Abstract:
A light fixture includes a light source, a first flexible material coupled to a first scrolling mechanism, and a second flexible material coupled to a second scrolling mechanism. The first flexible material includes a plurality of areas with different diffusion characteristics. The second flexible material includes a plurality of areas with different color filtering characteristics, such that at least part of the light from the light source passes through a first area having a first color filtering characteristic, and at least another portion of light from the light source passes through a second area having a second color filtering characteristic different from the first color filtering characteristic. The first flexible material blending the portions of light passing through the first and second areas.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present application is a continuation application that claims priority to U.S. patent application Ser. No. 12/357,247, entitled “Method and Apparatus for a Scrollable Modifier for a Light Fixture, ” filed Jan. 21, 2009, which is related to and claims priority to U.S. patent application Ser. No. 12/355,076, entitled “Pattern Generator for a Light Fixture, ” filed Jan. 16, 2009, which claims priority to U.S. Provisional Patent Application Ser. No. 61/011,557, entitled “Method and Apparatus for Controlling Diffusion and Color of a Light Beam,” filed on Jan. 18, 2008, all of which are assigned to the assignee of the present application. 
     The present application is related to and claims priority as a continuation-in-part of U.S. patent application Ser. No. 11/260,501, entitled “Method and Apparatus for Controlling Diffusion and Color of a Light Beam”, filed on Oct. 27, 2005, which claims priority to U.S. Provisional Patent Application Ser. No. 60/684,376, entitled “Method and Apparatus for Scrolling Diffuser,” filed on May 24, 2005, and U.S. Provisional Patent Application Ser. No. 60/695,154, entitled “Method and Apparatus for Scrolling Color Changer and Diffuser,” filed on Jun. 29, 2005. U.S. patent application Ser. No. 11/260,501, U.S. Provisional Patent Application Ser. No. 60/684,376, and U.S. Provisional Patent Application Ser. No. 60/695,154, are assigned to the assignee of the present application. 
     The subject matter disclosed in U.S. patent application Ser. No. U.S. Provisional Patent Application Ser. No. 61/011,557, U.S. patent application Ser. No. 11/260,501, U.S. Provisional Patent Application Ser. No. 60/684,376, and U.S. Provisional Patent Application Ser. No. 60/695,154, is hereby incorporated by reference into the present disclosure as if fully set forth herein. The present application hereby claims priority under 35 U.S.C. §120 to U.S. patent application Ser. No. and U.S. patent application Ser. No. 11/260,501. 
    
    
     TECHNICAL FIELD 
     The present invention relates to automated lighting equipment, and in particular, to an effects generator for a lighting fixture. 
     BACKGROUND 
     Traditionally, the spread or diffusion of a lighting fixture has been controlled by placing a lens, ground glass or other optical component in the path of light produced by the light source. The optical component may be made of glass, plastic or other suitable material. In order to control the amount of diffusion, the lens may be motorized and moved to different locations along the axis of the light path or moved relative to other optical components in the light path. Alternatively, a selection of lenses may be mounted on a wheel or semaphore arms to be placed into and removed from the light path. 
     Particularly where such lenses are positioned at the outlet, or mouth, of the fixture, their weight and the weight of mechanisms to move them may unbalance the head of the fixture. This imbalance may make an automated lighting fixture more difficult to move, causing overshoot when stopping or limiting the maximum speed at which the can be moved. 
     Lighting fixtures employing a parabolic or near-parabolic reflector emit a light beam comprised of substantially parallel light rays. As a result, when only a portion of the light beam emerging from the reflector is covered by a color filter, in an attempt to produce a light beam of variable saturation, some parts of the projected light beam are colored and the remainder is white. Similarly, when one portion of the light beam emerging from the reflector is covered by a first color filter and the remainder of the light beam is covered by a second color filter, in an attempt to produce a light beam of variable color, some parts of the projected light beam have the first color and the remaining parts have the second color. 
     SUMMARY 
     In one embodiment, a method includes scrolling a first flexible material that includes a first pattern generator from a first position to a second position in a beam of light from a light source of a light fixture. The method also includes scrolling a second flexible material that includes a second pattern generator to a third position in the beam of light. A changing pattern is produced in the beam of light. 
     In another embodiment, a light fixture includes a light source, a first flexible material coupled to a first scrolling mechanism, and a second flexible material coupled to a second scrolling mechanism. The first flexible material includes a first pattern generator and the first scrolling mechanism is operable to move the first pattern generator from a first position to a second position in a beam of light from the light source. The second flexible material includes a second pattern generator and the second scrolling mechanism is operable to move the second pattern generator to a third position in the beam of light. A changing pattern is produced in the beam of light. 
     In still another embodiment, an apparatus for use with a light source includes a first flexible material coupled to a first scrolling mechanism, and a second flexible material coupled to a second scrolling mechanism. The first flexible material includes a first pattern generator and the first scrolling mechanism is operable to move the first pattern generator from a first position to a second position in a beam of light from the light source. The second flexible material includes a second pattern generator and the second scrolling mechanism is operable to move the second pattern generator to a third position in the beam of light. A changing pattern is produced in the beam of light. 
     The foregoing has outlined rather broadly the features and technical advantages of the present invention so that those skilled in the art may better understand the detailed description of the invention that follows. Additional features and advantages of the invention will be described hereinafter that form the subject of the claims of the invention. Those skilled in the art should appreciate that they may readily use the conception and the specific embodiment disclosed as a basis for modifying or designing other structures for carrying out the same purposes of the invention. Those skilled in the art should also realize that such equivalent constructions do not depart from the spirit and scope of the invention in its broadest form. 
     Before undertaking the DETAILED DESCRIPTION below, it may be advantageous to set forth definitions of certain words and phrases used throughout this patent document: the terms “include” and “comprise,” as well as derivatives thereof, mean inclusion without limitation; the term “or,” is inclusive, meaning and/or; the phrases “associated with” and “associated therewith,” as well as derivatives thereof, may mean to include, be included within, interconnect with, contain, be contained within, connect to or with, couple to or with, be communicable with, cooperate with, interleave, juxtapose, be proximate to, be bound to or with, have, have a property of, or the like; and the term “controller” means any device, system or part thereof that controls at least one operation, such a device may be implemented in hardware, firmware or software, or some combination of at least two of the same. It should be noted that the functionality associated with any particular controller may be centralized or distributed, whether locally or remotely. Definitions for certain words and phrases are provided throughout this patent document, those of ordinary skill in the art should understand that in many, if not most instances, such definitions apply to prior uses, as well as to future uses, of such defined words and phrases. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       For a more complete understanding of the present invention, and the advantages thereof, reference is now made to the following descriptions taken in conjunction with the accompanying drawings, wherein like numbers designate like objects, in which: 
         FIG. 1  shows a schematic view of an automated lighting fixture in accordance with the invention; 
         FIG. 2  is a back view of a scrolling mechanism for use in the light fixture of  FIG. 1 ; 
         FIG. 3  shows color and diffusion strings that may be used in the embodiment of the invention shown in  FIG. 1 ; 
         FIGS. 4-6  are schematic illustrations of the operation of the embodiment of the invention shown in  FIG. 1 ; 
         FIGS. 7 and 8  depict pattern generators that may be used in an embodiment of the invention; 
         FIG. 9  shows another automated lighting fixture in accordance with the invention; 
         FIG. 10  depicts a color string that may be used in the embodiment of the invention shown in  FIG. 9 ; 
         FIG. 11  shows another embodiment of the invention; 
         FIGS. 12A-C  depict a flexible diffusion material frame for use with the embodiment of the invention shown in  FIG. 11 ; 
         FIG. 13  is a back view of a scrolling mechanism in accordance with the invention for use in the light fixture of  FIG. 9  or  FIG. 11 ; 
         FIG. 14  is a schematic illustration of the operation of the scrolling mechanism shown in  FIG. 13 . 
     
    
    
     DETAILED DESCRIPTION 
       FIGS. 1 through 14 , discussed below, and the various embodiments used to describe the principles of the present invention in this patent document are by way of illustration only and should not be construed in any way to limit the scope of the invention. Those skilled in the art will understand that the principles of the invention may be implemented in any suitably arranged wireless communications network. 
       FIG. 1  shows a schematic view of an automated lighting fixture in accordance with the invention. A lamp  102  is mounted near the focal point of a parabolic or near-parabolic reflector  104 . Scrolling mechanisms  106 ,  108  and  110  are mounted across the outlet aperture of the parabolic reflector  104 . In this position, the flexible material carried by the scrolling mechanisms  106 ,  108  and  110  intercepts light rays  112 A-C emitted by the bulb  102 . The light ray  112 A passes directly from the bulb to the mouth of the lighting fixture  100 , while the light rays  112 B and  112 C reflect from the reflector  104  before emitting from the mouth of the lighting fixture  100 . 
     The flexible material carried by the scrolling mechanism  110  may be flexible diffuser material in accordance with the invention. The flexible material carried by the scrolling mechanisms  106  and  108  may be color filter material. The color filter material may be fabricated as a dichroic filter, which has the benefit that substantially all light at frequencies not passed by the filter are reflected, rather than absorbed. As a result, the filter material stays cooler and requires less frequent replacement. Alternatively, the color filter material may be fabricated from conventional color gels. 
     While lighting fixture  100  is depicted with a parabolic reflector, it will be understood that a scrolling diffuser according to the invention may also be used with a light fixture having an elliptical reflector or no reflector at all. Similarly a scrolling diffuser according to the invention may be used with a light fixture having any type of light source: e.g., LED, filament or arc source. A light fixture according to the invention may be used, for example, in theatrical, concert, motion picture, and architectural lighting applications. 
     The flexible diffuser material used in scrolling mechanism  110  may be a holographic diffuser, such as LSD® Light Shaping Diffuser Film, manufactured by Physical Optics Corporation of Torrance, Calif. A light-shaping diffuser film may be an array of microlenses imprinted on a surface of a flexible film, typically polyester or polycarbonate. The microlenses diffuse light passing through the array in a pre-determined angle. Other flexible diffusion material may additionally or alternatively be used without departing from the spirit and scope of the invention. 
       FIG. 2  presents a back view of a scrolling mechanism  200  suitable for use in the light fixture of  FIG. 1  as scrolling mechanism  110 . A housing  202  may provide mechanical support for components of the scrolling mechanism  110 . An aperture  204  in the housing  202  allows a light beam from the light source  102  (including light rays  112 A-C) to pass through the housing  202  and a flexible diffusion material  210 . 
     The diffusion material  210  is wrapped at opposite ends around rollers  206  and  208 . A motor  212  drives the roller  206  via a belt  214  and pulleys  216  and  218 . The roller  208  may be spring loaded to maintain the diffuser material  210  in tension between the rollers  206  and  208 . The motor  212  may be remotely controlled by techniques known the person of skill in the art to wrap or unwrap the diffusion material  210  around the roller  206  in order to position a desired area of the diffusion material  210  across the aperture  204  and, thus, across the light beam from light source  102 . 
       FIG. 3  illustrates color filter and diffusion material (or strings) that may be used in the scrolling mechanisms of the lighting fixture  100 . Color filter strings  306  and  308  may be installed in the scrolling mechanisms  106  and  108 , respectively. Diffusion string  310  may be installed in the scrolling mechanism  110 . In a manner to be described with regard to  FIGS. 4-6 , the scrolling mechanisms  106  and  108  may be operated to position selected areas of the color filter strings  306  and  308 , respectively, and the scrolling mechanism  110  may be operated to position a selected area of the diffusion string  310 , across the outlet of the reflector  104 , in the light beam from the light source  102  and the reflector  104 . 
     The color filter string  306  is illustrated as having panels A-M. The panels A and M comprise leader material, used to attach the color filter string  306  to the rollers of the scrolling mechanism  106 . The panels C, E, G, I and K comprise clear material, which does not color the light beam from the light source  102 . The panels B, D, F, H, J and L comprise filter material of different colors. For example, the panels B, D, F, H, J and L may comprise red, green, blue, cyan, yellow and magenta filters, respectively. The panels B-L are substantially square, having vertical and horizontal dimensions substantially equal to (or slightly larger than) the diameter of the mouth of the reflector  104 . In this way, the scrolling mechanism  106  may be operated to position any of the panels B-L completely across the mouth of the reflector  104 , with the result that the light beam from the light source  102  is completely colored or uncolored. 
     In the alternative, scrolling mechanism  106  may be operated to position any desired area of color filter string  306  across the mouth of the reflector  104 . For example, a portion of a colored panel (e.g., the panel F) and a portion of an adjacent clear panel (either the panel E or G) may be positioned across the mouth of reflector  104 . In this way, part of the light beam will be colored and the remainder will remain uncolored. 
     Color filter string  308 , as shown, may be fabricated in a fashion similar to the color string  306 . Likewise, scrolling mechanism  108  may be used to position any desired area of color filter string  308  across the mouth of reflector  104 . In this way, any desired colored or clear section (or portions thereof) from color filter string  306  and any desired colored or clear section (or portions thereof) from color filter string  308  may be combined in the beam of light emerging from reflector  104 . In a manner to be described with regard to  FIGS. 4-6 , this provides control of the color and saturation of the light beam produced by lighting fixture  100 . 
     The color strings  306  and  308  of  FIG. 3  illustrate distinct boundaries between panels that are perpendicular to the sides of the color strings. It will be understood, however, that other boundaries between panels may be used without departing from the spirit and scope of the invention. For example, a diagonal boundary or a sawtooth edge to a panel may be used. 
     Indeed, either of the color strings  306  and  308  may be fabricated without distinct boundaries at all. A gradual transition between an area of color filter and a clear area (or between adjacent areas having different color filters, as will be shown with regard to  FIG. 10 ) may, for example, be fabricated as a pattern of disjoint regions of clear material, interspersed with conjoined regions of color filter material. The density of clear regions may increase until, at some point, the regions of clear material become conjoined and the regions of color filter material become disjoint. The density of color filter regions may then decrease until the gradual transition from color filter to clear is complete. It will be understood that other techniques known in the art may be used to produce gradual transitions from colored to clear, or from one color to another color. 
     Diffusion/pattern string  310  is illustrated as having panels N-Z. The panels N and Z comprise leader material, used to attach the diffusion/pattern string  310  to the rollers of the scrolling mechanism  110 . The panels O-T may comprise, for example, holographic lens material such as the LSD® Light Shaping Diffuser Film, manufactured by Physical Optics Corporation of Torrance, Calif. The panels O-R may comprise material selected to provide a graduated sequence of increasing omni-directional diffusion, producing round beams of increasing degrees of divergence. The panels S and T may comprise material providing differing amounts of divergence in the horizontal and vertical directions, producing rectangular beams of differing degrees of divergence. 
     One or more of the panels V-Y may comprise “color correction” color filter material chosen to correct the color temperature of the bulb  102  as required for video or film lighting. Other ones of the panels V-Y may comprise pattern-generating material. This material may comprise selected portions of opaque or colored materials bonded to a clear substrate. When such a pattern generator is placed across the mouth of the reflector  104 , a light beam with a pattern of white and dark or colored segments is produced. Panel U may comprise clear material that produces neither diffusion nor a pattern, thereby passing the light beam with substantially parallel light rays, as produced by the parabolic reflector  104 . 
     Thus, the scrolling mechanism  110  may be operated to position any of the panels O-Y across the mouth of the reflector  104 . The panels O-T, as described, may operate to integrate a partially colored light beam produced by the scrolling mechanisms  106  and  108 , and to diffuse the light beam to a predetermined degree of divergence. The panel U, as described, may leave the light beam unchanged as it passes through the scrolling mechanism  110 . The panels V-Y, as described, may operate to color correct the light beam or to introduce a pattern in the light beam. 
     As described with regard to the color strings  306  and  308 , the diffusion/pattern string  310  may be fabricated with transitions between panels other than the distinct, perpendicular boundaries shown in  FIG. 3 . Such gradual transitions or non-perpendicular boundaries may operate to smooth the change from one amount of diffusion to another or from one pattern to another. As will be described with regard to  FIG. 8 , a single pattern may in fact extend across an area of the diffusion/pattern string  310  that is the size of two or more panels, as shown in  FIG. 3 . 
       FIGS. 4-6  illustrate the embodiment of the invention shown in  FIG. 1  in operation. In  FIG. 4 , scrolling mechanisms  406 ,  408  and  410  are analogous to scrolling mechanisms  106 ,  108  and  110 , respectively. Scrolling mechanisms  406  and  408  operate to position color filter strings across light beam  420  and scrolling mechanism  410  operates to position a diffusion/pattern string across the light beam. 
       FIG. 4  illustrates the ability of an embodiment of the invention to mix colors additively, and to control the color and saturation of the light beam individually. A scrolling mechanism  406  has been operated to position red filter material (portion  406 A) across part of a white light beam  420 , and clear material (portion  406 B) over the remainder of the light beam  420 . As a result, a part  422  of the light beam is colored red, while a part  424  remains white. 
     Scrolling mechanism  408  has been operated to position clear material (portion  408 A) to cover the part  422  of the light beam, and blue filter material (portion  408 B) over the part  424  of the light beam. As a result, a part  426  of the light beam remains red, while a part  428  of the light beam is now blue. Scrolling mechanism  410  has been operated to position diffusion material across the light beam, resulting in the blending of the red and blue parts of the light beam into a magenta light beam  430 . 
     Were the scrolling mechanisms  406  and  408  to be operated in conjunction to increase the part of the light beam covered by the portions  406 A and  408 A, thereby decreasing the part of the light beam covered by the portions  406 B and  408 B, the result would be a change in the color of the light beam  430 . The color of the beam would have more red and less blue, resulting in a rose color. Alternatively, if the part of the light beam covered by the portions  406 A and  408 A were decreased and the part covered by the portions  406 B and  408 B were correspondingly increased, the light beam  430  would have more blue and less red, resulting in a lavender color. Thus, the scrolling mechanisms  406  and  408  may be operated to change the color of the light beam produced by the lighting fixture  100 . 
     In the alternative, the scrolling mechanism  406  may be operated to position clear material completely across the white light beam  420 . In this circumstance, both the portions  406 A and  406 B would comprise clear material, and both the parts  422  and  424  of the light beam would remain white. If the scrolling mechanism  408  were again to position clear material (the portion  408 A) over part of the light beam and blue filter material (the portion  408 B) over the remainder of the light beam, then the part  426  of the light beam would remain white while the part  428  of the light beam would be blue. The diffusion material positioned over the beam by the scrolling mechanism  410  would then integrate the multi-colored light beam, and the light beam  430  would have a pale blue color. 
     If the scrolling mechanism  408  were operated to position more or less of the blue filter material  408 B across the beam, the result would be, respectively, a more or less saturated blue color in the light beam  430 . Thus, the scrolling mechanisms  406  and  408  may be operated to change the saturation of the light beam produced by the lighting fixture  100 . 
       FIG. 5  illustrates the ability of an embodiment of the invention to control the color and saturation of the light beam together. A scrolling mechanism  506  has been operated to position red filter material (portion  506 A) over part of a white light beam  520 , and clear material (portion  506 B) over the remainder of the white light beam  520 . As a result, a part  522  of the light beam is colored red, while a part  524  remains white. 
     A scrolling mechanism  508  has been operated to position clear material (section  508 A) to cover the part  522  and a subpart of the part  524  of the light beam, and blue filter material (section  508 B) over the remainder of the part  524  of the light beam. As a result, a portion  526  of the light beam remains red, a portion  528  of the light beam remains white, and a portion  530  of the light beam is blue. 
     A scrolling mechanism  510  has again been operated to position diffusion material across the light beam, resulting in the blending of the red, white and blue portions of the light beam into a pale magenta light beam  532 . The inclusion of white light, along with the red and blue portions of the beam, produces a less saturated color than that produced by the configuration shown in  FIG. 4 . 
     As described with regard to  FIG. 4 , the scrolling mechanisms  506  and  508  may be operated independently or in conjunction to control the relative sizes of the parts  526 ,  528  and  530 . By so doing, more or less red, white and blue light may be mixed in the light beam  532  to produced a more or less saturated color and to produce a color ranging from rose through magenta to lavender. Thus, the scrolling mechanisms  506  and  508  may be operated to concurrently change the color and saturation of the light beam produced by lighting fixture  100 . 
       FIG. 6  illustrates the ability of an embodiment of the invention to mix colors subtractively, and to control the color and saturation of the light beam either individually or concurrently. A scrolling mechanism  606  has been operated to position magenta filter material (section  606 A) over a part of a white light beam  620 , and clear material (section  606 B) over the remainder of the light beam  620 . The magenta filter removes green, passing red and blue, so a part  622  of the light beam is colored magenta, while a part  624  of the light beam remains white. 
     A scrolling mechanism  608  has been operated to position yellow material (section  608 A) to cover the part  622  of the light beam, and clear filter material (section  608 B) over the part  624  of the light beam. The yellow filter removes blue, passing green and red. Because the part  622  of the light beam has only red and blue in it, after passing through the yellow filter, a part  626  of the light beam is red. A part  628  of the light beam remains white. A scrolling mechanism  610  has again been operated to position diffusion material across the light beam, resulting in the blending of the red and white portions of the light beam into a pale red light beam  630 . 
     The saturation of the light beam  630  may be controlled by operating the scrolling mechanism  606  to position more or less of the magenta filter  606 A across the white light beam  620 , thereby passing less or more white light, respectively. If the scrolling mechanism  608  is operated in conjunction to continue covering all of the part  622  of the light beam with the yellow filter  608 A, the blended light beam  630  will remain red, while increasing or decreasing in saturation, respectively. 
     In the alternative, if the scrolling mechanism  608  is operated independently to cover only a subpart of the part  622  of the light beam with the yellow filter  608 A, then a three part light beam will be created. The portion of the light beam passing through both the magenta and yellow filters will contain only red light, the portion passing through only the magenta filter will contain red and blue light, and the portion passing through neither filter will remain white. The scrolling mechanisms  606  and  608  may thus be operated independently to include desired relative amounts of red, blue and white light in the blended light beam  630 . As described with regard to  FIG. 5 , the color and saturation of the light beam produced by lighting fixture  100  may thus be controlled. 
     While additive color mixing has been illustrated by combining red and blue light, and subtractive color mixing by combining magenta and yellow filters, it will be understood that any combination of the standard RGB additive colors may be used in additive color mixing, or any combination of the CYM subtractive colors in subtractive color mixing without departing from the spirit and scope of the invention. Furthermore, hybrid colors may be created by using filters from the RGB set in subtractive combination with filters from the CYM set, or by using filters from the CYM set in additive combination with filters from the RGB set. For example, the blue filter from the RGB set could be used subtractively with magenta from the CYM set to produce a very deep near-ultraviolet color. Alternatively, a broad range of pinks and roses may be created by using the magenta filter from the CYM set, abutted with the red filter from the RGB set, and moving them together in inversely varying percentages of the two filters. 
       FIG. 7  depicts a pattern generator  700  for use with an embodiment of the invention. Sections  704  may be fabricated on clear substrate  702  by applying a reflective Mylar material to clear gel material. In this way a beam ‘broken up’ by 12 dark segments is formed. While separate opaque sections  704  are shown in  FIG. 7 , in another embodiment, a sheet of reflective Mylar the same size as clear substrate  702  may be fabricated with cutouts  704  and bonded to the substrate  702 . In this way a beam made up of 12 light segments could be formed. 
     In still other embodiments of a pattern generator according to the embodiment of  FIG. 7 , a light-shaping diffuser film may be used as the substrate  702 . The diffusing effect of the film&#39;s microlenses may be “defeated” by applying an optically transparent or translucent viscous material to the imprinted (or “textured”) side of the film in sections  704 . The viscous material fills the impressions of the microlenses and allows substantially undiffused transmission of the light beam at that point. Application of adhesive-backed clear films, therefore, results in the defeating of the lensing wherever contact of the film and adhesive is made. The result is that optically clear patterns may be created in the light-shaping diffuser substrate by applying an adhesive-backed film in a desired pattern. Examples of such a film are clear Mylar and colored gels. Such films may be self-adhesive or may have an adhesive material applied to one side prior to application to the light-shaping diffuser. The resulting effect is a pattern of substantially undiffused beams being projected within an otherwise lensed and diffused beam. 
     In any of these embodiments shown in  FIG. 7 , patterns may be colored by inserting or adhering one or more color filter films to the substrate. These may be absorptive color filters such as theatrical gel or may be other color filters, such as dichroic films. Colored filters may be used to fill clear spaces in an opaque pattern, to insert colored patterns into an otherwise clear beam, to produce undiffused colored areas within an otherwise diffused beam, as the scroll substrate to color all light passing through the gobo pattern, or in any combination of these options. 
       FIG. 8  shows pattern generator  800 , covering several adjacent panels—for example, the panels V-Y of the diffusion/pattern string  310  described with regard to  FIG. 3 . In this example, patterns are cut from thin mirror-reflective Mylar with the cutouts  804  representing the positive (light) desired beam shape and the Mylar surface  802  representing the negative (dark) pattern which is to occlude a desired portion of the light beam. The Mylar is then bonded to a predetermined number of sequential panels of the diffusion/pattern string  310 . The scrolling mechanism  110  may then be operated to position any predetermined area of the pattern generator  800  across the mouth of the reflector  104 , thereby producing a light beam from the light fixture  100  having a desired pattern. 
     Alternatively, the scrolling mechanism  110  may be operated to scroll the diffusion/pattern string  310  back and forth between the panels V and Y, that is, back and forth across the pattern generator  800 . Such continuous scrolling of the pattern generator  800  across the mouth of the reflector  104 , would produce a light beam from the light fixture  100  having a changing, or animated, pattern. 
     The diffusion/pattern string  310  creates variations within a projected beam, either by occluding a portion of the beam so as to produce a projected pattern, by coloring portions of the beam to produce a multicolored projection, or by varying the optical qualities of the beam by varying the diffraction of the beam in a pattern. 
     By scanning the diffusion/pattern string  310  back and forth across the mouth of a parabolic or near-parabolic reflector  104 , an operator can cause the patterns created by the string  310  appear to move within the field of projected light. The operator can vary a speed of this effect by varying a speed at which the scroll is driven. The operator may also produce flickering images by using these patterns in combination with a stationary pattern generator or when scanned in the opposite direction of, or at a different speed than, another diffusion/pattern string on a separate scrolling mechanism. 
     When used in a parabolic reflector system, properties of that optical system may result in a non-linear projection of the pattern of the diffusion/pattern string  310 . Images at extreme ends of the axis of motion are distorted into a sharp curve, which “straightens out” as the pattern approaches the center of the beam, then again distorts as it traverses the beam further. By scanning the diffusion/pattern string  310  back and forth across the mouth of a parabolic or near-parabolic reflector  104 , an operator can produce a “wrapping” effect in the pattern. An operator may also cause the appearance of a circular motion by placing a stationary pattern generator in a fixed position in a light beam and scanning the string  310  in the same beam. 
     With regard to the pattern generators  700  and  800  shown in  FIGS. 7 and 8 , the clear gel substrate to which the pattern is bonded may be replaced by a single color filter or may be a clear material with mosaic color sections applied at a desired cutout (positive) section or sections of the pattern, thereby producing a multicolored beam. Other materials than reflective Mylar may additionally or alternatively be used to form the pattern generators. Partially reflective material may be used to produce patterns with gray segments, rather than solely light or dark segments. 
     While pattern generators have been described with regard to  FIGS. 3 ,  7  and  8  as being installed on the scrolling mechanism  110  of the light fixture  100 , it will be understood that pattern generator panels may be installed additionally or alternatively on the scrolling mechanism  106  or  108 . In this way, color, pattern, and diffusion panels may be used together in a desired combination. 
     Another embodiment of the invention is illustrated in  FIG. 9 . As in the embodiment shown in  FIG. 1 , a light fixture  900  may include a light source  902 , mounted substantially at the focus of a parabolic reflector  904 . Light rays  912 A-C emitted by the light source  902 , emerge from the mouth of the reflector  904  substantially parallel to each other. A scrolling mechanism  908  carries a color filter string shown in  FIG. 10 . A scrolling mechanism  910  carries a diffusion string such as diffusion/pattern string  310 . 
     A color filter string  1000 , shown in  FIG. 10 , may be used with the embodiment of the invention shown in  FIG. 9 . Panels  1002  and  1004  of leader material may be used to attach the color filter string  1000  to the rollers of the scrolling mechanism  908 . Panel CLR may contain clear filter material, to allow the light fixture  900  to emit a white beam of light. Panels CC 1  and CC 2  may be color correction filters to appropriately color the beam of light for use in video or film applications. Panels C 1 -C 5  may be color filter material of different colors. 
     If the scrolling mechanism  908  is operated to position the color filter string  1000  so that the panel C 1  completely covers the mouth of the reflector  904 , the beam of light from the light fixture  900  will be the color of the color filter material comprising the panel C 1 . The scrolling mechanism  910  may then be operated to position a desired area of the diffusion material it carries across the light beam to cause a desired amount of diffusion in the light beam. As the scrolling mechanism  908  is subsequently operated to move the panel C 1  out of the light beam and the panel C 2  into the beam, the color blending effect of the diffusion material will cause the color of the light beam to smoothly change from the color of the panel C 1  to the color of the panel C 2 . 
     As will be understood, a light fixture according to the invention may have only a single scrolling mechanism, carrying a flexible material. The flexible material may be solely a diffusion material, where different areas of the material produce different amounts of diffusion in the light beam from the light fixture. Alternatively, the flexible material may also include other areas that additionally or alternatively cause color filtration of the light beam. 
     Similarly, a light fixture according to the invention may have a fourth scrolling mechanism. The flexible material carried by this mechanism may include only pattern generating panels, for combination with one scrolling mechanism carrying only diffusion material and two other scrolling mechanisms carrying only color filter material. Other combinations of flexible diffusion, color filter and pattern generating material carried by a scrolling mechanism may also be envisioned within the spirit and scope of the invention. 
     In addition, while the scrolling mechanisms of the light fixtures shown in  FIGS. 1 and 9  have their rollers located on the same sides of the light beam, it will be understood that a scrolling mechanism may be rotated 90 degrees around the longitudinal axis of the light beam. Additionally, the flexible diffusion or color filter material might be wrapped around the rollers to extend between the sides of the rollers closest to the light source, as shown in the scrolling mechanism in  FIG. 11 . In this way, the rollers of two scrolling mechanisms might be positioned to lie in the same plane, thereby reducing the length of a light fixture in accordance with the invention. 
     While scrolling mechanisms have been shown herein for causing color filtration of the beam of light emitted by a light fixture according to the invention, it will be understood that other mechanisms for selectively filtering the light beam to a predetermined color may also be used without departing from the spirit and scope of the invention. For example, the light fixture may include a wheel with separated segments having different color filters, mounted such that the light beam emerging from the reflector passes through a desired segment of the wheel before passing through the flexible diffusion material. 
     Yet another embodiment of the invention is shown in  FIG. 11 . A light fixture  1100  includes a light source  1102  mounted in a reflector  1104 . The housing of the light fixture  1100  extends beyond the mouth of the reflector  1104 , enclosing a scrolling mechanism  1106  and forming mounting brackets  1112 . A diffusion device  1110  is removably mounted to the light fixture, in this embodiment, by sliding the material into the mounting brackets  1112 . 
     Alternatively, the scrolling mechanism  1106  may be placed in a separate housing, as shown in  FIG. 2 , and the housing mounted to the light fixture  1100 . In such an embodiment, the diffusion device  1110  could be removably mounted to the housing of the scrolling mechanism  1106 . While the embodiment of the invention shown in  FIG. 11  provides for removably mounting the diffusion device  1110  to the light fixture  1100  by sliding it into the mounting brackets  1112 , other techniques may be used instead, such as quick release fasteners or screws. 
     The scrolling mechanism  1106  may carry flexible material including clear material, color filters, or pattern generators. The diffusion device  1110  may be a holographic diffuser, however in this embodiment of the invention, the material need not be flexible. 
     If the scrolling mechanism  1106  carries flexible material including clear material and color filters, it may be positioned, as described with regard to  FIGS. 4-6 , to produce a light beam having portions of different colors, or having a white portion and a colored portion. In such a case, the diffusion device  1110  will operate to blend the differently colored portions of the light beam. In this way, the embodiment of the invention shown in  FIG. 11  is capable of producing a uniformly colored light beam having a desired color or saturation. 
       FIGS. 12A-C  illustrate a mounting apparatus  1200  for use with the embodiment of the invention shown in  FIG. 11 , where the diffusion material is flexible. A frame  1202  has an aperture  1204  to permit passage of the light beam from the light source  1102  and the reflector  1104 . Held within the frame  1202 , and extending across the aperture  1204 , is flexible diffusion material  1206 . Brads  1208  may be used to secure the frame  1202  and the diffusion material  1206  together. 
       FIG. 12A  presents a front view of the apparatus  1200 , while  FIGS. 12B and 12C  show top views of the apparatus in open and closed configurations, respectively. In  FIG. 12B  it is clear that the frame  1202  may have two parts, attached to each other along one edge by a hinge. When the frame parts are spread apart, as shown in  FIG. 12B , the diffusion material  1206  may be placed between the parts. Once the frame parts are closed together, they capture the diffusion material  1206  between them. 
     The frame parts may remain in the closed position through the action of the hinge or other closure force. Friction between the frame parts and the diffusion material  1206  may be enough to prevent the diffusion material  1206  from slipping out of the frame  1202 . Alternatively, one or more brads  1208  may be placed through the frame  1202  and the diffusion material  1206 , to hold the frame parts together or to prevent the diffusion material  1206  from slipping out of the frame  1202 . 
     The diffusion device  1110  may comprise a frame and diffusion material, even if the diffusion material isn&#39;t flexible. For example, if the diffusion material is delicate or brittle, a frame may be used to allow the diffusion material to be inserted and removed from the mounting brackets  1112  without damaging the diffusion material. Similarly, other mechanisms than the frame  1202  may be used to support the flexible diffusion medium  1206 , such as a casing that holds the medium in tension or a clear, non-flexible panel upon which the flexible diffusion medium  1206  is mounted. 
     With the embodiment of the invention shown in  FIG. 11 , multiple diffusion devices  1110  may be prepared with diffusion material producing different amounts of diffusion in the light beam. In this way, a diffusion device  1110  may be selected and mounted to the light fixture  1100  in order to produce a desired amount of diffusion. 
       FIG. 13  shows an alternative color scrolling device  1300  for use in place of the scrolling mechanism  908  of the light fixture of  FIG. 9  or the scrolling mechanism  1106  of the light fixture of  FIG. 11 . As described with regard to the scrolling mechanism  200 , shown in  FIG. 2 , a housing  1302  may provide mechanical support for components of two scrolling mechanisms  1300 A and  1300 B, and an aperture  1304  allows a light beam to pass through the housing  1302  and color filter material  1310 A and  1310 B. 
     In the scrolling mechanism  1300 A, the color filter material  1310 A is wrapped at opposite ends around rollers  1306 A and  1308 A. As described with regard to the scrolling mechanism  200 , a motor  1312 A drives the roller  1306 A while the roller  1308 A maintains the color filter material  1310 A in tension between the rollers  1306 A and  1308 A. The motor  1312 A may be operated to position a desired area of the color filter material  1310 A across the upper half of the aperture  1304 . Similarly, in the scrolling mechanism  1300 B, color filter material  1310 B is wrapped at opposite ends around rollers  1306 B and  1308 B, and a motor  1312 B drives the roller  1306 B to position the color filter material  1310 B across the bottom half of the aperture  1304 . 
     In the color scrolling device  1300  shown in  FIG. 13 , a gap  1320  exists between the adjacent edges of the color filter materials  1310 A and  1310 B. The gap  1320  will allow white light to pass through the aperture  1304  even when both the color filter materials  1310 A and  1310 B are positioned so as to fully color their respective halves of the aperture  1304 . In an alternative scrolling device, the rollers carrying the two pieces of color filter material might be offset relative to each other to reduce or eliminate the gap  1320 . In another alternative, a strip of opaque material might be placed across the aperture  1304  to block the white light passing through the gap  1320 . 
       FIG. 14  illustrates the ability of the color scrolling device  1300  of  FIG. 13  to mix colors additively and to control the color and saturation of the light beam together, or to control the saturation of the color independently. The motor  1312 A has been operated to position red filter material (portion  1422 ) over part of the aperture  1304  and clear material (portion  1424 ) over the remainder of the aperture  1304 . Likewise, the motor  1312 B has been operated to position blue filter material (portion  1428 ) over part of the aperture  1304  and clear material (portion  1426 ) over the remainder of the aperture  1304 . As a result, a portion of the light beam is read, another portion blue, and the remainder remains white. 
     If diffusion material has been positioned across the light beam after it passes through the color scrolling mechanism  1300 , for example by scrolling mechanism  910  of  FIG. 9  or by diffusion device  1110  of  FIG. 11 , the red, white, and blue portions of the light beam will be blended into a pale magenta light beam. If the motor  1306 A is operated to increase the size of portion  1422 , while portions  1426  and  1428  remain unchanged, thereby increasing the amount of red filter material and decreasing the amount of white light in the beam, the resulting color of the beam will move towards a rose color and become more saturated. Similarly, if the motor  1306 B is operated to increase the size of portion  1428 , while portions  1422  and  1424  remain unchanged, thereby increasing the amount of blue filter material and decreasing the amount of white light in the beam, the resulting color of the beam will move towards a lavender color and become more saturated. 
     If the motors  1306 A and  1306 B are operated in conjunction to simultaneously increase or decrease the sizes of portions  1422  and  1428 , respectively, the color of the light beam will remain magenta while increasing or decreasing in saturation. Thus the motors  1306 A and  1306 B may be operated to change the color and saturation of the light beam together, or to change the saturation of the light beam independently. 
     Although the present invention has been described in detail, those skilled in the art should understand that various changes, substitutions and alterations may be made herein without departing from the spirit and scope of the invention in its broadest form. 
     Although the present invention and its advantages have been described in the foregoing detailed description and illustrated in the accompanying drawings, it will be understood by those skilled in the art that the invention is not limited to the embodiment(s) disclosed but is capable of numerous rearrangements, substitutions and modifications without departing from the spirit and scope of the invention as defined by the appended claims.