Patent Publication Number: US-2015069432-A1

Title: Light-emitting structure

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application is a continuation-in-part of U.S. application Ser. No. 13/531,462, filed on 22 Jun. 2012 and entitled “LED PACKAGE STRUCTURE”, now pending, the entire disclosures of which are incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present disclosure relates to a light-emitting structure; in particular, to a light emitting structure which provides a color tunable LEDs device by a combination of warm white and cool white multi CSP (Chip Scale Package) LEDs. 
     2. Description of Related Art 
     Comparing light-emitting diodes to traditional light sources, the light-emitting diodes (LEDs) is small, saves electricity, has good light emission efficiency, has a long life span, is responsive, and does not produce thermal radiation, mercury or other pollutants. Therefore in recent years, application of LEDs has become more widespread. 
     SUMMARY OF THE INVENTION 
     The object of the present disclosure is to provide a light-emitting structure having warm white and cool white multi CSP (Chip Scale Package) LEDs capable of uniform mixing color. 
     According to the present disclosure, the light-emitting structure, which has at least two meandering conductive tracks on a substrate and a light-emitting unit having cool white LEDs and warm white LEDs alternately arranged and mounted on thereof. Thus, a predetermined fixed target color temperature, a fine adjustment of color temperature can be achieved. 
     In order to further the understanding regarding the present disclosure, the following embodiments are provided along with illustrations to facilitate the disclosure of the present disclosure. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows a top view of a light-emitting structure according to a first embodiment of the present disclosure; 
         FIG. 2  shows a partial side cross-sectional view of a light-emitting structure using air layer as a thermal resistant structure according to a first embodiment of the present disclosure; 
         FIG. 3  shows a partial side cross-sectional view of a light-emitting structure using a layer of material having high heat resistance as a thermal resistant structure according to a first embodiment of the present disclosure; 
         FIG. 4  shows a top view of a plurality of first LED chips and a plurality of second LED chips arranged in an approximately circular region according to a first embodiment of the present disclosure; 
         FIG. 5  shows a top view of a plurality of first LED chips and a plurality of second LED chips arranged in a circular region according to a first embodiment of the present disclosure; 
         FIG. 6  shows a schematic diagram of another method for offsetting a first LED chip onto a circular track according to a first embodiment of the present disclosure; 
         FIG. 7  shows a schematic diagram of first LED chips and second LED chips disposed in vertical paths and in an approximately circular region according to a first embodiment of the present disclosure; 
         FIG. 8  shows a top view of two independent groups of light-emitting structures according to a first embodiment of the present disclosure; 
         FIG. 9  shows a top view of two groups of light-emitting structures connected in parallel according to a first embodiment of the present disclosure; 
         FIG. 10  shows a side cross-sectional view of a light structure according to a second embodiment of the present disclosure; 
         FIG. 11  shows a side cross-sectional view of a light structure according to a third embodiment of the present disclosure; 
         FIG. 12  shows a side cross-sectional view of a light structure according to a fourth embodiment of the present disclosure; 
         FIG. 13  shows a side cross-sectional view of a light structure according to a fifth embodiment of the present disclosure; 
         FIG. 14  shows a side cross-sectional view of a light structure according to a sixth embodiment of the present disclosure; 
         FIG. 15  shows a side cross-sectional view of a light structure according to a seventh embodiment of the present disclosure; 
         FIG. 16  shows a side cross-sectional view of a light structure according to an eighth embodiment of the present disclosure; 
         FIG. 17  shows a top view including a frame gel body according to a ninth embodiment of the present disclosure; 
         FIG. 18  shows a top view of a light-emitting structure according to a ninth embodiment of the present disclosure; 
         FIG. 19  shows a top view including a frame gel body according to a tenth embodiment of the present disclosure; and 
         FIG. 20  shows a top view of a light-emitting structure according to a tenth embodiment of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     First Embodiment 
     Referring to  FIG. 1  and  FIG. 2 , a first embodiment of the present disclosure provides a light-emitting structure including a substrate  1  and a light-emitting unit  2 . 
     As shown in  FIG. 1 , the upper surface of the substrate  1  has at least one meandering first conductive track  11  and at least one meandering second conductive track  12 . The at least one first conductive track  11  has a plurality of first chip-mounting areas  110 . The at least one second conductive track  12  has a plurality of second chip-mounting areas  120 . The first chip-mounting areas  110  and the second chip-mounting areas  120  are alternately arranged. Additionally, each of the first chip-mounting areas  110  has at least two first chip-mounting lines  1100  arranged proximal to each other and in series. Each of the second chip-mounting areas  120  has at least two second chip-mounting lines  1200  arranged proximal to each other and in series. For example, as shown in  FIG. 1 , the meandering shapes of the first conductive track  11  and the second conductive track  12  are similar to an S-shaped serial connection. The meandering first conductive track  11  and the meandering second conductive track  12  are arranged close to each other in the form of interlocking fingers of two hands but without contacting each other, such that the first conductive track  11  and the second conductive track  12  present a line design of alternate arrangement. Additionally, the plurality of first chip-mounting lines  1100  and the plurality of second chip-mounting lines  1200  can be parallel to each other, but the present disclosure is not limited thereto. 
     Specifically, as shown in  FIG. 1 , two opposite ends of the first conductive track  11  are respectively connected to a first positive bonding pad P 1  and a first negative bonding pad N 1 , and two opposite ends of the second conductive track  12  are respectively connected to a second positive bonding pad P 2  and a second negative bonding pad N 2 . For example, the first positive bonding pad P 1  and the second positive bonding pad P 2  can be arranged proximal to each other at a corner of the substrate  1 , and the first negative bonding pad N 1  and the second negative bonding pad N 2  are arranged proximal to each other at the opposite corner on the substrate  1 . The width of the first conductive track  11  extending from the first positive bonding pad P 1  to the first negative bonding pad N 1 , and the width of the second conductive track  12  extending from the second positive bonding bad P 2  to the second negative bonding pad N 2  gradually increase and decrease along a diagonal line on the substrate  1 , thereby increasing the area of distribution of the first conductive track  11  and the second conductive track  12 . 
     Moreover, referring to  FIG. 1  and  FIG. 2 , the light-emitting unit  2  includes a plurality of first light-emitting groups G 1  and a plurality of second light-emitting groups G 2 . The color temperature of the first light-emitting groups G 1  is smaller than the color temperature of the second light-emitting groups G 2 . Each of the first light-emitting groups G 1  includes one or more first LED chips  210 . Each of the second light-emitting groups G 2  includes one or more second LED chips  220 . Specifically, as shown in  FIG. 1 , each of the positive bonding pads  210 P of the first LED chips  210  and each of the positive bonding pads  220 P of the second LED chips  220  are all directed toward a first predetermined direction W 1  relative to the substrate  1 . Each of the negative bonding pads  210 N of the first LED chips  210  and each of the negative bonding pads  220 N of the second LEC chips  220  are all directed toward a second predetermined direction W 2  relative to the substrate  1 . The first predetermined direction W 1  and the second predetermined direction W 2  are opposite directions. By this configuration, regarding each individual chip, the orientation relative to the substrate  1  of the positive and negative bonding pads ( 210 P,  210 N) of each of the first LED chips  210  is the same as the orientation relative to the substrate  1  of the positive and negative bonding pads ( 220 P,  220 N) of each of the second LED chips  220 . During the process of disposing chips, the positive terminals and the negative terminals of the first LED chips  210  and the second LED chips  220  do not need to be turned, increasing production efficiency. 
     Specifically, in order to achieve the design of the above-mentioned “the orientation relative to the substrate  1  of the positive and negative bonding pads ( 210 P,  210 N) of each of the first LED chips  210  is the same as the orientation relative to the substrate  1  of the positive and negative bonding pads ( 220 P,  220 N) of each of the second LED chips  220 ,” the one or more first LED chips  210  of each of the first light-emitting groups G 1  can only be placed on one of the first chip-mounting lines  1100  of the respective first chip-mounting area  110 , and the one or more second LED chips  220  of each of the second light-emitting groups G 2  can only be placed on one of the second chip-mounting lines  1200  of the respective second chip-mounting area  120 . For example, as shown in  FIG. 1 , in order to orient the positive bonding pad  210 P of each of the first LED chips  210  toward the first predetermined direction W 1 , the one or more first LED chips  210  of each of the first light-emitting groups G 1  can only be placed on the first chip-mounting line  1100  closer to the first positive bonding pad P 1  of two neighboring first chip-mounting lines  1100 . Likewise, in order to orient the positive bonding pad  220 P of each of the second LED chips  220  toward the first predetermined direction W 1 , the one or more second LED chips  220  of each of the second light-emitting groups G 2  can only be placed on the second chip-mounting line  120  further from the second positive bonding pad P 2  of two neighboring second chip-mounting lines  1200 . 
     As shown in  FIG. 1 , in order to achieve the design of “the positive terminals and the negative terminals of the first LED chips  210  and the second LED chips  220  do not need to be turned,” the one or more first LED chips  210  of each of the first light-emitting groups G 1  can be disposed on the same corresponding first chip-mounting line  1100  of the first chip-mounting area  110 , to form first LED chips  210  which do not need to be turned to realign the positive terminal and the negative terminal during chip disposing process, and the one or more second LED chips  220  of each of the second light-emitting groups G 2  can be disposed on the same corresponding second chip-mounting line  1200  of the second chip-mounting area  120 , to form second LED chips  220  which do not need to be turned to realign the positive terminal and the negative terminal during chip disposing process. Additionally, since the first chip-mounting areas  110  and the second chip-mounting areas  120  are alternately arranged, the first light-emitting groups G 1  and the second light-emitting groups G 2  are also alternately arranged and capable increasing light mixing effect of light-emitting groups of different color temperatures. 
     For example, as shown in  FIG. 1 , the first LED chips  210  and the second LED chips  220  can be alternately arranged as an array, so that the first LED chips  210  and the second LED chips  220  present an alternating arrangement from a vertical or a horizontal perspective. Additionally, the first chip-mounting lines  1100  having first LED chips  210  disposed thereon and the second chip-mounting lines  1200  having second LED chips  220  disposed thereon can be parallel to each other and have the same interval distance D therebetween, such that any neighboring first light-emitting group G 1  and second light-emitting group G 2  can be parallel to each other and be separate by an interval distance D. Therefore, the light source of different color temperatures produced by the plurality of first light-emitting groups G 1  and the plurality of second light-emitting groups G 2  of the light-emitting unit  2  can be preferably mixed. For example, the first light-emitting groups G 1  can be LED units providing a first color temperature, and the second light-emitting groups G 2  can be LED units providing a second color temperature. The two sets of LED units producing two different color temperatures can be LED chips of wavelengths in similar ranges configured with two sets of different fluorescent gels, wherein the first color temperature is a relatively low color temperature corresponding to warm white, red, yellow or similar colors, and the second color temperature is a relatively high color temperature corresponding to cold white, blue, green or similar colors. 
     Specifically, as shown in  FIG. 1 , since the first conductive track  11  and the second conductive track  12  extend along a diagonal line of the substrate  1  such that the horizontal width of the meandering tracks present changes of “gradual increase and decrease,” so that the quantities of the first LED chips  210  of the first light-emitting groups G 1  and the quantities of the second LED chips  220  of the second light-emitting groups G 2  sequentially decrease from the middle of the light-emitting unit  2  toward two opposite sides of the light-emitting unit  2 , or sequentially increase from two opposite sides of the light-emitting unit  2  toward the middle of the light-emitting unit  2 . 
     For example, as shown in  FIG. 1 , the quantities of the first LED chips  210  and the quantities of the second LED chips  220  sequentially increase from two opposite corners toward the middle according to the respective formulas 2n−1 and 2n, wherein n is the sequence number of the first light-emitting groups G 1  and the second light-emitting groups G 2  starting from 1. Therefore, the quantities of the first LED chips  210  increase from the two corners to the middle of the light-emitting unit  2  according to the sequence (2×1−1=1, 2×2−1=3, 2×3−1=5), and the quantities of the second LED chips  220  increase from the two corners to the middle of the light-emitting unit  2  according to the sequence (2×1=2, 2×2=4). By this configuration, the quantities of first LED chips  210  of two neighboring first light-emitting groups G 1  differs by two, the quantities of second LED chips  220  of two neighboring second light-emitting groups G 2  differs by two, and the quantities of LED chips ( 210 ,  220 ) of a first light-emitting group G 1  and a neighboring second light-emitting group G 2  differ by 1. 
     Additionally, as show in  FIG. 1  to  FIG. 3 , the upper surface of the substrate  1  has an accommodating groove  13  for accommodating an electronic component  3 . The inner surface of the accommodating groove  13  has a light-absorbing coating  14 , and the interior of the substrate  1  has a thermal resistant structure disposed between the electronic component  3  and the light-emitting unit  2 . For example, the substrate  1  is a multi-layered ceramic plate which can be formed by Al 2 O 3 , an adhesive sheet, FR4, a metal layer and a shielding layer, or by AlN, a metal layer and a silicone layer. Light-emitting chips and a gel frame surrounding the light-emitting chips can be disposed on the above, and fluorescent gel can cover the light-emitting chips to form the light-emitting unit  2 . Moreover, the electronic component  3  can be an optical sensor, and the light-absorbing coating  14  can be a black coating for reducing reflection, increasing the sensing effect of the optical sensor. Additionally, the thermal resistant structure can be an air layer  15  (as shown in  FIG. 2 ) or a high thermal resistance material  15 ′ whose thermal resistance is higher than that of the substrate  1  (as shown in  FIG. 3 ), limiting the heat produced by the light-emitting unit  2  from being transmitted to the electronic component  3 . 
     Additionally, regarding the positioning of the electronic component  3  and the thermal resistant structure, for example as shown in  FIG. 1 , when the electronic component  3  is disposed proximal to a corner of the substrate  1 , the thermal resistant structure ( 15 ,  15 ′) can be slantedly disposed between the light-emitting unit  2  and the electronic component  3 . According to another possible positioning, when the electronic component  3  is disposed proximal to a transverse (horizontal) edge of the substrate  1 , the thermal resistant structure can be vertically (or levelly) disposed between the light-emitting unit  2  and the electronic component  3 . Specifically, the thermal resistant structure on the substrate  1  and the subsequent thermal conducting unit can be formed at the same time. In other words, a plurality of indentations or through holes is formed on the back of the substrate  1  at predetermined positions corresponding to the positions of the thermal resistant structure and the thermal conducting unit. The depths of indentations are the same. Then, the indentations or through holes of the thermal resistant structure can be unfilled (and air) or filled with material having high thermal resistance. The indentations or through holes of the thermal conducting unit can be filled with similar or different materials having high thermal conductivity. In other words, the thermal conductivities k 1 , k 2  and k 3  of respectively the substrate, the thermal resistant structure and the thermal conducting unit satisfy the relationship of k 3 &gt;k 1 &gt;k 2 . The present embodiment takes the strength of the substrate into consideration and employs a design of indentations. 
     Specifically, as shown in  FIG. 2  and  FIG. 3 , the substrate  1  further includes a thermal conducting unit  1 A embedded in the substrate  1 , and the thermal conducting unit  1 A includes a plurality of first heat dissipating structures  11 A disposed under the plurality of first LED chips  210  and a plurality of second heat dissipating structures  12 A disposed under the plurality of second LED chips  220 . For example, the first LED chips  210  and the second LED chips  220  become a first LED unit  21  and a second LED unit  22  after packaging (for example using similar or different fluorescent gel for packaging). When the color temperature produced by the first LED unit  21  is lower than the color temperature produced by the second LED unit  22 , the first heat dissipating structures  11   a  and the second heat dissipating structures  12 A can use the following design, for balancing the heat dissipation of the first LED unit  21  and the second LED unit  22 . Firstly, in the first type, when the first heat dissipating structures  11 A and the second heat dissipating structures  12 A use materials having similar heat dissipating ability, the overall dimensions (or volume) of the first heat dissipating structures  11 A is greater than the overall dimensions (or volume) of the second heat dissipating structures  12 A. Additionally, in the second type, when the dimensions of the first heat dissipating structures  11   a  and the second heat dissipating structures  12 A are similar, the heat dissipating ability of the material used by the first heat dissipating structures  11 A is greater than the heat dissipating ability of the material used by the second heat dissipating structures  12 A. However, the present disclosure is not limited thereto. Additionally, the first LED unit  21  and the second LED unit  22  of different color temperatures results in different contact face temperatures. Therefore, the heat transfer rate Q 1  of the first heat dissipating structures  11 A and the heat transfer rate Q 2  of the second heat dissipating structures  12 A can have a ratio Q 1 :Q 2 =1:0.86-0.95. Under this preferable ratio, the present embodiment can reduce the difference between the contact face temperatures of the first LED unit  21  and the second Led unit  22 . If the light emitted by the first LED unit  21  is warm color temperature 2700K, and the light emitted by the second LED unit  22  is cold color temperature 5700K, for example, then the preferred ratio of heat transfer rate Q 1  of the first heat dissipating structures  11 A to the heat transfer rate Q 2  of the second heat dissipating structures  12 A is 1:0.92. 
     Referring to  FIG. 4 , taking the 6×6 array of LED chips ( 210 ,  220 ) for example, the total quantity of second Led chips  210  is equal to the total quantity of the second LED chips  220 . When the LED chips proximal to the four corners of the substrate  1  are removed (as shown by dotted lines labeled as  210 ,  220  in  FIG. 4 ), the first LED chips  210  and the second LED chips  220  present an arrangement distribution which is “approximately circular.” Specifically, 4 of the first LED chips  210  are positioned at the outer periphery (labeled as  210 ′), and 4 of the second LED chips  220  are positioned at the outer periphery (labeled as  220 ′). Whether using the 4 first LED chips  210 ′ at the outer periphery or the 4 second LED chips  220 ′ at the outer periphery as basis (shown as black dots in  FIG. 4 ), a circular path T can be drawn as shown in  FIG. 4 . In a preferred design, the circular track T drawn by using the 4 first LED chips  210 ′ at the outer periphery as basis and the circular track T drawn by using the 4 second LED chips  220 ′ at the outer periphery as basis substantially overlap or completely overlap to form a single circular track T. 
     Referring to  FIG. 5 , in order for the first LED chips (labelled as  210 ″) proximal to the circular track T to fall exactly on the circular track T, the present disclosure provides a method: when laying the first chip-mounting lines  1100 , deviating lines  11000  on the first chip-mounting lines  1100  are designed to directly pass the circular track T. Therefore, when the first LED chips  210 ″ are offset from the original positions in the direction indicated by arrows shown in  FIG. 5  onto the intersections between the deviating lines  11000  and the circular track T, the first LED chips  210 ″ fall directly on the circular track T. Moreover, in order for the second LED chips (labelled as  220 ″) proximal to the circular track T to fall exactly on the circular track T, the second chip-mounting line  1200  does not need to be modified, the outer second LED chips  220 ″ only need to be offset along the second chip-mounting line  1200  in the direction indicated by arrows shown in  FIG. 5 , and the second LED chips  220 ″ will fall directly on the circular track T. By this configuration, the first LED chips  210 ″ and the second LED chips  220 ″ proximal to the circular track T can be offset to fall directly on the circular track T, so the first LED chips  210  and the second LED chips  220  can present an arrangement distribution which is “approximately circular.” 
     Referring to  FIG. 6 , in order for the first LED chips (labelled as  210 ″) proximal to the circular track T to fall exactly on the circular track T, the present disclosure provides another method: when laying the first chip-mounting lines  1100 , width-extension segments  11000 ′ reaching the circular track T are designed on the first chip-mounting line  110 , so that the first LED chips  210 ″ proximal to the circular track T can be directly offset on the width-extension segments  11000 ′ without modifying the original path of the first chip-mounting lines  1100 . Therefore, when the first LED chips  210 ″ are offset from the original positions in the direction indicated by arrows shown in  FIG. 6  onto the circular track T, the first LED chips  210 ″ fall directly on the circular track T. 
     As shown in  FIG. 7 , the first chip-mounting lines  1100  and the second chip-mounting lines  1200  can be modified from the “slanted design” of  FIG. 4  to a “vertical design.” This vertical design also allows the first LED chips  210  and the second LED chips  220  to present an arrangement distribution which is “approximately circular.” Of course, through the design of offsetting LED chips as disclosed in  FIG. 5  or  FIG. 6 , the first LED chips  210  and the second LED chips  220  can likewise be made to present an arrangement distribution which is “circular.” 
     In other words, when presenting a “circular” arrangement distribution, the total quantity of the first LED chips  210  and the total quantity of the second LED chips  220  are equal. The quantities of LED chips ( 210 ,  220 ) of a first light-emitting group G 1  and a neighboring second light-emitting group G 2  differ by 1. Therefore when the quantity of the first LED chips  210  of each of the first light-emitting groups G 1  is N, the quantity of the second LED chips  220  of each of the second light-emitting groups G 2  is N+1, the quantity of the first light-emitting groups G 1  is N+1, and the quantity of the second light-emitting groups G 2  is N, so the total quantity of each type of LED chip is N*(N+1). 
     Additionally, the color temperature produced by the first LED unit  21  is lower than the color temperature produced by the second LED unit  22 , and the heat produced by the first LED unit  21  is greater than the heat produced by the second LED unit  22 . So in consideration of overall ability to dissipate heat, the first light-emitting groups G 1  of warm color temperature can be distributed at the periphery of the substrate (two sides being first light-emitting groups G 1 ) to prevent heat from gathering and leading to decline in light-emitting efficiency. Therefore, as shown in  FIG. 7 , the color temperatures of the light-emitting groups from the left to right are respectively cold, warm, cold, warm, cold, warm, cold, warm, cold, and the quantities of LED chips are respectively 3, 4, 3, 4, 3, 4 and 3. 
     Referring to  FIG. 8 , under the condition that the present disclosure uses a common substrate  1 , two or more independent light-emitting structures can be arranged, and each of the light-emitting structures has an independent first and second positive bonding pads (P 1 , P 2 ) and first and second negative bonding pads (N 1 , N 2 ). Through the arrangement of two or more independent light-emitting structures, the first LED chips  210  and the second Led chips  220  not only can present an “array” arrangement distribution as shown in  FIG. 7 , but also through a design shown in  FIG. 4  present an “approximately circular” arrangement distribution. Of course, a design of  FIG. 5  of  FIG. 6  can be used to present a “circular” arrangement distribution. 
     It is worth noting that after the independent light-emitting structures disclosed in  FIG. 9  are connected in parallel, the light-emitting structures can commonly use the same first and second positive bonding pads (P 1 , P 2 ) and the same first and second negative bonding pads (N 1 , N 2 ). For example, as shown in  FIG. 9 , assume that the left side and the right side of  FIG. 9  are respectively the first and second light-emitting structures, and the first chip-mounting lines  1100  of the first and second light-emitting structures can share the same first positive bonding pad P 1  and the same negative bonding pad N 1 . The first chip-mounting lines  1100  of the first light-emitting structure are directly connected on the upper surface of the substrate  1  to the first positive bonding pad P 1 . The first chip-mounting lines  1100  of the second light-emitting structure are connected to the first positive bonding pad P 1  by passing through a first via hole V 1  and in configuration with a first backside circuit C 1  on the backside of the substrate  1 . The first chip-mounting lines  1100  of the first and second light-emitting structures are directly connected on the upper surface of the substrate  1  to the first negative bonding pad N 1 . Additionally, the second chip-mounting lines  1200  of the first and second light-emitting structures are directly connected on the upper surface of the substrate  1  to the second positive bonding pad P 2 . The second chip-mounting lines  1200  of the first light-emitting structure are connected to the second negative bonding pad N 2  by passing through a second via hole V 2  and in configuration with a second backside circuit C 2  on the backside of the substrate  1 . The second chip-mounting lines  1200  of the second light-emitting structure are directly connected on the upper surface of the substrate  1  to the second negative bonding pad N 2 . In other words, one end of the first conductive track  11  and one end of the second conductive track  12  of the first light-emitting structure are respectively connected to the first positive bonding pad P 1  and the second positive bonding pad P 2 , and one end of the first conductive track  11  and one end of the second conductive track  12  of the second light-emitting structure are respectively connected to the first negative bonding pad N 1  and the second negative bonding pad N 2 . The other end of the first conductive track  11  of the second light-emitting structure sequentially through the first via hole and the first backside circuit C 1  is indirectly connected to the first positive bonding pad P 1 , and the other end of the second conductive track  12  of the second light-emitting structure is directly connected to the second positive bonding pad P 2 . The other end of the first conductive track  11  of the first light-emitting structure is connected to the first negative bonding pad N 1 , and the other end of the second conductive track  12  of the first light-emitting structure sequentially through the second via hole and the second backside circuit C 2  is indirectly connected to the second negative bonding pad N 2 . 
     Additionally, regardless of whether the first chip-mounting lines  1100  and the second chip-mounting lines  1200  are “slanted designs” or “vertical designs,” the first chip-mounting lines  1100  and the second chip-mounting lines  1200  are preferably parallel. The positive first LED chips  210  and the second LED chips  220  do not need to turn the positive and negative terminals during chip disposing on the same row. In other words, the positive bonding pad  210 P of each of the first LED chips  210  and the positive bonding pad  220 P of each of the second LED chips  220  face toward the same first predetermined direction Wr, and the negative bonding pad  210 N of each of the first LED chips  210  and the negative bonding pad  220 N of each of the second LED chips  220  face toward the same second predetermined direction W 2 ′. 
     Second Embodiment 
     Referring to  FIG. 10 , the second embodiment of the present disclosure provides a light-emitting structure. From comparison of  FIG. 10  to  FIG. 2  (or  FIG. 3 ), it can be seen that the greatest difference between the first and second embodiments of the present disclosure lies in that: in the second embodiment, the sizes of the first heat dissipating structures  11 A and the second heat dissipating structures  12 A gradually decreases from the center of the substrate  1  toward the periphery of the same. By this configuration, the difference between the contact face temperatures of the “first and second LED units ( 21 ,  22 ) at the central region of the substrate  1 ” and the “first and second LED units ( 21 ,  22 ) at the peripheral region (the region surrounding the central region) of the substrate  1 .” Specifically, looking from the center of the substrate  1  toward the periphery, the dimensions of the first heat dissipating structures  11 A sequentially decrease by 10% from the center to the periphery (namely the dimensions of two neighboring first heat dissipating structures  11 A differ by 10%), and the dimensions of the second heat dissipating structures  12 A sequentially decrease by 10% from the center to the periphery (namely the dimensions of two neighboring second heat dissipating structures  12 A differ by 10%). Additionally, the heat dissipating ability of a second heat dissipating structure  12 A is roughly 0.86-0.95 times that of a neighboring first heat dissipating structure  11 A. 
     Third Embodiment 
     Referring to  FIG. 11 , the third embodiment of the present disclosure provides a light-emitting structure. From comparison of  FIG. 11  to  FIG. 2  (or  FIG. 3 ), it can be seen that the greatest difference between the third and first embodiment of the present disclosure lies in that: in the third embodiment, the bottom of the substrate  1  further includes a thermal spreading unit  1 B contacting the thermal conducting unit  1 A, wherein the interior of the thermal spreading unit  1 B includes a plurality of heat dissipating channels  10 B which have similar dimensions and are separate, and the gap distances (A, B, C) between two neighboring heat dissipating channels  10 B increase from the center of the thermal spreading unit  1 B toward the periphery of the same. By this configuration, the heat dissipating channels  10 B are sequentially arranged in the direction of “from the center to the periphery of the thermal spreading unit  1 B” or “from the periphery to the center of the thermal spreading unit  1 B,” to form an incremental thermal conduction structure. Typically, temperature closer to the center is higher. Marking boundaries at every difference of five degrees Kelvin, three heat dissipating regions are defined as shown in  FIG. 11  presenting a side cross-sectional view of the light-emitting structure. The three heat dissipating regions (X, Y, Z) progressively cover less horizontal distance from the heat dissipating region X to the heat dissipating region Z. For example, the ratio of the distances of the three heat dissipating regions can be X:Y:Z=5:4:3. When the dimensions of the heat dissipating channels  10 B are similar, the gap distances (A, B, C) between two neighboring heat dissipating channels  10 B increases from the center to the periphery of the thermal spreading unit  1 B (e.g. A:B:C=3:4:5). Therefore the temperature difference between the “first and second LED units ( 21 ,  22 ) at the central region of the thermal spreading unit  1 B” and the “first and second LED units ( 21 ,  22 ) at the peripheral region (the region surrounding the central region) of the thermal spreading unit  1 B” can be reduced. 
     Additionally, each of the heat dissipating channels  10 B can be a solid heat conducting column formed by a through hole  100  and a heat conducting material  101 B (e.g. metal material having high thermal conductivity) completely filling the through hole  100 B. The heat dissipating channels  10 B can completely pass through the thermal spreading unit  1 B. However the present disclosure is not limited thereto. For example, the heat conducting material  101 B does not need to completely fill the corresponding through holes  100 B, and the heat dissipating channels  10 B do not need to completely pass through the thermal spreading unit  1 B. 
     Fourth Embodiment 
     Referring to  FIG. 12 , the fourth embodiment of the present disclosure provides a light-emitting structure. From comparing  FIG. 12  to  FIG. 11 , it can be seen that the greatest difference between the fourth and third embodiment of the present disclosure lies in that: in the fourth embodiment, the, the volumetric density (D 1 , D 2 , D 3 ) of the heat dissipating channels  10 B occupying the thermal spreading unit  1 B decreases from the center to the periphery of the thermal spreading unit  1 B. 
     For example, marking boundaries at every difference of five degrees Kelvin, three heat dissipating regions are defined as shown in  FIG. 12  presenting a side cross-sectional view of the light-emitting structure. The three heat dissipating regions (X, Y, Z) progressively cover less horizontal distance from the heat dissipating region X to the heat dissipating region Z. For example, the ratio of the distances of the three heat dissipating regions can be X:Y:Z=5:4:3. When the dimensions of the heat dissipating channels  10 B are similar, the volumetric densities (D 1 , D 2 , D 3 ) of heat dissipating channels  10 B occupying the thermal spreading unit  1 B decreases from the heat dissipating region X to the heat dissipating region Z (e.g. D 1 :D 2 :D 3 =6.5:2:1). Therefore the temperature difference between the “first and second LED units ( 21 ,  22 ) at the central region of the thermal spreading unit  1 B” and the “first and second LED units ( 21 ,  22 ) at the peripheral region of the thermal spreading unit  1 B” can be reduced. 
     Fifth Embodiment 
     Referring to  FIG. 13 , the fifth embodiment of the present disclosure provides a light-emitting structure. From comparison of  FIG. 13  to  FIG. 11 , it can be seen that the greatest difference between the fifth and third embodiment of the present disclosure lies in that: in the fifth embodiment, the interior of the thermal spreading unit  1 B includes a plurality of separate heat dissipating channels  10 B, and the dimensions (S 1 , S 2 , S 3 ) of the thermal dissipating channels  10 B decrease from the center to the periphery of the thermal spreading unit  1 B. 
     For example, marking boundaries at every difference of five degrees Kelvin, three heat dissipating regions are defined as shown in  FIG. 13  presenting a side cross-sectional view of the light-emitting structure. The three heat dissipating regions (X, Y, Z) progressively cover less horizontal distance from the heat dissipating region X to the heat dissipating region Z. For example, the ratio of the distances of the three heat dissipating regions can be X:Y:Z=5:4:3. The fifth embodiment uses heat dissipating channels  10 B of different dimensions, and the dimensions (S 1 , S 2 , S 3 ) of the heat dissipating channels  10 B decrease from the heat dissipating region X to the heat dissipating region Y (e.g. S 1 :S 2 :S 3 =5:4:3). Therefore, the heat dissipating effect of the “first and second LED units ( 21 ,  22 ) at the central region of the thermal spreading unit  1 B” is better than the heat dissipating effect of the “first and second LED units ( 21 ,  22 ) at the peripheral region of the thermal spreading unit  1 B,” thereby reducing the temperature difference between the “first and second LED units ( 21 ,  22 ) at the central region of the thermal spreading unit  1 B” and the “first and second LED units ( 21 ,  22 ) at the peripheral region of the thermal spreading unit  1 B.” 
     Sixth Embodiment 
     Referring to  FIG. 14 , the sixth embodiment of the present disclosure provides a light-emitting structure. From comparison of  FIG. 14  to  FIG. 11 , it can be seen that the greatest difference between the sixth and third embodiment of the present disclosure lies in that: in the sixth embodiment, the thermal conducting unit  1 A of the third embodiment and the thermal spreading unit  1 B are integrated to form a compound thermal dissipating layer  1 AB. Specifically, each of the first heat dissipating structures  11 A positioned in the compound heat dissipating layer  1 AB is closely surrounded by heat dissipating channels  10 B which are separate and have similar dimensions, and the gap distances (A, B, C) between two neighboring heat dissipating channels  10 B increase in the direction from the center to the periphery of the corresponding first heat dissipating structure  11 A. Likewise, each of the second heat dissipating structures  12 A positioned in the compound heat dissipating layer  1 AB is closely surrounded by heat dissipating channels  10 B which are separate and have similar dimensions, and the gap distances (A, B, C) between two neighboring heat dissipating channels  10 B increase in the direction from the center to the periphery of the corresponding second heat dissipating structure  12 A. By this method, the present embodiment can reduce the temperature difference between the first and second LED units ( 21 ,  22 ) of different color temperatures. 
     Seventh Embodiment 
     Referring to  FIG. 15 , the seventh embodiment of the present disclosure provides a light-emitting structure. From comparison of  FIG. 15  to  FIG. 12 , it can be seen that the greatest difference between the seventh and fourth embodiment of the present disclosure lies in that: in the seventh embodiment, the thermal conducting unit  1 A of the fourth embodiment and the thermal spreading unit  1 B are integrated to form a compound thermal dissipating layer  1 AB. Specifically, each of the first heat dissipating structures  11 A positioned in the compound heat dissipating layer  1 AB is closely surrounded by heat dissipating channels  10 B which are separate and have similar dimensions, and the volumetric densities (D 1 , D 2 , D 3 ) of the heat dissipating channels  10 B decrease in the direction from the center to the periphery of the corresponding first heat dissipating structure  11 A. Likewise, each of the second heat dissipating structures  12 A positioned in the compound heat dissipating layer  1 AB is closely surrounded by heat dissipating channels  10 B which are separate and have similar dimensions, and the volumetric densities (D 1 , D 2 , D 3 ) of the heat dissipating channels  10 B decrease in the direction from the center to the periphery of the corresponding second heat dissipating structure  12 A. By this method, the present embodiment can reduce the temperature difference between the first and second LED units ( 21 ,  22 ) of different color temperatures. 
     Eighth Embodiment 
     Referring to  FIG. 16 , the eighth embodiment of the present disclosure provides a light-emitting structure. From comparison of  FIG. 16  to  FIG. 13 , it can be seen that the greatest difference between the eighth and fifth embodiment of the present disclosure lies in that: in the seventh embodiment, the thermal conducting unit  1 A of the fourth embodiment and the thermal spreading unit  1 B are integrated to form a compound thermal dissipating layer  1 AB. Specifically, each of the first heat dissipating structures  11 A positioned in the compound heat dissipating layer  1 AB is closely surrounded by heat dissipating channels  10 B which are separate, and the dimensions (S 1 , S 2 , S 3 ) of the heat dissipating channels  10 B decrease in the direction from the center to the periphery of the corresponding first heat dissipating structure  11 A. Likewise, each of the second heat dissipating structures  12 A positioned in the compound heat dissipating layer  1 AB is closely surrounded by heat dissipating channels  10 B which are separate, and the dimensions (S 1 , S 2 , S 3 ) of the heat dissipating channels  10 B decrease in the direction from the center to the periphery of the corresponding second heat dissipating structure  12 A. By this method, the present embodiment can reduce the temperature difference between the first and second LED units ( 21 ,  22 ) of different color temperatures. 
     Ninth Embodiment 
     Referring to  FIG. 17  and  FIG. 18 , the ninth embodiment of the present disclosure provides a light-emitting structure. During production, firstly a frame gel body  4  is formed on the substrate  1  (such as a circuit board) having a predetermined circuit (as shown in  FIG. 17 ). Then, first fluorescent gels  51  and second fluorescent gels  52  which are different respectively fill corresponding first restricting spaces  401  and corresponding second restricting spaces  402  (as shown in  FIG. 18 ). 
     Specifically, as shown in  FIG. 17 , the frame gel body  4  includes an outer frame portion  40  arranged on the substrate  1  and surrounding the light-emitting unit  2 , and a plurality of connecting portions  41  arranged on the substrate  1  and surrounded by the outer frame portion  40 . Two opposite ends of each of the connecting portions  41  are connected to an inner face of the outer frame portion  40 . Each of the connecting portions  41  is arranged between a first light-emitting group G 1  and a neighboring second light-emitting group G 2 , to form a plurality of first restricting spaces  401  for accommodating the first light-emitting groups G 1  and a plurality of second restricting spaces  402  for accommodating the second light-emitting groups G 2 . The first restricting spaces  401  and the second restricting spaces  402  are alternately arranged. Moreover, as shown in  FIG. 18 , a package gel body  5  includes a plurality of first fluorescent gels  51  filled in the plurality of first restricting spaces  401  for covering the first light-emitting groups G 1 , and a plurality of second fluorescent gels  52  filled in the plurality of second restricting spaces  402  for covering the second light-emitting groups G 2 , such that the first fluorescent gels  51  and the second fluorescent gels  52  are alternately arranged. 
     In practice, the light produced by the first LED chips  210  (bare chips which have not been packaged) of the first light-emitting groups G 1  can pass through the first fluorescent gels  51  to produce a warm white light, and the light produced by the second LED chips  220  (bare chips which have not been packaged; the two bare chips of the present embodiment have be of same wavelength range) of the second light-emitting groups G 2  can pass through the second fluorescent gels  52  to produce a cold white light. The ninth embodiment of the present disclosure achieves preferred light mixing effect through the design of “alternate arrangement of first light-emitting groups G 1  formed by corresponding first fluorescent gels  51  and second light-emitting groups G 2  formed by corresponding second fluorescent gels  52 .” 
     Tenth Embodiment 
     Referring to  FIG. 19  and  FIG. 20 , the tenth embodiment of the present disclosure provides a light-emitting structure. During production, firstly a frame gel body  4  is formed on the substrate  1  (as shown in  FIG. 19 ). Then first fluorescent gels  51  having high thixotropic coefficient respectively cover the first light-emitting groups G 1  to form a plurality of restricting spaces  400  for accommodating second light-emitting groups G 2  (as shown in  FIG. 19 ). Finally, second fluorescent gels  52  having a typical thixotropic coefficient are filled in the restricting spaces  400  to respectively cover the second light-emitting groups G 2  (as shown in  FIG. 20 ). 
     Specifically, as shown in  FIG. 19  and  FIG. 20 , the frame gel body  4  includes an outer frame portion arranged on the substrate  1  and surrounding the light-emitting unit  2  and the package gel body  5 . The package gel body  5  includes a plurality of first fluorescent gels  51  covering the plurality of first restricting spaces  401  for covering the first light-emitting groups G 1 , and a plurality of second fluorescent gels  52  covering the plurality of second restricting spaces  402  for covering the second light-emitting groups G 2 , such that the first fluorescent gels  51  and the second fluorescent gels  52  are alternately arranged. In practice, the light produced by the first LED chips  210  of the first light-emitting groups G 1  can pass through the first fluorescent gels  51  to produce a relatively low first color temperature, and the light produced by the second LED chips  220  of the second light-emitting groups G 2  can pass through the second fluorescent gels  52  to produce a relative high second color temperature. 
     In summary of the above, the advantage of the present disclosure lies in that the light-emitting structure provided by the embodiments of the present disclosure can increase the light mixing effect between the plurality of first light-emitting groups G 1  and the plurality of second light-emitting groups G 2  of different color temperatures through the designs of “the one or the plurality of first LED chips  210  of a first light-emitting group G 1  is disposed on the same first chip-mounting line  1100  of the corresponding first chip-mounting area  110 , and the one or the plurality of second LED chips  220  of a second light-emitting group G 1  is disposed on the same second chip-mounting line  1200  of the corresponding first chip-mounting area  120 ” and “the first chip-mounting areas  110  and the second chip-mounting areas  120  are alternately arranged, such that the first light-emitting groups G 1  and the second light-emitting groups G 2  are alternately arranged.” 
     It is worth mentioning that color tunable LEDs device by a combination of warm white (2700K) and cool white (5000K) multi CSP (Chip Scale Package) LEDs. It shows ultra-uniform mixing color by homogeneous alignment, and also smooth tuning by varying their relative driving current. It is revolutionary, energy efficient and compact new variable color light source, combining the long lifetime and reliability advantages. It provides a total design freedom and creating a new opportunities for application of intelligent lighting. 
     The descriptions illustrated supra set forth simply the preferred embodiments of the present disclosure; however, the characteristics of the present disclosure are by no means restricted thereto. All changes, alternations, or modifications conveniently considered by those skilled in the art are deemed to be encompassed within the scope of the present disclosure delineated by the following claims.