US2198479A - Image reproduction - Google Patents

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Publication number
US2198479A
US2198479A US172509A US17250937A US2198479A US 2198479 A US2198479 A US 2198479A US 172509 A US172509 A US 172509A US 17250937 A US17250937 A US 17250937A US 2198479 A US2198479 A US 2198479A
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image
radiations
image reproduction
primary
rays
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Expired - Lifetime
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US172509A
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Langmuir Irving
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General Electric Co
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General Electric Co
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    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01JELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J29/00Details of cathode-ray tubes or of electron-beam tubes of the types covered by group H01J31/00
    • H01J29/02Electrodes; Screens; Mounting, supporting, spacing or insulating thereof
    • H01J29/10Screens on or from which an image or pattern is formed, picked up, converted or stored
    • H01J29/36Photoelectric screens; Charge-storage screens
    • H01J29/38Photoelectric screens; Charge-storage screens not using charge storage, e.g. photo-emissive screen, extended cathode
    • H01J29/385Photocathodes comprising a layer which modified the wave length of impinging radiation

Definitions

  • the present invention relates to image reproduction, and more particularly to improvements in image reproduction systems of the type described and claimed in Patent No. 2,158,853 of4 5 W. D. Coolidge, granted May 16, 1939, and assigned to the General Electric Company.
  • Coolidge patent discloses apparatus by means of which a relatively Weak or transitory primary visible image produced by a source of radiation, for example X-rays (including gamma-rays) or other ultra-visible radiations may be converted into a secondary visible image of substantially greater intensity or greater This is ac.
  • a source of radiation for example X-rays (including gamma-rays) or other ultra-visible radiations
  • Fig. 1 there is shown at the extreme left of the figure an X-ray tube comprising a cathode I0 and a target or anode II. poses radiations originating at the target II impinge upon an object to be examined, such an object being represented in the present case as a human hand I3; Radiations transmitted .through the object are caused to fall upon the end wall I5 of an evacuated transparent or translucent envelope I6, suitably of glass which constitutes the enclosure for an image reproduction device.
  • the wall I5 is provided with common means whereby the transmitted X-radiations may be successively converted into a visible image and then into a beam of photoelectrons having a section pattern cor- In the use of this device for diagnostic pur- (Cl.
  • Such a means may include, for example, a combination of fluorescent and photoelectrlc materials applied to the inside of the wall I5.
  • One particular combination which I consider suitable for this purpose comprises a layer of calcium tungstate supercially coated with a film of photoelectrically active material.
  • the photoelectrlc lm is preferably at least slightly conductive in character and should be so thin as to ⁇ be substantially transparent. It may be composed, for example, of a deposit of slightly oxidized silver which has been activated with an alkali metal, preferably caesium.
  • the physical structure of the composite surface is indicated in Fig.
  • I1 is a layer of a material which is adapted to iiuoresce under the influence of X-rays and I8 is a conducting transparent film comprising a photoelectric substance.
  • the uorescent and photoelectrlc materials may be admixed to form a single layer. Under the action of impinging X-radiations /the fluorescent material will form a visible image whose nature will be determined by that ofthe interposed object I3. The light thereby devel.- oped will in turn be effective to release electrons from vthe associated photoactive material in a pattern which corresponds closely to that of the image itself.
  • the electrons so developed may be focused electron-optically to impinge on another fluorescent screen 20 where they will produce a secondary visible image corresponding in outline to the section pattern of the electron beam. If, during the transition'period the electrons are accelerated to a sufficiently high velocity, this secondary image may be of substantially greater intensity than the primary image. Consequently, a camera positioned as indicated at 30 may obtain a good photographic record of the image even though a relatively weak source of X-rays is employed.
  • a suitable accelerating and focusing system is shown as comprising an accelerating electrode 2I adapted to be charged to a high potential with respect to the emissive lsurface I8 and an associated focusing electrode mating at the cathode surface I8 may be caused to form on the fluorescent screen 20 a clear and intensified secondary image corresponding to the primary image which appears on the surface I1.
  • a composite electrode comprising a layer of calcium tungstate adapted to be excited to iiuorescence by the action of impinging radiations and a transparent film of oxidized silver thereon, said lm being photoelectrically activated with caesium, whereby fluorescence of the calcium tungstate layer results in electron emission from the electrode.
  • a source of primary radiations an electrode exposed to the said primary radiations and having contiguously arranged uorescent and photoelectric components, the iiuorescent component being adapted to luminesce in response to impingement of the said primary radiations thereon, and the photoelectric coinponent being substantially non-emissive when excited solely by said primary radiations but being capable of effective electron emission when excited by light from the iiuorescent component, and image-reproducing means for receiving electrons emitted by the photoelectric component in response to excitation of the flucrescent component by the said primary radiations.
  • a source of X-rays deiining a primary image an electrode exposed to the saidsource and having a photovelectric component arranged in direct contact with a fluorescent component which is adapted to luminesce when excited by X-rays, the said photoelectric component being substantially nonemissive when excited solely by X-rays but being

Description

pril 23, 1940. 1 LANGMUlR 2,198,479
IMAGE REPRODUCTION Filed Nov. 3, 1937 FLUORESCENT Inventor Irving) Lam muir,
Hiq Attorney.
Patented Apr. 23, 1940 UNITED STATES PATENT OFFICE to General Electric of New York Company, a corporation Application November s, 1937, serial No. 172,509
3 Claims.
The present invention relates to image reproduction, and more particularly to improvements in image reproduction systems of the type described and claimed in Patent No. 2,158,853 of4 5 W. D. Coolidge, granted May 16, 1939, and assigned to the General Electric Company.
The aforementioned Coolidge patent discloses apparatus by means of which a relatively Weak or transitory primary visible image produced by a source of radiation, for example X-rays (including gamma-rays) or other ultra-visible radiations may be converted into a secondary visible image of substantially greater intensity or greater This is ac.
face which comprises fluorescent and photoelectric materials in close mechanical association.
The features of novelty which I desire to protect herein will be pointed out with particularity in the appended claims. The-invention itself, together with further objects and advantages thereof, will best be understood by reference to the following specification taken in connection with the drawing, in which Fig.A 1 shows in partial section an image reproduction system suitably embodying the invention and Figs. 2 and 3 show fragmentary details of various parts of the construction of Fig. 1.
Referring particularly to Fig. 1 there is shown at the extreme left of the figure an X-ray tube comprising a cathode I0 and a target or anode II. poses radiations originating at the target II impinge upon an object to be examined, such an object being represented in the present case as a human hand I3; Radiations transmitted .through the object are caused to fall upon the end wall I5 of an evacuated transparent or translucent envelope I6, suitably of glass which constitutes the enclosure for an image reproduction device. In accordance with the invention the wall I5 is provided with common means whereby the transmitted X-radiations may be successively converted into a visible image and then into a beam of photoelectrons having a section pattern cor- In the use of this device for diagnostic pur- (Cl. Z-153) responding to that of the visible image. Such a means may include, for example, a combination of fluorescent and photoelectrlc materials applied to the inside of the wall I5. One particular combination which I consider suitable for this purpose comprises a layer of calcium tungstate supercially coated with a film of photoelectrically active material. The photoelectrlc lm is preferably at least slightly conductive in character and should be so thin as to `be substantially transparent. It may be composed, for example, of a deposit of slightly oxidized silver which has been activated with an alkali metal, preferably caesium. The physical structure of the composite surface is indicated in Fig. 2 in which I1 is a layer of a material which is adapted to iiuoresce under the influence of X-rays and I8 is a conducting transparent film comprising a photoelectric substance. In an alternative arrangement the uorescent and photoelectrlc materials may be admixed to form a single layer. Under the action of impinging X-radiations /the fluorescent material will form a visible image whose nature will be determined by that ofthe interposed object I3. The light thereby devel.- oped will in turn be effective to release electrons from vthe associated photoactive material in a pattern which corresponds closely to that of the image itself. As explained in the Coolidge application above referredto, the electrons so developed may be focused electron-optically to impinge on another fluorescent screen 20 where they will produce a secondary visible image corresponding in outline to the section pattern of the electron beam. If, during the transition'period the electrons are accelerated to a sufficiently high velocity, this secondary image may be of substantially greater intensity than the primary image. Consequently, a camera positioned as indicated at 30 may obtain a good photographic record of the image even though a relatively weak source of X-rays is employed.
In the present instance a suitable accelerating and focusing system is shown as comprising an accelerating electrode 2I adapted to be charged to a high potential with respect to the emissive lsurface I8 and an associated focusing electrode mating at the cathode surface I8 may be caused to form on the fluorescent screen 20 a clear and intensified secondary image corresponding to the primary image which appears on the surface I1. In some cases it may be desirable to augment the electron-optical lens formed by the electrodes 2| and 23 by means of additional magnetic or electrostatic focusing means.
While I have shown particular embodiments of my invention, it will be understood by those skilled in the art that many modifications may be made without departing from the invention, and I aim by the appended claims to cover all such modifications as fall within the true spirit and scope of my invention.
What I claim as new and desire to obtain by Letters Patent of the United States is:
1. A composite electrode comprising a layer of calcium tungstate adapted to be excited to iiuorescence by the action of impinging radiations and a transparent film of oxidized silver thereon, said lm being photoelectrically activated with caesium, whereby fluorescence of the calcium tungstate layer results in electron emission from the electrode.
2. In an image-reproducing system, a source of primary radiations, an electrode exposed to the said primary radiations and having contiguously arranged uorescent and photoelectric components, the iiuorescent component being adapted to luminesce in response to impingement of the said primary radiations thereon, and the photoelectric coinponent being substantially non-emissive when excited solely by said primary radiations but being capable of effective electron emission when excited by light from the iiuorescent component, and image-reproducing means for receiving electrons emitted by the photoelectric component in response to excitation of the flucrescent component by the said primary radiations.
3. In an image-reproducing system, a source of X-rays deiining a primary image, an electrode exposed to the saidsource and having a photovelectric component arranged in direct contact with a fluorescent component which is adapted to luminesce when excited by X-rays, the said photoelectric component being substantially nonemissive when excited solely by X-rays but being
US172509A 1937-11-03 1937-11-03 Image reproduction Expired - Lifetime US2198479A (en)

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Cited By (33)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2523132A (en) * 1949-08-10 1950-09-19 Westinghouse Electric Corp Photosensitive apparatus
US2527913A (en) * 1947-08-06 1950-10-31 Radio Industrie Sa Photoelectric device
US2530517A (en) * 1944-11-01 1950-11-21 X Ray Electronic Corp X-ray testing and measuring method and apparatus
US2555424A (en) * 1948-03-09 1951-06-05 Sheldon Edward Emanuel Apparatus for fluoroscopy and radiography
US2555423A (en) * 1947-04-16 1951-06-05 Sheldon Edward Emanuel Image intensifying tube
US2586392A (en) * 1948-12-09 1952-02-19 Sheldon Edward Emanuel Motion-picture camera for X-ray images
US2586391A (en) * 1947-07-08 1952-02-19 Sheldon Edward Emanuel Device for projection of microwave images
US2593925A (en) * 1948-10-05 1952-04-22 Sheldon Edward Emanuel Device for color projection of invisible rays
US2603757A (en) * 1948-11-05 1952-07-15 Sheldon Edward Emanuel Photocathode
US2612610A (en) * 1948-11-06 1952-09-30 Westinghouse Electric Corp Radiation detector
US2660686A (en) * 1948-06-19 1953-11-24 Westinghouse Electric Corp Fluorescent screen
US2660539A (en) * 1948-06-19 1953-11-24 Westinghouse Electric Corp Method for producing a fluorescent screen
US2666864A (en) * 1950-01-20 1954-01-19 Westinghouse Electric Corp Image intensifier tube
US2681868A (en) * 1949-08-10 1954-06-22 Westinghouse Electric Corp Image amplifier
US2690516A (en) * 1948-03-09 1954-09-28 Shcldon Edward Emanuel Method and device for producing neutron images
US2692300A (en) * 1950-07-06 1954-10-19 Alsede W Hogan Electric image formation and control apparatus
US2692299A (en) * 1948-12-11 1954-10-19 Westinghouse Electric Corp Image contrast intensifier
US2727183A (en) * 1948-12-22 1955-12-13 Westinghouse Electric Corp Radiation detector of the scanning type
US2739257A (en) * 1948-10-15 1956-03-20 Sheldon Edward Emanuel Device for x-ray motion pictures
US2739258A (en) * 1950-05-19 1956-03-20 Edward E Sheldon System of intensification of x-ray images
US2782332A (en) * 1949-04-06 1957-02-19 Sheldon Edward Emanuel Method and device for reading images of invisible radiation
US2804561A (en) * 1948-03-09 1957-08-27 Sheldon Edward Emanuel X-ray camera
DE968667C (en) * 1952-04-04 1958-04-17 Philips Nv Imager
US2864031A (en) * 1950-12-30 1958-12-09 Rca Corp Electrical storage tube
US2955219A (en) * 1959-02-16 1960-10-04 Rauland Corp Electron discharge device
US3014147A (en) * 1947-04-09 1961-12-19 Rca Corp Infra red image tube
US3400291A (en) * 1964-08-28 1968-09-03 Sheldon Edward Emanuel Image intensifying tubes provided with an array of electron multiplying members
US3443104A (en) * 1966-02-17 1969-05-06 Rauland Corp Image intensifier tube with shading compensation
US3461332A (en) * 1965-11-26 1969-08-12 Edward E Sheldon Vacuum tubes with a curved electron image intensifying device
US3922523A (en) * 1973-05-16 1975-11-25 Sheldon Edward E Apparatus for producing x-ray images as radiographs
US4186302A (en) * 1976-11-12 1980-01-29 Diagnostic Information, Inc. Panel type X-ray image intensifier tube and radiographic camera system
US4300046A (en) * 1978-07-12 1981-11-10 Diagnostic Information, Inc. Panel type X-ray image intensifier tube and radiographic camera system
US20030169847A1 (en) * 2001-11-21 2003-09-11 University Of Massachusetts Medical Center System and method for x-ray fluoroscopic imaging

Cited By (34)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2530517A (en) * 1944-11-01 1950-11-21 X Ray Electronic Corp X-ray testing and measuring method and apparatus
US3014147A (en) * 1947-04-09 1961-12-19 Rca Corp Infra red image tube
US2555423A (en) * 1947-04-16 1951-06-05 Sheldon Edward Emanuel Image intensifying tube
US2586391A (en) * 1947-07-08 1952-02-19 Sheldon Edward Emanuel Device for projection of microwave images
US2527913A (en) * 1947-08-06 1950-10-31 Radio Industrie Sa Photoelectric device
US2555424A (en) * 1948-03-09 1951-06-05 Sheldon Edward Emanuel Apparatus for fluoroscopy and radiography
US2804561A (en) * 1948-03-09 1957-08-27 Sheldon Edward Emanuel X-ray camera
US2690516A (en) * 1948-03-09 1954-09-28 Shcldon Edward Emanuel Method and device for producing neutron images
US2660686A (en) * 1948-06-19 1953-11-24 Westinghouse Electric Corp Fluorescent screen
US2660539A (en) * 1948-06-19 1953-11-24 Westinghouse Electric Corp Method for producing a fluorescent screen
US2593925A (en) * 1948-10-05 1952-04-22 Sheldon Edward Emanuel Device for color projection of invisible rays
US2739257A (en) * 1948-10-15 1956-03-20 Sheldon Edward Emanuel Device for x-ray motion pictures
US2603757A (en) * 1948-11-05 1952-07-15 Sheldon Edward Emanuel Photocathode
US2612610A (en) * 1948-11-06 1952-09-30 Westinghouse Electric Corp Radiation detector
US2586392A (en) * 1948-12-09 1952-02-19 Sheldon Edward Emanuel Motion-picture camera for X-ray images
US2692299A (en) * 1948-12-11 1954-10-19 Westinghouse Electric Corp Image contrast intensifier
US2727183A (en) * 1948-12-22 1955-12-13 Westinghouse Electric Corp Radiation detector of the scanning type
US2782332A (en) * 1949-04-06 1957-02-19 Sheldon Edward Emanuel Method and device for reading images of invisible radiation
US2681868A (en) * 1949-08-10 1954-06-22 Westinghouse Electric Corp Image amplifier
US2523132A (en) * 1949-08-10 1950-09-19 Westinghouse Electric Corp Photosensitive apparatus
US2666864A (en) * 1950-01-20 1954-01-19 Westinghouse Electric Corp Image intensifier tube
US2739258A (en) * 1950-05-19 1956-03-20 Edward E Sheldon System of intensification of x-ray images
US2692300A (en) * 1950-07-06 1954-10-19 Alsede W Hogan Electric image formation and control apparatus
US2864031A (en) * 1950-12-30 1958-12-09 Rca Corp Electrical storage tube
DE968667C (en) * 1952-04-04 1958-04-17 Philips Nv Imager
US2955219A (en) * 1959-02-16 1960-10-04 Rauland Corp Electron discharge device
US3400291A (en) * 1964-08-28 1968-09-03 Sheldon Edward Emanuel Image intensifying tubes provided with an array of electron multiplying members
US3461332A (en) * 1965-11-26 1969-08-12 Edward E Sheldon Vacuum tubes with a curved electron image intensifying device
US3443104A (en) * 1966-02-17 1969-05-06 Rauland Corp Image intensifier tube with shading compensation
US3922523A (en) * 1973-05-16 1975-11-25 Sheldon Edward E Apparatus for producing x-ray images as radiographs
US4186302A (en) * 1976-11-12 1980-01-29 Diagnostic Information, Inc. Panel type X-ray image intensifier tube and radiographic camera system
US4300046A (en) * 1978-07-12 1981-11-10 Diagnostic Information, Inc. Panel type X-ray image intensifier tube and radiographic camera system
US20030169847A1 (en) * 2001-11-21 2003-09-11 University Of Massachusetts Medical Center System and method for x-ray fluoroscopic imaging
US6895077B2 (en) 2001-11-21 2005-05-17 University Of Massachusetts Medical Center System and method for x-ray fluoroscopic imaging

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