Patent Publication Number: US-6714714-B1

Title: Butterfly package pallet

Description:
BACKGROUND OF THE INVENTION 
     Hermetic packages are used in fiber optic systems to protect opto-electronic components from the environment. During manufacturing, the opto-electronic components are typically installed on a bench or submount, which is installed within the package. Optical fiber is typically inserted through a fiber feedthrough and secured onto the submount relative to the opto-electronic components. Preliminary testing may be performed in which the components are energized or their responses sampled to ensure that the opto-electronics are operating properly. Moreover, it may be necessary to energize active components or sample the responses of detectors as part of active alignment processes. 
     Once the manufacturing steps have been completed and the opto-electronic circuit is configured, the package is typically hermetically sealed in a lid sealing operation. Further, the ferrules around the optical fibers are further sealed. 
     Typically, in the manufacturing lines, the fiber optic systems are transported on multi-package trays. These trays typically have stops that prevent the packages from sliding during transportation between manufacturing steps. 
     SUMMARY OF THE INVENTION 
     One problem associated with these conventional tray systems surrounds the fact that many manufacturing steps are required to complete the fiber optic system. Further, the package must be transported numerous times between various machines. With each manufacturing step, the opto-electronic package must be manually removed from the tray and installed on a machine or other fixture for the associated manufacturing step. 
     The present invention is directed to pallet. It has provisions for supporting an opto-electronic package on a frame. Punched openings are provided through the frame to enable mechanical access to the opto-electronic package from below the frame. As a result, the opto-electronic package need not be directly manipulated by an operator. Instead, the package can be carried on the pallet, which is then installed directly on top of a given machine. The machine mechanically engages the package via the punched openings. 
     In general, according to one aspect, the invention features an opto-electronic package pallet. It comprises a frame having a punched opening for enabling mechanical access from below the frame to an opto-electronic package supported by the frame. In one embodiment, non-conductive shoulders are connected to the frame for supporting the opto-electronic package above the frame. 
     According to a preferred implementation, a fiber reel is also provided on the frame for holding a coil or length of optical fiber. Such fiber, typically in the form of a fiber pigtail, is typically inserted into the package, through a feed through, and connected to a submount or bench within the package as part of the manufacturing process. 
     According to further aspects of the preferred embodiment, a lead access punched opening is also provided in the pallet for enabling electrical connections to electrical leads of the opto-electronic package from below the frame. Typically, two lead access openings are provided for enabling access to two sets of butterfly electrical leads on the package. 
     According to another aspect of the preferred embodiment, standoffs are also provided to enable stacking of the pallets, one on top of the other. To enable a secure inter-pallet connection, standoff engagement slots are also preferably provided in each pallet. 
    
    
     The above and other features of the invention including various novel details of construction and combinations of parts, and other advantages, will now be more particularly described with reference to the accompanying drawings and pointed out in the claims. It will be understood that the particular method and device embodying the invention are shown by way of illustration and not as a limitation of the invention. The principles and features of this invention may be employed in various and numerous embodiments without departing from the scope of the invention. 
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In the accompanying drawings, reference characters refer to the same parts throughout the different views. The drawings are not necessarily to scale; emphasis has instead been placed upon illustrating the principles of the invention. Of the drawings: 
     FIG. 1 is a perspective view of a pallet holding an opto-electronic package, according to the present invention; 
     FIG. 2 shows a pallet with an opto-electronic package, which has been installed on a machine, illustrating the mechanical access to the package that is allowed by the pallet; 
     FIG. 3 is a perspective view of a pallet, with an opto-electronic package and a fiber reel for holding a coil or length of optical fiber; and 
     FIG. 4 is a perspective view showing multiple, stacked pallets, each holding a respective opto-electronic package. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIG. 1 shows a butterfly package pallet, which has been constructed according to the principles of the present invention. 
     Generally, the pallet  100  is shown holding an opto-electronic package  10 . In the specific illustrated embodiment, the opto-electronic package  10  is a butterfly package with electrical leads  12  extending from the package sidewalls, on either side of the package. 
     In the illustrated package, fiber ferrules  14  are also provided in fiber feedthroughs to accommodate passage of a fiber pigtail end into the package. Typically, the end of the pigtail is attached down onto a submount or bench that is to be installed within the package prior to a lid sealing operation. 
     The package further has a base  18 . Typically, this base is used for mechanically securing the package  10  into a printed circuit board or other mechanical support during its final installation. 
     The pallet  100  comprises a frame portion  112 . In the present embodiment, the frame portion  112  is manufactured from a stainless steel stamped sheet. The specific illustrated embodiment has an octagonal shape. This allows for the dense packing of the pallets  100 , next to each other. 
     According to the invention, a mechanical access opening  110 A,  110 B is formed in the frame  100 . This allows the package to be mechanically engaged or grabbed from below the frame. 
     Further, according to the preferred embodiment, lead access openings  114 A are also provided in the frame  112 . These allow electrical access to the leads  12  of the package  10 , preferably from below the pallet  100  during manufacturing operations. 
     A mechanism is also preferably provided for stacking successive pallets, one on top of each other. In the illustrated embodiment, standoffs  118  are provided. These standoffs  118  have engagement tongues  120 . When stacked, the engagement tongues mate with the standoff slots  122  of an adjoining pallet  100 . 
     In one embodiment, two shoulders  150 A,  150 B, manufactured preferably from a non-conducting material such as a resin or ceramic, are attached, such as bonded, to the top surface of the pallet  112 . The leads  12  of the package  10  rest on these shoulders, preferably in slots  152  so that the package is held above the top plane of the frame  112 . This helps to protect the electronic components from damage from electrostatic discharge. 
     FIG. 2 shows a pallet  100  holding an opto-electronic package  10 , which has been installed on a manufacturing machine chuck  50 . Typically, clamp members  52  of the chuck  50  project or extend up through the both sides  110 A,  110 B of the access opening to engage the support base  18  of the package  10 . 
     Further, according to the preferred implementation, lead contact arrays  54 A,  54 B extend through the lead access openings  114 A,  114 B to mechanically and electrically engage the leads  12  of the package  10 . 
     As a result, according to the preferred embodiment, after installation on a machine chuck  50 , the package  10  is mechanically attached to the chuck with clamps while the leads  12  of the package are engaged by the lead contact arrays  54 A,  54 B, allowing energization of the active devices within the package or sampling of responses from detectors, for example. 
     FIG. 3 shows a pallet  100  in which a fiber reel  210  has been attached to the frame  112 . Specifically, the reel  210  is generally circular with lip portions  212  extending upward from the reel to hold a coiled length of optical fiber extending around an inner periphery of the lip portions  212 . This allows for the containment of the fiber pigtail in proximity to the package  10  during a pigtailing operation, and thereafter. Further, the slot regions  214  are provided between the lips  212  of the reel  210  allow for the manipulation of the fiber pigtail for insertion into or removal from the reel. 
     Finally, FIG. 4 is a perspective view of multiple pallets  100  stacked one on top of each other. In each case, the standoffs  118  extend downward from the respective package frame  112  so that the engagement tongues  120  mate with the standoff slots  122  of an adjoining pallet  100 . 
     While this invention has been particularly shown and described with references to preferred embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the scope of the invention encompassed by the appended claims.