Abstract:
A portable emergency light for long range detection by flight and marine search and rescue personnel which utilizes a battery-powered laser array mounted and sealed within a waterproof housing to increase the effective intensity of a specific class laser. The laser array includes a plurality of laser light generators mounted together to project substantially along a common optical axis producing a signaling light. The search and rescue light may include a rotatable head for directing the signaling lights along a 360° plane and a three-dimensional gimbal which maintains the light beams in a level horizontal position so that the signaling lights may be easily projected along the entire horizon relative to the user. Each laser light generator is within US Government safety standards for the specific class laser despite the increased power of the signal. The laser array can be used with optical alignment lenses to form a desired highly visible light pattern.

Description:
BACKGROUND OF INVENTION 
     1. Field of the Invention 
     The present invention relates to any field that could benefit from a more powerful and more visible laser that has improved range. One specific field is the field of emergency search and rescue lights for use by imperiled individuals who are lost, and specifically to emergency rescue lights utilizing laser technology for enhancing visual detection by search and rescue (SAR) personnel in aircraft or marine vessels searching for an imperiled individual using the rescue light. The present invention provides an improved laser system that has increased power, visibility, and range, beyond what is presently in existence today for a particular class of laser. More specifically, a laser system in which the result is increased power, visibility, and range, without having laser radiation in excess of the accessible emission limits stated in 21 CFR Part 1040.10 for a particular class laser (e.g. a more powerful class I laser or a more powerful class IIIa laser). 
     2. Description of Related Art 
     Portable emergency rescue lights used by an imperiled person trying to be found typically utilize incandescent or strobe lights for visual detection and recognition by searching airborne or marine personnel. The illumination intensity of incandescent lights used in emergency signaling lights is often limited in time, range, and available power and can often be inadequate for detection and signaling purposes. Strobe lights can have a greater visual detection and illumination range than incandescent lights but also have intensity limits. Strobe lights are pulsed and not a steady beam of light. Strobe lights can often have a night blinding effect on the user and rescue personnel. 
     The light bulb power consumption and the amount of battery power available in a portable survival light limits the amount of “on” time and available watts in a survival scenario. The amount of battery time available for illumination can be a critical variable in a survival situation. 
     The present invention provides an improved portable, battery-powered survival light that does not employ either strobe or incandescent bulbs but instead uses a laser light source and laser generator. Advantages of laser light are beam focus, high light intensity and low power consumption. These advantages enable a laser light beam to be continuously visible at great distances for greater time periods. One drawback of using a class IIIa laser light in a search and rescue scenario is that the laser beam of light is so small that at long range, the visible beam area is small and must pinpoint the rescue aircraft or searching vessel; otherwise the laser light will not be seen by the searching personnel. A line generating lens may be used but the loss in intensity is too great. Another perceived drawback of the use of laser light is potential eye damage to users. U.S. Government regulations limit the maximum watt emission level of over-the-counter laser light products, which ensures a level of radiation below the accessible emission limits for a class IIIa laser. 
     The present invention provides a survival light of high intensity, low power consumption, and improved range visibility that complies with U.S. Government safety regulations for over-the-counter sales. 
     SUMMARY OF INVENTION 
     An emergency rescue light utilizing a plurality of laser light generators contained within a waterproof housing. The signal light includes multiple laser light generators, batteries, and a light circuit all of which are enclosed and sealed within a waterproof housing having a lens which allows light emitted from the enclosed laser light generators to pass through to the outside. In the preferred embodiment, off-the-shelf laser light beam generators that meet U.S. Government regulation for safety are used. For human optical safety reasons each laser light beam source cannot exceed the accessible emission limits contained in CFR 21 Part 1040.10 class IIIa laser(5 milliwatts in power). 
     Multiple laser light generators are mounted together and aligned substantially parallel to radiate individual light beams, all in substantially the same direction to form a laser array. The pattern generated by the laser array can be tightened (less space between beams) by the use of a prism, mirror or lens. Each of two laser light generators or more can be slightly angled towards the other so that the laser light beams emitted converge at a point at a fixed distance away from the laser array source (line of sight to the horizon) so that maximum combined total light energy is produced at a desired range, while not combining early enough to exceed the accessible emission limits for a specific class laser (e.g. one class IIIa laser). One or more lenses or reflective surfaces may also be used to spread the beam vertically, usually called a line-generating device. These techniques may be combined for maximizing the visibility of the laser signal to a distant person. 
     The laser arrays are enclosed by a waterproof housing that incorporates one or more transparent lenses, prisms, or mirrors. The multiple laser light beams emitted from the laser array are directed outwardly through one or more lenses, mirrors or prisms, which can provide optical convergence or divergence of the laser light beams producing desirable intensity patterns at a prescribed distance, such as line-of-sight (LOS) to the estimated horizon. 
     One or more batteries sufficient to energize the laser array are electrically connected and mounted within the housing. A power control circuit incorporating an on/off switch connects the laser light beam generators and batteries so that the laser light beam generators in the laser array may be energized by closing the switch. 
     In the preferred embodiment the waterproof housing includes a rigid base and a laser light support platform. The base is elongated, square and open at the top end. The light platform closes the open end of the base. The light platform incorporates a freely rotatable array cylinder attached to a mount head which contains a mirror and lens, that rotates 360° . The mirror is angled relative to the base so that laser light beams emitted from the laser array contained within the base are reflected to pass through the lens. A motor mounted within the base rotates the cylinder from within. The rotation allows the laser light beams reflected by the mirror to be projected 360 degrees horizontally so that the signaling/detecting light produced covers 360 degrees of the surrounding horizon when directed parallel to the ocean surface. 
     The light array control circuit is also connected to the rotating motor so that when the laser array is energized, the motor is also energized. The base encloses the motor, batteries and power control circuit and is sealed at the top end by the attachment of the light platform. 
     The entire waterproof light assembly may be mounted within a portable, handheld, two degree of freedom leveling gimbal. The housing is pivotally attached to an inner gimbal which is mounted within an outer gimbal so that the light assembly housing is maintained by gravity in a level horizontal position when held by the user or mounted on a vessel. A handle is attached to the outer gimbal to facilitate the operation of the signal light by one person. The motor rotates the cylinder effectively projecting the signaling light produced in a 360° horizontal pattern for maximum surface visibility. 
     In an emergency situation in the ocean, the user would typically be in a raft and would turn on the power switch and grasp the gimbal handle to allow the laser beam array to rotate parallel to the earth&#39;s surface for 360° rotation, covering the entire horizon. The gimbals keep the light array horizontal regardless of raft motion. The user could manually grasp the entire housing to override the gimbal and direct the light beam in a specific direction. Preferably, individually emitted laser light beams are each aligned relative to each other to converge roughly on the observable horizon relative to the user in the raft about eight miles from the user source (line of sight) for optimum light energy area distribution and sighting. The gimbals could include an engageable lock to permit manual manipulation of the device to aim the light array manually at a non-horizontal angle. 
     In an alternate embodiment of the invention, the laser light array is mounted within a flashlight housing formed by an elongated cylindrical body and a projection lens mounted head at one end. The elongated cylindrical body houses the batteries, power switch, and light circuit. A laser array of two or more laser light beam generators is housed and contained within the housing adjacent the lens head, transmitting light emitted from the laser generators to pass through the lens. Laser light beams emitted from the laser array are aligned, possibly using prisms, lenses or mirrors to project outwards through the lens substantially along a plurality of parallel axes distributed in a clustered pattern and through a lens for spreading the beam vertically, allowing the sweeping of the horizon with the signal. 
     The light beams emitted from the laser array may be parallel or may be individually angled relative to the optical array axis when passing through the transparent lens for controlling the total light energy in a greater area at a prescribed distance from the light source. The arrangement of the laser light beam generators may be adjusted to form a specific pattern. The lens can cause the multiple laser beams mounted parallel to each other to slightly converge or to diverge to cover a wider area at a distance from the source. From a low position above the earth&#39;s surface, such as a raft or small boat, the line-of-sight horizon is approximately 6 to 8 miles. The multiple light beams can be caused to diverge slightly so that at the LOS horizon, a larger area of the beams is observed. Conversely, the beams can be made to converge slightly for maximum light energy at the LOS horizon, but reduced beam area. 
     In yet another embodiment of the invention the laser light beams emitted from the laser array are each manipulated by a prism so that the laser light beams are aligned along a straight reference plane. The laser light sources are affixed together in a defined geometrical pattern, such as two rows of six lights each, and when used in conjunction with an optic lens, the resultant total beam can be controlled and oriented as to the width of the beam, the fantail or spread distance of the beam, and the spatial relationship of the individual light sources. 
     It is an object of this invention to provide an emergency rescue light that utilizes multiple laser light sources mounted together in a laser array to produce a rescue signal light easily detectable at great distances from the source while in compliance with U.S. Government regulations. 
     In accordance with these and other objects which will become apparent hereinafter, the instant invention will now be described with particular reference to the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF DRAWINGS 
     FIG. 1 is a perspective view of the preferred embodiment of the invention. 
     FIG. 2 is a partially exploded, perspective view of the preferred embodiment of the invention (shown without the gimbal and handles for clarity). 
     FIG. 3 is a perspective view of an alternate embodiment of the invention. 
     FIG. 4 is an exploded, perspective view of the alternate embodiment of the invention shown in FIG.  3 . 
     FIG. 5 shows a schematic diagram (top plan view) using twelve laser light sources each in conjunction with its own single alignment right angle prism in order to alter the resultant total light beam formed by the lasers into a tight pattern of parallel beams. 
     FIG. 6 shows a perspective view of the device schematically represented in FIG.  5 . 
     FIG. 7A shows a schematic diagram of two of the initial laser light arrays shown in FIG. 5 converging prior to altering the resultant laser pattern through a lens or reflector for use in any of the embodiments listed. 
     FIGS. 7B and 7C show two schematic diagrams, the former showing a beam pattern array with five lasers and the latter a beam pattern with 7 lasers. 
     FIG. 8A shows a schematic diagram illustrating the preferred light pattern array from the laser array shown in FIG. 6 with the addition of line forming lenses for a vertical spread a certain distance away, most likely 8 or so miles for the second preferred embodiment. 
     FIG. 8B shows a schematic diagram of the interaction of two separate laser beams, each acted on by a line forming lens, the two beams overlap to form a single beam having two times the intensity at a distance from the laser generators to form a vertical line. 
     FIG. 9A shows perspectively and schematically an alternative embodiment of the invention. 
     FIG. 9B shows a back elevational view of the embodiment of FIG.  9 A. 
     FIG. 9C shows a side elevational view of the embodiment of FIG.  9 A. 
    
    
     DETAILED DESCRIPTION 
     Referring now to the drawings, and more particularly to FIG. 1, the preferred embodiment of the invention  10  is shown. The rescue light  10  basically includes laser light beam generators  28  (shown in FIG.  2 ), housing  15 , and gimbal assembly  50 . Housing  15  is constructed from a rigid, plastic, rectangular base  14  attached to a laser light support platform  12 . Base  14  is elongated and rectangular in shape and has an open top connected to base  14 . Light support platform  12  attaches to base  14  using screw fasteners, glue or other suitable fastener for closing and providing a water tight seal around the open end of base  14 . Base  14  and light support platform  12  may be made of a suitable durable rigid, waterproof material such as plastic, fiberglass or metal. 
     Housing  15  is supported by a two-dimensional or two-degree of freedom gimbal assembly  50  (including handle  52  connected to gimbal arm  50   b ) formed by an inner gimbal support  50   a  and an outer gimbal support  50   b . Housing  15  is mounted within an inner gimbal  50   a  that encircles the housing  15  and housing  15  is pivotally attached at two opposing locations  52   a  and  52   b  so that the housing  15  may pivot freely within inner gimbal  50   a  about a first axis. Inner gimbal  50   a  is mounted within a fork-shaped outer gimbal  50   b  pivotally attached at two locations  54   a  and  54   b  so that inner gimbal  50   a  may pivot freely within outer gimbal  50   b  about a second axis which is perpendicular to the first axis. Both inner gimbal  50   a  and outer gimbal  50   b  may be constructed from a lightweight, rigid material such as aluminum, plastic or other suitable material sufficient to firmly support housing  15 . Outer gimbal  50   b  is attached directly to handle  52 . 
     Referring now to FIG. 2, within base  14  are mounted battery  22 , on/off power switch  24 , DC-powered electric motor  26 , laser array  28 , and power control circuit  30 . Multiple laser light beam generators  28   a  through  28   g , each beam aligned with its own 90 degree prism p to redirect each laser beam 90 degrees are mounted together to form a seven laser generator array  28  which produces a high intensity rescue signal/detection light. Battery  22  is connected electrically to energize laser array  28  and motor  26 . Power control circuit  30  is formed by conductive wires that electrically connect battery  22 , on/off power switch  24 , motor  26  and laser array  28  so that when switch  24  is closed, motor  26  and laser array  28  are energized. When energized, laser generator array  28  generates beams of laser light at a predetermined wavelength. Switch  24  is mounted for manual operation outside base  14 . 
     A mount head  40   a  is attached to one end of a hollow light tube  40 . Rigid hollow light tube  40  extends through a circular aperture  12   a  in light support platform  12  and is rotatably attached to light support platform  12  with a seal and bearings (not shown) so that the mount head  40   a  can be driven to rotate 360° relative to the upper surface of light support platform  12 . A transparent, line generating lens  42  is mounted within an aperture  40   b  within mount head  40   a  which allows the laser light beams emitted from laser generator array  28  to be reflected by mirror  44  to be altered into a vertical line pattern by lens  42 . Mirror  44  is mounted within mount head  40   a  adjacent to lens  42 . Mirror  44  is mounted at a 45 degree angle with lens  42  so that laser light beams projected by laser array  28  through array cylinder  40  are reflected by mirror  44  to project out through lens  42 . The rotation of array cylinder  40  by motor  26  and gear  26   g allows the signaling light produced by laser array  28  to rotate and cover 360 degrees. Six laser light beam generators  28   b ,  28   c ,  28   d ,  28   e ,  28   f  and  28   g  are physically positioned facing inward in a circular array, each so that laser light rays or beams emitted by laser light beam sources  28   b  through  28   g  are directed by prisms p through circular aperture  12   a . Laser generator  28   a  is the seventh laser generator and is positioned in the center of the array  28  facing upward (without a prism p) directing its beam through circular aperture  12   a . The resultant tight cluster light beam pattern is reflected by mirror  44  and projects out through line generating lens  42 , forming a vertically oriented, light line pattern about 100 feet high at a distance of about 8 miles from the source for enhanced detection by a boat on the ocean surface. The distance from the source and pattern of the light sources determine the cross-sectional area of the signaling/detection light, which is very important for visual detection miles away. The larger the cross-sectional area footprint, the greater area of exposure. Laser array  28  is mounted within base  14  relative to array cylinder  40  so that the signaling light beams projected by laser array  28  are directed through array cylinder  40  along an axis parallel to the axis of rotation of array cylinder  40 . In operation, laser light beams are projected by laser array  28  through array cylinder  40  and reflected by mirror  44  through lens  42  along an axis parallel to the plane created by the top of light support platform  12 . Each laser generator  28  through  28   g  is selected so that its power output does not exceed government safety requirements. 
     The distal end of array cylinder  40  (away from mount head  40   a ) has a cylinder peripheral gear  40   g . The shaft of electric motor  26  is connected to a motor gear  26   g  of corresponding pitch that engages with the cylinder gear  40   g . Electric motor  26  is mounted within base  14  and light support platform  12  such that motor gear  26   g  engages cylinder gear  40   g , causing the motor  26  to rotate array cylinder  40  when energized. The 360° rotation of mount head  40  allows the projected light beams to radiate 360° along the horizon. 
     As shown in FIGS. 1 and 2, battery  22 , laser array  28  and motor  26  are mounted within base  14  and light support platform  12  in a balanced arrangement so that when handle  52  is grasped by the user, the top of light support platform  12  is maintained in a level, horizontal position by gravity caused by the freedom of rotation about the first and second gimbal axes and the greater weight of the closed end of base  14  which contains battery  22 , laser array  28  and motor  26 . 
     Referring now to FIGS. 3 and 4, an alternate embodiment  11  of the invention is shown. Laser light beam generator array  27  (FIG. 4) is mounted in a tubular, hand-held, flashlight-like enclosure. The rescue light  11  basically includes a housing or enclosure  23  and a laser light beam generator array  27 . Laser light beam generator array  27  is formed by multiple laser light generators  27   a  through  27   g  and prisms P 1 . 
     Rescue light  11  is made from a rigid, waterproof material such as plastic or metal. Rescue light  11  is formed by an elongated cylindrical body  23  and a removable projection head  25 . Body  23  is open at the first end and closed at the second end. Body  23  encloses batteries  34   a  and  34   b , a spring  36 , an electrical power switch  38 , and power array circuit  37 . Batteries  34   a  and  34   b  are connected together electrically so that sufficient energy is produced to energize laser light beam array  27 . Electrical power switch  38  is mounted for operation on the outside of body  23 . Power array circuit  37  electrically connects batteries  34   a  and  34   b  with electric power switch  38  and laser light beam generator array  27  so that when electrical power switch  38  is closed, laser light beam generator array  27  is energized, generating beams of laser light at a predetermined wavelength. Projection head  25  is open at the first end and closed and sealed at the second end by projection lens  25   b . Projection head  25  encloses laser light beam array  27  and right angle prisms P 1  by threadable connection (threads  25   c ) to body  23 . The outside surface of the opening of the first end of body  23  is adapted with fastening threads  23   f . The inside surface of the first end of projection head  25  contains receiving threads  25   c  of the corresponding pitch to permit engagement with fastening threads  23   f  located at the first end of body  23 . Further, the inside surface of the first end of projection head  25  contains a seat for accommodating o-ring seal  25   a  contained within. The outside surface of body  23  may be machined to provide a rough, grooved surface for easy gripping. Cap  25   d  screws on to head  25  at threads  25   e  and includes line forming lens  25   b . Cap  25   d  and lens  25   b  are made water tight. 
     Rescue light  23  is assembled by engaging fastening threads  23   f  and receiving threads  25   c  and rotating projection head  25  until body  23  is sealed by projection head due to the compression of o-ring seal  25   a  between projection head  25  and handle  23 . A seven laser light beam pattern  256  is represented at the opening of head  25  showing how the laser light beams are aligned in parallel with seven beams, six in a circular cluster with a seventh beam in the center. When these seven beams in array  256  pass through line forming lens  25   b , a line or single band of laser light is produced. The laser generator array  27  is comprised of seven laser generators, six facing inward in a circular pattern, each with its own right angle prism P 1  and a seventh in the center directing its beam toward lens  25   b . The purpose is to provide a tight light pattern that is altered through circular cylinder lens  25   b  into a line which can be swept across the horizon or at an aircraft to aid in being detected by search and rescue crews miles away. The power of each laser generator in array  27  is selected to not exceed government safety requirements. 
     Line forming lens  25   b  receives light emitted from laser light beam array  27  contained within projection head  25  and creates a single line that can be 100 feet long at eight miles. Laser light beam generator array  27  is mounted and positioned within projection head  25  so that the individual laser light beams emitted by laser generator array  27  are directed away from the second end of body  23  substantially parallel to an optical axis which is parallel with said body  23  through projection lens  25   b.    
     Referring to FIG. 3, rescue light  11  is shown fully assembled except for cap  25   d  and lens  25   b . In use, the rescue light  11  resembles a conventional flashlight on the outside. A user may energize laser light beam generator array  27  by closing electrical power switch  38  and sweeping the rescue light  11  across the horizon or in the direction of searching aircraft or ships so that the signaling light beam array produced can be spotted by searching individuals. The light beam pattern and distance spacing may be the same as the preferred embodiment above, being five or seven separate beams in a cluster with a line-generating lens. 
     Referring now to FIGS. 5 and 6, another embodiment of the laser beam array is shown having twelve separate laser light generators (L 1 -L 12 ) arranged to have each of their beams pass through right angle prisms  63 . Each laser light generator is a specific class laser (e.g. Class IIIa laser) disposed substantially in two linear lines adjacent to each other. This is illustrative that the laser light generators have thickness and therefore the projected laser light beams can not be brought into close alignment when the laser light sources are grouped together to form the array. The desired effect is to create a laser light beam pattern that in two dimensions extends far from the source, such as from the ground, vertically, while being quite thin horizontally for intensity purposes. 
     FIG. 7A shows the desired arrangement of the laser light generators as shown in FIGS. 5 and 6 where laser light beams are projected along essentially two vertical axes  64  and  66 . The twelve laser light beams  67  converge with twelve laser light beams  68  about eight miles out to double the intensity and make up for attenuation losses over the specified distance. The desired result is a taller and wider pattern being used to pass through a line generating lens or reflector (not shown) which produces a vertical sweep line which can extend from the horizon (ground or ocean surface) vertically several hundred feet. The final result of using an array as shown in FIGS. 5,  6  and  7 A, is to allow a taller and wider light pattern with more power to be elongated through a line generating lens or reflector producing for example a 100 foot vertical sweep line on the horizon with essentially 12 times the power than if one class IIIa laser was manipulated. Adding an additional twelve laser system to converge 8 miles away doubles that to twenty four times the power as shown in FIG.  7 A. However, government limitations on laser power is not exceeded. 
     FIGS. 7B and 7C show laser patterns (clusters) (five or seven laser sources) that can be altered for use, as in the preferred embodiment. 
     FIG. 8A shows how the results of FIGS. 5 and 6 can be used to create a signaling vertical line with increased visibility. This allows people in boats or aircraft to see the laser or light beams at great distances. FIG. 8A shows a scenario where two slightly converging separate multiple arrays  81  and  83  of laser light beams are mounted vertically in separate units as shown in FIGS. 5 and 6. The beams  81  and  83  are separated at distance X at the initial transmission point through cap  80 . The pair of line generating lenses  82   a  and  82   b  receive the light beams  81  and  83  and are spaced apart by amount less than “x”. The individual light beams spaced vertically  81  and  83  are then transmitted through space and are on a converging course such that at approximately eight miles away (or a desired distance to be set based upon the horizon or other variable), an observer will be at a point where the actual beam separation is zero. This means that of the multiple beams transmitted, all of the energy is now concentrated into a single thick line of light that is visible eight miles away, representing the sum total of each individual laser generator, each generator of which is at or below government safety levels as to the power permissible. 
     FIG. 8B shows two individual laser beam generator modules and rays and two line generating lenses for schematic representation to provide twice the intensity along the single line at a distance spaced away from the laser modules. Using the structure, and mounting the two laser modules in conjunction with line generating lenses in this manner, the advantage of using individual laser generator modules that are at or below the government safety levels can be combined in a way that safely allow for using the light intensity that is attenuated miles away from the laser modules and where intensity is inversely proportional to the length of the line generated. This will get the maximum benefit out of laser modules of a pre-determined power output. 
     Another alternate embodiment of the invention is shown in FIG.  9 A. In this embodiment, a small portable rectangular hand-held, water-proof, plastic housing  90  includes a strobe light mounted under a clear plastic lens  92  and at least one laser light generator  96 , that includes a line forming lens  98 . The dual acting power switch is shown at  94 . This embodiment has two modes of operation, one in which a strobe light  100  is illuminated that flashes for emergency purposes and a second mode where a laser light beam is generated that forms a vertical or single line that can be oriented vertically for search and rescue purposes as already described herein. Looking at FIGS. 9B and 9C, the device includes a pair of batteries  99  mounted inside a waterproof housing  91  and a strobe light  100  which is connected to the batteries through switch  94  as is the laser generator  96  and a line forming lens  98 . The switch  94  may have two positions, one for the strobe light and one for the laser light. Also, both laser and strobe lights could be illuminated at the same time, if necessary. The purpose of the invention shown in FIGS. 9A,  9 B and  9 C would be for search and rescue or survival to attract attention in order to be located, whether a person is in the ocean or on land. The laser beam is used for signaling in a vertical laser beam line that shows in FIG. 9A a target sweep where one would manually move the laser beam in a horizontal direction to sweep an area where one might find search and rescue crews. The strobe light is also useful for attracting attention from miles away. The operation of the strobe light  100  by itself is convention and does not form a part of the invention. 
     In alternate embodiments, different shaped lenses, mirrors and prisms can be employed that allow for the diversion, dispersion, addition or fanning out of laser light beams to create a desired end result approximately eight to ten miles or other desired distance from the light source. Light beams could be caused to converge eight or more miles away at the theoretical horizon from someone in a small craft or small elevated boat to get more energy directionally positioned at the horizon, creating a pattern which is easier to spot by personnel that are looking for the light source. 
     With the preferred embodiment light patterns and the particular housings shown in the invention, the ultimate purpose is to create a more powerful laser illumination system without exceeding the government designated safe class of each laser used. This laser system allows one to be found from someone that is lost in a body of water, or on land, and to attract the attention of a search party either in boats or aircraft. The use of multiple laser arrays, which have increased effective intensity, especially in conjunction with the use of one or more lenses, mirrors, and reflective prisms, can greatly increase the coverage area while at the same time extending the time that the light is available because of the reduced power consumption for the amount of light energy obtained using the laser sources. This is enhanced when altering the source using lenses, mirrors, and prisms creating light patterns which can be seen at greater distances, increasing the probability of being found. 
     The instant invention has been shown and described herein in what is considered to be the most practical and preferred embodiment. It is recognized, however, that departures may be made therefrom within the scope of the invention and that obvious modifications will occur to a person skilled in the art.