Patent Publication Number: US-7722232-B2

Title: Lamp unit of vehicle headlamp

Description:
This application claims foreign priority from Japanese Patent Application No. 2007-079028 filed on Mar. 26, 2007, the entire contents of which are hereby incorporated by reference. 
   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to a lamp unit of a vehicle headlamp, and particularly, relates to a projector-type lamp unit that uses a light-emitting element as a light source. 
   2. Related Art 
   In recent years, even in vehicle headlamps, lamp units that use a light-emitting element, such as a light-emitting diode, as a light source have been adopted. 
   For example, Patent Document 1 discloses a so-called projector-type lamp unit including a projection lens arranged on an optical axis extending in the longitudinal direction of a vehicle, a light-emitting element arranged so as to face upward behind a rear focal point of the projection lens and in the vicinity of the optical axis, and a reflector arranged so as to cover the light-emitting element from above and to reflect the light from the light-emitting element forward toward the optical axis. 
   In such a case, in the lamp unit disclosed in Patent Document 1, a mirror member that has an upward reflecting surface that upward reflects a portion of the reflected light from the reflector, and has a front end edge formed so as to pass through the rear focal point of the projection lens is provided between the reflector and the projection lens. A portion of the reflected light from the reflector is reflected upward by the mirror member, thereby forming a light distribution pattern for low beams that has a cut-off line as an inverted projection image of a front end edge of the upward reflecting surface at its upper end. 
   [Patent Document 1] JP-A-2005-166590 
   In the projector-type lamp unit provided with a mirror member as disclosed in the above Patent Document 1, a light distribution pattern for low beams that has clear cut-off lines at its upper end can be formed while the utilization efficiency of the light from the light-emitting element can be enhanced. 
   However, this lamp unit is configured such that a portion of the reflected light from a rear reflector is reflected upward by the mirror member. Thus, not only a region in the vicinity below the self-lane cut-off line in the light distribution pattern for low beams becomes bright, but also, a region in the vicinity below the opposite-lane cut-off line becomes bright. The light that forms the region in the vicinity below the opposite-lane cut-off line may be regularly reflected by a road surface that gets wet, for instance, during a rainy day and enter driver&#39;s eyes on the opposite lane. The light may enter driver&#39;s eyes on the opposite lane even a vehicle is pitched. Thus, there is a problem in that, if the light is excessively strong, large glare may be given to a driver in the opposite lane. 
   SUMMARY OF THE INVENTION 
   One or more embodiments of the invention provide a lamp unit capable of preventing large glare from being given to a driver in the opposite lane as well as capable of forming a light distribution pattern for low beams that has clear cut-off lines at its upper end, when a projector-type lamp unit that uses a light-emitting element as a light source is adopted as the lamp unit of a vehicle headlamp. 
   One or more embodiments of the invention include a configuration in which a mirror member that upward reflects a portion of the reflected light from a reflector is provided. 
   The lamp unit of a vehicle lamp according to one or more embodiments of the invention includes a projection lens arranged on an optical axis extending in the longitudinal direction of a vehicle, a light-emitting element arranged so as to face upward behind a rear focal point of the projection lens and in the vicinity of the optical axis, and a reflector arranged so as to cover the light-emitting element from above and to reflect the light from the light-emitting element forward toward the optical axis. A mirror member that has an upward reflecting surface that upward reflects a portion of the reflected light from the reflector and has a front end edge formed so as to pass through the rear focal point of the projection lens is provided between the reflector and the projection lens. A region of the upward reflecting surface located nearer the self-lane side than the optical axis is constituted with a horizontal plane including the optical axis. A shielding projection that shields the reflected light from the reflector deflected by the horizontal plane is formed in the position of the horizontal plane that is apart from the front end edge of the upward reflecting surface to the rear side. 
   The above “light-emitting element” means a light source in the shape of an element that has a light-emitting chip that surface-emits light substantially in the shape of a point. The type of the light-emitting element is not particularly limited. For example, a light emitting diode, a laser diode, etc. can be adopted. Further, although the “light-emitting element” is arranged so as to face upward in the vicinity of the optical axis, the light-emitting element is not necessarily arranged so as to face vertically upward. 
   As for the above “upward reflecting surface,” the configuration of a region on the side of the opposite lane in the upward reflecting surface is not particularly limited so long as a region on the side of the self-lane is constituted with a horizontal plane including an optical axis. For example, it is possible to adopt a configuration in which the upward reflecting surface is constituted with a middle slope that extends obliquely downward from the optical axis and a horizontal plane that extends parallel to the above horizontal plane from a lower end edge of the middle slope, the upward reflecting surface is constituted with only an inclined surface that extends obliquely downward from the optical axis, the horizontal plane on the side of the self-lane is formed so as to extend to the opposite lane, or the like. 
   The above “shielding projection” is not particularly limited in terms of its specific configuration, such as the shape or size thereof, or the number of projections to be formed, so long as it is configured to be able to shield a portion of the reflected light of a reflector reflected by the first horizontal plane. Further, even as for the formation position of the “shielding projection,” the specific position of the shielding projection is not particularly limited if it is a “position apart from the front end edge of the upward reflecting surface to the rear side.” 
   The lamp unit of a vehicle headlamp according to one or more embodiments of the invention is constituted as a projector-type lamp unit that uses the light-emitting element as a light source. However, the mirror member that has the upward reflecting surface that upward reflects a portion of the reflected light from the reflector and that is formed so that the front end edge of the upward reflecting surface may pass through the rear focal point of the projection lens is provided between the reflector and the projection lens. Thus, it is possible to form the light distribution pattern for low beams that has clear cut-off lines at its upper end while the utilization efficiency of the light from the light-emitting element can be enhanced. 
   Because a region of the upward reflecting surface on the side of the self-lane is constituted with a first horizontal plane including the optical axis, but a shielding projection that shields a portion of the reflected light from the reflector reflected by the horizontal plane is formed in the position of the horizontal plane that is apart from the front end edge of the upward reflecting surface to the rear side, the following operation effects can be obtained. 
   The light shielded by the shielding projection is the light that forms a region in the vicinity below the opposite-lane cut-off line in the light distribution pattern for low beams. Thus, by preventing this light from being radiated forward, the region in the vicinity below the opposite-lane cut-off line can be prevented from becoming brighter than necessary. Accordingly, even if the light that forms the region in the vicinity below the opposite-lane cut-off line enters driver&#39;s eyes on the opposite lane when the light is regularly reflected by a road surface that gets wet, for instance, during a rainy day or a vehicle is pitched, large glare can be prevented from being given to a driver in the opposite lane. 
   As described above, according to one or more embodiments of the invention, when a projector-type lamp unit that uses a light-emitting element as a light source is adopted as the lamp unit of a vehicle headlamp, large glare can be prevented from being given to a driver in the opposite lane while the light distribution pattern for low beams that has clear cut-off lines at its upper end can be formed. 
   If the end of the upper end face of the upright wall opposite the optical axis is constituted with the inclined surface whose height becomes gradually small in a direction away from the optical axis, the amount of the light shielded by the upright wall can be gradually changed at the end of the upper end face of the upright wall opposite the optical axis. This makes it possible to effectively suppress occurrence of light distribution unevenness at a horizontal outside end in a region in the vicinity below the opposite-lane cut-off line. Particularly, because the horizontal outside end in the region in the vicinity below the opposite-lane cut-off line is low in luminous intensity and is easily conspicuous in light distribution unevenness, as compared with a central portion of the light distribution pattern for low beams, it is especially effective to adopt such a configuration. 
   The formation position of the “shielding projection” is not particularly limited as described above. In one or more embodiments, if the position of the front end edge of the shielding projection is set to the position of 1 to 4 mm from the rear focal point of the projection lens, the portion of the upward reflecting surface located ahead of the shielding projection will ensure the function as the upward reflecting surface. Thus, a portion of the light directed to a region in the vicinity below the opposite-lane cut-off line can be formed efficiently while the cut-off line formed by the front end edge of the upward reflecting surface can be formed clearly. 
   Other aspects and advantages of the invention will be apparent from the following description, the drawings and the claims. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a front view showing a lamp unit of a vehicle headlamp according to one embodiment of the invention. 
       FIG. 2  is a sectional view taken along the line II-II of  FIG. 1 . 
       FIG. 3  is a sectional view taken along the line III-III of  FIG. 1 . 
       FIG. 4  is a detailed view of the portion IV of  FIG. 2 . 
       FIG. 5  is a perspective view when an upright wall of the lamp unit is seen from the oblique upper front left direction. 
       FIG. 6  is a perspective view showing a light distribution pattern for low beams formed on a virtual vertical screen, which is arranged in the position of 25 m ahead of a vehicle, by the light radiated forward from the lamp unit. 
   

   DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS 
   Hereinafter, embodiments of the invention will be described with reference to the accompanying drawings. 
     FIG. 1  is a front view showing a lamp unit  10  according to one embodiment of the invention. Further,  FIG. 2  is a sectional view taken along the line II-II of  FIG. 1 , and  FIG. 3  is a sectional view taken along the line III-III of  FIG. 1 . 
   As shown in these drawings, lamp unit  10  includes a projection lens  12  arranged on an optical axis Ax extending in the longitudinal direction of a vehicle, a light-emitting element  14  arranged behind a rear focal point F of the projection lens  12 , a reflector  16  arranged so as to cover the light-emitting element  14  from above and deflects the light from the light-emitting element  14  forward toward the optical axis Ax, and a mirror member  18  arranged between the reflector  16  and the projection lens  12 , which reflects a portion of the reflected light from the reflector  16  upward. 
   The lamp unit  10  is adapted to be used in a state where it is incorporated as a portion of a vehicle headlamp. In the state where the lamp unit is incorporated into the vehicle headlamp, the lamp unit is arranged in a state where the optical axis Ax thereof extends in a downward direction of about 0.5 to 0.6°with respect to the longitudinal direction of a vehicle. Also, the lamp unit  10  performs optical irradiation for forming a light distribution pattern for low beams of left light distribution. 
   The projection lens  12  includes a planoconvex aspheric lens whose front surface is a convex surface and whose rear surface is a plane surface, and is adapted to project a light source image formed on a rear focal plane (that is, a focal plane including rear focal point F) onto a virtual vertical screen ahead of the lamp as an inverted image. The projection lens  12  is fixed to a ring-shaped lens holder  18 A formed integrally with the mirror member  18  such that it is located ahead of the mirror member  18 . 
   The light-emitting element  14  is a white light diode, and is composed of a light-emitting chip  14   a  having a square light-emitting surface of about 1 mm×1 mm, and a substrate  14   b  that supports the light-emitting chip  14   a.  The light-emitting chip  14   a  is sealed by a thin film formed so as to cover the light-emitting surface. Also, the light-emitting element  14  is positioned and fixed in a recessed portion formed in an upper surface of a rear extension portion  18 B that is formed to extend rearward from the mirror member  18  in a state where the light-emitting chip  14   a  is arranged so as to face vertically upward on the optical axis Ax. 
   A reflecting surface  16   a  of the reflector  16  is constituted with a curved surface substantially in the shape of an ellipsoid that has a major axis that is coaxial with the optical axis Ax, and uses the emission center of the light-emitting element  14  as a first focal point, and the eccentricity of the reflecting surface is set so as to increase gradually toward a horizontal cross section from a vertical cross section. Also, the reflecting surface  16   a  is configured so as to make the light from the light-emitting element  14  converge into a point located slightly ahead of the rear focal point F of the projection lens  12  in the vertical cross section, and to displace the converging position quite forward from the rear focal point F in the horizontal cross section. The reflector  16  is fixed to the upper surface of the rear extension portion  18 B of the mirror member  18  at a peripheral lower end of the reflecting surface  16   a  thereof. 
   The mirror member  18  is constituted as a member in the shape of a substantially flat plate that extends in the horizontal direction, and the upper surface of the mirror member is constituted as an upward reflecting surface  18   a  extending rearward along the optical axis Ax from the rear focal point F. Also, the mirror member  18  reflects a portion of the reflected light from the reflector  16  upward in the upward reflecting surface  18   a  thereof. Further, the upward reflecting surface  18   a  is formed by performing specular processing by aluminum evaporation, etc. on the upper surface of the mirror member  18 . 
   A front end edge  18   b  of the upward reflecting surface  18   a  is formed so as to extend along the rear focal plane of the projection lens  12 . That is, the front end edge  18   b  is formed in a curved manner so as to be displaced gradually forward toward both sides of the optical axis Ax from the rear focal point F in plan view. 
   As for the upward reflecting surface  18   a,  a left region that is located on the left side (on the right side in the front view of the lamp) nearer the self-lane side than the optical axis Ax is constituted with a first horizontal plane  18   a   1  including the optical axis Ax, and a right region that is located on the right side nearer the opposite lane side than the optical axis A is constituted with a second horizontal plane  18   a   2  that is one-step lower than the left region via a middle slope  18   a   3  that extends obliquely downward from the optical axis. The right end and the rear extension portion  18 B that are sufficiently apart from the rear focal point F in the right region are formed so as to be flush with the first horizontal plane  18   a   1  that constitutes the left region. The downward inclination angle of the middle slope  18   a   3  is set to 15°, and the second horizontal plane  18   a   2  is formed so as to be located about 0.4 mm below the first horizontal plane  18   a   1 . 
   As shown in  FIGS. 2 and 3 , the light from the light-emitting element  14  reflected by the reflecting surface  16   a  of the reflector  16  is reflected forward toward the optical axis Ax and enters a lower region of the projection lens  12 . A portion of the light enters the upward reflecting surface  18   a  of the mirror member  18 , is reflected by the upward reflecting surface  18   a,  and then enters an upper region of the projection lens  12 . Then, the light that has entered the lower region or upper region of the projection lens  12  is emitted forward as downward light from the projection lens  12 . 
   Further, an upright wall  30  that extends in the vehicle width direction is formed in a position that is apart rearward from the front end edge  18   b  of the upward reflecting surface  18   a  in the first horizontal-plane  18   a   1  in the upward reflecting surface  18   a.  The upright wall  30  is constituted as a shielding projection that shields a portion of the reflected light from the reflector  16  reflected by the first horizontal plane  18   a   1 . 
     FIG. 4  is a detailed sectional view taken along the line IV-IV of  FIG. 2 . Further,  FIG. 5  is a perspective view when the diffusing and reflecting portion  30  is seen from the oblique front left upper direction. 
   As shown in these drawings, the upright wall  30  is 0.3 to 0.7 mm (for example, 0.5 mm) in height, and 0.5 to 1.5 mm in front-and-rear width (for example, 1 mm), and is formed over a range of 8 to 15 mm (for example, 10 mm) to the left side of the optical axis Ax from near the optical axis Ax. The position of the front end edge of the upright wall  30  is set to a position of 1 to 4 mm (for example, 2 mm) from the rear focal point F. 
   As shown in  FIG. 5 , although an upper end face  30   a  of the upright wall  30  is formed as a horizontal plane, a left end of the upright wall is constituted with an inclined surface  30   a   1  whose height becomes gradually small to the left in a range of 2 to 6 mm (for example, 4 mm). 
   Further, an inclined surface  30   a   2  that extends to the position of a lower end edge of the middle slope  18   a   3  is formed at a right end at the upper end face  30   a  of the upright wall  30  so as to extend at a larger inclination angle than the downward inclination angle of the middle slope  18   a   3  of the upward reflecting surface  18   a.  However, an upper end of the inclined surface  30   a   2  is constituted with a convex surface that protrudes upward so as to be adjacent to the left side of the optical axis Ax. 
   By forming the upright wall  30 , as shown in  FIG. 4 , the reflected light from the reflector  16  that has entered a rear end face of the upright wall  30  is shielded. Also, in the reflected light from the reflector  16  that has entered the first horizontal plane  18   a   1  of the upward reflecting surface  18   a,  the light that has entered the first horizontal plane  18   a   1  in the vicinity of the rear of the upright wall  30  and that is reflected upward is shielded by the rear end face of the upright wall  30 . The reflected light from the reflector  16  that has entered the upper end face  30   a  of the upright wall  30  will be reflected upward by the upper end face  30   a,  and will enter the projection lens  12 . 
   As indicated by two-dot chain lines in this drawing, supposing that the upright wall  30  is not formed, the light shielded by the upright wall  30  is the light passing through the rear focal plane of the projection lens  12  near above the front end edge  18   b  of the upward reflecting surface  18   a.  Thus, the light radiated to a position nearer the line V-V line in the vicinity of below the opposite-lane cut-off line CL 1  will be reduced due to the existence of the upright wall  30 . 
   In addition, as shown in  FIG. 5 , a portion of the surface of a recessed bent portion  18 C located below the front end edge  18   b  of the upward reflecting surface  18   a  of the mirror member  18  is constituted as a roughened portion  18   c  that is subjected to roughening by sandblasting, embossing, etc. The roughened portion  18   c  is formed in a region substantially in the shape of a bow with a portion of the front end edge  18   b  of the upward reflecting surface  18   a  as an upper chord. By forming the roughened portion  18   c  in the surface of the recessed bent portion  18 C in this way, generation of glare light is effectively suppressed. 
   The surface of the recessed bent portion  18 C along with the upward reflecting surface  18   a  is subjected to polishing, such as aluminum vapor deposition. Thus, of the reflected light from the reflector  16  that has reached the projection lens  12 , the light that does not enter the projection lens  12 , but is reflected by the rear surface of the projection lens, and has entered the surface of the recessed bent portion  18 C is again reflected by the surface and is radiated forward as stray light from the projection lens  12 , which may become glare light. Thus, by forming the roughened portion  18   c  in the surface of the recessed bent portion  18 C, much of the light that has entered the recessed bent portion  18 C is made to be irregularly reflected by the roughened portion  18   c,  thereby preventing the light that may become the cause of glare from being radiated forward from the projection lens  12 . 
   In the region of the roughened portion  18   c  located in just below the optical axis Ax, a plurality of diffusing and reflecting elements  18   d  that extend in the up-and-down directions in the shape of a convex circular-arc horizontal section are formed. Accordingly, after the light that is reflected by the rear surface of the projection lens  12 , and has entered the roughened portion  18   c  is irregularly reflected, a portion of the light is diffused and reflected in the horizontal direction by the plurality of diffusing and reflecting elements  18   d.  As a result, generation of glare light is more effectively suppressed. 
     FIG. 6  is a perspective view showing a light distribution pattern PL for low beams formed on a virtual vertical screen, which is arranged in the position of 25 m ahead of a vehicle, by the light radiated forward from the lamp unit  10  according to one or more embodiments. 
   As shown in this drawing, the light distribution pattern PL for low beams is a light distribution pattern for low beams of left light distribution, and has cut-off lines CL 1 , CL 2 , and CL 3  with a right-and-left height difference at its upper end edge. 
   The cut-off lines CL 1 , C-L 2 , and CL 3  extend in the horizontal direction with a right-and-left height difference, with the line V-V that is a vertical line that passes through H-V that is a vanishing point ahead of the lamp as a borderline. On the right side of the line V-V, the cut-off line CL 1  on the side of the opposite lane is formed so as to extend in the horizontal direction, and on the left side of the line V-V, the cut-off line CL 2  on the side of the self-lane is formed so as to extend in the horizontal direction such that it is one-step higher than the cut-off line CL 1  on the side of the opposite lane. Also, the end of the self-lane cut cut-off line CL 2  nearer the line V-V is formed as an oblique cut-off line CL 3 . The oblique cut-off line CL 3  extends at an inclination angle of 15° obliquely in the upper left direction from the point of intersection between the opposite-lane cut-off line CL 1  and the line V-V. 
   In this light distribution pattern P for low beams, an elbow point E that is a point of intersection between the low-stage cut-off line CL 1  and the line V-V is located about 0.5 to 0.6° below H-V. This is because the optical axis Ax extends in a downward inclined direction of about 0.5 to 0.6° with respect to the longitudinal direction of a vehicle. In this light distribution pattern PL for low beams, a hot zone HZ that is a high luminous-intensity region is formed so as to surround the elbow point E nearer the left. 
   The light distribution pattern PL for low beams is formed by projecting an image of the light-emitting element  14 , which is formed on the rear focal plane of the projection lens  12  by the light from the light-emitting element  14  reflected by the reflector  16 , as an inverted projection image onto the above virtual vertical screen by means of the projection lens  12 , and the cut-off lines CL 1 , CL 2 , and CL 3  are formed as an inverted projection image of the front end edge  18   b  of the upward reflecting surface  18   a  of the mirror member  18 . 
   The light distribution pattern PL for low beams is a combined light pattern of a light distribution pattern formed by the light that has directly entered a lower region of the projection lens  12  in the light from the light-emitting element  14  reflected by the reflecting surface  16   a  of the reflector  16 , and a light distribution pattern formed by the light that has entered an upper region of the projection lens  12  after being reflected by the upward reflecting surface  18   a  of the mirror member  18 . 
   In this light distribution pattern PL for low beams, the reason why the hot zone HZ is formed so as to surround the elbow point E to the left is because the light radiated toward the position (the region A indicated by a broken line in this drawing) nearer the line V-V in the vicinity of below the opposite-lane cut-off line CL 1  is reduced due to the existence of the upright wall  30  formed in the mirror member  18 . 
   Thus, the light radiated toward the region A in the vicinity of below the opposite-lane cut-off line CL 1  is reduced by the existence of the upright wall  30 . Accordingly, even if the light that forms the region A enters driver&#39;s eyes on the opposite lane when the light is regularly reflected by a road surface that gets wet, for instance, during a rainy day or when a vehicle is pitched, the glare to a driver in the opposite lane will be reduced. 
   As described in detail above, the lamp unit  10  of a vehicle headlamp according to one or more embodiments is constituted as a projector-type lamp unit  10  that uses the light-emitting element  14  as a light source. However, the mirror member  18  that has the upward reflecting surface  18   a  that upward reflects a portion of the reflected light from the reflector  16  and that is formed so that the front end edge  18   b  of the upward reflecting surface  18   a  may pass through the rear focal point F of the projection lens  12  is provided between the reflector  16  and the projection lens  12 . Thus, it is possible to form the light distribution pattern P 1  for low beams that has clear cut-off lines CL 1 , CL 2 , and CL 3  at its upper end, while it is possible to enhance the utilization efficiency of the light from the light-emitting element  14 . 
   The self-lane region in the upward reflecting surface  18   a  is constituted with the first horizontal planes  18   a   1  including the optical axis Ax, and the opposite-lane region in the upward reflecting surface  18   a  is constituted with the middle slope  18   a   3  extending obliquely downward from the optical axis Ax, and the second horizontal plane  18   a   2  extending parallel to the first horizontal plane  18   a   1  from the lower end edge of the middle slope. However, because the upright wall  30  extending in the vehicle width direction is formed as a shielding projection that shields a portion of the reflected light from the reflector  16  reflected by the first horizontal plane  18   a   1 , in a position apart from the front end edge  18   b  of the upward reflecting surface  18   a  to the rear side in the first horizontal plane  18   a   1 , the following operation effects can be obtained. 
   The light shielded by the upright wall  30  is the light that forms a region in the vicinity below the opposite-lane cut-off line CL 1  in the light distribution pattern PL for low beams. Thus, by preventing this light from being radiated forward, the region in the vicinity below the opposite-lane cut-off line CL 1  can be prevented from becoming brighter than necessary. Accordingly, even if the light that forms the region A in the vicinity below the opposite-lane cut-off line CL 1  enters driver&#39;s eyes on the opposite lane when the light is regularly reflected by a road surface that gets wet, for instance, during a rainy day or when a vehicle is pitched, large glare can be prevented from being given to a driver on the opposite lane. 
   As described above, according to one or more embodiments, when a projector-type lamp unit that uses a light-emitting element as a light source is adopted as the lamp unit  10  of a vehicle headlamp, large glare can be prevented from being given to a driver on the opposite lane while the light distribution pattern for low beams that has clear cut-off lines CL 1 , CL 2 , and CL 3  at its upper end can be formed. 
   Moreover, in the present embodiment, the end of the upper end face  30   a  of the upright wall  30  opposite the optical axis Ax is constituted with the inclined surface  30   a   1  whose height becomes gradually small in a direction away from the optical axis Ax. Thus, the amount of the light shielded by the upright wall  30  can be gradually changed at the end of the upper end face of the upright wall opposite the optical axis. Accordingly, it is possible to effectively suppress that light distribution unevenness may be caused at a horizontal outside end (that is, right end) in the region A in the vicinity below the opposite-lane cut-off line CL 1 . Particularly, because the horizontal outside end in this region A is low in luminous intensity and is easily conspicuous in light distribution unevenness, as compared with a central portion of the light distribution pattern PL for low beams, it is especially effective to adopt such a configuration. 
   In addition, in one or more embodiments, the height of the upright wall  30  is set to 0.3 to 0.7 mm, and the position of the front end face of the upright wall  30  is set to the position of 1 to 4 mm from the rear focal point F of the projection lens  12 . Thus, the portion adjacent to front end edge  18   b  in the upward reflecting surface  18   a  will ensure the function as the upward reflecting surface  18   a.  Accordingly, the glare to be given to a driver on the opposite lane can be reduced while the cut-off lines CL 1 , CL 2 , and CL 3  formed by the front end edge  18   b  of the upward reflecting surface  18   a  can be formed clearly. 
   Furthermore, in one or more embodiments, the inclined surface  30   a   2  is formed at the end of the upper end face  30   a  of the upright wall  30  on the side of the optical axis Ax so as to extend to the position of the lower end edge of the middle slope  18   a   3  of the upward reflecting surface  18   a  at a slightly larger inclination angle than the downward inclination angle of the middle slope  18   a   3  of the upward reflecting surface  18   a,  and an upper end of the inclined surface  30   a   2  is constituted with a convex surface that protrudes upward so as to be adjacent to the left side of the optical axis Ax. Thus, the region A in the vicinity below the opposite-lane cut-off line CL 1  can be formed so as to extend to near the line V-V without causing a hindrance to formation of the oblique cut-off line CL 3 . Accordingly, the glare to a driver on the opposite lane can be reduced effectively. 
   Although the description of the above embodiments has been made with respect to the case where the upright wall  30  extending the vehicle width direction is formed as a shielding projection that shields a portion of the reflected light from the reflector  16  reflected by the first horizontal plane  18   a   1 , it is also possible to adopt a configuration where one or a plurality of boss-like projections are formed as the shielding projection. 
   Although the description of the above embodiments has been made with respect to the case where the light-emitting chip  14   a  of the light-emitting element  14  has a square light-emitting surface of 1 mm×1 mm, a configuration which the light-emitting chip has a light-emitting surface of other shapes or sizes than the above ones can also be adopted, and a plurality of the light-emitting chips  14   a  can also be arranged adjacent to one another. 
   Moreover, although the description of the above embodiments has been made about the case where the upward reflecting surface  18   a  is formed so as to rearward extend along the optical axes Ax from the position of the rear focal point F, it is also possible to adopt a configuration in which the upward reflecting surface  18   a  is formed in a slightly (for example, about 1.5°) front lower direction with respect to the longitudinal direction of a vehicle. By adopting such a configuration, a mold can be easily extracted when the mirror member  18  is molded, and more of the reflected light from the reflector  16  reflected by the upward reflecting surface  18   a  can be made to enter the projection lens  12 . 
   In addition, the numeric values shown as dimensional data in the above embodiments are just illustrative, and it is natural that the values may be set to suitably different values. 
   While description has been made in connection with 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. 
   REFERENCE NUMERALS 
   
       
         10 : LAMP UNIT 
         12 : PROJECTION LENS 
         14 : LIGHT-EMITTING ELEMENT 
         14   a:  LIGHT-EMITTING CHIP 
         14   b:  SUBSTRATE 
         16 : REFLECTOR 
         16   a:  REFLECTING SURFACE 
         18 : MIRROR MEMBER 
         18 B: REAR EXTENSION PORTION 
         18 C: RECESSED BENT PORTION 
         18   a:  UPWARD REFLECTING SURFACE 
         18   a   1 : FIRST HORIZONTAL PLANE 
         18   a   2 : SECOND HORIZONTAL PLANE 
         18   a   3 : MIDDLE SLOPE 
         18   b:  FRONT END EDGE 
         18   c:  ROUGHENED PORTION 
         18   d:  DIFFUSING AND REFLECTING ELEMENT 
         30 : UPRIGHT WALL AS SHIELDING PROJECTION 
         30   a:  UPPER END FACE 
         30   a   1 ,  3 O a   2 : INCLINED-SURFACE 
       A: REGION 
       Ax: OPTICAL AXIS 
       CL 1 : OPPOSITE-LANE CUT-OFF LINE 
       CL 2 : SELF-LANE CUT-OFF LINE 
       CL 2 : OBLIQUE CUT-OFF LINE 
       E: ELBOW POINT 
       F: REAR FOCAL POINT 
       HZ: HOT ZONE 
       PL: LIGHT DISTRIBUTION PATTERN FOR LOW BEAMS