DE1928013B2 - METHOD OF MANUFACTURING A CATHODE TUBE WITH ALKALINE HALOGENIDE SCREEN - Google Patents

Description

The invention relates to a method of manufacturing a cathode ray tube having a evaporated on the inside of the front plate of the tubular flask · alkali halide screen, in which the Tubular flasks divided into at least two parts melted together after the evaporation of the screen will.

Typical electron tubes that use an alkali halide plate use are secondary electron multiplier tubes and image intensifier tubes in which the special characteristics of the vapor-deposited alkali halide used as a secondary electron-emitting surface with high quality works. The surface of the alkali halide crystals is irradiated with electron beams, known as c .. is, wherein an optical absorption band (F band) is induced in the crystals, which is usually is referred to as an F-center. This phenomenon leads to the storage of optical information and is often used to form an image storage tube. In the following description become the electron tubes using an evaporated alkali halide plate for simplification the explanation using the example of an image storage tube: it should be emphasized, however, that the electron tubes of this type have a variety of other practical uses.

If the surfaces of the fine alkali halide crystals are to work effectively, the crystals may don't get wet. Most alkali halide crystals, however, are extremely hygroscopic. Should the deposited alkali halide layer in a storage tube, in which a subsequent Melting together is required, then difficulties arise when moisture, for example by not pre-dried air or by the combustion gases of an oas burner in the flask penetrates the tube.

The invention is based on the object of creating a method of the type mentioned at the outset, by simply taking up the piston parts when the piston parts are melted together moisture penetrating through the alkali halide screen is avoided.

This object is achieved in that during the fusing of the Kolbenteüe and the part of the The bulb carrying the alkali halide screen is heated.

Advantageously, the part of the bulb which carries the alkali halide screen is brought to a temperature heated between 50 and 400 C.

The following description using schematic drawings shows the disadvantages which one in the previous methods of manufacture

ίο the alkali halide storage layer on the screen or Has found counter plate of a storage tube, as well as the advantages of the method according to the invention compared to the known methods.

F ί g. 1 to 3 show different types of

t5 Evaporation of the alkali halide crystals and the Sealing the tubular piston as previously carried out;

F i g. 4 shows the type of sealing of the piston of a storage tube according to the invention.

so there is a storage tube of known construction according to the drawings essentially consisting of a glass bulb 1 with an enclosed Elektiunenstrahletr.eugersystem 2 and a plate-shaped counter electrode 3. the one on the inner end face of the piston 1 is attached. A storage layer 4 is fixed on the inner surface of the counter electrode 3 Alkali halide attached, onto which 2 electron beams are ejected from the beam generator system to write desired optical information on the disk.

In order to be able to vaporize the alkali halide crystals on this plate 3 in one of the previously used vename types, the alkali shark "genide crystals 4" are carried by a metal crucible 5 which is attached to the plate 3 in the previously evacuated and hermetically sealed flask 1 under a ■ facing the right angle. The crucible is then heated by means of a high frequency coil 6 to which a high frequency current of the order of 400 kilohertz is applied so that the alkali halide crystals 4 'carried by the crucible 5 are melted. The molten alkali halide crystals are evaporated and brought into adhesive contact with the inner surface of the plate 3. This type of evaporation has a disadvantage that it is difficult and impossible to control the thickness distribution of the alkali halide layer. reliably determine the angle / u at which the alkali halide vapor is directed onto the plate. Figure 2 shows another known method which has been developed to overcome these disadvantages. This method differs from that according to FIG. 1 in that the crucible is moved towards the outside of the piston

SS can.

As can be seen, the crucible 5 carrying the alkali halide crystals 4 ′ is supported by a support rod 7 carried inside a tubular extension 8 worked on the wall of the piston extends outward from the piston. At the other end of the support rod 7 there is a magnetic one Element 9, through which the rod 7 and, accordingly, the crucible S connected to it below Guided tour through the between the crucible and the

Magnetic element arranged guide piece 10 can be moved. The crucible S can thus without Difficulty and quick to align in the center of the cross-section of the piston by moving the rod 7

τι

moved with the aid of Mugnetelements 9, so the diiß The inventive method is at the waste ^V i "ι ·" V ^{Iege lllls} ß ^eliende Alkalihalogeniddampf dicluungsvorgang of Figure 3 applicable. it will

Equally applied to the inner surface of the plate 3, however, in connection with the type of seal

is ilarnplt. The heating of the crucible is done with the previously meticulous working methods explained

l-lΜIe of a high-frequency coil 6 required in the same way 5, but the increased practical importance

^like _NI ^hey ! ^Fl _l f · ¹ · tung receives.

After preparing the alkali halide storage die F i g. 4 shows schematically a preferred ßei- ^ CIiClU 4, the crucible 5 from the piston in the game for the method according to the invention, in which the ronrlormige extension8 is moved by the glass bulb 1 laterally in two parts la and Ib magnetic element 9 by pressing a is appropriately subdivided by a gap 16, which is at a suitable distance from the outside with a magnet (not shown), which can even be as short as 5 cm ^, r ... ¹¹ " ^{61 inside the} crucible , from the front end of the piston! to the tubular extension 8, the extension of evaporation of the alkali halide crystals to the plane marked with P is sealed and counter-plate 3 to facilitate.

the superfluous section of the extension is removed. 15 If a piston with an enlarged piston face

separates. The evaporation of the alkali halide crystals used surface, so it can be loaded at a section

can thus be carried out with this procedure severed significantly increased cross-sectional area

without the crucible remaining in the flask. so that it is possible to

v TT, ^{disadvantages of the first} example of the known area of the piston with a counter electrode previously

Methods are also used to apply another known vapor deposited alkali halide layer.

Method for which an example is overcome in After the formation of the alkali halide layer 4

'n' ^{3 is} shown. on the plate 3, the cut ends of the parts 1 a

In the third method, the diesei.i Alkalihalo- and 1b by heating the corresponding waste

gemdschicht 4 hermetically sealed before the onset of the electron cut. Heating the

Beam generator system 2 in the piston on the plate 3 25 cut ends of the Teilcia and Ib can with aids

educated. It is then the beam generator system 2 with a gas burner 17 on the entire circumference of the ends

With the aid of a support element 12 on the glass base 1. According to the invention, the alkalihalo-

Vi ¹ K ^1- Tu ¹ " ^{Glasfuß11 is} then on the genidschicht 4 when closing the gap between

Piston 1 is fixed, by glass processing, the parts la and 1b held in a heated condition,

those following the 30 described below in order to prevent the layer of water

bstep is made. As long as the glass base 11 absorbs steam that is caused by combustion on the gas

Once it is released from the piston 1, there is a burner 17 is generated. The facility for the

see them a distance 13 as shown. When the alkali halide layer 4 is heated, this

i ^lS u ^{denotes a gas burner} , with which the end case is essentially provided by a heating element 18,

portion of the piston for the preparation of a dense 35 ^e 'nen holder 19 for holding the heating element to

The connection with the glass stem 11 is heated. the piston 1 and for the transfer of the heat

Through a supply 15, a dry air stream is formed that section of the piston, which in turn

'δκ λ ^{efuhrt 11, a} ß · ^initially exceeded by the heat to the alkali halide 4

Distance 13 / between the piston 1 and the glass carries, and also by a shaft 20 which is attached to a

IULWI and after closing the distance through 40 end is connected to the heating element and to the

Set the distance between the glass base 11 and the other end with a rotating device (not

passage 15 escapes. In this way the shows) to the piston 1 during the closing) »

iich from the combustion through the gas burner 14 of the gap 16 opposite the gas burner 17

To be able to rotate Dildenrle water vapor essentially from the Al-

Kalihalogciiidschicht 4 kept away. 45 The heating element 18 is expediently arranged

You can see that! with the latter two net that there is the alkali halide layer: 4 to one

Examples for establishing an evacuated storage temperature in the range between 100 and 400 C

Cner pipes with alkali halide layer cumbersome heats, although those at a temperature of 50 to

Operations are unavoidable in order to either achieve the 100 C results with justifiable

liegci to remove from the inside of the piston 50 pleasure in terms of performance are acceptable

Or around during the sealing dry air in de ;: Since the alkali halide layer simultaneously with the

To blow the piston, although certain preheating of the cut ends of the parts 1 α and Ib des

parts are obtained thereby. that the crucible flask I is heated, it is protected from it,

removed or that the alkali halide layer to absorb moisture to such an extent

Protected from moistening. ₅₅ beers. that the layer is no longer the formation of a

All of the aforementioned disadvantages, which the known F-centrun., Allowed. The separation of the piston 1

ten \ experienced own, can be made easier by the inven- ting the rest of the accuracy

according to the method can be avoided without the formation of the halogen foreign layer, since the alkali halogen

Cumbersome work steps and devices necessary crystals arranged sufficiently close to the plate

become agile. _6o can be.

1 sheet of drawings

Claims (2)

Claim: 1. A method for producing a cathode ray tube with an alkali halide screen vapor-deposited on the inside of the front plate of the tube bulb, in which the tube bulb, which is divided into at least two parts, is melted together after the vapor deposition of the screen, characterized in that during the fusing of the bulb parts (la. Ib) the part (la) of the bulb which carries the alkali halide screen (4) is also heated. 2. The method according to claim 1, characterized in that the part (la) of the piston, which carries the alkali halide screen, is heated to a temperature between 50 and 400- C.