US2201069A - Method of and means for television transmission - Google Patents

Method of and means for television transmission Download PDF

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Publication number
US2201069A
US2201069A US114161A US11416136A US2201069A US 2201069 A US2201069 A US 2201069A US 114161 A US114161 A US 114161A US 11416136 A US11416136 A US 11416136A US 2201069 A US2201069 A US 2201069A
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US
United States
Prior art keywords
image
scanning
diaphragm
mosaic screen
cathode ray
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Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
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US114161A
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English (en)
Inventor
Wolff Hanns-Heinz
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.)
LOEWE RADIO Inc
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LOEWE RADIO Inc
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Filing date
Publication date
Application filed by LOEWE RADIO Inc filed Critical LOEWE RADIO Inc
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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
    • H01J31/28—Image pick-up tubes having an input of visible light and electric output with electron ray scanning the image screen
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N23/00—Cameras or camera modules comprising electronic image sensors; Control thereof
    • H04N23/40—Circuit details for pick-up tubes

Definitions

  • the invention relates to a method of and means for television transmission, making use of cathode ray tubes, in which a storage of light-electric excitations and the initiation of current impulses corresponding to the stored excitations by cathode ray scanning or the like take place. Arrangements of this nature have been developed according to the point of view of raising, by way of storage, the image-content impulses employed for transmission purposes to sufliciently
  • the invention is based on the idea that if too great a length of time elapses between illuminating and scanning, the electric image on the light-electric plate varies owing to mutual influence of the different charged image elements, especially in the sense of softening of contrast.
  • a compensation of the charge is caused in part by capacitative effect of the different image elements one upon another, and in part by the reactionary effects of space charges, which form in front of the image elements, are
  • FIG. 1 shows diagrammatically the parts of the total arrangement essential for a form of embodiment of the invention, whilst in v 4 Figs. 2 and 50-0 is shown the image areaor image field for illustrating certain considerations important for the invention, in
  • Fig. 3 a diaphragm arrangement not in accordance with the invention. and in each of Figs. 4 and 6 a diaphragm arrangement accord- 5 ing to the invention.
  • the intermittent uncovering and interruption of the passage of the ray from the object to be transmitted, or a part thereof, to the light-electrically sensitive plate, or a corresponding part thereof, may be performed by, means ofa rotating diaphragm.
  • the opening or openings in this diaphragm which uncover or partially uncover the passage of the ray must appear sharply on the light-electrically sensitive plate simul- 15 taniously with the object of reproduction.
  • the diaphragm should accordingly be arranged if possible either immediately in front of the lightelectrically sensitive plate or immediately in front of the object of reproduction.
  • the former ar- 20 rangement is only. possible if the light-sensitive plate is situated sufficiently near the wall of the cathode ray tube.
  • I is the object 5 to be reproduced
  • 2 the cathode ray tube with the light-sensitive plate 3, 4 the diaphragm having the axis of rotation 5,
  • B a reproducing lens, which projects an image l of the object I on to the diaphragm 4, and 8 a second reproducing lens which reproduces the image I, so far as it is uncovered by the diaphragm, on the plate 3 at l.
  • the difference in time between shading and scanning accordingly amounts, for the image point an, to At.
  • the point am is shaded at the same moment as the point an, but is scanned by the cathode ray by the amount later than the point am, assuming that is represents the image-scanning period in seconds.
  • FIG. 3 accordingly shows disadvantages which are to be obviated by the method according to the invention, as in this arrangement there is no usein-providingAt with a value which is small in relation to the image scanning period tb.
  • An arrangement according to the invention is shown in Fig. 4.
  • the arrangement is such that a shading edge ill of a diaphragmaperture moves over the image Tin such fashion that it runs parallel to the lines along which the cathode ray scanning takes place thatthe movement of said edge occurs perpendicularly to the direction of the lines in the sense ofthe sequence in which the lines are scanned by ray.
  • the greatest difference between the time intervals between the shading and the cathode ray scanning of the individual image elements is evidently approximately equal to one line period, which inmany cases may already represent a sufficient degree of conformity.
  • the arrangement should be such that the edge it! of the diaphragm aperture passes over the image I within the same period which is required by the cathode ray for scanning the image T. If the cathode ray has scanned the entire image, the line can am must in the meantime have been illuminated anew and already again shaded before the oathode ray starts the next scan. It follows that'the diaphragm t'requires to be furnished with a rim of-evenly. distributed apertures H. The dimensions and the distribution of these apertures are determined by the following points of view:
  • the last aspect referred to is also decisive in the direct transmission of moving occurrences, in which the loss of 'timeby advance of a film is not involved.
  • the ratio between the mutual distance of two neighbouring slots and the width of a slot amounts to hi ii
  • the same, according'to-a' further feature-of the invention must-have a circumferential velocity which is equal to times-the number of image changes per second, i. e., for example in the case of 25 image changes per second and 25 slots revolution I second
  • the arrangement according to the invention has a further important advantage, which will be explained with reference to Figs. 5111-0. Be a bright red assumed to move over the image field I ('l) on a dark ground, e. g.,
  • the diaphragm 4 is constructed as a spiral aperture disc on the lines of the Nipkow disc (see Fig. 6).
  • the apertures are made in the form of longer or shorter slots or in the extreme case as openings each uncovering only one image element at a time, dependent on the extent to which it is desired to make use of the storage efiect or on whether it is desired to dispense with the same for the sake of a more complete elimination of the disturbances which the invention is intended to reduce.
  • the width of the slots is adapted to the width of the scanning lines and their number is selected to be equal to the number of lines.
  • the circumferential velocity of the disc per second is in this case equal to the complete number of image scannings per second.
  • the diaphragm 4 is then given a form which corresponds to that of the scanning discs of television transmitters operating according to the interlaced scanning method (compare for example the applications Ser. No. 36008/35 filed Aug. 13, 1935), attention being merely called to the fact that the openings may again have the form of slots extended in the direction of the lines for the purpose of obtaining a certain storage effect.
  • the arrangement according to the invention combines the following important advantages:
  • a television transmitter comprising a cathode ray tube having a photo-electric mosaic upon which the image to be transmitted is projected and which is scanned by a cathode ray, means to illuminate each element of said mosaic only for a small part of an image change period and to scan it immediately thereafter, said means consisting of an obturating diaphragm rotating synchronously with the scanning, said diaphragm having a plurality of elongated apertures being so arranged as to uncover at once at least one of the image lines.
  • a television transmitter comprising a cathode ray tube having a photo-electric mosaic upon which the image to be transmitted is projected and which is scanned by a cathode ray, means to illuminate each element of said mosaic only for a small part of an image change period and to scan it immediately thereafter, said means consisting of an obturating diaphragm rotating synchronously with the scanning, said diaphragm having a spiral of apertures similar to a Nipkow disc.
  • a television transmitter comprising a cathode ray tube having a photo-electric mosaic upon which the image to be transmitted is projected and which is scanned by a cathode ray, means to illuminate each element of said mosaic only for a small part of an image change period and to scan it immediately thereafter, said means consisting of an obturatlng diaphragm rotating synchronously with the scanning, saiddiaphragm having a spiral of apertures similar to a Nipkow disc for interlaced scanning.
  • a television transmitting device comprising a two-dimensional photo-electric mosaic screen in combination means for performing a lighting operation to illuminate said mosaic screen from the object to be transmitted, interrupting means for periodically interrupting the lighting of each element of said mosaic screen, the lighting period allowed by said interrupting means being smaller than an image change period, scanning means for performing a scanning operation to scan said mosaic screen by a ray, and means for establishing a co-operative relation between said interrupting and said scanning means such as to cause said lighting and said scanning operation to act substantially simultaneously on, though at each moment on different parts of, said mosaic screen and such as to admit the passing of at most a small time interval between the end of said lighting operation and the beginning of said scanning operation for each element of said mosaic screen.
  • a television transmitting device comprising a two-dimensional photo-electric mosaic screen in combination means for performing a lighting operation to illuminate said mosaic screen from the object to be transmitted, interrupting means comprising a rotating apertured diaphragm disposed between the place of said object to be transmitted and said mosaic screen for periodically interrupting the lighting of each element of said mosaic screen, the lighting period allowed by said interrupting means being smaller than an image change period, scanning means for performing a scanning operation to scan said mosaic screen by a ray, and means for establishing a co-operative relation between said interrupting and said scanning means such as to cause said lighting and said scanning operation to act substantially simultaneously on, though at each moment on different parts of, said mosaic screen and such as to admit the passing of at most a small time interval between the end of said lighting operation and the beginning of said scanning operation for each element of said mosaic screen.
  • a television transmitting device comprising a two-dimensional photo-electric mosaic screen in combination means for performing a lighting operation to illuminate said mosaic screen from the object to be transmitted, interrupting mean comprising a rotated apertured diaphragm' disposed between the place of said object to be transmitted and said mosaic screen ior periodically interrupting the lighting of each element of said mosaic screen, the lighting period allowed by said interrupting means being smaller than, an image change period, scanning means for performing a scanning operation to scan said mosaic screen by a. ray, optical means for producing in the plane oi said diaphragm a real image of said object to be transmitted,
  • a television transmitting device comprising apparatus for intermittently advancing a cinematographic film and a two-dimensional photo-electric mosaic screen in combination means for performing a lighting operation to illuminate said mosaic screen from said film, interrupting means comprising a rotating apertured diaphragm disposed between the place of the film-picture to be transmitted and said mosaic screen for periodically interrupting the lighting ofeach element of said mosaic screen, the lighting period allowed by said interrupting means being smaller than an image change period, scanning means for performing a scanning operation to scan said mosaic screen by a ray, means for blocking said ray during a time interval which is the sum of the time required for one advancing movement of the film and of said lighting period, and means for establishing a cooperative relation between said interrupting and said scanning means such as to cause said lighting and said scanning operation to act substantially simultaneously on, though at each moment on different parts of, said mosaic screen and such as to admit the passing of at most a small time interval between the end of said lighting operation and the beginning of said scanning operation for each element of said mosaic screen.

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  • Engineering & Computer Science (AREA)
  • Multimedia (AREA)
  • Signal Processing (AREA)
  • Transforming Light Signals Into Electric Signals (AREA)
  • Facsimile Scanning Arrangements (AREA)
US114161A 1935-12-10 1936-12-04 Method of and means for television transmission Expired - Lifetime US2201069A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE479551X 1935-12-10

Publications (1)

Publication Number Publication Date
US2201069A true US2201069A (en) 1940-05-14

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US114161A Expired - Lifetime US2201069A (en) 1935-12-10 1936-12-04 Method of and means for television transmission

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US (1) US2201069A (enrdf_load_stackoverflow)
BE (1) BE418847A (enrdf_load_stackoverflow)
FR (1) FR814775A (enrdf_load_stackoverflow)
GB (1) GB479551A (enrdf_load_stackoverflow)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2510070A (en) * 1945-05-18 1950-06-06 Farnsworth Res Corp Television scanning system
US2612554A (en) * 1949-02-18 1952-09-30 Gen Precision Lab Inc Film projector for television
US4367486A (en) * 1980-03-18 1983-01-04 Jesse B. Eichenlaub Three dimensional imaging system

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2510070A (en) * 1945-05-18 1950-06-06 Farnsworth Res Corp Television scanning system
US2612554A (en) * 1949-02-18 1952-09-30 Gen Precision Lab Inc Film projector for television
US4367486A (en) * 1980-03-18 1983-01-04 Jesse B. Eichenlaub Three dimensional imaging system

Also Published As

Publication number Publication date
BE418847A (enrdf_load_stackoverflow)
FR814775A (fr) 1937-06-29
GB479551A (en) 1938-02-08

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