Abstract:
This invention provides a system and method for projection of an image on any surface, employing a lightweight (typically polymer) housing that removably encloses a slide holder allowing for quick change of the slide. The housing includes a central channel, and allows for the mounting of a conventional camera-mounting-base lens at a front end and the insertion of a standard form factor photographic strobe/flash in the rear end. Light from the strobe passes down the channel, through the slide and is projected by the lens onto the surface. This housing is mountable on a standard tripod. The housing is straightforward to use, with the strobe effect being provided directly by the strobe unit. The system and method avoids the need of a camera body and desirably enables the user to employ one or more lenses, which are often less expensive and already available in a photographer&#39;s equipment inventory.

Description:
RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Application Ser. No. 61/750,375, filed Jan. 9, 2013, entitled SLIDE PROJECTOR HOUSING WITH MOUNT FOR DETACHABLE LENS AND STROBE, the entire disclosure of which is herein incorporated by reference. 
    
    
     FIELD OF THE INVENTION 
     This invention relates to photographic slide projectors, and more particularly to slide projectors that employ a conventional camera lens and strobe flash adapted for use with a camera hot shoe. 
     BACKGROUND OF THE INVENTION 
     The use of a slide projector to generate image effects on a surface, such as a wall, a ceiling, a screen or even a person, is often desirable. A variety of arrangements are available to provide such a projection. For example, a purpose-built slide projector can be employed. However, these units can be large, heavy and often do not lend themselves to portability or tripod mounting. In addition, they often lack the ability to provide a strobe effect. Published International Patent Application No. WO 2009/068524 A1, entitled DEVICE AND METHOD FOR PROJECTING A GRAPHIC REPRESENTATION ON A PROJECTION SURFACE, by von Bismarck, teaches a projection unit that mounts a slide at the back of a conventional single lens reflex (SLR) camera with a photographic strobe flash behind the slide. The camera then, in essence, acts in reverse, causing the light passed through the slide and lens to project as an enlarged image on the surface as the strobe and shutter are triggered. The lens can be focused to provide a sharp image on the surface. Likewise, where a zoom lens is fitted to the camera, the size of the image, relative to focal distance can be varied. 
     The arrangement of von Bismarck is effective, but requires a dedicated and often delicate/expensive SLR to be used to generate images. Where a plurality of images is to be projected or where the photographer cannot afford to dedicate one or more cameras to a projection task, von Bismarck is somewhat impractical. More generally, von Bismarck&#39;s structure requires one to remove the strobe to change the projected film, and is limited to the use of raw film with sprocket holes. Thus, von Bismarck is not adapted to project through other types of media, such as unframed transparencies, home-printed transparent materials and the like. 
     Thus, it is desirable to provide a system and method for allowing the stroboscopic projection of images onto a surface with appropriate focus and (optionally) zoom, that does not require an expensive fixed projection unit and/or camera body. This system and method should be easy to use, portable and tripod-mountable. It is further desirable that the projection system and method allow for a variety of transparent media to be projected-through, in addition to raw film, such as unframed transparency film and slices of transparencies produced, for example, using a home printer. 
     SUMMARY OF THE INVENTION 
     This invention overcomes disadvantages of the prior art by providing a system and method for projection of an image on a surface, which employs a lightweight (typically polymer) housing, that removably encloses a slide holder (clamshell) allowing for quick change of a framed slide (e.g. a plurality of slides/holders being available to the user). The housing includes a central channel, and allows for the mounting of a conventional (e.g. Canon 35 mm) camera-mounting-base lens at a front end and the insertion of a standard form factor photographic strobe/flash in the rear end. Light from the strobe passes down the channel, through the slide and is projected by the lens onto the surface. By way of example, the slide can conform to International Organization for Standardization (ISO) 1007 or another standard. In addition, the holder is sized and arranged to accommodate unframed slides and/or home-printed transparency media that can be free of sprocket holes. This housing arrangement is mountable on a standard tripod and/or light stand using a conventional female-threaded base thereon. The housing is straightforward to use, being free of any electrical connections and/or shutter mechanisms, with the strobe effect (if any) being provided directly by the strobe unit and/or other industry-standard triggering mechanisms. More particularly, a variety of transparent media can be readily installed in, and removed from, the holder free of the need to disassemble the strobe or lens from the overall assembly. The system and method further avoids the need of a dedicated camera body and desirably enables the user to employ one or more lenses, which are often less expensive and already available in a photographer&#39;s equipment inventory. 
     In an illustrative embodiment a system for a slide projection housing device with a mount for a detachable lens and strobe comprising a housing having a slot for a removably inserting a slide holder for a photographic slide; an aperture for removably inserting a strobe light; and an mounting base for removably attaching a lens. The strobe light projects light into the slide projection housing, the light passing through the photographic slide and the lens for projection as a projected image onto any surface. The projected image is projected onto a surface of a picture or other image to create a combined image for photography of the combined image by a photographer. The photographic slide is removably inserted into the slide holder and can be is placed into at least one of the faces of the slide holder and both faces are joined together. The first face includes alignment structures constructed and arranged to engage the corresponding alignment structures on the second face. At least one of the first face and the second face includes spring tabs that engage a portion of the slot under pressure. This provides a method for photographing an image wherein the image is projected from a slide housing comprising the steps of projecting, with a strobe light, a light into the slide housing along an optical axis; retaining a photographic slide so that light passes through the slide along the optical axis; and passing the light passing through the slide into a commercially available lens removably mounted on a mount of the housing so that light is focused at a predetermined size, focus and resolution on the surface. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention description below refers to the accompanying drawings, of which: 
         FIG. 1  is a perspective view of a slide projector housing with attached strobe and lens, mounted on a tripod and projecting an image for use by a photographer according to an illustrative embodiment; 
         FIG. 2  is an exploded perspective view showing the components of the slide projector housing, according to the illustrative embodiment; 
         FIG. 3  is a perspective view showing the attached components of the slide projector housing, according to the illustrative embodiment; 
         FIG. 4  is a cross section view of the slide projector housing taken along line  4 - 4  of  FIG. 2 , according to the illustrative embodiment; 
         FIG. 4A  is a cross section taken along line  4 A- 4 A of  FIG. 3 ; 
         FIG. 4B  is a more detailed, fragmentary cross section of the ratchet mechanism of the strobe compression plate assembly of  FIG. 4A ; 
         FIG. 5  is a close up cross section view of the slide projector housing taken along line  5 - 5  of  FIG. 2 , showing the slide holder, according to the illustrative embodiment; 
         FIG. 6  is a perspective view of a slide holder, according to the illustrative embodiment; 
         FIG. 7  is multi-sided perspective view of a slide holder, with a slide, according to the illustrative embodiment; and 
         FIG. 8  is a perspective view of a slide projector housing according to an alternate embodiment. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  depicts an illustrative slide projector housing device  100  with an attached exemplary strobe flash (also termed simply “strobe”)  102  and coaxially mounted camera lens  104  mounted atop a tripod or light stand  106 . The overall housing device assembly is shown projecting an exemplary image  108  (e.g. a stylized number “3”) onto a screen  110  that is provided with another image  112 , such as a picture/poster mounted on a wall, for photography. In operation, an exemplary photographer  114  is photographing the combined image  116 . The detachable strobe is a conventional commercially available strobe light. The detachable lens is also a conventional, commercially available camera lens that is connected to the front of the housing  100 . The projected image  108  falls within the field-of-view  118  of the photographer&#39;s camera  120 . The projected image  108  is derived from an image on an exemplary photographic slide (described more fully below) that resides within the body of the housing  100 . For the purposes of this description, the term “slide” should be taken broadly to include any transparent media through which light can pass to form an image and which is sized and arranged to be mounted within the holder  200  (described further below). Thus, the term can also include raw film segments (with or without (free of) sprocket holes), home-printed transparencies, and other appropriate media. The projected image  108  is created by the strobe  102  producing light that passes into the housing  100  and through the slide (not shown) that in turn passes through the lens  104  and is emitted directionally at the screen  110 . 
     The strobe  102  emits light in pulses. In an alternate embodiment, the light can be adapted to emit a more steady and sustained beam. The strobe can be provided with a variety of colors (for example using colored light sources, filters, etc.) in different visible (and/or invisible—IR for example) wavelengths that create different artistic effects for the projected image as required and desired by the photographer. The light intensity of the strobe can be arranged to vary between weaker to stronger light emission for the overall contrast of the projected image  108 . As noted above, the lens is a conventional 35 mm camera lens with a conventional SLR mounting base. The focus function on the lens can be used to sharpen or blur the projected image  108  by manual or remote manipulation. Likewise the lens&#39; aperture setting can be used to vary the image sharpness. It is contemplated that the lens focus can be changed automatically by a program and attached drive mechanism so as to vary the resolution of the projected image while the photographer  114  photographs the changing image effects. As described further below the housing arrangement is mountable on a standard tripod using a conventional female-threaded base situated thereon for connection to a threaded screw post, which is commonly employed on the conventional tripod  106  or similar mounting. 
       FIG. 2  is an exploded view of the housing  100  and the components that include the strobe  102 , the body of the housing  150 , the slide holder  200  and the lens  104 . The housing body  150  is opaque and is composed of relatively lightweight rigid materials, including natural and/or synthetic rigid polymers, metal alloys (e.g., aluminum) or a combination thereof. The housing body  150  has a weight of approximately 180 grams. The housing body  150  has an overall length OL of approximately 120 millimeters, an overall height OH of approximately 80 millimeters and an overall width OW of approximately 110 millimeters. The weight and dimensions can vary on the materials used, the size of the strobe and a different lens system. It is expressly contemplated that larger or smaller housings using appropriately sized components can be provided for use in different artistic applications as desired by the photographer. 
     The strobe  102  engages the housing by placing the emitting end  210  of the strobe into the strobe aperture  220 . The strobe  102  is then held in place by a frictional fit within the strobe aperture  220 . With reference also to  FIG. 4 , to seat the strobe  102 , the photographer inserts the front emitting end  210  into the strobe aperture  220  and pushes the strobe  102  until the strobe end  210  makes contact with the limiting wall  402  and the bottom side  224  of the strobe engages the housing bottom. With reference also to  FIGS. 4A and 4B , the top section  260  of the housing  150  includes a port  450  that allows a finger to press upon and/or observe the location of a compression plate assembly  452 . The compression plate assembly  452  is movable upwardly and downwardly (arrow  458 ) to allow the roof  460  of the compression plate assembly  452  to be brought into close engagement with the top surface  226  of the strobe  102  (as shown in  FIG. 4 ). This provides appropriate compression to retain the strobe in place. As shown, the compression plate assembly  452  includes side walls  470  that pass through slots  472  in the bottom of the housing  150 . The sidewalls  470  are captured between the side ribs  401 ,  403  that allow up/down sliding but restrain against front/rear motion. Each sidewall  470  includes a stylized bottom pull tab  474  that allows the user to elastically squeeze the walls toward each other (arrows  480 ), and move the plate assembly up and down. The slots  472  have sufficient clearance to allow the walls to move/flex a predetermined distance. As shown in  FIG. 4B , the compression plate assembly  452  is restrained at a predetermined elevation (in engagement with the strobe) by a ratchet assembly. The ratchet assembly consists of a series of saw tooth steps  482  formed along the outside of the sidewall  470 . The steps  482  selectively engage a pawl  484  at the outer edge of the slot  470 . The steps  482  are sloped to allow the compression plate assembly to be freely drawn downwardly against the pawl into an appropriate engagement with the strobe. After the selected step is engaged by the pawl, the compression plate assembly  452  can be released and moved upwardly by squeezing the tabs together (to disengage them from the pawl), and raising the assembly toward the top  260  of the housing. In embodiments, one or more locations along the aperture and/or compression plate can include an elastomeric material (e.g. rubber feet) that assists in frictionally retaining the strobe once the top section is compressed against it. In alternate embodiments other mechanisms can be used to secure the strobe within the housing. For example, a removable elastic strap can be used to engage the rear of the strobe body, and bias the strobe body forwardly into the aperture. Alternatively, a foam packing can be used against the roof to secure the strobe in place. 
     The coaxially mounted lens  104  is connected to the housing by appropriately sized threading  232  that are arranged according to conventional camera lens mounts that are based upon photography standards in the industry. In this embodiment the mount is standardized to a 35 mm digital SLR standard available from Canon of Japan. Other mount standards and lens sizes, such as those available from Nikon of Japan or Leica of Germany can be substituted in alternate embodiments. The lens threading  232  engages threading grooves (described more fully below) situated around the lens aperture  240  so that the locking end  230  of the lens is removably secured to the housing  100 . The slide holder  200  contains a changeable slide (not shown) and is inserted into the slide groove  252  located in the top of the housing  100 . The bottom edge  250  of the slide holder  200  is aligned with groove  252  and the slide housing is vertically placed within the housing. The bottom edge  250  is typically provided with a live hinge along the edge to join the respective faces. The slide holder  200  can be held in place by frictional fit, a locking mechanism or by gravity. It is expressly contemplated that the slide housing groove can be constructed in the side of the housing so that the slide holder  200  is inserted laterally. The slide holder  200  is aligned so that the slide is perpendicular to the axis of the path of the light LP (optical axis of the system). It is contemplated that the slide housing groove can be constructed for limited rotational movement away from the perpendicular orientation relative to the axis LP for different effects in the projected image. 
       FIG. 3  is a view of the components of  FIG. 2  as assembled and securely arranged for use as a projector. The strobe  102  as depicted is provided with an energy storage battery that is removable and/or rechargeable. It is contemplated that the photographer can use an optional power cable to connect the strobe  102  to a power source and/or the camera&#39;s external strobe trigger. In this manner the strobe is activated in synchronization with the shutter of the photographer&#39;s camera. This trigger link can be wired or wireless in various embodiments. As noted above, the lens can be manually or remotely focused so as to project a focused or blurred image. An appropriate attachment for driving lens focus, with associated control link would be used to auto-focus (and/or auto-zoom—where applicable) the lens. In general, for most applications, manual focus and manual zoom (where applicable) is sufficient. 
     It is also contemplated that removably attached light filters, polarizers and/or other light-conditioning devices can be attached to the front of the lens  302  to further alter the projected image. For example, an applied coating of an oil on the lens  302  to make the emitted image more diffuse, or a green filter to alter the image. It is further contemplated that a prismatic diffusion lens can be used to break up the projected image into a disarticulated artistically significant presentation. 
       FIG. 4  is a cross section view of the assembled projector of  FIG. 3 . The strobe is depicted as being frictionally held in place by the compressed top section, and has been directed forward into the strobe aperture  220  so that the front end  210  is in contact with the limiting wall  402  along the floor of the housing body  150 . The limiting wall  402  is constructed low enough so that light will pass unimpeded from the strobe  102 , and includes a pair of opposing side ribs  403  that extend upwardly from the wall  402 . Each side rib  403  (as well as the rear-most side rib  401 ) provides a sufficient side clearance for the strobe to be inserted and (in the case of front rib  403 ) for light to pass. 
     As also shown in  FIG. 4 , the lens  104  is secured by the engagement of the lens threads  232  with the threading of the receiving grooves  404  constructed around the inner perimeter of the centrally open lens aperture  230 . As also depicted in the cross section, the bottom side of the housing includes a threaded hole  420  within a raised base  422 . This hole  420  is threaded to receive a standard mounting post (e.g. a standard ⅜-16 internal thread). Other forms of mounting arrangements and multi-piece mounts are expressly contemplated—for example, a sub-base threaded to the tripod that removably attached by clips, etc. to the main housing. 
       FIG. 5  is a close-up image of the cross-section of  FIG. 4  and shows the detail of the slide holder  200 . The slide holder  200  defines a “clamshell” structure that is provided with two faces  504  and  506  enclosing a slide  502  with centrally located apertures  510 ,  512 . A slide  502  having a frame and a central transparent photographic image can been removably placed within the holder  200  and is secured by the engagement of the rear housing face  504  and the front housing face  506 . The slide  502  is comprised of a surrounding frame  516  and a captured image  518 . In an embodiment, the faces  504  and  506  are each two discrete halves of the overall slide holder  200 , which are placed together around a slide  502 . The faces  504 ,  506  of the slide holder  200  are adapted to be hinged apart, and a selected slide  502  or other transparent media (e.g. raw film, a printed transparency, etc.) is placed onto one of the faces and held therein until the opposing face is closed over it. In an embodiment, the top end of the holder includes a pair of overlapping, resilient lips that form a snap fit at a junction  530  on the upper side/edge of the holder  200 . It is further contemplated that, in an alternate embodiment, a live hinge is omitted and the housing faces can be formed as two discrete halves that are fully separated from each other to receive the slide or other media and are engaged together after the slide is installed therein. 
     The slide housing provides that light emitted by the strobe (not shown) following the axis of the light path LP passes through a centrally located opening  510  in the rear housing face  504 , the slide  502  and a centrally located opening  512  in the front housing face  506 . 
     The slide housing is depicted more particularly in  FIG. 6 . As noted above, the slide holder  200  can opened and closed by drawing the halved fully apart or by action of a live hinge. The apertures  510 ,  512  in the respective faces  504 ,  506  provide a window for the movement of projected light from the strobe (not shown) through the retained slide  502  and into the lens  104  (not shown in  FIG. 5 ) for projection. As noted above, the slide housing is comprised of two halves, faces  504 ,  506  that (in this embodiment) are removably attached by the engagement four (and at least two) semi-circular alignment tabs  520 . In the illustrative embodiment, the slide holder  200  is provided with four alignment tabs  520  on face  504 . In general, the alignment tabs  520  are sized and arranged to define a rail for the mounting of raw film and/or home-printed transparencies so that they are properly presented to the aperture of the holder. It is expressly contemplated that the slide housing can be provided with a greater or lesser number of alignment tabs than that depicted. The alignment tabs  520  are shown engaging opposing receiving wells  522  on face  506  to provide a continuous alignment structure. Also in an illustrative embodiment, the well that retains a framed slide can include unitarily molded spring tabs  620  on the face  504  that accommodate the variation in thickness that is sometimes encountered in differing slides. The tabs provide a slight biasing force against the thinnest slide expected to be mounted, and flex outwardly within their slots  622  to accommodate thicker slides. 
     As also shown in  FIG. 6 , a gap  630  is provided along each side of the holder (when fully closed) to accommodate a raw film piece or home-printed transparency between the tabs  520 . The spacing SF between tabs can be adapted to define a mounting rail sufficient for a standard-width film piece-such as 35 millimeter film. 
       FIG. 7  depicts the two slide housing faces  504 ,  506  in multi-view illustration (i.e. front and rear external sides). In operation, the slide  502  with an image  702  is positioned in an appropriate central aperture on one of faces  504 ,  506  (with the inner edge of the aperture sized and arranged to receive and seat the slide). The faces are then engaged together in alignment, so that the outer perimeter edge  704  of face  504  confronts the outer perimeter edge  706  of face  506 . The semi-circular alignment tabs  520  are sized appropriately for entering the respective receiving wells  522  as shown to create an aligned engagement between the joined faces  504 ,  506 . Face  506  is provided with two unitary (molded) spring tabs  708  defining a slight outward projection. These spring tabs  708  act as retaining springs when the slide holder  200  is engaged within the receiving slot of the housing. In particular, the spring tabs  708  are compressed when the slide holder  200  is placed into the slide groove  252  (described more fully above) within the housing  100 . The compression of the spring tabs  708  provides a secure fit within the housing  100  but allows for ready removal of the slide holder  200  with modest force by pulling on the raised portion  710 . The spring tabs also ensure that the two faces  504  and  506  remain in close engagement with each other when the holder  200  is mounted within the housing. 
       FIG. 8  is a perspective view of a slide projector housing device according to an alternate embodiment. For the purpose of simplification, this embodiment uses like reference numbers with respect to like elements of the embodiment described above. An optionally removable elastic strap mechanism  802  secures the strobe  102  (as shown in  FIG. 2 ) within the housing device  100 . The elastic strap can be made from any flexible material or combination of flexible materials, including rubber or plastic and woven textile. The elastic strap can include elastic webbing formed integrally with, or as a separate component from, the elastic material. 
     Depending on the materials used and prevailing market conditions, the strap mechanism can be less costly to manufacture, and repair or replace compared to some embodiments. The elastic strap comprises a continuous circular band, where the bottom portion extends through apertures  804  in a plate located in the base of the housing device  100  and is secured by fasteners. In an alternate embodiment, the elastic strap comprises two ends that are stitched or glued together to prevent fraying and secured to the bottom of the housing device  100  by one or more fasteners. In another alternate embodiment, the strap is separable above the emitting end of the strobe, and can be secured or tightened via hook and loop fasteners attached to the top of the band. Alternatively, buckles, buttons, other fasteners known in the art can be used. 
     The strap extends into the aperture far enough to substantially cover the sides of the emitting end of the strobe body. A friction inducing material can be added to the inside surface of the strap to provide a stronger hold around the emitting end of the strobe. The friction inducing material can be elongated stripes or a uniform coating, and can be comprised of rubber, a rubberized plastic, or a similar material. In alternate embodiments, the strap may extend further into the aperture to provide a more secure fit for some strobes. In another alternate embodiment, two or more parallel straps may be used to facilitate ventilation and strobes having a longer emitting end. In still other alternate embodiments, the strap may be thick, or comprise two or more bands on top of each other to provide additional hold and durability. 
     The strap mechanism  802  engages the rear of the strobe body, and can bias the strobe body forwardly into the aperture. The strap frictionally secures the strobe with precision, and is not limited to predetermined height increments. More particularly, the elastic strap fits securely around the top of the strobe at any height below the top  260  of the housing and pulls the strobe downwardly toward the base of the housing device  100  and forwardly into the aperture. 
     The foregoing has been a detailed description of illustrative embodiments of the invention. Various modifications and additions can be made without departing from the spirit and scope of this invention. Features of each of the various embodiments described above can be combined with features of other described embodiments as appropriate in order to provide a multiplicity of feature combinations in associated new embodiments. Furthermore, while the foregoing describes a number of separate embodiments of the apparatus and method of the present invention, what has been described herein is merely illustrative of the application of the principles of the present invention. For example, as used herein various directional and orientational terms such as “vertical”, “horizontal”, “up”, “down”, “bottom”, “top”, “side”, “front”, “rear”, “left”, “right”, and the like, are used only as relative conventions and not as absolute orientations with respect to a fixed coordinate system, such as gravity. As noted above, the projected image can be altered by use of filters, applied coatings, rotation of the projected image, less or more focus and greater or lesser light. The slide housing can be placed into the housing vertically or laterally. In other embodiments, the emitted image can be provided by pulsed light, varied strength or steady light. The combined image is thereby a variable synthesis of projection and light and can be efficaciously interpreted by the photographer so as to surpass the mere visual representation of image and become artistic expression. It is contemplated that one or more such slide projection systems can be combined for multiple images and artistic effects. Additionally, while the housing includes a lens mount adapted to a particular commercial mount standard, it is expressly contemplated that the housing can be provided with an industry standard (or customized) removable adapter or mount base (e.g. a clip-in mount base) that allows differing types of lenses/mounts to be employed with the same housing. It is further contemplated that an elastic strap mechanism may secure the strobe to the housing by reaching behind the strobe and pulling it toward the housing aperture. Accordingly, this description is meant to be taken only by way of example, and not to otherwise limit the scope of this invention.