Improvements in Means or Apparatus for Obtaining and Projecting Chrono-photographic Images.
Year: 1898

page_text: Date of Application, 3rd Aug., 1898
Complete Specification Left, 29th Apr., 1899-Accepted, 3rd Aug., 1899
Improvements in Means or Apparatus for Obtaining and Projecting
Chrono-photographic Images.
I, BENJAMIN JOSEPH BARNARD MILLS, of 23, Southampton Buildings, in the
County of London, Patent Agent, do hereby declare the nature of this invention
(a communication to me from Auguste Lumière and Louis Lumière, Manu-
facturers of Photographic Products, of 21, Rue Saint-Victor, Lyon-Montplaisir, in
the Republic of France) to be as follows;-
-
The invention is applicable to apparatuses called "cinématographs" used in
obtaining and projecting animated pictures. It has for its object to permit in
these apparatuses the uniform and continuous travel of the ribbon intended to
receive the successive images or to project these images upon a screen.
To obtain the fixity of the projection in spite of the continued motion of the
image, it is necessary to deviate the projected rays a quantity which varies each
moment, according to the position which the image occupies at such moment.
This result is obtained by interposing in the passage of these rays, a prism
of special construction, the angular tangent of which varies proportionately to the
motion of the image, by means of a mechanism regulated by this same motion.
The accompanying drawings show the arrangements employed for this purpose.
Fig. 1 is a longitudinal section of the apparatus; Figures 2, 3 and 4 show
different phases of the operation.
The pellicle A which carries the successive images, moves vertically from top to
bottom impelled by the roller B provided with points which enter the regularly
spaced perforations of the pellicle, it is guided by known arrangements, and
passes behind an opening C, D the height of which is equal to that of two con-
secutive images.
In front of this opening is arranged the object glass O, and at the back an
ordinary lighting apparatus not shown in the drawing.
In front of the object glass is arranged the prism of variable angle, formed
of two sheets of glass a, a with parallel faces capable of oscillating separately on
two horizontal axes b, b, the sheets a are united at their edges by a rubber
membrane d, bellows-wise, so as to constitute a liquid tight box at the same
time leaving liberty of oscillation to the sheets; this box filled with water or
other non-colored liquid the index of refraction of which is conveniently chosen
forms a prism the faces of which can receive different inclinations, by means of
levers E E keyed on each of the oscillation axes b.
The levers É are operated by a double cam H mounted on a horizontal shaft F
receiving its movement from the drum B, by means of helicoidal gearing G G¹.
The cam H has the form of a drum the two edges of which are symmetrically
cut in helical form, the levers E bear on these edges by their interior face the
direction of which is parallel to the faces of the prism, and passes through the
centre of oscillation 6, the contact of the levers on the cam is assured by a
Bring K

page_text: The cam H makes one revolution during the passage of an image, its size and
the speed of the helices are such that in the middle of its motion, the faces a, a
of the prism are parallel, see Fig. 3 and that at the extreme points of the motion
see Figures 2 and 4 they form in one direction or the other the maximum angle
of deviation.
When the image I Fig. 2 occupies the upper part of the opening C D the
angle of the prism P is greatest and has its opening turned upwards see Fig. 2.
When the image has arrived at the centre of the opening Fig. 3, the prism has
its faces parallel and the deviation is nil.
When at last the image has arrived at the lower part of the opening, the
angle of the prism is greatest and has its opening turned downwards see
Fig. 4.
It is therefore possible by a convenient choice of the maximum angle of the
prism, to cause to coincide on the screen the projections of the image in these extreme
positions Figures 2 and 4, with its minimum projection Fig. 3. In the intermediary
positions the coincidence will necessarily take place, because by construction the
linear displacement of the image is proportionate to the angular tangent of the
prism, and that the motion of the projection on the screen is proportionate to the
angle of deviation of the rays. Now these two angles, at least within the useful
limits of size of the apparatus obviously vary in the same proportion.
At the end of cach turn, the prism returns briskly from the position Fig. 4 to
that at Fig. 2 so that the new image I¹ Fig. 4, may be projected in its turn.
The size of the extreme angles of the prism is fixed by construction, according
to the focal distance of the object glass, but it may be made to vary within certain
limits by lengthening or shortening the arms of the levers E, so as to permit
the regulation of the apparatus. This result is obtained by elevating or lowering
all the upper part of the apparatus, opening, object glass and prism, mounted for
this purpose on a movable support M. This regulation may take place during the
working of the apparatus by observing the projections on the screen. The
apparatus thus arranged can naturally serve for obtaining negative proofs of
animated scenes.
The error committed in admitting that the deviation is proportionate to the
angle of the prism, is of less importance in proportion as the variations of this
latter angle are smaller, hence a means of reducing this error by replacing the
single prism by two or a larger number of similar prisms the deviations of which
unite together to obtain the total deviation. The maximum angle of each of
these prisms is thus diminished as well as the error which results therefrom.
Each prism will in this case be actuated by a helicoidal cam similar to the
cam H, but of a much less motion which lessens the briskness of fall of the
levers E at the end of each rotation.
Dated thin 2.1
1800
HARRIS & MILLS,
23, Southampton Buildings, London, W.C.,
Agents.
Improvements in Means or Apparatus for Obtaining and Projecting
Chrono-photographic Images,
I, BENJAMIN JOSEPI BARNARD MILLS, of 23, Southampton Buildings, in the
County of London, Patent Agent, do hereby declare the nature of this invention
(a communication to me from Auguste Lumière and Louis Lumière, Manu-

page_text: facturers of Photographic Products, of 21, Rue Saint-Victor, Lyon-Montplaisir, in
the Republic of France) and in what manner the same is to be performed to be
particularly described and ascertained in and by the following statement:--
46
The invention is applicable to apparatuses called cinématographs" used in
obtaining and projecting animated pictures. It has for its object to permit in
these apparatuses the uniform and continuous travel of the ribbon intended to
receive the successive images or to project these images upon a screen.
To obtain the fixity of the projection notwithstanding the continued motion of the
image, it is necessary to deviate the projected rays a quantity which varies each
moment, according to the position which the image occupies at such moment.
This result is obtained by interposing in the passage of these rays, a prism
of special construction, the angular tangent of which varies proportionately to the
motion of the image, by means of a mechanism regulated by this same motion.
The drawings accompanying my Provisional Specification show the arrange-
ments employed for this purpose.
Fig. 1 is a longitudinal section of the apparatus. Figures 2, 3 and 4 show
different phases of the operation.
The film A which carries the successive images, moves vertically from top to
bottom impelled by the roller B provided with points which enter the regularly
spaced perforations of the film, it is guided by known arrangements, and
passes behind an opening CD the height of which is equal to that of two con-
secutive images or pictures.
In front of this opening is arranged the object glass 0, and at the back an
ordinary lighting apparatus not shown in the drawing.
In front of the object glass is arranged the prism P of variable angle, formed
of two sheets of glass a a with parallel faces capable of oscillating separately on
two horizontal axes b, b, the sheets a are united at their edges by a rubber
membrane d, bellows wise, so as to constitute a liquid tight box at the sanie
time leaving liberty of oscillation to the sheets; this box filled with water or
other non-colored liquid the index of refraction of which is conveniently chosen
forms a prism the faces of which can receive various inclinations, by means of
levers EE keyed on each of the oscillation axes b.
The levers are operated by a double cam H mounted on a horizontal shaft F
receiving its movement from the drum B, by means of helicoidal gearing G G¹.
The cam H has the form of a drum the two edges of which are symmetrically
cut in helical form, the levers E bear on these edges by their interior face the
direction of which is parallel to the faces of the prism, and passes through the
centre of oscillation b, the levers are kept in contact with the cam by a spring K.
The cam H makes one revolution during the passage of an image, its size and
the speed of the helices are such that in the middle of its motion the faces a, a
of the prism are parallel, see Fig. and that at the extreme points of the motion
see Figures 2 and 4 they form in one direction or the other the maximum angle
of deviation.
When the image I see Fig. 2 occupies the upper part of the opening C D the
angle of the prism P is greatest and has its opening turned upwards. When the
image has arrived at the centre of the opening see Fig. 3, the prism has its faces
parallel and the deviation is nil.
When at last the image has arrived at the lower part of the opening, the
angle of the prism is greatest and it has its opening turned downwards see Fig. 4.
It is therefor possible by a convenient choice of the maximum angle of the
prism, to cause to coincide on the screen the projections of the image in these extreme
positions, see Figures 2 and 4 with its medium projection Fig. 3. In the intermediary
positions the coincidence will necessarily take place, because by construction the
linear motion of the image is proportionate to the angular tangent of the prism,
and that the motion of the projection on the screen is proportionate to the angle
of deviation of the rays. Now these two angles, at least within the useful limits
of size of the apparatus obviously vary in the same proportion,

page_text: At the end of each turn, the prism returns briskly from the position shown
at Fig. 4 to that shown at Fig. 2 so that the new image I¹ Fig. 4, may be pro-
jected in its turn.
The size of the extreme angles of the prism is fixed by construction, according
to the focal distance of the object glass but it may be made to vary within certain
limits by lengthening or shortening the arms of the levers E, so as to permit
the regulation of the apparatus. This result is obtained by raising or lowering
all the upper part of the apparatus, comprising the opening, object glass and
prism, mounted for this purpose on a movable support M. This regulation may
take place during the working of the apparatus by observing the projections on
the screen. The apparatus thus arranged can naturally serve for obtaining
negatives of animated scenes.
The error committed in admitting that the deviation is proportionate to the
angle of the prism, is of less importance in proportion as the variations of this
latter angle are smaller, hence a means of reducing this error by replacing the
single prism by two or a larger number of similar prisms the deviations of which
unite together to obtain the total deviation. The maximum angle of each of
these prisms is thus diminished as well as the error which results therefrom.
Each prism will in this case be actuated by a helicoidal cam similar to the
cam H, but of a much smaller motion which lessens the briskness of fall of the
levers E at the end of each rotation.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed I declare that what
I claim is:
1. In apparatus for obtaining or projecting chrono-photographic or cinémato-
graph images in which the progress of the ribbon or film is continuous; the
deviation of the luminous rays by one or several liquid prisms of variable angle
formed of two sheets of glass united by a flexible membrane enclosing the liquid,
the said sheets being capable of oscillating symmetrically by means
mechanism in relation with that which moves the image, in such a way as to
form angles the tangent of which is proportionate to this motion.
of a
2. In apparatus for obtaining and projecting chrono-photographic or ciné-
matograph pictures in which the progress of the ribbon or film is continuous the
combination therewith of one or several liquid prisms of variable angle con-
structed and operating substantially as herein set forth and for the purpose
stated.
Dated this 29th day of April 1899.
i
HARRIS & MILLS,
23, Southampton Buildings, Loudon, W.C.,
Agents.