Patent Publication Number: US-11035541-B2

Title: Vehicular lamp unit and vehicular lamp

Description:
This application claims the priority benefit under 35 U.S.C. § 119 of Japanese Patent Application No. 2019-013542 filed on Jan. 29, 2019, which is hereby incorporated in its entirety by reference. 
     TECHNICAL FIELD 
     The presently disclosed subject matter relates to a vehicular lamp, and more particularly, to a vehicular lamp unit and a vehicular lamp capable of obtaining light distribution characteristics as designed. 
     BACKGROUND ART 
     Conventionally, in the field of vehicular lamps, there has been known a vehicular lamp comprising a substrate on which a light source is mounted, and a reflector in which a substrate fixing portion and a reflector main body are integrally molded, and having a structure in which the substrate is fixed to the reflector (the substrate fixing portion) by screwing a screw inserted into a through hole formed in the substrate to a boss portion (a thick portion protruding from the substrate fixing portion, or a screw boss) provided in the substrate fixing portion (for example, refer to Japanese Patent Application Laid-Open No. 2018-137125 A (FIG. 2 and the like)). 
     However, the present inventor has investigated and found that the above-mentioned conventional vehicular lamp cannot obtain light distribution characteristics as designed. This is considered to be caused by deformation of the reflector (reflective surface) due to stress generated by deformation of the boss portion due to screwing of the screw because the rigidity of the reflector is lower than that of the substrate. 
     SUMMARY 
     The presently disclosed subject matter was devised in view of these and other problems and features in association with the conventional art. According to an aspect of the presently disclosed subject matter, there can be provided a vehicular lamp unit and a vehicular lamp capable of obtaining light distribution characteristics as designed. 
     According to another aspect of the presently disclosed subject matter, a vehicular lamp unit includes: a substrate on which a light source is mounted; a reflector including a substrate fixing portion and a reflector main body that are integrally molded; and an engaging member. Herein, the substrate includes a first through hole formed therein, into which the engaging member is inserted; the substrate fixing portion includes an engaged portion with which the engaging member is engaged; the reflector main body includes a base end portion fixed to the substrate fixing portion and a reflective surface configured to reflect light emitted from the light source; the substrate is fixed to the substrate fixing portion in a state in which the substrate is held between the engaging member and the substrate fixing portion by engaging the engaging member, which has been inserted into the first through hole, into the engaged portion; and the substrate fixing portion includes at least one second through hole formed therein between the base end portion of the reflector main body and the engaged portion. 
     Herein, the engaging member may preferably be a screw and the engaged portion may preferably be a boss portion into which the screw is to be screwed. Further, it is preferable that, by screwing the screw into the boss portion, the substrate be fixed to the substrate fixing portion in a state in which the substrate is held between the head portion of the screw and the substrate fixing portion. 
     According to this aspect, it is possible to provide a vehicular lamp unit capable of obtaining light distribution characteristics as designed. 
     This is because the through hole is formed in the substrate fixing portion in a position between the base end portion of the reflector main body and the boss portion. 
     As a result, even when the substrate is fixed to the substrate fixing portion by screwing the screw, which has been inserted into the through hole formed in the substrate, into the boss portion provided in the substrate fixing portion, deformation of the reflector (reflective surface) is suppressed, so that light distribution characteristics as designed can be obtained. 
     In the aforementioned invention, a preferable mode is configured such that the rigidity of the reflector is lower than that of the substrate. 
     Further, in the aforementioned invention, a preferable mode is configured to further include a heat dissipation member and such that the heat dissipation member includes a third through hole formed therein into which the screw is inserted; the substrate is disposed between the heat dissipation member and the substrate fixing portion; and the substrate and the heat dissipation member are fixed to the substrate fixing portion in a state of being held between the head portion of the screw and the substrate fixing portion by screwing the screw, which has been inserted into the first through hole and the third through hole, into the boss portion. 
     In the aforementioned invention, a preferable mode is configured such that the rigidity of the reflector is lower than those of the substrate and the heat dissipation member. 
     In the aforementioned invention, a preferable mode is configured such that the heat dissipation member includes a heat dissipation fin. 
     Further, in the aforementioned invention, an alternative preferable mode is configured such that the heat dissipation member does not include a heat dissipation fin. 
     In the aforementioned invention, a preferable mode is configured such that the substrate fixing portion includes a positioning convex portion, the positioning convex portion is provided at a plurality of positions with the boss portion located therebetween, and the substrate is fixed to the substrate fixing portion in a state in which the positioning convex portion abuts against the substrate so that a gap is formed between the substrate and the substrate fixing portion. 
     In the aforementioned invention, a preferable mode is configured such that the substrate fixing portion includes a reinforcing rib portion that is provided between the second through hole and the boss portion. 
     In the aforementioned invention, a preferable mode is configured such that the reinforcing rib portion is provided along the second through hole. 
     According to still another aspect of the presently disclosed subject matter, a vehicular lamp includes a plurality of the vehicular lamp units according to any one of the foregoing aspect and modes. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       These and other characteristics, features, and advantages of the presently disclosed subject matter will become clear from the following description with reference to the accompanying drawings, wherein: 
         FIG. 1  is an exploded perspective view of a vehicular lamp  10  made in accordance with presently disclosed subject matter, as viewed from the front; 
         FIG. 2  is an exploded perspective view of the vehicular lamp  10  as viewed from the rear; 
         FIG. 3  is a top view of a vehicular lamp unit  10 A of the vehicular lamp  10  while omitting a substrate  20  and a heat dissipation member  30 ; 
         FIG. 4A  is a cross-sectional view taken along line A-A of  FIG. 3 , and  FIG. 4B  is a cross-sectional view taken along line B-B of  FIG. 3 ; 
         FIGS. 5A and 5B  are each a simplified diagram, which corresponds to a vertical cross-sectional view, for illustrating the action of a positioning convex portion  41   e;    
         FIG. 6  is a diagram for illustrating that light reflected from a reflective surface  42   b  is irradiated in a direction D 2  different from a target direction D 1 ; 
         FIGS. 7A, 7B, and 7C  are each a diagram illustrating an example or a modified example of a through hole H 6 ; 
         FIG. 8  is a diagram illustrating a modified example of the through hole H 6 ; 
         FIG. 9  is a diagram illustrating an example of a reinforcing rib  41   h;    
         FIG. 10  is a diagram illustrating a modified example of a heat dissipation member  30 ; 
         FIG. 11  is a diagram illustrating a modified example of the vehicular lamp unit  10 A; and 
         FIG. 12  is a diagram illustrating a modified example of the vehicular lamp unit  10 A. 
     
    
    
     DESCRIPTION OF EXEMPLARY EMBODIMENTS 
     A description will now be made below to vehicular lamps  10  of the presently disclosed subject matter with reference to the accompanying drawings in accordance with exemplary embodiments. It should be noted that components corresponding to each other in the respective drawings are denoted by the same reference numerals, and repetitive descriptions thereof will be omitted. 
       FIG. 1  is an exploded perspective view of a vehicular lamp  10  as viewed from the front,  FIG. 2  is an exploded perspective view of the vehicular lamp  10  as viewed from the rear,  FIG. 3  is a top view of a vehicular lamp unit  10 A of the vehicular lamp  10  while omitting a substrate  20  and a heat dissipation member  30 ,  FIG. 4A  is a cross-sectional view taken along line A-A of  FIG. 3 , and  FIG. 4B  is a cross-sectional view taken along line B-B of  FIG. 3 . 
     The vehicular lamp  10  shown in  FIGS. 1 to 4B  is a vehicular headlamp capable of forming a light distribution pattern for a low beam or a light distribution pattern for a high beam, and is to be mounted on left and right sides of a front end portion of a vehicle (not shown). The light distribution pattern for a low beam or the light distribution pattern for a high beam is assumed to be formed on an imaginary vertical screen facing the front surface of the vehicle, which is assumed to be disposed about 25 m forward from the front surface of the vehicle. 
     Since the vehicular lamps  10  mounted on both the left and right sides have a symmetrical configuration, the vehicular lamp  10  mounted on the right side (right side toward the front of the vehicle) of the front end portion of the vehicle (not shown) will be described below as a representative. Hereinafter, for convenience of description, the XYZ axes will be defined. The X-axis extends in the front-rear direction of the vehicle, the Y-axis extends in the vehicle width direction, and the Z-axis extends in the vertical direction. 
     As shown in  FIG. 1 , the vehicular lamp  10  can include three vehicular lamp units  10 A,  10 B, and  10 C. Hereinafter, the vehicular lamp units  10 A,  10 B, and  10 C are simply referred to as lamp units  10 A,  10 B, and  10 C. The lamp units  10 A and  10 B are each a lamp unit for a low beam. On the other hand, the lamp unit  10 C is a lamp unit for a high beam. Since the lamp units  10 A and  10 B for a low beam and the lamp unit  10 C for a high beam have the same configuration except for the different reflective surface, the lamp unit  10 A for a low beam will be described below as a representative. 
     As shown in  FIGS. 4A and 4B , the lamp unit  10 A includes a substrate  20  on which a light source  21  is mounted, a heat dissipation member  30 , a reflector  40 , and a screw  50 . The lamp unit  10 A is disposed in a lamp chamber constituted by an outer lens and a housing, which are not illustrated, and is fixed to the housing or the like. 
     The substrate  20  is a substrate made of metal such as aluminum and includes an upper surface  20   a  and an opposite lower surface  20   b.    
     Specifically, the light source  21  is mounted on the lower surface  20   b  of the substrate  20 , and emits light downward. The light source  21  is, for example, a semiconductor light emitting element such as an LED that emits white light. 
     A through hole H 1  (an example of the first through hole according to the presently disclosed subject matter) into which a boss portion  41   c  (an example of the engaged portion according to the presently disclosed subject matter) provided in the reflector  40  (and a screw  50  (an example of the engaging member according to the presently disclosed subject matter)) is to be inserted and a through hole H 2  into which a positioning pin  41   d  (see  FIG. 4B ) provided in the reflector  40  is to be inserted are formed in the substrate  20 . Each of the through holes H 1  and H 2  penetrates the substrate  20  from the upper surface  20   a  to the lower surface  20   b  thereof. 
     The heat dissipation member  30  is a member (heat sink) configured to radiate heat generated by the light source  21  for cooling, and includes a base portion  31  and heat dissipation fins  32 . The heat dissipation member  30  is a metal member such as aluminum die casting, for example. 
     The base portion  31  includes an upper surface  31   a  and an opposite lower surface  31   b . The heat dissipation fins  32  are provided on the upper surface  31   a  of the base portion  31 . 
     A through hole H 3  (an example of the third through hole according to the presently disclosed subject matter) into which the boss portion  41   c  provided in the reflector  40  (and the screw  50 ) is to be inserted and a through hole H 4  into which the positioning pin  41   d  (see  FIG. 4B ) provided in the reflector  40  is to be inserted are formed in the heat dissipation member  30  (base portion  31 ). Each of the through holes H 3  and H 4  penetrates the base portion  31  from the upper surface  31   a  to the lower surface  31   b  thereof. A notch  32   a  (see  FIG. 1 ) is formed in a part of the heat dissipation fins  32  so that the boss portion  41   c  inserted into the through hole H 3  does not interfere therewith. 
     The reflector  40  includes a substrate fixing portion  41  (ceiling surface) and a reflector main body  42 . The reflector  40  is made of a synthetic resin such as a polycarbonate resin and integrally molded by injection molding of a synthetic resin such as a polycarbonate resin. 
     The substrate fixing portion  41  includes an upper surface  41   a  and an opposite lower surface  41   b . The upper surface  41   a  is a plane substantially parallel to the XY plane. 
     The reflector main body  42  includes a base end portion  42   a  continued to the substrate fixing portion  41  (lower surface  41   b ) and a reflective surface  42   b  configured to reflect light emitted from the light source  21 . 
     The reflective surface  42   b  is formed by performing metal vapor deposition such as aluminum vapor deposition on the front surface of the reflector main body  42 . When the reflector  40  is made of a polycarbonate resin, there is an advantage that metal can be directly deposited on the reflector  40  without applying an undercoat. 
     The reflective surface  42   b  is a reflective surface based on a paraboloid, and includes a plurality of rectangular reflective regions (not shown) partitioned in a lattice shape by a horizontal plane and a vertical plane (so-called multi-reflector). The light source  21  is disposed in the vicinity of the focal point of the reflective surface  42   b . The surface shape of each reflective region is designed so that light from the light source  21  reflected by the reflective region and irradiated forward forms a light distribution pattern for a low beam. The symbol AX in  FIG. 4A  is an optical axis of the lamp unit  10 A, passes through the focal point of the reflective surface  42   b , and extends in the X direction. 
     As shown in  FIG. 3 , the substrate fixing portion  41  includes, on its upper surface  41   a , the boss portion  41   c  or a screw boss, the positioning pin  41   d , and a positioning convex portion  41   e.    
     The boss portion  41   c  is provided on the upper surface  41   a  of the substrate fixing portion  41  rearward of the base end portion  42   a  of the reflector main body  42  (upward in  FIG. 3 ). The boss portion  41   c  is formed in a truncated conical shape having a diameter decreasing upward (see  FIG. 1  and  FIG. 4A ). A screw hole  41   k  into which the screw  50  is to be screwed is formed in the boss portion  41   c  (see  FIG. 4A ). The screw hole  41   k  extends in the Z direction from the distal end surface of the boss portion  41   c.    
     The positioning pins  41   d  are provided at appropriate positions on the upper surface  41   a  of the substrate fixing portion  41 , for example, at two positions in  FIG. 3 . 
     The positioning convex portions  41   e  are provided at a plurality of positions of the upper surface  41   a  of the substrate fixing portion  41  with the boss portion  41   c  located therebetween. For example, the positioning convex portions  41   e  are provided at positions (two positions in  FIG. 3  are illustrated) rearward (upward in  FIG. 3 ) of the boss portion  41   c  and at positions (two positions in  FIG. 3  are illustrated) forward (downward in  FIG. 3 ) of the boss portion  41 C on the upper surface  41   a  of the substrate fixing portion  41 , respectively. The distal end surface of the positioning convex portion  41   e  is a flat plane substantially parallel to the XY plane. The positioning convex portions  41   e  may be omitted in some cases. 
       FIGS. 5A and 5B  are each a simplified diagram, which corresponds to a vertical cross-sectional view, for illustrating the action of the positioning convex portion  41   e . For convenience of explanation, the boss portion  41   c , the screw  50 , and the like are omitted in  FIG. 5 . For convenience of explanation, in  FIG. 5 , the substrate  20 , the heat dissipation member  30 , and the reflector  40  including the substrate fixing portion  41  are illustrated in a simplified manner. 
     As shown in  FIG. 5A , when the positioning convex portion  41   e  abuts against the substrate  20  (against the lower surface  20   b  thereof), a gap S is formed between the lower surface  20   b  of the substrate  20  and the upper surface  41   a  of the substrate fixing portion  41  of the reflector  40 . 
     The length L of the positioning convex portion  41   e  in the Z direction may be any length as long as a gap S is formed between the lower surface  20   b  of the substrate  20  and the upper surface  41   a  of the substrate fixing portion  41  of the reflector  40 , and is, for example, several millimeters. 
     As shown in  FIGS. 3 to 4B , a through hole H 5  is formed in the substrate fixing portion  41  to allow the light from the light source  21  mounted on the substrate  20  to pass therethrough. The through hole H 5  penetrates the substrate fixing portion  41  from the upper surface  41   a  to the lower surface  41   b  thereof. The through hole H 5  is formed forward of the base end portion  42   a  of the reflector main body  42 . 
     The substrate  20  having the above-described configuration is disposed with its lower surface  20   b  facing the upper surface  41   a  of the substrate fixing portion  41  of the reflector  40 , as shown in  FIGS. 4A and 4B . 
     At this time, the boss portion  41   c  provided in the reflector  40  is inserted into the through hole H 1  formed in the substrate  20 . At the same time, the positioning pin  41   d  provided in the reflector  40  is inserted into the through hole H 2  formed in the substrate  20 . As a result, the substrate  20  is positioned in the XY direction. 
     Further, as shown in  FIG. 5A , the positioning convex portion  41   e  provided in the reflector  40  abuts against the lower surface  20   b  of the substrate  20  at the tip surface thereof. As a result, the substrate  20  is positioned in the Z direction. 
     At this time, since the gap S is formed between the lower surface  20   b  of the substrate  20  and the upper surface  41   a  of the substrate fixing portion  41  of the reflector  40 , the lower surface  20   b  of the substrate  20  and the upper surface  41   a  of the substrate fixing portion  41  of the reflector  40  do not come into contact with each other. Thus, regardless of the state of the upper surface  41   a  of the substrate fixing portion  41  of the reflector  40 , for example, even when the upper surface  41   a  of the substrate fixing portion  41  of the reflector  40  is not flat but distorted, the substrate  20  can be accurately positioned in the Z direction. 
     As a result of the positioning of the substrate  20  in the XYZ directions as described above, the light source  21  is accurately disposed in the vicinity of the focal point of the reflector  40 . 
     On the other hand, the heat dissipation member  30  having the above-described configuration is disposed in a state in which the lower surface  31   b  is in contact with the upper surface  20   a  of the substrate  20 , as shown in  FIGS. 4A and 4B . 
     At this time, the boss portion  41   c  inserted into the through hole H 1  formed in the substrate  20  is inserted into the through hole H 3  formed in the heat dissipation member  30  (see  FIG. 4A ). At the same time, the positioning pin  41   d  inserted into the through hole H 2  formed in the substrate  20  is inserted into the through hole H 4  formed in the heat dissipation member  30  (see  FIG. 4B ). As a result, the heat dissipation member  30  is positioned in the XY direction. 
     Although not shown, it is preferable to dispose a heat conduction member between the upper surface  20   a  of the substrate  20  and the lower surface  31   b  of the heat dissipation member  30  from the viewpoint of enhancing heat conductivity between the substrate  20  (light source  21 ) and the heat dissipation member  30 . The heat conduction member is, for example, a thermal grease or a heat conduction sheet. 
     Then, the screw  50  is screwed into the boss portion  41   c  inserted into the through holes H 1  formed in the substrate  20  and the through holes H 3  formed in the heat dissipation member  30  as described above (for example, screwed clockwise), whereby the substrate  20  and the heat dissipation member  30  are fixed to the substrate fixing portion  41  in a state of being held between the head portion  51  of the screw  50  and the positioning convex portion  41   e  of the substrate fixing portion  41  (see  FIG. 4A ). 
     In the lamp unit  10 A having the above configuration, when the light source  21  is turned on, light from the light source  21  passes through the through hole H 5  and is reflected by the reflective surface  42   b , and then is irradiated forward to form a light distribution pattern for a low beam. 
       FIG. 6  is a diagram for illustrating that the reflected light from the reflective surface  42   b  is irradiated in a direction D 2  different from a target direction D 1 . 
     As a result of examination by the present inventor, it has been found that in a lamp unit having the similar configuration described heretofore without a through hole H 6 , the reflector  40  (the reflective surface  42   b ) is distorted (deformed from the designed shape) as illustrated in  FIG. 6 , and as a result, the reflected light from the reflective surface  42   b  is irradiated in the direction D 2  different from the target direction D 1 , and thus the light distribution characteristic as designed cannot be obtained. The symbol ε in  FIG. 6  represents the distortion amount. 
     The reason why the reflective surface  42   b  of the reflector  40  is distorted can be considered as follows. 
     That is, since the rigidity of the reflector  40  made of a synthetic resin is lower than that of the substrate  20  and the heat dissipation member  30  both made of metal, the boss portion  41   c  is compressed and deformed in the Z direction in accordance with the screwing of the screw  50 . The substrate  20  and the heat dissipation member  30  are relatively firmly held between the head portion  51  of the screw  50  and the substrate fixing portion  41  (positioning convex portion  41   e ) by the repulsive force (or restoring force) of the deformed boss portion  41   c.    
     At this time, a stress (hereinafter, referred to as a first stress) generated by the repulsive force of the boss portion  41   c  acts on the reflector  40  (reflective surface  42   b ). As a result, it is considered that the reflector  40  (the reflective surface  42   b ) is distorted. 
     The following can also be considered. 
     That is, when the boss portion  41   c  deforms as described above, the upward force F in the Z direction acts on the substrate fixing portion  41  (see  FIG. 5A ). At this time, since the gap S is formed between the lower surface  20   b  of the substrate  20  and the upper surface  41   a  of the substrate fixing portion  41  of the reflector  40 , the substrate fixing portion  41  bends upward in a convex arc shape with the positioning convex portion  41   e  as a fulcrum by the force F upward in the Z direction (see a dotted line indicated by reference numeral  41 A in  FIG. 5A ). A stress (hereinafter, referred to as a second stress) generated by the deflection of the substrate fixing portion  41  acts on the reflector  40  (the reflective surface  42   b ). As a result, it is considered that the reflector  40  (the reflective surface  42   b ) is distorted. 
     It is also considered that both of the first stress and the second stress act on the reflector  40  (the reflective surface  42   b ), and as a result, the reflector  40  (the reflective surface  42   b ) is distorted. 
     The present inventor has intensively investigated in order to obtain light distribution characteristics as designed. As a result, as shown in  FIG. 3  and  FIG. 4B , the present inventor has found that the light distribution characteristic as designed can be obtained by forming a through hole H 6  (an example of the second through hole according to the presently disclosed subject matter) in a position between the base end portion  42   a  of the reflector main body  42  and the boss portion  41   c  of the substrate fixing portion  41 . 
     This is considered to be because, when the through-hole H 6  is formed, at least one of the first stress and the second stress acts on only a rear portion  41   f  (see  FIG. 5B ) of the substrate fixing portion  41  with the through hole H 6  as a boundary, so that only the rear portion  41   f  bends and a front portion  41   g  does not bend, as indicated by a dotted line  41 Af in  FIG. 5B . 
       FIGS. 7A to 8  show modified examples of the through hole H 6 . 
     The through hole H 6  penetrates the substrate fixing portion  41  from the upper surface  41   a  to the lower surface  41   b . The through hole H 6  may have any shape as long as it is formed in a position between the base end portion  42   a  of the reflector main body  42  and the boss portion  41   c  (see  FIG. 3  and  FIG. 4B ). 
     For example, the through hole H 6  may have a shape curved along the base end portion  42   a  of the reflector main body  42  in a top view (see  FIGS. 3 and 8 ) or may have a shape linearly extending in the Y direction (see  FIGS. 7A to 7C ). In addition, the through hole H 6  may be separated by the connection portion  41   j  halfway (see  FIG. 3  and  FIG. 7A ) or may not be separated (see  FIG. 7B ,  FIG. 7C , and  FIG. 8 ). 
     In addition, for example, a plurality of through holes H 6  may be provided (see  FIG. 3  and  FIG. 7A ) or a single through hole H 6  may be provided (see  FIG. 7B ,  FIG. 7C , and  FIG. 8 ). 
     The through hole H 6  is desirably set as long as possible in the Y direction (see  FIGS. 3 and 7C ), but may be set short (see  FIG. 7B ). 
     In order to suppress deformation of the rear portion  41   f  by at least one of the first stress and the second stress acting on the rear portion  41   f , it is desirable to provide a reinforcing rib  41   h  in the rear portion  41   f  as shown in  FIGS. 8 and 9 . The reinforcing rib  41   h  may preferably be provided between the through hole H 6  and the boss portion  41   c , and in particular, may preferably be provided in a curved state along the through hole H 6  like that in  FIG. 8 . 
     As described above, according to the present embodiment, it is possible to provide the vehicular lamp unit  10 A and the vehicular lamp  10  capable of obtaining the light distribution characteristics as designed. 
     This is because the through hole H 6  is formed in a position between the base end portion  42   a  of the reflector main body  42  and the boss portion  41   c  of the substrate fixing portion  41 . 
     As a result, even when the substrate  20  is fixed to the reflector  40  (substrate fixing portion  41 ) by screwing the screw  50 , inserted into the through hole H 1  formed in the substrate  20 , into the boss portion  41   c  provided in the reflector  40  (substrate fixing portion  41 ), deformation of the reflector  40  (reflective surface  42   b ) is suppressed, so that light distribution characteristics as designed can be obtained. 
     In the foregoing embodiment, a screw is exemplified as the engaging member in the presently disclosed subject matter. In addition, a boss portion provided in the reflector is illustrated as an engaged portion to be engaged with the engaging member. The presently disclosed subject matter is not limited to these, and may include members configured to engage and fix the reflector with and to the substrate in the Z direction (thus causing compression deformation of the reflector). For example, in addition to screwing the screw into the boss portion, methods may be used in which an engaging member such as a grommet or a rivet may be inserted into an engaged portion such as an engaged hole formed in a boss or directly in a reflector and fixed by compression or caulking. 
     Next, a modified example will be described. 
     In the aforementioned embodiment, an example in which the vehicular lamp unit according to the presently disclosed subject matter is applied to a vehicular headlamp (a lamp unit for a low beam and a lamp unit for a high beam) has been described, but the presently disclosed subject matter is not limited thereto. For example, the vehicular lamp unit according to the presently disclosed subject matter may be applied to various vehicular lamps other than the vehicular headlamp, for example, a vehicular signal lamp. 
       FIG. 10  is a diagram illustrating a modified example of the heat dissipation member  30 . 
     In the aforementioned embodiment, an example in which the heat dissipation member  30  including the heat dissipation fins  32  is used has been described, but the presently disclosed subject matter is not limited thereto. For example, as illustrated in  FIG. 10 , a heat dissipation member  30  that does not include any heat dissipation fins  32  may be used. 
       FIG. 11  is a diagram illustrating a modified example of the vehicular lamp unit  10 A. 
     In the aforementioned embodiment, an example in which the heat dissipation member  30  is used has been described, but the presently disclosed subject matter is not limited thereto. For example, as illustrated in  FIG. 11 , the heat dissipation member  30  may be omitted. 
     Also in this case, since the rigidity of the reflector  40  made of a synthetic resin is lower than that of the substrate  20  made of metal, the boss portion  41   c  is compressed and deformed in the Z direction in accordance with the screwing of the screw  50 . The substrate  20  is held between the head portion  51  of the screw  50  and the substrate fixing portion  41  (positioning convex portion  41   e ) by the repulsive force (or restoring force) of the deformed boss portion  41   c.    
     According to the present modified example, similarly to the aforementioned embodiment, the formation of the through hole H 6  in a position between the base end portion  42   a  of the reflector main body  42  and the boss portion  41   c  of the substrate fixing portion  41  can achieve the light distribution characteristic as designed. 
       FIG. 12  is a diagram illustrating a modified example of the vehicular lamp unit  10 A. 
     The lamp unit  10 A may be disposed in a state of being rotated by a predetermined angle about the optical axis AX. For example, as shown in  FIG. 12 , the lamp unit  10 A may be disposed in a state of being rotated by 90 degrees about the optical axis AX. Further, for example, although not illustrated, the lamp unit  10 A may be disposed in a state of being rotated by 45 degrees about the optical axis AX. 
     Respective numerical values shown in the above embodiment and modified examples is merely an example, and it is a matter of course that an appropriate numerical value different from this can be used. 
     It will be apparent to those skilled in the art that various modifications and variations can be made in the presently disclosed subject matter without departing from the spirit or scope of the presently disclosed subject matter. Thus, it is intended that the presently disclosed subject matter cover the modifications and variations of the presently disclosed subject matter provided they come within the scope of the appended claims and their equivalents. All related art references described above are hereby incorporated in their entirety by reference.