Patent Publication Number: US-2013242566-A1

Title: Light emitting diode lamp

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the benefit of Korean Patent Application No. 10-2012-0026945, filed on Mar. 16, 2012, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference. 
     BACKGROUND 
     1. Technical Field 
     The present disclosure relates to a light emitting diode (LED) lamp, and more particularly, to an LED lamp implementing omni-directional or directional emitted light according to whether a securely connectable but detachable reflector is connected thereto. 
     2. Description of the Related Art 
     A light emitting diode (LED) refers to a semiconductor device that emits light as an electric current flows. That is, the LED refers to a p-n junction diode including gallium arsenic (GaAs), Ga nitride (GaN) optical semiconductors, as an electronic part that converts electrical energy to optical energy. 
     Recently, a blue LED and an ultraviolet (UV) LED using nitrides having excellent physical and chemical characteristics have been introduced. Since the blue LED or UV LED may implement white light or other monochromatic lights using a phosphor material, an application field of the LED is expanding. 
     The LED has a relatively long life, and may be implemented in a small size and a low weight. Also, since the LED has strong directivity of light emission, low-voltage driving is available. In addition, the LED is durable against impact and vibration and does not require preheating and complicated driving and therefore is applied to various uses. For example, in recent days, the application fields of the LED are expanding from small lighting for a mobile terminal to general interior and exterior lighting, vehicle lighting, a backlight unit (BLU) for a large-area liquid crystal display (LCD), and the like. 
     General lighting such as an incandescent lamp and a compact fluorescent lamp (CFL) emit light omni-directionally due to characteristics of their light sources. Since most lighting devices are manufactured according to this omni-directional characteristic, a lamp embodying the LED has to emit light omni-directionally. Omni-directional as used herein is intended broadly to refer to light emissions that, rather than being directed substantially along a unidirectional path or axis, instead are directed along multiple (but not necessarily all) different axes emanating from the light source. 
     However, when the LED lamp is used as a down light to emit light in a downward direction, the LED needs to be directional. In this regard, a lamp device such as a reflector needs to be used in spite of a certain degree of light loss. 
     That is, after one of different types of LED lamps is selected according to required directivity, and then the selected LED lamp is connected to the lamp device. However, in this case, since a great number of LED lamps are to be used, use and maintenance costs and complexities including materials and labor (e.g. labor expended to replace one or more LED lamps) may increase. 
     Accordingly, there is a desire for a new LED lamp achieving both directional and omni-directional light. 
     SUMMARY 
     An aspect of the present disclosure provides a light emitting diode (LED) lamp capable of achieving omni-directional or directional light emitted from an LED using a structure in which a reflector is connected to or separated from a mounting housing including an LED. 
     Another aspect of the present disclosure provides an LED lamp capable of minimizing optical loss by connecting or separating a reflector according to use conditions, and accordingly increasing emission efficiency. 
     Still another aspect of the present disclosure provides an LED lamp implementing required directivity of light by connecting a selected one of a plurality of reflectors to a mounting housing, and accordingly reducing costs since replacement of the entire lamp is unnecessary. 
     According to an aspect of the present disclosure, there is provided a light emitting diode (LED) lamp including a mounting housing including a printed circuit board (PCB) in the form of a circular or so-called “hollow” (i.e. having a concentric through hole therein) or annular disc, at least one LED disposed (e.g. mounted) on the PCB, and a cover portion shaped to correspond to a shape of the PCB and connected to the mounting housing to cover the PCB on which the at least one LED is mounted, thereby covering the at least one LED, wherein light emitted from the at least one LED is directional. 
     Plural ones of the at least one LED may be arranged at uniform distances or spacings across or along the PCB, and the cover portion may be provided in a circular annular shape so as to cover the plural LEDs. 
     The cover portion may include a pair of side cover members disposed at opposite sides of the PCB to which the at least LED is mounted, along the PCB, and an upper transmission member configured to connect upper ends of the pair of side cover members and to transmit the light emitted from the at least one LED to the outside of the housing. 
     A distance or angle between the pair of side cover members may increase toward the mounting housing in a downwardly, inwardly tapered form, and the mounting housing may include an insertion groove in which first ends of the pair of side cover members are inserted and fitted or otherwise connected. 
     The pair of side cover members may be made of an opaque or translucent material, and the upper transmission member may be made of a transparent material. 
     The LED lamp may further include a reflector detachably connected to the mounting housing or to the cover portion, and the reflector configured to reflect the light emitted from the at least one LED in other directions including laterally outward (e.g. radial) or laterally outward and downward (radial) directions. 
     The reflector may be detachably connected to the mounting housing or the cover portion by being partially inserted in an interior round region of the mounting housing defined with an annular outer region of the cover portion, in what will be referred to herein as an interference fit. 
     The LED lamp may further include at least one connection portion of which one end is fixed to the reflector and an opposite end is detachably connected to the mounting housing or to the cover portion. 
     The reflector may be provided in a funnel shape of which a diameter increases in a direction away from the mounting housing, the reflector extending to at least a part of an upper area of the cover portion. 
     At least a part of the reflector may be curved so that the light emitted from the LED is reflected from the reflector and directed to a front (upper region), lateral sides, and lower lateral sides. 
     According to another aspect of the present disclosure, there is provided an LED lamp including a mounting housing including a PCB, at least one LED disposed on the PCB, a cover portion connected to the mounting housing to cover the PCB to which the at least one LED is mounted, thereby covering the at least one LED, and a reflector detachably connected to the mounting housing or the cover portion and configured to reflect light emitted from the at least one LED in other directions including lateral (e.g. radial) directions, wherein the light emitted from the at least one LED is reflected from the reflector and emitted omni-directionally when the reflector is provided. 
     The PCB may be provided in a circular or annular disc shape, plural ones of the at least one LED may be arranged at a uniform distance or spacing across or along the PCB, and the cover portion may be provided in an annular shape so as to cover plural ones of the at least one LED. 
     The LED lamp may further include at least one connection portion of which one end is fixed to the reflector and an opposite end is detachably connected to the mounting housing or to the cover portion. 
     The reflector may be provided in a funnel shape of which a diameter increases in a direction away from the mounting housing, the reflector extending to at least a part of an upper area of the cover portion. 
     EFFECT 
     According to some embodiments of the present disclosure, omni-directional or directional light emitted from an LED may be achieved by a structure in which a reflector is connected to or separated from a mounting housing including an LED. 
     Additionally, according to some embodiments of the present disclosure, since a reflector may be connected or separated according to use conditions, optical loss may be minimized, and accordingly emission efficiency may be increased. 
     Additionally, according to some embodiments of the present disclosure, required directional light may be achieved by mounting a selected one of a plurality of reflectors to a mounting housing. Accordingly, since replacement of the entire lamp is not required as in related arts, material and labor costs may be reduced. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       These and/or other aspects, features, and advantages of the invention will become apparent and more readily appreciated from the following description of exemplary embodiments, taken in conjunction with the accompanying drawings of which: 
         FIG. 1  is an isometric view illustrating a light emitting diode (LED) lamp comprising one or more LEDs, according to an embodiment of the present disclosure; 
         FIG. 2  is a front view of  FIG. 1 ; 
         FIGS. 3A and 3B  are a cross-sectional front view and a top plan view, respectively, schematically illustrating the light-directing cover portion of the LED lamp of  FIGS. 1 and 2  and a resulting directional light emitted from the one or more LEDs; 
         FIG. 4  is a diagram illustrating a state before a reflector is connected to the LED lamp shown in  FIG. 1 ; 
         FIG. 5  is a diagram illustrating a state in which the reflector shown in  FIG. 4  is applied to the LED lamp shown in  FIG. 1 ; 
         FIG. 6  is a diagram schematically illustrating a state in which light emitted from the internal parts and the LED of  FIG. 5  is reflected by the reflector at multiple, diffused angles from the light source; 
         FIG. 7  is a diagram illustrating an LED lamp according to another embodiment of the present disclosure; and 
         FIG. 8  is a diagram illustrating an LED lamp according to still another embodiment of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     Reference will now be made in detail to exemplary embodiments of the present disclosure, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the like elements throughout. A following description is one of various aspects of the present disclosure. Also, the following description forms part of the detailed description of the illustrated embodiments. 
     However, in describing the embodiments, if detailed descriptions of related disclosed art or configuration are determined to unnecessarily make the subject matter of the present disclosure obscure, they will be omitted. 
       FIG. 1  is an isometric view illustrating a light emitting diode (LED) lamp according to an embodiment of the present disclosure.  FIG. 2  is a front view of  FIG. 1 .  FIGS. 3A and 3B  are cross-sectional front and top plan views schematically illustrating a light-directing cover portion of the LED lamp and a resulting directional light emitted from the one or more LEDs of the LED lamp. 
     As shown in the drawings, the LED lamp  100  according to some embodiments may include a mounting housing  110  forming a basic appearance of the LED lamp and including an annular printed circuit board (PCB)  111  mounted along an outer circumference of an upper surface of the mounting housing  110  with reference to  FIG. 1 , a plurality of LEDs  120  arranged at uniform distances or spacing across or along an upper surface of the PCB  111 , and a light-directing cover portion  130  connected to the mounting housing  110  to cover the LEDs  120  and the PCB  111 . It will be understood that LED lamp  100  may also have a conventional base portion for threaded installation in a standard light bulb socket, and an optional conventional transformer (not shown) for converting alternating current (AC) to direct current (DC) if needed. 
     The LED lamp  100  may further include a detachable reflector  150  (refer briefly to  FIGS. 4-8 ) configured to change a direction of light emitted from the LEDs  120  from the upward or forward direction to radial or plural lateral and/or lateral downward directions. The reflector  150  will be described later in further details in accordance with various illustrative but not limiting embodiments thereof. 
     As shown in  FIG. 1 , the mounting housing  110  mounts components such as the LEDs  120 , and forms the overall shape and appearance of the LED lamp  100 . The mounting housing  110  may have radial fins, as shown in  FIG. 1 , or its outer surface may be smooth or coated or textured or otherwise ornamented for aesthetic effect. 
     A substrate, for example, the PCB  111  of the present embodiment, may be mounted to one surface of the mounting housing  110 . The PCB  111 , being in the form of an annular disc, may extend along the outer circumference of the one surface of the mounting housing  110 . Two or more, e.g. a plurality, of LEDs  120  may be mounted in an annular arrangement along the outer annular region of the annular PCB  111  and may be generally equally spaced therealong. 
     Referring to  FIG. 1 , a total of six LEDs  120  are arranged at uniform distances along the PCB  111 , such that the light emitted from the LEDs  120  may illuminate the outside according to some embodiments. 
     Although not shown, each of the LEDs  120  may include a first type semiconductor layer, an active layer, and a second type semiconductor layer. By application of electric power, light may be emitted by recombination of electrons and holes at the active layer. 
     The light emitted from the LEDs  120  may be emitted to a front of the LED lamp as shown in  FIG. 2 . That is, directional light may be emitted away from the mounting housing  110  and toward the front of the lamp  100 . 
     As shown in  FIG. 2 , the cover portion  130  may cover and protect the LEDs  120  and the PCB  111  mounting the LEDs  120 , and guide the light emitted from the LEDs  120  toward the front of the LED lamp  100 . For this purpose, the cover portion  130  may be in an annular shape corresponding to a shape of the PCB  111 , with an upper region of the cover portion being selectively configured to transmit light. 
     In detail, as shown in  FIGS. 3A and 3B , the light-directing cover portion  130  may include a pair of inner and outer annular side cover members  131  and  131 ′ disposed on the PCB  111  mounting the LEDs  120  (only two LEDs being shown in  FIG. 3A , and neither the LEDs nor the PCB being shown in  FIG. 3B , for the sake of clarity), and an upper transmission member  135  connected to upper ends of the pair of side cover members  131  and  131 ′. (It will be understood that less than all of this detail is shown in  FIGS. 1 and 2  for the sake of clarity so as not to obscure the arrangement of the one or more LEDs and the PCB beneath the light-directing cover portion.) 
     The pair of side inner and outer cover members  131  and  131 ′ may be made of an opaque or translucent material not allowing much transmission of the light emitted from the LEDs  120 . As shown in  FIG. 3 , a “distance” between the pair of side cover members  131  and  131 ′ may increase toward the mounting housing  110  to form what will be referred to herein as downwardly (i.e. toward the mounting housing) and outwardly angled sidewalls. (This increasing distance will be understood to correspond with the increase between distance A and distance B in  FIG. 3A  and the angle C represented thereby.) Lower ends of the pair of side cover members  131  and  131 ′ may be detachably connected in a corresponding pair of inner and outer insertion grooves  115  and  115 ′ formed on one surface  1105  of the mounting housing  110 . 
     According to the shape of the pair of side cover members  131  and  131 ′ and the structure of the pair of insertion grooves  115  and  115 ′ being angled or inclined, when the lower ends of the pair of side cover members  131  and  131 ′ are firmly inserted into the corresponding insertion grooves  115  and  115 ′ of the mounting housing  110 , the lower ends of the pair of side cover members  131  and  131 ′ may be securely connected within the insertion grooves  115  and  115 ′, so that a secure connection of the cover portion  130  with respect to the mounting housing  110  is maintained. 
     In addition, when the lower ends of the pair of side cover members  131  are firmly pulled from the mounting housing  110 , the cover portion  130  may be easily separated from the mounting housing  110 . That is, connection and separation of the light-directing cover portion  130  with respect to the mounting housing  110  may be performed with ease. 
     The upper transmission member  135  transmits the light emitted from the LEDs  120  and, for this purpose, may be made of a transparent material. The upper transmission member  135  may be disposed parallel with the front surface  1105  of the mounting housing  110  and may have a circular, circular-annular, or other suitable shape for connection with the pair of inner and outer side cover members  131  and  131 ′. 
     Owing to the shape of the cover portion  130 , the light emitted from the LEDs  120  may become directional or uni-directional, e.g. the one or more LEDs may emit light outwardly from the front of the lamp  100 . Thus, the LED lamp  100  may feature directional lamps as shown in  FIG. 2 . 
     Also, different from the above description, the LED lamp  100  may include omni-directional lamps. For this, the LEDs  120  may further include a reflector configured to reflect the light emitted from the LEDs  120  in other directions. 
     Various reflector embodiments now will be described with reference to  FIGS. 4-8 . 
       FIG. 4  is a diagram illustrating a condition of the invented lamp  100  before a reflector  150  is connected thereto.  FIG. 5  is a diagram illustrating a condition in which the reflector  150  shown in  FIG. 4  is applied to the LED lamp  100  shown in  FIG. 1 .  FIG. 6  schematically illustrates a condition in which light emitted from the internal parts and the LEDs of  FIG. 5  is reflected by the reflector into one or more generally radial, e.g. lateral or lateral and downward, rays or beams of light to produce an omni-directional LED lamp. 
     As shown in the drawings, the reflector  150  may be inserted in an inner space  110 S defined by the annular cover portion  130  and detachably connected to the mounting housing  110 . The reflector  150  may reflect the light emitted from the LEDs  120  in other directions, for example lateral (e.g. radial) directions, so that the light is emitted omni-directionally. Alternatively, the reflector  150  may be inserted into a concentric circular annular groove formed in an upper surface of a PCB that takes the form of a circular rather than an annular disk, with the reflector&#39;s bottom circular annular edge removably captured within the circular annular groove formed within the upper surface of the PCB&#39;s circular disk shape. 
     Referring to  FIGS. 4 and 5 , the reflector  150  may be in a substantial funnel shape. A lower end  151  of the reflector  150 , directed to the mounting housing  110 , may be shaped corresponding to the inner space  110 S so as to be detachably connected to the mounting housing  110  or to the cover portion  130 . An upper end  155  ( FIG. 6 ) extended from the lower end  151  may cover a part of an upper area of the cover portion  130 , thereby reflecting the light emitted from the LEDs  120 . 
     Since the reflector  150  is configured to be selectively connected to the mounting housing  110  as necessary, connection and separation of the reflector  150  with respect to the mounting housing  110  or the cover portion  130  may be easily performed. 
     For example, a locking recess (not shown) may be formed on a surface of the mounting housing  110  to lock a lower end of the reflector  150 , thereby achieving a secure connection between the mounting housing  110  and the reflector  150 . Also, separation may be easily performed as necessary by releasing the locking structure between the mounting housing  110  and the reflector  150 . However, the connection structure of the reflector  150  with respect to the mounting housing  110  or the cover portion  130  is not specifically limited to a locking recess and, in accordance with one embodiment of the invention, is achieved by a simple interference fit between reflector  150  and cover portion  130 . 
     According to the aforementioned structure of the reflector  150 , the light emitted from the LEDs  120  may be reflected by the reflector  150  and emitted to lower lateral sides, lateral sides, and upper lateral sides, and in an upward or partially frontal direction, that is, omni-directionally as shown in  FIG. 6 . 
     Thus, since direction of light emission may be conveniently controlled by connecting or separating the reflector  150 , the LED lamp  100  may be used more efficiently. For example, in a case that the LED lamp  100  is provided on a ceiling of an interior space, an omni-directional lamp may be achieved by connecting the reflector  150  or a directional lamp may be achieved by separating the reflector  150  as demanded by a user. 
     According to the embodiment of the present disclosure, the light emitted from the LEDs  120  may become omni-directional or directional according to a connection state of the reflector  150  with respect to the mounting housing  110  including the LEDs  120  and the cover portion  130 . In addition, since the reflector  150  is connected or separated according to use conditions, optical loss may be minimized, consequently increasing the optical efficiency of the LED lamp  100 . 
     Furthermore, when one of a plurality of reflectors  150  is selectively connected to the mounting housing  110 , a desired directivity of the light may be obtained. As a result, replacement of an entire lamp is not required as in related arts when it is desired by a user to change directivity. Therefore, cost may be reduced. 
     Hereinafter, an LED lamp according to another embodiment of the present disclosure will be described, omitting a description about the same structures as in the previous embodiment. 
       FIG. 7  is a diagram illustrating an LED lamp  200  according to another embodiment of the present disclosure in which a different one of a plurality of reflectors is used. 
     As shown in  FIG. 7 , the LED lamp  200  has substantially the same structure as the LED lamp  100  of  FIG. 6  except for the shape of a reflector  250 . The reflector  250  of the present embodiment covers an upper area of a cover portion  230  so that light emitted from LEDs  220  is restricted from emitting to a front of the LED lamp  200  but mainly is emitted radially, outwardly toward lateral sides or radially, outwardly and downwardly toward lower lateral sides. 
     In this case, since the light emitted from the LEDs  220  is reflected from the reflector  250  rather than being directly emitted, the light may be evenly dispersed without being focused on a certain area. 
     However, various types of reflectors not limited to the reflector  250  or the reflector  150  may be applied according to desired directivity of light. In this case, the desired directivity of light may be obtained by selecting one of various reflectors without having to replace the entire LED lamp. As a result, the cost may be reduced while the optical efficiency for a particular intended use of the LED lamp is increased. 
     Hereinafter, an LED lamp according to still another embodiment of the present disclosure will be described, omitting a description about the same structures as in the previous embodiments. 
       FIG. 8  is a diagram illustrating an LED lamp  300  according to still another embodiment of the present disclosure in which yet another one of the plurality of reflectors is used. 
     As shown in  FIG. 8 , the LED lamp  300  may include a mounting housing  310  including a PCB mounting a plurality of LEDs, and a dome-shaped cover portion  330  provided in a hemispherical shape and connected to the mounting housing  310  to cover the LEDs. The LED lamp  300  may further include a reflector  350  configured with symmetric internal light-reflecting surfaces to reflect light emitted from the LEDs radially outwardly and even downwardly, as shown. The reflector  350  may be detachably connected to the mounting housing  310  through a suitably configured, light-transmissive connection portion  370 . 
     The reflector  150  in the previous embodiment illustrated in  FIG. 4  is detachably connected in the inner space  110 S formed between the mounting housing  110  and the cover portion  130  being in the annular shape. However, according to the present embodiment, one end of the connection portion  350  is connected to the reflector  350  whereas an opposite end is detachably connected to the mounting housing  310  through the connection portion  370  which is connectable to an outer wall of the mounting housing  310  by any suitable connection mechanism including a locking recess (not shown) or a simple interference fit. 
     According to the present embodiment, directional light emitted from the LEDs may be reflected by the reflector  350  omni-directionally, thereby implementing an omni-directional lamp. In addition, by separating the reflector  350  from the mounting housing  310 , a directional lamp may also be implemented. 
     In the present embodiment, connection between the mounting housing  310  and the reflector  350  is achieved by the connection portion  370 . However, any other methods or structures may be applied to connect and separate the reflector  350  with respect to the mounting housing  310 . 
     In accordance with one embodiment of the invention, at least a portion, and preferably all, of the annular reflector is smoothly and concavely curved upwardly and outwardly away from a central longitudinal axis of the mounting housing, as is consistently illustrated herein in  FIGS. 4-8 . It will be understood that reflectors such as those described and illustrated herein may have any suitable reflecting cross-sectional shape, e.g. linear, circular, parabolic, or otherwise curvilinear, depending upon the desired application and its directivity and/or focus and/or collimated/diffused-light-emitting design requirements. 
     Although a few exemplary embodiments of the present disclosure have been shown and described, the present disclosure is not limited to the described exemplary embodiments. Instead, it would be appreciated by those skilled in the art that changes may be made to these exemplary embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.