KR0140070Y1 - Structure of electron gun used in a crt - Google Patents

Abstract

The present invention relates to the structure of the electron gun for cathode ray tube, in particular to reduce the stress formed between the insulating support, the control electrode and the acceleration electrode, and to prevent the expansion of the electrode due to residual stress during operation of the cathode ray tube quality and reliability Since the overall characteristics of the cathode ray tube can be configured as originally designed, it is possible to improve the resolution characteristics of the cathode ray tube because it brings good results throughout the whole, and is thus fused with the insulating support of the control electrode and the acceleration electrode. Single or multiple apertures are formed over the boundary.

Description

Electron gun structure for cathode ray tube

1 is a cross-sectional view of a typical cathode ray tube.

2 is an electrode support structure of an electron gun for a cathode ray tube.

3 is a structural diagram of a conventional electrode.

(A), (b), and (c) of FIG. 4 are diagrams of electrode depressions of a conventional electrode.

(A) of FIG. 5 is a change diagram of a conventional cathode current.

(b) is a state diagram of the conventional current change.

6 is a structural diagram of an electrode according to the present invention.

Figure 7 (a) (b) (c) is another embodiment of the present invention through shape.

Figure 8 (a) is a change in the cathode current according to the present invention.

(b) is a synthetic state diagram of the current change according to the present invention.

* Explanation of symbols for main parts of the drawings

100 electrode 101 side beam ball

102: center beam ball 103: through hole

104: insulation support

The present invention relates to an electron gun structure for a cathode ray tube, and in particular, to minimize stress between the cathode, the control electrode, and the accelerating electrode due to heat transfer due to the heat generation of the heater, to absorb the stress with an insulating support for fixing the electrode. It is a modification of the structure.

Looking at the configuration of a typical cathode ray tube, as shown in FIG. 1, the panel 13 mounted on the front surface of the CRT and the phosphors of red (R), green (G), and blue (B) are formed on the inner surface of the panel (13). The coated fluorescent surface 17, the shadow mask 16 having a color selection function while passing through the electron beam 15 incident on the fluorescent surface 17, and the back of the panel 13 is coupled to vacuum the inside of the cathode ray tube A funnel 14 to be kept in a state, a deflection yoke 12 surrounding the outer side of the funnel 14 to deflect the electron beam 15, and a tubular neck portion retracted to the rear of the funnel 14 ( 14 '), the exterior is constructed.

The electron gun mounted in the neck portion 14 'is provided with a negative electrode 3 having a heater 2 therein, which receives power from the stem pin 1 and generates heat, and in front of the negative electrode 3 electrons are formed. The controlling control electrode 4 and the accelerating acceleration electrode 5 are positioned, and the first, second, third and fourth acceleration / focusing electrodes 6, 7, 8, and 9 forming the prefocus lens and the main lens are positioned. Are arranged sequentially. In addition, a shield cup 10 in which a bulb space contact 11 for welding an electron gun is welded to the neck portion 14 ′ of the cathode ray tube is disposed in front of the fourth acceleration / focus electrode 9.

In the conventional cathode ray tube electron gun configured as described above, when the heater 2 receives the power (6.3V) from the stem pin 1 and generates heat, the temperature of the cathode becomes about 800 ° C., and heat electrons from the cathode 3 are heated by this heat. The emitted and emitted electrons are controlled and accelerated while passing through the control electrode 4 and the acceleration electrode 5, and then are prefocused lenses formed by the first, second, and third acceleration / concentration electrodes 6, 7, and 8. The radiation angle of the electron beam 15 is reduced and focused and accelerated by the main lens formed by the third and fourth acceleration / concentration electrodes 8 and 9 to pass through the shadow mask 16 installed in front of the fluorescent surface 17. It collides with the fluorescent surface 17 to emit light.

2 is a bead mount structure which is a basic skeleton of an electron gun embedded in a color cathode ray tube.

Here, the cathode support 27 is fused and fixed with a plurality of electrodes at regular intervals by the plurality of insulating supports 26. In order to configure the cathode support, the electrodes arranged at regular intervals are heated by a predetermined temperature before insulation. After the agent is made in a semi-melt state, it is fused and fixed to the recess 21 which is an outer portion of each electrode. Here, after the electrodes are fusion-fixed to the insulating support 26, the completed electron gun is sealed in a cathode ray tube, and then subjected to an exhaust process of releasing air in the cathode ray tube to vacuum the cathode ray tube. Since the degree of vacuum greatly affects the electron emission characteristics of the cathode ray tube, the degree of vacuum after exhaust should be 5 × 10 ^-6 Torr.

The cathode ray tube subjected to the exhaust process is subjected to getter flashing to remove residual gas which is not completely removed during exhaust. Since the material of the getter is barium, the barium film is formed on the inner wall of the cathode ray tube and remains. Absorb gas. However, the vacuum degree during getter pressing increases ^to 5 × 10 ^{-4 to -5} Torr as the gas of the getter itself is released.

Cathode ray tube, which has been obtained by pressing, is subjected to an aging process to emit electrons from the electron gun. AC 9V is applied to the heater 2, DC 8V is applied to the control electrode 4, and DC 260V is applied to the acceleration electrode 5. This is done by dividing into current activation for stabilization.

Through this process, the carbonate attached to the upper portion of the cathode 3 is completely decomposed, and the active electron emission is possible. At this time, heat is generated from the cathode 3 and each of the electrodes receives heat and expands. Among the electrodes, the control electrode 4 located relatively close to the cathode 3 receives the most heat and then accelerates. Heat is received in the order of the electrode 5, and since the control electrode 4 and the acceleration electrode 5 of the above electrodes are formed in a single plate shape, they are more affected by heat, and in particular with the insulator 26. The stress of the plate electrode, which is generated during fusion and remains on the electrode, helps to expand due to heat and thus has a greater adverse effect on the screen characteristics of the cathode ray tube.

Therefore, when the shape of the depression 21 of the conventional electrode, as shown in the various shapes shown in FIG. 4, the depression 21 with the insulator support 26 is formed in the shape of a simple cutout 22 to operate the cathode ray tube. The expansion caused by the heat generated during the transfer is transferred to the control electrode 4 and the acceleration electrode 5 as it is, and the stress between the insulating support 26 is the electron beam through hole (19, 20) of the control electrode 4 and the acceleration electrode (5). There is a problem in that the phenomena occur in the direction of the) and bad results on the electron beam focusing characteristics of the cathode ray tube.

As a result of this phenomenon, among the electrodes of the conventional electron gun, in particular, the control electrode 4 and the acceleration electrode 5 retain the stresses generated when the insulation support 25 is bonded to each other, and the stress is applied to the heat conducted by the heater 2. As a result, the degree of expansion of the control electrode 4 and the acceleration electrode 5 which expands in the opposite direction to the cathode is further enhanced. That is, the control electrode 4 and the acceleration electrode 5, which are expanded by heat, move away from the cathode 2, and the cathode support 27 expands in the opposite direction so that the cathode current falls as shown in FIG. . Combining this change of current, it appears as (b) of Fig. 5, which is called the over shoot characteristic curve, and the overshoot characteristic amount of a general electron gun It is generally shown to be about 90 ~ 140%, the development of a high-resolution electron gun, the smaller the through hole of the control electrode 4 and the acceleration electrode 5, the more sensitive the effect of thermal expansion by the heater (2).

In view of the above, the present invention has a through hole at the fusion boundary of the control electrode and the acceleration electrode with the insulating support to reduce the stress formed between the insulating support, the control electrode and the acceleration electrode, and to prevent expansion due to residual stress. The purpose is to.

The invention is described in detail below with reference to FIGS. 6 to 8.

First, as shown in FIG. 6, the through hole 103 is formed on the fusion boundary between the side beam hole 101 through which the electron beam passes, the control electrode on which the center beam hole 102 is formed, and the insulating support 104 of the acceleration electrode 100. ) Was formed.

In the drawing, reference numeral F denotes a depression recessed in the insulating support 104.

That is, during operation of the cathode ray tube, conduction heat conducted from the cathode causes the control electrode 3 or the accelerating electrode 4 to expand in the opposite direction to the cathode, and receives the heat from the control electrode 3 which is in a soft state. The stress with the insulating support 104 on the acceleration electrode 4 acts to increase the expansion of the electrode even more strongly, but the control electrode or the acceleration electrode 100 according to the present invention has a stress with the insulating support at the interface of the insulating support 104. It is absorbed into the formed through hole 103 and can eventually eliminate the adverse effects on the electron beam through holes 101 and 102 as well as the effect of expansion.

In fact, the tripolar thermal expansion of the conventional electron gun shows that when the voltage is applied to the heater 2, the expansion amount of the cathode 3 is 62 µm, the control electrode 4 is 12 µm, and the acceleration electrode 5 The expansion amount is about 23 μm, and the expansion amount of the control electrode 4 and the accelerating electrode 5 is mostly caused by the stress between the insulating support 26.

In this case, as shown in FIG. 8, the change of the cathode current caused by the control electrode or the acceleration electrode becomes small, resulting in an overshoot characteristic amount. The effect is 35%, so the settling time will be shortened, which will have a significant effect on improving the reliability.

In another embodiment, as shown in (a), (b), and (c) of FIG. 7, a plurality of through holes may be formed, or through holes may be formed in various shapes to remove stress. do.

The present invention as described above, while reducing the stress formed between the insulating support 104, the control electrode, the acceleration electrode, while preventing the expansion of the electrode by the residual stress during operation of the cathode ray tube quality of the cathode ray tube And since it brings about good results in overall reliability, all the characteristics of the cathode ray tube can be configured and manufactured as originally designed, thus devising an improvement in the resolution characteristics of the cathode ray tube.

Claims (1)

A tripolar portion consisting of a cathode for generating an electron beam, a plate-shaped control electrode and an acceleration electrode, and a first acceleration / focus electrode and a second acceleration / focus electrode for forming a main lens so as to accelerate and focus the electron beam to form a fluorescent surface. The electron gun structure of claim 2, wherein the through-holes are formed in the fusion boundary with the insulating support so as to absorb the stress of the control electrode and the acceleration electrode.