Abstract:
A light source device is provided for separating light into several light components with a plurality of colors or hues which includes a source of white light and at least one dichroic filter carried on an envelope of the light source device. The filter selects a particular wavelength band from a visible light spectrum and transmits only light from the selected wavelength band therethrough. The filter includes a mirror for reflecting light having a wavelength band other than the selected wavelength band whereby all transmitted light exits the device in different combinations of colors or hues. Several filters and mirrors may be arranged adjacent to each other with respect to the light source and the apparatus therefore transmits ideally 100% of the light from the light source and no additional means are required for dissipating or absorbing the non-selected wavelength bands since all bands or rays are included in the multi-colored emission.

Description:
Priority claimed based on Ser. No. 60-100,798 filed Sep. 18, 1998 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to the field of light source apparatus for separating white light into light components of a plurality of colors, and more particularly to a novel lamp device having multi-colored radiant output with high efficiency for use in decorating or display applications. 
     2. Brief Description of the Prior Art 
     In the past, conventional colored floodlights, colored spotlights or colored lights have been employed for use in architectural, landscaping and various display lighting. In such prior uses, conventional colored floodlights or the like emitted a single hue and were used in multiple lamps in order to produce alternate color lighting effects. Since the light source within a single lamp emits multiple hues, pairs of filters or mirrors are sometimes employed so as to permit only a selected hue to be emitted. The unselected or undesired hue is then dissipated or absorbed within the lamp. Some lamps use light-absorbing filters to remove the unwanted wavelengths and to dissipate the energy as heat. Others use dichroic filters in the form of thin film to reflect the undesired wavelengths to a surface within the lamp where the undesired wavelengths are dissipated as heat. Efficiency of such prior lamp construction is very low, especially when saturated hues, such as red, green or blue are transmitted. 
     Such a conventional light source is disclosed in U.S. Pat. No. 5,096,280 which describes a light source apparatus for separating a white light into light components of a plurality of colors. However, only a single color is eventually emitted with undesired or unselected colors or hues being blocked by dichroic filters. Therefore, such a prior light source apparatus is inefficient and usage is very limited. The lamp disclosed in U.S. Pat. No. 4,839,553 pertains to a light source that divides color rays out and unwanted or non-selected rays are absorbed into a housing and are not used. 
     Therefore, a long-standing need has existed to provide a multi-colored light source for decoration or display applications that is more efficient than that described by the prior art and which includes a single multi-colored lamp source which not only emits a plurality of colors or hues but selectively emits the colors or hues in appropriate directions by employing dichroic coatings or filters and reflectors to direct and redirect colored rays to desired display locations. 
     SUMMARY OF THE INVENTION 
     Accordingly, the above problems and difficulties are avoided by the present invention which provides a novel light source device for separating a light into several light components or rays composed of a plurality of colors or hues and which includes a single source of high efficiency light and at least one dichroic filter carried on an envelope of the light source device. The filter selects a particular wavelength band from the viable high efficiency light and transmits only light from the selected wavelength band therethrough. The filter, including a reflector or mirror, reflects or redirects the wavelength band other than the selected wavelength band so that all rays of the transmitted wavelength band exit the lamp. Several filters and/or mirrors may be arranged adjacent to each other and with respect to the light source and the apparatus therefore transmits ideally 100% of the light from the single light source and no additional means are required for dissipating or absorbing the undesired wavelength bands or rays. 
     Therefore, it is among the primary objects of the present invention to provide a lamp that employs a single light source and at least one dichroic filter and reflector arrangement to separate selected wavelengths or color groups of the visible spectrum and that distributes the selection in a desired direction to produce multi-colored emission. 
     Another object of the present invention is to provide a multi-colored lamp device wherein the emitted light can range from high color saturation to low color saturation and wherein many lamp arrangements are employed for floodlight purposes, spotlights or other omnidirectional emission lamps. 
     Still a further object of the present invention is to provide a lamp device having multi-colored radiant output wherein the visible wavelengths that are emitted from a single light source are transmitted through the lamp envelope through dichroic filters and reflectors to produce a desired effect and provide high efficiency without utilizing light ray dissipating or absorption means. 
     Another object resides in allowing higher wattages to be placed in smaller lamp envelopes than conventional colored lighting systems can be housed. 
     Further, an object resides in the ability of the inventive concept to separate colors by wavelengths and to redirect selective wavelengths so that efficiency is increased by utilizing most of the visible spectrum from a single source. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The features of the present invention which are believed to be novel are set forth with particularity in the appended claims. The present invention, both as to its organization and manner of operation, together with further objects and advantages thereof, may best be understood with reference to the following description, taken in connection with the accompanying drawings in which: 
     FIG. 1 is a perspective view of a lamp device having multi-colored radiant output from a single light source in accordance with the present invention without heat dissipating or heat absorption means; 
     FIG. 2 is a transverse cross-sectional view of the lamp device shown in FIG. 1; 
     FIG. 3 is a side elevational view, partially broken away, to illustrate the interior of the lamp device shown in FIGS. 1 and 2; 
     FIG. 4 is a diagrammatic view of an alternate lamp device having multi-colored radiant output in accordance with the present invention; 
     FIG. 5 is a diagrammatic view of a lamp device incorporating another version of the present invention; 
     FIG. 6 is still another version of the lamp device incorporating the present invention; 
     FIGS. 7 and 8 illustrate an alternate version of lamp device having multi-colored radiant output; and 
     FIG. 9 is a lamp device incorporating a protective cover incorporating different dichroic filters. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring to FIGS. 1 and 2, a lamp incorporating the present invention is illustrated in the general direction of arrow  10  which includes an envelope  11  which encloses a vacuum area having a single filament  16  as a light source that terminates with an electrical screwtype socket  12 . The envelope  11  has a clear portion  13  and a layer or coating of dichroic filter/mirror material  14  which for illustrative purposes can be stated as being a yellow dichroic filter and a reflective mirror combination. In this embodiment, light emitting from the filament  16  is a white light and the yellow component Y of the color spectrum will pass through the yellow dichroic filter  14  while the blue color component B of the spectrum will be reflected back through the clear portion of the envelope or bulb  13 . In this example, a yellow light is emitted from half of the lamp and the other half emits a bluish-white light. Only one color of dichroic filter is employed for emitting two colors and none of the colors in the spectrum are blocked so that there is an absence of heat energy accumulation. 
     In FIG. 2, the bulb  10  has been modified with a second color of dichroic filter such as blue, which is indicated by numeral  15 . In this example, the white light emanating from the filament  16  is radiated against the yellow dichroic filter  14  and the blue dichroic filter  15 . The blue component or portion B of the white light spectrum will pass through the filter  15 , as indicated by numeral  17 , while the yellow portion &amp; of the white light emission will pass through the yellow dichroic filter  14  in the direction of arrow  18 . The blue portion B of the white light striking the yellow dichroic filter  14  will be mirrored or reflected back along arrow  19  to exit via filter  15 . The yellow portion Y of the white light which strikes the blue filer  15  will be redirected or reflected back through the yellow filter  14  in the direction of arrow  20 . Thus, in both FIGS. 1 and 2 it can be seen that the efficiency of the lamp  10  is greatly increased by the use of dichroic filters which will pass a portion of the white light with the remainder portion of the white light being reflected back through either a second filter or an unfiltered portion of the lamp envelope. None of the light rays are prevented from exiting the envelope. 
     Referring to FIG. 3, it can be seen that the single filament.  16  emits a white light which radiates against the entire inside of the envelope  11 . However, with the presence of filters strategically or critically located on the envelope, certain colors of the spectrum will be passed directly through the envelope and others reflected for emission through another portion of the envelope. As explained with respect to FIG. 2, white light striking the blue filter  15  will permit the blue component  17  to pass through while the yellow component Y will be reflected back and passed through the yellow filter  14 , as indicated by arrow  20 . Likewise, the yellow component Y of the white light radiation will strike the yellow filter  14  and pass through, as indicated by arrow  18 , while the blue component B will be reflected or mirrored back through the blue filter  15 , as indicated by arrow  19 . If desired, a transparent globe or envelope may be placed around the filament  16 , as is indicated by numeral  21  so as to create an internal light source or lamp per se. Such construction is used in conventional lighting techniques without colored filters and, therefore, it is within the concept of the present invention to use colored dichroic filters on the globe  21  in the same fashion as previously described with respect to embodiments  1  through  3  inclusive. 
     Referring now in detail to FIG. 4, another version of the lamp device of the present invention is illustrated in the general direction of arrow  25  which includes a reflector envelope  26  that is of a conical configuration terminating at its apex in an electrical screw-type connector  27 . A single light source  28  is included which may or may not be surrounded by an envelope  30 . Immediately ahead of the filament and the envelope  30 , a dichroic filter/mirror  31  is included which has alternate and different color filters across its length. If desired, a diffuser  32  may be employed. The opposite end of the reflector envelope  26  includes a lens or lenses, identified by numeral  33 . Therefore, as white light is emitted and radiated from the single filament  28 , it can pass through the pattern of dichroic filters  31  and the respective colors of the spectrum will pass through certain portions of the overall filter. These portions are then combined and passed through thelens  33 , as shown by the multiple arrows. Each arrow represents a beam of different colored light depending on the arrangement of the dichroic filters in the pattern  31 . Arrow  29  is a light ray of a color that cannot pass through a portion of the filter but is redirected or reflected back to the reflection surface of the envelope  26  for redirection back to an acceptable portion of the filter. 
     It is also to be understood that similar to the embodiment shown in FIG. 3, the envelope  30  may include dichroic filter layers of different colors and that the pattern of the layers depends on the ultimate color radiation desired. It is also to be understood that the filter  31  may be linear or may be circular with a random placement of dichroic filters spaced apart from one another. A typical pattern for a linear arrangement would commence at one end with magenta followed by green, white, yellow and blue. 
     Referring now to FIG. 5, another version of the lamp is indicated in the general direction of arrow  35  and this embodiment is similar to the embodiment shown in FIG. 4 with the exception that the lens is not required. In this embodiment, white light is radiated through the first envelope  36  which includes a blue dichroic filter  37  on one half of the envelope  36  and a yellow dichroic filter/mirror  38  on the other half of the envelope  36 . The filter may be solid, fully occupying the interior of envelope  36  or the filter may be a coating or layer on the inside surface of the envelope  36 . In either event, the white light is radiated to the respective filters and the respective blue and yellow components will pass through the filters and be reflected against the inside surface of an envelope or bulb  40  where the beams are reflected into a parallel relationship for emitting through a clear window  41  or opening. Again, the principle is the same as previously described wherein the efficiency of the lamp device is greatly improved since a single lamp can handle and distribute a plurality of colors simultaneously. Little visable energy is lost and there is no need to provide for heat elimination or dissipation of any unused color or radiation. 
     Referring now in detail to FIG. 6, another version of the invention is illustrated in the direction of arrow  45  wherein a filament  46  emits white light which is then reflected against the surface of the lamp envelope  47  and subsequently redirected to a lens or window  48 . It is to be particularly noted that the white light is indicated by numeral  46  as an example and that when reflected, will still be white light until the light reaches a plurality of different colored dichroic filters/mirrors. For example, green filters may be indicated by numerals  51  and  52  while magenta filters are indicated by numerals  53  and  54 . 
     FIGS. 7 and 8 illustrate another version of the invention where the dichroic filters/mirrors are of a solid nature residing within the envelope  55  so that when white light is radiated from filament  46 , the rays will immediately pass through solid dichroic material. As an example, FIG. 7 is a transverse cross-section which shows the solid arrangement of dichroic filters wherein one side may be of a yellow filter, as indicated by numeral  57 , while number  58  illustrates a blue dichroic filter. White light from the source  46  proceeds through the filters with blue and yellow rays passing through blue and yellow filters respectively and their counterpart of blue and yellow rays which do not pass through the filters are returned to the back inside surface of the envelope  55  for reflection through the appropriate filter. In this fashion, efficiency is increased. 
     Referring now in detail to FIG. 9, another version of the invention is illustrated wherein a screw-type lamp connector  60  carries a filament  61  within a quartz halogen lamp  62 . A protective cover  63  is placed over the quartz halogen generator for protecting the user from the quartz halogen explosion. The present invention includes the placing of a blue dichroic filter/mirror  64  on the protective cover  63  and a yellow dichroic filter/mirror  65  on another side or half of the protective cover. Therefore, the principle of radiation, as previously explained with respect to the yellow and blue components of the light are used. 
     In view of the foregoing, it can be seen that the present invention provides a multi-colored light or lamp device for decorating or display applications that is more efficient than those employed in the prior art. The inventive lamp concept includes a light source with dichroic filters that separate selected wavelengths or color groups of the visible light spectrum and distribute these in a desired direction or directions to produce multi-colored emission. The emitted light can range from high color saturation to low color saturation. Many lamp arrangements are available from floodlights, spotlights or the like to omnidirectional emission lamps. Most of the visible wavelengths that are emitted from the light source are transmitted through the lamp to produce the desired effect and provide high efficiency. 
     While particular embodiments of the present invention have been shown and described, it will be obvious to those skilled in the art that changes and modifications may be made without departing from this invention in its broader aspects and, therefore, the aim in the appended claims is to cover all such changes and modifications as fall within the true spirit and scope of this invention.