Improvements in and connected with Optical Projection Apparatus.
Year: 1899

page_text: Date of Application, 29th Aug., 1899
Complete Specification Left, 26th Mar., 1900-Accepted, 2nd June, 1900
PROVISIONAL SPECIFICATION.
Improvements in and connected with Optical Projection Apparatus.
I, JAN SZCZEPANIK, of III, Ungargasse 12, Vienna, Austria, Engineer, do
hereby declare the nature of this invention to be as follows:-
It is known that each portion of the opening in the diaphragm of an objective
is sufficient to project an image. Hence, according to the present invention,
in order to project simultaneously 2, 3, or even more images, the diaphragm or
the pencil of rays passing through the diaphragm, is divided into 2, 3, or more
portions by means of mirrors. Consequently each portion forms an image,
which can be reflected by means of mirrors upon any desired surfaces.
The accompanying drawing illustrates an example of an instrument for pro-
jecting two images according to this invention. abis the object, which in
the case represented is to be projected in duplicate. e is a lens or system of
lenses. d, is the diaphragm opening. g, h are two plane mirrors the edges
of which divide the diaphragm opening, or the pencil of rays passing through
the diaphragm, into two parts, j, k represent two lenses or systems of lenses.
It is obvious that the two lenses and yield exactly similar and sharp
images, which appear on the surfaces m and n. If, however, one wishes to
direct the said images upon one and the same surface, two mirrors and p
must be used in addition, which are parallel to the mirrors g, h.
means two images and y are reflected upon one surface.
By this
For different sizes the mirrors or lenses j, k must be moved away by equal
amounts from the axis, which can be done in a known way by means of toothed
wheels, spindles, or worms.
"
If "diapositive" (hereinafter called diapositives") are secured in place of
the negatives or images ry and illuminated by means of condensers, one obtains
from the two diapositives a common sharp image. In a similar way an apparatus
for three images can be constructed.
By means of such an instrument it is possible to photograph objects in natural
colours or to produce naturally coloured images thereof. This is done in the
following manner. A colour-filter for blue, yellow, and red is inserted in front
of each projected image. This takes place in front of the surface on which the
images are projected. The colour-filters may, however, be placed also behind
the diaphragm orifice d, f. If from the negative or negatives obtained, one
produce three diapositives. all three images will, if three colour plates be used,
be differently coloured and the same will jointly yield, as is known, an image
in natural colours. Since only a portion of the diaphragm is used, the luminous
intensity of each individual image is small. In spite of this it is possible to
project very intense images by using a special source of light for each diaposi-
tive. Thus in this way one has at disposal three sources of light instead of one.
Since the exposure for different colours is different, the diaphragm opening,
or the pencil of rays proceeding therethrough, must be divided by the mirrors

page_text: images. This is done in the following manner. Three colour-filters for blue,
yellow, and red respectively are inserted one before each projected image and
either in front of the surface on which the images are projected or just behind
the diaphragm orifice d f. If from the negatives obtained, one produce three
transparencies, all the three images resulting from these three negatives when
placed in the position of the negatives from which they will have been pro-
duced, will if three colour plates be used, be differently coloured and will jointly
yield, as is known, an image in natural colours. Since only a portion of the
diaphragm is used, the luminous intensity of each individual image is small. In
spite of this it is possible to project very luminous images by using a special source
of light for each transparency. In this way one has at disposal three sources
of light instead of one.
Since the exposures for different colours are different, the pencil of rays
proceeding through the diaphragm opening must be divided by the mirrors in
such a manner that the effects of the exposures for all the openings are equal
in the same time for all three colours.
To take the photograph for each colour separately, the corresponding colour-
filter may be inserted in front of the objective and the two other images that
are not to be photographed be prevented from appearing by suitable diaphragms.
The apparatus herein before described can also be used to produce two or more
similar images simultaneously, also to produce simultaneously several images
with different stoppings-off, and further for making use of one image for focus-
sing on the focussing screen and the other for photographing.
By means of the apparatus described it is possible, by using a suitable
instantaneous shutter in place of the diaphragms, to project several images on
after another upon a surface from a plate or film, the plate or film changing
taking place only after the illumination of all the 3, 4, or more images that the
apparatus yields. By this means the number of plate changes is smaller, which
may be made use of for kinematographs, with which, as is known, the images
appear less sharp the more quickly the pictures are changed.
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed I declare that what
1 claim is-
1. Apparatus for projecting several images with one objective, in which by
means of two or more mirrors placed at an angle to one another and opposite
to the diaphragm orifice, the pencil of rays that comes through the diaphragm-
orifice is divided into several portions and the several portions are, by special
lenses, thrown on separate surfaces, or, by means of mirrors, separately reflected
upon a common surface.
2. Optical projection apparatus constructed and arranged substantially as herein-
before described with reference to and shown in the drawings filed with my
Provisional Specification.
F. WISE HOWORTH,
46, Lincoln's Inn Fields, London, W.C., Agent for the Applicant.