Abstract:
In one aspect, the invention is directed to a treatment light comprising a support member having at least two light source support portions: each support portion adapted to be operatively connected a light source; each light source comprising one or more LEDs, particularly a plurality of LEDs associated with a focusing material which focuses the LED emitted lights into cones, the at least two light sources adapted to be fixed at spaced apart positions proximate to either side of the head of a user, the support members defining a space for positioning the head of the user next to and potentially in between the at least two light sources. Preferably, the potential contact surfaces have a steady state temperature of no greater than 120 degrees Fahrenheit when tested at an ambient temperature of 72 degrees Fahrenheit. According to one embodiment of the invention, the potential contact surfaces are no hotter than 100 degrees Fahrenheit despite generating a cumulative output of 60 to 65 watts of power.

Description:
FIELD OF THE INVENTION 
       [0001]    The invention relates to a task light and more particularly to an operating room light that incorporates LEDs. 
       BACKGROUND OF THE INVENTION 
       [0002]    Surgical treatment lights employed in rapidly deployable temporary field hospitals typically comprise a single incandescent or halogen light source. These medical treatment tights are typically required to withstand hot ambient temperatures of up to 130 degrees Fahrenheit and other harsh conditions. Preferred design criteria for such lights include light weight, simple operation, reduced heat emission to avoid drying living tissue or burning the user, sterile replaceable handling levers, longevity particularly reduced need for spare parts including replacement bulbs and rapid assembly and deployment into a compact easily supportable structure from a portable kit. 
         [0003]    Typical non-portable operating room lighting comprises large multiple strong light sources which have heavy structural support systems that make them capable of adjustable positioning to avoid and fill shadows and are typically capable of wide lateral positioning to minimize shadowing attributable to the surgeons head. This type of heavy structure is impractical in rapidly deployable temporary field hospitals which provide first line care in a Forward Resuscitative Surgery System (FRSS) described herein. 
       SUMMARY OF THE INVENTION 
       [0004]    In one aspect, the invention is directed to a treatment light that is adapted for portable use by way of its relatively low weight and/or relatively small size, and wherein the light incorporates LEDs into multiple light sources which are spaced from each other. 
         [0005]    In another aspect, the invention is directed to a treatment light that is adapted for portable use by way of its relatively low weight and/or relatively small size, and wherein the light incorporates at least two light sources which are separated by a space which can accommodate a user&#39;s head and which remains at a temperature which is less than 130 degrees Fahrenheit under steady state conditions with ambient temperature at 72 degrees Fahrenheit. 
         [0006]    In another aspect, the invention is directed to a light with a handle mount that is changeable so that the light can accommodate a plurality of handles which have different mounting means (eg. one handle may have a particular type of thread, while another may have a different type of thread or may have a non-thread type of mounting means, such as, for example, a bayonet fitting [is this shown in the drawing?]. 
         [0007]    In another aspect, the invention is directed to a portable treatment light kit comprising a support structure having at least two light source support portions, each support portion adapted to be connected to a light source comprising a plurality of LEDs; at least two light sources each comprising a plurality of LEDs; the at least two of the light sources adapted to be readily adjusted to a position which defines at least one space between them for placement of a user&#39;s head in substantial lateral alignment therebetween when in use; each light source operatively associated with a heat elimination system capable of drawing heat away from potential contact surfaces with the user&#39;s head when positioned in the space. 
         [0008]    In another aspect, the invention is directed to a portable treatment light that has a support structure having at least two (and in some embodiments three or more), support portions (points of attachment for light sources to be described) that are spaced apart (and in some embodiments extending or radiating from a junction in spaced apart fashion), each support portion being operatively attached to a light source having a plurality of LEDs, the light sources capable of being fixedly positioned or already pre-positioned (in virtue the spatial arrangement of the support portions to which they are attached) to define at least one space between them for placement of a user&#39;s head in lateral alignment (though not necessarily in vertical alignment) between them, when in use, each light source operatively associated with a heat transfer system for drawing heat away from the points of potential contact with the user&#39;s head when positioned in the space. By being positioned in proximity to the user&#39;s head, in approximate lateral alignment with the middle of the space and in relative close proximity to the user&#39;s head (also more closely aligned in a vertical position relative to the placement in a typical permanent operating room), the support structure itself provides a reference point to position the LED light sources so that shadowing is well reduced and the available output is well used. Using the light in this fashion is made possible by a heat reduction system that prevents burning to the touch. Importantly this combination of features has been found to be compatible with a portable lighting system, that employs LED lights which are generally longer-lasting than conventional incandescent bulbs, and is compact, rapidly assembled, easily used and rapidly adjusted. 
         [0009]    Accordingly, in one embodiment, the invention is directed to a support structure that defines a position for the light sources relative to the head that is both adapted to avoid shadowing while also according well with a selected light focusing material and a selected distance at which the light is most needed. Optionally, this distance being somewhat longer that the distance between the user&#39;s eyes and the task surface, is within 30 to 48 inch range, optionally within the 33 to 45 inch distance range, optionally within the 36 to 42 inch range, optionally approximately one meter. The handle is optionally closely available at the center of the light sources to reposition the light to easily maintain the positioning demarcated by the positioning of the light next to the head and that accords with the heat reduction capability and the characteristics of the LED light focusing material and the watt output of the LEDs. The portable treatment light is optionally used with a flexible arm that is designed to support 15 pounds and optionally the light is therefore less than 15 pounds, optionally less than 10 pounds, optionally less than 5 pounds, optionally less than 3 pounds. The heat reduction capability is optionally selected to accord with a contact surface temperature of optionally less than 124 degrees Fahrenheit, optionally less than 120 degrees Fahrenheit, optionally less than 110 degrees Fahrenheit, optionally no greater than 100 degrees Fahrenheit. Accordingly, in a general aspect the portable treatment light of the invention has spaced LED light sources that demarcate a space for the user&#39;s head that accords with pre-selected heat dissipating and focal distance characteristics. 
         [0010]    Accordingly, in one embodiment, the invention is directed to a portable treatment light comprising: 
         [0011]    at least three support members radiating from a hub; 
         [0012]    each support member supporting a light source positioned distally from the hub comprising a plurality of LED units; 
         [0013]    each of the three support members defining at least one space between it and a respective adjacent support member for placement of a user&#39;s head between two light sources supported by two adjacent support members, when in use; 
         [0014]    each light source operatively associated to a heat dissipater for drawing heat away from the user&#39;s head when the user&#39;s head is positioned in the space. 
         [0015]    In another aspect, the invention is directed to a vast improvement in compact portable surgical light technology by employing long-lasting light emitting diodes as a light source. 
         [0016]    Accordingly, in one aspect, the invention is directed to a treatment light comprising a support member having at least two light source support portions; each support portion adapted to be operatively connected a light source; each light source comprising one or more LEDs, particularly a plurality of LEDs associated with a focusing material which focuses the LED emitted lights into cones, the at least two light sources adapted to be fixed at spaced apart positions proximate to either side of the head of a user, the support members defining a space for positioning the head of the user next to and potentially in between the at least two light sources, and wherein those positions focus the respective beams of light generated by the light sources on a task surface at a distance typical of the distance between the user&#39;s head and the treatment area (approximately one meter for surgical applications in field hospitals) each light source operatively associated with a heat dissipation system capable of drawing heat away from potential contact surfaces with the head of the user when positioned in the space next to the user. Preferably, the potential contact surfaces have a steady state temperature of no greater than 120 degrees Fahrenheit when tested at an ambient temperature of 72 degrees Fahrenheit. According to one embodiment of the invention, the potential contact surfaces are no hotter than 100 degrees Fahrenheit despite generating a cumulative output of 60 to 65 watts of power. We have also found that a support member that fixes the positions of the at least two and optionally three LED-based light sources into a compact spherical area (obviating the need for a weight-adding variable positioning structure for adjusting the positions of light sources relative to one another) is able to eliminate shadows in a fashion akin to more powerful widely spaced and distantly positioned light sources without diminishing necessary illumination or generating contact surfaces that could burn the user or adversely affects the patient tissues. Accordingly we have found that focused LED light technology (including attendant advantages of the light colour variations that enhance this technology (combinations of 3500 and 5500 degree Kelvin diodes)) can be employed outside optimal permanent hospital settings (air conditioned, roomy, spacious, weight supporting, power abundant) and is compatible with the daunting rigorous demands of rapidly deployable field hospitals and other settings with comparable power, space, ambient temperature, weight supporting or portability constraints. Weight and size constraints may vary and may be set so that the task light (with support arm and base) not weigh more than 8.2 Kg (18 lbs) without its shipping case or optionally not weigh more than 16 Kg (35 lbs) in its shipping case or that the task light fit into a packing case 1220×432×87 mm (48″×17″×7″) or that any combination of these requirement be applicable. Optionally, the support arm of the task light has a range of adjustability that may include 1 m height adjustment, and/or 0.75 m radial adjustment and/or 30 degrees head angle adjustment. 
         [0017]    Other aspects and features of the present invention will become apparent, to those ordinarily skilled in the art, upon review of the following description of the specific embodiments of the invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0018]    For a better understanding of the present invention, and to show more clearly how it may be carried into effect, reference will now be made, by way of example, to the accompanying drawings, which illustrate aspects of embodiments of the present invention and in which: 
           [0019]      FIG. 1  is a perspective view of a task light and a user in accordance with an embodiment of the invention; 
           [0020]      FIG. 2  is a perspective view of the task light shown in  FIG. 1 , shown from underneath and with some components removed for clarity; 
           [0021]      FIG. 3  is a magnified exploded perspective view of some of the elements of the task light shown in  FIG. 1 ; 
           [0022]      FIG. 3   a  is a magnified exploded perspective view of a heat dissipation device from the task light shown in  FIG. 1 ; 
           [0023]      FIG. 4  is a sectional perspective view of the task light is shown in  FIG. 1 ; 
           [0024]      FIG. 5  is a top plan view of the task light shown in  FIG. 1 , illustrating a possible positioning of the head of a user; and 
           [0025]      FIG. 6  is a plan view of a task light in accordance with another embodiment of the invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0026]    Reference is made to  FIG. 1 , which shows a task light  10  according to an embodiment of the present invention. The task light  10  may be used for any suitable task, such as, for example, performing a medical or dental procedure on a human patient or on an animal in an operating room, performing a medical procedure on a patient in a medical treatment facility that is portable such as one that is erected to treated injured soldiers during battle, or in performing medical examinations, or alternatively repairing a watch or other instrument with small parts. 
         [0027]    The task light  10  includes a plurality of light sources  12 , including in the exemplary embodiment shown in  FIG. 1 , a first light source  12   a , a second light source  12   b  and a third light source  12   c . The light  10  includes a support structure  14  which supports the light sources  12 . 
         [0028]    In one aspect, the task light  10  is advantageous in that it permits a user  16  to position it substantially at head level in a position such that a light source  12  is on one side of the head (shown at  18 ) of the user  16  and another light source  12  is on the other side of the head  18  of the user  16 , while releasing a reduced amount of heat to the user  16  relative to some prior art lights. This position may be advantageous to the user  16  in that it permits the light  10  to be positioned dose to the work surface, shown at  19 , which provides increased brightness at the work surface  19 . 
         [0029]    The light sources  12  may each be made up of one or more light elements  20  which may be, for example, light emitting diodes (LEDs)  20 . For example, each light source  12  may contain seven LEDs  20 . The LEDs  20  may be arranged in an offset pattern, which permits relatively tighter clustering, as shown in  FIG. 2 . For example, the LEDs  20  may be arranged in a first row of two LEDs  20 , a middle or second row of three LEDs  20  in an offset relationship with the LEDs  20  in the first row and a third row of two LEDs  20  that is offset from the second row of LEDs  20 , such that the seven LEDs  20  form a hexagon shaped cluster. 
         [0030]    The LEDs  20  may include one or more first LEDs  20   a  and one or more second LEDs  20   b . The first LEDs  20   a  are adapted to emit light at a first colour temperature eg. 5500 degrees Kelvin, and the second LEDs  20   b  are adapted to emit light at a second colour temperature, eg. 3500 degrees Kelvin. For example, in the embodiment shown in  FIG. 2 , each light source  12  includes four LEDs (arbitrarily referred to as first LEDs  20   a ) which emit light at a colour temperature of 5000 degrees Kelvin (white light) and three LEDs (arbitrarily referred to as second LEDs  20   b ) which emit light at 3500 degrees Kelvin (amber or yellow light). 
         [0031]    Each light source  12  may be controlled in any suitable way. For example, the light  10  may have a main power switch  62  which controls power to the light  10  from a power source (not shown). The light  10  may further include a second LED power switch  64  which may be positionable in a first position and a second position. In the first position, the second LED power switch  64  operates the second LEDs  20   b  at a selected low level of power. In the second position, the second LED power switch  64  operates the second LEDs  20   b  at a selected low level of power. Regardless of the position of the second LED power switch  64  the one or more first LEDs  10   a  may operate at high power. For example, the first LEDs  20   a  may have a colour temperature of 5500 degrees Kelvin and the second LEDs  20   b  may have a colour temperature of 3500 degrees Kelvin. 
         [0000]    The light made up of the first LEDs  20   a  in combination with the second LEDs  20   b  may have a colour temperature of approximately 5000 when the second LED power switch  64  is in the first position and a colour temperature of approximately 4300 degrees Kelvin when the second LED power switch  64  is in the second position. Other control logic may alternatively be used however instead of the aforementioned. Generally speaking the color temperature is adjusted by means of varying the pulse frequency of white and amber LEDs. Optionally, the whites may be at full power consistently and the ambers may have two settings one at full power (frequency) another which slow their pulse down (by lowering current) so that there is less amber light in the mix. 
         [0032]    For the light  10  shown in  FIG. 2  with three light sources  12 , each having four first LEDs  20   a  and three second LEDs  20   b , the overall output strength of the light  10  may be approximately 6500 lux at a distance of 1 m. Optionally, the output is a 5″ diameter spot of light optionally with a minimum intensity of 15000±2000 lux. 
         [0033]    The output power of the light sources  12  may be expressed also in terms of wattage. Each of the LEDs  20  that make up the light sources  12  may be a 3 W LED. 
         [0034]    Referring to  FIG. 3 , the LEDs  20  may be connected to a circuit board  22  by any suitable means. For example, the LEDs  20  may each have two electrical conduits  24  which connect physically and electrically to electrical conduits  26  traced in the circuit board  22 . The LEDs  20  may otherwise have no contact with the circuit board  22 , and may instead pass through apertures  28  provided in the circuit board  22 . Each LED  20  may have a heat conduction surface  30 , which may be positioned on the aft end shown at  32 . The heat conduction surface  30  may be in contact with a first end  34   a  of a heat transfer member  34 . The heat conduction surface  30  may be made from a relatively conductive material, such as a suitable metal, to facilitate heat transfer out of the LED  20  and into the heat transfer member  34 . Thermally conductive adhesive, known as thermal compound, may be used to adhere the LED  20  to the heat transfer member  34  to facilitate heat transfer therebetween. The thermal compound is preferably applied in such a way so that there are no voids therein between the heat conduction surface  30  and the heat transfer member  34 . Alternatively, the LEDs  20  may directly contact the circuit board  22 , which is in turn in contact with the heat transfer member via the thermal compound 
         [0035]    The heat transfer member  34  transfers heat away from the LEDs  20  and towards a plurality of a plurality of heat dissipation devices  36  that are in thermal connection therewith. The thermal dissipation devices  36  transfer heat from the heat transfer member  34  into the environment. The heat transfer member  34  may be made from any suitably thermally conductive material such as a metallic material, such as, for example, Aluminum, which may be anodized. 
         [0036]    The heat transfer member  34  includes a first surface  38   a  and an opposing second surface  38   b . The first surface  38   a  is the surface that contacts the heat conduction surfaces  30  of the LEDs  20 . 
         [0037]    As shown in  FIG. 2 , the light  10  may include a first heat dissipation device  36   a  and a second heat dissipation device  36   b  that are associated with each light source  12 . The heat dissipation device  36   a  may be positioned on the opposing second surface  38   b  of the heat transfer member  34  in general alignment with the set of one or more LEDs  20  in each light source  12 . Thus, at least some heat is transferred from the LEDs  20  through the thickness of the heat transfer member  34  and into one of the heat dissipation devices  36   a.    
         [0038]    The heat dissipation device  36   b  may contact the heat transfer member  34  at a point that is spaced from the light source  12 . For example, the heat dissipation device  36   b  may contact the heat transfer member  34  proximate a second end, shown at  34   b . Thus, at least in part, heat is transferred away from the LEDs  20  along the length of the heat transfer member  34 , ie. along the plane of the heat transfer member  34 . 
         [0039]    Referring to  FIG. 3   a , the heat dissipation device  36   a  may be made up of a heat sink  40  and a fan  42 . The heat sink  40  may be made from a thermally conductive material, such as a metallic material, such as Aluminum, and includes a base  44  which contacts the heat transfer member  34  to draw heat therefrom, and a plurality of extensions  46  each extend outwards from the base  44  and which act to increase the surface area from which heat can escape into the environment. To increase the rate at which heat is dissipated through the extensions  46 , the fan  42  is positioned to move air through the extensions  46 . In this way the fan  42  causes active convection of heat from the extensions  46 . 
         [0040]    The fan  42  may be configured to draw air from the environment and to blow the air through the extensions  46  and back out to the environment. Alternatively, the fan  42  may be configured to draw air in from the environment through the extensions  46  and then through the fan itself  42  and then back out to the environment. 
         [0041]    The heat dissipation devices  36   b  may be similar to the heat dissipation devices  36   a , and may also each include a heat sink  48  and a fan  50 . The heat sinks  48  and fans  50  may be similar in structure to the heat sinks  40  and the fans  42 , however the heat sinks  48  and fans  50  may be sized to deal with the quantity of heat that reaches them via the heat transfer member  34 , which may be different than the amount of heat that reaches the heat dissipations devices  36   a  from the light sources  12 . 
         [0042]    The heat transfer members  34  may all be integrally connected to each other. For example, they may extend outwardly from a common hub  52 . As a result, the heat transfer members  34  and hub  52  are thermally connected together as part of a single integral member  54  and are therefore able to balance out to some degree any heat generation differences that might exist between the light sources  12 . For example, if one of the light sources, for example  12   a , generates more heat than the other heat sources,  12   b  and  12   c  in this example, or if the light source ( 12   a  in this example) is unable to dissipate heat as effectively as the others, then excess heat will be transferred through the integral member  54  towards the heat dissipation devices  36  associated with the other light sources  12 . In this way, an increase in the temperature of one of the light sources  12  is at least partially dampened out by increasing the amount of heat that is dissipated by at least several of the heat dissipation devices  36 . 
         [0043]    As a result of the thermal connection between all of the heat transfer members  34 , the heat dissipation devices  36   b  may be replaced by a single heat dissipation device, which is sized to dissipate heat transferred thereto from all of the heat transfer members  34 . 
         [0044]    To reduce the risk of damage to the LEDs  20  as a result of temperature, a thermistor may be included to sense a temperatures associated with each light source, so that the thermistor switches off its associated light source if the sensed temperature exceeds a selected limit. The thermistor may be in contact with the heat transfer member  34  proximate its first end  34   a  to provide temperature information regarding the light source  12  positioned at the first end  34   a.    
         [0045]    The integral heat balancing member  54  may act as the structural support  14  that supports the light sources and heat dissipation devices  36 . The configuration of the integral heat balancing member  54  may be as shown in  FIG. 1 , including the common hub  52  and the heat transfer members  34  which act as arms that extend outwards from the common hub a selected number of degrees away from each other. For example, in the embodiment shown in  FIG. 1 , the heat transfer members  34  extend outwards 120 degrees apart. 
         [0046]    By acting as a structural support and a heat transfer member, the member  54  provides two functions simultaneously and thus serves to reduce the overall weight of the device. Additionally, the shape of the member  54  is such that it provides sufficient thermal conductivity for removing heat from the light sources  12 , but omits portions that would otherwise fill the spaces between the arms  34  since they do not transfer heat directly from one of the light sources  12  to one of the heat dissipation devices  36   b . This further reduces the overall weight of the light  10 . As a result of these and possibly other measures, the light  10  may weigh less than 3 lbs and may possibly weigh less than 2.5 lbs. As a result, the light  10  is adapted for use in portable medical care facilities, such as those facilities which are erectable in battle by the military to quickly provide care for an injured person. Such a facility is sometimes referred to as a Forward Resuscitative Surgery System (FRSS). Typically prior art lights which are used in such facilities have a single light source, which is not an LED. 
         [0047]    As shown in  FIG. 5 , a space  56  is formed between each adjacent pair of light sources  12 , wherein the space  56  is sufficiently large in width (between each adjacent pair of arms  34 ) and in depth (radially between the light sources  12  and the hub  52 ) that the user  16  can position the light  10  so that one of the light sources  12  is on one side of the head  18  of the user  16  and another of the light sources  12  is on the other side of the head  18  of the user  16 . For example, the width of the space  56  between housings surrounding the light sources  12  may be approximately 7.2 inches, and the depth of the space  56  may be, for example, from the outside of the LEDs  20  to the radially outer edge of the hub  52 , shown at  60 , may be about 1.8 inches. The horizontal distance from the outer edge  60  of the hub  52  to the centre of convergence for the light sources  12  is approximately 1.6 inches. 
         [0048]    As a result, the user  16  can position the light  10  at head level above the work surface  19  ( FIG. 1 ), while having light sources  12  on either side of the head  18  of the user  16 . Positioning the light sources  12  at head level above the work surface  19  provides stronger illumination of the work surface  19  relative to light sources that are positioned above the head  18  of the user  16 , simply as a result of the closer proximity to the work surface  19 . Having light sources  12  on either side of the user  16  in combination with a light source  12  in front of the head  18  of the user  16 , as shown in  FIG. 1 , is considered advantageous by some users who feel that it provides better illumination of the work surface  19  relative to some prior art lights with light elements that are all positioned forward of the head  18  of the user  16 . 
         [0049]    By using LEDs  20  instead of other lighting elements such as halogen lighting elements, less heat is generated at each light source  12  relative to the amount of light provided. This permits a relatively greater amount of illumination to be provided while keeping the temperature at an acceptable level for the user  16 . Where ambient temperature is about 72 degrees Fahrenheit, the temperature of the housing elements  68 ,  70  and  72  that are shown around the light sources  12  and the first heat dissipation devices  36   a  can be kept below 130 degrees Fahrenheit. Optionally, the temperature of the contact surfaces of the housing elements  68 ,  70  and  72  can be kept below 100 degrees Fahrenheit. These temperatures apply in steady state conditions, which may occur within approximately 20 minutes of turning the light  10  on. 
         [0050]    In addition to the relatively cool temperatures of the contact surfaces of the housings  68 ,  70  and  72 , the light emitted by the LEDs has a relatively low component in the infra-red range and as a result, the LEDs do not emit significant quantities of heat. As a result, the tissues of the patient being illuminated are not subject to damage from drying out as a result of being illuminated by the light  10 . 
         [0051]    In addition to the heat transfer element  34  being configured to transfer heat from the light sources  12  to the heat dissipation units  36   a  and  36   b , the heat transfer element  34  releases heat by itself into the environment. This release of heat is further assisted by having significant fraction of the surface area of the heat transfer member  34  exposed directly to the environment. 
         [0052]    The light sources  12  may each be positioned at a selected angle with respect to the general plane of the light  10  so that their emitted light converges at a selected distance from the plane of the light  10 . The plane of the light  10  is, in the exemplary embodiment shown in  FIG. 1 , parallel to the plane of the hub  52 . The angle of the light sources  12  may be, for example, 10 degrees from the plane of the light  10 . To achieve the selected angle of the light sources  12 , the arms  34  may be bent by a suitable amount at a selected distance horizontally (ie. in the plane of the light  10 ) from the center of the light  10 , such as for example, about 3.5 inches horizontally from the center of the light  10 . Alternatively, in another embodiment that is not shown, the arms  34  may be co-planar with the hub  52  along their entire length and the light sources  12  may be mounted at a selected angle to the arms  34 . 
         [0053]    A light-directing element  66  may be provided which receives emitted light from the LEDs  20  and provides a selected cone angle to the emitted light. The cone angle may be, for example, 6 degrees. With this cone angle, the emitted light from the light sources  12  forms a generally circular relatively uniformly bright area on the work surface of about 8 inches in diameter, optionally about 5 inches. 
         [0054]    The light sources  12  may be positioned at a selected radius from the centre of the light  10  so that the light coming from the three light sources  12  converges at a distance of approximately 1 m from the plane of the hub  52 . For example, the light sources  12  may be positioned within a radius (or distance in embodiments wherein the light sources  12  are not positioned on a circular arc) of approximately 6.2 inches from the center of the light  10 . Generally, the light sources  12  may be positioned within a radius that is within a range of about 5.2 to about 7.2 inches from the center of the light  10 , while still producing a generally circular disc having a diameter of about 8 inches. 
         [0055]    The selected distance from the plane of the light  10  at which the emitted light converges from the light sources  12  may be selected so that it corresponds generally to the distance between the level of the head  18  of a typical user  16  and the typical level of the work surface  19 . 
         [0056]    Reference is made to  FIG. 4 , which shows a sectional view of the light  10 . The circuit board  22  may be fixed to the heat transfer member  34  by thermal compound, and may also be fixed using screws or the like. Electrical conduits shown at  74  may extend from the circuit board  22  along the heat transfer member  34  to a main circuit board  76  positioned at the hub  52 . The main circuit board  76  may be responsible for conditioning incoming power for use by the LEDs  20 . Electrical conduits  78  may extend from the main circuit board  76  out of the light  10  for connection to a power source. The conduit  78  may form part of the interface that connects with a flexible arm that supports the task light. 
         [0057]    A housing  80  may be provided over the heat dissipation devices  36   b , the main circuit board  76  and the switches  62  and  64 . The housing  80 , and the housings  68 ,  70  and  72  may all be made from a suitable polymeric material which is relatively thermally non-conductive. 
         [0058]    Variations in cone angle and converging distance are contemplated. 
         [0059]    Referring to  FIG. 4 , the light  10  may be configured to receive a handle  82 , which may be a standard sterile handle which is in common use and which has a male thread that mates with a female thread  84  provided in a removable handle mount  86 . In the event that a different handle becomes a common standard in the industry, and it has a different means of mounting to a light, the handle mount  86  may be removed and replaced with a new handle mount that is configured to receive the new handle. The handle mount  86  may be connected to the rest of the light  10  in any suitable way. For example, the handle mount  86  may be press-fit in a receiving aperture  88  in the housing  80 . 
         [0060]    Reference is made to  FIG. 6 , which illustrates a light  100  in accordance with a second embodiment of the present invention. The light  100  may be similar to the light  10  ( FIG. 1 ), except that the light  100  includes four light sources  12 . Each light source  12  may have a heat transfer member  34  associated therewith and first and second heat dissipation devices  36   a  and  36   b  associated therewith. The spaces  102  and  104  may be provided between adjacent pairs of light sources  12 , which are sufficiently large in width and depth to permit the light sources  12  to be positioned on either side of the head  18  of the user  16 . 
         [0061]    A light in accordance with an embodiment of the invention may have as few as two light sources. Alternatively it may have five or more light sources. 
         [0062]    The term “opposite sides of the head” is used to define positions of the lights sources relative to the head of the user and is understood to mean that the support structure together with the light sources define a notch-like space for head placement that is large and deep enough for the user to position his/her head between the light sources to an extent that the light sources are proximate to the respective coronal sutures on either side of the head. 
         [0063]    While the above description provides example embodiments, it will be appreciated that the present invention is susceptible to modification and change without departing from the fair meaning and scope of the accompanying claims. Accordingly, what has been described is merely illustrative of the application of aspects of embodiments of the invention. Numerous modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described herein.