close

Вход

Забыли?

вход по аккаунту

?

Патент USA US3052818

код для вставки
Sept. 4, 1962
H. BAHRING ET AL
3,052,809
FOCUSING SYSTEM FOR STORAGE TUBES WITH IMAGE SECTION
Filed Sept. 14, 1959
lb 2b 3?; 4'0 5'0 627 rbléo 9'0 100 ‘
Cathode
—> mm
7Zirgrez‘
Fi'g. Z
Jn vem‘o rs:
Herbert Bb'fring
Friedrich Bender
by gay“! 1. JAM/'2”
Attorney
3,952,809
‘ate
Patented Sept. 4, 1962
2
1
the image increases with increasing gap width from 20%
to 60%, that is, to twice the resolution obtained without
3,052,809
WITH ]1VIA_GE SECTION
FOCUSING SYSTEM FOR STORAGE TUBES
Herbert Bahring, Darmstadt, and Friedrich Bender,
r
Weiterstadt, near Darmstadt, Germany, assignors to
Fernseh G.ni.h.H., Darinstadt, Germany
the screening sheath, and then falls with increasing vgap
width to 35%. The length of the gap shown on the
abscissa of the graph is measured from the photo-cathode
end of the tube. The nature of this effect can be ex;
plained on the assumption that two in?uences are effec*
Filed Sept. 14, 1959, Ser. No. 839,802
tive, namely the additional screening of the conducting
Claims priority, application Germany Sept. 13, 1958
sheath and the reduction of eddy current in?uences by
the separating gap.
The line 10 running horizontally at about 28% indi
9 Claims. (Cl. 313-84)
When using storage tubes having an image section
and a long focusing coil it was formerly usual to pro
cates the resolution which would be obtained, as ex~
the lines of force together in a restricted space, so that
to 20 mm. in the aluminium cylinder are situated at dis
tances of 10 to 20 mm. from the target.
The use of an aluminium sheath on the focusing coil
pl-ained above, with a focusing coil without aluminium
vide between the de?ection system and the focusing coil
screening. The further short lines 7, 8 and 9 show the
a screening cylinder of ferromagnetic material, for ex
ample, mumetal. The purpose of this cylinder is to keep 15 resolution which is obtained if only short gaps of 10
any stray ?eld is suppressed and the de?ection power
which is necessary is reduced. It would be expected,
has also proved advantageous in another respect. This
however, that despite the screening lines of ‘force of the
de?ection ?eld encroach into the image converter sec 20 is, that the heat can easily be conducted by this sheath
from the interior of the coil to the exterior, so that the
tion of the pickup tube and there ‘give rise to a lack of
problems of maintaining a constant temperature and of
de?nition in the formation of the image, which becomes
cooling the pickup tube can more easily be solved.
apparent as a reduced resolution of the camera. In an
The invention is not limited to sheathing the outer
RCA type 5820 image orthicon, for example, a resolution
and inner surfaces of the coil completely with metal.
of about 28% of the black-white amplitude is obtained
It may in some cases be advantageous to provide only
at 5 mc./s., that is, on scanning a pattern of black and
an inner lining of non-magnetic material, with the gap
white bars the amplitude of the picture signal variation
mentioned above. In addition a further substantial in
crease in the resolution can in case of need be obtained
for bars set at a pitch which on scanning yields a ‘fre
quency of 5 mc./s., amounts to only 28% of the signal
amplitude for patterns of larger pitch where the ampli~
30
tude corresponds to the full difference between black
and white.
by employing also additional compensating coil at the
photo-cathode end of the image converter section and
feeding these with a current of sawtooth form.
The size of the focused scanning spot in
In this
case, compensation for the distortions resulting from the
lines of force of the de?ection space encroaching directly
the pickup tube, on the other hand, is such as to make
possible a higher resolution. ‘It is thus apparent that
despite the screening, there must still be some effect due
into the image section can readily be effected, since the
distortion of the de?ection fields by eddy currents is
reduced. By this means the range of application of the
image-orthicon tube may be extended to numbers of
lines for which the tube was originally unsuitable. By
to the stray ?eld.
Various ways of reducing this distortion have been
investigated. It has, for example, been proposed to pro
vide the image converter section with an auxiliary coil
which generates a compensating de?ection ?eld. To carry 40 using the latter means a distinct improvement of the
resolution to 8 mc./ s. is attained. '
this into practice, however, proves to be relatively dif
What is claimed as new and ‘desired to be secured by
?cult, since the frequency spectrum of the stray ?eld is
Letters Patent is:
different from that of the original de?ection ?eld owing
l. A focusing and de?ection system for a storage tube
to the effect of eddy currents, so that the current ?owing
of the image orthicon type having a cathode ray section
in the compensating coils cannot ‘be the same as in the
45
main de?ecting coils.
It has now been found that the quality of image forma
tion can be substantially improved if the interior, and
preferably also the exterior, of the focusing coil is clad
and an image section, comprising, in combination, de?ec~
tion coil means arranged within an annular space sur
rounding the cathode ray section; focusing coil means
surrounding at least the cathode ray section and said
de?ection coil means; and electrically continuous tubular
with a sheath of highly conductive material, e.g., copper 50
screen means of electrically highly conductive non-mag
or aluminium, an interruption or separating joint being
netic material arranged at least between said focusing
provided in the inner part of the screening sheath, at
coil means and said de?ection coil means and surround
that position at which the transition occurs between the
ing at least said cathode ray section, for improving the
image section of the pickup tube and the de?ection space.
Alternatively, the whole of the interior of the coil in the 55 resolution of the tube by elimination of stray ?eld effects
in the image section.
region of the image section may be free from the screen‘
2. A focusing and de?ection system for a storage tube
ing material.
of the image orthicon type having a cathode ray section
FIGURE 1 shows an embodiment of the invention. In
and an image section, comprising, in combination, de?ec
this ?gure, 1 is an image-orthicon pickup tube, on the
neck of which are placed the de?ection coils 2 and the 60 tion coil means arranged within an annular space sur
rounding the cathode ray section; focusing coil means
ferromagnetic sheath 3. The tube is completely sur
rounded by a vlong focusing coil 4. Numeral 5 indicates
the screening sheath of the focusing coil, which is inter
rupted at 6 by a gap which extends over almost the
surrounding the cathode ray section, at least part of the
length of the image section and said de?ection coil means;
and electrically continuous tubular screen means of elec
whole length of the image section.
trically highly conductive non-magnetic material arranged
an image-orthicon camera depends upon the length of
?cction coil means and surrounding at least said cathode
65 at least between said focusing coil means and said de
FIGURE 2 is a graph showing how the resolution of
ray section and the part of the image section which is
surrounded by said focusing coil means, said tubular
pletely closed upon itself gives rise to a reduction in
resolution from 28 to 20%. If, on the other hand, ‘a 70 screen means being composed of at least two coaxial
electrically continuous tubular portions axially spaced
gap is provided in the inner surface of the sheath in the
from each other at least in the area of the tube where
region of the image converter section, the resolution of
the gap in the sheath.
It can be seen that a sheath com
4
the transition from cathode ray section to image section
occurs, for improving the resolution of the tube by elimi
nation of stray ?eld effects in the image section.
3. A focusing and de?ection system for a storage tube
of the image orthicon type having a cathode ray section
and an image section, comprising, in combination, de?ec
tion coil means arranged within an annular space sur
rounding the cathode ray section; focusing coil means
surrounding the cathode ray section, at least the length
ranged between said focusing coil means and said de?ec
tion coil means and surrounding at Ileast said cathode ray
section and the image section, said second portion of
said tubular screen means being composed of at least two
electrically continuous coaxial tubular portions axially
spaced ‘from each other to form an annular gap‘ there—
between which starts in the area of the tube where the
transition from cathode ray section to image section oc
curs and extends over at least part of the length of said
of the image section and said de?ection coil means; and 10 image section, for improving the resolution of the tube
electrically continuous tubular screen means of electrically
by elimination of stray ?eld effects in the image section.
highly conductive non-magnetic material arranged at
7. A focusing and de?ection system for a storage tube
least between said focusing coil means and said deflection
of the image orthicon type having a cathode ray section
coil means and surrounding at least said cathode ray sec
and an image section, comprising, in combination, de
tion and the image section, said tubular screen means 15 ?ection coil means arranged within an annular space
being composed of at least two electrically continuous
coaxial tubular portions axially spaced from each other
surrounding the cathode ray section; focusing coil means
surrounding the cathode ray section, at least the length
of the image section and said de?ection coil means; and
at least in the area of the tube where the transition from
cathode ray section to image section occurs, for improv
tubular screen means of electrically highly conductive
ing the resolution of the tube by elimination of stray ?eld 20 non-magnetic material having a first portion surrounding
effects in the image section.
said focusing coil means and a second portion arranged
4. A focusing and de?ection system for a storage tube
between said focusing coil means and said de?ection coil
of the image orthicon type having a cathode ray section
means and surrounding at least said cathode ray section
and an image section, comprising, in combination, de?ec
and the image section, said second portion of said tubular
tion coil means arranged within an annular space sur
screen means being composed of at least two coaxial
rounding the cathode ray section; focusing coil means
electrically continuous tubular portions axially spaced
surrounding the cathode ray section, at least the length
from each other to form an annular gap therebetween
of the image section and said de?ection coil means; and
which starts in the area of the tube where the transition
tubular screen means of electrically highly conductive
from cathode ray section to image section occurs and
30
non-magnetic material having a ?rst portion surround
extends over at least part of the length of said image
ing said focusing coil means and a second portion ar
section, said ?rst ‘and second portions of said tubular
ranged between said focusing coil means and said de?ec
screen means having annular end portions joining said
tion coil means and surrounding at least said cathode ray
?rst and second portions with each other [and covering
section and the image section, said second portion of
the respective ends of said focusing coil means, for im
said tubular screen means being composed of at least two 35 proving the resolution of the tube by elimination of stray
coaxial electrically continuous tubular portions axially
?eld effects in the image section.
spaced from each other at least in the area of the tube
8. A focusing and de?ection system for a storage tube
where the transition from cathode ray section to image
of the image orthicon type having a cathode ‘ray section
section occurs, for improving the resolution of the tube
and an image section, comprising, in combination, de
by elimination of stray ?eld effects in the image section. 40 ?ection coil means arranged within an annular space
5. A focusing and de?ection system for a storage tube
surrounding the cathode ray section; focusing coil means
of the image orthicon type having a cathode ray section
surrounding the cathode ray section, at least the length
and an image section, comprising, in combination, de?ec
of the image section and said de?ection coil means; and
tion coil means arranged within an annular space sur
tubular screen means of electrically highly conductive
rounding the cathode ray section; focusing coil means 45 non-magnetic material having a ?rst portion surrounding
surrounding the cathode ray section, at least the length
said focusing coil means and a second portion arranged
of the image section and said de?ection coil means; and
between said focusing coil means and said de?ection
tubular screen means of electrically highly conductive
non-magnetic material having a ?rst portion surround
ing said focusing coil means and a second portion ar
ranged between said focusing coil means and said de?ec
tion coil means and surrounding at least said cathode ray
section and the image section, said second portion of
said tubular screen means “being composed of at least two
coaxial electrically continuous tubular portions axially
coil means ‘and surrounding at least said cathode ray
section and the image section, said second portion of
said tubular screen means being composed of at least
two coaxial electrically continuous tubular portions axial
ly spaced from each other to form an annular gap there
between which starts in the area of the tube where the
transition from cathode ray section to image section
occurs and extends over the length of said image section,
spaced from each other at least in the area of the tube
for improving the resolution of the tube by elimination
where the transition from cathode ray section to image
of stray ?eld effects in the image section.
section occurs, said ?rst and second portions of said tu
9. A focusing and de?ection system for a storage tube
bular screen means having annular end portions joining 60
of the image orthicon type having a cathode ray section
said ?rst and second portions with each other and cover—
ing the respective ends of said focusing coil means, for
improving the resolution of the tube by elimination of
stray ?eld effects in the image section.
and an image section, comprising, in combination, de
?ection coil means arranged ‘within an annular space
surrounding the cathode ray section; focusing coil means
surrounding the cathode ray section, at least the length
-6. A focusing and de?ection system for a storage tube 65
of the image section and said de?ection coil means; and
of the image orthicon type having a cathode ray section
tubular screen means of electrically highly conductive
and an image section, comprising, in combiniation, de?ec
non-magnetic material having a ?rst portion surrounding
tion coil means arranged within an annular space sur
said focusing coil means and a second portion arnanged
rounding the cathode ray section; focusing coil means
between said focusing coil means and said de?ection coil
surrounding the cathode ray section, at least the length 70 means and surrounding at least said cathode ray section
of the image section and said de?ection coil means; and
and the image section, said second portion of said tubu
tubular screen means of electrically highly conductive
non-magnetic material having a ?rst portion surround
ing said focusing coil means and a second portion ar
lar screen means being composed of at least two coaxial
electrically continuous tubular portions axially spaced
75 from each other to form an annular gap therebetween
3,052,809
5
which starts in the area of the tube where the transition
from cathode ray section to image section occurs and ex
tends over the length of said image section, said ?rst and
second portions of said tubular screen means having
annular end portions joining said ?rst and second portions 5
with each other and covering the respective ends of said
focusing coil means, for improving the resolution of the
tube by elimination of stray ?eld effects in the image
section.
6
References Cited in the ?le of this patent
UNITED STATES PATENTS
2,887,594
Federmann __________ __ Sept. 12, 1939
ROse _______________ __ Nov. 11, 1952
Rotow _____________ __ May 19, 1959
715,482
Great Britain ________ __ Sept. 15, 1954
2,172,733
2,617,954
FOREIGN PATENTS
Документ
Категория
Без категории
Просмотров
0
Размер файла
444 Кб
Теги
1/--страниц
Пожаловаться на содержимое документа