US3617791A - Image intensifier including polyimide support - Google Patents

Image intensifier including polyimide support Download PDF

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Publication number
US3617791A
US3617791A US812543A US3617791DA US3617791A US 3617791 A US3617791 A US 3617791A US 812543 A US812543 A US 812543A US 3617791D A US3617791D A US 3617791DA US 3617791 A US3617791 A US 3617791A
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US
United States
Prior art keywords
support
layer
polyimide
fluorescent
image intensifier
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
US812543A
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English (en)
Inventor
Karl Franz
Gerhard Kochmann
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.)
Siemens AG
Siemens Corp
Original Assignee
Siemens Corp
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
Priority claimed from DE19681622999 external-priority patent/DE1622999C3/de
Application filed by Siemens Corp filed Critical Siemens Corp
Application granted granted Critical
Publication of US3617791A publication Critical patent/US3617791A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • G—PHYSICS
    • G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
    • G21K—TECHNIQUES FOR HANDLING PARTICLES OR IONISING RADIATION NOT OTHERWISE PROVIDED FOR; IRRADIATION DEVICES; GAMMA RAY OR X-RAY MICROSCOPES
    • G21K4/00—Conversion screens for the conversion of the spatial distribution of X-rays or particle radiation into visible images, e.g. fluoroscopic 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
    • H01J29/24—Supports for luminescent material
    • 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
    • H01J29/36—Photoelectric screens; Charge-storage screens
    • H01J29/38—Photoelectric screens; Charge-storage screens not using charge storage, e.g. photo-emissive screen, extended cathode
    • H01J29/385—Photocathodes comprising a layer which modified the wave length of impinging radiation
    • 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

  • a screen which comprises a support on which is arranged a layer of a substance capable of fluorescing has the support formed of a polyimide.
  • the screen is suitable for use in a vacuum image intensifier.
  • This invention relates to a screen capable of fluorescing, e.g., a screen capable of making visible invisible images, in which the screen comprises a layer of fluorescent substance arranged on a support.
  • Fluorescent screens of this type are used in vacuum image intensifiers, in which a photocathode is situated in an evacuated flask or bulb behind a ray-entry surface, which may be employed for the conversion of invisible ray images, for example X-ray images, into electron images. Behind the cathode are electron-optically active electrodes and a fluorescent screen on which visible images are formed by the electrons emitted by the photocathode and focused by the voltages applied to the electrodes.
  • Known fluorescent screens by which are meant screens which fluoresce when they absorb radiation, which are used in, for example, image intensifiers, usually have glass, mica or aluminum oxide foils which act as a support on which the fluorescing layer is applied.
  • mica suffers from the disadvantage that it gives off water of crystallization, for example when being used under high vacuum at elevated temperatures and when being bombarded with electrons, and thus it can cause a decrease in transmission as well as a deterioration of the vacuum.
  • the mica does, in fact, become cloudy because of the water of crystallization being given off.
  • mica has only a small degree of hardness and is thus a material which can easily be damaged, together with the fluorescent coating. in addition, because of its laminated structure, flaking can easily occur, especially at the edges.
  • foils consisting of glass are used as the transparent supports in most cases.
  • these foils suffer from the disadvantage that they produce a reduction in contrast when they have the necessary thickness to give sufficient strength for handling purposes. This is because the luminescent light of the fluorescent layer is reflected at the boundary surfaces of the support in such a manner that the light is spread out disturbingly in the support parallel to the image surface.
  • the resultant brightening of the background causes a deterioration in the clear image formation, because of the reduction in the contrast on account of the brightening effect. Since this impairment of the image formation depends mainly on the thickness of the support, efforts have been made to use glass foils which are as thin as possible.
  • the reduction in layer thickness is limited, because of the necessary mechanical strength and the methods by which these foils may be produced, to about 100p.
  • a screen which comprises a support on which is disposed a layer of substance capable of fluorescing, characterized in that the support is formed of a polyimide.
  • Foils formed of polyimide have proved very satisfactory under high vacuum as supports for fluorescent layers, because they are stable up to temperatures of 350 C. under vacuum, are not adversely affected by the loading caused by ionizing radiation, e.g., when used in X-ray image intensifiers, and are resistant to those chemicals which are generally employed in coating with fluorescent substance. Furthermore, polyimide foils still have sufficient strength, even when their thickness is below 15 1.. Accordingly, they provide the possibility of improving the contrast which can be obtained. Polyimide foils are, in addition, deformable and can be produced easily in different shapes, whereby the shapes normally employed for supports of fluorescent screens may be easily obtained, for example, hemispheres which are usually employed with vacuum image intensifiers.
  • Fluorescent screens having a polyimide foil as the support may be united with the glass flasks used in image intensifiers, as well as with other materials, in a manner resisting high vacuum and temperature by the use of various adhesives, e.g., polyimide lacquers and polysiloxanes. In this manner, it is possible to obtain good optical contact while substantially avoiding reflecting surfaces. As a result of the avoidance of reflections, an additional improvement in the image is obtained. It is an additional advantage of the polyimide foils that they are gas-permeable.
  • An example of a polyimide foil which is suitable for use in the screen according to the invention may be a material obtained for example, by the polycondensation of a tetrabasic aromatic acid with an aromatic diamine. Because of the favorable combination of mechanical and electrical properties, there are especially suitable for the use as supporting foils for example are produced by polycondensation of at least one of the group including 2,3,6,7-naphthalene tetracarbonic acid dianhydride, 3,3',4,4'-diphenyltetracarbonic acid dianhydride, 2,6-dichloronaphthalene-1,4,5,8-tetracarbonic acid dianhydride, pyrrolidin-2,3,4,5-tetracarbonic acid dianhydride with at least one of the group including m-phenylenediamine, p-phenylenediamine, 4,4'-diamin0diphenylpropane, 4,4-diaminodiphenylmethane, 4,4'-di
  • a photocathode 3 is disposed behind a ray-entry window 4 in an evacuated glass flask 2. Behind the cathode 3 are electrodes 5 and 6, which consist of sheet metal strips bent in the form of a ring.
  • a fluorescent screen 8 is situated adjacent an end window 7 of the flask 2, which is opposite the entry window 4.
  • An anode 9 is disposed in front of the fluorescent screen 8 and faces the interior of the flask.
  • the anode 9, photocathode 3 and electrodes 5 and 6 constitute the electron-optical system of the image intensifier.
  • the photocathode 3 consists of a polyimide support 10 which has a thickness of less than 10p. and which is covered on that surface facing the window 4 with a fluorescent layer 11 which contains a polysiloxane binder in addition to cadmium sulfide which acts as the fluorescent substance.
  • the free surface of the fluorescent layer 11 is covered with a reflecting layer 12 consisting of a white pigment, in this case magnesium oxide.
  • a photocathode layer 13 consisting of antimony activated with caesium.
  • the photocathode 3 is fixed on the walls of the flask 2 by means of holder devices, two of which 14 and 15 are shown on two sides of the photocathode 3.
  • the fluorescent screen 8 comprises a support 16, a fluorescent layer 17 which contains silver-activated zinc-cadmium sulfide and silicon dioxide (as a-binder), and an aluminum layer 18.
  • the complete screen 8 is arranged so that the free surface of the support 16, with the aid of an adhesive layer 19 consisting of polyimide lacquer, is in good optical contact on the inside of the end wall 7 of the flask 2.
  • the intensifier enables an X-ray image to be made visible.
  • the X-rays pass through the window 4 into the flask 2 where they penetrate the reflecting layer 12 and generate mainly light in the fluorescent layer 11.
  • This light passes through the transparent support and produces an electron image in the photocathode layer 13, corresponding to the light distribution.
  • Suitable voltages applied in a known manner to the electrodes 5, 6 and the anode 9, as well as to the cathode 3, cause an electron image to be formed on the screen 8, where they produce in the layer 17 the intensified fluorescing and visible image.
  • a vacuum image intensifier which comprises an evacuated flask in which are contained (a) a photocathode disposed behind a ray-entry window of the evacuated flask and including a support on that side of which facing the ray-entry window is disposed a layer of a substance capable of fluorescing and on that side of which remote from the ray-entry window is disposed a layer of a substance capable of photoemission; (b) an electrode capable, in use, of accelerating electrons emitted at the photocathode; (c) an electrode capable, in use, of focusing said electrons: and (d) an electron-reactive screen which comprises a support on which is disposed a layer of a substance capable of fluorescing, characterized in that the support of said electron-reactive screen is formed of a polyimide, said polyimide being formed by the condensation of a tetrabasic aromatic acid which is at least one of the group including 2,3,6,7-naphthalene tetracarbonic
  • aromatic diamine which is at least one of the group including m-phenylcnediamine, p-phenylenediamine, 4,4-diaminodiphenylpropane, 4,4'-diaminodiphenylmethane 4,4'-diaminonaphthalene, 1,5-diaminonaphthanlene,

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  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • High Energy & Nuclear Physics (AREA)
  • Image-Pickup Tubes, Image-Amplification Tubes, And Storage Tubes (AREA)
US812543A 1968-03-14 1969-03-11 Image intensifier including polyimide support Expired - Lifetime US3617791A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE19681622999 DE1622999C3 (de) 1968-03-14 Leuchtschirm, insbesondere zur Verwendung in Bildwandler- oder Bildverstärkerröhren

Publications (1)

Publication Number Publication Date
US3617791A true US3617791A (en) 1971-11-02

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Family Applications (1)

Application Number Title Priority Date Filing Date
US812543A Expired - Lifetime US3617791A (en) 1968-03-14 1969-03-11 Image intensifier including polyimide support

Country Status (3)

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US (1) US3617791A (enrdf_load_stackoverflow)
FR (1) FR2003856A1 (enrdf_load_stackoverflow)
GB (1) GB1198597A (enrdf_load_stackoverflow)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3846654A (en) * 1972-03-15 1974-11-05 Siemens Ag Vacuum image converter
US3885188A (en) * 1972-03-17 1975-05-20 Matsushita Electric Ind Co Ltd Target assembly for storage tubes and a method of making the same
FR2786315A1 (fr) * 1998-11-24 2000-05-26 Siemens Ag Intensificateur d'images de rayons x, technique de montage par collage et son procede de fabrication

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2195062B1 (enrdf_load_stackoverflow) * 1972-08-02 1976-03-12 Labo Electronique Physique
US4623820A (en) 1984-05-07 1986-11-18 Rca Corporation CRT with carbon-particle layer on a metallized viewing screen
FR2629267B1 (fr) * 1988-03-22 1996-01-26 Thomson Csf Dispositif de conversion chromatique d'une image obtenue en rayonnement electromagnetique et procede de fabrication correspondant
EP4293574A3 (en) 2017-08-08 2024-04-03 RealD Spark, LLC Adjusting a digital representation of a head region
EP4001458B1 (fr) 2020-11-17 2024-10-16 The Swatch Group Research and Development Ltd Procede de depot d'un revetement sur un composant horloger et composant horloger revetu par un tel procede

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2945976A (en) * 1957-12-10 1960-07-19 Gen Electric Electroluminescent lamp and manufacture thereof
US3254252A (en) * 1962-01-24 1966-05-31 Westinghouse Electric Corp Image device
US3403279A (en) * 1965-09-04 1968-09-24 Philips Corp X-ray converter having terbium activated lanthanum compound phosphor

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2945976A (en) * 1957-12-10 1960-07-19 Gen Electric Electroluminescent lamp and manufacture thereof
US3254252A (en) * 1962-01-24 1966-05-31 Westinghouse Electric Corp Image device
US3403279A (en) * 1965-09-04 1968-09-24 Philips Corp X-ray converter having terbium activated lanthanum compound phosphor

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
Deshotels et al; Chemical Abstracts, Vol. 65, 1966; 14581 d *

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3846654A (en) * 1972-03-15 1974-11-05 Siemens Ag Vacuum image converter
US3885188A (en) * 1972-03-17 1975-05-20 Matsushita Electric Ind Co Ltd Target assembly for storage tubes and a method of making the same
FR2786315A1 (fr) * 1998-11-24 2000-05-26 Siemens Ag Intensificateur d'images de rayons x, technique de montage par collage et son procede de fabrication

Also Published As

Publication number Publication date
DE1622999A1 (de) 1971-01-14
FR2003856A1 (enrdf_load_stackoverflow) 1969-11-14
GB1198597A (en) 1970-07-15
DE1622999B2 (de) 1976-12-30

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