Vehicle lighting device

A vehicle lighting device with a lamp compartment having a light source unit disposed therein. The light source unit includes a light emitting device as a light source and a projection lens as a light distribution control member for distributing light. A face bearing portion at a distal end of a lens mounting portion of the light emitting device corresponds to a rear surface of a collar portion disposed along an outer circumference of the projection lens. Complimentary extending projections and stepped portions on the collar portion and lens mounting portion are ultrasonically welded together, and burrs formed during the welding process are prevented from protruding toward the optical axis by an erect wall of the stepped portion.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to Japanese Patent Application No. 2005-354580, filed Dec. 8, 2005, in the Japanese Patent Office. The priority application is incorporated by reference in its entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a vehicle lighting device in which a light source unit including at least a light emitting device as a light source and a projection lens as a light distributing member for distributing light from the light source forward are provided in a lamp compartment. More particularly, the present invention relates to a vehicle lighting device that forms a predetermined light distribution pattern by combining light beam patterns emitted from a plurality of light source units provided in the lamp compartment.

2. Description of the Background Art

In general, as an example, a vehicle headlamp is configured to form a low beam light distribution pattern having a cut-off line along an upper edge of the pattern, whereby a forward visibility for the driver of the subject vehicle is secured as much as possible while suppressing the generation of glare to the driver of an oncoming vehicle or the like.

The following discussion refers to two background vehicle headlamps disclosed in JP-A-2005-166588 (hereinafter “Patent Document No. 1”) and JP-A-2000-100214 (hereinafter “Patent Document No. 2”).

In recent years, there has been a vigorous tendency to develop vehicle headlamps which use light emitting devices as light sources. Patent Document No. 1 discloses a vehicle headlamp in which a plurality of light source units using light emitting devices as their light sources are provided in a lamp compartment and a low beam light distribution pattern is formed by overlapping respective light beam patterns formed by the light source units so provided.

As is shown inFIG. 12, each light source unit is made up of a light distribution control member and a light emitting device2as a light source. The light distribution control member includes a reflector7, a shade6for forming a cut-off line, and a projection lens4. The light source unit is mounted integrally on a front side of a bracket1, which makes up a unit support member.

Since light of the light emitting device2used as the light source has little heat, the projection lens4and the cut-off line forming shade6can be made from a synthetic resin with a view to reducing the weight thereof. The bracket1, which is the unit support member on which the light emitting device2is mounted, can be made of a die-cast metallic product having a good heat conductive property with a view to suppressing the increase in temperature of the light emitting device2, which could lead to the reduction in the life of the light emitting device2. High temperatures can cause the light emitting device to eventually experience a reduction in light flux and/or change in the color of light emitted from the light emitting device2.

An acrylic resin lens4and a polycarbonate resin shade6may be integrated into a single unit by insert molding. The resin shade6and the metallic bracket1may be fastened together with a metallic fastening screw8. A bracket7aof the reflector7and a bracket of the shade6may also be fastened together with the fastening screw8.

Although it does not disclose a projection type lamp in which light is projected and distributed by a projection lens as disclosed in Patent Document No. 1, Patent Document No. 2 discloses a reflection type headlamp which forms a predetermined light distribution pattern by reflecting light from a light source by a reflector, and this reflection type headlamp has a lamp construction in which a resin outer lens that is to be assembled to a front opening in a resin housing is fixed to the resin housing by means of ultrasonic welding.

A vehicle headlamp, such as shown in Patent Document No. 1 above, in which a low beam light distribution pattern is formed by overlapping light beam patterns formed by a plurality of light source units, requires positional accuracy between the resin lens4and shade6which are the light distribution control members. Such a vehicle headlamp also requires that the positional accuracy of the light distribution control members (i.e., the lens4and the shade6) relative to the bracket1be maintained. Namely, respective optical axes of the light source units need to be aligned. Due to this, a construction is adopted in which a plurality of positioning projections6bare provided on an abutment surface of the shade6against the bracket1in order to secure a positional accuracy of the light distribution control members (i.e., the lens4and the shade6) relative to the bracket1.

In Patent Document No. 1, however, the resin lens4and resin shade6are integrated into the single unit by means of insert molding. As a result, a mold for integrally molding both the lens4and the shade6is complex, and large-sized molding equipment becomes necessary, resulting in an increase in production cost.

To cope with this, the inventor considered that as with Patent Document No. 2, in the event that the resin projection lens4and the resin shade6are formed into an integrated unit by welding such as ultrasonic welding, there is no need for a complex mold for integrating both the lens4and the shade6into a single unit, nor is large-sized molding equipment necessary. Therefore, the increase in production cost is suppressed.

However, in the event that the resin lens4and the resin shade6are integrated into the single unit by means of welding, burrs produced at the weld between the lens and the shade protrude (i.e., are exposed) towards an optical axis side of the lens4, whereby the light distribution is adversely affected or the burrs become visible through the lens4, such that the appearance of the headlamp when not lit is deteriorated.

The inventor next considered a construction in which a projection is formed on a rear surface side of the resin lens4, while a stepped portion is formed on an outer circumference of a distal end portion of the resin shade6as a lens abutment portion so that the projection on the lens4is brought into longitudinal engagement therewith. The projection on the lens4and the stepped portion on the shade6are welded together so that the lens4and the shade6are integrated. An inner circumferential side of the stepped portion of the shade6functions as a barrier to prevent fused resin produced at the time of welding from flowing out towards the optical axis side of the lens4. In other words, the fused resin does not protrude towards the optical axis side of the lens4to thereby avoid the protrusion of burrs. The inventor produced this construction as an experiment to study the effectiveness thereof and confirmed that the construction was effective, leading to the filing of the instant application.

SUMMARY OF THE INVENTION

The invention in the present application was made in view of the problems in the related art described above and based on the knowledge of the inventor so obtained, and an object thereof is to provide an automotive lamp which includes a light source unit which enables a simple and accurate integration of a resin lens with a resin lens mounting portion, which are both light distribution control members, by means of welding, in place of the insert molding which has been used conventionally, and which is free from a defect in which burrs produced at the weld protrude towards the optical axis side of the lens.

According to a first aspect of the invention, there is provided a vehicle lighting device having provided in a lamp compartment a light source unit including at least a light emitting device as a light source and a projection lens as a light distribution control member for distributing light from the light source forwards, the projection lens, which is made from a resin, being mounted on a lens mounting portion made from a resin which extends forwards from the light emitting device. A face bearing portion may be formed at a distal end of the lens mounting portion so as to correspond to a rear surface of a collar portion formed along an outer circumference of the projection lens. A plurality of extending projections may be provided on an outer circumferential side of either of the rear surface of the collar portion and the face bearing portion so as to be welded to be fixed to the other, while a plurality of stepped portions may be formed on an outer circumferential side of the other so as not only to be brought into axial engagement with the plurality of extending projections with an optical axis of the projection lens aligned substantially with a longitudinal axis of the lens mounting portion, but also to make up erect walls which lie along insides of the extending projections. The extending projections and the stepped portions may be welded together so that the rear surface of the collar portion and the face bearing portion are brought into longitudinal abutment with each other.

Equipment for welding the extending projections and stepped portions together so that the collar portion of the projection lens and the face bearing portion of the lens mounting portion are brought into axial (longitudinal) abutment with each other becomes simple in construction, small in size and hence inexpensive in cost, compared to the complex and large-sized mold equipment for insert molding the projection lens and the lens mounting portion.

From the longitudinal abutment of the rear surface of the collar portion formed along the outer circumference of the projection lens with the face bearing portion formed at the distal end of the lens mounting portion, the optical axis of the projection lens and the longitudinal axis of the lens mounting portion are positioned parallel to each other.

Secondarily, the focal point of the projection lens and a predetermined position of the lens mounting portion are aligned with each other in the longitudinal direction, whereby a desired light distribution can be obtained by the light source unit.

Note that although the focal point of the projection lens and the predetermined position of the lens mounting portion can be aligned substantially with each other vertically and horizontally by bringing the plurality of extending projections on the projection lens (or the lens mounting portion) side into axial engagement with the corresponding stepped portions on the lens mounting portion (or the projection lens) side, they cannot necessarily be aligned with each other accurately. However, in forming a desired light distribution by the light source unit, there is no serious problem even though the focal point of the projection lens and the predetermined position of the lens mounting portion side deviate from each other somewhat vertically and/or horizontally, provided at least that the optical axis of the projection lens and the longitudinal axis are parallel, and the focal point of the projection lens and the predetermined position on the lens mounting portion side are aligned in the longitudinal direction. However, since it is better that the focal point of the projection lens and the predetermined position on the lens mounting portion side are aligned vertically and horizontally, the plurality of extending projections and the corresponding stepped portions are disposed diametrically across the optical axis of the lens, whereby the focal point of the projection lens and the predetermined position on the lens mounting portion side can be aligned substantially with each other vertically and horizontally more assuredly.

In addition, the erect wall formed on the stepped portion on the lens mounting portion (or the projection lens) extends along the inside of the extending projection on the lens (or the lens mounting portion) and functions as a barrier which prevents resin fused when the extending projection is welded to the stepped portion from flowing towards the optical axis side of the projection lens, so as to prevent the protrusion of burrs produced at the weld between the extending projection and the stepped portion towards the optical axis of the projection lens, thereby avoiding defects such as burrs at the weld. Consequently, there is no chance that burrs at the weld will adversely affect the light distribution or become visible through the projection lens.

According to a second aspect of the invention, a vehicle lighting device as set forth in the first aspect of the invention is provided, wherein the extending projections and the stepped portions are both disposed at substantially equal intervals in a circumferential direction of the projection lens. Since the projection lens and the lens mounting portion are welded and fixed to each other at a plurality of locations which lie at substantially equal intervals in the circumferential direction, the fixing of the projection lens to the lens mounting portion is ensured.

In particular, in the event that the extending projections and the stepped portions are disposed, respectively, at three locations which lie in the circumferential direction at substantially equal intervals, the fixing of the projection lens to the lens mounting portion is ensured further. In addition, due to the extending projections and the stepped portions being welded together at the three locations which lie in the circumferential direction at substantially equal intervals and abutment points between the collar portion and the face bearing portion being provided at three locations lying in the vicinity of the welds between the extending projections and the stepped portions, the parallelism between the optical axis of the projection lens and the longitudinal axis of the lens mounting portion can be secured further, and the longitudinal positioning of the focal point of the projection lens and the predetermined position on the lens mounting portion side is secured further, whereby a more desired light distribution (for example, a light distribution having a clear cut-off line which corresponds to the low beam forming shade) can be obtained by the light source unit.

According to a third aspect of the invention, a vehicle lighting device as set forth in the first or second aspect of the invention is provided, wherein a vertical and horizontal positioning means is provided between the rear surface of the collar portion and the face bearing portion in which a pair of projecting pins provided on either of the rear surface of the collar portion and the face bearing portion so as to extend axially and a pair of engagement holes provided on the other so that the projecting pins are brought into engagement therewith are each disposed so that one of the pair faces the other substantially diametrically across the optical axis of the projection lens or the longitudinal axis of the lens mounting portion. For example, the vertical and horizontal positioning means for positioning the projection lens relative to the lens mounting portion is made up of the pair of projecting pins provided on the rear surface side of the collar portion and the pair of pin engagement holes provided on the face bearing portion side When the pair of projecting pins is brought into engagement with the pin engagement holes, the vertical and horizontal positioning of the projection lens relative to the lens mounting portion is automatically implemented. That is, the optical axis of the projection lens and the longitudinal axis of the lens mounting portion are aligned with each other.

In addition, since the pair of projecting pins and the pair of pin engagement holes which make up the vertical and horizontal positioning means are each disposed diametrically oppositely on a straight line which diametrically passes across the optical axis of the projection lens and the longitudinal axis of the lens mounting portion, the vertical and horizontal positioning of the projection lens relative to the lens mounting portion becomes highly accurate.

In the construction in which the pair of projecting pins and the pair of pin engagement holes are provided, since the projecting pins and the pin engagement holes cannot be brought into engagement with each other in the event that the positions thereof deviate from each other even slightly, a high dimensional accuracy is required for the pin projecting positions which lie diametrically across the optical axis of the projection lens and the pin engagement hole forming positions which lie diametrically across the longitudinal axis of the lens mounting portion. However, in the event that one of the pair of pin engagement holes is made up of an elongate hole or slit which extends radially, since the pin and the elongate hole or slit can slide in a radial direction of the projection lens relative to each other when the pin and the elongate hole or slit are brought into engagement with each other, the pin can easily be brought into engagement with the pin engagement hole (e.g., an elongate hole or slit) and also a dimensional error between the pin projecting position and the pin engagement hole forming position in the radial direction of the projection lens can be absorbed. Consequently, the dimensional accuracy required for both the pin projecting position and the pin engagement hole forming position is mitigated.

According to a fourth aspect of the invention, a vehicle lighting device as set forth in any of the first to third aspects of the invention is provided, wherein the extending projection and the stepped portion are welded together axially by means of ultrasonic vibrations. The ultrasonic vibration welding is performed until the collar portion and the face bearing portion reach an abutment position where they are brought into abutment with each other such that the extending projection which is formed slightly longer than a longitudinal length of the stepped portion and a welding surface of the stepped portion are held contacting each other under pressure in the longitudinal direction. When ultrasonic vibrations are transmitted to the press contact portion between the extending projection and the welding surface of the stepped portion while they are held in contact, via a vibration transmitting member (e.g., a horn) and the collar portion of the projection lens, the press contact portion between the extending projection and the welding surface of the stepped portion where ultrasonic vibration energy is received is fused, and a fused distal end portion of the extending projection is coalesced with the welding surface of the stepped portion which is similarly fused so that the extending projection and the stepped portion are welded together. However, since the extending projection and the welding surface of the stepped portion are pressed against each other until the collar portion and the face bearing portion reach the abutment position, the projection lens and the lens mounting portion can be welded together axially into an integrated unit relatively quickly and with good positional accuracy.

According to the vehicle lighting device of the first aspect of the invention, since the protrusion of burrs produced at the welds between the projection lens and the lens mounting portion in the welding process towards the optical axis side of the projection lens is prevented by the erect walls formed on the stepped portions of the lens mounting portion or the projection lens, the vehicle lighting device obtains a proper light distribution which is not adversely affected by the burrs at the welds and provides a good appearance when the lamp is not lit.

According to the second aspect of the invention, since the fixing of the projection lens to the lens mounting portion is secured further, the mounting strength of the projection lens on the lens mounting portion is enhanced accordingly.

According to the third aspect of the invention, since the projection lens and the lens mounting portion are welded and fixed to each other with high positional accuracy such that the optical axis of the projection lens and the longitudinal axis of the lens mounting portion align vertically and horizontally, the vehicle lighting device obtains a proper light distribution by the light source unit. In particular, although the invention is not so limited, the invention is effective for a vehicle lighting device in which a plurality of light source units are provided, whereby a predetermined low beam light distribution pattern is formed by combining proper light beam patterns of the plurality of light source units.

According to the fourth aspect of the invention, since the projection lens and the lens mounting portion can be welded together axially with good positional accuracy in a short period of time into the integrated unit, the vehicle lighting device is provided inexpensively and obtains the proper light distribution which is not adversely affected by the burrs at the welds and provides a good appearance when the lamp is not lit.

Hereinafter, a mode for carrying out the invention is described based on preferred embodiments thereof.

FIGS. 1 to 10show a vehicle lighting device in accordance with a preferred embodiment of the invention.

In these figures, a vehicle lighting device10is a lamp that is provided on a right-hand side (as viewed from the driver's seat) of a front end portion of a vehicle and is constructed so as to accommodate a high beam lamp A, a low beam lamp B and a bending lamp C in that order as viewed from inside thereof in a lamp compartment S which is defined by a lamp body12and a clear transparent cover14mounted on a front end opening in the lamp body12. In this preferred embodiment, the high beam lamp A is made up of five light source units in total which each use a light emitting device34as a light source and which are disposed in two upper and lower stages, so as to form a high beam light distribution pattern by combining respective light beam patterns of the light source units30. In this preferred embodiment, the low beam lamp B is made up of five light source units50which each use a light emitting device54as a light source and which are arranged annularly, so as to form a low beam light distribution pattern by combining respective light beam patterns of the light source units50. The bending lamp C may, for example, include two light source units70(70A,70B) which include reflectors76(76A,76B) on which light emitting devices74,74, as light sources, are mounted and which are arranged vertically, so as to form a curb beam light distribution pattern by combining respective beam patterns of the light source units70A,70B.

Projection lenses32,52and a extension reflector16in which an opening16ais formed so as to correspond to the reflector76are provided, respectively, on a front side of the light source units30,50,70within the lamp compartment S along the transparent cover14so as not only to conceal respective perimeters of the light source units but also to allow the whole of the inside of the lamp compartment S to be seen in the color of a mirror surface. InFIGS. 1,2, the illustration of the extension reflector16is omitted.

The light source unit30, which makes up the high beam lamp A, and the light source unit50, which makes up the low beam lamp B, are configured as projector-type light emitting units having the projection lenses32,52for projecting light at front end portions thereof, respectively. The two light source units70(i.e., upper light source unit70A and lower light source unit70B), which make up the bending lamp C, are each configured as a reflector-type light emitting unit for distributing light by reflecting light from the light source by the reflector76.

A die-cast aluminum low beam lamp bracket20on which the light source unit50making up the low beam lamp B is mounted integrally is supported on a die-cast aluminum lamp housing18which is formed into a rectangular shape so as to rotate horizontally relative thereto. The lamp housing18is configured as a die-cast aluminum product in which a lamp bracket18A for the high beam lamp A and a lamp bracket18C for the bending lamp C are formed integrally to sides thereof and is supported so as to be tilted vertically and horizontally relative to the lamp body12for adjustment of beam direction by an aiming mechanism (e.g. an aiming screw and a pivot fulcrum).

A swivel motor M is disposed on a lower wall18a(refer toFIG. 3) of the lamp housing18, and an output shaft of the motor M is connected to a lower portion of the low beam lamp bracket20, so that the low beam lamp B (see the low beam lamp bracket20on which the light source unit51is mounted integrally) can swivel around a swivel axis (a perpendicular axis) Lz. For example, the driving of the motor M is controlled so as to correspond to a steering angle of a steering wheel by a motor driving control circuit, not shown, so that a horizontal direction of an optical axis (i.e., a light emitting direction) of the low beam B is changed in association with a change in the steering angle of the steering wheel thereby improving visibility when the vehicle is running on a bend.

The die-cast aluminum high beam lamp bracket18A on which the light source unit30is mounted integrally and the die-cast aluminum bending lamp bracket18C on which the light source units70are mounted integrally are formed integrally to the sides of the housing18, which rotatably supports the low beam lamp bracket20on which the light source unit50is mounted integrally

As is shown inFIG. 3, the low beam lamp bracket20includes a perpendicular panel portion20A, unit mounting portions20B, which extend forward in a shelf-like fashion from the perpendicular panel portion20A at five locations which lie at equal intervals in a circumferential direction thereof, and a plurality of heat dissipating fins21provided on a rear surface side of the perpendicular panel portion20A so as to extend vertically. Furthermore, heat sink portions (not shown) made up of heat dissipating Ems may also be provided on the high beam lamp bracket18A and the bending lamp bracket18C (refer toFIGS. 1,2).

The respective light emitting devices34,54,74of the light source units30,50,70are each configured as an LED assembly in which a white light emitting diode is accommodated within a synthetic resin assembly case. Although the light emitting devices generate heat when lit, since the light emitting devices34,54,74are mounted respectively on the bracket18A, the bracket20, the bracket18C formed of die-cast aluminum products, heat generated in the light emitting devices34,54,74can be transmitted quickly to the bracket18A, the bracket20and the bracket18C, each having a large heat capacity, through a heat conducting action. The dissipation of heat to a space within the lamp compartment is further promoted by the heat dissipating fins21, so as to suppress the increase in temperature of the light emitting devices34,54,74. In addition, by adopting this configuration, the reduction in light flux and discoloration of light emitted from the light emitting devices34,54,74can be suppressed effectively.

In addition, a lighting circuit unit13, in which circuits for controlling the lighting of the respective light emitting devices34,54,74of the lamps A, B, C are accommodated integrally, is provided on a lower surface of the lamp body12. Feeding cords15, which are introduced into an interior of the lamp compartment S from the lighting circuit13(refer toFIG. 3), extend to the light emitting devices34,54,74of the lamps A, B, C, respectively. In particular, since the feeding cord15which extends to the light emitting device54in the low beam lamp B is, as shown inFIG. 3, supported by a cord clamp15awhich is provided on the lower wall18aof the housing18in the vicinity of the swivel axis Lz, there is no risk that the cord will interfere with other members due to the rotation of the low beam lamp B.

Next, a specific configuration of the light source unit50will be described.

As is shown inFIGS. 3,4(a), and4(b), the light source unit50includes the resin projection lens52which is a light distribution control member disposed on an optical axis Ax, the light emitting device54(e.g., a white light emitting diode) which is a light source disposed rearward of the projection lens52so as to be oriented upwards, a resin reflector56which is a light distribution control member disposed so as to cover above the light emitting device54, and a resin cut-off line forming shade member58which is a light distribution control member disposed between the light emitting device54and the projection leis52. The light source unit50is mounted integrally on tie low beam lamp bracket20at the unit mounting portions20B thereof.

The reflector56and the shade member58are configured as a reflector integrated shade55which is an integrated mold product of polycarbonate resin or acrylic resin. The reflector integrated shade55is configured such that the light emitting device54is disposed at a primary focal point F1of the reflector56which is made up of an elliptical reflecting surface, while a cut-off line forming upper edge portion58aof the shade member58is positioned at a secondary focal point F2of the reflector56.

As is shown inFIGS. 4(a) and4(b), positioning projections60are provided on a back side of the reflector integrated shade55at three locations in total which include two locations at left and right upper portions and one location at a transversely central lower portion thereof, so as to set a perpendicular reference surface (plane) on the shade55side. In addition, a boss63on which an internally threaded portion62is provided is formed at a substantially central portion of the three positioning projections60so as to project therefrom. In addition, a screw passage hole42is provided in a perpendicular front end wall surface of the unit mounting portion20B, which extends in a cylindrical fashion from the perpendicular panel portion20A of the low beam lamp bracket20. As is shown inFIG. 4(a), a fastening screw40which is passed through the perpendicular front end wall surface from a back side of the unit mounting portion20B is screwed into the internally threaded portion62of the boss63, whereby the three positioning projections60on the back side of the shade55(the shade member58) are brought into press contact with perpendicular front end abutment surfaces20B1lying at three corresponding locations on the unit mounting portions20B, and the shade55is fastened to the unit mounting portions20B in such a state that the optical axis Ax of the light source unit50(a longitudinal axis L2of the reflector integrated shade55) intersects the perpendicular front end abutment surface20B1(the perpendicular panel portion20A) at right angles.

In addition, an LED assembly accommodation compartment20B2is formed on an upper surface of the unit mounting portion20B of the perpendicular panel portion20A. An opening20B3through which an LED assembly is to be inserted into and removed from the LED assembly accommodation compartment is provided in the perpendicular pane) portion20A in a position facing the LED assembly accommodation compartment20B2. In addition, when the LED assembly is accommodated in the LED assembly accommodation compartment20B2from the back side of the perpendicular panel portion20A, the light emitting device54is positioned in the position of the primary focal point F1of the reflector.

The projection lens52may be made, for example, from an acrylic resin and is fixedly integrated with a front end portion (hereinafter, referred to as a lens mounting portion)550of the reflector integrated shade55which is made, for example, from a polycarbonate resin or acrylic resin, by means of ultrasonic vibration welding. As is shown inFIG. 5, the projection lens52and the reflector integrated shade55are positioned so that an optical axis L1of the projection lens52and the longitudinal axis L2of the reflector integrated shade55align accurately (i.e., the projection lens52and the reflector integrated shade55are positioned vertically and horizontally).

As is shown inFIGS. 5,6,7(a), and7(b), arc-shaped collar portions53are formed at two upper and lower locations along an outer circumference of the projection lens which lie diametrically across the optical axis L1of the projection lens. Rear surfaces of the collar portions53each make up an abutment reference surface on the lens52which is perpendicular to the optical axis L1. On the other hand, as is shown inFIGS. 5 and 8, arc-shaped face bearing portions552are formed at a distal end of the lens mounting portion550so as to correspond to the collar portions53, and the face bearing portions552each make up an abutment reference surface on the shade55side which is perpendicular to the longitudinal axis L2. Consequently, by bringing the rear surfaces (i.e., the abutment reference surfaces on the lens52side) of the collar portions53of the projection lens52into abutment with the face bearing portions552(i.e., the abutment reference surfaces on the shade55side), the optical axis L1of the projection lens52and the longitudinal axis L2of the reflector integrated shade55are positioned parallel to each other.

In addition, as shown inFIGS. 5 and 8, a pair of projecting pins554,554are provided, respectively, on the face bearing portions552of the lens mounting portion550so as to lie opposite diametrically across the longitudinal axis L2, and on the other hand, as is shown inFIGS. 6,7, a pin engagement hole532and a slit533, which correspond to the pair of projecting pins554,554, are provided, respectively, on the rear surfaces of the collar portions53of the projection lens so as to lie opposite diametrically across the optical axis L1. The pair of pins554,554and the pin engagement hole532and the slit533make up a positioning means for aligning the optical axis L1of the projection lens52with the longitudinal axis L2of the reflector integrated shade55. Namely, by bringing the pair of pins554,554into engagement with the pin engagement hole532and the slit533, respectively, the optical axis L1of the projection lens52and the longitudinal axis L2of the reflector integrated shade55are aligned with each other accurately, so that the optical axis L1and the longitudinal axis L2cooperate with each other to make up the optical axis Ax of the light source unit50.

Although the positioning means for aligning the optical axis L1of the projection lens52with the longitudinal axis L2of the reflector integrated shade55can be made up of the pair of projecting pins554,554and the pair of pin engagement holes532,532, the pair of projecting pins554,554and the pair of pin engagement holes532,532cannot be brought into proper engagement with each other if the positions of the projecting pins and the pin engagement holes deviate from each other even slightly. Therefore, a high dimensional accuracy is required for the pin projecting positions which lie diametrically opposite across the optical axis L1of the projection lens and the pin engagement hole532forming positions which lie diametrically opposite across the longitudinal axis L2of the lens mounting portion550, which constricts the manufacturing conditions of the reflector integrated shade55. On the other hand, in this preferred embodiment, one of the engagement holes with which the pair of projecting pins554are brought into engagement is made up of the slit533which extends in the radial direction. Since the projecting pin554and the slit533can slide in the radial direction of the projection lens52relative to each other when the projecting pin554is brought into engagement with the slit533, the pin554and the pin engagement hole532can easily be brought into engagement with each other. Since a dimensional error of the pin554projecting positions and the pin engagement hole532forming positions in the radial direction of the projection lens52can be absorbed, the dimensional accuracy required for the pin projecting positions and the pin engagement hole forming positions is mitigated.

In addition, as is shown inFIGS. 6 and 7, a rearward extending projection536is provided on the rear surface of each of the upper and lower collar portions53of the projection lens52closer to an outer circumference thereof so as to extend in an arc-like shape along the outer circumference of the collar portion53, while as is shown inFIGS. 5,8and9, a stepped portion556is provided on an outer circumference of the lens mounting portion550in a position which corresponds to the rearward extending projection536on the lens52side so that the rearward extending projection536can be brought into axial engagement therewith. As is shown inFIG. 10(a), the stepped portion536is formed to have a width d, which is slightly larger than a thickness t of the rearward extending projection536on the lens52side, and a depth (a longitudinal length) H, which is somewhat shallower than a longitudinal length h of the rearward extending projection536. Due to this, a gap is formed around the rearward extending projection536, in particular, between the rearward extending projection536and an erect wall556bsuch that the rearward extending projection536is brought into engagement with the stepped portion556.

The length of the projecting pin554is set to be somewhat larger than a difference (h−H) between the longitudinal length h of the rearward extending projection536and the depth (the longitudinal length) H of the stepped portion556, so that distal end portions of the projecting pins554,554can be brought into engagement with the pin engagement hole532and the slit533, respectively, when the rearward extending projection536is brought into engagement with the stepped portion556. When the distal end portions of the projecting pins554,554are brought into engagement with the pin engagement hole532and the slit533, the rearward extending projection536and the stepped portion556are automatically brought into engagement with each other.

The rearward extending projection536is ultrasonically welded to a welding surface556aof the stepped portion556so that the rear surface of the collar portion53of the projection lens52is brought into abutment with the face bearing portion552of the lens mounting portion550. A focal point f of the projection lens52is thereby aligned with the secondary focal point F2of the reflector integrated shade55(i.e., of the reflector56).

As shown inFIGS. 9 and 10(a), the erect wall556b,which is an inner circumferential wall of the stepped portion556of the lens mounting portion550, extends along an inside of the rearward extending projection536on the lens52side to function as a barrier for preventing resin, which is fused when the rearward projection536on the lens52side is welded to the stepped portion556, from flowing out towards an optical axis L1side of the projection lens52. Preventing the flow of resin helps to avoid the protrusion (exposure) of burrs produced at a weld between the rearward extending projection536and the stepped portion556towards the optical side of the projection lens52. Preventing the burr exposure avoids defects that could adversely affect the light distribution and cause the burrs at the weld to become visible through the projection lens52.

Next, a process for welding and fixing the projection lens52to the reflector integrated shade55will be described based onFIG. 10.

Firstly, the reflector integrated shade55is set on a jig (not shown) so that the lens mounting portion550is oriented upwards. Then, the projection lens52is assembled to the lens mounting portion550so that the pin engagement hole532and the slit533on the lens52side are brought into engagement with the distal end portions of the projecting pins554,554on the lens mounting portion550side. As this occurs, as is shown inFIG. 10(a), a state results in which the rearward extending projection536on the lens52side is brought into engagement with the stepped portion556on the lens mounting portion550side, whereby a distal end of the rearward extending projection536is brought into abutment with the welding surface556aof the stepped portion556. Following this, a cut-type horn100is lowered from above the projection lens52, whereby an annular lower end portion of the horn100presses against the collar portion53of the projection lens52, and the rearward extending projection536is held contacting the welding surface556aof the stepped portion556under pressure. Then, ultrasonic vibrations are transmitted to the collar portion53via the horn100while keeping the rearward extending projection536in contact with the welding surface556aof the stepped portion556under pressure. A press contact portion between the rearward extending projection536and the welding surface556aof the stepped portion556which receives ultrasonic vibration energy is fused, and a fused distal end portion of the rearward extending projection536is coalesced with the welding surface556aof the stepped portion556which is similarly fused so that the rearward extending projection536and the stepped portion556are welded together. However, as is shown inFIG. 10(b), since the rearward extending projection536on the projection lens52side and the welding surface556aof the stepped portion556are held pressed against each other until the collar portion53and the face bearing portion552reach the abutment position where they are brought into abutment with each other, the projection lens52and the lens mounting portion550(the reflector integrated shade55) can be welded together axially (longitudinally) with good positional accuracy over a short period of time into an integrated unit. During the process in which the extending projection536on the lens52side is welded to the stepped portion536, the erect wall556bof the stepped portion556which extends along the inside of the extending projection536functions as the barrier for preventing the fused resin from flowing out towards the optical axis L1side of the projection lens52, whereby the protrusion (exposure) of burrs produced at the weld between the extending projection536and the stepped portion556is prevented.

In addition, of the light source units70which are positioned at the two upper and lower locations to make up the bending lamp C, in the upper light source unit70A, an optical axis thereof is inclined slightly outwards in the transverse direction of the vehicle so as to form a light distribution pattern which illuminates widely a diagonally front area of the vehicle, whereas in the lower light source unit70B, an optical axis thereof is inclined largely outwards in the transverse direction of the vehicle so as to form a light distribution pattern which illuminates a limited area lying in a more diagonally front area of the vehicle.

Additionally, the light source unit30which makes up the high beam lamp A includes, as is shown inFIGS. 1 and 2, the resin projection lens32which is a light distribution control member disposed on an optical axis A′x, the light emitting device34(e.g., a white light emitting diode) which is the light source disposed on the unit mounting portion provided on the bracket18A so as to be oriented upwards, a resin reflector36which is a light distribution control member disposed so as to cover the light emitting device34from above, and a resin lens holder38disposed between the light emitting device34and the projection lens32.

As to the lens holder38making up the light source unit30, as with the reflector integrated shade55which makes up the light source unit50, the reflector36and the lens holder38are made into a reflector integrated lens holder35which is an integrated mold product of a polycarbonate resin or acrylic resin, for example. In addition, a positioning means (e.g., pin engagement holes and rearward extending projections on the projection lens side and projecting pins and stepped portions on the lens holder35side) which is similar to that provided between the reflector integrated shade55and the projection lens52of the light source unit50is provided between a distal end portion of the reflector integrated lens holder35and a collar portion of the projection lens32, and the acrylic resin projection lens32is integrated with a distal end of the reflector integrated lens holder35by means of ultrasonic vibration welding.

In the above preferred embodiment, the pin engagement hole532and the slit533are provided on the side of the projection lens52to correspond to the pair of projecting pins554provided on the side of the lens mounting portion550as the vertical and horizontal positioning means between the projection lens52and the reflector integrated shade55. In another embodiment an elongated hole may be provided in place of the slit533. In addition, a pair of pin engagement holes532may be provided on the side of the lens mounting portion550to correspond to the pair of projecting pins554provided on the side of the projection lens52.

The above preferred embodiment is configured such that the projection lens52and the lens mounting portion550are positioned relative to each other so that the optical axis L1of the projection lens is substantially aligned with the longitudinal axis L2of the lens mounting portion550and welded integrally by the rearward extending projections536which are provided at the three locations (one upper and two lower locations) and the stepped portions556which are provided at the three locations which correspond to the projections536, respectively. In another embodiment, the rearward extending projections536and the corresponding stepped portions556may be provided so as to lie at three locations which are situated circumferentially at substantially equal intervals, respectively, which will further ensure the fixing of the projection lens52to the lens mounting portion550, and ensure the parallelism between the optical axis L1of the projection lens52and the longitudinal axis L2of the lens mounting portion550. The longitudinal positioning of the focal point f of the projection lens52and the predetermined position on the lens mounting portion550side is secured further, so that a more desired light distribution (for example, a light distribution having a clear cut-off line which corresponds to the low beam forming shade) can be obtained by the light source unit50.

Additionally, while in the above preferred embodiment, the rearward extending projections536and the stepped portions556are provided at the three locations, respectively, a configuration may be adopted in which the rearward extending projections536and the stepped portions556are provided at two locations which lie opposite diametrically to face each other across the optical axis L1(the longitudinal axis L2).

While in the above preferred embodiment, the plurality of rearward extending projections536are provided on the back sides of the collar portions53of the projection lens52and the stepped portions556are formed on the face bearing portions552of the lens mounting portion550so that the extending projections536can be brought into engagement therewith, another embodiment may be adopted in which as is shown inFIG. 11(a), a plurality of forward extending projections536′ are provided on face bearing portions552of a lens mounting portion550, while stepped portions556′ are provided on back sides of collar portions53of a projection lens52so that the extending projections536′ can be brought into engagement therewith. In other regards, the relevant configuration is similar to the configuration realized by the lens mounting portion550and the projection lens52in the first embodiment above, and hence, the repetition of that description is omitted here.

FIGS. 11(a) and11(b) are explanatory diagrams according to another embodiment of the invention.FIG. 11(a) is an enlarged sectional view showing an engagement portion between the forward extending projection536′ and the stepped portion556′ right before the start of an ultrasonic vibration welding process, andFIG. 11(b) is an enlarged sectional view showing the engagement between the forward extending projection536′ and the stepped portion556′ at the completion of the ultrasonic vibration welding process.

The welding process for fixing the projection lens52to a reflector integrated shade55differs from the process of the first embodiment (refer toFIGS. 10(a), (b)). As is shown inFIG. 11(a), the reflector integrated shade55is assembled from above to the projection lens52, which is set on a jig so that a rear surface side thereof is oriented upwards. Then, a cup-type horn engagement annular notch (stepped portion)552is formed on an outer circumference of the lens mounting portion550of the reflector integrated shade55so as to extend along the forward extending projection536′. A cup-type horn100′ is brought into engagement with the notch (stepped portion) so as to cover the reflector integrated shade55from above, ultrasonic vibrations are transmitted to the forward extending projection536′ via the horn100′ while causing the forward extending projection536′ to be pressed against a welding surface556′aof the stepped portion556′, whereby as is shown in FIG.11′b), the forward extending projection536′ and the stepped portion556′ are welded integrally in a position where a rear face (back side) of the collar portion53is brought into abutment with the face bearing portion552. Also, in the process shown inFIGS. 11(a) and11(b), during the process in which tie extending projection536′ on the face bearing portion552side of the lens mounting portion550is welded to the stepped portion556′ of the lens52, an erect wall556′bon the stepped portion556′ which extends along an inside of the extending projection536′ functions as a barrier for preventing fused resin from flowing out towards an optical axis L1side of the projection lens52to thereby avoid the protrusion (exposure) of burrs produced at the weld between the extending projection536′ and the stepped portion556′ towards the optical axis side of the projection lens52.

In addition, in either of the two embodiments (FIGS. 10(a), (b) andFIGS. 11(a), (b)) that have been described heretofore, the vertical and horizontal positioning means between the projection lens52and the lens mounting portion550(i.e., the positioning means for aligning the optical axis L1of the projection lens52with the longitudinal axis L2of the reflector integrated shade55with high accuracy) are made up of the pair of projecting pins554which are provided on the face bearing portions552of the lens mounting portion550and the pin engagement hole532and the slit533which are provided on the rear surface side of the collar portions53of the projection lens52. Since the three extending projections536(526′) on the projection lens52(or the lens mounting portion550) side and the corresponding stepped portions566(556′) on the lens mounting portion550(or the projection lens52) side function as the positioning means for substantially aligning the optical axis L1of the projection lens52with the longitudinal axis L2of the reflector integrated shade55vertically and horizontally, the vertical and horizontal positioning means which is made up of the projecting pins554and the pin engagement holes532(including the slit533) is not necessarily required.

When the plurality of extending projections536(536′) on the projection lens52(or the lens mounting portion550) side and the corresponding stepped portions556(556′) on the lens mounting portion550(or the projection lens52) side are brought into axial (longitudinal) engagement with each other, respectively, the focal point f of the projection lens52, the secondary focal point F2of the reflector56and the cut-off line forming upper edge portion58acan be substantially aligned with each other in the vertical and horizontal directions, but they cannot always be aligned with each other accurately. In forming a light distribution having a clear cut-off line which corresponds to the cut-off line forming shade member58(the cut-off line forming upper edge portion58a) by the light source unit50, however, as long as at least the optical axis L1of the projection lens52and the longitudinal axis L2of the lens mounting portion550are parallel and the focal point f of the projection lens52, the secondary focal point F2of the reflector56and the cut-off line forming upper edge portion58aare aligned with each other axially (longitudinally), there will be no serious problem even if the focal point f of the projection lens52, the secondary focal point F2of the reflector56and the cut-off line forming upper edge portion58adeviate from each other somewhat vertically and/or horizontally.

Although the invention has been described above with respect to preferred 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 spirit and scope of the invention as disclosed and claimed herein, and such modifications are intended to fall within the scope of the appended claims.