CA1252324A - Multiple projection optics slide projection apparatus using a circular slide tray, having fixed-position slide gates - Google Patents

Abstract

MULTIPLE PROJECTION OPTICS SLIDE PROJECTION
APPARATUS USING A CIRCULAR SLIDE TRAY, HAVING FIXED-POSITION SLIDE GATES

Abstract A slide projector having two projection optics systems (12,14) for display of slides on a screen. Each projection optics system includes a fixed position slide gate (24, 36) into and from which slides move relative to a circular slide tray (16), which rotates about a fixed verti-cal axis to access each compartment therein relative to both slide gates.

Description

Descrl ~ on M~LTIPLE PROJECTION OPTICS SLIDE PROJECTION
APPARATUS USING A CIRCULAR SLIDE TRAY,~
HAYING FIXED-POSITIO~ SLIDE GATES

Technical Field This invention relates generally to thP slide projector art~ and more specifically concerns a multiple projection optics slide projection system which includes a circular slide tray and two fixed-position slide gates in which slides are projected.

Ba~round Art In the consumer slide projector market, the most successful design in recent years incorporates a circular slide receptacle or tray, for storage of the 91 ides to be projected~ In operation, the slide tray, which is mounted on top of the slide projector, is rotated abou~ a fixed verti-cal axis so that the compartment containing the slide to be projected is in regi5try with the slide gate therebeneath.
The slide moves through a slot in the bottom of the slide tray by gravity into the slide gate and is then projected.
Following projection, the slide is moved by a mechanical lifter from the slide gate back into its compartment in the slide tray. The same process occurs for each slide to be projected.
Exemplary of this design currently on the market is a Kodak slide projector and its mating slide tray, sold, respectively, under the trademark Carousel. An example of a similar projector in the patent literature i~ U~ S. Patent ~5~

No. 3,276,314 to Robinson. Such mechanically operated and controlled slide projectors have been extremely successful in the consumer slide projector marketO
However, such conventional slide projectors have only one projection optics system, including a single pro-jection lens. Thus, the previously projected slide must be moved from the slide gate back into its original compartment in the slide tray before the next slide can be moved into the gate and projected. Thi~ results in a delay between the projection of successive slides7 Lap-disYolve projector arrangements have been developed to eliminate this delay and provide a smooth tran-sition between successive slidesO In one solution, which is currently used extensively, several single optics slide projectors are operated together, controlled by an interface device. It is not uncommon for three or even more projectors to be used together for a sophisticated slide presentation.
Another solution i~ a single projector having multiple projection optics systems. However, significant difficulties have been encountered with 5uch an arrangement, particularly with respect to the slide movement between the slide tray and the two optics systems. Initial attempts included two magazine-type slide trays, one for each optic~
sy-~tem. Such an arrangement basically is two p~ojectors contained in a single housing. The next development used a sin~le magazine or drum slide tray in which slides were moved out of the slides of the slide tray. The slide tray wa~ moved forwards and backwards in a particular sequence in order to maintain proper storage of the slides. Such a StLU-ctur~ is shown in U. S. Patent No. 3,462,215 to Floden.~lthough the optic~ systems for both of the above solutions are relatively simple, neither solution was usable with a circular slide trayO
Initial development of a multiple-optics slide projector which was capable of using a circular slide tray is ~hown in U. S. Patent No. 3,501,233 to Winkler et al.

~ ~s~

However, the Winkler structure is quite complicated, in-clude~ a slide tray support structure in which the ~ray is alternately rocked about points on opposing sides of the tray, and more importantly, reyuires a careful initial pos-itioning of the slides into two separate group~ in the tray.
The next advance in the art is exemplified by U.
S. Patent No. 3,6fl9,140 tO Harvey, which teaches a circular slide tray and two projection optics systems, in which 81 ides can be loaded in the tray in a normal sequence How-ever, the tray in operation is shifted laterally to acsessthe two slide gates, as well as rotated. Such a structure is complex mechanically and expensive to implement. The next development in the art is exemplified by Patent No.
4,165,161 to Kramer, which solved ~he problem of Harvey by uslng swinging slide gates, which moved in operation between a common load position and separate project positions. The Kramer structure, how0ver, is also fairly complex and fairly ~ophisticated to both operate and maintain~
Thus, the lap-dissolve ~lide projectors known to the art at the t~me of applicant's invention were quite complex mechanically, particularly with respect to the tray drive system and/ox the projection optics sy~em, an~ in ~ome cases required special loading of the slides in the slide tray.
Disclosure of the Invention Accordingly, the present invention is a slide projection apparatus which is adapted to carry a circular slide tray which has a lower pan portion with at least one slot therein through which slides can move and an upper receptacle portion comprising a ~eries of compartmant~ in which slides are arranged in a predetermined sequence, thP
receptacle portlon being rotatable relative to said pan portion about a single vertical axis. The projection appara-tu~ includes first and second projec~ion optic~ systemsdefining first and second image projection paths, each pro-~ :il ~5~3~f~

jection optics system including a fixed-position slide gate located beneath the circular slide tray, wherein slides move into and from said slide gat~s ~elative to the circular slide tray, the image projection systems being arranged 5 relative to each other and to the slide tray such that each compartment in the slide tray can be brought into regis~ry with each slide gate and such that slides poRitioDed in the slide tray in the predetermined sequence can be displayed without reversal, in said predetermined sequence. The ~lide 10 projection apparatus includes means for rotating the circu-lar slide tray about the fixed vertical axis to access each . compartment of the circular slide tray relative to each 51 ide tray.

15 Brief Description of the Drawings Figure 1 is a plan view of one embodiment of the slide projection ~pparatus of the present invention~ showing two independent projection optic~ sy~tems, with fixed posi-tion slide gates, the slide tray for the apparatus being 20 shown superimposed relative to the projection optic~ sys-tems.
~ igure 2 is a single projection lens embodimen~ of the slide projection apparatus shown in Figure 1.
Figure 3 is a variation of the embodiment of Fig-25 ure 2, with only one light source.
Figure 4a is a plan view showing a portion of one embodi~ent of the tray drive structure of the present inv2n-tion which can be used with any oE the embodiments of Fig-ures 1-3.
Figure ~b is an elevation view of the structure of Figure 4a.
Figure 5a is a bottom plan view showing a portion of another embodiment of the tray drive ~tructure of the present invention which can be used with any of the embodi-35 ments of Figures 1-3.

s Figure 5b i~ an elevational view of the embodiment of Figure 5a, Figure 6 i5 an elevational view showing a str~c ture for driving the receptacle portion of the ~lide tray which can be used with the embodiments of Figures 4 and 5.

Best Mode For Carryin~ Out The Invention Figure 1 shows one embodiment of the apparatus of the pre~ent invention, in which each of two projection op-tic8 systems includes a separate projection lens. The slidetray is shown superimposed in dashed outline to ~how the relationship between the two projection optic~ systems and th~ tray.
Projection optics system~ 12 and 14 are contained in a conventional projector hou~ing 10. A single circular slide tray 16 is used to store the ~lide~ for the apparatus.
~he slides may be conventionally loaded in the slide tray in the sequence in which they are to be displayed. In opera-tion, slide~ move from slide tray 16 by gravity~ lo~ered by a conventional lifter apparatus (not shown), into one or the other oE the projeetion optic~ eystem~, and are moved rom the projection optics system~ back into the slide tray 16 by means o~ the lifter. The particular mechanism or a~tually moving a slide between the slide tray and the image projection s~tems form no part of the present invention, and hence is not shown herein in detailO Referen~e i~ made to the patents mentioned above, particularly the '161 pat-ent, for example~ of approximate ~lide moving structure.
Projection optics ~yst*m 12 define~ a straight projection path along the left ~ide of the projector. It include~ a conventional light source 18~ a heat filter 20, a conden~er len~ 22, a fixed po~ition ~lide gate 24 into and from which slides are moved relative to the tray 16~ and a projection lens 26~ An additional light filter element ~not shown) can be positioned in projection op~ic~ ~ystem 12 to equalize the light on the ~creen between the two optic~

systems, if necessary. The indlvidual elements par se of the projection optics ~ystem 12 and their relative spacing are known in th~ art. Slide gate 24 in the pr~ent invention is positioned within the projector apparatus such that the compartments of the 51 ide tray 16 may be sequentially moved into registry therewith by rotation of the tray alone~ i~e.
without lateral movement or rocking of the tray~
Projection optiGs sy~tem 14 defines an angled projection path~ The ini~ial portion of the projec~ion path Of optics system 14 is at an angle to the projection path of projection optics system 12. ~he remaining portion of the projection path of optic~ sy~tem 14 is parallel to the pro-jection path of optics system 14, so ~hat the lon~itudinal axe~ of the respectiv~ projection lenses thereo~ are paral-lS lel. P~ojection optics system 14 includes a light source 30,a heat filter 30, a condenser lens 34, a fixed po~ition slide gate 36, a reflecting mirror 38 and a projection lens 40. Again, the ~lem*nts per S8 of projectlon optic~ sy~tem 14~ including mirror 28~ and the relative spacing thereof, 29 ar~ known-Projection optics sy~tem 14 is arrangPd 8C thatthe slide tray compartments can be moved sequentially into registry with the slide gate 36, and slide gate 24, by rota-tion of the tray alone, without any lateral movement there-Of D Further~ projection optic~ sy~tem 14 is arranged rela-tive to projection optics system 12 ~uch that the re~pective pro~ection lenses 26 and 40 are ~ub~tantially adjacent each o~her~ with projection lens 40 being positioned slightly forwardly of projection lens 26. The arrangement of Figure 1, as with the arrangement of Figures 2 and 3, permits slides to be load~d in a conventional sequence in the ~lide tray and di~played in that sequence, without any reversalO
Thus, special loading of the slides in the slide ~ray is not necessary, ~ ~ ~5;~

The fixad position slide gates 24 and 3S are con-ventional in construction, configured and arranged 50 aB to hold a ~lide firmly in position by clamping, typically at one side toward the other side and against the face of the slide, following movement of the slide from the tray into the gate. After the slide has been projected, the slide is lifted back up into iks original compart~ent in the slide tray, typically while it i5 still clamped. The clamps on the gate a~e then released to allow the movement of the next slide into the gate.
In the embodiment shown, the arrangement of the respec~ive projection optics systems 12 and 14 is such that the hou~ing within which they are positioned i~ approximate-ly the size of a conventional slide projector. The two fixed ga~e~ ~4 and 36 in the embodiment shown are at an angle of approximately 105 degrees relative to each o~h~r. ThiR ar rangement h~s proven to be advantageous in th~ spacing of the two projection optics sy tems, but also re~ults in a relatively close side-by-side positioning of the respective projection len~e~ thereof, with a relatively ~inimum dif~er-ence ~approximately 1/2 inch) in the relative longit~dinal po~ition thereof~
In an alternative arrangement, projection optics ~ystem 14 is arranged at an angle of approximately 65 de-grees, similar to that shown in Figure 2. In thi~ arrange-ment~ again referring to Figure 1, the mirror 38 i~ posi-tioned on the other side o the projection path oE
projection optics sy tem 12, 80 that the projection path of optic~ system 14 in effect cros~es the projection path of optics system 12. In all such embodiment~, however, the di~tance between the Plide and the projection lens in each optics system i~ the ~ame if the ~ame projection len~e6 are used in each optic system~ The two projection lenses 26 and 40 are supported such that ~hey can be mov~d toward and away from each other to accomplish image separation, such as di~closed in U. S, Patent No. 4,41-6,520 to Milo Kramer.

In Opera~iOD of the apparatus of Figure 1, slide tray lS i8 rotated about a fixed vertical axis, without rocking or other lateral movement, to service both projec-tion optics systems. Tray 16 i~ driven at its rim by tray drive element 420 The conventional 80 compartment slide tray 16 includes a plurality of downwardly projecting pin-like alements at its periphery, which in one çmbodiment are operated on by a gear portion of drive element 42 to pro-vide the desired po~itive control over the movement of the tray. Such a sy~tem can only ~e used, however, with the 80 compartment tray. In both the 80 compartment and the 140 compartment trayg the lower periphery o the slide tray ha~
a notch in it. Another tray drive embodiment includeQ a drive ring which surrounds the peripheral edge of the tray and has a projection which engages the notch in the tray.
The drive ring in turn is driYen by element 42, Such an embodiment can be used with either the 80 or 140 compartment tray. ~he ~equence of movement of the ~ray, as well as additional disclosure concerning the tray driv~ ~ystem; will

2~ be di~cussed in more detail hereinafter.
Figure 2 shows an alternative embodiment u~ing only one projection lens. A first projection optics system 50 includes a light ~ource 52, a heat f i 1 ~er 54, a condenser lens 56 and a fixed slide gate 58. ~mage splitter 60 and projection lens 62 are shared with the other projection optic~ system 51. Projection op~ics sys~em 51 comprises a light BOurCe 64, a heat filter 66, a condenser lens 68 and a slide gate 70, in addition to image splitter ~0 and projec-tion lPns 62. Projection optics ~ystem 50 define~ a straight image projection path along the left side of the projector; similar to that shown for the embodiment of Eig-ure lo The image of optics system 50 is projected through image 5pl itter 60 and through projection len~ 62 onto the screen~

Image projection system 51 i~ po~itioned in the embodiment shown such that its ~ixed slide gate 70 is at an angle of approximately 65 degrees relative to ~lide gate 5B
in projection optic~ system 50. Thus, the im~ge projection path of projection optics system 51 is angled, with the image being reflected from image splitter 60 and then through the single projection lens 6~ onto the creen. The arrangement of Figure 2 is advantageous because it res~lts in a reduced projector ~ize, and is less expen~ive and eas-ier to operate.
Figure 3 ~ho~s a variation of the embodiment ofFigure 21 with only one light source. Two projection optics system~ 72 and 74 are arranged ~imilarly to those shown in Figure 2/ sharing an image splitter 76~ and a single projec-lS tion lens 78. Both projection optics system share in addi-tion a single light source 80, the light from which i pro-vided to the respective projection optics system~ by means of a 1 igh~ shutter 82 and replecting mirrors 84 and 8S.
Mirrors 84 and 86 could be "cold" mirrors, which pass most of the infrared light while re~lecting the rest of the light. I~ may be possible to eliminate ~he heat filter~ with such an arrangeMentO
Light shutter 82 in the embodiment shown co~prises two thin vertical plates supported in a track/ the plate~
2S having a xeflecting surace nearest light source 80. When ~hutter 82 i~ ope~, light from ~ource 80 i reflected off mirror 84 into the path of projection optics system 74~
When light ~hutter 82 i~ closedl light from source 80 is reflected off shutter 82, through a heat filter 90, and then i~ reflected off m$rror 86 into projection optics sys~em 720 The arrangement of Figure 3 ha~ the advantage of elimi-nating blackout flaps, and po3~ibly di~mer control circuitry a~ well, which are necessary in more conventional lap-dis-solve slide projectors.

, }~x~ .... . ....

~ 5~

Figures 4A, 4B and 5A, 5B show two embodiments for moving thP slide tray between the two fixed gates in any of the embodimen~s of Eigures 1-3c A conventional ciroular ~ray to be used with the present inven~ion includes a bottom metal pan portion 100 and an upper slide recep~acle portion 102f typically made of plastic. The slide rec~ptacle portion iB divided into compartments, typically 80 or 140, which house the 31ide3. The tray i8 arranged such that the recep-tacle is movable relative to the pan, ~hen the ~lide tray ig po~itioned by the operator on a conventional slide pro-jector, the pan is engaged so that in operation i~ remain~
fixed in po3ition while the receptacle rotates relative thersto to acce~s the Rlldes.
In the conventional cs~mercial slide ~ray; the pan ha~ one slot therein through which slide~ move between the ~lide receptacle and the slide gate in which ~lides are projeoted. In a irst embodiment of the tray drive ~tructure of the pre~ent invention; shown in Figuree 4A, 4B, the conventional pan i9 modified by cutting another slo~ 101 in the pan 100, ~lmilar in size and configuration to the orig-inal ~lot, The additional ~lot i~ po~itioned in the pan 100 ~uch that when the ~lide tray i~ positioned on the ~lide pro~ector of the pre~ent invention, the two 810ts ar2 po~i~
tioned directly over the fixed ~lide gates. With this em-bodiment, it is unnecessary to move the metal pan 100 during operation of the slide projectorO The desir~d compartment in the ~lide receptacle 102 is addres~ed by movement of th receptacle 102 relative to the pan 100, a~ is the case for a convantional slide projector O
As~ociated with each ~lide gate in the above em-bodiment is a slide retainer or ~hoe and a ~lide lifter.
Referring ~pecifically to Figure~ 4A and 4B, which show~ the ~hoe and the lifter for one slide ga~e, the ~lide ~hoe in-cludes an elongated arm 104 with a small rounded foot 106 at the end thereof. ~n the embodimen~ shown~ arm 104 and the foot 106 are aligned along the qame radiu~ as its asqociated slide gate. The slide shoe i~ mounted such that it moves bstween ~wo po~itions in a subs~antially radial direc~ion J
~hrough a piston-like action accomplished by means of a ~olenoid or similar mechanism ~not shown). It should be understood, however, that the ~lide ho~ could be mounted and move in other direction~, such as at a right angle or tangentially to the slot, as opposed to radially.
Referring again to Figure~ 4~ and 4B, foot 106 and th arm 104, in their retraGted position, are completely free or removed from the slo$ 101 in the pan 100, which slot i~ directly over the slide gate and the slide therein 108, if any. In the retracted position, thP slide shoe has moved radially towards the center of the slide tray. In the extsnded po~ition oP the slide ~hoe, oot 106 i5 approxi-mately at ~he midpoint of 510t 101, with a portion of foot 106 extending upward into slot 101 so that there exists a continuous surface over a portion of ~he total length of the slot~ In this position of the slide shoe, the receptacle 102 i free to rotate without the slide~ dropping through either of the slots in the pan 100.
To load slides into the slide gates, recsptacle102 ~ rotated until tha compartment containing the desired ~lide to be projected i~ in ~egi~try with the fir~ ~lide gateO The lifter 112 i in the raised position, having re-25 mained ~here following the lifting o~ the previous slideback into its original compartment or having moved ~p with-out a slide prior to the loading of the first slide into the gateO The slide shoe in the embodiment shown is in the ex-tende~ position when the receptacle moves and there is a ~lide in the slide gataO ~hen there iB no slide in the qlide gatep the lifter i~ raised, and th~ slide shoe remains in its retrac~ed position. The slide shoe and ~he lift0r are arranged so that they can move as explained above without interfering with each other~

,< ~,r. ' ! ' ' After the ~lide shoe is moved, if necessary, from it~ extended position to its retracted position, the slide to be projected re~ts on the lifter, and the slide in ef-fect drops by gravity, but guided by the lifter, into th2 slide gate, clamped as explained above. There is al~o a slide drop sensor in the ~orm of a light sen~or or the like Inot shown) which provide~ an indication of the dropping of a slide. Tn soms cases9 it will be undesirable to drop a 51 id~, and when the sensor iR ~ctuated, the 81 ide shoe can be brought back to its extended position under the slide, thereby preventing the ~lide from reaching the slide gate.
Af ter the 51 ide has raached the slide gate and clamped, it is projected. The ~lide shoe is then moved back to it~ extended po~ition. The lide recepkacle 102 is the~
moved until the compartment containing ~he desired ~lide to be pro~ected i~ in rPgistry with the second ~lide gate. The slide ~hoe for that gate is ln it5 extended position, it is moved to its retracted po~ition~ as explained above, and that slide then moves by gravity, with the lifter ~uppoLting 2~ it; into the slide gate, where it is ready to be projected ollowing the projection of the ~lide already in the first ~lide gate. ~he slide shoe for the second ~lide gate is ~hen moved back in it R extended po~ition.
~he receptacle 102 is then rota~ed back ~o that the compartment originally containing tha fir~t desired ~lide i3 again ln reqistry with the first ~lide gate. When the projection of that slide in the irst slide gate is completed~ the slide ~hoe i8 retracted and ~he slide lifter 112 i~ opexated to lift the 81ide back up into the compart~
ment. ~he lift~r ~tays up, with the slide ~hoe retracted 9 and the receptacle is then rotated to acces~ the compart-me~t containi~g the next slide to be projected with the first ~lide gate. Thi~ process continue3 for each slide to be projected in sequence between the two fi~ed gates. After tne presentation is complete, the slide tray is removed from the projec~or in conven~ional fashion.

Figures 5A and 5B shsw a ~econd embodimen~ for driving the lide tray in the pre3ent invention. In this embodiment~ th~ slide tray pan 120 ha~ only the one conven-tional ~lot 1~1, and therefore is ldentical to a conven-tional panO Conventional commercial circular ~lide tray~ canthus be used without any modification in this embodimen~v ~xt~nding slightly downwardly from th~ bottom ~urface of the tray pan 120 i~ a dimple 122, in the center of which i~ an opening 124~ The projection apparatu6 of the pre~ent inven-tion include~ a small vertical pin 126 ~ee Figure 5B),mounted on a section of gear 128~ which i typically po~i-.tionad in a clo3ed track or ~lst (~ot shown) in the projec-torO The gear and pin structure i~ so positioned that when the sllde tray i8 po~itioned on the projector, in it~ ref-erence position, pin 126 extends upwardly through opening124, engaging the metal pan of the ~lide tray.
The gear ~ection 128 i~ driYen through a horizon-tal arc by a gear 132, which in turn is driven by a motor 130. Thus, in thi~ embodiment, the tray pan 120 is po~-20 i'~ively driven~ independently of the slide receptacle 129.In the ~equence o movements of th~ tray to load or unload ~lide8 from the r~spective fi~ed ~lid~ gates, the tray pan 120 is first moved 40 that the ~lot in the tray pan i8 in registry with the particular ~lide gate which i~ ~o be loaded/unloadedO
A ~ingle ~lide sho~ in the embodiment shown~
moves with the tray pan in an ~xtended po~ition, to block any po33ible movement of ~lide~ through the ~lot., Alterna-tively, the projector could include a ~erie~ of flxed shoes along the path of the slot between the two slide gates whlch operate in ~equ~nce to provide continuou~ support benea~h the 310t a~ it move~, or the tray could be moved as a com-plate unit with an empty compartment above the ~lot. Typi--cally~ but not neces~arily, th~ ~lide receptacle moves with 35 the tray pan when the tray pan i~ moved to po~ition the slot th~r~in in registry with a ~lide gate. When the ~lot i po~Qitioned, the re~eptacle i~ then moved independently to acce~s the desired compartment. The shoe i~ then retracted and the slide may be moved.
More ~pecifically with respect to the operational sequence, a~suming that the re~Qpective slide gates are 5 initially both empty, the slide ~ray is first positioned by the operator in it~ reference po3itlon on the projector. The tray pan and the r~ceptacle are then rotated as a unit a~
explained above until the ~lot 121 in the pan 120 i3 in registry with the first slide gate. The slide receptacle 129 is th~n moved alone until the compartment containing the fir~t slide to be projected i~ in registry with the ~lot 121 and the first sl1de gate. The li~ter ~not shown) i5 Up a~
thi~ point. ~he slide shoe (not shown) is then retracted, opening the ~lot, and the first slide move~ down into the 15 slide gate by gravity, reQting on the lifter. The ~lide ~hoe ig then extended. ~he tray pan a~d the tray receptacle are then moved as explained above to load the second slide into th~ ~econd slide yate.
The tray pan and the xeceptacle are then rotat2d 20 back together to the point where the 510t 10l i~ above the firat slide gate. The slide receptacle i~ then rotated by itself to the point where the compartment originally con-taining slide one iQ in registry with the slot 101 and the ~lid2 gate, The ~hoe is then retracted and the lifter i5 25 actuated, moving the slide back up into the compartment.
Tha lifter remains in the raised po~ition. The ~lide recep-tacle i~ then rotated so that the compartment containing the third slide to be projected i5 in registry with the ~lot and the 81 ide gate, and the slide lowered into the ga~e for 3û pro~ection. Thi~ proceQ~ continue~ until the 31ide prl3senta-tioT~ i~ completed~
The ~lide receptacle will typically have either 80 or 1~0 compartment~, The 80 compartment receptacle typically includes a plurallty of lug~ or pi~8 which depend downwardly from the lower peripheral edge of the ~ray, one lug for each compar~ment. In one embodiment, ~he receptacle i3 then driven a~ shown in ~igure 5Br with gear 112 ma~ing with the lug~ on the tray and mo~or 114 driving the gear. The 80 and the 140 position receptacles both have a single notch in 5 their lower peripheral surface. In another embodiment, drive ring surrounds the lower peripheral edge of the tray, with a projection which extends into the notch in the tray. Figure 6 ~hows a portion of a tray receptacle 140, th~ notch in the lower edge thereof 142~ and the drive ring with its projec-10 tion 1~4. The drive ring is rotated by a gear 146, which i8driven ~y a motor 148. Such a driYe ~tructure for the 8Q
compartment tray i5 an alternative to the s~ructure des-cribed above~
Thus, an apparatus has been de~cribed which pro-15 vide3 a multiple i~age slide prcjection capability with fixed slide gate~ using a conventional circular slide ~ray which is rotated about a fixed central vertical axi~
though a preferred embodiment of the invention has been disclo~ed herein for illustration, it should be understood that various changes, modifications and ~ubsti~utions may be incorporated in such embodiment without depar~ing from the spirit o~ the invention a~ defin~d by the claims which fol-low~

Claims (10)

1. Claim 1. A slide projection apparatus which is adapted for operation with a circular slide tray which rotates about a central vertical axis and which has a lower pan portion with only one slot therein through which slides can move and an upper receptacle portion comprising a series of compartments in which slides are arranged in a predetermined sequence, the apparatus comprising:
   first and second projection optics systems defining first and second image projection paths, each projection optics system including a fixed position slide gate located beneath the slide tray, wherein slides move into and from said slide gates relative to the circular slide tray;
   means for rotating the lower pan portion of the circular slide tray and the upper receptacle por-tion and for rotating one portion independently of the other portion, so that the one slot in the lower pan portion and the compartments in the upper receptacle portion can be brought into alignment with the slide gates; and means for controlling the rotation of the slide tray and for controlling the movement of the slides into and from the compartments of the slide tray in such a manner that the compartments of the slide tray can be accessed with respect to either slide gate, so that a sequence of slides present in consecutive compartments of the slide tray may be displayed in said sequence using the first and second projection optics systems in any sequence.
2. 2. An apparatus of Claim 1, including means permitting slides to move by gravity from said circular slide tray into the respective slide gates, and means for moving a slide in the respective slide gates back up into the circular slide tray.
3. 3. An apparatus of Claim 2, including means for moving the slide pan portion of the slide tray with, and independently of, the slide receptacle por-tion of the slide tray.
4. 4. An apparatus of Claim 3, wherein said rotating means includes means for rotating the slide receptacle at the rim thereof.
5. 5. An apparatus of Claim 1, including means in one of said projection optics systems for reversing the image thereof.
6. 6. An apparatus of Claim 1, wherein said respective fixed gates are separated by an angle of approximately 115 degrees, and wherein each projection optics system includes its own projection lens.
7. 7. An apparatus of Claim 1, wherein said respective fixed gates are separated by an angle of approximately 65 degrees, and said first and second projection optics systems share an image splitter and a projection lens.
8. 8. An apparatus of Claim 7, wherein said first and second projection optics systems share one light source, the projection apparatus including means for selectively directing light from said light source into said first and second projection optics systems.
9. 9. An apparatus of Claim 1, wherein the circular slide tray rotates about a fixed vertical axis.
10. 10. An apparatus of Claim 1, wherein the first and second projection optics system are arranged such that in one image projection path, the slide im-ages are directly projected through an image splitter, and in the other image projection path, the slide im-ages are reflected off the image splitter, undergoing an image reversal in the process, so that slides may be positioned in the compartments of the slide tray in a single orientation, without means in either of said first and second projection optics systems for revers-ing the image of the projected slides, other than said image splitter.