вход по аккаунту


Патент USA US2129035

код для вставки
Sept. 6, 1938.
Filed Nov. 1, 1935
mam ~v
Patented Sept. 6, 1938
Kurt Schlesinger, Berlin, Germany, assignor to
Radioaktiengesellschaft D. ’S. Loewe, Berlin
Steglitz, Germany
Application November 1, 1935, Serial No. 47,789
In Germany November 2, 1934
1 Claim.
(01. its-7.1)
The present invention relates to a television ing line I3 is projected with excessive brightness
by means of the optical system illustrated in Fig.
transmitter according to the method of inter
laced lines, which has already been described in ‘ 1. According to the invention, the ‘radial length
principle in the application Ser. No. 36,008/35 ‘ of this starting line It is made to be greater than
and which produces the synchronizing impulses the height of the image area l2. The line im~
pulses are, as well known, produced when the disc
by an optical method.
The invention will be explained by means of apertures pass the margin l3. Now to generate
the image change impulses there are employed
the accompanying drawing, in which
two tangential slits l4 and I5 which are arranged
Fig. 1 is a diagram showing a longitudinal sec
tion of the optical arrangement according to the in the disc 9 outside of the area l2 but just
within the starting line l3 which are displaced
invention, whilst
Fig. 2 is a plane view of the scanning disc and to one another to the extent of exactly the length
Fig. 3 of the rotating diaphragm described in of one half image line, and which possess a width
sometimes larger than a scanning aperture, such
the speci?cation.
In Fig. 1 there is illustrated a possible form of as may be conveniently produced in a mechaniembodiment of the arrangement according to cal stamping operation.
When the image change slits l4 and i5 pass
the invention. The light of the arc-lamp l is
projected evenly by a hollow re?ector 2 over the the extended starting line l3 there must impinge
surface of the film 3 and a slotted diaphragm 4. on the photo-cell, in accordance with the above,
a very much greater amount of light than when
The light passing through the latter is so de
?ected by means of two prisms 5 and 6 that the a scanning aperture passes the starting line, as
both the width of the starting line l3 as well as
diaphragm 4 is reproduced sharply simultaneous
ly with the ?lm through the main lenses 1 and the height of the slits I4, 15 equal the width of
8 on the screen of the Nipkow disc 9, so that it several image points. There thus immediately
appears as a white margin I3 (Fig. 2) close to a would take place the described “choking” of the
vertical edge of the ?lm image I2. By means of photo-ampli?er H. According to the invention
this is avoided by a regulable weakening of the
an auxiliary cylindrical lens It), the light inten
sity passing the. slot 4 is increased to such an light of the starting line l3. In Fig. 1 there are
shown two screws l6 (one covered by the other
extent that it by far exceeds all intensities pass
one), which may be turned into the path of light
ing the ?lm 3.
According to the invention the two groups 011 over the slotted diaphragm 4. The shadow of
these screws appears, therefore, on the surface
signals for synchronization, viz., the line im
of the disc as I6 i6’, as shown in Fig. 2. In this
pulses and the image-change impulses are pro
duced at the same amplitude by the following way it is easily made possible to equal the po
tential of either of the long signals to that of the
reasons. It has been found in practical opera
tion that a “choking” of the ampli?er H is not short signals. As addition to the described ar
to be avoided when the image-change impulses rangement there must be employed a diaphragm,
possess a considerably greater amplitude than which is designated 18 in Fig. l, synchronously
the line signals. The amount of current carried rotating at half the circumferential velocity of
by these long signals is suf?cient in order, by the Nipkow disc 9.
Fig. 3 shows the form of the diaphragm. The
extensive charging of the coupling condenser of
the ampli?er H, to cause a blocking of the same, diaphragm contains two spiral apertures H),
which fades but slowly. A second interference which serve to expose alternately one of the ap
in operation always exists when the method of erture spirals of the Nipkow disc. Further, it
contains two windows 29 and El exposing alproduction in respect of the two synchroniza
ternately one of the apertures l4 and i5 (Fig.
tion signals is not of such a kind that these sig
nals are given completely independently of the 2). (If the sequence of frame change impulses
image signals amplitude. Any superposition of is desired to be reversed, the windows are to be
the image and the synchronization signals must placed at Ma and Zia.) The spokes 22 and
23, which connect the outer edge with the
be avoided.
In Fig. 2 the Nipkow disc 9 is shown in a front inner portion of the diaphragm, are prefer
ably so disposed that the shadow formed by
View. It is provided with a double-spiral of aper
tures as described in the application Ser. No. the same impinges on the disc following the pass
ing of the windows 20, 2|. In this way there
36,008/35. The spirals of‘ this disc de?ne a trap
occurs an automatic darkening of the later porezoidal screen l2, at the edge of which the start
tions of the return line. It is sufficient if these
spokes are two or three image points in width,
inasmuch as the same are relieved mechanically
in the case of a steady rotation. The spokes as
UK shown apply to- the ?rst stated form of dia
phragm. For the complementary diaphragm the
spokes must be disposed behind the windows 20a,
21a. The distance of the diaphragm from the
disc must be made as small as possible, as other
lo wise there will be loss of light and lack of sharp
?lm images according to the interlaced line
method comprising a scanning disc provided with
a spiral of apertures having two turns, a spiral
aperture disc rotating at half the speed of the
scanning disc and uncovering at once one of said
apertures, a photo-cell arranged in operative re
lationship thereto, and means for projecting an
image of the ?lm to be transmitted onto said
scanning disc; means for simultaneously project
ing a light margin of great brightness onto said 10
ness of the shadows. The optical system accord ,. disc close to one radial edge of said image projec
ing to the invention provides otherwise a guar
tion. and .outreaching said edge, two circumfer
antee for the accuracy of the signals by reason of ential scanning slits in said disc having a tan
the main Nipkow disc 9 alone, on which there is gential distance one from another corresponding
located the sharp optical reproduction. The dia
to exactly the half of an image line and being 15
phragm I8 has no in?uence on the accuracy of arranged outside the area of the image projec
the signals, but has the function merely of‘ a tion so as to obtain. frame change impulses by
periodical covering for undesirable-passage. slots. the same said photo-cell when said margin is
The same, therefore, may be produced from a passed by said slits, and two windows in said ro
?exible material with comparatively small degree tating diaphragm so arranged as to expose alter 20
of‘ accuracy, and,
therefore, more simple and nately one of‘ said circumferential slits.
cheaper than the Nipkow disc 9.
I claim:
In a television transmitter for transmitting
Без категории
Размер файла
241 Кб
Пожаловаться на содержимое документа