KR20010054764A - Structures and manufacture methode for cathode of electron gun in Cathode Ray Tube - Google Patents

Abstract

PURPOSE: An electrode structure of an electron gun for a CRT and a fabricating method of the same are provided to be capable of increasing a brightness point cancel voltage by forming first/second grid electrodes into a capacitor electrode to increase the voltage difference between the two grid electrodes, decreasing the gap between the electrodes and decreasing the thickness of the first grid electrode. CONSTITUTION: A dielectric thin film layer(113) and a first grid electrode thin film layer(114) are sequentially formed under a second grid electrode(112) so that the first/second grid electrodes have a capacitor structure. Three electron beam passage holes(115) are asymmetrically formed interior of the second electrode(112), the dielectric thin film layer(113) and the first grid electrode thin film layer(114). Preferably, the dielectric thin film layer(113) consists of BaTiO3.

Description

Electrode structure of electron gun for cathode ray tube and its manufacturing method {Structures and manufacture methode for cathode of electron gun in Cathode Ray Tube}

In particular, the electrode structure for the cathode ray tube according to the present invention and the manufacturing method thereof have a capacitor structure of the first grid electrode and the second grid electrode, thereby increasing the bright spot voltage and improving the high current density of the double cathode and the resolution of the image. The present invention relates to a cathode ray tube electrode structure and a method of manufacturing the same.

A schematic diagram of a conventional cathode ray tube electron gun is shown in Figure 1,

A three-pole portion comprising a cathode 101 which directly emits hot electrons by the heating of the heater, and a first grid electrode 102 and a second grid electrode 103 for controlling the electron beam; The main lens unit is composed of the third, fourth, fifth and sixth grid electrodes 104, 105, 106 and 107.

A shield cup 108 is formed on the left side of the sixth grid electrode 107 to shield and weaken the leakage magnetic field of the deflection yoke. It is disposed along the axis of the electron gun 100 at predetermined intervals, and is buried in a pair of bead glass 109 which is a rod-shaped electrical insulator.

Three electron beam through holes are formed in the first grid electrode 102 to the sixth grid electrode 107 in a direction XX which is asymmetric with respect to the traveling direction ZZ direction of the electron beam, respectively. It is formed on the same plane of the electrode.

On the other hand, Figure 2 is a partial cross-sectional view of the oxide cathode, looking at its configuration,

Emission layer 101a for emitting hot electrons to electron beam passing holes 110 of the first and second grid electrodes 102 and 103, and the electron radiating material 101a and supporting heat Gap-type base metal (101b), conduction to help the reduction of hot electrons, a heater (101c) for generating heat, and heat generated from the heater (101c) the upper gas metal ( A sleeve 101d that conducts to 101b).

Referring to the accompanying drawings, the electrode structure of a conventional cathode ray tube electron gun configured as described above is as follows. 1 is a longitudinal cross-sectional view showing a part of the conventional electron gun for the cathode ray tube, and FIG. 2 is a partial cross-sectional view showing the first and second grid electrodes and the cathode structure for the conventional cathode ray tube.

First, referring to FIG. 1, in the electron gun 100, hot electrons are emitted by heat generated by a heater (101c of FIG. 2) inserted into the cathode 101, and the emitted hot electrons are discharged to the first grid electrode 102. The amount of the electron beam is controlled by the second grid electrode 103 and has an acceleration property. The cathode 101, the first and second grid electrodes 102 and 103 are called triodes. do.

As the cathode 101 is heated and hot electrons are emitted, the electron beam is attracted and controlled by the first grid electrode 102 and accelerated by the second grid electrode 102 to form a third to sixth grid, which is the main lens system. The light is concentrated and accelerated by the difference in voltage applied to the electrodes 104, 105, 106, and 107, and then emits the phosphor coated on the inner surface of the panel (not shown), thereby forming an image on the screen.

To this end, the cathode 101 for the cathode ray tube that emits hot electrons is generally an impregnated cathode or an oxide cathode using hot electron emission characteristics. The impregnated cathode has a high current density, but the manufacturing cost is very high compared to the oxide cathode, there is a limit to the application, the oxide cathode is easy to manufacture, but does not yet have a high current density is under development to have a high current density.

As shown in FIG. 2, when the rated voltage (approximately 6.3 V) is applied to the heater 101d, the oxide cathode generates heat of a required amount of heat in the heater 101d within 2 to 3 seconds. It is conducted to the base metal 101b through the sleeve 101c or directly to the base metal 101b, and then to the electron-emitting material 101a, thereby inducing electron radiation of the required density.

To this end, the electron-emitting material 101a is thermally decomposed into oxides by activation heat treatment at high temperature and stabilized by an aging heat treatment applying a voltage. At this time, the oxides are reduced by the reducing agent in the base metal 101b to free barium as a source of hot electrons. Oxygen vacancy is formed by the formation of (Free Ba), and two hot electrons are generated for one oxygen vacancy.

In addition, the hot electrons generated from the free barium are released into the vacuum by overcoming the surface work function of the electron-emitting material 101a, and the emitted hot electrons have a certain emission angle with some energy at the surface of the cathode 101. Is released.

The hot electrons emitted in this way are accelerated by the beam forming region formed by the series of first and second grid electrodes 102 and 103 disposed on the front surface of the cathode.

To this end, the first grid electrode 102 and the second grid electrode 103 is formed with an electron beam through hole 110 through which hot electrons can be accelerated to form an aperture lens to accelerate the electron beam.

The first grid electrode 102 is positioned between the electron-emitting material 101a of the cathode 101 and the second grid electrode 103 to reduce the size of the object of the electron beam obtained from the surface of the cathode and reduce the number of MHz. It is provided to enable electron beam current modulation during the time variation of the frequency of the frequency (period of several kHz).

In addition, the first grid electrode 102 is grounded (GND) and the voltage of the cathode 101 is smaller than the second grid electrode 103 in the process of forming the electron beam by the release of hot electrons from the surface of the actual cathode. Is applied to modulate the current of the electron beam.

That is, the voltage Ec1 of the first grid electrode 102 is a negative potential compared to the voltage Ek applied to the cathode 101, and the zero equipotential line is the first and the second. It exists at any position (almost along the surface of the first grid electrode) between the two grid electrodes 102 and 103, and is bent toward the cathode surface toward the cathode center axis to cross the cathode surface with a hot electron emission radius (r in FIG. 4). do.

The hot electron emission radius r on the surface of the cathode is proportional to the pore diameter D1 of the first grid electrode 102. The hot electron emission radius r influences the area of the surface from which hot electrons are emitted. r ² ), and the effective emission area finally determines the resolution of the image.

In general, the geometrical relationship between the cathode 101 and the first and second grid electrodes 102 and 103 plays a very important role in the thermal electron emission characteristics of the cathode 101 and the resolution of the image. The factor is the Ekco-Cathode cutoff voltage, which is shown in Equation 1.

Ekco ∝ (Dl) ³ × Ec2 / d1 × d2 × t

Where D1 is the pore diameter of the first grid electrode, Ec2 is the voltage difference between the first and second grid electrodes (= Ec2-Ec1; Ecl = 0), d1 is the gap between the cathode and the first grid electrode, and d2 is the first The interval between the first grid electrode and the second grid electrode, t is the thickness of the first grid electrode.

The hot electron emission current i is proportional to the bright point erase voltage Ekco. In other words, as the brightening voltage increases, the hot electron emission current of the negative electrode increases and more hot electrons can be forcibly drawn from the negative electrode surface.

However, as described above, if the cathode 101 has high current density characteristics, the bright point elimination voltage Ekco may be lowered. When the bright point voltage is lowered, the pore diameter D1 of the first grid electrode 102 may be reduced. Although it is possible to increase the resolution of an image, it is very difficult to realize high current density characteristics only by the cathode itself.

To this end, one method is to reduce the pore diameter D1 of the first grid electrode 102 more than the conventional procedure (˜0.37 mm), which is very difficult. This is because at the current density level of the conventional cathode 101, the bright point erase voltage cannot be lowered to exert a certain amount of hot electron emission current i.

Alternatively, the distance between the cathode 101 and the first grid electrode 102 should be reduced to be much smaller than the conventional level (~ 0.1 mm), which is difficult to manufacture by controlling the gap conventionally. When the distance d1 between the 101 and the first grid electrode 102 is reduced, many problems such as thermal defects on the cathode are caused.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems, and has a first grid electrode and a second grid electrode as a capacitor structure in order to increase the high current density characteristics of the cathode and the resolution of an image, and thus the first and second grid electrodes. It is an object of the present invention to provide an electrode structure for a cathode ray tube and a method of manufacturing the same, in which a voltage difference between them is small and the thickness of the first grid electrode is made thin to increase the bright point erase voltage.

1 is a longitudinal cross-sectional view showing a part of the conventional electron gun for the cathode ray tube.

2 is a partial cross-sectional view showing a first and second grid electrode and a cathode structure of a conventional cathode ray tube electron gun.

3 is a partial cross-sectional view showing an electrode structure of an electron gun for a cathode ray tube electron gun according to the present invention, the first and second grid electrodes, the cathode structure;

4 is a view showing the current density of hot electrons emitted from the surface of the cathode according to the present invention.

5 is a view for showing an electrode manufacturing method of the electron gun for the cathode ray tube for the present invention.

Figure 6 is a bright spot voltage, hot electron emission radius, the current density distribution of hot electrons in accordance with an embodiment of the present invention.

<Description of Symbols for Major Parts of Drawings>

100 ... electron gun 101,111 ... cathode

102 First grid electrode 103,112 Second grid electrode

104 ... third grid electrode 105 ... fourth grid electrode

106 ... Fifth Grid Electrode 107 ... Fifth Grid Electrode

108 ... Shield Cup 109 ... Beadglass

110,115 Electron beam passing through 113 Dielectric thin film layer

114 ... first grid electrode thin film layer 101a, 111a ... electron-emitting material

101b, 111b ... gas metal 101c, 111c ... heater

101d, 111d ... sleeve

In the cathode ray tube electrode structure according to the present invention for achieving the above object, in the cathode ray tube electron gun electrode for controlling and accelerating the electron beam formed by the hot electrons emitted from the cathode,

Forming a dielectric thin film layer on the bottom of the second grid electrode such that the first grid electrode and the second grid electrode positioned on the cathode are formed in a capacitor structure, and forming a first grid electrode thin film layer on the bottom of the dielectric thin film layer. It is characterized by.

To this end, the dielectric thin film layer formed on the first grid electrode according to the present invention is characterized by using a barium titanate dielectric material, the first grid electrode thin film layer is characterized by using a platinum electrode material.

The thickness of the dielectric thin film layer according to the present invention is about 5 times larger than the thickness of the first grid electrode thin film layer, and the thickness of the dielectric thin film layer and the first grid electrode thin film layer is set within the range of about 5 ~ 50㎛. .

The potential of the second grid electrode, the dielectric thin film layer, and the first grid electrode thin film layer according to the present invention is that the second grid electrode has a positive potential, the dielectric thin film layer has a negative potential with respect to the second grid electrode, and the second grid electrode. The thin film layer is characterized in that it is charged at a negative potential with respect to the dielectric thin film layer.

The electron gun electrode manufacturing method for a cathode ray tube according to the present invention,

Coating a dielectric material on the bottom of the second grid electrode spaced apart from the top of the cathode to control the electron beam by a spin coating method to form a thin film layer of the dielectric material;

And coating platinum on the bottom of the coated dielectric thin film layer by a sputtering coating method to a thickness of about 10 μm to form the first grid electrode thin film layer close to the cathode.

Hereinafter, with reference to the accompanying drawings as follows. 3 is a partial cross-sectional view showing an electron gun first and second grid electrodes and a cathode structure as an embodiment of an electron gun electrode structure for a cathode ray tube, and FIG. 4 is a view showing a current density of hot electrons emitted from a surface of a cathode of the present invention and the conventional art. FIG. 5 is a schematic view illustrating the fabrication of an electron gun electrode structure for a cathode ray tube, and FIG. 6 is a view illustrating a comparison of a spot voltage, a hot electron emission radius, and a current density distribution of hot electrons according to an embodiment of the present invention.

First, in a cathode ray tube electron gun electrode having a cathode 111 for emitting hot electrons, a first grid electrode for modulating an electron beam, and a second grid electrode 112 for accelerating an electron beam,

A dielectric thin film layer 113 is formed on the bottom of the second grid electrode 112 so that the second grid electrode and the first grid electrode have a capacitor structure, and a first grid electrode is formed on the bottom of the dielectric thin film layer 112. The thin film layer 114 is formed.

Reference numeral 111a denotes an electrospinning material, 111b denotes a base metal, 111c denotes a heater, and 111d denotes a sleeve.

With reference to the accompanying drawings for the present invention configured as described above will be described with reference to the same parts as the conventional description is omitted.

First, referring to FIG. 3, a dielectric thin film layer is formed on the bottom surface of the second grid electrode 112, and the first grid electrode thin film layer 114 is spaced apart from the cathode 111 on the bottom surface of the dielectric thin film layer 113. Is formed. In other words, the first and second grid electrodes have a capacitor structure.

Here, three electron beam passing holes 115 through which the electron beam can pass are formed in the asymmetric axis in the second grid electrode 112, the dielectric thin film layer 113, and the first grid electrode thin film layer 114.

In this structure, when a positive voltage is applied to the second grid electrode 112, the potential of the dielectric thin film layer 113 is charged to a negative potential in the direction toward the second grid electrode 112. Charging or electrification) and charging at a positive potential in the opposite direction (the first grid electrode side).

The potential of the first grid electrode thin film layer 114 opposite the second grid electrode 112 to the bottom of the dielectric thin film layer 113 becomes a negative potential with respect to the dielectric thin film layer 113.

This action causes the second grid electrode 112 and the first grid electrode thin film layer to have a negative potential opposed to the positive potential applied to the second grid electrode 112 to be formed on the first grid electrode thin film layer 114. The voltage difference between 114 becomes relatively large.

More specifically, the voltage applied to the first grid electrode thin film layer 114 by the capacitor structure (Ec1 in FIG. 2) is equal to the negative potential Ec2 = equal to the voltage Ec2 of the second grid electrode 112. -Ec1), the potential applied to the first grid electrode thin film layer 114 has a much larger negative potential than the conventional (GND in FIG. 2).

Due to the capacitor structure, the thickness t2 of the first grid electrode thin film layer 114 can be made thin, and the distance d3 between the first grid electrode and the second grid electrode can be made very narrow, and thus the existing cathode and the first Even if the gap d1 between the grid electrodes and the pore diameter D1 of the first grid electrode are the same as before, the bright point elimination pressure Ekco due to the capacitor structure is significantly increased.

In addition, the current density of the hot electrons emitted from the surface of the cathode 111 is as shown in Figure 4, the maximum current density (Jo, Peak Current Density) of the hot electrons emitted from the surface center of the cathode effective emission area is hot electron emission It is related to the current (i) and the hot electron emission radius (ro), which is Jo = 5/2 × i / It looks like r ² .

Accordingly, the maximum current density Jo at the center of the surface of the cathode 111 is inversely proportional to the hot electron emission radius ro, and the maximum current density Jo increases as the hot electron emission radius decreases at a constant hot electron emission current i. do. That is, it can be seen that the maximum current density (Jo) is increased and the hot electron emission radius (ro) is also decreased at the center of the cathode surface of the present invention compared to the conventional cathode.

On the other hand, Figure 5 is a view for showing the manufacturing method of the capacitor electrode structure described above.

First, a barium titanate (BaTiO ₃ ) dielectric material is uniformly coated on the bottom surface of the second grid electrode 112 to a thickness d3 of about 50 μm by spin coating to form the dielectric thin film layer 112.

Platinum (Pt) is uniformly coated on the bottom surface of the coated dielectric thin film layer 113 by a sputtering coating method at a thickness t2 of about 10 μm to form a first grid electrode thin film layer 114.

As described above, the dielectric thin film layer 113 formed on the bottom surface of the second grid electrode 112 is coated five times thicker than the thickness of the first grid electrode thin film layer 114 to form a capacitor structure.

6 is a table of the results according to the conventional and embodiments of the present invention,

Conventionally, the electron beam passing hole D1 of the first grid electrode is about 0.37 mm,

The voltage difference Ec2 between the first and second grid electrodes is about 300V,

The distance d1 between the cathode and the first grid electrode is about 80 μm,

The distance d2 between the first grid electrode and the second grid electrode is about 160 μm,

The hot electron emission current (i) is about 0.3 mA,

The thickness t1 of the first grid electrode is about 100 μm, the bright point elimination voltage Ekco is about 50 V, the maximum current density Jo is about 1.0 A / cm ² , and the hot electron emission radius ro is about 103 μm. (See FIG. 2).

In contrast, the present inventions 1 and 2 show that the thickness d3 of the dielectric thin film layer is about 50 μm and the thickness t2 of the first grid electrode thin film layer is about 10 μm.

Brightening voltage (Ekco) is about 80V, 105V,

Maximum current density (Jo) is about 1.5 A / cm ² , 1,9 A / cm ² ,

And the hot electron emission radius (ro) is about 83㎛, 74㎛ respectively.

In the present invention 3, the thickness d3 of the dielectric thin film layer is about 50 μm, and the thickness t2 of the first grid electrode thin film layer is about 10 μm.

Brightening point erase voltage (Ekco) is about 150V

Maximum current density (Jo) is about 2.6 A / cm ² ,

And the hot electron emission radius (r) is about 64㎛.

Here, comparing the present invention 3 with the conventional results, the bright point voltage (Ekco) was increased by about 300%, the maximum current density (Jo) was increased by 260%, and the hot electron emission radius (ro) was reduced by about 40%. Able to know.

In addition, in the present invention 4, the maximum current density (Jo) of the cathode that can be used is about 7.32 A / cm when the above results (Invention 1 to 3) are used and the hot electron emission radius (ro) is maintained at the same level as before. ² is about 730% more than conventional.

Therefore, such a rapid increase in the point erase voltage Ekco maximizes the hot electron emission of the cathode, thereby increasing the high current density of the cathode and the resolution of the image.

As described above, the present invention forms a dielectric thin film layer and a first grid electrode on the bottom of the second grid electrode in the direction of the cathode to have a capacitor structure, thereby improving the point-breaking point pressure and the current density of the cathode by several hundred percent. In addition to zooming, the hot electron emission radius is reduced by several ten percent compared with the prior art, which reduces the radius of the electron beam reaching the image, resulting in an increase in the resolution of the image.

In addition, there is an effect of solving the problems in the improvement of the bright spot erase voltage, and double the conventional gap between the cathode and the first grid electrode and the mass production of the electron beam through hole of the first grid electrode.

In addition, since the voltage of the first grid electrode thin film layer is controlled by the capacitor structure according to the voltage applied to the second grid electrode, there is no need to perform a separate voltage control on the first grid electrode thin film layer.

Claims (7)

An electron gun electrode for a cathode ray tube for controlling and accelerating an electron beam formed by hot electrons emitted from a cathode, Forming a dielectric thin film layer on the bottom of the second grid electrode such that the first grid electrode and the second grid electrode positioned on the cathode are formed in a capacitor structure, and forming a first grid electrode thin film layer on the bottom of the dielectric thin film layer. An electrode structure of an electron gun for cathode ray tubes. The method of claim 1, The dielectric thin film layer formed on the bottom of the second grid electrode is an electrode structure of the electron gun for cathode ray tube, characterized in that using a barium titanate dielectric material. The method of claim 1, The first grid electrode thin film layer formed on the bottom surface of the dielectric thin film layer, the electrode structure of the electron gun for cathode ray tube, characterized in that using a platinum electrode material. The method of claim 1, The thickness of the dielectric thin film layer is an electrode structure of the electron gun for cathode ray tube, characterized in that to form about five times larger than the thickness of the first grid electrode thin film layer. The method according to claim 1 or 4, The electrode structure of the electron gun for cathode ray tube, characterized in that the thickness of the dielectric thin film layer and the first grid electrode thin film layer is set within the range of 5 ~ 50㎛. The method of claim 1, The potentials of the second grid electrode, the dielectric thin film layer, and the first grid electrode thin film layer are positive potentials of the second grid electrode, the dielectric thin film layer is negative potential with respect to the second grid electrode, and the second grid electrode thin film layer is the dielectric thin film layer. Electrode structure of an electron gun for a cathode ray tube, characterized in that it is charged with a negative potential in proportion to the thickness of. Forming a thin film layer of the dielectric by coating a dielectric material on the bottom surface of the second grid electrode spaced from the top of the cathode to control the electron beam by a thickness of about 50 μm by spin coating; Electroplating of the cathode ray tube electron gun comprising the step of forming a first grid electrode thin film layer in close proximity to the cathode by coating the platinum on the bottom surface of the dielectric thin film layer in the step by a sputtering coating method to a thickness of about 10㎛ Way.