U.S. patent application number 09/315398 was filed with the patent office on 2002-08-01 for removable optical storage device and system.
Invention is credited to BRAITBERG, MICHAEL F., REDMOND, IAN R., VOLAN, GREGORY D., VOLK, STEVEN B..
Application Number | 20020101816 09/315398 |
Document ID | / |
Family ID | 23224232 |
Filed Date | 2002-08-01 |
United States Patent
Application |
20020101816 |
Kind Code |
A1 |
BRAITBERG, MICHAEL F. ; et
al. |
August 1, 2002 |
REMOVABLE OPTICAL STORAGE DEVICE AND SYSTEM
Abstract
A user-removable optical data storage system is provided. A
rotatable first-surface medium is enveloped in a cartridge. The
cartridge provides relatively large data capacity such as about
0.25 Gbytes or more despite a relatively small size such as about
35 mm.times.35 mm.times.3 mm. Preferably the cartridge
substantially seals the data surfaces of the medium when the
cartridge is withdrawn from a drive and at least a portion of one
surface is automatically exposed to the objective of an optics arm
when said cartridge is inserted in the drive. Tracking involves
rotating an optic arm about an axis parallel to the disk rotation
axis. Focus can involve pivoting the arm about an axis parallel to
the disk surface.
Inventors: |
BRAITBERG, MICHAEL F.;
(BOULDER, CO) ; VOLK, STEVEN B.; (BOULDER, CO)
; VOLAN, GREGORY D.; (LONGMONT, CO) ; REDMOND, IAN
R.; (PRINCETON, NJ) |
Correspondence
Address: |
David E. Steuber
Skjerven, Morrill, MacPherson,
Franklin and Friel LLP
25 Metro Drive, Suite 700
San Jose
CA
95110
US
|
Family ID: |
23224232 |
Appl. No.: |
09/315398 |
Filed: |
May 20, 1999 |
Current U.S.
Class: |
720/736 ;
G9B/17.048; G9B/23.033; G9B/23.042; G9B/7.055; G9B/7.108;
G9B/7.139 |
Current CPC
Class: |
G11B 7/00745 20130101;
G11B 17/167 20130101; G11B 17/057 20130101; G11B 7/24097 20130101;
G11B 23/0308 20130101; G11B 7/123 20130101; G11B 7/007 20130101;
G11B 7/08576 20130101; G11B 31/006 20130101; G11B 7/135 20130101;
G11B 7/127 20130101 |
Class at
Publication: |
369/291 |
International
Class: |
G11B 003/70; G11B
005/84; G11B 007/26 |
Claims
What is claimed is:
1. A user-removable optical data recording cartridge comprising: a
first-surface optical recording medium having at least a first
recordable and readable surface; a cartridge body, with said medium
positioned therein, so as to permit rotation of said medium about a
first axis, said cartridge body defining at least a first window
for permitting optical access to a portion of said medium for
reading and writing on said medium as said medium is rotated;
wherein said portion of said medium includes at least an arcuate
region to accommodate light from an objective end of an optics arm
which is rotatable about an axis, different from said first
axis.
2. A cartridge as claimed in claim 1 wherein said cartridge body
includes at least a first window region over at least said arcuate
region, covered by a plate which is transparent at a first
wavelength.
3. A cartridge as claimed in claim 1 wherein said cartridge body is
configurable between a first configuration substantially enclosing
said recording medium and a second configuration exposing a portion
of said medium for reading and writing on said medium as said
medium is rotated.
4. A cartridge as claimed in claim 3 wherein said portion of said
medium exposed in said second configuration is a portion of said
first surface of said medium and wherein a second, opposed surface
of said medium is substantially unexposed in said second
configuration.
5. A cartridge as claimed in claim 4 wherein said cartridge body is
further configurable to a third configuration wherein said a
portion of said second surface of said medium is exposed in said
third configuration.
6. A cartridge as claimed in claim 1 wherein portions of both said
first surface and said second surface are exposed when said
cartridge body is in said second configuration.
7. A cartridge as claimed in claim 3 wherein said cartridge
comprises a first window for exposing a portion of said medium and
a first shutter movable from a first position when said cartridge
is in said first configuration to a second position when said
cartridge is in said second configuration.
8. A cartridge as claimed in claim 7 wherein said window has a
transverse extent sufficient to accommodate at least partial
insertion of said objective end of an optics arm through said
window.
9. A cartridge as claimed in claim 1 further comprising a plurality
of recesses formed in an edge surface of said cartridge for
encoding characteristics of said medium.
10. A cartridge as claimed in claim 1 having a width and depth of
about 35 mm and thickness of about 3 mm and wherein at least said
first recordable and readable surface of said medium provides a
data capacity of at least about 0.25 Gbytes.
11. A method for optically recording data, comprising: providing a
user-removable cartridge having a optical first-surface recording
medium mounted therein for rotation about a first axis, configured
to provide optical access to at least a first arcuate region of
said medium, positioning said cartridge in a location adjacent an
optical arm, said optical arm having an objective end and rotatable
about a second axis,; rotating said optical arm about said second
axis to position said objective end aligned with a plurality of
desired arcuate positions along said arcuate region; rotating said
medium about said first axis to position a plurality of desired
medium positions in alignment with said objective end; and
providing laser light along said optical arm to said objective end
for diverting from said objective end to said plurality of desired
medium positions.
12. A method, as claimed in claim 11 wherein said cartridge
provides a first shutter movable, via a mechanical linkage, from a
first position, substantially sealing said medium in said
cartridge, to a second position, exposing at least said first
arcuate region of said medium.
13. A method, as claimed in claim 12, wherein, in response to said
positioning, said linkage automatically moves said shutter to said
second position.
14. A method for optically reading comprising: providing a
user-removable cartridge having a optical first-surface
pre-recorded medium mounted therein for rotation about a first
axis, configured to provide optical access to at least a first
arcuate region of said medium, positioning said cartridge in a
location adjacent an optical arm, said optical arm having an
objective end and rotatable about a second axis; rotating said
optical arm about said second axis to position said objective end
aligned with a plurality of desired arcuate positions along said
arcuate region; rotating said medium about said first axis to
position a plurality of desired medium positions in alignment with
said objective end; and providing laser light along said optical
arm to said objective end for diverting from said objective end to
said plurality of desired medium positions; and detecting at least
a first characteristic of light reflected from said desired medium
positions.
15. A user-removable optical data recording cartridge comprising: a
first-surface optical recording medium having at least a first
optically readable surface; means for covering said medium, so as
to permit rotation of said medium about a first axis; means for
permitting optical access to a portion of said medium for reading
data on said medium as said medium is rotated; wherein said portion
of said medium includes at least an arcuate region to accommodate
light from an objective end of an optics arm which is rotatable
about a axis, different from said first axis.
16. A cartridge as claimed in claim 15 wherein data is pre-recorded
onto said medium.
17. A cartridge as claimed in claim 15 wherein said medium is a
recordable medium.
18. A cartridge as claimed in claim 15, wherein said means for
permitting optical access includes means for covering, configurable
between a first configuration substantially enclosing said
recording medium and a second configuration exposing said portion
of said medium.
19. A cartridge, as claimed in claim 18, wherein said portion of
said medium exposed in said second configuration is a portion of
said first surface of said medium and wherein a second surface is
substantially unexposed in said second configuration.
20. A cartridge, as claimed in claim 18, wherein said means for
covering is further configurable to a third configuration wherein
said a portion of said second surface of said medium is exposed in
said third configuration.
21. A cartridge, as claimed in claim 15 wherein portions of both
said first surface and said second surface are exposed when said
means for covering is in said second configuration.
22. A cartridge, as claimed in claim 18, wherein said means for
covering comprises a first window for exposing said portion of said
medium and a first means for sealing.
23. A cartridge, as claimed in claim 22 wherein said means for
sealing comprises a substantially transparent plate.
24. A cartridge as claimed in claim 22 wherein said means for
sealing is movable from a first position when said means for
covering is in said first configuration to a second position when
said means for covering is in said second configuration.
25. A cartridge as claimed in claim 22 wherein said window has a
transverse extent sufficient to accommodate at least partial
insertion of said objective end of an optics arm through said
window.
26. A cartridge as claimed in claim 15 further comprising means for
encoding characteristics of said medium.
27. A cartridge as claimed in claim 15 having a width and depth of
about 35 mm and thickness of about 3 mm and wherein each of said
first and second recordable and readable surfaces of said medium
provides a data capacity of at least about 0.25 Gbytes.
28. Apparatus for optically recording data, comprising: a cartridge
having a optical first-surface recording medium mounted therein for
rotation about a first axis, and defining a first shutter movable,
via a mechanical linkage, from a first position, substantially
sealing said medium in said cartridge, and a second position,
exposing at least a first arcuate region of said medium, means for
assisting in positioning said cartridge in a location adjacent an
optical arm, said optical arm having an objective end and rotatable
about a second axis, wherein, in response to said positioning, said
linkage automatically moves said shutter to said second position;
means for rotating said optical arm about said second axis to
position said objective end aligned with a plurality of desired
arcuate positions along said arcuate region; means for rotating
said medium about said first axis to position a plurality of
desired medium positions in alignment with said objective end; and
means for providing laser light along said optical arm to said
objective end for diverting from said objective end to said
plurality of desired medium positions.
29. Apparatus for reading optical data, comprising: a cartridge
having an optical first-surface medium mounted therein for rotation
about a first axis, and defining a first window exposing at least a
first arcuate region of said medium, means for assisting in
positioning said cartridge in a location adjacent an optical arm,
said optical arm having an objective end and rotatable about a
second axis; means for rotating said optical arm about said second
axis to position said objective end along said arcuate region;
means for rotating said medium about said first axis to position a
plurality of desired medium positions in alignment with said
objective end; means for providing laser light along said optical
arm to said objective end for diverting from said objective end to
said plurality of desired medium positions; and means for detecting
changes in at least a first optical characteristic of light
reflected from said medium.
30. Apparatus as claimed in claim 29 wherein said medium contains
pre-recorded data.
31. A data recording medium comprising: a substrate; a optical
recording layer coupled to said substrate, wherein said optical
recording layer includes at least a first optical recording medium
film; wherein said recording layer and substrate are fashioned as a
rotatable disk, said recording layer positioned with respect to
said substrate such that said recording layer can be optically read
or written by providing a read or write beam, having a first
wavelength, to an operational surface of said disk, without the
need for said read or write beam to traverse through said
substrate, and such that said optical recording medium film is
spaced a distance from said operational surface which is less than
about fifty times said wavelength, whereby said data recording
medium is a first surface medium.
32. A data recording medium, as claimed in claim 31, wherein said
recording medium film is a thermally-written, optically-sensed
material.
33. A data recording medium, as claimed in claim 31, wherein said
recording medium film is an optically-written material.
34. A data recording medium, as claimed in claim 31, wherein said
recording medium film is substantially electrically conductive.
35. A data recording medium, as claimed in claim 31, wherein said
recording medium is substantially panchromatic, permitting read or
write operations at wavelengths between about 400 nm and about 1100
nm.
36. A data recording medium, as claimed in claim 31, wherein said
recording layer comprises at least a second film selected from the
group consisting of: a reflective film; a dielectric film; and an
adhesion film.
37. A data recording medium, as claimed in claim 31, wherein said
recording medium film is at least about 20 micrometers from said
operational surface.
38. A data recording medium, as claimed in claim 31, wherein said
recording medium is grooved.
39. A data storage medium comprising: a substrate; a optical data
storage layer coupled to said substrate, wherein said optical data
storage layer includes at least a first optical data film; wherein
said data storage layer and substrate are fashioned as a rotatable
disk, said data storage layer positioned with respect to said
substrate such that said data storage layer can be optically read
by providing a read beam, having a first wavelength, to an
operational surface of said disk, without the need for said read
beam to traverse through said substrate, and such that said optical
data film is spaced a distance from said operational surface which
is less than about fifty times said wavelength, whereby said data
storage medium is a first surface medium.
40. A data storage medium, as claimed in claim 39, wherein at least
some data is pre-recorded on said data film.
41. A data storage medium, as claimed in claim 40, wherein at least
a portion of said data film is writeable.
42. A data storage medium, as claimed in claim 39, wherein at least
some servo features are pre-recorded.
43. A data storage medium, as claimed in claim 42, wherein said
servo features include features selected from the group consisting
of: sector marking features; track-following features;
identification information; read test features; or write test
features.
44. A drive for reading data on an optical media disk, said disk
defining a plane, comprising: a spin drive for rotating said disk
about a first axis; an arm, having an objective end, mounted for
rotating said arm about a tracking axis to position said objective
end in alignment with any of a plurality of radial positions of
said disk, said tracking axis being substantially parallel to and
spaced from said first axis said objective end being spaced from
said disk a distance of at least about 50 micrometers; and a laser
light source configured to provide laser light along a path to said
objective end of said arm and thence to said disk; and an optical
detector which detects light reflected from said disk.
45. A drive, as claimed in claim 44, wherein said arm is further
mounted for controllably moving said objective end along a path to
adjust the distance of said objective end from said disk for
focusing said laser light.
46. A drive, as claimed in claim 44, wherein moving said arm for
focusing is performed while maintaining said objective end and said
laser light source in a substantially constant spatial relationship
with respect to one another.
47. A drive, as claimed in claim 44, wherein said arm is mounted to
provide for translation of said arm in a direction substantially
parallel to said first axis.
48. A drive, as claimed in claim 44, wherein said arm is mounted to
provide for pivoting of said arm about an axis substantially
parallel to the plane of said disk.
49. A drive, as claimed in claim 44, wherein said drive has a mass
less than or equal to about 0.05 kg.
50. A drive, as claimed in claim 44, wherein said drive fits within
a rectangular envelope having a thickness less than or equal to
about 10 mm.
51. A drive, as claimed in claim 44, wherein said drive fits within
a rectangular envelope having a width less than or equal to about
60 mm.
52. A drive, as claimed in claim 44, wherein said drive fits within
a rectangular envelope having a depth of less than or equal to
about 50 mm.
53. A drive, as claimed in claim 44 further comprising a drive
controller interface, wherein said drive controller interface is a
universal serial bus interface.
54. An optical data drive, comprising: a spin drive for rotating an
optical media disk about a first axis, said disk defining a plane;
an arm, having an objective end, said arm movable to position said
objective end in alignment with any of a plurality of radial
positions of said disk; a laser light source configured to provide
laser light along a path to said objective end of said arm and
thence to said disk; and a universal serial bus data interface for
communicating data between said drive and a host device.
55. An optics assembly for use in conjunction with an optical data
disk, comprising: a vertical cavity surface emitting laser (VCSEL);
a light detector; and an optical relay system which guides at least
some laser light from said VCSEL to a selectable region of said
optical data disk and which guides at least a portion of reflected
light from said optical data disk to said light detector.
56. An optics assembly as claimed in claim 55 wherein said VCSEL
and said light detector are formed on a single integrated circuit
substrate.
57. An optics assembly as claimed in claim 55 wherein said VCSEL
and said light detector are mounted on a single substrate.
58. Apparatus for use in connection with optical data storage,
comprising: a storage medium wherein data bits written thereon bits
can be distinguished using reflected light, reflected from said
storage medium; a laser light source; a detector; an optical relay
system which guides at least some laser light from said laser light
source to a selectable region of said storage medium and which
guides at least a portion of said reflected light from said storage
medium to said detector; wherein said laser light source and said
detector are formed on a single integrated circuit substrate.
59. Apparatus, as claimed in claim 58, wherein said laser light
source includes a surface emitting laser.
60. Apparatus, as claimed in claim 58, wherein said laser light
source includes at least a first vertical cavity surface emitting
laser (VCSEL).
61. Apparatus, as claimed in claim 60, wherein said VCSEL is used
as at least part of said detector.
62. Apparatus, as claimed in claim 61, wherein said detector
comprises a substantially radially symmetric arrangement which is
substantially concentric with said laser light source.
63. Apparatus, as claimed in claim 61, wherein said detector is
laterally spaced a first distance from said laser light source.
64. Apparatus, as claimed in claim 63, further comprising a
birefringent material sized and shaped to laterally offset a
reflected beam from said laser light source by said first
distance.
65. Apparatus, as claimed in claim 63, wherein said first distance
is less than or equal to about 0.05 mm.
66. Apparatus, as claimed in claim 61, wherein said apparatus
occupies a volume defining a form factor of less than or equal to
about 60 mm in width, less than or equal to about 12 mm in height
and less than or equal to about 50 mm in depth.
67. Apparatus, as claimed in claim 61, wherein said storage medium
is a rotatable disk.
68. Apparatus, as claimed in claim 67, configured to facilitate
end-user removal and replacement of said disk.
69. Apparatus as claimed in claim 67, wherein said rotatable disk
is at least partially covered by a cartridge.
70. Apparatus as claimed in claim 69, configured to facilitate
end-user removal and replacement of said cartridge and disk.
71. Apparatus, as claimed in claim 61, wherein said detector
provides a data signal.
72. Apparatus, as claimed in claim 61, wherein said detector
provides a focus error signal.
73. Apparatus, as claimed in claim 61, wherein said detector
provides a tracking error signal.
74. Apparatus, as claimed in claim 61, wherein said detector is a
phi-detector.
75. Apparatus for optical data storage comprising: a rotatable,
user-removable disk; a drive, couplable to said disk, for rotating
said disk about a first axis; an optics arm having at least a laser
source, a detector, an objective and a focus actuator, and defining
an objective end and a second end; a tracking actuator, coupled to
said arm to controllably rotate said arm about a second axis,
substantially parallel to, but spaced from said first axis, to
position said objective end at desired radial locations adjacent
said disk.
76. Apparatus as claimed in claim 75 wherein the location and mass
of components of said arm are such that said rotation about said
second axis imparts a moment of inertia of less than or equal to
about 5 gm-cm.sup.2.
77. Apparatus as claimed in claim 75 wherein the location and mass
of components of said arm are such that said rotation about said
second axis imparts a moment of inertia of less than or equal to
about 1 gm-cm.sup.2.
78. Apparatus as claimed in claim 75 further comprising a
prism.
79. Apparatus, as claimed in claim 78, wherein said focus actuator
adjusts the distance of said detector from said prism.
80. Apparatus, as claimed in claim 75, wherein said focus actuator
adjusts the distance of said objective end from said disk.
81. Apparatus, as claimed in claim 75, wherein said focus actuator
comprises a piezo-motor.
82. Apparatus, as claimed in claim 75, wherein said laser source,
detector and objective are all positioned with respect to said
optics arm on the same side of said second axis.
83. Apparatus, as claimed in claim 82, wherein said laser source,
detector and objective are all positioned substantially adjacent
said objective end of said optics arm.
84. Apparatus, as claimed in claim 75 wherein each of said laser
source and objective defines an optical axis and wherein the
optical axes of said laser source and objective are coaxial.
85. Apparatus for optical data storage comprising: a rotatable,
user-removable disk; a drive, couplable to said disk, for rotating
said disk about a first axis; an optics system having at least a
laser source, a detector, and an objective; a focus actuator for
moving at least a portion of said optics system for adjusting focus
of light from said laser source on said disk, wherein said moving
is performed while maintaining at least said laser source and said
objective in a fixed spatial relationship with respect to one
another.
86. Apparatus, as claimed in claim 85, wherein a distance, along an
optical path from said laser source to said objective, remains
substantially constant during said moving for adjusting focus.
87. Apparatus for optical data storage comprising: a user-removable
disk, rotatable about a first axis, to define a disk plane; a
drive, couplable to said disk, for rotating said disk about a first
axis; an optics arm having at least a laser source, a detector, and
an objective; a focus actuator for controllably pivoting said
optical arm about an axis substantially parallel to said disk plane
for adjusting focus of light from said laser source on said
disk.
88. Apparatus for optical data storage comprising: a user-removable
disk, rotatable about a first axis, to define a disk plane; a
drive, couplable to said disk, for rotating said disk about a first
axis; an optics arm having at least a laser source, a detector, and
an objective; a focus actuator for controllably translating said
optical arm in a direction substantially parallel to said first
axis for adjusting focus of light from said laser source on said
disk.
89. A user-removable optical data disk, said disk having a diameter
less than or equal to about 35 mm.
90. A disk, as claimed in claim 89, wherein said disk is at least
partially hard-formatted.
91. A disk, as claimed in claim 89, wherein said disk is at least
partially pre-recorded.
92. A user-removable cartridge for housing an optical data disk,
said cartridge having a thickness less than or equal to about 3 mm
a width less than or equal to about 40 mm and a depth less than or
equal to about 40 mm.
93. A cartridge, as claimed in claim 92, wherein said disk is at
least partially hard-formatted.
94. A cartridge, as claimed in claim 92, wherein said disk is at
least partially pre-recorded.
95. A drive for reading or writing data from or to an optical data
recording disk, said drive having a thickness less than or equal to
about 12 mm, a width less than or equal to about 55 mm and a depth
less than or equal to about 40 mm.
96. A user-removable optical data recording cartridge comprising: a
first-surface optical recording medium having at least a first
optically recordable and readable surface; a cartridge body, with
said medium positioned therein, so as to permit rotation of said
medium in said cartridge body.
97. A user-removable optical data recording cartridge comprising: a
first-surface optical medium having at least a first optically
readable surface; a cartridge body, with said medium positioned
therein, so as to permit rotation of said medium in said cartridge
body.
98. A user-removable optical data recording disk comprising: a
first-surface optical medium having at least a first optically
readable surface having at least first data or servo features
embossed therein.
Description
[0001] The present invention relates to a removable optical storage
medium and in particular to an optical storage disk cartridge.
BACKGROUND INFORMATION
[0002] 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. Common current
(typically read-only) examples include the compact disk (CD) and
digital versatile disk (DVD). Although these examples have been
highly successful for particular applications, such as storing data
for use on a personal computer (PC), or storing music or other
audio or video information, such as motion pictures, these devices
have proved less useful in situations where, for practical,
historical or other reasons, an optical storage medium with a
smaller size is preferable. One class of such application includes
various personal electronic devices (PEDs). Personal electronic
devices in general have a size, shape and weight such that it is
feasible and convenient to carry or wear such devices on the
person. Typically, to be practical, such devices need to be
substantially pocket-sized (e.g. no more that about 100 mm,
preferably no more than about 50 mm in the longest dimension, and
preferably having at least one cross section no more than about 100
mm by about 50 mm, preferably no more than about 75 mm by about 35
mm) and/or a mass of about 12 oz (about 1/3 kg) or less. Examples
of personal electronic devices include music reproduction equipment
such as small tape players with headphones or MP3 players, cellular
telephones, dictating equipment, digital cameras, at least some
types of small computers, known as personal digital assistants
(PDAs), and the like.
[0003] Owing, at least in part to the great popularity of personal
electronic devices, and to the fact that certain personal
electronic devices store (and/or utilize pre-stored) data there is
a need for a data storage system and/or medium which is compatible
with at least the size and weight constraints of personal
electronic devices. Various types of storage systems have been used
or proposed for some or all kinds of personal electronic devices,
but have proved to be less than ideal for certain applications,
e.g. in terms of storage capacity, size, power consumption, cost,
and/or convenience.
[0004] One type of personal electronic device for which there is a
continuing need for a practical data storage system is the digital
camera (although the data storage system and medium of the present
invention is also usable in many types of electronic devices,
including, but not limited to, many types of personal electronic
devices). Typically, users of digital (still) cameras prefer
digital cameras which have a size, shape and weight which are not
significantly greater than the size, shape and weight of
conventional film cameras and accordingly, most digital cameras are
too small to accommodate, for example, a CD-R (recordable compact
disk) and/or DVD-sized optical media (having a diameter of 12 cm).
Instead, typical digital cameras provide storage, within the
camera, on storage media which are typically non-optical, such as
on so-called flash memory or other electronic memory. Flash
memories are non-archival in the sense that, in the absence of
refreshing, the memory contents will degrade. As used herein,
archival memory relates to memory which, without refresh or similar
operations, is substantially free from data loss over an extended
period, such as ten years or more. Although many flash memories are
designed to be removable (i.e. removable by the typical end user
during normal use), in view of the high expense of flash memory and
in view of the relatively limited capacity of such flash memory or
similar storage, some digital cameras are configured to accommodate
downloading image data, from the flash or other electronic memory
in the camera, to another storage device such as the hard drive of
a personal computer, e.g. via a cable temporarily coupled between
the camera and the personal computer. To store new images on the
flash memory, flash memory is then refreshed, with loss of
previously-stored images. Flash memory is re-writeable (i.e. is not
a write-once medium) and its high cost makes it generally
impractical to use flash memory as the medium to both capture and
store (or archive) images (in a manner analogous to photographic
film). Typically, once the on-board flash or other memory of a
camera has been filled with image data, the photographer will
either download some or all portions of the stored data (thus
requiring ready access to, e.g., a personal computer, or other data
storage device) or erase some or all of the stored images,
typically in an irretrievable fashion. It is believed generally
undesirable to provide a system in which image data can (and/or, in
practice, must) be erased, since this creates the potential for
accidently erasing images which were intended to be kept, and
further requires taking active steps, such as downloading data to
another medium, in order to retain or archive images. Accordingly,
it would be advantageous to provide a system and storage medium
usable in a digital camera in which images are stored in a
substantially non-erasable fashion.
[0005] Furthermore, such a configuration for a digital camera
departs significantly from the film camera paradigm, to which many
photographers are accustomed, in which exposed film may be readily
replaced with fresh film and in which developed "negatives" can be
stored in a compact space, without the need for use of a separate
apparatus such as a computer and without the need for performing
two or more subsequent download operations, such as, in the case of
a digital camera, from the camera to a PC and from the PC to a
diskette or other removable storage medium.
[0006] The amount of data needed to store an image will vary
depending, e.g. on factors such as image size, resolution (pixel
density), color depth and the like. Currently, it is not uncommon
for each image to represent about 6 megabytes of data which may be
compressed (e.g. using MPEG2 compression) to about 1 megabyte of
stored data. It is anticipated that consumer preferences for
higher-quality images may drive this figure upward. A relatively
large number of images are also involved in storing so-called
video-still clips. Typically these require storing a video clip ten
to thirty seconds in length, with images being taken at the rate of
five to ten frames per second. Although it may be possible to
provide a digital camera with a removable magnetic medium such as a
magnetic diskette, such diskettes typically have severely limited
capacity often providing storage for only a few, in some cases only
about one, image. It is believed that a practical digital camera,
especially in light of the film camera paradigm, to which many
photographers are accustomed, will have the ability to store at
least about twenty images, preferably at least about three dozen
images, and possibly many more, on each removable medium unit.
Accordingly, it would be advantageous to provide a system and
storage medium usable in a digital camera which can store
approximately twelve or more digital images, each image requiring
about one megabyte or more of (possibly compressed) data.
[0007] In some systems, including magnetic recording systems,
optical recording systems, and others, an attempt is made to
achieve high data capacity by placing the read/write head (or
objective) nearly in contact with the disk, such as less than about
0.025 to 0.05 micrometers. In these systems, sometimes referred to
as solid immersion or evanescent systems, such close proximity of
the read/write head to the disk typically requires an ultra-clean
environment, since even sparse and/or very small particles or other
contaminants can cause a potentially disastrous head crash, and in
general it is believe such systems are inappropriate for
removable-media applications. Accordingly, it would be advantageous
to provide a system that can achieve high data density (such as
about 0.25 Gbytes or more per recording surface on a 35 mm diameter
or smaller disk) while maintaining a spacing between the read/write
head or objective and the disk of at least about 50
micrometers.
[0008] Moreover, data transfer rates to magnetic storage media of
the types used directly in digital cameras, such as floppy disks,
are relatively low (so that the amount of time required to store
data on magnetic media in a digital camera can be unacceptably
long) and the rate of power consumption can be relatively high,
leading to relatively short effective battery or charge lifetimes.
Accordingly, it would be advantageous to provide a system and
storage medium usable in a digital camera with increased transfer
rates and/or decreased power consumption (e.g. compared to transfer
rates and power consumption of typical systems using so-called
floppy diskettes or other magnetic media).
[0009] Additionally, the cost, to the consumer, of electronic media
may be relatively high such as about $4.00 for each one megabyte
image, or more. Accordingly, it would be advantageous, particularly
in light of the film camera paradigm, to which many photographers
are accustomed, to provide a system and storage medium usable in a
digital camera in which the cost, to the consumer, per image is
reduced, e.g. compared to current electronic media used in
connection with digital cameras.
[0010] In addition to the storage medium being advantageously sized
for accommodation in a camera which is sized similarly to prior
film cameras (such as typical 35 mm film cameras), it is believed
also advantageous to provide a removable medium which is sized to
facilitate handling and storage by typical consumers. It is
believed that there is a practical lower limit on the size of such
media, e.g. since units which are too small will be susceptible to
being lost or misplaced and may be difficult for consumers to
handle, particularly those with limited movement or disabilities.
Thus, the removable media preferably are not substantially smaller
than items which are generally near the lower limit of what may
readily be handled, such as coins, stamps, and the like.
Accordingly, it would be advantageous to provide a removable
storage medium which is not significantly smaller, in width or
length, than about an inch (i.e. not significantly smaller than
about 25 mm). Additionally, the removable medium is advantageously
not so large that it becomes cumbersome to store or transport, and
preferably is sufficiently small that it can readily be held in a
typical shirt pocket. Accordingly it would be advantageous to
provide a removable storage medium which is not significantly
larger, in width or length than about 3 inches, preferably not
significantly larger than about 2 inches (about 50 mm). In
contrast, the standard CD or DVD disk is about 4-5/8 inches ( about
120 mm) in diameter, which is believed too large to be accommodated
in a pocket-sized camera or to be, itself, considered
pocket-sized.
[0011] Accordingly, it would be useful to provide a data recording
system which provides a removable medium, preferably non-erasable,
with a high-transfer rate, lower power consumption and large
capacity, but which is sized for effective and convenient consumer
use (e.g. with largest dimensions about 25-50 mm) and so as to be
accommodated in relatively compact digital cameras, such as digital
cameras with a size, shape and/or weight not substantially
exceeding that of corresponding film cameras.
[0012] Although relatively high data densities are desired,
particularly for use in relatively small-diameter disks, many
previous optical media are configured such that data densities are
effectively limited in the data density that can be provided.
Previous optical media typically provide an interior recording
layer (which, as described below, is often a composite layer, made
up of two or more thin films). Many common types of optical media
are second-surface media, i.e. media in which the read/write beam
traverses a relatively thick optically transparent layer before
reaching the (possibly composite) recording layer. FIG. 7A
illustrates one type of second-surface medium. In the illustration
of FIG. 7A, a composite (multi-film) recording layer 710 includes a
recordable dye or phase change film 712 (formed from any of a
number of known materials), typically adjacent one or more
dielectric films 714 (provided for thermal management, protection
from oxidation or other environmental attack, and the like),
coupled by an adhesion film 716 to one side of a transparent (at
the read/write beam wavelength) layer 718 (such as glass,
polycarbonate or other polymer). The interior 720 of the
transparent layer 718 is opposite to the operational surface 722
where the read/write beam 724 first arrives. In this context, phase
change refers to changes in the phase of the medium, such as
changes between crystalline and amorphous phases (e.g. as opposed
to electrical, optical or other waveform phase).
[0013] Many optical effects that are dealt with in the design of an
optical storage system vary with the wavelength of the light
involved, and accordingly, it is useful to discuss certain
distances or thickness in terms of the number of wavelengths of the
light being used for read/write operations. In the following, a
distinction is made between longer distances, greater than about 50
wavelengths of the light, and smaller distances, such as distances
less than about 50 wavelengths, or distances of about 10 or fewer
wavelengths. Embodiments of the present invention are described,
below, in connection with a system in which the wavelength of the
light involved is about 650 to about 800 nm, so that structures
with dimensions of about 130 micrometers or more are considered
longer distances . In a second-surface medium, the transparent
layer 718 is sufficiently thick (such as about 500 micrometers or
more), that read/write operations are relatively insensitive to
dust particles, scratches, and the like which are located more than
50 wavelengths from the recording layer (such that, considering the
cone angle, there is little effect on shape or power of the light
spot, by the time it reaches the recording layer), but can be
relatively sensitive to various optical aberrations, owing to the
fact that the read/write beam 724, after an aberration is created
at the air/transparent layer interface, must propagate through a
relatively longer distance (through the thickness of the relatively
thick trasparent layer 718) before reaching the recording layer
710, and must traverse the transparent layer 718 again after
reflection, e.g. from reflective film 726 (which may be coupled to
a lower, e.g. polymer, layer 728). Thus, the read/write beam 724
"sees" the transparent layer 718 before it arrives at the recording
layer 710. In this way, the recording layer 710 is the second layer
of the multi-layer medium 732 which the read/write beam reaches. In
addition to the increased sensitivity to aberrational effects that
arises from the relatively longer light propagation paths, many
aberrational effects are exacerbated by the cone angle and tilt
(non-perpendicularity of optical axis with respect to plane of
recording medium). As a result many previous optical systems have
used rail or similar linear guides for tracking, in order to avoid
substantial beam tilt.
[0014] In optical storage utilizing marks written by laser in some
recording material, storage capacity is limited by the minimum size
of mark that can be written. This is set in turn by the minimum
size of focal spot that can be generated by the laser and optical
system. The minimum theoretical spot size is determined by the
wavelength and numerical aperture or NA (i.e. cone angle) of the
focusing beam. However, in practice, the optical system is always
imperfect, e.g. due to manufacturing errors. For example, the final
focusing lens (the objective) may have an imperfect shape due to
polishing errors or, if injection molded, due to stresses in the
mold. These errors result in optical aberrations which increase the
spot size from ideal.
[0015] As noted above, in second-surface media, the presence of a
relatively thick transparent layer 718 or substrate exacerbates a
number of optical aberrations, including spherical aberrations (a
phase error causing rays at different radii from the optic axis to
be focused at different points), coma (creating a "tail" on the
recorded spot when the transparent layer 718 is not perpendicular
to the optical axis), astigmatism (creating foci along two
perpendicular lines, rather than a symmetric spot) and/or
birefringence (whereby different polarizations of light behave
differently). In second-surface recording, the disk substrate
itself (typically 0.6 mm or 1.2 mm of optical plastic) forms part
of the optical train. Therefore, the substrate's properties are
important, as well as the substrates's position relative to the
optical system, particularly its angle of tilt. Such errors have a
fractionally larger effect on spot size in systems where a larger
NA is provided in an attempt to increase storage density. These
errors have much greater effects on aberrations as the NA is
increased. Thus, a given mechanical tolerance such as disk tilt
will (in the absence of servo correction) place a limit on the NA
that can be used, and hence on the storage density. Thus, the
practical effect of the increase in aberrations resulting from
second-surface media is to limit the NA, in turn, effectively
limiting data spatial density.
[0016] Some or all of the aberrations arising form the presence of
the thick transparent layer 718 can, at least theoretically, be
partially compensated for by using lenses or similar optics,
although these may undesirably increase the cost or degrade the
performance of the system.
[0017] Moreover, such compensating lenses typically can only
provide such compensation for a single, pre-defined thickness of
the layer 718. Because there are likely be to spatial variations in
the thickness or other properties of the transparent layer 718,
such compensation may be less than desired at some locations of the
media.
[0018] Because the transparent layer 718 is typically formed from a
non-conductive material, there is a significant risk that rotation
or similar movement of the medium will create sufficient static
electrical charge that dust particles or other debris may be
attracted to (an/or become difficult to remove from) the
operational surface of the medium.
[0019] Despite these and other difficulties associated with
second-surface media, second-surface media are relatively
wide-spread, especially for systems in which the media are
unprotected by an enveloping cartridge or other device, at least in
part because the recording layer is effectively isolated from dust,
scratches and the like by the (relatively thick) transparent layer
718. Accordingly, it would be useful to provide a recordable medium
which can avoid some or all of the disadvantageous aspects of
second-surface media.
[0020] CDs, DVDs and similar optical storage media are typically
provided as a single disk-shaped device, without the need for a
cassette or other enveloping holder. The lack of an enveloping
holder or cassette, while practical in the context of current data
storage devices, music (or other audio) or motion picture (or other
video) storage devices, also presents certain drawbacks which may
be particularly acute for certain contemplated uses, such as
digital camera and/or small-format (such as to fit in a digital
camera) uses. Because CDs and DVDs are typically provided without a
cassette covering, to protect the recording medium, CDs and DVDs
are provided as second-surface media, i.e. one or more relatively
thick (such as about 0.6 mm) and optically transparent, layers
cover at least one surface of the CD-ROM or DVD. This protective
layer is sufficiently thick that it exacerbates certain aberrations
(and results in relatively high sensitivity to beam tilt) and thus,
in terms of the optics of the system, the data recording layer of a
CD or DVD is not the first surface of the disk which the read/write
beam reaches. The need to accommodate the optical effect of the
protective layer has consequences for the data density of a CD-ROM
or DVD. Effectively, the data density provided in the CD or DVD is
limited by the presence of a relatively thick protective layer. The
presence of the relatively thick protective layer is, in turn,
substantially dictated by the fact that the CD or DVD disk is
otherwise unprotected, i.e. is not enveloped in a cassette or other
covering. Rather, the relatively thick transparent layer 718 means
that scratches, dust particles and the like are spaced sufficiently
far from the recording layer that they are substantially defocused
and occupy only a small portion of the incoming beam. Current
optical storage devices such as DVD devices provide for storage of
about 4.75 Gbytes of data in about 9366 mm.sup.2 of surface. Since
the data density which can be achieved in optical storage medium
affects the physical size of the disk needed to achieve a given
data capacity, second-surface media such as used in a CD or DVD
would require quite close tolerance and high precision, and thus
high cost, in fabrication of both the disk and the drive in order
to provide high capacity, such as a capacity of 0.25 Gbytes or more
per recording layer (if it could be done at all), in a disk small
enough to be accommodated in a typical digital camera (such as a
diameter of less than about 50 mm, preferably less than 40 mm).
Accordingly, it would be useful to provide an optical data system
which can achieve relatively small disk sizes, such as a disk
diameter of about 50 mm or less, while achieving relatively high
data capacities, such as a capacity of 0.25 Gbytes or more per
side, preferably 0.5 Gbytes or more per side (e.g. in connection
with a short wavelength "blue" "laser"), at a relatively low cost,
such as a cost, to consumers of about five dollars or less per 250
megabytes of data storage capacity.
[0021] Much of the development of optical disk data storage has
centered around apparatus in which the read/write mechanism was
configured to position a read/write beam, at a desired radial
location on the disk in a substantially linear fashion (so-called
linear actuators). While linear actuators have proved useful in a
number of contexts such as for reading/writing, CDs and DVDs, the
location of the masses of components in such linear actuators has
typically been so as to affect performance parameters such as
access time, data transfer rates, and the like. These factors can,
in turn, have an effect on the price, for a given level of
performance, for such devices. In general linear actuators are
relatively high-friction devices and require precise track
alignment. Linear actuators typically add substantial thickness to
a read/write or drive device and generally do not scale well toward
miniaturization. Thus linear actuators have, in general, found
greatest use in applications where thickness, access time,
bandwidth and power consumption are of less importance, and
typically are used in situations where the moving read/write head
is relatively massive. Accordingly, it would be useful to provide a
optical data-storage medium and/or cartridge configured to
accommodate a non-linear, such as a rotary, actuator.
[0022] Although the size, shape and weight of removable media for a
digital camera can be of importance in the success of a digital
camera, the configuration of the removable media (and enveloping
cassette) is strongly tied to the configuration of the read/write
device (the "drive") including by such factors as rotation speed,
actuator speed, and path, insertion/removal devices or methods and
the like. Accordingly, it would be useful to provide a removable
optical storage medium (and/or enveloping cartridge) configured for
use in connection with a drive or read/write device which is,
preferably, relatively low in cost, small, and lightweight.
SUMMARY OF THE INVENTION
[0023] The present invention includes a recognition of the
existence and/or nature of certain problem in previous systems,
including those discussed herein. The present invention provides a
removable optical data recording cartridge which is configured to
have relatively high capacity and relatively low weight, size and
cost. In one aspect, the system includes writeable media and,
preferably, an optical disk cartridge is configured for use in
connection with a rotary actuator for data reading and writing. The
system can be used in a number of manners including as part of a
system for capturing and/or recording data (such as in a digital
camera, audio or video recorder, and the like), as part of a system
for playing or otherwise outputting data (such as displaying
recorded or "pre-recorded" images, video, audio or other
information) or combinations thereof. According to one feature of
the invention, the medium is a first-surface medium protected by an
enveloping cartridge. Preferably the medium can be configured for
recording on both surfaces and the cartridge is configured to
permit actuator access through either of two opposed cartridge
surfaces. The read/write surfaces of the disk are substantially
sealed when the disk is removed from the drive.
[0024] In one aspect of the invention, a user-removable optical
data storage cartridge is provided. The system can provide
relatively high data densities, including densities similar to
those found in DVD systems (about 2.6 Gbit per square inch of data
surface) as well as higher data densities such as about 4 Gbits per
square inch or more. The system provides relatively large data
capacity such as about 0.25 Gbytes or more despite a relatively
small size such as about 35 mm.times.35 mm.times.3 mm. In one
aspect, the medium is a first-surface medium. Preferably the
cartridge substantially seals the data surfaces of the medium when
the cartridge is withdrawn from a drive and at least a portion of
one surface is automatically exposed to the objective of an optics
arm when said cartridge is inserted in a drive.
BRIEF DESCRIPTION OF THE DRAWINGS
[0025] FIG. 1 is a perspective view of an optical recording
cartridge according to an embodiment of the present invention;
[0026] FIG. 2 is an exploded, bottom perspective view of a drive
useable in connection with the cartridge of FIG. 1, according to an
embodiment of the present invention;
[0027] FIG. 3 is an exploded top perspective view of the device of
FIG. 2, also depicting, in exploded fashion, the cartridge of FIG.
1;
[0028] FIG. 4 is a top plan view of a drive and inserted cassette,
with a top cover removed, according to an embodiment of the present
invention;
[0029] FIG. 5 is a cross-sectional view taken along line 5-5 of
FIG. 4;
[0030] FIG. 6 is a side-elevational view of an actuator arm usable
in connection with an embodiment of the present invention;
[0031] FIGS. 7A, 7B and 7C are cross sectional views through
illustrative configurations of second-surface and two embodiments
of first-surface media, respectively;
[0032] FIG. 8 is an exploded top perspective view of a cartridge
for use with hubbed media in connection with an embodiment of the
present invention;
[0033] FIG. 9 is an exploded bottom perspective view of a cartridge
with non-movable window covers according to an embodiment of the
present invention;
[0034] FIGS. 10A and 10B are exploded bottom and top, respectively,
perspective views of a cartridge for recording a single surface of
a recordable medium, according to an embodiment of the present
invention.
[0035] FIG. 11 is a block diagram of a main circuit board, usable
in connection with the drive of the present invention;
[0036] FIG. 12 is a top plan view of a layout for a circuit board
of FIG. 11, according to an embodiment of the present
invention;
[0037] FIG. 13 is a partial cross-sectional view through the
central portion of a disk and cartridge, according to an embodiment
of the present invention;
[0038] FIG. 14 is a partial cross-sectional view of a mechanism for
engaging a spin motor hub;
[0039] FIGS. 15a and b are side elevational views of an optical arm
latch in first and second positions, according to an embodiment of
the present invention;
[0040] FIGS. 15c and d are end elevational views of an optical arm
latch in positions corresponding to those depicted in FIGS. 15a and
b, respectively, according to an embodiment of the present
invention;
[0041] FIG. 16 is a partial perspective view of a cartridge
interior illustrating a shutter-movement mechanism, according to
one embodiment of the present invention;
[0042] FIGS. 17 and 18 are schematic, perspective, partially
exploded, and top plan views, respectively, of optical components
according to an embodiment of the present invention;
[0043] FIG. 19 is a top plan view of optical components according
to an embodiment of the present invention;
[0044] FIGS. 20A and 20B are side elevational and end elevational
views of an optical arm according to an embodiment of the present
invention;
[0045] FIGS. 21A and 21B are side elevational views of optical arms
and focus actuators, according to embodiments of the present
invention;
[0046] FIG. 22 is a bottom perspective, partially exploded, view of
a digital camera, according to an embodiment of the present
invention;
[0047] FIG. 23 is a side elevational view of an optical arm and
focus actuator according to an embodiment of the present
invention;
[0048] FIGS. 24A and B are partial side elevational and perspective
views of an optical arm according to an embodiment of the present
invention;
[0049] FIGS. 25A and B are partial side elevational and perspective
views of an optical arm according to an embodiment of the present
invention;
[0050] FIG. 26 is a schematic perspective view of an optics
configuration with coaxial detectors, according to an embodiment of
the present invention; and
[0051] FIG. 27 is a schematic, side elevational view, partly in
cross-section, depicting an optical arm with a linear focus system
according to an embodiment of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0052] As shown in FIG. 1, according to one embodiment, a
removable, recordable optical storage cartridge 112 includes a
rotatable writeable optical storage disk 114 surrounded by a
cartridge body having an upper wall 116 and a lower wall 118 joined
by a substantially rectangular side wall 122. In one embodiment,
the medium is an InSbSn phase change medium, of a type used by
Kodak, in connection with 14 inch optical write-once-read-many
(WORM) disk products. Examples of suitable media are described in
U.S. Pat. Nos. 4,960,680 and 5,271,978. Such a medium is suitable
as a first-surface medium. Such a medium is substantially
pan-chromatic or "broadband," such that it can be used with a range
of laser light frequencies (e.g. from 400 nm or less to 1100 nm or
more wavelength), making it possible to use the invention described
herein in connection with short-wavelength lasers (e.g. blue
lasers), to achieve a smaller spot size (and thus higher data
density) substantially without the need to modify the medium It is
anticipated that a disk 114 formed using such a medium will be
substantially rigid. Another example of a medium that can be used
in embodiments of the present invention is that described in U.S.
Pat. No. 4,816,841 of Kurary Plasmon Data Systems Co., Ltd., which
is an example of a medium with a plastic substrate. Non-rigid media
may, in some embodiments, be adhered to (or otherwise coupled to)
one or both surfaces of a rigid substrate to provide a rigid,
compound medium, or may be coupled to a semi-rigid substrate (to
provide a semi-rigid, compound medium) or left uncoupled to a
substrate to provide a non-rigid medium. As depicted in FIG. 8, if
the cartridge 112 is used in connection with a non-rigid or
semi-rigid film-type disk, 812, the disk 812 is preferably provided
with a separate hub 814 to define the center (e.g. for minimizing
run-out). The hub 814 can also be useful in providing a seal
between the central opening of the cartridge 816a, 816b and the
disk 812, e.g. to avoid contact with or contamination of the
data-bearing portions of the disk 812.
[0053] FIG. 13 depicts one manner of avoiding entry of dust
particles and the like into the interior of the cartridge via the
hub area. In the embodiment of FIG. 13, an annular labyrinthine
seal is formed between the hub region of the disk 114 and the
interior surfaces of adjacent regions of the upper 124 and lower
126 cartridge components. In the depicted embodiment annular
tongues 1312a, b, c, d extending inwardly from interior surfaces of
the upper 124 and lower 126 cartridge components interdigitate with
complementary annular grooves 1314a, b, c, d formed in the hub
region of the disk 114. Other labyrinth configurations can be used,
such as providing tongues on the disk and grooves in the cartridge,
providing maze-like lateral interdigitations and the like can also
be used. Without wishing to be bound by any theory, it is believed
that labyrinths can be constructed to provide an effective path
which is sufficiently long and contorted that it is statistically
unlikely that a particle, of a size commensurate with or larger
than the objective-to-medium distance, can penetrate the seal, e.g.
considering factors such as the mean free path for the expected
size/mass of particles, expected air flow patterns and the like. If
desired, the shutter system 144a,b can be configured to cover the
central opening 816a, b when the cartridge 112 is removed from the
drive to further or alternatively protect against entry of
particles via the central opening. Preferably, the objective is
spaced at least about 50 micrometers from the operative surface of
the disk.
[0054] Preferably, the medium is configured as a first-surface
medium. In a first-surface medium, such as depicted in FIG. 7B, the
(possibly composite) recording layer 740 is the first layer reached
by the read-write beam. The recording layer "stack" 740 is thin
compared to the substrate on which they are deposited. The stack
thickness is typically only <1 .mu.m to 10's of .mu.m thick,
compared to a substrate thickness typically in the range 300-1200
.mu.m.
[0055] As illustrated in FIG. 7C, in one embodiment, a recording
film 742 may define an outermost surface of the disk, such as when
the disk is formed by placing a recording film directly on a
substrate 752, so that the read/write beam does not pass through
any portion of the disk prior to reaching the recording film 742.
In the depicted embodiment, the recording layer is made up of the
single film 742. If desired, a thin coating (such as a few
molecules thick) of carbon or other wear-resistant material (not
shown) can be deposited on the exterior surface of the film 742.
The configuration of FIG. 7C may be feasible, e.g. when the
material of the film 742 has sufficient adhesion to the substrate
752, and/or has acceptable thermal characteristics and the like. In
other embodiments, it may be desired to provide a recording layer
which has additional films, such as depicted in FIG. 7B.
[0056] In the embodiment of FIG. 7B, the read-write beam traverses
film 744a of the multi-film, composite recording layer 740 before
reaching the recordable dye or phase change film 742. In other
embodiments, the beam may traverse two or more films before
reaching the recordable film 742. Preferably, films which are
traversed before reaching the recordable film 742 are sufficiently
thin, such as equal to less than about two wavelengths (e.g. 100 nm
or less, preferably less than about 50 nm, for 650-800 nm light),
that aberrations (e.g. of the type discussed above in connection
with the thick transparent layer 718 of the second-surface medium)
arising from or exacerbated by the presence of the film 744a are
sufficiently small that there is little need to consider such
aberrations when designing the read-write beam path. In this sense,
the recording layer 740 is effectively the "first surface" reached
by the read-write beam. Because the film 744a through which the
beam 754 must pass before reaching the recordable film 742 is
relatively thin, the first-surface medium of the present invention,
including that illustrated in FIG. 7B, avoids or reduces the
optical aberrations and other disadvantageous aspects of
second-surface optical data storage media, including those that
were described above, such as spherical aberrations, coma,
astigmatism and/or birefringence. Since, as described above, the
effect of errors such as disk tilt depends on the substrate
thickness, first-surface recording can significantly reduce the
effect of these errors and allow the NA and density to be
increased. Further, there is relatively less power loss in the
first-surface system of FIG. 7B (compared, e.g. to a second-surface
system such as that described above in connection with FIG. 7A.).
The dielectric film 744a is sufficiently thin that there is little
effect on beam focus. As a result, it is possible to achieve
relatively small spot size (and thus relatively high areal data
density), at a reasonable cost.
[0057] The ability to achieve a relatively large data capacity on a
small disk is also advantageous in that the relatively small
(rotational) moment of inertia of a small disk means that the power
consumption of the device is lowered. The power required to
accelerate the disk to the desired spin velocity (in a desirably
short spin-up time), or to decelerate the disk, if needed, e.g. to
provide a desired speed at a given radial location, is lower for a
smaller and less massive disk.
[0058] Although many configurations of first-surface media can be
used in the context of the present invention, FIG. 7B provides an
example of one configuration. In the illustration of FIG. 7B, a
(multi-film) recording layer 740 includes a recordable dye or phase
change film 742 sandwiched between two dielectric films 744a, b. A
reflective film 746, adjacent the sandwich 744a, 742, 744b, is
coupled by an adhesion film 748 to a substrate 752. In the
illustration of FIG. 7B, the upper surface of the upper dielectric
film 744 defines the operational surface of the recording layer
740, i.e. is initially struck by the read/write beam 754. If
desired, a thin coating (such as a few molecules thick) of carbon
or other wear-resistant material (not shown) can be deposited on
the operational surface of the medium.
[0059] Preferably, the films making up the recording layer 740
(such as films 742, 744a, 744b, 746 and 748, in the illustration of
FIG. 7B) are relatively thin, such as less than about 100 nm each,
preferably less than about 50 nm. The recording layer 740 is less
than about 1000 nm thick, preferably less than about 400 nm, and
may be as thin as about 20 nm or less.
[0060] The recordable medium film 742 can be formed of a number of
materials. In various embodiments, the recording film is preferably
thermally-written and optically-read and may be write-once, such as
a phase-change material, (for example, TeO or a chalcogenide alloy,
e.g., InSbSn) or a dye (for example cyanine or pthalocyanine dye)
or it may be erasable and re-recordable, such as other phase change
materials (GeTeSb) or magneto-optical. It is also possible to use
an optically written medium. A number of optically-written
materials are known, a common example being photographic film. In
at least one embodiment, the recordable medium film 742 is
substantially electrically conductive, so that static charges will
tend to be dissipated, rather than contributing to unacceptable
build-up of dust particles or other debris. Preferably, reading of
information recorded in the recording layer is done reflectively,
i.e. the light signal reflected from the stack is monitored and
used for all signals, such as servo feedback and power adjustment,
as well as for readout of the data. The thickness of the recordable
medium film 742 is selected depending on a number of factors such
as absorptivity, transparency, thermal properties and the like.
[0061] In one embodiment, the recording film 742 is deposited
directly on the substrate 752, and there need be no other films or
layers, if it is sufficiently chemically resistant to be exposed to
air and moisture. The recording film (such as InSbSn or GeTeSb) may
be deposited by sputtering, evaporation or other means. The
material composition, substrate and deposition parameters may be
chosen for optimal adhesion and layer quality. Thickness may be
optimized to make use of optical interference between the incident
surface and the film/substrate boundary to improve coupling of the
write beam (improve sensitivity) and/or enhance the reflectivity
contrast in readout.
[0062] The dielectric films 744a,b, if present, can be formed from
a number of materials, including co-deposited ZnS--SiO. A
dielectric film may be added on one or both sides of the recording
film 742 . In the case of a top film 744a (i.e. between recording
film and air) it can provide chemical and moisture protection, as
well as hardness for scratch resistance. Also it can provide
thermal insulation to reduce convective cooling from the recording
film in a spinning disk which would otherwise reduce sensitivity. A
top film can also provide an optical anti-reflection function by
choosing the film's refractive index and thickness. In general,
dielectric films are useful for any or all of a number of purposes,
including:
[0063] controlling or compensating for differences in inter-film or
inter-layer thermal properties or other thermal management
purposes, such as thermal expansion coefficients, thermal
capacities, thermal conductivities and the like,
[0064] enhancing contrast e.g. between light reflection and
absorption or scattering (i.e if the dielectric is provided with a
thickness such that it acts as a quarter-wave plate) and/or optical
"tuning,"
[0065] reducing or preventing diffusion, transport or migration of
moisture, gases or chemicals from other films or layers or from the
environment, and the like, including avoiding contact of dust or
aerosol particles or the like with interior films e.g. 742;
[0066] containing material that is boiled or melted in the case of
erasable phase change or dye media.
[0067] In a structure with dielectric films, a metallic reflective
film 746 may be added. This is particularly advantageous with dye
media, since it is predominantly only the absorption of the media
that is changed, and the reflection signal can be enhanced by using
a reflector film and a double pass of the beam. The reflective
film(s) 746 can be formed from a number of materials, such as
aluminum or other metals. Metallic reflection films are generally
good thermal conductors, and may be used in part to manage heat
flow. This is particularly useful with erasable phase-change media
where rapid cooling rates are desired for writing bits. Note that
with first-surface recording, the substrate itself may be metallic
and may act as a reflector.
[0068] The adhesion films(s) 748 may be provided between films or
layers which would have poor adhesion if placed in direct contact.
An adhesion film 748 between the recording film and substrate 752
provides for potentially improved adhesion to the substrate, as
well as modifying the properties of the recording film when it is
deposited, such as it's crystallite size in the case of a
phase-change medium, which can lead to improved sensitivity and
recording uniformity. In addition, the adhesion film can provide
optical advantages, such as modifying the readout contrast. In
addition, it can be part of the thermal optimization. For example,
if the media is erasable phase-change, then it is desirable to
control the rate of heat flow to the substrate or other layers. The
adhesion film(s) may be as thin as 2-5 angstroms.
[0069] The substrate 752 may be plastic, either transparent or
absorbing, such as polycarbonate or PMMA, or may be glass or
optical crystal, metal, fiberglass or other material. A feature of
first-surface reflective recording is that the optical properties
of the substrate are much more relaxed. In general, any transparent
or absorptive substrate may be used. The substrate may be planar
(for soft-formatting) or pre-grooved, such as in DVDs. Thickness
need only be sufficient to maintain mechanical tolerances such as
warp.
[0070] Although the dielectric film 744a can be useful in, among
other functions, reducing or avoiding, e.g., scratching or abrasion
problems arising from dust or other particles, there could be a
risk of data loss if the first-surface medium were not protected
from contact and/or contamination (including data loss resulting
from the optical or mechanical interaction of particles on or near
the operational surface of the medium with the optical arm and/or
read/write beam). This risk is especially great in a first-surface
medium, since a first-surface medium does not provide a relatively
thick protective layer such as the transparent layer 718
illustrated in the second-surface medium of FIG. 7A. In the
embodiment illustrated in FIG. 1, protection from such data loss is
substantially provided by the walls of the cartridge 112.
[0071] The cartridge body is preferably made by injection molding
of a thermoplastic material, although 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. Preferably the cartridge body is formed
by joining upper half 124 (FIG. 3) to a lower half 126 along a seam
line 128 such as by ultrasonic welding, adhesion, tab and slot
arrangements and the like. Although the embodiment of FIG. 1
depicts finger grip ridges 132a,b, these may be eliminated, for
example, if the drive is provided with a positive cartridge
ejection mechanism (not shown).
[0072] In the depicted embodiment, the leading edge 134 of the
cartridge 112 (i.e., the edge which is typically first inserted
into the drive area) includes camming/centering angled faces 136a,b
and may be provided with one or more recesses 138a,b,c,d,e,f which
may be used, as desired, to encode, by their number, position,
shape, depth or the like, characteristics of the cartridge 112 or
disk 114 such as data density, number of recordable sides,
formatting and the like. The recesses may be read, e.g. by one or
more fingers (not shown) positioned in the drive as will be clear
to those of skill in the art after understanding the present
disclosure. If desired a flat and/or recessed region 143 may be
provided to accommodate labels. A window 142 is formed in the upper
surface 116 extending substantially therethrough and aligned with
at least a portion of an upper surface of the disk 114.
[0073] In the embodiment of FIG. 9, a greater measure of protection
of the recordable surfaces of the disk 912 is provided by covering
the windows 942, 946 with (non-movable) covers 914a, 914b of
material which is transparent (at least at the wavelength of the
read/write beam). Examples of cover materials include, glass and
polycarbonate.
[0074] In the embodiment depicted in FIG. 3, the windows 142, 146
may be closed and/or sealed by a shutters 144a, b, pivoting about
shutter pins e.g. 155, engaging shutter holes 157a, b. In the
embodiment of FIG. 3, shutter 144a is moveable between the closed,
preferably sealing, position, and an open position to permit
access, through the window 142, to a recording surface of the disk
114. Preferably the cartridge 112 is configured to cooperate with
the drive, e.g. as described below, such that the shutter 144a is
automatically moved to the open position when the cartridge 112 is
inserted in the drive and is automatically moved to the closed
and/or sealing position when the cartridge 112 is removed from the
drive.
[0075] Preferably the cartridge 112 can be configured to
accommodate recording on both major surfaces of the disk 114. In
one embodiment, the drive is provided with an arm for recording on
one surface (such as the lower surface) at a time. To record on the
opposite surface, the user would remove cartridge 112, rotate the
cartridge to position the opposite surface lowermost and reinsert.
In such a configuration, the cartridge 112 is preferably configured
with a window 146 positioned on the second surface 118. Preferably
the second window 146 is located such that, following rotation to
place the second surface of the recording medium lowermost as
described above, the second window 146 will be located in a
position (with respect to the drive) substantially identical, to
the location of the first window 142 when the second surface is
uppermost. In this way, the actuator arm can be in the same
position range, regardless of whether surface 116 or surface 118 is
uppermost.
[0076] In another embodiment, as depicted in FIGS. 10A and 10B, the
cartridge can be configured to provide for recording on only one
surface 1012 of the disk 1014. In the embodiment of FIGS. 10A and
10B, although the cartridge contains first and second sides
1016a,b, only the side which is adjacent the surface of the disk
1012 that is to be recorded, is provided with a window 1046 and
shutter 1044b. Preferably, the cartridge is shaped (or has detent
1018 positions or is otherwise configured) to prevent inserting the
cartridge in an attitude other than with the window 1046 accessible
to the drive optics.
[0077] In one embodiment, at least one, and preferably both, side
edges (edges perpendicular to the leading edge 134) are provided
with one or more grooves 148 for engaging one or more guide rails
312 of a drive (FIG. 3) to assist in desired alignment or
positioning of the cartridge 112 with respect to the drive. In the
embodiment of FIG. 16, a moveable actuating pin 1612, extending
through a slot 1614 in the cartridge wall, is pushed in a direction
1616 toward the cartridge interior as the cartridge 112 is
positioned in the drive. As the actuating pin 1612 moves, it
engages a camming surface 154 of the shutter 144b covering the
lower window 146. In this way, as the cartridge 112 is inserted
into the drive, movement of the actuating pin 1612 engages the
camming surface 154 so as to move the shutter 144b, against the
urging of, e.g. a spring 1618, from a position covering the second
window 146 to a position 158 uncovering the window 146 (e.g. for
read/write access to the disk 114). Preferably, a similar mechanism
coupled to the upper shutter 144a automatically opens the upper
shutter 144a when the cartridge 112 is inserted in the drive in an
opposite orientation.
[0078] In one embodiment, the drive provides for rotary movement of
an optical arm and accordingly, in the illustration of FIG. 1, the
window 142 has a substantially arcuate shape defining a radius of
curvature of the window midline 162 substantially equal to the
effective radius 612 of the optical arm (the distance from the arm
rotation axis 614 (FIG. 6) to the midline of objective end 616 of
the arm). In one embodiment, the radius of curvature of the window
midline 162 is about 20 mm. The window 142 has a length (measured
along the midline 162) sufficient to provide access to the entire
radial extent of the read/write surface of the disk 144. In one
embodiment, the longitudinal extent 166 is about 9 mm. Preferably
the window 142 has a transverse extent 168 sufficient to permit at
least optical access of the beam and, preferably to permit
protrusion of the axial extent 618 objective end of the actuator
arm at least partially through the window 142. However, it is
preferred that the transverse extent of the slot 168 and the size
and shape of the objective end 246 of the actuator arm be selected
to provide a positive stop, preventing the objective end 246 of the
actuator arm from extending so far through the window 142 that the
objective end 246 of the actuator arm could contact the disk 114.
In one embodiment, the actuator arm may be provided with one or
more flanges (not shown) to limit the amount of protrusion into or
through the window 142. In one embodiment, the transverse extent
162 of the window 142 is at least about 2 mm.
[0079] In one embodiment, the cartridge 112 has a width 172 and a
depth 174 of less than about 40 mm, preferably less than about 35
mm. In one embodiment, the cartridge 112 has a thickness 176 of
less than about 5 mm, preferably about 3 mm. In one embodiment, the
inside diameter 178 of the disk 114 is less than about 7 mm,
preferably about 5 mm. In one embodiment the thickness 182 of the
disk 114 is less than 1 mm, preferably about 0.6 mm. In one
embodiment, the mass of the cartridge is less than about 7 gm,
preferably less than about 5 gm. In one embodiment the diameter 184
of the disk is between about 30 mm and about 35 mm, preferably
about 32 mm.
[0080] As shown in FIGS. 2 and 3, a drive can be provided for use
in connection with the cartridge 112 of FIG. 1. The drive includes
a housing 212 coupled to an upper cover 216 and baseplate 214. The
housing and covers can be made from a number of materials. Die-cast
metal is useful for providing structural stability and matching
thermal characteristics, but other materials can be used such as
plastic fiberglass and the like. A spin motor 218 includes a hub
222 configured to engage the central opening 179 of the disk 114.
In one embodiment, the spin motor provides a rotation rate between
about 1500 RPM (e.g. for reading/writing near the outside diameter
of the data area of the disk) and about 5000 RPM (e.g. for
reading/writing near the inside diameter of the data area of the
disk). A data transfer rate of about 1 MB per second, or more is
preferably achieved. The spin motor 218 is preferably relatively
efficient. In one embodiment, the drive as a whole operates on a
voltage of about 3.3 Volts.
[0081] The motor 218 can be positioned so the hub 222 extends
through an opening 223 of a housing 212 which will be aligned with
a central opening 179 of the cartridge 112 when the cartridge is
inserted in the cartridge receiving area 252 of the housing 212.
FIG. 14 depicts one operable configuration for engaging the motor
hub 222 with the central opening 179 of a disk 112. In the
embodiment of FIG. 14, a spin motor 218 with a splined shaft is
coupled (pivotally, about axis 1414) via trunnion 1416 to a
cartridge sense arm 1412. The cartridge sense arm mounted to permit
pivoting about arm pivot axis 1418, and is urged toward the
depicted retracted position by a retraction spring 1422. In use, a
cartridge 112 is inserted into the drive 514, e.g along a cartridge
mounting surface 1424 until the disk opening 179 is aligned with
the splined hug 222. In the depicted embodiment the hub 222 is
provided with spring fingers 1426. As the cartridge 112 approaches
this position, its edge engages a camming surface 1428 of the sense
arm 1412 forcing the free end down (in the view of FIG. 14) 1432,
against the urging of spring 1422, and causing pivoting about arm
pivot axis 1418 so as to raise the hub 222 into engagement with the
disk opening 179. In another embodiment, engagement can be effected
by pivoting a baseplate of the drive, to which the hub (as well as,
preferably, the spin motor, the optical arm and the like) is
coupled, to carry the hub into engagement with the opening 179.
Other manners of effecting engagement are possible such as pivoting
or otherwise moving the cartridge toward the hub, providing a
telescoping hub, and the like, as will be clear to those of skill
in the art after understanding the present disclosure.
[0082] The spin motor 218 is coupled by a flex circuit 224 to a
printed circuit board. In one embodiment, the circuit board 226 has
a cutout 227 to accommodate the spin motor 218, which protrudes
therethrough, for reducing the overall drive thickness. The printed
circuit board is provided with a coupling 228, e.g. with pin or
zero-insertion-force sockets 232 receiving, e.g., a flex circuit,
for communicating signals to the remaining portions of the digital
camera or other apparatus (not shown). Although the coupler 228 has
been depicted in a generic fashion, in one embodiment, the
interface (e.g. the native drive controller interface) between the
drive and the camera (or other electronic device) is by a universal
serial bus (USB) interface, and preferably the coupling 228
accommodates a USB connection, as well as other connections to the
digital camera (or other electronic device) such a power and ground
lines, and the like. In this regard a native drive controller
interface is on the drive itself. Although a USB interface provides
slower transfer rates than some other types of interfaces, and is
generally not used as an interface for a data storage device, it
supports transfer rates sufficient for, e.g., digital camera
applications, and is relatively inexpensive and non-complex to
implement, compared to the types of interfaces more commonly used
for data storage devices (such as SCSI, PCMCIA card interfaces, and
the like). In one embodiment, there is also a provision for using a
USB interface to download image data from the digital camera to a
PC or other computer. Preferably, the download process can involve
downloading the USB driver from the camera to the computer (e.g. if
the computer does not already have an appropriate driver),
preferably in a fashion that is substantially transparent to the
user.
[0083] In general, the main circuit board 226 includes control
electronics, power supplies, and interface logic. The components
shown in the block diagram of FIG. 11 can generally be considered
as being optical head electronics 1112 or drive electronics 1114.
Components of the Optical head electronics 1112, such as the laser
modulator, photodetectors, and analog-to-digital (A/D) and digital
to analog (D/A) converters are preferably located relatively close
to the optical arm, preferably in the electro-optic housing 237.
The optical head electronics substantially involve analog signals,
which are preferably converted to digital signals before
transmission to other components. Signals 1118a,b are communicated,
e.g. via the flex circuit 234, between the optical head electronics
1112 and a Channel integrated circuit (IC) 1122. The channel IC
1122 also communicates with a microprocessor 1124, via a processor
interface 1126. The microprocessor 1124 executes programs, e.g.
stored in a read-only memory (ROM) 1125. Digital signals 1128 are
communicated between the processor 1124 and the optical head
electronics. The channel IC provides read and write channels,
preferably with error correction code (ECC) circuitry 1134, such as
ECC circuitry of the type used in DVDs. The channel IC 1122
provides servo control 1136 to power drivers 1138 which power the
spin motor 1142 and track position motor 1144. The USB interface
1146 communicates, via a USB data input/output connector 1148 to a
host USB interface (not shown), e.g. in the digital camera. The USB
interface 1146 uses a dynamic random access memory (DRAM) as a data
buffer 1152, via a buffer controller 1154.
[0084] In the embodiment of FIG. 12, the region adjacent the edge
1212 of the PCB 226 containing the connector for coupling to an
optical arm 236 (specifically coupling signals for the laser, the
arm actuator and the focus actuator) contains the laser driver 1214
component, assisting in maintaining a relatively short signal path
for high-frequency signals. In one embodiment a flex circuit 234 is
used to couple the printed circuit board 226 to the optical arm
236. The optical arm is preferably low mass, but has high
stiffness, e.g. sufficient stiffness to reduce the amount of
mechanical resonance which could interfere with proper tracking. In
one embodiment the arm is formed from or includes titanium or
steel. An electro-optic housing 237 contains sensor electronics,
photo-detector(s) and servo-detector(s), of configurations that
will be understood by those of skill in the art after understanding
the present disclosure. The optical arm 236 is configured to pivot
around a pivot axis 266 through the center of pivot post 239
received in a post receiving area 242 of an actuator body 244
pivotally mounted to the baseplate 214 by post 245. The actuator
body 244 is configured to provide controllable rotation of the arm
236 about a vertical axis 256 for positioning the objective end 246
of the arm 236 adjacent a desired radial position of the disk 114,
for tracking. In one embodiment a typical read seek time of about
50 msec. or less is provided. The actuator body may also be
configured to provide for controllable motion in a vertical
direction 258 via pivot receptacle 262 engaging pivot 264, of the
optical arm 236 for tilting the arm to provide desired spacing of
the objective end 246 with respect to a surface of the disk 114,
e.g. for focus control. Preferably focus is provided while
maintaining the laser source and the objective 246 in a fixed
spatial relationship with respect to one another. For example, when
focus is effected by tilting the arm 236, the laser source remains
in the same, fixed spatial relationship, and remains the same
distance (e.g. measured along the optical path from the laser
source) with respect to the objective during tilt movements
(although both the laser source and the objective will move with
respect to the surface of the disk 114, during tilt movements).
Rotation about the vertical axis 256 can be provided by controlling
current through a coil 268, such as a bonded wire coil (e.g. for
reducing mass) . The coil 268 is positioned between parallel,
spaced-apart return plates 274a,b whose edges are coupled (e.g. by
an adhesive) to a permanent magnet such as a rare earth magnet,
272. Vertical motion 252 is provided by controlling current to a
coil 238 concentric with a center pole holder 278 mounted
concentrically with the hub or post receptacle 242 and positioned
on disk-shaped permanent magnet 276.
[0085] When, as in the depicted embodiment, tracking is performed
by rotating the arm 236 about a vertical axis (i.e. an axis
parallel to, but spaced from, the axis of rotation 237 of the disk
114) an embodiment of the present invention provides for
facilitating tracking by reducing the rotational moment of the
optical arm 236 to a relatively low value, such as less than about
5 gm-cm.sup.2, preferably less than about 1 gm-cm.sup.2. Features
that contribute to ease of tracking include reducing the number
and/or mass of components which are coupled to (and move with) the
arm, and positioning components relatively close to the arm
rotational axis 614, and preferably such that the center of mass of
the optical arm assembly is at or close to the rotation axis
614.
[0086] Preferably, a detent/latch 284 includes a cut-out 286 for
engaging a portion of the arm 236 and holding it in a parked
position, e.g. when the cartridge 112 is withdrawn from the
cartridge receptacle area 252. A camming surface 288, e.g.
protruding through an opening 292 is moved, in response to
insertion of a cartridge 112 in the receiving area 252, to pivot
the latch 284, e.g. about latch axis 294 to a position disengaged
from the arm 236.
[0087] FIGS. 15a, b, c and d illustrate operation of a arm latch
284' according to an embodiment of the present invention. In the
embodiment of FIGS. 15a, b, c, d, the latch 284' has a lower
surface which includes a ramp 1512 defining a ramp angle 1516
leading to a detent 1518 configured to engage the upper surface of
the optical arm 236. Preferably, the detent is positioned and
shaped so that when the arm is engaged (as depicted in FIGS. 15a
and c), it is both retained (against vertical and lateral movement)
and retracted 1519 (so as to move the optical end of the arm away
from the cartridge or disk area. The latch is mounted to permit
pivotal movement about a latch pivot axis 1520. The distal end of
the latch 284' includes a sensing cam 1522. when a cartridge is
inserted in the drive 514, e.g. along cartridge plane 1524, the
edge of the cartridge engages the sensing cam 1522, causing the
latching arm to pivot about the latch pivot axis 1520 from the
engaged configuration shown in FIGS. 15a and c to the disengaged
configuration shown in FIGS. 15b and d. In the disengaged
configuration, there is sufficient clearance, with respect to the
latch, that the optical arm is free to move 1528 away from the
retracted position and is free to move laterally (for tracking)
and, in at least some configurations, vertically (e.g. for focus).
When the cartridge is withdrawn from the drive 514 the latching arm
is urged (e.g. by a spring, not shown) toward the engagement
position shown in FIGS. 15a and c, and the optical arm 236 is
guided toward the detent 1518, e.g. by the ramp 1512.
[0088] In one embodiment, in assembling the device depicted in FIG.
3 the motor 218 is affixed to the baseplate 214. The board 226 is
placed with the motor 218 protruding through the cutout 227. the
flex circuit 224 of the motor 218 attached to a connector on the
main board 226. The arm actuator and the optical arm are then
assembled, and the flex circuit 234 is then coupled to a connector
on the main circuit board 226.
[0089] In use, the cartridge 112 is inserted through a slot opening
so that the rails 312 engage the grooves 148 pushing the slide 152
back to position the shutter 144b in the open position 158 and to
rotate the latch 284 to disengage the arm 236. The disk 114 is
rotated by hub 222 of the spin motor 218. In response to signals
received through the connector 228, current is provided to coil 268
to rotate the arm 236 about the vertical axis 256 for tracking and
to pivot the arm for focus. Upon withdraw of the cartridge 112 from
the receiving area 252, the shutter 158 is automatically closed so
as to cover the window 146 and the arm 236 is automatically
latched.
[0090] In one embodiment, the drive depicted in FIGS. 4 and 5 has a
width 412 of about 52 mm, a height 512 of about 10.5 mm and a depth
414 of about 40 mm. The disk 114 preferably has a capacity of about
0.250 Gbyte for each surface of the disk using a 635 nm wave length
laser (with greater capacity being provided with a shorter-wave
length laser). In one embodiment, data is recorded using a minimum
spot size of 0.4 micrometers, a track pitch of 0.74 micrometers,
and achieves a data rate of about 1 Mbyte per second. In one
embodiment, the data outside diameter is about 29 mm, the data
inside diameter is about 11 mm providing a data area per side of
about 0.877 square inches (about 565 square mm). The disk rotation
speed is preferably about 73 revolutions per second. A number of
encoding schemes can be used, including, for example, {fraction
(8/16)} run-length limited (RLL), with Reed-Solomon error
correction code (ECC).
[0091] As depicted in FIG. 17, in one embodiment an optical
configuration according to the present invention includes a
laser/detector and optics assembly 1713, preferably positioned in
the electro-optics module 237, and objective optics 1715,
positioned at the objective end of the optics arm 236. In one
embodiment, the laser source is provided on a semiconductor chip
1701, such as a GaAs chip. In a preferred embodiment, the laser
source is a vertical cavity surface emitting laser (VCSEL) 1713.
Examples of VCSELs are described in U.S. Pat. Nos. 5,757,741 and
5,831,960. Preferably, a photodetector array 1714, such as a
quadrant photodetector array or a .phi. photodetector array, is
formed integrally with the laser, on the chip 1701, i.e. in an
integrated device, the VCSEL and photodetector(s) are formed on the
same substrate, typically a GaAs substrate. In one embodiment, the
detector is a metal-semiconductor-metal (MSM) type. Integration
provides a number of benefits. In general, integration of multiple
components is relatively economical. Integration makes it possible
to precisely determine the relative positions of the laser 1713 and
detector 1714, both axially (e.g. to position in a common plane)
and laterally (e.g. to provide a desired spacing 1812 (FIG. 18),
such as about 0.05 mm). This can be usefull in reducing or
eliminating the need for positional adjustments of components
during assembly or maintenance of drives. Some or all of these
benefits may also be provided by using a hybrid device, in which
the laser and photodetector(s) are formed separately, then mounted
on a common substrate. During data writing, a relatively high
power, preferably vertically, linearly polarized beam 1710 is
emitted from the laser. This is generally a divergent beam which
(if necessary) may be collimated (or have its divergence reduced)
by a lens 1709. In the depicted embodiment, lens 1709 is provided
on optic part 1702. Optic part 1702 may be glass or plastic and may
contain conventional (e.g. refractive) or diffractive components.
Optic part 1702 can be made in a number of ways such as by molding.
etching or machining. The beam 1710 then passes through a
birefringent component 1703. In the depicted embodiment, the
outgoing beam is undeviated when linearly vertically polarized. The
birefringent component 1703 can be any birefringent material, such
as calcite, suitably transparent for the application (e.g. at the
wavelength(s) of the light beam 1710). The beam is converted to
circular polarization by an optical quarter wave retarder 1704. The
beam 1710 then traverses the main length of the optical arm 236,
before reaching turning prism (or mirror) 1705, which may be, e.g.,
glass or plastic. To assist in reducing the rotational moment of
the optical arm assembly, the prism 1705 (and lens 1706) are
preferably as small as possible. An additional advantage of making
the prism 1705 and lens 1706 small, is that smaller components are
more readily made of (relatively less dense) acrylic or plastic.
The beam 1710 is focused to a tight spot by the (diffractive or
refractive) objective lens 1706. onto the recording layer of the
disk 1707. Preferably, the lens 1706 is positioned relatively close
to the prism 1705, to facilitate providing a drive 514 with a small
thickness 512. In one embodiment, the prism 1705 and lens 1706 are
integrally formed (made as or from a single piece).
[0092] During writing (at high power) and reading (when the laser
power is reduced so as to ensure that no writing occurs), the beam
is reelected back from the disk 1707 with substantially a reversed
direction of rotation of polarization. The power of the reflected
beam will vary depending on whether or not the area of the
recording layer on which the beam is focused, contains a
previously-written spot. The reflected beam retraces its path
through the objective lens 1706, prism 1705 and along substantially
the same path 1712, Upon reaching the retarder 1704, the beam is
converted to a horizontal linear polarization. When it encounters
the birefringent component 1703, the beam shears in a horizontal
direction, 1716, exiting the birefringent component as beam 1711,
parallel to the original beam 1710, but displaced by a small amount
1812, such as about 100 to 200 micrometers. When the reflected beam
enters the optic component 1702, it encounters an astigmatic
element 1708, such as a cylindrical lens, before being projected
onto the detector array 1714. If the astigmatic element 1708 is a
cylindrical lens, then the detector array 1714 should be a
conventional quadrant configuration.
[0093] The signals derived from the detector array, in various
combinations, can be used to form the focus and tracking signals
(or focus and tracking error signals) required for the focus (e.g.
by pivoting about a focus pivot axis 1717, as described below) and
tracking servo systems1216c, 1136, as well as the recovered stored
digital data, in a manner that will be understood to those of skill
in the art after understanding the present disclosure.
[0094] In the embodiment of FIGS. 16 and 17, polarization control
is used to provide both efficient read and write paths (potentially
approaching 100% efficient), and good isolation of the laser 1714
from reflected light 1711 (which can otherwise make laser output
unstable and lead to noisy signals). Other embodiments are
possible. For example, the laser and detector array can be provided
as separate devices, e.g. on separate substrates (non-integrated),
and in this configuration it may be economically or otherwise
desirable to use an edge-emitting laser. A polarizing beam
splitter, polarizing cube, or Wollaston prism or the like may be
used to direct the returning beam 1711 to a separate detector
array. It is also possible to provide a system which does not use
polarization methods, as depicted in FIG. 19. In the embodiment of
FIG. 19, unpolarized outgoing beam 1920 is collimated (or its
divergence is reduced) by lens 1918 on the surface of multi-optic
1916. The beam passes through grating 1919 which deflects a small
portion out of the main beam into some angle (not shown). This
deflected portion is discarded from the outgoing beam. Upon return
from the disk, grating 1919 deflects a portion towards a combined
grating/lens element 1917, which directs the returning light 21 to
detector array 1714. The grating/lens element 1917 may, as in the
embodiment of FIGS. 17 and 18, have an astigmatic function (in
which case detector array 1714 is a quadrant configuration). The
system of FIG. 19 does not require any specific polarization of the
laser.
[0095] FIGS. 24A and B and 25A and B illustrate other
configurations of optical arms, and placement of optics components,
according to embodiments of the present invention. In the
embodiment of FIGS. 24A and B, substantially all the optical
components are positioned on-axis, near the objective end of the
arm 2407. In the depicted embodiment, the arm 2407 has a flanged or
inverted-U shape or inverted channel shape. Positioning all the
components together assists in avoiding optical alignment problems
that may occur as a result of movement or vibration (e.g.
mechanical resonance) in the arm. In the depicted embodiment, the
objective 2401, a spacer 2402, refractive/diffractive element(s)
2403 and laser/photodetector unit 2304 (bearing a preferably
integrated laser and photodetector chip 2408) are mounted in-line
e.g. through an opening 2409 at the objective end of the arm 2407.
In the depicted embodiment, the objective 2401 is provided with a
mounting/stop flange 2405, e.g. for limiting penetration of the
objective through a cartridge window or other opening. Pins 2410 or
other connectors of the laser/photodetector unit 2304 are coupled,
e.g. via a flex circuit 2406, to signal processing, power and/or
drive circuitry. The embodiment of FIGS. 25A and B is similar to
that of FIGS. 24A and B (i.e. provides for substantially all
optical components at or near the objective end of the arm 2407),
except that the objective 2501 includes (or is coupled to) a
turning prism 2511, and not all optical components are on-axis.
FIG. 25A also includes an illustration of a beam splitter 2512.
[0096] FIGS. 20A and B illustrates one embodiment of a focus and
tracking servos. FIG. 20A illustrates a method and apparatus
involving tilting of the optical arm. In this embodiment, the arm
236 pivots about pivot pin 264 such that the objective lens 1706 is
positioned appropriately above the moving disk. A current in coil
238 generates a magnetic field which repels or attracts permanent
magnet 242 which is mounted in a fixed position with respect to the
baseplate of the assembly 214. By controlling the amount of current
in coil 238, the degree of tilt may be controllably selected, e.g.
to provide any desired tilt angle 2012 (positive or negative)
between a first attitude 2014 and a second attitude 2016, so as to
control the distance from the objective lens 1706 to the recording
layer, and thus control the focus.
[0097] FIG. 20B is an end view depicting the optical arm rotary
tracking servo (in a view directed toward the objective end of the
arm). Coil 268 is positioned between two plates 274a, b which guide
and concentrate the magnetic field from permanent magnet 272 such
that a current in coil 268 produces a torque about tracking axis
256.
[0098] Other embodiments for a focus servo mechanism are
illustrated in FIGS. 21A and B, 23 and 27. In FIG. 21A a ball
bearing 2102 facilitates rotation about tracking axis 256. Coupling
piece 2101 is bonded to piezo-electric transducer 2103, which is in
turn mounted in a fixed position with respect to the assembly
baseplate 214. Focus position is adjusted by applying voltage to
transducer 2103, causing it to expand and contract, thus changing
the position of arm 236 relative to the baseplate (and the hub and
disk, in turn).
[0099] In FIG. 23, the optical arm 2302 is held in a tilt pivot
bearing housing 2304 pivotally mounted for pivoting about tilt
bearing axis 2309. An optic housing 2303 holds optics such as a
(preferably integrated) laser/photodetector assembly 7
(communicating with signal processing/power circuits via a flex
circuit 2308a), a beam splitter 6 and refractive/diffractive
element(s) 5. The objective end of the arm holds an
objective/turning prism assembly 2301. Focus voice coil 2310, which
receives focus drive signals, e.g. via a flex circuit 2308b, is
positioned between two plates (only one of which, 2311, is shown)
which guide and concentrate a magnetic field (e.g. from a permanent
magnet, not shown) such that a current in coil 2310 produces a
torque about the focus axis 2309.
[0100] In the embodiment of FIG. 27, focus is achieved by adjusting
the length of the optical path from the laser 2712 to the objective
2714. In the depicted embodiment, the laser 2712 is mounted on a
sleeve 2716 which is sized and shaped to slidably fit over the near
end 2718 of the optical arm 2722. When a coil 2724 on the sleeve
2716 is provided with controllable current (e.g. via flex circuit
2726 coupled to power or control circuitry, not shown, and/or
demodulator and other electronics 2728, shown coupled to the sleeve
2716, in the depicted embodiment), an attractive/repulsive force
developed by interaction with an annular permanent magnet 2732
causes the sleeve to controllably move fore or aft in an axial
direction 2734, affecting focus.
[0101] In the embodiment of FIG. 21B, ball bearing 2102 provides
rotation capability. Coupling piece 2101 is held by flexure plates
2106, attached to rigid block 2107, which is attached to the
baseplate 214. A current in coil 2105, attached to the coupling
piece 2101, creates a magnetic field which attracts or repels that
of the permanent magnet 2104 (via an air gap). The force causes
plates 2106 to bend in an "S" shape, and therefore alter the height
of the arm 236 above the disk. The material and dimensions of the
plates 2106 are important, since they must have a suitable
restitution spring force to provide sufficient servo bandwidth, but
should be designed to minimize track position crosstalk. For
example, sideways flexibility, e.g. due to narrow plates, would
appear as tracking error and/or as focus/tracking crosstalk.
[0102] In light of the above description, a number of advantages of
the present invention can be seen. The present invention provides
sufficient capacity to store approximately 0.5 Gbytes or more of
data (corresponding to approximately 100-200 full color,
high-resolution images) on two surfaces of an optical disk
cartridge 112 about 35 mm square and about 3 mm thick, so as to be
readily accommodated in a digital camera 2212 (FIG. 22) having a
size, shape and weight not substantially exceeding size, shape and
weight of corresponding film cameras (such as typical 35 mm film
cameras), preferably being substantially a pocket-sized device, as
discussed above. The present invention provides drive 514 for an
optical recording medium having a thickness 512, width 2214 depth
2216 and weight so as to be readily accommodated in a digital
camera 2212 having a size, shape and weight not substantially
exceeding size, shape and weight of corresponding film cameras. In
one embodiment, the thickness 521 and width 2214 of the drive are
substantially equal to or compatible with a Type III PCMCIA
opening, such as being about 10 mm or less in thickness 521 and
about 52 mm or less in width 2214. In one embodiment the depth 2216
of the drive is about 40 mm or less. In one embodiment, the mass of
the drive is less than about 50 gm, preferably less than about 35
gm. The present invention provides an optical data storage
cartridge which can be used in connection with a first-surface
writeable optical storage medium. Preferably the medium is formed
as a first-surface medium, i.e. in which the writeable medium is
either uncoated or provided with a coating sufficiently thin that
there is substantially no optical effect of the coating. Because of
the relatively unprotected nature of the first-medium, it is
particularly useful to protect the preferably removable disk by
encapsulation or envelopment in a cartridge, preferably one which
can be sealed, e.g. via shutters and/or a hub seal 117 to protect
from dust, particulates, contact and the like. Preferably, the
medium is substantially conductive which is believed to assist in
avoiding static or other charge accumulation which can undesirably
attract dust or other contaminants.
[0103] As noted above, first-surface recording does not have the
scratch/contamination advantage of conventional optical disks, so
the media are advantageously protected by housing in an enclosed
cartridge. This is not a significant disadvantage in the case of
small, approximately 30 mm diameter, disks intended for portable
consumer devices, since it would be advantageous to protect optical
disks of this size by a cartridge regardless of the presence or
absence of a protective layer, due to the heavy direct handling
they would otherwise receive on their optical surfaces. However,
the optical solution is still preferred over the magnetic because
to achieve high density, magnetic storage requires very low flying
heights (such as about 0.025 to 0.05 .mu.m) which is substantially
incompatible with a removable cartridge since it is believed dust
cannot economically be excluded at this level, even within a
cartridge.
[0104] A first-surface media requires only a single substrate, that
may be typically injection-molded polycarbonate or acrylic, onto
which the recording layer or stack is deposited. Other substrate
material can be used such as aluminum or other metals, fiberglass
and the like. A double sided version of the disk simply has a
recording layer deposited on both surfaces. This is in contrast to
DVD-R where the use of 2 sides requires 2 substrates, with their
appropriate stacks, to be bonded together. Particularly in the case
of WORM media, first-surface storage can be maximally simple,
perhaps with the recording layer and a single overcoat deposited on
the disk for each recording surface.
[0105] The simplest structure, comprising a layer of WORM phase
change media on a substrate with possibly only a simple single
layer anti-reflective overcoat, is advantageous because of
structure simplicity, wide tolerances such as layer thicknesses
(not tuned), as well as insensitivity to wavelength (making future
shorter-wavelength systems easily compatible). In particular, it is
noted the response of InSbSn is very flat over the visible and
near-infrared spectrum. Additionally, the tolerance to media tilt,
substrate thickness and lack of substrate birefringence problems
ease the drive design and enable higher storage densities through
higher NA's. All of these features reduce the cost of the media and
drive.
[0106] 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, it is possible
to provide an optical data storage cartridge which is removable,
has a relatively small size and relatively large capacity without
providing for writing on both sides of the disk. Although the
cartridge of the present invention has been described in connection
with a particular type of drive, it is possible to use the
cartridge of the present invention in connection with other sizes,
shapes, or techniques of drives.
[0107] Although the present invention has been described in the
context of providing optical data storage for use in connection
with digital cameras, the optical storage device and system of the
present invention can also be used for other 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, 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. In one embodiment writeable media is provided in a
grooved, premastered form, preferably with embedded (e.g. molded)
servo and data header information.
[0108] Although much of the description above was concerned with
recording image data onto the medium, it is contemplated that
digital cameras will commonly be used for viewing stored images
(either stored by the same digital camera, or pre-recorded, e.g.
mass-distributed pre-recorded media), and accordingly, the drive
preferably provides both read and write capability. In general
features, data or other information can be pre-provided (i.e.
provided already on the disk when it is purchased by or otherwise
provided to the end-user) by pre-recording (which generally
involves sequential recording of a data stream or other
information) or embedding (which generally involves providing some
or all the data substantially simultaneously, such as by molding,
stamping, printing, embossing and the like). In addition to
pre-providing data (e.g. content, such as images, music, programs,
and the like), in at least some embodiments, servo, formatting or
other non-content, informational or supplemental features may be
pre-provided (i.e. provided in or on the media as sold or
distributed to the end user). Examples of such information or
features include sector information or marks, track-following
features, identification or characteristics information (such as
data density or data format information, content identifiers and
the like), test features such as read test patterns write test
areas or cells, grooves and/or lands, other servo data and the
like. Provision of format or servo information by a process of
molding-in features or information (as opposed to recording the
information) is referred to herein as hard-formatting. It is
contemplated the pre-provided or pre-recorded media, according to
embodiments of the present invention, will be mass-produced in a
relatively rapid fashion, such as using a stamping, embossing or
printing-like process to impart the desired pre-recorded data on a
(preferably first-surface media) disk, which is then mounted in a
cartridge. Thus one advantage of the present invention over devices
such as video or audio tape devices is that pre-recorded data can
be reproduced substantially all-at-once (as opposed to
sequentially). Any of a variety of kinds of data can be
pre-provided and stored or distributed using the devices and
techniques of the present invention, including, but not limited to
still images, video, motion pictures, music, voice data, computer
programs and/or data, personal information or data such as
identification, password or encryption/decryption data, and the
like. The cartridges are then mass-distributed. The pre-provided or
pre-recorded media preferably can be used in either read-write
equipment (e.g. a digital camera), or read-only equipment, such as
drives which have only a low-power laser capability (insufficient
to write data on a disk). It is contemplated such read-only devices
may be part of, or coupled to, any of a variety of personal
electronic devices, or other electronic devices, 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.
[0109] It is further contemplated that some or all features of the
present invention can be used in connection with media and/or
drives which are configured to be re-writeable. Drives configured
to provide re-writeability may be configured to erase
previously-written data either in a separate erase pass over the
data, or "on the fly," substantially as (or just before) the new
data is written. It is contemplated that re-writeability may be
particularly useful in connection with applications involving data
which changes often, such as personal, and/or credit or other
financial data, certain types of computer data, and the like.
Although it would be advantageous to provide for compatibility of
various types of media with various types of drives, it is possible
there may be some degree of incompatibility, e.g. it may be that a
re-writeable disk can not be read by certain read-only drives, and
the like.
[0110] Although the figures illustrate one possible orientation of
the cartridge and drive, with the disk horizontal, and the optics
drawn below the disk, the device can be otherwise oriented, e.g.
with the disk vertical angled, and/or the arm above or lateral to
the disk. Although an embodiment has been described in which the
cartridge is used in connection with a drive having an actuator for
reading or writing on one surface of the disk at a time (so that,
recording on an opposite surface involves removing, rotating and
reinserting the cartridge) it is also possible to configure a drive
with two actuator arms, one for writing on each surface, such that
read/write can be performed on both surfaces without the need for
rotating the disk and/or can be performed on both surfaces at the
same time. Although a tube-shaped optical arm and a u-shaped or
channel arm are depicted, other structures are possible, such as an
open cage or framework, a rod, a polygonal cross-sectional shape
and the like. Although embodiments of the present invention have
described providing a single actuator arm for writing on a given
surface of the disk, it is also possible to configure a drive which
provides two or more different actuator arms for writing on the
same surface of the disk, e.g. to improve transfer rates, access
times and the like. Although a substantially arcuate window in the
cartridge surface has been described, it is also possible to
provide other sizes or shapes of windows such as providing a larger
window, since making the window larger will still provide the
access minimally required to the disk. Although the drive has been
described as substantially enclosed by a housing or chassis,
baseplate and cover 214, 212, 216, it is possible to provide the
drive in a substantially open (unenclosed) configuration, e.g. if
it is intended to be normally non-removably housed in a larger
structure, such as a digital camera. In one embodiment one or more
circuit boards provide the main rigid structure, to which other
components are coupled. Although write-once media are described,
and may be preferred for some purposes (to avoid the potential for
accidental data loss), some or all aspects of the present invention
can also be used in connection with re-writeable media (many
re-writeable media use phase-change recording materials, and, as
noted above, at least some media presently preferred in the present
invention are also phase change media).
[0111] Although digital cameras are discussed in the context of
storing image information, it is possible to use the data storage
system and medium described herein, within digital cameras, for
storing other items (exclusively, or in combination with image or
other information), such as audio recorded near the time the images
are taken, date, time, location, frame number, image recording
parameters (f-stop and the like) and similar information, e.g. to
identify the images, and the like.
[0112] Although an embodiment is depicted in which the laser source
is laterally displaced from the detector , As depicted in FIG. 26,
it is also possible to construct an operable device in which the
detector, such as a 100 detector 2612, coaxially surrounds the
laser source, such as a VCSEL 2614, preferably integrated
therewith. Such a coaxial device can eliminate the need for devices
and procedures for laterally offsetting the reflected beam. In the
depicted embodiment a diffractive collimator/torus lens 2616 is
provided, such as being coupled to (or integrated with) the turning
prism 2632 and objective 2634. The torus lens 2612 is positioned
and configured such that the reflected beam 2618 is wider, upon
arrival at the laser/detector chip 2622, than the outgoing beam
2624 emitted by the laser 2614. Accordingly, sufficient power from
the reflected beam 2618 falls on the coaxial detector 2612 that the
data on the disk 2626 can be read, and usable focus and tracking
signals can be obtained. Further, only a relatively small portion
of the reflected beam 2618 reaches the laser 2614, helping to avoid
feedback or other undesired effects. Although the presence of the
torus lens 2612 may create a ring about the read/write spot,
relatively little power (such as about 10%) is in the ring, so that
there is little unwanted effect.
[0113] 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.backslash.or reducing cost of implementation.
[0114] 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.
* * * * *