Abstract:
A lamp assembly comprising a transparent body having a front surface and a back surface, the back surface having at least one convex curved portion, each such convex curved portion having at least one axis perpendicular to the front surface, and an internally reflective curved surface facing the front surface of the transparent body, a cavity in each convex curved portion, having sidewalls and a bottom, adapted to receive a light emitting source, and a reflective surface at the bottom of each cavity oriented so that light emitted by the light emitting source is reflected by the reflective surface onto the internally reflective curved surface of the convex curved portion. In some embodiments, the internally reflective curved surface also provides one or more electrical circuits for one or more light emitting sources.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The invention relates to a vehicular lamp assembly with a simplified structure. In one of its aspects, the invention relates to a vehicular lamp assembly and a center high-mount stop lamp incorporating the same. In another of its aspects, the invention relates to a vehicular lamp body incorporating the reflective surface applied to a rear portion thereof. In another of its aspects, the invention relates to a lamp body having a reflective surface that forms a part of an electrical circuit for powering a plurality of lamps installed thereon. In another of its aspects, the invention relates to a lamp body having a reflective surface adjacent to rear surface thereof in combination with optical elements adjacent to the front surface thereof. In another of its aspects, the invention relates to a lamp body incorporating optical elements on a rear surface and a front surface thereof, in combination with lens elements to form indicator lamps.  
           [0003]    2. Description of the Related Art  
           [0004]    Prior art lamp assemblies come in many forms for use in vehicles, such as the combination brake/indicator lights  10  or center high-mount stop lamp (CHMSL)  20  illustrated on the vehicle  5  in FIG. 1. Referring to FIG. 2, a known form of lamp includes a hollow lamp housing  10  having one or a number of cavities  12  therein, often parabolic in nature and having a reflective coating applied thereon, and having an aperture  14  at a rear portion thereof for inserting a lamp or lamps  16 . The front portion of each of these cavities  12  is covered by translucent lens  18  of a selected color corresponding to the indicator lamp enclosed thereby (i.e., red for braking, amber for turning, white for reverse). Each of the lamps  16  inserted into an aperture  14  in the lamp housing  10  is electrically connected to the electrical system of the vehicle  5 , often by a Medusa-like wire harness  17 . Other embodiments include the use of printed circuit boards having a number of light-emitting diodes (LED) secured thereto, the printed circuit board then being enclosed in a housing having a translucent lens thereon.  
           [0005]    Presently, center high-mount stop lamps using light-emitting diodes are comprised of a number of individual assembled components: housings, lenses, gaskets, printed circuit boards, fresnel lenses, wire harnesses, connectors and grommets. Light-emitting diodes as used in the center high-mount stop lamps and other tail lamps have the further disadvantage of presenting a “hotspot” centered over the light-emitting diode due to the directional nature of the diode, as compared to the substantially omnidirectional nature of a conventional incandescent lamp.  
           [0006]    It would be advantageous to reduce the number of components necessary to construct a lamp assembly, and to overcome the other disadvantages of the light-emitting diode design such as the “hot spot” centered on the LED.  
         SUMMARY OF THE INVENTION  
         [0007]    The invention comprises a solid piece of injection-molded plastic having a flat front surface and a rear surface that includes at least one convex parabolic portion having an axis perpendicular to the front surface. A substantially cylindrical cavity is formed in the solid piece of plastic sharing a common axis with the parabolic portion. The bottom surface of the cavity is conical and centered in the cavity with the apex of the cone directed away from the flat front surface. In one embodiment, metallic particles are deposited on the parabolic portion and on the surface of the cone in the bottom of the cavity. A lamp, such as a light-emitting diode, is inserted in the cavity so that it directs light at the cone in the bottom of the cavity. This light is reflected by the metallic deposit on the cone into the transparent material surrounding the cavity. The light is then reflected within the transparent material from the parabolic reflective surface so that it is directed toward the flat front surface and emerges from the solid piece of injection-molded plastic substantially perpendicular to the flat front surface. The rear surface will also include a rib or other obstruction to form a discontinuity in the deposit of the metallic particles to effectively create electrically isolated portions of the metallic deposit that can serve as circuit legs for electrically connecting the light-emitting diode to a power source. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0008]    In the drawings:  
         [0009]    [0009]FIG. 1 is a perspective of view of a vehicle displaying a number of combination brake/indicator lamps and a CHMSL;  
         [0010]    [0010]FIG. 2 is an exploded perspective of view of a prior art combination brake/indicator lamp;  
         [0011]    [0011]FIG. 3 is a perspective view of a vehicular lamp body according to the invention;  
         [0012]    [0012]FIG. 4 is a conceptual view of direct metallization of a copper deposit onto the lamp body of FIG. 3;  
         [0013]    [0013]FIG. 5 is a perspective view of the lamp body of FIG. 3 with a copper coating applied by direct metallization;  
         [0014]    [0014]FIG. 6 is a rear view of a unitary vehicular lamp assembly according to the invention incorporating the lamp body of FIGS.  3 - 5 ;  
         [0015]    [0015]FIG. 7 is a plan view of the unitary vehicular lamp assembly of FIG. 6;  
         [0016]    [0016]FIG. 8 is a cross-sectional view taken through line  8 - 8  of FIG. 6;  
         [0017]    [0017]FIG. 9 is a cross-sectional view taken through line  9 - 9  of FIG. 6;  
         [0018]    [0018]FIG. 10 is a cross-sectional view taken through line  10 - 10  of FIG. 6;  
         [0019]    [0019]FIG. 11 is a rear view of the unitary vehicular lamp assembly according to the invention, highlighting the circuit traces electrically connecting the light-emitting diodes of the assembly;  
         [0020]    [0020]FIG. 12 is a circuit diagram representing the circuit traces of FIG. 11;  
         [0021]    [0021]FIG. 13 is a cross-sectional view of a further embodiment of the invention;  
         [0022]    [0022]FIG. 14 is a perspective view of the embodiment of FIG. 13;  
         [0023]    [0023]FIG. 15 is a cross-sectional view of a further embodiment of the invention;  
         [0024]    [0024]FIG. 16 is a cross-sectional view of a further embodiment of the invention;  
         [0025]    [0025]FIG. 17 is a cross-sectional view of a further embodiment of the invention;  
         [0026]    [0026]FIG. 18 is an exploded perspective view of a further embodiment of a unitary vehicular lamp assembly according to the invention; and  
         [0027]    [0027]FIG. 19 is a perspective view of the embodiment of FIG. 18. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0028]    Referring now to FIGS. 3 and 6, a vehicular lamp assembly according to the invention comprises a solid injection-molded body  102  constructed of a transparent or translucent plastic material. The body  102 , in the preferred embodiment, is elongate having a first end  106  comprising a mounting flange  110  and a second end  108  comprising a mounting flange  112 , and a first substantially flat face  118  and a second contoured face  120 . The first and second faces  118 , 120  are joined by first and second edges  114 ,  116  substantially perpendicular to first face  118 . In the preferred embodiment, the plastic material of the body  102  is described as clear for maximizing the transmission of light therethrough, although it is anticipated that the plastic material can be tinted to affect transmission of light of the chosen color or intensity.  
         [0029]    After formation of the body  102  by injection molding, a material having reflective properties is applied to the second face  120  of the body  102 , the material also having electrically conductive properties. An example of a process suitable for accomplishing this is shown in the U.S. provisional application No. 60/262,502, filed Jan. 18, 2001, commonly owned, entitled METHOD FOR VACUUM DEPOSITION OF CIRCUITRY ONTO A THERMOPLASTIC MATERIAL AND A VEHICULAR LAMP HOUSING INCORPORATING THE SAME, which is incorporated herein by reference in its entirety. Referring to FIGS. 4 and 5, and as further disclosed in the aforementioned provisional application, the body  102  is placed in a vacuum metallization chamber including a target  350  emitting a stream of metallic particles for deposit on second face  120 . Referring to FIG. 6, mounting flanges  110 ,  112  do not receive a metallic deposit, being outside a direct metallization mask boundary  126  which defines the limit of the body  102  exposed to direct metallization.  
         [0030]    Referring now to FIGS.  6 - 8 , the unitary vehicular lamp assembly  100  comprising injection-molded body  102  has a substantially planar first face  118  and a contoured second face  120 . The second face  120  comprises a plurality of convex parabolic surface portions  122  and a number of ribs  130 ,  132 ,  134 ,  136 ,  138 ,  140 ,  142 ,  144 ,  146  projecting from second face  120  beyond the parabolic surface portions  122 , interrupting the continuity of the parabolic surface portions  122  on the second face  120 .  
         [0031]    The body  102  is further molded with a plurality of substantially cylindrical cavities  170 ,  180 ,  190 ,  200 ,  210 ,  220  opening to the contoured second face  120  of the body  120  perpendicular to first face  118 , each of the cavities  170 - 220  centered on the primary axis of a parabola defined by parabolic surface portions  122  of the second face  120 .  
         [0032]    Referring to FIG. 9, cavity  220  is illustrated as an example of each of the cavities  170 - 220  and comprises a substantially cylindrical wall  222  and a conical floor surface  224 , the right cone defined thereby being centered in the cylindrical cavity  220  and sharing a central axis  228  with the parabola defined by the parabolic surface portions  122  surrounding the cavity  220 . As can be seen in FIG. 9, a metallic deposit  226  covers the conical floor  224  of cavity  220 . Following the example of FIGS. 4 and 5 of a method to apply a metallic coating to second face  120  of body  102 , as the body  102  is subjected to the stream of metallic particles that deposits a metallic coating  124  to the parabolic surface portions  122 , the same metallic particles pass into the open cavity  220  and leave a metallic deposit  226  on the conical floor  224  of cavity  220 . The cylindrical wall  222  of cavity  220  does not receive a metallic deposit as the stream of metallic particles is substantially parallel to the wall  222 . Is also anticipated that masking techniques can be employed to insure that no particles are deposited on the sidewalls  222  of cavity  220 .  
         [0033]    With further reference to FIG. 9, a light-emitting diode assembly  250  is inserted into cavity  220 , centered along cavity centerline  228  with light-emitting diode  252  directed toward conical bottom surface  224  of cavity  220 . Light-emitting diode assembly  250  includes first and second leads  254 ,  256  electrically connected to the deposit  124  on the parabolic surface portions  122  by contacts  258 ,  260 . Light emitted by light-emitting diode  252  directly to the conical floor  224  is illustrated as arrow  270 , having an angle of incidence  272 . The reflected light  274  refracts slightly as the light  276  enters the body  102 . The refracted light  276  strikes the parabolic portion  122  at second angle of incidence  278  and reflects off the deposit  124  on the parabolic portion  122 . This reflected light  280  and travels to front flat portion  118  of body  102  to become transmitted light  282  as it exits body portion  102 .  
         [0034]    Referring to FIG. 10, rib  138  has received an incidental metallic deposit  154  on an upper surface  148  subjected to the stream of metallic particles, but rib side surfaces  150  have received no metallic deposit. The metallic deposits  124  on the parabolic surface portions  122  on each side of rib  138  are thereby electrically isolated by the discontinuity of the metallic deposit caused by the presence of rib  138 . It is further anticipated that this electrical isolation can be accomplished by masking during a metallization process.  
         [0035]    Referring again to FIG. 6, it can be seen that the parabolic surface portions  122  surrounding each of the cavities  170 - 220  are separated along a centerline of the body  102  by the ribs  130 ,  132 ,  134 ,  136 ,  138 ,  140 ,  142 ,  144 ,  146 . Specifically, the parabolic surface portions  122  surrounding cavity  170  are divided along a centerline of the body  102  by ribs  130 ,  132 ; the parabolic surface portions  122  surrounding cavity  180  are separated by ribs  132 ,  134 ; the parabolic surface portions  122  surrounding cavity  190  are separated by ribs from 136, 138; the parabolic surface portions  122  surrounding cavity  200  are separated by ribs  138 ,  140 ; the parabolic surface portions  122  surrounding cavity  210  are separated by ribs  142 ,  144 ; and the parabolic surface portions  122  surrounding cavity  220  are separated by ribs  144 ,  146 . The parabolic surface portions  122  surrounding adjacent cavities are not separated by a rib  130 - 146  and the metallic deposit  124  on these parabolic circuit portions  122  is therefore electrically continuous.  
         [0036]    Ribs  134 ,  136 ,  140 ,  142  are not fully contained on the centerline of the body  102  but run from the centerline to a respective edge  114 ,  116  of the body  102 . The parabolic surface portions  122  on a given side of the centerline adjacent to cavity  180  is thereby isolated from the parabolic surface portions  122  adjacent to cavity  190  on the same side of the centerline. The parabolic surface portions  122  between cavity  180  and edge  116  are rather continuous with the parabolic surface portions  122  between cavity  190  and opposing edge  118  on the opposite side of the centerline of body  102  through an interstitial space  152  between rib  134  and rib  136 . The ribs  140 ,  142  between cavities  200 ,  210  are likewise arranged to provide a “crossing-over” of the connection between the parabolic surface portions  122  surrounding the adjacent cavities  200 ,  210 .  
         [0037]    Referring to FIGS. 11 and 12, the interstitial spaces  152  between ribs  134 ,  136  and ribs  140 ,  142 , respectively, join the parabolic surface portions  122  surrounding the adjacent cavities to create “S”-shaped circuit legs  302  and  304  respectively. A power source  320 , such as a vehicle&#39;s political system, is connected at a first end to circuit leg  300  comprising parabolic surface portions  122  adjacent a first side of cavities  170 ,  180 . Circuit leg  302  electrically connects the parabolic surface portions  122  of a second side of cavities  170 ,  180  with the parabolic surface portions  122  of a first side of cavities  190 ,  200 . Circuit leg  304  likewise connects cavities  190 ,  200  with cavities  210 ,  220  and circuit leg  306  connects cavities  210 ,  220  to a ground of power source  320 . This circuit arrangement is given as an example of how circuits can be arranged on a rear surface of a lamp assembly to interconnect a plurality of lamps installed in the assembly.  
         [0038]    Referring now to FIGS.  13 - 18 , further embodiments of the invention are disclosed. In FIGS.  13 - 14 , body  402  includes optical elements  417  such as a fresnel lens formed in front face  418 . Light is transmitted from the light-emitting diode  252 , reflected off the coating  226  on the conical base  224  of the cavity  220  and the coating  124  on the rear surface of the body  402 . The light is further modified by passing through the optical elements  417  formed in front face  418  of body  402 .  
         [0039]    A further embodiment is disclosed in FIG. 15 wherein a coating  524  deposited on a rear surface  522  of a body  502  performs primarily as an electrical circuit with only incidental reflective performance in directing light from an LED  252  through optical elements  517  such as a fresnel lens on front surface  518  of body  502 . Referring to FIG. 16, a further embodiment of the invention includes the embodiment of FIG. 15 further incorporated into a lamp assembly including a lens  530 . Lens  530  is anticipated as having coloration for serving indicator functions, such as making brake lights red or turn signals amber, or containing other optical properties such as diffusion.  
         [0040]    A further embodiment is disclosed in FIG. 17, wherein the embodiment of FIG. 9 is combined in a lamp assembly with a lens  530 .  
         [0041]    Referring to FIGS.  18 - 19 , a further embodiment of a tail lamp assembly  600  is disclosed in an exploded form to show the elements of the assembly  600  and the circuits formed in a deposit  622  to be applied to a rear surface of body  602 . Tail lamp assembly  600  comprises body  602 , a lens  630 , a deposit  622 , a plurality of light-emitting diodes  250  and a conformal seal coating  650 . Body  602  includes a front face of  618  with a plurality of optical elements  617  formed over a corresponding plurality of cavities, each cavity for receiving a light-emitting diode  250  as disclosed in the previous embodiments. Deposit  622  is applied to a rear surface of body  602  so as to form an arrangement of circuits interconnecting the cavities formed in the body  602 . Light-emitting diodes  250  are inserted in the cavities of body  602  and electrically connected to the deposits  622  on the rear surface of body  602 . A conformal coating  650  is anticipated for use to protect the deposit  622  on the rear surface of body  602  from moisture and physical damage, and to electrically insulate it from surrounding components in a vehicle. FIG. 19 illustrates the assembled tail lamp assembly  600  with the optical elements  617  and deposit  622  shown in phantom. It is further anticipated that the embodiment of FIGS.  18 - 19  can be formed with a flat front face  618  of body  602  without optical elements  617 . Is further anticipated that the body  602  can be formed with a flat rear surface, or with a contoured rear surface and cavities having a conical base for taking advantage of the reflective properties of the deposit  622  on the rear surface of body  602 .  
         [0042]    While the invention has been specifically described in connection with certain specific embodiments thereof, it is to be understood that this is by way of illustration and not of limitation, and the scope of the appended claims should be construed as broadly as the prior art will permit.