Patent Publication Number: US-2004040672-A1

Title: Device and method for shading a window

Description:
FIELD AND BACKGROUND OF THE INVENTION  
       [0001] The present invention relates to the field of window shades and, more particularly, to a window shading assembly that includes a shading element within a double pane unit that is usable in a building or motor vehicle.  
       [0002] It is common to shade windows from the entry of light and there are many reasons for doing so. In buildings, shaded windows provide privacy, glare control and protection from damage from UV radiation. In vehicles, shaded windows are used for the same purposes as well as to reduce the interior temperature of parked vehicles and to secure the safety of dignitaries.  
       [0003] There is almost no end to the array of decorative and functional devices and methods for shading windows, ranging from technologically enhanced glazing to the application of decorative window coverings.  
       [0004] Window shading known in the art includes the use of special substrates having light absorptive or reflective properties. Such glazing materials reduce the entry of heat and light producing radiation. One such glazing is disclosed by U.S. Pat. No. 6,387,514 which teaches a solar control substrate comprising a pyrolytically-formed coating layer containing oxides of tin and antimony which is highly reflective. Many others are known.  
       [0005] Special glazings may vary the amount of light that passes, as taught in U.S. Pat. No. 5,822,107 which shows an electrochromic glazing which permits the user, by applying an electrical current, to cause the glazing to pass from one degree of coloration to another.  
       [0006] Another common method of window shading is the application of a light absorptive or reflective film to an otherwise transparent or translucent window. Such films typically adhere to an existing pane and may contain many different optical properties, depending upon the application.  
       [0007] Less technically oriented shading is achieved by the application of window coverings such as drapery, curtains, window shades, venetian or slat blinds, and similar extra-window devices.  
       [0008] With respect to shading the windows of motor vehicles, the prior art is copious, as overheated parked vehicles is a serious problem to be solved. U.S. Pat. No. 3,046,048 discloses a magnetically secured windshield cover, which overlies and remains contiguous with the exterior of the automobile windshield. U.S. Pat. No. 2,843,421 shows an automobile windshield awning extending forward of the windshield to protect it against the elements. U.S. Pat. No. 3,184,264 shows a related type of windshield protector. U.S. Pat. No. 4,863,943 discloses an adjustable vehicle sunshade for fitting externally over the windshield and over the driver and passenger side windows. U.S. Pat. No. 4,784,215 discloses a thermal insulating shade for application over a vehicle window or windshield. U.S. Pat. No. 4,736,980 discloses another form of more permanent type of windshield shade. U.S. Pat. No. 4,560,245 discloses a vehicular windshield curtain for inhibiting heat transfer. U.S. Pat. No. 3,336,969 shows a vehicle windshield and rear window cover. U.S. Pat. No. 1,732,447 discloses a sun shield formed as a curtain for application inside an automobile window. U.S. Pat. No. 4,818,007 discloses a vehicle screen/shade. U.S. Pat. No. 4,790,591 shows a removable protective vehicle windshield screen. U.S. Pat. No. 4,671,558 discloses a rollable sunshield. U.S. Pat. Nos. 4,652,039 and 4,763,947 show other forms of windshield shade made out of paperboard which are collapsible into a smaller configuration for storage. U.S. Pat. No. 2,596,836 shows a glare shield for use inside an automobile window. U.S. Pat. No. 2,598,770 shows a flexible window screen. U.S. Pat. Nos. 2,614,630 and 2,979,129 show covers for application over the windshield. U.S. Pat. No. 2,065,242, shows another form of exterior windshield protector. U.S. Pat. No. 1,475,647, discloses an adjustable visor for vehicle windshields.  
       [0009] U.S. Pat. Nos. 4,332,414; 4,606,572; 4,861,090; 5,598,883 and 5,660,220 all teach fan like devices which unfold to provide shade and fold out of the way when not needed. U.S. Pat. No. 6,192,967 discloses a pivoting combination of fan sections. U.S. Pat. No. 6,402,222 teaches a fan type shade usable only for the side windows of automobiles.  
       [0010] Many of the listed shade devices are removable, and are simply folded up and put in the trunk or glove compartment. There are also many that are permanently installed and are stored out of the way when not in use. U.S. Pat. No. 6,086,133 shows a roll-up shade stowable in a horizontal surface such as the dashboard at the base of the window. U.S. Pat. No. 6,216,762 shows a shade which is stowed in its own base and extends by means of pivotal arms. U.S. Pat. No. 6,227,601 discloses an expanding and contracting slat shade stowed in the headliner of a vehicle.  
       [0011] As can be seen, there is almost no end to the devices that may be used to shade the windows of a motor vehicle. However, the recent innovations in shading devices and methods which include disposing the shading element within the window itself, such as between the two panes of a double glazed window, have not been applied to motor vehicles. Examples of such innovations include enclosing a pleated blind between the window panes, as disclosed in U.S. Pat. No. 4,913,213. Venetian blinds or slat blinds between panes of glass are disclosed in U.S. Pat. Nos. 4,687,040, 4,664,169 and 5,379,825. U.S. Pat. No. 6,397,917 teaches a more variable shade consisting of venetian blinds having an upper section which is adapted to redirect light entering the window upwardly against the ceiling of the room, and a lower section which is adapted to inhibit light from entering the room. The slats of the lower section can be pivoted independently of the slats of the upper section. All such devices are well known in the art.  
       [0012] Also well known in the art are control mechanisms for activating blinds within a double pane window. Such controls for lifting, lowering and tilting the blinds are preferably actuatable while maintaining the window seal and the insulating advantage of the double glazing. The prior art shows many different manually operated systems of cords, cables and gears as the control means, such as shown in U.S. Pat. No. 4,687,040. U.S. Pat. No. 6,070,638 teaches a window in which the blind can be raised, lowered and tilted while maintaining a seal between the window frame and the window panes.  
       [0013] Many of the double glazed windows containing venetian blinds have motorized control assemblies, as described in U.S. Pat. Nos. 4,723,586 and 4,979,552. U.S. Pat. No. 6,332,491 discloses an actuation assembly which relies for power upon permanent magnets and electromagnets.  
       [0014] Containing a shading device within a double pane window provides advantages, such as protecting the moving parts of the shade, ease of cleaning and avoiding external attachments hanging on the window.  
       [0015] However, none of the cited shading assemblies internal to double pane windows have been applied to motor vehicles for a number of reasons. First, a totally transparent window may not be achieved because elements of the system often cannot be totally removed from the field of view of the window without having an unnecessarily wide frame or housing around the panes. Thus, visibility is restricted. Second, the mounting of a venetian blind between the panes requires a space wide enough to accommodate the blind in the open position in which the slats lay horizontally, resulting in a very thick window unit, unusable for many applications including within motor vehicles. Third, because of the complexity of the shading member, such systems cannot be curved, such as to fit the contours of a motor vehicle. Fourth, because motor vehicles have irregularly shaped window openings, no light blocking member has been found that effectively shades the window.  
       [0016] There is thus a widely recognized need for, and it would be highly advantageous to have, a double pane window shading assembly that may be used in a motor vehicle and that does not suffer from the limitations and disabilities of the prior art.  
       SUMMARY OF THE INVENTION  
       [0017] Accordingly, it is an object of the present invention to provide a double pane shading assembly for use in a motor vehicle.  
       [0018] It is a further object of the present invention to provide a double pane shading assembly that is this and adaptable to a wide variety of applications.  
       [0019] According to one aspect of the present invention there is provided a shade assembly for shading a window opening comprising (a) two panes of transparent material disposed substantially parallel with a space therebetween forming a double pane having at least one open edge in communication with the space; (b) a light blocking member deployable within the space and retractable from within the space; and (c) a drive mechanism for deploying and retracting the light blocking member; the shade assembly being for deployment within the window opening.  
       [0020] According to another aspect of the present invention there is provided a shade assembly for shading a window opening comprising (a) two panes of transparent material disposed substantially parallel with a space therebetween forming a double pane sealed around its perimeter; (b) a light blocking fluid deployable within the space and retractable from within the space, the double pane having at least one opening in an edge thereof for the deployment and retraction of the fluid; (c) a reservoir for containing the fluid in fluid communication with the opening; and (d) a pump for deploying and retracting fluid; the shade assembly being for deployment within the window opening.  
       [0021] According to another aspect of the present invention there is provided a motor vehicle having installed therein a shade assembly for shading at least one window comprising (a) two panes of transparent material disposed substantially parallel with a space therebetween forming a double pane; and (b) a light blocking member deployable within the space and retractable from within space.  
       [0022] According to another aspect of the present invention there is provided a method of shading a window opening in a motor vehicle comprising (a) deploying within the window opening a shading assembly comprising two panes of transparent material disposed substantially parallel with a space therebetween forming a double pane; a light blocking member deployable within the space and retractable from within the space; and a mechanism for deploying and retracting the light blocking member; and (b) deploying the light blocking member within the space.  
       [0023] According to features in the described preferred embodiments the shade assembly further comprises a storage unit for stowing the light blocking member when the light blocking member is retracted.  
       [0024] According to features in the described preferred embodiments the double pane is for replacing a window unit within the window opening.  
       [0025] According to features in the described preferred embodiments the window opening is in a building.  
       [0026] According to features in the described preferred embodiments the window opening is in a motor vehicle.  
       [0027] According to features in the described preferred embodiments the light blocking member is substantially opaque.  
       [0028] According to features in the described preferred embodiments the light blocking member is partially translucent.  
       [0029] According to features in the described preferred embodiments the light blocking member is a film.  
       [0030] According to features in the described preferred embodiments the film is flexible.  
       [0031] According to features in the described preferred embodiments the film is a mesh.  
       [0032] According to features in the described preferred embodiments the film is formed of at least one material of the group consisting of a plastic, a rubber, a polymer, a polycarbonate and a metal.  
       [0033] According to features in the described preferred embodiments the storage unit comprises two guide tracks extending in parallel from said at least one open edge, said guide tracks being of sufficient length to contain said light blocking member when said light blocking member is in a retracted position, said guide tracks being oriented to guide the deployment and retraction of said film.  
       [0034] According to features in the described preferred embodiments the guide tracks are pivotable relative to the double pane.  
       [0035] According to features in the described preferred embodiments the storage unit comprises a roller for containing the film when the film is in a retracted position, the roller being oriented to guide the deployment and retraction of the film.  
       [0036] According to features in the described preferred embodiments the light blocking member is partially deployable to create a partially translucent state. According to features in the described preferred embodiments the shade assembly further comprises an air pump for aiding in deploying and retracting the fluid.  
       [0037] According to features in the described preferred embodiments the shade assembly is in a building.  
       [0038] According to features in the described preferred embodiments the shade assembly is in a motor vehicle.  
       [0039] According to features in the described preferred embodiments the fluid is mercury.  
       [0040] According to features in the described preferred embodiments the fluid is substantially opaque.  
       [0041] According to features in the described preferred embodiments the fluid is partially translucent.  
       [0042] According to features in the described preferred embodiments the pump is powered by a motor.  
       [0043] According to features in the described preferred embodiments the fluid is partially deployable to create a partially translucent state.  
       [0044] The present invention successfully addresses the shortcomings of the presently known configurations by providing a versatile double pane shading assembly that may be effectively used within a motor vehicle. 
     
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
     [0045] With specific reference now to the drawings in detail, it is stressed that the particulars shown are by way of example and for the purposes of illustrative discussion of the preferred embodiment of the present invention only, and are presented in the cause of providing what is believed to be the most useful and readily understood description of the principles and conceptual aspects of the invention. In this regard, no attempt is made to show structural details of the invention in more detail that is necessary for a fundamental understanding of the invention, the description taken with the drawings making apparent to those skilled in the art how the several forms of the invention may be embodied in practice.  
     [0046] In the drawings:  
     [0047]FIG. 1 a  is a diagrammatic illustration of a shade assembly constructed in accordance with a preferred embodiment of the present invention;  
     [0048]FIG. 1 b  is a diagrammatic illustration of the shade assembly of FIG. 1 a  in a different orientation;  
     [0049]FIGS. 2 a  and  2   b  are diagrammatic illustrations of the drive mechanism of the shade assembly of FIG. 1 a;    
     [0050]FIG. 3 is a diagrammatic illustration of the shade assembly of FIG. 1 a  installed in a building;  
     [0051]FIGS. 4 a ,  4   b  and  4   c  are diagrammatic illustrations of the shade assembly of FIG. 1 a  installed in a motor vehicle in different states of deployment;  
     [0052]FIGS. 5, 6,  7 ,  8  and  9  are diagrammatic illustrations of different installation alternatives of the shade assembly of FIG. 1 a;    
     [0053]FIG. 10 is a diagrammatic illustration of a shade assembly constructed in accordance with an alternative embodiment of the present invention;  
     [0054]FIG. 11 is a diagrammatic illustration of the shade assembly of FIG. 10 installed in a motor vehicle;  
     [0055]FIG. 12 is a diagrammatic illustration of a shade assembly constructed in accordance with a further alternative embodiment of the present invention;  
     [0056]FIG. 13 is a diagrammatic illustration of the shade assembly of FIG. 12 installed in a motor vehicle;  
     [0057]FIG. 14 is a diagrammatic illustration of a shade assembly constructed in accordance with a yet further alternative embodiment of the present invention;  
     [0058]FIG. 15 is a diagrammatic illustration of the shade assembly of FIG. 14 installed in a motor vehicle; and  
     [0059]FIG. 16 is a flow chart illustrating the method of the present invention. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
     [0060] The present invention is of a window shade assembly comprising a light blocking member deployable within the space between the two panes of a double pane window.  
     [0061] The principles and operation of a window shade assembly according to the present invention may be better understood with reference to the drawings and accompanying descriptions.  
     [0062] Before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not limited in this application to the details of construction and the arrangement of the components set forth in the following description or illustrated in the drawings. The invention is applicable to other embodiments or of being practiced or carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein is for the purpose of description and should not be regarded as limiting.  
     [0063] Reference is now made to FIG. 1 which shows a shade assembly in accordance with the teachings of the present invention, which is referred to hereinbelow as shade assembly  10 .  
     [0064] Shade assembly  10  is for shading a window opening in a building, such as a residence, office or other inhabited space, or in a motor vehicle. The window opening in which shade assembly  10  is deployed is hereinafter referred to as window opening  11 , irrespective of its nature or location. Accordingly, shade assembly  10  is installable in window opening  11  in place of an existing window unit or on the inside of an existing window unit or on the outside of an existing window unit.  
     [0065] According to a preferred embodiment, shade assembly  10  replaces an existing static window unit that does not open, such as is found in climate controlled buildings or motor vehicle windshields and rear windows. According to an alternative embodiment, shade assembly  10  also replaces a translating window unit that raises and lowers to allow air entry, in which case shade assembly  10  will also be capable of raising and lowering to allow the entry of air. Such an embodiment is described hereinafter.  
     [0066] Shade assembly  10  includes two panes of transparent material disposed substantially parallel with a uniform distance therebetween, forming a double pane, hereinafter referred to as pane  12 . Such double glazing is well known and commonly in use, particularly where thermal insulation is needed. The transparent material of pane  12  may be any glazing material desired according to the application. Although glass is a common and preferred glazing material, pane  12  may incorporate any glazing materials of any thickness desired, provided that it is appropriate to the specific application.  
     [0067] Pane  12  is formed with a space, hereinafter referred to as space  14 , between the two panes. The two panes of pane  12  are preferably joined around their perimeter. According to the preferred embodiment, it is not essential that the joint be sealed, rather it is necessary that the two panes simply be held in a stable manner in parallel at their edges, with space  14  substantially unobstructed. Such joining may be accomplished in many ways, including by fusing a spacer between the panes around the perimeter or by enclosing pane  12  within a perimeter frame which serves to retain the panes the desired distance apart.  
     [0068] Further according to the preferred embodiment, pane  12  has at least one edge open in communication with space  14 . This open edge is hereinafter referred to as opening  16 . Accordingly, the edges of the two panes at opening  16  will not be joined in any fashion nor contained within a frame. In the majority of applications, pane  12  will be shaped as a four sided polygon oriented substantially vertically with opening  16  as its lower edge.  
     [0069] Shade assembly  10  includes a light blocking member, which, according to the preferred embodiment, is a film, hereinafter referred to as film  18 . Film  18  is deployable within space  14  to prevent or impede the passage of light through pane  12  and is retractable to end the shading effect and restore full translucency to pane  12 .  
     [0070] Film  18  is preferably fabricated of plastic, rubber, polymer, polycarbonate or metal. The specific composition of film  18  is not a material element of the invention, provided that film  18  has the required degree of flexibility to deploy and retract as needed. It is understood that the various applications to which shade assembly  10  will be applied may require different degrees of flexibility. Therefore, the material of film  18  may vary according to the flexibility required by the specific embodiment.  
     [0071] Film  18  may have varying degrees of opacity and translucency, according to desire. In some applications, such as in a motor vehicle windshield, a totally opaque, ultra-violet blocking effect will be desired, whereas within an inhabited building, a certain degree of shading may be desirable. Accordingly, film  18  may be a mesh or a screen or any other appropriately translucent material.  
     [0072] Moreover, film  18  may have additional uses such as to provide one way visibility such that a person within the building or motor vehicle may see out while those outside may not see in; to add a decorative effect to the window by being colored or bearing a design; or to include a commercial element such as advertising. It is appreciated that film  18  is a versatile element subject to many forms and uses.  
     [0073] Shade assembly  10  also includes a storage unit for stowing film  18  when it is retracted, hereinafter referred to as storage unit  20 . According to the preferred embodiment, storage unit  20  comprises two guide tracks oriented in parallel and a connecting member, hereinafter referred to collectively as guide  21 , constituting a left guide  21   a , a right guide  21   b  and a connecting member  21   c . Left guide  21   a  and right guide  21   b  are positioned such that they extend from the sides of pane  12  perpendicularly from opening  16 . Connecting member  21   c  is attached therebetween at the distal ends of guides  21   a  and  21   b  in order to retain guides  21   a  and  21   b  in parallel orientation. Guide  21  is preferably formed of a rigid and durable material.  
     [0074] Left guide  21   a  and right guide  21   b  preferably have “U” shaped profiles oriented such that the interior of each “U” is facing one another, thus forming a continuous guide channel for the movement of film  18  such that film  18  may move unimpeded from space  14  into and out of guide  21 .  
     [0075] In some applications, storage unit  20  will form a continuous plane with pane  12 , such as when shade assembly  10  is installed in window opening  11  in a building with a straight vertical wall and guide  21  is positioned within the wall structure adjacent to window opening  11 . In other applications, such as in the windshield or rear window of a motor vehicle, storage unit  20  may be positioned along the hood, trunk lid or ceiling and therefore not in the same plane as pane  12 . For example, if storage unit  20  is positioned along the ceiling of a motor vehicle and pane  12  is for shading the windshield, pane  12  and shade assembly  10  will be fixed in an angular position relative to one another. In other applications, such as if storage unit  20  is positioned under the hood of a motor vehicle and pane  12  is for shading the windshield, pane  12  and storage unit  20  will require a variable angle therebetween in order to accommodate the raising and lowering of the hood so that guide  21  doesn&#39;t impede access to the engine when the hood is open. Accordingly, storage unit  20  will be pivotally attached to pane  12  at pivot point  19 , allowing storage unit  20  to pivot relative to pane  12  according to the requirements of its deployment.  
     [0076] Guide tracks  21   a  and  21   b  will preferably be of sufficient length to contain film  18  such that film  18  is completely out of space  14  or is not visible in pane  12  when film  18  is in a retracted position.  
     [0077] Reference is now made to FIGS. 2 a  and  2   b  which are diagrammatic illustrations of the drive mechanism of shade assembly  10 , hereinafter referred to as mechanism  22 . Shade assembly  10  comprises mechanism  22  for deploying and retracting film  18  from within space  14 . According to the preferred embodiment, the elements of mechanism  22  are located within the confines of guide  21 . FIG. 2 a  shows mechanism  22  removed from guide  21  in order to provide visibility to all of its elements. FIG. 2 b  shows mechanism  22  within guide  21 , with portions in phantom lines in order to show their position and orientation.  
     [0078] Mechanism  22  includes a motor, hereinafter referred to as motor  24 , which is preferably a DC electric motor suitable for motor vehicle current or may be an AC electric motor for installation within buildings. The voltage may vary depending upon location. Motor  24  will preferably include an integral speed reducing means such that the speed of rotation is appropriately slow. Many small motors for many different purposes are commercially available and the precise nature and size of motor  24  is not a material feature of the invention.  
     [0079] Motor  24  is preferably wired and switched such that its rotating shaft, hereinafter referred to as drive shaft  28 , rotates clockwise and counter clockwise. Motor  24  is preferably disposed within or adjacent to connecting member  21   c , oriented such that drive shaft  28  extends in both directions from motor  24  parallel to connecting member  21   c . Drive shaft  28  extends substantially to the ends of connecting member  21   c  and inserts within the “U” shaped channels of guides  21   a  and  21   b . Positioned on each end of drive shaft  28  are drive pulleys  30  which drive belts  32 . Positioned toward the upper ends of guides  21   a  and  21   b  and rotationally affixed thereto are corresponding pulleys  34 , which are respectively positioned coplanularly with drive pulleys  30  such that they may be driven by belts  32 . Accordingly, pulleys  30 , belts  32  and pulleys  34  move within the same plane and are preferably disposed within the “U” shaped channels of guides  21   a  and  21   b . It is appreciated that the function of pulleys  30  and  34  and belts  32  may be carried out by corresponding sprockets and chains, cables and other rotational elements, or other similar mechanisms.  
     [0080] In both FIGS. 2 a  and  2   b , film  18  is shown extending from opening  16  into guide  21  and terminating a short distance from connecting member  21   c . The lower terminal end of film  18  is preferably fitted with a rigid rod, hereinafter referred to as rod  36 , extending from within the channel of guide  21   a  to within the channel of guide  21   b  beyond the plane formed by pulleys  30  and  34  and belts  32 . Affixed to each of belts  32  is a holding device such as a ring, hereinafter referred to as rings  40 , for securing each end of rod  36  to a fixed position relative to belts  32  such that when belts  32  move, force is exerted against rod  36 . The nature of the holding device is not a material element and any holding device will suffice provided that it secures rod  36  to the designated location on belts  32 . Accordingly, the movement of belts  32  causes the movement of rod  36  and with it film  18 .  
     [0081] Motor  24  will preferably have a reversible switch such that it may be controlled by a user to rotate in either direction. Rotating in one direction will cause rings  40  on belt  32  to move toward opening  16 , thereby pulling rod  36  toward opening  16 , thus pushing film  18  into space  14 . Rotating in the opposite direction will cause rings  40  on belt  32  to move away from opening  16 , thereby pulling rod  36  away from opening  16 , thus pulling film  18  out of space  14 .  
     [0082] Mechanism  22  will further comprise a pair of micro switches  42  affixed to guide  21  in order to stop the movement of motor  24  when tripped. One micro switch  42  is positioned where it will be tripped by rod  36  when rod  36  is at its most extended position, thus stopping the retraction movement of film  18  when it substantially reaches the distal end of guide  21 . The other micro switch  42  is positioned where it will be tripped by rod  36  when rod  36  is at its most proximal location relative to opening  16 , thus stopping the deployment movement of film  18  when it substantially reaches the distal end of space  14 .  
     [0083] In addition, mechanism  22  may preferably be connected to any alarm system that may be installed within a building or motor vehicle, such that tampering with shade assembly  10  will actuate the alarm, or tampering with the window, building or motor vehicle itself will activate shade assembly  10  causing it to shade or unshade the window as may be desired. When shade assembly  10  is installed in a motor vehicle, mechanism  22  may preferably be actuatable in conjunction with the operable elements of the motor vehicle in order to provide safety or security, for example, by shading the windows only when the transmission is in “neutral” or “park”. All such actuation methods or uses are contemplated as being within the scope of the present invention.  
     [0084] According to the above described configuration, mechanism  22  will preferably push film  18  into space  14  in order to deploy it and pull film  18  out of space  14  in order to retract it. It is understood that other deployment mechanisms may be employed which pull film  18  into space  14  for deployment and push film  18  out of space  14  for retraction, or deploy and retract it in different manners. Many different deployment mechanisms are known in the art for deploying different shading elements between the panes of double glazed windows. For example, U.S. Pat. No. 6,086,133 shows a mechanism that includes parallel threaded rods that rotate causing holders fixed on nuts threaded on the rods to move with respect to the rods according to the direction of rotation. Any of such mechanisms that may be effective in deploying and retracting film  18  may be applied to shade assembly  10  without detracting from the novelty of the present invention. The described mechanism  22  is a simple and effective drive mechanism and it is appreciated that it is not the only drive mechanism that may be applied.  
     [0085] Reference is now made to FIG. 3 which is a diagrammatic illustration of shade assembly  10  installed in a wall of a building  44 . Shown is pane  12  with film  18  approximately 80% deployed therein. Storage unit  20  is shown in phantom lines hidden within the wall structure beneath window  11 .  
     [0086] Reference is now made to FIGS. 4 a ,  4   b  and  4   c  which are diagrammatic illustrations of shade assembly  10  installed in the windshield  45  of a motor vehicle  46  in different states of deployment. Shown in all three figures is pane  12  in identity with windshield  45 , film  18  in various stages of deployment, and storage unit  20  in phantom lines under the hood of motor vehicle  46 . FIG. 4 a  shows film  18  fully retracted. FIG. 4 b  shows film  18  partially deployed. FIG. 4 c  shows film  18  fully deployed. It is observed that storage unit  20  is stowed adjacent to the underside of the hood of motor vehicle  46  and is therefore not in the same plane as pane  12 . As described hereinbefore, it is necessary that storage unit  20  be capable of pivoting relative to pane  12  as the hood of motor vehicle  46  is opened and closed so that storage unit  20  does not impede access to the engine of motor vehicle  46 . It is understood that in such embodiments in which pane  12  replaces an exterior window of a motor vehicle, pane  12  must meet all applicable safety and optical standards.  
     [0087] Reference is now made to FIGS. 5, 6 and  7  which are diagrammatic illustrations of different installation alternatives of shade assembly  10 . Shown in all three figures is pane  12  installed to shade rear window  47 , with film  18  in partial deployment, and with storage unit  20  in phantom lines stored under the trunk lid of motor vehicle  46 . FIGS. 5, 6 and  7  respectively show shade assembly  10  installed with pane  12  on the inside of an existing window unit, on the outside of an existing window unit and in place of an existing window unit. It is understood that the three different dispositions shown are applicable to any window opening  11  in which shade assembly  10  is installed.  
     [0088]FIG. 5 shows pane  12  disposed outside of and adjacent to rear window  47 . In such a disposition, pane  12  will be strongly attached to either rear window  47  or to the body of motor vehicle  46  surrounding rear window  47  so that it does not detach therefrom as a result of driving agitation or wind forces. In such a configuration, the body of motor vehicle  46  must be modified to provide for an opening sufficiently large to allow pane  12  to pass therethrough in order to lie adjacent to the outside of rear window  47 .  
     [0089]FIG. 6 shows pane  12  in identity with rear window  47 . In such a disposition, pane  12  serves as rear window  47 .  
     [0090]FIG. 7 shows pane  12  disposed inside of and adjacent to rear window  47 .  
     [0091] In all three dispositions shown, it is necessary that storage unit  20  be capable of pivoting relative to pane  12  as the trunk lid of motor vehicle  46  is opened and closed so that storage unit  20  does not impede access to the trunk of motor vehicle  46 .  
     [0092] Reference is now made to FIGS. 8 and 9 which show further installation alternatives of shade assembly  10  in a motor vehicle. Both figures show shade assembly  10  disposed on the ceiling  48  of motor vehicle  46 , with phantom lines showing the location of storage unit  20  and with film  18  partially deployed. FIG. 8 shows pane  12  in identity with windshield  45  and FIG. 9 shows pane  12  in identity with rear window  47 . In both figures it is noted that storage unit  20  is in an angular orientation with respect to pane  12 .  
     [0093] Reference is now made to FIG. 10 which shows an alternative embodiment of shade assembly  10  which is particularly applicable for installations in which pane  12  replaces a window unit that opens and closes by raising and lowering into a window opening, such as the side windows of motor vehicles. The illustrated alternative embodiment is similar to the preferred embodiment illustrated in FIGS. 1 and 2 and employs the majority of the elements of storage unit  20  and drive mechanism  22 . Therefore, where the alternative embodiment shown in FIG. 10 includes the same parts as shown in FIGS. 1 and 2, the same numbers are used in FIG. 10.  
     [0094] According to the alternative embodiment, shade assembly  10  may preferably include an identical pane  12  and mechanism  22  as is included in the preferred embodiment. One difference will be that pane  12  is not attached to storage unit  20 , as provided in the preferred embodiment. Rather, pane  12  will not be pivotally or otherwise connected to guide  21 , but will fit within guide  21 . Guide  21  will be configured sufficiently wide between the legs of its “U” profile such that pane  12  may move up and down the channel formed by the opposite guides  21   a  and  21   b . The presence of pane  12  within guide  21  need not interrupt nor disturb the operation of mechanism  22 .  
     [0095] Accordingly, both film  18  and pane  12  will move up and down within guide  21 , with film  18  oriented such that it slides into and out of space  14  as needed by the relative positions of pane  12  and film  18 . For example, when pane  12  is in the up or closed position, film  18  may be in its deployed state within space  14  or in its retracted state stowed within guide  21 . When pane  12  is in its down or open state, film  18  must be in its retracted state within guide  21 , but pane  12  will have descended also within guide  21  and will fit over film  18  such that film  18  is within space  14  even while retracted.  
     [0096] Both pane  12  and film  18  require drive mechanisms for their respective movements. Pane  12 , which replaces the window unit, will preferably be operable by the existing window drive mechanism which normally operates the window unit. Film  18  may be operable by mechanism  22 , as shown in the preferred embodiment. It is appreciated that the respective drive mechanisms may be combined in various aspects or one or the other of the two drive mechanisms may be modified to operate both pane  12  and film  18 . Such drive mechanisms that operate a plurality of parallel moving members are known in the art.  
     [0097] The electrical system of mechanism  22  must be modified in order to provide for this difference in operation from the preferred embodiment. For example, film  18  must be prevented from deploying when pane  12  is in the down or open position. In addition, when pane  12  is in the up or closed position and film  18  is deployed therein, moving pane  12  down must also cause film  18  to retract. Both of such requirements may be met by simple switching arrangements that are well known in the art and commonly in use.  
     [0098] Reference is made to FIG. 11 which shows the alternative embodiment of FIG. 10 installed in a side window of motor vehicle  46 . Shown is pane  12  partially raised with film  18  deployed therein. Storage unit  20  is shown in phantom lines within the door of motor vehicle  46 .  
     [0099] Reference is now made to FIG. 12 which shows an alternative embodiment of shade assembly  10  which is particularly applicable for installations in which there is not sufficient space to accommodate storage unit  20  in the form of guide  21 , which extends from pane  12 , effectively doubling its size. Such an embodiment may be installed below windshields or rear windows or within doors of motor vehicles to shade the side windows.  
     [0100] According to the alternative embodiment, storage unit  20  comprises a roller, hereinafter referred to as roller  50 , for containing film  18  in its retracted state rather than the extending guide  21  of the preferred embodiment. However, the illustrated alternative embodiment remains similar to the preferred embodiment illustrated in FIGS. 1 and 2 in many respects and employs the majority of the elements of drive mechanism  22 . Therefore, where the alternative embodiment shown in FIG. 12 includes the same parts as shown in FIGS. 1 and 2, the same numbers are used in FIG. 12.  
     [0101] As shown, roller  50  will preferably be disposed below motor  24  and drive shaft  28 , oriented with its axis parallel to drive shaft  28  and to opening  16  of pane  12 . Roller  50  will be so positioned that film  18  will be deployed from roller  50  into space  14  and retracted from space  14  on to roller  50  without impediment. Accordingly, roller  50  will preferably be located close to and aligned with opening  16 .  
     [0102] Roller  50  will rotate about an axial shaft  51  which will preferably be supported on both ends by guide  21  (not shown) which are positioned adjacent to the sides of pane  12 , rather than extending from the sides of pane  12  as is shown in Figure. Accordingly, the same mechanism  22  of the preferred embodiment may be employed in the alternative embodiment with only slight modification. According to this alternative embodiment, motor  24  and drive shaft  28  with pulleys  30  thereon are the same and remain supported by guide  21  (not shown). The remainder of mechanism  22 , specifically pulleys  34  and belts  32 , will similarly be disposed within guide  21  which is positioned adjacent to the sides of pane  12 . Therefore, in order to accommodate this new position of mechanism  22 , rod  36  is attached at the top end of film  18  rather than at the bottom end of film  18 . In order for this configuration to be effective, another modification of the preferred embodiment is needed. Rod  36  must pass into space  14  and extend beyond the sides of pane  12  in order to engage rings  40  of mechanism  22 , which is now positioned adjacent to the sides of pane  12 . Therefore, according to the alternative embodiment, the sides of pane  12  are provided with longitudinal slots  52  such that rod  36  may extend therethrough order to move with respect to pane  12  as propelled by rings  40 . It is appreciated that according to the alternative embodiment, rod  36  pulls film  18  into space  14  upon deployment and pushes film  18  out of space  14  upon retraction.  
     [0103] In a variation of the alternative embodiment, an electromagnet may preferably be disposed in the distal end of space  14  and rod  36  may be formed of a ferrous metal in order to create a magnetic force that will assist in the deployment of film  18 . In a further variation of the alternative embodiment, roller  50  may preferably be provided with a coiled spring which is tensioned by the rotation of roller  50  in the direction of the deployment of film  18 , thus storing energy which assists in the retraction of film  18 . Such springs are commonly in use in window shades and other applications.  
     [0104] Reference is now made to FIG. 13 which shows the alternative embodiment of FIG. 12 installed in a rear window of motor vehicle  46 . Shown is pane  12  with film  18  partially deployed therein. Roller  50  is shown in phantom lines below pane  12 .  
     [0105] Reference is now made to FIG. 14 which shows yet a further alternative embodiment of shade assembly  10  which is particularly applicable for installations in which the window unit is irregularly shaped or curved. According to the alternative embodiment, shade assembly  10  comprises pane  12 , similar in configuration and materials to pane  12  of the preferred embodiment, but sealed around its perimeter such that it retains fluid within space  14  without leakage.  
     [0106] According to the alternative embodiment, shade assembly  10  comprises a light blocking fluid, hereinafter referred to as fluid  60 , that is deployable within space  14  in order to block the passage of light through pane  12 . Fluid  60  has certain required properties that enable it to function effectively in the described application. First, it must have a certain degree of opacity/translucency according to desire. In some applications, such as in a motor vehicle windshield, a totally opaque, ultra-violet blocking effect will be desired, whereas within an inhabited building, a certain degree of shading may be desirable. Accordingly, fluid  60  may be totally impervious to light passage or it may be slightly “smoky”, “milky” or colored in order to provide the desired degree of translucency and/or visibility.  
     [0107] Second, to be effective as fluid  60 , a fluid must not adhere to the inside surfaces of pane  12  after retraction. Therefore, fluid  60  must have low adhesion characteristics. Adhesion is herein defined to mean the propensity of a fluid to adhere to a body with which it comes into contact. Fluids are often differentiated by their ratio of adhesive force/cohesive force. For example, highly volatile fluids like alcohols typically have high adhesive force and low cohesive force. Thus, a quantity of such a fluid coming into contact with an object will not stick together but will adhere and spread widely on the surface of the object Conversely, a fluid like mercury has extremely high cohesive force and low adhesive force. Therefore, a quantity of mercury that comes into contact with an object will tend to stick together rather than disperse or adhere to the object. Further measures that may be taken to avoid residual deposits of fluid  60  within space  14  include coating the inside surface of space  14  with a substance that is inherently non adhesive, such as TEFLON™, or coating the surface of space  14  with a charged substance and selecting an ionized fluid  60  that will be repelled by the coating, or fabricating pane  12  of water repellant glass and selecting a water-based fluid  60 .  
     [0108] Third, fluid  60  must be capable of withstanding the high temperatures produced by sunlight without evaporating.  
     [0109] Finally, fluid  60  must have an appropriate viscosity such that it may be deployed by pumping into space  14  and retracted by vacuum or by air pressure from space  14 .  
     [0110] Accordingly, an effective fluid  60  to serve as a light blocking fluid is mercury. Additional fluids that may be used include oil based, water based or antifreeze based fluids in conjunction with appropriate repellent coatings on the interior surfaces of space  14 . It is appreciated that the specific fluid serving as fluid  60  is not a material element of the invention and any fluid that exhibits the required properties and that may be deployed into space  14  and retracted therefrom without a residue may be used.  
     [0111] According to the alternative embodiment, shade assembly  10  further comprises a reservoir, hereinafter referred to as reservoir  62 , for containing fluid  60 . Reservoir  62  may be of any shape required in order to fit into the space provided for it and may be made of any durable material impervious to disintegration or dissolution as a result of contact with fluid  60 . Reservoir  62  will be in fluid communication with space  14  via fluid tube  66  which is in fluid communication with space  14  via at least one opening in pane  12 , hereinafter referred to as opening  64 . Opening  64  is preferably located on a bottom edge of pane  12  in order to allow gravity to aid in the retraction of fluid  60  from space  14 .  
     [0112] According to the alternative embodiment, shade assembly  10  further comprises a fluid pump, hereinafter referred to as pump  68 , which is interposed within fluid tube  66  for deploying fluid  60  by pumping fluid  60  from reservoir  62  into space  14  and for retracting fluid  60  by pumping fluid  60  from space  14  into reservoir  62 . Many suitable manual and powered fluid pumps are commercially available for two-way transfer of fluids from one container to another. The specific pump selected as pump  68  is not a material element of the present invention.  
     [0113] Pump  68  is preferably powered by an electric motor (not shown) which is preferably a DC electric motor suitable for motor vehicle current or may be an AC electric motor for installation within buildings. The precise nature and size of the electric motor is not a material feature of the invention provided that it is suitable for activating pump  68 .  
     [0114] According to the alternative embodiment, shade assembly  10  further comprises an air pump, hereinafter referred to as pump  70 , which is in fluid communication with space  14  via an opening  72  in pane  12 . Pump  70  is useful in the retraction of fluid  60  by causing positive pressure within space  14  to exert force on fluid  60  and assist the pumping action of pump  68 . Pump  70  is also preferably reversible such that it is operable to remove air from within space  14  to aid in the deployment of fluid  60 . No specific air pump is designated as pump  70  as many small capacity pumps are commercially available that will serve the function of pump  70 .  
     [0115] Opening  72  is preferably located on a top edge of pane  12  so that it will not be blocked as fluid  60  enters space  14 . Moreover, in instances in which pump  68  retracts fluid  60  from space  14  without the aid of pump  70 , opening  72  so located will serve as a pressure equalizer so that air may enter to replace the retracted fluid  60 .  
     [0116] It is appreciated that a motor vehicle may have multiple window units of shade assembly  10  to be shaded according to the above described alternative embodiment. Accordingly, it is within the scope of the present invention to equip motor vehicle  46  with a system which includes a common reservoir  62 , a common fluid pump  68  and a common air pump  70  for deploying and retracting fluid  60  within each window unit to be shaded. According to such a system, fluid tube  66  will necessarily comprise a network of fluid tubes  66  leading from the common pump  68  to each window, and air pump  70  will similarly have a network of air tubes  74  leading to each separate window unit. It is understood that each network of fluid tubes  66  and air tubes  74  will necessarily require careful and intricate valving to assure the passage of fluid and air to the desired window unit.  
     [0117] Reference is now made to FIG. 15 which shows the alternative embodiment of FIG. 14 installed in a rear window of motor vehicle  46 . Shown is pane  12  with fluid  60  partially deployed therein. Reservoir  62 , pump  68 , fluid tube  66 , air pump  70  and air tube  74  are shown in phantom lines below pane  12 .  
     [0118] Reference is now made to FIG. 16 which shows a flow chart illustrating a method of shading a window opening in a motor vehicle, hereinafter referred to as method  80 . Method  80  comprises the following steps:  
     [0119] Step  1 . Deploying within a window opening in a motor vehicle a shading assembly comprising a double pane formed of two panes of transparent material disposed substantially parallel with a space therebetween, and a light blocking member deployable within the space and retractable from within the space.  
     [0120] Step  2 . Deploying the light blocking member within the space of the double pane.  
     [0121] It is understood that the various embodiments of shade assembly  10  hereinbefore described are appropriate for use in method  80 . It is also understood that any variations of any of the embodiments of shade assembly  10  will similarly be appropriate for use in method  80  and are contemplated as being within the scope of the present invention so long as they include the elements set forth in the above two steps constituting method  80   
     [0122] It is appreciated that certain features of the invention, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the invention which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable subcombination.  
     [0123] It will be appreciated by persons skilled in the art that the present invention is not limited to what has been particularly shown and described hereinabove. Rather, the scope of the present invention is defined by the appended claims and includes both combinations and subcombinations of the various features described hereinabove as well as variations and modifications thereof which would occur to persons skilled in the art upon reading the foregoing description. Accordingly, it is intended to embrace all such alternatives, modifications and variations that fall within the spirit and broad scope of the appended claims.