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Патент USA US3089964

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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.
Conductive (Boating
8
5
Fig 2
Photogmissive
Matenal
Photoemissive
Material
8
WITNESSES:
INVENTOR
Walter J. Hushley.
ATTORNEY
United States Patent O?ice
3,Q89,956
Patented May 14, 1963
1
3,089,956
X-RAY FLUORESCENT SCREEN
Walter J. Hushley, now by change of name Walter John
Harper, Pittsburgh, Pa, assignor to Westinghouse Elec
tric Corporation, East Pittsburgh, Pa, a corporation of
Pennsylvania
Filed July 10, 1953, Ser. No. 367,167
10 Claims. (Cl. 25tt—80)
2
with a transverse septum about 2 mils thick of the afore
said 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 con
densation, 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
?lled with zinc sulphide-silver or other suitable phos
phor 6 such as that known under the trade name of Pat
My invention relates to ?uorescent screens and in par 10 terson B (sold by du Pont de Nemours, Wilmington,
ticular relates to a screen comprising both ?uorescent
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
Delaware). This phosphor may comprise particles of
about 45 microns average diameter and an amount of
200 to 250 mg. per square centimeter would ?ll the above
described sockets. The remaining face of the sockets
useful in image intensi?ers, of which one typical example 15 should be covered by a metal foil 7 such as aluminum
is to be found in Coltman and Mason’s U.S. Patent
about one mil thick. Adjacent the conductive coating 5
2,523,132 issued September 19, 1950 and assigned to
is shown a layer 8 of a suitable photoemissive material
the assignee of this application.
such as that disclosed in the above-mentioned Coltman
In image intensi?ers of the type just referred to an X
and Mason U.S. Patent 2,523,132.
ray beam after passing through a pictured object is in 20
FIG. 2 shows another form of screen in accordance
cident 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
with my invention in which the square sockets of the
FIG. 1 screen are replaced by square holes passing com
pletely through the glass frame. The dimensions of the
rim, side walls, coatings and openings may be the same
the photoelectric material to emit electrons, thus forming 25 as in FIG. 1. A separate thin sheet 11 of glass covers
an electron image which is accelerated electrically into
incidence on an electron-phosphor screen where it pro
duces a bright light image in replica of the X-ray dis
tribution.
To attain a true reproduction of the ?uorescent 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 convert
ing X-ray or other radiation images into electron images.
Another object is to provide an improved type of im
age screen for electronic image intensi?er tubes.
Still another object is to provide an improved structure
for mouting ?uorescent materials in close contiguity to
the concave face of the screen openings, and its outer
face is coated with a transparent conductive layer 5. The
holes are ?lled as in FIG. 1 with the phosphor 6 above
described and their free face covered with the aluminum
foil '7 as before. The use of a thin layer of glass be
tween the aluminum layer 7 and the phosphor is also with
in the contemplation of my invention. Adjacent the con
ductive coating 5 is shown a layer 8 of a suitable photo
emissive material such as that disclosed in the above
35 mentioned 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 modi?ed structure in which the walls of
the holes 3 are tapered.
I claim as my invention:
1. In an image ampli?er, an input screen comprising
a foraminated plate member of insulating material, said
photoelectrically emissive material.
plate member having a foraminated surface and a non
Other objects of my invention will become apparent
foraminated surface, said plate member including a thin
upon reading the following description taken in connec 45 septum of said insulating material transverse to the fo
tion with the drawings in which:
raminations therein, a layer of transparent conductive
FIG. 1 is a mid-cross-sectional view of one form of
material upon said non foraminated surface of said
image screen embodying the principles of my invention;
plate member, ?uorescent material ?lling each of said
FIG. 2 is a similar view of another form of image
foraminations and a thin metallic member upon said
screen in which such principles may be embodied; and 50
foraminated
surface of said plate member, said thin sep
FIG. 3 is a similar view of a modi?ed image screen.
tum having a thickness of less than 10 percent of the
Referring in detail to FIG. 1, the main body of the
thickness of said plate member.
screen comprises the special glass which is becoming
2. In an image ampli?er, an input screen comprising
known as chemically machined glass, and is sold by the
Corning Glass Company of Corning, New York. For 55 a foraminated plate member of insulating material, said
plate member having a foraminated surface and a non
the image screens to be used in X-ray image intensi?ers
foraminated surface, said plate member including a thin
currently marketed by applicant’s assignee it may have the
septum of said insulating material transverse to the fo
form of a segment, six inches in diameter, of the sur
raminations therein, a layer of transparent conductive
face of an eleven inch radius sphere. A peripheral rim
1 about half an inch wide and 50 mils thick gives strength 60 material upon said non-foraminated surface of said plate
member, a layer of photoelectric material upon said
and rigidity, while a grid of ribs 2 of the same thickness
layer of transparent conductive material, ?uorescent ma
and 2 mils wide, enclosing square sockets 3 which are
terial ?lling each of said foraminations to obtain a ?uo
63 mils on a side and 48 mils deeps, cross-connects points
rescent image therein, said thin septum being of a thick
on this rim. The method I am acquainted with at the
moment for making such a foraminated glass structure is 65 ness to provide a true reproduction of said ?uorescent
image on said photoelectric layer and a thin metallic
by etching the sockets with a chemical reagent such as
member upon said foraminated surface of said screen
hydro?uoric acid in a spherical segment of the above-de
member.
scibed glass 50 mils thick. This etching method is de
3. In an image ampli?er, an input screen comprising
scribed in detail in Industrial and Engineering Chemistry,
vol. 45, page 115, January 1953 and some previous ar 70 a foraminated plate member of insulating material, said
ticles, but any other method of producing a rigid struc~
plate member having a foraminated surface and a non
ture having sockets of about the same dimensions each
foraminated surface, said plate member including a thin
3,089,956
3
4
septum of said insulating material transverse to the foram
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 ?uores
cent material ?lling each of ‘said foraminations to obtain
1
inations 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, ?uorescent ma
terial ?lling each of said foraminations, and a thin metal
lic member upon said foraminated surface of said screen
member, said thin septum having a thickness of less
than 10 percent of the thickness of said plate member.
4. In an image ampli?er, an input screen comprising
a foraminated plate member of insulating material, said
plate member having a foraminated surface and a non
foraminated surface, said plate member including a thin
septum of said insulating material transverse to the forarn‘
a ?uorescent image therein, said thin transparent septum
being of a thickness ‘to provide a true reproduction of
said ?uorescent image on said photoelectric layer.
8. In an image ampli?er, 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 ma
terial upon said non-foraminated surface and fluorescent
inations therein, a layer of transparent conductive ma 15 material ?lling each of said foraminations, said thin
transparent septum providing a barrier of minimum thick
terial upon said non‘foraminated surface of said plate
ness between said photoelectric mateiral and said ?uores
member, ?uorescent material ?lling each of said foram
cent material, said thin septum having a thickness of
inations, said foraminations having side wall portions, a
about two mils.
re?ecting surface lining said side wall portions of said
9. An intensifying screen for X~ray registrations com
foraminations, and a thin metallic member upon said 20
prising a honeycomb-shaped grid, the walls of which are
foraminated surface of said plate member.
light-re?ecting and the apertures of which are ?lled with
5. In an image ampli?er, an input screen comprising
a luminescent substance, said apertures being formed in
a foraminated plate member of insulating material, said
' a glass plate made of photographically sensitive glass
plate member having a foraminated surface and a non
foraminated surface, said plate member including a thin 25 and the partitions are coated with a light-re?ecting metal
layer.
septum of said insulating material transverse to the foram
10. An intensifying screen as claimed in claim 9, in
inations therein, a layer of transparent conductive ma
which the partitions are tapered on both sides.
terial upon said non-foraminated surface of said plate
member, a layer of photoelectric material upon said layer
of transparent conductive material, ?uorescent material 30
?lling each of said foraminations, said foraminations hav
ing side wall portions, a re?ecting surface lining said
side wall portions of said foraminations, and a thin metal
lic member upon said foraminated surface of said screen
35
member.
6. In an image ampli?er, an input screen comprising
a foraminated plate member of insulating material, said
plate member having a foraminated surface and a non
foraminated surface, said plate member including a thin 40
septum of said insulating material transverse to the fo
raminations therein, a layer of photoelectric material up
on the surface of said ?uorescent screen member opposite
said foraminated surface of said plate member, ?uorescent
material ?lling each of said foraminations, said foram 45
inations having side wall portions, a re?ecting surface
lining said side wall portions of said foraminations, and
a thin metallic member upon said foraminated surface
References Cited in the ?le of this patent
UNITED STATES PATENTS
1,467,132
2,029,639
2,303,563
Bilstein ______________ __ Sept. 4, 1923
Schlesinger ____________ .._ Feb. 4, 1936
Law ________________ __ Dec. 1, 1942
2,324,505
Iams et al _____________ __ July 20, 1943
2,501,376
2,523,132
2,555,545
2,567,714
Breadner et a1 _________ __ Mar. 21,
Mason et al ___________ __ Sept. 19,
Hunter et al. __________ __ June 5,
Kaplan _____________ __ Sept. 11,
1950
1950
1951
1951
2,582,822
Evans _______________ __ Jan. 15, 1952
2,583,000
2,606,299
Lytle ________________ __ Jan. 22, 1952
Coltman et al. ________ __ Aug. 5, 1952
2,660,686
Putnam _____________ __ Nov. 24, 1953
2,689,189
2,705,765
Hushley ____________ __ Sept. 14, 1954
Geer ________________ __ Apr. 5, 1955
2,739,243
Sheldon ____________ __ Mar. 20, 1956
of said plate member.
OTHER REFERENCES
7. In an image ampli?er, an input screen comprising 50
“Fluoroscopic
Image Brightening by Electronic Means,”
a plate member of insulating material having a plurality
Coltman, Radiology, v01. 51, September 1948, pp. 359—
of foraminations therein, said plate member including a
366.
thin transparent septum transverse to said foraminations
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