close

Вход

Забыли?

вход по аккаунту

?

Патент USA US2107519

код для вставки
Feb. 8, 1938.
|_ SHQENBERG E1- AL
2,107,519
ELECTRON DISCHARGE DEVICE
Original Filed July 27,' 1934
3 Sheets-Sheet 1
Lwz wanna
(‘,4 397 4641011 411 ll
Smiy HIM!’
"up To 15
n'rmn- In Ill/(Air
Feb- 8, 1938.
‘I. .SHOENBERG ET AL
2,107,519
ELECTRON DISCHARGE DEVICE
Originjal Filed July 27, 1934
S Sheets-Sheet 2
[5414; 610618513
.
a .17.
(4M1 sun" "4‘
, W‘! "W"
A Trauij/ 714’ MM KM”
Febjs, 1938.
|. SHOENBERG ET AL
2,107,519
ELECTRON DISCHARGE DEVICE
Original Filed July 27, 1934
3 Sheets-Shed 3
Amy's] ne MIL/“W5
Patented Feb.v 8, 1938
2,107,519
, UNITED STATES"
_
PATENT OFFICE ~
2,101,519
ELECTRON DISCHARGE nnvrcn
Isaac Shoenbcrg, London, Cabot Seaton Bull,
Hillingdon, and Sidney
En?eld, Eng
d, minors to Elect Rodda,
and Musical Indus
tries Limited, Middlcsex,ricEngland,
a'company
of Great Brltain
Original application July 27, 1934,
Serial No.
737,192. Divided and this application
June 1,
1935, Serial No. 24,482. Renewed June 12, 1937.
In Great BritainAugust 2,
1933
23
The present invention relates to electron dis
charge devices of the
10
I
(Cl. 250-275)
course of its oscillation, the anode voltage falls ,
_ more than a
certain small amount below the
?xed voltage of the screening electrode.
For
many purposes the ?ow of such secondary emis
sion current from the anode to the screen is un
' desirable and proposals have been made to pre- '
'vent it.
20
v25
According to the present invention a discharge
In one known arrangement a third grid, us
device comprises a cathode surrounded by a con—
ually connected to the cathode, is arranged be
tween the screening electrode and the anode.
being surrounded in part by an anode and in
trol grid and a screening grid, the screening grid
It is the principal object of the present inven
tion to provide an electron discharge device of
the kind above referred to in which the ?ow of
secondary emission current from the anode to the
screening electrode can be prevented with the
20
the auxiliary electrode.
Various forms of discharge devices which can
be made to exhibit the feature of the present
invention will be described hereinafter and the
theory which is at present considered to explain
the observed phenomena will be set forth. It is
to be understood, however, that this theory may
require modi?cation in the light of further
knowledge.
'
30
The invention will be described with reference
' to the accompanying drawings, in which
35,
Figures 1, 6 and 7_are diagrammatic views in
plan of certain forms of discharge devices accord
ing to the present invention, I
Figures 2 to 5 are curve diagrams serving to
explain certain characteristics of discharge de
vices according to the invention,
40
' Figures 8, 9 and 12 are diagrammatic views in
a normal operating potential the anode voltage
anode current characteristic exhibits no in?ex
ion. The space charge itself
45 electrostatic ?eld ‘
plan of further forms of devices according to the 40
invention,
Figures 10 and 11 are diagrammatic views in
elevation and plan, respectively, of a further form
of the invention,
Figures 13, 14, 15 and 16 are views in side ele 45
vation, front elevation, sectional elevation and
plan, respectively, ofv a preferred constructional
embodiment of the invention,
Figure 17 is a perspective view of an anode of
50
may be insu?icient.
the device of Figures 13 to 16,
Figures 18 and 19 are perspective views show
Although in some forms of discharge devices,
according to the present invention the distortion ing methods of supporting anodes in arrange
ments according to the ‘present invention, and
of the electrostatic ?eld produced by the auxil
Figures 20, 21, 22 and 23 are views in eleva
55
2,107,519
2
tion, sectional plan‘, sectional elevation‘and un-l
derside plan, respectively, oi a second preferred
constructional embodiment of the invention.
of a further drop in potential in the space.
Such a further drop can of course be produced
by space charge due to the primary electrons
Like parts are indicated in the various ?gures
:31
by the same references.
I
'
from the cathode and the secondary electrons
from the anode. It has been found however
that unless, in the absence of electron emission,
Referring to Figure 1, there is shown diagram
matically the electrede arrangement of one form
of device according to the present invention. A
cathode a is of rectangular cross-section and is
elongated (in a direction perpendicular to the
10
paper). Two control grids b1 and be are ar
the value of
ranged one on each side of the cathode 'a and are
_
111..
dz’
10
is\ positive to a substantial degree, the space
charge is incapable of forming the potential min
imum at least in those cases which have so far
spaced therefrom by means of insulating strips been investigated, with normal working currents.
In Figure 2 there is shown in dotted lines the
10, one strip being arranged near one end of the
cathode and another near the opposite end. distribution of potential g1 when the screen in
15 Thus the strips k are located substantialiy out; dicated by C1 is closer to the anode. it will be
side the electron stream. Two screening grids seen that the potential gradient close to the
c1 and c: are arranged outside the control grid anode is much higher than in the case above
and consequently a greater additional 20
and‘are spaced therefrom by means of further ’ considered
drop
in
potential
will be required to produce the
insulators k. This assemhly may be clamped to
20
desired potential minimum. This curve indi
gether in any convenient way and mounted with
cates the importance of arranging the anode at
in a casing e which constitutes an auxiliary elec
a su?icient distance from the screen taking into
trode. This auxiliary electrode has portions 1 ex
tending towards but not to any great extent into account the voltages and currents at which the
electrodes are to work.
»
25 the discharge space. Anodes d1 and (12 are pro
Figure 4 shows the distribution of potential
vided as shown. It will be assumed for the pres
ent that the anodes d1 and
are electrically‘ when the anode and screen are at the same po
connected together and that the two grids bl I tential. Here also
and b: on the~one hand and c1 and 02 on the
30 other hand are also connected together.
If the anodes d1, dz be maintained at a
positive 'potential relatively to the cathode a and
_
if the screens 01 and c: be maintained at a po
tentiai which is higher than the anode, the ‘po
tential distribution in the space between each
anode section d1 and (Z2 and the corresponding
screen section or or 02 along lines-normal to the
30
_
is positive
and therefore a potential minimum is
produced even in the absence of electron flow.
This minimum, produced electro-staticaliy
when the anode voltage is equal to that of the
screen, if it be of su?icient depth, prevents the
flow of secondary electrons between the anode
and screen in both directions under conditions
screen and anode will be somewhat as repre
sented in Figure 2, where voltages are plotted as
ordinates
against distances as abscissa. The
40
in which the depression due to space charge
alone, owing to high electron velocities, is insu?i
cient. When the anode voltage is much lower
position of the anode is represented by the line
D and the position of the screen by the line C,
the heights of these lines representing the po
tentials at the anode and screen respectively.
than that of the screen, the increase in space
charge effects due to reduction in eiectron veloci
ties ‘causes such an increase in the depression in
potential that although there is now no electro
45 The dotted curve go shows the distribution of
static potential minimum, there is su?icient total
depression of the potential below that of the
anode to prevent the flow of secondary electrons
potential along lines between the anode ‘and
screen approximately normal to these electrodes
-
in the absence of eiectron flow and without the - from the anode to the screen.
auxiliary electrodes. In the case of in?nite plane
Along a line in a direction at right angles to .
50 parallel anode and screen this curve 90 is a
straight line. In other cases it is curved some
what as shown. Owing to the action of the aux
the direction 'of the electron stream '(that is
parallel to the anode surfaces) the distri iition of
potential in the space between the anode and the
iliary electrode including theportions 1 thereof,
screen will of course be such that there is a
it will be seen that the distribution of potential
55 between the anode and screen represented by
the curve 9 is such that
(I:2
is
made
more
positive
proceeding
from the anode
60
to the screen, where V is the potential at any
point and a: is the distance of this point from'the
anode. That is to say the rate oEI change of the
maximum about midway along the line and low 55
values at the two ends. The potential distribu
tion in the space is thus in the form of a saddle'
The modi?cation of the potential distribution
in the anode-screen space produced by the aux»
iliary electrode has afocusing or concentrating 60
e?ect upon the electron stream in the screen to
anode space. The result of this concentration
of the electrons is that the space charge developed
is considerably increased and the formation of a
potential gradient is more positive, the poten-. potential minimum by space charge is assisted.
65
tial gradient being of course
:2, .
dz
It will be ‘seen also that the potential gradient in
the neighbourhood of the anode .is very small
and for this reason very little further drop in po
tential in the anode-screen space is necessary to
produce a potential minimum in the space as
shown‘ in Figure 3 where the curve 9 of Figure 2
is shown'dotted and the curve It shows the effect
Thus if secondary electrons are emitted by the
anode at a velocity of about 20 volts, for example,
they may travel some distance towards the
screening grid until they, reach a position in
which, if the space charge is suii'iciently dense, 70
they are brought to rest by the potentials aris
ing from the space charge and the electrostatic
?eld. They then return to the anode and give
rise to more secondaries. The process may be
repeated so that it may be expected that in the 75
2,107,519
neighbourhood of the anode surface there will be
~ '
v3
potential. Under these conditions the electrons
projected towards the anode will come to rest
vbefore reaching the anode on account of the elec—
trostatic ?eld, the low anode potential and the
in the neighbourhood of the anode produced by
modi?cation of the electrostatic ?eld will be ac
centuated by the space charge due to the primary
electrons and also by the space charge due to the
secondary electrons, and the electrostatic and
space charge modi?cations are arranged together
portion ?owing ‘to
anode potential increases.
For most purposes a tetrode is required to
Above the knee voltage there is still a potential
minimum along the electron path but this mini
have an anode voltage~anode current charac
teristic of the kind shown in Figure 5 wherein the
anode voltage EA is shown plotted against anode
current In for various values of the control grid
voltage Eg- It is usually desirable that the knee
' m should be as sharp as possible and should oc-.
cur at as low a voltage as possible, and that there
should be no.in?exion or kink, or at least no
marked in?exion, in the characteristic. A kink
zero potential, substantially simultaneously over
the whole area of the virtual cathode. If the size
such as appears at n in the curve Eg=—4 and
to a less extent in the curve Ey=--3 is not mate
rial because it is‘at a point away from any prac
tical working point. However, it has been found
possible to produce devices according to this in
vention in which no noticeable kink is present in
A practical load line for a
resistive load is shown at o and in the case of an
inductive load the load line may have the form
shown dotted at 01. In neither case do apprecia
bly in?ected portions fall within the working
range of anode voltages and currents. It will be
assumed that the type of characteristic shown
in Figure 5 is desired (although it will be under
stood that for certain purposes other forms of
characteristic may be preferred) and certain
ways in which departures from the desired char
acteristic are obtained will be explained in order.
that the eifects of the several variables may be
appreciated. '
If either the anode d1, d: is too small in area,
the auxiliary electrodes e are too close to the
electron stream or the projections or slats Z ex
tend too far into the electron stream, the char
acteristic has a knee m of'large radius of curva
ture and the value of anode voltage above which
- the current is nearly constant is not well de?ned
voltage around the edges of the beam than in the
centre, thus giving rise to a knee of lai'ger radius
of curvature.
If the anode be unduly large, the secondary
space charge consisting of electrons moving slow‘
ly in random directions can diffuse to the por- _ I
tions of the anode not struck by primary elec
trons or at least not struck by any considerable
number of primary electrons. The space
charge is in this case reduced in intensity and
may be insu?icient to prevent the ?ow of second
ary electrons to the screening grid. Even if the
anode is not unduly large it is usually necessary
to take steps to prevent the secondary electrons
from diifusing around to the back of the anode
with similar results to those produced by an un
duly large anode. For this purpose the auxiliary
electrodes already described are arranged to ex
tend to points close to the edges of the anode.
With anodes'of small size it may be found un
necessary to extend the auxiliary electrodes so
.close to the anode.
Unless the anode is of‘ considerably' greater
length
and rather high. If the area of the anode is in—.
creased or if the auxiliary electrodes are ar
ranged i'urther away from the electron stream,
thedesired form of characteristic can be obtained.
Further increase in area of the anode or in the
distance of the auxiliary electrodes from the
electron stream gives rise to a characteristic in
which the knee m is very sharp and the anode
current falls beyond the knee and then rises again
' so that the curve exhibits an. in?exion.
This
form of characteristic indicates that secondary
emission is reaching the screening grid.
I
The way in which the device with what has been
referred to as the desired characteristic is be
lieved to operate will now be described.
The screening grid will be assumed to be held
at some suitable positive potential relative to the
cathode, the auxiliary electrode will be assumed
to be at cathode potential and the anode voltage
will be regarded in the ?rst place as at cathode
‘ the anode only.
If it is required that the knee voltage should
be reduced, it is necessary to reduce the primary _
space charge so that the virtual cathode formed
thereby may collapse at a lower anode voltage.
This can be. done by increasing the screening
grid voltage or by reducing the distance between
the anode and the screening grid. The limit to
which these two changes can be taken depends,
in the case of the former, upon the ability of the
primary space charge, with the assistance of the '
secondary space charge and the electrostatic ?eld,
to maintain a su?iciently pronounced potential
minimum to prevent the secondary electrons
from travelling to the screening grid and, in the 75
2,107,519
4
shown in Figure 6. The electrostatic field in the
space between the'anode and screening grid is
not affected by this shortening of the auxiliary
latter case, upon the fineness of structure of the
screening grid.
It has been found that if the distance between
the anode and the screening grid be too small
in comparison with the pitch of the screening
grid, for example about four times or less, the
electron distribution over the surface of the
anode is markedly non-uniform. The effect of
this is that secondary electrons can return to
electrodes. Auxiliary electrodes 11, preferably
electrically connected to the screening grids 0i
and ca, may then be provided around the grids and
cathode. In the construction shown in Figure ,6,
the auxiliary electrode is extended around the
i
back of theanode as shown at q.
the screening grid through those parts of the
A modi?cation of the arrangement of Figure 1 10
is shown inpFigure 7 where the projections l are
wires because in these parts there is very little
omitted and the auxiliary electrode ‘e is shaped
so as to in?uence the electrostatic ?eld in the
anode-screen space in the desired manner. As in
10 space which lie in front of the screening grid
primary space charge and consequently only a
small screening effect due to space charge.
This effect of the non-uniformity of‘the elec
15
tron stream can be reduced or removed‘ by divid
ing the anode into a plurality of parts and pref
erably by inserting auxiliary electrode plates,
which may be connected to the auxiliary elec
Figure 6, the auxiliary electrode is continued be
' ?anges 1' which can be bolted or otherwise ?xed
20 trodes already described, between the two or more
parts of the anode. v
I
together, suitable insulating means In being pro
20
vided between the electrode 6 and the grids c1
.
Sov far as it has been assumed that the aux
iliary electrodes by which the electrostatic po
tential minimum are produced'were maintained
at a ?xed potential equal to that of the ‘cathode.
This is not necessarily the case. In the ?rst
place it may be found desirable or convenient to
and 02.
Another construction according to the inven
tion is shown diagrammatically in Figure 8. In
Figure 8; the elongated cathode a is surrounded
by a control grid b which is in turn surrounded
by a screening grid 0. Around the screening grid
arrange the auxiliary electrodes at ?xed poten
tials di?ering from the cathode potential. An
auxiliary electrode at cathode potential in av
given position can often be replaced, with equiv
c is arranged an anode in two sections (11 and dz
alent results, by'an auxiliary electrode located
closer to the electron stream and having a poten
tial above that of the cathode or by an auxiliary
electrode located further from the electron
stream and having a potential lower than that
of the cathode.
15
hind the anode at q and it also acts as a clamp
for the grid and cathode assembly. For this pur- '
pose the electrode e is formed in two halves with
'
Further‘ it is not necessary that the auxiliary
electrode potential should be. maintained con
40 stant. In some cases the auxiliary electrode po
tential may be allowed to vary with the potential
of the anode or control grid.
In addition to the feature of this invention,
namely the provision of means whereby an elec
trostatic potential minimum can be developed at
each of part cylindrical shape and between the
anode sections (ii and (12 are arranged further 30
part cylindrical electrodes e1 and e: constituting
sections of the auxiliary electrode. The two grids
b and c are of cylindrical shape and these two
electrodes together wi the‘ anode and auxiliary
electrode preferably extend over substantially
the whole length of the cathode a. In this case
it will be seen that the sections _81 and. e2 of the
auxiliary electrode constitute continuations of
the anode sections di and (l2 and lie in the same
cylindrical surface as the anode sections, this
surface being coaxial with the cathode a and the
two grids b and c. The sections of the auxiliary
electrode are connected electrically together and
are either connected to the cathode, for example
within the envelope 1‘ of the device, or else they
are brought out to a suitable external terminal
some region in the space between the screening by which-they can be maintained at a low poten
when these two elec- '
grid and the anode, at least
tial usually not di?ering greatly from cathode
trodes are at the same potential, it is usually de
potential.
.
sirable to arrange that
The auxiliary electrodes ‘e1 and ez serve to 50
(1) A region between the screening grid and modify the electrostatic ?eld in the anode-screen
anode which constitutes a virtual cathode at low space in such a way that
anode potential should become a region of min
imum potential, exceeding zero potential, sub1- ~
stantially simultaneously over the greater part of
the region as the anode potential is increased, _ is su?iciently positive proceeding from the anode
to the screen and when electron current is ?ow
and
(2)The distance between the anode and the ing between the cathode and the anode a space
‘ screening grid should not be‘ less than about twice
the pitch of the screening grid, that is to say the
mesh of this grid or the equivalent structure size.
Condition (1) is not essential since if it is not
ful?lled the principal effect is to in?uence the
shape of the knee of the characteristic. The
e?ect of this may only be that the ampli?cation
65 obtainable‘ is not so free from distortion as with
a sharper knee. ‘A knee which is slightly more
rounded than it need be may be advantageous
in some cases as it has been found possible to
7,0
obtain a higher impedance above the knee volt
age under these conditions.
Instead of allowing the auxiliary electrodes e
to extend alongside of the grids and cathode as
shown in Figure 1, the auxiliary electrodes may .
be terminated just short of ‘the screening grid,
for example at the inwardly projecting ‘slats l as
75
charge is set up in the space as already de
scribed. In the regions of the space opposite the 60
rods s which support the grids,.however, an elec
tron shadow is cast and in these regions what
may be termed the “electron screen” which serves
to stop secondary electrons is absent or insuf
?ciently dense. To overcome this difficulty there
are provided shield members t which are so
placed that they stop secondary electrons which
might otherwise reach the screening grid 0.
The shields t may be of metal or of insulating
material. In the former case they may be of solid 70
metal or in the form of a metal ‘coating on an
insulating backing. The metal surface may be
connected to the auxiliary electrodes e1 and e2
or to some other point of relatively low potential
or they maybe left unconnected. In the case 75
2,107,519
'
5
where insulating shields are used they may be of ?xed to the anode d, for example with the aid of
glass or mica for example and in operation each rivets, near to the top and bottom thereof. These
to that of the cathode.
'
_
_
placed in position upon tongues v1, 122, v: and ‘D4 5
In a modi?cation of the arrangement of Figure
8 shown in Figure 9, the anode and auxiliary elec-
bent outward from the plane of the auxiliary
electrodes as above described and these tongues
_ trode are still further subdivided into parts d1,
(Z2, (Z3 etc. and 81, ea, ea respectively the former
are bent over the projecting ends of the strips as
shown at or and 112 to hold them in position.
10 parts being interspersed with the latter.
Instead of bending tongues out from the body 10
cathode. Thus each anode section a1, a2 and
15 each section of the auxiliary electrode e1, e2, e; is
in the form of a short cylinder.
also be applied to the securing of a plurality of
anode elements to one another in cases, such as 15
have been described above, in which the anode
Figure 12 illustrates a modi?cation of the arrangement of Figure 8 in which the shields t
and the auxiliary electrodes e1, e: are combined
20 as
andthe
theauxiliary
whole electrode
e1, 62, t may be regarded
electrode.
»
is divided into a plurality of parts. When-the
anode elements are separated by an auxiliary
electrode the adjacent sections of the auxiliary
electrode can also be supported' Irom'one’ another 20
In the arrangements of Figures 1, 6, 8, 9 and
10, the auxiliary electrodes are themselves or
'have parts it (Figures 1 and 6) which form con25 tinuations of the anode.
a similar way any one electrode can be supported
from any other electrode so long as these elec
trodes have parts extending su?iciently near
to 25
gether.
-
In Figure 12 the auxiliary electrode although
not constituting a continuation of the anode surface nevertheless has edgeslocated close to edges
of the anode so that the anode sections d1 and d2
30 together‘with the auxiliary electrodes form sub-
tially square or circular shape. When these elec_ trodes have a much greater length (in the direc-
40 tion of the length of the cathode) than breadth,
In discharge devices of the kind described in
Referring now to the constructional embodi
ment of the invention shown in Figures 13 to 17,
two control grids b1 and b2 and two screening
grids c1 and c: are mounted in suitably spaced re
lation from one another and from the cathode a by 30
of mica. Two anodes 111 and dz are ?xed to the
mica strips 2 by means of tongues 3 which pro
ject through the mica, and are bent over.v As- .40
projecting portions 6 extending close to the edges
45 which the auxiliary electrodes extendclose to the
of the anode. In the rectangular apertures in 45
50 in which this may be done are‘illustrated in Fig-
of the auxiliary electrodes are caused to bear 50
55 the top of the two auxiliary electrodes. Two
the cathode and grid assembly is thus held ?rmly 55
60 plate, has a rod 20 preferably of square section‘ ed so that together ‘with the screening grid 0 60
65 ends. The rod 10 which projects from the upper
70 engaging in the notches in the‘ends ofthe msw
to holdthem in position,
In a, modi?ed construction shown, in Figure .19
75 thin strips of insulating material 21 and z: are
may be connectedto the cathode within the en- 70
at any desired low potential. The potential of the
auxiliary electrode is usually ?xed but 88 al—
ready stated need not necessarily be so as it may 75
2,107,513;
produced by‘ the use of a screen which is too
i
be caused to" vary with the anode potential for
example.
.
'
Referring to Figures 20-23, there is shown a
constructional embodiment (if the type of device
. ?'The electrodes are mounted
between twio discs e'f insulating material Si and
Ill for example of 'mica which have‘ serrated
edgies adapted to bear against the inner walls of
the envelope f. ‘The anodes
v1o auxiliary electrodes of and e: arev mounted-npon
the mica dies 9 and III with the aid of lugs II
which pass through holesjin the discs and are
open.
_
We claim:
.
_
r
1
1?
-
1. An electron ?discharge device comprising,
within an evacuated envelope, a cathode sur C1
rounded by a control grid, a screeninggrid sur
- rounding said control grid, an anode having sur
faces coextensive with‘and disposed oppgisite to
longitudinal portions of said screening gricFand an.
auxiliary, electrode insulated frem said anode
10
and having surfaces coextensive with and dis
posed opposite to other ilongitudinal portions of
said screening girji'd, said anode and said auxiliary
bent over. Thus the electrodes (11,42, e1, ez serve electrode being 'jeach' in a plurality of sections,
to’ form a'rigid structure with the discs 9 and I0. I the sections of said anode being interspersed with
15 The cathode a is lecated in apertures in the cen ,the sections of said auxiliary electrode.
2. An electron discharge device comprising an
tres of the discs 9 and Ill and the grid supporting
reds s also pass ;through holes in the discs 9,v elongated cathode surrounded by a control grid,
aiid I0. The cathode is of the indirectly heated . ' a screening grid surrounding said control grid, an
type and the heater is brought out through leads " anode having surfacesgcoextensive withrand dis
20 I2 and I3, the cathode itself being connected to
‘lead I‘. The anode parts di and (12 are con
posed opposite to longitudinal portions of said
screening gridfand an auxiliary electrode insulat
nected together by a wife l5 and to a lead l6.f ed from said féanode and having'surfaces coex
tensive with and disposed opposite to other lon
The auxiliary electrode partsei. and e: are con
nected together and to shields t by a wire l1 and
gitudinal portions of said screening grid, said
anode and said auxiliary electrode being each in
"b and c 'e-re connected respectively to leads ,l9 and: a plurality of sections, the sections of said anode
7'20. The shields t are provided ‘in the shadow being interspersed with the sections of said auxil
"cast by the rods .9, for the purpose described in iary electrode, and each of said sections extend
connection with Figure 8. These shields are ing over substantially the whole length. of said
30 ?xed to the mica'discs 9 andjill with the aid cathode.
i
I
7
,
25 to a lead l8 and also to the cathode a. ' The gridsE
of lugs 2|.
,.
3.. An electron discharge device comprising,
f
The anode @ctions a’; and 112 may be provided
within an evacuated envelope, a cathode sur
of small part annular members of sheet material.
35 Theseislats are preferably arranged fairly nee;
rounding said control grid, an anode’ having sur
as shown with' slats or projections 22 in the form , rounded by a control grid, a screening grid sur
faces coextensive with and disposed opposite to
other longitudinal portions of said screening grid
i to the upper and lower end of, each ,section 51'
and an auxiliary electrodeiinsulated from said
anode and having surfaces icoextensive with and 40
disposed opposite to other longitudinal portions
of said screening grid, said anode and said auxil
iary electrede being each in a plurality of sec
tierfns, the sections of said anode being inter
spersed with the sections of said auxiliary? elec
trode and each of said sections being of part cy 45
and‘ 112. In one example they aredis'tant from
the ends of the sections (21 and (12 by about one
fifth the whole length of the sections. The pur
40 pose of these slats is :to intercept electrons trav
elling obliqueiy in the anode-screen space which
might in the absence of the slats reach the
screen around the outside of the space charge
area.
Iti'éhas
'
‘
'
found that in addition :to the vari
_ lindrical shape and being disposed ‘so-axially with
7
ous factors influencing the behavior of discharge respect to said ‘cathode.
4. An electron discharge device comprising,
devices according to this invention aiready men
tioned, there are certain other points which within an evacuated envelope, a cathode sur 50
should be taken 5 to consideration. If the rounded joy a coritrol grid, a screening grid sur
roundingfjsaid control grid, an anode having sur"v
50 screening grid be ariranged too close to the con
trol grid or? be too’ open, the control, grid may faces coextensive with and disposed opposite to
iongitudinal portions of said screening g'i‘id and
produce a reduction in potential in the anode
an auxiliary electrode insulated irom said anode 55
scr'een spagie. )This reduction in potential en
hances the'effect of the auxiliary electrode and and having surfaces coextensive with and dis
55 must be taken into account when designing the posed opposite to otherjlongitu?nal portions of
said screening grid, saidianode and said auxiliary
device or eise firstly the knee of the characteris
tic may be of unduly large radius of curvature electrode being each in a plurality of sections, the
and secondly the impedance of the device above sections of said anode being interspersed with the 60
the knee voltage :inay be lowered. The former sections of said auxiliary electrode and each or“
6° effect is believed" to arise because the virtual ' said seetions being ofpart cylindrical shape and
cathode disappears at different voltages at The
dif- . being disposed in a single cylindrical surface co
axial with said cathode.
7
ferent paints in the anode-screen space,
‘5. An electron discharge device comprising,
‘latter effect is believed to arise from the influence
of the control grid in preventing the removal of within an evacuated 'lenvelope, a cathode sur
65 secondary space charge from the screen by the rounded by a control grid, a screening grid sur
rounding saidfcontrol grid, an anode having sur
anode.
g
‘In some constructions it is desirable to align
the apertures it? the control grid with the aper-’
tures iii the screen in the direction of the elec
tron stream and if a device is designed to oper-é‘
fate satisfactorily vin accordance with the present
invention with aligned grids it may be Qfound to
operate unsatisfactorily if the grids are not
75 aligned. The effect produced is equivalent to that ‘
faceslcoexteneive with and disposed opposite to
longitudinal portions of said screening grid, an
auxiliary electrode insulated from said anode
and having surfaces coextensive with and dis
posed opposite to other longitudinal portions of
said screening grid, said anode and said auxiliary
electrodebeing each in a piurality of sections,v
the sections of saidanode being interspersed with
2,107,510
‘ the sections of said auxiliary electrode, and insulating means connected between said anode
'
r
7
space between said anode and said screening grid
and conducting shield means for substantially
said auxiliary electrode sections.
6. An electron discharge device comprising,
said region.
. 12- An electron discharge device having, with
within an evacuated envelope, a cathode sur-
m an evacuated envelope arranged in the Order
rounding said control grid, an anode surrounding
10 a part of said screening grid and an auxiliary
electrode electrically connected to ~,aid cathode
within the envelope and surrounding another part
of said screening grid, said anode and said auxil5 tions, the sections of said anode being interspersed with the sections of said auxiliary electrode,
5
and an anode, said anode extending over a part
01’ the Space around Said cathode, wherein said 10
device also has Within Said envelope means which
form a region 01’ electron shadow in the space
between Sald anode and Said Screening grid and
to said cathode for substantially preventing the 15
Passage of secondary electrons from said anode
to said screening grid through said region.
30
tions having their edges disposed close to adjacent edges of said auxiliary electrode sections.
tolsaid Screening gri_d through said l‘egl'on- '
_ 14- An electron discharge device having, With
grid and an anode, Said anode having a plural-
of the space around said cathode, wherein said 35
node having an equal number of c1rcumferen_
space hetween said anode and said screening grid 40
allel to adjacent edges of said auxiliary electrode
connected electrically to said cathode'
seething
9. An electron discharge device having, with-
30
45
.15: An electron discharge device comprising,
Wlthm an evacuated @Qvelope, a cathode 5111'
grid and an anode, said anode extending over a
sald control grid and screening grid disposed sub- 50
said anode_
electrode being each in two sections, the sections
55
~
10. An electron discharge device having, with-
in an evacuated envelope arranged in the Order
60 named, a cathode’ a control grid’ a screening grid
0? §a1d auxlljar‘y electrode and §aid shield being
disposed to be intersected
Sald plane and the
sections Of said anode lying between the sections 60
wil U1
between said anode and said’ screening grid and ' anode including {1 plurality 01' Circumferential-11y 65
in an evacuated envelope arranged in the order
CPmDI‘iSiIIg 8-? electrode formed of a plurality of 70
said device also has within said envelope means
5 which form a region of electron shadow in the
1'7- An electron discharge device comprising a
cathode, #1 control grid Surrounding the Cathode, 75
2,107,519 I
8
a screen grid surrounding the control grid, an
anode including a plurality of circumierentially
spaced sections disposed around the screen grid,
and means whereby an electrostatic potential
electron discharge device a space charge between
said screening gridand anode, said control grid
and screening grid being provided with side rods
lying in a common plane, said side rods forming
a region of electron shadow in the space between
minimum is developed in a region in the space
between the screen-grid and anode,_said means
said anode and said screening grid, and shield
means for substantially preventing the passage
- comprising low potential electrodes arranged be
tween adjacent anode sections and outside the
of'secondary electrons from said anode to said
space discharge path between cathode and anode.
\ 18. An electron discharge
device comprising a‘
screening grid through said re‘gion.
~
22. An electron discharge device including an
'10 cathode, a control grid surrounding the cathode,
evacuated envelope having within the envelope
and arranged in the order named 'a cathode, a.
control grid, a screeninggrid and an anode, said 15
a screen grid surrounding the control grid, a plu
rality of circumferentially spaced members ar
ranged aboutthe cathode and coextensive there
15
‘screening grid and anode being spaced from each
with, alternate ones of said members being elec
trically connected together and constituting the
anode electrode, the remaining alternateemem
bers being electrically connected together and
constituting an auxiliary electrode.
,e
screening grid and anode being spaced from
,each‘other to provide during operation or said
during operation of the tube a
space charge between said anode and said cath
' other to ‘provide
1
19. An electron’ discharge device comprising a
20 cathode, a control grid surrounding the'cathode,
a screen grid surrounding the control grid, a plu
rality‘of circumferentially spaced members ar
ranged about the cathode and coextensive there
with, alternate ones of said members being elec
25 trically connected together and constituting the
ode, saidcontrol grid and screening grid having
side rods lying in a common plane, said side rods 20
-forming' a region of electron shadow in the space
between said anode and said screening grid, and.
a conducting shield means for substantially pre
venting passage of secondary electrons from said
anode to said screening grid through said region. 25
23. An electron discharge device having an
evacuated envelope containing in the order named
, anode electrode, the remaining alternate mem
a cathode, a control grid, a screening grid, and
bers beingelectrically connected together and to anode, said screening grid and anode being spaced 30
the cathode and constituting’ an auxiliary elec . to provide during operation of the device a space
charge between said screening grid and’ anode,
30
20. An electron discharge device as de?ned in said control grid and screening grid having side
trode;
'
,
.
claim 19 wherein there are provided means which , rods lying in a_ common plane, said side rods
forming a region of electron shadow in the space
form a region of electron shadow in the space be
tween the anode and the screen grid, and shield betweensaid anode and said screening grid, and 85
35 of secondary electrons from the anode to the
’means for substantially preventing the passage
conducting shield means electrically connected
to said cathode for substantially preventing pas
screen grid through said region, said shield means
, being electrically connected to both the cathode
sage of secondary electrons from said anode to
'said screening grid through said region. ,
and to‘ the auxiliary electrode.
21. An electron dischargedevice including an
40 evacuated envelope and having arranged in the ..
order named within-the envelope, a cathode, a
control grid, a screening grid, and an anode, said
' v
I. SHOENBERG.
*
SIDNEY RODDA.
c. s. iBULL.
510
Документ
Категория
Без категории
Просмотров
0
Размер файла
1 392 Кб
Теги
1/--страниц
Пожаловаться на содержимое документа