Note: Descriptions are shown in the official language in which they were submitted.
~ 1075054
VIEWING IN_T~UI`1ENT
BACKGROUND
The invention relates to an instrument for the one-by-
one viewing of pictures arrayed successively on a transpar-
ent film strip, having a housing in which there is provideda viewing window and, in the light-ray path between the
viewing window and the object, a lens system which magnifies
the viewing angle, and having means for holding and guiding
the film strlp in a viewing plane.
Instruments of this kind are known for the stereoscopic
viewing of still pictures. They are constructed much like
field-glasses, independent light-ray paths and different
transparent pictures being associated with each of the two
viewing windows. The transparent pictures, or diapositives,
are disposed opposite one another in pairs on a rotary disk.
The two simultaneously viewed diapositives produce the
stereoscopic effect. This instrument offers the desirable
possibility of binocular viewing, but it is very limited
in the number of pictures that can be viewed in a continuous
series on account of the necessarily circular configuration
of the picture carrier. The fact that two frames must be
provided on the picture carrier for each picture imposes
an additional limitation upon the number of pictures in a
sequence.
.
--2--
i ~
_
~ ,
,. - . ' ' : : '
10750S4
THE INVENTION
The invention sets out from the consideratlon that
the principle of binocular viewing of still pictures illu-
minated by an outside source will be broadly useful onlyif a great series of pictures can be viewed successively
and without the nuisance of changing picture carriers,
because in the case of a short series of pictures, and
hence a sequence of small informational content~ a viewing
instrument of this kind--if one disregards the stereoscopic
effect--is ùnnecessary~ since comparable information can
also be contained on a directly readable information ve-
hicle.
.
It is therefore the object of the invention to make
available a picture viewing instrument of the kind described
- - in the beginning, which will be inexpensive to manufacture
- and easy to operate, while permitting the continuous view-
ing of a very great number of individual pictures disposed
on a picture carrier.
.~ ' ',
For the achievement of this object, it is proposed in
accordance with the invention that the light-ray paths or
optical axes associated with-the two viewing windows be
brought together approximately in the center of a commonpic-
- tùre aperture located in the viewing plane, and that the
film guiding and holding means have a back support to sup-
--3--
` -
1075054
port the film stri~ durin~ the fil~-driving en~aeement Or
a ~art Or an extern~lly operated mechanical transport means.
The focusing to~ether Or the optical axes for binocular
viewin~ of a frame is known in binocular microscopes. The
complex prism systems used therein for beam splitting, how-
ever, would make the instrument i~practical for economic
reasons for the viewing of large series of pictures. The
apparatus of the kind that is involved here serves for the
purpose of making the picture information on a film strlp
serving as the picture carrier accessible to the user,
doing so in such a manner as to provide him with the com-
fort and convenience ofrered by binocular viewing. The
instrument must therefore be extremely inexpensive~-to manu-
facture, by being made of plastic parts for example, and
must make use Or film cassettes so as to avoid complex film
threading operations.
Thus the present invention provides an instrument for
the individual viewing of pictures disposed successively on
- a transparent film strip, comprising: a housing, a binocular
viewing window in said housing, a picture aperture, a lens
system enlarging the viewing angle and located in the ray
path between said viewing window and an object, holding
and guiding means holding the film strip in a viewing plane,
the optical axes associated with said binocular viewing window
being brought together approximately in the center of said
picture aperture lying in said viewing plane, said strip
guilding and holding means having a back support for supporting
the film strip, and means for moving the film strip when on
said support.
~ -4-
~ l\
~075054
In a preferred embodiment the invention provides
such an instrument in combination with a film strip cassette,
having a wall defining the viewing place, comprising: means
on the outside of said housing in the vicinity of the
picture aperture for the releasable mounting of the film
strip cassette, said back support being formed on said wall,
said wall having a transparent aperture forming the picture
aperture and being aligned with the object.
In certain aspects the invention is developed by pro-
- 10 viding on the outside Or the housing, adjacent the picture
window. a socket or slot for the insertion of a film strip
casse, by forming the back support of the guiding and hold-
ing means on a wall Or the cassette which defines the view-~
ing plane, and by providing the cassette wall defining the ¦-
viewing plane with an aperture which is in line with the
object and forms a picture aperture. Preferably, the socket
or slot has guiding ribs and/or grooves to mate with cor- ¦
responding grooves and/or ribs formed on the outside Or the
~',
~.1
-4A-
;
1075054
cassette, and a resilient detent means for locking the cas-
sette in its proper position in front of the housing aper-
ture.
In a desirable embodiment of the invention, the film
strip has a series of perforations parallel with the series
of pictures, and is in the form of an endless band; a maga-
zine is provided in the cassette and has a height corre-
sponding approximately to the width of the film strip, and
the guiding and holding means is so constructed that the
film strip intersects the light beam only at the picture ap-
erture which is offset from the magazine. In this embodi-
ment the light beam passes through the picture aperture
alongside and approximately parallel to the flat side of
the magazine, and one of the narrow sides of the magazine
is extended laterally to form the film gate provided with
the picture aperture. The film strip, which can be of the
super-8 format, for example, is drawn by the film transport
from the magazine, fed frame by frame past the picture ap-
erture, and from there back into the magazine. At the end --
~of the series of pictures, the beginning of the film series
will again appear before the picture aperture, without the
need for rewinding.
To prevent damage to the film strip~ especially when
the cassette is replaced, a film gate with the picture aper-
ture is disposed within the cassette, and the holding and
`~ .
--5--
.
.
` ~ --
107505~
gulding means is so constructed that the film strip is
guided within the cassette. The light-ray path from the
light source to the two viewing windows must be free and
open through the picture aperture ~ust as in the other em-
bodiments of the invention.
In an alternative embodiment, the picture aperture is
created in a bridge-like part of a cassette, which ~oins
together two spool chambers each of which contains one end
of the film wound within it. In the cassette, which is
attached at right angles to the plane of the eyes, as a
rule~ for reasons of photographic technology, a film strip
having two parallei picture tracks can be used in this em-
bodiment to increase the information content in the picture
carrier, in the manner~ for example~-of the known double-
eight continuous picture film. After the one picture track
has been dlsplayed~ the cassette~ which is disposed asym-
metrically in relation to the picture aperture, is rotated
by 180, and then the other picture track can be vlewed
without rewinding.
. ~ .
In further development of the invention, the back sup-
port is formed on a resilient film gate. The resillent film
gate facilltates the engagement of the~moving part of the
transport means as required for the film transport, without
harming the film. In a preferred embodiment, the transport
means is a sprocket or claw mounted in the housing, which
--6--
1075054
engages the film perforations and is brought out of the
housing by means of a shaft disposed approximately parallel
to the plane of the eyes. The shaft can be rotated from
without by means of a knurled knob in order to advance the
film strip by one frame. Within the scope of the invention,
however, pull-down claw systems, as known in motion picture
pro~ectors~ can be used for the stepwise advancement of the
film strip. It is furthermore possible to accomplish the
transport of the film by means of a spindle engaging a take-
10- up spool of the cassette.
.
In an embodiment of particularly simple construction~
the optical axes in the plane Or the eyes merge rectilinearly
from the two viewing windows to the center of the picture
aperture. In this embodiment, each viewing window must be
sufficlently far away from the picture aperture to avoid
having to cro5s the eyes excessively in viewing the picture.
It has been found, however, that~a distance of about-lO to
15 cm between the viewing windows and the viewing plane
; 20 is sufficient for comfortable viewing. The resultant length
of the housing offers the advantage that it is more conve-
nient to operate the transport means at a greater distance
from the eyes.
Alternatively, provision is made for disposing two
totally reflecting mirrors in the lines of sight between
the picture apertures and the two viewing windows. Due
-7-
1075054
to the resultant reflection~ the viewing distance is ln-
creased, the optical axes being able to be even parallel
ln the vicinity of the two viewing windows. The mirror
surfaces can be made at extremely low cost on appropriate
plastic surfaces by vapor coating or by covering with a
reflective film.
- Molded plastic lenses are entirely adequate for the
lens system for the purposes of the invention.
,
,
~ , , .
~ 25
.~ -
.~ '
_8--
1075054
The invention w$11 now be further explained with the
aid of the embodiments represented in the appended draw-
ings wherein:
Fig. 1 is a cross-sectional view taken along the ocular
plane of an embodiment of the viewing instrument
in which the picture carrier is an endless film
strip contained in a cassette;
Fig. 2 is an enlarged partial cross sectional view taken
- along line II-II of Fig. l;
Fig. 3 is a top view taken in the direction III-III of
Fig. 2, and
Fig. ~ is a partial cross sectional view through a film
strip cassette which can be used in another embodi-
ment of the viewing instrument.
The vlewing instrument represented in cross section
in Fig. 1 has a housing 1 with a binocular viewing window
2a-2b~ and a cassette 3 holding and guiding the film strip,
and forming the object ~ of the instrument. The cassette 3
is inserted releasably approximately in the viewing direc-
tion in the embodiment represented, into a front portion of
apparatus 1 which is provided with straddling projections,
ribs 5 formed on the two outer sides of cassette 3 mating
with grooves of corresponding shape on the inner surfaces
of the front projections. The cassette 3 is held in its
-
_9_
.
1075054
proper position before the aperture in the housing by re-
silient clips or catches 7 which engage the guiding ribs 5
when the cassette is in the proper position~ and can be
bent outwardly against their spring bias to release the
cassette.
The housing 1 is preferably injection molded of plastic
and can be composed of two plastic shells assembled together
approximately in the ocular plane. Since the picture in
the picture carrier, which i5 not shown in the drawing~ is
relatively small to increase the information content within
small film strip dimensions, a lens system to enlarge the
viewing angle is needed, which consists in this embodiment
of two convergent lenses 8a and 8b, each fastened at the
viewing windows 2a and 2b~ respectively in the housing.
The lenses 8a and 8b are coordinated w1th the length of
the two corresponding optical axes 9a and 9b such that a
sharp imaging of the plane in which the optical axes 9a
and 9b converge is produced at the corresponding viewing
window 2a and 2b.
The image plane disposed transversely of the ocular
plane (drawing plane of Fig. 1) is, in this embodiment,
- formed at the face 10 of cassette 3 facing the housing 1.
The visible transparency is framed on the viewer's side
by the picture aperture 12 formed in the front face of the
cassette. When the cassette 3 is in the proper position,
' ' '`' .
-10-
1075054
therefore, the picture aperture is aligned with the housing
aperture 6 in the lies of sight 9a~ 9b. The houslng aper-
ture 6 ls preferably large enough to permit an unhampered
viewing of the picture through picture apertures 12 of dif-
ferent formats and positions.
The film strip 11, which in the embodiment shown in
Fig. 1~ is in the form of an endless band and is rolled up
in a magazine 13, is carried past the picture aperture 12
while being guided on both sides by guiding ribs 14~ so
that it moves at right angles to the plane of viewing, within
the interstice between the face 10 of cassets 3 and housing 1.
As best seen in the enlarged view in Fig. 2, a pressure plate
15~ mounted resiliently in the direction of viewing~ is pro-
vided on the housing, which holds the film strip 11 in con-
- - tact wlth the face 10 of the cassette and hence approximately
in the plane of observation. (In Fig. 2~ the cassette 3 is
shown as spaced away from the housing 1 for the sake of
clarity.) The pressure plate 15 is apertured opposite the
:
picture aperture 12 in a manner that is known in film pro-
jectors.
' . :
As best seen in Fig. 3, the film strip ll has a per-
forated margin 16 by which the strip can be advanced with
the aid of the sprocket 17 represented in Figs. 1 and 2 or
with the aid of a pull-down claw system. The sprocket 17
is mounted rotatably in housing 1 on an axis disposed at
-11--
.
- ~ '
-
1075054
right angles to the film transport means. The shaft 18
associated with the sprocket 17 is carried out of the hous-
ing 1 and terminates in a knurled knob 19. By turning the
knurled knob 19 ~oined to sprocket 17 by shaft 18, the film
strip 11 guided past the picture aperture 12 can be advanced
in the direction of the guiding ribs 14. The sprocket 17
has radial teeth 20 disposed at equal angular intervals,
- which pass through the housing wall adjacent the picture
aperture and through the pressure plate 15 which is pro-
vided with an aperture at that point, to engage the per-
forations in the film. The face 10 of the cassette 3 forms
a back support when the drive teeth engage the film and
prevents the film strip from escaping from such engagement.
A shallow recess 21 is formed in the guidance path of film
strip 11 at the point of engagement of the sprocket teeth,
and permits a deep engagement of the teeth 20 to assure
reliable film transport.
In the cassette configuration represented in Fig. 1,
the illumination ray path throughobject chamber ~ is kept
free by disposing the picture aperture in a side chamber -
of the cassette, i.e., a chamber beside the magazine 13.
- This side chamber is open in the direction of a light source
not shown in the drawing (downwardly in Fig. 1) for the
unhampered access of light to the plcture aperture 12. To
increase the light input it is desirable to provide the
inside walls of the side-chamber forming the object chamber
- -12-
1075054
with a light-reflective coating or to make it of light-
colored material. The wall 22 of the side chamber, which
is parallel to the flat sides of the magazine chamber 13,
serves in the present embodiment as the wall which carries
a rib 5. When the cassette 3 is applied unilaterally or
to other walls on the housing 1, the wall 22 can be omitted
in order to increase the access of light to the picture
aperture 12.
~he endless film strip is wound up in a roll in the
magazine 13, emerges from the magazine approximately axially
on the flat side of the cassette facing away from the object
chamber 4, through the opening 30; it is carried past the
picture aperture 12 through the lines of sight 9a and 9b of
the viewing instrument~ and finally it is introduced tan-
gentally back into chamber 13 and wound onto the spool
again.
The film strip 11 can also be completely enclosed and
20 guided within the cassette, in which case the film gate ---
with the picture aperture is formed in the cassette. Such
a film strip arrangement facilitates the changing of the
cassette and prevents film damage by improper handling, since
-the film strip 11 is not accessible from without.
In Fig. 4 there is shown another embodiment of a cas-
sette 23 for a viewing instrument of the kind described.
-13-
1075054
In this embodiment, a film gate is formed in a bridge por-
tion 24 which joins together two spool chambers 25a and 25b.
The film strip 11 is held in front of the picture aperture
27 in the viewing plane by means of resilient hold-downs
26 in the bridge portion. One end of the film is wound in
each of the spool chambers 25a and ?5b. In the cassette-
design represented in Fig. 4, the guides for the insertion
of the cassette into a corresponding opening in housing 1
are best disposed at right angles to the ocular plane of
the instrument. In this manner the object side of the
bridge portion 2~ can be kept fully unobstructed for the
access Or light.
` In the cassette embodiment represented in Fig. 4~ it
is advantageous to use a film strip 11 provided with two
~~ - parallel picture tracks and with perforations on both mar-
- gins. After the one picture track has been viewed through
the picture aperture 27, the cassette 23 is turned 180
about the optical axis, thus bringing the other picture
-20 track into the viewing path so that it can be viewed.
: ~ .
Within the scope of the invention, many variants of-
the above-described embodiments are possible. For example,
a pull-down claw system known in connection with film
transports in pro~ectors or motion picture cameras can be
- used for the film transport. A reduction of the size of
housing 1 can be achieved by doubling the lines of sight 9a
-14_
1075054
and 9b back on one another by means of appropriately disposed
mirrors~ the basic system of the binocular viewing of a
picture being preserved. The picture aperture can be pro-
vided with a transparent plastic or glass pane.
The viewing instrument described permits the direct
viewing of individual pictures of a motion picture film
of the super-8 mm size, for example. Pictures can be taken
with a conventional motion picture camera set for single
frame operation~ and after the film has been developed and -
installed in an appropriate cassette, it can be viewed with
the viewing instrument. When this photographic technique
is used~ the longer dimension of the picture aperture will
be disposed parallel to the ocular plane.
~ ' 15 , ...
~ 20
; '. ' . .
. 30
-15-
