Abstract:
A vehicle-mounted warning light system comprises a housing containing a central light surrounded by several sets of outer lights. A controller is programmed to light the central first, and then each set of outer lights in sequence, while at the same time increasing the intensity of the lights, so that the system appears to an observer to be a single light that is getting bigger and brighter. This creates the illusion that the vehicle is travelling toward the observer faster than it actually is, thus prompting the observer to quickly yield right-of-way.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a continuation of U.S. patent application Ser. No. 13/092,934, filed Apr. 23, 2011, the entire contents of which are herein incorporated by reference. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    This invention relates to the field of lighting systems. 
         [0004]    More particularly, the invention relates to a warning light system for emergency vehicles. 
         [0005]    In a further and more specific aspect, the invention concerns a warning light system for creating the illusion that an emergency vehicle is travelling at a speed higher than its actual velocity. 
         [0006]    2. Description of the Prior Art 
         [0007]    Emergency vehicles such as fire trucks, ambulances, and police cars are typically fitted with warning light systems for alerting other motorists that they must yield the right-of-way. These systems may comprise steadily burning lights, flashing lights, rotating lights, LEDs, or strobe lights. They are available in various forms such as single beacons and elongated light bars, and can be integral with or secured to the rooftop, grille, or other location on the exterior of the vehicle. Regardless of the type of lighting system used, however, there are always drivers who fail to move quickly out of the way because they underestimate the speed at which the emergency vehicle is travelling. Under the best of circumstances, this will slow down the emergency vehicle; under the worst, it can cause a serious traffic accident. 
         [0008]    Accordingly, it is an object of the present invention to provide a warning light system for emergency vehicles that, when activated, conveys a greater sense of urgency to surrounding motorists, pedestrians, and onlookers, prompting them to yield immediate right of way. 
       SUMMARY OF THE INVENTION 
       [0009]    The present invention achieves its objectives by taking advantage of the way the human eye and brain perceive motion. In general, objects appear to get larger and brighter as they approach an observer. An object that is travelling quickly appears to increase in size and brightness at a faster rate than an object that it is travelling slowly. By the same logic, if an object appears to be getting larger and brighter, the observer&#39;s brain perceives the object as getting closer even if it is actually stationary, or if the object is approaching, the observer&#39;s brain perceives it as travelling faster than it really is. Accordingly, the lighting system of the present invention comprises at least one light source and control means for varying the apparent size and brightness of the light source such that the light source appears to be travelling toward or away from an observer at a rate faster than the light source is actually travelling. 
         [0010]    In a further and more specific embodiment of the invention, the lighting system comprises a plurality of lights, including at least one central light and at least one set of outer lights adjacent to the central light. The control means comprises a controller programmed to initially illuminate only the central light, and then to illuminate the outer lights so that the apparent size and brightness of the light source increase over time, giving the observer the impression that the light source is approaching more quickly than it actually is. 
         [0011]    In one embodiment of the invention, the central and outer lights are collinear so they may be mounted on the vehicle in the form of a light bar. In another embodiment, the outer lights are arranged in concentric circles around the central light. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]    The foregoing and more specific objects and advantages of the instant invention will become readily apparent to those skilled in the art from the following detailed description of the preferred embodiments thereof taken in conjunction with the drawings in which: 
           [0013]      FIGS. 1A-E  are schematic drawings of a lighting system according to a first embodiment of the invention, wherein the lights are arranged in a straight line; 
           [0014]      FIGS. 2A-E  are schematic drawings of a lighting system according to a second embodiment of the invention, wherein the lights are arranged in concentric rings; 
           [0015]      FIGS. 3A-D  are graphs showing how the brightness of each set of lights within in a system varies over time and 
           [0016]      FIG. 3E  is a graph showing how the brightness of the entire system varies over time. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0017]    Turning now to the drawings in which like reference characters refer to corresponding elements throughout both views, attention is first directed to  FIG. 1A , which shows a lighting system according to the a first embodiment of the invention, indicated in its entirety by the numeral  10 . The lighting system  10  comprises a rectangular housing  12  containing a central light  14 , a first pair of lights  16   a,b  arranged on opposite sides of the central light  14 , a second pair of lights  18   a,b  arranged on opposite sides of the first pair of lights  16   a, b,  and a third pair of lights  20   a,b  arranged on opposite sides of the second pair of lights  18   a,b . Although or illustrative purposes, the lights  14 - 20 , which may be incandescent or LED, flashing or solid, white or colored, are shown to be spaced apart; they should be close enough together so that when all the lights are lit, they will appear to the viewer to be a single elongated light, rather than a number of individual lights. 
         [0018]    Initially, all of the lights  14 - 20  are turned off, as indicated by the dark shading in  FIG. 1A , but at time t 1  the central light  14  turns on, as shown in  FIG. 1B . The central light  14  is initially dim and may be constant, as shown by segment A in  FIG. 3A , but at time t 2 , its brightness I 1  begins to increase, as shown by segment B. Simultaneously, the first pair of lights  16   a, b , turns on, as shown in  FIG. 1C , and also begins to gradually increase in brightness I 2 , as shown by segment B′ in  FIG. 3B . At time t 3 , the second pair of lights  18   a, b , turns on, as shown in  FIG. 1D , and increases in brightness I 3 , as shown by segment C in  FIG. 3C . At time t 4 , the third pair of lights  20   a,b  turns on, as shown in  FIG. 1E , and increases in brightness I 4 , as shown by segment D in  FIG. 3D . Finally, at time t 5 , all the lights are turned off, and remain off until time t 6 , when the whole process repeats itself. 
         [0019]      FIG. 3E  shows the total brightness I 5  of the light system  10  increasing over time. From time t 1  to time t 2 , the total brightness I 5  is equal to the brightness I 1  of central light  14 . From time t 2  to time t 3 , the total brightness I 5  is equal to the brightness I 1  of the the central light  14  plus the brightness I 2  of the first light pair  14   a, b . From time t 3  to time t 4 , the total brightness I 5  is equal to the brightness I 1  of the the central plus the brightness I 2  of the first light pair  14   a,b  and the brightness I 3  of the second light pair  16   a, b . From time t 4 to time t 5 , the total brightness I 5  sum of the brightness I 1 +I 2 +I 3 +I 4  of all of the lights individually. 
         [0020]    To a an observer viewing from a distance, this does not appear as a number of lights being lit in sequence, but as a single light that is getting bigger and brighter over time, which creates the illusion that the lighting system (and therefore the vehicle on which it is mounted) is travelling towards the observer at a speed faster than it actually is. Conversely, the sequence could be reversed, with all the lights initially lit at full intensity and progressively being turned off toward the center while the brightness is also being reduced, to create the perception of faster movement away from the observer. 
         [0021]      FIGS. 2A-E  show a lighting system  110  according to a second embodiment of the invention, wherein the lights are arranged in a circular configuration. In this embodiment, the system comprises a circular housing  112  containing a central light  114 , a first light ring  116  which surrounds the central light  114 , a second light ring  118  which surrounds the first ring of lights  116 , and a third light ring  20  which surrounds the second light ring  118 . 
         [0022]    As in the first embodiment, all the lights are originally turned off, as shown in  FIG. 2A . At a predetermined time, the center light  114   a  turns on, as shown in  FIG. 2B , followed by the first light ring  116  as shown in  FIG. 2C , and then the light ring  118  as shown in  FIG. 2D , followed by the third light ring  120  as shown in  FIG. 2E . Finally, the entire system of lights then turns off, returning to the state shown in  FIG. 2A , where the sequence repeats itself Each light ring may consist of either a plurality of individual lights arranged in a circle, or a single annular light. 
         [0023]    The foregoing two embodiments are intended as examples only, and are not intended to limit the invention in terms of the shape of the lighting system, number or spacing of lights, or the rate of change of intensity of illumination. For example, the lights need not become brighter at a linear rate as shown in  FIGS. 3A-E , but can be programmed to intensify or dim in any fashion that effectively gives the impression of rapid movement toward (or away from) the observer. This can easily be determined by experimentation. 
         [0024]    Various other modifications and variations to the embodiment herein chosen for purposes of illustration will readily occur to those skilled in the art. To the extent that such variations and modifications do not depart from the spirit of the invention, they are intended to be included within the scope thereof which is assessed only by a fair interpretation of the following claims.