Patent Publication Number: US-9423096-B2

Title: LED lighting apparatus

Description:
RELATED APPLICATION 
     This application is a continuation-in-part of currently pending U.S. application Ser. No. 12/173,721, filed on Jul. 15, 2008, which is based in part on U.S. Provisional Application Ser. No. 61/055,958, filed May 23, 2008. This application is also based in part on U.S. Provisional Application Ser. No. 61/536,560, filed Sep. 19, 2011. The entire contents of each of application Ser. Nos. 12/173,721, 61/055,958 and 61/536,560 are incorporated herein by reference. 
    
    
     FIELD OF THE INVENTION 
     The invention relates generally to the field of lighting systems and, more particularly, to apparatus for utilizing LED light sources for illuminating areas with a predefined pattern of light intensity. The present invention also relates to fixtures which utilize LED light sources in retrofitting old fixtures which previously used other non-LED types of light sources such as high-intensity discharge (HID) lamps. 
     BACKGROUND OF THE INVENTION 
     LEDs (light-emitting diodes) provide light sources which are energy efficient, and advances in LED technology provide even greater such efficiencies over time. Some typical applications for lighting systems are roadway and parking lot lighting in which there are performance requirements such as the requirement that light be uniformly distributed over areas which are to be lighted while the neighboring regions are to be substantially free of light spillage. 
     High-luminance light fixtures using LEDs as light source for outdoor applications present particularly challenging problems. High costs due to high complexity becomes a particularly difficult problem when high luminance, reliability, and durability are essential to product success. 
     Dealing with heat dissipation requirements is still another problem area for high-luminance LED light fixtures. Heat dissipation is difficult in part because high-luminance LED light fixtures typically have many LEDs. Complex structures for LED mounting and heat dissipation have sometimes been deemed necessary, and all of this adds to complexity and cost. 
     In applications such as retrofitting old HID fixtures and other fixtures with LED light sources, especially decorative luminaries that have a look of a particular architectural style such as “acorn” or “tear drop” light fixtures, it is highly desirable to maintain the overall look of the fixture and old-style appearance of illumination. 
     SUMMARY OF THE INVENTION 
     The present invention provides an improved retrofit LED lighting fixture which may include LED lensing providing direction of a majority of light from a light emitter toward a preferential side. The emitter may include a single light-emitting diode (LED) or a plurality of LEDs. Each emitter, regardless of the number of LEDs, has an axis. Such emitters may include an LED package which has a primary lens over the LED(s). In such embodiments, the inventive lens is a secondary lens placed over the primary lens(es). 
     One embodiments of the lens according to the present invention has an emitter-adjacent base end defining a base plane and forming a light-receiving opening, a refracting inner surface which extends from the base end, a lateral surface positioned radially around the inner surface, and an output surface positioned to receive light from the inner end surface and from the lateral surface such that light exits the lens predominantly in the preferential direction. 
     In certain embodiments, the light-receiving opening is elongate across a preferential direction and is adapted to receive light from a group of light emitters aligned along the opening. 
     The refracting inner surface forms a void which may also be elongate across the preferential direction. The void may be formed with a racetrack-shaped inner surrounding surface substantially orthogonal to the base plane and a substantially planar elongate inner end surface configured to direct light from the group of light emitters in the preferential direction. 
     In certain embodiments, the lateral surface is positioned for receiving light refracted by the racetrack-shaped inner surrounding surface for directing received light predominantly in the preferential direction. 
     In some embodiments, the lateral surface includes opposed preferential and non-preferential surface portions adjoined by opposed curved portions. In such embodiments, the non-preferential surface portion is at an angle to the base plane which is greater than an angle of the preferential surface portion to the base plane. 
     Another aspect of the present invention is an LED lighting apparatus comprising a plurality of light emitters each having an emitter axis and a plurality of lenses each positioned over a corresponding light emitter. Each lens is configured for directing light from the corresponding light emitter in a preferential-side off-axial direction with respect to the respective emitter axis. In such embodiments, each lens includes an emitter-adjacent base end forming an opening around the emitter axis and an inner surface extending from the opening. The inner surface defines a void terminating with an end surface which is configured to direct light from the emitter toward the preferential side. The end surface may have a substantially planar portion and may extend from the preferential side away from the base end and across from the preferential side. Each lens also includes a lateral surface radially beyond the void and configured for directing light received from the inner surface toward the preferential side. An output-end surface is positioned to receive light from the inner surface and from the lateral surface. Such light from the emitter exits the output-end surface predominantly toward the preferential side. 
     In certain embodiments, the lateral surface of each lens extends from the base end to terminate proximal to the output-end surface at distances from the emitter axis which are greater on the preferential side than on the non-preferential side. 
     Another aspect of this invention may be useful for retrofit LED light fixtures. Such embodiments of the invention include a plurality of LED emitters and utilize an LED lensing configured to imitate the appearance of a single-light source such as an HID or other light bulb. In this aspect of the invention, improved LED lensing for an LED array facilitates achievement of the appearance of a single-light source, such as an HID or other light bulb. In some of such embodiments, the LED lensing is a unitary lens comprising a plurality of lens members aligned substantially along a preferential/non-preferential line, each lens member being elongate across the preferential/non-preferential line with all elongate lens members being in substantially the same orientation. 
     The term “preferential/non-preferential line,” as used herein, means a line that extends through opposed preferential-side and non-preferential-side end points of the unitary lens. When the unitary lens is utilized in retrofit LED fixtures such as those referred to as “acorn” post-top light fixtures or “tear drop” fixtures, the preferential/non-preferential line would be substantially vertical with the preferential-side end point being at the bottom of the unitary LED lens. In light fixtures of this kind, LED light would be directed primarily outwardly and downwardly to increase illumination of ground areas along which these light fixtures are installed and to minimize wasteful uplight. 
     Some embodiments of such lensing include an emitter-adjacent base end defining a base plane and forming a light-receiving opening which is elongate across the preferential/non-preferential line and is adapted to receive light from a group of light emitters aligned along the opening. A refracting inner surface forms a void which is elongate across the preferential/non-preferential line and has a racetrack-shaped surrounding surface extending from the base end substantially orthogonally to the base plane to terminate at a substantially planar elongate end surface configured to direct light from the emitters toward the preferential side. A lateral surface is positioned for receiving light refracted by the racetrack-shaped inner surrounding surface and has opposed preferential and non-preferential surface portions, the non-preferential portion being at an angle to the base plane which is greater than the angle of the preferential portion to the base plane. An output surface is positioned to receive light from the inner end surface and from the lateral surface such that light exits the lens member predominantly toward the preferential side, whereby light exits the unitary lens predominantly toward the preferential side. 
     In certain embodiments, the unitary lens has a substantially flat outer face substantially parallel to the base plane. The aligned elongate lens members may be positioned with no more than a minimal gap therebetween. In such embodiments, the aligned elongate lens members are positioned such that the unitary lens has substantially continuous light emission across the group of aligned elongate lens members to form a substantially uninterrupted light field to an observer facing the unitary lens. 
     The term “minimal gap,” as used herein, means the shortest distance between the lens members along the preferential/non-preferential line, such distance being no greater than about one fifth of a greatest lens-member dimension along the preferential/non-preferential line. The minimal gap may range from about five millimeters in some embodiments with a smaller greatest lens-member dimension along the preferential/non-preferential line to about one millimeter in some other embodiments. In yet other embodiments, there may be substantially no gap between the lens members which have an outermost edge contacting the outermost edge of the adjacent lens member. 
     A certain aspect of the present invention involves an LED lighting apparatus which has a plurality of LED light sources spaced along an elongate mounting board, each LED light source including a group of LED emitters aligned substantially perpendicular to the mounting-board length. 
     Such LED apparatus includes a plurality of lens members in a line adjacent to one another and each positioned over a corresponding LED light source. Each lens member is elongate in a direction substantially perpendicular to the line and directing light from its corresponding LED light source such that light from the plurality of LED light sources emanates substantially uniformly across the width and along the line of the lens members, thereby generating a substantially uniform luminance from the plurality of lens members. 
     In certain embodiments of the inventive LED lighting apparatus, the mounting board is substantially planar and the plurality of LED light sources have respective emission axes which are substantially parallel to one another and are substantially perpendicular to the mounting board. In some of such embodiments, the lens members direct light from the LED light sources in a primarily off-axial direction. 
     In some of such embodiments of the LED lighting apparatus, the mounting-board length extends between opposite preferential and non-preferential sides; and the lens members direct light from the LED light sources primarily toward the preferential side. 
     Each lens member may have a lens portion and a flange thereabout. In certain embodiments, the flange portions of the plurality of lens members are molded together forming a unified flange portion with the lens portions extending therefrom. 
     Each lens portion may include an emitter-adjacent base end forming an opening around a corresponding emission axis. An inner surface extends from the opening and defines a void terminating with an end surface. In certain embodiments, the end surface extends from the preferential side away from the base end toward the non-preferential side which is across from the preferential side thereby directing light from the corresponding LED light source toward the preferential side. A total internal reflection (TIR) surface is positioned radially beyond the void and directs light received from the inner surface toward the preferential side. An outer output surface receives light from the inner end surface and the TIR surface, such light exiting the output surface predominantly toward the preferential side. 
     The lens-portion opening may be elongate in the direction substantially perpendicular to the line of the lens members. The inner surface may include a surrounding lateral surface extending from the opening to the end surface substantially orthogonally to the base plane. The end surface may be substantially planar and elongate in the direction substantially perpendicular to the line of the lens members. 
     In some embodiments, the TIR surface extends from the emitter-adjacent base end to a racetrack-shaped edge distal from the base plane. In some embodiments, the distal edge has a substantially-straight edge portion on the preferential side. 
     The outer output surface is substantially planar. In some embodiments, the mounting board is substantially planar. In such embodiments, the outer output surface is substantially parallel to the mounting board. In certain versions of the LED lighting apparatus, the flange portion of each of the lens members has an outer surface coplanar with the outer output surface of the corresponding lens member. In some of such versions, the plurality of lens members are parts of a single lens piece with the flange portions of the plurality of lens members being molded together forming a unified flange portion of the single lens piece. Such single lens piece has an outer wall which includes the outer output surfaces and the unified flange portion. 
     In some embodiments, each LED light source includes at least one primary lens. In such embodiments, the corresponding lens member is a secondary lens placed over the at least one primary lens. Each LED emitter may be an LED package having a primary lens over at least one LED. 
     In descriptions of this invention, including in the claims below, the terms “comprising,” “including” and “having” (each in their various forms) and the term “with” are each to be understood as being open-ended, rather than limiting, terms. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view showing an inventive LED configuration inside an old style globe-type lens for an “acorn” fixture. 
         FIG. 2  is a perspective view of an inventive LED arrangement which includes the LED configuration of  FIG. 1 . 
         FIG. 3  is a perspective view of the inventive LED arrangement as in  FIG. 2  and including an LED heat sink positioned atop thereof and an LED driver secured below. 
         FIG. 4  is a side view of the LED arrangement of  FIG. 3  positioned inside the “acorn” globe lens. 
         FIG. 5  is a perspective view showing a luminance view of the retrofit LED light fixture incorporating the LED arrangement according to the present invention. 
         FIG. 6  is a side view of an embodiment of the inventive LED lens. 
         FIG. 7  is a perspective view of an exemplary embodiment an inventive unitary lens. 
         FIG. 8  is a perspective view from above of the LED arrangement of  FIG. 2  with an intermediate refractor positioned over the unitary lens. 
         FIG. 9  is another perspective view from above showing just the LED-supporting sleeve positioned within the intermediate refractor. 
         FIG. 10  is a top view of the 3-dimensional light distribution of the LED arrangement of  FIGS. 2 and 3 . 
         FIG. 11  is a top view of the 3-dimensional light distribution of a single LED arrangement which forms a ⅓ of the light distribution shown in  FIG. 10 . 
         FIG. 12  is a polar plot of the inventive assembled “acorn” retrofit LED light fixture. 
         FIG. 13  is an iso plot of the inventive assembled “acorn” retrofit LED light fixture. 
         FIG. 14  is a top view of the 3-dimensional light distribution of the LED arrangement of  FIGS. 2 and 3  inside an assembled “acorn” retrofit LED light fixture. 
         FIG. 15  is a side view of the 3-dimensional light distribution shown in  FIG. 14 . 
         FIG. 16  is a top perspective view of the LED arrangement as in  FIG. 3 . 
         FIG. 17  is a bottom perspective view of the LED arrangement as in  FIG. 3 . 
         FIG. 18  is a side view opposite to the side view shown in  FIG. 4 . 
         FIGS. 19-25  show assembly of the inventive LED arrangement. 
         FIG. 26  is a top isoview of a single LED arrangement shown in  FIG. 11 . 
         FIG. 27  is a side isoview of the single LED arrangement shown in  FIG. 26 . 
         FIG. 28  is a top view of the 3-dimensional light distribution of the LED arrangement of  FIGS. 2 and 3 . 
         FIG. 29  is a side view of an “acorn” light fixture retrofitted with an LED arrangement according to the present invention. 
         FIG. 30  is a horizontal cross-section view of the LED arrangement of  FIG. 16  with a ray trace of an embodiment of the elongate lens according to the present invention. 
         FIG. 31  is a top view of the inventive LED arrangement and showing a side view of an embodiment of an elongate lens according to the present invention. 
         FIG. 32  is a schematic side ray trace of the lens according to the present invention. 
         FIG. 33  is an enlarged fragmentary cross-sectional view with a ray trace of an embodiment of the LED lighting apparatus according to the present invention. 
         FIG. 34  is a further enlarged fragmentary cross-sectional view of a version of the embodiment of  FIG. 33 . 
         FIG. 35  is a schematic top ray trace of an embodiment of the lens according to the present invention. 
         FIG. 36  is a front iso view showing preferential light distribution with minimized up light. 
         FIG. 37  is a 3-dimensional iso view showing preferential light distribution with minimized up light. 
         FIG. 38  is a cross-sectional view of the LED arrangement shown in  FIG. 31 . 
         FIG. 39  is a preferential-side front perspective view of one embodiment of a single lens piece according to this invention. 
         FIG. 40  is a back perspective view of the single lens piece of  FIG. 39 . 
         FIG. 41  is a front perspective view of the single lens piece of  FIG. 39  shown opaque. 
         FIG. 42  is a back perspective view of the single lens piece as in  FIG. 41 . 
         FIG. 43  is a front elevation of the single lens piece of  FIG. 39 . 
         FIG. 44  is a back elevation of the single lens piece of  FIG. 39 . 
         FIG. 45  is a lateral view of the single lens piece of  FIG. 39 . 
         FIG. 46  is a side view of the single lens piece of  FIG. 39 . 
         FIG. 47  is a cross-sectional view of the single lens piece along a preferential/non-preferential line. 
         FIG. 48  is a side cross-sectional view of the single lens piece taken across preferential/non-preferential line. 
         FIG. 49  is a front elevation of the single lens piece of  FIG. 39  shown opaque. 
         FIG. 50  is a back elevation of the single lens piece as in  FIG. 49 . 
         FIG. 51  is a lateral view of the single lens piece as shown in  FIG. 49 . 
         FIG. 52  is a side view of the single lens piece as shown in  FIG. 49 . 
         FIG. 53  is a cross-sectional view of the single lens piece, as shown in  FIG. 49 , taken along a preferential/non-preferential line. 
         FIG. 54  is a side cross-sectional view of the single lens piece, as shown in  FIG. 49 , taken across preferential/non-preferential line. 
         FIG. 55  is an enlarged perspective of an example of an LED package which has a single LED on a submount with a hemispheric primary lens overmolded over the LED. 
         FIG. 56  is an enlarged side view of the LED package of  FIG. 55 . 
         FIG. 57  is an enlarged top view of the LED package of  FIG. 55 . 
         FIG. 58  is an enlarged top view of another exemplary LED package including an array of four LEDs on a submount and a hemispheric primary lens overmolded over the LED array such that the axis of the primary lens is offset from the axis of the LED array. 
         FIG. 59  is an enlarged perspective view of yet another example of an LED package including an array of eight LEDs on a submount and an asymmetric primary lens overmolded over the LED array. 
         FIG. 60  is an enlarged perspective view of another example of an LED package and including an array of forty-eight LEDs on a submount and an asymmetric primary lens overmolded over the LED array. 
     
    
    
     DETAILED DESCRIPTION OF ILLUSTRATED EMBODIMENTS 
     The present invention illustrated in  FIGS. 1-60  provides an improved LED lensing  10  that may be used for retrofit LED lighting fixture  50 . Illustrated embodiments of lensing  10  provide direction of a majority of light from a light source  60  toward a preferential side  11 . An example of light source  60  is seen in  FIGS. 22-24 and 34 . Each LED light source  60  is shown to have a pair of LED emitters  61  each having an axis  62  seen in  FIG. 33 . Each illustrated LED emitter  61  is an LED package  63  having a primary lens  64  over at least one LED  65 . 
       FIGS. 55-60  show examples of LED emitters that may be used with the present invention.  FIGS. 55-57  show LED package  63 A with single LED  65  on a submount  66  and hemispheric primary lens  64 A coaxially overmolded on submount  66  over LED  65 .  FIGS. 59 and 60  illustrate exemplary LED packages  63 B and  63 C each including an array of LEDs on an LED-populated area which has an aspect ratio greater than 1, and primary lens  64  being overmolded on the submount  66  over the LED-populated area. It is seen in  FIG. 60  that the array may include LEDs emitting different-wavelength light of different colors such as including red LEDs along with light green or other colors to achieve natural white light. Light emitters of the type as LED packages  63 B and  63 C are described in detail in application Ser. No. 13/441,558, filed on Apr. 6, 2012, and in application Ser. No. 13/441,620, filed on Apr. 6, 2012. Contents of both applications are incorporated herein by reference in their entirety. 
       FIGS. 58-60  illustrate versions of LED light emitter  61  configured to refract LED-emitted light toward the preferential side. In each of these LED packages, each LED array defines emitter axis  62 .  FIGS. 59 and 60  illustrate primary lens configured to refract LED-emitted light toward preferential side  11 .  FIG. 58  shows a hemispheric primary lens  64  having a centerline  67  offset from emitter axis  61 . It should be understood that for higher efficiency LED emitter  61  may include a primary lens having both its centerline offset from the emitter axis and also being shaped for refraction of LED-emitted light toward preferential side  11 . In  FIGS. 59 and 60 , primary lens  64  is shown asymmetric. 
       FIGS. 24, 30, 33, 34 and 38  best illustrate LED lighting apparatus  100  which has a plurality of LED light sources  60  spaced along an elongate mounting board  12 , each LED light source  60  including a group of LED emitters  61  aligned substantially perpendicular to the mounting-board length  13 . 
       FIGS. 2 and 24  illustrate LED apparatus  100  which includes a plurality of secondary lens members  20  in a line along a preferential/non-preferential line  2 , lenses  20  being adjacent to one another and each positioned over primary lens(es)  64  of the corresponding LED light source  60 . As best seen in  FIG. 2 , each lens member  20  is elongate in a direction substantially perpendicular to line  2 . FIGS.  5  and  33  best illustrate lens members  20  directing light from its corresponding LED light source  60  such that light from the plurality of LED light sources  60  emanates substantially uniformly across the width of the lens members and along line  2 , thereby generating a substantially uniform luminance from the plurality of lens members  20 . 
       FIGS. 22-24  show mounting board  12  substantially planar and  FIG. 33  illustrates the plurality of LED light sources  60  having respective emission axes  61  which are substantially parallel to one another and are substantially perpendicular to the mounting board  12 .  FIGS. 22-24  further show mounting-board length  13  extending between preferential side  11  and an opposed non-preferential side  14 .  FIG. 33  further shows lens members  20  directing light from LED light sources  60  in a primarily off-axial direction and primarily toward preferential side  11 . 
       FIG. 44  shows each lens member  20  having a lens portion  21  and a flange portion  22  thereabout.  FIGS. 2, 33 and 39-54  illustrate flange portions  22  of the plurality of lens members  20  molded together forming a unified flange portion  220  with lens portions  22  extending therefrom. 
       FIGS. 34, 45-48, 53 and 54  show each lens portion  21  including an emitter-adjacent base end  24  which defines a base plane  25  and forms an opening  26  around a corresponding emission axis  61 . These FIGURES further show an inner surface  30  extending from opening  26  and defining a void  27  terminating with an end surface  31 .  FIGS. 34 and 54  best illustrate end surface  31  extending from preferential side  11  away from base end  24  toward non-preferential side  14  which is across from preferential side  11  such that end surface  31  directs light from the corresponding LED light source  60  toward preferential side  11 , as seen in  FIG. 33 .  FIG. 54  shows end surface  31  extending at a 25° angle with respect to base plane  25 . 
       FIGS. 34, 39, 48, 53 and 54  also show inner surface  30  including a surrounding lateral surface  32  extending from opening  26  to end surface  31  substantially orthogonally to base plane  25 . As seen in  FIG. 54 , the inner surrounding surface  32  may have a slight inward angle of about 5° toward emitter axis  62  from being fully orthogonal with respect to base plane  25 . 
       FIGS. 34, 38-40, 42-48 and 54  further best show a total internal reflection (TIR) surface  40  (also referred to herein as a lateral surface) positioned radially beyond void  27 .  FIGS. 30 and 33  show TIR surface  40  receiving light from inner surface  30 .  FIG. 33  further shows TIR surface  40  directing such light toward preferential side  11 .  FIGS. 48 and 54  show lateral surface  40  having a base-adjacent region  46  which extends from base  24  substantially orthogonally with a slight outward angle of about 5° away from emitter axis  61  from being fully orthogonal with respect to base plane  25 , as seen in  FIG. 54 . 
       FIGS. 40 and 42  show lateral surface  40  including opposed preferential and non-preferential surface portions  43  and  44  adjoined by opposed curved portions  45 .  FIGS. 48 and 54  show opposed preferential and non-preferential surface portions  43  and  44  and curved portions  45  extending outwardly from base-adjacent region  46  to distal edge  41 .  FIGS. 33, 34, 47 and 54  illustrate non-preferential surface portion  44  being at an angle to base plane  25  which is greater than an angle of preferential surface portion  43  to the base plane  25 . 
     It is also seen in  FIGS. 30 and 33  that an outer output surface  28  receives light from inner end surface  31  and from TIR surface  40 . Such light exits output surface  28  predominantly toward preferential side  11 . 
       FIGS. 40-44, 42-44 and 48  best illustrate lens-portion opening  26  being elongate in the direction substantially perpendicular to line  2  of lens members  20  and being adapted to receive light from a group of light emitters  61  aligned along opening  26 .  FIGS. 34, 53 and 54  best show end surface  31  being substantially planar and elongate in the direction substantially perpendicular to line  2  and surrounding surface  32  having a racetrack shape. 
     Refracting inner surface  30  forms void  27  which is also shown elongate across a preferential direction. Void  27  is shown formed with racetrack-shaped inner surrounding surface  32  substantially orthogonal to base plane  25  and substantially planar elongate inner end surface  31  configured to direct light from the group of light emitters  61  in the preferential direction. Lateral surface  40  is shown positioned for receiving light refracted by racetrack-shaped inner surrounding surface  32  for directing received light predominantly in the preferential direction. 
       FIGS. 39, 40 and 42-44  illustrate TIR surface  40  extending from emitter-adjacent base end  24  to racetrack-shaped edge  41  distal from base plane  25 .  FIGS. 44 and 50  show distal edge  41  having a substantially-straight edge portion  42  on non-preferential side  14 . 
       FIGS. 47 and 48  best show outer output surface  28  being substantially planar.  FIGS. 30, 31 and 38  best show outer output surface  28  being substantially parallel to substantially-planar mounting board  12 .  FIGS. 45-48 and 53 and 54  illustrate flange portions  22  of each of lens members  20  having an outer surface  29  coplanar with outer output surface  28  of the corresponding lens member  20 .  FIGS. 39-54  illustrate the plurality of lens members  20  being parts of a single lens piece  200  with flange portions  22  of the plurality of lens members  20  being molded together forming unified flange portion  220  of single lens piece  200 .  FIGS. 48 and 54  further illustrate single lens piece  200  having an outer wall  23  which includes outer output surfaces  28  and unified flange portion  220 . Single lens piece  200 , also referred to herein as a unitary lens, has a substantially flat outer face  230  substantially parallel to base plane  25 . 
       FIG. 48  shows lateral portions  17  extending laterally from flange portions  22  along curves which are parts of a circular cylinder with an axis of revolution being parallel to preferential/non-preferential line  2 . Flange portions  22  of each lens member  22  and unified flange portion  220  of single lens piece  200  each have an inner face  35  extending from TIR surface  40 . In some embodiments, inner face  35  may include matte finish to diffuse light which escapes TIR surface and to provide further “glow” effect further enhancing the substantially uniform luminance. 
       FIGS. 2, 7, 33, 39, 40, 42-45, 47, 50 and 54  show aligned elongate lens members  20  positioned with a minimal gap  15  therebetween such that unitary lens  200  has substantially continuous light emission across the group of aligned elongate lens members  20  to form a substantially uninterrupted light field to an observer facing unitary lens, as illustrated in  FIGS. 5 and 33 .  FIGS. 2 and 7  show the minimal gap being about one fifth of a greatest lens-member dimension along preferential/non-preferential line  2 .  FIGS. 33, 39, 40, 42-45, 47, 50 and 54  illustrate substantially no gap between lens members  20  which have an outermost edge  16  contacting outermost edge  16  of adjacent lens member  20 . 
     Another aspect of this invention may be useful for retrofit LED light fixtures  50 , which by using a plurality of LED emitters and utilizing LED lensing  10 , substantially imitate appearance of a single light source such as an HID light bulb, as shown in  FIG. 5 . 
       FIGS. 1 and 29  illustrate an LED arrangement  51  which includes apparatus  100  positioned inside an old style globe-type lens  53  for an “acorn” fixture.  FIGS. 2, 3, 8 and 9  show that LED arrangement  51  includes three LED-array modules  52  positioned with respect to each other to form a substantially closed shape which imitates a single non-LED light source such as an HID light bulb. As seen in  FIGS. 1, 4 and 18 , LED arrangement  51  is in substantially same position within globe lens  53  as would previously be taken by a non-LED light source. Schematic light distribution of “acorn” retrofit LED light fixture including LED arrangement  51  is illustrated in  FIGS. 10-14 and 28 . 
       FIG. 2  further illustrates LED arrangement  51  which includes an LED-supporting sleeve  54  secured to a mounting post  55  which is inserted inside an existing light socket.  FIGS. 8 and 31  best show LED-supporting sleeve  54  having three substantially planar sides  540  each supporting one of LED-array modules  52 .  FIG. 2  further shows unitary lens  200  positioned over each LED-array module  52 .  FIGS. 22-24  illustrate examples of LED array module  52  having five pairs of LEDs on mounting board  12 . Each LED-array module  52  is secured to one side of LED-supporting sleeve  54  with a permanent heat-conductive adhesive and screws which provide preliminary alignment of LED module with preferential-non-preferential line  2 . Different-power LEDs (as shown in  FIG. 23 ) may be used for various light intensity, as may be desired in various fixture applications.  FIGS. 26 and 27  show isoviews of a single LED arrangement  51 . 
       FIG. 3  shows LED arrangement  51  also including an LED heat sink  56  positioned atop LED-supporting sleeve  54  to facilitate heat dissipation from LEDs  61  through LED-supporting sleeve  54 .  FIGS. 3, 16 and 17  also show an LED driver  57  secured at a lower end of mounting post  55 .  FIGS. 19-25  show assembly of LED arrangement  51 . 
       FIGS. 8 and 9  show one version of LED arrangement  51  including an intermediate refractor  58  positioned over unitary lenses  200  to further blend emitted light for enhancement of a single-light source appearance. Intermediate refractor  58  is particularly useful when outer globe lens  53  is substantially transparent with little or no refractive surface texturing. 
     While the principles of this invention have been described in connection with specific embodiments, it should be understood clearly that these descriptions are made only by way of example and are not intended to limit the scope of the invention.