US2011947A - Television system - Google Patents

Description

2 Sheets-Sheet 1 irvlou. ZTRANSQ A M L. NICQLSON Filed Sept. 28, 1935 ELE E Aug 2, 1935.

' j INVENTOR 46 Alexander M Lean Niunlslm Aug. 20, 1935. A. M01. NICOLSON TELEVI S ION SYSTEM Filed Sept. 28, 1933 2 Sheets-Sheet 2 E :1. E... E

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T0 ELECTRODES INVENTOR Alaxanller M LEHIl Ninnlsun TD SREN ELECTRODES W ATTOR N EY Patented Aug. 20, 1935 Applicationsepternher 28,1933,ser air ceisic v V 3*Claims. (cine-c) V 1 I Thisinvention relates to the transmission of intelligence in the form of electrical currents characterized 'by-the'l-ightand dark intensities of ,unit areas of anohjectuor the image thereof, and

,p'artioularlyto. the; analyzationandproduction of "images, infine -graineddetail at a rate to produce the illusionof motion. 1 v 1 In the present systems of this ,art known as television, resolution orscanning is accomplished ,by vari0us methods, such as by rotatingvdiscs havingapertures;11enses or reflectors which :produce a moving spot or beam of light intermedh ate'amodulatedlight source and the screen or observer to reproduce the-image; yby cathode ray systems wherein the cathode beam ismodulated with the image currents ando made to impinge upon fluorescent material to produce the variations of the cathode ray in corresponding'light values; and bymany modifications thereof. Al-

though these types have been under develop ment for a considerable period'they'all havethe disadvantage of producing too large a unit area. 7 That is,-the grain-of the picture is coarse, so, that imuchof the detail or the objectis lost, While images of 'rnultiple'objects-are entirelyimissing in such systems' i 1 I 1;: l 3 The presentinvention accomplishes the reproduction of television images ina manner .to re.- producethe; image in all itsdetail by resolving wthe-objectinto smallerunit areas and reproducing;each oif' them in itsproper size and lightintensity relationship. In general, this is 1 accomplished bytheuuse of minute electrodes on the V 1 "order of pin points o r small balls comparablein viduallylreproducedat fixed-points in actual position land size, (thus. preventing enlargement and overlapping by variation in scanning-apparatus;

-- and light diffusion. 1 V Anobject' of the inventionis totransmit tele- .:vision images of: greaterfidelity and accuracy;

: Anotherobject of the invention'is to analyze an object andreproduce the image thereof-in detail comparable to photographs,

Anotherobjeot of the invention is to use light in theform of a, discharge on a suficiently small I "scaletdapproximate an actual photograph of f't he object being transmitted.

The invention will ofl preiully understood "from theufollowing description read in conjunction with the accompanying rldra wing's in which:

' Fig. l diagrammaticallyillustrates a transmit-g tor; embodying the invention;

' Fig. "7 is a Qdetailof thescanning sc may be in the form of electrolytic so1ution, In 4 e V is such as to aidyi'nthe-production-of :therdischarge from ele trodes-6, the is p-reduced'by a Tesla coil I :;rail system and supplied from i any propersource v,flifig.-:5 show.s a substit te arrangernentfor the scanning systemof Figs; 1, 2, 3 andA;

Fig-6;

Referring to- Figs. 1 fand ifi, in which fthe sarne numerals represent identical elements, ascanning and reproducing screen5 is composed of .a multiplicity ofpoints or small 'ballelectrodes 6 connected througha "corresponding number ,of

conductors l to probesp positioned intermediate, continuous electrode" rails gl 0, cvvhi are ,located in a magnetic field produced by winding shown in crossesection, the winding I- l ,ha ng-sa core l2.v In-Fig. 4.-.t he electr de rails, lii -w h thecon V, ductors "i leading :fromgthe prob es s trated in ,detail ,to show the ;respective positioning 1 ofthe probes which; are j placed at uniform intervals between the electrodes. Energy suriplied irom a source gldshunted-by a-rcondenser i 5 under control ofa rheostat -l| producesan electrical discharge *betweenflthe rails I11, which v The coil;;;l l issupplied. from a source 253 "undercontrolgoifa-rheostat 2] -:disclosed in myiUnited- States Patents-NQ. 1,839,-

6 J n y '5 2 -:N "b 23; June 1 sizetol thatof newspaper. p-rint, commonly.called{ 93 p j-\ c: f .thal f tone. That is, .theunitiareaswill be indis i n mm d t -i iii-9. 1 0f s i fi? trodes 8 is a gscreen 25 roundedat 26 which a mesh, suchsaszillustrated ;.in 3, or maygbe ct-sputtered metal on a glass screen or a fiatglass envelope itranslucent other words, ,thiescreen V v'oltageirom which 3 n e i dieth i m IOf- BflGl'QIY, such as-a l lo-volt alte rnatingv current supply. source is grounded at'r-2 9v thus com- 1 pleting the circuit through electrodeai; ;--It, is to he understood; of course, thattheg system may be operated without screen 25 if thewoltagepi the Tesla coil is raised tonasufficiently high value. 7 However, it .is desirable tousetaslow a voltagetas possihleior apparatus ofrthistype. and thescre'en 25 aids/in the corona discharge lfromih electrodes-fi.. s g

' Fig.6 is a planview. of a scamiing or rec v- V ingscreen in another forrnbal di isdriven andpropagated there alongbythefieId produced by the coil H carrier current: from an oscillator 40, is impressed upon a transmitter 4| connected to an antenna '42 or a carrier wire system.

In Fig. l, which is the transmitter, an aperture 30 in an opaque screen 3| defines the scanning beam which'may be aided by a lens 32 to scan an object shown in the form of an arrow.

The reflected light from the object O modulated by the light and dark intensities of the unit areas thereof, impinges upon a photoelectric device 35; The output of the device 35 is amplified in an amplifier 3 6, which feeds a modulator 31 and the primary of a transformer 38, which has its secondary in the supply circuit to the electrode rails ill.

The purpose of this feed-back or regenerative are they occur at the instants the arc passes the probes I 85 It will be thus seen that as the arc reaches a. probe thereby connecting the electrodes 6 to the Tesla coil 28 to produce a light spot, an impulse willbeprovided from 'thelamplifier 36. As the j force on the arc is proportional to the strength of thefield, the length of the arc and the current 'thereinfan increase in arc, current will increase this force. The arc, thereiore, will fallf-into a certain speed relationship with respect to the amplitude of the impulses caused by its commutation. r i

The output f-amplifier 36, after being modulated in the modulator 31, which is supplied with Referring nowparticularly to. Fig. 2, the in- [cOming impulses are received upon an antenna 45, amplified in amplifier '46, detected in a demodulator 41, amplifiedagain in an amplifier 48,'

and impressedupon 'the'supply circuit for the "electrodes Ill througha transformer 49.. There ;is

thus produceda 'variationin the intensity of the discharge'betweenthe electrodes 6 and the screen i 25, i fused, proportional to the voltage impressed on the arc discharge electrodes through the transformer 49. z is accomplished by a diminution in the resistanceof the arc path to permit a proportional amount of energy to flow to the electrodesfi, As the incoming currents are in the' form of impulses proportional to those fed back to the transmitterarc, they will have the effect;

o f keeping the receiver are at the same speed the transmitterarc if the other are control elements have valucs'approxirnatelythe same or proportional.

Referring nowto the electrode screen 5,'which is animportant feature of the invention, this 1 screencomprisesa plate of insulating material through which are'positioned. the fine point or ball electrodes 6 closely spaced, comparable to .the arrangement of the points on a half tone plate.

It is thus obviousthatla. picture having the same detail as a newspaper print, or better, maybe reproduced with this type of television scanning and Su fiicient' arc speeds have been found from development work on television: systems in which the light of the arc is employed for. the reproduc- 75 tion .of the imageor for scanning. Theplate with reproducing screen. Withthe commutating system just disclosed an extremely large number of pointsmay be commutated at the proper speed.

its electrodes may be either exposed to the open in which a Tesla coil--69 is included.

air or enclosed in an envelope below or above with a-conductor 1, which feeds-one of'the elec-.

trodes, 6 of the screen.- A common return 55 is connected to a modulator 56, fed from a'grounded oscillator. 51 which completes the screen circuit. Adetector 58 getting its signals from a receiver 59 connected to an antenna 60 completes the receiver circuit. The commutator of this figure may be substituted for theportion of the system of Fig. 2 shownwithin the dotted lines.

Referring now to'Figs. 6 and 7, in which'another embodiment of the invention is illustrated;

a system of electrode 'rails 65 have at uniform intervals projections 66 which mayterminate in small rounded portions 61; The electrodes 65 are in the form of a continuous path and are connected to a source of alternating potential The coil 63 is supplied as shown from a 110 voltalternating current-source grounded at 10. Surrounding the arc screen is a field coil 13 supplied from a source 14 under control of a rheostat 15.

.The field is illustrated as a single turn but may comprise a solenoid of the type disclosed in the above-mentioned patents or as shown in the other figures, suitably arranged for this type of arc path. Thisportion of the screen may be enclosed in a transparent envelope as described for the electrodes 6;

Positioned immediately infront of the arc path is aplatelB, which may beof glass with sputtered metal or of insulating material having piercing electrodes 19 positioned therein to form unit areas. Immediately in front of the plate 18 may be positioned a plate 16 grounded at 11 similar to the screen 25 of Fig. 3 to aid in the production of the corona discharge at the terminals of the electrodes'll. It is understood, of course, that the screen 16 may be omitted if the voltage of the Tesla coil 69 is sufficiently high to produce the desired corona effect.

This system'operates similarly to the systems of Figs. 1jand,2,'eXcept for the method of arc propagation. created between. two of the points 61 at or near In the present system the arc is the peak of the wave and is subsequently extinguished at a lower'voltage value as the volt- .age decreases, since the voltage of the Tesla coil is'made insufficient to maintain the arc'below this voltage. At the next peak the'arc is again created between one ofthe old points and the next succeeding point; The are strikes here becauseof the how of the uncombined ions be-.

tween the point of extinction and the next point of initiation by the-field produced by the winding 13. The winding 13, therefore, is not a driving field winding, as is shown in the commutating systems of Figs. 1 and 2, but is only a biasing winding-thatie, it is only required to move is intermittent and is controlled by the frequency of thes'ource 68, which may be varied at will.

The synchronizing in this system is accomplished providing an electrical discharge at the points of said electrodes, a setof electrode rails, means for'forming an are between said rails, means for propagatingsaid arc, and means for, connecting said electrodes and said-energy source through said arc path in a serial order. f

2. In a television system comprising a plurality of point electrodes positioned to form an illuminating screen of fine definition, a source of energy for said electrodes, an electrical discharge system including polarized electrodes located in a magnetic field interconnecting said first mentioned electrodes and said energy supply for connecting said energy supply to said first-mentioned the combination of- ,a plurality of electrodes arranged coordinately in an insulating medium, asource' of'energy for electrodes in a serial order, means Ior translating reflected light from said first-mentioned electrodes characterized by light and dark densities of an object into electric curr ents, and means for impressing a portionvof said currents on said 3 are electrodes ior obtaining a predetermined speed thereof.

I 3. In a television system, the combination of a plurality of electrodes arranged in aunit area pattern, a source of energy for polarizing said electrodes, a screen located adjacent said electrodes said screen having continuous electrode rails, means for creating an arc on said electrode rails, means for creating and propagating an arc along said rails, said plurality of electrodes being arranged along the path of said arc rails for imparting to said'plurality of electrodes in serial order a portion of the energy of said are to create a discharge at the terminals of said plurality of electrodes in accordance with the 20 strength of said arc.

ALEXANDER MCLEAN NICOLSON.

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