US2083995A - Television - Google Patents

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Publication number
US2083995A
US2083995A US510705A US51070531A US2083995A US 2083995 A US2083995 A US 2083995A US 510705 A US510705 A US 510705A US 51070531 A US51070531 A US 51070531A US 2083995 A US2083995 A US 2083995A
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United States
Prior art keywords
grid
cathode
light
elements
anode
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Expired - Lifetime
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US510705A
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English (en)
Inventor
Henroteau Francois Char Pierre
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
ELECTRONIC TELEVISION Co
ELECTRONIC TELEVISION COMPANY Ltd
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ELECTRONIC TELEVISION Co
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Application filed by ELECTRONIC TELEVISION Co filed Critical ELECTRONIC TELEVISION Co
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J31/00—Cathode ray tubes; Electron beam tubes
    • H01J31/08—Cathode ray tubes; Electron beam tubes having a screen on or from which an image or pattern is formed, picked up, converted, or stored
    • H01J31/26—Image pick-up tubes having an input of visible light and electric output

Definitions

  • This invention relates to television, one object being to transmit either. by wire or by radio the moving images of scenes under ordinary illumination and at the same time provide that the image transmitted be exceedingly sharp and well defined, showing even the smallest details.
  • Another object of the invention is to permit the transmission of animate or still views under ordinary daylight illumination regardless, within limits, of the size of these views, that is to transmit all views which it is possible at present to photograph with a moving picture camera.
  • a further object of the invention is to provide a method whereby each point of the scene to be 15 televised can be impressed on the photoelectric surface for a greater time than has hitherto been possible.
  • a still further object of the invention is to provide a method whereby all the points of the scene to be televised are simultaneously projected on the transmitter and not successively projected thereon, as is the case with all practical methods of television now in use.
  • transmission is divided into three periods of equal length, the scene being projected on the transmitter during one of these periods. Since all the elements of the scene are simultaneously projected on the transmitter, the light from each element of the former falls on the latter for one third of one sixteenth of a second, that is for almost four thousand times longer than in known methods. If, however, the number of elements into which the scene is divided increases, then this proportion becomes still greater.
  • a very strong spot of light is caused to scan the entire surface of the transmitting screen on which the scene has been projected. The time for which this scanning beam will act upon one element of the transmitter will be ten thousand times shorter than the time for which the light of the scene acts upon the same element.
  • the light of the scanning beam can be made, on the average, ten thousand times greater than the light received from the scene. Therefore, the electric energy liberated from one element of the photoelectric material of the transmitter will be of the same order of magnitude as the energy liberated by the light of the scene which strikes that element.
  • the energy available for the transmission of the scene by my method will be, on the average, a number of thousand times greater than the energy available for the transmission of the scene by all practical methods.
  • the regeneration of the cell is performed according to my present invention in a manner entirely different from that disclosed by me in my prior patents.
  • the photosensitive coating oi the cathode is of a material which is sensitive to light in the visible spectrum but practically insensitive to ultra-violet light
  • the coating of the metallic elements of the grid is of a material which is insensitive to visible light but sensitive to ultra-violet light.
  • cathode being practically unaffected by this beam. I may, if necessary. provide means for screening the cathode from the beam while exposing the grid thereto.
  • I provide a cathode in the form of a plate having a coating of photo-sensitive material thereon.
  • An anode is also provided within the cell, and between the anode and the cathode, very close to the latter,
  • This grid is formed of a large number of quartz fibres each fibre having a number of mutually insulated metallic elements thereon, the number of the fibres and the number of elements on each fibre depending upon the degree of detail desired in the final picture.
  • Mounted on a shaft is a suitable shutter for admitting the light of. the view, the scanning beam and the ray of ultra-violet light through three different lenses, respectively.
  • Mounted on the same shaft as the shutter are suitable commutators for effecting the various electrical connections necessary for the anode and cathode.
  • cathode and anode are grounded and a strong beam of ultra-violet light is projected on the grid.
  • the metallic elements of the grid which are composed of a metal, such as zinc, sensitive to ultraviolet light, will emit electrons until all the elements reach a uniform potential which will be very nearly zero. The emitted electronswill be captured by the cathode or by the anode.
  • Figure 1 is a general view of my apparatus partly in section.
  • Figure 2 is a plan view of the grid.
  • Figure 3 is a plan view of the shutter showing the relation of the various lenses thereto, and
  • Figure 4 is a view showing a modification of the apparatus used for regenerating the grid.
  • l is a photoelectric cell which is formed with a flattened part 2 having a quartz window 3 therein and two lenses 4 and 5 mounted adjacent thereto, the centres of the two lenses and that of the quartz window being at the aploes of an equilateral triangle, as shown in Fig. 3.
  • the part 2 is opaque except for the quartz window 3 and the parts directly behind the lenses 4 and 5.
  • Mounted within the tube is an anode 6 and a screen 1 constituting a cathode and being formed of an electro-conductive plate 1a having thereon a layer 8 of material such as caesium sensitive to visible light but practically insensitive to ultraviolet light.
  • This layer is preferably monomolecular, since it is well known that this enhances the photoelectric activity.
  • the anode 6 is made in the form of a small sphere partly to prevent its interfering with the various beams of light through the lenses 3, 4, and 5 and partly to reduce its electrical capacity.
  • This grid consists of a large number of quartz fibres ll stretched between posts ii and having thereon a multiplicity of mutually insulated electro-con-
  • the elements of the grid are formed by silver plating an extremely thin quartz fibre, then electroplating the platedfibre with a metal, such as zinc, which, while insensitive to visible light is sensitive to ultra-violet light, and finally removing the entire metal plating from the quartz at regular intervals.
  • the metallic elements-of the adjacent wires are preferably staggered with respect to one another, that is, the elements of one wire will occupy the 1, 3, 5 positions while the elements of the next wire will occupy the 2, 4, 6 positions.
  • the shutter I3 is mounted on a shaft I5 and rotates therewith.
  • Mounted on the same shaft and rotating therewith is a commutator I6 of insulating material having a metallic sector II thereon, this sector being connected to the anode 6 by means of a wire I8.
  • are arranged around thecommutator at the apices of an equilateral triangle and the angle subtended by the arc of the metallic sector I! is slightly less than 120 30 so that this sector connects-with only one contact at a time.
  • a commutator 30 similar to the commutator I6 and having a metallic sector 3I similar to the metallic sector I1 is also mounted on the shaft I5, the sector 3
  • Arranged around the commutator are three contacts 33, 34 and 35, the first being connected to ground 36, the second through negative battery 31 to ground 38 and the third to ground 39.
  • a cathode ray oscillograph '40 for scanning purposes is arranged in such a way that the light produced by the impact of its electronic stream on the fluorescent screen M will pass through the lens 5 and that its fluorescent screen M will be a conjugate plate to the cathode I with respect to this lens.
  • the cathode ray oscillograph is arranged above the apparatus and its light is reflected by the mirror 42. If desired some other form of scanning means 50 might be used, the cathode ray oscillographhaving been shownmerely by Way of example and because it is thought to be the most suitable.
  • the device for producing the ultraviolet light is shown by way of example as comprising an arc light 43 having in front thereof a piece of Jena glass 44 which will allow only the ultra-violet part of the light from the arc to pass.
  • the material with which the cathode is coated is practically insensitive to ultra-violet, it may be advisable to arrange the apparatus in such a manner that the ultra-violet light for regenerating the grid will be prevented from striking the cathode coating.
  • This arrangement is illustrated in Fig. 4, in which only those parts directly relevant to it are shown.
  • the reproduction of the grid on the plate may.,be performed in any suitable manner, either photographically or otherwise.
  • the finished plate is placed in such a position that it will form a conjugate plane to the grid 9 with respect to a quartz lens 48 which is used in this case instead of the quartz window 3.
  • the source of ultra-violet light is positioned so that The whole apparatus will be suitably magneti- 4 cally and electrically shielded.
  • the scanning beam of the cathode ray oscillograph is extremely strong and of constant intensity so that under its influence the same number of electrons will be detached from each successive point of the cathode which it strikes and attracted to the anode by reason of the comparatively high positive potential of the latter.
  • One of the metallic elements I2 of the grid 9 will,
  • the anode will receive an electronic currentmodulated in accordance with the intensityof the light of the different parts of the view which was originally projected on the cathode.
  • the modulated electronic current received by the anode will modulateits potential and these potential modulations will be impressed on the grid 28 of the first thermionic valve 28 of the transmitter. From here transmission is by known methods.
  • the anode being in the form of a small sphere, has a very low electric capacity and.
  • the zinc coating of the metallic elements II of the grid 9 will emit electrons, which will be attracted by the cathode and also by the anode, since both these electrodes are grounded and therefore positive with respect to the various elements of the grid which are at various negative potentials.
  • an element of the grid has emitted enough electrons to acquire a slight positive potential then any further electrons which it emits will be reattracted to it and it will retain the same potential. In this manner all the elements of the grid will be brought to a uniform potential which will be slightly positive.
  • the operation is only slightly modified.
  • the opening I of the shutter l8 registers with the quartz lens 48
  • the ultra-violet light which has passed through the screen 45 and'has been reflected by the mirror 49, passes through the lens 48 and strikes the wires of the grid 9. Owing to the construction of the screen 'the light is prevented from striking the cathode.
  • the elements of the grid are brought to a uniform potential as described above.
  • the irequency'band necessary for transmission might be narrowed if, instead of using only one apparatus where the whole cycle of operations is completed in one sixteenth of a second, three on the receiver.
  • Very strong, enlarged and contrasted images of very faint, still objects could be produced with my system owing to electrical amplification.
  • the shutter I3 would be brought to a position to allow the view to fall on screen 8 for a suitable length of time.
  • the shutter would then be rotated to a position to allow scanning of the screen and this scanning could be repeated without any intermediate operation for as long as desired since the electrostatic image of the object would always remain on the grid.
  • My device could for instance be attached .to a powerful astronomical telescope and, while the image focussed would be large and weak, a very vivid strong image would appear
  • the device could also be attached to a microscope andpermit hitherto invisible objects to be seen.
  • the effect produced by the scanning beam'of the cathode ray oscillograph may be achieved in a modification of my invention by another arrangement.
  • the cathode is formed of a an extremely thin plate of aluminium or berylium, the latter being preferred owing to its low density.
  • This plate is coated on one side with a monomolecular layer of photo-sensitive material such as caesium, this side of the plate facing toward the grid.
  • the plate itself forms the screen of a cathode ray oscillograph, the electronic stream of the latter being directed against the uncoated side of the plate, namely that facing away from the grid.
  • the cathode ray oscillograph comes into operation to cause an electronic stream to scan the uncoated side of the plate.
  • the electrons in this stream are moving at an extremely high speed and will pass through the plate. In so doing, however, their speed will be considerably reduced so that after their passage they will be moving with approximately the same speed as the electrons emitted from the photo-sensitive surface 8 as described in connection with Figure 1.
  • the berylium plate being of uniform thinness and density, the speed of the electronic stream, after its passage therethrough, will be uniform for all points. After they have passed through the plate the electrons will be attracted by-the anode, the number reaching the latter from any point of the cathode being controlled in each instance by the potential of the metallic element of the grid near which they must pass.
  • a method or electrical image transmission 15 which comprises impressing an image upon a photosensitive surface, collecting the electronic emission from said surface to form an electrostatic reproduction of said image on means other than said surface, causing an electronic stream 20 to be emitted from every point of said surface in sequence, causing said stream to be modulated by said electrostatic reproduction, picking up the modulated stream at an anode, and finally causing said electrostatic reproduction to disappear.
  • a method of electrical image transmission which comprises impressing an image upon a uniformly electro-conductive and uniformly photosensitive surface, collecting the electronic emission from said surface to form an, electro- 30 static reproduction of said image on means distinct from said surface, causing an electronic stream to be emitted from every point of said surface in sequence, causing said stream to be modulated by said electrostatic reproduction and 35 causing the modulated stream to be attracted by an anode.
  • a method of electrical image transmission which comprises impressing an image upon a surface photosensitive only to visible light, collecting the electronic emission from the said surface to form an electrostatic reproduction of said image on means distinct from said surface and photosensitive only to ultraviolet light, causing an electronic stream to be emitted from every point of said surface in sequence, causing said stream to be modulated by said electrostatic reproduction, picking up the modulated stream at an anode, and finally causing said electrostatic reproduction to disappear by means of ultraviolet light.
  • Apparatus for the electrical transmission of images comprising a cell, a photosensitive surface within said cell, means for impressing an image on said surface, separate means in the form of a grid also within said cell, formed with a multiplicity of mutually insulated electroconductive elements, for retaining an electrostatic reproduction of said image, means for thereafter causing said photosensitive surface to emit an electronic stream from every point thereof in sequence, and an anode for receiving said electronic stream modulated by said electrostatic reproduction.
  • Apparatus for the electrical. transmission of images comprising a cell, a photosensitive surface within said cell, means for impressing an image on said surface, separate means in the form of a grid also within said cell, composed of a number of'insulating fibres each having a number of mutually insulated electroconductive elements thereon, for retaining an electrostatic reproduction of said image, scanning means for causing said photosensitive surface to emit an electronic stream from every point thereof in sequence, and an anode for receiving'said electronic stream modulated by said electrostatic reproduction.
  • Apparatus for the electrical transmission of images comprising a cell, a surface within said cell, photosensitive only to visible light, means for impressing an image on said surface, a grid also within said cell formed witha multiplicity of mutually insulated electro-conductive elements, said elements being photo-sensitive only to ultra-violent light, said grid serving to retain an electrostatic reproduction of said image, means for causing said photosensitive surface to emit an electronic stream from every point thereof in sequence, and means for thereafter projecting ultraviolet light on said grid to neutralize said electrostatic image.
  • Apparatus for the electrical transmission of images comprising a cell, a photosensitive surface within said cell, a grid also within said cell composed of a multiplicity of mutually insulated electroconductive elements, said elements being sensitive only to light of a different wave length from that to which said surface is sensitive, means for impressing an image on said surface, means for causing the elements of said grid to collect the resulting electronic emission from the adjacent portions of said surface and thus assume various negative potentials, means for scanning said surface with a beam of light, and means for causing another electrode in said cell to attract the resulting electronic stream, the electroconductive elements of said grid serving to modulate the last mentioned electronic stream.
  • Apparatus for the electrical transmission of images comprising a cell, a surface within said cell, photosensitive only to visible light, means for impressing an image on said surface, a grid also .within said cell formed with a multiplicity of mutually insulated electroconductive elements, said elements being photo-sensitive only to ultraviolet light, said grid serving to retain an electrostatic reproduction of said image, means for cause ing said photosensitive surface to emit an electronic stream from every point thereof in sequence, means for thereafter projecting ultraviolet light on said grid to neutralize said electrostatic image, and means for shielding said photosensitive surface from said ultraviolet light.
  • Apparatus for the electrical transmission of images comprising a cell, a photosensitive surface within said cell, means for causing an electronic stream to be emitted from every point of said surface in sequence, means for impressing an image on said surface, separate means in said cell for retaining an electrostatic reproduction of said image and for modulating the emitted electronic stream in accordance with the electrostatic reproduction, and an anode for receiving the modulated stream.
  • Apparatus for the electrical transmission of images comprising acell, a photosensitive surface within said cell, means for causing an electronic stream to be emitted from every point of said surface in sequence, means for impressing an image on said surface, separate means in said cell for retaining an electrostatic reproduction of said image and for modulating the emitted electronic stream in accordance with the electrostatic reproduction, an anode for receiving the modulated stream, and means for causing the electrostatic reproduction to disappear.
  • a method of electrical image transmission the steps which comprise impressing an image upon a photosensitive surface, collecting the electronic emission from said surface on means comprising a multiplicity oi! mutually insulated e1ectroconductive elements, to form an electrostatic reproduction 01' said image thereon, scanning a surface to cause an electronic current of substantialiy constant intensity to be emitted from areas of said surface successively scanned, modulating said electronic current by said electrostatic reproduction, picking up the modulated current at an anode, and controlling the operation '01 a 10 transmitting device in accordance with the successive changes in value of said modulated current.
  • means for scanning a screen to cause an electronic stream to be emitted therefrom means separate and distinct from said screen tor modulating the electronic stream in accordance .with the intensity of thedight 0! an image, and

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  • Image-Pickup Tubes, Image-Amplification Tubes, And Storage Tubes (AREA)
  • Investigating, Analyzing Materials By Fluorescence Or Luminescence (AREA)
  • Image Input (AREA)
  • Printers Or Recording Devices Using Electromagnetic And Radiation Means (AREA)
US510705A 1931-01-20 1931-01-23 Television Expired - Lifetime US2083995A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CA2083995X 1931-01-20

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US2083995A true US2083995A (en) 1937-06-15

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US510705A Expired - Lifetime US2083995A (en) 1931-01-20 1931-01-23 Television

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US (1) US2083995A (en, 2012)
BE (1) BE401803A (en, 2012)
FR (1) FR769500A (en, 2012)
GB (1) GB413996A (en, 2012)
NL (1) NL43519C (en, 2012)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2442287A (en) * 1943-08-13 1948-05-25 Pye Ltd Means for reproducing X-ray images
US2651674A (en) * 1949-02-18 1953-09-08 Cathodeon Ltd Television transmission from intermittent film by means of pulsed pickup tube
US2655554A (en) * 1948-06-03 1953-10-13 Emi Ltd Generation of picture signals for television transmission
US2756364A (en) * 1951-01-05 1956-07-24 Pye Ltd Television transmitting apparatus
US2919364A (en) * 1955-10-04 1959-12-29 Ibm Photocell with transparent photocathode
US3112422A (en) * 1958-10-06 1963-11-26 Gebhard K Schneider Photo-electric cell for the automatic exploring of curves

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2442287A (en) * 1943-08-13 1948-05-25 Pye Ltd Means for reproducing X-ray images
US2655554A (en) * 1948-06-03 1953-10-13 Emi Ltd Generation of picture signals for television transmission
US2651674A (en) * 1949-02-18 1953-09-08 Cathodeon Ltd Television transmission from intermittent film by means of pulsed pickup tube
US2756364A (en) * 1951-01-05 1956-07-24 Pye Ltd Television transmitting apparatus
US2919364A (en) * 1955-10-04 1959-12-29 Ibm Photocell with transparent photocathode
US3112422A (en) * 1958-10-06 1963-11-26 Gebhard K Schneider Photo-electric cell for the automatic exploring of curves

Also Published As

Publication number Publication date
BE401803A (en, 2012) 1934-04-30
FR769500A (fr) 1934-08-24
GB413996A (en) 1934-07-26
NL43519C (en, 2012) 1938-07-15

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