Dec, 4, 1945.
2,390,250
c, w. HANSELL
CATHODE RAY TUBE AND CIRCUIT
Filed Nov. 3, 1942
2 Sheets-Sheet 1
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INVENTOR.
CLARENCE 14/. HANSELL
BY
ATTORNEY.
Dec. 4, 1945.
2,390,250
-c. w. HANSELL ‘
CATHODE RAY TUBE AND CIRCUIT
Filed Nov. 5, 1942
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2 Sheets-Sheet 2
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INVENTOR
C/L?k’F/VCE m f/?/VJEZL
BY
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W
ATTORNEY
Patented Dec. 4, 1945
2,390,256
UNITED STATES PATENT QFFTCE
2,390,250
CATHODE RAY TUBE AND CIRCUIT
Clarence W. Hansell, Port Je?'erson, N. Y., as
signor to Radio Corporation of America, a cor
poration of Delaware
_
Application November 3, 1942, Serial No. 464,325
6 Claims. (Cl. 250—151)
.
This invention relates to improvements in
cathode ray type electron discharge devices and
circuits therefor, and particularly concerns a
cathode ray device wherein an electron stream
a de?ecting plate electrode 3, a pair of rod-like
electrodes 4, 4 symmetrically positioned on oppo
site sides of the axis of the tube, a metallic cylin
der 5 surrounding the rod electrodes 4, 4, a pair
of electron collectors or anodes 6, 6 and an axially
is shifted between .a pair of electron collecting
electrodes under the influence of a de?ecting 5 positioned shield or screen plate electrode 1 for
electric ?eld. The present invention is a conshielding the anodes from each other.
tinuation-in-part of my copending application
The cathode ray tube is illustrated as being
Serial No. 324,053, ?led March 15, 1940, now
used for the ampli?cation of alternating cur
United States Patent 2,305,617, granted December
rents, and has connected to it a suitable input
22, 1942. .
10 circuit 8 extending to a source of signal waves
An object of the present invention is to provide
an electronic ampli?er of alternating currents
which is extremely sensitive and has a large ratio
of controlled current and power to control cur-
to be ampli?ed, not shown, and coupled via a
parallel tuned circuit 9 to the de?ecting plate
electrode 3‘. The rod-like electrodes 4, 4 are each
maintained at a relatively high positive potential
rent and power.
15 with respect to the cathode over individual paths
Another object is to provide means for conwhich include leads [5, I5, resistors l0, l0 and
tinuously increasing the angular deflection of an
opposite sides of a potentiometer II to an inter
electron beam during the interval of travel from
the cathode to the electron collecting electrode.
A further object of the present invention is to
provide an electric ?eld for a cathode ray tube
of such con?guration that it continuously acts
on the electron beam over the major part of its
path of travel to increase the initial de?e‘ttion,
and is only effective after the beam has been
pulled off center.
A still further object is to provide a high frequency ampli?er of the electron beam type which
has' a greater sensitivity and greater control of
the current and power in the tube than conventional beam type tubes now in use.
These objects and others will be more readily
understood from a reading of the following de-
mediate point of which is connected a lead l2
extending to the positive terminal of a source
20 of unidirectional potential 25. The anodes 6, 6
are connected to the opposite terminals of po
tentiometer ll over individually tunable output
circuits [3, l3, the latter being coupled by means
. of transformer M to a suitable common utiliza
25 tion circuit, not shown. The shield 1, cylinder
5 and" de?ecting electrode 3 are maintained at
substantially the same positive potential relative
to the cathode although at a less positive poten
30 tial than the rods 4,.4 and anodes 6, 6.
The electric ?eld distribution between the rods
4, 4 and. cylinder 5 is shown in Fig. 2 which illus
trates a cross-section of the vacuum tube of Fig. 1
along the dash lines 2—2. In Fig. 2, the electron
scription which is accompanied by drawings, 35 beam which normally passes along the axis of
wherein:
the tube in the absence of de?ecting potentials,
Figs. 1, 4 and 6 illustrate dilferent embodiments
is shown by the dotted circular lines in the center
of cathode ray tubes embodying the principles
of the cylinder. It should be noted that the elec
ofthe invention;
tric ?eld is substantially zero along the axis of
Figs. 2 and 5 are fragmentary cross-section 40 the cylinder but increases rapidly between the
views of Figs. 1 and 4, respectively, showing the
axis and the rods 4, '4. Electrons traveling
positioning of the most important electrodes of
through the cylinder which are not on the ‘axis
the tubes and the electric ?eld distribution therewill therefore be de?ected by the electric ?eld
between;
toward one or the other of the rod-like elec
Fig. 3 illustrates a cross-section of a modi?ca- 45 trodes 4, 4. It Will be evident that when the elec
tion of the tube of Fig. 1; and
,
Fig. 7 is a fragmentary cross-section of a tube
showing electron paths and is given to aid in
an understanding of the operation of Fig. 6.
tron beam travels down the axis of the cylinder
5, its center line will be substantially unaffected
by the‘elect'ric ?eld within the cylinder. How
ever, if the beam is deflected off ‘the axis toward
Throughout the ?gures, the same or equivalent 50 one or the other of the rod-like electrodes 4, 4,
parts are represented by the same ‘reference
the beam will be-acted on by the electric ?eld to
numerals.
increase the deflection. Putting it another way,
Referring to Fig. l in more detail, there is
the initial de?ection of an electron toward one
shown a cathode ray tube having within an evacrod 4 will cause a greater movement toward said
uated envelope i,
electron emitting cathode 2, 5,5 one rod by virtue‘ of the positive’potential on this
2
rod.
2,390,250
The oppositely located rod 4 will not have
be evident that the ?eld distributions of Figs. 2,
3 and 5 are substantially similar and will cause
similar effects on the electron beam. In Fig. 4,
there is shown a tubular accelerating electrode
an exact counter attraction on this electron be
cause of the ?eld distribution shown in Fig. 2.
As soon as the electron is pulled or drawn off the
axis or center toward one rod electrode 4, the Cl
force on this electron increases in a direction
l6 which has integral therewith a circular shield
toward the said one rod.
In the operation of the device and circuit of
Fig. 1, the input energy on line 8 which is to be
ampli?ed, is impressed on tuned circuit 9 and
causes de?ecting electrode 3 to move the electron
I6 and plates I8, I8 have suitable positive polar
H for removing stray electrons.
The electrode
izing potentials applied thereto over leads 2| and
22 which potentials may be of substantially the
same value although lower than the positive po
tential applied to rods 4, 4 and anodes 6', 6'. The
beam up or down toward one of the rod-like elec
anodes 6’, 6’ are shown as being hollow or cup
trodes 4. The initial de?ection of the beam pro
shaped to minimize the e?ects of secondary emis
duced by the electrode 3 will then be increased
sion and to insure that secondary electrons do
by the action of the electric ?eld in the manner
not extend beyond the con?nes of the anode
described above, and the greatly increased de
structure. Of course, any other type of anode
?écted beam will impinge predominantly on that
structure, such as a plate, can be used instead.
one of the anodes 6 which is nearest the rod 4
The shield 'l' is somewhat different in form from
toward which the beam is moving. The elec
shield 1 of Fig. 1. Shield '7' is maintained at a
trodes 4, ‘4 are, of course, of such length and the 20 positive potential relative to the cathode, and is
potentials applied are of such value that the
composed of a central plate part M for enabling
electrons do not impinge on these electrodes but
axially traveling electrons to impinge thereon,
pass over the ends to be collected by anodes 6, 6.
and upper and lower apertures 20 for enabling
At extremely high frequencies there may be'sev
the de?ected electrons to pass-through the shield
eral waveswithin the cylinder 5' at any instant of 25 and to impinge on the anodes. The operation of
time. These waves start with small amplitudes
the system of Fig. 4 insofar as theipresent-invem
near the control electrode 3 and then grow to be
tion is concerned is substantially identical with
much larger waves before the output end of the
that of Fig, l. .
.
cylinder is reached.
Although rod-like electrodes 4, 4 of Figs l'to 5
As an illustration of the increase in de?ection
have been shown as beingparallel to each other
of the beam obtainable by the tube of the inven
and perfectly straight, they can be arranged at
tion, given by way of example only for purposes
a diverging angle and,‘if desired, curved slightly
of exposition and not by way of limitation, if the
outward from the axis of the device to correspond
control electrode potential on 3 can produce 0.01
to the shape of the path of the beam.
'
centimeter initial de?ection then the electric ?eld 35
Fig. 6 shows a cathode ray tube in accordance
traversed by the beam might increase this de?ec
with another embodiment of the invention,
tion to say 0.1 centimeter or more. Therefore,
which functionsby means of a magnetic ?eld,
the corresponding gain in ampli?cation maybe,
instead of the electrostatic ?elds of Figs. 1 to 4.
say 10 to 1 in current or 100 to 1 in power, or
In Fig. 6,. there is provided a ?eld coil 23 which
more. This increase in ampli?cation is effective 40 replaces the cylinder,.plates and rod-like elec
substantially independently of the frequency of
the currents to be ampli?ed.
'
' trodes of the other ‘?gures.
‘
The separate connections l5, l5 to the rod-like
electrodes and the potentiometer arrangement H
enables the direct current or low frequency po
tentials derived from the anodes 6, 6 to control
the average or direct current potentials on the
rods 4, 4 in a direction to keep the mean position
of the center of the electron beam properly cen
tered. As an illustration, assuming that one 50
anode 6 .tends to take more direct current than
the other anode,‘ then there-will be a greater‘
current ?ow and IR drop in one-half of the po
tentiometer H and a corresponding lowering of
the positive potential applied’ to that rod 4 di 55
rectly associated with the anode drawing the
greater direct current. The frequency response
of this beam centering arrangement is such that
it does not affect de?ections of the beam at ‘the
operating frequency but only prevents deflections 60
at lower frequencies and steady state. de?ections.
If desired, the cylinder 5 may be ?attened to
Coil: 23 is energized
by a source of unidirectional potential 24 and
provides a desired non-uniform spreading or
fan-shaped cross-section of the magnetic ?eld
throughout the space traversed .byv the, beam,
roughly in the manner indicated byrthe light
solid ‘lines labeled A. The magnetic ?eld in
tensity is greatest at or near the origin of the
beam.
,
.
_
In the arrangement of Rig. '6, electrons from
an indirectly heated cathode .2 are drawn'rto a
more positively charged screen H. A portion'of
the electrons, passing through a. hole in. the
screen l7, provide an electron beam which in
the absence of disturbing (i. e., de?ecting) forces‘,
travels in a straight line B to impinge upon the
approximate center of screen electrode 1’. In
following this undisturbed path, electrons travel
parallel to the magnetic ?eld along" the path and
the presence of the ?eld tends to prevent elec-'
trons straying from this path in accordance with
the well recognized phenomenon of magnetic
?eld focussing or restriction of the path of elec
take the approximate form of an ellipse in the
manner shown in Fig. 3, without departing from
tron beams in cathode ray tubes.
' '
'
the principles of the invention. It will be noted 65
Supposenow that; a high frequency potential
that‘the ?eld distribution of Fig. ‘3 is substan
is applied to an electrode 3, position-ed beside
tially the same as that of Fig. 2.
the electron beam, near its source. As av result
As; a practical matter, the cylinder of ‘Fig. 1
of the alternating current potential, electrons
and the ellipse of- Fig. 3 can be dispensed with
are given components of velocity, and energy, ‘in
and two ?at plates I8, l8 substituted therefor. 70 directions at right angles to the undisturbed di
Qne such arrangement, given by way of example,
is shown in Fig. 4. The ?eld distribution be
tween rod-like electrodes 4, 4 and the plates is
shown in Fig. 5 which represents a cross-section
of the tube of Fig. 4 along the line 5—5. I It.‘- Will
rection of ?ow of electrons. ’ Asa result of these
components of velocity,the electrons no longer
follow a nearly central straight path but acquire
a spiral motion due to moving out away from the
central‘ path and then’ being returned ‘to. the‘ cen
2,390,250
tral path again by the in?uence of the magnetic
?eld. The spiral paths of the de?ected electrons
are represented by dash-lines labeled C.
Suppose that, for magnetic ?eld values of the
strength existing in the region of electrode 3, the
electrons, as viewed endwise to the original un
3
surface of water in a long trough, this air would
give little if any energy to the water so long as
the water surface was perfectly smooth. How
ever, if we deliberately produced small Waves in
the water at the end of the trough from which
disturbed beam path follow a'path in circles of
the air comes, the presence of the waves would
provide a coupling between water and air which
diameter as shown at I in Fig. 7. If the mag
would cause the waves to grow in amplitude as
netic ?eld were uniform, the path of electrons,
they traveled down the trough. In this water
as viewed thus, would remain in circles as the 10 wave case We have another example of means
electrons moved all the way to the screen 1'.
to cause waves deliberately produced to grow in
However, if the magnetic ?eld strength decreases
strength with passage of time and distance but,
between screens H and ‘I’, as illustrated in Fig.
at all times, the waves are controllable by the
input wave power.
6, then the diameter of the circles formed by
projection of the path will increase as the elec 15
It should be understood that the invention is
‘trons move into the weaker magnetic ?eld. This
not limited to the precise arrangements of parts
7, is in accordance withwelLknown physical phe-.
shown and described since various modi?cations
nomena in which electrons moving at uniform
may be made without departing from the spirit
velocity and energy, at right angles to a mag
and scope of the invention. For example, the
netic ?eld, move in circles whose diameters are 20 cylinder 5 of Fig.1 or the ellipse of Fig. 3 can
inversely proportional to the intensity of the
be dispensed with and at least a large part of
magnetic ?eld.
the envelope made of metal, or the inner surface
By giving electrons components of velocity
of the glass envelope can be coated with metal
both parallel to and at right angles to a mag
to simulate the metallic cylinder or ellipse.
netic ?eld, we force them to follow a spiral path 25 What is claimed is:
in which the diameter of the spiral is inversely
1. The method of in?uencing a stream of elec
proportional to the intensity of the magnetic
trically charged particles which comprises sur
?eld.
rounding the stream over substantially its entire
In the arrangement of Fig. 6, rather small di
path of travel with a magnetic ?eld the axis or
ameter spiral motions, given to the electron 80 center of which is parallel to the direction of
paths by the alternating current potential on
principal motion of the stream, but which ?eld is
electrode 3, in the most intense part of the mag
more intense at and near the beginning of the
netic ?eld, grow to large diameter spiral motions
path of travel of the stream than at other por
as the electrons move toward screen electrode
tions of said path, and de?ecting said stream
1', into a weaker magnetic ?eld. Thus, a rela 35 near the beginning of its travel, whereby said
tively small amplitude, of electron stream wave
?eld produces a constantly increased de?ection
motion at one end of the electron stream path
as the stream progresses from its point of initial
will grow to a large amplitude of wave motion at
de?ection.
the other end of the path.
2. The method of in?uencing a stream of elec
This growing wave motion may be utilized to 40 trically charged particles which comprises sur
control and increase the control of the distri
rounding the stream of the major portion of its
bution of electron current between screen elec
travel with a magnetic ?eld, the axis or center
trode 1' and anodes 6', 6'. In the circuit arrange
of which is parallel to the direction of principal
ment shown. currents ?ow alternately to one or
the other of electrodes 6' at a frequency corre
sponding to the frequency of the input potential
applied to electrode 3. Thus, the arrangement
functions as a relatively high gain beam de?ec
tion type ampli?er.
The arrangement of Fig. 6 may be used as a 50
motion of the stream but which becomes pro
gressively weaker as the stream moves further
away from its origin, and de?ecting said stream
near its origin, whereby said ?eld produces a
constantly increased de?ection as the stream
moves further away from its point of initial de
?ection.
'
frequency doubler. by connecting a tuned output
3. In an electrical discharge device having a
circuit between screen electrode 1’ and paralleled
anodes B’, 6'. It may also be used as a detector
by connecting a suitable frequency selective de
tector output circuit between screen electrode 7'
cathode for producing an electron beam along
the axis of said device, a pair of anodes sym
metrically arranged on opposite sides of said
axis, a de?ecting electrode adjacent said beam
and located between said cathode and said
anodes, and means for producing a magnetic ?eld
and paralleled anodes 6', G’. In fact, all of the
functions possible with other electron beam de
?ection vacuum tubes may be performed with the
improved tube of the invention.
whose axis is parallel to the direction of prin- '
cipal motion of said beam and is effective over
I prefer to call the circuit of my invention a 60 the major portion of the travel of the beam but
which becomes progressively weaker as the beam
“growing wave ampli?er” because the control po
moves further away from said deflecting elec
tentials on electrode 3 cause the electron stream
trode.
to de?ect in such a way as to produce a wave in
4. In an electrical discharge device having a
the stream which travels along the length of the
65 cathode for producing an electron beam along the
tube with a velocity equal to the velocity of elec
axis of said device, a pair of anodes symmerti
trons in the stream. This wave starts with small
cally arranged on opposite sides of said axis, a
amplitude near the de?ecting electrode and grows
de?ecting electrode adjacent said beam and lo—
to be a very much larger wave before the output
cated between said cathode and said anode, a
end of the tube is reached.
70 magnetic ?eld coil surrounding said beam and
There is a crude analogy between the e?ect
being effective over substantially the entire path
of the electric ?eld in the cylinder increasing the
of travel of said beam on both sides of said de
wave amplitude and an effect which might be
?ecting electrode, and a source of direct current
produced with surface waves on water. If we
energizing said coil, said coil being so arranged
passed a strong current of air parallel to the
that the axis ,or center of its ?eld is parallel to
2,390,250
the direction of principal motion of said beam.
; 5. In an electrical discharge device having a
cathode at one end thereof for producing an elec
tron beam along the axis of said device, and an
anode near the other end of said device, said
anode being located to one side of said axis,‘ a
de?ecting electrode adjacent said beam and lo
cated between said cathode and said anode, and
means for producing a magnetic ?eld having an
ranged on opposite sides of the -,_;longitudinal axis
of said discharge device, ‘a positively charged
screen having an aperture registering with said
axis located adjacent said cathode, a de?ecting
electrode located adjacent said screen 'on the
side thereof opposite the cathodeland also-being
adjacent said beam, another screen electrode 1o~
cated adjacent said anodes and positioned be~
tween said anodes and said ‘cathode, said. last
axis or center which is parallel to the direction 10 screen having electron permeable surfaces rad
jacent both of said anodes, and means for pro
of principal motion of said beam and is effective
ducing a magnetic ?eld havingan axis or center
over substantially the entire distance between
which is parallel to the direction of principal
said cathode and anode but which becomes pro
motion of said vbeam and is, effective over the
gressively weaker as the beam moves further
15 entire distance between said c‘athodeandlsaid
away from said de?ecting electrode.
anodes but which is relatively-strong. near said
6. In an electrical discharge device having an
?rst screen and relatively weakvnear said: other
indirectly heated cathode at one end thereof for
producing an electron ‘beam, a pair of anodes at
, CLARENCE W.
the'other end of saiddevice symmetrically ar
screen.
»
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