Optical disk cartridge and cooperating apparatus

Structure is provided for separately sealing an optical disk cartridge and cooperating apparatus closed when the cartridge and apparatus are not operatively engaged for intended use, and for opening the cartridge and apparatus to each other while jointly closing them from the environment when they are so engaged. The optical disk includes a magnetically attractable hub bearing a compliant annular seal. The disk-containing cartridge is permanently closed except for a central drive-access opening in one wall thereof that is bounded by a circular rim concentrically aligned with the hub seal. Magnetic means on that wall atrract the hub and thereby draw its seal into firm contact with the rim, to seal the opening closed whenever the cartridge is not in use. The cooperating apparatus includes a drive spindle that is bounded by a circular flange also concentrically aligned with the hub seal. Associated mechanism engages the spindle axially with the hub so as to move the flange into contact with the hub seal while moving the seal out of contact with the rim. Encircling the spindle is a resiliently flexible housing member bearing a compliant annular seal concentrically aligned with both the flange and the rim. The housing member is biased toward the flange and rim so as to urge its seal into contact with either the flange, to seal the housing closed whenever the spindle is not engaged with the hub, or the rim, to seal the housing to the cartridge when the spindle is so engaged.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates generally to optical disk cartridges and 
apparatus cooperable therewith, and particularly to an arrangement for 
sealing such a cartridge closed against entry of foreign elements, both 
during storage and handling of the cartridge and during use thereof in 
cooperating apparatus. 
2. Description of the Prior Art 
U.S. Pat. Nos. 4,320,425 and 4,405,136 each disclose a disk cartridge 
having resiliently flexible top and bottom walls, the bottom wall 
including a central opening bounded by a circular lip that resiliently 
presses against a mating annular surface of the hub of a disk inside the 
cartridge, the top wall including an inwardly extending flange that 
resiliently holds the hub in sealing contact with the bottom wall lip and 
the recording portion of the disk spaced from the walls. Operative 
engagement of the cartridge and hub by cooperating disk-drive apparatus 
causes both walls to flex out of contact with the hub and thus free the 
disk for rotation in the cartridge. Such engagement includes supporting 
engagement of the cartridge bottom wall by a stationary part of the 
apparatus and driving engagement of the disk hub by a rotatable drive 
spindle. In U.S. Pat. No. 4,405,136, the stationary part of the apparatus 
supports the cartridge bottom wall through a pneumatic, pressurized, 
annular seal that allows only filtered air from within the apparatus to 
enter the cartridge. 
U.S. Pat. Nos. 3, 609,722, 3,529,301, and 4,394,700 each disclose a disk 
cartridge having top and bottom walls that need not flex in order to be 
sealed to and unsealed from a disk inside the cartridge. In U.S. Pat. No. 
3,609,722, the top and bottom walls each have a central opening bounded by 
a separate, resilient, compressible, annular washer disposed between the 
wall and the disk. Each wall is thus sealed to and spaced from the disk by 
the washer therebetween. Operative engagement of the cartridge and washers 
by cooperating disk-drive apparatus causes the cartridge bottom wall to be 
supported by a stationary part of the apparatus and both washers to be 
compressed by opposing flanges on a rotatable drive spindle. Such 
engagement not only unseals and frees the disk from each cartridge wall; 
it also seals and couples the disk to the drive spindle. In U.S. Pat. No. 
3,529,301, the top and bottom walls each have a central opening bounded by 
an annular flange formed by the wall itself so as to mate with a facing 
surface on the disk hub. Each wall is thus sealed to and spaced from the 
disk by the flange thereon. The disk is restrained from moving relative to 
the walls by a spring-loaded brake that normally bears against the disk 
periphery. Operative engagement of the cartridge and disk hub by 
cooperating disk-drive apparatus causes the brake to be withdrawn from the 
disk and the hub to be pushed upwardly away from each wall flange by a 
rotatable drive spindle. Such engagement frees the disk contact with the 
cartridge walls and sealingly couples the disk to the spindle. In U.S. 
Pat. No. 4,394,700, the cartridge bottom wall has a central opening 
bounded by an annular flange which mates with a corresponding flange on 
the disk hub. Mounted on or near the wall flange is a plurality of 
spring-loaded clamping members which normally press the wall flange and 
hub flange together so as to seal the hub securely to the bottom wall. 
Operative engagement of the cartridge and hub by cooperating disk-drive 
apparatus actuates the clamping members, against their spring-loading, to 
unclamp the flanges and thus free the disk for rotation, while a rotatable 
spindle in the apparatus drivingly engages the hub. 
Prior-art schemes such as those described above may have been satisfactory 
in some applications, but there remains a need for an improved arrangement 
by which an optical disk permanently contained in a cartridge is protected 
against damage or impairment from other objects or contaminants during 
storage, handling, and use of the disk. Such an arrangement should both 
restrain the disk from moving inside the cartridge and seal the cartridge 
closed whenever the cartridge is not operatively positioned for its 
intended use in cooperating write/read apparatus, but should readily 
accommodate a disk-drive member of such apparatus and free the disk for 
rotation thereby whenever the cartridge is so positioned. Such an 
arrangement should also provide ready optical access to the 
information-storage medium of the disk by an optical write/read head in 
the apparatus when the cartridge is operatively positioned therein. 
Preferably these things should be accomplished by an arrangement that is 
more efficient, reliable, and durable over the expected life of the 
cartridge, and simpler and less costly to manufacture, than those employed 
heretofore. 
SUMMARY OF THE INVENTION 
Accordingly, an object of the present invention is to provide a more 
efficient, reliable, and durable way of protecting an optical disk in a 
cartridge against possible damage or impairment by other elements during 
storage, handling, and use of the disk. 
This object is achieved by the invention herein claimed. The invention 
embraces novel features of both a disk-containing cartridge and apparatus 
cooperable therewith. 
The invention thus finds utility in an optical disk cartridge adapted for 
use in cooperating write/read apparatus having a rotatable drive spindle 
and a movable optical head. The cartridge contains a rigid optical disk 
including a flat information-storage medium and a magnetically attractable 
hub with a compliant annular seal thereon projecting from the medium. The 
cartridge comprises first and second substantially rigid, opposed walls 
that are fixedly spaced from and substantially coextensive and parallel 
with each other, the disk being disposed between and substantially 
parallel with those walls. The first wall has a round opening therein 
concentric with the disk hub to provide access thereto by the drive 
spindle of the cooperating apparatus. The opening is bounded by a circular 
rim aligned with the annular hub seal. The first wall bears magnetic means 
near the rim for attracting the hub and thereby drawing the hub seal into 
sealing contact with the rim, to retain the disk in stationary, sealed 
relationship with the first wall when the cartridge is not operatively 
positioned in the cooperating apparatus. The hub is engageable and axially 
movable by the apparatus drive spindle away from the first wall, in 
opposition to the magnetic means, to urge the disk out of its stationary, 
sealed relationship and thereby render the disk free to rotate when the 
cartridge is operatively positioned in the cooperating apparatus. In the 
illustrated embodiment, the cartridge second wall has a window therein 
aligned with a portion of the disk medium to provide optical access to the 
medium by the optical head of the cooperating apparatus. The window has a 
thin, planar sheet of transparent material extending thereacross to 
protect the medium from exterior contaminants without interfering with 
optical access. Preferably, a closure member is mounted on the second wall 
for movement from a closed position covering the window to an open 
position uncovering the window, to protect the window and thereby further 
protect the medium when the cartridge is not in use in the cooperating 
apparatus, and to permit optical access when the cartridge is in such use. 
The invention also finds utility in apparatus for recording and retrieving 
information on an optical disk contained in a cartridge, the disk having a 
flat, substantially rigid information-storage medium and a magnetically 
attractable hub with a compliant annular seal thereon projecting from the 
medium, the cartridge including first and second opposed, parallel, 
rigidly spaced walls disposed on opposite sides of the disk, the first 
wall having an opening therein bounded by a circular rim concentrically 
aligned with the annular hub seal and magnetic means near the rim for 
attracting the hub and thereby drawing the hub seal into sealing contact 
with the rim, to retain the disk in stationary, sealed relationship with 
the first wall when the cartridge is not in use. Such apparatus comprises 
means for supporting the cartridge in an operative position; a drive 
spindle rotatable about an axis and engageable with the disk hub, the 
spindle having a circumferential flange thereon that is concentrically 
aligned with the annular hub seal when the cartridge is in its operative 
position, the spindle being mounted for movement along said axis through 
the first wall opening and toward the second wall when the cartridge is in 
said position; and means for moving the drive spindle along said axis 
through the first wall opening and toward the second wall into engagement 
with the hub, so as to push the hub away from the first wall, in 
opposition to the magnetic means thereon, and thereby urge the disk out of 
its stationary, sealed relationship, to render the disk freely rotatable 
relative to the first wall when the cartridge is in use, the flange moving 
concurrently into sealing contact with the hub seal to seal the disk to 
the spindle when the disk is not sealed to the first wall. In the 
illustrated embodiment, the apparatus has an enclosure including a movable 
member with a compliant annular seal thereon encircling the spindle, the 
enclosure member seal being concentrically aligned with the circular rim 
when the cartridge is in its operative position. The enclosure member seal 
moves parallel with the spindle axis into sealing contact with the rim, as 
the flange moves into sealing contact with the hub seal, to seal the first 
wall to the enclosure member when the first wall is not sealed to the 
disk. The enclosure member seal also is concentrically aligned with the 
spindle flange and is in sealing contact therewith, when the flange is not 
in sealing contact with the hub seal, to seal the enclosure member to the 
spindle when the enclosure member is not sealed to the first wall. The 
apparatus also has means for rotating the spindle about its axis, to 
impart rotation to the disk when the spindle has been engaged with the 
hub, and an optical head, mounted for close traversing movement relative 
to an optical access window in the cartridge second wall facing a portion 
of the disk medium, for optically recording and retrieving information on 
the medium through the window when said rotation has been imparted to the 
disk. 
An advantage of this invention is that it achieves its aforementioned 
object by an arrangement which is especially suitable for protecting 
optical disks capable of high-density information storage, and which is 
reasonably simple and practical to manufacture and use. 
The invention, and its objects and advantages, will become more apparent in 
the detailed description of the preferred embodiment presented below.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
Because certain parts of disk cartridges and associated apparatus are well 
known, the following description is directed in particular to those 
elements forming, cooperating directly with, or relating to the present 
invention. Elements not specifically shown or described herein are 
selectable from those known in the relevant art. 
Illustrated in FIG. 1, in exploded form, in an optical disk cartridge 10 
constructed in accordance with the preferred embodiment of the invention. 
Cartridge 10 is adapted to contain, permanently, an optical disk 12 
comprising a circular, substantially rigid and flat, information storage 
medium 14 having upper and lower sides 16 and 18, respectively, with a 
solid, magnetically attractable, ferrous-metal hub 20 bonded to and 
projecting from the lower side. On the bottom side of hub 20 are a 
compliant annular seal 22 and, radially inward thereof, a flexure mount 
guide 24. On guide 24 are a plurality of (three shown) circumferentially 
spaced flexure mounts 26, each holding a resiliently flexible pin, or 
flexure, 28. 
Cartridge 10 comprises a generally square-shaped housing 30 formed by six 
orthogonally joined, substantially rigid walls 32, 34, 36, 38, 40, and 42, 
which together define a cavity 44 for accommodating the disk. Opposed top 
and bottom walls 32 and 34 are substantially parallel and coextensive with 
each other, and are fixedly spaced from each other by opposed side walls 
36 and 38 and opposed end walls 40 and 42. Disk 12 is disposed between and 
substantially parallel with the cartridge top and bottom walls so that top 
wall 32 and bottom wall 34 face the disk upper and lower sides 16 and 18 
respectively. 
The cartridge bottom wall has a central drive-access opening 46 therein 
substantially concentric with the disk hub. As shown more clearly in FIGS. 
3 and 4, opening 46 is bounded by a circular rim 48 having upper and lower 
seal-contacting lips 50 and 52, the upper lip 50 being concentrically 
aligned with the hub annular seal 22. On bottom wall 34 near rim 48 are 
magnetic means 54 comprising a plurality of (four shown) circumferentially 
spaced magnetic clips 56, each holding a permanent magnet 58. When the 
cartridge is not in use in cooperating apparatus, the magnetic means 54 
attracts disk hub 20 so as to draw hub seal 22 into sealing contact with 
rim upper lip 50 and thereby retain the disk in stationary, sealed 
relationship with the bottom wall. The bottom wall opening 46 is thus 
sealed closed whenever the cartridge is not being used as intended. 
The cartridge top wall 32 has an optical-access window 60 therein facing a 
portion of disk upper side 16. Window 60 has a thin, planar sheet 62 of 
transparent, preferably non-birefringent, protective material extending 
across and sealed to a window frame 64, to prevent exterior contaminants 
from passing through the window to the cartridge cavity 44, but without 
interfering with needed optical access to the disk medium. The top wall 
window is thus sealed closed at all times. On top wall 32 over window 60 
is a movable closure member 66 slidably mounted between a pair of lateral 
retention rails 68 for movement from a normally closed position covering 
the window to an open position uncovering the window. Closure member 66 
thus protects window sheet 62 and thereby further protects the disk medium 
from possible damage or impairment by external elements when member 66 is 
in its closed position, which is its normal position whenever the 
cartridge is not being used in cooperating apparatus. When the cartridge 
is being used, however, movement of member 66 to its open position permits 
the needed optical access to medium 14 through transparent window sheet 
62. 
It will thus be appreciated that, since there are no openings in any of the 
cartridge housing walls other than drive-access opening 46 and 
optical-access window 60, both of which are sealed closed at least when 
the cartridge is not in use in cooperating apparatus, the entire cartridge 
is closed to possible entry of deleterious elements whenever the cartridge 
is not being used as intended. 
Cooperating apparatus in which cartridge 10 may be used is partially 
illustrated in FIG. 2. The apparatus is designated generally by the 
numeral 70. It comprises a rectangular-shaped housing 72 formed by a 
horizontal base plate 74, vertical side and rear-end walls 76, 78, and 80, 
a horizontal top wall 81, and a vertical front-end wall (not shown) with 
an access door (also not shown) movably mounted thereon for loading and 
unloading the cartridge. Inside housing 72 is a horizontal reference plate 
82 spaced from base plate 74 and joined to the vertical walls as shown. On 
top of plate 82 adjacent to each side wall is a pair of 
cartridge-receiving guides 84, which together provide a means 90 for 
receiving the cartridge and supporting it in an operative position. When 
in that position, the cartridge top and bottom walls are substantially 
horizontal and face the apparatus top wall and reference plate 
respectively. 
In plate 82 between the opposing pairs of guides 84 is a circular opening 
92. Mounted on and sealed to plate 82 around the periphery of opening 92 
is a circular, resiliently flexible, spring-like, cover plate 94 having a 
central round hole 96 therein concentric with opening 92. Plate 94 extends 
generally horizontally across opening 92 so as to cover all of that 
opening except the central part thereof within hole 96. Plate 94 is made 
to function in the manner of a large Belleville-type spring washer, and as 
mounted is biased so that the radially inner portion thereof around the 
periphery of hole 96 exerts spring force in a generally upward direction. 
On that radially inner portion of plate 94 around hole 96 is a compliant 
annular seal 98 which is concentrically aligned with rim lower lip 52 when 
the cartridge is in its operative position thereabove. 
Mounted on base plate 74 is a disk-drive mechanism 100 including an 
electric drive motor 102 with a drive spindle 104 projecting upwardly 
therefrom through hole 96 and toward disk hub 20 in operatively positioned 
cartridge 10. As shown more clearly in FIGS. 3-5, spindle 104 is 
concentric with both hole 96 and hub 20. Spindle 104 comprises three 
functional components: (1) a central shaft 106 configured to engage the 
flexures 28 on hub 20 for the purpose of centering disk 12 and cartridge 
10 relative to the spindle; (2) a circumferential flange 108 having upper 
and lower seal-contacting lips 110 and 112, the upper lip 110 being 
concentrically aligned with hub annular seal 22, the lower lip 112 being 
concentrically aligned with plate annular seal 98; and (3) magnetic 
coupling means 114 near flange 108, including a magnetic ring 116 and an 
annular pole piece 118, for magnetically coupling the spindle to the hub. 
Spindle 104 is both rotatable about and translatable along its vertical 
axis A. The spindle is rotated at desired disk-drive speed by operation of 
motor 102. The spindle is translated toward and away from the disk hub 20 
by operation of an electromechanical actuator 120. As shown in FIGS. 3 and 
5, actuator 120 comprises a solenoid 122, including a spring-biased 
plunger 123, and a two-armed lever 124. One arm 124a of lever 124 is 
operatively engaged with the solenoid plunger; the other arm 124b is 
coupled to the motor. Energization of the solenoid actuates plunger 123 
against its spring bias and thereby causes counterclockwise rotation of 
the lever and consequent upward movement of both motor and spindle towrd 
the disk hub. Susequent de-energization of the solenoid causes 
spring-assisted rotation of the lever clockwise and thereby effects 
downward movement of the motor and spindle away from the hub. 
FIGS. 2 and 3 show the disk-drive mechanism in its unenergized condition, 
wherein motor 102 and spindle 104 are disposed in their fully lowered, 
at-rest positions. When so positioned, the spindle flange lower lip 112 is 
in firm sealing contact with plate annular seal 98, such contact being 
maintained by the upward bias of plate 94. Since there are no openings in 
the spindle radially inward of flange 108, the entire circular opening 92 
in plate 82 is sealed closed by cover plate 94, seal 98, and the spindle. 
Spring-like cover plate 94 thus significantly serves as a movable 
enclosure member of apparatus 70. 
Shown in FIGS. 3 and 5 are a pair of horizontally space, vertical internal 
walls 126 and 128 that extend between and join with plates 74 and 82 and 
walls 76 and 78 to enclose a chamber 130 which accommodates disk-drive 
mechanism 100 and actuator 120. With the foregoing cooperation of plate 
94, seal 98, and lip 112, that whole chamber is thus sealed closed against 
possible entry of deleterious external elements whenever the motor and 
spindle occupy their lower, at-rest positions shown in FIGS. 2 and 3. 
Preferably, an opening 132 is provided in plate 74, between walls 126 and 
128, for receiving a filter 134 which will permit only filtered air to 
enter chamber 130. 
FIG. 3 also shows the cartridge 10 supported in its operative position 
above the disk-drive mechanism. As seen in that figure and in FIGS. 3a and 
4, with the mechanism not yet energized, the spindle is still sealed to 
cover plate 94, and the disk is still sealed to cartridge bottom wall 34, 
whereby the chamber 130 and cartridge 10 are each separately closed from 
the environment. 
FIGS. 5-7 show the disk-drive mechanism in its energized condition, with 
spindle 104 moved to its fully raised position in driving engagement with 
disk hub 20. During upward movement of the spindle to that position from 
its lower position shown in FIG. 3, the upward bias of cover plate 94 
causes annular seal 98 thereon to follow spindle flange lower lip 112, and 
thus remain in sealing contact therewith, until flange lower lip 112 
reaches the plane of cartridge rim lower lip 52. Before that plane is 
reached, however, spindle shaft 106 engages hub flexures 28 so that disk 
12 and cartridge 10 together are accurately centered on the spindle. Then, 
when flange lower lip 112 does reach said plane, the plate annular seal is 
intercepted by the rim lower lip, and thereafter remains in firm sealing 
contact therewith as the spindle continues on through opening 46 into 
further engagement with hub 20. As flange lower lip 112 thus moves out of 
contact with plate annular seal 98, the flange upper lip 110 moves into 
sealing contact with hub annular seal 22, and annular pole piece 118 
engages the lowermost surface of hub 20 radially inward of seal 22 to 
magnetically couple the spindle to the hub. Further upward movement of 
spindle 104 then causes the spindle to push hub 20 upwardly away from 
cartridge bottom wall 34 and toward top wall 32. In so doing, the upward 
pushing force of spindle 104 overcomes the downward attracting force of 
magnetic means 54, and thereby urges hub 20 away from magnetic clips 56 
and hub seal 22 away from rim upper lip 50. Disk 12 is thus moved out of 
its stationary, sealed relationship with bottom wall 34, thereby freeing 
the disk for rotation relative to that wall; and disk upper side 16 is 
thus moved closer to top wall 32, thereby rendering that side of disk 
medium 14 more optically accessible through window 60. With the disk thus 
properly positioned for rotation and optical recording or playback, the 
upward movement of spindle 104 is stopped; and with the spindle already 
magnetically coupled to the hub, motor 102 is energized to rotate the 
disk. As seen in FIGS. 5-7, with the mechanism now energized and driving 
the disk, the cartridge bottom wall 34 is no longer sealed to the disk but 
instead is sealed to the apparatus cover plate 94, and the spindle 104 is 
no longer sealed to the cover plate but instead is sealed to the disk, 
whereby the cartridge 10 and apparatus chamber 130 are open to each other 
but the two together are closed from the outside world (except for air 
admitted through filter 134). 
As depicted in FIG. 2, apparatus 70 also includes a laser write/read 
optical head 138, mounted in housing 72 for close traversing radial 
movement relative to cartridge window 60, for optically recording and 
retrieving information on disk medium 14 through transparent window sheet 
62 when closure member 66 is open and disk 12 is rotating. 
Although not shown, the apparatus may further include a device for 
automatically unlocking and moving closure member 66 from its normally 
closed position to its open position in response to insertion of the 
cartridge into its operative position. Similarly, provision may be made, 
e.g., by a return spring, in the apparatus or in the cartridge itself for 
returning the closure member to its closed (and locked) position upon 
removal of the cartridge. Also, means may be provided for automatically 
energizing and de-energizing disk-drive solenoid 122 in response to 
closing and opening, respectively, of the apparatus access door when a 
cartridge is in its operative position. 
FIGS. 3 and 5-7 each show the cartridge supported in its operative position 
with closure member 66 moved to its open position. As seen in FIGS. 6 and 
7, a resilient spring catch 140 is provided on cartridge top wall 32 to 
engage detents 142 and 144 on closure member 66 for the purpose of 
releasably holding member 66 in its open and closed positions, 
respectively. FIG. 3 shows optical head 138 positioned over the radially 
outer end of cartridge window 60. FIG. 5 shows head 138 at a point along 
its traversing radial movement path over window 60. FIG. 6 shows head 138 
disposed successively at the outer end and near the inner end of said 
path. 
Upon completion of a recording or playback operation, optical head 138 is 
returned to its initial position shown in FIG. 2, motor 102 is 
de-energized to terminate its drive input to disk 12, solenoid 122 is 
de-energized, and magnetic coupling means 114 becomes uncoupled from the 
disk as the drive spindle returns to its lower, at-rest position shown in 
FIG. 3. As mentioned above, solenoid 122 may be de-energized and the 
spindle returned to its rest position in response to opening of the 
apparatus access door. Both cartridge 10 and chamber 130 are thus restored 
to their separately closed conditions depicted in FIG. 3, wherein magnetic 
means 54, hub seal 22, and rim upper lip 50 cooperate to maintain disk 12 
in stationary, sealed relationship with cartridge bottom wall 34, and 
wherein biased cover plate 94, plate seal 98, and flange lower lip 112 
cooperate to maintain spindle 104 in firmly sealed relationship with 
apparatus reference plate 82. The cartridge now can safely be withdrawn 
from the receiving and supporting means 90 and removed from the apparatus. 
Preferably, as suggested above, cartridge closure member 66 is 
automatically returned to its normally closed position covering window 60 
as the cartridge is removed. 
It will thus be seen that the present invention, in comparison with the 
prior art, provides a significantly more efficient, reliable, and durable 
way of protecting an optical disk in a cartridge against damage or 
impairment by other elements during all stages of storage, handling, and 
use of the disk. 
The invention has been described in detail with particular reference to the 
preferred embodiment thereof, but it will be understood that variations 
and modifications can be effected within the spirit and scope of the 
invention.