Abstract:
A high-contrast miniature headlamp includes at least one light-emitting element, a first reflective surface, and a second reflective surface. The high-contrast miniature headlamp forms a virtual equivalent light source of the light-emitting element via the first reflective surface to increase the equivalent distance between the light source and the second reflective surface, thereby enhancing the contrast of the cutoff line of the beam pattern produced by the headlamp. The headlamp is so configured that, under the condition of maintaining its miniature design and reducing cost without compromising optical efficiency, a beam pattern with a high-contrast cutoff line (i.e., a high-contrast beam pattern) can be generated to significantly improve the safety provided by automobile lighting.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Technical Field 
         [0002]    The present invention relates to a high-contrast miniature headlamp and, more particularly, to a high-contrast miniature headlamp which can reflect the light of the light source for a second time to increase the length of the optical path, thereby producing a clear cutoff line between the illuminated area and the non-illuminated area. 
         [0003]    2. Description of Related Art 
         [0004]    With the modernization of society, our demands for transportation means, such as cars, are increasing, and more and more importance is attached to car lamps as their functions are directly linked to the personal safety of car drivers and other road users. 
         [0005]    Recently, therefore, improvements and innovative inventions on car lamps or car lamp structures that are intended for better beam patterns are drawing much attention. The mainstream technique, however, still lies in lens improvement, which increases the contrast of a beam pattern only slightly and is disadvantaged by low optical efficiency and bulkiness in design. 
         [0006]    Another well-known technique is to increase the area used for reflecting the light of the light source. While this approach can enhance optical efficiency to some degree, a car lamp thus designed cannot generate a clear cutoff line without occupying a large volume, which increases the cost of implementation and reduces the willingness of use. 
         [0007]    In view of the above, it has been the hope of car users and the car industry alike to sec the creation of a practical, high-contrast miniature headlamp whose optical design enables a clear cutoff line to be formed not only despite the small volume of the lamp, but also without lowering optical efficiency, so as to significantly increase the safety provided by automobile lighting. 
       BRIEF SUMMARY OF THE INVENTION 
       [0008]    The present invention discloses a high-contrast miniature headlamp including at least one light-emitting element, a first reflective surface, and a second reflective surface. By implementing the present invention, a headlamp can produce a clear cutoff line between the illuminated area and the non-illuminated area (i.e., a high-contrast beam pattern) without having to increase the physical volume of the lamp while featuring cost reduction but no reduction in optical efficiency. The goal is to significantly increase the safety provided by automobile lighting. 
         [0009]    According to one aspect of the present invention, a high-contrast miniature headlamp includes at least one light-emitting element, a first reflective surface, and a second reflective surface. The light-emitting element is provided on one side of the first reflective surface so that the first reflective surface can reflect the light projected thereon by the light-emitting element while the light-emitting element forms a virtual equivalent light source on the other side of the first reflective surface. The second reflective surface is fixedly provided adjacent to the light-emitting element but is not directly exposed to the light projected by the light-emitting element. The second reflective surface reflects the light of the light-emitting element that is reflected by the first reflective surface, and light reflected from the second reflective surface propagates outward through an outgoing surface. 
         [0010]    According to another aspect of the present invention, a high-contrast miniature headlamp includes at least one light-emitting element and a light-permeable member fixedly provided adjacent to, and directly exposed to the light projected by, the light-emitting element. The light-permeable member includes a first reflective surface and a second reflective surface. The light-emitting element is provided on one side of the first reflective surface in order for the first reflective surface to reflect the light projected thereon by the light-emitting element, and for the light-emitting element to form a virtual equivalent light source on the other side of the first reflective surface. The second reflective surface is fixedly provided adjacent to, but is not directly exposed to the light projected by, the light-emitting element. The second reflective surface reflects the light of the light-emitting element that is reflected by the first reflective surface, and light reflected from the second reflective surface propagates outward through an outgoing surface. 
         [0011]    Implementation of the present invention at least provides the following advantageous effects; 
         [0012]    1. The costs of headlamps can be lowered while the miniature headlamp design is retained. In addition, the lighting functions of headlamps can be enhanced without compromising optical efficiency. 
         [0013]    2. The same headlamp structure can produce a high beam and a low beam, and the length of the optical path is increased by secondary reflection. 
         [0014]    3. A headlamp can output a beam pattern with a clear cutoff line between the illuminated area and the non-illuminated area to substantially increase the safety provided by automobile lighting. 
         [0015]    The features and advantages of the present invention are detailed hereinafter with reference to the preferred embodiments. The detailed description is intended to enable a person skilled in the art to gain insight into the technical contents disclosed herein and implement the present invention accordingly. In particular, a person skilled in the art can easily understand the objects and advantages of the present invention by referring to the disclosure of the specification, the claims, and the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         [0016]    The invention as well as a preferred mode of use, further objectives and advantages thereof will be best understood by reference to the following detailed description of illustrative embodiments when read in conjunction with the accompanying drawings, wherein: 
           [0017]      FIG. 1  is a schematic sectional view of the high-contrast miniature headlamp in an embodiment of the present invention; 
           [0018]      FIG. 2  schematically shows how light travels in the high-contrast miniature headlamp in an embodiment of the present invention; 
           [0019]      FIG. 3  is a schematic sectional view showing the high-contrast miniature headlamp of  FIG. 1  further equipped with a light-emitting component; 
           [0020]      FIG. 4  is a schematic sectional view of the high-contrast miniature headlamp in another embodiment of the present invention; and 
           [0021]      FIG. 5  is a schematic sectional view showing the high-contrast miniature headlamp of  FIG. 4  further equipped with a light-emitting component. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0022]    Referring to  FIG. 1 , the high-contrast miniature headlamp  100  in an embodiment of the present invention includes at least one light-emitting element  10 , a first reflective surface  20 , and a second reflective surface  30 . The light-emitting element  10  is fixedly provided at one side of the interior of the high-contrast miniature headlamp  100 . 
         [0023]    As shown in  FIG. 1  and  FIG. 2 , the light-emitting element  10  is fixedly provided at one side of the interior of the high-contrast miniature headlamp  100 . The light-emitting element  10  can be a light-emitting diode (LED) module, wherein the LED module includes at least one LED or at least one organic LED (OLED). 
         [0024]    Referring again to  FIG. 1  and  FIG. 2 , the high-contrast miniature headlamp  100  has one first reflective surface  20 , and the light-emitting element  10  is provided on one side of the first reflective surface  20 . The first reflective surface  20  serves to reflect the light projected thereon by the light-emitting element  10  while the light-emitting element  10  forms a virtual equivalent light source  10 ′ on the other side of the first reflective surface  20 . The first reflective surface  20  can be a flat mirror, a convex mirror, or a concave mirror. 
         [0025]    With continued reference to  FIG. 1  and  FIG. 2 , the second reflective surface  30  of the high-contrast miniature headlamp  100  is fixedly provided adjacent to the light-emitting element  10  but is not directly exposed to the light projected by the light-emitting element  10 . The second reflective surface  30  serves to reflect the light of the light-emitting element  10  that is reflected by the first reflective surface  20 , and light reflected from the second reflective surface  30  propagates outward through an outgoing surface  40 . 
         [0026]    Reference is now made to  FIG. 2 , in which a single light-emitting element  10  is shown by way of example. In the absence of the first reflective surface  20 , light emitted from the light-emitting element  10  directly impinges on and is reflected by a third reflective surface  30 ′ such that an outgoing light beam B 2  is produced. The length of the optical path travelled within the headlamp by the light emitted from the light-emitting element  10  is the sum of the lengths of the optical path sections d 1  and d 2 . 
         [0027]    In the presence of the first reflective surface  20 , however, light emitted from the light-emitting element  10  strikes the first reflective surface  20  while the light-emitting element  10  forms an equivalent light source  10 ′ on the other side of the first reflective surface  20 . More specifically, light emitted from the light-emitting element  10  is reflected by the first reflective surface  20 , cast onto the second reflective surface  30 , and then reflected by the second reflective surface  30  to produce an outgoing light beam B 1 . The length of the optical path travelled within the headlamp by the light emitted from the light-emitting element  10  is the sum of the lengths of the optical path sections d 1 , d 2 , and d 3 . 
         [0028]    In this embodiment, both the first reflective surface  20  and the second reflective surface  30  reflect the light emitted from the light-emitting element  10 . Therefore, the high-contrast miniature headlamp  100  is a headlamp structure capable of secondary reflection. 
         [0029]    In the high-contrast miniature headlamp  100 , the optical path travelled by the light emitted from the light-emitting element  10  is extended (d 1 +d 2 +d 3 &gt;d 1 +d 2 ) in comparison with if the first reflective surface  20  is absent. This extension of the optical path is equivalent to placing the light-emitting element  10  at a farther location from the second reflective surface  30 , with a view to effectively modulating the output beam pattern of the high-contrast miniature headlamp  100 . As a result, the contrast of the cutoff line of the beam pattern output from the high-contrast miniature headlamp  100  is enhanced. 
         [0030]    Moreover, referring to  FIG. 3 , the first reflective surface  20  of the high-contrast miniature headlamp  100  can be further provided with a light-emitting component  50 , wherein the light-emitting component  50  is located at the intersection between the first reflective surface  20  and the optical path from the virtual equivalent light source  10 ′ to the second reflective surface  30 . The light-emitting component  50  can be at least one LED or at least one OLED. 
         [0031]    Thus, the high-contrast miniature headlamp  100  has two light sources (i.e., the light-emitting element  10  and the light-emitting component  50 ) inside. When the light-emitting element  10  and the light-emitting component  50  are a low-beam light source and a high-beam light source respectively, the high-contrast miniature headlamp  100  can provide both low-beam and high-beam illumination with a high-contrast beam pattern. 
         [0032]      FIG. 4  shows another embodiment of the present invention, in which the high-contrast miniature headlamp  200  includes at least one light-emitting element  10  and a light-permeable member  90 . 
         [0033]    The light-emitting element  10  of the high-contrast miniature headlamp  200  is fixedly provided at one side of the light-permeable member  90 , allowing the light emitted from the light-emitting element  10  to enter the light-permeable member  90 . The light-emitting element  10  of the high-contrast miniature headlamp  200  can also be an LED module, wherein the LED module includes at least one LED or at least one OLED. 
         [0034]    As shown in  FIG. 4 , the light-permeable member  90  is fixedly provided adjacent to the light-emitting element  10 , is directly exposed to the light projected by the light-emitting element  10 , and includes a first reflective surface  20  and a second reflective surface  30 . The light-permeable member  90  can be made of glass, sapphire, ceramic, etc. If necessary, the material of the light-permeable member  90  should be so selected that its transmittance matches the intended application. 
         [0035]    As shown in  FIG. 4  and  FIG. 5 , the light-emitting element  10  of the high-contrast miniature headlamp  200  is provided on one side of the first reflective surface  20 . The first reflective surface  20  serves to reflect the light projected thereon by the light-emitting element  10  while the light-emitting element  10  forms a virtual equivalent light source  10 ′ on the other side of the first reflective surface  20 . The first reflective surface  20  can be a flat reflective surface, a convex reflective surface, or a concave reflective surface. 
         [0036]    With continued reference to  FIG. 4  and  FIG. 5 , the second reflective surface  30  is fixedly provided adjacent to the light-emitting element  10  but is not directly exposed to the light projected by the light-emitting element  10 . The second reflective surface  30  serves to reflect the light of the light-emitting element  10  that is reflected by the first reflective surface  20 , and light reflected from the second reflective surface  30  propagates outward through an outgoing surface  40 . 
         [0037]    In the high-contrast miniature headlamp  200 , the first reflective surface  20  extends the optical path travelled by the light emitted from the light-emitting element  10 , and this extension of the optical path is equivalent to placing the light-emitting element  10  at a farther location from the second reflective surface  30 , with a view to effectively modulating the output beam pattern of the high-contrast miniature headlamp  200 . As a result, the contrast of the cutoff line of the beam pattern output from the high-contrast miniature headlamp  200  is enhanced. 
         [0038]    Moreover, referring to  FIG. 5 , the first reflective surface  20  can be further provided with a light-emitting component  50 , wherein the light-emitting component  50  is located at the intersection between the first reflective surface  20  and the optical path from the virtual equivalent light source  10 ′ to the second reflective surface  30 . Likewise, the light-emitting component  50  can be at least one LED or at least one OLED. 
         [0039]    Thus, the high-contrast miniature headlamp  200  has two light sources (i.e., the light-emitting element  10  and the light-emitting component  50 ) inside. When the light-emitting element  10  and the light-emitting component  50  are a low-beam light source and a high-beam light source respectively, the high-contrast miniature headlamp  200  can provide both low-beam and high-beam illumination with a high-contrast beam pattern. 
         [0040]    The embodiments described above are intended only to demonstrate the technical concept and features of the present invention so as to enable a person skilled in the art to understand and implement the contents disclosed herein. It is understood that the disclosed embodiments are not to limit the scope of the present invention. Therefore, all equivalent changes or modifications based on the concept of the present invention should be encompassed by the appended claims.