JPH01169840A - Cathode-ray tube processing method for improvement of withstand voltage characteristic - Google Patents

Abstract

PURPOSE:To have good voltage withstand characteristics by changing and reversing the polarities of impressed voltage during spot knocking treatment. CONSTITUTION:The polarities of the voltage impressed on a cathode-ray tube are exchanged and reversed on the way of the treatment process. Therefore, inside the cathode-ray tube is every where impacted by a number of electrons, and totally viewed a sufficient spot knocking effect is obtained with a comparatively short voltage impression time and low impressed voltage value. This enables cleaning of different places with a comparatively low impressed voltage and short voltage impression time to lead to enhancement of the withstand voltage characteristics.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is directed to a so-called spot non-king treatment, which is used to improve the voltage resistance characteristics of color cathode ray tubes and the like, in which a relatively high voltage is applied between electrodes. Regarding improvements.

[Conventional technology]

Before proceeding to the sealing and evacuation processes for cathode ray tubes, efforts are made to clean the inner walls of the bulb, each electrode, and the surfaces of the insulators that support the electrodes as much as possible to obtain good withstand voltage characteristics. However, in general, this alone does not provide sufficiently stable withstand voltage characteristics, so conventionally a so-called spot knocking process has been carried out, in which a voltage higher than the actual operating state is applied for a predetermined period of time between each electrode in the cathode ray tube after the evacuation is finished. I was worried.

Traditionally, in the spot non-king process, a DC power supply or an induction coil is used as the power source, and the cathode terminal of the stem is usually grounded and connected to the cathode of the power source, and the anode of the power source is connected to the anode terminal in the funnel. Therefore, overt knocking was performed by applying a higher voltage by increasing the voltage step by step starting from a low voltage. Figure 2 is a diagram showing a conventional spot knocking treatment method. In the figure, ■ is a voltage control circuit that determines the high voltage to be generated on the secondary side, 2 is a high voltage generation circuit, and 3a and 3b are output terminals. , 4 is a cathode ray tube to be processed, 5 is a cathode terminal on the stem of the cathode ray tube, and 6 is an anode terminal on the funnel of the cathode ray tube. The voltage supplied to the primary side of the high voltage generation circuit 2 is usually a relatively low DC voltage, and the negative side DC current value gradually increases.
When a certain predetermined value is reached, this direct current is suddenly reduced and cut off, and at this time a high voltage is generated on the secondary side. Therefore, a high voltage generation circuit is similar to a transformer, but its output voltage is high in a specific direction (low in the opposite direction).

However, even with the spot non-king described above, it is difficult to obtain the desired withstand voltage characteristics, and in order to obtain sufficient withstand voltage characteristics, a high applied voltage and a long voltage application time are required. As a result, there were side effects such as deterioration of the electron emission characteristics of the cathode, cranking of the bead glass that insulates and supports each electrode of the electron gun, and in some cases cranking of the pulp neck tube.

[Problem that the invention seeks to solve]

The present invention has fewer adverse effects due to the above-mentioned side effects,
Moreover, it is an object of the present invention to provide a spot knocking method that provides sufficiently good withstand voltage characteristics.

[Means for solving problems]

In order to solve the above problems, in the present invention, the polarity of the applied voltage is exchanged or reversed during the spot knocking process. That is, it was decided that the direction of voltage application was alternately reversed between positive and reverse voltages.

[Effect]

The withstand voltage characteristics of a cathode ray tube are improved by removing contaminants and foreign substances that remain or adhere to each part inside the tube, such as the electrode surface and the insulator surface that supports the electrodes. , electrons emitted by a strong electric field mainly from locations at negative potential (contaminated surfaces generally tend to emit electrons, and attached foreign matter can cause electric field concentration, which can easily cause discharge)
It is thought that when the electrolyte collides with an area at positive potential, pollutants and foreign objects from the area that received the electric shock are removed.

Even after the exhaust process is complete, a small amount of gas still exists inside the cathode ray tube, so the gas molecules are bombarded with electrons and ionized.
The positive ions generated in this way are accelerated by the electric field caused by the application of high voltage and move in the opposite direction to the electrons, impacting areas at negative potential and cleaning those areas, but the cleaning effect of a small number of ions is Even if the large momentum of ions is considered, the cleaning effect is considered to be small compared to the cleaning effect of a large number of electrons. This is considered to be the reason why the withstand voltage characteristics were able to be improved by applying a high potential for a long time even with the conventional spot knocking caused by applying a unidirectional electric field.

On the other hand, according to the present invention, during spot nonking, the polarity of the high potential applied to each part of the cathode ray tube is exchanged or reversed, so unlike the conventional method, each part is cleaned by the impact of a relatively large number of electrons. As a result, each part can be sufficiently cleaned even with a relatively lower applied voltage and shorter voltage application time than before, and at the same time, there is no negative effect of spot non-king as in the past. seems to be suppressed.

〔Example〕

FIG. 1 is a diagram showing an embodiment of the present invention, and the reference numerals in the diagram are the same as those in the conventional case shown in FIG.

In the present invention, as shown in this figure (upper and lower right side), the polarity of the voltage applied to the cathode ray tube is changed during the processing process.
Reverse it. By doing this, each part of the cathode ray tube is
Everywhere is bombarded with a larger number of electrons than in the past, and overall a sufficient spot non-king effect can be obtained with a relatively short voltage application time and low applied voltage value.

〔Effect of the invention〕

As explained above, according to the present invention, compared to the conventional
With a short voltage application time and a low applied voltage value, a sufficient spot non-king effect can be obtained, and the adverse effects of side effects that conventionally occur during spot knocking can be avoided.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an embodiment of the present invention, and FIG. 2 is a diagram showing a conventional spot non-king process.

Claims (1)

[Claims] 1. In order to improve the withstand voltage characteristics between each electrode in the cathode ray tube, a voltage higher than that under actual use is applied between the electrodes of the cathode ray tube for a predetermined period of time after evacuation. A method for improving withstand voltage characteristics of a cathode ray tube, characterized in that the polarity of the tube is exchanged and reversed.