US3322570A - Photosensitive electrodes and method of making same - Google Patents

Photosensitive electrodes and method of making same Download PDF

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Publication number
US3322570A
US3322570A US281959A US28195963A US3322570A US 3322570 A US3322570 A US 3322570A US 281959 A US281959 A US 281959A US 28195963 A US28195963 A US 28195963A US 3322570 A US3322570 A US 3322570A
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United States
Prior art keywords
layer
photoconductive
photosensitive
electrode
photoconductive material
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Expired - Lifetime
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US281959A
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English (en)
Inventor
Ashikawa Mikio
Umezawa Hideki
Ozawa Kazuo
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Hitachi Ltd
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Hitachi Ltd
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J9/00—Apparatus or processes specially adapted for the manufacture, installation, removal, maintenance of electric discharge tubes, discharge lamps, or parts thereof; Recovery of material from discharge tubes or lamps
    • H01J9/20—Manufacture of screens on or from which an image or pattern is formed, picked up, converted or stored; Applying coatings to the vessel
    • H01J9/233—Manufacture of photoelectric screens or charge-storage screens
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T428/00—Stock material or miscellaneous articles
    • Y10T428/249921—Web or sheet containing structurally defined element or component
    • Y10T428/249953—Composite having voids in a component [e.g., porous, cellular, etc.]
    • Y10T428/249961—With gradual property change within a component

Definitions

  • photosensitive electrodes of the kind described have generally included a composite layer including a lirst and porous layer of photoconductive maaterial vapor-deposited on the electrically conductive substrate in the atmosphere of low pressure gas and a second and solid, glassy layer of photoconductive material vapordeposited on the first layer in vacuum or one comprised of three successively superposed layers including a first and a second solid layer with a porous layer therebetween.
  • Porous layers are characterized by their extremely high electrical resistivity and fast photoresponse but are usually low in photosen-sitivity.
  • solid layers generally have a photosensitivity higher than that of porous layers but are slow in photoresponse and lower in electrical resistivity.
  • the present invention is intended to provide a photosenitive electrode which includes a single-layer apparently easier to form than any multiple composite layer and has characteristics at least compatible to those of any convention-al photosensitive electrode, which has a multiplelayer and to provide a method of making such photosensitive electrode having a single-layer.
  • the vapor deposition of a photoconductive material is performed in a gaseous atmosphere while varying the pressure thereof in a continuous fashion from a high to a low vacuum or vice verse to obtain a photosensitive electrode comprised of a vapor-deposited photoconductive layer varying continuously in porosity through the thickness of the layer.
  • the electrode made according to the present invention includes a photoconductive layer which is apparently a single-layer but has characteristic properties combining the merits of a porous and ya solid iilm.
  • characteristic properties can be controlled with ease by controlling the rate at which the gas pressure is varied.
  • FIGURE 1 illustrates a portion of a pick-up tube employing a photosensitive electrode according to the present invention
  • FIGURE 2 illustrates acharacteristic performance of the photosensitive electrode according to the present invention.
  • FIGURE 1 there is shown a tubular glass envelope 1 and 7at one end of this envelope 1 a photosensitive electrode 2 which according to this invention is hermetically sealed to envelope 1 through a metal ring 6.
  • the photosensitive electrode 2 also serves as a window for the envelope 1 and comprises a transparent substrate 3 ⁇ such as a glass plate having a transparent, electrically conductive layer 4, for example, a tin oxide layer, coated on the inner surface of the substrate 3 and a, single layer 5 0f photoconductive material such as antimony trisuliide, vapor-deposited on said conductive layer 4.
  • a transparent substrate 3 such as a glass plate having a transparent, electrically conductive layer 4, for example, a tin oxide layer, coated on the inner surface of the substrate 3 and a, single layer 5 0f photoconductive material such as antimony trisuliide, vapor-deposited on said conductive layer 4.
  • a metal mesh electrode 7 carried by a metal cylinder 8.
  • a practical example for making the photosensitive electrode according to the present invention is as follows. In this example, it is .assumed that antimony trisulfde is employed as a photoconductive material and argon as an ambient gas.
  • a substrate made of glass plate carrying a transparent electrically conductive layer on one surface of said glass plate and antimony trisuliide being contained in a Crucible is rst placed in a vacuum evaporation unit. Then the unit is evacuated and the Crucible is heated to evaporate -antimony trisulide. The time requirement for the vapor deposition of antimony trisullide is measured in advance, which is usually a few minutes.
  • the opening of the gas valve in the argon gas inlet se-ction is positioned and the throttle in the gas inlet conduit is set in accordance with the time requirement.
  • the argon gas inlet section is set up so that the pressure in the evaporation unit is varied from 104' mm. Hg to 10-l mm. Hg in tive minutes.
  • the layer va-pordeposited on the substrate will have a porosity linearly varying through the thickness of the layer, ranging from an extremely compact solid structure obtained under the pressure of l0*5 mm. Hg. to a porous structure obtained under the pressure of l0*1 mm. Hg.
  • FIGURE 2 One example of the characteristic performance of the photosensitive electrode 4is illustrated in FIGURE 2.
  • the illustration represents the so-called light transfer characteristics of Vindicon tubes, which clearly expresses the sensitivity of the tubes.
  • the abscissa represents the intensity of illumination on the surface of the photosensitive electrode while the ordinate represents the magnitude of the signal output current of the Vidicon, -both in a logarithmic scale.
  • the signal output current has been determined for a predetermined dark current of 0.02 na. for each Vidicon.
  • lines 1, 2 and 3 illustrate the characteristics of respective Vidicons employing a photosensitive electrode of the present invention, one including a three-layer, layer, and one including a two-layer, layer, respectively.
  • ⁇ it is generally considered that the best way of cpmparing the sensitivity between Vidicons is to determine the intensity of illumination on the surface of the photosensitive electrode as required to allow the Vidicon to provide a signal output of a specific current value.
  • the values of the intensity of illumination determined from lines 1, 2 and 3 for ya signal output current of 0.1 laa. are 0.35 lux, 2.8 lux and 18 lux, respectively.
  • the light requirement of the photosensitive electrode made according to the present invention is about one-eight of tha-t of the threelayer, layer electrode and about 1/,1 of that of the twolayer, layer electrode, that is, the inventive photosensitive electrode has a highly improved sensitivity, which is about eight times and fty-one times as high as that of the threeand two-layer film electrodes, respectively.
  • the variation in porosity of the photoconductive layer thr-ough its thickness can be otherwise controlled by varying the gas pressure in the evaporation unit at an appropriate rate instead of varyin g the pressure in proportion to time.
  • a photoconductive layer having a porosity varying through its thickness in any desired manner can be o-btained by controlling the variation in pressure of the gasous atmosphere within the evaporation unit. Accordingly, in the practice of the invention, the relationship between the photosensitive electrode performance and the manufacturing method can be determined easily compared with the case of conventional photosensitive electrode having twoor threecomposite layers of photoconductive material. Thus it is possible to make photosensitive electrodes which are improved in performance over conventional ones.
  • a photosensitive electrode comprising a transparent substrate having a transparent, electrically conductive layer on one surface thereof and a single layer of photoconductive material disposed on said electrically conductive layer, said photoconductive material having a porosity which varies continuously from the solid state to the porous 4state or from the porous state to the solid state through the thickness of the photoconductive layer.
  • said photoconductive layer is .antimony trisultide.
  • a method of making a photoconductive electrode which comprises placing a transparent substrate having a transparent, electrically conductive layer in an evaporation unit with a photoconductive material, and heating the photoconductive material to evaporate it while varying the pressure in said evaporation unit gradually from a rst predetermined value to a second predetermined value which is higher or lower than said first predetermined value, :to cause deposition of a single layer of photoconductive material on the surface of said electrically conductive layer, said photoconductive material having a porosity varying continuously through the thickness of the photoconductive layer.

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  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Formation Of Various Coating Films On Cathode Ray Tubes And Lamps (AREA)
  • Image-Pickup Tubes, Image-Amplification Tubes, And Storage Tubes (AREA)
  • Photoreceptors In Electrophotography (AREA)
US281959A 1962-05-25 1963-05-21 Photosensitive electrodes and method of making same Expired - Lifetime US3322570A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP2091762 1962-05-25

Publications (1)

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US3322570A true US3322570A (en) 1967-05-30

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US281959A Expired - Lifetime US3322570A (en) 1962-05-25 1963-05-21 Photosensitive electrodes and method of making same

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US (1) US3322570A (enrdf_load_stackoverflow)
DE (1) DE1242262B (enrdf_load_stackoverflow)
GB (1) GB1008986A (enrdf_load_stackoverflow)
NL (1) NL293135A (enrdf_load_stackoverflow)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB8324223D0 (en) * 1983-09-09 1983-10-12 Tipmaster Ltd Floor structure

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2967962A (en) * 1958-01-06 1961-01-10 English Electric Valve Co Ltd Television and like camera tubes
US3015746A (en) * 1955-02-15 1962-01-02 Emi Ltd Electron discharge devices employing photo-conductive target electrodes

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
NL204653A (enrdf_load_stackoverflow) * 1955-02-18

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3015746A (en) * 1955-02-15 1962-01-02 Emi Ltd Electron discharge devices employing photo-conductive target electrodes
US2967962A (en) * 1958-01-06 1961-01-10 English Electric Valve Co Ltd Television and like camera tubes

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Publication number Publication date
NL293135A (enrdf_load_stackoverflow) 1900-01-01
DE1242262B (de) 1967-06-15
GB1008986A (en) 1965-11-03

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