U.S. patent application number 11/274392 was filed with the patent office on 2006-06-22 for optical media, read inhibiting agents and methods of making and using same.
This patent application is currently assigned to Flexplay Technologies, Inc.. Invention is credited to Louis Cincotta, Arthur R. III LeBlanc, Edward Lindholm, Joseph W. Paulus, Robert F. Thompson.
Application Number | 20060136947 11/274392 |
Document ID | / |
Family ID | 36337322 |
Filed Date | 2006-06-22 |
United States Patent
Application |
20060136947 |
Kind Code |
A1 |
LeBlanc; Arthur R. III ; et
al. |
June 22, 2006 |
Optical media, read inhibiting agents and methods of making and
using same
Abstract
Apparatuses, products, devices and methods of manufacture
consistent with the invention include optically readable media with
at least one mechanism, chemical, agent, and/or process for
limiting the time period that at least a portion of encoded
information can be read and/or accessed by an optical beam and/or
reader capable of reading the encoded information.
Inventors: |
LeBlanc; Arthur R. III;
(Kennebunk, ME) ; Thompson; Robert F.; (Kennebunk,
ME) ; Cincotta; Louis; (Andover, ME) ;
Lindholm; Edward; (Brookline, MA) ; Paulus; Joseph
W.; (Portland, ME) |
Correspondence
Address: |
MORRIS MANNING & MARTIN LLP
1600 ATLANTA FINANCIAL CENTER
3343 PEACHTREE ROAD, NE
ATLANTA
GA
30326-1044
US
|
Assignee: |
Flexplay Technologies, Inc.
New York
NY
|
Family ID: |
36337322 |
Appl. No.: |
11/274392 |
Filed: |
November 14, 2005 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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60627787 |
Nov 12, 2004 |
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60627638 |
Nov 12, 2004 |
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60627209 |
Nov 12, 2004 |
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60627386 |
Nov 12, 2004 |
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60711616 |
Aug 26, 2005 |
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Current U.S.
Class: |
720/619 ;
G9B/23.087; G9B/7.005; G9B/7.024; G9B/7.168; G9B/7.185 |
Current CPC
Class: |
G11B 20/00086 20130101;
G11B 20/00608 20130101; G11B 2020/1288 20130101; G11B 7/2595
20130101; G11B 7/241 20130101; G11B 23/282 20130101; G11B 2220/2579
20130101; G11B 7/2533 20130101; G11B 7/259 20130101; G11B 2220/2541
20130101; G11B 7/26 20130101; G11B 7/256 20130101; G11B 20/0084
20130101; G11B 7/24038 20130101; G11B 7/2534 20130101 |
Class at
Publication: |
720/619 |
International
Class: |
G11B 17/04 20060101
G11B017/04 |
Claims
1. An optical medium readable by at least one pre-selected optical
beam comprising: a first substrate; a first data storage layer
proximate to said first substrate, wherein said first data storage
layer comprises an encoded information receiving layer and a
reflective layer; and a read inhibiting agent, said read inhibiting
agent in communication with said first data storage layer, wherein
said read inhibiting agent allows access to at least a portion of
said first data storage layer for a predefined period of time and
after such predefined period of time said read inhibiting agent
irreversibly prohibits access to said at least a portion of said
first data storage layer; wherein said optical medium is disc
shaped having an inner diameter and an outer diameter; wherein said
first read inhibiting agent is localized to at least one of (i) the
inner diameter and (ii) to a wedge shape, wherein the wedge shape
is widest at the outer diameter and narrowest towards the inner
diameter.
2. The optical medium according to claim 1, wherein said first data
storage layer is a selected from one of the following optical
medium formats Read Only Memory (ROM), Write Once, Read Many
(WORM), Interactive (I), Erasable (E), CD-ROM, CD-WORM, CD-I, DVI,
CD-EMO, OD3, ODD, Video Disk, IVD, Blu-ray, HD-DVD, DVD, DVD-R,
DVD-Video, DVD-RAM, DVD-Audio, DVD-RAM, DVD-RW, DVD+RW, DVD+R,
DVD-Video, SACD, holographic, and holographic versatile disc.
3. An optical medium readable by at least one pre-selected optical
beam comprising: a first substrate; a first data storage layer
proximate to said first substrate, wherein said first data storage
layer comprises an encoded information receiving layer and a
reflective layer; and a read inhibiting agent, said read inhibiting
agent in communication with said first data storage layer, wherein
said read inhibiting agent allows access to at least a portion of
said first data storage layer for a predefined period of time and
after such predefined period of time said read inhibiting agent
irreversibly prohibits access to said at least a portion of said
first data storage layer; wherein said first data storage layer
comprises instructions that direct where said at least one
pre-selected optical beam is located in relation to said first data
storage layer, the order the regions in the first data storage
layer are accessed, and the length of time the pre-selected optical
beam remains located in a particular region of the first data
storage layer.
4. The optical medium according to claim 3, wherein said
instructions are encoded on the optical medium during the authoring
of said first data storage layer of the optical medium.
5. The optical medium according to claim 4, wherein said
instructions direct the pre-selected optical beam to read regions
of said optical medium where said first read inhibiting agent is
located.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] Priority is hereby claimed under 35 U.S.C. 119(e) from U.S.
Provisional Patent Application No. 60/627,787 filed Nov. 12, 2004;
U.S. Provisional Patent Application No. 60/627,638 filed Nov. 12,
2004; U.S. Provisional Patent Application No. 60/627,209 filed Nov.
12, 2004; U.S. Provisional Patent Application No. 60/627,386 filed
Nov. 12, 2004; and U.S. Provisional Patent Application No.
60/711,616 filed Aug. 26, 2005. The disclosures of all of the above
prior Patent Applications are hereby incorporated by reference as
if set forth herein in their entirety.
FIELD OF THE INVENTION
[0002] The present invention relates generally to optically
readable media. More specifically, apparatuses, products, devices
and methods of manufacture consistent with the invention are
disclosed that include numerous configurations and/or novel designs
for limiting the time period that at least a portion of the encoded
information stored on the optically readable media can be read
and/or accessed by an optical beam and/or reader capable of reading
information encoded thereon.
BACKGROUND
[0003] Optical, magnetic and magneto-optic media are primary
sources of high performance storage technology, which enable high
storage capacity coupled with a reasonable price per megabyte of
data stored. The use of optical media has become widespread in
audio, video, and computer data storage applications in such
formats as compact disc (CD), digital versatile disc (DVD,
including multi-layer structures like DVD-5, DVD-9 and multi-sided
formats such as DVD-10, and DVD-18), magneto-optical disc (MO), and
other write-once and re-writable formats such as CD-R, CD-RW,
DVD-R, DVD-RW, DVD+RW, DVD-RAM, and the like, hereinafter
collectively "data storage media". In these formats, data are
encoded onto a substrate into a digital data series. In
pre-recorded optical media, such as CD, the data are typically pits
and grooves embossed on the surface of a plastic substrate using a
method such as injection molding, stamping or the like.
[0004] In recordable media, the data are encoded by laser, which
illuminates an active data layer that undergoes a phase change,
thus producing a series of highly reflecting or non-reflecting
regions making up the data stream. In these formats, a laser beam
first travels through a plastic substrate before reaching the data
layer. At the data layer, the beam is either reflected or not, in
accordance with the encoded data. The laser light then travels back
through the plastic and into an optical detector system where the
data are interpreted.
[0005] In some applications, it is desirable to have a limited life
for an optical disc. For example, sample computer programs are
provided to potential customers in order to entice them to purchase
the software. The programs are intended to be used for a limited
period of time. Additionally, music, movies, and other forms of
digital entertainment are currently rented for a limited time
period. In each of these applications and others, when that time
has expired, the disc must be returned. A need exists for
machine-readable optical discs that do not need to be returned at
the end of a rental period. Limited-play discs provide a solution
to this problem.
[0006] Several approaches have been proposed to make a limited play
optical disc based on a layer that changes from a non-interfering
state (transparent) where it does not interfere with the reliable
reading of the information on the optical disc, via an
interrogating beam of light, to an interfering state (opaque) where
the layer interferes with the optical reading of the data on the
disc. The interference with the reading light source may be due to
the layer becoming dark, reflective, highly birefringent, pitting,
corroding, bending, changing refractive properties or any
combination of these. (See for example, U.S. Pat. No. 6,011,772 and
U.S. Pat. No. 5,815,484 and herein incorporated by reference in
their entirety). It should be pointed out that it is not essential
in all applications that the interfering layer cover an entire
surface of the disc. It may be desirable to inhibit only the
reading of areas containing critical information content.
SUMMARY OF INVENTION
[0007] In one embodiment of the invention, the stimulus triggering
the reaction is exposure to atmospheric oxygen. Upon exposure to
oxygen, a reactive material, which is essentially colorless, is
oxidized to form an opaque or semi-opaque layer. Data storage media
with the opaque/semi-opaque layer can no longer be played in media
players. By adjusting the time it takes to turn opaque, this method
can be used to provide limited-play data storage media having the
desired life for the given application.
[0008] In one embodiment consistent with the invention a limited
life CD, CD-ROM, and/or CD-R optical disc utilizing a corrosive
agent and/or agent for degrading the integrity of a reflective
layer and/or portion there of located in a layer and/or region
adjacent to the reflective layer of the disc is described.
[0009] In another embodiment a limited life CD, CD-ROM, and/or CD-R
utilizing a dye in the optical path of the 780 nm laser is
described. The optical disc employs two substrates bonded together
with a dye adhesive while the data layer resides on top of the
substrate stack at approximately 1.2 mm above the bottom surface of
the layered disc.
[0010] In yet another embodiment a limited play DVD combined with a
CD data layer or recordable layer is described. In yet still a
further embodiment a corrosive agent and/or agent for degrading the
integrity of a reflective layer and/or portion thereof located
adjacent to one or more reflective layers of the DVD and/or CD data
layer is described.
[0011] In a further embodiment a dye material is incorporated in
the optical path of the reading laser.
[0012] In another embodiment a permanent play and/or recordable
layer survives after the limited play mechanism and/or process is
activated and the limited play layer(s) has ceased to play.
[0013] In an embodiment consistent with the invention a limited
play DVD including recordable and dual layer disc halves using a
corrosive material and/or an agent for degrading the integrity of
at least one reflective layer and/or portion thereof in a layer
adjacent to any reflective layer within the optical disc is
disclosed. In an overlapping embodiment a permanent play and/or
recordable DVD layer survives after the limited play mechanism is
activated and the limited play layer(s) has ceased to play.
[0014] In another embodiment a limited play DVD including
recordable and dual layer disc halves using a dye material to
inhibit the ability of the reading laser to read a data layer
within the optical disc is disclosed. In an overlapping embodiment
a permanent play and/or recordable DVD layer survives after the
limited play mechanism is activated and the limited play layer(s)
has ceased to play.
[0015] In a further embodiment consistent with the invention an
optical disc combining HD-DVD, HD-DVD-R/RW and/or DVD/DVD-/+R/RW
data layers within one disc where any one or more of the data
and/or recordable layers is limited play is disclosed. In an
overlapping embodiment, the limited play mechanism is a corrosive
agent that is adjacent to one or more reflective layer. In a
further overlapping embodiment a permanent play and/or recordable
DVD layer survives after the limited play mechanism is activated
and the limited play layer(s) has ceased to play. In yet another
overlapping embodiment the read limiting agent is a dye that
inhibits the reading of at least one data layer. In an overlapping
embodiment with the dye, a permanent play and/or recordable layer
survives after the limited play mechanism is activated and the
limited play layer(s) has ceased to play.
[0016] In another embodiment an optical medium combining HD-DVD,
HD-DVD-/+R/RW and CD, CD-ROM, CD-R, and/or CD-RW data layers within
one disc where any one or more of the data and/or recordable layers
is limited play is disclosed. The limited play mechanism is
selected from a corrosive material, dye material and/or
combinations thereof. If the limited play mechanism is a corrosive
material it is located adjacent to at least one reflective layer.
In an overlapping embodiment a permanent play and/or recordable
layer survives after the limited play mechanism is activated and
the limited play layer(s) has ceased to play.
[0017] In an embodiment consistent with the invention an optical
medium combining Blu-ray and DVD data and/or recordable layers
within one disc where any one or more of the data and/or recordable
layers is limited play is disclosed. The limited play mechanism is
selected from a corrosive material, dye material and/or
combinations thereof. If the limited play mechanism is a corrosive
material it is located adjacent to at least one reflective layer.
In an overlapping embodiment a permanent play and/or recordable
layer survives after the limited play mechanism is activated and
the limited play layer(s) has ceased to play.
[0018] In another embodiment an optical medium combining Blu-ray
and HD-DVD data and/or recordable layers within one disc where any
one or more of the data and/or recordable layers is limited play is
disclosed. The limited play mechanism is selected from a corrosive
material, dye material and/or combinations thereof. If the limited
play mechanism is a corrosive material it is located adjacent to at
least one reflective layer. In an overlapping embodiment a
permanent play and/or recordable layer survives after the limited
play mechanism is activated and the limited play layer(s) has
ceased to play.
[0019] In another embodiment consistent with the invention limited
play Blu-Ray optical media are disclosed.
[0020] In a further embodiment consistent with the invention
limited play HD-DVD optical media are disclosed.
[0021] In yet a further embodiment consistent with the invention
authoring techniques are employed in conjunction with read
inhibiting agent(s).
[0022] In another embodiment consistent with the invention the read
inhibiting agent is localized to sub-regions of an optical
medium.
[0023] In a further embodiment consistent with the invention
methods and processes of making limited play optical media are
disclosed.
[0024] These and other features and advantages of the present
invention will be presented in more detail in the following
detailed description and the accompanying figures which illustrate
by way of example the principles of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0025] FIG. 1 illustrates a cross section of an optical medium of a
limited life HD-DVD embodiment consistent with the present
invention
[0026] FIG. 2 illustrates a cross section of an optical medium of a
limited life Blu-ray disc embodiment consistent with the present
invention.
[0027] FIG. 3 illustrates a cross section of an optical medium of a
limited life Blu-ray disc embodiment consistent with the
invention.
[0028] FIG. 4 illustrates a cross section of a combined CD and DVD
embodiment consistent with the invention.
[0029] FIG. 5 illustrates a cross section of a combined CD and DVD
embodiment consistent with the invention.
[0030] FIG. 6 illustrates a cross section of a combined CD and DVD
embodiment consistent with the invention.
[0031] FIG. 7 illustrates a cross section of a limited play DVD
with a CD recordable layer embodiment consistent with the
invention.
[0032] FIG. 8 illustrates a cross section of a DVD and recordable
CD embodiment consistent with the invention.
[0033] FIG. 9 illustrates a cross section of a DVD recordable and
DVD ROM disc embodiment consistent with the invention.
[0034] FIG. 10 illustrates a cross section of a DVD recordable and
DVD ROM disc embodiment consistent with the invention.
[0035] FIG. 11 illustrates a cross section of a limited play DVD
with a permanent play DVD read from the bottom side embodiment
consistent with the invention.
[0036] FIG. 12 illustrates a cross section of a limited play DVD
with a permanent play DVD layer embodiment consistent with the
invention.
[0037] FIG. 13 illustrates a cross section of a limited play HD-DVD
dual layer top substrate bonded with a DVD embodiment consistent
with the invention, wherein either or both the HD-DVD layer or the
DVD layer are limited life layers.
[0038] FIG. 14 illustrates a cross section of a Blu-ray data
layer(s) combined with DVD data and/or recordable layers embodiment
consistent with the invention.
[0039] FIG. 15 illustrates a cross section of a Blu-ray data
layer(s) combined with DVD data and/or recordable layers embodiment
consistent with the invention.
[0040] FIG. 16 illustrates a cross section of a Blue-ray top data
layer (dual layer shown) combined with HD-DVD data layer (dual
layer shown) read from the bottom embodiment consistent with the
invention.
[0041] FIG. 17 illustrates a cut away top view with the read
inhibiting agent localized to a prescribed region consistent with
the invention.
[0042] FIG. 18 illustrates a cut away top view with the read
inhibiting agent localized to a prescribed region consistent with
the invention.
[0043] FIG. 19 illustrates a cut away top view with the read
inhibiting agent localized to a prescribed region consistent with
the invention.
[0044] FIG. 20 illustrates a cut away top view with the read
inhibiting agent localized to a prescribed region consistent with
the invention.
[0045] FIG. 21 is a graphic illustrating the decay kinetics of a
read inhibiting agent in the presence of various film and/or
barrier materials consistent with the present invention.
[0046] FIG. 22 is a graphic illustrating the decay kinetics of a
read inhibiting agent consistent with the present invention.
[0047] FIG. 23 illustrates two disc cross sections illustrating the
placement of barrier films in an optical medium in accordance with
the present invention.
[0048] FIG. 24 is a graphic illustrating the optical transmission
of the L0 substrate with 1% MBI consistent with the present
invention.
[0049] FIG. 25 is a graphic illustrating the optical density of the
adhesive in accordance with the present invention.
[0050] FIG. 26 is a graphic illustrating the optical density of
read inhibit agents measured at a preselected wavelength consistent
with the present invention.
[0051] FIG. 27 is a graphic illustrating the absorbance of select
read inhibiting agents measured at a preselected wavelength
consistent with the present invention.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0052] Reference will now be made in detail to embodiments of the
present invention as illustrated in the accompanying drawings. The
same reference numbers may be used throughout the drawings and the
following description to refer to the same or like parts. The
following description is presented to enable any person skilled in
the art to make and use the inventive body of work. Descriptions of
specific embodiments and applications are provided only as
examples, and various modifications will be readily apparent to
those skilled in the art. For example, although many of the
examples are described in the context of certain data type
combinations any single data type may be made limited play, it
should be understood that embodiments of the present invention
could be used in any data type combinations even those combinations
not expressly stated, or the like. Similarly, although for the sake
of illustration many of the examples describe a read limiting agent
and/or mechanism in the bonding layer, those of ordinary skill in
the art will appreciate that the apparatus, devices and products of
the present invention can be applied to any suitable read limiting
agent and/or read inhibiting agent and/or reactive agent anywhere
in and/or on the optical medium. The general principles described
herein may be applied to other embodiments and applications without
departing from the spirit and scope of the invention. Thus, the
present invention is to be accorded the widest scope, encompassing
numerous alternatives, modifications, combinations and equivalents
consistent with the principles and features disclosed herein. For
purpose of clarity, details relating to technical material that is
known in the fields related to the invention have not been
described in detail so as not to unnecessarily obscure the present
invention.
[0053] The disclosure frequently makes reference to "substrates,"
"dye material," and "corrosive material." For purposes of clarity,
substrate is meant to include any structural member of an optical
medium used for support and/or to receive a subsequent layer such
as for example, a data layer, reflective layer, bonding layer,
buffer layer, lacquer layer, and additional substrate layer(s). Dye
material refers to any material that prevents the reading beam from
reading at least a portion of any data region after a predetermined
time. Corrosive material refers to any material that degrades the
integrity of at least a portion of any reflective layer and thus
prevents the reading beam from reading a portion of any data region
after a predetermined time. The disclosure uses reactive agent,
read inhibiting agent and read limiting agent interchangeably to
refer to any (either passive or active) mechanism, process,
chemical, agent that limits access to encoded information stored
and/or otherwise contained on optical media after a predetermined
time and/or after a specified event. Further, permanent play is
used interchangeably to refer to any optical media that is long
playing such that the encoded information remains accessible after
the read inhibiting agent has prevented access to selected encoded
information.
[0054] The following U.S. patents and patent applications are
hereby incorporated by reference in their entirety. U.S. Pat. Nos.
6,641,886; 6,838,144; 6,511,728; 6,537,635; 6,839,316; 6,678,239;
6,011,772; 6,343,063; 6,434,109; 6,756,103; 6,917,579; and U.S.
patent application Ser. Nos. 10/162,417; 10/016,263; 10/163,473;
10/163,855; 10/163,472; 10/651,627; 60/627,209; and 60/627,386.
HD-DVD
[0055] The HD-DVD optical media format, proposed and developed by
Toshiba and NEC and as described by the DVD Forum, consists of two
substrates bonded together as in current DVD manufacturing. At
least one of the two substrates supports encoded information. At
least one of the two substrates is optically transparent to a
reading laser. The HD-DVD format is similar to current DVD-9
design, as described by the DVD Forum (www.dvdforum.com) and ECMA
standard
(http://www.ecma-international.org/publications/standards/Ecma-267.htm),
in that up to two layers are read by a reading laser from one side
of the disc. The two data layers of the HD-DVD disc are similar to
DVD-9 construction but have narrower track pitches with smaller pit
structures. The reading laser of a HD-DVD reading device has a
wavelength of approximately 405 nm.
[0056] The present invention discloses a number of reactive agents
that can be used, either alone or in combination, with a HD-DVD
disc such that at least a portion of the encoded information on the
HD-DVD disc becomes irreversibly unreadable by the reading laser
after a predetermined time. The reactive agents contemplated by the
present invention can reside inside and/or on the surface of a
HD-DVD disc and/or in the optical path and/or outside the optical
path of the reading laser. FIG. 1 illustrates an HD-DVD limited
play embodiment 5 consistent with the invention. FIG. 1 shows two
substrates 10 and 15, wherein substrate 10 is commonly referred to
as the L0 side and as referenced through which side the optical
beam reads the encoded information. Substrate 15 is commonly
referred to as the L1 side. Reflective layers 20 and 25 are
separated by at least one intervening layer 30. In the embodiment
shown, a read inhibiting agent resides in 30, wherein the reading
inhibit agent can be one of a masking compound, such as for example
a reactive day and/or a destructive agent, such as a material that
corrodes the reflectivity of at least one reflective layer. The
encoded information is readable by an optical beam(s) 40.
[0057] The HD-DVD format uses a similar disc construct to standard
DVDs. It is therefore largely compatible with existing
manufacturing processes. Manufacturing begins with the injection
molding of two 0.6 mm thick disc substrates. Data can be molded
into one or both substrates depending on whether a single or dual
layer disc is being manufactured. The substrates with a data layer
are then metallized with either a semi-reflective and/or reflective
film and then the two substrates are bonded together. In a dual
layer product, the bonding resin is in the optical path of the
laser. For a single layer product, the bonding resin is not
normally in the optical path. As described in U.S. patent
application Ser. Nos. 10/163,473, 10/163,855, 10/163,472,
10/837,826, 10/163,821, 10/651,627 and U.S. Pat. No. 6,756,103, all
hereafter incorporated by reference in their entirety, the single
data layer can be inverted physically and moved to the L1 substrate
creating a single layer disc construct that moves the data layer so
that the laser must pass through the bonding resin, therefore
putting the bonding layer in the optical path for a single layer
HD-DVD. In this sense, the HD-DVD product is similar to DVD Formats
disclosed in U.S. patent application Ser. Nos. 10/163,473,
10/163,855, 10/163,472, 10/837,826, 10/163,821, 10/651,627 and U.S.
Pat. No. 6,756,103, all hereafter incorporated by reference in
their entirety) and DVD-9 product. The differences lie in the
reading laser wavelength as described above. This enables higher
data density through a tighter track pitch and smaller pit sizes,
raising storage capacity from 4.7 Gbytes as available on a standard
DVD-5 to 15 Gbytes on a single layer HD-DVD.
Blu-Ray
[0058] The Blu-ray optical format, proposed and developed by a
number of companies and lead by Sony, includes of a single
substrate. The substrate of a Blu-ray disc does not need to be
optically transparent to the reading laser because the data is read
through a cover layer approximately 0.1 mm thick. This cover layer
is in the optical path of the reading laser and is either bonded to
the substrate and/or spin coated in one or more layers on the
substrate. The reactive agents and/or read inhibiting agents and/or
read limiting agents contemplated by the present can be used,
either alone or in combination, with a Blu-ray disc such that at
least a portion of the encoded information on the Blu-ray disc
becomes irreversibly unreadable by the reading laser after a
predetermined time. The reactive agents contemplated by the present
invention can reside inside and/or on the surface of a Blu-ray disc
and/or in the optical path and/or outside the optical path of the
reading laser.
[0059] In one embodiment consistent with the invention, a reactive
dye is integrated into any of the cover layers that form the
optical path of the Blu-ray disc and blocks the read laser from
reading the encoded information after the reactive dye is exposed
to a stimulus. FIG. 2 illustrates a limited play Blu-ray embodiment
105 consistent with the invention. FIG. 2 shows a substrate 130
supporting encoded information 140 with a reflective layer 120 a
bonding layer 125 with a cover layer 115 and a hard coat 110. The
read inhibiting agent can reside in at least one of the bonding
layer 125, the cover layer 115, and a hard coat 110. The encoded
information 140 is readable by an optical beam 135. In the
embodiment shown the reading inhibit agent can be one of a masking
compound, such as for example a reactive day and/or a destructive
agent, such as a material that corrodes the reflectivity of at
least one reflective layer.
[0060] FIG. 3 illustrates a limited play Blu-ray embodiment 105
consistent with the invention without a hard coat 110. In the
embodiment shown the reading inhibit agent can be one of a masking
compound, such as for example a reactive day and/or a destructive
agent, such as a material that corrodes the reflectivity of at
least one reflective layer and resides in one of the bonding layer
125 and cover layer 115.
[0061] Blu-ray discs use a different manufacturing approach than
that used for standard DVDs and HD-DVDs. In Blu-ray discs, the disc
substrate is removed from the optical path, which eliminates issues
related to stress induced birefringence of the molded substrate. A
second reason the disc substrate is removed from the optical path
of the reading laser is that is reduces the disc tilt at the read
surface. Disc tilt occurs when the surface of the disc is not
perpendicular to the read laser. A system with a higher numerical
aperture (NA) lens is more sensitive to disc tilt. In Blu-ray, the
numerical aperture is increased from 0.6 mm in standard DVD NA, to
0.85 mm. The recording layer and/or data storage layer of a Blu-ray
disc is placed on the surface of a 1.1 mm substrate, protected by a
0.1 mm cover layer. The cover layer is in the optical path and is
much thinner than the standard DVD L0 layer and HD-DVD 0.6 mm
substrate. The 0.85 NA enables the use of the high numerical
aperture lens at the 405 nm wavelength as the read optics can be
closer to the data layer. Substrate birefringence is eliminated,
and surface tilt issues reduced. However, new problems are
introduced that require the cover layer to be manufactured
according to very stringent specifications, and surface defects
such as scratches or fingerprints are a much more significant issue
than in standard DVD and HD-DVD formats. Hard coatings with the
ability to be wiped or cleaned without scratching are being
developed by the Blu-ray group, which is lead by Sony. These hard
coatings are also in the optical path and are typically spin coated
onto the surface of the cover layer.
[0062] According to one embodiment consistent with the invention, a
limited play Blu-ray disc is disclosed. The limited play Blu-ray
disc incorporates dye absorption technology, i.e., a reactive
material and/or read inhibiting agent and/or read limiting agent,
in the optical path. The reactive material responds to a stimulus
thereby converting from a substantially transparent state at the
405 nm wavelength to a substantially opaque state that inhibits the
reading of at least a portion of the data layer by the read laser.
Dyes selected from those disclosed herein can be integrated into
the 0.1 mm cover layer and/or surface coating of the Blu-ray disc.
This puts the reactive material in the optical path of the reading
laser. This methodology applies to both single and dual layer
Blu-ray discs.
[0063] A reactive dye can be incorporated into any or all layers
within the optical path including the bonding layer, 100 micron
cover material and/or hard coat layer. A corrosive agent can be
contiguous with the reflective layer and may incorporate the
bonding and cover layer, which could also serve as a hard surface
coat.
CD
[0064] In one embodiment consistent with the invention a compact
disc (hereafter "CD") includes a mechanism, chemical, agent and/or
process for limiting the period of time encoded information stored
on the CD can be read and/or accessed. The mechanism, chemical,
agent and/or process for limiting the access time can be applied to
CDs that have the encoded information encoded during the
manufacturing process (i.e., CD-Read Only Memory, hereafter
"CD-ROM") and/or encoded information encoded by recording directly
onto the CD (i.e., CD-Recordable and/or CD-Rewritable and the
like). Further, the mechanism, chemical, agent and/or process for
limiting the access time is independent of the type and/or kind of
data and/or information encoded on the CD (i.e., audio, video,
data, software, images, text, games, combinations thereof, etc.).
CD standards, put forth by industry groups such as ECMA
International, describe the technical and manufacturing aspects of
the various CD formats, i.e., CD-Audio, CD-ROM CD-Recordable,
CD-Rewritable, CD-Interactive, CD-Video.
[0065] The various available CD formats generally adhere to a disc
structure based on a 1.2 mm thick molded substrate with a data
layer on the top surface coated with a reflective layer. The data
layer is read from the bottom side of the substrate by a 720 nm
laser.
[0066] In one embodiment consistent with the invention a limited
play optical CD can be constructed using a corrosive material layer
adjacent to the reflective layer. The corrosive agent responds to a
stimulus and/or triggering event, such as for example, exposure to
oxygen, which causes the corrosive agent to react with the
reflective layer such that the associated data layer, or a portion
thereof, is no longer readable by the read laser of the reading
device.
[0067] In another embodiment consistent with the invention a 1.2 mm
thick optically transparent substrate is constructed with multiple
layers, at least two, of molded substrates. Two 0.6 mm thick
substrates are bonded together using a reactive dye material to
form a 1.2 mm thick substrate. However, it should be noted that two
halves and/or substrates of equal thickness are not required, for
example, one substrate could be 0.4 mm thick and the other 0.8 mm
thick and variations thereof. Moreover, the total overall thickness
of 1.2 mm is used here, as an exemplary embodiment and to comply
with the specifications set forth by ECMA, ISO, and the DVD Forum
so that discs will play in a large percentage of the players
currently in the homes of consumers. However, as the standards
bodies change the specifications so too the embodiments consistent
with the invention and disclosed herein can be changed and still
meet the metes and bounds of the present invention. This statement
also applies for CD, DVD, High Definition, Blu-ray, and other next
generation optical media. The disclosed specific dimensions herein
are made to provide examples of limited play optical media
consistent with the invention and to maximize playability in the
current install base of current CD and DVD readers and
recorders.
[0068] FIG. 4 illustrates an embodiment consistent with the
invention showing a CD and DVD optical medium 205. The bottom
substrate 210, or L0 substrate as it is referred to in a DVD
construct, would be a blank disc with no data structures molded on
either surface of the L0 substrate. The second substrate 225, or L1
substrate, is molded with a CD data layer or recordable structures
220 on the top surface. The surface is then coated with a
reflective layer or recordable layers 230 to complete the disc
according to its format specifications and as specified by disc
standards bodies such as, for example, ECMA and ISO. The reflective
layer or recordable layers 230 are covered by a protective layer
240. The bottom of the L1 substrate 225 is molded with a DVD data
layer or recordable structures 215. The DVD data layer 215 and the
CD data layer 220 are readable by optical beams 245 and 250,
respectively. The reactive dye in the bonding layer 235, when
exposed to a stimulus and/or triggering event, such as for example
exposure to oxygen, will disable the ability of the laser to read
and/or record data from the disc.
[0069] The above embodiments do not require that the limited play
mechanism, for example, corrosive agent and/or reactive dye, be an
entire layer or be throughout a single layer and either can be
present in limited regions of the media. For example, the limited
play mechanism can be localized to a region and/or regions that
prevent the entire encoded information stored on the media from
being read by the reading beam. Alternatively, the regions with the
localized mechanism will be the regions associated with the limited
play mechanism.
CD Hybrids
[0070] In yet another embodiment consistent with the invention an
optical media that includes at least two different types of data
structures and/or data formats and at least one mechanism,
chemical, agent and/or process for limiting access to the data
region of either type of data structure and/or data format, all the
types of data structures and/or data formats contained on the
optical media, and/or portions thereof is described. This
embodiment includes, for example, combinations of at least two data
structures and/or data formats selected from Read Only Memory
(ROM), Write Once, Read Many (WORM), Interactive (I), Erasable (E),
CD-ROM, CD-WORM, CD-I, DVI, CD-EMO, OD3, ODD, Video Disk, IVD,
Blu-ray, HD-DVD, DVD, DVD-R, DVD-Video, DVD-RAM, DVD-Audio,
DVD-RAM, DVD-RW, DVD+RW, DVD+R, DVD-Video, SACD, variants of the
above, and/or any data structure and/or data format that is
readable by an optical beam and/or optical reading device,
including holographic, holographic versatile discs and 3-D optical
storage devices. In this embodiment, the at least two data
structures and/or data formats may be accessed by the reading
beam(s) through the same substrate layer and/or substrate side,
i.e., without physically flipping the disc over; each through a
unique substrate layer and/or substrate side, i.e., physically
flipping the disc over to access the data of the other type; or a
combination thereof. In an overlapping embodiment consistent with
the invention at least one data structure and/or data format may be
accessed by the reading beam(s) through the same substrate layer
and/or substrate side, i.e., without physically flipping the disc
over; each through a unique substrate layer and/or substrate side,
i.e., physically flipping the disc over to access the data of the
other type; or a combination thereof.
Recordable Format
[0071] In still another embodiment consistent with the invention an
optical media includes a mechanism for recording information and
storing it on the optical media and a mechanism, chemical, agent
and/or process for limiting the period of time the recorded
information is accessible. The data format recorded is not limited
to CD, DVD, High Definition, Blu-ray, 3-D, and/or holographic data
formats and includes any recordable data format.
CD/DVD Hybrid
[0072] The present invention includes a number of optical media
embodiments that employ at least one reactive agent and/or material
to limit access to encoded information stored thereon. The
disclosed embodiments of the present invention can be configured to
limit either partial or full access to the encoded information,
i.e., only a portion of the encoded information will remain
permanently accessible or the entire encoded information will
become inaccessible after a predetermined period. The disclosed
embodiments include read only and/or recordable configuration. The
disc embodiments can employ a reactive agent that masks the encoded
information, i.e., dye compounds that absorb the wavelength of the
reading beam, and/or read inhibiting agent(s) that erodes,
corrodes, destroys the integrity of the reflective layer, and/or
destroys the integrity of a substrate material after a
predetermined time. The reactive agent and/or material can be in
the optical path of the reading beam and/or outside the path of the
optical reading beam. In addition, limited play characteristics are
disclosed in the present invention that combine recordable media
layers, which allow limited access to pre-recorded media, with
recordable media layer(s) that retain the ability to record
permanent data to the optical disc after the pre-recorded media is
no longer accessible. These embodiments include the combinations of
a limited play DVD with long playing DVD or CD recordable
layers.
[0073] There exists a need for an optical medium that provides both
long life content and limited life content because content owners
desire a platform in which to conveniently and inexpensively rent
their content to consumers while minimizing waste. The dual life
optical medium disclosed in at least one of the embodiments of the
present invention provides the consumer the necessary incentive to
keep the optical medium long after the limited life content has
expired.
[0074] FIG. 5 illustrates an embodiment consistent with the present
invention. This embodiment provides an optical medium 305 that
contains encoded information with two separate life times. The L0
side 310 includes encoded information 320 that is the limited life
side. After a predetermined time the encoded information 320 on
this side becomes irreversibly inaccessible. The L1 side 315
includes encoded information 325 that is the long life side. After
the L0 side 310 encoded information 320 is not longer accessible
the L1 315 encoded information 325 will remain accessible. This
construct can use either a masking dye and/or corrosion agent,
which resides in the bonding layer 335. If a corrosion agent is
employed it eliminates the L0 silver semi-reflective layer 330 and
thus removes the reflected signal from that layer. To prevent the
thicker silver layer from being affected an alternative reflective
material can be substituted for the silver in this layer. The top
of the L1 side 315 includes encoded information 325, a reflective
layer 340, and a protective layer 345. The encoded information 320
and 325 is read by optical beams 350 and 355, respectively.
[0075] These embodiments provide optical media that contains
encoded information with two separate life times, a limited life
and an indefinite life. In these embodiments the encoded
information is read for both DVD and CD from one side. Both
metallic and dielectric semi-reflective layers can be used.
Metallic semi-reflective films have an effect on the reading of the
780 nm laser used to read the CD layer. In thinner films, the read
signal is still acceptable. Dielectric films can be used as the
semi-reflective layer. Dielectric films are transparent at 780 nm
and reflective at 650 nm. A combination of semi-reflective films
may also be used to form a layered semi-reflective film with the
corrosive sensitive region of the layer facing the bonding
material. Signals for the CD reading laser are improved in this
construct but are not always necessary. This construct uses
corrosion chemistry with the bonding layer. The corrosion chemistry
will eliminate the L0 silver semi-reflective layer and remove that
reflected signal from that layer. The thicker full reflective
layers bulk properties are designed not to be affected by the
corrosion chemistry. This can be accomplished either by the bulk
properties of materials (thick film vs. very thin) similar to the
semi-reflective film or by changing the full reflective layer to a
different material such as Au, or silver alloy that does not get
impacted by the corrosion mechanism. With a dye that is transparent
at the CD 780 nm wavelength but absorptive at the DVD wavelength
the DVD will be blocked while the CD will play.
[0076] In embodiments consistent with the invention limited play
media constructs with modified disc thicknesses are disclosed. In
this embodiment a thin CD is placed back to back with a thin DVD.
The CD, DVD, portions of either and/or both, or both disc types
include a limited play mechanism, such as for example, a dye in the
optical path and/or corrosion of the reflective layer or portions
thereof. As described above, the CD substrate can be, for example,
an audio, ROM, recordable, or rewritable disc while the DVD side
can be, for example, a DVD-5, an inverse DVD-5, DVD-9,
DVD-Recordable, or DVD-Rewritable. These two substrates with
associated data structures, recording layers, and appropriate
reflective layers can be combined together in any combination.
[0077] In yet another embodiment consistent with the invention a CD
data layer and a DVD data layer use two substrates bonded together
and are read from one substrate side.
[0078] In still another embodiment consistent with the invention an
optical medium includes encoded information with two separate life
times, a limited life and an indefinite life. In this embodiment
the medium is played and/or read, for both DVD and CD, from one
substrate side. The reflective layers can be selected from metallic
films, dielectric semi-reflective films, metallic semi-reflective
films, dielectric films, and/or combinations thereof.
[0079] Metallic semi-reflective films have an effect on the reading
of the 780 nm laser used to read the CD layer. Dielectric films can
be made which are transparent at 780 nm and reflective at 650 nm. A
combination of semi-reflective films may also be used to form a
layered semi-reflective film. A mechanism for limited the time a
reflective layer and/or semi-reflective layer can be read by a
reading beam and/or for limiting the integrity of a reflective
layer and/or semi-reflective layer with the inclusion of a dye,
corrosive material and/or other reading limiting agent in the
optical path and/or adjacent to a reflective layer and/or
semi-reflective layer. For example, in one embodiment consistent
with the invention wherein the CD data layer and DVD data layer are
read from one substrate side a corrosive material eliminates the L0
semi-reflective layer and removes that reflected signal from that
layer after a predefined period of time.
CD/DVD with Semi-Reflective Layer on DVD-5.
[0080] A variant of the above embodiments is to make the DVD
portion an inverse DVD-5 as disclosed in U.S. patent application
Ser. Nos. 10/163,473, 10/163,855, 10/163,472, 10/837,826,
10/163,821, 10/651,627 and U.S. Pat. No. 6,756,103, all hereafter
incorporated by reference in their entirety. The L1 side has CD
data structures on the top side, and DVD data structures on the
bottom of the same disc half (data structures on both sides of the
top disc half, i.e., L1 side). This embodiment enables the use of
bonding resins based on either corrosion chemistry as in the two
examples above or reactive dye chemistry as the bonding layer is
located within the optical path. Both metallic and dielectric
semi-reflective layers can be used. Metallic semi-reflective films
do have an effect on the reading of the 780 nm laser used for the
CD layer. In thinner films, the read signal is still acceptable.
Dielectric films such as silicon, silicon oxides, or silicon
nitrides can be used as the semi-reflective layer which are
transparent at 780 nm and reflective at 650 nm. Using reactive dye
chemistry, dielectric films do not need to be eroded with a
corrosion effect so that they can be optimized for their optical
properties. This provides signals for the CD layer that meet all
specifications and provide a wider processing window.
Two Discs Bonded Together
[0081] Another embodiment consistent with the invention provides an
optical medium that contains encoded information with two separate
life times, a limited life and an indefinite life. In this
embodiment, disc thickness is kept below 1.5 mm which means the two
disc halves are manufactured below the lower disc specifications on
disc thickness and as specified by the DVD Forum and ECMA. For
example, a DVD disc half would normally be manufactured at 0.6 mm
and a CD substrate at 1.2 mm. Combining the two would create a disc
thickness in excess of 1.8 mm when bonded together back to back. By
reducing the two substrates to just below minimum thickness
specifications, it is possible to achieve a disc thickness below
1.5 mm. while still maintaining playability in an estimated 98% of
players. Two graphics are shown with the first showing a CD with
protective lacquer over the metal layer before bonding, the second
without the lacquer as it is replaced by the bonding material. In
this example the limited play mechanism uses the corrosion
chemistry to erode the semi-reflective film as described earlier in
the text. The first illustration shows a CD with a protective
lacquer over the metal layer before bonding, the second
illustration shows a CD without the lacquer as it is replaced by
the bonding material.
[0082] FIG. 6 illustrates another embodiment consistent with the
invention. A hybrid optical medium 405 containing two optically
readable formats wherein the format residing on the L0 side 410 is
of limited life. Each format is readably via optical beams 450 and
440 through its own substrate side. In this illustration the CD
format is read through the L1 side 415. A reflective layer 420
resides at the bottom of the L1 side 415. A protective layer 425
separates the reflective layer 420 from the L0 side 410. The L0
side 410 contains the DVD format. At the top of the L0 side 410 is
a reflective layer 435. An adhesive layer 430 separates the L0 side
410 from the L1 side 415. A read inhibiting agent resides in the
adhesive layer 430.
[0083] FIG. 7 illustrates another embodiment consistent with the
invention. A hybrid optical medium 505 containing two optically
readable formats wherein at least one of the formats is of limited
life. Each format is readably via optical beams 535 and 540 through
its own substrate side. In this illustration the CD format is read
through the L1 side 530. A reflective layer 525 resides at the
bottom of the L1 side 530. The L0 side 510 contains the DVD format.
At the top of the L0 side 510 is a reflective layer 515. An
adhesive layer 520 separates the reflective layer 525 on the L1
side 530 from the reflective layer 515 on L0 side 510. A read
inhibiting agent resides in the adhesive layer 520. The read
inhibiting agent makes at least one of the two formats unreadable
and/or inaccessible after a predefined period of time and/or
event.
[0084] In another embodiment consistent with the invention,
thicker, full reflective layers are not affected by the corrosive
material. This can be accomplished either by the bulk properties of
materials (thick film vs. very thin) similar to the semi-reflective
film or by changing the full reflective layer to a different
material such as Au, or silver alloy that does not get impacted by
the corrosion mechanism. Thus, providing an optically readable
medium with two time scales of accessibility.
[0085] In an overlapping embodiment consistent with the invention a
bonding resin is in the optical path of the CD read laser. With a
dielectric reflective layer on L0, the CD laser is not blocked by
this first reflective layer. The CD laser then reads the L1 data
through the bonding resin that includes a reactive dye material
that absorbs the read laser after a predetermined period of time.
In this embodiment the CD data is of limited duration and/or
limited accessibility. Alternatively, the semi-reflective L0 layer
is bonded with a material that results in corrosion of the L0
reflective layer after a predefined period of time. This
configuration degrades the DVD reflective layer and creates a
limited play DVD layer with a CD that is permanent play.
[0086] An overlapping embodiment of the above the DVD portion is
made using an inverse DVD-5 as disclosed in U.S. patent application
Ser. Nos. 10/163,473, 10/163,855, 10/163,472, 10/837,826,
10/163,821, 10/651,627 and U.S. Pat. No. 6,756,103, all hereafter
incorporated by reference in their entirety. In this embodiment,
the L1 disc has CD data structures on the top side, and DVD data
structures on the bottom of the same disc half (data structures on
both sides of the top disc half). This embodiment enables the use
of bonding resins based on either corrosive materials as in the
examples above or dye materials as the bonding layer is located
within the optical path of the reading beam(s). Both metallic and
dielectric semi-reflective layers can be used. Metallic
semi-reflective films do have an effect on the reading of the 780
nm laser used for the CD layer. In thinner films, the read signal
is still acceptable. Dielectric films such as silicon, silicon
oxides, or silicon nitrides can be used as the semi-reflective
layer, which are transparent at 780 nm and reflective at 650 nm.
Using dye materials, dielectric films do not need to be eroded with
a corrosive material so that they can be optimized for their
optical properties. This provides signals for the CD layer that
meet all ECMA, DVD Forum and ISO specifications and provide a wider
processing window.
[0087] In another embodiment consistent with the invention an
optical medium includes encoded information with two separate discs
bonded back to back. In this embodiment, disc thickness is kept
approximately in the range of 1.5 mm or lower to keep the overall
disc thickness within the ranges specified by ECMA and/or ISO.
However, as specifications of ECMA and ISO change so to can the
disc thickness and be consistent with the invention. In this
embodiment the two disc halves are manufactured below the lower
disc specifications on disc thickness and as specified by the DVD
Forum and ECMA. For example, a standard long playing DVD disc half
is currently manufactured at a thickness of 0.6 mm and a CD
substrate at 1.2 mm. Combining the two formats into a single disc
without modification would create a disc thickness in excess of 1.8
mm when bonded together back to back. By reducing the two
substrates to just below minimum thickness specifications, it is
possible to achieve a disc thickness below 1.5 mm while still
maintaining playability in an estimated 98% of players currently on
the market. FIG. 5 shows a CD with protective lacquer over the
metal layer before bonding. FIG. 6 shows the discs bonded without
the lacquer layer as it is replaced by the bonding material. In
this example the limited play mechanism uses a corrosive material
to erode the semi-reflective film.
DVD-9 Bonded to a CD
[0088] Using a peel technique in the construction of the L1
substrate to make a DVD-9 disc half, a limited play DVD-9 can be
bonded back to back with a CD to make a further embodiment
consistent with the invention of a limited play DVD combined with a
permanent play CD format substrate. FIG. 8 illustrates a dual layer
DVD format bonded to a recordable CD format consistent with the
present invention. An L1 side 615 contains two DVD data layers 660,
similar to a DVD-9, with two reflective layers 620 and 630 at the
top of the L1 side 615 bonded 635 to an L0 side 610. Separating the
two DVD data layers is an intervening layer 625, wherein a read
inhibiting agent resides. The L0 side 610 contains a recordable CD
format including a reflective layer 640 and a recordable material
645. At least one of the DVD format layers is of limited life. The
CD format and DVD format are read through their respective L0 and
L1 sides via optical reading beams 650 and 655. The L0 disc half is
molded thinner than ECMA, ISO, DVD Forum specifications to keep
total disc thickness below 1.5 mm. Since the disc is flipped to be
read from each side, the reflective layers are optimized for each
side, CD and DVD. This DVD-9 limited play disc half is then bonded
to either a permanent play or recordable CD, again molded with a
thinner substrate.
DVD Formats
[0089] These embodiments provide an optical medium that contains
encoded information with two separate life times. In one embodiment
the L0 encoded information is the limited life side. After a
predetermined time the encoded information on this side becomes
irreversibly inaccessible. The L1 encoded information is the long
life side. After the L0 encoded information is no longer accessible
the L1 encoded information will remain accessible. The corrosion
agent eliminates the L0 silver reflective layer and thus removes
the reflected signal from that layer. To prevent the L1 reflective
layer from being affected by the same mechanism, it can be made
thicker and/or an alternative reflective material can be
substituted in this layer.
EXAMPLE
[0090] DVD-10 discs were made using an L0 reflective layer which
was varied in thickness and corresponding reflectivity. It was
determined that a great majority of consumer players will play a
DVD-5 disc half at much lower reflectivities than DVD ECMA, DVD
Forum and/or ISO specifications. To create a limited play optical
media, the reflective film was reduced in reflectivity to that of
an equivalent layer used in DVD-9 manufacturing of the L0 layer.
This reflectivity ranges from 18 to 30%. Discs were also made at
reflectivities increasing until the DVD specification (as defined
by ECMA, ISO and DVD Forum) of 45% was reached. This reflective
layer is susceptible to corrosion effects. By varying the thickness
of the reflective layer, one can also effect the play time of the
media. Playability was acceptable in our testing with a range of
consumer players such as the Pioneer DV-563A, JVC XV-N50, and
Panasonic DVD S-25.
[0091] When the L0 reflective layer was increased until DVD-5
specifications (as defined by ECMA, ISO, and DVD Forum) were met
with a minimum reflectivity of 45%, the L0 reflective layer can
still be produced with significantly less thickness than the L1
layer. This allows the L1 to be made with the same material but
still maintain its reflective properties for permanent play. As
mentioned previously, the L1 layer can also be made with alternate
reflective materials such as gold (Au) which would not react to
degrade the reflectivity of the layer with the read limiting
mechanism, rendering one side of the disc playable after one side
has failed to play.
DVD-9 with One Recordable Layer
[0092] In another embodiment consistent with the present invention
a limited play disc with a recordable layer is described. A read
limiting agent is integrated within a bonding adhesive, which is
used to bond two substrates together. The L1 disc half is bonded
using an adhesive containing a read limiting agent to a L0
substrate with a recordable dye coated on a grooved surface as
specified in recordable formats by the various standards bodies. A
disc is provided with a limited play L1 data layer and a recordable
L0 layer that will play after the L1 data has become unreadable.
Using authoring techniques the entire L0 layer or a part of it can
also be defined as a limited play area. Further, the limited
mechanism, does not have to be an entire layer or through out the
disc and instead may be localized to a select region(s), such
localization may, depending on the configuration, prevent access to
all the data on a particular layer or selection regions only. The
L0 layer could then still be recordable. The disc is authored so
that when inserted into a player, the L1 would be recognized as
having been recorded and the L0 available for recording.
[0093] FIG. 9 illustrates a DVD-9 with a recordable DVD layer
consistent with the invention, wherein at least one layer of the
DVD-9 side is of a limited life. An optical medium 705 is formed by
bonding two substrates 715 and 710 together. The L1 substrate 715
contains two reflective layers 720 and 730 separated by an
intervening layer 725 at the bottom of the L1 substrate 715. The L0
substrate contains a reflective layer 740 and a recording material
745 for recording encoded information. The L0 substrate 715 and L1
substrate are joined together by a bonding and/or adhesive layer
735. The read inhibiting agent resides in at least one of the
intervening layer 725 and the bonding layer 735.
DVD-R/DVD-5 Limited Play Disc
[0094] In yet another embodiment consistent with the invention a
disc is constructed using a DVD-R bonded to a DVD-5. One side plays
the DVD-5 content, for example, movie or video content. Once
flipped over a single layer DVD-R is available for recording data.
The bonding resin employs a material that corrodes the reflective
DVD-5 film without attacking the reflective layer of the recordable
side.
[0095] FIG. 10 illustrates an embodiment consistent with the
invention, wherein an optical medium 805 with a recordable layer
and limited play layer are combined. The recordable layer and the
limited play layer are read through their own unique substrates. As
illustrated, the L0 substrate 810 contains the recordable layer,
wherein the top of the L0 substrate 810 includes a reflective layer
830 and a recording material 835. The L0 substrate 810 is bonded to
the L1 substrate 815 via a bonding and/or adhesive layer 835. The
L1 substrate 815 contains the limited play data layer. The bottom
of the L1 substrate 810 includes a reflective layer 820. The
reading inhibiting agent resides in the bonding layer 835 and
allows for the L1 substrate 815 data layer to be of limited life
while allowing the recordable layer to be long playing. The data
layers are read by optical beams 840.
[0096] FIG. 11 illustrates an embodiment consistent with the
invention, wherein an optical medium 905 with a recordable layer
and limited play layer are combined. The recordable layer and the
limited play layer are read through same substrate side. As
illustrated, the L0 substrate 935 contains the recordable layer,
wherein the top of the L0 substrate 935 includes a reflective layer
925 and a recording material 930. The L0 substrate 935 is bonded to
the L1 substrate 910 via a bonding and/or adhesive layer 920. The
L1 substrate 910 contains the limited play data layer. The bottom
of the L1 substrate includes a reflective layer 915. The reading
inhibiting agent resides in the bonding layer 920 and allows for
the L1 substrate 910 data layer to be of limited life while
allowing the recordable layer to be long playing. The data layers
are read by optical beams 940.
DVD 14/18 Constructs
[0097] Using existing dye technology, and as disclosed in the above
referenced U.S. patents and applications, DVD 14 discs can be
manufactured which combine a limited play DVD-9 with a permanent
play DVD-5 layer. In this embodiment the limited play techniques
disclosed to make DVD-9 product including partial dispense and
authoring techniques. Once the DVD-9 is manufactured, the top
substrate is mechanically peeled away as in a standard DVD-14
process, and a new top substrate bonded to the disc. This new
substrate can be either a permanent play DVD-5, a second permanent
play peeled DVD-9 half, limited play peeled DVD-9 half, or a
recordable DVD-5 half or dual layer recordable DVD disc half. In
this way several combinations of disc halves can be combined using
recordable, permanent play, or limited play disc halves. For
example, a limited play DVD-9 bonded to a permanent play DVD-5 can
be read by flipping the disc over. A DVD-9 limited play disc half
bonded to a single layer recordable DVD disc half that must be
recorded by flipping the disc over. In this way disc capacities can
be increased, recordable layers combined with limited play data
regions, and permanent play areas extended to entire layers. This
provides significant flexibility to address many applications of
permanent play, limited play, and recordable applications.
[0098] FIG. 12 illustrates an embodiment consistent with the
invention. An optical medium 1000 includes a DVD-9 format bonded to
a DVD-5 format. At least one layer or portion thereof can be of
limited life. The L1 substrate 1010 includes a DVD-5 format with a
reflective layer 1015 at the bottom of the L1 substrate 1010. The
L1 substrate 1010 is bonded to the L0 substrate 1005 via a bonding
and/or adhesive layer 1035. The L0 substrate 1005 includes a DVD-9
format at its top, with two reflective layers 1020 and 1025
separated by an intervening layer 1030. The DVD-9 and DVD-5 formats
are read through their own substrates by optical beams 1040. At
least one encoded information layer or a portion thereof is of
limited life.
HD-DVD Formats
[0099] It is clear from the discussion and depiction of various
constructs above that many different forms or combinations of
optical disc formats can be combined with limited play technology.
This also applies to bringing together various high density disc
formats with conventional DVD formats, or even combining both
proposed high density formats, HD-DVD and Blu-ray, on a single
disc. The following embodiments consistent with the invention
combine limited play and/or conventional HD-DVD and/or Blu-ray data
layers with limited play and/or conventional DVD layers. The
Blu-ray and HD-DVD limited play constructs have been discussed
above. In a further embodiment, all data layers could be limited
play or conventional permanent data layers. These constructs
provide a large matrix of possibilities combining formats with and
without limited play access to either all or selected sections of
the encoded information on a data layer.
[0100] Limited play optical media can be produced incorporating
reactive materials in the disc substrate, bonding layer, coatings
within the structure of the disc and/or layered on the surface of
the disc. A long playing Digital Versatile Disc (DVD) is normally
constructed with the bonding of two 0.6 mm substrates. The current
proposed specifications for Blu-ray and HD-DVD discs differ in
their data layer location and disc construction. Blu-ray and HD-DVD
data layers can be combined in one disc using reactive materials
that can be incorporated into the construct of the disc which can
eliminate the playability of all or part of the stored data on the
disc. Because these discs are still constructed from layered
substrates, novel constructs can be created which were not
anticipated by those who developed the high definition video disc
specifications for both Blu-ray and HD-DVD. In particular, the
combination of both formats into a single disc with and without
limited play data layers is envisioned. Additionally, selected
layers can also include recordable functionality.
HD-DVD and DVD 5/9/Recordable Data Layers
[0101] In the HD-DVD specification set forth by the DVD Forum, the
product essentially uses two 0.6 mm substrates bonded together much
in the same way as standard DVD. In an embodiment consistent with
the invention, standard DVD data layers, both permanent and limited
play are combined together with HD-DVD data layers, both permanent
and limited play. For single layer HD-DVD and single layer DVD
combinations, the two disc substrates are simply bonded together
giving a DVD 5 or single layer DVD-R played or recorded from one
side and a single layer HD-DVD or recordable HD-DVD played or
recorded from the other. Either substrate could also have a second
data layer added through standard DVD-14/18 bonding stripping
techniques, or recordable layers added through standard dual layer
recordable manufacturing processes. FIG. 13 below illustrates two
dual layer substrates bonded together to form an HD-DVD dual layer
disc combined with a DVD-9. Any of the data layers can be made
limited play through the addition of reactive materials into the
bonding resin, reflective layers, and/or substrates of the disc.
The limited play capability could limit access to a part of any
data layer or all of the data stored on the disc.
[0102] FIG. 13 illustrates an embodiment consistent with the
present invention. The L1 substrate 1105 includes an HD-DVD data
format. The L1 substrate 1105 is bonded via a bonding layer and/or
adhesive layer 1140 to an L0 substrate 1110. The L0 substrate 1110
includes a DVD-9 data format. The bottom of the L1 substrate 1105
includes two reflective layers 1115 and 1120 separated by an
intervening layer 1145. The top of the L0 substrate 1110 includes
two reflective layers 1125 and 1130 separated by an intervening
layer 1135. The HD-DVD and DVD-9 formats are read through their own
substrates sides via optical beams 1150 and 1155, respectively. A
read inhibiting agent limits the life of at least the HD-DVD and
DVD-9 format. The read inhibiting agent resides in at least one of
intervening layer 1145, bonding layer 1140, and intervening layer
1135.
Blu-Ray and DVD 9/5/Recordable Hybrid Disc
[0103] As described above, the Blue-ray disc is constructed with a
1.1 mm substrate that is not in the optical path. Therefore it is
possible to create that substrate using two substrate layers bonded
together. Instead of molding substrates with HD-DVD layers, it is
also possible to use standard DVD data layers including DVD-5,
DVD-9, and single or dual layer recordable data layers within the
1.1 mm substrate of the Blu-ray disc an example of which is shown
in FIG. 14. This embodiment combines limited play capability to a
part and/or all of the data stored and/or recorded onto the disc or
any of its data layers.
[0104] FIG. 14 illustrates an embodiment consistent with the
present invention. The L1 substrate 1205 includes an Blu-ray data
format. The L1 substrate 1205 is bonded via a bonding layer and/or
adhesive layer 1240 to an L0 substrate 1210. The L0 substrate 1210
includes a DVD-9 data format. The top of the L1 substrate 1205
includes two reflective layers 1215 and 1220 separated by an
intervening layer 1245. The L1 substrate 1205 further includes a
bonding layer 1212 and a cover layer 1214. The top of the L0
substrate 1210 includes two reflective layers 1225 and 1230
separated by an intervening layer 1235. The Blu-ray and DVD-9
formats are read through their own substrates sides via optical
beams 1250 and 1255, respectively. A read inhibiting agent limits
the life of at least the Blu-ray and DVD-9 format and/or a portion
thereof. The read inhibiting agent resides in at least one of
intervening layer 1245, bonding layer 1240, intervening layer 1235,
the bonding layer 1212, and the cover layer 1214.
[0105] To achieve a dual layer DVD-9 using the above construct, a
mold, bond, and strip process and/or peel process is typically used
to form the second layer as in DVD-14/18 manufacturing processes.
This could be eliminated if data layers were molded on both sides
of the top substrate as shown below in FIG. 15.
[0106] FIG. 15 illustrates an embodiment consistent with the
present invention. The L1 substrate 1305 includes a Blu-ray data
format. The L1 substrate 1305 is bonded via a bonding layer and/or
adhesive layer 1335 to an L0 substrate 1310. The L0 substrate 1310
includes a DVD-9 data format. The top of the L1 substrate 1305
includes two reflective layers 1315 and 1320 separated by an
intervening bonding layer 1335. The L1 substrate 1305 further
includes a cover layer 1314. The top of the L0 substrate 1310
includes two reflective layers 1325 and 1330 separated by an
intervening layer 1335. The Blu-ray and DVD-9 formats are read
through their own substrates sides via optical beams 1350 and 1355,
respectively. A read inhibiting agent limits the life of at least
the Blu-ray and DVD-9 format and/or a portion thereof. The read
inhibiting agent resides in at least one of bonding layer 1335,
intervening layer 1315, and the cover layer 1314.
Hybrid HD-DVD and Blu-Ray Disc
[0107] In another embodiment consistent with the invention both
optical disc formats (for example HD-DVD and/or DVD and Blu-Ray)
are combined into one disc as shown in FIG. 16. A Blue-ray
substrate is 1.1 mm thick and is not in the optical path of the
laser. The data layer is on the top surface and bonded to a cover
layer through a variety of techniques including a spincoated layer,
and/or bonding a thin 0.1 mm cover layer, and/or bonding/adhering a
film layer to the disc to form the cover layer. Since the 1.1 mm
substrate is not in the optical path of a Blu-ray disc player, that
substrate could be two layers bonded together as in DVD or HD-DVD
manufacturing. The first layer would be 0.6 mm thick while the
second would be 0.5 mm. The bonding layer could be a nominal 55
microns thick for DVD or thinner for the HD-DVD bonding layer. The
second disc substrate thickness would be adjusted accordingly
depending on the bonding layer thickness. When bonded the total
substrate thickness would meet the 1.1 mm Blu-ray substrate
specification.
[0108] FIG. 16 illustrates an embodiment consistent with the
present invention. The L1 substrate 1405 includes a Blu-ray data
format. The L1 substrate 1405 is bonded via a bonding layer and/or
adhesive layer 1440 to an L0 substrate 1410. The L0 substrate 1410
includes a HD-DVD data format. The top of the L1 substrate 1405
includes two reflective layers 1415 and 1420 separated by an
intervening layer 1445. The L1 substrate 1405 further includes a
bonding layer 1412 and a cover layer 1414. The top of the L0
substrate 1410 includes two reflective layers 1425 and 1430
separated by an intervening layer 1435. The Blu-ray and HD-DVD
formats are read through their own substrates sides via optical
beams 1450 and 1455, respectively. A read inhibiting agent limits
the life of at least the Blu-ray and HD-DVD format and/or a portion
thereof. The read inhibiting agent resides in at least one of
intervening layer 1445, bonding layer 1440, intervening layer 1435,
the bonding layer 1412, and the cover layer 1414.
[0109] FIG. 16 above illustrates the hybrid construct of a Blu-ray
disc combined with an HD-DVD optical disc. This is a unique and
novel construction combining data layers that meet the
specifications of two different proposed formats within a single
optical disc. By using normal bonding and spincoating resins and/or
other cover layer constructs for each format, both data layers
would be permanent play data layers. The incorporation of reactive
materials and/or limited play mechanisms within the bonding layers,
and/or cover layer, and or/disc substrate, and/or reflective layers
adds limited play capability to part of or entire data layers. In
addition, the present invention also contemplates the combination
of limited play characteristics, permanent play characteristics,
and/or recordable layers within the construct of a single disc
containing Blu-ray and HD-DVD data layers.
Recordable Limited Life Optical Media
[0110] In applications of on-demand recording of digital data
including but not limited to audio or video such as music or
movies, it may be desirable to be able to record information onto
an optical disc that offers limited play capability for all or part
of the recorded information. This can also be combined with a
pre-recorded area or data layer within the disc structure.
[0111] In yet another embodiment consistent with the invention an
optical medium is disclosed that can be used at point of
distribution to selectively record data, including for example but
not limited to software, songs, albums, music videos, feature
films, or video segments that the customer desires to purchase. The
method of distribution and recording could be a customer service
station at a retail location with the associated recording device
and appropriate packaging system or a fully integrated kiosk that
is used directly by the consumer to automate the process and
transaction.
[0112] An optical disc product to meet these use requirements has
been designed combining a recordable data layer and a limited life
mechanism. This basic construct can be combined with any of the
preceding embodiment, including a pre-recorded second layer in a
limited play DVD-9 format. The use of a second recordable layer is
also possible
[0113] In one embodiment consistent with the invention the disc
construct follows the standard DVD-9 configuration of a bottom L0
disc half and/or substrate bonded to a top L1 disc half and/or
substrate. This grooved substrate is then coated with a DVD
recordable dye and metallized with a semi-reflective film to create
the recordable L0 data layer within a dual layer DVD-9 construct. A
read limiting dye is integrated within the adhesive used to bond
the L0 and L1 substrates. The L1 substrate is molded as a
pre-recorded data layer as is typical in a DVD-9 L1 data layer and
metallized with a full reflective layer. Optionally, a second
recordable layer may be used in a dual layer recordable construct.
In either product configuration, the read limiting dye in the
bonding layer limits access to the entire or selected areas of the
second data layer after a predetermined period of time, limiting
access to all or parts of the data stored on the optical disc.
Interactions between the reflective layers and the reactive bonding
layer can be prevented with a buffer layer applied to the
reflective layer prior to bonding.
[0114] The disc is authored so that when inserted into a player,
the L1 would be recognized as having been recorded and the L0
available for recording. The pre-recorded L1 data layer offers the
ability to place data on the L1 that can serve as a check region or
provide software for use in the player, kiosk, or recorder
application. The use of check regions within the data structure of
the disc can be employed to enhance the capability of a recordable
limited play product, defining the limited play areas and providing
access to selected parts of the recorded and pre-recorded
information. The L0 layer may also have pre-recorded data in the
recordable data area that contains information for the player,
recording drive, or kiosk station to use as a check disc region,
application information, or product configuration information.
[0115] The use of partially dispensing the reactive adhesive within
the bonding layer may also be utilized to block the ability of the
read laser to read limited areas of the recordable and/or
pre-recorded data layers. In this way, the media can be configured
to selectively allow limited play features to all of, or portions
of, the data pre-recorded and/or recorded within the disc.
[0116] While numerous embodiments, including the preferred
embodiments, of the invention have been illustrated and described,
it will be appreciated that various changes and/or combinations can
be made therein without departing from the spirit and scope of the
invention.
Controlled Application of Read Inhibiting Agent(s)
[0117] These embodiments provide an optical medium that contains
encoded information with two separate life times, a limited life
and an indefinite life. A DVD-9 with read inhibiting agent on only
a portion of the disc has been produced. Although this was done on
a DVD-9 format, the technique applies to all disc formats and
constructs. Authoring is accomplished so as to either restrict
access to data not physically blocked, or enabling access to that
data. These authoring techniques are an extension of those
disclosed in U.S. patent application Ser. Nos. 10/163,473,
10/163,855, 10/163,472, 10/837,826, 10/163,821, 10/651,627 and U.S.
Pat. No. 6,756,103, all hereafter incorporated by reference in
their entirety. A portion of the optical media without a read
inhibiting agent to block the laser and authoring is used to enable
access to a part of either layer which would play forever if
enabled while other data would have at least a major part of it
become physically unreadable on all players.
[0118] Discs were made with reactive dye bonding material dispensed
at the inner diameter (ID), middle, and outer diameter (OD) of the
disc with a dual dispense system. FIGS. 17 through 20 illustrate
distribution of the read inhibiting agent(s) consistent with the
present invention. FIG. 17 illustrates a read inhibiting agent
localized to a wedge section 1510 of the outer diameter. The
remaining area 1505 can be a bonding agent and/or a secondary read
inhibiting agent. FIG. 18 illustrates a read inhibiting agent
localized to a larger wedge section 1610 of the outer diameter. The
remaining area 1605 can be a bonding agent and/or a secondary read
inhibiting agent. FIG. 19 illustrates a read inhibiting agent
localized to a region surrounding the inner diameter 1710. The
remaining area 1705 can be a bonding agent and/or a secondary read
inhibiting agent. FIG. 20 illustrates a read inhibiting agent
localized to a region surrounding the inner diameter 1810. The
remaining area 1805 can be a bonding agent and/or a secondary read
inhibiting agent.
[0119] If two bonding resins are dispensed within the standard
dispense cycle, then a dramatic reduction in the use of costlier
reactive dye bonding resin or corrosive chemistry bonding resin can
be achieved with minor equipment and/or process modifications.
[0120] Benefits of dual dispense process include: active adhesive
use reduction (subsequent cost reduction); use reduction allows for
dye concentration increase (improved chemical stability); and
separation of active/inactive adhesives: would allow for a
secondary chemical failure mechanism to be implemented within the
inactive adhesive chemistry, for example combining reactive dye
chemistry with corrosion chemistry on different parts of the disc.
The secondary failure mechanism is disclosed in U.S. patent
application Ser. Nos. 10/163,473, 10/163,855, 10/163,472,
10/837,826, 10/163,821, 10/651,627 and U.S. Pat. No. 6,756,103, all
hereafter incorporated by reference in their entirety.
[0121] A DVD-9 with a reactive agent and/or material (such as a
reactive dye) on only a portion of the disc. This results in a
portion of the disc without a reactive agent and thus will not
prevent the laser from reading the encoded information in this
region. Authoring is used to enable access to a part of the L1
layer, the portion without the reactive material, which would play
forever while the data on a full side would have at least a major
part of it become unreadable on all players.
[0122] The dual dispense system can also be used to reduce the cost
of reactive dye or corrosion materials as mentioned above. For
performance equivalent to a Flexplay DVD-5 or Flexplay DVD-9, the
reactive bond resin can be applied at the ID of the disc while a
non-reactive bond resin is applied outside of that radius. The two
materials are then spun together leaving reactive material only at
the inner portion of the disc, which will still cause a boot
failure and eliminate access to the menu structure of the disc
navigation. The disc will no longer function after the
pre-determined stimulus activates the inner reactive dye or
reactive corrosive material area.
[0123] Optical degradation of a limited-play optical medium occurs
via exposure of a reactive dye or reactive corrosion agent to a
stimulus, such as for example, oxygen. For example, oxygen
transport to the reactive layer is limited by normal incidence bulk
diffusion through the polycarbonate "dummy" substrate and any other
intervening material layers. Oxygen transport can also occur
through disc-edge diffusion at the interface between the
reverse-mastered DVD-5 substrate and the dummy substrate or the
edges of the L0 and L1 substrates of a DVD-9. Disc-edge diffusion
is limited primarily to the inner and outer diameters of the DVD.
Modifications to the oxygen diffusion rates of any intervening
layers present between the external environment and the
oxygen-active layers will significantly affect the rate of optical
degradation of the limited-play media, thereby providing a
mechanism to control the useable life of the product.
Disc-Edge Diffusion Control
[0124] Disc-edge diffusion rates will differ from the normal
incidence bulk diffusion since the reactive layer is either exposed
at that narrow area or is protected by a secondary barrier (e.g.,
protective acrylate coating), not typically of the same composition
as other components of the typical limited-play optical media
system. If bulk diffusion rates are low enough, then disc-edge
diffusion will dominate, enabling useable disc life to be
controlled by the preferential optical degradation at either the
inner or outer diameter of the limited-play optical media.
Disc-edge diffusion can be controlled through composition and
thickness of the disc-edge barrier. Preferential disc failure
through disc-edge diffusion is then achieved by a required
playability verification at a predetermined point near either the
inner diameter or outer diameter of the limited-play optical media.
Dominant disc-edge diffusion rates can be achieved through the use
of thin-film diffusion barriers on the dummy substrate, reduced
oxygen diffusion rates through the dummy substrate (e.g., PMMA
substrate), or topical diffusion barriers on the surface of the
dummy substrate (e.g., protective barrier or semi-permeable
coating).
[0125] In order to shift away from edge diffusion being the primary
factor in the failure of the disc, a bonding technique has been
developed which keeps the reactive dye or corrosion chemistry away
from the outer edge of the disc yet still achieves appropriate
bonding properties and spacer layer thickness. This embodiment
involves dispensing two separate materials onto the disc during
bonding. Two dispense systems were implemented to work in parallel
to reduce cycle time. The reactive bond resin is applied at the ID
of the disc while a non-reactive or secondary failure mechanism
enabling bond resin is applied outside of that radius. The two
materials are then spun together leaving reactive material only at
the inner portion of the disc, which will still cause a boot
failure and eliminate access to the menu structure of the disc
navigation. The disc will no longer function after the
pre-determined stimulus activates the inner reactive dye or
reactive corrosive material area. The lifetime, or viewing window,
of the encoded information stored on the disc is determined by the
primary reactive agent in the center of the disc. In the case of a
secondary failure mechanism employed as referenced in U.S. patent
application Ser. Nos. 10/163,473, 10/163,855, 10/163,472,
10/837,826, 10/163,821, 10/651,627 and U.S. Pat. No. 6,756,103, all
hereafter incorporated by reference in their entirety, the second
material coated outside the ID could contain reactive corrosive
chemistry which would erode the reflective layer after the reactive
dye has rendered the disc unreadable. The dual dispense system can
also be used to reduce the cost of reactive dye or corrosion
materials by reducing the volume of material used per disc.
Bulk Diffusion Control
[0126] If disc-edge diffusion is not dominant in the limited-play
DVD system, then diffusion rates of the pre-determined stimulus
through the assembly will be limited primarily by the normal
incidence bulk diffusion rates of the components in the disc
assembly. Since diffusion rates through the fully reflective layer
(e.g., 60 nm aluminum) are negligible, bulk diffusion through the
bottom substrate or L0 substrate coated with a semi-reflective
layer and any diffusion barriers applied to that substrate will
determine total diffusion rates to the reactive layer. Possible
bulk diffusion control mechanisms are described in the following
preferred applications: [0127] 1) Diffusion limited substrate
composition [0128] 2) Thin barrier or semi-permeable coating
diffusion barrier [0129] 3) Thin-film diffusion barrier [0130] 4)
Inclusion of anti-oxidants in the substrate, reflective, or bonding
layers [0131] 5) Inclusion of reduction agents in the reactive dye
layer or reactive corrosive layer Oxygen Diffusion Limited L0
(DVD-9) or Bottom Dummy (DVD-Inverse 5) Substrate Composition
[0132] Current optical disc manufacturing utilizes optical grade
polycarbonate (PC). Oxygen permeability for polycarbonate is
approximately 100 .sup.cc-mm/.sub.m2.sub.-d. Decreasing the oxygen
permeability of the L0 or dummy substrate, in conjunction with
rapid kinetics of reactive dye bonding resin, allows the product
decay kinetics to be limited exclusively by the oxygen permeation
rate of the dummy substrate. Discs made with polymethylmethacrylate
(PMMA) for instance significantly increased the playtime as the
material has a much lower oxygen permeability compared to normal
optical grade polycarbonate. The material property is also very
stable regarding permeability so that the stability of the product
timing is very good and repeatable. The graphs below show readily
the extended playtime achievable with changes in the bulk diffusion
rate of oxygen as used in an oxygen reactive system with Flexplay
reactive dye chemistry:
[0133] FIG. 21 illustrates the extended play time using standard
PMMA, PC, and a barrier film of aluminum.
[0134] FIG. 22 illustrates the decay rates of samples made with
PMMA substrates with two different permeability rates for oxygen
showing the tuning capability of playtime.
Thin Coating Diffusion Barrier
[0135] Product decay kinetics control can be achieved by applying a
thin coating to the internal or external surface of the L0 or dummy
substrate. The coating has an index of refraction of approximately
1.55 and a very low optical absorbance at 650 nm. The coating is
applied through a spin-coating process with thickness variation no
greater than 10% (absolute). The coating thickness and permeability
would determine the product decay. A nominal coating thickness of
10.quadrature.m should provide the appropriate product decay
kinetics for commercially available optical hardcoatings.
Anti-oxidants and/or reduction agents can also be integrated within
these coatings. FIG. 23 illustrates coatings consistent with the
invention.
Thin-Film Diffusion Barrier
[0136] Bulk oxygen or other pre-determined stimulus diffusion rates
to the reactive layer can be reduced through the application of a
thin-film diffusion barrier. The thin-film diffusion barrier can be
applied to either the internal or external surface of the dummy or
L0 substrate. In essence, the film can be applied to any surface
between the environment and the reactive layer. Diffusion rates
through the thin-film diffusion barrier can be controlled through
film composition, thickness, and morphological structure. A wide
variety of materials (metals, metal oxides, etc.) can be used to
create the thin-film diffusion barrier, provided that precise
deposition techniques such as sputtering or physical vapor
deposition could be used to generate consistent barrier films in an
optical disc manufacturing environment.
[0137] The thin-film diffusion barrier exhibit minimal optical
reflection and absorbance for the wavelength used to read the data
recorded within the optical media. If applied to the external
surface of the substrate, it should also exhibit good mechanical
wear and fracture properties.
EXAMPLE 1
[0138] injection-molded 0.62 mm polycarbonate substrate with
reverse-mastered DVD5* data features; sputter coated with a fully
reflective metallic (aluminum) film: nominally 60 nm thick
[0139] oxygen-active adhesive material: TipSOC chemistry, rapid
kinetics--nominally 10 hour total deblocked life in limited-play
DVD without diffusion barrier: nominally 50.quadrature.m thick
[0140] injection-molded 0.56 mm polycarbonate featureless (mirror)
substrate; sputter coated with 2 nm aluminum-oxide film (internal
surface)
[0141] acrylate edge-coating to reduce disc-edge diffusion rates,
allowing bulk oxygen diffusion to dominate
[0142] The sputter coated thin film of aluminum-oxide provides a
significant barrier to oxygen diffusion. Oxygen permeation rates to
the oxygen-active adhesive are limited by grain-boundary diffusion
through the sputter coated aluminum-oxide thin film. For
room-temperature diffusion processes, grain boundary diffusion
rates are several orders of magnitude faster than bulk diffusion
rates. Utilization of ultra-thin metal-oxide films on a mirror
surface minimizes the undesired dummy substrate reflections and
metallic film optical absorbance, allowing data signal strength
from the reverse-mastered substrate to remain within an acceptable
operation level.
Preferential Optical Degradation
[0143] A limited-play DVD utilizing a thin-film diffusion barrier
as described above could be further tailored so that sharp
variations in aluminum-oxide sputtered film thickness would
generate preferential failure of the limited-play DVD in a "check"
region of the DVD program. This preferential failure would prevent
content degradation from occurring prior to the expiration of the
limited-play DVD by causing disc failure in a "check" region rather
than a uniform optical degradation that includes the content region
of the DVD.
[0144] Optical degradation rates will be significantly affected by
slight variations in the thickness of the sputtered thin film
diffusion barrier. Those sharp variations in aluminum-oxide film
thickness can be obtained by physically masking the selected
"check" region of the limited-play DVD. One effective means of
obtaining the preferential play failure would be accomplished
through using a 48.0 mm diameter center sputtering mask. This
masking arrangement would completely cover the lead-in area of the
DVD, resulting in a failure to successfully boot or navigate the
play menu prior to any content degradation of the viewed product.
Another effective method for preferential play failure would
utilize a check region in the "lead-out" of the limited-play DVD
and reduced diameter o.d. sputtering mask that places the mask
radially internal to the physical location of the "lead-out" check
region.
EXAMPLE A
[0145] injection-molded 0.62 mm polycarbonate substrate with
reverse-mastered DVD5* data features; sputter coated with a fully
reflective metallic (aluminum) film: nominally 60 nm thick
[0146] oxygen-active adhesive material: TipSOC chemistry, normal
kinetics--nominally 30 hour total deblocked life in limited-play
DVD without diffusion barrier: nominally 50.quadrature.m thick
[0147] injection-molded 0.56 mm polycarbonate featureless (mirror)
substrate; sputter coated with 2 nm aluminum-oxide film (internal
surface), i.d. sputtering mask 48.0 mm diameter
EXAMPLE B
[0148] injection-molded 0.62 mm polycarbonate substrate with
reverse-mastered DVD5* data features; sputter coated with a fully
reflective metallic (aluminum) film: nominally 60 nm thick
[0149] oxygen-active adhesive material: TipSOC chemistry, rapid
kinetics--nominally 10 hour total deblocked life in limited-play
DVD without diffusion barrier: nominally 50.quadrature.m thick
[0150] injection-molded 0.56 mm polycarbonate featureless (mirror)
substrate; sputter coated with 2 nm aluminum-oxide film (internal
surface)--i.d. sputtering mask at 30.0 mm diameter; secondary
sputter coating, nominal 2 nm aluminum-oxide film--i.d. sputtering
mask at 48.0 mm diameter
Authoring
[0151] A limited play optical device becomes unreadable over time
(e.g., 1-5 days), typically following some stimulus, such as
exposure to oxygen. In embodiments of the present invention, The
optical device is designed and authored, or the reading device is
programmed, so that the reading device to read from a desired
region before playing the rest of the content on the disc. If
information in that region, referred to here as a "check region,"
is unreadable, the player will not read from the rest of the
medium. This system is preferably used with discs that become
unplayable over time (e.g., in a few days) and is particularly
useful where the disc becomes unplayable not all at once but
progressively.
[0152] The check region is preferably provided in a place where the
disc would be expected to become unreadable earlier than most other
regions. In the case of a disc that becomes unreadable over time in
the presence of oxygen, the check region could be at an outer
peripheral region. By checking the playability of the check region
and preventing play if the check region is unplayable, the
situation of having a partially playable but deteriorated disc is
reduced or avoided. Authoring tools can be used to cause the check
region to be read first, and to cause the reader to generate an
error indicating that the disc is not readable. The reader could be
programmed or modified to accomplish this result.
[0153] DVD authoring describes the process of creating a DVD video
that can be played on a DVD player. DVD authoring software must
conform to the specifications set by the DVD Forum group in 1995,
and as they evolve from time to time to preserve maximum player
compatability. The specifications are complicated due to the number
of companies that were involved in creating them.
[0154] Examples of authoring vendors include Apple, Authoringware,
Avid, Blossom Technologies, Canopus, Daikin, DreamCom, DV Studio,
Futuretel, Houpert Digital Audio, InnovaCom, Intec America,
InterVideo, Margi Systems, Matrox, Mediachance, Microboards,
Minerva, Minnetonka Audio Software, MTC, NEC, Nero, Optibase,
Panasonic, Pegasys, Pinnacle, Philips, Pioneer, PixelTools, Q-Comm,
Roxio, SADie, Sonic Solutions, Sony Media Software, Sony
Professional, Spruce Technologies, Ulead, Visible Light, and
Vitech.
Corrosion
[0155] In the embodiments of the present invention, optical media
is disclosed wherein access to encoded information therein is
limited by affecting the reflectivity of the semi-reflective and/or
reflective layers. In optical disc media, the reading laser must be
reflected back to the read optics by these reflective layers so
that the encoded information stored thereon can be read. Depending
on the layer (i.e., single or dual layer discs), the reflective
material can be sensitive to the wavelength of the read laser. The
reflective layer can be any metal, combination of metals,
reflective dielectric film or films (e.g. SiN) or other reflective
material capable of undergoing the required/desired redox reaction
in the presence of oxygen or after the addition of oxygen to the
system. Metallic reflective layers are much less sensitive to laser
wavelength while dielectric films can be created which will be
transparent at one wavelength while reflecting another. Both types
of reflective layers can be used in optical media. Within the DVD,
HD-DVD, and Blu-ray specifications, reflective layers are typically
metallic and potentially subject to corrosion effects. The
chemistry and examples described in the following section are
independent of the read laser wavelength and will provide
limited-play capabilities via corrosive destruction in all optical
media formats that utilize metallic reflective layers including
DVD, HD-DVD, and Blu-Ray.
[0156] The reflective layer can be irreversibly altered by
oxidation or destruction of its reflective properties as a result
of pitting, corroding, dissolution, etc., or any combination of
these. (See U.S. Pat. Nos. 6,434,109, 6,343,063, 6,011,772,
6,641,886, 6,511,728, 6,537,635, 6,678,239, 6,756,103, and
5,815,484 and U.S. Patent Application Nos. 20030152019,
20030123379, 20030123302, 20030213710, 20030129408, 20030112737,
Ser. Nos. 10/649,504, 10/162,417, 10/163,473, 10/163,855,
10/163,472, 10/837,826, 10/163,821, 10/651,627 and 20010046204,
hereinafter incorporated by reference in their entirety.). It
should be pointed out that it is not essential in all applications
that the interfering layer covers an entire surface of the disc. It
may be only necessary to inhibit the reading of areas containing
critical information content. Various patents instruct that this
reactive layer can be applied to the disc at several locations (on
the surface of the disc, on the surface of the reflecting layer
itself, in the adhesive, etc. see patents above) using a variety of
techniques and can undergo the change from non-interfering to
interfering in response to various stimuli including oxygen see
U.S. Pat. Nos. 6,434,109, 6,343,063, 6,011,772, 6,641,886,
6,511,728, 6,537,635, 6,678,239, 6,756,103, and 5,815,484 and U.S.
Patent Application Nos. 20030152019, 20030123379, 20030123302,
20030213710, 20030129408, 20030112737, Ser. Nos. 10/649,504,
10/162,417, 10/163,473, 10/163,855, 10/163,472, 10/837,826,
10/163,821, 10/651,627 and 20010046204, hereinafter incorporated by
reference in their entirety.
[0157] It was desirable to determine the extent of corrosion of the
semi-reflective layer (L0) of optical media resulting from its
exposure to various corrosive agents under a variety of physical
and chemical conditions. Simulated DVD-9 discs were made using
bonding agents that contained the potentially corrosive materials
of the present invention, a polycarbonate blank with a typical
silver L0 layer, and a polycarbonate blank with no highly
reflective layer (L1). These discs were made in this way so that
visible-NIR light transmission of the thin L0 silver layer could be
monitored; an increase in optical transmission indicates the
dissolution or removal of the reflective metallic silver layer as a
result of the action of the corrosive agents of the present
invention. Using this spectrophotometric method it was possible to
evaluate the efficacy of corrosive agent variables such as
corrosive agent concentration, reflective silver layer (L0)
thickness, adhesive composition, atmospheric composition, and the
addition of kinetic regulators.
[0158] Bonding agent formulations which contained 1.0% of the test
corrosive agent were used to prepare the simulated DVD-9 discs
described above. The particular bonding agent of this test
contained greater than 50% by weight of polyethylene oxide moieties
in order to provide some polar character to the reaction matrix.
Initial readings of the transmission of the discs were made on a
Cary 50 Scan UV-Visible Spectrophotometer and the discs were then
stored in the dark at ambient temperature and humidity. Readings
were made periodically over a 7 day period. FIG. 24 represents
typical transmission spectra of the L0 layer of the simulated DVD-9
disc that contained MBI in the bonding agent over this 7 day time
period; the increasing % T over time is indicative of a loss of
silver metal layer as a result of corrosion.
[0159] From the sulfur containing agents shown below, MBI was
selected as the most reactive corrosive agent with current bonding
agent formulations. Results of these tests are shown in TABLE 1.
The less reactive materials in this test may prove more effective
with changes in the bonding agent chemistry. TABLE-US-00001 TABLE I
Comparison of the increase in light transmission at 1000 nm that
occurred after 48 hours of ambient air storage of the simulated
DVD-9 discs that contained the various sulfur containing agents in
the bonding agent layer. ##STR1## ##STR2## ##STR3## ##STR4##
##STR5## ##STR6## ##STR7## % Increase in Transmission @ 1000 nm
after 48 Corrosive Agent hours in air MBI 2-Mercaptobenzimidazole
(CAS 583-39-1) 8 MMBI 2-Mercapto-5-methylbenzimidazole 5.6 (CAS
27231-36-3) DPTU N,N-Diphenylthiourea (CAS 102-08-9) 4.8 MNBI
2-Nitro-5-methylbenzimidazole 3.4 (CAS 6325-91-3) MBT
2-Mercaptobenzothiazole (CAS 149-30-4) 0.8 DBTU N,N-Dibutylthiourea
(CAS 109-46-6) 0.7 MBO 2-Mercaptobenzoxazole (CAS 2382-96-9) 0
[0160] Another quick screening method for the ability of various
agents to corrode the L0 silver layer was used. Drops of SR495
containing 1% to 2% of the test agents were placed on the metal
surface of a standard semi-reflective L0 silver coated substrate
and observed over a 24-72 hour period while exposed to air. Changes
in the appearance of the silver layer as well as its adhesion to
the polycarbonate substrate were noted over time and compared to
appropriate controls. The following table describes the corrosion
effects that were observed. TABLE-US-00002 Test Additive Effect on
Silver Reflectivity Control (no additive) no effect, fully
reflective silver remains after 72 hrs. MBI blackish at 1-2 hrs,
silver dissolved in .about.4 hrs Dithiothreitol dissolved silver in
<24 hrs Mercaptothiazoline blackish discoloration
3-Mercapto-1,2-propanediol blackish discoloration Cysteine methyl
ester HCl black/bronze discoloration with clearing in 72 hrs
Dimethylaminoethanethiol HCl blackish discoloration with some
clearing of silver
[0161] These compounds are also known as "bleaching accelerators"
in the photographic industry (U.S. Pat. Nos. 3,893,858; 4,865,956,
herein incorporated by reference in their entirety) where they are
used in conjunction with oxidizing agents to accelerate the
oxidation of silver during the development of color photographic
images. Therefore, the above type compounds were also tested in
combination with the following benzoquinone oxidants and their
reduced precursors to evaluate their ability to corrode the L0
silver layer. The "limited play" format may thus be further
controlled in its timing characteristics by utilization of the
inactive hydroquinone precurser in the manufacture of the DVD disc;
subsequent exposure to air will generate the active benzoquinone
oxidant at the proper time. Combinations of the following compounds
with the above thiols appeared to improve/accelerate their ability
to oxidize the silver layer in the test described above:
2,5-Di-t-amylhydroquinone (Lowinox AH25); 2,5-t-butylhydroquinone;
2,5-t-Butylbenzoquinone; 2,5-Dichlorohydroquinone;
2,5-Dichlorobenzoquinone; 2,3-Dicyanohydroquinone; and
2,3-Dicyanobenzoquinone. Also tested were imidazole, benzimidazole,
benzotriazole, mercaptobenzimidazole, and
1-phenyltetrazole-5-thiol, as these were also described as bleach
accelerators. Combinations of imidazole and the hydroquinones
appeared particularly effective in dissolving the silver layer.
[0162] In the embodiments of the present invention, a corrosive
agent is used to inhibit the reading of the encoded optical data
layer via oxygen initiated corrosion of the reflective layer. The
corrosion results in the destruction of the reflective layer to
such an extent that the film no longer has sufficient reflectivity
to support the optical reading of the reflective film by a
conventional player. The corrosion reaction of the present
embodiment involves the utilization of sulfur compounds, and, in
particular thioureas, the leading example of which is
2-mercaptobenzimidazole (2-MBI, Sigma-Aldrich Catalog #M320-5,
Milwaukee, Wis. 53201) which has the ability, in the presence of
oxygen, to corrode reflective thin silver layers as are typically
found within optical media. It has been demonstrated that stable
high quality optical media can be manufactured containing 2-MBI in
the bonding agent with standard replicating equipment when the
completed discs are stored in a suitable oxygen free atmosphere and
that said discs become unplayable within a predetermined time
period after being exposed to ambient air.
EXAMPLE 1
[0163] DVD-9 discs were made with silver L0 and L1 layers, both on
"low gas permeation" polycarbonate utilizing bonding agents that
had the following compositions; Formulation A was a control that
contained no 2-MBI, Formulation B contained 0.25% 2-MBI, and
Formulation C contained 0.5% 2-MBI. Common to all three
formulations were the following materials: SR415 and SR495
(monomers, Sartomer Company, Inc.; Exton, Pa. 19341), and Irgacure
819 (photoinitiator, Ciba Specialty Chemicals, Tarrytown, N.Y.
10591). TABLE-US-00003 Weight, grams Component A B C SR415 201.0
201.0 201.0 SR495 201.0 201.0 201.0 IC819 7.70 7.70 7.70 2-MBI
1.025 2.05
[0164] Immediately after manufacture, the DVD-9 discs were sealed
in plastic packages containing oxygen scavenger material as
described in previous patent applications (see U.S. patent
application Ser. No. 10/162,417, hereafter incorporated by
reference in its entirety). To demonstrate the oxygen dependence of
the limited play mechanism of the present invention, playability
comparisons were made between discs that had been opened and stored
in air and those that remained in the oxygen free packages and
played as soon as they were opened; storage temperatures were room
temperature and 60.degree. C. The discs were periodically tested
for playability on a typical DVD player (Samsung DVD P-231). The
discs were considered to have failed when the player would not
recognize that disc (boot failure). Results are shown in the
following table. TABLE-US-00004 Days Storage until Boot Failure
60.degree. C. RT (20.degree. C.) Formulation air cryovac air
cryovac A: 0% MBI >60 >30 >90 >90 B: 0.25% MBI <3
>14 20 >77 C: 0.50% MBI <3 >14 17 >77
[0165] It will be noted that the above table provides evidence of
the oxygen dependence of the limited play corrosion based system
and the dependence of the corrosion rate on the concentration of
MBI.
EXAMPLE 2
[0166] Further work has shown that playtime failure is strongly
dependent on the thickness of the L0 silver layer. DVD-9 discs were
made with standard DVD grade polycarbonate using a bonding agent
that was made up by blending 486 grams of SR415 (Sartomer Company,
Inc.), 486 grams of SR495 (Sartomer), 18.6 grams of Irgacure 819
(Ciba Specialty Chemicals), and 10.0 grams of
2-mercaptobenzimidazole (2-MBI, Sigma-Aldrich). The thickness of
the L0 silver layer of this set of discs was varied and
characterized by reflectivity values from 16% R14H to 24% R14H. As
described in Example 1, the discs were manufactured, stored in
oxygen-free bags which were opened at the start of playtime
testing, and tested on a typical DVD player. Playtime failure was
determined as the number of elapsed hours from the time the discs
were removed from the oxygen free bags to the time that the discs
could not be recognized by the DVD player. These results are shown
in the following table as two values: Last Hour Played (the last
hour that the disc was successfully played)/First Hour of Boot
Failure (the first hour that the disc could not be played).
TABLE-US-00005 Storage Hours in Air to Boot Failure Last Hour
Played/First Hour of Boot Failure 16% R14H 18% R14H 21% R14H 24%
R14H 20/35 28/47 52/69 96/336
[0167] The table shows increasingly longer playtimes in the discs
with the more reflective, and thus thicker, L0 silver layers.
[0168] The increased ease of silver oxidation in the present
invention may be attributed to several features of the combination
of the thin silver L0 coating and the chemical properties of
mercaptans like MBI. The binding of MBI to the silver surface
lowers the redox potential of the silver making it easier to
undergo air oxidation (Tarasankai Pal, Current Science, 83, 627-628
(2002)). It also complexes with the generated oxidized form of
silver, helping to maintain the low oxidation potential in the face
of increasing silver ion concentrations (G. I. P. Levenson, "The
Theory of the Photographic Process 4.sup.th Edition" chapter 15, T.
H. James (ed.), Macmillan publishing Co. Inc., New York, 1977; U.
S. Pat. No. 5,641,616 and references therein). In addition,
heterogeneity in the thin silver L0 layer can lead to areas
favoring increased air oxidation (Pal (2002), Wei Ping Cai et. al.,
J. Appl. Phys., 83, 1705-1710 (1998)). The fact that MBI is
reportedly used as an antioxidant in the manufacture of industrial
rubber (Zenovia Moldovan, Acta Chim. Slov., 49, 909-916 (2002);
U.S. Pat. No. 5,666,994, herein incorporated by reference in its
entirety) and as an agent to inhibit corrosion of brass and copper
(Assouli et. al., Corrosion, 60, 604-612 (2004); Robert B.
Faltermeier, Studies in Conservation, 44, 121-128 (1999)) supports
our contention that the observed corrosion effects in our system
are not expected. In addition, MBI has been used as a corrosion
inhibiting agent in radiation curable compositions for optical
media (U.S. Patent Application US 2003/0008950 A1, herein
incorporated by reference in its entirety).
[0169] The chemical nature of the monomers and additives that are
utilized to formulate the bonding agents of the present invention
has an important effect on the rate of corrosion of the silver
layers. Since it is well known that rates of redox reactions in
polymer media are strongly dependent on the amount of humidity
(water) present, the incorporation of water attracting materials
and monomers has been found to be of advantage. In particular, the
utilization of highly ethoxylated monomers has been found to be
particularly advantageous. Examples of these monomers include
CD9038, bisphenolA diacrylate with 30 units of ethylene oxide;
SR415, trimethyolpropane triacrylate with 20 units of ethylene
oxide; SR610, polyethylene glycol 600 diacrylate; and SR344,
polyethylene glycol 400 diacrylate (all available from Sartomer
Co.). The cured bonding agents containing MBI typically show
increased corrosion rates, and thereby shorter limited life
playtimes, as the concentration of ethylene oxide moieties is
increased from about 5% by weight up to as high as 80% by weight.
The preferred level of ethylene oxide is above 50% by weight.
Additives and monomers that contain other hydrophilizing groups
such as hydroxyl, carboxyl, amides, and amines, and various salts
may also utilized both alone and in combination with others. This
listing of hydrophilic moieties is not all inclusive and those
skilled in the art may combine a wide variety of hydrophilic
functionalities, both polymerizable and non-polymerizable, in order
to balance the corrosion rates with the physical robustness of the
limited play disc.
[0170] Another means of controlling the rate and timing of the
corrosion reactions is via the addition of reducing agents. These
reducing agents will, after the optical media is exposed to the
atmosphere, preferentially react with the initial influx of oxygen
until the reducing agent is consumed, at which point the corrosive
agent will become active in causing destruction of the reflective
properties of the metal layer(s). As an alternative explanation,
the reducing agent may cause the active corrosive materials to
exist in a lower oxidation state which is inert to the reflective
metal; after the reducing agent is consumed, the corrosive agent
precursor is converted (oxidized) by air to form the corrosive
material. The following example utilizes tetrachlorohydroquinone
(TCHQ) as a non-corrosive precursor in the bonding agent; after
exposure to oxygen, TCHQ is oxidized to the benzoquinone form which
has a higher oxidation potential and thus is more able to oxidize
the reflective silver layers. As an alternative proposed corrosion
mechanism, it is also possible that the benzoquinone form releases
chloride ion which is known to cause corrosion of metal layers in
optical media.
EXAMPLE 3
[0171] The use of reducing agents has been successfully used to
control the oxidation of silver layers by tetrachlorohydroquinone
(TCHQ) in the bonding agent of the optical media. DVD-9 discs were
made with Formulations D and E which contained TCHQ alone and TCHQ
in combination with ascorbic acid. TABLE-US-00006 Weight, grams
Formulation# Component D E SR415 97.88 97.63 SR495 97.88 97.63
IC819 3.74 3.74 TCHQ 0.50 0.50 Ascorbic Acid 0.50
[0172] The discs were equilibrated in the absence of air as
previously described for one week and then opened and stored in air
in a wet chamber to accelerate the corrosion reactions. The discs
were tested for playability as described in Example 1; the
increased playtime of formulation E is a result of the presence of
ascorbic acid: TABLE-US-00007 Last Day of First Day of Formulation
Play Boot Failure D 2 3 E 6 10
[0173] Similar effects of increased playtime have been observed
using ascorbyl palmitate and stannous octanoate as reducing agents.
Many other reducing agents as described in U.S. patent application
Ser. Nos. 10/163,473, 10/163,855, 10/163,472, 10/837,826,
10/163,821, 10/651,627 and U.S. Pat. No. 6,756,103, all hereafter
incorporated by reference in their entirety, may be applicable here
in varying formulations as may be formulated by those skilled in
the art.
[0174] Stannous octanoate has been found to be the preferred
reducing agent for the control of the corrosion based limited-play
timing mechanisms of the present invention, but has the unfortunate
ability to occasionally cause premature polymerization of typical
monomer mixtures. To prevent this, the addition of increased levels
of polymerization inhibitors, such as hydroquinones, has allowed
the formulation of corrosive bonding agents that exhibit stable
viscosities for up to several days in the presence of the stannous
salt. The preferred hydroquinone is 2,5-di-tert-pentylhydroquinone
(Lowinox AH250, Great Lakes Chemical Corporation, West Lafayette,
Ind.) used at a 0.10% to 1.0% by weight concentration and
preferably between 0.2% to 0.5% by weight concentration. Another
compound that has shown success in controlling viscosity of monomer
formulations in the presence of stannous salts is phenothiazine
(CAS 92-84-2; Sigma-Aldrich Cat. No. P14831) when used at similar
levels as Lowinox AH25 above.
[0175] An additional problem that arises in the use of stannous
octanoate with the hydrophilic monomer mixtures that are preferred
in the time-controlled corrosive bonding agent systems described
above is the formation of hazy mixtures. Presumably, this is a
result of poor solubility of the stannous salt in the predominantly
polyethylene oxide containing mixture. We have found that clear
solutions are formed when stannous octanoate is first dissolved in
tripropylene glycol (TPG, CAS 24800-44-0; Sigma-Aldrich Cat.
No.187593). Since TPG is not expected to copolymerize within the
cured bonding agents and may exhibit undesirable syneresis, tests
were done on peeled discs at 60C in order to accentuate the
observation of any possible exudation of liquid; no syneresis or
exudation was observed under these conditions when TPG was
incorporated at levels up to 10% by weight of the cured bonding
agent.
EXAMPLE 4
[0176] Demonstrates that the incorporation of TPG also has a
beneficial effect on maintaining a high corrosion rate of silver
metal layers in DVD-9 discs even when stored in air under low
humidity conditions. Stannous octanoate was pre-dissolved in
varying amounts of TPG and combined with Stock Solution F to make
Bonding Agents G, H, and I. The resulting bonding agents contained
2.7%-3% MBI, 0.25% stannous octanoate and 0%, 5%, and 10% by weight
TPG. TABLE-US-00008 Stock Solution F Weight, % by Component grams
Weight CD9038 540 54.00% SR238 175 17.50% SR495 142.5 14.25% SR440
100 10.00% Lowinox AH25 2.5 0.25% IC819 10 1.00% MBI 30 3.00%
Formulation # Weight, grams Component G H I Stock Solution F 249.38
236.88 224.38 TPG 0 12.5 25 Stannous Octanoate 0.625 0.625
0.625
[0177] DVD-9 discs were made as described above in Examples 1 and
2; L0 thickness was quantified by a 24% R14H reflectivity and
standard grade polycarbonate was used. The discs were stored in
oxygen free bags for 4 days, then opened and stored in air at room
temperature under the three different humidity conditions, dry (one
gallon polyethylene container with desiccant packages), ambient
(open to room air), and wet (one gallon polyethylene container with
wet paper towels on the bottom). The results shown below as Average
Playtime were determined as the midpoint between the last day that
the disc was observed to play and the first day that the disc would
not boot on the Samsung DVD Player. TABLE-US-00009 Average
Playtime, Days G H I 0% TPG 5% TPG 10% TPG Air Storage Dry (<10%
RH) 17.5 12.5 9 Condition ambient 5 3.5 3.5 100% RH 2.5 2.5 2.5
[0178] These results show that increasing the TPG level has the
benefit of reducing the variation in limited playtime between high
and low humidity conditions.
Dye Compounds as Reactive Material and/or Read Inhibiting
Agents
[0179] The reading laser wavelength for HD-DVD and Blu-ray discs
has changed from standard CD (780 nm) and standard DVD (650 nm)
optical media to 405 nm. In order to block the blue laser
wavelength, the present invention discloses a group of reactive
materials that exhibit absorptive properties at the 405 nm
frequency. In addition to dyes that can simply absorb the read
laser wavelength, dyes that can be both reduced to the colorless
leuco-form as well as be re-oxidized by oxygen to the colored form
or change absorption characteristics when exposed to a triggering
stimulus can also be used. It is also desirable, but not necessary,
that the reduced free dye (e.g., leuco dye) responds to a mechanism
for controlling the rate of oxidation (e.g., the re-oxidation of
leuco methylene blue (i.e., leuco dye) can be controlled by a
reducing agent such as stannous octanoate. (US 2004/0137188 A1
herein incorporated by reference in its entirety).
[0180] One embodiment consistent with the present invention
comprises the use of a chemically blocked and/or modified and/or
protected reactive dye(s) in the reactive layer. These compounds
will de-block within a predetermined time period after the disc is
manufactured or packaged, and typically before the disc is used by
the consumer. This is desirable when the stimulus that triggers the
reaction that causes the disc to become unplayable (e.g.,
atmospheric oxygen) can trigger this reaction during the
manufacturing of the disc, and thus measures need to be taken so
that the reactive compound is not activated during the
manufacturing of the disc. For example, in the case of oxygen
triggered reactions, unless a blocked form of the reactive compound
is used, manufacturing may need to take place in an oxygen free
environment, such as a nitrogen atmosphere.
[0181] Specific exemplary blocked dyes and methods of preparing
leuco-dye precursors are disclosed. Adhesive compositions which
permit the de-blocking and oxidation of the leuco dye precursors at
acceptable rates and methods of applying dyes and dye precursors to
optical discs both on the surface of optical discs and as bonding
layers for optical discs are disclosed (see previous patents for
methods).
[0182] Also disclosed is the use of basic materials to increase the
rate of de-blocking of the protected leuco dye precursors in
blocked leuco dye-containing layers in or on optical discs.
[0183] Classes of dyes available for use in Blu-ray include for
example, but are not limited to, azomethine dyes, acridines, styryl
type dyes, cyanine dyes, oxonols, merocyanines, anthraquinones,
naphthoquinones, quinoneimines, diaryl and triarylmethane type
dyes, phenazine dyes, thiazine dyes, oxazine dyes, coumarin type
dyes, and polyhydroxybenzenes or aminophenol derivatives. Preferred
classes of these dyes are shown below. These structures are not
intended to be all inclusive but to serve as examples of useful dye
classes. Members belonging to these dye-classes are reduced easily,
can be air oxidized, and either absorb in the desired spectral
window of 400-450 nm for blocking the reading laser or slightly
further to the red. The fact that their maximum absorption peak is
not exactly in the effective window is not a problem as long as
their absorption curves are broad and increased concentrations lead
to the desired coverage in the window. ##STR8##
[0184] As an example, the following synthetic scheme starting with
the well known phenothiazinone dye, methylene violet, leads to a
reduced and blocked compound that after de-blocking leads to air
oxidation and regeneration of the starting dye. This process is
similar to that described in U.S. patent application Ser. Nos.
10/163,473, 10/163,855, 10/163,472, 10/837,826, 10/163,821,
10/651,627 and U.S. Pat. No. 6,756,103, all hereafter incorporated
by reference in their entirety, which describes the process for
using methylene blue in 650 nm DVD applications. The methylene
violet dye has a broad absorption peak at 580 nm with a strong
secondary peak at 470 nm. At reasonable concentrations, it can
provide good absorption in the 400-450 nm window. ##STR9##
[0185] The compound has the added benefit that two blocked
colorless forms of the dye can be made which are stable to air
oxidation, but following de-blocking yield the leuco-form of the
dye which rapidly air oxidizes to the colored form.
[0186] As stated above, other potential chromophores for use are
the quinoneimines, including indamines, indophenols, and
indoanilines, such as those disclosed in U.S. Pat. No. 5,424,475,
herein incorporated by reference in its entirety.
SPECIFIC EXAMPLES
[0187] ##STR10##
[0188] The quinoneimines along with the naphthoquinone and
anthraquinone dyes are further described in the literature at M.
Matsuoka, et al., J. Soc. Dyers Colour, vol 103, p 167 (1987) and
"Chemistry and Applications of Leuco Dyes", chapter 2, edited by
Ramaiah Muthyala, Plenum Press, NY (1997)
SPECIFIC EXAMPLES
[0189] ##STR11## Diarylmethane and triarylmethane dye types, such
as those disclosed in U.S. Pat. No. 5,330,864 and herein
incorporated by reference in its entirety, are also potentially
useful for this application and include for example: ##STR12##
Although it usually requires a strong oxidant to oxidize the
reduced form of this type of dye, there are some that can be air
oxidized in the presence of catalyst and light. ##STR13##
[0190] Further information can be found in the literature such
as:Chemistry and Applications of Leuco Dyes", chapter 5, edited by
Ramaiah Muthyala, Plenum Press, NY (1997)
[0191] Oxazine, thiazine, and phenazine dye types are also
appropriate for the application in blue laser optical disc formats.
Leuco forms of all these type dyes are known. Phenazines may be
especially useful since they generally absorb close to the desired
region. Derivatives of thiazine and oxazine dyes are known that are
close enough to the desired region so that high concentrations give
coverage. General Structure of These Dyes: ##STR14## Where R1, R2,
R3 is NZ.sub.2, NHZ, hydrogen, alkyl, aryl, alkoxy, halogens,
hydroxyl, CN, substituted thiols, SO2 alkyl, SO2 aryl, CO2 alkyl,
or CO2 aryl, where alkyl and aryl can be substituted and may
include atoms necessary to complete an aromatic or acyclic ring
system, which may contain heteroatoms and substitution, where Z can
be selected from the group of hydrogen, alkyl, aryl, alkoxy,
substituted alkyl, alkoxy, and aryl, substituted alkyl, alkoxy, and
aryl, SO2 alkyl, SO2 aryl, CO2 alkyl, or CO2 aryl, where alkyl and
aryl can be substituted and may include atoms necessary to complete
an aromatic or acyclic ring system, which may contain heteroatoms
and substitution. [0192] Where X is selected from NZ, O, S, N, or
Se. [0193] Where Y is selected from O or NR.
SPECIFIC EXAMPLE
[0194] ##STR15##
[0195] Further descriptions of these dyes are included but not
limited to "Chemistry and Applications of Leuco Dyes", chapter 3,
edited by Ramaiah Muthyala, Plenum Press, NY (1997). References for
thiazine, oxazine and phenazines can be found at J. Daneke et al.,
Ann Chem., vol 740, p 52 (1970); B. I. Stepanov, Izv. Vyssh. Zaved.
Khim. Khim. Tekhnol., vol 24, p 341 (1989); U.S. Pat. Nos.
4,622,395; 4,670,374, herein incorporated by reference in their
entirety; European patent 177,328; U.S. Pat. Nos. 4,478,687; 4,647,
525; 4,889,931; 4,889,932, all herein incorporated by reference in
their entirety and European patent 339,869
[0196] While members of the above classes of dyes can be useful for
providing a reactive material to prevent a blue laser from reading
encoded data in both HD-DVD and Blu-ray optical media formats, it
was found that the use of 2-arylamino-1,4-naphthoquinones were
especially useful do to the ease and cost of their synthesis.
2-arylamino-1,4-naphthoquinones with the donor groups confined to
the quinoid ring form a class of compounds with a relatively low
intensity visible band (.epsilon..about.4000) in the range of
430-500 nm for a single amino-donor or near 550 nm if two amino
groups are present. Substituents in the aryl ring have the effect
for a typical donor-acceptor chromogen, and the absorption maxima
fall in the range of 435-560 nm for electron withdrawing vs
donating substituents respectively. The isomeric
4-arylamino-1,2-naphthoquinones may also be used and affords the
advantage of greater absorption intensities (.epsilon.=10,000). In
the case where oxygen (air) is the stimulus for causing the optical
media to become unplayable, the reactive colorless leuco-form of
these compounds are useful but must be protected from premature air
oxidation during the manufacturing process. This can be
accomplished by a variety of blocking groups including but not
limited to esters, silyl ethers, carbonates, phosphinates,
sulfonates, and ethers (see US 2004/0137188 A1 for other leaving
groups). The type of blocking group can be chosen to give a
specific rate of hydrolysis (de-blocking) in order to give control
of the manufacturing process. Examples of synthesized dyes are
given in FIGS. 1-3. The de-blocking of the protective group is
accomplished with the aid of a variety of basic primary, secondary
and tertiary amines including but not limited to imidazole,
diisopropylamine, dodecylamine, tripentylamine, tinuvin 292,
aminohexanol, aminoethylmorpholine, dihexylamine, diisobutylamine,
aminoethylpiperazine, aminoethoxyethanol and dioctylamine. As would
be expected, the hydrophilic/hydrophobic character of the adhesive
can have a pronounced effect on both the rates of de-blocking and
air oxidation of the leuco-form of the dye. Generally, the rates
are faster in hydrophilic environments.
[0197] In order to evaluate the various novel blocked dyes as well
as other parameters involved in their ultimate use, discs were
initially prepared that did not contain the reflective layer in
order to follow the kinetics of de-blocking and air oxidation using
a UV/visible spectrometer (Varian Cary 50 Scan). The general
synthetic scheme, (examples 1, 2) used to prepare the various
derivatives of 2-(N-methylaminobenzene)-1-4-napthoquinone is given
below. This same scheme was used to prepare the unmethylated
derivatives by using aniline as the starting material. FIG. 4
represents data from a disc made as directed and then observed in
air over a 70 hr period. Initially, there is no absorption in the
visible region of the spectrum but after the 70 hr period complete
oxidation of the de-blocked, leuco-dye has occurred as evidenced by
the peak at 463 nm (the absorption peak of
2-(N-methylaminobenzene)-1-4-napthoquinone). Similar discs which
were vacuum sealed in cryovac bags with oxygen scavengers remained
colorless during this same time period both at room temperature and
at 60.degree. C. indicating that the transformation from a
colorless to a colored state is oxygen driven. FIG. 5 indicates
that the rate of de-blocking of the protected dyes is dependent on
the base used. Thus by regulating the amine used it is possible to
design the time frame for the de-blocking reaction. Likewise, if
one keeps the base a constant in the adhesive mix and varies the
protected dyes used, one observes various rates of oxidation
(de-blocking) depending on the dye and protective group (see FIG.
60). Therefore by regulating both the base used and the blocking
group used to protect the dye it is possible to provide limited
play discs with designed time limits of play.
Example 1
Preparation of 2-(N-methylaminobenzene)-1,4-naphthoquinone
[0198] ##STR16##
[0199] To a 250 ml round-bottomed flask is added 5.00 g (0.032
moles) of 1,4-naphthoquinone (Aldrich Chemicals, Milwaukee, Wis.),
and 90 ml of 200 proof, anhydrous ethanol. This mixture is heated
to reflux until complete solution occurs at which point the
temperature is lowered to 50.degree. C. This solution is stirred
using a magnetic stirrer and 4.06 g (0.038 moles) of
N-Methylaniline (Aldrich Chemicals, Milwaukee, Wis.) is added. This
is stirred for 3 hrs at 50.degree. C. and then the temperature is
lowered to 40.degree. C. for several hours and allowed to cool to
room temperature overnight. A precipitate forms. The mixture is
reheated to 40.degree. C. for 2 more hours and allowed to cool to
room temperature before filtering off 1.0 g of tan solid using a
Buchner funnel and #4 filter paper. The filtrate is allowed to stir
another 12 hrs at room temperature and then filtered to yield 2.45
g of orange crystals. The filtrate is concentrated down using a
rotary evaporator to .about.30 ml and let stand overnight. An
additional 1.65 g of product is isolated for a total of 4.15g (50%
total yield). The dye can be recrystallized from methanol or
ethanol and has an absorption max. in MeOH of 463 nm.
Example 2
Preparation of Chloroacetylated Dye 4-60
[0200] ##STR17##
[0201] To a 100 ml addition funnel is added 50 ml of methylene
chloride, 0.50 g (0.002 moles) of
2-(N-methylaminobenzene)1,4-naphthoquinone, 50 ml of water, 0.30 g
(0.001 moles) of tetrabutylammonium bromide (TBABr) and 0.75 g
(0.004 moles) of sodium hydrosulfite (Aldrich Chemicals, Milwaukee,
Wis.). This mixture is gently shaken until the methylene chloride
layer changes color from orange to light yellow (the reduced
naphthoquinone). The addition funnel is then placed on top of a
medium fritted funnel containing 5 g of sodium sulfate drying agent
that is attached to a 100 ml three-necked round-bottom flask
containing 30 ml of methylene chloride kept at 5.degree. C. using
an ice bath. The entire system is purged with argon while the
methylene chloride layer containing leuco-dye is passed from the
addition funnel through the sodium sulfate pad into the cold flask.
To this cooled solution is added 0.6 ml (0.004 moles) of
triethylamine followed by 0.32 ml (0.004 moles) of chloroacetic
acid (Aldrich Chemicals, Milwaukee, Wis.). This solution is stirred
at 10.degree. C. for 2hrs and then allowed to warm to room
temperature over the next 4 hours. The solution is then evaporated
down to near dryness using a rotary evaporator. To this dark
residue is added 50 ml of ether causing the formation of a white
precipitate (triethyamine-hydrochloride). This is left overnight
then filtered. The ether solution is evaporated to dryness on a
rotary evaporator and then the residue is dissolved in 20 ml of a
6:4 mixture of methylene chloride/hexanes. This is then added to a
20.times.250 mm medium pressure chromatography column packed with
5-20 .mu. silica gel which had been pre-wet with the same mixture
of solvents. The material is then eluted with 7:3 methylene
chloride/hexanes. The fractions containing pure compound are
combined and evaporated to yield an oil which crystallizes on
standing. The reaction and chromatography are monitored by TLC
using silica gel coated plates and eluting with 7:3 methylene
chloride/hexanes. This gives a product spot with an Rf=0.7 that
turns orange when treated with 1 N sodium hydroxide. 6.1 g of
product isolated as above was dissolved in 50 ml of n-butanol at
reflux and let cool slowly at room temperature to yield 4.9 g of
white crystals (M.P. 101-102.degree. C.)
Example 3
Preparation of Discs Using Dye 4-60
[0202] The adhesive used in the manufacture of the discs was
composed of: TABLE-US-00010 Components Wgt % Supplier CD9038 62.87
Sartomer, West Chester, PA SR494 8.30 Sartomer, West Chester, PA
SR440 8.30 Sartomer, West Chester, PA Lowinox AH25 0.21 Great Lakes
Chemical, W. Lafayette, IN Irgacure 819 0.83 Ciba Geigy, Tarrytown,
NY 2-Mercaptobenzimidazole 2.49 Aldrich Chemicals, Milwaukee,
WI
[0203] 4.5 g of Dye 4-60 is added to 124.5 g of the above
formulation in a dark glass bottle and briefly heated to 60.degree.
C. This is then placed in a sonicator (Branson model 2200) in which
the water level is above the level of the adhesive mix in the
bottle and sonicated for 15 min. Complete solution of dye results.
To this solution is added a mixture of 6.0 g of
Sn(II)ethylhexanoate (Aldrich Chemicals, Milwaukee, Wis.) in 12.0 g
of Tri(propylene)glycol (Aldrich Chemicals, Milwaukee, Wis.). This
is sonicated for several minutes after hand shaking to blend.
Finally, to this clear solution is added 3.0 g (2%) of powdered
imidazole (Aldrich Chemicals, Milwaukee, Wis.) and the mix is
sonicated for an additional 15 min.
[0204] A DVD clear half disc (an umetallized 0.6 mm thick and 120
mm diameter polycarbonate disc) is centered on a laboratory spin
coating turntable. 0.60 ml of the above dye/adhesive mix is applied
uniformly in a circular ring by a syringe at about 20 mm from the
center of the disc. The disc to be bonded is then placed over the
adhesive and the combination spun at roughly 60-200 rpm's until the
adhesive covers the entire disc uniformly. At this point, the disc
containing the adhesive is photo-cured with a Xenon Cool Cure
XL-DVD flash lamp using a 2 sec exposure (10 pulses) set at its
maximum setting. The process will yield a clear, fully cured
acrylate bonded disc. Some discs were vacuum packed in cryovac bags
containing oxygen scavengers in order to evaluate their stability
in an inert system (no oxygen). TABLE-US-00011 Compound 1 ##STR18##
R R.sub.1 COC.sub.6H.sub.5 H, CH.sub.3 COCCl.sub.3 H, CH.sub.3
COCH.sub.3 H, CH.sub.3 COCF.sub.3 H, CH.sub.3 COCH.sub.2Cl H,
CH.sub.3 Dye 6-62, Dye 4-60 COCHCl.sub.2 H
COCH.sub.2OC.sub.6H.sub.5 H, CH.sub.3 Dye 4-67, Compound 2
##STR19## R R.sub.1 C(CH.sub.3).sub.3 H C.sub.6H.sub.5 H
CH.sub.2CCl.sub.3 H Compound 3 ##STR20## R R.sub.1
(C.sub.6H.sub.5).sub.2C(CH.sub.3).sub.3 H (CH.sub.3).sub.3 H,
CH.sub.3 (C.sub.3H.sub.7).sub.3 H, CH.sub.3
Manufacturing
[0205] Limited play optical media production involves a number of
manufacturing elements. Typical of these elements are (i)
premastering and/or authoring, which creates the data to be encoded
on each replicated optical media and/or modifies and/or readies the
data to be included on each replicated optical media so that the
data is ready for glass mastering; (ii) glass mastering, which
allows stampers to be created so that each replicated optical media
can be moulded; (iii) replication, whereby individual optical media
are moulded using stampers created in the glass mastering stage and
followed by metallising and/or bonding and/or lacquer coating, in
this element is also the inclusion of the read inhibiting reactive
agent and/or material; (iv) printing of labels on each optical
media; (v) packaging of each optical media into suitable packages;
and (vi) quality assurance, which ensures the optical media meets
necessary specifications regarding quality and/or playability
and/or process controls.
[0206] The aforementioned elements need not occur at a single
facility or under the control of single entity or single
organization. Moreover, additional elements may be added to the
process. Further, all the aforementioned elements are not necessary
in order to have an operable optical media. For example, but not by
way of limitation, it is not necessary that each optical media have
a label printed on it. The above outlined elements need not be
carried out serially and can be carried out in parallel.
Premastering.
[0207] Source data, the data to be encoded on the optical media, is
used to create a disc image on a suitable tape or other format. The
original master of the source data is copied to a specially
prepared master, which is used to produce a master disc prior to
replication. Formats include, for example, Digital Linear Tape
(hereafter "DLT"), U-matic tape, DVD-R, DVD-RAM/-RW, CD, CD-R, 8 mm
Exabyte, and DAT.
[0208] DLT is generally used for transferring DVD data for glass
mastering.
[0209] U-matic tape is used as a digital audio media for
mastering.
[0210] CD and CD-R discs contain necessary TOC and can be used as
the direct input for CD audio and CD-ROM mastering.
[0211] DVD-R discs may be used to transfer the finished data for
glass mastering for DVD-5 discs or DVD-10. DVD-9s cannot be
mastered from DVD-R.
[0212] DVD-RAM and DVD-RW discs cannot be used as input media for
mastering. However, data files can be copied from a DVD-RAM or
DVD-RW and premastered to DLT or DVD-R.
[0213] 8 mm Exabyte tape is physically identical to 8 mm videotape
and can be used for mastering directly. Typically used for audio
applications.
[0214] DAT may be used to master directly from provided certain
parameters are adhered to, such as, certain audio rates are adhered
to.
Glass Mastering.
[0215] Glass mastering is the process of transferring the
premastered data into a stamper that is ready for replication. The
glass master begins as a glass substrate. The surface of the
substrate is cleaned and then coated with a uniform layer of
photo-resist material. For example, in DVD applications the
photo-resist layer thickness is 120 microns.
[0216] The glass master with the photo-resist is placed on the
turntable of a laser beam recorder, where a laser is used to expose
the photo-resist. The laser is modulated to expose the photo-resist
where pits should be, while the glass master spins at exactly the
correct linear velocity and is moved gradually and smoothly to
maintain the correct track pitch and linear velocity.
[0217] After the laser recording the exposed photo-resist surface
is developed to remove the photo-resist exposed by the laser,
creating pits in the surface. The pits extend right through the
photo-resist to the glass underneath. The glass itself is
unaffected by the development process and acts merely as a carrier
for the photo-resist. After the exposed photo-resist is removed the
entire surface is metallised by sputtering a metal layer over the
surface. Examples of metal used to sputter coat the surface include
nickel and silver.
[0218] The metallized glass master is electroplated with a metal,
typically nickel or silver, in a clean room environment to create a
father stamper. This stamper can be used as the stamper for
pressing finished discs; however, to protect the integrity of the
data on the master additional steps are taken to create children
stampers. The father stamper is used to create a mother stamper
through the process of electroforming. Son stampers are created
from the mother stamper, again through the process of
electroforming. The son stampers are then used in the moulding in
the replication of optical media. However, it is not always the
case that son stampers will be used for replication and as will be
further described in the below section.
Replication.
[0219] The finished stamper is fitted to a moulding machine ready
to start moulding the optical media substrates. For example, one
stamper is needed for CDs and one or two for DVDs. Optical media
are made by first moulding the substrate and then metallising
and/or otherwise coating at least one substrate surface with a
reflective material. The metallising and/or reflective coating step
can then be followed with lacquering and/or bonding.
[0220] Moisture is first removed from optical grade polycarbonate.
The moisture free polycarbonate is injection moulded in a high
pressure moulding machine, also known as a press, using the son
stamper mounted in the mould fixed to the press. This mould is in
two parts and provides a cavity, which ensures that perfectly
moulded discs are produced with the correct dimension every time.
One half of the mould contains the stamper (to form the pits) while
the other half contains the mirror block to ensure a smooth
surface.
[0221] The hydraulic press applies to a force to the two halves of
the mould, which are closed. Molten polycarbonate is then injected
into the cavity and held in place by the applied pressure while the
disc cools and solidifies. During cooling the center hole is
punched. After cooling, the press opens and the pressed disc is
transferred to a conveyor to allow the disc to cool before the next
stage. In the case of CDs, only one pressing is needed. In the case
of DVDs, two pressings are needed and each half disc is half as
thick as the single pressing of a CD.
[0222] The polycarbonate discs after moulding are transparent (or
transparent at least to the intended reading beam of optical
reading device the discs are intended for). In certain limited play
optical media applications at least one of the polycarbonate disc
halves is colored. The colorization of at least one polycarbonate
disc half prevents photobleaching when the read inhibiting reactive
agent and/or material is a photochromic dye. Further, the color of
at least one polycarbonate disc half also can prevent a disc
playing in a next generation optical media reading device that
operates at a different laser wavelength. However, the color of the
at least one polycarbonate disc half is selected so that the
wavelength of the intended reading beam will not be interfered with
so that the encoded information can be read until the read
inhibiting agent and/or material is activated.
[0223] At least one polycarbonate disc half of the optical media is
covered by a mirror surface to reflect laser light from a laser
beam of an optical media reading device. The mirror surface allows
the pits and/or other data features to be read by the laser light
of an optical media reading device. Examples of mirror surfaces
include, but not by way of limitation, aluminum and silver. For
example, silver is coated on at least one polycarbonate surface by
sputtering.
[0224] For single substrate optical media a protective coating is
provided to protect the reflective layer from corrosive elements.
For example, CDs typically use aluminum as the reflective layer.
This layer in CDs is protected by a lacquer, which is spread as a
liquid evenly across the surface of the disc by spin coating. The
centrifugal force created by spinning the disc ensures that the
lacquer covers the whole disc in an even layer. It is important
that the lacquer overlap the aluminum thus sealing it from the
elements. If left exposed the aluminum will start to oxidize within
a few days. The lacquer is cured by ultra-violet light, which
produces a hard protective surface. Similar methods can be employed
with Blu-Ray discs.
[0225] For dual substrate optical media the two substrates are
bonded together through the use of adhesives or other bonding
agents. A number of bonding solutions are available and include,
for example and not by way of limitation, hot melt bonding, radical
UV cured bonding which involves a UV cured resin similar to normal
lacquer, cationic UV bonding which involves screen printing the
resin over both substrates and curing each with UV light and then
pushing the discs together.
[0226] In one embodiment of the present invention, and as further
described in U.S. Patent Application Nos. 20030152019, 20030123379,
20030123302, 20030213710, 20030129408, and 20030112737 and as
hereinafter incorporated by reference in their entirety, the read
inhibiting agent and/or material is a constituent of the bonding
material that bonds the two polycarbonate halves together. In this
embodiment, the bonding adhesive is composed of at least two
components that are combined in a predefined manner and under
specified conditions. The combination activates the components. To
allow the combination of the at least two components in-line and
during replication an auto dispense system is utilized. The auto
dispense system can be a combination of pumps or other shaft driven
dispense system that mixes at least two components in predefined
amounts and dispenses the combined product through a static mixing
tube. For example, the dispense system can be composed of a
dispense pump for each component where each component dispense pump
controls the volume of each component dispensed to make the
adhesive; or a dispense pump that dispenses each component using a
single actuator and according to volumetric methods. The auto
dispense system also has the ability to purge the static mixing
tube and associated lines so that the system remains clean and free
from clogs or older material that may contaminate the system.
[0227] Variations on the above described replication process exist
depending on the type of optical media to be replicated. For
example, U.S. Patent Application Nos. 20030152019, 20030123379,
20030123302, 20030213710, 20030129408, and 20030112737, describes
an inverted mastering process for manufacturing limited play DVD-5.
U.S. Patent Application Nos. 20030152019, 20030123379, 20030123302,
20030213710, 20030129408, and 20030112737 are hereinafter
incorporated by reference in their entirety. By way of background,
a DVD disc may contain either one or two information layers for
each substrate, resulting to different types of disc capacities,
such as DVD-5 (single sided, single layer, 4.7 Gbyte capacity),
DVD-9 (single sided, dual layer, 8.5 Gbyte capacity), DVD-10
(double sided, single layer, 9.4 Gbyte capacity), DVD-14 (double
sided, one side single layer, one side dual layer, 13.2 Gbyte
capacity), and DVD-18 (double sided, dual layer, 17 Gbyte
capacity).
[0228] In one embodiment of the invention, the above process is
modified by using the mother stamper to replicate the L1 disc
substrate half of a DVD disc.
[0229] In a long playing standard DVD-5 information is encoded on
the L0 side (the substrate side closest to the reading beam of the
optical reading device) with "pits" and "lands" molded on the L0
substrate and metallized with a reflective coating. In this
embodiment of the current invention, the mother stamper is used to
mold the L1 side. This side is subsequently metallized and bonded
with a blank (i.e., no data encoded substrate) L0 substrate. This
results in the bonding layer in the optical path. Using the
specified layer thickness of 0.055 mm+/-0.015, the thickness of the
L0 substrate is targeted at 0.55 mm to 0.57 mm during molding, to
yield a focal length of the disc thickness (including the bonding
layer) consistent with standard DVD specifications, allowing the
player to be in the normal focusing range for reading a L0 layer.
Thus the player interprets the disc as a standard single layer
DVD-5. Field experience has shown that spacer layer thickness can
be maintained at 0.045 about 0.065 mm consistently in production.
This controlled variation in production along with the reduced
thickness of the molded disc keeps the focus and optics within the
specifications set by the DVD licensing authority and the hardware
manufacturers.
Labeling.
[0230] Optical media printing and finishing options vary, but all
optical media can be printed on using similar technology. It is
also possible to add serialization or other information to the
optical media at this time.
[0231] The upper surface of a finished optical media can be printed
with up to six colors by a flat silkscreen process or offset
printer. Each color requires a different screen created from label
films produced as color separations from the artwork. The inks can
then be cured using UV light to produce a durable surface.
Serialization.
[0232] The burst cutting area is an annular area within the disc
hub where a bar code or other identifying information or
serialization can be written. The BCA can be written during
mastering and will be common for all discs from that master or,
more usually, will be written using a YAG laser to cut the barcode
into the reflective layer of the finished disc.
[0233] In one embodiment of the present invention, serialization is
an integral part in ensuring the quality of the limited play
optical media manufactured. For example, input values for each raw
material used for a production run are input into a data storage
system. These input values will then be linked to a unique bar code
and/or serial number that will be printed on the optical media. If
a problem exists with the optical media the optical media can be
traced back to its input values and run conditions to determine the
source of problem. In this embodiment input values include, but are
not limited to, information on (i) polycarbonate that is used to
create the substrate including born on date, manufacturer lot
number, standard material properties, material identification, and
oxygen diffusion rates, room temperature and humidity storage, bar
code information; (ii) packaging web material used to package the
optical media and allow for a predefined shelf life including born
on date, manufacturer lot number, material identification,
certificate of conformance, storage and shipping conditions since
manufacturing, room temperature and humidity storage conditions and
bar code information; (iii) adhesive part A including bar code
information, born on date, manufacture lot number, material
identification, certificate of conformance, storage and shipping
conditions since manufacturing, room temperature and humidity
storage conditions and bar code information; information on visual
inspection of container seals; (iv) adhesive part B including bar
code information, born on date, manufacture lot number, material
identification, certificate of conformance, storage and shipping
conditions since manufacturing, room temperature and humidity
storage conditions, and bar code information, information on visual
inspection of container seals and ampule color, ampule spectral
reference, measurement of absorbance spectrum, low temperature
storage, dark storage conditions; (v) adhesive part C information
including bar code label information, born on date, material
identification, manufacture lot number, certificate of conformance,
raw material references, visual inspection of container seals, room
temperature and humidity storage conditions; (vi) purge material
information including bar code information, born on date,
certificate of conformance; (vii) reflective sputter target
material information including bar code information, certificate of
conformance,
[0234] In addition, information relating to the internal tracking
of the input materials once on site is cataloged. This information
includes, for example and not by way of limitation, (i)
polycarbonate material is scanned prior to loading dryer; (ii)
packaging material is scanned and cataloged before loading onto
packaging machine, room temperature and storage conditions are
recorded; (iii) the adhesive is inspected and scanned before
longing in auto dispense system and thus the replication machine
information collected includes identification of part A and
validation of shelf life, identification of part B and validation
of shelf life including quality control absorbance spectrum taken a
predetermined time prior to loading on replication machine,
internal mixing system absorbance measurement, identification of
part C and validation of shelf life, identification of purge
material and validation of shelf life; (iv) reflective sputter
target material is identified and validated prior to loading on
replication machine.
[0235] Under this embodiment of the present invention, each
replicated optical media is serialized with a unique identification
number prior to in-line finished optical media scanning. The
serialization forms an identifier to which the above inputs are
traceable and for which the following manufacturing process
variables are identified with the produced optical media. These
manufacturing process variables include, for example, (i) molding
information, which includes lot indicator of polycarbonate source,
actual process values, process set points, and substrate
correlation reference information; (ii) replication information,
which includes lot indicators for adhesive part A, part B, and part
C, purge material, and sputter target material, process information
such as actual process values (i.e., TCS and conveyor
temperatures), process set points, finished optical media
correlation reference; (iii) optical media inspection parameters
and test results, such as, standard DVD-5 inspection parameters,
optical layer thickness, reduced deviation, flow lines,
particulates, manufacturing date and time stamp; (iv) packaging
information, including lot indicators for both top and bottom web
materials, process information from packaging machine, including
date and time stamp, actual process values (i.e., forming
temperature and sealing times); process set points and UV
irradiator status.
Packaging.
[0236] Optical media can be machine packed in a number of different
packages. Some examples include: jewel case, slimline case, amaray
case, super jewel box plus, super jewel box king, card wallets, and
card sleeves. Packaging may also include sealed materials enclosing
the disc and enabling a controlled environment as described in U.S.
Patent Application, Publication No. 2003/0213710, hereafter
incorporated by reference in its entirety. The process parameters
under which a limited play optical disc is package can influence
the overall performance of the limited play optical disc. Process
parameters, such as for example residual oxygen content, activation
levels of scavenging materials included in the package, are
recorded and stored to control batch quality. This information is
part of the raw material input that is logged and linked to the
disc through serialization.
Quality Assurance.
[0237] Quality assurance ensures that the optical media
manufactured meets manufacturing specifications and allows
monitoring of the processes involved in the manufacture of optical
media and as such relates to all the above outlined elements.
Quality assurance is done at the mastering stage to ensure that
stampers with good pit geometry are created. Typical stampers are
played on a disc stamper player. The first disc to be pressed is
verified against the source to ensure that it has been mastered
without errors. The pit geometry of the glass master can be
inspected using a suitable high power microscope.
[0238] Optical media are inspected and tested against a set of
predefined criteria. For example, DVD optical media inspection and
measurements include measurement of tilt and bonding layer
thickness. Test measurements include, for example, reflectivity,
asymmetry checks, 13 signal readings, 114 signal readings, push
pull readings, cross talk readings, jitter measurements,
birefringence measurements, radial noise measurements,
eccentricity, track pitch, scan velocity, begin of lead-in
(hereafter "BLI") measurements, begin of program area (hereafter
"BPL"), begin of lead-out (hereafter "BLO") measurements, radial
and tangential tilt tolerances are recorded.
[0239] The above measured parameters can change with time and
environmental conditions. Thus, part of the quality assurance
includes measurements over time and across different testing
environments. Such test involve, for example, placing sample discs
in an oven at a specified temperature and humidity for a predefined
period of time and then testing and measuring the sample discs
again.
[0240] The foregoing disclosure is not limited the particular
embodiments disclosed. The methods and system outlined above are
not limited or required to be preformed in order and can be
preformed in parallel and/or in a different order than that
disclosed. The present invention relates to any method of tracking
process and material inputs and linking those inputs to a
manufactured limited play optical medium.
[0241] Accordingly, the present invention has been described at
some degree of particularity directed to the exemplary embodiments
of the present invention. It should be appreciated, though, that
the present invention is defined by the following claims
constructed in light of the prior art so that modifications or
changes may be made to the exemplary embodiments of the present
invention without departing from the inventive concepts contained
herein.
* * * * *
References