Patent Publication Number: US-7708439-B2

Title: Vehicle headlamp

Description:
The present application claims foreign priority based on Japanese Patent Application No. P.2004-351925, filed on Dec. 3, 2004, the contents of which are incorporated herein by reference. 
   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to a vehicle headlamp capable of realizing both suitable change in light quantity of light and a large quantity of light. 
   2. Related Art 
   There is a vehicle headlamp for projecting light ahead of the vehicle by using a projector type of lamp unit. 
   In such a projector type of lamp unit, a light source is arranged in the vicinity on an optical axis extending in a longitudinal direction of the vehicle. Light emitted from the light source is forward collected/reflected toward the optical axis by a reflector. The reflected light by the reflector is projected ahead of the lamp unit through a projector lens arranged in front of the reflector. A shade is arranged in the vicinity of the focal point on the rear side of the projector lens, and a part of the reflected light from the reflector is cut or shielded to form the cut-off line, so that a distributed light pattern having a cut-off line on the upper end face is formed. (See, for example, JP-A-05-159603). 
   Further, there is a vehicle headlamp called as an AFS (adaptive front lighting system). In the AFS, a position of a movable reflector located within in a lamp unit is appropriately changed to adaptively change a distributed light pattern, so as to realize a distributed light pattern suitable to a vehicle dedicated road (freeway), a distributed light pattern suitable to a bad weather, etc. as required. 
   In the vehicle headlamp for a lower beam (a passing beam) for forming a lower beam distributed light pattern, it is preferable that the quantity of light below an H line is increased to realize a large quantity of light. However, in such a vehicle headlamp, when it is intended to adaptively change the distributed light pattern, it is difficult to realize the collected light with a sufficient quantity of light. For example, even when it is intended to form the collected light in the vicinity of H-V, the collected light with the sufficient quantity of light cannot be formed. 
   SUMMARY OF THE INVENTION 
   One or more embodiments of the present invention provide a vehicle headlamp to realize compatibility between a large quantity of light and collected light, by fully using the quantity of light of a limited light source. 
   In accordance with one or more embodiments of the present invention, a vehicle headlamp is provided with: a light source bulb having a light source for emitting light; a main reflector that reflects the light emitted from the light source; a shade that shields a part of the light reflected by the main reflector; a projector lens that forward projects the light passing the shade; a first sub-reflector that reflects the light emitted from the light source, the first sub-reflector being movable; a second sub-reflector that forward reflects the light from the first sub-reflector through the shade and the projector lens when the first sub-reflector is located in a first position; and a third sub-reflector that forward projects the light from the first sub-reflector not through the projector lens when the first sub-reflector is located in a second position. 
   In addition, in accordance with one or more embodiments of the present invention, the vehicle headlamp may further be provided with: a fourth sub-reflector that reflects the light emitted from the light source toward the second sub-reflector, wherein the second sub-reflector forward projects the light from the fourth sub-reflector through the shade and the projector lens. 
   In addition, in accordance with one or more embodiments of the present invention, in the vehicle headlamp, the shade may change a height of its upper end face according to the position of the first sub-reflector; and the height of the upper end face of the shade may be lower when the first sub-reflector is located in the first position than the height of the upper end face of the shade when the first sub-reflector is located in the second position. 
   In addition, in accordance with one or more embodiments of the present invention, in the vehicle headlamp, the second sub-reflector may be integrally formed with the main reflector, and the second sub-reflector does not intersect a plane including the light source and a central axis of the projector lens. 
   In addition, in accordance with one or more embodiments of the present invention, in the vehicle headlamp, the first sub-reflector may be arranged above the horizontal plane including a central axis of the projector lens; and the third sub-reflector may be arranged below the horizontal plane. 
   In one or more embodiments of the present invention, according to when the light incident on the first sub-reflector is reflected at the first position or at the second position thereof, the region to be illuminated can be changed. Therefore, by forward projecting the light incident on the first sub-reflector as required, a suitable distributed light pattern can be adaptively formed. Concretely, when the first sub-reflector is situated at the first position, collected light is formed and when the first sub-reflector is situated at the second position, diffused light is formed. In this way, as required, the quantity of light below the H line can be increased to realize a large quantity of light or otherwise the collected light with sufficient quantity of light can be collected in the vicinity of the H-V. 
   Other aspects and advantages of the invention will be apparent from the following description and the appended claims. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a view showing the vehicle headlamp according to an embodiment of this invention. 
       FIG. 2  is a top view of the vehicle. 
       FIG. 3  is a sectional view taken in line III-III in  FIG. 1 . 
       FIG. 4  is a sectional view taken in line A-A in  FIG. 2  in a status of shade releasing. 
       FIG. 5  is a sectional view taken in line A-B in  FIG. 2  in a status of shade releasing. 
       FIG. 6  is a sectional view taken in line A-A in  FIG. 2  in a status of shade shielding. 
       FIG. 7  is a sectional view taken in line A-B in  FIG. 2  in the status of shade shielding. 
       FIG. 8  is a partially enlarged longitudinal sectional view of the vehicle headlamp, which explains the positional relationship among focal points. 
       FIG. 9  is a partially enlarged longitudinal sectional view of the vehicle headlamp, which explains the positional relationship among focal points. 
       FIG. 10  is a light path diagram of the vehicle headlamp. 
       FIG. 11  is a light path diagram of the vehicle headlamp. 
       FIG. 12  is a light path diagram of the vehicle headlamp. 
       FIG. 13  is a light path diagram of the vehicle headlamp. 
       FIG. 14  is a light path diagram of the vehicle headlamp. 
       FIG. 15  is a light path diagram of the vehicle headlamp. 
       FIG. 16  is a view showing the distributed light pattern in a status of shade shielding. 
       FIG. 17  is a view showing the distributed light pattern in a status of shade releasing. 
       FIG. 18A  shows the distributed light pattern in a status of shade shielding. 
       FIG. 18B  shows the distributed light pattern in a status of shade releasing. 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   Embodiments of the invention will be described with reference to the accompanying drawings. 
     FIG. 1  is a view showing the vehicle headlamp according to an embodiment of this invention.  FIG. 2  is a top view of the vehicle headlamp according to this embodiment.  FIG. 3  is a sectional view taken in line III-III in  FIG. 1 .  FIG. 4  is a sectional view taken in line A-A in  FIG. 2  in a status of shade releasing.  FIG. 5  is a sectional view taken in line A-B in  FIG. 2  in a status of shade releasing.  FIG. 6  is a sectional view taken in line A-A in  FIG. 2  in a status of shade shielding.  FIG. 7  is a sectional view taken in line A-B in  FIG. 2  in the status of shade shielding.  FIG. 8  is a partially enlarged longitudinal sectional view of the vehicle headlamp, which explains the positional relationship among focal points.  FIG. 9  is a partially enlarged longitudinal sectional view of the vehicle headlamp, which explains the positional relationship among focal points.  FIGS. 10 to 15  are light path diagrams of the vehicle headlamp.  FIG. 16  is a view showing the distributed light pattern in a status of shade shielding.  FIG. 17  is a view showing the distributed light pattern in a status of shade releasing.  FIG. 18A  shows the distributed light pattern in a status of shade shielding.  FIG. 18B  shows the distributed light pattern in a status of shade releasing. 
   As seen from  FIG. 1 , a vehicle headlamp  10  according to this embodiment is constructed of a lamp unit  20  arranged within a lamp room  10   a  which is defined by a lamp body  12  and a light transmissive cover  14  attached to cover the front opening of the lamp body  12 . 
   The lamp unit  20  is a projector type of lamp unit attached to the lamp body  12  through an aiming mechanism not shown, which is designed so that the optical axis of the light emitted from the lamp unit  20  can be regulated by changing the attaching angle of the lamp unit  20  through the aiming mechanism. 
   The lamp unit  20 , as seen from  FIGS. 1 to 5 , mainly includes a projector lens  21 , a first sub-reflector  50 , a rear reflector  30  provided with a main reflector  31  and a second sub-reflector  33 , a third sub-reflector  60 , and a front reflector  40  provided with a fourth sub-reflector  41  and a fifth sub-reflector  43 . 
   In the following description, the respective components will be explained in the order of the projector lens  21 , rear reflector  30 , front reflector  40 , first sub-reflector  50  and third sub-reflector  60 . 
   First, the projector lens  21  will be explained. 
   The projector lens  21  is a lens having a convex lens plane  21   a  on the forward side in a longitudinal direction of a vehicle and a central axis Vx positioned so as to extend along the longitudinal direction of the vehicle. In the lamp unit  20  according to this embodiment, the projector lens  21  is arranged on the most forward side in the longitudinal direction of the vehicle. On the rearward side of the projector lens  21  in the longitudinal direction of the vehicle, the front reflector  40  and rear reflector  30  are arranged in this order. Above the horizontal plane including the central axis Vx of the projector lens  21 , the first sub-reflector  50  is arranged; and below the horizontal plane including the central axis Vx of the projector lens  21 , the third sub-reflector  60  is arranged. 
   Next, the rear reflector  30  will be explained. 
   The rear reflector  30 , as seen from  FIGS. 1 to 3 , is a reflector in a nearly rotary elliptical shape having a front opening  30   a  on the forward side in the longitudinal direction of the vehicle and a lower opening  30   b  on the lower side. On the one side of the rear reflector  30  in the width direction of the vehicle, a though-hole  30   c  is formed in nearly parallel to the width direction of the vehicle. In the through-hole  30   c , a light source bulb  22  is fixedly inserted from the outside of the rear reflector  30  to the inside thereof ( FIG. 3 ). 
   The light source  22  is a discharge bulb such as a metal halide bulb which emits light from a light source  22   a  constructed of a discharge/light-emitting portion within a bulb tube  22   b . As seen from  FIG. 3 , the light source bulb  22  is inserted so that its longitudinal direction has a gradient of 7° from parallelism to the width direction of the vehicle as required along the penetrating direction of the through-hole  30   c . In addition, the light source bulb  22  is fixed so that the light source  22   a  is located on the vertical plane passing the central axis Vx of the projector lens  21 . 
   The rear reflector  30  is integrally composed of the main reflector  31  having a main reflecting face  32  on the inside, i.e. on the forward side in the longitudinal direction and the second sub-reflector  33  having a second sub-reflecting face  34  on the same inside, i.e. on the forward side in the longitudinal direction. In this embodiment, the main reflector  31  and second sub-reflector  33  are integrally formed, but may be formed as separate bodies. 
   The main reflecting face  32  formed on the main reflector  31  is a reflecting face which occupies the greater part of the inside of the rear reflector  30  and has a nearly rotary elliptical shape at least as its vertical sectional shape. The light source  22   a  of the light source bulb  22 , as seen from  FIG. 4 , is arranged in the vicinity of a first focal point (point F 1 ) when the main reflecting face  32  is approximated as the rotary elliptical shape. The main reflecting face  32  reflects the light emitted from the light source  22   a  so that it is collected in the vicinity of the second focal point (point F 2 ). The points in the vicinity of the first focal point (point F 1 ) and second focal point (point F 2 ) of the main reflecting face  32  are arranged in the vertical plane passing the central axis Vx of the projector lens  21 . The rear focal point of the projector lens  21  is arranged so as to nearly agree with the second focal point (point F 2 ) of the main reflecting face  32 . 
   Further, as seen from  FIGS. 2 and 4 , of the inner peripheral surface of the rear reflector  30 , the main reflecting face  32  is formed in the vicinity of plane intersecting the vertical plane at least passing the central axis Vx of the projector lens  21 . 
   The second sub-reflecting face  34  formed on the second sub-reflector  33  is a reflecting face which is partially formed on both sides of the inner face of the rear reflector  30  and has a nearly rotary elliptical shape at least as its vertical sectional shape. On the inner peripheral surface of the rear reflector  30 , an upper concave  34   a  and a lower convex  34   b  are formed on both sides not intersecting the vertical plane passing the central axis Vx of the projector lens  21  in  FIG. 2 . The curved face coupling the concave  34   a  and convex  34   b  constitutes the second sub-reflecting face  34 . 
   Next, the front reflector  40  will be explained. 
   As seen from  FIGS. 1 and 2 , the front reflector  40  is attached to cover the lower part of the forward opening  30   a  of the rear reflector  30 . At the upper portion of the front reflector  40 , an opening  40   a  defined by an upper end  40   b  is made. The upper end  40   b  is located below the central axis Vx of the projector lens  21 . Nearly above the upper end  40   b , the second focal point (point F 2 ) of the main reflecting face  32  is located. On the upper end  40   b  of the front reflector  40 , a rotary shade  45  is arranged. 
   The rotary shade  45  includes a cylindrical body  45   a  whose axis is oriented in the width direction of the vehicle and two shades  46 ,  47  arranged circumferentially apart from each other on the surface of the body  45   a . The body  45   a  is designed to be rotatable along a rotary shaft  45   b  so that as seen from  FIGS. 4 and 6  or  FIGS. 5 and 7 , the two shades  46 ,  47  can be selectively positioned upward in the vertical direction. 
   The shade  46  and the shade  47  are set so that their shade upper end face when they are positioned upward in the vertical direction is situated in the vicinity of the second focal point (point F 2 ) of the main reflecting face  32 . Thus, the shades  46 ,  47  shield a part of the light reflected by the main reflecting face  32  and going to the point F 2  and cause the remaining part to be incident on the projector lens  21 . In this way, the shades  46 ,  47  form cut-off lines corresponding to the respective shapes of the shade upper end faces of the shades  46 ,  47  on the distributed light patterns forward projected. Now, it is assumed that the shade  46  and shade  47  have different lengths protruding from the body  45   a . As shown in comparison in  FIGS. 4 and 6 , the shade  46  is located at a higher position than the shade  47  in their upper end face and so the shade  46  protrudes more upward than the shade  47  does. For this reason, the shade  46  shields a larger quantity of light than the shade  47  to lower the cut-off line projected forward. In the following description, the status in which the shade  46  is oriented to the vertical direction is called “shade shielding status, whereas the status in which the shade  47  is oriented to the vertical direction is called “shade releasing status”. 
   The front reflector  40  has a fourth sub-reflector  41  having a fourth sub-reflecting face  42  on the inside, i.e. at a part of the rearward side in the longitudinal direction of the vehicle. 
   The fourth sub-reflecting face  42  is a reflecting face which is formed to be located at a position ahead of the light source  22   a  in the longitudinal direction of the vehicle and has a nearly rotary elliptical shape. 
   Further, a fifth sub-reflector  43  having a fifth sub-reflecting face  44  with a free curve shape is formed integrally to the lower portion of the fourth sub-reflector  41 . This fifth sub-reflecting face  44  formed on the fifth sub-reflector  43  reflects the incident light from the light source  22   a  toward the vicinity of the light source  22   a  so that the light emitted from the light source  22   a  is returned to the vicinity of the light source  22   a  and emitted in another direction, thereby reducing the non-used light not projected forward and increasing the quantity of light projected forward. 
   Next, the first sub-reflector  50  will be explained. 
   As seen from  FIGS. 1 and 2 , the first sub-reflector  50  is a reflector provided above the front reflector  40 . The first sub-reflector  50  has a first sub-reflecting face  51  with a nearly rotary elliptical shape at least as its vertical sectional shape formed on the lower surface of the first sub-reflector  50 . This sub-reflecting face  51  downward reflects the light from the light source  22   a.    
   The first sub-reflector  50  is designed to be rotatable around a rotary center axis RC by a driving member not shown. For example, the first sub-reflector  50  is designed to be displaceable from a first position where the first sub-reflecting face  51  is oriented obliquely as shown in  FIG. 4  to a second position where the first sub-reflecting face  51  is oriented more obliquely downward as shown in  FIG. 6 . As shown in comparison in  FIGS. 4 and 6  or  FIGS. 5 and 7 , in the shade shielding status, the first sub-reflector  50  is situated at the first position whereas in the shade releasing status, the first sub-reflector  50  is situated at the second position. 
   Next, the third sub-reflector  60  will be explained. 
   As seen from  FIG. 4 , the third sub-reflector  60  is a reflector arranged below the lower opening  30   b  of the rear reflector  30 . The third sub-reflector  60  has a third sub-reflecting face  61  with a nearly parabolic shape as at least its vertical sectional shape formed on the upper surface of the third sub-reflector  60 . Thus, the third sub-reflector  60  forward projects, not through the projector lens  21 , the light reflected by the third sub-reflecting face  61  through the lower opening  30   b.    
   An explanation will be given of the relative optical positional relationship among the main reflecting face  32 , first sub-reflecting face  51 , second sub-reflecting face  34 , third sub-reflecting face  61  and fourth sub-reflecting face  42 . 
   The fourth sub-reflecting face  42  when it is approximated as the rotary elliptical shape is designed so that its first focal point nearly agrees with the light source  22   a , i.e. the first focal point of the main reflecting face  32  and its second focal point (point F 3 ) nearly agrees with the first focal point of the second sub-reflecting face  34 . For this reason, the light reflected by the fourth sub-reflecting face  42  is incident on the second sub-reflecting face  34  in a status where the light collecting optical system of the light incident from the light source  22   a  is kept. 
   The second sub-reflecting face  34  when it is approximated as the rotary elliptical shape is designed so that its first focal point nearly agrees with the second focal point (point F 3 ) of the fourth sub-reflecting face  42  and its second focal point nearly agrees with the second focal point (point F 2 ) of the main reflecting face  32 , i.e. the rear focal point of the projector lens  21 . For this reason, the second sub-reflecting face  34  reflects the light incident from the fourth sub-reflecting face  42  toward the second focal point (point F 2 ) of the main reflecting face  32 . The light come to the point F 2  is selectively shielded by the shade  46  or shade  47  and projected forward by the projector lens  21 . 
   In either case where the sub-reflector  50  is situated the first point as shown in  FIG. 4  or the second position as shown in  FIG. 6 , the first sub-reflecting face  51  is designed so that its first focal point when the fourth sub-reflecting face  42  is approximated as the rotary elliptical shape nearly agrees with the light source  22   a , i.e. first focal point (point F 1 ) of the main reflecting face  32 . On the other hand, the second focal point of the first sub-reflecting face  51  changes according to the position of the first sub-reflector  50 . 
   Concretely, the first sub-reflecting face  50  is situated at the first position shown in  FIGS. 4 and 5 , the second focal point of the first sub-reflecting face  51  nearly agrees with the first focal point of the second sub-reflecting face  34  and the second focal point of the fourth sub-reflecting face  42 , i.e., point F 3 . Therefore, when the first sub-reflector  50  is situated at the first position shown in  FIGS. 4 and 5 , the light reflected by the third reflecting face  61  is incident on the second sub-reflecting face  34  through the first focal point (point F 3 ) of the second sub-reflecting face  34 , and is reflected toward the second focal point (point F 2 ) from the second sub-reflecting face  34 . The light come to the point F 2  is selectively shielded by the shade  47 , and projected forward by the projector lens  21 . 
   On the other hand, the first sub-reflector  50  is situated at the second position shown in  FIGS. 6 and 7 , the second focal point of the first sub-reflecting face  51  is located so that the it nearly agrees with the focal point (point F 4 ) of the third sub-reflecting face  61  of the third sub-reflector  60 . 
   Therefore, when the first sub-reflector  50  is situated at the second position shown in  FIGS. 6 and 7 , the light reflected by the third reflecting face  61  is incident on the first sub-reflecting face  51  through the focal point (point F 4 ) of the third sub-reflecting face  61  and reflected forward as parallel light by the first sub-reflecting face  51 . 
   The first sub-reflector  50  satisfies the above conditions when it satisfies the following condition. 
   (a) The points F 1 , F 3  and F 4  do not reside on the same straight line (see  FIG. 8 ). 
   (b) The points F 1 , F 3  and F 4  reside on the same plane (see  FIG. 9 ). 
   (c) The straight line which passes the center of the circle including the points F 1 , F 3  and F 4  and crosses the circle at right angles agrees with the rotary axis RC of the first sub-reflector  50  (see  FIGS. 8 and 9 ). 
   By rotating the first sub-reflector  50  around the rotary axis RC, with the points F 1 , F 3 , F 4  and rotary axis RC being set so as to satisfy the above condition, it is possible to fix the first focal point of the first sub-reflector  50  at the point F 1  and also change its second focal point from the point F 3  to the point F 4 . 
   Next, referring to  FIGS. 10 to 18B , an explanation will be given of switching of the distributed light pattern by the vehicle headlamp  10  provided with the lamp unit  20  according to this embodiment, light paths within the lamp unit  20  and distributed light patterns to be formed. 
   First, referring to  FIGS. 10 ,  12  and  13 , the light path during the shade releasing will be explained. During the shade releasing, the shade  47  is oriented in the vertical direction and the first sub-reflector  50  is situated at the first position. 
   As seen from  FIG. 10 , the light come from the light source  22   a  to the main reflecting face  32  of the rear reflector  30  is reflected by the main reflecting face  32  toward the vicinity of the second focal point (point F 2 ) of the main reflecting face  32 . The light come to the point F 2  is partially shielded according to the shape of the upper end face of the shade  47 , incident on the projector lens  21  through the point F 2  and projected forward by the projector lens  21 . 
   Further, as seen from  FIG. 12 , the light incident on the fourth sub-reflecting face  42  of the front reflector  40  from the light source  22   a  is incident on the second sub-reflecting face  34  of the rear reflector  30  through the vicinity of the second focal point (point F 3 ) of the fourth sub-reflecting face  42  and reflected toward the vicinity of the second focal point (point F 2 ) of the second sub-reflecting face  34 . The light come to the point F 2  is partially shielded according to the upper end face shape of the shade  47 , incident on the projector lens  21  through the point F 2  and projected forward by the projector lens  21 . 
   Further, as seen from  FIG. 13 , the light incident on the first sub-reflecting face  51  of the first sub-reflector  50  from the light source  22   a  is incident on the second sub-reflecting face  34  of the rear reflector  30  through the second focal point (point F 3 ) of the first sub-reflecting face  51  at the first position, and reflected toward the vicinity of the second focal point (point F 2 ) of the second sub-reflecting face  34 . The light come to the point F 2  is partially shielded according to the upper end face shape of the shade  47 , incident on the projector lens  21  through the point F 2  and projected forward by the projector lens  21 . 
   A distributed light pattern  100  formed during the shade releasing, as seen from  FIG. 16 , includes a basic distributed light region  102  with a cut-off line  101  located above the H line formed by the main reflecting face  32  and a spot region  103  superposed thereon which is projected forward through the fourth sub-reflecting face  42  or first sub-reflecting  51  and the second sub-reflecting face  34  on the region where the H line and V line on the basic distributed light region  102  intersect. 
   This light pattern  100 , in which intense collected light is projected onto the region where the H line and V line intersect, can be used as “motor way distributed light” for illuminating a distant place on a vehicle dedicated road as shown in  FIG. 18A . 
   Next, referring to  FIGS. 11 ,  14  and  15 , the light path during the shade shielding will be explained. During the shade shielding, the shade  46  is oriented in the vertical direction and the first sub-reflector  50  is situated at the second position. 
   As seen from  FIG. 11 , the light incident on the main reflecting face  32  of the rear reflector  30  from the light source  22   a  is reflected by the main reflecting face  32  toward the vicinity of the second focal point (point F 2 ) of the main reflecting face  32 . The light come to the point F 2  is partially shielded by the upper end face shape of the shade  46 , incident on the projector lens  21  through the point F 2  and projected forward by the projector lens  21 . The shade  46 , which projects more upward than the shade  47 , shields a larger quantity of light than the shade  47 , and lowers the cut-off line of the distributed light pattern projected forward. 
   Further, as seen from  FIG. 14 , the light incident on the fourth sub-reflecting face  42  of the front reflector  40  from the light source  22   a  is incident on the second sub-reflecting face  34  of the rear reflector  30  through the vicinity of the second focal point (point F 3 ) of the fourth sub-reflecting face  42  and reflected toward the vicinity of the second focal point (point F 2 ) of the second sub-reflecting face  34 . The light come to the point F 2  is partially shielded according to the upper end face shape of the shade  47 , incident on the projector lens  21  through the point F 2  and projected forward by the projector lens  21 . In this case also, the shade  46 , which projects more upward than the shade  47 , shields a larger quantity of light than the shade  47 . 
   Further, as seen from  FIG. 15 , the light incident on the first sub-reflecting face  51  of the first sub-reflector  50  from the light source  22   a  is reflected by the third sub-reflecting face  61  of the third reflector  60  through the vicinity of the second focal point (point F 4 ) of the first sub-reflecting face  51  at the second position, and forward projected not through projector lens  21 . 
   A distributed light pattern  110  formed during the shade shielding, as seen from  FIG. 17 , includes a basic distributed light region  112  with a cut-off line  111  located above H line formed by the main reflecting face  32 , a spot region  113  superposed thereon which is projected forward through the fourth sub-reflecting face  42  and the second sub-reflecting face  34  in the vicinity of the lower portion of the region where H line and V line on the basic distributed light region  112  intersect, and diffused regions  114  superposed on both sides of the basic distributed light pattern  112  which are forward projected through the first sub-reflecting face  51  and the third sub-reflecting face  61 . 
   Since the upper end face of the shade  46  is nearer to the second focal point (point F 2 ) of the main reflecting face  32  than the upper end face of the shade  47 , the distributed light pattern  110  gives the cut-off line  111  that is clear, and improves distant place visibility by the spot region  113 . 
   In addition, superposition of the diffused regions  114  increases the quantity of light in the lateral direction as shown in  FIG. 18B , thereby improving lateral visibility. In short, the distributed light pattern  110  gives an increased quantity of light below the cut-off line  111 . 
   As understood from the description hitherto made, the vehicle headlamp  10  according to this embodiment has a lamp unit  20  arranged within a lamp room  10   a  constructed by a lamp body  12  and a cover  14 . The lamp unit  20  includes a light source bulb  22  having a light source  22   a  for emitting light, a main reflector  31  provided with the main reflecting surface  32  for reflecting the light emitted from the light source  22   a , a shade  46 ,  47  for shielding a part of the light reflected by the main reflecting face  32  and a projector lens  21  for forward projecting the light having passed the shade  46 ,  47 . The vehicle headlamp  10  according to this embodiment further includes a first sub-reflector  50  having a first sub-reflecting face  51  for reflecting the light emitted from the light source  22   a , the first sub-reflector  50  being movable; a second sub-reflector  33  having a second sub-reflecting face  34  for forward projecting the light from the first sub-reflector  50  through the shade  47  and the projector lens  21  when the first sub-reflector  50  is situated at the first position; and a third sub-reflector  60  having a third sub-reflecting face  61  for forward projecting the light from the first sub-reflector  50  not through the projector lens  21  when the first sub-reflector  50  is situated at the second position. 
   In accordance with this embodiment, the region to be illuminated can be changed between when the light incident on the first sub-reflecting face  51  of the first sub-reflector  50  is reflected at the first position and when it is reflected at the second position. For this reason, as the occasion demands, by appropriately forward projecting the light incident on the first sub-reflecting face  50 , a suitable distributed light pattern can be adaptively formed. Concretely, as in this embodiment, by forming the collected light when the first sub-reflector  50  is situated at the first position and the diffused light when the first sub-reflector  50  is situated at the second position, as the occasion demands, the quantity of light below the H line can be increased, thereby realizing larger quantity of light, or the collected light with sufficient quantity of light can be collected to the vicinity of the H-V. 
   Further, in this embodiment, a fourth sub-reflector  41  having the fourth sub-reflecting face  42  is provided for reflecting the light emitted from the light source  22   a  toward the second sub-reflector  34 , and the second sub-reflecting face  34  forward projects the light from the fourth sub-reflecting face  42  through the shade  46 ,  47  and the projector lens  21 . 
   For this reason, in accordance with this embodiment, the light from the light source  22   a  not projected onto the main reflecting face  32  can be picked up by the fourth sub-reflecting face  42  and second sub-reflecting face  34  so that it can appropriately projected forward. Thus, the quantity of light projected forward is increased, thereby providing a brighter vehicle headlamp. Particularly, in this embodiment, the light picked up by the fourth sub-reflecting face  42  and the second sub-reflecting face  34  is collected as the collected light with a sufficient quantity of light in the vicinity of the H-V. Thus, the quantity of light can be increased in the vicinity of the center of the distributed light pattern, thereby enhancing the distant place visibility. 
   Further, in this embodiment, the movable shade  45  equipped with two shades  46 ,  47  is provided. This movable shade  45  selects the shade  46  or shade  47  according to the position of the first sub-reflector  50  to change the height of its upper end face. Thus, by lowering the height of the shade upper end face, the light can be projected above the H line, thereby realizing the “motor way distributed light” with the distant place visibility. 
   Concretely, the height of the upper end face of the movable shade  45  is lower when the first sub-reflector  50  is situated at the first position than it is situated at the second position. 
   In accordance with such a configuration, where the shade upper end face is lowered, the collected light is formed by the fourth sub-reflecting face  42  and second sub-reflecting face  34 . In addition, the collected light formed by the first sub-reflecting face  51  and the third sub-reflecting face  61  is collected in the vicinity of H-V, thereby enhancing the motor high distributed light with the distant place visibility. 
   Inversely, where the shade upper end face is raised, the collected light is formed by the fourth sub-reflecting face  42  and second sub-reflecting face  34 . In addition, the diffused light is formed by the first sub-reflecting face  51  and the third sub-reflecting face  61  to form the distributed light pattern with a large quantity of light below the H line, thereby realizing the distributed light with the lateral visibility. 
   It will be apparent to those skilled in the art that various modifications and variations can be made to the described preferred embodiments of the present invention without departing from the spirit or scope of the invention. Thus, it is intended that the present invention cover all modifications and variations of this invention consistent with the scope of the appended claims and their equivalents.