Abstract:
An optical alignment device is provided comprising a base portion extending the length of the alignment device, a substantially horizontal package mounting portion coupled to the base portion, and a component retaining portion coupled to the base portion.

Description:
CROSS REFERENCE TO RELATED APPLICATION  
       [0001]    The present application claims priority to and the benefit of the following U.S. Provisional Patent Application:  
         [0002]    Serial No. 60/356,776 filed Feb. 15, 2002  
         [0003]    The foregoing provisional application is incorporated by reference herein in its entirety. 
     
    
     
       BACKGROUND OF THE INVENTION  
         [0004]    A. Field of the Invention  
           [0005]    The invention is directed to optical component attachment methods and apparatuses, and more particularly, to an apparatus to support optical component(s) attachment to packages that traditionally require a coaxial attachment system.  
           [0006]    B. Background of the Invention  
           [0007]    Coaxial alignment and attachment of an optical component to a package is typically performed with a symmetrically placed beam system such that each beam is equally positioned about a coaxial center. Namely, a three-beam system at minimum is generally needed to achieve this. Special tooling such as coaxial alignment stage, grippers and special fixtures are required for coaxial attachment to properly align three-beam systems and attach the components to the package, due to the heightened need for access to an even point about the coaxial center. A two-beam system is typically configured such that the beams are 180° apart. This is usually employed if only the top half of the device is accessible for assembly. A three beam system is configured such that the beams are 120° apart. A three beam system is used when the device being assembled has access all around. This requires the system to position the package upright, and requires a complex system of tooling and fixtures. Furthermore, this process also does not lend well to post attachment alignment.  
           [0008]    Alignment and attachment of optical components to packages such as a butterfly style require a two beam system (if laser welding is emphasized) with two dispensers (if epoxy is employed) in a single side (e.g., top-down) configuration. Top-down is generally the only way to have unobtrusive view of the inside of the package or device being assembled. This is the conventional way to align optical components inside a butterfly package. A horseshoe or equivalently shaped clip is typically used to secure the optical components to the package. This requires the use of additional tooling to hold the clip in place, to ensure that it is seated, and in contact with the surface that it is being attached to.  
         SUMMARY OF THE INVENTION  
         [0009]    According to one aspect of the present invention, an optical alignment device is provided comprising a base portion extending the length of the alignment device, a substantially horizontal package mounting portion coupled to the base portion, and a component retaining portion coupled to the base portion.  
           [0010]    According to another aspect of the present invention, the component retaining portion is substantially vertical with respect to the substantially horizontal package mounting portion.  
           [0011]    According to another aspect of the present invention, the substantially horizontal package mounting portion comprises a plurality of substantially horizontal feet, each of the feet extending substantially horizontally from a top edge of the base portion. Preferably, each of the substantially horizontal feet has a foot length in the range of about 0.5 mm to about 2 mm.  
           [0012]    According to another aspect of the present invention, each of the substantially horizontal feet is formed by one of Electrical Discharge Machining (“EDM”), laser cutting, and stamping and press fitting. Most preferably, each of the substantially horizontal feet is formed by stamping and press fitting.  
           [0013]    According to another aspect of the present invention, the substantially horizontal package mounting portion is attached to a package. Preferably, each of the substantially horizontal feet is attached to the package by one of welding, epoxy, and solder. Most preferably, each of the substantially horizontal feet is attached to the package by laser welding.  
           [0014]    According to another aspect of the present invention, the component retaining portion comprises a plurality of side walls, each of the side walls extending from a top edge of the base portion. Preferably, each of the side walls has a height in the range of about 0.5 mm to about 2 mm.  
           [0015]    According to another aspect of the present invention, the base portion has a substantially semicircular cross-section extending the length of the alignment device. Preferably, the base portion has a radius in the range of about 0.4 mm to about 2 mm.  
           [0016]    According to another aspect of the present invention, the optical alignment device is made of a material comprising at least one of stainless steel, kovar, invar, and nickel. Preferably, the optical alignment device is made of nickel.  
           [0017]    According to yet another aspect of the present invention, a method of coaxial alignment is provided comprising the steps of positioning an optical component in an optical alignment device, attaching a substantially horizontal package mounting portion to a package, and attaching the optical component to a vertical component retaining portion. The optical alignment device comprises a base portion extending the length of the alignment device, the substantially horizontal package mounting portion coupled to the base portion, and the substantially vertical component retaining portion coupled to the base portion.  
           [0018]    According to another aspect of the present invention, the method further comprises a step of adjusting at least one of the position and alignment of the optical component within the optical alignment device after attaching the substantially horizontal package mounting portion to a package.  
           [0019]    According to yet another aspect of the present invention, a coaxial alignment and attachment clip for single side optical component attachment is provided comprising a component loading section, and a package fixation section attached to the component loading section for fixing a package to the clip. The component loading section allows the optical component to be adjustable by at least one of: (1) rotationally about a central axis of the optical component; (2) slidably along a length of the optical component; and (3) slidably along a height of the optical component.  
           [0020]    It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only, and are not restrictive of the invention as claimed.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0021]    These and other features, aspects and advantages of the present invention will become apparent from the following description, appended claims, and the accompanying exemplary embodiments shown in the drawings, which are briefly described below and which constitute part of this specification.  
         [0022]    [0022]FIG. 1 is a perspective view of an attachment clip according to an embodiment of the present invention.  
         [0023]    [0023]FIG. 2 a  depicts a front view of an attachment clip according to an embodiment of the present invention.  
         [0024]    [0024]FIG. 2 b  depicts a top view of an attachment clip according to an embodiment of the present invention.  
         [0025]    [0025]FIG. 2 c  depicts a side view of an attachment clip according to an embodiment of the present invention.  
         [0026]    [0026]FIG. 3 depicts a top view of an attachment clip with welding spots indicated according to an embodiment of the present invention.  
         [0027]    [0027]FIG. 4 depicts a side view of an attachment clip with a vertical side wall indicated according to an embodiment of the present invention.  
         [0028]    [0028]FIG. 5 depicts a perspective view of an attachment clip with vertical wall height b and horizontal feet height a according to an embodiment of the present invention.  
         [0029]    [0029]FIG. 6 is a perspective view of an attachment clip according to an embodiment of the present invention.  
     
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS  
       [0030]    Reference will now be made in detail to presently preferred embodiments of the invention. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts. Throughout the description, the term “component” will be used to describe any part which can be aligned using the alignment clip of the present invention. Preferably, a component includes an optical component, such as lenses and optical fibers. The present invention can also be used, however, to align a plurality of components (i.e., an assembly).  
         [0031]    The inventors have discovered a novel attachment clip that can be used to hold an optical component and/or assembly. The novel design allows for coaxial attachment of components by using a more flexible and economical single side (e.g., top-down) attachment system. This attachment clip is suitable for active alignment and attachment of the optical assembly (or component). The attachment process may include, but is not limited to soldering, epoxying, and welding. The attachment clip allows for coaxial type alignment (i.e., along the axis of the clip) with a top-down configuration. Furthermore, the attachment clip allows for pressure to be applied by the optical assembly in order to make contact between a plurality of feet and a package, which may be necessary for some methods of attaching the feet to the package.  
         [0032]    A first embodiment of an attachment clip  100  according to the present invention is shown in the views of FIGS.  1 - 5 . The attachment clip  100  includes two or more substantially vertical side walls  20 , a base portion  30 , and a plurality of substantially horizontal feet  10 . As shown in the various views of FIG. 2, the attachment clip  100  allows the optical component  200  to be manipulated in the: X and roll (FIG. 2 a ), Z and θ (FIG. 2 b ), Y and φ (FIG. 2 c ) directions and unlimited 360° roll. It should be appreciated that attachment of the clip  100  to the package sets the X and θ parameters. As shown in FIG. 3, the clip  100  is preferably attached to the package by laser welding  310  the substantially horizontal feet  10  to the package. However, as would be readily apparent to one of ordinary skill in the art after reading this disclosure, other attachment schemes are also possible.  
         [0033]    The Y, Z, φ, and roll parameters can typically still be adjusted even after the clip  100  is attached to the package. As shown in FIG. 4, the substantially vertical side walls  20  provides for increased allowable vertical translation of the optical component  200 . The design of the attachment clip  100  is such that any shifting due to movement in the attachment process can be compensated for to regain optimal position and alignment.  
         [0034]    The attachment clip  100  may be adjusted to accommodate various optical components  200  and/or assemblies. The attachment clip  100  may include any number of substantially horizontal feet  10  and substantially vertical side walls  20 . It should also be appreciated that the substantially horizontal feet  10  are preferably horizontal, but may also be positioned at an angle if desired. Similarly, the substantially vertical side walls  20  are preferably vertical, but may also be angled inward or outward if desired.  
         [0035]    Furthermore, the clip  100  is not limited to circular components as shown in the Figures. The clip  100  as shown in FIG. 5 has a base portion  30  with a substantially circular cross-section with radius R. However, the cross-section could be rectangular or ovular in shape. As would be readily apparent to one of ordinary skill in the art after reading this disclosure, the feet dimension (a) and the vertical wall dimension (b) depicted in FIG. 5 can be adjusted in order to increase or decrease the absolute travel of the component. Thus, the dimensions a, b, and R may vary based on the size of the component  200  and the amount of travel desired. Preferably, the substantially horizontal feet  10  dimension a is in the range of about 0.5 mm to about 2 mm. Preferably, each of the substantially vertical side walls  20  has a height b in the range of about 0.5 mm to about 2 mm. Preferably, the base  30  has a radius in the range of about 0.4 mm to about 2 mm.  
         [0036]    The attachment clip  100  can be used to hold an optical component  200 . Once in the clip  100 , the optical component  200  can be translated and/or rotated in order to find the optimal position. Once an optimal position is achieved, the optical component can be fixed to the clip  100 . For example, the clip  100  and the optical component  200  could be laser welded in place. This would preferably utilize a two-beam-top-down laser head configuration. The two beam approach is configured to have the beams 180° apart and the welding is done symmetrically. In such a case, the optical clip  100  should be fabricated of a weldable material, such as Kovar. Alternatively, the clip  100  may comprise invar, stainless steel, or nickel.  
         [0037]    The attachment clip  100  allows for a coaxial type of alignment/attachment but utilizes a top-down configuration. The dimensions, location, and number of substantially horizontal feet  10  and substantially vertical side walls  20  are adjustable to suit the needs of various optical assemblies and/or components  200 . The substantially vertical side walls  20  on the clip  100  allow for vertical movement of the optical component  200  above and below a desired plane. The substantially horizontal feet  10  provide mechanical stability for the clip  100  and also horizontal movement. The clip  100  allows for alignment and attachment without the need for additional tooling to keep the clip  100  in place during the attachment process. Depending on the geometrical shape and mass of the optical components  200  that the clip  100  supports, the locations of the substantially horizontal feet  10  and substantially vertical side walls  20  can be switched and otherwise adjusted to allow for optical mechanical stability. The attachment clip  100  allows for a method of coaxial type attachment without the need for a coaxial attachment system.  
         [0038]    The foregoing description of a preferred embodiment of the invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed, and modifications and variations are possible in light of the above teachings or may be acquired from practice of the invention.  
         [0039]    One such exemplary variation is shown in the perspective view of FIG. 6. FIG. 6 shows an optical clip  600  with vertical side walls  620 , a plurality of horizontal feet  610 , and a base portion  630 . As shown, the vertical side walls  620  have a trapezoidal shape rather than the rectangular shape of previous embodiments. Alternatively, the vertical side walls  610  and/or the horizontal feet  610  may have a rounded/circular shape and/or other variations as would be readily apparent to one skilled in the art after reading this disclosure.  
         [0040]    The embodiments were chosen and described in order to explain the principles of the invention and its practical application to enable one skilled in the art to utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined the claims appended hereto, and their equivalents.