Abstract:
A vehicle headlamp unit that is configured for use with either a halogen lamp or a high intensity discharge lamp. The headlamp unit includes a housing within which a reflector is located for reflecting light from the headlamp unit. A lamp is supported within the reflector and a lamp socket is electrically connected to the lamp. The lamp socket including a wire harness receptacle having a first configuration that is configured to matingly engage the wire harness connector. A secondary receptacle is also connected to the housing. The secondary receptacle has a second configuration that at least partially duplicates the first configuration and is configured to matingly engage the wire harness connector. Accordingly, both the wire harness receptacle and the secondary receptacle are configured to alternately receive and matingly engage the wire harness connector.

Description:
BACKGROUND 
     1. Field of Invention 
     The present invention relates generally to vehicle headlamps and, more particularly, to a vehicle headlamp unit having an electrical connection that is compatible with both halogen and high intensity discharge (HID) lamps. 
     2. Related Technology 
     Different vehicle headlamp systems use different types of lamps. While they are most commonly equipped with halogen lamps, recently there has been a trend towards adopting high intensity discharge (HID) lamps. In a halogen lamp an electric current passes through a high-resistance tungsten filament which generates light. In an HID lamp, instead of a filament, an arc is created between a pair of electrodes, which excites a gas (commonly xenon) inside the lamp that vaporizes metallic salts. These metallic salts help sustain the arc and provide a consistent lamp intensity. Compared to HID lamps, halogen lamps operate at a low power voltage (12 or 24 volts) and can directly use the voltage from the vehicle power. HID lamps operate at much higher voltage, approximately 20 kilovolts (kV). Thus, a separate lighting circuit is required to generate the high voltage for lighting the HID lamp. 
     HID headlamp systems are attractive to automotive manufacturers because of their longer lifespan, better durability, and greater performance and power efficiency. Despite the numerous advantages of HID lamps, manufacturers have not entirely replaced halogen lamps with HID lamps because they are expensive compared, to halogen lamps. and they have a tendency to cause more discomfort glare for oncoming drivers. Accordingly, a vehicle may be designed to alternately accommodate halogen and HID headlamps, depending on which is desired by the end consumer. A unique wiring harness, for supplying power from the vehicle to the lamp, is currently required for each version of the headlamp due to the difference in design and power supply requirements in halogen and HID headlamps. This further increases cost and complexity in the internal structure of the vehicle by requiring different wire harness designs and components for each version. 
     SUMMARY 
     In overcoming the enumerated drawbacks and other limitations of the related art, the present invention provides a vehicle headlamp unit having an electrical connection that is compatible with either halogen or HID lamps. 
     In one aspect of the invention, a vehicle headlamp comprises a lamp housing and a lens; the lens being mounted in an opening in the front of the lamp housing. A reflector is also mounted in the housing and a lamp is centrally located in the reflector. The lamp itself may be either a halogen lamp or a discharge lamp, comprising a bulb and a base. 
     In a halogen headlamp, the lamp comprises electrical contacts which connect to electrical leads of the lamp base. The lamp socket comprises a lamp socket cavity including a closed end having apertures and an open end. The closed end and the open end are defined by first and second ellipsoidal walls, respectively, the circumference of the second ellipsoidal wall being greater than the circumference of the first ellipsoidal wall. The lamp socket comprises wire leads which form an electrical connection with electrical contacts to light the bulb. The wire leads are inserted through the apertures in the closed end of the lamp socket cavity and extend to the open end of the lamp socket cavity. A wire harness for supplying power from a vehicle power supply connects into the lamp socket cavity and forms an electrical connection with the wire leads. The lamp housing cavity is molded to correspond with the shape of the lamp socket cavity. The lamp housing cavity remains unoccupied in a halogen headlamp. 
     In a discharge headlamp, where high voltage is required to light the discharge bulb, a lighting circuit unit is required for supplying a high voltage to the electrical connection device of a lamp socket. The lighting circuit unit is contained within the housing and receives power from a power supply cord. The power supply cord comprises a cord connector which passes through the lamp housing cavity of the lamp housing. The lamp housing cavity is molded to correspond with the shape of the lamp socket cavity of a halogen lamp. Accordingly, the lamp housing cavity includes a closed end with apertures and an open end. The closed end and the open end are defined by first and second ellipsoidal walls, respectively, the circumference of the second ellipsoidal wall being greater than the circumference of the first ellipsoidal wall. The cord connector having metal leads passes through the lamp housing cavity, the metal leads being inserted through the apertures in the closed end and extending to the open end of the lamp housing cavity. Thus, the geometry of the lamp socket cavity of the halogen lamp is integral to the lamp housing cavity containing the cord connector metal leads. Hence, the wire harness that is configured to connect to the lamp socket cavity of the halogen lamp for supplying power from a vehicle power supply is compatible with the lamp housing cavity. Accordingly, in a discharge headlamp, where a cord connector passes through the lamp housing cavity, the wire harness connects into the lamp housing cavity and forms an electrical connection with the metal leads of the connector. 
     Once the lighting circuit unit receives power from the wire harness through the power supply cord, two high voltage power supply cords supply the high voltage from the lighting circuit to the lamp socket. The electrical connection device in the lamp socket then supplies the power to ignite the discharge bulb. 
     In at least one embodiment, the vehicle headlamp unit comprises a lamp housing having a front end and a rear end and openings in both the front and rear ends. A lens is mounted in the front end opening. A reflector is mounted within the lamp housing and a lamp is mounted on the reflector. The lamp is one of a first lamp or a second lamp and comprises a bulb, a lamp base, and a lamp socket. The lamp socket includes an electrical connection device. The lamp socket of a first lamp includes a lamp socket body for receiving the lamp base and a lamp socket cavity for receiving a vehicle power supply. A lamp housing cavity is molded into the lamp housing, projecting from the rear end of the lamp housing. The lamp housing cavity is configured to receive a vehicle power supply. The geometry of the lamp housing cavity is designed to correspond with the geometry of the lamp socket cavity of the lamp socket of a first lamp. 
     The vehicle headlamp unit may comprise a first lamp or a second lamp, wherein the first lamp is a halogen lamp and the second lamp is a discharge lamp. 
     In another embodiment, the geometry of the lamp socket cavity of the lamp socket of a first lamp includes a closed end with at least one aperture and an open end for receiving a vehicle power supply. The closed end and the open end are defined by a first and second ellipsoidal wall, respectively, wherein the circumference of the second ellipsoidal wall is greater than the circumference of the first ellipsoidal wall. 
     In another embodiment, the vehicle headlamp includes at least one electrical contact having a top end and a bottom end and the lamp base of a first lamp comprises at least one electrical lead. The at least one electrical contact is received in the lamp socket body having a front end and a rear end. The top end of the at least one electrical contact is configured to engage the at least one electrical lead of the lamp base at the front end of the lamp socket body and the bottom end of the at least one electrical contact extends from the rear end of the lamp socket body. 
     In another embodiment, the lamp socket of a first lamp comprises at least one wire lead having a top end and a bottom end, wherein the top end is configured to form a first electrical connection with the at least one electrical contact extending from the rear of the lamp socket body, and wherein the bottom end of the at least one wire lead is inserted through the at least one aperture in the closed end of the lamp socket cavity and configured to form a second electrical connection with a vehicle power supply. 
     In another embodiment, wherein the vehicle headlamp comprises a first lamp, a harness for supplying power from a vehicle power supply to the first lamp connects into the open end of the lamp socket cavity, forming a second electrical connection with the at least one wire lead. The first electrical connection between the at least one wire lead and the at least one electrical contact then supplies power to light the lamp bulb. 
     In another embodiment, wherein the vehicle headlamp comprises a second lamp, a lighting circuit unit is disposed within the lamp housing for providing a first electrical connection to the lamp socket of the lamp. A first power supply cord for providing a second electrical connection to the lighting circuit unit is positioned between the lighting circuit unit and the rear end of the lamp housing. The first power supply cord includes a first cord connector designed to pass through the lamp housing cavity molded into the rear end of the lamp housing, wherein the first cord connector includes metal leads, the metal leads being configured to connect to a vehicle power supply and form the second electrical connection. 
     A second power supply cord for providing the first electrical connection to the lamp is positioned between the lighting circuit unit and the lamp socket of the lamp for supplying power from the lighting circuit unit to the electrical connection device of the lamp socket. A harness for supplying power from a vehicle power supply to the first power supply cord connects to the first cord connector through the lamp housing cavity at the rear end of the lamp housing. The geometry of the lamp housing cavity is configured to correspond with the geometry of the lamp socket cavity of the lamp socket of a first lamp. Thus, the harness is compatible with both the lamp socket cavity of a first lamp and the lamp housing cavity molded into the lamp housing. A back cover may be mounted in the opening of the rear end of the lamp housing. 
     In another aspect, the vehicle headlamp unit comprises a lamp housing having a front end and a rear end and openings in both the front and rear ends. A lens is mounted in the front end opening. A reflector is mounted within the lamp housing and a lamp is mounted on the reflector. The lamp is one of a first lamp or a second lamp and comprises a bulb, a lamp base, and a lamp socket. The lamp socket includes an electrical connection device. The lamp socket of a first lamp includes a lamp socket body for receiving the lamp base and a lamp socket cavity for receiving a vehicle power supply. A lamp housing cavity is molded into the lamp housing, projecting from the rear end of the lamp housing. The lamp housing cavity is configured to receive a vehicle power supply. The geometry of the lamp housing cavity is designed to correspond with the geometry of the lamp socket cavity of the lamp socket of a first lamp. A harness provides a first electrical connection from a vehicle power supply to light the lamp. The harness is compatible with both a vehicle headlamp unit comprising a first lamp and a vehicle headlamp unit comprising a second lamp. Where the vehicle headlamp comprises a first lamp, the harness is configured to connect in the lamp socket cavity of the lamp socket of the first lamp. Where the vehicle headlamp comprises a second lamp, the harness is configured to connect in the lamp housing cavity molded into the lamp housing. 
     The vehicle headlamp unit may comprise a first lamp or a second lamp, wherein the first lamp is a halogen lamp and the second lamp is a discharge lamp. 
     In another embodiment, the geometry of the lamp socket cavity of the lamp socket of a first lamp includes a closed end with at least one aperture and an open end for receiving a vehicle power supply. The closed end and the open end are defined by a first and second ellipsoidal wall, respectively, wherein the circumference of the second ellipsoidal wall is greater than the circumference of the first ellipsoidal wall. 
     In another embodiment, the vehicle headlamp includes at least one electrical contact having a top end and a bottom end and the lamp base of a first lamp comprises at least one electrical lead. The at least one electrical contact is received in the lamp socket body having a front end and a rear end. The top end of the at least one electrical contact is configured to engage the at least one electrical lead of the lamp base at the front end of the lamp socket body and the bottom end of the at least one electrical contact extends from the rear end of the lamp socket body. 
     In another embodiment, the lamp socket of a first lamp comprises at least one wire lead having a top end and a bottom end, wherein the top end is configured to form a second electrical connection with the at least one electrical contact extending from the rear of the lamp socket body, and wherein the bottom end of the at least one wire lead is inserted through the at least one aperture in the closed end of the lamp socket cavity and configured to form a first electrical connection with the harness. 
     In another embodiment, wherein the vehicle headlamp comprises a second lamp, a lighting circuit unit is disposed within the lamp housing for providing a second electrical connection to the lamp. A first power supply cord for providing a second electrical connection to the lighting circuit unit is positioned between the lighting circuit unit and the rear end of the lamp housing. The first power supply cord includes a first cord connector designed to pass through the lamp housing cavity molded into the rear end of the lamp housing, the first cord connector having metal leads, the metal leads being configured to connect to the harness and form the first electrical connection. A second power supply cord for providing the second electrical connection to the lamp is positioned between the lighting circuit unit and the lamp socket of the lamp for supplying power from the lighting circuit unit to the electrical connection device of the lamp socket. A back cover may be mounted in the opening of the rear end of the lamp housing. 
     The geometry of the lamp housing cavity is configured to correspond with the geometry of the lamp socket cavity of the lamp socket of a first lamp. Thus, the lamp housing cavity comprises a closed end having apertures and an open end, the closed end and the open end being defined by first and second ellipsoidal walls, the circumference of the second ellipsoidal wall being greater than the circumference of the first ellipsoidal wall. Analogous to the wire leads of the lamp socket of a first lamp which pass through the apertures in the closed end of the lamp socket cavity, the metal leads of the cord connector are inserted through apertures in the closed end of the lamp housing cavity. Thus, the harness is compatible with both a first lamp headlamp and a second lamp headlamp, the harness being configured to form an electrical connection with the wire leads of the lamp socket cavity of a first lamp, and alternatively, with the metal leads of the cord connector in the lamp housing cavity in a second lamp headlamp. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a cross-sectional view of a vehicle headlamp embodying the principles of the present invention and employing a halogen lamp; 
         FIG. 2  is a cross-sectional view of the headlamp seen in  FIG. 1  employing a HID lamp; 
         FIG. 3  is a perspective view, with portion cut away, of a lamp socket for a halogen lamp; 
         FIG. 4  is a perspective view of the duplicate connection see in  FIGS. 1 and 2 ; and 
         FIG. 5  is a perspective view of a wiring harness connector. 
     
    
    
     DETAILED DESCRIPTION 
     The following description of the preferred embodiments of the invention is not intended to limit the scope of the invention to these preferred embodiments, but rather to enable any person skilled in the art to make and use the invention. 
     Turning now to the figures, depicted therein is a cross-sectional view of a vehicle headlamp assembly or unit  10  embodying the principles of the present invention. The vehicle headlamp  10  includes a headlamp housing  12  having an opening  16  in the front end and an opening  17  in the rear end thereof. A lens  14  is mounted in the opening  16  and a reflector  20  is supported within the housing  12 . Centrally located within the reflector  20  is a lamp. As further discussed below, the lamp may be either a halogen lamp or an HID lamp since the headlamp  10  is designed to accommodate either variety. 
     The lamp includes a bulb and a base. As shown in  FIG. 1 , the base  126  includes a pair of contacts  127  extending therefrom. It will be appreciated, that the base  126  is being generically presented and the specific configure of the base  126  will depend on the particular type and variety of lamp being used in the headlamp  10 . 
     As noted above and as will be seen from the discussion which follows, the headlamp  10  is designed to accept either halogen lamps or HID lamps and specific features are formed in the headlamp  10  to achieve this goal. As such, a secondary receptacle  21  is connected to the housing  12 , such as being formed in a wall  23  of the housing  12 . As seen in  FIG. 1 , the headlamp  10  is employed with a halogen lamp  22 . In  FIG. 3 , the headlamp  10  is shown employing an HID lamp  22 . 
     Further, referring to  FIG. 1 , the headlamp  10  is illustrated therein employing a halogen lamp  122  having a bulb  124  and a base  126 . Coupled to the base  126  of the halogen lamp  122  is a halogen lamp socket  28 . The lamp socket  28  connects directly to the base  126  of the halogen lamp  122 . Accordingly, the lamp socket  128  includes a lamp receptacle  30  having an appropriately shaped receptacle cavity  33  defined therein (as seen in  FIG. 3 ). The cavity  33  is correspondingly shaped to receive the base  126 . As shown in  FIG. 3 , the cross-sectional shape of the receptacle cavity  33  corresponds to the cross-sectional shape of the lamp base  126  and receives the lamp base  126  in a press fit engagement. If the lamp base included terminals projecting therefrom (as shown in  FIG. 1 ), the receptacle cavity  33  would appropriately include features for electrically engaging the terminals  127 . The lamp socket  28  further includes a socket body  32  to which the lamp receptacle  30  may be configured for snap fit engagement. Alternatively, the lamp receptacle  30  and socket body  32  may be unitarily formed with each other. The snap engagement, however, allows for the socket body  32  to accept lamps  122  with alternative base  126  configurations by merely coupling it with an appropriately configured lamp receptacle  30 . 
     The lamp socket  28  further includes a wire harness receptacle  35  configured to receive a wire harness connector  64  coupled to the power supply of the vehicle (not shown). The connector  64  is appropriately shaped to engage and be retained with the wiring harness receptacle  35  and also include contacts therein to engage electrical contact terminals  50  and  51  within the wiring harness receptacle  35 , which are in turn connected to the contacts  127  of the halogen lamp  122 . While the wire harness receptacle  35  and the wiring harness connector  64  may have a variety of configurations, they are illustrated respectively as female and male portions shaped so as to matingly engage one another via the end  65  of the connector  64  being received within the cavity  59  defined within a side wall  60  of the receptacle  35 . Additionally, as illustrated, the receptacle  35  is provided with a locating feature  62  in the form of an elongated finger. The locating feature  62  may be utilized to ensure proper orientation of the connector  64  within the receptacle  35 . With the wiring harness connector  64  engaged with the wiring harness receptacle  35 , an electrical connection is made between the power supply system of the vehicle and the halogen lamp  122 . Accordingly, the halogen lamp  122  may be powered on as required during operation of the vehicle. 
       FIG. 4  is a perspective view of the secondary receptacle  21 , projecting from the rear end  19  of the wall  23  of the lamp housing  12 . The secondary receptacle  21  is shaped so as to correspond and have the same shape as the wire harness receptacle  35  of the socket body  32 . As with receptacle  35 , the secondary receptacle  21  is appropriately shaped to receive and engage the wire harness connector  64 . The secondary receptacle  21  includes a closed end  68 , having apertures  70  and  72  therethrough, and an open end  74  for receiving the connector  64  of the vehicle power supply. Centrally located between the apertures  70  and  72  is a locating feature  73 , which serves the same purpose as the locating feature  62  of the wire harness receptacle  35 . 
     As shown in  FIG. 1 , when used with a halogen lamp  122 , the voltage is directly transmitted from the power supply of a vehicle to illuminate the bulb  124 . The wire harness  64  connects to the wire harness receptacle  35  of lamp socket  28 . Notably, the secondary receptacle  21  of lamp housing  12  is left unoccupied. 
       FIG. 2  depicts a cross-sectional view of the vehicle headlamp  10  utilizing a HID lamp  112  according to the present invention. The construction of the headlamp  10  may be generally the same as with the prior embodiment except for the connecting of the lamp  112  to the vehicle power supply. For this reason, the prior discussion regarding the housing  12 , lens  14  and reflector  20  is not repeated and the reader&#39;s attention is directed to the prior sections hereof where those elements are discussed. It is noted, however, that configuration of the reflector  20  and dimensions of the headlamp  10  may be altered as desired or required for use with the HID lamp  112 . The discharge lamp  112  thus includes a discharge bulb  114  and a lamp base  116  and is mounted on the reflector  20 . 
     Since different power requirements are needed for the HID lamp  112 , a lighting circuit unit  128  is provided in the lamp housing  12  for igniting the discharge bulb  114 . The lighting circuit unit  128  includes an electrical circuit constructed by a converter, an inverter, an igniter and the like and is only generally shown in the drawings. The converter will increase the direct-current (DC) voltage from the vehicle&#39;s battery, and the inverter converts the DC voltage to an alternating-current (AC) voltage. The igniter is the starting circuit for generating the high voltage required for initially lighting the HID lamp  112 . The lighting circuit unit  128  supplies its high voltage to the HID lamp  112  through one or more high voltage power supply lines  130 , which are electrically connected in a lamp socket  118  of the HID lamp  112 . 
     Power supply lines  132  extend from the lighting circuit unit  128  and, at its end, includes a power supply connector  138 . The cord connector  138  is designed to replicate features of the wiring harness receptacle  35 . In particular, the cord connector  138  includes electrical contact terminals  140  and  142 . The contact terminals  140  extend through the apertures  70  and  72  formed in the closed end  68  of the secondary receptacle  21  of the lamp housing and are positioned on opposite sides of the locating feature  73 . Latching tabs  144  and  146  extend from the connector  138 , adjacent to the terminals  140  and  142 , and are configured to secure the cord connector  138  relative to the secondary receptacle  21 . The tabs  144  and  146  also extend through the apertures  70  and  72  and may include locking features or shoulders to aid in retaining the connector  138  relative to secondary receptacle  21 . 
     Accordingly, a wire harness connector  64  connects through secondary receptacle  21  and provides power from the vehicle power supply via the contact terminals  140  and  142  to the lighting circuit unit  128 . The lighting circuit unit  128  thereafter supplies a high voltage power to a lamp socket  118  connected to the HID lamp  112 . 
     If desired, a rear cover plate  124  may be removable provided over the opening  17  in the rear end  19  of the housing  12  to allow access and replacement of the lamp  112 . 
     As seen in  FIGS. 1 and 2 , the geometry of the wire harness receptacle  35  and the secondary receptacle  21  is the same and allows the wire harness connector  64  to be compatible with both, thus permitting the halogen headlamp version and the discharge headlamp version of the assembly  10 . 
     Alternative embodiments other than those described above may be used with the present invention. It is therefore intended that the foregoing detailed description be regarded as illustrative rather than limiting, and that it be understood that it is the following claims, including all equivalents, that are intended to define the spirit and scope of this invention.