US2991393A - High-transconductance cathode-ray tube - Google Patents

High-transconductance cathode-ray tube Download PDF

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Publication number
US2991393A
US2991393A US823028A US82302859A US2991393A US 2991393 A US2991393 A US 2991393A US 823028 A US823028 A US 823028A US 82302859 A US82302859 A US 82302859A US 2991393 A US2991393 A US 2991393A
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US
United States
Prior art keywords
cathode
anode
ray tube
control
transconductance
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
US823028A
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English (en)
Inventor
Francken Jan Carel
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US Philips Corp
North American Philips Co Inc
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US Philips Corp
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Publication date
Application filed by US Philips Corp filed Critical US Philips Corp
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    • 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
    • H01J29/46—Arrangements of electrodes and associated parts for generating or controlling the ray or beam, e.g. electron-optical arrangement
    • H01J29/52—Arrangements for controlling intensity of ray or beam, e.g. for modulation
    • 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
    • H01J29/46—Arrangements of electrodes and associated parts for generating or controlling the ray or beam, e.g. electron-optical arrangement
    • H01J29/48—Electron guns

Definitions

  • the slope of the modulation of the gun of acathode-ray tube may be increased if thecontrol voltages are applied not. only to the control electrode, but also to the accelerating anode.
  • the increase of the penetration factor of the accelerating anode is subject to limitations, since the penetration factor may be incerased by decreasing the thickness of the control electrode and by decreasing the distance between the control electrode and the accelerating anode and cathode with respect to the aperture of the control electrode.
  • the decrease in the distances between thel electrodes is limited by mechanical difficulties, while an increase of the aperture of the grid produces a larger image spot on the screen and hence results in a lower definition of the image.
  • control voltages applied also control one or more auxiliary currents of electrons which strike parts of the accelerating anode, the secondary-emission factor of which is higher than unity and the secondary electrons of which are collected by a positive auxiliary electrode.
  • the control voltages are then transmitted in amplified form to the accelerating anode so that an important increase in the modulation slope of the gun is obtained without the penetration factor requiring an unduly high value.
  • FIG. 1 shows diagrammatically a cathode-ray tube
  • FIG. 2 shows an electron gun according to the invention.
  • T e. gm 4 comprises a cathode with an electron-emitting area '6 a control electrode 7,. a generally cup-like accel-. crating anode 8 and a ring like auxiliary electrode 9. Since the control electrode 7, in addition to the aperture from which an electron ray 10 emergens, has one or more, in this case, two furuther apertures, auxiliary electron currents 11 also strike parts 12 of accelerating anode 8, Theparts 12 are coated .with a material having. a second-.
  • n 5 may e tained' y ub equ y v p r t a silver nd m gesiu aye n the p r 2; su ye s ar l kn n from their use in image orthicons. Since the auxiliary e ectr de 9 has. a.
  • resistor 14 may have a comparatively high value (30 kc) and hence also the amplification of the control voltage applied to ac celerating anode 8 may be high.
  • the electrodes may alternatively be differently shaped within the scope of the invention. Thus, it is possible to take steps for preventing electronemissive material evaporated from the cathode from depositing on the secondary emitting parts of the accelerating anode.
  • a cathode-ray tube exhibiting increased transconductance comprising a cathode source of electrons, an apertured control grid, an apertured accelerating anode having a surface portion exhibiting a secondary emission factor exceeding unity and accessible to primary electrons from the cathode, an auxiliary electrode for collecting the secondary electrons generated at the anode when bombarded by primary electrons from the cathode, an impedance directly connected to the accelerating anode, and means for applying a positive potential to the impedance and thus to the anode, and to the auxiliary electrode.
  • a cathode-ray tube exhibiting increased transconductance comprising a cathode source of electrons, a control grid having a central aperture and a further aperture spaced therefrom, an accelerating anode having a central aperture aligned with the central aperture of the control grid and a surface portion exhibiting a secondary emission factor exceeding unity and aligned with the further aperture in the control grid and thus accessible to primary electrons from the cathode, an auxiliary electrode for collecting the secondary electrons generated at the anode when bombarded by primary electrons from ode, means for applying a positive potential to the auxiliary electrode, means for applying a fluctuating control voltage between the cathode and control grid controlling the flow of electrons through the apertures inthe control grid and accelerating anode and controlling the flow of electrons to the said anode surface portion, and means 1 for applying through an impedance to the anode a positive potential below that applied to the auxiliary electrode, whereby the anode potential fluctuates in accordance with the control voltage fluctuations so as to the

Landscapes

  • Manufacture Of Electron Tubes, Discharge Lamp Vessels, Lead-In Wires, And The Like (AREA)
  • Electrodes For Cathode-Ray Tubes (AREA)
  • Discharge Lamp (AREA)
US823028A 1958-07-17 1959-06-26 High-transconductance cathode-ray tube Expired - Lifetime US2991393A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
NL229698 1958-07-17

Publications (1)

Publication Number Publication Date
US2991393A true US2991393A (en) 1961-07-04

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ID=19751286

Family Applications (1)

Application Number Title Priority Date Filing Date
US823028A Expired - Lifetime US2991393A (en) 1958-07-17 1959-06-26 High-transconductance cathode-ray tube

Country Status (7)

Country Link
US (1) US2991393A (enrdf_load_stackoverflow)
CH (1) CH375082A (enrdf_load_stackoverflow)
DE (1) DE1144408B (enrdf_load_stackoverflow)
ES (1) ES250797A1 (enrdf_load_stackoverflow)
FR (1) FR1230239A (enrdf_load_stackoverflow)
GB (1) GB922537A (enrdf_load_stackoverflow)
NL (1) NL98369C (enrdf_load_stackoverflow)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3243181A (en) * 1963-12-23 1966-03-29 Pitney Bowes Inc Sheet handling device

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1993457A (en) * 1932-05-14 1935-03-05 Schlesinger Kurt Cathode arrangement for braun tubes
US2163210A (en) * 1935-10-14 1939-06-20 Loewe Opta Gmbh Braun tube
US2173498A (en) * 1935-11-16 1939-09-19 Loewe Opta Gmbh Hot cathode arrangement for a cathode ray tube
FR52296E (fr) * 1942-09-15 1943-12-01 Aeg Tube de braun utilisant un multiplicateur électronique comme source d'émission
US2341764A (en) * 1940-03-09 1944-02-15 Gier Johannes De Cathode ray tube system
FR1089337A (fr) * 1952-12-12 1955-03-16 Siemens Ag Tube électronique avec écran lumineux
US2919380A (en) * 1957-07-23 1959-12-29 Philco Corp Electron discharge devices

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1993457A (en) * 1932-05-14 1935-03-05 Schlesinger Kurt Cathode arrangement for braun tubes
US2163210A (en) * 1935-10-14 1939-06-20 Loewe Opta Gmbh Braun tube
US2173498A (en) * 1935-11-16 1939-09-19 Loewe Opta Gmbh Hot cathode arrangement for a cathode ray tube
US2341764A (en) * 1940-03-09 1944-02-15 Gier Johannes De Cathode ray tube system
FR52296E (fr) * 1942-09-15 1943-12-01 Aeg Tube de braun utilisant un multiplicateur électronique comme source d'émission
FR1089337A (fr) * 1952-12-12 1955-03-16 Siemens Ag Tube électronique avec écran lumineux
US2919380A (en) * 1957-07-23 1959-12-29 Philco Corp Electron discharge devices

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3243181A (en) * 1963-12-23 1966-03-29 Pitney Bowes Inc Sheet handling device

Also Published As

Publication number Publication date
ES250797A1 (es) 1960-04-16
CH375082A (de) 1964-02-15
GB922537A (en) 1963-04-03
NL98369C (enrdf_load_stackoverflow)
FR1230239A (fr) 1960-09-14
DE1144408B (de) 1963-02-28

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