US3350594A - Image intensifier having continuous conducting layer between porous metallic coating and luminescent layer - Google Patents
Image intensifier having continuous conducting layer between porous metallic coating and luminescent layer Download PDFInfo
- Publication number
- US3350594A US3350594A US385664A US38566464A US3350594A US 3350594 A US3350594 A US 3350594A US 385664 A US385664 A US 385664A US 38566464 A US38566464 A US 38566464A US 3350594 A US3350594 A US 3350594A
- Authority
- US
- United States
- Prior art keywords
- photo
- target
- layer
- electrons
- image
- 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
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Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J43/00—Secondary-emission tubes; Electron-multiplier tubes
- H01J43/04—Electron multipliers
- H01J43/06—Electrode arrangements
- H01J43/08—Cathode arrangements
-
- 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
-
- 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
-
- 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
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J2231/00—Cathode ray tubes or electron beam tubes
- H01J2231/50—Imaging and conversion tubes
- H01J2231/50057—Imaging and conversion tubes characterised by form of output stage
- H01J2231/50063—Optical
Definitions
- This invention relates to photo-electron emissive discharge devices in which image intensification can be achieved by accelera-ting the photo-electrons and causing them to impinge on a target with a high velocity.
- the invention is applicable for example to image intensiliers, photo-multiplier devices or'television or other image pick-up devices.
- the object of the present invention is to provide an improved photo-electron emissive discharge device in which image intensification can be achieved 'by accelerating the photo-electrons and causing them to impinge on a target with a high velocity, with a view to reducing the liability for spurious signals to -be produced.
- an image intensifier positive ions released from the surface of the luminescent screen in which the intensified light image is produced may impinge on the photocathode with energies of l0 kilovolts or more and each ion may produce several secondary electrons.
- a photo-electron emissive discharge device comprising a photo-electron emissive cathode for converting incident light into an electron stream, a target for said elect-ron stream, said target being arranged to receive a high voltage so that electrons of said electron stream can impinge on the target with a high velocity and wherein to reduce the release of ions the surface of the ltarget on which the photo-electrons impinge is provided with a porous coating ⁇ formed by evaporation of metal onto the surface of the target in a gaseous atmosphere, which coating tends to trap such ions.
- the porous coating is effective because the ions remain trapped for a sufficient time to enable their cha-rge to be neutrolised.
- the porous coating is a metal coating formed by evaporating a suitable metal in a gaseous atmosphere.
- Any other electrode at which when the device is operating the electric field intensity is suicient for release of ions may also be provided with a porous coating.
- an accelerating elect-rode or more than one accelerating electrode disposed between the photo-cathode and the target may be provided with a porous coating.
- a further spurious noise signal may be set up in a photo-electron emissive discharge device by reflected light feedback.
- the photo-emissive cathode of the device is semi-transparent, as in the case of an antimony photo-cathode sensitised with caesium or with a plurality of alkali metals, some incident light, particularly at the long wave end of the visual spectrum may pass through said photo-cathode and subsequently be refiected back to said photo-cathode by other electrodes in the device or by glass or aluminised surfaces for example.
- the above mentioned porous coating is of such a material as to provide an intense, black, non-reflecting surface so as to reduce said light reflection.
- FIGURE 1 shows one -form of photo-electron emissive discharge devices according -to an embodiment of the invention
- FIGURE 2 is a detail of FIGURE 1 on an enlarged scale.
- a single stage image intensifier which comprises a substantially cylindrical envelope 1 having on one end wall a photo-electron emissive cathode 2 which may by way of example be of antimony sensitised with caesium or a plurality of alkali metals.
- a luminescent screen 3' On the other end Wall of the envelope 1 there is formed a luminescent screen 3'.
- an annular accelerating electrode 4 and during operation of the device, the envelope 1 4will be surrounded by a focussing coil and the electrode 4 and screen 3 wlill be maintained at high positive potentials with respect to the photo-cathode 2.
- the luminescent screen 3 is shown in greater detail in FIGURE 2 and comprises a layer 5 of luminescent material which may be formed ⁇ on the end wall of envelope 1 by gravity deposition or electrophoresis.
- the layer 5 is covered with a layer 6 of aluminum which is evaporated in a high vacuum, for example Iat a pressure of 2 105 millimetres of mercury, the layer 6 having a thickness between 250 A. and 1,000 A.
- the layer 6 is then covered by a porous coating 7 which may also be of aluminium evaporated in an atmosphere of an inert gas such as argon at a pressure between 0.2 and 2 millimetres of mercury.
- a coating 7 of suitable thickness may be formed by evaporating 10 milligrams of aluminium at a distance of 31/2 inches from the surface on which it is to be deposited, the area of the surface being about 20 sq. cms.
- the porous coating 7 of aluminium provides a black non-refiecting surface, and a similar coating may, if desired be provided on the electrode 4.
- a similar coating may, if desired be provided on the electrode 4.
- the porous coating 7 should not substantially reduce the energy of penetrating electrons and for this purpose a low density material such as aluminium for the porous coating is particularly desirable.
- other materials may be used to form the porous coating. Examples of such materials are gold and silver.
- the device which is illustrated in FIGURES 1 and 2 When the device which is illustrated in FIGURES 1 and 2 is in operation it is connected to an external circuit in such a way that the accelerating electrode 4 is maintained at va positive potential of 5 kilovolts with respect to the photo-cathode 2 whilst the aluminium layer 6 on the luminescent screen 5 is maintained at a positive potential of kilovolts, also with respect to the photo-cathode 2.
- the intensifier is moreover disposed inside a focussing solenoid which produces the magnetic eld parallel to the axis of the intensier.
- the invention is also applicable to image intensifiers having a plurality of stages, each with a photocathode, in which case one or more of the luminescent screens may include a porous layer.
- the invention can also be applied to other photo-electron emissive devices such as image orthicons or other television or image pick-up tubes or photo-multiplier devices.
- One type of television or image pick-up tube to which the invention is especially applicable is a tube of the type in which the target comprises a layer of insulating material which exhibits electron bombardment induced conductivity.
- the photo-electrons from the photo-cathode impinge on the target with a very high velocity, in the order of l0 kilo electron volts.
- the image electrons are therefore particularly liable to liberate positive ions from the surface of the target on which they impinge.
- the conductivity induced by the image electrons causes charges to be accumulated on different elemental areas of the target. These charges are discharged periodically by scanning the target with a low velocity electron beam, for example. If electron beam scanning is employed, the scanning section of the tube is generally of a similar construction to the scanning section of an image orthicon.
- a photo-electron emissive discharge device comprising a photo-electron emissive cathode for converting incident light into an electron stream, a target for said electron stream, said target being arranged to receive a high voltage so that electrons of said electron stream can impinge on the target with a high velocity and wherein to reduce the release of ions the surface of the target on which the photo-electrons impinge is provided with a porous coating formed by evaporation of metal onto the surface of the target in a gaseous atmosphere, which coating tends to trap such ions, said device constituting an image intensier and in which said cathode converts an incident light image into an electron image which in operation of the device impinges on said target, land said target comprises a luminescent layer having a conducting metallic layer formed on the surface of the luminescent layer facing said cathode by evaporation in a high vacuum, said porous layer being provided on said conducting layer.
Landscapes
- Image-Pickup Tubes, Image-Amplification Tubes, And Storage Tubes (AREA)
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB3067863A GB1090774A (en) | 1963-08-02 | 1963-08-02 | Improvements in or relating to photo-electron emissive discharge devices |
GB30678/64A GB1025505A (en) | 1963-07-22 | 1964-07-24 | Coating process |
Publications (1)
Publication Number | Publication Date |
---|---|
US3350594A true US3350594A (en) | 1967-10-31 |
Family
ID=26260549
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US385664A Expired - Lifetime US3350594A (en) | 1963-08-02 | 1964-07-28 | Image intensifier having continuous conducting layer between porous metallic coating and luminescent layer |
Country Status (3)
Country | Link |
---|---|
US (1) | US3350594A (xx) |
DE (1) | DE1289587B (xx) |
NL (1) | NL6408758A (xx) |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3449582A (en) * | 1966-02-02 | 1969-06-10 | Westinghouse Electric Corp | Electron multiplier device having an electrically insulating secondary emission control surface |
US3774038A (en) * | 1971-04-16 | 1973-11-20 | Philips Corp | Imaging device comprising an image-intensifying tube |
US3973157A (en) * | 1974-01-07 | 1976-08-03 | S.A.E.S. Getters S.P.A. | Charged-particle trapping electrode |
US4251748A (en) * | 1976-04-12 | 1981-02-17 | U.S. Philips Corporation | Camera tube having photocathode absorptive of shorter wavelength and filter absorptive of longer wavelength light |
Families Citing this family (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
NL7611593A (nl) * | 1976-10-20 | 1978-04-24 | Optische Ind De Oude Delft Nv | Werkwijze voor het in een beeldversterkerbuis aanbrengen van een lichtabsorberende, voor elek- tronen doorlaatbare laag. |
DE3315011A1 (de) * | 1983-04-26 | 1984-10-31 | Licentia Patent-Verwaltungs-Gmbh, 6000 Frankfurt | Elektronenroehre mit leuchtschirm |
Citations (11)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2155465A (en) * | 1937-01-12 | 1939-04-25 | Firm Fernseh Ag | Fluorescent screen for cathode ray tubes |
US2303563A (en) * | 1941-05-09 | 1942-12-01 | Rca Corp | Cathode ray tube and luminescent screen |
US2544754A (en) * | 1947-12-04 | 1951-03-13 | Bell Telephone Labor Inc | Electron camera tube |
GB651728A (en) * | 1939-02-14 | 1951-04-11 | Alfred De Quervain | Improvements in or relating to cathode-ray tubes |
GB668854A (en) * | 1948-05-08 | 1952-03-26 | Westinghouse Electric Int Co | Improvements in or relating to image intensifiers |
US2616057A (en) * | 1950-05-20 | 1952-10-28 | Westinghouse Electric Corp | Black screen television cathode-ray tube |
US2898499A (en) * | 1956-05-23 | 1959-08-04 | Westinghouse Electric Corp | Transmission secondary emission dynode structure |
US2942130A (en) * | 1957-02-25 | 1960-06-21 | Corning Glass Works | Aperture mask coating to prevent cathode poisoning |
US2960416A (en) * | 1952-07-29 | 1960-11-15 | Rauland Corp | Method of manufacturing screens for electron-discharge devices |
US2994798A (en) * | 1946-12-26 | 1961-08-01 | Gardner L Krieger | High voltage image tube |
US3073989A (en) * | 1960-04-18 | 1963-01-15 | Michael F Amsterdam | Image converter device |
Family Cites Families (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE733611C (de) * | 1937-11-10 | 1943-03-30 | Ig Farbenindustrie Ag | Vorrichtung zur Sichtbarmachung von Korpuskularstrahlen |
NL92230C (xx) * | 1951-08-25 | |||
NL164276B (nl) * | 1951-09-27 | Sandoz Ag | Werkwijze voor het bereiden van een 1,3-difenyl- pyrazoline, van een preparaat voor het optisch bleken van vezelmaterialen door een of een aantal van deze pyrazolinen op te lossen in water en werkwijze voor het optisch bleken van vezelmaterialen met deze 1,3- -difenylpyrazolinen, alsmede onder toepassing van laatstgenoemde werkwijze verkregen optisch gebleekte vezelmaterialen. | |
DE1055711B (de) * | 1957-08-05 | 1959-04-23 | Siemens Ag Albis | Bildwandlerroehre |
DE1125090B (de) * | 1960-05-21 | 1962-03-08 | Telefunken Patent | Bildwandlerroehre mit Leuchtschirm |
-
1964
- 1964-07-28 US US385664A patent/US3350594A/en not_active Expired - Lifetime
- 1964-07-30 NL NL6408758A patent/NL6408758A/xx unknown
- 1964-07-31 DE DEE27519A patent/DE1289587B/de active Pending
Patent Citations (11)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2155465A (en) * | 1937-01-12 | 1939-04-25 | Firm Fernseh Ag | Fluorescent screen for cathode ray tubes |
GB651728A (en) * | 1939-02-14 | 1951-04-11 | Alfred De Quervain | Improvements in or relating to cathode-ray tubes |
US2303563A (en) * | 1941-05-09 | 1942-12-01 | Rca Corp | Cathode ray tube and luminescent screen |
US2994798A (en) * | 1946-12-26 | 1961-08-01 | Gardner L Krieger | High voltage image tube |
US2544754A (en) * | 1947-12-04 | 1951-03-13 | Bell Telephone Labor Inc | Electron camera tube |
GB668854A (en) * | 1948-05-08 | 1952-03-26 | Westinghouse Electric Int Co | Improvements in or relating to image intensifiers |
US2616057A (en) * | 1950-05-20 | 1952-10-28 | Westinghouse Electric Corp | Black screen television cathode-ray tube |
US2960416A (en) * | 1952-07-29 | 1960-11-15 | Rauland Corp | Method of manufacturing screens for electron-discharge devices |
US2898499A (en) * | 1956-05-23 | 1959-08-04 | Westinghouse Electric Corp | Transmission secondary emission dynode structure |
US2942130A (en) * | 1957-02-25 | 1960-06-21 | Corning Glass Works | Aperture mask coating to prevent cathode poisoning |
US3073989A (en) * | 1960-04-18 | 1963-01-15 | Michael F Amsterdam | Image converter device |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3449582A (en) * | 1966-02-02 | 1969-06-10 | Westinghouse Electric Corp | Electron multiplier device having an electrically insulating secondary emission control surface |
US3774038A (en) * | 1971-04-16 | 1973-11-20 | Philips Corp | Imaging device comprising an image-intensifying tube |
US3973157A (en) * | 1974-01-07 | 1976-08-03 | S.A.E.S. Getters S.P.A. | Charged-particle trapping electrode |
US4251748A (en) * | 1976-04-12 | 1981-02-17 | U.S. Philips Corporation | Camera tube having photocathode absorptive of shorter wavelength and filter absorptive of longer wavelength light |
Also Published As
Publication number | Publication date |
---|---|
NL6408758A (xx) | 1965-02-03 |
DE1289587B (de) | 1969-02-20 |
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