US1893573A - Light sensitive tube - Google Patents

Description

Jan. 10, V, K zwO LIGHT SENSITIVE TUBE Filed March 5. 1950 INVENTOR Vladimir K. Zwarykin ATTORNEY Patented Jan. 10, 1933 UNITED STATES PATENT OFFICE 4 HOUSE ELECTRIC A; IANUFACTURING COMPANY, A CORPORATION OF PENNSW VAN IA LIGHT smsrrrvn roan Application filed Kai-oh 5,

This invention relates to a light sensitive device and especially to a composite photo tube device.

' An object of the invention is to provide a composite light sensitive device capable of replacing a plurality of light sensitive devices.

Another object is to provide a more uniform structure of light sensitive devices where a plurality of light sensitive elements are required and also to diminish the capacity and leakage in the connecting leads to these elements.

In certain systems, it is necessary to employ a plurality of light sensitive surfaces in order to cover more than one spot on a surface at the same time. Such a system maybe, for example, that described in my copen mg application, Serial No. 199,392, for inspection devices, filed June 16, 1927. It has hitherto been the custom in such a system to employ a plurality of individual photo tubes. Unless such photo tubes were purchased from a very reliable and careful manufacturer, such tubes were not apt to be uniform in. their characteristics. Furthermore, the plurality of connecting leads to the various tubes were apt to produce both a large capacity and also a leakage in the connecting leads. Accordingly, it is an object of my invention to provide a composite light sensitive device or hoto tube that shall have a plurality of ight sensitive surfaces insulated from one another to replace the plurality of individual photo tubes heretofore used. In forming such a device, the individual surfaces may be made uniform within the device and the ca- 1830. Serial No. 433,288.

velope or container 10 having at one end the glass seal or press 11. From this glass seal or press 11 extends a pro'ection or supporting element preferably also of glass 12 extending for a considerable length of the tube. This g as projection 12 has preferably a plurality of linearly extending sockets 13 and 14 which in the preferred from are alternately spaced or staggered on each side of the glass projection 12.

A plurality of light sensitive surfaces are preferably supported from the sockets in the manner disclosed in the drawing to keep the surfaces in place and insulated from each other preferably. A supporting wire 15 is sealed into each glass socket and extends downward and is then bent at right angles parallel to the original socket, and is then secured in any preferred manner to the back of the light sensitive surface or electrode 16. It is preferred to have this light sensitive surface or electrode 16 in the shape of a slight- 1y obtuse angle as disclosed in the drawing. It is also preferred to have the upper part of the upper leg of this electrode supported from a socket on each side of the glass projection 12. A plurality of these electrodes 16 of any number desired may be supported along the glass projection 12 by means of the sockets and wires extending along the glass projection. It will be noted that the glass 'suplport 12 insulates the electrodes from one anot are spaced slightly from one another.

A connection 20 extends into the tube at the place 21 and is connected to an electrode 22 that preferably acts only as an anode. Another connection 23 preferably passes through the press 11 and extends to the farther end 24 of the glass projection 12. This connection 23 is preferably connected to the last light sensitive electrode b the connection 25. For simplicity in manu acture, a disc 26 is preferably fastened to the end of the glass projection and has on it one or more amounts of caesium 27.

A preferred method of making the electrodes sensitive to light is as follows. One surface of the electrode is coated with silver. This surface, of course, is the inner one with er and furthermore the electrodes one leg slantingly facing the side of the tube.

\ This surface is oxidized, preferably by introducing a small amount of oxygen to the tube and placing an electrode connected to a high frequency current along the surfaces to discharge evenly thereto. This oxygen and electrode are then removed and the caesium is then flashed in any well known manner, so that the caesium will deposit upon the silver oxide surface of the electrodes. The tube is scaled up. The first electrode 22 does not have to be coated as it is connected to the positive terminal 20 of the tube andacts merely as an anode.

The tube is formed, therefore, with a plu rality of electrodes spaced linearly slig tly from one another and also insulated from one another. If light is directed upon the caesium surface 17 of these electrodes, it will cause the caesium to be activated, so that a current applied across the exterior connection 20, 23 of the tube will pass through the tube provided all the tubes are illuminated. The caesium will send off electrons to the back or uncoated surface 18 of the adjacent electrode with the result that the current will pass from the back of one electrode acting as an anode to the caesium coated surface of the adjacent electrode acting as a cathode. In other words, each electrode acts as a cathode on its light sensitive surface and as an anode on its uncoated surface. Accordingly, a current source connected to the connections 20 and 23 will enter the first electrode 22 and pass from the back or anode, of said electrode to the light sensitive surface of the next electrode, provided such an electrode is illumined or made sensitive. The extension of one leg of the electrodes towards the adjacent inner surface of the tube prevents the electrons from skipping by any electrode and going to the next electrode.

If any one of these electrodes, however, is not illumined or made sensitive, it will not pass electrons from its light sensitive surface to the adjacent electrode and, accordingly, the conducting path through the tube will be broken and the entire tube will he non-conducting. In other words, the failure of any electrode to be conducting will make the entire tube non-conducting. The first electrode.

22 however is not a light sensitive electrode due to its position in the series and accordingly any description of the other electrodes is not intended to apply to electrode 22 which is only an anode.

This type of device is of special advantage in systems like my prior application hitherto referred to, Serial No. 199,392, in which the imperfection at any place in a surface requires such surface to be automatically removed from the manufacturing process. The means for removing such a surface may be such as that described in my copending application just referred to or may be of any other arrangement, as the specific means in connection with the tube just described is not within the scope of this invention.

Accordingly, there has been described a composite light sensitive device or photo tube containing a plurality of light sensitive surfaces that will replace the lurality of individual photo tubes hereto ore used in various systems. Such a composite photo tube can be formed with more uniform light sensitive surfaces and will also reduce the capacity and leakage due to the multiplicity of connecting leads in systems having a plurality of individual photo tubes.

Although I have shown and described certain specific embodiments of my invention, I am fully aware that any modifications thereof are possible. My invention therefore, is not to be restricted except insofar as is necessitated by the prior art and by the spirit of the appended claims.

I claim as my invention:

1. A light sensitive device comprising an evacuated container having a series of aligned elements and an anode therein, each of said elements, having an anode surface and a photo-sensitive surface.

2. A light sensitive device comprising a supporting element, a series of aligned electrodes and an anode carried thereby, each of said electrodes being insulated from the ad acent electrodes and being provided with a light sensitive layer on one side, whereby a conductive path may be established serially includlng said electrodes and the space between adjacent electrodes when the entire assembly is exposed to light.

3. light sensitive device comprising a contamer, a supporting element in said contamer, a series of light sensitive electrodes supported by said element, a connection from one only of said light sensitive electrodes to the exterior of'said container, an electrode adapted to act as an anode for at least one of said light sensitive electrodes and a connectlon from said electrode to the exterior of said container.

In testimony whereof, I have hereunto subscribed my name this 13th-day of February 1930. VLADIMIR K. ZWORYKIN.

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