Patent Publication Number: US-2010110715-A1

Title: Vehicular lamp unit and vehicular lamp

Description:
BACKGROUND OF INVENTION 
     1. Field of the Invention 
     The present invention relates to a vehicular lamp unit and a vehicular lamp of so-called projector-type, and particularly relates to a vehicular lamp unit and a vehicular lamp provided with a shade that forms a cut-off line of a light distribution pattern. 
     2. Related Art 
     Conventionally, as one form of a vehicular lamp such as a headlamp, a so-called projector-type vehicular lamp is known. This projector-type vehicular lamp is structured to collect and reflect light from a light source disposed on an optical axis to the front towards the optical axis using a reflector, and to radiate the reflected light to the front of the lamp via a projection lens provided in front of the reflector. 
     It is common that, when such a projector-type lamp unit is used as a low-beam headlamp, a shade is provided between the projection lens and the light source, and a part of the reflected light from the reflector and a part of direct light from the light source are blocked by the shade, thereby forming a cut-off line of a light distribution pattern. Therefore, for instance, the light that is incident below the reflector and is blocked by the shade becomes loss of light that does not contribute to the light distribution projected forward. Particularly, when a semiconductor light-emitting element is used as the light source, an amount of radiated light is likely to be insufficient. 
     Accordingly, there has been proposed a projector-type lamp unit provided with a main reflector having a first reflective surface that reflects direct light from a light source to the front towards an optical axis, and a sub-reflector including a shade mechanism having a second reflective surface disposed in between a convex lens (projection lens) and the light source and formed in a generally flat shape along an optical axis of the convex lens (for instance, Patent Document 1). 
     With the use of such a lamp unit, by reflecting a part of reflected light from the main reflector upward using the second reflective surface of the sub-reflector, it is possible to effectively utilize the light, which is blocked and thus not used, to perform beam radiation to the lower side of a cut-off line. 
     [Patent Document 1] Japanese Patent Application Laid-Open (Kokai) No. JP-A-2006-107955 
     SUMMARY OF INVENTION 
     However, even when a part of the reflected light from the main reflector is reflected upward by the second reflective surface of the sub-reflector as in the above-described lamp unit, the light cannot be radiated at all above the cut-off line of the light distribution pattern. If the light is not radiated at all above the cut-off line, a forward visibility is not good, and it is hard to recognize an object on an opposite lane. Specifically, radiated light with such a level that the light does not give a glare to a vehicle on the opposite lane is necessary for improving the forward visibility also above a cut-off line in a low-beam light distribution pattern. 
     Accordingly, one or more embodiments of the present invention provide a vehicular lamp unit and a vehicular lamp capable of improving a forward visibility by radiating light also above a cut-off line of a light distribution pattern. 
     One or more embodiments of the present invention relate to a vehicular lamp unit having a projection lens disposed on an optical axis extending in a vehicular longitudinal direction, a light source disposed rearward of a rear side focal point of the projection lens, a reflector reflecting direct light from the light source to the front towards the optical axis, and a shade disposed between the projection lens and the light source and blocking a part of reflected light from the reflector and a part of the direct light from the light source to form a cut-off line of a light distribution pattern. The vehicular lamp unit is characterized by including: a first reflective surface that is formed on a tip portion of the reflector and reflects a part of the direct light from the light source downward to the front of the shade; and a second reflective surface that is formed on the front of the shade and below the rear side focal point of the projection lens, and reflects reflected light from the first reflective surface towards the projection lens so that upward directed radiated light is emitted from the projection lens. In the vehicular lamp unit, the second reflective surface has vertically divided upper-side second reflective surface and lower-side second reflective surface, and radiated light provided by the lower-side second reflective surface radiates above radiated light provided by the upper-side second reflective surface. 
     With the use of the vehicular lamp unit structured as above, after a part of the direct light from the light source is reflected by the first reflective surface formed on the tip portion of the reflector, the light is further reflected towards the projection lens by each of the vertically divided upper-side second reflective surface and lower-side second reflective surface formed on the front of the shade and below the rear side focal point of the projection lens. Subsequently, the light incident on the projection lens from each of the upper-side second reflective surface and the lower-side second reflective surface is emitted as the upward directed radiated light, which enables radiation of two, vertically-divided areas above the cut-off line of the light distribution pattern. 
     In one or more embodiments, it is preferable that, in the vehicular lamp unit structured as above, the first reflective surface have a front-side first reflective surface and a rear-side first reflective surface which are divided in a longitudinal direction, the front-side first reflective surface be formed in a shape of an ellipsoidal reflective surface having a vertical cross-section that is generally ellipsoidal in shape and whose first focal point and second focal point are respectively set to the light source and a position above the rear side focal point of the projection lens, the rear-side first reflective surface be formed in a shape of a parabolic reflective surface having a vertical cross-section that is generally parabolic in shape and whose focal point is set to the light source, and reflected light from the front-side first reflective surface be incident on the upper-side second reflective surface, and reflected light from the rear-side first reflective surface is incident on the lower-side second reflective surface. 
     With the use of the vehicular lamp unit having such a structure, the reflected light from the front-side first reflective surface formed in a shape of an ellipsoidal reflective surface is incident on the upper-side second reflective surface, and the reflected light from the rear-side first reflective surface formed in a shape of a parabolic reflective surface is incident on the lower-side second reflective surface, so that the light can be effectively incident on the upper-side second reflective surface on which it is difficult for the reflected light from the first reflective surface to be incident. 
     Further, it is preferable that, in the vehicular lamp unit structured as above, the upper-side second reflective surface be formed in a shape of a generally flat surface having a linear vertical cross-section, and the lower-side second reflective surface be formed in a shape of a generally curved surface having a curved vertical cross-section and smoothly formed continuously to a lower portion of the upper-side second reflective surface. 
     With the use of the vehicular lamp unit having such a structure, the lower-side second reflective surface formed in a shape of a generally curved surface can effectively reflect the reflected light from the rear-side first reflective surface having a sharp angle towards the projection lens without interfering with the reflected light from the reflector. Further, because the lower-side second reflective surface is smoothly continued to the lower portion of the upper-side second reflective surface, an unevenness is unlikely to occur in the upward directed radiated light emitted from the projection lens. 
     Further, one or more embodiments of the present invention relate to a vehicular lamp characterized in that an entire light distribution pattern is formed by combining a light distribution from the vehicular lamp unit structured as above and a light distribution from another vehicular lamp unit having a light collecting power lower than that of the above vehicular lamp unit. 
     With the use of the vehicular lamp structured as above, when light distributions from a plurality of lamp units are combined to form an entire light distribution pattern, by forming the first reflective surface on the tip portion of the reflector in the light collecting-type lamp unit having a light collecting power higher than that of another vehicular lamp unit, it is possible to minimize an influence on an effective reflective surface of the reflector. 
     With the use of the vehicular lamp unit according to one or more embodiments of the present invention, the light incident on the projection lens from each of the upper-side second reflective surface and the lower-side second reflective surface after being reflected by the first reflective surface is emitted as the upward directed radiated light, which enables radiation of two, vertically-divided areas above the cut-off line of the light distribution pattern. Accordingly, an optimum light distribution pattern can be formed, and, therefore, forward visibility can be improved. 
     Other aspects and advantages of the invention will be apparent from the following description, the drawings and the claims. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a horizontal cross sectional view of a vehicular lamp according to one or more embodiments of the present invention. 
         FIG. 2  is an arrow view along the line II-II in  FIG. 1 . 
         FIG. 3  is a longitudinal sectional view that explains a basic structure of a lamp unit shown in  FIG. 2 . 
         FIG. 4  is an expanded sectional view of a substantial part of the lamp unit shown in  FIG. 3 . 
         FIG. 5  is a lower perspective view of a reflector shown in  FIG. 2 . 
         FIG. 6  is an upper perspective view of a shade shown in  FIG. 2 . 
         FIG. 7  is a view that shows, in a perspective manner, a low-beam light distribution pattern formed on a virtual vertical screen disposed at a position 25 meters (“m”) ahead of the lamp by light radiated from the lamp unit shown in  FIG. 2 . 
     
    
    
     DETAILED DESCRIPTION 
     Hereafter, embodiments of a vehicular lamp unit and a vehicular lamp according to the present invention will be described in detail with reference to accompanying drawings. 
       FIG. 1  is a horizontal cross sectional view of a vehicular lamp according to one or more embodiments of the present invention. 
     A vehicular lamp  100  is a low-beam headlamp, and is structured such that, in a lamp chamber formed of a plain translucent cover  11  and a lamp body  13 , a plurality of lamp units (two are shown) are housed side-by-side. The plurality of lamp units are formed of a lamp unit (vehicular lamp unit)  40  having a high light collecting power and another lamp unit (another vehicular lamp unit)  20  having a light collecting power lower than that of the lamp unit  40 . 
     These lamp units  20 ,  40  are supported in the lamp body  13  via a frame (not shown), and the frame is supported in the lamp body  13  via an aiming mechanism (not shown). 
     The aiming mechanism is a mechanism for finely adjusting attachment positions and attachment angles of these lamp units  20 ,  40 . The aiming mechanism is designed such that when the aiming adjustment is completed, a lens central axis Ax of each of the lamp units  20 ,  40  extends in a downward direction by about 0.5 to 0.6 degrees relative to a vehicular longitudinal direction. 
     As will be described later, the lamp unit  20  forms a diffusion zone formation pattern WZ having horizontal and oblique cut-off lines on an upper end edge thereof. The lamp unit  40  forms a hot zone formation pattern HZ having horizontal and oblique cut-off lines on an upper end edge thereof 
     Specifically, a low-beam light distribution pattern PL formed by the vehicular lamp  100  is designed to be formed as a combined light distribution pattern of the diffusion zone formation pattern WZ and the hot zone formation pattern HZ formed by these two lamp units  20 ,  40  (refer to  FIG. 7 ). 
     These lamp units  20 ,  40 , which serve as low-beam light distribution pattern forming units, are structured as projector-type lamp units each formed of a light source and a projection lens provided on a front side of the light source, as will be described later. 
     Hereinafter, a structure of each of the lamp units  20 ,  40  will be described. 
     Firstly, a structure of the lamp unit  40  will be described. 
       FIG. 2  is an arrow view along the line II-II in  FIG. 1 ,  FIG. 3  is a longitudinal sectional view that explains a basic structure of a lamp unit shown in  FIG. 2 ,  FIG. 4  is an expanded sectional view of a substantial portion of the lamp unit shown in  FIG. 3 ,  FIG. 5  is a lower perspective view of a reflector shown in  FIG. 2 ,  FIG. 6  is an upper perspective view of a shade shown in  FIG. 2 , and  FIG. 7  is a view that shows, in a perspective manner, a low-beam light distribution pattern formed on a virtual vertical screen disposed at a position 25 meters (“m”) ahead of the lamp by light radiated from the lamp unit shown in  FIG. 2 . 
     As shown in  FIG. 2 , the lamp unit  40  includes a projection lens  45  disposed on an optical axis Ax extending in the vehicular longitudinal direction; an LED (light-emitting diode)  25  as a light source disposed rearward of a rear side focal point F of the projection lens  45 ; a reflector  47  that reflects direct light from the LED  25  to the front towards the optical axis Ax; and a shade  49  that is disposed between the projection lens  45  and the LED  25 , and forms a cut-off line of a light distribution pattern by blocking a part of reflected light from the reflector  47  and a part of the direct light from the LED  25 . 
     The LED  25  is a white light-emitting diode having a single light-emitting chip  25   a  whose size is about 1 millimeter (“mm”) square, for instance. The LED  25  is disposed rearward of the rear side focal point F of the projection lens  45 , and directed upward in the vertical direction on the optical axis Ax in the state where the LED  25  is supported by a substrate  33 . 
     As shown in  FIG. 3  and  FIG. 4 , the reflector  47  is a generally dome-shaped member provided on an upper side of the LED  25 , and has a reflective surface  47   a  that collects and reflects light L 1  from the LED  25  to the front towards the optical axis Ax. 
     This reflective surface  47   a  is formed in a shape of an ellipsoidal reflective surface in which the optical axis Ax is set as a central axis. Specifically, this reflective surface  47   a  has a vertical cross-section including the optical axis Ax that is set to be a generally ellipsoidal shape, and an eccentricity thereof is set to gradually increase from the vertical cross-section to a horizontal cross-section. 
     However, rear side vertexes of ellipses forming the respective cross-sections are set at the same position, and the LED  25  is disposed on a first focal point of the ellipse forming the vertical cross-section of this reflective surface  47   a.  Accordingly, it is designed such that the reflective surface  47   a  collects and reflects the light L 1  from the LED  25  to the front towards the optical axis Ax, and, at that time, the light is generally converged on a second focal point of the ellipse on the vertical cross-section including the optical axis Ax. 
     Further, a first reflective surface  53  that reflects a part of the direct light from the 
     LED  25  downward to the front of the shade  49  is formed on a tip portion of the reflector  47 , as shown in  FIG. 5 . 
     The first reflective surface  53  is formed further on a tip portion of an effective reflective surface of the reflective surface  47   a  of the reflector  47 . The first reflective surface  53  has a front-side first reflective surface  51  and a rear-side first reflective surface  52 , which are divided in a longitudinal direction. 
     The front-side first reflective surface  51  is formed in a shape of an ellipsoidal reflective surface having a vertical cross-section that is generally ellipsoidal in shape and whose first focal point and second focal point P are respectively set to the LED  25  and a position above the rear side focal point F of the projection lens  45 . The front-side first reflective surface  51  reflects the light from the LED  25  towards an upper-side second reflective surface  58  of a second reflective surface  60  formed on the front of the shade  49  for left-side light distribution that forms a cut-off line of a light distribution pattern for left-side light distribution and below the rear side focal point F of the projection lens  45 . 
     The rear-side first reflective surface  52  is formed in a shape of a parabolic reflective surface having a vertical cross-section that is generally parabolic in shape and whose focal point is set to the LED  25 . The rear-side first reflective surface  52  reflects the light from the LED  25  towards a lower-side second reflective surface  59  of the second reflective surface  60 . 
     The second reflective surface  60  is formed on the front of the shade  49  and below the rear side focal point F of the projection lens  45 . The second reflective surface  60  reflects the reflected light from the first reflective surface  53  towards the projection lens  45  so that the upward directed radiated light is emitted from the projection lens  45 . 
     Further, the second reflective surface  60  has an upper-side second reflective surface  58  and a lower-side second reflective surface  59 , which are divided in a vertical direction by an imaginary line shown in  FIG. 1  and  FIG. 6 . 
     Accordingly, the reflected light from the front-side first reflective surface  51  is incident on the upper-side second reflective surface  58 , and the reflected light from the rear-side first reflective surface  52  is incident on the lower-side second reflective surface  59 . Subsequently, the radiated light provided by the lower-side second reflective surface  59  formed in a shape of a generally curved surface having a curved vertical cross-section radiates above the radiated light provided by the upper-side second reflective surface  58  formed in a shape of a generally flat surface having a linear vertical cross-section. 
     Note that the lower-side second reflective surface  59  is smoothly formed continuously to a lower portion of the upper-side second reflective surface  58 . 
     Further, the lamp unit  40  is structured such that reflected light L 3  reflected by the front-side first reflective surface  51  and the upper-side second reflective surface  58  radiates “4L, V, 4R” on 2U in a low-beam left-side light distribution pattern with a predetermined amount of light, and reflected light L 4  reflected by the rear-side first reflective surface  52  and the lower-side second reflective surface  59  radiates “8L, V, 8R” on 4U in the pattern with a predetermined amount of light, which is a requirement imposed by European regulations (ECE R112) (refer to  FIG. 7 ). 
     The projection lens  45  is formed of a planoconvex lens that has a convex front side surface and a flat rear side surface. This projection lens  45  is disposed on the optical axis Ax so that the rear side focal point F thereof is positioned on a second focal point of the reflective surface  47   a  of the reflector  47 , as shown in  FIG. 3 . Accordingly, an image on a focal plane including the rear side focal point F is set to be projected forward as an inverted image. 
     In one or more embodiments of the present invention, the shade  49  has a shape of a block that also serves as a supporting frame of the projection lens  45 , and the shade  49  is disposed between the projection lens  45  and the LED  25 , as shown in  FIG. 3  and  FIG. 6 . Further, the shade  49  has a front end edge  49   c  that positions in the vicinity of the rear side focal point F of the projection lens  45  and blocks a part of the reflected light from the reflector  47  to form a cut-off line of the left-side light distribution pattern, and the shade  49  has an upper surface  49   a  that extends rearward from the front end edge  49   c  and reflects a part of the reflected light from the reflector  47  on the upper side. A light control surface  36  to which reflective surface treatment is applied is formed on the upper surface  49   a.    
     Specifically, the shade  49  is designed such that, by reflecting a part of the reflected light from the reflector  47  upward using the light control surface  36 , most of the light to be emitted upward from the projection lens  45  is converted into the light L 2  emitted downward from the projection lens  45 , thereby enhancing a luminous flux utilization factor of the light emitted from the LED  25 . 
     Specifically, the light control surface  36  is formed of a horizontal cut-off formation surface  37   a  extending horizontally in the right direction of a vehicle generally from the optical axis Ax (in the left direction in  FIG. 6 ), an oblique cut-off formation surface  37   b  extending obliquely downward by 15° in the left direction generally from the optical axis Ax (in the right direction in  FIG. 6 ), and a horizontal cut-off formation surface  37   c  extending horizontally in the left direction from the oblique cut-off formation surface  37   b  (in the right direction in  FIG. 6 ). The front end edge (namely, an edge line between the light control surface  36  and a front end surface  49   b  of the shade  49 )  49   c  is formed so as to pass through the rear side focal point F of the projection lens  45 . 
     Further, of the light emitted from the LED  25 , a part of the light reflected by the reflective surface  47   a  of the reflector  47  is incident on the light control surface  36  of the shade  49 , and the remainder of the light is incident directly on the projection lens  45 . At that time, the light incident on the light control surface  36  is reflected upward by the light control surface  36  and incident on the projection lens  45 , whereby the light is emitted as the downward directed light L 2  from the projection lens  45 . 
     Note that the front end edge  49   c  of the shade  49  is formed in a curved shape in which lateral ends of the front end edge  49   c  protrude forward in a plan view so as to correspond to a field curvature of the projection lens  45 . The curved front end edge  49   c  coincides with a focal group of the projection lens  45 . Specifically, the front end edge  49   c  of the shade  49  is formed along the focal group of the projection lens  45 , and a shape of the front end edge  49   c  directly corresponds to a shape of the cut-off line. 
     Further, the aforementioned second reflective surface  60  is integrally formed in the vicinity of the front end edge  49   c  of the shade  49 . 
     Specifically, in the lamp unit  40  of one or more embodiments of the present invention, a part of the direct light from the LED  25  is reflected by the rear-side first reflective surface  52  having a shape of a parabolic reflective surface and the front-side first reflective surface  51  having a shape of an ellipsoidal reflective surface formed on the tip portion of the reflector  47 . Then, the light is reflected towards the projection lens  45  by the upper-side second reflective surface  58  having a shape of a generally flat surface and the lower-side second reflective surface  59  having a shape of a generally curved surface formed on the front of the shade  49  and below the rear side focal point F of the projection lens  45 , as shown in  FIG. 3  and  FIG. 4 . 
     Subsequently, the light incident on the projection lens  45  from the upper-side second reflective surface  58  and the lower-side second reflective surface  59  are emitted as upward directed radiated lights L 3 , L 4 , which radiate above the low-beam light distribution pattern PL. 
     Next, the lamp unit  20  will be described. 
     As shown in  FIG. 1 , the lamp unit  20  includes a light-emitting diode (not shown) as a light source, a reflector  27 , and a projection lens  35 . The light-emitting diode has the same structure as that of the LED  25  of the lamp unit  40 , and is disposed on an optical axis Ax and directed upward in the vertical direction. 
     The reflector  27  is a generally dome-shaped member provided on an upper side of the light-emitting diode. Further, the reflector  27  has a reflective surface having a shape of an ellipsoidal reflective surface that diffuses and reflects light from the light-emitting diode to the front, with low light collecting power compared to that of the reflective surface  47   a  of the reflector  47 . 
     The projection lens  35  is formed of a planoconvex lens that has a convex front side surface and a flat rear side surface. The projection lens  35  is disposed on the optical axis Ax so that a rear side focal point of the projection lens  35  is positioned on a second focal point of the reflective surface of the reflector  27 , and, accordingly, an image on a focal plane including the rear side focal point is set to be projected forward as an inverted image. Note that, because the radiated light from the lamp unit  20  is only required to reach a relatively shorter distance, the projection lens  35  uses a lens whose diameter is smaller than that of the projection lens  45  of the lamp unit  40 . 
     Further, as shown in  FIG. 7 , the diffusion zone formation pattern WZ formed by the lamp unit  20  is a low-beam light distribution pattern for left-hand traffic having a cut-off line CL 1  of a vehicle&#39;s own lane side and a cut-off line CL 3  of an opposite lane side, which extend in a horizontal direction, and an oblique cut-off line CL 2 , on an upper end edge of the diffusion zone formation pattern WZ. 
     Further, the hot zone formation pattern HZ formed by the lamp unit  40  is formed to overlap with the diffusion zone formation pattern WZ, and is a hot zone formation pattern in which a light collecting power is higher than that in the diffusion zone formation pattern WZ. 
     Further, a light distribution pattern  2 UZ is a light distribution pattern in which the reflected light L 3  reflected by the front-side first reflective surface  51  and the upper-side second reflective surface  58  radiates “4L, V, 4R” on 2U in the low-beam left-side light distribution pattern with a predetermined amount of light. Further, a light distribution pattern  4 UZ is a light distribution pattern in which the reflected light L 4  reflected by the rear-side first reflective surface  52  and the lower-side second reflective surface  59  radiates “8L, V, 8R” on 4U in the low-beam left-side light distribution pattern with a predetermined amount of light. 
     Accordingly, the diffusion zone formation pattern WZ, the hot zone formation pattern HZ, and the light distribution patterns  2 UZ and  4 UZ overlap in the illustrated manner, thereby forming the low-beam light distribution pattern PL of the vehicular lamp  100  as a combined light distribution pattern. 
     Specifically, with the use of the vehicular lamp unit  40  of the vehicular lamp  100  according to one or more embodiments of the present invention, a part of the direct light from the LED  25  is reflected by the first reflective surface  53  formed on the tip portion of the reflector  47 , and the light is then reflected towards the projection lens  45  by each of the vertically divided upper-side second reflective surface  58  and lower-side second reflective surface  59  formed on the front of the shade  49  and below the rear side focal point F of the projection lens  45 . Subsequently, the light incident on the projection lens  45  from the upper-side second reflective surface  58  and the lower-side second reflective surface  59  is emitted as the upward directed radiated light L 3 , L 4 , respectively, which enables radiation of two, vertically-divided areas ( 2 UZ and  4 UZ) above the low-beam light distribution pattern PL. 
     Therefore, the vehicular lamp unit  40  can radiate the predetermined amount of reflected light with such a level that the light does not give a glare to a vehicle on the opposite lane, and also onto the two, vertically-divided areas above the low-beam light distribution pattern PL. Accordingly, it is possible to improve the forward visibility by forming an optimum light distribution pattern. 
     Further, when the reflected light from the front-side first reflective surface  51  formed in a shape of an ellipsoidal reflective surface is incident on the upper-side second reflective surface  58 , and the reflected light from the rear-side first reflective surface  52  formed in a shape of a parabolic reflective surface is incident on the lower-side second reflective surface  59  as in the vehicular lamp unit  40  of one or more embodiments of the present invention, the light can be effectively incident on the upper-side second reflective surface  58  on which it is difficult for the reflected light from the first reflective surface  53  to be incident. 
     Further, the upper-side second reflective surface  58  of one or more embodiments of the present invention is formed in a shape of a generally flat surface having a linear vertical cross-section, and the lower-side second reflective surface  59  is formed in a shape of a generally curved surface having a curved vertical cross-section and is smoothly formed continuously to the lower portion of the upper-side second reflective surface  58 . 
     Therefore, the lower-side second reflective surface  59  formed in a shape of a generally curved surface can effectively reflect the reflected light from the rear-side first reflective surface  52  having a sharp angle towards the projection lens  45  without interfering with the reflected light from the reflector  47 . Further, because the lower-side second reflective surface  59  is smoothly continued to the lower portion of the upper-side second reflective surface  58 , an unevenness is unlikely to occur in the upward directed radiated light emitted from the projection lens  45 . 
     Further, the lamp unit  40  of one or more embodiments of the present invention is used as a light collecting-type lamp unit having the highest light collecting power in the vehicular lamp  100  that combines a light distribution from another vehicular lamp unit  20  having a light collecting power lower than that of the lamp unit  40  to form the entire low-beam light distribution pattern PL. 
     Accordingly, in cases that the vehicular lamp  100  combines the light distributions from the plurality of lamp units  20 ,  40  to form the entire low-beam light distribution pattern PL, by forming the first reflective surface  53  on the tip portion of the reflector  47  in the light collecting-type lamp unit  40  having a light collecting power higher than that of another lamp unit  20 , it is possible to minimize an influence on an effective reflective surface of the reflector  47 . 
     Specifically, for instance, the diffusing-type reflector  27  having a low light collecting power is formed with an effective reflective surface larger than that of the light collecting-type reflector  47 , so that the front-side first reflective surface  51  and the rear-side first reflective surface  52 , which are extended in the longitudinal direction, are formed on the tip portion of the reflector  27 . Thus, the first reflective surface  53  blocks a part of the effective reflective surface, which influences a main light distribution pattern. 
     On the contrary, even if the front-side first reflective surface  51  and the rear-side first reflective surface  52 , which are extended in the longitudinal direction, are formed on the tip portion of the light collecting-type reflector  47  having a high light collecting power, the first reflective surface  53  hardly blocks a part of the effective reflective surface to influence the main light distribution pattern. 
     The vehicular lamp unit and the vehicular lamp of the present invention may be modified in structure from the aforementioned embodiments, and various embodiments may be adopted within the spirit of the present invention. 
     For instance, although the vehicular lamp  100  of the aforementioned embodiments is structured such that the plurality of lamp units are housed side-by-side in the lamp chamber, one or more embodiments of the present invention may employ a single lamp unit. Further, the light source is described as a semiconductor light-emitting element such as a light-emitting diode, however, a discharge bulb such as a metal halide bulb and a halogen bulb may also be used. 
     While description has been made in connection with exemplary embodiments of the present invention, it will be obvious to those skilled in the art that various changes and modification may be made therein without departing from the present invention. It is aimed, therefore, to cover in the appended claims all such changes and modifications falling within the true spirit and scope of the present invention. 
     DESCRIPTION OF THE REFERENCE NUMERALS   
       20  LAMP UNIT (ANOTHER VEHICULAR LAMP UNIT) 
       25  LED (LIGHT SOURCE) 
       40  LAMP UNIT (VEHICULAR LAMP UNIT) 
       47  REFLECTOR 
       49  SHADE 
       49   a  UPPER SURFACE 
       49   c  FRONT END EDGE 
       51  FRONT-SIDE FIRST REFLECTIVE SURFACE 
       52  REAR-SIDE FIRST REFLECTIVE SURFACE 
       53  FIRST REFLECTIVE SURFACE 
       45  PROJECTION LENS 
       36  LIGHT CONTROL SURFACE 
       58  UPPER-SIDE SECOND REFLECTIVE SURFACE 
       59  LOWER-SIDE SECOND REFLECTIVE SURFACE 
       60  SECOND REFLECTIVE SURFACE 
       100  VEHICULAR LAMP 
     Ax OPTICAL AXIS 
     CL CUT-OFF LINE 
     CL 1  CUT-OFF LINE OF VEHICLE′S OWN LANE SIDE 
     CL 2  OBLIQUE CUT-OFF LINE 
     CL 3  CUT-OFF LINE OF OPPOSITE LANE SIDE 
     F REAR SIDE FOCAL POINT