KR20030062459A - Electron gun of Cathode Ray Tube - Google Patents

Abstract

PURPOSE: An electron gun for a cathode ray tube is provided to achieve improved voltage withstanding characteristics of electron gun by forming protrusions at the position where the shield tab is welded to the insulating support member. CONSTITUTION: An electron gun comprises a plurality of cathodes; heaters accommodated in the cathodes; an accelerating electrode spaced apart from a control electrode; first to fourth focusing electrodes; and an anode electrode where an anode voltage is applied. The electrodes are fixed by an insulating support member(30), and a shield tab is fixed at a certain part of the insulating support member. The part of the insulating support member where the shield tab is fixed has a protrusion(40) which is formed at the part where the shield tab is to be welded.

Description

Electron gun for cathode ray tube {Electron gun of Cathode Ray Tube}

The present invention relates to an electron gun of a cathode ray tube, and more particularly, by placing a shield tab in a protruding or recessed portion of the bead glass, thereby placing the shield tab in accordance with the stable withstand voltage characteristics and the position of the shield tab. The present invention relates to an electron gun for cathode ray tubes in which the high voltage charged on the electric field affects the electric field of the main lens electrode to minimize the distortion of the concentration of the three electron beams.

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

As shown, the conventional cathode ray tube has a panel 10 having a fluorescent surface 10a coated with R, G, and B fluorescent materials therein, and a funnel fusion-fixed with frit glass at the rear of the panel 10. (12), an electron gun (20) enclosed in a neck portion (12a) provided behind the funnel (12) and irradiating electron beams of R, G, and B, and the color of the electron beam on the rear inner surface of the panel (10). It includes a shadow mask 14 is formed with a plurality of slits for screening, and a frame assembly (not shown) for supporting the shadow mask (14).

The funnel 12 includes a deflection yoke 16 for deflecting the electron beam irradiated from the electron gun 20 up and down, left and right, and a traveling trajectory so that the electron beam accurately strikes the phosphor forming the fluorescent surface 10a. A magnet (not shown) is installed to prevent poor color purity.

2 shows a conventional electron gun, which is spaced apart from the cathode 21 by three cathodes 21, a heater 22 inserted into the cathode 21, and a cathode 21. The control electrode 23 which is a through structure of the three cathodes 21 arrange | positioned, the acceleration electrode 24 arrange | positioned at a predetermined distance from the said control electrode 23, and the 1st focusing electrode which comprises a 3 pole part ( 25), the same voltage as that of the acceleration electrode 24 is applied, and a voltage of 600 to 1200V is normally applied, and the second focusing electrode 26 for unidirectional multi-stage focusing is separated from the quadrupole lens to form a dynamic voltage. And the third focusing electrode 27 to which the static voltage is applied, the fourth focusing electrode 28 and the anode electrode 29 to which the anode voltage is applied are sequentially arranged.

Cathode ray tube having the structure as described above should maintain a certain degree of vacuum through the exhaust process to improve the electron emission characteristics and withstand voltage characteristics, and the degree of vacuum after exhaust through the exhaust process should be 5 × 10 ^-6 torr. . The cathode ray tube subjected to the exhaust process is subjected to getter flashing in order to remove residual gas which is not completely removed during the exhaust process. The material of the getter is barium (Ba), and thus the barium (Ba) The film forms and absorbs residual gas. However, the degree of vacuum during getter flashing increases to 5 × 10 ^{−4 to −5} torr as the gases of the getter itself are released.

The getter flashing is completed, the cathode ray tube undergoes an aging process in order to emit electrons from the electron gun 20, and heat activation for heating the heater 22 by stepwise heating for 5 to 11 V for about 10 minutes. AC 9V to the heater 22, DC 8V to the control electrode 23, DC260V to the acceleration electrode 24 is applied to the current activation to stabilize.

When the above process is performed, the carbonate attached to the upper portion of the cathode 21 is decomposed and active electron emission is possible. When the rated voltage is applied to each electrode of the electron gun embedded in the completed cathode ray tube, first, when the heater 22 built in the cathode receives power from the stem pin and generates heat, the temperature of the cathode is about 800 ° C. By this heat, hot electrons are emitted from the cathode 21. The electrons are controlled by the control electrode 23, and the accelerating electrode 24 and the first focusing point to which a voltage of about 500 to 1000 V is applied. The electron beam is accelerated by the electrode 25, passes through a pre-focus lens that becomes the primary focusing, and the second focusing electrode 27 in which the second focusing electrode 26 and the quadrupole lens are formed. ), The fourth focusing electrode 28 serving as the main lens forming electrode, and the accelerating electrode 24 to which a high voltage of 24 to 30 kV is applied are sequentially passed to collide with the fluorescent surface 10a to emit light. Here, the first, third, and fourth focusing electrodes 25, 27, and 28 serve to focus the electron beam by applying a voltage of 22 to 30% of the high voltage applied to the acceleration electrode 24.

When the cathode ray tube is in normal operation, a high voltage of 24 to 30 kV applied to the acceleration electrode 24 flows down through the insulating support 30 in which each electrode is fixed and fused, that is, bead glass, and the cathode 21 and the control electrode ( 23), the acceleration electrode 24 is damaged to act to inhibit the normal operation of the cathode ray tube.

In order to block this, the shield tab 31 is connected to the insulating support 30 and the shield tab 31 is formed on the insulating support 30 on which the neck 12a inner wall and the shield tab 31 are located through sputtering during the manufacturing process of the cathode ray tube. 31) By depositing the components to prevent damage to these cathode ray tubes.

The structure as described above may prevent some damage to the cathode ray tube, but the position of the shield tab 31 increases the damage of the cathode ray tube, that is, the withstand voltage characteristics are not good, and are charged along the insulating support 30. The high voltage affects the electric field between the third focusing electrode 27 and the acceleration electrode 24, which are the main lens forming electrodes, so that the STC drift characteristic in which the concentration of the three electron beams shifts with time is not good.

Sputtring at the position of the current shield tab 31 to deposit the metal component 31a of the shield tab component on the inner wall of the neck 12a to serve as a capacitor to block the flow of charged high voltage along the insulating support 31. Although the degree is weak, there is a problem in the reliability of the above characteristics.

That is, the charged potential in the conventional electron gun shown by the solid line in FIG. 3 affects the electric field of the main lens, so that the STC Drift characteristic in which the concentration of the three electron beams shifts with time is not good, and the amount of STC Drift in the conventional electron gun is It is usually at a level of 0.10 to 0.14, which is a significant inhibitor to the resolution characteristics of the cathode ray tube.

In addition, the potential charged to the right side of the shield tab 31 (bead glass surface) also impacts the accelerating electrode 24 and the second focusing electrode 26 to which a voltage of 500 to 1000 V is applied to the cathode 21. It is an unstable condition that can damage, causing serious problems with the reliability of cathode ray tubes. That is, the problem is particularly serious in the connection structure of the electron gun for the multi-stage convergence of the UB, in which the acceleration electrode 24 and the second focusing electrode 26 are connected to each other. 23) is located at a distance of only 0.10 to 0.15mm, and the cathode 21 is also at a position of 0.08 to 0.12mm with the control electrode 23, so that the impact on the second focusing electrode 26 by a spark or the like Will cause damage to the cathode.

Accordingly, the present invention has been made to solve the above problems, by providing a projecting portion in the position where the shield tab is welded to the insulating support to each electrode fusion-fixed, to provide an electron gun to improve the withstand voltage characteristics of the electron gun The purpose is.

1 is a view showing a conventional cathode ray tube,

2 is a view showing an electron gun of a conventional cathode ray tube,

3 is a view for showing the position of the shield tab in the electron gun of the conventional cathode ray tube,

4 is a view showing an electron gun of a cathode ray tube according to the present invention;

5 is a view showing the main portion of the electron gun for cathode ray tube according to the present invention,

6 is a view showing the electric potential charged between the neck inner wall and the electron gun insulation support in the electron gun of the prior art and the present invention,

7 is a view showing the characteristics of the cathode ray tube according to the height of the protrusion formed on the insulating support according to the invention,

Explanation of symbols on the main parts of the drawings

12a; Neck

20; Electron gun 21; cathode

22; Heater 23; Control electrode

24; Acceleration electrode 25; First focusing electrode

26,27,28; Second, third and fourth focusing electrodes 29; Anode

30; Insulating support 31; Shield tap

31a; Metal component 40; projection part

The electron gun of the cathode ray tube according to the present invention for achieving the above object is composed of a plurality of cathodes and a plurality of electrodes for controlling and accelerating the electron beam generated from the cathode and the heater is inserted therein, the electrodes The shield tab is fixed by an insulating support and a shield tab is fixed to a portion of the insulating support, and a protrusion is formed on a portion of the insulating support on which the shield tab is fixed, and a shield tab is provided on the protrusion.

Hereinafter, with reference to the accompanying drawings will be described in more detail the configuration and operation of the electron gun for cathode ray tube according to the present invention.

5 is a view showing an electron gun of the cathode ray tube according to the present invention, Figure 6 is a view showing in detail the main portion of the electron gun of the cathode ray tube according to the present invention, Figure 7 is a characteristic of the cathode ray tube according to the electron gun according to the present invention Figure is shown.

As shown in FIG. 5, a control electrode which is a through structure of three cathodes 21, a heater 22 inserted into the cathode, and three cathodes 21 disposed at a predetermined distance from the cathode 21. Acceleration electrodes 24 arranged at regular intervals in (23), first focusing electrodes 25 constituting the three poles, and multi-stage uni-directional focusing are applied to the same voltage as the acceleration electrodes, and a voltage of 600 to 1200V is normally applied. A second focusing electrode 26 to be applied, a third focusing electrode 27 and a fourth focusing electrode 28 separated from each other to form a quadrupole lens and to which a dynamic voltage Vfd and a static voltage Vfs are applied; The anode electrodes 29 to which the anode voltage is applied are sequentially arranged to have a structure fixed by bead glass, which is an insulating support 30.

An anode voltage of 24 to 30 kV is applied to the anode electrode 29. The insulating support 30 has a structure in which a protrusion 40 is formed at a portion to which the shield tab 31 is to be welded, and the shield tab 31 is positioned at the protrusion 40.

Typically, the shield tab 31 is installed at a position where the third and fourth focusing electrodes 27 and 28 are fused, and the closer the position of the shield tab 31 is to the anode electrode 29, the insulated support 30 is provided. The high voltage charged on the electric field affects the electric field of the main lens electrode, resulting in an increase in the convergence degree of the three electron beams (STC Drift). The closer to the second focusing electrode 26, the more charged the insulating support 30 is. When the high voltage is applied to the electrode to which the low voltage is applied, a problem occurs in the breakdown voltage.

Therefore, in the present invention, the projection 40 having a height of about 0.15 to 0.5 mm is formed on the insulating support 30 to which the shield tab 31 is welded, so that the characteristics of the cathode ray tube are best represented. That is, as shown in Figure 5, it can be seen that the charge potential of the insulating support 30 of the present invention shown by the dotted line is lower than the charge potential of the conventional insulating support represented by a solid line.

That is, after the cathode ray tube manufacturing process, the metal component 31a is formed on the wall surface of the neck 12a of the shield tab 31. Since the metal component 31a serves as a condenser, the shield tab 31 and the neck are usually formed. (12a) The closer the metal component 31a of the wall surface is, the larger the capacitance becomes, so that the voltage charged on the insulating support 30 is lower than that of the conventional electron gun.

FIG. 6 shows the breakdown voltage according to the height of the protrusion 40 formed on the insulator support 30 of the electron gun according to the present invention, and the degree of focusing of the three electron beams with the amount of time shifted (STC Drift). A graph showing the results of experimenting with the relationship

A typical cathode ray tube having an outer diameter of 29.1 mm in the neck has a distance of about 1.4 mm between the inner wall of the neck and the insulation support, and the height of the protrusion of the electron gun insulation support of the cathode ray tube according to the present invention is 3 on the X axis and 3 on the left of the Y axis on the graph. The focusing degree of the electron beam shows the amount of STC drift shifted with time, and the right side of the Y axis shows discharge characteristics, that is, one of the reliability characteristics of the cathode ray tube, that is, the G2-based stray starting voltage.

As a result, the STC Drift is 0.08 mm or less, as shown by the bar graph shown in FIG. 6, and the breakdown voltage is the attachment position of the shield tab 31 bonded to 7 kV or more, as shown by the dot graph of FIG. It can be seen that the height (H) of the protruding portion 40 formed in the insulating support 30 to make a 0.15 ~ 0.5mm. The protruding portion H is formed at a position of 0.1 to 0.33 of the distance W between the insulating support 30 and the inner surface of the neck 12a.

That is, in the conventional electron gun, since there is no portion protruding from the insulating support, H = 0, and the G2-based withstand voltage characteristic does not matter. The amount of STC Drift is 0.1 ~ 0.14mm, which is out of 0.08mm which is the STC Drift management level of cathode ray tube, which is a problem for cathode ray tube resolution.

When the height of the protrusion 40 formed on the insulating support 30 is higher than a predetermined level, the capacitance between the portion of the metal component 31a on the inner wall of the neck 12a and the shield tab 31 increases, but the charging voltage of the positive voltage This is absorbed a lot, rather a reverse action is generated a phenomenon that the withstand voltage characteristics are disadvantageous, causing problems in the reliability characteristics of the cathode ray tube.

As described above, according to the present invention, by forming a part of the insulating support to which the shield tab is welded, the stopper is attached to the end of the bead glass when the insulating support is melted and fixed to each electrode during the manufacturing process of the electron gun. Shape deformation of foreign materials or insulation support does not occur, so the breakdown voltage due to cleanliness can be improved, and the quality of the product can be improved.

Claims (3)

Comprising a plurality of cathodes having a heater inserted therein and a plurality of electrodes for controlling and accelerating the electron beam generated from the cathode, the electrodes are fixed by an insulating support and a shield tab is fixed to a portion of the insulating support, A protruding portion is formed in a portion of the insulating support to which the shield tab is fixed, and a shield tab is provided in the protruding portion, wherein the electron gun for the cathode ray tube is used. The electron gun for cathode ray tube according to claim 1, wherein the height H of the protruding portion is 0.15 to 0.5 mm in the neck direction of the insulating support. The electron gun for cathode ray tube according to claim 1, wherein the protruding portion is formed so as to be located at a position of 0.1 to 0.33 of a distance (W) from the neck inner surface of the insulating support.