KR0166929B1 - Improvement of inner potential of crt - Google Patents

Abstract

The present invention relates to a method for improving the breakdown voltage characteristic of a cathode ray tube, and more specifically, electrolytic polishing of each electrode constituting an electron gun, and then performing a knocking process including a G2 and G3-ground method. It is to improve the withstand voltage characteristics.

To this end, the first step of electropolishing the electrode constituting the electron gun, the second step of assembling each electrode passed through the first step, and the electron gun passed through the second step is sealed in the neck of the funnel A third step of evacuating the inside of the cathode ray tube and a high voltage is applied to the G6 electrode 6, which is the high voltage electrode of the electron gun, which has passed through the third step, and the low voltage electrodes G1, G2, G4 electrodes (1) (2) (4) And grounding the remaining electrodes, and performing a first knocking process by floating the remaining electrodes; and a fifth step of aging to remove the deposition material deposited on the electrode part after the fourth step; The high voltage was applied to the G6 electrode 6, which is the high voltage electrode of the electron gun, which passed through the fifth step, and the middle voltage electrodes G3, G5-B, C, D (3) (5b) (5c) (5d) were grounded, and the remaining electrodes were grounded. To perform the sixth step of performing the second knocking step by floating, or after the third step, After the implementation, the aging process is performed and the first knocking process is performed.

Description

How to improve the breakdown voltage characteristics of cathode ray tube

1 is a schematic diagram showing the configuration of an electron gun.

2 is a process diagram showing an embodiment of the present invention.

3 is a process diagram showing another embodiment of the present invention.

* Explanation of symbols for main parts of the drawings

1: G1 electrode 2: G2 electrode

3: G3 electrode 4: G4 electrode

5a: G5-A electrode 5b: G5-B electrode

5c: G5-C electrode 5d: G5-D electrode

The present invention relates to a method for improving the breakdown voltage characteristic of a cathode ray tube, and more specifically, a knocking process including a G2 and G3-ground method after electrolytic polishing and then assembling the G1 electrode and G2 electrode constituting the electron gun. This is to improve the withstand voltage characteristics of the cathode ray tube.

In general, a cathode ray tube is composed of a funnel coated with a fluorescent surface for obtaining an image, and a funnel in which an electron gun that radiates an electron beam to collide with the fluorescent surface is enclosed in a neck portion.

In order to obtain high quality in the cathode ray tube, a method of applying high pressure to the electron gun and the fluorescent surface is usually practiced.

However, when high pressure is applied to the electron gun and the fluorescent surface, the discharge phenomenon related to the electron gun is increased, and the gap sputter and light emission generated between the electrode of the electron gun and the insulating parts (beadgrass, neck part) are accompanied. There is a problem that the quality of the cathode ray tube is deteriorated due to the occurrence of vacuum breakage.

As a means for improving the above problems, a solution such as a floating knocking device disclosed in USP 4,214,798 and a metallized bead method disclosed in USP 18,907 is proposed. However, it was not enough to improve the problem.

In general, a method of manufacturing a cathode ray tube is inserted into a funnel through an opening formed in a neck portion and sealed, and then subjected to an exhaust process, followed by an aging process and a knocking process.

When high pressure is applied to each electrode of the electron gun during the process, stray emission is generated from the foreign matter or the projection of the electrode surface, and electron collision is caused between the electrodes, which causes sputtering. At the completion of the process, it is an absolute requirement that the cleanliness of the cathode ray tube, particularly foreign matter, is not present in the cathode ray tube, and that the electrode surface of the electron gun is smooth.

In order to alleviate this phenomenon, a knocking process is performed to remove or scatter foreign matters by forcibly discharging the electrodes by applying a high voltage, which is two to three times higher than the operating voltage of the cathode ray tube, during the process.

In addition, as a method for cleaning the surface of the electrode, a method of grounding a low voltage electrode and a medium voltage electrode and then applying a knocking voltage, which is a multiple of the normal voltage, to the anode and the high voltage electrode using a direct current pulse.

For example, in the case of a uni-potential electron gun, the first grid electrode (hereinafter referred to as G1 electrode) and the second grid electrode (hereinafter referred to as G2 electrode) and the fourth grid electrode (hereinafter referred to as G4 electrode) ) And the third grid electrode (hereinafter referred to as G3 electrode) and the fifth grid electrode (hereinafter referred to as G5 electrode) are applied with a voltage of about 60 KV, which is about twice the normal voltage, to clean the electrode surface.

Prior art USP 5,178,570 uses a partial pressure knocking method, in which the high pressure applied to the anode is divided by the high resistance connected to the G3 electrode, the G5 electrode, and the G6 electrode, the focusing electrode, to maximize the knocking phenomenon. In order to achieve the desired effect in the above method, proper resistance selection must be accompanied.

On the other hand, a method of applying a direct high pressure to clean the electrode of the electron gun is widely used.

That is, US Pat. No. 4,406,639 removes protrusions and foreign substances on the surface by dipping the electrode in a hydrogen peroxide solution to clean the electrode before knocking.

On the other hand, the dispenser cathode, which operates at a high temperature of 1000 ° C., tends to have more barium evaporation than the oxide cathode, and thus is easily deposited on the G1 electrode and G2 electrode, and the stray radiation is likely to occur because the temperature of the G1 electrode and G2 electrode is narrow.

In general, the knocking method is different depending on the wiring method and structure of the electron gun electrode. Therefore, in order to remove foreign substances from each electrode or to solve the stray radiation problem, it is necessary to select a knocking method suitable for the electron gun to be knocked.

Therefore, when there are many electrodes or long lengths of the electron gun, foreign substances are present on each electrode, which is more likely to cause stray radiation.In an electron gun having a dispenser cathode, barium evaporation is severe and G1 electrode, The high temperature of the G2 electrode is very disadvantageous for stray radiation, so it is difficult to solve by the knocking method.

The present invention has been made to solve such a problem in the prior art, in order to improve the withstand voltage characteristics of the cathode ray tube, the electrolytic polishing of the G1 electrode, G2 electrode constituting the electron gun when knocking G2 electrode-ground, G3 electrode -It aims to minimize stray radiation by carrying out knocking process by ground method.

According to an aspect of the present invention for achieving the above object, a first step of electropolishing the G1 electrode, G2 electrode adjacent to the dispenser cathode, a second step of assembling each electrode subjected to the first step, and A third step of encapsulating the electron gun subjected to the second step in the neck portion of the funnel and then evacuating the inside of the cathode ray tube, and aging to remove the deposition material deposited on each electrode of the electron gun passed through the third step Applying a high pressure to the G6 electrode which is the high voltage electrode of the electron gun which has undergone the fourth process and the fourth process, grounds the G1, G2 and G4 electrodes which are the low voltage electrodes, and floats the remaining electrodes to perform the first knocking process. Step 5 and applying a high pressure to the G6 electrode of the high voltage electrode of the electron gun that passed through the fifth step, ground the medium voltage electrodes G3, G5-B, C, D electrodes, and float the remaining electrodes to perform the second knocking process. The sixth hole to perform This improves the withstand voltage characteristic of the cathode ray tube characterized in the works, in turn is provided with a sphere.

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings of FIG. 1 as an embodiment.

1 is a schematic view showing the configuration of an electron gun, and the present invention provides a necked electron gun after electropolishing the G1 electrode and G2 electrode adjacent to the sub-penser cathode of the electron gun to improve the breakdown voltage characteristics of each electrode constituting the electron gun. After encapsulation and exhausting, the high voltage is applied to the G6 electrode 6, which is a high voltage electrode, and the G1, G2, G4 electrodes 1, 2, 4, which are low voltage electrodes, are grounded and the remaining electrodes are grounded. A first knocking process in which silver is floated, and a high voltage is applied to the G6 electrode 6, which is a high voltage electrode, and the G3, G5-B, C, D electrodes 3, 5b, 5c, and 5d, which are medium voltage electrodes, are grounded. The second electrode is successively subjected to the second knocking process of floating.

2 is a process diagram showing an embodiment of the present invention, in which the electrolytic polishing of the G1 electrode and the G2 electrode 1, 2 is performed before the mount assembly in the first process, and in the second process, the electrolytic polishing is performed. Assemble the polished G1 electrode, G2 electrode, dispenser cathode and the remaining electrode.

Next, in the third step, the assembled electron gun is inserted into the neck portion 7 of the funnel and sealed, and then the air is exhausted to the outside in the cathode ray tube.

In the fourth step, aging is performed to remove the deposition material deposited on each electrode of the electron gun.

In the fifth step, a high voltage of 65 to 80 KV is applied to the G6 electrode 6, which is a high voltage electrode, and the G1, G2, and G4 electrodes 1, 2, 4, which are low voltage electrodes, are grounded, and the remaining electrodes are floated. -Carry out the first knocking process including grounding;

In the sixth step, a high voltage of 65 to 85 KV is applied to the G6 electrode 6, which is a high voltage electrode, and the G3 electrodes 3, G5-B, C, D electrodes 5b, 5c, 5d, which are medium voltage electrodes, are grounded. In addition, the remaining electrode is floated and a second knocking process including a G3-ground method is performed.

Referring to the present invention carried out in such a process in more detail as follows.

In the first step, electrolytic polishing of the G1 electrode and the G2 electrode 1 (2) is performed before assembling the electron gun.

Chemicals for electropolishing use phosphoric acid (H ₂ PO ₄ ), sulfuric acid (H ₂ SO ₄ ), chromic acid (CrO ₃ ), pure water (H ₂ O) in an appropriate ratio, and the negative terminal of the power source. The electrode to be connected uses a nickel plate or a stained plate.

Therefore, the electrode of the electron gun to be polished is connected to the (+) terminal of the power supply and immersed in the mixed solution for about 2 to 5 minutes under a voltage of 5 to 10V for electrolysis.

Thereafter, the electropolished electrode is subjected to ultrasonic water washing, neutralization of ammonia, water washing, and rinsing off water, and then dried in a constant temperature room at 80 to 83 ° C. for at least 20 minutes.

In the second step, the mount assembly operation is performed including the dispenser cathode while being careful not to damage the electrode surface of the electropolished electron gun.

In the third step, the assembled electron gun is inserted into the neck portion of the funnel to be sealed and then evacuated.

In the fourth step, the cathode temperature of the dispenser is aged at 1100 to 1200 ° C. for less than 70 minutes.

This is because the cathode material is oxidized when the cathode temperature is higher than the above-mentioned temperature.

In the first knocking step including the G2-ground knocking method of the fifth step, the purpose is to clean the low voltage electrodes G4, G2, and G1 electrodes (4) (2) (1), where DC indirect knocking and induction knocking are performed. It is also possible to perform partial pressure knocking in parallel with the G2-ground knocking method.

In the G2-ground knocking method, the voltage applied to the G6 electrode 6, which is a high voltage electrode, can be applied with a DC voltage or a pulse voltage, similar to the G3-ground knocking method. It can be applied.

In the G2-ground knocking method, since only the low voltage electrodes G4, G2, and G1 electrodes 4, 2, and 1 are grounded, a high voltage can directly discharge the vicinity of the low voltage electrode.

In addition, since the G5-A, B, C, and D electrodes 5a, 5b, 5c, 5d, and G3 electrode 3 are floating, the electrodes can be cleaned by an organic voltage.

In the second knocking step including the G3-ground knocking method of the sixth step, the purpose is to clean the medium voltage electrodes G5 and G3 electrodes 5 and 3, wherein DC direct knocking, induction direct knocking, and G3-floating are performed. It is also possible to carry out knocking in parallel with the G3-ground knocking method.

In the G3-ground knocking method, a voltage applied to the G6 electrode 6 which is a high voltage electrode may be a DC voltage or a pulse voltage.

In the G3-ground knocking method, since only the medium voltage electrodes G5-B, C, and D electrodes 5b, 5c, 5d, and G3 electrodes 3 are grounded, a high voltage can directly discharge the vicinity of the medium voltage electrode. Will be.

In addition, when the G5-A, G4, and G2 electrodes 5a, 4, and 2 are floating, knocking can be expected due to an induced voltage.

That is, in one embodiment of the present invention, electrolytic polishing of the G1 electrode and the G2 electrode before the knocking step, and then knocking each electrode of the electron gun separately in the knocking step, can suppress stray radiation as much as possible.

3 is a process diagram showing another embodiment of the present invention, in which the aging step of the dispenser cathode is performed after the second knocking step and then the first knocking step is performed.

This is to reduce the phenomenon of deposition on each electrode by the evaporation of barium generated during the aging process, and at the same time to remove the deposition material and foreign matter stuck to the electrode surface in the knocking process as much as possible.

As described above, the present invention does not damage the neck portion 7 during knocking by minimizing stray radiation by electrolytically polishing the G1 electrode and the G2 electrode before encapsulating the electron gun in the cathode ray tube. The electrode of the electron gun can be cleaned.

In addition, by using a method including a G3-ground and a G2 electrode-ground method of grounding the target electrode in the knocking process, it can be applied to all electron guns regardless of the structure or wiring of the electron gun electrode. Since G3-based stray radiation can be effectively suppressed, it is possible to minimize image degradation due to stray radiation of the electron gun electrode to which the dispenser cathode is applied, thereby improving the withstand voltage characteristics and improving productivity. .

Claims (12)

A first step of electropolishing the G1 electrode and the G2 electrode constituting the electron gun, a second step of assembling the G1 electrode, the G2 electrode and the dispenser cathode, and the remaining electrode, which have been subjected to the first step, and the second step A third step of encapsulating the electron gun in the neck portion of the funnel and then evacuating the inside of the cathode ray tube; and a fourth step of aging to remove the deposited material deposited on the electrode part after the third step; A fifth step of applying a high voltage to the G6 electrode, which is the high voltage electrode of the electron gun which has passed through the fourth step, grounds the G3, G5-B, C, and D electrodes, which are the medium voltage electrodes, and performs the first knocking process by floating the remaining electrodes. And applying a high pressure to the G6 electrode, which is the high voltage electrode of the electron gun which has passed the fifth process, grounds the low voltage electrodes G1, G2, and G4 electrodes, and floats the remaining electrodes to perform the second knocking process. Characterized by To improve the breakdown voltage characteristics of a cathode ray tube. 2. The method of improving the breakdown voltage characteristic of a cathode ray tube according to claim 1, wherein only the G1 electrode is electropolished when electrolytically polishing the electrode in the first step. The method of improving the withstand voltage characteristic of a cathode ray tube according to claim 1, wherein indirect knocking, induction indirect knocking, and partial pressure knocking are performed in parallel when the first knocking step, which is a fifth step, is performed. 2. The method of improving the withstand voltage characteristic of a cathode ray tube according to claim 1, wherein the knocking, induction direct knocking, and G3-floating knocking are performed in parallel when the second knocking step is performed. According to claim 1, wherein the electrolytic polishing is performed by immersing the G1 electrode and G2 electrode in the electrolyte solution for about 2 to 5 minutes under the conditions that the voltage applied to the electrode in the first step is 5 ~ 10V or more, the current is 3A or less. A method of improving the breakdown voltage characteristic of a cathode ray tube characterized by the above-mentioned. The method according to claim 1, wherein the temperature of the dispenser cathode is aged at 1100 to 1200 ° C. for less than 70 minutes in the fourth step. A first step of electropolishing the G1 electrode and the G2 electrode constituting the electron gun, a second step of assembling the G1 electrode, the G2 electrode and the dispenser cathode, and the remaining electrode, which have been subjected to the first step, and the second step A third step of encapsulating the electron gun in the neck portion of the funnel and then evacuating the inside of the cathode ray tube, and applying a high voltage to the G6 electrode, which is the high voltage electrode of the electron gun, passed through the third step, and the low voltage electrodes G1, G2, and G4 electrodes A fifth step of performing a second knocking step by floating the remaining electrodes, and a fifth step of aging to remove the deposition material deposited on the electrode part after the fourth step, and the fifth step. The sixth step of applying a high pressure to the G6 electrode, which is a high voltage electrode, and grounding the G3, G5-B, C, D electrodes, which are the medium voltage electrodes, and floating the remaining electrodes to perform the first knocking process. Characterized in that To improve the breakdown voltage characteristics of a cathode ray tube. 8. The method of improving the breakdown voltage characteristic of a cathode ray tube according to claim 7, wherein only the G1 electrode is electropolished when electrolytically polishing the electrode in the first step. 8. The method of improving the breakdown voltage characteristic of a cathode ray tube according to claim 7, wherein indirect knocking, induction indirect knocking, and partial pressure knocking are performed in parallel when the first knocking step is performed. 8. The method of improving the breakdown voltage characteristic of a cathode ray tube according to claim 7, wherein when the second knocking step, the fourth knocking step, is performed, direct knocking, induction direct knocking, and G3-floating knocking are performed in parallel. 8. The electrolytic polishing according to claim 7, wherein the G1 electrode and the G2 electrode are immersed in the electrolyte solution for about 2 to 5 minutes under the condition that the voltage applied to the electrode is 5-10V or more and the current is 3A or less. A method of improving the breakdown voltage characteristic of a cathode ray tube characterized by the above-mentioned. 8. The method of claim 7, wherein the temperature of the dispenser cathode is aged at 70 ° C. for less than 70 minutes at the fifth step.