US2141415A - Multiple cathode-ray tube - Google Patents

Description

g Blah-41% OR 2%1419415 SR Dec. 27, 1938. sc smg 2,141,415

' MULTIPLE CATHODE RAY TUBE Filed June 16, 1956 Patented Dec. 27, 1938 UNITED STATES btJarCi'l llUUHl PATENT OFFICE MULTIPLE OATHODE-RAY TUBE Kurt Schlesinger, Berlin, Germany, assignor to Radioaktiengesellschaft D. S. Loewe, Berlin- Steglitz, Germany Application June 16, 1936, Serial No. 85,495 In Germany June 20, 1935 3 Claims.

The tube described in the following performs the production of a plurality of independent image points in high vacuum. The image points may be deflected completely independently of each other. They may, however, for certain purposes also be coupled with each other in certain fashion as regards the deflection. Tubes of this nature with and Without a filling of gas are already known per se. described a gas-filled tube in the application No. 49954/35 filed November 15, 1935. High-vacuum constructions of multiple-ray systems have been set forth by Knoll and are characterized in that a diaphragm provided with a plurality of apertures is reproduced by one single electronic lens.

The present tube differs fundamentally from the last-mentioned high-vacuum tube by the fact that as many lenses are provided as image points are desired. A special lens is employed for each image point. tion resides in the fact that the individual rays are completely independent of each other andpossess at all points an evenly parallel and sumciently large spacing from one another. It is accordingly unnecessary to provide elements for pre-deflecting the difierent rays. According to a further feature of the invention a special hot cathode is provided, which ensures an even light intensity of the individual image points and is freed from the influence of the end cooling.

The invention will be more fully understood from the following detailed description if it is taken in connection with the appended drawing.

Fig. 1 of which is a schematic longitudinal view, shows, as far as the present invention is concerned therewith, the parts of a cathode ray tube designed according to the invention together with certain circuit elements also designed according to a feature of the invention, whereas Fig. 2 illustrates a certain detail viewed in elevation from the cathode to the screen side.

Referring to Fig. 1, a plurality of filaments 3 are located behind a diaphragm Zprovided with three or any desired number of apertures l in a spacing which is greater than 5% of the length of the tubular member. In the present case with a length of the tubular member of 40 mm. the spacing amounts to approximately 2' mm. In viewing the diaphragm 2 from below (i. e., in the direction from the cathode to the screen 8) it appears as shown in Fig. 2. The filaments 3 are coated with oxide behind the apertures l and only there. They are suspended between resilient supports and are all heated in common, preferably in series or parallel connection, $eries connection The applicant himself has The advantage of this construephragm points I takes place by means of a mule tiple tubular member. Each aperture is situated below the axis of a tubular cylinder 4.. In front of the tubular members there is situated an anode plate 5, which in turn possesses an aperture 6 for each tube axis. Following on the anode plate 5 are deflecting systems. These are represented by the plates 1, which may all be insulated one against the other, but which for certain purposes may be connected with each other at the points I. In the latter case the tube is suitable for measurements according to the 3-voltmeter method, for example for measurements of triphase mains or also for cardiographic purposes. The rays are concentrated on the luminous screen 8. The concentration may be obtained in common for all points by means of a unitary bias of the tubular member 4 at a potentiometer 9. The diaphragm 2, in accordance with the invention, may likewise be connected with a variable tapping of the potentiometer 9. Together with a decrease of its positive bias there occurs a reduction in the diameter of the image points. It is true that at the same time the light intensity of the image points decreases. It has been found that a tube of this kind may be heated by alternating current without disturbances occurring.

The medium potential of all deflecting plates is that of the anode 5. It is possible to apply to the middle plates 2. negative potential, which may be obtained, for example, by the tapping In of the common distributing means 9. In this case the outer rays are forced outwards. The same object may naturally also be accomplished by a positive bias at the outer plates.

A modification of the system shown for television purposes may be performed without difficulty by the inclusion in each case of a grid H l l al 10 may be controlled independently of each other. It is possible, particularly when employing the push-pull principle, to perform a common transverse deflection of all rays by one pair of plates l2. Mutualinterferences of the different plates of one group and of the groups of plates in relation to each other are readily avoided by operation of the last-mentioned pair of plates l2 in reverse phase with the anode potential as medium potential. It is naturally also possible to perform the common transverse deflection by means of a pair of magnet coils, whilst the defleccomposed of part grids Ila, lib, He. The grids tion to be measured is performed electro-statical- 1y by means of the plates 1.

In a tube system of the stated kind having separate tubular reproducing members for each ray it is desirable to make the spacing between the single tube axes as great as the maximum amplitude of movement which it is desired to adjust on the screen. A particular preliminary deflection is in this case unnecessary. The rays run parallel to each other up to the screen. It is, however, also possible to incline the axes of the different ray-systems in relation to one another, whereby a larger spacing of the image points is obtained on the luminous screen likewise without deflection of the rays.

I claim:

1. In a multiple cathode ray tube comprising a plurality of sources of electron emission, a first anode structure mounted near said sources to cooperate with said sources in producing a plurality of cathode beams equal in number to said sources, and a second anode structure mounted at a comparatively large distance from said first anode structure and adapted for use as a main accelerating means: a plurality of electrically conducting tubular members equal in number to said sources mounted between said first and second anode structures to produce a plurality of electrostatic electron lenses equal in number to said sources for focusing said beams into a plurality of images equal in number to said sources, said tubular members extending substantially along the whole distance between said first and second anode structures so that they screen the beams from each other where the beams have not yet undergone their main acceleration, and thus make the beams completely independent from each other.

2. A multiple cathode ray tube comprising a plurality of incandescible filaments each having a coating on a highly electron emissive material of a small portion thereof, only, a first anode structure mounted near said incandescible filaments and having a plurality of apertures each of which is opposed to one of the coated portions of said filaments, to co-operate with said incandescible filaments and their coated portions in producing a plurality of cathode beams equal in number to said filaments, a second anode structure mounted at a comparatively large distance from said first anode structure and adapted for use as a. main accelerating means, and a plurality of electrically conducting tubular members equal in number to said filaments, mounted between said first and second anode structures to produce a plurality of electrostatic electron lenses equal in number to said filaments for focusing said beams into a plurality of images equal in number to said filaments, said tubular members extending substantially along the whole distance between said first and second anode structures so that they screen the beams from each other where the beams have not yet undergone their main acceleration, and thus make the beams completely independent from each other.

3. A multiple cathode ray tube comprising a plurality of sources of electron emission, a first anode structure mounted near said sources to co-operate with said sources in producing a plurality of cathode beams equal in number to said sources, and a second anode structure mounted at a comparatively large distance from said first anode structure and adapted for use as a main accelerating means, a plurality of electrically conducting tubular members equal in number to said sources mounted between said first and second anode structures to produce a plurality of electrostatic electron lenses equal in number to said sources for focusing said beams into a plurality of images equal in number to said sources, said tubular members extending substantially along the whole distance between said first and second anode structures so that they screen the beams from each other where the beams have not yet undergone their main acceleration, and thus make the beams completely independent from each other, an image screen mounted at the end of the tube remote from said source, deflecting means mounted between said second anode structure and said image screen for causing each of the images into which the cathode beams are focused tomove over said screen, and means for preliminarily deflecting the beams to prevent the mentioned images from interfering when moving over said image screen during operation.

KURT SCHLESINGER.

CPI

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