US2011737A - Apparatus for picture transmission - Google Patents

Description

Aug. 20, 1935. R. THUN 2,011,737

APPARATUS FOR PIC TUBE TRANSMISSION Filed May 12, 1930 2 Sheets-Sheet l .[71 venor:

Racial vb 777L411 a 'v a:

Au 2o, 1935; R. THUN 2,011,737

APPARATUS FOR PICTURE TRANSMISSION Filed May 12,1950 '2 Sheets-Sheet 2 Inventor;

Rudolph Thur:

Patented Aug. 20, 1935 APPARATUS FOR PICTURE TRANSMISSION Rudolph Thun; Schoneiche, Germany" P9 iishieeee Application May. 12, 1930, Serial No. 451,667 7 i InGermany May 18,1929 i 7 Claims. (01. 173-5) 1 ;My;invention relates to a method of andap: paratusfQ -the transmission of pictures in television, telephotography, telecinematography, va- Iiationgof the. character of the picture by electrical means and forsimilar purposes; In all such methods the pictures'to be transmitted are .split up into spots whereupon the varying light intensity'of such spots isconverted into variations of electric energy. Such variations or oscillations are transmitted to a receiver where thenare re-converted into variations of light f intensity, andtheseveral-spots are re-combined into pictures.

It is an object of myinvention to provide an improved method and apparatus for the pur- ROSBS specified with a view-to obtaining increased fineness of subdivision. In the methods and apparatus as heretofore devised, the fineness of the subdivision is uniform throughout the area of the picture,-or substantially so. However, ithas-,alsobeensllggested to increase the velocity of splitting-up toward the edges of the picture,

but ,here the variation of the splitting-up veglocityis not determined by the general character of theypicturei According to my invention, on

the otherhand, the splitting-up. velocity is rege plated during the transmission in accordance with aproperty of the picture'eiements whichin var es w th the character of the pictures. .i:-'Any d red property .cfthe pi ure elements may: :be. .Selectedas the determining factor for the splittingup velocity. For instance, the frequency of the currents transmitting the light variations maybe used as such factor.

The; problem'- may be solved in various ways, forinstance, by "arcuating relays through the medium of resonance circuits which in turn influence thesplitting-up velocity. The'means for performing my method may include a control "strip-like the stripsor. bands which are used in the ,copying of acinematograph filmsor for the shuttle controlin looms. The control strip may beare op r rep odu ti n t e p tu es to be transmitted, for 1 instan e, a copy which isxwithput the perfect definition of the original, .or a

asterccpy a In the followingfipecification I shall describe by wa o e ample en' p sa us in which the li ht intens y the sev a p c ure elements is utilized for controlling the splitting up velocity,

-.i;he,yelo city being norma11ydecreased .with the intensity of the elements. This is in accordance with the psychological function of vision as the lliotureelementswill attract the attention of the spectator in proportion: to their intensity. However; the velocity may also be increased with the intensity if the character ofthe picture renders thi'sdesirable.

In the simplest form of an apparatus for performing my invention the splitting-up velocity is regulated by a strip which is a copyof mega ture' to be transmitted. TIhe" variation off the splitting-up velocity may be impressed on a funf damental oscillation which may serve forsy'nj chronization at the same time."

' The last-mentioned method may be modified as follows: At the 're'ceiver'the intensity of [the picture generating spot remains constant butthe spot is moved at higher speed across the iiarh'er elements and at. lower speed across. the lighter elements. The apparent 'intensity'oi the picture elements is then inversely proportional 'tothe velocity of the spot, that is, it is a functionof the differential coeificient g2 dt in a diagramin which the velocity 6 of light spot is plotted against time t. i

This lash-mentioned method differs fundamentally from all known methods in which the v at o o e o ate n t e a r m 15%.!- stant per unit of time, at least for' the same picture elements, while the lightintensityof the spot is varied. In the novel method, however,

the light intensity is maintained constant, and

the variation of the ordinate per unit of time is varied. According to the fundamental idea of my invention the splitting-up velocity is a function of the properties of the picture elements,as willbeunderstood from the following consideration: In the old methods the modulation to be transmitted was a function of the variation of intensity related to the ordinate, while in my rneth-, 0d which may be termed the coordinate control, the modulation to be transmitted is the in- 't egral ofthis function. If this function is dissender and a receiver,

reser in 1 .0.1

grammatically by way of example.

In the drawings: Y V a a Fig; l is a diagram, of a systemincluding a method may 'be performed are illustrated dia- Figl2 is a diagram oia modified sender, and h Fig. 3 is a diagram of a receiver for this sender. V Referring, now, to the drawings, and first to Fig."1,::lj is fthffilm time transmitted, 2 is a feedingdrurn' on'a shaft 3, and l? isla motor or othermechanismior imparting rotation to the, drum 2. 4 is a source of light of constant intern sity; 5,-5 are condensers, and lids iamirrojr .of1a galvanometer which projects the lightraysfrom the condenser system 5,5 onto the film ,photo-electric .cell' to, which the i ht is' pro-= jected through the film i. 9 is a coilgin the cir fcuit of the cell 8, and ii! is a magnetwheeiforlg. inducing vo1tage inthe coil. H, i2 i s a wormv 'gear vby which rotation is imparted to-the wheel .iqi rQm. the sh t ner y is induced-in theooil asoften astthe film Lha'sbeenmoved f0r1the termed, th i im'ary splittingup i. Q13 isja'n m nfier' in the] circuit Qithe galvanome'ter "which controls-the mirror 6. i5 is' a filter which maybe inserted between 'theffilm I and thefcell 'n-brderZtol'compensate? the variation at; the

I filter being suitablyselectedlf I sy temitr11ens sor rriirrons, for optical mfiipensauon Ah' 'aerialipicture is generated at a .2! and ,projec ed fonto a screen 23 through the objectiveizzf.

the medium of a wheelj25 on the shaft 2A with. magnets orironpoles-ZB. 2'! is a magnet which jcooperates the wheel 25..

" Current 'fromthe system *I i -which} desired,

galvanometer; wh m-tom s, the mirror l9 and rough the coils of '{the electromagnet 21, the "'coils being =conne'cted; in parallel' or in series. fTheiwh'eel 25which acts'as a synchronous motor,

is rotated {seas to etmbme into an area thelight fromithesourc' ifi -irraccordance with the prirna'ry splittingup of the -film i at the; sender; 1 r

a Suppose that the m i 1 is" perfectly transp'ar ly-'higher}v elocity on-account of the reduced re.-

sistancaof thecell 8;. It will be understood that a I -the rdark -elements"cause slowivariationsof the current, while the light elements cause' rapid avariations of the current;

. 'At'lethe receiver; the mirror. i 9 j performs Y 1 2,011,737 e Y same movements as the mirrorii at the'lsender'. [When the picture displays a dark element at the "dth ofone row ofpicture elements, this being l fjth'e .VQH E Q QEQ Six h? ting -up element, for instance, a.Nipkow-disc, 32

Rotation is imparted to 20 through 5 Tent r fi s atespin conformity with 'bYmeansofihe-Nlpkow CM- K senderfthe light at the receiver moves slowly across the corresponding part .of the picture.

On the 'other'hand, if a light element ,is dis-- played at the sender, the. light at the receiverpicture appear' light' or dark". Ifthe" picture at the sender is a nega'tivethe picture received at the receiverwill be'a positive. a

--"Infth' example-described the degree of. fine- .ness ifld'r p edto the character of the picture 7 v only 'duringthe' secondary splitting-up, but it 'rnayalso be adapted to the primary splitting-up 7 byiinten'sifying the reaction of the induced voltage" on' ithe-gener ator so-as to appreciably iniiuenceits velocity. Preferably, in this case the rotarydiscfiiifwith its systemoi lenses is replaced byany other suitablemeans having minimumginertiatfor: instance oscillographmeansf' 1 -:'If only the risingor-descending' branch of the alternating voltageis utilized, preferably 'both branches. are arranged V at i. a different 5 average gradient', lwith the branch for 'efiecting i ,he=split ting-up having .the smaller gradient; I Referring now: to-Figs. 2; and 3, 3 his; a splitisa photo-electric. cell, and-33' is 'a tubeiunder thei'cont'rol of the cell 32.; 'The1tube33 charges a condenser fi l which bycontacting means-35 is short-cirouited as often as a row of the pic- Nipkowdisc'fl i. 'The voltage at the condenser infiuences the transmitting system 31. By the condenser-'34 theiintensity values or one row are integrated-and at the end o'feach row -'-the int'egral value is reduced to zeropso thatthe integr'ation can be'gre star tedat: the beginning:of thefne'xt row.

1 Referring now to Fig, 3, 33 1'sa tubewhich is. isampiified at Z8f10ws through the coils ofthe by the d transmlfliied .throughthe" system 31." 'l-he-anode current oi Ithistube flows through'an ohmic'resi'stancetfl 'jandta transformer coil ,40, the coils 39 amt-40 1 tubei'n turnrcontrols a'glow lainp'43 the intensity variations of which-are combined intoja picture As compared withthe-inductive resistanceof v the coil d iipthe ohmic resistance 39 *should be high,:and the grid current 'of'the tube-42 should "be small as :compared with the anode curre'rit of j the tube; 38; In"-'this'fcase Lthe curr'ent in-the coil 4i! and eonsequentl y the magnetic- ;field -of the coils 4i] anddLis proportional to the-modulation transmitted, i; e. propo'rtional to the integral of intensity related to the 'c'oordinate", orto 'the time in the case of synchronization; The-voltagi-l indii'ced inthe 'c'oil M =i'sfthe'differentiah'of field intensity related to time," and""consequently equal Y to the intensity to be. transmitted. The modulation: at the tube 42; is'therefo're' equal to the modulationefiected bythe photo-electric cell- 32 or the tube 33 so that thefglow lamp 43 in combination withp-thelNipkow' disc 44' operates.likeiany one of 7'? :the usual 1 television receivers 3 with" *intensity 'This arrangement has jaf twofold advantage as increased so that the modulation supplied by the,

tube 38 is particularly suitable for operating a 5 the convergence of the series representing the synchronizing apparatus of known type..

As compared with the methodrdescribed'with reference to Fig. 1, the novel method has the admeans described. It is also possible to adapt the "vantage that the equipments of the sender and the'receiver are the same as are used for the known methods of intensity control and only 'require completion by the additional amplifier methoddescribed only to the receiver or only I [to :the sender, sothat amplifier means havinga 20 1 case the equipment including the tube' 33, the

tubeA3 and the intermediate parts, is arranged lower range of frequency may be used. In this eitherat the sender or at the receiver and that part of the amplifier means which is undesirably influenced by the frequency, is arranged intermediate the tubes 36 ,to 38. With such equipment at the receiver side the condenser 34 may be short-circuited inaccordance wlth the movement of the Nipkow disc 44 or by any known throw-over switch, or if exceptionally high receiving amplitudes are encountered. The latter "system will particularly be adapted if a synchronous signal is transmitted at exceptionally 1 high amplitude.

- i It is understood that the apparatus described only embodies examples and that my method may .be applied to other television apparatus, in

a which, for instance, splitting-up is effected by the .Weiller mirro-r' wheel; or oscillograph means. 7 The 'method last describedto wit, renderingpracticable the adaptation of an intensifier element which is influenced by the frequency to an undesirable extent, may be used also in connec- 1 tion with the amplificationiof other-modulations,

for instance, the modulation. of sound. Generally I wish it to be understood that I do not desire to be limited to the exactdetails of construction shown and described for obvious 'modifioations will occur to a person skilled in the art. Iclaim:

1. An apparatus fortransmitting pictures at a distance by splitting-up and recombining, comprising a sender at a transmitting station, and a receiver ata receiving station, a photo-electric cell'at. the transmitting'station, meansfor con- 7 receiver, and a current generator at the transmitting station controlledlby the tone of the picture tinuouslymoving past said cell the picture to be split up, a circuit connected to said cellgmeans 7 connected to said circuit for projecting a pencil *of light through the picture onto said cell, means in 7 said circuit adapted to impart continuous movement to saidprojecting means and to be infiuenced by the conductivity of said cell under the varying intensities of light admitted to said cell, for varying the velocity of the continuous movement of said projecting means in conformity with the tone of the picture, and means at the receiving station adapted to be controlled by said regulating means for operatingv the receiver,

in synchronous relation to the sender.

2. The method of transmitting pictures over a distance which comprises-developing a light beam, scanning a picture with a continuously "moving light beam, converting the light impulses into an electrical impulse'and varying the velocity of the scanning light beam at the transmitter and receiver in'accordance with the tone value of the picture.

3. The method of transmitting pictures over a distance which comprises developing a light :beam, scanning a picture with a' continuously moving light beam, converting the light impulses into an electrical impulse and varying the velocity of the scanning light beam at the transmitter and receiver in accordance with the tone value of the picture, the electrical control of said light beam being efiected in dependency upon the value of an electrical quantity, the instantanea o-us value of which depends upon the instantaneous deflection of the beam and the first derivative with respect of the time of which is proand receiver in accordance with the tone value of the picture, the electrical control of said light beam being effected in dependency upon the value of an electrical quantity, the instantaneous value of which depends upon the instantaneous deflection of the beam and the first derivative with respect of the time of which is proportional to the tone of the picture, the values of the electrical quantity being transmitted to the receiving station and the light beam at the receiving station being controlled by the values of the quantity. 7 r

5. An apparatus for transmitting pictures at a distance by splitting-up and recombining, comprising a sender at a transmitting station, and

a receiverat'a receiving station, scanning means for splitting up the pictures at the sender, scanning means for recombining them at the receiver, means for imparting continuous movement'to said scanning means at the sender and at the receiver, and means at thetransmitting station for'splitting up the pictures at the sender, scanning means for recombining them at the receiver,

' means for imparting continuous movement to said scanning means at the sender and at the for varying the velocity of the continuous movement. of said scanning means at both transmitting and receiving stations,

'7. An apparatusfortransmitting pictures at a distance by splitting-up and recombining, comprising a sender and a receiver, scanning means for splitting up the pictures at the sender, scansaid scanning means at the sender and at the .receiver, a'photo-electric element at the transmitting station which is controlled by'the tone of the picture, and means controlled by the photo cell for varying the velocity of the continuous movementof said scanning means at the transmitter and receiver.

RUDOLPH THUN.

ning means for recombining them at the receiver,

means for imparting continuous movement to

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