Abstract:
According to an embodiment of the invention, an optoelectronic device is provided. The optoelectronic device includes: a lead frame having a reflective structure, wherein the reflective structure has an opening; an optoelectronic element disposed in the opening; at least one electrode disposed in the lead frame and electrically connected to the optoelectronic element; a lens disposed on the lead frame and having an adhesive portion having a holding surface, an alignment surface, and an adhesive surface, wherein the adhesive surface has a convex surface or a concave surface; and a covering adhesive layer filling a region defined by the reflective structure, covering the optoelectronic element, and adhering the lens to the lead frame through the adhesive portion of the lens.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This Application claims priority of Taiwan Patent Application No. 101119031, filed on May 29, 2012, the entirety of which is incorporated by reference herein. 
       BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The invention relates to an optoelectronic device, and in particular relates to a light emitting diode device. 
         [0004]    2. Description of the Related Art 
         [0005]    Optical lenses are often disposed on optoelectronic devices for assisting with light transmission. Typically, the optical lens is adhered onto a lead frame through an adhesive layer. 
         [0006]    However, when an optical lens is adhered onto a lead frame, problems of tilt or dislocation may easily arise, which cause differences in light transmission and negatively affect the performance of the optoelectronic device. 
         [0007]    Thus, it is desired to have technique to resolve and/or reduce the above-mentioned problems. 
       BRIEF SUMMARY OF THE INVENTION 
       [0008]    According to an embodiment of the invention, an optoelectronic device is provided. The optoelectronic device includes: a lead frame having a reflective structure, wherein the reflective structure has an opening; an optoelectronic element disposed in the opening; at least one electrode disposed in the lead frame and electrically connected to the optoelectronic element; a lens disposed on the lead frame and having an adhesive portion having a holding surface, an alignment surface, and an adhesive surface, wherein the adhesive surface has a convex surface or a concave surface; and a covering adhesive layer filling a region defined by the reflective structure, covering the optoelectronic element, and adhering the lens to the lead frame through the adhesive portion of the lens. 
         [0009]    According to an embodiment of the invention, an optoelectronic device is provided. The optoelectronic device includes: a lead frame having a reflective structure, wherein the reflective structure has an opening; an optoelectronic element disposed in the opening; at least one electrode disposed in the lead frame and electrically connected to the optoelectronic element; a lens disposed on the lead frame and having an adhesive portion having a holding surface, an alignment surface, and an adhesive surface, wherein the adhesive surface has an adhesive sidewall and an adhesive bottom surface; and a covering adhesive layer filling a region surrounded by the reflective structure and covering the optoelectronic element, wherein the lens is adhered to the lead frame through the adhesive portion of the lens. 
         [0010]    According to an embodiment of the invention, a method for forming an optoelectronic device is provided. The method includes: providing a lead frame; disposing an optoelectronic element on the lead frame; filling a covering adhesive layer in a region surrounded. by the reflective structure, wherein the covering adhesive layer covers the optoelectronic element; disposing a lens on an opening of the lead frame and the covering adhesive layer, wherein the lens has a holding surface, an alignment surface and an adhesive surface, and the adhesive surface has a convex surface or a concave surface; and curing the covering adhesive layer. 
         [0011]    According to an embodiment of the invention, a method for forming an optoelectronic device is provided. The method includes: providing a lead frame; disposing 
         [0012]    an optoelectronic element on the lead frame; filling a covering adhesive layer in a region surrounded by the reflective structure, wherein the covering adhesive layer covers the optoelectronic element; disposing a lens on an opening of the lead frame and the covering adhesive layer, wherein the lens has a holding surface, an alignment surface and an adhesive surface, wherein the adhesive surface has an adhesive sidewall and an adhesive bottom surface; and curing the covering adhesive layer. 
         [0013]    A detailed description is given in the following embodiments with reference to the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0014]    The present invention can be more fully understood by reading the subsequent detailed description and examples with references made to the accompanying drawings, wherein: 
           [0015]      FIGS. 1A-1C  are cross-sectional views of a manufacturing process of an optoelectronic device according to an embodiment of the present invention; 
           [0016]      FIG. 2  is a cross-sectional view of a lens according to an embodiment. of the present invention; and 
           [0017]      FIGS. 3A-3C  are cross-sectional views of optoelectronic devices according to embodiments of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0018]    The following description is of the best-contemplated mode of carrying out the invention. This description is made for the purpose of illustrating the general principles of the invention and should not be taken in a limiting sense. The scope of the invention is best determined by reference to the appended claims. 
         [0019]    The manufacturing method and method for use of the embodiment of the invention are illustrated in detail as follows. It is understood that the following disclosure provides many different embodiments, or examples, for implementing different features of the invention. Specific examples of components and arrangements are described below to simplify the present disclosure. These are, of course, merely examples and are not intended to be limiting. In addition, the present disclosure may repeat reference numbers and/or letters in the various examples. This repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed. Furthermore, descriptions of a first layer “on,” “overlying,” (and like descriptions) a second layer, include embodiments where the first and second layers are in direct contact and those where one or more layers are interposing the first and second layers. 
         [0020]      FIGS. 1A-1C  are cross-sectional views of a manufacturing process of an optoelectronic device according to an embodiment of the present invention. As shown in  FIG. 1A , the optoelectronic device has a lead frame  10 , and the lead frame  10  includes a reflective structure  100 . The reflective structure  100  can include plastics, silicone resin, epoxy resin, multiple coatings, polymer material, ceramic material, semiconductor material, metal material, or combinations thereof. The reflective structure  100  has an opening. 
         [0021]    The optoelectronic device includes an optoelectronic element  110  disposed in the opening of the reflective structure  100 . The optoelectronic element  110  can be a light emitting element (e.g. a light emitting diode) or a light sensing element. Taking a light emitting diode as an example, the optoelectronic element  110  has a P-type electrode and a N-type electrode (not shown), wherein the P-type electrode and the N-type electrode are electrically connected to conductive regions  102   a  and  102   b  of the lead frame  10  through the conductive wires  112   a  and  112   b  (e.g. by wire bonding or flip chip bonding), respectively. The conductive regions  102   a  and  102   b  are electrically connected to the electrodes  104   a  and  104   b  disposed on the lead frame  10  through conductive wires (not shown). 
         [0022]    Then, as shown in  FIG. 1B , the covering adhesive layer  140  is filled in a region surrounded by the reflective structure  100  to cover the optoelectronic element  110 . The covering adhesive layer  140  has good light transmittance and good adhesion. The covering adhesive layer  140  can include silicone resin, epoxy resin, glass, or combinations thereof. The covering adhesive layer  140  can include other suitable transparent polymer materials. The covering adhesive layer  140  can be used to protect the optoelectronic element  110  and to adhere to and fix the lens  13 , which will be installed in a subsequent process. 
         [0023]    The lens  13  includes silicone resin, epoxy resin, glass, or combinations thereof. Alternatively, the lens  13  can include other suitable transparent materials. The lens  13  includes an output light portion  131 , and the output light portion  131  has a convex profile (or a convex shape) or a concave profile (or a concave shape). The lens  13  includes an adhesive portion, and the adhesive portion has a holding surface  132 H, an alignment surface  132 S and an adhesive surface  132 P. 
         [0024]    Then, the lens  13  is disposed on the reflective structure  100 , and the lens  13  can be embedded in and fixed to the covering adhesive layer  140 , as shown in  FIG. 1C . After the disposing of the lens  13 , the covering adhesive layer  140  can optionally be cured. The curing of the covering adhesive layer  140  further includes a step of performing a light curing process, a thermal curing process, a room-temperature curing process, or combinations thereof to the covering adhesive layer  140 . 
         [0025]    The disposing of the lens  13  on the reflective structure  100  includes the steps of contacting the holding surface  132 H of the lens  13  with a surface  100 T of the reflective structure  100 , and putting the alignment surface  132 S into the opening along a sidewall  100 R of the reflective structure  100 . 
         [0026]    As shown in  FIG. 1C , the holding surface  132 H of the lens  13  is on the surface  100 T of the reflective structure  100 . The holding surface  132 H can be in direct contact with the surface  100 T of the reflective structure  100 . Alternatively, other material layers can be formed between the holding surface  132 H and the surface  100 T of the reflective structure  100 . The reflective structure  100  can support the holding surface  132 H so as to maintain the lens  13  in a suitable position. The holding surface  132 H can be an annular plane. A maximum width D 1  of the holding surface  132 H is greater than a width D L  of the opening of the reflective structure  100 . The holding surface  132 H can be substantially parallel to the surface  100 T of the reflective structure  100 . A maximum width D 2  of the adhesive surface  132 P is less than a width D L  of the opening of the reflective structure  100 . 
         [0027]    The alignment surface  132 S of the lens  13  can be used to help the alignment of the lens  13 . The lens  13  moves downwardly along the sidewall  100 R of the reflective structure  100 . The alignment surface  132 S can be substantially parallel to the sidewall  100 R of the reflective structure  100 . The alignment surface  132 S can be in direct contact with the sidewall  100 R of the reflective structure  100 . Alternatively, other material layers can be formed between the alignment surface  132 S and the sidewall  100 R of the opening. The alignment surface  132 S connects the holding surface  132 H. 
         [0028]    The adhesive surface  132 P of the lens  13  extends from the alignment surface  132 S to the optoelectronic element  110 . The adhesive surface  132 P is in direct contact with the covering adhesive layer  140 . The adhesive surface  132 P includes a convex surface or a concave surface. The adhesive surface  132 P of the lens  13  helps the lens  13  to be pressed into the covering adhesive layer  140  and avoids and/or reduces the generation of bubbles in the covering adhesive layer  140 . Thus, light can be successfully transmitted out from the optoelectronic element  110 , or light can be successfully transmitted from the environment into the optoelectronic element  110 . 
         [0029]      FIG. 2  is a cross-sectional view of a lens according to an embodiment of the present invention, wherein the same or similar reference numbers are used to designate the same or similar elements. The lens  13  of the embodiment of  FIG. 2  is similar to the lens  13  of the embodiment of  FIG. 1C  except that the adhesive surface  132 P of the lens  13  of  FIG. 2  further includes an adhesive sidewall  132 P 1  and an adhesive bottom surface  132 P 2 . The adhesive bottom surface  132 P 2  is substantially a plane, a convex surface, or a concave surface. The lens  13  shown in  FIG. 2  can replace the lens  13  of the embodiment of  FIG. 1C . In this case, the adhesive bottom surface  132 P 2  is substantially parallel to the surface  100 T of the reflective structure  100 , but the invention is not limited thereto. 
         [0030]      FIGS. 3A-3C  are cross-sectional views of optoelectronic devices according to other embodiments of the present invention, wherein same or similar reference numbers are used to designate same or similar elements. In the embodiments, a plurality of optical wavelength converting particles and/or a plurality of optical diffusion particles can be introduced into the optoelectronic device. For example, particles  300  are disposed in the lens  13 , as shown in  FIG. 3A . Alternatively, the particles  300  can be disposed in the covering adhesive layer  140 , as shown in  FIG. 3B . Alternatively, the particles  300  can be disposed in the lens  13  and the covering adhesive layer  140 , as shown in  FIG. 3C . The suitable optical wavelength converting particles include, for example, yttrium aluminum garnet (YAG) fluorescence powder, silicate fluorescence powder, terbium aluminum garnet (TAG) fluorescence powder, oxide fluorescence powder, nitride fluorescence powder, aluminum oxide fluorescence powder, fluorescence powder and materials capable of converting optical wavelengths, or combinations thereof The suitable optical diffusion particles include, for example, silicon dioxide particles, aluminum oxide particles, calcium fluoride particles, calcium carbonate particles, barium sulfate particles, particles capable of diffusing light, or combinations thereof The lens  13  of the embodiment of  FIG. 2  can be used to replace the lens of the embodiments of  FIGS. 3A-3C . 
         [0031]    The lens of the optoelectronic device of the embodiments of the invention has a specific adhesive portion, which can facilitate the self-alignment between the lens and the covering adhesive layer during the bonding of the lens to the covering adhesive layer, and thus the tilt of the lens and the mismatch of the lens and the covering adhesive layer can be reduced and/or be avoided, which helps the lens to be positioned accurately and set firmly onto the optoelectronic element. Moreover, the transmission error of light can be reduced, the performance of the device can be improved, the manufacturing process can be simplified, and the manufacturing cost can be reduced. Furthermore, the generation of bubbles in the covering adhesive layer can be effectively avoided by the design of the convex surface or the concave surface of the bottom of the lens so as to improve the performance of the optoelectronic device. 
         [0032]    While the invention has been described by way of example and in terms of the preferred embodiments, it is to be understood that the invention is not limited to the disclosed embodiments. On the contrary, it intended to cover various modifications and similar arrangements (as would be apparent to those skilled in the art). Therefore, the scope of the appended claims should he accorded the broadest interpretation so as to encompass all such modifications and similar arrangements.