US1963485A - Moving picture apparatus - Google Patents

Description

June 19, 1 M. BOWMAN-MANIFOLD ET AL 1,963,485

MOVING PICTURE APPARATUS Filed July 9, 1930 5 Sheets-Sheet l Z. m m Toes:

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' MOVING PICTURE APPARATUS Filed July 9, 1930 5 Sheets-Sheet 5 AA BB' 5 Sheets-Sheet 4 131,01. 6 flTTOE/VEK June 19, 19 M. BOWMAN-MANIFOLD ET AL MOVING PICTURE APPARATUS Filed July 9, 1950 June 19, 1934. M. BOWMAN-MANIFOLD ET AL 1,963,485

MOVING PICTURE APPARATUS Filed July 9, 1950 5 Sheets-Sheet 5 Patented June 19, 1934 UNITED STATES PATENT OFFICE MOVING PICTURE APPARATUS New Jersey Application July 9, 1930, Serial No. 466,626

In Great Britain July 10, 1929 14 Claims.

The present invention relates to apparatus for taking, projecting or viewing moving pictures. Such apparatus may be referred to generally as cinematographic apparatus.

For simplicity the word film will be used to designate any member, whether in the form of a long strip, a drum, a disc, or an endless loop, for example, upon wh ch a moving picture record is to be made, or from which a moving picture image is to be projected or viewed.

It is an object of the present invention to provide improved apparatus for projection or viewing in which stationary images, substantially free from optical distortion, may be produced from a continuously moving film without the use of oscillating or intermittently moving parts.

Alternatively, it is an object of this invention to provide new means of producing moving picture negatives by photography on continuously moving film without the use of oscillating or intermlttently moving parts.

According to the present invention, the cinematographic apparatus comprises one or more rotatably mounted mirrors disposed radially with respect to their axis of rotaton, and means for moving a film (or that part thereof which is at any instant operative), or an image thereof, along a path adjacent to the mirror or mirrors at twice the angular speed of said mirror or mirrors with respect to said axis.

The invention will be described by way of example with reference to the accompanying drawings in which Fig. 1 is a diagram illustrating the principles of the invention,

Figs. 2 and 3 are diagrammatical views in elevation and plan, respectively, further illustrat'ng the principles of the invention,

Figs. 4, 5 and 6 are diagrams in front elevation, side elevation, and plan, respectively, illustrating further features of the'invention,

Figs. 7 and 8 show, somewhat diagrammatically, constructional embodiments of the invention,

Fig. 9 is a plan view of the arrangement shown in Fig. 8.

Fig. 10 is a detail view to an enlarged scale of one of the mirrors which may be used in apparatus according to the invention, and

Fig. 11 shows, diagrammatically, further constructional embodiments of the invention.

In a simple form of the invention, illustrated in Fig. 1, a film 1 in the form of a long, continuous strip, is passed around the outside of a 65 drum 2 with angular velocity W, the film being passed round suitable rollers 3 disposed between the drum and wind-on and wind-off spools respectively (which are not shown in this figure) so that the film is in contact with the drum over a considerable portion of its circumference. 00 A plane mirror 4 is rotatably mounted within the drum and is arranged symmetrically with rei spect to the drum axis, so that the reflecting surface contains the drum axis. The mirror axis is coincident with the drum axis and the mirror is adapted to be rotated at half the angular speed of the drum and in the same direction.

Light, indicated by lines C, from a suitable source external to the drum is passed through the film 1 and, when the mirror 4 is suitably situated during its rotation, is reflected by the mirror through a projecting lens, or objective 5, on to a screen. The periphery of the drum 2 is, of course, either of transparent material or is provided with suitable windows.

With this arrangement, a stationary virtual image of the particular frame A B of the travelling film which is at any time illuminated is formed upon the drum surface at A B. Light from this stationary image will pass into the so objective 5 and thence on to a screen, which is not shown, when the mirror is in the above mentioned suitable position of rotation.

If the mirror reflects on one side only, points on the film at a distance from one another equal to as twice the drum circumference will have fixed images at the same point. With this arrangement, therefore, the successive frames would require a pitch (or distance from centre to centre) equal to twice the drum circumference. In order to obtain this in practice, either the length of each frame must be great in relation to the drum size (which would not usually be satisfactory) or a relatively large space would have to be left between successive frames of the same picture or episode. The space may of course, if desired, be used for one or more other pictures, in which case the total film length would be u times that necessary for one episode but, on the other hand, one film would carry it different episodes.

To enable the frames successively projected to be arranged closer together, as is customary, apparatus using a number of radially disposed plane mirrors is preferably used, as illustrated in Figs. 2' and 3. In this case, a number of mirrors 4 are arranged radially about the axis of rotation of the film 1 between rollers 3. The mirrors, of which there may be any convenient number, forty-eight being shown in this diagram, are

equally spaced and extend about four thirds of the length of a picture frame from the inside of the drum circumference towards the axis thereof, so that a cylindrical space bounded by the envelope of their inner edges is left within the mirrors. In order that every frame may be projected in turn, the circumference of the circle in which the film moves must be equal to half the product of the number of mirrors and the distance between successive frames. Other parts may be as already described.

During a short are of its travel, the film 1 is illuminated from C, the source being so arranged that the light, after passing through the film, falls obliquely on one of the radial mirrors and forms a stationary virtual image of the illuminated frame AB at A B on the drum circumference. Each frame will form, in turn in a corresponding mirror, an image in the same position, while light from this image will pass into the cylindrical space within the mirrors. In order that this light may not be obstructed by any of the other mirrors, the back surface of the inner and outer edges of each mirror may be bevelled (as shown at '7 in Fig. 10, the reflecting surface being indicated in this figure by d), and the direction of the light may be changed, for example, by means of a fixed plane mirror 8 disposed within the cylindrical space at an angle of 45 to the axis. This stationary mirror will reflect light in a direction sensibly parallel to the axis. A projecting lens 5 is placed so that it receives light from the stationary mirror and forms a'final real image upon the screen. Alternatively, the projection lens 5 may be placed between the radial mirrors 4 and the plane mirror 8.

The mirrors 4 may be formed of stainless steel.

It will be seen that if the length of film illuminated at one time is small compared to the radius of the circle containing the outer edges of the mirror, then a close approximation to the above result may be obtained by moving the film along a path which is not circular and may even be linear. In the latter case, the speed of the film must be such that the angular velocity of a point on it is twice that of the mirror.

The obliquity of the virtual image formed by the radial plane reflecting surfaces may be avoided or reduced and thus substantially evenly focussed final images may be formed, after reflection from the radial mirrors, in a plane normal to the reflected beam, by replacing the moving film by a rotating series of images of the successive frames, as shown in Figs. 4, 5 and 6. In this arrangement, two drums (of which only portions are shown) are used rotating about a common axis one above the other (Fig. 6). The lower drum 2 upon which the film 1 rotates is provided with a number of identical optical systems of which only one is shown in the diagram, the angular pitch of these optical systems being equal to the angular pitch of the frames on the film. The optical systems may be arranged to form images in any desired position, and these images, in any case, rotate in the same direction and with the same angular velocity as the film. A system of radial mirrors, as described in the last example, of which only one indicated by 4 is shown, rotate within the upper drum 9 in the same direction and with half the angular velocity of the film or its image. Each optical system attached to the film drum comprises a cylindrical lens 10 adapted to remove the curvature of the image produced from the curved film, a mirror 11 inclined relatively to the axis and also relatively to the tangent to the drum at the centre of the active frame, and a lens 12. Each system forms a moving image of a frame at A B and this image serves as the object for the system of radial mirrors disposed within the upper drum and replaces the actual film image described in the previous examples. A stationary image A B of the object A B is formed in the radial mirrors 4. The inclined mirrors 11 upon the film drum serve to throw the light from a source 13, arranged outside the drum, after passing through the film 1 and the cylindrical lens 10, in a direction oblique to the axis of the drum so that it falls obliquely upon one of the radial mirrors 4. Light from the image A B formed by the radial mirrors 4 passes, again in a direction oblique to the drum axis, through a suitable stationary projecting lens 5.

In a modification of the arrangement last described, instead of the optical systems being rotated with the film, a single fixed optical system may be used which will also produce images which move in the same direction and with the same angular velocity as the film, but the system must not contain a plane mirror. The radial mirrors are therefore rotated as before in the same direction as the images and at half their angular speed.

Any stationary plane mirror in the optical system reverses the direction of motion of the images, and, where such a mirror is used, the radial mirrors must be rotated in the opposite irection to the film.

The obliquity of the stationary images may be corrected more simply by inserting a prism of certain thickness and face angles between the film and projecting lens in such a manner that the stationary images are formed in a plane which is normal to the direction of viewing.

Fig. 7 shows the general arrangement of apparatus in one form of the invention. The film l is driven by the sprocket l4 and travels from the spool 15 by rollers 3, over the stationary cylindrical guide drum 2, past a single gate aperture 16, and into a spool casing 17. The circumference of the cylindrical guide drum is thirty frames in length. A spring loaded pad 18 presses the film against the guide drum 2. The roller 3 shown in the upper right hand corner of Fig. 7 is adjustable and is used to alter the length of film between the driving sprocket and the gate aperture. By this means, a complete picture can be brought opposite the gate aperture when the radial mirrors are in the correct position for reflecting a complete pcture, the film being thereby correctly framed. The film is illuminated as it passes the gate aperture by light from a source in the lamp housing 20 containing a condensing lens 21. sixty stainless steel mirrors 4, is rotated, by means of suitable gearing, concentric with and inside the cylindrical guide at half the angular speed of the film. At the gate, the reflecting faces of the mirrors are upwards and reflect light which passes onto them from the film onto the projecting optical system. This system consists of a lens 5 with its axis horizontal, a plane m rror 8 which stands in a vertical plane inclined at 45 to the lens axis, and an obliquity correcting prism (not shown, but which is placed between the lens 5 and mirrors 4). The combined movements of the film and disc of mirrors is such that the light received by the projecting lens 5 comes normally from a stationary virtual image of the illumi- A disc 6, on which are supported nated part of the film. The final image is formed on a vertical screen as usual.

In a modification (illustrated in Fig. 11) of the above described apparatus,.the drum 2, which serves as guide for the film (which is not shown in this figure), is adapted to be rotated at the same speed as the film. To obtain this, the said drum carries on its circumference two rows of sprocket teeth 28 which engage perforations in the film thus serving to drive the film and avoiding the necessity of a separate driving sprocket In this case, the drum has a series of gate apertures 16 cut in it, the angular pitch of these apertures being the same as the angular pitch of the frames on the film.

The radial mirrors 4 are attached to the inner surface of a hollow spindle 29, and the obliquity correcting prism 26 (with which is combined a reflecting surface 8) and the projecting lens 5 are mounted within the cylindrical space formed by the inner edges of the radial mirrors, the final beam of light thus emerging from the apparatus in a direction sensibly parallel to the axis of the spindle. The guide drum 2, which carries the fllm, is mounted upon or made an integral part of a member 30 which is mounted coaxially with and around the hollow spindle 29. By means of suitable gearing 31, the spindle 29,carrying the radial mirrors, is made to rotate with angular velocity and the outer member 30, carrying the film, is made to rotate in the same direction with angular velocity W. Light, emanating from within a housing 20, passes through the moving film and one of the apertures 16 and falls obliquely upon one of the radial mirrors 4. Since the radial mirrors move with half the angular velocity of the film, a stationary virtual image of the fllm is formed on the drum circumference and this image is projected through the prism 26 and lens 5 on to a viewing screen.

Figs. 8 and 9 illustrate another type of projector in which the film may be illuminated by transmitted light or in which pictures upon an opaque carrier, such as a paper strip, may be' illuminated by reflected light. In these figures, two alternative positions for a lamp housing containing a suitable source of light are shown at 20 and 22. If film is to be illuminated, light from the housing at 20 (shown by the dotted lines) is reflected from the plane mirror 23 through the film; if paper strip is to be illuminated, light from the housing at 22 falls directly on to the inner face of the paper. The film or paper strip is wound off the spool 15, along rollers 3, over the guide 2, and into the spool 27, and it may be rewound along the track over the rollers 24. The screw 25 is used for adjusting the position of the lens 5, and 26 is the obliquity correcting prism. The disc 6 carrying the radial mirrors is mounted on a hollow spindle, and mirror 8 reflects the emergent beam in a direction sensibly parallel to the axis of said spindle, the final image being formed on a vertical screen which is perpendicular to said axis.

There are many possible modifications of the invention other than those herein described. For example, the film may be run inside the radial mirror system instead of outside it. Furthermore, it will be clear that the axis about which the radial mirrors and the film or image thereof rotate, which has been assumed, in the above examples, to be-horizontal, may be in any direction.

Although the invention has been described with particular reference to projection, it will be evident that similar apparatus can be used for viewing or as a camera.

When the invention is used in a camera it is necessary to restrict the gate aperture to half the distance between successive frames to avoid overlapping of images.

We claim:

1. In a cinematographic apparatus, the combination of a drum, a plurality of reflectors positioned within said drum in equally spaced relation and extending radially therein a distance short of the radius thereof, said reflectors all having their respective reflecting surfaces facing in the same direction, means for rotating said reflectors at a predetermined speed, and means for moving the film over said drum at a speed different than but complemental to the speed of said reflectors.

2. a cinematographic apparatus, the combination of a drum, a plurality of reflectors positioned within said drum in close proximity to the inner wall thereof and in equally spaced relation, said reflectors extending radially within said drum a distance short of the radius thereof and having their respective reflecting surfaces facing in the same direction, means for rotating said reflectors at a predetermined speed, and means for moving the film over said drum at a speed different than but complemental to the speed of said reflectors.

3. In a cinematographic apparatus, the com-. bination with a drum and a film movable thereover and having a plurality of substantially uni.

formly positioned picture frames thereon, of a rotatably mounted supporting member concentric with said drum, and a plurality of reflectors mounted on said member in equally spaced relation and extending within said drum adjacent the inner wall thereof and in a radial direction, the circumference of the circle in which said film moves being numerically equal to half the product of the number of reflectors on said member and the distance between successive frames on said film.

4. In a cinematographic apparatus, the combination of a fixed drum having an aperture in the wall thereof and being openat its ends, a rotatably mounted supporting member adjacent one end of said drum and concentric therewith, and a plurality of reflectors mounted on said member in equally spaced relation and extending within said drum adjacent the inner wall thereof and in a radial direction therein, the outer wall of said drum being adapted to serve as a guide for the passage of a film thereover,

5. In a cinematographic apparatus, the combination of a fixed drum having an aperture in the wall thereof and being open at its ends, a rotatably mounted supporting member adjacent one end of said drum and concentric therewith, a plurality of reflectors mounted on said member in equally spaced relation and extending within said drum adjacent the inner wall thereof and in a radial direction therein, the outer wall of said drum being adapted to serve as a guide for the passage of afilm thereover, means for rotating said member, and means for feeding said film over said drum.

6. In a cinematographic apparatus, the combination of a rotatably mounted drum open at its ends, a plurality of apertures in the wall of said drum, a rotatably mounted supporting member adjacent one end of saiddrum and concentric therewith, a plurality of reflectors mounted on said member in equally spaced relation and extending within said drum adjacent the inner wall thereof and in a radial direction therein, means for rotating said member whereby said reflectors are rotated therewith, and means for rotating said drum at a speed different than but complemental to the speed of said reflectors.

'I. In a cinematographic apparatus, the combination of a rotatably mounted drum open at its ends, a plurality of apertures in the wall of said drum, means on said drum for advancing a film therewith in registration with said apertures, a rotatably mounted supporting member adjacent one end of said drum and concentric therewith, a plurality of reflectors mounted on said member in equally spaced relation and extending within said drum adjacent the inner wall thereof and in a radial direction therein, means for retating said member whereby said reflectors are rotated therewith, and means for rotating said drum at a speed different than but complemental to the speed of said reflectors.

8. In a cinematographic apparatus, the combination of a drum and a plurality of reflectors mounted within said drum adjacent the inner wall thereof and extending radially therein a distance short of the radius of said drum, whereby a space is provided concentric with said drum and defined by the ends of said reflectors removed from said wall, said reflectors being equally spaced from each other and having their re spective reflecting surfaces facing in the same direction.

9. In a cinematographic apparatus, the combination of a drum, a plurality of reflectors mounted within said drum adjacent the inner wall thereof and extending radially therein a distance short of the radius of said drum, whereby a space is provided concentric with said drum and defined by the ends of said reflectors removed from said wall, said reflectors being equally spaced from each other and having their respective reflecting surfaces facing in the same direction, and a fixed optical system within said space.

10. In a cinematographic apparatus, the combination of a drum, a plurality of reflectors mounted within said drum adjacent the inner wall thereof and extending radially therein, said reflectors being equally spaced from each other and having their respective reflecting surfaces facing in the same direction, a second drum spaced laterally from but concentric with said first drum, a film movable over said second drum, and optical means associated with said second drum for projecting an image of said film onto said radial reflectors.

11. In a cinematographic apparatus, the combination of a drum, a plurality of reflectors mounted within said drum adjacent the inner wall thereof and extending radially therein, said reflectors being equally spaced from each other and having their respective reflecting surfaces facing inthe same direction, a second drum spaced laterally from but concentric with said first drum, said second drum being rotatably mounted, means for rotating said drum, a film movable over said second drum, and a plurality of optical devices associated with said second drum for projecting an image of said film onto said radial reflectors as said second drum is rotated.

12. Apparatus according to claim 10 wherein said optical means and said reflectors are so related that an image is projected by said optical means onto said reflectors in a direction such that a substantially evenly focused final image is formed, after reflection from said radial reflectors, in a plane normal to the reflected beam.

13. In a cinematographic apparatus, the combination of a drum having an aperture in the wall thereof and being open at its ends, a rotatably mounted supporting member adjacent one end of said drum and concentric therewith, a plurality of reflectors mounted on said memher in equally spaced relation and extending within said drum adjacent the inner wall thereof in a radial direction therein a distance short of the radius of said drum, whereby a space is provided concentric with said drum, a film movable over said drum, means for feeding said film over said drum, a source of illumination in alignment with said drum aperture, and optical means located within said space for directing a light beam from said source out of said drum through the open end thereof removed from said supporting member.

14. In a cinematographic apparatus, the combination of a drum having an aperture in the wall thereof and being open at its ends, a rotatably mounted supporting member adjacent one end of said drum and concentric therewith, a plurality of reflectors mounted on said member in equally spaced relation and extending within said drum adjacent the inner wall thereof in a radial direction therein a distance short of the radius of said drum, whereby a space is provided concentric with said drum, a film movable over said drum, means for feeding said film over said drum, a source of ilumination in alignment with said drum aperture, and optical means located within said space for directing a light beam from said source out of said drum through the open end thereof removed from said supporting member and in a direction substantially parallel to the axis of rotation of said radial reflectors.

MICHAEL BOWMAN-MANIFOLD. WILLIAM FRANCIS TEDHAM.

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