is operated in such a state, the electrons from the electron gun 3 collide with the fluorescent surface (not shown) of the cathode ray tube, and a part of the scattered electrons are captured by the getter ring 8. , Gradually become negative (voltage). Getter ring 8 by this charge
The electron beam that has passed the vicinity is bent and deviates from the normal orbit, and as a result, the image displayed on the screen of the cathode ray tube is distorted.

It is not clearly known why the portion of the high-resistance internal conductive film 10 in contact with the connector 11 has a high resistance of 50 MΩ or more. Since graphite, water glass, and metal oxides forming the conductive film 10 have different thermal expansion coefficients, a rapid temperature change at the time of getter flush causes cracks inside the conductive film 10. It is presumed that this may cause the loss of conductivity.

The present invention has been made to solve the above problems, and does not cause any inconvenient symptom even if the resistance of the high-resistance internal conductive film in contact with the getter connector at the time of getter flashing is increased. The purpose is to obtain a cathode ray tube.

[Means for solving problems]

The cathode ray tube according to the present invention includes a cathode ray tube envelope having a neck portion and a funnel portion, an electron gun enclosed in the neck portion, an internal conductive film formed on the inner wall of the funnel portion, and one end of which is the above-mentioned. A getter spring attached to the electron gun and extending into the funnel portion without contacting the internal conductive film, and a getter ring supported by the other end of the getter spring and having a recess on the surface facing the internal conductive film. A crossbar fixed to the getter ring across the recess, a base having a guide groove into which the crossbar is fitted and housed in the recess of the getter ring, and protruding toward the internal conductive film side. A heat-resistant insulating connector comprising a convex portion and a holder fixed to the getter ring for holding the base portion of the insulating connector in the concave portion. Example, in which a convex portion of the insulating connector is brought into contact with the inner conductive film electrically insulating the said getter ring and the inner conductive film.

[Action]

According to the present invention, the insulating connector is attached to the getter ring, further held by the holder, and securely fixed in a state in which the crossbar attached across the recess on the bottom surface of the getter ring is fitted into the guide groove of the insulating connector. To be done.

Also, since a heat-resistant insulator is used as the insulating connector, the resistance of the high-resistance internal conductive film does not increase at the contact of this connector, or even if it increases, the getter ring is always in electrical contact with the anode. In addition, the electrostatic charge due to the scattered electron beam does not occur, and the image distortion does not occur.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view of the main part of the cathode ray tube, in which 14 is a heat-resistant insulating connector provided in the getter ring 8 and has a length of 1 cm.
It maintains an electrical insulation state with the high resistance internal conductive film 10 having a resistance value between two distant points of 100Ω to 1000KΩ.
The use of this connector 14 eliminates the need for the central insulator 9 of the getter spring 7 of the conventional example. The other parts are the same as in the case of the conventional example shown in FIG.

2 and 3 show the mounting structure of the insulating connector 14 to the getter ring 8, and FIGS. 4 to 6 show exploded perspective views of the getter ring 8 and the insulating connector 14.
That is, while the insulating connector 14 is housed in the recess 8c in the center of the getter ring 8, the guide groove 14a is fitted and fixed in the crossbar 8a welded and fixed to the center of the getter ring 8, and then the contact 14b of the insulating connector 14 is held in the holder 15 windows 1
5b is inserted, and then the holder 15 made of a non-magnetic alloy is welded and fixed to the getter ring 8 for assembly.

In the cathode ray tube of the present invention configured as described above, even if a high frequency current is applied to the high frequency heating device coil 13 to heat the getter ring 8 to 800 ° C. to 1000 ° C., the insulating connector 14 has a low thermal conductivity, so that It is difficult to apply thermal shock to the resistance internal conductive film 10, and the resistance value does not increase at the contact point 14b. Even if the resistance value increases, the getter ring 8 is always electrically connected to the anode 4 and the getter spring 7, so that the scattered electron beam or the like does not cause the charge and the display on the screen of the cathode ray tube. It does not distort the rendered image.

Further, generally, the total weight of the getter ring 8 and its attached portion is preferably lighter because the getter spring 7 is pressed against the cathode ray tube envelope by using the spring force of the getter spring 7. Therefore, the insulated connector 14 is The smaller the better. With the above structure, the small insulated connector 14 can be stably fixed to the getter ring 8. Further, in order to prevent discharge from occurring between the getter ring 8 and the surface of the high resistance internal conductive film 10, the holder 15 should be separated from the high resistance internal conductive film 10 as much as possible, but the above structure is excellent in this respect. It has excellent characteristics.

Conventionally, when the getter ring 8 is getter flushed, the ring 8 becomes hot and the cathode ray tube envelope may be damaged due to its heat radiation. As a countermeasure against this, for example, US Pat. A returnable ceramic base as described in Japanese Patent No. 3381805 and Japanese Utility Model Publication No. 58-13575 is arranged between the getter ring and the envelope. This ceramic base is placed at a position facing the channel 8b (groove containing the getter barium particles) of the getter ring 8 to block the high temperature from the channel 8b. On the other hand, in the present invention, since the insulating connector 14 is arranged in the recess 8c in the center portion of the getter ring 8 (it is difficult for the temperature to be high during getter flushing), the purpose and the configuration are different.

As described above, according to the present invention, the insulating connector is attached to the getter ring in a state where the crossbar attached across the recess on the bottom surface of the getter ring is fitted into the guide groove of the insulating connector. Further, since it is held by the holder, the insulating connector does not move in the radial direction or the height direction of the getter ring, and is securely fixed. Further, since the getter ring and the insulating connector are securely fixed, even if the getter ring is heated to a high temperature during getter flashing, the insulating connector is not loosened and the insulating state between the internal conductive film and the getter ring can be maintained.

In addition, by electrically insulating the getter ring and the internal conductive film with a heat-resistant insulating connector, it is possible to block the current flowing through the getter spring during internal discharge of the cathode ray tube, and the getter ring is always electrically connected to the anode. Since they are electrically connected to each other, it is possible to prevent the getter ring from being charged by the scattered electron beam and the like, thereby providing a cathode ray tube in which image distortion does not occur.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a main portion around a getter of a cathode ray tube according to an embodiment of the present invention, FIGS. 2 and 3 are bottom views of a getter ring and an insulating connector, and a cross-sectional view taken along line III-III of FIG.
4 to 6 are exploded perspective views of the getter ring and the insulating connector, FIG. 7 is a broken cross-sectional view of a conventional cathode ray tube, and FIG. 8 is a cross-sectional view around the getter. 1a: Funnel part, 4 ... Anode, 7 ... Getter spring, 8 ... Getter ring, 8a ... Crossbar, 8c
...... Dent, 10 ...... High resistance internal conductive film, 14 ...... Insulation connector, 14a ...... Guide groove, 14b ...... Contact, 15 ...... Holder. The same reference numerals in the drawings indicate the same or corresponding parts.

Claims (1)

[Claims] 1. A cathode ray tube envelope having a neck portion and a funnel portion, an electron gun enclosed in the neck portion, an internal conductive film formed on the inner wall of the funnel portion, and one end of the electron gun. A getter spring that is attached and extends into the funnel portion without contacting the internal conductive film; a getter ring that is supported by the other end of the getter spring and that has a recess on the surface facing the internal conductive film; A crossbar fixed to the getter ring across the recess, a base having a guide groove into which the crossbar is fitted and housed in the recess of the getter ring, and a protrusion protruding toward the internal conductive film. And a holder fixed to the getter ring to hold the base of the insulated connector in the recess. Cathode ray tube, characterized in that the convex portion of the insulating connector is brought into contact with the inner conductive film is electrically insulating and the getter ring and the inner conductive film.