BACKGROUND 
     1. Technical Field 
     The present disclosure relates to a light-emitting device, and more particularly, to a light-emitting device having multiple optical elements and a manufacturing method thereof. 
     2. Description of the Related Art 
     An optoelectronic device, such as a light-emitting diode (LED) package, has been applied widely to optical display devices, traffic signals, data storing devices, communication devices, illumination devices, and medical apparatuses. The LED can be connected with other elements to form a light-emitting device.  FIG. 1  illustrates a schematic view of a conventional light-emitting device. A conventional light-emitting device  1  includes a submount  12  with a circuit  14 ; a solder  16  on the submount  12 , wherein an LED  11  is adhesively fixed on the submount  12  by the solder  16 ; and an electrical-connecting structure  18  electrically connecting the n-type electrode  15  with the circuit  14 . The submount  12  can be a lead frame or a mounting substrate for circuit design and heat dissipation of the light-emitting apparatus  1 . However, because of the trend of small and slim commercial electronic product, the development of the optoelectronic device also enters an era of miniature package. One promising packaging design for semiconductor and optoelectronic device is the Chip-Level Package (CLP). 
     SUMMARY OF THE DISCLOSURE 
     A method of manufacturing a light-emitting device includes forming a first optical element on a first carrier, wherein the first optical element comprises an opening; forming a light-emitting element in the opening; forming a second optical element on the light-emitting element; forming a second carrier on the first optical element and the second optical element; removing the first carrier after forming the second carrier on the first optical element and the second optical element; and forming two separated conductive structures under the first optical element. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings are included to provide easy understanding of the application, are incorporated herein and constitute a part of this specification. The drawings illustrate embodiments of the application and, together with the description, serve to illustrate the principles of the application. 
         FIG. 1  illustrates a cross-sectional view of a conventional light-emitting device. 
         FIGS. 2A-2D  illustrate a flow chart of the manufacturing process of a light-emitting device in accordance with an embodiment of the present application. 
         FIG. 3  illustrates a cross-sectional view of a light-emitting device in accordance with another embodiment of the present application. 
         FIG. 4  illustrates a cross-sectional view of a light-emitting device in accordance with another embodiment of the present application. 
         FIG. 5  illustrates a cross-sectional view of a light-emitting device in accordance with another embodiment of the present application. 
         FIG. 6  illustrates a schematic diagram of a light-generating device in accordance with an embodiment of the present application. 
         FIG. 7  illustrates a schematic diagram of a back light module in accordance with an embodiment of the present application. 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     To better and concisely explain the disclosure, the same name or the same reference number given or appeared in different paragraphs or figures along the specification should has the same or equivalent meanings while it is once defined anywhere of the disclosure. 
     The following shows the description of the embodiments of the present disclosure in accordance with the drawings. 
       FIGS. 2A-2D  illustrate a flow chart of the manufacturing process of a light-emitting device  2  in accordance with an embodiment of the present disclosure. Referring to  FIG. 2A , a first optical element  22  is formed on a first carrier  20  and includes an opening  222  to expose the first carrier  20 . A light-emitting element  24  is formed on the exposed portion of the first carrier  20  and a wavelength-converting layer  26  is formed on the light-emitting element  24 , as shown in  FIG. 2B . In another embodiment, an electronic component (not shown) can be formed on the first carrier  20  as well. Referring to  FIG. 2C , a second optical element  28  is formed on the wavelength-converting layer  26 . A bonding layer  21  is formed under a second carrier  23 , and/or on the first optical element  22  and the second optical element  28 . The second carrier  23  is bonded to the second optical element  28  through a bonding process. The first carrier  20  is removed. A conductive structure  25  is formed under the first optical element  22  and the light-emitting element  24  to form the light-emitting device  2 , wherein the conductive structure  25  is electrically connected with the light-emitting element  24 . 
     The first carrier  20  and/or the second carrier  23  support the first optical element  22 , the second optical element  28 , and the light-emitting element  24 . The material of the first carrier  20  and/or the second carrier  23  includes conductive material such as Diamond Like Carbon (DLC), Metal Matrix Composite (MMC), Ceramic Matrix Composite (CMC), Polymer Matrix Composite (PMC), Cu, Al, Si, Mo, Cu—Sn, Cu—Zn, Cu—Cd, Ni—Sn, Ni—Co, Au alloy, SiC, GaP, GaAsP, InP, LiGaO 2 , or LiAlO 2 , or insulating material such as diamond, glass, polymer, epoxy, quartz, acryl, Al 2 O 3 , ZnO, or MN. 
     The first optical element  22  and/or the second optical element  28  can guide and/or extract light emitted from the light-emitting element  24  to the environment for improving the light extraction efficiency of the light-emitting device  2 . The material of the first optical element  22  and/or the second optical element  28  can be transparent material such as epoxy, polyimide (PI), benzocyclobutene (BCB), perfluorocyclobutane (PFCB), Su8, acrylic resin, polymethyl methacrylate (PMMA), polyethylene terephthalate (PET), polycarbonate (PC), polyetherimide, fluorocarbon polymer, glass, Al 2 O 3 , SINR, spin-on-glass (SOG), or the combination thereof. In another embodiment, the first optical element  22  can be reflector including metal such as Cu, Al, Sn, Au, Ag, Ti, Ni, Ag—Ti, Ni—Sn, Au alloy, Ni—Ag, Ti—Al, or the combination thereof. In another embodiment, a reflective layer can be formed on the surfaces of the first topical element  22  to reflect the light from the light-emitting element  24 . The material of the reflective layer can be the same as the aforementioned metal. The light from the light-emitting element  24  can be reflected by the first optical element  22  for improving the light extraction efficiency of the light-emitting device  2 . The shape of the second optical element  28  includes but is not limited to triangle, semicircle, quarter circle, trapezoid, pentagon, or rectangle in the cross-sectional view. An encapsulant can be formed between the second optical element  28  and the light-emitting element  24  in another embodiment to improve the light extraction efficiency of the light-emitting device  2 . 
     The light-emitting element  24  can be LED or Organic LED (OLED) and emit a first light with a first wavelength. The wavelength-converting layer  26  can receive the first light and generate a second light with a second wavelength, wherein the second wavelength is different from the first wavelength. The material of the wavelength-converting layer  26  can be phosphor such as yttrium aluminum garnet, silicate garnet, vanadate garnet, mixed oxides, alkaline earth metal silicates, alkaline earth metal sulfides, selenides, alkaline earth metal thlogallates, metal nitrides, metal oxo-nitrides and mixed molybdate-tungstate families, or mixed glass phosphors. The material of the wavelength-converting layer  26  can be semiconductor including more than one element selected from a group consisting of Ga, Al, In, As, P, N, Zn, Cd, and Se as well. The wavelength-converting layer  26  can be disposed on the light-emitting element  24  or be formed conformably around the contour thereof. 
     The bonding layer  21  can adhesively connect the first optical element  22  and/or the second optical element  28  with the second carrier  23 . The material of the bonding layer  21  can be transparent material such as polyimide, BCB, PFCB, MgO, Su8, epoxy, acrylic resin, COC, PMMA, PET, PC, polyetherimide, fluorocarbon polymer, glass, Al 2 O 3 , SiO, TiO 2 , SiN X , SOG, and so on. The bonding layer  21  can be UV tape or foam as well. 
     The conductive structure  25  is for receiving external voltage. The materials of the conductive structure  25  can be transparent conductive material and/or metal material. The transparent conductive material includes but is not limited to ITO, InO, SnO, CTO, ATO, AZO, ZTO, ZnO, IZO, DLC, GZO, and so on. The metal material includes but is not limited to Cu, Al, In, Sn, Au, Pt, Zn, Ag, Ti, Ni, Pb, Pd, Ge, Ni, Cr, Cd, Co, Mn, Sb, Bi, Ga, W, Be, Ag—Ti, Cu—Sn, Cu—Zn, Cu—Cd, Sn—Pb—Sb, Sn—Pb—Zn, Ni—Sn, Ni—Co, Ag—Cu, Ge—Au, Au alloy, and so on. The area of the bottom surface of the conductive structure  25  is larger than that of the light-emitting element  24 . It can be at least 2 times area of the bottom surface of the light-emitting element  24 . The conductive structure  25  can effectively release the heat from the light-emitting element  24  for improving the efficiency thereof. In addition, there is an insulating-diffusing layer (not shown) formed between the light-emitting element  24  and the conductive structure  25  in another embodiment. The insulating-diffusing layer can reflect and diffuse the light from the light-emitting element  24  to improve the light extraction efficiency of the light-emitting device  2 . The material of the insulating-diffusing layer includes but is not limited to epoxy, SiO, Al 2 O 3 , TiO 2 , silicone, resin, or the combination thereof. In another embodiment, a reflective layer can be formed between the light-emitting element  24  and the conductive structure  25  to reflect the light from the light-emitting element  24 . The material of the reflective layer can be the same as the aforementioned metal. The light from the light-emitting element  24  can be reflected by the reflective layer for improving the light extraction efficiency of the light-emitting device  2 . 
       FIG. 3  shows another embodiment that a light-emitting device  3  is similar to the light-emitting device  2 . In addition, the light-emitting device  3  includes a second optical element  30  which has a top surface at the same elevation as that of the first optical element  22  in a cross-sectional view. The top surface of the second optical element  30  is flat so it benefits the bonding process and reinforcing the structure of the light-emitting device  2 .  FIG. 4  shows another embodiment that a light-emitting device  4  is similar to the light-emitting device  2 . In addition, the light-emitting device  4  includes a second optical element  40  which has a top surface lower than that of the first optical element  22 . Therefore, other optical elements can be formed easily on the second optical element  40  to tune the optical field for the application. 
     Referring to  FIG. 5 , a light-emitting device  5  is similar to the light-emitting device  2 . In addition, the light-emitting device  5  includes an electronic component  50  such as rectifier, protection component, capacity, resistance, and so on. The electronic component  50  having various functions can control the current of the light-emitting element  24  based of the requirement of the application. It can be formed within the step of forming the light-emitting element  24  of the above manufacturing process. Preferably, the amount of the electronic component  50  and the light-emitting element  24  can be more than two, so the steps of the manufacturing process are reduced and the cost of the manufacturing is lowered. The electronic component  50  and the light-emitting element  24  can be electrically connected by the conductive structure  25 . The light-emitting device  5  further includes a wavelength-converting layer  52  on the second optical element  28 . 
       FIG. 6  illustrates a schematic diagram of a light-generating device  6 . The light-generating device  6  includes the light-emitting device of anyone of the foregoing embodiments of the present application. The light-generating device  6  can be an illumination device such as a street light, a lamp of vehicle, or an illustration source for interior. The light-generating device  6  can be also a traffic sign or a backlight of a backlight module of an LCD. The light-generating device  6  includes a light source  61  adopting any foregoing light-emitting devices; a power supplying system  62  providing current to the light source  61 ; and a control element  63  controlling the power supplying system  62 . 
       FIG. 7  illustrates a schematic diagram of a backlight module  7 . A backlight module  7  includes the light-generating device  6  of the foregoing embodiment and an optical element  71 . The optical element  71  can process the light generated by the light-generating device  6  for LCD application, such as scattering the light emitted from the light-generating device  6 . 
     It will be apparent to those having ordinary skill in the art that various modifications and variations can be made to the devices in accordance with the present disclosure without departing from the scope or spirit of the disclosure. In view of the foregoing, it is intended that the present disclosure covers modifications and variations of this disclosure provided they fall within the scope of the following claims and their equivalents.
A method of manufacturing a light-emitting device includes forming a first optical element on a first carrier, wherein the first optical element comprises an opening; forming a light-emitting element in the opening; forming a second optical element on the light-emitting element; forming a second carrier on the first optical element and the second optical element; removing the first carrier after forming the second carrier on the first optical element and the second optical element; and forming two separated conductive structures under the first optical element.