Patent Publication Number: US-6711348-B2

Title: Partial pre-exposure of photographic film

Description:
CROSS REFERENCE TO PRIOR COPENDING PROVISIONAL PATENT APPLICATION 
     This application claims the benefit of prior copending Provisional Patent Application Ser. No. 60/174,926 filed Jan. 10, 2000 entitled Partial Pre-Exposure of Photograph Film. This application is also a Divisional of application Ser. No. 09/540,440, filed on Mar. 31, 2000 now U.S. Pat. No. 6,400,910. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention is related to single use cameras and to the use of pre-exposed film in cameras of this type in which a predetermined message can be included in photographs to be subsequently exposed in individual frames of the film. This invention is also related to the alignment of the pre-exposed sections of the film with the film frames to be subsequently exposed. 
     2. Description of the Prior Art 
     A typical user can incorporate multiple images into photographs by using pre-exposed film pre-loaded in a camera of the type in which the entire camera can returned for development without removing the film from the camera. A portion of the film used in these cameras has been pre-exposed so that a title or border, typically containing a separate image and/or text, will be part of each photograph. The remaining portion of each frame on this film is exposed in a single use type camera that includes an insert which prevents re-exposure of the previously exposed image. A camera of this type is shown in U.S. Pat. No. 5,853,795. 
     To pre-expose a stripe or border or portion of the film used in these cameras, an image is typically projected from a master image onto the film negative. The majority of each film frame remains unexposed and forms the area in which the main image will be formed on the composite photograph. U.S. Pat. No. 5,794,087 discloses an apparatus for pre-exposing a latent image on bulk film that is then loaded into a pre-loaded camera of a conventional type. Although the image on a continuous reel can be repetitively transferred to the bulk film, the bulk film must then be loaded into standard film cassettes or into a pre-loaded camera in a low light environment in which the remaining portions of the film strip are not exposed. This approach also employs a continuous border surrounding each frame, thus limiting the area available for exposing the principal image. The pre-exposed image must also be precisely aligned with the lens and the aperture frame in which the pre-exposed film is to be used, if the two exposures are to be properly aligned in the finished photographs. 
     SUMMARY OF THE INVENTION 
     The instant invention is intended to simplify, if not totally eliminate, the alignment problems that must be resolved for prior art multiple exposure photographs. The pre-exposed image of this invention is formed by a contact exposure method, as opposed to a employing a projected image which is more difficult to accurately locate. Furthermore, the film is pre-exposed and then loaded into a film cannister in the same light tight enclosure, so there is no need to protect the larger unexposed portion of the film strip from inadvertent exposure. The pre-exposed film strip generated in accordance with this invention may also not require precise registration in the camera in which it is to be used, if the pre-exposed section is not a discrete single image, and it can be either pre-loaded into a single use type camera or it can be loaded into a camera by the user. 
     A photographic film strip in the form of a length of photographic film has a pre-exposed area and an unexposed area. The pre-exposed area is continuous and extends along one edge of the strip between ends of the strip. The unexposed area is also continuous and has a length suitable for making multiple single exposure frames with adjacent frames being separated by a frame line. Upon development of the film, an image formed by the pre-exposed section of each print will extend between opposite edges of prints formed by individual frames without the need to preregister the film in a camera. The pre-exposure comprises a contact exposure. 
     An apparatus for pre-exposing a first portion of a photographic film strip for subsequent use in a camera in which a remaining portion of the photographic film strip is to be exposed is also disclosed. The apparatus includes a light tight enclosure and a cylindrical drum located in the light tight enclosure. The apparatus also includes a master image disposed on a peripheral rim of the cylindrical drum. The master image has an opaque section and an image section. A light source is located on the interior of the cylindrical drum. An initially unexposed photographic film strip is held in registry with the master image, with the first portion in registry with the image section of the master image and with the remaining portion of the photographic film strip in registry with at least part of the opaque section of the master image. The light source can be activated to expose the first portion of the photographic film strip, between its opposite ends, in a single flash. 
     One process for fabricating a photographic film strip having a pre-exposed first section and an unexposed second section starts with the step of fabricating a master film strip by successively exposing a portion adjacent one edge of the film strip to a first image through a frame aperture having one area with a width greater than the width of a frame to be exposed in the camera. A pre-exposed first portion therefore has a length greater than the width of the frame. The master film strip is then positioned in contact with the photograph film strip with an emulsion side of each film strip contacting an emulsion side of the other film strip. Only the portion of the photographic film strip in contact with the pre-exposed first portion of the master film strip along one edge is exposed so that the pre-exposed first section will extend laterally beyond opposite edges of each frame to be formed on the photograph film strip. Then it will not be necessary to precisely position the photographic film strip when it is loaded into the camera. 
     A partially exposed photographic film of this type can be used in either a pre-assembled camera—film package and in a camera that is loaded by the user. One such camera includes a shiftable partition located adjacent one edge of a film frame aperture. The shiftable partition is movable between a first and a second position. When the shiftable partition is in the first position, the film frame aperture is completely open. When the shiftable partition is in the second position, a portion of the film frame aperture along the one edge is blocked to prevent exposure of film behind the shiftable partition. This camera can be used with a standard unexposed film strip when the shiftable partition is in the first position. The same camera can be used with a partially pre-exposed film strip when the shiftable partition is in the second position. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a view of a fully exposed photographic negative film strip having continuous pre-exposed section along one edge and a second area for a plurality of subsequently exposed frames. 
     FIG. 2 is a view of a section of a master film strip negative, having a pre-exposed section along one edge, that is used for partially exposing film strip on which a plurality of frames will be subsequently exposed. 
     FIG. 3 is an enlarged view of a section of the film strip shown in FIG. 2 showing two adjacent exposed frames. 
     FIGS. 4A and 4B are views of the photographs formed by the two negative exposures shown in FIG. 3 in which alignment between a pre-exposed banner along one edge and the frame differs slightly in the two photographs made from adjacent negatives. 
     FIG. 5 is a view showing how a camera and a film recorder can be used to made a master film strip such as that shown in FIG.  1 . 
     FIG. 6 is a view of the film frame plate of the camera in FIG. 5 that includes laterally extending openings that allow exposure of a continuous strip on the master image film strip. 
     FIGS. 7A-7E are views of a light tight exposure assembly in which film strips housed in film canisters can be pre-exposed along one edge by a single flash. FIG. 7A is a side view of a rotatable cylindrical drum on which a film master is mounted. FIG. 7B is an end view of the light tight enclosure. FIG. 7C is a side view showing the interior components. FIG. 7D is a view of a translucent diffusion band used to diffuse the light from the flash unit located at the center of the cylindrical drum. FIG. 7E is an exploded view showing the relative positions of the cylindrical drum, the master image film and the film to be pre-exposed. 
     FIG. 8 is a view of a single use camera that includes an insertable partition that permits use of the camera with either a standard unexposed roll of film or alternatively with a strip of film having a pre-exposed strip along one edge. 
     FIGS. 9A and 9B are views of the manner in which shiftable partition can alternatively close a portion of a film frame aperture to cover a pre-exposed section of a film strip along one edge. 
     FIG. 9C shows the shiftable partition in its open position and 
     FIG. 9D shows the shiftable partition moved to partially close the film frame aperture. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     FIG. 1 is a view of a pre-exposed film strip  2  showing a pre-exposed area or portion  8  extending along one edge  14  of the film strip  2 . For purposes of clarity, this pre-exposed area or portion  8  is shown as a fully developed image, although it should be understood that the pre-exposed area  8  would normally only be developed after the remaining portion of the film strip  2  has been exposed to create a series of photographs or frames containing both images. A common use of a film strip  2  containing separately exposed images of this type is for the pre-exposed area  8  to include a title or caption that will be incorporated into each separate photograph when the film is developed. As shown in FIG. 1, this pre-exposed portion  8  of the film strip  2  comprises a continuous stripe or banner  8  extending along one edge  14  of the film strip adjacent one of the rows of sprocket holes  18  in the film. This pre-exposed stripe or banner  8  will extend substantially between opposite ends of the film strip  2  and is not separated into distinct frames. In other words, this pre-exposed portion  8  of the film  2  is not separated by frame lines which would define the edges of separate photographs on the photographic film strip. Although not shown, this pre-exposed portion  8  of the film strip need not extend completely to the film leader  30  or the trailing end  28  of the film engaging a spool in a film cannister  24  in which the film strip  2  will be located. Since these areas at the opposite ends of the photographic film strip will not include photograph frames, there is no need for the pre-exposed areas to extend into these remote areas of the film strip. It should be understood, however, that this pre-exposed stripe or banner  8  could extend into these areas at either end of the strip of film. Although the embodiment shown herein shows the pre-exposed area  8  along only the lower edge  14  of the film  2 , a similar continuous pre-exposed stripe could be located along the top edge  16  or along both the upper and lower edges of the photographic film strip. Although it would be somewhat limiting with respect to the broader aspects of this invention, the pre-exposed area  8  could be in the form of a border extending completely around the frame area. Further discussion will, however, show that a surrounding border of this type can limit the use of such a pre-exposed strip to only a few of the applications that are otherwise suitable for a pre-exposed film  2  with a continuous pre-exposed banner or stripe  8  located only along one or both of the top or bottom edges of the film strip  2 . 
     FIG. 2 shows a master image film strip  32  that is used to fabricate the pre-exposed photographic film  2  shown in FIG.  1 . The film strip  32  shown in FIG. 2 is a positive. Only those areas  36  that are to be pre-exposed to form the film strip shown in FIG. 1 are translucent and will transmit light when the master image shown in FIG. 2 is used to form a contact image on the film strip  2  shown in FIG.  1 . This pre-exposed contact print image will be formed by placing the emulsion side  38  of the master image film strip  32  in contact with the emulsion side  4  of the photographic film  2  on which the image is to be formed. See FIG.  7 E. By placing the two film strips in registry, with corresponding sprocket holes in each film strip in alignment, the continuous master image on the master image film strip  32  will be transmitted to the pre-exposed area  8  of the photographic film strip  2  as represented in FIG.  1 . The section of the master image film strip  32 , that corresponds to the unexposed portion  12  of the photographic film strip  2  shown in FIG. 1, is opaque so that no light can expose the unexposed portion  12  when the two strips are in registration. 
     FIGS. 3 and 4A &amp; B illustrate the complete photographs that can be taken using a pre-exposed film strip  2  as shown in FIG.  1 . FIG. 3 shows a portion of the continuous length of developed images on a continuous film strip, before they are cut into separate photographs. It should be understood that the individual frames would occupy corresponding positions on the negative strip from which these finished photographs would be made. FIG. 3 shows a section of a film strip showing a frame line separating two adjacent photographs. Note that the frame lines  26  extend between the two portions of the film containing the primary images located in those portions  12  of the film strip that were not exposed when the portion  8  along the lower edge was pre-exposed. The frame lines  26 , do not however extend into the continuous pre-exposed stripe or banner  8  extending along the lower edge  14  of the photographs. It is also important to note that the title lines along the lower edges of the photographs shown in FIGS. 4A and 4B are not identical. Since the pre-exposed stripe along the lower edge is a continuous image  10 , it is not necessary to precisely align this banner with the frames or frame lines  26 . By forming this pre-exposed stripe  8  as a repetitious image  10 , the same information can be conveyed regardless of the precise position of the title bar relative to the photographic frame or the final photograph image. In the representative embodiment shown herein, the title bar is shown as a simple repetition  10  of two separate images, a figure image and text image. This simplified image is merely used to illustrate the result that can be achieved. Normally a more complex repetitious image would be incorporated into the pre-exposed portion of the film. Once the master image  32  has been fabricated in this manner, the next step is to transfer that image to multiple photographic film strips in an efficient manner. 
     The continuous master image  32  for pre-exposing a portion  8  of the film to ultimately include separate images can be fabricated by first generating a single image that will be repetitively used to form the continuous section  10  on the master image film strip  32 . This single image can be generated as a computer image in a conventional manner or it can be a photograph. This image can be transferred to the master image film strip by employing a conventional film recorder having a 4×5 aperture which will generate an image with a width of 1.5 inches, larger than a standard 35 mm frame. A 35 mm automatic camera  44  containing the film strip used to generate the master image  32  when mounted in engagement with the film recorder  42  as shown in FIG.  5 . The width of the image generated by the film recorder  42  is chosen so that it is wider than that which would ordinarily be exposed within a frame of a conventional 35 mm camera. In other words, the image generated by the film recorder is wider than the distance between frame lines  26  or the width of an ordinary 35 mm frame. To expose the master image film strip  32  to this wider image, the standard backplate of the automatic camera  44  is replaced by a backplate having notches or lateral extensions  52  on opposite sides of the frame aperture  48 , as shown in FIG.  6 . In other words the frame aperture is enlarged. Alternatively, the width of the entire film frame aperture can also be increased. Thus as the film in the automatic camera is advanced one frame at a time, the pre-exposure image on the master film  32  will be formed by repetitions of the single image. The ends of each pre-exposure frame image will mesh with the adjacent edge of the next image so that a repeating continuous image will be formed along at least one edge of the master image film strip. Since the camera is mounted directly on the film recorder, the image can be precisely transferred to the master. Successive image segments will be precisely aligned and there will be no gaps or offsets between successive segments of the continuous per-exposure image on the master. Simple projection of the image onto the master, as is suggested by the prior art, will result in a jagged or uneven strip which will adversely affect the final dual image photograph. 
     FIGS. 7A-7E show an apparatus  50  for pre-exposing a portion of a photographic film strip  2  that has been loaded in a conventional film cannister  24 . This apparatus permits pre-exposure of only part of the film  2  in the cannister  24  in a light tight environment. The film cannister  24  is first loaded in the light tight enclosure  54  and the film leader  30  is attached on the peripheral rim  58  of a cylindrical drum  56 . A master image strip  32  has been previously mounted on the rim  58  of the cylindrical drum  56 . Rotation of the cylindrical drum  56  causes extraction of the film strip  2  from the film cannister  24 . The emulsion side  38  of the master image film strip  32  faces radially outward on the cylindrical drum  56 , and the emulsion side of the film strip  2  to be pre-exposed is oriented to face inwardly and in contact with the emulsion side  38  of the master image film strip  32 . A light source  74  located in the center of the drum  56  is activated after the film strip  2  is completely extracted and is in registry with the master image film strip  32 . Only a portion of the film strip  2  will be exposed because an opaque section  34  of the master image film strip  32  will mask the remaining portion  12  of the film strip  2 . After a portion of the film strip  2  is pre-exposed in this manner, the cannister spool and the cylindrical drum  56  are rotated in the opposite direction to return the now partially pre-exposed film strip  2  to the film cannister  24 . 
     The cylindrical drum  56  has a width sufficient to receive a 35 mm film strip between opposite edges of its peripheral rim  58 . The diameter of the cylindrical drum  56  is chosen so that the circumference of the drum is sufficient to receive at least a thirty-six exposure 35 mm film strip. The peripheral rim  58  includes a translucent outer diffusion band  60  formed of a nonopaque plastic that will transmit sufficient light to pre-expose a portion of the film strip placed in contact with the emulsion side  38  of the master image film strip  32 . The circumferential surface of the outer diffusion rim is chosen in conjunction with the intensity of the light source  74  so that the pre-exposed portion  8  of the film strip  2  will have an exposure that is approximately midway between exposure limits that would be anticipated when the a user would employ or encounter in making photographs with a camera in which the partially pre-exposed film strip  2  would be used. 
     The master film strip  32  is positioned on this peripheral rim  58  with the emulsion side facing radially outward. One end of the master film strip  32  is secured to the cylindrical drum  56  by two register pins  62  that protrude outwardly from the peripheral rim  58 . The two register pins  58  are located on either side of the peripheral rim  58  to fit within sprocket holes along the edge of the master film strip  32 . The master film strip  32  is positioned so the register pins  62  extend through specific reference sprocket holes in the master film strip. Typically the reference sprocket holes are the eighteenth (18) sprocket holes from one end of the master film strip  32 . A spring loaded clip  64  adjacent to the register pins  62  is employed to hold that end of the master film strip  32  against the cylindrical drum  56 . The opposite end of the master film strip is also clamped to the peripheral rim  58  of the cylindrical drum  56 , and an adjustable stop member is positioned near that end of the master film strip  32  so that it will engage a surface on the outer enclosure  54  to limit rotation of the cylindrical drum  56 . 
     The cylindrical drum  56  is mounted on a spindle  70  in a light tight enclosure or box  54  so that the cylindrical drum  56  can rotate about the spindle  70  within the light tight outer box enclosure  54 . The outer enclosure  54  includes two side walls  53 , a front and a rear wall  59 ,  61  and top and bottom walls  55 ,  57 . One of the side walls  53  can be opened to provide access to the cylindrical drum  56 . Access to the cylindrical drum  56  is also provided by a hinged loading door  63  located on a top wall  59  of the outer enclosure  54 . The loading door  63  pivots outwardly and can be latched to the top wall  59  in the closed position. The master film strip  32  can also be mounted on the cylindrical drum  56  when the loading door  63  is in its open position. The master film strip  32  can be first mounted on the register pins  62  and the opposite end can be attached using separate clips. The cylindrical drum  56  can be rotated to permit the opposite ends of the master film strip  32  to be attached through the open loading door  63 , or one of the side walls  53  can be partially opened so that the master film strip  32  can be mounted on the peripheral rim  58  of the cylindrical drum  56 . 
     A film cannister  24  containing the photographic film strip  2  to be partially pre-exposed can also be loaded through the open loading door  63  at the top of the enclosure box  52 . A film cannister mounting member in the form of a spring loaded rod is located inside the open loading door  63  near the outer periphery of the cylindrical drum  56 . A rotating shaft will engage a spline on the interior of the spool in the film cannister  24 . The film cannister  24  is loaded in the enclosure  54  with the protruding film leader  30  extending toward the register pins  62 . The two register pins  62  are fitted within a preselected pair of sprocket holes  18  so that the film  2  to be partially exposed is in registry with the master image film strip  32  previously mounted on the cylindrical drum  56 . The end of the film leader  30  is positioned beneath the film clip  64  and the outer loading door  63  is then closed. When the drum  56  is rotated through one partial revolution, the film  2  in the film cannister  24  is drawn out and is deployed with the emulsion side of the film  2  to be partially exposed positioned in contact with the corresponding emulsion side  38  of the master image film strip  32  so that a contact print can be formed. Before the cylindrical drum  56  is rotated, the loading door  63  is closed and film follower wheels  65  on the inside of the loading door  63  engage the film  2  between the cannister  24  and the register pins  62  so that the film  2  from the cannister  24  is smoothly placed along the circumference of the cylindrical drum peripheral rim  58 . 
     When the film  2  has been completely drawn from the film cannister  24  by rotation of the cylindrical drum  56 , a light source  74  located at the center of the cylindrical drum  56  is activated to partially expose the film  2  positioned in contact with and along the outer emulsion surface  38  of the master image film strip  32 . Since a section  34  of the master image film strip  32  is opaque, the portion  12  of the outer film strip  2  in contact with that opaque section  34  will not be exposed when this light source  74  is activated. The image on the image section  36  of the master image film strip  32  is transferred to the corresponding portion  8  of the film strip  2  being partially exposed. After partial exposure of the film  2 , the cylindrical drum  56  and the spool in the film cannister  24  are rotated in the opposite direction so that the now partially exposed film  2  can be returned to the film cannister  24 . The film cannister  24 , which is also light tight, can now be removed from the light tight box enclosure  54 . 
     An electronic flash unit  76  is used to provide the light source  74  for partially exposing the film  2  extracted from the film cannister  24 . The conventional electronic flash unit  76  is mounted in a flash housing  78  on one side of the outer enclosure  54 . Although the flash unit  76  is located to the side of the cylindrical drum  56 , that adjoining side face of the cylindrical drum  56  is open. Inner translucent bands  72  can be added around the drum spindle  70  to further diffuse the light from the electronic flash unit  76 . Two semi-cylindrical bands  72 A,  72 B will encircle the central cylindrical cavity from which the light source  74  emanates to form one inner diffusion band  72 . Multiple layers of inner diffusion bands  72  can be added if necessary or the relative transparency of these inner diffusion bands  72  can be varied to achieve the proper exposure. If the outer diffusion surface  60  on the peripheral rim provides adequate light diffusion, the inner bands  72  will not be needed. 
     Rotation is imparted to the cylindrical drum  56  and the film cannister  24  by an electric motor  90  that drives an upper pulley  86  and a lower pulley  82 . The upper pulley  86  is located in an upper transfer unit  84  and rotation of this upper pulley shaft imparts rotation to the spool of the film cannister  24 . The lower transfer unit  80  is located in the center of one side of the box enclosure  54  so that the lower pulley shaft drives the cylindrical drum  56 . Conventional belts (not shown) connect the electric motor to the pulley shafts. A counter weight is located on the cylindrical drum  56  so that uneven loads are not placed on the electric motor  90 , and rotation of the drum  56  will be smooth. 
     This film exposure apparatus  50  is especially adapted for partially exposing film strips  2  as part of a moderate or intermediate size run. Film in standard canisters  24  can be used, and no special handling is necessary because the film  2  is enclosed in the light tight box enclosure  54  during exposure and is located in the light tight film cannister  24  as the film is loaded into and unloaded from the film exposure apparatus  50 . 
     FIG. 8 shows a standard pre-loaded single use or preloaded camera  96  in which a pre-exposed photographic film strip  2  would be used. A film cannister  24  containing the pre-exposed film would be loaded in this pre-loaded camera  96 . The pre-exposed film  2  would not be loaded by the end user, but would be loaded by the supplier of the pre-loaded camera  96 . After the entire roll of film is developed, the entire camera  96  is then returned to the manufacturer who removes the film from the camera and develops the film containing the two separate images in each photograph. Normally the photographic film strip would be loaded so that the pre-exposed image would be aligned with each frame. However, since the image  10  of the present invention is continuous and is therefore wider than the frame, it is not necessary to precisely align the pre-exposed image with the frame. A portion of the repetitive image will still appear in the final photograph. Since the image is repetitive, it is not important that the pre-exposed image be exactly the same in every photograph. Therefore in addition to employing the pre-exposed film only with factory manufactured pre-loaded cameras, the pre-exposed film of this invention can be sold separately and the film can be loaded and developed by the end user. However, as with prior art pre-loaded cameras of this type, an insert  98  would be added along the top or bottom of the film frame aperture to block the pre-exposed portion of the film and to prevent double exposure. 
     A 35 mm camera  100  into which a standard film cannister  24  including either partially pre-exposed film  2  or a film strip that has not been previously pre-exposed is shown in FIGS. 9A-9D. This camera does not require insertion of a lose piece insert  98  to block a second exposure of the pre-exposed portion  8  of the film  2 . This camera includes a shiftable partition  102  that can be moved between two positions. In a retracted position, the entire film aperture  104  is open so that a film strip  2  and film frames can be completely exposed in a conventional manner. When the shiftable partition  102  is moved to an extended position, a portion of the film frame aperture  104  along one edge will be covered or blocked so that a pre-exposed portion  8 , extending along one edge of photographic film strip, will not be exposed when the camera shutter is open. Unlike prior art single use or preloaded cameras, the film is exposed as it is pulled out of the film cannister  24  in a cannister cavity  108 , that is located on one side of the lens  106  onto a take-up spool, located in a take up cavity  110 , that is located on the opposite side of the lens  106  and the film frame aperture  104 . In other words the film cannister  24  and the film  2  can be loaded in a conventional fashion instead of preloading a spool as for prior art single use cameras. 
     An alternate approach for making a limited number of film strips with a continuous image would not require the cylindrical drum. In this approach only a single pre-exposure image frame is used. This image has a width that is greater than the width of a standard frame. An automatic camera having a back plate forming an enlarged film frame aperture, substantially the same as that shown in FIG. 6 can then be used to sequentially expose the repetitious continuous image, from one single image, onto the film strip which would then be used to take dual exposures of the type shown in FIGS. 4A and 4B. The representative embodiment of this invention can therefore be replaced by other embodiments including slightly different components that would be apparent to one of ordinary skill in the art. Therefore the invention represented by the disclosed embodiment is defined by the following claims and is not limited to the precise structure depicted herein.