Abstract:
UV curing of adhesives with light beam shaping utilizes a spot curing process that focuses a limited amount of UV light onto a target area, such as glue dots. A focusing lens may be used to direct the UV light beam to the target area. The target areas have different geometrical shapes, and the UV light is advantageously concentrated in a more efficient manner. Beam-shaping optics or lenses are used to facilitate re-shaping and re-defining the UV-light beam. The UV beam may be defined and limited to a rectangular spot to improve the spot process quality and efficiency.

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S) 
       [0001]    The present application is a divisional from U.S. patent application Ser. No. 11/946,956, filed Nov. 29, 2007, entitled “SYSTEM, METHOD AND APPARATUS FOR ULTRAVIOLET CURING OF ADHESIVES WITH LIGHT BEAM SHAPING IN DISK DRIVE MANUFACTURING,” naming inventors Iraj Kavosh and Russell D. Moates, which is incorporated by reference herein in its entirety. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Technical Field 
         [0003]    The present invention relates in general to curing adhesives and, in particular, to an improved system, method, and apparatus for ultraviolet curing of adhesives with light beam shaping. 
         [0004]    2. Description of the Related Art 
         [0005]    In the prior art, some manufacturing materials are applied as fluids and then cured (i.e., set or hardened) with light or heat treatment processes. For example, some liquid adhesives are cured with ultraviolet (UV) light. These classes of materials are widely utilized in various types of industries. 
         [0006]    In the production of hard disk drives, one such application is the head stack assembly (HSA). HSA assembly utilizes a liquid or gel adhesive during the fabrication process to join some of the components. In one example, small dots of glue are used to attach the integrated lead suspension (ILS) to the actuator comb in order to improve the dynamics of the disk drive. The assembly process typically utilizes “oven flood UV curing” to set the liquid glue dots, which comprises indiscriminately flooding an entire array of the assemblies with UV light. Although this type of processing for UV-cured adhesives is workable, an improved solution that more selectively cures adhesives would be desirable. 
       SUMMARY OF THE INVENTION 
       [0007]    Embodiments of a system, method, and apparatus for curing of adhesives with light beam shaping are disclosed. The invention may comprise a UV-spot curing process that focuses a limited amount of UV light onto a target area, such as glue dots. A focusing lens may be used to direct the UV light beam to the target area. In some embodiments, the target areas have different geometrical shapes, and the UV light is advantageously concentrated in a more efficient manner. 
         [0008]    In one approach beam-shaping optics or lenses are used to facilitate re-shaping and re-defining the UV-light beam. For example, the UV beam may be defined and limited to a rectangular spot to improve the spot process quality and efficiency. Utilizing beam-shaping optics to shape and define a focused light beam in glue dot curing processes enhances the quality efficiency and effectiveness of the manufacturing process, as well as the efficiency in utilizing UV power. 
         [0009]    The foregoing and other objects and advantages of the present invention will be apparent to those skilled in the art, in view of the following detailed description of the present invention, taken in conjunction with the appended claims and the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]    So that the manner in which the features and advantages of the present invention, which will become apparent, are attained and can be understood in more detail, more particular description of the invention briefly summarized above may be had by reference to the embodiments thereof that are illustrated in the appended drawings which form a part of this specification. It is to be noted, however, that the drawings illustrate only some embodiments of the invention and therefore are not to be considered limiting of its scope as the invention may admit to other equally effective embodiments. 
           [0011]      FIG. 1  is a schematic isometric view of one embodiment of a light and lens assembly constructed in accordance with the invention; 
           [0012]      FIG. 2  is an isometric view of one embodiment of adhesive-joined assembly that was cured by the light and lens assembly of  FIG. 1  and is constructed in accordance with the invention; 
           [0013]      FIG. 3  is a schematic diagram of one embodiment of a disk drive constructed in accordance with the invention; and 
           [0014]      FIG. 4  is a high level flow diagram of one embodiment of a method constructed in accordance with the invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0015]    Referring to  FIGS. 1-4 , embodiments of a system, method and apparatus for curing adhesives with light beam shaping are disclosed. As schematically depicted in  FIG. 1 , one embodiment of the invention comprises a system for shaping a light beam, such as ultraviolet (UV) light. The system includes a light source  11  for emitting light  13 . A light guide  15  having an inlet end  17  receives the light  13  from the light source  11 , and an outlet end  19  for emitting light  21  conveyed through the light guide  15 . As shown in  FIG. 1 , the emitted light  21  may diverge from outlet end  19 . 
         [0016]    A lens assembly  31  is located adjacent to the outlet end  19  of the light guide  15 . The lens assembly  31  is provided for collimating the emitted light and forming a desired geometric-shaped light beam  33  (e.g., a rectangle, square, etc.). The lens assembly  31  comprises a plurality of lenses including, e.g., a spherical collimating lens  35  and at least one other lens element  37 ,  39  (e.g., two shown). The spherical collimating lens  35  is located closest to the outlet end  19 . The light guide  15  may emit the diverging beam  21  such that it passes through the spherical collimating lens  35  prior to passing through the other lens elements  37 ,  39 . 
         [0017]    Again as shown in  FIG. 1 , the lens elements  37 ,  39  may comprise a pair of cylindrical lenses. Each of the cylindrical lenses  37 ,  39  may be provided with a convex leading surface  41  and a planar trailing surface  43  that are normal to an axis  45  of the emitted light. In addition, the cylindrical lenses  37 ,  39  may be rotated and positioned 90 degrees out of phase relative to each other as illustrated. Each of the lenses that form the lens assembly  31  may be varied in distance relative to each other, the outlet end  19 , and the target struck by beam  33  to alter the pattern aspect ratio or other features of the invention. Position, focal length, and power of each lens may be varied to achieve a desired shape or size. 
         [0018]    The invention has many useful applications, such as a method of assembling hard disk drive components as shown in  FIG. 2 . For example, a plurality of integrated lead suspensions  51  (ILS) may be assembled to an actuator comb  53  with adhesive drops  55 . The adhesive drops may be sized and shaped (e.g., circular, oval, etc.) according to the application, but must be cured to complete the assembly. Typically, the adhesive drops  55  are applied in a shaped pattern  57  (e.g., a rectangle). The adhesive drops  55  may be cured individually or simultaneously in their respective patterns  57 . 
         [0019]    In one embodiment of the method ( FIG. 4 ), the process begins as indicated and comprises positioning an actuator comb (e.g., arms) adjacent to an integrated lead suspension (ILS) (step  61 ); applying a plurality of adhesive drops in a pattern to the actuator comb and ILS such that that adhesive drops extend between the actuator comb and ILS to form an assembly (step  63 ); providing light from a light source and directing the light through a light guide having an outlet end for emitting light conveyed through the light guide (step  65 ); and passing the emitted light through a lens assembly located between the outlet end and the assembly for collimating the emitted light and forming a desired geometric-shaped light beam that is contoured to the shape of the pattern of adhesive drops to cure the adhesive drops and form a bond between the actuator comb and the ILS (step  67 ), before ending as indicated. 
         [0020]    In other embodiments, the method may comprise providing the lens assembly as a plurality of lenses, as a spherical collimating lens and at least one other lens element, such as a pair of cylindrical lenses. The collimating lens may be located adjacent to the outlet end such that the light guide emits a diverging beam that passes through the collimating lens prior to passing through said at least one other lens element. 
         [0021]    Each of the cylindrical lenses may be provided with a convex leading surface and a planar trailing surface that are normal to an axis of the emitted light. The method may further comprise rotating and positioning the cylindrical lenses 90 degrees out of phase relative to each other. In addition, the light source may emit UV light, and the desired geometric-shaped light beam may comprise a rectangular light beam. 
         [0022]    Referring now to  FIG. 3 , a schematic drawing of one embodiment of an information storage system comprising a magnetic hard disk file or drive  111  for a computer system is shown and is constructed in accordance with the invention. Drive  111  has an outer housing or base  113  containing at least one magnetic disk  115 . Disk  115  is rotated by a spindle motor assembly having a central drive hub  117 . An actuator  121  comprises one or more parallel actuator arms  125  in the form of the comb  53  that is pivotally mounted to base  113  about a pivot assembly  123 . A controller  119  is also mounted to base  113  for selectively moving the comb of arms  125  relative to disk  115 . 
         [0023]    In the embodiment shown, each arm  125  has extending from it at least one (e.g., eight shown in  FIG. 2 ) cantilevered load beam and suspension  51 , and is assembled as described above. A magnetic read/write transducer or head is mounted on a slider  129  and secured to a flexure that is flexibly mounted to each suspension  51 . The read/write heads magnetically read data from and/or magnetically write data to disk  115 . The level of integration called the head gimbal assembly is the head and the slider  129 , which are mounted on suspension  51 . The slider  129  is usually bonded to the end of suspension  51 . The head is typically formed from ceramic or intermetallic materials and is pre-loaded against the surface of disk  115  by suspension  51 . 
         [0024]    Suspensions  127  have a spring-like quality which biases or urges the air bearing surface of the slider  129  against the disk  115  to enable the creation of the air bearing film between the slider  129  and disk surface. A voice coil  133  housed within a voice coil motor magnet assembly  134  is also mounted to arms  125  opposite the head gimbal assemblies. Movement of the actuator  121  (indicated by arrow  135 ) by controller  119  moves the head gimbal assemblies radially across tracks on the disk  115  until the heads settle on their respective target tracks. 
         [0025]    While the invention has been shown or described in only some of its forms, it should be apparent to those skilled in the art that it is not so limited, but is susceptible to various changes without departing from the scope of the invention.