Patent Publication Number: US-9416938-B2

Title: Integrated optic and bezel for flashlight

Description:
TECHNICAL FIELD 
     The present disclosure relates to bezels and lenses for shaping a beam of light from a light source in a flashlight or other lighting unit, and more particularly, to integrated housing members and lens systems for flashlights. 
     BACKGROUND 
     Lenses for flashlights and other lighting units have been provided in a variety of forms, generally having in common a shape that is symmetrical about an axis along which the light is directed, e.g., the optical axis. Several such lenses have included a hole in a rear end of the lens adjacent a light source. Within the hole, the light source may be adjusted in position along the optical axis. Adjustment of the light source&#39;s position relative to the rear hole of the lens enables variance of a light beam emerging from a front face of the lens. Typically, lenses are limited in their capacity to combine a maximum intensity for a spot beam with a substantial uniformity for a wide beam. 
     Such lenses typically also were provided with a central convex lens surface on a front face combined with at least one additional convex surface where the light was either received into the lens, reflected within the lens, or emitted from the lens. Without being bound by theory, the additional convex surface may have been deemed necessary for a proper focusing of light from the source into a beam. Such lenses were alternatively provided with light-receiving, reflecting, and emitting surfaces that were flat as viewed in cross-section. Such flat surfaces were also likely deemed necessary for light-focusing or manufacturing purposes. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Embodiments will be readily understood by the following detailed description in conjunction with the accompanying drawings. Embodiments are illustrated by way of example and not by way of limitation in the figures of the accompanying drawings. 
         FIG. 1  is a cross-sectional view of one example of a lens body that may form a portion of an integrated lens and bezel (front portion of a housing member) system; 
         FIGS. 2A-2C  illustrate cross-sectional views of three examples of thin-profile lens bodies that may form a portion of a lens and bezel (front portion of a housing member) system, including a thin-profile lens having a concave rear surface on the central portion of the lens ( FIG. 2A ), an example having a flat rear surface on the central portion of the lens ( FIG. 2B ), and an example having a convex rear surface on the central portion of the lens ( FIG. 2C ); 
         FIGS. 3A and 3B  are cross-sectional views of a bi-convex lens ( FIG. 3A ) and a bi-concave lens ( FIG. 3B ), either of which may form a portion of an integrated lens and bezel (front portion of a housing member) system; 
         FIG. 4  is a cross-sectional view of another lens that may form a portion of an integrated lens and bezel (front portion of a housing member) system; 
         FIGS. 5A and 5B  show the light refraction and reflection to form varying beams ( FIG. 5B  wide or flood beam and  FIG. 5A  narrow or spot beam) as the light source is moved in the rear well of the exemplary lens body illustrated in  FIG. 1 ; 
         FIGS. 6A-6D  are four cross-sectional views of an integrated bezel (front portion of a housing member) and lens system for a flashlight, showing a threaded adjustable bezel (front portion of housing member) with the light source in a wide beam or flood position ( FIG. 6A ) and a narrow or spot beam position ( FIG. 6B ), and a slidably-adjustable bezel (front portion of housing member) with the light source in a wide beam or flood position ( FIG. 6C ) and in a narrow or spot beam position ( FIG. 6D ); 
         FIGS. 7A and 7B  show two cross-sectional views of fixed-focus flashlights configured for a wide beam ( FIG. 7A ) and a narrow or spot beam ( FIG. 7B ), each having a one-piece integrated lens system, bezel (front portion of housing member), and housing body; and 
         FIGS. 8A and 8B  illustrate two views of an adjustable focus flashlight having a one-piece integrated optics system, bezel (front portion of housing member), and housing body, including cross-sectional views of the flashlight with the light source in a wide beam or flood position ( FIG. 8A ) and with the light source in a narrow beam or spot beam position ( FIG. 8B ), in accordance with various embodiments. 
     
    
    
     DETAILED DESCRIPTION OF DISCLOSED EMBODIMENTS 
     In the following detailed description, reference is made to the accompanying drawings which form a part hereof, and in which are shown by way of illustration embodiments that may be practiced. It is to be understood that other embodiments may be utilized and structural or logical changes may be made without departing from the scope. Therefore, the following detailed description is not to be taken in a limiting sense, and the scope of embodiments is defined by the appended claims and their equivalents. 
     Various operations may be described as multiple discrete operations in turn, in a manner that may be helpful in understanding embodiments; however, the order of description should not be construed to imply that these operations are order dependent. 
     The description may use perspective-based descriptions such as up/down, back/front, and top/bottom. Such descriptions are merely used to facilitate the discussion and are not intended to restrict the application of disclosed embodiments. 
     The terms “coupled” and “connected,” along with their derivatives, may be used. It should be understood that these terms are not intended as synonyms for each other. Rather, in particular embodiments, “connected” may be used to indicate that two or more elements are in direct physical or electrical contact with each other. “Coupled” may mean that two or more elements are in direct physical or electrical contact. However, “coupled” may also mean that two or more elements are not in direct contact with each other, but yet still cooperate or interact with each other. 
     For the purposes of the description, a phrase in the form “NB” or in the form “A and/or B” means (A), (B), or (A and B). For the purposes of the description, a phrase in the form “at least one of A, B, and C” means (A), (B), (C), (A and B), (A and C), (B and C), or (A, B and C). For the purposes of the description, a phrase in the form “(A)B” means (B) or (AB) that is, A is an optional element. 
     The description may use the terms “embodiment” or “embodiments,” which may each refer to one or more of the same or different embodiments. Furthermore, the terms “comprising,” “including,” “having,” and the like, as used with respect to embodiments, are synonymous. 
     Embodiments herein provide one-piece, integrated bezel (e.g., a front portion of a housing member) and lens systems for flashlights and other devices. In some embodiments, the integrated bezel (front portion) and lens system may be combined with a light source and an adjustment mechanism, and it may be incorporated in a flashlight or other lighting unit and provide for focusing the light from the source. In other embodiments, the lens and bezel (front portion) may also be continuous with a body member that forms all or part of a housing for the flashlight. Such one-piece devices may provide a fixed-focus beam, whereas other one-piece devices may include an adjustment mechanism that permits adjustment of the light source relative to the lens, thus focusing the beam between a narrow or spot beam and a wide beam or flood light. In various embodiments, a light emitting diode or LED may be used as the light source, although other light sources, such as incandescent or fluorescent bulbs, may be used. 
     In some embodiments, the bezel (front portion of a housing member) of the flashlight may be continuous with the lens. In various embodiments, any lens suitable for shaping a beam in a desired manner may be used as a part of the integrated lens and bezel (front portion of a housing member) system. For example, in one embodiment the lens may be a one-piece focusing optic with a central focusing element, a side wall and annular ring portion having a thin profile, and a rear void for accommodating a light source. In another embodiment, the lens may be a thin-profile lens having a central focusing element and a thin-profile annular ring portion, and no rear void. Other embodiments may be simple bi-convex or bi-concave lenses. Still other lenses suitable for use as a component of the integrated lens and bezel (front portion of a housing member) system include conventional lenses that may include a front face, a rear LED-receiving void, and a side surface extending between the front face and the rear well. 
     In some embodiments, the system may include an adjustment mechanism for moving the light source relative to the lens or the lens relative to the light source. For example, in some embodiments, the lens may be continuous with the bezel (front portion), which may be adapted to couple to a body member that includes the LED fixed thereupon. In these embodiments, the distance between the lens and the LED may be adjusted by virtue of adjusting the position of the bezel (front portion) on the body member, for instance via a threaded coupling or one or more O-rings. 
     In other embodiments, the lens, bezel (front portion), and body member may be a single, unitary, integrated piece, and the body member may form all or part of a housing adapted to accommodate the LED or other light source. In some embodiments, the LED may be fixed with regard to the lens, and the flashlight may be configured to be a non-adjustable light, such as a wide beam or flood light or a focused beam flashlight. In other embodiments, the LED may be adjustable within the body member or housing, and an adjustment mechanism may be provided on an outside surface of the body member that permits adjustment of the position of the LED with respect to the lens. 
     In various embodiments, the central surface of the lens may be convex, and so may include a forward-most point, typically at the center of the surface. In various embodiments, the annular surface of the front face of the lens body may extend forward to a front rim that is farther forward than the forward-most point of the central surface, thus protecting the lens body from impact and abrasion. The lens body may further include an outer, front rim defining a chamfer between the annular surface and the side surface. In various embodiments, a rim may run around the rear well and the rear well adjacent the rear rim may be provided with a draft angle to facilitate removal from a mold. 
     As described above, a flashlight incorporating the lens system may include a housing structure in one or more portions that include the bezel (front portion of a housing member), and at least the bezel (front portion) may be continuous with the lens. The flashlight also may include an optional adjustment mechanism and an LED. In some embodiments, the lens, the optional adjustment mechanism, and all or part of the housing structure may be a single, integrated piece. 
     In various embodiments, the flashlight also may include a power supply, such as batteries or an AC-DC converter with electronics to condition a voltage waveform compatible with the LED. For example, in some embodiments, a pulse width modulator may be used to adjust the effective brightness of the LED. 
     In various embodiments, the lens body, bezel (front portion), and optionally, all or part of the body or housing may be formed of a single piece of solid, transparent material, such as polymethyl methacrylate (PMMA), molded or otherwise formed as a single piece. In some embodiments, the lens and bezel (front portion), or the lens, bezel (front portion), and all or part of the body or housing may be formed from a single piece of solid, injection-molded acrylic, or another suitable material, such as polycarbonate plastic. In other embodiments, the lens and bezel (front portion), or the lens, bezel (front portion), and all or part of the body or housing may be co-molded. Optionally, some portions of this integrated piece, such as the bezel (front portion) and/or reflector, may be tinted, painted, or coated, for example with a light-reflecting coating or an opaque coating to prevent light escape. 
       FIG. 1  shows one embodiment of a lens  100  that may form a portion of a single-piece, integrated lens and bezel (front portion of a housing member) system. The lens illustrated in  FIG. 1  is described in greater detail in U.S. Provisional patent Ser. No. 13/490,278. Although only the lens  100  is illustrated in  FIG. 1 , it will be understood that lens  100  may form a part of a larger, unitary structure in some embodiments that may include, for example, a bezel (front portion) and optionally a body or housing member. In various embodiments, the lens body  100  may have a generally concave front face  102  and a generally convex rear face  104 . In various embodiments, the lens body  100  may include a central portion  106 , including a central focusing element  110  and a side wall  116 , and an annular ring portion  108  surrounding the central portion  106 . 
     In various embodiments, central portion  106  includes a central focusing element  110 , which may be configured to direct light in a desired direction. In various embodiments, central focusing element  110  may include a convex front surface  112  and a flat rear surface  114 , although in other embodiments, rear surface  114  may be flat or convex, depending on the desired focusing properties of the lens. In various embodiments, central focusing element  110  may be set off from annular ring portion  108  by a side wall  116  that may be configured to form a rear void  118  in the rear face  104  of the lens. In various embodiments, rear void  118  may be sized and shaped to accommodate a light source and/or at least of a portion of the light source base or pedestal (not shown). In various embodiments, side wall  116  may be flat as illustrated in  FIG. 1 , or it may have a slight elliptical curve, depending on the desired focusing properties of lens  100 . Additionally, side wall  118  may have convex, flat, or concave front  120  and back  122  surfaces, as desired in order to achieve the desired light focusing properties. In one specific, non-limiting example, rear void  118  may have a substantially frustoconical shape. 
     In various embodiments, annular ring portion  108  may have a reflective front or back surface, and may be shaped in order to reflect light from the light source in a desired direction. In various embodiments, as described in greater detail below, central focusing element  110 , side wall  116 , and annular ring portion  108  may be configured to cooperate to direct light from a light source in a desired direction. Although a particular configuration of lens components is illustrated in  FIG. 1 , one of skill in the art will appreciate that other combinations of flat and/or curved lens surfaces may be substituted to fit a particular application and/or set of beam focusing requirements. 
     Additionally, although lens body  100  includes slight concavities and/or convexities in various portions, one of skill in the art will appreciate that the overall lens shape includes a generally concave front face  102 , a generally convex rear face  104 , a central focusing element  110 , a side wall  116  configured to form a rear void  118 , and an annular ring portion  108  configured to function as a reflector. Although the illustrated embodiment depicts central focusing element  110  as being continuous with side wall  116 , one of skill in the art will appreciate that in other embodiments these features may be partially or completely discontinuous. In various embodiments, the overall thickness of the lens body  100 , excluding central focusing element  110 , when seen in cross section, is fairly uniform throughout lens body  100 , despite being adapted to bend in and out of plane in order to achieve a desired focusing effect. In various embodiments, the thickness of lens body  100 , excluding central focusing element  110 , may vary less than about 10% over the entire width of lens body  100 . For example, in one specific, non-limiting example, the thickness may vary by less than about 10% over the full width of lens body  100 , excluding central focusing element  110 , for example, 9%, 8%, 7%, 6%, 5%, 4%, 3%, 2%, 1%, or even 0%. In specific, non-limiting embodiments, a suitable lens thickness for a small-diameter lens may be about 2-3 mm, and a suitable thickness for a large-diameter lens may be 2-3 cm, or even more. 
     In various embodiments, central portion  106  may include a convex front surface  112  defining a forward-most point. In various embodiments, convex front surface  112  may incorporate any of various curvatures, and in some embodiments, the curvature may be substantially arcuate with a radius of no more than about 4 mm for a small-diameter flashlight having an overall lens diameter of less than about 2 cm, for example a lens having an overall diameter of about 12 mm. One of skill in the art will appreciate that this central portion diameter may be generally proportionately larger for larger diameter lenses. For example, a large diameter lens of 5-10 cm may have a central portion having a diameter of 1-4 cm, for example about 1.5-2.5 cm. The measurements described with reference to the embodiments of the lens are merely exemplary. Those of ordinary skill in the art will readily understand that other measurements may be used without deviating from the scope of the disclosure. 
     In various embodiments, annular ring portion  108  of lens body  100  may extend forward to front rim  124 . In various embodiments, front rim  124  may extend farther forward than the forward-most point of central portion  106 . In various embodiments, front rim  124  may include a chamfer between annular ring portion  108  and front rim  124  of at least about 0.2-0.5 mm of width for a small diameter flashlight. In some embodiments, the chamfer may have a width selected for a desired lens size and operational characteristics, and, as examples only, may be about 1.5 mm, about 2.0 mm, about 2.5 mm, or about 3.0 mm in width for a larger diameter lens. 
       FIGS. 2A-2C  illustrate cross-sectional views of three examples of thin-profile lens bodies, including a thin-profile lens having a concave rear surface on the central portion of the lens ( FIG. 2A ), an example having a flat rear surface on the central portion of the lens ( FIG. 2B ), and an example having a convex rear surface on the central portion of the lens ( FIG. 2C ), in accordance with various embodiments. The lenses illustrated in  FIGS. 2A-2C  are described in greater detail in U.S. Provisional patent Ser. No. 13/490,275. Although only the lenses  200   a ,  200   b ,  200   c  are illustrated in  FIGS. 2A-2C , it will be understand that lenses  200   a ,  200   b ,  200   c  may form a part of a larger, unitary structure in some embodiments that may include, for example, a bezel (front portion) and optionally a body or housing member. Each lens  200   a ,  200   b ,  200   c  has a generally concave front face  202   a ,  202   b ,  202   c  and a generally convex rear face  204   a ,  204   b ,  204   c . Each of the illustrated lens bodies  200   a ,  200   b ,  200   c  includes a central portion  206   a ,  206   b ,  206   c  and an annular ring portion  208   a ,  208   b ,  208   c  surrounding central portion  206   a ,  206   b ,  206   c . In various embodiments, as described in greater detail below, these different lens portions may be configured to direct light from a light source in a desired direction. Although the illustrated lens bodies are shown as having two distinct light-directing portions, one of skill in the art will recognize that suitable thin-profile lenses also may be configured to have only one, or three, four, or more distinct light-directing portions. 
     In various embodiments, both central portion  206   a ,  206   b ,  206   c  and annular ring portion  208   a ,  208   b ,  208   c  may have a thin profile in cross-section, though both lens portions may have curved or flat front and rear surfaces. For example, in the example illustrated in  FIG. 2A , central portion  206   a  has a convex front surface  214   a  and a concave rear surface  216   a . Annular ring portion  208   a  has a flat front surface  210   a  and a flat rear surface  212   a , and presents a generally flat profile in cross section. 
     In the example illustrated in  FIG. 2B , central portion  206   b  has a convex front surface  214   b  and a flat rear surface  216   b . Annular ring portion  208   b  has a concave front surface  210   b  and a convex rear surface  212   b . As can be seen in  FIG. 2B , annular ring portion  208   b  has a generally curved cross-sectional profile, as compared to the comparatively straight cross-sectional profile  208   a  shown in  FIG. 2A . 
     In the example illustrated in  FIG. 2C , central portion  206   c  has a convex front surface  214   c  and a convex rear surface  216   c . Annular ring portion  208   c  has a concave front surface  210   c  and a flat rear surface  212   c . As can be seen in  FIG. 2C , annular ring portion  208   c  has a slightly curved cross-sectional profile, as compared to the comparatively straight cross-sectional profile  208   a  shown in  FIG. 2A . 
     Although three examples of combinations of lens curvatures are illustrated in  FIGS. 2A, 2B, and 2C , one of skill in the art will appreciate that other combinations of flat and/or curved lens surfaces may be substituted to fit a particular application and/or set of beam focusing requirements. Additionally, although lens bodies  200   a ,  200   b ,  200   c  include slight concavities and/or convexities in various portions, one of skill in the art will appreciate that the overall lens shape includes a concave front face, a convex rear face, and the overall thickness of the annular ring portion  208   a ,  208   b ,  208   c  (excluding the central portion  206   a ,  206   b ,  206   c ) when seen in cross section is fairly uniform throughout each lens body  200   a ,  200   b ,  200   c . In various embodiments, the thickness may vary less than about 10%, such as 9%, 8%, 7%, 6%, 5%, 4%, 3%, 2%, 1% or even 0% over the entire width of annular portion  208   a ,  208   b ,  208   c . In specific, non-limiting embodiments, a suitable lens thickness for the annular ring portion of a small-diameter lens may be about 2 mm, and a suitable thickness for the annular ring portion of a large-diameter lens may be 2-3 cm, or even more. 
     Additionally, all of the lens bodies illustrated in  FIG. 2  lack the rear void or LED receiving well that flashlight lenses typically include. In fact, no portion of any of the lens bodies  200   a ,  200   b ,  200   c  is adapted to receive a LED light source or corresponding heat sink member within any portion of the lens body. 
     In various embodiments, central portion  206   a ,  206   b ,  206   c  may include a convex front surface  214   a ,  214   b ,  214   c , defining a forward-most point  218   a ,  218   b ,  218   c . In various embodiments, convex front surface  214   a ,  214   b ,  214   c  may incorporate any of various curvatures, and in some embodiments, the curvature may be substantially arcuate with a radius of no more than about 2-4 mm for a small-diameter flashlight having an overall lens diameter of less than about 1 cm, for example a lens having an overall diameter of about 6-8 mm. One of skill in the art will appreciate that this central portion diameter may be generally proportionately larger for larger diameter lenses. For example, a large diameter lens of 5-10 cm may have a central portion having a diameter of 1-4 cm, for example about 1.5-2.5 cm. The measurements described with reference to the embodiments of the lens are merely exemplary. Those of ordinary skill in the art will readily understand that other measurements may be used without deviating from the scope of the disclosure. 
     In various embodiments, annular ring portion  208   a ,  208   b ,  208   c  of lens body  200   a ,  200   b ,  200   c  may extend forward to front rim  220   a ,  220   b ,  220   c . In various embodiments, front rim  220   a ,  220   b ,  220   c  may extend farther forward than forward-most point  218   a ,  218   b ,  218   c  of central portion  206   a ,  206   b ,  206   c . In various embodiments, front rim  220   a ,  220   b ,  220   c  may include a chamfer between annular ring portion  208   a ,  208   b ,  208   c  and front rim  220   a ,  220   b ,  220   c  of at least about 0.2-0.5 mm of width for a small diameter flashlight. In some embodiments, the chamfer may have a width selected for a desired lens size and operational characteristics, and, as examples only, may be about 1.5 mm, about 2.0 mm, about 2.5 mm, or about 3.0 mm in width for a larger diameter lens. 
       FIGS. 3A and 3B  are cross-sectional views of a bi-convex lens ( FIG. 3A ) and a bi-concave lens ( FIG. 3B ), and both are examples of additional lens bodies that may form a part of an integrated bezel (front portion of a housing member) and lens system in accordance with various embodiments. In these embodiments, the lens  300   a ,  300   b  may be a simple bi-convex or bi-concave lens, with no additional central focusing elements. Although only the lenses  300   a ,  300   b  are illustrated in  FIGS. 3A and 3B , it will be understand that lenses  300   a ,  300   b  may form a part of a larger, unitary structure in some embodiments that may include, for example, a bezel (front portion) and optionally a body or housing member. 
       FIG. 4  is a cross-sectional view of a traditional lens  400  that may be used as a part of an integrated bezel (front portion of a housing member) and lens system in various embodiments. In various embodiments, this lens may have an overall thicker profile than some of the thin-profile lenses described for use herein. Although only the lens  400  is illustrated in  FIG. 4 , it will be understand that lens  400  may form a part of a larger, unitary structure in some embodiments that may include, for example, a bezel (front portion) and optionally a body or housing member. 
     As best seen in  FIGS. 5A and 5B , in various embodiments, adjustment of the LED position relative to the lens may provide a beam ranging between a wide beam or flood light (see, e.g.,  FIG. 5B ) and a narrow or spot beam (see, e.g.,  FIG. 5A ). In various embodiments, a spot beam may provide about +/−3° of angular distribution at about 50% of maximum intensity. An example of a wide beam is a distribution with an angular range of about +/−45° over which the intensity is at least about 50% of the maximum or on-axis value. In accordance with various embodiments, the light may be varied from spot beam to wide beam with the adjustment in position of the LED being no more than about 3-50 mm, depending on the lens diameter. A representation of the light rays LR calculated for an example of a lens and LED configuration is shown in each of  FIGS. 5A and 5B . As illustrated, in various embodiments, lens  500  may direct a substantial portion of light rays LR into the desired beam and a smaller portion of light rays LR may be expected to travel outside the desired beam. 
       FIGS. 6A-6D  are four cross-sectional views of an integrated bezel (front portion of a housing member) and lens system for a flashlight, showing a threaded adjustable bezel (front portion) with the light source in a wide beam or flood position ( FIG. 6A ) and a narrow or spot beam position ( FIG. 6B ), and a slidably-adjustable bezel (front portion) with the light source in a wide beam or flood position ( FIG. 6C ) and in a narrow or spot beam position ( FIG. 6D ), in accordance with various embodiments. As illustrated, in various embodiments, as shown in  FIGS. 6A and 6B , the integrated bezel (front portion) and lens system  600   a  may include a lens  640   a  and a bezel (front portion)  642   a  that may be continuous with one another, forming a single, integrated component. In some embodiments, bezel (front portion)  642   a  may be configured to couple to a body member  644   a , which may include a light source, such as LED  636 . In some embodiments, system  600   a  may also include an adjustment mechanism, such as a threaded coupling or engagement  646  between bezel (front portion)  642   a  and body member  644   a , which may permit adjustment of the spacing between the light source and the lens, thus enabling focusing of the resulting light beam as described in detail above. 
     In other embodiments, as shown in  FIGS. 6C and 6D , the integrated bezel (front portion of a housing member) and lens system  600   b  may include an integrated, one-piece lens  640   b  and bezel (front portion)  642   b  may be slidably mounted on body member  644   b . In some embodiments, the slidable mount may include one or more O-rings  648  that may facilitate adjustment of bezel (front portion)  642   b  on body member  644   b , which may permit adjustment of the spacing between LED  636  and lens  640   b , thus enabling focusing of the resulting light beam, for instance to produce a spot beam or a flood beam. Although threaded and slidable mounts are illustrated, one of skill in the art will appreciate that other suitable mechanism allowing a user to adjust the relative positions of the lens and light source may be used, for example those involving various slots and tabs, or any other mechanism that may allow for adjustment of the relative positions of lens and/or light source. 
     In various embodiments, integrated bezel (front portion of a housing member) and lens system  600   a ,  600   b  may be adjusted with the adjustment mechanism as described in order to provide a light beam with a wide beam having a distribution with an angular range of about +/−45° over which the intensity is at least 50% of the maximum or on-axis value. For that wide beam, integrated bezel (front portion) and lens system  600   a ,  600   b  may provide a substantially uniform intensity between at least about +/−10° of angular distribution. In various embodiments, system  600   a ,  600   b  also may provide an increased intensity for the spot beam as compared to a similar lens incorporating one or more flat or convex surfaces among its rear well sidewall, rear well base, front annular surface, and/or side surface. 
     In some embodiments, bezel (front portion)  642  may be provided with a grip-enhanced region, such as a region having grooves, ridges, swellings, textures, or the like, which may extend partially or completely around bezel (front portion)  642 . In various embodiments, the grip-enhanced region may aid a user, e.g., in a one-handed adjustment of the focus of the beam by providing a convenient grip for the thumb and forefinger on bezel (front portion)  642  while body member  644  is gripped by the other three fingers. In some embodiments, a control button may be provided on the flashlight body, e.g., at an end opposite bezel (front portion)  642 , or on bezel (front portion)  642  itself. 
     In various embodiments, body member  644  or other housing structures may be made from a metal such as aluminum or steel or a plastic such as ABS. Component materials may be selected to be compatible with lighting unit operation in harsh environments such as very high or very low ambient temperatures. 
       FIGS. 7A and 7B  show two cross-sectional views of fixed-focus flashlights configured for a wide beam ( FIG. 7A ) and a narrow or spot beam ( FIG. 7B ), each having a one-piece integrated lens system, bezel (front portion), and housing, in accordance with various embodiments. In the illustrated embodiments, system  700  includes a lens  740 , bezel (front portion)  742 , and body member  744  that are all one integrated, continuous piece, such a piece of injection-molded acrylic. Together, bezel  742  (front portion) and body member  744  form a continuous housing  746  for the flashlight. In the embodiment illustrated in  FIG. 7A , an LED  736  is disposed within the housing  746  in a position configured to produce a flood or wide beam. By contrast, in the embodiments illustrated in  FIG. 7B , an LED  736  is disposed within housing  746  in a position configured to produce a spot or narrow beam. Neither embodiment includes an adjustment mechanism; the LED is fixed in place. In various embodiments, electronics, batteries, and interconnections (not shown) may be provided in body member  744  of housing  746 . In some embodiments, an interior surface of housing  746  may include a threaded engagement for receiving a mount  748  for LED  736 . 
       FIGS. 8A and 8B  illustrate two views of an adjustable focus flashlight having a one-piece integrated optics system, bezel (front portion), and housing, including cross-sectional views of the flashlight with the light source in a wide beam or flood position ( FIG. 8A ) and with the light source in a narrow beam or spot beam position ( FIG. 8B ), in accordance with various embodiments. The embodiment illustrated in  FIG. 8  is similar to those illustrated in  FIG. 7 , except that the embodiment illustrated in  FIG. 8  includes an adjustment mechanism  850  for adjusting the position of LED  836  relative to lens  840 , thus changing the focus of the light beam between a wide beam or flood light ( FIG. 8A ) and a narrow beam or spot light ( FIG. 8B ) as described above in greater detail. In the illustrated embodiment, adjustment mechanism  850  includes a longitudinal slot  852 , thought which a tab or lever  854  may protrude. In use, a user may slide lever  854  forward in longitudinal slot  852 , towards bezel (front portion)  842  and lens  840 , thus decreasing the distance between LED  836  and lens  840 , and adjusting the light beam to a flood or wide beam. Conversely, the user may slide lever  854  back and away from bezel (front portion)  842  and lens  840  within longitudinal slot  852 , thus focusing the light beam to a narrow beam or spot light. 
     Although a lever and slot adjustment mechanism is illustrated, one of skill in the art will appreciate that any other adjustment mechanism may substituted that allows a user to adjust the distance between lens  840  and LED  836 . For example, although a longitudinal adjustment slot is illustrated in  FIG. 8 , one of skill in the art will appreciate that a slot that is slanted or diagonal with respect to the longitudinal axis of the flashlight may be substituted. For example, in one embodiment, the tab(s) that protrudes from a slanted slot(s) may rest inside a groove that is on the underside of a separate external ring around the flashlight body. In this embodiment, when the external ring is twisted relative to the body of the flashlight, the LED will move longitudinally relative to the optic. In another embodiment, the external ring may have one or more small tabs integrated therein, and those tabs may ride in slanted (e.g., diagonal) slots on the LED heatsink assembly inside the flashlight. 
     Although certain embodiments have been illustrated and described herein, it will be appreciated by those of ordinary skill in the art that a wide variety of alternate and/or equivalent embodiments or implementations calculated to achieve the same purposes may be substituted for the embodiments shown and described without departing from the scope. Those with skill in the art will readily appreciate that embodiments may be implemented in a very wide variety of ways. This application is intended to cover any adaptations or variations of the embodiments discussed herein. Therefore, it is manifestly intended that embodiments be limited only by the claims and the equivalents thereof.