Abstract:
A blood tracking system, comprising a light source comprising a first LED configured to emit light of a first color and a second LED configured to emit light of a second color is disclosed. The light of the first color and the light of the second color are mixed to appear as light of a third color when the first LED and the second LED are activated; and wherein the light of a third color is effective for highlighting blood. A method of highlighting a red material comprising illuminating the red material with both red and blue light is also disclosed.

Description:
CROSS-REFERENCE TO RELATED PATENT APPLICATIONS  
       [0001]     This application claims the benefit of U.S. Provisional Application No. 60/598,289, filed Aug. 3, 2004, entitled “Blood Tracking System,” which is incorporated herein by reference in its entirety. 
     
    
     BACKGROUND  
       [0002]     The present invention relates generally to the field of blood tracking. In particular, the present invention relates to a portable lighting unit configured to track blood using a light emitting diode (LED) illumination system.  
         [0003]     There are occasions in which it is useful to be able to easily identify small amounts of blood in a particular environment. For example, a hunter may wound an animal, such as a deer, that runs some distance away from the hunter after being wounded. In such a case, the hunter would like to follow the blood trail in order to find the animal. Small drops of blood can be difficult to see on the ground and on foliage, especially in low light conditions. To aid the hunter, blood tracking systems have been devised that help differentiate the red color of the blood from the rest of the environment. Such systems include the utilization of special filters placed on flashlights and/or special goggles or glasses that highlight the blood.  
         [0004]     It would be advantageous to provide a portable lighting device that gives the user true blood tracking capability in low-level lighting conditions by using the optical principle of color enhancement. In particular, it would be advantageous to provide a lighting device that gives a distinct visual appearance to blood without requiring special filters on a light source or requiring the user to wear special glasses or goggles.  
       SUMMARY OF THE INVENTION  
       [0005]     One embodiment of the invention relates to a blood tracking system, comprising a light source comprising a first LED configured to emit light of a first color and a second LED configured to emit light of a second color. The light of the first color and the light of the second color are mixed to appear as light of a third color when the first LED and the second LED are activated; and wherein the light of a third color is effective for highlighting blood.  
         [0006]     Another embodiment of the invention relates to a flashlight for detecting and tracking red objects comprising a housing, a red LED coupled to the housing, a blue LED coupled to the housing, a power source, and an actuator for activating the red LED and the blue LED. The light emitted by the red LED and the light emitted by the blue LED mix to create a magenta spot that is suitable for highlighting red material.  
         [0007]     Yet another embodiment of the invention relates to a method of highlighting a red material comprising illuminating the red material with both red and blue light. The red and blue light mix to produce a magenta spot, which when illuminating a red colored material, makes the red material appear orange to the human eye. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0008]      FIG. 1  is a front elevation view of a tracking device.  
         [0009]      FIG. 2  is a side elevation view of a tracking device.  
         [0010]      FIG. 3  is a perspective view of a tracking device.  
         [0011]      FIG. 4  is an elevation view of an LED array.  
         [0012]      FIG. 5  is an elevation view of an LED array.  
         [0013]      FIG. 6  is an elevation view of an LED array.  
         [0014]      FIG. 7  is an elevation view of an LED array.  
         [0015]      FIG. 8  is an elevation view of an LED array.  
         [0016]      FIG. 9  is an elevation view of an LED array.  
         [0017]      FIG. 10  is an elevation view of an LED array.  
         [0018]      FIG. 11  is an elevation view of an LED array.  
     
    
     DETAILED DESCRIPTION  
       [0019]     Color perception cannot be attributed directly and solely to wavelengths of light. The eye focuses slightly differently on long wavelengths (reds) than on short wavelengths (blues). According to an exemplary embodiment of the present invention, a tracking device may include a multiple color light source having a red LED light beam and a blue LED light beam that create an illusion causing the eye to see red objects in low level lighting conditions as blaze orange. Simultaneously illuminating a red blood spot with the red LED beam and the blue LED beam of the system creates the desired highlighted orange blood effect. The highlighted blood appears orange and the surrounding background green or brown flora appears blue/purple under the multi color LED beam even when the flora is wet.  
         [0020]     In an exemplary embodiment, the blood tracking system is incorporated into a portable light source, such as a headlamp flashlight. The headlamp may have a removable, adjustable headband. The headlamp may utilize a single AAA battery to provide power to the LEDs. Alternatively, multiple batteries may be used and the batteries may be of various sizes and types. The blood tracking system may be utilized in other portable light sources such as handheld flashlights and lanterns.  
         [0021]     One headlamp into which the system may be incorporated is a TRACER headlamp, sold by Gerber Legendary Blades, a Fiskars Brands Company. The TRACER headlamp circuitry may be modified to incorporate a red and a blue LED. Trimming resistors, which may be adjusted to provide a desired resistance, may be added to allow for varying the intensity of each LED in order to generate a desired output.  
         [0022]     In some embodiments, two distinct colors may be utilized. In an exemplary embodiment, one or more blue LEDs (i.e. LEDs having a peak wavelength centered in the range of about 410 nm to about 500 nm) may be used with one or more red LEDs (i.e. LEDs having a peak wavelength in the range of about 600 nm to about 740 nm) to produce a spot that appears to be magenta to a user. In some embodiments, an LED having an output centered at about 425 nm may be used with an a LED having an output centered at about 625 nm. In another exemplary embodiment, a red LED having a wavelength centered around 628 nm and a blue LED having a wavelength centered around 470 nm may be used.  
         [0023]     In some embodiments, the blood tracking system may include two LEDs (a red LED and a blue LED) that are simultaneously activated to provide the desired blood tracking effect. In other embodiments, additional LEDs are used to increase the brightness of the light source, such as two red LEDs and two blue LEDs, or even more LEDs, such as 3-6 red LEDs and 3-6 blue LEDs. The number of red LEDs may be greater or less than the number of blue LEDs. Also, the intensity of the red LEDs may be greater of less than that of the blue LEDs.  
         [0024]     In another embodiment, the red LED may be pulsed at a particular frequency, which, when combined with the steady output of the blue LED, can enhance the visual signature of the blood or other red material being tracked.  
         [0025]     In some embodiments, the LEDs may be used individually, to provide either red output or blue output separately. In other embodiments, other LEDs may be added to the system, including other LEDs having different colors or wavelengths, such as infrared wavelengths. Circuitry may be utilized to provide different lighting options of the various LEDs and combinations of LEDs.  
         [0026]     The tracking device has several potential uses in addition to use in the hunting context described above. For example, the system may have several potential military uses, such as by medics to determine the source of blood on a body that is covered by dirt, mud, or other material obscuring the wound providing the source of blood. Further, special forces personnel may utilize the invention to track enemy combatants that may have been wounded and are providing a blood trail. Also, the tracking device may be used by forensic analysts to find blood.  
         [0027]     Referring to  FIGS. 1-3 , according to an exemplary embodiment, tracking device  10  includes a housing with a handle  12 , and a head  14 . Handle  12  includes a grip portion  16 , first power switch  18 , a power supply  20 , and a second power switch  22 . Head  14  and handle  12  are shown coupled to each other at an angle of about 90° and may be formed as a single unitary body. Alternatively, head  14  and handle  12  may be coupled at other angles or in-line such that the head and handle extend along either the same longitudinal axis, or along longitudinal axes that are substantially parallel. In yet another embodiment, head  14  may be rotatably coupled to handle  12  to allow a user to adjust the angle formed by head  14  and handle  12 .  
         [0028]     Handle  12  may include a grip portion  16  that includes grooves  24  for the fingers of a user to contact while using tracking device  10 . Handle  12  is shown as being generally straight along a longitudinal axis. Alternatively, other ergonomic configurations including a curved handle may be used. Power supply  20  or handle  12  may include a removable cover  26  which may cover a battery compartment. According to some embodiments, tracking device  10  may be adaptable to be used with alternating or direct current from an external power source.  
         [0029]     Head  14  may include a primary light source  30  and a secondary light source  32 . Primary light source  30  may include a lamp  34 , a reflector  36 , cap  38 , and lens  40 . Lamp  34  may be a xenon bulb. Alternatively, lamp  34  may be another type of incandescent bulb, or one or more white LEDs. Reflector  36  may be generally parabolic in shape to direct light emitted from lamp  34  into a beam. Reflector  36  may be faceted or smooth. Primary light source  30  may include a cap  38  for securing the primary light source  30  to head  14 . Cap  38  may be threadably or otherwise coupled to head  14 . Lens  40  may be disposed within cap  38  to provide a water resistant seal for primary light source  30 . According to some embodiments, reflector  36  may be coupled to cap  38  such that rotation of cap  38  moves reflector  36  relative to lamp  34  whereby the width of the light beam produced by primary light source  30  may be adjusted by rotating cap  38 . Second power switch  22  may be used to turn primary light source  30  on and off.  
         [0030]     Secondary light source  32  may include an LED array  42 , shown as eight LEDs of similar size in  FIG. 1 . A greater or lesser number of LEDs in other configurations may also be used. LED array  42  may be controlled by first power switch  18 . In some embodiments, first power switch  18  may simultaneously deactivate primary light source  30  and activate LED array  42 .  
         [0031]     In some embodiments, tracking device  10  may optionally include a power indicator  44 , shown as three LEDs, that may be used to indicate the strength of batteries used to power tracking device  10 . Alternatively, a greater or lesser number of LEDs in other configurations may also be used to indicate battery strength. Also, power indicator  44  may be placed in a variety of positions on tracking device  10 . Secondary light source  32  may be covered by lens  46  to protect LED array  42  and power indicator  44 .  
         [0032]     According to some embodiments, removable cover  26  may include an optional coupling point  28  which may be used to attach a lanyard to tracking device  10 . Alternatively, a coupling point for a lanyard may be provided elsewhere on tracking device  10 .  
         [0033]     Referring to  FIG. 4 , LED array  42  may include a total of eight LEDs  48  and  50 . According to some embodiments, LEDs  48  may be blue while LEDs  50  are red. Alternatively, LEDs  48  may be red while LEDs  50  are blue.  
         [0034]     Referring to  FIG. 5 , an LED array for use in a tracking device may include a total of six LEDs. According to some embodiments, LEDs  52  may be blue while LEDs  54  are red. Alternatively, LEDs  52  may be red while LEDs  54  are blue.  
         [0035]     Referring to  FIG. 6 , an LED array for use in a tracking device may include LED dies (i.e. components made of a semiconductor material used to generate light in an LED). According to some embodiments one or more red LED dies  56  may be used with one or more blue LED dies  58 . The LED dies may be focused and tuned to produce a homogenous magenta spot.  
         [0036]     Referring to  FIG. 7 , an LED array for use in a tracking device may alternatively include one or more red LED dies  60  may be used with one or more blue LED dies  62  and one or more green LED dies  64  where the green output is kept to a low level relative to the red and blue outputs to avoid diminishing the highlighting effect of the tracking device.  
         [0037]     Referring to  FIG. 8 , an LED array for use in a tracking device may include a bicolor LED  66 . According to some embodiments one or more red emitter outputs  68  may be used with one or more blue emitter outputs  70 . The LED emitter outputs may be focused and tuned to produce a homogenous magenta spot.  
         [0038]     Referring to  FIG. 9 , an LED array for use in a tracking device may include a tricolor LED  72 . According to some embodiments, the tricolor LED  72  may include one or more red emitter outputs  74 , one or more blue emitter outputs  76 , and one or more green emitter outputs  78 . The LED emitter outputs may be focused and tuned to produce a homogenous magenta spot.  
         [0039]     Referring to  FIG. 10 , an LED array for use in a tracking device may include a magenta LED  80 . The magenta LED  80  may include an emitter  82  designed to emit a magenta output (i.e. a combination of blue and red wavelengths).  
         [0040]     Referring to  FIG. 11 , a white LED  84  may be used with a filter  86 . Filter  86  may absorb green light while transmitting and balancing blue and red light to create a magenta beam. Alternatively, a plurality of filters may be used create a magenta beam. In some embodiments, a plurality of light sources, such as white LEDs may be used with filters to create a magenta beam. For example, one light source including one or more white LEDs and a blue filter may be used with a second light source including one or more white LEDs and a red filter.  
         [0041]     While the detailed drawings and specific examples given describe various exemplary embodiments of the blood tracking system, they serve the purpose of illustration only. It is to be understood that the invention is not limited in its application to the details of construction and the arrangements of components set forth in the preceding description or illustrated in the drawings. For example, other arrangements of LEDs may be used to create the desired blood tracking effect, or the flashlight may be one of a variety of configurations known in the art. Furthermore, other substitutions, modifications, changes, and omissions may be made in the design, operating conditions, and arrangements of the exemplary embodiments without departing from the scope of the invention as expressed in the appended claims.