US2239407A - Electron beam tube - Google Patents

Description

April 22, 941. H, M. WAGNER 2,239,407

ELECTRON BEAM TUBE I Filed Aug. so, 1938 2 Sheets-Sheet 1 INVENTOR. HERBERT M. WAGNER ATTORNEY.

April 22,1941; H. M. WAGNER ,v 2,239,407

' ELECTRON BEAM TUBE Filed Aug.. 30 1938 2 Sheets-Sheet 2 I NV EN TOR.

HERBERT M. WAGNER ATTORNEY.

Patented Apr. 212, 19%

states I Ei hth? EILEUEIBON BEAM TUBE Herbert llii. Wagner, Keamy, N. lit, assignor, by

means assignments, to Radio tilorporation of America, York, N. Y a corporation of Delaware Application August so, was, Seriall No. 22mm (on. 25il-27.5)

type particularly suitable for measuring ouan-.

titles including the phase angular displacement between electric oscillations, current, voltage, power and for other purposes.

Another object of my invention is to provide such a device in which the output current can be used to maintain some specific condition governed by phase angular displacement.

In its simple form an electron discharge device made according to my invention includes a cathod for supplying electrons, means for forming the electrons into a beam, an output electrode, and positioned between the cathode and the output electrode an electrode having an aperture through which the beam is normally directed. On each side of the aperturecl electrode are positioned deflecting electrodes on opposite sides of the beam. 'Each pair of deflecting electrodes is connected to a difierent source oi voltage whereby the phase angle difierence may be measured. The second pair of deflecting electrodes between the apertured electrode and the output electrode can afiect the beam only while i it passes through the aperture in the apertured electrode and if both voltages are in phase the beam will strike the output electrode at a point directly opposite the aperture. lit the voltages applied to the deflecting electrodes are out of phase the degree to which the beam is deflected by the second pair of deflecting electrodes may be used to measure the phase angle difference between the two applied voltages, the beam striking' the output electrode to the right or left of the mid or normal point of contact of the beam with the output electrode.

The novel features which I believe to be charecteristic of my invention are set forth with particularity in the appended claims, but the invention itself will best be understood by reference to the following description taken in connection with the accompanying drawings in which Figure l is a schematic diagram and associated circuit of an electron discharge device made according tomy invention, Figure 2 is a transverse section of another form of election discharge device made according to my invention, Figures 3 and l are still further modifications of electron discharge devices and their associated circuits made according to my invention.

Referring to Figure 1 an electron discharge device made according to my invention includes an elongated evacuated envelope it, having positioned at one end a cathode M which. maybe electrically connected to a shield 01' focusing electrode H2. The beam is directed to an output electrode l'l positioned at the other end of the envelope. For the purpose of focusing the electrons from the cathode it into a narrow beam. there is provided a pair of rods it positioned on opposite sides of the beam and have applied to them a low positive potential. A first pair of deflecting electrodes in the form of rods It are positioned between the cathode H and the apertured electrode 55. An alternating voltage applied to these electrodes causes the beam to be deflected so that the beam either strikes the surface of the elec trode 55 or passes through the aperture provided in this electrode. Between the apertured electrode l5 and output electrode H is a second pair of deflecting electrodes in the form oi plates it to which a second alternating voltage may be applied. These electrodes aiiect the beam of electrons only between the apertured electrode to and the output electrode ii, the amount of deilection of the beam being dependent upon the difference in phase of the voltage applied to the plates it and the rods it. The input voltage to the rods it is introduced by means of the cou pling transformer ill which may be connected to one input and the other alternating voltage applied to the deflecting plates i is applied through the coupling transformer it connected to another input. The voltage to the various electrodes is applied from a source of voltage it, the apertured electrode 55 and anode i'l being maintained at the higher positive potentials. The deflecting plates 36 are maintained at a higher biasing potential than the deflecting rods it. To limit the beam deflection and loading of the input circuit when either of the deflecting rods it swings highly positive so that it draws current, limiting resistors it may be inserted as well as limiting resistor it. One or the other could be used alone. On drawing current a drop occurs across the resistors dropping the voltage on the deflecting rods and reducing the beam deiiection and current to the rods. The same arifl'gngement could be used with deflecting plates In operation a narrow beamof electrons from the cathode it receives a double deflection; first, back and forth about the slot or aperture in the electrode l5 and 'a second deflection after it emerges through the aperture into the region beyond. The first deflection may be caused by a voltage V1 sin wt impressed between the rods H by the input coupling transformer l1" and the second deflection may be caused by another voltage V2 sin (wt-) between the deflecting plates it, the second voltage between the two plates differing in phase from the first voltage between the two rods Hi by an angle 0. The electrodes 56 are active in deflecting the beam only part of the time, that is when the electrons pass through the aperture in the region containing the electrode l6. This instant of time occurs when V1 sin mt is equal to zero and is of a short duration depending upon the width of the aperture in the electrode I and the narrowness of the beam. At this instant a voltage 1*: V2 sin c is efiective in deflecting the beam in the region beyond the slotted electrode l5 so that the beam will arrive at electrode l? in either or" two positions to the right or to the left of the center line indicated by the dotdash line in Figure 1, except when 0 equals zero, zero phase angle between voltages, the beam is in the center. Thus the point of contact of the electron beam and hence the amount of deflection of the beam is a function of V2 sin 0 and serves as a measure of this quantity. The electrode I! may be in the form of a translucent or transparent base coated with fluorescent material so that it can be used for indicating purposes or electrode il can be so constructed that the output could be used for controlling different operations oi electrical devices in accordance with the amount of deflection of the beam.

While the electron discharge device made according to my invention is shown in Figure 1 as a single beam device, it may be constructed to provide a plurality of beams as shown in Figure 2. The cathode 2| is coaxial and concentric with the anode or output electrode 22. Disposed around the cathode 2| are the beam forming rods 23 which in this particular case form the electron emission from cathode 2| into four beams. The pairs of deflecting electrodes 28 in the form of rods are positioned between beam forming rods 23 and the apertured electrode 25 having four apertures through which the electron beams may be focused on to the output electrode 22. Positioned between the electrode 25 and the out put electrod 22 are the deflecting plates 21, which correspond in function to the deflecting plates ii of Figure 1. The tube functions in the manner as the tube shown in Figure 1.

In Figure 3 I show a modification or the construction of an electron discharge device as shown in Figure 1, particularly suitable for utilizing the output current for maintaining some specific condition governed by phase angle. The envelope 30 contains the cathode 3| and anode 32, as in Figure 1. The shield and beam forming electrode 33 and beam forming rods 34 govcm the formation of a narrow beam of electrons from the cathode, the electrode 33 serving to utilize the emission to the maximum. A first pair of deflecting rods 35 are positioned between the beam forming rods 34 and a first apertured electrode 36. A second pair of deflectin electrodes in the form of plates 31 are positioned beapertured electrode 36 is just wide enough to h allow all the electrons in the beam to pass through it to the output anode 32 at zero phase angle. As the phase angle differs from zero the current to the anode 32 decreases while the current to the second output electrode 38 increases by substantially the same amount. These two electrodes are connected to separate output transformers 39 and 40, the input voltages to the deflecting electrodes being introduced by means of coupling transformers 4i and 42.

in addition to subjecting the electron stream 'to the influence of two alternating voltages of the same frequency as deflecting agencies, I may also subject the beamto multiple deflections by alternating agencies of the same or different Irequencles, especially when the frequencies are of the ratio of integers. An example of suchan arrangement is shown in Figure 4 where a third set. of deflecting electrodes is included. With such an arrangement the operation becomes more complicated than in the cases described above. Thus in the-arrangement shown in Figure l, the beam could be made to strike the output anode in six distinct positions merely by using a voltage on the first deflecting electrodes Id of three times the frequencies applied to the electrodes 98. By modulation of the current in the electron stream the use of multiple deflections with on or more slits in each slotted electrode per electron beam and the staggering of the slots and the amplification of voltages of different frequencies and phase to the deflector electrodes, the combination and permutations are numerous. Applications which might suggest themselves are means for remote control by carrier current or radio waves of such things as airplanes steered from the ground and thelike. There is also the possibility of secrecy-in communication. I

In the electron discharge device shown in Figure 4 the envelope 45 contains the cathode 4E, output anode 41, the cathode being provided with its focusing electrode 48. Positioned between the cathode 46 and anode 41 are in the'order named, beam forming rods 49, first deflecting electrodes 50, first apertured electrode 5|, second deflecting electrodes 52, second apertured electrodes 53, third deflecting electrodes 54, the 3 alternating voltages to be applied to these deflecting electrodes being introduced bymeans of coupling transformers 55. 56 and 51, the output being indicated at 59. Electrodes El and 53' could also of course be used as output electrodes. The voltage source is indicated at 58.

The properties of the electron discharge device described above which are believed to boot parture.

ticular importance are as follows: first, the electron beaml passesthrough the first aperture when the first deflecting agency is zero, therefore the magnitude of this agency has no efiect on the magnitudeof space current when it passes the aperture or on its deflection beyond the aper- This property permits the use of an alternating magnetic field as well as internal electrodes for deflecting purposes. Second, assuming a sinusoidal agency for deflection, a first phase deflection at least two or three times greater than both the aperture and beam width, and a deflection linear with voltage for not less than the beam plus the aperture width, the average current which passes through the aperture is inversely proportional to the amplitude of the sinusoidal deflection agency. This relation is independent of current density distribution of the electr n beam, space charge; beam width, its

deformation in being deflected, and the width of the slit. Third, although the number of electrons passing through the aperture is substantially independent of the factors given above, the phase angle indication is aflected by beam and aperture widths which should be small. However, there is a minimum practical limit to these widths, and I have devised means for compensation of the slight error which would otherwise remain even after widths were made as narrow as possible. My method is to apply voltages to the deflectors in proper polarity, such that in the short interval of. time that the beam passes the apertures from left to right the second deflectors tend to deflect it from right to left, keeping the beam stationary on the plate.

While I have indicated the preferred embodiments of my invention of which I am now aware and have also indicated only one specific application for which my invention may be employed, it will be apparent that my invention is by no means limited to the exact forms illustrated or the use indicated, but that many variations may be made in the particular structure used and the purpose for which it is employed without departing from the scope of my invention as set forth in the appended claims.

What I claim as new is- 1. An electron discharge device for utilizing phase angular displacement of electrical conditions in diflerent circuits and having a cathode for emitting electrons, means for forming said electrons into a beam, an output electrode for receiving said electrons, an apertured electrode positioned between said cathode and output electrode, and means on each side of said apertured electrode for deflecting'the beam of electrons in the same plane, said electron discharge device having no other deflecting means positioned between the means on each side of said apertured electrode and said output electrode.

2. An electron discharge device for utilizing phase angular displacement of electrical conditions in difierent circuits and having a cathode for emitting electrons, means for forming said electrons into a beam, an output electrode for receiving said electrons, an apertured electrode positioned between said cathode and said output electrodes, a pair of deflecting electrodes between said cathode and said apertured electrode for defleeting the. electron beam in the space between said cathode and said apertured electrode, and a second pair of deflecting electrodes positioned between said apertured electrode and said output electrode for deflecting the beam between said apertured electrode and said output electrode, said pairs of deflecting electrodes being adapted to deflect the beam in the same plane, said electron discharge device having no other deflecting electrodes positioned between said pairs of deflecting electrodes and said output electrode.

3. An electron discharge device .i'or utilizing phase angular displacement of electrical conditions in different circuits and having a straight thermionic cathode surrounded by an output electrode, a plurality of beam forming electrodes parallel to and surrounding said cathode, a cylindrical electrode coaxial with said cathode and positioned between said cathode and said output electrode and provided with a plurality of slots registering with the beam paths formed by said beam forming electrons, a plurality of pairs of deflecting electrodes positioned between said apertured electrode and said cathode, and a plurality of pairs of deflecting electrodes positioned between said apertured electrode and said output electrode, all of said deflecting electrodes being adapted to deflect the beam in the same plane, said electron discharge device having no other deflecting electrodes positioned between said pairs of deflecting electrodes and the output electrode.

4. An electron discharge device for utilizing phase angular displacement of electrical conditions in different circuits and having a cathode for emitting electrons. means for forming said electrons into a beam, an output electrode for receiving said electrons. a p ir of apertured electrodes positioned between said cathode and said output electrode, a pair of deflecting electrodes positioned between the cathode and the first apertured electrode, and a second pair of deflecting electrodes positioned between said apertured electrodes, said deflecting electrodes being positioned parallel to each other, whereby said beam is subjected to two deflecting forces in the same plane in its passage from the cathode to the output electrode, said electron discharge device containing no other deflecting electrodes positioned between said pairs of deflecting electrodes and the output electrode.

*5. An electron discharge device for utilizing phase angular displacement of electrical conditions in diflerent circuits and comprising an elongated envelope having a cathode at one end for emitting electrons, and an output electrode at the other end for receiving electrons, means for forming the electrons into a beam comprising a pair of rod electrodes positioned adjacent the cathode, and a semicylindrical electrode on the opposite side of the cathode from said pair of rod electrodes, a pair of electrodes between said beam forming rods and said output elect'rode, and provided with aligned apertures, a first pair of deflecting electrodes positioned between the beam forming rods and the first apertured electrode and a second pair of deflecting electrodes positioned between said apertured electrodes, said deflecting electrodes being po-' sitioned parallel to each other for deflecting said beam in the same plane, said electron discharge device having no other deflecting electrodes positioned between said pairs of deflecting electrodes and the output electrode.

6. An electron discharge device for utilizing phase angular displacement of electrical conditions in diflerent circuits and comprising an elongated envelope having a cathode at one end for emitting electrons, and an output electrode I at the other end for receiving electrons, means for forming the electrons into a beam comprising a pair of rod electrodes positioned adjacent the cathode, and a semicylindrical electrode on the opposite side of the cathode from said pair of rod electrodes, 9. pair of electrodes between said beam forming rods and said output electrode, and provided with aligned apertures, a first pair of deflecting electrodes positioned between the beam forming rods and the first apertured electrode and a second pair of deflecting electrodes positioned between said apertured electrodes, and a third pair of deflecting electrodes positioned between the second apertured electrode and the output electrode, said deflecting electrodes being positioned parallel to each other for deflecting the beam in the same plane, said electron discharge device having no other deflecting electrodes positioned between said pairs of deflecting electrodes and the output electrode.

7. An electron discharge device for utilizing phase angular displacement of electrical conditions in diflerent circuits and having a cathode to said cathode, said plates being at a higher xpositive potential, said rods and plates deflecting for emitting electrons, means for forming said electrons into a beam, an output electrode for receiving said electrons, an apertured electrode positioned between said cathode and output electrode, and means on each side of said apertured electrode for deflecting the beam of electrons, said output electrode being coated with fluorescent material, said means on each side of said apertured electrode for deflecting electrons being positioned to deflect the beam in the same plane, said electron discharge device having no other deflecting means positioned between the means on each side of said apertured electrode for deflecting the beam of electrons and the output electrode. W

8. An electron discharge device for utilizing phase angular displacement of electrical conditions in different circuits and having a cathode for emitting electrons, means for forming said electrons into a beam, an output electrode for receiving said electrons, an apertured electrode positioned between said cathode and output electrode, and means including deflecting rods on one side of said apertured electrode and deflecting plates on the other side of said apertured electrode for deflecting the beam of electrons, said plates and rods being positioned parallel to each other, a source of voltage, connections from said apertured electrode and said output electrode to said source of voltage for applying a positive potential to said apertured electrode and said output electrodes with respect to said cathode, an input circuit connected to said deflecting rods and another input circuit connected to said deflecting plates, said rods and said plates being maintained at a positive potential with respect the beam in the same plane, said electron discharge device having no other deflecting electrodes positioned between said rods and plates and the output electrode.

9. An electron discharge device for utilizing phase angular displacement of electrical conditions in diflerent circuits and having a cathode for emitting electrons, means for forming said electrons into a beam, an output electrode for receiving said electrons, a pair of apertured electrodes with their apertures in alignment positioned between said cathode and said output electrode, a pair of deflecting electrodes positioned between the cathode and the first apertured electrode, and a second pair of deflecting electrodes positioned between said apertured electrodes whereby said beam is subjected to two deflecting forces in its passage from the cathode to the output electrode, said deflecting electrodes being parallel and deflecting the electron beam 7 in the same plane, a source of voltage, an output circuit connected to said output electrode and said source of voltage, and another output circuit connected between said second apertured electrode and said source of voltage and separate input circuits connected to each of said pairs of said deflecting electrodes, said deflecting electrodes and apertured electrodes being connected to said source of voltage, the voltages to which said various electrodes are biased increasing in a positive direction from said cathode to said output electrode, said electron discharge device having -no other deflecting electrodes positioned between the output electrode and said pairs of deflecting electrodes.

HERBERT M. WAGNER.

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