KR100394033B1 - Electronic gun for cathode ray tube - Google Patents

Abstract

An electron gun for a cathode ray tube, the method comprising: at least one cathode emitting an electron beam, a control electrode, a first focusing and accelerating electrode, a second focusing and accelerating electrode, and an electrode forming a main lens, and a shield for preventing damage to the electrodes In the cathode ray tube electron gun including the tab, the shield tab is installed at a position that satisfies the resolution and withstand voltage characteristics simultaneously from the main lens to the cathode direction, thereby improving the cathode ray tube characteristics and improving the quality, as well as future development. It can be used as a criterion for providing a basis for designing a large-scale, high-resolution cathode ray tube.

Description

Electron gun for cathode ray tube {ELECTRONIC GUN FOR CATHODE RAY TUBE}

The present invention relates to a cathode ray tube, and more particularly to an electron gun for cathode ray tube.

As shown in FIG. 1, a cathode ray tube according to the related art uses a panel 1 having a fluorescent surface coated with a fluorescent material of R / G / B inside and a frit glass behind the panel 1. The outer skeleton is made of a funnel (2) to be fused.

In the neck portion 31 of the funnel 2, an electron gun 10 for irradiating the R / G / B tricolor electron beam 20 is enclosed.

Subsequently, the rear inner surface of the panel 1 includes a shadow mask 3 composed of a plurality of slits for selecting colors of the electron beam 20 and a frame assembly (not shown) for supporting the shadow mask 3.

In addition, the funnel 2 includes a deflection yoke 5 for deflecting the electron beam 20 up / down, left / right, and a color purity defect by modifying a traveling trajectory so that the electron beam 20 strikes the phosphor 4 accurately. A correction magnet (not shown) is provided to prevent the damage.

In addition, as shown in FIG. 2, the detailed structure of the electron gun 10 includes three independent cathodes 11 and three control electrodes 12 which are three cathode through-hole structures arranged at a predetermined distance from the cathode 11. ), The first acceleration electrode 13 disposed at a predetermined distance from the control electrode 12, the first focusing electrode 14, and the second acceleration electrode 15 for multistage focusing of the UB. The second focusing electrode 16-1, the third focusing electrode 16-2, the fourth focusing electrode 17, and the anode 18 are sequentially arranged, the heater 19 for activation and the stem pin. (6) and bead glass 21, which is an insulating support in which each electrode is fixed and fused, is provided. In addition, a high voltage applied to the accelerating electrode is charged along the bead glass 21, so that the spark as accumulated accumulates the three-pole electrode and the cathode 11 to prevent damage to the cathode ray tube (shield tab) 30 is installed on the bead glass 21.

In this case, the static voltage Vfs is applied to the second focusing electrode 16-1, and the dynamic voltage Vfd is applied to the first focusing electrode 14, the third focusing electrode 16-2, and the fourth focusing electrode 17. Is applied.

The inside of the cathode ray tube has to maintain a certain degree of vacuum through the exhaust process to improve the electron emission characteristics and withstand voltage characteristics. The vacuum degree after the exhaust process should be 5 × 10 ^-6 Torr, and 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 it is barium (Ba), a barium film is formed on the inner wall of the cathode ray tube and at the same time, the residual gas is absorbed.

However, the degree of vacuum in the getter fleshing process rises ^to 5 × 10 ^{-4 to -5} Torr as the gases in the getter itself are released.

As described above, the getter flushing completed cathode ray tube undergoes an aging process to emit electrons from the electron gun, and heat activation for heating the heater 19 by 5 to 11 V for about 10 minutes using a stepwise heating method, and the heater 19 AC 9V, DC 8V to the control electrode 12, and DC 260V to the first acceleration electrode 13 are applied to stabilize the current activation.

Through the above-described process, the carbonate attached to the upper portion of the cathode 11 is decomposed and smooth electron emission is possible.

The operation of the cathode ray tube configured as described above is as follows.

First, when a rated voltage is applied to each electrode of the electron gun 10, the heater 19 embedded in the cathode 11 receives the power (6.3V) from the stem pin 6 to generate heat to generate the temperature of the cathode 11. It is about 800 degreeC. The heat electrons are emitted from the cathode 11 by the heat, and the electrons 20 are controlled by the control electrode 12, and the first acceleration electrode 13 and the first focusing electrode to which about 600 to 1200 V are applied. Accelerated by 14 passes through the prefocus lens.

Subsequently, the second accelerating lens 15, the second focusing electrode 16-1, the third focusing electrode 16-2, the fourth focusing electrode 17, and the fourth focusing electrode 17 formed with the quadrupole lens are formed as the main lens forming electrode. The light is emitted by colliding with the fluorescent surface 4 by sequentially passing through the three focusing electrodes 16-2 and the anode 18 to which a high voltage of 24 to 30 kV is applied.

At this time, when the cathode ray tube is normally operated, a high voltage of 24 to 30 kV applied to the anode 18 flows down through the bead glass 21 in which the electrodes are fixed and fused to form the cathode 11, the control electrode 12, and the first electrode. 1 may cause damage to the accelerating electrode 13 to inhibit the normal operation of the cathode ray tube.

Therefore, the shield tab 30 is deposited on the bead glass 21 in which the inner wall of the neck portion 31 and the shield tab 30 are positioned through sputtering during the manufacturing process to prevent damage to the cathode ray tube. To do so.

At this time, looking at the attachment position of the shield tab 30, the distance to the second focusing electrode 16-1, the third focusing electrode 16-2 and the fourth focusing electrode 17 is referred to as 'L' and the fourth focusing When the distance from the electrode 17 to the shield tab 30 is 'X', the existing diameter Φ is 29.1 and the 15-inch CDT electron gun has an X / L of 0.47, a diameter of 29.1 and 19 inches. The gun for the CDT is 0.68 in X / L, the diameter is 29.1, the gun for the 17-inch CDT is 0.81 in X / L, the diameter is 32.5, and the gun for the 32-inch CDT is 0.45. Was used.

Thus, the characteristics of the cathode ray tube appears different depending on the installation position of the shield tab (30).

That is, when the position of the shield tab 30 is close to the third acceleration electrode 18, the high voltage charged along the bead glass 21 is blocked in advance, so that the withstand voltage characteristics of the cathode ray tube become stronger, but the cathode 11 and the control electrode are strong. (12) and the first acceleration electrode (13) can be damaged by damaging the normal operation of the cathode ray tube, but because it affects the main lens electric field, the STC drift characteristics are deteriorated, that is, the degree of focusing of the three electron beams As the amount shifts with time, the resolution characteristic of the cathode ray tube becomes worse.

On the other hand, when the position of the shield tab 30 is located close to the second acceleration electrode 15 side, since the high voltage charged along the bead glass 21 may not be blocked in advance, the shield tab 30 is lowered to the side closer to the cathode 11. The cathode 11, the control electrode 12, and the first acceleration electrode 13 are susceptible to damage and the breakdown voltage characteristics of the cathode ray tube are weakened, while being charged along the bead glass 21. Since the cutoff position of the high voltage is far below the main lens field forming position, the influence on the main lens field is weakened, so that the STC drift characteristic is improved.

Such a characteristic change according to the installation position of the shield tab 30 is shown in FIG. 3.

In other words, the effect on the main lens electric field is that when the shield tab 30 is in the 'A' position, the influence of the charge potential is higher than that of the 'B' position, and the change factor of the charging potential with time is taken into consideration. If so, it can be said that the STC Drift amount is large. On the other hand, when the shield tab 30 is in the 'B' position, since the charging potential near the cathode 11 is high, there is a high risk of damage to the cathode due to discharge, which may cause a problem in the reliability of the cathode ray tube. have.

The cathode ray tube according to the related art has a shield tab installed to prevent damage to the cathode ray tube, but the STC drift characteristics are deteriorated, that is, the resolution characteristics are deteriorated or the withstand voltage characteristics are reduced, that is, components such as electrodes, depending on the installation position of the shield tab. There is a problem that can cause damage.

Accordingly, an object of the present invention is to provide an electron gun for a cathode ray tube provided with a shield tab at a position capable of simultaneously satisfying resolution and withstand voltage characteristics.

1 is a cross-sectional view showing the structure of a typical cathode ray tube

Figure 2 is a cross-sectional view showing an electron gun for a cathode ray tube according to the prior art

3 is a view showing a potential change according to a shield tab installation position according to the prior art;

4 is a cross-sectional view showing an electron gun for a cathode ray tube according to the present invention.

5 is a graph showing the STC drift amount and the Stray start voltage change according to the shield tap position

Explanation of symbols for main parts of the drawings

11: cathode 12: control electrode

13: first acceleration electrode 14: first focusing electrode

15: second acceleration electrode 16-1: second focusing electrode

16-2: third focusing electrode 17: fourth focusing electrode

18: anode 19: heater

21: Bead glass 30, 40: Shield tab

The present invention includes at least one cathode that emits an electron beam, an electrode forming a control electrode, a first focusing and accelerating electrode, a second focusing and accelerating electrode, and a main lens, and a shield tab for preventing damage to the electrodes. In the electron gun for cathode ray tube, the length of the length from the second focusing electrode to the main lens inlet is 'L', and the shield tab is installed at a position 'X' in the direction of the cathode from the main lens inlet, and 'X / L' It is characterized in that it is in the range of 0.50 to 0.63.

Hereinafter, a preferred embodiment of a cathode ray tube electron gun according to the present invention with reference to the accompanying drawings in detail as follows.

4 is a cross-sectional view showing an electron gun for a cathode ray tube according to the present invention, Figure 5 is a graph showing the STC Drift amount and the Stray start voltage change according to the shield tap position.

As shown in FIG. 4, the electron gun for the cathode ray tube according to the present invention includes three cathodes 11 that are independent of each other, and a control electrode 12 that is three cathode through-hole structures disposed at a predetermined distance from the cathode 11. In addition, the acceleration electrode 13 disposed at a predetermined distance from the control electrode 12, the first focusing electrode 14, the second accelerating electrode 15, the second focusing electrode 16-1, and the third focusing electrode (16-2), the fourth focusing electrode (17), and the third accelerating electrode (18) are sequentially arranged, and the heater 19, the stem pin 6, and the electrodes are fixedly fused together for activation. Bead glass 21, which is an insulating support, is provided. In addition, a high voltage applied to the accelerating electrode is charged along the bead glass 21, so that the spark as accumulated accumulates the three-pole electrode and the cathode 11 to prevent damage to the cathode ray tube (shield tab) 40 is installed on the bead glass 21.

In this case, the static voltage Vfs is applied to the second focusing electrode 16-1, and the dynamic voltage Vfd is applied to the first focusing electrode 14, the third focusing electrode 16-2, and the fourth focusing electrode 17. Is applied.

According to the present invention, the shield tab 40 is disposed at a position that satisfies the resolution characteristic, that is, the STC drift characteristic and the withstand voltage characteristic simultaneously. The second focusing electrode 16-1 and the third focusing electrode 16-2 are provided. And a distance from the fourth focusing electrode 17 to 'L' and a distance from the fourth focusing electrode 17 to the shield tab 30 is 'X', an attachment position of the shield tab 40. X 'was set in the range which X / L satisfy | fills 0.50-0.63.

At this time, the second, third and fourth focusing electrodes 16-1, 16-2, and 17 except for the first focusing electrode 14 and the second accelerating electrode 15 when setting the shield tab 40 are installed. The second acceleration electrode 15 has a second acceleration electrode 15 in the direction of the cathode of the second focusing electrode 16-1, and a voltage of 600 to 1200 V is applied to the second focusing electrode 16-1. 16-1) (16-2), because the voltage applied to the 6 ~ 8 kV has a significant potential difference, the resulting breakdown voltage characteristics can be a problem, and also the voltage applied to the anode 18 This is because the withstand voltage characteristic due to the potential difference between each other may be a problem when considering the point of ~ 30kV.

The STC drift characteristic and withstand voltage (Stray start voltage) characteristics of the cathode ray tube according to the present invention will be described with reference to the graph of FIG. 5.

FIG. 5 is a graph showing changes in STC drift and breakdown voltage depending on the shield tab attachment position when the total lengths of the second, third and fourth focusing electrodes 16-1, 16-2, and 17 of the electron gun are 26 mm. The X axis represents the length, the left side of the Y side is the amount of STC drift, and the right side of the Y axis shows the breakdown voltage (Stray start voltage) characteristics.

As shown in the graph, the attachment position X of the shield tab 40 suitable for the level of less than 0.08 mm, which is a general characteristic satisfaction level of the STC drift amount, and the level of withstand voltage of 7 kV or more is 13.0 ~ from the fourth focusing electrode 17 side. As 16.4 mm, considering the total length of 26 mm of the second, third and fourth focusing electrodes 16-1, 16-2 and 17, the X / L is 0.50 to 0.63.

That is, when the shield tab 40 is attached at this position, the withstand voltage characteristic and the STC drift amount characteristic can be satisfied at the same time.

The electron gun for cathode ray tube according to the present invention is to install the shield tab at the position that satisfies the withstand voltage characteristics and STC drift characteristics at the same time, as well as the effect of improving the cathode ray tube characteristics, quality improvement, large size, high resolution cathode ray tube design to be developed in the future It can be used as a standard for laying the basis of

Claims (1)

At least one cathode emitting an electron beam, a control electrode, a first focusing and accelerating electrode, a second focusing and accelerating electrode, and an electrode forming a main lens, and a shield tab for preventing damage to the electrodes; To The length of the length from the second focusing electrode to the main lens inlet is 'L' and the shield tab is installed at a position 'X' in the direction of the cathode from the main lens inlet, and 'X / L' is 0.50 to 0.63. Electron gun for cathode ray tube, characterized in that within the range.