Abstract:
An apparatus includes a light chamber defined by a lamp body and a front cover. The apparatus houses a projection-type light source unit which integrates a reflector, a light source disposed in the vicinity of a first focal point of the reflector, a convex lens disposed in front of the reflector, and an extension reflector. The convex lens is disposed such that light external from the lamp chamber enters the lamp chamber and is reflected out through the convex lens.

Description:
CROSS-REFERENCE 
   This claims the benefit of Japanese patent Application No. 2002-191934 filed Jul. 1, 2002, which is incorporated herein in its entirety. 
   TECHNICAL FIELD OF THE INVENTION 
   The present invention relates to a vehicular headlamp having a projection-type light source unit integrating a reflector, a light source, and a convex lens. The reflector is opened forward and has a substantially ellipsoidal reflecting surface. The convex lens is disposed in front of the reflector via a cylindrical lens holder. 
   BACKGROUND OF THE INVENTION 
     FIG. 10  shows a headlamp that has a lamp chamber s defined by a container-shaped lamp body  1  and a transparent front cover  2 . The headlamp houses a light source unit integrating a reflector  3 , a light source  4 , and a convex lens  6  disposed in front of the reflector  3  via a lens holder  5 . 
   However, the light source unit of this headlamp is substantially sealed. Therefore, when the headlamp is not lit, the convex lens  6  of the light source unit appears dim through the front cover  2 . 
   An extension reflector  7  has been provided around the light source unit to improve the overall appearance such that the entire interior of the light chamber s is provided with specular color when the headlamp is not lit. However, the dimness of the convex lens  6  is instead emphasized with respect to the brightness of the entire interior of the light chamber s. 
   SUMMARY OF THE INVENTION 
   In a vehicular headlamp according to an embodiment of the present invention, a lamp chamber defined by a lamp body and a transparent front cover houses a projection-type light source unit integrating a reflector which is opened forward and has a substantially ellipsoidal reflecting surface, a light source disposed in the vicinity of a first focal point of the reflector, and a convex lens disposed in front of the reflector via a cylindrical lens holder, and an extension reflector disposed to surround the light source unit. 
   The lens holder is provided with an upper opening portion. The extension reflector extends to the rear of the upper opening portion of the lens holder. Therefore, during daytime, light transmitted through the front cover and reaching the interior of the lamp chamber enters the interior of the projection-type light source unit via the upper opening portion of the lens holder, without being shielded by the extension reflector. Accordingly, the interior of the projection-type light source unit appears bright, and thus the convex lens of the light source unit seen through the front cover does not appear as dim as in conventional cases. In particular, because of the extension reflector disposed around the light source unit, the entire interior of the lamp chamber appears bright with specular color, which visually improves the appearance of the headlamp. 
   In a vehicular headlamp according to another embodiment of the present invention, a lamp chamber defined by a lamp body and a transparent front cover houses a projection-type light source unit integrating a reflector which is opened forward and has a substantially ellipsoidal reflecting surface, a light source disposed in the vicinity of a first focal point of the reflector, a convex lens disposed in front of the reflector via a cylindrical lens holder, and a second reflector which is disposed above the light source unit and has a second light source. 
   The lens holder is provided with an upper opening portion, and the second reflector is disposed at a rear part of the upper opening portion of the lens holder which has a second light source. 
   During daytime, light transmitted through the front cover and reaching the interior of the lamp chamber enters the interior of the projection-type light source unit via the upper opening portion of the lens holder, without being shielded by the second reflector above the projection-type light source unit. Accordingly, the interior of the projection-type light source unit appears bright. Thus, the convex lens of the light source unit seen through the front cover does not appear as dim as in conventional cases. 
   A vehicular headlamp according to another embodiment of the present invention is structured such that a glare light protection shade for shielding glare light that passes through the upper opening portion and radiates outward is provided between the light source and the upper opening portion of the lens holder. A reflective and decorative treatment is provided on a front surface of the glare light protection shade. 
   When the upper opening portion is provided in the lens holder, light from the light source can pass through the upper opening portion and radiate diagonally upward and forward to cause glare. However, the glare light protection shade shields the light that can pass through the upper opening portion of the lens holder diagonally upward and forward. Accordingly, it prevents glare light from being generated. 
   Furthermore, the reflection-treated surface, which is the front surface of the glare light protection shade, reflects light that is guided into the interior of the projection-type light source unit via the upper opening portion of the lens holder forward towards the convex lens. Therefore, the rear part of the convex lens appears brighter, and thus the dimness of the convex lens is further reduced when the headlamp is not lit. Meanwhile, the decoration-treated surface, which is the front surface of the glare light protection shade, is illuminated brightly by the incoming light guided into the interior of the projection-type light source unit via the upper opening portion of the lens holder. Accordingly, a decorative pattern can be seen through the convex lens when the lamp is not lit. 
   A vehicular headlamp according to still another embodiment is structured such that the upper opening portion of the lens holder is covered with the front cover inclining rearward. 
   Because the front cover covering the upper opening portion of the lens holder is inclined rearward, an amount of incoming light entering the interior of the light source unit from the upper opening portion of the lens holder is increased. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  shows a front elevational view of a combination head lamp according to an embodiment of the present invention. 
       FIG. 2  shows a vertical sectional view of the headlamp (the sectional view taken along the line, II—II in  FIG. 1 ). 
       FIG. 3  shows an exploded perspective view of a reflector unit and an extension reflector of the headlamp. 
       FIG. 4  shows an exploded perspective view of a light source unit for generating a low beam, which is a portion of the headlamp. 
       FIG. 5  shows a vertical sectional view of a combination headlamp according to another embodiment of the present invention. 
       FIG. 6  shows a vertical sectional view of the headlamp (the sectional view taken along a line VI—VI in  FIG. 5 ). 
       FIG. 7  shows a perspective view of a reflector unit. 
       FIG. 8  shows an exploded perspective view of a light source unit for generating a low beam, which is a portion of the headlamp. 
       FIG. 9  shows a light distribution pattern of the low beam. 
       FIG. 10  shows a vertical sectional view of a conventional headlamp. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
     FIGS. 1 to 4  show a first embodiment of the present invention.  FIG. 1  shows a front elevational view of a vehicular combination headlamp, which is one embodiment of the present invention.  FIG. 2  shows a vertical sectional view of the headlamp (the sectional view taken along a line II—II in  FIG. 1 ).  FIG. 3  shows an exploded perspective view of a reflector unit and an extension reflector of the headlamp.  FIG. 4  shows an exploded perspective view of a light source unit for generating a low beam, which is a portion of the headlamp. 
   A container-shaped lamp body  10  has an opened front surface. A transparent front cover  11  is attached to the front surface opening portion of the lamp body  10  to define a light chamber S. In the light chamber S, a tiltable reflector unit  20  is provided with an aiming mechanism E constituted by an aiming fulcrum e 0  with a ball bearing structure and a pair of aiming points (a left-right aiming point e 1  and an up-down aiming point e 2 ). 
   The reflector unit  20  is an integrally molded body of synthetic resin (such as BMC resin) structured with a reflector  21  for generating a high beam at the undermost portion, a pseudo-reflector  22  with an attached projection-type light source unit U for generating a low beam thereabove, and a reflector  23  corresponding to a turn signal lamp at the uppermost portion. These reflectors are formed such that each reflector is consecutively set back in order from the reflector  21  at the undermost portion to the reflector  23  at the uppermost portion. An aluminum vapor deposition process is conducted on a surface of each of the reflectors. 
   The reflector  21  is provided with a substantially parabolic operative reflecting surface  21   a  extending along the right and left directions. Further, a bulb  24  for generating a high beam of the headlamp is attached to a bulb insertion hole  21   b  that is provided at a rear top portion of the reflector  21 . 
   A substantially parabolic pseudo-reflecting surface  22   a  extending along the right and left directions is provided on the pseudo-reflector  22 . Further, the light source unit U for generating a low beam of the headlamp is fixed by securing means, such as a screw and a concave-convex lance engagement, to an attachment frame  22   f  provided in a central portion of the reflector  22  in the horizontal direction. 
   The projection-type light source unit U is integrally structured by a reflector  30  that is opened forward and has a substantially ellipsoidal reflecting surface, a bulb  32  for generating a low beam of the headlamp that is disposed such that a filament is positioned in the vicinity of a first focal point of the reflector  30 , and a convex lens  36  that is disposed to the front of the reflector  30  via a cylindrical lens holder  34 . A light shielding shade  38   a  for forming a clear cut line of the low beam is vertically provided at a position that is in the vicinity of a second focal point of the reflector  30  and at a focal point of the convex lens  36 . The light shielding shade  38   a  is integrally formed with a shade member  37 , and the shade member  37  is integrated into the light source unit U by being sandwiched by the reflector  30  and the lens holder  34 . Reference numeral  36   a  refers to a metal fitting for securing the convex lens  36  to the lens holder  34 . 
   Moreover, a substantially parabolic reflecting surface  23   a  extending along the right and left directions is provided on the uppermost portion of the reflector  23 . Further, a bulb  26  for a turn signal lamp attached to the lamp body  10  is disposed such that it protrudes from an opening portion  23   b  provided at the rear top portion of the reflector  23  to the front of the substantially parabolic reflecting surface  23   a.    
   Further, tilting the reflector unit  20  by the aiming mechanism E allows adjustment of optical axes of the headlamp (an optical axis of the high beam and an optical axis of the low beam) in the up-down and right-left directions. Specifically, rotation of a left-right aiming screw e 11  allows the left-right aiming point e 1  to advance or retreat, and the reflector unit  20  to tilt around a vertically tilted axis Ly (an axis that passes through the aiming fulcrum e 0  and the up-down aiming point e 2 ). Further, rotation of an up-down aiming screw e 21  allows the up-down aiming point e 2  to advance or retreat, and the reflector unit  20  to tilt around a horizontally tilted axis Ly (an axis that passes through the aiming fulcrum e 0  and the left-right aiming point e 1 ). Accordingly, the optical axes of the headlamp can be adjusted in the up-down and right-left directions. 
   The front surface opening portion of the lamp body  10  opens widely from the diagonally upward and forward direction toward the side, and the transparent front cover  11  which is significantly inclined from the front toward the rear is attached. Thus, the entire reflector unit  20  in the light chamber S is covered with the transparent front cover  11  overhead. The extension reflector  40  on which an aluminum vapor deposition process is conducted similar to the surface treatment on the reflector unit  20  at a position surrounding the reflector unit  20  is disposed in the light chamber S. When the lamp is not lit, the interior of the light chamber S is seen through the transparent front cover  11  from a position forward of the vehicle, and the entire interior of the light chamber S appears bright with specular color. 
   Furthermore, the lens holder  34  that constitutes the projection-type light source unit U is provided with an upper opening portion  35   a  and a lower opening portion  35   b  for guiding outside light into the light source unit U. Accordingly, a portion behind the convex lens  36  appears brighter, thereby overcoming a conventional problem in which the convex lens  36  appears dim through the front cover when the lamp is not lit. Specifically, the extension reflector  40  and the reflector  23  are provided at the rear part of the upper opening portion  35   a  of the lens holder  35  of the light source unit U. Therefore, during the daytime when the light source of the headlamp is not lit, as shown in  FIG. 2 , light transmitted through the transparent front cover  11  that reaches the interior of the light chamber S is not shielded by the extension reflector  40  or the reflector  23 . Instead, it penetrates to the interior of the projection-type light source unit U, via the upper opening portion  35   a  of the lens holder as shown by arrow A, or via the lower opening portion  35   b  of the lens holder as shown by arrow B. Therefore, the interior of the projection-type light source unit U appears bright, and the convex lens  36  of the light source unit U which is seen through the transparent front cover  11  does not appear as dim as in the conventional cases. In particular, the entire interior of the light chamber S appears bright with specular color because of the reflector unit  20  and the extension reflector  40  disposed therearound. Further, because the dimness of the convex lens  36  of the light source unit U is reduced, the headlamp is visually improved. 
   Moreover, a glare light protection shade  38   b  for preventing glare, which is integrally formed with the shade member  37 , is vertically provided at a rear side edge portion of the upper opening portion  35   a  of the lens holder  34 . That is, the upper opening portion  35   a  in the lens holder  34  may allow direct light from the bulb  32  or light reflected by a bottom surface of an inner side of the reflector  30  to pass through the upper opening portion  35   a  and radiate diagonally upward and forward to cause glare. However, the glare light protection shade provided between the bulb  32  and the upper opening portion  35   a  of the lens holder  34  shields that light passing through the upper opening portion  35   a  of the lens holder  34  that is emitted diagonally upward and forward, thereby preventing glare. 
   Moreover, a tongue-shaped horizontal extending portion  38   c  is integrally formed with the shade member  37  and extends along the non-operative reflecting surface which is on the lower portion of the inner side of the reflector  30 . Heat-resistant black paint is applied on a top surface of the tongue-shaped horizontal extending portion  38   c  for reducing reflected light directed toward the upper opening portion  35   a  of the lens holder  34 , thereby suppressing glare. 
   An aluminum vapor deposition-treated surface is provided on the front surface of the glare light protection shade  38   b . Light is directed diagonally upward and forward to the upper opening portion  35   a  of the lens holder  34 , as shown by the arrow A in  FIG. 2 , reflected by the front surface of the glare light protection shade  38   b  (the aluminum vapor deposition-treated surface), then guided to the convex lens  36 . Therefore, the dimness of the convex lens  36  is further averted. 
   Note that the glare light protection shade  38   b , the light shielding shade  38   a , and the tongue-shaped horizontal extending portion  38   c  are integrally formed with the shade member  37  manufactured from aluminum die-cast. Although, it is possible to integrally form these shades  38   a ,  38   b  into the lens holder  34  or the reflector  30 , this involves complicated manufacturing equipment including a die structure for undercutting. Therefore, integrally forming the glare light protection shade  38   b  and the light shielding shade  38   a  into the shade member  37 , which is separate from the lens holder  34  and the reflector  30 , simplifies manufacturing of the lens holder  34  and the reflector  30 . 
   Moreover, heat-resistant black paint may be applied on the non-operative reflecting surface at the lower portion of the inner side of the reflector  30  without providing the tongue-shaped horizontal extending portion  38   c  in the shade member  37 . However, because it is difficult to apply a paint at a predetermined position within the reflector  30 , painting the inner side of the reflector  30  is avoided by integrally providing the tongue-shaped horizontal extending portion  38   c  in the shade member  37 , and applying heat-resistant black paint on the flattened tongue-shaped horizontal extending portion  38   c.    
     FIGS. 5 to 9  show a second embodiment of the present invention.  FIG. 5  shows a vertical sectional view of a vehicular combination headlamp.  FIG. 6  shows a vertical sectional view of the headlamp (the sectional view taken along a line VI—VI in  FIG. 5 ).  FIG. 7  shows a perspective view of the reflector unit.  FIG. 8  shows an exploded perspective view of the light source unit for generating a low beam, which is a portion of the headlamp.  FIG. 9  shows a light distribution pattern of the low beam. 
   In the aforementioned embodiment, the reflector  30 , which is a structural member of the light source unit U, is shaped like a container and forwardly opened, and the pseudo-reflector  22  is provided behind the light source unit U. However, a part of the right and left side walls of a reflector  30 A is cut out, and a substantially parabolic sub-reflector  22 B, which is integrally formed into a reflector unit  20 A and has an operative reflecting surface  22   b , is provided behind a light source unit U 1 . As shown by arrows in  FIG. 6 , a part of light from the bulb  32  is directed sideward via cutouts  31  then reflected and distributed by the su b-reflector  22 B to the front. Accordingly, visibility of the low beam is enhanced. 
   Specifically, the lens holder  34  is provided with upper and lower opening portions  35   a ,  35   b  similar to that of the aforementioned embodiment. Further, the lens holder  34  is provided with a skirt portion  39  that sets the amount of light emission sideward by defining the cutouts  31  of the reflector  30 . Therefore, as shown in  FIG. 9 , a light distribution by projection from the convex lens  36  of the light source unit U 1  creates a pattern PA having a clear cut line CL, and light is emitted sideward from the cutouts  31  of the reflector  30 A. Further, light distributed by the operative reflecting surface  22   b  of the reflector  22 B creates patterns PB 1 , PB 2  along the clear cut line CL, which are close to the center. Next, the patterns PA, PB 1 , PB 2  are synthesized to create a distribution pattern of the low beam. 
   Moreover, the front surface of the glare light protection shade  38   b  is provided with a decoration-treated surface  38   b   1  decorated with characters and patterns. The decoration-treated surface  38   b   1 , which is the front surface of the shade, is illuminated brightly by light guided to the interior of the projection-type light source unit U via the upper opening portion  35   a  of the lens holder  34 . Thus, when the lamp is not lit, the decorative pattern of the decoration-treated surface  38   b   1  is seen through a convex lens  36 . Therefore, the overall appearance can be innovative and original. 
   Other structures are the same as structures described in the aforementioned first embodiment. By denoting the same reference numerals, explanations are omitted to avoid redundancy. 
   Note that, in the aforementioned embodiments the reflector  23  for the turn signal lamp is integrally formed with the reflector unit  20  ( 20 A) which is tiltably supported by the aiming mechanism E. Alternatively, the reflector  23  may be structured separately from the reflector unit  20  ( 20 A) and secured to the lamp body  10 . In this case, the left-right aiming point e 1  and the aiming fulcrum e 0  that constitute the aiming mechanism E are at positions below the positions shown in  FIG. 1 . 
   Other implementations are within the scope of the following claims.