Patent Publication Number: US-9423087-B2

Title: Vehicular lamp

Description:
BACKGROUND 
     1. Technical Field 
     The present invention relates to vehicular lamps, and more particularly to vehicular lamps using a light-emitting element such as an LED and a parabolic reflector. 
     2. Related Art 
     Conventionally, vehicular lamps are known which are formed by a plurality of LEDs and a plurality of reflectors each reflecting light from a corresponding one of the LEDs (see, e.g., Patent Document 1). 
     Patent Document 1 
     Japanese Patent Application Laid-Open (Kokai) No. 2011-81975 
     SUMMARY 
     In the case of forming vehicular lamps using an LED and a parabolic reflector, a flat surface to which the LED is attached (hereinafter referred to as the “light source attachment flat surface) is typically provided parallel to the optical axis of the reflector. If the LED and the reflector have a predetermined positional relation, a light ray is emitted in a predetermined optical axis direction of the reflector, and a light distribution pattern is formed at a predetermined position ahead of the vehicle. 
     However, if the attachment position of the LED is shifted from a predetermined position, the positional relation between the LED and the reflector changes, and the light ray may not be emitted in the predetermined optical axis direction, and the light distribution pattern may be shifted from the predetermined position. 
     One or more embodiments of the present invention provides a vehicular lamp capable of suppressing a shift in position of a light distribution pattern due to variation in attachment position of a light source. 
     A vehicular lamp according to one or more embodiments of the present invention includes: a light source attachment flat surface having a plurality of light source attachment portions to which a plurality of light sources are attached; and a plurality of parabolic reflectors each reflecting light from a corresponding one of the light sources in a predetermined optical axis direction. The light source attachment flat surface is tilted with respect to an optical axis of the reflector so as to be higher on a front side of the lamp than on a rear side of the lamp. 
     The light source attachment flat surface may have a first light source attachment portion to which a first light source is attached, and a second light source attachment portion to which a second light source is attached. The plurality of reflectors may include a first reflector that reflects light from the first light source, and a second reflector that reflects light from the second light source. The first reflector may extend from a front end of the second reflector toward a front of the lamp, and the first light source attachment portion and the second light source attachment portion may be placed on the light source attachment flat surface so that the first light source is placed at a focal point of the first reflector and the second light source is placed at a focal point of the second reflector. An f-number of a reflective surface of the second reflector may be smaller than an f-number of a reflective surface of the first reflector. 
     A vehicular lamp according to one or more embodiments of the present invention includes: a light source attachment flat surface having a first light source attachment portion to which a first light source is attached, and a second light source attachment portion to which a second light source is attached; a parabolic first reflector that reflects light from the first light source to a front of the lamp; and a parabolic second reflector that reflects light from the second light source to the front of the lamp. The first reflector extends from a front end of the second reflector toward the front of the lamp, and the first light source attachment portion and the second light source attachment portion are placed on the light source attachment flat surface so that the first light source is placed at a focal point of the first reflector and the second light source is placed at a focal point of the second reflector. An f-number of a reflective surface of the second reflector may be smaller than an f-number of a reflective surface of the first reflector. 
     According to one or more embodiments of the present invention, a vehicular lamp can be provided which is capable of suppressing a shift in position of a light distribution pattern due to variation in attachment position of a light source. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic horizontal cross-sectional view of a vehicular lamp according to one or more embodiments of the present invention. 
         FIG. 2  is an A-A sectional view of the vehicular lamp shown in  FIG. 1 . 
         FIG. 3  is a diagram showing a high beam light distribution pattern that is formed ahead of the lamp by a high beam lamp unit. 
         FIG. 4  is a diagram showing a low beam light distribution pattern that is formed ahead of the lamp by a low beam lamp unit. 
         FIGS. 5( a ) to 5( e )  are diagrams illustrating the relation between variation in attachment position of an LED and variation in light distribution pattern. 
         FIG. 6  is a diagram illustrating how the direction of a light ray that is reflected from a reflector varies according to variation in attachment position of the LED. 
         FIG. 7  is a vertical sectional view of a vehicular lamp according to one or more embodiments of the present invention. 
         FIG. 8  is a perspective view of a circuit board and high beam reflector units. 
         FIG. 9  is a diagram illustrating a modification of the vehicular lamp shown in  FIG. 7 . 
     
    
    
     DETAILED DESCRIPTION 
     Embodiments of the present invention will be described in detail below with reference to the accompanying drawings. In embodiments of the invention, numerous specific details are set forth in order to provide a more thorough understanding of the invention. However, it will be apparent to one of ordinary skill in the art that the invention may be practiced without these specific details. In other instances, well-known features have not been described in detail to avoid obscuring the invention. As used herein, the terms representing the directions such as “upper,” “lower,” “front,” “rear,” “left,” “right,” “inner,” and “outer” mean the directions in an attitude of the vehicular lamp mounted on a vehicle. 
       FIG. 1  is a schematic horizontal cross-sectional view of a vehicular lamp  10  according to an embodiment of the present invention.  FIG. 2  is an A-A sectional view of the vehicular lamp  10  shown in  FIG. 1 . The vehicular lamp  10  shown in  FIG. 1  is a single headlamp that is placed on each of the right and left sides of the front part of the vehicle. Since the right and left vehicular lamps have substantially the same structure, the structure of the vehicular lamp that is placed on the left side of the vehicle will be representatively described below. 
     As shown in  FIGS. 1 and 2 , the vehicular lamp  10  includes a lamp body  12  and a transparent outer cover  13  that covers an opening in the front of the lamp body  12 . The lamp body  12  and the outer cover  13  form a lamp chamber  14 . As shown in  FIG. 1 , the outer cover  13  is shaped to conform to a slant nose shape of the vehicle, and is tilted toward the rear of the vehicle from the inner side toward the outer side of the vehicle. The lamp body  12  is formed in a stepped configuration stepped toward the rear of the vehicle from the inner side toward the outer side of the vehicle according to the shape of the slanted outer cover  13 . Accordingly, the lamp chamber  14  that is formed by the lamp body  12  and the outer cover  13  is a space tilted toward the rear of the vehicle from the inner side toward the outer side of the vehicle. 
     A circuit board  15 , a high beam reflector unit  16 , and a low beam reflector unit  17  are accommodated in the lamp chamber  14 . Each of the circuit board  15 , the high beam reflector unit  16 , and the low beam reflector unit  17  is fixed to a lamp body  12  by a support member, not shown. 
     The circuit board  15  extends from the inner side toward the outer side of the vehicle in the upper part of the lamp chamber  14 . As shown in  FIG. 1 , the circuit board  15  is formed in a stepped configuration stepped toward the rear of the vehicle from the inner side toward the outer side of the vehicle according to the shape of the slanted outer cover  13 . 
     Six LEDs (first to sixth LEDs  18   a  to  18   f ) are mounted on the circuit board  15 . Six light source attachment portions are formed on a light source attachment flat surface  21  as the lower surface of the circuit board  15  in order to mount these six LEDs thereon. Each light source attachment portion may be an electrode for soldering of an electrode of a corresponding one of the LEDs.  FIG. 2  shows a first light source attachment portion  15   a  for attachment of the first LED  18   a . The first to sixth LEDs  18   a  to  18   f  are supplied with a current from the circuit board  15  to emit light. 
     The first to third LEDs  18   a  to  18   c  are LEDs that are used to radiate high beams, and are mounted on the inner side of the vehicle with respect to the center of the circuit board  15 . Of these three LEDs, the first LED  18   a  is provided on the innermost side of the vehicle, the second LED  18   b  is provided outside the first LED  18   a , and the third LED  18   c  is provided outside the second LED  18   b.    
     The fourth to sixth LEDs  18   d  to  18   f  are LEDs that are used to radiate low beams, and are mounted on the outer side of the vehicle with respect to the center of the circuit board  15 . Of these three LEDs, the fourth LED  18   d  is provided on the innermost side of the vehicle, the fifth LED  18   e  is provided outside the fourth LED  18   d , and the sixth LED  18   f  is provided outside the fifth LED  18   e.    
     The high beam reflector unit  16  and the low beam reflector unit  17  are arranged side by side below the circuit board  15  in the lamp chamber  14 . The high beam reflector unit  16  is placed on the inner side of the vehicle, and the low beam reflector unit  17  is placed on the outer side of the vehicle. 
     The high beam reflector unit  16  is a reflector group that is used to radiate high beams, and is formed by three parabolic reflectors, namely a high beam diffusing reflector  16   a , a first high beam condensing reflector  16   b , and a second high beam condensing reflector  16   c . These three reflectors are formed integrally. Of these three reflectors, the high beam diffusing reflector  16   a  is provided on the innermost side of the vehicle, the first high beam condensing reflector  16   b  is provided outside the high beam diffusing reflector  16   a , and the second high beam condensing reflector  16   c  is provided outside the first high beam condensing reflector  16   b.    
     The high beam diffusing reflector  16   a , the first high beam condensing reflector  16   b , and the second high beam condensing reflector  16   c  respectively have reflective surfaces  19   a  to  19   c  each formed based on a paraboloid of revolution. The rotation central axis of each paraboloid of revolution is an optical axis of a corresponding one of the reflectors. That is, the high beam diffusing reflector  16   a  has a first optical axis Ax1, the first high beam condensing reflector  16   b  has a second optical axis Ax2, and the second high beam condensing reflector  16   c  has a third optical axis Ax3. The high beam diffusing reflector  16   a , the first high beam condensing reflector  16   b , and the second high beam condensing reflector  16   c  are placed so that the first optical axis Ax1, the second optical axis Ax2, and the third optical axis Ax3 extend in the longitudinal direction of the vehicle (horizontal direction). 
     The first LED  18   a  is placed at a focal point (located on the first optical axis Ax1) of the reflective surface  19   a  of the high beam diffusing reflector  16   a  (see  FIG. 2 ). The second LED  18   b  is placed at a focal point (located on the second optical axis Ax2) of the reflective surface  19   b  of the first high beam condensing reflector  16   b . The third LED  18   c  is placed at a focal point (located on the third optical axis Ax3) of the second high beam condensing reflector  16   c . Each reflector reflects light from a corresponding one of the LEDs in a direction parallel to the optical axis. 
     The low beam reflector unit  17  is a reflector group that is used to radiate low beams, and is formed by three parabolic reflectors, namely a low beam diffusing reflector  17   a , a first low beam condensing reflector  17   b , and a second low beam condensing reflector  17   c . These three reflectors are formed integrally. Of these three reflectors, the low beam diffusing reflector  17   a  is provided on the innermost side of the vehicle, the first low beam condensing reflector  17   b  is provided outside the low beam diffusing reflector  17   a , and the second low beam condensing reflector  17   c  is provided outside the first low beam condensing reflector  17   b.    
     The low beam diffusing reflector  17   a , the first low beam condensing reflector  17   b , and the second low beam condensing reflector  17   c  respectively have reflective surfaces  20   a  to  20   c  each formed based on a paraboloid of revolution. The rotation central axis of each paraboloid of revolution is an optical axis of a corresponding one of the reflectors. That is, the low beam diffusing reflector  17   a  has a fourth optical axis Ax4, the first low beam condensing reflector  17   b  has a fifth optical axis Ax5, and the second low beam condensing reflector  17   c  has a sixth optical axis Ax6. The low beam diffusing reflector  17   a , the first low beam condensing reflector  17   b , and the second low beam condensing reflector  17   c  are placed so that the fourth optical axis Ax4, the fifth optical axis Ax5, and the sixth optical axis Ax6 extend in the longitudinal direction of the vehicle (horizontal direction). 
     The fourth LED  18   d  is placed at a focal point (located on the fourth optical axis Ax4) of the reflective surface  20   a  of the low beam diffusing reflector  17   a . The fifth LED  18   e  is placed at a focal point (located on the fifth optical axis Ax5) of the reflective surface  20   b  of the first low beam condensing reflector  17   b . The sixth LED  18   f  is placed at a focal point (located on the sixth optical axis Ax6) of the second low beam condensing reflector  17   c . Each reflector reflects light from a corresponding one of the LEDs in a direction parallel to the optical axis. 
     In one or more embodiments of the present invention, the high beam reflector unit  16  and the first to third LEDs  18   a  to  18   c  form a high beam lamp unit that radiates high beams.  FIG. 3  shows a high beam light distribution pattern  30  that is formed ahead of the lamp by the high beam lamp unit. The high beam light distribution pattern  30  shown in  FIG. 3  is a light distribution pattern that is formed on an imaginary vertical screen positioned 25 m ahead of the vehicular lamp  10 .  FIG. 3  shows a vertical line V-V passing through a point H-V as a vanishing point in the forward direction of the lamp, and a horizontal line H-H passing through the point H-V. 
     A high beam condensed light distribution pattern  31  is formed around the point H-V by light reflected by the reflective surface  19   b  of the first high beam condensing reflector  16   b  after being emitted from the second LED  18   b  and light reflected by the reflective surface  19   c  of the second high beam condensing reflector  16   c  after being emitted from the third LED  18   c . The high beam condensed light distribution pattern  31  is an area of high-intensity light which is called “hot zone.” A high beam diffusion light distribution pattern  32  is formed by light reflected by the reflective surface  19   a  of the high beam diffusing reflector  16   a  after being emitted from the first LED  18   a , so as to cover the high beam condensed light distribution pattern  31 . The high beam diffusion light distribution pattern  32  is wider than the high beam condensed light distribution pattern  31  both in the direction of the horizontal line H-H and the direction of the vertical line V-V. The high beam condensed light distribution pattern  31  may be, e.g., an area of about ±10° to 15° in the direction of the horizontal line H-H and about ±3° to 5° in the direction of the vertical line V-V. The high beam diffusion light distribution pattern  32  may be, e.g., an area of about ±25° to 35° in the direction of the horizontal line H-H and about ±8° to 10° in the direction of the vertical line V-V. The high beam light distribution pattern  30  is formed by superimposing the high beam condensed light distribution pattern  31  and the high beam diffusion light distribution pattern  32 . 
     The low beam reflector unit  17  and the fourth to sixth LEDs  18   d  to  18   f  form a low beam lamp unit that radiates low beams.  FIG. 4  shows a low beam light distribution pattern  40  that is formed ahead of the lamp by the low beam lamp unit. The low beam light distribution pattern is a light distribution pattern having a cut-off line of a predetermined shape. 
     A low beam condensed light distribution pattern  41  is formed around the point H-V by light reflected by the reflective surface  20   b  of the first low beam condensing reflector  17   b  after being emitted from the fifth LED  18   e  and light reflected by the reflective surface  20   c  of the second low beam condensing reflector  17   c  after being emitted from the sixth LED  18   f . The low beam condensed light distribution pattern  41  is an area of high-intensity light which is called “hot zone,” and has a cut-off line CL of a predetermined shape. A low beam diffusion light distribution pattern  42  is formed by light reflected by the reflective surface  20   a  of the low beam diffusion reflector  17   a  after being emitted from the fourth LED  18   d , so as to cover the low beam condensed light distribution pattern  41 . The low beam diffusion light distribution pattern  42  is wider than the low beam condensed light distribution pattern  41  both in the direction of the horizontal line H-H and the direction of the vertical line V-V. The low beam condensed light distribution pattern  41  may be, e.g., an area of about ±10° to 15° in the method of the horizontal line H-H and about 0° to −5° in the direction of the vertical line V-V. The low beam diffusion light distribution pattern  42  may be, e.g., an area of about ±25° to 45° in the method of the horizontal line H-H and about 0° to −10° in the direction of the vertical line V-V. The low beam light distribution pattern  40  is formed by superimposing the low beam condensed light distribution pattern  41  and the low beam diffusion light distribution pattern  42 . 
     In one or more embodiments of the present invention, the light source attachment flat surface  21  of the circuit board  15  is tilted with respect to the optical axis of each reflector so as to be higher on the front side of the lamp than on the rear side thereof, as shown in  FIG. 2 . A light-emitting surface of each LED provided on the light source attachment flat surface  21  is also tilted accordingly with respect to the optical axis of each reflector. Since the optical axis of each reflector extends in the longitudinal direction of the vehicle (horizontal direction), an optical axis of each LED which is perpendicular to the light-emitting surface is tilted with respect to the vertical direction of the vehicle (vertical direction). Effects of tilting the light source attachment flat surface  21  with respect to the optical axis of each reflector in this manner will be described below. 
       FIGS. 5( a ) to 5( e )  are diagrams illustrating the relation between variation in attachment position of the LED and variation in light distribution pattern.  FIG. 5( a )  shows variation in position of an LED  51  with respect to a reflector  50 . In the case where the LED  51  is located at a predetermined attachment position  52 , a reflective surface  50   a  of the reflector  50  reflects light from the LED  51  in a direction parallel to an optical axis Ax. In this case, an ideal light distribution pattern  55  about the point H-V is radiated to the front of the lamp, as shown by dotted line in  FIGS. 5( b ) to 5( e ) . 
     In the case where the LED  51  is shifted forward from the predetermined predetermined attachment position  52 , a light distribution pattern  56  shifted upward from the ideal light distribution pattern  55  is radiated to the front of the lamp, as shown in  FIG. 5( b ) . 
     If the LED  51  is shifted rearward from the predetermined attachment position  52 , a light distribution pattern  57  shifted downward from the ideal light distribution pattern  55  is radiated to the front of the lamp, as shown in  FIG. 5( c ) . 
     If the LED  51  is shifted upward from the predetermined attachment position  52 , a light distribution pattern  58  shifted downward from the ideal light distribution pattern  55  is radiated to the front of the lamp, as shown in  FIG. 5( d ) . 
     If the LED  51  is shifted downward from the predetermined attachment position  52 , a light distribution pattern  59  shifted upward from the ideal light distribution pattern  55  is radiated to the front of the lamp, as shown in  FIG. 5( e ) . 
     The inventor of the present application examined such a relation between variation in attachment position of the LED  51  and variation in light distribution pattern, and found out that, if the LED  51  was shifted forward from the predetermined attachment position  52 , shifting the LED  51  upward from the predetermined attachment position  52  could suppress a shift in position of the light distribution pattern from the ideal light distribution pattern  55  because the variations in light distribution pattern resulting from the forward shift and the upward shift cancel each other (see  FIGS. 5( b ) and 5( d ) ). The inventor of the present application also found out that, if the LED  51  was shifted rearward from the predetermined attachment position  52 , shifting the LED  51  downward from the predetermined attachment position  52  could suppress a shift in position of the light distribution pattern from the ideal light distribution pattern  55  because the variations in light distribution pattern resulting from the rearward shift and the downward shift cancel each other (see  FIGS. 5( c ) and 5( e ) ). In the vehicular lamp  10  according to one or more embodiments of the present invention, the light source attachment flat surface is tilted with respect to the optical axis of the reflector based on the above examination. 
       FIG. 6  is a diagram illustrating how the direction of a light ray that is reflected from the reflector varies according to variation in attachment position of the LED. In  FIG. 6 , a light source attachment flat surface  53  is parallel to the optical axis Ax of the reflector  50 , like conventional typical vehicular lamps. On the other hand, a light source attachment flat surface  54  is tilted with respect to the optical axis Ax of the reflector  50  so as to be higher on the front side of the lamp than on the rear side thereof, like the vehicular lamp  10  according to one or more embodiments of the present invention. 
       FIG. 6  shows by solid line a light ray L1 that is emitted from the LED  51  and is reflected at a certain point on the reflective surface  50   a  of the reflector  50  in the case where the LED  51  is attached to a predetermined attachment position. This light ray L1 is parallel to the optical axis Ax of the reflector  50 . 
     In the case of employing the light source attachment flat surface  53  parallel to the optical axis Ax of the reflector  50  as in the conventional examples, a light ray L2 (broken line) emitted from an LED  51   a  shifted forward from the predetermined attachment position and reflected at the certain point on the reflective surface  50   a  of the reflector  50  is significantly shifted upward with respect to the light ray L1. A light ray L3 (dotted line) emitted from an LED  51   b  shifted rearward from the predetermined attachment position and reflected at the certain point on the reflective surface  50   a  of the reflector  50  is significantly shifted downward with respect to the light ray L1. 
     On the other hand, in the case of employing the light source attachment flat surface  54  tilted with respect to the optical axis Ax of the reflector  50  as in one or more embodiments of the present invention, a light ray L4 (chain line) emitted from an LED  51   c  shifted obliquely upward and forward from the predetermined attachment position and reflected at the certain point on the reflective surface  50   a  of the reflector  50  is shifted upward with respect to the light ray L1, but the shift angle is smaller than that of the light ray L2. A light ray L5 (two-dot chain line) emitted from an LED  51   d  shifted obliquely downward and rearward from the predetermined attachment position and reflected at the certain point on the reflective surface  50   a  of the reflector  50  is shifted downward with respect to the light ray L1, but the shift angle is smaller than that for the light ray L3. 
     As described above, according to the vehicular lamp  10  of one or more embodiments of the present invention, the light source attachment flat surface is tilted with respect to the optical axis of the reflector so as to be higher on the front side of the lamp than on the rear side thereof. This can suppress a shift in direction of the light ray even if the mount position of the LED is shifted from the predetermined attachment position. This is because the light source attachment flat surface tilted with respect to the optical axis of the reflector shifts the light ray upward if the LED is shifted forward from the predetermined attachment position, and shifts the light ray downward if the LED is shifted rearward from the predetermined attachment position. This can suppress the shift angle of the direction of the light ray due to the shift in position of the LED, and can suppress a shift in position of the light distribution pattern that is radiated to the front of the lamp. 
     In the case where a plurality of reflectors are formed integrally or a plurality of LEDs are mounted on a single common circuit board as in the vehicular lamp  10  of one or more embodiments of the present invention, it is difficult to adjust the attitude of each reflector to set the direction of the light ray that is emitted from each reflector to an ideal direction. If the attachment positions of a part or all of the LEDs are shifted from their predetermined positions, particularly a part of the light distribution pattern which is located around the point H-V and which should have high light intensity becomes dark. This may reduce long-distance visibility. However, according to the vehicular lamp  10  of one or more embodiments of the present invention, a shift in position of the light distribution pattern can be suppressed. This can ensure high light intensity in the area around the point H-V and can prevent reduction in long-distance visibility. 
     Although the lower surface of the circuit board  15  serves as the light source attachment flat surface  21  in one or more embodiments of the present invention, the light source attachment flat surface  21  is not limited to the surface of the circuit board  15 , and may be, e.g., a flat surface of a heat sink. 
       FIG. 7  is a vertical sectional view of a vehicular lamp  70  according to one or more embodiments of the present invention. The vehicular lamp  70  shown in  FIG. 7  is also a single headlamp that is placed on each of the right and left side of the front part of the vehicle. 
     As shown in  FIG. 7 , the vehicular lamp  70  accommodates a circuit board  71 , high beam reflector units  72 , and low beam reflector units (not shown) in a lamp chamber  14  that is formed by a lamp body  12  and an outer cover  13 . Each of the circuit board  71  and the high beam reflector units  72  is fixed to the lamp body  12  by a support member, not shown. 
       FIG. 8  is a perspective view of the circuit board  71  and the high beam reflector unit  72 . As shown in  FIG. 8 , three high beam reflector units  72  are arranged side by side below the circuit board  71  in the lateral direction of a vehicle. Although not shown in the figure, the plurality of low beam reflector units are also arranged side by side below the circuit board  71  in the lateral direction of the vehicle. 
     Each high beam reflector unit  72  is formed by two parabolic reflectors, namely a high beam diffusing reflector  72   a  and a high beam condensing reflector  72   b . These two reflectors are formed integrally. In one or more embodiments of the present invention, the high beam diffusing reflector  72   a  and the high beam condensing reflector  72   b  are arranged side by side in the vertical direction. As shown in  FIGS. 7 and 8 , the high beam condensing reflector  72   b  extends obliquely downward and forward from a position in the vicinity of the rear part of the circuit board  71 . The high beam diffusing reflector  72   a  extends obliquely downward and forward from the front end of the high beam condensing reflector  72   b.    
     The high beam diffusing reflector  72   a  and the high beam condensing reflector  72   b  respectively have reflective surfaces  73   a  and  73   b  each formed based on a paraboloid of revolution. The rotation central axis of each paraboloid of revolution is an optical axis of a corresponding one of the reflectors. The high beam diffusing reflector  72   a  and the high beam condensing reflector  72   b  have a common optical axis Ax. The high beam diffusing reflector  72   a  and the high beam condensing reflector  72   b  are placed so that the optical axis Ax extends in the longitudinal direction of the vehicle (horizontal direction). In one or more embodiments of the present invention, the f-number (F2) of the reflective surface  73   b  of the high beam condensing reflector  72   b  is smaller than that (F1) of the reflective surface  73   a  of the high beam diffusing reflector  72   a . F2/F1 may be, e.g., about ⅓ to ½. 
     Six LEDs are mounted on the circuit board  71 . Six light source attachment portions are formed on a light source attachment flat surface  74  as the lower surface of the circuit board  71  in order to mount these six LEDs thereon. Three of the six LEDs are diffusing LEDs  75   a  that are used to emit light to the high beam diffusing reflectors  72   a , and the remaining three LEDs are condensing LEDs  75   b  that are used to emit light to the high beam condensing reflectors  72   b.    
     The diffusing LED  75   a  is placed at a focal point of the reflective surface  73   a  of the high beam diffusing reflector  72   a . The condensing LED  75   b  is placed at a focal point of the reflective surface  73   b  of the high beam condensing reflector  72   b . Each reflector reflects light from a corresponding one of the LEDs in a direction parallel to the optical axis Ax. The diffusing LED  75   a  is placed in the front part of the lamp and the condensing LED  75   b  is placed in the rear part of the lamp on the light source attachment flat surface  74 . 
     A high beam condensed light distribution pattern is formed around the point H-V ahead of the vehicle by light reflected by the reflective surfaces  73   b  of the high beam condensing reflectors  72   b  after being emitted from the condensing LEDs  75   b  (see  FIG. 3 ). A high beam diffusion light distribution pattern is formed by light reflected by the reflective surfaces  73   a  of the high beam diffusing reflectors  72   a  after being emitted from the diffusing LEDs  75   a , so as to cover the high beam condensed light distribution pattern. In one or more embodiments of the present invention, a high beam light distribution pattern is formed by superimposing the high beam condensed light distribution pattern and the high beam diffusion light distribution pattern which are formed by the three high beam reflector units  72 . 
     In the case where the high beam diffusing reflector and the high beam condensing reflector are arranged side by side in the vertical direction, separate circuit boards for mounting of the LEDs are normally required for the individual reflectors. This may increase the size in the height direction of the vehicular lamp (vertical direction of the vehicle) in view of the thickness of the circuit boards and clearance between the circuit boards for wiring. According to the vehicular lamp  70  of one or more embodiments of the present invention, the diffusing LED  75   a  and the condensing LED  75   b  can be mounted on the single circuit board  71 , the size in the height direction of the vehicular lamp can be suppressed even if the high beam diffusing reflector and the high beam condensing reflector are arranged side by side in the vertical direction. 
     Although the configuration of the high beam reflector unit  72  is primarily described above, the low beam reflector unit can be configured similarly. The optical system used in the vehicular lamp  70  of one or more embodiments of the present invention can also be used in marker lamps such as a turn signal lamp and a daytime running lamp. 
       FIG. 9  is a diagram illustrating a modification of the vehicular lamp shown in  FIG. 7 . In a vehicular lamp  90  according to the modification, as in the vehicular lamp  10  shown in  FIG. 1 , the light source attachment flat surface  74  of the circuit board  71  is tilted with respect to a first optical axis Ax1 of the high beam diffusing reflector  72   a  and a second optical axis Ax2 of the high beam condensing reflector  72   b  so as to be higher on the front side of the lamp than on the rear side thereof. This configuration can suppress the size in the height direction of the vehicular lamp, and can suppress a shift in position of the light distribution pattern due to a shift in position of the LED. 
     The present invention is described above based on embodiments. It should be understood by those skilled in the art that these embodiments are by way of example only, various modifications can be made to combinations of the components and the processes, and such modifications fall within the scope of the present invention. 
     For example, although the LED is shown as a light source in one or more of the above embodiments, the light source is not limited to the LED, and may be, e.g., a semiconductor laser, a bulb, etc. 
     While the invention has been described with respect to a limited number of embodiments, those skilled in the art, having benefit of this disclosure, will appreciate that other embodiments can be devised which do not depart from the scope of the invention as disclosed herein. Accordingly, the scope of the invention should be limited only by the attached claims. 
     DESCRIPTION OF THE REFERENCE NUMERALS 
     
         
           10 ,  70 ,  90  VEHICULAR LAMP 
           12  LAMP BODY 
           13  OUTER COVER 
           14  LAMP CHAMBER 
           15 ,  71  CIRCUIT BOARD 
           16 ,  72  HIGH BEAM REFLECTOR UNIT 
           17  LOW BEAM REFLECTOR UNIT 
           21 ,  53 ,  54 ,  74  LIGHT SOURCE ATTACHMENT FLAT SURFACE 
           30  HIGH BEAM LIGHT DISTRIBUTION PATTERN 
           31  HIGH BEAM CONDENSED LIGHT DISTRIBUTION PATTERN 
           32  HIGH BEAM DIFFUSION LIGHT DISTRIBUTION PATTERN 
           40  LOW BEAM LIGHT DISTRIBUTION PATTERN 
           41  LOW BEAM CONDENSED LIGHT DISTRIBUTION PATTERN 
           50  REFLECTOR 
           51  LED