Abstract:
The present invention provides methods for laser sealing of disk drive housings. In addition, laser sealed housings are provided. Laser sealing of hard drives, allows for the disk drive assembly to be maintained in an inert gas environment.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to U.S. Provisional Application Ser. No. 60/385,522, filed Jun. 3, 2002; entitled, “Laser-based Metal Sealing Of Disk Drives”. The foregoing patent application, which is assigned to the assignee of the present application, is incorporated herein by reference in its entirety. 
    
    
     BACKGROUND OF THE INVENTION 
     In the highly competitive disk drive industry, manufacturers continually strive for improved performance along several fronts. Perhaps best known are the ongoing efforts to increase data storage capacity within given size limits by increasing the density at which bit-encoded data may be stored. Closely related, are the attempts to arrange the disk drive components to more effectively utilize available space, either to reduce the size of the drive, or to provide a drive of the same size with increased storage area, improved operating efficiency, or both. Moreover, there is effort to continuously improve drive performance and life. 
     Typically a disk drive will include a rigid and stationary housing, at least one storage disk, and a means for supporting the data storage disk inside the housing for rotation about a spindle axis relative to the housing. A drive typically further includes a transducing head for writing bit-encoded data onto the recording surface of the disk, and for reading bit-encoded data previously stored on the recording surface. An actuator means is provided inside the housing for controllably positioning the transducing head relative to the recording surface. Controlling electrical circuitry controls the rotation of the disk, the positioning of the transducing head and the writing and reading of the bit-encoded data. The control circuitry includes a circuitry layer, several electrical circuit panels, and means for bonding the electrical circuit plant panels to the circuitry layer to position the circuit panels apart from one another. A mounting means secures the circuit panels integrally with respect to the housing. The housing preferably is a rigid structure constructed of material capable of protecting the drive over its lifetime. 
     It has been observed that replacing the gas contents or interior environment of a disk drive with an inert gas, such as, for example but not limited to helium, improves drive performance by decreasing the power necessary to operate the drive. In addition, replacing the interior environment of the disk drive with an inert gas decreases turbulence and vibration. However, current methods of disk drive housing manufacture do not provide for a gas-tight or impermeable housing. Thus, in the ever-continuing requirement for improved disk drives, it is of interest in the art to develop improved disk drives, gas-tight disk drive housings, and methods of manufacture therefor. 
     SUMMARY OF THE INVENTION 
     The present invention provides a method for a laser-based sealing of disk drives, and for gas-tight disk drives. Preferably, the disk drive housing is made of aluminum or steel, and is constructed such that the disk drive components can be inserted therein, and then the disk drive housing can be sealed using a laser. Gas can be pumped into the disk drive housing after assembly by way of a valve or port; alternatively, assembly of the disk drive can take place in a gas environment, such as a helium environment. 
     Thus, the present invention provides a method of sealing a disk drive housing comprising providing a base component of the disk drive housing; providing a cover component of the disk drive housing; and laser-welding the base component to the cover component to seal the disk drive housing. In addition the method of the present invention may further include providing a spindle assembly inside the disk drive housing wherein the spindle assembly includes a data storage disk and an axially-extending spindle shaft for supporting the data storage disk; providing a data transducing head inside the disk drive housing proximate to the data storage disk; providing an electrical circuit means for controlling the rotation of the data storage disk; and providing an actuator means inside the disk drive housing for positioning the transducing head relative to the data storage disk. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The teaching of the present invention can readily be understood by considering the following detailed description in conjunction with the accompanying drawings. 
         FIG. 1  is perspective partial view of a disk drive with the top cover of the drive housing removed to illustrate certain features; 
         FIG. 2  illustrates on embodiment of a laser-based sealing apparatus for sealing a disk drive. 
         FIG. 3  is an exploded perspective view of a disk drive storage system. 
         FIG. 4  is a simple schematic of one embodiment of the method of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Turning now to the drawings, there is shown in  FIG. 1  part of a magnetic disk drive  16 . The disk drive has a rigid outer housing including a base  18  and a cover  20 . Cover  20  is removed from the base to reveal a disk pack or spindle assembly  22  and a rotary actuator  24 , both of which are mounted moveably with respect to the housing. More particularly, the spindle assembly  22  includes a top disk  26  and several additional concentrically stacked and spaced-apart disks rotatable about a vertical spindle axis  28 . 
     Rotary actuator  24  includes an actuator shaft  30  mounted to pivot relative to the base about a vertical actuator axis  32 . Several transducer support arms, including a top support arm  34 , are fixed to rotate with the rotator shaft. Each arm carries a magnetic data transducing head, for example, a transducing head  36  on a support arm  34 . The rotary actuator pivots to move the transducing head along arcuate paths generally radially of the disks. Selective actuator pivoting, in combination with controlled rotation of the disks, allows reading and recording of data at any desired location at any one of the disk recording surfaces. Actuator  24  is pivoted by selective application of electrical current to a voice coil  38  supported for arcuate movement within a magnetic field created by a permanent magnet arrangement  40  including several magnets and a poll piece (not illustrated in further detail). 
     The rotary actuator and spindle assembly are supported between two opposed housing walls, including a top wall  42  of a cover  20 , and a bottom wall of a base  18 . The spindle shaft and actuator shaft may be stationary, meaning that they are integral with the housing, with the disks and support arms being mounted to rotate relative to their respective shafts. 
     Cover  20  includes a vertical continuous sidewall structure including a rearward wall  86 , sidewall  88 , and a forward wall  90 . Here, the upper sidewall structure includes a flat, horizontal continuous bottom edge  92 , though some embodiments may include a flange or other mated fitting so as to fit into a top edge  100  of base  18  to facilitate a tight fit and/or laser-welding. Base housing  18  includes an upright wall structure including a forward wall  94 , a rearward wall  96 , and two opposed sidewalls, one of which is shown at  98 . These walls combine to form a continuous, horizontal top edge  100 . The present embodiment also shows an elastomeric seal  102  mounted to top edge  100  though seal  102  is optional. When cover  20  is assembled onto base  18 , confronting bottom edge  92  of cover  20  and top edge  100  of base  18  are brought into sealing engagement to close the housing about the spindle assembly and rotary actuator. 
     The upper and lower sidewalls are relatively thick to lend rigidity to the housing. Top wall  42  may be formed with a horizontal full height region  104 , a horizontal recessed region  106 , and interconnected by several non-horizontal regions as indicated at  108 ,  110  and  112 . The full height region accommodates the rotary actuator and spindle assembly. The non-horizontal regions provide additional stiffness to a top wall  42 , which strengthens the wall and enables a reduced thickness wall construction. 
       FIG. 2  shows a simplified laser sealing device  200 . The device has a control system  202 , a laser  206 , and communication  204  between control system  202  and laser  206 . Laser  206  is connected to laser focus head  210  by a fiber or direct coupling  208  and a means  214  to supply a laser beam  212  from laser  206  to laser focus head  210 . Laser  206  may be any type of laser suitable for the purpose of sealing a disk drive housing, including but not limited to an Ng:YAG (neodymium doped yttrium/aluminum/garnet crystal) laser. Laser beam  212 , is focused on drive housing  220  in order to laser seal the top of drive housing  220  to the bottom of drive housing  220 .  FIG. 2  shows the cover components meeting and being welded at a midpoint in the sidewall of the housing; however, the housing could be a flat base with a cover with sidewalls, in which case the weld would be positioned at the lower edge of the sidewall. Alternatively, the housing could be a flat cover with a base with sidewalls, in which case the weld would be positioned at the upper edge of the sidewall. Other configurations known in the art may be used as well. In addition, a flux or filler material supply  216  provides flux via flux line  228  for the laser-welding of drive housing  220 . Additionally, there is an inert gas supply  218  which supplies gas to fill drive housing  220 . 
     Alternatively, certain components of laser sealing device  200  (such as, for example, laser focus head  210 , flux line  228 , drive housing  220  and gripper  222 ) may be operated in a gas environment, such as an inert gas environment, making inert gas supply  218  unnecessary. Drive housing  220  is held in place and manipulated by way of a gripper  222  that attaches the drive housing  220  to a robotic manipulator  224 . The robotic manipulator  224  and gripper  222  assembly move the drive housing  220  such that the laser beam  212  laser welds the drive housing  220 . In addition, there is communication  226  provided between control system  202  and robotic manipulator  224 . 
       FIG. 3  is an exploded perspective view of a magnetic disk drive storage system. In this particular embodiment, storage system  310  includes a housing base  312  having a spindle assembly  314  which rotatably carries storage disks  316 . An armature assembly  318  moves transducers  320  across the surface of the disks  316 . The environment of disks  316  is sealed by seal  322  (optional), base  312 , and cover  324 . In this embodiment, base  312  does not have an upwardly-disposed sidewall structure as shown in  FIG. 1 . Instead, base  312  is essentially flat, and the sidewall structures  328  of cover  324  (two of which are shown) provide the sidewall structure for the housing. 
     According to the present invention, once housing base  312  is sealed by seal  322  to cover  324 , base  312  will be laser-welded to cover  324  using a laser sealing device like the one shown in  FIG. 2 , for example. Also, shown in this embodiment is a means  326  for communicating with the interior of storage system  310  once housing base  312  has been laser-welded to housing cover  324 . Means  326  can be a valve or a port which allows storage system  310  to be filled with gas once housing base  312  has been welded to housing cover  324  but is gas impermeable once the filing is complete. Such a valve or port may be any known in the art that permits gas to be injected into an enclosure but prevents gas from escaping thereafter, including, for example, a Schraeder-type valve. 
       FIG. 4  shows a simple schematic of one embodiment of a method  400  of the present invention. In a first step, a base component is provided  410 . Next, a disk drive assembly is coupled to the base component  420 . The disk drive assembly may include a spindle assembly, including at least one data storage disk and a spindle shaft for supporting the data storage disk, a data transducing head positioned proximate to the disk for writing bit-encoded data onto a recording surface of the disk, an electrical circuit means for controlling the rotation of the disk, and an actuator for positioning the transducing head relative to the disk. Next, in step  430 , a cover component of the housing is provided over the base component and the disk drive assembly. 
     Finally, in step  440 , the base component is laser-welded to the cover component. Both the base component and the cover component are manufactured such that, once laser-welded together, they provide an airtight disk drive housing. Either or both of the base component or cover component may contain a valve or port which allows for communication between the outside of the disk drive housing and the inside of the disk drive housing once laser-welding has taken place. This valve or port allows for the injection of gas into the housing once the housing has been sealed. Alternatively, the disk drive assembly can be assembled in an inert gas environment. The pressure of the inert gas in the housing is at or about atmospheric pressure or somewhat higher. 
     Various modifications to the methodologies and housing assemblies disclosed herein may occur to those skilled in the art without departing from the spirit and scope of the invention as defined by the appended claims.