Patent Publication Number: US-2015078015-A1

Title: Anti-theft collar for a light bulb

Description:
BACKGROUND 
     1. Field 
     The present disclosure relates generally to an anti-theft system for a light bulb, and more specifically to an anti-theft collar that prevents a light bulb from being removed from a light fixture. 
     2. Description of Related Art 
     Recently, a variety of alternatives to the incandescent bulb have emerged in the marketplace. For example, light-emitting diode (LED) bulbs and compact fluorescent bulbs have become increasingly available to meet an increasing demand for energy efficient alternatives to standard incandescent bulbs. LED bulbs have emerged as one energy-efficient, long-lasting alternative to incandescent light bulbs. One example of an LED bulb that can be used with standard light-bulb sockets is provided in U.S. Pub. No. US2013/0010480, which is incorporated by reference herein in its entirety. 
     An LED bulb may use less power, last longer, and cost less to operate as compared to incandescent alternatives. However, some LED bulbs may have a higher initial purchase price, and therefore require more of an initial investment. In addition to their functional advantages, LED bulbs may also be perceived as novel and aesthetically pleasing. Other types of (non-LED) bulbs may also cost more money and offer features not commonly available in traditional incandescent bulbs. Factors such as cost, durability, and visual appeal may lead to a greater risk of theft for some alternative light bulbs as compared to traditional incandescent light bulbs, which are relatively inexpensive and ubiquitous. The risk of theft may be particularly high for light bulbs that are installed in hotels, offices, or public areas that have minimal supervision. 
     Most traditional light-bulb fixtures are not designed to prevent theft of an installed light bulb. In fact, many traditional light-bulb fixtures include an Edison screw socket or bayonet mount that are designed for ease of light bulb installation and removal. Accordingly, there is a need for a device that can deter or prevent removal of a light bulb from the socket of a light fixture. 
     BRIEF SUMMARY 
     One exemplary embodiment is directed to an anti-theft system for preventing removal of a light bulb when installed in a socket housing of a light fixture. The anti-theft system includes a ring having a protrusion, wherein the ring is attached, or configured to be attached, to the light bulb. The anti-theft system also includes a collar configured to mechanically engage with the ring and the socket housing. The collar includes a wall portion that is configured to enclose at least a portion of the light bulb and at least a portion of the socket housing. The collar also includes a cavity portion that is formed within the wall portion. The cavity portion is configured to engage the protrusion of the light bulb to inhibit rotation of the light bulb with respect to the collar when the collar is installed. The collar also includes a lower portion that extends from one end of the wall portion. The lower portion has an upper surface that is configured to engage with an opposing lower surface of the socket housing to inhibit motion of the collar in a direction along a central axis of the light bulb. In some embodiments, the protrusion formed as part of the light bulb. 
     In some embodiments, an opening is formed in the wall portion. The opening is configured to at least partially encircle a key of the light fixture when the collar is installed to inhibit rotation of the collar with respect to the light fixture by mechanically engaging with the key. 
     In some embodiments, the cavity portion is formed from an opening in the wall portion of the collar. In other embodiments, the cavity portion is formed from a blind recess in the wall portion of the collar. For example, the cavity portion may not form a hole or opening in the wall portion of the collar. 
     In some embodiments, the collar is formed from two pieces that are configured to be mechanically joined by one or more mechanical interlocks. The two pieces may or may not be symmetric or identical to each other. In some embodiments, each mechanical interlock includes at least one tab portion on a first of the two pieces, and at least one slot portion on a second of the two pieces. The tab portion and the slot portion are configured to interlock with each other. In some cases, the tab portion includes a beveled leading edge to facilitate installation and the tab portion includes a catch barb to inhibit removal of the collar after installation. In some cases, the collar is formed from more than two pieces. 
     The light bulb may be an LED bulb. The light bulb may also be a non-LED bulb, including, for example, a compact florescent or incandescent light bulb. In some embodiments, the light bulb includes a base having a threaded portion for insertion into the socket housing. In this case, the protrusion is formed as part of a ring that is attached to the base of the light bulb above the threaded portion. In some cases, the ring is mechanically integrated with the base of the light bulb. In other cases, the ring is configured for installation on the base of the light bulb after the light bulb has been manufactured. 
     Another exemplary embodiment is directed to an anti-theft system for preventing removal of a light bulb when installed in a socket housing of a light fixture. The anti-theft system includes a ring having a protrusion, wherein the ring is attached to the light bulb. The anti-theft system also includes a collar configured to mechanically engage with the ring and the socket housing. The collar includes a wall portion that is configured to enclose a portion of the light bulb and a portion of the socket housing. The collar also includes a cavity portion formed within the wall portion. The cavity portion is configured to engage the protrusion of the light bulb to inhibit rotation of the light bulb with respect to the collar when the collar is installed. The collar also includes an opening formed in the wall portion. The opening is configured to at least partially encircle a key of the light fixture when the collar is installed to inhibit rotation of the collar with respect to the light fixture by mechanically engaging with the key. The cavity portion may be formed from an opening in the wall portion of the collar or may be formed from a blind recess in the wall portion. In some embodiments, the protrusion formed as part of the light bulb. 
    
    
     
       DESCRIPTION OF THE FIGURES 
         FIG. 1  depicts an exemplary anti-theft collar used to secure an LED bulb in a light fixture. 
         FIG. 2  depicts an exemplary LED light bulb having a ring and protrusions. 
         FIG. 3  depicts a cross-sectional view of an exemplary collar installed around an LED bulb having a ring with two protrusions. 
         FIG. 4  depicts one piece of an exemplary collar installed around a socket fixture and an LED bulb. 
         FIG. 5  depicts an exemplary anti-theft collar used to secure an LED bulb to a light fixture. 
         FIG. 6  depicts an exemplary LED light bulb having protrusions. 
         FIG. 7  depicts a cross-sectional view of an exemplary collar, an LED bulb, and a light fixture. 
         FIGS. 8A-B  depict two pieces of an exemplary collar. 
         FIG. 9A  depicts a top view of one piece of an exemplary collar. 
         FIG. 9B  depicts a top view of one piece of an exemplary collar. 
         FIG. 9C  depicts a top view of two pieces of an exemplary collar coupled by a mechanical interlock. 
     
    
    
     DETAILED DESCRIPTION 
     The following description is presented to enable a person of ordinary skill in the art to make and use the various embodiments. Descriptions of specific devices, techniques, and applications are provided only as examples. Various modifications to the examples described herein will be readily apparent to those of ordinary skill in the art, and the general principles defined herein may be applied to other examples and applications without departing from the spirit and scope of the various embodiments. Thus, the various embodiments are not intended to be limited to the examples described herein and shown, but are to be accorded the scope consistent with the claims. 
     The following description is provided with respect to an LED bulb. However, a person of ordinary skill in the art would understand that the examples can also be applied to other types of light bulbs that are not LED bulbs. For example, the anti-theft system and anti-theft collar described below can be used to secure a compact florescent, traditional incandescent, or other type of light bulb. 
     1. Anti-Theft System Including an Anti-Theft Collar 
       FIG. 1  depicts exemplary (anti-theft) collar  100  used to secure an LED bulb  200  to a light fixture  300 . In general, the collar  100  is configured to deter removal of the LED bulb  200  from the light fixture  300  by impeding relative motion between the LED bulb  200  and the light fixture  300 . In this example, the collar  100  is configured to mechanically engage with one or more features of the LED bulb  200  and a portion of a socket housing  310  of the light fixture  300  to prevent the rotation of the LED bulb  200  with respect to the socket housing  310 . 
     As shown in  FIG. 1 , the collar  100  includes a wall portion  102  that is configured to partially enclose the LED bulb  200  and the socket housing  310  of the light fixture  300 . In this example, the wall portion  102  encircles a portion of the base  210  of the LED bulb  200  and a portion of the socket housing  310 . As shown in  FIG. 1 , the wall portion  102  is formed from two semi-cylindrical-shaped pieces that are joined by a mechanical interlock  112 . 
     As shown in  FIG. 1 , the collar  100  includes a cavity portion  104  within the wall portion  102 . In general, the cavity portion  104  includes a recessed feature that forms a recessed depression or hole in the wall portion  102  of the collar  100 . In this example, the cavity portion  104  extends completely through the wall portion  102  forming a hole in the wall portion  102 . The cavity portion  104  is configured to mechanically engage a protrusion  204  that is attached to or otherwise fixed with respect to the bulb  200 . In this example, the protrusion  204  extends into the cavity portion  104  and through the wall section  102 , preventing the rotation of the bulb  200  with respect to the collar  100 . 
     The collar  100  also includes an opening  106  formed in the wall portion  102 . In general, the opening  106  includes a void or hole in the wall portion  102  of the collar  100 . As shown in  FIG. 1 , a key  312  of the light fixture  300  protrudes through the opening  106  when the collar  100  is installed. In this example, the key  312  is a turn knob that is used to control the power and/or power level supplied to the LED bulb  200 . In other examples, the key  312  may include a push/pull-type switch for controlling the power to the LED bulb  200 . The opening  106  in the wall portion  102  serves two purposes. First, the opening  106  permits external access to the key  312 . Second, the opening  106  is configured to mechanically engage with the key  312  to prevent rotation of the collar  100  with respect to the socket housing  310  of the lighting fixture  300 . 
     In this example, the opening  106  is configured to encircle the key  312  when the collar  100  is installed on the light fixture  300 . The opening  106  is substantially oval-shaped and is at least as large as the largest portion of the key  312 , which facilitates installation of the collar  100  without having to remove the key  312  or deform the collar  100 . However, in other embodiments, the opening  106  may only partially encircle the key  312  and have a size that is slightly larger than a shaft portion of the key  312 . For example, the opening  106  may be formed from a u-shaped channel in the wall portion  102  of the collar  100  that is configured to slide around the key  312  during installation. The size, shape, and location of the opening  106  may vary depending on the configuration of key  312  and socket housing  310 . 
     In some embodiments, the collar  100  may not have a lower opening, if, for example, the collar is used on a light fixture that does not have a key  312 . In this case, the key cannot be used to prevent the collar  100  from rotating with respect to the light fixture  300 . However, for cases where the light fixture does not include a key  312 , the collar  100  may include one or more additional features that prevent the LED bulb  200  from being removed from the light fixture  300 . 
     For example, as shown in  FIG. 1 , the collar  100  also includes a lower portion  108  extending from one end of the wall portion  102 . The lower portion  108  is configured to prevent the LED bulb  200  and collar  100  from being removed from the lighting fixture  300 . Specifically, the lower portion  108  prevents the collar  100  and the LED bulb  200  from being pulled completely out of the socket housing  310 . In this example, the lower portion  108  is formed from a portion of both pieces of the collar  100  that extend from the bottom edge of the wall portion  102  to form an inverted dome-shaped structure. The lower portion  108  is configured to curve around the bottom of the socket housing  310  of the light fixture  300  when installed. In this example, the lower portion  108  also forms a hole or opening for the passage of wires and/or the post used to connect the socket housing  310  with other parts of the lamp or appliance. In this example, the wall portion  102  and lower portion  108  together completely enclose the socket housing  310 . In an alternative embodiment, the lower portion may be formed from another shape. For example, the lower portion may extend from one end of the wall portion at a 90 degree angle from the wall portion to form a flat-bottomed lower portion. The lower portion may also be formed from one or more finger-like protrusions configured to inhibit motion of the collar  100  along the central axis  250  of the LED bulb  200 . 
     In the example depicted in  FIGS. 1 and 4 , the lower portion  108  is configured to engage with the socket housing to inhibit motion of the collar  100  with respect to the socket housing  310  in a direction along a central axis  250  of the LED bulb. This prevents the collar  100  and LED bulb  200  (which are mechanically engaged by the protrusion  204  and cavity  104 ) from being removed from the lighting fixture  300  by unscrewing the LED bulb  200 . A more detailed description of the lower portion  108  is provided below with respect to  FIG. 4 . 
     As discussed in more detail with respect to  FIGS. 10A-B  and  11 A-C, collar  100  is formed from two pieces that are configured to be mechanically joined during installation. As shown in  FIG. 1 , collar  100  includes multiple mechanical interlocks  112  that join the two pieces together when installed on the lighting fixture. In this example, the mechanical interlocks  112  are also configured to inhibit disassembly and removal from the LED bulb  200  and light fixture  300  to deter theft of the LED bulb  200 . Specifically, the mechanical interlocks  112  include a tapered catch-barb tab portion that facilitates installation and inhibits removal without a specialized tool. 
       FIG. 2  depicts an exemplary LED bulb  200  having a ring  206  with two protrusions  204 . As described above with respect to  FIG. 1 , each protrusion  204  is configured to engage with a corresponding cavity portion  104  of the collar  100  to prevent rotation of the LED bulb  200  with respect to the collar  100 . Each protrusion  204  may also engage with the cavity portion to also prevent relative motion between the collar  100  and the LED bulb  200  in a direction along a central axis  250  of the LED bulb  200 . In some cases, the protrusions  204  may also be referred to as protuberances or nubs. 
     In this example, each protrusion  204  is formed from a rectangular protrusion extending outward radially from the base  210  of the LED bulb  200 . As shown in  FIG. 2 , the protrusions  204  are formed as part of a ring  206  that is attached to the base  210  of the LED bulb  200 . In this case, the ring  206  mechanically engages with one or more cooling fins  221  to prevent rotation of the ring  206  with respect to the base  210  of the LED bulb  200 . The ring  206  may also be bonded to the base  210  using an adhesive or other mechanical bonding technique. In some embodiments, only one protrusion  204  may be formed as part of the ring  206 . Alternatively, there may be more than two protrusions  204  formed as part of the ring  206 . 
     In this example, the ring  206  having protrusions  204  may be installed on the base  210  during the manufacturing process. The ring  206  may also be installed after manufacture by a purchaser or end-user of the LED bulb  200 . A customer-installed alternative may be advantageous by allowing the manufacture to produce one type of LED bulb that can be used for locking and non-locking applications. In this case, the ring  206  can be installed on the LED bulb  200  by the purchaser, end-user, or other person, and convert a non-locking LED bulb to a locking LED bulb, as needed. 
     In alternative examples that do not include and LED bulb or do not include an LED bulb having cooling fins, the ring  206  may be attached to the base using another feature of the light bulb. For example, the ring may mechanically engage with ridge or groove in the base of the light bulb to prevent the rotation of the ring with respect to the light bulb. In some cases, there is no feature to prevent the rotation of the ring with respect to the light bulb and the ring is attached to the light bulb by an adhesive or other bonding technique. 
       FIG. 3  depicts a cross-sectional view of a collar  100  used to secure an LED bulb  200  with protrusions  204  to a socket housing  310  of a lighting fixture. As shown in  FIG. 3 , the protrusions  204  are formed as part of ring  206 , which is attached to the base  210  of the LED bulb  200 . The ring  206  includes multiple grooves that are configured to mechanically engage with the fins  221  of the base  210 . The mechanical engagement of the grooves in the ring  206  and the fins  221  of the base  210  prevent the ring  206  from rotating with respect to the LED bulb  200 . As mentioned above, in applications where a finned LED bulb is not used, the light bulb may include other features to mechanically engage the ring. In some cases, there is no feature to mechanically engage the ring to prevent rotation and the ring is attached to the light bulb by an adhesive or other bonding technique. 
     As shown in  FIG. 3 , the protrusions  204  are formed from two rectangular protrusions that extend radially from the central axis  250  of the LED bulb and mechanically engage corresponding cavity portions  204  formed in the wall portion  102  of the collar  100 . In this example, the protrusions  204  extend completely through the wall portion  102 . The mechanical engagement between the protrusions  204  and the cavity portions  204  prevents the LED bulb  200  from rotating with respect to the collar  100 . 
     As shown in  FIG. 3 , the wall portion  102  of the collar  100  is larger than the socket housing  310  to provide a gap between the socket housing  310  and the collar  100  when installed. Typically, the gap is sufficiently large to allow for minor variations in the size and shape of the socket housing  310  to avoid a mechanical interference between the collar  100  and the socket housing  310 . The gap is also smaller than the overlap between the protrusion  204  and the cavity portion  104  in a direction perpendicular to the central axis  250  of the LED bulb  200  to ensure that the protrusion  204  and cavity portion  104  remain mechanically engaged. 
       FIG. 4  depicts one piece of an exemplary collar installed around a socket fixture  310  and LED bulb  200 . The view shown in  FIG. 4  is at approximately 90 degrees with respect to the cross-section view depicted in  FIG. 3 . As shown in  FIG. 4 , the collar  100  includes a lower portion  108  that extends from one end of the wall portion  102  to form an inverted dome-shaped structure that encloses the lower portion of the socket housing  310 . The lower portion  108  includes an upper surface  111  that is configured to engage with an opposing lower surface  311  of the socket housing  310  to inhibit motion of the collar in a direction along a central axis of the LED bulb  250 . The engagement between the upper surface  111  of the lower portion  108  and the opposing lower surface  311  of the socket housing  310  prevents the LED bulb  200  and the collar  100  from being removed from the lighting fixture. In this example, the LED bulb  200  is prevented from becoming completely unscrewed from the socket housing  310  because the upper surface  111  of the lower portion  108  comes in contact with the lower surface  311  of the socket housing  310  preventing the removal of the LED bulb  200  from the socket housing  310 . 
     As shown in  FIG. 4 , the lower portion  108  also forms a hole or opening to allow the socket housing  310  to be attached to the rest of the lighting fixture. The hole or opening also allows for wires or other electrical connections to be routed to the socket housing  310 . 
     In an alternative embodiment, the lower portion may not be a fully revolved dome-shaped structure. For example, the lower portion may be formed from two or more finger-shaped structures that extend from the bottom end of the wall structure  102  towards the central axis  250 . In this case, each finger-shaped structure includes an upper surface that is configured to engage with the lower surface of the socket housing to inhibit motion of the collar in a direction along the central axis  250 . 
       FIG. 5  depicts another exemplary (anti-theft) collar  500  used to secure an LED bulb  600  to a light fixture  300 . Similar to the collar  100  of  FIG. 1 , the collar  500  of  FIG. 5  is configured to mechanically engage with one or more features of the LED bulb  600  and a portion of a socket housing  310  of the light fixture  300  to prevent the rotation of the LED bulb  600  within the socket housing  310 . 
     As shown in  FIG. 5 , the collar  500  includes a wall portion  502  that is configured to partially enclose the LED bulb  600  and the socket housing  310  of the light fixture  300 . In this example, the wall portion  502  is formed from two semi-cylindrical-shaped pieces that are joined by multiple mechanical interlocks  512 . 
     As shown in  FIGS. 5 and 7 , the collar  500  also includes a cavity portion  504  within the wall portion  502 . In this example, the cavity portion  504  forms a blind recessed pocket in the wall portion  502 . Unlike the collar  100  discussed above, the cavity portion  504  does not extend completely through the wall portion  502  to form a hole. The cavity portion  504  is configured to mechanically engage a protrusion  604  that is attached to or otherwise fixed with respect to the bulb  600 . The protrusion  604  extends into the cavity portion  504  preventing the rotation of the bulb  600  with respect to the collar  500 . 
     As shown in  FIG. 5 , the collar  500  includes an opening  506  formed in the wall portion  502 . The key  312  of the lighting fixture  300  protrudes through the opening  506  when the collar  500  is installed. As previously described, the opening  506  permits external access to the key  312  and is also configured to mechanically engage with the key to prevent rotation of the collar  500  with respect to the light fixture  300 . 
     In some embodiments, the collar  500  may not have a lower portion, if, for example, the collar is used on a light fixture that does not have a key. In this case, the LED bulb  600  and collar  500  may have one or more additional features that prevent the LED bulb  600  from being removed from the light fixture  300 . 
     For example, as shown in  FIGS. 5 and 7 , the collar  500  also includes a lower portion  508  extending from one end of the wall portion  502 . The lower portion  508  may prevent the LED bulb  600  and collar  600  from being removed from the lighting fixture  300 . The lower portion  508  is structurally and functionally similar to the lower portion  108  of collar  100  discussed above with respect to  FIGS. 1 and 4 . 
       FIG. 6  depicts an exemplary LED bulb  600  that may be used with collar  500 . LED bulb  600  includes two protrusions  604  that are formed as part of a ring  602 . In this example, the protrusions  604  on LED bulb  600  are beveled at the outer edge to improve mechanical engagement with the recessed portion  504  of the collar  500 . In particular, because the collar  500  is tapered near cavity portions  504 , the beveled protrusions  604  maximize the engagement with the cavity portion  504  of the collar  500  by extending into the cavity portion  504  deeper than possible if the protrusions were square in profile shape. 
       FIG. 7  depicts a cross-sectional view of the collar  500  used to secure an LED bulb  600  with protrusions  604  to a socket housing  310  of a lighting fixture. As shown in  FIG. 6 , the protrusions  604  are formed as part of ring  602 , which is integrated into the base  610  of the LED bulb  200 . In this example, the ring  602  is configured to be integrated into the base  610  as part of the manufacturing process. In an alternative embodiment, the ring  602  could be configured for installation after manufacturing the LED bulb  600 , by a purchaser or end-user of the LED bulb  600 . In some embodiments, the ring  602  includes multiple grooves that are configured to mechanically engage with the fins of the base to prevent the ring  602  from rotating with respect to the LED bulb  600 . 
     As shown in  FIG. 7 , the protrusions  604  extend radially from the central axis  650  of the LED bulb  600  and mechanically engage corresponding cavity portions  504  formed in the wall portion  502  of the collar  500 . In this example, the protrusions  604  do not extend completely through the wall portion  502 . The mechanical engagement between the protrusions  604  and the cavity portions  504  prevents the LED bulb  600  from rotating with respect to the collar  500 . The collar  500  also includes a lower portion  508  configured to engage with the socket housing  310  to prevent the collar  500  and LED bulb  600  from being removed from the lighting fixture. The engagement between the lower porting  508  and the socket housing  310  is similar to that described above with respect to collar  100 . 
     2. Anti-Theft Collar Installation and Removal 
     As previously mentioned, exemplary collars  100  and  500  are formed from two pieces for installation and removal. To install a two-piece collar, each piece of the collar is typically placed on either side of the base of a light bulb installed within a light fixture. The pieces of the collar are aligned with protrusions or nubs on the light bulb so that corresponding features on the collar (cavity portions or ribs) mechanically engage with the light bulb. Additionally, the pieces of the collar are aligned so that the opening in the wall portion of the collar aligns with a key on the light fixture. If the light fixture includes a key, the key protrudes through the opening when the collar is installed. 
     The two pieces of the collar are then pressed together around the base of the light bulb and the light fixture to abut the edges of the two pieces of the collar and engage the mechanical interlocks (described in more detail below with respect to  FIGS. 8A-B  and  9 A-C). When installed in this manner, the collar encloses at least a portion of a socket housing of the light fixture and at least a portion of the base of the light bulb. The pieces of the collar may be symmetric or have identical geometry. In some cases, the pieces of the collar are not symmetric. Non-symmetric or non-identical geometry may further inhibit the removal of the collar by preventing disengagement of the mechanical interlocks by shifting of the pieces with respect to each other. 
       FIGS. 8A-B  depict two pieces of exemplary collar  800   a  and  800   b  having a mechanical interlock for joining the pieces. The following example is provided with respect to collar pieces  800   a  and  800   b  that can be joined to form a collar  800 . However, the mechanical interlocks may be substantially similar for the other collar embodiments  100  and  500 , discussed above. 
     In this example, each piece of the collar  800  includes two tabs  820  and two slots  818 . The tabs  820  on one piece of the collar ( 800   a  or  800   b ) slide into corresponding slots  818  on the other mating piece of the collar ( 800   b  or  800   a ) to join and lock the pieces together to form the collar  800 . The tabs  820  are configured such that they are easy to insert but difficult to disengage once inserted, thus serving as a theft deterrent. In this example, the tabs  820  include a beveled leading edge to facilitate insertion into a corresponding slot  818 . The tabs  820  also include a catch barb that engages with the slot  818  when installed to prevent disassembly of the two pieces. 
     As an additional deterrent, in this example, separation of the two pieces of the collar requires disengagement of multiple tabs  820  at the same time. Simultaneous disengagement may be made more difficult if the two pieces do not have interlocks having exactly the same geometry. For example, the tabs may be slightly offset to prevent the two pieces from being disassembled by merely shifting the pieces. 
       FIGS. 9A-B  depict top views of two pieces of an anti-theft collar ( 800   a  and  800   b ) when the pieces are separated.  FIG. 9C  depicts a top view of the pieces ( 800   a  and  800   b ) when they are interlocked by sliding the tabs  820  into the slots  818  for form the complete collar  800 . Other types of mechanical interlocks may be used to join the pieces of the collar  800 . These may include, for example, a variety of fasteners, clasps, threaded connectors, or adhesives. In some embodiments, the mechanical interlock may comprise a flexible or inflexible band that encloses the collar. In some embodiments, the mechanical interlock may not be removable. 
     As discussed above, exemplary collars  100 ,  500 , and  800  are designed to comprise two pieces to enable installation and removal. However, other collar designs that enable installation and removal are also possible. For example, a collar may comprise more than two pieces that can be locked together and detached from each other. The pieces of the collar may also hinge at one or more joints to enable them to pivot with respect to each other rather than detaching from each other completely. One or more pieces may also be connected to each other by a material or joint that provides for expansion between the sections, such as a flexible mesh or elastic. 
     The anti-theft collar may be fabricated from a variety of materials. These may include, for example, various forms of polycarbonates, metals, woods, or other materials that provide suitable strength and rigidity to prevent cracking or breaking of the collar by hand. The anti-theft collar may be fabricated using an injection molding, a machining, or another fabrication technique. The anti-theft collar may be fabricated from one type of material, or the collar may be fabricated from multiple materials. For example, the mechanical interlocks may be fabricated from a different material than the walls of the collar, and attached to the collar using an adhesive, fastener, or other bonding technique. 
     The examples above are intended to be illustrative rather than comprehensive. A person having skill in the art will recognize that there are many possible collar designs and materials that will achieve the desired result of preventing removal of a light bulb from a light fixture.