DE1141321B - ÍÀVidikoní type television picture pick-up tubes and method of making them - Google Patents

Description

GERMAN

PATENTAMI

INTERNATIONAL KL.

H04n; H01j

N19035 VIII a / 21a ¹

REGISTRATION DATE: OCTOBER 12, 1960

NOTICE THE REGISTRATION ANDOUTPUTE EDITORIAL: DECEMBER 20, 1962

"Vidikon" -type pick-up tubes have an electron syringe and one on top of a transparent one Window mounted screen on. The screen usually consists of a transparent conductive layer, z. B. of tin oxide, which rests on the window, while a photosensitive layer on this conductive layer Layer is applied, which e.g. consists of antimony trisulphide.

A major difficulty in making such vidicons is the fact that the screen is only may be subjected to a relatively low level of heating, making it not easy to open the window to connect with the piston. In many cases, the screen was therefore only attached after the Window and piston were fused together e.g. B. in that one brought into the piston Pill has been evaporated in vacuo. The disadvantage of this method is that it is very difficult to get one Obtain a screen with a uniform thickness.

Much better results can be achieved if, according to a further known method, the Screen is previously applied to the window, after which this window with the interposition of a ring made of indium is attached to the flask by pressure without the need to heat the attachment point is. The total pressure is about 77 kg. The disadvantage of this method is that a Pressure must be exerted on the glass piston wall, which can easily lead to breakage of the wall can. Melting with indium should be at a temperature of at least 156 ° C (Melting point of indium), whereby the screen, which is close to the fastening edge, closes would get high temperature. In addition, there could be heavy evaporation of the indium.

It turns out that the disadvantages mentioned can be avoided to a considerable extent if the piston and window of such a vidicon by means of one melted between these parts Ring made of an alloy of indium and tin are connected. Preferably there is one known per se Alloy use that contains 40 to 60 percent by weight indium, while preferably before a metal ring is attached to each of the edges to be joined together, e.g. B. by means of a type of glass, which melts more easily than the glass of the flask or window.

The temperature of the screen can thereby act as solder during the melting process Indium-tin alloy remain below 100 ° C, so that there are no adverse consequences for the screen. Soldering the window to the piston can then be used to take television pictures

of the "Vidikon" type and process for their manufacture

Applicant:

N. V. Philips' Gloeilampenfabrieken, Eindhoven (Netherlands)

Representative: Dr. rer. nat. P. Roßbach, patent attorney, Hamburg 1, Mönckebergstr. 7th

Claimed priority: Netherlands of October 16, 1959 (No. 244 440)

Edward Fokko de Haan, Leopold Heijne and Petrus Franciscus Antonius Haans,

Eindhoven (Netherlands) have been named as inventors

but can also take place in a vacuum, without a disruptive evaporation of the alloy occurring. the This is because the melting temperature and the vapor tension of the alloy are lower than those of pure indium. Working at a higher temperature ultimately guarantees better evacuation during shorter time.

The invention is explained in more detail using the exemplary embodiment shown in the drawing.

Fig. 1 shows a longitudinal section through a vidicon according to the invention;

Fig. 2 shows the individual parts of the piston before the window is connected to the piston.

The television pickup tube according to FIG. 1 consists of a cylindrical piston 1 and a window 2. An electron syringe 3 and an anode cylinder 4 are arranged in the piston. The window carries on the Inside a screen, which consists of a transparent conductive layer 6, for. B. of tin dioxide, consists on which has a photosensitive layer 7, e.g. B. from Antimony trisulphide is applied. The window 2 and the cylindrical pistons 1 are connected to one another at 5 without the screen 7 being excessively heated is.

When assembling the tube were initially rings 8, the z. B. can consist of Fernico

2C9 748/134

one side covered with a glass layer 9 which has the same composition as the glass of the bulb 1 or may have a composition with a lower melting point. The strength of the Rings 8 can be 0.5 mm. Then the rings 8 are coated on the other side with a nickel layer 10 plated. One of the rings 8 is then fused to the piston 1 with the glass layer 9, the the other ring 8 is melted onto the window 2. The window 2 is then heated to about 300 ° C, whereafter the conductive layer 6 is applied. The conductive layer 6 must be connected to the window 2 fused ring 8 are in contact. Thereafter, rings 11 are made of an indium-tin alloy fused to the nickel layers 10 with a thickness of 0.1 mm, and the electrode system can 3, 4, which is mounted on a base part 12, in which pistons 1 are melted down. Of the Screen 7 is applied separately to layer 6, preferably by vapor deposition in a vacuum.

The various parts of the tube are then placed in a bell jar, after which if necessary the electrode system is in turn degassed. Then the wall parts with the solder layers 11 brought into contact with each other, after which the rings 8 are rapidly heated by high frequency currents, so that the indium-tin alloy 11 melts and the rings 8 connects to one another in a vacuum-tight manner. It turns out that the temperature of the photosensitive Layer 7 remains below 100 ° C, so that this layer does not melt Suffers damage. Preferably, the tube 1 is placed vertically under the bell so that the window 2 can be placed on the open end and compresses the solder layers 11 due to its weight.

The electrode system 3, 4 has already been degassed beforehand and has, because it is stored in a noble gas atmosphere has been absorbed, almost no new gas. A little extra heating before Melting the soldering material or during this process is sufficient to remove any newly absorbed gas from the electrodes.

It should be evident that the treatment of the tube in the vacuum bell jar is much easier than with the known method in which a large pressure is exerted on the piston parts under the bell got to. The heavy machine parts to be used for this must also be degassed, so that high Requirements are placed on the vacuum pump.

It turns out that the vapor tension of the indium-tin alloy even during the melting process is low enough in vacuum to prevent excessive evaporation of the solder. Because only a small mass of metal needs to be heated, soldering can be done quickly, which means little Heat is dissipated to the glass of the window 2, so that the window 2 and the applied screen 6, 7 not be excessively heated. As a result of the relatively low melting temperature of the indium-tin alloy there is also practically no risk that the glass connection 9 during the soldering of the Wall parts jumps.

Although only one specific procedure is described has been, it should be evident that the amalgamation under the bell may turn into a neutral or in a noble gas atmosphere. In this case, the tube must be fitted with an exhaust tube provided so that it can be evacuated afterwards.

Claims (3)

PATENT CLAIMS: 1. TV pickup tube of the Vidikon type, characterized in that the window of the tube and the piston are connected to one another in a vacuum-tight manner with the aid of an indium-tin alloy. 2. television pickup tube according to claim 1, characterized in that the indium-tin alloy between two rings made of a metal, its coefficient of expansion is adapted to that of the flask glass. 3. A method for producing a receiving tube according to claim 1 or 2, characterized in that that the piston and the window on which the photosensitive screen is applied is to be placed under a bell jar, with the edges to be joined together with the interposition of an indium-tin alloy are applied to each other, after which after Vent the bell through the indium-tin alloy located between the wall parts High frequency heating is melted so that the piston and window are vacuum-tight connected to each other while the temperature of the screen remains below 100 ° C. Documents considered: German Auslegeschrift No. 1055 584. 1 sheet of drawings © 209 748/134 12.