US1862743A - Television - Google Patents

Description

C. D. FAHRNEY June 14, 1932..

TELEVISION Filed March l1, 1929 8 Sheets-Sheet l .ll/ffii Pfl/151115515541' June 14, 1932. c. D. FAHRNEY TELEVISION Filed March l1, 1929 8 Sheets-Sheet 2 June 14, 193.2l

C. D. FAHRNEY TELEVIS ION Filed March 11, 1929 Vlg@ 8 Sheets-Sheet 5 June 14, 1932. C, D- FAHRNEY 1,862,743

TELEVISION lFiled March. 11, 1929 s sheets-sheet 4 AT TURN au;

Jllne 14, 1932. C, D, FAHRNEY 1,862,743

TELEVI SION Filed March 1l, 1929 8 Sheets-Sheet 5 June 14, 1932. C, 4D FAHRNEY 1,862,743

TELEVISION 8 Sheets-Sheet 6 Filed March ll, 1929 HENTQR:

qfe/KM/M AT1-GENE* June 14, 1932. c. D. FAHRNEY TELEVISION Filed March 11. 1929 8 Sheets-Sheet 7 June 14, 1932. c. D. FAHRNEY 'mmasvlslonl Fiied March 11, 1929 8 Sheets-Sheet 8 vNu Patented June 14, 1932 PATENT GALLO FAHRNEY, OF CAMBRIDGE, MASSACHUSETTS TELEVISION Application filed March 11, 1929.

The principal object of the present invention is to provide a television receiving system, by means of which a relatively large picture will be reproduced by means of a comparatively small and compact scam'iing apparatus. Other objects of my invention are to provide the scanning apparatus with an improved reflector and with a more efficient picture-receiving surface than those now in use. A further object of my invention is to provide means for increasing the amount of light transmitted through the scanning apertures to the picture-receiving surface. Other objects of my invention will hereinafter appear in the detailed descriptionof the specific embodiments of my invention which I have employed to illustrate the principles thereof.

TvVith the foregoing objects in view, my invention comprises, as its salient features, two rotating surfaces of revolution, such as two concentric cones or two concentric drums, provided with co-operating light-transmitting apertures, together with means for rotating said members in the same direction at different speeds or in opposite directions. rhe lamps, the luminosity of which s varied by the incoming current, neon lamps for er:- ample, may be stationary, or may rotate with one of said surfaces of revolution. In cases where the said lamps are stationary I may employ one such lamp placed either directly behind the Window of the apparatus, or placed behind and forwardly of the same; or alternatively, since there is a limitation to the size of such lamps, I may use two neon lights placed behind and on either side of the window, together with a reflector such as a concave mirror whereby the light rays are directed to the window, with or without the interposition of a ray-concentrating means, such as a lens.

My invention contemplates also the use of a concave mirror as a picture-receiving surface.

My invention consists further in the parts and combination of parts hereinafter more fully described and set forth in the appended claims.

Various illustrative embodiments of my in- Serial No. 345,978.

vention are shown in the drawings which accompany and form a part of this specification, but it is to be understood that said drawings are merely illustrative and are not to be regarded as restrictive.

In the drawings- Figure l is a longitudinal central section of a television-receiving apparatus embodying my invention;

Fig. 2 is a similar fragmentary view of a modification;

F ig. 3 is a central longitudinal section of a television-receiving apparatus in which two lamps placed on either side of the window are employed;

Fig. at is a front view shown in Fig. 3;

Fig. 5 is a central section of a further modiication in which the lamp is placed behind and forwardly of the window;

Fig. 6 is a central section of a modification in which the lamps rotate with one of the co-operating scanning members;

Fig. 'i' is an end view of the apparatus shown in F ig. 6;

F ig. 8 is a similar view of a further modii'ication in which the relative positions of the scanning' members are reversed from those shown in Fig. l;

Fig. 9 is a development on a smaller scale of the conical scanning members shown in Fig. l;

Fig. l0 is a fragmentary view showing a development on a larger scale of the ning members shown in Fig. l;

F ll is a development of the inner scann ning member shown in Fig. 6, and

F ig. l2 is a development of the outer scanning member which co-operates therewith.

In the particular drawings selected for illustrating the principle of my invention, 5() represents one of two co-operating scanning members, shown in the present instance as a cone, although as indicated at 5l in Fig. 2, this member may be a surface of revoluanother form, such as a cylinder. he

of the apparatus tion of co-operating scanning member is a cone 52 concentric with the cone 50 in Fig. l and the cylinder or drum 53 in Fig. 2. The inner member 52 is mounted on and rotates with the shaft 54 of the motor 55, while the outer member is mounted loosely 'on said shaft and is rotated in the same direction as the inner member but at a lower speed, the gearing 56, 57, 58 and the pinion 59 meshing with the annular gear 60, which is rigidly attached to the member 50', serving to drive the latter at a lower rate of speed than the member 52.

The cone 52 is provided with a plurality ot perforations 6l which may be circular, as shown, or rectangular, as indicated in Fig. l0, and said pertorations are arranged spirally around the periphery of the cone forming in the present instance Vtour spiral convolutions, the pertorations of the several spires being arranged in four rows, each along a generatrix of said surface. In the present instance, I show forty-eight perforations forming tour spirals of twelve perforations each, although it will be understood that I do not limit myself in this manner. he arrangement of the pertorations in the cylinder 53 is identical with that above described in connection with the cone 52. The cone 50 is provided with two light-transmitting apertures, shown, inthe present instance, as the slots 62, each extending ap proximately one-half way around the periphery ot said cone in a diagonal direction and arranged to co-operate successively vwith the perforations 6l. The relative position ot the said perforations and slots is shown in F ig. 9 which is a development of the two cones 50, 52.

The preferred design is shown in Fig. lO in whichthe perforations are rectangular, preferably square, and the slots each consist of a plurality oi' contiguous rectangular sections 63, each displaced along a generatrix of the cone by a distance equal to the width of one of the periorations. A source ot light, the luminosity ot which is capable of being varied by changes in the received current, such for example as a neon light in lamp 64, is provided for transmitting light through the apertures formed when the 'pen orations and slots are in register and, as shown in Fig. l, said lamp is placed behind theA window 65 through which the transmitted light passes and impinges upon the picture-receiving surface G6, a lens 6"? being interposed between said lamp and window if desired. The lamp is supported by the adjustable bracket GS and the casing 69 in which the above described apparatus is housed may be provided with a sliding door 70.

The motor being synchronized with the motor which drives the transmitting scanning-disc the changes in luminosity of the lamp eliected by variations in the electrical energy transmitted by wire or by yradio waves will vary the light units transmitted to the picture-receiving surface 66 as the slots register successively with the perforations in the inner cone, and thereby compose the picture which was analyzed at the sending station by the scanning transmitter.

Referring to Figs. 9 and l() which lshow the relation between the slots and pertor tions in more detail than can be indicated in Fig. l, the cones 50 and 52 are assumed to be rotating in the direction oi the arrows placed above said Figs. 9 and l0, respectively, and the inner peritorated cone, in the present instance, has a speed of rotation eight times higher than that oi 'the outer slotted cone. The perforation iS has just passed beyond the window located Vin dotted lines at G5, and the perforation l is about to enter the ield oit said window. `When the perforation 4S was within the window, it was in register with the lover end of the leithand slot 62 and light was being transmitted through said perforation is and slot.

As soon as the perforation .8 passes beyond the window, the perforation l in register with the upper end of the righthand slot (i2 passes into the window and light from Va neon iainp is transmitted therethrough. As soon the perforation l passes without the .ield ot the window the perforation will pass within the saine and will be in register with the righthand slot (32, and so on until the pertorations 2, il, et, 5 and (i have swept by Vthe .\.'indo\.v, each being successively in register with a ditlerent portion of the righthand slot G2 in its pas' e thereacross, whereupon the identical aciion 'takes place with respect to the perforations T to l2, respectively, and the leithand slot G2, the aioresaid action taking place in one complete revolution et the cone 52. On the second revolution the perforations ,i3 to 24C pass across the window, sweeping `the two slots successively, and on the next two revolutions of the cone, the perliorations 25 to 3G and 3T to 4S, respectively, pass across the window and sweep the said slots.

Referring particularly to Fig. l0, it will be noted that the end portions of the two slots overlap a distance equal, approximately, to seven-eighths of the width et the window, and also that the square perforation l in the cone 52 which, as aforesaid traveis eight times .tast r than the cone 52, is in register with the upper righthand .end ot the slot G2 in its passage across the window, Athe upper boundary 7i of the righthand end ot said slot being the are oi a circle ternir-d by the intersection et said cone and a plane normal to the axis thereof. lVhen the .perforation l has ust passed without the window and the righthand end T2 ot the. siot is under the righthand boundary ot said window, the rectangular section T3, which in length is equal to one-eighth of the width oi the window, is partly within the latter, as indicated by the dotted line 73, and the pei-fon tionr2 has just come into register with the 'iii vze

lefthand end of said section, being at this instant about to enter the field of the Window as indicated by 2. y In like manner, the per foration 3 is in register With the section 74 just before it enters the field of the Window, as indicated at 3. The positions of the perforations 4, 5 and 6 as they are about to enu ter the field of the Window successively are shown at 4, 5l and 6', respectively, the said perforations being in register, respectivelyv With the sections 7 5, 76 and '.77 of the slot 62 as they successively7 pass across the Window.

It Will now be apparent that by means of the foregoing construction I am enabled to produce with a comparatively small and compact scanning apparatus, a much larger picture than could be composed by the scanning discs noiv in use. Specifically, by means of a cone 52 having its larger base twelve i nches in diameter, and provided With forty-eight holes arranged as shown, and a concentric slotted disc 50 rotating at one-eighth the speed of the perforated disc, I am. enabled to compose a three inch square picture, using perforations of approximate-ly one-sixteenth inch in diameter, Whereas if a scanning` disc were employed to produce a picture of that size, such disc Would have to be forty-eight inches in diameter and have forty-eight perforations arranged in a single spiral, each perforation being one-sixteenth inch in diameter. A standard scanning disc of the type novv generally in use in television reception and provided with forty-eight perforations arranged in a single spiral, each perforation being one-thirty-second inch in diameter, Will produce a picture only one and one-half inches square.

By means of the present invention I am enabled to use one-sixteenth inch perforations which permit the transmission of more light than the standard twenty-four inch disc apparatus with one thirty-second inch perfon rations. Manifestly, a forty-eight inch disc would be prohibitively large and while a. three inch square picture could be produced on a` twenty-four inch disc by reducing the number of perforations from forty-eight to twenty-four, the resulting picture Would lack detail.

T ie relative speeds of the two cones are determined by the number of rows of perforations and the number of slots. If it were possible to use a. single slot extending all the Way around the cone, the ratio of the speed of the perforated cone to that of the slotted cone would be four to one; in the present instance it is eight to one, and if four slots equally spaced around the cone Were used, such ratio would be sixteen to one. Thus the ratio of the speed of the perforated member to that of the slotted member is the ratio of the product of the number of rows of said perforations by the number of slots to unity. i y

lVhere the surfaces of revolution which form the (1o-operating scanning members are cones, as in Fig. l, the standard disc transmitter may be used, but Where, as in the case of Fig. 2, such surfaces of revolution are cylinders or drums, a drum transmitted must be employed. The operation of the apparatus shown in Fig. 2 is identical with that above set forth in Fig. l.

There being at present a limitation to the size of suitable lamps for use in televisionreceiving apparatus, I have devised means for increasing the amount of light transmitted through the scanning members which consists in using a plurality of lights, one or more being placed on either side of the Window, together With means for directing the light thereto.

In Figs. 3 and 4 I have illustrated a receiving system in which tivo such lights 'i' 8, 7 8 are employed, one on either side of the Window 65, although of course it is to be understood that a number of lights connected in multiple may be placed on either side of the Window. The light emanating from said lamps is directed by any suitable refiect-or such as the concave mirror 79 to the Window, and if desired a lens 8O may be interposed between said reiiector and Window. The light-receiving surface shown in Figs. 3 and 4 is a concave or magnifying mirror 8l, although it will be understood of course that the plane surface G6 shown in Fig. l may be used With the apparatus illustrated in Fig. 3, and conversely, and in general that such con cave or magnifying mirror may be employed in any of the several embodiments of my invention.

In Fig. 5 the lamp 82 is not placed directly behind the Window i5, but is located behind and forwardly of the same, and the light from said lamp is directed to the Window bv the reflector 79. L

The operation of the apparatus shown in Figs. 3, 4 and 5 will be readily understood from the foregoing detailed description of the operation of the system shown in Fig. l.

In Fig. 8, the tWo co-operating scanning members 50 and 52 are made to rotate in op` posite directions by mounting the outer member 52 torotate with the shaft 54, and by mounting the inner member 50 loosely on said shaft and connecting it therewith by the pinion 83, carried by and rotating With said sha-ft, the gear 84 and the annular gear 85 by which said inner member is carried, a sui"- able bracket 86 being provided to support the outer end of the shaft 54 and the stud 87 which carries the gear 84.

It Will be noted that the relative position of the perforated and slotted members is the reverse of that shown in Fig. l, although it vvill be understood of course that in this embodiment of my invention, as Well as that shown in Fig. l, the slotted member may be outside the perforated member. In like man- ,50 parallel thereto.

ner, it is immaterial whether the=sl0tted2member of Fig. 1 Abe disposed outside the @perforated member, as showmor inside y.the same insofar as `the actual production of the 'picture `is concerned, but under lcertain circumstances it may be preferable to Ahave said slotted member arranged inside the iperforated member when both membersrota'te in the same direction .and atdifferentspeeds.

In the case of Fig. 8,'the scanning member at the transmitting station must be `rotated oppositely to that of the scanning member used to transmit to the receiving apparatus shown in Fig. 1; :and in such case the light units will .travel across the `window .or frame from the bottom up Iinstead of ffromthe .top down. In Fig. 8 I have indicated al .lens 188 interposed between the lamp and the window.

In order `to .further increase the :sizeof the received picture and also lto make :it possible to reduce the size of the lamp without loss in transmitted light and thereby eifectza saving of electrical energy, I have devised a ireoei-v ing system in which a `plurality of lamps are carried by and rotate with `the more slowly moving of the two (2o-.operating scanning members. One embodiment ofithis system :is shown in Figs. 6 and 7 vin which the outer or more rapidly Arotating scanning member 89, herein shown as a cone, is mounted on and rotates with the shaft 54 and the inner cooperating member 90 is Iloosely mounted on said shaft and rotated `oppositely Vto that of the member 89 by the pinion 91, spur gears 92 and annular gear-98, the latter Ebeing secured to the vmember 90-in any suitablemanner. Brackets 94 attached to and rotating with the inner member 90 carry relatively small neon lamps 95, herein shown as twelve in number, .and said lamps Aareenergized by current supplied through the 'brushes 96 which make contact with the rings '97 carried by, but insulated from, the plate 98 to which the annular gear and cone 90 are secured. The cone '90 is Aprovided with a plurality `of slots 99, herein shown as twelve, one for each lamp and said slots are arrangedalong generatrices-of the cone lin the present instance, each lamp being disposed directly behind one rof said slots 4with its plate substantially The co-operating .cone 89 has a plurality of arcuate slots 91 .which are so disposed, as indicated in Fig. 11,.thatthe respective-ends of each said slot terminates at the inner and outer ends of two o'f the contiguous apertures 99. The .arrangement :is such that .when the two scanningmembers-are rotating in the direction indicated 'by fthe arrows in Figs. 11 and 12,'thespeed of rotation ofthe'outer member 89 with respect to the inner member 90 must be such :that one of the arcuate slots will vtraverse-onefof'Ethic slots 99 inthe time required-by the 'latter to move :a distance equal ,to its own width, :so that as the slots .99 ymove successively ,across means the window, reach being swept as aforesaid by=one ofthe arcuate slots, the variable light values transmitted through those portions of the respective pairs of apertures 91, 99 which are in register will pass through the window and impinge upon the mirror 65, thereby forming or composing the picture analyzed and sentout :at .the transmitting station.

It is .to be understood of .course that the analyzing apparatus at the transmitting station must conform `to the .receiving apparatus shown in Figs. v6 and 7 insofar as the (io-operating light-transmitting aperturesare concerned, that is to say, such analyzer must consist v.of twodiscs or two cones,or two other (zo-operating surfaces, provided respectively with lightftransmitting apertures conforming in shape and arrangement with those used inthe receiving system.

In the .system shown in Fig. l .in which a single stationary light is used, the perforations which ,for convenience of representation are somewhat exaggerated are in .the present instance only one forty-eighth ofthe width of the window, and even if a lamp were used having a plate as wide as the window, only one forty-eighth of its area would be eective `in transmitting light through two registering apertures. However, in the system of Fig. 6, small lamps each having a long narrow plate can .be used, `the dimensions of such fplate being substantially co-extensive with a slot 99, and in this manner the cost both of the lamps and of the current necessary to energize :the same is greatly reduced. In addition :to this advantage, a comparatively large picture may be made with a relatively small and compact apparatus.

VThe :length ofthe picture will be that of one vof the slots 99 .and the width thereof will be equal to the ydistance between two such slots, and '.thus it will be seen that by properly correlating 'the -dimensions and positions of the-slots with the rotational speeds of the respective co-operating members, a picture can `be formed larger than that possible with the apparatus of Fig. 1, other things being equal, and also that a picture equal to that made by .the apparatus of Fig. 1 can be formed by the system of Fig. 6 more economically because, as ,above explained, smaller lamps consuming less energy may be used.

Having thus described various illustrative embodiments of my invention without however limiting 'the same thereto, vwhat I claim and Vdesire to secure by Letters Patent is 1. Ina television receivingapparatus, the combination of a pair of drums one located within'theother and both .rotatable on pa-rallel axes,'the surface of one drum having a plurality of circumferentially spaced lighttransmitting apertures arranged in a plus rality ofspira'ls, and the surface ofthe other drum having ya plurality of light-transmitting slots, and-means to rotate said drums at such relative speed that said slots cooperate with successive spirals of apertures.

2. A television receiving apparatus com` prising in combination a surface of revolution provided with a plurality of rows of perforations each arranged along a generatriX of said surface, the said perforations being disposed around the said surface in such manner as to form a plurality of spirals, a co-operating concentric scanning member` provided with a plurality oit slots, and means for rotating said surfaces inv the same direction at relatively dierent speeds, the ratio of the speed of the perforated member to that of the slotted member being the ratio of the product of the number of rows of said perforations by the number of said slots to unity.

3. In a television receiving apparatus, scanning members provided with co-operating light-transmitting apertures, a window7 a lamp disposed behind said window, and a magnifying mirror for receiving the light transmitted through said apertures when in registration.

In testimony whereof, I have hereunto subscribed my name this 5th day of March, 1929.

GALLO D. FAHRNEY.

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