Patent Publication Number: US-2011058357-A1

Title: Led lighting assembly with leds having different viewing angles

Description:
RELATED APPLICATIONS 
     This patent application claims priority to U.S. Patent Application Ser. No. 60/999,037 filed Oct. 15, 2007, the entire contents of which are hereby incorporated by reference. 
    
    
     BACKGROUND 
     The present invention relates to a refrigerated merchandiser that includes a light source. More particularly, the present invention relates to a refrigerated merchandiser including a light emitting diode (LED) light source to illuminate a product display area. 
     In conventional practice, commercial businesses such as supermarkets and convenience stores are equipped with refrigerated merchandisers. These merchandisers may be open or provided with doors and are used for presenting perishable food or beverages to customers while maintaining the fresh food or beverages in a refrigerated environment. Some refrigerated merchandisers have a narrow profile or footprint so that the merchandiser can be placed in the convenience store or supermarket store without taking up a large area of the store. This narrow profile results in a product display area having less depth compared to a standard-sized merchandiser. Typically, the refrigerated merchandisers include a light source that illuminates the product display area for better marketing of the food product and for higher visibility to the customers. However, the shelves inside the narrow profile merchandiser extend closer to the front of the product display area and thereby closer to the light sources creating undesirable lighting effects. 
     Conventional refrigerated merchandisers typically include a fluorescent light source to illuminate the product display area. Some merchandisers include fluorescent light sources that are coupled to a mullion of the merchandiser to direct light generally toward the food product in the product display area. The effectiveness of fluorescent light sources is dependent on the temperature of the application where the fluorescent light sources are used. In colder temperature conditions, the fluorescent light source has less light output than in application of the fluorescent light source in warmer temperature conditions. As a result, fluorescent light sources that are coupled to the mullions can have substantially reduced effective illumination of food product within the product display area. 
     The fluorescent light sources used in conventional merchandisers are relatively large, and reduce the amount of space in the merchandiser that can be allocated to displaying food product. In refrigerated merchandisers that have a narrow footprint, the large fluorescent light sources further limit the space available in the product display area for displaying food product. The close proximity of the relatively large mullion-mounted fluorescent light sources to shelves in the refrigerated merchandiser provide an imbalanced, uneven illumination of the product display area. 
     Other refrigerated merchandisers include light emitting diode (LED) light sources that are mounted to a mullion of the merchandiser to illuminate the product display area. In narrow profile refrigerated merchandisers, the mullion-mounted LED light sources are placed in very close proximity to the shelves. The close proximity of the existing LED light sources to the shelves causes an uneven, imbalanced distribution of light into the product display area. The existing LED light sources in narrow profile merchandisers only effectively illuminate a portion of the food product on the shelves. This results in spotlighting some food product on the shelves, and leaving other food product partially or substantially obscured due to the lack of uniform illumination of the entire product display area. 
     SUMMARY 
     The invention provides an improved merchandiser configured to illuminate a product display area effectively and efficiently. In one construction, the invention provides an improved light source that enables improved illumination of the product display area and reduces the energy required to condition the products within the merchandiser. 
     In another construction, the invention provides a merchandiser that includes a case that defines a product display area and that includes a frame that has mullions. The mullions define at least one opening such that the food product within the product display area is accessible from the front of the case. The merchandiser also includes at least one shelf for supporting and displaying food product within the product display area, and a light assembly that is coupled to at least one of the mullions and that is positioned to illuminate the food product. The light assembly includes a first LED that has a first viewing angle and a second LED that has a second viewing angle that is smaller than the first viewing angle. 
     In yet another construction, the merchandiser includes a light assembly that is coupled to at least one of the mullions and that is positioned to illuminate the food product. The light assembly includes a first LED that has a first viewing angle, and a second LED that has a second viewing angle that is different from the first viewing angle. The first LED and the second LED are positioned adjacent each other such that the first LED and the second LED are arranged in an alternating orientation along a length of the light assembly. 
     In yet another construction, the invention provides a method of illuminating food product supported by a merchandiser that includes a case that defines a product display area. The method includes providing a light assembly that is coupled to a mullion of the case. The light assembly includes a first LED that has a first viewing angle and a second LED that has a second viewing angle that is different from the first viewing angle. The method also includes partially illuminating the product display area by directing relatively diffuse light from the first LED into the product display area, and partially illuminating the product display area by directing a relatively pointed source of light from the second LED into the product display area. 
     Aspects of the invention will become apparent by consideration of the detailed description and accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of an exemplary merchandiser. 
         FIG. 2  is a perspective view of a mullion light assembly of the merchandiser of  FIG. 1 , including a housing, a lens cover, and LED light sources. 
         FIG. 3  is an end view of the mullion light assembly of  FIG. 2 . 
         FIG. 4  is a perspective view of the housing and the LED light sources of  FIG. 2 . 
         FIG. 5  is an end view of the housing and the LED light sources of  FIG. 4 . 
         FIG. 6  is an end view of the lens cover of  FIG. 2 . 
         FIG. 7  is a perspective view of one of the LED light sources of  FIG. 5  including wide viewing angle LEDs and narrow viewing angle LEDs. 
         FIG. 8  is a schematic view of one of the wide viewing angle LEDs and one of the narrow viewing angle LEDs of  FIG. 7 . 
         FIG. 9  is an end view of a housing and a LED light source of another mullion light assembly of the refrigerated merchandiser of  FIG. 1 . 
     
    
    
     DETAILED DESCRIPTION 
     Before any constructions of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The invention is capable of other constructions and of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of “including,” “comprising,” or “having” and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. Unless specified or limited otherwise, the terms “mounted,” “connected,” “supported,” and “coupled” and variations thereof are used broadly and encompass both direct and indirect mountings, connections, supports, and couplings. Further, “connected” and “coupled” are not restricted to physical or mechanical connections or couplings. 
       FIG. 1  shows a merchandiser  10  for displaying food product (e.g., frozen food, fresh food, beverages, etc.) available to consumers in a retail setting (e.g., a supermarket or grocery store). The merchandiser  10  includes a case  15  that has a base  20 , side walls  25 , a case top or canopy  30 , and a rear wall  35 . At least a portion of a refrigeration system (not shown) can be located within the case  15  to refrigerate the food product. In other constructions, a heating system can be located within the case  15  to heat the food product. The area partially enclosed by the base  20 , the side walls  25 , the case top  30 , and the rear wall  35  defines a product display area  40 . The food product is supported on shelves  45  within the product display area  40 . 
     The case  15  includes a frame  50  adjacent a front of the merchandiser  10 .  FIG. 1  shows that the frame  50  includes vertical mullions  55  that define openings  60 , and doors  65  positioned over the openings  60 . The openings  60  and the doors  65  are configured to allow access to food product stored in the product display area  40 . The mullions  55  are spaced horizontally along the case  15  to provide structural support for the case  15 . Each mullion  55  is defined by a structural member that can be formed from a non-metallic or metallic material. A handle  70  is positioned along an edge of each door  65  to move the door  65  between an open position and a closed position. 
     Each door  65  includes a frame  75  that attaches a translucent member  80  to the door  65  to allow viewing of the food product from outside the case  15 . The translucent member  80  can be formed from glass, or alternatively, from other materials that are substantially translucent (e.g., acrylic, etc.). In some constructions, the case  15  includes a standard profile or footprint that has a depth (e.g., 41 inches) defined between the rear wall  35  and the doors  65 . Generally, in standard profile cases, the mullions  55  are spaced apart a distance (e.g., 6 inches) from ends of the shelves  45 . In other constructions, the case  15  may include a narrow profile or footprint to limit the area in the retail setting that is taken up by the merchandiser  10 . In these constructions, the case  15  has a relatively shorter depth (e.g., 37 inches) between the rear wall  35  and the doors  65  when compared with the depth of standard profile cases. In the cases  15  that have a narrow profile, the mullions  55  are spaced apart from the ends of the shelves  45  a relatively shorter distance (e.g., 2 inches) when compared to the distance between the mullions  55  and the shelves  45  in standard profile cases. Generally, the mullions  55  of the narrow profile cases  15  are located in very close proximity to the shelves  45 . 
       FIGS. 2 and 3  show a mullion light assembly  85  that can be attached to each mullion  55  of the case  15  to illuminate the product display area  40 . The mullion light assembly  85  includes a housing or shell  90 , a translucent lens or cover  100 , mirrors or specular members  105 , and light emitting diode (LED) light sources  110 . The housing  90  can be attached to each mullion  55  using a clip or retainer  115 , or another similar fastener. The clip  115  can be coupled to the mullions  55  using fasteners (e.g., screws, bolts, etc.). As shown in  FIG. 3 , the clip  115  includes sidewall portions  120  that define a recess  125 . 
       FIGS. 3-5  show that the housing  90  is defined by an extruded body that is formed from a high-impact material that is resistant to breakage. As illustrated in  FIG. 5 , a first axis  130  passes through a middle of the mullion light assembly  85  and divides the light assembly  85  into a left-hand portion and a right-hand portion. The housing  90  extends along a substantial length of each mullion  55 , and is generally symmetrical about the first axis  130 . As illustrated in  FIGS. 3 and 5 , the left-hand portion is substantially a mirror image of the right-hand portion. 
     The housing  90  includes clip members  135  and attachment portions  140 . The clip members  135  extend from sides of the extruded body to couple the housing  90  to the sidewall portions  120 . The attachment portions  140  are disposed on each side of and extend from the extruded body. 
       FIGS. 4 and 5  show that the housing  90  also includes mirror portions  145 , light attachment portions  150 , and extruded members  155 . Each of the mirror portions  145  is disposed adjacent one light attachment portion  150 , and is formed as part of the extruded body. The mirror portion  145  includes a first receiving portion  160 , a second receiving portion  165 , and a central portion  170  that interconnects the first receiving portion  160  and the second receiving portion  165 . Each of the first receiving portions  160  is substantially “U”-shaped, and is disposed on an outer end of the extruded body. The first receiving portion  160  on each end of the extruded body forms a slot  175  that receives a portion of one of the mirrors  105 . The first receiving portions  160  further cooperate with the associated attachment portion  140  to define a channel  180  that receives a respective end of the cover  100 , and that attaches the cover  100  to the housing  90 . Each of the second receiving portions  165  is defined on an end of the mirror portion  145  that is opposite the corresponding first receiving portion  160 . The second receiving portions  165  are further disposed adjacent the light attachment portions  150 . 
     The central portion  170  extends between the first receiving portion  160  and the second receiving portion  165 , and is positioned in close proximity to or adjacent one of the light attachment portions  150 . As shown in  FIG. 5 , the central portions  170  are substantially planar, and are disposed substantially horizontally and perpendicular to the first axis  130 . In other constructions, the central portions  170  may be angularly spaced from the first axis  130  at other angles. 
       FIG. 5  shows that the light attachment portions  150  are formed as a part of the extruded body, and define a stepped recess  185  that is adjacent the central portion  170 . A second axis  190  passes through an upper portion of each of the stepped recesses  185 . The second axis  190  of each of the light attachment portions  150  is angularly spaced from the associated central portion  170 , and defines a first angle α relative to the first axis  130 . In the illustrated construction, the first angle α is about 20 degrees. In other constructions, the first angle α can be larger or smaller than 20 degrees. 
     In some embodiments, the mullion light assembly  85  may include end caps that are attached to the housing to limit accumulation of debris on the mirrors  105  and the LED light sources  110 . Generally, the end caps are removable from the housing  90 . The extruded members  155  define channels  195  that are located on the extruded body adjacent and on an opposite side from the light attachment portions  150 . The end caps are attached to the housing  90  within the channels  195  to cover the ends of the housing  90 . 
       FIG. 6  shows that the cover  100  is attached to the housing  90  to protect the LED light sources  110  from debris or incidental contact. The cover  100  includes obscured portions  200  disposed on ends of the cover  100 , and a substantially clear or transparent portion  205  that extends between the obscured portions  200 . Light from the LED light sources  110  is at least partially diffused or blocked by the obscured portions  200  to obscure visibility of the LED light sources  110  from outside the merchandiser  10 . 
     The mirrors  105  and the LED light sources  110  are generally directed at food product in the product display area  40 .  FIGS. 3 and 5  show that each of the mirrors  105  is attached to the housing  90  within the first and second receiving portions  160 ,  165  and the central portion  170 . In some constructions, the mirrors  105  can be attached to the first and second receiving portions  160 ,  165  and the central portion  170  using an adhesive (e.g., epoxy, glue, etc.). The mirrors  105  are formed from a reflective material (e.g., polished aluminum, polished stainless steel, chrome-plated steel, metallized polymer tape, etc.) to reflect light from the adjacent LED light source  110  into the product display area  40  without loss of luminescence. Generally, the reflectance capacity of the min-ors  105  is above about 70 percent reflectance to reflect a substantial amount of light from the LED light source into the product display area  40 . 
     As shown in  FIG. 4 , each mirror  105  extends a substantial length of the mullion light assembly  85 , and is substantially flat to conform to the substantially planar central portion  170 . In some constructions, the mirrors  105  can have curved mirror surfaces that reflect light into the product display area  40 . 
     Each LED light source  110  is in electrical communication with the case  15  through the mullion  55 .  FIGS. 3-5  show that the LED light sources  110  are attached to the housing  90  within the stepped recesses  185  of the light attachment portions  150 , and include circuit boards  210  that distribute power to and dissipate heat from the LED light sources  110 . The circuit boards  210  are made from conventional printed circuit board material without being metal clad. In some constructions, the circuit boards  210  are formed without an aluminum heat sink. Power is supplied to the LED light sources  110  from a power supply (not shown). 
     The LED light source  110  that is attached to housing  90  on the left of the first axis  130  (as viewed in  FIG. 5 ) is directed in a first direction away from the mullion  55  toward the product display area  40  on the left of the mullion  55 . The LED light source  110  that is attached to the housing  90  on the right of the axis  130  (as viewed in  FIG. 5 ) is directed in a second direction that is symmetrically opposite the first direction (i.e., away from the mullion  55  toward the product display area  40  on the right of the mullion  55 ). Generally, a portion of the light from each LED light source  110  is directed toward the product display area  40 , and another portion of the light is directed toward the corresponding mirror  105 , where the light is reflected and redirected toward the product display area  40 . A small portion of the light from each LED light source  110  may be blocked by the obscured portions  200  such that it does not get directed toward an individual reaching into the product display area  40 . The mirrors  105  and the LED light sources  110  cooperate to define a multi-directional light assembly  85 . 
     As illustrated in  FIG. 7 , each of the LED light sources  110  also includes first LED packages  215  and second LED packages  220 . The first and second LED packages  215 ,  220  are spaced at predetermined distances along the circuit board  210 . For example, the first and second LED packages  215 ,  220  can be defined by an area of about 0.5 inches by 0.5 inches. Each LED package  215 ,  220  can include any number of LEDs. In some constructions, each LED package  215 ,  220  can include three LEDs. In other constructions, each LED package  215 ,  220  may include fewer or more than three LEDs. In still other constructions, the LEDs in each LED package  215 ,  220  can be low current LEDs (e.g., 15 mA). The quantity of the LEDs is determined by the lighting necessary to illuminate the product display area  40 . In constructions where the LED packages  215 ,  220  contain more than a single LED, the LEDs within each LED package  215 ,  220  can be the same or different-colored LEDs. 
     The first LED packages  215  and the second LED packages  220  are arranged in and define an alternating pattern along the length of the circuit board  210 . As viewed in  FIG. 7 , a first LED package  215  is disposed on the left-most end of the circuit board  210 . Moving from left to right on the circuit board  210  (as viewed in  FIG. 7 ), a second LED package  220  is disposed adjacent and to the right of the first LED package  215 . Continuing to the right, another first LED package  215  is disposed adjacent the second LED package  220 . As illustrated in  FIG. 7 , every other LED package along the length of the circuit board is a second LED package  220 . Thus, every other LED package that is not a second LED package  220  is a first LED package  215 . In other words, the alternating arrangement of the LED light sources  110  positions a second LED package  220  between two first LED packages  215 . 
     Other arrangements of the first and second LED packages  215 ,  220  are also possible, and considered herein. For example, the pattern of alternation between the LED packages  215 ,  220  along the length of the circuit board  210  may be: (i) a consistent pattern of equal LED packages (e.g., one by one, two by two, or any other consistent pattern repeating the same number of LED packages  215 ,  220  in series); (ii) a consistent pattern of unequal numbers of LED packages (e.g., one by two, two by three, or any other consistent pattern repeating the same unequal number of LED packages  215 ,  220  in series); and an inconsistent pattern of equal and/or unequal numbers of LED packages. 
     With reference to  FIGS. 5 and 8 , a third axis  225  passes through a center of each LED package  215 ,  220 . The third axis  225  is defined as a zero axis along which light from the LED package  215 ,  220  is generally distributed outward from the housing  90  into the product display area  40 . As illustrated in  FIG. 5 , the third axis  225  is substantially perpendicular to the second axis  190 , and is further angularly spaced from the horizontally disposed central portion  170 . 
     Generally, the first LED packages and the second LED packages can include the same or different LEDs. As illustrated in  FIG. 7 , a lens  230  is coupled to each of the second LED packages  220  to narrow the viewing angle of the second LED packages  220 . In some constructions, the lens  230  is formed from a clear epoxy resin that has a high light transmittance value. In other constructions, the lens  230  can be formed from a hard silicone-based material. In still other constructions, the lens  230  may be formed from a plastic (e.g., polycarbonate). 
       FIG. 8  shows that the first LED packages  215  include a first viewing angle θ, and that the second LED packages  220  include a second viewing angle β. The first viewing angle θ is a wide viewing angle that is defined as the full angle at which the brightness of the first LED package  215  is half of the brightness directed from the center of the LED package  215  (i.e., the brightness along the third axis  225 ). In other words, the brightness within the first viewing angle θ is at least fifty percent of the brightest light, which is directed along the axis  225 , while the brightness of the light outside the first viewing angle θ is less than fifty percent of the brightest light. A fourth axis  235  defines an angle relative to the third axis  225  at which the brightness of the first LED package  215  is one-half of the brightness of the first LED package  215  that is distributed along the third axis  225 . The angle between the third axis  225  and the fourth axis  235  is approximately equal to one-half of the first viewing angle θ. In some constructions, the first viewing angle θ is between about 120 degrees and 140 degrees. In other constructions, the first viewing angle θ can be between about 90 degrees and 180 degrees. Other angles for the first viewing angle θ are also possible, and considered herein. 
     The second viewing angle β is a narrow viewing angle. Similar to the first viewing angle θ, the second viewing angle β is defined as the full angle at which the brightness of the second LED package  220  is half of the brightness directed from the center of the LED package  220  (i.e., the brightness along the third axis). In other words, the brightness within the second viewing angle β is at least fifty percent of the brightest light, which is directed along the axis  225 , while the brightness of the light outside the second viewing angle β is less than fifty percent of the brightest light. A fifth axis  240  defines an angle relative to the third axis  225  at which the brightness of the second LED package  220  is one-half of the brightness of the second LED package  220  that is distributed along the third axis  225 . The angle between the third axis  225  and the fifth axis  240  is approximately equal to one-half of the second viewing angle β. In some constructions, the second viewing angle β is between about 20 degrees and 40 degrees. In other constructions, the second viewing angle β can be between about 5 degrees and 60 degrees. Other angles for the second viewing angle β are also possible, and considered herein. 
     Generally, the relatively narrow or smaller viewing angle β of the second LED packages  220 , as compared to the viewing angle θ, concentrates or focuses the light produced by the LEDs in the second LED packages  220 . The more concentrated light of the second LED packages  220  increases the brightness of the LED packages  220  closer to the third axis  225 . The increased brightness allows the relatively narrow, bright light produced by the second LED packages  220  to be distributed over a relatively long distance. In some constructions, the increased brightness of the second LED packages  220  closer to the third axis  225  creates a substantially pointed source of light. 
       FIG. 9  shows another construction of a mullion light assembly  250  that can be used on the merchandiser  10  adjacent an end of the case  15 . Except as described below, the mullion light assembly  250  is similar to the mullion light assembly  85  described with regard to  FIGS. 2-8 , and common elements are given the same reference numerals. As illustrated in  FIG. 9 , an axis  255  divides the mullion light assembly  250  into a right-hand portion and a left-hand portion. 
     The mullion light assembly  250  includes the mirror  105 , the LED light source  110 , a housing  260 , and a translucent cover  265  that can be attached to the housing  260 . The housing  260  is defined by an extruded body that can be attached to the interior side of each end mullion  55  using a clip  270  that has sidewall portions  275  that define a recess  280  to attach the housing  260  to the mullion  55 . The cover  265  is similar to the cover  100 , and includes an obscured portion  282 , and a transparent portion  283 . 
     The right-hand portion of the mullion light assembly  250  is generally the same as the right-hand portion of the mullion light assembly  85  described with regard to  FIG. 4 . Specifically, the right-hand portion of the housing  260  is substantially similar to the right-hand portion of the housing  90 , except that the extruded members  155  are located in different positions. For example, one extruded member  155  is positioned adjacent and opposite the clip member  135  and the attachment portion  140  on the right-hand portion of the housing  265 . The left-hand portion of the housing further defines an attachment portion  285  that attaches the cover  265  to the housing  260 . The other extruded member  155  is located adjacent and opposite the attachment portion  285  on the left-hand portion. The extruded members  155  can be located anywhere on the housing  260  as long as end caps of the mullion light assembly  250  can be attached to the ends of the housing  260 . 
     The mirror  105  is attached to the housing  260  within the first and second receiving portions  160 ,  165 , and is only located on one side of the housing  260  due to the mullion light assembly  250  being located on the end of the case  15 . The LED light source  110  is attached to the housing  260  within the stepped recess  185  of the light attachment portion  150 , and a portion of the light from the LED light source  110  is aimed directly at the product display area  40 . Another portion of the light from the LED light source  110  is directed at the mirror, where light is reflected into the product display area  40 . 
     In operation, the opposed, multi-directional mullion light assembly  85  uniformly illuminates the product display area  40  while being substantially hidden from view. A first portion of the light directed from the LED light source  110  that is coupled to the housing  90  within the left-hand stepped recess  185  directly illuminates the product display area  40  to the left of the mullion  55 . A second portion of the light directed from this LED light source  110  is reflected by the mirror  105  in a direction that is also generally toward the product display area  40  to the left of the mullion  55 . Similarly, a first portion of light directed from the LED light source  110  that is coupled to the right-hand stepped recess  185  directly illuminates the product display area  40  to the right of the mullion  55 . A second portion of light directed from this LED light source  110  is reflected by the mirror  105  in a direction that is also generally toward the product display area  40  to the right of the mullion  55 . 
     The first LED packages  215  direct light substantially uniformly over the first viewing angle θ toward the shelves  45  so that food product on the shelves  45  can be generally illuminated. The first viewing angle θ of the first LED packages  215  provides substantial illumination of food product that is located adjacent and behind the mullions  55 . The first viewing angle θ further allows the first LED packages  215  to direct at least partially diffuse light over a relatively wide viewing angle to uniformly illuminate food product. In other words, the projection of the light from the first LED packages  215  is generally wide and over a relatively short distance. 
     The second LED packages  220  direct light substantially toward food product on the shelves  45  over the second viewing angle β. Generally, the relatively narrow viewing angle of the second LED packages  220  focus the light toward the shelves to illuminate food product that is located adjacent a center of the shelves  45  between the mullions  55 . The second LED packages  220  generally distribute or direct light at food product on the shelves  45  as substantially pointed sources of light when compared to the relatively diffuse light distributed by the first LED packages  215 . In other words, the projection of the light from the second LED packages  220  is generally narrow and over a relatively long distance. 
     The alternating arrangement of the first LED packages  215  and the second LED packages  220  substantially uniformly illuminates the product display area  40 . By alternating the LED packages  215 ,  220 , food product in the refrigerated merchandiser  10  can be effectively illuminated without taking up a large amount of space in the product display area  40 . The more diffuse, wide viewing angle source of light via the first LED packages  215  cooperate with the more direct, narrow viewing angle source of light via the second LED packages  220  to illuminate a the product display area. 
     The mullion light assemblies  85 ,  250  can be used together or separately with other light assemblies (not shown) in the merchandiser  10  to illuminate the product display area  40 . Use of low current LED packages  215 ,  220  in each mullion light assembly  85 ,  250  provides substantial energy savings. Generally, the overall power required to illuminate and to refrigerate the case  15  using the LED light sources  110  is lower than the power required by cases that use fluorescent light sources. The low current LED light assemblies  85 ,  250  also can be used to replace existing fluorescent of existing merchandisers to provide similar illumination of the product display area  40  via more economical means. 
     Various features and advantages of the invention are set forth in the following claims.