US2196130A - Cathode ray picture scanner - Google Patents

Cathode ray picture scanner Download PDF

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Publication number
US2196130A
US2196130A US146990A US14699037A US2196130A US 2196130 A US2196130 A US 2196130A US 146990 A US146990 A US 146990A US 14699037 A US14699037 A US 14699037A US 2196130 A US2196130 A US 2196130A
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US
United States
Prior art keywords
light
cathode ray
scanner
mosaic electrode
mosaic
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
Application number
US146990A
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English (en)
Inventor
Urtel Rudolf
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.)
Telefunken AG
Original Assignee
Telefunken AG
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Telefunken AG filed Critical Telefunken AG
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Publication of US2196130A publication Critical patent/US2196130A/en
Anticipated expiration legal-status Critical
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J29/00—Details of cathode-ray tubes or of electron-beam tubes of the types covered by group H01J31/00
    • H01J29/02—Electrodes; Screens; Mounting, supporting, spacing or insulating thereof
    • H01J29/021—Electrodes; Screens; Mounting, supporting, spacing or insulating thereof arrangements for eliminating interferences in the tube
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N23/00—Cameras or camera modules comprising electronic image sensors; Control thereof
    • H04N23/80—Camera processing pipelines; Components thereof
    • H04N23/81—Camera processing pipelines; Components thereof for suppressing or minimising disturbance in the image signal generation

Definitions

  • This invention relates to cathode ray picture scanners and in particular, to method and means for compensating for disturbances in such tubes which result in irregular brightness distribution at the reproducer of the receiver.
  • the value of the disturbance signal is dependent on the operating conditions of thecathode ray scanner, such as for instance on the average brightness of the image to be transmitted into distance. It follows therefrom that during the telecast it is not possible: to use always the same compensation signal, but the apparatus furnishing the compensation signal must be subsequently adjusted with regard to the variations of the mean brightness, if importance is to be attached to an always exact compensation.
  • a diffuse beam of light rays having the same lum nous density throughout its entire section 40 impinges on the photosensitive surface of they scanner in accordance with the invention.
  • the fluctuations of the total light current impinging on the scanner are proportionately lower than without the said diffuse light. Consequently, the variation in the value of the disturbance signal is likewise smaller than if the time Variation of the preliminary light impinging on the scanner has its cause solely in the variations of the average brightness.
  • the slight residual variations in the value of the disturbance signal can fr thermore be eliminated if the diffuse preliminary light is continuously varied in function ofthe average brightness, such that the total light current impinging on the cathode ray scanner remains constant as to time.
  • the effect of the average brightness upon the disturbance signal is entirely obviated, and hence, during the entire telecast the same setting of the apparatus furnishing the compensation signal can be used without the disturbance signal ap pearing at the receiver side.
  • Fig. 1 shows diagrammatically the non-uniform distribution of illumination at the receiver due to dark-spot disturbances at the scanner;
  • Fig. 2 shows diagrammatically one embodiment of the invention in which diffused light of constant intensity is superimposed on the image illumination on the mosaic electrode;
  • Fig. 3 shows a modification of the embodiment shown in Fig. 2 wherein the intensity of 1 the diffused light is controlled by the average value of the imageillumination while;
  • Fig. 4 shows a modification of the embodiment shown in Figs. '2 and 3 wherein a different method and means of projecting the diffused illumination is provided.
  • item Ill represents the object to be telecast
  • II is an objective projecting an image of the object on a transparent screen surface l2
  • I3 is a cathode ray scanner on whose photosensitive surface M the projection screen I2 is reproduced by means of a further objective IS.
  • the entire projection surface It is illuminated by diffuse light across a dispersion lens I! which light is furnished by the source l6 having constant brightness.
  • the photosensitive surface M of the scanner therefore is impinged by a luminous current composed of a constant component supplied by the lamp l6, and a varying component corresponding to the average brightness of the image of the object ID.
  • the proportionate variations of the entire luminous current obviously are smaller than those of the average image brightness, and therefore, the variations of the disturbance signal are likewise smaller at unchanged setting of the appartus furnishing the compensation signal, than in the hitherto customary operating mode in which the light source 16 was absent.
  • Fig. 3 shows a mode of construction in which the object It is reproduced by means of the objective l5, directly on the photosensitive surface I4 of the scanner I3.
  • a reflecting arrangement for instance an oblique glass plate H3 is inserted which may eventually be adapted. as a semipermeable mirror.
  • the dispersion lens H is provided between the plate It and the lamp l6 again the dispersion lens H is provided
  • the lamp i8 is connected to an amplifier l9 controlled by the photocell 26 which as such determines the average image brightness.
  • the arrangement according to 3 operates l5, increases at first.
  • the current furnished by the photocell 20 and conducted to the amplifier l9 increases.
  • This amplifier is so adapted that its output current and hence, the brightness of the lamp [6 become smaller so that less light arrives from the lamp l6 at the scanner across the reflecting device l8, than at a lower average image brightness.
  • the characteristic of the amplifier I9 is now so set that the total luminous current impinging on the surface I always remains at least approximately constant.
  • FIG. 4 another mode of construction is shown inasmuch as it differs from that according to Fig. 3.
  • the glass plate l8 of Fig. 3 is replaced by a smaller mirror 2
  • the invention can be equally well applied to the transmission of open air scenes or stage scenes as well as for the transmission of films, and in the latter case the application is especially simple when the films are projected by means of a projector equipped with optical com-- pensation means.
  • a cathode ray scanner equipped with a mosaic electrode
  • the method of improving the operation which comprises the steps of projecting light images of objects of varying light intensity to be transmitted upon the mosaic electrode, and simultaneously illuminating the mosaic electrode by a flooding light beam of substantially uniform density over the entire mosaic area and of an intensity which varies inversely with increases in average brilliancy in the light image for maintaining the total illumination upon the mosaic at a predetermined substantially constant value.
  • a cathode ray tube scanner equipped with a mosaic electrode
  • the method of improving the operation which comprises the steps of projecting a light image of an object upon the mosaic electrode, and simultaneously irradiating by a flooding light beam the entire mosaic area with diffused light having constant density of illumination.
  • a cathode ray tube scanner equipped with a mosaic electrode
  • the method of improving the operation which comprises the steps of projecting a light image of an object upon the mosaic electrode, and simultaneously superimposing by a flooding light beam upon the entire mosaic electrode area light of constant intensity and constant density.
  • the method of improving the operation which comprises the steps of projecting a light image of an object upon the mosaic electrode, simultaneously superimposing by a flooding light beam upon the entire mosaic electrode area light of constant intensity and constant density, and regulating the intensity of the flooding light beam in accordance with the average value of illumination of the light image.
  • a cathode ray tube scanner equipped with a mosaic electrode
  • the method of improving the operation which comprises the steps of projectinga light image of an object upon the mosaic electrode, simultaneously superimposing by a flooding light beam upon the entire mosaic electrode area light of constant intensity and constant density, and regulating the intensity of the flooding light beam inversely proportional to the average light value of illumination of the light image.
  • a cathode ray scanner equipped with a mosaic electrode
  • the method of improving the operation which comprises the steps of projecting a light image of an object upon the mosaic electrode, simultaneously superimposing by a flooding light beam upon the entire mosaic area diffused light of constant density, scanning the mosaic to produce distorted signals representative of the illumination of the combined image and diiiused light, and transmitting the produced signals together with signals for compensating for the distortion.
  • a television system comprising a cathode ray tube having a mosaic electrode, means for projecting light images of objects of varying light intensity to be transmitted upon the mosaic electrode, and optical means including a flooding light beam of uniform density projected over the entire mosaic electrode area for simultaneously maintaining the total illumination upon the mosaic at a predetermined substantially constant value.
  • a television system comprising a cathode ray tube having a mosaic electrode, means for projecting a light image of an object upon the mosaic electrode, and optical means including a flooding light beam for simultaneously irradiating the entire mosaic area with diffused light having constant density of illumination.
  • a television system comprising a cathode ray tube having a mosaic electrode, means for projecting a light image of an object upon the mosaic electrode, and flooding light beam means for simultaneously superimposing upon the mosaic electrode area light of constant intensity and constant density.
  • a television system comprising a cathode ray tube having a mosaic electrode, means for projecting a light image of an object upon the mosaic electrode, flooding light beam means for simultaneously superimposing upon the entire mosaic electrode area light of constant intensity and constant density, and means for regulating the intensity in accordance with the average value of illumination of the light image.
  • a television system comprising a cathode ray tube having a mosaic electrode, means for projecting a light image of an object upon the mosaic electrode, flooding light beam means for simultaneously superimposing upon the entire mosaic electrode area light of constant intensity and constant density, and means for regulating the intensity inversely proportional to the average light value of illumination of the light image.
  • a television system comprising a cathode ray tube having a mosaic electrode, means for projecting a ligh image of an object upon the mosaic electrode, flooding light beam means for simultaneously superimposing upon the entire mosaic area difiused light of constant density, means for scanning the mosaic to produce distorted signals representative of the illumination of the combined image and diffused and means for transmitting the produced signals together with signals for compensating for the distortion.

Landscapes

  • Engineering & Computer Science (AREA)
  • Multimedia (AREA)
  • Signal Processing (AREA)
  • Transforming Electric Information Into Light Information (AREA)
  • Projection Apparatus (AREA)
  • Image-Pickup Tubes, Image-Amplification Tubes, And Storage Tubes (AREA)
US146990A 1936-06-10 1937-06-08 Cathode ray picture scanner Expired - Lifetime US2196130A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DET47017D DE705983C (de) 1936-06-10 1936-06-10 Einrichtung zum Vermindern der AEnderungen des Stoersignals bei speichernden Kathodenstrahlbildabtastern

Publications (1)

Publication Number Publication Date
US2196130A true US2196130A (en) 1940-04-02

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ID=6542337

Family Applications (1)

Application Number Title Priority Date Filing Date
US146990A Expired - Lifetime US2196130A (en) 1936-06-10 1937-06-08 Cathode ray picture scanner

Country Status (5)

Country Link
US (1) US2196130A (en:Method)
DE (1) DE705983C (en:Method)
FR (1) FR822731A (en:Method)
GB (1) GB478939A (en:Method)
NL (1) NL49863C (en:Method)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2435963A (en) * 1940-12-13 1948-02-17 Columbia Broadcasting Syst Inc Color television

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2435963A (en) * 1940-12-13 1948-02-17 Columbia Broadcasting Syst Inc Color television

Also Published As

Publication number Publication date
DE705983C (de) 1941-05-15
NL49863C (en:Method) 1941-02-15
FR822731A (fr) 1938-01-06
GB478939A (en) 1938-01-27

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