Stereoscopic picture system

A stereoscopic picture viewing system having pairs of precisely aligned stereoscopic images arranged in rows on image carriers, with at least two pairs of images on each row, and with one image of each pair located between the two images of a different pair. In one embodiment, the image carriers are circular disks, with the image rows extending radially, and preferably having supplementary key indications at the inner radial ends of each row and in the spaces between the outer ends of successive rows. In another embodiment, the image carriers are long strips of wide film, either still film strips or motion picture film, with the image rows extending transversely across the width of the film strip. A cabinet is provided, for holding two identical image carriers in side-by-side relation, with two binocular viewers on the front wall of the cabinet, so that two persons in side-by-side relation may look through the two viewers and see simultaneously the same stereoscopic views as the two carriers are simultaneously moved to bring successive rows of images to viewing position. Either the binocular viewers or the image carriers are shiftable laterally to determine which of the pairs of images in each row will be aligned with and seen through the binocular viewers. In a variation, the cabinet is larger, accommodating a larger number of people for simultaneous viewing, and with provision for adjustment of the height of the viewers to different eye levels and provision for playing sound reproductions into loud speakers close to the ears of each viewing person. Other variations are disclosed, including a small hand-held viewer, and projectors for projecting images from the image carriers through polarizers onto a viewing screen, where the projected images are observed through polarizing spectacles.

BACKGROUND OF THE INVENTION 
This invention relates to a stereoscopic picture system, employing the 
usual pairs of stereoscopically related images arranged either for direct 
viewing or for projection onto a viewing screen. Such systems, considered 
broadly, have been known in the art for many years, but all of the known 
stereoscopic systems are believed to have drawbacks or disadvantages of 
one kind or another. 
An object of the present invention is to provide an improved stereoscopic 
system which overcomes at least some of the drawbacks or disadvantages of 
the prior systems. 
Another object of the invention is the provision of stereoscopic image 
mounting means for grouping the images in a more compact and space-saving 
manner than has been possible in the prior art. 
Another object is the provision of an image mounting system or means of 
enabling the pairs of stereoscopic images to be very precisely aligned 
with respect to each other when mass produced at relatively low cost; so 
that every disk containing transparent sequences may be utilized for (1) 
direct viewing via binocular lenses; and/or (2) via blown-up projections 
on rear screens without eye strain or fatigue that previously has occurred 
from viewing projected stereograms that were not precisely aligned. 
Still another object is the provision of means for mounting stereoscopic 
images in such manner that a series or set of such images may be more 
easily handled and more easily and quickly viewed (either directly or as 
projected onto a screen) than in the prior art arrangements. 
A further object is the provision of a stereoscopic system particularly 
useful in sales promotion of high priced items, and arranged so that a 
pair of viewing persons (e.g., husband and wife) can comfortably and 
simultaneously view and review duplicate realistic three-dimensional 
pictures of a variety of things when making a selection for purchase, as 
for example expensive items of furniture offered by a furniture store, or 
travel scenes from various tours offered by a travel agency, the system 
preferably including means for manually controlling the advance from one 
scene to the next at any time spacing desired by the user, and also 
enabling reverse movement for reviewing a scene previously observed. 
A still further object is the provision of an automatic audio-stereoscopic 
viewing system adapted for viewing by a considerable number of persons, as 
for example eight, sixteen, or more persons seeing either the same or 
different series of changing stereoscopic views from one or another of a 
series of viewing stations or positions arranged along a cabinet, the 
scenes being changed at predetermined time intervals by power drive 
mechanism, such an arrangement being useful both in sales promotion and in 
providing entertainment or instruction. 
Yet another object is the provision of a non-audio stereoscopic "slide 
film" system especially useful in giving instruction to individual 
persons, as for example providing at a modest expense a series of 
stereoscopic illustrations enabling the user to observe repeatedly if 
necessary, successive illustrations of different maneuver, or of a 
difficult assembly step in a complicated piece of machinery. The 
dimensional pictures and captions are seen in a relatively simple and 
inexpensive hand held viewer designed to facilitate pairs of 
stereoscopically related images arranged in lines extending transversely 
or crosswise on a relatively wide strip of film which may be rolled into a 
roll of indefinite lengths, so that a great many pairs of images may be 
placed on the roll, the strip having a width, for example, of about 51/2 
inches. 
A further object is the provision of relatively simple and inexpensive 
forms of projectors for projecting pairs of stereoscopically related 
images by rear projection onto a translucent screen, from images carried 
by a circular mounting disk, in one form of projector according to the 
invention, or from images carried by a wide film strip, according to 
another form of projector according to the invention, together with means 
for selectively determining, in either form of projector, which particular 
pair of stereoscopic images is to be projected from a line containing a 
plurality of pairs of such images. 
In order to fulfil these and other desirable objects, the invention 
encompasses many different features and aspects. Among the noteworthy 
aspects of the invention, the following may be mentioned. 
(a) The physical or mechanical construction of the holders or carriers on 
which the stereoscopic images are placed, regardless of the relative 
positioning of the images. 
(b) The positional relationship of the respective stereo images to each 
other, on the holder or carrier. 
(c) The method and means for placing the stereo images on the carrier with 
such economy of expense as to permit mass production at reasonable cost, 
and yet with sufficient precision of position to avoid eye strain and 
possible headache to the viewer, especially during observation of enlarged 
images projected onto a viewing screen from the images on the carrier. 
(d) The construction of a relatively simple and inexpensive solo viewing 
device for stereoscopic non-audio viewing of successive related pairs of 
stereoscopic images arranged on a rotary disk, particularly such a device 
so constructed as to enable the observer to observe pairs of images from a 
selected one of two different series or groups of images mounted in offset 
relation to each other on the same carrier disk. 
(e) The construction of a manually driven, non-audio viewing device so 
arranged that two different people in side-by-side relation to each other 
(e.g., husband and wife who are prospective customers of an establishment) 
may simultaneously view identical pairs of stereoscopic pictures and 
captions relating to goods or services offered by the establishment, and 
preferably so arranged that a salesman may at the same time be informed of 
the particular picture or scene being viewed at the moment by the 
prospective customers, in order that the salesman may give the customers 
additional oral information or explanation, relating to the things being 
viewed. 
(f) The construction of larger and more elaborate audio-stereo viewing 
devices having a large number of synchronized viewing stations or 
locations, whereby a large number of seated persons, e.g. ten, 30, 50 or 
more, may simultaneously view identical pairs of stereograms, and hear 
related binaural audio presentations. The same stereograms are seen at all 
of the viewing stations and a tape or record playback controls the 
shifting to the following stereogram. 
(g) The construction of stereoscopic picture viewing cabinets so designed 
that binocular viewing eyepieces together with the related image carriers 
are adjustable upwardly and downwardly, to accommodate varying eye levels 
of different heights of persons seated on fixed height seats during the 
viewing. When the stereo sequences are to be viewed by standing persons 
the up and down adjustments are very practical, especially for trade show 
use. 
(h) The construction of an image carrier, either in the form of a disk or 
in the form of a wide strip of film on which stereoscopically related 
pairs of images are placed in such precise aligned relation to each other 
that the images on the carrier may be used either for direct viewing 
through a binocular device without polarizers, or for projection of images 
on to a screen (preferably by rear projection on to a translucent screen) 
where they are viewed by the aid of polarizing spectacles, the precision 
of placement of the stereoscopically related images being sufficiently 
accurate so that even protracted screen viewing will not cause eye strain, 
eye fatigue, or headache. 
Much work has been done for many years in connection with stereoscopic 
pictures and the viewing thereof. Among the prior patents which may be 
considered pertinent to one or more of the aspects of the present 
invention, are the following: 
______________________________________ 
Harlow 1,957,043 May 1, 1934 
Gruber 2,189,285 February 6, 1940 
Brost 2,296,765 September 22, 1942 
Hausherr 2,365,547 December 19, 1944 
Mast 2,487,459 November 8, 1949 
Gruber 2,511,334 June 13, 1950 
Frankel 2,706,429 April 19, 1955 
Perlin 2,758,505 August 14, 1956 
Ratliff 3,850,505 November 26, 1974 
Glass 3,871,757 March 18, 1975 
______________________________________

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
As shown by some of the above mentioned patents, it has been suggested that 
stereoscopic images be mounted on a holder or carrier in the form of a 
disk. However, the prior art arrangements, while very satisfactory for 
some limited purposes, are not really practical from the standpoint of 
commercial use in sales promotion. The number of pairs of images which it 
is possible to place on the carrier disks of the prior art is so limited 
that only a few items could be displayed on any one disk, so that disks 
would have to be changed frequently during the course of a demonstration. 
Also, the prior art arrangements are not suitable for simultaneous viewing 
of duplicate stereoscopic views by two persons, such as husband and wife, 
who may be jointly trying to decide upon a purchase of an expensive item. 
If a practical and efficient system for showing duplicate realistic 
stereoscopic or three-dimensional pictures to two people simultaneously 
were available at moderate cost, it is believed it would be a great boon 
to various commercial organizations such as travel agencies who could thus 
show prospective purchasers realistic pictures of the highlights of 
various different tours in order to interest the viewers in the tours and 
help them in making a selection, or to a furniture store dealing in high 
grade and expensive furniture which might perhaps not be conveniently 
accessible on the display floor but which could be shown to advantage to a 
husband and wife by means of realistic stereoscopic pictures, at least for 
the purpose of making a preliminary tentative selection. 
It is with such purposes in mind that the stereoscopic system of the 
present invention has been developed, going far beyond anything 
contemplated in the prior art so far as known to the present inventor. 
In order to be practical, and to avoid frequent changes of the carriers or 
holders of the stereoscopic images during a particular demonstration or 
sales pitch, the carrier or holder must contain a considerable number of 
pairs of stereoscopic images. According to the present invention this is 
done not only by increasing the diameter of the disk, but by arranging the 
images on the disk in a special and novel way which it is believed has not 
been previously contemplated. 
According to the invention, the stereoscopic images are arranged along 
radial lines on a rotary disk, and with two pairs of stereoscopically 
related images on each radial line. This is a basic departure from the 
customary and widely commercialized arrangement where the right and left 
images are arranged diametrically on opposite sides of the center of 
rotation of the disk, as in the Gruber U.S. Pat. Nos. 2,189,285 and 
2,511,334, and is also a departure from the arrangement shown in the 
present applicant's U.S. Pat. No. 2,365,547 where the right and left 
images are both arranged on the same radial line, on the same side of the 
center of rotation, but where there is only one pair of stereoscopically 
related images on each radial line. 
Referring now to FIGS. 1, 2, and 4, the holder or carrier disk according to 
the present invention comprises a main body of stiff cardboard 31 with a 
central arbor hole 33 and, at some radial distance from this hole, a 
driving pin receiving opening 35 on one side of the arbor hole and a 
cluster of three small holes 36 on the opposite side of the arbor hole. 
Suitably mounted on this cardboard base are the stereoscopic pictures or 
images, arranged as further detailed below. The pictures may be opaque, to 
be viewed by reflected light when illuminated from the front, or 
transparencies, to be viewed when illuminated from the rear as well 
understood in the art of viewing transparencies. If the pictures are 
opaque, the base or cardboard body 31 need not be apertured or cut out 
except for the arbor hole 33 and hole 35. However, when the pictures to be 
viewed are transparencies, which is the more usual case and normally 
preferred, the cardboard is cut away at the areas underlying the picture 
areas, as indicated for example at 37, FIG. 1, and is also cut away at 
other areas 39 known as key areas, as further explained below. Some of 
these key areas are located between the radial strips of picture images, 
near their outer ends, and other key areas are at the inner ends of the 
radial strips of picture areas, as illustrated in FIG. 1. They will be 
further described and explained in connection with the more detailed 
description of the completed disk with reference to FIG. 4. 
On top of the cardboard thus prepared, there is mounted the photographic 
image carrier, preferably in the form of a sheet of opaque paper or 
transparent film as the case may be, indicated at 41. One of the features 
of the present invention is that instead of mounting the picture images as 
individual images on the cardboard disk, or even as individual 
pre-prepared radial strips, the images are all on the single sheet or 
membrane 41 (of paper or film, as the case may be) which is reproduced 
from a very carefully and accurately prepared master sheet, where great 
care has been taken to get the images at exactly the right spacing and 
orientation with respect to each other. It is found that even slight 
errors in spacing of the images of a stereoscopic pair with respect to 
each other, or a slight angular turning of one image relative to its 
sister image of the same pair, may cause eye strain and fatigue in the 
observer, when viewing enlarged pairs of images projected onto a screen 
through polarizing filters and viewed through polarizing spectacles, and 
may lead to headache. 
This is avoided, according to the present invention, by anchoring the 
original photographic images with great care and precision on a single 
master sheet, of glass or other dimensionally stable transparent material. 
These images accurately placed on this master sheet are, for example, 
pictures of size 21/4.times.21/4 inches, or larger, although frames from 
35 mm. film could be used. Then from this master sheet as many full size 
prints or copies as desired by optical projection printing to a reduced 
size, for making up the desired number of the sheets 41 to be placed on 
the cardboard disks 31 to form the completed stereoscopic disks for 
distribution, for example, to furniture stores carrying a particular brand 
of furniture illustrated in the stereoscopic views, or distribution to 
travel agencies representing a particular wholesaler of travel plans who 
prepared the disks for his retail agents, and so on. Thus if sufficient 
care is taken in the initial lay-out of the images when making the master, 
to achieve proper spacing and proper orientation, it is assured that the 
duplicate sheets or films or membranes reproduced from the master will all 
have the images properly aligned relative to each other, avoiding all 
danger of variation of images relative to each other which would be so 
likely to occur if individual images were individually placed and mounted 
on the cardboard base. 
The above described method of producing the image carrying sheet 41 by 
optical projection printing at reduced size from a carefully prepared 
master which includes all the separate images which are to go on the 
entire disk, is a very advantageous method, and is applicable alike to 
production of disks on which the images are transparencies and those on 
which the images are opaque, since the opaque images start initially from 
photographic negatives which are suitable for projection printing onto 
photographic print paper. 
In mass producing the disks, a slightly different procedure is used when 
the image sheet 41 is opaque, than that used when it is transparent. In 
either case, the images are projection printed from the master sheet onto 
the image sheet 41 preferably while the latter is in the form of a square 
sheet of proper dimensions to cover the diameter of the final disk to be 
produced. If disks having a diameter of 21 inches are to be produced, for 
example, then the images are projection printed from the master onto 
square sheets of 21" on each side, the sheets being black and white print 
paper or color print paper for producing opaque disks, or transparent film 
(black and white or color, as desired) for producing transparency disks to 
be viewed in back lighted cabinets or to be viewed by projection. They are 
fully processed (developed, fixed, and dried) before being mounted on the 
cardboard or other base sheet material. 
In the case of the opaque image sheet, the square sheet is then laminated 
to a square sheet of the desired base material, such as cardboard, of the 
same dimensions, which can be a plain unperforated sheet. Then it is 
die-cut in a single operation to the desired circular shape, with the 
desired edge notches, with the central arbor hole 33, with the drive pin 
hole 35, and with the indexing holes 175 if these are desired. In making 
these disks for opaque pictures, it is not necessary to provide the 
rectangular openings 37 nor the key openings 39, 173, and 174, nor the 
cluster of special holes 36. Therefore it is not necessary to do any 
die-cutting of the cardboard base sheet before the image bearing sheet 41 
is laminated to it, as all the die-cutting can be done after the image 
bearing sheet is applied to the cardboard or other base sheet material. If 
a protective overlay sheet is used on top of the image bearing sheet, it 
is applied, of course, before the die-cutting is performed. 
When the disk is to carry transparencies, however, then much of the 
die-cutting must be performed before the image carrying sheet 41 is 
applied to the base sheet. Therefore, a square base sheet is first die-cut 
to provide the rectangular openings 37 through which light will reach the 
stereoscopic transparencies during the viewing or projection operation, 
and also the key openings 39, 173, and 174 must be formed before the image 
sheet 41 is applied. The arbor hole 33, drive pin opening 35, and cluster 
of holes 36 may be formed in the base sheet before the image sheet is 
applied or may be formed later. The same is true of the indexing holes or 
control holes 175 near the edge. 
Then the image sheet 41, in the form of a square piece of transparent film 
(either black and white or color, as desired) with the images already 
printed thereon from the master, is accurately placed on the square base 
sheet. Because they are both square and of the same size, it is easy to 
line up the edges of the two squares (base and film sheet) accurately with 
each other, to produce correct register. When these sheets have been 
laminated to each other, along with any desired protective overlay sheet, 
a final die-cutting operation is performed, to cut the circular peripheral 
edge of the disk, with the edge notches, and to form the holes 175 if they 
were not previously formed in the earlier die-cutting operation. The 
formation of some or all of the holes 33, 35, and 36 may be deferred until 
this final die-cutting operation if desired, thus forming these holes 
simultaneously in the base sheet, the image sheet 41, and the overlay 
sheet, if any. If these holes 33, 35, and 36 are formed in the base sheet 
during the first cutting of the base sheet, before the image sheet 41 is 
applied, then similar holes must be formed in the image sheet 41 (and in 
any overlay sheet) after it is applied to the base, or else the entire 
central section of the image sheet (and overlay sheet, if any) may be cut 
out in one large opening or hole, before it is applied to the base. 
The overlying or protective sheet 45 may be a clear transparent sheet, 
either flexible or preferably of rigid plastic material to give added 
strength and stiffness to the complete disk. In either case, whether 
flexible or rigid, it may be opal or light defusing instead of completely 
clear. Also, the overlying protective sheet may be a duplicate cardboard 
sheet just like the original base sheet to which the image bearing sheet 
41 is first applied, the second or overlying cardboard sheet having the 
same cut-out openings 37, 39, 33, 35, 36, etc. If a second cardboard sheet 
is used, it will serve to strengthen or stiffen the disk and make the 
total assembly somewhat thicker, but will not provide an actual layer or 
film over the images. 
It has been mentioned that cardboard is the preferred material for the base 
sheet, as it is cheap and readily available. However, the base sheet may 
be of plastic sheeting having approximately the same stiffness as 
cardboard, or even stiffer and/or thicker, if desired. 
With regard to the spacing and arrangement of the stereo images, it is 
found that for the educational and commercial applications for which the 
present invention is mainly although not exclusively intended, it is 
desirable that each of the stereoscopic images have a size of about 11/4 
inches square, rather than the much smaller size which has become common 
in hand-held viewers for casual entertainment purposes, and it is also 
desirable that each disk hold about 48 pairs of stereoscopic images to 
provide on a single disk a sufficient number of views to display a 
reasonable selection of merchandise, artifacts, dioramas, habitats, etc., 
without having to change the disk. As already mentioned, the preferred 
construction according to the invention has two pairs of stereoscopic 
images on each radial line, so that if there are to be 48 pairs of images, 
24 radial lines of images will be required, which means that the radial 
lines of images will be at an angular spacing of 15 degrees from each 
other, this angle of 15 degrees being indicated at 47 in FIG. 4. If the 
inner ends of each radial strip of images are very close, practically 
touching the inner ends of the next adjacent radial strips on either side, 
a circle at the inner ends of the radial strips will therefore have a 
circumference of about 30 inches, or let us say a diameter of about 9.6 
inches. Since each of the radial strips of images is 5 inches long (four 
images each 11/4 inches square) it follows that a circle around the outer 
ends of the radial strips of images will have a diameter of about 19.6 
inches, and the disk itself may have a total diameter of, say, 21 inches, 
to allow adequate space for the edge notches mentioned below. 
These dimensions are given as typical examples for a preferred and 
satisfactory construction, and are not intended as critical limitations. 
The size of the image may vary, within the limits, for example, of 1 inch 
square to 11/2 inches square, although the preferred size of 11/4 inches 
has been found most suitable as a happy balance between a size large 
enough to show good detail in the picture and yet small enough to allow a 
desirable number of stereoscopic pairs to be placed on a carrier disk of 
moderate and easily handled size. 
The novel arrangement of the stereoscopic images on the disk is indicated 
in FIG. 4. Starting for example with the radial line which passes through 
the hole 35 for receiving the orienting pin, this radial line has two 
pairs of stereoscopic images or pictures respectively marked, for 
convenience of understanding, as L1, L2, R1, and R2. L1 and R1 are the 
left and right pictures or images, respectively, of the first pair. L2 and 
R2 are the respective left and right images of the second pair. It will be 
noted that one image of another pair is always located between the two 
related images of one pair. That is, the images L1 and R1 of the first 
pair are separated from each other by the image L2 of the second pair, and 
the images L2 and R2 of the second pair are separated from each other by 
the image R1 of the first pair. 
Now the next radial line, counter-clockwise from the first mentioned line, 
contains two more pairs of images, similarly arranged, and here designated 
as L3, L4, R3, and R4. It is seen that here also, the same rule applies, 
each pair of images being separated from each other by one image of a 
different pair. 
The next radial line in a counter-clockwise direction contains the images 
designated L5, L6, R5, and R6, arranged in the same manner already 
mentioned. This arrangement is followed throughout the entire disk. 
The stereoscopic images on other radial lines are similarly arranged, but 
only fragmentarily shown in FIG. 4, because the images on the few radial 
lines that are completely shown will serve adequately to indicate the 
arrangement where the images are not completely shown. The arrangement 
continues around the entire circumference, radial line by radial line, 
until the starting point or initially mentioned radial line is reached. 
The last radial line of images before getting back to the starting line is 
the one with the images marked L47, L48, R47 and R48. 
As already indicated, the exact number of radial lines depends on the 
dimensions chosen for the stereoscopic images and the diameter chosen for 
the disk, and these factors determine the angular spacing of each radial 
line of images from the next radial line. As already mentioned, if there 
are to be 48 pairs of stereoscopic images, which is a convenient size in 
practice, then the angular interval between successive radial lines will 
be 15 degrees, which is the angular spacing shown in FIG. 4. But if only 
40 pairs of stereoscopic images are to be used instead of 48, then only 20 
radial lines are needed, and the angular spacing from each radial line to 
the next would be 18 degrees instead of 15 degrees, thus enabling the 
diameter of the disk to be somewhat smaller, for the same size of 
stereoscopic image. A greater or lesser number of radial lines of pairs of 
images may be used, within the scope of the invention, but in general 
about 40 to 48 pairs of images, arranged on 20 to 24 radial lines, is 
found to be most suitable for purposes of the present invention. 
While the laminated construction, using a transparent protective sheet 45 
as described in connection with FIG. 2, is the preferred construction, it 
is not essential to use such a protective sheet. A modified construction 
as illustrated in FIG. 3, showing a disk having the same cardboard base 31 
to which is applied the same sheet 41 carrying the images, but in this 
modified construction the transparent protective layer is omitted. 
It will be understood, of course, that the designations L1, L2, R1, R2, 
etc., used in the drawings and this description do not actually appear in 
the finished product. They are merely designations used for convenience of 
description, to indicate where the respective images of a stereoscopic 
pair of images are placed on the disk or holder, in accordance with the 
present invention. 
There are many ways in which the disks or image holders described in 
connection with FIGS. 1-4 can be used. One of the features of the present 
invention is to use them in apparatus designed for simultaneous viewing by 
two persons, as for example by a husband and wife who are viewing 
stereoscopic pictures of expensive items of furniture or jewelry or scenes 
from a proposed tour, preparatory to making a decision on purchasing 
articles or taking a tour; or an instructor and a student, simultaneously 
viewing stereoscopic pictures of some article or event about which the 
instructor is teaching the student or about which the instructor is 
conducting an oral examination of the student; or simultaneous viewing of 
stereoscopic pictures by two colleagues, such as two scientists or two 
doctors, who wish to discuss a matter with each other as they examine 
successive views, without the distraction of having to pass a conventional 
stereoscopic viewer back and forth from one person to the other. For such 
uses, an advantageous form of apparatus is that shown in FIGS. 5-8, to 
which reference will now be made. 
An upright body has a casing or housing with a front wall 101, end walls 
103, bottom wall 105, and a top wall 107. An upper portion of the front 
wall is hinged by a piano hinge 109 (FIG. 8) to a stationary lower section 
of the front wall, so that it may be swung forwardly and downwardly to 
obtain easy access to the interior for removal and replacement of the 
image carrying disks. Legs 111 with suitable braces hold the body at a 
suitable elevation for viewing the stereoscopic images through eyepieces 
(further mentioned below) at the eye level of persons seated on suitable 
adjustable seats such as the stools 113 adjustable in height as by means 
of threaded seatposts 115, so that people of different body heights can 
adjust these stools to bring their respective eye levels to the viewing 
eyepieces. 
Within the cabinet or housing are two parallel shafts 121 laterally 
separated from each other and rotatable in conventional bearings, each 
held by any suitable or convenient bracket, the details of which are not 
important for purposes of the present invention. A simple triangular 
bracket 123, resting on and secured to the bottom wall 105 of the cabinet, 
is shown in FIG. 8 as a convenient example. Secured to and rotating with 
each of these shafts 121 is a hub member 125, the front face of which is 
spaced a little rearwardly from the front end of the shaft so that the 
front end of the shaft provides an arbor for projecting through the arbor 
hole 33 of the image carrier or disk 31 to center the disk and give it 
adequate support. The hub member 125 has a square orienting pin 127 
projecting forwardly from it, which enters the square orienting hole 35 of 
the disk 31 when the disk is impaled on the arbor or shaft 121 and moved 
rearwardly to a position flat against the front face of the hub member. Of 
course the disk must be turned one way or the other until the orienting 
hole 35 lines up with the pin 127. 
Duplicate image holders or disks, indicated in general at 31a in FIGS. 5 
and 8, are mounted on the two shafts 121. The two shafts are rotated in 
synchronism, to bring the duplicate sets of stereoscopic images 
simultaneously into viewing position by the two persons using the 
equipment, by any suitable mechanism for rotating both shafts 121 in 
synchronism with each other. For example, there may be a manually operable 
shaft 131 projecting out of the front wall of the housing near the bottom 
thereof and having a manually operable knob 133 by which it may be turned. 
This shaft 131 turns in a conventional bearing 135 fixed to the bottom 
wall, and has two sprockets 137 driving two chains or non-slip belts 139 
which in turn drive sprockets 141 on the respective disk shafts 121. When 
the parts are first assembled, care is taken to orient the hubs 125 on the 
two shafts in the same way, and they will remain properly oriented 
relative to each other because of the non-slip character of the driving 
connections 139 and the sprockets 137 and 141. Therefore it is assured 
that when any particular radial line of images on one disk is opposite the 
viewing eyepieces associated with that disk, the corresponding radial line 
of duplicate images on the duplicate image disk will be opposite the 
viewing eyepieces associated with the other disk. 
If desired, one may rely on a tight frictional fit of the arbor 121 in the 
arbor hole 33 and the orienting pin 127 in the orienting hole 35 for 
keeping each disk in proper position on the hub. However, it is preferred 
to use other means for assuring that the disk will remain on the hub and 
not come loose during rotation. The preferred retaining means is in the 
form of channel members for loosely embracing the peripheral edges of the 
disk, as illustrated in FIG. 8. There is a channel member 145 extending 
horizontally on the bottom wall of the cabinet, in position to receive the 
bottom edge of each disk, and channel members 147 rising from the ends of 
the bottom channel 145, extending upwardly to approximately the same 
elevation as the shafts 121. 
When inserting or removing stereoscopic disks from the housing, the top 
section of the front wall 101 being open on its piano hinge 109, the disks 
can be dropped down into the channels 147 and between the channels each 
disk can be slightly sprung forward so that the lower part of the disk 
will safely pass by the projecting ends of the arbor shaft 121 and 
locating or orienting pin 127. The shaft and the pin project only a 
relatively slight distance forwardly from the plane of the front face of 
the hub 125, so only a very slight amount of springing of the disk is 
necessary. This is most easily accomplished when the hubs are turned (by 
manipulating the knob 133) so that the locating pins 127 are vertically 
above the shaft. 
When the duplicate stereoscopic disks are mounted in the described manner 
on the respective arbor shafts, the stereoscopic images are viewed through 
binocular eyepieces 151 mounted on the front wall 101 of the cabinet or 
housing, these being mounted for limited horizontal movement in a lateral 
direction in short tracks or guideways 153. These binocular eyepieces 
contain lenses of conventional kind. The persons using this equipment 
place their eyes to the eyepieces, as indicated in FIG. 6. By means of the 
lenses in the eyepieces (which may be adjustable for focusing, like the 
adjustment of conventional binoculars, in case the eye sight of the user 
is not perfect) the user sees enlarged images of the matched pair of 
stereoscopic pictures which are aligned with the eyepiece through which he 
is looking. The person sitting next to him will see the same pictures, 
assuming that duplicate stereoscopic disks have been properly mounted on 
the two shafts. 
When the eyepiece 151 is at the righthand end of its track or guideway 153, 
it will be aligned with the right and left images or pictures of what may 
be called the outer ring or group of pictures on the disk. That is, the 
eyes of the observer looking through the eyepiece in this position will 
see the pictures schematically indicated in FIG. 4 at L2 and R2, if this 
particular radial line of pictures is in viewing position, or at L4 and R4 
if the next radial line is in viewing position, and so on. This righthand 
position of the eyepiece is the position illustrated in FIGS. 5, 7, and 8. 
Now if the eyepiece is shifted to the leftward limit of its track or 
guideway 153, the viewer will see the pictures of the inner circle or 
group, such as pictures L1 and R1, or L3 and R3, and so on. It is entirely 
possible, of course, to view both sets of pictures on one radial line 
before moving to the next radial line, then turn the knob 133 to bring the 
next radial line into viewing position and move the eyepieces to view both 
sets of pictures on this radial line, then proceed to the next radial 
line, and so forth. But this is not the preferred way of using the 
equipment. It would involve constant and undesirable movement of the 
eyepieces back and forth. It is preferred, therefore, to arrange the 
pictures on the disk in logical sequence so that all of the pictures of 
one ring (say for example the outer ring or group) will be successively 
viewed, and then when the disks have been turned through a complete 
revolution, the eyepieces are moved only once to the other position and 
all of the pictures of the other ring or group are viewed in succession. 
This preferred method of operation requires only one lateral shifting of 
the eyepieces for each complete revolution of the disk, rather than 
shifting the eyepieces for each separate radial line of the disk. 
The illumination provided will depend upon whether the pictures on the 
disks are transparencies, which must be illuminated from the rear, or are 
opaque pictures, to be illuminated from the front. FIG. 6 shows 
schematically an adjustable light source such as a bulb 157 mounted on a 
bracket 159. If transparencies are used, the light source 157 will be 
behind the disk. If opaque pictures are used, the light source will be in 
front of the disk but out of the line of sight of the eyepiece. 
A feature which is preferred is to have the light extinguished during 
rotation of the disks, and come on again only when the disks reach the 
exact position for viewing. This avoids the eye strain caused by having a 
brightly illuminated picture moving in relatively close proximity to the 
eye of the observer. Preferably the periphery of the disk is notched as at 
161 (FIGS. 1 and 8) opposite each radial line of pictures. A switch 163 
has an operating arm 165 (FIG. 1) provided with a roller 167 (FIGS. 1 and 
8) which rides on the periphery of the disk as it turns, and drops into 
the notches 161 as they successively arrive at the roller. The switch 163 
is wired in series with the light source within the cabinet. The switch is 
so arranged that it is closed when the roller drops into a notch, and is 
open when the roller is not in a notch. In this way, the light 
illuminating the picture is lit only when the picture is in proper 
alignment with the eyepiece, and goes off during the rotary movement to 
bring the next picture to the eyepiece, coming on again when the next 
picture is properly aligned with the eyepiece. 
This arrangement not only saves eye strain, but also provides a visual 
indication to the user, as he turns the knob 133, that he has turned far 
enough to bring the next picture to viewing position. Moreover, in 
addition to the visual indication, there is an indication by the sense of 
feel, since the roller 167 dropping into the notch acts as a resilient 
detent tending to stop the rotation of the disk at the proper point and 
tending to hold the disk at that point, resisting rotation in either 
direction until a substantial degree of force is exerted on the knob 133. 
Another valuable feature of this embodiment of the invention is the 
provision of means so that the third person may be kept informed of 
exactly what pictures are being observed by the two persons sitting side 
by side at the cabinet. Thus, for example, if a husband and wife are 
seated at the cabinet turning the knob to look at successive pictures of 
expensive furniture, the invention provides means whereby a salesman 
standing beside them may inform himself of which pictures are viewing at 
any particular moment, and thus can make appropriate "sales pitch" 
comments to them regarding the articles shown in the pictures they are 
seeing at that moment. 
This is accomplished by providing the disk with what may be called "key" 
indications, and providing the cabinet or housing with an observation 
opening or peephole through which the "key" indication may be seen by the 
salesman or other third person involved, in a way which will not disturb 
or require displacement of the two principal viewers. 
In order to avoid interference with the persons looking through the 
binocular viewers 151, the key observation openings or peepholes are 
located some distance away from the binocular eyepieces 151, and 
preferably vertically above the shafts 121, in the locations 171 and 172. 
These observation openings 171 and 172 may be provided for one or both of 
the disks 31a. If they are provided for only one, it is preferably for 
the left hand disk, so that the third person (e.g., a salesman) can 
conveniently stand to the left of the left hand one of the two people 
seated and looking through the binocular eyepieces, and can observe the 
key indications on the lefthand disk, to see exactly which pictures or 
images the two seated people are observing at the moment. 
These observation openings or peepholes 171 and 172 are located at the 
proper radial distance from the shaft 121 so that they line up with the 
key markings or indications 173 and 174 on the disk, which key markings or 
indications are placed in an outer series or ring 173 in the wedge shaped 
or triangular spaces between successive radial rows of stereoscopic 
images, and in an inner series or ring 174 at the inner ends of the radial 
rows of stereoscopic images, as indicated in FIG. 4. The outer circle of 
key indications 173 is in line with and observed through the observation 
opening 171. The inner circle of key indications 174 is observed through 
the other observation opening 172. 
The indicia marked on these key locations 173 and 174 can be of any desired 
kind that will appraise the observing person with the information desired. 
It may be a non-stereo miniature reproduction of one of the pictures of 
the two related stereoscopic pictures which are at that moment aligned 
with and observed through the eyepieces 151, or it may be a word or words 
which will remind the observer of the subject matter of the stereoscopic 
pictures which are at that moment aligned with the eyepieces 151, or it 
may be simply a number, in which case the observer (if he has not 
memorized the particulars) will refer to a list which he holds in his 
hand, to see what stereoscopic pictures are identified by that number. 
Whatever indicia or reminder information is placed on the "key" area, the 
area is preferably illuminated synchronously with the illumination of the 
stereoscopic pictures. 
In any case, regardless of the character of the key markings or indicia, it 
must be realized that they are offset angularly from the stereoscopic 
pictures or images to which they relate, because the respective 
observation positions 151 and 171-172 are offset angularly from each 
other. Assuming that the observation openings 171, 172 are angularly 
spaced approximately 90 degrees from the binocular eyepieces 151, then the 
key indications 173 and 174 on the disk itself must be similarly spaced 
angularly approximately 90 degrees from the stereoscopic pictures to which 
they relate. But if the stereoscopic pictures are arranged in radial lines 
spaced 15 degrees apart, as in the example shown in FIG. 4, the key 
markings 173 of the outer circle cannot be at 90 degrees exactly, because 
an angle of 90 degrees from any one radial line of stereoscopic pictures 
would be right in the middle of another line of stereoscopic pictures. So 
the angular offset of the peepholes 171 from the stereoscopic observation 
openings, if the radial lines of stereoscopic pictures are 15 degrees 
apart, can be for example, 821/2 degrees, or 971/2 degrees. But the 
angular offset of the other peepholes 172 for observing the inner circle 
of "key" areas 174 can be exactly 90 degrees. Naturally, it must be 
determined in advance just where the key markings are to be placed with 
respect to the stereoscopic pictures to which they refer, and then the 
observation openings 171 and 172 in the front wall of the cabinet must be 
placed in accordance with the angular displacement which has been decided 
upon, for the disks. 
To insure that the two persons using the binocular eyepieces are looking at 
the same stereoscopic pictures, and to avoid the possibility that one 
eyepiece 151 may be in its righthand position while the other is in its 
lefthand position looking at a different picture on the same radial line, 
it is desirable to connect the two eyepieces by a simple mechanical 
linkage so that they both move together. Such a linkage is indicated 
schematically at 181 in FIG. 5. If one of the eyepieces 151 is moved to 
the left, the linkage will carry the other eyepiece to the left with it, 
and vice versa. 
As a further practical refinement, it may be desirable to ensure that a 
third person, using peepholes 171 and 172, sees only the proper key 
indications and does not become confused by seeing the wrong key 
indication. This can be achieved simply by using two separate lights 183 
and 184 for illuminating respectively the outer and inner series of key 
indications, and controlling these lights by two separate switches 185 and 
187, respectively coupled to the linkage 181. When the dual coupled 
binocular lenses are in their right hand position, the switch 185 will 
light the bulbs 183 to illuminate the key indications of the outer series, 
seen through the peepholes 171. Shifting the binocular lenses 151 to their 
left hand position will, via the linkage 181, open the switch 185 and 
close the switch 187 to light up bulbs 184 to illuminate the key 
indications of the inner series seen through the peepholes 172. If desired 
the respective lights may light up and go dark in synchronism with the 
turning of the disk, by being wired in series with the switch 163 
controlled by the edge notches 161. 
It will be noted from FIG. 7 that these cabinets are so constructed that 
they may be placed back to back. This is a convenient arrangement for some 
stores or other establishments, so that one couple may sit on one side of 
the back to back assembly, looking at the stereoscopic disks which have 
been placed in this cabinet, and another couple can sit on the opposite 
side of the assembly, looking at the pictures on other stereoscopic disks 
placed in the other cabinet, while a single salesman moves back and forth 
from one side to the other, looking into the peepholes from time to time 
and making appropriate comments to his potential customers regarding the 
articles seen in the various pictures which they are viewing from time to 
time. This same arrangement is valuable also for instructional purposes, 
where four students may be seated at the two cabinets arranged back to 
back, and a single instructor may move back and forth from one side to the 
other, answering questions and looking in the peepholes to see how far the 
students have progressed in viewing and analyzing a series or sequence of 
instructional stereoscopic pictures. 
The preferred arrangement for enabling the viewer to view selectively 
either one of the two sets or rings of stereoscopic pictures on the disk 
is to have the viewing eyepieces moved radially toward and away from the 
center of the disk, as described in connection with FIGS. 5-8. However, it 
is within the scope of the invention to reverse this arrangement, keeping 
the eyepieces stationary and moving the arbor shaft of each disk laterally 
toward or away from the stationary eyepiece. Such an arrangement will now 
be described with reference to FIGS. 9-11. 
In this modified arrangement, the arbor shaft 201 and its hub 203 and 
locating pin or orienting pin 205 are like the arbor shaft 121 and hub 125 
and pin 127 of the previous embodiment, except that the shaft, instead of 
being mounted in a stationary bearing, is mounted to rotate in a bearing 
at the end of a bell crank lever 211 pivoted at 213 on a fixed bracket 
215. A second and shorter arm 211a of the bell crank lever carries a 
follower roller 217 which rides on the periphery of a cam member 219 which 
has a high portion 219a and a low portion 219b, each occupying 
approximately one half of the circumference, with a transition slope 
between them. This same cam member 219 also has an internal cam portion 
219c which is cylindrical and concentric with the axis of rotation of the 
cam. The cam rotates in a ballbearing 221 on a fixed member 223 which is 
conveniently the rear wall member of the cabinet or housing. 
The shaft 201 carries the above mentioned hub 203 at its forward end, in 
front of the bell crank lever 211 on which it is mounted. The rear end of 
the shaft projects rearwardly beyond the bell crank lever, into the space 
within the cam portion 219c, and this rear end is provided with a wheel 
225 fixed to the shaft. A tension spring 227 having one end connected to 
the bell crank lever 211 and the other end connected to a fixed bracket 
tends to move the bell crank in a clockwise direction on its pivot 213, to 
tend to hold the wheel 225 engaged tightly with the righthand side of the 
cylindrical cam portion 219c. This is the position illustrated in FIG. 9. 
At this time the follower roller 217 is riding on the low portion 219b of 
the peripheral or external cam. Now if the cam is turned so that the 
follower roller rides up the slope and onto the high portion 219a of the 
cam, as in FIG. 10, this will swing the bell crank lever against the 
tension of the spring 227 so that the shaft 201 will be shifted to the 
left from the position shown in FIG. 9 to the position shown in FIG. 10, 
bringing the wheel 225 into engagement with the left edge of the internal 
cam 219c. A high friction or anti-slip coating is preferably provided on 
the internal surface of the cam 219c and the external surface of the wheel 
225, so that whenever the cam turns, it will drive the wheel with it. 
For manual unidirectional turning of the two cams simultaneously, there is 
a shaft 231 (similar to shaft 131) extending out through the front wall of 
the duo viewing cabinet, and a control knob (not shown) similar to the 
knob 133 in the previous manual bidirectional embodiment. This knob drives 
two sprockets 235 that are fixed to the shaft 231, and they actuate two 
transmission members 237 of a suitable non-slip kind, such as notched 
belts, toothed belts, or chains, and these in turn go to sprockets 239 on 
the respective cam members 219. 
For the manual drive the two duplicate disks bearing captions are mounted 
side by side on the two shafts 201, similarly to the mounting of the 
duplicate disks on shafts 121 in the previous embodiment. Persons viewing 
the stereoscopic pictures use the manual knob on the shaft 231 to bring 
successive pictures unidirectionally on successive radial lines into 
alignment with the viewing eye pieces. 
To convert the above described manual, unidirectional procedure to fully 
automatic audio stereoscopic presentations one unidirectional 
"positioning" or stepping motor will drive the two cams and shift the 
pairs of stereo disks. An amplifier, pairs of speakers, and tape playbacks 
will provide sound, and timing to shift the dimensional pictures from 
stage to stage. With both the manual and automatic audio stereo 
arrangements the binocular eye pieces on the front wall of the housings 
are in a fixed position. 
As turning of the shaft 231 is continued, whether manually or by a stepping 
motor, a point is reached where the two follower rollers 217 of the two 
bell cranks simultaneously ride up the slope from the low cam portion 219b 
to the high cam portion 219a, or ride down the slope from the high portion 
to the low portion, as the case may be. In either event, this shifts the 
bell cranks from one position to the other, that is, from the FIG. 9 
position to the FIG. 10 position, or from the FIG. 10 position to the FIG. 
9 position, and thus shifts the shafts 201 laterally. Hence if the outer 
ring or set of stereoscopic pictures was previously aligned with the 
eyepieces, this shift of the shafts 201 will bring the other or inner ring 
or set of stereoscopic pictures opposite the eyepieces, or vice versa. 
Turning of the shaft is continued, and the stereoscopic pictures of the 
second ring or set are successively viewed. The turning of the shafts 201 
and consequent turning of the disks is caused by the driving relation 
between the wheels 225 and the surface of the cam 219c, and the above 
mentioned use of a non-skid or non-slip coating on these parts ensures 
that the two duplicate disks will not get out of phase with each other. 
In some cases a merchant may wish to let his customer see only the 
stereoscopic pictures on the outer ring or set of pictures without seeing 
those on the inner ring or set, or vice versa. In the form of construction 
illustrated in FIGS. 5-8, a simple conventional lock may be provided to 
prevent movement of the viewing eyepieces from one position to the other, 
so that the customer can look at only the particular set or ring of 
pictures determined by the proprietor. In the form of construction 
illustrated in FIGS. 9-11, this may be accomplished by providing a 
lockable and releasable stop mechanism of conventional construction, 
confining the rotation of the cam member 219 to half a revolution, and 
enabling the proprietor to select either half of the revolution he may 
wish, blocking the other half. This does not interfere with full or 
complete revolution of the disk carrying the stereoscopic images, since 
the shafts 201 revolve through two complete revolutions for each single 
revolution of the cam members 219. The diameter of the wheels 225 is one 
half the diameter of the circular cam surface 219c on which they ride. 
Another embodiment of the invention is illustrated in FIGS. 12-18. This 
embodiment is suitable for use either in entertainment or in sales 
promotion, especially in places frequented by the public such as air 
terminals, bus terminals, shopping malls, etc. In this form of the 
invention now to be described, a larger number of viewers (ten in this 
illustrated embodiment) simultaneously see the same stereoscopic pictures 
and hear either recorded music or a recorded talk appropriate to the 
pictures. All of the picture disks are simultaneously rotated 
automatically at timed intervals, and the viewer has no control over the 
sequence or timing. 
In the preferred form of this construction, the cabinet includes two 
upright pedestals 251 carrying illuminated posters or other pictorial 
matter for attracting attention. These pedestals form the ends of the 
structure, and are connected to each other by a bridge-like web including 
longitudinal top and bottom members 253 and 255 respectively. Upright 
partitions 257 extend crosswise between the members 253 and 255. Mounted 
for upward and downward sliding movement between the partitions, on 
suitable guideways or tracks indicated schematically at 259, are the 
box-like units 261, each containing an arbor shaft and hub and locating or 
orienting pin, similar to those elements in FIG. 8. In this case, however, 
the hub is made of larger diameter, a little larger than the diameter of 
the disk which carries the stereoscopic images, and the periphery of the 
hub is provided with teeth 263 (FIG. 17) spaced at the same interval as 
the angular spacing of one radial row of stereoscopic pictures from the 
next radial row. 
For turning the disks to bring successive radial rows of stereoscopic 
pictures in line with the binocular viewing eyepieces, each of these 
mechanism boxes 261 is provided with a pneumatic cylinder 265 having inlet 
and outlet connections 267 and 269, and having a piston rod 271 to which a 
flipper 273 is pivoted at 275. An angular part 277 on the flipper 
overrides the piston rod and limits the extent to which it can turn in a 
clockwise direction on its pivot 275, but does not prevent it from turning 
counter-clockwise on its pivot, as illustrated in broken lines in FIG. 17. 
Assuming that the piston is at the left end of its stroke, now if 
compressed air is admitted through the connection 267, the piston rod will 
be moved to the right, and the lateral pin 279 on the depending portion of 
the flipper or kicker 273 will engage against the radial surface of a 
tooth 263 and will move the hub clockwise through the space of one tooth, 
at which point a resilient detent 281 snaps over a tooth to hold the hub 
against retrograde movement. This resilient detent 281 preferably is 
operatively connected to an electric switch 283 which controls the 
illumination of the pictures on the disk (which can be either front or 
back illumination, depending on whether the pictures are opaque or 
transparencies) in the same manner that the previously described switch 
mechanism 163, 165 turns the illumination off during the movement of the 
disk. In this instance, the dropping of the detent 281 off of the end of 
the tooth with which it was engaged, when the pneumatic cylinder begins to 
turn the hub and disk, turns the light off, and the light comes on again 
when the detent 281 becomes properly seated on the next tooth. 
Each of these mechanism boxes 261 also has, in addition to the hub for 
holding the stereoscopic disk and the pneumatic cylinder arrangement for 
turning the hub, a binocular viewing eyepiece 301, and a pair of earphones 
303 mounted in wings projecting outwardly in position to be in close 
proximity to the sides of the head of a person having his eyes at the 
eyepieces 301. The eyepieces 301 and the wings 305 containing the 
earphones 303 are preferably formed as a unit mounted in a short 
horizontal track on the front wall of the box 261, for lateral horizontal 
movement through a short distance (about an inch and a quarter) so as to 
bring the eyepiece in line, selectively, with either the outer ring of 
stereoscopic pairs of pictures on the disk, or the inner ring of such 
pictures. However, this movement is preferably not under the control of 
the viewer, but is under the control only of the proprietor of the 
establishment, and a lock of any conventional kind is provided for each of 
these laterally movable assemblies, to lock them in the position selected 
by the management, so as to view only the outer ring of pictures on the 
disk, or only the inner ring, as the case may be. 
In one of the end pedestals 251, such as the left hand pedestal viewed in 
FIG. 12, there is a supply cylinder 311 of compressed air, leading through 
conventional timing mechanism of known form (not shown) to flexible hoses 
supplying air to the inlets 267 and 269 of the pneumatic cylinders 265 in 
all of the respective mechanism boxes 261. This automatic timing 
mechanism, at suitable predetermined intervals, supplies compressed air to 
the connections 267 at the rear ends of all of the cylinders 265, 
advancing the piston rods to turn all of the disks in all of the boxes 
through one space, simultaneously exhausting air from the other connection 
267, of course, and shortly therafter the timing mechanism exhausts air 
from each connection 267 and supplies air to each connection 269 to 
retract the pistons back to their starting position, ready for the next 
forward stroke. During this backward movement, the flipper or kicker 273 
swings counter-clockwise on its pivot 275 as indicated in broken lines, so 
as to clear the tooth of the hub, and then when it clears this tooth it 
swings down again to its normal effective position, as illustrated. 
Also in one of the pedestals 251, there is preferably a magnetic tape 
player or phonograph disk player, with amplifier, indicated schematically 
at 321, electrically connected by flexible wiring connections to the 
earphones 303 of all of the separate mechanism boxes or viewing stations. 
Thus each person having his eyes at the binocular viewing eyepieces hears 
the appropriate sounds issuing from the binaural earphones 303 close to 
his ears, so these sounds can be relatively soft and will not be heard at 
a distance from the installation. The sounds can be in the form of a talk 
or lecture or salespitch relating to the pictures being shown 
stereoscopically, or can be in the form of music. 
The mounting of these individual back-to-back mechanism cabinets for upward 
and downward sliding movements, like sliding window sash, is an important 
feature permitting the stereo pictures to be viewed in comfort by people 
of varying heights. Fixed height stools or chairs may be provided as 
illustrated, in which case the seated user will move the binocular lenses 
up or down to their most comfortable viewing location. For many trade show 
programs and other merchandising needs the flexible upward and downward 
feature can be incorporated into clients' display presentations to permit 
prospects to stand while viewing the stereograms. In some cases manual 
shifting of the disks that carry captions will be practical for the 
standees. 
From the plan view shown in FIG. 14, it will be seen that in this 
particular illustrated embodiment, there are five viewing positions on one 
side of the bridge-like structure and five positions on the other side, so 
that ten people at a time can use an installation of this kind. The 
novelty of such an installation is sure to excite interest, in a public 
place, making it likely that people may even wait in line for a viewing 
position to become available, when all are occupied. This would be, for 
example, an excellent way for an airline to show pictures of available air 
tours, at an installation of this kind set up in a waiting room of an air 
terminal. 
With regard to the locking of the shifting movement of the eyepieces so 
that only one set of stereoscopic pictures on the disk can be seen, even 
though two sets of pictures are on the disk, it should be explained that 
this is for the purpose of enabling the program to be varied from time to 
time with the least effort on the part of the management, but of course 
the management can use the apparatus in a different way if desired. 
Assume, for example, that twenty-four different stereoscopic pictures are 
sufficient for a particular desired program, but the disk holds 48 pairs 
of stereoscopic pictures, 24 in an inner ring and 24 in an outer ring. It 
will be easier and less expensive for the management to make up two 
separate programs and place them on the disks at the same time. Then the 
disks are placed in the various mechanism boxes 261 (ten identical disks 
in the ten boxes) and the viewing eyepieces are all placed and locked in 
their righthand positions or lefthand positions as the case may be, 
depending on which program the management wishes to show. The appropriate 
music or talk tape is placed in the sound mechanism 321, and the machine 
is turned on. 
After the program has run for a desired length of time, say for example one 
week, the management may decide to show the other program, already 
provided on the same disks. Because the program is already on the disks, 
it is not necessary at this time to remove the disks from the apparatus, 
but it is only required to unlock the viewing eyepieces and shift each of 
them to their other position and lock them again, this being a very simple 
procedure taking only a few seconds. Then the music or talk tape in the 
sound mechanism 321 is changed to provide sounds appropriate to the new 
program, and the apparatus is ready to go again. This is much simpler than 
if one had to change all of the disks, every time that a program was to be 
changed. 
There may be times when it may be desired to use the disk mounting 
arrangement for ordinary flat or non-stereo pictures. This is indicated in 
FIG. 4 by the use of the letters NS (standing for "non-stereo") followed 
by a number. Since the particular disk illustrated as an example in FIG. 4 
has space for 48 pairs of stereo pictures, there are a total of 96 picture 
areas, and if flat pictures rather than stereo pairs are to be used, it is 
apparent that 96 flat pictures or non-stereo pictures can be placed on the 
disk. These non-stereo indications in FIG. 4 are given merely to show a 
possibility of use of the disk, and they do not represent the preferred 
use thereof. However, for training or instruction purposes, there may be 
times when a larger number of "flat" or non-stereo pictures would be more 
important than a smaller number of stereographic pictures, and then the 
flat or non-stereographic pictures can be mounted on the disk. They are 
preferably viewed by projecting successive individual pictures onto a 
screen (rear projection ordinarily being used) and observing the enlarged 
image on the screen, no polarizing filters or spectacles being needed. 
The non-stereo disks are produced by the same method used in producing 
stereo disks; that is, an accurate master is prepared, preferably of 
somewhat enlarged size with relation to the desired size of the final 
disk. Then the carrier sheets 41 carrying the final images are produced by 
optical projection and reduction from the master, and are mounted on the 
disk bodies 31 of cardboard or other desired base material, and a final 
cover sheet 45 is added if desired, or omitted if preferred, and the final 
die-cutting is performed. The key indications 39, 173, 174 are omitted on 
the "flat" or non-stereo disks. 
The arrangement of stereographic pairs of images on rotary disks is the 
preferred arrangement. However, certain aspects of the invention are 
applicable also to wide strips of film, without the use of a disk. For 
example, referring now to FIG. 19, stereo pairs may be arranged cross-wise 
on a film strip 351 approximately 5 inches wide, containing successive 
rows with two pairs of stereoscopic images on each row. The arrangement 
would be the same as in any one of the radial rows in FIG. 4. That is, 
each row extending crosswise of the film in FIG. 19 contains the left 
image of a first scene, then the left image of a second scene, then the 
right image of the first scene, and then the right image of the second 
scene, just as in FIG. 4. If these images each are about 11/4 inches 
square (the preferred size as described in connection with FIG. 4) then 
they can be accommodated on a film strip five inches wide, or say about 
51/2 inches wide to play safe and leave a little margin at the edges. 
The film may be fed down from a supply roll 353, past a binocular viewing 
eyepiece 355 having provision, such as a lever 357, for interocular 
(interpupillary) adjustment. The eyepiece 355 is mounted for rightward or 
leftward of about 11/4 inches along a track 358 to align the eyepieces 
with the stereoscopic views of the first set (first and third picture 
areas from the left) or with the stereoscopic views of the second set 
(second and fourth from the left). There may also be a focusing adjustment 
359. The transport of the film is accomplished by manually turning the 
knob 361 of the take-up roll 363. 
When all of the film has been fed down, looking at, for example, the first 
set of stereoscopic pictures, then the lenses of the eyepiece are shifted 
laterally by moving them rightwardly along the track 358, and the 
direction of feed of the film is reversed, now using the bottom roll 363 
as the supply roll and operating the knob 365 of the top roll 353 to 
utilize it as the take-up roll, and the stereoscopic pictures of the 
second set are examined successively as the film strip is moved upward 
step by step. Alternatively, the film strip may first be completely 
rewound, and then the second set of stereograms may be viewed while the 
strip is fed downwardly again rather than during the upward rewinding 
movement. 
This is a very simple and inexpensive construction. A simple web 367 has 
forwardly extending arms or brackets to hold the upper and lower spools 
and to support the body 369 on which the binocular eyepiece is mounted. 
This body may contain an electric light for illuminating the film from the 
rear (assuming that the pictures are transparencies) or the rear end of 
the body may be open so that the user holds it toward the light and 
obtains merely natural illumination for the film. 
In FIG. 20 is shown a stereoscopic slide 381 in a mount 383 suitable for 
placement in a stereoscopic projector or a hand viewer. This slide has 
four images, arranged like those on the film strip (FIG. 19) and like 
those on any given radial line of the disk (FIG. 4) so that the two 
companion pictures of one view are separated from each by one of the 
pictures of the other view on the same slide. That is, as explained in 
connection with the disk of FIG. 4, the images L1 and R1 of the first 
stereoscopic scene are separated by the image L2 of the second scene, and 
the two related stereoscopic images L2 and R2 of the second scene are 
separated from each other by the image R1 of the first scene. This 
arrangement results in a great saving of space and economy of material. 
FIG. 21 shows schematically an automatic-audio system for projecting images 
from stereoscopic disks of the kind above described in connection with 
FIGS. 1 and 4. The projector has a rear section 401 and a front section 
403, the rear section containing the usual conventional lamp, reflector, 
and condenser lens, not shown because all of these parts are conventional 
and well known. 
The rear section 401 also contains a conventional step-by-step motor 
mechanism (not shown) having an arbor shaft 405 projecting forwardly with 
its axis parallel to the optical axis of the projector. On this arbor 
shaft is mounted the stereoscopic image disk 407, which may be identical 
with the image disk disclosed in connection with FIGS. 1 and 4. There is a 
hub on the arbor shaft 405, not shown but just behind the disk 407 in FIG. 
21, this hub being similar, for example, to the hub 125 in FIG. 8 except 
that, instead of having the square drive pin 127 of FIG. 8, it has a 
cluster of three drive pins 409 (FIG. 21) which fit into the cluster of 
three holes 36 shown in FIG. 4. As the arbor and hub turn, the cluster of 
pins 409 extending forwardly through the disk served to turn the disk with 
the arbor and hub, bringing one after another of the radial rows of 
stereoscopic images into the beam of light produced by the condenser lens 
of the projector. 
A single drive pin, such as the pin 127 (FIG. 8) engaged in a single hole 
such as the hole 35 (FIG. 4) in the stereoscopic disk would serve to drive 
the disk so far as the mere mechanical drive function is concerned. 
However, for psychological reasons, it is preferred that the projector 
have the three drive pins 409 fitting in the three holes 36 of the disk, 
because the use of three drive pins brings to mind and emphasizes the 
three-dimensional nature of the projector and the three-dimensional 
picture which results from the use of this stereoscopic projector with the 
stereoscopic disk. 
On the front section 403 of the projector there is a laterally extending 
track or guideway 411 along which slides a carrier 413 for the 
conventional projection lenses 415 and 417. These projection lenses are 
conventional except that they are mounted with polarizing filters 419 and 
421, also conventional in themselves, one of which polarizes the projected 
beam of light in a horizontal plane and the other of which polarizes the 
projected beam in a vertical plane, as indicated schematically by the wavy 
lines. The stereoscopic pair of pictures illuminated by the projection 
lamp and condenser lens which happen at the moment to be aligned with the 
projection lenses 415 and 417 are projected by these projection lenses and 
through the polarizing filters onto the rear of the translucent projection 
screen 425, and are observed from the front by persons wearing 
conventional polarizing spectacles indicated schematically at 427. 
When the projection lens carrier 413 is in the position shown in FIG. 21, 
at the left end of its track or guideway 411, the projection lenses 415 
and 417 will be aligned with the outer series or set of stereoscopic 
images on the disk, and will project, for example, pairs of images such as 
L2 and R2 or L4 and R4 in FIG. 1. When the projection lens carrier 413 is 
moved to the right end of its guideway 411, it will then be in position to 
project the inner set or series of stereoscopic pairs, such as L1 and R1, 
L3 and R3, etc. 
The conventional step-by-step motor which turns the arbor 405 and its hub 
one step at a time may be similar to the motors customarily used, for 
example, in step-by-step turning of circular ring type slide magazines in 
still picture slide projectors. Notches or inaudible blurps are 
incorporated into the audio tape cassettes that fit in playback mechanism 
429. These notches or blurps serve to time the shifting of the disks by 
the motor, through conventional circuitry. The playback unit 429 also 
serves to amplify and feed the audio from the cassette tape into 
auditorium type speakers that are conventional and are not shown. 
FIG. 22 shows schematically a projector system for projecting stereoscopic 
images from wide roll film of the kind described in connection with FIG. 
19. The projector body is indicated in general at 501, and contains the 
usual conventional lamp, reflector, and condenser lens. The body carries 
suitable brackets and bearings for supporting two film reels 503 and 505, 
either one of which may be regarded as the film supply reel or spool, and 
the other as the film take-up reel or spool. 
A forward extension 507 on the body has a vertical slot through which the 
film is threaded, and on the front of this body is a laterally extending 
track 511 for supporting the projection lens carrier 513 on which are 
mounted the projection lenses 515 and 517 with their associated polarizing 
filters 519 and 521. 
The action of these parts is substantially the same as that of the parts 
numbered 411 to 421, inclusive, in FIG. 21. When the carrier 513 is at the 
left end of its track 511, it projects the illuminated stereoscopic pairs 
of the left-hand series or set on the strip film 500, such as images L1 
and R1 in FIG. 19. If the projection lens carrier 513 is moved along the 
track 511 to its righthand position, it will then project the illuminated 
images of the righthand set of pairs of stereoscopic images, such as those 
marked L2 and R2 in FIG. 19. The images are projected onto the rear of the 
translucent screen 525, where they are viewed by observers through 
polarizing spectacles 527, just as in the case of FIG. 21. 
Preferably there is one step-by-step motor connected with each of the reels 
503 and 505, or else a single motor connected alternatively to both reels 
through a clutch system, so that by suitable operation of the conventional 
remote control cord or cable shown schematically at 531 the lecturer 
standing by the screen can cause the film to be advance step-by-step 
either upwardly or downwardly, for initial viewing in one direction or for 
reviewing images already seen a moment earlier. 
It has been indicated above that it is advisable not to have any light 
illuminating the images at the time they are moved from one position to 
the next position, in order to eliminate any eye strain which may be 
caused by looking at illuminated images when they are moved. This result 
may be accomplished in two ways. First, the source of illumination may be 
actually turned off, as by the above mentioned electric switch mechanism 
163, 165, 167 controlled by the notches 161 on the periphery of the disk, 
in those embodiments of the invention in which the images are carried by a 
disk, or by similar notches (not shown) in the edges of the wide film 
strip, in those embodiments using such a film strip. Second, while leaving 
the light on instead of turning it off, a shutter may be closed across the 
field of view of each eye piece, to block out the view as the illuminated 
disk turns. The opening and closing of the shutter may be accomplished by 
an electromagnet or solenoid operated by the same switch mechanism 163, 
165, 167 which is wired up to operate the shutter instead of operating the 
illumination. 
In FIG. 4 there is shown a series of small holes 175 extending through the 
disk near the outer edge thereof, in the spaces between successive radial 
rows of stereoscopic images, and outwardly of the outer circle of key 
indications 173. These small holes 175 are optional, and when used, they 
may be provided for controlling a light beam which, in turn, through a 
suitable conventional photo-sensitive cell, stops the turning of the disk 
from one position to the next successive position. Or again, the 
interruption of a light beam when the disk turns and the reestablishment 
of the light beam through one of the holes 175 when the disk reaches the 
next position may be used to control the starting and stopping of audio 
apparatus, such as a magnetic tape, which gives an audible message related 
to the display of the stereoscopic pictures. 
It has been mentioned that compressed air is the preferred form of motive 
power for turning the disks in the embodiment illustrated in FIGS. 12-18. 
However, it is within the scope of the invention to use solenoids or 
electro magnets in place of the air cylinders illustrated in FIGS. 17 and 
18. It is also contemplated to use electric motors. If the separate disks 
in this embodiment (FIGS. 12-18) are to be mounted for upward and 
downwward movement as in the present illustrations, to accommodate people 
of widely different height, a separate electric motor in each of the 
upwardly and downwardly movable cabinets 261 is advisable. If, however, 
the feature of accommodating people of different height is eliminated and 
the various disks are mounted in stationary cabinets, then a single motor 
of larger capacity could be used, driving a shaft extending through the 
whole length of the mechanism from one end to the other, with power 
take-off at intervals along the shaft, by gears or belts, for driving the 
individual disks through their step-by-step turning movements. 
In connection with the projectors illustrated in FIGS. 21 and 22, it has 
been mentioned above that the projection lens carriers 413 and 513 are 
movable laterally to align the projection lenses with one or the other 
groups of stereoscopic pairs of images on the disk or the wide film strip, 
as the case may be. However, it is within the scope of the invention to 
omit the feature of lateral movement of the projection lenses, and to 
provide, instead, for lateral mechanical movement of the entire disk or 
the entire film strip, in order to bring stereoscopic pairs of images from 
the selected group of images into line with the projection lenses. 
The use of the automatic audio stereoscopic color sequences as produced by 
the mechanism disclosed in FIG. 21 will achieve more conviction in the 
teaching of all of the solid sciences, such as microbiology, botany, 
geology, surgery, architecture, etc., it is believed, than conventional 
teaching techniques heretofore used. 
The precision aligned stereoscopic sequences sandwiched within rugged, 
rigid disks are engineered to function for two purposes: (1) for 
projection, preferably from hidden mechanisms; and/or (2) for additional 
reviewing in automatic, solo or duo viewing stations, similar to that 
shown in FIG. 5. In one advantageous method of use, the truthful color 
stereo sequence disks are projected onto a screen to be seen by seated 
students. Immediately after the authoritative type lectures, duplicate 
stereo pictorial disks with related audio cassettes are inserted into 
either solo or side-by-side duo automatic audio viewing stations located 
in the school's library and/or in dormitory halls, available for day and 
night reviewing. These reviewing stations may be similar to FIG. 5, plus 
binaural speakers like those shown at 303, 305 in FIG. 12. 
The dual pairs of stereograms on a single roll of film have valuable 
potentials for use as stereoscopic motion pictures. The insertion of rolls 
of wide film into a custom built projector eliminates serious 
synchronation problems that happen when rolls of left eye images are 
projected from one projector and the right eye images have to be projected 
from a second projector. The 51/2 inch wide rolls bear larger images then 
those four sprocket hole high images that are currently being used in 
theatrical installations. Further patent applications will present more 
details.