SU693461A1 - Method of manufacturing photocathode in television pick-up tubes - Google Patents

Description

I.

The invention relates to the field of electronic instrumentation, namely, to a method for producing a photocathode in television transmission tubes, such as super-orcon or isocon .:

A known method of manufacturing a translucent photocathode in a television tube, comprising the manufacture of a cathode based on compounds of group A

However, the cathode manufactured by this method has low sensitivity for wavelengths greater than 0.8 μm.

A known method of manufacturing a translucent photocathode in a television transmission tube involves mounting the fixture of the device, applying a layer of base metal by vacuum evaporation to the inner surface of the entrance window with an active alkali metal sensitization and sensitization 2.

With this technology, a silver layer is applied with a transparency of 4O-50% isHeHHeM in vacuum, then oxidized in an oxygen atmosphere until the transparency changes to 90-100%, an additional layer of silver is applied until the transparency changes to 6O-80%.

The disadvantage of this method is the low percentage of output devices for resolution.

The purpose of the invention is to increase the resolution of the tube and the percentage of output in this parameter.

To achieve the goal, 40–80% of the required amount of metal is deposited in the tube before mounting the slider assembly, and the rest - during the vacuum treatment of the tube.

Claims (2)

The thickness of the first metal layer applied to the faceplate prior to placing the target in the tube may vary with within wide limits (40-80%). Its minimum thickness should ensure that the glass surface is covered with a continuous metal layer, max 1 sak only in this case it is possible 1% tritrilement of 36 metal particles that feed the faceplate during the second stage of the photocathode, and the maximum is limited by the sensitivity of the photocathode. The thickness of the second layer (60–20%) is related to the thickness of the first layer so that the total layer is obtained of the optimum thickness to obtain the maximum sensitivity of the photocathode produced according to the received tehpopbgin. An example of the implementation of the proposed method is the manufacture in laboratory conditions of ten pieces of instruments LI232. First, using a suitable tool (a punch, molds, a dividing machine, and.), Glass and mechanical parts of the device are made in 1s. After chemical and mechanical processing (removal of contaminated sandblasting, electrolysis) and coating of glass parts on special mandrels, the assembly of parts into nodes (transfer section, antenna and multiplier) is carried out. With the help of appropriate tools, these assemblies are fastened on a glass cylinder and an inlet foot. At the same time, on a glass plate with a glass unsea, an aluminum contact ring is applied under a vacuum cap at a pressure of 1.Hg. silver is deposited by evaporation. To prevent silver from falling onto the cylindrical wall of the glass, a special metal screen is placed into it. The thickness of the applied layer is controlled by the loss of transparency with the help of an illuminator and a selenium frtoement with a microammeter. The evaporation process stops after a loss of transparency of 25%. Then the beaker is welded to the flange of the glass cylinder, and you are installed. Complete the last assembly operation of the device - welding the input leg with the spotlight multiplier system mounted on it. The assembled device is soldered to a vacuum post, and in advance the furnace is put on its cylinder to warm up the multiplier, then lower the furnace to the general heating of the device. During pumping by a high-vacuum pump, both furnaces are turned on at temperatures of respectively 5OO From the multiplier furnace and ZOO From the common furnace, the appliance is degassing: At a pressure of 1.3 Y.mm Hg. the furnace of the general warming up is off. 4 yuchayut and lift. When the furnace is switched on, the multiplier for its oxidation introduces oxygen into the device for 10 minutes at a pressure of 1 mm Hg. After the pumping of oxygen, the total warming up pump is lowered again. Warming up with pumping continues to a pressure of 1-3.10 mm Hg. Then, both furnaces are turned off, the device is cooled, and the source of cesium is degassing and the thermal insulation is activated. The last step is making a photocathode. For this, the thickness of the applied additional layer of silver with light absorption by an additional 25% instead of 50% according to standard technology is controlled using an illuminator and a selenium photocell, since 25% was applied to the plate beforehand. Oxygen is introduced into the device at a pressure of 2.10 mm Hg. Art. and the spoil is oxidized by HF discharge so that its transparency increases from 60 to 7 -75%. A general heating furnace is lowered, and after the device is heated for 30 minutes at a temperature of 170-180 ° C, a current is passed through the cesium source, the photocell is sensed. The process control is produced by the photocurrent. At first, the current appears, increases, passes through a maximum and decreases by 20-30%. At this point, the current through the cesium source is turned off, and the device continues to warm up until the photocurrent stabilizes. Then the furnace is raised, the device is cooled, and the photocathode is sensitized. For this, observing the photocurrent, turn on and gradually increase the current through the silver evaporator. As a rule, the photocurrent increases, passes through a maximum and decreases by 30–30%, then the current through the evaporator is exhausted. After that, the device warms up at 17 O-180 C to the maximum of the photocurrent and then cools. Oxygen is carefully introduced into the cold instrument with control through the photocurrent. When the photocurrent, having passed through a maximum, drops by 10-20%, the sensitization of the photocathode is considered complete. Then the gas absorbers are evaporated, the thermal cathode is trained and the device is sealed off. Claim method for making photocathode in television transmission tubes, 693461.6 installation of the reinforcement, the application of the main metapp, and the rest - in base metal by vacuum using a tube, vacuum tube processing. soaring on the inner tyuverhnost., - the input window with the subsequent KSH activate- Sources of information. alkali metal and sensi-5. locio apy Dit,., New tiigll bipization, different sensi-t-ivifs tongr-tife image or ticons, By the fact that, with the purpose of raising, I allow-Tostiiba, 966,23, l7, p.9ov-9-12 (1). tube capacity and increase 2.Sunivplsa i M., Vegte V.P-t) evee.opsentu output w this parameter, before unt about sitven-ox.xgen pViotocoiitiocls (by mounting the target assembly in a nano- ° Tudifen Tornat oi riga phvsics 9 tube, with t 4O-80% of the required amount of 191-1 ,, (21) (prototype). taken into account during the examination