Abstract:
Provided is an LED light source including a frame having a V-shaped groove formed in the upper portion thereof and a heat sink formed to extend from the lower portion thereof, the V-shaped groove having a planar bottom surface on which a circuit pattern is formed; a plurality of LEDs disposed on the bottom surface of the V-shaped groove; a diffuser plate coupled to the upper end of the frame so as to diffuse light emitted from the plurality of LEDs; a pair of plugs coupled to both side ends of the frame and receiving alternating-current (AC) power from outside; and a power converter fixed and coupled to the lower portion of the frame and electrically connected to the plugs and the plurality of LEDs, the power converter converting the AC power applied from the plugs into direct-current (DC) power and supplying the DC power to the LEDs.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of Korean Patent Application No. 10-2006-0125602 filed with the Korea Intellectual Property Office on Dec. 11, 2006, the disclosure of which is incorporated herein by reference. 
       BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates to a light emitting diode (LED) light source. 
         [0004]    2. Description of the Related Art 
         [0005]    In general, light sources are referred to as heavenly bodies, such as the sun which emit lights for itself and the moon which emits light by reflecting the solar light, and light emitting devices such as electric lamps, neon signs, and LEDs which are manufactured to emit light. 
         [0006]    Among the light sources, the LEDs are frequently used as display lamps and light sources of vehicles or home electronic appliances for a daily life. In the early stage, most of LEDs have been manufactured as low-luminance products. With the development of raw materials of LEDs and manufacturing technology, high-luminance LEDs are being manufactured so as to emit light which can represent all colors including white within the visible-light region. The high-luminance LEDs are applied to large-sized LED electric signs, exit lamps, traffic lights, various display lights of vehicles, which emit various colors of light with high luminance and high efficiency. 
         [0007]    Hereinafter, a conventional light source will be described with reference to accompanying drawings. 
         [0008]      FIG. 1  is a perspective view of a conventional light source. 
         [0009]    As shown in  FIG. 1  the conventional light source includes a pair of plugs  10 , a plurality of terminals  20 , a pair of LEDs  30 , and a transparent rod  40 . 
         [0010]    Each of the plug  10  has two terminals  20  formed to project from one end thereof and is coupled to an end of the transparent rod  40 . Further, the plug  10  includes a circuit board (not shown) having a plurality of electronic components mounted therein and supplies direct-current (DC) power, supplied through the terminals  20 , to the LED  30 . 
         [0011]    The terminals  20  are connected to the outside so as to receive DC power. 
         [0012]    The LED  30  is coupled to the plug  10  and is mounted in the transparent rod  40 . The LED  30  receives DC power supplied through the terminals  20  so as to emit light. 
         [0013]    Both ends of the transparent rod  40  are coupled to the plugs  10 , and the LEDs  30  connected to the plugs  10  are mounted in the transparent rod  40 . The transparent rod  40  is formed of a circular or rectangular transparent injection-molded rod member, and the surface thereof is surface-treated with a spreading agent or dispersing agent. 
         [0014]    When DC power is supplied through the terminals  20  of each plug  10 , the LEDs  30  receive the DC power so as to emit light to the outside through the transparent rod  40 . In this way, the conventional light source can be used as illumination. 
         [0015]    In the conventional light source, however, the light emitted from the LEDs  30  is indirectly projected through the transparent rod  40 . Therefore, an intensity of illumination required for a daily life cannot be secured. Further, as most of electric energy supplied to the LED  30  is converted into thermal energy so as to be lost, light efficiency is reduced, and surrounding equipments are deteriorated. 
         [0016]    Further, the conventional light source should be additionally provided with a separate power converter for converting AC power into DC power, in order to receive DC power supplied to the LED  30 . 
       SUMMARY OF THE INVENTION 
       [0017]    An advantage of the present invention is that it provides an LED light source which has a power converter provided therein, directly receives AC power from outside to convert into DC power, and then supplies the DC power to LEDs, thereby enhancing efficiency. Further, the LED light source has a heat sink integrally formed therein, thereby enhancing thermal efficiency. 
         [0018]    Additional aspects and advantages of the present general inventive concept will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the general inventive concept. 
         [0019]    According to an aspect of the invention, an LED light source comprises a frame having a V-shaped groove formed in the upper portion thereof and a heat sink formed to extend from the lower portion thereof, the V-shaped groove having a planar bottom surface on which a circuit pattern is formed; a plurality of LEDs disposed on the bottom surface of the V-shaped groove; a diffuser plate coupled to the upper end of the frame so as to diffuse light emitted from the plurality of LEDs; a pair of plugs coupled to both side ends of the frame and receiving alternating-current (AC) power from outside; and a power converter fixed and coupled to the lower portion of the frame and electrically connected to the plugs and the plurality of LEDs, the power converter converting the AC power applied from the plugs into direct-current (DC) power and supplying the DC power to the LEDs. 
         [0020]    Preferably, the V-shaped groove of the frame has both side walls formed of reflecting surfaces, and the V-shaped groove of the frame has both side walls formed of inclined surfaces between which the width decreases toward the lower portion. 
         [0021]    Preferably, the heat sink is not formed on the lower portion of the frame to which the power converter is coupled, the frame is formed integrally with or separately from the heat sink, and the heat sink of the frame has a plurality of heat sink pieces formed at even intervals. 
         [0022]    Preferably, the diffuser plate is any one selected from a transparent plate or a fluorescent plate containing a fluorescent material, and the LEDs are one or more LED selected from a white LED, a blue LED, an ultraviolet (UV) LED, an RGB LED, and a single-color LED. 
         [0023]    When the LED is the white LED, a transparent plate is used as the diffuser plate. When the LED is the blue LED or the UV LED, a fluorescent plate is used as the diffuser plate. When the LED is the RGB LED or the single-color LED, a transparent plate is used as the diffuser plate. 
         [0024]    Preferably, the LEDs are simultaneously driven. When the LED is the RGB LED, R, G, and B LEDs of the RGB LED are separately driven. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0025]    These and/or other aspects and advantages of the present general inventive concept will become apparent and more readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which: 
           [0026]      FIG. 1  is a perspective view of a conventional light source; 
           [0027]      FIG. 2  is an exploded perspective view of an LED light source according to the invention; 
           [0028]      FIG. 3  is an assembled perspective view of the LED light source according to the invention; 
           [0029]      FIG. 4  is a cross-sectional view of the LED light source according to the invention; and 
           [0030]      FIG. 5  is a bottom view of the LED light source according to the invention. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0031]    Reference will now be made in detail to the embodiments of the present general inventive concept, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout. The embodiments are described below in order to explain the present general inventive concept by referring to the figures. 
         [0032]    Hereinafter, an LED light source according to the present invention will be described in detail with reference to the accompanying drawings. 
         [0033]      FIG. 2  is an exploded perspective view of an LED light source according to the invention.  FIG. 3  is an assembled perspective view of the LED light source according to the invention.  FIG. 4  is a cross-sectional view of the LED light source according to the invention. 
         [0034]      FIG. 5  is a bottom view of the LED light source according to the invention. 
         [0035]    As shown in  FIG. 2 , the LED light source includes a pair of plugs  110 , a frame  130 , a plurality of LEDs  140 , a diffuser plate  150 , and a power converter  160 . 
         [0036]    Each of the plugs  10  has one surface coupled to an end of the frame  130  and has more than two terminals  120  projecting from the other surface thereof. The terminals  120  projecting from the other surface of the plug  110  are connected to an external outlet or power supply such as a transformer so as to receive AC power supplied therefrom. 
         [0037]    Both ends of the frame  30  are coupled to the plugs  110  having the terminals  120  projecting on the other surface thereof, respectively. Further, the frame  30  has a V-shaped groove  135  formed in the upper portion thereof, and a predetermined circuit (not shown) is printed on the bottom surface of the V-shaped groove  135 . 
         [0038]    Further, as shown in  FIG. 4 , the frame  130  has a heat sink  131  formed on the lower surface thereof, the heat sink  131  serving to radiate heat generated when the LEDs  140  emit light. The heat sink  131  is composed of a plurality of heat sink pieces  131   a  formed at even intervals in the lower direction of the frame  130 . The plurality of heat sink pieces  131   a  widen a contact area with the air such that the heat generated from the LEDs  140  can be quickly radiated. 
         [0039]    Meanwhile, the heat sink  131  composed of the plurality of heat sink pieces  131   a  may be formed integrally with or separately from the frame  130 . When the heat sink  131  is formed integrally with the frame  130 , an adhesive used for the coupling is not necessary, and the heat radiating property thereof is enhanced. 
         [0040]    The frame  130  may be formed of metal such as copper or aluminum with a high heat radiating property. When precision is required so as not to be affected by thermal deformation, the frame  130  may be formed of ceramic such as alumina or alumina nitride. When precision is not required or a manufacturing cost needs to be reduced by slightly decreasing a heat radiating property, the frame  130  may be formed of plastic with excellent heat conductivity. 
         [0041]    The frame  130  has an outer groove  134  formed on either outer side surface thereof in the direction where the V-shaped groove is formed. The outer groove  134  widens a contact area with the air so as to radiate the heat generated by the LEDs  140  as quickly as possible. Since the outer groove  134  is formed by removing a portion of the side surface of the frame  130 , the manufacturing cost can be reduced. 
         [0042]    Both side surfaces of the V-shaped groove  135  of the frame  130  are inclined at a predetermined angle such that the width between the side surfaces decreases toward the bottom surface. Each of the inclined surfaces serves as a reflecting surface  132  for reflecting light emitted from the LEDs  140 . 
         [0043]    The reflecting surface  132  of the frame  130  reflects light emitted from the LEDs  140  such that the light is not lost into the side surface or rear surface. Then, the light is directed to the front surface, which makes it possible to enhance light efficiency. 
         [0044]    The frame  130  has a diffuser-plate fixing groove  133  formed in the upper end thereof, that is, the upper end of the V-shaped groove  135 , the diffuser-plate fixing groove  133  having a width corresponding to the thickness of the diffuser plate  150 . The diffuser plate  150  is fixed and coupled to the diffuser-plate fixing groove  133 . 
         [0045]    The LED light source constructed in such a manner can quickly cool down the heat generated from the LEDs  140  by using the heat sink  131  formed in the frame  130 . Therefore, it is possible to prevent a reduction in lifespan of the LEDs  140 , which is caused by the heat. Further, surrounding equipments are prevented from being degraded by the heat. 
         [0046]    Further, the light emitted from the LEDs  140  is reflected by the V-shaped groove  135  so as not to be absorbed or lost into the side or rear surface. Therefore, the light efficiency can be enhanced. 
         [0047]    The plurality of LEDs  140  are disposed in line on the bottom surface of the V-shaped groove  135  of the frame  130  and are connected to the circuit printed on the bottom surface of the V-shaped groove  135 . The LEDs  140  receives power applied through the circuit so as to emit light. 
         [0048]    The diffuser plate  150  is coupled to the upper end of the frame  130  so as to diffuse the light emitted from the LEDs  140 . The diffuser plate  150  may be formed of any one selected from a transparent plate for transmitting the light emitted from the LEDs  140  and a fluorescent plate containing a fluorescent material for representing the color of the light emitted from the LEDs  140 . 
         [0049]    The plurality of LEDs  140  may be combined in various manners. That is, one or more LEDs selected from a white LED, a blue LED, an ultraviolet (UV) LED, an RGB LED, and a single-color LED may be combined. Depending on the selected LED  140 , any one of the transparent plate and the fluorescent plate can be selected as the diffuser plate  150 , thereby representing various effects desired by a user. 
         [0050]    For example, when the white LED is selected as the LED  140 , and if the transparent plate is selected as the diffuser plate  150 , the LED light source has a correlated color temperature (CCT) of 2000-8000K (absolute temperature) due to the white LED and the transparent plate. Then, it is possible to obtain light efficiency which is the same as or more excellent than that of a general fluorescent lamp (4500-6500K). Therefore, the LED light source can be used as white illumination. 
         [0051]    When the blue LED is selected as the LED  140 , the fluorescent plate is selected as the diffuser plate  150 . Then, the LED light source has the same CCT of 2000-8000K as that of the combination of the white LED and the transparent plate. Therefore, the LED light source can be used as white illumination. 
         [0052]    When the UV LED is selected as the LED  140 , the fluorescent plate is selected as the diffuser plate  150 . When the RGB LED or single-color LED is selected as the LED  140 , the transparent plate is selected as the diffuser plate  150 . Then, the LED light source has a CCT of 2000-8000K and can be used as white illumination. 
         [0053]    Meanwhile, when the RGB LED is selected as the LED  140 , R (red), G (green), and B (blue) LEDs which respectively represent their own colors can be controlled to be simultaneously or separately driven. When they are simultaneously driven, the LED light source may be used as white illumination. Alternately, when they are separately driven, the LED light source may emit only the respective colors of light or various colors of light desired by a user, as the tone of the colors is separately adjusted. 
         [0054]    When only red light is desired to be emitted, power is supplied to only the R LED of the RGB LED. When only blue light is desired to be emitted, power is supplied to only the B LED of the RGB LED. 
         [0055]    Further, as power is supplied to R and B LEDs, respectively, purple light can be emitted. As an amount of current supplied to each of the R, G, and B LEDs is adjusted, a color and brightness desired by a user can be represented. 
         [0056]    The power converter  160  is coupled to the lower portion of the frame  130  and is connected to the plugs  110  and the printed circuit of the frame  130 . In this case, the heat sink  131  is not formed on the lower portion of the frame  130  coupled to the power converter  160 , as shown in  FIG. 5 , but the power converter  160  is directly coupled to the lower portion of the frame  130  so as to be connected to the printed circuit formed on the bottom surface of the V-shaped groove  135  of the frame  130 . 
         [0057]    The power converter  160  receives AC power applied from outside through the terminals  120  of the plug  110  and converts the AC power into DC power for driving the LEDs  140  to supply to the LEDs  140 . In this case, it is possible to solve the problem of the conventional LED light source which should be additionally provided with a separate large-volume power converter for driving the LEDs. Further, the LED light source can be reduced in size. Therefore, as only a commercial voltage of 110V or 220V is supplied, the LED light source can be utilized anywhere. 
         [0058]    According to the LED light source of the present invention, the LED light source has the power converter provided on the lower portion thereof. Therefore, the LED light source directly receives AC power from outside to convert into DC power, and then supplies the DC power to the LEDs. Accordingly, the LED light source can be effectively utilized. 
         [0059]    Further, the heat sink for radiating the heat generated from the LEDs is formed integrally with the frame, thereby enhancing the thermal efficiency. Therefore, it is possible to prevent the reduction in lifespan of the LEDs and the degradation of surrounding equipments. 
         [0060]    Furthermore, the LEDs selected from a white LED, a blue LED, an ultraviolet (UV) LED, an RGB LED, and a single-color LED may be used. Therefore, the LED light source can emit various colors of light desired by a user. 
         [0061]    Although a few embodiments of the present general inventive concept have been shown and described, it will be appreciated by those skilled in the art that changes may be made in these embodiments without departing from the principles and spirit of the general inventive concept, the scope of which is defined in the appended claims and their equivalents.