Search Images Maps Play YouTube News Gmail Drive More »
Sign in
Screen reader users: click this link for accessible mode. Accessible mode has the same essential features but works better with your reader.

Patents

  1. Advanced Patent Search
Publication numberUS3089956 A
Publication typeGrant
Publication date14 May 1963
Filing date10 Jul 1953
Priority date10 Jul 1953
Publication numberUS 3089956 A, US 3089956A, US-A-3089956, US3089956 A, US3089956A
InventorsJohn Harper Walter
Original AssigneeWestinghouse Electric Corp
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Chi-ray fluorescent screen
US 3089956 A
Abstract  available in
Images(1)
Previous page
Next page
Claims  available in
Description  (OCR text may contain errors)

May 14, 1963 7 3,089,956

WALTER J. HUSHLEY NOW BY CHANGE OF NAME WALTER JOHN HARPER X-RAY FLUORESCENT SCREEN Filed July 10, 1955 Fig. l.

Photogmissive Conductive (Boating 8 Matenal Material g 2 Photoemissive WITNESSES: INVENTOR Walter J. Hushley.

ATTORNEY United States Patent Ofiice 3,Q89,956 Patented May 14, 1963 3,089,956 X-RAY FLUORESCENT SCREEN Walter J. Hushley, now by change of name Walter John Harper, Pittsburgh, Pa, assignor to Westinghouse Electric Corporation, East Pittsburgh, Pa, a corporation of Pennsylvania Filed July 10, 1953, Ser. No. 367,167 Claims. (Cl. 25tt80) My invention relates to fluorescent screens and in particular relates to a screen comprising both fluorescent material and photoelectric material which is capable of transforming an X-ray or other radiation image into an electron image which is its replica. Such screens are useful in image intensifiers, of which one typical example is to be found in Coltman and Masons U.S. Patent 2,523,132 issued September 19, 1950 and assigned to the assignee of this application.

In image intensifiers of the type just referred to an X- ray beam after passing through a pictured object is incident upon a screen having a thin layer of zinc sulphide separated from a thin layer of photoelectric material by a thin layer of glass. The light generated by the X-rays in the zinc sulphide causes the closely adjacent areas of the photoelectric material to emit electrons, thus forming an electron image which is accelerated electrically into incidence on an electron-phosphor screen where it produces a bright light image in replica of the X-ray distribution.

To attain a true reproduction of the fluorescent image the separation between the zinc sulphide particles and the photoelectric particles should be as small as possible. In my present invention this is achieved by forming the body of the screen of a chemically machined glass on which the zinc sulphide is mounted.

One object of my invention is, accordingly, to provide a new and improved form of optical screen for converting X-ray or other radiation images into electron images.

Another object is to provide an improved type of image screen for electronic image intensifier tubes.

Still another object is to provide an improved structure for mouting fluorescent materials in close contiguity to photoelectrically emissive material.

Other objects of my invention will become apparent upon reading the following description taken in connection with the drawings in which:

FIG. 1 is a mid-cross-sectional view of one form of image screen embodying the principles of my invention;

FIG. 2 is a similar view of another form of image screen in which such principles may be embodied; and

FIG. 3 is a similar view of a modified image screen.

Referring in detail to FIG. 1, the main body of the screen comprises the special glass which is becoming known as chemically machined glass, and is sold by the Corning Glass Company of Corning, New York. For the image screens to be used in X-ray image intensifiers currently marketed by applicants assignee it may have the form of a segment, six inches in diameter, of the surface of an eleven inch radius sphere. A peripheral rim 1 about half an inch wide and 50 mils thick gives strength and rigidity, while a grid of ribs 2 of the same thickness and 2 mils wide, enclosing square sockets 3 which are 63 mils on a side and 48 mils deeps, cross-connects points on this rim. The method I am acquainted with at the moment for making such a foraminated glass structure is by etching the sockets with a chemical reagent such as hydrofluoric acid in a spherical segment of the above-descibed glass 50 mils thick. This etching method is described in detail in Industrial and Engineering Chemistry, vol. 45, page 115, January 1953 and some previous articles, but any other method of producing a rigid structure having sockets of about the same dimensions each with a transverse septum about 2 mils thick of the aforesaid glass is within the scope of my invention.

The sockets are coated inside on the transvense wall only with a thin layer 4 of aluminum, e.g., by vapor condensation, and the outer face of the glass is coated with a thin layer 5 of a transparent electrical conductor, e.g., by hot-spraying with tin chloride. The sockets are then filled with zinc sulphide-silver or other suitable phosphor 6 such as that known under the trade name of Patterson B (sold by du Pont de Nemours, Wilmington, Delaware). This phosphor may comprise particles of about 45 microns average diameter and an amount of 200 to 250 mg. per square centimeter would fill the abovedescribed sockets. The remaining face of the sockets should be covered by a metal foil 7 such as aluminum about one mil thick. Adjacent the conductive coating 5 is shown a layer 8 of a suitable photoemissive material such as that disclosed in the above-mentioned Coltman and Mason U.S. Patent 2,523,132.

FIG. 2 shows another form of screen in accordance with my invention in which the square sockets of the FIG. 1 screen are replaced by square holes passing completely through the glass frame. The dimensions of the rim, side walls, coatings and openings may be the same as in FIG. 1. A separate thin sheet 11 of glass covers the concave face of the screen openings, and its outer face is coated with a transparent conductive layer 5. The holes are filled as in FIG. 1 with the phosphor 6 abovedescribed and their free face covered with the aluminum foil '7 as before. The use of a thin layer of glass between the aluminum layer 7 and the phosphor is also within the contemplation of my invention. Adjacent the conductive coating 5 is shown a layer 8 of a suitable photoemissive material such as that disclosed in the abovementioned Coltman and Mason U.S. Patent 2,523,132.

The holes need not be square but may be of any shape and their size and number may also be varied. FIG. 3 illustrates a modified structure in which the walls of the holes 3 are tapered.

I claim as my invention:

1. In an image amplifier, an input screen comprising a foraminated plate member of insulating material, said plate member having a foraminated surface and a nonforaminated surface, said plate member including a thin septum of said insulating material transverse to the foraminations therein, a layer of transparent conductive material upon said non foraminated surface of said plate member, fluorescent material filling each of said foraminations and a thin metallic member upon said foraminated surface of said plate member, said thin septum having a thickness of less than 10 percent of the thickness of said plate member.

2. In an image amplifier, an input screen comprising a foraminated plate member of insulating material, said plate member having a foraminated surface and a nonforaminated surface, said plate member including a thin septum of said insulating material transverse to the foraminations therein, a layer of transparent conductive material upon said non-foraminated surface of said plate member, a layer of photoelectric material upon said layer of transparent conductive material, fluorescent material filling each of said foraminations to obtain a fluorescent image therein, said thin septum being of a thickness to provide a true reproduction of said fluorescent image on said photoelectric layer and a thin metallic member upon said foraminated surface of said screen member.

3. In an image amplifier, an input screen comprising a foraminated plate member of insulating material, said plate member having a foraminated surface and a nonforaminated surface, said plate member including a thin septum of said insulating material transverse to the foraminations therein, a layer of transparent conductive ma terial upon said non-foraminated surface of said plate member, a layer of photoelectric material upon said layer of transparent conductive material, fluorescent material filling each of said foraminations, and a thin metallic member upon said foraminated surface of said screen member, said thin septum having a thickness of less than percent of the thickness of said plate member.

4. In an image amplifier, an input screen comprising a foraminated plate member of insulating material, said plate member having a foraminated surface and a nonforaminated surface, said plate member including a thin septum of said insulating material transverse to the forarn inations therein, a layer of transparent conductive material upon said nonforaminated surface of said plate member, fluorescent material filling each of said foraminations, said foraminations having side wall portions, a reflecting surface lining said side wall portions of said foraminations, and a thin metallic member upon said foraminated surface of said plate member.

5. In an image amplifier, an input screen comprising a foraminated plate member of insulating material, said plate member having a foraminated surface and a nonforaminated surface, said plate member including a thin septum of said insulating material transverse to the foraminations therein, a layer of transparent conductive material upon said non-foraminated surface of said plate member, a layer of photoelectric material upon said layer of transparent conductive material, fluorescent material filling each of said foraminations, said foraminations having side wall portions, a reflecting surface lining said side wall portions of said foraminations, and a thin metallic member upon said foraminated surface of said screen member.

6. In an image amplifier, an input screen comprising a foraminated plate member of insulating material, said plate member having a foraminated surface and a nonforaminated surface, said plate member including a thin septum of said insulating material transverse to the foraminations therein, a layer of photoelectric material upon the surface of said fluorescent screen member opposite said foraminated surface of said plate member, fluorescent material filling each of said foraminations, said foraminations having side wall portions, a reflecting surface lining said side wall portions of said foraminations, and a thin metallic member upon said foraminated surface of said plate member.

7. In an image amplifier, an input screen comprising a plate member of insulating material having a plurality of foraminations therein, said plate member including a thin transparent septum transverse to said foraminations so that said plate member has a foraminated surface and a non-foraminated surface, a layer of photoelectric material upon said non-foraminated surface and fluorescent material filling each of said foraminations to obtain a fluorescent image therein, said thin transparent septum being of a thickness to provide a true reproduction of said fluorescent image on said photoelectric layer.

8. In an image amplifier, an input screen comprising a plate member of insulating material having a plurality of foraminations therein, said plate member including a thin transparent septum transverse to said foraminations so that said plate member has a foraminated surface and a non-foraminated surface, a layer of photoelectric material upon said non-foraminated surface and fluorescent material filling each of said foraminations, said thin transparent septum providing a barrier of minimum thickness between said photoelectric mateiral and said fluorescent material, said thin septum having a thickness of about two mils.

9. An intensifying screen for X-ray registrations comprising a honeycomb-shaped grid, the walls of which are light-reflecting and the apertures of which are filled with a luminescent substance, said apertures being formed in a glass plate made of photographically sensitive glass and the partitions are coated with a light-reflecting metal layer.

10. An intensifying screen as claimed in claim 9, in which the partitions are tapered on both sides.

References Cited in the file of this patent UNITED STATES PATENTS 1,467,132 Bilstein Sept. 4, 1923 2,029,639 Schlesinger Feb. 4, 1936 2,303,563 Law Dec. 1, 1942 2,324,505 Iams et al July 20, 1943 2,501,376 Breadner et a1 Mar. 21, 1950 2,523,132 Mason et al Sept. 19, 1950 2,555,545 Hunter et al. June 5, 1951 2,567,714 Kaplan Sept. 11, 1951 2,582,822 Evans Jan. 15, 1952 2,583,000 Lytle Jan. 22, 1952 2,606,299 Coltman et al. Aug. 5, 1952 2,660,686 Putnam Nov. 24, 1953 2,689,189 Hushley Sept. 14, 1954 2,705,765 Geer Apr. 5, 1955 2,739,243 Sheldon Mar. 20, 1956 OTHER REFERENCES Fluoroscopic Image Brightening by Electronic Means, Coltman, Radiology, v01. 51, September 1948, pp. 359 366.

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US1467132 *17 Jan 19224 Sep 1923United States Radium CorpApplication of luminous compounds
US2029639 *23 Dec 19324 Feb 1936Kurt SchlesingerBraun tube
US2303563 *9 May 19411 Dec 1942Rca CorpCathode ray tube and luminescent screen
US2324505 *6 Feb 194220 Jul 1943Rca CorpTelevision transmitting tube and electrode structure
US2501376 *25 Feb 194621 Mar 1950Gen ElectricElectric discharge lamp
US2523132 *10 Aug 194919 Sep 1950Westinghouse Electric CorpPhotosensitive apparatus
US2555545 *28 Aug 19475 Jun 1951Westinghouse Electric CorpImage intensifier
US2567714 *21 Dec 195011 Sep 1951Sightmaster CorpCathode-ray tube
US2582822 *4 Dec 194815 Jan 1952Rca CorpCathode-ray tube with aluminized screen
US2583000 *14 May 194622 Jan 1952Pittsburgh Plate Glass CoTransparent conducting films
US2606299 *11 Mar 19505 Aug 1952Westinghouse Electric CorpImage intensifier tube
US2660686 *19 Jun 194824 Nov 1953Westinghouse Electric CorpFluorescent screen
US2689189 *5 Dec 195114 Sep 1954Westinghouse Electric CorpX-ray fluorescent screen
US2705765 *3 Apr 19505 Apr 1955Willard Geer CharlesSingle gun color television receiving tube and screen structure
US2739243 *8 Jan 195320 Mar 1956Emanuel Sheldon EdwardComposite photosensitive screens
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US3291706 *8 Oct 196313 Dec 1966Gebel Radames K HMethod of making an optical fiber phosphor screen
US3344276 *30 Mar 196426 Sep 1967Kaiser Aerospace & ElectronicsRadiographic screen having channels filled with a material which emits photons when energized by gamma or x-rays
US3482104 *24 May 19652 Dec 1969Finkle JackSystem for televising radiant energy images employing image transducer device with radiant energy image responsive photocathode
US3717764 *5 Mar 197020 Feb 1973Fuji Photo Film Co LtdIntensifying screen for radiograph use
US3753714 *23 Nov 197021 Aug 1973Fuji Photo Film Co LtdImage formation by radiation and intensification
US4096381 *19 Jul 197620 Jun 1978Brown Sr Robert LElectron image detection system
US4208577 *10 Aug 197817 Jun 1980Diagnostic Information, Inc.X-ray tube having scintillator-photocathode segments aligned with phosphor segments of its display screen
US4209705 *10 Mar 197824 Jun 1980Tokyo Shibaura Electric Co, Ltd.Image intensifier whose input screen phosphor layer is divided into light guiding mosaic blocks by metal protrusions
US4317037 *11 Jun 197923 Feb 1982Hitachi, Ltd.Radiation detection apparatus
US4339659 *20 Oct 198013 Jul 1982International Telephone And Telegraph CorporationImage converter having serial arrangement of microchannel plate, input electrode, phosphor, and photocathode
US4415810 *5 Jul 197915 Nov 1983Brown Sr Robert LDevice for imaging penetrating radiation
US4778565 *12 Nov 198718 Oct 1988Picker International, Inc.Method of forming panel type radiation image intensifier
US4855589 *12 Nov 19878 Aug 1989Picker International, Inc.Panel type radiation image intensifier
US4935617 *27 Feb 198919 Jun 1990Kabushiki Kaisha ToshibaX-ray image intensifier and method of manufacturing the same
US5338926 *22 May 199216 Aug 1994Kabushiki Kaisha ToshibaX-ray imaging tube having a light-absorbing property
US5445846 *28 Feb 199429 Aug 1995Kabushiki Kaisha ToshibaX-ray imaging tube
Classifications
U.S. Classification250/486.1, 976/DIG.439, 250/214.0VT
International ClassificationH01J29/38, H01J29/24, G21K4/00, H01J29/18, H01J29/10
Cooperative ClassificationH01J29/24, H01J29/385, G21K4/00
European ClassificationH01J29/38B, H01J29/24, G21K4/00