Patent Publication Number: US-2013235570-A1

Title: Light emitting device with two linear light emitting sections

Description:
BACKGROUND 
     The subject matter disclosed herein generally relates to light emitting devices such as light fixtures, light bulbs, replacement light bulbs, devices comprising light emitting diodes, and their components and method of manufacture. Light emitting devices are needed which are thinner, lighter weight, replaceable, cheaper to manufacture, scalable to large sizes, and have replaceable components. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a bottom view of an embodiment of a light emitting device in the form of a U-shaped LED tube comprising an arcuate light emitting region positioned between two linear light emitting regions. 
         FIG. 2  is a bottom view of a portion of the linear light emitting region of the light emitting device of  FIG. 1 . 
         FIG. 3  is a cross-sectional view of the light emitting device of  FIG. 1  with the light transmitting cover unattached. 
         FIG. 4  is a cross sectional view of the light emitting device of  FIG. 1  with the light transmitting cover attached. 
         FIG. 5  is a perspective view of an embodiment of a secure and removable connector means for connecting a first plurality of leads for a light emitting device. 
         FIG. 6  is a bottom view of an embodiment of a light emitting device comprising three linear light emitting regions. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The features and other details of several embodiments will now be more particularly described. It will be understood that particular embodiments described herein are shown by way of illustration and not as limitations. The principal features can be employed in various embodiments without departing from the scope of any particular embodiment. The present inventive subject matter now will be described more fully hereinafter with reference to the accompanying drawings, in which embodiments of the inventive subject matter are shown. However, this inventive subject matter should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the inventive subject matter to those skilled in the art. Like numbers refer to like elements throughout. As used herein the term “and/or” includes any and all combinations of one or more of the associated listed items. 
     The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the inventive subject matter. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. 
     When an element such as a layer, region or substrate is referred to herein as being “on” or extending “onto” another element, it can be directly on or extend directly onto the other element or intervening elements may also be present. In contrast, when an element is referred to herein as being “directly on” or extending “directly onto” another element, there are no intervening elements present. Also, when an element is referred to herein as being “connected” or “coupled” to another element, it can be directly connected or coupled to the other element or intervening elements may be present. In contrast, when an element is referred to herein as being “directly connected” or “directly coupled” to another element, there are no intervening elements present. 
     In addition, a statement that a first element is “on” a second element is synonymous with a statement that the second element is “on” the first element. 
     Although the terms “first”, “second”, etc. may be used herein to describe various elements, components, regions, layers, sections and/or parameters, these elements, components, regions, layers, sections and/or parameters should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or section from another region, layer or section. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the present inventive subject matter. 
     Furthermore, relative terms, such as “lower” or “bottom” and “upper” or “top,” may be used herein to describe one element&#39;s relationship to another element as illustrated in the Figures. Such relative terms are intended to encompass different orientations of the device in addition to the orientation depicted in the Figures. For example, if the device in the Figures is turned over, elements described as being on the “lower” or “bottom” side of other elements would then be oriented on the “upper” or “top” sides of the other elements. The exemplary term “lower”, can therefore, encompass both an orientation of “lower” and “upper,” depending on the particular orientation of the figure. Similarly, if the device in one of the figures is turned over, elements described as “below” or “beneath” other elements would then be oriented “above” the other elements. The exemplary terms “below” or “beneath” can, therefore, encompass both an orientation of above and below. 
     Light Emitting Device 
     In one embodiment, a light emitting device comprises two tubes comprising linear arrays of light emitting diodes physically coupled by a third tube. In one embodiment, the third tube comprises a linear array of light emitting diodes. In another embodiment, the first tube, second tube, and third tube of the light emitting device are positioned to substantially form the shape of a character “U” in a plane perpendicular to the optical axis. In another embodiment, an array of light sources disposed on a heat sink or housing substantially in the shape similar to the character “U.” In one embodiment, the light emitting device comprises a curved array of light sources disposed at a pitch such that the light is perceived as a single continuous curve of light by an individual with a visual acuity of 1 arcminute at a distance of 1 meter. In another embodiment, the light sources are an array of Light Emitting Diodes (LEDs) disposed on a circuit board thermally coupled to an aluminum tube heat sink. In one embodiment, a light emitting device comprises a U-shaped array of LEDs disposed on one or more circuit boards wherein the light emitting device is a replacement bulb. In one embodiment, the light emitting device comprises two parallel tube sections operatively coupled to a third tube section oriented orthogonal to the two parallel tube sections. 
     Light Source 
     In one embodiment, a light emitting device comprises an array of two or more light sources. In another embodiment, a curved light emitting device comprises an array of LEDs positioned along a curve and upon one or more circuit boards. In one embodiment, the array of light sources is a curved array with discrete LED packages comprising at least one LED die. In another embodiment, a light emitting device comprises a plurality of light sources within one package disposed to emit light toward a surface for illumination. In one embodiment, the light emitting device comprises at least one selected from the group of: 2, 3, 4, 5, 6, 8, 9, 10, 20, 40, 60, 80, 100, 120, 140, 160, 180, 200, 220, 240, 260, 280, 300, 320, 340, 360, 380, and 400 light emitting diodes. In one embodiment, the dimension, A, of the LED in a linear direction is less than one selected from the group of 10 mm, 8 mm, 6 mm, 5 mm, 4 mm, 3 mm, and 2 mm. 
     Spectral Properties of the Light Source 
     In one embodiment, a light emitting device comprises at least one broadband light source that emits light in a wavelength spectrum larger than 100 nanometers. In another embodiment, a light emitting device comprises at least one narrowband light source that emits light in a narrow bandwidth less than 100 nanometers. In another embodiment, a light emitting device comprises at least one broadband light source that emits light in a wavelength spectrum larger than 100 nanometers or at least one narrowband light source that emits light in a narrow bandwidth less than 100 nanometers. In one embodiment a light emitting device comprises at least one narrowband light source with a peak wavelength within a range selected from the group of 300 nm-350 nm, 350 nm-400 nm, 400 nm-450 nm, 450 nm-500 nm, 500 nm-550 nm, 550 nm-600 nm, 600 nm-650 nm, 650 nm-700 nm, 700 nm-750 nm, 750 nm-800 nm, and 800 nm-1200 nm. The light sources may be chosen to match the spectral qualities of red, green and blue such that collectively when used in a light emitting device, the color may be dialed in to achieve a desired color. In one embodiment, at least one light source is an LED package comprising a red, green, and blue LED capable of emitting light with a white color when each are emitting light. In another embodiment, the LED is a blue or ultraviolet LED combined with a phosphor. In another embodiment, a light emitting device comprises a light source with a first activating energy and a wavelength conversion material which converts a first portion of the first activating energy into a second wavelength different than the first. In another embodiment, the light emitting device comprises at least one wavelength conversion material selected from the group of a fluorophore, phosphor, a fluorescent dye, an inorganic phosphor, photonic bandgap material, a quantum dot material. In another embodiment, the light emitting device comprises white LED light sources. In another embodiment, the light sources comprise LEDs that are at least one selected from the group of: warm white, cool white, neutral white, daylight white, have a correlated color temperature between 2200 K and 2900 K, have a correlated color temperature between 2900 K and 3600 K, have a correlated color temperature between 3600 K and 4500 K, have a correlated color temperature between 4500 K and 4900 K, and have a correlated color temperature between 4900 K and 6600 K. 
     Shape of Light Emitting Device 
     In one embodiment, the shape of the light emitting device is substantially in the shape of the character “U.” In one embodiment, the shape comprises three linear sections, with one section oriented at an angle (90 degrees, for example) to two parallel sections. In one embodiment, the light emitting devices comprises an arcuate light emitting region positioned between two linear light emitting regions. In one embodiment, the total length of the light emitting device is one selected from the group: 20-30, 25-35, 30-40, 35-45, 40-50, 45-55, 50-60, 55-65, 60-70, and 65-75 centimeters in length from the base pins to the outer surface of the arcuate light emitting region. In one embodiment, the ends of the light emitting device comprise medium bi-pin (G13) bases. In another embodiment, the light emitting device comprises miniature T-5 lamp bi-pin bases, medium T-8 lamp bi-pin bases, or medium T-12 lamp bi-pin bases. In one embodiment, the cross-section of the light emitting device is substantially circular. In another embodiment, the diameter of the cross section is substantially 1.5 inch or 1 inch. In one embodiment, the spacing between the linear tubular regions at the base or other region is greater than or equal to about one selected from the group 1.5, 3, and 6 inches. In a further embodiment, the total length of the curved light emitting region of the light emitting device is greater than one selected from the group of 100 mm, 150 mm, 300 mm, 400 mm, 500 mm, 600 mm, 700 mm, 900 mm, 1 meter, 1.2 meters, 1.4 meters, 1.6 meters, 1.8 meters, 2 meters, 2.2 meters, and 2.4 meters. In another embodiment, the total length of the curved light emitting region of the light emitting device is one selected from the group of: between 560 and 600 millimeters, between 1170 and 1300 millimeters, and between 2340 and 2600 millimeters. In one embodiment, the light emitting device comprises first and second linear light emitting tube sections parallel to each other and a third linear light emitting tube section orthogonal to the first and second linear light emitting tube sections. In another embodiment, the light emitting device comprises first and second linear light emitting tube sections parallel to each other and a third non-emitting linear tube section orthogonal to the first and second linear light emitting tube sections. 
     In one embodiment, the light emitting device comprises three linear sections and two couplers that operatively couple two parallel linear sections to a third linear section orthogonal to the first two parallel linear sections. In one embodiment, the coupler comprises two openings oriented 90 degrees to each other into which two linear sections are positioned. In another embodiment, the coupler comprises a coupler arcuate region along at least one side in a plane comprising the two linear sections extending into the coupler. For example, one or more couplers may comprise a 90 degree elbow comprising polyvinyl chloride (PVC). 
     In one embodiment, the first tube, second tube, and third tube of the light emitting device are positioned to substantially form the shape of a character “U” in a plane perpendicular to the optical axis. In another embodiment, the light emitting device may be substantially in the shape of the character “␣” while comprising a support bar (with a smaller dimension or diameter than the tube sections) in a region near the electrical connectors (such as bi-pin base connectors). In one embodiment, the support bar is a linear section physically coupled to the two parallel linear sections that provide increased rigidity and stability for the light emitting device. In one embodiment, the support bar is near an end of the light emitting device opposite the third tube. The support bar may comprise a polymer, metal, ceramic, or combination thereof. 
     Radius of Curvature of Arcuate Region 
     In one embodiment, the radius of curvature of the arcuate region of the light emitting device is selected from the group 20-90, 20-80, 20-30, 40-50, 50-60, 60-70, 70-80, 80-90, 90-100, and 100-110 millimeters. In one embodiment, the radius of curvature of the arcuate region is about 97 millimeters and the length is about 560 millimeters. In one embodiment, the radius of curvature of the arcuate region is greater than 40 millimeters. In one embodiment, the arcuate region comprises light emitting diodes. In another embodiment, one or more couplers comprise one or more arcuate regions. 
     Circuit Board 
     In one embodiment, the LEDs of the light emitting device are disposed upon a single circuit board. In one embodiment, the circuit board is shaped substantially like the character “U”. In another embodiment, the light emitting device comprises a plurality of circuit boards. In another embodiment, the light emitting device comprises a curved circuit board and one or more linear circuit boards. In another embodiment, the light emitting device comprises two curved circuit boards. In another embodiment, the light emitting device comprises three linear circuit boards. 
     Pitch of the Light Sources 
     In one embodiment, the light emitting device comprises an array of LEDs with an average density greater than one selected from the group of: 2, 3, 4, 5, 6, 7, 8, 9, and 10 LEDs per linear inch. In one embodiment, a curved light emitting device comprises a curved array of LEDs with an average pitch, P, disposed parallel to a linear direction of the array of LEDs in the linear light emitting region of the light emitting device. In one embodiment, the pitch, P, is less than one selected from the group of 10 mm, 8 mm, 6 mm, 5 mm, 4 mm, 3 mm, and 2 mm. In one embodiment, within the linear light emitting region, the average ratio of the dimension in the linear direction of the LED to the average spacing between the LEDs in the linear direction is one selected from the group: 0.5-3.0, 0.5-1.0, 0.8-1.0, 1.0-1.2, 1.2-1.4, 1-1.5, 1.0-2.0, and 1.0-3.0. In another embodiment, the average ratio of the dimension in the linear direction of the LED to the average spacing between the LEDs in the linear direction is less than 5. 
     In another embodiment, the average spacing between the LEDs, D, is one selected from the group: 0.1 to 0.5, 0.5 to 1.0, 1.0-1.5, 1.2-1.8, 1.5-2.0, and 1.8-2.2 millimeters. In another embodiment, the average ratio of the dimension of the LED oriented closest to the direction of the arc at the LED to the average spacing between the LEDs along the arc is one selected from the group: 0.5-3.0, 0.5-1.0, 0.8-1.0, 1.0-1.2, 1.2-1.4, 1-1.5, 1.0-2.0, and 1.0-3.0. 
     Orientation of the Light Sources 
     In one embodiment, the light emitting device comprises a curved array of rectangular LEDs with a first dimension in a first direction orthogonal to the optical axis of the light emitted from the LED longer than a second dimension in a second direction orthogonal to the first direction and orthogonal to the optical axis of the light emitted from the LED, wherein the LEDs are positioned with their second dimension substantially parallel to the linear direction of the linear region disposed between the base and the arcuate region and at least one LED within the arcuate region is positioned with its second dimension oriented at an angle greater than zero to the linear direction. In one embodiment, the orientation of two or more LEDs changes along the arcuate light emitting region of the light emitting device. In one embodiment, the arcuate light emitting region comprises an LED oriented orthogonal in a plane orthogonal to the optical axis of the LED to the orientation of an LED in the linear light emitting region. 
     Spatial Uniformity of Light Emitting Region 
     In one embodiment, the light emitting device has a spatial luminance profile with a curved bright region with a substantially uniform luminance along the surface of the light transmitting cover positioned above the linear array of LEDs or the curved array of LEDs. In one embodiment, the luminance uniformity, U, measured at the surface of the light transmitting cover along the linear array section or the curved array section above the array of LEDs, is greater than one selected from the group: 60%, 70%, 80%, 85%, 90%, and 95% with the uniformity, U, defined by the equation: 
     
       
         
           
             U 
             = 
             
               
                 L 
                 min 
               
               
                 L 
                 max 
               
             
           
         
       
     
     where L min  is the average minimum luminance along the light emitting surface and L max  is the average maximum luminance along a surface of the light emitting surface when measured with a 5 mm or greater spot size. In one embodiment, the light transmitting cover is substantially clear and has a haze less than 10%. In another embodiment, the light transmitting cover is diffuse and has a haze (when flattened to a non-arcuate shape by thermoforming and/or pressure and measured according to ASTM D1003) greater than one selected from the group of 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, and 90%. In the haze measurements, when the sample is arcuate, the sample is flattened by thermoforming, pressure, or a combination thereof such that the optical properties do not substantially change in the direction normal to the surface, but the overall shape is substantially flat to be measured according to ASTM D1003 using a BYK Gardner haze meter. In another embodiment, the light transmitting cover comprises a phosphor region disposed to receive blue and/or ultraviolet light and convert a percentage of incident light into light of a different wavelength such that the combination of the blue and/or UV light with the converted light output is substantially white. 
     Power Source 
     In one embodiment, the light emitting device is powered by an electrical signal selected from the group of 12V DC, 12V AC, ˜110-120V AC, ˜220-240V AC, switchable power supply, 28V DC power supply, AC power supply, DC power supply, and 3V DC power supply. In one embodiment, the power is provided by a craft such as an automobile, aircraft, or watercraft. In another embodiment, the power supply is a battery supply, or the light emitting device has a backup battery based power supply. In another embodiment, the light emitting device comprises a solar cell and a battery such that the battery can be charged by exposure to light such as sunlight and energy is stored in the battery for future use. In one embodiment, the light emitting device is a curved LED tube for replacement of a U-shaped fluorescent tube in a fixture and comprises an LED driver disposed within the heat sink tube with an electrical connection to the LEDs and an electrical connection to the electrical connection pins of the light emitting device. 
     Secure and Removable Connector 
     In one embodiment, a light emitting device comprises a aluminum tube heat sink, an array of LEDs disposed on a circuit board and thermally coupled to the aluminum tube heat sink, an LED driver that converts AC electrical power into DC power to drive the LEDs, electrical connection pins, and a secure and removable connector means comprising a female connector, a male connector and a fastener such as, without limitation, a cable tie. In this embodiment, the leads from the electrical connection pins at one or both ends of the tube may be electrically coupled to the LED driver by the removable connector means. Also, in this embodiment, the leads to circuit board comprising the LEDs may be electrically coupled to the LED driver by the removable connector means. In one embodiment, the two leads from the AC power (and the electrical connectors such as pins) are connected to a female electrical connector and the two leads connected to the LED driver are connected to a male electrical connector electrically coupled into the female connector. In this embodiment, the cable tie can be extended around the female and male connector between the two leads from the AC power and between the two leads connected to the LED driver. In this embodiment, by placing the cable tie between the leads on the male and the female connector, the cable tie will not slide off of the two connectors it is holding together. Furthermore, in this embodiment, the cable tie can securely couple the female and male connector together. In addition, by cutting the cable tie, the connectors can be easily separated such that the LED driver can be replaced, for example. In another embodiment, the light emitting device comprises a secure and removable connector means between the LED driver and the power source and the LED driver and the LEDs such that the driver may be easily replaced by cutting the fasteners and separating the connectors. In one embodiment, the fastener is a cable tie (also known as a zip tie and tie wrap). In a further embodiment, the fastener is disposed to physically couple the male and female connectors to form an electrical connection and is one selected from the group of belt hook, rapstrap fastener, metal buckle clip, strap, snap, ring, pin, plastic cable tie, tear-away-tie, and reusable cable tie. In another embodiment, the male and female connectors are one selected from the group of: quick connect terminals, fork connectors, disconnects, fully insulated, partially insulated, locking fork, quick disconnect, and wire terminals. 
     Groove and Extension for Cover Seal 
     In one embodiment, the light emitting device comprises a linear groove in a heat sink or housing element and light transmitting cover with an extension that can slide into or snap into the groove to provide a seal. In one embodiment, an aluminum heat sink tube comprises a groove on opposite sides of the tube and a light transmitting cover comprises an extension disposed on opposite sides such that when the extensions are slid or snapped into the groove, a water or moisture resistant seal is formed between the light transmitting cover and the heat sink. In a further embodiment, a gasket (such as a rubber strip) is disposed within the groove such that the seal between the light transmitting cover and the heat sink has a higher water or moisture resistance. 
     Groove in the Housing or Heat Sink 
     In one embodiment, the groove disposed in the housing of the light emitting device or the tube heat sink of the light emitting device extends substantially along the curved shape of the light emitting area of the light emitting device. In another embodiment, the groove has an opening width, G w , selected from the group of: between 0.5 mm and 10 mm, between 0.5 mm and 5 mm, between 0.5 mm and 2 mm, and between 0.5 mm and 1.5 mm. In another embodiment, the groove has a uniform depth, G d , selected from the group of: between 0.5 mm and 10 mm, between 0.5 mm and 5 mm, between 0.5 mm and 2 mm, and between 0.5 mm and 1.5 mm. In another embodiment, the groove has a non-uniform depth, with the depth on a first side, G d1 , selected from the group of: between 0.5 mm and 10 mm, between 0.5 mm and 5 mm, between 0.5 mm and 2 mm, and between 0.5 mm and 1.5 mm; and the depth on a second side, G d2 , selected from the group of: G d1 +0.5 mm, G d1 +1 mm, G d1 +1.5 mm, G d1 +2 mm, G d1 +2.5 mm, G d1 +3.5 mm, G d1 +4 mm, G d1 +T 1  (where T 1  is the average thickness of the light transmitting cover near the extension), and between G d1 +(0.9×T 1 ) and G d1 +(1.1×T 1 ). In another embodiment, the groove depth is non-uniform in the plane perpendicular to the linear direction of the linear light emitting region, and the light transmitting cover and heat sink form a shape with a cross-section with an outer surface substantially that of a circle. In another embodiment, the light transmitting cover and heat sink form a shape with a cross-section with an outer surface substantially that of a circle except for micro ridges in the section of the heat sink. 
     Extension in Light Transmitting Cover 
     In one embodiment, the extension in the light transmitting cover of the light emitting device has a depth, d, selected from the group of: between 0.5 mm and 10 mm, between 0.5 mm and 5 mm, between 0.5 mm and 2 mm, between 0.5 mm and 1.5 mm, greater than 0.5 mm, and less than 10 millimeters. In another embodiment, the extension in the light transmitting cover of the light emitting device has a height, h, selected from the group of: between 0.5 mm and 10 mm, between 0.5 mm and 5 mm, between 0.5 mm and 2 mm, between 0.5 mm and 1.5 mm, greater than 0.5 mm, and less than 10 millimeters. 
     Waterproof 
     In one embodiment, the light source and electrical components are substantially sealed by at least one of an epoxy, resin, rubber, silicone, or polymer such that the electrical components are waterproof to a depth selected from the group of 5 feet, 10 feet, 20 feet, 30 feet, 50 feet, 100 feet, and 200 feet. In another embodiment, the light emitting device components satisfy the United Laboratories UYMR2 standards for components and fittings intended for use in electric signs and accessories. In another embodiment, the light emitting device continues to operate after a 12 hour continuous salt spray test. In another embodiment, the light emitting device continues to operate after a 24 hour continuous salt spray test. In one embodiment, the light emitting device continues to operate after a 48 hour continuous salt spray test. In one embodiment, the light emitting device continues to operate after a 60 hour salt water soak test. In one embodiment, the light emitting device continues to operate after a 120 hour salt water soak test. In another embodiment, the light emitting device continues to operate after a 240 hour salt water soak test. 
     The following are more detailed descriptions of various embodiments illustrated in the Figures. 
       FIG. 1  is a bottom view of an embodiment of an embodiment of a light emitting device  100  in the form of a U-shaped LED tube comprising an arcuate light emitting region  104  positioned between two linear light emitting regions  103  and a curved array of LEDs  106  positioned below a curved circuit board  102 . The light emitting device  100  comprises two bi-pin bases  101  configured to receive electrical power for the light emitting device  100 . A light transmitting cover  107  is disposed above the curved array of LEDs  106  to transmit the light received from the LEDs  106  out of the light emitting device  100 . The arcuate light emitting region  104  has radius of curvature  108  of R and the linear light emitting regions  103  of the curved array of LEDs  106  extend in a linear direction  105  (y direction) from the bi-pin bases  101 . In the embodiment shown in  FIG. 1 , the LEDs  106  are rotated in the x-y plane in the arcuate light emitting region  104  relative to the linear light emitting region  103 . The light emitting device  100  shown in  FIG. 1  may be used to replace a U-shaped fluorescent bulb in a light fixture. 
       FIG. 2  is a bottom view of a portion of the linear light emitting region  103  of the light emitting device  100  of  FIG. 1  comprising the array of LEDs  106  with a pitch, P, disposed below a circuit board  102 . The LEDs  106  are substantially rectangular and positioned with their shorter dimension, A, parallel to the linear direction  105 . The longer dimension, B, of the LEDs  106  is positioned substantially orthogonal to the linear direction  105 . The spacing, D, between the LEDs  106 , in the embodiment shown in  FIG. 2 , is less than the shorter dimension, A, of the LEDs  106 . 
       FIG. 3  is a cross-sectional view of the light emitting device  100  of  FIG. 1 . An aluminum heat sink tube  302  comprises an LED driver  308  within the interior and the LEDs  106  are disposed below a circuit board  102  that is thermally coupled to the aluminum heat sink tube  302  by a thermally conductive adhesive. The aluminum heat sink tube  302  further comprises two grooves  305  disposed parallel to the linear direction (out of the page) along each side. The grooves  305  are disposed to receive the extensions  306  in the light transmitting cover  107  with a substantially arcuate cross section. The extensions  306  have a lateral length, d, in the x direction and a height, h, in the z direction such that the extensions  306  can be snapped or slid into place in the groove  305 . In the embodiment shown in  FIG. 3 , the grooves  305  further comprise a gasket  301  (optional) to further reduce water penetration into the light emitting device  200  when submersed or exposed to damp conditions. 
       FIG. 4  is a cross sectional view of the light emitting device  100  of  FIG. 1  with the light transmitting cover  107  attached such that the extensions  306  are disposed in the grooves  305 . In this embodiment, the aluminum heat sink tube  302  and the light transmitting cover  303  provide a seal to reduce or prevent water or moisture penetration into the electrical components within the light emitting device  100 . 
       FIG. 5  is a perspective view of an embodiment of a secure and removable connector means  500  for connecting a first plurality of leads ( 501  and  502 ) to a second plurality of leads ( 503  and  504 ) using a male connector  505 , a female connector  506  and a cable tie  507 . The cable tie  507  is fastened between the leads  501  and  502  and between the leads  503  and  504 . The leads  502  and  503  are disposed to provide AC electrical power to the LED driver  308 . In this embodiment, the cable tie  507  securely holds the male connector  505  and female connector  506  together and the cable tie  507  can be cut to allow the LED driver  308  for a light emitting device to be changed or replaced. 
       FIG. 6  is a bottom view of an embodiment of a light emitting device  600  comprising three linear tubes  601 ,  604 , and  608 . The first tube  601  comprises a first light transmitting cover  617  and a first linear array of light emitting diodes  602  with the array oriented in a first direction  603 . The second tube  604  comprises a second light transmitting cover  618  and a second linear array of light emitting diodes  605  with the array oriented in a second direction  606  parallel to the first direction  603 . The third tube  608  comprises a third light transmitting cover  619  and a third linear array of light emitting diodes  609  with the array oriented in a third direction  610  orthogonal to the first direction  603  and the second direction  606 . In the embodiment shown in  FIG. 6 , the tubes  601 ,  604 , and  608  comprise linear arrays of light emitting diodes  602 ,  605 , and  609  that are 1×N arrays where N is the number of light emitting diodes in the array direction. The first tube  601 , the second tube  604 , and the third tube  608  of the light emitting device  600  are positioned to substantially form the shape of a character “U” in a plane (x-y plane) perpendicular to the optical axis (+z axis). 
     The first linear array of light emitting diodes  602  are rectangular in shape with a shorter dimension in the y direction than in the x direction and are positioned with their optical axis parallel to the +z direction (out of the page) such that light from the first linear array of light emitting diodes  602  transmits through the first light transmitting cover  617  and the luminance uniformity at the first light transmitting cover  617  in the first direction  603  is greater than 60%. The second linear array of light emitting diodes  605  are rectangular in shape with a shorter dimension in the y direction than in the x direction and are positioned with their optical axis parallel to the +z direction (out of the page) such that light from the first linear array of light emitting diodes  605  transmits through the second light transmitting cover  618  and the luminance uniformity at the second light transmitting cover  618  in the second direction  606  is greater than 60%. The third linear array of light emitting diodes  609  are rectangular in shape with a shorter dimension in the x direction than in the y direction and are positioned with their optical axis parallel to the +z direction (out of the page) such that light from the third linear array of light emitting diodes  609  transmits through the third light transmitting cover  619  and the luminance uniformity at the third light transmitting cover  619  in the third direction  610  is greater than 60%. 
     The first tube  601  is physically coupled to the third tube  608  by a first 90 degree elbow coupler  615  with an arcuate region  616  in a plane comprising the first tube  601  and the third tube  608 . The second tube  604  is physically coupled to the third tube  608  by a second 90 degree elbow coupler  613  with an arcuate region  614  in a plane comprising the second tube  604  and the third tube  608 . The first tube  601  is physically coupled to the second tube  604  by a support bar  612  in a region near the electrical bi-pin base connectors  611  used to provide electrical power to the light emitting diodes  602 ,  605 , and  609 . In one embodiment, the couplers have substantially straight sides forming a sharp corner in the plane orthogonal to the optical axis of the light emitting diodes. 
     EQUIVALENTS 
     Those skilled in the art will recognize, or be able to ascertain using no more than routine experimentation, numerous equivalents to the specific procedures described herein. Such equivalents are considered to be within the scope of the invention. Various substitutions, alterations, and modifications may be made to the invention without departing from the spirit and scope of the invention. Other aspects, advantages, and modifications are within the scope of the invention. The contents of all references, issued patents, and published patent applications cited throughout this application are hereby incorporated by reference. The appropriate components, processes, and methods of those patents, applications and other documents may be selected for the invention and embodiments thereof. This application is intended to cover any adaptations or variations of the specific embodiments discussed herein. Therefore, it is intended that this disclosure be limited only by the claims and the equivalents thereof. 
     Unless otherwise indicated, all numbers expressing feature sizes, amounts, and physical properties used in the specification and claims are to be understood as being modified by the term “about”. Accordingly, unless indicated to the contrary, the numerical parameters set forth in the foregoing specification and attached claims are approximations that can vary depending upon the desired properties sought to be obtained by those skilled in the art utilizing the teachings disclosed herein. Unless indicated to the contrary, all tests and properties are measured at an ambient temperature of 25 degrees Celsius or the environmental temperature within or near the device when powered on (when indicated) under constant ambient room temperature of 25 degrees Celsius.