US2875359A - Photoconductive device - Google Patents

Photoconductive device Download PDF

Info

Publication number
US2875359A
US2875359A US602187A US60218756A US2875359A US 2875359 A US2875359 A US 2875359A US 602187 A US602187 A US 602187A US 60218756 A US60218756 A US 60218756A US 2875359 A US2875359 A US 2875359A
Authority
US
United States
Prior art keywords
sulphide
antimony
photoconductive
deposit
oxy
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
US602187A
Other languages
English (en)
Inventor
Appleton D Cope
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.)
RCA Corp
Original Assignee
RCA Corp
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
Priority to NL110594D priority Critical patent/NL110594C/xx
Priority to NL219620D priority patent/NL219620A/xx
Priority to BE559877D priority patent/BE559877A/xx
Priority to US602187A priority patent/US2875359A/en
Application filed by RCA Corp filed Critical RCA Corp
Priority to JP1622357A priority patent/JPS332417B1/ja
Priority to GB21940/57A priority patent/GB853953A/en
Priority to DER21592A priority patent/DE1039661B/de
Priority to FR1180328D priority patent/FR1180328A/fr
Application granted granted Critical
Publication of US2875359A publication Critical patent/US2875359A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C14/00—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material
    • C23C14/02—Pretreatment of the material to be coated
    • C23C14/027—Graded interfaces
    • 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

Definitions

  • This invention relates to photoconductive devices.
  • this invention relates to an improved photoconductive element for use in a photoconductive device.
  • a photoconductor is a material which is substantially an insulator when in the dark, but which is highly conductive when exposed to light. This change in conductivity, as a result of exposure to light, is limited to the particular areas of the photoconductor which are exposed to the light. Therefore, photoconductive material is extremely useful as the light sensitive member in photoconductive devices such as phototubes,
  • a photoconductor which has the following properties: a high sensitivity, i. e. a large change in conductivity in response to a given amount of light; a low dark current, i. e. a high resistance when in the dark; and a short photoconductive lag, e. the photoconductor returns to its original high resistance state immediately after the light is removed.
  • Some of the photoconductive materials that are known at this time have a high sensitivity coupled with a long photoconductive lag.
  • Other known materials have a short photoconductive lag coupled with low sensitivity.
  • Still others have a short photoconductive lag coupled with a high dark current.
  • a photoconductive material that includes a combination of antimony tri-sulphide and antimony oxysulphide.
  • the novel photoconductive material may be used as the light sensitive element in a pickup tube, a phototube, an electroluminescent device, or in other known types of tubes wherein photosensitivity is utilized.
  • Fig. 1 is a transverse sectional view of a pickup tube utilizing this invention
  • Fig. 2 is an enlarged fragmentary sectional view of the target shown in Fig. 1;
  • Fig. 3 is an enlarged fragmentary sectional view of an embodiment of a target in accordance with this invention.
  • Fig. 4 is a graph of 'the spectral response of a target in accordance with this invention.
  • a transverse sectionalview of a pickup tube in accordance with this invention is shown a transverse sectionalview of a pickup tube in accordance with this invention.
  • the tube 10 is a version of a tube type that is commercially known as a Vidicon.
  • the particular version shown is that of a tube that has ICC a diameter of approximately half an inch.
  • Thelength of the tube is approximately three inches. It should be understood that this particular version of a Vidicon is shown merely to illustrate an example of applicants invention and that other versons of the Vidicon type pickup tube may be utilized in accordance with this invention.
  • the tube 10 comprises an evacuated envelope 11 having an electron gun 12 sealed within one end of the envelope and closed by a glass face plate 34 at the other end.
  • the gun 12 includes a heater 14 which is substantially enclosed by a cathode 16.
  • the cathode 16 may have any of the known types of electron emissive material thereon such as barium oxide.
  • a control electrode 18 Spaced around the cathode 16, and in coaxial alignment therewith, is a control electrode 18 having an aperture in the center of the closed end thereof.
  • 'Spaced from the accelerating electrode 22 is a final accelerating electrode 24 which takes the form of an elongated cylinder having one end closed by a mesh screen 26.
  • the target 28 Spaced closely adjacent to the mesh screen 26 is a target electrode 28.
  • the target 28, which is shown more clearly in Fig. 2, comprises a photoconductive deposit 30 which is supported on a transparent conductor, or signal plate 32, which in turn is supported upon a transparent support member 34.
  • the transparent support member 34 comprises the end wall of the envelope 11. It should be understood that a separate member could be utilized as the support when desired and be spaced from the end of envelope 11.
  • the transparent support, or face plate 34 is sealed to the envelope 11 by means of a sealing ring 36 which may be of any known metal that readily seals to glass.
  • the opposite en d of envelope 11 comprises a stem 37, including an exhaust tubulation 38.
  • the stem 37 supports a plurality of leadin conductors 40 for energizing the various electrodes within the envelope.
  • the stem 37 is also sealed to the balance of the envelope 11 by means of a sealing ring 42 which may be similar to sealing ring 36.
  • the electron beam from gun 12 is scanned over the surface of the photoconductive deposit with low velocity type of scanning.
  • the electron beam drives the scanned surface of the photoconductive deposit to substantially cathode potential.
  • the photoconductive deposit becomes conductive in the4 elemental areas which are struck by the light. The conductivity of the elemental areas permits the charge that has been established on the scanned surface of the photoconductive deposit to leakoff to the transparent conductive coating or signal plate 32.
  • Fig. 1 The potentials shown in Fig. 1 are designed for the low velocity type of scanning. As is known to ⁇ those skilled in the art high velocity type of scanning may also be utilized.
  • the photoconductive deposit 30 comprises a combination of antimony trisulphide and antimony Oxy-sulphide.
  • the antimony tri-sulphide is deposited upon the transparent conductive coating 32 and during the process Vof deposition, the material deposited is gradually changed to antimony Oxy-sulphide.
  • the photoconductive deposit 30 comprises a deposit do of antimony tri-sulphide, a deposit 4S which is a mixture of antimony tri-sulphide and antimony oxysulphide, and a deposit 50 of antimony Oxy-sulphide.
  • the target shown in Figure 2 may be manufactured, as an example, by placing an envelope I l having, a face plate 34 sealed thereto, and a transparent conductive coating 32 therein, in an evacuation chamber such as a bell jar (not shown). While in the bell jar, the face plate and conductive coating may be heated to a temperature within the range of 125 C. to l50 C.
  • the evaporator assembly is pre-heated at a. temperature of approximately 300 for a time of approximately ten minutes.
  • the evaporator assembly may comprise a conductive ribbon containing two pockets, with one pocket containing approximately nine milligrams of antimony tri-sulphide and another pocket containing approximately seven milligrams of antimony Oxy-sulphide.
  • the evapora.or assembly With the evaporator assembly spaced approximately one inch from the face plate, the evapora.or assembly is heated. The temperature of the evaporator is gradually increased from approximately 400 C. tov approximately 600 C. during a period of time of approximately three minutes. At a temperature of approximately 400 C. the antimony trisulphide starts to evaporate and rapid evaporation thereof occurs at a temperature of approximately 450 C. At a temperature of approximately 520 C. the antimony oxysulphide begins to evaporate and rapid evaporation thereof occurs at approximately 580 C.
  • the mixture deposit 48 of antimony tri-sulphide and antimo-ny Oxy-sulphide is approximately 1% microns thick out of total thickness of 2% microns, with deposits 46 and 50 each beingrof approximately the same thickness when utilizing the method preferably described above.
  • the evaporator assembly is placed approximately two inches from the face plate and is loaded with approximately 20 milligrams of antimony tri-sulphide and 16 milligrams of antimony Oxy-sulphide.
  • FIG. 3 there is shown an embodiment of this invention comprising a target 54 having a transparent conductive coating 56 and a deposit of antimony tri-sulphide 58.
  • a target 54 having a transparent conductive coating 56 and a deposit of antimony tri-sulphide 58.
  • antimony tri-sulphide On the deposit of antimony tri-sulphide is aY deposit of antimony Oxy-sulphide 66.
  • Each of the photoconductive deposits 58 and 60 may be approximately l1/4 microns thick and may be deposited by evaporation.
  • the embodiment shown in Figure 3 may be manuactured as described above except that separate evaporators are used for the antimony tri-sulphide and antimony Oxy-sulphide. ln the alternative, a single evaporator may be used and heated to a temperature to evaporate all of the antimony tri-sulphide beforeA the temperature is increased to evaporate any of the antimony Oxy-sulphide.
  • the photosensitive materials are evapo rated ina good vacuum e. g. lO- mm. of mercury. Due to the fact that both of the targets 2S and 54 are substantially inert in the presence of oxygen, after the targets have been deposited, the targets 28 and 54 may be deposited on the face plate 34, which has previously been sealed to the envelope 1l, and before the electron gun parts 12 and the exhaust stem 33 are sealed into the envelope 11.
  • transparent conductive material is a material which hasl substantially no eect on the photosensitive material.
  • Materials within this category and in accordance with this invention are gold, which may be deposited by evaporation to a thickness of several thousand angstrom units; tin chloride which may be deposited by spraying a solution thereof on a heated face plate resulting in a iilm having a resistivity to the order of lil-3 ohms/sq.; or a thin film Vof indium which may be deposited by evaporation and may be of an appropriate thickness.
  • Each of the targets 2S and 54 that have been described, have sensitivities of the order of 2000 micro-amps per lumen.
  • Each of the targets have short photoconductive lag that is a great deal shorter than that of either of the materials when used alone. As an example, when using this invention, less than 20% residual signal can be measured 1/0 of a second after removing the light.
  • Each of the targets has a low dark current, as an example dark currents less than .05 micro amps for target potentials of the order of 25 volts have been measured. Both of the targets have a gamma of unity at low light levels and in the range of 0.5 to 0.6 at high light levels.
  • a photoconductive material including antimonyY tri-sulphide and antimony Oxy-sulphide.
  • a photoconductive material including antimony trisulphide, a mixture of antimony tri-sulphide and antimony Oxy-sulphide, and antimony Oxy-sulphide.
  • a photoconductive device including antimony trisulphide and antimony Oxy-sulphide.
  • An electrode structure comprising a conductor, antimony tri-sulphide on said conductor, and antimony Oxy-sulphide supported by said antimony tri-sulphide.
  • An electrode structure as in claim 4 including aY mixture of antimony tri-sulphide and antimony oxysulphide between said antimony tri-sulphide and said antimony Oxy-sulphide.
  • a target for a; television pickup tube comprising a transparent conductor, a photosensitive deposit on-said conductor, said photosensitive deposit including only a deposit ofv antimony tri-sulphide and a deposit of antimony l Oxy-sulphide.
  • a target for a television camera tube comprising a 5 5 transparent conductor, a photosensitive element on said References Cited in the le of this patent Conductor comprising a deposit of antimony tri-sulphide, UNITED STATES PATENTS a deposit of a mixture of antimony Oxy-sulphide and antimony tri-su1phide, and a deposit of antimony oxy- 2,654,852 Goodrich OC- 6, 1953 sulphide in the order recited with said antimony tn'- 5 2,687,484 Wemr Allg- 24, 1954 sulphide being on said transparent conductor. 2,744,837 Forgue May 8, 1956

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Metallurgy (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Manufacturing & Machinery (AREA)
  • Organic Chemistry (AREA)
  • Formation Of Various Coating Films On Cathode Ray Tubes And Lamps (AREA)
  • Physical Vapour Deposition (AREA)
  • Surface Treatment Of Glass (AREA)
  • Photoreceptors In Electrophotography (AREA)
  • Image-Pickup Tubes, Image-Amplification Tubes, And Storage Tubes (AREA)
  • Light Receiving Elements (AREA)
US602187A 1956-08-06 1956-08-06 Photoconductive device Expired - Lifetime US2875359A (en)

Priority Applications (8)

Application Number Priority Date Filing Date Title
NL110594D NL110594C (OSRAM) 1956-08-06
NL219620D NL219620A (OSRAM) 1956-08-06
BE559877D BE559877A (OSRAM) 1956-08-06
US602187A US2875359A (en) 1956-08-06 1956-08-06 Photoconductive device
JP1622357A JPS332417B1 (OSRAM) 1956-08-06 1957-07-02
GB21940/57A GB853953A (en) 1956-08-06 1957-07-10 Photoconductive device
DER21592A DE1039661B (de) 1956-08-06 1957-07-30 Photoleitfaehige Einrichtung mit einer Schicht aus Antimontrisulfid
FR1180328D FR1180328A (fr) 1956-08-06 1957-07-30 Dispositif photoconducteur

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US602187A US2875359A (en) 1956-08-06 1956-08-06 Photoconductive device

Publications (1)

Publication Number Publication Date
US2875359A true US2875359A (en) 1959-02-24

Family

ID=24410331

Family Applications (1)

Application Number Title Priority Date Filing Date
US602187A Expired - Lifetime US2875359A (en) 1956-08-06 1956-08-06 Photoconductive device

Country Status (7)

Country Link
US (1) US2875359A (OSRAM)
JP (1) JPS332417B1 (OSRAM)
BE (1) BE559877A (OSRAM)
DE (1) DE1039661B (OSRAM)
FR (1) FR1180328A (OSRAM)
GB (1) GB853953A (OSRAM)
NL (2) NL110594C (OSRAM)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3043976A (en) * 1958-01-18 1962-07-10 Leitz Ernst Gmbh Photocathode for photocells, photoelectric quadrupler and the like
US3310700A (en) * 1964-05-28 1967-03-21 Rca Corp Photoconductive device incorporating stabilizing layers on the face of the selenium layer
US3315108A (en) * 1963-12-17 1967-04-18 Rca Corp High lag, high sensitivity target having solid antimony oxysulphide and porous antimony trisulphide layers
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
US3418508A (en) * 1967-08-23 1968-12-24 Gen Electrodynamics Corp Photoconductive layer separated from reactive opaque pattern by transparent conductive layer

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3121186A (en) * 1961-01-06 1964-02-11 Litton Systems Inc Grain boundary television camera tube
DE1131819B (de) 1961-05-06 1962-06-20 Werk Fernsehelektronik Veb Mehrfachschicht aus fotoleitfaehigem Material sowie Verfahren zu ihrer Herstellung

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2654852A (en) * 1951-06-01 1953-10-06 Rca Corp Photoconductive target for cathode-ray devices
US2687484A (en) * 1951-02-24 1954-08-24 Rca Corp Photoconductive target
US2744837A (en) * 1951-06-01 1956-05-08 Rca Corp Photo-conductive targets for cathode ray devices

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE600196C (de) * 1934-07-17 Zeiss Carl Fa Strahlungsempfindliche elektrische Zelle
DE861450C (de) * 1940-05-17 1953-01-05 Patra Patent Treuhand Photoelektrische Widerstandszelle
DE941560C (de) * 1940-12-05 1956-04-12 Patra Patent Treuhand Verfahren zur Herstellung von Photowiderstaenden

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2687484A (en) * 1951-02-24 1954-08-24 Rca Corp Photoconductive target
US2654852A (en) * 1951-06-01 1953-10-06 Rca Corp Photoconductive target for cathode-ray devices
US2744837A (en) * 1951-06-01 1956-05-08 Rca Corp Photo-conductive targets for cathode ray devices

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3043976A (en) * 1958-01-18 1962-07-10 Leitz Ernst Gmbh Photocathode for photocells, photoelectric quadrupler and the like
US3315108A (en) * 1963-12-17 1967-04-18 Rca Corp High lag, high sensitivity target having solid antimony oxysulphide and porous antimony trisulphide layers
US3310700A (en) * 1964-05-28 1967-03-21 Rca Corp Photoconductive device incorporating stabilizing layers on the face of the selenium layer
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
US3418508A (en) * 1967-08-23 1968-12-24 Gen Electrodynamics Corp Photoconductive layer separated from reactive opaque pattern by transparent conductive layer

Also Published As

Publication number Publication date
FR1180328A (fr) 1959-06-03
NL110594C (OSRAM)
JPS332417B1 (OSRAM) 1958-04-09
GB853953A (en) 1960-11-16
NL219620A (OSRAM)
DE1039661B (de) 1958-09-25
BE559877A (OSRAM)

Similar Documents

Publication Publication Date Title
US3350595A (en) Low dark current photoconductive device
US2654853A (en) Photoelectric apparatus
US3293474A (en) Phosphor dielectric storage target for cathode ray tube
US2177736A (en) Television transmitting apparatus
US2654852A (en) Photoconductive target for cathode-ray devices
US2875359A (en) Photoconductive device
US2416720A (en) Electrooptical device
US2967254A (en) Composite photoconductive layer
US2744837A (en) Photo-conductive targets for cathode ray devices
US2212923A (en) Picture transmitter
US3020442A (en) Photoconductive target
US2745032A (en) Photo-conductive targets for cathode ray devices
US2970219A (en) Use of thin film field emitters in luminographs and image intensifiers
US2752519A (en) Method and apparatus for use in chemical evaporation processes
US3148297A (en) Electron device with storage capabilities
US2175691A (en) Photovoltaic target
US2927234A (en) Photoconductive image intensifier
US2810087A (en) Photoconductive orthicon
US3020432A (en) Photoconductive device
US2289921A (en) Photosensitive electrode
US3268764A (en) Radiation sensitive device
US2843774A (en) Light absorbent surfaces
US3048502A (en) Method of making a photoconductive target
US3204142A (en) Pickup tube having photoconductive target
US2753483A (en) Television transmission tubes