KR19980017711A - Cathode structure of electron gun for cathode ray tube - Google Patents

Abstract

The present invention is to improve the cathode structure of the cathode ray tube gun tank to improve the thermal efficiency of the cathode of the cathode ray tube electron gun and to minimize the overshoot due to thermal expansion to implement a stable cathode electron emission.

To this end, the present invention is a cone-shaped metal connector (3) interconnecting the sleeve (2) and the support (1) at the top of the support (1) and the bottom of the sleeve (2) inserted into the center of the support (1) ) Cathode structure of electron gun for cathode ray tube with both ends fixed respectively.

Description

Cathode structure of electron gun for cathode ray tube

The present invention relates to a cathode structure of an electron gun for a cathode ray tube, and more particularly, to an improvement of a cathode structure of an electron gun for a cathode ray tube to realize electron emission of a stable cathode.

As shown in FIGS. 1A and 1B, a cathode structure of a conventional cathode ray tube electron gun includes a heat dissipating cathode structure divided into a three-piece type and a ribbon type, and in addition, there is a spider type (not shown).

On the other hand, Figure 1a is the most commonly used three-piece type heat dissipation cathode structure, the cap 7 and the heat of the heater 8 is applied to the cap 7, the carbonate (6) is applied to the front end surface toward the cap (7) And a holder 9 for supporting the sleeve 2.

FIG. 1B is a ribbon type heat dissipating cathode structure, in which a carbonate 6 is applied to a tip end surface thereof, and the cap 7 is assembled to a heat cap 7 of the heater 8. Ribbon (10) (Ribbon) that connects the sleeve (2), which serves as a passage for transmitting to the side, the sleeve (2), and the sleeve (2) and the support (Support) (1) It is composed of

In addition, the spider type negative electrode structure cuts the outer wall of the support similarly to the ribbon 10 of FIG.

In the conventional negative electrode structure configured as described above, when power is applied to the heater 8, the heat of the heater 8 is cut by the cap 7 so that the carbonate leaf 6 is heated so that electrons are emitted from the carbonate 6. The emitted electrons are accelerated and connected while sequentially passing through the electron beam passing holes of the plurality of grid electrodes (not shown) to reach the phosphor coated on the cathode ray tube, thereby causing an image to appear on the screen.

On the other hand, the vacuum through the manufacture of the cathode structure, the cap 7, the exhaust step and the getter pressing (Getter Flashing) process in order to be electron emission from the carbonates (6) is applied on the top face of the cap (7) 5 × 10 ^{- After 6} Torr, the aging should be carried out so that the vacuum pressure is 5 × 10 ^-7 Torr.

The aging process carried out in this case includes various processes and can be divided into unit processes such as knocking, thermal activation, and current activation.

First, knocking is a process of burning and removing foreign substances attached to the electrode by applying a high pressure to the electrode of the electron gun.

In the thermal activation process, the carbonate 6 is decomposed while gradually increasing the voltage applied to the heater 8 from a low voltage of 5V to a high voltage of about 11V, and then cooled again by lowering the voltage to about 9V. At this time, the maximum temperature of the cathode reaches up to 1050 ° C. (temperature measured by a pyrometer), and attention should be paid to the time management of the maximum temperature.

That is, the thermal activation process is to decompose and reduce the carbonate (6), BaCO ₃ , SrCO ₃ , Caco ₃ is the main component of the carbonate (6) BaO and CO ₂ , SrO and CO ₂ , SrO and CO ₂ , CaO and after CO ₂ is decomposed into each of CO ₂ has been removed, the remaining components causes the components of Mg, Si and the reaction of the cap (7) Ba and MgO, and SiO ₂ is in 2Si energetic free electrons is in state Ba ⁺⁺ It can be created.

On the other hand, the current activation process is performed after the above thermal activation process is completed, the voltage of the heater 8 is applied to about 9V, 8V to the electrode 1 of the electron gun, 260V to the electrode 2 is applied for about 1 hour Maintain state.

Accordingly, the current flows to the electrode to generate heat, and thus the degassing process is performed so that the electrode is clean and stable electron emission is possible.

However, even after such various processes, a difference occurs in electron emission characteristics depending on the structure of the cathode.

On the other hand, as a problem of the conventional negative electrode structure described above, in the case of the three-piece type negative electrode shown in Fig. 1A, since the holder 9 and the sleeve 2 are in surface contact with the entire 360 ° periphery, the heater 8 The conduction loss through the sleeve 2 of the heat supplied from the large, structurally large volume has a disadvantage that the thermal conductivity is slow. In addition, the sleeve 2 support holder 9 of the cathode structure is installed so as to extend only in the direction close to the electrode of the electron gun, so that the thermal expansion is large, resulting in a large overshoot.

On the contrary, in the case of the ribbon type cathode structure shown in FIG. 1B, the sleeve 10 and the support 1 are fixed by the ribbon 10, and thus the cross-sectional area of the ribbon 10 is small. Since the area is small, the conduction loss caused by the heat of the heater 8 being conducted to the support 1 can be suppressed, while the ribbon 10, which is the metal connector 3 between the sleeve 2 and the support 1, can be suppressed. ) Is easy to be damaged by an impact, and there are various disadvantages such as high copy loss.

The present invention is to solve the above problems, to improve the cathode structure of the electron gun for the cathode ray tube to improve the thermal efficiency of the cathode of the electron gun and at the same time minimize the overshoot due to thermal expansion of the cathode structure to implement stable electron emission of the cathode An object of the present invention is to provide a cathode structure of an electron gun for cathode ray tubes.

In order to achieve the above object, the present invention is a cathode structure of the electron gun for the cathode ray tube is fixed to both ends of the cone-shaped metal connector interconnecting the sleeve and the support at the top of the support and the bottom of the sleeve inserted into the support center. .

1 is a longitudinal cross-sectional view showing a cathode structure of a conventional electron gun electron tube,

Figure 1a is a front view of a three-piece type cathode structure

1B is a plan view and a front view of a ribbon type cathode structure;

Figure 2 is a front view showing a state in which the cathode structure according to the invention is assembled

3 is a plan view and a front view showing the combined state of FIG.

4 is a front view illustrating a state in which an anode structure is assembled according to another embodiment of the metal insulator of FIG. 2;

* Description of the symbols for the main parts of the drawings *

1: support 2: sleeve

3: cone-shaped metal connector 3a: straight portion

4a, 4b: Flare 5: Through

6: Carbonate 7: Cap

8: Heater 9: holder

10: Ribbon

Hereinafter, an embodiment of the present invention will be described in detail with reference to FIGS. 2 to 4.

2 is a front view showing a state in which the negative electrode structure according to the invention is assembled, Figure 3 is a plan view and a front view showing a combined state of Figure 2, Figure 4 is a negative electrode according to another embodiment of the metal connector of Figure 2 As a front view showing a state of assembling the structure, the present invention provides a cone-shaped metal interconnecting the sleeve 2 and the support 1 to the upper end of the support 1 and the lower end of the sleeve 2 inserted into the center of the support 1. Both ends of the connecting body 3 are fixed.

At this time, the upper end of the support (1) and the upper end of the cone-shaped metal connector (3) is formed so as to extend in the radial direction to form a freire (4a), (4b) coupled to each other.

In addition, the lower end of the cone-shaped metal connector (3) welded to the lower end of the sleeve 2 is coupled to form a straight portion (3a) does not change the radius in the axial direction.

In addition, the cone-shaped metal connector (3) is made of a Nichrome (NiCr) material of the same material as the sleeve (2).

On the other hand, the cone-shaped metal connector 3 may be formed with a plurality of through holes (5) for reducing the heat conduction loss by reducing the heat transfer cross-sectional area of the cone-shaped metal connector (3).

The operation of the present invention configured as described above is as follows.

Therefore, when assembling the negative electrode structure of the present invention, first, the cap 7 to be coated with the carbonate 6 and the sleeve 2 are combined, and then the cone-shaped metal connector 3 is placed under the sleeve 2. By inserting the outer peripheral surface of the lower end of the sleeve 2 and the inner peripheral surface of the lower end of the cone-shaped metal connector 3 is matched and welded.

At this time, the lower end of the cone-shaped metal connector 3 welded to and coupled to the lower end of the sleeve 2 is formed with a straight portion 3a having no radial change along the axial direction, thereby improving weldability.

Subsequently, the cone-shaped metal connector 3 is welded in a state in which the prere 4b formed at the upper end of the support 1 is aligned with the lower portion of the cone-shaped spore 4a extending radially on the upper end of the cone-shaped metal connector 3. ) And the support (1) to each other to complete the assembly of the cathode structure.

For example, the cap 7 of the anode structure of the present invention is composed of a side thickness of 0.05mm, a top thickness of 0.16mm, an inner diameter of 1.57mm, the sleeve 2 has a cylindrical length of about 6.5mm in total length, thickness (t) of 18μm The structure is made of Nichrome (NiCr).

In addition, the cone-shaped metal connector 3 has a flare 4a protruding by about 1 mm in length (l) at the upper end, and covers the upper part of the fryer 4b of the support 1, The straight inner circumferential surface having the length ₁ is welded to the outer circumferential surface of the bottom of the sleeve 2.

In particular, the material of the cone-shaped metal connector (3) is made of the same material as the sleeve (2) nichrome, the thickness is also manufactured in the same dimensions.

In addition, the ratio of the overall length of the sleeve 2 and the cone-shaped metal connector 3 is about 1: 0.6 to 1: 0.7.

Therefore, the electron gun negative electrode structure of the present invention configured as described above, unlike the ribbon 10 of the conventional ribbon 10 type negative electrode structure is easily damaged by the impact, the metal connector (3) is cone-shaped, so very rigid Because of the large geometry, impact resistance is enhanced.

In addition, as in the ribbon 10 type cathode structure, when the thermal expansion occurs due to the heat generated by the heater 8, the expansion direction of the sleeve 2 due to heat is the electrode (not shown) side in front of the cap 7 position. On the other hand, since the expansion direction of the metal connector 3 is opposite to the electrode, the amount of thermal expansion cancels each other, thereby reducing the phenomenon that the distance between the cathode structure and the electrode due to thermal expansion is closer.

For example, while the thermal expansion amount of the conventional negative electrode structure is 80 ~ 100μm, the expansion amount of the negative electrode structure according to the present invention is 40 ~ 50μm, so that the thermal expansion amount directly related to the overshoot is reduced by about 50%.

Accordingly, the present invention can minimize the overshoot, which is a transient characteristic of the output current, by preventing sudden changes in the gap between the electrode and the cathode structure due to thermal expansion during initial power-on, thereby quickly stabilizing the cathode current. Will be.

In addition, in the present invention, since the cone-shaped metal connector 3 is made of a nichrome material having low thermal conductivity similarly to the sleeve 2, the heat supplied from the heater 8 is conducted through the sleeve 2. On the other hand, the heater 8 is double shielded by the metal connecting body 3 and the sleeve 2, so that the radiation loss can be minimized.

That is, while the conventional cathode temperature is 770 ° C., it can be seen that the cathode temperature of the present invention is 800 ° C., so that the thermal efficiency of the heater 8 can be increased.

Accordingly, the present invention can improve the cathode thermal efficiency of the electron gun for cathode ray tube and minimize the overshoot due to thermal expansion, it is possible to implement a stable electron emission of the cathode.

As described above, the present invention improves the cathode structure of the cathode ray tube electron gun to suppress the conduction loss of the heat supplied from the heater 8 to improve the emission characteristics while overshoot due to thermal expansion of the sleeve 2 It is a very useful invention that the cathode current is stabilized quickly by canceling and canceling in the opposite direction by employing the cone-shaped metal connector 3.

Claims (5)

A cathode structure of an electron gun for a cathode ray tube, characterized in that both ends of the cone-shaped metal connector interconnecting the sleeve and the support are fixed to an upper end of the support and a lower end of the sleeve inserted into the center of the support. The method of claim 1, The cathode structure of the electron gun for cathode ray tube, characterized in that the top of the support and the top of the cone-shaped metal connector is formed in the radial direction extending in the direction of the coupling coupled to each other. The method of claim 1, Cathode structure of the electron gun for cathode ray tube, characterized in that the lower end of the cone-shaped metal connector is welded and coupled to the lower end of the sleeve is a straight portion without a radial change in the axial direction to facilitate welding. The method of claim 1, The cathode structure of the electron gun for cathode ray tube, characterized in that the material of the cone-shaped metal connector is made of nichrome material. The cathode structure of claim 1, wherein a plurality of through holes are formed in the cone-shaped metal connector to reduce heat conduction cross-sectional area, thereby reducing heat conduction loss.