Patent Document

This application is a continuation of non-provisional patent application Ser. No. 11/835,863, filed Aug. 8, 2007 now U.S. Pat. No. 7,755,461, which is a continuation of application Ser. No. 10/829,425, filed Apr. 22, 2004, now U.S. Pat. No. 7,256,671, issued Aug. 14, 2007. This application also claims priority to provisional application No. 60/464,734, filed Apr. 24, 2003. The above-identified applications are each incorporated herein by reference in their entirety. 
    
    
     BACKGROUND 
     1. Field of the Invention 
     The present invention relates generally to switches and, more particularly, to a light having a sealed switch interface. 
     2. Introduction 
     Current light switch designs for flashlights include toggle, rotary, slide or push button switches. In each of these designs, the manufacturer often tries to seal the switch from exposure to the elements. This exposure to the elements leads to corrosion of the contacts, which in turn leads to switch failure. To accomplish the task of sealing the switch, the manufacturer houses the switch inside of the light housing with the user interface protruding through the housing. For toggle and push button switches, a membrane is used to protect the switch. For switches that include a protruding knob or bezel, an o-ring is used to provide a seal. The slide switch provides no protection at all. The shortcomings of these designs include tearing of the membrane or abrasion of the o-ring, which results in a non-waterproof environment for the switch. Other shortcomings to these switch designs include small user interfaces, exclusive use of either right or left hand operation and switch stops that are easily damaged, corroded or clogged. 
     SUMMARY 
     A portable light system having a sealed switch, substantially as shown in and/or described in connection with at least one of the figures, as set forth more completely in the claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In order to describe the manner in which the above-recited and other advantages and features of the invention can be obtained, a more particular description of the invention briefly described above will be rendered by reference to specific embodiments thereof which are illustrated in the appended drawings. Understanding that these drawings depict only typical embodiments of the invention and are not therefore to be considered limiting of its scope, the invention will be described and explained with additional specificity and detail through the use of the accompanying drawings in which: 
         FIG. 1  illustrates an embodiment of a portable light; 
         FIG. 2  illustrates an exploded view of an embodiment of a portable light; 
         FIGS. 3A and 3B  illustrate the example operation of a switch activation element with switches contained in a housing; 
         FIGS. 4A and 4B  illustrate an example embodiment of a user interface element; 
         FIGS. 5A and 5B  illustrates an example embodiment of a housing; 
         FIGS. 6A ,  6 B, and  7  illustrate alternative embodiments of a positioning mechanism; 
         FIGS. 8A and 8B  illustrate an embodiment of a light controlling circuit; and 
         FIGS. 9 and 10  illustrate alternative uses of the switching mechanism of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     Various embodiments of the invention are discussed in detail below. While specific implementations are discussed, it should be understood that this is done for illustration purposes only. A person skilled in the relevant art will recognize that other components and configurations may be used without parting from the spirit and scope of the invention. 
     As noted, conventional light switch designs are deficient in their inability to shield the light switch from exposure to the elements. In accordance with the present invention, a light switch mechanism is provided that contains the light switch in a sealed housing, thereby ensuring that exposure of the housing to the elements will not affect the operation of the light switch itself. Control of the switch is effected through a switching interface element that remains external to the sealed housing during manipulation by the user. Puncturing of the sealed housing is therefore prevented. 
       FIG. 1  illustrates an embodiment of a portable sealed light that includes a light switch mechanism according to the present invention. As illustrated, portable sealed light  100  includes housing  102 , switching ring  104 , lens  108  and lens cap  106 . In one embodiment, housing  102  contains a light emitting diode (LED) array and a spot bulb. 
     Switching ring  104  is generally operative to control switching elements that reside in housing  102  without requiring a direct connection between a switch activating element in switching ring  104  and a switch element in the interior of housing  102 . In accordance with this feature of the present invention, housing  102  can then be environmentally sealed, thereby shielding the switching elements within housing  102  from corrosive and otherwise destructive effects in the environment of use. 
     As will be described in greater detail below, in one embodiment, the switching elements contained within housing  102  are magnetic switches that are activated by a magnet that is fixed in switching ring  104 . In this arrangement, movement of switching ring  104  into a position that brings the magnet within sufficient proximity of a magnetic switch serves to activate that magnetic switch. An operational mode of portable sealed light  100  can therefore be changed based on the activation of that switch. As would be appreciated, a plurality of switches can be included within housing  102  to thereby initiate a change to a plurality of operational modes. 
     Housing  102  can be sealed in a variety of ways. In one embodiment, lens  108  is affixed to housing  102  using an adhesive/sealant. Lens cap  106  would provide further support in assuring that lens  108  remains affixed to housing  102 . In another embodiment, the seal for housing  102  includes an o-ring that is compressed between housing  102  and the lens cap assembly. In general, since lens cap  106  is not part of the switching mechanism it is not rotated repeatedly. This would ensure that an o-ring would not receive excess wear and tear, which in turn maintains a waterproof housing. 
     User control of portable sealed light  100  is enabled through switching ring  104  that fits over a cylindrical portion of circular housing  102 . As noted, in one embodiment, switching ring  104  incorporates a magnet that is use to activate magnetic switches within housing  102 . This non-invasive switching mechanism ensures that housing  102  remains environmentally sealed. Significantly, the switching ring of the embodiment of  FIG. 1  can be designed to be large enough to operate with impaired hands (e.g., gloved, muddy or injured). Also, a circular switching ring configuration makes it easy to operate the user interface with either hand. 
     As further illustrated in  FIG. 1 , portable sealed light  100  includes mounting bracket  112  for affixing portable sealed light  110  to a headband, helmet, bicycle, etc. and power cord  110  that is used to power electronics contained within housing  102 . An embodiment of a electronic circuit that can be used to control the various operational modes using switching ring  104  is described in greater detail below with reference to  FIGS. 8A and 8B . 
     To further describe the structure of portable sealed light  100 , reference is now made to  FIG. 2 , which illustrates an exploded view of portable sealed light  100 . As illustrated, power cord  110  is coupled to housing  102  through cable grip  212  and cable grip nut  214 . Housing  102  also includes cylindrical portion  220  upon which switching ring  104  rests. Contained within housing  102  is circuit board assembly  230 . 
     In one embodiment, circuit board assembly  210  is comprised of circular PC board  232 , circular PC board  234 , and PC boards  236  and  238 . In addition to the inclusion of electronics and other conductors to couple circular PC board  232  to circular PC board  234 , PC boards  236  and  238  also provide a support function in maintaining the structural integrity of circuit board assembly  210 . 
     In one embodiment, circular PC board  232  includes magnetic switches that are positioned near the perimeter of circular PC board  232 . These magnetic switches are selectively activated when activation magnet  240  is moved radially around circular PC board  232  through the movement of switching ring  104 . When activation magnet  240  is brought into a close enough proximity to a magnetic switch that switch is then closed. Circular PC board  234 , on the other hand, includes sockets and other electronic connections that enable powering and support for LEDs  252 , parabolic reflector  254  and spot bulb  256 . 
     As would be appreciated, the particular design of circuit board assembly  210  would be dependent on the shape (e.g., cylindrical, rectangular, etc.) and overall size of housing  102 . Thus, the specific location and orientation of system components in circuit board assembly  210  would be implementation dependent. In general, it is envisioned that the switch elements in circuit board assembly  210  are located in positions that would enable discrete activation through the movement of a switch activation element in a user interface element that is configured to move relative to a surface of housing  102 . The features of the present invention are therefore not dependent on the specific shape of housing  102  or the user interface element that is designed to cooperate with housing  102 . 
     Finally, as further illustrated in  FIG. 2 , circuit board assembly  210  is secured in housing  102  using washer  260  and lens cap assembly  106 . As noted, it is a feature of the present invention that housing  102  can be environmentally sealed. Thus, the particular method by which circuit board assembly  210  is enclosed in housing  102  using lens cap assembly  106  would be implementation dependent. 
       FIGS. 3A and 3B  illustrate the example operation of a switch activation element with switches contained in a housing. As illustrated, housing  302  contains load circuits  342  and  344  that are selectively driven upon activation of magnetic switches  332  and  334 , respectively. Activation of magnetic switches  332  and  334  is based on the relative position of activation magnet  310  that is fixed in switching ring  304 . In one embodiment, magnetic reed switches  332  and  334  are positioned near the perimeter of a circular PC board, thereby enabling discrete activation upon the movement of a switch activation element in switching ring  304 . 
     As illustrated in  FIG. 3A , switching ring  304  has been rotated in such a manner that activation magnet  310  is positioned at a point near magnetic reed switch  332 . In the illustrated embodiment, this positioning is assisted through the use of positioning magnet  322 , which serves to temporarily fix the position of switching ring  304  relative to housing  302 . In this embodiment, positioning magnet  322  would not be sufficient on its own to activate magnetic reed switch  332 . Rather, only the strength of the magnetic field produced by activation magnet  310  when brought into proximity of positioning magnet  322 , and hence magnetic switch  332 , would be sufficient to activate magnetic switch  332 . In the illustrated position of  FIG. 3A , activation magnet  310  would be able to activate magnetic reed switch  322  and not magnetic switch  324 . 
       FIG. 3B  illustrates the effect of moving switching ring  304  to a new position such that activation magnet  310  is brought into proximity with positioning magnet  324 , and hence magnetic reed switch  334 . Again, it should be noted that positioning magnet  324  would not be sufficient on its own to activate magnetic switch  334 . When activation magnet  310  is brought into proximity to positioning magnet  324 , however, magnetic switch  332  would be deactivated while magnetic switch  334  would be activated. The end effect of this change in positioning of switching ring  304  is the driving of load circuit  344  instead of load circuit  342 . A different operational mode would therefore result. 
     In the embodiment of  FIGS. 3A and 3B , activation magnet  310  was used as part of the mechanism that positioned switching ring  304  relative to housing  302 . In an alternative embodiment, the mechanism for positioning switching ring  304  relative to housing  302  can be independent of activation magnet  310 . To illustrate an example of this alternative embodiment, reference is made to  FIGS. 4A and 4B , which illustrate a bottom and a side view, respectively, of an embodiment of a switching ring, and to  FIGS. 5A and 5B , which illustrate a top view and a side view of an embodiment of a housing. 
     As illustrated in the bottom view of  FIG. 4A , switching ring  400  includes activation magnet  410  and separate positioning magnets  420 . Activation magnet  410  is positioned in a particular cross section of switching ring  400  that would coincide with a plane of circular PC board  232 . This would enable activation magnet  410  to be brought into close proximity to the various magnetic switches that are located around the perimeter of circular PC board  232 . In this embodiment, the particular position of switching ring  400  at which activation magnet  410  would be positioned near a particular magnetic switch would be determined by the positioning of one of positioning magnets  420  in proximity to a counterpart positioning magnet located on the housing. 
       FIGS. 5A and 5B  illustrate a counterpart housing  500  that is designed to cooperate with switching ring  400 . When assembled, the bottom of switching ring  400 , illustrated in  FIG. 4A , would rest against end member  510  of housing  500 . Incorporated within end member  510  of housing  500  is positioning magnet  512 . As switching ring  400  is rotated around the cylindrical portion of housing  500 , positioning magnets  420  on switching ring  400  can be selectively engaged with positioning magnet  512  on housing  500 . This sequential engagement of positioning magnets  420  on switching ring  400  with positioning magnet  512  would therefore enable the user to control the position of activation magnet  410  relative to the magnetic switches contained in housing  500 . 
     As further illustrated in the embodiment of  FIGS. 4A ,  4 B, switching ring  400  also includes radial support guide  430 . In general, radial support guide  430  is designed to receive guide member  520  of housing  500  to thereby define a restricted range of movement of switching ring  400  relative to housing  500 . This restricted range of movement would encompass the range of movement needed to enable each of positioning magnets  420  on switching ring  400  to be engaged with positioning magnet  512  on housing  500 . 
     In one embodiment, positioning magnets  420  and  512  and activation magnet  410  can be encased in switching ring  400  and housing  500  to prevent the magnets from being damaged, corroded or clogged. 
     As thus described, the positioning mechanism can be independent of the activation element. In the example of  FIGS. 4A ,  4 B,  5 A, and  5 B, this positioning mechanism relied on multiple positioning magnets on switching ring  400  and a single positioning magnet on housing  500 . In an alternative embodiment, the positioning mechanism can be based on multiple positioning magnets on the housing and a single positioning magnet on the user interface element. 
       FIGS. 6A and 6B  illustrate an example of this embodiment. As illustrated, housing  610  includes positioning magnets  614  that are fixed in end member  612 . Positioning magnets  614  are radially distributed around the portion of end member  612  that is adjacent to the end surface of switching ring  620  when switching ring  620  becomes engaged with housing  610 . As illustrated in  FIG. 6A , positioning magnet  622  is located on the bottom end of switching ring  620  and is designed to move radially around the cylindrical portion of housing  610 . As further illustrated in  FIG. 6A , switching ring also includes activation magnet  624 . 
     In an alternative embodiment, the positioning magnets on housing  610  can also be moved from the end member  612  of housing  610  to the cylindrical portion of housing  610  around which switching ring  620  rotates.  FIG. 7  illustrates an example of this embodiment. As illustrated, housing  710  includes positioning magnets  712  that are located in cross-sectional plane  720 . Positional magnets  712  are designed to engage positional magnet  722  that is located in a corresponding cross-sectional plane  740  of switching ring  720 . As illustrated, switching ring  720  also includes activation magnet  724  that is located in cross-sectional plane  740  of switching ring  720 . As would be appreciated, positioning magnet  722  can also be located in the same cross-sectional plane as activation magnet  724 . This embodiment could be supported by a radial support guide such as that illustrated in  FIG. 4A  to thereby ensure that positional magnets  722  does not interact with magnetic switches contained within housing  710 . 
     While the various embodiments discussed above provide a particular method using magnets to effect positioning of a user interface element relative to the housing, this is not meant to be limiting. As would be appreciated, any mechanism can be used that would enable a user interface element to maintain a sufficiently stable position relative to the housing to thereby enable a non-invasive switch activation mechanism. For example, in an alternative embodiment, a ball and dedent system can be used in place of the positional magnets. 
     Regardless of the particular positioning mechanism used, a number of predefined positions of the switch activation element relative to the housing can be defined. These predefined positions would correspond to the switch activation element coming into proximity with the various switches contained in the housing. The positions of the switches within the housing also need to be fixed. This can be accomplished through the insertion of the circuit board assembly into the housing in a fixed orientation. In one embodiment, an alignment pin provides a guide by which the circuit board assembly can be inserted into the housing in the proper orientation to thereby ensure that the switches on the circuit board assembly are positioned to interact with the activation element when the user interface element is in one of the positions defined by the positioning mechanism. 
     An embodiment of a light controlling circuit within the housing is now described with reference to  FIGS. 8A and 8B . As illustrated in  FIG. 8A , the power for the circuit is supplied from DC source. The power is controlled to the circuit through a series of switches labeled S 1  thru S 5 . In one embodiment, switches S 1 -S 5  are magnetic reed switches. As will be described in greater detail below multiple switches can be used to control a single load, and multiple switches can be used to control multiple loads. 
     When the magnet housed in the switching ring is positioned at the first stop, switches S 1  and S 4  are activated. S 1  supplies power to the base of transistor Q 1  which turns the transistor on. With transistor Q 1  turned on, the electricity flows through transistor Q 1  to inductor L 1  and the DC-DC controller IC  1 . Capacitor C 1  provides input filtering of the supply power. Capacitor C 2  provides additional filtering of the input power that is used to supply IC  1 . IC  1  turns transistor Q 2  on and off at a particular frequency. In one embodiment, the maximum switching frequency of transistor Q 2  is 300 KHz. When Q 2  is turned on energy flows from the supply into inductor L 1  where the energy is stored. During this time V L1 =V IN . The load, isolated by schottkey diode D 1 , is supplied by the charge stored in capacitor C 4 . When Q 2  is turned off, the energy stored in inductor L 1  is added to the input voltage and I L  helps supply the load current and restores the energy discharged from capacitor C 4 . Capacitor C 4  supplies current to the load after inductor L 1  discharges. When transistor Q 2  turns off V L1 =V O −V IN . The operating frequency of transistor Q 2  is controlled by a feedback loop that samples the output voltage. With switch S 4  closed, the output voltage is sampled through a potentiometer P 1 . Potentiometer P 1  acts as a voltage divider. By adjusting potentiometer P 1 , the output voltage can be adjusted from input voltage to V out =V ref *(P 1   R2 /P 1   R1 +1), where P 1   R1  and P 1   R2  equal the resistance of P 1  and V ref  equals 1.5V. Capacitor C 3  is used to supply IC  1  with a reference voltage. 
     The current sense resistor R 1  sets the maximum output current, 
               R   1     =       0.00126   ⁢           ⁢   V   *     V   in           V   out     *     I   out               
where R 1  is equal to the current sense resistor, V in  is equal to the input voltage, V out  is equal to the output voltage and I out  is equal to the maximum output current.
 
     When the magnet is moved to switch position two, switch S 2  is closed while switches S 1 , S 3 , S 4  and S 5  are left open. The circuit operates the same as above, except the feedback circuit is disabled. With the feedback circuit disabled, IC  1  operates at the maximum frequency (e.g., 300 Khz). The output voltage is given by: 
               V   out     =       Eff   *     V   in     *     I   in         I   out             
where V out  equals the output voltage, Eff equals the efficiency of the circuit, V in  equals the input voltage, I in  equals the input current, and I out  equals the output current. The load on this circuit cannot exceed the efficiency of the circuit times the power input.
 
     When the magnet is moved to position three, switch S 5  is closed while switches S 1 , S 2 , S 3  and S 4  are open. Switch S 5  supplies voltage to the gate of transistor Q 3  from a voltage tap that is between LED  14  and LED  15 . With transistor Q 3  turned on power is supplied to the DC-DC controller IC  2  and inductor L 2 . Capacitor C 1  provides input filtering of the supply power. Capacitor C 5  provides additional filtering of the input power that is used to supply IC  2 . IC  2  turns transistor Q 4  on and off at a particular frequency. In one embodiment, the maximum switching frequency is 300 KHz. When transistor Q 4  is turned on energy flows from the supply into inductor L 2  where the energy is stored. During this time V L2 =V IN . The load, isolated by schottkey diodes D 3 , D 4  and D 5 , is supplied by the charge stored in capacitor C 7 . Schottkey diodes D 3 , D 4  and D 5  are used instead of a single high current diode due to the voltage drop associated with a single diode. When transistor Q 4  is turned off, the energy stored in inductor L 2  is added to the input voltage and I L2  helps supply the load current and restores the energy discharged from capacitor C 7 . Capacitor C 7  supplies current to the load after inductor L 2  discharges. When transistor Q 4  turns off V L2 =V O −V IN . The operating frequency is controlled by a feedback loop that samples the output voltage. The output voltage is sampled through a potentiometer P 2 . Potentiometer P 2  acts as a voltage divider. By adjusting potentiometer P 2 , the output voltage can be adjusted from input voltage to V out =V ref *(P 2   R2 /P 2   R1 +1), where P 2   R1  and P 2   R2  equal the resistance of P 2  and V ref  equals 1.5V. Capacitor C 6  is used to supply IC  2  with a reference voltage. 
     The current sense resistors R 2  and R 3  set the maximum output current, 
                 1     R   2       +     1     R   3         =       0.075   ⁢           ⁢   V   *     V   in           V   out     *     I   out               
where R 2  and R 3  are equal to the current sense resistors, V in  is equal to the input voltage, V out  is equal to the output voltage and I out  is equal to the maximum output current.
 
     The current sense resistor R 1  sets the maximum output current. When voltage is applied to the gate of transistor Q 3 , diode D 6  slowly drains capacitor C 4 . The size of capacitor C 4  determines the length of time that transistor Q 3  remains turned on. Also when switch S 5  is opened, diode D 6  drains the gate of transistor Q 3  to provide for a means of shutting transistor Q 3  off. 
     Initially, when voltage is applied to the gate of transistor Q 3 , the step-up converter does not boost the voltage above the supply voltage when the supply voltage of the battery is at or above the nominal open circuit voltage of the battery. By turning the switching ring to position  2  or  4  then back to position  3 , this allows the DC-DC step-up circuit to boost the output voltage to the preset voltage as determined by potentiometer P 2 . This scheme provides the means to allow for two output settings built into one circuit. 
     When the supply voltage is below the nominal open circuit voltage of the battery the circuit boosts the output voltage to 90% of the high setting of the boost circuit. 
     When the magnet is moved to position four, switches S 3  and S 5  are closed while switches S 1 , S 2 , and S 4  are open. This allows for both the LED and spot bulb circuit to operate simultaneously. The LED circuit operates with the feedback circuit disabled and the spot bulb circuit operates at the high setting. 
     In one embodiment, all of the components for the circuits are plugged into the PC board. This allows for customization of the circuit easily to accommodate for a variety of light outputs desired. The light output can be changed both in intensity, by adding additional LED&#39;s, or wavelength of emitted light, by changing LED types. The light can accommodate any wavelength LED from infrared to ultra violet. 
     In one embodiment, a color balanced LED array is used. For example, one color-balanced LED array can include yellow LEDs amongst a set of white LEDs to produce a color-balanced light output. This color balanced light output has been shown to produce better depth perception and clarity to a user. As would be appreciated, the value of a color balanced light output would be felt in any appropriate lighting application, whether or not a portable light was required. 
     In general, there are two problems that arise from the use of a LED array. First the power must be distributed evenly to each LED in the array. Conventional designs run parallel strings of LED&#39;s, which are in series. The problem with this scheme is that the LED&#39;s in the middle of the array tend to heat up and their resistance drops, thereby causing more current to flow through that particular LED string. Second, the LED wavelength type is fixed. This means that the user would have to custom order a particular LED combination or try and unsolder the LED&#39;s and replace them with the combination that suits their needs. Two problems arise from the user trying to replace the fixed LED&#39;s. First, the LED&#39;s need to be soldered, which can over heat and damage the LED. Second, the load must be balanced between the parallel LED strings. 
     Current light designs also try to add a spot bulb to overcome the LED&#39;s inability to project a concentrated beam of light any reasonable distance. Two solutions have been proposed to overcome this problem. First, the spot bulb is mounted to the side of the LED array. This causes the light pattern from the spot bulb to be offset from the LED array. Second, the LED&#39;s are embedded into the reflector of the spot bulb. This causes the light pattern from the spot bulb to be diffused. 
     In addition to the light-pattern problem, the spot bulb of conventional designs do not have any power management scheme. This means that the spot bulb runs directly from the input supply. Two problems arise from this scheme. First, the light output decreases as the battery voltage decreases. Second, the light output is limited to a maximum output due to the battery&#39;s fixed maximum voltage. 
     To solve some of the above problems circular PC board  234  has been provided that includes sockets that are wired in series around the circumference of a parabolic reflector  254  used for the spot bulb. With this arrangement, the user can easily change the LED&#39;s to suit the wavelength requirement. All that is needed to accomplish this task is to plug in the desired LED into the socket. There is no need to balance the load because the LED&#39;s are wired in series, thereby ensuring that there is equal current supplied to each LED. Additionally, the LED&#39;s light pattern is concentric with the spot bulb. Finally, since the LED&#39;s do not interfere with parabolic reflector  254 , the light pattern from the spot bulb is not compromised. 
     To solve the problem associated with a fixed maximum voltage supplying the spot bulb, the circuit of  FIGS. 8A and 8B  include a DC-DC switching power supply powering the spot bulb. This allows for the spot bulb to operate at the battery voltage and at a voltage above the supply voltage. The user can then select the voltage setting above the supply voltage. This allows for a custom light output for the spot bulb. 
     In one embodiment, as an alternative to a spot bulb, an additional LED array can be directly plugged into the spot bulb socket. The only adjustment that is needed is for the output voltage to be increased sufficiently to power the additional LED array. 
     To solve the problem of a fixed input to the switching power supply the inductor is plugged into a socket in the circuit board. By changing the inductor size, the user can select the voltage of the battery that will be used to operate the light. By selecting the input the user can then select the type of battery that will suit the users requirements. 
     In addition to the portable light uses described above, the non-invasive switch mechanism can also be applied in other contexts where a simple switch user interface is required or where the sealed nature of the switch is required. 
       FIG. 9  illustrates one example of an alternative use in the fluid or gas containment area. As illustrated, switching ring  910  can be coupled to a housing portion  920  that is exposed to a fluid or gas substance that must be contained. Housing portion  920  can be designed to house electronics or other measurement circuitry that, for example, can be designed to measure characteristics of the substance in pipe  930  or a rate of movement of the substance in pipe  930 . Using a switch mechanism of the present invention, control signals can be sent to electronics or other control apparatus within housing  920  without risking a breach of containment of pipe  930 . 
       FIG. 10  illustrates an alternative embodiment of an application within this area. As illustrated, switching ring can be designed to surround pipe  1020  to thereby control measurement apparatus within pipe  1020 . In one example, this measurement apparatus could be used to directly measure the flow of a liquid within pipe  1020 . 
     As would be appreciated, the principles of the present invention can be applied in a variety of contexts and in a variety of use situations. Indeed, the intended application will dictate the need to incorporate one or more of the features described above. For example, if the lighting system is not designed to be portable, a sealed housing may not be required. Rather, the simple user interface and color balanced LED feature may be sufficient for that application. 
     Although the above description may contain specific details, they should not be construed as limiting the claims in any way. Other configurations of the described embodiments of the invention are part of the scope of this invention. Accordingly, the appended claims and their legal equivalents only should define the invention, rather than any specific examples given.

Technology Category: f