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Dec. 24, 1946. v Q_ P_ CHEV|GNY ETAL 2,412,965- ELECTRODE STRUCTURE Filed July 10, 1941 ` ATTORNEY ` 2,4%965 Patented Dec. 24, 1946 maar orties UNITED STATES 2,412,965 ELECTRODE STRUCTURE Georges Paul Chevigny, Kew Gardens, and Henri G. Busignies, Forest Hills, N. Y., assignors to International Standard Electric Corporation Application July 10, 1941, Serial No. 401,740 S Claims. (Cl. Z50-_158) l This invention relates to improvements in elec trodes for electron discharge devices, and in par ticular to improved deflecting electrodes for cath ode ray tubes. ' Z of the spot extending along any entire radius of the screen. It is thus possible, when desired, to return the beam spot to the center of the screen with each control Voltage impulse. How such a ñeld may be set up and its effect upon a pair of electrons may be appreciated by referring to the schematic showing of Fig. 1. deflection of a cathode ray beam. f In this drawing three relatively short sets of con Another object is to increase the sensitivity of centric conical electrodes I0, II, I2 illustrate cathode ray devices. A further object is to provide improved means 10 what sort of effect may be expected of the pro posed non-conical concentric electrode structure. for controlling the amount of deflection of a The beam of electrons I3 may have a normal cathode ray beam for given applied deflecting trajectory sweeping circularly so as to describe potentials. ' a generally circular orbit I4, I5 on the fluorescent Other objects and various further features of screen of the tube. Now the effect of a relatively novelty and invention will hereinafter be pointed positive potential on the inner electrode I0' with out or will become apparent from a reading of the respect to the corresponding outer one I0 will be following specification in conjunction with the to set up a radially inwardly extending potential drawing included herewith. In said drawing gradient in the generally annular intervening Figs. l and 2 are schematic showings illustrat~ ing principles of operation of devices according 20 space. A sudden application of this relative po tential will therefore deflect the beam a slight to the invention, and amount to make it follow a new course I6 and Figs. 3 and 4 are partly broken away and partly to strike radially inwardly to some circumferen sectionalized showings of preferred forms of the tial point on the orbit Il, I8. invention, A corresponding or similar relative potential When a cathode ray tube is employed as a 25 applied between the next set of elements II, Il’ device for indicating some quantity such as a may have a like deiiecting effect upon the beam, phase angle, it is customary to set up a circular It is an object of the invention to provide irn proved means for controlling the magnitude of sweep of the ray by means of quadrature cur rents applied to the deflection plates and to mod ulate this sweep radially with a control Voltage 3 proportional to the quantity in question. Such a control voltage may be applied to various elec trodes, and as a rule it is applied between a pair causing redeflection; and the simultaneous appli cation of such potentials to elements I0, I0', I I, I I' may cause further deflection of the beam so as to strike orbit I9 peripherally. By applying addi tionally a strong enough potential between ele ' ments l2, i2', it appears clear that the beam may be caused to extend to the center of the screen, flecting plates and the screen. These concen- i Ol or even further, if so desired. While the above described electrode arrange tric electrodes may be of generally conical form ment may seem feasible, we vconsider it far too and are considered undesirable because they per complex to be practical and, accordingly, prefer mit only a very limited degree of radial modu~ a more unitary construction, as shown in Fig. 2. lation of the beam, and this to such an extent In the form shown, the outer electrode 20 of the that it is not possible to form a spot near the structure is of generally conical form. A gener center of the tube. ally barrel-shaped concentric inner electrode ZI It is well known that the extent of radial de seems to be preferable as it will permit almost any flection of a cathode ray depends upon the poten degree of radial deflection that may be desired. tial gradient transverse to the beam and upon of concentric electrodes disposed between the de the distance that the beam must traverse through a field having this gradient. With the known forms of concentric conical electrodes, both elec trodes must be relatively closely spaced in order to maintain a uniform control field therebetween. As a result it is only possible to obtain relatively limited radial deflections. We have found that, by varying the shape of these concentric electrodes whereby a barrel shaped path is prescribed for the electron'beam, it will be possible to provide for radial deflection Furthermore, if desired an electronéintercepting disc-shaped plate electrode 22 may be provided, and this electrode may serve to limit the degree of radial deiiection. In the form shown, electrode 2i intercepts all electrons that are deflected so much that they otherwise would form images on the fluorescent screen on both sides of the center of the screen. . The embodiment just describedmay ñnd par ticular application in radiogoniometric systems in which it is desired to obtain a veryv clear an-- 2,412,965 3 4 gular indication upon a cathode ray tube screen. A circular sweep will continuously rotate the beam about an outer orbit 23; and, if angular indication impulse energy is applied between members 2| and 2|), a sharply defined radial in dication may be obtained. In other applications it may be desirable to show two angular indica tionsv simultaneously on the screen. radial deflection structure 24', 26’. 'I'he mag netic deñection means for one axial sense is shown schematically to comprise a pair of coils 3l), 3|. For purposes of clarity the other pair of coils for deflection, say, in a sense perpen dicular to that of coils 39, 3|, is omitted from the drawing. It is clear that by providing mag In such a netic means for generating the circular sweeping energy, it is possible to arrange this circular de members 20 and 2| to a mean biasing gradient, 10 flection to take place at substantially the same a de?lecting potential in one polarity sense could axial position as the radial deflection, due to serve to produce outward radial deflection mo members 24', 2t’. This arrangement is consid mentarily, and a deflecting potential in the op ered preferable inasmuch as members 24', 26' posite polarity sense could serve to produce an may extend into close proximity with the electron inward momentary deñection. Thus, two simul 15 gun and circular sweeping may be performed taneous indications could be obtained with ut« simultaneously with radial deflection. most clarity on the screen; and there could be no Fig. 4 additionally illustrates a preferred means case, by properly adjusting the potential between confusion as to the identity of each, inasmuch or manner of supporting our novel electrode as each indication would extend radially in an structure. opposite sense with respect to the other. As indicated above, certain features of the in vention relate to electrode means whereby effec tlve cathode ray tube magniñcation may be in Since electrons pass within member 25S', this electrode may be supported in a conven tional manner by a relatively rigid lead in mem ber 32. Appropriate support for the inner elec trode 2è’ presents more of a problem, but this creased or decreased as desired. It is thus con may `be accomplished by means of a rigid lead-in templated that electrode means may be made to line 33, sealed to the center of the bulb or screen adapt the applied signal indications to a showing Y end 34 of the tube. In order not to have poten utilizing the entire cathode ray screen to best tials impressed on line 33 in any way interfere advantage. - To this end, concentric electrodes with the passage of electrons as controlled by analogous to those above discussed in connec members 2li’ and 2&3’ and the magnetic coils, we tion with the forms of Figs. 1 and 2 may be em propose that line 33 comprise a yconcentric line, ployed. However, for maximum deflecting effl as shown clearly in the broken-away portion. ciency it is preferred that these concentric elec Control potentials may be supplied to electrode trodes be disposed as near as possible to the out~ 24’ by means of inner conductor 35. The outer let of the electron gun. ‘conductor 36 may be electrically spaced from Such an arrangement, utilizing electrostatic 35 electrode 2li’ by means of an insulating washer deflection throughout, is shown in Fig. 3. In the 3l', and if it is given a potential equal to sub form shown the inner member 2li of the concen stantially that of the fluorescent screen, varying tric electrode structure is of tear drop shape potentials on inner conductor 35 will have no with the pointed end directed toward the electron el-Iect upon the electron lbeam except as applied gun 25. In order to locate the concentric ele-c 40 to electrode 24’. trodes 24, 26 as close to the origin of deflection In designing electrode structures in accordance as possible the lateral or sweep circuit deflection with thev invention, it is considered preferable plates 21 are preferably of minimum size, that is, that the form of the outer electrode approximate only large enough slightly to deflect the beam so the shape of average ilight of the electron beam. as to avoid collision with the inner electrode 2d. . Thus, in Fig. 2, outer electrode 2li is substan It will be recalled by analogy of the form of elec trode structure 24, 26 to those of the foregoing figures, that its function will be of a biasing na ture, determining in effect a magniñcation or diminution of deiiections originating at the plates 21. It is lbelieved that, since deflection plates 21 are so small, their accuracy of control may not be as great as desired. In this case, we propose tially frusto-‘conicaL the electrode structure be ing spaced substantially from the electron gun or origin of deñection (not shown); and in Fig. 4 electrode 26’ is of the form of a generally inverse hyper-bola or parabola of revolution, since it is disposed near the origin of deiiection. Although the invention has been described in particular detail in connection with the preferred forms illustrated, it is to be understood as not the use of an additional set of relatively large limited merely thereto. plates 23 disposed in the same electrical sense or phase relation as plates 21, whereby a more strict What is claimed is: and uniform control of sweeping may be assured. Although this additional set of plates 28 seems to us at present to have particular application in cooperation with set 21 for generating a circular sweep, it is clear that plates 28 may be energized Wholly independent of plates 21 and employed for other purposes. In another` form of the invention it is possible to eliminate any need for two sets of deflecting plates, as in the case of Fig. 3, and at the saine time to maintain as high eñ‘lciency and accuracy of the sweeping operation. This alternate form is shown in Fig. 4 in which the arrangement of elements is substantially that of Fig. 3 with the exception that magnetic means are used for de flection rather than electrostatic means. The tube of Fig. 4f thus comprises within an evacuated envelope 29, an electron gun 25’ anda concentricl 1. In a cathode ray device, an electron gun, lateral deñection means, a iluorescent screen, and concentric electrostatic deflection means for radial deflection, said last-mentioned means comprising an inner generally cylindrical mem ber and an outer generally cylindrical member, said members diverging progressively with re spect to each other toward said fluorescent screen. 2. In a cathode ray device, an electron gun, lateral deflection means, a iiuorescent screen, and concentric electrostatic deflection means for radial deiiection, said last-mentioned means com prising inner generally cylindrical electrode means and outer generally cylindrical electrode means, said inner electrode means and said outer electrode means diverging progressively with re spect to each other toward said fluorescent screen. 2,412,965 5 6 3. A cathode ray device according to claim 1, `6. A cathode ray device according to claim 1, further comprising a disc-shaped target electrode in Which said inner member is of generally coni cal form having an apex in proximity to said electron gun. 4. A cathode ray device according to claim 1, in Which said lateral deflection means comprises coil means disposed about said device at sub stantially the same axial location as said concen -tric deflection means. 5. In a cathode ray device having a generally between said concentric means and said ñuores cent screen, said target electrode being coaxially disposed with respect to said concentric means. '7. In a cathode ray device, an electron gun, a ñrst set of lateral deflection plates, a concentric electrode structure concentric with said gun and cylindrical electrode disposed coaXially of the de more remote from said gun than said first set of plates, and a second set of lateral deñection plates more remote from said gun than said con vice, a support for said electrode comprising a centric structure, relatively rigid lead-in secured to the center of 8. A cathode ray device according to claim 'I in which said first and said second sets of deflection plates are similar in number and are connected in the same electrical phase relation. one end of said device and to said electrode, said lead-in including a coaxial line having an inner conductor and an outer conductor, said inner conductor being conductively associated with said electrode, and said outer conductor being in sulated from said electrode and providing a con 20 ducting shield for said inner conductor. , HENRI G. BUSIGNIES. GEORGES PAUL CHEVIGN'Y.