Abstract:
Various configurations of cartridges for optical disks, particularly first-surface optical disks, are provided. The cartridges include a plurality of protectors for use in safeguarding the optical disk when certain conditions are present or certain events occur. The protectors include an elongated shutter that covers the hub assembly, at least annular slot portions inside of the cartridge to restrain movement of the disk within the cartridge, a locking subassembly to hold the shutter in a desired position, and a mechanism for preventing complete insertion of the cartridge into an optical drive when the cartridge is in the wrong orientation relative to the drive.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present application is related to U.S. patent application Ser. No. 09/315,398, filed May 20, 1999, entitled “Removable Optical Storage Device and System,” U.S. Provisional Application No. 60/140,633, filed Jun. 23, 1999, entitled “Combination Mastered and Writeable Medium and Use in Electronic Book Internet Appliance,” U.S. patent application Ser. No. 09/393,899, filed Sep. 10, 1999, entitled “Content Distribution Method and Apparatus,” U.S. patent application Ser. No. 09/393,150, filed Sep. 10, 1999, entitled “Writeable Medium Access Control Using a Medium Writeable Area,” U.S. patent application Ser. No. 09/457,104 filed Dec. 7, 1999, entitled “Low Profile Optical Head,” U.S. Patent Application Ser. No. 09/560,781 entitled “Miniture Optical Disk for Data Storage, ” and U.S. Patent Application Ser. No. 09/815,377 entitled “Tilt Focus Method and Mechanism for an optical Drive,” all of which are incorporated herein by reference in their entireties. 
    
    
     FIELD OF THE INVENTION 
     The present invention is directed generally to a low profile cartridge and specifically to a low profile cartridge for an optical disk. 
     BACKGROUND OF THE INVENTION 
     A number of disk-shaped optical storage media have been developed for use in storing various types of digital data in a manner such that the media can be readily removed from the read/write or drive device for which it is designed. A common type of optical media is second-surface optical media. In accordance with one definition, second-surface optical media can be defined in terms of the read operation that is conducted when reading information from the media. In particular, a second-surface optical medium can refer to a medium in which the read beam is incident on the substrate of the optical medium or disk before it is incident on the information content portions thereof. 
     The relatively thick and transparent substrate of second-surface optical media makes read-only or read-write operations relatively insensitive to dust particles, scratches and the like which are located more than 50 wavelengths from the information content portions thereof. On the other hand, the second-surface optical medium can be relatively sensitive to various optical aberrations. These optical aberrations include: (1) tilt of the substrate relative to the optical axis; (2) substrate thickness variations; and/or (3) substrate birefringence. 
     Another drawback associated with second-surface optical media is that the optical requirements of such media are substantially inconsistent with the miniaturization of the disk drive and optical components for such media. As will be appreciated, a longer working distance (distance between the objective lens and the information content portions) is required for an optical system that will read information from or write information onto second-surface media. This is due to the relatively thick transparent layer through which the radiation must pass to access the information content portions. To provide the longer working distance, larger optical components (e.g., objective lens) are required. 
     Because of these disadvantages associated with second-surface optical media, a first-surface optical medium has been devised by the assignee of the present application. Although it may be subject to more than one definition, in one embodiment, the first-surface optical medium refers to a medium in which the read beam during a read operation is incident on or impinges on information content portions of the first-surface optical medium before it impinges on a substrate of the first-surface optical medium. 
     The first-surface medium offers numerous advantages over a second-surface medium. By way of example, with the first-surface medium, the radiation does not pass through the relatively thick substrate so that there is a relatively shorter optical path, in comparison with second-surface medium, thereby providing a significantly shorter working distance, in comparison with second-surface medium. Since there is a shorter working distance, a smaller objective lens diameter, for a given numerical aperture, can be utilized which results in smaller, lower mass optical components to achieve a greater degree of optical drive miniaturization. Furthermore, the first-surface medium is not sensitive to substrate birefringence and substrate thickness variations. The first-surface medium is also much less sensitive to substrate tilt. 
     However, because there is no protective layer with a first-surface optical medium, to protect it from damage or being subject to unwanted particles or debris, it is imperative that a sufficiently protective housing or cartridge be employed to contain the optical medium. There are a number of factors to be considered in designing the protective cartridge for first-surface optical media. The cartridge should include a number of complementary and/or redundant protective features. For example, the cartridge should have features to protect the enclosed first-surface disk from damage such as by scratches and abrasions caused by handling of the cartridge or rotation of the enclosed disk during read and/or write operations. As will be appreciated, the cartridge should be designed to prevent contact of a surface of the cartridge with the operational surface of the disk. The cartridge should have features to retard the entry of dust and other foreign matter into the interior of the cartridge. Such foreign matter can prevent the optical head from reading information from or writing information to the disk. The cartridge should have a small form factor to permit the cartridge to be used with small, hand-held electronic devices, such as PEDs (Personal Electronic Devices) and digital cameras. The cartridge should have features to self-locate the cartridge in the disk drive. Such features facilitate proper alignment of the operational surface and data tracks relative to the optical head. The cartridge should also have features permitting the use of a double-sided, first-surface, optical disk. In other words, the cartridge should permit the optical head to access both of the opposing operational surfaces of the disk. 
     SUMMARY OF THE INVENTION 
     These and other design considerations are satisfied by one or more of the cartridge embodiments of the present invention. 
     In a first embodiment of the present invention, an apparatus for use in an optical system is provided. The apparatus includes a cartridge assembly having upper and lower shutter members that move independently of one another. In particularly preferred configuration, a single mechanism, such as a rotary arm mounted in the disk drive, engages and moves each of the shutter members. In one configuration, the mechanism engages and moves a first (but not a second) shutter member when the cartridge assembly is inserted into the disk drive in a first orientation and engages and moves the second (but not the first) shutter member when the cartridge assembly is inserted into the disk drive in a second orientation that is different from the first orientation. In one application, the first orientation is the flip side (or reverse) of the second orientation. 
     In another embodiment, a cartridge assembly is provided that includes a double-sided optical medium, access openings (for the optical head) located on opposing surfaces of the cartridge assembly, and one or more shutter members that are movably disposed to cover or uncover (simultaneously or sequentially) the access openings. In this manner, the cartridge assembly can be inserted into the disk drive in a first orientation to reveal a first operational surface of the medium and in a second orientation to reveal a second operational surface of the medium. As noted above, the first orientation can be the flip side (or reverse) of the second orientation. 
     In yet another embodiment, an apparatus for use in an optical system is provided. 
     The apparatus includes: 
     (a) an optical storage medium (which can be first- or second-surface) having at least a first side for storing information; 
     (b) a hub assembly operatively associated with the optical storage medium; and 
     (c) a cartridge assembly that contains the optical storage medium and the hub assembly. The cartridge assembly includes a first optical storage medium protector for use in safeguarding the optical storage medium against the occurrence of one or more unwanted events and a second optical storage medium protector for use in safeguarding the optical storage medium against the occurrence of one or more second unwanted events. The unwanted events, for example, can be contact of the operational surface of the disk with a cartridge wall(s) due to inward deflection of the cartridge wall(s) by a user, contact of the operational surface of the disk with the cartridge wall(s) during rotation of the disk by a disk drive, and collection of foreign matter on the disk operational surface. 
     The first and second optical storage medium protectors are preferably selected from a variety of features. 
     In one configuration, the first and/or second optical storage medium protectors include a first major wall (e.g., a shutter wall) covering a hub member of the hub assembly. Not only does the cartridge wall block foreign matter from entering into the interior of the cartridge through a hole in the cartridge wall(s) to permit the disk drive to engage the hub member, but also the hub member provides structural support to the wall to resist deflection. In one configuration, an inner surface of the first major wall is spaced from the adjacent outer surface of the hub member such that, when a force is applied to the wall, the interior surface contacts the outer surface of the hub member to thereby constrain inward wall deflection, but does not contact the operational surface of the optical storage medium. 
     In another configuration, the first and/or second optical storage medium protectors include a locking subassembly having first and second positions. When the locking subassembly is in the first position, access to the hub member and/or optical storage medium is blocked (e.g., by a movable shutter wall member) and when the locking subassembly is in the second position access to the hub member and/or optical storage medium is available. In one design, a laterally movable wall or shutter is disposed so as to cover an access door in the cartridge wall for the optical head, as well as an opening in the cartridge wall for the hub member, in the first position and uncover the access door for the optical head, and the opening for the hub member, in the second position. 
     In yet another configuration, the cartridge assembly further includes a third optical storage medium protector. The third optical storage medium protector includes a medium constraining member having portions that overlie a peripheral edge of the optical storage medium. The third optical storage medium protector can be a annular slot positioned around the periphery of the medium for receiving a peripheral edge of the medium in between opposing surfaces of the slot. The opposing surfaces of the slot are interiorly offset from a surface of a wall of the cartridge to suspend the medium above, and avoid contact of the medium with the interior surface. 
     In yet another embodiment, an apparatus for use in an optical system is provided. The apparatus includes: 
     (a) a hub assembly having a total height and including at least a first hub member, with the total height including at least a height of the first hub member; 
     (b) an optical storage medium having a thickness and including a first side and a second side, with at least the first side storing information; and 
     (c) a cartridge assembly for containing the hub assembly and the optical storage medium. The cartridge assembly has a low profile. The ratio of the cartridge assembly height to the total height of the hub assembly is typically less than about 1.50 and more typically ranges from greater than 1.00 to about 1.25. 
     In yet a further embodiment, an apparatus for use in an optical system is provided. The apparatus includes: 
     (a) an optical storage medium; and 
     (b) a cartridge assembly including a holding feature (e.g., at least one of a locating pin and a locating hole) and a displacement feature (e.g., at least one of an anti-rotational pin and an anti-rotational slot). In one configuration, one of the locating pin and hole and one of the anti-rotational pin and slot are each located on the disk drive with the other being located on the cartridge housing. The anti-rotational slot has a larger cross-sectional extent or area than the locating hole to permit the disk drive to displace the cartridge housing along an arc extending along the anti-rotational slot (e.g., rotate the housing), the center of which is located at the center of the locating pin. In this manner, the disk drive is able to displace the cartridge housing as needed to correctly align the cartridge in a plane parallel to an operational surface of the medium. In another configuration, the disk drive includes one or more datum features (e.g., one or more contact surfaces) for contacting one or more surfaces of the cartridge assembly to correctly position the cartridge in a plane normal to the operational surface of the medium. These features facilitate alignment of the medium in the plane for substantially optimal focus and servo control. 
     In yet a further embodiment, a method is provided for safeguarding an optical storage medium. The method includes the steps of: 
     (a) providing a cartridge assembly including a housing having a major wall with an inner wall surface and containing (i) an optical storage medium side and (ii) a hub assembly joined to the optical storage medium, with one or more portions of the major wall covering a first hub member of the hub assembly; and 
     (b) opening a locking subassembly when access to the optical storage medium is being provided. 
     In yet another embodiment, an apparatus for use in an optical system is provided that includes: 
     (a) an optical storage medium having at least one operational surface for storing information; and 
     (b) a cartridge assembly that contains the optical storage medium and includes a lockout subassembly. The cartridge assembly is properly insertable into a disk drive in a first orientation and improperly insertable into the disk drive in a second orientation. The lockout subassembly permits the cartridge assembly to be inserted fully into the disk drive in the first orientation and retards the cartridge assembly from being inserted fully into the disk drive in the second orientation. 
     In one configuration, the lockout subassembly includes a slot for engaging a rotary arm located in the disk drive, thereby inhibiting full insertion of the cartridge assembly in the second orientation. The cartridge assembly can include a second lockout subassembly located on an opposing side of the cartridge assembly from the first lockout subassembly to safeguard the cartridge from being improperly inserted when the cartridge assembly is flipped over. 
     As will be appreciated, the foregoing summary of the invention is neither exhaustive nor complete. Other embodiments including one or more of the features referred to above and/or one or more of the features discussed below are envisioned by the present disclosure. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a top plan view of a cartridge assembly according to a first embodiment of the present invention; 
     FIG. 2 is a disassembled view of the cartridge assembly of FIG. 1; 
     FIG. 3 is a rear end view of the assembled cartridge assembly of FIG. 1; 
     FIG. 4 is a front end view of the assembled cartridge assembly of FIG. 1 with both shutter members in the closed and locked position; 
     FIG. 5 is side view of the assembled cartridge assembly of FIG. 1; 
     FIG. 6 is another disassembled view of cartridge assembly of FIG. 1; 
     FIG. 7 is another disassembled view of cartridge assembly of FIG. 1; 
     FIG. 8 is a sectional view taken along line  8 — 8  of FIG. 5 when the shutter member is in the closed position (the disk being removed for purposes of illustration); 
     FIG. 9 is a sectional view taken along line  8 — 8  of FIG. 5 when the shutter member is in the partially open (unlocked) position (the disk being removed for purposes of illustration); 
     FIG. 10 is a sectional view taken along line  8 — 8  of FIG. 5 when the shutter member is in the fully open (unlocked) position (the disk being removed for purposes of illustration); 
     FIG. 11 is a disassembled view of a drawer assembly for receiving the cartridge assembly (with the top of the page facing away from the disk drive spindle); 
     FIG. 12 is a plan view of the drawer assembly of FIG. 11; 
     FIG. 13 is a plan view of the cartridge assembly being inserted into the drawer assembly; 
     FIG. 14 is a another plan view of the cartridge assembly being inserted into the drawer assembly; 
     FIG. 15 is a another plan view of the cartridge assembly being inserted into the drawer assembly; 
     FIGS. 16A and B are more plan views of the cartridge assembly being inserted into the drawer assembly, with FIG. 16B having the cover removed to better illustrate the rotary arm and locking plate; 
     FIG. 17 is a top sectional view taken along line  8 — 8  of FIG. 5 when the cartridge assembly is being inserted properly into a disk drive according to another embodiment of the present invention; 
     FIG. 18 is another top sectional view taken along line  8 — 8  of FIG. 5 when the cartridge assembly is being inserted properly into the disk drive of FIG. 17; 
     FIG. 19 is yet another top sectional view taken along line  8 — 8  of FIG. 5 when the cartridge assembly is being inserted properly into the disk drive of FIG. 17; 
     FIG. 20 is a further top sectional view taken along line  8 — 8  of FIG. 5 when the cartridge assembly is being inserted properly into the disk drive of FIG. 17; 
     FIG. 21 is a further top sectional view taken along line  8 — 8  of FIG. 5 when the cartridge assembly is fully inserted and seated in the disk drive of FIG. 17; 
     FIG. 22 is a bottom plan view of the cartridge assembly when the shutter member is in the fully open position; 
     FIG. 23 is an end view of the cartridge assembly when a (lower) shutter member is in the open position; 
     FIG. 24 is a top sectional view taken along line  8 — 8  of FIG. 5 when the cartridge assembly is being inserted improperly into a disk drive; 
     FIG. 25 is a cross-sectional view along line  25 — 25  of FIG. 1; 
     FIG. 26 is a top view of the cartridge assembly of FIG. 1 in a disk drive assembly; 
     FIG. 27 is a cross-sectional view taken along lines  27 — 27  of FIG. 26 (with the cartridge assembly in position on the disk drive spindle); 
     FIG. 28 is a cross-sectional view taken along line  28 — 28  of FIG. 26 (with the cartridge assembly in position on the disk drive spindle); 
     FIG. 29 is a cross-sectional view taken along line  29 — 29  of FIG. 26 (immediately before the cartridge assembly is lowered into position on the disk drive spindle); 
     FIG. 30 is a disassembled view of a cartridge assembly according to another embodiment of the present invention; 
     FIG. 31 is a disassembled view of a cartridge assembly according to another embodiment of the present invention; 
     FIG. 32 is a top view of the cartridge assembly of FIG. 31 with the shutter in the closed and locked position; 
     FIG. 33 is a partial disassembled view of first housing member and shutter member of the cartridge assembly of FIG. 31; 
     FIG. 34 is a disassembled view of a cartridge assembly according to a yet another embodiment of the invention; 
     FIG. 35 is a disassembled view of cartridge assembly according to another embodiment of the present invention; 
     FIG. 36 is a top view of the cartridge assembly of FIG. 35 with the shutter in the closed and unlocked position; 
     FIG. 37 is a disassembled view of a cartridge assembly according to yet another embodiment of the present invention prior to insertion in the cartridge assembly; 
     FIG. 38 is a top view of the cartridge assembly of FIG. 37 with the shutter member being depicted in different positions; 
     FIG. 39 is an isometric view of selected components of the cartridge assembly of FIG. 37; 
     FIG. 40 is a cross-sectional view taken along line  40 — 40  of FIG. 37; and 
     FIG. 41 is a side view of the shutter member of FIG. 37 prior to insertion in the cartridge assembly. 
    
    
     DETAILED DESCRIPTION 
     Referring to FIGS. 1-6 and  22 - 23 , a removable, recordable or prerecorded optical, magnetic, or magneto-optical storage cartridge assembly  100  according to a first embodiment of the invention is depicted. The cartridge assembly includes first and second housing members  104   a  and  104   b  (FIGS. 2 and 6) (which are identical to one another), first and second shutter members  108   a  and  108   b  (FIGS. 2 and 6) (which are also identical to one another), locking arms  113   a,b  (which are also identical to one another) and an information-containing medium  116  (which is preferably an optical, first- surface medium). The first and second housing members define a substantially rectangular sidewall  107  (FIG. 1) having substantially planar top and bottom surfaces to enclose and protect the medium  116  (which is typically double-sided). 
     Referring to FIG. 1, the form factor of the cartridge assembly can be relatively small. In one configuration, the width “W” of the cartridge assembly is less than about 40 mm, and typically ranges from about 30 to about 37 mm, the length “L” is less than about 42 mm and typically ranges from about 30 to about 40 mm, and the height “H” (FIG. 3) is less than about 5 mm and typically ranges from about 1 to about 3 mm. In another configuration, the cartridge assembly has a mass less than about 7 gm, preferably less than about 5 gm. 
     In one configuration (FIGS.  2  and  4 ), the medium  116  is a double-sided rigid or semi-rigid film-type disk and is joined to a rigid or semi-rigid hub assembly  106  having first and second hub members  124   a,b . The medium  116  and hub assembly  106  are described in co-pending application Ser. No. 09/560,781 entitled “Miniature Optical Disk for Data Storage,” which is hereby incorporated by reference. 
     The first and second housing members  104   a,b  form the primary enclosure for the medium  116 . The housing members  104   a,b  each contain interlocking features  105   a-f  (e.g., pin-and-hole (shown in FIGS. 2 and 6) and tab-and-slot arrangements and the like) that make them self-locating with respect to one another during manufacture. Each of the housing members  104   a,b  includes a circular opening  120   a,b  for receiving the first or second hub member  124   a,b  attached to opposing sides of the medium  116  (for a double-sided disk) and a window  128   a,b  (FIGS. 2 and 6) to permit the optical head (not shown) to access the medium  116  during read and/or write operations. Although the window  128  is normally an empty space, the window can be covered by a (non-movable) transparent material (at least at the wavelength of the read/write beam) for additional protection of the medium. Examples of cover materials include glass and polycarbonate. 
     The first and second housing members  104   a,b  are preferably made by injection molding of a thermosplastic material, though other processes (such as stamping, machining, and the like) and other materials (such as aluminum, steel, or other metals, resins, fiberglass, ceramics and the like) can also be used. The polycarbonate can include a filler that is a lubricant such as “TEFLON” glass, or graphite to provide lubricity for moving parts and/or a filler than is an anti-static (or conductive) material such as metal powders. In one configuration, one or both housing members  104   a,b  are composed of a translucent (unclear or colored) or transparent (clear) material, such as a polycarbonate, to facilitate ultraviolet curing of an adhesive used to join the members. As will be appreciated, the adhesive is cured by illuminating the adhesive with ultraviolet light. 
     Each of the first and second housing members  104   a,b  has an offset, annular, disk-shaped, interior surface  132   a,b  (FIGS. 2 and 6) to hold the medium  116  therebetween. Referring to FIG. 25, the surface  132   a,b  is bounded by a radial or annular step  136   a,b  located interiorly of the peripheral edge  140  of the medium  116  (i.e., the radial distance from the step  136  to the hub center  144  (FIGS. 2 and 6) is less than the radial distance from the peripheral edge  140  of the medium to the hub center  144 ). Radially disposed walls  160   a,b  are combined when the housing members  104   a,b  are joined together. The wall  160  and opposing walls  166   a,b  define an annular slot for receiving and constraining movement of medium portions adjacent to the peripheral edge  140  of the medium  116 . 
     With this configuration, each of the operational surfaces  148   a,b  of the medium  116  is spaced a distance “S” (FIG. 25) from each of the interior surfaces  133   a,b  of the housing members  104   a,b . This prevents the interior surfaces  133   a,b  from contacting the adjacent operational surfaces  148   a,b . Such contact could occur in response to compression of the cartridge assembly walls  156   a,b  by a user, movement of the medium  116  in the cartridge assembly during handling by the user (medium  116  is loosely mounted within the cartridge assembly to permit alignment of the medium  116  independent of the position of the housing members  104   a,b ), insertion or ejection of the cartridge into or from the disk drive, and/or rotation of the medium  116  when the medium  116  is warped. In one configuration, the distance “S” ranges from about 0.3 to about 0.5 mm. In another configuration, the height “H 1 ” of the step  136   a,b  typically ranges from about 0.1 to about 0.2 mm, or from about 16% to about 33% of the thickness “T” of the medium  116 , and the distance “H 2 ” between opposing interior walls  166   a,b  of the annular slot ranges from about 0.5 to about 0.7 mm or from about 85% to about 115% of the thickness “T”. 
     The formed radially disposed wall  160  is located exteriorly of the peripheral edge  140  of the medium  116  (i.e., the radial distance from the wall  160  to the hub center  144  is more than the radial distance from the peripheral edge  140  of the medium  116  to the hub center  144 ) to enclose the medium  116  within the cartridge. The clearance “C o ” between the peripheral edge  140  of the medium  116  and the wall  160  should be as small as possible for the medium  116  to be centered in the disk drive and typically ranges from about 0.2 to about 0.4 mm. The overlap distance “D o ” from the step  136  to the medium peripheral edge  140  typically is less than the clearance C o . 
     To provide further constrainment of vertical movement of the medium  116  in the cartridge assembly and protection of the information-containing surface(s) of the medium from harmful contact with a housing member  104  surface, each of the housing members  104   a,b  includes a rim or radial step  152   a,b  (FIGS. 2 and 6) adjacent to and bounding the circular openings  120   a,b . The height “H 3 ” (FIG. 25) of the radial step  152  above the surface  133  typically ranges from about 0.1 to about 0.3 mm. A radial distance “D r ” (FIGS. 2 and 6) is defined between the radial steps  152  and  136  (relative to hub center  144 ). 
     Referring to FIGS. 1-2 and  6 , the first and second housing members  104   a,b  have indented surfaces  174   a,b  and  175   a,b  for labels. The depth of the indented surfaces relative to the surrounding raised outer wall portion  180   a,b  of the members  104   a,b  is typically from about 0.1 to about 0.3 mm. 
     The first and second housing members  104   a,b  are configured to end or side load (straight insertion) into a disk drive  177  (FIGS.  12 - 21 ). Compared to top loading, end or side loading provides a self-contained volume in which all drive functions are contained. To facilitate end or side loading, each housing member  104   a,b  has left and right lead-in radii  184   a,b  and lead-out chamfers  185   a,b  for cartridge ejection (FIGS. 3,  5 , and  6 ). In one configuration, the chamfer angle θ (FIG. 1) common to the lead-out chamfers  184   a-d  ranges from about 25° to about 75°. 
     Referring to FIGS. 1-23, the windows  128   a,b  in the first and second housing members  104   a,b  are covered by a respective “L”-shaped shutter member  108   a,b  when the cartridge assembly  100  is not inserted in the disk drive  177  (FIGS. 26-29) and uncovered by (lateral or alternatively rotational) movement of the respective shutter member when the cartridge assembly  100  is inserted in the disk drive  177  to permit the optical head  206  (FIG. 26) to access the medium  116  via the pertinent window  128   a,b . As discussed in detail below, during insertion of the cartridge assembly into the drive, the shutter member  108   a,b  for the pertinent window to be accessed by the optical head  206  is moved laterally as shown in FIGS. 11-16B by a rotary arm  700  and locking plate  704  in the disk drive. The other shutter member  108   a,b  remains stationary during the insertion process. This is shown in FIG. 4 which illustrates that the two shutter members  108   a,b  are vertically spaced apart from one another to permit independent movement. 
     The L-shape of the shutter member provides several benefits during the opening and closing of the shutter member. The elongated base portion of the “L” (which is located at the front of the cartridge assembly  100 ) provides stability and guidance during shutter member movement and thereby inhibits cocking and/or jamming of the shutter member. The narrow top portion of the “L” (which is located in the central and rear portions of the cartridge assembly  100 ) allows for more label area than a rectangular shutter member. The L-shaped shutter member does not contact the label area as in the case of a rectangular shutter member. 
     Each shutter member  108  includes inwardly facing tabs  214   a,b  and a tab  218 . Tabs  214   a,b  ride in slots  222   a,b , respectively, and tab  218  engages a corresponding slot  230  in the respective cartridge housing member  104   a,b . During manufacture, tab  218  is inserted into slot  230  and is bent downwardly as shown in FIGS.  3  and  6 - 7  to avoid contact of the tab  218  with (and damage to) information-containing portions or the operational surface of the medium  116 . The movement of the tabs in the slots permits lateral movement of the shutter members in response to the rotary arm in the disk drive assembly  177  rotatably engaging the slot  234   a,b  in the pertinent shutter member and applying a lateral force thereto to cause lateral (side-to-side) displacement of the shutter member. The design of a suitable insertion mechanism (e.g., rotary arm device) and ejection mechanism is described in Ser. No. 09/315,398 filed May 20, 1999 (which is incorporated herein by this reference). 
     To permit lateral displacement of each shutter member  108   a,b  without contact of the tab  218  with the medium  116 , each housing member  104   a,b  includes an indented surface  157   a,b  (FIGS. 2 and 6) to provide travel area for the shutter member and an indented surface  156   a,b  to provide travel area for the outwardly facing tab  218 . The indented surface  157   a,b  has a depth relative to the adjacent raised wall portions  180   a,b  typically ranging from about 0.05 to about 0.20 mm. The indented surface  156   a,b  has a depth relative to the adjacent surface  133   a,b  typically ranging from about 0.02 to about 0.10 mm. 
     To fixedly hold the shutter member when in the closed position and to return the shutter member to the closed position after removal of the cartridge assembly from the disk drive (i.e., disengagement of the rotary arm  269  from the slot  234 ), a locking subassembly is provided. The locking subassembly includes a locking arm  113   a,b.    
     Referring to FIGS. 6 and 8, the locking arm  113  includes a spring member  215  to resist displacement of the locking arm  113 , a locking nub  217  that engages the slot  234  in the shutter member  108 , and a stop arm  219  that restricts outward (counterclockwise rotational) and inward (clockwise rotational) movement of the locking arm  113 . The locking arm  113  is rotatably disposed in between the corresponding opposing surfaces  254   a,b  and  258   a,b  by means of a hole  259   a,b  in the locking arm  113  which engages a corresponding pin  261   a,b  connected to the housing member  104   a,b  (FIGS.  2  and  6 ). When the locking nub  217   a,b  engages the slot  234   a,b  (FIG.  9 ), the spring member  215   a,b  exerts little or no outward force against the bearing surface  263   a,b  of the housing member  104   a,b . The spring member  215   a,b , however, applies a resistive force against removal of the locking nub  217   a,b  from the slot  234   a,b  and lateral movement of the respective shutter member  108   a,b , with the magnitude of the resistive force being directly proportional to the degree of displacement (clockwise rotation) of the locking arm  113 . 
     The wall  236  and the displacement controlling member  114   a,b  of the housing member  104   a,b  control rotational displacement of the locking arm  113   a,b  to prevent overcompression and damage of the spring member  215 . This can occur, for example, when a user unlocks the shutter member by using an object to dislodge the locking nub inwardly. As will be appreciated, the degree of rotational movement of the locking arm in the clockwise direction is limited by the engagement of the rear of the stop arm  219  and the wall  236 . The degree of rotational movement of the locking arm in the counterclockwise direction is limited by the engagement of the front of the stop arm  219  and the member  114 . 
     FIG. 7 shows an alternative configuration of the cartridge assembly  100  that includes two spring members  112   a,b  to assist closure of the shutter members  108   a,b  (by resisting the opening of the respective shutter member engaging the spring member). Each spring member  112  has a plane of flexure substantially parallel to the inner walls or surfaces  254   a,b  and  258   a,b  of the housing members. The spring member  112   a  is provided between the opposing surfaces  254   a  and  258   a  of the housing members  104   a,b . The spring member  112   b  is provided between the opposing surfaces  254   b  and  258   b  of the housing members  104   a,b . Each spring member  112   a,b  is positioned in a spring guide slot  250   a,b  in an associated housing member  104   a,b  and is received in an indentation  115  in tab  214   a,b  to thereby bias the corresponding tab  214   a,b  of the shutter member  108   a,b . The ends  300   a,b  of the spring members  112   a,b  are transverse to the plane of flexure of the spring member to permit the ends to ride in spring guide slots  250   a,b  and bias the end of each tab  214   a,b  of each shutter member  108   a,b.    
     As shown in FIGS. 11-16B, a drawer assembly receives the cartridge and cooperates with the cartridge assembly to open the shutter member. The drawer assembly includes a rotary arm  700  movably (rotatably) engaging a locking plate  704  via a pin  708 ; a sleeve  117  for receiving the cartridge assembly, and a partial cover  716 . The sleeve  117  includes leaf springs  720   a,b  to facilitate insertion of the cartridge assembly in the sleeve  117  and centering of the disk on the disk drive and disks  712   a-c  which are received in guide tracks (not shown) in the disk drive for movement in direction  724  of the sleeve  117 . The sleeve  117 , pin  708 , cover  716 , and disks  712   a-c  are typically formed from metal such as stainless steel. The locking plate  704  is also typically formed from metal, with brass being preferred. The rotary arm  700  can be formed from metal or plastic. 
     Operation of the locking subassembly and the shutter member will be discussed with reference to FIGS. 8-16B. When the shutter member  108   a,b  is in the locked and closed position (FIG.  7 ), the locking nub  217   a,b  projects into the locking slot  234   a,b  and the spring member  215   a,b  is in an uncompressed (or slightly compressed) state. The cartridge assembly  100  is inserted into the disk drive  177  as shown in the sequence of FIGS. 12-16. As the cartridge assembly  100  moves into the disk drive  177 , an unlocking nub  730  rotatably positioned on a distal end  734  of the rotary arm  700  engages the locking nub  217   a,b  (FIG.  14 ). As the user continues to push the cartridge assembly  100  into the disk drive  177 , the unlocking nub  730  displaces the locking nub  217   b  inwardly (and rotates the locking arm  113   a,b ) until the locking nub  217   b  is disengaged from (and the unlocking nub  730  engages) the locking slot  234   a,b  and the shutter member  108   a,b  is in the unlocked and movable position (FIGS.  9  and  14 ). In response the spring member  215   a,b  exerts a resistive force (by being forced against bearing surface or wall  236   a,b ) against displacement of the locking arm  113   a,b  by the rotary arm  700 . The stepped front surfaces  738   a,b  of the unlocking nub  730  hooks the locking slot  234   a,b  and displaces the shutter member  108   a,b  laterally in direction  742  as shown in FIG.  15 . In response to the insertion force  746  against the cartridge assembly  100 , the rotary arm  700  rotates in a counterclockwise direction  750  and the locking plate rotates in a clockwise direction  754  (relative to the rotary arm) and displaces the shutter member to the fully open and unlocked position (FIGS. 10,  16 A and B, and  22 - 23 ). The rotary arm  700  causes the leading edge  263   a,b  of the shutter member  108   a,b  to engage the similarly shaped raised edge  264   a,b  of the housing member  104   b  (FIG.  16 ). In the open position, the rotary arm is substantially aligned with (or parallel to) the planar front face  277  of the cartridge assembly  100  and the front face of the shutter member  108   a,b  (FIG.  16 ). The locking arm  113   a,b  is returned to its original (starting) position by the bias of the spring member  215   a,b  (FIG.  10 ). 
     When the user ejects the cartridge assembly  100  from the disk drive  177  by a mechanical device (not shown), the cartridge assembly  100  is pushed out of the disk drive and/or drawer assembly, and the rotary arm  700  is laterally displaced in a clockwise direction until the shutter member  108  and locking arm  113   a,b  are returned to their original positions of FIG.  8 . As will be appreciated, the inclined or cammed surface  281   a,b  (FIG. 10) of the locking arm  113   a,b  facilitates movement of the shutter member  108  over the locking nub  217   a,b  during this process. As the cartridge assembly  100  is removed from the disk drive  177  and the rotary arm  700  disengaged from the slot  234   a,b , the locking plate forces the trailing edge  283   a,b  of the corresponding shutter member  108   a,b  to the closed position against the raised, inner step  262   a,b  of the housing member  104   a,b  (FIG.  1 ). As will be appreciated, the raised inner step  262  is shaped the same as the trailing edge  283   a,b  of the shutter member  108   a,b . The spring member  215   a,b  then forces the locking nub  217   a,b  to engage the locking slot  234   a,b  and return the shutter member  108   a,b  to the locked and closed position. As will be appreciated, the stepped edge  280   a,b  of the locking arm  113   a,b  engages the edge of the slot  234   a,b  to prevent the shutter member  108   a,b  from being displaced during storage and/or handling. 
     Another embodiment of a cartridge unlocking assembly is shown in FIGS. 17-21. An unlocking nub  265 , positioned on a distal end  267  of a rotary arm  269 , engages the locking nub  217   a,b  (FIG.  18 ). As the user pushes the cartridge assembly  100  into the disk drive  177 , the unlocking nub  267  displaces the locking nub  217   b  inwardly (and rotates the locking arm  113   a,b ) until the locking nub  217   b  is disengaged from the locking slot  234   a,b  and the shutter member  108   a,b  is in the unlocked and movable position (FIG.  19 ). In response the spring member  215   a,b  exerts a resistive force (by being forced against bearing surface  236   a,b ) against displacement of the locking arm  113   a,b  by the rotary arm  269 . The stepped front surface  271  of the unlocking nub  265  hooks the locking slot  234   a,b  and displaces the shutter member  108   a,b  laterally in direction  237  as shown in FIG.  20 . In response to the insertion force  275  against the cartridge assembly  100 , the rotary arm  269  rotates in a clockwise direction  277  against the force of the spring member  112   a,b  and displaces the shutter member to the fully open and unlocked position (FIG.  20 ). The rotary arm  269  causes the leading edge  263   a,b  of the shutter member  108   a,b  to engage the similarly shaped raised edge  264   a,b  of the housing member  104   b  (FIG.  21 ). In the open position, the rotary arm is substantially aligned with (or parallel to) the planar front face  277  of the cartridge assembly  100  and the front face of the shutter member  108   a,b  (FIG.  21 ). 
     The shutter member  108   a,b , when in the closed and locked position, protects the medium  116  from damage and seals the cartridge interior from foreign debris. Referring to FIG. 1, the shutter member  108   a,b  extends from a front (or loading) end  270  of the cartridge assembly  100  to a point on the other side of the hub assembly  106 . The flexible shutter member  108  contacts the hub member  124  while avoiding contact with the medium  116  when flexed inwardly, i.e. when the shutter member  108   a,b  is moved towards the hub member(s)  124   a,b . Additional structural support is provided to the shutter member by the end portions  274   a,b  and the peripheral side portions  278   a,b  of each shutter member  108   a,b . These overlap and engage the indented surface  157  of the housing member adjacent to the opening  120   a,b  and window  128   a,b  when the shutter member  108   a,b  is displaced inwardly. In this manner, the shutter member acts as a load bearing member that provides additional protection to the medium  116  by resisting compression of the cartridge wall (e.g. by a user). The positioning of the shutter member  108   a,b  over the hub member further closes the opening and windows and thereby inhibits the entry of foreign matter, such as dust, into the interior of the cartridge. 
     The shutter members and housing members  108   a,b  and  104   a,b  can be composed of the same or different materials. In one configuration, the shutter members are metal (e.g., stainless steel) and the housing members are plastic (e.g., polycarbonate). In this configuration, the shutter members thus have greater yield and tensile strengths than the housing members. 
     Referring to FIGS. 26-29, alignment of the cartridge assembly  100  in the disk drive  177  will now be described. As will be appreciated, to facilitate alignment of the medium  116  in the disk drive  177 , it is necessary to first properly spatially align the cartridge assembly  100  in the drive  177 . 
     Referring to FIGS. 26-29, cartridge assembly alignment is performed in the X and Y directions using anti-rotational slots  190   a,b  and locating holes  194   a,b  formed in each housing member  104   a,b . These engage an anti-rotational pin  198  and locating pin  202 , respectively. Specifically, anti-rotational slot  190   a  is aligned with the locating hole  194   b  and the locating hole  194   a  is aligned with the anti-rotational slot  190   b  to permit the cartridge to be flipped in the disk drive depending upon which operational surface  148   a,b  of the double-sided medium  116  is to be accessed. Depending on which side of the medium  116  is to be accessed, one of the anti-rotational slots  190   a,b  will receive the anti-rotational pin  198  and one of the locating holes  194   a,b  will receive the locating pin  202 . The combination of the anti-rotational slot and locating hole and related pins permits the disk drive to rotate the housing members slightly about the locating pin to provide proper alignment of the housing members in the disk drive prior to or simultaneous with alignment of the medium and attached hub assembly. When the cartridge housing is properly aligned, the disk drive is able to freely rotate the medium without interference form the cartridge housing. As will be appreciated, the anti-rotational slot and pin together inhibit unwanted or excessive rotation of the cartridge assembly about the locating hole and pin as too much displacement of the cartridge can be detrimental to centering of the disk on the disk drive spindle and to servo control. 
     Referring to FIG. 27, the clearance “T 1 ”, between the interior walls  206   a,b  of the slots  190   a,b  and the outer wall  210  of the anti-rotational pin  198 , is greater than the clearance “T 2 ”, between the interior wall  214   a,b  of the locating hole  194   a,b  and the outer wall  211  of the locating pin  202 , to permit the cartridge assembly to engage the anti-rotational pin. In one configuration, the diameters of the anti-rotational and locating pins  198  and  202  are substantially the same and the length of each of the anti-rotational slots  190   a,b  is greater (i.e., at least about 25% but not more than about 50% more) than each of the diameters of the locating holes  194   a,b . The pins  198  and  202  are radially chamfered and/or bullet-nosed to facilitate insertion of the pins into the anti-rotational slot and locating hole respectively. The pins are located at the corners of the cartridge assembly as there is a sufficient cartridge wall thickness at the corners to support the pins. 
     Cartridge assembly alignment in the Z direction is performed by means of the engagement of shoulders  216   a,b,c  with the raised outer wall portions  180   a,b  (FIG. 1) of the housing member (depending on which housing member is facing the shoulders). The annular shoulders  216   a,b  are adjacent to the anti-rotational and locating pins  198  and  202 , respectively, while the shoulder  216   c  is not associated with any pin. The shoulders  216   a-c  contact the wall portions  180   a,b  due to the downward force of a spring located above the housing member  104   a  (not shown), such as a leaf spring, on the opposite housing member  104   a  when housing member  104   b  engages the shoulders. As will be appreciated, only three shoulders are required to perform the alignment even though a system can use four or more such shoulders to contact the wall portions  180   a,b  of the members  104   a,b . When the cartridge assembly is properly positioned in the disk drive, the medium  116  and attached hub assembly  106  are free to rotate in the cartridge assembly. The shoulders or datum features provide a highly efficient method for positioning the cartridge assembly without distortion of the medium  116  such as by clamping. 
     Through proper alignment of the cartridge housing, the disk drive components are able to further align the medium. A central bore  290  in the hub assembly  106  engages a spindle  291  on the disk drive spin motor  292  to align the medium  116  in the x-y directions and an annular ring  293  engages the operational surface  148   b  of the medium  116  to provide alignment in the Z direction, thereby providing proper servo and focus control. A rotary actuator  293  radially moves the optical arm  294  to properly orient the optical head  206  mounted on the end of the arm relative to the operational surface  148   b  of the medium  116 . A sleeve  117  mounted in the disk drive receives the cartridge assembly prior to or during insertion to facilitate insertion and ejection of the cartridge assembly. 
     Referring to FIGS. 26 and 28, the form factor of the disk drive assembly  177  is relatively small. In one configuration, the disk drive assembly  177  has a height “H” ranging from about 10 to about 15 mm, a width “W” ranging from about 35 to about 55 mm, and a length “L” ranging from about 30 to about 50 mm. 
     Referring again to FIGS. 27-29, the spatial relationships among the hub assembly  106 , medium  116 , and components of the cartridge assembly  100  are depicted. As noted, an objective of the present invention is to provide a cartridge assembly that is compatible with the small form factor optical disk drive  177 . To make this possible, a number of issues design considerations typically are addressed. 
     First, the cartridge assembly height “H” (FIG. 3) is preferably substantially minimized. Second, the vertical displacement of the cartridge assembly in the “Z” direction is preferably substantially minimized. To realize a low loading “Z” distance, the exterior surface  180   a,b  of the cartridge assembly and exterior surface  800   a,b  of the corresponding shutter member  108   a,b  are typically coincident (or coplanar) (see FIG.  4 ). This relationship facilitates the ability of the shutter member to expose or cover the bore  290  in the hub assembly and the window  128 . The exterior surface  180   a,b  of the housing members  104   a,b  and the adjacent shutter member exterior surface  800   a,b  must be inserted over the free end of the spindle  291  with a minimal, carefully controlled clearance in the “Z” direction for the straight-in insertion configuration of FIGS. 12-21. This clearance is typically no more than about 0.2 mm. To substantially minimize the loading displacement in the “Z” direction, the exterior surfaces  286   a,b  of the hub members are each preferably established in close proximity to the respective exterior surfaces  180   a,b  and  800   a,b . Accordingly, the thickness of the shutter members is preferably substantially minimized (i.e., is no more than about 0.2 mm) and the hub height is substantially maximized, within the height “H” of the cartridge assembly  100 . 
     Third, medium  116  displacement in the “Z” direction from a nominal starting position within the cartridge is preferably substantially minimized to assure that the hub assembly does not interfere with part of the shutter member during shutter member displacement in either direction (i.e., in shutter member opening or closing). The nominal starting position refers to the medium  116  position when the medium  116  is precisely centered in the annular slot  170 . The medium  116  can translate or move in the “Z” direction internally in the cartridge assembly  100  in the presence of a gravitational or accelerating force. Referring to FIG. 25, the distance (S 1 ) from the interior surface  282   a  of the shutter member  108   a  to the exterior surface  152   a  of the hub member  124   a  is greater than the distance (H d ) between the outer surface of the medium  116  and the interior surface  132   a  of the first housing member  104   a  The width H 2  of the annular slot  170  is preferably minimized while being sufficiently large to assure that the medium  116  can rotate freely, without contacting any internal surface of the cartridge assembly  100  during medium rotation. The foregoing requirements typically require the height of the hub members (as measured from the operational surface  148  of the medium  116  to the maximum thickness point of the hub assembly or given by the equation 50% (H H −T)) to be limited by about 50% of the cartridge thickness “H” reduced by the following: (a) 50% of the medium  116  thickness “T”, (b) 50% of the width H 2  of the annular slot, (c) the shutter member thickness, and (d) manufacturing tolerances. 
     The cartridge assembly  100  can include a feature to prevent a user from inserting the cartridge assembly improperly into the disk drive and thereby damaging the disk drive, cartridge assembly, and/or disk or jamming the cartridge assembly in the disk drive. Referring to FIGS. 3 and 24, the rear end  287  of the cartridge assembly  100  includes one or more reverse lockout slots  289   a,b  which engage the rotary arm  269  as shown in FIG. 24 when the cartridge assembly  100  is inserted in a reverse (or incorrect) orientation into the drive  177 . In this manner, the rotary arm  269  inhibits or restricts the distance of (improper) insertion of the cartridge into the disk drive, thereby protecting the disk drive and other components. The lockout slots  289   a,b  are positioned to engage the rotary arm  269  when the arm  269  is in a home or an at rest position (prior to rotational displacement of the arm by the cartridge assembly). The lockout slot  289   a,b  has an angled face  291   a,b  to accommodate the rotary arm  269  and prevent damage to the unlocking nub  265  during engagement. 
     Referring to FIGS. 2 and 6, the cartridge assembly  100  is manufactured by: placing the ends  300   a,b  of the spring members  112   a,b  in the corresponding spring guide slot  250   a,b  and the spring member in the space between the corresponding surfaces  254   a,b  and  258   a,b ; inserting each pin  261   a,b  into the corresponding hole  259   a,b  of the locking arm; inserting the tab  218   a,b  of each shutter member  108   a,b  in the tab opening  230   a,b  and the inwardly facing tabs  214   a,b  in the slots  222   a,b ; and placing the other end  300   b  of the spring members  300   a,b  into engagement with the corresponding indentation  215   a,b  in the tab  214   b . These steps are repeated in the same order for the other housing member  104   a,b . The tabs  218   a,b  are bent as shown in FIG.  7  and as described above. Next, the medium  116  is positioned such that the centers of the hub members  124   a,b  are roughly aligned with the center of the circular opening  120   a,b  in each housing member  104   a,b . The housing members  104   a,b  are then joined together along a seam line  301  such as by ultrasonic welding, adhesion, ultraviolet techniques, tab-and-slot arrangements, and the like. Alternatively, clips or other suitable connectors can be used to join the housing members together. 
     FIG. 30 depicts an alternative embodiment of a cartridge assembly  600  for a single-sided disk  602  having only one information-containing or operational surface  148  and a blank or nonoperational surface  608 . The one-half of the cartridge assembly  600  that is adjacent to surface  148  is the same as the embodiment set forth above. The other half of the cartridge assembly that is adjacent to surface  608  does not include a shutter, a locking arm, and a spring member. In this embodiment, the other housing member  604  of the cartridge assembly can be solid, with no window for to access the disk or circular opening for the hub assembly. The cartridge assembly is configured such that the cartridge assembly will not fit into the disk drive if the user attempts to insert the cartridge assembly upside down (i.e., with the nonoperational surface facing the optical head). 
     FIGS. 31-33 depict another embodiment of a cartridge assembly  310  that differs from the previous embodiment in the use of a different locking subassembly. The locking subassembly includes a locking slot  312   a,b  (and locking step  314   a,b ) that engages a tab  316  when the shutter member  318   a,b  is in the closed position. This subassembly does not include a locking arm. As will be appreciated, when the shutter member  318   a,b  is opened by the rotary arm, the rotary arm pushes the shutter member slightly inwardly to disengage the tab  316  from the locking step  314  and moves the tab  316  laterally out of and away from the locking slot  312 . When the cartridge assembly  310  is removed from the disk drive and the rotary arm disengaged from the slot  234   a,b , the spring member  112   a,b  forces the trailing edge  315  of the corresponding shutter member  318   a,b  to the closed position against the raised, inner step  320   a,b  of the housing member  314   a,b  and the tab  316  into the locking slot  312  and into engagement with the locking step  314 . Another slot  322  is included at one end of the slot  324  (which permits lateral displacement of the tab  316 ) to permit the tab  316  to be placed into the engagement with the slot  324  (as shown in FIG. 33) during manufacture. 
     FIG. 34 depicts yet another embodiment of a cartridge assembly. The cartridge assembly  350  is similar to the above embodiment with a number of exceptions. For example, the shutter members  354   a,b  include an inwardly facing tab  358   a,b  that differs from the outwardly facing tab  316   a,b  of the shutter members  318   a,b . To accommodate the tab  358   a,b , the slot  362   a,b  has a different configuration than the slot  324   a,b  (see e.g. FIG. 33) of the shutter members  318   a,b . The slot  362   a,b , however, also includes a locking slot  366   a,b  and step  370   a,b . The first and second housing members  374   a,b  also include self-locating features, namely pins  378   a-f  and matching holes  382   a-f  to facilitate alignment of the housing members during manufacture. As will be appreciated, pins  378   d-f  and holes  382   d-f  are on the first housing member  374   a  and are therefore not shown. 
     FIGS. 35-36 depict a further embodiment of a cartridge assembly  400  according to the present invention. The cartridge assembly  400  is similar to the above-noted embodiment of FIGS. 1-7 with a number of exceptions. The cartridge assembly  400  uses a shutter member  402   a,b  having projections  404   a,b  positioned on either side of a flat tab  408 . The tab  408  rides in the slot  412 , with the projections  404   a,b  engaging the step  416  to hold the shutter member in position during movement (and prevent the shutter member from becoming cocked to either side). A shutter cover  420  is fastened to the surface  424  and holds the tab  416  in the slot  412 . The use of a slot that does not pass through the housing member as in the prior embodiment provides additional protection against the tab  408  contacting an operational surface of the medium. However, the use of the bent tab of FIG. 6 permits fewer parts to be used in cartridge assembly manufacture which lowers unit costs and a reduction of the overall cartridge height H with concomitant benefits in the form factor of the disk drive  177 . 
     FIGS. 37-41 depict another embodiment of a cartridge assembly  500  that incorporates a unitary, metal (e.g., stainless steel) cover  504   a,b  on each of the housing members  508   a,b . This embodiment provides additional structural support and a unitary, internal shutter  512  (e.g., stainless steel) for covering simultaneously the circular openings  516   a,b  and windows  520   a,b  from inside of each housing member  508   a,b . This design is different from the two-piece shutter of the previous embodiments that are positioned outside of the housing members (i.e., are external shutters). Each arm  524   a,b  of the shutter has an outwardly facing dimple  528   a,b  that contacts the adjacent interior wall  532   a,b  of the adjacent metal cover  534   a,b  member and thereby reduces friction as the internal shutter  512  moves laterally inside of the cartridge between the open and closed positions. The metal covers are highly electrically conductive and thereby prevent the buildup of static electricity and the electrical attraction of charged particles by the cartridge assembly and also provide a higher strength than plastic for a given thickness. 
     A locking subassembly includes an elastic locking member  536  that is secured by the housing members  508   a,b  at ends  540   a,b  of the locking member  536 . The locking member  536  is biased outwardly to cause the locking projection  544  to engage the rotary arm opening  548  in the shutter  512  when the shutter is in the closed position. When the cartridge assembly is inserted into the disk drive (not shown), the rotary arm (not shown) engages the shutter arm opening  548  and pushes the locking projection  544  inwardly to release the shutter  512 . The rotary arm is then able to move the shutter freely from side-to-side to the open position. As shown in FIG. 38, both of the shutter members  524   a,b  move to the left or right of the circular openings  516   a,b  and windows  520   a,b  to permit the optical head to access both operational surfaces of the medium. When the cartridge assembly is removed from the disk drive, the rotary arm moves the shutter back to the closed position. When the rotary arm disengages the rotary arm opening  548 , the locking projection  544  is reinserted into the opening  548  to lock the shutter  512  in the closed position. 
     FIG. 40 shows the method used to lock the metal cover in position during manufacture. Each side of the metal cover  504   a,b  has downwardly bent tabs  552   a,b  which are inserted into a passage  556  oriented normal to the longitudinal plane of the medium  116  and cartridge assembly walls  560   a,b . A suitable tool is then inserted through the transverse passage  564  (which is located on an end of the cartridge assembly) to deform the tabs  552   a,b  inwardly as shown by the dotted lines and thereby lock the metal cover in position. Accordingly, the assembly is free of welds and adhesives. 
     FIG. 41 depicts the appearance of the shutter before insertion into the cartridge assembly. The shutter is underbent to bias the shutter outwardly when the shutter is inserted into the cartridge assembly as shown in FIG.  30 . After insertion, the shutter members  524   a,b  are moved or rotated to a position substantially parallel to lines  525   a,b . This outward biasing prevents the shutter  512  from contacting the operational surface of the disk. In one configuration, the angle a ranges from about 5 to about 25°. 
     Referring again to FIG. 37, the cartridge assembly is manufactured by aligning the medium  116  with the circular opening  570   a,b  of each housing member  508   a,b , placing the locking member  536  in position, adhering the housing members  508   a,b  together, placing shutter  512  in position, positioning the metal cover in position, inserting the tabs  552   a-d  in the passage  556 , and deforming the tabs as shown in FIG.  41 . 
     A number of variations and modifications of the invention can be used. It would be possible to provide for some features of the invention without providing others. For example, the cartridge assembly can be modified to include an annular labyrinth seal between the hub region of the medium and the interior surfaces of adjacent regions of the first and second housing members, as discussed in Ser. No. 09/315,398, supra. Such a seal can further decrease the likelihood that particles can enter into the interior of the cartridge assembly from the external environment. The leading edge of the cartridge can include one or more recesses that may be used to encode by their number, position, shape, depth, or the like, characteristics of the cartridge or disk such as data density, number of recordable sides, formatting, and the like. The cartridge can be configured to provide for recording on only one surface of the medium, such as by having only one window, one shutter member, and/or being configured to prevent inserting of the cartridge into the disk drive in an attitude other than with the window accessible to drive optics. The side(s) of the cartridge can include one or more grooves for engaging one or more guide rails of the disk drive to assist in desired alignment or positioning of the cartridge with respect to the drive. The cartridge assembly can include vents to cause expulsion of particles located inside of the cartridge assembly during disk rotation. As will be appreciated, when the medium or disk is rotated a pressure differential is created, with the pressure internal to the cartridge assembly being greater than the pressure external to the cartridge assembly. One or more vents would permit particles located inside of the cartridge to be expelled due to the pressure differential. The vent(s) can be of any suitable configuration. Preferably, the vent(s) would include one or more features to inhibit particles from entering the cartridge interior when the pressure is equalized (i.e., when the disk is not in rotation). Such features could selectively open the vent(s) only when the pressure differential is at or above a predetermined threshold. An example would be a flap or cover that is moved outwardly by the pressure differential. 
     The optical storage device and system of the present invention can be used for various types of data storage including storing data for use by computers such as personal computers, laptops, work stations and the like, storage for music or other audio purposes, including storage for MP3 players, digital cameras, motion picture, home video or other video storage purposes, voice data, computer programs and/or data, personal information or data such as medical data, identification, password or encryption/decryption data, credit information, credit or debit card information and the like. Indeed, it is believed that it will be particularly advantageous to provide for use of the storage system and/or medium of the present invention in a wide variety of devices, e.g. to provide for ease of sharing, storing or transmitting of data, e.g. between platforms including, but not limited to devices for play-back, communication or reproduction of data (including, e.g. image, video or music data), such as personal stereo or other personal (or fixed) music reproduction devices, portable or fixed television or video reproduction devices, computer peripheral devices, computer game devices, gaming or gambling devices, still, video or motion picture cameras, automobile stereos or other audio or video devices, purchase or distribution devices such as automatic teller machines or other bank machines, vending machines, and the like. 
     The present invention, in various embodiments, includes components, methods, processes, systems and/or apparatus substantially as depicted and described herein, including various embodiments, subcombinations, and subsets thereof. Those of skill in the art will understand how to make and use the present invention after understanding the present disclosure. The present invention, in various embodiments, includes providing devices and processes in the absence of items not depicted and/or described herein or in various embodiments hereof, including in the absence of such items as may have been used in previous devices or processes, e.g. for improving performance, achieving ease and\or reducing cost of implementation. 
     The foregoing discussion of the invention has been presented for purposes of illustration and description. The foregoing is not intended to limit the invention to the form or forms disclosed herein. Although the description of the invention has included description of one or more embodiments and certain variations and modifications, other variations and modifications are within the scope of the invention, e.g. as may be within the skill and knowledge of those in the art, after understanding the present disclosure. It is intended to obtain rights which include alternative embodiments to the extent permitted, including alternate, interchangeable and/or equivalent structures, functions, ranges or steps to those claimed, whether or not such alternate, interchangeable and/or equivalent structures, functions, ranges or steps are disclosed herein, and without intending to publicly dedicate any patentable subject matter.