US1747988A - Transmission of pictures and views - Google Patents

Description

Feb. 18, 1930. c, A, SABBAH 1,747,988

TRANSMISSION OF PICTURES AND VIEWS Filed May 27, 1925 7'0 WIRE 0/? HAD/0 TRANS/WT 7'//V6 AFPARA T06 Fig. 2. 6 l4 0 III 0 Ill 0 m Ill Inventor: Camille ASabbah,

b5 His Attor immed Feb. is, race E a. sen,

or summar new YORK, ASSIGNQB ro onnnnanmnormo COMPANY, A conroaerron or NEW YORK TRANSMISSION OF AND VIEWS Application filed may 27, 1925. Serial No. 38,271.

My invention relates to the electrical transmission of pictures and views. An object of my invention is the provision of improved method and means forthe rapid transmission of still pictures and views and for the transmission of moving pictures. and views.

A further object of my invention is to provide apparatus for this have no moving materia parts and which is thereby free from inertia efi'ects. In accordance with my invention I project a an imageof the picture or view to be transmitted on a plate of photo-resistance material, that is, a material whose resistance varies it in accordance with the intensity of light falling upon it. On one face of this plate are a lar e number of small conductors forming a gr' A .cathode ra which is directed toward the opposite aceozt this plate and .20 which is caused rapidly'tc scan the plate is connected in circuit with the gridand a suitable amplifying means. lhe return current of electrons is thereby proportional at any instant to the resistance of the small area of i the resistance plate engaged by the cathode cathode ray is caused to take, and Fightd shows a modified form of wave.

- In Fig. 1 I have shown diagraatically a cathode tube 1 having at one end the filament 2 which. is adapted to be heated bythe battery 3. In front o fthc filament 2 is the anode 4 connected with the filament through. M the battery 5 and having a small opening therein through which the. cathode ray is di- 4 rected toward the plate 6 arranged in the tube at the opposite end thereof. .A suitable lens 8 is shown connected by 'abellows 9 with the so tube so that it may be adjusted to produce a purpose which shall i'two pairs of plates relative to each other the ray can be made to follow any desired path.

sharp image on the plate 6 of the picture or view represented by the arrow 10.

The plate 6, a fragment of which is shown in elevation and section respectively on a greatly enlarged scale in Figs. 2 and 3, comprises a glass plate 12 having on its rear side a thin layer or film 13 of a substance whose resistance changes greatly with the degree conductin paths are provided between the film and t e opposite side of the glass plate which is the side facing the cathode 2. The metallic lines 14 are joined together and are connected by battery 16, resistance 11 and conductor with battery 5 and cathode 2.

Within the tube 1 and arranged on opposite sides of the path of the cathode ray at a point preferably adjacent the anode are two pairs of spaced parallel plates 18 and 19, the one pair being placed at right gles to the other. As is well understood by those skilled in the art, if charges are given ,to these pairs of plates the cathode ray which passes between the plates will be distorted or bent and that by suitably varying the charges on the If the picture or view to be transmitted is still, movement of the ray in scanning the image need only; have such speed that the movement of the corresponding spot of light in the receiver may not be detected by the eye of the observer. For the transmission of a moving picture or view the ray should scan the entire image at least sixteen to twe ty times per second to revent the efifect of fllckering of the transmitted picture.

Various methods may be employed for r other suitable metal I therein to show the various all varying the held between the plates 18 and the plates 19 to cause the ray to cover the image on the plate '6 with the desired speed. @ne arrangement whereby the plates 18 and 19 may be energized in a manner to cause the ray to travel in spirals such as shown in Fig. 5 at the desired rate is shown diagrammatically in Fig. 1. A well known form'of selfrectitying circuit is employed comprising the two pliotrons 20 and 21. When the rectifying circuit is fed by the transformer 22 connected for example to a ten cycle source of alternating current, the current in the oscillation circuit 23, 24, 25, 26 may be of the form represented by 27 in Fig. 4, the high fre= quency oscillations being modulated by the ten cycle current. A winding 28 in inductive relation to the oscillation circuit is connected in circuit with an inductance 29 and resist ance 30. One pair of plates, for example plates 18, is connected across the inductance 29, the other pair of plates is connected across the resistance 30. By this arrangement the currents traversing the two pairs of plates are substantially in quadrature with each other and each has the form illustrated by Fig. i. The resulting efiect upon the cathode ray is to cause it to trace upon the plate 6 spiral aths such as illustrated for example by 31 in haig. 5. Eve small unit area of the image on the late is thus covered many times per second y the ray. At this point of the description it is desired to point out that the drawing is purely diagrammatic in character and that no attempt has been made true or relative proportions. ikewise in the diagrams forming'Figs. i and 5, as well as Fig. 6 to to be described hereinafter, the hi h frequency wave and the resultin pitch of the s iral 31 are not illustrative 0 actual conltions butrather have been shown having such values as is found most convenient in illustrating the idea. 7

The current impulses traversing the resistance llasia result of the cathode ray scanning the'image on plate 6 may be transmitted to a distant station either by wire or by radio. Two amplifying pliotrons 32 and 33 are shown connected together by the transformer 34, the grid and filament of the first pliotron being connected with the resistance 11 and the late of the second pliotronbeing connected through the transformer 35 with a suitable wire or radio transmittmgapparatus not shown. 7 V

In using the a paratus, the ten cycle current supplied to t e transformer 22 causes the cathode ray which is projected from the oathode 2 through the opening in the anode 4 to be deflected and to trace spirals on the plate.

6, a complete spiral being traced durin each of the intervals a-b, bc, 0-41! and of Fig.4. At the same time, the image of the picture or view to be transmitted is being arts in theirmenses projected by the lens 8 upon the plate 6. As the cathode ray, which in diameter should not be less than the distance between adjacent plugs 15 in order that the circuit shall not be interrupted, travels over the late 6 in a spiral path as shown in Fig. 5 or example, the resistance ofiered to the electron stream by the film 13 varies in accordance with the brightness of each small unit area of the image upon which the ray falls. The resistance of the film 13 is relatively large but only that small portion of the film between the plug or plugs 15 upon which is falling the ray at any instant and the adjacent metallic lines 14 is included in the circuit. Thus the current through the resistance 11 is at any instant a measure of the illumination of the particular spot of the image upon which the cathode ray is falling at that instant and the resulting potential drop across the resistance after being amplified is transmitted by wire or radio'means, not shown, to the receiving station.

Theray may be made narrow enough and the turns of the spiral close enough to produce a picture having the desired sharpness. The entire image is thus covered twice dur- 3 ing each half wave of the ten cycle current.

lumination and brightness in speaking of,

the image formed upon the plate '6, I desire it to be understood that I use these terms in their broadest sense to cover not only the visible ortions of the spectrum but also the invisi le'portions thereof since the material of the photo sensitive late can be selected so that it will respon to visible or invisible re s.

nstead of causing the cathode ray to cover the image by tracing spirals upon the plate 6 it may be caused rapidly to sweep upand down over the plate while advancing back and forth across it, thus tracing a ath after the fashion of that illustrated y the line 37 in Fig. 6. In this way the entire image is covered during each horizontal traverse of the ray. For moving the ray in this manner the self-recti ing circuit illustrated may be dispensed wit and one pair of the deflecting plates may be connected to a source of sustained high frequency while the other air of plates may be connected to a source oi: lower frequency which may be of the order of sixteen or twenty cycles per second or higher if desired.

By whichever method the ray is moved, it will be noted that the apparatus includes no material moving parts and hence no inertia efiects have to be considered. The only moving element is the cathode ray and this is af.dapted to-respond instantly to the deflecting orce.

For receiving the picture or view thus transmitted I may use a cathode ray tube having means similar .to that already described for moving the ray and in which the 5. In apparatus for the transmission of voltage between anode and cathode is caused pictures and views, a plate having on one to vary in accordance with the impulses reace thereof thallium sulphate, a conductive ceived from the transmitting station. The grid on the thallium sulphate and a plural- 5 ray in this case ma fall on a semi-transit of conductors extending throu h the 70 parent film of hosp orescent substance and p ate and arran ed intermediate t e elethe plate may e viewed through a suitable ments of the gri lens or eye piece. Synchronization of the In witness whereof, I have hereunto set transmitting and receiving apparatus is obmy hand this 26th day of May, 1925.

m tained by employing oscillation circuits 23, OAMILLE A. SABBAH. 75

24,25 and 26 in the transmitter and the receiver having the same fre uency and by slight manual variations in t e constants ofthe circuit maintaining the exact synchronization necessary to prevent distortion of the V is a V picture.

In my Patent, No. 1,694,982, granted Dec. 11, 1928, I have disclosed a different embodimerit of my invention utilizing a cathode ray for scanning purposes and have claimed in a as that application the broad features common to that case and the present application.

What'I claim as new and desire to secure by Letters Patent ofthe United States, is:

1. Apparatus for the transmission of pic- I 9o tures and views comprising a cathode ray tube, a resistance element whose resistance varies with its illumination, means for projecting an image on the element, means for causing the cathode ray to scan the image, 95

and circuit connections adapted to provide a return path from a plurality of small areas of said element to the'cathode of said tube.

2. Apparatus for the transmission of pictures and views comprising a cathode ray 10c tube, a light-sensitive resistance element therein having a plurality of conductors on one face thereof, means for rojecting an image on said face, means or directm the p cathode ray toward said element an for moving the same over the element, and circuit connections between the source of said my and said conductors.

3. Apparatus for the transmission of pic- 5 tures and views comprising a cathode my 110 tube, a plate therein having on one face a film whose resistance varies in accordance with the illumination thereof, means for projectv ing on the film an image of the picture or view to be transmitted, a plurality of spaced 11o conductors on the film, a plurality of spaced conductors extending through the plate to the op site face thereof, means for causing the cat ode ray to sweep over said opposite face and circuit connections between the mo rfzfi'tllliode and the spaced conductors on the 4. In apparatus for the transmission of pictures and views, a plate having on one so face thereof light sensitive resistance ma'ted 125,

- rial, a conductive grid on the resistance material, a plurality of conductors extending through the plate and arranged intermediate the elements of the grid and source of C5 electrons interconnected with said grid. I l

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