Patent Publication Number: US-10781991-B1

Title: Projection headlight

Description:
FIELD 
     The disclosure relates to a headlight, more particularly to a projection headlight. 
     BACKGROUND 
     An ellipsoidal reflector headlamp usually includes at least one light source, e.g. a light emitting diode (LED), a reflective mirror, a light shield and a lens. Generally speaking, a region above a cut-off line of the reflector headlamp is referred to as a dark zone. In order to comply with regulations, the illuminance at the dark zone should be greater than a threshold illuminance to avoid dangerous. For example, when the illuminance at the dark zone is not sufficient for a user to find objects on the road, accidents may thus occur. 
     The reflective mirror and the light shield are usually provided to reflect light beams emitted from the light source to project light through the lens for light compensation at the dark region. The light shield can be categorized into a movable light shield that is electrically controlled to move and a stationary light shield that is mounted fixedly. A stationary light shield is designed to have a specific structure to reflect light and to project light patterns such as high beam and low beam as required. The reflector headlamp is usually mounted in a lamp housing to constitute a conventional headlamp module and then the conventional headlamp module is equipped on a vehicle. For the purpose of versatile and aesthetic appearance of the conventional headlamp module, a housing wall of the lamp housing is usually designed to have many curved structures. However, light beams are refracted by the curved housing wall and the light patterns thus formed are adversely affected. For example, sufficient illuminance at the dark zone cannot be achieved. 
     SUMMARY 
     Therefore, an object of the disclosure is to provide a projection headlamp capable of alleviating at least one of the drawbacks of the prior art. 
     According to one aspect of the disclosure, a projection headlight is provided. The projection headlight includes a reflecting mirror, a light shield, a reflector, a lens and a light emitting unit. The reflecting mirror has amounting space that is defined by a first reflective surface unit. The light shield is disposed in the mounting space and includes a second reflective surface unit facing rearwardly. The reflector is disposed in the mounting space, is disposed behind the light shield and includes a third reflective surface unit facing toward the second reflective surface unit. The lens is disposed in front of the reflecting mirror and the light shield. The light emitting unit is disposed in the mounting space, is disposed behind the light shield, and emits a light beam that is reflected by the first reflective surface unit toward the second reflective surface unit, and that is then reflected by the second reflective surface unit toward the third reflective surface unit to be projected forwardly through the lens. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Other features and advantages of the disclosure will become apparent in the following detailed description of the embodiments with reference to the accompanying drawings, of which: 
         FIG. 1  is a perspective view of a projection headlight according to a first embodiment of the present disclosure and a lamp housing for mounting the headlight thereon; 
         FIG. 2  is an exploded perspective view of the projection headlight of the first embodiment; 
         FIG. 3  is a fragmentary sectional view of the projection headlight of the first embodiment; 
         FIG. 4  is a fragmentary sectional view similar to  FIG. 3 , illustrating paths of light beams being emitted from a first light emitting element of the projection headlight and being reflected to form a low beam pattern; 
         FIG. 5  is a fragmentary sectional view similar to  FIG. 3 , illustrating paths of light beams being emitted from a second light emitting element of the projection headlight and being reflected to form a high beam pattern for light compensation at a dark zone; 
         FIG. 6  is a perspective rear view of a modification of a light shield of the projection headlight the first embodiment; 
         FIG. 7  is a fragmentary perspective view of a reflector and a light shield of the projection headlight according to a second embodiment of the present disclosure; and 
         FIG. 8  is a fragmentary perspective view of a reflecting element and a light shield of the projection headlight according to a third embodiment of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     Before the disclosure is described in greater detail, it should be noted that where considered appropriate, reference numerals or terminal portions of reference numerals have been repeated among the figures to indicate corresponding or analogous elements, which may optionally have similar characteristics. 
     Referring to  FIGS. 1-3 , a projection headlight according to a first embodiment of the present disclosure is mounted in a lamp housing  1 . The lamp housing  1  includes a housing wall  11  and a light transmissive wall  12  mounted on the housing wall  11  transmitting light beams from the projection headlight to project therethrough forwardly. The housing wall  11  includes a plurality of bent portions  111  making the lamp housing  1  to have a certain structural appearance. The projection headlight includes a reflecting mirror  2 , a light shield  3 , a heat dissipating unit  4 , a reflector  5 , a lens  6 , and a light emitting unit  7 . 
     The reflecting mirror  2  includes an upper reflecting portion  21 , a lower reflecting portion  22 , and a first reflective surface unit  23 . The lower reflecting portion  22  is disposed below and cooperates with the upper reflecting portion  21  to define amounting space  20 . The first reflective surface unit  23  includes an upper reflective surface  231  formed on the upper reflecting portion  21  and a lower reflective surface  232  formed on the lower reflecting portion  22 . The upper reflective surface  231  and the lower reflective surface  232  are elliptic reflective surfaces in this embodiment. 
     The light shield  3  is disposed in the mounting space  20 , has a thickness gradually decreased in a front-rear direction (X) in which the lens  6  is spaced apart from the reflecting mirror  2  and includes a second reflective surface unit  31 , a top reflecting surface  32  and a bottom reflecting surface  33 . The light shield  3  and the lens  6  may be integrated as a module but the present disclosure is not limited to this example. 
     The heat dissipating unit  4  includes a base board  41  and a plurality of heat dissipating fins  42 . The base board  41  extends into the mounting space  20 , is disposed between the upper reflecting portion  21  and the lower reflecting portion  22  and is connected thermally to the reflector  5 . The heat dissipating fins  42  are integrally connected to the base board  41  and extend rearwardly from the base board  41 . 
     The reflector  5  is disposed in the mounting space  20 , is disposed behind the light shield  3  and includes a third reflective surface unit  51  facing forwardly toward the second reflective surface unit  31 . The third reflective surface unit  51  is formed with a plurality of light distributing structures  511  arranged side-by-side in a transverse direction (T) transverse to the front-rear direction (X) and configured to distribute light emitted from the light emitting unit  7  in the transverse direction. In this embodiment, each of the light distributing structures  511  is a forward-facing curved surface that is rearwardly concave. By virtue of the light distributing structures  511 , light shape of the projection headlight can be adjusted and distributed evenly to increase range of illumination of in the transverse direction (T). 
     In this embodiment, the reflector  5  is connected thermally to a front end of the base board  41  of the heat dissipating unit  4  and cooperates with the heat dissipating unit  4  to form a single element. Specifically, the third reflective surface unit  51  of the reflector  5  is formed on the front end of the base board  41  by vacuum coating so as to thermally connect the reflector  5  to the heat dissipating unit  4 . As such, an assembly of the reflector  5  and the heat dissipating unit  4  provides reflecting function while performing heat dissipating. 
     The lens  6  is disposed in front of the reflecting mirror  2  and the light shield  3  in the front-rear direction (X). In this embodiment, the lens  6  is a convex lens. 
     The light emitting unit  7  is disposed in the mounting space  20 , is disposed behind the light shield  3  in the front-rear direction (X) and includes a first light emitting element  71  and a second light emitting element  72 . The first light emitting element  71  faces the upper reflecting portion  21 , while the second light emitting element  72  faces the lower reflecting portion  22 . 
     Further referring to  FIG. 4 , the first light emitting element  71  emits a plurality of light beams and paths of the light beams are indicated by dash-dotted lines (A) and (B). The light beams indicated by the dash-dotted lines (A) are reflected by the upper reflective surface  231  of the first reflective surface unit  23  to propagate forwardly and downwardly and then are projected forwardly through the lens  6 . The light beam indicated by the dash-dotted line (B) is first reflected by the upper reflective surface  231  of the first reflective surface unit  23  toward the top reflecting surface  32  of the light shield  3  and then are reflected by the top reflecting surface  32  to project forwardly through the lens  6 . In this way, a low beam pattern complying with regulations is formed. 
     Referring to  FIG. 5 , the second light emitting element  72  emits a plurality of light beams and paths of the light beams are indicated by dash-dotted lines (C) and (D). The light beam indicated by an upmost one of the dash-dotted line (C) is reflected by the lower reflective surface  232  of the first reflective surface unit  23  to propagate forwardly and upwardly and is projected forwardly through the lens  6 . The light beams indicated by the remaining two of the dash-dotted lines (C) are reflected by the lower reflective surface  232  of the first reflective surface unit  23  toward the bottom surface  33  of the light shield  3  and are then reflected by the bottom surface  33  to project forwardly through the lens  6 . Note that a majority of the light beams indicated by the dash-dotted lines (C) are projected to a region above the cut-off line of the projection headlight, which is known as a dark zone. 
     As shown in  FIGS. 4 and 5 , when the first light emitting element  71  and the second light emitting element  72  both emit light, the light beams (A), (B) and (C) form a high beam light pattern complying with the regulations. In sum, when the high beam light pattern is required, both of the first and second light emitting elements  71 ,  72  are turned on to emit light whereas when a low beam light pattern is required (see  FIG. 4 ), only the first light emitting element  71  is required to be turned on. 
     It should be noted that, in  FIG. 5 , the light beam indicated by a dash-dotted line (D) is emitted from the first light emitting element  71 , is reflected by the upper reflective surface  231  of the first reflective surface unit  23  toward the second reflective surface unit  31  of the light shield  3 , and then is reflected by the second reflective surface unit  31  toward the third reflective surface unit  51  to be projected forwardly and upwardly through the lens  6 . The light beam (D) is also projected to a region above the cut-off line to further compensate for the luminance of the dark zone and thus the illumination of the projection headlight is improved and safety in using a vehicle mounted with the projection headlight can be improved. 
     By virtue of the first reflective surface unit  23 , the second reflective surface unit  31  and the third reflective surface unit  51 , light beams emitted from the first and second light emitting elements  71 ,  72  are properly reflected such that a luminance at the dark zone can be compensated. Note that the configuration of the first, second and third reflective surface units  23 ,  31 ,  51  can be modified by adjusting the structure, position and extending angle thereof to obtain a desired light pattern and a light exit angle in order to match the lamp housing  1  designed to have a certain aesthetic appearance. 
     As compared to the conventional headlight described in the background section that includes only two elements for reflecting light (the reflective mirror and the light shield), the projection head light of the present disclosure includes three elements, i.e. the first, second and third reflective surface units  23 ,  31 ,  51 , for reflecting light, and thus an included angle between the light beam reflected by the third reflective surface unit  51  and an optical axis (not shown) of the projection headlight is smaller than an included angle between a light beam reflected by the light shield of conventional headlight and an optical axis thereof. In this way, the light beam emitted through the lens  6  would propagate through the housing wall  11  without being refracted by the bent portions  111 , which will not result in insufficient illumination in the dark zone. 
     Further, it is relatively simple for controlling the optical stability of the projection headlamp of the present disclosure when modifying the design thereof. As a result, a relatively good light compensating effect and integrity and quality of light pattern projected by the projection headlamp can be obtained. In this way, the application range of the projection headlamp of the present disclosure is relatively flexible and the paths of light beams of the projection headlamp can be easily adjusted according the design of the lamp housing  1 . Even if the lamp housing  1  is designed to have many curved structures, the configuration of the first, second and third reflective surface units  23 ,  31 ,  51  can be modified accordingly to obtain a desired light pattern. 
     Additionally, the projection headlight of the present disclosure is capable of providing light patterns of, but not limited to, a low beam and a high beam and can be used for light compensation as required. 
     It should be noted that, the lens  6  has a focal point  61  located behind the lens  6  and the light shield  3  is disposed behind the focal point  61  of the lens  6  such that an image of the light shield  3  would not be formed in front of the projection headlight, i.e., the light shield  3  is not visible in front of the projection headlight, and thus provides a relatively good aesthetic appearance. 
     Referring to  FIG. 6 , a modification of the light shield  3  is shown. The second reflective surface  31  of the modified light shield  3  is formed with a plurality of light distributing surface portions  311  arranged side-by-side in the transverse direction (T) and configured to distribute light emitted from the light emitting unit  7 . Each of the light distributing surface portions  311  is a rearward-facing curved surface that is forwardly concave. By virtue of the light distributing surface portions  311 , light shape of the projection headlight can be adjusted and distributed evenly to increase range of illumination in the transverse direction (T). 
     Referring to  FIG. 7 , the projection headlight of a second embodiment of the present disclosure similar to the first embodiment is shown, and the difference therebetween resides in that the heat dissipating unit  4  of the second embodiment is connected integrally to the reflector  5  and the light shield  3 . 
     Referring to  FIG. 8 , the projection headlight of a third embodiment of the present disclosure is similar to the first embodiment. The difference between the first and third embodiments resides in the structure of the light shield  3  and the reflector  5 . In the third embodiment, each of the light distributing structures  511  of the reflector  5  is a forward-facing curved surface that is forwardly convex and each of the light distributing surface portions  311  of the light shield  3  is a rearward-facing curved surface that is rearwardly convex. By virtue of the light distributing surface portions  311  and the light distributing structures  511 , light emitted from the light emitting unit  7  can be distributed evenly in the transverse direction (T). In this way, the range of illumination of the projection headlamp of the present disclosure in the transverse direction (T) can be increased. Further, the design of the light distributing structures  511  being forwardly convex and the light distributing surface portions  311  being rearwardly convex facilitates simplifying the molds for making the light distributing structures  511  and the light distributing surface portions  311 . In this way, manufacturing cost for molds of the reflector  5  and the light shield  3  can be reduced and the overall manufacturing cost for the projection headlight can thus be reduced. 
     In the description above, for the purposes of explanation, numerous specific details have been set forth in order to provide a thorough understanding of the embodiment(s). It will be apparent, however, to one skilled in the art, that one or more other embodiments may be practiced without some of these specific details. It should also be appreciated that reference throughout this specification to “one embodiment,” “an embodiment,” an embodiment with an indication of an ordinal number and so forth means that a particular feature, structure, or characteristic may be included in the practice of the disclosure. It should be further appreciated that in the description, various features are sometimes grouped together in a single embodiment, figure, or description thereof for the purpose of streamlining the disclosure and aiding in the understanding of various inventive aspects, and that one or more features or specific details from one embodiment may be practiced together with one or more features or specific details from another embodiment, where appropriate, in the practice of the disclosure. 
     While the disclosure has been described in connection with what are considered the exemplary embodiments, it is understood that this disclosure is not limited to the disclosed embodiments but is intended to cover various arrangements included within the spirit and scope of the broadest interpretation so as to encompass all such modifications and equivalent arrangements.