Abstract:
A lower cost metal layer free flexible conductive laminate segment is connected to a relatively smaller amount of the more expensive metal layer containing flexible conductive laminate segment to connect a slider to signal circuitry in a cost efficient way while avoiding biasing of the slider movement by the conductor.

Description:
REFERENCE TO RELATED APPLICATION 
     This application is a continuation in part of my copending application Ser. No. 08/897,660 filed Jul. 21, 1997, now U.S. Pat. No. 5,901,016 issued May 4, 1999. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention has to do with disk drive suspensions, and more particularly with improvements in the design and structure of disk drive suspension electrical connectors that are used to carry current between a load beam-supported slider and suspension-associated signal circuitry. In a specific aspect, the invention provides a disk drive suspension in which the advantages of flexible conductive laminate segments, including lower cost and easier fabrication, are maximally obtained while having the benefits of a metal layer containing flexible conductive laminate segment from the load beam rigid portion forward. 
     2. Related Art 
     Signal circuitry has been electrically connected to the slider, including the recording head carried by the slider, by various conductors including wire bundles and flexible circuitry with varying effectiveness and cost efficiencies. 
     SUMMARY OF THE INVENTION 
     It is accordingly an object of the invention to provide a disk drive suspension having electrical connections which provide substantially the benefits of a flexible circuit connection at lower cost and with easier fabrication, and while eliminating a junction at the proximate end of the suspension. It is another object to provide an improved suspension in which the manufacturing advantages of flexible circuit, including ready automation of slider-to-flexure assembly and substantially bias-free attachment to the slider are also realized. It is a further object to provide a suspension having a novel hybrid connector of metal layer free flexible circuit conductor and a wire layer including flexible circuit conductor, maximizing the advantages of each and minimizing the disadvantages of each in the resultant disk drive suspension. 
     These and other objects of the invention to become apparent hereinafter are realized in a disk drive suspension comprising a load beam having a distal rigid portion, and supported by the load beam a flexure carrying a slider head, an electrical connector running substantially the length of the load beam to the slider, the connector comprising an electrically integrated hybrid of different segments including a first flexible conductive laminate segment free of a metal support layer that is connected to signal circuitry and a second flexible conductive laminate segment including a metal support layer connected to the slider, the segments being arranged sequentially and in such manner that the slider head is electrically coupled by the first flexible conductive laminate segment at the proximal end of the load beam, and by the second flexible conductor at the load beam distal rigid portion. 
     In this and like embodiments, typically, the first flexible conductive laminate segment comprises at least one pair of conductive leads laminated with plastic dielectric, the first flexible conductive laminate segment is free of junctions between the signal circuitry and the second flexible conductive laminate segment, the second flexible conductive laminate segment is electrically connected to the slider substantially in slider movement bias free relation, and the first flexible conductive laminate segment constitutes the entire length of the electrical connector up to the load beam distal rigid portion. 
     In a further embodiment, the invention provides a disk drive suspension comprising a load beam having a distal rigid portion, and supported by the load beam a flexure carrying a slider head, an electrical connector carried by the load beam along a major portion of the connector length, the connector comprising a two-component structure of separate, physically different conductors including a first flexible conductive laminate segment consisting of copper conductors and plastic dielectric and a second flexible conductive laminate segment comprising copper conductors, plastic dielectric, and a stainless steel support laminated to the plastic dielectric, the conductors being joined at the proximate end of the load beam distal rigid portion to define an continuous electrical path for carrying current from the slider head to signal circuitry beyond the load beam. 
     In this and like embodiments, typically, the first flexible conductive laminate segment is free of junctions between the device electronics and the second flexible conductive laminate segment, the second flexible conductive laminate segment is electrically connected to the slider substantially in slider movement bias free relation, the first flexible conductive laminate segment constitutes the entire length of the electrical connector up to the load beam distal rigid portion, and the load beam is apertured rearwardly of the second flexible conductive laminate segment, the slider is located on a first surface of the load beam, and the first flexible conductive laminate segment is located on the opposite surface of the load beam, the second flexible conductive laminate segment being connected to the first flexible conductive laminate segment through the load beam aperture. 
     In a further embodiment, the invention provides in combination on a load beam: the noted first and second flexible conductive laminate segments, electrically coupled into a single electrical connector and arranged to conduct current from a slider to signal circuitry. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention will be further described in conjunction with the attached drawings in which: 
     FIG. 1 is a side elevation view, partly schematic, of a head stack assembly of load beams juxtaposed with the flexible conductive laminate segments. 
     FIG. 2 is an oblique view of the invention suspension; 
     FIG. 3 is a view taken on line  3  in FIG. 1; and, 
     FIG. 4 is a view taken on line  4  in FIG.  1 . 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The present invention suspension utilizes a novel electrical connector in which the major portion of the conductor is a metal layer free flexible conductive laminate and the minor portion is a second flexible conductive laminate conductor segment that includes a metal layer useful for acting as a flexure. The advantages of the invention include a reduction is cost since the flexible circuit without a metal layer is relatively inexpensive in comparison with the metal layer including laminate, used here in small quantities, just along the rigid portion of the load beam, and an absence of conductor bias at the slider/air bearing 
     The invention hybrid electrical connector uses a flexible circuit based flexure with circuit traces on a dielectric plastic and a metal layer support, that is connected to a metal layer free flexible circuit combination of traces and dielectric plastic immediately at the proximate end of the load beam rigid portion. This assembly offers the advantages that the costly metal layer containing flexible circuit can be used less than if it extended all the way to the actuator connection points, a important consideration given the high material cost of the metal layer flexible circuit conductor. Further the proximate first segment is readily handled; the distal second segment of the flexible circuit and flexure when formed as a strip also can be handled with known manufacturing procedures, including placement and welding, and automation is feasible. The product offers substantially the electrical performance of a wire bundle system. Moreover, manufacturing errors and other fabrication costs are typically reduced by having but one junction between the signal electronics at the base of the load beam at the actuator and the junction at the load beam rigid portion where the second segment commences. 
     With reference now to the drawing in detail, in FIGS.  1 - 4  the invention disk drive suspension  10  comprises a load beam  12  and a flexure  14  shown as a unit  16 . load beam  12  is generally planar and locally flanged to have side rails  18  in its rigid distal portion  20 . Load beam base portion  22  attaches to a mounting plate  24  which in turn mounts the load beam  12  to an actuator  25 . Signal circuitry element  26  is located at the proximate end  28  of the load beam  12  for the purpose of sensing and transmitting signal exchanges through electrical connector  66  with the slider  32  carried on flexure  14  attached to the load beam distal end  36 . Slider  32  defines an air bearing relative to the disk drive disk  34  and carries the electrical and magnetic portions of the head. 
     The load beam  12 , flexure  14 , slider  32  and signal circuitry element  26  shown are typical of suitable structures for their respective fluctions, with no particular form or design of load beam, flexure, slider or signal circuitry being critical to this invention. 
     The invention is concerned particularly with improvements in the design and form of the electrical connector  66  between the signal circuitry  26  and the slider  32 . The freedom of movement of the flexure  14 , and rotation of the slider  32  in various axes, is critical to the optimum functioning of the suspension  10 . It is nonetheless required to attach electrical connectors to the flexure and fine leads to the slider, without unduly affecting the movement freedom of these elements. In the present device, a first segment of the connector  66  comprising a metal layer-free flexible conductive laminate  41  is connected to a second connector segment comprising second flexible conductive laminate  42 . Second flexible conductive laminate  42  comprises metal support layer  43 , pairs of conductive leads  44 ,  46 , and plastic dielectric film  48 ; it can function as the flexure  32  and its leads used to electrically couple to the slider  32 . The flexible conductive laminate  42  segment is arranged to add no particular bias to flexure  32  movement. The use of flexible conductive laminate  42  as or with the flexure  14  enables automated attachment of the leads  44 ,  46  to the slider  32  as noted previously and is advantageous in the manufacturing process. 
     In cases where the connector  66  segment comprised of metal layer-free conductive laminate  41  does not lie on the same side of the load beam as the slider  32 , the load beam is apertured at  54  just beyond the proximal end of the load beam rigid portion  20 . The leads  44 ,  46  from the flexible conductive laminate  42  are gathered at the rigid portion proximal end  56  and there are accessible through aperture  54  of the load beam  12  for connection to the distal ends of leads  47 ,  49  of first flexible conductive laminate  41 . The first flexible conductive laminate  41  extends along the load beam  12  length to and through the aperture  54  for connection to the conductive leads  44 ,  46  of the flexible conductive laminate  42  to form electrical connector  66  running the length of the load beam and electrically interconnecting slider  32  and signal circuitry element  26 . The use of a major portion segment, typically at least two-thirds of the connector  66 , of the metal layer-less flexible conductive laminate substantially reduces cost as the laminate  41 , typically making up only one-third of the connector is considerably less expensive than the metal layer supported laminate  42 . In addition, the use of the flexible conductive laminate  41  in accordance with the invention makes the use of junctions other than at the signal circuitry  26  and the junction with flexible conductive laminate  42 . 
     The foregoing objects of the invention are thus met.