Abstract:
A vehicle lighting system providing lighting for an instrument panel generating light having a wave length, such as white light, which does not interfere with night goggle vision systems. The system comprises a portable housing, a battery pack, and an plurality of cables extending outwardly from the housing to a plurality of light-emitting elements providing white light proximate each of the plurality of vehicle instruments.

Description:
This application claims benefit of provisional application 60/145,453 filed on Jul. 23, 1999. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates in general to illumination systems for use in vehicles for use with night vision systems. 
     BACKGROUND OF THE INVENTION 
     It has now become a common practice for law enforcement, military, and emergency response personnel to utilize night vision imaging systems (NVIS) including night vision goggles (NVG) to conduct night or low-light operations. Currently, night vision imaging systems include either goggles (which are “binocular” or “monocular”) which are worn by an operator, and which respond to visible and near-infrared light having wavelengths up to 930 nanometers. As is conventional, the night vision imaging systems typically generate a visible, phosphor-screen image from normally imperceptible radiation. 
     Typically, night vision imaging system goggles include one or two image intensifier tubes mounted to a head strap or a helmet. The image intensifier is a vacuum tube device similar to a miniature video camera and screen packaged together. Typically, the intensifier includes a photocathode receptor which receives visible light and infrared light energy and converts the visible light and infrared light energy into electrons, a microchannel plate which multiplies the number of electrons emitted by the photocathode (thus serving as an amplifying device), and a green phosphor screen which converts the electrons into a visible image. Currently, there are two types of intensifier tubes which are in widespread usage. The first type is a generation II intensifier tube, which utilizes a multialkali photocathode. The second type is a generation III intensifier tube which utilizes a more sensitive gallium arsenide photocathodes. Generation III intensifier tubes are more costly than generation II photocathode tubes, but have a longer use life. 
     While night vision imaging systems are very useful in law enforcement, military, and emergency response applications, they are not tolerant of high levels of visible light or infrared radiation. In other words, night vision imaging systems are best when employed in actual low light conditions. 
     When personnel are within a vehicle, such as, without limitation, aircraft, watercraft, or land-based vehicles, the night vision imaging systems may be useful for night operations; however, it is not uncommon for the interior space of the vehicle to include sources of visible light or infrared radiation which interfere with the operation of the night vision imaging system. High intensity visible light or high intensity infrared radiation, which is within the operating range of the night vision imaging system, impedes the effective utilization of the night vision imaging system, sometimes rendering such devices essentially useless. Consequently, illuminated displays and other sources of light which are necessary for low light operation of communication and control equipment must be neutralized in order to render night vision imaging system useful for low light operations conducted from within a vehicle. While the problem is present in all vehicles, including watercraft and land-based vehicles, it is especially acute for aircraft which are highly-instrumented devices. For example, fixed-wing aircraft or rotor-wing aircraft include a large array of gages, displays, LED devices, and the like, which emit visible light and infrared radiation which does interfere with the utilization of night vision imaging systems, such as night vision goggles. 
     Accordingly, in order to allow low light operations, a variety of prior art approaches have been developed for dealing with the interfering light sources within the cockpit or interior space of other vehicles such as ships, boats, and land-based vehicles. 
     The present invention is of generally applicability to all vehicles which may be utilized during low light operations which would benefit from the use of night vision imaging systems, and is not limited to fixed wing and rotor wing aircraft; however, for purposes of exposition only, the specification contained herein will discuss primarily fixed-wing and rotor-wing aircraft. The prior art approaches will now be discussed, with reference to fixed-wing and rotor-wing aircraft. 
     One approach of the prior art is to replace the dials, gages, light emitting diodes, and illuminated displays within an aircraft with comparable equipment which is illuminated within a wavelength range which would not interfere with the utilization of night vision imaging systems. One significant drawback with this prior art approach is the significant costs associated with such retrofitting operations. The costs are high because regulatory agencies such as the Federal Aviation Administration strictly require documentation of such modifications. An additional reason for the expense is that the replacement instruments have considerable costs associated with them. 
     A second approach of the prior art is to replace the lighting or illumination source within the instruments. This is also expensive, since it requires that the instruments, gages, and displays be individually removed and modified: Again, considerable costs are associated with the documentation required for such operations, as well as for purchase of the replacement lighting sources. 
     A third approach of the prior art is to install post, bezel, or flood lighting within the craft cockpit which is an alternative means of lighting the essential displays and gages. One significant advantage is that the post, bezel, or flood lighting systems are supplementary systems which do not replace the existing illumination systems within the craft. During low light operations, the lighting systems of the craft are switched from an “on” condition to an “off” condition (which is referred to as a “blackout”). The supplementary posts, bezel, or flood lighting systems are turned on and used as a sole source of illumination of the various gages, displays, meters, and the like, during the duration of the low light operations. The night vision imaging systems may be then utilized without any interference from the illumination sources associated with the cockpit instrument lighting systems. 
     When this approach is utilized minor/major changes to the aircraft wiring must be accommodated. This permits power to be directed to the external accessories in lieu of the original instrument. 
     SUMMARY OF THE INVENTION 
     It is one objective of the present invention to provide a vehicle lighting system which does not require rewiring of the instrument panel. 
     It is another objective of the present invention to provide a vehicle lighting system which provides lighting for an instrument panel which is in a wavelength range which does not overlap with the night goggle vision systems. 
     These and other objectives are achieved as is now described. The present invention is directed to a supplemental lighting system which may be utilized in a vehicle during night vision imaging operations, in order to illuminate a plurality of vehicle instruments. A portable housing is provided. A battery pack is located within the portable housing. A plurality of electrical cables extend outwardly from the portable housing. These electrical cables define a plurality of current paths and electrical communication with the battery pack. A plurality of light-emitting circuit elements (preferably light emitting diodes) are coupled to a plurality of current paths. Each light-emitting circuit element provides a spot light, when energized, which as a wavelength which does not interfere with night vision imaging operations. A plurality of mechanical coupling devices are provided which locate the spot light of each of the plurality of light-emitting circuit elements relative to a particular one of the plurality of vehicle instruments. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a pictorial representation of an exemplary prior art cockpit; 
     FIG. 2 is a pictorial representation of the lighting system of the present invention implemented in a rotor wing craft; 
     FIG. 3 is a pictorial representation of the implementation of the lighting system of the present invention in a fixed wing craft; 
     FIG. 4 is a pictorial representation of the components which make up the lighting system of the present invention; 
     FIGS. 5A through 5E are pictorial representations of a bracket utilized in the preferred embodiment of the lighting system of the present invention; 
     FIG. 6 is a graphical representation of the frequency relative responses of night vision imaging systems and human vision; 
     FIG. 7 is an electrical schematic of the preferred power circuit of the present invention; 
     FIG. 8 is a cross-section view of an LED lamp in accordance with the present invention 
     FIG. 9 is a plan view of a circuit board in accordance with the present invention; 
     FIG. 10 depicts the preferred circuit board (and components) of the present invention; 
     FIG. 11 is a graphical view of the frequency of light generated by the LED lamps utilized in accordance with the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     FIG. 1 is a pictorial representation of a cockpit of an aircraft. As is shown, a plurality of conventional lighted gages, dials, meters and instrument panels are provided, all of which are essential for proper flight operations. The lighting systems which are conventional in most cockpits operate in a wavelength range which could potentially interfere with night vision imaging systems. Accordingly, for the flight personnel to utilize night vision imaging systems, the instrument lights and control lights must be powered-off. Otherwise, the infrared associated with standard illumination of the cockpit would become overpowering and make the night vision imaging system useless or ineffective. 
     An aircraft cockpit contains a number of different lighting systems, such as incandescent lights, active matrix LCDs, LEDs, and CRTs. The present invention is useful for providing alternative lighting for incandescent lighting systems. 
     FIG. 2 is a pictorial representation of the illumination system of the present invention utilized in a rotor wing craft installation, while FIG. 3 is a pictorial representation of the utilization of the illumination system of the present invention in a fixed wing craft installation. 
     With reference now to FIG. 2, illumination system  9  includes a power module  11  which has conductors  15 ,  17 , extending therefrom. Each conductor separates into subconductors. For example, conductor  15  is made up of subconductors  21 ,  23 ,  25 , and  27 . Likewise, conductor  17  is made up of subconductors  29 ,  31 ,  33 . The subconductors extend from the main conductors  15 ,  17 . A number of light emitting diodes are energized by current pathways which extend between conductors  15 ,  17  and subconductors  21 ,  23 ,  25 ,  27 ,  29 ,  31 , and  33 . For example, light emitting diodes  35 ,  37 ,  39  are carried by subconductor  27 . For subconductor  33 , light emitting diodes  41 ,  43 ,  45  are provided. In accordance with the illumination system  9  of the present invention, each dial, gage, meter or instrument has its own individual lighting which is provided by a light emitting diode which is dedicated thereto. Each light emitting diode provides a spot light for a particular location on the cockpit. When the cockpit lighting system is “powered-off”  5  the diodes provide the sole source of lighting which is compatible with night vision imaging systems. 
     In the rotor wing craft installation of FIG. 2, conductor  15  powers nine independent LED lamps. Conductor  17  also powers nine independent LED lamps. 
     FIG. 3 is a representation of a typical fixed wing craft installation of the lighting system  9  of the present invention. As is shown, conductor  75  extends from power module  11 . For this application, conductor  75  includes subconductors  81 ,  83 ,  85 ,  87  and  89  are connected thereto, which support a total of ten independent light emitting diode lamps. Conductor  77  includes subconductors  91 ,  93 ,  95 ,  97 ,  99 ,  101 , and  103 , which support a total of thirteen light emitting diode lamps. It is important to note that the cable assembly are customizable to satisfy industrial cockpit layouts or designs. 
     FIG. 4 is a pictorial representation of power module  11 . As is shown, a removable top  113  is provided for releasably engaging rectangular housing  115 . These components are secured together utilizing thumb/countersink screws (not depicted in this view). Within housing  115  is a battery cradle  117  which is adapted to receive a plurality of batteries. In the preferred embodiment, three “D” size batteries may be utilized. As a secondary power source, “AA” size batteries are utilized. Two female jack connectors  121 ,  123  are provided to allow electrical connection with electrical jacks  125 ,  127 . An on/off switch  129  is provided which is accessible from the exterior of housing  115 . Additionally, a potentiometer indicator  131  is provided which provides a “battery low” signal. Other battery combinations are also compatible to the system. For example, nine volt or lithium batteries could be utilized with or in various other battery combinations. 
     FIGS. 5A through 5E is a pictorial representation of a bracket  201  which is utilized to secure LED lamp  213  in position relative to an instrument panel in a flight cockpit. A conductor  215  supplies electrical current to LED lamp  213 . Bracket  201  secures LED lamp  213  in a particular position relative to a particular instrument to which it is dedicated. As is shown, bracket  201  includes horizontal portion  205 , vertical portion  203 , and angled portion  207 . Horizontal portion  205  is adapted to be flush with the instrument panel itself As is shown in FIG. 5D, a slot  209  is provided which is adapted in size and shape to engage an LED lamp which is utilized in position relative to the instrument panel. Vertical portion  203  extends upward from horizontal portion  205 . Angled portion  207  is provided at a particular angle relative to vertical portion  203 , but may be reshaped by the pilot, crew, or installation personnel to a particular orientation relative to a particular instrument in the control panel. In other words, a portion  207  is flexible enough to be reshaped to allow light to be directed to a particular location within an instrument panel. FIG. 5B is a cross section view (with dimensions provided) of bracket  201 . These are preferred dimensions, and not meant to be limiting of the present invention. Portion  207  is depicted in plan view in FIG.  5 C. As is shown, a groove  209  is provided which is adapted in size and shape to receive the LED lamp portion. FIG. 5E is a pictorial representation of the screw in position relative to horizontal portion  205 . Bracket  201  is held in position by a screw, just like post lighting systems of the prior art. 
     FIG. 7 is an electrical schematic which depicts the preferred circuit within the portable housing, all in accordance with the preferred embodiment of the present invention. As is shown, the circuit includes battery pack  301  and battery pack  303 . Battery pack  301  is preferably the primary power supply, and it consists of three “D” cell batteries coupled together in an array. Power supply  303  is a back-up, or secondary, power supply, which preferably includes three “AA” batteries also coupled together in an array. Switch SW 1  is a three-way switch which is defined by sliding contact  305  and stationary contacts  307 ,  309 ,  311 . Sliding contact  305  is moved between the three positions. In one position, power supply  301  is in an “on” position. In the middle position, no power supply is on, therefore the circuit is “off.” In the other position, power supply  303  is in the “on” position. The power provided by the power supply  301  or power supply  303  is supplied to output jacks  313 ,  315 . As is shown, the output jacks  313 ,  315  allow for the connection to both the positive and negative terminals of the power supplies, depending upon which is switched in the circuit. 
     FIG. 8 is a cross section view of an LED lamp utilized in the preferred embodiment of the present invention. As is shown therein, electrical conductors  401 ,  403  serve to connect LED  409  into the electrical circuit defined by the power supply within the portable housing (all as is depicted in FIG.  7 ). As is shown, LED  409  is contained within relatively small housing  405 . The back end of the housing is sealed with an epoxy light barrier  407 . The front end of the housing is covered by epoxy light barrier  411  which transmits the light generated by light emitting diode  409 . 
     FIG. 9 is a plan view of a circuit board onto which the LED  409  and other components are connected. As is shown, circuit board  609  is adapted with a plurality of circuit contacts. As is shown resistor  601  is coupled between two of the contact points. Cable  603  provides an electrical circuit connection to the power supply circuit (of FIG.  7 ). Conductors  605 ,  607  are banded together within conductor  603 , and are depicted in FIG. 9 as making electrical connection with particular portions of circuit board  609 . 
     FIG. 10 is a side view of circuit board  609 . As is shown, LED  409  is connected to circuit board  609 . In the preferred embodiment of the present invention, LED  409  comprises a model no. 2145-105, a light emitting diode manufactured by Pynco Inc., which preferably provides illumination in the range as defined by FIG.  11 . 
     FIG. 6 is a graphical representation of the relative responses of particular night vision goggles, as well as the typical responsiveness of a human eye. As is shown, the light response for generation II and generation III night vision goggles is depicted graphically. Also, as is shown, the human photopic curve is also depicted graphically. As is shown, there is very little overlap between the photopic curve and generation III night vision imaging systems. Accordingly, in accordance with the preferred embodiment of the present invention, the light emitting diode provides illumination in a range which does not interfere with night vision goggle systems, and thus which can be utilized safely. A comparison of FIGS. 6 and 11 reveals that the LED light sources provide light outside the frequency range of operation of GEN III Night Vision goggles. The white light provided by the LED light sources is a particularly good lighting for human vision, so cockpit vision is not limited or impaired (such as is possible with green light which impairs the perception of colors) when the goggles are not utilized, and there is no interference with the night vision goggles.