US2056761A - Television and like apparatus - Google Patents

Television and like apparatus Download PDF

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Publication number
US2056761A
US2056761A US574114A US57411431A US2056761A US 2056761 A US2056761 A US 2056761A US 574114 A US574114 A US 574114A US 57411431 A US57411431 A US 57411431A US 2056761 A US2056761 A US 2056761A
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US
United States
Prior art keywords
light
scanning
image
disc
apertures
Prior art date
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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US574114A
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English (en)
Inventor
Baird John Logie
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Individual
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Individual
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Publication of US2056761A publication Critical patent/US2056761A/en
Anticipated expiration legal-status Critical
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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N7/00—Television systems
    • H04N7/14—Systems for two-way working
    • H04N7/141—Systems for two-way working between two video terminals, e.g. videophone

Definitions

  • This invention relates to two-way television apparatus, that is to say, apparatus by means of which two persons situated at a distance may see each other at the same time.
  • the invention relates more particularly to apparatus for enabling two people who are telephoning to each other to see each other simultaneously.
  • the actual or virtual position of the receiving screen at each end of a two-way television system lies within the solid angle formed by the scanning 40 beams of the co-terminal transmitter.
  • the operator at each end of a two-way television ⁇ system is scanned from the same direction as that in which he sees an image of his co-operator.
  • the present invention also contemplates the contemporaneous scanning of the operator and reconstitution of an image for his beneiit at each station, the processes of scanning and reconstitution being substantially coinitial and concurrent as regards commencement and completion of traversal.
  • I may use a transmitting disc with two spirals of holes; through one spiral the light passes; behind the other spiral are little mirrors at right angles tothe plane of the disc and directed towards the centre or the periphery of the disc.
  • Near the centre or the periphery of the disc is a plate neon tube modulated in accordance with the currents from the transmitting station. The light from this neon tube is directed by the little mirrors through the holes in the disc Vcorresponding to the receiver.
  • I use two discs, the receiving disc kbeing nearer to the observer than the transmitting disc and having perforations in it to permit the beams from the transmitting disc to pass through it without interruption, as both discs revolve, this disc ⁇ having affixed to it mirrors at an angle, or prisms to enable the light vfrom the neon tube to pass through the apertures in it, the neon tube itself being so situated as to be outside the solid angle made by the image beams.
  • I may produce the received image by Vcausing a spot of light with an attendant moving screen to be placed within the cone of the light beams, the moving screen upon which the spot is projected being so arranged with perforations that as it revolves, the image beams pass freely throughit at all times.
  • a mirror-drum may be used to project a point of light on to this screen, the two scanning devices and the screen being so arranged that the screen does not interfere with the scanning beams.
  • va screen at an angle across the solid angle made by the image beams, this screen reflecting the visible light and transmitting infra-red light.
  • the observer looking at this screen from an Y angle as properly arranged, looks at the reflection of the image of a television receiver seen on the infra-red screen.
  • the person can be so adjusted that when he is looking directly at the reflected image, he is looking directly into the scanning lens.
  • An ordinary filter possesses this property of relecting visible light to a certain degree, and may be used; or the effect may be enhanced by using a partly silvered screen, so long as the opacity of the Yscreen is not such as to destroy the eiect of the transmitting beam.
  • Figure 2 is a plan of Figure 1, showing the rays of both scanning beams, Y
  • Figure 3 is a plan of a further embodiment of the invention.
  • Figure V4 shows a perspective view of yet another embodiment of the present invention
  • Figure 5 shows a further embodiment of the present invention in which a single mirror drum scanning and reconstituting device is used in place of the pair of drums shown in Figure 4.
  • Vthis light spot is systematically kpassed over the observer, and part of the diffused light is receivedon the cells 'I in the usual Way.
  • a lterV I5 which transmits chiefly or exclusively the invisible component of the light.
  • This iilter has the side towards the observer highly polished and is set at an angle of to a scanning disc IIIV which is mounted parallel rto the drum and maybe on the same shaft.
  • Behind the disc I4 is an electric Vglow lamp 8, the light from which is reflected by the polished surfacesv of the filter I5 towards the vobserver 6.
  • This glow lamp is modulated by the image signal from the distant station so thatV the observer 6, in looking at his co-operator, is caused to look directly into the invisible scanning beam as before.
  • which may be for example, the well known hot cathode type of lamp
  • isimodulated by the image signals from thedis- Ytant-station.
  • . is Varrangedby means YVof anappropriate system of gears, so that during "the;period that a clear aperture is Vin line with and the drums, light from the vdrum I5 scans one strip of the image of the Thus the observer E sees an image of as before,'in'gazing at this imagehe is also looking :straight into the spot-light scanning beam.
  • strips from the images of the two operators may be transmitted alternately by appropriate masking and these intercalated signals may be transmitted over a single channel in the manner described in my co-pending British application No. 6712/31.
  • the same method of scanning may be effected by the embodiments illustrated in the other drawings.
  • this end may be attained by making the spot-light traverse area twice the height of the observer to be scanned, by masking the unused part of the scan and receiving and reconstituting the image signal from the distant station during the intervals in the spot-light scanning.
  • are preferably covered with iilters which are opaque or substantially opaque to radiation in the visible portion of the spectrum of the arc. Radiation diffused from the exposed surface of the subject 6 becomes incident upon sensitive cells 1 and becomes operative in transmitting signals by way of Aan amplifying system 38 to a line or channel of communication 39.
  • an additional aperture 22 having a small reflector 23, co-operating therewith to pass light from a glow discharge lamp 8
  • in the direction of the lens I9I and thence to the mirror-drum
  • , 23 are arranged to lie in a plane at right angles to the axis of the drum
  • , 22 is so chosen that the image forming beams strike the coverings of the apertures I8, while the scanning beams pass through the filters of the apertures
  • from the lens IQI A' is such that an image :of the said crater is brought sharplyto focus inthe plane o'f the disc 52, while the distance of the aperture .2
  • .9I is such that an image of theaper- ⁇ ture 2
  • may be regarded as the source of ⁇ .light for scanning the object, and a condenser-lens system may be employed to concentrate light vfrom an varc or other intrinsic source thereon.
  • the extent of the field of View on the disc is limited by means of a mask as indicated ,by the rectangle 31.
  • I may use a single line or channel of .com-
  • munication for carrying two-way television ⁇ si'- nals in a system according to the present invention by using different carrier frequencies according to practice well known in the art of telegraphy and telephony, for the signals proceeding from each of the co-operating stations.
  • scanning beam is equally applicable to both floodlight and spotlight methods of television transmission.
  • the scanning beam which may be of visible or invisible radiation, are those proceeding from the scanning device in the direction of and impinging upon the object, and serving to dene at any instant that portion of the object of which the diffusiVity-value for the particular kind of radiation employed is integrated (over the elemental area on which the radiation impinges at that instant) by light sensitive devices adapted to receive directly part of the diffused radiation.
  • the scanning-beams are those rays of the flood-radiation (diffused from that elemental area of 'the object which at any one instant in the conjugate focus or hypothetical image of the photocell aperture or its equivalent; which lie between the object and the light-transmitting devices of the scanning means.
  • the scanning beams are subjective, and are the rays selected by the scanning means at any instant for conveyance to the light sensitive device.
  • a television apparatus for the simultaneous transmission and reception of images including a disk formed with a spiral series of scanning apertures, adjacent apertures being respectively for transmitting and reproject, a glow lamp, and means whereby such lamp is caused to project its rays through the reproducing apertures of such disk 2.
  • a television system for simultaneously transmitting and receiving images at different stations including substantially identical apparatus at each station, such apparatus in each instance embracing a disk formed with a spiral series of scanning apertures, adjacent apertures being respectively for transmitting and reproducing purposes,v a light source, Vmeans whereby light rays from such source are Ycaused to pass through the transmitting apertures of such series and to the object which is to be reproduced, ⁇ light sensitive means adjacent such object, aV glow lamp, means whereby such glow lamp is caused to project its rays through the reproducing apertures, the lamp of one unit of apparatus being connected to the light sensitive means of the other unit, and means whereby when the transmitting aperture of one disk is in operative position, the reproducing aperture Yof the other disk will be in similar position.
  • a television apparatus for the simultaneous transmission and reception of images including a disk formed with scanning apertures, a mirror to move in synchronism With such disk and including a plurality of reflecting surfaces, a light source embodying rays to be reected by the surfaces of such mirror towards the object to'be reproduced for scanning the same, a further and angularly disposed mirror interposed between such reiiecting mirrors and such object, such latter mirror having light filtering characteristics,V a glow lamp disposed adjacent such mirror and so that its rays will pass through the apertures of such disk and be reflected by the surfaces of the mirror towards the object, and a light sensitive means adjacent such object.

Landscapes

  • Engineering & Computer Science (AREA)
  • Multimedia (AREA)
  • Signal Processing (AREA)
  • Video Image Reproduction Devices For Color Tv Systems (AREA)
  • Optical Elements Other Than Lenses (AREA)
  • Image Input (AREA)
  • Facsimile Scanning Arrangements (AREA)
US574114A 1930-11-12 1931-11-10 Television and like apparatus Expired - Lifetime US2056761A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB34064/30A GB365241A (en) 1930-11-12 1930-11-12 Improvements in or relating to television or like apparatus

Publications (1)

Publication Number Publication Date
US2056761A true US2056761A (en) 1936-10-06

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ID=10360917

Family Applications (1)

Application Number Title Priority Date Filing Date
US574114A Expired - Lifetime US2056761A (en) 1930-11-12 1931-11-10 Television and like apparatus

Country Status (4)

Country Link
US (1) US2056761A (en(2012))
BE (1) BE384059A (en(2012))
FR (1) FR726468A (en(2012))
GB (1) GB365241A (en(2012))

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5202957A (en) * 1990-08-09 1993-04-13 Future Communications Full motion video telephone system

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5202957A (en) * 1990-08-09 1993-04-13 Future Communications Full motion video telephone system

Also Published As

Publication number Publication date
GB365241A (en) 1932-01-21
BE384059A (en(2012))
FR726468A (fr) 1932-05-30

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