KR100244230B1 - Structure for electron emission of cathode ray tube - Google Patents

Abstract

The present invention relates to reducing evaporation of barium carbonate in a cathode ray tube cathode structure, preventing the deterioration of emission, increasing the service life, and increasing the resolution of the screen by uniform emission of electrons. A base metal (1) containing a trace amount of an active metal is provided on the upper portion of the cylindrical sleeve (2) in which the cathode heating heater (4) is inserted, and at least the barium oxide (BaO) is sequentially included on the top surface of the base metal (1). A first layer 5 formed of sputtered deposition of the alkaline earth metal composite oxide, and a second layer 6 formed of sputter deposition of osmium-ruthenium (Os-Ru) or iridium (Ir). The present invention relates to a cathode structure for a cathode ray tube.

Description

Cathode Structure for Cathode Ray Tube

The present invention relates to a cathode structure for a cathode ray tube, and particularly to a cathode structure suitable for increasing the resolution of the screen by uniform emission of electrons while increasing the service life by preventing evaporation of barium carbonate and preventing emission degradation. It is about.

Recently, cathode ray tubes require a cathode for cathode ray tube of high current density due to screen size, high definition, and multimedia according to various information.

1 is a schematic cross-sectional view showing a cathode structure for a conventional cathode ray tube, containing a small amount of magnesium (Mg), silicon (Si) and the like on the upper portion of the cylindrical sleeve (2) in which the cathode heating heater (4) is inserted; ) Is provided by forming a base metal (1) as a main component, the electron-emitting material (3) containing at least barium oxide (BaO) on the upper surface of the base metal (1) by a spray coating method.

In the operation according to the above structure, a chemical is formed between the electron-emitting material 3 whose main component is barium oxide (BaO) by the heating of the heater 4 inserted into the sleeve 2 and the activated metal in the base metal 1. The reaction occurs, which results in the generation of free barium (Ba) and electrons from the free barium (Ba).

This causes a continuous chemical reaction during the operation of the cathode ray tube, and the activated metal in the gas metal (1) diffuses in the gas metal (1) to move to the surface of the gas metal (1) and to chemically react with the electron radiating material (3). Will be.

Looking at the reaction scheme as a chemical symbol is as follows.

Cathode current density refers to the maximum possible current density when the end point of the lifetime is defined as about 20,000 hours when the maximum current of the cathode reaches 40 to 50% in the cathode ray tube. The current density can be up to about 2 A / cm 2.

However, the if the anode current density at a cathode structure used for more than 2A / ㎠ becomes the source of the electron generating free barium (Ba) this requires a lot more, whereby a high-resistance material, as in the above chemical reaction formula Ba ₂ SiO ₄ As a large amount of and MgO is generated, high heat is generated to deteriorate the operating life.

In addition, the conventional method of manufacturing the negative electrode adopts the spray coating method, and the porosity is 60%, so the carbonate evaporation of the negative electrode is large, the emission (Emission) characteristics deteriorate.

Meanwhile, there is a method of preparing barium oxide, strontium oxide and calcium oxide to form an electron-emitting material layer on a metal substrate through a sputtering process (Korean Patent Publication No. 97-23606).

However, since such a cathode has a high work function, Tk (cathode temperature) is high, and barium carbonate is evaporated to increase the emission (Emission) degradation.

The present invention has been made in order to solve the above-mentioned conventional problems, there is little porosity of the negative electrode, the work function can be lowered, it is possible to lower the temperature of the cathode, deterioration of the emission (Emission) by suppressing evaporation of barium carbonate The purpose of the present invention is to obtain a cathode structure capable of high current density and long life by preventing the damage.

1 is a schematic cross-sectional view showing a cathode structure of a conventional cathode ray tube

Figure 2 is a schematic cross-sectional view showing the cathode structure of the cathode ray tube of the present invention

Explanation of symbols for main parts of the drawings

1: Gas metal 2: Sleeve

4: heater 5: first floor

6: 2nd layer 7: Electron emission material layer

The present invention for achieving the above object is provided with a base metal containing a trace amount of the active metal on the top of the cylindrical sleeve is inserted into the heater for heating the cathode, the alkaline earth metal complex oxide containing barium oxide (BaO) on the gas metal upper surface And a cathode structure having a first layer formed by sputtering deposition and a second layer formed by sputter deposition of osmium-ruthenium (Os-Ru) or iridium (Ir) on the first layer.

It is preferable that the thickness of the said 1st layer shall be 1 micrometer or more.

Figure 2 is a cross-sectional view of the negative electrode structure according to the present invention, containing a small amount of activated metal such as magnesium (Mg), silicon (Si) on the top of the cylindrical sleeve (2) in which the heater (4) for the negative electrode heating is inserted An alkaline earth metal composite oxide including at least barium oxide (BaO) is formed on the first layer 5 on the upper surface of the base metal 1 by sputter deposition, and the second layer 6 is provided with a base metal 1. Os-Ru or Ir consists of an electron-emitting material layer 7 formed by sputter deposition.

The sputtering method utilizes a phenomenon in which a metal particle scatters and adheres to a nearby object surface when a metal is heated or an ion shock is applied to the metal in a chamber of low pressure.

Sputtering of Os-Ru or Ir because the cathode surface is not hard when the first layer 5 of the alkaline earth metal composite oxide containing barium oxide (BaO) is made by the conventional spray coating method. Although the deposition is impossible, the present invention is because the sputtering of the first layer (5) becomes dense and the surface becomes hard, so that sputtering deposition of Os-Ru or Ir on the upper layer, that is, the second layer (6) This makes it possible to obtain a cathode structure capable of high current and long life.

The present invention looks at the operation structure of the electron generation in the cathode ray tube of the cathode structure for cathode ray tube of the alkaline earth metal composite oxide containing at least barium oxide (BaO) by the heating of the heater (4) inserted into the cathode sleeve (2) A chemical reaction occurs between the electron-emitting material and the activated metal or alkaline earth metal in the gas metal (1), thereby generating free barium (Ba) and generating electrons from the free barium (Ba).

This causes a continuous chemical reaction during the operation of the cathode ray tube, and the activated metal in the gas metal (1) diffuses in the gas metal (1) to move to the surface of the gas metal (1) and to chemically react with the electron radiating material (7). Will be.

For example, if the strontium (Sr) is contained as the alkaline earth metal in the base metal (1), the reaction formula is as follows.

The present invention provides a free atom of the alkaline earth metal, which is the source of electron generation, from the alkaline earth metal except for magnesium (Mg) in the base metal (1) during the service life. When used at about 2 A / cm 2 or more, a thin film is formed on the first layer 5 of the upper surface of the base metal 1 by sputtering deposition of an alkali earth metal composite oxide containing at least barium oxide (BaO), and the second layer 6 ) Is sputtered and deposited to form a thin film of Os-Ru or Ir, which is a rare earth metal, thereby reducing the evaporation of barium carbonate and improving the emission due to almost no porosity of the cathode.

In addition, Os-Ru or Ir is a material that can lower the work function. It is possible to lower the Tk (cathode temperature), which reduces the evaporation of barium carbonate, thereby reducing the deterioration of emission. Long life cathode structure.

By forming a thin film by sputtering deposition of Os-Ru and Ir on the second layer (upper), since the cathode has a very fine and uniform layer of electron-emitting material, electrons emitted are uniform, thereby increasing the screen resolution.

As described above, the present invention provides a first layer 5 made of an alkaline earth metal complex oxide containing at least barium oxide (BaO) on the upper surface of the base metal 1 and a second layer made of Os-Ru or Ir, respectively. By depositing by the sputtering method, the cathode has almost no porosity and the work function can be lowered. Thus, deterioration of emission is prevented by suppressing evaporation of barium carbonate, thereby obtaining a cathode structure having the effect of high current density and long life.

Claims (3)

A base metal (1) containing a trace amount of an active metal is provided on the upper portion of the cylindrical sleeve (2) in which the cathode heating heater (4) is inserted, and at least the barium oxide (BaO) is sequentially included on the top surface of the base metal (1). A cathode structure for a cathode ray tube, characterized in that it comprises a first layer (5) on which an alkaline earth metal composite oxide is formed, and a second layer (6) on which osmium-ruthenium (Os-Ru) or iridium (Ir) is formed. The method of claim 1, Cathode structure for cathode ray tube, characterized in that the thickness of the first layer (5) is 1㎛ or more. The method of claim 1, A cathode structure for a cathode ray tube, characterized in that the second layer is formed by sputtering deposition of osmium-ruthenium (Os-Ru) or iridium (Ir).

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