Abstract:
An optoelectronic assembly includes a printed circuit board (PCB), a glass carrier positioned upon the PCB and equipped with thereon an active component and an Integrated Circuit (IC) linked to each other via the flip chip technology, an optical waveguide embedded within the PCB, and a ferrule located around the optical waveguide to couple an external optical device thereto for optical transmission therebetween.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to an optoelectronic assembly, and particularly to the optoelectronic assembly with superior heat dissipation. The invention relates to the copending application titled “OPTICAL MODULE ASSEMBLY WITH IMPROVED PRINTED CIRCUIT BOARD” having the same filing date and the same inventors and the same applicant with the instant application. 
         [0003]    2. Description of Related Art 
         [0004]    The traditional optoelectronic assembly includes a printed circuit board (PCB) equipped with the active component, e.g., the vertical-cavity surface-emitting laser (VCSEL) or PIN (p-doped-intrinsic-n-doped) photodetectors, and integrated circuit (IC) linked by the wire:bond. Firstly, the wire-bond is slender with high resistance thereof, thus resulting in high inductance which is not fit for high frequency transmission. Secondly, via such wire-bonds, it is required to have both the active component and IC face up so as to have the heat-dissipation surfaces of both the component and the IC directly seated upon the printed circuit board, thus jeopardizing the efficiencies of the heat dissipation thereof Thirdly, because the active component and IC face up, the corresponding lens is required to be seated upon/above the active component, thus hindering, inspection of the interior size, current and voltage of the active component and the corresponding repairing and adjustment if the VCSEL becomes defective. 
         [0005]    Hence, an improved optoelectronic assembly is desired to overcome the foregoing drawbacks. 
       BRIEF SUMMARY OF THE INVENTION 
       [0006]    Accordingly, an object of the present invention is to provide an improved optoelectronic assembly which is adapted to be used in high frequency transmission and be repaired/adjusted. 
         [0007]    In order to achieve the above-mentioned object, an optoelectronic assembly includes a printed circuit board (PCB), a glass carrier positioned upon the PCB and equipped with thereon an active component and an Integrated Circuit (IC) linked to each other via the flip chip technology, an optical waveguide embedded within the PCB, and a ferrule located around the optical waveguide to couple an external optical device thereto for optical transmission therebetween. 
         [0008]    Other objects, advantages and novel features of the invention will become more apparent from the following detailed description of the present embodiment when taken in conjunction with the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]      FIG. 1  is a perspective view of an optoelectronic assembly of a presently preferred embodiment of the invention; 
           [0010]      FIG. 2  is an exploded perspective view of the optoelectronic assembly of  FIG. 1 ; 
           [0011]      FIG. 3  is another exploded perspective of the optoelectronic assembly of  FIG. 1 ; 
           [0012]      FIG. 4  is a cross-sectional view of the optoelectronic assembly of 
           [0013]      FIG. 1 . 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0014]    Referring to  FIGS. 1 through 4 , an optoelectronic assembly  100  includes a printed circuit board  11  (PCB), a glass carrier  12  mounted upon the PCB  11 , an active component  14  and an Integrated Circuit (IC)  15  mounted upon the glass carrier  12 , and a ferrule  13  mounted upon one end of the PCB  11  for coupling to an optical part (not shown). 
         [0015]    An optical waveguide  115  is embedded within the PCB  11 . The PCB  11  includes a wide portion  111  and the narrow portion  112 . The wide portion includes an upper surface  113  with conductive pads  114  thereon to be an electrical connection port for mating with an electrical connector (not shown). The glass carrier  12  is mounted upon the upper surface  113 . The ferrule  13  is mounted upon the narrow portion  112  as an optional connection port, and includes a receiving space  131  to receive the narrow portion  112  therein, and a pair of alignment holes  132  into which a pair of alignment posts (not shown) of the aforementioned optical part (not shown) are inserted. 
         [0016]    The active component  14  forms opposite upper surface  141  and lower surface  142  wherein the upper surface  141  is for heat dissipation and the lower surface  142  is for mounting to the glass carrier  12 . Similarly, the IC  15  forms opposite upper surface  151  and lower surface  152  wherein the upper surface  151  is for heat dissipation and the lower surface  152  is for mounting to the glass carrier  12 . The glass carrier  12  forms opposite upper surface  121  and lower surface  122  wherein the active component  14  and the IC  15  are mounted upon the upper surface  121  via the solder balls  19 . The active component  14  and the IC  15  are electrically connected with each other via conductive traces  191  printed upon the upper surface  121 . The lower surface  122  is mounted upon the PCB  11  via the solder balls  19 . The solder balls  19  on the lower surface  122  are electrically connected to the corresponding solder balls  10  on the upper surface  121  via the traces or vias within the glass carrier  12 . 
         [0017]    A first lens  16  is unitarily formed within a recess  124  of the glass carrier  12 , and a second lens  17  is molded upon the upper surface  112  of the PCB  11  and vertically communicatively coupling with the optical waveguide  115  via a reflector  18  which is located in a 45-degree recess, which may be formed via the laser processing, around the upper surface  112 . The active component  14 , the first lens  16  and the second lens  17  are aligned together in the vertical direction. During operation, the light from the waveguide  115  hits the second lens  17  via the reflector  18 , and successively hits the first lens  16  and finally enters the active component  14 , e.g., the photo-detector, to convert the optical signals to the electrical signals. The electrical signals are transmitted to the PCB  11  via the IC  15 . Notably, such operation may be implemented vice versa if the active component  14  is the VCSEL. 
         [0018]    In the invention, the active component  14  and the IC  15  are mounted upon the glass carrier  12 , and the glass carrier  12  is mounted upon the PCB  11  wherein the active component  14  and the IC  15  being essentially at the same level, are electrically connected via conductive traces, and the IC  15  and the PCB  11  being essentially vertically offset from each other, are electrically connected via the solder balls  19  and the vias/traces. From a viewpoint, the PCB  11  forms opposite optical side and electrical side respectively coupling to the outer optical part and the outer electrical part, and the glass carrier  12  also forms opposite optical side and the electrical side essentially corresponding to those of the PCB  11  wherein the glass carrier  12  forms an optical transmission path on the optical side for optically connecting the active component  14  with the waveguide  115 , and an electrical transmission path on the electrical side for electrically connecting the IC  15  with the corresponding traces on the PCB  11 . The active component  14  is mounted upon and vertically aligned with the optical side of the glass carrier  12  while the IC  15  is mounted upon and vertically aligned with the electrical side of the glass carrier  12 . 
         [0019]    Compared with the traditional design using the wire-bonds, the invention may lower the value of the inductance for high frequency transmission. In addition, the heat dissipation surfaces of the active component  14  and the IC  15  are the upper surfaces  141  and  151  which is upwardly exposed to an exterior, thus assuring superior heat dissipation. Moreover, when such operation is out of order, it is easy to identify where the defect is located, either on the glass carrier  12  side or on the PCB  11  side, by disassembling the glass carrier  12  from the PCB  11  and inspecting them individually. 
         [0020]    It is to be understood, however, that even though numerous, characteristics and advantages of the present invention have been set fourth in the foregoing description, together with details of the structure and function of the invention, the disclosed is illustrative only, and changes may be made in detail, especially in matters of number, shape, size, and arrangement of parts within the principles of the invention to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.