Lens-fitted photographic film package

A lens-fitted photographic film package for steroscopic photography, wherein a plurality of images of the same subject are taken simultaneously through a corresponding number of taking lenses disposed horizontally side by side at a given distance from each other. Behind the respective taking lenses, exposure chambers and exposure frames for defining the respective exposure areas on the film surface are formed. The exposure frames are each gently curved, and a guide surface for supporting the rear surface of the film is curved complementarily to the exposure frames. Pressing members formed in the guide surface press the film against the end surfaces of walls separating the exposure frames, so as to curve the film along the exposure frames. The film is thus wavy, with forwardly concave film portions in the exposure frames alternating with rearwardly concave film portions between the exposure frames. The optical axes of the taking lenses are upwardly or downwardly offset from the center of the film surface, so that the space under or over the exposure frames can be utilized efficiently.

BACKGROUND OF THE INVENTION 
The present invention relates to a lens-fitted photographic film package 
having a package body which is previously loaded with a photographic film 
and in which simple exposure mechanisms are incorporated. The lens-fitted 
photographic film package is hereinafter called simply a film package. The 
present invention relates especially to such a film package for 
stereoscopic photography. 
Stereoscopic photography takes advantage of parallax and convergence of the 
optical axes of the left and right eyes for making a photographic image 
which appears as if it were three-dimensional. As a stereo camera for 
taking such stereoscopic photography, for example, a Nimslo stereo camera 
with four lenses (trademarked "NIMSLO 3D") is known. In the Nimslo stereo 
camera, four taking lenses are disposed horizontally side by side at a 
given distance from each other in the front of the camera body, and four 
picture frames are recorded simultaneously in the area corresponding to 
two full-size frames, whereby the four picture frames of a same subject 
are each approximately half of a 35 mm film frame in size, and have a 
uniform parallax relative to each other according to the given distance 
between the taking lenses. That is, a subject is taken from four slightly 
different points of view during each exposure. By printing a set of four 
picture frames on a photographic paper provided with a transparent 
lenticular sheet, such as is disclosed in U.S. Pat. No. 3,751,258, and by 
using four printing lenses which are optically equivalent to the four 
taking lenses of the stereo camera, a stereoscopic photograph is produced. 
The above-described conventional four-lens type stereoscopic camera is 
large in size and expensive, because four picture frames are to be taken 
simultaneously in an area corresponding to two 35 mm full-size frames with 
the use of a specific exposure mechanism. 
On the other hand, film packages are known worldwide which are previously 
loaded with a film and have simple exposure mechanisms such as a taking 
lens, a shutter, a film advancing mechanism and the like. The film package 
is a kind of single-use throwaway camera that makes it possible to take 
pictures at will without buying or carrying about an expensive and heavy 
camera. A single-use disposable camera must be cheap and light, so the 
film package must also be simple and compact in construction so as to 
minimize the cost and the weight thereof. For this reason, a 
single-element taking lens is incorporated in the film package. 
Recently, the resolving power of taking lens and photographic film has been 
so remarkably improved that such a large (half-size) negative is not 
always necessary for printing a stereoscopic photograph of popular size 
(76 mm.times. 12 mm to 83 mm.times.114 mm). Therefore, it may be possible 
and reasonable to provide a single-use film package that can take 
stereoscopic photographs. For this purpose, it is proposed to record two 
or three picture frames of small size, e.g. 12 mm.times.18 mm, within an 
area corresponding to a 35 mm full-size frame. 
However, in order to record small size frames in such a way, specific 
members such as specific exposure chambers for forming corresponding 
exposure light paths and exposure frames are necessary, which will 
increase the cost of the device. In addition to this, such small size 
frames can increase dead spaces in the film package. Not only is the 
provision of a plurality of taking lenses and a complex exposure mechanism 
for a stereoscopic camera disadvantageous from a standpoint of cost and 
size of the film package, but also the occurrence of dead spaces worsens 
the problem. 
Because film packages of the type described use a single-element lens as 
the taking lens for lowering the cost, it is necessary to prevent picture 
images from being affected by the distortion that is inevitable when an 
optical image formed by a single-element lens is projected on a flat 
surface. To compensate for this distortion, conventional film packages are 
so constructed that the film surface is gently concavely curved in the 
exposure position. 
Also in a stereo camera, it will be understood that a plurality of 
single-element taking lenses disposed horizontally side by side like the 
above-described Nimslo camera will form a plurality of images having 
different distortions if the film surface is planar. If a set of images 
taken at once by a stereo camera have different distortions, since the 
parallax among those images is variable, it is impossible to make a 
stereophotography by printing the set of images onto a photographic paper 
in the form of a lenticular sheet. 
SUMMARY OF THE INVENTION 
In view of the foregoing, one object of the invention is to provide a film 
package that can take a set of pictures from which a stereophotographic 
print using a lenticular sheet can be made. 
Another object of the invention is to provide such a film package at a low 
cost. 
A further object of the invention is to make the stereoscopic film package 
as compact as possible. 
To achieve the above and other objects, the present invention provides a 
film package wherein a plurality of taking lenses are disposed 
horizontally side by side at a given distance from each other, and a 
plurality of exposure frames are disposed behind the taking lenses for 
defining the respective exposure areas through the taking lenses, and 
pressing members for gently pressing a loaded film from its rear side onto 
the exposure frames are disposed on the opposite side of the loaded film 
from boundary portions between the exposure frames so as to curve the film 
surfaces along the film advancing direction, so that the film is concave 
around the center of the respective exposure frames. 
The above construction curves the film surfaces gently so that they are 
forwardly concave along the film advancing direction in the respective 
exposure frames. Therefore, even when the taking lenses are single-element 
taking lenses, the distortion of the respective optical images formed on 
the film surface by the taking lenses is remarkably reduced. 
According to the invention, the optical axes of the taking lenses are 
displaced upward or downward from the center of the loaded film, so that 
the exposure chambers are disposed upward or downward from the center of 
the film package body. In this way, there is provided a blank under or 
over the exposure chambers, in which elements such as electrical units for 
driving a flash can be accommodated, thereby reducing dead spaces in the 
film package. Therefore, the stereoscopic film package of the invention 
can be made compact and small at a low cost.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
FIG. 1 shows the outer appearance of a film package for stereoscopic 
photography according to a first embodiment of the present invention. The 
film package 1 comprises a package body 2 and an outer casing 3 encasing 
the package body 2. In the package body there are provided simple exposure 
mechanisms such as three taking lenses 5 to 7, a viewfinder 8, a release 
button 9, a counter window 10, a film advancing wheel 11, and so forth. 
The outer casing 3 is made of cardboard or the like, is printed thereon 
with decorative patterns and characters, and is formed with openings for 
exposing the exposure mechanisms incorporated in the package body. 
The package body 2 is previously loaded with a 35 mm roll film. As shown in 
FIG. 2, the package body 2 comprises a front cover section 12, a main body 
section 13 and rear cover section 14 each of which is formed as one piece 
of light-tight rigid synthetic resin. The main body section 13 is formed 
with a semi-cylindrical film container chamber 15 and a semi-cylindrical 
film roll chamber 16 on the left and right sides thereof. The film 
container chamber holds a film container 17 with a spool 17a, whereas the 
film roller chamber 16 holds a roll of unexposed film 18, a 35 mm film for 
instance, which has been pulled out in the factory from the film container 
17 and wound into roll of film 18. One end of the film 18 is attached to 
the spool 17a. Between the film container chamber 15 and the film roll 
chamber 16, there is formed an exposure station 19. In the front surface 
19a of the exposure station 19, three exposure apertures 20 to 22 are 
disposed horizontally side by side corresponding to the taking lens 5 to 
7, as is describe in detail below. 
The film advancing wheel 11 with knurling on its periphery is mounted on 
the top of the film container chamber 15 such that a winding shaft 11a of 
the film advancing wheel 11 projects into the film container chamber 15 
and engages with a spool 17a of the film container 17. By rotating the 
film advancing wheel 17, the spool 17a is rotated to wind the film 18 back 
into the film container 17, frame by frame, as the film is progressively 
exposed. While the film 18 is advanced, a sprocket wheel 23 whose teeth 
engage in perforations of the film 18 (FIG. 5) is rotated according to the 
movement of the film 18, so that the advanced length of film 18 is 
detected. The sprocket wheel 23 rotates one revolution for each film 
advance by three pictures frames. One revolution of the sprocket wheel 23 
moves a frame counter disc 24 by one step and, at the same time, actuates 
a self-cocking mechanism 25 to lock the film advancing wheel 17. The 
selfcocking mechanism 25 also sets a shutter actuating lever 26 in its 
cocked position while locking the film advancing wheel 17. 
In front of the exposure apertures 20 to 22, shutter blades 27 and 28 are 
disposed parallel to the front surface 19a of the exposure station 19. The 
shutter blades 27 and 28 are slidable horizontally along the front surface 
of the exposure station 19a. The shutter blades 27 and 28 are each formed 
with three openings 27a, 28a, respectively, and are connected to a 
connecting lever 29 which is urged by a spring 30 to rotate 
counterclockwise. The shutter blades 27 and 28 close the exposure 
apertures 20 to 22 in their rest position. When the release button 9 is 
depressed, the shutter actuating lever 26 is uncocked to hit the 
connecting lever 29, thereby rotating the connecting lever 29 clockwise. 
As the result, the shutter blades 27 and 28 slide in opposite directions 
and superpose the openings 27a and 28a simultaneously on the exposure 
apertures 20 to 22, thereby opening the exposure apertures 20 to 22 for 
the exposure time. 
Forward of the shutter blade 28, a lens board 31 for supporting the taking 
lenses 5 to 7 is mounted. When the front cover section 12 is assembled to 
the main body section 13 after the taking lenses 5 to 7 are fitted into 
the lens board 31, then the taking lenses 5 to 7 are held in a position 
wherein the optical axes 5a to 7a of the taking lenses 5 to 7 coincide 
with the center of the exposure apertures 20 to 22, respectively. The 
taking lenses 5 to 7 are each a single-element lens, and are formed 
integrally as one piece of rigid synthetic resin. Because it is necessary 
to take simultaneously three images of the same subject on the 35 mm film 
18, the size of a picture frame must be small for keeping the film package 
small and compact. In this embodiment, the size of a picture frame is 
about 18 mm.times.12 mm, and three pictures are recorded within an area 
corresponding to a full-size frame (24 mm.times.36 mm) of a 35 mm film. 
But it is possible to define the size of a picture frame 24 mm.times.18 mm 
or other and to record at once three picture frames in an area 
corresponding to one and a half frames of 35 mm film. In any case, because 
of such a small picture frame, the focal length of the taking lenses 5 to 
7 is shorter than that used in conventional film packages, 35 mm for 
instance. The front cover section 12 has at its center a horizontally 
elongated recessed portion 32, in whose recessed surface there are formed 
three openings 33, 34 and 35 for exposing the taking lenses 5 to 7, 
respectively. The recessed portion 32 is provided to adapt the distance 
between the taking lenses and the film surface to the shorter focal 
length. 
Referring to FIG. 4 showing the interior of the exposure station 19, there 
are three exposure chambers 40 to 42, in whose open ends three exposure 
frames 43 to 45 each defining a picture frame are formed. The exposure 
frames 43 to 45 are gently curved along the film transporting direction 
such that the end surfaces of walls 46 to 49 separating the exposure 
chambers 40 to 42 are rearwardly concave, whereas the open end surface of 
the exposure chambers 40 to 42, that is, the areas around the respective 
optical axes 5a to 7a are rearwardly convex. On upper and lower sides of 
the exposure frames 43 to 45, upper and lower film supporting tracks 50 
are provided along the film advancing direction that support both edge 
portions of the film 18 so as to reduce the film tension required to 
transport the film 18, as is shown in FIG. 3, which is a vertical section 
taken along the separating wall 47. It is to be noted that FIGS. 4 and 5 
show a horizontal section of the film package except for the film 
container 17. 
The rear cover section 14 comprises a rear wall 14a and a bottom wall 14b 
arranged to form an approximately L-shape body. The rear wall 14a is 
formed with a look-in window 58 of the viewfinder 8, an opening 59 through 
which the film advancing wheel 11 projects, and a film guide surface 60. 
It is to be noted that the main body section 13 has an opening 57 
corresponding to the look-in window 58 of the rear cover section 14. 
Left and right side portions 60a and 60b of the film guide surface 60 form 
a part of the inner surfaces of the film container chamber 15 and the film 
roll chamber 16, respectively. At the upper and lower regions of the film 
guide surface 60, four pairs of projections 61a, 61b; 62a, 62b; 63a, 63b; 
and 64a, 64b are provided which are so arranged as to face the end 
surfaces of the separating walls 46 to 49, respectively, when the rear 
cover section 14 is assembled to the main body section 13. Between each 
adjacent two of these projection pairs, there are provided curved back-up 
surfaces 66 to 68 which are gently concave complimentarily to the convex 
open end surfaces of the exposure chambers 40 to 42. In this way, when the 
rear cover section 14 is assembled to the main body section 13, there is 
formed a wavy film passageway between the film guide surface 60 and the 
exposure frames 42 to 45. 
The back-up surfaces 66 to 68 contact the base surface of the film 18 
extending between the film roll chamber 16 and the film container chamber 
15, while the projection pairs press the film 18 at both its edge portions 
against the supporting tracks 50 on the end surfaces of the separating 
walls 46 to 49, as is shown in FIG. 3, thereby holding the film 18 in 
cooperation with the supporting tracks 50. 
The middle back-up surface 67 is further formed at its upper portion with a 
slot 69 for receiving the teeth of the sprocket wheel 23, so that the 
sprocket wheel 23 can rotate without interfering with the back-up surface 
67, as is shown in FIG. 5. In view of the fact that the film 18 is under 
tension, especially in the middle exposure chamber 41, positioning of the 
sprocket wheel 23 at the upper portion of the middle film back-up surface 
67 is preferable, because the sprocket wheel 23 presses the film 18 
against the horizontally convexly curved surface 67 and thus helps to 
curve the film 18 along the surface 67. 
By curving the film portions rearwardly so that they are forwardly concave 
in the respective exposure frames 43 to 45, images formed on the 
horizontally curved film surfaces are prevented from having the horizontal 
distortion that would otherwise be produced by the single element taking 
lenses 5 to 7. 
Because not only the supporting tracks 50 but also the projection pairs 
reduce the contact surface of the film 18, the friction during 
transporting the film is reduced, so that the tension during film 
transport will not unduly increase even when following the wavy path shown 
in FIG. 4. Furthermore, as the image recording surface of the film will 
contact neither the back-up surfaces 66 to 68 nor the film supporting 
tracks 50, abrasion of the image recording surface is prevented. 
The rear and front cover sections and the main body section are fitted to 
each other after being loaded with the film 18 in the above-described 
manner. It is preferable to fix these sections together by ultrasonic 
welding or the like, so that the user may not load a new film into the 
film package 1 after taking pictures with using the previously loaded 
film. 
The film package described above is operated as follows: 
Upon depression of the release button 9, the shutter actuating lever 26 
causes the connecting lever 29 to rotate clockwise, so that the shutter 
blades 27 and 28 slide in opposite directions, thereby opening the 
exposure apertures 20 to 22. When the exposure apertures 20 to 22 are 
opened, light from a subject travels through the taking lenses 5 to 7 to 
reach the film 18, so that three latent images of the subject are recorded 
on three portions of the film 18 bounded by the exposure frames 43 to 45. 
The three latent images have a given parallax relative to each other 
according to the given distance between the taking lenses. 
Because the film 18 is curved along the exposure frames 43 to 45, 
horizontal distortion of the optical images formed by the single-element 
taking lenses 5 to 7 is compensated. As a result, the latent images are 
not distorted. 
When all frames have been exposed, the exposed film 18 has been rewound 
into the film container 17. The package is opened in the light to remove 
the film container 17 containing the exposed film and the container 17 is 
then opened in a darkroom and the exposed film 18 is developed to convert 
the latent images into negative images, and a set of three negative images 
of the same subject are superimposed as a composite single image onto a 
photographic paper provided with a transparent lenticular sheet. Upon 
developing the photographic paper with the lenticular sheet, a 
stereoscopic photograph is produced. 
FIG. 6 shows a second embodiment of the invention wherein semi-cylindrical 
grooves 70 and 71 extend vertically between the two adjacent film back-up 
surfaces 66 and 67 on the one hand and 67 and 68 on the other hand, and 
rotatable guide rollers 72 and 73 are mounted in the grooves 70 and 71. 
Each guide roller 72 and 73 comprise a pair of rollers disposed at 
opposite ends of the grooves 70 and 71, connected to each other with a 
shaft. The diameter of the rollers is such that the peripheries of the 
rollers project from the grooves 70 and 71, and press a transported film 
at its upper and lower edge portions onto the facing surfaces of the 
separating walls 47 and 48. As a result, the same effect as the 
above-described projections 62a, 62b and 63a, 63b of the first embodiment 
is achieved by the second embodiment. The second embodiment is even more 
effective for reducing the tension required to wind the film back into the 
film container than is the first embodiment. 
FIGS. 7 to 9 show a third embodiment of the invention wherein also a flash 
unit is incorporated in a film package for stereoscopic photography. The 
same or like parts are designated by the same reference numerals as in the 
first embodiment, so that the description of the same or like parts can be 
omitted. 
In FIG. 7, the film package 1 according to the third embodiment has a light 
emitting member 80 of a flash unit and a charge switch 81 for the flash 
unit which are disposed on the upper and lower right portions of the front 
of the film package, respectively. An outer casing 3 is formed with an 
opening for exposing the light emitting member 80 of the flash unit and a 
slit corresponding to the charge switch 81 for the flash unit. 
FIG. 8 shows the interior of the film package as a section taken in a 
vertical plane including the optical axis 6a of the middle taking lens 6. 
Also in this embodiment, the exposure station 19 is sectioned into three 
exposure chambers corresponding to the three taking lenses 5 to 7. As can 
be seen from FIG. 8, the optical axis 6a is displaced upward from the 
center of the film surface 18, and an exposure frame 44 of a middle 
exposure chamber 41 is so arranged that the center of the exposure frame 
44 coincides with the optical axis 6a. The size of the exposure frame 44 
is, for example, about 18 mm.times.12 mm (which in practice will be 
slightly smaller by the thickness of the separating walls between the 
exposure chambers). A light-trapping frame 41a for preventing flare is 
provided between an exposure aperture 21 and the exposure frame 44. Both 
of the side exposure chambers are constructed in the same way as the 
middle exposure chamber 44. 
Because the exposure chambers are upwardly offset in this way, there is 
provided a rather large space between the exposure chambers and the bottom 
wall 14b of the package body 2. Therefore, it becomes possible to dispose 
in this space a printed circuit board 82 with a flash driving circuit 83 
mounted thereon, a capacitor 84 and a battery 85 for the flash unit. In 
order to receive the capacitor 84 and the battery 85 in a stable fashion, 
a separating plate 13a is provided under the exposure station 19, this 
separating plate being formed integrally with the main body section 13. 
As shown in FIG. 9, the printed circuit board 82 has a pair of printed 
electrodes 86 and 87 on its printed surface. When the charge switch 81 is 
depressed, a not shown metal plate disposed on the inner surface of the 
charge switch 81 contacts both electrodes 86 and 87, thereby electrically 
connecting the electrodes with each other. This short-circuiting of the 
electrodes 86 and 87 activates the flash drive circuit 83 to charge the 
capacitor 84. When the capacitor 84 has been fully charged, an LED 88 
begins to emit light. Openings 89 and 90 for observing the LED 88 are 
formed in the main body and rear cover sections 13 and 14, respectively. A 
rectangular opening 91 formed in the front cover section 12 functions as a 
flash window into which the light emitting member 80 is fitted. 
According to this third embodiment, as in the second embodiment, the 
optical axes of the taking lenses and thus the exposure chambers are 
upwardly offset, and so the space under the exposure chambers can be used 
to receive the necessary elements of the flash unit except the light 
emitting member 80, so that it is unnecessary to position the capacitor 84 
on the opposite side of the film roll chamber 16 from the exposure station 
19. As the result, the length of the package body 2 is reduced, so that 
the film package 1 is made small and compact, and thus the cost of 
material is reduced, which contributes to the production of the film 
package 1 at a low cost. 
Referring now to FIG. 10 showing a fourth embodiment of the invention, a 
film package 100 is further provided with three conversion lenses 101, 102 
and 103 which are held in a lens holder 104. The lens holder 104 is 
pivotally mounted on a recessed surface 105 in the front of the film 
package 100 such that, when the lens holder 104 is turned up to contact 
the upper half of the front surface of the recessed portion 105, the 
optical axes of the conversion lenses 101 to 103 coincide with the optical 
axes of three taking lenses 5 to 7, respectively. Simultaneously, a target 
mark 107 formed integrally with the lens holder 104 is inserted in a 
viewfinder 106. In this condition, the film package 100 functions as a 
telephotography or macro-photography camera. The other structure of this 
embodiment is similar to that of the third embodiment. 
The target mark 107 is bent in a manner as shown in FIG. 10. Thus the free 
end of the target mark 107 can be caught by a fingernail to raise the 
target mark 107. Thereafter, the target mark 107 can be easily held 
between the fingers, so as to swing up the lens holder 104 to position the 
conversion lenses 101 to 103 before the taking lenses 5 to 7. 
Consequently, changing-over between standard photography and tele- or 
macro-photography is very easy. This fourth embodiment thus makes it easy 
to take stereoscopic telephotographs or stereoscopic macro-photographs. 
FIG. 11 shows a part of a photographic film 110, e.g. a 35 mm film, exposed 
by a fifth embodiment of the invention wherein the optical axes of three 
taking lenses are also upwardly offset from the center of the film 
surface. As can be seen, three images of the same subject are recorded 
within a full-size frame area 110a of the film 110. Furthermore, a mark 
"3D" is recorded below the middle image within the area 110a, in order to 
indicate that the three images are to be printed as a single stereoscopic 
photograph. For recording the mark "3D", the exposure chambers are 
enlarged such that the tapered bottom wall thereof extends toward the 
lower edge portion of the film 110, and a light-shielding plate punched 
with a character "3D" is mounted in the lower area of the open end surface 
of the exposure chambers. Therefore, the bottom margin of the exposure 
frame is defined by the top edge of the light-shielding plate. Of course, 
it is possible to define the size of a frame differently if only the 
central image of the frame is upwardly offset from the center of the film 
surface. The other structure is substantially the same as in the above 
embodiments. 
Because the mark "3D" clearly indicates that three negative images are to 
be printed as a single stereoscopic photograph, it becomes easy to 
distinguish the film 110 of the developed stereoscopic film package from 
other films, so that this fifth embodiment contributes to improving the 
efficiency of printing, as well as to preventing mistakes. 
Panoramic picture frames recorded by a panoramic camera which has been sold 
in the U.S.A. and Japan by Eastman Kodak since 1989, cover a narrower area 
of the film than standard frames, as do the picture frames recorded by the 
film package according to the third to fifth embodiments of the present 
invention, but the frames for stereoscopic photography of the present 
invention are easily distinguishable from the Kodak panoramic frames, 
because at least the central one of the frames of these embodiments is 
offset from the center of the film surface. Therefore, there is no 
possibility of misprinting with the present invention. 
The invention has been described in detail with particular reference to 
preferred embodiments, but it will be understood that various 
modifications can be effected within the spirit and scope of the invention 
as claimed in the appended claims. For example, it is possible to displace 
the optical axes of the taking lenses downward from the center of the film 
surface. It may be possible to provide a plural number of taking lenses 
other than three, such as two, four or more taking lenses. Each taking 
lens may be a compound lens instead of a single-element lens. 
Although the film preloaded in the above-described film packages is pulled 
out from the film container and wound in a roll at the factory, and a set 
of exposed frames, e.g. three mini-frames, are rewound into the container 
after each exposure, it may be possible manually to prewind the film from 
the container prior to the first exposure. It is also possible to wind up 
the film by a predetermined length after each exposure by progressively 
pulling it from the container and to rewind it into the container after 
the exposure of all frames, as in conventional cameras. Alternatively, the 
film roll chamber may receive a container containing a roll of film, and 
the exposed film portion can then be wound into another container disposed 
in the film container chamber. 
The film package of the invention may be used not only for stereoscopic 
photography but also to take at once a plurality of photographs of the 
same subject, e.g. for identification cards or the like. Of course, the 
present invention is applicable not only to a film package but also to a 
compact camera or the like.