Classifications

• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03B—APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
  • G03B23/00—Devices for changing pictures in viewing apparatus or projectors

Definitions

• the present invention makes it possible to eliminate the torment which is imposed on the eyes of observers.
• Patent documents DE 2657697, FR 2374663 and US 4130353 describe a mechanism simultaneously moving the slide which has just been projected and that which is going to be, which considerably reduces the moments of darkness but insufficiently not to be perceived by the eyes.
• Patent documents DE 2925714 and EP 21Q0S describe a process consisting in interposing, during the changes of slides, between their projection location and the objective, a network of multiple lenses provided, on its illuminated face, with a cover pierced with holes virtually located through said lenses in said location, which makes it possible to illuminate the screen without the displacements of the slides and their frames appearing distinctly therein, but these illuminations are variable in intensity and of moving density.
• Patent documents DE 2723786 and GB 1582972 describe a combination of three mirrors deflecting part of the light emitted by the lamp of the projection device and one of which, pivoting about an axis which is parallel to it, directs on the lens, during slide changes, the said part of light having passed through an optically interchangeable color filter located at the same distance from said objective as the projection location of the slides, which makes it possible to illuminate the screen by hiding the movements of the slides and their frames but the clear image of said filter moves to the outside of the screen during the pivoting of the pivoting mirror and trembles during its twists and turns; moreover, this image, which is clearly smaller than those of the slides, must be clearly brighter in order to obtain a sufficient physiological effect and, by remanence of the locally more excited retinas, is briefly superimposed on each new slide image.
• the previously projected slide can be exchanged with that to be projected later in a device while the other projects another previously exchanged slide with the previously projected one and the passage from one image to the next on the screen can be done either suddenly, knows by varying the light fluxes progressively in one device and gradually in the other; this process is expensive and complicated, the images obtained by overlays are unreal and often not harmonious because the subjects lend themselves to it only rarely, and it has the disadvantage of the alternative arrangement in two magazines of the slides to be projected successively, however, the Patent documents DE 2930959 and EP 23945 describe a double device comprising a double mechanism making it possible to project, by one of its two lanterns alternately, the slides stored successively in a single store.
• this apparatus includes produces, during each change of slides, without perceptible discontinuity and without asymmetrical mobility that the eyes would instinctively follow, a transient illumination of the pleasantly diffuse and colored projection screen, without dust images, delimited preferably in the same format as that of the images of slides or at least of a surface common to the horizontal and vertical orientations wedges of rectangular images, of constant light intensity and density and ophthalmically approximately equivalent to those of slide images so that the size of the pupils of the observers is kept constant without remanence of the excitation of their retinas and, the deformation of their lenses remaining as constant, each new image immediately appears clear to them.
• the slide changes are thus transformed, efficiently and aesthetically, into beneficial moments of relaxation, the observation of slide images becoming otherwise demanding.
• the screen remains pleasantly lit even if there are missing slides in their store and during each change of stores.
• Fig. 1 schematically shows a first embodiment of the invention operating by detecting variations in the brightness of the screen.
• Fig. 2 schematically shows a second exemplary embodiment operating by detecting the presence and absence of a slide in the projection position.
• Fig. 3 shows the holes, of a particular shape, superimposed on the shutter tape of the projection beam of the slides in the exemplary embodiment according to FIG. 10.
• Fig. 4 shows the holes, of a particular shape corresponding to that of FIG. 3, superimposed on the shutter tape for the beams producing the transient illuminations of the screen in the exemplary embodiment according to FIG. 10.
• Fig. 5 shows in isolation said form of FIG. 4.
• Figs. 6 and 7 each show a form of drilling of the mask for delimiting the transient illuminations of the screen in the exemplary embodiment according to FIG. 10.
• Fig. 8 shows the shape obtained by superimposing the covers according to FIGS. S and 7.
• Fig. 9 shows schematically and very reduced the illumination of the screen corresponding to the positions of the shutter ribbons as shown in FIG. 10.
• Fig. 10 schematically shows a third exemplary embodiment of the invention with progressive appearances and disappearances of the transient illuminations of the screen and the images of slides by variations of their surfaces. Ways to realize the invention
• the miniature lantern shown in Figs. 1 and 2 comprises a lamp 1, a condenser 2 and a lens 3 of short focal distances, as well as a concave reflector 4 possibly necessary; this embodiment of said complementary headlamp is not limiting and could be replaced, for example, by a paraboloidal mirror headlight.
• the color, preferably green resting for the eyes, of the transitory illuminations of the screen is obtained by means of the filter 5 which can be interchangeable.
• the delimitation of the transient illuminations of the screen preferably in the same format as that of the images of the slides, is obtained, so as to never project dust images on the screen, by the image of the periphery of the hole 6 of the cover 7.
• the distance from the cover 7 to the objective 3 can therefore be fixed, this distance having been predetermined for an average size of the screen.
• the hole 6 of the cover 7 may be of an intermediate shape, round or square, although the cover 7 may be interchangeable or even integral with the objective 3 which it suffices to pivot from a quarter turn, simply manually, to orient the hole 6, then rectangular, of the cover 7 horizontally or vertically; this pivoting can also, by means of an electro-mechanical device, be controlled from a remote control and / or be programmed and then take place during transient lighting of the screen.
• the interchangeability of flow and / or delimitation transient illuminations of the screen can also be obtained by means of disc [s] or ribbon [s], one comprising filters of different colors and / or another of the different holes, each disc or ribbon being maneuverable, its different positions are preferably identifiable by means of positioning lugs, manually and / or by means of an electro-mechanical device connected to a remote control and / or the control of which is programmable.
• Such a miniature lantern and its control can be, as shown schematically in FIG. 1, an accessory independent of a slide projection apparatus.
• the supply of the lamp 1 from the energy source 8 is controlled by detection of variations in the brightness of the screen by means of the ph ⁇ t ⁇ -voltaic cell 9, comprising an optical device projecting an image of the screen on its surface photo-sensitive, connected to the operational amplifier 10, mounted as a Schmitt trigger, controlling the engagement of the switch 11 as soon as the image of the projected slide disappears from the screen and releasing this contactor 11 as soon as the image d 'A new slide is superimposed on the transient lighting of the screen.
• the variation of at least one of the two resistors 13 and 14 makes it possible to adjust the rate of hysterisis of tilting of the output of the amplifier 10 and the potentiometer 12 makes it possible to adjust the operation of the circuit according to the excitations of the cell 9.
• the cell 9 can obviously be of another kind, for example a photo-transistor, by adapting to its characteristics the circuit controlling the sensor 11.
• the contactor 11 can be replaced by an electro-mechanical mechanism for shutting off the light beam emanating from the lamp 1 while constantly energized.
• the miniature lantern can also be incorporated into a slide projection apparatus and the supply of the lamp 1, from the energy source of this apparatus, can also be controlled via a contactor 11, as shown schematically FIG. 2, by means of the monostable switch 15 detecting the presence and absence of a slide in the projection position; the frame of such a slide actuating the lever 16 in the direction of the arrow 17, the switch 15 disconnects the contactor 11 which al ⁇ rs opens.
• the contactor 11 can be controlled, for example, by means of an opto-electronic device detecting the presence and absence of a slide in the projection position.
• the contactor 11 can be equipped with an inverter in order to supply alternately the lamp 1 and that for the projection of the slides.
• the miniature lantern can also be controlled mechanically by means, for example, of a second opaque flap coupled to that for closing the projection beam of the slides controlled by the frame of each slide coming into the projection position and by the mechanism removing this slide, the lamp 1 then being constantly on.
• the axis of the miniature lantern can also be preset for an average size of the screen.
• the miniature lantern can also, in the case according to FIG. 1, be incorporated into a slide projection apparatus and, in the case according to FIG. 2, being external to such a device then being dependent only by electrical connections or a mechanical coupling.
• One of the known devices for simultaneously varying the luminous fluxes of two beams can be used to control, twice in succession at each change of slides, said miniature lantern and that for the projection of the slides, the projected slide and the next being then exchanged between the first simultaneous, degressive and progressive variations, of the luminous fluxes of the beam of projectivity of the slides and of that producing the transient illumination of the screen, respectively, and the second variations, also simultaneous but respectively inverse, of the fluxes of these two beams.
• a monostable switch actuated by the frame of each slide in the projection position, allows, if there is no slide to be projected and until a new slide is in the projection position, to disconnect, at need via a contactor, the device control varying the light fluxes, that of the beam, producing the transient illuminations of the screen thus remaining at its maximum.
• this contactor can also be controlled, for example, by means of an ⁇ pto-electr ⁇ nic device detecting the presence and absence of a slide in the projection position.
• said miniature lantern can be incorporated into a slide projection device or be external to at least one such device then being dependent on it only by electrical connections having a mechanical coupling.
• the miniature lantern also comprises a lamp 1, a condenser 2, a concave reflector 4 possibly necessary, as well as a filter 5 and a possible cover 7 which may be interchangeable; in addition, a double prism 18 distributes the light beam from the condenser 2 on each of the two objectives 3a and 3b on either side of the opaque partition 19, which project the light which they each receive over half of the screen on the same side as they are.
• the slides are projected by means of another lantern comprising, partially seen, a usual source of light consisting of a lamp 20, a reflector 21, a condenser 22 and a heat-resistant filter 23, and a goal 24.
• the distance from the objectives 3a and 3b to the space between the cover 7 and the ribbon 27 can be predetermined and the axes of the two half-beams coming from these objectives can be preset for an average size of the screen.
• the opaque ribbons 25 and 27 shown schematically strongly thickened to clearly show the partial cuts, are driven by the drums 33 and 34 and move on the rollers 31a to 31c and 32a to 32d pivoting freely, respectively.
• the rollers 31a to 31c and 32a to 32d may advantageously include a flange, not shown, at each of their ends guiding the strips 25 and 27 respectively.
• the drive drums 33 and 34 are integral with one another and with the sector 35 which is partially toothed and meshed with the toothed wheel 36 of the motor 37.
• the mechanism for moving the strips 25 and 27 is shown in one third of the first phase of its operation.
• the change of slides is controlled by pressing the pusher 46 of the double switch 45 putting on the motor 37, which remains energized after release, by displacement of the stop 40 of the sector 35, of the lever 44 of the monostable switch 43 until that the stop 38 of the sector 35 actuates, by its lever 42, the double bistable reverser 41; the contactor 47, momentarily controlled by the capacitor 48, previously discharged by the resistor 49, controls the slide changing mechanism 50, shown only diagrammatically, which then removes the slide 29, the frame 30 of which thus releases the lever 51 from the monostable reverser 52 disconnecting the motor 37, hitherto disconnected by the contactor 47, until a new slide is in the projection position; the frame of this new slide actuating the lever 51 of the monostable reverser 52, the motor 37 is turned on again and, since the polarity at its terminals has been reversed, it drives sector 35 in the opposite direction until that its stop 40 actuates the lever 44 of the monostable switch 43 thus disconnecting the motor 37.
• the lever 44 of the switch 43 must be positioned in such a way that the double inverter 41 cannot be actuated before the switch 43 in order to 'prevent the motor 37 from continuing to rotate but in the opposite direction, the double inverter 41 can be actuated during the next command to change slides.
• Each change of slides is preceded by closing and then followed by the opening of windows 26a and 26b ru ban 25 closing and then gradually releasing the beam of projection of the slides and, simultaneously, preceded by the opening then followed by the closing of the windows 28a and 28b with the ribbon 27 releasing and then gradually closing the beams producing the transient stretching of the screen .
• the image of the projected slide therefore gradually disappears from two of its parallel edges while the miniature lantern, by its objectives 3a and 3b each reversing on the screen the opening of the windows 28a and 28b of the ribbon 27 on both sides. other of the partition 19, gradually illuminates the screen from said parallel edges as the image of the projected slide disappears and, conversely, the image of the next device gradually appears while the two halves of gradually disappear transient illumination, the screen thus being kept lit in a particularly aesthetic manner during each change of slides.
• the windows 26a and 26b of the tape 25 are also square and the windows 28a and 28b of the tape 27 are wider than they are high by the thickness of the partition 19; in this case, the cover 7 is not necessary.
• Fig. 9 shows, diagrammatically, the two halves of the transient illumination, corresponding to the horizontal lines, covering on the screen the "erased" parts of the image, corresponding to the vertical lines, of slide 29.
• the cover 7 is pierced with the hole 6, the length of which is increased by the thickness of the partition 19, seen in FIG. 6 or two holes 6, seen in FIG. 7, spaced from the sum of the thickness of the partition 19 and, proportionally, the difference between the length and the width of the slides according to whether they are oriented horizontally or vertically, respectively.
• the windows of the ribbon 25 can also have, in particular, these windows being superimposed, the shape shown in FIG. 3 and each of the windows of the ribbon 27 the shape shown in FIG. 5, FIG. 4 showing their superimposition in their positions corresponding to the positions of the windows of the ribbon 25 in FIG. 3, these overlays being seen from the side of the condensers 2 and 22, respectively; the diameters of the drive drums 33 and 34 are then doubled.
• the images of the slides disappear from their corners and appear from their center and, simultaneously, the transient illuminations appear from their corners and disappear from their center, the screen being kept lit even more aesthetically during each change of slides.
• the cover 7 must be drilled with a hole 6, wider than the thickness of the partition 19, seen in FIG. 4.
• the transient illuminations of the screen are limited to the part common to the two directions of images of rectangular slides mixed as regards their orientation, which is still very aesthetic and ophthalmically sufficient and which makes it possible to pass ideally from a horizontal image to a vertical image and vice versa; the cover 7 can obviously be simply drilled with the same two holes 6 as those resulting from this superposition or, if all the slides have the same horizontal or vertical orientation, be drilled as shown in FIGS. 6 to 7, respectively.
• the circuit connected by the monostable inverter 52 makes it possible to control, by pressing push-button 46 of the double switch 45, only the mechanism 50 for changing slides; it is thus possible to make the slide magazine go forward and backward] until a new slide can be brought into the projection position, the screen remaining lit by the miniature lantern.
• the presence and absence of a slide in the projection position can also be detected by an optoelectronic device controlling, for example, a contactor provided with an inverter replacing the inverter 52.
• an optoelectronic device controlling, for example, a contactor provided with an inverter replacing the inverter 52.
• the interchangeability of the filter 5 can be obtained by means of a disc or ribbon comprising filters of different colors which can be operated manually, from a remote control to whose control is programmable; the possible interchangeability of holes 6 of the cover 7 can also be obtained by means of a dis or tape with different holes.
• the miniature lantern can also be external to the slide projection apparatus using two synchronous motors coupled to an electric shaft actuating separately but simultaneously one ribbon 25 and the other a ribbon 27 or even be external to two such devices using three synchronous motors coupled to an electric shaft, one, controlled with one of the other two alternately, actuating separately but simultaneously a ribbon 25 and, before and after each coincidence of the windows of this ribbon 25, one of the other two one of two ribbons 27 in order, in this second case, to reduce the time separating the successive images of slides.
• the tape 25 could also move on the other side of the location for projecting the slides, the entire tape drive 25 and 27 then being located between this location and the objective 24.
• the filter 5 can be located elsewhere in the path of the light but preferably outside the depth of the field of sharpness to avoid dust images on the screen.
• a halogen lamp 1 of 10 or 20 watts is respectively sufficient.
• the transient lighting of the screen When the transient lighting of the screen is mechanically controlled, the light which is necessary for them can be taken from the unused radiation of the lamp for slide projections by means of a mirror inclined on the axis of the miniature lantern, the light source is then a virtual image of this lamp and the condenser 2 replaced by a lens of greater focal length. It seems that the transient illuminations of the screen are more pleasantly diffused if the rays coming from the condenser 2 eu of said lens are parallel.
• two additional lenses can, however, converge the two light beams, whose rays from the double prism 18 are parallel, on the objectives 3a and 3b; two separate miniature lanterns can also be used, obviously without double prism 18, each provided with a single objective 3 and producing half of the transient illumination of the screen, the windows 28a and 28b of the ribbon 25 being elongated by at least the width, corresponding to the thickness of the partition 19, of a cover on either side of which these windows 28a and 28b open and close.
• the lamp l can advantageously be switched on just before the removal of the projected slide by an advance control of the contactor 11 and simultaneous with that of the slide changing mechanism by inserting the diode 54 and possibly the diode 55 into the circuit of the switch 53 of these commands.
• the present invention can obviously also be applied to projections of views other than slides, both by episcopic and diascopic.
• Industrial application possibilities The design according to FIG. 1 and the descriptions which relate to it in particular allow the manufacture of accessories to advantageously complement existing slide projection apparatus.
• the design according to FIG. 2 and the descriptions which relate to it in particular make it possible to advantageously and easily supplement the models in the manufacture of slide projection apparatuses without having to increase either the power of their power transformer, the flow rate of their fan or their size.

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• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Projection Apparatus (AREA)

Applications Claiming Priority (6)

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• 1987
  • 1987-07-01 WO PCT/EP1987/000365 patent/WO1988000360A1/fr not_active Application Discontinuation
  • 1987-07-01 EP EP19870904688 patent/EP0313573A1/fr not_active Withdrawn
• 1988
  • 1988-07-01 CH CH162388A patent/CH672686A5/fr not_active IP Right Cessation

Non-Patent Citations (1)

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