Vehicle LED lamp having recirculating air channels

Abstract

Lamp module 32 contains solid-state light source 17 and has mounting flange 42 coupleable to headlamp reflector 12. Lamp module 32 has base 2 defining central post 4, post 4 defining internal first air passage 401. Base and post act are heat sinks. Fan 8 is disposed within base 2. Circuit board 14 having LED arrays 17 is mounted inside post 4 in fluid communication with first air passage 401. Base 2 defines second air flow passage 405 exterior of post 4, second air passage 405 being oriented to direct air past mounting flange 42. Base 2 further defines third air passage 410 rearward of mounting flange 42 and radially outward from second air passage 405. Mounting flange 42 may be keys coupleable to slots 15. A method of directing an air stream through slots 15 in reflector socket 121 is described.

Claims

1. An automotive solid-state lamp module (32), comprising: a base (2) defining a central post (4) having an outer peripheral surface (44), the post defining an internal first air flow passage (401) in an interior of the post, a circuit board (14) bearing at least one solid-state light source (17); the post (4) defining a mounting surface for the circuit board (14) bearing the at least one solid-state light source (17); a mounting flange (42) disposed on the base (2), the mounting flange configured to be coupleable to a lamp-receiving reflector socket (121) of a reflector (12); the base (2) further defining at least one exterior second air flow passage (405) exteriorly adjacent the post (4), the second air flow passage (405) being oriented to direct air exiting the second air flow passage past the mounting flange (42) and adjacent the post outer peripheral surface (44); the base (2) further defining a third air flow passage (410) having an air outlet disposed axially rearward of the mounting flange (42) and radially outward from the second air flow passage (405); and an air-moving fan (8) disposed in the base (2) arranged to, when energized, move air to the first, second and third air flow passages (401, 405, 410); wherein a post interior surface defines a first datum surface (403) and a second datum surface (402), the first datum surface (403) abutting an edge (140) of the circuit board (14) and the second datum surface (402) abutting a locator feature (13) on the circuit board (14).

2. The lamp module (32) of claim 1, further comprising a gasket (64) surrounding the post (4) and disposed in an axial direction away from the mounting flange (42); and wherein the second air flow passage (405) is disposed radially inward of the gasket (64).

3. The lamp module (32) of claim 2, wherein the gasket (64) surrounds the second air flow passage (405).

4. The lamp module (32) of claim 1, wherein the second air flow passage (405) comprises a plurality of passages.

5. The lamp module (32) of claim 3, wherein the second air flow passage (405) comprises a plurality of passages.

6. The lamp module (32) of claim 1, wherein the base (2) is formed of thermally conductive material forming a heat sink.

7. The lamp module (32) of claim 1, wherein the mounting flange (42) comprises a plurality of radially extending keys.

8. An automotive solid-state lamp module (32) adapted to be selectively secured to a reflector (12) having a lamp-receiving socket (121), said lamp module in combination with the reflector (12) disposed in a headlamp housing (601) forming a headlamp assembly (6), said lamp module comprising: a base (2) defining a central post (4) having an outer peripheral surface (44), the post defining an internal first air flow passage (401) in an interior of the post, a circuit board (14) bearing at least one solid-state light source (17); the post (4) defining a mounting surface for the circuit board (14) bearing the at least one solid-state light source (17); a mounting flange (42) disposed on the base (2), the mounting flange configured to be coupleable to the reflector socket (121); the base (2) further defining at least one exterior second air flow passage (405) exteriorly adjacent the post (4), the second air flow passage (405) being oriented to direct air exiting the second air flow passage past the mounting flange (42) and adjacent the post outer peripheral surface (44); the base (2) further defining a third air flow passage (410) having an air outlet disposed axially rearward of the mounting flange (42) and radially outward from the second air flow passage (405); and an air-moving fan (8) disposed in the base (2) arranged to, when energized, move air to the first, second and third air flow passages (401, 405, 410); wherein the first air flow passage (401) and the second air flow passage (405) direct air received from the fan (8) into an interior (122) within the reflector (12); and the third air flow passage (410) directs air received from the fan (8) towards an exterior region (123) rearward of the reflector (12).

9. The headlamp assembly of claim 8, further comprises an end cap (602) attached to the headlamp housing (601) rearward of the reflector (12) and in overlying relation to the base (2) of the lamp module (32).

10. A method of cooling a solid-state vehicle lamp module (32) retained in a vehicle headlamp reflector (12), comprising inserting a lamp module (32) having a solid-state light source (17) into a reflector interior (122) of a vehicle headlamp reflector (12) having a lamp-receiving socket (121) configured to receive the lamp module (32), the reflector (12) defining adjacent the socket (121) a plurality of circumferentially disposed slots (15); latching the lamp module (32) to the headlamp reflector (12); directing a first flow of air (F1) from an exterior region (123) exterior the reflector (12) through the lamp module (32) and adjacent the solid-state light source (17); directing a second flow of air (F2) from the exterior region (123) exterior the reflector (12) through the lamp module (32) and through the plurality of slots (15) and thereby into the reflector interior (122); and directing a third flow of air (F3) from the lamp module (32) away from the reflector interior (122) to the exterior region (123) exterior the reflector (12).

11. A method of cooling a solid-state vehicle lamp module (32) retained in a vehicle headlamp reflector (12), comprising inserting a lamp module (32) having a solid-state light source (17) into a reflector interior (122) of a vehicle headlamp reflector (12) having a lamp-receiving socket (121) configured to receive the lamp module (32), the reflector (12) defining adjacent the socket (121) a plurality of circumferentially disposed slots (15); latching the lamp module (32) to the headlamp reflector (12); directing a first flow of air (F1) from an exterior region (123) exterior the reflector (12) through the lamp module (32) and adjacent the solid-state light source (17); directing a second flow of air (F2) from the exterior region (123) exterior the reflector (12) through the lamp module (32) and through the plurality of slots (15) and thereby into the reflector interior (122); and directing a third flow of air (F3) from the lamp module (32) rearward of the reflector (12) thereby bypassing the reflector interior (122).

12. The method of claim 10, further comprising spatially separating the third flow of air (F3) from the second flow of air (F2) by a barrier (64).

13. The method of claim 10, wherein the latching comprises rotating the lamp module (32) relative the plurality of slots (15).

14. The method of claim 10, wherein a principal direction of the second flow of air (F2) is directed laterally displaced from the first flow of air (F1).

Description

BRIEF DESCRIPTION OF FIGURES

(1) The above-mentioned and other features of this disclosure, and the manner of attaining them, will become more apparent and better understood by reference to the following description of embodiments described herein taken in conjunction with the accompanying drawings, wherein:

(2) FIG. 1 is a top perspective view of lamp module 32 showing three air flows;

(3) FIG. 2 is a side elevational of lamp module 32;

(4) FIG. 3 is a front exploded perspective view of lamp module 32;

(5) FIG. 4 is a rear exploded perspective view of lamp module 32;

(6) FIG. 5 is a side exploded view of lamp module 32;

(7) FIG. 6 is a front elevational view of lamp module 32 with section B-B;

(8) FIG. 7 is a sectional view along B-B of FIG. 6;

(9) FIG. 8 is a front elevational view of lamp module 32 with section C-C;

(10) FIG. 9 is a sectional view along C-C of FIG. 8;

(11) FIG. 10 is partly diagrammatic view of lamp module 32;

(12) FIG. 11 is a top diagrammatic view of lamp module 32 coupled to reflector 12;

(13) FIG. 12 is a front schematic of lamp module 32 mounted in headlamp 6 showing air passageways 401, 405 and 410;

(14) FIG. 13 is a side schematic of lamp module 32 mounted in headlamp 6; and

(15) FIG. 14 is a schematic view of lamp module 32 in headlamp 6 showing air flows F1, F2 and F3.

DETAILED DESCRIPTION INCLUDING BEST MODE OF A PREFERRED EMBODIMENT

(16) It may be appreciated that the present disclosure is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the drawings. The embodiments herein may be capable of being practiced or being carried out in various ways. Also, it may be appreciated that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting as such may be understood by one of skill in the art.

(17) The automotive headlamp 6 disclosed herein is suitable for use on a motor vehicle, particularly in the reflector cavity for the vehicle forward lighting such as the vehicle headlamp or fog lamp (collectively be referred to herein as a vehicle headlamp) which is used to illuminate a road surface. The type of motor vehicle may include, but is not limited to, a land vehicle such as a passenger sedan, a sport utility vehicle, a minivan, a truck (light or heavy truck) and a recreational vehicle (e.g., ATV, motorcycle, snowmobile). Alternatively the motor vehicle may also include water vehicles (e.g. boats, jet-skis, personal water craft) and air vehicles (e.g. planes, helicopters).

(18) Referring to FIGS. 1-5, solid-state lamp module 32 has a housing base 2 formed of thermally conductive material, such as metal, e.g. cast aluminum, in order that base 2 also act as a heat sink. Within base cavity 201 in base 2 is accommodated a fan 8 which, when energized, forces air flow. Also disposed within base 2 is an LED driver circuit board 10 having a drive circuit with suitable electrical connections and traces (not shown) as is known in the art. Driver circuit board 10 is formed with central apertures so air driven by fan 8 passes therethrough into an interior cavity 201 of base 2. Fan 8 may contain a Sunon electric fan, e.g. model MF40101VX-1000U-A99, available from Sunonwealth Electric Machine Indus. Co., Ltd. (Taiwan) which exhibits a maximum air flow of 9.9 CFM (280 liters/min) at zero static pressure. Fan 8 can be accommodated in base 2 sized to have an overall diameter at its widest of about 60 mm and a depth of base 2 in an axial direction from the rear to the seating surface of gasket 64 of about 24 mm. An air inlet side 81 of fan 8 is seen in FIG. 4 in that air is drawn from an environment external of, and generally axially rearward of, lamp module 32 up into fan 8 and expelled, as seen in FIG. 4, in an axially forward direction, up and into an internal cavity in base 2.

(19) Lamp module 32 is sized to substitute for a conventional halogen incandescent filament H11 lamp into its conventional headlamp reflector 12 whose socket 121 has a neck having three radial slots 15 to receive mounting flanges of the lamp module and retain it by the conventional insert, twist and lock mounting known in the art.

(20) The base 2 also receives LED-bearing printed circuit board (PCB) 14. PCB 14 is preferably a metal-core PCB (MCPCB). PCB 14 contains solid-state light sources 17, such as light-emitting diodes (LEDs) 17. A first array of LEDs 17, e.g. a 14 array, is connected on the first side of PCB 14 and a second similar array of LEDs 17 on the opposite side of PCB 14. The two arrays of LEDs 17 are arranged back-to-back. The overall width dimension of the two back-to-back arrays of LEDs, to the outermost surfaces of the LEDs, as seen in FIG. 2 or FIG. 7, is about 1.9 mm, thus approximating the thickness dimension of a conventional filament, and facilitating lamp module 32 to be retrofit to an existing reflector 12 designed for a conventional incandescent headlamp.

(21) An MCPCB is usually placed against a heat sink to add in cooling. PCB 14 also bears two thermal heat dissipation pads 18 as is known in the art. Heat dissipation pads 18 can be provided as surface mount technology (SMT) copper pads that are soldered to PCB 14. These structures can be ribbed or formed in some suitable manner to enlarge the surface area and for stiffening. PCB 14 has electrical traces (not shown) to supply power to LEDs 17. PCB 14 has, connected to the electrical traces, an electrical connector 19 to mate with electrical receptacle 102 on driver circuit board 10. Driver circuit board 10 also has input receptacle 101 to make electrical connection with the vehicle chassis electrical supply, which is typically around 9V to 16V, commonly about 12V. Driver circuit board 10 has, as is known in the art, a constant current driver (not shown) to drive LEDs 17 for well controlled lumen output from 11V to 14V.

(22) Base 2 has retaining keys 42 projecting radially outward from outer peripheral surface 44. The peripheral surface 44 acts as a radial locating surface, and peripheral surface 44 is configured for radially fitting into the bore of socket 121 of reflector 12, all in a manner as well known in the art and described hereinabove with regard to the Coushaine U.S. Pat. No. 5,855,430 herein incorporated in its entirety by reference. Locating surface 44 is formed on an outer peripheral surface of partially hollow projection or post 4.

(23) Post 4 projects upward from base 2. Hollow post 4 communicates with base interior cavity 201. An interior of post has one or more grooves defining a first air flow passage 401. Preferably there are two first air flow passages 401 on half of post 4. A portion of post 4 is formed as a removable post cap 500. PCB 14 is clamped to a mounting surface on post 4 by post cap 500 and secured by a fastener 502, such as a screw, extending through a fastener hole (which provides adequate clearance) in PCB 14 and into post 4. On an interior of post cap 500 are formed one or more grooves defining an additional first air flow passage 401, preferably two such first air passages 401. In total there are four first air flow passages 401 on the fully assembled post 4. The first air flow passages 401 direct air principally past LEDs 17 and heat dissipation pads 18 on both sides of PCB 14. Fastener 502 can be formed as a machine screw, self-tapping screw, bolt or the like. Base 2, post 4 and post cap 500 are formed of heat-conductive material, such as metal, e.g. an aluminum. First air channels 401 can be sized relatively compact because post 4 also helps conduct heat away from PCB 14 towards base 2. Referring to FIG. 1, air exiting flow passages 401 exhibits a flow pattern generally as indicated as first air flow F1.

(24) Post 4 and base 2 can be manufactured as a one-piece casting (as shown in FIG. 8), such as from a cast aluminum alloy, and then features formed as necessary by secondary machining operations. Alternatively, post 4 and base 2 are formed as two separate parts and then screwed or staked together to form an integral assembly of post 4 and base 2. Further alternatively, a one-piece casting as discussed for post 4 and base 2 could be modified to cast base 2 and post 4 along with post cap 500 as a one-piece casting divided along a centerline into right-side and left-side portions (not shown), such as right- and left-halves, which are then screwed together to sandwich PCB 14.

(25) Surface locating features can be provided on PCB 14 and post 4 in order to accurately position LEDs 14 relative to base 2. The PCB 14 is advantageously positioned against post 4 by having abutment surface 140 formed on an edge of PCB 14 which when assembled contacts datum surface 403 formed on post 4 of base 2. These mating datum surfaces can cooperate with a pin and slot arrangement defined by pin 402 on post 4 cooperating with locator hole 13 in PCB 14. Alternative datum surfaces to a pin and slot are well known to those of skill in the art and could be provided by mating features such as a pin to (not shown) a flat or to two flats.

(26) Referring to FIGS. 6-9, a cross-section on plane B-B of FIG. 6 is shown at FIG. 7, and a cross-section on plane C-C of FIG. 8 is shown at FIG. 9. FIG. 7 illustrates pin 402 of post 4 disposed in locator key or hole 13.

(27) Referring to FIG. 2 and FIG. 6, base 2 has a mounting flange 42, preferably three such mounting flanges 42 as is conventional in the art, whose undersurfaces 40 define a reference plane P. Reference plane P indicates a mounting plane at which lamp module 32 is retained in socket 121 of reflector 12. The dimension Light Center Length (LCL) is determined in the art from a reference plane P axially to the center of the array of LEDs 17, and in an embodiment hereof can advantageously be controlled to 27.250.2 mm such that lamp module 32 serves as an LED substitute for conventional incandescent H11 headlamps in pre-existing conventional reflectors 12 installed in existing vehicle fleets.

(28) Referring to FIGS. 1, 3, 5, 9 and 10, base 2 also has at least one aperture to define a second air flow passage 405. Preferably second air flow passage 405 is formed as a plurality of passages providing plural flow channels, receiving forced air directed by fan 8 through interior cavity 201 and expelling the air along an exterior of post 4. The air outlets of second flow passages 405 are disposed adjacent outer peripheral surface 44 of post 4, and are as well disposed, in an axial direction, below mounting flange structure 42. Referring to FIG. 1, air exiting the second flow passages 405 exhibits a flow pattern generally as indicated as second air flow F2. In an operative condition of lamp module 32 mounted to socket 121 of reflector 12, second air flow passages 405, while they may advantageously be located below a mounting plane P of module 32, do direct air into an interior 122 of reflector 12, see e.g. FIGS. 11, 13 and 14. Gasket 64 is made of resilient material, such as elastomer or silicone, and in assembled position surrounds a transition neck region between heat sink base 2 and post 4 adjacent to post outer peripheral surface 44. As assembled, gasket 64 surrounds second flow passages 405. Gasket 64 has projecting features 65 similar to ribs which can assist in preventing occluding of second flow passages 405.

(29) Referring to FIGS. 1, 3, 5, 9 and 10, base 2 also has at least one aperture to define a third air flow passage 410. Preferably third air flow passage 410 is formed as a plurality of passages providing plural flow channels, receiving forced air directed by fan 8 through interior cavity 201 and expelling the air away from base 2. Third air flow passages 410 are located radially more outward on base 2 than are second air flow passages 405. The air outlets of third flow passages 410 are disposed, in an axial direction, below mounting flange structure 42. The air outlets of third flow passages 410 may advantageously be disposed on a radially outermost region of base 2. Referring to FIG. 1, air exiting the third flow passages 410 exhibits a flow pattern generally as indicated as third air flow F3. In an operative condition of lamp module 32 mounted to socket 121 of reflector 12, third air flow passages 410, are advantageously located well below a mounting plane P of module 32 such that they do not direct air into an interior of reflector 12 but rather direct air rearward of reflector 12 to an exterior region 123 exterior of and behind reflector 12, see e.g. FIGS. 13 and 14.

(30) Referring to FIGS. 11-12, FIG. 11 is an interior view within socket 121 of reflector 12 of lamp module 32 having been aligned into reflector 12 by the three retaining keys 42 on base 2 inserted into the three mating, key-receiving slots 15 on reflector 12 and then turned a quarter turn to look it into reflector 12, as is conventional in the art. Along its reflector interior 122 reflector 12 has optical surface 16, shown in fragmentary view. From the direction of viewing in FIG. 11 from reflector interior 122 (FIG. 12), lamp module 32 and its retaining keys 42 was inserted into slots 15 and then rotated counter-clockwise about its central axis onto the lands or ledges adjacent slots 15, as has been previously described hereinabove. Note that in the orientation of lamp module 32 coupled to reflector 12, second air flow passages 405 communicate into interior 122 of reflector 12 through the key openings or slots 15. Thus, second air flow passages 405 permit air to move from an exterior region 123 exterior of reflector 12 towards the front of reflector 12.

(31) Referring to FIGS. 12-14, in an installed operative position of lamp module 32 in reflector 12, first air passages 401 communicate through post 4 past PCB 14 into reflector interior 122, and second air passages 405 communicate along an outer surface 44 of post 4 into reflector interior 122. The third air passages 410 are directed towards region 123 behind and exterior of reflector 12. Third air passages 410 are also substantially separated by gasket 64, which surrounds second air flow passages 405, from blowing air into an interior of reflector 12. Collectively, air flow passages 401 and air flow passages 405 direct about 30% of the air forced by fan 8 from the back of headlamp 6 to the front of the headlamp. This aspect makes the LED substitute or retrofit lamp module 32 more compatible with a variety of reflectors already installed in vehicles since temperature management of LEDs 17 is then less dependent on the particular geometry of an individual reflector style. Furthermore, this aspect takes advantage of the fact that the front of headlamp 6, such as at headlamp cover lens 600, is generally cooler since it is farther from the hot engine compartment, thus allowing a significant amount of air near lamp module 32 to become cooled and thus preventing air around the heatsink of base 2 from stagnating and becoming too hot to cool module 32 (such as by having insufficient temperature differential from the rear heatsink of base 2 to drive heat transfer). Moreover, this aspect, by directing significant heated air towards cover lens 600, can improve defogging or deicing performance at cover lens 600. This aspect of diving the air flow has the advantage that it prevents the ambient air temperature around LEDs 17 from continually increasing and forming an oven around the base heatsink 2 thus reducing the ability to remove heat from the LEDs 17 as the air would become increasingly hotter. Because air is circulated from the back to the front by going through post 4 and the second air passages 405 in base 2, the performance of lamp module 32 is less dependent on the exact design of reflector 12 and makes lamp module 32 more compatible across a wider range of reflector designs and vehicle models. While not being bound to a particular theory, typically once air is moved from the back to the front of the reflector, the path back to fan 8 is long and circuitous, which permits the air to give up its heat to the cooler surface of cover lens 600 before returning to fan 8.

(32) Referring to FIGS. 12-14, headlamp 6 has housing 601 in which reflector 12 is disposed, and housing 601 supports cover lens 600, having a construction as is known in the art. Air flows F1 and F2, resulting from air forced from the back of the headlamp to the front through first air passages 401 and second air passages 405, respectively, eventually returns towards rear cavity 123 exterior of reflector 12 through conventionally-existing internal ducts, cracks and baffles that make headlamp 6 leaky inside (i.e., without hermetic barrier between interior and exterior regions of reflector 12) such that the air is again available to be drawn into air inlet 81 of fan 8. FIGS. 12-14 also indicate air flow F3, resulting from air exiting at third air passages 410, is directed in region 123 behind and external to reflector 12.

(33) Again referring to FIGS. 12-14, it may in some cases be desired to couple lamp module 32 permanently or semi-permanently to reflector 12 inside headlamp 6 so that it is not a user-serviceable part in the aftermarket. This can be advantageous if it is desired to offer headlamp 6 as a factory-sealed unit. Headlamp 6 having housing 601 can include an end cover 602 that is firmly attached to housing 601 in overlying relation to lamp module 32 rearward of base 2. End cover 602 could be attached by rivets or welding or other techniques intended to be not readily removable. With end cover 602 secured to headlamp housing 601, exterior region 123 external of reflector 12 is more bounded and the heat sink at the rear region of base 2 somewhat more insulated from the hot engine compartment.

(34) In an operative embodiment of lamp module 32, it drew 16 Watt at 12.8V input to provide a steady state luminous flux of 1250 lm10% and with fan 8 energized maintained a maximum temperature below 140 degrees C. at LEDs 17.

(35) While a preferred embodiment of the present disclosure has been described, it should be understood that various changes, adaptations and modifications can be made therein without departing from the spirit of the disclosure and the scope of the appended claims. The scope of the disclosure should, therefore, be determined not with reference to the above description, but instead should be determined with reference to the appended claims along with their full scope of equivalents. Furthermore, it should be understood that the appended claims do not necessarily comprise the broadest scope of the disclosure which the applicant is entitled to claim, or the only manner in which the disclosure may be claimed, or that all recited features are necessary.

(36) The following is a non-limiting list of reference numeral used in the specification: 2 base 4 post 6 headlamp assembly 8 fan 10 driver circuit board 12 reflector 13 locator hole in PCB 14 14 printed circuit board 15 slot 16 inner optical surface of reflector 12 17 LEDs 18 heat dissipation pad 19 connector 32 lamp module 42 mounting flange or key 44 outer peripheral surface 64 gasket 65 gasket ribs 81 air inlet of fan 101 input receptacle 102 electrical receptacle 121 socket of reflector 12 122 interior of reflector 12 123 exterior region 140 edge of circuit board 14 201 interior cavity 401 first air passage 402 pin (second datum surface) 403 first datum surface 405 second air passage 410 third air passage 500 post cap 502 screw or fastener 600 cover lens 601 headlamp housing 602 end cap P mounting plane F1 first air flow F2 second air flow F3 third air flow