GB712254A - Improvements in or relating to cathode ray tubes and arrangements therefor - Google Patents

Improvements in or relating to cathode ray tubes and arrangements therefor

Info

Publication number
GB712254A
GB712254A GB2235751A GB2235751A GB712254A GB 712254 A GB712254 A GB 712254A GB 2235751 A GB2235751 A GB 2235751A GB 2235751 A GB2235751 A GB 2235751A GB 712254 A GB712254 A GB 712254A
Authority
GB
United Kingdom
Prior art keywords
anode
cathode
electrons
coating
secondary electrons
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
Application number
GB2235751A
Inventor
Hilary Moss
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.)
EMI Ltd
Electrical and Musical Industries Ltd
Original Assignee
EMI Ltd
Electrical and Musical Industries Ltd
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
Application filed by EMI Ltd, Electrical and Musical Industries Ltd filed Critical EMI Ltd
Priority to GB2235751A priority Critical patent/GB712254A/en
Publication of GB712254A publication Critical patent/GB712254A/en
Expired legal-status Critical Current

Links

Classifications

    • 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
    • H01J29/18—Luminescent screens
    • H01J29/28—Luminescent screens with protective, conductive or reflective layers

Landscapes

  • Image-Pickup Tubes, Image-Amplification Tubes, And Storage Tubes (AREA)

Abstract

712,254. Cathode-ray tubes. ELECTRIC & MUSICAL INDUSTRIES, Ltd. Sept. 17, 1952 [Sept 25, 1951], No. 22357/51. Class 39(1) A cathode-ray tube comprising an electron gun including a cathode and one or more accelerating electrodes for generating a primary beam of electrons directed towards a fluorescent screen, is provided with a secondary-electron-emitting electrode arranged in the path of the beam so' that electrons from the beam will impinge on it and generate secondary electrons which travel to the screen with a velocity less than the velocity of the beam so that in operation any liability for negative charging of the screen by the impact of the primary beam is counteracted. In one embodiment, Fig. 1, the anode 4 has a frusto-conical end 9 which may be of nickel coated with barium and magnesium oxides so that it is secondary-emissive; the edges of the beam strike the end 9 and produce secondary electrons. The anode 4 may be connected by a spring contact 12 to a wall coating 10 joined by a resistive coating 11 to a further wall coating 6 connected to the main H.T. supply. Thus the primary beam may be accelerated to 1.5 kV energy but the secondary electrons will have an energy of only about 1000 volts since the anode 4 is about 1000 volts below the potential of the coating 6 due to the resistive coating 11; the negative charge produced on the fluorescent screen by the primary beam may thus be neutralized by the secondary electrons. In another embodiment, Fig. 2, (not shown, the anode 4 is tubular and is provided with a secondary-emissive grid across the end remote from the cathode to generate the secondary electrons. The anode is provided with a separate leadin terminal instead of being connected to a wall coating. As an alternative to these two arrangements a secondary emissive surface may be mounted directly from the final accelerating-electrode of the tube by means of a support or supports of high resistance material.
GB2235751A 1951-09-25 1951-09-25 Improvements in or relating to cathode ray tubes and arrangements therefor Expired GB712254A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB2235751A GB712254A (en) 1951-09-25 1951-09-25 Improvements in or relating to cathode ray tubes and arrangements therefor

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB2235751A GB712254A (en) 1951-09-25 1951-09-25 Improvements in or relating to cathode ray tubes and arrangements therefor

Publications (1)

Publication Number Publication Date
GB712254A true GB712254A (en) 1954-07-21

Family

ID=10178086

Family Applications (1)

Application Number Title Priority Date Filing Date
GB2235751A Expired GB712254A (en) 1951-09-25 1951-09-25 Improvements in or relating to cathode ray tubes and arrangements therefor

Country Status (1)

Country Link
GB (1) GB712254A (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2935635A (en) * 1957-11-18 1960-05-03 Philco Corp Cathode ray tube display system
US3024385A (en) * 1958-05-06 1962-03-06 Sylvania Electric Prod Image display device

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2935635A (en) * 1957-11-18 1960-05-03 Philco Corp Cathode ray tube display system
US3024385A (en) * 1958-05-06 1962-03-06 Sylvania Electric Prod Image display device

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