Abstract:
An improved compact searchlight utilizing the merging of multiple single beams to a concentrated light. This provides or light beam that is nearly constant illumination intensity across the beam of light. This reduces or eliminates bight and dim areas that are created from previous light systems that use desecrate lighting elements. The lighting elements includes an a power supply a light source and a lens projection system, wherein the lens projection system including a collecting lens, a negative lens, and a collimating lens such that the illuminance of an area illuminated by a beam and searchlight is projected by the improved light is homogeneous throughout the whole of the illuminated area.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application is a continuation of application Ser. No. 12/369,834, filed on Feb. 12, 2009 now U.S. Pat. No. 8,696,174 that issued on Apr. 15, 2014 which claims the benefit of Provisional Application Ser. No. 61/086,078 filed Aug. 4, 2008 the entire contents of which is hereby expressly incorporated by reference herein. 
    
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not Applicable 
     THE NAMES OF THE PARTIES TO A JOINT RESEARCH AGREEMENT 
     Not Applicable 
     INCORPORATION-BY-REFERENCE OF MATERIAL SUBMITTED ON A COMPACT DISC 
     Not Applicable 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to a light source, and more particularly to a search light that uses multiple light sources to create a single concentrated beam of light as a menorah configuration of light sources. 
     2. Description of Related Art including information disclosed under 37 CFR 1.97 and 1.98 
     Collimators are well known in the optical arts, and typically include a plurality of lens or reflectors that act upon light to emit nearly parallel rays. Such collimators include searchlights, headlamps and light projectors. A typical example of a light projector designed to emit a collimated beam can be found in U.S. Pat. No. 5,918,968, issued to Choi, which provides a parabolic reflector for converting light emitted from a lamp to parallel rays, a biconvex lens for collimating both direct and reflected light from the light source, a combination lens having a first lens and a second lens for focusing the collimated light from the biconvex lens to a focal point, and an image lens located beyond the focal point for converting the light focused at the focal point into a parallel beam. 
     U.S. Pat. No. 6,827,475, issued to Vetorino et al., combines a plurality of lens and reflectors to collimate light that includes a conical reflector disposed about the base of a light emitting diode (LED) and a lens specially designed to focus the collected light into a nearly collimated beam. The lens have opposite, substantially elliptical surfaces that collect and collimate the rapidly diverging light from the LED and the reflector. Vetorino et al., however, do not provide for the compression of the collimated beam. 
     It is also known in the art that the illuminance Lx of a light stream from a light source located perpendicular to an area illuminates that area according to the following relationship: Lx=Lm/m.sup.2. For example, one Lx of illuminance is equal to one Lm of luminous flux for an illuminated surface measuring one square meter in area, and with the light source arranged perpendicular to the surface. In another example, if the luminous flux is equal to 1,000 Lm and the uniformly illuminated surface is one square meter, then the illuminance of that area equals 1,000 Lx. Thus, in order to measure the luminous flux in a uniformly illuminated area of 1.0 square meters, a Lux Meter may be placed anywhere in the illuminated area. 
     Some prior art producers of light sources, e.g., prior art flashlights utilizing light emitting diodes (LED) claim values of luminous flux (Lm) which in some instances appear higher than the maximum value that can be emitted by the light emitting diode in all directions. Such claims do not account for the uniformity of illuminance (Lx) of an illuminated area where the measurement was taken. Experimentally, the illuminance of two prior art LED&#39;s, have been measured and compared to their maximum luminous flux. Two prior art flashlights were chosen for the measurement: (1) ND HB F5, 6V, 2CR 123, 107 Lm Cree LED (hereinafter “HB F5”), and (2) NH HB VIGOUR, 6V, 2CR 123, 107 Lm Cree LED (hereinafter “HB VIGOUR”). Each flashlight having substantially identical electrical specifications, but different optical schematics. The HB F5 appears to utilize an optical schematic that allows for concentrated light emission with uniform luminous flux through the light stream and +/−2.5° angle of dispersion relative to the optical axis. The HB VIGOUR utilizes a focusing output lens system. 
     Other light sources include flashlights which typically comprise a light source, a reflector located behind the light source, a lens or glass in front of the reflector, and a power supply. The reflector and the lens are intended to collect light from the source and collimate or focus the light into a desired beam. Such light sources are often portable, and generally produce a diverging beam of light whereby the brightness varies across the beam. Typically, the light beam is brightness at its center, and drops off dramatically at its peripheral edge. Examples of such prior art lights may be found in U.S. Pat. Nos. 1,823,762, 2,228,078, 4,286,311, and 4,527,223. 
     An important advantage of the present invention is the provision of a light device where the light beam is minimally divergent or compressed along the optical axis, thereby allowing for increased intensity over an illumination range of interest. 
     A number of patents and or publications have been made to address these issues. Exemplary examples of patents and or publication that try to address this/these problem(s) are identified and discussed below. 
     BRIEF SUMMARY OF THE INVENTION 
     The present invention provides a flashlight comprising a power supply, a light source for emitting light, a collecting lens for gathering and compressing the light from the light source, a negative lens for diverging the light, a collimating lens for projecting the light along a ray parallel with an optical axis, and a housing for mounting each component therein. In one embodiment, a flashlight is provided that includes a power supply, a light source, an adjustable collecting lens for gathering and compressing the light from the light source, a negative lens for diverging the light, a collimating lens for projecting the light along a ray at an adjustable angle with an optical axis, and a housing for mounting each component therein. 
     It is an object of the merging light from multiple light sources into a single beam the beams of multiple sources of concentrated light. This provides or light beam that is nearly constant illumination intensity across the beam of light. This reduces or eliminates bight and dim areas that are created from previous light systems that use desecrate lighting elements. 
     It is another object of the menorah configuration to be used for polychromatic light that consisting of or related to radiation of more than one wavelength and for coherent light that is usually monochromatic. The menorah configuration can be used with visible Light, IR and UV wavelengths of light. 
     It is still another object of the menorah configuration design can be used for several layers of single light sources. 
     Various objects, features, aspects, and advantages of the present invention will become more apparent from the following detailed description of preferred embodiments of the invention, along with the accompanying drawings in which like numerals represent like components. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S) 
         FIG. 1  illustrate the illuminated field of a prior art light source. 
         FIG. 2  illustrate the illuminated field in accordance with the present invention. 
         FIG. 3  is graph comparing the illuminance of a prior art light source and a light source formed in accordance with the present invention. 
         FIG. 4  is a schematic representation of a light source arranged in accordance with one embodiment of the present invention. 
         FIG. 5  is a further schematic representation of a light source arranged in accordance with one embodiment of the present invention. 
         FIG. 6  is an elevational, cross-sectional view a light source arranged in accordance with one embodiment of the present invention. 
         FIG. 7  is an elevation, cross-sectional view a light source arranged in accordance with another embodiment of the present invention. 
         FIG. 8  shows an optical schematic. 
         FIG. 9  shows several light sources combined. 
         FIG. 10  shows a schematic drawing showing the light sources on a plane. 
         FIG. 11  shows a section cut through line  331 - 332  from  FIG. 10 . 
         FIG. 12  shows a picture of the light beams as they collectively leave projector. 
         FIG. 13  shows a picture of the convergence of the beams at a distance. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     This description of preferred embodiments is intended to be read in connection with the accompanying drawings, which are to be considered part of the entire written description of this invention. The drawing figures are not necessarily to scale and certain features of the invention may be shown exaggerated in scale or in somewhat schematic form in the interest of clarity and conciseness. In the description, relative terms such as “horizontal,” “vertical,” “up,” “down,” “top” and “bottom” as well as derivatives thereof (e.g., “horizontally,” “downwardly,” “upwardly,” etc.) should be construed to refer to the orientation as then described or as shown in the drawing figure under discussion. These relative terms are for convenience of description and normally are not intended to require a particular orientation. Terms including “inwardly” versus “outwardly,” “longitudinal” versus “lateral” and the like are to be interpreted relative to one another or relative to an axis of elongation, or an axis or center of rotation, as appropriate. Terms concerning attachments, coupling and the like, such as “connected” and “interconnected,” refer to a relationship wherein structures are secured or attached to one another either directly or indirectly through intervening structures, as well as both movable or rigid attachments or relationships, unless expressly described otherwise. The term “operatively connected” is such an attachment, coupling or connection that allows the pertinent structures to operate as intended by virtue of that relationship. In the claims, means-plus-function clauses, if used, are intended to cover the structures described, suggested, or rendered obvious by the written description or drawings for performing the recited function, including not only structural equivalents but also equivalent structures. 
       FIGS. 1 and 2  correspond to the illuminated fields of the HB VIGOUR and HB F5, respectively. Although, the illuminated area of fields is  FIGS. 1 and 2  were each 1.0 m.sup.2, the distance of the flashlights to the illuminated surface varied. HB VIGOUR was located a distance of five meters from the illuminated area, corresponding to illuminated field “ 1   a ”; whereas, HB F5 was located a distance of 10.5 meters from the illuminated area, corresponding to illuminated field of  FIG. 2 . The distribution of illuminance throughout the illuminated fields in  FIGS. 1 and 2  is given by Lx=Lm/m.sup.2 as illustrated by  FIG. 3 . 
     Curve  81  of  FIG. 3  represents the distribution of illuminance of the HB F5 having an illuminated area of 1.0 square meter at a distance of 10.5 meter from the illuminated surface. It can be seen that the maximum luminous flux for curve A is about 135 Lm. Curve  82  of  FIG. 3  represents the distribution of illuminance of the HB VIGOUR having an illuminated area of 1 square meters at a distance of 5.0 meters from the illuminated surface. It can be seen that the maximum luminous flux for curve B is about 80 Lm. Dotted line  83  of  FIG. 3  represents the theoretical maximum luminous flux, 107 Lm, of the LED used in both the HB F5 and HB VIGOUR. 
     The area under curve  81 , S 1 , is calculated as follows: Y=½n exp(−x 2 /2). Solving for S 1  from −56 to +56: .intg.[½n exp(−x 2 /2)] dx=7,795 units. The area under curve  82 , S.sub. 2 , is 112.times.80=8,960 units. It can be seen that S.sub. 1  is smaller than S.sub. 2 , and S.sub. 1 /S.sub. 2 =0.87. Thus, the luminous flux of curve  81  is equal to 87% of 80 Lm which is 70 Lm, but not 135 Lm as some flashlight manufacturer&#39;s claim. Thus the uniformity distributed luminous flux cannot exceed the value of 107 L.sub.m because this value is the maximum output of the LED used in both flashlights. 
     Referring to  FIGS. 4-6 , the present invention provides a flashlight  2  including a lens projection system  4 , a light source  6 , a power supply  8 , and a housing  10 . Although described as a portable flashlight for convenience, the present invention may be used for a wide variety of illumination purposes including spotlights and searchlights. Lens projecting system  4  comprises a collecting lens  22 , a negative lens  24 , and a collimating lens  26 . Each lens  22 ,  24 , and  26  is aligned along a common central optical axis  5  and mounted within housing  10 . Collecting lens  22  defines a first or light gathering surface  31  and a second or light emitting surface  33  that defines a peripheral edge  35 . Collecting lens  22  is mounted between light source  6  and negative lens  24 . First surface  31  is nearly planar and arranged so as to be substantially perpendicular to optical axis  5 . Second surface  33  is generally convex and intersects first surface  31  along peripheral edge  35 . In one exemplary embodiment of the invention, collecting lens  22  is plano-convex with an optical focal length of about 17.5 millimeters and an outside diameter of about 18.0 mm. 
     Negative lens  24  is positioned between the collecting lens  22  and the collimating lens  26 , and defines a first surface  41 , a second surface  43 , and a peripheral edge  45 . First surface  41  is generally convex having a first radius of curvature R 1  ( FIG. 4 ). Second surface  43  is generally concave having a second radius of curvature R 2 , wherein R 1  is greater than R 2 . Peripheral edge  45  is generally cylindrical in shape and defines the outer circumferences of the first surface  41  and the second surface  43 . In one embodiment of the invention, negative lens  24  is a negative meniscus lens having an optical focal length of −150 mm and an outside diameter of 25.0 mm. 
     Referring to  FIG. 5 , collimating lens  26  defines a first surface  51 , a second surface  53 , and a peripheral edge  55 , and is mounted between negative lens  24  and an aperture of housing  10 . First surface  51  is generally convex having a radius of curvature R 3 . Second surface  53  is generally convex having a radius of curvature R 4 . Preferably, R 3  is greater than R 4 . Peripheral edge  55  is generally cylindrical in shape and defines the outer circumferences of first surface  51  and second surface  53 . In one embodiment of the invention, the collimating lens  26  is a biconvex lens having an optical focal length of −132 mm and an outside diameter of 43.9 mm. Lenses  22 ,  24 ,  26  may be formed from any suitable optical material having a refractive index in the range of 1.47214 to 1.74605. Such materials may include glass, polymers, etc. In one embodiment of the invention, lenses  22 ,  24 ,  26  are formed from BK7 optical glass having a refractive index of 1.47214. 
     Light source  6  may be mounted within housing  10  generally along optical axis  5  of lens projection system  4 . Light source  6  is often located a first distance D 1  away from collecting lens  22  along optical axis  5  in such a manner that substantially all luminous radiation emitted by light source  6  falls upon first surface  31  of collecting lens  22 . Distance D 1  will depend upon the type of light source provided, since each light source emits light at various beam angles. Light source  6  may be any suitable light generating structure, e.g., incandescent, fluorescent, light emitting diode, etc. In one preferred embodiment of the invention, light source  6  comprises a light emitting diode of the type known in the art. 
     Referring to  FIGS. 4-7 , housing  10  is shaped and sized so as to enclose and secure lens projecting system  4 , light source  6 , and power supply  8 , while allowing light rays  100 , 101 , 102  to travel from light source  6 , through light projecting system  4 , so as to exit housing  10  via an aperture  107 . Housing  10  may be formed from any suitable engineering material, e.g., metal, polymer, rubber, etc., or any combination thereof. Housing  10  generally comprises a plurality of sections  60 ,  62 ,  64 ,  66 ,  68  centrally disposed about optical axis  5 . First section  60  is generally cylindrical in shape having a first end  90  and a second end  91 , with light source  6  being mounted adjacent first end  90 . Collecting lens  22  is often mounted adjacent to second end  91 . In this way, a light ray  100  may travel through first section  60  from light source  6  and through collecting lens  22  adjacent second end  91 . 
     Second section  62  is generally cylindrical in shape having a first end  92  and a second end  93 , with collecting lens  22  being mounted adjacent first end  92 . Negative lens  24  is often mounted adjacent to second end  93 . In this way, a light ray  101  ( FIG. 4 ) may travel through second section  62  by passing through collecting lens  22  adjacent first end  92  and negative lens  24  adjacent second end  93 . In one embodiment of the invention, second section  62  comprises three sub-sections  70 ,  72 ,  74 . Sub-sections  70  and  74  are cylindrical in shape, but often with different diameters. Sub-section  72  is frusto-conical in shape and intersects sections  70  and  74 . Third section  64  is generally frusto-conical in shape having a first end  94  and a second end  95 , with negative lens  24  being mounted adjacent to first end  94 . Collimating lens  26  is mounted adjacent to second end  95 . In this way, a light ray  102  ( FIG. 4 ) may divergently travel through third section  64  by entering negative lens  24  adjacent to first end  94 , and exiting collimating lens  26  at second end  95 . Fourth section  66  forms a rim to prevent damage to collecting lens  26 . Housing  10  defines an aperture  80  in fourth section  66 . In one embodiment of the invention, aperture  80  may have a diameter of about 50 mm. Fifth section  68  is generally cylindrical in shape and contains power supply  8 . Section  68  is adjacent to first section  60  and is sized to accommodate the power supply  8 . Power supply  8  is often portable and electrically connected to light source  6 . Power supply  8  is not limited to any specific type of battery, i.e., alkaline, NiCad, etc.) and may be selected by one skilled in the art to meet requirements of the invention. 
     Referring to  FIG. 4 , lens projection system  4  creates a preferred light path as defined by rays  100 , 101 , 102  whereby light from light source  6  is influenced by light projecting system  4  so as to be projected as a highly collimated beam exiting aperture  80  of housing  10 . Light source  6  emits light ray  100  which is gathered at first side  31  of collection lens  22 . Collecting lens  22  causes ray  100  to bend so that it follows a path that is nearly parallel to optical axis  5 , resulting in ray  101 . Ray  101  is then projected through negative lens  26 , whereby it diverges from optical axis  5 , resulting in ray  102 . Ray  102  is then collimated by collimating lens  26  and exits aperture  80  at an angle  110  with optical axis  5 . In one embodiment of the invention, the collimated beam exiting aperture  80  may have an angle  110  of +/−2.5° angle with optical axis  5 . Advantageously, since all light emitted by light source  6  is gathered by collecting lens  22 , the projected beam has uniform brightness at all points throughout its cross section. One embodiment of the invention may have a constant beam angle  110  with first distance D 1 , between light source  6  and first surface  31  of collection lens  22 , being about 19 mm. In such an embodiment, second distance D 2 , between collection lens  22  and negative lens  24 , is about 115 mm, and third distance D 3 , between the negative lens and the collimating lens, is about 94.4 mm. 
     Referring to  FIGS. 5 and 7 , an alternative embodiment of the invention provides a flashlight  2  including a lens projection system  4 , a light source  6 , a power supply  8 , and a housing  10 . Light source  6  may be adjusted by a distance D 1  from the lens projecting system  4 , thereby resulting in a variable beam angle  101 . First distance D 1  may be adjusted between about 2.0 mm to about 11.4 mm, resulting in a beam angle  110  of about 0.25 degrees to 2.5 degrees respectively from optical axis  5 . 
     In the alternative embodiment, lens projecting system  4  comprises a collecting lens  22 , a negative lens  24 , and a collimating lens  26 , wherein each lens is aligned along a central optical axis  5  and mounted within housing  10  along optical axis  5 . Collecting lens  22  defines a first surface  31 , a second surface  33 , and a peripheral edge  35  that is mounted between light source  6  and the negative lens  24 . 
     Light source  6  is mounted within housing  10  generally along optical axis  5  of lens projecting system  4 , and is again positioned a first distance D 1  away from collecting lens  22  along optical axis  5  in such a manner that all luminous radiation emitted by light source  6  is projected upon first surface  31  of collecting lens  22 . In the alternative embodiment of the invention, first distance D 1  may be between about 2.0 mm to about 11.4 mm. Also in this alternative embodiment, housing  10  is shaped and sized to enclose and secure lens projecting system  4 , light source  6 , and power supply  8  while allowing light rays  100 , 101 , 102  to travel from light source  6 , through light projecting system  4 , and finally through an aperture  80  at a variable angle  110 . Housing  10  generally comprises a plurality of sections  200 ,  210 ,  220 ,  230 ,  240  centrally disposed about optical axis  5 . Section  200  is generally cylindrical in shape and hollow, having a first end  202  and a second end  204 . A thread  206  is formed on the inside surface of section  200  adjacent to first end  202 . Light source  6  is located within section  200  adjacent to first end  202 . 
     Referring to  FIG. 7 , section  210  is generally cylindrical in shape and hollow, having a first end  212  and a second end  214 . A thread  216  is formed on the outside surface of section  210  adjacent to first end  212  that matingly complements thread  206 . An annular flange  218  projects radially outwardly from the outer surface of section  210  adjacent to second end  214 . A collecting lens  22  is mounted adjacent to first end  212  such that light traveling through first end  212  must pass through collecting lens  22 . Section  220  is general cylindrical in shape and hollow, having a first end  222  and a frusto-conical second end  224 . Section  220  has an internal diameter that is sized to accept annular flange  218  of section  210 . A thread  228  is defined on the inner surface of section  220  adjacent to first end  222 . Section  230  is generally cylindrical in shape and hollow, having a first end  232  and a second end  234 . A thread  236  is defined on the internal surface of section  230  adjacent to a first end  232 , and complementary in pitch to a corresponding thread located on the outer surface of second end  214  of section  210 . Second end  234  of section  230  includes an annular shoulder  238 . 
     Section  240  is a substantially frusto conical, hollow cylinder having a first end  242  and a second end  244 . The inner surface of section  240  comprises a series of recess steps suitable for seating negative lens  24  and collimating lens  26 . Second end  234  of section  230  is sized so as to be received within an opening located at first end  242  of section  240  such that section  240  abuts shoulder  238 . As a result of this construction, negative lens  24  and collimating lens  26 , carried by section  240 , may be adjusted along common optical access  5  by movement of sections  210  and  230  relative to section  220 . 
       FIG. 8  shows an optical schematic. Every source of concentrated light is constructed based on this optical schematic. The lenses  301  and  302  in this figure are a type of light emitting diode  300  and the distances  310  and  311  are determined such that the light emitted by the light emitting diode passes through lenses  301  and  302  and exits lens  302  as a cone of light with homogeneous distribution of light energy is throughout any plane of the light cone perpendicular to the optical axis passing though the centers of lens  301 , lens  302  and the light emitting diode  300 . All of the light emitted by the light emitting diode and passed through lens  301  and lens  302  is found only within the light cone and no light from the light emitting diode is found outside of the light cone. 
       FIG. 9  shows several light sources combined. The optical axes of all light sources are parallel to each other and the whole system comprising the  7  light sources is symmetrical with respect to the center of the whole assembly. In this figure the multiple light sources  320  are secured in a base  321  that maintains the parallel alignment of the multiple light sources  320 . The base  321  is secured to an adjustable base  322  for use as a fixed base, adjustable base or a motorized base  322 . The same would be true for a system comprised of any other number of light sources. 
       FIG. 10  shows a schematic drawing showing the light sources on a plane  331 - 332 . The distances between the centers of neighboring light sources are equal to  330 . Let us chose any three light sources located on the same axis, for example-axis  331 - 332  and let us see what they look like on a plane turned 90° to the plane on  FIG. 11 . 
     It is seen in  FIG. 11  that at distance  343  from the light sources the divergence relative to the central light sources is equal to  342 , and maintains its value independent of any value of  343 . For example, if the beam of each light source has a beam angle of 10°, and  343 =6 meters, then the diameter of every beam will be 1 meter and the circular zone of divergence will be only 50 mm wide (while dimension  342 =25 mm). This means that the zone of complete convergence of the beams is no less than 90% of the whole beam created by the merged individual beams. The light sources can be several layers of single light sources with a first layer of  7  light sources, next layer  12  light sources, next layers  17  light sources, e.t.c. to increase the intensity of the merged beam. 
       FIG. 12  shows a picture of the light beams as they collectively leave projector, and  FIG. 13  shows a picture of the convergence of the beams at a distance. The light can be polychromatic light that consisting of or related to radiation of more than one wavelength and for coherent light that is usually monochromatic. The menorah configuration can be used with visible Light, IR and UV wavelengths of light. 
     Thus, specific embodiments of a compact searchlight utilizing the merging of multiple single beams to a concentrated light have been disclosed. It should be apparent, however, to those skilled in the art that many more modifications besides those described are possible without departing from the inventive concepts herein. The inventive subject matter, therefore, is not to be restricted except in the spirit of the appended claims.