KR100726838B1 - electron gun and the fabrication method thereof for the cathode ray tube with cold cathode - Google Patents

Abstract

The present invention relates to an electron gun for a cathode ray tube employing a cold cathode, and a method for manufacturing the same. In the conventional electron gun, there is a problem in that the resolution of the screen is reduced due to the extreme aberration caused by the center mismatch between the cold cathode and the electron beam passing hole of the electrode. Therefore, in the present invention, when manufacturing an electron gun for a cathode ray tube employing a cold cathode, the process of finally attaching a cold cathode having a larger area than a desired electron beam radiation region to the cold cathode support to combine the electron gun, and excluding a predetermined electron beam radiation region By applying the electron radiation suppressing material to the remaining areas of the cold cathode, the electron radiation suppression cold cathode portion of the predetermined region in which the cold cathode provided in the electron gun radiates the electron beam, and the electron radiation suppression in the region excluding the electron beam radiation cold cathode portion It is characterized in that the material is made to be made of an electron beam radiation suppression cold cathode portion is suppressed radiation of the electron beam.

According to the present invention, it is not influenced by the accumulated assembly error in the process of mounting the cold cathode in the electron gun, but only depends on the assembly error between the mask and the electron gun electrodes and the positioning hole of the mask and the position error of the mask. The overall position error can be limited to within ± 0.02 mm, thereby improving the focus characteristic of the electron beam formed on the screen, thereby improving the resolution on the screen.

Description

Electron gun for cathode ray tube employing cold cathode and its manufacturing method {electron gun and the fabrication method according for example cathode ray tube with cold cathode}             

1 is a cross-sectional view of a general color water tube.

2 is a cross-sectional view showing the configuration of an electron gun of a color receiver.

3 is a cross-sectional view of one cold cathode tip;

4 is a plan view of a cold cathode having a gate;

5 is a configuration diagram of a cold cathode support on which a cold cathode is mounted.

6 is a shape diagram of an electrode of an electron gun adjacent to a cold cathode support;

7 is a process chart for depositing an electron emission suppressing material after aligning the center of the electron beam through hole of the cold cathode according to the present invention.

8 is a shape diagram of a horizontal keyhole and a vertical keyhole mask electrode according to the present invention;

<Explanation of symbols for main parts of the drawings>

1 panel 2 funnel

3: bulb 4: neck part

5: electron beam 6: electron gun

7: fluorescent film 8: shadow mask                 

9: deflection yoke 10: cathode

11: first electrode 12: second electrode

13: 3rd electrode 14: 4th electrode

15 focus electrode 16 anode electrode

17: shield cup 18: bead glass

20: cold cathode 21: cold cathode emitter

30 cold cathode support 31 positioning hole

40: electrode of electron gun 41: electron beam passing hole

42: positioning hole 50: horizontal keyhole mask

51: drilling part 52: masking part

53: positioning hole 60: vertical keyhole mask

61: drilling part 62: masking part

63: positioning hole 70: guide pipe

The present invention relates to an electron gun for a cathode ray tube employing a cold cathode, and a method for manufacturing the same. Specifically, the electron gun can be matched without focusing precisely the mechanical center of the cold cathode and the electron beam through-hole in the electron gun. The present invention relates to an electron gun for a cathode ray tube employing a cold cathode capable of improving performance, and a method of manufacturing the same.

1 is a cross-sectional view of a general color water tube. Referring to FIG. 1, the color water tube includes a panel 1 and a funnel 2 made of glass, a bulb 3 formed to maintain a vacuum degree of 10 ⁻⁷ Torr, and a neck portion 4 formed on the bulb 3. ), A red, green, and blue tricolor fluorescent film coated on the panel 1 with an electron gun 6 mounted so as to emit an electron beam 5, and electron beams 5 emitted from the electron gun 6, respectively. 7 and a deflection yoke 9 for deflecting the electron beam 5 radiated from the electron gun 6 and positioned outside the funnel 2.

2 shows a side view of a typical CRT electron gun 6. Referring to FIG. 2, the electron gun fluoresces the cathode 10 emitting the hot electrons, the first electrode 11 and the second electrode 12 controlling the hot electrons emitted from the cathode 10, and the electron beam 5. The focus electrode 15, the anode electrode 16, and the shield cup 17 are arranged in a row so as to form a capacitive focusing lens for focusing on the film 7, so that the non-insulated bead glass ( It is fixed by 18).

Although not shown in FIG. 2, the hot electrons emitted from the cathode by the heating of the heater inserted into the cathode are controlled by the first electrode 11 and drawn out by the second electrode 12. 15) and a capacitive lens formed by the anode electrode 16 to focus and form a beam spot on the fluorescent film 7.

On the other hand, in recent years, due to continuous development of flat panel display devices, research into using field emission devices instead of heaters and thermal electron emission cathodes has been conducted in various fields.

In the case of using a thermoelectromagnetic radiation cathode, it takes time to reach about 800 ° C., which is required for thermoelectron radiation, and energy to provide heat. It is possible to operate and does not need a heater and energy to provide heat.

Disadvantages caused by thermal expansion include over-shoots, which show a change in initial electron radiation, and STC-drift, in which the three electron beams coincide on the screen over time due to uneven expansion of the electrodes. .

Such a hot electron emission cathode is called a hot cathode, and a field emission cathode is called a cold cathode.

3 shows a structure of a general field emission cold cathode emitter with a gate structure. As shown in the figure, the field emission cold cathode emitter 21 is applied to a strong electric field using a voltage of 50V to 200V adjacent to the tip having a sharp angle (Molybdenum tip) 21e and within a few μm within a few μm. And a Mo or Cr gate electrode 21a for emitting electrons and a SiO ₂ insulator 21b for supporting and fixing the gate electrode 21a. In the figure, reference numeral 21c denotes a conductive layer and 21d denotes a silicon substrate.

4 shows a plan view of the entire cold cathode 20 in which these cold cathode emitters are collected. The points inside the individual holes in the figure indicate the tip of the tip 21e. Of course, Fig. 4 is shown briefly, and the actual cold cathode has very many tips. The efficiency of the field emission cold cathode is expressed by the Fowler-Nordheim equation, as shown in equation (1).

Where I is the current, V is the applied voltage, and A and B are constants.

The slope of the Fowler-Nordheim equation depends on the shape of the tip, and the sharper the tip, the greater the slope, and therefore the greater the current change to voltage change. In order to obtain a large current at a low driving voltage, a method of lowering the work function of the device or sharpening the shape of the tip is adopted.

The main difference between the electron gun employing the hot cathode and the electron gun employing the field emission cold cathode is the kinetic energy of the electron beam at the cathode and the electron radiation region. Electrons radiated from the hot cathode have their own kinetic energy of only a few eV, so that the movement of the electron beam is constrained by the penetration field of the second electrode passing through the first electrode hole.

Thus, although the size of the hot cathode surface is much larger than the electron beam through holes of the first electrode and the second electrode, the electron beams are emitted only in the portion that is subjected to the output by the penetrating electric field of the second electrode.

Therefore, in the electron gun using the hot cathode, the alignment between the center of the hot cathode and the center of the electron beam passing hole of the electrode of the electron gun is not very important.                         

However, since the cold cathode has a gate electrode, the kinetic energy of the emitted electrons is similar to the potential of the gate electrode. Further, electrons are emitted from the entire cold cathode surface because the extraction of the electron beam is due to the voltage applied to the gate electrode.

Therefore, in the electron gun using the cold cathode, if the center of the cold cathode and the electron gun electrodes do not coincide with each other, the electron beams undergo severe aberration from the triode, so the focus characteristic on the screen is very deteriorated.

Since the coincidence between the centers of the three-pole electrodes required in the electron gun is ± 10-20 탆, the center of the cold cathode and the center of the electron beam through-holes of the electron gun electrodes must also be strictly matched in this manner.

In order to mount a cold cathode in an electron gun, the following procedure is generally carried out.

First, the cold cathode formed on the wafer is cut into a suitable size using a cutter.

Second, each cold cathode 20 cut to a predetermined size is mechanically positioned by using a jig or the like for fixing the position, and then fixed to the cold cathode support 30 by using an adhesive means. 5 shows a shape in which the cold cathode 20 cut out from the wafer is fixed to the cold cathode support 30. Here, reference numeral 20a in a rectangular shape indicates that the cold cathode 20 is more relaxed in order to ease the work when the cold cathode 20 is cut out from the wafer.

Third, using the positioning hole 31 made in the cold cathode support 30 and the positioning hole 42 made in the first electrode 40 of the electron gun, the other electrode of the cold cathode support 30 and the electron gun in manufacturing the electron gun Determine the location between them. Here, reference numeral 41 denotes an electron beam through hole.

The cold cathode support 30 and the other electrodes 40 of the electron gun are combined into one electron gun through a beading process while their positions are determined using the respective positioning holes 31 and 42.

However, as the cold cathode is mounted using different criteria at various stages, it is very difficult to accurately match the center of the cold cathode to the center of the electron gun.

Dimensional error ± 0.05mm due to cutting of the cold cathode wafer and error ± 0.05mm generated when fixing the cold cathode 20 to the cold cathode support 30, the center of the cold cathode 20 and the cold cathode support 30 Since the coupling error of the maximum center reaches ± 0.12mm by the mechanical error ± 0.01mm with the center of the positioning hole 31, the error close to 10 times the tolerance can be generated.

With this positional error, the electron beam emitted from the cold cathode electron gun undergoes extreme aberration from the triode, and the resolution on the screen is very degraded due to the enlarged aberration effect passing through the main lens.

SUMMARY OF THE INVENTION The present invention has been made to solve such a conventional problem, and once the cold cathode is coupled to the electron gun, the cold cathode and electron gun electron beam passing holes generated from the electron gun employing the cold cathode are controlled by adjusting the electron beam radiation area of the cold cathode. An object of the present invention is to provide an electron gun employing a cold cathode capable of effectively suppressing extreme aberration caused by a mismatch of the centers of the same and a method of manufacturing the same.

The electron gun employing the cold cathode according to the present invention has an electron radiation suppressing material in an area excluding an electron beam radiation cold cathode portion having a diameter of 0.3 mm or more, and an electron beam radiation cold cathode portion, centered on an emitter tip through which the cold cathode emits an electron beam. It is characterized by consisting of the cold-cathode portion of the electron beam radiation suppression is applied to suppress the radiation of the electron beam.

In addition, a method of manufacturing an electron gun employing such a cold cathode may include attaching an electron gun by attaching a cold cathode having a larger area than a desired electron beam radiation region to a cold cathode support, and remaining regions of the cold cathode except for the electron beam radiation region. It is characterized by performing a process of applying the electron emission suppressing material to.

When applying the electron emission suppressing material, a mask electrode for depositing the electron emission suppressing material in a region other than the desired electron beam emission region may be used.

When applying the electrospinning suppression material using the mask electrode, first, the process of first applying the electrospinning suppression material through the horizontal keyhole shape mask electrode and the second application of the electrospinning suppression material through the vertical keyhole shape mask electrode. To perform the process.

The cold cathode according to the present invention has a larger electron emission region than the cold cathode of the prior art. The cold cathode and the electron gun may be combined with each other using a conventional technology. At this time, in order to match the centers of the electron beam passing holes of the cold cathode and the electron gun electrodes, the cold cathode is combined with the electron gun to perform a process for determining the position.

For example, when the size of the electron emitting region is finally set to Φ 0.3 mm, the electron emitting region of the cold cathode is made large so as to include a positioning error generated in the manufacturing process, such as Φ 0.6 mm. .

Then, after combining the cold cathode with the electron gun as in the conventional method, except for the Φ 0.3 mm portion where the center of the electron gun electrodes coincides with the through hole, as shown in FIG. It is applied to the surface of the cathode through a method such as vapor deposition.

As shown in FIG. 8, masks 50 and 60 may be applied to the electron emitting efficiency of the electron gun electrodes in areas other than Φ0.3 mm where the centers of the electron gun electrodes coincide with each other. Edo positioning holes 52 and 62 are used to center the electron beam passing holes of the cold cathode support 30 and the adjacent electron gun electrode 40 using the positioning holes 52 and 62.

In FIG. 8, (a) shows a mask having a horizontal keyhole shape, and (b) shows a mask having a vertical keyhole shape. In the drawings, reference numerals 51 and 61 denote perforations of the mask, and 52 and 62 denote masking portions of the mask.

At this time, in order to deposit in the remaining parts except the center of a circular phi 0.3 mm, a combination of horizontal and vertical key hole shape masks 50 and 60 is used. If only the horizontal key hole mask 50 is used, no electron radiation will be generated in this portion since the masking portion 52 of the mask is not deposited on the horizontal straight portion other than the center portion.

Therefore, after the deposition using the horizontal keyhole-shaped mask 50, the combination of the vertical keyhole mask 60 is combined so that all of the cold cathode portions except the center portion are deposited with the electron emission suppressing material.

As an evaporation method, it is suitable to use an E-beam process having excellent straightness. Chemical vapor deposition, sputtering, and the like are diffusive and thus do not serve the purpose of local deposition using a mask. The guide pipe 70 is used to emit a material having poor electron emission efficiency through an e-beam process at the bottom of the guide pipe, and is selectively deposited on the cold cathode 20 using the masks 50 and 60.

By doing so, the cold cathode 20 is composed of the electron radiation cold cathode portion in which the electron emission suppressing substance is not deposited by the masking portions 52 and 62, and the electron emission suppressing substance deposited on the perforation portions 51 and 61. It is divided into radiation suppressed cold cathode portions.

That is, since the material having poor electron emission efficiency or the non-conductive material is selectively deposited only on the portion of the mask that passes through the perforations 51 and 61 of the mask, the electron beam is only deposited on the portion that is not deposited by the mask. Spinning takes place.

Various oxides, such as aluminum oxide (Al ₂ O ₃ ) and silicon oxide (SiO ₂ ), may be used as a material having poor electron emission efficiency to suppress electron emission.

On the other hand, if the straight portion is formed very thin among the masking portions 52 and 62 of the horizontal or vertical keyhole mask, it is possible to deposit in a desired form with only one without using two masks.

In this case, an E-beam process having excellent straightness may be used, and the chemical vapor deposition (chemical vapor deposition) having a medium diffusivity with a size slightly larger than the original deposition size of the center masking portion for masking the cold cathode may be used. Deposition can also be carried out locally on the desired region of the cold cathode.

According to the present invention, it is not influenced by the accumulated assembly error in the process of mounting the cold cathode in the electron gun, but only depends on the assembly error between the mask and the electron gun electrodes and the positioning hole of the mask and the position error of the mask. The overall position error can be limited to within ± 0.02mm.

Therefore, it is possible to effectively suppress the extreme aberration caused by the center mismatch between the cold cathode and the electron gun electron beam passing hole generated in the electron gun using the cold cathode, thereby improving the focus characteristics of the electron beam formed on the screen to improve the resolution on the screen.

Claims (5)

In an electron gun for a cathode ray tube employing a cold cathode, The cold cathode, An electron beam radiation cold cathode portion having a diameter of 0.3 mm or more around the emitter tip that emits the electron beam; The electron gun for a cathode ray tube employing a cold cathode, characterized in that the electron radiation suppressing material is applied to a region excluding the electron beam radiation cold cathode portion, the electron beam radiation suppression cold cathode portion is suppressed radiation of the electron beam. The method of claim 1, An electron gun for a cathode ray tube employing a cold cathode, characterized in that the electron beam suppressing material is an oxide. In the manufacturing method of the electron gun for cathode ray tubes employing the cold cathode, Finally attaching the cold cathode having a larger area than the desired electron beam emission region to the cold cathode support to bond the electron gun; A method of manufacturing an electron gun for a cathode ray tube employing a cold cathode, characterized in that the step of applying an electron emission suppressing material to the remaining area of the cold cathode except for the electron beam radiation region. The process of claim 3, wherein the step of applying the electron emission suppressing material, Finally, a method of manufacturing a cathode ray tube electron gun employing a cold cathode, characterized in that for using the mask electrode for depositing the electron emission suppressing material in the remaining region other than the desired electron beam radiation region. The process of claim 4, wherein the step of applying the electron emission suppressing material, Firstly applying an electron emission suppressing material through a horizontal keyhole-shaped mask electrode; A method for manufacturing a cathode ray tube electron gun employing a cold cathode, characterized in that the step of applying the electron emission suppressing material secondary to the vertical keyhole-shaped mask electrode.

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