Abstract:
An LED-UV lamp that is easily interchangeable within a UV-curing process and scalable in length with a fine resolution so that it is easily customizable to any UV-curing application. The LED-UV lamp may incorporate multiple rows of LEDs and contain corresponding optics that effectively deliver radiant power to a substrate at distances of several inches.

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS 
     This application claims priority under 35 U.S.C. §119 (e) to, and hereby incorporates by reference, U.S. Provisional Application No. 61/237,455, filed 27 Aug. 2009, U.S. Provisional Application No. 61/267,021, filed 5 Dec. 2009, and U.S. Provisional Application No. 61,237,436, filed 27 Aug. 2009. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to LED-UV lamps. More particularly, the invention is suitably used in the application of UV-curing of inks, coatings, and adhesives having UV photo initiators therein. 
     2. Background 
     UV LED lamps are permanently mounted within the UV-curing process. Depending upon the optics used, the UV LED lamps can be required to be located at a specific distance from the substrate so that uniformity and intensity are optimized. Some UV LED lamps are scalable in length with coarse resolution. 
     UV LED lamps are mounted into a UV-curing process in a manner that makes them difficult and time consuming to remove for cleaning, maintenance, or the like. UV LED lamps are mounted in fixed positions within the UV-curing process where the location within the position is often determined by the process machinery into which the UV curing LED lamps are being integrated. 
     Different positions within the UV-curing process could require the UV LED lamps to be at different locations with respect to the substrate. A conflict could arise between the location required by the optics of the lamp and the location determined by the machinery of a UV-curing process which scenario could render the UV LED lamp unsuitable for placement in particular positions within a UV-curing process. 
     If a lamp is required at an alternate location, either an existing lamp must be uninstalled from an existing location and reinstalled at the desired location which option would only be suitable if the location required by the optics of the UV LED lamp is compatible with the location available in the desired position, or a new lamp must be purchased possibly with redesigned optics. UV LED lamps of different wavelength would also not be easily interchangeable. 
     The coarse resolution in length scalability could result in the scenario where the lamp length options that are available are either too short or too long for a particular application which may make the UV LED lamps difficult or impossible to install into some UV-curing applications. For example, if the length of a UV LED lamp was scalable in 3 inch increments, and a 40 inch lamp was required, the options would either be 39 inches (13×3 inches), or 42 inches (14×3 inches). The 39 inch lamp would be too short and could result in uncured product at the ends of the lamp. The 42 inch lamp could be too long to fit into the envelope that is available within the UV-curing process. 
     SUMMARY OF THE INVENTION 
     LEDs are mounted onto short subassembly segments that may be produced in assorted lengths which segments are then easily mounted into the LED-UV module in a row running along the length of the module. 
     Assembling the LEDs in segments that are easily mounted into the LED-UV module would simplify the process of LED replacement and possibly make the process less expensive. If an LED fails, the segment whereon the failed LED had been assembled can be disconnected, removed, and then a new segment can be installed in its place. 
     The LEDs may degrade as they get older and their output power may decrease below an acceptable level for their application. In this case the owner of the LED-UV lamp would have the option of replacing the segments with new ones as opposed to replacing the whole module. 
     LEDs are solid state semiconductor devices. The efficiency and power output of LEDs can increase from one generation to the next as scientific breakthroughs are made and manufacturing processes improve. The owner of the LED-UV module would have the option to easily upgrade the module by swapping out old segments for new ones with improved operating characteristics. 
     Providing the segments in an assortment of lengths could enable the length of the row of segments to be scalable with a finer resolution than what may be possible if all of the segments where the same length, while at the same time the total number of parts required to assemble the row of LEDs could be reduced. For example, the segments could be configured in a 3 inch version, a 4 inch version, and a 6 inch version. A 12 inch row of segments could then be assembled by connecting 2 of the 6 inch segments. A 13 inch row of segments could be assembled by connecting a 6 inch segment, a 4 inch segment, and a 3 inch segment. A 14 inch row of segments could be assembled by connecting a 6 inch segment and two 4 inch segments. The row of LEDs could be assembled in a variety of lengths with a 1 inch resolution. On the other hand, if only one segment was made, in a 3 inch version for example, the resolution of the possible LED row lengths would be 3 inches, resulting in fewer length options available for customizability. The segment could be made in a 1 inch version to achieve a 1 inch resolution, but doing so could increase the complexity of the assembly by increasing the number of parts required to construct a row. 
     The main module body contains a surface extending the length of the module, whereon the LED segments can be mounted. 
     This surface provides correct positioning and easy mounting of the LED segments. 
     The main module body contains an integral heat sink feature with coolant passages that run the length of the module and are positioned such that they pass near the surface whereon the LED segments mount. 
     The heat sink feature provides a simple means of effectively extracting heat from the LEDs. This maintains the LED junction temperature at an acceptably low level thus maximizing the life of the LEDs. 
     The module is designed so that it is interchangeable and can therefore be quickly and easily installed into or removed from docking ports that are rigidly mounted into a UV-curing process without the use of tools. 
     Interchangeability allows the modules to be easily removed from the UV-curing process for cleaning, repair, maintenance, or the like. LED-UV modules of different wavelengths can be installed into the UV-curing process and the modules can be moved between different locations within the UV-curing process as long as there is a docking port available. Removal and installation of the LED-UV modules from the associated docking ports within a UV-curing process is a tool-less procedure and can be done by a person of no extraordinary skill. 
     All necessary connections (e.g. power, communication, liquid cooling) are made automatically upon installation of the LED-UV module into a docking port, and then disconnected automatically during the removal of the LED-UV module from a docking port. 
     Automatic engaging and disengaging of the connections between the LED-UV module and the docking port upon insertion and removal of the LED-UV module ensure that the connections are made properly, save time, and make the overall operation of the UV-curing process more convenient for the user. 
     All connection devices (e.g. electrical pins, coolant valves) are positioned such that they do not protrude beyond the outer surfaces of the LED-UV module. 
     Designing the connections such that they do not protrude beyond the outer surfaces of the module protects them from damage. With the LED-UV module being designed in a manner that the module is easily removable from the UV-curing process, the possibility of damage to the connections that could result from handling the module will be significantly reduced. 
     The LED-UV module can incorporate a common optical design using a parabolic or elliptical trough reflector that allows for varying distances and mounting locations with respect to the substrate being cured without a significant loss of uniformity or optical (irradiant) intensity. 
     LEDs, by themselves, typically exhibit a Lambertian radiation pattern in which the intensity of the light output by the LED chip is directly proportional to the cosine of the angle between the point of observation and the surface normal of the LED chip. An elliptical or parabolic trough reflector can effectively gather the light and project it onto a substrate that is positioned at varying distances (i.e. from fractions of an inch to several inches) from the base of the LED-UV module with a minimal loss in intensity and in a very uniform manner. 
     Without the use of a reflector, the LED-UV module may need to be placed at either a fixed, optics-dependent distance from the substrate or much closer to the substrate than would be allowable by some UV-curing processes or some positions within a UV-curing process. One example could be in a sheet-fed printing press. In sheet-fed printing, it is typically desirable to locate one or more LED-UV modules immediately following the application of one or more UV-curable inks following the inking units of the printing machine in order to “pin” or “dry” the UV-curable inks or spot varnishes prior to the application of a UV-curable coating at the end of the press prior to the delivery of sheets onto a pile. For inking unit curing locations (immediately following the inking units), it would be desirable to locate the LED-UV modules closer (typically 1 to 3 inches) to the substrate for the benefit of easier mechanical mounting in order to fit within the space constraints provided by various makes and models of printing machines. However, at end-of-press curing locations, the method of sheet transfer provided by most printing machines prohibits closer mechanical location through the end-of-press sheet delivery area and would require the LED-UV module to be mounted as far as 3 to 5 inches away from the substrate. If the LED-UV module were placed too close to the substrate it would collide with the moving machinery of the printing press. The use of reflector style optics enables a single, interchangeable design of the LED-UV module of the invention to be placed in multiple docking or mounting positions at differing distances to the substrate without significant loss of optical uniformity or radiant intensity within a UV-curing process that would otherwise have inaccessible or impractical mounting locations and/or require multiple, non-interchangeable optical designs of the LED-UV modules between the various positions of the process. 
     The LED-UV modules would be available in a variety of UV wavelengths and each wavelength module would be interchangeable with the others and could therefore be applied to any docking port within the UV-curing process. 
     Different types of UV curable products can cure most effectively when irradiated by different wavelengths of UV light. For example, clear products may cure most effectively with longer wavelength UV light, while darker, more heavily pigmented products may cure more effectively with shorter wavelength UV light. Overall system performance may be maximized by the ability to interchange LED-UV modules of different wavelength within the UV-curing process depending upon the preferences of the UV-curable product that is being cured. 
     The LED-UV module could incorporate multiple, adjacent, parallel rows of LEDs where each row shines into a corresponding trough reflector. 
     Incorporating multiple, adjacent, parallel rows of LEDs where each row shines into a corresponding trough reflector would increase the radiant power output by the LED-UV module by a factor equal to the number of rows of LEDs. A single lamp of this embodiment could have the same radiant power output as multiple lamps of the single row embodiment with the added advantages of lower cost and smaller form factor compared to multiple lamps of the single row embodiment. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an isometric view of one embodiment of the LED-UV module of the invention. 
         FIG. 2   a  is a top view of the embodiment of  FIG. 1 . 
         FIG. 2   b  is a side view of the embodiment of  FIG. 1 . 
         FIG. 2   c  is an end view of the embodiment of  FIG. 1 . 
         FIG. 3  is a cross section view of the embodiment of the LED-UV module shown in  FIGS. 1 and 2  along line A-A of  FIG. 2   b.    
         FIG. 4  is a perspective view of one embodiment of an LED segment assembly of the invention. 
         FIG. 5  is a cross sectional view of one embodiment of the application of a trough reflector to aid in the transference of UV light from the LEDs onto the substrate. 
         FIG. 6  is an isometric view of another embodiment of the LED-UV module of the invention incorporating a plurality of adjacent, parallel rows of LEDs and multiple trough reflectors. 
         FIG. 7   a  is a top view of the LED-UV module shown in  FIG. 6 . 
         FIG. 7   b  is a side view of the LED-UV of  FIG. 6 . 
         FIG. 7   c  is an end view of the LED-UV module shown in  FIG. 6 . 
         FIG. 8  is a cross section view of the embodiment of the LED-UV module shown in  FIGS. 6 and 7   a - c  along line A-A of  FIG. 7   b.    
         FIG. 9  is an illustration of one embodiment of the application of a plurality of trough reflectors to aid in the transference of UV light from the LEDs onto the substrate and to multiply the available radiant power. 
     
    
    
     It is understood that the above-described figures are only illustrative of the present invention and are not contemplated to limit the scope thereof. 
     DETAILED DESCRIPTION OF THE INVENTION 
     The following is a description of possible embodiments of the LED-UV module of the invention. The examples and figures that follow are intended to teach a person skilled in the art how to effectively design and implement the present invention, but are not intended to limit the scope of the invention. The features and methods disclosed in the detailed description may be used separately or in conjunction with other features and methods to provide improved devices of the invention and methods for making the same. The features and methods disclosed in this detailed description may not be necessary to practice the invention in the broadest sense, but are provided so that a person of skill in the art may further understand the details of the invention. 
     Another description of the LED-UV lamp of this invention, as well as a docking system accommodating such lamp, is present in U.S. patent application Ser. No. 12/868,827, entitled Interchangeable UV LED Curing System, and filed concurrently with this application, the entire disclosure of such application hereby incorporated by reference. 
     Referring to  FIGS. 1 ,  2   a - c , and  3 , an LED-UV module  100  is shown having electrical connections  102 , coolant valves  104 , a module body  106 , a module cover  108 , a connection end cap  110 , a cross-over end cap  112 , alignment pins  114 , a transparent cover  116 , a trough reflector  118 , coolant passages  120 , LED segments  122 , and a surface  124  on the module body  106  to mount the LED segments  122 . 
     The electrical connections  102  would be located on the connection end  126  of the LED-UV module  100  and may be mounted onto the connection end cap  110 . To protect the electrical pins  102  from damage during handling of the LED-UV module  100 , the electrical connections  102  could be mounted to the connection end cap  110  in a recessed fashion so that they do not protrude beyond the outer surfaces of the connection end cap  110 . The electrical connections  102  would be used to transfer power and possibly communications from the LED-UV module  100  to mating electrical connections that would be present in the docking ports within the UV-curing process. The electrical connections could be pin and socket type connections. 
     The coolant valves  104  would be located on the connection end  126  of the LED-UV module  100  and may be mounted onto the connection end cap  110 . To protect the coolant valves  104  from damage during handling of the LED-UV module  100 , the coolant valves  104  could be located on the connection end cap  110  such that they do not protrude beyond the outer surfaces of the connection end cap  110 . The coolant valves  104  would connect to mating coolant valves that would be present in the docking port and would provide a supply and return for cooling fluid to flow through the LED-UV module  100 . The coolant valves  104  and the mating coolant valves in the docking port could be spring actuated poppet style valves that would automatically be pushed open when they are engaged, and automatically spring closed when they are disengaged. 
     The module body  106  would be the main supporting component of the LED-UV module  100 . Two significant features on the module body  106  could be the surface  124  that locates the LED segments  122 , and the coolant passages  120 . The module body  106  could support one edge of the transparent cover  116 . The module body  106  could be made of an extrusion out of a material that is a good heat conductor such as aluminum. 
     The module cover  108  would serve as the final component of the LED-UV module  100  assembly and cover all of the internal components. The module cover  108  could contain a feature that would hold the trough reflector  118  in the correct position and shape. The module cover  108  could support one edge of the transparent cover  116 . The module cover  108  could be made of an extrusion and the material could suitably be the same as the material of the module body  106 . 
     The connection end cap  110  would serve as the mounting structure for the electrical connections  102 , coolant water valves  104 , and the alignment pins  114 . The connection end cap  110  would mount to the appropriate end of the module body  106  forming the connection end  126  of the LED-UV module  100 . Power and communications would pass through the connection block  110  into the inside of the LED-UV module  100  through the electrical connections  102 . Liquid coolant would flow between the coolant valves  104  and the coolant passages  120  at the interface  128  where the connection block  110  mounts to the module body  106 . This interface may be sealed by a gasket such as an o-ring to prevent liquid coolant from leaking at the interface  128 . 
     The cross-over end cap  112  would mount to the end of the module body  106  that is opposite the connection block  110  forming the cross-over end  130  of the LED-UV module  100 . The cross-over end cap would contain a passage that would connect one of the coolant passages  120  to the other thus forming a circuit for liquid coolant to flow into the LED-UV module  100  through one of the coolant valves  104 , through one of the water passages  120 , through the passage in the cross-over end cap  112  through the other of the water passages  120 , and then out of the LED-UV module  100  through the other of the coolant valves  104 . The interface  132  between the cross-over end cap  112  and the module body  106  could be sealed with a gasket such as an o-ring to prevent liquid coolant from leaking at the interface  132 . 
     The alignment pins  114  would be located on the connection end of the LED-UV module and may be mounted to the connection block  110 . The alignment pins  114  could serve to align the connections  102 ,  104  prior to their engagement with the mating connections present in the docking port. 
     The transparent cover  116  would most suitably be made of a durable material that would be highly UV transparent such as quartz, glass, acrylic, or the like. The transparent cover  116  would serve as a protective window that would protect the internal components of the LED-UV module while allowing the light generated by the LEDs to pass through the transparent cover. The transparent cover could be supported on one edge by the module body  106  and supported on the opposite edge by the module cover  108 . The ends  134  of the transparent cover  116  could be trapped by the connection end cap  110  on one end and the cross-over end cap  112  on the other. 
     The reflector  118  would be made of a highly UV reflective material such as acrylic mirror, polished metal, or the like, and could be formed into shape prior to installation into the LED-UV module  100 . The reflector  118  could be held in position and shape by a mating feature in the module cover  108 . The reflector could be trough shaped and may incorporate a parabolic or elliptical geometry that would transfer the UV light emitted by the LEDs onto the substrate. 
     The coolant passages  120  would run the length of the module body  106  and be positioned so that they pass near the surface  124  whereon the LED segments  122  mount. The coolant passages  120  facilitate the removal of heat generated by the LEDs and may be dimensioned and located such that the temperature of the module body  106  is essentially uniform over a length of such module. Heat generated at the P/N junctions of the LEDs is conducted from the LED segments  122 , into the module body  106  where it is transferred to the liquid coolant by means of convection at the surfaces of the coolant passages  120 . The coolant passages could contain fin features  136  that protrude into the liquid coolant. The fin features  136  would serve to increase the convective surface area of the coolant passages  120  as well as generate turbulence in the liquid coolant that would increase the associated convection coefficient. The fin features could also increase the rate of heat conduction through the module body. The presence of fin features  136  in the coolant passages  120  would serve to increase the rate of heat convection from the module body  106  to the liquid coolant, ultimately resulting in lower LED junction temperatures. Lower LED junction temperatures could enable longer LED lifetimes. 
     One embodiment of an LED segment  122  is shown in  FIG. 4 . The LED segment  122  could consist of a heat transfer plate  138 , a plurality of LED packages or segments  140 , thermal interface material  142 , and fasteners  144  to attach the LED packages  140  to the heat transfer plate  138 . The LED packages  140  could be off-the-shelf packages or they could be custom designed. The LED package  140  specifications could suitably be low thermal resistance, high powered UV output, and quick disconnect power terminals  146 . The LED segment  122  could contain mounting features such as bolt holes  148  to enable fastening to the module body  106  in a manner that maximizes heat transfer from the LED segment  122  to the module body  106 . Multiple LED segments  122  could suitably be mounted to the module body in a lengthwise, end-to-end configuration to form a long row of LEDs. The LED segments  140  would be designed in a manner that maximizes the LED line density (i.e. number of LEDs per inch) and the LED segments  140  could be designed in an assortment of lengths which would enable finer length resolution when assembling the LED segments  140  in a lengthwise, end-to-end configuration to form a long row of LEDs. The finer length resolution would facilitate customizability for a variety of different length UV-curing applications. Providing the segments  140  in an assortment of lengths could enable the length of the row of segments  140  to be scalable with a finer resolution than what may be possible if all of the segments  140  were the same length, while at the same time the total number of parts required to assemble the row of LEDs could be reduced. For example, the segments  140  could be configured in a 3 inch version, a 4 inch version, and a 6 inch version. A 12 inch row of segments  140  could then be assembled by connecting 2 of the 6 inch segments. A 13 inch row of segments  140  could be assembled by connecting a 6 inch segment, a 4 inch segment, and a 3 inch segment. A 14 inch row of segments  140  could be assembled by connecting a 6 inch segment and two 4 inch segments. The row of LED segments  140  could be assembled in a variety of lengths with a 1 inch resolution. On the other hand, if only one segment  140  was made, in a 3 inch version for example, the resolution of the possible LED row lengths would be 3 inches, resulting in fewer length options available for customizability. The segment  140  could be made in a 1 inch version to achieve a 1 inch resolution, but doing so could increase the complexity of the assembly by increasing the number of parts required to construct a row. 
       FIG. 5  illustrates how the implementation of a trough reflector  118  could effectively transfer light  150  from the LEDs onto a substrate  152  at a distance  154  of several inches. This type of optical configuration would be very suitable for UV-curing applications wherein it is not possible to place the LED-UV module in close proximity to the substrate. 
     Some UV-curing applications may require more UV power than an LED-UV module  100  having a single row of LED segments  122  can provide. An alternative embodiment of the LED-UV module  100  of the invention could consist of two or more adjacent, parallel rows of LED segments  122  shining into separate trough reflectors  118 . 
     Referring to  FIGS. 6 ,  7   a - c , and  8 , an LED-UV module  200  is shown having electrical connections  202 , coolant valves  204 , a first module cover  206 , a second module cover  208 , a connection end cap  210 , a cross-over end cap  212 , alignment pins  214 , a transparent cover  216 , a plurality of trough reflectors  218 , coolant passages  220 , LED segments  122 , a heat sink  224 , and surfaces  226  on the heat sink  224  to mount the LED segments  122 . 
     The electrical connections  202  would be located on the connection end  228  of the LED-UV module  200  and may be mounted onto the connection end cap  210 . The electrical connections  202  would be used to transfer power and possibly communications from the LED-UV module  200  to mating electrical connections that would be present in the docking ports within the UV-curing process. The electrical connections could be pin and socket type connections. 
     The coolant valves  204  would be located on the connection end  228  of the LED-UV module  200  and may be mounted onto the connection end cap  210 . To protect the coolant valves  204  from damage during handling of the LED-UV module  200 , the coolant valves  204  could be located on the connection end cap  210  such that they do not protrude beyond the outer surfaces of the connection end cap  210 . The coolant valves  204  would connect to mating coolant valves that would be present in the docking port and would provide a supply and return for cooling fluid to flow through the LED-UV module  200 . The coolant valves  204  and the mating coolant valves in the docking port could be spring actuated poppet style valves that would automatically be pushed open when they are engaged, and automatically spring closed when they are disengaged. 
     The first module cover  206  would cover one side of the LED-UV module  200 . The first module cover  206  could contain a feature that would hold one of the trough reflectors  218  in the correct position and shape and the first module cover  206  could support one edge of the transparent cover  216 . The first module cover  206  could be made of an extrusion out of a material such as aluminum or plastic. 
     The second module cover  208  would cover the other side of the LED-UV module  200 . The second module cover  208  could contain a feature that would hold another of the trough reflectors  218  in the correct position and shape and the second module cover  208  could support the other edge of the transparent cover  216 . The second module cover  208  could be made of an extrusion out of a material such as aluminum or plastic. 
     The connection end cap  210  would serve as the mounting structure for the electrical connections  202 , coolant water valves  204 , and the alignment pins  214 . The connection end cap  210  would mount to the appropriate end of the LED-UV module  200  forming the connection end  228  of the LED-UV module  200 . Power and communications would pass through the connection block  210  into the inside of the LED-UV module  200  through the electrical connections  202 . Liquid coolant would flow between the coolant valves  204  and the coolant passages  220  at the interface  230  where the connection block  210  mounts to the heat sink  224 . This interface may be sealed by a gasket such as an o-ring to prevent liquid coolant from leaking at the interface  230 . 
     The cross-over end cap  212  would mount to the end of the LED-UV module  200  that is opposite the connection block  210  forming the cross-over end  232  of the LED-UV module  200 . The cross-over end cap  212  would contain a passage that would connect one of the coolant passages  220  to the other thus forming a circuit for liquid coolant to flow into the LED-UV module  200  through one of the coolant valves  204 , through one of the water passages  220 , through the passage in the cross-over end cap  212  through the other of the water passages  220 , and then out of the LED-UV module  200  through the other of the coolant valves  204 . The interface  234  between the cross-over end cap  212  and the module body  206  could be sealed with a gasket such as an o-ring to prevent liquid coolant from leaking at the interface  234 . 
     The alignment pins  214  would be located on the connection end of the LED-UV module and may be mounted to the connection block  210 . The alignment pins  214  could serve to align the connections  202 ,  204  prior to their engagement with the mating connections present in the docking port. 
     The transparent cover  216  would most suitably be made of a durable material that would be highly UV transparent. The transparent cover  216  would serve as a protective window that would protect the internal components of the LED-UV module while allowing the light generated by the LEDs to pass through the transparent cover  216 . The transparent cover  216  could be supported on one edge by the first module cover  206  and supported on the opposite edge by the second module cover  208 . The ends  234  of the transparent cover  216  could be trapped by the connection end cap  210  on one end and the cross-over end cap  212  on the other. 
     The reflectors  218  would be made of a highly UV reflective material and could be formed into shape prior to installation into the LED-UV module  200 . The reflectors  218  could be held in position and shape by mating features in the first and second module covers  206  and  208 . The reflectors  218  could be trough shaped and may incorporate a parabolic or elliptical geometry that would transfer the UV light emitted by the LEDs onto the substrate. 
     The coolant passages  220  would run the length of the heat sink  224  and be positioned so that they pass near the surface  226  whereon the LED segments  122  mount. The coolant passages  220  facilitate the removal of heat generated by the LEDs. Heat generated at the P/N junctions of the LEDs is conducted from the LED segments  122 , into the heat sink  224  where it is transferred to the liquid coolant by means of convection at the surfaces of the coolant passages  220 . The coolant passages could contain fin features  238  that protrude into the liquid coolant. The fin features  238  would serve to increase the convective surface area of the coolant passages  220  as well as generate turbulence in the liquid coolant that would increase the associated convection coefficient. The fin features  238  could also increase the rate of heat conduction through the module body. The presence of fin features  238  in the coolant passages  220  would serve to increase the rate of heat convection from the heat sink  224  to the liquid coolant, ultimately resulting in lower LED junction temperatures. Lower LED junction temperatures could enable longer LED lifetimes. 
       FIG. 9  illustrates how the implementation of a plurality of trough reflectors  218  could effectively transfer light  240  from the multiple, adjacent, parallel rows of LEDs onto a substrate  242  at a distance  244  of several inches. This type of optical configuration would be very suitable for UV-curing applications wherein it is not possible to place the LED-UV module in close proximity to the substrate and where the power of multiple LED-UV lamps  100  is required in a single location. 
     The LED-UV modules  100 ,  200  of the invention could be produced in an assortment of models where each model would have a different peak wavelength, or could have a plurality of peak wavelengths, in its spectral output depending on the LEDs used in the LED segments  122 . To achieve a plurality of peaks in the spectral output of the LED-UV modules  100 , 200 , a mixture of LEDs of different UV wavelength could be used, in an alternating pattern, within each LED segment  122 . A single LED-UV module  100 , 200  with a single peak wavelength in its spectral output is contemplated to be within the spirit and scope of this invention. Additionally, a single LED-UV module  100 , 200  with a plurality of peak wavelengths in its spectral output is contemplated to be within the spirit and scope of this invention. 
     Having different models of LED-UV modules  100 , 200  available, each with a different peak wavelength output, or emitting a plurality of peak wavelengths, and where the LED-UV modules  100 , 200  are interchangeable within a UV-curing process would increase the flexibility of the UV-curing system. Many LED-UV lamps are available in an assortment of UV wavelengths and some with the option of multiple peaks in their spectral output. The LED-UV modules  100 , 200  of this invention would be designed such that they can be quickly inserted into and removed from a UV-curing process without the use of tools provided that the associated docking ports are mounted into the UV-curing process. A model of an LED-UV module  100 , 200  of one UV spectral output can be removed and a model of a different UV spectral output can be inserted in a matter of minutes by a person of no extraordinary skill. 
     A person of ordinary skill in the art will readily appreciate that individual components shown on various embodiments of the present invention are interchangeable to some extent and may be added or interchanged on other embodiments without departing from the spirit and scope of this invention. 
     Because numerous modifications of this invention may be made without departing from the spirit thereof, the scope of the invention is not to be limited to the embodiments illustrated and described. Rather, the scope of the invention is to be determined by the appended claims and their equivalents.