US1927900A - Facsimile transmitter - Google Patents

Description

Sept. 26, 1933. LA VERNE R. PHILPOTT 1,927,900

FACS IMILE TRANSMITTER Filed May 28, 1930 INVENTOR LaVerneEPh/YpOfiI TroRNEY visibly printed 'on the message paper, thereby Patented Sept. 26, 193. f j

mcsnunin 'rnmsistn'r'rmi 'Laverne'jPhilpott; WiIkinSBurgPaQI aSsign 'to'..Westinghouse-fElectric &- Manufacturing, 1 QEDFPmacorporation ofPennsylvania 7 My invention relates-tothe transmission of pictures, images, printed matter or: the like, wherein a beam of light is caused to traversesum} cessive elements of a -subjeot,- the resultant light variations being: subsequently translated into cor responding electric currents" for transmitting over wire or. through the. ether. More particu larly, my invention relates to improvements in' or selective.transmissionlm'ay :be possible. I Itis conceivable that under-certain conditions,

,such transmitting systems whereby either secret it might be desirable to transmit only definite.

portions or selected outlines appearing on a picture orfacsimileto be sent'to somedistant re--- ceiver; In transmitting code mes'sages-for example, it would constitute a great convenience-to the writer-of ,the message to havethe'code key eliminatingflthef necessity of havingiacode book available at'alltimes for reference and use.- It would not be desirable, however; to transmit the code key along' with the message an'd,:by-my inness methodsandconditions;

vention, Ihave made it possibleit'o' transmit the onewithout the other. 1 i This particular system of was communication would" be admirably'adapted to present day ,bu'sidditional "practical applicationsiiof my inventionreadily suggest themselves Drawings or sketches may be transmitted from coordinated T paper withoutlthenecessityof transmitting the rulings on said paper; the drawings or sketches? being received on a;clear" -whiteba'ckground, whereupon they become much 1 more legible and discernible. 1

--Wh81 it becomes'z' desirable to transmit; in secrecy, the location {of i enemy 'positions; or' the 1 like, such locations maybe. indicatedon' 'a bla'nk production obtained at the receiv ing 'endwill 'merelydisclofsea numberof check marks 'orother symbolson a blank backgroundfrom which no information can be obtained. "This may'then be 1 'so superimposed 'up'on a blank 'or dummy map, similar to the one-utilized in transmission 'as" to make understandablethe information conveyed 'by the symbols. '1

' It will be ap'parent; will open up'a wide f eldof use for facsimilereproduction systems, as it-lends itself to numerousnovel andhighlydesirable applications.

" f It is accordingly one object of my invention to jss providea method of facsimile transmission whereby it becomes possible to transmit only desired novel photo 'cell' transmitter;

lyingwithin the audio-frequency range. beam, so interrupted, is subsequently transformed into an electric: current of l the same frequency,

thereforefthat my invention facsimile transmitter-"which is color. ,sensitive, Q whereby certain [desirable results may be'acc0m-. 'plished.

' Another object ofxmy invention resides in 'a arrangement for .a facsimi1e Another object of my invention is to accomplish the above obj-ect'sin'a verysimple' and inexpensive manner;- J V Additional objects f my invention-will be disclosed in the'following description cff'my inven- "tion; taken in conjunction-with the accompany- ,ing drawing wherein the single'figure -represents a'plan view loffiapparatus embodying my invention, a s-adapted to a transmitter of a commercial Referring more particularly tothe drawing, the

'apparatusdisclosed comprises a; source 1 of light energy enclosed byfa protective 'tube3, which,in addition? to its protective function, is utilized'as a light -mask.t;A- narrow slit 5 in the'tube.3'pr0 'videsfor theproduction-or creation ofa beam of:

'jenergy externally" of said tube,said beam tobe utilized for scanning purposes. 7 2

{Associated with the 'ligh'tsource 1 and mask 3, I providea chopper mechanism; the general pur- =poseof which is'to interrupt the'beamof-energy' at a predetermined rate, preferably at a frequency The which is'modulated by variations in picture intensities, aswill be'more fully emphasized in de- 7 v r I scribing theapp'aratus'foripro'ducing'the desired or dummy map and then transmitted. The rej v-ided with a plurality of slits 9 in spaced'relationship" about its cylindrical'surface, the surface -p'ortions' between said slits being "individually of sufficient-widthto substantially ,cover the slit 5 and thus cut off the'beam of energy atidefinite intervals; for a very "small, fraction of a second. The chopper structure just described constitutes a novel improvement in choppers and constitutes the 'subjectmatter' ofli atent No; 1,877,566, granted"Sept; 13,- 1932, in which I am a jo'intapplicant. A support orholder for mounting a View 11 or facsimile to be transmittedcomprises a; cylindei- 1 3 about which said view, is adapted tobe -wrapped and? to which it i is. temporarily secured.

The cylinder, when in action is caused to rotate mitted, these variations resulting in a modulation of the audio-frequency current produced by the chopper structure. 1

7 The transformation of the modulated beam into corresponding electric currents is finadeflpossible by the use ofphoto-sensitive devices ,l5'con-l v nected in an electric circuit and so positioned as to receive a large proportionof-thereflected Various means have been resorted to; for obtaining a sufficient portion of the reflected energy.

energy to operateirthe' cellsa practical" and efficient :manner; :Cells of specialflconstruction have been used,ga'n'd; refiectorsuoi .various types have been tried for concentrating the l'l-refiected ener'gy uponfthe cathode of a-photojecell. Special- 1y constructed ztubes are: e'xpensivej,.,and artificial energy reflectors are inefiicient; I have obtained excellent results-with the :use of .two-photo-cells fo'fistandard constructiongoneoneachside oi the beam of energy and rather closeto the:picture. A su'fiicient portion ;of' the :reflected energy will strike thecellstovproduce=the'desired results. The

use of a pair of standardcells, 'as disclosed, coma prises, inasoifanasIrarn' awarea anovel-improvement in facsimile transmitting' apparatus and. reduces both the initial cost-and the upkeep of suchapparatuS-w g The apparatus- :so far :described is capable of transmittmg facsimilesa in the I normal -manner.

In order'to render such apparatus capable-of secret orselective transmission, I1removably posi- ..'tion, in the pathof the beam of energy, a filter V17 capable of "intercepting,vundesirable, components of :said beam and passing l -only certainflesirable components. 'In rmygl-preferred embodi -'-ment, the filter whichI utilizecom'pris es a small piece of red glassfor other translucent material, capable of intercepting :all the undesirable color components from thezbeam except; oflcourse', the

red component, to. which component, the normal 1 standard photo-cells are; quitelsensitive; The red component, in striking the view or picture-to be transmitted, will-be reflected with substantially equal intensityfroma picture element having a .red back ground assfromone havinga white back ground; and it is tothis phenomenon that Lmay attribute the operativeness of my inventionm lhe modulationv of the current the photo-cell-ciricuits will; be substantially the. same for thered portions of the picture: as for the white and,

I soifar as 'the'receivin'g apparatus isccmcerned, the

-color merges into that oil-another.

redrportions of the'picture being transmitted do not exist; The received picture, accordingly; will ,showwhite where athe transmittedpicture shows red. It may bewstated, therefore, that the one "Referring'back-to the practical adaptations of ,my invention, the above description-readily suggests the 'mannenin which the desired results may be obtained. Thoseelements of the picture .or-subject which it is desired shall not be transmitted should beprinted or'writtenin-red, and,

I with. a filter-win the, :pathof the ,beam which is .capable of'intercepting' all undesirable compowenjents thereof, thus permitting only the red comwhich cases, with the use of suitable photo-' sensitive devices, picture elements corresponding to the filtered beam will merge with the background of the view or picture, as received.

Also, I'consider it to be Within the scope of my invention to provide, in place of a single filtering meansfa color wheel comprising a plurality of .filteringmeans disposed about its circumference, .wherebyany desired filter'may be easily acces- 'sible.

Q In lieufof independent filtering means, as described'abov'e, it is also within the province of my invention to utilize a source of energy having inherently the desired characteristics, such as various colored flames, or I"*'mightlma1 :e use of various colored light bulbs :or other. 'si'milarJcQn;

trivancesr r V 1 v,

lWhile the above description of my'invention has related more or less to the use of lightarays 'as'a scanning medium,;I consider my methodand the broad principles of myinvention as cover [ing the use of a' beaml'of energy ingeneral, whether it be a ray of the visible spectrum or an infra-red or ultra-violet ray etc. there being no sharp physical distinction existing .between .zthemi.

a In. view of .the conditions stated above and the fact that various additional modifications of: the instrumentalities described which might be. suggested which would be within. the scopeof my inventioml do not desire to be limited to the 1 specific details set forth except insofar as may be required by the prior art and by theappended claims: 1 U 11:. q I claim as ;my invention; 1, Y 1, The methodof selectively transmitting views comprising preparing a subject having portions thereof which it is not desired to transmit; of colors-distinct from other fcolors'which it is desired to transmitysaid other colors comprising a view inthemselves',r-producing a beam of en.- ergyhavingthe characteristics of being reflected =-:wit-h substantially equal'intensity from said dis- 'tinctivecolors and-causing said beam toscan said subject and thereafter reproducing said viewinto thefform of a record in which the rundesirable colors are merged into a common color. 2. -In view-transmitting apparatus, means for 'producing'a beam of energy, means for causing said beam to scan a view to be, transmitted whereby said bearnwill "be modulated; said view :ha'ving guiding indications thereon which are distinct in ;color from the rest of theview-gand "means for transforming said modulated beam vices; situated adjacent tosaid: beam and to said viewsaid photo-sensitive devices being substantially equally sensitive; to both the background of saidview and the color of said'guiding indications whereby said guiding indications'will becomefrnerged with the background ,as reproduced. V

3. In a system of, theiacsirnile .type wherein a beam of energy-scans a view to be transmitted and whereinthe beam asmodulated bythe View 7 is directed upon photo-sensitive'means, themethod of reproducingdesiredportions onlyof a view, said'method comprising preparing a View, having of said view 1beamof energy scans'a view to be transmitted] and wherein the beam as modulated by the view A is' caused, in turn, to modulate an electric cur-, rent-the method of transmitting selected portionsp V v 1,927,900 1 portions thereof which it is not de'siredto trans-f mit, of a color' distinct'fromthe color ofother portions which it is desired to transmit, scanning a'continuous area'of said view,'-modifying the beam to affect the photo sensitive device in the same manner when directed towardthe undesired portions of the view as when the beam is directed toward" the backgroundof said view,"

and reproducing said view-into" the form of a record-in which the undesirable portions are merged with the'background. v

. 4. In a system of the facsimile type wherein a of a view, said method comprising giving to the undesired portions of the view a color characteristic differing from that of the desired portions, modifying said beam when directed toward the undesired portions of the view, to modulate an electric current. in the same manner when directed toward the undesired portions of the view, 7 as said view and reproducing said'view into the form of a record in which'the undesirable por-' tions are merged-with the background.

tions are merged with the background.

is, in turn, caused to modulate'an electric current, the method 'of transmitting comprising placing a view on paper having indicating means thereon of different color characteristics than said view for facilitating theplacing of said view, said indicating :means being undesired 'in the reproduced view, modifying theqscanning beam' to 'efiect the current in the same manner when' directed toward the undesired portions, as when said, beam isdirected toward the background of the viewand reproducinglsaid view into the form of a record ,in which the undesirable por- 6 The method of secret signalling with appa ratus of the facsimile type, comprising placing 1 information on paper with the aid of indications 'on said paper, electrically transmitting to a receiving station said information to. the exclusion of said indications and reproducing saidinformation on paper having similar indications thereon whereby said information may be interpretedi 160 VERLlE R; PHILPO'IT. I

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