Patent Abstract:
A flashlight is disclosed which includes a housing adapted to receive one or more battery cells and having a transparent lens on a forward end thereof. An LED light source connected to the cell is utilized in conjunction with collimating optics positioned adjacent the LED to refract rays of light from the LED forwardly. A first paraboloid reflector having a concave reflective surface is positioned within said housing to receive rays of light from the collimating optics and to reflect the rays rearwardly and a second paraboloid reflector having a concave reflective surface is positioned within said housing to receive rays of light reflected rearwardly from the first paraboloid reflector and to further reflect the rays forwardly through the transparent lens.

Full Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to a flashlight. More specifically, it relates to an extremely durable and long lasting flashlight utilizing a light emitting diode (hereinafter “LED”) light source in combination with a pair of paraboloid reflectors making the flashlight particularly useful for police, fire, rescue and emergency services workers and military personnel. 
   2. Description of the Prior Art 
   A variety of prior art flashlights have been proposed. 
   Matthews, U.S. Pat. No. 6,386,730, discloses a flashlight having a head with two merged yet independent lamp/reflector systems. While Matthews teaches the provision of two reflectors, both reflectors are simply used to independently focus light from two light sources into the forwardly directed beam configurations. 
   McDermott, U.S. Pat. No. 5,894,196, discloses a compact lighting device including a light concentrating reflector directing light emitted by a light source toward a curved light refracting surface where it is refracted and thereby redirected. McDermott teaches the generation of substantially elliptical patterns of light. 
   Sharrah et al., U.S. Pat. No. 5,871,272, discloses a flashlight having a lamp head including a reflector having a major paraboloid reflective surface and a minor reflective paraboloid surface not interacting on the same light source. 
   Matthews et al., U.S. Pat. No. 6,046,574, discloses a flashlight having a first cell or set of cells (batteries) arranged in a first pattern and alternatively a second cell or set of cells (batteries) arranged in a second pattern with switching between or interconnecting the two cells or sets of cells disclosed. An on off switch is provided which includes a push button switch and a rotary switch that blocks the on off push button switch. A momentary on switching function is provided. A flashlight beam is cast with a first lamp and reflector and an alternative second lamp and reflector assembly is substituted for the first lamp and reflector to provide a different configuration of beam illumination. 
   Lebens et al., U.S. Pat. No. 6,095,661, discloses an LED flashlight which includes a control circuit that selectively applies power from a source of electric power to the LEDs, thus maintaining or controlling the light output level of the LEDs at a generally constant level as the charge on the battery cell varies. 
   Copeland, U.S. Pat. No. 5,015,918, discloses a bicycle lighting system utilizing red LEDs which includes a means to maintain the charging current at a relatively constant average value thus supplying a constant current and power to the LEDs. 
   Krietzman, U.S. Pat. No. 5,909,062, provides an LED flashlight which has a second or redundant battery supply which nests in-line in a tubular or oval housing. 
   Sinclair, U.S. Pat. No. 6,331,062, discloses a portable electric LED flashlight having a light source in the form of an LED with a high internal resistance. The use of such a high resistance element, while initial costs are low, is undesirable as it unnecessarily wastes battery power. 
   There remains a need for a high intensity light LED powered flashlight which is highly efficient and long lasting for use by fire fighting personnel, law enforcement personnel, EMS personnel and civilians and the like. 
   SUMMARY OF THE INVENTION 
   The present invention provides a flashlight which, in its preferred form, is intended to run continuously over a 10 hour period or more on one set of “D” cells or over 20 hours on 2 sets. It will be obvious that any size of cells can be utilized and it currently contemplated that a smaller version of the flashlight which utilizes 2 sets of “AA” cells would be of particular utility although, with smaller cells, the number of hours of continuous illumination without replacement of cells would be significantly fewer. A second microprocessor controlled circuit allows the flashlight to switch from one set of cells to the other, which provides uninterrupted use. An indicator is provided to show which set of cells is in use and, preferably, to also show the degree to which such cells have been drained. A new set of cells can replace the drained set while the flashlight is in use. A microprocessor circuit also allows the light to remain bright white throughout the life of the cells. The flashlight uses a pair of paraboloid reflectors that work together to focus the light into a concentrated beam. The housing of the flashlight is made from a high strength polycarbonate material. An emergency strobe light is preferably imbedded into the handle of the flashlight. A sliding thumb switch activates the LED or the strobe. The switch is hermetically sealed to enable the unit to be water resistant. The flashlight can be placed in several positions using a multi-position stand which is mounted to the bottom of the housing. The multi-position stand also features a retractable stainless steel split ring to allow the user to attach the flashlight to many devices including the key ring holders that many of the above personnel utilize. The split ring may be used in conjunction with the multi-position stand to suspend the flashlight in a variety of positions. The flashlight is preferably sealed with o-rings making the flashlight water resistant. 
   The present invention has a number of specific objects and features including but not limited to the following: 
   Presently, a single one watt bright white LED light source is preferred. A five watt bright white LED light source is also contemplated. 
   The LED light source is intended to have a long operating life of up to 100,000 hours. 
   It is an object of the invention to provide a flashlight which provides non-dimming light throughout the life of the cells. 
   It is an object of the invention to utilize two paraboloid focusing reflectors to direct a concentrated light beam. 
   It is an object of the invention to utilize two sets of cells with one working set and one auto switched back-up set. 
   It is an object of the present invention to provide the switching from one cell set to the other with a microprocessor controlled circuit. 
   It is also an object of the invention to utilize a second microprocessor controlled circuit to maintain a generally constant LED current with thermal input over a temperature range of approximately −40° to 120° F. 
   It is an object of the invention to allow for the replacement of one set of cells without interruption of the light. 
   It is an object of the invention to provide an emergency strobe light imbedded in the housing or the handle of the flashlight. 
   It is an object of the invention to provide a hermetically sealed switch. 
   It is an object of the invention to provide a multi-position stand which is pivotally mounted for 180 degrees of rotation. 
   And it is an object of the invention to provide a retractable stainless steel split ring for belt attachment or the like. 
   The flashlight of the present invention preferably comprises a housing adapted to receive at least one cell and having a transparent lens on a forward end thereof; an LED light source adapted to be connected to said at least one cell, said LED light source when energized emitting rays of light in a generally hemispherical light pattern; collimating optics positioned adjacent said LED to direct (by refraction or reflection or both) said rays of light into a first generally cylindrical pattern of light with light rays being generally parallel to one another and directed in a forward direction along an optical axis; a first paraboloid reflector having a concave reflective surface positioned within said housing and preferably attached to an inner side of said transparent lens, said first paraboloid reflector having a focus point positioned on said optical axis and positioned to receive rays of light from said first generally cylindrical pattern of light and to reflect said rays rearwardly generally through said focus point; and a second paraboloid reflector having a concave reflective surface positioned within said housing and having a focus point positioned on said optical axis to receive rays of light reflected rearwardly from said first paraboloid reflector and to further reflect said rays into a second generally cylindrical pattern of light with light rays being generally parallel to one another and directed in a forward direction along an optical axis and out of the housing through said transparent lens. 
   Preferably said focus point of said first paraboloid reflector and said focus point of said second paraboloid reflector are located at the same point along said optical axis. 
   Preferably, said at least one cell further comprises at least two cells which are controlled by a first microprocessor control circuit to independently energize said LED light source at different times. Preferably said at least one cell further comprises at least two pairs of cells. 
   The flashlight of the present invention preferably has a housing which further comprises a stand pivotally mounted thereon. Said stand preferably may rotate though 180 degrees of rotation to allow said flashlight when laid upon a surface to selectively direct light a number of different directions. Preferably, said stand further comprises at least two toothed disks urged together by at least one wave spring washer whereby said stand is restrained from pivotal motion by said toothed disks unless force is applied to said stand sufficient to overcome the force applied by said wave spring washer. Said stand also preferably includes a spring loaded ring which is urged to remain in a secured location which prevents rotation thereof absent the application of force and upon the application of force said ring moves away from said secured location and is free to rotate relative to said stand. 
   The flashlight housing preferably includes a handle for carrying said flashlight. 
   Preferably, the flashlight also further comprises a strobe light in said housing or in said handle. 
   The flashlight preferably has a switch to selectively energize said LED light source. The switch is preferably a four position switch including an LED on position, a spring loaded momentary LED on position, an off position and a strobe on position. The switch is preferably hermetically sealed. 
   A second microprocessor control circuit is preferably provided to produce a generally constant electrical current to the LED light source. Preferably, such circuit provides a generally constant current over a range of temperatures between −40 degrees F. to 120 degrees F. Finally, the LED light source is preferably mounted on a heat sink to remove heat from said LED light source. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is an isometric view of the front of the flashlight of the present invention. 
       FIG. 2  is a cross sectional view showing the collimating optics, first paraboloid reflector and second paraboloid reflector and a single ray of light directed thereby. 
       FIG. 3  is a cross sectional view of the collimating optics, first paraboloid reflector and second paraboloid reflector showing the paths of three different rays of light. 
       FIG. 4  is an isometric view showing the rear of the flashlight of the present invention. 
       FIG. 5  is an isometric view showing the flashlight attached to the belt of an emergency services worker. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   Referring to the figures, the flashlight  10  has a housing  20 . The housing  20  has a cell compartment  42  which can be accessed by a pair of end caps  22 . A rubber o-ring  23  is preferably provided on each end cap  22  to provide a water resistant means to enclose the cells  40  within the housing  20 . A pair of cylindrical (rather than typical conical) shaped coil springs  41  are utilized to firmly hold the cells  40  in electrical contact with the necessary components to illuminate LED  30  or strobe  80  when desired. The housing  20  also includes a transparent lens  24  on the front end of the housing and a carrying handle  26  is provided. 
   A one watt bright white light LED light source  30  is provided. Collimating optics  50  are attached adjacent said LED light source  30 . A first paraboloid reflector  60  is provided on an inner surface of transparent lens  24 . Depending upon the desired location for the focus point F 1  of the first paraboloid reflector  60 , however, it may be necessary to mount said first paraboloid reflector with the housing  20  at a location rearwardly of the inner surface of transparent lens  24 . As is well known, the location of focal point F 1  will be closer to the first paraboloid reflector if the curvature of the paraboloid reflector is great and further away as the curvature becomes more flattened with F 1  located at infinity with a planar paraboloid surface. 
   A second paraboloid reflector  70  is also provided on the inner surface of transparent lens  24  as best shown in  FIGS. 2 and 3 . A multi-position stand  100  is mounted to the lower side of housing  20 . The multipurpose stand  100  includes a pair of legs  102 , a cross member  104  and a front end portion  106  formed in a semi-annular configuration. The front end portion  106  includes a semi-annular groove  108  which is adapted to receive a stainless steel split ring  120 . A split ring  120  is attached to a release button  110  which is urged by spring  112  to secure ring  120  in groove  108 . When outward force is applied to ring  120 , ring  120  moves outwardly away from end  106  and is then free to rotate as it is then outside of groove  108 . The rotation of ring  120  is best shown in FIG.  5 .  FIG. 1  shows ring  120  as secured in groove  108 . 
     FIG. 5  shows the ring  120  attached to an emergency service worker&#39;s utility belt  200  by means of a clip  202 . It is noted that the stand  100  is adapted to rotate through 180° of rotation. When rotated rearwardly in the direction of arrow R shown in  FIG. 4 , the stand may extend outwardly from the rear of the flashlight as shown in FIG.  5 . When the stand is moved forwardly in the direction of arrow F in  FIG. 4 , it is adapted to lie flat against the lower portion of the housing  20  to allow the flashlight to have a compact storage configuration. A variety of intermediate positions can be selected so that the light from the flashlight may be directed in a desired direction. 
   The legs  102  are pivotally mounted in the base  101  of stand  100  by means of a screws or rivets  118 . A pair of toothed discs  114  in combination with a wave spring washer  116  are utilized to restrain the stand from pivotal motion unless forces applied to said stand sufficient to overcome the force applied by said wave spring washer. This allows any one of a desired of rotational positions to be selected and for the stand to remain firmly affixed to said selected position until sufficient force is applied to move it to a different position. 
   The handle  26  on the flashlight preferably has a strobe light  80  embedded therein as shown in  FIG. 1. A  hermetically sealed four position thumb switch  90  is also provided on handle  26 . 
   A first microprocessor controlled circuit  44  is provided to control the switching from one set of cells to the other. A second microprocessor controlled circuit  45  is provided to provide generally constant current to the LED  30  over a broad range of temperatures. 
   Referring now specifically to  FIGS. 2 and 3 , the LED  30  is provided on a heat sink  32  and collimating optics  50  are provided adjacent thereto. Preferably, the LED and collimating optics are assembled as a single unit such as, for example, the commercially available product sold under the trademark “LUXEON STAR/O” which is the presently preferred LED light source/collimating optics element. The first paraboloid reflector  60  and the second paraboloid reflector  70  are preferably formed of molded plastic and are then metallized by either a vacuum metallization process or by sputtering to create a highly reflective paraboloid surfaces  61  and  71 , respectively. 
     FIG. 2  specifically shows the path of a ray of light identified as R 1  as it travels from the light source  30  until the time that it passes forwardly through the transparent lens  24 . Ray R 1  first travels radially outward from source  30  as shown by segment R 1 A. The collimating optics  50  utilize the principals of refraction and reflection to direct the R 1  into a path R 1 B which is parallel to an optical axis labeled A. Ray R 1  at the end of segment R 1 B strikes the metallized surface  61  of the first paraboloid reflector  60  is reflected through a focus F 1  of said paraboloid reflector  60  onto the metallized surface  71  of the second paraboloid reflector  70 . This path is designated as R 1 C. Ray R 1  is then finally reflected off of said surface  71  of the second paraboloid reflector in the forward direction of segment R 1 D. Segment R 1 D is also parallel to the optical axis A. As shown in  FIG. 2 , the focus F 1  of the paraboloid reflector  60  is shown to be located in the same position as the focus F 2  of the second paraboloid reflector  70  which is the presently preferred embodiment of the invention. Both of these focuses F 1  and F 2  are located on the optical axis A. It is also contemplated that F 1  and F 2  may be located at different spaced apart locations on the optical axis A. 
     FIG. 3  shows a similar pathway for three rays of light designated respectively as R 1 , R 2  and R 3 . As can be seen by looking at segments R 1 B, R 2 B and R 3 B, as the light rays R 1 , R 2  and R 3  leave the collimating optics element  50 , such rays of light form a first generally cylindrical pattern of light which is directed toward the first paraboloid reflector  60 . It can also be seen that after being reflected off from second paraboloid reflector  70  said rays of light R 1 , R 2  and R 3  form a second generally cylindrical pattern of light, as shown by ray segments R 1 D, R 2 D and R 3 D. 
   Said second generally cylindrical pattern of light forms a concentrated beam of light which provides uniform illumination over the entire circular area to which the cylindrical beam of light is directed. Obviously, because of imperfections in the optics and because of refraction which occurs at each surface, the light beam is not limited solely to the cylindrical beam described herein and some portion of the light generated by said light source  30  will spread over a larger area. 
   While it is preferred that the collimating optics  50  generate a first generally cylindrical pattern of light rays and that the second paraboloid reflector  70  generate a second generally cylindrical pattern if light rays, such light patterns are not required. While such cylindrical patterns of light rays are believed to provide the greatest degree of concentrated illumination at the greatest distance, it is also contemplated that some situations may desirably require a larger area to be generally illuminated rather than providing only a concentrated beam of light rays. By varying the shape of the paraboloid reflectors (and location of F 1  and F 2 ) it is a simple modification to cause said second generally cylindrical pattern of light to be altered to form a generally conical pattern of light, thus allowing for illumination of a larger area. It is also contemplated that by providing a means to move to location of one or more of the paraboloid reflectors along the optical axis (and the location of F 1  or F 2 ) it is possible to allow for an adjustment of the concentration of the beam from the flashlight from a narrow to a wide beam by methods which are well known in the art. 
   Because of the use of a low energy LED coupled with the unique arrangement of paraboloid reflectors and independent dual power supply, the present invention provides an extremely useful flashlight for fire, police and other emergency service workers. The light is intended to provide illumination during an extended period without interruption. Further, since cells can be replaced on the fly without turning the light off, no interruption of illumination will occur. The provision of a strobe light in the handle makes an extremely effective signal to mark danger or to allow emergency helicopters to locate the sight of an emergency event. Finally, because of the durability of each of the components utilized, the flashlight will continue to provide illumination even when subjected to substantial trauma, abuse or adverse conditions. 
   While we have shown and described the presently preferred embodiment of our invention, the invention is not limited thereto and may be otherwise variously practiced within the scope of the following claims:

Technology Classification (CPC): 5