RU2254637C1 - Method for activating non-diffusive gas absorbers of cathode-ray tubes - Google Patents

Abstract

FIELD: electrovacuum engineering; electron-beam tube manufacture.

SUBSTANCE: proposed method involves activation of non-diffusive gas absorbers of cathode-ray tubes by heating them with infrared rays in wave band of 1.2 to 4.8 μm while feeding heater voltage to tube cathode. Halide filament lamp is used as infrared radiation source for the purpose. Titanium gas absorber is heated to 740 - 750°C at a rate of 395 to 400°C/min and exposed to this temperature for 2 - 2.5 minutes.

EFFECT: enhanced quality of cathode-ray tubes.

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Description

The invention relates to the field of electronic technology and can be used in electric vacuum production.

Known methods for the manufacture of cathode ray tubes, in which after pumping the device to activate the getter (GP). For example, the induction method of activating a GP is known, when the heating of a GP is carried out by exciting Foucault currents in them (see Shekhmeister EI, Production Technology of Electrovacuum Devices, Moscow: Vysshaya Shkola, 1992, p. 361 [1]) .

In the method of A.S. USSR No. 1074299, MPK7 H 01 J 9/00, 01/27/1996 [2] activation of non-sprayable GP is carried out after soldering the device by induction heating at a speed of 40-50 ° C / s to a temperature of 650-750 ° C. The choice of this range of temperature and heating rate provides high-speed diffusion deep into the crystal lattice of the GP gas molecules adsorbed on its surface and the decomposition products of the oxide film. The surface of the GP is freed to interact with the residual medium.

The disadvantages of these methods are the high cost of the equipment, the harmful effects of the high-frequency field on the operator, the difficulty of readjusting the processing of other types of electrovacuum devices.

In addition, field studies in the industrial conditions of induction heating showed that when the operator visually checks the degree of heating of the GP, which determines the quality of activation, it is often necessary to repeat the operation due to insufficient heating of the GP due to errors in the installation of the object relative to the inductor, which leads to a significant decrease in productivity.

The closest analogue of the proposed method can be considered a method of activating non-sprayed GP cathode ray tubes, disclosed in the source [1], according to which they produce radiation heating. Radial heating provides local heating of the GP without the danger of overheating of nearby parts, due to the possibility of focusing and concentration of radiation. However, with such a general formulation, the required heating efficiency of getters is not provided.

The objective of the invention is to improve the quality of cathode ray tubes through the use of precision infrared heating when activating the GP.

The technical result of the invention is to increase the efficiency of activation of getters when using external sources of infrared radiation by ensuring the optimal ratio of transmission of infrared radiation through the glass shell and its absorption by this shell to heat it.

The specified technical result is achieved by the fact that in the method of activating non-sprayed GP cathode ray tubes, including their beam heating while applying a filament voltage to the cathode of the cathode ray tube, the GP is heated by infrared radiation, the main part of the spectrum of which is in the wavelength range 1.2-4.8 μm, i.e. in the field of transparency and partial transparency of electrovacuum glasses. In this case, infrared radiation of a halogen incandescent lamp is used. Heating of titanium GP is carried out to a temperature of 740-750 ° C at a speed of 395-400 ° C / min and holding at this temperature for 2-2.5 minutes.

It has been established by calculation and experimentally that, in contrast to infrared heating, induction heating is more critical to changing the distance between the heater and the heating object. In particular, it follows that a change in the nominal distance between the heater and the heater by 5 mm leads to a decrease in the temperature of the heater by 47 ° C for induction heating and by 16 ° C with infrared heating. The discrepancy between the obtained theoretical dependences and experimental data does not exceed 15%.

In the inventive method, with spot heating of a GP by penetrating infrared radiation (IR), the precision of the heating method is significantly increased. In this case, the choice of the wavelength range λ = 1.2–4.8 μm is due to the fact that part of this radiation passing through the CRT glass at speeds of 395–400 ° C / min heats the HP, and the absorbed part ensures the glass is heated without breaking to a temperature of 250 -300 ° C / min, providing a decrease in heat transfer between the GP and the glass. When the wavelength range is mixed to the left, the glass heats slightly, and the heated GP gives off part of its heat to it, which leads to an increase in the heating time of the GP. When the wavelength range is shifted to the right, the glass transmits radiation less, which also increases the time of activation of the GP and requires an increase in the source power. In addition, this increases the likelihood of destruction of the glass at the indicated heating rates.

Concrete example

According to this method, titanium GPs of cathode ray tubes with a thickness of δ <2 mm are activated as follows. IR heating is carried out by a halogen incandescent lamp (GLN) of the type KGM 24-250, the main part of the spectrum (75-80% of the radiation flux) of which at a filament body temperature T = 2000-2200 ° C is in the wavelength range λ = 1.2-4 , 8 microns. Part of the radiation in this range of GLN penetrates the glass shell, heating the GP. The part of the radiation of the specified wavelength range absorbed by the glass shell heats it, thereby reducing the heat loss flux from the GP to the glass shell, which in turn leads to a decrease in the heating time. In this case, during heating of the GP, the filament voltage U _nak = 6.3 V is applied to the cathode of the cathode ray tube. The voltage of the filament serves to heat the cathode in order to prevent sorption of gases released during the processing of the GP. Heating is carried out at a speed of 395-400 ° C / min to a temperature of 740-750 ° C. Then produce exposure at a given temperature for 2-2.5 minutes and turn off the heaters.

Claims (2)

1. A method of activating non-sprayable getters (GPs) of cathode ray tubes, including their beam heating while applying a filament voltage to the cathode of the cathode ray tube, characterized in that the GP is heated using infrared radiation from a halogen incandescent lamp with a wavelength range of 1.2 -4.8 microns. 2. The method according to claim 1, characterized in that the heating of the titanium GP is carried out to a temperature of 740-750 ° C at a speed of 395-400 ° C / min and exposure is carried out at this temperature for 2-2.5 minutes.