KR20010063327A - Electron gun assembly for CRT - Google Patents

Abstract

PURPOSE: Disclosed is an electron gun structure for a cathode ray tube capable of enhancing the white balance characteristic and removing the brightness difference during the initial operation by uniformly setting the gap between the individual cathode and the control electrode. CONSTITUTION: In the inline type electron gun, cathodes(1) of R, G, B are welded to an eyelet(12), respectively. Control electrodes(2) for controlling a quantity of electron beam are positioned above the cathodes(1), respectively. The eyelet(12) comprises the first guide(12a) which is outwardly rounded at an upper end thereof along the circumferential direction and the second guide(12b) protruding from the first guide toward the control electrodes(2). The second guide(12b) is formed at the eyelet(12) which is welded to the cathodes(1) positioned at the outer periphery among the cathodes(R, G, B). The second guide(12b) can be formed at the both ends of the eyelet(12) in order to store the heat of the cathodes(1).

Description

Electron gun assembly for cathode ray tube {Electron gun assembly for CRT}

The present invention relates to an electron gun for a cathode ray tube, and more particularly to an electron gun structure for cathode ray tube to improve the white balance characteristics by implementing the same amount of thermal expansion of each of the initial operation R, G, B cathode.

In general, cathode ray tubes are the most widely used display devices for observation of oscilloscopes and radars as well as television receivers.

The cathode ray tube requires an electron gun capable of achieving a stable electron beam convergence because an electron beam radiated from the electron gun strikes the fluorescent film inside the screen to display an image.

For this purpose, three cathodes R, G, and B, which emit hot electrons, are arranged side by side, and the hot electrons are made into thin electron beams to accelerate at a high speed, and several electrodes for focusing on the fluorescent film inside the screen are processed by the electron beam. In-line electron guns arranged in a line along the direction are mainly applied.

Such an inline electron gun is shown in FIG. 1, which will be described as an example of an electron gun for a color cathode ray tube in the prior art.

A control electrode for controlling, accelerating and concentrating the hot electrons radiated from the negative electrode 1 to an electron beam having a speed and focusing power so as to land on the fluorescent film in a predetermined temperature range ( 2), an acceleration electrode 3, a focusing electrode 4, and an anode 5, and the cathode 1 and each of the electrodes 2 to 5 are separated by a predetermined distance by the bead glass 6, which is an electrical insulator. They are arranged one after another in a state.

When power is applied in this state and hot electrons are radiated from the cathode 1, the hot electrons pass through the control electrode 2, the acceleration electrode 3, the focusing electrode 4, the anode 5, and the like at a constant speed and It becomes an electron beam with intensity and can display a landing and an image on a screen.

Here, the cathode 1 is the first source of the electron beam, and occupies a very important gravity in the radiation characteristics of the electron beam.

The cathode 1 is divided into an oxide cathode and an impregnated cathode according to the material of the electromagnetic radiation. The impregnated cathode has a disadvantage of high operating temperature, high power consumption, and use of expensive materials. Therefore, an oxide cathode is mainly used for the cathode ray tube.

FIG. 2 illustrates a general oxide cathode and a bonding state thereof, wherein the oxide cathode is formed at one end of a cylindrical sleeve 8 into which a heater 7, which is a heat source, is inserted, and a tip of the sleeve 8. The main component is nickel (Ni), and is applied to the base metal (9) containing trace amounts of activated metals such as magnesium (Mg) and silicon (Si), and the upper surface of the base metal (9), and contains at least barium oxide (BaO). An electron-emitting material 10 of an alkaline earth metal composite oxide and a holder 11 provided outside the sleeve 8 to support the sleeve 8 are provided.

In addition, the eyelet 12 having the flange 12a formed at the upper end to block radiant heat is welded to a predetermined portion of the holder 11 to support the entire cathode 1, and the bead supporter welded to the eyelet 12 ( The end 13 is supported and fixed to the bead glass 6 to serve to support the cathode 1 to the bead glass 6.

In the cathode 1 according to the related art configured as described above, when the power is applied to the heater 7 from a stem pin, not shown in the drawing, the heat is generated, the base metal 9 of the cathode 1 is heated by this heat. The hot electrons are emitted from the electron radiating material 10.

The hot electrons are controlled, accelerated, and focused while passing through the electrodes 2 to 5 of the electron gun to form an electron beam having a speed and focusing force that can hit the fluorescent film.

Here, in order for the hot electrons to be smoothly radiated from the electron emitting material 10, the cathode 1 needs to be exhausted to have a predetermined degree of vacuum, and then the electron emitting material 10 must be activated.

The electrospinning material 10 first applies an alkali earth metal carbonate suspension onto the base metal 9 and is heated by the heater 7 during the exhaust process so that the alkaline earth metal carbonate is converted into an alkaline earth metal oxide.

Thereafter, a portion of the alkaline earth metal oxide is reduced at high temperature to activate the semiconductor property.

In this way, a reducing element such as silicon (Si) or magnesium (Mg) contained in the base metal 9 is moved to the interface between the alkaline earth metal oxide and the base metal 9 by diffusion, so that the alkaline earth metal oxide and the chemical Will react.

As a result, the electron-emitting material 10 becomes an oxygen-deficient semiconductor in which a part of the alkaline earth metal oxide is reduced, and the emission current is obtained under normal conditions of 700 to 800 ° C.

If this process is described by taking BaCO ₃ which is a representative material of the electron-emitting material 10 as an example ① to ④ below.

① BaCO ₃ → BaO + CO ₂ (absorbed by getter)

② 4BaO + Si → 2Ba + Ba ₂ SiO ₄

③ BaO + Mg → Ba + MgO

④ Ba → Ba ²⁺ + 2e (generating electrons)

As described above, the alkaline earth metal oxide, which is an electron-emitting material 10, is an alkaline earth metal whose main component is free barium (Ba) by chemical reaction with an activated metal in the gas metal 9, for example, magnesium (Mg) or silicon (Si). It can be seen that the free electrons are generated and the hot electrons are generated from the alkaline earth metal free atoms.

On the other hand, the cutoff voltage Ekco of the negative electrode 1 is an important characteristic that serves as a reference point of the operation of the water tube, and the applied voltage of the negative electrode 1 that does not emit hot electrons while the electron gun is thermally stable is the cutoff voltage of the negative electrode. Will be set. That is, the cutoff voltage of the cathode 1 refers to the cathode voltage when the screen disappears while the voltages of the control electrode 2 and the acceleration electrode 3 are fixed, and the cathode 1 is cut off at the cutoff voltage of the cathode 1. By applying a voltage to the potential difference with the acceleration electrode 3, the amount of electron beam emitted from the electron gun can be controlled.

In addition, the cutoff voltage of the negative electrode 1 is the distance d1 between the electron-emitting material 10 of the negative electrode 1 and the control electrode 2, the distance d2 between the control electrode 2 and the acceleration electrode 3, It is determined by the pore diameter D of the control electrode 2, the thickness t of the control electrode 2, and the voltage Ec2 applied to the acceleration electrode 3.

In order to realize stable radiation characteristics of the cathode 1, the cutoff voltage of the cathode 1 must be kept constant at each of the R, G, and B cathodes 1R, 1G, and 1B. If the cut-off voltage of the product becomes out of the standard (a certain range) and becomes poor, the white balance of the screen may be shifted during the initial screen operation, as well as adversely affecting the radiation characteristics of the cathode 1.

The cutoff voltage Ekco of the negative electrode 1 is represented by the following formula (1).

[Equation 1]

Remarkable in relation to the cut-off voltage is the overshoot characteristic, basically a heat of 700 ~ 800 ℃ is required to radiate hot electrons from the electron-emitting material 10 of the cathode (1), and most of these phenomenon The overshoot phenomenon occurs in the cathode 1 of.

That is, the heat is received from the initial operation heater 7 of the cathode 1 and the heat is conducted to the sleeve 8 and the holder 11 is thermally expanded in the upward direction, thereby the electrospinning material of the cathode 1 (10) and the control electrode (2) are so close to each other that the excessive phenomenon of excessive emission of electrons is generated from this.

In addition, the phenomenon in which the current of the cathode 1 rises and falls momentarily during initial operation is generally a desirable characteristic.

This overshoot phenomenon occurs early in operation at most cathodes 1, and a stable overshoot phenomenon is closely related to the stable radiation characteristics of the cathode 1.

Therefore, the factor that most affects the cutoff voltage of the cathode 1 may be referred to as the interval between the electron-emitting material 10 of the cathode 1 and the control electrode 2, and the cutoff voltage of the cathode 1 is determined. In order to achieve a stable implementation, the electron radiating material 10 and the control electrode 2 must maintain a predetermined interval displacement value, as well as the electron radiating material (R, G, and B cathodes 1R, 1G, and 1B). The amount of gap displacement between 10) and the control electrode 2 should be the same.

In the conventional inline type electron gun, the eyelets welded to the cathodes of R, G, and B each have the same shape. As shown in FIG. 3, a flange for suppressing heat radiation to the control electrode is formed near the electron-emitting material of the cathode. That is it.

However, since the cathodes of R, G, and B are located at the center in the position as shown in FIG. 4, in the outer R and B cathodes, heat is radiated to the outside, whereas in the G cathodes in the center, the surrounding R and B Heat dissipation is not easy in the state blocked by the cathode.

Therefore, since the R cathode and the B cathode of the outer portion are relatively lower in temperature than the G cathode of the center, the operation initial overshoot amount is small while the operation G over the center is larger than the other cathode.

That is, the outer R and B cathodes have a small amount of thermal expansion to the initial control electrode while the central G cathode has a large amount of thermal expansion to the initial control electrode, which causes the gap Dg between the G cathode and the control electrode. As the distance between the R and B cathodes and the control electrode is closer to the distance Dr (Db), the cutoff voltage at the G cathode is higher than that of the other cathodes. Thus, as shown in FIG. It is lower than the cathode current of the R and B beams.

As described above, when the cutoff voltages of the cathodes are changed, the white balance characteristic is deteriorated on the screen to cause color shift, as well as the cathode current difference of each beam is large, and thus the luminance may be changed during the initial operation.

Accordingly, the present invention has been proposed in view of this point, and the white balance characteristics are improved by making the cathode currents of each of the R, G, and B beams the same by equalizing the distance between the cathodes and the control electrodes. An object of the present invention is to provide an electron gun structure for a cathode ray tube that realizes a reliable image without difference in luminance during initial operation.

1 is a configuration diagram of an electron gun for a typical cathode ray tube,

2 is a cross-sectional view of a conventional cathode,

3 is a block diagram of a conventional eyelet,

Figure 4 is a comparison of the thermal expansion amount between each conventional cathode,

Figure 5 is a graph showing the change of each conventional cathode current,

6 is a cross-sectional view of the coupling of the negative electrode according to the present invention,

7 is a block diagram of an eyelet according to the present invention,

8 is a comparative view of the thermal expansion amount between each cathode according to the present invention,

9 is a graph showing the change of each cathode current according to the present invention.

*** Explanation of symbols for main parts of drawing ***

1: cathode 7: heater

8: sleeve 9: gas metal

10: electromagnetic radiation material 11: holder

12: eyelet 12a: flange

12b: Guide

Electron gun structure for a cathode ray tube according to the present invention for achieving this purpose, the cathodes of R, G, B are arranged side by side in a state welded to each eyelet, the control electrode for controlling the electron beam amount on the upper portion of the cathode In this positioned inline electron gun:

The eyelet is,

(1) a first guide bent outward along the circumferential direction at the upper end; And

(2) It characterized by including a 2nd guide which protrudes continuously toward the said control electrode direction from the said 1st guide.

Preferably, the second guide is characterized in that formed on the eyelet welded to the cathode located on the outer portion of the R, G, B cathode.

In this way, the heat at the R and B cathodes located at the outer part is stored without being radiated to the outside, so that the actual temperature is almost the same at the three cathodes, so that the distance between each cathode and the control electrode is almost the same. Therefore, the current amount of the R, G, and B beams is almost the same, thereby improving white balance characteristics, and providing a reliable image with almost no luminance difference during initial operation.

And, there may be a plurality of embodiments of the present invention, hereinafter will be described in detail with respect to the most preferred embodiment.

This preferred embodiment allows for a better understanding of the objects, features and advantages of the present invention.

In addition, in drawing used for description, about the component same as FIG. 1-5, the same code | symbol is attached | subjected, and the overlapping description may be abbreviate | omitted.

The cathode for the cathode ray tube according to the present embodiment is formed at the tip of the cylindrical sleeve 8 and one side of the sleeve 8 into which the heater 7 as the heat source is inserted, as shown in FIG. Alkaline earth metal complex containing the main component and a base metal (9) containing trace amounts of activated metals such as magnesium (Mg) and silicon (Si) and a top surface of the base metal (9) and containing at least barium oxide (BaO) It consists of an electrospinning material 10 of oxide and a holder 11 provided outside the sleeve 8 to support the sleeve 8.

In addition, as shown in FIG. 7, the eyelet 12 having the flange 12a formed at the upper end thereof to block radiant heat to the control electrode 2 is welded to a predetermined portion of the holder 11 to support the entire cathode 1. The eyelets 12 welded to the outer R cathode 1R and the B cathode 1B of the three R, G, and B eyelets are used to store heat transferred from the heater 7 to the cathode 1. The guide 12b protrudes continuously toward the control electrode 2 along the edge of the flange 12a.

In the cathode 1 according to the related art configured as described above, when the power is applied to the heater 7 from a stem pin, not shown in the drawing, the heat is generated, the base metal 9 of the cathode 1 is heated by this heat. The electrons are radiated from the electron radiating material 10. The electron beams are controlled, accelerated and focused as they pass through the electrodes 2 to 5 of the electron gun to strike the fluorescent film. Will be.

At this time, the heat radiated from the heater 7 to the sleeve 8 of the cathode 1 is mostly conducted in the direction of the electrospinning material 10 for hot electron radiation, but a part of the heat is the sleeve 8 or the holder 11. It is conducted from the surface of the eyelet 12 or is dissipated by radiation.

The heat dissipation phenomenon of the cathode 1 is large in the R cathode 1R and B cathode 1B positioned at the outer portion of the inline electron gun, and the temperature of these cathodes 1R, 1B is G cathode ( It is lower than the temperature of 1G), and the electrical characteristics vary as the amount of expansion of the control electrode direction of the R cathode 1R and B cathode 1B becomes smaller than the amount of expansion of the control electrode direction of the G cathode 1G. As mentioned above.

However, the temperature difference occurs between the cathode 1G in the center and the cathode 1R and 1B in the outer part, whereas the cathodes 1R and 1B in the outer part exhibit heat dissipation due to conduction and radiation. Since the negative electrode 1G is blocked by the other negative electrodes 1R and 1B, heat is prevented from being dissipated, and thus the same temperature of each of the negative electrodes 1R, 1G and 1B is realized. There may be a method of preventing heat from dissipating heat of the cathodes 1R and 1B located at the outer portion, or a method of improving heat radiation characteristics of the cathode 1G located at the center portion.

The present invention employs the former of the above-described methods, and stores the heat of the R cathode 1R and the B cathode 1B located at the outer portion to substantially equal the temperature at each cathode 1R (1G) 1B. It is intended to be implemented.

To this end, in the present invention, the eyelets 12 welded to the R cathode 1R and the B cathode 1B of the outer portion of the eyelets 12 welded to the respective cathodes 1R, 1G, and 1B are shown in FIG. 7. A guide 12b for heat storage was formed.

At this time, the guide 12b may be formed at both ends of the eyelet 12 for thermal storage of the negative electrode 1, and the electrons of the negative electrode 1 are considered when the thermal expansion characteristic of the negative electrode 1 and the floating force of heat are taken into consideration. It is most effective to form around the radiating material 10.

Therefore, the guide 12b is continuously formed to protrude toward the control electrode 2 along the edge of the flange 12a on the eyelet 12 welded to the R cathode 1R and the B cathode 1B of the outer portion. It is.

As such, when the guide 12b is formed in the eyelet 12 applied to the outer cathodes 1R and 1B, heat is generated from the R cathode 1R and the B cathode 1B of the initial operation outer portion. When dissipated by conduction or radiation to), the guide 12b serves to trap heat, thereby maintaining the temperature of the cathode 1 at a constant level. On the other hand, since the guide 12b is not formed in the eyelet 12 applied to the G cathode 1G in the center, heat may be dissipated by conduction or radiation to the eyelet 12, but the G cathode 1G is located in position. Therefore, since it is in the state blocked by R cathode 1R and B anode 1B, it can be said that heat is stored without guide 12b.

In this case, if the height of the guide 12b applied to the eyelet 12 of the outer part is designed in an appropriate range, the temperature of each of the R, G, and B cathodes 1R, 1G, and 1B can be equally implemented.

Implementing the same temperature of each of the R, G, and B cathodes 1R, 1G, and 1B as described above causes excessive heat to be generated at the initial stage of operation, so that the cathodes are expanded when the cathode 1 is expanded toward the control electrode 2. The thermal expansion amounts of (1R) (1G) and (1B) become the same, and accordingly, as shown in FIG. 8, the intervals Dr '(Dg') between the respective cathodes 1R (1G) 1B and the control electrode 2 ( Db ') is the same, so that the cutoff voltages of the R, G, and B cathodes 1R, 1G, and 1B are the same, as well as the cathode currents of the R, G, and B beams can be radiated the same. It can be said that it has a current characteristic, and as a result, the white balance characteristic can be improved.

9 is a graph showing the rate of change of cathode current of each cathode according to the present invention. As shown, cathode currents of R, G, and B beams are radiated excessively almost equally and then stabilized as time passes. As such, when there is almost no cathode current difference between the R, G, and B beams, the luminance variation of the screen may be small during initial operation, thereby providing a reliable cathode ray tube to the user.

In addition, although specific embodiments of the present invention have been described and illustrated above, it is obvious that the present invention may be variously modified and implemented by those skilled in the art.

Such modified embodiments should not be individually understood from the technical spirit or the prospect of the present invention, and such modified embodiments should fall within the appended claims of the present invention.

It is clear from the above description that, according to the present invention, the thermal expansion amount of each cathode during the initial operation can be equally realized by forming a thermal storage guide in the eyelet applied to the R cathode and the B cathode of the outer part of the in-line electron gun. In addition, the present invention has the effect of providing a reliable cathode ray tube with almost no luminance change.

Claims (2)

In the in-line electron gun in which the cathodes of R, G, and B are arranged side by side in a state welded to the eyelets, and a control electrode for controlling the amount of electron beams is positioned on the cathode: The eyelet is, (1) a first guide bent outward along the circumferential direction at the upper end; And (2) The electron gun structure for a cathode ray tube, characterized in that it comprises a second guide which is continuously protruded from the first guide toward the control electrode direction. The method of claim 1, The second guide is an electron gun structure for a cathode ray tube, characterized in that formed in the eyelet welded to the cathodes located in the outer portion of the R, G, B cathodes.