Patent Publication Number: US-8529081-B2

Title: Headlamp device with housing providing thermal management

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation-in-part of U.S. patent application Ser. No. 12/766,655 filed Apr. 23, 2010, which is incorporated herein by reference in its entirety. 
    
    
     TECHNICAL FIELD 
     This application relates to circuit boards and, more particularly, to a metal core circuit board modified with conductive pins. 
     BACKGROUND 
     Light emitting diodes (LEDs) are rapidly replacing conventional sources of illumination such as incandescent bulbs. Because an LED is typically a discrete circuit, it is common to mount LEDs on circuit boards so that the LED may receive the appropriate circuit leads. Although LEDs are more efficient than conventional illumination sources, they still emit an appreciable amount of heat during operation. Metal core printed circuit boards are thus used to provide thermal management for mounted LEDs. Such a board would include a conductive core such as aluminum that is coated with a one or more dielectric layers. A printed or lithographed foil layer, such as copper, overlays the dielectric layer. The foil layer forms the electrical leads to couple to the LED. The dielectric layer(s) act to insulate the foil layer and the coupled circuits from the conductive core. Although the core is thus electrically isolated, it is still thermally connected to the LED such that it acts as an adequate heat sink. 
     But conventional metal core board technology is problematic for applications that must pass electrical leads through the board. For example, such a need is present in LED flashlight applications. In that regard, consider the construction of a conventional flashlight—there is an elongated cylindrical battery housing that holds the batteries and allows a user to handle the device. The battery housing connects to a flashlight head that includes a lens or transparent cover held by a bezel. At the base of the bezel is the circuit board holding the LED(s). 
     The circuit board is mounted within the flashlight orthogonally to the optical axis of the lens. However, such a circuit board arrangement then forms a natural barrier to the necessary electrical leads for coupling between the batteries and the board&#39;s printed foil layer (and ultimately to the LED). Conductive pins passing through the circuit board to couple to the printed foil layer need insulation from the metal core in the board to prevent the batteries from shorting out through the resulting conduction in the metal core. But an insulated pin then requires an extra soldering step to couple to the printed foil layer, which increases manufacturing costs. Alternatively, wires can be passed through a gap between the edge of the board and the bezel, which still requires an extra soldering step and requires a bigger installation space. 
     Accordingly, there is a need in the art for metal core circuit board configurations that enable efficient construction and soldering of leads such as conductive pins to pass through the board. 
     SUMMARY 
     In accordance with a first embodiment of the invention, a circuit board assembly is provided that includes: a metal core circuit board having a principal surface for mounted circuits and at least one through hole extending between the principal surface and a backside surface for the metal core circuit board; and an at least one conductive pin, wherein each conductive pin includes a shaft extending through a corresponding through hole and a pin cap abutting the principal surface adjacent the corresponding through hole such that an undercutting for the pin cap circumferentially surrounds the corresponding through hole. 
     In accordance with a second embodiment of the invention, a method of manufacturing a circuit board assembly is provided that includes: providing a circuit board having a through hole at least partially surrounded by solder; inserting a shaft for a conductive pin into the through hole such that a cap for the conductive pin abuts the solder wherein the through hole has a diameter sufficiently exceeding a diameter for shaft such that the shaft is electrically isolated from a metal core for the circuit board, and wherein the cap has an inner undercut portion surrounding the through hole and an outer remaining portion abutting the solder; and heating the solder such that it reflows and electrically couples the pin to a metal foil layer on the circuit board. 
     In accordance with a third embodiment of the invention, a flashlight is provided that includes a flashlight head including a lens held by a bezel; a metal core circuit board secured to the bezel, the circuit board including a light emitting diode (LED) for illumination through the lens; and a battery housing for holding batteries for powering the LED through a conductive path that includes a first conductive pin having a shaft extending through a first through hole in the circuit board, the first conductive pin including a pin cap abutting a principal surface of the circuit board adjacent the first through hole such that an undercutting for the pin cap circumferentially surrounds the first through hole. 
     In accordance with a fourth embodiment of the invention, a headlamp device is provided that includes a light source; and a housing comprising: a first portion comprising a first set of external surfaces adapted to operate as a first heat sink to dissipate heat from within the first portion of the housing, wherein the light source is disposed within the first portion of the housing, a second portion comprising a second set of external surfaces adapted to operate as a second heat sink to dissipate heat from within the second portion of the housing, and wherein substantially all external surfaces of the of housing are adapted to be exposed to ambient air when the headlamp device is in use and are included in the first and second sets of external surfaces. 
     In accordance with a fifth embodiment of the invention, a method of operating a headlamp device comprising a light source, a housing, and a user control is provided that includes operating the user control to turn on the light source which causes the headlamp device to: dissipate heat from within a first portion of the housing by a first set of external surfaces of the first portion of the housing which are adapted to operate as a first heat sink, wherein the light source is disposed within the first portion of the housing, and dissipate heat from within a second portion of the housing by a second set of external surfaces of the second portion of the housing which are adapted to operate as a second heat sink; and wherein substantially all external surfaces of the of housing are adapted to be exposed to ambient air when the headlamp device is in use and are included in the first and second sets of external surfaces. 
     In accordance with a sixth embodiment of the invention, a method is provided that includes assembling a headlamp device comprising: a light source; and a housing comprising: a first portion comprising a first set of external surfaces adapted to operate as a first heat sink to dissipate heat from within the first portion of the housing, wherein the light source is disposed within the first portion of the housing, a second portion comprising a second set of external surfaces adapted to operate as a second heat sink to dissipate heat from within the second portion of the housing, and wherein substantially all external surfaces of the of housing are adapted to be exposed to ambient air when the headlamp device is in use and are included in the first and second sets of external surfaces. 
     The scope of the invention is defined by the claims, which are incorporated into this section by reference. A more complete understanding of embodiments of the present invention will be afforded to those skilled in the art, as well as a realization of additional advantages thereof, by a consideration of the following detailed description of one or more embodiments. Reference will be made to the appended sheets of drawings that will first be described briefly. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         FIG. 1  is a longitudinal cross sectional view of a flashlight including a metal core board transversed by undercut conductive pins in accordance with an embodiment of the invention. 
         FIG. 2  is a cross-sectional view of the metal core board of  FIG. 1  and the associated LED and undercut conductive pins in accordance with an embodiment of the invention. 
         FIG. 3   a  is a cross-sectional view of a conductive pin transecting a metal core board without any undercutting in accordance with an embodiment of the invention. 
         FIG. 3   b  is a close-up cross-sectional view of the through hole and pin junction for  FIG. 3   a  in accordance with an embodiment of the invention. 
         FIG. 3   c  is a close-up cross-sectional view of the through hole and pin junction for  FIG. 2  in accordance with an embodiment of the invention. 
         FIG. 4  is a perspective view of a metal core board and associated LED and undercut conductive pins in accordance with an embodiment of the invention. 
         FIGS. 5-6  are perspective views of a headlamp device implemented with a headlamp assembly in accordance with embodiments of the invention. 
         FIGS. 7-14  are various views of the headlamp assembly of  FIGS. 5-6  in accordance with embodiments of the invention. 
         FIG. 15  is an exploded view of the headlamp device of  FIGS. 5-6  in accordance with an embodiment of the invention. 
         FIGS. 16-17  are exploded views of portions of the headlamp assembly of  FIGS. 5-6  showing the insertion of a metal core board in accordance with embodiments of the invention. 
         FIG. 18  is view of a ratchet mechanism of the headlamp device of  FIGS. 5-6  in accordance with an embodiment of the invention. 
         FIG. 19  is block diagram of various components of the headlamp assembly of  FIGS. 5-6  in accordance with an embodiment of the invention. 
     
    
    
     Embodiments of the present invention and their advantages are best understood by referring to the detailed description that follows. It should be appreciated that like reference numerals are used to identify like elements illustrated in one or more of the figures. 
     DETAILED DESCRIPTION 
     The following metal core circuit board configuration will be discussed with regard to an example flashlight embodiment. However, it will be appreciated that such a configuration can be widely applied to other applications besides flashlights where there is a need to pass conductors through the metal core circuit board to electrically couple to the printed foil layer. Turning now to the drawings,  FIG. 1  shows a longitudinal cross section of a flashlight  100  including a battery housing  105  holding batteries  110 . 
     A flashlight head  115  includes a bezel  120  holding a lens  125  and forming a backing plate  130 . A metal core circuit board  135  mounts to backing plate  130  so that heat from an LED  140  may dissipate as discussed previously. To turn the flashlight on and off, a user activates a switch  145 . With the switch on, current from the batteries flows through one or more conductive pins  150  to the LED. 
     In some embodiments, a single conductive pin  150  is sufficient in that a ground connection to LED  140  is available through an appropriate coupling through the metal core circuit board  135  to bezel  120  and from bezel  120  to battery housing  105  back to batteries  110 . However, a ground connection through a second conductive pin as shown in  FIG. 2  may also be provided. 
     Additional conductive pins may be provided as necessary for coupling control signals or other desired signals to circuits on metal core board  135 . For example,  FIG. 2  illustrates an embodiment in which two conductive pins  150  pass through metal core board  135 . Regardless of the number of desired pins, each pin  150  has a cap  200  and a shaft or body  205 . The diameter of pin shaft  205  is less than a diameter of corresponding through holes  210  in metal core circuit board  135 . For example, in one embodiment pin shaft  205  has a diameter of 40 mil (one-thousandth of an inch) but through hole  210  is 65 mil in diameter. In this fashion, a clearance of approximately 12 mil circumferentially surrounds pin shaft  205  when the shaft is centered in through hole  210  such that pin  150  is electrically isolated from metal core circuit board  135 . 
     Pin cap  200  is circumferentially undercut around pin shaft  205  such that an annular portion  215  on an underside of cap  200  is also electrically isolated from metal core board  135 . To provide an electrical coupling, some portion of cap  200  connects through solder to a foil layer (discussed further with regard to  FIG. 3   c ) on metal core board  135 . Thus, an outer annulus  220  of cap  200  is not undercut to allow this electrical contact. In that regard, one pin  150  may serve as the power source for LED  140  (as coupled through an appropriate lead formed in the foil layer) whereas a remaining pin  150  acts as the ground lead for LED  140 . 
     Note the advantages of such a coupling to LED  140 —no insulation layer or sleeve is necessary for through holes  210 . Although an insulating sleeve is not necessary, metal core circuit board  135  can include such sleeves if desired. For example, consider  FIG. 3   a , which illustrates a conductive pin  300  extending though a metal core circuit board  305  and electrically isolated by a sleeve  310  (rather than just free space) without any undercutting on a lower surface  314  of a pin cap  320 . 
     As seen in the close-up view of  FIG. 3   b , undersurface  314  for a cap  320  on pin  300  is electrically isolated from a metal core  306  in board  305  by a relatively-thin dielectric coating  315 . As discussed previously, such a dielectric layer isolates leads formed in a printed foil layer on metal core boards from the conducting metal core. However, due to the relative thinness of dielectric layer  315  (typically in a range of 1 to 3 mils), there is a considerable risk of shorting through to metal core  306  at an edge  325  of layer  315 . 
     For example, there may be minor defects along edge  325  that allow metal-to-metal contact between cap  320  and metal core  306 . Alternatively, the voltage between cap  320  and core  306  may cause arcing across such short distances. Thus, the mere presence of an insulating sleeve  310  does not provide adequate isolation between cap  320  and core  306  at edge  325  of dielectric layer  315  as compared to embodiments with a circumferential undercutting on the pin cap as discussed with regard to  FIG. 2 . 
     In that regard, consider the cross-sectional view of undercut cap  200  at the junction with dielectric layer edge  325  as seen in  FIG. 3   c . As discussed with regard to  FIG. 2 , cap  200  is undercut in annular region  215  such that only an outer annular non-undercut region  220  has electrical contact with a printed foil layer  330  that overlays dielectric layer  315 . Note that annular undercut region  215  for cap  200  is displaced from dielectric layer  315  by the depth of the undercutting and the thickness of foil layer  330 . 
     In one embodiment, annular undercut region  215  is undercut to a depth of 5 mil. Foil thickness may range from 3 to 5 mil such that the cap lower surface in annular undercut region  215  is displaced from dielectric layer  315  by 8 to 10 mil in such an embodiment. In contrast, as seen in  FIG. 3   b , pin cap  300  without any undercutting is merely isolated from metal core  306  by the (typically 1 to 3 mil) thickness of dielectric layer  315 . Accordingly, the undercutting for pin cap  200  substantially increases the robustness with regard to preventing electrical shorts between the pin and the metal core. 
     A method for manufacturing circuit board  135  with pins  150  will now be discussed. As seen in  FIG. 4 , a solder mask  400  is deposited over the printed foil layer. Mask  400  has annular openings about through holes  210  so that an annular ring of solder/flux paste may be placed around through holes  210  on the foil layer to eventually solder to corresponding outer annular regions  220  of pin cap  200  discussed earlier. Solder/flux paste is also laid down in an appropriate pattern for coupling to LED  140 . The leads within printed foil layer  330  that couple from pins  150  to LED  140  are underneath solder mask  400  in  FIG. 4  and are thus not visible. 
     The solder/flux paste will not only promote fusion but also is adhesive. Thus, when pins  150  and LED  140  are placed onto the solder/flux paste layers, these components will tend to adhere to metal core circuit board  135  before the solder is reflowed in a reflow oven. For illustration purposes, a pin  150  is left unmounted in  FIG. 4 . 
     To assist robotic placement of pins  150  into through holes  210 , solder mask  400  may include one or more fiducials  405 . Despite the presence of fiducials  405 , there is some tolerance with regard to an exact centering of each pin in a corresponding through hole. Thus, it is desirable that the difference between the pin shaft diameter and the through hole diameter accommodate this tolerance. 
     For example, suppose the tolerance is plus or minus 5 mil. If one desires at least a 5 mil separation between the pin shaft and the through hole wall, the through hole diameter should be at least 20 mil greater than the pin shaft diameter to satisfy the desired separation. In general, the diameter difference between the pin shaft and the through hole will depend upon the tolerance provided by the placement method for centering the pins within each through hole upon insertion. 
     After the pins and LED have been placed upon the circuit board, the resulting assembly may be heated in a reflow oven such that the pins and LED are soldered to the foil layer. In that regard, note that the solder ring surrounding through holes  210  in  FIG. 4  overlies a corresponding ring of metal formed in the printed foil layer. As the solder melts in the oven, surface tension will thus tend to further center each pin in its respective through hole. In this fashion, lower tolerances are accommodated with regard to an initial centering of each pin by a robot. 
     It will be appreciated however that although an automated assembly lowers manufacturing costs, the pins could also be placed manually in their corresponding through holes. Referring back to  FIG. 1 , the resulting circuit board assembly may be fastened to the bezel backing plate  130  using, for example, thermally-conductive glue. To enable convenient grasping of metal core circuit board  135  by a robotic arm during assembly, board  135  includes recesses (or through holes)  410  as shown in  FIG. 4 . A robotic aim can thus insert fingers into recesses  410  to move metal core circuit board  135  such as when metal core circuit board  135  is placed into a reflow oven, or when placed into the bezel during later assembly. 
     Referring again to  FIG. 2 , it may observed that to prevent electrical shorts to the metal core beneath the dielectric layer, the undercut portion  215  need merely circumferentially surround the pin shaft and have some sufficient width or lateral extent such as 35 mil. This undercut need not form a circular annulus but such a shape is naturally achieved through a rotating machining process such a lathe to form the undercut. Similarly, the pin cap need not be circular but again such a shape is convenient. Pins  150  may be constructed of a suitable conductive metal such as brass, copper, or aluminum. To aid in the establishment of electrical contact, pins  150  may be gold plated. 
     Although a metal core circuit board construction has been discussed with regard to an example flashlight embodiment, such a construction may be incorporated into other lighting devices as well. For example, in various embodiments, metal core circuit board  135  may be provided in a headlamp device. 
       FIGS. 5-6  are perspective views of a headlamp device  500  implemented with a headlamp assembly  510  in accordance with embodiments of the invention.  FIGS. 7-14  are various views of headlamp assembly  510  in accordance with embodiments of the invention.  FIG. 15  is an exploded view of headlamp device  500  in accordance with an embodiment of the invention.  FIGS. 16-17  are exploded views of portions of headlamp assembly  510  showing the insertion of metal core circuit board  135  in accordance with embodiments of the invention.  FIG. 18  is view of a ratchet mechanism of headlamp device  500  in accordance with an embodiment of the invention.  FIG. 19  is block diagram of various components of headlamp assembly  510  in accordance with an embodiment of the invention. 
     In various embodiments, headlamp device  500  may be implemented to provide thermal (e.g., heat) management in which heat is dissipated in a generally forward direction and/or away from the user&#39;s head. In this regard, headlamp assembly  510  may be implemented with a housing comprising two portions (e.g., first and second housing portions, such as a front housing portion  530  and a rear housing portion  550 ), each of which may operate as a heat sink to dissipate heat and provide cooling for various portions of headlamp assembly  510 . Front housing portion  530  may operate as a heat sink primarily for an optical assembly  502  (e.g., including metal core circuit board  135 , LED  140 , one or more pins  150 , and/or other components), a charge port  567 , an indicator  576 , and/or other components generally located within front housing portion  530 . Rear housing portion  550  may operate as a heat sink primarily for a main circuit board  570 , a battery  572 , and/or other components generally located within rear housing portion  550 . 
     In one embodiment, front housing portion  530  and rear housing portion  550  may have little or no direct contact with each other. For example, a gasket  563  may be interposed between front housing portion  530  and rear housing portion  550 . As a result, front housing portion  530  and rear housing portion  550  may effectively operate as two separate heat sinks with little heat transfer between them. As a result, heat associated from components disposed within front housing portion  530  may be substantially dissipated by front housing portion  530 , and heat associated from components disposed within rear housing portion  550  may be substantially dissipated by rear housing portion  550 . 
     In various embodiments, front housing portion  530  and rear housing portion  550  may be implemented using a lightweight thermally conductive alloy, magnesium, magnesium alloy, metal, and/or other appropriate heat dissipating materials. Advantageously, substantially all external surfaces of front housing portion  530  and rear housing portion  550  may be exposed to the operating environment (e.g., ambient air) and thus may be used to dissipate heat in a short thermal path from headlamp assembly  510  to the operating environment. For example, front housing portion  530  provides top and bottom surfaces  533  and  535 , respectively, as well as front surfaces  532 , all of which may operate as a heat sink. Similarly, rear housing portion  550  provides top and bottom surfaces  553  and  555 , respectively, as well as rear surface  552 , all of which may operate as a heat sink. In one embodiment, substantially all surfaces provided by front housing portion  530  and rear housing portion  550  may be exposed to the operating environment when headlamp device  500  is in use. Substantially all of such surfaces may be substantially elongated and substantially planar with large surface areas to provide large amounts of active cooling area for heat dissipation through convection and radiation. In one embodiment, front housing portion  530  and rear housing portion  550  may be shaped to maximize the ratio of active cooling surface area to mass, wherein the active cooling surface area of headlamp assembly  510  is the product of the heat transfer coefficient (h) and the combined exposed surface area (A) of front housing portion  530  and rear housing portion  550 . 
     In use, front surfaces  532  may be particularly efficient for dissipating heat and providing cooling for headlamp assembly  510 . In this regard, when the user moves forward while headlamp device  500  is positioned on the user&#39;s head, front surfaces  532  may be pushed forward through the air. As such, front surfaces  532  provide a broad heat sink that receives direct airflow from the ambient air as the user moves forward. As a result, front housing portion  530  may efficiently dissipate heat and provide cooling (e.g., convective cooling) for various components of headlamp assembly  510 . 
     In addition, headlamp assembly  510  may be offset from the user&#39;s head. In this regard, an air gap may be provided between rear surface  552  and the user&#39;s head to reduce the amount of dissipated heat felt by the user. In one embodiment shown in  FIG. 5 , the air gap is identified by arrows  561  which denote the space between rear surface  552  of rear housing  550  and a base  522  of a cradle  521  (e.g., base  522  may be positioned in proximity to the user&#39;s head when a strap  527  is positioned around the user&#39;s head). 
     In one embodiment, the thermal management features provided by front housing portion  530  and rear housing portion  550  permit LED  140  to operate at higher temperatures, and thus higher brightness levels, than conventional headlamps. 
     Various components of headlamp device  500  shown in  FIGS. 5-19  will now be further described. As shown, headlamp assembly  510  includes front housing portion  530 , rear housing portion  550 , optical assembly  502 , a knob assembly  504 , and a pivot assembly  506 . 
     Optical assembly  502  includes an o-ring  560 , a reflector housing  562 , a lens gasket  565 , a lens  566 , a reflector  568  (e.g., a total internal reflection (TIR) reflector), a retaining ring  571 , and metal core circuit board  135 . Optical assembly  502  may be inserted into a recess  534  in front housing portion  530 . Light emitted by LED  140  (e.g., or any other desired type of light source provided on metal core circuit board  135  or otherwise provided) may be projected through reflector  568  and lens  566  toward the front of headlamp assembly  510  generally in the direction of an arrow  589  (see  FIG. 5 ). As discussed, metal core circuit board  135  may be used to dissipate heat associated with LED  140 . For example, metal core circuit board  135  may contact front housing portion  530  and thus may dissipate heat to front housing portion  530  which in turn dissipates the heat to the operating environment. 
     As shown in  FIGS. 16-17 , front housing portion  530  includes apertures  536  which may receive one or more pins  150  protruding in the direction of an arrow  1600 . One or more pin receivers  574  may be provided on main circuit board  570  to receive pins  150  and provide conductive paths from pins  150  to other components on main circuit board  570 . As a result, LED  140  and/or other components on metal core circuit board  135  may receive electrical power (e.g., from battery  572 ) and/or control signals (e.g., from other components on main circuit board  570 ) through such pins  150  while pins  150  remain electrically isolated from metal core circuit board  135  as discussed. 
     In some embodiments, a single pin  150  is sufficient in that a ground connection to LED  140  is available through an appropriate coupling to battery  572  through metal core circuit board  135 , front housing portion  530 , screws  539 , rear housing portion  550 , and main circuit board  570 . In other embodiments, a ground connection through a second conductive pin  150  may also be provided. In other embodiments, additional pins  150  may be provided as desired for coupling control signals or other desired signals between main circuit board  570  and metal core circuit board  135 . 
     Headlamp assembly  510  also includes charge port  567  configured to receive electrical power from an external power source. Charge port  567  may pass such electrical power to main circuit board  570  to charge battery  572  (e.g., where battery  572  is implemented as a rechargeable battery). In another embodiment, battery  572  may be implemented as a non-rechargeable battery. Headlamp assembly  510  also includes a charge port cover  564  which may be used to conceal charge port  567  when not in use. 
     As discussed, headlamp assembly  510  also includes gasket  563  that may be interposed between front housing portion  530  and rear housing portion  550 . In one embodiment, charge port cover  564  may be integrated with gasket  563  as a single structure. 
     As discussed, headlamp assembly  510  also includes main circuit board  570  connected to battery  572 . In this regard, battery  572  may be used to power various components of main circuit board  570  and metal core circuit board  135 . 
     Main circuit board  570  includes indicator  576  (e.g., an LED or other appropriate light source) which may identify the amount of power remaining in battery  572 . In this regard, headlamp assembly  510  may also include a window  540  in bottom surface  535  of front housing portion  530  to permit the user to view indicator  576 . 
     Front housing portion  530  may be joined with rear housing portion  550  through the engagement of screws  539 . In this regard, screws  539  may be inserted through apertures  538  in front housing portion  530 , apertures  569  in gasket  563 , and apertures  558  in rear housing portion  550 . While assembled, front housing portion  530  and rear housing portion  550  may contact complementary sides of gasket  563 ; main circuit board  570 , battery  572 , and a potentiometer circuit board  578  may reside substantially within a cavity  554  of rear housing portion  550 ; and charging port  567 , indicator  576 , and other components of main circuit board  570  may reside substantially within cavities  556  of front housing portion  530 . 
     Knob assembly  504  includes a knob  582 , an o-ring  584 , a lock ring  586 , an o-ring  588 , a potentiometer connector  590 , a spring  592 , and a ball  594 . Knob assembly  504  may be mounted on an extension  583  of rear housing portion  550  having threads to engage with complementary threads of knob  582 . Knob assembly  504  may be used to operate LED  140 . For example, the user may rotate knob  582  to selectively adjust light output by LED  140  (e.g., to selectively turn LED  140  on or off, to selectively change the brightness (e.g., level or intensity) of light emitted by LED  140 , to flash LED  140  in a pattern (e.g., a strobe pattern or other pattern), and/or to perform other adjustments). In one embodiment, rotation of knob  582  may cause potentiometer connector  590  to rotate a potentiometer  579  (see  FIG. 19 ) on potentiometer circuit board  578  which provides appropriate signals to LED  140  and/or other components of main circuit board  570  to operate LED  140  as desired. In other embodiments, other appropriate types of user controls may be provided and used as desired. 
     Pivot assembly  506  includes a pivot screw  595 , a washer  596 , and a ratchet member  598 . Pivot assembly  506  may be mounted on an extension  599  of rear housing portion  550 . Pivot screw  595  includes a slot  591  which may receive a tool (e.g., a screwdriver, fingernail, or other appropriate tool) to tighten pivot assembly  506 . 
     Headlamp device  500  also includes cradle  521  and strap  527  which may be used together to mount headlamp assembly  510  in proximity to the user&#39;s head. In this regard, cradle  521  includes base  522 , support members  523 , apertures  524 , and apertures  525 . Strap  527  may wrap around the user&#39;s head and may be connected to cradle  521  through one or more of apertures  525 . Extensions  583  and  599  of rear housing portion  550  may pass through apertures  524  to permit cradle  521  to hold headlamp assembly  510 . 
     Headlamp device  500  also includes a pad  528  (e.g., made of breathable material with moisture wicking capability, such as BREATHE-O-PRENE® of Accumed Innovative Technologies, LLC, or other appropriate material) which may contact the user&#39;s head when wearing headlamp device  500 . Pad  528  may be connected to base  522  of cradle  521  by a pad attachment  526 . 
     In one embodiment, headlamp assembly  510  may be rotated relative to cradle  521  by a ratchet mechanism shown in  FIG. 18 . Rear housing portion  550  includes an annular surface  597  having teeth  593  disposed around extension  599 . An annular surface  547  of ratchet member  598  facing annular surface  597  includes complementary teeth  543 . When ratchet member  598  is positioned against rear housing portion  550 , teeth  593  may engage with teeth  543  to keep headlamp assembly  510  fixed in position relative to cradle  521 . When the user applies sufficient pressure to dislodge teeth  543  and  593  from each other, headlamp assembly  510  may rotate substantially in the direction of the applied pressure until teeth  543  and  593  reengage with each other. Accordingly, it will be appreciated that headlamp assembly  510  may be selectively ratcheted up or down to rotate optical assembly  502  to any desired position to adjust the angle of light projected by LED  140  in relation to the user&#39;s head. 
     Referring now to the block diagram of  FIG. 19 , various components of headlamp assembly  510  and their associated connections are shown. In addition to components previously discussed herein, headlamp assembly  510  may further include additional components connected to main circuit board  570  such as one or more processors  1910 , one or more memories  1920 , one or more temperature sensors  1960 , one or more temperature management blocks  1970 , one or more switching logic input/output ports  1980 , and one or more other components  1930  (e.g., which may be desired for particular implementations). Also, headlamp assembly  510  may further include one or more other components  1940  (e.g., which may be desired for particular implementations) connected to metal core circuit board  135 . 
     Processor  1910  may execute various instructions stored in memory  1920  or stored on one or more machine readable mediums  1950  (e.g., non-transitory storage mediums on which instructions such as software, microcode, or other instructions may be stored) to perform various operations as may be desired in various implementations. In various embodiments, processor  1910  may be implemented by one or more logic circuits, programmable logic devices (PLDs), general purpose processors, application-specific integrated circuits (ASICs), or other appropriate circuitry. 
     In one embodiment, processor  1910  may operate LED  140  in response to the user&#39;s operation of knob  582  (e.g., which may cause potentiometer  579  to rotate). 
     In one embodiment, processor  1910  may operate LED  140  in response to control signals received by temperature sensor  1960 . In this regard, processor  1910  and temperature sensor  1960  may provide a control circuit to efficiently drive LED  140  to full output levels and reduce the output level of LED  140  in response to control signals provided by temperature sensor  1960  if the temperature of headlamp assembly  510  exceeds a threshold temperature. Temperature management block  1970  (e.g., temperature sensor, digital circuit, analog circuit, and/or other appropriate components) may be used in combination with and/or in place of processor  1910  and/or temperature sensor  1960  to efficiently drive LED  140  as may be desired in particular implementations. 
     In one embodiment, potentiometer  579  and/or potentiometer circuit board  578  may be replaced and/or supplemented by a digital and/or analog output control (e.g., another type of user control or machine control) as may be desired in particular implementations. 
     One or more switching logic input/output ports  1980  may be used to interface with additional controls (e.g., switches or other types of controls that may be provided on a lighting device, such as switches mounted on surfaces, bodies, tailcaps, or other locations) that provide appropriate control signals to main circuit board  570  to support any of the various operations described herein. 
     Although various particular examples of the operation of processor  1910  and other components have been described, any desired features may be implemented by executing appropriate instructions by processor  1910 . Where desired, processor  1910  and appropriate components may be replaced or supplemented with other circuits or components to provide the various operations as desired. 
     Where applicable, various embodiments provided by the disclosure can be implemented using hardware, software, or combinations of hardware and software. Also where applicable, the various hardware components and/or software components set forth herein can be combined into composite components comprising software, hardware, and/or both without departing from the spirit of the disclosure. Where applicable, the various hardware components and/or software components set forth herein can be separated into sub-components comprising software, hardware, or both without departing from the spirit of the disclosure. In addition, where applicable, it is contemplated that software components can be implemented as hardware components, and vice-versa. 
     Software in accordance with the disclosure, such as program code and/or data, can be stored on one or more machine readable mediums. It is also contemplated that software identified herein can be implemented using one or more general purpose or specific purpose computers and/or computer systems, networked and/or otherwise. Where applicable, the ordering of various steps described herein can be changed, combined into composite steps, and/or separated into sub-steps to provide features described herein. 
     Embodiments described above illustrate but do not limit the invention. For example, a manufacturing method was discussed with regard to a reflow soldering process but it will be appreciated that other soldering techniques could be used to connect the pin cap to the board&#39;s printed foil layer. In addition, although flashlight  100  and headlamp device  500  have been discussed, the features described herein may be used with other types of lighting devices as may be desired in particular applications. Also, although LED  140  has been discussed, any desired number or combination of LEDs, filament lamps, arc lamps, or other types of light sources may be used as may be desired in particular applications. Thus, it should also be understood that numerous modifications and variations are possible in accordance with the principles of the present invention. Accordingly, the scope of the invention is defined only by the following claims.