US2128582A - Photoelectric surface - Google Patents

Photoelectric surface Download PDF

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Publication number
US2128582A
US2128582A US96613A US9661336A US2128582A US 2128582 A US2128582 A US 2128582A US 96613 A US96613 A US 96613A US 9661336 A US9661336 A US 9661336A US 2128582 A US2128582 A US 2128582A
Authority
US
United States
Prior art keywords
caesium
silver
tube
photoelectric
oxygen
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
US96613A
Other languages
English (en)
Inventor
Bernard C Gardner
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.)
Farnsworth Television Inc
Original Assignee
Farnsworth Television Inc
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 NL51128D priority Critical patent/NL51128C/xx
Application filed by Farnsworth Television Inc filed Critical Farnsworth Television Inc
Priority to US96613A priority patent/US2128582A/en
Application granted granted Critical
Publication of US2128582A publication Critical patent/US2128582A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • 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
    • H01J9/02—Manufacture of electrodes or electrode systems
    • H01J9/12—Manufacture of electrodes or electrode systems of photo-emissive cathodes; of secondary-emission electrodes
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J40/00—Photoelectric discharge tubes not involving the ionisation of a gas
    • H01J40/02—Details
    • H01J40/04—Electrodes
    • H01J40/06—Photo-emissive cathodes

Definitions

  • My invention relates to photoelectric tubes and, more particularly, to a means-and method for obtaining a photoelectric surface of high sensitivity
  • Figure' 1 is a diagram showing a tube'and apparatus setup by which the photosurface .of my invention may be formed.
  • Figure 2 is a cross-sectional view of the tube shown in Figure 1.
  • My method allows the use of excess quantities 'of alkali metal, the sensitization being accomplished' by oxidization of the final deposit.
  • I do not remove the excess alkali metal from the tube, but simply change it from a metal to an oxide, the latter being non-conductive, ⁇ thus leakage is eliminated.
  • An envelope i is provided with a cathode foundation member 2 and an anode 3.
  • the tube is sealed onto an exhaust line 4 to whichoxygen may be supplied through a stopcock or other suitable vmeans 5.
  • Caesium metal is placed in a still tube t by which the metal may be Vessel. ,f 'f
  • the caesium metal is then distilled in through the still tube 6 in excess quantity, and no attempt need be made to put in any denite quantity, though I usually prefer to admit about twice the amount which would normally be needed.
  • the silver turns a bright golden color due to the deposition on the oxide layer of a relatively large amount of metallic caesium.
  • the etching step described above prevents such iiow and consequent irregularities.
  • the etching insures that the caesium will be deposited uniformly upon the silver oxide.
  • the cathode is sensitive only to the point that metallic caesium would give a photoelectric, response and in addition, the walls of the tube have enough metallic caesium thereon to cause sufficient leakage to prevent proper operation of the device.
  • I then readmit oxygen'. and the caesiumsurface changes color and appears almost black. Oxygen again is admitted until all conductivity along the Walls of the device is killed. If no convenient connection can be made within the tube to determine Whether or not conductivity across a link is destroyed, then I may prefer to insert a pair of spaced contacts l and d and join them by a circuit concerning a battery 9 and an indieating device ill. necessary in specific cases where contacts for determining leakage cannot readily be obtained with the normal electrode structure.
  • the thermionic emission point has been reached, and I have foundthat the peak of the .photoelectric current is reached when the thermionic current lis between zero andl one hundred microamperes from a surface area of apprommately nine' square inches at 200 centigrade.
  • the method of forming photoelectrlc surfaces in an envelope comprising depositing a silver surface therein, oxidizing said silver surface admitting an excess of alkali metal, admitting oxygen until all metal other than that directly assoelated withl said silver oxide is changed to alkali metal oxide, and continuing the admission of oxygen until thermionic emission appears from said surface at 200 centigrade.
  • a photoelectric surface comprising in order a silver layer, a' silver oxide layer, a caesium metal layer, and a caesium oxide layer.
  • a method of preparing a silver surface to receive a deposit of photoelectric material which comprises the step of etching said surface in at hydrogen flame.

Landscapes

  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Image-Pickup Tubes, Image-Amplification Tubes, And Storage Tubes (AREA)
US96613A 1936-08-18 1936-08-18 Photoelectric surface Expired - Lifetime US2128582A (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
NL51128D NL51128C (en:Method) 1936-08-18
US96613A US2128582A (en) 1936-08-18 1936-08-18 Photoelectric surface

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US499891XA 1936-08-18 1936-08-18
US96613A US2128582A (en) 1936-08-18 1936-08-18 Photoelectric surface

Publications (1)

Publication Number Publication Date
US2128582A true US2128582A (en) 1938-08-30

Family

ID=26727781

Family Applications (1)

Application Number Title Priority Date Filing Date
US96613A Expired - Lifetime US2128582A (en) 1936-08-18 1936-08-18 Photoelectric surface

Country Status (2)

Country Link
US (1) US2128582A (en:Method)
NL (1) NL51128C (en:Method)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2440917A (en) * 1946-03-08 1948-05-04 Farnsworth Res Corp Phototube cathode formation
US2507359A (en) * 1943-01-27 1950-05-09 Herbert Friedman Automatic fire alarm
US5314363A (en) * 1993-06-08 1994-05-24 Itt Corporation Automated system and method for assembling image intensifier tubes

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2507359A (en) * 1943-01-27 1950-05-09 Herbert Friedman Automatic fire alarm
US2440917A (en) * 1946-03-08 1948-05-04 Farnsworth Res Corp Phototube cathode formation
US5314363A (en) * 1993-06-08 1994-05-24 Itt Corporation Automated system and method for assembling image intensifier tubes

Also Published As

Publication number Publication date
NL51128C (en:Method)

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