US1580242A - Stereoscopic cinematographic apparatus - Google Patents

Description

April 13,1926.

M.' GIRSDANSKY STEREOSCOPIC CINEMATOGRAPHIC AFPARATQS Filed March 12, 19 21 5 Sheets-sheaf. 1

D uf/uDDDDDDuUr OGDDDG DDGD R INVENTUR ATTORNEYS April 13 1926.

M. GIRSDANSKY STERECSCOPIG CINEMATOGRAPHIC APPARATUS Filed March 12, 1321 v 5 Sheets-Sheet 2 v mvtpron BY XL A; man E-YHS April 13,1926.

M.--GlR$DAN-SKY STEHEOSCOPIC CINEMATOGRAPHIC APPARATUS 5 Sheets-Shet 5 Filed March 12 1921 46; ATTORNEYS April 13, 1926. 1,580,242

M. GIRSDANSKY STEREOSGOPIC CINEMATOGRAPHIC APPARATUS Filed March 12 1321 5 Sheets-Sheet 4 INVENTOR April 13,1926. 1,580,242

M. GIRSDANSKY STEREOSCOPIC CINEMATOGRAPHIC APPARATUS Filed March 12, 1921 5 Sheets-Sheet 5 165w I64 INVENTOR I BY % ATTORNEYS tionul view taken 011 the line 11 of Fig. 4.

Patented Apr. 13, 1926.

' UNITED STATES MAXIMILLIAN GIRSDANSKY, OF NEW YORK, N. Y.

STEREOSGOPIG CINEMATOGRAPHIG APPARATUS.

' Application filed March 12, 1921. Serial No. 451,755.

To all 1071 am it may concern:

Be it known that I, MAxiMInnmN Gins- DANSKY, a citizen of the United States of America, residing at New York, in the county and State of New York, have invented certain new and useful Improvements in Stereoscopic Cinematographic Apparatus, of which the following is a full, clear, and exact description.

This invention relates to cinematography and has for one of its principal objects to provide a method and means whereby images of a stationary or moving object may be obtained and projected upon a screen to produce stereoscopic pictures.

From a more specific aspect, a further object is to provide a method in which the ordinary cameras and projecting apparatus, now well known in the art, may be employed. by adding certain means hereinafter disclosed. Other objects and advantages will appear upon inspection of the following description.

Referring to the drawings which illustrate what I now consider preferred physical embodiments for carrying the .invention into practice:

Fig. 1 is a diagrammatic, horizontal see- Fig. l is a view similar to Fig. 1 but illustrating aniodification.

Fig. 2 -is a detail view of a cinematographic film showing the relative position of alternating in'iages of the same object.

Fig. 3 is a view illustrating the stereoscopic images as they would appear when projected upon a screen.

Fig. 4 is a fragmentary VOl'tlCHl'SGCtlOH ot a motion picture camera embodying one form of retracting means.

Fig. 5 is a fragmentary frontelevation of a motion picture camera or projecting apparatus embodying a modified and pre ferred form of refracting means.

Fig. 6 is a diagrammatic view representing a section taken on the line 6-6 of Fig. 5.

Figs. 7 and 8 are views similar to Fig. 6 but illustrating modifications.

Fig. 9 is a diagrammatic elevation showing how the retracting devices shown in Fig. 5 may be modified.

Fig. 10 is a view similar to Figs. 6. 7 and i 8 but illustrating a further modification.

'The invention may be best understood by referring first to Figs. 1, 2 and 3. In

Fig. 1 I have diagrammatically indicated a camera comprising the usual film gate 11), through which a negative iihn 11 is adapt ed to be passed, and an Optical system including one or morecamera lenses 12.. l mount in front of the lens 12, a retracting means shown, in this figure, in the form of a prism 13 of glass or other suitable refractive material. Assume that it-is dcsiredto produce stereoscopic pictures of an object 0, located for convenience in illust-ration on the optical axis A.A of the camera. F or further convenience assume that the object O is stationary, .it being understood that the object may be moving. I f the negative 11 is exposed when the re.- fracting means or prism 13 is in the full. line position, a ray of light passing from the object 0 along the optical axis will pass through the prism 13, being bent or refracted thereby toward the thick edge of the prism, thence through the lens 12 and thence to the negative film 11. where an image of the object 0 will be formed at 14. The light is now out off from the negatiie film 11 and the latter is shifted one image space, and the prism 13 moved to the dotted line position. When the film and prism are stationary exposure again takes place. The image of the object 0 will now be produced at 15 upon the negative film 11. The light is again cut oil from the negative film, the latter shifted one image space, and the prism 13 moved back to its full line position. Exposure then again takcsplacc, an image of the object O appearing at 14. When the desired length of film has been exposed it may be removed from the camera and developed and fixed in any of the well known ways. The negative film would then appear as indicated 'diagramimttically in Fig. 2. It. will be noted that, instead of being in vertical alignment, theimages of the object are displaced alternately to the right and left. For convenience I shall. refer to one set of alternate images or image spaces at R and. the other series as L. A positive film may now be printed, say by contact printing, from the negative and the two seriesfof images would hear the same relative positions as those shown on the negative in Fig. 2. 5

.ln projecting the positive iu'iagcs upon the screen any suitable cinematographic n'o'jector, or projecting apparatus now well known iirtlie art may be employed by providing certain additional apparatus one form of which I will now describe. For convenience in description it may be assumed that a projector is} diagrammatically illustrated in Fig.

. 1 (the source of light not being shown). As-

smne that the film 11 is the positive film above referred to, it having been developed and fixed. A prism or other retracting means represented at 13 is employed. This prism is ofsuch degree that when in the full line position illustrated, and with an image space It (of the positive) in the exposure opening of the film gate, the image will be projected and appear at R upon the screen 16 (See Fig. 3). The exposure is then interrupted, the positive film shifted or fed one image space to move an image L into the exposure opening of the film gate,-and the prism 13 is moved to the dotted line position. Exposure then takes place and the image L will be projected and appear upon the screen The cycle is successively repeated so that images R and L will alternately be shown upon the screen and due to persistence of vision stereoscopic pictures will result. In other words a stereoscopic, cinematographic picture will appear to those viewing the screen 16, tln'ough any suitable instruments preferably of the type disclosed in my copending application Ser. No. 339,- 012. Obviously the object 0 may be a moving one as well as a stationary one.

I have disclosed above, one method cmbodying my invention and have also broadly and generally disclosed one set of instrumentalities for carrying the method into 'prac tice. I-'shall now describe more specifically one form of camera for exposing the negatives. Before proceeding, it may be stated that. the invention may be practiced with various forms of cinematographic cameras embodying dilfering forms offeed and other mechanisms. Furthermore it is to be understood that I have made no atten'ipt to disclos a camera, complete in all its details but only such parts as are necessary to a proper comprehension of the present invent ion.

Referring to Fig. 4, the camera 20 is shown as comprising a film gatelt), adapted to have passed therethrough a film 11, and a lens 12, all of which-will be recognized in view of the description in connection with Fig. 1. The prism 13, provided in accordance with my invention, will also bercco,fnized. The -amera 20 is shown provided with the usual shutter 21 to control the exposure of the film 11 and to obscure or out oft the light therefrom while the film is ininotion. Of the various types of filn'l-feeding mechanism I have selected for purposes of illustration the well known Genevastop' type which may be described as follows. I

A disk 22 having secured thereto a. pin 24 and cam 23 -is operatively connected by means of bevel gears 25, 26, shaft 27 and bevel gears 28,29 to a shaft 30 to be driven the general shape of a Maltese cross cooperates with the cam 23 and pin 24 to be inlermittently operated thereby in the well known manner. The star wheel 32 is secured to a shaft 31 to which there is also secured one or more feed sprockets 33 having peripheral teeth adapted to enter the marginal perforations of the film to translate or feed the latter. The shutter 21 is shown of the disk type and secured to a shaft 34 having also secured thereto a bevel gear which meshes with and is driven by the gear 29. Means are provided for operating the prism 13 automatically and in proper time relationship with respect to the shutter 21 and the film feeding mechanism. One form of such.

secured to a shaft 38. The latter is adapted to drive a vertical shaft 41, journaled in suitable brackets 42, through bevel gears 39 and 40. The prism 13 is mounted in a frame 43 so connected to the two parts of the shaft 41 that theprism may be caused to assume either the full line or the dotted line position illustrated in Fig. 1. Assuming that the shaft 30 is being actuated continuously, the above described parts are designed to operate substantially as follows.

VVith the parts in the position shown in Fig. 4 the film 11 is stationary, the prism 13 is stationary and in the full line position shown in Fig. 1,'and the shutter 21 is in such position as to expose the negative 11. The shutter 21 next moves to a position obscuring or cutting off the light from the film and, while the light is so cut oil, the feed mechanism operates to move the film one image space in the film gate and the shaft 41 and consequently prisn'i 13 is rotated through 180. The film is then stationary as is also the prism 13, the latter now being in the dotted line position shown in Fig. 1.'

The shutter 21 now moves again to expose the negative and so on. It will be noted that the mechanism illustrated in Fig. 4 accomplishes automatically, simply by rotation of the shaft 30, the series of operations apparatusas is necessary for a proper comprehension of this form of the invention, and additional illustration would constitute surplusage. Thus it will be apparent to those skilled in the art that some suitable form of light source will be employed in the projector and it is unnecessary to illustrate this and other well known auxiliary apparatus. A

- While the machine shown in Fig. 4 is practically operable it is open to some degree of objection in that the devices 13 and 37 to 41. inclusive are operated intermittently and on high speeds the incidental shock or succession of shocks may prove damaging to" the prism 13 as well as tothe parts of the camera proper. To overcome this objection and to effect certain other advantages which will hereinafter appear, I have devised a form of retracting meanswhich may be continuously operated instead of intermittently as in the case of the refracting means 13 shown in Fig. 4. In Fig. 5 I have illustrated one form of such means and means for automatically operating the same in proper time relationship with respect to the shutter and feed mechanism. The instrument-alities illustrated in the last mentioned figure may be employed'in connection with either a cinematographic camera or with a ciucmatographic projecting apparatus and Fig. 5 may therefore be taken as illustrative of both of such applications. However to avoid surplusage in description the latter will be confined, in its detailed consideration, to-the application to a camera. In this form of device the elements 13 and 36 to 43 inclusive would be omitted and replaced by the instrumentalities depicted in Fig. 5.

The shutter shaft 34 (see Fig. 5) is prolonged to project beyond the front wall of the camera 20 and has secured thereto a spur gear 50 which drives a spur gear 5 1,secured to a shaft 52, through an idler gear 53. The shaft 52 has also secured thereto a gear 54 which meshes with and drives both of the relatively large gears 55, 56. The gear 55 is shown rotatably mountedupon a stub shaft 57 and the gear 56 upon a stub shaft 58. The last mentioned stub shaft is shown mounted in a bracket 59, secured to the camera 20, in such manner that the gear 56 may be moved in an axial direction toward -or away from the gear 55, fora purpose which will hereinafter appear. The parts may be held in adjusted position by means of a set screw 60. Of course, the gear 54 will-be of sufiicient width to maintain its drive relationship with respect to the gear 56 in any and all of the various positions of axial adjustment of the latter.

The gears 55, 56, also constitute frames or supports for the refracting means and in the specific form of devices illustrated they are each constructed of a rim, a hub and only two diametrically opposed spokes connecting the rim and hub. Each of the gears or frames 55, 56 carries a corresponding pair of retracting devices 61, 62, 63 and 64 one specific form of which I shall now describe, having reference to Figs. 5 and 6.

The retracting device 61 consists of a sector of a plano-concave lens of glass or other suitable material, the angle between the bounding radial surfaces being substantially 180. In other words the device 61 is'a.

solid generated by rotating the section 61 in Fig. 6 about the axis 57 through 180. The device 62 is a sector of a plane-convex lens of glass or other suitable refractory material, the angle between the bounding radial surfaces being substantially 180".

The shape of the devices 63, 64 will be ap parent upon inspection of Fig. 6 in view of the foregoing description. Preferably the devices 61, 62, 63, 64 should all be of the same diopter. The devices 61, 63 may then be obtained by cutting a plano-concave lens on a plane through its optical axis and the devices 62, 64 may similarly be obtained from a plane-convex lens.

\Vhile the gears 55, 56 rotate through one half rotation about their axes 57 and 58 the retracting devices 62, 63 are in the field of the lens 12.(as shown in full lines in Fig. 6) and when the gears turn through the next half revolution the refracting devices 62, 63 are moved out of the field of the lens 12 and the devices 61, 64 into the said field (as shown in dotted lines in Fig. 6). Comparison of Figs. 1 and 6 will indicate that when the devices 62 and 63 are in the field of the lens 12 the same general result is obtained as is the case with the prism 13 in the full line position. And when the devices 61 and 64 are in the field of the lens 12 the same general result is obtained as is the case with the prism 13 in the dotted line position. Bearing in mind that the instrumentalities shown in Fig. 5 are to be substituted for the elements 13 and 36 to 43 in the machine shown in Fig. 4, the operation of the invention shown in Figs. 5 and 6 may briefly be described as follows.

When the devices 61 to 64 are in the relative position shown in Fig. 5, and in full lines in Fig. 6, the shutter 21 isopen and exposure of the film 11 is taking place, the

cause of the novel shape of the refracting devices. Exposure having 7 been accomplished, the shutter 21 closes and remains closed While the feed mechanism acts to feed the fihn oneimage' space. vAt. or about the same time the devices 62, 63 move out of the field of the lens 12 and the devices 61., 64 move into said'field' Feed movement having been accomplished, the shutter 21 again opens to expose the film, the devices 61, 64 now being in the field of the lens 12. This cycle is repeated until the desired length of The refracting (lev/ices shown in Fig. 6

may assume forms other than those there illustrated. For example these devices may be so constructed that they are of prism shape in cross-seetion, or each a combined lens and prism, or convexo-concave and concavo convex or of the double cone or meniscus-prism type, etc. Some of the more numerous possible modifications are illustrated in Figs. 7 and 8.

Referring to Fig. 7 a description of one of the devices 61, 62, 63, 64 will suffice for all in view of their obvious similarity. The retracting device 62 consists of a solid of glass, or other suitable material, generated by. revolving the section 62 (shown in Fig.

7) about the axis 57 and substantially through 180. The result is such as would be obtained by cutting a right cone (of small altitude as compared to the diameter of its base) upon a plane through the altitude, the device 62 being one of the two halves so obtained.

' The 'refra-cting devices 61*, 62", 63 and 64" shown in Fig. 8 are combined lenses and prisms. Each of these devices is a solid obtained by rotating a corresponding one of sections 61", 62*, 68 and 64" substantially through 180 about the respective axes 57, 57, 58 and 58. It will be noted that the devices 61 and 63 if placed thin edge to thin edge, would form a solid, concave on one face and funnel-shaped (i. e. provided with a conical depression) on the opposite face. The devices 62 and 64 if placed thick edge to thick edge, would form a solid, convex upon one side and cone-shaped upon the other.

The operation of the devices shown in 'Figs. 7 and 8 wlll'be understood in view of the foregoing description in connection with Figs. 1, 4, 5 and 6. So far as use 111 connection with a cinemato ra )hic camera is conin Fig.' 6 may be resorted to with satisfactory results. Where finest results of delineation and minutiae are desired the type shown in Fig. 8 should be employed.

It will be understood that the dimensions of the various refracting devices, such as degree and diopter, have been selected primarily for facility in illustration and the drawings are not intended to be working drawings. In general it may be stated that refracting devices of comparatively large radial dImODSIOIIS 1' (see Flg. 5) are pref-' erable. The degreeor diopter or both, of the refracting devices.may be decreased as the radius '1' increases. Without intending to be restricted to any specific dimensions it may be stated that where devices of the type illustrated in Fig. 8 are utilized they will give satisfactory results where the following dimensions are employed: radius (r) 5 inches, prism -1.0 degrees, lens surfaces 0.25 diopter.

Instead of constructing the retracting devices 61 to 64 in the form of 180 sectors, smaller angle sectors may be employed. Thus in Fig. 9 I have illustrated refracting devices 61 to.64 in the form of quadrants. Of course where sectors other than semicircular ones are employed the gear ratio between shaft 34 and gears 55 and 56' will necessarily be changed in order to preserve the necessary synchronous relationship of parts. Thus the devices 61 to 64 shown in, Fig. 9 would rotate only half as fast as those shown in Fig. 5, assuming the same speed of rotation of shaft 34 in either case.

Referring back to Fig. 2 it will be seen that the images ofthe object O upon the series of image spaces R are laterally displaced with respect to those of the series L. If desirable the successive images (assuming the object to be stationary) may be brought into substantial vertical alignment without impairing the ultimate stereoscopic effect 'by adopting the means diagrammatically indicated in-Fig. 10. In this figure the film 11, lens 12,:1nd refracting devices 61 to 64 will at once be recognized in view of thedescription in connection with Figs. 1, 4, 5'and 7.- A second set of refracting devices 161 to 164 are mounted in and actuated by mechanism such as that show-n in Fig. 5 for the devices 61 to 64* except that the former are preferably rotatcd in a direction opposite to the direction of rotation of the latter though at the same speed. By making the degree of the prisms 161 to 164 the same as that of prisms 61 to 64, and the ratio (7 :(P::1:10;' (4 being the distance between the film and the set of devices 61 to 64 and (P. the distance between the two sets of refracting devices) the successive images, upon the negative film, of a stationary object may be caused substantially to align each time the film 11 is being fed one image space. The prism and mechanism directly supporting the same acquires considerable momentum during each movement and the shock on cessation of each movement would 'p' rove damaging especailly at high speeds of operation. I have (in connection with Figs. 5 et seq.) disclosed a preferred structure by virtue of whichthis objection may be obviated. There are other ways in which this objectionable shock or impact action may be considerably reduced. See for example the arrangement disclosed in Fig.1.

' Here the shaft 41 has secured thereto a substantially cross-shape frame 43 carrying the four equianguarly spaced prisms 13 to 13 arranged as illustrated. The gears 39 and 40' are in this case so propertioned as to cause the shaft 41 to rotate 90'each time the film is being fed oneimage space. The operation of this form of the invention will be understood in view of the description in connection with Fig.1.

It will be obvious that the shocks incident to 90 rotation are materially less than in the case of 180 rotation. Furthermore'it will be understood that the shocks may be further reduced by employing a still larger number of prisms 13*. etc. the gearing 39 and 40 being properl designed in each case.

In accordance wit the provisions. of the patent statutes, I'have herein describedthe principle of operation of my invention, to-

gether with the apparatus. which I now consider to represent the best embodiment thereof, but I desire to have it understood that the apparatus shown is only illustrative and that the invention can be carried'out by other means. Also, while it is designed to use the various features and elements in the combination and relation described, some of these may be altered, others omitted and some of the features of each modifi cation embodied in the others Without interfering with the more general results outlined and the invention extends to such use.

The glasses or other refracting devices forming a part of my invention may be made achromatic if necessary or esirable.

What 1 claim is 1. The combination with a cinematographic device comprising a film gate and intermittent film-feeding mechanism, of movably mounted refracting means optically associated with said film gate, said refracting'means comprising a sector shaped lightretracting device one of thefaces of which 0,

is a portion of the lateral surface of a cone,

and means for continuously actuating said.

refracting means in predetermined. timed relationship with respect to said'film-feeding mechanism.

2. The combination with a cinematographic device comprising a film gate and intermittent film-feeding mechanism, of

movably mounted refractingmeans optically associated with said film gate, said refracting means comprising a sector shaped lightrefracting device, one of the faces of which is a sector of a lens surface and the other a portion of the lateral surface of a cone, and means for continuously actuating said refracting means in predetermined timed relationship with respect to said film-feeding mechanism.

In testimony whereof I hereto afiix my signature.- a I MAXIMILLIAN GIRSDANSKY.

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