CS253209B1 - A method for gasifying barium from exothermic getters using a high frequency energy source - Google Patents

Abstract

The essence of the solution is that during high-frequency heating of the getter, the starting time is measured and its length is used to determine the total time corresponding to the nominal value of the evaporated barium mass recommended by the getter manufacturer for a given getter type. The solution can be used especially in television screens, where durability and reliability are the primary requirements and where it is essential to maintain the evaporated barium mass from the getter within a narrow tolerance.

Description

. SUMMARY OF THE INVENTION The present invention provides a method of gasifying barium from exothermic qetters using a high-frequency energy source in vacuum products, particularly television screens.

According to the known method, the exothermic, especially ring getter, is gasified by high-frequency heating by means of a high-frequency energy source with a fixed setting of the shoot. When gasifying the ring getter, two time slots are recognized. The first period of time from the start of the high-frequency heating of the ring getter to the time of the exothermic reaction is the start time. The second time period from the start of the high-frequency heating of the ring getter to the end of the high-frequency heating of the ring getter is the total time. The power of the RF energy source shall be set once for a given type of ring getter so that the start time corresponds to the recommendations of the getter manufacturer. The total time is set as recommended by the getter manufacturer. With the generator power and total time set in this way, the weight of the evaporated barium is not constant and is dependent on the change in the start time according to the curve given by the getter manufacturer.

The present method of gasification of exothermic getter has a number of disadvantages. The influence of the getter position relative to the RF energy flow on the weight of the evaporated barium is not eliminated. The actual value of the weight of vaporized barium is dependent on the actual position of the getter in the screen given to the getter assembly and the screen assembly. In the present method, the weight control of the evaporated barium from the getter at the screen is not sufficient. The lowest value of the weight of vaporized barium from the getter is a necessary condition of the screen lifetime specified by the screen manufacturer. In the current method, the length of the start time of the screen is not known, so it is essential that the person checking the progress should be carried out at regular intervals by a person who must be equipped with a stopwatch.

The aforementioned drawbacks are eliminated by the method of barium gasification from exothermic getters by means of a fixed power RF energy source according to the invention, characterized in that during the high frequency heating of the getter the start time is measured and its total time corresponding to the nominal weight of vaporized barium is determined. recommended by the getter manufacturer for the given getter type. The power of the RF energy source shall be set once, so that the length of the starting and total time corresponds to the getter's recommendations for the given getter type. For the boundary range of the start times given by the getter manufacturer, the corresponding total times are experimentally determined so that the weight of the evaporated barium always has the nominal value given by the getter manufacturer for the given getter type.

A new way of gasifying barium from exothermic getter is to achieve a constant weight of vaporized barium from the ring getter. The new method enables complete automation of the workplace for exothermic getter gasification, including automatic process control. The new method eliminates the effect of the actual getter position relative to the RF energy flow on the weight of vaporized barium and further allows to terminate the RF heating immediately after the start time has elapsed if its length is outside the range given by the getter manufacturer for the given getter type.

The accompanying drawings show an example of an embodiment of a method of barium gasification from exothermic getter according to the invention.

FIG. 1 shows the position of the RF energy source consisting of the RF generator 1 and the getter coil 2 relative to the cone 3 and the getter 4, which is part of the electron system 5. The optoelectronic sensor 6 is positioned relative to the ring getter to receive direct light emanating from the ring getter to produce an exothermic reaction. The output of the optoelectronic sensor 6 is connected to the input 23 of the start signal of the exothermic reaction of the control unit 7, whose output 24 is connected to the input of the high-frequency generator

Fig. 2 is a block diagram of the control unit 7.

The output of the clock source 11 is coupled to the input of the start time counter 12 and the input of the total time counter 13. The outputs of the start time counter 12 are connected to the inputs of the first display 14 and the memory 11 '. The outputs of the total time counter 13 are connected to the inputs of the second display 16 and the comparator 17. The control unit T is provided with a reset signal input 21, a start signal 22 input which is derived from starting the RF energy source and an exothermic start signal 23. from a flash of light accompanying the exothermic reaction. The control unit further comprises an output 24 of the RF power source shutdown signal.

To describe the operation, it is necessary to start from the reset state of the start time counter 12 and the total time counter 13. The start signal, which is applied to the start time signal input 22 and the total time counter 13, which counts the clock pulses from a source of 11 clock pulses. The start time counter 12 and the total time counter 13 operate as a stopwatch. The exothermic start signal that is applied to the exothermic start signal input 23 stops the operation of the start time counter 12.

The start time indication is indicated on the first display 14 and is simultaneously transmitted to the memory 15 where the corresponding start time length corresponds to the programmed total time value which is passed to the comparator 17. The comparator 17 compares this time with the time measured by the total time counter 13. When both times coincide, the comparator 17 commands the high-frequency generator 7 to output 24 and to stop the total time counter 13. The first display 14 indicates the start time, the second display 16 the total time until the reset pulse arrives at input 21. The condition of operation of the device in Fig. 2 is the programming of the memory 15 which must be performed based on expertly measured results within a possible start time.

Said barium gasification method from exothermic getter can be used for all exothermic getters doped and undoped for all vacuum elements by means of a control unit which allows to measure the start time and control the time of supplying high frequency energy to the getter.

The main application of the invention can be envisaged for television screens, where durability and reliability are a prime requirement and where it is essential to maintain the weight of the vaporized barium within close tolerances.

Claims (1)

SUBJECT OF THE INVENTION A method of gasifying barium from exothermic getter using a fixed power RF energy source, characterized in that during the high frequency heating of the getter, the start time is measured and the total time corresponding to the nominal weight of the evaporated barium is determined according to its length.