Patent Publication Number: US-9851066-B2

Title: Reflector signal lamp having a hidden light source

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the benefit of Czech Republic Patent Application No. PV 2011-372 filed Jun. 23, 2011, the entire disclosure of which is hereby incorporated herein by reference. 
     FIELD OF THE INVENTION 
     This invention pertains to a reflector signal lamp with a hidden light source, and more particularly to a reflector signal lamp with a hidden light source for a front and rear signal lighting of motor vehicles. 
     BACKGROUND OF THE INVENTION 
     Presently, signal lamps are used for front and rear running lights, brake lights, turn indicator lights, backup lights or fog lights in external automobile lighting. An optical system of the signal lamp, typically, includes a light source, a reflector, one or more optical filters, and an exterior lens. 
     The light sources used are bright incandescent light bulbs or light emitting diodes (LEDs). 
     Typically, there are two types of optical systems: direct and indirect. 
     A direct optical system has a visible light source situated approximately in a middle of a reflector. A direction of reflected light is in a direction of an axis of the light source. 
     On the other hand, indirect optical system has a visible light source situated at a side of a reflector, while a direction of reflected light is approximately perpendicular to an axis of the light source. 
     A certain portion of light emitted by the light source cannot be effectively reflected and is lost as direct light, thereby decreasing an efficiency of the optical system. Further, the light source can be easily recognized as a relatively bright object against a darker background of a reflecting surface of the reflector. 
     It would be desirable to produce a signal lamp having a hidden light source, wherein the light source is not visible from any direction, while a light emitting surface of the reflector is sufficiently visible. 
     SUMMARY OF THE INVENTION 
     In concordance and agreement with the present invention, a signal lamp having a hidden light source, wherein the light source is not visible from any direction, while a light emitting surface of the reflector is sufficiently visible, has been surprisingly invented. 
     In one embodiment, a signal lamp for a vehicle, comprises: at least one hidden light source for emitting light; a reflector for reflecting the light emitted by the at least one light source away from the vehicle; and at least one light guide disposed between the reflector and a cover of the signal lamp to direct the light emitted by the at least one light source onto the reflector. 
     In another embodiment, a signal lamp, comprises: at least one hidden light source for emitting light; a reflector for reflecting the light emitted by the at least one light source; and at least one light guide disposed between the reflector and a cover of the signal lamp to direct the light emitted by the at least one light source onto the reflector, the at least one light guide having a first end and a second end, wherein the first end is disposed adjacent the at least one light source and the second end is located adjacent a focus point of the reflector. 
     In yet another embodiment, a signal lamp, comprises: at least one light source for emitting light, wherein the at least one light source is hidden from view by a frame of the signal lamp; a reflector for reflecting the light emitted by the at least one light source, wherein the reflector includes at least one parabolic surface; and at least one light guide disposed between the reflector and a cover of the signal lamp to direct the light emitted by the at least one light source onto the reflector. 
     The essence of the invention being that at least one light source is arranged at an outer peripheral edge of a reflector behind a frame, which peripheral shape corresponds to a shape of the outer peripheral edge of the reflector, and which is made of nontransparent material, while a light guide has an exit end located at a focus point of the reflector. Moreover, the exit end of the light guide is configured as a light scattering component. The light guide also has an entry end configured as a collimation component. 
     Furthermore, the at least one light source of the signal lamp is an incandescent bulb or LED, and the LED is located on a rigid board provided with printed circuits. A number of the light sources corresponds to a number of light guide branches. The reflector includes a partly or fully light-reflecting surface. The reflector also includes one or more parabolic surfaces, which can be provided with light scattering elements. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above, as well as other advantages of the present invention, will become readily apparent to those skilled in the art from the following detailed description of the preferred embodiment when considered in the light of the accompanying drawings in which: 
         FIG. 1  is a schematic cross-sectional view of a signal lamp according to embodiment of the inventions, wherein the signal lamp has one hidden light source; 
         FIG. 2  is a schematic cross-sectional view of a signal lamp according to another embodiment of the invention, wherein the signal lamp has two hidden light sources; 
         FIG. 3A  is a front elevational view of the signal lamp illustrated in  FIG. 1 ; 
         FIG. 3B  is a front elevational view of a signal lamp according to another embodiment of the invention, wherein the signal lamp has three hidden light sources; and 
         FIG. 3C  is a front elevational view of a signal lamp according to another embodiment of the invention, wherein the signal lamp has six hidden light sources. 
     
    
    
     DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS OF THE INVENTION 
     The following detailed description and appended drawings describe and illustrate various embodiments of the invention. The description and drawings serve to enable one skilled in the art to make and use the invention, and are not intended to limit the scope of the invention in any manner. 
       FIG. 1  illustrates a signal lamp including an optical system according to an embodiment of the invention. The optical system includes a light source  1 , a light guide  2 , a frame  5 , a reflector  3 , and a cover  4 . It is understood that the cover  4  can be formed from any suitable material such as a glass material, for example. Light emitted by the light source  1  is collimated and directed by the light guide  2  to the reflector  3 , where the light is reflected on a first surface  31  and directed through the cover  4 . 
     In certain embodiments, the light source  1  is a bright incandescent light bulb of the reflector  3  or light emitting diode (LED), which is placed around an edge of the signal lamp behind a frame  5 , for example. As shown in  FIG. 2 , additional light sources  1  and light guides  2  can be employed if desired. For example, a single light source  1  is used in  FIG. 3A , three light sources  1  are used in  FIG. 3B , and six light sources are used in  FIG. 3C . It is understood that the frame  5  can be made of any suitable material such as a nontransparent material. 
     An entry end  21  of the light guide  2  is configured as a collimation component  23 . The collimation component  23  can be an optical collimator or a Fresnel lens which produces a collimated beam of light for a propagation of light in the light guide  2  without losses, for example. 
     An exit end  22  of the light guide  2 , situated near a focus point F of the reflector  3 , is configured as a light scattering component  24 . The light scattering component  24  includes optical grooves, prisms, or other optical elements used to produce an evenly scattered light beam from the light guide  2  to the first surface  31  of the reflector  3  to increase a size of an light emitting surface. 
     The light guide  2  includes a plurality of branches  6 . A number of the branches  6  is based upon a number of the light sources  1 . It is understood that the light sources  1  can be LEDs placed on a rigid board with printed circuits in a single plane, as shown in  FIG. 2 . 
     As illustrated in  FIG. 1 , the first surface  31  of the reflector  3  is provided with a partly or fully reflective coating. The first surface  31  of the reflector  3  may be configured as a single parabolic surface or several parabolic surfaces having light scattering elements  32  formed therein. The light scattering elements  32  can improve a homogeneity of illumination of an illuminated surface of the reflector  3  and an overall visibility. 
     A size of the reflector  3  of the signal lamp depends on a type of signal function being provided. The signal lamps shown in  FIGS. 1-3C  produce sufficient light and a light scattering for a reflector  3  with the associated light guide  2 . 
     When the LEDs are used as the light source  1 , or light sources  1 , in combination with a properly arranged light guide  2 , and a main portion of the light emitted by the light source  1 , or light sources  1 , is properly utilized. Therefore, light losses for the light source  1 , or light sources  1 , are minimized. The signal lamp according to the invention is more efficient than signal lamps of the prior art. 
     Further, the reflector signal lamp with the hidden light source  1  in an on and off state is distinguishable from the signal lamps of the prior art. 
     The signal lamp having a hidden light source  1  has been developed to meet requirements of light division, light color and optimal composition of the light emitting surfaces, while maintaining safe signal registration.