Abstract:
A method of making a substantially monolithic lighting device comprising serially connected LEDs and lighting systems including the same. The serially connected LEDs may be comprised in a monolithic device comprising a first LED, a layer of conductive material, and a second LED positioned thereupon. The serially connected LEDs may also be electrically coupled to a plurality of resistors obviating the necessity of an AC/DC power converter when a luminaire containing the serially connected LEDs is connected to an AC power source.

Description:
FIELD OF THE INVENTION 
     The present invention relates to systems and methods for serially-connected lighting devices composed of serially-connected light-emitting diodes (LEDs), methods of making the same, and luminaires that contain the same. 
     BACKGROUND OF THE INVENTION 
     The use of light emitting diodes (LEDs) in lighting devices has been consistently confronted with the challenge of generally non-uniform distribution of light emitted by the LEDs. This problem arises from the nature of how LEDs are fabricated, namely the deposition of semiconducting materials on a substrate that obscures or otherwise prevents the propagation of light therethrough. As such, LEDs have tended to emit light only in a hemisphere generally above the substrate. Moreover, the subsequent attachment of LEDs to an opaque circuit board further prevents light from propagating into the hemisphere generally “below” the LED. Attempts to compensate for this problem have included the positioning of multiple LEDs in varying orientations, reflection/refraction of light emitted by the LEDs, and the like. The solution presented below provides a method for fabricating an LED that has a generally omnidirectional light emission profile, or at least substantially greater than a hemispherical light emission profile. The solution presented below also discloses lighting systems and luminaires comprising such fabricated LEDs. 
     This background information is provided to reveal information believed by the applicant to be of possible relevance to the present invention. No admission is necessarily intended, nor should be construed, that any of the preceding information constitutes prior art against the present invention. 
     SUMMARY OF THE INVENTION 
     With the foregoing in mind, embodiments of the present invention are related to methods of fabricating a lighting device comprising providing a substrate having a surface, forming a first LED on the surface of the substrate, the first LED having a surface, attaching a first layer of conductive material on the surface of the first LED, the conductive material having a surface, forming a second LED on the surface of the conductive material, and removing the substrate. 
     Other embodiments of the invention are related to luminaires comprising first and second terminals connected to an alternating current power source having a period, a first LED light source electrically coupled to each of the first and second terminals, and a second LED light source electrically coupled to each of the first and second terminals. Furthermore, the first LED light source may comprise a color conversion layer having an emission latency. 
     Other embodiments of the invention are related to luminaires comprising a base having an electrical connector configured to couple electrically to a power source, an optic attached to the base so as to define an optical chamber, a first and second support carried by the base and positioned within the optical chamber, and a light source comprising a plurality of serially-connected LEDs. The light source may have a positive terminal coupled electrically to the anode of one LED of the plurality of LEDs and a negative terminal coupled electrically to the cathode of another LED of the plurality of LEDs. The first support may be in electrical communication with each of the electrical connector and the positive terminal. Also, the second support may be in electrical communication with each of the electrical connector and the negative terminal. 
     Other embodiments of the invention are related to lighting systems comprising a first light source having a plurality of serially connected LEDs and a plurality of resistors coupled electrically at one end to a node between a pair of LEDs and at another end to a ground. The first LED of the series may be connected to a triac AC power supply at its anode, and the last LED of the series may be connected to the ground at its cathode. The electrical connection between each pair of LEDs further may comprise a connection to a resistor that is serially connected to the ground. The LEDs may be arranged such the number of LEDs that emit light varies directly with the instantaneous voltage supplied by the AC power supply. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1   a  is a side view of a lighting device die including a first light emitting diode according to an embodiment of the invention. 
         FIG. 1   b  is a side view of the lighting device die of  FIG. 1   a  further including a conductive layer. 
         FIG. 1   c  is a side view of the lighting device die of  FIG. 1   b  further including a second light emitting diode. 
         FIG. 1   d  is a side view of the lighting device die of  FIG. 1   c  wherein the substrate has been removed. 
         FIG. 2  is a perspective view of the lighting device of  FIG. 1   d  further including a plurality of troughs. 
         FIG. 3  is a side view of the lighting device die of  FIG. 1   d  further including a second conductive layer and a third light emitting diode. 
         FIG. 4  is a perspective view of a monolithic lighting device according to an embodiment of the invention. 
         FIG. 5  is a schematic circuit diagram of a lighting device according to an embodiment of the present invention. 
         FIG. 6  is a perspective view of a monolithic lighting device according to an embodiment of the invention. 
         FIG. 7  is a side view of a luminaire according to an embodiment of the present invention. 
         FIG. 8  is a side view of a luminaire according to another embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The present invention will now be described more fully hereinafter with reference to the accompanying drawings, in which preferred embodiments of the invention are shown. This invention may, however, be embodied in many different forms and 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 invention to those skilled in the art. Those of ordinary skill in the art realize that the following descriptions of the embodiments of the present invention are illustrative and are not intended to be limiting in any way. Other embodiments of the present invention will readily suggest themselves to such skilled persons having the benefit of this disclosure. Like numbers refer to like elements throughout. 
     Although the following detailed description contains many specifics for the purposes of illustration, anyone of ordinary skill in the art will appreciate that many variations and alterations to the following details are within the scope of the invention. Accordingly, the following embodiments of the invention are set forth without any loss of generality to, and without imposing limitations upon, the claimed invention. 
     In this detailed description of the present invention, a person skilled in the art should note that directional terms, such as “above,” “below,” “upper,” “lower,” and other like terms are used for the convenience of the reader in reference to the drawings. Also, a person skilled in the art should notice this description may contain other terminology to convey position, orientation, and direction without departing from the principles of the present invention. 
     An embodiment of the invention, as shown and described by the various figures and accompanying text, provides a method of fabricating a lighting device. Referring now to  FIG. 1   a , a side view of a partially completed lighting device die  100  according to an embodiment of the present invention is presented. The lighting device die  100  may include a substrate  102  and a first light emitting diode (LED)  104 . The first LED  104  may be comprised of a first semiconductor layer  106 , an active region  108 , and a second semiconductor layer  110 . The second semiconductor layer  110  may have associated with it a surface  112 . The surface  112  may be a top surface. Generally, the surface  112  may be opposite the surface of the second semiconductor layer  110  that forms the active region  108 . 
     In one embodiment, the substrate  102  may comprise sapphire, silicon, silicon carbide, silicon carbide-on-silicon, gallium nitride, gallium nitride-on-sapphire, gallium arsenide, spinel, zinc oxide, and/or indium phosphide. In one embodiment, the first and second semiconductor layers  106 ,  110  may comprise group-III nitrides and/or group-III arsinides and/or group-III phosphide layers and/or group V hybrides. The aforementioned materials are exemplary only, do not limit the scope of the invention, and other semiconductor materials can also be used for the substrate  112 , the first semiconductor layer  106 , and the second semiconductor layer  110 . 
     In one manufacturing approach, an epitaxial growth method such as molecular beam epitaxy, vapor phase epitaxy, metalorganic chemical vapor deposition (MOCVD), or similar manufacturing methods may be used in the deposition of each of the first semiconductor layer  106 , the active region  108 , and the second semiconductor layer  110 . 
     Each of the first semiconductor layer  106  and second semiconductor layer  110  may be doped so as to form a p-n junction with the active region  108  positioned intermediately such that as electrons flow between the first semiconductor layer  106  and the second semiconductor layer  110  the active region  108  may emit photons, hereinafter referred to as light. For example, the first semiconductor layer  106  may be a p-type doped semiconductor material, and the second semiconductor layer  110  may be an n-type dopes semiconductor material, or vice-versa. Moreover, each if the first semiconductor layer  106  and the second semiconductor layer  110  may be comprised of a single layer of deposited material, a plurality of layers of the same or similar material, or a plurality of layers of varying materials. 
     Referring now to  FIG. 1   b , the lighting die  100  of  FIG. 1   a  is depicted having a layer of conductive material  114  positioned on the surface  112  of the second semiconductor layer  110 . The layer of conductive material  114  may positioned on the surface  112  by any appropriate means or methods, including, but not limited to, ink jet deposition. The layer of conductive material  114  may be generally coextensive with the second semiconductor layer  110 , may extend beyond the periphery of the second semiconductor layer  110 , or may be within the periphery of the second semiconductor layer  110 . The thickness of the layer of conductive material  114  may be uniform or may vary. The layer of conductive material  114  may be attached to the surface  112  of the second semiconductor layer  110  so as to prevent relative movement therebetween. 
     Referring now to  FIG. 1   c , the lighting die  100  of  FIG. 1   b  is depicted having a third semiconductor layer  118  positioned on a surface  116  of the layer of conductive material  114 , a second active region  120 , and a fourth semiconductor layer  122 . The third semiconductor layer  118 , the second active region  120 , and the fourth semiconductor layer  122  may be configured so as to combine to form a second LED  124 . In some embodiments, the third semiconductor layer  118  may be a p-type dopes semiconductor material and the fourth semiconductor layer  122  may be an n-type doped semiconductor layer, or vice-versa. The third semiconductor layer  118  and the fourth semiconductor layer  122  may be formed by any of the methods and composed of any of the material described hereinabove. 
     The third semiconductor layer  118  may be attached to the surface  116  of the layer of conductive material  114  so as to prevent relative movement therebetween. Moreover, the third semiconductor layer  118  may be coextensive with the periphery of the layer of conductive material  114 , extend beyond the periphery of the layer of conductive material  114 , or be within the periphery of the layer of conductive material  114 . 
     Each of the first LED  104  and the second LED  124  may be configured to emit lighting within a wavelength range corresponding to a color. More specifically, the first LED  104  may be configured to emit lighting within a first wavelength range corresponding to a first color, and the second LED  124  may be configured to emit light within a wavelength range corresponding to a second color. The first color may be the same as or similar to the second color, or the first color may be different from the second color. 
     Furthermore, in some embodiments, each of the first LED  104  and the second LED  124  may be configured to control the necessary forward voltage to cause each of the first LED  104  and the second LED  124  to operate. In some embodiments, the forward voltage may be the approximately equal, or it may be different. Moreover, depending on the type of semiconductor material used in forming each of the first semiconductor layer  106 , the second semiconductor layer  110 , the third semiconductor layer  118 , and the fourth semiconductor layer  122 , there may be an intended direction of flow of current, such as from the first LED  104  to the second LED  124 . In such an embodiment, the anode of the LED with the lower forward voltage requirement may be configured to be in electrical communication with the cathode of the LED with the greater forward voltage requirement. For example, in embodiments where the second semiconductor layer  110  is an n-type semiconductor, the third semiconductor layer  118  may be a p-type semiconductor, thereby enabling the concurrent forward operation of each of the first LED  104  and the second LED  124 . The material forming each of the first LED  104  and the second LED  124  may be selected so as to result in the flow of current through the desired series of LEDs. 
     Additionally, in some embodiments, the layer of conductive material  114  may have a thickness sufficient to prevent the formation of an active region between the second semiconductor layer  110  and the third semiconductor layer. Moreover, the layer of conductive material  114  may be configured so as to enable the flow of current from the first LED  104  to the second LED  124 . In some embodiments, the layer of conductive material  114  may be formed of a translucent material, permitting light emitted from either of the first LED  104  and the second LED  124  to propagate therethrough. For example, the layer of conductive material  114  may be formed of a transparent conducting film (TCF), such as, for example, polyethylene terephthalate (PTE), indium tin oxide (ITO), fluorine-doped tin oxide (FTO), doped zinc oxide, carbon nanotube films, grapheme films, poly(3,4-ethylenedioxythiophene) (PEDOT) and its derivatives, and any other conductor that permits the propagation of light therethrough. 
     Referring now to  FIG. 1   d , the lighting die  100  of  FIG. 1   c  is depicted with the substrate having been removed. The removal of the substrate may be accomplished by any suitable means or method, including, but not limited to, laser etching, chemical etching, grinding, cleaving, and all other methods known in the art. Once the substrate has been removed, each of the first semiconductor layer  102  and the fourth semiconductor layer  122  may be attached to a conductive member, such as a wire, and integrated into a circuit. As such, the lighting die  100  may operate as a monolithic lighting device comprising two light sources, namely the first LED  104  and the second LED  124 . 
     Referring now to  FIG. 2 , an embodiment of a plurality of lighting dies  200  is depicted. In some embodiments, the plurality of lighting dies  200  may each include a first LED  202 , and layer of conductive material  204 , and a second LED  206 , each of which may be formed as described hereinabove. Furthermore, in some embodiments, the plurality of lighting dies  200  may be formed as a single lighting die substantially has described hereinabove. Once so formed, a plurality of trenches  208  may be formed in the single lighting die so as to form the plurality of lighting dies  200 . The plurality of trenches  208  may be formed by any appropriate means or method, including, but not limited to, laser etching, chemical etching, drilling, or any other method known in the art. Each of the plurality of troughs  208  may penetrate through each of the second LED  206 , the layer of conductive material  204 , and the first LED  202  so as to form discrete monolithic lighting dies as described hereinabove. Each discrete monolithic lighting die may be electrically isolated from each other discrete monolithic lighting die. Moreover, the plurality of troughs  208  may optionally penetrate through a substrate on which the plurality of lighting dies  200  may be formed, resulting in physical separation of each discrete monolithic lighting die. Alternatively, the substrate may be removed separate and apart from the formation of the plurality of troughs  208 , so as to simultaneously detach each discrete monolithic lighting die of the plurality of lighting dies  200  from each other, permitting each of the discrete monolithic lighting dies to detach and be removable. 
     Referring now to  FIG. 3 , a side view of a lighting die  300  according to an embodiment of the invention is depicted. The lighting die  300  may be substantially similar to the lighting die  100  depicted in  FIG. 1   c , including a first LED  302 , a first layer of conductive material  304 , and a second LED  306 , and further including a second layer of conductive material  308  attached to a surface  310  of the second LED  306  similar to the attachment of the first layer conductive material  304  to a surface of the first LED  302  described hereinabove, and a third LED  314  attached to a surface  312  of the second layer of conductive material  308 , again similarly attached as described hereinabove. The third LED  314  may be configured similarly to the configuration of each of the first LED  302  and the second LED  306  hereinabove, both in terms of the individual characteristics of the LED and its cooperation with the first LED  302  and the second LED  306 . For example, the third LED  314  may have a required forward voltage that is less than the required forward voltage for the second LED  306 , which is in turn less than the required forward voltage for the first LED  302 . Similarly, the third LED may be configured to emit light within a wavelength range corresponding to a color that is approximately equal to or different from the color of light emitted by each of the first LED  302  and the second LED  304 . 
     It is contemplated that a lighting die may include any number of LEDs with a layer of conductive material positioned in between each pair of LEDs. Accordingly, lighting dies having four LEDs or more are contemplated and included within the scope of the invention. Moreover, the characteristics of each of the LEDs may be substantially as described hereinabove. 
     Referring now to  FIG. 4 , a monolithic lighting device  400  according to an embodiment of the present embodiment is depicted. The monolithic lighting device  400  may include a first LED  402  having a side surface  404  and an end surface  405 , a layer of conductive material  406  having a side surface  408 , and a second LED  410  also having a side surface  412  and an end surface  413 . In the present embodiment, each of the first LED  402 , the layer of conductive material  406 , and the second LED  410  are formed into a rectangular configuration such that each of their respective side surfaces  404 ,  408 ,  412  include four sections. Other configurations are contemplated and included within the scope of the invention, including, but not limited to, circles, ellipses, ovals, triangles, squares, and any other polygon. 
     In some embodiments, the monolithic lighting device  400  may further include a color conversion layer  414 . The color conversion layer  414  may be positioned on any of the side surfaces  404 ,  408 ,  412  and any of the end surfaces  405 ,  413 . The color conversion layer  414  may be configured to receive a source light within a first wavelength range and emit a converted light within a second wavelength range. Accordingly, the color conversion layer  414  may be configured to receive lighting within a wavelength range corresponding to the wavelength range of a light source that is in optical communication with the color conversion layer  414 . Where the color conversion layer  414  is positioned on the side surface  404  of the first LED  402 , it may be considered in optical communication with the first LED  402 , and, similarly, a color conversion layer  414  positioned on the side surface  412  of the second LED  410  may be considered in optical communication with the second LED  410 . Where the color conversion layer  414  is positioned on the side surface  408  of the layer of conducting material  406 , it may be considered in optical communication with each of the first LED  402  and the second LED  410 . When the color conversion layer  414  is in optical communication with two or more light sources, it may be configured to receive light within a wavelength range corresponding to all of the wavelength ranges of the source lights emitted by the light sources, or it may be configured to receive light within a wavelength range corresponding to a subset of the wavelength ranges of the source lights emitted by the light sources. For example, where the color conversion layer  414  may be configured to receive source lights within a wavelength range corresponding to a wavelength range of light emitted by the first LED  402 , but not the second LED  410 , or vice versa, or it may be configured to receive light from both the first LED  402  and the second LED  410 . The various permutations of combinations of source lights received by the color conversion layer  414  are contemplated and included within the scope of the invention. 
     The color conversion layer  414  may be formed of any material capable of receiving a source light within a first wavelength range and emitting a converted light within a second wavelength range. Types of materials include, but are not limited to, phosphors, luminescents, quantum dot materials, and dyes. All other non-recited materials capable of performing such a color conversion are contemplated and included within the scope of the invention. 
     The color conversion layer  414  may be configured into first and second sections  416 ,  418 , each of the sections  416 ,  418 , being configured to perform a color conversion of light emitted by light sources in optical communication therewith. For example, in the present embodiment, the first section  416  may be positioned in optical communication with the first LED  402  and configured to perform a color conversion on light emitted by the first LED  402 . Similarly, the second section  418  may be positioned in optical communication with the second LED  410  and configured to perform a color conversion on light emitted by the second LED  410 . Moreover, the first section  416  may be configured to not perform a color conversion on light emitted by the first LED  402 , and the second section  418  may be configured to not perform a color conversion on light emitted by the second LED  410 . The color conversion layer  414  comprising two sections is exemplary only, and any number of sections is contemplated and included within the scope of the invention. 
     Additionally, the color conversion layer  414  may be configured to have an emission latency. In some embodiments, an emission latency may be thought of as a period of time that elapses between the color conversion layer  414  receiving a source light and emitting a converted light. The color conversion layer  414  may be configured to have an emission latency designed to reduce or eliminate flicker. In some embodiments, flicker may be thought of as the perceptible variation of luminous intensity of light emitted by the monolithic lighting device. Flicker may be periodic or aperiodic. 
     Where the monolithic lighting device  400  is electrically coupled with a power source having a varying voltage, one of the first LED  402 , the second LED  410 , or both, may emit light responsive to the variance of the voltage. For example, where the monolithic lighting device  400  is electrically coupled to an alternating current (AC) power supply, when the voltage supplied by the AC power supply falls below a certain voltage, one of the first LED  402  and the second LED  410 , or both, may cease to emit light. When the voltage supplied by the AC power supply rises above a certain voltage, first LED  402  and/or the second LED  410  may resume emitting light. The period that elapses between the first LED  402  and/or the second LED  410  ceasing and then resuming emitting light may be perceptible, and hence may be considered flicker. The color conversion layer  414  may be configured to include an emission latency such that when the color conversion layer  414  receives light from one or both of the first LED  402  and the second LED  410 , a period of time may elapse before the color conversion layer  414  emits converted light. Where the period of the AC power supply is predictable, the emission latency of the color conversion layer  414  may be configured to by asynchronous with the period of non-emission of one or both of the first LED  402  and the second LED  410 . Put another way, the emission latency of the color conversion layer  414  may be configured to prevent any noticeable decrease in the luminous intensity of light emitted by the monolithic lighting device  400 . For example, the emission latency may be configured to be asynchronous with a power supply having a frequency within the range of about 1 Hz to about 240 Hz, including about 50 Hz, about 60 Hz, about 100 Hz, and about 120 Hz. Additionally, the emission latency may be configured to be asynchronous with a polyphase frequency. 
     Referring now to  FIG. 5 , a schematic circuit diagram of a lighting device  500  according to an embodiment of the present invention is depicted. The lighting device  500  may include a first LED  502 , a second LED  504 , and an Nth LED  506  electrically coupled to each other in a series configuration, wherein the Nth LED  506  may be the last of any number of LEDs coupled in series, forming a plurality of serially connected LEDs. The lighting device  500  may further include a first resistor  508 , a second resistor  510 , and an Nth resistor  511 . The first resistor  508  may be electrically coupled at a first end to a node formed between a cathode of the first LED  502  and an anode of the second LED  504 , and at a second end to a ground  512 . The ground  512  may be included as part of the lighting device  500  or it may be an external element. Similarly, the second resistor  510  may be electrically coupled at a first end to a node formed between a cathode of the second LED  504  and an anode of the next serially coupled LED, for instance, the Nth LED  506 , and the Nth resistor  511  may be electrically coupled at a first end to a node formed between an anode of the Nth LED  506  and a cathode of a preceding LED in the plurality of serially connected LEDs, for instance, the second LED  504 . Furthermore, an anode of the first LED  502  may be electrically coupled to a power supply  514 . Similar to the ground  512 , the power supply  514  may be included as part of the lighting device  500  or it may be an external element. Also, a cathode of the Nth LED  506  may be electrically coupled to the ground  512 . The lighting device  500  may include any number of serially connected LEDs and associated resistors. 
     Each of the serially coupled LEDs  502 ,  504 ,  506  may have a known required forward voltage, which may be understood as the voltage that is required for the LED to operate, and a known forward voltage drop, which may be understood as a drop in voltage across the LED when the LED is emitting light. Each of the first LED  502 , the second LED  504 , and the Nth LED  506  may be arranged such that the first LED  502  has the greatest required forward voltage, the second LED  504  have a required forward voltage that is less than or approximately equal to the required forward voltage of the first LED  502 , and the Nth LED  506  have a required forward voltage that is less than or approximately equal to the preceding LED in the serially connected LEDs, for instance the second LED  504 . Accordingly, when a voltage applied by the power supply  514  to the anode of the first LED  502  is approximately equal to or greater than the required forward voltage of the first LED  502 , the first LED  502  will operate to emit light, and current will flow through the first LED  502 . Accordingly, a voltage will be applied to the anode of the second LED  504 . However, the voltage will be approximately the voltage applied to the anode of the first LED  502  less the forward voltage drop of the first LED  502 . If the voltage applied to the anode of the second LED  504  is greater than the required forward voltage of the second LED  504 , the second LED will operate to emit light and current will flow therethrough. However, if the voltage applied to the anode is less than the required forward voltage of the second LED  504 , the second LED  504  will prevent the flow of current therethrough, and current will instead flow through the first resistor  508 . Accordingly, where the voltage of current flowing from the cathode of the first LED  502  is greater than or approximately equal to the required forward voltage of the second LED  504 , both the first LED  502  and the second LED  504  will operate to emit light, but if it is less than the required forward voltage of the second LED  504 , then only the first LED  502  will operate to emit light. Moreover, the first resistor  508  may be configured to have a resistance such that when the voltage applied to the anode of the second LED  504  is greater than its required forward voltage, very little current flows through the first resistor  508 . This sequence will continue down the plurality of serially connected LEDs, wherein an LED succeeding the second LED  504 , for instance, the Nth LED  506 , will have a voltage applied to its anode of the second LED  504  operates and has current flowing therethrough. Similar to the first resistor  508 , each of the second resistor  510  and the Nth resistor  511  may be configured to have a resistance to permit very little current to flow therethrough when the voltage applied to the associated LED anode is greater than or approximately equal to that LED&#39;s required forward voltage. The voltage applied may be approximately the voltage applied to the anode of the first LED  502  less the forward voltage drop of each of the first LED  502  and the second LED  504 . If the voltage applied to the anode of the Nth LED  506  is greater than or approximately equal to the required forward voltage of the Nth LED  506 , then it will operate, along with the first LED  502  and the second LED  504 . However, if the voltage applied to the anode of the Nth LED  506  is less than the required forward voltage, then current will instead flow through the Nth resistor  511 . Where the Nth LED  506  is the last serially connected LED, if the voltage applied to its anode is greater than its required forward voltage, current will flow therethrough and to the ground  512 . 
     Where the power source  514  provides power having a varying voltage, the number of LEDs of the plurality of serially connected LEDs will similarly vary. For instance, where the power source  514  is an AC power source having a frequency with associated phases defining the voltage supplied, when the power supply  514  provides power having a voltage greater than the required forward voltage of the first LED  502  but less than the required voltage of the first LED  502  in addition to the forward voltage drop of the first LED  502 , only the first LED  502  will illuminate. When the power supply  514  is in a later phase supplying an increased voltage, the voltage may be sufficient to illuminate more than the first LED  502  of the plurality of serially connected LEDs, such as, for instance, the second LED  504 , and the Nth LED  506 . The power supplied by the power supply  514  may be configured according to the required forward voltage of the Nth LED  506  as well as the forward voltage drop of all the LEDs preceding the Nth LED  506 . Moreover, the number of LEDs in the plurality of serially connected LEDs may be configured such that all the LEDs of the plurality of LEDs will be illuminated when the power supply  514  provides its maximum voltage. Where the power supply  514  is an AC power supply, it may be rectified, including half-wave and full wave. Moreover, the power supply  514  may be a triac power supply. 
     It is contemplated that the plurality of serially connected LEDs may be configured to emit light within a wavelength range associated by one color, or within a plurality of wavelength ranges corresponding to a variety of colors. Additionally, it is contemplated that one or more of the plurality of serially connected LEDs may include a color conversion layer. Moreover, where an LED comprises a color conversion layer, the color conversion layer may include an emission latency. The emission latency may be configured as described hereinabove. 
     The luminous intensity of the lighting device  500  may be thought of as the cumulative luminous intensity of the plurality of LEDs that are emitting light at a given point in time. Accordingly, where the power supply  514  is an AC power supply, the luminous intensity of the lighting device  500  will vary according to the number of LEDs that are emitting light at a given point in time. In order to prevent flicker, one or more of the plurality of serially connected LEDs may include a color conversion layer with an emission latency that is asynchronous with the frequency of the AC power supply, substantially as described hereinabove. Moreover, the lighting device  500  optionally include a color conversion layer that is remote from any of the plurality of serially connected LEDs, as will be discussed hereinbelow. 
     Referring now to  FIG. 6 , a monolithic lighting device  600  according to an embodiment of the present invention is depicted. The monolithic lighting device  600  may include a first LED  602  having a side surface  604  and an end surface  606 , a layer of conductive material  608  having a side surface  610 , and a second LED  612  having a side surface  614  and an end surface  616 . The monolithic lighting device  600  may further comprise an encapsulating layer  618  positioned substantially about the side surfaces  604 ,  610 , and  614  and/or the end surfaces  606  and  616 . The encapsulating layer  618  may be configured to permit electrical connectors to pass therethrough, permitting the electrical coupling of the monolithic lighting device  600  to a power supply. 
     In some embodiments, the encapsulating layer  618  may be at least partially formed of a transparent material, permitting the propagation of light therethrough. In some other embodiments, the encapsulating layer  618  may be formed at least partially of a heat-conducting material. Furthermore, the encapsulating layer  618  may be in thermal communication with at least one of the first LED  602 , the layer of conductive material  608 , and the second LED  612 . The encapsulating layer  618  may be configured to dissipate heat from any element of the monolithic lighting device  600  with which it is in thermal communication by conducting heat away from heat-generating elements and radiating heat into the environment surrounding the monolithic lighting device  600 . Moreover, in some other embodiments, the encapsulating layer  618  may be in thermal communication with another structure to further increase the rate of heat dissipation of the monolithic lighting device  600 . 
     Additionally, in some embodiments, the encapsulating layer  618  may be configured to include or function as a color conversion layer as described hereinabove. 
     Referring now to  FIG. 7 , a luminaire  700  according to an embodiment of the present invention is presented. The luminaire  700  may include a base  710 , an optic  720 , a first support  730 , a second support  740 , and a light source  750 . The luminaire  700  may be formed so as to conform to standardized dimensional requirements, such as, for example, light bulb standards A, B, G, MR, PAR, F, P, R, ER, IRC, and any other standard known in the art. Additionally, the base  710  may be configured to conform to standardized base configurations, including, for example, Edison screw, bi-pin, bi-post, wedge, bayonet, fluorescent base, and any other configuration known in the art. Moreover, the base  710  may include an electrical connector  712  configured to couple electrically with a power source. 
     The optic  720  may be attached to the base  710  so as to define an optical chamber  722 . The first support  730  may be attached at a first end  732  to the electrical connector  712 . More specifically, the first end  732  of the first support  730  may be attached to a positive terminal  714  of the electrical connector  712 . Similarly, the second support  740  may be attached at a first end  742  to a negative terminal  716  of the electrical connector  710 . Each of the first support  730  and the second support  740  may be configured to be electrically conductive along their length. Also, each of the first support  730  and the second support  740  may extend from the electrical connector  710  into the optical chamber  722 , diverging from each other. 
     In some embodiments, the light source  750  may include a plurality of serially connected LEDs  752 , such as in a monolithic lighting device as described hereinabove. Accordingly, the light source  750  may have a positive end  754  corresponding to the anode of the first LED of the plurality of serially connected LEDs  752 , and a negative end  756  corresponding to at least one of the cathode of the last LED of the plurality of serially connected LEDs  752  and one or more of a plurality of resistors electrically coupled to nodes between pairs of LEDs, substantially as described hereinabove, or both. The positive end  754  may be attached and electrically coupled to a second end  734  of the first support  730 , and the negative end  756  may be attached and electrically coupled to a second end  744  of the second support  740 . Accordingly, the positive end  754  may be positioned in electrical communication with the positive terminal  714  of the electrical connector  712 , and the negative end may be positioned in electrical communication with the negative terminal  716  of the electrical connector  712 . Furthermore, the light source  750  may be carried by the first support  730  and the second support  740  such that it is suspended within the optical chamber  722 . 
     When current is received from a power supply through the electrical connector  712 , the current may travel through the positive terminal  714  to the first support  730  and to the positive end  754  of the light source  750 . The current may then travel through the plurality of serially connected LEDs  752  substantially as described in the various embodiments presented hereinabove. Light emitted by the light source  750  may propagate through the optical chamber  722  and through the optic  720 , then into the environment surrounding the luminaire  700 . The current may illuminate some, all, or none of the plurality of LEDs  752  before flowing to the negative end  756  of the light source  750 , then through the second support  740  and to the negative terminal  716  of the electrical connector  712 . Hence, a circuit is formed between the luminaire  700  and the power supply. The luminous intensity of light emitted by the light source  750 , and hence the luminaire  700 , may vary according to the voltage supplied to the luminaire  700  by the power supply. 
     In some embodiments, the light source  750  may include a color conversion layer positioned on one or more of the plurality of serially connected LEDs  752  as described hereinabove. In some embodiments, the light source  750  may include an encapsulating layer of material disposed substantially about the light source  750 . The encapsulating layer may be an encapsulating layer as described hereinabove, and may optically be in thermal communication with heat-generating elements of the light source  750 . Furthermore, the encapsulating layer may be in thermal communication with one or both of the first support  730  and the second support  740 , which may serve to further increase the rate of heat dissipation from the light source  750 . 
     In some embodiments, the optic  720  may further include an inside surface  724 . Furthermore, a color conversion layer  726  may be attached to the inside surface  724 . The color conversion layer  726  may include the various features as described hereinabove, including a configured emission latency configured to be asynchronous with a frequency of the power supply. 
     Referring now to  FIG. 8 , a luminaire  800  according to an embodiment of the present invention is depicted. The luminaire  800  may be similar to the luminaire  700  as depicted in  FIG. 7 , including a base  810 , an optic  820 , a first support  830 , a second support  840 , and a light source  850 . However, each of the first support  830  and the second support  840  may be electrically coupled with both of a positive terminal  812  and a negative terminal  814  of an electrical connector  816  of the base  810 . Each may include a positive terminal  832 ,  842  and a negative terminal  834 ,  844  at an end  836 ,  846 . 
     The light source  850  may include a first monolithic lighting device  852  comprising a plurality of serially connected LEDs  854  and a second monolithic lighting device  856  comprising a plurality of serially connected LEDs  858 . The first monolithic lighting device  852  may be attached to the positive terminal  832  of the first support  830  and the negative terminal  844  of the second support  840  such that when current flows through the forward operation of the plurality of LEDs  854  occurs when current flows through the first monolithic lighting device  852  from the positive terminal  832  to the negative terminal  844 . Similarly, the second monolithic lighting device  856  may be attached to the positive terminal  842  of the second support  840  and the negative terminal  834  of the first support  830  such that when current flows through the forward operation of the plurality of LEDs  858  occurs when current flows through the second monolithic lighting device  856  from the positive terminal  842  to the negative terminal  834 . Accordingly, the first monolithic lighting device  852  may be in a generally opposite orientation compared to the second monolithic lighting device  856 . 
     When the electrical connector  816  is positioned in electrical communication with a power source, current from the power source may flow the positive terminal  812  to the positive terminals  832 ,  842  of each of the first support  830  and the second support  840 . From there, the current may flow through each of the first monolithic lighting device  852  and the second monolithic lighting device  856 , illuminating LEDs substantially as described for the light source  750  described in  FIG. 7 . Due to their generally opposite orientation, each of the plurality of LEDs  854 ,  858  will illuminate in generally opposite order. Put another way, the plurality of LEDs  854  will illuminate from the first support  830  toward the second support  840 , and the plurality of LEDs  858  will illuminate from the second support  840  toward the first support  830 . 
     In some embodiments, one or both of the first and second monolithic lighting devices  852 ,  856  may include a color conversion layer or an encapsulating layer, substantially as described in the embodiment depicted in  FIG. 7 . Additionally, in some embodiments, the optic  820  may include a color conversion layer, also substantially as described in the embodiment depicted in  FIG. 7 . 
     In another embodiment of the invention, a method of fabricating a lighting device is presented. The method may include the step of first providing a substrate having a surface. A masking layer may then be selectively deposited on a first section of the surface of the substrate. A first LED may then be formed on a second section of the substrate and a second LED may be formed on a third section of the substrate, by any method disclosed hereinabove. Each of the second section and the third section may be adjacent with the first section, such that the first section is intermediate the second and third sections. The method may further include removing the mask by any appropriate means, such as etching, drilling, or chemical bath. A conductive trace may then be deposited on the first section of the surface of the substrate so as to couple electrically the first LED and the second LED by any method disclosed hereinabove. This process may be extended to any number of LEDs and intermediate electrical traces, producing a plurality of serially connected LEDs. Moreover, the plurality of serially connected LEDs may be generally collinear. The method may optionally include the step of removing the substrate. 
     Some of the illustrative aspects of the present invention may be advantageous in solving the problems herein described and other problems not discussed which are discoverable by a skilled artisan. 
     While the above description contains much specificity, these should not be construed as limitations on the scope of any embodiment, but as exemplifications of the presented embodiments thereof. Many other ramifications and variations are possible within the teachings of the various embodiments. While the invention has been described with reference to exemplary embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best or only mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims. Also, in the drawings and the description, there have been disclosed exemplary embodiments of the invention and, although specific terms may have been employed, they are unless otherwise stated used in a generic and descriptive sense only and not for purposes of limitation, the scope of the invention therefore not being so limited. Moreover, the use of the terms first, second, etc. do not denote any order or importance, but rather the terms first, second, etc. are used to distinguish one element from another. Furthermore, the use of the terms a, an, etc. do not denote a limitation of quantity, but rather denote the presence of at least one of the referenced item. 
     Thus the scope of the invention should be determined by the appended claims and their legal equivalents, and not by the examples given.