US2905843A - Electron discharge devices employing photo-conductive target electrodes - Google Patents

Electron discharge devices employing photo-conductive target electrodes Download PDF

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Publication number
US2905843A
US2905843A US563801A US56380156A US2905843A US 2905843 A US2905843 A US 2905843A US 563801 A US563801 A US 563801A US 56380156 A US56380156 A US 56380156A US 2905843 A US2905843 A US 2905843A
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United States
Prior art keywords
photo
layer
target
electrode
conductive
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Expired - Lifetime
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US563801A
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English (en)
Inventor
Lubszynski Hans Gerhard
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EMI Ltd
Electrical and Musical Industries Ltd
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EMI 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
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof

Definitions

  • the present invention relates to photo-sensitive devices employing a layer of photo-conductive material and to an improved method of forming such layers.
  • a very important factor of photo-conductive devices such as television pick-up tubes is the photo-conductive lag of the photo-conductive layer and such lag depends to a large extent on the constitution and the thickness of this layer.
  • an electrode formed of a metal which is chosen for its mechanical and electrical properties such as one of the alloys known under the trade names of Eureka or Constantan said alloys comprising approximately 60 percent copper and approximately 40 percent nickel.
  • These alloys will re-act with photo-conductive materials such as antimony trisulphide so that when employed in such devices it is difficult to estimate the amount of photo-conductive material which will be required to repeatedly produce tubes having layers of the same constitution and thickness.
  • a photosensitive device having a target comprising a continuous layer of photo-conductive material, a tubular electrode composed of a metal which reacts with the photo-conductive material of said layer mounted adjacent to said layer, and a coating of a material which is substantially inert to said photo-conductive material provided on at least a portion of the inner wall of said electrode.
  • FIG. 1 shows in Figure 1 the invention applied to the formation of a photo-conductive layer for a television pick-up tube
  • Figure 2 being a portion of the target of the tube of Figure 1 on a much larger scale.
  • the particular pick-up tube shown is one which is suitable for operation with a low velocity scanning beam to restore the scanned surface of the photo-conductive layer to a potential at or near that of the cathode of the tube.
  • the tube shown in the drawing is one having a photo-sensitive layer formed as a double layer of photo-conductive material, the first layer being of a porous or spongy nature and the second layer being of a solid nature.
  • the method of forming devices having such layers is more fully described in the specification of co-pending application Serial No. 563,800 and for this reason only a brief mention of it will be made in the present application.
  • a planar glass window 1 closes one end of a glass envelope 2 and is provided with a target electrode comprising a translucent electrically conducting signal electrode 3 having a first layer 4 of a photo-conducting material deposited in porous form and thereover a second layer 5 of a photoconductive material deposited in solid form.
  • a target electrode comprising a translucent electrically conducting signal electrode 3 having a first layer 4 of a photo-conducting material deposited in porous form and thereover a second layer 5 of a photoconductive material deposited in solid form.
  • an electron gun with its thermionic cathode 6 facing the target and between the gun and target a tubular electrode 7 serving in operation of the tube as an anode having its end adjacent to the target covered with a mesh 8 preferably formed of silver and which in operation of the tube serves as an ion trap.
  • the device shown in Figure 1 is of the Vidicon type and as it usual with such a device the envelope 1 when the device is set up for operation will be surrounded with a suitable coil for electro-magnetically focussing the electron beam from the gun into a well defined beam and further coils for scanning said beam over the surface of the layer 5 of the target. Alignment coils may also be provided in known manner for suitably directing the electron beam towards the target.
  • tubular anode 7 The materials available for the construction of the tubular anode 7 so as to provide a strong mechanical structure having a sufliciently high resistivity so that it will not unduly screen the penetration of the scanning fields for the electron beam are limited and the most suitable materials known for this purpose are alloys comprising approximately 60 percent copper with approximately 40 percent nickel such as those known as Constantan and Eureka wherein the metal employed is of 0.002 inch thickness, although other alloys such as stainless steel or Nichrome are used.
  • the above-mentioned gun and electrodes 7, 8 are assembled in the envelope 2 and a tantalum boat 9 containing a charge of photo-conductive material 10 such as antimony trisulphide is introduced through a side tube 11 so that it is at the centre of the envelope 2 and facing the mesh 8 and target area.
  • the envelope 2 is filled with a gas such as xenon through pump stem 12 at a pressure of approximately 0.4 mm. Hg and with the end of the side tube 11 remote from the envelope 1 closed the boat 9 is heated so that the whole of the charge is evaporated.
  • the antimony trisulphide is thus deposited through the mesh 8 to form the spongy base layer 4 over the target area.
  • the thickness of the spongy layer 4 is determined by the amount of the original charge of material 10 in the evaporator boat 9, the shadow ratio of the mesh 8 and the gas pressure and this can be reasonably calculated in order to obtain a desired low capacitance for such layer.
  • the thickness and construction of the solid layer 5 will thus depend on the amount of material which is deposited on the bars of the mesh 8 and the inner surface of the electrode 7, but despite carefully controlled processing it is found that the thickness of this second solid layer 5 will vary from tube to tube with consequent variations in the sensitivity of the tubes.
  • the photo-conductive material '10 is antimony trisulphide
  • sufficient protection is afforded by coating, such as by plating, the internal surface of the electrode 7 with rhodium.
  • Other metals such as gold, platinum, oriridium which are known to be substantially inertto photo-'conductir e materials such as antimony trisulp'hide or selenium are also satisfactory for this purpose.
  • the dimensions for an electrode 7 which is typical for a tube of the above construction is 0.8 inch diameter and three inchesinlength and it is found that adequate protectionzis alfordedif the inner wall of this cylinder is plated with one of the above protecting metals over a length of 2 /2 inches from the end thereof .to which is secured the mesh 8.
  • the invention has beendescribed as applied to the construction of pick-up tubes suitable for operationwithlow velocity scanning, it is applicable to pick-up tubes with .high .velocity scanning and generally to devices having a photo-sensitive layer of-photo-conductivematerial in which an electrode is provided which requires to be protected against the action of thephotoconductive material employed in theconstructionof the device.
  • a light sensitivedevice having a target comprising a continuous layer of photo-conductive material, a tubular electrode composed of a metal which reacts with the photo-conductive material of said layer mounted adjacent to said layer, and a coating of a material which is substantially inert .to said photo-conductive material provided on at least a portion of the inner wall ofsaid electrode.
  • a light sensitive device having a target comprising a continuous layer of a photoconductive material, a tubularelectrode composed of a metal which reacts with the photo-conductive material of said target mounted .adjacentto saidtargetand acoating on at least a portion of the inner Wall of said electrode of a metal selected from the group rhodium, gold, platinum or iridium.
  • a light sensitive deyj ce having a target comprising a porous layer of a photo'conductive material and coverin sai i c ca laye eeen nu usselid layer o nhot conduetivermateri l, .-..a:tu.b111 r electrode composed of a metal whichreacts with the photo conductive material o s d tar steamed adjac n said t r an faci said layer, and ac'oating of a-rnaterial which is substantially inert to the photo conductive material of said target-providedon atrleasta portiontof the inner wall of said electrode.
  • a lightsensiti-vegdeyice having -a target comprising a continuous layer of a' photo-conductive material, a tubular electrode composd ofan alloy of copper and nickel mounted adjacent to said layer and a coating of a material which is substantially inert to said photo conductive-material on at: least aportion of the innerwall of said electrode.
  • a light sensitive device having a-target comprising a layer ofiantimony-tri sulphide, a tubular electrode composcdota metal which reacts with antimonytri-sulphide mounted adjacentsaid-target and acoatingof a material which is inert to antimony tri-sulphide on at least a portion of the :inner wall of said electrode.
  • a light sensitive device having within its envelope a target comprising a porous layerof a photo-conductive material and covering said porous layer a continuous solid :layer of a photo conductive material, a tubular electrode .composed of a metal which reacts with the photoconductive material of said target, said electrode being mounted in said envelope adjacent said target and supporting aimetal mesh extendingtransversely of said tubularteleetrodeatthe end thereof which is nearer said target, and a coatingof amaterialwhich is substantially inert-to ,the-photosconductive material of said target on at least a .portionof the inner wall of said electrode.

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  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Physics & Mathematics (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • General Physics & Mathematics (AREA)
  • Computer Hardware Design (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Power Engineering (AREA)
  • Formation Of Various Coating Films On Cathode Ray Tubes And Lamps (AREA)
  • Photoreceptors In Electrophotography (AREA)
US563801A 1955-02-15 1956-02-06 Electron discharge devices employing photo-conductive target electrodes Expired - Lifetime US2905843A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB4407/55A GB827059A (en) 1955-02-15 1955-02-15 Improvements in or relating to photo-sensitive devices employing photo-conductive layers

Publications (1)

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US2905843A true US2905843A (en) 1959-09-22

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US563801A Expired - Lifetime US2905843A (en) 1955-02-15 1956-02-06 Electron discharge devices employing photo-conductive target electrodes

Country Status (5)

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US (1) US2905843A (enrdf_load_stackoverflow)
DE (1) DE1046794B (enrdf_load_stackoverflow)
FR (1) FR1141316A (enrdf_load_stackoverflow)
GB (1) GB827059A (enrdf_load_stackoverflow)
NL (1) NL204284A (enrdf_load_stackoverflow)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3048502A (en) * 1959-05-22 1962-08-07 Westinghouse Electric Corp Method of making a photoconductive target
US3061664A (en) * 1959-11-13 1962-10-30 Kimble Glass Co Glass-to-metal seals and method of fabricating same
US3327152A (en) * 1964-12-23 1967-06-20 Alfred L Greilich Non-photoemissive grid for a phototube and process for making same
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
US3786945A (en) * 1973-01-15 1974-01-22 Deere & Co Spout control system

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
NL112456C (enrdf_load_stackoverflow) * 1958-01-06
US2951962A (en) * 1959-05-22 1960-09-06 Rca Corp Pickup tube assembly

Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2077442A (en) * 1932-08-25 1937-04-20 Emi Ltd Cathode ray tube
US2156769A (en) * 1935-02-28 1939-05-02 Rca Corp Cathode ray device
US2413606A (en) * 1944-09-01 1946-12-31 Libbey Owens Ford Glass Co Method of coating by evaporating metals
US2452619A (en) * 1946-02-07 1948-11-02 Rca Corp Cathode-ray tube
US2458205A (en) * 1946-09-27 1949-01-04 Rca Corp Televison pickup tube
US2600121A (en) * 1945-10-06 1952-06-10 Electric & Musieal Ind Ltd Deposition of material onto a mosaic screen through a stencil
US2656287A (en) * 1949-06-29 1953-10-20 Westinghouse Electric Corp Process for the precision evaporation of antimony
US2663814A (en) * 1950-10-30 1953-12-22 Hartford Nat Bank & Trust Co Electron-optical image intensifier
US2687484A (en) * 1951-02-24 1954-08-24 Rca Corp Photoconductive target
US2745032A (en) * 1951-06-01 1956-05-08 Rca Corp Photo-conductive targets for cathode ray devices

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE879581C (de) * 1937-06-12 1953-06-15 Aeg Photoelement mit Traegerelektrode aus Aluminium
DE737089C (de) * 1939-05-06 1943-07-05 Sueddeutsche App Fabrik G M B Verfahren zur Herstellung von Sperrschicht-Photozellen
DE887250C (de) * 1943-05-28 1953-08-20 Aeg Verfahren zur Herstellung von Photowiderstaenden
NL70500C (enrdf_load_stackoverflow) * 1943-12-15 1900-01-01 Westinghouse Electric Corp
DE838693C (de) * 1949-05-07 1952-05-12 Immanuel Broser Dr Ing Verfahren zur Regelung des Lumineszenz- und Leitvermoegens an Einkristall- und Grobkristallschichten
DE892945C (de) * 1951-11-21 1953-10-12 Sueddeutsche App Fabrik G M B Verfahren zur Herstellung von Selenphotoelementen

Patent Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2077442A (en) * 1932-08-25 1937-04-20 Emi Ltd Cathode ray tube
US2156769A (en) * 1935-02-28 1939-05-02 Rca Corp Cathode ray device
US2413606A (en) * 1944-09-01 1946-12-31 Libbey Owens Ford Glass Co Method of coating by evaporating metals
US2600121A (en) * 1945-10-06 1952-06-10 Electric & Musieal Ind Ltd Deposition of material onto a mosaic screen through a stencil
US2452619A (en) * 1946-02-07 1948-11-02 Rca Corp Cathode-ray tube
US2458205A (en) * 1946-09-27 1949-01-04 Rca Corp Televison pickup tube
US2656287A (en) * 1949-06-29 1953-10-20 Westinghouse Electric Corp Process for the precision evaporation of antimony
US2663814A (en) * 1950-10-30 1953-12-22 Hartford Nat Bank & Trust Co Electron-optical image intensifier
US2687484A (en) * 1951-02-24 1954-08-24 Rca Corp Photoconductive target
US2745032A (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
US3048502A (en) * 1959-05-22 1962-08-07 Westinghouse Electric Corp Method of making a photoconductive target
US3061664A (en) * 1959-11-13 1962-10-30 Kimble Glass Co Glass-to-metal seals and method of fabricating same
US3327152A (en) * 1964-12-23 1967-06-20 Alfred L Greilich Non-photoemissive grid for a phototube and process for making same
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
US3786945A (en) * 1973-01-15 1974-01-22 Deere & Co Spout control system

Also Published As

Publication number Publication date
NL204284A (enrdf_load_stackoverflow)
DE1046794B (de) 1958-12-18
GB827059A (en) 1960-02-03
FR1141316A (fr) 1957-08-30

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