Патент USA US2131192код для вставки
SePt- 27, 1933- K. SCHLESINGER 2,131,192 HIGH VACUUM TELEVISION TUBE Filed May 4, 1935 2 Sheets-Sheet 1 . Mia/M. Sept. 27, 1938. K. SCHLESINGER 2,131,192 HIGH VACUUM TELEVISION TUBE Filed May 4, 1955 2 Sheets-Sheet 2 Patented Sept. 27, 1938 2,131,192 UNITED STATES PATENT OFFICE 2,131,192 r ' HIGH VACUUM TELEVISION TUBE . Kurt Schlesinger, Berlin, Germany, assignor to Radioaktiengesellschaft D. S. Loewe, Berlin Steglitz, Germany Application May 4, 1935, Serial No, 19,817, In Germany May a, 1934 5 Claims. (Cl. 250-215) ing plate Ill possesses a considerably wider aper ture, so that the same is not touched by the directly impinging cathode ray and a local heat The present invention relates to a Braun tube for television purposes which is preferably oper ated in a highly evacuated condition, in which electro-static ?elds are employed throughout for ing of the bronze plate is prevented. In this way 5 producing and de?ecting the image point, and in the danger of subsequent discharge of gas within which all of the electrodes by means of which the ?elds are produced aregarranged within the tube, so that the tube is at once in an operable condition without further external auxiliary de 10 vices, such as coils and the like. The tube according to the invention, an embod iment of which is illustrated by way of example the tube is eliminated. in Fig. 1, may, broadly speaking from the point of view of physics, be divided into three parts: 15 ?rst, the beam condensing device (“condenser" in an optical sense) with control grid and per forated diaphragm, secondly the reproducing lens with tubular. member up to the anode, and thirdly two de?ecting condensers. 20 ‘ The indirectly heated cathode consists of a small nickel hood I, which at its front end, the diameter of which is 2 mm., is ground completely ?at and is furnished with a small recess 2 of .1 mm. only in‘ depth, which is ?lled up with a 2 highly emissive substance, for example a mixture of earth alkaline oxides, such as are well known in the art. In selecting the size of the recess 2 the size of the picture and the number of scan ning lines are to be taken into consideration; the exact calculation of the size of the emissive 3 O layer will be set forth below. The glow hood 2 is heated by means of a preferably slotted spiral 3 arranged in the interior of the hood, which may be insulated from 2 by a small insulating tube (not shown) consisting for example of mag nesia. The complete cathode is located exactly in axial position within a control cylinder 4 by the use of a cylindrical ?tting, so that the emis sive surface is exactly aligned with the tube axis. 40 The cylinder 4, in turn, is ?tted by means of two stamped collars 5 and 6 onto certain elements ‘ The aperture in the perforated diaphragm 9 onto which the cathode ray is projected with varying intensity is reproduced by an electron optical system on the screen, viz, by the electrode 10 system comprising electrodes ll, l2, l3 and It. The main purpose of tubular member I I (bronze) consists in screening the cathode ray traversing the interior thereof against external electrostatic ?elds. ' The length which this member is to be 15 given may be readily calculated from the desired scale of enlargement of the reproduction with a given constructional length of the tube (see be low). The tubular member H is linked up with a lower positive bias than the main anode l4 and 20 preferably than the diaphragm it) also. The path of the cathode ray does not undergo any electron optical refraction within the tubular member, since in accordance with the invention the diam eter of the tubular member is selected to be large as compared with the diaphragm aperture 9. It 25 is true that the applicant has been able to ascer tain de?nitely that a wide tubular member of this kind which is biased negatively in relation to the rays is ineffective in practice only as regards rays in the vicinity of the axis, i. e., the main bundle 30 of rays, whilst as regards such marginal ray as stray to an‘ appreciable extent it effects an auxiliary concentration which is very helpful for a satisfactory operation of the tube. It is pos 35 sible, for example, to completely suppress by a bias of this kind of the tubular member in rela tion to the diaphragm the known halation eifects, which otherwise will appear on the luminous screen. the whole of the tube system in itself, and car By means of an intermediate diaphragm with large aperture l2 and a short tubular extension l3 in coniunction'with the double anode l4 situ ries at a small distance from its upper end a dia . ated in front of the tubular member the cathode for example glass rods—provided for centering 45 phragm 1 having a narrow aperture, which dia phragm is disposed in close neighbourhood of the glow head I, for example at a distance of within .5 mm. therefrom. The cylinder extends beyond the grid diaphragm ‘I by a definite amount 8 (see below). ' The cathode ray proceeding from 2 and con trolled in its intensity by ‘I is preliminarily con centrated by 8 and impinges on a narrow dia phragm aperture 9 of approximately the same size as the emissive surface 2. The diaphragm plate carrying the aperture 9 consists of a com pletely outgassed metal having a high fusing point, for example molybdenum, which prefer ably is welded on to a bronze supporting plate 60 Hi to form the diaphragm proper. The support 40 ray refraction proper is produced. The peculiar 45 form of the electrodes is the result of systematic investigations of electron-optical lenses. The problem which has been solved in this respect consisted in the ?rst place in producing by elec trical design and adjustment the effect of a 50 spherically corrected lens having for the margi nal rays the same focal distance as for the cen tral rays. Secondly no refraction should be ex— erted on the electrons after leaving the main anode l4, and thirdly it should be possible to 55 provide de?ecting plates behind the anode with out the symmetry of rotation of the lens being lost. (“Behind” means: more remote from the cathode than.) The lens l2, l3, I4 as shown satis?es these re 60 2 2,181,192 quirements as ‘soon as the correct difference in potential has been adjusted between I! and i4, potential ‘of opposite phase the plate leakage re sistance 32 (not exceeding 100,000 ohms) is con it being maintained. positive. in relation ‘to, II,‘ This adjustment, which determines the degree. oi, electron optical refraction, is performed by means nected; with the second control, grid 221~oi the upper r'system‘of the twin‘. amplifier tube 20, the of a potentiometer I 6 which is connected with the‘ tapping 32', exactly to the extent‘to which the relaxation potential being reduced by means of a 6 terminal l5, and is connected between theearth 3 same has been/ampli?ed in the lower half of the potential, which is simultaneously linked up with ‘ ,tube ‘24, 25 (ampli?cation factor‘l/D). There is the diaphragm l0 and the anode ‘I4, and the po accordingly obtainedat the working resistance 33 10 tential oi the cathode. The refractive iield is ‘i of; thesec‘ond; anode 22 the desired reverse relaxa ited to the lens space (i. e., the space between the ‘ tion potential havingthe same amplitude but re electrodes producing the lens) by virtue oi‘ the 10 verse phase. This reverse potential is conducted to the second de?ecting plate It of the television v‘tube through the medium of a second coupling screened construction of the lens electrodes both , towards the front as well as towards the rear. The apertures may preferably be made not larger than condenser; this de?ecting plate being also earthed . it the largest cross-section of the electron bundle. through a leakage resistance 34 larger than 32. The spherical correction of the lens ‘is obtained 1 By means‘ofl a similar‘relaxation arrangement only ‘upon introduction of the'rear‘ intermediate likewise ‘comprising a countercadence ampli?er diaphragm i2 into the tubular‘ member.“ lithe‘ ‘1 the ‘front pair of de?ecting plates l8, i9‘ is also in reverse phase. It mustbe particu-., 20 as large as'the tubular extension it, the potential operated larly emphasized that without such‘. reverse phase levels have substantially the form of an inscribed circuit“ the problem does not appear capable of spherical surface,‘and the lens acts as a‘ spheri solution.“ The errorswhich‘ then occur, 1. e., in cally corrected one, which is not true‘ii’ the inter 20 width of this diaphragm i2 is made approximatelyj . ' the‘ case oi’ the usual single phase operation ‘are lack of sharpness at‘the, edge by variation 01' the focal distance, and a trapezoidal shape of the pic mediate diaphragm l2 is omitted. It“ may be added that the diaphragm l2 acts at ‘the same ‘25 time as a selection pupil by which those marginal ‘ ture‘.‘ These errors inthe image are‘ all avoided rays are stopped‘which diverge‘too strongly. byfreve‘rse phase operation of‘ the two de?ecting The third requirement, viz, the? independency.‘ plates.‘ ‘It is true that j‘the ‘mutual approach of oi" the symmetry of the lens ?eld from the“?e1d‘s the ‘pairs of plates, towards. ‘each other and the 80 of the de?ectingplates arranged behind the‘ anode anode should not be driven farther than to within I4, is obtained by-increasing the axial length of , two to three times the width oi‘mouth (distance 30 the anode to a certain extent by a small tube i5. between, the rear edges, directed towards the this manner the penetration of the ‘ileljizpf the 35 In‘ plates arranged behind the anode ll into ‘ e‘lens cathode, of the plates of a pair of‘ de?ecting » plates). - > 3] ‘ ?eld is greatly reduced,‘ and it is‘ in fact accom- “ Improvements in "the‘operation at the plates. plished that the stationary image point, iwhichis produced by the use oi’ a circular diaphragm 9, is may be obtained by giving them a suitable shape. an undisturbed round point. 40 , g, ‘i v ‘ It is convenient‘ to disposethem in‘a tilted posi- , ~ ., tion in relation to each other, asa certain gain in their speci?c‘ sensitivity ‘(deflection in mm. per‘ 40 . The de?ection of the cathode rays takes place by means of two ‘plates i6,‘ i‘! in the horizontal‘ direction, and ‘l8. IS in the vertical direction.’ The volt) is thereby obtained. Beyond this the sen sitivity ‘of the de?ection is, ‘with the use of a re de?ection is‘ unavoidably associated with simul,-, verse’ phase circuit, twice as great as with a. usual 45 taneous 1 disturbances in the sharpness oi’ ‘the circuit, 1, e., the anode battery potential 35,,may image point at the edge ofthe image it, as hereto fore usual, the one plate being connected with the be halt as‘great as‘ usually, which is of particular advantagein the case of short-ray high-vacuum tubes in which the; de?ecting plates require to be de?ecting voltage generator, the other plate is earthed. ‘ , ' . . ,_ approached as near as possible towards the screen. In accordance with the invention. it is possible It has been found ‘that to avoid interfering dis 50 to overcome this ‘di?iculty, which heretofore has placement of ‘the ray owing to wall charges a sil prevented the construction of tubes operating with purely electrostatic means, by, operating the two plates in reverse phase with ‘respect to each other. For this purpose there is, provided a special relaxation oscillation apparatus, which consists,‘ for example as shown, of the twin‘ ampli?er tube circuit including a twin tube 20.‘ Two independe . ' anode I 4 or diaphragm III.;, The applicant has as- , ‘ certained, ‘however, that this'silver‘coating‘ ‘re- ‘ quires to‘ ‘cover merely a part ‘of the bulb, viz, it '56 ‘requires, to extend only irom‘the anode it up to‘ the ‘front ‘plates i8, i9, which already project into interior'oi’ the bulb. Equally asimportant as ranged about a common cathode. , Simple single‘ the this screening is an outermagnetic screening oi’ ent grid-anode systems 22, 23 and“, 28 are ar 60 60 ver coating‘ 36 should be provided, which may preferably be connected with earth,i. e., with the grid systems with a reciprocalnoi ‘approximately . the tube by means 01’ an iron shield 31, which 2% incombination with a;mica disc screening . needs only to consist of ,a sheet of approximately means 26, are fully su?icient. “ The one oi’ the two’ ‘ systems, for example, the lower one, is connected 1 mm. thickness having a good ‘magnetical con directly with the relaxation condenser ‘20, which , ductivity, which, however, must be closed in annu-, lar form (welded or drawn) ,and need merely ex 65 is charged through the medium 01'. the resistance tend from the hot cathode to the‘ anode. . 21, and discharged‘ through the medium of a gas? . The shield is preferably, likewise connected with , ?lled grid-controlleddischarge device 29,01 that i earth. It isonly with the provision‘ of this shield general type. a well known representative of which. is the tube called "'I‘hyratron” (registered trade-H , that‘ it is ‘possible to operate the tube in any de 70 mark). The anode 25 of the‘ system here in ques sired position in irelationgytfo the magnetic earth tion is connected with a working resistance 20 of approximately 100,000‘ohms, and with the one ‘dc ?eeting plate I1 01' the television‘tube‘through the ‘ ?eld,‘ so thatparticular potentiometers for adjust ing the position‘ of the centre oithe image are unnecessary. ‘ or 70 ‘ lack of‘sensitivenessagainst ?eld disturb medium of a coupling condenser 3| . In order now . . 75 to obtain for the other de?ecting plate It an equal ances is favoured bythe extensive preliminary ‘ acceleration of the ray which iseil‘ected accord- 7 e 3 2,131,192 ing to the invention by the high positive potential of the diaphragm 9. Form of aperture is reproduced sharply; there fore also square or hexagonal apertures may be The light intensity and function of the whole tube is essentially determined by the path of the used. ' rays between cathode and diaphragm. The rays Current utilizationggg: m} gigg??gg :% should be suitably in?uenced in this particular Length of tubular member II approxi region, 1. e., in such manner that as far as pos sible all electrons in the ?rst place are passed through the narrow aperture, and secondly con Diameter of aperture of lens ll, l2____mm__ 7 Tubular member extension 13 _______ __mm__ 7 mately____ __ 10 tinue to move in such a narrow cone that no stop ping-of electrons occurs later neither in the lens nor in the diaphragm and that all electrons reach the screen in one de?nite image point. The bet ter the form of the bundle obtained, the more 15 sensitive the de?ection may be made, as a. bundle having a small cross section in the plate ?eld practically is not subject to disturbances even in __ mm 100 20 10 Diameter of tubular member ________ __mm__ Spacing between edge of tubular member and anode __________________________ __mm__ 7 Diameter of anode tube I5 __________ __mm__ Length of anode tube l5"; _________ __mm__ 7 7 de?ecting plate _________________ __mm__ system ______________________ __mm__6 and 15 Length of rear de?ecting plates ____ __mm__ 35 having a large cross section in the region in ques 20 tion undergoes lateral distortions in such systems. The applicant has found that the simple con Width of mouth of front de?ecting plates densing lens ‘I, 8, III as shown, which exactly cor responds in its operation with the ‘main lens l2, l3, I4, is capable of ful?lling the stated require 25 ments, but merely under the condition that the free length of the ray between cathode and dia phragm is not too small. The applicant has Distance between rear plates system and least 10 mm. This spacing is calculated in prac 30 tice by use of the simple diopter law on the basis of the required width of bundle. One may in fact obtain a survey on the conditions of ray propaga tion as in?uenced by the condensing lens by draw ing the most unfavourable rays from edge of 35 the cathode spot over the edge of the di phragm aperture. These rays must then undergo such a, refraction in the condensing lenses as to pass through the image producing lens and through the space between the de?ecting plates. 40 With a large spacing 'I/ III as stated above and the cylinder extension 8 necessary for spherically correcting the condensing lens, which extension ?lls out approximately one-half of the spacing. it is clear that the anode ?eldattracting the elec trons is rather weakened. If only for this reason alone the separate and ‘sumciently strong posi tive bias of the diaphragm I0 is essential if it is desired to obtain bright images. In particular cases it may be necessary to provide a screening 50 grid diaphragm 38 together with a particular in termediate cylinder 39, in order to be able to make the requirement for suitably guiding of the ray unobstructedly consistent with the requirement for su?‘icient anodic strength of ?eld as is neces 55 sary for producing cathode rays of great intensity. In the following it will be set forth in what manner a tube according to the invention may be dimensioned in practice. Cathode spot ___________ -..-'- _________ __mm__ .4 Maximum total emlssionn' __________ __mA__ .8 Diameter of aperture in grid diaphragm ‘I _______________________________ __mm__. 2 Diameter of the front surface of cath ode _____________________________ __mm__ 1.8 Spacing between grid and front surface of . cathode _________________________ __mm__ .5 Cylinder extension 8 _______________ __mm__ 3 Diameter of aperture in diaphragm III for 75 line picture size 17x20 ____________ __mm__ 20 screen __________________________ __mm__ 250 25 Anode potential _________________ __volts__ 2,000 Maximum power required _________ __watt__ 1 Heating 4 volts, A. C. or D. C ______ __amp__ .4 Potential of tubular member, volts variable, approx ______________________________ __ 1,500 30 Sensitivity of de?ection per volt, approx- _mm__ .5 Voltage of supply battery of relaxation oscil lation generator 35 ______________ __volts__ 8004 It is to be understood that the above data only refer to a particular form of embodiment of the tube according to the invention, to which the in vention is in no way limited. The individual parts of the system may be mounted on the base of the tube and centered in relation to each other preferably by the use of insulating supporting means, which may prefer ably consist of glass. The individual current leads are preferably all taken to a socket secured to the base of the tube. The current supply to the metallic coating 36 is preferably e?ected so as to avoid special fusing-in points by means of springs ?xed to the electrode system and con ductively connected for example with the anode. These springs may at the same time serve for 50 supporting or guiding the system within the neck of the tube. For this purpose they may be con structed for example in the form of compara tively strong, bent blade springs. A practical and convenient technical form of 55 embodiment of the tube according to the inven tion is illustrated by way of example in Fig. 2, like references being given to like parts in the two ?gures. 60 I claim: 1. A Braun tube more particularly for television purposes comprising means including a cathode disposed near one end of the tube for producing a cathode ray, an image screen disposed at the end of the tube opposite to that end near which 65 said cathode is disposed, and an electron-optical lens system for projecting the cathode ray onto said image screen in the form of a sharply de tem comprising a tubular member having its axis 70 disposed in the direction from said cathode to said screen and having a diameter which is con phragm l0 _______________________ __mm__ 7 ISO-line picture size 14x18 _______ __mm__ front plates system __________ _-_____mm__ Spacing between anode I5 and luminous ?ned image point, said electron-optical lens sys 70 Spacing between edge of cylinder and dia-' Diameter of aperture in diaphragm for 180 20 system ______________ __'_ ____ __mm__ 6 and 20 ' found that the spacing ‘l/lll must amount to at 55 10 Width of mouth of rear de?ecting plates highly sensitivev plate systems, whilst a bundle 60 15 Space between anode l5 and edge of rear , siderably larger than the diameter which the cathode ray possesses when travelling through .5’ said tubular member, an apertured disc shaped 75 .4 4 2,181,199 anode mounted perpendicularly tothe axis of . ‘r member facing said anode, anode being said tubular member, near said tubular member adapted to be supplied with a said high positive po between said tubular member and said image tential in relation to said cathode, tubular screen, and an apertured diaphragm separating member being adapted to besuppliedsaid with a po said tubular member into two parts and being tentiallpositiveiin relationv to ‘said cathode but 5 mounted near that l r ‘ ‘ edge of saidtubularv member. negative in relation to said anode.: facing said anode, said anode being adapted, to 4. A Braun tube more ‘particularly for‘televi be‘ supplied with a-high positive potential in re sion purposes comprising means including a cath lation to said cathode, said tubular member being ode disposed near one endjof the tube for pro 10 adapted to be‘supplicd with a‘noientiai pqsitive ,ducing a cathode ray, an image screen disposed 10 in relation to said cathode but negative in rela atthe end of the tube‘opposite to that end near tion to said anode. t ‘ l ‘ p , which‘said cathode is disposed, and an electron 2. A Braun tube more particularly for televi optical lens system for projecting the cathode’ ray sion purposes‘ comprising ‘means including a onto said image screen in. theform of ‘a sharply 15 cathode disposed .near one end of. the tube for defined image point, ‘ said electronvoptical ‘ lens producing ‘a cathode ray, an image screen dis? system comprising a ‘tubular’ member, having itsv 16 posed at the end of the-tube opposite to that end near which said cathode is disposed, and an axis disposed in the direction from said cathode to said screen and having a‘ diameter which is, electron-optical lens system fortmf?iécting the considerably larger thanthe diameter which the cathode my: onto said image screen‘ in the form of a sharply de?ned image point, said electron optical lens system comprising a tubular member having its axis disposed’in the direction‘ from said cathode to said screen and having a diameter , which is considerably larger‘than the diameter which the cathode ray possesses when travel ling through said tubular member, an anode mounted near said tubular member between said tubular member and said image screen, said anode comprising at its side facing said tubularmem cathode‘ ray possesses when travelling ‘through 20 said tubular member, an ‘apertured disc-shaped, anode mounted ‘perpendicularly to the axis of. said tubular member near saidtubular member ‘between said tubular memberandsaid‘jmage screen,‘ and an apertured diaphragm separating”25 said tubular member intoltwo parts‘ and being‘ mounted near that edge of said tubular member ‘ facing said, anode, both said anode and said apertured diaphragm having apertures the cross, her an apertured plate shaped portion disposed sections of ‘which are substantially equal to the 30 perpendicularly to the axis of said,‘ tubular member, said anode having a tube-like exten respective planes of said apertures, said anode being adapted‘to be. supplied with a high‘ posi sion in the direction away from said tubular member. and an apertured diaphragm‘ separat ing said tubular member into two parts and being mounted near that edge‘of said tubular‘member facing said anode, said anode beingY‘adapted to be supplied with a high positive potential in re lation to said cathode. said tubular‘member‘bee ing adapted to be supplied with apotential ‘posi tive in relationto said cathode ‘but“negative in relation to said anode. ‘ _‘ ‘ ‘ l 3. A Braun tube more particularly for televi cross-sectionswhich the cathode ray has in-the; tive potentiaiin relation to said cathode, said“ tubular member be adapted to be supplied with a potential ‘ positive in relation to said cath ode but negative in relation tosaid anode._ ‘5. A Braun tube more particularly for televi-l‘ sion purposes comprising means including‘ a oath-1 ‘ ode disposed near one end of J the tube for, pro ducing a cathode ray, an image screen disposed 401 at the end of the tube opposite to' that end near ‘ which said cathode is disposed,and an electron-l optical “ lens system for projecting'the cathode sion purposes‘comprising means for producing a‘ - ray onto said image“, screen in the form of a cathode ‘ray, means to ‘produce di?erent electric ?elds for in?uencing the cathode ray in different axially consecutive zones of the tube; an image screen disposed at one end of the tube to be hit? by the cathode ray after the cathode‘ray has passed through the mentioned’axially consecu— sharply de?ned image, point, said electron-op; this! lens system comprising; a tubular member having its axis disposed in the direction from said cathode to said screen and having ‘a diameter which ‘is considerably largerthan the diameter which the cathode ray pos‘sesseswhen traveling to through said tubular member, an‘a‘pertured disc shaped “anode mounted‘ perpendicularlyv to the tive zones, an electrode system located in a space of the Braun tube, both at the sides ‘of which space facing said screen and facing away from , axis of said tubular ‘member near said tubular 55 said screen at least one of said ?elds isi‘located, member between said tubular member and‘said said electrode ‘system comprising electrodes adapted to produce an electron-optically ‘refrac tive ?eld, and to at the same time screen. this refractive held against the ?elds at the side of 60 said electrode system facing said screen as well as at the‘side of said electrode system facing away from said screen, said electrode system 65 image screen, and an apertured diaphragm sepa rating‘ said tubular member into two parts and beingzmounted near that edge of said tubular; member facing said anode, both said anode and ‘ said apertured diaphragm having ‘apertures the‘ ,cross-sections‘of which are, substantially equal to the cross-sections which‘ the‘ ‘cathode ray has comprising ‘a tubular member having its axis di ‘ in the respective planes of ‘ said apertures, the rected towards said screen and having a diameter distance of said apertured diaphragm. from the edge of said tubular member facing said anode which is considerably larger than the diameter which the cathode ray possesses when travelling through said tubular member, an apertured disc shaped anode mounted perpendicularly to‘the being approximately equal‘to the diameter of the‘ 65 aperture in said apertured diaphragm,‘ said anode ‘ being adapted to be supplied with a high posi axis of said tubular member near said‘ tubular“ ' tive potential ‘in relation‘ to said‘ cathode, said 70 member between said tubular memberand said tubularmember being adapted to‘be supplied‘ image screen, and an apertured diaphragm sepa with a potential positive in relation to saidcath 70 rating said‘ tubular member into two parts ,and ‘ ode but negativein relation to said anode. , , , being mounted near that edge of said tubular KURT SCHLESINGER.