US3787745A - Electron tube for electron-optical image conversion - Google Patents

Electron tube for electron-optical image conversion Download PDF

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Publication number
US3787745A
US3787745A US00241771A US3787745DA US3787745A US 3787745 A US3787745 A US 3787745A US 00241771 A US00241771 A US 00241771A US 3787745D A US3787745D A US 3787745DA US 3787745 A US3787745 A US 3787745A
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United States
Prior art keywords
photo
jacket portion
cathode
window
electron
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Expired - Lifetime
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US00241771A
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English (en)
Inventor
C Wulms
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US Philips Corp
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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
    • H01J29/96—One or more circuit elements structurally associated with the tube
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J31/00—Cathode ray tubes; Electron beam tubes
    • H01J31/08—Cathode ray tubes; Electron beam tubes having a screen on or from which an image or pattern is formed, picked up, converted, or stored
    • H01J31/50—Image-conversion or image-amplification tubes, i.e. having optical, X-ray, or analogous input, and optical output
    • H01J31/501—Image-conversion or image-amplification tubes, i.e. having optical, X-ray, or analogous input, and optical output with an electrostatic electron optic system

Definitions

  • Electron-optical image converting tube comprising a photoelectric cathode and a focusing electrode applied to the tube wall, the end of the focusing electrode facing the photocathode being separated from the wall by insulating material which increases the insulation resistance between the photocathode and the focusing electrode.
  • the invention relates to an electron tube for electron-optical image conversion comprising a cylindrical glass sheath closed at both ends, the inner surface of which is coated with a conductive layer and' provided at one end with a substantially spherical glass window adapted to support a photo-electric cathode and at the other end a phosphor screen for capturing electrons emitted by the photo-cathode and focused by an electron-optical system arranged between the photocathode and the screen.
  • Electronic image tubes of this kind are known for image transformation, for example, for converting an X-ray image into a visible image and for increasing the brightness of visible images of low light intensity.
  • the conductive coating on the cylindrical sheath covers the wall substantially completely and terminates at a given distance from the photo-cathode.
  • This ring comprises two equal portions of circular section, having at one edge a projecting flange, while the other edge of one portion is connected with the window by being sealed to the cylinder wall and that of the other portion is connected in the same manner.
  • the two flanges may be sealed together by welding.
  • the metal wall coating is usually of copper or aluminum and with tubes of the last-mentioned type it covers the sealing edge between the cylindrical sheath and the metal ring, to which it is connected electrically.
  • the size of the photo-cathode surface imaged without defects is about 65 percent of the tube section.
  • a comparatively large image converter is required relative to the size of the image to be transferred.
  • the invention has for its objects to provide an improvement in electron-optical image tubes in order to enlarge further the useful photo-cathode surface.
  • This improvement is obtained in that in accordance with the invention with the metal coating on the wall of the cylinder sheath of the tube the end extending towards the cathode is at a distance from the cylindrical sheath and is prolonged along a surface separated from the sealing area between the cylindrical sheath and the glass window by insulating material.
  • an annular glass body may be provided inside the sheath and be secured to the wall by means of a kind of glass of lower melting point, for example, glass enamel.
  • the invention is based on the recognition of the fact that the comparatively narrow portion of the spherical window along the circumference of the photo-cathode not associated with the latter is slightly contaminated during the formation of the photo-cathode by a small deposit of photo-cathode material, so that its insulation resistance is reduced.
  • the wall coating terminates in the vicinity of the seal or at the metal connecting ring, the applied voltage will produce, due to the reduced resistance surface-conduction currents which result in electrons emerging from the neighbourhood of the edge of the photo-cathode which travel towards the phosphor screen under the action of the modified, usually no longer uniform potential distribution along other paths than those required for accurate focussing.
  • the glass ring increases satisfactorily the insulation capacity between the ,wall coating and the photo-cathode, although the portion of insulation material between them is not materially prolonged.
  • the active cathode surface is increased to or percent of the tube section.
  • the metal connecting ring beat cathode potential
  • the ring may be provided on the sealing side on the sheath with an inwardly projecting rim bent over parallel to the ring surface, so that between this rim and the ring a gutter-shaped space is formed.
  • a different embodiment in which a coating with glass-like insulating material is avoided is the. applica tion of a second metal ring in the cylinder wall, said ring being separated by a wall portion from the connecting ring, the former ring having connected with it a metal screen extending towards the photo-cathode beyond said intermediate wall portion insulating the two rings from each other, so that the connecting ring may be at photo-cathode potential.
  • FIG. la is a sectional fragmentary view of one embodiment of the electron image tube of the invention.
  • FIG. 1b is a sectional fragmentary view of a modification of the tube of FIG. la;
  • FIGS. 2 and 3 show each another embodiment of this invention.
  • FIG. 1b shows the embodiment in which the cylindrical jacket or sheath and the window 6 are interconnected by a metal ring 7.
  • the tube accommodates the photo-cathode 1, the phosphor screen 2, the anode 3 of the electron-optical system and the focussing electrode 4 formed by the wall coating.
  • the envelope of this space is formed by a cylindrical glass sheath 5 and a glass window 6.
  • the window 6 is directly connected with the cylindrical sheath 5.
  • the cylindrical sheath 5 is closed by an end wall 8 having an embossed part 9 connected at the edge with a contracted part 10.
  • the photo-cathode 1 is arranged on the concave surface of the spherical window 6, in this case a photocathode for direct exposure as is common in a light intensifier.
  • the display of X-ray images in visible light requires a phosphor layer which is provided with the supporting surface and the photo-cathode.
  • the anode 3 is arranged with a cylindrical rim 1 l on the re-entrant part 10 and furthermore provided with a conical part 12 which terminates in a substantially spherical top 13 having an axial opening 14.
  • the part of the inner space enclosed by the anode 3 accommodates the phosphor display screen 2 arranged on the flat upper surface of the re-entrant wall portion 10.
  • the metal ring 7 as illustrated in FlG.. lb is made of two parts with flanges 17 and 18, the connection between the window 6 and the cylindrical sheath 5 can be easily established. Thesetwo parts may each have sealed to them a metal ring portion, after which the flanges are interconnected in an airtight manner, for example, by welding.
  • the inner side of the sheath 6 is provided with an annular body 19 of glass or another refractory insulating material.
  • the body 19 may be fastened by means of a vitreous material 20, for example, glass enamel, to the cylindrical sheath 5 or to the half of the metal ring sealed to the cylindrical sheath 5 in order to join the two tube portions 5 and 6 so that the connecting material covers in addition the sealing rim between the ring and the wall.
  • the metal inner coating 4 of the wall may be obtained in an appropriate manner by vapour deposition of metal particles, the whole surface being covered with the exeption of the annular surface 21 of the body 19 in the sheath facing the photo-cathode 1. With this structure it is possible to keep this surface chemically clean, since the formation of the photo-cathode may be carried out before the two tube portions are sealed to each other. i j
  • FIG. 2 The detail of .a tube with a metal connecting ring of FIG. 2 shows that one half of the ring has a channelshaped'section, one limb 21 being coated with a vitreous insulating material 20, which covers in addition the sealing edge of the ring with the tube wall.
  • the metal coating 4 extends up to the end of said limb 21.
  • the non-conductive coating of this limb in the gutter-shaped space 22 forms an exellent insulation between the metal coating 4 and the ring 7, which may be connected to earth, so that non-uniform voltage distribution in the neighbourhood of the photo-cathode is completely avoided.
  • a portion 24 of the cylindrical sheat 5 is used as an insulation.
  • the metal wall coating 4 terminates at the metal intermediate portion 25 provided by the connection of the sleeve 23 and being annular in shape, the two edges of which are sealed to the cylinder wall.
  • the sleeve 23 is electrically connected to the conductive coating 4 and owing to the presence of the insulating portion 24 of the cylinder wall 5 it is no longer necessary to cover the wall of the sleeve with insulating material.
  • a further advantage of the constructions shown resides in that the metal coating operating as a focussing electrode in the electron-optical system can be extended towards the photo-cathode so as to terminate at a distance most suitable for the focussing effect independently of the disposition of the metal ring connectiiig the window with the cylindrical sheath of the tube.
  • An electron tube for electron optical image conversion comprising a closed envelope of insulating material including a jacket portion having an axis of symmetry, and two opposite end portions, each provided with a transparent window arranged about said axis, a photo-cathode layer disposed adjacent the inner surface of one window,
  • a phosphor screen layer arranged adjacent the opposite window
  • anodestructure mounted within said envelope around said phosphor screen and defining a passage for electrons emitted by said photo-cathode
  • an electrically conductive focusing coating provided on the inner surface of said tacket portion and surrounding at least a portion of said anode structure, amarginal portion of said focusing coating near said photo-cathode layer being spaced from said jacket portion to form an annular channel therewith, and i an insulating layer provided on the jacket portion within said annular channel to eliminate accidental contamination of said jacket portion by photocathode material.
  • said jacket portion is of glass
  • said coating of insulating material including an annular glass body which is fastened to the tube wall by means of a glass material of lower melting point than that of the jacket portion, the focusing coating exceeding the inner surface of the glass body.
  • An electrode tube according to claim 3 further comprising a metal ring sealingly connected between said closure member and the rim of said jacket portion, at least a part of the inner surface of said metal ring forming together with the bent marginal portion of said focusing coating, said annular channel and being provided with said insulating layer.
  • An electron tube for electron optical image conversion comprising a closed envelope of insulating material including a jacket portion having an axis of symmetry, and two opposite end portions each provided with a transparent window arranged about said axis,
  • a photo-cathode layer disposed adjacent the inner surface of one window
  • anode structure mounted within said envelope around said phosphor screen and defining a passage for electrons emitted by said photo-cathode
  • first metal ring sealing connecting said jacket portion to said one end portion having the window with the photo-cathode layer, a second metal ring sealingly interrupting said jacket portion at a distance from said first metal ring,
  • a metal sleeve disposed within and spaced from said jacket portion, said focusing coating and one end of said sleeve being connected to said second ring, said sleeve protecting the section of the jacket portion between the two rings from accidental continuation by the photo-cathode material.

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  • Image-Pickup Tubes, Image-Amplification Tubes, And Storage Tubes (AREA)
US00241771A 1969-03-13 1972-04-06 Electron tube for electron-optical image conversion Expired - Lifetime US3787745A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
NL6903860A NL6903860A (enrdf_load_stackoverflow) 1969-03-13 1969-03-13

Publications (1)

Publication Number Publication Date
US3787745A true US3787745A (en) 1974-01-22

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Application Number Title Priority Date Filing Date
US00241771A Expired - Lifetime US3787745A (en) 1969-03-13 1972-04-06 Electron tube for electron-optical image conversion

Country Status (6)

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US (1) US3787745A (enrdf_load_stackoverflow)
CH (1) CH502694A (enrdf_load_stackoverflow)
DE (1) DE2008170A1 (enrdf_load_stackoverflow)
FR (1) FR2037189A1 (enrdf_load_stackoverflow)
GB (1) GB1280952A (enrdf_load_stackoverflow)
NL (1) NL6903860A (enrdf_load_stackoverflow)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4001618A (en) * 1975-01-29 1977-01-04 Rca Corporation Electron discharge image tube with electrostatic field shaping electrode
US4581536A (en) * 1983-03-04 1986-04-08 Detector Electronics Corp. Radiation detection tube having spurious radiation shield
EP0805477A3 (en) * 1996-05-02 1999-08-25 Hamamatsu Photonics K.K. Electron tube
US6297489B1 (en) 1996-05-02 2001-10-02 Hamamatsu Photonics K.K. Electron tube having a photoelectron confining mechanism
WO2017045108A1 (en) * 2015-09-14 2017-03-23 Shenzhen Genorivision Technology Co. Ltd. A phototube and method of making it
US10261019B2 (en) 2015-04-22 2019-04-16 Shenzhen Genorivision Technology Co., Ltd. Biosensor
US10670527B2 (en) 2015-09-14 2020-06-02 Shenzhen Genorivision Technology Co., Ltd. Biosensor

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2727182A (en) * 1950-11-06 1955-12-13 Hartford Nat Bank & Trust Co Image transformer with electronoptical image projection
US2828433A (en) * 1956-04-25 1958-03-25 Gen Dynamics Corp Electron gun construction
US3280356A (en) * 1958-07-17 1966-10-18 Rca Corp Image tube with truncated conical anode and a plurality of coaxial shield electrodes
US3474275A (en) * 1966-09-26 1969-10-21 Rca Corp Image tube having a gating and focusing electrode
US3558893A (en) * 1967-01-30 1971-01-26 Picker Corp X- and gamma-ray sensitive image intensification tube
US3562516A (en) * 1967-09-28 1971-02-09 Thomson Hotchkics Brandt Comp Image pickup tube with screen and field grids
US3688146A (en) * 1967-06-09 1972-08-29 Optische Ind De Oude Delft Nv Image amplifier having external electrostatic shield

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2727182A (en) * 1950-11-06 1955-12-13 Hartford Nat Bank & Trust Co Image transformer with electronoptical image projection
US2828433A (en) * 1956-04-25 1958-03-25 Gen Dynamics Corp Electron gun construction
US3280356A (en) * 1958-07-17 1966-10-18 Rca Corp Image tube with truncated conical anode and a plurality of coaxial shield electrodes
US3474275A (en) * 1966-09-26 1969-10-21 Rca Corp Image tube having a gating and focusing electrode
US3558893A (en) * 1967-01-30 1971-01-26 Picker Corp X- and gamma-ray sensitive image intensification tube
US3688146A (en) * 1967-06-09 1972-08-29 Optische Ind De Oude Delft Nv Image amplifier having external electrostatic shield
US3562516A (en) * 1967-09-28 1971-02-09 Thomson Hotchkics Brandt Comp Image pickup tube with screen and field grids

Cited By (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4001618A (en) * 1975-01-29 1977-01-04 Rca Corporation Electron discharge image tube with electrostatic field shaping electrode
US4581536A (en) * 1983-03-04 1986-04-08 Detector Electronics Corp. Radiation detection tube having spurious radiation shield
EP0805477A3 (en) * 1996-05-02 1999-08-25 Hamamatsu Photonics K.K. Electron tube
US6297489B1 (en) 1996-05-02 2001-10-02 Hamamatsu Photonics K.K. Electron tube having a photoelectron confining mechanism
US10261019B2 (en) 2015-04-22 2019-04-16 Shenzhen Genorivision Technology Co., Ltd. Biosensor
US10170289B2 (en) 2015-09-14 2019-01-01 Shenzhen Genorivision Technology Co., Ltd. Phototube and method of making it
CN108140532A (zh) * 2015-09-14 2018-06-08 深圳源光科技有限公司 光电管和制造方法
WO2017045108A1 (en) * 2015-09-14 2017-03-23 Shenzhen Genorivision Technology Co. Ltd. A phototube and method of making it
EP3350825A4 (en) * 2015-09-14 2019-04-17 Shenzhen Genorivision Technology Co., Ltd. PHOTO TUBE AND METHOD FOR THE PRODUCTION THEREOF
CN108140532B (zh) * 2015-09-14 2019-09-27 深圳源光科技有限公司 光电管和制造方法
US10670527B2 (en) 2015-09-14 2020-06-02 Shenzhen Genorivision Technology Co., Ltd. Biosensor
TWI698904B (zh) * 2015-09-14 2020-07-11 大陸商深圳源光科技有限公司 光電管及夜視設備
US10790128B2 (en) 2015-09-14 2020-09-29 Shenzhen Genorivision Technology Co., Ltd. Phototube and method of making it
TWI742630B (zh) * 2015-09-14 2021-10-11 大陸商深圳源光科技有限公司 製作適合於檢測光子的光電管的方法

Also Published As

Publication number Publication date
DE2008170A1 (de) 1970-10-08
CH502694A (de) 1971-01-31
GB1280952A (en) 1972-07-12
FR2037189A1 (enrdf_load_stackoverflow) 1970-12-31
NL6903860A (enrdf_load_stackoverflow) 1970-09-15

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