US2807738A - Electronic controlling device - Google Patents

Description

Sept. 24, 1957 A. LIEB ELECTRONIC CONTROLLING DEVICE Filed July 15, 1952 FIG.

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Patented Sept. 24, 1957 2,807,738 ELEC RONIC CONTROLLING DEVICE Albert Lieb, Oberesslingen, Germany, assignor to International Standard Electric Corporation, New York,

. Y., a corporation of Delaware Application July 15, 1952, Serial No. 298,915 Claims priority, application Germany July 18, 195i 2 Claims. (Cl. 313--72) The present invention relates to electron tube arrangements of the type wherein electron beams are produced in the discharge space between cathode and anode using one or more grids. Electron tubes are already known wherein electron beams can be developed by specially shaped electrodes. The present invention has for one of its main objects the provision of an electron tube of the beam-developing kind, wherein the beam can be developed either by conventional electrodes or by specially designed electrodes, and these electrodes can also serve to shift the trajectory of the beam from one region of the discharge space to another, which regions provide respectively different characteristics, for example different amplification factors and the like.

A feature of the invention relates to an electron tube of the type having a central cathode, and a surrounding anode or anodes and with control electrodes between the cathode and anode for forming the electrons into a plurality ofbeams; said control electrodes also serving as a result of their relatively different potentials to shift the positions of thebeams to correspondingly different sections of the discharge space between cathode and anode, which sections provide different characteristics to the tube, for example different amplification factors and the like.

Another feature relates to an electron tube having a discharge space between cathode and anode with sections of different lengths, and wherein a plurality of control electrode can exert the usual beam control while at the same time serving to selectively switch the beam to a particular section of the said discharge space.

Another feature relates to an electron tube having a central elongated cathode surrounded by a plurality of control electrodes extending parallel to the length of the cathode, these electrodes serving to focus the electrons into a series of radial beams and also serving to selectively shift the trajectories of the beams in accordance with the desired output characteristics required of the tube.

Other features and advantages will appear from the ensuing descriptions. i

.In the drawing,

. Fig. 1 is a top plan sectional view of an electrode system and circuits according to the invention.

. Figs. 2 through 5 diagrammatically represent respective modified embodiments of the invention, with circuits omitted for simplicity, and

Figs. 6-9 illustrate various signal grid contours which may be used in the embodiments of the invention.

The same reference numerals designate corresponding parts throughout various figures.

In accordance with the invention, the electrode arrangement and discharge space between cathode and anode is so arranged or constructed that the respective electron beams as a result of their controlled change of position, are directed into parts of the discharge space having different discharge properties, for example different amplification factors. The said properties, or amplification powers for example, result at the different positions of the beam by the variation of the transconductance corresponding to these different positions.

The applications and advantages of the arrangements according to the invention are numerous. The invention enables the following examples of electrode systems to be used. First, the dimensions of the discharge space around the cathode and with respect to the anode, can be predetermined by special contouring of the electrodes to provide a particular form to the equi-potential or con trol field lines between the cathode and anode and by means of which the greatest possible range of linearity between anode current and the varying control grid voltage can be obtained. Furthermore, it is possible according to the control features of the invention to provide, in a simpler way, system which have double or multiple control over the cathode-to-anode current, and with the widest possible variation of control voltage characteristics. The particular illustrated forms have amongst others the following advantages; the obtaining of more definite figure of merit characteristics with smaller expenditure of energy, for example in those tubes which employ two successively arranged control grids in the path of the electron stream and whose mutual action of the grid windings introduce a pronounced effect on the discharge qualities of the tube. A system according to the invention is, for example, of importance where good electrical symmetry is desired in double control arrangements.

Fig. 1 shows in cross-sectional plan view an electrode system and essential connections according to the present invention. The cathode l is preferably axial with respect to four control electrodes 2a, 2b, 3a, 3b; another grid 4 is provided which may be used for control purposes and may be held at any suitable potential; and the anode 5 which surrounds the cathode. For particular purposes, the grid 4 should preferably have a bias potential not substantially different from the cathode potential; while the other purposes it may have a positive bias voltage approximating the anode voltage. In Fig. 1, the control electrode 2a is electrically connected to the control electrode 2b by lead 20, and the control electrode 3a is electrically connected to the control electrode 3b by lead 30; for certain purposes however, these various control electrodes can be electrically insulated from each other. For simplicity in the following description, the interconnected electrodes 2a, 217, will be referred to as control electrode 2, and the interconnected electrodes 3a, 3b, will be referred to as control electrode 3'5. 1

In accordance with the arrangement described, the control electrodes cause the electrons from the cathode 1 to be formed into four discrete electron beams, each of whose cross-sectional dimensions is mainly a function of the'voltag'e ratio applied to the two control electrodes. When the voltages on grids 2 and 3 from control source 10 are equal, then the beams are substantially separate sheet-like beams as shown in Fig. l by the dotted line areas. If the voltage ratio applied from source 10 to the two grids is varied in any suitable way, for example, by raising the voltage on grid 3 and lowering it on grid 2, then each beam will move away from electrode 2 and will be brought closer to electrode 3. The anode current between cathode and anode is now, in great part, dependent on the through-grip or field penetration of the anode voltage through grid 4 which also is related to the amplification factor of the tube. The contour of the anode varies in spacing with respect to the contour of grid 4. That is, the spacing between the anode and grid 4 is different at different points as shown in Fig. 1. This relative difference in spacing or at the various selected positions of the beams therefore provides different field penetrations of the anode, and the anode current will be 9 result in grid contours which are similar to the anode contour shown in the illustrated embodiments.

Other exemplified embodiments are possible, for example parts of the grid 4 may have a shape normal to the sectional view such as shown in Fig. 6. The grid can be manufiacturedinitially by known processes and then modified to the desired form; However, it is possible that the grids can be initially manufactured with the desired shape or contour. Similarly, it is possible to form the grids by a punching operation resulting in grids such as illustrated in Figs. 7, 8 and 9. The type of grid shown in Fig. 9 can be considered as a diaphragm. In these examples of grid shapes, the anode may have the shape such as shown in Fig. 1.

Of course, it is possible to combine with the different grid constructions, also difierent anode constructions. Furthermore, the possibility exists of using with the various grids of Figs. 6, 7, 8 and 9, an additional surrounding grid. This surrounding grid may be considered as a space charge grid and can be electrically connected to the preceding control grid or to a screen or shield located either internally or externally of the tube. It is even possible to make both grids as one unit.

A slightly modified form of the invention is shown in Fig. 2. signal grid 4 may also serve the beam shifting functions performed by the control electrodes 3a, 3b of Fig. 1. The grid 4 can be connected to any suitable bias voltage relative to the cathode. A pronounced controllability of the discharge current to the anode can thus be obtained by control grid 2, since the grid 4 sets up an electron space charge effect. To a still greater extent than in the embodiment of Fig. 1, by specially forming the anode to the shape shown in Fig. 2, a much greater control on the characteristics of the discharge current of the electron beams can be obtained.

A further embodiment is shown in Fig. 3 which illus} trates a multiple-controlled double electrode system, com prising separate anodes 5a, 5b, to which separate discharges or beams pass from the cathode 1. The beam currents to the anodes 5a, 5b, can be controlled by various voltages on the interconnected controlelectrodes 2a, 2b, in a nonsymmetrical way; while for varying voltages applied to grid 4, the control of the currents to the anodes is symmetrical.

Another embodiment with similar controllability is shown in Fig. 4. The control of the beam paths to. the anodes 5a, 5b, is asymmetrically efl-ected by separate grids 4a, 4b; and is efiected symmetrically by means of the control electrodes 2a, 2b, which can be electrically connected together.

In Fig. 2, the supporting side rods 4 and 4" of i While in the foregoing embodiments there'has been shown four control elements by means of which four beams are developed, it will be understood that the number of such control electrodes may be increased as desired to produce a corresponding increased number of beams. Thus, there are shown in Fig. 5, six control electrodes 2a, 2b, 2c, and 3a, 3b, 3c. The electrodes 2a, 2b, 20, may be electrically connected together; and the control electrodes 3a, 3b, 3c, may beelectrically connected together. In this embodiment, it'willbe noted that the anode 5 is formed with six sectors, three'of which are much deeper or'more widely spaced from the grid 4 than are the remaining sector's. V

It will be clear that different examples ofembodiments may be combined in any suitable way. Furthermore, it is clear that screen grids may be provided'in front of the anodes.

In the various embodiments, the output characteristics of the tube, for example the amplification factor or transconductance, is controlled by the shifting of the beam by the control grids and also the size of the beam in its shifted position is controlled by the particular portion of the grid aperture through which the shifting beam is passing to the anode. a

What is claimed is: a 1. An electron tube comprising an axially located cathode, a plurality of pairs of beam control electrodes' surrounding said cathode, said control electrodes being mounted in diametrically opposite pairs, means for connecting each pair of control electrodes to a source of potential to form the electrons from the cathode into respective radially extending beams located between adjacent control electrodes, an anode means surrounding said cathode, said anode having portions thereof which are more distant from the cathode than the remaining anode portions to provide different tran'sconductance values t'o the tube as the electron beams are shifted under control of said control electrodes.

2. An electron tube having an' axially located cathode,

a pair of symmetrically opposite rod-like beam control electrodes spaced from said cathode, an anode means symmetrically located With respect to the cathode and with respect to said rod-like electrodes, said anode means having discrete portions at different distances from said 7 cathode electrode, a signal grid located between said cathode and anode on the same side of thecathode as one .of said beamcontrol electrodes, said control electrodes serving to shift the electron beam from the cathode to different points on the associated anode. H

" T References Cited in the f le of this patent 1' UNITED STATES PATENTS a Feb. 23; 1937 2,071,382 Balsley 2,097,306 Rothe et al. Oct. 26, 1937 2,126,288 Schlesinger Aug. 9, 1938 2,144,085 Rothe et al. Jan. 27,1939

2,197,041 Gray Apr. 16, 1940 2,307,693 Linder ...Ian.;5, 1943 2,372,282 Kilgore Mar; 27,1945

2,529,408 Montani Nov. .7, 1950 v 2,563,197 Sziklai et a1. .Aug. 7, 1951

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