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Патент USA US3090900

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May 21, 1963
w. VEITH ETAL
3,090,890
COLOR TELEVISION TUBE HAVING VENETIAN BLIND-TYPE GRID
Filed July 7, 1960
Am
2 Sheets-Sheet 1
May 21, 1963
w. VEITH ETAL
3,090,890
COLOR TELEVISION TUBE HAVING VENETIAN BLIND-TYPE GRID__
Filed July 7, 1960
2 Sheets-Sheet 2
Fig.2
ice
3,090,890
Patented May 21, 1963
2
screen electrode according to the respectively appropriate
color strips of the elementary groups.
Accordingly, as compared with the previously proposed
structure, the auxiliary color selection grid is in the beam
path disposed not in back but ahead of the Venetian blind
grid, that is, at the side facing the cathode. This ar
3,090,8‘J0
COLOR TELEVISION TUBE HAVING VENETIAN
BLEND-TYPE GRID
Werner Veith, Munich, and Hinrich Heynisch, Grafel?ng,
near Munich, Germany, assignors t0 Siemensdz Halske
Aktiengesellschatt, Berlin and Munich, a corporation of
Germany
Filed July 7, 1960, Ser. No. 41,395
Claims priority, application Germany Sept. 25, 1959
4 Claims. (Cl. 315-41)
rangement has as contrasted with the ?rst noted grouping
the considerable advantage, ?rst, that the grid can have
an irregular structure, that is, that it need not be matched
10 to and adjusted to the subdivision of the Venetian blind
This invention is concerned 1with a color television tube.
The following considerations ‘will aid the understanding
of the invention:
An electron beam tube for reproducing color television
pictures has been proposed before, comprising, in addition 15
to the focusing and de?ection means which are custom
grid, and second, that only relatively low volt-ages are
required for eifecting its control. It is moreover im
portant for the imaging mechanism that this grid is not
positioned in the imaging path of the electrons.
The various objects and features of the invention will
appear from the description which is rendered below with
reference to the accompanying purely schematic draw
ings, in which:
arily employed in the case of monotone picture tubes,
at least one grid arranged in the beam path ahead of
and parallel to the screen electrode, such grid consisting
FIGPI shows the spatial arrangement ‘of the color se
of narrow mutually spaced apart metallic strips or slats 20 lection grid with respect to the remaining electrodes con
extending in the manner of a Venetian blind and being
tained in the tube; and
inclined to the tube axis so as to practically conceal part
FIG. 2 represents the potential conditions in the space
of the view in the direction of the tube axis, as in the
between the screen electrode and the color selection grid,
case of an incompletely opened Venetian blind, electrons
for the case of slowed electrons, that is, without the use
which are easily in?uenced appearing in the range of the 25 of secondary electrons.
Venetian blind grid which are on the screen side de?ected
In FIG. 1, numeral 1 indicates the tube envelope and
from the paths by the acceleration ?eld of the screen elec
2 the course of the electron beam which is in customary
trode and thereby focused so that they are, by further
manner produced by means of a generating system 3
means which periodically affect their acceleration (color
comprising, among others, a cathode, a control electrode
selection means), successively pictured upon individual 30 (Wehnelt cylinder), and an acceleration electrode, the
color strips of an elementary group of color strips of the , beam being thus accelerated and by suitable means
screen which is allocated to a gap formed by two respec
focused.
tively neighboring metallic slats. The prior picture tube
for example, a magnetic de?ection device positioned at
The beam is by means of a de?ection device,
provides for the color selection a grid arranged between
the transition irom the neck to the cone part of the tube,
the Venetian blind grid and the screen electrode and 35 de?ected so that it describes a rectangular raster in a
extending parallel to the latter, such grid being made of
parallel disposed galvanically interconnected wires, the
individual grid ‘wires being with uniform grid division
(pitch) respectively disposed in a plane formed by edges
of the metallic slats of the Venetian blind grid facing the
screen electrode and extending perpendicular thereto.
The electrons emerging from the gaps of the Venetian
blind grid are in operation affected by the iield of this
grid, due to a high frequency color selection voltage con
nected thereto, so that they alternately reach the proper
color strip belonging to the corresponding elementary
group.
Technical difficulties are experienced in the disposition
of the color selection grid, with respect to its division
(pitch), relative to the Venetian blind grid in the screen
electrode which is subdivided into elementary groups.
The object of the invention is to avoid these di?iculties
to a far reaching extent, that is, to reduce the amount of
plane extending approximately parallel to the tube base.
The beam is, however, by means of the cylindrical lens
electrode 4 in cooperation with‘the acceleration anode
in the beam generating system, slowed down, focused and
de?ected in a direction parallel to the tube axis, so that
it enters approximately perpendicular into the grid plane
of the color selection grid 6 and the grid 5 which is con
structed in the fashion of a Venetian blind.
The color
selection grid 6 consists of tensioned wires extending in
a common plane and interconnected galvanically; the
subdivision structure (pitch) of these grid Wires is in
dependent of that of the Venetian blind grid. Spaced
from the latter is the ?uorescent screen 7 which is pro
vided with conductive support 8, high voltage being
placed ‘on the screen so as to accelerate to the required
energy the electrons leaving the Venetian blind grid with
‘low initial velocity.
FIG. 2 shows in partial view the potential course be
adjustment work and possible error sources, by a con
tween the color selection grid 6, the Venetian blind grid
55
siderable simpli?cation of the auxiliary color selection
5, and the screen electrode 7, 8, assuming that the elec
means.
trons accelerated by the beam generating system are, in
This object is realized, in connection with the initially
‘the range of the Venetian blind grid, merely slowed down
described electron beam tube for reproducing color tele
to about 0 volt and cause, without the release of sec
vision pictures, by arranging, as seen in the beam direc
60 ondary electrons, responsive to appropriate successive ac
tion, in back of a cylindrical lens electrode and ahead of
celeration, the excitation of the ?uorescent screen. The
metallic strips or slats of the Venetian blind grid 5 are
grid) extending parallel thereto, such further grid com
for this purpose with respect to the cathode at a nega
prising parallel tensioned wires extending in vicarr of the
tive potential of, for example, —20 v., so that, as ‘already
division of the Venetian blind grid and the elementary 65 mentioned, no electrons (primary electrons) can reach
groups of the screen electrode not necessarily in a uni
them. The color selection grid 6 receives a positive po
the Venetian blind grid, a further grid (color selection
form structure and having a potential applied thereto
which is by a few volts different from that applied to the
Venetian blind grid, so that the slow electrons are in the
tential of, for example, +20 volts, that is, it will be by
the same amount more positive than the Venetian blind
grid is with respect to the cathode potential more nega—
range of the Venetian blind grid, by a high frequency 70 tive. This causes, in the region approximately ahead of
color selection voltage applied to the color selection grid,
the individual gaps formed in the Venetian blind grid,
with diiferent strength de?ectable with respect to the
appearance of saddle points in the potential ?eld, that is,
3,090,890
4
3
between ‘the color selection grid 6 and the metallic strips
5, which e?ect slowing down of the electron beam. The
boring metallic strips, comprising a further color selec
electrons assume due to slowing down at the saddle points
very low velocity, about +2 volts, and are thereupon
of said cylindrical lens electrode and ahead of said Vene
tian blind grid and parallel thereto, said further color
selection grid being formed of parallel extending ten
tion grid arranged as seen in‘lthe beam direction in back
again accelerated by the high potential of the picture
siOned Wires not necessarily extending regularly with re
spect to the division of the Venetian blind grid and the
elementary groups of the screen electrode and having a
common potential connected thereto which is by a few
screen and thus focused to the individual color strips ow
ing to the de?ection which ‘occurs ‘thereby.
According
ly, the potential of the Venetian blind grid is during op
eration always constant, while high frequency color se
lection voltage is solely connected to the color selection Hi volts di?erent from that carried by ‘the Venetian blind
grid, whereby the slow electrons are in the range of the
grid. However, the potential of the color selection grid
Venetian blind grid by a high frequency color selection
may conversely be held constant and the potential of the
voltage additionally connected to the color selection grid
color selection voltage may be correspondingly connected
with different strength ‘de?ected to the screen electrode
to the Venetian blind. It may likewise be advantageous
to vary both potentials of the respective electrodes ap
proximately symmetrical to [the cathode potential in ac
cordance with opposite values corresponding to the color
in accordance with the respective color strips of the ele
mentary groups.
2. An electron beam tube according to claim 1, where
in the Venetian blind grid is substantially at cathode po
selection voltage.
tential, the potential of the color selection grid ‘being
Changes may be made within the scope and spirit of
the appended claims which de?ne what is believed to be 20 thereby more positive by as many volts as the potential
‘of the Venetian blind grid is more negative than the cath
new and desired ‘to have protected by Letters Patent.
ode potential, whereby saddle points are created in the
We claim:
‘region of the Venetian blind grid in which is effected a
1. An electron beam tube ‘for reproducing color tele
slowing down of the electrons to only a few volts velocity.
vision pictures, having de?ection and focusing means cus
3. An electron beam tube according to claim 2, where
tomarily utilized in monotone picture tubes and having 25
in the color selection voltage is connected to one of the ’
a cylindrical lens electrode, and having at least one grid
electrodes constituting respectively the Venetian blind
arranged ahead of and extending in parallel with the pic
grid and the color selection grid, while the potential of
ture screen, said grid consisting of relatively narrow me
tallic strips which are mutually spaced apart to form gaps
the other respective electrode is held constant.
30
4. An electron beam tube according to claim 2, where
therebetween and which are inclined to the tube axis in
in the potential of the electrodes constituting respective
the manner of the slats of an incompletely opened Vene
(tian blind so as to practically shut off continuity in vthe
ly the Venetian blind grid and the color selection grid
is for the color selection variable symmetrical to the con
direction of the tube axis, wherein easily in?uenced elec—
rtrons appear in the range of the Venetian blind grid
stant cathode potential.
which are upon the screen side thereof de?ected from 35
References Cited in the ?le of this patent
their path by the acceleration ?eld of the screen electrode
and thereby focused so that they are by color selection
UNITED STATES PATENTS
means which periodically affect the acceleration there
of successively pictured upon individual color stripscf
an elementary group of color strips of the screen which
group is allocated to a gap formed by respectively neigh
40
2,617,948
2,813,224
Kallm-an ____________ __ Nov. 11, 1952
Francken ___________ __ Nov. 12, 1957
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