US3440478A - Image storage device - Google Patents

Image storage device Download PDF

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Publication number
US3440478A
US3440478A US476529A US3440478DA US3440478A US 3440478 A US3440478 A US 3440478A US 476529 A US476529 A US 476529A US 3440478D A US3440478D A US 3440478DA US 3440478 A US3440478 A US 3440478A
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Prior art keywords
target element
electrons
mesh
potential
pattern
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US476529A
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English (en)
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Martin Green
Alvin H Boerio
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Westinghouse Electric Corp
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Westinghouse Electric Corp
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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
    • H01J31/58—Tubes for storage of image or information pattern or for conversion of definition of television or like images, i.e. having electrical input and electrical output
    • H01J31/60—Tubes for storage of image or information pattern or for conversion of definition of television or like images, i.e. having electrical input and electrical output having means for deflecting, either selectively or sequentially, an electron ray on to separate surface elements of the screen
    • H01J31/62—Tubes for storage of image or information pattern or for conversion of definition of television or like images, i.e. having electrical input and electrical output having means for deflecting, either selectively or sequentially, an electron ray on to separate surface elements of the screen with separate reading and writing rays
    • H01J31/64—Tubes for storage of image or information pattern or for conversion of definition of television or like images, i.e. having electrical input and electrical output having means for deflecting, either selectively or sequentially, an electron ray on to separate surface elements of the screen with separate reading and writing rays on opposite sides of screen, e.g. for conversion of definition
    • 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
    • H01J29/10—Screens on or from which an image or pattern is formed, picked up, converted or stored
    • H01J29/36—Photoelectric screens; Charge-storage screens
    • H01J29/39—Charge-storage screens
    • H01J29/44—Charge-storage screens exhibiting internal electric effects caused by particle radiation, e.g. bombardment-induced conductivity
    • 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
    • H01J31/34—Image pick-up tubes having an input of visible light and electric output with electron ray scanning the image screen having regulation of screen potential at cathode potential, e.g. orthicon
    • H01J31/36—Tubes with image amplification section, e.g. image-orthicon

Definitions

  • a photocathode element is positioned on one side of the target element and an electron gun is disposed on the other.
  • the photocathode element emits in response to a light scene a corresponding electron image onto the target element; as a result, a charge pattern is established on the target element corresponding to the light scene.
  • the electron gun positioned on the other side of the target element provides an electron beam of low velocity to scan the target element and to thereby derive an output signal corresponding to the pattern of charges distributed upon the target element.
  • a writing electron gun is substituted for the photocathode element.
  • the information to be placed upon the target element is scanned across one surface of the target element in a given pattern to thereby provide a pattern of charges upon the target element. Due to the insulating or dielectric nature of the target element, the charge pattern remains upon the target element for an extended period of time. During this time the target element is scanned by a second beam of electrons to thereby provide an output signal corresponding to the pattern of charges.
  • the output signals are typically produced by a different scanning pattern than that by which the charge pattern was established on the target element by the writing electron gun.
  • This particular type of image device is commonly known as a scan converter.
  • Another object of this invention is to provide a new and improved image storage device having a high gain target element therein capable of providing many copies of the output signal from a single stored pattern.
  • a further object of this invention is to provide a new and improved image storage device incorporating therein a target element capable of integrating the input signal over an extended period of time and of rapidly discharging the resultant charge pattern.
  • Another object of this invention is to provide a new and improved image storage device having a target element therein upon which the reading and writing by electron beams can be performed simultaneously.
  • a still further object of this invention is to provide an image storage device having a target element therein 3,440,478 Patented Apr. 22, 1969 ice of increased dimensions thereby improving the resolution of this device.
  • an image storage device including a target element for storing a pattern of charges, means for directing an electron beam modulated with input signals onto the target element, and means for directing a second electron beam into the target element to thereby derive an output signal.
  • the target element includes a plurality of elements made of a porous dielectric storage material having a density of less than 10% of the material in bulk form and a conductive member for supporting the dielectric elements.
  • the elements of dielectric material and the conductive member have portions thereof which are exposed to the electron beam directed thereon to derive an output signal.
  • the dielectric material is disposed as by evaporation onto a fine mesh to thereby provide a target element having exposed on one side thereof portions of the electrically conductive mesh and a plurality of exposed portions of dielectric material.
  • the target element is operated so that the side of the target element having exposed portions of dielectric and conductive material is scanned by a low velocity electron beam to establish a negative potential on the exposed portions of the dielectric material.
  • a pattern of charges corresponding to the input signal is then disposed thereon by bombarding the target element with a beam of electrons accelerated onto the target element at a voltage suilicient to produce a .secondary electron generation gain of greater than unity in the dielectric material. Due to the porous nature of the dielectric material, the electrons generated within the voids of the dielectric material are collected by the conductive material which is integrally associated with the target element to thereby drive portions of the dielectric material more positively.
  • the portions of the dielectric material exposed to the reading electron beam are driven from a negative to a more positive, though still negative, potential; such a process allows the target element to utilize the inherently high gain of the porous dielectric material.
  • the exposed dielectric elements are more negative than the exposed portions ⁇ of the conductive member, and as a result the reading electron beam will be attracted to the conductive member in accordance with the charges established upon the exposed dielectric portion. It is noted that the reading electron beam does not land upon the dielectric portions and as a result the charge pattern is not erased and the readout process may be repeated many times.
  • FIGURE l is an elevational view in section, schematically representing an image storage device in accordance with the teachings of this invention.
  • FIG. 2 is an elevational view in section, schematically representing an alternative embodiment of an image storage device in accordance with the teachings of this invention
  • FIG. 3 is an enlarged elevational View in section illustrating the storage target element as utilized in the devices for FIGURES l and 2;
  • FIG. 4 is a graphical representation of the conditions upon the target element during the operation of the device shown in FIG. l.
  • the image storage device 10 comprises an envelope 12 including a face plate 14 enclosing one end of the envelope 12 and made of a suitable material transmissive to the desired scene radiation.
  • An electron gun 18 is provided at the opposite end of the envelope l2 for generating and forming a pencil-type electron beam which is directed onto a storage target element or electrode 20.
  • the storage target element 20 is positioned between the electron gun 18 and the photocathode element 15. Between the storage target element 20 and the photocathode element 15, there is provided a plurality of electrodes illustrated as 42 and 44 with suitable potential provided thereon for accelerating and focusing the photoelectrons emitted from the photocathode element 15 onto the storage target element 20. Positioned between the storage target element 20 and the electron gun 18, there is provided a grid member 22 made of a suitable electrically conductive material such as nickel which is located at a distance of about .125 inch from the surface of the storage target element 20.
  • the electron gun 18 is of any suitable type for producing a low velocity pencil-like electron beam to be scanned over the surface of the storage target element 20.
  • the electron gun 18 may consist of a cathode element 30, a control grid 32 and an accelerating grid 34.
  • the gun electrodes 30, 32, and 34 along with an anode electrode 36, which may be a coating of electrically conductive material disposed upon the interior surface of the envelope 12, provide a focused electron beam which is directed onto the storage target element 20.
  • Deflection means 38 illustrated as an electromagnetic coil is provided about the envelope 12 for deflection of the electron beam and by application of suitable currents, scans the electron beam over the surface of the target element 20 in a conventional manner.
  • a focusing means illustrated as an electromagnetic coil 40 is also provided about the envelope 12 to provide additional focusing of electron beam from the electron gun 18 onto the storage target element 20 as well as for focusing the electron beam emitted from the photocathode element 15 onto the other side of the storage target element 20.
  • the storage target element 20 is supported upon a ring 24 made of a suitable material such as Kovar alloy (Westinghouse Electric Corporation trademark for an alloy of nickel, iron and cobalt). Further, the storage target element 20 is comprised of a very fine mesh 26 which is made of a suitable electrically conductive material such as copper or nickel and which is secured to the ring 24 by an annular support member 29 which may be spot welded to the ring 24.
  • the mesh 26 may be of the Woven type or be made from a solid sheet which has been etched to provide a perforate structure. In an illustrative embodiment of the target element 20, the mesh 26 has at least 750 holes per inch and an open area of from 50 to 60%.
  • a mesh of these parameters has a wire diameter in the order of 6 microns.
  • a layer 28 of a material exhibiting secondary emission properties is then deposited directly 4 onto the mesh 26. Suitable materials which exhibit this property include potassium chloride, barium uoride, sodium bromide, and magnesium oxide.
  • the layer 28 is of a spongy or porous consistency having a density of less than 10% of the density of the storage material in its normal state.
  • the porous layer 28 is formed by the evaporation of the secondary emissive material onto the mesh 26.
  • the material to be deposited is heated to its evaporation temperature in the presence of an inert atmosphere, for example helium or argon.
  • the evaporation takes place at a distance in the order of a few inches in an atmospheric pressure of about .5 to 5 millimeters of mercury. It is an important aspect of this invention as will be explained later that portions or elements of the dielectric material are disposed in the interstices of the mesh 26.
  • these portions of the dielectric material and portions of the mesh 26 present exposed surfaces which are disposed substantially in the same plane. During the evaporation, particles of the dielectric material, though smaller than the holes in the mesh, will deposit and grow sideways from the wires of the mesh 26 to thereby cover the entire area of the mesh and provide a continuous layer of the dielectric material. Further, those portions of the conductive mesh 26 directly abutting a back-plate will not be coated with the dielectric material in accordance with the teachings of this invention.
  • the mesh 26 has from 750 to 1000 holes per inch and an open area from to 60%.
  • the particles of dielectric material have a diameter in a range of l to 2 microns and the layer 28 has a density in the range of from l to 2% of the bulk density of the material being deposited and a total thickness of from 5 to 40 microns.
  • One of the significant properties of the target element 20 is that gains in the order of 100 have been readily achieved by elements that have been constructed in accordance with the above description.
  • an external connection is made from the conductive mesh 26 of the target element 20 to an impedance 48 which is in turn connected to a switching means 54.
  • the switching means 54 may be connected through either of the potential sources 50 ⁇ and 52 to ground.
  • an output signal may be derived across the impedance 48 and directed through a capacitance 56.
  • the opeartion of the image storage device 10 as shown in FIG. 1 requires the performance of a three-part cycle.
  • the three steps of this cycle include (1) erasing and/0r priming, (2) a writing step, and (3) a reading step;
  • the conductive mesh 26 of the storage target elementment 20 is set at a potential with respect to that of the cathode element 30 of approximately 10 volts positive. This is accomplished by connecting the conductive mesh 26 to the potential source 52 as by the switching means 54 (i.e. position l). Electrons emitted form the cathode element 30, which is connected to ground, are accelerated by the voltage placed upon the conductive mesh 26 and drive the surface of the porous layer 28 exposed to the electrons emitted by the cathode element 30 to the potential of the cathode element 30 ⁇ (i.e. ground potential).
  • the switching means 54 is disposed in a second position where the conductive mesh 26 of the target element 20 is connected to the potential source 50 which is approximately 2 volts positive with respect to ground. It may be understood that due to the capacitive action between the conductive mesh 26 and the surface of the porous layer 28 that the surface of the layer 28 disposed in the interstices of the mesh 28 is set at approximately -8 volts with respect to ground.
  • the radiation emitted from a scene 46 is focused upon the photocathods element 15 and photoelectrons are emitted from each portion of the coating ⁇ 16 corresponding to the amount of light directed thereon.
  • the photoelectrons are focused as by electrodes 42 and 44 and are accelerated with a suicient high energy of about 5 to kev. onto the target element 20.
  • the acceleration voltage is of such a value that substantially all the primary electrons from the photocathode element completely penetrate the porous layer 28 but do not substantially pass on through the structure.
  • the primary electrons from the photocathode element 15 create a number of low energy electrons within the voids of the layer 28 orders of magnitude higher than the number of incident or primary electrons.
  • the number of secondary electrons generated is about for each primary electron incident upon the target element 20.
  • the secondary electrons generated within the layer 28 are attracted by the positive potential applied to the conductive mesh 26. It is an important aspect of this invention that the conduction of electrons through the layer 28 takes place through the voids of the porous layer 28 to the mesh 26 which is an integral part of the storage target element 20.
  • This type of electron conduction is known as secondary electron conduction (SEC) in contradistinction to the electron conduction taking place through the solid portions of a material.
  • SEC secondary electron conduction
  • those portions of the layer 28 which have been bombarded with photoelectrons will be charged in a positive direction, though still negative with respect to ground, to a potential of approximately 4 volts negative. Those portions of the layer 28 which had not been bombarded with photoelectrons will remain at a potential of approximately 8 volts negative with respect to ground.
  • the intensity of the photoelectron bombardment emitted from the photocathode element 15 will vary as to the intensity of the light focused upon the element 15.
  • the level of charge placed upon the layer 28 will correspond to the intensity of the incident photoelectrons; as a result, various portions of the layer 28 may vary between 8 volts negative and 4 volts negative depending on the intensity of the incident photoelectrons.
  • the image storage device 10 ⁇ is set to derive an output signal. This may be accomplished by disposing the switching means 54 in its second position so that the electrically conductive mesh 26 is connected through the impedance 48 through the potential source 50y of approximately 2 volts positive with respect to ground. As explained above, there has been established upon the surface of the layer 28 a pattern of charges whose potential varies between 4 volts negative and 8 volts negative with respect ground in accordance with scene 46. As shown in FIGURE 3, equal potential surfaces are distributed from the surface of the dielectric storage layer 28 in accordance with this pattern of charges. It is understood that the charge of 8 volts negative stored upon the layer 28 represents an absence of a signal or a black input signal being stored upon the target element 20, whereas a charge of 4 volts negative represents a white input signal.
  • the negative equal potential surfaces emanating from the layer 28 tend to cut down the area through which electrons emitted from the electron gun 18 can be directed onto the conductive mesh 26.
  • the equal potential surfaces spread and overlap to further prevent the landing of electrons upon the conductive mesh 26.
  • the negative equal potential surfaces are so distributed from the surface of layer 28 ⁇ to form passageways to the exposed portions of the mesh 26.
  • the electrons emitted by the cathode element 30l are focused and accelerated as by electrodes 34 and 36 and are deflected as by means 38 across the surface of the storage target element 20.
  • a portion of the electron beam emitted by the electron gun 18 is allowed to land upon the conductive mesh 26 to thereby provide an output signal across the impedance 48.
  • the reading beam landing on the conductive mesh is correspondingly decreased.
  • FIG. 4 there is shown a series of graphs indicating the percentage of electron beam current collected by the mesh 26 as a function of the potential -disposed upon the dielectric layer 28 with respect to ground (i.e., the potential of the cathode element), and the potential established upon the conductive mesh 2:6 with respect to ground (i.e., the potential of the cathode element).
  • FIG. 4 In the exemplary method of operation where a potential of 2 volts positive with respect to ground has been established on the conductive mesh 28, FIG.
  • the reading beam current directed upon the mesh 28 is inversely related to the negative voltage charge established upon the layer 28 and directly related to the intensity of the electron image generated by the photocathode element 25 and the radiation emitted by the scene 46.
  • an output signal is derived ⁇ without erasing the pattern of charges established upon the porous layer 28 of the storage target element 20.
  • the output signal is derived as the conductive mesh 28 collects electrons and a potential is developed across the impedance 48. It is specifically noted that the surface of the porous layer 28 is established at a negative potential whereas the conductive mesh 26 is set at a positive potential to attract the electrons. Therefore, the electrons emitted by the cathode element 30 cannot land upon the surface of the layer 28 while it is disposed negatively and are in turn collected upon the positively disposed conductive mesh 26.
  • the surface of this layer as explained above with regard to the priming of the target element would be established at the potential of the cathode element and a pattern of charges would thereby be erased.
  • the surface of the porous layer 28 is disposed at a negative potential thereby preventing the bombardment of electrons and allowing a multicopy readout from the storage type element 2li.
  • the exposed surfaces of the conductive mesh 26 and the layer 28 of dielectric material should be substantially the same plane. More specifically, these surfaces should not be displaced from each other more than one-half the width of the portions of dielectric material disposed in the interstices of the mesh 26. 1f this condition is substantially not met, the electrons emitted from the electron gun 18 will not be eiciently collected by the mesh 26 and a distorted attenuated output signal will be derived.
  • the image storage tube 6 includes an enclosed tubular envelope 61 having disposed therein at one end a reading electron gun 62 comprised of a cathode elef ment 64, a control electrode 66 and an accelerating electrode 68 and an anode element 70 which may be formed as a coating upon the interior surface of the envelope 61.
  • a i writing electron gun 74 including a cathode element 76, a control electrode 78, an accelerating electrode and an anode element 82 which may be disposed as a coating upon the interior surface of the envelope 61.
  • a storage target element 20 as described above with regard to FIG. 3 is disposed between the reading and writing electron guns 62 and 74. More specifically, the exposed portions of the conductive mesh 26 are disposed toward the reading electron gun 62. Further, a grid member 86 is disposed in a spaced relationship from the storage target element 20 in order t0 normalize the path of the electrons emitted by the cathode element 64 as they land upon the surface of the storage target element 20.
  • a defiection means 72 shown as an electromagnetic coil 72 is disposed about the envelope 61 so as to deect electron beams emitted by the reading electron gun 62 across the surface of each storage target element 20.
  • a deliection means 84 shown as an electromagnetic coil is disposed about the envelope 61 in order to deflect the electron beam as emitted by the cathode element 76 across the opposite surface of the storage target element 20.
  • a beam of electrons emitted by the cathode element 76 of the writing electron gun 74 is accelerated with approximately 6 kev. onto the surface of storage target element 20.
  • An input signal is disposed upon the control electrode 78 to thereby modulate the writing electron beam which is scanned by means 84 over the surface of the storage target element 20 in a typical television pattern.
  • secondary electrons are generated within the voids of the porous layer 28 and are conducted to the conductive mesh 26.
  • a positive voltage of approximately l0 volts is applied to conductive mesh 26 to attract the generated secondary electrons. Due to the aggregate loss of electrons, portions of the surface of the porous layer 28 are drawn towards the potential of the conductive mesh 26.
  • the surface of the porous layer 28 will have a pattern of positive charges corresponding to the input signal disposed upon the control electrode 78.
  • the reading electron beam as emitted from the cathode element 64 is scanned over the surface of the storage target element 20 as by means 72.
  • the reading electron beam is attracted to the more positively charge portion of the porous layer 28 the incident reading electron beam tends to charge the surface 20 toward the potential of the cathode element 64 or ground potential.
  • a charge is induced across a minute portion of the porous layer 28 to the conductive mesh 26 to provide an output seignal which is proportional to the potential stored upon the surface of the porous layer 28.
  • an output signal may be derived representing the pattern of charges disposed upon the storage target element 20 by the writing electron gun 74 and at the same time, the pattern of charges is erased as the surface of the porous layer 28 is driven towards the cathode or ground potential. Due to this capability of rapid erasure, the Writing electron beam may be secanned across the storage target element 20 at one scan rate or pattern whereas the reading electron beam may be scanned at a second rate or pattern which is different from the first.
  • the reading and Writing operations may be conducted simultaneously with each other. It is noted that due to the high inherent gain (i.e., at least ten) of the storage target element 20 that the current collected by the conductive mesh 26 due to the capacitive discharge of the charge pattern under the bombardment of the reading electron beam is in the order of several magnitudes larger than the electron beam current originating from the cathode element 76. Thus, the output signal is primarily related to the reading beam current and is substantially independent of the Writing electron beam current.
  • the emitted secondary electrons tend to be attracted by the positive potentials applied to various electrodes on the reading side of the target element. Due to the additional loss of electrons, the surface of the target element is driven more positively and may assume the potential of the aforementioned electrodes. Typically, these electrodes are maintained at several hundred volts positive with respect to the target elements and may drive the target element to a potential at which the internal field created within the target element physically destroys this element.
  • secondary electrons are substantially prevented from escaping from the target element and no transmission secondary electron emission takes place. This is principally due to the fact that the voltage applied to the conductive mesh establishes potential surfaces which retard the escape of secondary electrons from the target element.
  • the image storage device may write and also erase the pattern of charges upon the target element with but a single scan of the reading electron beam across surfaces of the storage target element.
  • the capability of quickly writing and erasing is due to the nature of the electron conduction that takes place Within the porous layer of the storage target element; specifically, the electrons are conducted through the voids of the porous layer as opposed to solid state conduction which is inherently slower.
  • An electron discharge device comprising a storage target electrode, said storage target electrode including a plurality of storage elements of a porous material having a density of less than 10% of said material in bulk form, and an electrically conductive member, said storage target electrode having at least one surface With portions of said storage elements and said member exposed; means for directing a writing electron beam modulated with a signal upon said storage target electrode to generate within said storage elements secondary electrons to thereby establish a charge pattern whose distribution is determined in accordance with said signal; and means for directing a reading electron beam upon said one surface of said storage target element to derive an output signal corresponding to said pattern of charges.
  • An electron discharge device comprising a storage target electrode, said storage target electrode including a plurality of elements made of a porous material having a density less than 10% of the material in bulk form, said material exhibiting the property of generating electrons within said elements in response to electron bombardment and conducting electrons through the voids of said porous material, and an electrically conductive member, said elements and said member each presenting upon one surface of said storage target electrode exposed areas substantially disposed in a plane; means for directing a writing electron beam modulated with a signal at said storage target electrode to generate within said elements secondary electrons which are collected by said conductive member to establish a charge pattern whose distribution is determined in accordance with said signal; and means for directing a reading electron beam upon said one surface to derive an output signal corresponding to said charge pattern.
  • An electron discharge device comprising a storage target electrode, said storage target electrode including a mesh of an electrically conductive material, and a porous material having a density of less than 10% of said material in bulk form deposited in the interstices of said mesh, said material having the property of generating secondary electrons within said porous material in response to electron bombardment and of conducting electrons through the voids of said porous material, said storage target electrode having at least one surface thereof with exposed portions of said mesh and said porous material disposed substantially in a plane; means for directing a Writing electron beam modulated with input signals upon said storage target electrode to generate within said porous material secondary electrons which are collected by said mesh to establish a pattern of charges whose distribution is determined in accordance with said input signals; and means for directing a reading electron beam toward said one surface to said storage target electrode to derive output signals corresponding to said pattern of charges.
  • An image tube for storing an input signal corresponding to a viewed scene and repetitively providing an output signal corresponding to said input signal, said image tube comprising a storage target electrode including a mesh of an electrically conductive material, and a porous lmaterial having a density of less than 10% of said porous material in bulk form deposited in the interstices of said mesh, said material having the property of generating secondary electrons within said porous material in response to electron bombardment and of conducting electrons through the voids of said material, said storage target electrode having a surface with exposed portions of said material and said mesh disposed substantially in a plane; a photocathode element for directing an electron image in accordance with said scene upon said storage target electrode to generate Within said porous material secondary electrons which are collected by said mesh to establish a charge pattern whose distribution is determined in accordance with said electron image; and an electron gun for repetitively scanning an electron beam upon said surface of said storage target electrode to derive said output signal corresponding to said charge pattern.
  • a storage target electrode including a mesh of an
  • a scan converter tube comprising a storage target electrode, said storage target electrode including a mesh of an electrically conductive material and a porous material having a density of less than 10% of said porous material in bulk form deposited in the interstices of said mesh, said porous material having the property of generating secondary electrons within said porous material in response to electron bombardment and of conducting electrons through the voids of said porous material, said storage target electrode having at least one surface with exposed portions of said porous material and said mesh disposed substantially in a plane; an electron gun for directing an electron beam modulated with input signals upon said storage target electrode to generate within said porous materal secondary electrons which are collected by said mesh to establish a pattern of charges whose distribution is determined in accordance with said input signals; and a second electron gun disposed on the opposite side of said storage target electrode for directing an electron beam upon said one surface of said storage target electrode to derive an output signal corresponding to said pattern of charges.

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  • Image-Pickup Tubes, Image-Amplification Tubes, And Storage Tubes (AREA)
US476529A 1965-08-02 1965-08-02 Image storage device Expired - Lifetime US3440478A (en)

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GB (1) GB1156670A (en, 2012)
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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2896110A (en) * 1956-07-02 1959-07-21 Hansen Siegfried Feedback circuits for storage tubes
US3213316A (en) * 1962-12-03 1965-10-19 Westinghouse Electric Corp Tube with highly porous target
US3356878A (en) * 1965-08-02 1967-12-05 Hughes Aircraft Co Signal converting cathode ray tube with controllable erasure

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2896110A (en) * 1956-07-02 1959-07-21 Hansen Siegfried Feedback circuits for storage tubes
US3213316A (en) * 1962-12-03 1965-10-19 Westinghouse Electric Corp Tube with highly porous target
US3356878A (en) * 1965-08-02 1967-12-05 Hughes Aircraft Co Signal converting cathode ray tube with controllable erasure

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NL6610085A (en, 2012) 1967-02-03
GB1156670A (en) 1969-07-02

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