Patent Publication Number: US-2022231077-A1

Title: Led package set and led bulb including same

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This is a Continuation of U.S. patent application Ser. No. 16/618,004, filed on Nov. 27, 2019, which is a National Stage Entry of International Application No. PCT/KR2018/006137, filed on May 30, 2018, and claims priority from and the benefit of Korean Patent Application No. 10-2017-0067992, filed on May 31, 2017, each of which is hereby incorporated by reference for all purposes as if fully set forth herein. 
    
    
     BACKGROUND 
     Field 
     Exemplary embodiments of the invention relate generally to an LED package set and an LED bulb including the same. 
     Discussion of the Background 
     Conventionally, incandescent lamps using filaments have been widely used as luminaires. A filament-based incandescent lamp generally emits light by temperature radiation, which may occur when a tungsten filament is heated in a vacuum glass bulb to high temperature through application of electricity. 
     Such a typical incandescent lamp is not suitable for long-term use due to short lifespan of the filament and extremely low energy efficiency, since most of energy supplied thereto is released as heat and only a fraction of the energy is converted into light. 
     Recently, light emitting diodes (LEDs) having long lifespan and high energy efficiency are used in luminaires. 
     The above information disclosed in this Background section is only for understanding of the background of the inventive concepts, and, therefore, it may contain information that does not constitute prior art. 
     SUMMARY 
     LED packages and LED bulbs including the same constructed according to exemplary embodiments of the invention are capable of providing high economic efficiency due to long lifespan and low heat generation. 
     Exemplary embodiments also provide an LED package set, which allows regulation of color temperature of light emitted therefrom, and an LED bulb including the same. 
     Exemplary embodiments further provide an LED package set, which can evenly emit light in all directions by emitting light in different directions, and an LED bulb including the same. 
     Additional features of the inventive concepts will be set forth in the description is which follows, and in part will be apparent from the description, or may be learned by practice of the inventive concepts. 
     An LED package set according to an exemplary embodiment includes a substrate, a first LED package disposed on the substrate and including at least one first LED chip, a second LED package disposed on the substrate and including at least one second LED chip, and a resistor disposed on the substrate, connected to the first LED package in series, and connected to the second LED package in parallel, in which the second LED package is connected in parallel to the first LED package and the resistor, and the first LED package and the second LED package are configured to emit light having different color temperatures. 
     The substrate may include a pair of electrode pads, each of the first LED package, second LED package, and the resistor may include a first end and a second end opposing the first end, the first end of the first LED package and the first end of the second LED package may be connected to one of the pair of electrode pads, the first end of the resistor may be connected to the second end of the first LED package, and the second end of the second LED package and the second end of the resistor may be connected to the other one of the pair of electrode pads. 
     Light from the first LED package may have a higher color temperature than light from the second LED package. 
     A difference in color temperature between light from the first LED package and light from the second LED package may be at least 500 K. 
     A difference in color temperature between light from the first LED package and light from the second LED package may be less than or equal to 1,000 K. 
     Current may be distributed to the first LED package and the second LED package depending a resistance formed by the first LED package and the resistor connected in series, and is a resistance of the second LED package. 
     A color temperature of a mixture of light from the first LED package and the second LED package may change depending on current flowing through the first LED package and current flowing through the second LED package. 
     The first LED package may include a first wavelength conversion portion covering the at least one first LED chip, and the second LED package may include a second wavelength conversion portion covering the at least one second LED chip. 
     The first LED chip and the second LED chip may be configured to emit light having the same color temperature. 
     The first wavelength conversion portion and the second wavelength conversion portion may include phosphors having different color temperatures, respectively. 
     The LED package set may further include a wavelength conversion portion covering each the first LED chip and the second LED chip. 
     The first LED chip and the second LED chip may be configured to emit light having different color temperatures. 
     An LED bulb according to another exemplary embodiment includes a base including an external electrode pad to receive electricity from an external power supply, an LED package set including a substrate that includes a pair of electrode pads disposed at one end thereof, a first LED package including at least one first LED chip, a second LED package including at least one second LED chip, and a resistor, a holder including a connection portion to receive one end of the LED package set, and electrically connected to the pair of electrode pads of the substrate, and a light transmissive cover enclosing the LED package set and coupled to the base, in which the first LED package, the second LED package, and the resistor are disposed on is the substrate, the first LED package and the second LED package are connected in parallel, and are configured to emit light having different color temperatures, and the resistor is connected to the first LED package in series and connected to the second LED package in parallel. 
     Each of the first LED package, second LED package, and the resistor may include a first end and a second end opposing the first end, the first end of the first LED package and the first end of the second LED package may be connected to one of the pair of electrode pads, the second end of the resistor may be connected to the second end of the first LED package, and the second end of the second LED package and the second end of the resistor may be connected to the other one of the pair of electrode pads. 
     Light from the first LED package may have a higher color temperature than light from the second LED package. 
     A difference in color temperature between light from the first LED package and light from the second LED package may be in a range of 500 K to 1,000 K. 
     The connection portion of the holder may include a groove or hole, to which one end of the substrate is inserted, and the connection portion may include a pair of connection terminals electrically connected to the pair of electrode pads of the substrate. 
     The substrate may further include a bent portion disposed between the pair of electrode pads and the first LED chip, the second LED chip, and the resistor, by which the substrate is bent in an upwards or downwards direction. 
     The first LED package may include a first wavelength conversion portion covering the first LED chip, the second LED package may include a second wavelength conversion portion covering the second LED chip, the first LED chip and the second LED chip may be configured to emit light having the same color temperature, and the first wavelength conversion portion and the second wavelength conversion portion may include phosphors having different color temperatures, respectively. 
     The LED bulb may further include a wavelength conversion portion covering each of the first LED chip and the second LED chip, in which the first wavelength conversion portion and the second wavelength conversion portion may include phosphors having different color temperatures, respectively. 
     It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate exemplary embodiments of the invention, and together with the description serve to explain the inventive concepts. 
         FIG. 1  and  FIG. 2  are views of an LED package set according an exemplary embodiment. 
         FIG. 3  is a circuit diagram of the LED package set according to an exemplary embodiment. 
         FIG. 4  and  FIG. 5  are views of an LED bulb according to another exemplary embodiment. 
         FIG. 6  is a view of an LED bulb according to still another exemplary embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     In the following description, for the purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of various exemplary embodiments or implementations of the invention. As used herein “embodiments” and “implementations” are interchangeable words that are non-limiting examples of devices or methods employing one or more of the inventive concepts disclosed herein. It is apparent, however, that various exemplary embodiments may be practiced without these specific details or with one or more equivalent arrangements. In other instances, well-known structures and devices are shown in block diagram form in order to avoid unnecessarily obscuring various exemplary embodiments. Further, various exemplary embodiments may be different, but do not have to be exclusive. For example, specific shapes, configurations, and characteristics of an exemplary embodiment may be used or implemented in another exemplary embodiment without departing from the inventive concepts. 
     Unless otherwise specified, the illustrated exemplary embodiments are to be understood as providing exemplary features of varying detail of some ways in which the inventive concepts may be implemented in practice. Therefore, unless otherwise specified, the features, components, modules, layers, films, panels, regions, and/or aspects, etc. (hereinafter individually or collectively referred to as “elements”), of the various embodiments may be otherwise combined, separated, interchanged, and/or rearranged without departing from the inventive concepts. 
     The use of cross-hatching and/or shading in the accompanying drawings is generally provided to clarify boundaries between adjacent elements. As such, neither the is presence nor the absence of cross-hatching or shading conveys or indicates any preference or requirement for particular materials, material properties, dimensions, proportions, commonalities between illustrated elements, and/or any other characteristic, attribute, property, etc., of the elements, unless specified. Further, in the accompanying drawings, the size and relative sizes of elements may be exaggerated for clarity and/or descriptive purposes. When an exemplary embodiment may be implemented differently, a specific process order may be performed differently from the described order. For example, two consecutively described processes may be performed substantially at the same time or performed in an order opposite to the described order. Also, like reference numerals denote like elements. 
     When an element, such as a layer, is referred to as being “on,” “connected to,” or “coupled to” another element or layer, it may be directly on, connected to, or coupled to the other element or layer or intervening elements or layers may be present. When, however, an element or layer is referred to as being “directly on,” “directly connected to,” or “directly coupled to” another element or layer, there are no intervening elements or layers present. To this end, the term “connected” may refer to physical, electrical, and/or fluid connection, with or without intervening elements. Further, the D1-axis, the D2-axis, and the D3-axis are not limited to three axes of a rectangular coordinate system, such as the x, y, and z-axes, and may be interpreted in a broader sense. For example, the D1-axis, the D2-axis, and the D3-axis may be perpendicular to one another, or may represent different directions that are not perpendicular to one another. For the purposes of this disclosure, “at least one of X, Y, and Z” and “at least one selected from the group consisting of X, Y, and Z” may be construed as X only, Y only, Z only, or any combination of two or more of X, Y, and Z, such as, for instance, XYZ, XYY, YZ, and ZZ. As used herein, the term “and/or” includes any and all combinations of one or more of the is associated listed items. 
     Although the terms “first,” “second,” etc. may be used herein to describe various types of elements, these elements should not be limited by these terms. These terms are used to distinguish one element from another element. Thus, a first element discussed below could be termed a second element without departing from the teachings of the disclosure. 
     Spatially relative terms, such as “beneath,” “below,” “under,” “lower,” “above,” “upper,” “over,” “higher,” “side” (e.g., as in “sidewall”), and the like, may be used herein for descriptive purposes, and, thereby, to describe one elements relationship to another element(s) as illustrated in the drawings. Spatially relative terms are intended to encompass different orientations of an apparatus in use, operation, and/or manufacture in addition to the orientation depicted in the drawings. For example, if the apparatus in the drawings is turned over, elements described as “below” or “beneath” other elements or features would then be oriented “above” the other elements or features. Thus, the exemplary term “below” can encompass both an orientation of above and below. Furthermore, the apparatus may be otherwise oriented (e.g., rotated 90 degrees or at other orientations), and, as such, the spatially relative descriptors used herein interpreted accordingly. 
     The terminology used herein is for the purpose of describing particular embodiments and is not intended to be limiting. As used herein, the singular forms, “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. Moreover, the terms “comprises,” “comprising,” “includes,” and/or “including,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, components, and/or groups thereof, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or is groups thereof. It is also noted that, as used herein, the terms “substantially,” “about,” and other similar terms, are used as terms of approximation and not as terms of degree, and, as such, are utilized to account for inherent deviations in measured, calculated, and/or provided values that would be recognized by one of ordinary skill in the art. 
     As customary in the field, some exemplary embodiments are described and illustrated in the accompanying drawings in terms of functional blocks, units, and/or modules. Those skilled in the art will appreciate that these blocks, units, and/or modules are physically implemented by electronic (or optical) circuits, such as logic circuits, discrete components, microprocessors, hard-wired circuits, memory elements, wiring connections, and the like, which may be formed using semiconductor-based fabrication techniques or other manufacturing technologies. In the case of the blocks, units, and/or modules being implemented by microprocessors or other similar hardware, they may be programmed and controlled using software (e.g., microcode) to perform various functions discussed herein and may optionally be driven by firmware and/or software. It is also contemplated that each block, unit, and/or module may be implemented by dedicated hardware, or as a combination of dedicated hardware to perform some functions and a processor (e.g., one or more programmed microprocessors and associated circuitry) to perform other functions. Also, each block, unit, and/or module of some exemplary embodiments may be physically separated into two or more interacting and discrete blocks, units, and/or modules without departing from the scope of the inventive concepts. Further, the blocks, units, and/or modules of some exemplary embodiments may be physically combined into more complex blocks, units, and/or modules without departing from the scope of the inventive concepts. 
     Unless otherwise defined, all terms (including technical and scientific terms) used is herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure is a part. Terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and should not be interpreted in an idealized or overly formal sense, unless expressly so defined herein. 
       FIG. 1  and  FIG. 2  are views of an LED package set according to an exemplary embodiment. 
     In particular,  FIG. 1  is a plan view of an LED package set  100  according to an exemplary embodiment, and  FIG. 2  is a cross-sectional view taken along line A 1 -A 2  of the LED package set  100  of  FIG. 1 . 
     Referring to  FIG. 1  and  FIG. 2 , the LED package set  100  includes a substrate  140 , a first LED package  110 , a second LED package  120 , and a resistor  130 . The LED package set  100  may be driven in a constant current mode. 
     The substrate  140  is a circuit substrate having a wiring circuit formed thereon. For example, the substrate  140  may be any substrate suitable for forming a wiring circuit thereon, such as a printed circuit board, a metal substrate, and a glass substrate. In some exemplary embodiments, the substrate  140  may be a metal substrate having high heat dissipation performance, which may allow a plurality of LED chips or LED packages to be disposed thereon. 
     The substrate  140  includes a pair of electrode pads  141  formed at one end thereof. The pair of electrode pads  141  receives electricity for driving the first LED package  110  and the second LED package  120  from the outside of the LED package set  100 . In this case, electricity applied to the substrate  140  may be changed according to a dimming signal. 
     The pair of electrode pads  141  formed on the substrate  140  is electrically connected to the first LED package  110 , the second LED package  120 , and the resistor  130 . 
     The first LED package  110  is disposed on the substrate  140 . The first LED package  110  includes a first LED chip  111  and a first wavelength conversion portion  115 . 
     The first LED package  110  may include at least one first LED chip  111 . In this case, the first LED chips  111  of the first LED package  110  may be electrically connected to one another and form an array. 
     The first wavelength conversion portion  115  is formed on the substrate  140  and cover the first LED chip  111 . The first wavelength conversion portion  115  may be formed to collectively cover multiple first LED chips  111 . Alternatively, the first wavelength conversion portion  115  may be formed to individually cover each of the first LED chips  111 . 
     The second LED package  120  is disposed on the substrate  140 . The second LED package  120  includes a second LED chip  121  and a second wavelength conversion portion  125 . 
     The second LED package  120  may include at least one second LED chip  121 . When the second LED package  120  includes multiple second LED chips  121 , the second LED chips  121  may be electrically connected to one another and form an array. 
     The second wavelength conversion portion  125  is formed on the substrate  140  and cover the second LED chip  121 . The second wavelength conversion portion  125  may be formed to collectively cover multiple second LED chips  121 . Alternatively, the second wavelength conversion portion  125  may be formed to individually cover each of the second LED chips  121 . 
     The first LED package  110  and the second LED package  120  emit light of the same color. In addition, light from the first LED package  110  has a different color temperature than light from the second LED package  120 . For example, the first LED package  110  and the second LED package  120  may emit white light having different color temperatures. 
     Light emitted from the first LED chip  111  and the second LED chip  121  is warm light. For example, light emitted from the first LED chip  111  and the second LED chip  121  has a color temperature of 1,000 K to 4,000 K. In some exemplary embodiments, light emitted from the first LED chip  111  and the second LED chip  121  has a color temperature of 1,600 K to 3,000 K. 
     In addition, the first wavelength conversion portion  115  and the second wavelength conversion portion  125  include different phosphors. Thus, light emitted from the first LED package  110  through the first wavelength conversion portion  115  has a different color temperature than light emitted from the second LED package  120  through the second wavelength conversion portion  125 . 
     According to an exemplary embodiment, the first wavelength conversion portion  115  includes a phosphor having a higher color temperature. For example, the first wavelength conversion portion  115  may include a phosphor having a color temperature of about 3,000 K. In addition, the second wavelength conversion portion  125  includes a phosphor having a lower color temperature. For example, the second wavelength conversion portion  125  may include a phosphor having a color temperature of about 1,800 K. 
     Accordingly, light from the first LED package  110  has a higher color temperature than light from the second LED package  120 . However, the inventive concepts are not limited thereto. For example, in an LED package according to another exemplary embodiment, light from the second LED package  120  has a higher color temperature than light from the first LED package  110 , when light from the first LED package  110  and light from the second LED package  120  has a different color temperature from each other. 
     A difference in color temperature between light from the first LED package  110  and light from the second LED package  120  may range from 500 K to 1,000 K. 
     An LED package having a lower color temperature may have a lower light intensity than an LED package having a higher color temperature. Thus, in order to supplement light intensity of the second LED package  120  having a lower color temperature, the second LED chip  121  may have a wider light emitting area than the first LED chip  111 . In particular, the second LED chip  121  may be larger than the first LED chip  111 . 
     The resistor  130  may be disposed on the substrate  140  or embedded in the substrate  140 . The resistor  130  may have a fixed resistance. The resistor  130  is adapted to distribute current to the first LED package  110  and the second LED package  120 . 
     Although a wiring circuit is not shown in  FIG. 1 , the first LED package  110  is connected in series to the resistor  130 . Further, the second LED package  120  is connected in parallel to the first LED package  110  and the resistor  130 , which are connected in series. 
     The LED package set  100  according to the illustrated exemplary embodiment emits a mixture of light having different color temperatures. 
     Voltage changed in magnitude according to an external dimming signal is applied to the LED package set  100 . A resistance ratio of the first LED package  110  to the second LED package  120  is changed depending on the change in voltage and the resistor  130 . 
     Current is distributed to the first LED package  110  and the second LED package  120  in accordance to an inverse relationship to the resistance ratio. 
     As used herein, the dimming signal may refer to a signal that controls the magnitude of electricity applied to the substrate  140  to regulate color temperature of light emitted from the LED package set  100 . 
     As current flowing through the first LED package  110  and the second LED package  120  is changed, the strength or brightness of light emitted from each of the first LED package  110  and the second LED package  120  is changed. Accordingly, a color temperature of mixed light from the LED package set  100  is regulated by the change in strength or brightness ratio between light from the first LED package  110  and light from the second LED package  120  having different color temperatures. 
     In the illustrated exemplary embodiment, the first LED package  110  and the second LED package  120  are described as including the first wavelength conversion portion  115  and the second wavelength conversion portion  125 , respectively. However, the inventive concepts are not limited thereto. For example, in some exemplary embodiments, the first wavelength conversion portion  115  and the second wavelength conversion portion  125  may be omitted, when each of the first LED chip  111  and the second LED chip  121  emits light having a color and color temperature desired by a user. 
     In addition, the LED package set  100  according to the illustrated exemplary embodiment is described as including two LED packages emitting light having different color temperatures. However, the inventive concepts are not limited thereto. For example, in some exemplary embodiments, the LED package set  100  may include three or more LED packages emitting light having different color temperatures. In this case, the color temperature of light emitted from the LED package set  100  can be more accurately regulated by adjusting the resistance of resistors connected in series to the LED packages. 
     According to another exemplary embodiment, the first LED chip  111  of the first LED package  110  and the second LED chip  121  of the second LED package  120  may emit light having different color temperatures. In this case, the first LED package  110  and the second LED is package  120  may be covered by a single common wavelength conversion portion. 
     According to still another exemplary embodiment, the first LED chip  111  of the first LED package  110  and the second LED chip  121  of the second LED package  120  may emit light having the same color temperature. More particularly, the first LED chip  111  may be the same as the second LED chip  121 . In this case, the first wavelength conversion portion  115  of the first LED package  110  and the second wavelength conversion portion  125  of the second LED package  120  may include phosphors having different color temperatures, respectively. 
       FIG. 3  is a circuit diagram of an LED package set according to an exemplary embodiment. 
     An LED package set  100  represented by the circuit of  FIG. 3  is the LED package set  100  of  FIG. 1  and  FIG. 2 . 
     Referring to  FIG. 3 , a first LED array  113  of the first LED package ( 110  of  FIG. 1 ) is connected in series to the resistor  130 . Here, one end of the resistor  130  is connected to a cathode of the first LED array  113 , in particular, the other end of the first LED array. In addition, a second LED array  123  of the second LED package ( 120  of  FIG. 2 ) is connected in parallel to the first LED array  113  and the resistor  130 , which are connected in series. An anode of the first LED array  113  and an anode of the second LED array  123  are connected to a first terminal  151 . In addition, the other end of the resistor  130  and a cathode of the second LED array  123  are connected to a second terminal  152 . The first terminal  151  and the second terminal  152  are connected to opposite ends of a constant current system  160 , respectively. The resistor  130  has a predetermined fixed resistance. As used herein, the constant current system  160  is a system that supplies electricity to the LED package set  100  in a constant current mode. 
     Electricity applied to the LED package set  100  is changed according to an is external dimming signal. More particularly, voltage and current applied to the LED package set  100  are changed according to the external dimming signal. As voltage applied to the LED package set  110  is changed according to the dimming signal, a ratio between a resistance formed by the first LED package  110  and the resistor  130 , and a resistance by the second LED package  120  is changed. Current from the constant current system  160  is distributed to the first LED package  110  and the second LED package  120  in inverse relationship to the ratio. 
     Hereinafter, the following example will be described with an assumption that the dimming signal indicates a dimming level of 100% when the light intensities of the first LED package ( 110  of  FIG. 1 ) and the second LED package ( 120  of  FIG. 2 ) reach the same maximum values, and that current applied to the LED package set has a maximum value of 30 mA. 
     In this example, the first LED package ( 110  of  FIG. 1 ) has a color temperature of 3,000 K and the second LED package ( 120  of  FIG. 2 ) has a color temperature of 1,800 K. Further, the resistor  130  has a resistance of 1 kQ. 
     At a dimming level of 10%, a current of 3 mA is applied to the first terminal  151 . In this case, all of the current flows through the second LED package ( 120  of  FIG. 2 ). Thus, the first LED package ( 110  of  FIG. 1 ) is in an OFF state. The second LED package ( 120 ,  FIG. 2 ) emits light having an intensity corresponding to 3 mA. Since only the second LED package ( 120  of  FIG. 2 ) emits light, light from the LED package set  100  has a color temperature of 1,800 K. 
     At a dimming level of 20%, a current of 6 mA is applied to the first terminal  151 . In this case, a current of 1.2 mA flows through the first LED package ( 110  of  FIG. 1 ) and a current of 4.8 mA flows through the second LED package ( 120  of  FIG. 2 ). As a result, the LED package set  100  emits light having a color temperature of 2,100 K. 
     At a dimming level of 50%, a current of 15 mA is applied to the first terminal  151 . In this case, a current of 4.5 mA flows through the first LED package ( 110  of  FIG. 1 ) and a current of 10.5 mA flows through the second LED package ( 120  of  FIG. 2 ). As a result, the LED package set  100  emits light having a color temperature of 2,400 K. 
     At a dimming level of 75%, a current of 22.5 mA is applied to the first terminal  151 . In this case, a current of 9 mA flows through the first LED package ( 110  of  FIG. 1 ) and a current of 13.5 mA flows through the second LED package ( 120  of  FIG. 2 ). As a result, the LED package set  100  emits light having a color temperature of 2,550 K. 
     At a dimming level of 100%, a current of 30 mA is applied to the first terminal  151 . In this case, a current of 15 mA flows through each of the first LED package ( 110  of FIG.  1 ) and the second LED package ( 120  of  FIG. 2 ). As a result, the LED package set  100  emits light having a color temperature of 2,700 K. 
     In this manner, the LED package set  100  according to the illustrated exemplary embodiment can emit light having various color temperatures by distributing current to the first LED package ( 110  of  FIG. 1 ) and the second LED package ( 120  of  FIG. 2 ) according to the dimming signal. 
       FIG. 4  and  FIG. 5  are exemplary views of an LED bulb according to another exemplary embodiment. 
       FIG. 4  is an exemplary view of a base  170  and a holder  180  of an LED bulb  10 , and  FIG. 5  is an exemplary view of the LED bulb  10  with an LED package set  100  mounted on the base  170  and the holder  180  of  FIG. 4 . 
     Referring to  FIGS. 4 and 5 , the LED bulb  10  includes the base  170 , the LED package set  100 , the holder  180 , and a light transmissive cover  190 . The LED package set  100  may be the LED package set  100  described above with reference to  FIG. 1  to  FIG. 3 . 
     The base  170  is coupled to a socket for connection to an external power supply. The base  170  includes a first external electrode  171  and a second external electrode  172  formed on an outer surface thereof and electrically connected to the socket. The first external electrode  171  and the second external electrode  172  receive electricity from the external power supply. 
     The light transmissive cover  190  is coupled to the base  170  to enclose internal components, such as the holder  180  and the LED package set  100 . The light transmissive cover  190  is formed of a light transmissive material. For example, the light transmissive cover  190  is formed of glass. 
     The holder  180  and the LED package set  100  are disposed in the LED bulb  10 . An interior of the LED bulb  10  may be an inner space defined when the base  170  is coupled to the light transmissive cover  190 . 
     The holder  180  is disposed under the LED package set  100  to support the LED package set  100  in an upright position. Referring to  FIG. 4 , the holder  180  includes a connection portion  181  provided in the form of a groove or a through-hole. The connection portion  181  includes a pair of connection terminals  183  formed of a conductive material. One of the pair of connection terminals  183  is electrically connected to the first external electrode  171  of the base  170 , and the other connection terminal  183  is electrically connected to the second external electrode  172  of the base  170 . The pair of connection terminals  183  is connected to the first external electrode  171  and the second external electrode  172  of the base  170  via conductive parts, such as wires, respectively. In the illustrated exemplary embodiment, the holder  180  is being described as a separate component from the base  170 . However, the inventive concepts are not limited thereto, and in some exemplary embodiments, the holder  180  may be integrally formed with the base  170 . 
     The LED bulb  10  includes at least one LED package set  100 . In  FIG. 5 , the LED bulb  10  is shown as including four LED package sets  100 . However, the inventive concepts are not limited thereto, and the number of LED package sets  100  mounted on the LED bulb  10  may be varied as needed. 
     The LED package set  100  is secured to the holder  180 . One end of the LED package set  100  is inserted into the connection portion  181  of the holder  180 . Thus, the LED package set  100  is disposed in an upright position inside the LED bulb  10 . More particularly, the LED package set  100  may be disposed, such that the first LED package  110  and the second LED package  120  face an inner surface of the light transmissive cover  190 . 
     In addition, the one end of the LED package set  100  inserted into the connection portion  181  corresponds to one end of the substrate  140 , at which the pair of electrode pads  141  is formed. When the one end of the LED package set  100  is inserted into the connection portion  181 , the pair of connection terminals  183  of the connection portion  181  is brought into contact with and electrically connected to the pair of electrode pads  141  of the substrate  140 . Accordingly, electricity changed according to the dimming signal is applied to the LED package set  100  through the first external electrode  171  and the second external electrode  172  of the base  170  and the pair of connection terminals  183  of the holder  180 . 
     Since the LED bulb  10  has a configuration, in which the LED package set  100  is secured by being inserted into the holder  180 , the LED package set  100  may be easily replaced upon failure of the LED package set  100 . 
     According to the exemplary embodiments, the LED package set  100  allows light intensities of the first LED package  110  and the second LED package  120  to be regulated depending on current applied thereto. In particular, the color temperature of light emitted from is the LED bulb  10  is changed in accordance with the change in current applied from the outside. Thus, the LED bulb  10  can emit light having a color temperature suitable for a specific application or environment. 
     In addition, according to the exemplary embodiments, the LED package set  100  includes the resistor  130  connected in series to the first LED package  110 , and connected in parallel to the second LED package  120 . In addition, current is distributed to the first LED package  110  and the second LED package  120  depending on the resistance formed by the first LED package  110  and the resistor  130 , and the resistance of the second LED package  120 . Thus, the LED bulb  10  can emit light, in which a color temperature thereof may be changed according to the dimming signal. 
     In addition, according to the exemplary embodiments, the LED bulb  10  can evenly emit light laterally by including the plurality of LED package sets  100 . 
       FIG. 6  is an exemplary view of an LED bulb according to still another exemplary embodiment. 
     The LED bulb  20  according to the illustrated exemplary embodiment is substantially the same as the LED bulb  20  of  FIG. 5 , and thus, repeated descriptions of the substantially the same components thereof will be omitted to avoid redundancy. 
     Referring to  FIG. 6 , the LED bulb  20  according to the illustrated exemplary embodiment includes at least one LED package set  200 . The LED package set  200  is formed with a bent portion  210 . The bent portion  210  is formed on the substrate  140  between the pair of electrode pads  141  and the first LED chip  111 , the second LED chip  121 , and the resistor  130 . In addition, the bent portion  210  is formed in a transverse direction of the substrate  140 . As used herein, the transverse direction of the substrate  140  is a perpendicular direction with respect to a is straight line connecting one end of the substrate  140 , at which the pair of electrode pads  141  is formed, to the other end of the substrate  140 . 
     The bent portion  210  is provided to bend the LED package set  200  at a predetermined angle. The bent portion  210  may be formed in any shape and by any method, so long as the LED package set  200  can be bent with respect to the bent portion  210 . For example, the bent portion  210  may be formed by half-etching a portion of the substrate  140 . Alternatively, the bent portion  210  may be provided in the form of at least one through-hole formed through a portion of the substrate  140 . Still alternatively, the bent portion  210  may be provided in the form of an indentation formed by pressing a pointed object into a portion of the substrate  140 . 
     The LED package set  200  may be bent with respect to the bent portion  210 , such that the first LED package  110  and the second LED package  120  face in an upward direction of the LED bulb  20 , as shown in  FIG. 6 . 
     In this manner, the LED bulb  20  including the LED package sets  200  as shown in  FIG. 6  can evenly emit light upwards as well as laterally. 
     Alternatively, the LED bulb  20  may include an LED package set  200  bent downwards, as opposed to  FIG. 6 , to evenly emit light laterally and downwards. Still alternatively, the LED bulb  20  may include both an LED package set bent upwards and an LED package set bent downwards to evenly emit light laterally, upwards, and downwards. 
     According to exemplary embodiments, an LED package set and an LED bulb including the same can have long lifespan and low heat generation by employing an LED package, instead of a tungsten filament, thereby improving economic efficiency. 
     In addition, the LED package set and the LED bulb including the same can emit light having a suitable color temperature according to an environment by using at least two LED is packages emitting light having different color temperatures. 
     Further, the LED package set and the LED bulb including the same include a resistor connected in series to one LED package and connected in parallel to the other LED package. Thus, the LED package set and the LED bulb can emit light having a color temperature that may be changed in accordance to voltage and current supplied to the LED package set. 
     Although certain exemplary embodiments and implementations have been described herein, other embodiments and modifications will be apparent from this description. Accordingly, the inventive concepts are not limited to such embodiments, but rather to the broader scope of the appended claims and various obvious modifications and equivalent arrangements as would be apparent to a person of ordinary skill in the art.