DE2905263C2 - Method for the vacuum-tight connection of a front plate of an image recording tube, which is provided on its inside with a charge storage plate, to the open end of a tube piston - Google Patents

Description

tion (89) to be under pressure by supplying power through 25. The indium required is also very expensive. Since the cloth (83a. Fßb) is heated to a temperature the limit temperature of the vapor-deposited film of the previous vidicon using antimony trisulfide in an inactive or inert gas atmosphere at most

becomes, in which the liquid ur.d is the solid phase of the Solder alloy (89) are present at the same time. 2. The method according to claim 1, characterized in-170 ° C is the described cold press fastening

draws that in a manner known per se, the Lötle- 30 supply method using metallic

alloy to a solder alloy ring (62) with an inner diameter practically corresponding to the Diameter of the opening d "tubular piston (5) shaped and between the peripheral edge of the inner surface the front plate (6) and. · ': S the open end of the tubular piston (5) is inserted.

3. The method according to claim 1 or 2, characterized in that that ultrasonic vibrations are also applied at the same time as the pressure.

4. The method according to claim 2, characterized in that the solder alloy ring (62) is provided with a plurality of tabs (62a, 62b) and is heated by supplying power via these tabs (62a, 62b).

High purity indium applied. Because of the melting point of metallic indium at 156 ° C the firing temperature for the gas expulsion is limited to 120 to 130 ° C, with the result that the Gas from the tubular piston 5 and the front plate 6 and in the vicinity of these parts only incompletely expelled will.

From DE-OS 23 33 386 a method is the initially named type known in which the connection between the front plate and tubular piston in the manner is made that after coating at least the peripheral edge of the inner surface of the faceplate and / or the open end of the tubular piston with a solder alloy which mainly contains lead, the solder alloy is heated under pressure. This is intended to make the front plate and tube piston vacuum-tight with one another get connected. The ones needed to connect

The invention relates to a method for vacuum temperatures are quite high, tight connection of one on its inside with one Further from Ulimann's Encyclopedia of tech

Charge storage plate provided front plate of a 50 niche chemistry, 3rd edition, 12th volume. Munich 1960, Image pickup tube with the open end of a raw side 51, lead, tin and antimony soldering alloy iron known according to the preamble of the patent applications, reference being made to the fact that Spruchs 1. it may be desirable for certain purposes. Plumb bobs with

In a conventional image pick-up tube, a frontal interval is an extended freezing interval, i. H. one Plate made of glass, which is a charge storage plate with an on-55 temperature range in which the liquid and the solid successively formed, transparent, conductive phase are present at the same time, to be used.

Finally, from DE-OS 23 08 041 a solder alloy is known which contains lead, tin, antimony and zinc. This is to a solder alloy r.iit a Anwendungsbo temperature be provided through 180 ^e C.

It is now the object of the invention to provide that mentioned at the beginning To improve the process so that the solder alloy is heated as evenly as possible in a simple manner can be.

This object is achieved according to the invention in a method according to the preamble of patent claim I. by those contained in its characterizing part

and photoconductive layers, airtight with a Tubular piston made of glass connected or welded, one end of which is closed and the other end of which is open.

For a vidicon in which the photoconductive layer is made of antimony trisulfide, a cold press attachment process is used using high purity metallic indium for the airtight connection of the Front plate applied to the tubular flask. In particular, according to FIG. 1A, metallic indium is used attached to the inner surface of an annular signal electrode. Then that becomes a bulge Features solved.

Advantageous further developments of the invention emerge from patent claims 2 to 4.

In the invention, a metal ring, the diameter of which is practically the opening diameter of the Tubular piston corresponds, together with the solder alloy between the peripheral portion of the inner surface the front plate and the open end of the tubular piston is arranged Solder alloy by supplying power to the metal ring and while applying pressure to the specified Temperature heated. With simultaneous application of ultrasonic vibrations with the application of pressure the necessary pressure can be reduced.

The following are preferred embodiments of the invention in comparison with the prior art the drawing explained in more detail

FIGS. 1A to IC are sectional views for illustration a previous procedure,

2 shows a longitudinal section through a complete Image pickup tube,

F i g. 3A and 3B show an embodiment of the solder alloy ring for the actual procedure,

F i g. 4 is a partially sectioned illustration the connection of the front plate with the tubular piston by means of the solder alloy ring shown in Fig. 3A and 3B,

5 shows a further embodiment of the connection the front plate with the tube piston,

6A and 6B an embodiment of the metal ring and

Fi g. 7 a fig. 5 similar representation of another Modification of the connection.

F i g. Fig. 2 illustrates an image pickup tube at which has a tubular bulb 5 made of glass, which has an open and a closed end, at its open end a glass front panel 6 connected to it with an airtight seal is provided at the junction between the tubular piston 5 and the front plate 6 is an annular around both parts Signal electrode 1 arranged. A transparent conductive layer 8 and a photoconductive layer 9 are Applied one above the other to the inner surface of the front panel 6. These layers 8 and 9 form a photoelectric Charge storage plate 10, the layer 8 being conductively connected to the signal electrode 1. in the Tubular piston 5 are four electrodes 13, 14, 15, 16 in succession at certain distances from one another and coaxially to one containing a filament 11 Electrode 12 arranged. The filament 11 and electrodes 12 to 16 each have different lead pins 17 connected, which pass through a tube shaft 5a and of which the clear wedge in the drawing not all are shown for the sake of The first to third electrodes 13, 14 and 15 are supported by support elements carried by an insulating rod, not shown. The fourth electrode 16 in the form of a grid electrode the photoconductive layer 9 is arranged opposite.

In one embodiment of the invention, a solder alloy ring 62 of the type shown in FIG. 3A and 3B are punched out of a Lötmetallplatte having a melting point of 180 to 200 ⁰ C. The solder alloy ring 62 has two radially outwardly projecting tabs 62a and 62f>. The thickness t is 0.05 to 0.5 mm. The greater the thickness t , the smaller the width d must be. Good results are obtained with f · ά <- get ■ 0.05-0.3 mm ^2. The width W of the two lobes 62a and 62i> is about 2J with a length / of more aiι d.

First, a first tubular guide piece 73 made of ceramic or the like after an appropriate arrangement the electrodes, not shown, are provided around the open end portion of the tubular piston 5 so that that the upper end surface of the guide piece 73 is flush with the surface of the tube piston opening. The solder alloy ring 62 is then placed on the guide piece 73 and on the open end section. Furthermore, according to FIG. 4 a second tubular

ίο Guide piece 74 placed on the solder alloy ring 62. The two tabs 62a and 62Z> of the soldering metal ring 62 protrude outward over the guide pieces 73 and 74. Next, the front plate 6, provided on its inner surface with the vapor-deposited photoelectric charge storage plate (not shown _{), is placed on the soldering alloy ring 62, whereupon the space in the area of the charge storage plate is filled with an inert gas (e.g. N 2} , Ar or He). A press plate 75 made of ceramic or the like is then placed on the front plate 6 and subjected to a DnHc fin of the order of 20 to 200 bar (z the pressure exerted by it can be reduced to 0.2 to 20 bar. The tabs 62a and 626 of the solder alloy ring 62, which protrude beyond the conductive pieces 73 and 74, are connected to electrodes 78 and 79 for supplying current. The current supply is continued until the temperature at the circumferential area of the front plate 6, at the soldering alloy ring 62 and at the open end of the tubular piston 5 is slightly below 160 to 180 ° C and at most 165 - 185 ° C. If the temperature increases within a period of less than 5 s, the front plate 6 or the tubular piston 5 can suffer damage. The temperature increase therefore takes place over a period of 10 seconds or more. After the seal has been produced, the arrangement can be removed from the device ^{at a temperature of 150 ° C. or below.}

In the case of the in FIG. 5 shown modification is a metal ring 83 with a practically the same diameter of the Söhrenkolbens 5 corresponding inner diameter in connection with a Lötiegierung 89, which mainly Contains Pb and Sn as well as some Sb and Zn (e.g.

20-60 wt% Pb, 10-70 wt% Sn, 0.1-10 wt% Sb and 0.1-10 wt% Zn), between the peripheral edge of the inner surface of the faceplate 6 and the open end of the tubular piston 5 inserted the Solder alloy can also contain CaI and! N. The an-order is then in this state under simultaneous Applying pressure is heated to a temperature at which the liquid and solid phases of the Lötlegievung 89 exist at the same time. This temperature is higher than the melting point of 156 ° C of metallic indium, so that the firing temperature for the gas drive is raised to a value in which the charge storage disk 10 is still stable.

The arrangement of the soldering alloy 89 on the circumferential edge of the inner surface dec front plate 6 and on the open end of the Röhienkolbens 5 can take place in the manner described above. According to FIG. 6A and 6B, the metal ring 83 has two diametrically opposed tabs 83a and 836. In the form shown, the metal ring 83 is made of a metal sheet made of e.g. B. punched out copper, iron, nickel or the like, which has good adhesion for the soldering alloy 89. The thickness to of the metal ring is preferably 0.02 mm

or more. The width w of each lobe 83 'and 836 is about 2c /, while the length / of each lobe is 2c / or more. If necessary, the metal ring 83 can be coated in advance on one of both surfaces with soldering metal. In this case, either of the metal ring 83 are punched out of the coated with a solder having a melting point of 200 to 250 ⁰ C, the metal sheet or is subjected to ultrasonic vibration of the stamped metal ring are immersed in a Lötlegierungsschmelze 83. The thickness ii of the applied solder alloy layer is 0.02 to 0.5 mm; good results are obtained with fi · d · = 0.05-0.3 mm- '.

For the airtight connection of the front plate 6 to the tubular piston 5, both parts can be made with the soldering alloy 89 are coated, the metal ring 83 on the upper end face coated with the soldering alloy 89 of the tubular piston 5 and also with the soldering

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ring 83 is placed (see. Fig. 7). Then in an inert gas is introduced into the tubular flask 5. After that, it is made of ceramic or the like The press plate 75 is placed on the front plate 6 and then through the press 27 via the steel ball 26 applied to the pressure F of preferably 20 to 200 bar. The steel ball 26 is used for uniform Distribution of the pressure on the sealing surface. If the pressure is too low, the result is a poor airtight one Completion, while too high a pressure can damage the tube piston 5. Afterward the two tabs 83a and 83 £> of the metal ring 83 are connected to electrodes 97 and 98, respectively, which are traversed by current, so that the soldering alloys 89 are melted and thereby the Tubular piston 5 is connected to the front plate 6 to produce an airtight seal.

Optionally, both surfaces of the metal ring 83 can be coated with solder alloy, while the The front plate 6 and the tubular piston 5 have not received any soldering metal coating.

In the exemplary embodiments described, the hermetic sealing was carried out in each case under an inert gas atmosphere. However, it is also possible to make the airtight seal without introducing an inert gas to manufacture.

The solder alloy used is cheap, and so is the solder alloy ring is easy to manufacture while ensuring excellent joint strength. In the image pickup tube, deterioration of the photoconductive layer is successful Gas expulsion prevents the ring-shaped signal electrode is not absolutely necessary. In the previous image pick-up tube, metallic indium is distributed during the connection process via the front panel, while the method according to the invention The soldering alloy used only spreads or spreads a little.

For this purpose 3 sheets of drawings

60

65

Claims (1)

Patent claims: 1. A method for the vacuum-tight connection of a front plate (6) of an image pickup tube, provided on its inside with a charge storage plate (10), to the open end of a tube piston (5), the other end of which is closed, in which the connection between the front plate (6) and the tube piston (5) is produced in such a way that after coating at least the peripheral edge of the inner surface of the front plate (6) and / or the open tube piston end with a soldering alloy (89), which mainly contains Pb, the soldering alloy is heated under pressure, characterized that the soldering alloy (89) also mainly contains Sn and a small amount of Sb and Zn and is provided between the inner surface peripheral edge of the face plate (6) and the open end of the tubular piston (5) with interposition of a multi-lobed (83a, 83b) Metal ring (83) is introduced, the inner diameter of which corresponds essentially to the opening diameter of the tubular piston (5), and that the soldering indium 2 machined so that it is shown in FIG. 1B receives an intact, oxide-free surface 2a of arcuate cross-section and the bead is given a predetermined volume, whereupon the ring-shaped signal electrode 1 with this indium bead is inserted. Immediately thereafter, a front plate 6 is attached to the indium bead by cold pressing in the manner shown in FIG. However, this üichtverfahren requires a high degree of finishing for the end face of the tubular piston 5 and the sealing surface of the front plate 6, because even the smallest scratches on these parts significantly worsen the reliability of the Abis seal. Metallic indium, however, has poor moisture resistance, so that it decomposes quickly under high temperature and high humidity. be coated. To facilitate the quick processing by z. B. Turning the signal electrode 1 must be made of stainless steel or chrome-plated