US3890524A - Photo-conductive target comprising both solid and porous layers - Google Patents

Photo-conductive target comprising both solid and porous layers Download PDF

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Publication number
US3890524A
US3890524A US266708A US26670872A US3890524A US 3890524 A US3890524 A US 3890524A US 266708 A US266708 A US 266708A US 26670872 A US26670872 A US 26670872A US 3890524 A US3890524 A US 3890524A
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United States
Prior art keywords
photo
layers
layer
sub
conductive
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Expired - Lifetime
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US266708A
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English (en)
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Rokuro Watanabe
Mitsuhiro Yoshikawa
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Hitachi Ltd
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Hitachi Ltd
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Priority to US266708A priority Critical patent/US3890524A/en
Priority to GB3029572A priority patent/GB1391953A/en
Priority to FR7223607A priority patent/FR2191255B1/fr
Priority to DE2232171A priority patent/DE2232171C3/de
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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
    • 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
    • H01J29/45—Charge-storage screens exhibiting internal electric effects caused by electromagnetic radiation, e.g. photoconductive screen, photodielectric screen, photovoltaic screen

Definitions

  • 313/65 A different constituent ratio of photo-conductive mate- 2,967.254 1/1961 Forgue a 5 A rial, whereby the photo-sensitivity is increased several Kramer times compared to the prio uart compound photo- 2 2 conductive layer, while also improving the lag characv 0e ze e a.., teristic FOREIGN PATENTS OR APPLICATIONS 1,098,076 1/1968 United Kingdom 313/65 A 15 Clams 7 Drawmg F'gures a O 3- RI 000 $2" s i 0 t a r F; .u 00 Z. 00 0 09 1 000 t 0 ,0; o0 V 3 1 0 s 0 0 q PATENTEDJUN 17 M5 3890. 524
  • the compound photo-conductive. layer usually consists'of a transparent conductive layer formed on a transparent substrate such as a glass plate and a photo-. conductive layer formed on the transparent conductive layer.
  • the photo-conductive layer is usually formed by depositing a photo-conductive material such as a group V VI compound, for example, antimony tri-sulfide with an excess content of antimony (usually containing 74, 76 and 78 weight percent of antimony) or arsenic triselenide.
  • a photo-conductive material such as a group V VI compound, for example, antimony tri-sulfide with an excess content of antimony (usually containing 74, 76 and 78 weight percent of antimony) or arsenic triselenide.
  • the photo-conductive layers formed of these photo-conductive compounds are superior to other types of photo-conductive layers such as those consisting of lead oxide or selenium and selenium compounds, since their dark current and photo-current characteristies with respect to the target voltage are free from saturation, so they are very useful.
  • Japanese Patent Publication No. 271/1962 discloses a structure consisting of an amorphous thin solid layer deposited on the transparent conductive film under vacuum of about 10 Torr, a porous layer deposited on the solid layer in an inert gas atmosphere under low vacuum, and a second solid layer the same as the first one deposited on the porous layer.
  • 12008/1965 discloses another structure, which includes an amorphous intermediate layer deposition formed under an intermediate vacuum degree, for instance l0 Torr, and intervening either between an amorphous porous layer and an amorphous solid layer .or between the porous layer and the transparent conductive material.
  • an amorphous intermediate layer deposition formed under an intermediate vacuum degree, for instance l0 Torr, and intervening either between an amorphous porous layer and an amorphous solid layer .or between the porous layer and the transparent conductive material.
  • the primary object of the invention is to provide a compound photo-sensitive layer and the method of manufacturing the same, which provide for obtaining several times as high photo-sensitivity as that of the prior-art compound photo-conductive layer as well as obtaining improved lag characteristic.
  • a compound photo-conductive layer for use in electron gun type pick-up tubes comprising a transparent conductive film, a first thin amorphous solid layer provided on said conductive layer, a second thin amorphous layer, and a porous layer intervening between said first and second thin amorphous solid layers, allsaid layers con taining a photo-conductive material, at least one of said solid layers having a--multi-layer structure consisting of a plurality of sub-layers with a different ratio of constituents of photo-conductive material.
  • a method of manufacturing a componud photoconductive layer for use in electron gun type pick-up tubes comprising the steps of depositing an evaporated photo-conductive material under high vacuum on a transparent conductive film to form a thin amorphous solid layer, depositing said photo-conductive material in an inert gas atmosphere under low vaccum on said solid layer to form an amorphous porous layer, and forming a second solid layer similar to said firstmentioned solid layer on said porous layer by using the process for forming said first-mentioned solid layer, at least one of said steps of forming said solid layers including sub-steps of depositing antimony tri-sulfide with an antimony content of 74 to 78 weight percent to form a first solid sub-layer, and then depositing on said first sub-layer antimony tri-sulfide with an antimony content greater than that for said first sub-layer under the same vacuum degree as for said first sub-layer, thereby forming a multi-layer structure consisting of a pluralit
  • the invention is based on the finding that by forming at least one of the solid layers and/or intermediate layers constituting the compound photo-conductive layer by laminating a plurality of sub-layers with a different ratio of constituents of photo-conductive material, the
  • photo-sensitivity for the same dark current can be increased several times compared to the prior-art compound photo-conductive layer while providing roughly the same voltage-current characteristics.
  • the photosensitivity and lag characteristic do not run counter to each other, so that itis possible to improve both the characteristics.
  • FIG. 1 is a sectional view showing an example of the television pick-up tube using a compound photoconductive layer according to the invention
  • FIGS. 2 to 5 are fragmentary sectional views, to an enlarged scale, showing examples of the compound photo-conductive layer according to the invention
  • FIG. 6 is a graph showing light transfer characteristics of a compound photo-conductive layer according to the invention and a prior-art compound photoconductive layer.
  • FIG. 7 is a graph showing dark current characteristics of a compound photo-conductive layer according to the invention and a prior-art compound photoconductive layer.
  • reference numeral 1 designates a glass tube envelope, numeral 2 an electron gun, numeral 3 a glass face plate, numeral 4 a transparent conductive layer, and numeral 5 a com- I pound photo-conductive layer.
  • FIG. 2 shows the structure of the compound photoconductive layer. It is obtained by depositing on the transparent conductive layer 4 provided on the glass face plate 3, evaporated antimony tri-sulfide containing 74 percent of antimony under a vacuum of Torr to form a first intermediate amorphous sub-layer m about 200 A thick, depositing on the sub-layer m anti-' mony tri-sulfide with a greater content of antimony than for the sub-layer m namely containing 76 percent of antimony, under the same vacuum degree to form a second intermediate, similarly amorphous sublayer m about 200 A thick, and further depositing thereon antimony tri-sulfide with a still greater antimony content compared to the sub-layers m and m namely containing 78 percent of antimony, under the same vacuum degree to form a third intermediate sublayer m about 200 A thick, thereby forming an intermediate layer m of a multi-layer structure consisting of the sub-layers m m and m over-lapping one upon
  • FIG. 3 shows another example of the compound photo-conductive layer according to the invention. It is obtained by depositing on the transparent conductive layer antimony tri-sulfide with an antimony content of 76 percent under an intermediate vacuum degree of 10 Torr to form an intermediate amorphous layer m of a single layer structure and having a thickness of about 800 A, depositing on the intermediate layer m antimony tri-sulfide with an antimony content of 74 percent in an inert gas atmosphere such as argon or helium gas atmosphere under low vacuum to form an amorphous porous layer P about 2 microns thick, and subsequently depositing on the porous layer P antimony tri-sulfide with an antimony content of 74 percent under a high vacuum degree of 10 Torr to form a first amorphous solid sub-layer S about 1,000 A thick and depositing thereon antimony tri-sulfide with an antimony content, greater than that for the sub-layer S namely 76 percent, under the same vacuum degree to form a second amorphous solid sub-
  • FIG. 4 shows a further example of the compound photo-conductive layer according to the invention.
  • FIG. 5 shows a still further example of the compound photo-conductive layer according to the invention.
  • This example comprises a solid layer S formed on the transparent conductive film 4 and consisting of first and second solid sub-layers S and S a porous layer P having a single layer structure, an intermediate layer m consisting of first and second intermediate sublayers m and "132, and a second solid layer S consisting of first and second solid sub-layers S and S Similar to the preceding examples of FIGS.
  • the content of the photo-conductive material in the individual layers having multi-layer structure is smaller for sublayers nearer to the transparent conductive film 4, that is, it is smaller for the first sub-layer S compared to the second sub-layer S
  • the content is smaller for the first sub-layer in either multi-layer structure layer.
  • the antimony content for the individual layers and sub-layers ranges between 74 and 78 weight percent, while in case of using arsenic tri-selenide the arsenic content for these layers ranges between 41 and 47 weight percent.
  • FIG. 6 shows light transfer characteristics of the compound photo-conductive layer according to the invention and the prior-art compound photo-conductive layer.
  • Curve A represents the characteristic of the layer having the structure shown in FIG. 2 according to the invention
  • curve B represents that of a prior-art layer of the same structure as the FIG. 2 one except that the intermediate layer is of a single layer structure of antimony tri-sulfide with an antimony content of 76 weight percent.
  • FIG. 7 shows dark current characteristics of compound photo-conductive layers according to the invention and of the prior art.
  • the abscissa represents voltage impressed on the transparent conductive film, and the ordinate the dark current value.
  • the solid curve is obtained for asolid layer or intermediate layer of a multi-layer structure according to the invention, and the dashed curve is obtained for a prior-art solid layer of intermediate layer. It will be seen that according to the invention the dark current is extremely reduced, and also non-ohmic characteristics can be obtained.
  • a compound photo-conductive target for use, in electron gun type pick-up tubes comprising a transparent conductive film a first thin amorphous solid layer provided on said conductive film, a second thin amorphous solid layer, and a porous layer intervening between said first and second thin amorphous solid layers, all of said layers being formed of a photo-conductive material selected from the group essentially consisting of antimony trisulfide and arsenic triselenide, at least one of said solid layers having a multi-layer structure consisting of a plurality of sub-layers, the antimony or arsenic content of said photo-conductive material in said sub-layers being greater for sub-layers successively remote from said transparent conductive film.
  • the content of arsenic in the individual layers and sub-layers is in a range between 35 and 50 weight percent.
  • said intermediate layer has a multilayer structure consisting of a plurality of sub-layers formed of a photoconductive material selected from the group essentially consisting of antimony trisulfide and arsenic triselenide the antimony or arsenic content in said photo-conductive compound being greater for the sub-layers successively remote from said transparent conductive film.
  • the content of antimony in the individual layers and sub-layers is in a range between 70 and 80 percent.
  • a compound photo-conductive target having a structure consisting of a transparent conductive film, an amorphous porous layer deposited in an inert gas atmosphere under low vacuum, and an amorphous solid layer deposited under high vacuum and an amorphous intermediate layer deposited in a degree of vacuum intermediate said low vacuum and said high vacuum, all said layers containing a photo-conductive material selected from the group essentially consisting of antimony trisulfide and arsenic triselenide, at least one of said solid layer and said intermediate layer having a multi-layer structure consisting of a plurality of sublayers, the antimony or arsenic content of said photoconductive material in said sub-layers being greater for sub-layers successively remote from said transparent conductive film.
  • a compound photo-conductive target having a structure consisting of a transparent conductive film, an amorphous porous layer deposited in an inert gas atmosphere under low vacuum, and an amorphous intermediate layer deposited in a degree of vacuum intermediate said low vacuum and said high vacuum, all said layers containing a photo-conductive material of the V-VI group of compounds, at least one of said solid layer and said intermediate layer having a multi-layer structure consisting of a plurality of sub-layers, the V- group element content of said photo-conductive material being greater for sub-layers successively remote from said transparent conductive film.
  • a compound photo-conductive target for use in eletron gun type pick-up tubes comprising a transparent conductive film, a first thin amorphous solid layer provided on said conductive film, a second thin amorphous solid layer, and a porous layer intervening between said first and second thin amorphous solid layers, all of said layers consisting essentially of a photoconductive material of the V-Vl group of compounds, at least one of said solid layers having a multi-layer structure consisting of a plurality of sub-layers, the V- group element content of said photo-conductive material being greater for sub-layers successively remote from said transparent conductive film.
  • a compound photo-conductive target having a structure consisting of a transparent conductive film, an amorphous porous layer deposited in an inert gas atmosphere under low vacuum, and an amorphous solid layer deposited under highvacuum and an amorphous intermediate layer deposited in a degree of vacuum intermediate said low vacuum and said high vacuum, all said layers containing a photo-conductive material of the V-VI group of compounds, at least one of said solid layer and said intermediate layer having a multi-layer structure consisting of a plurality of sub-layers, the V- group element content of said photo-conductive material being greater for sub-layers successively remote from said transparent conductive film.

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  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Formation Of Various Coating Films On Cathode Ray Tubes And Lamps (AREA)
  • Photoreceptors In Electrophotography (AREA)
  • Image-Pickup Tubes, Image-Amplification Tubes, And Storage Tubes (AREA)
  • Light Receiving Elements (AREA)
US266708A 1972-06-27 1972-06-27 Photo-conductive target comprising both solid and porous layers Expired - Lifetime US3890524A (en)

Priority Applications (4)

Application Number Priority Date Filing Date Title
US266708A US3890524A (en) 1972-06-27 1972-06-27 Photo-conductive target comprising both solid and porous layers
GB3029572A GB1391953A (en) 1972-06-27 1972-06-28 Compound photo-conductive structure and method of manufacturing the same
FR7223607A FR2191255B1 (el) 1972-06-27 1972-06-29
DE2232171A DE2232171C3 (de) 1972-06-27 1972-06-30 Fotoleitende Verbundsschicht und Verfahren zu deren Herstellung

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
US266708A US3890524A (en) 1972-06-27 1972-06-27 Photo-conductive target comprising both solid and porous layers
GB3029572A GB1391953A (en) 1972-06-27 1972-06-28 Compound photo-conductive structure and method of manufacturing the same
FR7223607A FR2191255B1 (el) 1972-06-27 1972-06-29
DE2232171A DE2232171C3 (de) 1972-06-27 1972-06-30 Fotoleitende Verbundsschicht und Verfahren zu deren Herstellung

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DE (1) DE2232171C3 (el)
FR (1) FR2191255B1 (el)
GB (1) GB1391953A (el)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4007395A (en) * 1974-06-21 1977-02-08 Hitachi, Ltd. Target structure for use in photoconductive image pickup tubes
US4039887A (en) * 1975-06-04 1977-08-02 Rca Corporation Electron emitter including porous antimony
US4249106A (en) * 1978-11-08 1981-02-03 Hitachi, Ltd. Radiation sensitive screen
EP0039219A1 (en) * 1980-04-25 1981-11-04 Hitachi, Ltd. Light sensitive screen and devices including the same
US20040178426A1 (en) * 2001-06-19 2004-09-16 Leonid Melekhov Laminated semiconductor radiation detector

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2910602A (en) * 1956-07-24 1959-10-27 Emi Ltd Light sensitive devices
US2967254A (en) * 1955-02-18 1961-01-03 Rca Corp Composite photoconductive layer
US3350595A (en) * 1965-11-15 1967-10-31 Rca Corp Low dark current photoconductive device
US3361919A (en) * 1964-12-15 1968-01-02 Tokyo Shibaura Electric Co Target including at least three photoconductive layers of lead oxide of similar conductivity type
US3657596A (en) * 1965-05-20 1972-04-18 Westinghouse Electric Corp Electron image device having target comprising porous region adjacent conductive layer and outer, denser region

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1098076A (en) * 1963-09-21 1968-01-03 Electrical & Musical Ind Ltd Improvements relating to photo-conductive coatings

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2967254A (en) * 1955-02-18 1961-01-03 Rca Corp Composite photoconductive layer
US2910602A (en) * 1956-07-24 1959-10-27 Emi Ltd Light sensitive devices
US3361919A (en) * 1964-12-15 1968-01-02 Tokyo Shibaura Electric Co Target including at least three photoconductive layers of lead oxide of similar conductivity type
US3657596A (en) * 1965-05-20 1972-04-18 Westinghouse Electric Corp Electron image device having target comprising porous region adjacent conductive layer and outer, denser region
US3350595A (en) * 1965-11-15 1967-10-31 Rca Corp Low dark current photoconductive device

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4007395A (en) * 1974-06-21 1977-02-08 Hitachi, Ltd. Target structure for use in photoconductive image pickup tubes
US4039887A (en) * 1975-06-04 1977-08-02 Rca Corporation Electron emitter including porous antimony
US4249106A (en) * 1978-11-08 1981-02-03 Hitachi, Ltd. Radiation sensitive screen
EP0039219A1 (en) * 1980-04-25 1981-11-04 Hitachi, Ltd. Light sensitive screen and devices including the same
US4419604A (en) * 1980-04-25 1983-12-06 Hitachi, Ltd. Light sensitive screen
US20040178426A1 (en) * 2001-06-19 2004-09-16 Leonid Melekhov Laminated semiconductor radiation detector

Also Published As

Publication number Publication date
DE2232171A1 (de) 1974-01-17
FR2191255A1 (el) 1974-02-01
DE2232171C3 (de) 1980-07-03
DE2232171B2 (de) 1974-07-18
GB1391953A (en) 1975-04-23
FR2191255B1 (el) 1976-01-16

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